Short- and long-term surgical outcomes of total pancreatectomy with islet autotransplantation: A comparative analysis of surgical technique and intraoperative heparin dosing to optimize outcomes.

BACKGROUND: Total pancreatectomy with islet autotransplantation (TP-IAT) is an uncommon surgical procedure with unique perioperative management. We evaluated the short- and long-term morbidity and mortality of TP-IAT to optimize surgical technique and heparin dosing during islet autotransplantation. METHODS: Eighty patients with chronic pancreatitis undergoing TP-IAT were reviewed. Primary outcome was to evaluate morbidity and mortality based on operative technique: classic (resection of antrum) vs pylorus-preserving. Secondary outcome was to evaluate the effect of heparin dosing (<60 vs ≥ 60 units/kg) during islet autotransplantation on postoperative hemorrhage and portal vein thrombosis (PVT) rates. RESULTS: There was no 90-day mortality, and median length of stay was 9 days. All patients underwent an open operation with 53 (66%) pylorus-preserving resections. The 30-day morbidity rate was 39%, with no difference between operative technique (p = 0.82). The median dose was different for each heparin group (<60: 52 units/kg vs ≥ 60: 66 units/kg, p < 0.0001). No difference was observed in postoperative hemorrhage rates between heparin groups (<60: 9% vs ≥ 60: 9%, p = 0.97), with no known incidence of PVT. Median follow-up was 36 months (IQR, 14-71). Morbidity >30 days after TP-IAT was 43% with a higher rate in the pylorus-preserving group (55% vs 15%, p < 0.0001), mainly attributed to marginal ulcer formation (15% vs 0%, p = 0.03). CONCLUSIONS: A classic TP-IAT technique should be universally adopted to achieve optimal outcomes, particularly to prevent the formation of marginal ulcers. When considering PVT versus postoperative hemorrhage risk, a lower heparin dose nearing 50 units/kg is optimal. These findings highlight potential areas for future improvement.

Diabetes-free survival after extended distal pancreatectomy and islet auto transplantation for benign or borderline/malignant lesions of the pancreas.

Islet autotransplant is particularly attractive to prevent diabetes after extended pancreatectomy for benign or borderline/malignant pancreas disease. Between 2008 and 2018, 25 patients underwent left extended pancreatectomy (>60%) and islet autotransplant for a neoplasm located in the pancreatic neck or proximal body. Overall, disease-free and diabetes-free survivals were estimated and compared with those observed in 68 nondiabetic patients who underwent distal pancreatectomy for pancreatic neoplasms without islet autotransplant. Median follow-up was 4 years. We observed no deaths and a low morbidity (nonserious procedure-related complications in 2 of 25 patients). Patient and insulin-independent survival rates at 4 years were 100% and 96%, respectively. Glucose homeostasis remained within a nondiabetic range at all times for 19 (73%) of 25 patients. Preoperative glycemic level and insulin resistance were major predictors of diabetes development in these patients. Patients undergoing islet autotransplant had a longer diabetes-free survival than did patients without islet autotransplant (P = .04). In conclusion, islet autotransplant after extended pancreatic resection for neoplasms is a safe and successful procedure for preventing diabetes.

Relaparotomy for a pancreatic fistula after a pancreaticoduodenectomy: a comparison of different surgical strategies.

INTRODUCTION: A relaparotomy for a pancreatic fistula (PF) after a pancreaticoduodenectomy (PD) is a formidable operation, and the appropriate treatment of anastomotic leakage is under debate. The objective of this study was to compare the outcomes of different strategies in managing the pancreatic remnant during a relaparotomy for PF after a PD. METHODS: In this retrospective study on prospectively collected data, 669 PD were performed between 2004 and 2011. The study group comprised 31 patients requiring a relaparotomy, because of delayed haemorrhage (n = 19) or sepsis (n = 12). The pancreatic stump was treated either using pancreas-preserving techniques (simple drainage or duct occlusion) or completion of a pancreatectomy (CP). In 2008, autologous islet transplantation (AIT) was introduced for endocrine tissue rescue of CP. RESULTS: The mortality rate, blood loss and transfusion requirement were similar for all techniques. Patients undergoing a CP required a further relaparotomy less frequently than patients with pancreas preservation (7% versus 59%, P < 0.01), and the intensive care unit (ICU) stay was reduced after CP (P = 0.058). PF persisted at discharge in 66% of patients after pancreas-preserving techniques. AIT was associated with CP in 7 patients, of whom one died post-operatively. Long-term graft function was maintained in four out of six surviving patients, with one insulin-independent patient at 36 months after transplantation. CONCLUSIONS: When a PF requires a relaparotomy, CP has become our favoured technique. AIT can reduce the metabolic impact of the procedure.

