Human islet isolation for autologous transplantation: comparison of yield and function using SERVA/Nordmark versus Roche enzymes

Current status of total pancreatectomy with islet autotransplantation for chronic and recurrent acute pancreatitis

Total pancreatectomy with islet autotransplantation (TPIAT) is an established and effective treatment modality for patients diagnosed with intractable chronic pancreatitis (CP) and recurrent acute pancreatitis (RAP). TPIAT primarily aims to manage debilitating pain leading to impaired quality of life among patients with CP or RAP, which can be successfully managed with medical, endoscopic, or surgical interventions. TPIAT is significantly successful in relieving pain associated with CP and improving health-related quality of life outcomes. Furthermore, the complete loss of pancreatic endocrine function attributed to total pancreatectomy (TP) can be compensated by autologous islet transplantation (IAT). Patients receiving IAT can achieve insulin independence or can be less dependent on exogenous insulin compared with those receiving TP alone. Historically, TPIAT has been mainly used in the United States, and its outcomes have been improving due to technological advancements. Despite some challenges, TPIAT can be a promising treatment for patients with CP-related intractable pain. Thus far, TPIAT is not commonly performed in Japan. Nevertheless, it may improve health-related quality of life in Japanese patients with CP, similar to Western patients. This review article aimed to provide an overview of the indications, related procedures, and outcomes of TPIAT and to discuss future prospects in Japan.

Hypoxia within subcutaneously implanted macroencapsulation devices limits the viability and functionality of densely loaded islets

Introduction

Subcutaneous macroencapsulation devices circumvent disadvantages of intraportal islet therapy. However, a curative dose of islets within reasonably sized devices requires dense cell packing. We measured internal PO2 of implanted devices, mathematically modeled oxygen availability within devices and tested the predictions with implanted devices containing densely packed human islets.

Methods

Partial pressure of oxygen (PO2) within implanted empty devices was measured by noninvasive 19F-MRS. A mathematical model was constructed, predicting internal PO2, viability and functionality of densely packed islets as a function of external PO2. Finally, viability was measured by oxygen consumption rate (OCR) in day 7 explants loaded at various islet densities.

Results

In empty devices, PO2 was 12 mmHg or lower, despite successful external vascularization. Devices loaded with human islets implanted for 7 days, then explanted and assessed by OCR confirmed trends proffered by the model but viability was substantially lower than predicted. Co-localization of insulin and caspase-3 immunostaining suggested that apoptosis contributed to loss of beta cells.

Discussion

Measured PO2 within empty devices declined during the first few days post-transplant then modestly increased with neovascularization around the device. Viability of islets is inversely related to islet density within devices.

Total Pancreatectomy with Islet Auto-Transplantation: Surgical Procedure, Outcomes, and Quality of Life

Chronic pancreatitis is a progressive and irreversible process of pancreatic inflammation and fibrosis that can lead to intractable abdominal pain and severely impaired quality of life (QoL). Often patients are refractory to standard medical or endoscopic treatments. Total pancreatectomy (TP) and islet auto-transplantation (TP-IAT) can offer pain relief to patients by removing the entire pancreas and the auto-transplant component ameliorates the resulting diabetes. QoL is significantly improved after TP-IAT when insulin independence is present. Recent data support offering TP-IAT rather than TP alone and treating with exogenous insulin for patients with debilitating chronic pancreatitis.

Safety and Clinical Outcomes of Using Low-Molecular-Weight Dextran During Islet Autotransplantation in Children

OBJECTIVES

The objective of this study was to evaluate potential safety and clinical benefit of low-molecular-weight dextran (dextran) use in patients undergoing total pancreatectomy with islet auto transplantation (TPIAT).

METHODS

We evaluated 124 children undergoing TPIAT at a single institution, either with (n = 72) or without (n = 52) perioperative dextran infusion. Data on islet graft function and postoperative complications were collected through electronic medical records and patient-reported outcomes from research questionnaires.

RESULTS

Islet graft failure was less likely at 1 year (odds ratio, 0.186; 95% confidence interval, 0.04-0.65) and 2 years (odds ratio, 0.063; 95% confidence interval, 0.003-0.35) post-TPIAT in the dextran group. This finding remained significant at 2 years in multivariate logistic regression modeling adjusting for islet mass, body surface area, and sex. Likewise, in multivariate regression, the odds of partial islet graft function were higher at 1 and 2 years in the dextran group. Dextran use was overall safe, although it did lead to a higher incidence of postoperative bleeding requiring blood transfusions (P < 0.001).

CONCLUSIONS

These findings suggest that dextran use may increase the likelihood for sustained post-TPIAT islet graft function, potentially mitigating severity of postoperative diabetes for these children.

Islet cell transplantation in children

This paper aims to provide an overview of islet cell transplantation in children, with specific attention to pediatric total pancreatectomy with islet autotransplantation (TPIAT). We will summarize the definition and causes of chronic pancreatitis in children, the TPIAT procedure and potential complications, the process of islet cell isolation and autotransplantation, and long-term results after TPIAT. Lastly, we will briefly discuss islet cell allotransplantation in the adult population and its potential role in treating children.

The role of total pancreatectomy with islet autotransplantation in the treatment of chronic pancreatitis: A report from the International Consensus Guidelines in chronic pancreatitis

BACKGROUND

Advances in our understanding of total pancreatectomy with islet autotransplantation (TPIAT) have been made. We aimed to define indications and outcomes of TPIAT.

METHODS

Expert physician-scientists from North America, Asia, and Europe reviewed the literature to address six questions selected by the writing group as high priority topics. A consensus was reached by voting on statements generated from the review.

RESULTS

Consensus statements were voted upon with strong agreement reached that (Q1) TPIAT may improve quality of life, reduce pain and opioid use, and potentially reduce medical utilization; that (Q3) TPIAT offers glycemic benefit over TP alone; that (Q4) the main indication for TPIAT is disabling pain, in the absence of certain medical and psychological contraindications; and that (Q6) islet mass transplanted and other disease features may impact diabetes mellitus outcomes. Conditional agreement was reached that (Q2) the role of TPIAT for all forms of CP is not yet identified and that head-to-head comparative studies are lacking, and that (Q5) early surgery is likely to improve outcomes as compared to late surgery.

CONCLUSIONS

Agreement on TPIAT indications and outcomes has been reached through this working group. Further studies are needed to answer the long-term outcomes and maximize efforts to optimize patient selection.

