Exercise improves albumin fractional synthetic rate in chronic hemodialysis patients

European Journal of Clinical Nutrition (2007) 61, 686689 & 2007 Nature Publishing Group All rights reserved 0954-3007/07 $30.00 www.nature.com/ejcn

SHORT COMMUNICATION Exercise improves albumin fractional synthetic rate in chronic hemodialysis patients

LB Pupim, PJ Flakoll (In memoriam) and TA Ikizler

Department of Medicine, Division of Nephrology, Vanderbilt University School of Medicine, Nashville, TN, USAObjective: To determine whether exercise augments the improvements in fractional synthetic rate (FSR) of albumin observed with nutrition alone.

Design: Randomized crossover study. Each patient randomly participated in two protein metabolism kinetic studies using primed-constant infusion of (13C) leucine 2 h before, during and 2 h after hemodialysis. Plasma enrichments of (13C) leucine and (13C) ketoisocaproate were examined to determine the FSR of albumin.

Setting: General Clinical Research Center at Vanderbilt University Medical Center.

Subjects: Five chronic hemodialysis (CHD) patients.

Interventions: Intra-dialytic parenteral nutrition (IDPN) with or without exercise.

Results: Exercise performance during hemodialysis significantly improves the FSR of albumin beyond what is observed with IDPN alone (26.273.1% per day versus 17.771.9% per day, Po0.05).

Conclusion: Exercise improves albumin fractional synthetic rate beyond what is observed with IDPN alone in the acute setting in CHD patients.

European Journal of Clinical Nutrition (2007) 61, 686689. doi:10.1038/sj.ejcn.1602578; published online 20 December 2006 Keywords: albumin; catabolism; hemodialysis; synthesis; exercise

Introduction Chronic hemodialysis (CHD) patients suffer from muscle wasting and decreased visceral protein stores, which significantly impacts their death and hospitalization (USRDS, 1999). We have shown that intra-dialytic parenteral nutrition (IDPN) reverses hemodialysis (HD)-induced catabolism (Ikizler et al., 2002; Pupim et al., 2002), including the fractional synthetic rate (FSR) of albumin (Pupim et al., 2004a), a direct estimate of acute changes in hepatic albumin synthesis (De Feo et al., 1991; Barazzoni et al., 1999; Ahlman et al., 2001). As the beneficial effects of IDPN on somatic protein stores are further augmented by the addition of exercise (Pupim et al., 2004b), we hypothesized that exercise performance combined with IDPN during a single HD treatment would lead to a more profound increase in albumin FSR compared to what is observed with IDPN alone.

Subjects and methods Analyses were conducted as part of a study from which data on whole body and muscle protein homeostasis have already been reported (Pupim et al., 2004b). Out of the six subjects previously...