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Robergs R, O'Malley B, Torrens S. The missing hydrogen ion, Part-3: Science and the human flaws that compromise it. SPORTS MEDICINE AND HEALTH SCIENCE 2024; 6:193-199. [PMID: 38708325 PMCID: PMC11067858 DOI: 10.1016/j.smhs.2024.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 03/05/2024] [Accepted: 03/19/2024] [Indexed: 05/07/2024] Open
Abstract
The purpose of this research was to use a historical method and core principles from scientific philosophy to explain why mistakes were made in the development of the lactic acidosis construct. On a broader scope, this research explains what science is, why some scientists despite good intention, often get it wrong, and why it takes so long (decades) to correct these errors. Science is a human behaviour that consists of the identification of a problem based on the correct application of prior knowledge, the development of a method to best resolve or test the problem, completion of these methods to acquire results, and then a correct interpretation of the results. If these steps are done correctly there is an increased probability (no guarantee) that the outcome is likely to be correct. Thomas Kuhn proposed that you can understand what science is from how it has been performed, and from his essays he revealed a very dysfunctional form of science that he called 'normal' (due the preponderance of its presence) science. Conversely, Karl Popper was adamant that the practice of 'normal' science revealed numerous flaws that deviate from fundamental principles that makes science, science. Collectively, the evidence reveals that within the sports medicine and health sciences, as with all disciplines, errors in science are more frequent than you might expect. There is an urgent need to improve how we educate and train scientists to prevent the pursuit of 'normal' science and the harm it imparts on humanity.
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Affiliation(s)
- Robert Robergs
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Bridgette O'Malley
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Sam Torrens
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
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DiNuzzo M, Dienel GA, Behar KL, Petroff OA, Benveniste H, Hyder F, Giove F, Michaeli S, Mangia S, Herculano-Houzel S, Rothman DL. Neurovascular coupling is optimized to compensate for the increase in proton production from nonoxidative glycolysis and glycogenolysis during brain activation and maintain homeostasis of pH, pCO 2, and pO 2. J Neurochem 2024; 168:632-662. [PMID: 37150946 PMCID: PMC10628336 DOI: 10.1111/jnc.15839] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 04/22/2023] [Accepted: 05/02/2023] [Indexed: 05/09/2023]
Abstract
During transient brain activation cerebral blood flow (CBF) increases substantially more than cerebral metabolic rate of oxygen consumption (CMRO2) resulting in blood hyperoxygenation, the basis of BOLD-fMRI contrast. Explanations for the high CBF versus CMRO2 slope, termed neurovascular coupling (NVC) constant, focused on maintenance of tissue oxygenation to support mitochondrial ATP production. However, paradoxically the brain has a 3-fold lower oxygen extraction fraction (OEF) than other organs with high energy requirements, like heart and muscle during exercise. Here, we hypothesize that the NVC constant and the capillary oxygen mass transfer coefficient (which in combination determine OEF) are co-regulated during activation to maintain simultaneous homeostasis of pH and partial pressure of CO2 and O2 (pCO2 and pO2). To test our hypothesis, we developed an arteriovenous flux balance model for calculating blood and brain pH, pCO2, and pO2 as a function of baseline OEF (OEF0), CBF, CMRO2, and proton production by nonoxidative metabolism coupled to ATP hydrolysis. Our model was validated against published brain arteriovenous difference studies and then used to calculate pH, pCO2, and pO2 in activated human cortex from published calibrated fMRI and PET measurements. In agreement with our hypothesis, calculated pH, pCO2, and pO2 remained close to constant independently of CMRO2 in correspondence to experimental measurements of NVC and OEF0. We also found that the optimum values of the NVC constant and OEF0 that ensure simultaneous homeostasis of pH, pCO2, and pO2 were remarkably similar to their experimental values. Thus, the high NVC constant is overall determined by proton removal by CBF due to increases in nonoxidative glycolysis and glycogenolysis. These findings resolve the paradox of the brain's high CBF yet low OEF during activation, and may contribute to explaining the vulnerability of brain function to reductions in blood flow and capillary density with aging and neurovascular disease.
