1
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Flensted-Jensen M, Kleis-Olsen AS, Hassø RK, Lindtofte S, Corral Pérez J, Ortega-Gómez S, Larsen S. Combined changes in temperature and pH mimicking exercise result in decreased efficiency in muscle mitochondria. J Appl Physiol (1985) 2024; 136:79-88. [PMID: 37969081 DOI: 10.1152/japplphysiol.00293.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 11/07/2023] [Accepted: 11/10/2023] [Indexed: 11/17/2023] Open
Abstract
It is well known that exercise efficiency declines at intensities above the lactate threshold, yet the underlying mechanisms are poorly understood. Some have suggested it is due to a decline in mitochondrial efficiency, but this is difficult to examine in vivo. Therefore, the aim of the current study was to examine how changes in temperature and pH, mimicking those that occur during exercise, affect mitochondrial efficiency in skeletal muscle mitochondria. This study was performed on quadriceps muscle of 20 wild-type mice. Muscle tissue was dissected and either permeabilized (n = 10) or homogenized for isolation of mitochondria (n = 10), and oxidative phosphorylation capacity and P/O ratio were assessed using high-resolution respirometry. Samples from each muscle were analyzed in both normal physiological conditions (37°C, pH 7.4), decreased pH (6.8), increased temperature (40°C), and a combination of both. The combination of increased temperature and decreased pH resulted in a significantly lower P/O ratio, mirrored by an increase in leak respiration and a decrease in respiratory control ratio (RCR), in isolated mitochondria. In permeabilized fibers, RCR and leak were relatively unaffected, though a main effect of temperature was observed. Oxidative phosphorylation capacity was unaffected by changes in pH and temperature in both isolated mitochondria and permeabilized fibers. These results indicate that exercise-like changes in temperature and pH lead to impaired mitochondrial efficiency. These findings offer some degree of support to the concept of decreased mitochondrial efficiency during exercise, and may have implications for the assessment of mitochondrial function related to exercise.NEW & NOTEWORTHY To the best of our knowledge, this is the first study to examine the effects of combined changes in temperature and pH, mimicking intramuscular alterations during exercise. Our findings suggest that mitochondrial efficiency is impaired during exercise of moderate to high intensity, which could be a possible mechanism contributing to the decline in exercise efficiency at intensities above the lactate threshold.
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Affiliation(s)
- Mathias Flensted-Jensen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ann-Sofie Kleis-Olsen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rasmus Kinimond Hassø
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren Lindtofte
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Juan Corral Pérez
- MOVE-IT Research Group, Department of Physical Education, Faculty of Education Sciences, University of Cádiz, Cádiz, Spain
- ExPhy Research Group, Department of Physical Education, Instituto de Investigación e Innovación Biomédica de Cádiz (INiBICA), Universidad de Cádiz, Cádiz, Spain
| | - Sonia Ortega-Gómez
- MOVE-IT Research Group, Department of Physical Education, Faculty of Education Sciences, University of Cádiz, Cádiz, Spain
- Biomedical Research and Innovation Institute of Cádiz (INiBICA) Research Unit, Puerta del Mar University Hospital, Cádiz, Spain
| | - Steen Larsen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
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2
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Sokolova IM. Ectotherm mitochondrial economy and responses to global warming. Acta Physiol (Oxf) 2023; 237:e13950. [PMID: 36790303 DOI: 10.1111/apha.13950] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/24/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023]
Abstract
Temperature is a key abiotic factor affecting ecology, biogeography, and evolution of species. Alterations of energy metabolism play an important role in adaptations and plastic responses to temperature shifts on different time scales. Mitochondrial metabolism affects cellular bioenergetics and redox balance making these organelles an important determinant of organismal performances such as growth, locomotion, or development. Here I analyze the impacts of environmental temperature on the mitochondrial functions (including oxidative phosphorylation, proton leak, production of reactive oxygen species(ROS), and ATP synthesis) of ectotherms and discuss the mechanisms underlying negative shifts in the mitochondrial energy economy caused by supraoptimal temperatures. Owing to the differences in the thermal sensitivity of different mitochondrial processes, elevated temperatures (beyond the species- and population-specific optimal range) cause reallocation of the electron flux and the protonmotive force (Δp) in a way that decreases ATP synthesis efficiency, elevates the relative cost of the mitochondrial maintenance, causes excessive production of ROS and raises energy cost for antioxidant defense. These shifts in the mitochondrial energy economy might have negative consequences for the organismal fitness traits such as the thermal tolerance or growth. Correlation between the thermal sensitivity indices of the mitochondria and the whole organism indicate that these traits experience similar selective pressures but further investigations are needed to establish whether there is a cause-effect relationship between the mitochondrial failure and loss of organismal performance during temperature change.
