title: Defective platelet aggregation in uremia is transiently worsened by hemodialysis.
abstract: Bleeding is a prominent feature of uremia and remains a significant cause of morbidity in hemodialysis (HD)-dependent patients. To measure the impact of the HD procedure, we performed a prospective cross-over study in eight patients placed consecutively for 2-week periods each on low-flux biocompatible polymethylmethacrylate, low-flux complement-activating cuprophane, and high-flux biocompatible polysulfone membranes. The primary measure of platelet function studied was shear-induced platelet aggregation (SIPA), which has been shown to be a physiologically relevant marker of platelet function and involves the interaction of von Willebrand factor (vWf) with platelet membrane glycoproteins (GP) Ib and IIb-IIIa. Flow-cytometric analysis of the surface expression of platelet membrane GP Ib and GP IIb-IIIa was performed using fluorescein isothiocyanate (FITC)-conjugated monoclonal antibodies CD42b and CD41a, respectively. Multivariate analysis did not demonstrate a statistically significant effect of the type of dialysis membrane on platelet aggregation, calcium flux, or thromboxane B2 production. There was a marked decrease of SIPA in HD patients (pre-HD, mean +/- SEM, 19% +/- 3%) compared with normal controls (43% +/- 3%, P < 0.001), with a further decrease after the HD procedure (post-HD, 12% +/- 2%, P = 0.015 compared with pre-HD). This intradialytic decrease in SIPA correlated with a decrease in GP Ib (pre-HD, 385 +/- 21 mean fluorescence intensity [MFI]; post-HD, 285 +/- 21 MFI, P = 0.0001). GP IIb-IIIa was also significantly decreased post-HD (pre-HD, 1,022 +/- 70 MFI; post-HD, 881 +/- 64 MFI, P = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: R
authors.initials: R
authors.lastname: Sreedhara
authors.forename: I
authors.initials: I
authors.lastname: Itagaki
authors.forename: B
authors.initials: B
authors.lastname: Lynn
authors.forename: R M
authors.initials: RM
authors.lastname: Hakim
mesh_terms: D001792:Blood Platelets / Q000737:chemistry; D002118:Calcium / Q000032:analysis; D003167:Complement Activation; D018592:Cross-Over Studies; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects*; D014511:Uremia / Q000097:blood*
chemical_list: D002118:Calcium