Genetically Modified Swine Skin Grafts may Provide New Treatment for Severe Burn Victims

Skin grafts from genetically modified pigs could help to treat severely burned patients. Pigs that are lacking the Gal sugar molecular were shown to provide effective covering in burn-like injuries on the backs of baboons as skin taken from the animals.

"This exciting work suggests that these GalT-knockout porcine skin grafts would be a useful addition to the burn-management armamentarium," said Curtis Cetrulo, MD, of the MGH Transplantation Biology Research Center (TBRC) and the Division of Plastic and Reconstructive Surgery, via a press release. "We are actively exploring options for establishing clinical-grade production of these grafts and hope to begin a clinical trial in due course."

As a key component of treatment for major burns involves more removing and covering of the damaged area with a graft of the patient's own tissue, samples from deceased donors can work as a temporary covering. However, these are often in short supply and rather expensive. They also must be carefully tested for pathogen's so that the tissue is not rejected by the patient's immune system. The study adds that once a deceased-donor graft has been rejected, a patient's immune system will subsequently decrease future donor grafts immediately following.

For the study, researchers developed a strain of inbred miniature swine with organs that are close to the size of adult humans. They used the strain to create miniature swine in both copies of the gene encoding GalT (galactosyltransferase). Signs of rejection for the grafts began around day 10, with complete rejection by day 12.

However, the study notes that, "if a pit-to baboon was followed by a graft using baboon skin, the second graft adhered to the wound and remained in place for around 12 days before rejection. The researchers also showed that acceptance of a second graft was similar no matter whether a pig xenograft or a baboon skin graft was used first."

"These results raise the possibility not only of providing an alternative to deceased-donor skin for many patients but also that, in patients whose burns are particularly extensive and require prolonged coverage, sequential use of GalT-knockout and deceased-donor skin could provide extended, high-quality wound coverage," added co-author David Leonard, MBChB, of the TBRC and Division of Plastic and Reconstructive Surgery. "A high-quality alternative to deceased-donor skin that could be produced from a specially maintained, pathogen-free herd of GalT-knockout miniature swine would be an important resource for burn management in both civilian and military settings."

More information regarding the findings can be seen via the journal Transplantation.