Muscle fiber formation and fiber hypertrophy during the onset of stretch-overload

1990 ◽  
Vol 259 (1) ◽  
pp. C92-C102 ◽  
Author(s):  
S. E. Alway ◽  
W. J. Gonyea ◽  
M. E. Davis
Keyword(s):  
Muscle Mass ◽  
Cross Sectional Area ◽  
Fiber Formation ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fiber Splitting ◽  
Anterior Latissimus Dorsi ◽  
Fiber Number ◽  
Nitric Acid Digestion ◽  
Animal Control

The contributions of fiber hypertrophy and new fiber formation to the onset of stretch-induced muscle enlargement were evaluated in the anterior latissimus dorsi (ALD) of adult Japanese quails, because it was not known whether the mechanisms which initiate new fiber formation were dependent on first achieving significant fiber hypertrophy. A weight corresponding to 10% of the bird's body mass was attached to one wing, and eight birds were killed after each day during the first week of stretch. Muscle mass was significantly increased after 48 h of stretch; however, the elevation in nonmuscle tissue accounted for this increase. Muscle mass corrected for non-muscle tissue was significantly greater than the intra-animal control by the fourth day of stretch. Mean fiber cross-sectional area did not change during days 0-6, but cross-sectional area was 30.0 +/- 17.2% greater than the intra-animal control areas at day 7. Fiber number determined after nitric acid digestion of connective tissue was 27.1 +/- 5.8% greater than the intra-animal control at days 5-7 of stretch, but the number of fibers in the control muscles at days 5 and 6 were lower than at day 0. Thus new fiber formation was not preceded by significant fiber hypertrophy. These results fail to support a mechanism for new fiber formation which involves fiber splitting from hypertrophied myofibers during the first week of stretch.

Regionalized adaptations and muscle fiber proliferation in stretch-induced enlargement

1989 ◽  
Vol 66 (2) ◽  
pp. 771-781 ◽  
Author(s):  
S. E. Alway ◽  
P. K. Winchester ◽  
M. E. Davis ◽  
W. J. Gonyea
Keyword(s):  
Muscle Fiber ◽  
Latissimus Dorsi ◽  
Volume Density ◽  
Cross Sectional ◽  
Adult Skeletal Muscle ◽  
Relative Contribution ◽  
Anterior Latissimus Dorsi ◽  
Fiber Number ◽  
Nitric Acid Digestion ◽  
Alpha Type

The relative contribution of increases in fiber area to stretch-induced muscle enlargement was evaluated in the slow tonic fibers of the anterior latissimus dorsi of adult Japanese quails. A weight corresponding to 10% of the bird's body mass was attached to one wing. Thirty days of stretch in 34 birds averaged 171.8 +/- 13.5% increase in muscle mass and 23.5 +/- 0.8% increase in muscle fiber length. The volume density of noncontractile tissue increased in middle and distal regions of stretch-enlarged muscles. Mean fiber cross-sectional area increased 56.7 +/- 12.3% in the midregion of stretched muscles. Further analysis indicated slow beta-fiber hypertrophy occurred in proximal, middle, and distal regions; however, fast alpha-type fiber hypertrophy was limited to middle regions of stretched muscles. Stretched muscles had a significant increase in the frequency of slow beta-fibers that were less than 500 microns 2 in all regions and fast alpha-type fibers in middle and distal regions. Total fiber number was determined after nitric acid digestion of connective tissue in 10 birds. Fiber number increased 51.8 +/- 19.4% in stretched muscle. These results are the first to clearly show that muscle fiber proliferation contributes substantially to adult skeletal muscle stretch-induced enlargement, although we do not know whether the responses of the slow tonic anterior latissimus dorsi might be similar or different from mammalian twitch muscle.

scholarly journals The Nonlinear Relationship Between Psoas Cross-sectional Area and BMI: A New Observation and Its Insights into Diabetes Remission After Roux-en-Y Gastric Bypass

2021 ◽  
Author(s):  
Shaobo Li ◽  
Haoyong Yu ◽  
Pin Zhang ◽  
Yinfang Tu ◽  
Yunfeng Xiao ◽  
...  
Keyword(s):  
Gastric Bypass ◽  
Linear Relationship ◽  
Muscle Mass ◽  
Diabetes Remission ◽  
Cross Sectional Area ◽  
Fat Free Mass ◽  
Sectional Area ◽  
Cross Sectional ◽  
Non Linear ◽  
Design And Methods

