ARTICLE | doi:10.20944/preprints202308.2084.v1
Subject: Medicine And Pharmacology, Other Keywords: Anaerobic capacity; blood lactate; maximal lactate steady state; VLaMax
Online: 30 August 2023 (12:03:24 CEST)
Background: The purpose of this study was to ascertain the reliability of two 15-sec sprint cycling tests in men and women to estimate the maximum rate of glycolysis or lactate production (VLa-Max). Methods: Eighteen men and twelve women completed two sprint sessions over 1-week. A 10-min warm-up preceded a 3 µl blood lactate (BLC) sample, after which a 15-sec sprint was completed; cyclists then rested passively while multiple lactate samples were taken until levels peaked. VLaMax was calculated as (Peak BLC – Pre BLC) * (15-sec – Talac)-1. Trial differences and reliability across trials were analyzed using a paired-sample t-test, Pearson correlation, ICC, and Bland-Altman analysis with α=0.05 for all tests; data are reported as mean ± sd. Results: Power (W) was similar across trails (773.0 ±143.5 vs. 758.2 ± 127.4; p = 0.333) and coefficient of varia-tion (CV) of 4.7%. VLaMax was similar (0.673 ± 0.024 vs 0.635 ± 0.237; p = 0.280), but only moder-ately reliably across trials with a CV, ICC, and R value of 18.6%, 0.661, and 0.67, respectively. Conclusions: A 15-sec VLaMax cycling sprint is moderately reliable being affected both by the lac-tate measurement and other variables used in the calculation. More research may offer ways to improve reliability.
REVIEW | doi:10.20944/preprints202009.0299.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Lactate Shuttle; Lactate; Exercise; Postabsorptive Metabolism; Postprandial Metabolism; Gene Adaptation; Muscle; Fiber Type; Gluconeogenesis; Glycogenolysis
Online: 13 September 2020 (16:31:28 CEST)
After a Century it is time to turn the page on understanding of lactate metabolism and appreciate that lactate shuttling as an important component of intermediary metabolism in vivo. Cell-Cell and intracellular Lactate Shuttles fulfill purposes of energy substrate production and distribution as well as cell signaling under fully aerobic conditions. Recognition of lactate shuttling came first in studies of physical exercise where roles of driver and recipient cells and tissues were obvious. Moreover, the presence of lactate shuttling as part of postprandial glucose disposal has been recognized. Mitochondrial respiration creates the physiological sink for lactate disposal in vivo. Repeated lactate exposure from regular exercise results in adaptive processes such as mitochondrial biogenesis and other healthful circulatory and neurological characteristic such as improved physical work capacity, metabolic flexibility and cognition. The importance of lactate and lactate shuttling in healthful living is further emphasized when lactate signaling and shuttling are dysregulated as occur in illness and injury. Like a Phoenix, lactate rises again in importance in 21st Century Biology.
REVIEW | doi:10.20944/preprints202202.0353.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: Diabetic; Chronic Kidney Disease; Metformin; Acidosis Lactate
Online: 28 February 2022 (09:28:33 CET)
Background: Diabetes Mellitus is a metabolite disorder with parameters of high blood sugar levels. In the management of diabetes can be used the drug metformin is the gold of choice to achieve a therapeutic effect and rarely causes side effects of the drug, but it still has debate view. However, if used in excessive doses for patients with kidney disease, it will be contraindicated with side effects such as lactic acidosis. Objective: This study aims to evaluate the side effect of Metformin for diabetic kidney diseases (DKD) patients. Method: This study used the Narrative Review Method that was obtained from 2011 to 2021, in the English language from PubMed, Google Scholar, and Cochrane Library. Results: Metformin is at the forefront of the treatment of type 2 diabetes mellitus (DM2). Metformin is likely to have lactic acidosis-related adverse effects in chronic kidney disease (CKD) patients, such as increased arterial lactate. Lactic acidosis is defined as an increase in arterial lactate with an indicator of more than five mmol/L and an arterial blood pH of less than 7.35. Metformin-induced lactate levels are considered to be below the parameters. DKD risk factors can be conceptually classified as several susceptibility factors, initiation factors, and developmental factors. The two most prominent risk factors are hyperglycemia and hypertension. Conclusion: Metformin can increase lactate levels in CKD patients but is still below the parameters of lactic acidosis. This study may have some weaknesses and requires further prospective research to validate the results.
ARTICLE | doi:10.20944/preprints202008.0034.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: Acupuncture; lactate; heart rate; physical performance; sustainability
Online: 2 August 2020 (14:46:22 CEST)
Studies have demonstrated the positive effects of acupuncture on athletic performance. The aim of this study was to determine the acute effects of acupuncture on heart rate, the perceived exertion scale and lactate levels in recreational athletes. Fifteen competitive males engaged in HIIT. The characteristic was 29.86±2.51 years old, heart rate reserve 59.00±3.33, lactate 3.17±0.50 mM/DL. The subjects were submitted to two exercise sessions. Both training sessions consisted of 10 burpees, 12 thrusters and 14 box jumps (75 cm high) for 12 minutes. Activity intensity was between 85 and 95% of maximum heart rate. Acupuncture points: ST36, L3, LI11. The student’s t-test was adopted, Shapiro-Wilk test was applied for normality, and Pearson correlation. There was a positive correlation of r = 0.69 between lactate levels and heart rate. Lactate: Lac1 15.00±1.18 – Lac2 19.59± 1.46 p= 0.0001*; Heart 1rate: HRF 163.71±7.27 – HRF2 177.60±6.99 p=0.0001*; Blood pressure: SBP1 174.86±1.57 – SBP2 180.86±1.77 p= 0.0001*; PES1: 19.4±1.14; PES2 16.8±0.84 p= 0.0001*; weight1 – 182,57±12,05; weight 2 206,43±11,39 p=0.0325*. Acupuncture increased lactate accumulation, heart rate and blood pressure, suggesting that the exertion reached after acupuncture is higher than without acupuncture. The acupuncture technics improved the athlete performance.
