scholarly journals Exercise but not diet-induced weight loss decreases skeletal muscle inflammatory gene expression in frail obese elderly persons

2008 ◽  
Vol 105 (2) ◽  
pp. 473-478 ◽  
Author(s):  
Charles P. Lambert ◽  
Nicole R. Wright ◽  
Brian N. Finck ◽  
Dennis T. Villareal
Keyword(s):  
Skeletal Muscle ◽  
Weight Loss ◽  
Vastus Lateralis ◽  
Exercise Group ◽  
Fat Free Mass ◽  
Vastus Lateralis Muscle ◽  
Elderly Persons ◽  
Chronic Inflammatory Response ◽  
Tnf Α ◽  
Weight Loss Group

Many obese elderly persons have impaired physical function associated with an increased chronic inflammatory response. We evaluated 12 wk of exercise (aerobic and resistance) or 12 wk of weight loss (∼7% reduction) on skeletal muscle mRNAs for toll-like receptor-4 (TLR-4), mechanogrowth factor (MGF), TNF-α, and IL-6 in 16 obese (body mass index 38 ± 2 kg/m2) older (69 ± 1 yr) physically frail individuals. Vastus lateralis muscle biopsies were obtained at 0 and 12 wk and analyzed by real-time RT-PCR. Body composition was assessed by dual-energy x-ray absorptiometry. Body weight decreased (−7.5 ± 1.2 kg, P = 0.001) in the weight loss group but not in the exercise group (−0.3 ± 0.8 kg, P = 0.74). Fat-free mass (FFM) decreased (−2.9 ± 0.6 kg, P = 0.010) in the weight loss group and increased (1.6 ± 0.6 kg, P = 0.03) in the exercise group. Exercise resulted in a 37% decrease in TLR-4 mRNA ( P < 0.05) while weight loss had no significant effect. Additionally, exercise led to a significant (50%) decrease in IL-6 and TNF-α mRNA ( P < 0.05) while weight loss had no effect. Exercise increased MGF mRNA (∼2 fold, P < 0.05), but weight loss had no effect. In conclusion, exercise but not weight loss had a beneficial effect on markers of muscle inflammation and anabolism in frail obese elderly individuals.

scholarly journals Changes Induced by Physical Activity and Weight Loss in the Morphology of Intermyofibrillar Mitochondria in Obese Men and Women

2006 ◽  
Vol 91 (8) ◽  
pp. 3224-3227 ◽  
Author(s):  
Frederico G. S. Toledo ◽  
Simon Watkins ◽  
David E. Kelley
Keyword(s):  
Physical Activity ◽  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Weight Loss ◽  
Insulin Sensitivity ◽  
Lifestyle Modification ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Mitochondrial Content ◽  
The Mean

Abstract Context: In obesity, skeletal muscle insulin resistance may be associated with smaller mitochondria. Objective: Our objective was to examine the effect of a lifestyle-modification intervention on the content and morphology of skeletal muscle mitochondria and its relationship to insulin sensitivity in obese, insulin-resistant subjects. Design: In this prospective interventional study, intermyofibrillar mitochondrial content and size were quantified by transmission electron microscopy with quantitative morphometric analysis of biopsy samples from vastus lateralis muscle. Systemic insulin sensitivity was measured with euglycemic hyperinsulinemic clamps. Setting: The study took place at a university-based clinical research center. Participants: Eleven sedentary, overweight/obese volunteers without diabetes participated in the study. Intervention: Intervention included 16 wk of aerobic training with dietary restriction of 500-1000 kcal/d. Main Outcome Measures: We assessed changes in mitochondrial content and size and changes in insulin sensitivity. Results: The percentage of myofiber volume occupied by mitochondria significantly increased from 3.70 ± 0.31 to 4.87 ± 0.33% after intervention (P = 0.01). The mean individual increase was 42.5 ± 18.1%. There was also a change in the mean cross-sectional mitochondrial area, increasing from a baseline of 0.078 ± 0.007 to 0.091 ± 0.007 μm2 (P &lt; 0.01), a mean increase of 19.2 ± 6.1% per subject. These changes in mitochondrial size and content highly correlated with improvements in insulin resistance (r = 0.68 and 0.72, respectively; P = 0.01). Conclusions: A combined intervention of weight loss and physical activity in previously sedentary obese adults is associated with enlargement of mitochondria and an increase in the mitochondrial content in skeletal muscle. These findings indicate that in obesity with insulin resistance, ultrastructural mitochondrial plasticity is substantially retained and, importantly, that changes in the morphology of mitochondria are associated with improvements in insulin resistance.

