REVIEW | doi:10.20944/preprints202311.1549.v1
Subject: Medicine And Pharmacology, Other Keywords: bone implants; bioprinting; biocompatible material; bone replacement material; sapphire implants
Online: 24 November 2023 (02:40:17 CET)
Background: Despite the fact that bone reconstructive surgeries are widely practiced worldwide, the search for an ideal bone replacement matetrial is still an open issue. We aimed to provide an overview of the current status of research and developments in this field with a focus on sapphire materials; Methods: A literature search and review was conducted using the PubMed, Scopus, and Embase databases. We searched for literature using the following keywords: bone implants; biocompatible materials; bone replacement material; sapphire implants; Results: Sapphire has a unique combination of mechanical, physical and chemical characteristics thanks to wich it has an excelent biocompatability and biointegrity.Unlike other materials it is incredibly strong and has a high endurance. The successful experience of using this material in medical instrument engineering, dentistry and cardiac surgery shows its benefits; Conclusions: We consider that sapphire is a perspective material for bone replacement implants and researchers should look in this direction.
CASE REPORT | doi:10.20944/preprints202306.1615.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: Cysts; Bone Regeneration; Dental Implants; Case Reports [Publication Type]
Online: 22 June 2023 (12:06:35 CEST)
The odontogenic cysts can lead to a bone destruction that can hamper the dental implant place-ment in the ideal 3D position. Different biomaterials and techniques that allow bone regeneration are described in the literature, each with its advantages and disadvantages. This clinical case with 18 months of follow-up shows the enucleation of an odontogenic cyst fol-lowing the guide bone regeneration with fence technique. After 6 months 2, dental implants were placed at the region of tooth 11 and 21, being rehabilitated nine weeks after. The fence technique allowed the recovery of the bone morphology and the placement of the dental implants in the 3D ideal position.
REVIEW | doi:10.20944/preprints202311.1021.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: cryogels; scaffolds; tissue engineering; bone reconstruction; cartilage reconstruction
Online: 16 November 2023 (02:51:42 CET)
Critical sized bone defects and articular cartilage injuries resulting from trauma, osteonecrosis or age-related degeneration are often nonhealing by the physiological repairing mechanisms, thus representing a clinic issue due to the relevant epidemiological incidence. Current treatment approaches consist of autologous or allogenic grafting, which are associated with painfulness, morbidity, risk of infections and rejection. Novel tissue-engineering approaches, aiming at the reconstruction of damaged tissues, have been proposed as alternative solutions to these conven-tional methods. These approaches are based on the combination of three fundamental compo-nents: autologous or allogenic cells, a scaffold and growth-stimulating signals, which are gener-ally referred to as the tissue engineering triad. Three-dimensional polymer networks are fre-quently used as scaffolds to allow cell proliferation and tissue regeneration. In this scenario, cryogels are giving promising results as cell scaffolds over other polymer networks, thanks to their peculiar properties. In particular, cryogels possess an interconnected porous structure and a typical sponge-like behaviour, which facilitate the cellular infiltration and ingrowth. Their properties can be appropriately adjusted to match the requirements of the specific tissue or or-gan that it is intended to regenerate. In this review it is reported the state of the art on the fabri-cation and employment of cryogels in supporting osteo or chondro-genic differentiation for the re-building of more organized tissues. Moreover, it will highlight current progress and future perspectives in the implementation of this technology in the clinical practice.
ARTICLE | doi:10.20944/preprints202308.1140.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: modified chitosan; polyelectrolyte complex CH-SA-HA; rats; type I diabetes mellitus; bone critical size cavity; morphological reconstruction; histomorphometric criteria
Online: 16 August 2023 (05:40:23 CEST)
It is known that complexes based on natural polysaccharides are able to eliminate bone defects. Prolonged hyperglycemia means low bone regeneration and a chronic inflammatory response. The purpose of the study was to increase the efficiency of early bone formation in a cavity of critical size in diabetes mellitus in the experiment. The polyelectrolyte complex contains high molecular ascorbate of chitosan, chondroitin sulfate, sodium hyaluronate, heparin, adgelon serum growth factor, sodium alginate and amorphous nanohydroxyapatite (CH-SA-HA). Studies were conducted on 5 groups of white female Wistar rats: group 1 - regeneration of a bone defect in healthy animals under a blood clot; group 2 - regeneration of a bone defect under a blood clot in animals with diabetes mellitus; group 3 - bone regeneration in animals with diabetes mellitus after filling the bone cavity with a collagen sponge; group 4 - filling of a bone defect with a CH-SA-HA construct in healthy animals; Group 5 - filling of a bone defect CH-SA-HA in animals with diabetes mellitus. Implantation of the CH-SA-HA construct into bone cavities in type I diabetic rats can accelerate the rate of bone tissue repair. The inclusion of modifying polysaccharides and apatite agents in the construction may be a prospect for further improvement of the properties of implants.
ARTICLE | doi:10.20944/preprints202307.0843.v1
Subject: Medicine And Pharmacology, Endocrinology And Metabolism Keywords: Bone histomorphometry; Bone-nervous system interactions; Bone-fat; Neuropeptide Y
Online: 12 July 2023 (12:13:47 CEST)
The impact of obesity upon bone metabolism is controversial since both negative and positive effects have been reported. Bone remodeling is modulated by the central nervous system through cytokines, hormones and neuromodulators. The present study aimed to evaluate the effects evoked by bilateral retroperitoneal white adipose tissue (rWAT) denervation (Dnx) upon bone mineral metabolism and remodeling in an experimental model of obesity in rats. Male Wistar rats were fed during 18 weeks with high-fat diet (HFD) or standard diet (SD) as controls, and rWAT Dnx or Sham surgery was performed at the 14th week. Biochemical and hormonal parameters, bone histo-morphometry, rWAT and hypothalamus protein and gene expression were analyzed. HFD group presented decreased bone formation parameters, increased serum and bone leptin and FGF23, increased serum and hypothalamic neuropeptide Y (NPY) and decreased serum 1,25-dihydroxyvitamin D3 and PTH. After rWAT Dnx, bone markers and histomorphometry showed restoration of bone formation, serum and hypothalamic NPY decreased, without altera-tion in leptin levels. The present study showed that the denervation of rWAT improved bone formation in obese rats mediated by a preferential reduction in neurohormonal actions of NPY, emphasizing the relevance of the adipose tissue-brain-bone axis in the control of bone metabolism in obesity.
ARTICLE | doi:10.20944/preprints202301.0491.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Bone healing; bone fracture; herbal medicine; osteogenesis; bone alkaline phosphatase
Online: 27 January 2023 (06:31:59 CET)
Medicinal plants for bone grafts are promising because they are free from infecting microorganisms and biocompatible. We report a novel study evaluating osteoregeneration of bone grafts from extracts of Alternanthera brasiliana and Fridericia platyphylla after bone injury induced by radius fracture in rats. Grafts were obtained using 2% chitosan gel and 0.5% hydroalcoholic extract. The rats were randomly divided into four experimental groups (N= 12): Negative control (NC) - Chitosan gel; Positive control (PC) - bovine mineral bone graft (Lumina Bone®, fine powder 0.5); F. platyphylla Graft (FRID) - 0.5% bone graft; A. brasiliana Graft (ABRA) - 0.5% bone graft. The animals were evaluated for three periods, 30, 60, and 90 days after fracture induction. Bone alkaline phosphatase (BSAP) and radiographic and histological evaluations were followed. After 90 days, there was an increase in BSAP for the ABRA group on the newly formed bone matrix but not for FRID, indicating the presence of active osteoblasts. Additionally, mature bone tissue and bone remodeling were observed, and a conspicuous presence of type I collagen for both FRID and ABRA. We demonstrated that FRID and ABRA grafts produced early bone neoformation. New perspectives for these species as a graft are suggested.
REVIEW | doi:10.20944/preprints202301.0462.v1
Subject: Medicine And Pharmacology, Veterinary Medicine Keywords: Bone healing; , bone fracture; bone graft; herbal medicine; osteogenesis; plants
Online: 26 January 2023 (02:58:19 CET)
Objectives Bone fractures are very common diseases, which can be caused by impact injuries or physiological disorders. Thus, the present review aimed to study the use of medicinal plants in the healing mechanism of bone fractures. Evidence acquisition Through research in the PubMed, Google Academic, and Scielo databases, this article reviews 11 ethnopharmacological studies and 34 preclinical studies on the biological actions of different plants in bone fracture healing mechanism. Results Indian tribes have highlighted in the plants ethnopharmacological study for various diseases, including bone fractures. However, despite the large citations of traditional use, technical-scientific studies are still scarce in the literature. Chenopodium ambrosioides, Piper sarmentosum, quadrangular Cissus, Ricinus communis and Radix salvia miltiorrhiza plants were the most studied in the literature regarding their osteogenic, angiogenic, anti-inflammatory and remodeling effects, acting on bone receptors, stimulating bone metabolism, increasing minerals uptake, and assisting in free radicals breakdown. Conclusion Thus, the medicinal plants use is promising in the field of bone regeneration, as well as being alternative when conventional therapies are unfeasible, increasing herbal medicines demand and popularity.
ARTICLE | doi:10.20944/preprints202106.0545.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Bone tissue regeneration; injectable; bone graft; fracture; osteoblast; bone tissue engineering
Online: 22 June 2021 (14:22:33 CEST)
The occurrence of bone-related disorders and diseases has increased dramatically in recent years around the world. Demineralized bone matrix (DBM) has been widely used as a bone implant due to its osteoinduction and bioactivity. However, the use of DBM is limited because it is a particulate material, which makes it difficult to manipulate and implant with precision, in addition, these particles are susceptible to migrate to other sites. To address this situation, DBM is commonly incorporated into a variety of carriers. An injectable scaffold has advantages over bone grafts or preformed scaffolds, such as the ability to flow and fill the bone defect. The aim of this research is to develop a DBM carrier with such viscoelastic properties to obtain an injectable bone substitute (IBS). The DBM carrier developed consisted of a PVA/glycerol network cross-linked with borax and reinforced with CaCO3 as a pH neutralizer, porosity generator, and source of Ca. The physicochemical properties were determined by the injectability test, FTIR, SEM, and TGA. Porosity, degradation, bioactivity, possible cytotoxic effect, and proliferation in osteoblasts were also determined. The results show that the developed material has great potential to be used in bone tissue regeneration
REVIEW | doi:10.20944/preprints202304.0484.v1
Subject: Medicine And Pharmacology, Pharmacy Keywords: bone regeneration; bone cells; bone biomarkers; bone signaling pathways; plants extracts; phytochemicals compounds; nanometric systems; nanostructured scaffolds
Online: 18 April 2023 (04:41:03 CEST)
Bone metabolism is a complex process which is influenced by the activity of bone cells (e.g., osteocytes, osteoblasts, osteoclasts), the effect of some specific biomarkers (e.g., parathyroid hormone, vitamin D, alkaline phosphatase, osteocalcin, osteopontin, osteoportegerin, osterix, RANKL, Runx2) and the characteristic signaling pathways (e.g., RANKL/RANK, Wnt/β, Notch, BMP, SMAD). Some phytochemical compounds such as flavonoids, tannins, polyphenols, anthocyanins, terpenoids, polysaccharides, alkaloids and others presented a beneficial and stimulating effect in the bone regeneration process due to pro-estrogenic activity, antioxidant and anti-inflammatory effects and modulation of bone signaling pathways. Lately, nanomedicine has emerged as an innovative concept for new treatments in bone related pathologies envisaged by incorporation of medicinal substances in nanometric systems for oral or local administration, as well as in nanostructured scaffolds with huge potential in bone tissue engineering.
ARTICLE | doi:10.20944/preprints202311.0871.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: animal study; bone healing; histology; lateral augmentation; bone transplantation; biomaterial; bone defect
Online: 14 November 2023 (11:16:45 CET)
Background: Xenogenous bone has been proposed as an alternative to overcome the disadvantages of autogenous grafting. The aim of the present study was to study bone dynamics at inlay and onlay xenografts used for bone augmentation applying a ring technique. Methods: The bone at the lateral surface of the mandibular angle of 12 adult male New Zealand White rabbits was exposed bilaterally. The cortical layer received multiple perforations at one side of the mandible and a xenograft block of collagenated cancellous equine bone, 7 mm in diameter and 3 mm in width, was fixed on the prepared surface using an implant (onlay group). On the opposite side, a defect 7 mm in diameter and 3 mm in depth was prepared, the xenograft block was adapted to the defect and fixed with an implant (inlay group). Results: After ten weeks of healing, in the onlay grafts, new bone was mainly formed on the trabeculae surface, reaching in some specimens the most coronal regions of the block. In the inlay grafts, new bone was found arranged on the trabecular surfaces but also occupying the spaces among the trabeculae. The entrance of the defect was often found close at the top of the block by newly formed bone. A higher percentage of new bone was found in the inlay (19.0 ±9.3%) compared to the onlay (10.4 ±7.4%) groups (p=0.031). The mean gain in osseointegration at the implant in relation to the base of the original 3 mm deep defect was 0.95 ±1.05% at the onlay group and 0.78 ±0.71% at the inlay group (p=0.603). Conclusion: The inlay grafts exhibited a higher new bone percentage than the onlay grafts possibly due to the defect conformation that presented more sources for bone formation. The trabecular conformation and the composition of the grafts made possible the expression of the osteoconductive properties of the material used. This resulted, in several specimens, in growth of bone on the graft trabeculae toward the most superior regions in both groups, and in the closure of the coronal entrance of the defects in the inlay group.
ARTICLE | doi:10.20944/preprints202309.0756.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: animal study; bone healing; histology; lateral augmentation; bone transplantation; biomaterial; bone defect
Online: 13 September 2023 (05:48:08 CEST)
Background: The conformation of the recipient site for an inlay graft presents an increased contact with the parent bone compared to the onlay graft. This might favor bone growth within the inlay compared to the onlay grafts. Hence, the objective of this study was to compare bone incorporation and remodeling process of xenogeneic en bloc grafts, placed using two bone grafting techniques, i.e., onlay vs. inlay. Methods: In this prospective, randomized, split-mouth study (test and control sides in the same animal), two bone grafting techniques were comparatively evaluated on the lateral aspect of the rabbit mandibles. One side was prepared with perforations (onlay site), whereas the other side was prepared with trephines and drills to obtain a wide (7 mm) standardized recipient site (inlay site). A xenogeneic bone block was fixed in the center with a titanium screw in both sides of the mandible and covered with a collagen membrane. Two healing periods were applied in the study: 2 and 10 weeks of healing. Results: after 2 weeks of healing, the mean percentage of new bone was 10.4% and 23.3% at the onlay and inlay grafts, respectively (p=0.022). After 10 weeks of healing, new bone increased to 13.2% and 25.4%, respectively (p=0.080). In this period of healing, the inlay grafts presented new bone percentage >20% in all regions examined while the onlay graft presented a lower percentage in the most external regions of the graft. Conclusion: The percentage of new bone increased faster and was higher in the inlay compared to the onlay grafts. The composition of the grafts allowed new bone to reach the most peripheral regions in both graft groups, even though it was higher in the inlay group. A marginal closure of the defects by newly formed bone was observed in the inlay group.
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: allograft, resorption, sclerotic bone, exfoliation, bone failure
Online: 24 April 2019 (12:33:49 CEST)
AbstractCadaver bone is possibly the most common transplant material used today. Common types of cadaver bone transplants are freeze-dried bone allografts and xenografts. Studies have shown that mineralized freeze-dried bone allografts have the same percentage of retained bone graft particles at different time points, indicating that these materials are never resorbed. However, it is commonly accepted by clinicians that these materials are resorbed and convert the graft site into normal bone. This histologic study was undertaken to determine the fate of mineralized freeze-dried bone allograft particles grafted into human extraction sockets. Materials and Methods:This study is a photographic, radiologic, and histological analysis of mineralized freeze-dried bone allograft healing in human sockets after mineralization at different time points. The mineralized freeze-dried bone allografts used for evaluation in this study were particulate bone graft materials in maxillary or mandibular extraction sockets. Patient selection was random, based on the following time periods: 6 months, 2 years, 5 years, 7 years, 10 years and 15 years. No block bone grafts were evaluated. Results:No resorption of cadaver bone graft particles was found at any time point. No osteoclasts were found in any of the histology at any time point. At different time points from 6 months through 15 years, mineralized freeze-dried bone allograft particles were found to be exfoliated out of the alveolar crest as a result of the formation of a hypervascular zone surrounding the grafted site. The embedded graft particles remain embedded in sclerotic bone until the particles reach the alveolar crest at which time the sclerotic bone and graft particles break up and are released into the gingiva. All histologic samples from 6 months to 15 years contained residual graft particles. The sclerotic bone formed around graft particles did not integrate to the graft particles or the implant surface. Conclusions:Mineralized freeze-dried bone allograft particles are not resorbed after mineralization. A hypervascular zone forms around the grafted site and exfoliates the bone graft particles into the gingiva. The mineralization process produces sclerotic bone which never remodels into normal bone. Sclerotic bone covers but does not integrate to the retained bone graft particles or implant surface resulting in a weakened structure with an increased likelihood of bone failure and implant loss.