Laparoscopic-assisted versus open total pancreatectomy and islet autotransplantation: A case-matched study of pediatric patients

BACKGROUND

Total Pancreatectomy and Islet Autotransplantation (TPIAT) are a potential treatment for children with severe, refractory chronic pancreatitis. A laparoscopic-assisted approach provides a smaller incision and excellent visualization of the distal pancreas and spleen during resection. A minimally-invasive approach has proven advantageous for other pediatric procedures, but its value is unknown for this rare operation. This retrospective review compares outcomes between patients undergoing laparoscopic-assisted versus open TPIAT.

STUDY DESIGN

Children (n = 21) receiving laparoscopic-assisted TPIAT from 2013 to 2015 and children (n = 21) receiving open TPIAT from 2011 to 2015 were matched based on age, gender, symptom duration, previous interventions, and pancreatic fibrosis scores. Data reviewed included postoperative complications, operative time, estimated blood loss (EBL), intraoperative blood transfusions, number of islet equivalents (IEQ)/kg transplanted, hospital length-of-stay, graft function, narcotic use, and Patient Scar Assessment Questionnaire scores. Between-group differences were compared using Fisher's exact, Chi-square, and T-tests.

RESULTS

Surgical complications were similar between surgical groups (p = 0.35) and included wound complications (n = 11), chyle leak (n = 7), bowel obstruction (n = 5), bile leak (n = 3), gastrointestinal bleed (n = 2), and pneumonia (n = 1). There were no significant differences in operative time (p = 0.18), EBL (p = 0.96), blood transfusions (p = 0.34), IEQ/kg transplanted (p = 0.15), and hospital length-of-stay (p = 0.66). Insulin and opioid use was similar except for a slightly higher use of opioids (n = 4) at 2 years in the laparoscopic group. Patient surgical scar satisfaction was similar between groups (p = 0.26).

CONCLUSIONS

Outcomes for laparoscopic-assisted TPIAT appear comparable to open TPIAT. In children, a minimally-invasive approach does not compromise safety, effectiveness, or operative efficiency and may be used based on surgeon and patient preference.

Human pancreatic tissue dissociation enzymes for islet isolation: Advances and clinical perspectives

BACKGROUND AND AIMS

Successful clinical human allo or auto-islet transplantation requires the recovery of a sufficient number of functional islets from either brain-dead or chronic pancreatitis pancreases respectively.

METHODS

In the last two decades (2000-2019), significant progress has been made in improving the human islet isolation procedures and in standardizing the use of different tissue dissociation enzyme (TDE; a mixture of collagenase and protease enzymes) blends to recover higher islet yields.

RESULTS AND CONCLUSIONS

This review presents information focusing on properties and role of TDE blends during the islet isolation process, particularly emphasizing on the current developments, associated challenges and future perspectives within the field.

Geographical variance in reporting of elective surgery for chronic pancreatitis

The selection of optimum surgical procedure from the range of reported operations for chronic pancreatitis (CP) can be difficult. The aim of this study is to explore geographical variation in reporting of elective surgery for CP. A systematic search of the literature was performed using the Scopus database for reports of five selected procedures for CP: duodenum-preserving pancreatic head resection, total pancreatectomy with islet autotransplantation (TPIAT), Frey pancreaticojejunostomy, thoracoscopic splanchnotomy and the Izbicki V-shaped resection. The keyword and MESH heading 'chronic pancreatitis' was used. Overall, 144 papers met inclusion criteria and were utilized for data extraction. There were 33 reports of duodenum-preserving pancreatic head resection. Twenty-one (64%) were from Germany. There were 60 reports of TPIAT, 53 (88%) from the USA. There are only two reports of TPIAT from outwith the USA and UK. The 34 reports of the Frey pancreaticojejunostomy originate from 12 countries. There were 20 reports of thoracoscopic splanchnotomy originating from nine countries. All three reports of the Izbicki 'V' procedure are from Germany. There is geographical variation in reporting of surgery for CP. There is a need for greater standardization in the selection and reporting of surgery for patients with painful CP.

Evaluation of collagenase gold plus BP protease in isolating islets from human pancreata

Selection of enzymes for optimal pancreas digestion is essential for successful human islet isolations. The aim of this study was to evaluate the efficacy and outcome of using Collagenase Gold plus BP protease (VitaCyte) (n = 8) by comparing it to two commercially available enzymes, Liberase MTF C/T (Roche) (n = 48) and Collagenase NB1/NP (Serva) (n = 15). The isolation outcomes were assessed by islet counting, viability, glucose-stimulated oxygen consumption rate (OCR), and successful graft-rate following transplantation in diabetic NOD scid mice. The pancreas donor characteristics were not significantly different between the tested enzyme groups regarding their BMI, pancreas weight, cold ischemia time (CIT) and HbA1c. The results show that digested tissue volume was not statistically significant between the VitaCyte enzyme (34.25 ± 5.4 mL) and the Roche enzyme (55.25 ± 3.42 mL, p = 0.073), however, this was significant with Serva enzyme (64.07 ± 7.95 mL, p = 0.020). Interestingly, the islet yields were not statistically different between all enzyme groups. Moreover, when islets were transplanted into NOD scid mice, the reversal rate of diabetes for the VitaCyte enzyme group was similar to all enzyme groups. In conclusion, the effectiveness of Collagenase Gold plus BP protease is comparable to the MTF C/T and the Collagenase NB1/NP enzymes; the low cost could facilitate the use of more pancreata for islet isolations.

Autologous Mesenchymal Stem Cell and Islet Cotransplantation: Safety and Efficacy

Islet engraftment after transplantation is impaired by high rates of islet/β cell death caused by cellular stressors and poor graft vascularization. We studied whether cotransplantation of ex vivo expanded autologous bone marrow-derived mesenchymal stem cells (MSCs) with islets is safe and beneficial in chronic pancreatitis patients undergoing total pancreatectomy with islet autotransplantation. MSCs were harvested from the bone marrow of three islet autotransplantation patients and expanded at our current Good Manufacturing Practices (cGMP) facility. On the day of islet transplantation, an average dose of 20.0 ± 2.6 ×106 MSCs was infused with islets via the portal vein. Adverse events and glycemic control at baseline, 6, and 12 months after transplantation were compared with data from 101 historical control patients. No adverse events directly related to the MSC infusions were observed. MSC patients required lower amounts of insulin during the peritransplantation period (p = .02 vs. controls) and had lower 12-month fasting blood glucose levels (p = .02 vs. controls), smaller C-peptide declines over 6 months (p = .01 vs. controls), and better quality of life compared with controls. In conclusion, our pilot study demonstrates that autologous MSC and islet cotransplantation may be a safe and potential strategy to improve islet engraftment after transplantation. (Clinicaltrials.gov registration number: NCT02384018). Stem Cells Translational Medicine 2018;7:11-19.

