Soy isoflavone may have potential as therapy for early diabetic retinopathy

NEW YORK — A nutritional supplement extracted from soybeans may potentially help delay early progression of diabetic retinopathy, laboratory testing suggests.

Where most therapies focus on advanced stages of diabetic retinopathy, the isoflavone genistein could help prevent early disease progression, said Mike Cooney, MD, who described experimental work with the compound here at Macula 2006.

“Nutritional supplements for diabetic retinopathy must focus on the compound that focuses on oxidative stress,” he told attendees.

Dr. Cooney said genistein has good bioavailability and a good safety profile. It works as a strong antioxidant as well as an inhibitor of aldose reductase, the enzyme that changes glucose into sorbitol, a sugar alcohol that can lead to retinopathy and neuropathy in large quantities, he said.

In experimental ischemia studies, genistein was shown to inhibit protein tyrosine kinase pathways and to provide neuroretinal protection, Dr. Cooney said.

He said it also has been shown to reduce activated vascular endothelial growth factor receptors.

The potential benefits of genistein could have a “major public health impact,” he said.