Eye-catching discoveries

 

Current medical research runs the gamut from lab-grown eye tissue to clever tricks with bugs, writes CLAIRE O'CONNELL

HOW DO you grow eye tissue in the lab to help restore sight after damage? Can you use tricks from “bad” bugs to do good things in the body? And what do stiff arteries and wrinkles have in common?

These are some of the questions discussed in this year’s Picture of Health report from the Health Research Board, an annual snapshot that highlights some of the projects it has recently funded.

This year’s crop covers a spectrum of research approaches, from digging into the causes of disease, through bringing discoveries closer to the clinic and analysing the experience of staff and patients.

One of the most eye-catching projects, literally, is research on how to grow eye tissue in the lab that could help people who have suffered severe damage to the cornea, the clear dome that covers the pupil.

“The cornea is the window that lets light into the sensory organs at the back of the eye,” says researcher Dr Finbarr O’Sullivan from the National Institute for Cellular Biotechnology at Dublin City University.

That clear “pane” also acts as a barrier to protect the eye, and does a big chunk of the focusing, he explains.

If the cornea gets severely damaged – perhaps because of a medical problem or an accident like burning or a chemical splash – its replenishing stem cells can be killed and the white of the eye can grow over it: “That means the person is not going to see through that eye, and it can be irritating and painful,” says O’Sulllivan. Some patients can benefit from a direct transplant of donor tissue from the “limbus”, the portion of the cornea that makes the stem cells.

But that doesn’t work for everyone, so the team at DCU has been working with the Royal Victoria Eye Ear Hospital and the Irish Blood Transfusion Service laboratories to develop a method to grow ready-made sheets of cells in the lab for transplant.

The approach is to build the corneal sheets to order, starting initially with donor tissue, in a process that takes about 20 days, explains O’Sullivan. Thanks to getting an understanding of how the cells work and behave in culture, they now have an optimised protocol for growing them in the lab, and he believes clinical trials in patients here will start next year.

From growing parts of eyes to clever tricks with bugs: another project has been looking to pilfer tricks from disease-causing bacteria and use them to soup up “good” probiotic bacteria so they can survive longer in the gut.

We hear a lot about the benefits of some probiotics, but sometimes they don’t hang around a long time in the intestine, explains Dr Roy Sleator, a lecturer at Cork Institute of Technology.

While at University College Cork, he worked on a project funded by the Health Research Board to engineer better “good” bugs by borrowing from the tricks of hardy survivors that might not be so welcome in our guts.

“We identified some genes that allow certain disease-causing bacteria, or pathogens, to survive against the innate defences of the stomach acid and intestinal bile,” he explains.

“Then we used those genes to ‘upgrade’ the good probiotics, and we found that probiotics expressing the pathogen’s genes could survive for longer in the gut, where the probiotics continued to be beneficial.”

But we are not likely to be wolfing down any such upgraded bugs as a matter of course, notes Sleator.

“In the near future or the medium term, these will not be used on off-the-shelf products,” he says “We see them instead as being delivery platforms for vaccines or drugs.”

Another Health Research Board project has raised the profile of a type of gnarly molecule that could be the target of future drugs for high blood pressure.

Called advanced glycation end-products (appropriately shortened to AGEs) these are complexes of carbohydrates, proteins and cross-linked collagen that crop up in wrinkles, cataracts and now stiff arteries, according to Dr Azra Mahmud.

Her work with the late Prof John Feely at St James’s Hospital looked at how levels of AGEs in the bloodstream compared with the degree of artery stiffness in patients who were going for bypass surgery.

What they saw was that increased stiffness was linked with higher levels of AGEs.

The findings could help inform new approaches to tackling arterial stiffness and related conditions such as high blood pressure, says Mahmud.

Picture of Health 2011 is available at hrb.ie. Claire O’Connell is one of the report’s co-authors