Novel biomarker looks for diabetic retinopathy

A targeted molecular imaging technique could aid in the prevention of blindness associated with progressive diabetic neuropathy by tracking alterations in the retinal endothelium, the Federation of American Societies for Experimental Biology (FASEB) announced yesterday.

Ali Hafezi-Moghadam, MD, PhD, a researcher from the Center for Excellence in Functional and Molecular Imaging at Brigham and Women's Hospital and Harvard Medical School in Boston, Mass., and colleagues have been developing an optical technique that can detect subtle changes in the retinal tissues before irreparable changes have taken hold.

"My goal is to establish a versatile clinical tool that alerts of a disease process right when the first molecular changes take place,” said Hafezi-Moghadam in the FASEB statement. “This will then provide ample opportunity to act, as opposed to merely acknowledge that there is structural damage that we cannot do anything about."

The researchers are focusing specifically on higher vascular endothelial growth factor receptor 2 (VEGFR-2) expression in the retinal capillaries of patients as a diagnostic biomarker for diabetes. Hafezi-Moghadam et al published their findings in the September 2014 journal of the FASEB.

For this preclinical study, researchers developed investigational molecular agents that target the overexpression of VEGFR-2 on the intraluminal surface of retinal vessels of diabetics. Vascular endothelial growth factor-A (VEGF-A) was injected and found to spread in diabetic models as shown by fluorophore binding.

Results indicated, contrary to what one might think, that overexpression is particularly apparent in the micro-vessels and not major vessels when compared to healthy controls. The authors wrote that their was 94 percent higher accumulation of their agents locking to VEGFR-2 in the retinal and choroidal vessels of diabetic animals when compared to healthy ones. In fact, more than 80 percent of the VEGFR-2 in the retinas of diabetic models was found in the capillaries. This was compared to only 47 percent VEGFR-2 in the capillaries of normal controls.

This study provides quantifiable evidence of the progression of diabetic retinopathy, but the implications of the research could apply to the imaging of other diseases. “Here, we have shown it in an important disease, the diabetic retinopathy, but there is no reason to stop there," said Hafezi-Moghadam.