Extra: The Irish scientists tackling organ transplant rejection

We were delighted to see our Chief Investigator, Professor Roisin Dolan, join Jonathan McCrea on Future Proof Extra this week for an in-depth conversation about organ transplant rejection and the work we are doing here at Sentinel Study Ireland. The episode, titled "The Irish scientists tackling organ transplant rejection" gave a national audience a clear and accessible look at why this research matters — and what we hope it can achieve for transplant patients in Ireland and beyond.

Jonathan opened by reflecting on two landmark moments in transplant history: the world's first human heart transplant in 1967, and the first successful combined heart-liver transplant in 1984. Both patients, as Roisin explained, ultimately died from complications related to rejection. The science has come a long way since then, but rejection remains one of the most serious challenges in transplant medicine today. Managing it requires a delicate balance: immunosuppressant drugs must be strong enough to prevent the immune system from attacking the new organ, but not so strong that they cause serious side effects — including infections, cancers, kidney failure, and diabetes. Getting the dose right is difficult, and diagnosing rejection early is harder still, given that its symptoms can be vague and easily confused with viral infection.

This is the problem our study is designed to address. The concept behind the Sentinel Study originated at Oxford, where plastic surgeon Professor Henk observed that a patch of donor skin transplanted alongside internal organs displayed visible signs of rejection — redness and swelling on the surface — several days before rejection appeared in the organs themselves. The skin was acting as a sentinel: an early, visible warning.

Roisin has brought this idea to Ireland in a refined form. In our study, a small patch of donor skin — around ten by three centimetres — is microsurgically connected to the recipient's blood supply and placed on the forearm or upper arm. Because it shares the recipient's circulation, it responds to the same immune signals as the transplanted organ, but makes those signals visible on the surface of the body. Patients can check it themselves each morning.

We spent the first six months of the study co-designing it with patients — asking where they would want the patch placed, what concerns they had, and what would help them feel confident monitoring it at home. We developed silicone simulation models to show patients exactly what normal skin and rejecting skin look like, so they know when to call us.

Clinical recruitment is now open at Saint Vincent's University Hospital. We are grateful to the Spark Innovation team, Research Ireland, and to Jonathan McCrea and the Future Proof Extra team for helping us share this work with a wider audience.

You can listen to the podcast here: https://www.goloudplayer.com/podcasts/futureproof-with-jonathan-mccrea-40.