scholarly journals Effects of weight loss and leptin on skeletal muscle in human subjects

2011 ◽  
Vol 301 (5) ◽  
pp. R1259-R1266 ◽  
Author(s):  
Kenneth M. Baldwin ◽  
Denis R. Joanisse ◽  
Fadia Haddad ◽  
Rochelle L. Goldsmith ◽  
Dympna Gallagher ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Weight Loss ◽  
Body Weight ◽  
Human Subjects ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Work Efficiency ◽  
Mhc I ◽  
Reduced Body ◽  
Lateralis Muscle

Maintenance of a 10% or greater reduced body weight results in decreases in the energy cost of low levels of physical activity beyond those attributable to the altered body weight. These changes in nonresting energy expenditure are due mainly to increased skeletal muscle work efficiency following weight loss and are reversed by the administration of the adipocyte-derived hormone leptin. We have also shown previously that the maintenance of a reduced weight is accompanied by a decrease in ratio of glycolytic (phosphofructokinase) to oxidative (cytochrome c oxidase) activity in vastus lateralis muscle that would suggest an increase in the relative expression of the myosin heavy chain I (MHC I) isoform. We performed analyses of vastus lateralis muscle needle biopsy samples to determine whether maintenance of an altered body weight was associated with changes in skeletal muscle metabolic properties as well as mRNA expression of different isoforms of the MHC and sarcoplasmic endoplasmic reticular Ca2+-dependent ATPase (SERCA) in subjects studied before weight loss and then again after losing 10% of their initial weight and receiving twice daily injections of either placebo or replacement leptin in a single blind crossover design. We found that the maintenance of a reduced body weight was associated with significant increases in the relative gene expression of MHC I mRNA that was reversed by the administration of leptin as well as an increase in the expression of SERCA2 that was not significantly affected by leptin. Leptin administration also resulted in a significant increase in the expression of the less MHC IIx isoform compared with subjects receiving placebo. These findings are consistent with the leptin-reversible increase in skeletal muscle chemomechanical work efficiency and decrease in the ratio of glycolytic/oxidative enzyme activities observed in subjects following dietary weight loss.

Eccentric contraction induces inflammatory responses in rat skeletal muscle: role of tumor necrosis factor-α

2010 ◽  
Vol 298 (3) ◽  
pp. R599-R607 ◽  
Author(s):  
Peng Liao ◽  
Jinping Zhou ◽  
Li Li Ji ◽  
Yong Zhang
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Damage ◽  
Time Course ◽  
Inflammatory Responses ◽  
Vastus Lateralis ◽  
Reactive Oxygen Species Generation ◽  
Eccentric Contraction ◽  
Exercise Group ◽  
Nuclear Accumulation ◽  
Tnf Α

Eccentric contraction (EC) is known to elicit inflammation and damage in skeletal muscle. Proinflammatory cytokine TNF-α plays an important role in this pathogenesis, but the time course of its response to EC and the regulatory mechanisms involved are not clear. The purpose of the study is twofold: 1) to investigate the gene expression of TNF-α in rat muscle during and after an acute bout of downhill running and the associated oxidoreductive (redox) changes; and 2) to examine whether EC activates muscle ubiquitin-proteolytic pathway resulting in necrosis and oxidative damage. Female Sprague-Dawley rats (age 3 mo) were randomly divided into five groups ( n = 6) that ran on treadmill at 25 m/min at −10% grade for 1 h ( group 1) or 2 h ( group 2) and were killed immediately; ran for 2 h and killed at 6 h after exercise ( group 3), ran for 2 h and killed at 24 h after exercise ( group 4); and killed at rest as controls ( group 5). TNF-α mRNA and protein content showed progressive increases in the deep portion of vastus lateralis (DVL) and gastrocnemius muscles during and after EC. These changes were accompanied by a progressive decrease of mitochondrial aconitase activity and NF-κB activation. After 2 h of exercise, elevated levels of serum TNF-α, endotoxin, creatine kinase, and lipid peroxidation marker were evident and persisted through 24 h postexercise. At 24 h, there were marked increases in H2O2 concentration, myleoperoxidase activity, and endotoxin level, along with nuclear accumulation of p65, in both muscles. mRNA level of ubiquitin-conjugating enzymes (E2)-14k was progressively upregulated during exercise and recovery, whereas the expression of the Toll-like receptor 4 (TLR4) in DVL was downregulated in both muscles. We conclude that prolonged EC induces TNF-α expression possibly due to NF-κB activation stimulated by increased reactive oxygen species generation and endotoxin release. These inflammatory and prooxidative responses may underlie the processes of muscle proteolysis and oxidative damage.

