A research group at the Texas Biomedical Research Institute in San Antonio, Texas has reprogrammed embryonic stem cells derived from baboon embryos to completely restore a severely damaged artery. Such results lay the ground work for what might be a new way to completely heal large blood vessels that have been damaged by congenital diseases, the ravages of disease, or simply old age.
John L. VandeBerg, chief scientific officer at the Texas Biomedical Research Institute, said: “We first cultured the stem cells in Petri dishes (culture dishes) under special conditions to make them differentiate into cells that are the precursors of blood vessels, and we saw that we could get them to form tubular and branching structures, similar to blood vessels.”
Since VandeBerg and his colleagues were able to differentiate baboon embryonic stem cells into blood vessel precursors, they wanted to try a much more difficult experiment and try to use these blood vessels precursor cells to repair a damaged blood vessel in a simulated environment.
By removing the cells that line the inside of a baboon artery, VandeBerg and co-workers replaced the lining with the blood vessel precursors derived from baboon embryonic stem cells. Then they connected this artery segment to a plastic tubing inside a device known as a “bioreactor.” Bioreactors are designed to grow cells and tissues under conditions that closely mimic those inside the human body. In this case, the bioreactor also pumped fluid through it as though it were inside a real, living baboon.
The artery was bathed in culture medium, and by three days, the complex inner layer of the artery showed signs of regenerating, and by 14 days, it was perfectly restored to its complex, natural state. In two weeks, the artery had gone from stripped to a fully functioning artery.
VandeBerg said of these experiments: “Just think of what this kind of treatment would mean to a patient who had just suffered a heart attack as a consequence of a damaged coronary artery. And this is the real potential of stem cells regenerative medicine – that is, a treatment with stem cells that regenerates a damaged or destroyed tissue or organ.”
A control experiment also showed that the arteries could not regenerate without the added cell stems, they used an artery that can been internally stripped and hooked it up to the bioreactor without seeding it with stem cells. Under these conditions, no healing occurred.
When the arteries were stained for those proteins normally found in a properly functioning artery, the healed artery showed all the same staining characteristics as arteries that had not been internally stripped. Of this result, VandeBerg noted: “This is evidence that we can harness stem cells to treat the gravest of arterial injuries.”
Researchers such as Vandeberg hope to take a skin cell or a white blood cell, or a cell from just about anywhere else in the body and induce it to differentiate into induced pluripotent stem cells that can be used to differentiate into blood vessel precursors that can be used to repair damaged blood vessels.