虚血性心疾患患者の血小板プロスタサイクリン受容体動態

抄録

We hypothesized that functional changes of prostacyclin receptors were involved in exerciseinduced activation of platelets in patients with ischemic heart disease (IHD). Submaximal treadmill test, using the modified Bruce protocol, was performed in 12 IHD patients (10 angina pectoris and 2 old MI) and 12 age- and sex-matched control subjects.
In IHD patients, plasma TXB₂ levels increased significantly after exercise (p<0.02), suggesting activation of platelets during exercise. However, in controls, TXB₂ levels either decreased or remained constant. Inhibition of platelet aggregation by prostacyclin was blunted after exercise in IHD patients (p<0.01), whereas in controls, inhibition by the agent was enhanced significantly (p<0.01). The changes of anti-aggregatory property of prostacyclin after exercise correlated with the change of activation of the AC by prostacyclin (r=0.766, p<0.05).
We conclude that impaired sensitivity of the platelets to prostacyclin might be relevant to platelet activation associated with exercise in IHD patients.