Morbidity of total pancreatectomy with islet cell auto-transplantation compared to total pancreatectomy alone.

BACKGROUND: In pancreatitis, total pancreatectomy (TP) is an effective treatment for refractory pain. Islet cell auto-transplantation (IAT) may mitigate resulting endocrinopathy. Short-term morbidity data for TP + IAT and comparisons with TP are limited. METHODS: This study, using 2005-2011 National Surgical Quality Improvement Program data, examined patients with pancreatitis or benign neoplasms. Morbidity after TP alone was compared with that after TP + IAT. RESULTS: In 126 patients (40%) undergoing TP and 191 (60%) patients undergoing TP + IAT, the most common diagnosis was chronic pancreatitis. Benign neoplasms were present in 46 (14%) patients, six of whom underwent TP + IAT. Patients in the TP + IAT group were younger and had fewer comorbidities than those in the TP group. Despite this, major morbidity was more frequent after TP + IAT than after TP [n = 79 (41%) versus n = 36 (29%); P = 0.020]. Transfusions were more common after TP + IAT [n = 39 (20%) versus n = 9 (7%); P = 0.001], as was longer hospitalization (13 days versus 9 days; P < 0.0001). There was no difference in mortality. CONCLUSIONS: This study is the only comparative, multicentre study of TP and TP + IAT. The TP + IAT group experienced higher rates of major morbidity and transfusion, and longer hospitalizations. Better data on the longterm benefits of TP + IAT are needed. In the interim, this study should inform physicians and patients regarding the perioperative risks of TP + IAT.

Insulin replacement therapy in patients with type 1 diabetes by isolated pancreatic islet transplantation.

Diabetes mellitus is a metabolic disease characterized by chronic hyperglycemia which causes micro- and macrovascular complications. A significant increase in diabetes morbidity rate has been observed. It is estimated that in year 2030 there will be 552 million diabetics worldwide. Type 1 diabetes requires lifelong treatment with insulin. The only available treatment of diabetes restoring physiological glucose metabolism is transplantation of pancreatic beta cells in form of pancreas or isolated pancreatic islets transplantation. The treatment restores normoglycemia and reduces chances of complications of diabetes. Over the past 10 years there has been significant progress in the development of the islet transplantation procedure. Constant improvement of the method, in particular the development of islets isolation and sourcing techniques, shows promise. According to the Collaborative Islet Transplant Registry in 1999-2009, there have been performed 1,072 allotransplantations. This paper summarizes the indications and contraindications for the procedure, the transplantation process, as well as the surgical procedure and immunosuppressive treatment. The review presents problems related to pancreatic islet cells transplantation and standard scheme of immunosuppressive treatment, requiring a solution.

Systematic review and meta-analysis: islet autotransplantation after pancreatectomy for minimizing diabetes.

OBJECTIVE: Islet autotransplantation (IAT) may decrease the morbidity and mortality of postpancreatectomy diabetes mellitus. The current systematic review and meta-analysis examined the rate of insulin independence (II) and mortality after IAT post-total (TP) or partial pancreatectomy (PP). METHODS: Ovid MEDLINE, EMBASE, Web of Science, SCOPUS and reference lists were searched until 31 January 2011. Eligible studies enrolled adult patients with IAT post-TP or PP, regardless of study design, sample size and language. Two investigators identified eligible studies and extracted data independently. From each study, 95% confidence intervals (CIs) were estimated and pooled using random effects meta-analysis. RESULTS: Fifteen observational studies were eligible (11 IAT post-TP, two post-PP and two including both). The II rates for IAT post-TP at last follow-up and transiently during the study were 4·62 per 100 person-years (95% CI: 1·53-7·72) and 8·34 per 100 person-years (95% CI: 3·32-13·37), respectively. In the later group, patients achieved transient II lasting 15·57 months (95% CI: 10·35-20·79). The II rate at last follow-up for IAT post-PP was 24·28 per 100 person-years (95% CI: 0·00-48·96). Whereas the 30-day mortality for IAT post-TP and post-PP was 5% (95% CI: 2-10%) and 0, respectively, the long-term mortality was 1·38 per 100 person-years (95% CI: 0·66-2·11) and 0·70 per 100 person-years (95% CI: 0·00-1·80) respectively. CONCLUSIONS: IAT postpancreatectomy offers some patients a chance for insulin independence. Better data reporting are essential to establish the risks and benefits of IAT after pancreatic surgery.

