A daily dosage of a low concentration of aspirin may inhibit diabetic retinopathy, according to new research in the December issue of Diabetes.1

A research team, led by ophthalmologist Mara Lorenzi of the Schepens Eye Research Institute at Harvard Medical School, compared the impact of clopidogrel, a selective anti-platelet drug, with the effect of aspirin in rats with streptozotocin-induced diabetes. The researchers reported that clopidogrel did not prevent neuronal apoptosis, glial reactivity, capillary cell apoptosis or acellular capillaries in the retinas of diabetic rats. However, aspirin at doses far below the anti-inflammatory range for humans did prevent apoptosis of capillary cells and the development of acellular capillaries, but did not prevent neuroglial abnormalities.

Before aspirin can be recommended to help prevent diabetic retinopathy, though, further research must determine which minimal dose is effective and which processes it targets in the retinal vessels, Dr. Lorenzi says.

It will become great therapy if effective at small doses so as to be safe for chronic use, she says. I expect that it will be mostly effective when taken to prevent retinopathy. It is unlikely to help much if retinopathy is already advanced.

 The American Diabetes Association already recommends an anti-platelet dose of aspirin (81mg per day) to people who have diabetes for prevention of cardiovascular disease when they have one additional risk factor. Dr. Lorenzi said she hopes that patients follow this official recommendation.

Be assured that we are working hard to make available soon some drug that can be given safely to patients to limit the damaging effects of high blood glucose and help prevent retinopathy, she says.

This study seems to refute earlier research. Previous studies on the use of aspirin in diabetic retinopathy showed that aspirin alone or in combination with dipyridamole neither lowered nor increased the risk of developing diabetic retinopathy.2

1. Sun W, Gerhardinger C, Dagher Z, et al. Aspirin at low-intermediate concentrations protects retinal vessels in experimental diabetic retinopathy through non-platelet-mediated effects. Diabetes 2005 Dec;54(12):3418-26.

2. Bergerhoff K, Clar C, Richter B. Aspirin in diabetic retinopathy. A systematic review. Endocrinol Metab Clin North Am 2002 Sep;31(3):779-93. Review.

Vol. No: 143:02Issue: 2/15/2006