Macular degeneration robs millions of people of their sight, and now we know what triggers the inflammation that causes it. That raises the exciting possibility we can stop it.
Our Jayakrishna Ambati, MD, (at left in the picture) and Nagaraj Kerur, PhD, have identified a specific enzyme that triggers the immune system to go into overdrive in the “dry” form of macular degeneration, ultimately leading to the loss of key vision cells in the retina. Curiously, the enzyme is typically associated with the immune system’s response to viruses and bacteria, but neither is thought to be a factor in macular degeneration. That suggests a surprising new role for the enzyme.
The enzyme, cGAS, may be responsible for flagging up not just pathogens but other harmful problems that require the attention of the immune system. The enzyme also may be a player in conditions such as diabetes, obesity and lupus, and researchers already are working on drugs to block its effect. With such a drug, doctors might be able to halt the progress of macular degeneration (though this, if it pans out, is likely years away). Further, researchers may be able to test levels of the enzyme in the eye to determine the best time to administer treatment.
The discovery is very good news in the battle against macular degeneration. Clinical trials of potential new treatments have come to dead end after dead end in recent years, and this offers scientists an exciting new lead to pursue.