Laparoscopic Total Pancreatectomy With Islet Autotransplantation and Intraoperative Islet Separation as a Treatment for Patients With Chronic Pancreatitis.

Importance: Pain management of patients with chronic pancreatitis (CP) can be challenging. Laparoscopy has been associated with markedly reduced postoperative pain but has not been widely applied to total pancreatectomy with islet autotransplantation (TPIAT). Objective: To examine the feasibility of using laparoscopic TPIAT (L-TPIAT) in the treatment of CP. Design, Setting, and Participants: Thirty-two patients with CP presented for TPIAT at a tertiary hospital from January 1, 2013, through December 31, 2015. Of the 22 patients who underwent L-TPIAT, 2 patients converted to an open procedure because of difficult anatomy and prior surgery. Pain and glycemic outcomes were recorded at follow-up visits every 3 to 6 months postoperatively. Main Outcomes and Measures: Operative outcomes included operative time, islet isolation time, warm ischemia time, islet equivalent (IE) counts, estimated blood loss, fluid resuscitation, and blood transfusions. Postoperative outcomes included length of stay, all-cause 30-day readmission rate, postoperative complications, mortality rate, subjective pain measurements, opioid use, random C-peptide levels, insulin requirements, and glycated hemoglobin level. Results: Of the 32 patients who presented for TPIAT, 20 underwent L-TPIAT (8 men and 12 women; mean [SD] age, 39 [13] years; age range, 21-58 years). Indication for surgery was CP attributable to genetic mutation (n = 9), idiopathic pancreatitis (n = 6), idiopathic pancreatitis with pancreas divisum (n = 3), and alcohol abuse (n = 2). Mean (SD) operative time was 493 (78) minutes, islet isolation time was 185 (37) minutes, and warm ischemia time was 51 (62) minutes. The mean (SD) IE count was 1325 (1093) IE/kg. The mean (SD) length of stay was 11 (5) days, and the all-cause 30-day readmission rate was 35% (7 of 20 patients). None of the patients experienced postoperative surgical site infection, hernia, or small-bowel obstruction, and none died. Eighteen patients (90%) had a decrease or complete resolution of pain, and 12 patients (60%) no longer required opioid therapy at a median follow-up period of 6 months. Postoperative random insulin C-peptide levels were detectable in 19 patients (95%) at a median follow-up of 10.4 months. At a median follow-up of 12.5 months, 5 patients (25%) were insulin independent, whereas 9 patients (45%) required 1 to 10 U/d, 5 patients (25%) required 11 to 20 U/d, and 1 patient (5%) required greater than 20 U/d of basal insulin. The mean (SD) glycated hemoglobin level was 7.4% (0.5%). Conclusions and Relevance: This study represents the first series of L-TPIAT, demonstrating its safety and feasibility. Our approach enables patients to experience shorter operative times and the benefits of laparoscopy, including reduced length of stay and quicker opioid independence.

Five-year follow-up after clinical islet transplantation.

