Increase In Lactate Concentration Research Articles

Acute Responses to Different Velocity-Loss Thresholds During Squat Training With and Without Blood-Flow Restriction.

To compare the acute effects on mechanical, metabolic, neuromuscular, and muscle contractile responses to different velocity-loss (VL) thresholds (20% and 40%) under distinct blood-flow conditions (free [FF] vs restricted [BFR]) in full squat (SQ). Twenty strength-trained men performed 4 SQ protocols with 60% 1-repetition maximum that differed in the VL within the set and in the blood-flow condition (FF20: FF with 20% VL; FF40: FF with 40% VL; BFR20: BFR with 20% VL; and BFR40: BFR with 40% VL). The level of BFR was 50% of the arterial occlusion pressure. Before and after the SQ protocols, the following tests were performed: (1)tensiomyography, (2)blood lactate, (3)countermovement jump, (4)maximal voluntary isometric SQ contraction, and (5)performance with the load that elicited a 1m·s-1 at baseline measurements in SQ. No "BFR × VL" interactions were observed. BFR protocols resulted in fewer repetitions and lower increases in lactate concentration than FF protocols. The 40% VL protocols completed more repetitions but resulted in lower mechanical performance and electromyography median frequency during the exercise than the 20% VL protocols. At postexercise, the 40% VL protocols also experienced greater blood lactate concentrations, higher alterations in tensiomyography-derived variables, and accentuated impairments in SQ and countermovement-jump performances. The 20% VL protocols showed an increased electromyography median frequency at postexercise maximal voluntary isometric contraction. Despite BFR-accelerated fatigue development during exercise, a given VL magnitude induced similar impairments in the distinct performance indicators assessed, regardless of the blood-flow condition.

Clinical characteristics of hemodynamics and laboratory parameters of recipients during orthotopic heart transplantation

Objective. To study the clinical and laboratory characteristics of recipients during orthotopic heart transplantation according to intraoperative monitoring. Materials and methods. The clinical and laboratory data of 38 patients who underwent orthotopic heart transplantation for vital indications in the period from 2022 to 2024 were studied. The average age of patients was (38.5 ± 13.5) years. There were 35 men (92.1%) and 3 women (7.9%). Peripheral oxygen saturation, arterial and central venous pressure were measured in each recipient delivered to the operating room at 5 stages of the operation during orthotopic heart transplantation. Results. The main cause of chronic heart failure with subsequent heart transplantation in all 38 (100%) patients was dilated cardiomyopathy. Statistically significant (p < 0.05) acidosis and hypercapnia in recipients during heart transplantation were most pronounced at the first stage of surgery, before the connection of a heart–lung machine. Acidosis during heart transplantation had a mixed metabolic and respiratory genesis with hypercapnia and lactatacidosis. A statistically significant (p < 0.05) increased lactate content at the first and second stages and statistically significant (p < 0.05) hyperglycemia at all stages of surgery were found. Central venous pressure was statistically significantly (p<0.05) higher than the reference values at the stages of sternum cutting and before the connection of the heart–lung machine. A direct statistically significant (p<0.05) correlation between the level of arterial blood pH and the level of central venous pressure (r=0.334) was established, with the corresponding linear regression equation: pH=4.7043+central venous pressure × 0.02391. Conclusions. Clinical and laboratory characteristics of recipients undergoing orthotopic heart transplantation demonstrated a direct correlation between mixed metabolic and respiratory acidosis and central venous pressure. Peripheral hemodynamic parameters in orthotopic heart transplantation were characterized by instability at the stage of heart–lung machine disconnection.

Circulating secretoneurin concentrations predict 90-day mortality in patients with cardiogenic shock

Abstract Background Secretoneurin (SN) concentrations have been found to provide strong prognostic information in critically ill patients. Accordingly, in this study we hypothesized that SN would provide prognostic information in patients with cardiogenic shock. Objectives To evaluate the utility of SN concentrations to predict 90-day mortality in two multicenter, prospective clinical trials including patients with cardiogenic shock. Methods We measured SN concentrations with a CE-marked ELISA in patients with cardiogenic shock of all etiologies (Cohort #1, n=168) and in patients with post-myocardial infarction cardiogenic shock (Cohort #2, n=45). Inclusion criteria in both cohorts focused on systolic blood pressure <90 mmHg and evidence of tissue hypoperfusion, including increased lactate concentrations. We used Cohort #1 for primary analysis and Cohort #2 for validation. We assessed association between SN concentrations and mortality by Kaplan-Meier curves and by univariate and multivariable Cox proportional hazard regression analysis. Results Median age was 67 and 69 years (Cohort #1 and #2) and the patients were predominantly male (74% and 67%, respectively). Median SN concentration on study inclusion was 53 pmol/L in Cohort #1 and 50 pmol/L in Cohort #2, and SN concentrations decreased from study inclusion to 72 hours (p=0.03 for trend). 90-day mortality was 42% in Cohort #1 and patients with high SN concentrations had worse outcome (Figure A). Adjusting for variables that were associated with 90-day mortality in univariate analysis and not part of the inclusion selection, i.e., age, sex, comorbidities, blood pressure, estimated glomerular filtration rate, treatment, and N-terminal pro-B-type natriuretic peptide concentrations, SN concentrations on study inclusion were still associated with 90-day mortality: hazard ratio per 100 pmol/L increment 1.97 (1.29-3.01), p=0.002. 90-day mortality was 45% in Cohort #2 and SN concentrations were predictive of 90-day mortality also in Cohort #2 (Figure B). Conclusion SN concentrations provide incremental prognostic information to established risk indices in the early phase of cardiogenic shock.A. Cohort #1 with SN tertilesB. Cohort #2 divided by SN median

