Grant: Operating Grant

Platelets are circulating blood particles normally responsible for stopping bleeding by forming blood clots (platelet aggregates). In conditions such as heart attack and stroke blood clots form inappropriately in sick (atherosclerotic) blood vessels. Recently, we have discovered that two types of platelets exists. One type of platelet generates the signaling molecule nitric oxide and the other type of platelet does not generate this signaling molecule. Nitric oxide is well known to inhibit platelet clot formation. Hence, we propose that platelets that do not generate nitric oxide initiate clot formation, while platelets that do generate nitric oxide limit clot formation. Hence, the purpose of our studies are 1) to investigate the biochemical and structural differences between the two platelet subtypes, 2) to investigate whether the two platelet subtypes play different roles in clot formation, and 3) to study whether patients with cardiovascular disease (specifically those having had a stroke) have altered ratios of one type of platelet to another. By the end of our studies we expect to have established that the two platelet subtypes differ biochemically and structurally, have different roles in clot formation, and that stroke patients have elevated levels of platelets which initiate clot formation. These basic and translational studies of platelet biology have the potential to significantly impact the health of Canadians by better predicting risk and extent of clot formation.