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Affiliation(s)
- Inna M Sokolova
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, Rostock, Germany
- Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
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3
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Codella R, Alves TC, Befroy DE, Choi CS, Luzi L, Rothman DL, Kibbey RG, Shulman GI. Overexpression of UCP3 decreases mitochondrial efficiency in mouse skeletal muscle in vivo. FEBS Lett 2023; 597:309-319. [PMID: 36114012 DOI: 10.1002/1873-3468.14494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/25/2022] [Accepted: 09/05/2022] [Indexed: 01/29/2023]
Abstract
Uncoupling protein-3 (UCP3) is a mitochondrial transmembrane protein highly expressed in the muscle that has been implicated in regulating the efficiency of mitochondrial oxidative phosphorylation. Increasing UCP3 expression in skeletal muscle enhances proton leak across the inner mitochondrial membrane and increases oxygen consumption in isolated mitochondria, but its precise function in vivo has yet to be fully elucidated. To examine whether muscle-specific overexpression of UCP3 modulates muscle mitochondrial oxidation in vivo, rates of ATP synthesis were assessed by 31 P magnetic resonance spectroscopy (MRS), and rates of mitochondrial oxidative metabolism were measured by assessing the rate of [2-13 C]acetate incorporation into muscle [4-13 C]-, [3-13 C]-glutamate, and [4-13 C]-glutamine by high-resolution 13 C/1 H MRS. Using this approach, we found that the overexpression of UCP3 in skeletal muscle was accompanied by increased muscle mitochondrial inefficiency in vivo as reflected by a 42% reduction in the ratio of ATP synthesis to mitochondrial oxidation.
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Affiliation(s)
- Roberto Codella
- Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT, USA.,Department of Biomedical Sciences for Health, Università degli Studi di Milano, Italy.,Department of Endocrinology, Nutrition and Metabolic Diseases, IRCCS MultiMedica, Milan, Italy
| | - Tiago C Alves
- Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
| | - Douglas E Befroy
- Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT, USA.,Department of Diagnostic Radiology, Yale School of Medicine, New Haven, CT, USA
| | - Cheol Soo Choi
- Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
| | - Livio Luzi
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Italy.,Department of Endocrinology, Nutrition and Metabolic Diseases, IRCCS MultiMedica, Milan, Italy
| | - Douglas L Rothman
- Department of Diagnostic Radiology, Yale School of Medicine, New Haven, CT, USA
| | - Richard G Kibbey
- Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
| | - Gerald I Shulman
- Departments of Internal Medicine and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
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4
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Saito ER, Warren CE, Hanegan CM, Larsen JG, du Randt JD, Cannon M, Saito JY, Campbell RJ, Kemberling CM, Miller GS, Edwards JG, Bikman BT. A Novel Ketone-Supplemented Diet Improves Recognition Memory and Hippocampal Mitochondrial Efficiency in Healthy Adult Mice. Metabolites 2022; 12:1019. [PMID: 36355101 PMCID: PMC9693360 DOI: 10.3390/metabo12111019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 09/13/2023] Open
Abstract
Mitochondrial dysfunction and cognitive impairment are common symptoms in many neurologic and psychiatric disorders, as well as nonpathological aging. Ketones have been suggested as therapeutic for their efficacy in epilepsy and other brain pathologies such as Alzheimer's disease and major depressive disorder. However, their effects on cognitive function in healthy individuals is less established. Here, we explored the mitochondrial and performative outcomes of a novel eight-week ketone-supplemented ketogenic (KETO) diet in healthy adult male and female mice. In a novel object recognition test, KETO mice spent more time with the novel, compared to familiar, object, indicating an improvement in recognition memory. High-resolution respirometry on permeabilized hippocampal tissue returned significant reductions in mitochondrial O2 consumption. No changes in ATP production were observed, yielding a significantly higher ATP:O2 ratio, a measure of mitochondrial efficiency. Together, these findings demonstrate the KETO diet improves hippocampal mitochondrial efficiency. They add to a growing body of evidence that suggests ketones and ketogenic diets are neuroprotective and metabolically and cognitively relevant, even in healthy adults. They also suggest that ketogenic lifestyle changes may be effective strategies for protecting against cognitive decline associated with aging and disease.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Benjamin T. Bikman
- Department of Cell Biology and Physiology, Brigham Young University, Provo, UT 84602, USA
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5
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Brzęk P, Roussel D, Konarzewski M. Mice selected for a high basal metabolic rate evolved larger guts but not more efficient mitochondria. Proc Biol Sci 2022; 289:20220719. [PMID: 35858057 PMCID: PMC9277295 DOI: 10.1098/rspb.2022.0719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Intra-specific variation in both the basal metabolic rate (BMR) and mitochondrial efficiency (the amount of ATP produced per unit of oxygen consumed) has profound evolutionary and ecological consequences. However, the functional mechanisms responsible for this variation are not fully understood. Mitochondrial efficiency is negatively correlated with BMR at the interspecific level but it is positively correlated with performance capacity at the intra-specific level. This discrepancy is surprising, as theories explaining the evolution of endothermy assume a positive correlation between BMR and performance capacity. Here, we quantified mitochondrial oxidative phosphorylation activity and efficiency in two lines of laboratory mice divergently selected for either high (H-BMR) or low (L-BMR) levels of BMR. H-BMR mice had larger livers and kidneys (organs that are important predictors of BMR). H-BMR mice also showed higher oxidative phosphorylation activity in liver mitochondria but this difference can be hypothesized to be a direct effect of selection only if the heritability of this trait is low. However, mitochondrial efficiency in all studied organs did not differ between the two lines. We conclude that the rapid evolution of BMR can reflect changes in organ size rather than mitochondrial properties, and does not need to be accompanied obligatorily by changes in mitochondrial efficiency.
