Effect of renin-angiotensin system inhibitors on prevention of peritoneal fibrosis in peritoneal dialysis patients

Aim: Long-term peritoneal dialysis (PD) may lead to peritoneal fibrosis and ultrafiltration failure. It had been demonstrated that the renin-angiotensin system (RAS) plays a key role in the regulation of peritoneal function in rats on PD. We investigated the effects of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) on long-term PD patients. Methods: We analyzed data from 66 patients treated with PD therapy at our centre for at least 12 months retrospectively, during which time at least two peritoneal equilibration tests (PET) were performed. Thirty-eight patients were treated with ACE/angiotensin II (AII) inhibitors (ACE/ARB group); the other 28 received none of the above drugs during the entire follow up (control group). The expression of fibronectin, transforming growth factor-beta 1 (TGF-beta 1), Aquaporin1 (AQP1) and vascular endothelial growth factor (VEGF) in the overnight effluent were examined by enzyme-linked immunosorbent assay. Results: The demographic data of the two groups showed no difference during the study. No difference between the groups was found with respect to residual renal function (RRF) at the start for both groups by the end of follow up, decreased in the vast majority of patients from both groups (P = 0.014). After 12 months, a significant difference in ultrafiltration was found between the two groups: in the control group it had decreased, while it had not changed in the ACE/ARB group (P < 0.05). In comparison with the baseline level, expression of fibronectin, TGF-beta 1 and VEGF in dialysate effluent were significantly increased except for AQP1 in the control group (P < 0.05), but not in the ACE/ARB group (P > 0.05). Conclusion: The findings suggest that ACE/AII inhibitors appeared to have a slower rate of decline in ultrafiltration and RRF, effectively protect against peritoneal fibrosis in long-term peritoneal dialysis. Long-term follow up seems to be required to draw more conclusions.