Evaluation of Platelet Glutamate Dehydrogenase Activity in Late-Life Depressions

Abstract

The aim of the study is to evaluate the activity of platelet glutamate dehydrogenase (GDH) in late-life depression compared to the healthy control group and to reveal possible correlations with clinical data. Patients and methods: 42 elderly patients (60–86 years old) with depressive episodes of different nosological categories according to ICD-10 were examined: a single depressive episode (F32.0, F32.1), a depressive episode in recurrent depressive disorder (RDD — F33.0, F33.1) and a depressive episode in bipolar affective disorder (BD — F31.3). The activity of GDH and the severity of depression (using the Hamilton depressive scale, HAMD-17, and the Hamilton scale for assessing anxiety, HARS) were evaluated twice: before the starting the course of antidepressant therapy (day 0) and on the 28th day of the treatment course. Results: patients showed a significant decrease in the activity of GDH compared to the control group (p < 0.0008). Before the treatment, GDH activity was significantly reduced compared to the control in both RDD and BD (p < 0.002 and p < 0.004), whereas after the treatment, the decreased GDH activity was observed only in patients with BD (p < 0.002). When compared with the control group, male patients showed a significant decrease in GDH activity both before and after the treatment course (p < 0.017 and p < 0.027), whereas women patients showed the decrease only before the treatment (p < 0.014). Conclusion: the decreased platelet GDH activity in elderly depressions may indicate an impairment of glutamate metabolism. Gender differences were revealed in the reversal of GDH activity level after the therapy: in men, the level of GDH activity did not recover to control values after the treatment course. An elevation in the level of GDH to control values over a 28-day course of therapy occurred only in patients with RDD, but not in patients with BD.