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Kugler BA, Thyfault JP, McCoin CS. Sexually dimorphic hepatic mitochondrial adaptations to exercise: a mini-review. J Appl Physiol (1985) 2023; 134:685-691. [PMID: 36701482 PMCID: PMC10027083 DOI: 10.1152/japplphysiol.00711.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023] Open
Abstract
Exercise is a physiological stress that disrupts tissue and cellular homeostasis while enhancing systemic metabolic energy demand mainly through the increased workload of skeletal muscle. Although the extensive focus has been on skeletal muscle adaptations to exercise, the liver senses these disruptions in metabolic energy homeostasis and responds to provide the required substrates to sustain increased demand. Hepatic metabolic flexibility is an energetically costly process that requires continuous mitochondrial production of the cellular currency ATP. To do so, the liver must maintain a healthy functioning mitochondrial pool, attained through well-regulated and dynamic processes. Intriguingly, some of these responses are sex-dependent. This mini-review examines the hepatic mitochondrial adaptations to exercise with a focus on sexual dimorphism.
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Affiliation(s)
- Benjamin A Kugler
- Department of Cell Biology and Physiology, The University of Kansas Medical Center, Kansas City, Kansas, United States
- KU Diabetes Institute, The University of Kansas Medical Center, Kansas City, Kansas, United States
- Kansas Center for Metabolism and Obesity Research, The University of Kansas Medical Center, Kansas City, Kansas, United States
| | - John P Thyfault
- Department of Cell Biology and Physiology, The University of Kansas Medical Center, Kansas City, Kansas, United States
- KU Diabetes Institute, The University of Kansas Medical Center, Kansas City, Kansas, United States
- Kansas Center for Metabolism and Obesity Research, The University of Kansas Medical Center, Kansas City, Kansas, United States
- Center for Children's Healthy Lifestyles and Nutrition, Kansas City, Missouri, United States
- Division of Endocrinology and Metabolism, Department of Internal Medicine, The University of Kansas Medical Center, Kansas City, Kansas, United States
- Kansas City Veterans Affairs Medical Center, Kansas City, Missouri, United States
| | - Colin S McCoin
- Department of Cell Biology and Physiology, The University of Kansas Medical Center, Kansas City, Kansas, United States
- KU Diabetes Institute, The University of Kansas Medical Center, Kansas City, Kansas, United States
- Kansas Center for Metabolism and Obesity Research, The University of Kansas Medical Center, Kansas City, Kansas, United States
- Center for Children's Healthy Lifestyles and Nutrition, Kansas City, Missouri, United States
- Kansas City Veterans Affairs Medical Center, Kansas City, Missouri, United States
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Fredrickson G, Barrow F, Dietsche K, Parthiban P, Khan S, Robert S, Demirchian M, Rhoades H, Wang H, Adeyi O, Revelo XS. Exercise of high intensity ameliorates hepatic inflammation and the progression of NASH. Mol Metab 2021; 53:101270. [PMID: 34118476 PMCID: PMC8255932 DOI: 10.1016/j.molmet.2021.101270] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/25/2021] [Accepted: 06/01/2021] [Indexed: 02/06/2023] Open
Abstract
Objective Non-alcoholic fatty liver disease (NAFLD) covers a wide spectrum of liver pathology ranging from simple fatty liver to non-alcoholic steatohepatitis (NASH). Notably, immune cell-driven inflammation is a key mechanism in the transition from fatty liver to the more serious NASH. Although exercise training is effective in ameliorating obesity-related diseases, the underlying mechanisms of the beneficial effects of exercise remain unclear. It is unknown whether there is an optimal modality and intensity of exercise to treat NAFLD. The objective of this study was to determine whether high-intensity interval training (HIIT) or moderate-intensity continuous training (MIT) is more effective at ameliorating the progression of NASH. Methods Wild-type mice were fed a high-fat, high-carbohydrate (HFHC) diet for 6 weeks and left sedentary (SED) or assigned to either an MIT or HIIT regimen using treadmill running for an additional 16 weeks. MIT and HIIT groups were pair-fed to ensure that energy intake was similar between the exercise cohorts. To determine changes in whole-body metabolism, we performed insulin and glucose tolerance tests, indirect calorimetry, and magnetic resonance imaging. NASH progression was determined by triglyceride accumulation, expression of inflammatory genes, and histological assessment of fibrosis. Immune cell populations in the liver were characterized by cytometry by time-of-flight mass spectrometry, and progenitor populations within the bone marrow were assessed by flow cytometry. Finally, we analyzed the transcriptional profile of the liver by bulk RNA sequencing. Results Compared with SED mice, both HIIT and MIT suppressed weight gain, improved whole-body metabolic parameters, and ameliorated the progression of NASH by reducing hepatic triglyceride levels, inflammation, and fibrosis. However, HIIT was superior to MIT at reducing adiposity, improving whole-body glucose tolerance, and ameliorating liver steatosis, inflammation, and fibrosis, without any changes in body weight. Improved NASH progression in HIIT mice was accompanied by a substantial decrease in the frequency of pro-inflammatory infiltrating, monocyte-derived macrophages in the liver and reduced myeloid progenitor populations in the bone marrow. Notably, an acute bout of MIT or HIIT exercise had no effect on the intrahepatic and splenic immune cell populations. In addition, bulk mRNA sequencing of the entire liver tissue showed a pattern of gene expression confirming that HIIT was more effective than MIT in improving liver inflammation and lipid biosynthesis. Conclusions Our data suggest that exercise lessens hepatic inflammation during NASH by reducing the accumulation of hepatic monocyte-derived inflammatory macrophages and bone marrow precursor cells. Our findings also indicate that HIIT is superior to MIT in ameliorating the disease in a dietary mouse model of NASH. High-intensity is more effective than moderate-intensity exercise at reducing NASH. High-intensity exercise lowers the infiltration of inflammatory macrophages in the liver. Reduced macrophage accumulation was associated with lower progenitor cells.
