April 7, 2006
Omega-3 fatty acid involved in eye retina protection

In an article published online on April 3 2006 in the journal Trends in Neuroscience, Nicolas G. Bazan, MD, PhD, describes his discovery of a protective role for the omega-3- fatty acid docosahexaenoic acid (DHA) against degenerative diseases of the retina. In these diseases, which include age-related macular degeneration and retinitis pigmentosa, photoreceptor cells degenerate and die, leading to vision loss.

Dr Bazan, who is the Director of the Neuroscience Center of Excellence at Louisiana State University Health Sciences Center in New Orleans, in collaboration with researchers at Harvard University, found that DHA in retinal pigment epithelial cells is a precursor to a compound called neuroprotectin D1, which is synthesized by the cells as part of a response to oxidative stress, sunlight, or trauma. Retinal pigment epithelial cells are responsible for maintaining the photoreceptor cells that degenerate in retinal diseases, as well as regulating the delivery of DHA to these cells. Neuroprotectin D1 prevents genes which cause inflammation and cell death from being switched on by oxidative stress and other factors, consequently promoting the survival of the retinal pigment epithelial cells. The compound as well as its precursor DHA also reduce free radical production. In addition, DHA facilitates the expression of proteins that promote protective cell signaling.

Dr Bazan has found that DHA also promotes survival and inhibits cell death in neurons in a model of Alzheimer's disease.

"Because the early clinical manifestations of most retinal degeneration precedes massive photoreceptor cell death, it is important to define the initial crucial events," Dr. Bazan observed. "This knowledge might be applicable to the design of novel therapeutic interventions to halt or slow disease progression."