Operative management of chronic pancreatitis: A review

BACKGROUND

Pain secondary to chronic pancreatitis is a difficult clinical problem to manage. Many patients are treated medically or undergo endoscopic therapy and surgical intervention is often reserved for those who have failed to gain adequate pain relief from a more conservative approach.

RESULTS

There have been a number of advances in the operative management of chronic pancreatitis over the last few decades and current therapies include drainage procedures (pancreaticojejunostomy, etc.), resection (pancreticoduodenectomy, etc.) and combined drainage/resection procedures (Frey procedure, etc.). Additionally, many centers currently perform total pancreatectomy with islet autotransplantation, in addition to minimally invasive options that are intended to tailor therapy to individual patients.

DISCUSSION

Operative management of chronic pancreatitis often improves quality of life, and is associated with low rates of morbidity and mortality. The decision as to which procedure is optimal for each patient should be based on a combination of pathologic changes, prior interventions, and individual surgeon and center experience.

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.

Factors Predicting Outcomes After a Total Pancreatectomy and Islet Autotransplantation Lessons Learned From Over 500 Cases

OBJECTIVE

Our objective was to analyze factors predicting outcomes after a total pancreatectomy and islet autotransplantation (TP-IAT).

BACKGROUND

Chronic pancreatitis (CP) is increasingly treated by a TP-IAT. Postoperative outcomes are generally favorable, but a minority of patients fare poorly.

METHODS

In our single-centered study, we analyzed the records of 581 patients with CP who underwent a TP-IAT. Endpoints included persistent postoperative "pancreatic pain" similar to preoperative levels, narcotic use for any reason, and islet graft failure at 1 year.

RESULTS

In our patients, the duration (mean ± SD) of CP before their TP-IAT was 7.1 ± 0.3 years and narcotic usage of 3.3 ± 0.2 years. Pediatric patients had better postoperative outcomes. Among adult patients, the odds of narcotic use at 1 year were increased by previous endoscopic retrograde cholangiopancreatography (ERCP) and stent placement, and a high number of previous stents (>3). Independent risk factors for pancreatic pain at 1 year were pancreas divisum, previous body mass index >30, and a high number of previous stents (>3). The strongest independent risk factor for islet graft failure was a low islet yield-in islet equivalents (IEQ)-per kilogram of body weight. We noted a strong dose-response relationship between the lowest-yield category (<2000 IEQ) and the highest (≥5000 IEQ or more). Islet graft failure was 25-fold more likely in the lowest-yield category.

CONCLUSIONS

This article represents the largest study of factors predicting outcomes after a TP-IAT. Preoperatively, the patient subgroups we identified warrant further attention.

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.

Is Total Pancreatectomy with Islet Autotransplantation A Reasonable Choice for Pediatric Pancreatitis?

Chronic pancreatitis is an emerging and poorly understood disease in childhood. Total pancreatectomy with islet cell autotransplantation is being proposed as a treatment for chronic pancreatitis and recent studies report a more favorable outcome in children compared to adults. Herein, we review the therapeutic alternatives for pediatric chronic pancreatitis, focusing primarily on TP/IAT.

The Choice of Enzyme for Human Pancreas Digestion is a Critical Factor for Increasing the Success of Islet Isolation

BACKGROUND

We evaluated three commercially available enzymes for pancreatic digestion by comparing key parameters during the islet isolation process, as well as islet quality post-isolation.

METHODS

Retrospectively compared and analyzed islet isolations from pancreata using three different enzyme groups: Liberase HI (n=63), Collagenase NB1/Neutral Protease (NP) (n=43), and Liberase Mammalian Tissue Free Collagenase/Thermolysin (MTF C/T) (n=115). A standardized islet isolation and purification method was used. Islet quality assessment was carried out using islet count, viability, in vitro glucose-stimulated insulin secretion (GSIS), glucose-stimulated oxygen consumption rate (ΔOCR), and in vivo transplantation model in mice.

RESULTS

Donor characteristics were not significantly different among the three enzyme groups used in terms of age, sex, hospital stay duration, cause of death, body mass index (BMI), hemoglobin A1c (HbA1c), cold ischemia time (CIT), and pancreas weight. Digestion efficacy (percentage of digested tissue by weight) was significantly higher in the Liberase MTF C/T group (73.5 ± 1.5 %) when compared to the Liberase HI group (63.6 ± 2.3 %) (p<0.001) and the Collagenase NB1/NP group (61.7 ± 2.9%) (p<0.001). The stimulation index for GSIS was significantly higher in the Liberase MTF C/T group (5.3 ± 0.5) as compared to the Liberase HI (2.9 ± 0.2) (p<0.0001) and the Collagenase NB1/NP (3.6 ± 2.9) (p=0.012) groups. Furthermore, the Liberase MTF C/T enzymes showed the highest success rate of transplantation in diabetic NOD Scid mice (65%), which was significantly higher than the Liberase HI (42%, p=0.001) and the Collagenase NB1/NP enzymes (41%, p<0.001).

CONCLUSIONS

Liberase MTF C/T is superior to Liberase HI and Collagenase NB1/NP in terms of digestion efficacy and glucose-stimulated insulin secretion in vitro. Moreover, Liberase MTF C/T had a significantly higher success rate of transplantation in diabetic NOD Scid mice compared to Liberase HI and Collagenase NB1/NP enzymes.

Total pancreatectomy with islet autotransplantation: summary of an NIDDK workshop

A workshop sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases focused on research gaps and opportunities in total pancreatectomy with islet autotransplantation (TPIAT) for the management of chronic pancreatitis. The session was held on July 23, 2014 and structured into 5 sessions: (1) patient selection, indications, and timing; (2) technical aspects of TPIAT; (3) improving success of islet autotransplantation; (4) improving outcomes after total pancreatectomy; and (5) registry considerations for TPIAT. The current state of knowledge was reviewed; knowledge gaps and research needs were specifically highlighted. Common themes included the need to identify which patients best benefit from and when to intervene with TPIAT, current limitations of the surgical procedure, diabetes remission and the potential for improvement, opportunities to better address pain remission, GI complications in this population, and unique features of children with chronic pancreatitis considered for TPIAT. The need for a multicenter patient registry that specifically addresses the complexities of chronic pancreatitis and total pancreatectomy outcomes and postsurgical diabetes outcomes was repeatedly emphasized.