Methods to characterize lactate turnover in aging and Alzheimer's disease; The LEAN study

BackgroundThere is evidence that chronic exercise can benefit the brain, but the effects vary markedly between studies. One potential mechanism for exercise-related benefit is the increase in systemic lactate concentration that is well-characterized to occur during exercise. Lactate is known to cross the blood brain barrier and can be used readily as a fuel for neurons. This may be particularly important in Alzheimer's Disease, which is characterized by cerebral hypometabolism. However, little is known about how whole-body lactate metabolism differs between older adults and individuals with cognitive impairment. This information is critical when considering potential differences in responses to exercise in various cognitive diagnosis groups. MethodsHere we describe the use of a “lactate clamp” procedure to adjust blood lactate levels to approximate those achieved during exercise, but while at rest. This trial will compare lactate oxidation between cognitively healthy older adults and cognitively impaired participants. We will further evaluate the effect of acute lactate infusion on cognitive performance. DiscussionThe findings of the study described here, the Lactate for Energy and Neurocognition trial (clinicaltrials.gov # NCT05207397) will add to our understanding of systemic lactate mechanics in cognitively healthy older adults and individuals with Alzheimer's Disease. These findings will be applicable to ongoing exercise trials and to future studies aimed at modulating systemic bioenergetic function in aging and Alzheimer's Disease.

Determining lactate concentrations in Korean indigenous calves and evaluating its role as a predictor for acidemia in calf diarrhea

BackgroundCalf diarrhea leads to high mortality rates and decreases in growth and productivity, causing negative effects on the livestock industry. Lactate is closely associated with metabolic acidosis in diarrheic calves. However, there have been no reports on lactate concentrations in Korean indigenous (Hanwoo) calves, especially those with diarrhea. This study aimed to determine the reference range of L-lactate and D-lactate concentrations in Hanwoo calves and to better understand the utility of lactate as predictive factors for acidemia in diarrheic calves.ResultsL-lactate and D-lactate concentrations were measured in healthy (n = 44) and diarrheic (n = 93) calves, and blood gas analysis was performed on diarrheic calves. The reference range in healthy calves was 0.2–2.25 mmol/L for L-lactate and 0.42–1.38 mmol/L for D-lactate. Diarrheic calves had higher concentrations of L-lactate and D-lactate than healthy calves. In diarrheic calves, L-lactate and D-lactate each had weak negative correlation with pH (r = − 0.31 and r = − 0.35). In diarrheic calves with hyper-L-lactatemia, the combined concentrations of L-lactate and D-lactate had moderate correlation with pH (r = − 0.51) and anion gap (r = 0.55). Receiver operating characteristic analysis showed D-lactate had fair predictive performance (AUC = 0.74) for severe acidemia, with an optimal cut-off value of > 1.43 mmol/L. The combined concentrations of L-lactate and D-lactate showed fair predictive performance for predicting acidemia (AUC = 0.74) and severe acidemia (AUC = 0.72), with cut-off values of > 6.05 mmol/L and > 5.95 mmol/L.ConclusionsThe determined reference ranges for L-lactate and D-lactate in Hanwoo calves enable the identification of hyper-L-lactatemia and hyper-D-lactatemia. Diarrheic calves exhibited increased lactate concentrations correlated with acid-base parameters. While the concentrations of L-lactate and D-lactate have limitations as single diagnostic biomarkers for predicting acidemia or severe acidemia, their measurement remains important, and L-lactate has the advantage of being measurable at the point-of-care. Assessing lactate concentrations should be considered by clinicians, especially when used alongside other clinical indicators and diagnostic tests. This approach can improve calf diarrhea management, contributing positively to animal welfare and providing economic benefits to farms.

