Electrostatic Droplet Generation Research Articles

Free and Microencapsulated Adrenal Cortical Cells Produce Similar Cortisol Responses When Stimulated by Acth: An in vitro study

Transplantation of endocrine cells, especially when protected from immune destruction, is an attractive alternative to whole organ transplantation. The current treatment for adrenal insufficiency whether congenital or acquired is hormone replacement, which is not considered fully physiological. In this study, we isolated porcine adrenal cortical cells by collagenase digestion. The cells were microencapsulated in alginate-polylysine-alginate membranes using electrostatic droplet generator. In vitro, ACTH stimulation of both free and microencapsulated adrenal cortical cells produced comparable cortisol response. It can be concluded that the microencapsulation process is not injurious to the adrenal cortical cells and that it does not hamper their secretory function.

Porcine pancreatic islets: isolation, microencapsulation, and xenotransplantation.

To provide a plentiful source of pancreatic islets for future clinical transplants into diabetic patients, we have developed a simple and reliable method to isolate porcine islets of a high degree of purity. Porcine pancreata were perfused and digested with collagenase, and the islets were then purified on dextran density gradients. In order to avoid any damage to the islets, no mechanical devices nor any strenuous treatment was employed. As many as 5 x 10(5) islets were isolated from a single porcine pancreas. Islets were encapsulated in alginate-polylysine-alginate membranes with the aid of an electrostatic droplet generator. In vitro studies demonstrated that the isolated islets secreted insulin in response to glucose and 3-isobutyl-L-methylxanthine (IBMX) challenge for at least 4 weeks. Perifusion studies showed that the kinetics of insulin release from the encapsulated islets was similar to that exhibited by free islets. In in vivo studies, 18 diabetic BALB-c mice were transplanted with 1,500-2,500 encapsulated islets each. In 13 recipients, the diabetic condition was reversed for at least 85 days. When capsules were removed from 2 transplant recipients, their diabetic condition quickly recurred.