Segmental Pancreas Grafts Research Articles

Orthotopic placement of a segmental pancreas graft for transplant: a case report

Pancreas retransplantation has become more frequent and represents a technical challenge for surgeons. Knowledge of alternative surgical options could be useful in difficult cases. We present a case of brutal diabetes mellitus in a patient with severe vascular disease that underwent a third pancreas transplant. Difficulties in obtaining arterial inflow were solved utilizing the native splenic vessels, placing the graft in orthotopic position, and a combination of historical surgical techniques in pancreas transplantation; that is, segmental grafts and duct injection for exocrine management made transplantation successful.

Living Related Pancreas Transplantation Alone With Enteric Drainage in Japan: Case Report

In this study, we report a living donor partial pancreas transplantation using intraportal donor-specific leukocyte transfusion (DSLT). The recipient was a 38-year-old woman who had type I diabetes mellitus for 17 years. Hypoglycemia occurred 2 or 3 times per week. Her hemoglobin A 1c level was 9.0%, and she required 70 U of insulin almost every day. The donor was her 64-year-old father. The steroid-minimized immunosuppressive protocol included 1.5mg of thymoglobulin administered with a steroid bolus on days 0, 4, and 7 postoperatively. Steroids were never prescribed thereafter. Postoperative maintenance therapy included tacrolimus (FK506) and mycophenolate mofetil. In addition to these conventional approarches, we administered intraportal DSLT on days 0, 1, 4, and 7 after transplantation. The donor-specific leukocytes (40mL) had been separated from donor whole blood using an apheresis filter (Cellsorba EX; Asahi Kasei medical Co, Ltd, Tokyo, Japan). In the recipient operation, a segmental pancreas graft was transplanted into the right iliac cavity with enteric drainage with a pancreatic duct stent. Operation time was 6 hours. The postoperative course was uneventful. The patient was discharged on day 15 after transplantation. There was no acute rejection for six months after transplantation. The hemoglobin A 1c level recovered to 5.1% with 6 U of insulin per day. At immunologic analysis, only interleukine-10 cytokine production was elevated at 7 days after transplantation. At flow cytometry cross-match analysis, the immunoglobulin M antibody decreased from day 7 after transplantation. We conclude that intraportal DSLT may be an effective adjunct to a steroid-free regimen.

Effect of pancreas transplantation and immunosuppression on proinsulin secretion.

Insulin resistance and increased demand for insulin secretion occur after successful pancreas transplantation. To investigate the potential effects of immunosuppression and pancreas transplantation on fasting beta-cell function, we studied fasting proinsulin and 32,33 split proinsulin secretion cross-sectionally and longitudinally in segmental pancreatic graft recipients (SPx, n = 18); in whole-pancreas graft recipients (WPx, n = 13); in nondiabetic kidney transplant recipients (Kx, n = 14) and in normal subjects (Ns, n = 14). Basal insulin secretion rates were significantly increased in SPx 15.8 (1.7), WPx 24.4 (4.5) and Kx 22.1 (2.1) vs Ns 9.7 (1.6) pmol min(-1) l(-1), p < 0.05, mean (SEM). Total proinsulin, intact proinsulin and 32,33 split proinsulin concentrations were significantly higher in all the transplanted groups than in normal subjects (p < 0.05), whereas the total proinsulin to C-peptide ratio and the 32,33 split proinsulin ratio were higher in SPx than in WPx, Kx and Ns (< 0.05). In the longitudinal study, beta-cell function in terms of proinsulin secretion remained stable for 1 year. In conclusion, fasting glucose homeostasis in pancreas-kidney transplant recipients is obtained at the expense of increased proinsulin secretion and increased insulin secretion rates, primarily induced by immunosuppression. In segmental pancreas graft recipients, increased fasting proinsulin and 32,33 split proinsulin relative to the number of beta-cells transplanted indicate more stress on the residual beta-cell and therefore higher secretory demand than in whole pancreas transplant recipients.

Conversion of pancreas allograft rejection to acceptance by liver transplantation.