ARTICLE | doi:10.20944/preprints202308.1141.v1
Subject: Medicine And Pharmacology, Hematology Keywords: sickle cell; cardiac markers; vaso-occlusive; troponin; lactate dehydrogenase
Online: 16 August 2023 (03:18:46 CEST)
Background: Millions of people worldwide suffer from a genetic hemoglobinopathy known as sickle cell disease (SCD). It is a long-term condition marked by progressive multiorgan failure. Among SCD patients, cardiovascular complications are the main leading cause of death. Cardiovascular complication raises cardiac markers level as well as sickle cell vaso-occlusive crisis (VOC). This makes it challenging to determine the source. Methods: This research aims to identify the association between cardiac markers and myocardial infarction in SCD patients At King Abdulaziz University (KAUH) in Jeddah, Saudi Arabia. This retrospective study was conducted from June 2022 to March 2023. All patients with SCD who were 18 years and above were enrolled. Cardiac markers' associations with age, emergency room visits, ECG, blood transfusion, hydroxyurea, anticoagulants, and mortality were analyzed. Result: 537 patient records were screened during the study period, of which 270 met the inclusion criteria. Among these, 144 (53.3%) were female. The prevalence of elevated LDH, troponin, and CK-MB among the SCD patients who visited ER for the VOC was 78.5%, 9.3%, and 6.3%, respectively. Overall, there was a significant relationship between the cardiac marker level and the number of ER visits, age and mortality (p= 0.01), but there was no significant association between the cardiac marker level and for each of the following: hydroxyurea use, antiplatelet/anticoagulant use, needing of blood transfusion and ECG abnormalities. This retrospective research shed light on the significance of cardiac marker levels in patients with SCD. The level of cardiac markers was remarkably linked with age, frequency of ER visits, and patients' states.
ARTICLE | doi:10.20944/preprints202311.0570.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Endurance; mountain running; lactate; stryd; performance; indirect calorimetry.; metabolism; overload
Online: 8 November 2023 (15:41:20 CET)
The need to carry different items, which become an extra load, is a characteristic of trail running. The aim of this study is to determine physiological-metabolic changes produced by running with extra load. Four male well-trained trail runners completed three treadmill maximal metabolic tests carrying different loads (0% (L0), 5% (L5), and 10% (L10) of their body mass) in a weighted vest. Gasses exchange was monitored to assess ventilatory thresholds 1 (VT1), and 2 (VT2), zone of maximal fat oxidation, and peak oxygen consumption (VO2peak). Heart rate (HR), power and velocity (V) were tracked for comparing their behavior. A repeated measures ANOVA showed significant differences in V (p<.001; ηp2= 0.910) as a limitation for reaching peak velocity (Vpeak) with L10 respect to L0 (p=0.001), and L5 (p=0.011). Power expression showed differences (p=0.068; ηp2= 0.592). It tended to be greater with L10 than L0 (p=0.057), despite achieving lower V. VT2 tended to occur at different %VO2peak (p=0.069; ηp2= 0.591). L5 VT2 was reached at higher %VO2peak than L0 (p=0.062), and L10 (p=0.071). ANOVA also showed a tendency to signification for V at this point (p= 0.098; ηp2= 0.538). In conclusion, L10 seems to limit Vpeak while L5 may delay VT2 expression.
ARTICLE | doi:10.20944/preprints202307.0010.v1
Subject: Medicine And Pharmacology, Emergency Medicine Keywords: Sepsis biomarkers; mortality; MR-proADM; SOFA score; Lactate; molecular diagnosis
Online: 3 July 2023 (08:10:55 CEST)
Early diagnosis and appropriate treatments are crucial to reducing mortality risk in septic patients. Low SOFA scores and current biomarkers may not discern adequately patients that could develop severe organ dysfunction or have an elevated mortality risk. The aim of this prospective observational study is to evaluate the predictive value of the biomarkers midregional proadrenomedullin (MR-proADM), procalcitonin (PCT), C-Reactive Protein (CRP), and lactate for 28-day mortality in patients with sepsis and a SOFA score ≤ 6. 284 patients were included, with a 28-day all-cause mortality of 8.45 % (N=24). Non-survivors were older (p=0.003), required mechanical ventilation (p=0.04) and were ventilated for longer (p=0.02), had a higher APACHE II (p=0.015) and SOFA (p=0.027) scores. Lactate showed the highest predictive ability for all-cause 28-day mortality with an area under the receiver-operating characteristic curve (AUROC) of 0.67 (0.55–0.79). The AUROC for all-cause 28-day mortality in patients with community-acquired infection was 0.69 (0.57–0.84) for SOFA, and 0.70 (0.58–0.82) for MR-proADM. A 2.1 nmol/L cut-off point for this biomarker in this subgroup of patients discerned with 100% sensibility survivors from non-survivors at 28 days. In patients with community acquired sepsis and initial SOFA score ≤ 6, MR-proADM could help identify patients at risk of 28-day mortality.
