New drug shows promise in diabetic retinopathy

A pain relief drug (+)-pentazocine has been shown to restore retinal health in diabetic mice. It is now hoped that this action can be replicated in humans.

Drs Sylvia Smith and Alan Saul from Medical College of Georgia, USA, performed the original research on the eyes of mice and now they want to know if the drug has the potential to block the damage caused to the eye by diabetes.

Within the early stages of diabetes in mice the researchers found that the drug appeared to interrupt the first wave of cell destruction using the drug (+)-pentazocine. This drug is generally known for its pain relieving power but it also seems to work by reducing cell stress, which the researchers believe is key to the eye damage caused by diabetes. The researchers have evidence that oxidative stress increases the level that sigma receptors bind to BiP, a stress protein, and sigma receptors are believed to help cells manage stress.

"We know (+)-pentazocine binds to sigma receptors, but one of the things we don't know is if the binding blocks or promotes sigma receptor action," Dr Smith emphasized. In collaboration with Dr Eric Zorilla at the Scripps Research Institute in California, Dr Smith now has mice with sigma receptors deleted that will allow her to better determine their role and how the drug intervenes.

A new $1.5 million grant from the National Eye Institute will allow the scientists to test their theories and fully determine the way in which the drug works.