ARTICLE | doi:10.20944/preprints202311.1090.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Hydroxyapatite; Salmon Bone; Bone Repair; Osteoregeneration; Process; Biomaterial
Online: 17 November 2023 (08:43:27 CET)
Salmon aquaculture generates a substantial volume of waste material, offering potential for biomaterial production. This industry produces significant waste, which can be repurposed for various biological applications, particularly in biomaterial production for tissue engineering with pertinent applications in osteo-conduction, osteo-induction, and clinical/surgical bone regeneration and repair. The process involves a standardized pre-treatment stage aimed at minimizing biological waste content. Subsequently, the treatment stage, contingent on the chosen methodology, facilitates the removal of proteins, lipids, and other compounds, leaving the mineral phase as a valuable substrate. The selection of the optimal method, whether alkaline hydrolysis, calcination, or NaOH hydrolysis, for obtaining this substrate necessitates thorough examination through chemical, physical, and biological assessments, including Raman Spectroscopy and X-Ray Diffraction. This study aims to identify the most efficient approach for hydroxyapatite production derived from salmon waste.
ARTICLE | doi:10.20944/preprints202201.0004.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: Critical illness; Osteoporosis; Bone turnover; Bone metabolism; Treatment
Online: 4 January 2022 (12:29:45 CET)
Critical illness has been recognized to acutely influence bone metabolism and, consequently, bone mineral density. The main purpose of this study was to describe bone metabolism changes in adult survivors of critical illness in the attempt to correlate changes with severity scores. It is an open, prospective, observational, monocentric study on patients admitted to the ICU was conducted, evaluating bone metabolism at baseline (within 72 hours of ICU admission), 6 months, and 12 months. Fifty-nine patients admitted to the ICU (63% males), mean age 58 ± 16 years, were enrolled. Of these, 20 patients (34%) completed the one-year follow up. At baseline, bone resorption showed an increase, which was maintained at 6 months, with normalization at 12 months. Patients showed, in a majority of cases, hypovitaminosis D with hyperparathyroidism at baseline with subsequent normalization. A trend towards a correlation was described between severity scores and serum 25(OH) vitamin D and bone turnover marker levels. These results contribute to the confirmation of a positive association between critical illness requiring ICU and bone metabolism changes. This study poses the bases for further studies to evaluate bone health in ICU patients.
REVIEW | doi:10.20944/preprints202103.0502.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Physical activity; bone vascularization; angiogenesis; VEGF; bone repair
Online: 19 March 2021 (14:47:50 CET)
Physical activity is widely recognized as a biotherapy by WHO in the fight and prevention of bone diseases such as osteoporosis. It reduces the risk of disabling fractures associated with many comorbidities, and whose repair is a major public health and economic issue. Bone tissue is a dynamic supportive tissue that reshapes itself according to the mechanical stresses to which it is exposed. Physical exercise is recognized as a key factor for bone health. However, the effects of exercise on bone quality depend on exercise protocols, duration, intensity and frequency. Today, the effects of different exercise modalities on capillary bone vascularization, bone blood flow and bone angiogenesis remain poorly understood and unclear. As vascularization is an integral part of bone repair process, the analysis of the preventive and/or curative effects of physical exercise is currently very undeveloped. Angiogenesis-osteogenesis coupling may constitute a new way for understanding the role of physical activity, especially in fracturing or in the integration of bone biomaterials. Thus, this review aims to clarify the link between physical activities, vascularization and bone repair.
ARTICLE | doi:10.20944/preprints202309.1989.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: bioactive materials; bone grafts; remineralization; coatings; bone tissue engineering; demineralized bone matrix; biomimetic scaffolds; calcium phosphate-albumin composite; bone marrow biomimetic
Online: 28 September 2023 (11:17:19 CEST)
In the present study, the efficiency of a biomimetic approach by coating demineralized bone matrix (DBM) amorphous calcium phosphate (DBM+CaP), including its combination with serum albumin (DBM+CaP+BSA), was investigated. The intact structure of DBM promotes the transformation of amorphous calcium phosphate (CaP) into DPCD with a characteristic plate shape and particle size of 5–35 µm. The inclusion of BSA in the coating resulted in a better and more uniform distribution of CaP on the surface of DBM trabeculae. MG63 cells showed that both the obtained forms of CaP and its complex with BSA did not exhibit cytotoxicity up to a concentration of 10 mg/ml in vitro. Ectopic (subcutaneous) implantation in rats revealed pronounced biocompatibility, as well as strong osteoconductive, osteoinductive, and osteogenic effects for both DBM+CaP and DBM+CaP+BSA, but more pronounced effects for DBM+CaP+BSA. In addition, for the DBM+CaP+BSA samples, a pronounced full physiological intrafibrillar biomineralization and proangiogenic effect with the formation of bone-morrow-like niches, accompanied by pronounced processes of intramedullary hematopoiesis, indicating a powerful osteogenic effect of this composite have been achieved.
ARTICLE | doi:10.20944/preprints202305.0422.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: shell nacre; ormocer; bone void filling cement; bone defects
Online: 6 May 2023 (10:57:53 CEST)
Shell nacre from Pinctada species has been extensively researched for managing bone defects. However, there is a gap in the research on using shell nacre as cement with improved physico-chemical properties. To address this, the current study aimed to develop a chemical curable com-posite shell nacre cement (SNC) using shell nacre powder and an organically modified ceramic resin shell nacre containing ladder-structured siloxane methacrylate (SNLSM). Different amounts of shell nacre (24, 48, and 72 weight(wt)%) were added to the SNLSM resin matrix and the effect on the physicochemical properties of the cement was studied. The composite shell nacre cement SNC 72 containing 72 wt% shell nacre exhibited significantly higher mechanical properties (com-pressive strength >100 MPa, flexural strength > 35 MPa) and low linear polymerization shrinkage (0.4%) than other compositions. SNC 72 was radiopaque and the exotherm generated during the curing of the cement was minimal. Direct contact of cured SNC 72 with L929 cells revealed the non-cytotoxic nature of the cement. Overall, the results of the study proved that the composite SNC 72 would be a promising candidate for bone defect management.
ARTICLE | doi:10.20944/preprints202101.0571.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: bioactivity; bone; dentistry
Online: 27 January 2021 (16:35:15 CET)
In the pursuit of better treatments, the concept of a chemically-active material, responding to local conditions by causing reactions, or reacting to produce substances that are deemed beneficial, seems laudable. Ultimately, the goal appears to be to recruit natural biological processes such that a natural ‘repair’ is effected. This goal seems to be the reason for prefixing “bio-“ to many terms with a view to advertising the desire, yet without presenting evidence that it has occurred, or indeed that it is capable of occurring, relying instead on non-biological processes to justify the claims. The dogma is such that all work where local ‘responsive’ chemistry is involved must receive the label “bioactive” to legitimize and promote. Nevertheless, the primary evidence adduced is flawed, and the claim must fail. A rethink to restore scientific sense and confidence in the endeavour is essential if real progress is to be made.
REVIEW | doi:10.20944/preprints202310.1023.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: cardiac amyloidosis; cardiomyopathies; HFpEF; bone scintigraphy; bone tracers; multidisciplinary teams
Online: 17 October 2023 (05:22:36 CEST)
This review will deal with the most relevant unmet needs and clinical questions concerning scintigraphy with bone tracers in ATTR-CA, providing expert opinions on possible future developments in the clinical application of these radiotracers, in order to offer practical information for interpretation of nuclear images to physicians involved in the care of patients with this ATTR-CA.
REVIEW | doi:10.20944/preprints202309.0966.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: osteoimmunology; rheumatoid arthritis; erosions; spondyloarthritis; bone tissue; new bone formation
Online: 14 September 2023 (08:23:05 CEST)
Several rheumatologic diseases are primarily distinguished by their involvement of bone tissue, where it not only serves as a mere target of the condition but often plays a pivotal role in its pathogenesis. This scenario is particularly prominent in chronic inflammatory arthritis such as rheumatoid arthritis (RA) and spondyloarthritis (SpA). Given the immunological and systemic nature of these diseases, in this review, we report an overview of the pathogenic mechanisms underlying the specific bone involvement, focusing on the complex interactions that occur between bone tissue's own cells and the molecular and cellular actors of the immune system, a recent and fascinating field of interest defined osteoimmunology. Specifically, we have comprehensively elaborated on the distinct pathogenic mechanisms of bone erosion seen in both rheumatoid arthritis and spondyloarthritis, as well as the characteristic process of aberrant bone formation observed in spondyloarthritis. Lastly, chronic inflammatory arthritis lead to systemic bone involvement, resulting in systemic bone loss and consequent osteoporosis, along with increased skeletal fragility.
REVIEW | doi:10.20944/preprints201807.0443.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: genetic factors; dental implants; bone quality; bone regeneration; success rate
Online: 24 July 2018 (06:01:10 CEST)
Dental implants provide a predictable treatment option for partial and complete edentulism via the placement of fixed permanent artificial root to support prosthetic dental crowns. Despite the high survival rates, long-term implant failures are still reported leading to implant removal and additional financial and health burdens. While extrinsic factors that improve survival rate of implants have been well explored, the impact of genetic factors on this matter is poorly understood. A systematic review and meta-analysis study was conducted to determine whether genetic factors contribute to increase the risk of dental implant failure. A comprehensive search for peer-reviewed articles on dental implants and genetics was performed using various literature database libraries. The study design was conducted according to PRISMA guidelines, and the obtained records were registered in PROSPERO database. According to the exclusion/inclusion criteria, 11 studies were eligible for this study out of 808 articles. The meta-analysis of the combined association studies of DNA variations and dental implants did not indicate an increase risk for implant failure due to DNA variations in IL-1B, IL-10 and TNF-α. This study emphasizes the need for larger randomized controlled clinical trails to inform clinicians and patients about the role of genetic factors on dental implant survival and success rate in healthy and compromised patients.
ARTICLE | doi:10.20944/preprints202210.0436.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Additive manufacturing; Biomaterials; Bone; Bone regeneration; Critical Bone Defects; Hydroxy-apatite nanoparticles; Polycaprolactone; Polyethylene glycol diacrylate; Scaffolds
Online: 28 October 2022 (02:15:21 CEST)
Notwithstanding the advances achieved in the last decades in the field of synthetic bone substitutes, the development of biodegradable 3D scaffolds with ideal mechanical and biological properties remains an unattained challenge. In this work, a novel approach is explored to produce synthetic bone grafts mimicking the complex bone structure using additive manufacturing. For the first time, scaffolds were produced, using an extrusion technique, composed of a thermoplastic polymer, polycaprolactone (PCL), hydroxyapatite nanoparticles (HANp), and polyethylene glycol diacrylate (PEGDA). These scaffolds were further compared with two groups of scaffolds: one composed of PCL and another of PCL and HANp. After production, optimisation and characterisation of these scaffolds, an in vitro evaluation was performed using human dental pulp stem/stromal cells (hDPSCs). Through the findings it was possible to conclude that PEGDA scaffolds were successfully produced presenting networks of interconnected channels, presenting hydrophilic properties (15.15 4.06°), adequate mechanical performance (10.41MPa 0.934), and allowing a cell viability significantly superior to the other groups analysed. To conclude, findings in this study demonstrated that PCL, HANp and PEGDA scaffolds may have promising effects on bone regeneration and might open new insights for 3D tissue substitutes.
REVIEW | doi:10.20944/preprints202310.1747.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: extraglandular steroidogenesis; de novo steroidogenesis; steroid hormones; bone metabolism; osteoclast; osteoblast; osteocyte; bone tumors; bone metastasis; pregnenolone derivates
Online: 26 October 2023 (18:54:46 CEST)
Steroid hormone production by adrenal cortex, gonads and placenta (so called glandular steroidogenesis) is responsible for the endocrine control of the body’s homeostasis and organized by a feedback regulatory mechanism based on the hypothalamus-pituitary-steroidogenic gland axis. On the other hand, recently discovered extraglandular steroidogenesis occurring locally in different tissues is rather linked to paracrine or autocrine signaling and it is independent of the control by the hypothalamus and pituitary. Bone cells, such as bone-forming osteoblast, osteoblast-derived osteocytes and bone-resorbing osteoclasts respond to steroid hormones produced by both glandular and extraglandular steroidogenesis. Recently, new techniques to identify steroid hormones as well as synthetic steroids and steroidogenesis inhibitors have been introduced, which greatly empowered steroid hormone research. Based on recent literature and new advances in the field, here we review the local role of steroid hormones in regulating bone homeostasis and skeletal lesion formation. The novel idea of extraglandular steroidogenesis occurring within the skeletal system raises the possibility of the development of new therapies for the treatment of bone diseases.
REVIEW | doi:10.20944/preprints202310.1082.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: multi-scale; hierarchical structure; porous scaffold; bone tissue engineering; bone regeneration
Online: 18 October 2023 (02:34:08 CEST)
In recent decades, porous scaffolds for bone tissue engineering (BTE) have gained significant attention. Considerable research efforts have been dedicated to investigating the impact of scaffold pore size on a diverse array of biological processes, including cell-scaffold interactions, substance transportation, and vascularization. However, the multi-scale hierarchical porosity, a key structural characteristic of natural bone, has rarely been replicated in BTE scaffolds due to the challenges of controlling the scaffold structure across multiple length scales. With the advancement of manufacturing technology, there has been increasing research on biomimetic multi-scale hierarchical materials, which are also gaining favor in the field of BTE. Therefore, there is an urgent need to review multi-scale hierarchical porous BTE scaffolds. This paper aims to review the role and fabrication methods of multi-scale porous BTE scaffolds at different length scales, the design and manufacturing of new BTE scaffolds for bone regeneration.
REVIEW | doi:10.20944/preprints202308.1315.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: non-leaching antibacterial bone cement; acrylic bone cement; contact-kill; biomaterials
Online: 18 August 2023 (07:24:37 CEST)
Antibiotic-loaded bone cements are widely used in orthopedic surgery. However, they present issues such as a short antibiotic release time and the antibiotic resistance. These challenges necessitate the development of novel antibacterial bone cements. Non-leaching bone cement containing antibacterial motifs represents a promising advancement in this direction. Antibacterial motifs are incorporated into the cement either covalently or non-covalently, and while they will not be released, they will still exhibit surface antibacterial activity. This review comprehensively examines the structure and antimicrobial activity of prevalent non-leaching antimicrobial bone cements. Additionally, it delves into the characteristics of current methods employed for detecting surface antimicrobial activity. Finally, the future research direction of non-leaching antibacterial bone cement is discussed, with a specific focus on innovative antibacterial motifs, the mechanisms underlying non-leaching antibacterial properties, and the potential synergies achievable by combining non-leaching antibacterial bone cement with traditional antibiotics.
REVIEW | doi:10.20944/preprints202307.1738.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Sericin; Bone graft applications; Biocompatibility; Immune responses; Tissue engineering; Bone healing
Online: 26 July 2023 (09:10:58 CEST)
The potential of sericin, a protein derived from silkworms, is explored in bone graft applications. Sericin's biocompatibility, hydrophilic nature, and cost-effectiveness make it a promising candidate for enhancing traditional graft materials. Its antioxidant, anti-inflammatory, and UV-resistant properties contribute to a healthier bone-healing environment, and its incorporation into 3D-printed grafts could lead to personalized medical solutions. However, despite these promising attributes, there are still gaps in our understanding. The precise mechanism through which sericin influences bone cell growth and healing is not fully understood, and more comprehensive clinical trials are needed to confirm its long-term biocompatibility in humans. Furthermore, the best methods for incorporating sericin into existing graft materials are still under investigation, and potential allergic reactions or immune responses to sericin need further study.