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.

Total pancreatectomy with islet autotransplantation: summary of a National Institute of Diabetes and Digestive and Kidney diseases workshop

A workshop sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases focused on research gaps and opportunities in total pancreatectomy with islet autotransplantation (TPIAT) for the management of chronic pancreatitis (CP). The session was held on July 23, 2014, and structured into 5 sessions: (1) patient selection, indications, and timing; (2) technical aspects of TPIAT; (3) improving success of islet autotransplantation; (4) improving outcomes after total pancreatectomy; and (5) registry considerations for TPIAT. The current state of knowledge was reviewed; knowledge gaps and research needs were specifically highlighted. Common themes included the need to identify which patients best benefit from and when to intervene with TPIAT, current limitations of the surgical procedure, diabetes remission and the potential for improvement, opportunities to better address pain remission, gastrointestinal complications in this population, and unique features of children with CP considered for TPIAT. The need for a multicenter patient registry that specifically addresses the complexities of CP and total pancreatectomy outcomes as well as postsurgical diabetes outcomes was repeatedly emphasized.

Total pancreatectomy with islet autotransplantation: summary of a National Institute of Diabetes and Digestive and Kidney diseases workshop

A workshop sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases focused on research gaps and opportunities in total pancreatectomy with islet autotransplantation (TPIAT) for the management of chronic pancreatitis (CP). The session was held on July 23, 2014, and structured into 5 sessions: (1) patient selection, indications, and timing; (2) technical aspects of TPIAT; (3) improving success of islet autotransplantation; (4) improving outcomes after total pancreatectomy; and (5) registry considerations for TPIAT. The current state of knowledge was reviewed; knowledge gaps and research needs were specifically highlighted. Common themes included the need to identify which patients best benefit from and when to intervene with TPIAT, current limitations of the surgical procedure, diabetes remission and the potential for improvement, opportunities to better address pain remission, gastrointestinal complications in this population, and unique features of children with CP considered for TPIAT. The need for a multicenter patient registry that specifically addresses the complexities of CP and total pancreatectomy outcomes as well as postsurgical diabetes outcomes was repeatedly emphasized.

Human Pancreatic Islets Isolated From Donors With Elevated HbA1c Levels: Islet Yield and Graft Efficacy

The aim of this study was to investigate the effects of elevated donor HbA1c levels (type 2 diabetes, T2D) on the islet yield and functionality postisolation. In this retrospective analysis, donors for islet isolations were classified into two groups: T2D group (HbA1c ≥ 6.5%, n = 18) and normal group (HbA1c < 6.5%, n = 308). Optimum pancreas digestion time (switch time) was significantly higher in the T2D group compared to the normal group (13.7 ± 1.2 vs. 11.7 ± 0.1 min, respectively, p = 0.005). Islet yields were significantly lower in the T2D group compared to the control (T2D vs. control): islet equivalent (IEQ)/g (prepurification 2,318 ± 195 vs. 3,713 ± 114, p = 0.003; postpurification 1,735 ± 175 vs. 2,663 ± 89, p = 0.013) and islet particle number (IPN)/g (prepurification, 2,519 ± 336 vs. 4,433 ± 143, p = 0.001; postpurification, 1,760 ± 229 vs. 2,715 ± 85, p = 0.007). Islets from T2D pancreata had significantly lower viability (T2D vs.

CONTROL

91.9 ± 1.6 vs. 94.4 ± 0.3%, p = 0.004) and decreased oxygen consumption rate (ΔOCR) (T2D vs.

CONTROL

0.09 ± 0.01 and 0.21 ± 0.03 nmol O2 100 islets(-1) min(-1), p = 0.049). The islets isolated from T2D donor pancreata reversed diabetes in NOD-SCID mice in 9% (2/22) compared to islets from control donor pancreata, which reversed diabetes in 67% (175/260, p < 0.001). In conclusion, this study demonstrates that elevated HbA1c (≥ 6.5%) is associated with impairment of islet function and lower islet yield; however, these islets could not be suitable for clinical applications.

Total pancreatectomy and islet autotransplantation in children for chronic pancreatitis: indication, surgical techniques, postoperative management, and long-term outcomes

OBJECTIVE

Describe the surgical technique, complications, and long-term outcomes of total pancreatectomy and islet autotransplantation (TP-IAT) in a large series of pediatric patients.

BACKGROUND

Surgical management of childhood pancreatitis is not clear; partial resection or drainage procedures often provide transient pain relief, but long-term recurrence is common due to the diffuse involvement of the pancreas. Total pancreatectomy (TP) removes the source of the pain, whereas islet autotransplantation (IAT) potentially can prevent or minimize TP-related diabetes.

METHODS

Retrospective review of 75 children undergoing TP-IAT for chronic pancreatitis who had failed medical, endoscopic, or surgical treatment between 1989 and 2012.

RESULTS

Pancreatitis pain and the severity of pain statistically improved in 90% of patients after TP-IAT (P < 0.001). The relief from narcotics was sustained. Of the 75 patients undergoing TP-IAT, 31 (41.3%) achieved insulin independence. Younger age (P = 0.032), lack of prior Puestow procedure (P = 0.018), lower body surface area (P = 0.048), higher islet equivalents (IEQ) per kilogram body weight (P = 0.001), and total IEQ (100,000) (P = 0.004) were associated with insulin independence. By multivariate analysis, 3 factors were associated with insulin independence after TP-IAT: (1) male sex, (2) lower body surface area, and (3) higher total IEQ per kilogram body weight. Total IEQ (100,000) was the single factor most strongly associated with insulin independence (odds ratio = 2.62; P < 0.001).

CONCLUSIONS

Total pancreatectomy and islet autotransplantation provides sustained pain relief and improved quality of life. The β-cell function is dependent on islet yield. Total pancreatectomy and islet autotransplantation is an effective therapy for children with painful pancreatitis that failed medical and/or endoscopic management.

