Effect Of Age And Aerobic Training Status On Plasma And Skeletal Muscle tPA And PAI-1

AMPD1 genotype, relative fiber type composition, training status, and gender were evaluated as contributing factors to the reported variation in AMP deaminase enzyme activity in healthy skeletal muscle. Multifactorial correlative analyses demonstrate that AMPD1 genotype has the greatest effect on enzyme activity. An AMPD1 mutant allele frequency of 13.7 and a 1.7% incidence of enzyme deficiency was found across 175 healthy subjects. Homozygotes for the AMPD1 normal allele have high enzyme activities, and heterozygotes display intermediate activities. When examined according to genotype, other factors were found to affect variability as follows: AMP deaminase activity in homozygotes for the normal allele exhibits a negative correlation with the relative percentage of type I fibers and training status. Conversely, residual AMP deaminase activity in homozygotes for the mutant allele displays a positive correlation with the relative percentage of type I fibers. Opposing correlations in different homozygous AMPD1 genotypes are likely due to relative fiber-type differences in the expression of AMPD1 and AMPD3 isoforms. Gender also contributes to variation in total skeletal muscle AMP deaminase activity, with normal homozygous and heterozygous women showing only 85–88% of the levels observed in genotype-matched men.

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Age and tissue specific differences in the development of acute insulin resistance following injury

Journal of Endocrinology ◽

10.1677/joe-09-0269 ◽

2009 ◽

Vol 203 (3) ◽

pp. 365-374 ◽

Cited By ~ 10

Author(s):

Lidong Zhai ◽

Joseph L Messina

Keyword(s):

Insulin Resistance ◽

Skeletal Muscle ◽

Insulin Signaling ◽

Intracellular Signaling ◽

Male Rats ◽

Hepatic Insulin Resistance ◽

Surgical Trauma ◽

Induce Insulin Resistance ◽

Old Rats ◽

Effect Of Age

Injuries, hemorrhage, sepsis, burn, and critical illnesses all induce insulin resistance, and insulin resistance is strongly associated with advancing age. However, the effect of age on injury induced insulin resistance is not well studied. We performed surgical trauma in male rats of three different ages (3-, 6-, and 10-weeks old). Rats were either hemorrhaged to a mean arterial pressure of 35–40 mmHg and subsequently maintained at that pressure for up to 90 min, or maintained without hemorrhage as controls. Results indicate that insulin-induced intracellular signaling was diminished in liver and skeletal muscle of 6- and 10-week old rats following trauma and hemorrhage. In even younger rats, immediately post-weaning (∼3 weeks of age), insulin signaling was lost in liver, but not in skeletal muscle. Glucocorticoids can play a role in the chronic development of insulin resistance. Our results demonstrate that corticosterone levels were increased in 6- and 10-week old animals following hemorrhage, but little change was measured in 3-week old animals. Blockade of glucocorticoid synthesis prevented the development of insulin resistance in skeletal muscle, but not in liver of 6- and 10-week old rats. Moreover, skeletal muscle glucocorticoid receptor levels increased dramatically between 3 and 6 weeks of age. These results indicate that trauma and hemorrhage-induced hepatic insulin resistance occurs at all ages tested. However, there is no development of insulin resistance following trauma and hemorrhage in skeletal muscle of post-weaning rats. In skeletal muscle of 6- and 10-week old rats, inhibition of glucocorticoid levels prevents the development of insulin resistance.

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Skeletal Muscle CAP Expression Increases after Dietary Restriction and Aerobic Training in Women with a History of Gestational Diabetes

Journal of Gerontology & Geriatric Research ◽

10.4172/2167-7182.1000354 ◽

2016 ◽

Vol 5 (5) ◽

Author(s):

Alice S Ryan ◽

Monica C Serra

Keyword(s):

Skeletal Muscle ◽

Gestational Diabetes ◽

Dietary Restriction ◽

Aerobic Training ◽

History Of

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3P-0651 Influence of low and high intensity aerobic training on skeletal muscle capillarization

Atherosclerosis Supplements ◽

10.1016/s1567-5688(03)90871-3 ◽

2003 ◽

Vol 4 (2) ◽

pp. 205

Author(s):

N. Shono ◽

T. Matsubara ◽

M. Otonari ◽

K. Murakami ◽

M. Shindo ◽

...