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Affiliation(s)
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205 USA
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, NM, 87131 USA
| | - Kevin L Behar
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, 06511 USA
| | - Ognen A Petroff
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, 06511 USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale University, New Haven, CT, 06520 USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520 USA
| | - Fahmeed Hyder
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520 USA
- Department of Radiology, Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, 06520 USA
| | - Federico Giove
- Centro Ricerche Enrico Fermi, Rome, RM, 00184 Italy
- Fondazione Santa Lucia IRCCS, Rome, RM, 00179 Italy
| | - Shalom Michaeli
- Department of Radiology, Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, 55455 USA
| | - Silvia Mangia
- Department of Radiology, Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, 55455 USA
| | - Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, TN
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN
| | - Douglas L Rothman
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520 USA
- Department of Radiology, Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, 06520 USA
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Robergs R, O’Malley B, Torrens S, Siegler J. The missing hydrogen ion, part-2: Where the evidence leads to. SPORTS MEDICINE AND HEALTH SCIENCE 2024; 6:94-100. [PMID: 38463661 PMCID: PMC10918345 DOI: 10.1016/j.smhs.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 12/19/2023] [Accepted: 01/09/2024] [Indexed: 03/12/2024] Open
Abstract
The purpose of this manuscript was to present the evidence for why cells do not produce metabolic acids. In addition, evidence that opposes common viewpoints and arguments used to support the cellular production of lactic acid (HLa) or liver keto-acids have been provided. Organic chemistry reveals that many molecules involved in cellular energy catabolism contain functional groups classified as acids. The two main acidic functional groups of these molecules susceptible to ∼H+ release are the carboxyl and phosphoryl structures, though the biochemistry and organic chemistry of molecules having these structures reveal they are produced in a non-acidic ionic (negatively charged) structure, thereby preventing pH dependent ∼H+ release. Added evidence from the industrial production of HLa further reveals that lactate (La-) is produced followed by an acidification step that converts La- to HLa due to pH dependent ∼H+ association. Interestingly, there is a plentiful list of other molecules that are classified as acids and compared to HLa have similar values for their H+ dissociation constant (pKd). For many metabolic conditions, the cumulative turnover of these molecules is far higher than for La-. The collective evidence documents the non-empirical basis for the construct of the cellular production of HLa, or any other metabolic acid.
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Affiliation(s)
- Robert Robergs
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Bridgette O’Malley
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Sam Torrens
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Jason Siegler
- ASU Health Futures Center, College of Health Solutions, Arizona State University, 6161 East Mayo Blvd, Phoenix, 85054, Arizona, USA
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Robergs R, O'Malley B, Torrens S, Siegler J. The missing hydrogen ion, part-1: Historical precedents vs. fundamental concepts. SPORTS MEDICINE AND HEALTH SCIENCE 2023; 5:336-343. [PMID: 38314048 PMCID: PMC10831364 DOI: 10.1016/j.smhs.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 10/04/2023] [Accepted: 10/30/2023] [Indexed: 02/06/2024] Open
Abstract
The purpose of this review and commentary was to provide an historical and evidence-based account of organic acids and the biochemical and organic chemistry evidence for why cells do not produce metabolites that are acids. The scientific study of acids has a long history dating to the 16th and 17th centuries, and the definition of an acid was proposed in 1884 as a molecule that when in an aqueous solution releases a hydrogen ion (H+). There are three common ionizable functional groups for molecules classified as acids: 1) the carboxyl group, 2) the phosphoryl group and 3) the amine group. The propensity by which a cation will associate or dissociate with a negatively charged atom is quantified by the equilibrium constant (Keq) of the dissociation constant (Kd) of the ionization (Keq = Kd), which for lactic acid (HLa) vs. lactate (La-) is expressed as: K e q = K d = [ H + ] [ L a - ] [ H L a ] = 4 677.351 4 (ionic strength = 0.01 Mol⋅L-1, T = 25 °C). The negative log10 of the dissociation pKd reveals the pH at which half of the molecules are ionized, which for HLa = 3.67. Thus, knowing the pKd and the pH of the solution at question will reveal the extent of the ionization vs. acidification of molecules that are classified as acids.