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Affiliation(s)
- Gavin Fredrickson
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Fanta Barrow
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Katrina Dietsche
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Preethy Parthiban
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Saad Khan
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada; Division of Cellular & Molecular Biology, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Sacha Robert
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Maya Demirchian
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Hailey Rhoades
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Haiguang Wang
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Oyedele Adeyi
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Xavier S Revelo
- Department of Integrative Biology & Physiology, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA.
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McCoin CS, Von Schulze A, Allen J, Fuller KNZ, Xia Q, Koestler DC, Houchen CJ, Maurer A, Dorn GW, Shankar K, Morris EM, Thyfault JP. Sex modulates hepatic mitochondrial adaptations to high-fat diet and physical activity. Am J Physiol Endocrinol Metab 2019; 317:E298-E311. [PMID: 31039007 PMCID: PMC6732468 DOI: 10.1152/ajpendo.00098.2019] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 04/29/2019] [Accepted: 04/29/2019] [Indexed: 02/06/2023]
Abstract
The impact of sexual dimorphism and mitophagy on hepatic mitochondrial adaptations during the treatment of steatosis with physical activity are largely unknown. Here, we tested if deficiencies in liver-specific peroxisome proliferative activated-receptor-γ coactivator-1α (PGC-1α), a transcriptional coactivator of biogenesis, and BCL-2/ADENOVIRUS EIB 19-kDa interacting protein (BNIP3), a mitophagy regulator, would impact hepatic mitochondrial adaptations (respiratory capacity, H2O2 production, mitophagy) to a high-fat diet (HFD) and HFD plus physical activity via voluntary wheel running (VWR) in both sexes. Male and female wild-type (WT), liver-specific PGC-1α heterozygote (LPGC-1α), and BNIP3 null mice were thermoneutral housed (29-31°C) and divided into three groups: sedentary-low-fat diet (LFD), 16 wk of (HFD), or 16 wk of HFD with VWR for the final 8 wk (HFD + VWR) (n = 5-7/sex/group). HFD did not impair mitochondrial respiratory capacity or coupling in any group; however, HFD + VWR significantly increased maximal respiratory capacity only in WT and PGC-1α females. Males required VWR to elicit mitochondrial adaptations that were inherently present in sedentary females including greater mitochondrial coupling control and reduced H2O2 production. Females had overall reduced markers of mitophagy, steatosis, and liver damage. Steatosis and markers of liver injury were present in sedentary male mice on the HFD and were effectively reduced with VWR despite no resolution of steatosis. Overall, reductions in PGC-1α and loss of BNIP3 only modestly impacted mitochondrial adaptations to HFD and HFD + VWR with the biggest effect seen in BNIP3 females. In conclusion, hepatic mitochondrial adaptations to HFD and treatment of HFD-induced steatosis with VWR are more dependent on sex than PGC-1α or BNIP3.
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Affiliation(s)
- Colin S McCoin
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
- Kansas City Veterans Affairs Medical Center , Kansas City, Kansas
| | - Alex Von Schulze
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
- Kansas City Veterans Affairs Medical Center , Kansas City, Kansas
| | - Julie Allen
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
- Kansas City Veterans Affairs Medical Center , Kansas City, Kansas
| | - Kelly N Z Fuller
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
| | - Qing Xia
- Department of Biostatistics, University of Kansas Medical Center , Kansas City, Kansas
| | - Devin C Koestler
- Department of Biostatistics, University of Kansas Medical Center , Kansas City, Kansas
| | - Claire J Houchen
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
| | - Adrianna Maurer
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
| | - Gerald W Dorn
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine , St. Louis, Missouri
| | - Kartik Shankar
- Arkansas Children's Nutrition Center and the Department of Pediatrics, University of Arkansas for Medical Sciences , Little Rock, Arizona
| | - E Matthew Morris
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
- Kansas City Veterans Affairs Medical Center , Kansas City, Kansas
| | - John P Thyfault
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
- Kansas City Veterans Affairs Medical Center , Kansas City, Kansas
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Fuller SE, Huang TY, Simon J, Batdorf HM, Essajee NM, Scott MC, Waskom CM, Brown JM, Burke SJ, Collier JJ, Noland RC. Low-intensity exercise induces acute shifts in liver and skeletal muscle substrate metabolism but not chronic adaptations in tissue oxidative capacity. J Appl Physiol (1985) 2019; 127:143-156. [PMID: 31095457 PMCID: PMC6692746 DOI: 10.1152/japplphysiol.00820.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 04/23/2019] [Accepted: 05/08/2019] [Indexed: 02/08/2023] Open
Abstract
Adaptations in hepatic and skeletal muscle substrate metabolism following acute and chronic (6 wk; 5 days/wk; 1 h/day) low-intensity treadmill exercise were tested in healthy male C57BL/6J mice. Low-intensity exercise maximizes lipid utilization; therefore, we hypothesized pathways involved in lipid metabolism would be most robustly affected. Acute exercise nearly depleted liver glycogen immediately postexercise (0 h), whereas hepatic triglyceride (TAG) stores increased in the early stages after exercise (0-3 h). Also, hepatic peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) gene expression and fat oxidation (mitochondrial and peroxisomal) increased immediately postexercise (0 h), whereas carbohydrate and amino acid oxidation in liver peaked 24-48 h later. Alternatively, skeletal muscle exhibited a less robust response to acute exercise as stored substrates (glycogen and TAG) remained unchanged, induction of PGC-1α gene expression was delayed (up at 3 h), and mitochondrial substrate oxidation pathways (carbohydrate, amino acid, and lipid) were largely unaltered. Peroxisomal lipid oxidation exhibited the most dynamic changes in skeletal muscle substrate metabolism after acute exercise; however, this response was also delayed (peaked 3-24 h postexercise), and expression of peroxisomal genes remained