A team of researchers at the University of Minnesota Medical School recently grew human-derived blood vessels in a pig — a novel approach that has the potential for providing human vessels for transplant purposes.

Because these vessels were made with patient-derived skin cells, they are less likely to be rejected by the recipient and might help patients avoid the need for life-long, anti-rejection drugs, according to the researchers, whose study was published in Nature Biotechnology.

Because of similarities between human and pig physiology, scientists have historically studied pigs to discover treatments for health issues, including diabetes. Before researchers engineered human insulin, doctors treated patients with pig insulin.

The Minnesota researchers believe the blood vessels they created will avoid rejection because of the method by which they are made. They injects human-induced pluripotent stem cells, taken from mature cells scraped from a patient’s skin and reprogrammed to a stem cell-state, into a pig embryo. The embryo  is then placed into a surrogate pig. Viable piglets with blood vessels that will be an exact match to the patient will ensure a successful transplant and the ability to live without the need for immunosuppression drugs, the researchers said in a press release.

“There’s so many chronic and terminal diseases, and many people are not able to participate in organ transplantation,” said co-lead researcher Dr. Daniel Garry, who is also a heart failure and transplant cardiologist. “About 98% of people are not going to be eligible for a heart transplant, so there’s been a huge effort in trying to come up with strategies to increase the donor pool. Our approach looked at a pig.”

The lining of the blood vessels is what typically causes rejection of donated organs, Garry added. “This could allow us to make organs with human blood vessels that would be less apt to be rejected and could be used in patients in need of a transplant.”

The first phase of their study, approved by the university’s stem cell research oversight committee, brought the first embryo to a 27-day term. The team is now seeking the committee’s approval to advance the research further into the later gestational period.

“There’s hundreds of thousands of patients that have peripheral artery disease, either because of smoking or diabetes or any number of causes, and they have limb amputations,” said co-lead researcher and University of Minnesota School of Medicine professor Mary Garry. “These blood vessels would be engineered and could be utilized in these patients to prevent those kinds of life-long handicaps, if you will…

“While it is a first phase, there’s pretty solid proof of concept,” she added. “We believe that we’ve proven that there’s no off-target effects of these cells, so we’re ready to move forward to later gestational stages.”