Liver allografts of PVG(RT1c)-->DA(RT1a) are spontaneously accepted, whereas pancreas, heart, and kidney allografts are rejected. Our previous studies have shown that simultaneous liver and pancreas transplantation prevents pancreas allograft rejection. The aim of this study was to examine the effect of liver transplantation on subsequent pancreas allografts and on ongoing pancreas rejection. Heterotopic, duct-ligated segmental pancreas grafts were transplanted into streptozotocin-induced diabetic recipients (60 mg/kg body weight i.p.) with or without orthotopic liver grafting at different times. Experimental design was as follows. Group 1 received PVG-->PVG pancreas syngrafts (n=6); group 2, PVG-->DA pancreas allografts (n=7); groups 3-5, PVG-->DA pancreas allografts followed by liver transplantation on day 2 (n=6), on day 4 (n=5), and on day 6 (n=5), respectively, group 6, PVG-->DA pancreas allografts after liver transplantation at 4 weeks (n=6). The results showed that pancreas allografts in group 2 were rejected from postoperative day 7 to 13. Liver transplantation prevented subsequent pancreas allograft rejection in group 6. Ongoing pancreas rejection was reversed by liver transplantation with subsequent graft acceptance in groups 3-5. Significant graft-infiltrating lymphocyte apoptosis was demonstrated at 2 weeks in pancreas transplants associated with liver grafting. Graft-versus-host disease was not detected in the pancreas recipients. We conclude that pancreas allografts in the PVG-->DA combination are rejected rapidly with median survival time of 9 days. Liver transplantation can protect subsequent pancreas grafts from rejection and reverse ongoing pancreas graft rejection with subsequent pancreatic acceptance. Graft-infiltrating lymphocyte apoptosis may be associated with the process of graft acceptance.

Pancreatic endocrine function in recipients of segmental and whole pancreas transplantation.

To determine potential abnormalities in beta-cell function after pancreas transplantation, the secretory capacity of the pancreatic grafts was assessed by measuring the glucose-potentiating effect on arginine-induced insulin secretion in recipients of cadaveric segmental (SPx; n = 8) and whole organ pancreas grafts (WPx; n = 6) and compared to that in nondiabetic kidney transplant recipients (Kx; n = 6) and normal controls (Ns; n = 7). alpha-Cell adaptation to increasing hyperglycemia and the glucagon response to arginine stimulation were also studied. The secretory capacity of the beta-cell to arginine-induced (5 g L-arginine) insulin secretion was measured at fasting plasma glucose and 15 and 30 mmol/L glucose. Insulin secretion was evaluated by the calculation of insulin secretion rates. Insulin sensitivity was markedly reduced in all three transplanted groups compared to that in normal subjects (P < 0.05). The prestimulation insulin secretion rate and maximal insulin secretion rate in response to hyperglycemia and arginine were significantly lower in SPx than in WPx, Kx, or Ns (P < 0.05). The incremental amount of insulin secreted in response to arginine was reduced by 40-70% in SPx depending on glycemia compared to that in all other groups (P < 0.05), among which there were no statistical differences. Both SPx and WPx demonstrated suppression of glucagon release in response to graded hyperglycemia, but failure to adequately suppress arginine-induced glucagon release. In conclusion, recipients of cadaveric segmental pancreas grafts display a markedly reduced maximal insulin secretory reserve capacity. This impairment was primarily due to an insufficient beta-cell mass. Taking the concomitant insulin resistance into account, recipients of a cadaver whole organ pancreas graft had an impaired insulin secretory reserve capacity as well.

Immunosuppressive antibody treatment prolongs graft survival in two murine models of segmental pancreas transplantation.

