scholarly journals Skeletal muscle ultrastructure and function in statin-tolerant individuals

2015 ◽  
Vol 53 (2) ◽  
pp. 242-251 ◽  
Author(s):  
Jason L. Rengo ◽  
Damien M. Callahan ◽  
Patrick D. Savage ◽  
Philip A. Ades ◽  
Michael J. Toth
2020 ◽  
Vol 118 (3) ◽  
pp. 258a
Author(s):  
Laszlo Csernoch ◽  
Mónika Gönczi ◽  
Zsolt Ráduly ◽  
László Szabó ◽  
Nóra Dobrosi ◽  
...  

Cell Reports ◽  
2021 ◽  
Vol 34 (9) ◽  
pp. 108796
Author(s):  
Nathaniel D. Steinert ◽  
Gregory K. Potts ◽  
Gary M. Wilson ◽  
Amelia M. Klamen ◽  
Kuan-Hung Lin ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lin Kang ◽  
Pengtao Li ◽  
Danyang Wang ◽  
Taihao Wang ◽  
Dong Hao ◽  
...  

Abstract16S rRNA sequencing of human fecal samples has been tremendously successful in identifying microbiome changes associated with both aging and disease. A number of studies have described microbial alterations corresponding to physical frailty and nursing home residence among aging individuals. A gut-muscle axis through which the microbiome influences skeletal muscle growth/function has been hypothesized. However, the microbiome has yet to be examined in sarcopenia. Here, we collected fecal samples of 60 healthy controls (CON) and 27 sarcopenic (Case)/possibly sarcopenic (preCase) individuals and analyzed the intestinal microbiota using 16S rRNA sequencing. We observed an overall reduction in microbial diversity in Case and preCase samples. The genera Lachnospira, Fusicantenibacter, Roseburia, Eubacterium, and Lachnoclostridium—known butyrate producers—were significantly less abundant in Case and preCase subjects while Lactobacillus was more abundant. Functional pathways underrepresented in Case subjects included numerous transporters and phenylalanine, tyrosine, and tryptophan biosynthesis suggesting that protein processing and nutrient transport may be impaired. In contrast, lipopolysaccharide biosynthesis was overrepresented in Case and PreCase subjects suggesting that sarcopenia is associated with a pro-inflammatory metagenome. These analyses demonstrate structural and functional alterations in the intestinal microbiota that may contribute to loss of skeletal muscle mass and function in sarcopenia.


1979 ◽  
Vol 82 (2) ◽  
pp. 227-234 ◽  
Author(s):  
VIPA BOONNAMSIRI ◽  
J. C. KERMODE ◽  
B. D. THOMPSON

SUMMARY Radio-iodide was administered by prolonged continuous intravenous infusion to rats maintained under iodine-replete conditions and in moderate iodine deficiency. A close approximation to equilibrium labelling was thereby achieved. Labelled iodocompounds extracted from various tissues were analysed by thin-layer chromatography. Moderate iodine deficiency resulted in a slight increase in the ratio of mono-iodotyrosine to di-iodotyrosine in the thyroid. No change in the ratio of tri-iodothyronine (T3) to thyroxine (T4) was found in thyroid, plasma or skeletal muscle. Faecal excretion of T3 declined appreciably relative to that of T4. Under iodine-replete conditions the ratio of thyroidal secretion rates of T3 and T4 was estimated to be more than three times higher than the ratio of these iodocompounds within the thyroid. Heterogeneity of thyroglobulin structure and function may explain these observations.


1996 ◽  
Vol 135 (3) ◽  
pp. 673-687 ◽  
Author(s):  
A J Kreuz ◽  
A Simcox ◽  
D Maughan

