Amino-acid-based peritoneal dialysis solution improves amino-acid transport into skeletal muscle

Abstract

Abnormalities of amino-acid (AA) and protein metabolism are known to occur in chronic kidney disease (CKD). Protein malnutrition may contribute to impaired prognosis of dialysis patients. A crucial step in protein metabolism is AA transport into the cells. We compared the effects of an AA-containing peritoneal dialysis (PD) solution to glucose-based solutions on skeletal muscle AA uptake. Thirteen nondiabetic PD patients were studied twice in a random order and in a crossover manner both in the fasting state and during euglycemic insulin stimulation using [(11)C]methylaminoisobutyrate ([(11)C]MeAIB) and positron emission tomography (PET). Before both PET study days, patients had been using either glucose-based PD solutions only or one daily bag of AA solution in addition to glucose-based PD solutions for at least 6 weeks. Skeletal muscle AA uptake was calculated with graphical analysis. AA-containing PD solution increased plasma AA concentrations from 2.18+/-0.34 to 3.08+/-0.55 mmol l(-1) in the fasting state (P=0.0002) and from 1.88+/-0.15 to 2.42+/-0.30 mmol l(-1) during insulin stimulation (P<0.0001). As compared to PD treatment using glucose-based solutions only, skeletal muscle AA uptake was significantly higher during treatment containing AA solution both in the fasting state (15.2+/-5.8 vs 20.0+/-5.6 micromol kg(-1) min(-1), respectively, P=0.0057) and during insulin stimulation (16.8+/-4.5 vs 21.1+/-4.9 micromol kg(-1) min(-1), respectively, P=0.0046). In conclusion, PD treatment with an AA-containing PD solution is associated with a significant increase in skeletal muscle AA uptake both in the fasting state and during insulin stimulation.