A recent study published in Nature Medicine (Mautner et al., Nat Med 2023 Nov 2. doi: 10.1038/s41591-023-02632-w. Epub ahead of print) reported findings regarding a four-arm parallel, multicenter, single-blind, randomized, controlled clinical trial with 480 patients, aimed at comparing the therapeutic effectiveness of orthobiologic interventions against corticosteroid injections for the treatment of knee osteoarthritis (OA). The study concluded that, one-year post-treatment, all orthobiologic therapies examined were equivalent in effectiveness to each other and to corticosteroid injections. While we commend the scope and methodological rigor of the trial, the publication could be enhanced by a more comprehensive presentation of data to support the conclusions drawn. Particularly, the omission of baseline data for primary outcomes, the missing context to evaluate absolute values, the lack of discussion regarding interindividual variability, and the unexpectedly favorable results for corticosteroids that contrast the established literature, are areas that merit additional examination and insight. Here we aim to highlight these points for consideration, and advocate for the release of supplementary data to facilitate a comprehensive understanding and utilization of this rich dataset.

Background: Conclusions of meta-analyses of clinical studies may substantially influence opinions of perspective patients and stakeholders in health care. Nineteen meta-analyses of clinical studies on the management of primary knee osteoarthritis (pkOA) with stem cells, published between January 2020 and July 2021, came to inconsistent conclusions regarding the efficacy of this treatment modality. It is possible that a separate meta-analysis based on an independent, systematic assessment of clinical studies on the management of pkOA with stem cells may reach a different conclusion. Methods: PubMed, Web of Science and the Cochrane library were systematically searched for clinical studies and meta-analyses of clinical studies on the management of pkOA with stem cells. All clinical studies and meta-analyses identified were evaluated in detail, as were all sub-analyses included in the meta-analyses. Results: The inconsistent conclusions regarding the efficacy of treating pkOA with stem cells in the 19 assessed meta-analyses were most probably based on substantial differences in literature search strategies among different authors, misconceptions about meta-analyses themselves, and misconceptions about the biology of stem cells. An independent, systematic review of the literature yielded a total of 183 studies, of which 33 were randomized clinical trials, including a total of 6860 patients with pkOA. However, it was not possible to perform a scientifically sound meta-analysis. Conclusion: Clinicians should interpret the results of the 19 assessed meta-analyses of clinical studies on the management of pkOA with stem cells with caution, and should be cautious of the conclusions drawn therein. Clinicians and researchers should strive to participate in FDA and/or EMA reviewed and approved clinical trials to provide clinically and statistically valid efficacy.

Current clinical treatment options for symptomatic, partial-thickness rotator cuff tear (sPTRCT) offer only limited potential for true tissue healing and improvement of clinical results. In animal models, injections of adult stem cells isolated from adipose tissue into tendon injuries evidenced histological regeneration of tendon tissue. However, it is unclear whether such beneficial effects could also be observed in a human tendon treated with fresh, uncultured, autologous, adipose derived regenerative cells (UA-ADRCs). A specific challenge in this regard is that UA-ADRCs cannot be labeled and, thus, not unequivocally identified in the host tissue. Therefore, histological regeneration of injured human tendons after injection of UA-ADRCs must be assessed using comprehensive, immunohistochemical and microscopic analysis of biopsies taken from the treated tendon a few weeks after injection of UA-ADRCs.

It has become practically impossible to survey the literature on cells derived from adipose tissue with the aim to apply them in regenerative medicine. The aim of this review is to provide a jump start to understanding the potential of UA-ADRCs (uncultured, unmodified, fresh, autologous adipose derived regenerative cells isolated at the point of care) in regenerative medicine. We show that serious and adequate clinical research demonstrates that tissue regeneration with UA-ADRCs is safe and effective. ADRCs are neither 'fat stem cells' nor could they exclusively be isolated from adipose tissue, as ADRCs contain the same adult (depending on the definition) pluripotent or multipotent stem cells that are ubiquitously present in the walls of small blood vessels. Of note, the specific isolation procedure used has significant impact on the number and viability of the cells and hence on safety and efficacy of UA-ADRCs. Furthermore, there is no need to further separate adipose-derived stem cells (ASCs) from ADRCs if the latter were adequately isolated from adipose tissue. Most importantly, UA-ADRCs have the physiological capacity to adequately regenerate tissue without need for manipulating, stimulating and/or (genetically) reprogramming the cells for this purpose. Tissue regeneration with UA-ADRCs fulfills the criteria of homologous use.

