BackgroundAllogeneic islet transplantation has become a viable option for the treatment of unstable type 1 diabetes. However, the donor shortage and the necessity of the immunosuppressive drugs are two major issues. To solve these issues, we performed islet xenotransplantation using encapsulated neonatal porcine islets without immunosuppressive drugs.MethodsTwo different doses (approximately 5000 IEQ/kg and 10,000 IEQ/kg) of encapsulated neonatal porcine islets were transplanted twice (total approximately 10,000 IEQ/kg and 20,000 IEQ/kg) into four type 1 diabetic patients in each group (total 8 patients).FindingsIn the higher dose group, all four patients improved HbA1c. This was maintained at a level of < 7% for > 600 days with significant reduction of the frequency of unaware hypoglycemic events.InterpretationThe clinical benefit of islet xenotransplantation with microencapsulation has been shown.

Background: Recently, significant progress in both safety and efficacy has been achieved in the field of xenotransplantation, as exemplified by results from the first clinical trials of porcine islet transplantation. It would be of interest to learn whether the attitude of the clinical staff involved in such trials changes as the trials are carried out in their own hospital.

Allogeneic islet transplantation has become a viable treatment for unstable type 1 diabetic patients. 1 On the other hand, donor shortage is a serious issue and xenotransplantation, especially using porcine organ, is a promising approach to remedy this situation. 2,3 We have conducted clinical trials of alginate microencapsulated neonatal porcine islets for unstable type 1 diabetic patients in NZ 4,5 and Argentina. 6,7 The alginate microcapsules in which porcine islets were administered are "minimal volume" microcapsules 600 to 900 µm in diameter and have small pores which allow glucose and nutrients to diffuse in and insulin to diffuse out, but the larger

Progress in porcine islet xenotransplantation has been accompanied by studies on acceptance of this new procedure by patients, health professionals or the general public. Such studies have not been done in the Latin-American population. We conducted a questionnaire in 108 diabetes patients (insulin-dependent, n = 53; insulin-independent, n = 55) in a public hospital in Argentina. The questions addressed the general perception of the xenotransplant procedure and specific items related to the outcome (achieving insulin independence, improvement in metabolic control, delay in emergence of diabetic complications, need for repeat procedures, potential of transfer of infectious viruses, association with psychological problems, and anticipated success in relation to achieving a cure). Eighty-six (79%) of the patients accepted islet xenotransplantation; this incidence was not different for insulin-dependent or insulin-independent patients, patients with or without complications, or patients with good or poor metabolic control. Also, over 75% of patients accepted the procedure if this is only associated with a reduction in insulin requirement, if the procedure just delays but not prevents the onset of complications, or if the procedure needs to be performed every 6 months. Fifty-seven percent of patients indicated acceptance even if the potential transmission of a virus infection cannot be completely ruled out: this outcome was not affected by the outbreak of the H1N1 flu epidemic during the conduct of this study. Forty percent of patients indicated that living with porcine cells in their body could give psychological problems. We conclude that this population of Latin-American diabetic patients shows a high acceptance rate of a porcine islet xenotransplantation product.