Influence of serotonin-transporter-linked promoter region polymorphism on platelet activation in geriatric depression

Objective: Depression has been associated with increased platelet activation. Variations in the serotonin-transporter-linked promoter region (5-HTTLPR) polymorphism may influence the degree of activation. The authors examined the association among depression, platelet activation, and 5-HTTLPR genotype. Method: Elderly subjects with (N=61) and without (N=12) major depression were assessed for cognitive impairment, cardiovascular disease, and two indices of platelet activation. The depressed subjects were genotyped for the 5-HTTLPR polymorphism. Results: The depressed subjects were older, were more cognitively impaired, and had higher platelet factor 4 and beta -thromboglobulin levels; cardiovascular disease was minimal in both groups. In the depressed group, subjects with the 5-HTTLPR I/I genotype had significantly higher platelet factor 4 and beta -thromboglobulin levels. Conclusions: Platelet activation is increased in elderly depressed patients, especially those with the 5-HTTLPR I/I genotype. This finding suggests how genetic differences may influence cardiovascular mortality in depressed patients with ischemic heart disease.