News & Events
Elizabeth R. Gaillard, Ph.D.
Posted on April 7, 2017
Date - April 7, 2017
Professor and Director Center for Biochemical and Biophysical Studies
Department of Chemistry and Biochemistry
Northern Illinois University
Title: “Photomodulation of the inflammatory response by human ocular melanin”
The human retina is under extensive photooxidative stress from locally high partial pressures of oxygen and continuous exposure of the tissue to ambient radiation. The leading cause of blindness in developed nations among persons over the age of 70 is age related macular degeneration. This disease has been strongly correlated with exposure to visible light, particularly the short wavelength portion of the visible spectrum, and reduced levels of pigmentation associated with ethnicity. Melanin is the heterogeneous polymer responsible for pigmentation in mammals and for photoprotection of the retina. It has been reported that the amount of ocular melanin and therefore the extent of photoprotection decreases with age and this is attributed to photoxidative damage to the melanin polymer. We observe that melanin from young mammals affords protection to ocular retinal pigment epithelial cells from reactive oxygen species (1.7 times) after exposure to UVB radiation but exhibits greater protection (2.4 times) after exposure to the blue light portion of the visible spectrum. When RPE cells are pigmented with ocular melanin from older >70 years human donors, photoprotection is lost and photoxidative damage is observed. This evidence suggests melanin may play a role in ocular inflammatory response and that oxidative damage to this polymer with age results in proinflammatory behavior.