Drosophila indirect flight muscle (IFM) contains two different types of tropomyosin: a standard 284-amino acid muscle tropomyosin, Ifm-TmI, encoded by the TmI gene, and two > 400 amino acid tropomyosins, TnH-33 and TnH-34, encoded by TmII. The two IFM-specific TnH isoforms are unique tropomyosins with a COOH-terminal extension of approximately 200 residues which is hydrophobic and rich in prolines. Previous analysis of a hypomorphic TmI mutant, Ifm(3)3, demonstrated that Ifm-TmI is necessary for proper myofibrillar assembly, but no null TmI mutant or TmII mutant which affects the TnH isoforms have been reported. In the current report, we show that four flightless mutants (Warmke et al., 1989) are alleles of TmI, and characterize a deficiency which deletes both TmI and TmII. We find that haploidy of TmI causes myofibrillar disruptions and flightless behavior, but that haploidy of TmII causes neither. Single fiber mechanics demonstrates that power output is much lower in the TmI haploid line (32% of wild-type) than in the TmII haploid line (73% of wild-type). In myofibers nearly depleted of Ifm-TmI, net power output is virtually abolished (< 1% of wild-type) despite the presence of an organized fibrillar core (approximately 20% of wild-type). The results suggest Ifm-TmI (the standard tropomyosin) plays a key role in fiber structure, power production, and flight, with reduced Ifm-TmI expression producing corresponding changes of IFM structure and function. In contrast, reduced expression of the TnH isoforms has an unexpectedly mild effect on IFM structure and function.


1980 ◽  
Vol 8 (1) ◽  
pp. 87-107 ◽  
Author(s):  
Marion I. Barnhart ◽  
Tae H. Kim ◽  
Bruce L. Evatt ◽  
Abdelsalam H. Ragab ◽  
Victor K. Lui ◽  
...  

2006 ◽  
Vol 570 (3) ◽  
pp. 611-627 ◽  
Author(s):  
Giuseppe D'Antona ◽  
Francesca Lanfranconi ◽  
Maria Antonietta Pellegrino ◽  
Lorenza Brocca ◽  
Raffaella Adami ◽  
...  

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Kunihiro Sakuma ◽  
Akihiko Yamaguchi

This paper summarizes the various effects of neurotrophins in skeletal muscle and how these proteins act as potential regulators of the maintenance, function, and regeneration of skeletal muscle fibers. Increasing evidence suggests that this family of neurotrophic factors influence not only the survival and function of innervating motoneurons but also the development and differentiation of myoblasts and muscle fibers. Muscle contractions (e.g., exercise) produce BDNF mRNA and protein in skeletal muscle, and the BDNF seems to play a role in enhancing glucose metabolism and may act for myokine to improve various brain disorders (e.g., Alzheimer's disease and major depression). In adults with neuromuscular disorders, variations in neurotrophin expression are found, and the role of neurotrophins under such conditions is beginning to be elucidated. This paper provides a basis for a better understanding of the role of these factors under such pathological conditions and for treatment of human neuromuscular disease.


1994 ◽  
Vol 14 (12) ◽  
pp. 8051-8057
Author(s):  
X Zhu ◽  
J E Yeadon ◽  
S J Burden

Although most skeletal muscle genes are expressed at similar levels in electrically active, innervated muscle and in electrically inactive, denervated muscle, a small number of genes, including those encoding the acetylcholine receptor, N-CAM, and myogenin, are expressed at significantly higher levels in denervated than in innervated muscle. The mechanisms that mediate electrical activity-dependent gene regulation are not understood, but these mechanisms are likely to be responsible, at least in part, for the changes in muscle structure and function that accompany a decrease in myofiber electrical activity. To understand how muscle activity regulates muscle structure and function, we used a subtractive-hybridization and cloning strategy to identify and isolate genes that are expressed preferentially in innervated or denervated muscle. One of the genes which we found to be regulated by electrical activity is the recently discovered acute myeloid leukemia 1 (AML1) gene. Disruption and translocation of the human AML1 gene are responsible for a form of acute myeloid leukemia. AML1 is a DNA-binding protein, but its normal function is not known and its expression and regulation in skeletal muscle were not previously appreciated. Because of its potential role as a transcriptional mediator of electrical activity, we characterized expression of the AML1 gene in innervated, denervated, and developing skeletal muscle. We show that AML1 is expressed at low levels in innervated skeletal muscle and at 50- to 100-fold-higher levels in denervated muscle. Four AML1 transcripts are expressed in denervated muscle, and the abundance of each transcript increases after denervation. We transfected C2 muscle cells with an expression vector encoding AML1, tagged with an epitope from hemagglutinin, and we show that AML1 is a nuclear protein in muscle. AML1 dimerizes with core-binding factor beta (CBF beta), and we show that CGF beta is expressed at high levels in both innervated and denervated skeletal muscle. PEBP2 alpha, which is structurally related to AML1 and which also dimerizes with CBF beta, is expressed at low levels in skeletal muscle and is up-regulated only weakly by denervation. These results are consistent with the idea that AML1 may have a role in regulating gene expression in skeletal muscle.


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