Satellite cell and myonuclear accretion is related to training-induced skeletal muscle fiber hypertrophy in young males and females

2021 ◽  
Author(s):  
Sidney Abou Sawan ◽  
Nathan Hodson ◽  
Paul Babits ◽  
Julia M. Malowany ◽  
Dinesh A. Kumbhare ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Exercise ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Whole Body ◽  
Type I ◽  
Type Ii ◽  
Young Males ◽  
Males And Females ◽  
Type Ii Fibers

Satellite cells (SC) play an integral role in the recovery from skeletal muscle damage and supporting muscle hypertrophy. Acute resistance exercise typically elevates type I and type II SC content 24-96 hours post-exercise in healthy young males, although comparable research in females is lacking. We aimed to elucidate whether sex-based differences exist in fiber type-specific SC content after resistance exercise in the untrained (UT) and trained (T) states. Ten young males (23.0 ± 4.0y) and females (23.0 ± 4.8y) completed an acute bout of resistance exercise before and after 8 weeks of whole-body resistance training. Muscle biopsies were taken from the vastus lateralis immediately prior to and 24 and 48-hours after each bout to determine SC and myonuclear content by immunohistochemistry. Males had greater SC associated with type II fibers (P ≤ 0.03). There was no effect of acute resistance exercise on SC content in either fiber type (P ≥ 0.58) for either sex, however, training increased SC in type II fibers (P < 0.01) irrespective of sex. The change in mean 0-48 h type II SC was positively correlated with muscle fiber hypertrophy in type II fibers (r = 0.47; P = 0.035). Furthermore, the change in myonuclei per fiber was positively correlated with type I and type II fiber hypertrophy (both r = 0.68; P < 0.01). Our results suggest that SC responses to acute and chronic resistance exercise are similar in males and females and that SC and myonuclear accretion is related to training-induced muscle fiber hypertrophy.

scholarly journals Satellite cell content is specifically reduced in type II skeletal muscle fibers in the elderly

2007 ◽  
Vol 292 (1) ◽  
pp. E151-E157 ◽  
Author(s):  
Lex B. Verdijk ◽  
René Koopman ◽  
Gert Schaart ◽  
Kenneth Meijer ◽  
Hans H. C. M. Savelberg ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Fiber Type ◽  
The Elderly ◽  
Type I ◽  
Type Ii ◽  
Fiber Area ◽  
Muscle Fiber Atrophy ◽  
Fiber Atrophy ◽  
Type Ii Fibers

Satellite cells (SC) are essential for skeletal muscle growth and repair. Because sarcopenia is associated with type II muscle fiber atrophy, we hypothesized that SC content is specifically reduced in the type II fibers in the elderly. A total of eight elderly (E; 76 ± 1 yr) and eight young (Y; 20 ± 1 yr) healthy males were selected. Muscle biopsies were collected from the vastus lateralis in both legs. ATPase staining and a pax7-antibody were used to determine fiber type-specific SC content (i.e., pax7-positive SC) on serial muscle cross sections. In contrast to the type I fibers, the proportion and mean cross-sectional area of the type II fibers were substantially reduced in E vs. Y. The number of SC per type I fiber was similar in E and Y. However, the number of SC per type II fiber was substantially lower in E vs. Y (0.044 ± 0.003 vs. 0.080 ± 0.007; P < 0.01). In addition, in the type II fibers, the number of SC relative to the total number of nuclei and the number of SC per fiber area were also significantly lower in E. This study is the first to show type II fiber atrophy in the elderly to be associated with a fiber type-specific decline in SC content. The latter is evident when SC content is expressed per fiber or per fiber area. The decline in SC content might be an important factor in the etiology of type II muscle fiber atrophy, which accompanies the loss of skeletal muscle with aging.

scholarly journals Phosphorylation of αB-crystallin and its cytoskeleton association differs in skeletal myofiber types depending on resistance exercise intensity and volume