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.

Metabolic assessment prior to total pancreatectomy and islet autotransplant: utility, limitations and potential

Islet autotransplant (IAT) may ameliorate postsurgical diabetes following total pancreatectomy (TP), but outcomes are dependent upon islet mass, which is unknown prior to pancreatectomy. We evaluated whether preoperative metabolic testing could predict islet isolation outcomes and thus improve assessment of TPIAT candidates. We examined the relationship between measures from frequent sample IV glucose tolerance tests (FSIVGTT) and mixed meal tolerance tests (MMTT) and islet mass in 60 adult patients, with multivariate logistic regression modeling to identify predictors of islet mass ≥2500 IEQ/kg. The acute C-peptide response to glucose (ACRglu) and disposition index from FSIVGTT correlated modestly with the islet equivalents per kilogram body weight (IEQ/kg). Fasting and MMTT glucose levels and HbA1c correlated inversely with IEQ/kg (r values -0.33 to -0.40, p ≤ 0.05). In multivariate logistic regression modeling, normal fasting glucose (<100 mg/dL) and stimulated C-peptide on MMTT ≥4 ng/mL were associated with greater odds of receiving an islet mass ≥2500 IEQ/kg (OR 0.93 for fasting glucose, CI 0.87-1.0; OR 7.9 for C-peptide, CI 1.75-35.6). In conclusion, parameters obtained from FSIVGTT correlate modestly with islet isolation outcomes. Stimulated C-peptide ≥4 ng/mL on MMTT conveyed eight times the odds of receiving ≥2500 IEQ/kg, a threshold associated with reasonable metabolic control postoperatively.

Severely fibrotic pancreases from young patients with chronic pancreatitis: evidence for a ductal origin of islet neogenesis

While it is known that islet cell mass increases considerably after birth, general uncertainty surrounds the source of new beta cells in humans. Chronic pancreatitis (CP) presents a natural injury model for studying postnatal beta-cell regeneration in the human pancreas. In this report, we present histological evidence from human CP pancreases to support the theory that islet neogenesis can occur from ductal precursor cells after birth. Three young patients (ages 16, 12, and 28 years) underwent total pancreatectomy for the management of CP followed by islet isolation and autologous transplantation to prevent or minimize postsurgical diabetes. In all cases, the pancreases had extensive fibrosis, a rock-like consistency, and calcifications in the ducts. During islet isolations, we observed the unusual release of islets with many ductal fragments. In histopathological evaluation of these pancreases, solid cords of cells sometimes formed islet like structures intraductally or extending from ductal structures. Immunofluorescence staining for chromogranin, insulin, proinsulin, PDX1, glucagon, and cytokeratins confirmed these structures to be composed of chromogranin-positive endocrine cells which included both β-cells and α-cells. Labeling for Ki67 to demonstrate mitotic activity showed frequent labeling of duct epithelial cells and of some periductal cells. Using insulin and wide-spectrum cytokeratin double immunofluorescent labeling, we found insulin-positive cells to be present within the ductal lumens, among the cytokeratin-positive ductal epithelium, and extending from the ductal epithelium into surrounding connective tissues, providing evidence for a ductal origin of islet neogenesis.

Prior surgery determines islet yield and insulin requirement in patients with chronic pancreatitis

BACKGROUND

Total pancreatectomy with islet autotransplantation (TP-IAT) is safe and effective in the management of intractable pain associated with chronic pancreatitis (CP). Prevention of pancreatogenic diabetes after TP-IAT is related to islet yield from the diseased pancreas. The purpose of this study is to compare islet yield and insulin requirement in the 76 patients who underwent different surgical procedures before TP-IAT at the Medical University of South Carolina between 2009 and 2011.

METHODS

Patients were grouped into four categories based on the operation they had before TP-IAT: transduodenal sphincteroplasty/no prior surgery (n=50), Whipple or Beger procedure (n=14), distal pancreatectomy (n=8), or lateral pancreaticojejunostomy (n=4). Islets were harvested from pancreases of those patients at our current good manufacturing practice facility. Total unpurified islets were transplanted into patients via portal vein infusion. Pancreatic fibrosis, islet yield, cell viability, and insulin requirement were measured.

RESULTS

The pancreases of transduodenal sphincteroplasty/no prior surgery and Whipple or Beger procedure patients were less fibrotic and had higher islet yield compared with those who had distal pancreatectomy or lateral pancreaticojejunostomy. Higher islet yield also correlated with a greater diabetes-free rate and a lesser insulin requirement at the following intervals: preoperative, postoperative, and 6 months after TP-IAT.

CONCLUSIONS

Prior surgery is strongly correlated with the extent of pancreatic fibrosis, islet yield, and insulin requirements in CP patients undergoing TP-IAT. The history of prior pancreatic resection and drainage procedures may be used to predict postoperative islet function and help to determine the optimal timing for TP-IAT in CP patients.

A Review of Autologous Islet Transplantation

Autologous islet transplantation after total or semitotal pancreatectomy aims to preserve insulin secretory function and prevent the onset of diabetes. The major indication for pancreatectomy is chronic pancreatitis with severe abdominal pain, a benign pancreatic tumor, and trauma. The metabolic outcome of autologous islet transplantation is better than that of allogeneic transplantation and depends on the number of transplanted islets. Achieving islet isolation from a fibrous or damaged pancreas is one of the biggest challenges of autologous islet transplantation; a major complication is portal vein thrombosis after crude islet infusion. However, the incidence of portal vein thrombosis has decreased as islet preparation techniques have improved over time.

A new enzyme mixture to increase the yield and transplant rate of autologous and allogeneic human islet products

BACKGROUND

The optimal enzyme blend that maximizes human islet yield for transplantation remains to be determined. In this study, we evaluated eight different enzyme combinations (ECs) in an attempt to improve islet yield. The ECs consisted of purified, intact or truncated class 1 (C1) and class 2 (C2) collagenases from Clostridium histolyticum (Ch), and neutral protease (NP) from Bacillus thermoproteolyticus rokko (thermolysin) or Ch (ChNP).

METHODS

We report the results of 249 human islet isolations, including 99 deceased donors (research n=57, clinical n=42) and 150 chronic pancreatitis pancreases. We prepared a new enzyme mixture (NEM) composed of intact C1 and C2 collagenases and ChNP in place of thermolysin. The NEM was first tested in split pancreas (n=5) experiments and then used for islet autologous (n=21) and allogeneic transplantation (n=10). Islet isolation outcomes from eight different ECs were statistically compared using multivariate analysis.