unaffected. Interestingly, 6 wk of training at a similar intensity limited weight gain, increased muscle glycogen, and reduced TAG accrual in liver and muscle; however, substrate oxidation pathways remained unaltered in both tissues. Collectively, these results suggest changes in substrate metabolism induced by an acute low-intensity exercise bout in healthy mice are more rapid and robust in liver than in skeletal muscle; however, training at a similar intensity for 6 wk is insufficient to induce remodeling of substrate metabolism pathways in either tissue. NEW & NOTEWORTHY Effects of low-intensity exercise on substrate metabolism pathways were tested in liver and skeletal muscle of healthy mice. This is the first study to describe exercise-induced adaptations in peroxisomal lipid metabolism and also reports comprehensive adaptations in mitochondrial substrate metabolism pathways (carbohydrate, lipid, and amino acid). Acute low-intensity exercise induced shifts in mitochondrial and peroxisomal metabolism in both tissues, but training at this intensity did not induce adaptive remodeling of metabolic pathways in healthy mice.
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Affiliation(s)
- Scott E Fuller
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center , Baton Rouge, Louisiana
- School of Kinesiology, University of Louisiana at Lafayette , Lafayette, Louisiana
| | - Tai-Yu Huang
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center , Baton Rouge, Louisiana
| | - Jacob Simon
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center , Baton Rouge, Louisiana
| | - Heidi M Batdorf
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center , Baton Rouge, Louisiana
- Laboratory of Immunogenetics, Pennington Biomedical Research Center , Baton Rouge, Louisiana
- Laboratory of Islet Biology and Inflammation, Pennington Biomedical Research Center , Baton Rouge, Louisiana
| | - Nabil M Essajee
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center , Baton Rouge, Louisiana
| | - Matthew C Scott
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center , Baton Rouge, Louisiana
| | - Callie M Waskom
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center , Baton Rouge, Louisiana
| | - John M Brown
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center , Baton Rouge, Louisiana
| | - Susan J Burke
- Laboratory of Immunogenetics, Pennington Biomedical Research Center , Baton Rouge, Louisiana
| | - J Jason Collier
- Laboratory of Islet Biology and Inflammation, Pennington Biomedical Research Center , Baton Rouge, Louisiana
| | - Robert C Noland
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center , Baton Rouge, Louisiana
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Orang Z, Mozaffari-Khosravi H, Sivandzadeh G, Pantovic A. The effect of omega-3 supplementation on glycemic indices and lipid profile in type 2 diabetic patients with non-alcoholic fatty liver disease: A double-blind, randomized, clinical trial. MEDITERRANEAN JOURNAL OF NUTRITION AND METABOLISM 2019. [DOI: 10.3233/mnm-180265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Zahra Orang
- Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Hassan Mozaffari-Khosravi
- Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - GholamReza Sivandzadeh
- Department of Internal Medicine, Gastroenterohepatology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ana Pantovic
- Centre of Research Excellence in Nutrition and Metabolism, Institute for Medical Research, University of Belgrade, Serbia
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Von Schulze A, McCoin CS, Onyekere C, Allen J, Geiger P, Dorn GW, Morris EM, Thyfault JP. Hepatic mitochondrial adaptations to physical activity: impact of sexual dimorphism, PGC1α and BNIP3-mediated mitophagy. J Physiol 2018; 596:6157-6171. [PMID: 30062822 PMCID: PMC6292817 DOI: 10.1113/jp276539] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 07/18/2018] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS Hepatic mitochondrial adaptations to physical activity may be regulated by mitochondrial biogenesis (PGC1α) and mitophagy (BNIP3). Additionally, these adaptations may be sex-dependent. Chronic increase in physical activity lowers basal mitochondrial respiratory capacity in mice. Female mice have higher hepatic electron transport system protein content, elevated respiratory capacity, lowered mitophagic flux, and emit less mitochondrial H2 O2 independent of physical activity. Males require chronic daily physical activity to attain a similar mitochondrial phenotype compared to females. In contrast, females have limited hepatic adaptations to chronic physical activity. Livers deficient in PGC1α and BNIP3 display similar mitochondrial adaptations to physical activity to those found in wild-type mice. ABSTRACT Hepatic mitochondrial adaptations to physical activity may be regulated by biogenesis- and mitophagy-associated pathways in a sex-dependent manner. Here, we tested if mice with targeted deficiencies in liver-specific peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α; LPGC1α+/- ) and BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3)-mediated mitophagy (BNIP3-/- ) would have reduced physical activity-induced adaptations in respiratory capacity, H2 O2 emission and mitophagy compared to wild-type (WT) controls and if these effects were impacted by sex. Male and female WT, LPGC1α+/- and BNIP3-/- C57BL6/J mice were divided into groups that remained sedentary or had access to daily physical activity via voluntary wheel running (VWR) (n = 6-10/group) for 4 weeks. Mice had ad libitum access to low-fat diet and water. VWR reduced basal mitochondrial respiration, increased mitochondrial coupling and altered ubiquitin-mediated mitophagy in a sex-specific manner in WT mice. Female mice of all genotypes displayed higher electron transport system content, displayed increased ADP-stimulated respiration, produced less mitochondrially derived reactive oxygen species, exhibited reduced mitophagic flux, and were less responsive to VWR compared to males. Males responded more robustly to VWR-induced changes in hepatic mitochondrial function resulting in a match to adaptations found in females. Deficiencies in PGC1α and BNIP3 alone did not largely alter mitochondrial adaptations to VWR. However, VWR restored sex-dependent abnormalities in mitophagic flux in LPGC1α+/- . Finally, BNIP3-/- mice had elevated mitochondrial content and increased mitochondrial respiration putatively through repressed mitophagic flux. In conclusion, hepatic mitochondrial adaptations to physical activity are more dependent on sex than PGC1α and BNIP3.
