Time-Tested Transplants

In hemophilia, a mutated gene prevents the production of a critical blood-clotting protein. What if the body could be induced – by a transplant of healthy tissue – to begin producing this protein?

 

In research recently published in the Proceedings of the National Academy of Sciences (PNAS), Prof. Yair Reisner and Ph.D. student Anna Aronovich of the Weizmann Institute’s Immunology Department, together with colleagues, showed how such a transplant might in the future be made feasible.

 

By taking spleen tissue from embryonic pigs, the scientists found that harmful T cells, which are responsible for severe immune responses against the recipient, are not present prior to day 42 of gestation. They also found that tissue of this age exhibits optimal growth potential and secretes factor VIII, the blood-clotting protein missing in hemophilic patients. Hemophilic mice with spleen tissue transplanted from pig embryos at 42 days of gestation experienced completely normal blood clotting within a month or two of implantation.

 

Although a number of problems would need to be surmounted before researchers could begin to think of applying the technique to humans, the Institute team has provided evidence that transplanted embryonic tissue, whether human or pig, could one day help the body overcome hemophilia and other such genetic diseases.