title: The differential effect of aspirin on human platelet activation in aspirin-sensitive asthmatics and normal subjects.
abstract: 1. The in vitro effect of aspirin on platelet aggregation and ATP release induced by platelet activating factor (PAF), arachidonic acid (AA) and collagen (COL) was assessed in 10 aspirin-sensitive (ASP+) asthmatic patients and 10 normal subjects. 2. For PAF, but not AA or COL, both the baseline EC50 and minimum concentration required to produce a maximum response for aggregation were significantly increased in ASP+ asthmatics compared with normal subjects (P < 0.05). Maximum ATP released was greater in ASP+ patients for all agonists but the difference was most significant for PAF (P < 0.025). 3. In ASP+ asthmatics COL induced, but not AA induced, aggregation was less sensitive to inhibition by aspirin compared with normals (P < 0.01). Similarly, analysis of the area under the percent inhibition concentration-response curve showed aspirin to be less effective in inhibiting platelet aggregation induced by PAF in ASP+ asthmatics than in normal subjects (normal subjects: 155 +/- 11 mg% ml-1, ASP+ asthmatics: 115 +/- 19 mg% ml-1; P < 0.05). 4. Regression analysis showed a poor correlation (r = 0.25, P < 0.4933) between the degree of aspirin induced inhibition of ATP release and platelet aggregation induced by PAF in ASP+ asthmatics. 5. The significant differences observed in platelet responses to PAF, COL and to aspirin in ASP+ asthma patients further suggests an abnormality in platelet function exists in this syndrome.
authors: Department of Medicine, University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands.
authors: M L
authors: ML
authors: Taylor
authors: G A
authors: GA
authors: Stewart
authors: P J
authors: PJ
authors: Thompson
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D000704:Analysis of Variance; D016718:Arachidonic Acid / Q000494:pharmacology; D001241:Aspirin / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D001249:Asthma / Q000097:blood* / Q000209:etiology; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D003094:Collagen / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004342:Drug Hypersensitivity / Q000097:blood* / Q000150:complications; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D010972:Platelet Activating Factor / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D012044:Regression Analysis
chemical_list: D010972:Platelet Activating Factor; D016718:Arachidonic Acid; D000255:Adenosine Triphosphate; D003094:Collagen; D001241:Aspirin