Successful pancreas transplantation requires the suppression of both allograft rejection and recurrence of autoimmune disease. In order to study treatments to suppress these two responses, separate models were developed for pancreas allograft rejection and autoimmune disease. In the first model, the diabetic state was induced with streptozotocin in CBA mice prior to the transplantation of pancreas grafts from BALB/c donors. In the absence of autoimmune disease, control mice rejected their grafts in 26 days (median). Antibody treatments (anti-lymphocyte serum and anti-CD4) significantly prolonged allograft survival beyond this time, but not to the extent we have previously reported in the heart graft model. NOD/Lt mice spontaneously developed autoimmune diabetes, and recurrence of disease was seen in isografts at 9.5 days (median). Antibody treatments significantly delayed disease recurrence, with anti-CD4 being the most effective. Heart allografts (CBA donors) in NOD/Lt recipients were rejected within 17 days (median), and the anti-CD4 treatment had a moderate effect in delaying graft survival (median 28 days). Anti-lymphocyte serum did not prolong graft survival. Thus antibody treatment was effective in delaying both rejection and the recurrence of autoimmune disease in segmental pancreas grafts. However, the same doses were not effective in delaying heart rejection in the NOD/Lt model, so it would appear that treatments which inhibit autoimmune disease may not prevent allograft rejection.

Pancreatic transplantation with delayed duct occlusion versus bladder drainage: long-term results

Between April 1985 and August 1990 a total of 51 combined pancreas kidney transplants and 6 single pancreas transplants were performed in 51 Type 1 (insulin - dependent) diabetic patients suffering from end-stage diabetic nephropathy and three patients with proliferative retinopathy. In 17 transplants the pancreatic duct was occluded with a mean delay of 53 days (Group 1). Because of a high incidence of local complications associated with a prolonged hospitalization this technique was abandoned despite favourable results: The actual survival rates for patients, pancreas and renal allografts at 1 year are 94%, 72% and 93%, respectively. From 1987 a total of 39 consecutive segmental pancreas grafts were anastomosed with the urinary bladder (Group 2). Pancreatic secretions were temporarily drained to the exterior in all patients via a duct catheter. Monitoring of the exocrine function including pancreatic secretion cytology and pancreatic secretion neopterin excretion proved to be reliable rejection markers. Survival rates at 1 year were calculated to be 90%, 74% and 89% for all patients, pancreas grafts and renal grafts. Apart from local complications in group I which did not cause any graft loss, the surgical complication rate was comparably low in both groups.

Rehabilitation and quality of life in diabetic patients after successful pancreas-kidney transplantation

Twenty-seven Type I diabetic patients in end-stage renal failure were followed after combined pancreas-kidney transplantation. All patients received duct-occluded segmental pancreas grafts. Clinical progression of extrarenal diabetic complications was studied in 11 patients with long-term functioning pancreatic and renal transplants (Group 1), and in 16 patients who had lost pancreatic graft function, but retained renal graft function (Group 2). Pretransplant, extrarenal diabetic complications were equally distributed in the two groups. In the follow-up period, however, the progress of these complications was less severe in patients with functioning pancreatic transplants. No differences were found between the groups concerning rehabilitation, working capacity, need of help or hospital admittance. It is suggested that pancreas transplantation performed in an earlier stage of diabetes before serious complications have developed, would probably improve rehabilitation and quality of life in these patients.

Pancreatic transplantation: The cambridge experience

In contrast to heterotopic pancreas transplantation and conventional insulin therapy the paratopic positioning of a segmental pancreas graft provides physiological endocrine hormone delivery into the portal venous circulation. Metabolic studies performed on previously insulin dependent diabetic patients with renal failure with functioning paratopic pancreas transplants and heterotopic kidney grafts from the same donor showed near normal day to day glucose control with normal fasting glucose levels and normal HbA 1 values. Hyperinsulinaemia was not seen in these patients. The effect of denervation of the pancreatic graft on the entero-insular axis and its influence on the islets were investigated. The incretin effect was preserved indicating a significant hormonal stimulation of the enteroinsular axis.

Experimental pancreatic allotransplantation in large animals. The role of donor kidney and cyclosporine in modifying rejection.

