Skeletal Muscle
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2021 ◽  
Vol 22 (1) ◽  
Kosei Yamaguchi ◽  
Mineaki Kitamura ◽  
Takahiro Takazono ◽  
Shuntaro Sato ◽  
Kazuko Yamamoto ◽  

Abstract Background Although muscle mass loss and pneumonia are common and crucial issues in hemodialysis (HD) patients, few reports have focused on their association, which remains unclear. This study assessed the association between skeletal muscle mass and the incidence of pneumonia in HD patients using the psoas muscle index (PMI). Methods This retrospective study included 330 patients on HD who were treated at a single center between July 2011 and June 2012. The observation period was between July 2011 and June 2021. Demographic, clinical, and HD data were collected, and the associations between PMI and hospitalization due to bacterial pneumonia were evaluated using Cox proportional hazards models adjusted for patients’ background data. Additionally, the correlation between patient characteristics and PMI was evaluated using multivariable linear regression. Results Among 330 patients (mean age, 67.3 ± 13.3; 56.7% male; median dialysis vintage 58 months, (interquartile range [IQR] 23–124), 79 were hospitalized for pneumonia during the observation period (median observation period was 4.5 years [IQR 2.0–9.1]). The multivariable Cox proportional analysis, which was adjusted for age, sex, dialysis vintage, diabetes mellitus, and stroke history and considered death as a competing risk, indicated that decreased PMI/(standard deviation) was closely associated with the development of pneumonia (hazard ratio: 0.67, 95% confidence interval: 0.47–0.95, p = 0.03). Conclusions Skeletal muscle mass was associated with the development of pneumonia in patients on HD and could be a useful marker for the risk of pneumonia.

2021 ◽  
Vol 26 (1) ◽  
Kenji Endo ◽  
Jun Matsubayashi ◽  
Yasunobu Sawaji ◽  
Kazuma Murata ◽  
Takamitsu Konishi ◽  

Abstract Background To date, the histopathologic characteristics of dropped head syndrome (DHS) have not been reported sufficiently. The present study investigates the histopathology of biopsy specimens from the cervical paravertebral region in patients with DHS. Methods Histopathological parameters were evaluated in biopsy specimens of the cervical paravertebral soft tissue from 15 patients with DHS. Results Among the 15 cases of DHS examined, skeletal muscle was identified in 7 cases, all of which showed necrosis, microvessel proliferation and atrophy. The ligament was identified in 12 cases, 8 of which showed degeneration. The lag time between the onset of symptoms and the performance of a biopsy in all 8 cases, which showed degeneration was over 3 months. Microvessel proliferation in the ligament was observed in 1 of the 4 cases, in which the lag time between the onset of symptoms and the performance of a biopsy was less than 3 months (acute or subacute phase), and in 7 of the 8 cases, in which the lag time between the symptoms and the performance of a biopsy was over 3 months (chronic phase). Chronic inflammation in the ligament was identified in 1 of the 12 cases. Conclusions The identification of necrosis, microvessel proliferation, and atrophy in the skeletal muscle of patients with DHS and the presence of ligament degeneration and microvessel proliferation in the chronic but not acute or subacute phases may suggest that persistent skeletal muscle damage of the cervical paravertebral region causes subsequent ligament damage in patients with DHS.

2021 ◽  
Vol 12 (1) ◽  
Dominik Laubscher ◽  
Berkley E. Gryder ◽  
Benjamin D. Sunkel ◽  
Thorkell Andresson ◽  
Marco Wachtel ◽  