scholarly journals Triiodothyronine and leptin repletion in humans similarly reverse weight-loss-induced changes in skeletal muscle

2018 ◽  
Vol 315 (5) ◽  
pp. E771-E779 ◽  
Author(s):  
Michael Rosenbaum ◽  
Rochelle L. Goldsmith ◽  
Fadia Haddad ◽  
Kenneth M. Baldwin ◽  
Richard Smiley ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Weight Loss ◽  
Energy Homeostasis ◽  
Vastus Lateralis ◽  
Muscle Physiology ◽  
Vastus Lateralis Muscle ◽  
Work Efficiency ◽  
Mhc I ◽  
Muscle Work ◽  
Dietary Weight Loss

Subjects maintaining a ≥10% dietary weight loss exhibit decreased circulating concentrations of bioactive thyroid hormones and increased skeletal muscle work efficiency largely due to increased expression of more-efficient myosin heavy chain (MHC) isoforms (MHC I) and significantly mediated by the adipocyte-derived hormone leptin. The primary purpose of this study was to examine the effects of triiodothyronine (T3) repletion on energy homeostasis and skeletal muscle physiology in weight-reduced subjects and to compare these results with the effects of leptin repletion. Nine healthy in-patients with obesity were studied at usual weight (Wtinitial) and following a 10% dietary weight loss while receiving 5 wk of a placebo (Wt−10%placebo) or T3 (Wt−10%T3) in a single-blind crossover design. Primary outcome variables were skeletal muscle work efficiency and vastus lateralis muscle mRNA expression. These results were compared with the effects of leptin repletion in a population of 22 subjects, some of whom participated in a previous study. At Wt−10%placebo, skeletal muscle work efficiency and relative expression of the more-efficient/less-efficient MHC I/MHC II isoforms were significantly increased and the ratio of the less-efficient to the more-efficient sarco(endo)plasmic reticulum Ca2+-ATPase isoforms (SERCA1/SERCA2) was significantly decreased. These changes were largely reversed by T3 repletion to a degree similar to the changes that occurred with leptin repletion. These data support the hypothesis that the effects of leptin on energy expenditure in weight-reduced individuals are largely mediated by T3 and suggest that further study of the possible role of thyroid hormone repletion as adjunctive therapy to help sustain weight loss is needed.

scholarly journals Heightened muscle inflammation susceptibility may impair regenerative capacity in aging humans

2013 ◽  
Vol 115 (6) ◽  
pp. 937-948 ◽  
Author(s):  
Edward K. Merritt ◽  
Michael J. Stec ◽  
Anna Thalacker-Mercer ◽  
Samuel T. Windham ◽  
James M. Cross ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Cell Signaling ◽  
Vastus Lateralis ◽  
Receptor Expression ◽  
Vastus Lateralis Muscle ◽  
Regenerative Capacity ◽  
Muscle Inflammation ◽  
Tnf Α