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Affiliation(s)
- Robert Robergs
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Bridgette O'Malley
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Sam Torrens
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia
| | - Jason Siegler
- ASU Health Futures Center, College of Health Solutions, Arizona State University, 6161 East Mayo Blvd, Phoenix, 85054, Arizona, USA
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Torrens SL, Robergs RA, Curry SC, Nalos M. The Computational Acid-Base Chemistry of Hepatic Ketoacidosis. Metabolites 2023; 13:803. [PMID: 37512510 PMCID: PMC10383603 DOI: 10.3390/metabo13070803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/08/2023] [Accepted: 06/25/2023] [Indexed: 07/30/2023] Open
Abstract
Opposing evidence exists for the source of the hydrogen ions (H+) during ketoacidosis. Organic and computational chemistry using dissociation constants and alpha equations for all pertinent ionizable metabolites were used to (1) document the atomic changes in the chemical reactions of ketogenesis and ketolysis and (2) identify the sources and quantify added fractional (~) H+ exchange (~H+e). All computations were performed for pH conditions spanning from 6.0 to 7.6. Summation of the ~H+e for given pH conditions for all substrates and products of each reaction of ketogenesis and ketolysis resulted in net reaction and pathway ~H+e coefficients, where negative revealed ~H+ release and positive revealed ~H+ uptake. Results revealed that for the liver (pH = 7.0), the net ~H+e for the reactions of ketogenesis ending in each of acetoacetate (AcAc), β-hydroxybutyrate (β-HB), and acetone were -0.9990, 0.0026, and 0.0000, respectively. During ketogenesis, ~H+ release was only evident for HMG CoA production, which is caused by hydrolysis and not ~H+ dissociation. Nevertheless, there is a net ~H+ release during ketogenesis, though this diminishes with greater proportionality of acetone production. For reactions of ketolysis in muscle (pH = 7.1) and brain (pH = 7.2), net ~H+ coefficients for β-HB and AcAc oxidation were -0.9649 and 0.0363 (muscle), and -0.9719 and 0.0291 (brain), respectively. The larger ~H+ release values for β-HB oxidation result from covalent ~H+ release during the oxidation-reduction. For combined ketogenesis and ketolysis, which would be the metabolic condition in vivo, the net ~H+ coefficient depends once again on the proportionality of the final ketone body product. For ketone body production in the liver, transference to blood, and oxidation in the brain and muscle for a ratio of 0.6:0.2:0.2 for β-HB:AcAc:acetone, the net ~H+e coefficients for liver ketogenesis, blood transfer, brain ketolysis, and net total (ketosis) equate to -0.1983, -0.0003, -0.2872, and -0.4858, respectively. The traditional theory of ketone bodies being metabolic acids causing systemic acidosis is incorrect. Summation of ketogenesis and ketolysis yield H+ coefficients that differ depending on the proportionality of ketone body production, though, in general, there is a small net H+ release during ketosis. Products formed during ketogenesis (HMG-CoA, acetoacetate, β-hydroxybutyrate) are created as negatively charged bases, not acids, and the final ketone body, acetone, does not have pH-dependent ionizable groups. Proton release or uptake during ketogenesis and ketolysis are predominantly caused by covalent modification, not acid dissociation/association. Ketosis (ketogenesis and ketolysis) results in a net fractional H+ release. The extent of this release is dependent on the final proportionality between acetoacetate, β-hydroxybutyrate, and acetone.
