LARGE-SCALE ISOLATION, GROWTH, AND FUNCTION OF PORCINE NEONATAL ISLETCELLS

Based upon existing methods of isolating fetal porcine islet tissue, a simple, reliable procedure was developed for the preparation of porci ne neonatal islet cell aggregates with a reproducible and defined cell ular composition. After 9 d of in vitro culture, tissue from one neona tal pig pancreas yielded similar to 50,000 islet cell aggregates, cons isting of primarily epithelial cells (57%) and pancreatic endocrine ce lls (35%). During the culture period, the total beta cell mass decreas ed initially, but subsequently increased 1.5-fold between days 3 and 9 , Transplantation of grafts consisting of 3 x 10(5) beta cells (1,000 aggregates) under the kidney capsule of alloxan-diabetic nude mice cor rected hyperglycemia in 75% (10/13) of the animals, whereas, 100% (20/ 20) of recipients implanted with 6 x 10(5) beta cells (2,000 aggregate s) achieved euglycemia within 8 wk posttransplantation. Nei phrectomy of the graft bearing kidney at 14 wk posttransplantation resulted in h yperglycemia in all recipients, and examination of the grafts revealed the presence of numerous well-granulated insulin- and glucagon-contai ning cells. The cellular insulin content of these grafts was 20 to 30- fold higher than at the time of transplantation. These results indicat e that the neonatal porcine pancreas can be used as a source of large numbers of viable islet cells, which have the potential for growth bot h in vitro and in vivo, and exhibit the metabolic capacity to correct diabetes in nude mice.