Lactate as an early prognostic indicator in yellow phosphorus rodenticide-induced acute hepatic failure: a retrospective observational study in a tertiary care hospital

Introduction Acute hepatic failure due to yellow phosphorus rodenticide ingestion is often lethal. This study aimed to analyze demographic characteristics and prognostic indicators, focusing on hyperlactataemia as a potential early indicator of mortality in patients poisoned with yellow phosphorus rodenticide. Materials and methods This was a retrospective study of 96 patients poisoned with a yellow phosphorus-containing rodenticide (Ratol paste, which contains 3% yellow phosphorus). We examined demographic details, clinical symptoms, and biochemical markers to identify prognostic indicators. Results Demographics were similar among survivors and non-survivors. Mortality (36.5%) correlated with a higher ingested dose and treatment delays, with a mean (±SD) of 5.26 ± 2.2 survival days among those who died. Symptoms, including gastrointestinal and neurological features, typically appeared 48 h after ingestion. Non-survivors developed increased aminotransferase activities (74.3%), prolonged prothrombin time (65.7%), and hyperbilirubinaemia (65.7%) during hospitalization, significantly more commonly compared to survivors (P < 0.0001). Hyperlactataemia (lactate concentration >2 mmol/L) was present in 97.1% of non-survivors, with increased serial lactate concentrations observed in 88.6%. The median (interquartile range) admission lactate concentration among non-survivors was 4.6 mmol/L (3.36–7.53 mmol/L), and their peak median (interquartile range) lactate concentration was 6.1 mmol/L (8.74–10.6 mmol/L). In non-survivors, an increased lactate concentration preceded increased aminotransferase activities and prolonged prothrombin time. Logistic regression and receiver operating characteristic curve analysis confirmed that a 24 h lactate concentration ≥2.67 mmol/L predicted death with 94.3% sensitivity and 91.8% specificity. Discussion The majority of patients who ingest yellow phosphorus remain asymptomatic initially and typically present to hospital following the onset of gastrointestinal symptoms, usually a day later. As progression to death occurs within a week of yellow phosphorus ingestion in most cases, determining prognosis as early as possible enables swift referral to a liver transplant centre. Based on our study, a 24 h lactate concentration ≥2.67 mmol/L appears to be an early prognostic indicator of death. In another study, a lactate concentration >5.8 mmol/L was found to be a poor prognostic indicator. Conclusions Hyperlactataemia on admission and increased serial lactate concentrations appear to be early poor prognostic signs in patients with yellow phosphorus-induced liver failure.

Overexpression of ubiquitin-conjugating enzyme 2T induces radiotherapy resistance in hepatocellular carcinoma by enriching regulatory T cells in the tumor microenvironment

To investigate the effect of overexpression of ubiquitin-conjugating enzyme 2T (UBE2T) on radiosensitivity of hepatocellular carcinoma (HCC). Hepa1-6 cells were transfected with a UBE2T-overexpressing or a control lentiviral vector, and the changes in their radiotherapy sensitivity and concentrations of glucose and lactate in the supernatant were assessed using colony-forming assay and colorimetric assay. The transfected cells were inoculated subcutaneously in nude mice or C57BL/6 mice, and tumor growth following irradiation were recorded. The xenografts were collected for analyzing infiltration of CD4+ T cells and regulatory T cells (Tregs) using flow cytometry and detecting expressions of HK1 and LDHA using Western blotting. The correlations of UBE2T expression with immune cell infiltration, glycolysis and Tregs in HCC were analyzed using CIBERSORT algorithm and TCGA database, and the results were verified in a co-culture system of Hepa1-6 cells and Tregs. UBE2T overexpression caused radiotherapy resistance in both cultured Hepa1-6 cells and xenografts in the tumor-bearing mouse models (especially in C57BL/6 mice). CIBERSORT analysis suggested that a high expression of UBE2T was associated with increased percentages of dendritic cells, T follicular helper cells, M2 macrophages, monocytes, lymphocytes and Tregs in HCC. The UBE2T-overexpressing xenografts showed an increased percentage of Tregs and enhanced expressions of HK1 and LDHA, and irradiation increased infiltration of CD4+ T cells and Tregs in the tumor microenvironment. Hepa1-6 cells overexpressing UBE2T showed a decreased glucose concentration and an increased lactate concentration. GSEA analysis suggested that a high UBE2T expression was positively correlated with increased glycolysis and Tregs infiltration in HCC. In the cell co-culture system, UBE2T overexpression significantly enhanced lactate production, proliferation and immunosuppressive functions of Tregs. A high UBE2T expression results in radiotherapy resistance of HCC possibly by enhancing glycolysis and cause enrichment of Tregs in the tumor microenvironment.

