Skeletal muscle protein turnover responses to parenteral nutrition in patients with alcoholic liver cirrhosis and sarcopenia

Alcoholic liver cirrhosis (ALC) is accompanied by sarcopenia. The aim of this study was to investigate the acute effects of balanced parenteral nutrition (PN) on skeletal muscle protein turnover in ALC. Eight male patients with ALC and seven age- and sex-matched healthy controls were studied for three hours of fasting followed by three hours of intravenous PN (SmofKabiven 1206 mL: Amino acid 38 g, carbohydrates 85 g, fat 34 g) 4 ml/kg/hour. We measured leg blood flow, sampled paired femoral arterio-venous concentrations and quadriceps muscle biopsies while providing a primed continuous infusion of [ring-2D5]-phenylalanine to quantify muscle protein synthesis and breakdown. Patients with ALC exhibited shorter 6-min walking distance (ALC: 487 ± 38 vs. controls: 722 ± 14 m, p<0.05), lower hand-grip strength (ALC: 34 ± 2 vs. controls: 52 ± 2 kg, p<0.05), and CT-verified leg muscle loss (ALC: 5922 ± 246 vs. controls: 8110 ± 345 mm2, p<0.05). Net leg muscle phenylalanine uptake changed from negative (muscle loss) during fasting to positive (muscle gain) in response to PN (ALC: -0.18 ± +0.01 vs. 0.24 ± 0.03 µmol/kg muscle*min-1; p <0.001 and controls: -0.15 ± 0.01 vs. 0.09 ± 0.01 µmol/kg muscle*min-1; p <0.001), but with higher net muscle phenylalanine uptake in ALC than controls (p <0.001). Insulin concentrations were substantially higher in ALC patients during PN. Our results suggest a higher net muscle phenylalanine uptake during a single infusion of PN in stable ALC patients with sarcopenia compared with healthy controls.