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Affiliation(s)
- Samuel L Torrens
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology, Kelvin Grove, QLD 4058, Australia
| | - Robert A Robergs
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology, Kelvin Grove, QLD 4058, Australia
| | - Steven C Curry
- Department of Medical Toxicology, Banner-University Medical Center Phoenix, Phoenix, AZ 85006, USA
| | - Marek Nalos
- Intensive Care Medicine, Goulburn Hospital, Goulburn, NSW 2580, Australia
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Carneiro MDD, García-Mesa S, Sampaio LA, Planas M. Implications of Salinity and Acidic Environments on Fitness and Oxidative Stress Parameters in Early Developing Seahorses Hippocampus reidi. Animals (Basel) 2022; 12:ani12223227. [PMID: 36428453 PMCID: PMC9686857 DOI: 10.3390/ani12223227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
Water acidification affects aquatic species, both in natural environmental conditions and in ex situ rearing production systems. The chronic effects of acidic conditions (pH 6.5 vs. pH 8.0) in seahorses (Hippocampus spp.) are not well known, especially when coupled with salinity interaction. This study investigated the implications of pH on the growth and oxidative stress in the seahorse Hippocampus reidi (Ginsburg, 1933), one of the most important seahorse species in the ornamental trade. Two trials were carried out in juveniles (0-21 and 21-50 DAR-days after the male's pouch release) reared under acid (6.5) and control (8.0) pH, both in brackish water (BW-salinity 11) and seawater (SW-salinity 33). In the first trial (0-21 DAR), there was no effect of pH on the growth of seahorses reared in SW, but the survival rate was higher for juveniles raised in SW at pH 6.5. However, the growth and survival of juveniles reared in BW were impaired at pH 6.5. Compared to SW conditions, the levels of superoxide dismutase and DT-diaphorase, as well as the oxidative stress index, increased for juveniles reared in BW. In the second trial, seahorse juveniles were reared in SW at pH 8.0, and subsequently kept for four weeks (from 21 to 50 DAR) at pH 6.5 and 8.0. The final survival rates and condition index were similar in both treatments. However, the growth under acidic conditions was higher than at pH 8.0. In conclusion, this study highlights that survival, growth, and oxidative status condition was enhanced in seahorse juveniles reared in SW under acidic conditions (pH = 6.5). The concurrent conditions of acidic pH (6.5) and BW should be avoided due to harmful effects on the fitness and development of seahorse juveniles.
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Affiliation(s)
- Mario D. D. Carneiro
- Department of Ecology and Marine Resources, Institute of Marine Research (CSIC), 36208 Vigo, Spain
- Laboratório de Piscicultura Estuarina e Marinha, Instituto de Oceanografia, Universidade Federal do Rio Grande–FURG, Rio Grande 96210-030, Brazil
- Correspondence: (M.D.D.C.); (M.P.); Tel.: +34-986214457 (M.P.)
| | - Sergio García-Mesa
- Department of Zoology, University of Granada, Campus Universitario de Fuentenueva, 18071 Granada, Spain
| | - Luis A. Sampaio
- Laboratório de Piscicultura Estuarina e Marinha, Instituto de Oceanografia, Universidade Federal do Rio Grande–FURG, Rio Grande 96210-030, Brazil
| | - Miquel Planas
- Department of Ecology and Marine Resources, Institute of Marine Research (CSIC), 36208 Vigo, Spain
- Correspondence: (M.D.D.C.); (M.P.); Tel.: +34-986214457 (M.P.)
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Abstract
The hydrogen ion concentration ([H+]) in intracellular cytoplasmic fluid (ICF) must be maintained in a narrow range in all species for normal protein functions. Thus, mechanisms regulating ICF are of fundamental biological importance. Studies on the regulation of ICF [H+] have been hampered by use of pH notation, failure to consider the roles played by differences in the concentration of strong ions (strong ion difference, SID), the conservation of mass, the principle of electrical neutrality, and that [H+] and bicarbonate ions [HCO3-] are dependent variables. This argument is based on the late Peter Stewart's physical-chemical analysis of [H+] regulation reported in this journal nearly forty years ago (Stewart. 1983. Can. J. Physiol. Pharmacol. 61: 1444-1461. Doi:10.1139/y83-207). We start by outlining the principles of Stewart's analysis and then provide a general understanding of its significance for regulation of ICF [H+]. The system may initially appear complex, but it becomes evident that changes in SID dominate regulation of [H+]. The primary strong ions are Na+, K+, and Cl-, and a few organic strong anions. The second independent variable, partial pressure of carbon dioxide (PCO2), can easily be assessed. The third independent variable, the activity of intracellular weak acids ([Atot]), is much more complex but largely plays a modifying role. Attention to these principles will potentially provide new insights into ICF pH regulation.
