Abstract: Objective To investigate the relationship between peritoneal charge barrier and peritoneal protein loss in continuous ambulatory peritoneal dialysis (CAPD) patients, we determined the peritoneal charge barrier and then compared the charge barrier and peritoneal protein loss between CAPD patients with the primary disease of diabetes nephropathy (DN group) and those with the primary disease of chronic glomerulonephritis (CGN group). Method Blood sample and peritoneal fluid were collected. Peritoneal charge barrier was evaluated by the ratio of clearance of pancreatic isoamylase (Cpam) to clearance of salivary isoamylase (Csam) (Cpam/Csam). Protein loss in peritoneal fluid was measured as well. Result ① In the 32 CAPD patients we investigated, Cpam/Csam was 6.296±21.514 and protein in peritoneal fluids was 4.14±1.91g. ② Protein in peritoneal fluid was higher in DN group than in CGN group (5.61±0.86g vs. 4.35±1.88g,P＝0.011), but charge barrier was lower in DN group than in CGN group (0.68±0.86 vs. 9.94±28.35, P＝0.017). ③ Cpam/Csam was negatively correlated with peritoneal protein loss (r = -0.584, P＜0.01), and the natural logarithm of Cpam/Csam was also linearly correlated with the protein loss. Conclusion In CAPD patients, the loss of charge barrier on peritoneum promotes the loss of protein in peritoneal fluid. In these patients, the peritoneal microvascular damage, the decrease of peritoneal charge barrier and the loss of peritoneal protein are proportionately correlated.

Key words: Peritoneum, Charge barrier, Amylase