Islet transplantation can restore endogenous beta-cell function to subjects with type 1 diabetes. Sixty-five patients received an islet transplant in Edmonton as of 1 November 2004. Their mean age was 42.9 +/- 1.2 years, their mean duration of diabetes was 27.1 +/- 1.3 years, and 57% were women. The main indication was problematic hypoglycemia. Forty-four patients completed the islet transplant as defined by insulin independence, and three further patients received >16,000 islet equivalents (IE)/kg but remained on insulin and are deemed complete. Those who became insulin independent received a total of 799,912 +/- 30,220 IE (11,910 +/- 469 IE/kg). Five subjects became insulin independent after one transplant. Fifty-two patients had two transplants, and 11 subjects had three transplants. In the completed patients, 5-year follow-up reveals that the majority ( approximately 80%) have C-peptide present post-islet transplant, but only a minority ( approximately 10%) maintain insulin independence. The median duration of insulin independence was 15 months (interquartile range 6.2-25.5). The HbA(1c) (A1C) level was well controlled in those off insulin (6.4% [6.1-6.7]) and in those back on insulin but C-peptide positive (6.7% [5.9-7.5]) and higher in those who lost all graft function (9.0% [6.7-9.3]) (P < 0.05). Those who resumed insulin therapy did not appear more insulin resistant compared with those off insulin and required half their pretransplant daily dose of insulin but had a lower increment of C-peptide to a standard meal challenge (0.44 +/- 0.06 vs. 0.76 +/- 0.06 nmol/l, P < 0.001). The Hypoglycemic score and lability index both improved significantly posttransplant. In the 128 procedures performed, bleeding occurred in 15 and branch portal vein thrombosis in 5 subjects. Complications of immunosuppressive therapy included mouth ulcers, diarrhea, anemia, and ovarian cysts. Of the 47 completed patients, 4 required retinal laser photocoagulation or vitrectomy and 5 patients with microalbuminuria developed macroproteinuria. The need for multiple antihypertensive medications increased from 6% pretransplant to 42% posttransplant, while the use of statin therapy increased from 23 to 83% posttransplant. There was no change in the neurothesiometer scores pre- versus posttransplant. In conclusion, islet transplantation can relieve glucose instability and problems with hypoglycemia. C-peptide secretion was maintained in the majority of subjects for up to 5 years, although most reverted to using some insulin. The results, though promising, still point to the need for further progress in the availability of transplantable islets, improving islet engraftment, preserving islet function, and reducing toxic immunosuppression.

Natural history of kidney graft survival, hypertrophy, and vascular function in end-stage renal disease type 1 diabetic kidney-transplanted patients: beneficial impact of pancreas and successful islet cotransplantation.

OBJECTIVE: Diabetes, hypertension, infections, and nephrotoxicity of certain immunosuppressive drugs (i.e., calcineurin inhibitors) can reduce functional survival of the kidney graft. Our aim was to evaluate survival, hypertrophy, and vascular function of the kidney graft in end-stage renal disease (ESRD) type 1 diabetic patients after transplant. RESEARCH DESIGN AND METHODS: The study population consisted of 234 ESRD type 1 diabetic patients who underwent kidney-pancreas (KP; 166 patients), successful kidney-islet (KI-s; 24 patients), and kidney (KD; 44 patients) transplant. Kidney size, graft survival, vascular function, and microalbuminuria were evaluated prospectively yearly for 6 years. Sixty-eight protocol kidney biopsies were performed routinely between 1993 and 1998 cross-sectionally (3.2 +/- 0.3 years from kidney transplant). RESULTS: The KP and KI-s groups had better cumulative kidney graft survival at 6 years than did the KD group (KP: 73%; KI-s: 86%; KD: 42%, P < 0.01). The KP group but not the KI-s/KD groups showed a persistent kidney graft hypertrophy up to 6 years of follow-up. A significant increase in creatinine levels from baseline to year 6 was evident in the KD group (1.58 +/- 0.08 to 2.78 +/- 0.44 mg/dl, P < 0.05) but not in the KP/KI-s groups. The KP/KI-s groups only showed a reduction of renal resistance index from baseline to year 6 (KP at baseline: 0.74 +/- 0.01 to 0.68 +/- 0.01%, P < 0.01; KI-s at baseline: 0.72 +/- 0.02 to 0.69 +/- 0.02%, P < 0.05). At year 6, an increase from baseline in urinary albumin excretion was observed only in the KD group (31.4 +/- 9.0 to 82.9 +/- 33.6 mg/l, P < 0.05). Preliminary data suggested that graft nitric oxide (NO) expression was higher in the KP/KI-s groups than in the KD group (data not shown). CONCLUSIONS: In ESRD type 1 diabetic patients, KP and KI-s compared with KD resulted in enhanced kidney graft survival, hypertrophy, and vascular function.

Logistics and transplant coordination activity in the GRAGIL Swiss-French multicenter network of islet transplantation.