#1316 Sirtuin 3 promotes renal gluconeogenesis in fibrotic kidneys

Abstract Background and Aims Decreased renal gluconeogenesis is currently identified as a hallmark of chronic kidney disease (CKD), which may contribute to renal fibrosis. Sirt3 is a crucial metabolic sensor that regulates ATP generation, mitochondrial adaptive response to stress, and glucose metabolism. It has been shown that Sirt3 is renal protective in fibrotic kidneys, however its underlying mechanisms is not completely known. In this study, we aimed to investigated whether Sirt3 inhibits CKD associated renal fibrosis through restoring renal gluconeogenesis. Method 1. Animal model of renal fibrosis (in vivo) For unilateral ureter obstructed (UUO) mouse model, a. Twenty-eight C57 mice were divided into four groups: sham + Vehicle, UUO + Vehicle, UUO + 3-TYP and UUO + HKL group. Mice were treated with saline or 20 mg/kg 3-TYP, an inhibitor of SIRT3 or 1 mg/kg HKL, an activator of SIRT3 daily (i.p.). b. Fourteen C57 mice were divided into two groups: Ad-Sirt 3 or Ad-LacZ (0.5 × 109 pfu/100 μL) was injected into the left renal artery before the UUO operation. Systemic glucose metabolism was evaluated by insulin and glucose tolerance tests. 7 or 14 days after operation, kidney tissues were collected and performed histopathological and molecular examination. 2. Primary murine renal tubules fibrosis (ex vivo) Primary renal tubules were isolated from C57 mouse of 4 weeks of age. 5 ng/mL TGF-β was added to culture medium for inducing fibrosis. After this Sirt3 was inhibited by 3-TYP (25 μm) or activated by HKL (2 μm) or overexpressed by adenovirus for different time periods (1, 3, 24, 48 hours). Protein or RNA samples were taken to evaluate renal fibrosis and gluconeogenesis. 3. Human renal epithelial (HK2) cells culture and treatment (in vitro) TGF-β stimulated HK2 cells were used as an in vitro model. Sirt3 was inhibited by 3-TYP or activated by HKL or overexpressed by adenovirus. Protein and RNA samples were taken to evaluate renal fibrosis and gluconeogenesis. Glucose and lactate were measured in supernatant of culture medium. Results In vivo, Masson staining showed that 3-TYP treatment increased the tubulointerstitial collagen deposition of UUO kidneys (Fig. 1A). WB results indicated that 3-TYP enhanced the increased expression of fibrotic marks (Fibronectin, Collagen-I, Vimentin) (Fig. 1B), and further reduced the expression of gluconeogenesis limitation enzyme (PCK1, FBP1) and transcription factors (PGC-1α and FOXO1) 14 days after UUO operation (Fig. 1C). Conversely, HKL treatment or overexpression of Sirt3 in UUO kidney reduced expression of fibrotic marks, increased the expression of gluconeogenesis markers (Fig. 1D-E). 3-TYP increased the lactate concentration in UUO kidneys (Fig. 1F). Insulin sensitivity and glucose clearance tests showed that treatment with 3-TYP further damaged the glucose homeostasis in UUO mice (Fig. 1G-J). Ex vivo, q-PCR results showed that the mRNA of Sirt3 was significantly decreased by time after TGF-β stimulation while the mRNA of FN, Snail was up-regulated and PCK1 and FBP1 were down-regulated (Fig. 2A-D). WB showed that 3-TYP treatment inhibited the expression of PCK1, FBP1 and PGC-1α, FOXO1 (Fig. 2E), however, HKL treatment or overexpressed of Sirt3 by adenovirus increased the expression of gluconeogenesis markers respectively in primary renal tubules (Fig. 2F). In vitro, WB showed that transfection of Sirt3 increased the expression of gluconeogenesis markers and decreased the expression of fibrotic marks of HK2 cells in a fibrotic condition (Fig. 3A-B). Moreover, 3-TYP treatment further decreased the mRNA expression of PCK1 and FBP1 in TGF-β stimulated HK2 cells (Fig. 3C-D). The increased lactate concentration and decreased glucose concentration in the culture medium of TGF-β stimulated HK2 cells were further escalated after 3-TYP treatment (Fig. 3E-F) while reversed after overexpression of Sirt3 (Fig. 3G-H). Conclusion Sirt 3 promotes renal gluconeogenesis in fibrotic kidneys through up-regulation of renal gluconeogenic enzyme PCK1 and FBP1 expression, which is associated with activation of renal metabolic transcription factors PGC-1α and FOXO1.

Cardiac diastolic maladaptation is associated with the severity of exercise intolerance in sickle cell anemia patients

This pilot study focusing on Sickle Cell Anemia (SCA) patients offers a comprehensive and integrative evaluation of respiratory, cardiovascular, hemodynamic, and metabolic variables during exercise. Knowing that diastolic dysfunction is frequent in this population, we hypothesize that a lack of cardiac adaptation through exercise might lead to premature increase in blood lactate concentrations in SCA patients, a potential trigger for acute disease complication. SCA patients were prospectively included in PHYSIO-EXDRE study and underwent a comprehensive stress test with a standardized incremental exercise protocol up to 4 mmol L−1 blood lactate concentration (BL4). Gas exchange, capillary lactate concentration and echocardiography were performed at baseline, during stress test (at ∼ 2 mmol L−1) and BL4. The population was divided into two groups and compared according to the median value of percentage of theoretical peak oxygen uptake (%V˙O2peakth\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\dot{\ ext{V}}\ ext{O}}_{2peakth}$$\\end{document}) at BL4. Twenty-nine patients were included (42 ± 12 years old, 48% of women). Most patients reached BL4 at low-intensity exercise [median value of predicted power output (W) was 37%], which corresponds to daily life activities. The median value of %V˙O2peakth\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\dot{\ ext{V}}\ ext{O}}_{2peakth}$$\\end{document} at BL4 was 39%. Interestingly, diastolic maladaptation using echocardiography during stress test along with hemoglobin concentration were independently associated to early occurrence of BL4. As BL4 occurs for low-intensity exercises, SCA patients may be subject to acidosis-related complications even during their daily life activities. Beyond assessing physical capacities, our study underlines that diastolic maladaptation during exercise is associated with an early increase in blood lactate concentration.