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Affiliation(s)
- Alex Von Schulze
- Molecular and Integrative PhysiologyUniversity of Kansas Medical CenterKansas CityKS66160USA
- Kansas City VA Medical CenterKansas CityMO64128USA
| | - Colin S. McCoin
- Molecular and Integrative PhysiologyUniversity of Kansas Medical CenterKansas CityKS66160USA
- Kansas City VA Medical CenterKansas CityMO64128USA
| | - Chiemela Onyekere
- Molecular and Integrative PhysiologyUniversity of Kansas Medical CenterKansas CityKS66160USA
| | - Julie Allen
- Molecular and Integrative PhysiologyUniversity of Kansas Medical CenterKansas CityKS66160USA
- Kansas City VA Medical CenterKansas CityMO64128USA
| | - Paige Geiger
- Molecular and Integrative PhysiologyUniversity of Kansas Medical CenterKansas CityKS66160USA
| | - Gerald W. Dorn
- Center for PharmacogenomicsDepartment of Internal MedicineWashington University School of MedicineSt LouisMO63110USA
| | - E. Matthew Morris
- Molecular and Integrative PhysiologyUniversity of Kansas Medical CenterKansas CityKS66160USA
- Kansas City VA Medical CenterKansas CityMO64128USA
| | - John P. Thyfault
- Molecular and Integrative PhysiologyUniversity of Kansas Medical CenterKansas CityKS66160USA
- Kansas City VA Medical CenterKansas CityMO64128USA
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Kobyliak N, Falalyeyeva T, Bodnar P, Beregova T. Probiotics Supplemented with Omega-3 Fatty Acids are More Effective for Hepatic Steatosis Reduction in an Animal Model of Obesity. Probiotics Antimicrob Proteins 2018; 9:123-130. [PMID: 27660157 DOI: 10.1007/s12602-016-9230-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Today probiotics have been suggested as a treatment for the prevention of NAFLD. Omega-3 fatty acid supplementation may have beneficial effects in regulating hepatic lipid metabolism, adipose tissue function and inflammation. The present study was designed to determine whether probiotics plus omega-3 are superior to probiotics alone on the monosodium glutamate (MSG)-induced NAFLD model in rats. We included 60 rats divided into four groups, 15 animals in each. Rats of group I were intact. Newborn rats of groups II-IV were injected with MSG. The III (Symbiter) group received 2.5 ml/kg of multiprobiotic "Symbiter" containing concentrated biomass of 14 probiotic bacteria genera. The IV (Symbiter-Omega) groups received "Symbiter-Omega" combination of probiotic biomass supplemented with flax and wheat germ oil (250 mg of each, concentration of omega-3 fatty acids 1-5 %). In both interventional groups reduction in total NAS score was observed. Supplementation of alive probiotic mixture with omega-3 fatty acids lead to 20 % higher decrease in steatosis score (0.73 ± 0.11 vs 0.93 ± 0.22, p = 0.848) and reduction by 16.6 % of triglycerides content in liver as compared to probiotic alone. Our study demonstrated more pronounced reduction in hepatic steatosis and hepatic lipid accumulation after treatment with combination of alive probiotics and omega-3 as compared to probiotics alone.
