Experience with 100 combined pancreatic renal transplantations in a single center

Functional and morphological study of cultured pancreatic islets treated with cyclosporine

Cyclosporine A (CsA), a potent immunosuppressive drug, has been found to induce glucose intolerance through its toxic effect on the endocrine pancreas. It is not exactly known whether CsA has a direct effect on the endocrine pancreas or induces its effect indirectly. The present study was therefore undertaken to examine the function and morphology of isolated pancreatic islets when they are directly exposed in vitro to CsA. Pancreatic islets were isolated from adult male Lewis rats using collagenase ductal perfusion technique. The islets were separated with the discontinuous Ficoll gradient technique and further purified by hand picking of the non-islet tissue. The islets were cultured in RPMI-1640, pH 7.4 and maintained at 37 degrees C in a humid atmosphere of 5% (v/v) carbon dioxide in air. Cyclosporine was added to the culture medium to give a final concentration of 1 microg/ml (therapeutic dose), 5 microg/ml (toxic dose), or vehicle (control). Islets were harvested at 1, 4 and 10 days of culture and processed for functional or histological study. The functional study of the islets cultured with 1 microg/ml CsA showed insulin and C-peptide contents similar to those of the control islets. The islets cultured with 5 microg/ml CsA showed a marked decrease in insulin and C-peptide contents. Glucose-dependent insulin release was variable. C-peptide release was lower than that of the control following both the therapeutic and toxic doses of CsA. Phase contrast microscopy showed that the islets cultured with 1 microg/ml CsA were mostly normal looking with a well-defined regular periphery; a few islets had ill-defined or irregular peripheries. The islets cultured with 5 microg/ml CsA had ill-defined irregular peripheries at 1 day, and were dense and forming clumps at 4 and 10 days following culture. There was a decrease in the islet number following the therapeutic dose; the decrease was more following the toxic dose of CsA. The islet diameters increased after the therapeutic dose, but slightly decreased following the toxic dose of CsA. Islets showed a weakly positive immunoperoxidase reaction for insulin that was weaker following the toxic dose of CsA. It is concluded that CsA has a direct effect on B-cells that was proved by the functional and morphological changes seen in the pancreatic islets cultured in vitro.

Pancreas and islet cell transplantation

Currently, for the patient with type 1 diabetes, a definitive treatment without resorting to the use of exogenous insulin can be achieved only with pancreas or islet cell transplantation. These means of restoring beta-cell mass can completely maintain essentially normal long-term glucose homeostasis, although the need for powerful immunosuppressive regimens limits their application to only a subgroup of adult patients. Apart from the shortage of donors that has limited all kinds of transplantation, however, the widespread use of beta-cell replacement has been precluded until recently by the drawbacks associated with both organ and islet cell transplantation. Although the study of recurrence of diabetes has generated attention, the fundamental obstacle to pancreas and islet transplantation has been, and remains, the alloimmune response. With a better elucidation of the mechanisms of alloengraftment achieved during the last 3 years, the stage has been set for further advances.

Lessons learned from more than 1,000 pancreas transplants at a single institution

OBJECTIVE

To determine outcome in diabetic pancreas transplant recipients according to risk factors and the surgical techniques and immunosuppressive protocols that evolved during a 33-year period at a single institution.

SUMMARY BACKGROUND DATA

Insulin-dependent diabetes mellitus is associated with a high incidence of management problems and secondary complications. Clinical pancreas transplantation began at the University of Minnesota in 1966, initially with a high failure rate, but outcome improved in parallel with other organ transplants. The authors retrospectively analyzed the factors associated with the increased success rate of pancreas transplants.