Features of the gas transport function of blood in hyperpigmentations of the skin

BACKGROUND: Acquired hyperpigmentation is widespread in the population and significantly affects the quality of life of the patients. It is known that one of the clinical signs of skin hyperpigmentation is localized hyperkeratosis in the lesion associated with a high level of cell proliferation and cell saturation with melanin. Cellular proliferation and hyperkeratosis are associated with increased local metabolism rates. AIM: Study of erythrocyte gas transport function in women with skin hyperpigmentation compared to the control group. MATERIALS AND METHODS: To achieve the objective, the concentrations of lactic acid, pyruvic acid and 2,3-diphosphoglycerate levels in venous blood erythrocytes were investigated. RESULTS: The phenomenon of skin hyperpigmentation is accompanied by a restructuring of blood cell metabolism aimed at preserving oxygen and energy homeostasis of skin structures. The obtained data indicate redistribution of oxygen in cellular structures and tissues, which is accompanied by a significant increase in lactate concentration and formation of local tissue hypoxia. CONCLUSION: The formation of skin pigmentation is considered as a physiological mechanism in response to inflammation, mainly associated with ultraviolet radiation. The general strategy of the course of the inflammatory process under normal regulation or dysregulation has similar features, but there are also differences. It seems necessary to further study systemic adaptation mechanisms in dysregulation and formation of skin hyperpigmentation.

Differences in lactate metabolism between middle- and long-distance runners

It is important for runners and coaches to figure out the characteristics of lactate metabolism in terms of planning the proper training. This study investigated the differences in lactate production and oxidation capacities between middle- and long-distance runners by using blood lactate concentration. We hypothesized that long-distance runners have greater capacity to oxidize lactate and middle-distance runners have greater capacity to produce lactate. In this study, 14 middle- and 14 long-distance male runners performed a multi-stage incremental test until exhaustion. Each running stage was 3-minute with 1-minute rest between stages. Blood lactate concentration was measured at rest and after each stage, and some metrics associated with runner’s capacity to oxidative lactate during moderate intensity exercise were calculated. The changes in blood lactate concentration measured after the final state of the test were modeled as a biexponential time function to evaluate lactate productive and oxidative capacities after high-intensity exercise. During moderate-intensity exercise, long-distance runners showed significant decrease in blood lactate concentrations during the first few stages of the test compared to rest, indicating greater oxidation of lactate than production of lactate during moderate intensity exercise (p&lt;0.05), while middle distance runners showed slight increase in blood lactate concentrations even for the first several stages. Middle-distance runners showed significantly higher amount of lactate produced (p&lt;0.05) and greater lactate oxidation during high-intensity exercise than those in long-distance runners (p&lt;0.01), suggesting that both lactate production and oxidation of middle-distance runners were greater than those of long-distance runners during high-intensity exercise. These results suggest that characteristics of lactate metabolism in middle- and long-distance runners depend partly on exercise intensity. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The Influence of Pedaling Frequency on Blood Lactate Accumulation in Cycling Sprints.

Anaerobic performance diagnostics in athletes relies on accurate measurements of blood lactate concentration and the calculation of blood lactate accumulation resulting from glycolytic processes. In this study, we investigated the impact of pedaling frequency on blood lactate accumulation during 10-second maximal isokinetic cycling sprints. Thirteen trained males completed five 10-second maximal isokinetic cycling sprints on a bicycle ergometer at different pedaling frequencies (90 rpm, 110 rpm, 130 rpm, 150 rpm, 170 rpm) with continuous power and frequency measurement. Capillary blood samples were taken pre-exercise and up to 30 minutes post-exercise to determine the maximum blood lactate concentration.Blood lactate accumulation was calculated as the difference between maximal post-exercise and pre-start blood lactate concentration. Repeated measurement ANOVA with Bonferroni-adjusted post hoc t-tests revealed significant progressive increases in maximal blood lactate concentration and accumulation with higher pedaling frequencies (p<0.001; η2+>+0.782).The findings demonstrate a significant influence of pedaling frequency on lactate accumulation, emphasizing its relevance in anaerobic diagnostics. Optimal assessment of maximal lactate formation rate is suggested to require a pedaling frequency of at least 130 rpm or higher, while determining metabolic thresholds using the maximal lactate formation rate may benefit from a slightly lower pedaling frequency.

Role of GPR81 in regulating intramuscular triglyceride storage during aerobic exercise in rats.

