Progress in individualizing autologous islet isolation techniques for pediatric islet autotransplantation after total pancreatectomy in children for chronic pancreatitis

Total pancreatectomy with islet autotransplantation is performed to treat chronic pancreatitis in children. Successful islet isolation must address the challenges of severe pancreatic fibrosis and young donor age. We have progressively introduced modifications to optimize enzymatic and mechanical dissociation of the pancreas during islet isolation. We evaluated 2 islet isolation metrics in 138 children-digest islet equivalents per gram pancreas tissue (IEQ/g) and digest IEQ per kilogram body weight (IEQ/kg), using multiple regression to adjust for key disease and patient features. Islet yield at digest had an average 4569 (standard deviation 2949) islet equivalent (IEQ)/g and 4946 (4009) IEQ/kg, with 59.1% embedded in exocrine tissue. Cases with very low yield (<2000 IEQ/g or IEQ/kg) have decreased substantially over time, 6.8% and 9.1%, respectively, in the most recent tertile of time compared to 19.2% and 23.4% in the middle and 34.1% and 36.4% in the oldest tertile. IEQ/g and IEQ/kg adjusted for patient and disease factors improved in consistency and yield in the modern era. Minimal mechanical disruption during digestion, warm enzymatic digestion using enzyme collagenase:NP activity ratio < 10:1, coupled with extended distension and trimming time during islet isolation of younger and fibrotic pediatric pancreases, gave increased islet yield with improved patient outcomes.

Total Pancreatectomy With Intraportal Islet Autotransplantation as a Treatment of Chronic Pancreatitis in Patients With CFTR Mutations

OBJECTIVES

Chronic pancreatitis (CP) is an infrequent but debilitating complication associated with CFTR mutations. Total pancreatectomy with islet autotransplantation (TPIAT) is a treatment option for CP that provides pain relief and preserves β-cell mass, thereby minimizing the complication of diabetes mellitus. We compared outcomes after TPIAT for CP associated with CFTR mutations to CP without CTFR mutations.

METHODS

All TPIATs performed between 2002 and 2014 were retrospectively reviewed: identifying 20 CFTR homozygotes (cystic fibrosis [CF] patients), 19 CFTR heterozygotes, and 20 age-/sex-matched controls without CFTR mutations. Analysis of variance and χ tests were used to compare groups.

RESULTS

Baseline demographics were not different between groups. Postoperative glycosylated hemoglobin and C-peptide levels were similar between groups, as were islet yield and rate of postoperative complications. At 1 year, 40% of CF patients, 22% of CFTR heterozygotes, and 35% of control patients were insulin independent.

CONCLUSION

Total pancreatectomy with islet autotransplantation is a safe, effective treatment option for CF patients with CP, giving similar outcomes for those with other CP etiologies.

Significant arterial complications after pancreas transplantation-A single-center experience and review of literature

Arterial fistulas and pseudoaneurysms are rarely described significant arterial complications associated with pancreas transplantation that sometimes present with herald or catastrophic bleeding. We herein describe our institutional case series with a focus on management and outcomes. Of 2256 pancreas transplants, 24 arterial complications were identified in 23 recipients. Chart review was performed to describe the clinical characteristics, treatments, and outcomes of the complications (pseudoaneurysm, arterial enteric/cystic/ureteric fistula, or arteriovenous fistula). Of these 23 patients, 57% had a failed allograft at the time of the complication. Nine patients underwent primary surgical repair of 10 complications, 13 were treated by endovascular methods, and one patient by medical management. In total, 3 embolized patients rebled, 2 of which had failed allografts prior to treatment. Of those with graft function that were treated by embolization alone, all retained graft function. Diagnosis of arterial complications requires a high degree of suspicion and should involve early systemic angiography to evaluate the pancreatic vasculature. Management can be endovascular or surgical and should be individualized. We report our center's evolution from a predominantly surgical to endovascular approach as a definitive vs stabilizing therapy, with selective coiling mostly reserved for well-defined peripheral lesions in patients with a functioning allograft.

Optimizing outcomes in pancreas transplantation: Impact of organ preservation time

Recent changes to pancreas graft allocation policy have increased the number of organs available for regional and distant sharing, which results in a corresponding increase in preservation time. We sought to systematically assess the impact of cold ischemia time (CIT) on outcomes post-transplant. A retrospective review of 1253 pancreas transplants performed at a single transplant center was performed to correlate CIT to transplant outcomes. The rate of technical failure (TF) increased with 20+ hours of CIT, with a 2.7-fold to 6.2-fold increased rate of TF for pancreas after kidney (PAK), simultaneous pancreas and kidney (SPK), and pancreas transplants overall. Long-term graft survival was best with <12 hours of CIT; graft failure increased 1.2-fold to 1.4-fold with 12-24 hours of CIT and 2.2-fold with 24+ hours. CIT had less influence on the pancreas transplant alone category than either SPK or PAK and had markedly more influence on grafts from older (age >25 years) and overweight (body mass index >25) donors. In the final analysis, grafts with <12 hours of CIT performed the best overall, and strategies that reduce CIT (such as early allocation, pre-recovery cross-matching, and chartered flights for organs) should be considered whenever possible.

Comparison of Tolerated and Rejected Islet Grafts: A Gene Expression Study

Recently we showed that donor-specific tolerance to MHC-matched islet allografts in diabetic NOD mice could be induced by simultaneous islet and bone marrow transplantation. Mononuclear cell infiltration surrounding the islets was also found in tolerated grafts. In this study, we compared gene expression in the tolerated and rejected islet grafts by using Affymetrix Murine U74A oligonucleotide arrays. To confirm the results of microarray analysis, we performed real-time PCR and RNase protection assay on selected genes. Of over 12,000 genes studied, 57 genes were expressed at consistently higher levels in tolerated islet grafts, and 524 genes in rejected islet grafts. Genes from a variety of functional clusters were found to be different between rejected and tolerated grafts. In the rejected islet grafts, a number of T-cell surface markers and of cytotoxicity-related genes were highly expressed. Also in the rejected grafts, a number of cytokines and chemokines and their receptors were highly expressed. The differential expression of selected genes found by microarray analysis was also confirmed by real-time PCR and RNase protection assay. Our results indicated that gene microarray analysis can help us to detect gene expression differences representative of the biologic mechanisms of tolerance and rejection.

Long-Term Glycemic Control in Adult Patients Undergoing Remote vs. Local Total Pancreatectomy With Islet Autotransplantation

OBJECTIVES

Total pancreatectomy with islet autotransplantation (TPIAT) is increasingly performed with remote islet cell processing and preparation, i.e., with islet cell isolation performed remotely from the primary surgical site at an appropriately equipped islet isolation facility. We aimed to determine whether TPIAT using remote islet isolation results in comparable long-term glycemic outcomes compared with TPIAT performed with standard local isolation.

METHODS

We performed a retrospective cohort study of adult patients who underwent TPIAT at three tertiary care centers from 2010 to 2013. Two centers performed remote isolation and one performed local isolation. Explanted pancreata in the remote cohort were transported ∼130 miles to and from islet isolation facilities. The primary outcome was insulin independence 1 year following transplant.

RESULTS

Baseline characteristics were similar between groups except the remote cohort had higher preoperative hemoglobin A1c (HbA1c; 5.43 vs. 5.25, P=0.02) and there were more females in the local cohort (58% vs. 76%, P=0.049). At 1 year, 27% of remote and 32% of local patients were insulin independent (P=0.48). Remote patients experienced a greater drop in fasting c-peptide (-1.66 vs. -0.64, P=0.006) and a greater rise in HbA1c (1.65 vs. 0.99, P=0.014) at 1-year follow-up. A preoperative c-peptide >2.7 (odds ratio (OR) 4.4, 95% confidence interval (CI) 1.6-14.3) and >3,000 islet equivalents/kg (OR 11.0, 95% CI 3.2-37.3) were associated with one-year insulin independence in the local group.

CONCLUSIONS

At 1 year after TPIAT, patients undergoing remote surgery have equivalent rates of long-term insulin independence compared with patients undergoing TPIAT locally, but metabolic control is superior with local isolation.