RESULTS

The NEM consistently achieved higher islet yields from pancreatitis (P<0.003) and deceased donor pancreases (P<0.001) than other standard ECs. Using the NEM, islet products met release criteria for transplantation from 8 of 10 consecutive pancreases, averaging 6510 ± 2150 islet equivalent number/gram (IEQ/g) pancreas and 694,681 ± 147,356 total IEQ/transplantation. In autologous isolation, the NEM yielded more than 200,000 IEQ from 19 of 21 pancreases (averaging 422,893 ± 181,329 total IEQ and 5979 ± 1469 IEQ/kg recipient body weight) regardless of the severity of fibrosis.

CONCLUSIONS

A NEM composed of ChNP with CIzyme high intact C1 collagenase recovers higher islet yield from deceased and pancreatitis pancreases while retaining islet quality and function.

A comparison of islet autotransplantation with allotransplantation and factors elevating acute portal pressure in clinical islet transplantation

BACKGROUND

Acute portal pressure rise is occasionally observed during intraportal islet infusion, especially in islet autotransplantation (IAT) where tissue purification is rarely applied. In this paper we investigate factors associated with acute portal pressure rise, a known risk factor for portal vein thrombosis.

METHODS

Retrospective data was collected on 15 islet autotransplant and 122 allogeneic islet transplant subjects. Non-purified pancreatic cells were transplanted in islet autotransplants, and purified islet cells were transplanted in allogeneic transplants. Portal pressure was documented throughout the islet infusion.

RESULTS

The total numbers of transplanted islets were significantly smaller in autotransplants than allografts, although the packed cell volume in autotransplants was larger. Autoislet infusion, with a larger packed cell volume, caused higher transient portal venous pressures than allogeneic islet transplant. Univariate analysis and multivariate linear regression revealed that packed cell volume and the number of transplanted cells were significant risk factors for acute portal pressure rise in both autotransplants and allogeneic transplants.

CONCLUSIONS

Non-purified IAT has a higher risk for acute portal pressure rise than allogeneic islet transplantation, and the rise is associated with the packed cell volume and the number of transplanted cells. Minimization of packed cell volume and cautious monitoring of portal pressure are important to avoid potential complications of portal hypertension.

Robot-assisted pancreatoduodenectomy with preservation of the vascular supply for autologous islet cell isolation and transplantation: a case report

Introduction

For patients with chronic pancreatitis presenting with medically intractable abdominal pain, surgical intervention may be the only treatment option. However, extensive pancreatic resections are typically performed open and are associated with a substantial amount of postoperative pain, wound complications and long recovery time. Minimally invasive surgery offers an avenue to improve results; however, current limitations of laparoscopic surgery render its application in the setting of chronic pancreatitis technically demanding. Additionally, pancreatic resections are associated with a high incidence of diabetes. Transplantation of islets isolated from the resected pancreas portion offers a way to prevent post-surgical diabetes; however, preservation of the vascular supply during pancreatic resection, which determines islet cell viability, is technically difficult using current laparoscopic approaches. With recent advances in the surgical field, robotic surgery now provides a means to overcome these obstacles to achieve the end goals of pain relief and preserved endocrine function. We present the first report of a novel, minimally invasive robotic approach for resection of the pancreatic head that preserves vascular supply and enables the isolation of a high yield of viable islets for transplantation.

Case presentation

A 35-year old Caucasian woman presented with intractable chronic abdominal pain secondary to chronic pancreatitis, with a stricture of her main pancreatic duct at the level of the ampulla of Vater and distal dilatation. She was offered a robotic-assisted pylorus-preserving pancreatoduodenectomy and subsequent islet transplantation, to both provide pain relief and preserve insulin-secretory reserves.

Conclusion

We present a novel, minimally invasive robotic approach for resection of the pancreatic head with complete preservation of the vascular supply, minimal warm ischemia time (less than three minutes) and excellent islet recovery (134,727 islet equivalent). Our patient is currently pain-free with normal glycemic control. Robot-assisted pylorus-preserving pancreatoduodenectomy and autologous islet transplantation can be safely performed and has the potential to minimize operative traumas as well as to partially preserve endocrine function. Results from this case report suggest that this dual procedure should be considered as a treatment option for patients with chronic pancreatitis at earlier stages of the disease, before irreversible islet loss occurs.

The effects of digestion enzymes on islet viability and cellular composition

The choice of enzyme blend is critical for successful islet isolation. Islet yield, viability, integrity, and function are important factors that influence the outcome of islet transplantation. Liberase HI has been used as a standard enzyme for pancreas digestion and has successfully produced islets that reversed diabetes. However, the replacement of Liberase HI with collagenase NB1 has significantly influenced the process outcome, both in quality and quantity of the isolated islets. The assessment of islet cells by Flow Cytometry (FC) has been reported to be useful for evaluating islet quality. The aim of this study was to assess the isolation outcomes and islet quality when comparing human islet cell processed with Liberase HI and NB1. A total of 66 islet isolations, 46 processed using Liberase HI and 20 using Serva NB1, were retrospectively analyzed. Islet yield, function in vitro, islet cell viability by FC, as well as isolation-related factors were compared. There was no significant difference in donor characteristics such as age and height; however, body mass index (BMI) in the Liberase HI group was significantly higher. There was also no significant difference in prepurification, postisolation, or postculture IEQ or percent recovery between the two groups. Flow data showed Liberase HI preparations had a significantly higher percent of live cells (DAPI(-)) and NG(+)/TMRE(+) when compared to NB1. Stimulation Indices (SI) for Liberase HI (n = 45) showed 3.17 and NB1 (n = 18) 2.71 (p = NS). The results of Annexin V/DAPI staining for live, apoptotic, and necrotic cells were 50.7 ± 2.24%, 14.4 ± 1.02%, and 27.8 ± 1.92% for Liberase HI versus 48.1 ± 1.93%, 12.3 ± 0.92%, and 33.9 ± 2.28% for NB1. Islets isolated using Liberase HI showed higher viable β cells by NG/TMRE staining and decreased necrosis by Annexin V/DAPI staining. FC assessment may be useful for determining the choice of digestion enzyme to maximize viable islets.