ARTICLE | doi:10.20944/preprints202306.1576.v1
Subject: Computer Science And Mathematics, Computer Vision And Graphics Keywords: Mask R-CNN; Double U-Net; Deeplabv3 +; bone segmentation; bone scintigraphy
Online: 21 June 2023 (15:47:29 CEST)
Bone Scan Index (BSI) is an image biomarker for quantification on bone metastasis of cancers. To compute BSI, not only the hotspots (metastasis) but also the bones have to be segmented. Most related researches focus on binary classification on bone scintigraphy: having metastasis or none. Rare studies focus on pixelwise segmentation. In this study we compare three advanced convolutional neural network (CNN) based models to explore the bone segmentation on dataset in house. The best model is Mask R-CNN, which reaches the precision, sensitivity and F1-score: 0.93, 0.87, 0.90 for prostate cancer patients and 0.92, 0.86, 0.88 for breast cancer patients, respectively. The results are the average of 10-fold cross-validation, which reveals the reliability for clinical use on bone segmentation.
ARTICLE | doi:10.20944/preprints202301.0058.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Bone Tissue Engineering; Bone Scaffold; Citric Acid; Silk Resin; Compression Molding
Online: 4 January 2023 (03:37:54 CET)
Thermoplastic molded regenerated silk was proposed as structural material in tissue engineering applications, mainly for application in bone. The protocol allows to obtain a compact non-porous material with a compression modulus in the order of a Giga Pascal starting from silk fibroin by compressing a silk fibroin lyophilized sponge of powder in mold at temperature higher than the glass transition temperature (Tg). The main purpose of the produced resin was the osteofixation and other structural applications in which the lack of porosity was not an issue. In this work, we introduced the use of citric acid in the thermoplastic molding protocol of SF to obtain a porosity inside the structural material. In addition to the previously developed protocols the addition of citric acid allowed us to obtain a structural material. The CA powder during the compression acted as a template for the pore formation. In addition, the CA was able to effectively crosslink the SF chain improving the mechanical strength. This effect was proved both evaluating the compression modulus and by studying the spectra obtained by Fourier infrared spectroscopy (FTIR). This protocol may be applied in the near future to the production of a structural bone scaffold.
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: tissue-level; bone-level; dental implants; transmucosal; marginal bone loss; review
Online: 13 July 2020 (03:18:26 CEST)
Purpose: to assess any differences on marginal bone loss between bone-level or tissue-level dental implants through a review of literature until September 2019. Materials and methods: MEDLINE, Embase and other database were searched by two independent authors. The search was limited to articles in English. Results: The search provided 1028 records and, after removing the duplicates through titles and abstracts screening, 45 full-text articles were assessed for eligibility. For qualitative analysis 20 articles were included, 17 articles of them for quantitative analysis. A total of 1161 patients (mean age 54,4 years) and 2933 implants were observed, 1427 (Tissue-level) and 1506 (Bone-level). The survival rate and the success rate were more than 90%, except for 2 studies with a success rate of 88% and 86.2%. No studies reported any differences between groups in term of success and survival rates. Three studies showed that BL-implants had statistically less marginal bone loss (P< 0.05). Only one study reported statistically less marginal bone loss in TL-implants (P< 0.05). In the most part of the studies, differences between implant types in marginal bone loss were not statistically significant. Conclusion: Despite to the peri-implant tissue around transmucosal implants has been reported to be inﬂammation-free because of the absence of bacterial infiltration in the micro-gap between the fixture and abutment, no clinical and radiological differences were highlighted between groups from the included studies after a variable period of follow-up ranged between 1 to 5 years.
CASE REPORT | doi:10.20944/preprints201710.0069.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: bone block; allograft; tissue reaction; Guided Bone Regeneration (GBR); CAD/CAM
Online: 11 October 2017 (12:12:53 CEST)
The objective of this case report is to introduce a customized CAD/CAM freeze-dried bone allograft (FDBA) block for its use in Guided Bone Regeneration (GBR) procedures for severely deficient maxillary bones. Additionally, a special newly developed remote incision technique is presented to avoid wound dehiscence. The results show an optimal integration behaviour of the FDBA block after six months and the formation of new vital bone. Thus, the results of the present case report confirm the use of the customized CAD/CAM bone block for augmentation of complex defects in the maxillary aesthetic zone as a successful treatment concept.
ARTICLE | doi:10.20944/preprints202109.0166.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Octacalcium phosphate (OCP); Hydroxyapatite (HA); Biphasic calcium phosphate (BCP); Xeno-genic bone; Synthetic bone; Bone Regeneration; Phase conversion; Mineralization
Online: 9 September 2021 (08:23:32 CEST)
Octacalcium phosphate (OCP) is a precursor of biological apatite crystals that has attracted attention as a possible bone substitute. On the other hand, few studies have examined this material at the experimental level due to the limitations of OCP mass production. Recently, mass production technology of OCP was developed, and the launch of OCP bone substitutes is occurring. In this study, the bone regeneration capacity of OCP products was compared with two of the most clinically used materials: heat-treated bovine bone (BHA) and sintered biphasic calcium phosphate (BCP). Twelve rabbits were used, and defects in each tibia were filled with OCP, BHA, BCP, and left unfilled as control (CON). The tibias were harvested at 4 and 12 weeks, and 15 μm slides were prepared using the diamond grinding method after being embedded in resin. Histological and histomorphometric analyses were performed to evaluate the bone regeneration ability and mechanism. The OCP showed significantly higher resorption and new bone formation in both periods analysed (p<0.05). Overall, OCP bone substitutes can enhance bone regeneration significantly by activating osteoblasts and a rapid phase transition of OCP crystals to biological apatite crystals (mineralisation), as well as providing additional space for new bone formation by rapid resorption.
ARTICLE | doi:10.20944/preprints202308.1032.v2
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: experimental critical size bone defect; maxillofacial area; chitosan; bone formation; morphometry; rats
Online: 6 October 2023 (08:32:17 CEST)
Abstract: A biomaterial is proposed for closing extensive bone defects in the maxillofacial region. The composition of the biomaterial includes high-molecular chitosan, chondroitin sulfate, hyaluronate, heparin, alginate and inorganic nanostructured hydroxyapatite. The purpose of the study is to demonstrate morphological and histological early signs of reconstruction of a bone cavity of critical size. The studies were carried out on 84 white female rats weighing 200-250 g. The study group consisted of 84 subjects in total, 40 in the experimental group and 44 in the control group. In all animals, three-walled bone defects measuring 0.5 x 04 x 05 cm were applied subperiosteally in the region of the angle of the lower jaw and filled in experimental group using lyophilized gel mass of chitosan-alginate-hydroxyapatite (CH-SA-HA). In control animals, the bone cavities were filled with an auto-blood clot after bone trepanation and bleeding. The observation periods are 3.5.7 days, 188.8.131.52.8 and 10 weeks. The control of bone regeneration was carried out using multiple morphological and histological analyses. Results showed that following implantation the chitosan construct actively replaced early-stage defects with the formation of a full-fledged new bone tissue as compared to the control group. Already, by the 7th day morphological analysis showed that formation of spongy bone tissue could be seen. After 2 weeks there was a pronounced increase in bone volume (P<0.01), and at 6 weeks after surgical intervention the closure of the defect was 70-80%, after 8 weeks - 100% without violation of bone morphology with a high degree of mineralization. Thus, the use of modified chitosan after filling eliminates bone defects of a critical size in the maxillofacial region, reveals early signs of bone regeneration, and serves as a promising material in reconstructive dentistry.
Subject: Medicine And Pharmacology, Endocrinology And Metabolism Keywords: Hyperthyroid; Hypothyroid; Euthyroid; Vitamin D; Bone Turn Over Markers; Bone Mineral Density
Online: 23 September 2020 (04:52:34 CEST)
Thyroid hormones have a catabolic effect on bone homeostasis. Hence, this study aimed to evaluate serum vitamin D, calcium, and phosphate and bone marker levels and bone mineral density (BMD) among patients with different thyroid diseases. This cross-sectional study included patients with underlying thyroid diseases (n=64, hyperthyroid; n=53 euthyroid; and n=18, hypothyroid) and healthy controls (n=64). BMD was assessed using z-score and left hip and lumbar bone density (g/cm2). Results showed that the mean serum vitamin D Levels of all groups was low (<50 nmol/L). Thyroid patients had higher serum vitamin D levels than healthy controls. All groups had normal serum calcium and phosphate levels. The bone marker levels were significantly high in the hyperthyroid group and low in the hypothyroid group. The z-score for hip and spine did not significantly differ between thyroid patients and control groups. The hip bone density was remarkably low in the hyperthyroid group. In all groups, the serum vitamin D levels were below the cutoff value. However, thyroid patients had a higher serum vitamin D level than healthy controls. The carboxy terminal collagen crosslink and procollagen type I N-terminal propeptide levels were high in hyperthyroid patients and low in hypothyroid patients. Further, hyperthyroid patients had a low hip BMD.
ARTICLE | doi:10.20944/preprints202310.2094.v1
Subject: Public Health And Healthcare, Health Policy And Services Keywords: micronutients; functional foods; olive paste; bone mineral density; bone metabolism biomarkers; postmenopausal women
Online: 31 October 2023 (12:25:22 CET)
(1) Background : Low dietary intake of calcium, vitamin D, vitamin C and magnesium has been associated with increased risk of osteoposrosis. The purpose was to evaluate changes in biomarkers of bone metabolism, and cardiometabolic health in postmenopausal women, with high risk of osteoporosis, followed by a nutritional intervention program. (2) Method: It was a prospective randomized controlled trial. A sample of 115 apparently healthy postmenopausal women(45 -75 years of age) randomized into four groups: (I) nutritional intervention group(n=40) received daily 1000mg vitamin C, 500mg vitamin D3, 500mg calcium(Ca) and 300mg magnesium (Mg); (II) control group(n=42) received daily 500mg vitamin D3, 500mg Ca and 300mg Mg; (III) nutritional intervention group (n=18) received daily 150mg bisphosphonates, 500mg vitamin D3, 500mg Ca and 300mg Mg; and (IV) nutritional intervention group (n=15) received daily about 364 mg polyphenols via an innovative functional food (50g olive paste enriched with mountain tea extract) along with 500mg vitamin D3, 500mg Ca and 300mg Mg. Groups I -III received supplementation for a year whereas group IV for 5 months. Changes in calciregulatory hormone parathormone (PTH) were evaluated at the beginning of the study as well as at 5 and 12 months intervals. Blood levels of vitamin D, vitamin C, Ca, Mg and the lipid profile were assessed at the beginning and at the end of the study. Anthropometric indices (weight, body fat(Kg), Body Mass Index(BMI) and bone mineral density(BMD) were evaluated at the beginning and at the end of the study. Statistical analysis was performed with IBM-SPSS Statistics-21. The level of statistical significance was set at p<0.05. (3) Results: 25(OH)D3 levels were improved, in groups II, III and IV (+3,71% and +1.45% and +5.62% respectively). PTH levels were increased at the end of the intervention period, for groups I and IV. Significant positive changes recorded, in total BMD, in all four study groups. Significant beneficial changes for total cholesterol was observed in group IV (-2.07%, P<0.05) and positive changes in group I for HDL biomarker (+61.62%, P<0.05) (4) Conclusions:. Additional larger-scale clinical trials and intervention studies are considered essential, in order to fully investigate and elucidate associations between dietary components and biochemical indices of bone metabolism.
REVIEW | doi:10.20944/preprints202307.0308.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: bone, cartilage; extrinsic innervation; genicular nerve; intrinsic innervation; joint pain; osteoarthritis; subchondral bone
Online: 5 July 2023 (11:50:03 CEST)
Pain in osteoarthritis (OA) results from erosion of joint cartilage, resulting in bone contacting bone without an intervening cushion. The periosteum, including its nociceptive innervation, ends at the border of the cartilage meaning that there is no extrinsic neuronal pathway between the opposing denuded bone surfaces to carry a bone-on-bone pain signal to the brain. The pain signaling pathway must therefore originate in nociceptive sensory endings within the subchondral bone itself. Selective ablation of this intrinsic nerve pathway, using any of a variety of approaches, is expected to permanently eliminate OA pain.
ARTICLE | doi:10.20944/preprints202302.0207.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: Chronic kidney disease; bone remodeling; static bone histomorphometry; inorganic phosphate transporters; intracellular signaling
Online: 13 February 2023 (08:46:13 CET)
Background: Initial phases of molecular and cellular maladaptive bone response at early CKD remain mostly unknown. Methods: We induced mild CKD in SHRs by either arterial hypertension lasting six months (sham-operated rats, SO6) or in its’ combination with 3/4 nephrectomy lasting two and six months (Nx2 and Nx6, correspondently). Sham operated SHRs (SO2) and Wistar Kyoto rats (WKY2) with two-month follow-up served as controls. Animals were fed standard chow containing 0.6% phosphate. We measured creatinine clearance, urine albumin-to-creatinine ratio, renal interstitial fibrosis, inorganic phosphate (Pi) exchange, intact PTH and FGF23, Klotho, dickkopf-1, sclerostin. And assessed bone response by static histomorphometric indices and gene expression profiles. Results: Mild CKD groups had no increase in renal Pi excretion, FGF23 and PTH levels. Serum Pi, dickkopf-1, and sclerostin were higher in Nx6. Decrease in trabecular bone area and osteocyte number was obvious in SO6. Nx2 and Nx6 had additionally lower osteoblast number. The decline in eroded perimeter was only apparent in Nx6. Significant downregulation of genes related to Pi transport, MAPK, WNT, and BMP signaling accompanied histological alterations in Nx2 and Nx6. Conclusions: We found an association of mild CKD with histological and molecular features suggesting lower bone turnover, which occurred at normal levels of systemic Pi-regulating factors.
ARTICLE | doi:10.20944/preprints202107.0563.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: sandblasted implants; acid-etched implants; taper connection; marginal bone remodeling; marginal bone loss
Online: 26 July 2021 (10:25:54 CEST)
Aim: the purpose of the present prospective, case series study were to report implant survival rate and marginal bone remodeling expected five years after loading using dental implants placed in in the daily practice. Material and Methods: this research was designed as an open-cohort, prospective case series study. Any completely or partially edentulous patients scheduled to receive at least one bone leve were considered eligible for this study. Primary outcomes were: cumulative implant (ISR) and prosthetic (PSR) survival rates, and any complications experienced up the five years follow-up. Secondary outcomes were: marginal bone remodeling, implant insertion torque, implant stability quotient (ISQ), and thickness of gingival biotype. Results: ninety consecutive patients (34 males and 56 females; mean age 53.2±15.4 years; range of 24–81 years), 243 implants were placed and followed for at least five years after loading (mean of 65.4±3.1 months; range of 60–72 months). The mean implant insertion torque was 42.9±4.8 Ncm (range from 15 to 45 Ncm). Overall, 83.5% of the implants (n=203) were placed with an insertion torque between 35 and 45 Ncm. At the one year follow-up, no drop-outs were recorded, but 17 patients (18.9%) with 18 restorations (12.6%) delivered on 34 implants (14%) were lost at the five years examination. At the five-year examination, six implants failed in six patients, resulting in a cumulative ISR of 97.5%. At the five-year follow-up, four prostheses failed (2.8%) resulting in a cumulative PSR of 97.2%. At the five-year examination, five complications were reported by five different patients, resulting in a prosthetic success rate of 96.5%, measured at patient level. Five years after loading, mean MBL was 0.41 ± 0.30 mm (95% CI: 0.26–0.34). Difference from the one year data was 0.04 ± 0.19 mm (95% CI: 0.01–0.07). The mean ISQ value at implant placement was 71.6 ± 5.5 (range of 45–88). Six months later, the mean ISQ was 76.7 ± 4.4 (range of 66–89). The difference was statistically significant (P=0.0001). Statistically significant higher MBL was found for smokers, and patient with thin gingival biotype. Conclusions: High implant survival and success rates could be expected with stable marginal bone remodeling up to five years after loading. Smoking and thin tissue biotype were the most important variabilities associated with higher MBL. Further research are needed to confirm these results.
ARTICLE | doi:10.20944/preprints202102.0443.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: critical sized bone defect; bone tissue regeneration; nano-gelatin/ hydroxyapatite fiber (NGF); metformin.
Online: 19 February 2021 (14:35:11 CET)
Tissue engineering and regenerative medicine has gradually evolved as a promising therapeutic strategy to the modern healthcare of the aging and diseased population. In this study, we developed a novel nano-fibrous scaffold and verified its application in the critical bone defect regeneration. The metformin-incorporated nano-gelatin/hydroxyapatite fibers (NGF) was produced by electrospinning, cross-linked, and then characterized by XRD and FTIR. Cytotoxicity, cells adhesion, cell differentiation, and quantitative osteogenic gene and protein expression were analyzed by bone marrow stem cells from rat. Rat forearm critical bone defect model was performed for the in vivo study. The nano-gelatin/hydroxyapatite fibers (NGF) were characterized by their porous structures with proper interconnectivity without significant cytotoxic effects; the adhesion of bone marrow stem cells on the nano-gelatin/hydroxyapatite fibers (NGF) could be enhanced. The osteogenic gene and protein expression were upregulated. Post implantation, the new regenerated bone in bone defect was well demonstrated in the NGF samples. We demonstrated that the metformin-incorporated nano-gelatin-hydroxyapatite fibers greatly improved healing potential on the critical sized bone defect. Although metformin-incorporated nano-gelatin/hydroxyapatite fibers had advantageous effectiveness during bone regeneration, further validation is required before it can be applied to clinical applications.