2019 ◽  
Vol 126 (6) ◽  
pp. 1607-1618 ◽  
Author(s):  
Daniel Jacko ◽  
Käthe Bersiner ◽  
Jonas Hebchen ◽  
Markus de Marées ◽  
Wilhelm Bloch ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Exercise ◽  
Mechanical Stress ◽  
Fiber Type ◽  
Type I ◽  
Type Ii ◽  
Αb Crystallin ◽  
Serine 59 ◽  
Type I Fibers ◽  
Type Ii Fibers

αB-crystallin (CRYAB) is an important actor in the immediate cell stabilizing response following mechanical stress in skeletal muscle. Yet, only little is known regarding myofiber type-specific stress responses of CRYAB. We investigated whether the phosphorylation of CRYAB at serine 59 (pCRYABSer59) and its cytoskeleton association are influenced by varying load-intensity and -volume in a fiber type-specific manner. Male subjects were assigned to 1, 5, and 10 sets of different acute resistance exercise protocols: hypertrophy (HYP), maximum strength (MAX), strength endurance (SE), low intensity (LI), and three sets of maximum eccentric resistance exercise (ECC). Skeletal muscle biopsies were taken at baseline and 30 min after exercise. Western blot revealed an increase inpCRYABSer59only following 5 and 10 sets in groups HYP, MAX, SE, and LI as well as following 3 sets in the ECC group. In type I fibers, immunohistochemistry determined increasedpCRYABSer59in all groups. In type II fibers,pCRYABSer59only increased in MAX and ECC groups, with the increase in type II fibers exceeding that of type I fibers in ECC. Association of CRYAB andpCRYABSer59with the cytoskeleton reflected the fiber type-specific phosphorylation pattern. Phosphorylation of CRYAB and its association with the cytoskeleton in type I and II myofibers is highly specific in terms of loading intensity and volume. Most likely, this is based on specific recruitment patterns of the different myofiber entities due to the different resistance exercise loadings. We conclude thatpCRYABSer59indicates contraction-induced mechanical stress exposure of single myofibers in consequence of resistance exercise.NEW & NOTEWORTHY We determined that the phosphorylation of αB-crystallin at serine 59 (pCRYABSer59) after resistance exercise differs between myofiber types in a load- and intensity-dependent manner. The determination ofpCRYABSer59could serve as a marker indirectly indicating contractile involvement and applied mechanical stress on individual fibers. By that, it is possible to retrospectively assess the impact of resistance exercise loading on skeletal muscle fiber entities.

scholarly journals Influence of exercise contraction mode and protein supplementation on human skeletal muscle satellite cell content and muscle fiber growth

2014 ◽  
Vol 117 (8) ◽  
pp. 898-909 ◽  
Author(s):  
Jean Farup ◽  
Stine Klejs Rahbek ◽  
Simon Riis ◽  
Mikkel Holm Vendelbo ◽  
Frank de Paoli ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Whey Protein ◽  
Muscle Fiber ◽  
Satellite Cells ◽  
Fiber Type ◽  
Protein Supplementation ◽  
Type I ◽  
Type Ii ◽  
Type Ii Fibers

Skeletal muscle satellite cells (SCs) are involved in remodeling and hypertrophy processes of skeletal muscle. However, little knowledge exists on extrinsic factors that influence the content of SCs in skeletal muscle. In a comparative human study, we investigated the muscle fiber type-specific association between emergence of satellite cells (SCs), muscle growth, and remodeling in response to 12 wk unilateral resistance training performed as eccentric (Ecc) or concentric (Conc) resistance training ± whey protein (Whey, 19.5 g protein + 19.5 g glucose) or placebo (Placebo, 39 g glucose) supplementation. Muscle biopsies (vastus lateralis) were analyzed for fiber type-specific SCs, myonuclei, and fiber cross-sectional area (CSA). Following training, SCs increased with Conc in both type I and type II fibers ( P < 0.01) and exhibited a group difference from Ecc ( P < 0.05), which did not increase. Myonuclei content in type I fibers increased in all groups ( P < 0.01), while a specific accretion of myonuclei in type II fibers was observed in the Whey-Conc ( P < 0.01) and Placebo-Ecc ( P < 0.01) groups. Similarly, whereas type I fiber CSA increased independently of intervention ( P < 0.001), type II fiber CSA increased exclusively with Whey-Conc ( P < 0.01) and type II fiber hypertrophy correlated with whole muscle hypertrophy exclusively following Conc training ( P < 0.01). In conclusion, isolated concentric knee extensor resistance training appears to constitute a stronger driver of SC content than eccentric resistance training while type II fiber hypertrophy was accentuated when combining concentric resistance training with whey protein supplementation.

