Background: Increase in peritoneal membrane permeability (D/P) correlates with systemic and peritoneal markers of inflammation and neoangiogenesis. Monocyte chemoattractant protein-1 (MCP-1, CCL2) is a potent chemoattractant and activator of monocytes/macrophages. We measured the serum (sMCP-1) and dialysate MCP-1 (dMCP-1) concentrations of stable peritoneal dialysis (PD) patients and studied various factors affecting MCP-1 production. We also looked at the correlation of dMCP-1 concentrations with change in D/P over 12 months.
Methods: Forty-five stable prevalent and 6 new PD patients (22 CAPD, 29 APD) were studied. Median PD duration was 21 months (range 1-114). D/P was measured by standardized peritoneal equilibration test (PET). Patients with recent peritonitis within 3 months of the start of study were excluded. MCP-1 concentrations were measured in serum, overnight dialysate and post-PET dialysate, both at baseline and at 12 months by ELISA.
Results: On univariate analysis, post-PET dMCP-1 concentrations positively correlated with sMCP-1 (p=0.0002), duration of PD (p=0.02), dialysate volume (p=0.001), peritoneal creatinine clearance (p=0.0002) and D/P (p=0.001). There was a negative correlation with residual renal function (p=0.001). dMCP-1 concentrations were higher in patients with past peritonitis (p=0.001). On multivariate analysis, factors independently associated with dMCP-1 were sMCP-1 (p=0.003) and past peritonitis (p=0.001). Thirty patients completed this study, and D/P rose by > 0.1 in 20% patients. dMCP-1 concentrations were higher in baseline and 12-month samples in patients with change in D/P >0.1.
Conclusions: We conclude that dMCP-1 concentrations are related to past peritonitis and serum MCP-1. It is difficult to interpret the relationship of dMCP-1 with change in D/P over time due to the small number of patients.