Role of platelet surface receptor abnormalities in the bleeding and thrombotic diathesis of uremic patients on hemodialysis and peritoneal dialysis

Background. Patients with chronic renal failure suffer from bleeding diathe sis and a tendency to accelerated atherosclerosis. Altered platelet functio n plays a well defined role in the hemorrhagic complications of these patie nts and has a probable impact on atherothrombotic disease in uremia. In thi s study we investigated the expression of platelet surface receptors, the g lycoprotein GP1b (receptor for von Willebrand Factor(vWF) and GPllb/llla (r eceptor for fibrinogen) in patient with chronic renal failure in pre-dialys is status, under hemodialysis and peritoneal dialysis treatment, in order t o assess the impact of the abnormal receptorial status of uremic platelets on the clinical manifestations of hemostatic alterations in uremic patients . Methods. Thirty-seven normal healthy subjects (controls = Group A), 18 pati ents with mild chronic renal failure (creatinine = 1.8 +/- 0.5mg% - Group B ), 15 patients with advanced renal failure (creatinine = 5.4 +/- 2.1mg% - G roup C), 18 hemodialysis patients (Group D) and II peritoneal dialysis pati ents (Group E) were included in the study The expression of platelet surfac e receptors GP1b and GPllb/llla was investigated with monoclonal antibodies CD42 and CD41 (Immunotech, Marseille, France) and a FACScan flowcytometer (Becton-Dickinson, USA). Results. Mean Values of GPlb glycoprotein (mean flow +/- SD) were: group A = 48. 14 +/- 9.31; group B=40.48 +/- 8.18 (p < 0.005); group C = 34.05 +/- 7.55 (p < 0.0005) versus group A; p = 0.025 versus group B); group D = 34.5 1 +/- 7.22 (p < 0.0005 versus group A; p = 0.025 group B and p = ns versus group G; group E = 26.34 +/- 4. 06 (p < 0.0005 versus group A, p < 0.0005 v ersus group B, p < 0.005 versus groups C and D). Mean values of glycoprotei n GPllb/llla were: group A = 375.32 +/- 90.58; group B = 398.48 +/- 54.26 ( p = ns); group C = 426.86 +/- 52.78 (p < 0.025 versus group A; p = ns versu s group B); group D = 425.17 +/- 75 03 (p < 0.025 versus group A; p = ns ve rsus groups B and C); group E = 336.39 +/- 43.26 (p = ns versus group A; p < 0.005 versus group B, p < 0.0005 versus group C and p < 0.001 versus grou p D). Conclusions. Our data confirm the receptorial defect of glycoprotein GP1b ( the receptor for VWF) on the surface of uremic platelets: a negative correl ation between serum creatinine and the expression of glycoprotein GPlb was found. The defect was not corrected by hemodialysis and/or peritoneal dialy sis. Hemodialysis and peritoneal dialysis have a different impact on the ex pression of GPllb/llla glycoprotein (the receptor for VWF): peritoneal dial ysis seems to have a more favourable effect by restoring normal values of t he expression of this membrane integrine. Theoretically the data could be c orrelated to the better biocompatibility of the peritoneal dialysis and to more favorable clinical behaviour in terms of accelerated atherosclerosis a nd athero-thrombotic complications in the uremic patients with end stage re nal disease. Finally the abnormalities of platelet surface receptors may pl ay a main role in the hemostatic alterations of uremic patients.