title: Circulating reticulated platelets in the early and late phases after ischaemic stroke and transient ischaemic attack.
abstract: The percentage of reticulated platelets (% RP) could be a useful marker of increased platelet production and/or turnover in patients with increased platelet activation, but few flow cytometric studies have measured the % RP in patients with ischaemic cerebrovascular disease (CVD). Whole blood flow cytometry using thiazole orange was performed to compare the % RP in patients in the early (1-27 d, n = 79) and late phases (79-725 d, n = 70) after ischaemic stroke or transient ischaemic attack (TIA) with controls without CVD (n = 27). The impact of aspirin dose escalation (75-300 mg/d) on the % RP was investigated in 10 patients in the late phase after stroke/TIA. The platelet count and mean platelet volume (MPV) were similar in CVD patients and controls. Compared with controls, the unadjusted % RP was not significantly higher in early or late phase CVD patients (P < or = 0.3). However, having adjusted for age, the % RP was higher in early (P = 0.047) and late phase CVD patients (P = 0.01). There was a positive correlation between % RP and MPV in EDTA- and citrate-anticoagulated blood in both early and late phase CVD patients (P< or = 0.01). The % RP was not significantly influenced by aspirin dose. These data do not convincingly support an excessive stimulus to platelet production in the early or late phases after ischaemic stroke/TIA, but are consistent with the hypothesis that reticulated platelets are larger than more mature 'non-reticulated' platelets in ischaemic CVD.
authors.affiliation: Stroke Research Group, Institute of Neurology, The National Hospital for Neurology and Neurosurgery, University College London, London, UK. d.mccabe@ion.ucl.ac.uk
authors.forename: Dominick J H
authors.initials: DJ
authors.lastname: McCabe
authors.forename: Paul
authors.initials: P
authors.lastname: Harrison
authors.forename: Paul S
authors.initials: PS
authors.lastname: Sidhu
authors.forename: Martin M
authors.initials: MM
authors.lastname: Brown
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Machin
mesh_terms: D000368:Aged; D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000473:pathology*; D002545:Brain Ischemia / Q000097:blood / Q000188:drug therapy; D048429:Cell Size; D004305:Dose-Response Relationship, Drug; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D002546:Ischemic Attack, Transient / Q000097:blood* / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010976:Platelet Count; D020521:Stroke / Q000097:blood* / Q000188:drug therapy
chemical_list: D005343:Fibrinolytic Agents; D010975:Platelet Aggregation Inhibitors; D001241:Aspirin