Skeletal muscle alterations in chronic heart failure: differential effects on quadriceps and diaphragm

Chronic heart failure induced divergent antioxidative and metabolic but similar catabolic responses between the diaphragm and quadriceps. Despite the quadriceps demonstrating significant impairments in CHF, apparent beneficial adaptations of an increased antioxidative capacity were induced in the diaphragm. Nevertheless, muscle ring finger 1 and proteasome activity (markers of protein degradation) were elevated and oxidative enzyme activity failed to increase in the diaphragm of CHF rats, which suggest that a myopathy is likely present in respiratory muscle in CHF, despite its constant activation.