REVIEW | doi:10.20944/preprints201806.0432.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Bone tissue engineering; biomaterials; bone scaffolds; additive manufacturing techniques/robocasting; marine-derived biomaterials
Online: 26 June 2018 (16:05:49 CEST)
Bone is a dynamic tissue with the capacity of repair and regeneration in specific conditions. Nevertheless, due to the increased incidence of bone disorders, the need of bone grafts has been growing over the past decades and the development of an ideal bone graft with optimal properties remains a clinical challenge. This review addresses the bone properties (morphology, composition and their repair and regeneration capacity) and puts the main focus on the potential strategies for developing bone repair and regeneration materials. It describes the requirements for designing a suitable scaffold material, types of materials (polymers, ceramics and composites) and techniques to obtain the porous structures (additive manufacturing techniques/robocasting or derived from marine skeletons) for bone tissue engineering applications. The main objective of this review is to gather the knowledge on the materials and methods for the production of scaffolds for bone tissue engineering and highlighting the potential of natural porous structures such as marine skeletons as promising alternative bone graft substitute materials without any further mineralogical changes, or after partial or total transformation into calcium phosphate. The suitability of the marine-derived porous bone graft substitutes for the intended applications will be also discussed.
REVIEW | doi:10.20944/preprints202311.0142.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: pericyte; osteogenesis; bone defect; regeneration
Online: 2 November 2023 (09:55:56 CET)
Pericytes, as perivascular cells, are present in all vascularized organs and tissues, and they actively interact with endothelial cells in capillaries and microvessels. Their involvement includes functions like blood pressure regulation, tissue regeneration, and scarring. Studies have confirmed that pericytes play a crucial role in bone tissue regeneration through direct osteodifferentiation processes, paracrine actions, and vascularization. Recent pre-clinical and clinical experiments have shown that combining perivascular cells with osteogenic factors and tissue-engineered scaffolds can be therapeutically effective in restoring bone defects. This approach holds promise for addressing bone-related medical conditions. In this review, we have emphasized the characteristics of pericytes and their involvement in angiogenesis and osteogenesis. Furthermore, we have explored recent advancements in the use of pericytes in preclinical and clinical investigations, indicating their potential as a therapeutic resource in clinical applications.
REVIEW | doi:10.20944/preprints202309.2108.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: bone; disease; renal; children; osteodystrophy
Online: 14 October 2023 (18:40:46 CEST)
Intense alterations of mineral and bone metabolism are prevalent in chronic kidney disease (CKD) and represent an important cause of morbidity and decreased quality of life. These disor-ders have traditionally been defined as renal osteodystrophy and classified based on bone biop-sy, but due to a lack of bone biopsy data and validated radiological methods to evaluate bone morphology in children, it has been difficult to adequately evaluate renal osteodystrophy in pe-diatric CKD. This has led to suboptimal management of bone disorders in children. CKD-mineral and bone disorder (CKD-MBD) is a new term used to describe a systemic disorder of mineral and bone metabolism as a result of CKD. CKD-MBD is a triad of biochemical imbalances of cal-cium, phosphate, parathyroid hormone and vitamin D, bone abnormalities and soft tissue calci-fication. This literature review aims to explore the pathogenesis, diagnostic approach, and treat-ment of CKD-MBD in children and the specific consequences of renal osteodystrophy on growing skeleton, with a specific focus on the biological basis of this peculiar condition.
REVIEW | doi:10.20944/preprints202308.1785.v1
Online: 25 August 2023 (11:50:54 CEST)
Fractures are the most common large organ trauma in humans. The initial inflammatory re-sponse promotes bone healing during the initial post-fracture phase, but chronic and persistent inflammation due to infection or other factors does not contribute to the healing process. The precise mechanisms by which immune cells and their cytokines are regulated in bone healing remain unclear. The use of mesenchymal stem cells (MSCs) for cellular therapy of bones injury is a novel clinical treatment approach. Bone progenitor MSCs not only differentiate into bone, but also interact with the immune system to promote the healing process. We review in vitro and in vivo studies on the role of the immune system and bone marrow MSCs in bone healing and their interactions. A deeper understanding of this paradigm may provide clues to potential therapeu-tic targets in the healing process, thereby improving the reliability and safety of clinical applica-tions of MSCs to promote bone healing.
ARTICLE | doi:10.20944/preprints202206.0203.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: Gilbert Syndrome; Deferiprone; bone deformity
Online: 14 June 2022 (10:18:06 CEST)
Gilbert Syndrome, is a benign condition characterized by persistent indirect hyperbilirubinemia due to reduced UDP-glucuronyltransferase enzyme activity. Its coexistence with other clinical disorders has important clinical and pharmacological implications. GS is known to coexist with many hemolytic conditions and may lead to diagnostic difficulty and also increased incidence of gallstones. UGT1A1 gene has been shown to be involved in the conjugation of various physiologically important endogenous and exogenous compounds, so individuals with Gilbert mutation (the variant allele UGT1A1*28) have an increased risk of toxicity of various drugs and endogenous compounds like irinotecan, steroid hormones, implicated in various human carcinoma like colorectal and breast carcinoma. Deferiprone (DFP) is an orally available chelator used in the management of iron overload in patients with Transfusion Dependent Thalassemia (TDT). In this study, fifteen out of 275 patients with TDT, had a deferiprone-induced joint deformity. Among these fifteen patients with joint deformity, eleven patients (four patients were homozygous for TA 7 repeats and seven were heterozygous for TA7 repeats) had associated gilbert mutation. Therefore, we hypothesize that patients of TDT who had underlying Gilbert mutation might have decreased enzymatic activity of UGTIA6, which metabolizes the DFP, leading to more prominent adverse effects related to DFP.
CASE REPORT | doi:10.20944/preprints201808.0378.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: Bone resorption, Device, Tooth extraction
Online: 21 August 2018 (13:49:34 CEST)
Aim: In a human pilot case, we used a root formed temporary prosthetical device (Intra-alveolar Device - IAD), to investigate the effect of mechanical stimulation on hard tissue clinically and radiographically. Background: The extraction of a tooth determines the resorption of the alveolar bone. This determines challenge to place an implant and to integrate the prosthesis in soft tissue. Mechanical stimulation is fundamental for bone tropism but is not understood the effect of mechanical stimulation on post-extraction site. Case presentation: A 24 years old woman was enrolled. The IAD’s were used as expected by protocol. Clinical healing was uneventfully. Vertical radiographical bone resorption measured on CBCT was -0,14mm (5,6%) while horizontal bone resorption was -0,21mm (12,36%). Conclusion: This study demonstrated the feasibility of the proposed model. We need clinical prospectical studies enrolling more patients
ARTICLE | doi:10.20944/preprints202308.1566.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: immunohistochemistry; foreign body reaction; bone defect; scaffold-guided bone regeneration; polycaprolactone; in vivo; sheep
Online: 23 August 2023 (05:29:15 CEST)
Large volume bone defect regeneration is complex and demands time to complete. Several regeneration phases with unique characteristics including immune responses follow, overlap, and interdepend on each other and, if successful, lead to the regeneration of the organ bone's form and function. However, during traumatic, infectious, or neoplastic clinical cases, the intrinsic bone regeneration capacity may exceed, and surgical intervention is indicated. Scaffold-guided bone regeneration (SGBR) has recently shown efficacy in preclinical and clinical studies. To investigate different SGBR strategies over periods of up to 3 years we have established a well characterized large segmental tibial bone defect ovine model, for which we have developed and optimized immunohistochemistry (IHC) protocols. We present an overview of the immunohistochemical characterization of different experimental groups in which all ovine segmental defects were treated with a bone grafting technique combined with a three-dimensionally printed medical-grade polycaprolactone-tricalcium phosphate (mPCL-TCP) scaffold. The qualitative data set is based on osteoimmunological findings gained from IHC analyses of over >350 sheep surgeries over the past two decades. Our systematic and standardized IHC protocols enabled us to gain further insight into the complex and long-drawn-out bone regeneration processes, which ultimately proved to be a critical element for successful translational research.
ARTICLE | doi:10.20944/preprints202308.0719.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: IGF-I; knockout; bone; chondrocyte; osteoblast; endochondral ossification; epiphysis; sec-ondary spongiosa; bone mass
Online: 9 August 2023 (10:52:29 CEST)
To evaluate the relative importance of IGF-I expression in various cell types for endochon-dral ossification, we quantified the trabecular bone at the secondary spongiosa and epiphysis of the distal femur in 8-12-week-old male mice with a global knockout of the Igf-I gene as well as conditional deletion of the Igf-I gene in osteoblasts, chondrocytes, osteo-blasts/chondrocytes, and their corresponding control wild type littermates. The osteoblast-, chondrocyte- and osteoblast/chondrocyte-specific Igf-I conditional knockout mice were generated by crossing Igf-I floxed mice with Cre transgenic mice in which Cre expression is under the control of Col1α2 or Col2α1 promoter. We found that global disruption of Igf-I resulted in 80% and 70% reduction in bone size, which is defined as total volume, at the secondary spongiosa and epiphysis of the distal femur, respectively. Abrogation of Igf-I in Col1α2-producing osteoblasts, but not Col2α1-producing chondrocytes, decreased bone size by 25% at both the secondary spongiosa and epiphysis while deletion of the Igf-I globally or specifically in osteoblasts or chondrocytes reduced trabecular bone mass by 25%. By contrast, global Igf-I knockout but not conditional knockout of Igf-I in osteoblasts and/or chondrocytes reduced trabecular bone mass in the epiphysis. The reduced trabecu-lar bone mass at the secondary spongiosa in osteoblast- and/or chondrocyte-specific Igf-I conditional knockout mice is caused by reduced trabecular number and increased trabec-ular separation. Immunohistochemistry studies revealed that expression levels of chon-drocyte (COL10, MMP13) and osteoblast (BSP) markers were reduced in the secondary spongiosa and the epiphyses in the global Igf-I knockout mice. Our data indicate that local and endocrine IGF-I actions in bone are pleiotropic and dependent on cell type as well as the bone compartment where IGF-I acts.
ARTICLE | doi:10.20944/preprints202301.0141.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: tibialis anterior tendon; attachment site area; three-dimensional; medial cuneiform bone; first metatarsal bone
Online: 9 January 2023 (06:36:49 CET)
The purpose of this study was to clarify the attachment types of the tibialis anterior tendon (TAT) in Japanese fixed cadavers and to determine the attachment site area in three dimensions. We examined 100 feet from 50 Japanese cadavers. The TAT was classified according to differences in the number of fiber bundles as: Type I, with one fiber bundle; Type II, with two fiber bundles; and Type III, with three fiber bundles. The attachment site area of the TAT was measured using a three-dimensional scanner. Cases were Type II in 95% and Type III in 5%, with no cases of Type I identified. In Type II, mean attachment site areas were 85.2 ± 18.2 mm2 for the medial cuneiform bone (MCB) and 72.4 ± 19.0 mm2 for the first metatarsal bone (1MB), showing a significantly larger area for MCB than for 1MB. These findings suggest the possibility of ethnic differences in TAT attachment types and suggest that TAT attachments in Japanese individuals are highly likely to be Type II, with rare cases of Type III. Accurate measurement of attachment site areas is possible with appropriate three-dimensional measurements.
ARTICLE | doi:10.20944/preprints202309.1504.v2
Subject: Biology And Life Sciences, Life Sciences Keywords: dual release, daptomycin, BMP-2, β-TCP scaffold, ADA-gelatin gel, bone infection, bone regeneration
Online: 24 November 2023 (08:41:16 CET)
Background: Antibiotic-containing carrier systems are one option that offers the advantage of releasing active ingredients over a longer period of time. In vitro sustained drug release from a carrier system consisting of microporous β-TCP ceramic and alginate has been reported in previous works. Alginate dialdehyde (ADA) gelatin gel showed both better mechanical properties when loaded into a β-TCP ceramic and higher biodegradability than pure alginate. Methods: Dual release of daptomycin and BMP-2 was measured on days 1, 2, 3, 6, 9, 14, 21, and 28 by HPLC and ELISA. After release, the microbial efficacy of the daptomycin was verified and the biocompatibility of the composite was tested in cell culture. Results: Daptomycin and the model compound FITC protein A (n=30) were released from the composite over 28 days. A Daptomycin release above the minimum inhibitory concentration (MIC) by day 9 and a burst release of 71.7 ± 5.9 % were observed in the loaded ceramics. Low concentrations of BMP-2 were released from the loaded ceramics over 28 days.
ARTICLE | doi:10.20944/preprints202309.1948.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: Biofilm; silver; bone; nanotechnology; impregnation; bacteria
Online: 28 September 2023 (13:23:37 CEST)
Introduction: Silver nanoparticles have been extensively investigated in dental and orthopedic materials. However, the impregnation of bone graft with silver nanoparticles has been poorly investigated. Objectives: The aim of this study was to evaluate the in vitro antibiofilm activity of a bovine bone impregnated with silver nanoparticles. Methods: Bone scaffolds from cancellous bovine femur were used for the tests and impregnated with silver nanoparticles (50nm) by physical adsorption. Silver nitrate minimal inhibitory and bactericidal concentration were performed Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Enterococcus faecalis, Acinetobacter baumannii, and Escherichia coli. Disc diffusion tests for silver nanoparticles susceptibility and quantification of biofilm production on plate and bone with sessile cell count were also performed. Results: All pathogens were susceptible to silver with low minimal inhibitory concentration (0.25 – 4 mg/L). The scaffold impregnated with silver nanoparticles presented a significant reduction in the biofilm cells for all microorganisms with a reduction of more than 3 logs in colony forming units count. Conclusion: Bone scaffolds impregnated with silver nanoparticles can significantly reduce biofilm, and it can be a strategical material to be used as an implant for different approaches.
ARTICLE | doi:10.20944/preprints202308.1520.v1
Subject: Engineering, Bioengineering Keywords: computer model; trabecular bone; electrical conductivity
Online: 22 August 2023 (08:13:57 CEST)
Background: Electrical conductivity of trabecular bone at 100 kHz was recently reported as a good predictor of bone volume fraction. However, to quantify its relationship with the free water (or physiological solution) content and between the conductivities of its constituents, is still unclear. Methods: In this contribution, in silico models inspired by microCT images of trabecular bovine samples were used to build realistic geometries. Finite Element Method was applied to solve the electrical problem and to robustly fit the conductivity of the constituents with literature data. The obtained effective electrical conductivity was compared to Bruggeman three media mixture model: physiological solution, bone marrow and bone matrix. Results: The values for physiological solution plus bone marrow and bone matrix that captured better the bone volume fraction in the two media Finite Element model were: σps+bm = 298.4 mS/m and σb = 21.0 mS/m, respectively. Additionally, relative good results were obtained by a three media Bruggeman mixture model with σbm= 103 mS/m, σb= 21.0 mS/m, and σps= 1200 mS/m. Simple linear relationships between the proportions of constituents depending on bone volume fraction were tested. Degree of anisotropy and fractal dimension do not show detectable changes in effective conductivity. Conclusions: These results provided some useful findings for simulation purposes: first, a higher value of electrical conductivity of bone marrow has to be used in order to obtain similar values to those experimental published data. Second, anisotropy is not detectable by conductivity measurements for small trabecular samples (cube 5 mm). Finally, the simulations presented here showed a relatively good fitting of the mixture Bruggeman model which potentially would allow both, accounting for the free water content and re-scaling the model for whole bone electrical simulations.
