EFFECTS OF COLLAGENASE CONCENTRATION ON THE PURITY AND VIABILITY OF ISOLATED PORCINE PANCREATIC-ISLETS FOR USE IN XENOTRANSPLANTATION STUDIES

The use of lower concentrations of collagenase (0.8 mg/ml as compared to 1.25 and 1.5 mg/ml) resulted in isolation of porcine pancreatic isl ets retaining their original compact, wholesome appearance. In in vitr o experiments, 100% of islet batches isolated with the low collagenase concentration responded to glucose stimulation, while only 63.1% of i slet batches isolated with the high concentration of the enzyme did. T he response to high glucose challenge of islets isolated with the low enzyme concentration was considerably higher compared to high collagen ase concentration islets. In in vivo experiments, intraperitoneal tran splants of microencapsulated islets isolated using 0.8 mg/ml of collag enase reversed diabetes in diabetic BALB-c mice in a significantly lar ger proportion of recipients (87.5%) as compared to 33.3% of recipient s grafted with 1.5 mg/ml collagenase islets. The results of this study demonstrate that the use of a low collagenase concentration is conduc ive to isolation of islets of a superior morphology, purity, viability , and functioning ability.