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Affiliation(s)
- Paweł Brzęk
- Faculty of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland
| | - Damien Roussel
- Univ Lyon, Université Claude Bernard Lyon 1, UMR 5023 LEHNA, CNRS, ENTPE, Villeurbanne, France
| | - Marek Konarzewski
- Faculty of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland
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6
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Koch RE, Buchanan KL, Casagrande S, Crino O, Dowling DK, Hill GE, Hood WR, McKenzie M, Mariette MM, Noble DWA, Pavlova A, Seebacher F, Sunnucks P, Udino E, White CR, Salin K, Stier A. Integrating Mitochondrial Aerobic Metabolism into Ecology and Evolution. Trends Ecol Evol 2021; 36:321-332. [PMID: 33436278 DOI: 10.1016/j.tree.2020.12.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 12/17/2022]
Abstract
Biologists have long appreciated the critical role that energy turnover plays in understanding variation in performance and fitness among individuals. Whole-organism metabolic studies have provided key insights into fundamental ecological and evolutionary processes. However, constraints operating at subcellular levels, such as those operating within the mitochondria, can also play important roles in optimizing metabolism over different energetic demands and time scales. Herein, we explore how mitochondrial aerobic metabolism influences different aspects of organismal performance, such as through changing adenosine triphosphate (ATP) and reactive oxygen species (ROS) production. We consider how such insights have advanced our understanding of the mechanisms underpinning key ecological and evolutionary processes, from variation in life-history traits to adaptation to changing thermal conditions, and we highlight key areas for future research.
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Affiliation(s)
- Rebecca E Koch
- Monash University, School of Biological Sciences, Clayton, VIC, 3800, Australia.
| | - Katherine L Buchanan
- Deakin University, School of Life and Environmental Sciences, Waurn Ponds, VIC, 3228, Australia
| | - Stefania Casagrande
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, Seewiesen, Eberhard-Gwinner-Str. Haus 5, 82319, Seewiesen, Germany
| | - Ondi Crino
- Deakin University, School of Life and Environmental Sciences, Waurn Ponds, VIC, 3228, Australia
| | - Damian K Dowling
- Monash University, School of Biological Sciences, Clayton, VIC, 3800, Australia
| | - Geoffrey E Hill
- Auburn University, Department of Biological Sciences, Auburn, AL, 36849, USA
| | - Wendy R Hood
- Auburn University, Department of Biological Sciences, Auburn, AL, 36849, USA
| | - Matthew McKenzie
- Deakin University, School of Life and Environmental Sciences, Waurn Ponds, VIC, 3228, Australia
| | - Mylene M Mariette
- Deakin University, School of Life and Environmental Sciences, Waurn Ponds, VIC, 3228, Australia
| | - Daniel W A Noble
- The Australian National University, Division of Ecology and Evolution, Research School of Biology, Canberra, ACT, 2600, Australia
| | - Alexandra Pavlova
- Monash University, School of Biological Sciences, Clayton, VIC, 3800, Australia
| | - Frank Seebacher
- University of Sydney, School of Life and Environmental Sciences, Sydney, NSW, 2006, Australia
| | - Paul Sunnucks
- Monash University, School of Biological Sciences, Clayton, VIC, 3800, Australia
| | - Eve Udino
- Deakin University, School of Life and Environmental Sciences, Waurn Ponds, VIC, 3228, Australia
| | - Craig R White
- Monash University, School of Biological Sciences, Clayton, VIC, 3800, Australia
| | - Karine Salin
- Université de Brest, Ifremer, CNRS, IRD, Laboratory of Environmental Marine Sciences, Plouzané, 29280, France
| | - Antoine Stier
- University of Turku, Department of Biology, Turku, Finland; University of Glasgow, Institute of Biodiversity, Animal Health and Comparative Medicine, Glasgow, UK
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7
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Murashov AK, Pak ES, Lin C, Boykov IN, Buddo KA, Mar J, Bhat KM, Neufer PD. Preference and detrimental effects of high fat, sugar, and salt diet in wild-caught Drosophila simulans are reversed by flight exercise. FASEB Bioadv 2021; 3:49-64. [PMID: 33490883 PMCID: PMC7805546 DOI: 10.1096/fba.2020-00079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/14/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022] Open
Abstract
High saturated fat, sugar, and salt contents are a staple of a Western diet (WD), contributing to obesity, metabolic syndrome, and a plethora of other health risks. However, the combinatorial effects of these ingredients have not been fully evaluated. Here, using the wild-caught Drosophila simulans, we show that a diet enriched with saturated fat, sugar, and salt is more detrimental than each ingredient separately, resulting in a significantly decreased lifespan, locomotor activity, sleep, reproductive function, and mitochondrial function. These detrimental effects were more pronounced in female than in male flies. Adding regular flight exercise to flies on the WD markedly negated the adverse effects of a WD. At the molecular level, the WD significantly increased levels of triglycerides and caused mitochondrial dysfunction, while exercise counterbalanced these effects. Interestingly, fruit flies developed a preference for the WD after pre-exposure, which was averted by flight exercise. The results demonstrate that regular aerobic exercise can mitigate adverse dietary effects on fly mitochondrial function, physiology, and feeding behavior. Our data establish Drosophila simulans as a novel model of diet-exercise interaction that bears a strong similarity to the pathophysiology of obesity and eating disorders in humans.
