Brain-derived neurotrophic factor in age-related macular degeneration.

Age-related Macular Degeneration (AMD) is a leading cause of vision loss. There is no cure for AMD. Current treatments focus on preventing disease progression and preserving vision. In recent years, the role of brain-derived neurotrophic factor (BDNF) in AMD has attracted increasing attention. BDNF is widely involved in the physiology and pathophysiology of the retina. These include the development of photoreceptors during early development and synaptic communication between photoreceptors and retinal neurons. Under pathological conditions, BDNF affects the functions of multiple cell types in the retina including photoreceptors, ganglion cells, Müller cells, microglia cells, amacrine cells, and the retinal pigment epithelium (RPE). Importantly, BDNF does not act alone. Its function relates with other neurotrophic factors such as basic fibroblast growth factor (bFGF), ciliary neurotrophic factor (CNTF), and glial cell derived neurotrophic factor (GDNF). Meanwhile, the dynamic interaction between BDNF, its precursor protein proBDNF and the BDNF receptor TrkB not only affects the survival of retinal cells in AMD but may also guide the treatment strategy. Various approaches have been taken to deliver BDNF in animal models for managing AMD. Despite the exciting progress, challenges remain in implementing BDNF therapy as an effective treatment. In this review, we summarize the current research progress of BDNF in AMD and highlight the issues that need to be addressed before translation into clinical practice.