REVIEW | doi:10.20944/preprints202306.1065.v1
Subject: Medicine And Pharmacology, Surgery Keywords: oxidative stress; dressing; lactate; polylactide; reactive oxygen species; wound healing
Online: 14 June 2023 (15:32:50 CEST)
Although a slight imbalance between oxidative and antioxidative mediators is part of normal physiology that enables cell aging and the removal of dead cells, burns disturb this equilibrium locally and systemically. Topical burn dressings may attenuate local and systemic oxidative stress and positively influence the post-burn clinical course. This review integrated knowledge regarding the impact of burn dressings on oxidative stress. Using keywords and in-text searches, literature was identified from PubMed, Google Scholar, and Google articles, and studies on local or topical applications of wound dressings and associated oxidative stress were selected. As im-balances between oxidative mediators and antioxidative agents significantly contribute to organ dysfunction and healing disturbance, we investigated oxidative stress on organs, metabolic changes, clinical results, and oxidative parameters influenced by applied dressings. We found positive local and systemic effects of external burn dressings in laboratory and animal tests; however, such studies were rare in humans. Nevertheless, we identified successful cases of semi-occlusive, occlusive, and biologically active dressings that reduce oxidative stress in hu-man burns. In particular, we highlight promising clinical and laboratory results from lac-tate-releasing dressings. Our review provides an invaluable resource for future development and clinical applications of burn dressings.
ARTICLE | doi:10.20944/preprints202308.1686.v1
Subject: Medicine And Pharmacology, Psychiatry And Mental Health Keywords: Schizophrenia; Lactate; Physical exercise; Creatine Kinase (CK); C-Reactive Protein (CRP)
Online: 24 August 2023 (08:20:32 CEST)
Background: Schizophrenia is a mental disorder associated with inflammatory and oxidative stress markers such as lactate; in addition, the rate of physical inactivity in this population is very high, which leads to physical and metabolic alterations. Aims: This study measured the effect of assisted physical exercise over lactate levels in schizophrenia. Methods: Stable outpatients with schizophrenia and a group of Healthy controls received two different programs of Physical exercise (Aerobic and Functional) in a clinical trial. Results: Patients had higher lactate compared to healthy controls before and after intervention, and had higher rate of lactate increase after activity. The finding of increased lactate in schizophrenia detected before and after physical exercise deserve further attention in biomarker studies and in the development of physical rehabilitation in schizophrenia, suggesting different profile of oxidative metabolism after physical exercise. Basal increased lactate may reflect mitochondrial dysfunction or metabolic dysregulation, and the higher rate of increase may reflect a different metabolic and oxidative process. Conclusion: The finding is in line with recent studies as surrogate of mitochondrial dysfunction in schizophrenia and points to the need of additional studies on mitochondrial activity in schizophrenia, and to additional care in the design of physical interventions in schizophrenia.
REVIEW | doi:10.20944/preprints202208.0452.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: lactate; lactic acid; glycolysis; carcinogenesis; malignant tumor; evolutionary oncology; Warburg effect
Online: 26 August 2022 (07:13:46 CEST)
The role of lactic acid (lactate) in cell metabolism has been significantly revised in recent dec-ades. Initially, lactic acid was attributed to the role of a toxic end product of metabolism, which accumulation in the cell and extracellular space leads to acidosis, muscle pain and other adverse effects. However, it has now become obvious that lactate is not only a universal fuel molecule and the main substrate for gluconeogenesis, but also one of the most ancient metabolites with signaling function, which has a wide range of regulatory activity. The Warburg effect described 100 years ago (that means intensification of glycolysis associated with high lactate production), which is characteristic of many malignant tumors, confirms the key role of lactate not only in physiological conditions, but also in pathologies. The study of lactate’s role in the malignant transformation becomes more relevant in the light of the “atavistic theory of carcinogenesis,” which suggests that tumor cells return to a more primitive hereditary phenotype during micro-evolution. In this review, we attempted to summarize the accumulated knowledges about the functions of lactate in cell metabolism and its role in the process of carcinogenesis, and to con-sider the possible evolutionary significance of the Warburg effect.
ARTICLE | doi:10.20944/preprints202005.0065.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: memory formation; moonlighting protein; protein-protein interaction; astrocyte-neuron lactate shuttle
Online: 5 May 2020 (06:09:47 CEST)
Long-term potentiation (LTP) is a molecular basis of memory formation. Here, we demonstrate that LTP critically depends on muscle fructose 1,6-bisphosphatase 2 (Fbp2) – a glyconeogenic enzyme and moonlighting protein protecting mitochondria against stress. We show that LTP induction regulates Fbp2 association with neuronal mitochondria and Camk2, and that the Fbp2-Camk2 interaction correlates with Camk2 autophosphorylation. Silencing of Fbp2 expression or simultaneous inhibition and tetramerization of the enzyme with a synthetic effector mimicking the action of physiological inhibitors (NAD+ and AMP) abolishes Camk2 autoactivation and blocks formation of the early phase of LTP and expression of the late phase LTP markers. Astrocyte-derived lactate reduces NAD+/NADH ratio in neurons and thus, diminishes the pool of tetrameric and increases the fraction of dimeric Fbp2. We therefore hypothesize that this NAD+-level-dependent increase of the Fbp2 dimer/tetramer ratio might be a crucial mechanism in which astrocyte-neuron lactate shuttle stimulates LTP formation.
