1. Neurodegenerative metabolites and neuroprotective strategies in diabetic retinopathy

Diabetic retinopathy is widely considered a neurodegenerative disease. A number of cellular and molecular studies showed that retinal neuronal cells are vulnerable to be damaged soon after diabetes. In addition, retinal function tests also confirmed functional deficit in diabetic retina early in diabetes indicating dysfunction of neuronal cells. Altered levels of diabetes induced neurodegenerative metabolites have been found to be implicated in initiating those damages. Those metabolites include increased levels of glucose, glutamate, branched chain amino acids and homocysteine and decreased levels of certain vitamins such as folic acid and vitamin-B12. These altered metabolites activate a number of metabolic pathways leading to increases in oxidative stress and decreases in neurotrophic support in the diabetic retina. In turn, they damage neurons in diabetic retina. In this chapter, we discuss those potential excitotoxic metabolites and possible therapeutic targets to protect neurons. By protecting retinal neuronal damage early in diabetic retina, retinal vessels can be regressed to ameliorate the progression of diabetic retinopathy, a leading cause of blindness worldwide. Correspondence/Reprint request: Dr. Mohammad Shamsul Ola, Department of Biochemistry, Faculty of Science, King Saud University, Riyadh 11415, Saudi Arabia E-mail: [email protected] or [email protected] Mohammad Shamsul Ola & Abdullah S. Alhomida 2