OBJECTIVE <p>To<a> explore the potential relevance of muscle mass as a variable contributor to body mass index (BMI) on BMI limitations in predicting diabetes remission (DR) after Roux-en-Y gastric bypass (RYGB). </a></p> <p> </p> <p>RESEARCH DESIGN AND METHODS</p> <p>We evaluated the relationship between muscle mass and BMI in 501 patients with type 2 diabetes mellitus and overweight or obesity. Of which <a>186 patients who underwent R</a>YGB were <a>studied to determine the role of baseline muscle mass </a><a>and BMI </a>in predicting DR. Muscle mass was assessed by estimated fat-free mass index (eFFMI) and psoas cross-sectional area (CSA).</p> <p> </p> <p>RESULTS</p> <p>A non-linear relationship existed between psoas CSA and BMI, whereas psoas CSA showed a highly positive correlation with <a>eFFMI</a>. Baseline psoas CSA and eFFMI were better than BMI for predicting 1- and 5-year DR. </p> <p> </p> <p>CONCLUSIONS</p> <p><a>The </a><a>non-linear relationship between</a> muscle mass and BMI may <a>partially contribute to </a><a>BMI limitations in predicting DR</a> after RYGB. </p>

Hypertrophy and proliferation of skeletal muscle fibers from aged quail

1995 ◽  
Vol 78 (1) ◽  
pp. 293-299 ◽  
Author(s):  
J. A. Carson ◽  
M. Yamaguchi ◽  
S. E. Alway
Keyword(s):  
Muscle Mass ◽  
Fiber Type ◽  
Right Wing ◽  
Left Wing ◽  
Cross Sectional ◽  
Anterior Latissimus Dorsi ◽  
Fiber Number ◽  
Fiber Type Distribution ◽  
Distribution Shifts ◽  
The Right

The purpose of this study was to determined whether fibers in the anterior latissimus dorsi (ALD) muscle from aged Japanese quail have decreased hypertrophic or proliferative responses to 30 days of stretch overload compared with fibers from adult birds. Two groups of quail were studied, 12-wk-old quail (adult; n = 16) and 90-wk-old quail (aged; n = 16). The left wing of each bird was overloaded with a weight corresponding to 10% of the bird's body weight, and the right wing served as the intra-animal control. Quails were killed after 30 days of stretch overload. Total fiber number was quantified by counting all the fibers in a transverse section from the midbelly of the ALD muscle. ALD muscles in aged quails retained the capacity to increase their muscle mass (145%), total fiber number (49%), and fiber cross-sectional area (54%) in response to stretch overload. The ALD muscle in aged quail had a significantly lower increase in muscle mass (33%) and mass corrected for nonmuscle tissue (36%) compared with the ALD from young adult birds. Age had no effect on fiber type distribution shifts with stretch. These results suggest that although muscles in old birds have a substantial ability to adapt to enlarge, stretch-induced hypertrophy is attenuated in muscles from old quail.

scholarly journals Inorganic Arsenic Exposure Decreases Muscle Mass and Enhances Denervation-Induced Muscle Atrophy in Mice

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3057
Author(s):  
Chang-Mu Chen ◽  
Min-Ni Chung ◽  
Chen-Yuan Chiu ◽  
Shing-Hwa Liu ◽  
Kuo-Cheng Lan
Keyword(s):  
Drinking Water ◽  
Protein Expression ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Arsenic Exposure ◽  
Inorganic Arsenic ◽  
Cross Sectional Area ◽  
Muscle Endurance ◽  
Sectional Area ◽  
Cross Sectional

Arsenic is a toxic metalloid. Infants with a low birth-weight have been observed in areas with high-level arsenic in drinking water ranging from 463 to 1025 μg/L. A distal muscular atrophy side effect has been observed in acute promyelocytic leukemia patients treated with arsenic trioxide (As2O3) for therapy. The potential of As2O3 on muscle atrophy remains to be clarified. In this study, the myoatrophic effect of arsenic was evaluated in normal mice and sciatic nerve denervated mice exposed with or without As2O3 (0.05 and 0.5 ppm) in drinking water for 4 weeks. We found that both 0.05 and 0.5 ppm As2O3 increased the fasting plasma glucose level; but only 0.5 ppm arsenic exposure significantly decreased muscle mass, muscle endurance, and cross-sectional area of muscle fibers, and increased muscle Atrogin-1 protein expression in the normal mice. Both 0.05 and 0.5 ppm As2O3 also significantly enhanced the inhibitory effects on muscle endurance, muscle mass, and cross-sectional area of muscle fibers, and increased the effect on muscle Atrogin-1 protein expression in the denervated mice. These in vivo results suggest that inorganic arsenic at doses relevant to humans may possess myoatrophic potential.