BACKGROUND: Since the Edmonton trial in 2000, increasing numbers of transplant centers have been implementing islet transplantation programs. Some institutions have elected to associate in multicenter networks, such as the Swiss-French GRAGIL (Groupe Rhin-Rhône-Alpes-Genève pour la Transplantation d'Ilots de Langerhans) consortium. METHODS: All pancreata offers to the University of Geneva Cell Isolation and Transplantation Center from within the network in 2002 and 2003 were reviewed. Islet preparations were attributed to the most suitable recipient on a centrally managed waiting list. All shipments were performed by ambulance in less than 5 hr. RESULTS: Over the period of study, 260 pancreata were offered, from a total of 1,304 cadaveric donors in the four allocation regions (20%). Fifty-two patients were on the waiting list at any time during this 2-year period. The percentage of organs offered varied in the range of 0.5% to 42%, depending on region of origin, with a correlation with number of patients on the waiting list in each region. Of these, 104 (40%) were accepted for processing. Ninety-two pancreata were actually processed, resulting in 42 islet preparations being transplanted. The number of international equivalents of transplanted preparations was 378,500+/-16,000 versus 165,400+/-15,400 (P<0.0001) for nontransplanted preparations. Total cold ischemia time was 6+/-0.3 hr for transplanted preparations versus 6.7+/-0.4 hr for nontransplanted preparations (not significant). CONCLUSIONS.: A high rate of pancreas offers, successful isolation, and islet transplantation can be achieved in multicenter networks such as GRAGIL. Such an approach can expand both the donor pool and the recipient population.

Long-term beneficial effect of islet transplantation on diabetic macro-/microangiopathy in type 1 diabetic kidney-transplanted patients.

OBJECTIVE: Our aim was to evaluate the long-term effects of transplanted islets on diabetic macro-/microangiopathy in type 1 diabetic kidney-transplanted patients. RESEARCH DESIGN AND METHODS: A total of 34 type 1 diabetic kidney-transplanted patients underwent islet transplantation and were divided into two groups: successful islet-kidney transplantation (SI-K; 21 patients, fasting C-peptide serum concentration >0.5 ng/ml for >1 year) and unsuccessful islet-kidney transplantation (UI-K; 13 patients, fasting C-peptide serum concentration <0.5 ng/ml). Patients cumulative survival, cardiovascular death rate, and atherosclerosis progression were compared in the two groups. Skin biopsies, endothelial dependent dilation (EDD), nitric oxide (NO) levels, and atherothrombotic risk factors [von Willebrand factor (vWF) and D-dimer fragment (DDF)] were studied cross-sectionally. RESULTS: The SI-K group showed a significant better patient survival rate (SI-K 100, 100, and 90% vs. UI-K 84, 74, and 51% at 1, 4, and 7 years, respectively, P = 0.04), lower cardiovascular death rate (SI-K 1/21 vs. UI-K 4/13, chi(2) = 3.9, P = 0.04), and lower intima-media thickness progression than the UI-K group (SI-K group: delta1-3 years -13 +/- 30 micro m vs. UI-K group: delta1-3 years 245 +/- 20 micro m, P = 0.03) with decreased signs of endothelial injuring at skin biopsy. Furthermore, the SI-K group showed a higher EDD than the UI-K group (EDD: SI-K 7.8 +/- 4.5% vs. UI-K 0.5 +/- 2.7%, P = 0.02), higher basal NO (SI-K 42.9 +/- 6.5 vs. UI-K 20.2 +/- 6.8 micro mol/l, P = 0.02), and lower levels of vWF (SI-K 138.6 +/- 15.3 vs. UI-K 180.6 +/- 7.0%, P = 0.02) and DDF (SI-K 0.61 +/- 0.22 vs. UI-K 3.07 +/- 0.68 micro g/ml, P < 0.01). C-peptide-to-creatinine ratio correlated positively with EDD and NO and negatively with vWF and DDF. CONCLUSIONS: Successful islet transplantation improves survival, cardiovascular, and endothelial function in type 1 diabetic kidney-transplanted patients.

Immunotoxicological effects of streptozotocin and alloxan: in vitro and in vivo studies.