The Effects of Non-Weight Bearing on Skeletal Muscle in Older Rats: an Interrupted Bout versus an Uninterrupted Bout

2004 ◽  
Vol 5 (3) ◽  
pp. 195-202 ◽  
Author(s):  
Alissa Guildner Gehrke ◽  
Margaret Sheie Krull ◽  
Robin Shotwell McDonald ◽  
Tracy Sparby ◽  
Jessica Thoele ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Weight Bearing ◽  
Cross Sectional Area ◽  
Type I ◽  
Type Ii ◽  
Sectional Area ◽  
Cross Sectional ◽  
Age Related ◽  
Type Ii Fibers

Age-related changes in skeletal muscle, in combination with bed rest, may result in a poorer rehabilitation potential for an elderly patient. The purpose of this study was to determine the effects of non-weight bearing (hind limb unweighting [HU]) on the soleus and extensor digitorum longus (EDL) in older rats. Two non-weight bearing conditions were used: an uninterrupted bout of HU and an interrupted bout of HU. Twenty-one rats were randomly placed into 1 of 3 groups: control, interrupted HU (2 phases of 7 days of HU, separated by a 4-day weight-bearing phase) and an uninterrupted HU (18 uninterrupted days of HU). Following non-weight bearing, the soleus and EDL muscles were removed. Fiber type identification was performed by myofibrillar ATPase and cross-sectional area was determined. The findings suggest that any period of non-weight bearing leads to a decrease in muscle wet weight (19%-45%). Both type I and type II fibers of the soleus showed atrophy (decrease in cross-sectional area, 35%-44%) with an uninterrupted bout of non-weight bearing. Only the type II fibers of the soleus showed recovery with an interrupted bout of weight bearing. In the EDL, type II fibers were more affected by an uninterrupted bout of non-weight bearing (15% decrease in fiber size) compared to the type I fibers. EDL type II fibers showed more atrophy with interrupted bouts of non-weight bearing than with a single bout (a 40% compared to a 15% decrease). This study shows that initial weight bearing after an episode of non-weight bearing may be damaging to type II fibers of the EDL.

Muscle Fiber Type Distribution in the Normal Human Levator Veli Palatini Muscle

1998 ◽  
Vol 35 (5) ◽  
pp. 419-424 ◽  
Author(s):  
Jerald B. Moon ◽  
Sue Ann Thompson ◽  
Elise Jaeckel ◽  
John W. Canady
Keyword(s):  
Muscle Tissue ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Type I ◽  
Type Ii ◽  
Type Distribution ◽  
Levator Veli Palatini ◽  
Fiber Type Distribution ◽  
Type I Fibers ◽  
Type Ii Fibers

