Impaired Muscle Oxygen Metabolism in Uremic Children: Improved After Renal Transplantation

Background: The purpose of this study is to clarify skeletal muscle oxidative metabolism in children with end-stage renal disease (ESRD) before and after renal transplantation. Methods: We examined muscle oxygenation and metabolism by using noninvasive near-infrared spectroscopy in 10 patients (age, 12.4 ± 3.1 years) 1 week before and 4 weeks after renal transplantation and in 10 controls (age, 12.8 ± 2.6 years) during submaximal hand-grip exercise using the flexor digitorum superficialis muscle. We used 2 indicators to evaluate muscle metabolism. The rate of initial decrease in hemoglobin/myoglobin deoxygenation during arterial occlusion after exercise relative to the value at rest (S2/S1) was used as an indicator of mitochondrial oxygen consumption, whereas recovery time (TR) after exercise was used as an indicator of oxygen delivery to the muscle and aerobic capacity. Results: S2/S1 and TR after exercise were significantly lower in patients before renal transplantation compared with the control group (P < 0.05). S2/S1 and TR after exercise improved significantly after renal transplantation (P < 0.01, P < 0.05) and were not significantly different from those of controls. Conclusion: Oxidative metabolism in skeletal muscle during exercise is impaired in children with ESRD and recovers after renal transplantation.