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Affiliation(s)
- Sheldon Magder
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
| | - Alexandr Magder
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
| | - Gordan Samoukovic
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada
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Robergs RA. Quantifying H + exchange from muscle cytosolic energy catabolism using metabolite flux and H + coefficients from multiple competitive cation binding: New evidence for consideration in established theories. Physiol Rep 2021; 9:e14728. [PMID: 33904663 PMCID: PMC8077081 DOI: 10.14814/phy2.14728] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 10/18/2020] [Accepted: 01/03/2021] [Indexed: 11/30/2022] Open
Abstract
The purpose of this investigation was to present calculations of fractional H+ exchange (~H+e ) from the chemical reactions of non-mitochondrial energy catabolism. Data of muscle pH and metabolite accumulation were based on published research for intense exercise to contractile failure within ~3 min, from which capacities and time profiles were modeled. Data were obtained from prior research for multiple competitive cation dissociation constants of metabolites and the chemical reactions of non-mitochondrial energy catabolism, and pH dependent calculations of ~H+e from specific chemical reactions. Data revealed that the 3 min of intense exercise incurred a total ATP turnover of 142.5 mmol L-1 , with a total intramuscular ~H+ exchange (-'ve = release) of -187.9 mmol L-1 . Total ~H+ metabolic consumption was 130.6 mmol L-1 , revealing a net total ~H+e (~H+te ) of -57.3 mmol L-1 . Lactate production had a ~H+te of 44.2 mmol L-1 (for a peak accumulation = 45 mmol L-1 ). The net ~H+te for the sum of the CK, AK, and AMPD reactions was 36.33 mmol L-1 . The ~H+te from ATP turnover equaled -47.5 mmol L-1 . The total ~H+ release to lactate ratio was 4.3 (187.9/44). Muscle ~H+ release during intense exercise is up to ~4-fold larger than previously assumed based on the lactic acid construct.
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Affiliation(s)
- Robert A. Robergs
- School of Exercise and Nutrition SciencesFaculty of HealthQueensland University of TechnologyKelvin GroveQLDAustralia
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Franco GS, Noronha NY, Oliveira BA, Ferreira FC, Pinto AP, Brandao CF, Papoti M, Nonino CB. Beta-alanine fails to improve on 5000 m running time despite increasing PAT1 expression in long-distance runners. J Sports Med Phys Fitness 2020; 61:1605-1612. [PMID: 33305552 DOI: 10.23736/s0022-4707.20.11946-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Beta-alanine has become a dietary supplement widely used by athletes due to its ergogenic effect. However, there is still no consensus on the performance benefit of beta-alanine on exercise lasting longer than ten minutes. The present study aimed to evaluate the effect of beta-alanine supplementation on running performance and the expression of TauT and PAT1. METHODS This double-blind, randomized study enrolled 16 long-distance runners (37±8 years) who were randomly allocated to two groups: placebo (PLA) and beta-alanine (BA) (4.8 g/day 1) for four weeks. Maximal oxygen consumption, anthropometry, body composition, and food intake were determined. Before and after the intervention, the athletes undertook a 5000 m running time trial. Venous blood (TauT and PAT1 expressions) and ear lobe capillary blood (lactate) collected before and after exercise. Between tests, we monitored the training variables. RESULTS The results were analyzed by t-tests and an ANOVA of repeated measures, with Sidak's post hoc (P<0.05). PLA exhibited lower body fat than BA (8.7±2.2 vs. 11.5±2.8%, P=0.04). After supplementation, there was an increase in PAT1 expression in BA when compared to PLA (1.17±0.47 vs. 0.77±0.18, P=0.04). No significant differences were shown for the 5000 m running time in PLA (PRE: 1128±72; POST: 1123±72s) and BA (PRE: 1107±95; POST: 1093±86s). CONCLUSIONS Although beta-alanine supplementation increased PAT1 expression, there was no statistically significant improvement in 5000 m running performance. However, individual responses should be considered as the BA showed a higher delta than the PLA.
