title: Islet isolation from adult designated pathogen-free pigs: use of the newer bovine nervous tissue-free enzymes and a revised donor selection strategy would improve the islet graft function.
abstract: BACKGROUND
  In clinical trials using adult porcine islet products, islets should be isolated from the designated pathogen-free (DPF) pigs under the current good manufacturing practice (GMP) regulations. Our previous studies suggested that male DPF pigs are better donors than retired breeder pigs and histomorphometrical parameters of donor pancreas predict the porcine islet quality. We aimed to investigate whether the use of the newer bovine nervous tissue-free enzymes and a revised donor selection strategy could improve the islet graft function in the context of islet isolation with DPF pigs.
  
  
  METHODS
  Using 30 DPF pigs within a closed herd, we compared the islet yield of porcine islets isolated with Liberase PI (n = 11, as a historical control group), Liberase MTF C/T, which is a GMP-grade enzyme (n = 12), and CIzyme collagenase MA/BP protease (n = 7). We analyzed the relationship between the diabetes reversal rate of recipient NOD/SCID mice (n = 75) and histomorphometric parameters of each donor pancreas as well as donor characteristics.
  
  
  RESULTS
  Proportion of islets larger than 200 μm from the biopsied donor pancreas (P = 0.006) better predicted islet yield than age (P = 0.760) or body weight (P = 0.371) of donor. The proportion of islets larger than 200 μm from the biopsied donor pancreas was not related to the sex of the donor miniature pig (P = 0.358). The islet yield obtained with the three enzymes did not differ, even after stratification of the donor with the histomorphometric parameters of the biopsied donor pancreas and the sex of donor. The use of the newer bovine nervous tissue-free enzymes (P < 0.001), a higher proportion of large islets in donor pancreas (P = 0.006), and a male sex of the donor (P = 0.025) were independent predictors of earlier diabetes reversal.
  
  
  CONCLUSIONS
  Use of the newer bovine nervous tissue-free enzymes including a GMP-grade enzyme resulted in better islet quality than that of islet isolated using Liberase PI. To obtain high-quality islet from DPF pigs, the donor should be male pig and histomorphometrical parameters from donor pancreas should be considered.
authors.affiliation: Xenotransplantation Research Center, Seoul National University Hospital, Seoul, Korea.
authors.forename: Sang-Man
authors.initials: SM
authors.lastname: Jin
authors.forename: Jun Seop
authors.initials: JS
authors.lastname: Shin
authors.forename: Kang Seok
authors.initials: KS
authors.lastname: Kim
authors.forename: Chang-Hoon
authors.initials: CH
authors.lastname: Gong
authors.forename: Su Kyoung
authors.initials: SK
authors.lastname: Park
authors.forename: Jung-Sik
authors.initials: JS
authors.lastname: Kim
authors.forename: Su-Cheong
authors.initials: SC
authors.lastname: Yeom
authors.forename: Eung Soo
authors.initials: ES
authors.lastname: Hwang
authors.forename: Choon Taek
authors.initials: CT
authors.lastname: Lee
authors.forename: Sang-Joon
authors.initials: SJ
authors.lastname: Kim
authors.forename: Chung-Gyu
authors.initials: CG
authors.lastname: Park
mesh_terms: D000818:Animals; D002417:Cattle; D002469:Cell Separation / Q000379:methods*; D017364:Collagenases / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000601:surgery; D046148:Donor Selection; D005260:Female; D007515:Islets of Langerhans / Q000502:physiology* / Q000601:surgery* / Q000648:ultrastructure*; D016381:Islets of Langerhans Transplantation / Q000379:methods*; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D013552:Swine; D013556:Swine, Miniature; D013820:Thermolysin / Q000378:metabolism; D014183:Transplantation, Heterologous / Q000502:physiology
chemical_list: D017364:Collagenases; C106635:Liberase; D013820:Thermolysin