Experiments were carried out in outbred dogs and pigs to evaluate the relative immunogenicity of pancreatic islets and segmental pancreas grafts, and whether these could be ameliorated by transplanting a kidney simultaneously from the same donor animal. Various immunosuppressive regimens were also studied. Pancreatic islet allografts never normalized blood glucose in totally pancreatectomized recipients despite the use of cyclosporine (CsA) in high doses (40 mg/kg/day) and the simultaneous transplantation of a kidney from the same donor. These grafts which never "took" contrast sharply with the experience of pancreatic islet autografts prepared in the same way and inoculated into the spleen, which in all nine instances normalized blood glucose in pancreatectomized recipients. Segmental transplants were performed in swine with duct drainage into the jejunum. Totally pancreatectomized pigs died at 7.8 +/- 1.0 days. In recipients suppressed with low-dose azathioprine (Az) and prednisone (Pred) pancreas grafts alone were rejected in 12.9 +/- 10 days. Synchronous pancreas and kidney transplants treated similarly extended the mean survival of pancreatic grafts to 20 +/- 10 days--which, however, was not significant (P less than 0.1 greater than 0.05). Mean survival time of pancreatic grafts in recipients receiving CsA at 20 mg/kg/day and prednisone 1 mg/kg/day was 14 +/- 6.3 days. The combination of CsA 20 mg/kg/day, Az 2 mg/kg/day, and Pred 1 mg/kg/day prolonged the mean survival time to 39.8 +/- 22 days. These results allow us to conclude that: crude preparations of islet tissue invariably capable of normalizing blood sugar at day 4 when used as autografts failed to "take" despite the existence of alternative sources of antigen present in a well vascularized kidney from the same donor, and despite very high dosages of CsA; triple immunosuppressive therapy had synergistic effects on pancreatic allograft survival; and simultaneous transplantation of kidney and pancreas had little effect on survival times of the pancreas or the kidney.

The postoperative course and quantitative aspects of rat islet and segmental pancreas isografts

Duct-ligated segmental pancreas transplants with systemic venous drainage were compared to intrahepatic islet grafts for β-cell mass (proportional to tissue insulin content) and function in diabetic Lewis rats. Rats were serially killed to measure insulin in the segmental pancreas grafts and in the liver of the islet recipients. Segmental pancreas weight was maximum and insulin concentration and content lowest ( P < 0.05) on Day 3 when acute inflammation was present. At 21 days, there was no inflammation, and graft weight had decreased, but not to Day 0 level because of normal growth; insulin concentration was similar on Days 21 and 0. At 3 months, moderate fibrosis of the graft was present, but both total insulin and insulin concentration had increased ( P < 0.05). In the recipients of islet grafts, total insulin in the liver on Day 1 was only 43% of that contained in the original islet preparation, but by 3 months the insulin content in the liver had increased to that transplanted. IVGTT K values were similar in normal rats (−3.5 ± 0.7%) and in recipients of segmental pancreas (−4.5 ± 1.6%) and islet (−4.0 ± 1.5%) grafts at 3 months post transplant. Acute segmental graft pancreatitis resolved, follwed by an increase in β-cell mass. Islet cell damage during transplantation is either reversible or residual viable islets proliferate, and provide metabolic control equivalent to segmental pancreas transplants, even though the final β-cell mass is less.

The use of cyclosporin A in clinical organ grafting.

Experiments in animals with organ allografts showed that Cyclosporin A (CyA) was an extremely powerful immunosuppressant with a good therapeutic index. A pilot study of the drug in human recipients of renal allografts revealed an unexpected side effect, nephrotoxicity, which made care of patients difficult. Following a policy of deliberate hydration of patients in the perioperative phase and withholding CyA until diuresis was occurring in the graft, excellent results have been obtained in clinical practice. An 82% actuarial functional survival at both one and two years has been obtained in the 59 patients treated with this protocol. A multicenter trial is now in progress in eight centers in Europe, comparing CyA used in the manner described above with conventional azathioprine and steroids. CyA has also been used in 17 recipients of liver allografts, ten of whom are still alive and 11 recipients of segmental pancreatic allografts, one of whom remains off insulin after two and a quarter years. Sudden graft failure occurred between three months and two years in three patients whose pancreatic duct had been occluded. The authors' most recent segmental pancreas graft has been drained into a long roux loop without complications. The main objective in the use of this drug is to obtain consistent immunosuppression without nephrotoxicity. It is possible that maintaining blood level between defined limits would improve results.