ARTICLE | doi:10.20944/preprints202309.1801.v1
Subject: Medicine And Pharmacology, Emergency Medicine Keywords: cardiopulmonary resuscitation, out-of-hospital cardiac arrest, lactate, return of spontaneous circulation
Online: 28 September 2023 (02:50:40 CEST)
Background and Objectives: Effective strategy to cardiopulmonary resuscitation should be based on tissue perfusion. Our primary aim was to determine the association between capillary lactate values and initial rhythm as well as probability of return of spontaneous circulation in out-of-hospital cardiac arrest patients. Materials and Methods: This prospective observational cohort study included all patients with non-traumatic out-of-hospital cardiac arrest, older than 18 years, resuscitated by a prehospital emergency medical team between April 2020 and June 2021. Capillary lactate samples were collected at the time of arrival and every 10 minutes after first measurement until the time of return of spontaneous circulation (ROSC) or if ROSC was not achieved at time of declaring death on scene. Results: 83 patients were enrolled in the study. ROSC was achieved in 28 patients (33,7%), 21 were admitted to the hospital (26,3%) and 6 (7,23%) of them were discharged from the hospital. At discharge all patients had Cerebral Performance Category Scale 1 or 2. Initial capillary lactate values were significantly higher in patients with non-shockable rhythm compared to the group with shockable rhythm (9,19 +/- 4,6 versus 6,43 +/- 3,81; p = 0.037). A significant difference persisted also in a second value taken 10 minutes after in-itial value (10,03 +/- 5,19 versus 5,18 +/- 3,47; p = 0.019). Capillary lactate values were higher in the ROSC group and non-ROSC group at the time of restored circulation (11,10 +/- 6,59 and 6,77 +/- 4,23, respectively; p = 0,047). Conclusions: Capillary lactate values are significantly lower in patients with a shockable first rhythm in OHCA. There is also a significant connection between a rise in capillary lactate level and ROSC.
ARTICLE | doi:10.20944/preprints202308.0088.v1
Subject: Social Sciences, Tourism, Leisure, Sport And Hospitality Keywords: menstrual cycle; running; kinetic variables; lactate concentration; heart rate; level of fatigue
Online: 2 August 2023 (02:28:34 CEST)
Background: Depending on the phase of the menstrual cycle the athlete is in, some kinetic, physiological and fatigue variables will show differences. The aim of this study is to analyze whether there are changes in these variables over the course of the menstrual cycle. Methods: Eight regular female runners and triathletes performed a maximal treadmill test, as well as a submaximal test (6’ stages at 50%, 60% and 80% of maximal aerobic speed) in each of the phases of the menstrual cycle: bleeding phase (day 2.4 ± 0.7), follicular phase (day 10.4 ± 2.2) and luteal phase (day 21.8 ± 2.1). Running dynamics were measured (using RunScribe) at the end of each test, as were lactate concentration, heart rate and fatigue (evaluated on a scale of 0 to 5). Results: Higher shock (G) values were recorded in the bleeding phase and higher vertical spring stiffness (kN/m) in the follicular phase. The phase of the menstrual cycle had a significant effect on average and peak heart rate, which was significantly higher in the follicular phase. Conclusions: Higher vertical spring stiffness was observed in the follicular phase, as well as higher peak and average heart rate.
REVIEW | doi:10.20944/preprints202109.0511.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: Wound; chronic wound; hypoxia; Lactate; Acidosis; Alkalosis; neoangiogenesis; ECM; Polylactide; polylactide membranes
Online: 30 September 2021 (12:18:52 CEST)
: Over time, we have come to recognize a very complex network of physiological changes enabling wound healing. An immunological process enables the body to distinguish damaged cells and begin a cleaning mechanism by separating damaged proteins and cells with matrix metallopro-teinases, a complement reaction, and free radicals. A wide variety of cell functions help to rebuild new tissue, dependent on energy provision and oxygen supply. Like in an optimized "biorector," disturbance can lead to prolonged healing. One of the earliest investigated local factors is the pH of wounds, studied in close relation to the local perfusion, oxygen tension, and lactate concentration. Granulation tissue with the wrong pH can hinder fibroblast and keratinocyte division and pro-liferation, as well as skin graft takes. Methods for influencing the pH have been tested, such as occlusion and acidification by the topical application of acidic media. In most trials, this has not changed the wound's pH to an acidic one, but it has reduced the strong alkalinity of deeper or chronic wound. Energy provision is essential for all repair processes. New insights into the metabolism of cells have changed the definition of lactate from a waste product to an indispensable energy provider in normoxic and hypoxic conditions. Neovascularization depends on oxygen provision and lactate, signaling hypoxic conditions even under normoxic conditions. An appropriate pH is necessary for successful skin grafting; hypoxia can change the pH of wounds. This review describes the close interconnections between the local lactate levels, metabolism, healing mechanisms, and pH. Furthermore, it analyzes and evaluates the different possible ways to support metabolism, such as lactate enhancement and pH adjustment. The aim of wound treatment must be the optimization of all these components. Therefore, the role of lactate and its influence on wound healing in acute and chronic wounds will be assessed.