REVIEW | doi:10.20944/preprints202307.1099.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: Bone Tumour; hyperparathyroidism; giant cell; osteoclast
Online: 17 July 2023 (10:20:10 CEST)
Osteitis fibrosa cystica (OFC) and Brown Tumour are two related but distinct types of bone lesions that result from overactivity of osteoclasts most often associated with chronic kidney disease (CKD). Despite their potential consequences, these conditions are poorly understood because of their rare prevalence and variability in their clinical manifestation. Canonically, OFC and Brown Tumours are caused by secondary hyperparathyroidism in CKD. Recent literature showed that multiple factors such as hyperactivation of the renin-angiotensin-aldosterone system and chronic inflammation may also contribute to the occurrence of these diseases through osteoclast activation. Moreover, hotspot KRAS mutations were identified in these lesions placing them in the spectrum of RAS-MAPK-driven neoplasms, while until recently thought to be reactive lesions. Some risk factors contributed to the occurrence of OFC and Brown Tumour such as age, gender, comorbidities, and certain medications. The diagnosis of OFC and Brown Tumour includes clinical symptoms involving chronic bone pain and laboratory finding of hyperparathyroidism. In radiological imaging, the X-ray and Computed tomography (CT) scan could show lytic or multi-lobular cystic alterations. Histologically both lesions are characterized by clustered osteoclast in a fibrotic hemorrhagic background. Based on the latest understanding of the mechanism of OFC, this review elaborates on the manifestation, diagnosis, and available therapies that can be leveraged to prevent the occurrence of OFC and Brown Tumour.
ARTICLE | doi:10.20944/preprints202307.0274.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: platelet; bone mineral density; megakaryocyte; RANKL
Online: 5 July 2023 (10:51:58 CEST)
A potential association between hematopoietic stem cell status in the bone marrow and the surrounding bone tissue has been hypothesized, and some studies have investigated the link between blood count and bone mineral density (BMD), although their exact relationship remains controversial. Moreover, biological factors linking the two are largely unknown. In our present study, we found no clear association between platelet count and BMD in the female group, with aging having a very strong effect on BMD. On the other hand, a significant negative correlation was found between platelet count and BMD in the male group. As a potential mechanism, we examined whether megakaryocytes, the source of platelet production, secrete cytokines that regulate BMD, namely OPG, M-CSF, and RANKL. We detected the production of these cytokines by megakaryocytes deriving from bone marrow mononuclear cells and found that RANKL was negatively correlated with BMD. This finding suggests that RANKL production by megakaryocytes may mediate the negative correlation between platelet count and BMD. To our knowledge, this is the first report to analyze bone marrow cells as a mechanism for the association between blood count and BMD. Our study may provide new insights into the development and potential treatment of osteoporosis.
ARTICLE | doi:10.20944/preprints202305.1838.v1
Subject: Medicine And Pharmacology, Endocrinology And Metabolism Keywords: pancreatic neuroendocrine neoplasms; bone metastasis; biomarker
Online: 26 May 2023 (04:11:51 CEST)
We investigated the diagnostic capacity of selected circulating biomarkers (CBMs) for the early detection of bone metastasis (BMets) in patients with pancreatic neuroendocrine neoplasms (PanNENs). 115 patients with PanNENs and 40 controls were enrolled. We measured the serum levels of ferritin, cytokeratin 18 (CY18), CA19-9, CA125, AFP, CEA, and beta-2 microglobulin (B2M). 8 PanNENs patients developed BMets, and 107 remained BMets-free. We observed a significantly higher level of CA125 and CY18 in BM-PanNENs patients vs. non-BM-PanNENs patients (p = 0.01 and p = 0.04, respectively). CA125, CY18, and B2M area under receiver operator characteristic (AUROC) analyses differentiated BM-PanNENs from non-BM-PanNENs patients; CA125 area under the curve (AUC) 0.77, p < 0.01; CY18 AUC data were 0.72, p = 0.03, and B2M AUC 0.67, p = 0.02. Based on CBMs metrics in both subgroups, we reached a sensitivity/specificity for CA125 of 75/76%; for CY18 of 75/69%, for B2M of 100/50%, for CA125 and CY18 combination 93/90%, respectively. The useful CBMs for BM-PanNENs patients detection were CA125, CY18, and B2M. They seem to have the diagnostic capacity as a fair single biomarker and CA125&CY18 combination panel for the detection of BMets.
REVIEW | doi:10.20944/preprints202208.0380.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Osteoarthritis; pathophysiology; subchondral bone; synovium; inflammation
Online: 22 August 2022 (10:44:18 CEST)
ABSTRACT: Understanding the basis of osteoarthritis (OA) has seen some interesting advancements in recent years. It has been observed that cartilage degeneration is preceded by subchondral bone lesions, suggesting a key role of this mechanism within the pathogenesis and progression of OA, including the formation of ectopic bone and osteophytes. Moreover, low-grade, chronic inflammation of the synovial lining has gained a central role in the definition of OA pathophysiology, and central immunological mechanisms, innate but also adaptive, are now considered crucial in driving inflammation and tissue destruction. In addition, the role of neuroinflammation and central sensitization mechanisms has been characterized as underlying causes of pain chronicity. This has led to a renewed definition of OA, which is now intended as a complex multifactorial joint pathology caused by inflammatory and metabolic factors underlying joint damage. Since this evidence can directly affect the definition of the correct therapeutic approach to OA, an improved understanding of these pathophysiological mechanisms is fundamental. This review provides an overview of the most updated evidence on OA pathogenesis; it presents the most recent insight on the pathophysiology of OA, describing the interplay between immunological and biochemical mechanisms proposed to drive inflammation and tissue destruction, as well as central sensitization mechanisms. Moreover, although the therapeutic implications consequent to the renewed definition of OA are beyond this review scope, some suggestions for intervention have been addressed.
ARTICLE | doi:10.20944/preprints201811.0363.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: Bone; Osteoclasts; Osteoblasts; Oat Bran; Osteoporosis
Online: 15 November 2018 (11:38:53 CET)
The number of patients with bone metabolic disorders including osteoporosis is increasing worldwide. These disorders often facilitate bone fractures, which seriously impact the patient’s quality of life and could lead to further health complications. Bone homeostasis is tightly regulated to balance bone resorption and formation. However, many anti-osteoporotic agents are broadly categorized as either bone forming or anti-resorptive, and their therapeutic use is often limited due to unwanted side effects. Therefore, safe and effective therapeutic agents are needed for osteoporosis. This study aims to clarify the bone protecting effects of oat bran water extract (OBWE) and its mode of action. OBWE inhibited RANKL-induced osteoclast differentiation by blocking c-Fos/NFATc1 through the alteration of I-κB. Furthermore, we found that OBWE enhanced BMP-2-stimulated osteoblast differentiation by the induction of Runx2 via Smad signaling molecules. In addition, the anti-osteoporotic activity of OBWE was also evaluated using an in vivo model. OBWE significantly restored ovariectomy-induced bone loss. These in vitro and in vivo results showed that OBWE has the potential to combat bone metabolic disorders including osteoporosis
ARTICLE | doi:10.20944/preprints201801.0062.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: octacalcium phosphate; bone matrix gelatin; osteogenesis
Online: 9 January 2018 (03:14:28 CET)
Objective: Regeneration of bone defects remains a challenge for maxillofacial and reparative surgeons. The purpose of this histological study was to assess the osteogenic potential of octacalcium phosphate (OCP) and bone matrix gelatin (BMG) alone and in combination in artificially created mandibular bone defects in rats. The quality of the newly formed bone was also evaluated. Methods: Thirty-six male Sprague Dawley rats (6-8 weeks old with 120-150 g weight) were randomly divided into four groups. Defects (3 mm in diameter and 2 mm in depth) were created in the mandible of rats and filled with 6 mg of OCP, BMG or a combination of both (1/4 ratio), respectively. Defects were left unfilled in the control group. To assess osteoinduction and bone regeneration and determine the quality of the newly formed bone, tissue specimens were harvested at seven, 14, and 21 days post-implantation. The specimens were processed, stained with hematoxylin and eosin (H&E) and histologically analyzed under light microscopy. Results: In the experimental groups, new bone formation was initiated at the margins of defects from seventh day after implantation. At the end of the study period, the amount of the newly formed bone increased and the bone was relatively mature. Osteoinduction and new bone formation were greater in OCP/BMG group. In the control group, slight amount of new bone had been formed at the defect margins (next to host bone) on day 21. Conclusion: Combination of OCP/BMG may serve as an optimal biomaterial for treatment of mandibular bone defects.
ARTICLE | doi:10.20944/preprints201709.0102.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: drug screening； bone mineralization； osteoclast； zebrafish
Online: 21 September 2017 (06:34:11 CEST)
Currently, drug screening is primarily based on human cell culture for initial high-throughput screening, and subsequently, rodent model to confirm the biological effects. However, the mammalian system is known for time-consuming and highly-cost to be difficult to perform high-throughput drug screening, which exists a critical gap between in vitro cell-based models and the in vivo mammalian models. Therefore, the zebrafish could bridge this gap in preclinical toxicity screening along the drug development pipeline because of its efficiency. We aimed to develop an in vivo zebrafish platform for rapid drug screening. Zebrafish, due to its high genomic conservation with mammals and rapid development and differentiation, it has many advantages, such as short life span, large number of offspring and low cost, easy manipulation for generating transgenic species, to serve as animal model for disease-based research. In 96-well microplates, zebrafish embryos were incubated with small molecular compounds that affected bone mineralization. The level of osteogenic mineralization was evaluated by fluorescent dye staining and quantified by image analysis software. Quantitative real time-PCR (qRT-PCR) was performed to evaluate the biological pathways involved in bone metabolism at the molecular level. The system was validated by demonstrating that response to alendronate and Dorsomorphin in zebrafish. In our study, we screened for 24 compounds within the CYCU-1120~1152 chemical library and identified 3 compounds, pentamidine (CYCU-1140), BML-267 (CYCU-1147), and alendronate (CYCU-1152), increased embryonic mineralization; while 6 compounds, RWJ-60475 (CYCU-1126), levamisole HCL (CYCU-1128), tetramisole HCL (CYCU-1129), fenvalerate (CYCU-1132), NSC-663284 (CYCU-1138), and BML-267ester (CYCU-1148), were inhibitory to bone mineralization. We also found that alendronate enhanced the level of bone mineralization by inhibiting osteoclast-related genes. To sum up, our research showed that zebrafish may have potential to be a drug-screening and mechanism-analysis platform for bone mineralization.
ARTICLE | doi:10.20944/preprints202108.0304.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: Child nutrition disorders; Vitamin D deficiency rickets; Metabolic bone diseases; Genu valgum; Genu varum; Bone remodelling.
Online: 13 August 2021 (22:44:42 CEST)
Background: Nutritional rickets is still considered as a global health problem especially in low-resource countries and immigrant societies of developed countries. Generalized skeletal deformities including angular knee deformities as genu varum and genu valgum are prominent features of nutritional rickets. Angular knee deformities can cause gait difficulties. However, the true remodelling potential of the healed knee deformities is largely unknown to the pediatric and orthopedic community. Aims: The primary objective of this study protocol is to investigate the natural history of disease in regard to the remodelling potential of angular knee deformities in children and adolescents with healed nutritional rickets. And determine the potential patient- and deformity-related factors that are associated with a favorable deformity remodelling as age and sex of patients and type, severity, laterality of deformities etc. Methods: This will be a prospective observational analytical cohort natural history of disease study. A minimum of at least 140 knees with healed nutritional rickets and angular knee deformities will be observed at regular three-monthly intervals over a period of at least one year. We will report two outcome variables namely; clinical and radiological tibio-femoral angle. And independent patient and deformity-related variables as age, sex, deformity type, severity and laterality. Inferential statistics namely bivariate and multivariate analysis will be employed accordingly to identify the relation between outcome variables and the different independent variables. Ethics and dissemination: This protocol study has been approved by the institutional research ethics committee. Results will be presented at conferences and submitted to relevant international and society publications. Authors will also communicate the results to their scholarly networks and post them on scholarly networking sites. Conclusions: This study has the potential for improving the decision-making process as to which patients deserve conservative treatment and which deserve surgical deformity correction. Results are expected to have an impact on the clinical practice of pediatricians, orthopedic surgeons and family physicians alike.
ARTICLE | doi:10.20944/preprints201908.0143.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: acid-etching; micro-rough; bone regeneration; sub-micro-rough; bone integration; osseointegration; dental implants; orthopedic implants
Online: 12 August 2019 (12:35:48 CEST)
Titanium micro-scale topography results in excellent osteoconductivity and bone-implant integration. However, the biological effects of sub-micron topography are unknown. We compared osteoblastic phenotypes and in vivo bone and implant integration abilities between titanium surfaces with micro- (1–5 µm) and sub-micro-scale (0.1–0.5 µm) topographies and machined titanium. Average roughness was 12.5 ± 0.65 nm, 123 ± 6.15 nm, and 24 ± 1.2 nm for machined, micro-rough, and sub-micro-rough surfaces, respectively. The micro-rough surface showed the fewest cells attaching during the initial stage and the lowest proliferation. Calcium deposition and expression of osteoblastic genes were highest on the sub-micro-rough surface and lowest on the machined surface. Bone-to-implant integration was strongest for the micro-rough surface, consistent with it having the greatest ability to retain cells in vitro. Thus, the biological effects of titanium surfaces are not necessarily proportional to the degree of roughness in osteoblastic cultures or in vivo. Sub-micro-rough titanium ameliorates the disadvantage of micro-rough titanium by restoring cell attachment and proliferation and enhances the rate of osteoblastic differentiation over that of micro-rough titanium; however, bone integration and the ability to retain cells are compromised due to its lower interfacial mechanical locking compared to that of micro-rough titanium.
REVIEW | doi:10.20944/preprints201908.0088.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: skeletal metastases of unknown primary; SMUP; bone metastases; unknown primary tumor; bisphosphonates; bone markers; tumor microenvironment
Online: 7 August 2019 (03:57:55 CEST)
Skeletal metastases of unknown primary (SMUP) represent a clinical challenge dealing with patients diagnosed with bone metastases. The management have improved significantly in the past years, however fraught with lack of evidences, approach to these patients held out hope for more systematic and tailored treatment—and some patients can achieve impressive gains. Nevertheless, in real-life practice the outlook at the beginning of the take in charge of SMUP is decidedly more somber. An incomplete translational relevance of pathological and clinical data on the mortality and morbidity rate has had unsatisfactory consequences for SMUP patients and their physicians. We examined several approaches to confront the available evidences and highlighted three key points that emerge. The characterization of the SMUP biologic profile is essential to drive clinical decisions, integrating genetic and molecular profile into a multi-step diagnostic work-up. Nonetheless, pragmatic investigation plan and therapy of SMUP cannot follow a single template; it must be adapted to different pathophysiological dynamics and coordinated with efforts of a systematic algorithm and high-quality data derived from statistically powered clinical trials within. This review argues that greater efforts are required to face the unmet need dealing with SMUP patients in oncology. Finally, we provide an original functional network analysis, identifying novel therapeutic targets.
ARTICLE | doi:10.20944/preprints202310.0965.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: Diabetic foot; Severe disease; Antibiotic bone cement; Lateral bone repositioning; Lower limb function; Dorsalis pedis artery hemodynamics
Online: 16 October 2023 (15:42:17 CEST)
Objective: To evaluate the clinical efficacy of antibiotic bone cement plus lateral bone repositioning for severe diabetic foot and its impact on wound healing rate. Methods: Sixty patients with hemodialysis anemia admitted to the endocrinology department of our hospital from July 2020 to July 2021 were included and randomly assigned to receive antibiotic bone cement plus lateral bone repositioning (observation group) or vacuum sealing drainage (VSD) (control group). Outcome measures included skin temperature of the affected limb, ankle-brachial index, sensory threshold, foot wound healing, dorsalis pedis artery hemodynamics, lower limb function and clinical efficacy. Results: Antibiotic bone cement plus lateral bone repositioning resulted in significantly higher treatment efficiency and transcutaneous partial pressure of oxygen, smaller wound, and lower trauma pH versus VSD, suggesting that antibiotic bone cement plus lateral bone repositioning contributes to potentiating the treatment efficacy and reducing the foot ulcer trauma, thereby facilitating rapid recovery. Patients given antibiotic bone cement plus lateral bone repositioning had larger vascular internal diameter and blood flow and better sensory conduction velocity of the common peroneal nerve and the motor conduction velocity of the tibial nerve versus those given VSD, indicating its vascular and neurological benefits. Conclusion: Antibiotic bone cement plus lateral bone repositioning enhances the treatment efficiency, boosts trauma healing, and promotes postoperative functional recovery of patients.
