Serotonin levels in platelet-poor plasma and whole blood in people with type 2 diabetes with chronic kidney disease

Patients with diabetes mellitus (DM) are prone to atherosclerosis. Atherosclerosis activates platelets; activated platelets release serotonin, and therefore, evaluation of serotonin levels in blood could be a valuable biomarker for future risk of cardiovascular events.Plasma serotonin levels obtained from patients with DM complicated with chronic kidney disease were measured using HPLC and were compared to serotonin levels of healthy control subjects. Patients with DM were classified into 2 subgroups of mildly (group 1) and moderately/severely (group 2) impaired renal function.Serotonin concentration in platelet-poor plasma for group 1 was significantly higher than that of healthy control subjects (p < 0.01), and was significantly higher than that of patients from group 2 (p < 0.05). The concentration of serotonin in whole blood for group 2 patients was significantly lower than that measured from healthy control subjects (p < 0.01). The ratio of the plasma to whole blood level was significantly elevated in both groups 1 and 2 compared with healthy controls (p < 0.01).Our results indicate that platelets are activated to release serotonin into plasma in diabetic patients with mildly impaired renal function. When renal damage is advanced, platelets are over-activated to release serotonin.