Autologous islet cell transplantation to prevent surgical diabetes

Autologous islet transplantation (AIT) is performed to prevent surgical diabetes after total or semi-total pancreatectomy for the treatment of chronic pancreatitis with severe abdominal pain. In addition, AIT is used in cases of benign pancreatic tumors and pancreatic trauma. It has been shown that AIT results in better outcomes in terms of glycemic control compared with allogeneic islet transplantation. The reasons for the favorable outcomes of AIT are thought to be: (i) patients have no autoimmune diseases; (ii) the transplanted islets do not suffer allogeneic rejection; (iii) diabetogenic antirejection drugs are not required; (iv) pancreata do not undergo a cytokine storm as a result of periods of brain death; (v) the period of cold preservation of retrieved pancreata is short; (vi) the isolated islets are immediately transplanted without culture; and (vii) pancreata with pancreatitis may contain more progenitor cells. Further research into AIT would help improve the results of allogeneic islet transplantation. Conversely, the technical difficulties associated with islet isolation appear to be the largest hurdle for AIT; therefore, remote center islet isolation may prove to be key in the promotion of this treatment.

Remote processing of pancreas can restore normal glucose homeostasis in autologous islet transplantation after traumatic whipple pancreatectomy: technical considerations

An emergency autologous islet transplant after a traumatic Whipple operation and subsequent total pancreatectomy was performed for a 21-year-old patient who was wounded with multiple abdominal gunshot wounds. After Whipple pancreatectomy, the remnant pancreas (63.5 g), along with other damaged organs, was removed by the surgeons at Walter Reed Army Medical Center (WRAMC) and shipped to Diabetes Research Institute (DRI) for islet isolation. The pancreas was preserved in UW solution for 9.25 h prior to islet isolation. Upon arrival, the organ was visually inspected; the pancreatic head was missing, the rest of the pancreas was damaged and full of blood; the tail looked normal. A 16-gauge catheter was inserted into the main duct and directed towards tail of the pancreas after the dissection of main duct in the midbody of the pancreas. The pancreas was distended with collagenase solution (Roche MTF) through the catheter. During 10 min of intraductal delivery of enzyme, the gland was distended uniformly. No leakage of the solution was observed. The pancreas was transferred to a Ricordi chamber for automated mechanical and enzymatic digestion. Islets were purified using a COBE 2991 cell processor. Islet equivalents (IEQ; 221,250) of 40% purity and 90% viability were recovered during the isolation, which were shipped back to WRAMC and infused by intraportal injection into the patient. Immediate islet function was demonstrated by the rapid elevation of serum C peptide followed by insulin independence with near normal oral glucose tolerance test (OGTT) 1 and 2 months later. It is possible to restore near normal glucose tolerance with autologous islet transplantation after total pancreatectomy even with suboptimal number of islets while confirming that islets processed at a remote site are suitable for transplantation.

Evaluation of viable β-cell mass is useful for selecting collagenase for human islet isolation: comparison of collagenase NB1 and liberase HI

The selection of enzyme blend is critical for the success of human islet isolations. Liberase HI collagenase (Roche) was introduced in the 1990s and had been widely used for clinical islet transplantation. More recently, a blend collagenase NB1 has been rendered available. The aim of this study was to evaluate the isolation outcomes and islet quality comparing human islet cells processed using NB1 and Liberase HI. A total of 90 isolations processed using NB1 (n = 40) or Liberase HI (n = 50) was retrospectively analyzed. Islet yield, function in vitro and in vivo, cellular (including β-cell-specific) viability and content, as well as isolation-related factors were compared. No significant differences in donor-related factors were found between the groups. There were also no significant differences in islet yields (NB1 vs. Liberase: 263,389 ± 21,550 vs. 324,256 ± 27,192 IEQ; p = n.s., respectively). The pancreata processed with NB1 showed a significantly longer digestion time (18.6 ± 0.7 vs. 14.5 ± 0.5 min, p < 0.01), lower β-cell viability (54.3 ± 3.4% vs. 72.0 ± 2.1%, p < 0.01), β-cell mass (93,671 ± 11,150 vs. 148,961 ± 12,812 IEQ, p < 0.01), and viable β-cell mass (47,317 ± 6,486 vs. 106,631 ± 10,228 VβIEQ, p < 0.01) than Liberase HI. In addition, islets obtained with Liberase showed significantly better graft function in in vivo assessment of islet potency. The utilization of collagenase NB1 in human islet isolation was associated with significantly lower β-cell viability, mass, and islet potency in vivo in our series when compared to Liberase HI, even though there was no significant difference in islet yields between the groups. Evaluation of viable β-cell mass contained in human islet preparations will be useful for selecting enzyme blends.

Quality of life improves for pediatric patients after total pancreatectomy and islet autotransplant for chronic pancreatitis

BACKGROUND & AIMS

Total pancreatectomy (TP) and islet autotransplant (IAT) have been used to treat patients with painful chronic pancreatitis. Initial studies indicated that most patients experienced significant pain relief, but there were few validated measures of quality of life. We investigated whether health-related quality of life improved among pediatric patients undergoing TP/IAT.

METHODS

Nineteen consecutive children (aged 5-18 years) undergoing TP/IAT from December 2006 to December 2009 at the University of Minnesota completed the Medical Outcomes Study 36-item Short Form (SF-36) health questionnaire before and after surgery. Insulin requirements were recorded.

RESULTS

Before TP/IAT, patients had below average health-related quality of life, based on data from the Medical Outcomes Study SF-36; they had a mean physical component summary (PCS) score of 30 and mental component summary (MCS) score of 34 (2 and 1.5 standard deviations, respectively, below the mean for the US population). By 1 year after surgery, PCS and MCS scores improved to 50 and 46, respectively (global effect, PCS P < .001, MCS P = .06). Mean scores improved for all 8 component subscales. More than 60% of IAT recipients were insulin independent or required minimal insulin. Patients with prior surgical drainage procedures (Puestow) had lower yields of islets (P = .01) and greater incidence of insulin dependence (P = .04).

CONCLUSIONS

Quality of life (physical and emotional components) significantly improve after TP/IAT in subsets of pediatric patients with severe chronic pancreatitis. Minimal or no insulin was required for most patients, although islet yield was reduced in patients with previous surgical drainage operations.

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.