The regenerative response of skeletal muscle to mechanically induced damage is impaired with age. Previous work in our laboratory suggests this may result from higher proinflammatory signaling in aging muscle at rest and/or a greater inflammatory response to damage. We, therefore, assessed skeletal muscle proinflammatory signaling at rest and 24 h after unaccustomed, loaded knee extension contractions that induced modest muscle damage (72% increase in serum creatine kinase) in a cohort of 87 adults across three age groups (AGE40, AGE61, and AGE76). Vastus lateralis muscle gene expression and protein cell signaling of the IL-6 and TNF-α pathways were determined by quantitative PCR and immunoblot analysis. For in vitro studies, cell signaling and fusion capacities were compared among primary myoblasts from young (AGE28) and old (AGE64) donors treated with TNF-α. Muscle expression was higher (1.5- to 2.1-fold) in AGE76 and AGE61 relative to AGE40 for several genes involved in IL-6, TNF-α, and TNF-like weak inducer of apoptosis signaling. Indexes of activation for the proinflammatory transcription factors signal transducer and activator of transcription-3 and NF-κB were highest in AGE76. Resistance loading reduced gene expression of IL-6 receptor, muscle RING finger 1, and atrogin-1, and increased TNF-like weak inducer of apoptosis receptor expression. Donor myoblasts from AGE64 showed impaired differentiation and fusion in standard media and greater NF-κB activation in response to TNF-α treatment (compared with AGE28). We show for the first time that human aging is associated with muscle inflammation susceptibility (i.e., higher basal state of proinflammatory signaling) that is present in both tissue and isolated myogenic cells and likely contributes to the impaired regenerative capacity of skeletal muscle in the older population.

scholarly journals Skeletal Muscle Angiopoietin-Like Protein 4 and Glucose Metabolism in Older Adults after Exercise and Weight Loss

Metabolites ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 354 ◽  
Author(s):  
Guoyan Li ◽  
Hefang Zhang ◽  
Alice S. Ryan
Keyword(s):  
Skeletal Muscle ◽  
Weight Loss ◽  
Mrna Expression ◽  
Body Fat ◽  
Vastus Lateralis ◽  
Lipoprotein Metabolism ◽  
Oral Glucose ◽  
Vastus Lateralis Muscle ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Angiopoietin-like protein 4 (ANGPTL4) is an adipokine that plays an important role in energy homoeostasis and lipid and lipoprotein metabolism. This study was designed to determine the effect of an exercise plus weight loss intervention on ANGPTL4 expression and its relationship with metabolic health. Thirty-five obese sedentary men (n = 18) and postmenopausal women (n = 17), (X ± SEM, age: 61 ± 1 years, BMI: 31.3 ± 0.7 kg/m2, VO2max: 21.7 ± 0.9 L/kg/min) completed a 6 month program of 3×/week aerobic exercise and 1×/week dietary instruction to induce weight loss (AEX + WL). Participants underwent vastus lateralis muscle biopsies, a hyperinsulinemic–euglycemic clamp, oral glucose tolerance tests and body composition testing. Basal skeletal muscle ANGPTL4 mRNA was lower in men than women (p < 0.01). Peroxisome proliferator-activated receptor (PPAR) alpha (PPARα) mRNA expression was higher in men than women (p < 0.05). There were no significance changes in serum or skeletal muscle ANGPTL4 (basal or insulin-stimulated) or muscle PPARα mRNA expression after AEX + WL. Muscle mRNA ANGPTL4 is correlated with serum ANGPTL4 (r = 0.41, p < 0.05), body fat (r = 0.64, p < 0.0001), and glucose utilization (r = 0.38, p < 0.05). AEX + WL does not change basal or insulin-stimulated skeletal muscle ANGPTL4 mRNA expression, suggesting other factors contribute to improved insulin sensitivity after the loss of body fat and improved fitness.

Effects of weight loss and physical activity on skeletal muscle mitochondrial function in obesity

2005 ◽  
Vol 288 (4) ◽  
pp. E818-E825 ◽  
Author(s):  
Elizabeth V. Menshikova ◽  
Vladimir B. Ritov ◽  
Frederico G. S. Toledo ◽  
Robert E. Ferrell ◽  
Bret H. Goodpaster ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Weight Loss ◽  
Nuclear Dna ◽  
Vastus Lateralis ◽  
Percutaneous Biopsy ◽  
Functional Improvement ◽  
Vastus Lateralis Muscle ◽  
Mt Dna ◽  
Principal Mechanism ◽  
Before And After

