The relationship between klotho, neurotrophic factors (BDNF, NGF, GDNF), and cognitive functions in patients diagnosed with bipolar disorder

AIM: In our study, we aimed to investigate the relationship between levels of BDNF, NGF, GDNF, and klotho and cognitive functions in patients diagnosed with bipolar disorder during the remission period. MATERIALS AND METHODS: The study included 48 male patients diagnosed with bipolar disorder who were in remission and 48 healthy individuals. All participants completed a sociodemographic data form and underwent neuropsychiatric tests. Young Mania Rating Scale, Hamilton Depression Rating Scale, Brief Psychiatric Rating Scale, and Global Assessment of Functioning scale were administered only to the patient group. RESULTS: There was no difference detected in the levels of BDNF and GDNF among healthy volunteers, while a difference was found in the levels of NGF and klotho. There were significant differences in the Wechsler and Stroop test between patients and healthy volunteers. Regression analysis revealed a relationship between color-word reading duration and BDNF in the patient group. Positive correlations were found between NGF and duration of illness, age, and Wechsler performance at 40 minutes. In patients, a positive correlation was found between klotho and the number of incorrect responses on the Stroop test. Regression analysis showed that klotho was positively correlated with the duration and interference parameters of the Stroop test and negatively correlated with Wechsler performance at 40 minutes. A positive correlation was found between GDNF and the number of spontaneous corrections on the Stroop. CONCLUSION: In our study, levels of klotho and NGF were found to be higher in healthy controls. There was no difference between the two groups in terms of BDNF and GDNF levels. The cognitive functions of patients with bipolar disorder during remission were found to be worse compared to healthy volunteers. BDNF, GDNF, NGF, and klotho were associated with cognitive functions. Keywords: BDNF, bipolar disorder, GDNF, klotho, NGF