RETICULATED PLATELETS IN UREMIC PATIENTS - EFFECT OF HEMODIALYSIS ANDCONTINUOUS AMBULATORY PERITONEAL-DIALYSIS

Platelet RNA content can be detected by flow cytometry using thiazole orange staining to identify platelets recently released into the circu lation. We studied platelet RNA content and platelet function in uremi c patients under different treatment regimens. Four groups were studie d: (I) 15 end-stage renal disease (ESRD) patients (10M/5F) on maintena nce hemodialysis (HD); (II) 11 ESRD patients (6M/5F) on continuous amb ulatory peritoneal dialysis (CAPD); (III) 8 patients with chronic rena l failure managed conservatively (5M/3F); and (IV) 34 controls (20M/14 F). A double color labeling technique using a phycoerythrin-tagged ant ibody against glycoprotein Ib (CD42b) and RNA labeling by thiazole ora nge was performed and read by flow cytometry, Aggregation studies were made in platelet-rich plasma using ADP, epinephrine, collagen, arachi donic acid, and ristocetin. In group I, samples were also obtained aft er HD. Platelet counts did not differ among the groups, Aggregation st udies showed a lower response to ADP and ristocetin in the HD patients , but not in the CAPD or in the chronic renal failure patients. The pe rcentage of platelets with high RNA content in group I was significant ly lower than in controls (3.72 +/- 1.72% vs. 9.05 +/- 3.53%, P < 0.01 ), but was also lower than in the remaining groups (I vs. II P < 0.01, and I vs. III P < 0.01). No differences were seen in platelet RNA con tent among groups II (8.67 +/- 2.73%), III (9.14 +/- 3.04%) and IV. In group I, the percentage of reticulated platelets decreased further af ter HD (2.14 +/- 1.09%, P < 0.01). Aggregation studies showed a signif icantly lower response to ADP and ristocetin in group I (P < 0.05), bu t not in groups II or III in comparison with controls. Aggregation res ponse to ADP and ristocetin decreased after HD (P < 0.05). In conclusi on, HD may decrease the percentage of RNA-rich platelets through elimi nation of the younger and more active platelets and worsen the thrombo pathy present in uremic patients. (C) 1995 Wiley-Liss, Inc.