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Affiliation(s)
- Alexander K. Murashov
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
| | - Elena S. Pak
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
| | - Chien‐Te Lin
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
| | - Ilya N. Boykov
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
| | - Katherine A. Buddo
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
| | - Jordan Mar
- Department of Molecular MedicineUniversity of South FloridaTampaFLUSA
| | - Krishna M. Bhat
- Department of Molecular MedicineUniversity of South FloridaTampaFLUSA
| | - Peter Darrell Neufer
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
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8
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Roussel D, Voituron Y. Mitochondrial Costs of Being Hot: Effects of Acute Thermal Change on Liver Bioenergetics in Toads ( Bufo bufo). Front Physiol 2020; 11:153. [PMID: 32218742 PMCID: PMC7078649 DOI: 10.3389/fphys.2020.00153] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/12/2020] [Indexed: 01/21/2023] Open
Abstract
Global climatic warming is predicted to drive extreme thermal events, especially in temperate terrestrial environments. Hence, describing how physiological parameters are affected by acute temperature changes would allow us to understand the energy management of organisms facing such non-predictable and constraining events. As mitochondria play a key role in the conversion of energy from food into ATP but also produce harmful reactive oxygen species, the understanding of its functioning is crucial to determine the proximal causes of potential decline in an animal's performance. Here we studied the effects of acute temperature changes (between 20 and 30°C) on mitochondrial respiration, ATP synthesis rate, oxidative phosphorylation efficiency (ATP/O), and H2O2 generation in isolated liver mitochondria of a terrestrial ectotherm, the common toad (Bufo bufo). Using succinate as the respiratory substrate, we found that the mitochondrial rates of oxygen consumption, ATP synthesis, and H2O2 generation increased as the temperature increased, being 65, 52, and 66% higher at 30°C than at 20°C, respectively. We also found that the mitochondrial coupling efficiency (ATP/O) decreased, while the oxidative cost of ATP production (H2O2/ATP ratio) increased. The present results further indicate that between 40 and 60% of temperature effects on mitochondrial ATP production and H2O2 generation was at minima driven by an action on the oxidative capacity of the mitochondria. These results suggest that B. bufo may need to allocate extra energy to maintain ATP production and protect cells from oxidative stress, reducing the energy allocable performances.
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Affiliation(s)
- Damien Roussel
- CNRS, UMR 5023, Laboratoire d’Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Claude Bernard Lyon 1, Lyon, France
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9
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Fiorenza M, Lemminger AK, Marker M, Eibye K, Iaia FM, Bangsbo J, Hostrup M. High-intensity exercise training enhances mitochondrial oxidative phosphorylation efficiency in a temperature-dependent manner in human skeletal muscle: implications for exercise performance. FASEB J 2019; 33:8976-8989. [PMID: 31136218 DOI: 10.1096/fj.201900106rrr] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The purpose of the present study was to investigate whether exercise training-induced adaptations in human skeletal muscle mitochondrial bioenergetics are magnified under thermal conditions resembling sustained intense contractile activity and whether training-induced changes in mitochondrial oxidative phosphorylation (OXPHOS) efficiency influence exercise efficiency. Twenty healthy men performed 6 wk of high-intensity exercise training [i.e., speed endurance training (SET; n = 10)], or maintained their usual lifestyle (n = 10). Before and after the intervention, mitochondrial respiratory function was determined ex vivo in permeabilized muscle fibers under experimentally-induced normothermia (35°C) and hyperthermia (40°C) mimicking in vivo muscle temperature at rest and during intense exercise, respectively. In addition, activity and content of muscle mitochondrial enzymes and proteins were quantified. Exercising muscle efficiency was determined in vivo by measurements of leg hemodynamics and blood parameters during one-legged knee-extensor exercise. SET enhanced maximal OXPHOS capacity and OXPHOS efficiency at 40°C, but not at 35°C, and attenuated hyperthermia-induced decline in OXPHOS efficiency. Furthermore, SET increased expression of markers of mitochondrial content and up-regulated content of MFN2, DRP1, and ANT1. Also, SET improved exercise efficiency and capacity. These findings indicate that muscle mitochondrial bioenergetics adapts to high-intensity exercise training in a temperature-dependent manner and that enhancements in mitochondrial OXPHOS efficiency may contribute to improving exercise performance.-Fiorenza, M., Lemminger, A. K., Marker, M., Eibye, K., Iaia, F. M., Bangsbo, J., Hostrup, M. High-intensity exercise training enhances mitochondrial oxidative phosphorylation efficiency in a temperature-dependent manner in human skeletal muscle: implications for exercise performance.
