A method for the large scale production of microencapsulated islets: in vitro and in vivo results

We have developed a semi-automated method for the large-scale production of high mammal pancreatic islet containing microcapsules, comprised of alginic acid and aminoacidic polycations. We have been able to scale-up procedures originally developed for rodent islets and render them suitable for bulk, high mammal islet microencapsulation. Physical/chemical properties of these microcapsules, fabricated on a large-scale basis, were shown not to adversely affect the long-term in vitro retention of islet morphologic integrity, viability and function. Transplantation of human islets, encapsulated by this method, into non-immunosuppressed, spontaneously diabetic rodents or dogs resulted in a substantial reversal of hyperglycaemia, which was either partial or complete, demonstrating suitability of this procedure for in vivo clinical application. The procedure may offer the opportunity to immunoprotect large-size mammalian islet grafts with no requirement for immunosuppression of the recipients and, eventually, to employ non-human tissue as a source of donor islets.