Living Cell Technologies Limited has published a paper in the November issue of the Journal of Clinical Microbiology which demonstrates the long-term safety of transplanted insulin-producing pig islets in people with type 1 diabetes.
LCT monitored 18 human patients who had received pig islets for up to nine years post-transplantation. The data showed that the islet transplants were well tolerated by all patients and that none of the patients were infected with viruses from pigs.
"This new evidence confirming the safety of pig islet transplantation goes a long way toward alleviating the concern that dormant viruses of pig origin may become active in patients who receive transplants," said Professor Bob Elliott, LCT's Medical Director.
Pig islet transplantation is of particular interest to medical practitioners and patients alike, since implanted islets can replace the insulin-producing function of the pancreas which is lost in individuals with type I diabetes. The extremely limited availability of suitable human islets for transplantation makes the therapeutic use of pig islets an important alternative, particularly because pig insulin is almost identical to human insulin and has been used clinically since the early part of last century.
Since the late 1990s there have been questions about the risk that recipients of therapeutic implants containing pig cells may become infected with PERV (porcine endogenous retrovirus).
All cells, including human cells, have species-specific endogenous retroviruses. While PERV has been found in the genetic material of all pigs, there is no evidence to date that pig viruses have infected any of the 200 or so humans who have been exposed to cells derived from pigs.
Using sensitive methods for the detection of pig viruses (including PERV), LCT, which is considered to have one of the world's leading groups in the field of pig virology, found no evidence of infection by pig viruses in plasma or white blood cells taken from the patients.