Keyword(s):

Skeletal Muscle ◽

High Intensity ◽

Aerobic Training

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Effect of aerobic training status on both maximal lactate steady state and critical power

Applied Physiology Nutrition and Metabolism ◽

10.1139/h2012-047 ◽

2012 ◽

Vol 37 (4) ◽

pp. 736-743 ◽

Cited By ~ 8

Author(s):

Camila Coelho Greco ◽

Renato Aparecido Corrêa Caritá ◽

Jeanne Dekerle ◽

Benedito Sérgio Denadai

Keyword(s):

Steady State ◽

Oxygen Uptake ◽

Aerobic Fitness ◽

Maximal Oxygen Uptake ◽

Aerobic Training ◽

Critical Power ◽

Training Status ◽

Maximal Lactate Steady State ◽

Incremental Test ◽

Constant Work Rate

This study aimed at assessing the sensitivity of both maximal lactate steady state (MLSS) and critical power (CP) in populations of different aerobic training status to ascertain whether CP is as sensitive as MLSS to a change in aerobic fitness. Seven untrained subjects (UT) (maximal oxygen uptake = 37.4 ± 6.5 mL·kg–1·min–1) and 7 endurance cyclists (T) (maximal oxygen uptake = 62.4 ± 5.2 mL·kg–1·min–1) performed an incremental test for maximal oxygen uptake estimation and several constant work rate tests for MLSS and CP determination. MLSS, whether expressed in mL·kg–1·min–1 (T: 51.8 ± 5.7 vs. UT: 29.0 ± 6.1) or % maximal oxygen uptake (T: 83.1 ± 6.8 vs. UT: 77.1 ± 4.5), was significantly higher in the T group. CP expressed in mL·kg–1·min–1 (T: 56.8 ± 5.1 vs. UT: 33.1 ± 6.3) was significantly higher in the T group as well but no difference was found when expressed in % maximal oxygen uptake (T: 91.1 ± 4.8 vs. UT: 88.3 ± 3.6). Whether expressed in absolute or relative values, MLSS is sensitive to aerobic training status and a good measure of aerobic endurance. Conversely, the improvement in CP with years of training is proportional to those of maximal oxygen uptake. Thus, CP might be less sensitive than MLSS for depicting an enhancement in aerobic fitness.

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Home-based aerobic exercise training improves skeletal muscle oxidative metabolism in patients with metabolic myopathies

Journal of Applied Physiology ◽

10.1152/japplphysiol.00885.2015 ◽

2016 ◽

Vol 121 (3) ◽

pp. 699-708 ◽

Cited By ~ 18

Author(s):

Simone Porcelli ◽

Mauro Marzorati ◽

Lucia Morandi ◽

Bruno Grassi

Keyword(s):

Skeletal Muscle ◽

Infrared Spectroscopy ◽

Exercise Training ◽

Near Infrared Spectroscopy ◽

Oxidative Metabolism ◽

Near Infrared ◽

Aerobic Training ◽

Aerobic Exercise Training ◽

Low Intensity ◽

Home Based

Aerobic training can be effective in patients with mitochondrial myopathies (MM) and McArdle's disease (McA). The aim of the study was to use noninvasive functional evaluation methods, specifically aimed at skeletal muscle oxidative metabolism, to evaluate the effects of an aerobic exercise training (cycle ergometer, 12 wk, 4 days/wk, ∼65-70% of maximal heart rate) in 6 MM and 7 McA. Oxygen uptake and skeletal muscle vastus lateralis fractional O2 extraction by near-infrared spectroscopy were assessed during incremental and low-intensity constant work rate (CWR) exercises before (BEFORE) and at the end (AFTER) of training. Peak O2 uptake increased significantly with training both in MM [14.7 ± 1.2 vs. 17.6 ± 1.4 ml·kg−1·min−1 (mean ± SD)] and in McA (18.5 ± 1.8 ml·kg−1·min−1 vs. 21.6 ± 1.9). Peak skeletal muscle fractional O2 extraction increased with training both in MM (22.0 ± 6.7 vs. 32.6 ± 5.9%) and in McA (18.5 ± 6.2 vs. 37.2 ± 7.2%). During low-intensity CWR in both MM and McA: V̇o2 kinetics became faster in AFTER, but only in the patients with slow V̇o2 kinetics in BEFORE; the transient overshoot in fractional O2 extraction kinetics disappeared. The level of habitual physical activity was not higher 3 mo after training (FOLLOW-UP vs. PRE). In MM and McA patients a home-based aerobic training program significantly attenuated the impairment of skeletal muscle oxidative metabolism and improved variables associated with exercise tolerance. Our findings indicate that in MM and McA patients near-infrared spectroscopy and V̇o2 kinetics can effectively detect the functional improvements obtained by training.

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