Age related macular degeneration (AMD) is the leading cause of vision loss in persons over the age of 50. If the person has the “wet” variety, treatments include anti–vascular endothelial growth factor (VEGF) drugs that are injected into the eye and laser treatments. The trouble comes when a person has AMD that is resistant to treatment. There aren’t many options that preserve vision. Of course, research is taking place that points to possible treatments for those whose AMD is resistant to treatment. One has to do with a way to preventing scars and other has to do with using a protein to overcome anti-VEGF resistance.
Research done at the Moran Eye Center at the University of Utah shows how cholesterol isn’t just bad for your arteries. It is also bad for vision. The good news is that it can be a target for treatment.
A cholesterol known as oxysterol 7-ketocholesterol (7KC) builds up in a person as he or she ages. It also builds up in the Bruch’s membrane and in persons with AMD. Researchers found in the eyes of mice that 7KC can change the choroidal endothelial cells and they in turn invade the neural retina and this leads to fibrosis or scarring. The changed choroidal endothelial cells may be less responsive to anti-VEGF drugs, which may explain why these drugs stop working in those who utilize them to treat wet AMD. The findings from this research suggest that if there is a way to stop the formation of fibrosis, then there will be an improvement of outcomes in wet AMD patients who use anti-VEGF drugs.
Protein to the Rescue
Researchers at Baylor College of Medicine and Houston Methodist found a strategy that may overcome the problem of anti-VEGF resistance. Working with mice, the researchers discovered when they combined a protein known as apolipoprotein A-I binding protein (AIBP) with anti-VEGF drug, the anti-VEGF resistance is reduced and choroidal neovascularization (CNV), an aggressive form of age-related macular degeneration is suppressed.
If that isn’t good enough, scientists found that the AIBP also leads to the removal of cholesterol from the choroidal endothelial cells. In fact, the inspiration for this study came from other studies that suggested that increased cholesterol accumulation leads to CNV. Since AMD has many things that contribute to its development, treatments need to target diverse pathways in order to have positive outcomes.
“Together, these observations suggested the possibility that AIBP might help overcome anti-VEGF resistance and effectively suppress CNV,” said Dr. Yingbin Fu, the co-corresponding author of the study and associate professor and Sarah Campbell Blaffer Endowed Chair of Ophthalmology at Baylor University.
Once again research is pointing the way to possible treatments for AMD. As a result, one day people won’t have to dread becoming blind because there are treatments that will lead to better outcomes.