Background: Recently, the management of musculoskeletal disorders with the patients' own stem cells, isolated from the walls of small blood vessels, which can be found in great numbers in the adipose tissue, has received considerable attention. On the other hand, there are still misconceptions about these adipose-derived regenerative cells (ADRCs) that contain vascular-associated pluripotent stem cells (vaPS cells) in regenerative medicine. Methods: Based on our previous publications on this topic, we have developed a concept to describe the significance of the ADRCs/vaPS cells in the field of orthobiologics as briefly as possible and at the same time as precisely as possible. Results: The ADRCs/vaPS cells belong to the group of orthobiologics that are based on autologous cells. Because the latter can both stimulate a patient’s body's localized self-healing power and provide new cells that can integrate into the host tissue during the healing response when the localized self-healing power is exhausted, this group of orthobiologics appears more advantageous than cell-free orthobiologics and orthobiologics that are based on allogeneic cells. Within the group of orthobiologics that are based on autologous cells, enzymatically isolated, uncultured ADRCs/vaPS cells have several advantages over non-enzymatically isolated cells/microfragmented fat as well as over uncultured bone marrow aspirate concentrate and cultured cells (adipose-derived stem cells, bone marrow-derived mesenchymal stem cells). Conclusions: The use of ADRCs/vaPS cells can be seamlessly integrated into modern orthopedic treatment concepts, which can be understood as the optimization of a process which - albeit less efficiently - also takes place physiologically. Accordingly, this new safe and effective type of treatment is attractive in terms of holistic thinking and personalized medicine.

Uncultured, unmodified, autologous, adipose-derived regenerative cells (UA-ADRCs) are a safe and effective treatment option for various musculoskeletal pathologies. However, it is unknown whether the composition of the final cell suspension systematically varies with the subject's individual age, sex, body mass index and ethnicity. UA-ADRCs were isolated from lipoaspirate from n=232 subjects undergoing elective lipoplasty using the Transpose RT system (InGeneron, Inc.; Houston, TX, USA). The UA-ADRCs were assessed for the number of nucleated cells, cell viability and the number of viable nucleated cells per gram of adipose tissue harvested. Cells from n=37 subjects were further characterized using four-channel flow cytometry. The present study shows, for the first time, that key characteristics of UA-ADRCs can be independent of the subject's age, sex, BMI and ethnicity. This result has important implications for the general applicability of UA-ADRCs in regeneration of musculoskeletal tissue. Future studies must determine whether in-dependence of key characteristics of UA-ADRCs of the subject's individual age, sex, BMI and eth-nicity only applies to the system used in the present study, or also to others of the more than 25 different experimental methods and commercially available systems used to isolate UA-ADRCs from lipoaspirate that have been described in the literature.

Background: This study tested the hypothesis that treatment of symptomatic, partial-thickness rotator cuff tear (sPTRCT) with fresh, uncultured, unmodified, autologous adipose derived regenerative cells (UA-ADRCs) isolated from lipoaspirate at the point of care is safe and more effective than corticosteroid injection. Methods: Subjects aged between 30 and 75 years with sPTRCT who did not respond to physical therapy treatments for at least six weeks were randomly assigned to receive a single injection of an average 11.4×10⁶ UA-ADRCs (in 5 mL liquid; mean cell viability: 88%) (n=11; modified intention-to-treat (mITT) population) or a single injection of 80 mg of methylprednisolone (40 mg/ml; 2 mL) plus 3 mL of 0.25% bupivacaine (n=5; mITT population), respectively. Safety and efficacy were assessed using the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), RAND Short Form-36 Health Survey and pain visual analogue scale (VAS) at baseline (BL) as well as three weeks (W3), W6, W9, W12, W24, W32, W40 and W52 post treatment. Fat-saturated T2 weighted magnetic resonance imaging of the shoulder was performed at BL as well as at W24 and W52 post treatment. Results: No severe adverse events related to the injection of UA-ADRCs were observed in the 12 months post treatment. The risks connected with treatment of sPTRCT with UA-ADRCs were not greater than those connected with treatment of sPTRCT with corticosteroid injection. However, one subject in the corticosteroid group developed a full rotator cuff tear during the course of this pilot study. Despite the small number of subjects in this pilot study, those in the UA-ADRCs group showed statistically significantly higher mean ASES total scores at W24 and W52 post treatment than those in the corticosteroid group (p < 0.05). Discussion: This pilot study suggests that the use of UA-ADRCs in subjects with sPTRCT is safe and leads to improved shoulder function without adverse effects. To verify the results of this initial safety and feasibility pilot study in a larger patient population, a randomized controlled trial on 246 patients suffering from sPTRCT is currently ongoing.