Epidermal growth factor (EGF), an essential factor for the proliferation and survival of renal tubular cells, is expressed by distal tubules and normally excreted via urine. Previous studies in rats demonstrated that acute tubular injury reduces urinary EGF levels. However, it is unclear whether urinary EGF is a suitable monitoring marker of tubular repair status after acute kidney injury (AKI) in humans. To address this question, we measured serum and urinary EGF in patients with AKI (n = 99) using ELISA and investigated whether urinary EGF levels were associated with the severity of tubular injury and renal prognosis. Urinary EGF was abundant in healthy controls but showed a significant decrease in AKI patients (14,522 ± 2190 pg/mL vs. 3201 ± 459.7 pg/mL, p < 0.05). The urinary EGF level in patients with renal AKI was notably lower than that in patients with pre-renal AKI. Furthermore, the urinary EGF level in patients with AKI stage 3 was significantly lower than that in patients with AKI stage 1. Urinary EGF levels were negatively correlated with urinary β-2MG and serum creatinine levels but positively correlated with hemoglobin levels and eGFR. Urinary EGF was not significantly correlated with urinary NAG, α-1MG, L-FABP, NGAL, KIM-1, or urinary protein concentrations. No significant correlation was observed between serum and urinary EGF levels, suggesting that urinary EGF is derived from the renal tubules rather than the blood. In living renal transplantation donors, the urinary EGF/Cr ratio was approximately half the preoperative urinary EGF/Cr ratio after unilateral nephrectomy. Collectively, these data suggest that urinary EGF is a suitable noninvasive indicator of not only the volume of functional normal renal tubules but also the status of tubular repair after AKI.

Background Dialysis patients are at a high risk of sarcopenia. To prevent sarcopenia in these patients, exercise programs, especially during dialysis sessions, have recently been used. However, the long-term effects of intradialytic exercise on body composition, physical function, and dialysis adequacy have not been fully elucidated. Methods Fourteen dialysis patients were divided into an ergometer group (n = 8), with intradialytic exercise using an ergometer and the non-ergometer group (n = 6) without intradialytic exercise. Bioimpedance analysis for measuring body composition and physical function tests were performed during the one-year study period. Results There were no patient dropouts from the study. Ergometer exercise increased the percentage change in skeletal muscle mass (non-ergometer 2.01%±2.93% vs. ergometer 6.27%±2.12%, p = 0.005), leg muscle mass (5.85%±12.88% vs. 15.39%±8.78%, p = 0.073), bone mineral content (4.50%±6.18% vs. 9.69%±1.77%, p = 0.036), and decreased the percentage change in body fat percentage (-4.46%±16.30% vs. -14.24%±6.86%, p = 0.098). Lower limb physical function mildly improved, and Kt/V changed to a positive value in the ergometer group. Conclusions One-year intradialytic ergometer exercise increased lower limb muscle mass and bone mineral content, and decreased body fat percentage in dialysis patients. Additionally, it mildly increased physical function and Kt/V. Therefore, intradialytic ergometer exercise could be a promising and sustainable intervention program for improving body composition, physical activity, and dialysis adequacy.

Background Dialysis patients are at a high risk of sarcopenia. To prevent sarcopenia in these patients, exercise programs, especially during dialysis sessions, have recently been used. However, the long-term effects of intradialytic exercise on body composition, physical function, and dialysis adequacy have not been fully elucidated. Methods Fourteen dialysis patients were divided into the non-ergometer group (n = 8) without intradialytic exercise, and the ergometer group (n = 6) with intradialytic exercise at a self-selected intensity using an ergometer. Bioelectrical impedance analysis for measuring body composition and physical function tests were performed during the one-year study period. Results No patients withdrew from the study. Ergometer exercise significantly increased skeletal muscle mass (non-ergometer 2.01% ± 2.93% vs. ergometer 6.27% ± 2.12%, p = 0.005, 95% confidence interval (CI 1.18 to 7.35), and showed a trend toward an increase in leg muscle mass (5.85% ± 12.88% vs. 15.39% ± 8.78%, p = 0.073, 95% CI − 3.82 to 22.90). Furthermore, ergometer exercise significantly increased bone mineral content (4.50% ± 6.18% vs. 9.69% ± 1.77%, p = 0.036, 95% CI 0.52 to 10.91), and tended to decrease body fat percentage (− 4.46% ± 16.30% vs. − 14.24% ± 6.86%, p = 0.098, 95% CI − 25.32 to 5.77). Lower limb physical function tended to improve, and Kt/V exhibited a trend toward an increase in the ergometer group (− 3.54% ± 5.68% vs. 1.52% ± 5.57%, p = 0.061, 95% CI − 1.57 to 3.04). Conclusions A 1 year intradialytic ergometer exercise at self-selected intensity increased skeletal muscle mass and bone mineral content, and tended to reduce body fat percentage in dialysis patients, with no dropouts. Additionally, it mildly increased physical function and Kt/V. This pilot study may provide a novel strategy for sustainable and effective intradialytic exercise therapy for patients undergoing dialysis, warranting further large-scale investigation.