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Affiliation(s)
- Nazarii Kobyliak
- Bogomolets National Medical University, T. Shevchenko Boulevard, 13, Kiev, 01601, Ukraine.
| | - Tetyana Falalyeyeva
- Taras Shevchenko National University of Kyiv, Volodymyrska Str., 64/13, Kiev, 01601, Ukraine
| | - Petro Bodnar
- Bogomolets National Medical University, T. Shevchenko Boulevard, 13, Kiev, 01601, Ukraine
| | - Tetyana Beregova
- Taras Shevchenko National University of Kyiv, Volodymyrska Str., 64/13, Kiev, 01601, Ukraine
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Takahashi H, Kotani K, Tanaka K, Egucih Y, Anzai K. Therapeutic Approaches to Nonalcoholic Fatty Liver Disease: Exercise Intervention and Related Mechanisms. Front Endocrinol (Lausanne) 2018; 9:588. [PMID: 30374329 PMCID: PMC6196235 DOI: 10.3389/fendo.2018.00588] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/17/2018] [Indexed: 12/16/2022] Open
Abstract
Exercise training ameliorates nonalcoholic fatty liver disease (NAFLD) as well as obesity and metabolic syndrome. Although it is difficult to eliminate the effects of body weight reduction and increased energy expenditure-some pleiotropic effects of exercise training-a number of studies involving either aerobic exercise training or resistance training programs showed ameliorations in NAFLD that are independent of the improvements in obesity and insulin resistance. In vivo studies have identified effects of exercise training on the liver, which may help to explain the "direct" or "independent" effect of exercise training on NAFLD. Exercise training increases peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) expression, improves mitochondrial function and leads to reduced hepatic steatosis, inflammation, fibrosis, and tumor genesis. Crosstalk between the liver and adipose tissue, skeletal muscle and the microbiome is also a possible mechanism for the effect of exercise training on NAFLD. Although numerous studies have reported benefits of exercise training on NAFLD, the optimal duration and intensity of exercise for the prevention or treatment of NAFLD have not been established. Maintaining adherence of patients with NAFLD to exercise training regimes is another issue to be resolved. The use of comprehensive analytical approaches to identify biomarkers such as hepatokines that specifically reflect the effect of exercise training on liver functions might help to monitor the effect of exercise on NAFLD, and thereby improve adherence of these patients to exercise training. Exercise training is a robust approach for alleviating the pathogenesis of NAFLD, although further clinical and experimental studies are required.
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Affiliation(s)
- Hirokazu Takahashi
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga, Japan
- Liver Center, Saga University Hospital, Saga University, Saga, Japan
| | - Kazuhiko Kotani
- Division of Community and Family Medicine, Center for Community Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Kenichi Tanaka
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga, Japan
| | - Yuichiro Egucih
- Liver Center, Saga University Hospital, Saga University, Saga, Japan
| | - Keizo Anzai
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga, Japan
- *Correspondence: Keizo Anzai
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Linden MA, Fletcher JA, Morris EM, Meers GM, Laughlin MH, Booth FW, Sowers JR, Ibdah JA, Thyfault JP, Rector RS. Treating NAFLD in OLETF rats with vigorous-intensity interval exercise training. Med Sci Sports Exerc 2015; 47:556-67. [PMID: 24983336 DOI: 10.1249/mss.0000000000000430] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND There is increasing use of high-intensity interval-type exercise training in the management of many lifestyle-related diseases. PURPOSE This study aimed to test the hypothesis that vigorous-intensity interval exercise is as effective as traditional moderate-intensity aerobic exercise training for nonalcoholic fatty liver disease (NAFLD) outcomes in obese, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. METHODS OLETF rats (age, 20 wk; n = 8-10 per group) were assigned to sedentary (O-SED), moderate-intensity exercise training (O-MOD EX; 20 m·min(-1), 15% incline, 60 min·d(-1), 5 d·wk(-1) of treadmill running), or vigorous-intensity interval exercise training (O-VIG EX; 40 m·min(-1), 15% incline, 6 × 2.5 min bouts per day, 5 d·wk(-1) of treadmill running) groups for 12 wk. RESULTS Both MOD EX and VIG EX effectively lowered hepatic triglycerides, serum alanine aminotransferase (ALT), perivenular fibrosis, and hepatic collagen 1α1 messenger RNA (mRNA) expression (vs O-SED, P < 0.05). In addition, both interventions increased hepatic mitochondrial markers (citrate synthase activity and fatty acid oxidation) and suppressed markers of de novo lipogenesis (fatty acid synthase, acetyl coenzyme A carboxylase, Elovl fatty acid elongase 6, and steroyl CoA desaturase-1), whereas only MOD EX increased hepatic mitochondrial Beta-hydroxyacyl-CoA dehydrogenase (β-HAD) activity and hepatic triglyceride export marker apoB100 and lowered fatty acid transporter CD36 compared with O-SED. Moreover, whereas total hepatic macrophage population markers (CD68 and F4/80 mRNA) did not differ among groups, MOD EX and VIG EX lowered M1 macrophage polarization markers (CD11c, interleukin-1β, and tumor necrosis factor α mRNA) and MOD EX increased M2 macrophage marker, CD206 mRNA, compared with O-SED. CONCLUSIONS The accumulation of 15 min·d(-1) of VIG EX for 12 wk had similar effectiveness as 60 min·d(-1) of MOD EX in the management of NAFLD in OLETF rats. These findings may have important health outcome implications as we work to design better exercise training programs for patients with NAFLD.