Streptozotocin (STZ) and alloxan (ALX), widely used to induce diabetes in experimental animals, have different structures and mechanisms of action. We investigated those effects of these drugs on the immune system that might influence engraftment efficiency and graft survival in transplantation models, and their cytotoxicity on hematopoietic cell lines. We used the minimum dose to induce diabetes in a mouse, i.e. 180 mg/kg i.v. STZ and 75 mg/kg i.v. ALX. Both groups exhibited significant decrease in body weight during 4 days post-treatment as compared to controls. We found that blood glucose in ALX-injected mice increased faster than in STZ-injected mice. The total number of recovered splenocytes was lower in STZ-injected animals than in ALX-injected animals. The survival periods of rat islet grafts in recipient mice were longer and more diverse in STZ-injected recipients (7-24 days) compared to ALX-injected recipients (6-7 days). The in vitro study showed that ALX was less cytotoxic in cell lines with IC50 values of 2809, 3679 and >4000 µg/ml for HL60, K562 and C1498 cells respectively. STZ was more toxic, especially in HL60 cells, with IC50 values of 11.7, 904 and 1024 µg/ml for HL60, K562 and C1498 cells respectively. Furthermore, in response to concanavalin A (Con-A), splenocytes from STZ-injected mice produced higher amounts of interferon-gamma (IFN-γ) than those from ALX-injected mice. In conclusion, STZ was more cytotoxic than ALX in vitro and in vivo. STZ caused lymphocytopenia, which may result in longer graft survival in STZ-treated animals than in ALX-treated animals.

Survival and function of purified islets in the omental pouch site of outbred dogs.

The aims of this study were to devise an omental pouch site for islet implantation in a preclinical large animal and to compare the function of islets engrafted to this site with islets implanted into the spleen. Highly purified islets were isolated from outbred mongrel dogs, then grafted into totally pancreatectomized outbred recipients. Autografts of islets were implanted into a greater omental pouch (group [gp] 1, n = 12) or into the spleen by venous reflux (gp 2, n = 12). Allografts of single donor islets were implanted into the omental pouch (gp 3) of dogs that received CsA (n = 9) or untreated controls (n = 3). The threshold islet mass that consistently reversed diabetes in gp 1 was 10 microliters/kg, which exceeded by 2.5-fold that required in gp 2. Normoglycemia was induced and maintained for 2 months in 6 gp 1 and 8 gp 2 dogs. At IVGTT, the K value (decline in glucose, %/min) was 1.3 +/- 0.4 in gp 1 versus 1.5 +/- 0.2 in gp 2 (P > 0.2). Peripheral venous insulin levels were significantly lower (P < 0.01) in gp 1. Omentectomy (gp 1) or splenectomy (gp 2) induced prompt hyperglycemia. All gp 3 dogs (received > 10 microliters/kg) were initially normoglycemic: grafts of untreated controls failed at 4.2 +/- 1.8 days. In 1 CsA-treated dog the graft failed for technical reasons; normoglycemia persisted in the other 8 for 10, 15, and 21 days, and in 5 instances for > 30 days. When CsA therapy was stopped at 30 days, normoglycemia persisted for 34 +/- 9.5 days. We conclude that purified islets restore normoglycemia after implantation into the omental pouch of diabetic dogs. Compared with intrasplenic islet implantation, an increased graft volume is required and insulin levels are lower.

Endocrine and exocrine function of pancreatic fragments autotransplanted into hepatic parenchyma.

We studied the use of hepatic parenchyma as a recipient site for pancreatic fragment transplantation. Endocrine and exocrine pancreatic functions were evaluated following pancreatic autotransplantation in 26 mongrel dogs that had undergone total pancreatectomy. The endocrine function of the pancreatic tissue transplanted to hepatic parenchyma was significantly inferior to that of normal controls. Cholecystic bile amylase concentrations were markedly elevated in six dogs that had been implanted with pancreatic fragments in their hepatic parenchyma and had survived more than 2 months. Also, choledochal bile amylase concentrations increased significantly following pancreozymin-secretion (PS) injection. In contrast, cholecystic bile amylase concentrations in normal dogs were low and choledochal bile amylase concentrations did not respond to a PS load. Histological examination of pancreatic autografts in hepatic parenchyma revealed marked proliferation of exocrine tissue with abundant zymogen granules and reconstruction of pancreatic lobules with a few islets.

