John P. Leone

Excellence of the two-layer method (University of Wisconsin solution/perfluorochemical) in pancreas preservation before islet isolation☆

BACKGROUND In islet transplantation pancreatic preservation before islet isolation is an obstacle compromising islet yield and viability. We tested the feasibility of a two-layer method (University of Wisconsin solution [UW]/perfluorochemical) for pancreatic preservation before islet isolation. METHODS Dog pancreases were processed into pure islets by the method of Ricordi preceded by five different preservations (groups 1-a and 1-b, the two-layer method for 3 and 24 hours; groups 2-a and 2-b, simple cold storage in UW for 3 and 24 hours; group 3, without preservation). Islet yields and functional success after autotransplantation into the liver were compared among the groups. RESULTS Postpurification islet equivalents (IE)/gm pancreas and functional success rate were 5600 (mean), 83% in group 1-a; 4000, 56% in group 1-b; 4700, 33% in group 2-a; 1300, 0% in group 2-b; and 5000, 89% in group 3 (p < 0.05; 2b versus 1-a, 1-b, and 3), respectively. There was no statistical difference among groups 1-a, 1-b, and 3 in terms of islet yield and function (p > 0.2). CONCLUSIONS The two-layer method is more effective than conventional simple cold storage in UW for pancreatic preservation before islet isolation. Clinical trials with the two-layer method are warranted.

Nonalcoholic fatty liver disease epidemic and its implications for liver transplantation.

Nonalcoholic steatohepatitis (NASH) is increasingly recognized as the most common chronic liver disease worldwide. The aim of this study is to investigate the transplantation trends of liver transplant (LT) recipients with NASH. Using the United Network for Organ Sharing database, we found a steady increase in LT rate especially in those more than 65 years old. We identified differences across ethnic groups and United Network for Organ Sharing regions. This study highlights the impact of the rising prevalence of NASH on the demand for LT and provides invaluable information to healthcare policymakers and the transplant community about the target groups and geographic location for focused and early intervention.

Fatal disseminated intravascular coagulation after autologous islet transplantation

Autologous islet transplantation after pancreatectomy has been used in the surgical management of patients with intractable pain secondary to chronic pancreatitis. Total or near total pancreatectomy invariably leads to exogenous insulin dependence in these patients unless they undergo islet transplantation. Transplantation of autologous islet cells harvested from the patients pancreas into the liver through portal vein infusion has led to long-term euglycemia in 30% to 50% of patients. We report the development of disseminated intravascular coagulation and fatal hemorrhagic shock in a 36-year-old woman after total pancreatectomy and autologous islet transplantation through retrograde infusion into the splenic vein. We report the clinical and pathological findings and discuss the possible pathophysiological mechanisms involved in the development of disseminated intravascular coagulation after this procedure.

Obesity portends increased morbidity and earlier recurrence following liver transplantation for hepatocellular carcinoma

BACKGROUND Obesity has been associated with poor oncologic outcomes following pancreatoduodenectomy for pancreatic cancer. However, there is a paucity of evidence on the impact of obesity on postoperative complications, oncologic outcome and survival in patients with hepatocellular carcinoma (HCC) undergoing orthotopic liver transplantation (OLT). METHODS From a database of over 1000 patients who underwent OLT during 1996-2008, 159 patients with a diagnosis of HCC were identified. Demographic data, body mass index (BMI), perioperative parameters, recurrence and survival were obtained. Complications were grouped according to Clavien-Dindo grading (Grades I-V). RESULTS There were increased incidences of life-threatening complications in overweight (58%) and obese (70%) patients compared with the non-obese patient group (41%) (P < 0.05). Furthermore, the incidence of recurrence of HCC was doubled in the presence of overweight (15%) and obesity (15%) compared with non-obesity (7%) (P < 0.05). Time to recurrence also decreased significantly. Differences in mean ± standard deviation survival in the overweight (45 ± 3 months) and obese (41 ± 4 months) groups compared with the non-obese group (58 ± 6 months) did not reach statistical significance. CONCLUSIONS These findings indicate that BMI is an important surrogate marker for obesity and portends an increased risk for complications and a poorer oncologic outcome following OLT for HCC.

Transcontinental Shipping of Pancreatic Islets for Autotransplantation After Total Pancreatectomy

Islet autotransplantation prevents diabetes in some patients after total pancreatectomy. Pancreatectomy is done at most hospitals but islets are prepared at only a few centers. We report a case in which the pancreas was sent to a laboratory half a continent distant from the operative site, and islets were prepared and returned to the original hospital for autotransplantation 16 h after resection. At 10 months posttransplantation, the patient is normoglycemic and insulin independent, with an appropriate insulin secretion in response to glucose. Endocrine function can be retained after pancreatectomy even if the islets are isolated at a remote laboratory, and autotransplantation could be offered to patients without the need to travel. This outcome implies that the typical handling and processing of a pancreas destined to yield an islet allograft should not prevent the recovery of a sufficient number of viable β cells to establish insulin independence in type 1 diabetic recipients.