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Affiliation(s)
- Matteo Fiorenza
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark.,Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Anders K Lemminger
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Mathias Marker
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Kasper Eibye
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - F Marcello Iaia
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
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10
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Abstract
Mitochondrial metabolic plasticity is a key adaptive mechanism in response to changes in cellular metabolic demand. Changes in mitochondrial metabolic efficiency have been linked to pathophysiological conditions, including cancer, neurodegeneration, and obesity. The ubiquitously expressed DJ-1 (Parkinsonism-associated deglycase) is known as a Parkinson's disease gene and an oncogene. The pleiotropic functions of DJ-1 include reactive oxygen species scavenging, RNA binding, chaperone activity, endocytosis, and modulation of major signaling pathways involved in cell survival and metabolism. Nevertheless, how these functions are linked to the role of DJ-1 in mitochondrial plasticity is not fully understood. In this study, we describe an interaction between DJ-1 and 14-3-3β that regulates the localization of DJ-1, in a hypoxia-dependent manner, either to the cytosol or to mitochondria. This interaction acts as a modulator of mitochondrial metabolic efficiency and a switch between glycolysis and oxidative phosphorylation. Modulation of this novel molecular mechanism of mitochondrial metabolic efficiency is potentially involved in the neuroprotective function of DJ-1 as well as its role in proliferation of cancer cells.-Weinert, M., Millet, A., Jonas, E. A., Alavian, K. N. The mitochondrial metabolic function of DJ-1 is modulated by 14-3-3β.
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Affiliation(s)
- Maria Weinert
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom
| | - Aurelie Millet
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom
| | - Elizabeth A Jonas
- Division of Endocrinology, Department of Internal Medicine, Yale University, New Haven, Connecticut, USA
| | - Kambiz N Alavian
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom.,Division of Endocrinology, Department of Internal Medicine, Yale University, New Haven, Connecticut, USA
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11
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Akhnokh MK, Yang FH, Samokhvalov V, Jamieson KL, Cho WJ, Wagg C, Takawale A, Wang X, Lopaschuk GD, Hammock BD, Kassiri Z, Seubert JM. Inhibition of Soluble Epoxide Hydrolase Limits Mitochondrial Damage and Preserves Function Following Ischemic Injury. Front Pharmacol 2016; 7:133. [PMID: 27375480 PMCID: PMC4896112 DOI: 10.3389/fphar.2016.00133] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 05/09/2016] [Indexed: 12/26/2022] Open
Abstract
Aims: Myocardial ischemia can result in marked mitochondrial damage leading to cardiac dysfunction, as such identifying novel mechanisms to limit mitochondrial injury is important. This study investigated the hypothesis that inhibiting soluble epoxide hydrolase (sEH), responsible for converting epoxyeicosatrienoic acids to dihydroxyeicosatrienoic acids protects mitochondrial from injury caused by myocardial infarction. Methods: sEH null and WT littermate mice were subjected to surgical occlusion of the left anterior descending (LAD) artery or sham operation. A parallel group of WT mice received an sEH inhibitor, trans-4-[4-(3-adamantan-1-y1-ureido)-cyclohexyloxy]-benzoic acid (tAUCB; 10 mg/L) or vehicle in the drinking water 4 days prior and 7 days post-MI. Cardiac function was assessed by echocardiography prior- and 7-days post-surgery. Heart tissues were dissected into infarct, peri-, and non-infarct regions to assess ultrastructure by electron microscopy. Complexes I, II, IV, citrate synthase, PI3K activities, and mitochondrial respiration were assessed in non-infarct regions. Isolated working hearts were used to measure the rates of glucose and palmitate oxidation. Results: Echocardiography revealed that tAUCB treatment or sEH deficiency significantly improved systolic and diastolic function post-MI compared to controls. Reduced infarct expansion and less adverse cardiac remodeling were observed in tAUCB-treated and sEH null groups. EM data demonstrated mitochondrial ultrastructure damage occurred in infarct and peri-infarct regions but not in non-infarct regions. Inhibition of sEH resulted in significant improvements in mitochondrial respiration, ATP content, mitochondrial enzymatic activities and restored insulin sensitivity and PI3K activity. Conclusion: Inhibition or genetic deletion of sEH protects against long-term ischemia by preserving cardiac function and maintaining mitochondrial efficiency.
