Researchers believe that a protein called angiopoeietin-like 4 (ANGPTL4) may play an important role in the development of diabetic retinopathy. Therefore, directing drugs that could target this protein may prove to be useful in preventing and treating preventing retinopathy-related blindness.
A healthy eye is essential for good vision. Diabetic retinopathy, one of the most common diabetic eye diseases, usually affects both the eyes and causes progressive damage to the retina.
AdvertisementDiabetic retinopathy is the leading cause of new cases of blindness. It is known to affect 40 to 45 percent of American diabetics. In this condition, the eye's regular blood vessels are taken over by abnormal, fragile vessels that leak into the eye thereby causing damage and subsequently blindness.
In its early stages, diabetic retinopathy can be prevented by controlling diabetes. However in the later stages, laser surgery or injection therapy is recommended to prevent further damage to the eyes.
A protein which has been recently identified, known as angiopoietin-like 4 (ANGPTL4), has been implicated to play an important role in the development of diabetic retinopathy. Researchers believe that since this protein is present in high levels in eyes of people with diabetic retinopathy, blocking it as well as another protein, known as vascular endothelial growth factor (VEGF), could possibly prevent retinopathy-related blindness. VEGF has been already identified as one of the proteins causing diabetic retinopathy. Researchers are also of the opinion that measurement of ANGPTL4 levels could also help diagnose and treat retinopathy at a much early stage.
Akrit Sodhi, Assistant Professor of Ophthalmology at the Johns Hopkins University School of Medicine in Baltimore explained that, although anti-VEGF drugs such as bevacizumab, ranibizumab and aflibercept, often slowed the onset of retinopathy, they were unable to stop it altogether. This suggested that there were other factors in the eye that played a role in retinopathy, in addition to VEGF, and their goal was to identify these other proteins.
A study was thus undertaken which had three group of participants. The first group of people had healthy eyes and no diabetes, the second group had diabetes but no retinopathy, and the third group had both diabetes and retinopathy.
When tested and as expected, study participants from the third group had higher levels of VEGF in their eyes. However, some had low VEGF levels. This led the researchers to believe that there must be another protein too which is responsible for causing the disease.
The team of researchers then performed few experiments on human cells and mice during which they discovered the protein ANGPTL4. The researchers found that study participants with diabetic retinopathy had consistently higher levels of ANGPTL4 as compared to the other two groups, regardless of their VEGF levels.
Sodhi further commented, "When we blocked this factor in fluid from patients with diabetic retinopathy, this was extremely effective for blocking the ability to promote blood vessel growth in tissue culture."
The results of the study was published in the journal Proceedings of the National Academy of Sciences (PNAS).
The researchers are further studying the role of ANGPTL4 in other conditions such as macular degeneration. They are also evaluating the development of drugs capable of blocking ANGPTL4.