Lactate, a metabolite of exercise, plays a crucial role in the body. In these studies, we aimed to investigate the role of G protein-coupled receptor 81 (GPR81), a specific receptor for lactate, in regulating lipid storage in the gastrocnemius muscle of rats. To achieve this, we measured the impact of sodium 3-hydroxybutyrate (3-OBA) concentration and time on the cAMP-PKA signaling pathway in the gastrocnemius muscles ofrats. Our investigation involved determining the effects of administering 3-OBA at a concentration of 3 mmol L-1 just 15 min before exercise. As expected, exercise led to a notable increase in intramuscular lactate concentration in rats. However, injecting 3-OBA prior to exercise yielded intriguing results. It not only further augmented the cAMP-PKA signaling pathway but also boosted the expression of lipolysis-related proteins such as hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL). Simultaneously, it decreased the expression of fat-synthesizing proteins, including acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS), while increasing the protein expression of cytochrome c oxidase subunit Ⅳ(COX Ⅳ) and the activity of citrate synthetase (CS). Unfortunately, there was no significant change observed in intramuscular triglyceride (IMTG) content. In summary, our findings shed light on the role of lactate in partially regulating intramuscular triglycerides during exercise.

A57 LONG-TERM EXPOSURE TO ANTICANCER TREATMENTS INCREASES AUTOPHAGY IN ESOPHAGEAL SQUAMOUS CELL CARCINOMA

Abstract Background The most common type of esophageal cancer, esophageal squamous cell carcinoma (ESCC), has a 5-year survival rate of only 15%. This low survival rate is to some extent attributed to a high relapse rate, which is, in part, linked to the presence of cancer stem cells (CSC). CSC are a subpopulation of tumor cells that show reduced sensitivity to conventional anticancer therapies, increased potency and self-renewal capacities. With that in mind, ESCC cell lines were exposed in a prolonged manner to anticancer treatments (radiotherapy, 5-FU chemotherapy, and combined therapy) in our laboratory. As expected, an increase in the proportion of CSC (CD44highCD24high) was observed by flow cytometry following the treatments. In pursuit of innovative therapeutic approaches, we conducted an in-depth investigation of the proteomic profiles of these cell lines by mass spectrometry (MS), seeking to unveil novel biological mechanisms. Interestingly, many proteins associated with metabolism and autophagy were modulated. Several alterations were observed by a metabolomic approach as well, namely an increase in intracellular lactate concentration. Recently, a novel role for lactate has been described: lactylation, which is a post-translational modification. Lactylome of those cell lines revealed alteration in proteins related to autophagy and those results led to my research project. Aims Investigate the role of lactylation in autophagy of ESCC. Methods Human ESCC cell lines (including the cell lines exposed to anticancer treatments) will be used as cell culture models. Cell and organoid cultures, mass spectrometry, qPCR, WB, and proliferation assay were used. Results MS analysis of proteins related to autophagy (i.e. RAB1B, CK2, SNX6 et GABARAP) suggests differential regulation of autophagy in cell lines exposed to prolonged treatments. A strong contribution of the 5-FU treatment to the autophagic modification is observable in the double-treated cells. Thus, we confirmed an increase in the LC3BII/I ratio by WB in the cell lines exposed to anticancer treatments. LC3BII/I WB used in combination with Bafilomycin A1 treatment for inhibition of autophagosome and lysosome fusion is a commonly used read-out for autophagic flux. To further study the link between lactylation, autophagy and CSC, we screened 10 human ESCC cell lines for their LC3BII/I ratio. Four cell lines were selected: TE1, TE2, HCE4 and TE5. Using Bafilomycin A1, we confirmed that the autophagic flux in those cell lines was not blocked. Those cell lines will now be used to perform lactylome analysis of sorted CSC cells. Conclusions In brief, our results showed that the autophagic flux is increased in cells exposed to prolonged treatments. This suggests that autophagy could play a role in ESCC response to treatment. Funding Agencies CIHRTRIANGLE, Chaires de recherche du Canada, CRCHUS, Université de Sherbrooke

Calculation of a conversion factor for estimating the glycolytic contribution in exercise from post-exercise blood lactate concentration.

Purpose: Often, the glycolytic contribution in a bout of heavy or severe intensity exercise is estimated by multiplying the increase in blood lactate concentration above resting levels that is engendered by the exercise (in mM) by 3.3 (or 3) mL·kg-1 per mM. Our purpose was to verify the value of this conversion factor, using methods that were completely different from those of the original studies. Methods: Six women (mean ± SD), age, 23 ± 1year; VO2max, 46 ± 4mL·kg-1·min-1) and three men (23 ± 0years; 54 ± 8mL·kg-1·min-1) completed 6min of heavy intensity exercise in conditions of normoxia and hypoxia (FIO2, ∼12%). VO2 was measured throughout the exercise and 7min of recovery. The increase in glycolytic contribution was estimated as the reduction in aerobic contribution in hypoxia, after correction for the effects of hypoxia on the oxygen demand and on the contribution from phosphocreatine. The peak post-exercise blood lactate concentration was measured in fingerstick blood samples. Results: The ratio between the increase in estimated glycolytic contribution (in mL·kg-1) in hypoxia and the increase in peak blood lactate concentration (in mM) yielded an oxygen equivalent of 3.4 ± 0.4mL·kg-1 per mM (range, 2.6mL·kg-1 per mM to 4.0mL·kg-1 per mM) for cycle ergometer exercise. Conclusion: These results generally support the use of a common conversion factor to calculate the glycolytic contribution from post-exercise blood lactate concentrations. However, there is some inter-individual variability in the conversion factor.