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Affiliation(s)
- Maria K Akhnokh
- Faculty of Pharmacy and Pharmaceutical Sciences, 2-020M Katz Group Centre for Pharmacy and Health Research, University of Alberta Edmonton, AB, Canada
| | - Feng Hua Yang
- Guangdong Laboratory Animal Monitoring Institute Guangdong, China
| | - Victor Samokhvalov
- Faculty of Pharmacy and Pharmaceutical Sciences, 2-020M Katz Group Centre for Pharmacy and Health Research, University of Alberta Edmonton, AB, Canada
| | - Kristi L Jamieson
- Faculty of Pharmacy and Pharmaceutical Sciences, 2-020M Katz Group Centre for Pharmacy and Health Research, University of Alberta Edmonton, AB, Canada
| | - Woo Jung Cho
- Imaging Core Facility, Faculty of Medicine and Dentistry, University of Alberta Edmonton, AB, Canada
| | - Cory Wagg
- Mazankowski Alberta Heart Institute, University of AlbertaEdmonton, AB, Canada; Department of Pharmacology, Faculty of Medicine and Dentistry, University of AlbertaEdmonton, AB, Canada
| | - Abhijit Takawale
- Mazankowski Alberta Heart Institute, University of AlbertaEdmonton, AB, Canada; Department of Physiology, Faculty of Medicine and Dentistry, University of AlbertaEdmonton, AB, Canada
| | - Xiuhua Wang
- Mazankowski Alberta Heart Institute, University of AlbertaEdmonton, AB, Canada; Department of Physiology, Faculty of Medicine and Dentistry, University of AlbertaEdmonton, AB, Canada
| | - Gary D Lopaschuk
- Mazankowski Alberta Heart Institute, University of AlbertaEdmonton, AB, Canada; Department of Pharmacology, Faculty of Medicine and Dentistry, University of AlbertaEdmonton, AB, Canada; Department of Pediatrics, Faculty of Medicine and Dentistry, University of AlbertaEdmonton, AB, Canada
| | - Bruce D Hammock
- Department of Entomology and Nematology Comprehensive Cancer Center, University of California, Davis Davis, CA, USA
| | - Zamaneh Kassiri
- Mazankowski Alberta Heart Institute, University of AlbertaEdmonton, AB, Canada; Department of Physiology, Faculty of Medicine and Dentistry, University of AlbertaEdmonton, AB, Canada
| | - John M Seubert
- Faculty of Pharmacy and Pharmaceutical Sciences, 2-020M Katz Group Centre for Pharmacy and Health Research, University of AlbertaEdmonton, AB, Canada; Mazankowski Alberta Heart Institute, University of AlbertaEdmonton, AB, Canada; Department of Pharmacology, Faculty of Medicine and Dentistry, University of AlbertaEdmonton, AB, Canada
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12
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Cerqueira FM, Chausse B, Baranovski BM, Liesa M, Lewis EC, Shirihai OS, Kowaltowski AJ. Diluted serum from calorie-restricted animals promotes mitochondrial β-cell adaptations and protect against glucolipotoxicity. FEBS J 2016; 283:822-33. [PMID: 26732506 DOI: 10.1111/febs.13632] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 11/04/2015] [Accepted: 12/16/2015] [Indexed: 12/20/2022]
Abstract
β-cells quickly adjust insulin secretion to oscillations in nutrients carried by the blood, acting as fuel sensors. However, most studies of β-cell responses to nutrients do not discriminate between fuel levels and signaling components present in the circulation. Here we studied the effect of serum from calorie-restricted rats versus serum from rats fed ad libitum, diluted tenfold in the medium, which did not contribute significantly to the pool of nutrients, on β-cell mitochondrial function and dynamics under regular and high-nutrient culture conditions. Insulin secreting beta-cell derived line (INS1) cells incubated with serum from calorie-restricted rats (CR serum) showed higher levels of peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) and active nitric oxide synthase. The expression of mitofusin-2 (Mfn-2) and optic atrophy 1 (OPA-1), proteins involved in mitochondrial fusion, was increased, while the levels of the mitochondrial fission mediator dynamin related protein 1 (DRP-1) were reduced. Consistent with changes in mitochondrial dynamics protein levels, CR serum treatment increased mitochondrial fusion rates, as well as their length and connectivity. These changes in mitochondrial morphology were associated with prolonged glucose-stimulated insulin secretion and mitochondrial respiration. When combining CR serum and high levels of glucose and palmitate (20 and 0.4 mm, respectively), an in vitro model of type II diabetes, we observed that signaling promoted by CR serum was enough to overcome glucolipotoxicity, as indicated by CR-mediated prevention of mitochondrial fusion arrest and reduced respiratory function in INS1 cells under glucolipotoxicity. Overall, our results provide evidence that non-nutrient factors in serum have a major impact on β-cell mitochondrial adaptations to changes in metabolism.
