Trinity Researchers Develop New Drug Delivery System for Retinal Disease

Researchers at the Smurfit Institute of Genetics’ Ocular Genetics Unit at Trinity College Dublin have reported the development of a new drug delivery system which has the potential to treat degenerative diseases of the retina, including retinitis pigmentosa, age-related macular degeneration and diabetic retinopathy, conditions which collectively represent the most prevalent causes of registered visual handicap in developed countries. The research was led by Dr Matthew Campbell and Professor Peter Humphries of TCD’s Smurfit Institute of Genetics and School of Genetics and Microbiology.

Currently an estimated 98% of clinically validated drugs, many of which would have utility in the treatment of these diseases, can not cross from the bloodstream into the retina because of the presence of the so-called inner blood-retina barrier, which, as its name implies, represents a tight seal between the blood-supply and retinal tissues. The researchers at Trinity have developed a method for periodically and reversibly opening the barrier in mice (mice have a similar barrier to humans) to very small molecules – just enough to allow therapeutic drugs into the eye, but small enough to keep harmful blood-born substances out.

The new process, the development of which has been supported by the Wellcome Trust, Science Foundation Ireland and Fighting Blindness Ireland, and which will shortly be reported in the international journal, Proceedings of the National Academy of Sciences (USA), has been used by the researchers to radically improve vision in mice modeling one form of the hereditary retinal disease, retinitis pigmentosa and it has also been used in the suppression of new retinal blood vessel growth in mice, a phenomenon called neovascularisation, which is the major sight-threatening symptom associated with age-related macular degeneration in humans. The researchers are optimistic that this novel method of drug delivery will be translatable into processes for human therapy targeting not only diseases of the retina but potentially also those causing degeneration of the brain for which there is a similar blood-brain barrier.

Commenting on the significance of the research Dr. Matthew Campbell stated: “Enhanced drug delivery to the retina has the potential to treat the hereditary retinal disorder retinitis pigmentosa as well as the common degenerative retinal condition age-related macular degeneration. There may also be applications for its use in glaucoma and diabetic retinopathy. In a broader sense however, aspects of this technology could be adapted for a range of neuro-degenerative conditions including Alzheimer's disease and multiple sclerosis, while also potentially allowing for enhanced drug delivery to un-treatable brain tumours.”