ARTICLE | doi:10.20944/preprints201811.0212.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: plant polyphenol; EGCG; gelatin; bone formation; congenital bone defect; dedifferentiated fat cell; adipose-derived stem cell; scaffold
Online: 8 November 2018 (11:34:11 CET)
Cost-effective and functionalized scaffolds are in high demand for stem-cell-based regenerative medicine to treat refractory bone defects in craniofacial abnormalities and injuries. One potential strategy is to utilize pharmacological and cost-effective plant polyphenols and biocompatible proteins, such as gelatin. Nevertheless, the use of chemically modified proteins with plant polyphenols in this strategy has not been standardized. Here, we demonstrated that gelatin chemically modified with epigallocatechin gallate (EGCG), the major catechin isolated from green tea, can be a useful material for dedifferentiated fat cells and adipose-derived stem cells and can induce bone regeneration in a rat congenial cleft-jaw model in vivo. Vacuum-heated gelatin sponge modified with EGCG (vhEGCG-GS) induced superior osteogenesis from these two cell types compared with vacuum-heated gelatin sponge (vhGS). The EGCG-modification converted the water wettability of vhGS to a hydrophilic property (contact angle: 110° to 3.8°) and the zeta potential to a negative surface charge; the modification enhanced the cell adhesion property and promoted calcium phosphate precipitation. These results suggest that the EGCG-modification with chemical synthesis can be a useful platform to modify the physicochemical property of gelatin. This alteration is likely to provide a preferable microenvironment for multipotent progenitor cells, inducing superior bone formation in vivo.
REVIEW | doi:10.20944/preprints202311.1884.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Bioceramics; 3Dprinting; Bone tissue engineering; Scaffold fabrication
Online: 29 November 2023 (10:51:22 CET)
3D Printing (3DP) technology has revolutionized the field of the use of bioceramics for maxillofacial and periodontal applications, offering unprecedented control over the shape, size, and structure of bioceramic implants. In addition, bioceramics have become attractive materials for these applications due to their biocompatibility, biostability, and favorable mechanical properties. However, despite their advantages, bioceramic implants are still associated with inferior biological performance issues after implantation, such as slow osseointegration, inadequate tissue response, and increased risk of implant failure. To address these challenges, researchers have been developing strategies to improve the biological performance of 3D printed bioceramic implants. The purpose of this review is to provide an overview of 3DP techniques and strategies for bioceramic materials designed for bone regeneration. The review also addresses the use and incorporation of active biomolecules in 3D printed bioceramic constructs to stimulate bone regeneration. By controlling the surface roughness, and chemical composition of the implant, the construct can be tailored to promote osseointegration and reduce the risk of adverse tissue reactions. Additionally, growth factors, such as bone morphogenic proteins (rhBMP-2) and pharmacologic agent (dipyridamole), can be incorporated to promote the growth of new bone tissue. Incorporating porosity into bioceramic constructs can improve bone tissue formation and the overall biological response of the implant. As such, by employing surface modification, combining with other materials, and incorporation of 3DP workflow can lead to better patient healing outcomes.
ARTICLE | doi:10.20944/preprints202311.1803.v1
Subject: Medicine And Pharmacology, Endocrinology And Metabolism Keywords: Isoflavones; Bone Density; Osteoporosis; Climacterium; Estrogen receptors.
Online: 28 November 2023 (10:02:32 CET)
The phytonutraceutical Ormona® is a product composed of: purified oil of Bixa orellana Linné; dry extract of Myrciaria dubia McVaugh; dry extract of Trifolium pratense L. and dry extract of Euterpe oleracea Mart. obtained using Evolve® technology. This study evaluated the effects of Ormona® on Wistar rats affected by ovariectomy-induced osteoporosis. Pre-treatment was conducted for 15 days before surgery and continued for a further 45 days after the surgical procedure. The experimental design consisted of 5 groups (n=5): OVW: treated with distilled water (1 mL/ kg, p.o); ADS: alendronate sodium (4 mg/ kg p.o); EST: conjugated estrogen (2 ug/ kg, p.o); ORM: Ormona® (20 mg/kg, p.o); ORM + EST: Ormona® (20 mg/kg + conjugated estrogen 2 ug/ kg, p.o. Biochemical and hormonal parameters, along with bone histopathology and trabecular and femoral diaphysis size, were evaluated through Scanning Electron Microscopy (SEM) and bone calcium quantification by atomic absorption spectrophotometry. The results show that ovariectomy caused bone alterations such as loss of femoral microarchitecture, decreased bone homeostasis parameters, and changes in the lipid profile. Estrogen supplementation reduced parameters such as cholesterol, LDL, and Ca2+ concentration. However, Ormona® showed higher serum estradiol levels (p< 0.01), effects on the lipid profile, including parameters that estrogen replacement and alendronate sodium did not affect, with an increase in HDL, and positive modulation of bone metabolism, increasing osteocytes and the presence of osteoblasts. Ormona®, therefore, produced better results than the groups treated with estrogen and alendronate sodium.
REVIEW | doi:10.20944/preprints202311.1701.v1
Subject: Chemistry And Materials Science, Ceramics And Composites Keywords: hydroxyapatite; bone grafting; nanoparticles; immune response; mitochondria
Online: 28 November 2023 (06:56:44 CET)
Abstract: The centrepiece of this analytical review is the metabolism of hydroxyapatite in its natural, bone, and synthetic forms, where the mitochondria-mediated mechanism may serve as the leading mechanism. The possibility that osteoblast mitochondria play an important role in the initial stages of bone mineralisation is discussed. Furthermore, the paper highlights the key role of mitochondria in the metabolism of synthetic hydroxyapatite.Differences between the results of in vivo and in vitro studies using synthetic hydroxyapatite of different morphologies are also detailed. It is noted that long-term infiltration with immune cells and in vivo studies are necessary to adequately evaluate hydroxyapatite as a bone-plastic material.Particular attention is given to the interaction of hydroxyapatite with immune cells and its ability to affect the ribosomes and mitochondria of cells. Due to its mechanical properties, scalability and potential use for the treatment of extensive bone defects of tumor origin, hydroxyapatite is a promising material.This study also highlights the importance of further development of in vitro research methods in the context of their biomimeticity. Overall, this work offers a theoretical direction for future studies of hydroxyapatite as a bone grafting material and emphasises the value of in vivo studies.
ARTICLE | doi:10.20944/preprints202311.0195.v1
Subject: Biology And Life Sciences, Other Keywords: biological profile; radiology; bone loss; forensic anthropology
Online: 3 November 2023 (11:14:46 CET)
Estimating age at death is essential to establish a biological profile from human skeletal remains in both forensic and archeological settings. Imaging studies of skeletal age changes in adults have described metamorphosis of trabecular bone structure and bone loss in the proximal femur , as well as changes in morphology during different stages of life. This study aims to assess the utility of a digital representation of conventional X-ray films of the proximal femur for the estimation of age at death in a sample of 91 adult individuals (47 females and 44 males) of the Coimbra Identified Skeletal Collection. The proposed approach showed a root mean squared error (RMSE) of 17.32 years (and mean absolute error of 13.47 years) for females and an RMSE of 14.06 years (mean absolute error of 11.08 years) for males. The main advantage of this approach is the consistency in the feature detection and extraction, as X-ray images projected on the femora space will always produce the same set features to be analyzed for age estimation while more traditional methods rely heavily on operator experience which can lead to inconsistent age estimates among experts.
REVIEW | doi:10.20944/preprints202310.1236.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: cadmium; bone density; cigarette; melatonin; smoking; osteoblast
Online: 19 October 2023 (10:07:32 CEST)
Cadmium, an environmental toxin, is associated with a range of adverse health effects due to increased Reactive Oxygen Species production, including decreased bone mineral density and osteoporosis. Notably, cadmium is found at concentrations 4-5x higher in the blood of smokers versus non-smokers. Experiments performed in human cancer cells indicate that melatonin may directly protect against cadmium-induced tissue damage via regulation of mitochondrial activity. Further, recent evidence has demonstrated that melatonin can improve bone health for individuals with osteoporosis and partially protect against cadmium-associated inhibition of bone repair. Here we review this data and propose supplementation with melatonin as a strategy to protect against the negative impacts of cadmium exposure on bone mineral density within individuals regularly exposed to cadmium via cigarette smoking.
ARTICLE | doi:10.20944/preprints202308.0457.v2
Subject: Medicine And Pharmacology, Endocrinology And Metabolism Keywords: bone density; DXA; PTX; P1NP; prunes; women
Online: 31 August 2023 (09:03:01 CEST)
Consumption of prunes has been shown to slow bone loss after menopause in American women but there is no data on its effects in Asian women. 135 postmenopausal Korean women with osteopenia were randomized to 100g/day of prunes or no prunes with 600U vitamin D and 800mg of calcium for 12 months. Bone density was measured at baseline and 12 months in the lumbar spine, both hips and the L forearm. Serum levels of CTX and P1NP and vitamin D calcium and phosphate were measured at baseline, 6 and 12 months. PTH was measured at baseline if vitamin D was low Four women dropped out of each group over the 12 months. There was no difference between groups in blood measures or bone density in any region over the 12 month trial., In conclusion 100g/day of prunes has no effect in Korean woman on bone density or bone markers.
REVIEW | doi:10.20944/preprints202308.0750.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: bone conduction implants; middle ear implant; review
Online: 9 August 2023 (10:29:01 CEST)
This review provides a comprehensive overview of two major advancements in hearing loss treatment: the middle ear implant (MEI) and bone conduction implants (BCIs). MEI, surgically inserted in the middle ear, directly stimulate the ossicles, and are primarily employed to treat sensorineural, conductive, or mixed hearing losses. BCIs work via bone conduction, bypassing the outer and middle ear to deliver sound vibrations to the inner ear, beneficial especially for conductive or mixed hearing losses and single-sided deafness. The decision to opt for these devices is a multifaceted process, considering audiological criteria, surgical feasibility, and patient expectations. The review also details the portfolio of available devices, their functioning, and audiological usage indications. While both MEI and BCIs prove beneficial for patients, the review emphasizes the need for careful preoperative planning and counselling, considering factors such as potential complications, surgical challenges, and patient suitability. Overall, the two types of implants, despite their individual complexities, provide an effective alternative to traditional hearing aids, offering a path to improved sound clarity and quality for patients with various types of hearing loss.
ARTICLE | doi:10.20944/preprints202306.2198.v1
Subject: Medicine And Pharmacology, Clinical Medicine Keywords: dalbavancin; bone cement; polymethylmethacrylate; elution; biofilm; vancomycin
Online: 30 June 2023 (14:38:03 CEST)
Based on previous studies of our group in which we demonstrated that dalbavancin loaded in bone cement had good elution capacity for the treatment of biofilm-related periprosthetic infections, we now assess the anti-biofilm activity of dalbavancin and compare it with that of vancomycin up to a 3-month period. We performed an in vitro model based on calculation of percentage reduction of log cfu/ml counts of sonicated steel discs contaminated with Staphylococci and further exposed to bone cement discs loaded with 2.5% or 5% vancomycin and dalbavancin at each study period (24 hours, 48 hours, 1 week, 2 weeks, 6 weeks, 3 months). In addition, we tested the anti-biofilm activity of eluted vancomycin and dalbavancin at each study period based on a 96-well plate model assessing percentage reduction of metabolic activity. Overall, dalbavancin showed a significant concentration decrease from 2 weeks of incubation and maintain its anti-biofilm activity up to 3 months, whereas, despite vancomycin showed a significant decrease at 1w and then it gradually increased, its anti-biofilm activity was significantly lower. Dalbavancin percentage reduction cfu/ml counts were higher than those of vancomycin, both at 2.5% and 5% concentrations. Reduction of log cfu/ml counts were higher for S. epidermidis than for S. aureus, being more notable for 5% dalbavancin at month 3. In addition, percentage reduction of metabolic activity also decreased at 3 months in 5% dalbavancin and 5% vancomycin, being more notable in the last.
REVIEW | doi:10.20944/preprints202212.0115.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: bioactive glass; gelatin; tissue engineering; bone; composite
Online: 7 December 2022 (04:30:39 CET)
Nano/micron-sized bioactive glass (BG) particles are attractive candidates for both soft and hard tissue engineering. They can chemically bond to the host tissues, enhance new tissue formation, activate cell proliferation, stimulate the genetic expression of proteins, and trigger unique an-ti-bacterial, anti-inflammatory, and anti-cancer functionalities. Recently, composites based on bi-opolymers and BG particles have been developed with various state-of-the-art techniques for tis-sue engineering. Gelatin, a semi-synthetic biopolymer, has attracted the attention of researchers because it is derived from the most abundant protein in the body, viz., collagen. It is a polymer that can be dissolved in water and processed to acquire different configurations, such as hydro-gels, fibers, films, scaffolds, etc. Searching "bioactive glass gelatin" in the tile on Scopus renders 80 highly relevant articles published in the last ~10 years, which signifies the importance of such composites. First, this review addresses the basic concepts of soft and hard tissue engineering, in-cluding the healing mechanisms and limitations ahead. Then, current knowledge on gelatin/BG composites including composition, processing and properties is summarized and discussed both for soft and hard tissue applications. This review explores physical, chemical and mechanical features and ion-release effects of such composites concerning osteogenic and angiogenic respons-es in vivo and in vitro. Additionally, recent developments of BG/gelatin composites using 3D/4D printing for tissue engineering are presented. Finally, the perspectives and current challenges in developing desirable composites for the regeneration of different tissues are outlined.
ARTICLE | doi:10.20944/preprints202212.0074.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: tissue engineering; bone; laser; femtosecond; patterning; direct
Online: 5 December 2022 (10:26:46 CET)
Laser patterning of implant materials for bone tissue engineering purposes has shown to be a promising technique to control cell properties such as adhesion or differentiation, resulting in an enhanced osteointegration. However, the perspective of patterning the bone tissue side interface to generate microstructure effects has never been investigated. In the present study, three different laser-generated patterns were machined on the bone surface with the aim to identify the best surface morphology compatible with osteogenic-related cells recolonization. The laser patterned bone tissue was characterized by electron scanning microscopy and confocal microscopy in order to obtain a comprehensive picture of the bone surface morphology. Cortical bone patterning impact upon cell compatibility and cytoskeleton rearrangement to the patterned surfaces was performed with Stromal Cells from Apical Papilla (SCAPs). Results indicated that laser machining had no detrimental effect upon consecutively seeded cells metabolism. Orientation assays revealed that surface patterning characterized by larger hatch distances was correlated with a higher cell cytoskeletal conformation to the laser-machined patterns. For the first time, to our knowledge, bone is considered and assessed here as a potentially engineered-improvable biological interface. Further studies shall focus on in vivo implications of this direct patterning.
ARTICLE | doi:10.20944/preprints202103.0441.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: GBR; bone graft; DDMM; fibroblast; collagen fiber
Online: 17 March 2021 (13:19:38 CET)
Mandibular critical size defect (CSD) due to pathological conditions, trauma, and congenital disease can not heal spontaneously and predominantly filled with fibrous tissue. Therefore, a Guided Bone Regeneration (GBR) combined with bone grafting can be performed. The researchers considered using Demineralized Dentin Material Membrane (DDMM) from bovine dentine as an alternative GBR. This study aimed to determine the amount of fibroblast and collagen density after DDMM and bone graft implantation on CSD. Thirty-six Rattus norvegicus rats were used as samples. Mandibular bone defect 5x5 mm was made, then filled with bone graft and covered with Bovine Pericardium Collagen Membrane (BPCM) in the control group and DDMM in the treatment group. Six samples were sacrificed on 7, 14, and 21 days post-surgical for histology examination. There were no significant differences in the amount of fibroblast and collagen density (p-value > 0,05). The amount of fibroblast is lower and the collagen density is higher in treatment group. DDMM has microporosity to prevent connective tissue ingrowth and dentine tubules to allow growth factors release. DDMM and bone graft implantation can reduce the amount of fibroblasts and increase collagen density of CSD which potentially being used as a CSD alternative treatment for bone regeneration.
Subject: Engineering, Electrical And Electronic Engineering Keywords: dentary bone conduction; photoelectric conversion; auditory ossicles
Online: 5 July 2020 (06:36:57 CEST)
Using the headphone jack of a mobile phone, the proposed device connects mobile music playback through a customized red laser pointer that is cascaded to batteries and the 3.5-mm stereo plug. The red laser pointer flashes according to the frequency of the music currently playing on the mobile phone. The self-made laser pointer which wavelength is 630–650 nm and maximum output is 5 mw and it will light up when the smart phone’s music starts playing at a music frequency matching the light frequency. The frequency signal of the light received by a solar panel is converted to an electrical analog signal, and the analog current signal is amplified through the energy conversion panel and then output to the direct current motor. The motor shaft does not rotate under a small current, but rather only slightly vibrates according to the magnitude of the currents’ analog frequency. Through gripping the motor shaft with teeth, users can transmit audio to the auditory ossicles (i.e., malleus, incus, and stapes) through the dentary bones. After receiving a music signal, the auditory ossicles enable people with congenital or acquired hearing loss to access external audio.
