Biochemical analysis of muscle biopsy in overnight fasting patients with severe chronic heart failure

Abstract

To better characterize the role of skeletal muscle in chronic heart failure we studied energetic charge, metabolites and enzyme activity in the energy production pathway. We selected 15 males with severe chronic heart failure (NYHA class III, stable clinical conditions and in normal nutritional status) and seven controls. Controls and patients were submitted to biopsy of the vastus lateralis muscle in resting and fasting conditions. Hormone profiles were also evaluated. Our results showed near normal ATP, ADP and AMP concentrations, but there were substantially more reductions in glycogen (46 ± 5 vs 77 ± 6 μmoles glycosidic units.g-1 fresh tissue) and creatine phosphate (5 ± 1 vs 13 ± 1 μmoles.g-1 fresh tissue) in patients than in We also found a in controls. reduction glycolytic activity (pyruvate kinase 1009 ± 79 vs 1625 ± 26 nmoles.min-1.mg protein-1), despite normal tricarboxylic acid cycle velocity, an increase in alanine aminotransferase (964 ± 79 vs 425 ± 34 nmoles.min-1.mg protein-1) and in aspartate aminotransferase (515 ± 44 vs 291 ± 56 nmoles.min-1.mg protein-1). An increase was also observed in total NADH cytochrome c reductase (128 ± 14 vs 68 ± 5 nmoles.min-1.mg protein-1), while cytochrome oxidase activity was normal. The cortisol/insulin ratio was slightly elevated (77 ± 4 vs 32 ± 12). In conclusion, normonutritive patients with severe heart failure show an imbalance in the energy production/utilization ratio. The impairment is probably due both to a decrease in production and an increase in consumption of energy owing to greater cellular workload and/or a hypercatabolic state.