Age-related augmentation of stroke tendency evaluated using plasma P-selectin levels

Plasma soluble P-selectin is thought to be a useful marker for thrombotic diseases. To evaluate the thrombotic state and risk of stroke in aged healthy subjects, we investigated plasma P-selectin levels in healthy subjects and ischemic stroke patients. Plasma P-selectin was measured in 67 healthy subjects and 35 aged (>or= 65 years of age) patients with chronic ischemic stroke using a sandwich enzyme-linked immunosorbent assay (ELISA). Plasma P-selectin was significantly higher in aged (>or= 65 years of age) healthy subjects than in young (< 65 years of age) healthy subjects. Significant difference did not exist between aged healthy subjects and aged stroke patients who were not receiving anti-platelet agents. Anti-platelet agent had no significant effect on plasma P-selectin levels in aged stroke patients. The amounts of P-selectin released from platelets into the plasma after stimulation with adenosin diphosphate in young and aged healthy subjects were not significantly different. Elevated levels of P-selectin in aged healthy subjects suggests the existence of a subclinical thrombotic state which can result in a stroke. Elevated P-selectin levels are not thought to be due to platelet hyperfunction.