NUTRITIONAL-STATUS, MUSCLE COMPOSITION AND PLASMA AND MUSCLE FREE AMINO-ACIDS IN RENAL-TRANSPLANT PATIENTS

To investigate the effects of renal transplantation (Rtx) on the nutri tional status, muscle composition and the plasma and muscle free amino acid (AA) pattern, three groups of altogether 30 renal transplant pat ients (group I n = 10; 46 +/- 14 [SD] days after Trx), (group II n = 1 0; 13 +/- 2 months after Rtx) and (group III n = 10; 9 +/- 2 years aft er Rtx) underwent anthropometric measurements, blood sampling and perc utaneous muscle biopsy. The immunosuppressive therapy consisted of pre dnisolone, azathioprine and cydosporine-A. The results were compared w ith data from age-matched healthy subjects. Renal function was impaire d in groups I, II and III. Serum albumin was decreased in groups I and II. The patients of group II had an increased percentage of body fat, triceps and subscapular skin folds and total sum of skinfolds. In gro up I the ratio alkaline-soluble protein (ASP) to DNA, which is a sensi tive index of protein depletion on the cellular level, was decreased. Muscle magnesium content was decreased whereas the muscle DNA, sodium and chloride contents were increased. The mean plasma concentration of most essential AA (EAA) was essentially normal except phenylalanine w hich was increased in groups I and II. Among the nonessential AA (NEAA ), the mean plasma levels of asparagine and citrulline were increased in all groups, whereas alanine and arginine were increased in group I and taurine in group II while the other NEAA were normal. In muscle, t he intracellular free concentrations of isoleucine and threonine in al l groups of patients were increased, whereas the concentrations of leu cine, phenylalanine and valine were increased in groups I and II. Amon g the NEAA, the intracellular muscle levels of asparagine and tyrosine were increased in all groups, whereas intracellular alanine was incre ased in groups I and II, intracellular glycine was increased in groups I and III and intracellular serine was increased in groups II and III . The anthropometric data, the muscle water and electrolyte contents, the protein (ASP/DNA) composition were altered in the patients in grou ps I and II, but essentially normal in the stable renal transplant pat ients in group III. The results indicate that although metabolic and n utritional abnormalities typical for the uremic condition may persist for some time after Rtx, the continuous immunosuppressive therapy incl uding low-dose corticosteroids may not necessarily result in de novo d isturbances in nutritional status. However, specific abnormalities in the amino acid metabolism with increased concentrations of several of the free amino acids in plasma and muscle seem to be present in a larg e proportion of long-term Rtx patients, the mechanism(s) of which rema in to be established.