AbstractRhabdomyosarcoma (RMS) is a pediatric malignancy of skeletal muscle lineage. The aggressive alveolar subtype is characterized by t(2;13) or t(1;13) translocations encoding for PAX3- or PAX7-FOXO1 chimeric transcription factors, respectively, and are referred to as fusion positive RMS (FP-RMS). The fusion gene alters the myogenic program and maintains the proliferative state while blocking terminal differentiation. Here, we investigated the contributions of chromatin regulatory complexes to FP-RMS tumor maintenance. We define the mSWI/SNF functional repertoire in FP-RMS. We find that SMARCA4 (encoding BRG1) is overexpressed in this malignancy compared to skeletal muscle and is essential for cell proliferation. Proteomic studies suggest proximity between PAX3-FOXO1 and BAF complexes, which is further supported by genome-wide binding profiles revealing enhancer colocalization of BAF with core regulatory transcription factors. Further, mSWI/SNF complexes localize to sites of de novo histone acetylation. Phenotypically, interference with mSWI/SNF complex function induces transcriptional activation of the skeletal muscle differentiation program associated with MYCN enhancer invasion at myogenic target genes, which is recapitulated by BRG1 targeting compounds. We conclude that inhibition of BRG1 overcomes the differentiation blockade of FP-RMS cells and may provide a therapeutic strategy for this lethal childhood tumor.

2021 ◽  
Vol 11 (1) ◽  
Amritpal S. Bhullar ◽  
Irma Magaly Rivas-Serna ◽  
Ana Anoveros-Barrera ◽  
Abha Dunichand-Hoedl ◽  
David Bigam ◽  

AbstractEmerging studies are reporting associations between skeletal muscle abnormalities and survival in cancer patients. Cancer prognosis is associated with depletion of essential fatty acids in erythrocytes and plasma in humans. However the relationship between skeletal muscle membrane fatty acid composition and survival is unknown. This study investigates the relationship between fatty acid content of phospholipids in skeletal muscle and survival in cancer patients. Rectus abdominis biopsies were collected during cancer surgery from 35 patients diagnosed with cancer. Thin-layer and gas chromatography were used for quantification of phospholipid fatty acids. Cutpoints for survival were defined using optimal stratification. Median survival was between 450 and 500 days when patients had arachidonic acid (AA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in muscle phospholipid below the cut-point compared to 720–800 days for patients above. Cox regression analysis revealed that low amounts of AA, EPA and DHA are risk factors for death. The risk of death remained significant for AA [HR 3.5 (1.11–10.87), p = 0.03], EPA [HR 3.92 (1.1–14.0), p = 0.04] and DHA [HR 4.08 (1.1–14.6), p = 0.03] when adjusted for sex. Lower amounts of essential fatty acids in skeletal muscle membrane is a predictor of survival in cancer patients. These results warrant investigation to restore bioactive fatty acids in people with cancer.

2021 ◽  
pp. 1-3
Koichi Takamizawa ◽  
Ki-Sung Kim ◽  
Hideaki Ueda

Abstract Emery-Dreifuss muscular dystrophy is a slowly progressive skeletal muscle and joint disorder associated with cardiac complications. Dilated cardiomyopathy was the initial manifestation of Emery-Dreifuss muscular dystrophy in an 8-year-old girl. Despite normal muscle and myocardial biopsies, genetic testing revealed LMNA mutations. As Emery-Dreifuss muscular dystrophy is associated with minimal skeletal muscle weakness, cardiac complications can facilitate its diagnosis.

Xiaoling Liu ◽  
Er Zu ◽  
Xinyu Chang ◽  
Xiaowei Ma ◽  
Ziqi Wang ◽  

Skeletal muscle regeneration requires extracellular matrix (ECM) remodeling, including an acute and transient breakdown of collagen that produces gelatin. Although the physiological function of this process is unclear, it has inspired us to apply gelatin to injured skeletal muscle for a potential pro-regenerative effect. Here we elaborate on a bi-phasic effect of gelatin in skeletal muscle regeneration, mediated by hormetic effects of reactive oxygen species (ROS). Low-dose gelatin stimulates ROS production from NADPH oxidase 2 (NOX2) and simultaneously upregulates antioxidant system for cellular defense, reminiscent of the adaptive compensatory process during mild stress. This response triggers the release of myokine IL-6 that stimulates myogenesis and facilitates muscle regeneration. By contrast, high-dose gelatin stimulates ROS overproduction from NOX2 and mitochondrial chain complex, and ROS accumulation by suppressing antioxidant system, triggering release of TNFα, which inhibits myogenesis and regeneration. Our results have revealed a bi-phasic role of gelatin in regulating skeletal muscle repair mediated by intracellular ROS, antioxidant system, and cytokines (IL-6 and TNFα) signaling.

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