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Affiliation(s)
- Gabriel S Franco
- Department of Internal Medicine, Laboratory of Nutrigenomics Studies, Faculty of Medicine, University of São Paulo, Ribeirão Preto, Brazil - .,Departament of Nutrition, University of Franca, Franca, Brazil -
| | - Natália Y Noronha
- Department of Internal Medicine, Laboratory of Nutrigenomics Studies, Faculty of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Bruno A Oliveira
- Department of Internal Medicine, Laboratory of Nutrigenomics Studies, Faculty of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Flávia C Ferreira
- Department of Internal Medicine, Laboratory of Nutrigenomics Studies, Faculty of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Ana P Pinto
- Ribeirão Preto School of Physical Education and Sport, Laboratory of Exercise Physiology and Metabolism, University of São Paulo, Ribeirão Preto, Brazil
| | - Camila F Brandao
- Division of Nutrology, Department of Internal Medicine, Faculty of Medicine, University of São Paulo, Ribeirão Preto, Brazil.,State University of Minas Gerais, Divinópolis, Brazil
| | - Marcelo Papoti
- Ribeirão Preto School of Physical Education and Sport, Laboratory of Water Activities, University of São Paulo, Ribeirão Preto, Brazil
| | - Carla B Nonino
- Department of Internal Medicine, Laboratory of Nutrigenomics Studies, Faculty of Medicine, University of São Paulo, Ribeirão Preto, Brazil
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Wernly B, Heramvand N, Masyuk M, Rezar R, Bruno RR, Kelm M, Niederseer D, Lichtenauer M, Hoppe UC, Bakker J, Jung C. Acidosis predicts mortality independently from hyperlactatemia in patients with sepsis. Eur J Intern Med 2020; 76:76-81. [PMID: 32143899 DOI: 10.1016/j.ejim.2020.02.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 02/15/2020] [Accepted: 02/24/2020] [Indexed: 02/07/2023]
Abstract
RATIONALE AND OBJECTIVES Acidosis and hyperlactatemia predict outcome in critically ill patients. We assessed BE and pH for risk prediction capabilities in a sub-group of septic patients in the MIMIC-III database. METHODS Associations with mortality were assessed by logistic regression analysis in 5586 septic patients. Baseline parameters, lactate concentrations, pH, and BE were analyzed at baseline and after 6 hours. MEASUREMENTS AND MAIN RESULTS We combined acidosis (defined as either BE ≤-6 and/or pH ≤7.3) and hyperlactatemia and split the cohort into three subgroups: low-risk (no acidosis and lactate <2.3 mmol/L; n = 2294), medium-risk (either acidosis or lactate >2.3 mmol/L; n = 2125) and high-risk (both acidosis and lactate >2.3 mmol/L; n = 1167). Mortality was 14%, 20% and 38% (p<0.001) in low-risk, medium-risk and high-risk patients, respectively. The predictiveness of this model (AUC 0.63 95%CI 0.61-0.65) was higher compared to acidosis (AUC 0.59 95%CI 0.57-0.61; p<0.001) and lactate >2.3 mmol/L (AUC 0.60 95%CI 0.58-0.62; p<0.001) alone. Hyperlactatemia alone was only moderately predictive for acidosis (AUC 0.60 95%CI 0.59-0.62). CONCLUSIONS Acidosis and hyperlactatemia can occur independently to a certain degree. Combining acidosis and hyperlactatemia in a model yielded higher predictiveness for ICU-mortality. Septic patients with acidosis should be treated even more aggressively in the future.
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Affiliation(s)
- Bernhard Wernly
- Clinic of Internal Medicine II, Department of Cardiology, Paracelsus Medical University of Salzburg, Salzburg, Austria; Division of Cardiology, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Nadia Heramvand
- Division of Cardiology, Pulmonology and Vascular Medicine, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Maryna Masyuk
- Division of Cardiology, Pulmonology and Vascular Medicine, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Richard Rezar
- Clinic of Internal Medicine II, Department of Cardiology, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | - Raphael Romano Bruno
- Division of Cardiology, Pulmonology and Vascular Medicine, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Malte Kelm
- Division of Cardiology, Pulmonology and Vascular Medicine, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; CARID, Cardiovascular Research Institute Düsseldorf, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - David Niederseer
- Department of Cardiology, University Heart Center Zurich, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Michael Lichtenauer
- Clinic of Internal Medicine II, Department of Cardiology, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | - Uta C Hoppe
- Clinic of Internal Medicine II, Department of Cardiology, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | - Jan Bakker
- Department of Intensive Care Adults, Erasmus MC University Medical Center, Rotterdam, The Netherlands; Department of Pulmonology and Critical Care, New York University Medical Center, New York, USA; Department of Pulmonology and Critical Care, Columbia University Medical Center, New York, USA; Department of Intensive Care, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Christian Jung
- Division of Cardiology, Pulmonology and Vascular Medicine, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany.