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Affiliation(s)
- Melissa A Linden
- 1Research Service-Harry S. Truman Memorial Veterans Medical Center, Columbia, MO; 2Department of Medicine, Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO; 3Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO; 4Department of Biomedical Sciences, University of Missouri, Columbia, MO; 5Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO; 6Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO; and 7Department of Medicine, Division of Endocrinology, University of Missouri, Columbia, MO
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Liu TW, Heden TD, Matthew Morris E, Fritsche KL, Vieira-Potter VJ, Thyfault JP. High-Fat Diet Alters Serum Fatty Acid Profiles in Obesity Prone Rats: Implications for In Vitro Studies. Lipids 2015; 50:997-1008. [PMID: 26318121 DOI: 10.1007/s11745-015-4061-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/10/2015] [Indexed: 12/27/2022]
Abstract
High-fat diets (HFD) are commonly used in rodents to induce obesity, increase serum fatty acids and induce lipotoxicity in various organs. In vitro studies commonly utilize individual free fatty acids (FFA) to study lipid exposure in an effort to model what is occurring in vivo; however, these approaches are not physiological as tissues are exposed to multiple fatty acids in vivo. Here we characterize circulating lipids in obesity-prone rats fed an HFD in both fasted and fed states with the goal of developing physiologically relevant fatty acid mixtures for subsequent in vitro studies. Rats were fed an HFD (60% kcal fat) or a control diet (10% kcal fat) for 3 weeks; liver tissue and both portal and systemic blood were collected. Fatty acid profiles and absolute concentrations of triglycerides (TAG) and FFA in the serum and TAG, diacylglycerol (DAG) and phospholipids in the liver were measured. Surprisingly, both systemic and portal serum TAG were ~40% lower in HFD-fed compared to controls. Overall, compared to the control diet, HFD feeding consistently induced an increase in the proportion of circulating polyunsaturated fatty acids (PUFA) with a concomitant decline in monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA) in both serum TAG and FFA. The elevations of PUFA were mostly attributed to increases in n-6 PUFA, linoleic acid and arachidonic acid. In conclusion, fatty acid mixtures enriched with linoleic and arachidonic acid in addition to SFA and MUFA should be utilized for in vitro studies attempting to model lipid exposures that occur during in vivo HFD conditions.
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Affiliation(s)
- Tzu-Wen Liu
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, 65211, USA. .,Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Timothy D Heden
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, 65211, USA. .,Department of Kinesiology, East Carolina University, Greenville, NC, 27843, USA.
| | - E Matthew Morris
- Molecular and Integrative Physiology, University of Kansas Medical Center, 2067 Hemenway Life Sciences and Innovation Center, MS: 3043, 3901 Rainbow Blvd, Kansas, KS, 66160, USA.
| | - Kevin L Fritsche
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, 65211, USA. .,Animal Sciences, University of Missouri, Columbia, MO, 65211, USA.
| | | | - John P Thyfault
- Molecular and Integrative Physiology, University of Kansas Medical Center, 2067 Hemenway Life Sciences and Innovation Center, MS: 3043, 3901 Rainbow Blvd, Kansas, KS, 66160, USA. .,Research Service, Kansas City VA Medical Center, Kansas, MO, 64128, USA.
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11
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Trefts E, Williams AS, Wasserman DH. Exercise and the Regulation of Hepatic Metabolism. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 135:203-25. [PMID: 26477916 DOI: 10.1016/bs.pmbts.2015.07.010] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The accelerated metabolic demands of the working muscle cannot be met without a robust response from the liver. If not for the hepatic response, sustained exercise would be impossible. The liver stores, releases, and recycles potential energy. Exercise would result in hypoglycemia if it were not for the accelerated release of energy as glucose. The energetic demands on the liver are largely met by increased oxidation of fatty acids mobilized from adipose tissue. Adaptations immediately following exercise facilitate the replenishment of glycogen stores. Pancreatic glucagon and insulin responses orchestrate the hepatic response during and immediately following exercise. Like skeletal muscle and other physiological systems, liver adapts to repeated demands of exercise by increasing its capacity to produce energy by oxidizing fat. The ability of regular physical activity to increase fat oxidation is protective and can reverse fatty liver disease. Engaging in regular physical exercise has broad ranging positive health implications including those that improve the metabolic health of the liver.
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Affiliation(s)
- Elijah Trefts
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Ashley S Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
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12
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Linden MA, Fletcher JA, Morris EM, Meers GM, Kearney ML, Crissey JM, Laughlin MH, Booth FW, Sowers JR, Ibdah JA, Thyfault JP, Rector RS. Combining metformin and aerobic exercise training in the treatment of type 2 diabetes and NAFLD in OLETF rats. Am J Physiol Endocrinol Metab 2014; 306:E300-10. [PMID: 24326426 PMCID: PMC3920010 DOI: 10.1152/ajpendo.00427.2013] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Here, we sought to compare the efficacy of combining exercise and metformin for the treatment of type 2 diabetes and nonalcoholic fatty liver disease (NAFLD) in hyperphagic, obese, type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. OLETF rats (age: 20 wk, hyperglycemic and hyperinsulinemic; n = 10/group) were randomly assigned to sedentary (O-SED), SED plus metformin (O-SED + M; 300 mg·kg(-1)·day(-1)), moderate-intensity exercise training (O-EndEx; 20 m/min, 60 min/day, 5 days/wk treadmill running), or O-EndEx + M groups for 12 wk. Long-Evans Tokushima Otsuka (L-SED) rats served as nonhyperphagic controls. O-SED + M, O-EndEx, and O-EndEx + M were effective in the management of type 2 diabetes, and all three treatments lowered hepatic steatosis and serum markers of liver injury; however, O-EndEx lowered liver triglyceride content and fasting hyperglycemia more than O-SED + M. In addition, exercise elicited greater improvements compared with metformin alone on postchallenge glycemic control, liver diacylglycerol content, hepatic mitochondrial palmitate oxidation, citrate synthase, and β-HAD activities and in the attenuation of markers of hepatic fatty acid uptake and de novo fatty acid synthesis. Surprisingly, combining metformin and aerobic exercise training offered little added benefit to these outcomes, and in fact, metformin actually blunted exercise-induced increases in complete mitochondrial palmitate oxidation and β-HAD activity. In conclusion, aerobic exercise training was more effective than metformin administration in the management of type 2 diabetes and NAFLD outcomes in obese hyperphagic OLETF rats. Combining therapies offered little additional benefit beyond exercise alone, and findings suggest that metformin potentially impairs exercise-induced hepatic mitochondrial adaptations.