Sitagliptin Treatment After Total Pancreatectomy With Islet Autotransplantation: A Randomized, Placebo-Controlled Study

Insulin independence after total pancreatectomy and islet autotransplant (TPIAT) for chronic pancreatitis is limited by a high rate of postprocedure beta cell apoptosis. Endogenous glucagon-like peptide-1 and glucose-dependent insulinotropic peptide, which are increased by dipeptidyl peptidase 4 inhibitor therapy (sitagliptin) may protect against beta cell apoptosis. To determine the effect of sitagliptin after TPIAT, 83 adult TPIAT recipients were randomized to receive sitagliptin (n = 54) or placebo (n = 29) for 12 months after TPIAT. At 12 and 18 months after TPIAT, participants were assessed for insulin independence; metabolic testing was performed with mixed meal tolerance testing and frequent sample intravenous glucose tolerance testing. Insulin independence did not differ between the sitagliptin and placebo groups at 12 months (42% vs. 45%, p = 0.82) or 18 months (36% vs. 44%, p = 0.48). At 12 months, insulin dose was 9.0 (standard error 1.7) units/day and 7.9 (2.2) units/day in the sitagliptin and placebo groups, respectively (p = 0.67) and at 18 months 10.3 (1.9) and 7.1 (2.6) units/day, respectively (p = 0.32). Hemoglobin A_1c levels and insulin secretory measures were similar in the two groups, as were adverse events. In conclusion, sitagliptin could be safely administered but did not improve metabolic outcomes after TPIAT.

Total Pancreatectomy With Islet Autotransplantation Improves Quality of Life in Patients With Refractory Recurrent Acute Pancreatitis

BACKGROUND & AIMS

Therapeutic options are limited for patients with recurrent acute pancreatitis who have intractable symptoms despite maximal endoscopic and medical treatment, but equivocal or no morphologic or functional evidence of chronic pancreatitis. We performed a prospective observational cohort study to determine the efficacy of total pancreatectomy with islet autotransplantation (TPIAT) for these patients.

METHODS

We collected data from all patients undergoing TPIAT at the University of Minnesota from 2007 through 2013; 49 patients (42 female; mean age, 32.8 ± 7.8 years) had a diagnosis of recurrent acute pancreatitis not provoked by intervention, with negative or equivocal findings from nondiagnostic imaging or pancreatic function tests for chronic pancreatitis, and intractable pain between episodes. Data on insulin use, narcotic requirements, pain scores, and health-related quality of life were collected before TPIAT; 3 months, 6 months, and 1 year afterward; and then yearly.

RESULTS

All 49 patients studied required narcotics before TPIAT (45 daily users and 4 intermittent users); 2 had insulin-treated diabetes. At 1 year after TPIAT, 22 out of 48 patients (46%) reported no use of narcotic pain medications (P < .001 vs baseline). Health-related quality of life score, measured by the physical and mental component summary score, increased by approximately 1 standard deviation from the population mean (P < .001 for the physical component summary; P = .019 for the mental component summary). At 1 year after TPIAT, 21 out of 48 patients (45%) were insulin independent; their mean percent glycosylated hemoglobin A1c at 1 year after TPIAT was 6.0% ± 0.9% (5.2% ± 0.6% pre-TPIAT).

CONCLUSIONS

Patients with recurrent acute pancreatitis but lacking clear chronic pancreatitis benefit from TPIAT, with outcomes similar to those previously described for patients with chronic pancreatitis (improved quality of life and reduced narcotic use). For these patients who have otherwise limited surgical treatment options, TPIAT can be considered when medical and endoscopic therapies have failed.

HLA-A, -B, -C, -DR, and -DQ Matching in Pancreas Transplantation: Effect on Graft Rejection and Survival

To enhance selection of appropriate deceased donors for pancreas transplants, we sought to determine whether HLA matching improved posttransplantation outcomes. In this single-center study of 1219 pancreas transplants, we correlated posttransplantation outcomes with HLA-A, -B, -C, -DR, and -DQ matches and mismatches. Rejection was linearly correlated with the number of mismatches. The individual number of HLA mismatches reached significance at four or more with a 2.3- to 2.9-fold increase in rejection. The effect was most predominant with HLA-B (1.8-fold with one mismatch and 2.0-fold with two mismatches) and -DR (1.9-fold with two mismatches) loci, whereas HLA-A, -C, and -DQ matches or mismatches did not independently predict acute rejection. The affect was strongest in solitary pancreas transplants, with little impact for simultaneous pancreas and kidney (SPK). In contrast, HLA matching did not affect graft or patient survival rates but was associated with a reduced risk of opportunistic infection. Avoidance of acute rejection saved an estimated $32 000 for solitary pancreas recipients and $52 000 for SPK recipients in hospital costs. Our data do not support the use of HLA matching for predicting pancreas graft survival but do support its significance for the reduction of acute rejection, particularly for solitary pancreas recipients.

Microbial contamination of transplant solutions during pancreatic islet autotransplants is not associated with clinical infection in a pediatric population

BACKGROUND/OBJECTIVES

Total pancreatectomy and islet autotransplant (TP-IAT) is a potential treatment for children with severe refractory chronic pancreatitis. Cultures from the resected pancreas and final islet preparation are frequently positive for microbes. It is unknown whether positive cultures are associated with adverse outcomes in pediatric patients.

METHODS

We reviewed the medical records of children (n = 86) who underwent TP-IAT from May 2006-March 2015 with emphasis on demographics, previous pancreatic interventions, culture results, islet yield, hospital days, posttransplant islet function, and posttransplant infections. We compared outcomes in patients with positive (n = 57) and negative (n = 29) cultures.

RESULTS

Patients with positive cultures had higher rates of previous pancreas surgery (P = 0.007) and endoscopic retrograde cholangiopancreatography (P < 0.0001). Positive cultures were not associated with posttransplant infections (P = 1.00) or prolonged hospital length of stay (P = 0.29). Patients with positive final islet preparation culture showed increased rates of graft failure at 2 years posttransplant (P = 0.041), but not when adjusted for islet mass transplanted (P = 0.39).

CONCLUSIONS

Positive cultures during pediatric TP-IATs do not increase the risk of posttransplant infections or prolong hospital length of stay. Endocrine function depends on islet mass transplanted.

Pediatric Autologous Islet Transplantation

A total pancreatectomy and islet autotransplant (TPIAT) offers substantial pain relief and improved quality of life for children who are severely affected by chronic or recurrent acute pancreatitis and for whom the usual medical and endoscopic therapies have failed. The pancreas is entirely resected, and the pancreatic islets are isolated from the pancreas and infused back into the patient's liver. Because this is an autologous transplant, no immunosuppression is required. Over several months, the islets engraft in the liver; the patient is then slowly weaned off insulin therapy. Slightly more than 40 % of patients become and remain insulin independent, yet even among patients who remain on insulin, most have some islet function, permitting easier diabetes control. The majority of patients experience pain relief, with significant improvements in health-related quality of life. A TPIAT should be considered for children who are significantly disabled by chronic pancreatitis.

Islet Oxygen Consumption Rate (OCR) Dose Predicts Insulin Independence in Clinical Islet Autotransplantation

Background

Reliable in vitro islet quality assessment assays that can be performed routinely, prospectively, and are able to predict clinical transplant outcomes are needed. In this paper we present data on the utility of an assay based on cellular oxygen consumption rate (OCR) in predicting clinical islet autotransplant (IAT) insulin independence (II). IAT is an attractive model for evaluating characterization assays regarding their utility in predicting II due to an absence of confounding factors such as immune rejection and immunosuppressant toxicity.

Methods

Membrane integrity staining (FDA/PI), OCR normalized to DNA (OCR/DNA), islet equivalent (IE) and OCR (viable IE) normalized to recipient body weight (IE dose and OCR dose), and OCR/DNA normalized to islet size index (ISI) were used to characterize autoislet preparations (n = 35). Correlation between pre-IAT islet product characteristics and II was determined using receiver operating characteristic analysis.

Results

Preparations that resulted in II had significantly higher OCR dose and IE dose (p<0.001). These islet characterization methods were highly correlated with II at 6–12 months post-IAT (area-under-the-curve (AUC) = 0.94 for IE dose and 0.96 for OCR dose). FDA/PI (AUC = 0.49) and OCR/DNA (AUC = 0.58) did not correlate with II. OCR/DNA/ISI may have some utility in predicting outcome (AUC = 0.72).

