Recently, a new study published in Nature - Communications showed that bioengineered blood vessels that replace the pulmonary artery can grow in the recipient in three lambs. If proven in humans, the new vascular graft will keep young patients from having to undergo repeated surgery. One of the biggest challenges in bioengineering synthetic blood vessels is that the designed blood vessels can change shape after transplantation and co-grow with their new receptors without being rejected by the immune system. Scientists have been working to develop ways to produce such blood vessels, but they need to be carefully prepared using the patient's own cells, long processes, and need to be cultured in the laboratory prior to transplantation. Robert Tranquillo of the University of Minnesota, USA, and colleagues developed blood vessels that fit into storage and are transplanted when needed, without the need to train individual bespoke vessels in the lab. The way they make such artificial blood vessels is to put sheep skin cells in a special tube and regularly push the nutrients needed for cell growth. Regular push can help cells store proteins around them, making the vessels produce the proper mechanical properties. Sheep cells are eventually flushed out leaving only "non-cellular" protein scaffolds that do not elicit an immune response. In fact, when these newly formed acellular vascular grafts replace part of the pulmonary arteries of three lambs, the lamb's own cells quickly fill the transplanted blood vessels, deform the blood vessels and co-grow with the recipient until adulthood. The researchers did not observe adverse reactions, such as coagulation, vascular narrowing or calcification. Although the results of this proof-of-concept study are encouraging, further research, including larger-scale animal studies, is needed before it can be determined that the method is effective and safe for human testing. HUZHOU JIHAO NONWOVENS FABRIC CO.,LTD , https://www.jihaononwovens.com