ARTICLE | doi:10.20944/preprints202305.1059.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: corneal enendothelial dystrophy; Slc4a11; barrier function; lactate transporters; Src kinase; oxidative stress; Visomitin
Online: 15 May 2023 (15:50:03 CEST)
Purpose: Inducible Slc4a11 KO leads to corneal edema by disruption of the pump and barrier functions of the corneal endothelium (CE). The loss of Slc4a11 NH3-activated mitochondrial uncoupling leads to mitochondrial membrane potential hyperpolarization-induced oxidative stress. The goal of this study is to investigate the link between oxidative stress and failure of pump and barrier functions and test different approaches to revert the process. Methods: Mice homozygous for Slc4a11 Flox and Estrogen receptor –Cre Recombinase fusion protein alleles at 8 weeks of age were fed Tamoxifen (Tm) enriched chow (0.4 g/Kg) for 2 weeks, and controls were fed normal chow. During the initial 14 days, Slc4a11 expression, corneal thickness (CT), stromal [lactate], Na+-K+ ATPase activity, mitochondrial superoxide levels, expression of lactate transporters, and activity of key kinases were assessed. In addition, barrier function was assessed by fluorescein permeability, ZO-1 tight junction integrity, and cortical cytoskeleton F-actin morphology. Results: Tm induced a rapid decay in Slc4a11 expression that was 84% complete at 7 days and 96% at 14 days of treatment. Superoxide levels increased significantly by day 7; CT and fluorescein permeability by day 14. Tight junction ZO-1 distribution and cortical cytoskeleton were disrupted at day 14 concomitant with decreased expression of Cldn1 yet an increase in tyrosine phosphorylation. Stromal lactate increased by 60%, Na+-K+ATPase activity decreased by 40%, and expression of lactate transporters MCT2 and MCT4 significantly decreased, but MCT1 was unchanged at 14 days. Src kinase was activated but not Rock, PKCα, JNK, or P38Mapk. Mitochondrial antioxidant Visomitin (SkQ1, mitochondrial targeted antioxidant) or Src kinase inhibitor eCF506 significantly slowed the increase in CT, with concomitant decreased stromal lactate retention, improved barrier function, reduced Src activation and Cldn1 phosphorylation, and rescued MCT2 and MCT4 expression. Conclusions: Slc4a11 KO-induced CE oxidative stress triggered increased Src kinase activity that results in perturbation of pump components and barrier function of the CE.
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: hyperoxaluria; oxalate; inhibitor; small molecule drug; glycolate oxidase; lactate dehydrogenase; liver selective distribution
Online: 31 December 2020 (08:59:47 CET)
Primary hyperoxalurias (PHs) are a group of inherited alterations of the hepatic glyoxylate metabolism. PHs classification based on gene mutations parallel a variety of enzymatic defects, and all involve the harmful accumulation of calcium oxalate crystals that produce systemic damage. These geographically widespread rare diseases have a deep impact in the life quality of the patients. Until recently, treatments were limited to palliative measures and kidney/liver transplants in the most severe forms. Efforts made to develop pharmacological treatments succeeded with the biotechnological agent lumasiran, a siRNA product against glycolate oxidase, which has become the first effective therapy to treat PH1. However, small molecule drugs have classically been preferred since they benefit from experience and have better pharmacological properties. The development of small molecule inhibitors designed against key enzymes of glyoxylate metabolism is on the focus of research. Enzyme inhibitors are successful and widely used in several diseases and their pharmacokinetic advantages are well known. In PHs, effective enzymatic targets have been determined and characterized for drug design and interesting inhibitory activities have been achieved both in vitro and in vivo. This review describes the most recent advances towards the development of small molecule enzyme inhibitors in the treatment of PHs, introducing the multi-target approach as a more effective and safe therapeutic option.
ARTICLE | doi:10.20944/preprints202310.1420.v1
Subject: Public Health And Healthcare, Other Keywords: acute coronary syndrome; peripheral perfusion index; arterial blood gas; lactate; diagnostic metrics; noninvasive techniques
Online: 23 October 2023 (10:30:37 CEST)
This study aimed to investigate the potential correlations and differences between patients with Acute Coronary Syndrome (ACS) and controls. Emphasis was placed on examining the relationship between arterial blood gas PH value and arterial blood gas lactate value as well as assessing the utility of the Peripheral Perfusion Index (PI) in ACS management. Materials and Methods: A prospective observational study was conducted between January 1, 2023, and July 1, 2023, involving 60 ACS patients and 30 control subjects in an emergency department. The diagnosis of ACS was confirmed by experienced emergency physicians, and various parameters, such as peripheral perfusion index, blood gas values, and cardiac biomarker values, were collected. The statistical analyses included Pearson’s chi-square test, Mann-Whitney U test, Student’s t-test, and others, using SPSS version 18.0. There were significant differences in the mean age, perfusion index, and lactate levels between the patient and control groups. A robust negative correlation was found between age and PI, and a moderate negative correlation was observed between pH and lactate levels (r = -0.301, p=0.004). The perfusion index in the patient group was significantly lower, indicating its potential diagnostic utility. The findings demonstrate the importance of arterial blood gas pH and lactate values in understanding ACS patient profiles, emphasizing the potential of PI as a noninvasive diagnostic method. The negative correlation between pH and lactate levels may offer valuable insights into risk stratification and treatment strategies for patients with ACS.
