Plugging Blood Vessels to Save Vision
The growth of malformed blood vessels that can burst is a leading cause of vision loss in North America. Retinopathy and retina degeneration are associated with premature birth, with diabetes, and with increasing age. Now a new drug approach has been developed by a research team led by Dr. Andras Nagy at the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital in Toronto for safer clean-up of deformed blood vessels in the eye. The study was published in May 2014 in EMBO Molecular Medicine.
The researchers showe both safety and effectiveness in their bioengineered compound when treating retinopathy in mice. The therapeutic, which they called "Sticky-trap," shuts down tiny deformed blood vessels in the eye without affecting healthy vessels in other sites of the body. An editorial accompanying the atrticle stated that the compound "holds great promise as a strategy that could be rapidly translated into clinical practice. […] We expect that Sticky-trap and future related molecules will have significant impact on the field of tumor biology in local control of recurrent disease. […]"
Dr. Nagy is a Senior Investigator at the Lunenfeld-Tanenbaum and holds a Canada Research Chair in Stem Cells and Regeneration. He is a Professor in the Department of Obstetrics and Gynacology at University of Toronto and an Investigator at the McEwen Centre for Regenerative Medicine. Co-authors include colleagues from University of California Los Angeles, The Scripps Research Institute (La Jolla CA), University of Toronto, and the Lunenfeld-Tanenbaum.
Selective action is key to safety
Like some other treatments for retinopathy, Sticky-trap is injected into the eye. The potential game-changer is Sticky-trap's safety profile. It is stable and long-lasting once in the eye. If the compound gets into the circulation, it quickly inactivates – ensuring that it does not affect other blood vessels, tissues, and organs.
A problem in this research arena – called antiangiogenesis – has been finding a compound that is selective, closing off abnormal blood vessels only in the diseased organ while leaving all others intact. "That's difficult, and it's what makes this research high-risk as well as high-impact," Dr. Nagy says.
Type 2 diabetes illustrates the challenge. "Patients with diabetic retinopathy are losing vision because blood vessels in their eyes overgrow, become deformed and burst, often tearing the retina in the process. Drugs that suppress the excess vessel formation in the eye could negatively affect healthy organs if they escape into the blood, causing kidney function problems, poor wound healing, and hypertension," Dr. Nagy adds. These side effects are serious health threats that the Sticky-trap approach can avoid.