THE LACK OF INTERACTION BETWEEN TRANSPLANTED HUMAN FETAL PANCREAS ANDLIVER

Trophism between transplanted hepatocytes and pancreatic endocrine tis sue has been demonstrated with both adult and late gestational fetal t issue. Since this effect has not been looked for with fetal tissue obt ained early in pregnancy, we conducted a series of experiments transpl anting human liver and pancreas, which was obtained early in the secon d trimester (15-20 weeks gestation), beneath the renal capsule of athy mic mice. Fetal pancreatic explants increased in size after transplant ation into nondiabetic mice, but their insulin content 11 weeks later was not different from that of grafts that included liver explants. Re versal of diabetes was achieved in 2 of 5 diabetic mice transplanted w ith pancreas alone, but none of the mice that received pancreas and li ver became normoglycemic. Histological examination of grafted liver ex plants, which consist of hepatocytes and hematopoietic cells, showed t hat hepatocytes survived for only two weeks regardless of the presence of pancreatic explants. Bile ducts differentiated by this time in bot h groups and were still present at 7 weeks. In conclusion, there was n o trophic effect observed between transplanted fetal human liver and p ancreatic endocrine tissue obtained early in pregnancy; bile duct diff erentiation is a feature of fetal human liver xenografted into the ath ymic mouse.