Conclusions

Commonly used assays to determine whether a clinical islet preparation is of high quality prior to transplantation are greatly lacking in sensitivity and specificity. While IE dose is highly predictive, it does not take into account islet cell quality. OCR dose, which takes into consideration both islet cell quality and quantity, may enable a more accurate and prospective evaluation of clinical islet preparations.

Three types of simultaneous pancreas and kidney transplantation

PURPOSE

The purposes of this study were to study and compare clinical and functional outcomes after simultaneous deceased donor pancreas and kidney transplantation (SPK DD), simultaneous deceased donor pancreas and living donor kidney transplantation (SPK DL), and simultaneous living donor pancreas and kidney transplantation (SPK LL).

METHODS

From January 1, 1996 to September 1, 2005, 8918 primary, simultaneous pancreas and kidney transplantation (SPK) procedures were reported to the International Pancreas Transplant Registry. Of these, 8764 (98.3%) were SPK DD, 115 (1.3%) were SPK DL, and 39 (0.4%) were SPK LL. We compared these 3 groups with regard to several endpoints including patient and pancreas and kidney graft survival rates.

RESULTS

The 1-year and 3-year patient survival rates for SPK DD were 95% and 90%, 97% and 95% for SPK DL, and 100% and 100% for SPK LL recipients, respectively (P ≥ .07). The 1-year and 3-year pancreas graft survival rates for SPK DD were 84% and 77%, 83% and 71% for SPK DL, and 90% and 84% for SPK LL recipients, respectively (P ≥ .16). The 1-year and 3-year kidney graft survival rates for SPK DD were 92% and 84%, 94% and 86% for SPK DL, and 100% and 89% for SPK LL recipients, respectively (P ≥ .37).

CONCLUSIONS

Patient survival rates and graft survival rates for pancreas and kidney were similar among the 3 groups evaluated in this study.

Positive sterility cultures of transplant solutions during pancreatic islet autotransplantation are associated infrequently with clinical infection

BACKGROUND

Chronic pancreatitis is a painful and often debilitating disease. Total pancreatectomy with intra-portal islet autotransplantation (TP-IAT) is a treatment option that allows for pain relief and preservation of beta-cell mass, thereby minimizing the complication of diabetes mellitus. Cultures of harvested islets are often positive for bacteria, possibly due to frequent procedures prior to TP-IAT, such as endoscopic retrograde cholangiopancreatography (ERCP), stenting, or other operative drainage procedures. It is unclear if these positive cultures contribute to post-operative infections.

HYPOTHESIS

We hypothesized that positive cultures of transplant solutions will not be associated with increased infection risk.

METHODS

We reviewed retrospectively the sterility cultures from both the pancreas preservation solution used to transport the pancreas and the final islet preparation for intra-portal infusion of patients who underwent TP-IAT between April 2006 and November 2012. Two hundred fifty-one patients underwent total, near-total, or completion pancreatectomy with IAT and had complete sterility cultures. All patients received prophylactic peri-operative antibiotics. Patients with positive pancreas preservation solution or islet sterility cultures received further antibiotics for 5-7 d. Patients' medical records were reviewed for post-operative infections and causative organisms.

RESULTS

Of the 251 patients included, 151 (61%) had one or more positive bacterial cultures from the pancreas preservation solution or final islet product. Seventy-three of the 251 patients (29%) had an infectious complication. Thirty-four of the 73 (22%) patients with a post-operative infectious complication also had positive cultures. Only seven of 151 patients with positive cultures (4.7%) had an infectious complication caused by the same organism as that isolated from their pancreas or islet cell preparation.

CONCLUSIONS

In autologous islet preparations, isolation solutions frequently have positive cultures, but this finding is associated infrequently with clinical infection.

Assessment of β-cell mass and α- and β-cell survival and function by arginine stimulation in human autologous islet recipients

We used intravenous arginine with measurements of insulin, C-peptide, and glucagon to examine β-cell and α-cell survival and function in a group of 10 chronic pancreatitis recipients 1-8 years after total pancreatectomy and autoislet transplantation. Insulin and C-peptide responses correlated robustly with the number of islets transplanted (correlation coefficients range 0.81-0.91; P < 0.01-0.001). Since a wide range of islets were transplanted, we normalized the insulin and C-peptide responses to the number of islets transplanted in each recipient for comparison with responses in normal subjects. No significant differences were observed in terms of magnitude and timing of hormone release in the two groups. Three recipients had a portion of the autoislets placed within their peritoneal cavities, which appeared to be functioning normally up to 7 years posttransplant. Glucagon responses to arginine were normally timed and normally suppressed by intravenous glucose infusion. These findings indicate that arginine stimulation testing may be a means of assessing the numbers of native islets available in autologous islet transplant candidates and is a means of following posttransplant α- and β-cell function and survival.

Magnetic resonance imaging: a tool to monitor and optimize enzyme distribution during porcine pancreas distention for islet isolation

Porcine islet xenotransplantation is emerging as a potential alternative for allogeneic clinical islet transplantation. Optimization of porcine islet isolation in terms of yield and quality is critical for the success and cost-effectiveness of this approach. Incomplete pancreas distention and inhomogeneous enzyme distribution have been identified as key factors for limiting viable islet yield per porcine pancreas. The aim of this study was to explore the utility of magnetic resonance imaging (MRI) as a tool to investigate the homogeneity of enzyme delivery in porcine pancreata. Traditional and novel methods for enzyme delivery aimed at optimizing enzyme distribution were examined. Pancreata were procured from Landrace pigs via en bloc viscerectomy. The main pancreatic duct was then cannulated with an 18-g winged catheter and MRI performed at 1.5-T. Images were collected before and after ductal infusion of chilled MRI contrast agent (gadolinium) in physiological saline. Regions of the distal aspect of the splenic lobe and portions of the connecting lobe and bridge exhibited reduced delivery of solution when traditional methods of distention were utilized. Use of alternative methods of delivery (such as selective re-cannulation and distention of identified problem regions) resolved these issues, and MRI was successfully utilized as a guide and assessment tool for improved delivery. Current methods of porcine pancreas distention do not consistently deliver enzyme uniformly or adequately to all regions of the pancreas. Novel methods of enzyme delivery should be investigated and implemented for improved enzyme distribution. MRI serves as a valuable tool to visualize and evaluate the efficacy of current and prospective methods of pancreas distention and enzyme delivery.

Temperature profiles of different cooling methods in porcine pancreas procurement

Porcine islet xenotransplantation is a promising alternative to human islet allotransplantation. Porcine pancreas cooling needs to be optimized to reduce the warm ischemia time (WIT) following donation after cardiac death, which is associated with poorer islet isolation outcomes. This study examines the effect of four different cooling Methods on core porcine pancreas temperature (n = 24) and histopathology (n = 16). All Methods involved surface cooling with crushed ice and chilled irrigation. Method A, which is the standard for porcine pancreas procurement, used only surface cooling. Method B involved an intravascular flush with cold solution through the pancreas arterial system. Method C involved an intraductal infusion with cold solution through the major pancreatic duct, and Method D combined all three cooling Methods. Surface cooling alone (Method A) gradually decreased core pancreas temperature to <10 °C after 30 min. Using an intravascular flush (Method B) improved cooling during the entire duration of procurement, but incorporating an intraductal infusion (Method C) rapidly reduced core temperature 15-20 °C within the first 2 min of cooling. Combining all methods (Method D) was the most effective at rapidly reducing temperature and providing sustained cooling throughout the duration of procurement, although the recorded WIT was not different between Methods (P = 0.36). Histological scores were different between the cooling Methods (P = 0.02) and the worst with Method A. There were differences in histological scores between Methods A and C (P = 0.02) and Methods A and D (P = 0.02), but not between Methods C and D (P = 0.95), which may highlight the importance of early cooling using an intraductal infusion. In conclusion, surface cooling alone cannot rapidly cool large (porcine or human) pancreata. Additional cooling with an intravascular flush and intraductal infusion results in improved core porcine pancreas temperature profiles during procurement and histopathology scores. These data may also have implications on human pancreas procurement as use of an intraductal infusion is not common practice.