METHODS

From December 16, 1966, to March 31, 2000, the authors performed 1,194 pancreas transplants (111 from living donors; 191 retransplants): 498 simultaneous pancreas-kidney (SPK) and 1 simultaneous pancreas-liver transplant; 404 pancreas after kidney (PAK) transplants; and 291 pancreas transplants alone (PTA). The analyses were divided into five eras: era 0, 1966 to 1973 (n = 14), historical; era 1, 1978 to 1986 (n = 148), transition to cyclosporine for immunosuppression, multiple duct management techniques, and only solitary (PAK and PTA) transplants; era 2, 1986 to 1994 (n = 461), all categories (SPK, PAK, and PTA), predominantly bladder drainage for graft duct management, and primarily triple therapy (cyclosporine, azathioprine, and prednisone) for maintenance immunosuppression; era 3, 1994 to 1998 (n = 286), tacrolimus and mycophenolate mofetil used; and era 4, 1998 to 2000 (n = 275), use of daclizumab for induction immunosuppression, primarily enteric drainage for SPK transplants, pretransplant immunosuppression in candidates awaiting PTA.

RESULTS

Patient and primary cadaver pancreas graft functional (insulin-independence) survival rates at 1 year by category and era were as follows: SPK, era 2 (n = 214) versus eras 3 and 4 combined (n = 212), 85% and 64% versus 92% and 79%, respectively; PAK, era 1 (n = 36) versus 2 (n = 61) versus 3 (n = 84) versus 4 (n = 92), 86% and 17%, 98% and 59%, 98% and 76%, and 98% and 81%, respectively; in PTA, era 1 (n = 36) versus 2 (n = 72) versus 3 (n = 30) versus 4 (n = 40), 77% and 31%, 99% and 50%, 90% and 67%, and 100% and 88%, respectively. In eras 3 and 4 combined for primary cadaver SPK transplants, pancreas graft survival rates were significantly higher with bladder drainage (n = 136) than enteric drainage (n = 70), 82% versus 74% at 1 year (P =.03). Increasing recipient age had an adverse effect on outcome only in SPK recipients. Vascular disease was common (in eras 3 and 4, 27% of SPK recipients had a pretransplant myocardial infarction and 40% had a coronary artery bypass); those with no vascular disease had significantly higher patient and graft survival rates in the SPK and PAK categories. Living donor segmental pancreas transplants were associated with higher technically successful graft survival rates in each era, predominately solitary (PAK and PTA) in eras 1 and 2 and SPK in eras 3 and 4. Diabetic secondary complications were ameliorated in some recipients, and quality of life studies showed significant gains after the transplant in all recipient categories.

CONCLUSIONS

Patient and graft survival rates have significantly improved over time as surgical techniques and immunosuppressive protocols have evolved. Eventually, islet transplants will replace pancreas transplants for suitable candidates, but currently pancreas transplants can be applied and should be an option at all stages of diabetes. Early transplants are preferable for labile diabetes, but even patients with advanced complications can benefit.

Diabetic retinopathy after combined kidney-pancreas transplantation

Diabetic retinopathy (DR) is amenable to good diabetic control; however, only successful pancreas transplantation can achieve sustained normoglycaemia. The aim of this long-term study was to examine the course of DR in insulin-dependent diabetic recipients of a simultaneous kidney and pancreas transplant (SPK). Successful SPK recipients (n = 46) and failed pancreas transplant with a functioning kidney transplant (n = 8) were assessed by baseline and regular post-transplant ophthalmic examinations (n = 432) for up to 10 yr after SPK. At the time of SPK (n = 108 eyes), the mean duration of diabetes was 25 +/- 7 yr, ten eyes were blind, and 79% of eyes had advanced DR that had panretinal laser (panretinal photocoagulation, PRP. Successful SPK recipients had normal glucose control with a mean HBA1C of 5.2 +/- 0.6%. DR remained stable in 75% of both the study and control groups, with no difference between groups. The DR mostly evolved towards inactive proliferative DR. After SPK, 14% of non-blind eyes showed improvement of DR, 76% remained stable and 10% progressed. Early vitreous haemorrhage occurred in 6.1% of eyes, and was related to established DR. Cataract of all types increased after transplantation (p < 0.01), which reduced visual acuity (VA) in affected eyes. The mean overall VA remained unchanged for the study duration. In summary, uremic patients from diabetic nephropathy had a high prevalence of severe proliferative DR and blindness at the time of presentation for SPK. This was subsequently stabilised to inactive proliferative DR by appropriate laser therapy followed by metabolic control achieved by SPK.