Reduced Levels of Brain Derived Neurotrophic Factor (BDNF) in the Serum of Diabetic Retinopathy Patients and in the Retina of Diabetic Rats

Abstract

Diabetic retinopathy (DR) is widely recognized as a neurovascular disease. Retina, being a neuronal tissue of the eye, produces neurotrophic factors for its maintenance. However, diabetes dysregulates their levels and thereby may damage the retina. Among neurotrophins, brain derived neurotrophic factor (BDNF) is the most abundant in the retina. In this study, we investigated the level of BDNF in the serum of patients with DR and also in the serum and retina of streptozotocin-induced diabetic rats. The level of BDNF was significantly decreased in the serum of proliferative diabetic retinopathy patients as compared to that of non-diabetic healthy controls (25.5 ± 8.5-10.0 ± 8.1 ng/ml, p < 0.001) as well as compared to that of diabetic patients with no retinopathy (21.8 ± 4.7-10.0 ± 8.1 ng/ml, p < 0.001), as measured by ELISA techniques. The levels of BDNF in the serum and retina of diabetic rats were also significantly reduced compared to that of non-diabetic controls (p < 0.05). In addition, the expression level of tropomyosin-related kinase B (TrkB) was significantly decreased in diabetic rat retina compared to that of non-diabetic controls as determined by Western blotting technique. Caspase-3 activity was increased in diabetic rat retina after 3 weeks of diabetes and remained elevated until 10 weeks, which negatively correlated with the level of BDNF (r = -0.544, p = 0.013). Our results indicate that reduced levels of BDNF in diabetes may cause apoptosis and neurodegeneration early in diabetic retina, which may lead to neuro-vascular damage later in DR.

Exposure to As, Cd and Pb-mixture impairs myelin and axon development in rat brain, optic nerve and retina

“…Following an O.N. injury, the brain-derived neurotrophic factor (BDNF) provides protection to the RGC (Chen and Weber, 2002), via pro-survival and anti-apoptotic mechanisms (Cellerino and Maffei, 1996;Ola et al, 2013).…”

Pathogenesis of Type 2 Diabetic Retinopathy by the Epigenetic Modification of 5-Carboxylcytosine DNA Methylation in the CpG Island of Promoter Region of Brain Derived Neurotrophic Factor

“…The level of BDNF in diabetic serum was modestly reduced to 15 % compared to that in nondiabetic control; however, the difference was not significant (p = 0.38). 37 Serum levels of BDNF in control, diabetic, and PDR patients were measured by ELISA kit. To the level from nondiabetic controls (n = 19) and early diabetic patients (n = 22) Reduced levels of BDNF in PDR groups (n = 47) were compared.…”

“…Values are mean ± SD, *#p\0.001 compared with control and diabetic. [37] Figure 9. BDNF serum concentration in healthy controls, diabetic patients, and PDR patients.…”

“…BDNF serum concentration in healthy controls, diabetic patients, and PDR patients. [37] Conclusions Epigenetic mechanisms play an important role in the case of Type 2 Diabetic Retinopathy because they provide a mechanism for continued altered gene expression. It has been noted that hyperglycemia can induce site-specific DNA methylation.…”

Biochemical Studies of Hippocampal Gene Expression of Brain-Derived Neurotropic Factor and Toll-Like Receptor-4 in Diabetic Rats Exposed to Chronic Stress: Effects of Antidepressant Drugs

“…Brain-derived neurotrophic factor (BDNF), an important neurotrophic factor exerting neuroprotective effects [8], has drawn attention as a pivotal player in the pathogenesis of depression [9] showed decreased levels in serum of diabetic patients and animals, and this was associated with a higher rate of complications [10]. Collectively, the decreased BDNF may be involved in the pathogenesis of both depression and DM [11].…”