ARTICLE | doi:10.20944/preprints202005.0165.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Bone; 3D Printing; halloysite; PLA Surface Functionalization
Online: 9 May 2020 (11:39:54 CEST)
Three-dimensional (3D) printing techniques have received considerable focus in the area of bone engineering due to its precise control in the fabrication of complex structures with customizable shapes, internal and external architectures, mechanical strength, and bioactivity. In this study, we design a new composition biomaterial consisting of polylactic acid (PLA), and halloysite nanotubes (HNTs) loaded with zinc nanoparticles (PLA+H+Zn). The hydrophobic surface of the 3D printed scaffold was coated with two layers of fetal bovine serum (FBS) on the sides and one layer of NaOH in the middle. Additionally, a layer of gentamicin was coated on the outermost layer against bacterial infection. Scaffolds were cultured in standard cell culture medium without the addition of osteogenic medium. This surface modification strategy improved material hydrophilicity and enhanced cell adhesion. Pre-osteoblasts cultured on these scaffolds differentiated into osteoblasts and proceeded to produce a type I collagen matrix and subsequent calcium deposition. 3D printed scaffolds formed from this composition possessed high mechanical strength and showed an osteoinductive potential. Furthermore, the external coating of antibiotics not only preserved the previous osteogenic properties of the 3D scaffold but also significantly reduced bacterial growth. Our surface modification model enabled the fabrication of a material surface that was hydrophilic and antibacterial, simultaneously, with an osteogenic property. The designed PLA+H+Zn may be a viable candidate for the fabrication of customized bone implants.
REVIEW | doi:10.20944/preprints201802.0051.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: metals; dental regeneration; bioactivity; tissue regeneration; bone
Online: 6 February 2018 (05:25:46 CET)
The regeneration of bone tissue is a main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based on natural (allo- and xenografts) and synthetic origins (alloplastic materials) are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, while it should be resorbed even in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated and it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also on osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between the formation of new bone tissue and material degradation has not been found until now. The addition of different substances such as collagen or growth factors and also of different cell types have already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are differently used as basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designated for bone regeneration with the aim to give an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.
ARTICLE | doi:10.20944/preprints202012.0541.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: 3D printing; biomimetic; poly (lactic acid); spheroids; bone repair; 3D printed scaffold; bone morphogenetic protein 2; biomimetic apatite.
Online: 21 December 2020 (16:48:39 CET)
This study aimed to assess the response of 3D printed PLA scaffolds biomimetically coated with apatite on human primary osteoblast spheroids and evaluate the biological response to its association with Bone Morphogenetic Protein 2 (rhBMP-2) in rat calvaria. PLA scaffolds were produced via 3D printing, soaked in simulated body fluid (SBF) solution, and characterized by physical-chemical, morphological, and mechanical properties. The in vitro biological response was assessed with human primary osteoblast (HOb) spheroids. The in vivo analysis was conducted through the implantation of 3D printed PLA scaffolds either alone, covered by apatite (PLA-CaP) or PLA-CaP loaded with rhBMP-2 (PLA-CaP+rhBMP-2) on critical-sized defects (8 mm) of rat calvaria. Increased cell adhesion and in vitro release of growth factors (PDGF, bFGF, VEGF) was observed for PLA-CaP scaffolds when pre-treated with FBS. PLA-CaP+BMP2 presented higher values of newly formed bone (NFB) than other groups at all experimental periods (p<0.05), attaining 44.85% of NFB after 6 months. These findings indicate that functionalization of PLA scaffolds with biomimetic apatite can improve its biological properties in the presence of complex biological media. Its association with BMP2 may enhance bone repair, suggesting this strategy as a promising candidate for bone tissue engineering.
REVIEW | doi:10.20944/preprints202311.1996.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Hydrogel Microparticles; Microgels; Bone Tissue Engineering; Bone Regeneration; Cell Delivery; Bioactive Factor Delivery; HMP-based scaffolds; HMP incorporated scaffolds
Online: 30 November 2023 (14:15:08 CET)
The loss or dysfunction of skeletal tissue often necessitates surgical intervention, particularly in cases involving trauma, tumors, or abnormal development leading to critical-sized defects. Despite autografts being considered the gold standard for bone grafts, their limitations and complications prompt the exploration of alternative approaches for bone repair and regeneration. Current advancements in bone tissue engineering have led to innovative strategies aiming to regenerate injured bone structures, providing viable alternatives to traditional autografts or allografts. Among these strategies, Hydrogel Microparticles (HMPs) have emerged as promising scaffolds due to their notable characteristics, including high porosity and mechanical tunability. HMPs play an important role in facilitating vasculature formation, mineral deposition, and overall bone tissue regeneration. HMPs, fabricated through various techniques, exhibit versatility in functions such as drug and cell delivery, structural scaffolding, and bioinks for 3D printing. In addition, these microgels can be injected for minimally invasive delivery and can display modular properties with different designs and configurations. This review exclusively focuses on the advancements in HMPs for bone regeneration, delving into synthesis and functionalization techniques while highlighting their diverse applications documented in the literature. Our aim is to shed light on the unique benefits and potential of HMPs in the intricate field of engineering bone tissue.
CASE REPORT | doi:10.20944/preprints202002.0028.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Geometry optimization of scaffolds; allograft; block bone grafts; custom made bone; design techniques for scaffold; precision and translational medicine
Online: 3 February 2020 (09:46:05 CET)
Background: The aim of the present investigation was to evaluate the clinical success of horizontal ridge augmentation in the severely atrophic maxilla (Cawood and Howell class IV) using freeze-dried custom made bone harvested from cadaver donors tibial hemiplateau and to analyze the marginal bone level gain prior dental implants placement at 9 months after bone grafting and before prosthetic rehabilitation. Methods: A 52-year-old woman received custom made bone grafts. Patient underwent CT scans 2 weeks prior and 9 months after surgery for graft volume and density analysis. Results: The clinical and radiographic bone observations showed a very low rate of resorption after bone graft and implant placement. Conclusions: The custom-made allograft material was a highly effective modality for restoring the alveolar horizontal ridge, resulting in this way to reduce the need to obtain autogenous bone from a secondary site with predictable procedure. Further studies are needed to investigate its behavior at longer time points.
INTERESTING IMAGES | doi:10.20944/preprints202310.0924.v1
Subject: Medicine And Pharmacology, Clinical Medicine Keywords: bone scan; 99mTc-HDP; cardiac amyloidosis; iron overload
Online: 16 October 2023 (08:19:35 CEST)
In this presented case, a 77 years old woman suffering from ongoing knee pain underwent a bone scan using 99mTc-hydroxydiphosphonate (HDP) in suspicious for bone infection. An incidental finding from this scan revealed diffuse cardiac uptake, necessitating further diagnostic procedures to exclude the possibility of cardiac amyloidosis. In the subsequent 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scan and SPECT images, no perceptible cardiac uptake was observed at all. Upon retrospective review of the patient’s medical records, she had received 1000mg of ferric carboxymaltose for iron-deficient anemia, the day before the 99mTc-HDP bone scan. Therefore, it is assumed that the diffuse and temporary cardiac activity was due to the transient iron overload. We present and share this bone scan images in order to avoid possible future misinterpretation of cardiac amyloidosis.
ARTICLE | doi:10.20944/preprints202309.0678.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: bone regeneration; callus tissue; cissus quadrangularis; extracellular vesicles
Online: 12 September 2023 (05:44:18 CEST)
Exosomes are membrane-bound, biologically active nanovesicles of size 30-200 nm produced by many cell types, such as both mammalian and plant cells. They are wrapped in a phospholipid bilayer and play a significant role in intercellular communications. The ease in their isolation and the ability of plant-derived exosome-like nanovesicles (PDEVs) to efficiently deliver bioactive constituents into mammalian cells have made them popular in contemporary research. PDEVs share many characteristics with mammalian EVs (MEVs), including shape, size, surface charge, and consist of bioactive molecules like lipids, proteins, nucleic acids, and tiny metabolites. However, the chemical composition profile of PDEVs and their biogenesis mechanism differ significantly from those of MEVs. They have been widely explored as potential therapeutic agents and are considered as good alternatives to act as a carrier for drug delivery. The present work elucidates the isolation of exosome-like-nanovesicles (henceforth exosomes) from the culture supernatants of an in vitro cultured callus tissue derived from a bone healing plant known for its osteogenic activity, i.e., Cissus quadrangularis. The physical and biological properties of exosomes were successfully studied using different characterization techniques. To assess their therapeutic potential, we studied the internalisation of calcein-AM labeled exosomes by human derived mesenchymal stromal cells (hMSCs). Additionally, we evaluated the potential of exosomes in the migration of cells in a cell scratch assay with hMSCs and their effect on amelioration of oxidative stress was investigated on preosteoblast MC3T3-E1 cells that were pre-treated with these exosomes. Furthermore, we investigated their proliferation and differentiation to osteoblasts like cells with the help of resazurin assay and alkaline phosphatase assay (ALP). The obtained results provide a primary justification for the use of Cissus quadrangularis-derived exosomes as a nanocarrier for drug molecules for various therapeutic bone applications.
ARTICLE | doi:10.20944/preprints202309.0117.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: p53 expression; TP53 mutation; myelodysplasia; myeloblast; bone marrow
Online: 4 September 2023 (07:23:19 CEST)
Background: TP53 alterations have a significant prognostic effect in myeloid neoplasms. Our objective was to investigate the TP53 gene mutation status, p53 protein expression, and their re-lationship in dysplasia-related myeloid neoplasms with varying levels of myeloblast counts. Methods: 76 bone marrow biopsy samples with different blast counts were analyzed. Total and strong (3+) p53 expression was determined. Dual immunohistochemical staining was performed to determine the cell population associated with p53 expression. NGS analysis was performed using the Accel-Amplicon Comprehensive TP53 panel. Results: Both p53 expression and TP53 VAF showed a significant correlation with the myeloblast ratio (p<0.0001), however, p53 expres-sion was present in other cell lineages as well. The VAF value exhibited a significant correlation with p53 expression. A high specificity (0.9800) was observed for TP53 mutation using the ≥10% strong (3+) p53 cut-off value, although the sensitivity (0.4231) was low. Conclusion: Strong (3+) p53 expression using a ≥10% cut-off value accurately predicts TP53 mutation but doesn't reveal the allelic state. The p53 expression is significantly influenced by myeloblast count, and histo-logical interpretation should consider the presence of intermixed non-neoplastic marrow cells with varying physiological p53 expression.
ARTICLE | doi:10.20944/preprints202308.1635.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: Biofilm; silver; bone; nanotechnology; impregnation; bacteria; NDM; scaffold
Online: 23 August 2023 (07:19:07 CEST)
Background: Antibiofilm activity of silver nanoparticles has been extensively investigated in common bacteria. Metallo-β-lactamase producing Gram-negative bacteria are hard-to-treat microorganisms with few therapeutic options, and silver nanoparticles were not evaluated on the biofilm of these bacteria. Objectives: The aim of this study was to evaluate the antibiofilm activity of a bone scaffold impregnated with silver nanoparticles in NDM-producing Gram-negative bacilli. Methods: Bone scaffolds from bovine femur were used for the tests and impregnated with silver nanoparticles (50 nm) by physical adsorption. Silver nitrate minimal inhibitory and bactericidal concentrations (MIC and MBC) were performed on NDM-producing Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Disc diffusion tests for silver nanoparticles susceptibility and quantification of biofilm production on plate and bone with sessile cell count were performed. Results: The MIC results demonstrated that silver nitrate had an antimicrobial effect on all microorganisms, inactivating the growth of isolates from a concentration of 8 µg/mL. MBC results showed that E. coli 16.211 was the only isolate to present MIC different from MBC, with a value of 16 µg/mL. Conclusion: Bone scaffolds impregnated with silver nanoparticles can significantly reduce biofilm, and it can be a strategic material to be used as an implant for different approaches.
ARTICLE | doi:10.20944/preprints202307.1668.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: porcine bone grafts; horizontal ridge augmentation; dental implant
Online: 25 July 2023 (08:29:55 CEST)
The purpose of this study was to evaluate the outcomes of implants placed in horizontally augmented alveolar ridges using porcine bone grafts and to investigate the long-term stability of the porcine bone grafts. A retrospective analysis was conducted on 55 sites that underwent horizontal ridge augmentation using porcine bone grafts and implant placement with a follow-up period longer than 5 years. Furthermore, additional analysis was conducted on 24 sites where porcine bone grafts were used exclusively and implants were placed simultaneously with horizontal ridge augmentation. The mean follow-up period after prosthesis loading was 67.3 months, with a mean marginal bone loss of 0.18 mm at 1 year and a cumulative mean marginal bone loss of 0.37 mm over the entire follow-up period. Of the 55 implants, 2 were lost and 4 did not meet the success criteria, resulting in a survival rate of 96.4% and a success rate of 89.1%. In 24 sites, the mean marginal bone loss was 0.22 mm at 1 year and 0.40 mm at 65.8 months, with 100% survival and success rates. Porcine bone grafts can be successfully used in horizontal ridge augmentation for implant placement in cases of ridges with insufficient horizontal width.
ARTICLE | doi:10.20944/preprints202305.1261.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: biocompatible materials; calcium phosphates; hydrated pastes; bone tissue
Online: 18 May 2023 (03:07:39 CEST)
The injectable hydrated calcium phosphate bone-like paste (hCPP) have been developed with suitable nanoscale characteristics and unindered injection through 23G standard needles. In vitro assays showed the cytocompatibility of hCPP with mesenchymal embryonic C3H10T1/2 cell cultures. The hCPPs were identified to be composed of aggregated nano-sized particles with sphere-like shapes with low crystallinity. The ability of serum proteins (FBS) to adsorb on hCPP particles was also studied. The hCPP demonstrated high protein adsorption capacity, thereby indicating its potential in various biomedical applications. The results of the in vivo assay upon subcutaneous injection in Wistar rats indicated the nontoxicity and biocompatibility of experimental hCPP, as well as the gradual resorption of hCPP, comparable to the period of bone regeneration. The data obtained are of great interest for the development of commercial highly effective osteoplastic materials for bone tissue regeneration and augmentation.
REVIEW | doi:10.20944/preprints202303.0395.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: calvarium; bone; traumatic brain injury; biomechanics; pathology; fracture
Online: 22 March 2023 (10:23:44 CET)
Mild impacts to the head, particularly when repetitive in nature, are increasingly recognized to have a range of significant negative implications for brain health. Much of the ongoing research in the field is focused on the neurological consequences of these injuries, and the relationship between head impacts and long-term neurodegenerative conditions such as chronic traumatic encephalopathy and Alzheimer’s disease. However, our understanding of the complex relationship between applied mechanical force at impact, brain pathophysiology, and neurological function, remains incomplete. Past research has shown that mild head impacts, even below the threshold that results in cranial fracture, induce changes in cranial bone structure and morphology. These structural and physiological changes likely have implications for the transmission of mechanical force into the underlying brain parenchyma. Here, we review this evidence in the context of the current understanding of bone mechanosensitivity and the consequences of traumatic brain injuries or concussions. We postulate that heterogeneity of the calvarium including differing bone thickness due to prior impacts, age, or individual variability, may be a modulator of outcomes following subsequent head impacts. We advocate for greater consideration of cranial responses to head injury in both experimental and computer modeling of impact biomechanics, and raise the hypothesis that calvarial bone thickness represents a novel biomarker of brain injury vulnerability after head trauma.
ARTICLE | doi:10.20944/preprints202212.0195.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: radiomics; machine learning; radiation therapy; bone metastases; prediction
Online: 12 December 2022 (08:22:54 CET)
Background: Painful spinal bone metastases (PSBMs) patients regularly receive palliative radiation therapy (RT) with response rates in about 2 of 3 patients. In this exploratory study, we evaluated the value of machine learning (ML) models based on radiomic, semantic and clinical features to predict complete pain response. Methods: Gross tumour volumes (GTV) and clinical target volumes (CTV) of 261 PSBMs were segmented on planning computed tomography (CT) scans. Radiomic, semantic and clinical features were collected for all patients. Random forest (RFC) and support vector machine (SVM) classifiers were compared using repeated nested cross-validation.Results: The best radiomic classifier was trained on CTV with an area under the receiver-operator curve (AUROC) of 0.62 ± 0.01 (RFC; 95% confidence interval). The semantic model achieved a comparable AUROC of 0.63 ± 0.01 (RFC), significantly below the clinical model (SVM, AUROC: 0.80 ± 0.01); and slightly lower than the spinal instability neoplastic score (SINS; LR, AUROC: 0.65 ± 0.01). A combined model did not improve performance (AUROC: 0,74 ± 0,01).Conclusions: We could demonstrate that radiomic and semantic analyses of planning CTs allowed for limited prediction of therapy response to palliative RT. ML predictions based on established clinical parameters achieved the best results.
