Restoration of Motor Unit Properties and Fiber Type Distribution in Reinnervated Axolotl Skeletal Muscle

1993 ◽  
Vol 158 (2) ◽  
pp. 288-300 ◽  
Author(s):  
G.S. Bewick ◽  
P.S. Zammit ◽  
D.A. Tonge
Keyword(s):  
Skeletal Muscle ◽  
Motor Unit ◽  
Fiber Type ◽  
Type Distribution ◽  
Fiber Type Distribution

scholarly journals Skeletal muscle fiber size and fiber type distribution in human cancer: Effects of weight loss and relationship to physical function

2016 ◽  
Vol 35 (6) ◽  
pp. 1359-1365 ◽  
Author(s):  
Michael J. Toth ◽  
Damien M. Callahan ◽  
Mark S. Miller ◽  
Timothy W. Tourville ◽  
Sarah B. Hackett ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Weight Loss ◽  
Physical Function ◽  
Muscle Fiber ◽  
Human Cancer ◽  
Fiber Type ◽  
Skeletal Muscle Fiber ◽  
Type Distribution ◽  
Fiber Size ◽  
Fiber Type Distribution

Fatty acid profile of skeletal muscle phospholipids in trained and untrained young men

2000 ◽  
Vol 279 (4) ◽  
pp. E744-E751 ◽  
Author(s):  
Agneta Andersson ◽  
Anders Sjödin ◽  
Anu Hedman ◽  
Roger Olsson ◽  
Bengt Vessby
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Fatty Acid Profile ◽  
Acid Composition ◽  
Fiber Type ◽  
Young Men ◽  
Trained Group ◽  
Type Distribution ◽  
Fiber Type Distribution

Endurance trained ( n = 14) and untrained young men ( n = 15) were compared regarding the fatty acid profile of the vastus lateralis muscle after 8 wk on diets with a similar fatty acid composition. The skeletal muscle phospholipids in the trained group contained lower proportions of palmitic acid (16:0) (−12.4%, P < 0.001) and di-homo-γ-linolenic acid [20:3(n-6)] (−15.3%, P = 0.018), a lower n-6-to-n-3 ratio (−42.0%, P = 0.015), higher proportions of stearic acid (18:0) (+9.8%, P = 0.004) and sum of n-3 polyunsaturated fatty acids (+33.8%, P = 0.009), and a higher ratio between 20:4(n-6) to 20:3(n-6) (+18.4%, P = 0.006) compared with those in the untrained group. The group differences in 16:0, 20:3(n-6), 18:0/16:0, and 20:4(n-6)/20:3(n-6) were independent of fiber-type distribution. The trained group also showed a lower proportion of 16:0 (−7.9%, P < 0.001) in skeletal muscle triglycerides irrespective of fiber type. In conclusion, the fatty acid profile of the skeletal muscle differed between trained and untrained individuals, although the dietary fatty acid composition was similar. This difference was not explained by different fiber-type distribution alone but appears to be a direct consequence of changes in fatty acid metabolism due to the higher level of physical activity.

Changes in skeletal muscle in males and females following endurance training

2001 ◽  
Vol 79 (5) ◽  
pp. 386-392 ◽  
Author(s):  
S L Carter ◽  
C D Rennie ◽  
S J Hamilton ◽  
M A Tarnopolsky
Keyword(s):  
Skeletal Muscle ◽  
Endurance Training ◽  
Endurance Exercise ◽  
Fiber Type ◽  
Oxidative Potential ◽  
Muscle Enzyme ◽  
Type Distribution ◽  
Endurance Exercise Training ◽  
Fiber Type Distribution ◽  
Males And Females

Gender differences in substrate selection have been reported during endurance exercise. To date, no studies have looked at muscle enzyme adaptations following endurance exercise training in both genders. We investigated the effect of a 7-week endurance exercise training program on the activity of β-oxidation, tricarboxylic acid cycle and electron transport chain enzymes, and fiber type distribution in males and females. Training resulted in an increase in [Formula: see text]O2peak for both males and females of 17% and 22%, respectively (P < 0.001). The following muscle enzyme activities increased similarly in both genders: 3-β-hydroxyacyl CoA dehydrogenase (38%), citrate synthase (41%), succinate-cytochrome c oxidoreductase (41%), and cytochrome c oxidase (COX; 26%). The increase in COX activity was correlated (R2 = 0.52, P < 0.05) with the increase in [Formula: see text]O2peak/ fat free mass. Fiber area, size, and % area were not affected by training for either gender, however, males had larger Type II fibers (P < 0.05) and females had a greater Type I fiber % area (P < 0.05). Endurance training resulted in similar increases in skeletal muscle oxidative potential for both males and females. Training did not affect fiber type distribution or size in either gender.Key words: endurance training, oxidative potential, gender.