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Affiliation(s)
- Melissa A Linden
- Research Service, Harry S. Truman Memorial Veterans Affairs Hospital
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13
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Bouzianas DG, Bouziana SD, Hatzitolios AI. Potential treatment of human nonalcoholic fatty liver disease with long-chain omega-3 polyunsaturated fatty acids. Nutr Rev 2013; 71:753-71. [PMID: 24148001 DOI: 10.1111/nure.12073] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in the Western world. Its prevalence has increased with the growing obesity epidemic, yet no definitive treatment has been developed, and optimal management remains a clinical challenge. Long-chain omega-3 polyunsaturated fatty acids (PUFAs) have recently been proposed as a potential treatment for liver inflammation associated with fat accumulation. PubMed literature and the ClinicalTrials.gov database were reviewed for the effects of omega-3 PUFA treatment on NAFLD, from mechanisms to the results of preclinical studies, human studies, and unreported ongoing clinical trials, using terms such as NAFLD, nonalcoholic steatohepatitis, omega-3 fatty acids, and fish oil. Articles published over the last 3-4 years were emphasized, and relevancy was ensured by scanning their abstracts. Preliminary studies have confirmed an ameliorative effect, yet the translation of promising early data into therapeutic interventions will have to await the results of larger, properly conducted, ongoing clinical trials.
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Affiliation(s)
- Dimitrios G Bouzianas
- First Propedeutic Department of Internal Medicine, Medical School, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
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14
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Haus JM, Solomon TPJ, Kelly KR, Fealy CE, Kullman EL, Scelsi AR, Lu L, Pagadala MR, McCullough AJ, Flask CA, Kirwan JP. Improved hepatic lipid composition following short-term exercise in nonalcoholic fatty liver disease. J Clin Endocrinol Metab 2013; 98:E1181-8. [PMID: 23616151 PMCID: PMC3701282 DOI: 10.1210/jc.2013-1229] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
CONTEXT Hepatic steatosis, insulin resistance, inflammation, low levels of polyunsaturated lipids, and adiponectin are implicated in the development and progression of nonalcoholic fatty liver disease (NAFLD). OBJECTIVE We examined the effects of short-term aerobic exercise on these metabolic risk factors. DESIGN AND PARTICIPANTS Obese individuals (N = 17, 34.3 ± 1.0 kg/m²) with clinically confirmed NAFLD were enrolled in a short-term aerobic exercise program that consisted of 7 consecutive days of treadmill walking at ~85% of maximal heart rate for 60 minutes per day. Preintervention and postintervention measures included hepatic triglyceride content, and a lipid saturation index and polyunsaturated lipid index (PUI) of the liver, obtained by (1)H magnetic resonance spectroscopy (N = 14). Insulin sensitivity was estimated from an oral glucose tolerance test (OGTT), and mononuclear cells were isolated to assess reactive oxygen species production during the OGTT. Circulating glucose, insulin, and high molecular weight (HMW) adiponectin were determined from plasma. MAIN OUTCOME Short-term aerobic exercise training improved hepatic lipid composition in patients with NAFLD. RESULTS Exercise training resulted in an increase in liver PUI (P < .05), increased insulin sensitivity (Matsuda Index: P < .05), HMW adiponectin (P < .05), and maximal oxygen consumption (P < .05). Reactive oxygen species production during the OGTT was reduced following exercise training (P < .05). HMW adiponectin was increased after the exercise program and the increase was positively correlated with the increase in liver PUI (r = 0.52, P = .05). Body weight remained stable during the program (P > .05). CONCLUSION Short-term exercise can target hepatic lipid composition, which may reduce the risk of NAFLD progression. The improvement in hepatic lipid composition may be driven by adiponectin.
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Affiliation(s)
- Jacob M Haus
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
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15
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Time course of the development of nonalcoholic Fatty liver disease in the Otsuka long-evans Tokushima Fatty rat. Gastroenterol Res Pract 2013; 2013:342648. [PMID: 23737763 PMCID: PMC3666266 DOI: 10.1155/2013/342648] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 03/28/2013] [Accepted: 04/17/2013] [Indexed: 02/07/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is considered a hepatic manifestation of metabolic syndrome. In this study, we investigated histological and biochemical changes in NAFLD and the gene expression involving de novo lipogenesis in Otsuka Long-Evans Tokushima fatty (OLETF) rats. We used OLETF rats and Long-Evans Tokushima Otsuka (LETO) rats as animal models of NAFLD and as controls, respectively. Consistent observations were made at 4-week intervals up to 50 weeks of age, and all rats were fed ad libitum with standard food. Biochemical and histological changes were observed, and gene expression involved in de novo lipogenesis was measured using real-time polymerase chain reactions. As a results hepatic micro- and macrovesicular steatosis and hepatocyte ballooning were evident in the OLETF rats at 22-38 weeks of age but disappeared after 42 weeks; no fibrosis or collagen deposition was observed. Gene expression involved in de novo lipogenesis followed a pattern similar to that of the histological changes. In conclusion, in the absence of dietary manipulation, hepatic steatosis in OLETF rats is evident at 22-38 weeks and declines after 42 weeks. Therefore, OLETF rats at 22-38 weeks are recommended as animal models of hepatic steatosis.
