Clinical Investigation Of Relationship Between Peritoneal Monocyte/Macrophage And Peritoneal Solute Transport Rate

Background:Peritoneal solute transport rate (PSTR) is reportedly associated with survival in peritoneal dialysis patients, and fast PSTR was correlated with high mortality. Many factors might explain variability in STR, but the machenism remain uncertain. The aim of this study was to investigate the relationship between percentage of peritoneal monocyte/macrophage in peritoneal dialysis effluent (PDE) and PSTR and explore the machenism.Methods:Overnight (8-10-hour) PDE (with glucose2.5%) collected from40incident PD outpatients (duration<3months) and23long-term PD outpatients (duration>12months) in the2nd and3rd Xiang Ya hospital were investigated. The population of peritoneal cells was studied by flow cytometry analysis, especially the percentage of monocyte/macrophages. Overnight dialysate level of VEGF, TNF-α, IL-10were measued. Serum level of albumin and hsCRP were also assessed. Peritoneal equilibration test (PET) was used to evaluate PSTR. Patients were divided into two groups:high-average and high transporters(H/A;D/P Cr>0.65) and low-average and low transporters(L/A;D/P Cr<0.64). Baseline dialysate-to-plasma ratio for creatinine (D/P Cr) was determined within3months of PD induction. Collected clinical data consisted of information on underlying causes of end-stage renal disease, demographic details (age, gender), comorbidity and measurements of height, weight. All analyses were performed using software SPSS13. Comparisons between two groups were performed using Student's t-test. The chi-squared test was used for categorical variables. Correlation coefficients were calculated by Pearson correlation analysis. Factors associated with peritoneal permeability were assessed by multiple linear regression analysis.Results:Among the incident PD patients, percentage of monocyte/macrophages (0.57±0.49vs3.67±4.46, P<0.05)and dialysate appearance rate of VEGF (128.1±62.4vs43.7±35.6, P<0.001) were higher in the H/A than the L/A; but serum albumin level were lower in the H/A than the L/A(33.8±5.3vs37.7±3.7, P<0.05). Baseline D/P Cr was positively correlated with percentage of monocyte/macrophages (R=0.683, P<0.001), dialysate appearance rate of VEGF (R=0.561, P<0.001), and negatively correlated with serum albumin (R=0.440, P=0.005). However, baseline peritoneal permeability was not correlated with serum C-reactive protein, TNF-α or other clinical factors. The ratio of monocyte/macrophages in incident patient was positively correlated with dialysate appearance rate of VEGF (R=0.586, P<0.001). On multiple linear regression analysis, the ratio of monocyte/macrophages in overnight dialysate was an independent factor influencing baseline peritoneal permeability (P<0.001). D/P Cr of Long-term patients was positively correlated with dialysate appearance rate of VEGF (P<0.05), but correlation with other clinical or laboratory parameters were not found.Conclusions:The number of peritoneal monocyte/macrophage in peritoneal dialysate is correlated with peritoneal transport characteristic and is a potent determinant of baseline peritoneal transport rate. Macrophage infiltration probablely changes peritoneal solute transport rate via expressing VEGF. However, the number of peritoneal monocyte/macrophage is not related with peritoneal permeability in long-term patients.