446 Intraductal delivery of alpha-1-antitrypsin increases the yield of autologous human islets for transplant
Tuesday November 17, 2015 from 11:00 to 12:30
Plenary Room 1

Joshua J Wilhelm, United States

Director, Islet Manufacturing and R&D

Surgery - Schulze Diabetes institute

University of Minnesota


Intraductal delivery of alpha-1-antitrypsin increases the yield of autologous human islets for transplant

Joshua Wilhelm1, David T Heller1, Melena D Bellin1,3, Thomas R Gilmore1, Greg J Beilman2, Ty B Dunn2, Timothy L Pruett2, K Louise Berry2, Bernhard J Hering1.

1Schulze Diabetes Institute, University of Minnesota, Minneapolis, MN, United States; 2Department of Surgery, University of Minnesota, Minneapolis, MN, United States; 3Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States

Background: Previous work has shown that ductal preservation (DP) alone or with a protease inhibitor (PI) can be beneficial for islet yield and function following pancreatic islet isolations.  The benefit of these approaches is especially evident when the quality of the pancreas is compromised, for example by long warm or cold ischemia time.  The use of alpha-1-antitrypsin (A1AT), a serine PI with other multimodal accessory functions (i.e., anti-inflammatory, anti-bacterial/viral, beta-cell specific benefits), in DP has also been reported recently.  We have previously shown that A1AT at 0.5 mg/ml in islet culture inhibits damage to deceased donor human islets from endogenous proteases, presumably also active in the native pancreas during progression of chronic pancreatitis.  As there is some evidence that A1AT may inhibit activity of tissue dissociation enzymes (TDEs), and warm/cold ischemia times are very short in total pancreatectomy and islet autotransplantation (TPIAT), the role of A1AT is unclear and has not yet been reported.  The substantial increase in human deceased donor and porcine islet yields previously observed by us and other groups with use of A1AT justified a small pilot study in this setting.

Methods: In 10 consecutive adult TPIAT cases, the main pancreatic duct was cannulated immediately following TP and preserved with 50 ml of modified UW preservation solution containing 0.5 mg/ml of A1AT (25ml in 1 case with ductal abnormality).  The pancreas was transported for islet isolation under otherwise standard conditions.  Demographics, islet isolation and quality control data were collected from all cases and compared to case-matched controls.  Matching was performed using an algorithm accounting for factors known to influence islet mass (i.e., PRSS1, surgeries like Whipple or Puestow, severity of fibrosis), as well as age and gender, and blinded to outcomes until the final match step.  A paired t-test was performed for all comparisons between cases.

Results: Demographics, including age, BMI, fibrosis severity, and pancreatitis duration did not differ between the 10 cases and matched controls. DP with A1AT resulted in an overall increase in islet yield at digest of 66.5% (4,961 ± 1,728 vs 2,977 ± 1,427 IEQ/gm pancreas; p=0.002) versus controls.  The greatest increase (169%) was seen in the subset of 4 cases with greatest disease severity (9 on a 10-pt scale).    Other isolation parameters were similar, except for a trend towards higher % embedded islets, quality score, size index, and pellet volume indicating possible inhibition of TDEs and preservation of exocrine tissue.  Quality control data was similar for both groups (FDA/PI and OCR/DNA).

Conclusions:  This is the first report of the use of DP with A1AT for islet isolation in TPIAT, and provides proof of principle that intervention to prevent endogenous protease activity is appropriate in this setting, preserving islet mass available after digest and for transplant, especially with severe fibrosis. Both pre- and post-transplant patient treatment could provide a further benefit, as is currently being explored in T1DM patients.  Optimization of the A1AT dose and the resulting effect on TDEs needs to be further explored to maximize the utility of this intervention in terms of islet yield and quality.  Based on the success of this pilot study, the intervention is continuing in all TPIAT cases at this time.  Early posttransplant metabolic data and additional cases will be reviewed at the congress.


[1] Loganathan, G., et al., Transplant Proc, 2010. 42(6): p. 2055-7.
[2] Shimoda, M., et al., Cell Transplant, 2012. 21(2-3): p. 465-71.
[3] Takita, M., et al., Pancreas, 2014. 43(8): p. 1249-55.

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