Exercise Training Reduces Muscle Proteolysis in CHF

Training linked to reduction in MuRF-1 in younger and older patients with chronic heart failure

MONDAY, May 7 (HealthDay News) -- Increased expression of MuRF-1, a component of the ubiquitin-proteasome system, is associated with chronic heart failure, and exercise training reduces MuRF-1 levels, according to a study published online May 7 in Circulation.

To investigate the molecular mechanism of muscle atrophy in chronic heart failure and its interaction with aging, Stephan Gielen, M.D., from the Martin Luther University of Halle/Wittenberg in Germany, and colleagues measured the activation of the ubiquitin-proteasome system in 60 patients with chronic heart failure and 60 healthy controls. Participants were categorized based on age (30 aged 55 years or younger and 30 aged 65 years or older), and were randomly assigned to four weeks of supervised endurance training or to a control group. Real-time polymerase chain reaction assays were used to measure expression of cathepsin-L and the muscle-specific E3 ligases MuRF-1 and MAFbx.

At baseline, the researchers found that MuRF-1 expression was significantly higher in patients than healthy controls. After four weeks of exercise training, for patients in both age groups, MuRF-1 mRNA expression was significantly reduced (patients ≤55 years: −32.8 percent [P = 0.02]; patients ≥65 years: −37.0 percent [P < 0.05]).

"MuRF-1, a component of the ubiquitin-proteasome system involved in muscle proteolysis, is increased in the skeletal muscle of patients with heart failure," the authors write. "Exercise training results in reduced MuRF-1 levels, suggesting that it blocks ubiquitin-proteasome system activation and does so in both younger and older chronic heart failure patients."

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