Chronic heart failure-induced skeletal muscle atrophy, necrosis, and changes in myogenic regulatiory factors

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Martinez, Paula F. ; Okoshi, Katashi ; Zornoff, Leonardo A. M. ; Carvalho, Robson F. ; Oliveira Junior, Silvio A. ; Lima, Aline R. R. ; Campos, Dijon H. S. ; Damatto, Ricardo L. ; Padovani, Carlos R. ; Nogueira, Celia R. ; Pai-Silva, Maeli Dai ; Okoshi, Marina P.

• Tipo de documento: Artigo Científico
• Fonte: MEDICAL SCIENCE MONITOR; v. 16, n. 12, p. 10-pg., 2010-12-01.

Resumo

Background: Although intrinsic skeletal muscle abnormalities can influence exercise intolerance during heart failure (HF), the factors responsible for muscle changes have not been elucidated. In this study we evaluated the expression of myogenic regulatory factors (MRF), myosin heavy chain (MyHC) isoforms, and fiber trophism in the soleus muscle of rats with myocardial infarction-induced heart failure. Method/Results: Six months after surgery, 2 groups of rats were studied: sham, and infarcted rats with HF (MI/HF+, MI size: 41.1 +/- 6.3% of total left ventricular area). In the infarcted group, microscopic evaluation revealed scattered foci of fiber necrosis in combination with inflammatory cells, phagocytosis, and increased fibrous tissue. The frequency of necrotic fibers was significantly higher in the MI/HF+ group than in the sham. The MI/HF+ group had atrophy of type I, IC/IIC, and HA fibers compared to the sham group (P<0.05). MyoD gene expression was higher in the MI/HF+ group (sham: 1.00 +/- 0.49; MI/HF+: 2.53 +/- 0.71 arbitrary units; P<0.001). Myogenin and MRF4 gene expression was similar in both groups. Myogenin protein levels were reduced in the MI/HF+ group (sham: 1.00 +/- 0.21; MI/HF+: 0.74 +/- 0.21 arbitrary units; P=0.026). MyoD and MRF4 protein levels, as well as the MyHC distribution, were not different between groups. The MI/HF+ group had higher TNF-alpha and IL-6 serum concentrations than the sham group. Conclusions: Heart failure-induced skeletal muscle atrophy is combined with fiber necrosis, increased MyoD gene expression and decreased myogenin protein levels. (AU)

• Processo FAPESP: 05/58294-3 - Expressao de fatores de regulacao miogenica e composicao das miosinas no musculo esqueletico periferico de ratos com insuficiencia cardiaca cronica.
• Beneficiário: Paula Felippe Martinez
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 05/60767-7 - Expressão dos fatores de regulação miogênica e composição das miosinas no músculo esquelético periférico de ratos com insuficiência cardíaca crônica
• Beneficiário: Marina Politi Okoshi
• Modalidade de apoio: Auxílio à Pesquisa - Regular