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Affiliation(s)
- Fernanda M Cerqueira
- Department of Medicine, Boston University School of Medicine, MA, USA.,Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel.,Departamento de Bioquímica, Universidade de São Paulo, Brazil
| | - Bruno Chausse
- Departamento de Bioquímica, Universidade de São Paulo, Brazil
| | - Boris M Baranovski
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel
| | - Marc Liesa
- Department of Medicine, Boston University School of Medicine, MA, USA.,UCLA Section of Endocrinology, Department of Medicine, David Geffen School of Medicine, UCLA, CA, USA
| | - Eli C Lewis
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel
| | - Orian S Shirihai
- Department of Medicine, Boston University School of Medicine, MA, USA.,Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel.,UCLA Section of Endocrinology, Department of Medicine, David Geffen School of Medicine, UCLA, CA, USA
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13
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Vaughan RA, Gannon NP, Carriker CR. Nitrate-containing beetroot enhances myocyte metabolism and mitochondrial content. J Tradit Complement Med 2015; 6:17-22. [PMID: 26870674 PMCID: PMC4737966 DOI: 10.1016/j.jtcme.2014.11.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 10/26/2014] [Accepted: 11/11/2014] [Indexed: 01/08/2023] Open
Abstract
Beetroot (甜菜 tián cài) juice consumption is of current interest for improving aerobic performance by acting as a vasodilator and possibly through alterations in skeletal muscle metabolism and physiology. This work explored the effects of a commercially available beetroot supplement on metabolism, gene expression, and mitochondrial content in cultured myocytes. C2C12 myocytes were treated with various concentrations of the beetroot supplement for various durations. Glycolytic metabolism and oxidative metabolism were quantified via measurement of extracellular acidification and oxygen consumption, respectively. Metabolic gene expression was measured using quantitative reverse transcription–polymerase chain reaction, and mitochondrial content was assessed with flow cytometry and confocal microscopy. Cells treated with beetroot exhibited significantly increased oxidative metabolism, concurrently with elevated metabolic gene expression including peroxisome proliferator-activated receptor gamma coactivator-1 alpha, nuclear respiratory factor 1, mitochondrial transcription factor A, and glucose transporter 4, leading to increased mitochondrial biogenesis. Our data show that treatment with a beetroot supplement increases basal oxidative metabolism. Our observations are also among the first to demonstrate that beetroot extract is an inducer of metabolic gene expression and mitochondrial biogenesis. These observations support the need for further investigation into the therapeutic and pharmacological effects of nitrate-containing supplements for health and athletic benefits.
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Affiliation(s)
- Roger A Vaughan
- Department of Nutritional Sciences, Texas Tech University, PO Box 41270, Lubbock 79409, TX, USA; Department of Health, Exercise and Sports Science, University of New Mexico, Albuquerque 87131, NM, USA; Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, School of Medicine, Albuquerque 87131, NM, USA; Department of Individual, Family, and Community Education: Nutrition, University of New Mexico, Albuquerque 87131, NM, USA
| | - Nicholas P Gannon
- Department of Health, Exercise and Sports Science, University of New Mexico, Albuquerque 87131, NM, USA
| | - Colin R Carriker
- Department of Health, Exercise and Sports Science, University of New Mexico, Albuquerque 87131, NM, USA; Department of Kinesiology, Recreation, and Sport, Indiana State University, Terre Haute 47809, IN, USA
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14
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Pham T, Loiselle D, Power A, Hickey AJR. Mitochondrial inefficiencies and anoxic ATP hydrolysis capacities in diabetic rat heart. Am J Physiol Cell Physiol 2014; 307:C499-507. [PMID: 24920675 DOI: 10.1152/ajpcell.00006.2014] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
As ~80% of diabetic patients die from heart failure, an understanding of diabetic cardiomyopathy is crucial. Mitochondria occupy 35-40% of the mammalian cardiomyocyte volume and supply 95% of the heart's ATP, and diabetic heart mitochondria show impaired structure, arrangement, and function. We predict that bioenergetic inefficiencies are present in diabetic heart mitochondria; therefore, we explored mitochondrial proton and electron handling by linking oxygen flux to steady-state ATP synthesis, reactive oxygen species (ROS) production, and mitochondrial membrane potential (ΔΨ) within rat heart tissues. Sprague-Dawley rats were injected with streptozotocin (STZ, 55 mg/kg) to induce type 1 diabetes or an equivalent volume of saline (control, n = 12) and fed standard rat chow for 8 wk. By coupling high-resolution respirometers with purpose-built fluorometers, we followed Magnesium Green (ATP synthesis), Amplex UltraRed (ROS production), and safranin-O (ΔΨ). Relative to control rats, the mass-specific respiration of STZ-diabetic hearts was depressed in oxidative phosphorylation (OXPHOS) states. Steady-state ATP synthesis capacity was almost one-third lower in STZ-diabetic heart, which, relative to oxygen flux, equates to an estimated 12% depression in OXPHOS efficiency. However, with anoxic transition, STZ-diabetic and control heart tissues showed similar ATP hydrolysis capacities through reversal of the F1F0-ATP synthase. STZ-diabetic cardiac mitochondria also produced more net ROS relative to oxygen flux (ROS/O) in OXPHOS. While ΔΨ did not differ between groups, the time to develop ΔΨ with the onset of OXPHOS was protracted in STZ-diabetic mitochondria. ROS/O is higher in lifelike OXPHOS states, and potential delays in the time to develop ΔΨ may delay ATP synthesis with interbeat fluctuations in ADP concentrations. Whereas diabetic cardiac mitochondria produce less ATP in normoxia, they consume as much ATP in anoxic infarct-like states.