Similar islet function in islet allotransplant and autotransplant recipients, despite lower islet mass in autotransplants

BACKGROUND

Despite high initial rates of insulin independence after islet allotransplant for type 1 diabetes, long-term islet function is suboptimal. Possible contributing factors include autoimmune recurrence, alloimmune rejection, or immunosuppressant medication toxicity. In contrast, islet autografts, infused at the time of pancreatectomy for chronic pancreatitis, are not subject to these variables. Islet function was compared in autograft and allograft recipients.

METHODS

Eight autograft and eight allograft recipients, insulin independent or requiring minimal insulin, were matched for similar duration posttransplant (mean 2.1±1.2 years). Eleven healthy control subjects were also enrolled. Subjects underwent oral and intravenous glucose tolerance testing and arginine stimulation testing.

RESULTS

Age, gender, body mass index, duration posttransplant, and hemoglobin A1c levels were similar between groups. Glucose tolerance was worse in transplant recipients compared with controls. Alloislet recipients received significantly more islet equivalents per kg body weight (IE/kg) than autograft recipients (9958±6229 IE/kg vs. 4589±1232 IE/kg, P=0.03). However, the glycemic response to oral glucose tolerance testing, the acute insulin response to glucose, and the acute insulin response to arginine did not differ significantly between islet allograft and autograft recipients.

CONCLUSIONS

Insulin secretion and glucose excursion were similar in allograft and autograft recipients, despite the latter group receiving less than half as many islets. Better preservation of islet mass in the autograft setting is likely related to the lack of autoimmunity, alloimmunity, and immunosuppressive drug toxicity, highlighting the potential for better outcomes in islet allotransplant for type 1 diabetes mellitus with refinements in immunosuppression.

Assessment of human islet isolation with four different collagenases

BACKGROUND

The isolation of islets from the human pancreas critically depends on the efficiency of the digestive enzymes. Liberase HI had been used as a standard preparation until the issues concerning bovine spongiform encephalopathy. Thus, we must now use other collagenases for clinical islet transplantation, four of which we have evaluated herein.

METHODS

The digestion of each of 17 pancreata from brain-dead donors was performed using the following collagenases: Liberase HI (HI; Roche, n = 9); Liberase MTF C/T (MTF; Roche, n = 4); Collagenase NB1 Premium Grade (NB1; Serva, n = 7); or Clzyme Collagenase HA (CI, VitaCyte, n = 4). Islet isolations were based on the Edmonton protocol for HI, whereas our modified islet isolation method was used for the three new enzymes (MTF, NB1, and CI).

RESULTS

There were no significant differences in donor age, body mass index, pancreas size, and cold ischemic time among the four groups. The phase I time in the NB1 group was significantly shorter than in the CI group (P = .0014). The prepurification IEQ/g in the HI group was significantly lower than the others (P = .0003 vs MTF, .0007 vs NB1, and .0009 vs CI, respectively). The postpurification IEQ/g in the MTF group was significantly higher than in the HI group (P = .006). The viability in the NB1 group was significantly greater than the HI group (P = .003).

CONCLUSION

Three new enzymes (MTF, NB1, and CI) may enable us to obtain higher islet yields than with HI.

Experience of islet isolation without neutral protease supplementation

BACKGROUND

We have reported improved islet isolation outcomes using a new digestion protocol where the pancreas is perfused only with collagenase, and neutral protease (NP) is administered during the digestion phase. Since the inception of this protocol, we have had some cases where administration of NP was not required. Our new protocol was utilized in 94 islet isolations. The timing of adding NP was dependent on the progression of digestion but in 10 cases the progression was rapid and most islets in the assessment samples were free from the exocrine tissue. As a result NP was not added at all for these isolations (no-NP group). In the remaining 84 isolations, NP was added during digestion phase (control group).

RESULTS

Pancreata in the each group were digested with a similar collagenase dose. Digestion time was shorter in the no-NP (15.0±1.8 vs 19.5±0.6 min, P=0.004). At post-digestion, the no-NP had fewer trapped islets (10.9±2.8 vs 28.1±2.4%, P=0.009). Post-purification islet yield was similar (355±45 x10 ( 3) vs 318±17 x10 ( 3) IE, P=0.29). Five preparations in the no-NP were used for clinical transplantation, leading to a 64.3±15.2% reduction in insulin usage. Interestingly, cold ischemia time was longer in the no-NP (10.3±0.9 vs 7.9±0.4 h, P=0.04). One particular collagenase lot having the highest NP activity contamination was used in 7 isolations in the no-NP. Our experience indicates that supplementation of collagenase with NP is not always necessary for effective isolation. Cold ischemia time and NP contamination should be evaluated for optimal NP dosage.

Predicting islet yield in pediatric patients undergoing pancreatectomy and autoislet transplantation for chronic pancreatitis

BACKGROUND/OBJECTIVE

Chronic pancreatitis (CP) in children is associated with significant morbidity and can lead to narcotic dependence. Total pancreatectomy (TP) may be indicated in refractory CP to relieve pain; simultaneous islet autotransplant (IAT) may prevent postsurgical diabetes. About half of pediatric patients are insulin independent 1 yr after IAT. Insulin independence correlates best with the number of islets available for transplantation (islet yield). Currently there is no known method to predict islet yield in a given patient. We assessed the ability of preoperative metabolic tests to predict islet yields in 10 children undergoing TP/IAT.

DESIGN/METHODS

Hemoglobin A1c (HbA(1c)) and mixed meal tolerance tests (MMTT) were obtained prior to surgery in 10 patients age <or= 18 yr. Fasting glucose, C-peptide, and creatinine were used to calculate the C-peptide to glucose* creatinine ratio (CPGCR). C-peptide peak and area under the curve (AUC) were determined from 2 h MMTT. Linear regressions were performed to predict islet yield from baseline test results.

RESULTS

Islet yield ranged from 7000 to 434 000 islet equivalents (IE) (mean 222 452 +/- 148 697 IE). Islet yield was well predicted from body weight and fasting plasma glucose (R (2) = 57%, adjusted for overfitting by bootstrap). Islet yield was positively associated with CPGCR, peak C-peptide, and AUC C-peptide and negatively associated with HbA(1c).

CONCLUSIONS

Pilot data from 10 pediatric patients suggest that simple preoperative measurement of fasting plasma glucose may give a useful prediction of islet yield. Islet yield correlates with HbA(1c) and C-peptide levels. This information allows individual candidates to weigh the specific risk of becoming diabetic against the benefit of pain relief should they undergo TP-IAT.