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16
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Backus RC, Thomas DG, Fritsche KL. Comparison of inferred fractions of n-3 and n-6 polyunsaturated fatty acids in feral domestic cat diets with those in commercial feline extruded diets. Am J Vet Res 2013; 74:589-97. [PMID: 23531067 DOI: 10.2460/ajvr.74.4.589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare presumed fatty acid content in natural diets of feral domestic cats (inferred from body fat polyunsatrated fatty acids content) with polyunsaturated fatty acid content of commercial feline extruded diets. SAMPLE Subcutaneous and intra-abdominal adipose tissue samples (approx 1 g) from previously frozen cadavers of 7 adult feral domestic cats trapped in habitats remote from human activity and triplicate samples (200 g each) of 7 commercial extruded diets representing 68% of market share obtained from retail stores. PROCEDURES Lipid, triacylglycerol, and phospholipid fractions in adipose tissue samples and ether extracts of diet samples were determined by gas chromatography of methyl esters. Triacylglycerol and phospholipid fractions in the adipose tissue were isolated by thin-layer chromatography. Diet samples were also analyzed for proximate contents. RESULTS For the adipose tissue samples, with few exceptions, fatty acids fractions varied only moderately with lipid fraction and site from which tissue samples were obtained. Linoleic, α-linolenic, arachidonic, eicosapentaenoic, and docosahexaenoic acid fractions were 15.0% to 28.2%, 4.5% to 18.7%, 0.9% to 5.0%, < 0.1% to 0.2%, and 0.6% to 1.7%, respectively. As inferred from the adipose findings, dietary fractions of docosahexaenoic and α-linolenic acid were significantly greater than those in the commercial feline diets, but those for linoleic and eicosapentaenoic acids were not significantly different. CONCLUSIONS AND CLINICAL RELEVANCE The fatty acid content of commercial extruded feline diets differed from the inferred content of natural feral cat diets, in which dietary n-3 and possibly n-6 polyunsaturated fatty acids were more abundant. The impact of this difference on the health of pet cats is not known.
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Affiliation(s)
- Robert C Backus
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA.
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Fealy CE, Haus JM, Solomon TPJ, Pagadala M, Flask CA, McCullough AJ, Kirwan JP. Short-term exercise reduces markers of hepatocyte apoptosis in nonalcoholic fatty liver disease. J Appl Physiol (1985) 2012; 113:1-6. [PMID: 22582214 DOI: 10.1152/japplphysiol.00127.2012] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Increased hepatocyte apoptosis is a hallmark of nonalcoholic fatty liver disease (NAFLD) and contributes to the profibrogenic state responsible for the progression to nonalcoholic steatohepatitis (NASH). Strategies aimed at reducing apoptosis may result in better outcomes for individuals with NAFLD. We therefore examined the effect of a short-term exercise program on markers of apoptosis-plasma cytokeratin 18 (CK18) fragments, alanine aminotransferase (ALT), aspartate aminotransferase (AST), soluble Fas (sFas), and sFas ligand (sFasL)-in 13 obese individuals with NAFLD [body mass index 35.2 ± 1.2 kg/m(2), >5% intrahepatic lipid (IHL) assessed by (1)H-MR spectroscopy]. Exercise consisted of treadmill walking for 60 min/day on 7 consecutive days at ∼85% of maximal heart rate. Additionally, subjects underwent an oral glucose tolerance test and a maximal oxygen consumption (Vo(2max)) test before and after the exercise intervention. The Matsuda index was used to assess insulin sensitivity. We observed significant decreases in CK18 fragments (558.4 ± 106.8 vs. 323.4 ± 72.5 U/l, P < 0.01) and ALT (30.2 ± 5.1 vs. 24.3 ± 4.8 U/l, P < 0.05), and an increase in whole body fat oxidation (49.3 ± 6.1 vs. 69.4 ± 7.1 mg/min, P < 0.05), while decreases in circulating sFasL approached statistical significance (66.5 ± 6.0 vs. 63.0 ± 5.7 pg/ml, P = 0.06), as did the relationship between percent change in circulating CK18 fragments and ALT (r = 0.55, P = 0.05). We also observed a significant correlation between changes in fat oxidation and circulating sFasL (rho = -0.65, P < 0.05). There was no change in IHL following the intervention (18.2 ± 2.5 vs. 17.5 ± 2.1%, NS). We conclude that short-term exercise reduces a circulatory marker of hepatocyte apoptosis in obese individuals with NAFLD and propose that changes in the proapoptotic environment may be mediated through improved insulin sensitivity and increased oxidative capacity.
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Affiliation(s)
- Ciaran E Fealy
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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