Intra- and inter-rater reliability in the cross-sectional area of feline lumbar epaxial musculature evaluated via abdominal CT scan

2019 ◽  
Vol 22 (8) ◽  
pp. 721-728
Author(s):  
Laura H Rayhel ◽  
Jessica M Quimby ◽  
Eric M Green ◽  
Valerie J Parker ◽  
Shasha Bai
Keyword(s):  
Ct Scan ◽  
Muscle Mass ◽  
Ct Images ◽  
Cross Sectional Area ◽  
Area Measurement ◽  
Thoracic Vertebrae ◽  
Sectional Area ◽  
Cross Sectional ◽  
Rater Reliability ◽  
Epaxial Muscle

Objectives The aim of this study was to evaluate the intra- and inter-rater reliability of epaxial muscle cross-sectional area measurement on feline CT images and to determine the relationship between normalized epaxial muscle area (EMA) and subjective muscle condition score (MCS). Methods Feline transverse CT images including the junction of the 13th thoracic vertebrae/13th rib head were retrospectively reviewed. Right and left epaxial muscle circumference and vertebral body height were measured and an average normalized EMA (ratio of epaxial area:vertebral height) was calculated for each image. Measurements were performed by three individuals blinded to the clinical data and were repeated 1 month later. Intra- and inter-rater reliability of EMA was assessed with concordance correlation coefficient (CCC), and Bland–Altman analysis was performed to assess bias and limits of agreement (LoA) between and within observers at different time points. In cats for which MCS data were available, EMA was compared between differing MCSs via the Kruskal–Wallis test, with Bonferroni-corrected Wilcoxon rank-sum post-hoc analysis. Results In total, 101 CT scans met the inclusion criteria for reliability analysis, 29 of which had muscle condition information available for analysis. Intra-rater EMA CCC ranged from 0.84 to 0.99 with minimal bias (range –0.16 to 0.08) and narrow LoA. Inter-rater EMA CCC ranged from 0.87 to 0.94, bias was larger (range –0.46 to 0.66) and LoA were wider when assessed between observers. Median EMA was significantly lower in cats with severe muscle atrophy (2.76, range 1.28–3.96) than in all other MCS groups ( P <0.0001 for all comparisons). Conclusions and relevance Measurement of EMA on CT showed strong intra-rater reliability, and median EMA measurements were significantly lower in cats with severe muscle wasting, as assessed on physical examination. Further studies correlating EMA to lean muscle mass in cats are needed to determine whether this method may be useful to quantify muscle mass in patients undergoing a CT scan.

scholarly journals The Effects of Calcium-β-Hydroxy-β-Methylbutyrate on Aging-Associated Apoptotic Signaling and Muscle Mass and Function in Unloaded but Nonatrophied Extensor Digitorum Longus Muscles of Aged Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Brian T. Bennett ◽  
Junaith S. Mohamed ◽  
Stephen E. Alway
Keyword(s):  
Muscle Mass ◽  
Satellite Cells ◽  
Muscle Function ◽  
Extensor Digitorum Longus ◽  
Cross Sectional Area ◽  
Extensor Digitorum ◽  
Aged Rats ◽  
Sectional Area ◽  
Cross Sectional ◽  
Apoptotic Signaling

