The isolation of porcine islets of Langerhans.

Chapter One reviews diabetes mellitus and its treatment. Chapter Two reviews the history and development of islet isolation techniques in both animals and humans. Chapter Three presents the physiological profile of the pig, its relevance as a human model and results of investigations into porcine pancreatic morphology and histology. Studies into porcine islet isolation are reviewed. Xenotransplantation is reviewed, with a view to the use of pig islets in the treatment of diabetes. Chapter Four describes the isolation of porcine islets using a manual digestion technique. Results of islet quantification in the digest and the results of islet separation on a bovine serum albumin density gradient are given. Chapter Five describes the effect of bovine serum albumin osmolality on the separation of porcine islets. Chapter Six is an experimental comparison of the manual digestion method already described with an automated method. A direct comparison between the two is made using simultaneous digestion by each method. Chapter Seven describes attempts at the optimization of the automated digestion technique in order to improve the purity of isolate islets., i.e. to improve their behaviour on a density gradient. Modifications to the automated method are described. Each modification and the rationale behind it is described, along with the effects on pancreatic digestion, islet morphology and islet / exocrine separation. Chapter Eight describes the large-scale isolation of porcine islets after optimized automated digestion as above. The large-scale isolation is performed on a commercial cell separator in which a hyperosmolar bovine serum albumin density gradient, determined by the results in chapter five, is constructed. The effect of the transplantation of such isolated islets into diabetic severe combined immundeficient (SCID) mice is studied and results given. Conclusions are discussed and suggestions made for future research.