United States researchers have identified a possible topical treatment for both wet and dry age-related macular degeneration (AMD) in a study that shows promise for clinical use.
The research finding from Boston’s Tufts University is the first to report successful topical use of a compound capable of inhibiting symptoms associated with both dry AMD (the earlier form) and wet AMD (the rarer, later form) and could represent a breakthrough for treatment of these conditions.
AMD is among the leading causes of blindness among the elderly. There is currently no treatment for dry AMD and wet AMD can only be treated with regular injections into the eye.
The development of a topical eye-drop treatment that works in both dry and wet AMD could increase treatment adherence and reduce patient discomfort by reducing or removing the need for direct injections.
The Tufts University team reported in their “proof of concept” study on mice that topical application of a compound called PPADS (pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid) inhibits damage to the tissues in the eye that impacts the individual’s ability to see colour and fine detail.
Senior study author, Associate Professor Rajendra Kumar-Singh, said the ultimate aim is to develop a therapy that can be self-administered daily, however further studies are required before moving to clinical trials.
To test the effectiveness of a topical application of PPADS, researchers induced the tissue damage and blood vessel growth characteristics of AMD in anaesthetised mice. The topical treatment was then administered every 24 hours for three consecutive days. The researchers assessed the eye tissues one week later for progression of the damage and blood vessel growth.
“Our study found that topical application of the PPADS compound… stops the damage to eyes caused by pores formed in the membrane that leads to cell death within the eye by stopping an immune system process known as complement that is responsible for dry AMD.
“Second, it prevents the formation of the blood vessels that can leak and damage the eye, a process associated with wet AMD,” explained first author Dr. Kerstin Birke, a postdoctoral scholar at Tufts.
The study was published in the open-access, peer-reviewed online journal: www.plosone.org
