FUNCTION AND FATE OF AGAROSE MICROCAPSULES CONTAINING ALLOGENEIC ISLETS IN RAT RECIPIENTS

Implantation of microencapsulated islets has been considered one of th e promising approaches to treat insulin-dependent diabetic patients. I n this study, microcapsules made of agarose hydrogen were applied to a llogeneic islet transplantation between F344/Jcl and ACI/N Jc1 ms. Imp lantation of 1000 microencapsulated islets normalized the fasting bloo d sugar level for 118 +/- 38 days. Of the microcapsules transplanted 5 5 +/- 3.1% were occluded into the greater omentum, 26 +/- 2.0% were pr esent at the space between intestinal tubes and 10 +/- 1.4% in the pel vic cavity. Laparotomy revealed a good tone of the intestine without s tenosis and dilatation. However, microscopic examination revealed that some of the microcapsules induced an inflammatory reaction and migrat ed into the liver tissue. A large volume of the microcapsules remainin g in the abdominal cavity might induce adverse effects on the recipien t in clinical application. These findings suggest that new materials s hould be developed for microencapsulation of islets in order to mainta in their immunoisolative ability during islet fractioning, be spontane ously resolved or be removed without suggest procedure after the micro capsules have finished their duty. (C) 1998 John Wiley & Sons, Ltd.