Another problem in treating CNS disorders with brain grafts is finding effective therapeutics that can regulate secondary complications due to the insult to the host tissue and the presence of foreign cells that can also cross the BBB.
The porcine xenograft concept is not new; pig heart valves have been used for years, Pig-to-human islet cell transplants have already undergone clinical trials, and a few Parkinson's patients have received brain grafts of fetal pig neural tissue.