Lipoprotein and apolipoprotein losses during continuous ambulatory peritoneal dialysis

The daily loss of apolipoproteins into the dialysate from 5 patients on continuous ambulatory peritoneal dialysis (CAPD) was measured. The mean excretion of apolipoprotein (apo) AI and apo AII, major proteins of high-density lipoproteins (HDL), were 84 and 17 mg/day, respectively, while that of apo B, a major protein of low-density lipoproteins (LDL) was 39 mg/day. The peritoneal clearance of apo AI and apo AII were similar; both being significantly greater than that of apo B. The fractional catabolic rates of various proteins found in the CAPD dialysate showed molecular sieving effects of the peritoneal membrane and indicated that the apolipoproteins were excreted as lipoproteins. These findings suggest that there is continuous and selective loss of HDL compared to LDL which may also indicate an increased predisposition of these patients to atherosclerosis.