New research reveals that a gene called Robo4 could help
curb or prevent two leading causes of blindness: age-related macular
degeneration (AMD) and diabetic retinopathy.
AMD is a medical condition that affects mostly the elderly
and in which the center of the lining of the eye, known as the macula area of
the retina suffers thinning, atrophy, and in some cases, bleeding. This can
result in loss of central vision, which entails inability to see fine details,
to read, or to recognize faces.
According to the American
Academy of Ophthalmology, AMD is the
leading cause of central vision loss (blindness) in the U.S. today for
those over the age of fifty years, effecting more than 10 million individuals.
Diabetic retinopathy caused by complications of diabetes
mellitus can also lead to blindness. The disease affects up to 80 percent of
all diabetics who have had diabetes for 10 years or more.
The University
of Utah study suggests a
new therapeutic target for these two ophthalmic diseases, as well as other
conditions marked by inflammation and vascular leakiness, including cancer and
certain traumatic injuries.
“Many diseases are caused by injury or inflammation destabilizing
blood vessels and causing them to leak fluid into adjacent tissues as well. We
found a natural pathway – the Robo4 pathway – that counterattacks this by
stabilizing blood vessels. Robo4 tells the vessels not to grow, to stabilize, not
to explore. The blood vessels have an instruction system that tells them to do
the opposite, to stabilize,” study senior author Dr. Dean Li of the University
of Utah School of Medicine in Salt
Lake City said, according to the Telegraph.co.uk.
Dr. Li, along with Dr. Kang Zhang, also of the University of Utah, mutated the Robo4 gene in mice. Activating
the Robo4 gene shored up leaky blood vessels and curbed the development of new
blood vessels, Dr. Zhang found in a series of experiments in test tubes and
mice.
To do that, the Robo4 gene countered a chemical called
vascular endothelial growth factor (VEGF), which signals the creation of new
blood vessels. This way, Robo4 prevented VEGF from issuing the “let’s make some
blood vessels” order.
The Robo4 gene not only stopped the uncontrolled growth of
the weak and leaky eye vessels, it also reversed the vessel damage. Dr. Li said
clinical trials on human would probably take place within the next 5 year.
Dr. Randall Olson, director of the John
A. Moran
Eye Center
at the University of Utah, welcomed the University of Utah
study, calling Dr. Li’s findings historic.
“This is a major breakthrough in an area where the advances
have been minimal. We are excited about taking this opening and moving the
frontier forward with real hope for patients who have but few, often
disappointing, options,” Dr. Olson said.
The study was published in the March 16 online edition of Nature Medicine.