In Vitro Effect of Intermedin/Adrenomedullin 2 on Platelet Aggregation in Human

Abstract

SUMMARY Intermedin/Adrenomedullin 2 (IMD/AM2) is a novel peptide related to the calcitonin gene-related peptide family. It is a vascular regulatory factor of homeostasis and a vital endogenous protective factor against vascular diseases. This in vitro study was designed to the effect of IMD/AM2 on platelet aggregation with several platelet aggregation agents in the healthy volunteers. The study was carried out on 7 healthy volunteers. Blood samples were centrifuged to prepare platelet-rich plasma and platelet-poor plasma. The platelet-rich plasma was diluted with the platelet poor plasma to yield test platelet-rich plasma with a final platelet count of 300,000±25,000 platelets L−9. Three concentration of IMD/ AM2 solutions were prepared that would result in 10-8, 10-7, and 10-6 M. Each concentration of IMD/AM2 was incubated with platelet-rich plasma at 37 C during one hour. Platelet aggregation studies were carried out in platelet-rich plasma using 3μg ml−1 collagen, 10μM ADP, and 10μM epinephrine. In addition, spontaneous aggregation was performed for each concentration of IMD/AM2 incubated platelet-rich plasma. Compared to control, pre-incubation with all dilutions of IMD/AM2 had no detectable effect on platelet aggregation response induced collagen, ADP, epinephrine, and no detected spontaneous aggregation. The platelet aggregation amplitudes and slopes were statistically similar among all groups by the aggregation test. This in vitro study suggested that IMD/AM2 had no effect on platelet aggregation in a dose-dependent manner.