ARTICLE | doi:10.20944/preprints201912.0311.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: adipose tissue; mesenchymal stem cells; regenerative medicine; lipocell; extracellular matrix preservation; ringer’s lactate; liposuction
Online: 24 December 2019 (07:53:44 CET)
This work aims to characterize a new method to recover low-manipulated human adipose tissue, enriched of adipose tissue-derived mesenchymal stem cells (ATD-MSCs) for autologous use in regenerative medicine applications. Lipoaspirated fat collected from patients was processed through Lipocell, a II-a medical device for dialysis of adipose tissue, by varying filter sizes and washing solutions. ATD-MSCs yield was measured with flow cytometry after SVF isolation in fresh and cultured samples. Purification from oil and blood was measured after centrifugation with spectrophotometer analysis. Extracellular matrix preservation was assessed through H&E staining and biochemical assay for total collagen, type-2 collagen, and GAGs quantification. Flow cytometry showed a 2-fold increase of ATD-MSCs yield in treated samples in comparison with untreated lipoaspirate; no differences where reported when varying filter size. The association of dialysis and washing thoroughly removed blood and oil from samples. Tissue architecture and extracellular matrix integrity were unaltered after Lipocell processing. Dialysis procedure associated with Ringer’s lactate preserves the proliferation ability of ATD-MSCs in cell culture. The characterization of the product shows that Lipocell is an efficient method to purify the tissue from undesired byproducts, preserving ATD-MSCs vitality and ECM integrity, resulting in a promising tool for regenerative medicine applications.
ARTICLE | doi:10.20944/preprints202202.0290.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: calcium lactate pentahydrate; monocalcium phosphate monohydrate; mechanical activation; powder; brushite; monetite; calcium pyrophosphate; ceramics; biocompatibility
Online: 23 February 2022 (12:07:43 CET)
Ceramic samples based on b-calcium pyrophosphate b-Ca2P2O7 were prepared using firing at 900, 1000, and 1100 oC from powders of g-calcium pyrophosphate g-Ca2P2O7 with preset molar ratios Ca/P=1; 0,975 and 0,95. To prepare powders of g-calcium pyrophosphate g-Ca2P2O7 with preset molar ratio Ca/P=1; 0,975 and 0,95 powder mixtures based on calcium lactate pentahydrate Ca(C3H5O3)2⋅5H2O and, monocalcium phosphate monohydrate Ca(H2PO4)2⋅H2O were treated in an aqua medium in mechanical activation conditions, dried, disaggregated in acetone, and heat-treated at 600 oC. The phase composition of powder mixtures after treatment if planetary mill in aqua medium included both brushite CaHPO4⋅2H2O or monetite CaHPO4, and starting salts. The phase composition of all powder mixtures after disaggregation in acetone in planetary mill included monetite CaHPO4 and starting salts. After heat treatment at 600 oC according to the XRD data phase composition of all powder mixtures was presented by g-calcium pyrophosphate g-Ca2P2O7. The grain size of ceramics increased both with the growth of firing temperature and with decreasing of molar ratio Ca/P of powder mixtures. Calcium polyphosphate (t melt =960–968 oC) formed from monocalcium phosphate monohydrate Ca(H2PO4)2⋅H2O acted like a liquid phase sintering additive. It was confirmed by tests in vitro, that prepared ceramic materials with preset molar ratio Ca/P=1; 0,975 and 0,95 and phase composition presented by b-calcium pyrophosphate b-Ca2P2O7 according to XRD data were biocompatible and could maintain bone cells proliferation.
ARTICLE | doi:10.3390/sci2020043
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: lactate dehydrogenase; alanine transaminase; MDR2 knockout; dissolution dynamic nuclear polarization; perfused precision cut liver slices
Online: 10 June 2020 (00:00:00 CEST)
The clinical characterization of small hepatocellular carcinoma (HCC) lesions in the liver and differentiation from heterogeneous inflammatory or fibrotic background is important for early detection and treatment. Metabolic monitoring of hyperpolarized 13C-labeled substrates has been suggested as a new avenue for diagnostic magnetic resonance. The metabolism of hyperpolarized [1-13C]pyruvate was monitored in mouse precision-cut liver slices (PCLS) of aged MDR2-KO mice, which served as a model for heterogeneous liver and HCC that develops similarly to the human disease. The relative in-cell activities of lactate dehydrogenase (LDH) to alanine transaminase (ALT) were found to be 0.40 ± 0.06 (n = 3) in healthy livers (from healthy mice), 0.90 ± 0.27 (n = 3) in heterogeneously inflamed liver, and 1.84 ± 0.46 (n = 3) in HCC. Thus, the in-cell LDH/ALT activities ratio was found to correlate with the progression of the disease. The results suggest that the LDH/ALT activities ratio may be useful in the assessment of liver disease. Because the technology used here is translational to both small liver samples that may be obtained from image-guided biopsy (i.e., ex vivo investigation) and to the intact liver (i.e., in a non-invasive MRI scan), these results may provide a path for differentiating heterogeneous liver from HCC in human subjects.
ARTICLE | doi:10.20944/preprints202304.0704.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Hypertensive emergency; diagnosis; lactate dehydrogenase; high sensitivity cardiac troponin T; brain natriuretic peptide; area under the curve
Online: 21 April 2023 (09:35:58 CEST)
Keywords: Hypertensive emergency; diagnosis; lactate dehydrogenase; high sensitivity cardiac troponin T; brain natriuretic peptide; area under the curve.
