Sertoli cell-induced defects on functional and structural characteristics of isolated neonatal porcine islets

A lack of a sufficient number of human donor pancreases has stimulated interest in isolation and cryopreservation techniques for islets from the porcine pancreas. But because of a poorly developed outer membrane porcine islets are particularly susceptible to damage during cryopreservation. The aims of this study were two-fold: 1) to develop a method for isolation and storage of islets from neonatal porcine pancreas and, 2) to examine effects of Sertoli cells on islet yield and function in Sertoli cell-islet cell cocultures. A total of 170 neonatal porcine pancreases were processed by means of a short period of digestion with collagenase and culture of the tissues at 32 degrees C for periods up to 7 days following isolation. Results were: The mean +/- SEM, number of viable islets, and percentage loss of cells following 7 days of culture were 29,442 +/- 1,119 and 22.2 +/- 1.2, respectively, Cryopreservation had a marked impact on recovery of viable islets: In absence of Sertoli cells an average of only 64% of islets remained viable; by contrast, when cryopreserved islets were cocultured with Sertoli cells, a mean of 82% was recovered. Glucose at 16.7 mmol/L had the capacity to elicit insulin release from 3-day-old cultured islets. The concentration in absence of Sertoli cells was 57.3 +/- 3.8 uU/mL/10 islets; in the presence of Sertoli cells the level increased to a mean +/- SEM of 112.8 +/- 17.7, uU/mL/10 islets. Similar results were obtained following cryopreservation: glucose at 16.7 mmol/L stimulated a mean +/- SEM of 27.9 +/- 6.6, uU/mL/10 islets, of insulin in absence of, and 44.9 +/- 9.9, uU/mL/10 islets, in presence of, Sertoli cells. Our results show that isolation and cryopreservation of neonatal porcine islets can be successfully accomplished. In addition, coculture with Sertoli cells significantly improves both the yield and functional capacity of islets following cryopreservation.