Combination therapy with anti-ICOS and cyclosporine enhances cardiac but not islet allograft survival.

The blockade of costimulatory signals is a powerful strategy to prevent allograft rejection and facilitate transplantation tolerance. In recent years, a series of novel costimulatory molecules have been identified, including an inducible costimulatory molecule (ICOS). To date, little has been uncovered regarding the therapeutic potential of blocking ICOS signaling in the setting of transplantation. In a fully MHC-mismatched mouse model, we studied the effect of blocking ICOS signaling using a specific monoclonal antibody (anti-ICOS mAb) in combination with cyclosporine on cardiac and islet allograft survival. We demonstrated that combined treatment with anti-ICOS mAb and cyclosporine can induce long-term graft acceptance in cardiac but not islet allografts, suggesting that the type of transplanted tissue significantly influences the immunologic patterns of graft acceptance or rejection in this model.

Pancreas and islet cell transplantation: now and then.

Pancreas transplantation currently can be offered with the same probability of success as other solid organ transplants. In diabetic uremic recipients of kidney transplants, the addition of a pancreas is routine in many centers. For selected patients with labile diabetes and hypoglycemia unawareness, a successful pancreas transplant can dramatically improve quality of life. Islet transplantation is an alternative to pancreas transplantation that can reduce surgical morbidity, but is much less successful at the moment. The theoretical, immunological advantages of islet transplantation have not yet been realized. Part of the problem lies in the reduced beta cell mass that occurs with organ dispersal and islet purification. Diabetogenic immunosuppressants need to be eliminated in order to allow optimal function of what is engrafted. The immunosuppressants (eg, mycophenolate mofetil, rapamycin) give this possibility. Whether islet transplantation will replace pancreas transplantation remains problematic. Ultimately, and neither should be needed for Type I diabetes, since autoimmune diseases should be preventable by appropriate manipulation of the immune system in those identified at risk. Our personal goals as transplanters should be obsolescence.

The effect of FasL expression on pancreatic islet allografts.

OBJECTIVE: To investigate the immune privilege induced by the Fas ligand (FasL) expressed by cotransplanted testicular Sertoli cells in islet allografts, and the effect of FasL gene transfection on islet cells in pancreatic islet allografts. METHODS: Allogeneic islets and testicular cells were cotransplanted into diabetic recipients. Pancreatic islets were infected with the recombinant adenovirus, AdV-FasL, and transplanted into diabetic recipients. Allograft survival, islet function, apoptosis of infiltrative lymphocytes in allografts and gene transfected islet allografts were analyzed. RESULTS: All animals receiving islet allograft alone returned to a diabetic state in a few days (mean survival time 6.3 +/- 0.6 days). When the quantity of testicular cells cotransplanted with islets increased to 1 x 10(7), all animals remained normoglycemic throughout the follow-up period (60 days). FasL expression by cotransplanted Sertoli cells induced apoptosis of activated lymphocytes. Rejection of allografts in the FasL gene transfer group was accelerated and allograft survival was shortened to 3.4 +/- 0.2 days (P < 0.05). Pancreatic islets infected with AdV-FasL demonstrated positive staining for FasL at 24h after transplantation, with increased intensity at 48h. Apoptosis assays of pancreatic islet allografts at 24h and 48h revealed apoptosis of transfected islets. CONCLUSIONS: FasL-expressing testicular Sertoli cells can induce apoptosis of activated lymphocytes. Cotransplantation of testicular cells allows long-term survival of allogeneic islets because of immune privilege, but the direct expression of FasL on islet allografts infected with AdV-FasL accelerates islet rejection via islet apoptosis and granulocyte infiltration.

The effect of FasL gene transfer to islet cells on pancreatic islet allografts.