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Nalos M, Robergs R. Understanding Hyperlactatemia in Sepsis: Are We There Yet? Am J Respir Crit Care Med 2020; 200:1069-1070. [PMID: 31206309 PMCID: PMC6794111 DOI: 10.1164/rccm.201905-0962le] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Marek Nalos
- Charles UniversityPlzen, Czech Republic.,University of SydneySydney, Australiaand
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Bisetto S, Wright MC, Nowak RA, Lepore AC, Khurana TS, Loro E, Philp NJ. New Insights into the Lactate Shuttle: Role of MCT4 in the Modulation of the Exercise Capacity. iScience 2019; 22:507-518. [PMID: 31837519 PMCID: PMC6920289 DOI: 10.1016/j.isci.2019.11.041] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/30/2019] [Accepted: 11/22/2019] [Indexed: 12/31/2022] Open
Abstract
Lactate produced by muscle during high-intensity activity is an important end product of glycolysis that supports whole body metabolism. The lactate shuttle model suggested that lactate produced by glycolytic muscle fibers is utilized by oxidative fibers. MCT4 is a proton coupled monocarboxylate transporter preferentially expressed in glycolytic muscle fibers and facilitates the lactate efflux. Here we investigated the exercise capacity of mice with disrupted lactate shuttle due to global deletion of MCT4 (MCT4-/-) or muscle-specific deletion of the accessory protein Basigin (iMSBsg-/-). Although MCT4-/- and iMSBsg-/- mice have normal muscle morphology and contractility, only MCT4-/- mice exhibit an exercise intolerant phenotype. In vivo measurements of compound muscle action potentials showed a decrement in the evoked response in the MCT4-/- mice. This was accompanied by a significant structural degeneration of the neuromuscular junctions (NMJs). We propose that disruption of the lactate shuttle impacts motor function and destabilizes the motor unit.
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Affiliation(s)
- Sara Bisetto
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, Glenside, PA 19038, USA
| | - Romana A Nowak
- Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, USA
| | - Angelo C Lepore
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Tejvir S Khurana
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emanuele Loro
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Nancy J Philp
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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Robergs RA. Invited review: Quantifying proton exchange from chemical reactions - Implications for the biochemistry of metabolic acidosis. Comp Biochem Physiol A Mol Integr Physiol 2019; 235:29-45. [PMID: 31071454 DOI: 10.1016/j.cbpa.2019.04.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 01/30/2023]
Abstract
Given that the chemistry of lactate production disproves the existence of a lactic acidosis, there is a need to further reveal and explain the importance of the organic and computational chemistry of pH dependent competitive cation fractional (~) proton (H+) exchange (~H+e). An additional importance of this knowledge is that it could potentially contradict the assumption of the Stewart approach to the physico-chemical theory of acid-base balance. For example, Stewart proposed that chemical reaction and pH dependent H+ dissociation and association do not directly influence the pH of cellular and systemic body fluids. Yet at the time of Stewart's work, there were no data that quantified the H+ exchange during chemical reactions, or from pH dependent metabolite H+ association or dissociation. Consequently, the purpose of this review and commentary was three-fold; 1) to provide explanation of pH dependent competitive cation ~H+e exchange; 2) develop a model of and calculate new data of substrate flux in skeletal muscle during intense exercise; and 3) then combine substrate flux data with the now known ~H+e from chemical reactions of non-mitochondrial energy catabolism to quantify chemical reaction and metabolic pathway ~H+e. The results of purpose 3 were that ~H+ release for the totality of cytosolic energy catabolism = -187.2 mmol·L-1, where total glycolytic ~H+te = -85.0 mmol·L-1. ATP hydrolysis had a ~H+te = -43.1 mmol·L-1. Lactate production provided the largest metabolic ~H+ buffering with a ~H+te = 44.5 mmol·L-1. The total ~H+ release to La ratio = 4.25. The review content and research results of this manuscript should direct science towards new approaches to understanding the cause and source of H+e during metabolic acidosis and alkalosis.
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Affiliation(s)
- Robert A Robergs
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia.
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