Effect of using ultrapure dialysate for hemodialysis on the level of circulating bacterial fragment in renal failure patients.

BACKGROUND Cardiovascular disease is the major cause of mortality and morbidity in dialysis patients. Recently, circulating endotoxin is found to associate with the systemic inflammatory state and cardiovascular disease of dialysis patients. Previous studies showed that the use of ultrapure dialysate for hemodialysis could reduce the exposure to exogenous endotoxin. We studied the effect of using ultrapure dialysate for hemodialysis on circulating endotoxin and bacterial DNA fragment levels and vascular stiffness. METHODS This is an open-labeled prospective study of 25 patients (14 male). Circulating endotoxin and bacterial DNA level, vascular stiffness as represented by arterial pulse wave velocity (PWV), nutrition and hydration status were monitored before and repeatedly throughout 12 months after the use of ultrapure dialysate for hemodialysis. RESULTS The average age was 58.9 ± 10.2 years; 21 patients completed the study. Within 4 weeks of conversion to ultrapure dialysate for hemodialysis, the plasma endotoxin level fell from 0.302 ± 0.083 to 0.209 ± 0.044 EU/ml (p < 0.0001) and then remained static, while serum bacterial DNA level remained similar. Furthermore, the time-averaged plasma endotoxin level during the study period significantly correlated with serum C-reactive protein level (r = 0.483, p = 0.017), carotid-femoral PWV (r = 0.455, p = 0.033), and malnutrition inflammation score (r = 0.461, p = 0.031). The time-averaged serum bacterial DNA level significantly correlated with malnutrition inflammation score (r = 0.550, p = 0.008) and inversely with subjective global assessment score (r = -0.543, p = 0.009), but not with PWV. CONCLUSIONS In hemodialysis patients, circulating endotoxin level is associated with vascular stiffness and systemic inflammation. Using ultrapure dialysate for hemodialysis effectively reduces circulating endotoxin level in hemodialysis patients. The long-term benefit of using ultrapure dialysate for hemodialysis requires further study.