Deterioration of glycemic control after corticosteroid administration in islet autotransplant recipients: a cautionary tale

Islet autotransplantation (IAT) is performed at the time of total pancreatectomy (TP) to prevent or minimize post-surgical diabetes. Corticosteroids induce insulin resistance and present a risk to islet autografts, through glucotoxicity and increased metabolic demand on a marginal islet mass. We present four IAT recipients treated with oral or injected corticosteroids after transplant for medical conditions unrelated to chronic pancreatitis or TPIAT. Hyperglycemia or insulin resistance was evident in all four patients, including reversion to long-term insulin therapy in two patients. One patient receiving corticosteroid injections had a transient increase in hemoglobin A1c (+0.6% above baseline), and one patient given a one time dose of oral dexamethasone exhibited hyperglycemia despite high insulin (>200 mU/L) and C-peptide (15.3 ng/mL) production on an oral glucose tolerance test. IAT recipients have insufficient islet mass to compensate for the insulin resistance induced by corticosteroids. Caution should be given to using these agents in IAT recipients. When corticosteroids are medically necessary, insulin therapy should be administered temporarily to compensate for the increased metabolic demand and minimize long-term risks on the islet graft.

Long-term outcomes of total pancreatectomy and islet auto transplantation for hereditary/genetic pancreatitis

BACKGROUND

Chronic pancreatitis is a debilitating disease resulting from many causes. The subset with hereditary/genetic pancreatitis (HGP) not only has chronic pain, but also an increased risk for pancreatic cancer. Long-term outcomes of total pancreatectomy (TP) and islet autogeneic transplantation (IAT) for chronic pancreatitis due to HGP are not clear.

STUDY DESIGN

We reviewed a prospectively maintained database of 484 TP-IATs from 1977 to 2012 at a single center. The outcomes (eg, pain relief, narcotic use, β-cell function, health-related quality of life measures) of patients who received TP-IAT for HGP (protease trypsin 1, n = 38; serine protease inhibitor Kazal type 1, n = 9; cystic fibrosis transmembrane conductance regulator, n = 14; and familial, n = 19) were evaluated and compared with those with non-hereditary/nongenetic causes.

RESULTS

All 80 patients with HGP were narcotic dependent and failed endoscopic management or direct pancreatic surgery. Post TP-IAT, 90% of the patients were pancreatitis pain free with sustained pain relief; >65% had partial or full β-cell function. Compared with nonhereditary causes, HGP patients were younger (22 years old vs 38 years old; p ≤ 0.001), had pancreatitis pain of longer duration (11.6 ± 1.1 years vs 9.0 ± 0.4 years; p = 0.016), had a higher pancreas fibrosis score (7 ± 0.2 vs 4.8 ± 0.1; p ≤ 0.001), and trended toward lower islet yield (3,435 ± 361 islet cell equivalent vs 3,850 ± 128 islet cell equivalent; p = 0.28). Using multivariate logistic regression, patients with non-HGP causes (p = 0.019); lower severity of pancreas fibrosis (p < 0.001); shorter duration of years with pancreatitis (p = 0.008); and higher transplant islet cell equivalent per kilogram body weight (p ≤ 0.001) were more likely to achieve insulin independence (p < 0.001). There was a significant improvement in health-related quality of life from baseline by RAND 36-Item Short Form Health Survey and in physical and mental component health-related quality of life scores (p < 0.001). None of the patients in the entire cohort had cancer of pancreatic origin in the liver or elsewhere develop during 2,936 person-years of follow-up.

CONCLUSIONS

Total pancreatectomy and IAT in patients with chronic pancreatitis due to HGP cause provide long-term pain relief (90%) and preservation of β-cell function. Patients with chronic painful pancreatitis due to HGP with a high lifetime risk of pancreatic cancer should be considered earlier for TP-IAT before pancreatic inflammation results in a higher degree of pancreatic fibrosis and islet cell function loss.

Long-term outcomes of total pancreatectomy and islet auto transplantation for hereditary/genetic pancreatitis

BACKGROUND

Chronic pancreatitis is a debilitating disease resulting from many causes. The subset with hereditary/genetic pancreatitis (HGP) not only has chronic pain, but also an increased risk for pancreatic cancer. Long-term outcomes of total pancreatectomy (TP) and islet autogeneic transplantation (IAT) for chronic pancreatitis due to HGP are not clear.

STUDY DESIGN

We reviewed a prospectively maintained database of 484 TP-IATs from 1977 to 2012 at a single center. The outcomes (eg, pain relief, narcotic use, β-cell function, health-related quality of life measures) of patients who received TP-IAT for HGP (protease trypsin 1, n = 38; serine protease inhibitor Kazal type 1, n = 9; cystic fibrosis transmembrane conductance regulator, n = 14; and familial, n = 19) were evaluated and compared with those with non-hereditary/nongenetic causes.

RESULTS

All 80 patients with HGP were narcotic dependent and failed endoscopic management or direct pancreatic surgery. Post TP-IAT, 90% of the patients were pancreatitis pain free with sustained pain relief; >65% had partial or full β-cell function. Compared with nonhereditary causes, HGP patients were younger (22 years old vs 38 years old; p ≤ 0.001), had pancreatitis pain of longer duration (11.6 ± 1.1 years vs 9.0 ± 0.4 years; p = 0.016), had a higher pancreas fibrosis score (7 ± 0.2 vs 4.8 ± 0.1; p ≤ 0.001), and trended toward lower islet yield (3,435 ± 361 islet cell equivalent vs 3,850 ± 128 islet cell equivalent; p = 0.28). Using multivariate logistic regression, patients with non-HGP causes (p = 0.019); lower severity of pancreas fibrosis (p < 0.001); shorter duration of years with pancreatitis (p = 0.008); and higher transplant islet cell equivalent per kilogram body weight (p ≤ 0.001) were more likely to achieve insulin independence (p < 0.001). There was a significant improvement in health-related quality of life from baseline by RAND 36-Item Short Form Health Survey and in physical and mental component health-related quality of life scores (p < 0.001). None of the patients in the entire cohort had cancer of pancreatic origin in the liver or elsewhere develop during 2,936 person-years of follow-up.

CONCLUSIONS

Total pancreatectomy and IAT in patients with chronic pancreatitis due to HGP cause provide long-term pain relief (90%) and preservation of β-cell function. Patients with chronic painful pancreatitis due to HGP with a high lifetime risk of pancreatic cancer should be considered earlier for TP-IAT before pancreatic inflammation results in a higher degree of pancreatic fibrosis and islet cell function loss.

Proposed thresholds for pancreatic tissue volume for safe intraportal islet autotransplantation after total pancreatectomy

The simple question of how much tissue volume (TV) is really safe to infuse in total pancreatectomy-islet autotransplantation (TP-IAT) for chronic pancreatitis (CP) precipitated this analysis. We examined a large cohort of CP patients (n = 233) to determine major risk factors for elevated portal pressure (PP) during islet infusion, using bivariate and multivariate regression modeling. Rates of bleeding requiring operative intervention and portal venous thrombosis (PVT) were evaluated. The total TV per kilogram body weight infused intraportally was the best independent predictor of change in PP (ΔPP) (p < 0.0001; R(2) = 0.566). Rates of bleeding and PVT were 7.73% and 3.43%, respectively. Both TV/kg and ΔPP are associated with increased complication rates, although ΔPP appears to be more directly relevant. Receiver operating characteristic analysis identified an increased risk of PVT above a suggested cut-point of 26 cmH2O (area under the curve = 0.759), which was also dependent on age. This ΔPP threshold was more likely to be exceeded in cases where the total TV was >0.25 cm(3)/kg. Based on this analysis, we have recommended targeting a TV of <0.25 cm(3)/kg during islet manufacturing and to halt intraportal infusion, at least temporarily, if the ΔPP exceeds 25 cmH2O. These models can be used to guide islet manufacturing and clinical decision making to minimize risks in TP-IAT recipients.

Comprehensive health assessment and five-yr follow-up of allogeneic islet transplant recipients

In patients with type 1 diabetes mellitus (T1DM) complicated by severe hypoglycemic episodes, fear of hypoglycemia can significantly impact daily life. We evaluated whether restoration of glycemic awareness and prevention of hypoglycemia by islet allotransplant could reduce fear and improve health status. We conducted a comprehensive evaluation of patient-based outcomes in 48 T1DM subjects screened for allogeneic islet transplant alone (ITA) and 27 subjects who received an ITA. A battery of generic health status and diabetes-specific measures were used to assess ITA at evaluation, six months, and then annually after ITA. Allogeneic islet transplant was associated with a reduction in behaviors adopted in avoiding hypoglycemia (p Value < 0.001) and attenuation in concerns about hypoglycemic episodes (p Value < 0.001). Changes in hypoglycemia fear tracked most closely with insulin use. While there was a trend toward global improvement in health as measured by the EQ-5D (p Value = 0.002) and in depression symptoms as measured by the Beck (p Value = 0.003), physical health remained unchanged following ITA. Our findings support the socioemotional benefits of ITA during the five years after ITA, which to some extent remains dependent on preservation of islet graft function.