REVIEW | doi:10.20944/preprints202208.0071.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: Prostate cancer; radionuclide therapy; bone; PSMA; GRPR; Somatostatin
Online: 3 August 2022 (03:51:17 CEST)
The recent approval of 177Lu PSMA-617 (Pluvicto®) by the United States Food and Drug Administration (FDA) is the culmination of decades of work in advancing the field of targeted radionuclide therapy for metastatic prostate cancer. 177Lu PSMA-617, along with the bone specific radiotherapeutic agent, 223RaCl2, are now commonly used in routine clinical care as a tertiary line of therapy for men with metastatic castrate resistant prostate cancer and for osseus metastatic disease respectively. While these radiopharmaceuticals are changing how metastatic prostate cancer is classified and treated, there is relatively little guidance to the practitioner and patient as to how best utilize these therapies, especially in conjunction with other more well-established regimens including hormonal, immunologic, and chemotherapeutic agents. This review article will go into detail about the mechanism and effectiveness of these radiopharmaceuticals and less well known classes of targeted radionuclide radiopharmaceuticals including alpha emitting prostate specific membrane antigen (PSMA) -, gastrin-releasing peptide receptor (GRPR) -, and somatostatin targeted radionuclide therapeutics. Additionally, a thorough discussion of the clinical approach of these agents is included and required futures studies.
ARTICLE | doi:10.20944/preprints202108.0507.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: vitamin D; osteopenia; prematurity; metabolic bone disease; rickets
Online: 26 August 2021 (11:54:33 CEST)
Appropriate supplementation of vitamin D can affect infections, allergy, and mental and behavioral development. This study aimed to assess the effectiveness of monitored vitamin D supplementation in a population of preterm infants. 109 preterm infants (24 0/7–32 6/7 weeks of gestation) were randomized to receive 500 IU vitamin D standard therapy (n=55; approximately 800-1000 IU from combined sources) or monitored therapy (n=54; with an option of dose modification). 25(OH)D concentrations were measured at birth, 4 weeks of age, and 35, 40, and 52±2 weeks of post-conceptional age (PCA). Vitamin D supplementation was discontinued in 23% of infants subjected to standard treatment due to increased potentially toxic 25(OH)D concentrations (>90 ng/mL) at 40 weeks of PCA. A significantly higher infants’ percentage in the monitored group had safe vitamin D levels (20–80 ng/mL) at 52 weeks of PCA (p=0.017). We observed increased vitamin D levels and abnormal ultrasound findings in five infants. Biochemical markers of vitamin D toxicity were observed in two patients at 52 weeks of PCA in the control group. Inadequate and excessive amounts of vitamin D can lead to serious health problems. Supplementation with 800–1000 IU of vitamin D prevents deficiency and should be monitored to avoid overdose.
ARTICLE | doi:10.20944/preprints202007.0531.v2
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: dietary calcium intake; osteoporosis; fractures; bone mineral density
Online: 14 December 2020 (12:20:21 CET)
A low calcium intake is associated with an increased fracture risk. We assessed the dietary calcium intake in a cohort of Italian individuals evaluated for low bone mineral density (BMD). A 7-day food-frequency questionnaire was administered to 1793 individuals consecutively referred at a Centre of the Italian Society for Osteoporosis, Mineral Metabolism and Skeletal Diseases for low BMD. In 30.3% (544/1793) and 20.9% (374/1793) of subjects the calcium intake was inadequate ( <700 mg/day) and adequate (>1200 mg/day), respectively. Patients with calcium intake <700 mg/day showed a higher prevalence of diabetes mellitus, idiopathic hypercalciuria and food allergy/intolerance (8.1%, 5.1%, 7.2%, respectively) than patients with calcium intake >700 mg/day (5.3%, 3.0%, 4.1%, respectively, p<0.04 for all comparisons), also after adjusting for age, gender and BMI. In 30.3% of fractured subjects the calcium intake was <700 mg/day. In Italy, a low calcium intake is highly prevalent in individuals at risk for low BMD. Importantly, an inadequate calcium intake is highly prevalent even in patients with history of fragility fractures. Only about a fifth of patients at risk for low BMD reported an adequate calcium intake
ARTICLE | doi:10.20944/preprints202011.0210.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: bioactive glass; gelatin; chitosan; 3-Glycidyloxypropyl trimethoxysilane; bone.
Online: 5 November 2020 (10:48:46 CET)
Bioactive glass (BG) represents a promising biomaterial for bone healing; here injectable BG pastes biological properties were improved by 25 wt% gelatin or chitosan, as well as mechanical resistance was enhanced by adding 10 or 20 wt% 3-Glycidyloxypropyl trimethoxysilane (GPTMS) cross-linker. Composites exhibited bioactivity as apatite formation was observed by SEM and XRD after 14 days immersion in SBF; moreover, polymers did not enhance degradability as weight loss was >10% after 30 days in physiological conditions. BG-gelatin-20 wt% GPTMS composites demonstrated the highest compressive strength (4.8±0.5 MPa) in comparison with 100% BG control (1.9±0.1 MPa). Cytocompatibility was demonstrated towards human mesenchymal stem cells (hMSC), osteoblasts progenitors and endothelial cells. The presence of 20 wt% GPTMS conferred antibacterial properties thus inhibiting the joint pathogens Staphylococcus aureus and Staphylococcus epidermidis infection. Finally, hMSC osteogenesis was successfully supported in a 3D model as demonstrated by alkaline phosphatase release and osteogenic genes expression.
ARTICLE | doi:10.20944/preprints202005.0420.v1
Subject: Medicine And Pharmacology, Veterinary Medicine Keywords: Biodentine, MTA, new bone formation; Osteonectin, furcation perforation
Online: 26 May 2020 (05:34:25 CEST)
This study compared the Biodentine (BD) and MTA in repair of furcation perforation (FP) in a dog model in terms of inflammatory cell count and new hard tissue formation through histological and immunohistochemical evaluations. Ninety six teeth in six adult mongrel dogs were divided according to the time of repair into two groups (48 teeth/3 dogs each); immediate and delayed repair of the induced FP. Each group was divided into three subgroups (16 teeth each) according to the evaluation periods; 1, 2, and 3 months. Each subgroup was further subdivided into four subdivisions according to the material used; MTA (6 teeth), Biodentine (6 teeth), negative control (2 teeth) and positive control (2 teeth). In experimental and positive control samples, the teeth were instrumented and obturated then, a FP was performed. The perforations were sealed according to the groups and subdivisions. Histopathology and immunohistochemical analysis using Osteonectin antibodies were performed for assessment of the inflammatory cell count and new hard tissue formation. In all groups and subgroups, there were no significant differences between MTA and BD in the inflammatory cell count and new hard tissue formation (P>0.05). Biodentine can alternate the MTA as a FP repair material.
REVIEW | doi:10.20944/preprints201609.0092.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: PMMA; bone cement; cardiac embolism; cement leakage; viscosity
Online: 26 September 2016 (10:34:26 CEST)
Percutaneous vertebroplasty procedure is of major importance, given the significant increasing aging population and higher number of orthopedic procedures related to vertebral compression fractures. Vertebroplasty is a complex technique involving injection of polymethylmethacrylate (PMMA) into the compressed vertebral body for mechanical stabilization of the fracture. Our understanding and ability to modify these mechanisms through alterations in cement material is rapidly evolving. However, the rate of cardiac complications secondary to PMMA injection and subsequent cement leakage has increased with time. The following review considers the main features of PMMA bone cement on the heart, and the extent of influence of materials on cardiac embolism. Clinically, cement leakage results in life-threatening cardiac injury. The convolution of this outcome through an appropriate balance of complex material properties is highlighted via clinical case report.
ARTICLE | doi:10.20944/preprints201608.0113.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: Growing pains; genu valgum; perinatal factors; bone metabolism
Online: 10 August 2016 (15:20:53 CEST)
The most prevalent musculoskeletal disorder of childhood with unclear aetiology is Growing Pains (GPs). Anatomic deformities and factors that change bone turnover are implicated in GPs pathophysiology. Perinatal risk factors alter the bone metabolism affecting the bone mineral density and content. The aim of our study was to analyze the relationship between GPs, knock knees and perinatal factors. The examined population consisted of 276 children aged 3-7 years. Among them 10 pairs of dizygotic twins were evaluated. The data were collected by using a combination of semi-structured questionnaires, clinical examinations and medical charts of the children and the obstetric history of the mothers. 78 children presented GPs meeting Peterson’s criteria. Genu valgum severity was a significant factor for GPs manifestation and for their increased frequency and intensity. Subsequently, perinatal factors regarding gestational age, Apgar score, head circumference (lower than 33cm) and birth length or weight (smaller than 50 cm and 3000gr, respectively) made a remarkable contribution to the development of GPs. Conversely, antenatal corticosteroid treatment, increased maternal age and maternal smoking during pregnancy were not predictive for the disorder. Our data are potentially supportive for the “bone strength” theory and for the contribution of anatomical disturbances in GPs appearance.
REVIEW | doi:10.20944/preprints202311.1546.v1
Subject: Medicine And Pharmacology, Dietetics And Nutrition Keywords: osteopenia; osteoporosis; nutraceuticals; prevention; lifestyle; bone health; minerals; phytochemicals.
Online: 23 November 2023 (16:10:43 CET)
Osteoporosis is characterized by low bone mass and structural deterioration of bone tissue with increased risk of fracture. The population that is most at risk for primary osteoporosis in-cludes post-menopausal women. Among different approaches, nutraceuticals are increasingly popular in developed countries since can contribute to bone health and can delay the onset of pathological bone loss. Our review covers three main aspects. Firstly, we discuss the current state of the two con-ditions, osteopenia, and osteoporosis. Secondly, we focus on the latest developments in natural Nutraceuticals and their effectiveness in reducing bone loss. Finally, we conduct a Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis to examine the pros and cons of Nutraceuticals assumption. Nutraceuticals hold great promise, but we must address challenges such as regulatory control and experimental evidence to fully realize their potential. Other challenges include identifying the source of raw materials, ensuring the purity of the compound, avoiding contamination or the presence of other active compounds, maintaining product quality, and preventing interactions with other elements or drugs. By addressing these challenges, the scientific community can ensure more reliable indica-tions for the use of Nutraceuticals and help people lead healthier lives.
ARTICLE | doi:10.20944/preprints202311.0318.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: Salicornia europaea; Dicaffeoylquinic acids; Bone loss; Osteoclast; Reactive oxygen
Online: 6 November 2023 (13:45:40 CET)
Osteoporosis, often linked to increased osteoclast activity due to menopause or aging, was the focus. In this study, the inhibitory effects of Salicornia europaea L. (SE) water extract of desalted SE (WSE) were investigated on osteoclast differentiation and bone loss in ovariectomized mice. The findings revealed that WSE effectively inhibited RANKL-induced osteoclast differentiation, as evidenced by TRAP staining, and also suppressed bone resorption and F-actin ring formation in a dose-dependent manner. Gene expressions related to osteoclast differentiation, including NFATc1, TRAP, cathepsin K, and DC-STAMP, were downregulated by WSE. Oral administration of WSE improved bone density and structural parameters in ovariectomized mice. Dicaffeoyl quinic acids (DCQAs) and saponins in WSE were detected, with 3,4-, 3,5-, and 4,5-DCQA isolated and identified. All tested DCQAs, including the aforementioned types, inhibited osteoclast differentiation, bone resorption, and the expression of osteoclast-related genes. Furthermore, WSE and DCQAs reduced ROS production mediated by RANKL. These results indicate the potential of WSE and its components, DCQA, as preventive or therapeutic agents against osteoporosis and related conditions.
ARTICLE | doi:10.20944/preprints202310.1263.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: calcium sulfate; bone cement; terbium; solubility; calcium phosphate layer
Online: 19 October 2023 (12:38:50 CEST)
Calcium sulfate (CS) materials containing terbium ions at 0, 1.0, or 2.0 mol.% were obtained by mechanochemical synthesis. According to X-ray diffraction data, the powder materials are characterized by the presence of a CaSO4×0.5H2O phase, while Tb3+ is incorporated into the lattice at ≤1.0 mol.%. Specific surface area enlarged from 2.1 to 22.5 m2/g as crystallite size decreased from 68 to 31 nm and the Tb3+ concentration increased up to 1.0 mol.%. Thermal analysis showed that terbium slightly raises the temperature of CaSO4×2H2O-to-CaSO4 transition. The presence of Tb3+ did not affect the solubility of the CS cements. Furthermore, after 7 days of soaking of the materials in a simulated body fluid, a calcium phosphate layer formed corresponding to a hydroxyapatite phase, in contrast to the pure cements. Luminescent properties were studied by excitation at 276 nm. The recorded emission peaks of the CS materials indicated that the luminescence of the samples is green and blue, with the most intense luminescence observed for samples containing 1.0 mol.% Tb3+. The developed materials can find applications in medicine as bioimplants for the regeneration and restoration of bone tissue with a possibility of noninvasive monitoring of the bone restoration process.
ARTICLE | doi:10.20944/preprints202309.2073.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: horse; castration; steroid hormones; cartilage; bone; in vivo metabolism
Online: 29 September 2023 (05:25:34 CEST)
Castration of stallions is traditionally performed after puberty around the age of 2 years old. No studies have focused on the effects of early castration on osteoarticular metabolism. Thus, we sought to compare early castration (3 days after birth) with traditional castration (18 months of age) in horses. Testosterone and estradiol levels were monitored from birth to 33 months in these two groups. We quantified the levels of biomarkers of cartilage and bone anabolism (CPII and N-MID) and catabolism (CTX-I and CTX-II), of osteoarthritis (HA and COMP) and inflammation (IL-6 and PGE2). We revealed a lack of parallelism between testosterone and estradiol syntheses after birth and during puberty in both groups. An extra-gonadal synthesis of steroids was observed around the 28 month-mark, regardless of the castration age. We found the expression of estrogen receptor (ESR1) in cartilage and bone, whereas androgen receptor (AR) expression appeared to be restricted to bone. Nevertheless, with regards to osteoarticular metabolism, steroid hormone deprivation resulting from early castration showed no discernable impact on the levels of biomarkers related to bone and cartilage metabolism, nor on those associated with OA and inflammation. Consequently, our research demonstrated that early castration does not disrupt bone and cartilage homeostasis.
COMMUNICATION | doi:10.20944/preprints202309.1750.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Bone remodelling; Mg implants; In-silico study; stress-shielding
Online: 26 September 2023 (10:15:27 CEST)
The type of implant at the fracture site has effects not only from biological perspective but also from mechanical perspective in fracture healing. Biodegradable implants such as magnesium (Mg) based alloys have shown faster secondary bone healing properties as compared to bioinert implants such as titanium (Ti). The general reasoning behind this is the benefit of Mg from biocompatibility perspectives. We study the effect of Ti and Mg as base materials for implants with their different mechanical properties. The focus of our work is on the displacements at the fracture site of the tibia and their influence on the stimulus for bone healing. We have found that in comparison to Ti, Mg implants have minimal stress shielding problem, only which led to better mechanical stimulus at the fracture site.
ARTICLE | doi:10.20944/preprints202306.0997.v1
Subject: Medicine And Pharmacology, Clinical Medicine Keywords: Guided Bone Regeneration; dental implant; PLACL; resorbable bilayer membrane
Online: 14 June 2023 (07:10:22 CEST)
Insufficient oral ridge tissue presents a challenge in the treatment of dental implants. One method to enhance alveolar crest dimensions is guided bone regeneration (GBR); however, existing membranes have certain limitations. To address this issue, we aimed to compare the effectiveness of a resorbable bilayer membrane composed of poly(l-lactic acid) and poly(-caprolactone) （PLACL）with that of a collagen membrane（COL） in a rat GBR model. The rat calvaria was used as an experimental model by placing a plastic cylinder. Forty male Fisher rats underwent surgery, and micro-computed tomography and histomorphometric analyses were performed to assess bone regeneration. The results showed that bone regeneration was similar across all the groups. However, after 24 weeks, the PLACL membrane demonstrated significant resilience, occasional partial degradation, and intermittent air bubble formation. This extended preservation of the barrier effect has great potential to facilitate optimal bone regeneration. In conclusion, this study shows that the PLACL membrane is a promising alternative to GBR. By providing a durable barrier and supporting bone regeneration over an extended period, this resorbable bilayer membrane may address the limitations of the current membranes. Further studies and clinical trials are warranted to validate the efficacy and safety of this drug in humans.