Heart valves that grow with the patient

When German President Horst Köhler awards the German Future Prize for 2008 on 3 December in Berlin, researchers and research projects funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) will once again be the focus of attention. Professor Axel Haverich, a heart surgeon and Leibniz prizewinner from Hannover Medical School (MHH), and his two colleagues Dr. Serghei Cebotari and Dr. Michael Harder are one of four teams who have made the final round of the President's award for engineering and innovation, worth 250,000 euros. This is the result of the preliminary selection that was announced on Tuesday by the Head of the Office of the Federal President, Undersecretary of State Dr. Gert Haller, in Berlin. The three scientists were nominated for the development and successful transplantation of tissue engineered biological cardiac valves for children , which grow with the patients – an innovation in both medicine and medical technology which has been supported by the DFG with funds from the Gottfried Wilhelm Leibniz Prize.

The "decellularised and re-colonised pulmonary valves" developed by Haverich and his team provide child patients with significantly improved chances of survival and a better quality of life. In Europe around 1,200 heart valve transplants a year are performed on children. The mechanical heart valves normally used in these operations have the disadvantage that they require lifelong blood thinning treatment and are susceptible to infections. The biological heart valves from pigs or cows used as an alternative are again only of limited durability. Children with heart valve defects therefore normally have to undergo multiple operations – with all the physical and psychological pressures and risks this entails.

Haverich and his colleagues, on the other hand, use heart valves that are "grown" from the young patient's natural body cells. To do this, a valve from a human or animal donor is removed of all cells using tissue engineering, so that only its outer framework remains. This valve matrix is then colonised with cells that have been obtained from the blood of the recipient and propagated. Within a few weeks, a quasi-natural heart valve then emerges in this bioreactor, that exhibits no rejection response or other faults, but instead grows with the patient after the implantation.

The foundation for this innovation in medicine and medical technology was laid in 1995. In that year the then 42-year old Haverich was honoured by the DFG with Germany's most prestigious research prize, the Leibniz Prize, for his groundbreaking scientific work in the area of transplant medicine. One year later Haverich used the prize money of three million German marks at that time to found the Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO) at Hannover Medical School. The first major project of the new establishment was the development of "grown" heart valves. After six years of development work and experiments on small and large animals, in May 2002 Haverich was able to implant the first decellularised and re-colonised heart valves into two children of nine and ten years of age. Since then 16 children have been successfully operated on. The first two patients have now been living with their new cardiac valves for over six years – free of illness and comparable with healthy children in terms of their physical development.

Haverich and his colleagues have documented the scientific bases of their new treatment in great detail in numerous publications. A series of patents and the establishment of two companies also testify to the strong market potential of their innovation. This should grow considerably further if such heart valves can also be implanted in adults, a declared aim for Haverich. His work has since received further impetus from the Excellence Initiative by the German federal and state governments, which is funding the excellence cluster "From Regenerative Biology to Reconstructive Therapy" (Rebirth) at the MHH, in which Haverich is developing new methods of growing tissue in his role as coordinator. All this has convinced the jury made up of renowned experts from science and business in the preliminary selection for the Federal President's Future Prize.

The German Future Prize has been awarded annually since 1997 and is considered the most important innovation award in Germany. It is given by the Federal President to honour scientists and inventors who, based on excellent research, initiate the process of bringing credible projects and products to the market. This, in the DFG's view, is what Axel Haverich does outstandingly well: "Professor Haverich is a surgeon and scientist recognised the world over with outstanding publications and patents, who at his clinic promotes an extraordinarily technology- and innovation-friendly climate," emphasised DFG President Professor Matthias Kleiner.

Haverich stands for the combination of research and clinical practice at the highest level, continued Kleiner, and is moreover committed in many different ways to scientific self-governance, most of all in the DFG Senate, of which he was a member from 2001 to 2007, and in the Senate Commission for Clinical Research.

But the nomination for the Future Prize is not only a distinction for Haverich himself, but also an affirmation of the Leibniz Prize, emphasised the DFG President. The prize, which has been awarded since 1986, brings its winners not only worldwide renown and large prize money, but also the freedom to use this money for independent research projects of their choice with a minimum of red tape. Six Leibniz recipients later went on to receive the Nobel Prize. "These heart valves that grow with the patient are impressive evidence for the forward-looking way in which this freedom can be used," Kleiner said. With his pioneering development Haverich certainly has a good chance of success in the final selection at the beginning of December: "The Future Prize would be a well-deserved accolade for his outstanding work."

Source : Deutsche Forschungsgemeinschaft