The current study was undertaken to address responsiveness of skeletal muscle mitochondrial electron transport chain (ETC) activity to weight loss (WL) and exercise in overweight or obese, sedentary volunteers. Fourteen middle-aged participants (7 male/7 female) had assessments of mitochondrial ETC activity and mitochondrial (mt)DNA in vastus lateralis muscle, obtained by percutaneous biopsy, before and after a 16-wk intervention. Mean WL was 9.7 (1.5%) and the mean increase in V̇o2 max was [means (SD)] 21.7 (3.7)%. Total ETC activity increased significantly, from 0.13 (0.02) to 0.19 (0.03) U/mU creatine kinase (CK; P < 0.001). ETC activity was also assessed in mitochondria isolated into subsarcolemmal (SSM) and intermyofibrillar (IMF-M) fractions. In response to intervention, there was a robust increase of ETC activity in SSM (0.028 (0.007) to 0.046 (0.011) U/mU CK, P < 0.001), and in IMF-M [0.101 (0.015) to 0.148 (0.018) U/mU CK, P < 0.005]. At baseline, the percentage of ETC activity contained in the SSM fraction was low and remained unchanged following intervention [19 ( 3 ) vs. 22 ( 2 )%], despite the increase in ETC activity. Also, muscle mtDNA content did not change significantly [1665 (213) vs. 1874 (214) mtDNA/nuclear DNA], denoting functional improvement rather than proliferation of mitochondria as the principal mechanism of enhanced ETC activity. Increases in ETC activity were correlated with energy expenditure during exercise sessions, and ETC activity in SSM correlated with insulin sensitivity after adjustment for V̇o2 max. In summary, skeletal muscle ETC activity is increased by WL and exercise in previously sedentary obese men and women. We conclude that improved skeletal muscle ETC activity following moderate WL and improved aerobic capacity contributes to associated alleviation of insulin resistance.

Muscle glycogen availability and temperature regulation in humans

1989 ◽  
Vol 66 (1) ◽  
pp. 72-78 ◽  
Author(s):  
L. Martineau ◽  
I. Jacobs
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Temperature Regulation ◽  
Vastus Lateralis ◽  
Water Immersion ◽  
Vastus Lateralis Muscle ◽  
Glycogen Concentration ◽  
Exercise Regimen ◽  
Before And After ◽  
Muscle Groups

The effects of intramuscular glycogen availability on human temperature regulation were studied in eight seminude subjects immersed in 18 degrees C water for 90 min or until rectal temperature (Tre) decreased to 35.5 degrees C. Each subject was immersed three times over a 3-wk period. Each immersion followed 2.5 days of a specific dietary and/or exercise regimen designed to elicit low (L), normal (N), or high (H) glycogen levels in large skeletal muscle groups. Muscle glycogen concentration was determined in biopsies taken from the vastus lateralis muscle before and after each immersion. Intramuscular glycogen concentration before the immersion was significantly different among the L, N, and H trials (P less than 0.01), averaging 247 +/- 15, 406 +/- 23, and 548 +/- 42 (SE) mmol glucose units.kg dry muscle-1, respectively. The calculated metabolic heat production during the first 30 min of immersion was significantly lower during L compared with N or H (P less than 0.05). The rate at which Tre decreased was more rapid during the L immersion than either N or H (P less than 0.05), and the time during the immersion at which Tre first began to decrease also appeared sooner during L than N or H. The results suggest that low skeletal muscle glycogen levels are associated with more rapid body cooling during water immersion in humans. Higher than normal muscle glycogen levels, however, do not increase cold tolerance.

Muscle blood flow during exercise in sedentary and trained hypothyroid rats

1995 ◽  
Vol 269 (6) ◽  
pp. H1949-H1954 ◽  
Author(s):  
R. M. McAllister ◽  
M. D. Delp ◽  
K. A. Thayer ◽  
M. H. Laughlin
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Muscle Blood Flow ◽  
Treadmill Running ◽  
Exercise Intolerance ◽  
Vastus Lateralis Muscle ◽  
Blood Flows ◽  
Vastus Intermedius

