Diabetic retinopathy and its relation to serum brain-derived neurotrophic factor level.

Diabetes mellitus (DM) is a metabolic disorder of the proteins, lipids, and carbohydrates, results in hyperglycemia. Abnormalities in the function of insulin on target cells, its release from beta cells, or both may contribute to DM. The purpose of this research was to assess the progression of diabetic retinopathy (DR) to the levels of serum brain-derived neurotrophic factor (BDNF), glycated hemoglobin (HbA1c), and biochemical parameters. The study included 44 normal control subjects, 44 diabetic participants, who were separated into four groups based on their diabetes status and the results of fundoscopic examination. A commercial enzyme-linked immunosorbent assay kit was used to measure the levels of BDNF in the serum. The analysis revealed that diabetics had significantly lower serum BDNF levels than non-diabetics (p < 0.001). Also, there was a significant reduction in BDNF levels with the development of proliferative diabetic retinopathy in comparison with diabetics without DR (p < 0.001). In conclusion, serum BDNF levels decreased significantly in diabetics with and without DR compared to apparently healthy individuals, as well as with the progression of DR.