Effect of remote ischaemic conditioning on platelet aggregation and platelet turnover

Remote ischaemic conditioning (RIC) is a new beneficial treatment for patients with ST-elevation myocardial infarction. RIC may inhibit thrombus formation and, therefore, we investigated whether RIC affects platelet aggregation and turnover. 30 healthy male volunteers were subjected to intervention on day 1 (sham intervention, no aspirin), day 2 (RIC, no aspirin), and day 16 (RIC, treated 7days with aspirin 75mg/day). RIC was performed as four cycles of 5min interchangeable inflation and deflation using an automated cuff. Blood samples were collected 5min before, as well as 5 and 45min after RIC. Platelet aggregation was measured by Multiplate (R) using collagen (COLtest), adenosine diphosphate (ADPtest), and arachidonic acid (ASPItest) as agonists. Platelet turnover was evaluated by flow cytometry. Serum thromboxane B-2 was determined by ELISA to confirm aspirin compliance. We found no significant change in platelet aggregation at visit 1 (COLtest: p=0.32; ADPtest: p=0.24; ASPItest: p=0.07), visit 2, except for ADP-induced platelet aggregation evaluated 5min after RIC (COLtest: p=0.39; ADPtest: p=0.02; ASPItest: p=0.39), or visit 3 (COLtest: p=0.48; ADPtest: p=0.61; ASPItest: p=0.90). Platelet turnover was not influenced by RIC, neither on nor off aspirin (all p-values>0.07). (1) RIC did not affect platelet aggregation in healthy young men. (2) RIC did not affect platelet turnover in healthy young men. (3) Aspirin did not influence the effect of RIC on platelet aggregation and turnover. (4) Future studies exploring the effect of RIC on platelet aggregation and turnover in patients with ischaemic heart disease are warranted.