Increased muscle protein breakdown in chronic hemodialysis patients with type 2 diabetes mellitus

Background. The presence of diabetes mellitus (DM) in chronic hemodialysis (CHD) patients has potential to increase body protein losses and muscle wasting. Methods. In this study, we examined whole-body and skeletal muscle protein metabolism in 6 CHD patients with type 2 (T2) DM (2 male, 44.4 +/- 6.1 years old, 2 white/4 African American HbA(1)C = 9.5 +/- 1.1%), and 6 non-DM CHD patients (2 male, 43.3 +/- 6.7 years old, 2 white/4 African American) in a fasting state, using a primed-constant infusion of L-(1-C-13) leucine and L-(ring-H-2(5)) phenylalanine. Results. CHD patients with T2DM had significantly increased (83%) skeletal muscle protein breakdown (137 +/- 27 vs. 75 +/- 25 mu g/100 mL/min). There was no significant difference in muscle protein synthesis between groups (78 +/- 27 vs. 66 +/- 21 mu g/100 mL/min, for DM and non-DM respectively), resulting in significantly more negative net protein balance in the muscle compartment in the DM group (-59 +/- 4 vs. -9 +/- 6 mu g/100 mL/min, P < 0.05). A similar trend was observed in whole-body protein synthesis and breakdown. Plasma glucose levels were 113 +/- 16 and 71 +/- 2 mg/dL, P < 0.05, and insulin levels were 25.3 +/- 9.6 and 7.3 +/- 1.0 uU/mL, for DM versus non-DM, respectively, P < 0.05. No significant differences between DM and non-DM were found in other metabolic hormones. Conclusion. The results of this study demonstrate that CHD patients with T2DM under a suboptimal metabolic control display accelerated muscle protein loss compared with a matched group of non-DM CHD patients.