Prolidase activity and its diagnostic performance in bipolar disorder

Proline has an important role in the brain. Prolidase, a proline splitting enzyme, which is also involved in oxidative stress is not investigated in bipolar disorder (BD).

66 BD type I patients and 66 healthy controls were enrolled. Serum prolidase activity was measured in both groups via venous sampling. We have compared patients and controls as well as 3 subgroups of patients (24 euthymic, 22 manic, and 20 depressive patients).

Prolidase activity was significantly higher in patients (p<0.001, t=14.517). There wasn't any significant difference among euthymic, manic and depressives (p=0.305, f=1.211). Positive predictive value was 98.5% and negative predictive value was 92.4% above the cutoff point 502.9375U/L of prolidase activity.

Prolidase activity is impaired in BD, which may be associated with oxidative stress. Prolidase activity may be a trait marker for diagnosing bipolar disorder.