Effect of pancreatic warm ischemia on islet yield and viability in dogs

BACKGROUND Defining tolerable warm ischemia (WI) is mandatory before nonheartbeating cadavers can be used to enlarge the donor pool. No studies to date have precisely evaluated the effect of pancreatic WI on islet yield and viability in a large animal model. METHODS We used mongrel dogs in our study at the University of Minnesota. Excised pancreases were left in situ for a designated period (0, 30, 45, and 60 min in groups 1 to 4, respectively) of WI. Then, they were digested by the automated collagenase digestion method of Ricordi, purified on Euro-Ficoll discontinuous gradients with the COBE cell processor, and autotransplanted into the liver via a mesenteric vein. We compared the four groups in terms of islet yield, expressed as islet equivalents (IE; diameter standardizing to 150 microm) per pancreas weight (IE/g pancreas), and viability, assessed by functional success (maintenance of normoglycemia for 2 weeks) after transplant. RESULTS Mean islet yield (+/- SD) and the functional success rate after transplant were as follows: 6200+/-1800 IE/g pancreas and 4 of 4 (100%) in group 1; 6300+/-4400 and 4 of 4 (100%) in group 2; 3800+/-2600 and 2 of 4 (50%) in group 3; and 1400+/-1300 and 0 of 4 (0%) in group 4 (P=0.01 vs. group 1). CONCLUSIONS With 30 min or less of WI, there are no deleterious effects on islet yield and viability. However, with periods of WI longer than 30 min, the loss in islet yield is severe, resulting in functional failure after autotransplantation. The limit of WI that is tolerable for islets is shorter than for a whole pancreas.

Cyclosporine challenge test revisited: Does it predict outcome after solitary pancreas transplantation?

Background: The selection of patients for solitary pancreas transplantation (PTA) requires identification of individuals who will not develop acute renal dysfunction in response to immunosuppressants. A cyclosporine challenge test (CCT) was developed to predict post‐PTA kidney dysfunction secondary to calcineurin inhibitor immunosuppressants. We now report on the long‐term follow‐up of patients who received a PTA after undergoing a CCT. 
Methods: Twelve potential PTA recipients were administered cyclosporine A (CsA) for 6 wk. Creatinine clearance (CrCl) was measured at 2, 4, and 6 wk. Those who did not fail the CCT received PTA. Baseline and post‐transplant CrCl were retrospectively evaluated in the original cohort and in a group of matched patients who received PTA without a CCT. 
Results: Of the original 12 recipients evaluated with the CCT, 6 received PTA. CrCl was followed for a mean of 45.8 months. Of the 4 who remained alive, 2 went on to develop renal failure (CrCl<30 mL/min) at 18 and 65 months post‐transplant. The baseline CrCl was higher in PTA recipients who had not been selected to be studied with CCT than those that were (117±32 vs 78±13 mL/min). By 12 months post‐PTA, the CrCl was no longer different between the groups selected to be screened with CCT and those that were not. 
Conclusions: CCT may help predict risk for short‐term changes in renal function (<18 months) in response to CsA. CCT may be most helpful in candidates for PTA with borderline renal insufficiency (60–80 mL/min).

Posttransplant nonfunction of canine islets in PVG rats deficient in complement component C6

BACKGROUND Discordant islet xenografts are immediately nonfunctional in nonimmunosuppressed recipients other than the mouse, a process called primary nonfunction. Although at present it is unknown whether complement is involved, complement might participate in the induction of primary nonfunction through a number of mechanisms. We investigated the potential role of the membrane attack complex of complement in primary nonfunction of transplanted xenoislets. METHODS Canine islets were transplanted into both nonimmunosuppressed and immunosuppressed normocomplementemic and C6-deficient (C6D) PVG rats. Cyclosporine, rapamycin, deoxyspergualin, and mycophenolate mofetil were used for immunosuppression from day -3 to cessation of islet cell function. Serum glucose was measured at 6 hr after transplant and daily thereafter. Xenograft tissue sections were obtained at various times after transplant and stained for inflammatory cells and insulin. RESULTS Canine islets grafted in nonimmunosuppressed C6D rats and normocomplementemic rats underwent primary nonfunction in all animals. The incidence of primary nonfunction in animals receiving a four-drug immunosuppressive regimen was 33% in the normocomplementemic rats but only 10% in the C6D rats. The mean functional islet survival time was 1.57+/-0.33 days in the normocomplementemic group and 2.70+/-0.67 days in the C6D group (P=0.38). The islet xenografts showed little difference in degree and composition of cell infiltration between normocomplementemic and C6D rats. CONCLUSION The membrane attack complex does not appear to play a major role in primary nonfunction of canine islet xenografts in nonimmunosuppressed PVG rats. However, there was a lower incidence of primary nonfunction and a longer posttransplant survival time in immunosuppressed C6D rats, suggesting the membrane attack complex may play a minor role in recipients that are heavily immunosuppressed.

Immediate Insulin-Independence After Retransplantation of Islets Prepared From an Allograft Pancreatectomy in a Type 1 Diabetic Patient

TRANSPLANTATION of human islet allografts into insulin dependent diabetes mellitus (IDDM) patients has proved to be challenging. Transplanted islets in such recipients have delayed graft function before insulin independence is achieved, and only 10% remain functioning at 1 year. We describe a successful islet transplant in a IDDM patient who required a transplant pancreatectomy secondary to chronic graft pancreatitis.

Total lymphoid irradiation, without intrathymic injection of donor cells, induces indefinite acceptance of heart but not islet or skin allografts in rats

Abstract  Allograft tolerance oc curs in rodents given a dose of anti‐lymphocyte serum (ALS) and intra thymic injection (ITI) of donor splenocytes (SC) 1–3 weeks prior to transplant (TX). The purpose of our study was to test total lymphoid irradiation (TLI) as an alternative to ALS in ITI tolerance induction to heart, islet, and skin allografts. Pre‐pubertal Wistar Furth rats were recipients. ITI of donor (Lewis) SC was done at the end of the TLI course. Rats received either a het‐erotopic heart, a skin graft, or 2300 islets (diabetic recipients) intraportally from Lewis donors. TLI (with out ITI) in a dose of 200 rads/day for 5 consecutive days, followed by TX in 3 weeks resulted in indefinite ac ceptance of heart (but not islet or skin) grafts in 60 % of the recipients. These data indicate that TLI by a dose schedule of 200 rads/day for 5 days should be tested for clinical relevance in large animal recipients of immediately vascularized grafts.