OBJECTIVE: To investigate the effect of FasL gene transfer to islet cells on pancreatic islet allografts. METHODS: A recombinant and replication-deficient type-5 adenovirus encoding murine FasL (AdV- FasL) was constructed by the method of calcium phosphate precipitation. Pancreatic islets were infected with the recombinant adenovirus AdV-FasL, and transplanted into diabetic recipients. FasL expression was detected by RT-PCR and immunohistochemistry. The survival of allografts and the apoptosis of gene transferred islet allografts were analyzed. RESULTS: All animals receiving islet allograft alone returned to a diabetic state by several days (mean survival time 6.3+/-0.6 days). Compared with the control group, no delayed rejection and prolonged survival of allografts were observed in the group of FasL gene transfer. The rejection was accelerated and the allograft survival was shortened to 3.4+/-0.2 days (P<0.05). Pancreatic islets infected with AdV- FasL demonstrated positive staining of FasL at 24 h, with an increased intensity at 48 h, but not in AdV-5 infected or uninfected islets. TUNEL labeling of pancreatic islet allografts at 24, 48 h revealed apoptosis that was not in AdV-5 infected allografts. CONCLUSIONS: Though co-transplantation of FasL-expressing testicular cells can induce privilege of islet allografts and prolong allograft survival, direct expression of FasL on islet allografts infected with AdV-FasL may accelerate islets rejection by islet apoptosis and granulocyte infiltration.

[Whole pancreatic transplantation and islet transplantation. Experiment notes]. / Trapianto di pancreas intero e trapianto di isole. Note sperimentali.

BACKGROUND: The results of pancreas transplantation have greatly improved in recent years. The path to further improvements goes through extensive experimental researches. METHODS: This study describes the effects of different procedures as hemodynamic asset and postoperative outcome. Twenty-nine swine underwent a total pancreatectomy, and were stratified into five groups. Group one (n = 5) served as control. Group two (n = 7) was autotransplanted. Group three (n = 6) and group four (n = 6) underwent allotransplantation; the first without immunosuppression and the second treated with cyclosporine and steroids. In group five (n = 5) Langerhans Islets transplantation was performed. RESULTS: Survival was different depending on which methodology was applied. The postoperative survival was 7 +/- 2 days in group one, 24 +/- 16 days in group two, 17 +/- 7 days in group three, 27 +/- 8 days in group four and 12 +/- 6 days in group five. CONCLUSIONS: The postoperative glucose control was normal in group two and group four while a severe diabetes appeared in group one (group 1 vs group 2: p < 0.05) and in group three during acute graft rejection after the 12th postoperative day (group 3 vs group 4: p < 0.05). Glycemia was slightly controlled in group five. The intraoperative hemodynamic status was evaluated at the time of pancreatectomy, harvesting, revascularization, and when surgery was over. Among the different parameters studied (mean arterial and pulmonary pressure, pulmonary wedge pressure, central venous pressure, cardiac output, oxygen extraction ratio, systemic vascular resistance, oxygen delivery and oxygen consumption), a statistically significant difference between group one and group five (p < 0.05) was observed.

[Effects of Fas ligand expression on pancreatic islet allografts].

OBJECTIVE: To investigate the immune privilege of islet allgrafts induced by the Fas ligand (FasL) expressed by co-transplanted testicular Sertoli cells and the effects of FasL gene transfected into islet cells on pancreatic islet allografts. METHODS: The allogeneic islets and testicular cells from rats were co-transplanted into diabetic recipients. Pancreatic islet cells were firstly infected with the recombinant adenovirus AdV-FasL and then transplanted into the diabetic recipients. Allograft survival, islet function and apoptosis of infiltrative lymphocytes in allografts and gene-transfected islet allografts were observed. RESULTS: All the animals receiving islet allografts alone returned to a diabetic status in several days (mean survival time = 6.3 +/- 0.56 days). When the number of testicular cells co-transplanted with islets increased to 1 x 10(7), all the animals remained normoglycemic throughout the follow-up period (P < 0.05). Sertoli cells expressing FasL induced apoptosis of infiltrative lymphocytes in the allografts. In the group of FasL gene transfection, the rejection of allografts was accelerated and the allograft survival time shortened to 3.4 +/- 0.24 days (P < 0.05). Pancreatic islets infected with AdV-FasL demonstrated positive staining for FasL at the 24th hour and increased intensity at the 48th hour after transplantation. After the transplantation, apoptosis of FasL-transfected islet cells occurred. CONCLUSIONS: Co-transplantation of testicular Sertoli cells expressing FasL and islets can induce apoptosis of activated lymphocytes and allows long-term survival of allogeneic islets because of immune privilege. However, direct expression of FasL by islet allografts infected with AdV-FasL accelerates the islet rejection by islet cell apoptosis and granulocytic infiltration.