Beta-hydroxy-beta-methylbutyrate (HMB), a naturally occurring leucine metabolite, has been shown to attenuate plantar flexor muscle loss and increase myogenic stem cell activation during reloading after a period of significant muscle wasting by disuse in old rodents. However, it was less clear if HMB would alter dorsiflexor muscle response to unloading or reloading when there was no significant atrophy that was induced by unloading. In this study, we tested if calcium HMB (Ca-HMB) would improve muscle function and alter apoptotic signaling in the extensor digitorum longus (EDL) of aged animals that were unloaded but did not undergo atrophy. The EDL muscle was unloaded for 14 days by hindlimb suspension (HS) in aged (34-36 mo.) male Fisher 344×Brown Norway rats. The rats were removed from HS and allowed normal cage ambulation for 14 days of reloading (R). Throughout the study, the rats were gavaged daily with 170 mg of Ca-HMB or water 7 days prior to HS, then throughout 14 days of HS and 14 days of recovery after removing HS. The animals’ body weights were significantly reduced by ~18% after 14 days of HS and continued to decline by ~22% during R as compared to control conditions; however, despite unloading, EDL did not atrophy by HS, nor did it increase in mass after R. No changes were observed in EDL twitch contraction time, force production, fatigue resistance, fiber cross-sectional area, or markers of nuclear apoptosis (myonuclei + satellite cells) after HS or R. While HS and R increased the proapoptotic Bax protein abundance, BCL-2 abundance was also increased as was the frequency of TUNEL-positive myonuclei and satellite cells, yet muscle mass and fiber cross-sectional area did not change and Ca-HMB treatment had no effect reducing apoptotic signaling. These data indicate that (i) increased apoptotic signaling preceded muscle atrophy or occurred without significant EDL atrophy and (ii) that Ca-HMB treatment did not improve EDL signaling, muscle mass, or muscle function in aged rats, when HS and R did not impact mass or function.

Effects of 6 months of abiraterone acetate (AA) on muscle and adipose mass in men with metastatic castration-resistant prostate cancer (mCRPC).

2012 ◽  
Vol 30 (5_suppl) ◽  
pp. 222-222 ◽  
Author(s):  
Samuel Craig Brondfield ◽  
Vivian K. Weinberg ◽  
Kathryn M. Koepfgen ◽  
Arturo Molina ◽  
Charles J. Ryan ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Muscle Wasting ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Adipose Mass

222 Background: AA, an inhibitor of androgen biosynthesis, has been shown to prolong overall survival in patients with mCRPC who have previously been treated with chemotherapy. Androgen deprivation therapy (ADT) has been shown to result in muscle wasting in prostate cancer pts. The effects of AA on progression of muscle and fat wasting have not been characterized. We evaluated whether 6 months of AA therapy altered total skeletal muscle mass or adipose mass. Methods: 10 sequential pts who responded to AA therapy for at least 6 months and had available computed tomography (CT) scans were retrospectively selected from the phase I-II COU-AA-002 study. CT image analysis was used to quantify change from baseline in total skeletal muscle and adipose tissue after 6 months of AA treatment. Skeletal muscle and adipose tissue cross-sectional area were calculated at the L3 level using Slice-O-Matic software V4.3. Previously published regression models were used to estimate fat-free mass, fat mass and skeletal muscle mass. Paired t-tests were performed to determine the change in measurements. Results: At baseline, 7 of 10 pts were overweight or obese (body mass index [BMI] > 25 kg/m2), and none were underweight. Advanced muscle wasting (sarcopenia, previously defined as the ratio of skeletal muscle cross-sectional area at L3 level to height < 52.4 cm2/m2) was present at baseline and 6 months in 9 of 10 pts. Over 6 months of AA treatment, pts lost an average of 1.9 kg ± 1.9 kg (p = 0.13). Mean changes (kg) (±standard deviation) in total skeletal muscle mass (−0.80 ± 1.71, p = 0.18) and total non-adipose mass (−1.44 ± 3.09, p = 0.17) were not significant. A significant decrease in total adipose mass (−0.61 ± 0.84, p = 0.048) was observed. Conclusions: Sarcopenia is prevalent in pts with mCRPC. AA was not related to significantly worsening sarcopenia or overall weight loss during the first 6 months of treatment; however, this may reflect a relatively short duration of therapy and/or small sample size. A significant loss of adipose tissue was observed, which is unexpected given the known effects of ADT, which increases adipose mass. Evaluation of additional AA treated patients is ongoing.

scholarly journals Comparison of M.Semitendinosus Morphometry and Structure in Gilts and Barrows at Market Age

2016 ◽  
Vol 66 (1) ◽  
pp. 132-137
Author(s):  
Ivana Božičković ◽  
Duško Vitorović ◽  
Miloš Blagojević ◽  
Ivana Nešić ◽  
Slavoljub Jović ◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Histological Structure ◽  
Fiber Types ◽  
Sectional Area ◽  
Morphometric Characteristics ◽  
Cross Sectional ◽  
Fiber Number ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Very High