ARTICLE | doi:10.20944/preprints202104.0195.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: doubly labeled water; total energy expenditure; physical activity level; lactate threshold, physical fitness; International Physical Activity Questionnaire
Online: 7 April 2021 (11:32:02 CEST)
Adequate energy intake is critical for the healthy longevity of older adults, and the estimated energy requirement is determined by total energy expenditure (TEE). We aimed to identify the relationship between measured aerobic capacity and TEE, activity energy expenditure (AEE) or physical activity level (PAL) with the doubly labeled water (DLW) methods in the advanced older adults. A total of 12 physically independent older adults (10 males and 2 females) aged between 81 to 94 years participated in this study. Aerobic capacity was evaluated according to the lactate threshold (LT). TEE under free-living conditions was assessed using the DLW method, and self-reported physical activity was obtained through the Japanese version of the International Physical Activity Questionnaire (IPAQ). LT was significantly positively correlated with TEE, AEE, and PAL after adjustment for age and sex (ρ= 0.77 (P<0.01), 0.86 (p<0.01), and 0.86 (p<0.01), respectively). We found the LT as an aerobic capacity is positively and independently correlated with TEE, AEE or PAL. The present results suggest that maintaining aerobic capacity is an important factor for preventing frailty, although further research is needed to multisite studies and many samples.
ARTICLE | doi:10.20944/preprints202209.0488.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: carrot juice; human gut microbiota; fermentation; prebiotic; lactate; Lactobacillus fermentum; Lactobacillus salivarius; Lactobacillus mucosae; Bacteroides uniformis; Enterococcus faecium
Online: 30 September 2022 (11:19:07 CEST)
Carrot juice and its associated beverage products are well-known healthy drinks all over the world. However, what effect carrot juice has on the human gut microbiota and how it is fermented by the intestinal microbes have not been studied. Here, using an in vitro model of anaerobic fermentation, we demonstrated that carrot juice could be fermented into lactate and acetate by the human gut microbiota. 16S high-throughput sequencing and bioinformatic analyses indicated that fermentation of carrot juice could significantly change the composition of the human gut microbiome. Interestingly, carrot juice remarkably increased the abundances of beneficial bacteria, including Lactobacillus fermentum, Lactobacillus salivarius, Lactobacillus mucosae and Bacteroides uniformis and decreased the population of opportunistic pathogenic bacteria, such as Enterococcus faecium in the gut. Collectively, our study illustrates a favorable effect of carrot juice on the human gut microbiota and lays a foundation for the development of carrot juice as a novel prebiotic agent.
REVIEW | doi:10.20944/preprints202203.0170.v2
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: cancer; DNA informational entropy; cell compartmentation; evolutionary Biology; lactate dehydrogenase (LDH); lactic acid; metabolism; thermodynamic entropy; Warburg effect
Online: 17 March 2022 (03:37:53 CET)
Attempts to find and quantify the supposed low entropy of organisms and its preservation are revised. Absolute entropy of the mixed components of non-living biomass (around -1.6 x 103 J K-1 L-1) is the reference to which other entropy decreases would be ascribed to life. Compartmentation of metabolites and departure from the equilibrium of metabolic reactions account for 1 and 40-50 J K-1 L-1, respectively, decreases of entropy and, though small, are distinctive features of living tissues. DNA and proteins do not supply significant decreases of thermodynamic entropy, but their low informational entropy is relevant for life and its evolution. No other living feature contributes significantly to the low entropy associated to life. The photosynthetic conversion of radiant energy to biomass energy accounts for the most of entropy (2.8 x 105 J K-1 carbon kg-1) produced by living beings. The comparative very low entropy produced in other processes (around 4.8 x102 J K-1 L-1 day-1 in human body) must be rapidly exported outside as heat to preserve the low entropy decreases due to compartmentation and non-equilibrium metabolism. Enzymes and genes are described whose control minimize the rate of production of entropy and could explain selective pressures in biological evolution and the rapid proliferation of cancer cells.
REVIEW | doi:10.20944/preprints202102.0277.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: energy metabolism; oligodendrocyte; oligodendrocyte progenitor cell; myelin; remyelination; multiple sclerosis; glucose; ketone bodies; lactate; N-acetyl aspartate; demyelination
Online: 11 February 2021 (10:57:28 CET)
Central nervous system (CNS) myelin has a crucial role in accelerating the propagation of action potentials and providing trophic support to the axons. Defective myelination and lack of myelin regeneration following demyelination can both lead to axonal pathology and neurodegeneration. Energy deficit has been evoked as an important contributor to various CNS disorders, including multiple sclerosis (MS). This suggests that dysregulation of energy homeostasis in oligodendroglia may be an important contributor to myelin dysfunction and lack of repair observed in the disease. This article will focus on energy metabolism pathways in oligodendroglial cells and highlight differences dependent on the maturation stage of the cell. In addition, it will emphasize that the use of alternative energy sources by oligodendroglia may be required to save glucose for functions that cannot be fulfilled by other metabolites, thus ensuring sufficient energy input for both myelin synthesis and trophic support to the axons. Finally, it will point out that neuropathological findings in a subtype of MS lesions likely reflect defective oligodendroglial energy homeostasis in the disease.
REVIEW | doi:10.20944/preprints202309.0210.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: Brain-derived neurotrophic factor (BDNF); Alzheimer’s disease; exercise; osteocalcin; FNDC5/irisin; lactate; APP processing; dementia; cognition; learning and memory
Online: 5 September 2023 (03:45:49 CEST)
Brain-derived neurotrophic factor (BDNF) is a key molecule in promoting neurogenesis, dendritic and synaptic health, and neuronal survival, plasticity, and excitability, all of which are disrupted in neurological and cognitive disorders such as Alzheimer’s disease (AD). Extracellular aggregates of amyloid-β (Aβ) in the form of plaques and intracellular aggregates of hyperphosphorylated tau protein have been identified as major pathological insults in AD brain, along with immune dysfunction, oxidative stress, and other toxic stressors. Although aggregated Aβ and tau lead to decreased brain BDNF expression, early losses in BDNF prior to plaque and tangle formation may be due to other insults such as oxidative stress and contribute to early synaptic dysfunction. Physical exercise, on the other hand, protects synaptic and neuronal structure and function, with increased BDNF as a major mediator of exercise-induced enhancements in cognitive function. Here, we review recent literature on mechanisms behind exercise induced BDNF upregulation and its effects on improving learning and memory and on Alzheimer’s disease pathology. Mechanisms include elevations in peripheral BDNF-inducing hormones such as osteocalcin, FNDC5/irisin, and lactate. The fundamental mechanisms of how exercise impacts BDNF and cognition are unclear but are a prerequisite to developing new biomarkers and therapies to delay or prevent cognitive decline.