A composite risk model for predicting technical failure in pancreas transplantation

Technical failure (TF) continues to have a significant impact on the success of pancreas transplantation. We assessed risk factors for TF in 1115 pancreas transplants performed at a single center between 1998 and 2011. The overall TF rate was 10.2%. In a multivariable model, donor BMI ≥ 30 (HR 1.87, p = 0.005), donor Cr ≥ 2.5 (HR 3.16, p = 0.007), donor age >50 (HR 1.73, p = 0.082) and preservation time >20 h (HR 2.17, p < 0.001) were associated with TF. Bladder drainage of exocrine secretions was protective (HR 0.54, p = 0.002). We incorporated these factors in a Composite Risk Model. In this model the presence of one risk factor did not significantly increase risk of TF (HR 1.35, p = 0.346). Two risk factors in combination increased risk greater than threefold (HR 3.65, p < 0.001) and three risk factors increased risk greater than sevenfold (HR 7.66, p = <0.001). The analysis also identified many factors that were not predictive of TF, including previous transplants, immunosuppressive agent selection, and almost all recipient demographic parameters. While the model suggests that two or more risk factors predict TF, strategies to reduce preservation time may mitigate some of this risk.

Persufflation (gaseous oxygen perfusion) as a method of heart preservation

Persufflation (PSF; gaseous oxygen perfusion) is an organ preservation technique with a potential for use in donor heart preservation. Improved heart preservation with PSF may improve outcomes by maintaining cardiac tissue quality in the setting of longer cold ischemia times and possibly increasing the number of donor hearts available for allotransplant. Published data suggests that PSF is able to extend the cold storage times for porcine hearts up to 14 hours without compromising viability and function, and has been shown to resuscitate porcine hearts following donation after cardiac death. This review summarizes key published work on heart PSF, including prospective implications and future directions for PSF in heart transplantation. We emphasize the potential impact of extending preservation times and expanding donor selection criteria in heart allotransplant. Additionally, the key issues that need to be addressed before PSF were to become a widely utilized preservation strategy prior to clinical heart transplantation are summarized and discussed.

Prospective randomized trial of maintenance immunosuppression with rapid discontinuation of prednisone in adult kidney transplantation

Rapid discontinuation of prednisone (RDP) has minimized steroid-related complications following kidney transplant (KT). This trial compares long-term (10-year) outcomes with three different maintenance immunosuppressive protocols following RDP in adult KT. Recipients (n=440; 73% living donor) from March 2001 to April 2006 were randomized into one of three arms: cyclosporine (CSA) and mycophenolate mofetil (MMF) (CSA/MMF, n=151); high-level tacrolimus (TAC, 8-12 μg/L) and low-level sirolimus (SIR, 3-7 μg/L) (TACH/SIRL, n=149) or low-level TAC (3-7 μg/L) and high-level SIR (8-12 μg/L) (TACL/SIR(H) , n=140). Median follow-up was ∼7 years. There were no differences between arms in 10-year actuarial patient, graft and death-censored graft survival or in allograft function. There were no differences in the 10-year actuarial rates of biopsy-proven acute rejection (30%, 26% and 20% in CSA/MMF, TACH/SIRL and TACL/SIRH) and chronic rejection (38%, 35% and 31% in CSA/MMF, TACH/SIRL and TACL/SIRH). Rates of new-onset diabetes mellitus were higher with TACH/SIRL (p=0.04), and rates of anemia were higher with TACH/SIRL and TACL/SIRH (p=0.04). No differences were found in the overall rates of 16 other post-KT complications. These data indicate that RDP-based protocol yield acceptable 10-year outcomes, but side effects differ based on the maintenance regimen used and should be considered when optimizing immunosuppression following RDP.

Supplements in human islet culture: human serum albumin is inferior to fetal bovine serum

Culture of human islets before clinical transplantation or distribution for research purposes is standard practice. At the time the Edmonton protocol was introduced, clinical islet manufacturing did not include culture, and human serum albumin (HSA), instead of fetal bovine serum (FBS), was used during other steps of the process to avoid the introduction of xenogeneic material. When culture was subsequently introduced, HSA was also used for medium supplementation instead of FBS, which was typically used for research islet culture. The use of HSA as culture supplement was not evaluated before this implementation. We performed a retrospective analysis of 103 high-purity islet preparations (76 research preparations, all with FBS culture supplementation, and 27 clinical preparations, all with HSA supplementation) for oxygen consumption rate per DNA content (OCR/DNA; a measure of viability) and diabetes reversal rate in diabetic nude mice (a measure of potency). After 2-day culture, research preparations exhibited an average OCR/DNA 51% higher (p < 0.001) and an average diabetes reversal rate 54% higher (p < 0.05) than clinical preparations, despite 87% of the research islet preparations having been derived from research-grade pancreata that are considered of lower quality. In a prospective paired study on islets from eight research preparations, OCR/DNA was, on average, 27% higher with FBS supplementation than that with HSA supplementation (p < 0.05). We conclude that the quality of clinical islet preparations can be improved when culture is performed in media supplemented with serum instead of albumin.

Pancreatectomy and autologous islet transplantation for painful chronic pancreatitis: indications and outcomes

Total pancreatectomy with intrahepatic autoislet transplantation (TP/IAT) is a definitive treatment for relentlessly painful chronic pancreatitis. Pain relief is reported to be achieved in approximately 80% of patients. Overall, 30% to 40% achieve insulin independence, and 70% of recipients remain insulin independent for > 2 years, sometimes longer if > 300 000 islets are successfully transplanted. Yet, this approach to chronic pancreatitis is underemphasized in the general medical and surgical literature and vastly underused in the United States. This review emphasizes the history and metabolic outcomes of TP/IAT and considers its usefulness in the context of other, more frequently used approaches, such as operative intervention with partial pancreatectomy and/or lateral pancreaticojejunostomy (Puestow procedure), as well as endoscopic retrograde cholangiopancreatography with pancreatic duct modification and stent placement. Distal pancreatectomy and Puestow procedures compromise isolation of islet mass, and adversely affect islet autotransplant outcomes. Therefore, when endoscopic measures fail to relieve pain in severe chronic pancreatitis, we recommend early intervention with TP/IAT.

Potent induction immunotherapy promotes long-term insulin independence after islet transplantation in type 1 diabetes

The seemingly inexorable decline in insulin independence after islet transplant alone (ITA) has raised concern about its clinical utility. We hypothesized that induction immunosuppression therapy determines durability of insulin independence. We analyzed the proportion of insulin-independent patients following final islet infusion in four groups of ITA recipients according to induction immunotherapy: University of Minnesota recipients given FcR nonbinding anti-CD3 antibody alone or T cell depleting antibodies (TCDAb) and TNF-α inhibition (TNF-α-i) (group 1; n = 29); recipients reported to the Collaborative Islet Transplant Registry (CITR) given TCDAb+TNF-α-i (group 2; n = 20); CITR recipients given TCDAb without TNF-α-i (group 3; n = 43); and CITR recipients given IL-2 receptor antibodies (IL-2RAb) alone (group 4; n = 177). Results were compared with outcomes in pancreas transplant alone (PTA) recipients reported to the Scientific Registry of Transplant Recipients (group 5; n = 677). The 5-year insulin independence rates in group 1 (50%) and group 2 (50%) were comparable to outcomes in PTA (group 5: 52%; p>>0.05) but significantly higher than in group 3 (0%; p = 0.001) and group 4 (20%; p = 0.02). Induction immunosuppression was significantly associated with 5-year insulin independence (p = 0.03), regardless of maintenance immunosuppression or other factors. These findings support potential for long-term insulin independence after ITA using potent induction therapy, with anti-CD3 Ab or TCDAb+TNF-α-i.

Total pancreatectomy and islet autotransplantation for chronic pancreatitis

BACKGROUND

Total pancreatectomy (TP) with intraportal islet autotransplantation (IAT) can relieve pain and preserve β-cell mass in patients with chronic pancreatitis (CP) when other therapies fail. We report on a >30-year single-center series.