Hypothyroidism is characterized by exercise intolerance. We hypothesized that active muscle blood flow during in vivo exercise is inadequate in the hypothyroid state. Additionally, we hypothesized that endurance exercise training would restore normal blood flow during acute exercise. To test these hypotheses, rats were made hypothyroid (Hypo) over 3-4 mo with propylthiouracil. A subset of Hypo rats was trained (THypo) on a treadmill at 30 m/min (15% grade) for 60 min/day 5 days/wk over 10-15 wk. Hypothyroidism was evidenced by approximately 80% reductions in plasma triiodothyronine levels in Hypo and THypo and by 40-50% reductions in citrate synthase activities in high oxidative muscles in Hypo compared with euthyroid (Eut) rats. Training efficacy was indicated by increased (25-100%) citrate synthase activities in muscles of THypo vs. Hypo. Regional blood flows were determined by the radiolabeled microsphere method before exercise and at 1-2 min of treadmill running at 15 m/min (0% grade). Preexercise muscle blood flows were generally similar among groups. During exercise, however, flows were lower in Hypo than in Eut for high oxidative muscles such as the red section of vastus lateralis [277 +/- 24 and 153 +/- 13 (SE) ml.min-1.100 g-1 for Eut and Hypo, respectively; P < 0.01] and vastus intermedius (317 +/- 32 and 187 +/- 20 ml.min-1.100 g-1 for Eut and Hypo, respectively; P < 0.01) muscles. Training (THypo) did not normalize these flows (168 +/- 24 and 181 +/- 24 ml.min-1.100 g-1 for red section of vastus lateralis and vastus intermedius muscles, respectively). Blood flows to low oxidative muscle, such as the white section of vastus lateralis muscle, were similar among groups (21 +/- 5, 25 +/- 4, and 34 +/- 7 ml.min-1.100 g-1 for Eut, Hypo, and THypo, respectively; P = NS). These findings indicate that hypothyroidism is associated with reduced blood flow to skeletal muscle during exercise, suggesting that impaired delivery of nutrients to and/or removal of metabolites from skeletal muscle contributes to the poor exercise tolerance characteristic of hypothyroidism.

A single bout of exercise activates matrix metalloproteinase in human skeletal muscle

2007 ◽  
Vol 102 (6) ◽  
pp. 2346-2351 ◽  
Author(s):  
E. Rullman ◽  
H. Rundqvist ◽  
D. Wågsäter ◽  
H. Fischer ◽  
P. Eriksson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Matrix Metalloproteinase ◽  
Vastus Lateralis ◽  
Tissue Expression ◽  
Tissue Inhibitor Of Metalloproteinase ◽  
Vastus Lateralis Muscle ◽  
Protein Levels ◽  
Single Bout ◽  
Exercise Induced ◽  
Muscle Biopsies

The aims of this study were 1) to characterize changes in matrix metalloproteinase (MMP), endostatin, and vascular endothelial growth factor (VEGF)-A expression in skeletal muscle in response to a single bout of exercise in humans; and 2) to determine if any exchange of endostatin and VEGF-A between circulation and the exercising leg is associated with a change in the tissue expression or plasma concentration of these factors. Ten healthy males performed 65 min of cycle exercise, and muscle biopsies were obtained from the vastus lateralis muscle at rest and immediately and 120 min after exercise. In the muscle biopsies, measurements of mRNA expression levels of MMP-2, MMP-9, MMP-14, and tissue inhibitor of metalloproteinase; VEGF and endostatin protein levels; and MMP activities were performed. Femoral arterial and venous concentrations of VEGF-A and endostatin were determined before, during, and 120 min after exercise. A single bout of exercise increased MMP-9 mRNA and activated MMP-9 protein in skeletal muscle. No measurable increase of endostatin was observed in the skeletal muscle or in plasma following exercise. A concurrent increase in skeletal muscle VEGF-A mRNA and protein levels was induced by exercise, with no signs of peripheral uptake from the circulation. However, a decrease in plasma VEGF-A concentration occurred following exercise. Thus 1) a single bout of exercise activated the MMP system without any resulting change in tissue endostatin protein levels, and 2) the increased VEGF-A protein levels are due to changes in the skeletal muscle tissue itself. Other mechanisms are responsible for the observed exercise-induced decrease in VEGF-A in plasma.

Sign in / Sign up

Export Citation Format

Share Document