AbstractThe aim of this paper was to investigate the differences in morphometric characteristics and histological structure of m. semitendinosus, between gilts and barrows of German Landrace breed at the end of the fattening period. Morphometric characteristics (weight, length, diameter and cross sectional area) of m. semitendinosus were not significantly different, while gender as a factor influenced the histological properties of this muscle. A very high statistical difference (p<0.01) in the total number of muscle fibers in m. semitendinosus was determined, with gilts having a higher total fiber number. The cross sectional area of fast twitch oxidative (FTO) fibers was significantly higher (p<0.05) in barrows. Gender did not affect the distribution of different fiber types: in both gender, the most present fiber types (48-52 %) were fast twitch glycolitic (FTG), FTO fibers represented 27-30 % of the total fiber number, while slow twitch oxidative fibers (STO) were the least represented (≈ 20 %).

scholarly journals Heart size and mean muscle fibre cross-sectional area related to birth weight in pigs

2008 ◽  
Vol 16 (3) ◽  
pp. 259 ◽  
Author(s):  
M. RUUSUNEN ◽  
E. PUOLANNE ◽  
K. PARTANEN
Keyword(s):  
Birth Weight ◽  
Growth Performance ◽  
Muscle Mass ◽  
Carcass Composition ◽  
Cross Sectional Area ◽  
Heart Weight ◽  
Longissimus Dorsi ◽  
Muscle Fibres ◽  
Sectional Area ◽  
Cross Sectional

One of the aims in domestic pig breeding has been to increase the size of litters resulting in variation in birth weight of piglets. Pig breeding has also resulted in increased body muscle mass. Muscles with the same size can consist either of large number of thin muscle fibres or small number of thick muscle fibres. Larger body muscle content means that in living animal the heart must pump blood to larger muscle mass than earlier. Our interest in this study was to investigate the relationship between the pig’s birth weight and (i) growth performance and carcass composition, (ii) the size of organs, and (iii) the mean muscle fibre cross-sectional area at slaughter. The study consisted of twenty pigs slaughtered at the age of 165±2 days. The day after the slaughter, the carcass composition was determined by dissecting the chilled carcass into lean, fat, bones, and skin and organs were weighed. The average cross sectional area of muscle fibres was determined from three fast-twitch muscles longissimus dorsi, semimembranosus, gluteus superficialis, and two slow-twitch muscles infraspinatus and masseter. The birth weight of pigs ranged from 0.9 to 2.2 kg. We found no clear relationships between the birth weight and the pig’s growth performance from birth to slaughter. When the birth weight increased the heart weight at slaughter increased as well (P < 0.01). The heart weight was higher in those pigs with high carcass weight (P < 0.05) and with the high weight of total muscle mass in the carcass (P < 0.001). The cross sectional area of muscle fibres in M. longissimus dorsi (P < 0.05), M. semimembranosus (P < 0.10), and M. gluteus superficialis (P < 0.05) was larger in those pigs with low birth weight compared to those found in pigs with high birth weight.;

scholarly journals Passive repetitive stretching increases skeletal muscle mass and myofiber cross-sectional area in senescence-accelerated model mouse

2021 ◽  
Author(s):  
Yumin Wang ◽  
Satoshi Ikeda ◽  
Katsunori Ikoma
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
Signaling Pathways ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Gastrocnemius Muscle ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Passive Stretching

Abstract Mechanical stimulation has benefits for muscle mass and function. Passive stretching is widely performed in clinical rehabilitation medicine. However, the hypertrophic effects of passive repetitive stretching on senescent skeletal muscles against muscle atrophy remain unknown. We used senescence-accelerated model SAM-P8 mice. The gastrocnemius muscle was passively repetitive stretched by manual ankle dorsiflexion for 15 min, 5 days a week for 2 weeks under deep anesthesia. We examined the effects of passive stretching on muscle mass, myofiber cross-sectional area, muscle fiber type and composition, satellite cell content, mRNA expression of the signaling pathways involved in muscle protein synthesis, muscle-specific ubiquitin ligases, and myogenic regulatory factors. The gastrocnemius muscle weight of the stretched side increased compared with that of the unstretched side. In addition to the increase in muscle mass, muscle fiber cross-sectional area of the stretched side was greater than that of the unstretched side. Passive repetitive stretching significantly increased the mRNA expression level of Akt, p70S6K, 4E-BP1, Myf5, myogenin, MuRF1. Passive repetitive stretching promoted skeletal muscle mass and myofiber cross-sectional area in SAM-P8 mice. These hypertrophic observations are attributable to the stretch-activated signaling pathways involved in protein turnover. These findings are applicable to clinical muscle strengthening and sarcopenia prevention.

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