STUDY DESIGN

Four hundred and nine patients (including 53 children, 5 to 18 years) with CP underwent TP-IAT from February 1977 to September 2011 (etiology: idiopathic, 41%; Sphincter of Oddi dysfunction/biliary, 9%; genetic, 14%; divisum, 17%; alcohol, 7%; and other, 12%; mean age was 35.3 years, 74% were female; 21% has earlier operations, including 9% Puestow procedure, 6% Whipple, 7% distal pancreatectomy, and 2% other). Islet function was classified as insulin independent for those on no insulin; partial, if known C-peptide positive or euglycemic on once-daily insulin; and insulin dependent if on standard basal-bolus diabetic regimen. A 36-item Short Form (SF-36) survey for quality of life was completed by patients before and in serial follow-up since 2007, with an integrated survey that was added in 2008.

RESULTS

Actuarial patient survival post TP-IAT was 96% in adults and 98% in children (1 year) and 89% and 98% (5 years). Complications requiring relaparotomy occurred in 15.9% and bleeding (9.5%) was the most common complication. IAT function was achieved in 90% (C-peptide >0.6 ng/mL). At 3 years, 30% were insulin independent (25% in adults, 55% in children) and 33% had partial function. Mean hemoglobin A1c was <7.0% in 82%. Earlier pancreas surgery lowered islet yield (2,712 vs 4,077/kg; p = 0.003). Islet yield (<2,500/kg [36%]; 2,501 to 5,000/kg [39%]; >5,000/kg [24%]) correlated with degree of function with insulin-independent rates at 3 years of 12%, 22%, and 72%, and rates of partial function 33%, 62%, and 24%. All patients had pain before TP-IAT and nearly all were on daily narcotics. After TP-IAT, 85% had pain improvement. By 2 years, 59% had ceased narcotics. All children were on narcotics before, 39% at follow-up; pain improved in 94%; and 67% became pain-free. In the SF-36 survey, there was significant improvement from baseline in all dimensions, including the Physical and Mental Component Summaries (p < 0.01), whether on narcotics or not.

CONCLUSIONS

TP can ameliorate pain and improve quality of life in otherwise refractory CP patients, even if narcotic withdrawal is delayed or incomplete because of earlier long-term use. IAT preserves meaningful islet function in most patients and substantial islet function in more than two thirds of patients, with insulin independence occurring in one quarter of adults and half the children.

Total pancreatectomy and islet autotransplantation for chronic pancreatitis

BACKGROUND

Total pancreatectomy (TP) with intraportal islet autotransplantation (IAT) can relieve pain and preserve β-cell mass in patients with chronic pancreatitis (CP) when other therapies fail. We report on a >30-year single-center series.

STUDY DESIGN

Four hundred and nine patients (including 53 children, 5 to 18 years) with CP underwent TP-IAT from February 1977 to September 2011 (etiology: idiopathic, 41%; Sphincter of Oddi dysfunction/biliary, 9%; genetic, 14%; divisum, 17%; alcohol, 7%; and other, 12%; mean age was 35.3 years, 74% were female; 21% has earlier operations, including 9% Puestow procedure, 6% Whipple, 7% distal pancreatectomy, and 2% other). Islet function was classified as insulin independent for those on no insulin; partial, if known C-peptide positive or euglycemic on once-daily insulin; and insulin dependent if on standard basal-bolus diabetic regimen. A 36-item Short Form (SF-36) survey for quality of life was completed by patients before and in serial follow-up since 2007, with an integrated survey that was added in 2008.

RESULTS

Actuarial patient survival post TP-IAT was 96% in adults and 98% in children (1 year) and 89% and 98% (5 years). Complications requiring relaparotomy occurred in 15.9% and bleeding (9.5%) was the most common complication. IAT function was achieved in 90% (C-peptide >0.6 ng/mL). At 3 years, 30% were insulin independent (25% in adults, 55% in children) and 33% had partial function. Mean hemoglobin A1c was <7.0% in 82%. Earlier pancreas surgery lowered islet yield (2,712 vs 4,077/kg; p = 0.003). Islet yield (<2,500/kg [36%]; 2,501 to 5,000/kg [39%]; >5,000/kg [24%]) correlated with degree of function with insulin-independent rates at 3 years of 12%, 22%, and 72%, and rates of partial function 33%, 62%, and 24%. All patients had pain before TP-IAT and nearly all were on daily narcotics. After TP-IAT, 85% had pain improvement. By 2 years, 59% had ceased narcotics. All children were on narcotics before, 39% at follow-up; pain improved in 94%; and 67% became pain-free. In the SF-36 survey, there was significant improvement from baseline in all dimensions, including the Physical and Mental Component Summaries (p < 0.01), whether on narcotics or not.

CONCLUSIONS

TP can ameliorate pain and improve quality of life in otherwise refractory CP patients, even if narcotic withdrawal is delayed or incomplete because of earlier long-term use. IAT preserves meaningful islet function in most patients and substantial islet function in more than two thirds of patients, with insulin independence occurring in one quarter of adults and half the children.

Comparison of recipient outcomes following transplant from local versus imported pancreas donors

The shortage of deceased donor organs for solid organ transplantation continues to be an ongoing dilemma. One approach to increase the number of pancreas transplants is to share organs between procurement regions. To assess for the effects of organ importation, we reviewed the outcomes of 1014 patients undergoing deceased donor pancreas transplant at a single center. We performed univariate and multivariate analyses of the association of donor, recipient and surgical characteristics with patient outcomes. Organ importation had no effect on graft or recipient survival for recipients of solitary pancreas transplants. Similarly, there was no effect on technical failure rate, graft survival or long-term patient survival for simultaneous kidney-pancreas (SPK) recipients. In contrast, there was a significant and independent increased risk of death in the first year in SPK recipients of imported organs. SPK recipients had longer hospitalizations and increased hospital costs. This increased medical complexity may make these patients more susceptible to short-term complications resulting from the longer preservation times of import transplants. These findings support the continued use of organ sharing to reduce transplant wait times but highlight the importance of strategies to reduce organ preservation times.

Ten-year outcome after rapid discontinuation of prednisone in adult primary kidney transplantation

BACKGROUND AND OBJECTIVES

Rapid discontinuation of prednisone after kidney transplantation potentially allows for minimization of steroid-related side effects. Although intermediate-term data with rapid discontinuation of prednisone have been promising, concern still exists regarding long-term outcomes. The 10-year experience is reported herein.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Between October 1, 1999 and December 31, 2010, 1241 adult primary kidney transplants (791 living donor and 450 deceased donor) were performed using a protocol in which prednisone is discontinued after postoperative day 5. The 10-year actuarial recipient and graft survival rates and prednisone-related side effects were studied.

RESULTS

Ten-year actuarial patient survival was 71% for living donor transplants and 62% for deceased donor transplants; 10-year graft survival was 61% for living donor transplants and 51% for deceased donor transplants, and was comparable to 10-year Scientific Registry of Transplant Recipients national data. Ten-year death-censored graft survival was 79% for living donor transplants and 80% for deceased donor transplants. Ten-year acute rejection rates were 25% for deceased donor transplants and 31% for living donor transplants; 10-year chronic rejection (interstitial fibrosis/tubular atrophy) rates were 39% for deceased donor transplants and 47% for living donor transplants. For nondiabetic recipients of living donor or deceased donor allografts, the incidence of new-onset diabetes was significantly lower than in historical controls on prednisone (P<0.001). We also found significantly reduced rates of cataracts, avascular necrosis, and cytomegalovirus infection in some subgroups.

CONCLUSIONS

Prednisone-related side effects can be minimized in a protocol incorporating rapid discontinuation of prednisone for maintenance immunosuppression. Ten-year patient and graft outcomes remain acceptable.

