Serum brain-derived neurotrophic factor and macular perfusion in type 2 diabetes mellitus using optical coherence tomography angiography.

Purpose: To investigate the relationship between serum brain-derived neurotrophic factor (BDNF) and changes in macular perfusion in different stages of diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA).

Materials and methods: The study was conducted on 72 eyes of people with type 2 diabetes mellitus (DM). They were divided into five groups based on their DR stage: no DR (nDR), mild and moderate nonproliferative DR, severe nonproliferative DR, active proliferative DR (aPDR), and stable PDR. The presence or absence of diabetic maculopathy was also used to categorize the cases. All patients underwent a complete history, ophthalmological examination, OCTA imaging, and evaluation of BDNF and glycated hemoglobin A1c levels.

Results: The mean blood BDNF levels in the aPDR group were considerably lower than those in the nDR group (P = 0.023). In comparison to eyes without maculopathy, eyes with maculopathy had considerably decreased mean blood BDNF levels (P = 0.0004). Comparing NPDR and PDR groups to nDR as well as NPDR and PDR, a substantial decrease in average and parafoveal vessel density (VD) of the retina and choriocapillaries was seen (P = 0.02). The Foveal Avascular Zone (FAZ) acircularity index and VD were found to be significantly impacted by deteriorating DR (P = 0.001 and 0.017, respectively). It was discovered that there is a positive correlation between BDNF and the FAZ fractal dimension (P = 0.03). In diabetic eyes, there was a statistically favorable correlation between BDNF levels and best corrected visual acuity (P = 0.002). Furthermore, there was a negative relationship between DM duration and BDNF (P = 0.021).

Conclusion: Serum BDNF levels decreased with the progression of DR and in patients with maculopathy. BDNF was found to be related to macular perfusion, particularly in the fovea.