Amifostine ameliorates bleomycin-induced murine pulmonary fibrosis via NAD+/SIRT1/AMPK pathway-mediated effects on mitochondrial function and cellular metabolism

BackgroundIdiopathic pulmonary fibrosis (IPF) is a devastating chronic lung disease characterized by irreversible scarring of the lung parenchyma. Despite various interventions aimed at mitigating several different molecular aspects of the disease, only two drugs with limited clinical efficacy have so far been approved for IPF therapy.ObjectiveWe investigated the therapeutic efficacy of amifostine, a detoxifying drug clinically used for radiation-caused cytotoxicity, in bleomycin-induced murine pulmonary fibrosis.MethodsC57BL6/J mice were intratracheally instilled with 3 U/kg of bleomycin. Three doses of amifostine (WR-2721, 200 mg/kg) were administered intraperitoneally on days 1, 3, and 5 after the bleomycin challenge. Bronchoalveolar lavage fluid (BALF) was collected on day 7 and day 21 for the assessment of lung inflammation, metabolites, and fibrotic injury. Human fibroblasts were treated in vitro with transforming growth factor beta 1 (TGF-β1), followed by amifostine (WR-1065, 1–4 µg/mL) treatment. The effects of TGF-β1 and amifostine on the mitochondrial production of reactive oxygen species (ROS) were assessed by live cell imaging of MitoSOX. Cellular metabolism was assessed by the extracellular acidification rate (ECAR), the oxygen consumption rate (OCR), and the concentrations of various energy-related metabolites as measured by mass spectrum (MS). Western blot analysis was performed to investigate the effect of amifostine on sirtuin 1 (SIRT1) and adenosine monophosphate activated kinase (AMPK).ResultsThree doses of amifostine significantly attenuated lung inflammation and pulmonary fibrosis. Pretreatment and post-treatment of human fibroblast cells with amifostine blocked TGF-β1-induced mitochondrial ROS production and mitochondrial dysfunction in human fibroblast cells. Further, treatment of fibroblasts with TGF-β1 shifted energy metabolism away from mitochondrial oxidative phosphorylation (OXPHOS) and towards glycolysis, as observed by an altered metabolite profile including a decreased ratio of NAD + /NADH and increased lactate concentration. Treatment with amifostine significantly restored energy metabolism and activated SIRT1, which in turn activated AMPK. The activation of AMPK was required to mediate the effects of amifostine on mitochondrial homeostasis and pulmonary fibrosis. This study provides evidence that repurposing of the clinically used drug amifostine may have therapeutic applications for IPF treatment.ConclusionAmifostine inhibits bleomycin-induced pulmonary fibrosis by restoring mitochondrial function and cellular metabolism.

Molecular mechanism of circHIPK3 in mitochondrial function in septic acute kidney injury.

Cell senescence, glycolysis, and mitochondrial deficit jointly regulate the development of septic acute kidney injury (SAKI). This study aimed to explore the role of circular RNA HIPK3 (circHIPK3) in mitochondrial function in SAKI. The SAKI mouse model was established by Candida albicans infection, followed by Western blot assay, measurements of serum lactate, and adenosine triphosphate (ATP), 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimi-dazolylcarbocyanine iodide (JC-1) staining and flow cytometry. Human renal tubular epithelial cells were treated with lipopolysaccharide to establish the SAKI cell model, followed by cell counting kit-8 assay, tests of hexokinase activity, lactate production, oxygen consumption rate, extracellular acidification rate, ATP, and JC-1 staining, and Western blot assay. The roles of mitochondrial pyruvate carrier 1 (MPC1) were validated by kidney function tests, hematoxylin and eosin staining, periodic acid-Schiff staining, and SA-β-gal staining. circHIPK3 downregulation reduced glycolysis and mitochondrial dysfunction both in vivo and in vitro through the microRNA (miR)-148b-3p/DNMT1/3a/Klotho axis. Inhibition of miR-148b-3p or Klotho increased glycolysis and mitochondrial dysfunction. Knockdown of MPC1 increased lactate content and decreased ATP levels and MMP both in vivo and in vitro. Collectively, circHIPK3, in concert with the miR-148b-3p/DNMT1/3a/Klotho axis, increased glycolysis, and inhibited the negative regulation of lactate production by MPC1, and aggravated mitochondrial dysfunction and cell senescence in SAKI.