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Affiliation(s)
- Toan Pham
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Denis Loiselle
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; and Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Amelia Power
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Anthony J R Hickey
- School of Biological Sciences, University of Auckland, Auckland, New Zealand;
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15
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Trexler ET, Smith-Ryan AE, Melvin MN, Roelofs EJ, Wingfield HL. Effects of pomegranate extract on blood flow and running time to exhaustion. Appl Physiol Nutr Metab 2014; 39:1038-42. [PMID: 25051173 DOI: 10.1139/apnm-2014-0137] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Recent research has shown that dietary nitrate has favorable effects on blood flow and exercise performance. The purpose of this randomized, double-blind, placebo-controlled crossover study was to investigate the acute effects of pomegranate extract on blood flow, vessel diameter, and exercise performance in active individuals. Nineteen men and women (mean ± SD: age, 22.2 ± 2.2 years; height, 174.8 ± 10.7 cm; body mass, 71.9 ± 13.5 kg) were randomly assigned to a placebo (PL) or pomegranate extract (PE) group. Participants performed a maximal oxygen consumption treadmill test to determine peak velocity (PV). Participants returned after 24-48 h and ingested either PL or PE. Brachial artery blood flow was assessed using ultrasound at baseline and 30 min post-ingestion (30minPI). Three treadmill runs to exhaustion were performed at 90%, 100%, and 110% PV. Blood flow was assessed immediately after each exercise bout and 30 min postexercise (30minPEx). After a 7-10 day washout, participants repeated the same procedures, ingesting the opposite supplement. Separate repeated measures ANOVAs were performed for blood flow, vessel diameter, and time to exhaustion (TTE). Blood flow was significantly augmented (p = 0.033) 30minPI with PE in comparison with PL. Vessel diameter was significantly larger (p = 0.036) 30minPEx with PE. Ingestion of PE was found to significantly augment TTE at 90% (p = 0.009) and 100% PV (p = 0.027). Acute ingestion of PE 30 min before exercise may enhance vessel diameter and blood flow and delay fatigue during exercise. Results of the current study indicate that PE is ergogenic for intermittent running, eliciting beneficial effects on blood flow.
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Affiliation(s)
- Eric T Trexler
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Mollica MP, Trinchese G, Cavaliere G, De Filippo C, Cocca E, Gaita M, Della-Gatta A, Marano A, Mazzarella G, Bergamo P. c9,t11-Conjugated linoleic acid ameliorates steatosis by modulating mitochondrial uncoupling and Nrf2 pathway. J Lipid Res 2014; 55:837-49. [PMID: 24634500 DOI: 10.1194/jlr.m044032] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Oxidative stress, hepatic steatosis, and mitochondrial dysfunction are key pathophysiological features of nonalcoholic fatty liver disease. A conjugated linoleic acid (CLA) mixture of cis9,trans11 (9,11-CLA) and trans10,cis12 (10,12-CLA) isomers enhanced the antioxidant/detoxifying mechanism via the activation of nuclear factor E2-related factor-2 (Nrf2) and improved mitochondrial function, but less is known about the actions of specific isomers. The differential ability of individual CLA isomers to modulate these pathways was explored in Wistar rats fed for 4 weeks with a lard-based high-fat diet (L) or with control diet (CD), and, within each dietary treatment, two subgroups were daily administered with 9,11-CLA or 10,12-CLA (30 mg/day). The 9,11-CLA, but not 10,12-CLA, supplementation to CD rats improves the GSH/GSSG ratio in the liver, mitochondrial functions, and Nrf2 activity. Histological examination reveals a reduction of steatosis in L-fed rats supplemented with both CLA isomers, but 9,11-CLA downregulated plasma concentrations of proinflammatory markers, mitochondrial dysfunction, and oxidative stress markers in liver more efficiently than in 10,12-CLA treatment. The present study demonstrates the higher protective effect of 9,11-CLA against diet-induced pro-oxidant and proinflammatory signs and suggests that these effects are determined, at least in part, by its ability to activate the Nrf2 pathway and to improve the mitochondrial functioning and biogenesis.
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Affiliation(s)
- Maria Pina Mollica
- Dipartimento delle Scienze Biologiche, Università degli Studi di Napoli "Federico II," Napoli, Italy
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Bronikowski AM. The evolution of aging phenotypes in snakes: a review and synthesis with new data. Age (Dordr) 2008; 30:169-76. [PMID: 19424866 PMCID: PMC2527626 DOI: 10.1007/s11357-008-9060-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 04/22/2008] [Indexed: 05/27/2023]
Abstract
Reptiles are underutilized vertebrate models in the study of the evolution and persistence of senescence. Their unique physiology, indeterminate growth, and increasing fecundity across the adult female lifespan motivate the study of how physiology at the mechanistic level, life history at the organismal level, and natural selection at the evolutionary timescale define lifespan in this diverse taxonomic group. Reviewed here are, first, comparative results of cellular metabolic studies conducted across a range of colubrid snake species with variable lifespan. New results on the efficiency of DNA repair in these species are synthesized with the cellular studies. Second, detailed studies of the ecology, life history, and cellular physiology are reviewed for one colubrid species with either short or long lifespan (Thamnophis elegans). New results on the rate of telomere shortening with age in this species are synthesized with previous research. The comparative and intraspecific studies both yield results that species with longer lifespans have underlying cellular physiologies support the free-radical/repair mechanistic hypothesis for aging. As well, both underscore the importance of mortality environment for the evolution of aging rate.
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Affiliation(s)
- Anne M Bronikowski
- Ecology, Evolution and Organismal Biology, Iowa State University, 253 Bessey Hall, Ames, IA 50011, USA.
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