Genetic effects in human skeletal muscle fiber type distribution and enzyme activities

1986 ◽  
Vol 64 (9) ◽  
pp. 1245-1251 ◽  
Author(s):  
C. Bouchard ◽  
J. A. Simoneau ◽  
G. Lortie ◽  
M. R. Boulay ◽  
M. Marcotte ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Enzyme Activities ◽  
Fiber Type ◽  
Genetic Effect ◽  
Genetic Effects ◽  
Type I ◽  
Type Distribution ◽  
Fiber Type Distribution ◽  
Mz Twins

The purpose of the study was to estimate the genetic effect for skeletal muscle characteristics using pairs of nontwin brothers (n = 32), dizygotic (DZ) twins (n = 26), and monozygotic (MZ) twins (n = 35). They were submitted to a needle biopsy of the vastus lateralis for the determination of fiber type distribution (I, IIa, IIb) and the following enzymes were assayed for maximal activity: creatine kinase, hexokinase, phosphofructokinase (PFK), lactate dehydrogenase, malate dehydrogenase, 3-hydroxyacyl CoA dehydrogenase, and oxoglutarate dehydrogenase (OGDH). For the percentage of type I fibers, intraclass correlations were 0.33 (p < 0.05), 0.52 (p < 0.01), and 0.55 (p < 0.01) in brothers and DZ and MZ twins, respectively. MZ twins exhibited significant within-pair resemblance for all enzyme activities (0.30 ≤ r ≤ 0.68). In spite of these correlations, genetic analyses performed with the twin data alone indicated that there was no significant genetic effect for muscle fiber type I, IIa, and IIb distribution and fiber areas. Although there were significant correlations in MZ twins for all muscle enzyme activities, the often nonsignificant intraclass coefficients found in brothers and DZ twins suggest that variations in enzyme activities are highly related to common environmental conditions and nongenetic factors. However, genetic factors appear to be involved in the variation of regulatory enzymes of the glycolytic (PFK) and citric acid cycle (OGDH) pathways and in the variation of the oxidative to glycolytic activity ratio (PFK/OGDH ratio). Data show that these genetic effects reach only about 25–50% of the total phenotypic variation when data are adjusted for age and sex differences.

scholarly journals High-Throughput Muscle Fiber Typing From RNA Sequencing Data

2021 ◽  
Author(s):  
Nikolay Oskolkov ◽  
Malgorzata Santel ◽  
Ola Ekström ◽  
Gray J. Camp ◽  
Eri Miyamoto-Mikami ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Rna Sequencing ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Skeletal Muscle Fiber ◽  
Fiber Types ◽  
Sequencing Data ◽  
Gene Markers ◽  
Type Distribution ◽  
Fiber Type Distribution

Abstract BACKGROUND: Skeletal muscle fiber type distribution has implications for human health, muscle function and performance. This knowledge has been gathered using labor-intensive and costly methodology that limited these studies. Here we present a method based on muscle tissue RNA sequencing data (totRNAseq) to estimate the distribution of skeletal muscle fiber types from frozen human samples, allowing for a larger number of individuals to be tested.METHODS: By using single-nuclei RNA sequencing (snRNAseq) data as a reference, cluster expression signatures were produced by averaging gene expression of cluster gene markers and then applying these to totRNAseq data and inferring muscle fiber nuclei type via linear matrix decomposition. This estimate was then compared with fiber type distribution measured by ATPase staining or myosin heavy chain protein isoform distribution of 62 muscle samples in two independent cohorts (n = 39 and 22).RESULTS: The correlation between the sequencing-based method and the other two were rATPas = 0.65 [0.46 – 0.84], [95% CI] and rmyosin = 0.80 [0.71 – 0.89], with p = 7.96 x 10-6 and 8.06 x 10-6 respectively. The deconvolution inference of fiber type composition was accurate even for very low totRNAseq sequencing depths, i.e., down to an average of ~5.000 paired-end reads.CONCLUSIONS: This new method (https://github.com/OlaHanssonLab/PredictFiberType) consequently allows for measurement of fiber type distribution of a larger number of samples using totRNAseq in a cost and labor-efficient way. For the first time, it is now feasible to study the association between fiber type distribution and e.g. health outcomes in large well-powered studies.

The menopausal transition does not influence skeletal muscle capillary growth in response to cycle training in women

2021 ◽  
Author(s):  
Jorge Perez-Gomez ◽  
Nicolai Rytter ◽  
Camilla M. Mandrup ◽  
Jon Egelund ◽  
Bente Stallknecht ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Type Distribution ◽  
Capillary Growth ◽  
Menopausal Women ◽  
Fiber Type Distribution ◽  
Cycle Training ◽  
Post Menopausal

The influence of the menopausal transition, with a consequent loss of oestrogen, on capillary growth in response to exercise training remains unknown. In the present study, we evaluated the effect of a period of intense endurance training on skeletal muscle angiogenesis in late pre-menopausal and recently post-menopausal women with an age difference of <4 years. Skeletal muscle biopsies were obtained from the thigh muscle prior to and after 12 weeks of intense aerobic cycle training, and analyzed for capillarization, fiber type distribution and content of vascular endothelial growth factor (VEGF). At baseline, there was no difference in capillary per fiber ratio (C:F; 1.41 ± 0.22 vs 1.40 ± 0.30), capillary density (CD; 305±61 vs 336±52 mm2), muscle fiber area (MFA) or percentage distribution of muscle fiber type I (47.3±10.1 vs 49.3±15.1 %) and type II (52.7±10.1 vs 50.7±15.1%) between the pre- and post-menopausal women. The training period resulted in a similar increase in C:F in pre- and post-menopausal women (by 9.2 vs 12.1 %, respectively) and CD (by 6.9 vs 8.9 %, respectively), whereas MFA and fiber type distribution remained unaltered. Skeletal muscle VEGF protein content was similar between groups at baseline and increased to a similar extent with training (by 21.1 vs 27.2 %, respectively) in the pre- and post-menopausal women. In conclusion, the loss of oestrogen per se at menopause does not influence the capillary growth response to intense aerobic exercise training.

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