Background: BDNF is a neuronal growth factor essential for nervous system maintenance.
Objective: We have evaluated peripheral neuropathy (PN) and depression in patients with type 2 diabetic mellitus and looked for an association with serum protein levels of BDNF and the BDNF-Val66Met-SNP.
Methods: Symptoms of PN were clinically assessed and graded using Total Neuropathy Score (TNSr) scale. Small nerve fiber testing was performed using the Q-sense device. Depression was assessed using PHQ9 questionnaire. BDNF protein levels and Val66Met-SNP were determined with ELISA and Sanger sequencing respectively.
Results: 42 patients, 18 non-insulin treated (NIT) and 24 insulin treated (IT) were included. Albeit similar disease duration, the IT group show increased HbA1c and glucose levels as compared to NIT group, suggesting a more aggressive disease in the IT group. Higher TNSr-sensory and autonomic scores and low sensitivity thresholds to cold, warm and hot-pain signals were found in the IT group. Likewise, PHQ9 score was higher in the IT group. Serum BDNF protein levels were lower in the IT group. Met-BDNF proportion among female patients was lower relative to male patients (23.5% vs. 76.5% respectively, Prob>ChiSq=0.01). Of note, Met-BDNF female patients were all in the IT group and show a trend of increased TNSr and PHQ9 score as compared to Val-BDNF female patients. Correlations between patients' PHQ9 score and TNSr score or Q-sense cold and warm sensitivity thresholds were found only in Met-BDNF carriers, suggesting that PN and depression are coincided in Met-BDNF carriers.
Conclusion: A diminished peripheral BDNF resource in our IT patients is associated with uncontrol diabetes and underlined augmented symptoms of PN and depression. The negative effect of Met-BDNF in female patients and the correlation of depression and PN in Met-BDNF should be further studied.
A. Bashkin: None. A. Safadi: None. B. Gross: None. N.A. Horowitz: None. R. Sharon: None. E. Shaoul: None. M. Nodelman: None. D. Azoulay: None.