Guidelines for the diagnosis of antibody-mediated rejection in pancreas allografts-updated Banff grading schema

The first Banff proposal for the diagnosis of pancreas rejection (Am J Transplant 2008; 8: 237) dealt primarily with the diagnosis of acute T-cell-mediated rejection (ACMR), while only tentatively addressing issues pertaining to antibody-mediated rejection (AMR). This document presents comprehensive guidelines for the diagnosis of AMR, first proposed at the 10th Banff Conference on Allograft Pathology and refined by a broad-based multidisciplinary panel. Pancreatic AMR is best identified by a combination of serological and immunohistopathological findings consisting of (i) identification of circulating donor-specific antibodies, and histopathological data including (ii) morphological evidence of microvascular tissue injury and (iii) C4d staining in interacinar capillaries. Acute AMR is diagnosed conclusively if these three elements are present, whereas a diagnosis of suspicious for AMR is rendered if only two elements are identified. The identification of only one diagnostic element is not sufficient for the diagnosis of AMR but should prompt heightened clinical vigilance. AMR and ACMR may coexist, and should be recognized and graded independently. This proposal is based on our current knowledge of the pathogenesis of pancreas rejection and currently available tools for diagnosis. A systematized clinicopathological approach to AMR is essential for the development and assessment of much needed therapeutic interventions.

Richard Carlton Lillehei: transplant and shock surgical pioneer

Richard Carlton Lillehei (1927-1981) was a trainee of the Minnesota School of Surgery under Owen H. Wangensteen in the early 1950s, when great advances were being accomplished in cardiac surgery. His mentors besides Wangensteen included his brother C. Walton Lillehei, Richard L. Varco, and several others in the Department of Surgery. His interest in surgical research was evident since the early part of his training. The understanding of the nature and management of shock occupied his attention and persisted all his life. Equally, his studies on organ preservation and intestinal and pancreatic transplantation were classic in the evolution of surgery. In fact, Rich Lillehei, together with William Kelly, performed the world's first clinical pancreas transplant in 1966 and with his own team, the world's first clinical small bowel transplantation in 1967. Following that, these two areas of transplantation progressively advanced to be applied to thousands of patients worldwide. Lillehei was also a committed teacher and many of his students are disseminated throughout the globe. Unfortunately, his enormous contributions were cut short with his premature death at age 53. However, his surgical legacy remains alive!

Surgical protocol involving the infusion of paramagnetic microparticles for preferential incorporation within porcine islets

INTRODUCTION

Despite significant advances, widespread applicability of islet cell transplantation remains elusive. Refinement of current islet isolation protocols may improve transplant outcomes. Islet purification by magnetic separation has shown early promise. However, surgical protocols must be optimized to maximize the incorporation of paramagnetic microparticles (MP) within a greater number of islets. This study explores the impact of MP concentration and infusion method on optimizing MP incorporation within islets.

METHODS

Five porcine pancreata were procured from donors after cardiac death. Splenic lobes were isolated and infused with varying concentrations of MP (8, 16, and 32 × 10(8) MP/L of cold preservation solution) and using one of two delivery techniques (hanging bag versus hand-syringe). After procurement and infusion, pancreata were stored at 0°C to 4°C during transportation (less than 1 hour), fixed in 10% buffered formalin, and examined by standard magnetic resonance imaging (MRI) and histopathology.

RESULTS

T2*-weighted MRI showed homogeneous distribution of MP in all experimental splenic lobes. In addition, histologic analysis confirmed that MP were primarily located within the microvasculature of islets (82% to 85%), with few MP present in acinar tissue (15% to 18%), with an average of five to seven MP per islet (within a 5-μm thick section). The highest MP incorporation was achieved at a concentration of 16 × 10(8) MP/L using the hand-syringe technique.

CONCLUSION

This preliminary study suggests that optimization of a surgical protocol, MP concentrations, and applied infusion pressures may enable more uniform distribution of MP in the porcine pancreas and better control of MP incorporation within islets. These results may have implications in maximizing the efficacy of islet purification by magnetic separation.

Prediction of pancreatic tissue densities by an analytical test gradient system before purification maximizes human islet recovery for islet autotransplantation/allotransplantation

BACKGROUND

Using standard density gradient (SDG) ranges for human islet purification frequently results in islet loss and transplantation of lower islet mass. Measuring the densities of islet and acinar tissue beforehand to customize the gradient range for the actual COBE 2991 cell processor (COBE) purification is likely to maximize the recovery of islets. We developed an analytical test gradient system (ATGS) for predicting pancreatic tissue densities before COBE purification to minimize islet loss during purification.

METHODS

Human islets were isolated from deceased donor (n=30) and chronic pancreatitis pancreata (n=30). Pancreatic tissue densities were measured before purification by the ATGS, and the density gradient range for islet purification in a COBE was customized based on density profiles determined by the ATGS. The efficiency of custom density gradients (CDGs) to recover high islet yield was compared with predefined SDGs.

RESULTS

Pancreatic tissue densities from autografts were significantly higher than in allograft preparations. In allograft purifications, a higher proportion of islets were recovered using ATGS-guided CDGs (85.9%±18.0%) compared with the SDG method (69.2%±27.0%; P=0.048). Acinar contamination at 60%, 70%, and 80% cumulative islet yield for allografts was significantly lower in the CDG group. In autograft purifications, more islets were recovered with CDGs (81.9%±28.0%) than SDGs (55.8%±22.8%; P=0.03). CDGs effectively reduced islet loss by minimizing islet sedimentation in the COBE bag.

CONCLUSIONS

Using ATGS-guided CDGs maximizes the islet recovery for successful transplantations by reducing acinar contamination in allograft preparations and by reducing sedimentation of islets in the COBE bag in autograft preparations.

Persufflation improves pancreas preservation when compared with the two-layer method

Islet transplantation is emerging as a promising treatment for patients with type 1 diabetes. It is important to maximize viable islet yield for each organ due to scarcity of suitable human donor pancreata, high cost, and the large dose of islets required for insulin independence. However, organ transport for 8 hours using the two-layer method (TLM) frequently results in low islet yields. Since efficient oxygenation of the core of larger organs (eg, pig, human) in TLM has recently come under question, we investigated oxygen persufflation as an alternative way to supply the pancreas with oxygen during preservation. Porcine pancreata were procured from donors after cardiac death and preserved by either TLM or persufflation for 24 hours and subsequently fixed. Biopsies collected from several regions of the pancreas were sectioned, stained with hematoxylin and eosin, and evaluated by a histologist. Persufflated tissues exhibited distended capillaries and significantly less autolysis/cell death relative to regions not exposed to persufflation or to tissues preserved with TLM. The histology presented here suggests that after 24 hours of preservation, persufflation dramatically improves tissue health when compared with TLM. These results indicate the potential for persufflation to improve viable islet yields and extend the duration of preservation, allowing more donor organs to be utilized.

Rapid quantitative assessment of the pig pancreas biopsy predicts islet yield

BACKGROUND

The cost of islet procurement from donor pigs is increased by the use of organs that produce low yields. We developed an assessment system using dithizone-stained pig pancreas biopsies to enable the preselection of donor organs.

METHODS

Pig pancreas biopsy slices were soaked in dithizone solution. The islets were evaluated before islet isolation by converting the islet counts (IC) to islet equivalents (IE), and then determining the IE/cm(2), IE/IC, % islets >150 microm, and % islets >200 microm. These parameters were evaluated in 3 different areas of the pancreas (duodenal, splenic, and connecting lobe; n = 42 each). Stepwise multivariate linear regression analysis was performed to assess for correlations with islet yield and decide which area of the pancreas had the most predictive value. To identify other predictors, including donor and islet isolation variables, we performed binary logistic regression analysis with significant variables from the univariate analysis (n = 67). For this analysis, the pigs were categorized into high (n = 23) and low (n = 44) yield groups.

RESULTS

Stepwise multivariate linear regression analysis revealed that IE/cm(2) of the splenic lobe significantly predicted islet yield. Binary logistic regression analysis indicated that the IE/mm(2) of the splenic lobe was the only parameter that significantly correlated with successful pig islet isolations (P = .01; odds ratio 3.605). Variables associated with donor and islet isolation, such as age, gender, ischemic time, or enzyme lot, were not significantly correlated with islet yield.

CONCLUSION

Our study suggests that the islet distribution of splenic lobe biopsies can be a reliable predictor of islet yield from pig pancreata.

Pancreas oxygen persufflation increases ATP levels as shown by nuclear magnetic resonance

BACKGROUND

Islet transplantation is a promising treatment for type 1 diabetes. Due to a shortage of suitable human pancreata, high cost, and the large dose of islets presently required for long-term diabetes reversal; it is important to maximize viable islet yield. Traditional methods of pancreas preservation have been identified as suboptimal due to insufficient oxygenation. Enhanced oxygen delivery is a key area of improvement. In this paper, we explored improved oxygen delivery by persufflation (PSF), ie, vascular gas perfusion.

