[Ultrastructural changes in platelets of schizophrenia patients: a link with serotonin metabolism and therapeutic efficacy].

Objective: To investigate the effect of olanzapine treatment on the ultrastructure of granulated platelets (GP) and vacuolated platelets (VP) and to find their association with platelet serotonin (PS) content and treatment efficacy in patients with schizophrenia.

Materials And Methods: Platelets of 49 patients with attack-like schizophrenia treated with olanzapine and 31 healthy people were explored. Electron microscopic morphometry of GP and VP was performed to estimate the ultrastructural parameters of platelets. Microfluorimetry was used to measure PS content. RESULTS; The number of pseudopodies in GP and VP were lower after 28 weeks with olanzapine (-13%, p<0.01) as compared to the patients before treatment but the mean platelet area was not changed. Vv of granules was reduced in VP after 8 and 28 weeks of olanzapine (-13%, p<0,05). Vv of vacuoles was increased in GP in 28 weeks with olanzapine vs. 8 weeks with olanzapine (+16%, p<0.01) and in VP in 28 weeks of treatment vs.patients before treatment (+13%, p<0.01). In patients before treatment, Vv of vacuoles in VP was significantly higher in nonresponders as compared to the responders (+11%, p<0.05) and significantly correlated with PS content (r=0.26, p=0.04). The association between the number and Vv of vacuoles in VP before treatment and time point for positive treatment effect was found for the first time.

Conclusion: Ultrastructural changes in Vv of vacuoles in platelets of schizophrenia patients treated with olanzapine are associated with serotonin metabolism and therapeutic efficacy.