Is tissue engineering poised to transform heart bypass surgery?

Tissue engineering is one of the hottest fields in 21st century medicine, and last year I discussed how one leading scientist in this field, Professor Laura Niklason of Yale University, has made important strides in the development of artificial arteries. Now scientists led by Laura Niklason have announced another important milestone in the development of artificial blood vessels; blood vessels that she hopes will be suitible for many patients undergoing operations such as heart bypass surgery for whom no other suitible blood vessels are available for transplant.

Artificial blood vessel produced using human cells by scientists at Humacyte. Image courtesy of Science/AAAS

In a publication in Science Translational Medicine the scientists at Humacyte describe how atificial blood vessels were constructed by growing human  or canine smooth muscle cells on a tubular polyglycolic acid scaffold, and implanted respectively in baboons to to join an artery, and in dogs as a coronary artery bypass graft .  The success of these transplants, which demonstrated excellent safety and blood flow in dogs and baboons for up to one year after implantation, has generated quite a lot of media excitement. The MIT technology review has a good account of the study and the background to it, citing Professor David Putman of Cornell University who said concerning the study that:

The researchers’ use of baboons also provides important additional support before they move into human trials. The reason is that the dynamics of blood flow in baboons are a good model for what happens in humans.”

While most of the reports suggest that clinical trials of these articficial blood vessels will start in the very near future, a report on the NHS website highlights the observation by Laura Niklason and colleagues that the number of animals used in these studies was quite small, and that further animal studies of longer duration will be necessary before clinical trials in humans can begin. Nevertheless this is a significant medical advance, and I hope that the further animal studies, which are probably under way as I write, confirm the excellent results seen in this weeks report and allow clinical trials to commence.

Paul Browne