Objective This study examined the muscle fiber type distribution within the normal adult levator veli palatini muscle. Methods Levator veli palatini muscle tissue was harvested from the palates of 12 (seven female, five male) adult noncleft cadavers. Adjacent sections were stained for adenosine triphosphatase at pH 10.4 or 4.2. After mounting, magnifying, and photographing, Type I versus Type II fiber types were differentiated by the intensity of, or by the inhibition of, staining of matched fibers at each pH level. Type I fibers stained light at pH 10.4 and dark at pH 4.2, while Type II fibers stained light at pH 4.2 and dark at pH 10.4. Main outcome Measures The number of fibers counted for each specimen ranged from 60 to 616. The numbers of Type I and Type II stained fibers appearing in each muscle tissue sample were determined and expressed as a percentage of the total number of fibers identified. A few identified fibers could not be labelled as either Type I or Type II. Results The overall proportion of Type I fibers, averaged across all specimens, was 59.8%. Male specimens had 67.4% Type I fibers and 31.8% Type II fibers, while female specimens had 54.4% Type I fibers and 44.4% Type II fibers. Conclusions Observed fiber type distributions were similar to those reported for other articulatory muscles, but differed slightly from previously reported distributions for normal levator veli palatini. The distributions observed in this study provide a baseline against which to relate fiber type data from the levator veli palatini of cleft palates to the functional status of the velopharyngeal mechanism.

Increase in S6K1 phosphorylation in human skeletal muscle following resistance exercise occurs mainly in type II muscle fibers

2006 ◽  
Vol 290 (6) ◽  
pp. E1245-E1252 ◽  
Author(s):  
René Koopman ◽  
Antoine H. G. Zorenc ◽  
Rudy J. J. Gransier ◽  
David Cameron-Smith ◽  
Luc J. C. van Loon
Keyword(s):  
Skeletal Muscle ◽  
Resistance Exercise ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Initiation Factor ◽  
Exercise Session ◽  
Type I ◽  
Type Ii ◽  
Postexercise Recovery

To investigate the in vivo effects of resistance exercise on translational control in human skeletal muscle, we determined the phosphorylation of AMP-activated kinase (AMPK), eukaryotic initiation factor 4E-binding protein (4E-BP1), p70/p85-S6 protein kinase (S6K1), and ribosomal S6 protein (S6). Furthermore, we investigated whether changes in the phosphorylation of S6K1 are muscle fiber type specific. Eight male subjects performed a single high-intensity resistance exercise session. Muscle biopsies were collected before and immediately after exercise and after 30 and 120 min of postexercise recovery. The phosphorylation statuses of AMPK, 4E-BP1, S6K1, and S6 were determined by Western blotting with phospho-specific and pan antibodies. To determine fiber type-specific changes in the phosphorylation status of S6K1, immunofluorescence microscopy was applied. AMPK phosphorylation was increased approximately threefold immediately after resistance exercise, whereas 4E-BP1 phosphorylation was reduced to 27 ± 6% of preexercise values. Phosphorylation of S6K1 at Thr421/Ser424 was increased 2- to 2.5-fold during recovery but did not induce a significant change in S6 phosphorylation. Phosphorylation of S6K1 was more pronounced in the type II vs. type I muscle fibers. Before exercise, phosphorylated S6K1 was predominantly located in the nuclei. After 2 h of postexercise recovery, phospho-S6K1 was primarily located in the cytosol of type II muscle fibers. We conclude that resistance exercise effectively increases the phosphorylation of S6K1 on Thr421/Ser424, which is not associated with a substantial increase in S6 phosphorylation in a fasted state.

Effects of fiber type and training on beta-adrenoceptor density in human skeletal muscle

1989 ◽  
Vol 257 (5) ◽  
pp. E736-E742 ◽  
Author(s):  
W. H. Martin ◽  
A. R. Coggan ◽  
R. J. Spina ◽  
J. E. Saffitz
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Fiber Type ◽  
Type I ◽  
Type Ii ◽  
Receptor Density ◽  
Beta Receptor ◽  
Type I Fibers ◽  
Total Tissue ◽  
Type Ii Fibers

