Abstract
Circulatory diseases, particularly atherosclerosis, is the most common cause of death in patients on chronic hemodialysis (HD). Hemostatic factors, such as platelet aggregability (PLAG) and prostaglandins (PG) generated by the platelets and vascular walls, strongly influence on the occurrence and the development of atherosclerosis. In this study, in order to investigate the effect of dialysis membrane materials on PLAG and circulatory PG system, changes of PLAG and plasma PG during HD were determined in ten non-diabetic patients. The patients were dialyzed with regenerated cellulose (cuprophane: CUPR) or synthetic polymer (polymethylmethacrylate: PMMA) membrane. Blood samples were collected periodically before and during HD, and PLAG was measured from the platelet aggregation curve elicited by collagen (CL), ADP or epinephrine (EP). Plasma 6-keto-PGF1α and thromboxane B2 (TXB2) were determined by radioimmunoassay after extraction and purification. Hemodialysis leukopenia was less with PMMA than with CUPR, and platelet counts were not changed with either membranes. Although the PLAG elicited by ADP was no different with the two membranes, the maximal aggregation rate for CL (0.5mcg/ml) or EP (1mcM) was significantly more reduced in PMMA than in CUPR (CL at 15min: 44±10 [mean±SD] vs 73±7%, p<0.01; EP at 60min: 36±4 vs 58±9%, p<0.025). Plasma 6-keto-PGF1α increased after starting HD, then tended to return to pre-dialysis levels with both PMMA (261±76, 519±137, 381±83pg/ml for pre-HD, 15min, 120min respectively) and CUPR (237±67, 513±89, 358±41pg/ml for pre-HD, 15min, 120min respectively). On the other hand, plasma TXB2 increased and remained high during HD with CUPR (401±35, 822±194, 635±70pg/ml for pre-HD, 15min, 120min respectively), but did not change significantly with PMMA (420±97, 395±75, 381±53pg/ml for pre-HD, 15min, 120min respectively). These results suggest that HD with PMMA membrane compared to CUPR may exert a more favorable effect on the hemostatic system and may inhibit the progression of atherosclerosis in dialyzed patients.
