The bioartificial pancreas: from myth to clinical reality

Transplantation of human pancreatic islets has demonstrated its feasibility and clinical efficacy. It restores glycemic control in brittle type 1 diabetic patients. However, it requires the establishment of an immunosuppressive treatment that is not without consequences for the patient. In addition, its application to a large number of patients remains limited by the number of pancreas and the number of islets available. Moreover, the low yields of isolated islets associated with the number of islets required per patient to achieve insulin independence also contribute to limiting this therapy to a very small number of patients. Other sources of insulin-secreting cells are now available: xenogenic cells or stem cells. However, their use in transplantation remains constrained by their risks because these cells are transplanted free into the body. To answer to this constraint, the concept of bioartificial pancreas has been developed to apply cellular therapy to a larger number of patients through access to other sources of insulin-secreting cells without any immunosuppressive regimen. The principle of the bioartificial pancreas is thus to encapsulate insulin-secreting cells in semi-permeable systems that are immunoprotective but allow the passage of oxygen, nutrients, glucose and insulin. It is therefore essential that a bioartificial pancreas fulfills the three prerequisite functions: protect the cells from the recipient's immune system, protect the recipient to these cells, maximize the function of these cells. Various approaches have thus been considered from microencapsulation to macroencapsulation. The development of the latter as well as its clinical validation is currently underway.