Title:Brain-derived Neurotrophic Factor Level and Gene Polymorphism as Risk Factors for Depression in Patients with type 2 Diabetes Mellitus- A Case-Controlled Study
Volume: 21
Issue: 4
Author(s): Hany Hammad, Inass Shaltout, Mai M. Fawzy, Laila A. Rashed, Noha Adel and Tarek S. Abdelaziz*
Affiliation:
- Internal Medicine Department, Faculty of Medicine, Cairo University, Cairo, Egypt
Keywords:
Brain-derived neurotrophic factor, nerve growth factors, diabetes mellitus, type 2, depression, depressive disorder.
Abstract:
Background: Diabetes mellitus and depression are comorbidities that can be caused
by each other. Brain-derived neurotrophic factor (BDNF) functions as a neuronal growth factor.
It maintains the functional integrity of the nervous system.
Aim: To study the possible association between BDNF levels and gene polymorphism with depression
in patients diagnosed with type 2 diabetes mellitus.
Methods: The Elisa technique measured BDNF, and rs6265 gene polymorphism was detected
using real-time PCR. Depression was assessed utilizing a clinical interview tool designed to establish
the diagnosis of depression and differentiate it from other psychiatric diseases.
Results: BDNF levels were significantly lower in patients with type 2 diabetes mellitus and
symptoms of depression than in patients with type 2 diabetes mellitus and no symptoms of depression
(82.6±16.1. vs. 122± 17.47, P< 0.001). There was a statistically significant difference
in BDNF levels in patients with diabetes among the three genotypes of the BDNF gene (P-value
< 0.001). Val/ Val carriers had the highest serum BDNF levels, and Met/ Met carriers had the
lowest serum BDNF levels. Subgroup analysis showed statistically significant genotype-related
differences in serum BDNF levels among the three subgroups in the Depression group. Val/ Val
carriers had the highest serum BDNF levels, and Met/ Met carriers had the lowest serum BDNF
levels. BDNF Val66Met polymorphism had no significant association with the presence of depression,
yet there was a trend towards significance (p = 0.05).
Conclusion: In this pilot, Low levels of BDNF were associated with depression in patients with
type 2 diabetes. Carriers of the Met/ Met allele have the lowest serum BDNF levels. Multicenter
studies with more participants are required.
