title: Evaluation of viable β-cell mass is useful for selecting collagenase for human islet isolation: comparison of collagenase NB1 and liberase HI.
abstract: 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.
authors.affiliation: Cell Transplant Center, Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL, USA.
authors.forename: R
authors.initials: R
authors.lastname: Misawa
authors.forename: C
authors.initials: C
authors.lastname: Ricordi
authors.forename: A
authors.initials: A
authors.lastname: Miki
authors.forename: S
authors.initials: S
authors.lastname: Barker
authors.forename: R D
authors.initials: RD
authors.lastname: Molano
authors.forename: A
authors.initials: A
authors.lastname: Khan
authors.forename: S
authors.initials: S
authors.lastname: Miyagawa
authors.forename: L
authors.initials: L
authors.lastname: Inverardi
authors.forename: R
authors.initials: R
authors.lastname: Alejandro
authors.forename: A
authors.initials: A
authors.lastname: Pileggi
authors.forename: H
authors.initials: H
authors.lastname: Ichii
mesh_terms: D000328:Adult; D002469:Cell Separation; D002470:Cell Survival; D017364:Collagenases / Q000378:metabolism*; D005260:Female; D006801:Humans; D050417:Insulin-Secreting Cells / Q000166:cytology* / Q000502:physiology / Q000637:transplantation*; D016381:Islets of Langerhans Transplantation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013820:Thermolysin / Q000378:metabolism*
chemical_list: D017364:Collagenases; C106635:Liberase; D013820:Thermolysin