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Vascular grafts from the bioreactor

Vascular grafts from the bioreactor

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Bypasses made from human cells could become an alternative to synthetic materials in the future

It is a vision that may open up entirely new opportunities in the treatment of circulatory disorders: biologically compatible bypasses made from the patient's own cells. Bypasses from blood cells and tissue cells cultured in a bioreactor will probably be a considerably better tolerated alternative to conventional bypasses, which are made of synthetic materials. At NIFE (Lower Saxony Centre for Biomedical Engineering, Implant Research and Development), an interdisciplinary team of researchers from Leibniz Universität Hannover is working on such vascular grafts, and was recently awarded the Association of German Engineers' (VDI) 2017 Engineering Award.

Circulatory disorders in arteries sometimes lead to a heart attack or a stroke in worst-case scenarios. In these cases, it is essential to insert bypasses. In the case of vascular grafts made of synthetic material such as Gore-Tex, patients must take medicine for the rest of their lives to reduce blood clotting, because otherwise they run the risk of blocking the bypass due to the material structure, and vascular occlusion would reoccur. The use of anticoagulants is not easy and may lead to complications. In addition, synthetic bypasses can become infected. Autologous venous material that can be taken from another part of the patient's body and used is often unavailable in sufficient quantity and quality. For this reason, there is great demand for artificial vascular grafts.

Research on bypasses made from animal tissue has been conducted for quite a long time ‒ however, in addition to ethical concerns, there have been problems with rejection and deposit processes so far. The scientists from Leibniz Universität Hannover, however, have taken another path. They have been attempting to colonise patient cells on a tubular scaffold consisting of synthetic material. After a cultivation process in the bioreactor, a bypass emerges on this scaffold, which can then be implanted. The scaffold is later dismantled so that the vascular graft only consists of material produced by the body.

Scientists from the Institute of Technical Chemistry and the Institute of Microelectronic Systems have been working together to develop the technology for the cultivation. "The conditions in the bioreactor must be based on those in the human body," explained Professor Dr. med. Cornelia Blume of the Institute of Technical Chemistry. Heartbeat and blood pressure are simulated so that a bypass is generated within two or three weeks. "Further gestation processes take place after the implantation into the body. Man is the best bioreactor," she added. The highly sensitive regulation and sensor technology and the ultrasound monitoring system ‒ during the process, the bioreactor must be sealed practically the entire time ‒ was developed by Professor Dr.-Ing. Holger Blume and his team at the Institute of Microelectronic Systems.

In this project, funded by the German Research Foundation (DFG), the researchers have been working closely together with Hannover Medical School as well as with other partners. Implementation of this project does not seem too far away: "We hope that in three years' time we will be able to test the bypasses in experiments with sheep," said Professor Cornelia Blume. This would be followed by a clinical phase with an approval procedure in humans.

Notes for Editors

For further information please contact Prof. Dr. med. Cornelia Blume, Institute of Technical Chemistry, telephone +49 177 8669328, E-Mail blume@iftc.uni-hannover.de.