Secondary purification of islets by the use of immunomagnetic separation techniques.

Type I diabetes 1.1% of the population in the UK affects. Whilst insulin injections can control diabetes it has been shown that the frequency of secondary complications are only reduced by strict glycemic control. Pancreas transplants have been carried out to reverse diabetes. However, due to the severity, the morbidity and mortality of the procedure, only patients who have already received a kidney transplant and therefore have secondary complications have undergone such a procedure. Pancreatic islet transplantation is a less invasive procedure. Since the 1980's, reports of clinical islet transplantation using purified and unpurified islets have been made. Studies in the animal model, recent reports from clinical studies, and work carried out in this thesis, have emphasised the need to purify islets prior to transplantation. Islets are purified by the use of density gradients. However, due to the overlapping densities of the islet and exocrine tissue, complete separation cannot be achieved. Therefore a more specific method is needed to increase the yield of islets obtained from a cadaver donor pancreas. This thesis describes the development of a system using immunomagnetic techniques for the purification of islets. Using a quadripolar magnetic field into which the digest is released from a vibrating pipette with the addition of BSA prior to release, islets can be successfully purified with a loss of only 25%. The system can be used as a secondary purification following density dependent purification to increase the yield of islets from a single pancreas, making one donor to one recipient transplants a realistic option.