ARTICLE | doi:10.20944/preprints202107.0503.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Cytotoxicity; Glioblastoma multiform; Lactate dehydrogenase (LDH); Poly D- L-lactic-co-glycolic acid (PLGA); U-87 MG glioma cell lines
Online: 21 July 2021 (16:37:21 CEST)
PHLNs (polymeric lipid hybrid nanoparticles) are core–shell nanoparticle structures made up of polymer cores and lipid shells that have properties similar to both polymeric nanoparticles and liposomes. Methotrexate (MTX) loaded PLHNPs containing tween 80, phosphatidylcholine, poly D, L-lactic-co-glycolic acid (PLGA) & glyceryl tripalmitate prepared using solvent injection & homogenization method for glioblastoma treatment option. The MTX loaded PLHNPs optimized by Box–Behnken design to minimize particle size, higher entrapment efficacy, and maximize MTX concentration in the brain at 4h. The particle size, entrapment efficacy, concentration of drug in brain at 4h, zeta potential and AUC(Brain)/AUC(Plasma) ratio were in the range of 173.51-233.37nm, 70.56-86.34%, 6.38-12.38 μg/mL, 25.78-36.31mV & 1.02-5.32. in-vitro drug release studies, cellular internalization of optimized formulation against U-87 MG shows good anticancer effects.
ARTICLE | doi:10.20944/preprints202309.0449.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Type A acute aortic dissection; arterial lactate; aortic root replacement; aortic arch repair; valve-sparing aorta replacement; ascending aorta replacement; total arch replacement procedure
Online: 7 September 2023 (03:32:28 CEST)
Abstract: Type A acute aortic dissection is a serious condition within the acute aortic syndromes that demands immediate treatment. Despite advancements in diagnostic and referral pathways, the survival rate post-surgery currently sits at almost 20%. Our objective was to pinpoint clinical indicators for mortality and morbidity, particularly raised arterial lactate as a key factor for negative outcomes. Methods: All patients referred to the three cardiovascular centres between January 2005 and December 2022 were included in the study. The inclusion criteria required the presence of a lesion involving the ascending aorta, symptoms within 7 days of surgery, and referral for primary surgical repair of TAAAD based on recommendations, with consideration for other concomitant major cardiac surgical procedures needed during TAAAD and retrograde extension of TAAAD. We conducted an analysis of both continuous and categorical variables and utilized predictive mean matching to fill in missing numeric features. For missing binary variables, we used logistic regression to impute values. We specifically targeted early postoperative mortality and employed LASSO regression to minimize potential collinearity of over-fitting variables and variables measured from the same patient. Results: 633 patients were recruited for the study, out of which 449 patients had complete preoperative arterial lactate data. The average age of the patients was 64 years, and 304 patients were male (67.6%). The crude early postoperative mortality rate was 24.5% (110 out of 449 patients). The mortality rate did not show any significant difference when comparing conservative and extensive surgeries. However, malperfusion had a significant impact on mortality [48/131 (36.6%) vs 62/318 (19.5%), p<0.001]. Preoperative arterial lactates were significantly elevated in patients with malperfusion. The optimal prognostic threshold of arterial lactate for predicting early postoperative mortality in our cohort was ≥ 2.6 mmol/L. Conclusion: The arterial lactate concentration in patients referred for TAAAD is an independent factor for both operative mortality and postoperative complications. In addition to mortality, patients with an upper arterial lactate cut-off of ≥2.6 mmol/L face significant risks of VA ECMO and the need for dialysis within the first 48 hours after surgery. To improve recognition and facilitate rapid transfer and surgical treatment protocol, more diligent efforts are required in the management of malperfusion in TAAAD.
CASE REPORT | doi:10.20944/preprints201801.0227.v1
Subject: Medicine And Pharmacology, Urology And Nephrology Keywords: Lactate dehydrogenase (LDH), Computed Tomography (CT), Glomerular filtration rate (GFR), C reactive protein (CRP), Angiotensin converting enzyme inhibitor (ACEI) Angiotensin receptor blocker (ARB), Kidney Urinary bladder ( KUB), Dimercapto Succinic Acid (DMSA)
Online: 24 January 2018 (11:41:15 CET)
Renal artery thrombosis is a sporadic serious clinical condition which potentially cause renal infarction. Diagnosis of renal infarction can be delayed or missed due to non specific clinical presentation and overlapping appearance of medical and surgical phenomena. Early diagnosis supported by biochemical and radiological findings while appropriate management potentially improve morbidity and mortality. Persistent abdominal or flank pain with raised LDH and proteinuria on background of thromboembolism risk factors supports the diagnosis. Despite the rarity of the disease rapid identification with prompt medical or endovascular intervention could prevent irreversible renal parenchymal damage.