New tissue-engineered blood vessel replacements closer to human trials

Researchers at the University of Minnesota have created a new lab-grown blood vessel replacement that is composed completely of biological materials, but doesn't contain any living cells at implantation, the university announced
The vessel, that could be used as an “off the shelf” graft for kidney dialysis patients, performed well in a recent study with nonhuman primates, according to the announcement.

It is the first-of-its-kind nonsynthetic, decellularized graft that becomes repopulated with cells by the recipient's own cells when implanted, according to the researchers. The discovery could help tens of thousands of kidney dialysis patients each year. The grafts could also be adapted in the future for use as coronary and peripheral bybass blood vessels and tubular heart valves.

The research was published in Science Translational Medicine, an interdisciplinary medical journal by the American Association for the Advancement of Science (AAAS).
Currently, artificial grafts are made of synthetic materials are prone to clotting, infection and other complications. Grafts grown in the lab from cells and biological materials could cause fewer adverse reactions, but living tissues aren't stable for long-term storage and could induce an immune response unless the patient's own cells were used, both being barriers to commercialization and clinical use.
In this pre-clinical study, University of Minnesota researchers generated vessel-like tubes in the lab from post-natal human skin cells that were embedded in a gel-like material made of cow fibrin, a protein involved in blood clotting, according to the article.

Researchers put the cell-populated gel in a bioreactor and grew the tube for seven weeks and then washed away the cells over the final week. What remained was the collagen and other proteins secreted by the cells, making an all-natural, but non-living tube for implantation.
“We harnessed the body's normal wound-healing system in this process by starting with skin cells in a fibrin gel, which is Nature's starting point for healing,” said University of Minnesota Department of Biomedical Engineering Professor Robert Tranquillo who led the study. “Washing away the cells in the final step reduces the chance of rejection. This also means the vessels can be stored and implanted when they are needed because they are no longer a living material. In the future, thousands of the lab-grown vessels could be made from a small skin biopsy from one donor and then stored on the shelf for when they are needed by patients.”

Tranquillo is a BMES member

Read the full article HERE.
View the journal paper HERE