A vitamin E-coated polysulfone membrane reduces serum levels of inflammatory markers and resistance to erythropoietin-stimulating agents in hemodialysis patients: results of a randomized cross-over multicenter trial.

BACKGROUND: Oxidative stress is prevalent in dialysis patients and has been implicated in the pathogenesis of cardiovascular disease and anemia. Vitamin E is a fat-soluble antioxidant that plays a central role in reducing lipid peroxidation and inhibiting the generation of reactive oxygen species. The aim of this cross-over randomized study was to compare the effects of a vitamin E-coated polysulfone (Vit E PS) membrane and a non-vitamin E-coated polysulfone (PS) membrane on inflammatory markers and resistance to erythropoietin-stimulating agents (ESAs). METHODS: After a 1-month run-in period of standard bicarbonate dialysis with a synthetic membrane, 62 patients of both genders, and older than 18 years, dialysis vintage 48 ± 27 months, BMI 22 ± 3 (from 13 different dialysis units) were randomized (A-B or B-A) in a cross-over design to Vit E PS (treatment A) and to PS (treatment B) both for 6 months. C-reactive protein (CRP) and interleukin-6 (IL-6) concentrations were determined by a sandwich enzyme immunoassay at baseline and every 2 months; red blood cell count, ESA dose and ESA resistance index (ERI) were assessed monthly. RESULTS: Hemoglobin (Hb) levels significantly increased in the Vit E PS group from 11.1 ± 0.6 g/dl at baseline to 11.5 ± 0.7 at 6 months (p < 0.001) and remained unchanged in the PS group. Although ESA dosage remained stable during the observation periods in both groups, ERI was significantly reduced in the Vit E PS group from 10.3 ± 2.2 IU-dl/kg/g Hb week at baseline to 9.2 ± 1.7 at 6 months (p < 0.001). No significant variation of ERI was observed in the PS group. A significant reduction in plasma CRP and IL-6 levels was observed in the Vit E PS group: CRP from 6.7 ± 4.8 to 4.8 ± 2.2 mg/l (p < 0.001) and IL-6 from 12.1 ± 1.4 to 7.5 ± 0.4 pg/ml (p < 0.05). In the PS group, CRP varied from 6.2 ± 4.0 to 6.4 ± 3.7, and IL-6 from 10.6 ± 2.1 to 9.6 ± 3.5 (p = n.s.). CONCLUSIONS: Treatment with Vit E PS membranes seems to lead to a reduction in ESA dosage in HD patients; in addition, a low chronic inflammatory response may contribute to a sparing effect on exogenous ESA requirements.

Effects of exercise training on exercise aerobic capacity and quality of life in hemodialysis patients.

BACKGROUND: Physical and aerobic capacity are extremely limited in dialysis patients, but it is uncertain whether or not exercise training is safe or has beneficial effects. This study aimed to assess the effects of exercise training on functional capacity and quality of life of hemodialysis patients. METHODS: Ten hemodialysis patients (7 men, 3 women, aged 37 +/- 7 years) free from severe comorbidities were recruited. They underwent training sessions (up to 90 minutes of submaximal exercise) twice a week, on nondialysis days, for 12 months. At baseline and after the physical training program, all patients underwent biochemistry, cardiopulmonary exercise test, echocardiography and a self-rated health test (SF-36). RESULTS: At baseline, dialysis patients showed impaired VO2 uptake (20.6 +/- 5.0 ml/kg/min vs. 34.2 +/- 6.0 ml/kg/min, p<0.001) and peak working capacity (115 +/- 36 W vs. 192 +/- 46.7 W, p<0.001) compared with normal controls. Following the training program, both peak VO2 (20.4 +/- 4.9 ml/kg/min vs. 25.1 +/- 6.5 ml/kg/min, p<0.05), VO2 at anaerobic threshold (12.8 +/- 1.9 ml/kg/min vs. 15.1 +/- 3.8 ml/kg/min, p<0.05), peak working capacity (113 +/- 33 W vs. 134 +/- 37 W, p<0.01) and SF-36 scores improved. No side effects related to intervention occurred. CONCLUSIONS: Dialysis patients showed impaired muscular exercise capacity, but 12 months of moderate exercise training was able to improve their physical function, aerobic capacity and quality of life. Our study suggests that mild, regular physical activity should be recommended and encouraged as an important aspect of the care of selected dialysis patients.