Recycled UHT Milk Carton Cellulose Substrate for Colorimetric and Electrochemical Sensor of Lactate

Recycled cellulose prepared from UHT milk carton waste was employed as a novel substrate for colorimetric and electrochemical lactate sensors to evaluate the milk quality. The cellulose is initially extracted by chemical method (alkali and bleach treatment) to prepare the dual-sensing substrate. For colorimetric sensor, an enzyme immobilization was performed on the recycled cellulose substrate prior to enhancing specificity for lactate detection. Subsequently, the recycled cellulose substrate was dipped in an aluminum solution extracted from aluminum foil from the packaging to create a conductive working electrode with improved surface roughness compared with recycled cellulose substrate, confirmed by atomic force microscopy. For the physical and chemical characterization, scanning electron micrograph demonstrated 3D fibrous network with the porous in between, and X-ray photoelectron spectroscopy presented the binding energy with the Al-O peak at 73.256 eV, verifying the existence of aluminum on the recycled cellulose substrate after surface modification. For the sensing performance, the colorimetric sensor provides the increasing purpleness intensity with the increment of lactate concentration, while the aluminum-modified recycled cellulose substrate exhibited the increased current response upon the increased lactate concentration. Furthermore, this dual-lactate sensor can offer a linearity of 0.125-2 M, covering a cut-off lactate level (1.0 M) for milk spoilage. Ultimately, this sensor is successfully utilized for lactate determination in real milk samples, showing its high efficiency as an alternative platform for milk quality evaluation.

BLAST INJURI. ANESTHESIA AND INTRAOPERATIVE INTENSIVE CARE AT THE EARLY HOSPITAL STAGE (ADVANCE NOTICE)

Summary. Explosive injury is a combat multifactorial injury that occurs as a result of the combined damaging effect on the human body of a shock wave, gas jets, fire, toxic products of explosion and combustion, ammunition casing fragments, secondary projectiles. The hostilities taking place in Ukraine present many questions to anesthesiologists regarding the provision of medical care to victims of blast injuries. This type of injury is often associated with damage to 2-4 anatomical sites and sometimes more. Moreover, most of the hospital care is provided in civilian hospitals located close to fighting.&#x0D; The aim of study. The choice of anesthesia technology and intraoperative intensive therapy in victims of explosive trauma depending on the severity of the explosive trauma and the condition of the patients.&#x0D; Material and method. During the period March-December 2022, 226 (195 men, 31 women) patients of explosive injuries were admitted to the Zaporizhzhya Regional Clinical Hospital and assessed according to the GKO scale (standardized system for assessing the severity of injuries and the condition of patients.&#x0D; The results. Before the operation, there was normotension and moderate tachycardia. However, in 25 patients, the systolic blood pressure was less than 90 mm Hg, which required the use of sympathomimetics and infusion therapy with crystalloids and colloids. During the operation, sympathomimetics continued to be used in 42 patients. Norepinephrine was used in 37 patients in a dose of 0.1 to 0.4 μg/kg/min. Phenylephrine – in 5 patients in bolus doses of 20-100 μg.&#x0D; The indicators of systolic, diastolic, pulse, mean arterial pressure and heart rate at the stage of completion of the operation did not differ significantly from the initial ones. Before the operation, the patients had subcompensated metabolic and respiratory acidosis, hyperoxemia, and increased lactate concentration. At the stage of the operation, the phenomenon of metabolic acidosis increased, as evidenced by a significant increase in the BE indicator. Respiratory acidosis and hyperoxemia persisted. The concentration of lactate in the blood decreased significantly, on average by 21 %, but on average was (4.1±0.1) mmol/l.&#x0D; Conclusion. Assessing the severity of the patients on the GKO scale allows you to choose the anesthesia technology considering the influence of the drugs used for anesthesia on hemodynamics. At the stages of treatment of the patients of the blast trauma, it was possible to maintain normotension. Mixed decompensated acidosis and increased lactate at the end of the operation indicate oxygen debt.

PARAMETERS OF ENERGY METABOLISM AND ADENYLATE SYSTEM OF MYTILUS GALLOPROVINCIALIS TISSUES (LAMARCK. 1819) IN CONDITIONS OF MODERATE HYPOXIA

The effect of moderate hypoxia on the processes of energy metabolism in the tissues (gills, hepatopancreas) of the Mediterranean mussel (Mytilus galloprovincialis, Lamarck, 1819) was studied experimentally. The control group of mollusks contained 6.8–6.9 mgO2 l–1, the experimental group at 1.9–2.0 mgO2 l–1. In both cases, the water temperature was 22 ± 1°C, the salinity was 17–18‰. The exposition – 72 hours. The oxygen content in the water was lowered by bubbling with nitrogen gas for 4–5 hours. In conditions of moderate hypoxia, a complex of reactions aimed at maintaining the energy status of tissues developed in the body of the Mediterranean mussel. Aerobic processes were clearly limited, as evidenced by a decrease in succinate dehydrogenase (SDH) activity. At the same time, the processes of anaerobic glycolysis intensified. The activity of aldolase, malate dehydrogenase (MDH) increased, the content of pyruvate in tissues increased. This was not accompanied by an increase in lactate dehydrogenase (LDH) activity and an increase in lactate content. The tissues retained their original energy status. The content of the ATP fraction remained at the level of control values, which reflected the adaptive orientation of the reorganization of tissue metabolism. The ability of hepatopancreas to accumulate ADP and AMP fractions from circulation systems under experimental hypoxic load was noted.