The density and distribution of beta-adrenergic receptors in type I and II fibers of human gastrocnemius and quadriceps muscles were characterized in ten healthy sedentary subjects and in a subgroup of six subjects before and after 12 wk of endurance exercise training. Total tissue content of beta-receptors was measured in frozen sections of skeletal muscle biopsies incubated with 125I-labeled cyanopindolol in the presence and absence of 10(-5) M L-propranolol. The relative beta-receptor densities of type I and II fibers were delineated autoradiographically. Muscle fiber types were identified in adjacent serial sections by histochemical staining of myofibrillar adenosine-triphosphatase (ATPase) activity. Type I fibers had a threefold greater beta-receptor density than type II fibers of the same muscle [P less than 0.001; type I-to-type II fiber ratio of beta-receptor density was 3.06 +/- 0.43 (SD)]. Exercise training elicited a change in muscle fiber subtype composition (+34% type IIa and -42% type IIb; P less than 0.05 and P = 0.066, respectively), a 40% increase in citrate synthase activity of skeletal muscle (P = 0.01), and a 23% rise in peak oxygen uptake (P less than 0.001). However, no change in total tissue content of beta-receptors was observed after exercise training, even when receptor density was adjusted for preconditioning fiber type composition. Thus beta-receptor density of type I fibers of human skeletal muscle is threefold greater than that of type II fibers. Enhanced capacity for aerobic metabolism after endurance exercise training is not associated with upregulation of total beta-receptor density.

scholarly journals Dissociation between short-term unloading and resistance training effects on skeletal muscle Na+,K+-ATPase, muscle function, and fatigue in humans

2016 ◽  
Vol 121 (5) ◽  
pp. 1074-1086 ◽  
Author(s):  
Ben D. Perry ◽  
Victoria L. Wyckelsma ◽  
Robyn M. Murphy ◽  
Collene H. Steward ◽  
Mitchell Anderson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Muscle Function ◽  
Fiber Type ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Type I ◽  
Type Ii ◽  
Type I Fibers ◽  
Type Ii Fibers

Physical training increases skeletal muscle Na+,K+-ATPase content (NKA) and improves exercise performance, but the effects of inactivity per se on NKA content and isoform abundance in human muscle are unknown. We investigated the effects of 23-day unilateral lower limb suspension (ULLS) and subsequent 4-wk resistance training (RT) on muscle function and NKA in 6 healthy adults, measuring quadriceps muscle peak torque; fatigue and venous [K+] during intense one-legged cycling exercise; and skeletal muscle NKA content ([3H]ouabain binding) and NKA isoform abundances (immunoblotting) in muscle homogenates (α1-3, β1–2) and in single fibers (α1–3, β1). In the unloaded leg after ULLS, quadriceps peak torque and cycling time to fatigue declined by 22 and 23%, respectively, which were restored with RT. Whole muscle NKA content and homogenate NKA α1–3 and β1–2 isoform abundances were unchanged with ULLS or RT. However, in single muscle fibers, NKA α3 in type I (−66%, P = 0.006) and β1 in type II fibers (−40%, P = 0.016) decreased after ULLS, with other NKA isoforms unchanged. After RT, NKA α1 (79%, P = 0.004) and β1 (35%, P = 0.01) increased in type II fibers, while α2 (76%, P = 0.028) and α3 (142%, P = 0.004) increased in type I fibers compared with post-ULLS. Despite considerably impaired muscle function and earlier fatigue onset, muscle NKA content and homogenate α1 and α2 abundances were unchanged, thus being resilient to inactivity induced by ULLS. Nonetheless, fiber type-specific downregulation with inactivity and upregulation with RT of several NKA isoforms indicate complex regulation of muscle NKA expression in humans.

Effect of corticosteroids on diaphragm fatigue, SDH activity, and muscle fiber size

1992 ◽  
Vol 72 (1) ◽  
pp. 293-301 ◽  
Author(s):  
M. I. Lewis ◽  
S. A. Monn ◽  
G. C. Sieck
Keyword(s):  
Fatigue Resistance ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Processing System ◽  
Medial Gastrocnemius ◽  
Type I ◽  
Type Ii ◽  
Cross Sectional ◽  
Type Ii Fibers