METHODS

Human pancreata were obtained from brain-dead donors. Porcine pancreata were procured by en bloc viscerectomy from heparinized donation after cardiac death donors and were either preserved by either two-layer method (TLM) or PSF. Following procurement, organs were transported to a 1.5-T magnetic resonance (MR) system for (31)P nuclear magnetic resonance spectroscopy to investigate their bioenergetic status by measuring the ratio of adenosine triphosphate to inorganic phosphate (ATP:P(i)) and for assessing PSF homogeneity by MRI.

RESULTS

Human and porcine pancreata can be effectively preserved by PSF. MRI showed that pancreatic tissue was homogeneously filled with gas. TLM can effectively raise ATP:P(i) levels in rat pancreata but not in larger porcine pancreata. ATP:P(i) levels were almost undetectable in porcine organs preserved with TLM. When human or porcine organs were preserved by PSF, ATP:P(i) was elevated to levels similar to those observed in rat pancreata.

CONCLUSION

The methods developed for human and porcine pancreas PSF homogeneously deliver oxygen throughout the organ. This elevates ATP levels during preservation and may improve islet isolation outcomes while enabling the use of marginal donors, thus expanding the usable donor pool.

Continuous real-time viability assessment of kidneys based on oxygen consumption

BACKGROUND

Current ex vivo quality assessment of donor kidneys is limited to vascular resistance measurements and histological analysis. New techniques for the assessment of organ quality before transplantation may further improve clinical outcomes while expanding the depleted deceased-donor pool. We propose the measurement of whole organ oxygen consumption rate (WOOCR) as a method to assess the quality of kidneys in real time before transplantation.

METHODS

Five porcine kidneys were procured using a donation after cardiac death (DCD) model. The renal artery and renal vein were cannulated and the kidney connected to a custom-made hypothermic machine perfusion (HMP) system equipped with an inline oxygenator and fiber-optic oxygen sensors. Kidneys were perfused at 8 degrees C, and the perfusion parameters and partial oxygen pressures (pO(2)) were measured to calculate WOOCR.

RESULTS

Without an inline oxygenator, the pO(2) of the perfusion solution at the arterial inlet and venous outlet diminished to near 0 within minutes. However, once adequate oxygenation was provided, a significant pO(2) difference was observed and used to calculate the WOOCR. The WOOCR was consistently measured from presumably healthy kidneys, and results suggest that it can be used to differentiate between healthy and purposely damaged organs.

CONCLUSIONS

Custom-made HMP systems equipped with an oxygenator and inline oxygen sensors can be applied for WOOCR measurements. We suggest that WOOCR is a promising approach for the real-time quality assessment of kidneys and other organs during preservation before transplantation.

Tacrolimus and cyclosporine nephrotoxicity in native kidneys of pancreas transplant recipients

BACKGROUND AND OBJECTIVES

Calcineurin inhibitors, while representing advances for solid organ transplantation, have nephrotoxic potential that reduces their net benefit. Tacrolimus has been considered less nephrotoxic than cyclosporine, but direct quantitative comparisons of the changes in renal structure from baseline to follow-up biopsies have not been done. To avoid the pitfalls of renal allograft studies, including rejection and disease recurrence, we compared the development of calcineurin lesions in the native kidneys of 14 tacrolimus- and 12 calcineurin-treated pancreas transplant alone recipients cured of type 1 diabetes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Research renal biopsies obtained before and at 5 years after transplantation were studied using established morphometric methods.

RESULTS

The cyclosporine and tacrolimus groups had, respectively, on average, 33% versus 44% decline in GFR (ns), 27% versus 29% increase in cortical interstitial fractional volume (ns), 245% versus 347% increase in the fractional volume of cortical tubules that were atrophic (ns), and 291% versus 392% increase in the percent of globally sclerotic glomeruli (ns). Arteriolar hyalinosis did not change significantly in either group.

CONCLUSIONS

These studies indicate that the nephrotoxic potential of tacrolimus and cyclosporine are equivalent and support the development of strategies to reduce these negative effects.

Pediatric islet autotransplantation: indication, technique, and outcome

Chronic pancreatitis is a rare disease in childhood. However, when severe, a total pancreatectomy may be the only option to relieve pain and restore quality of life. An islet autotransplant performed at the time of pancreatectomy can prevent or minimize the postsurgical diabetes that would otherwise result from pancreatectomy alone. In this procedure, the resected pancreas is mechanically disrupted and enzymatically digested to separate the islets from the surrounding exocrine tissue, and the isolated islets are infused into the portal vein and engraft in the liver. Because patients are receiving their own tissue, no immunosuppression is required. Islet autotransplant is successful in two thirds of children-these patients are insulin independent or require little insulin to maintain euglycemia. Factors associated with a more successful outcome include a younger age at transplant (<13 years), more islets transplanted, and lack of prior surgical procedures on the pancreas (partial pancreatectomy or surgical drainage procedures).

Pancreas after living donor kidney transplants in diabetic patients: impact on long-term kidney graft function

In this single-institution study, we compared outcomes in diabetic recipients of living donor (LD) kidney transplants that did vs. did not undergo a subsequent pancreas transplant. Of 307 diabetic recipients who underwent LD kidney transplants from January 1, 1995, through December 31, 2003, a total of 175 underwent a subsequent pancreas after kidney (PAK) transplant; 75 were deemed eligible (E) for, but did not receive (for personal or financial reasons), a PAK, and thus had a kidney transplant alone (KTA); and 57 deemed ineligible (I) for a PAK because of comorbidity also had just a KTA. We analyzed the three groups (PAK, KTA-E, KTA-I) for differences in patient characteristics, glycemic control, renal function, patient and kidney graft survival rates, and causes of death. Kidney graft survival rates (actuarial) were similar in the PAK vs. KTA-E groups at one, five, and 10 yr post-transplant: 98%, 82%, and 67% (PAK) vs. 100%, 84%, and 62% (KTA-E) (p = 0.9). The long-term (greater than four yr post-transplant) estimated glomerular filtration rate (GFR) was higher in the PAK than in the KTA-E group: 53 +/- 20 mL/min (PAK) vs. 43 +/- 16 mL/min (KTA-E) (p = 0.016). The patient survival rates were also similar for the PAK and KTA-E groups. We conclude that the subsequent transplant of a pancreas after an LD kidney transplant does not adversely affect patient or kidney graft survival rates; in fact, it is associated with better long-term kidney graft function.

Selective retransplant after graft loss to nonadherence: success with a second chance

Nonadherence (NA) is a difficult posttransplant problem that can lead to graft loss. A retransplant is controversial because of a fear of recurrent NA. We reviewed our center's data base and identified 114 kidney recipients who lost their graft to overt NA; of this group, 35 (31%) underwent a retransplant after a thorough reevaluation. We compared this NA retransplant group to a control group of second transplant recipients who did not lose their first graft to overt NA (non-NA) (n = 552). After 8 years of follow-up, we found no significant differences between the groups in actuarial graft or patient survival rates, renal function, or the incidence of biopsy-proven chronic rejection. However, 5 of 35 (14%) NA recipients versus 10 of 552 (2%) non-NA recipients lost their retransplant to NA (p = 0.0001). Twenty of 35 (57%) of the NA group exhibited repeat NA behavior after retransplant. We conclude that prior graft loss to NA is associated with increased graft loss to NA after retransplant. However, the majority of NA retransplant recipients did well-with overall long-term outcomes similar to those of the non-NA group. With careful patient selection and aggressive intervention, prior overt NA should not be an absolute contraindication to retransplantation.

Pancreas transplantation

Since the introduction of pancreas transplantation more than 40 years ago, efforts to develop more minimally invasive techniques for endocrine replacement therapy have been in progress, yet this surgical procedure still remains the treatment of choice for diabetic patients with end-stage renal failure. Many improvements have been made in the surgical techniques and immunosuppressive regimens, both of which have contributed to an increasing number of indications for pancreas transplantation. This operation can be justified on the basis that patients replace daily injections of insulin with an improved quality of life but at the expense of a major surgical procedure and lifelong immunosuppression. The various indications, categories, and outcomes of patients having a pancreas transplant are discussed, particularly with reference to the effect on long-term diabetic complications.