The bio-engineered blood vessels are taken from a postnatal donor’s skin cells and then developed within a laboratory. The process creates vessel-like tubes, and these can be transferred into a patient and used successfully as replacement blood vessels.
The blood vessels are developed by combining sheep skin cells with fibrin (gelatinous material.) the two are then mixed in a bioreactor, which creates the favourable conditions for cell growth. Within the bioreactor the cells are strengthened and the resultant material is the basis of the bioartificial vessels.
At the end of the process, the structure is treated with detergents in order to remove any remaining sheep cells. The end structure contains no cellular components. In tests the artificial blood vessels are stronger than natural arteries.
The blood vessels have been tested in animals, working on lambs to undertake surgical procedures whereby pulmonary arteries were replaced. It was found that once the bioartifical vessel was implanted, the cells of the lamb grew around it and the artificial vessel became integrated as if it was a natural structure. This is seen as a success in terms of regenerative medicine.
It was later observed that as the lamb became a sheep, and continued to grow, the bioartifical vessel also grew, increasing by over 50 percent in diameter. This allowed blood to continue to be pumped through to support the larger animal. No adverse effects, like blood clotting, were observed.
The lead researcher, Dr. Robert Tranquillo has explained to QMed that the development is the first of its kind. The main application will be with children who suffer from heart defects.
With this, Dr. Tranquillo said: “This might be the first time we have an ‘off-the-shelf’ material that doctors can implant in a patient. In the future, this could potentially mean one surgery, instead of five or more surgeries that some children with heart defects have before adulthood.”
It is hoped to move the design to human trials and to undertake vascular grafts in children who have congenital heart defects. The research has been published in Nature Communications. The research paper is titled “Tissue engineering of acellular vascular grafts capable of somatic growth in young lambs.”