The influence of dexamethasone on diaphragm (DIA) fatigue, oxidative capacity, and fiber cross-sectional areas (CSA) was determined in growing hamsters. One group received dexamethasone by daily subcutaneous injection for 21 days (D animals), while pair-weight (P) and free-eating controls (CTL) received saline subcutaneously. Isometric contractile properties of the DIA were determined in vitro by supramaximal direct muscle stimulation in the presence of curare. DIA fatigue resistance was determined through repetitive stimulation at 40 pulses/s for 2 min. A computer-based image-processing system was used to histochemically determine muscle fiber-type proportions, CSA, and succinate dehydrogenase activities. The medial gastrocnemius muscle (MG) was used as a limb muscle control, with histochemical studies being performed on both the superficial (s) and deep/red (r) portions. Dexamethasone markedly attenuated the normal increment in body weight over the 3-wk period. DIA fatigue resistance was significantly reduced in the D compared with CTL and P animals. Dexamethasone had no effect on fiber-type proportions of the DIA or MGr (MGs contained only type II fibers). In the DIA, the CSA of type II fibers was reduced 33% in D and 18.5% in P animals compared with CTL. Although no significant atrophy was noted in the type I DIA fibers of either D or P animals, a trend toward significance was noted in D animals compared with CTL. In the MGs, the CSA of type II fibers was reduced 33% in D and 16.5% in P animals compared with CTL. Significant atrophy of type I and II fibers of the MGr was noted in D animals compared with CTL (33.8 and 35% reductions, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Resistance exercise training promotes fiber type-specific myonuclear adaptations in older adults

2020 ◽  
Vol 128 (4) ◽  
pp. 795-804 ◽  
Author(s):  
Tatiana Moro ◽  
Camille R. Brightwell ◽  
Elena Volpi ◽  
Blake B. Rasmussen ◽  
Christopher S. Fry
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Exercise Training ◽  
Fiber Type ◽  
Type I ◽  
Type Ii ◽  
Resistance Exercise Training ◽  
Myonuclear Domain ◽  
Type I Fibers ◽  
Type Ii Fibers

Aging induces physiological decline in human skeletal muscle function and morphology, including type II fiber atrophy and an increase in type I fiber frequency. Resistance exercise training (RET) is an effective strategy to overcome muscle mass loss and improve strength, with a stronger effect on type II fibers. In the present study, we sought to determine the effect of a 12-wk progressive RET program on the fiber type-specific skeletal muscle hypertrophic response in older adults. Nineteen subjects [10 men and 9 women (71.1 ± 4.3 yr)] were studied before and after the 12-wk program. Immunohistochemical analysis was used to quantify myosin heavy chain (MyHC) isoform expression, cross-sectional area (CSA), satellite cell abundance, myonuclear content, and lipid droplet density. RET induced an increase in MyHC type II fiber frequency and a concomitant decrease in MyHC type I fiber frequency. Mean CSA increased significantly only in MyHC type II fibers (+23.3%, P < 0.05), but myonuclear content increased only in MyHC type I fibers ( P < 0.05), with no change in MyHC type II fibers. Satellite cell content increased ~40% in both fiber types ( P > 0.05). RET induced adaptations to the capillary supply to satellite cells, with the distance between satellite cells and the nearest capillary increasing in type I fibers and decreasing in type II fibers. Both fiber types showed similar decrements in intramuscular lipid density with training ( P < 0.05). Our data provide intriguing evidence for a fiber type-specific response to RET in older adults and suggest flexibility in the myonuclear domain of type II fibers during a hypertrophic stimulus. NEW & NOTEWORTHY In older adults, progressive resistance exercise training (RET) increased skeletal muscle fiber volume and cross-sectional area independently of myonuclear accretion, leading to an expansion of the myonuclear domain. Fiber type-specific analyses illuminated differential adaptation; type II fibers underwent hypertrophy and exhibited myonuclear domain plasticity, whereas myonuclear accretion occurred in type I fibers in the absence of a robust hypertrophic response. RET also augmented satellite cell-capillary interaction and reduced intramyocellular lipid density to improve muscle quality.

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