IMPORTANT RESEARCH at Trinity College Dublin has opened up the possibility of new drug treatments that could halt progressive blindness.

The discovery, which helps specialised drugs penetrate through to their target tissues, may also prove valuable in neurological conditions such as Alzheimer's.

The work comes from the Smurfit Institute of Genetics' Ocular Genetics Unit. Dr Matthew Campbell led the research with Prof Peter Humphries and involved other Trinity colleagues.

They have developed a way to help drugs cross the "blood-retina barrier", the natural seal that keeps blood-borne substances away from the retina.

There is a similar blood-brain barrier that must be overcome to get useful drugs into brain tissues.Almost all of the drugs that look promising for the treatment of degenerative diseases of the retina including retinitis pigmentosa, age-related macular degeneration and retinal damage caused by diabetes cannot reach the retina because of the barrier, Dr Campbell said yesterday.

The new technique, however, temporarily opens up the blood-retina barrier. It uses small pieces of genetic material that temporarily interferes with the barrier and has successfully been shown to work with mice.

Only drugs that have a small molecular size are able to pass through, but unwanted things circulating in the blood such as antibodies or albumin are still kept out, Dr Campbell said.

It so happens that the molecular size of drugs that seem suited to these degenerative diseases is also small, allowing them to pass through the retinal barrier. It will allow rapid testing of drugs that might be useful in these diseases.

Importantly, the technology could also be adapted for use in neuro-degenerative conditions, Dr Campbell added. Diseases of interest in this case include Alzheimer's but also multiple sclerosis. It could also be of use to help drug delivery for untreatable brain tumours, he believes.