Following experiments on diabetic mice, the researchers found there were a lot of white blood cells infiltrating the retinal vessels, said Arup Das, chief of the Division of Ophthalmology in the UNM Department of Surgery. The researchers think the molecules they found during their experiments on animals could also be found in humans.
The drugs that are presently used for treatment of blood leakage in the eyes are called anti-VEGF drugs that are directly injected into the eye, Das said.
“We are finding that these drugs are not really effective and are targeting a particular molecule,” Das said. “We are trying to find out other molecules that are responsible for the disease and could be targeted.”
Diabetes is a global issue. The number of cases is increasing throughout the world, according a World Health Organization report. The United States is third on the list of countries with the highest rates of diabetes, according to WHO officials.
Twelve percent of new blindness cases reported every year in the United States are the result of diabetes, Das said. New Mexico has 150,000 diabetics, and 50,000 of them may develop the eye disease, he said.
“All these diabetic people have complications in the eyes. Their retinal vessels are damaged and leaked,” he said. “It is a leading cause of blindness in the middle-aged people in this country.”
The researchers are examining what causes inflammation and the breaking down of the blood, said Carolina Franco Nitta, a postdoctoral research scholar working under Das’ supervision
“What we look at, actually, is patients that have diabetes,” she said. “What ultimately ends up happening is that the blood vessels they have in their eyes become leaky with the incidence of diabetes. We as investigators are trying to stop that from happening before it starts, or even try to reset it back to the normal.”
There are two main cell types important in vasculature and human eyes, she said: endothelial cells and pericytes.
“Endothelial cells are kind of like tubing that you have in your house. The tubes have to fit next to each other so that you maintain that integrity of those,” she said. “The pericytes are those cells that kind of wrap around those endothelial cells, and they kind of hug them and hold them really close.”
Without those two cells, the vessels in the eyes do not maintain rhythm and patients get blood leaking from inside the vessels to the retina, she said.
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The researchers are looking at a molecule called S1P that is created by pericytes.
“This molecule is actually responsible for maintaining the connection between cells,” Nitta said. “If you lose that molecule, then the cells that wrap around endothelial cells actually get lost. If you lose those cells, you get leakiness.”
The researchers have been able to identify that diabetic patients have less of that SIP molecule, and now they are trying to investigate whether they can target that molecule and produce more of it to reverse leakiness, she said.
The research team includes both researchers and clinicians, Nitta said.
“Das understands all aspects of how research goes,” she said. “We try to connect what we do in the laboratory and what he observes in the clinic. He knows what the end-point diseases are and what bothers patients more. So we try to get anything that is in the laboratory to kind of meet those requirements.”
Sayyed Shah is the interim news editor at the Daily Lobo. He can be contacted at news@dailylobo.com or on Twitter @mianfawadshah.
