title: Improved outcomes in islet isolation and transplantation by the use of a novel hemoglobin-based O2 carrier.
abstract: During isolation, islets are exposed to warm ischemia. In this study, intraductal administration of oxygenated polymerized, stroma-free hemoglobin-pyridoxalated (Poly SFH-P) was performed to improve O2 delivery. Rat pancreata subjected to 30-min warm ischemia were perfused intraductally with collagenase in oxygenated Poly SFH-P/RPMI or RPMI (control). PO2 was increased by Poly SFH-P (381.7 +/- 35.3 mmHg vs. 202.3 +/- 28.2, p = 0.01) and pH maintained within physiological range (7.4-7.2 vs. 7.1-6.6, p = 0.009). Islet viability (77% +/- 4.6 vs. 63% +/- 4.7, p = 0.04) was improved and apoptosis lower with Poly SFH-P (caspase-3: 34,714 +/- 2167 vs. 45,985 +/- 1382, respectively, p = 0.01). Poly SFH-P improved islet responsiveness to glucose as determined by increased intracellular Ca2+ levels and improved insulin secretion (SI 5.4 +/- 0.1 vs. 3.1 +/- 0.2, p = 0.03). Mitochondrial integrity was improved in Poly SFH-P-treated islets, which showed higher percentage change in membrane potential after glucose stimulation (14.7% +/- 1.8 vs. 9.8 +/- 1.4, respectively, p < 0.05). O2 delivery by Poly SFH-P did not increase oxidative stress (GSH 7.1 +/- 2.9 nm/mg protein for Poly SFH-P vs. 6.8 +/- 2.4 control, p = 0.9) or oxidative injury (MDA 1.8 +/- 0.9 nmol/mg protein vs. 6.2 +/- 2.4, p = 0.19). Time to reach normoglycemia in transplanted diabetic nude mice was shorter (1.8 +/- 0.4 vs. 7 +/- 2.5 days, p = 0.02), and glucose tolerance improved in the Poly SFH-P group (AUC 8106 +/- 590 vs. 10,863 +/- 946, p = 0.03). Oxygenated Poly SFH-P improves islet isolation and transplantation outcomes by preserving mitochondrial integrity.
authors.affiliation: Division of Transplantation, University of Illinois at Chicago, Illinois, USA.
authors.forename: J G
authors.initials: JG
authors.lastname: Avila
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: B
authors.initials: B
authors.lastname: Barbaro
authors.forename: A
authors.initials: A
authors.lastname: Gangemi
authors.forename: M
authors.initials: M
authors.lastname: Qi
authors.forename: J
authors.initials: J
authors.lastname: Kuechle
authors.forename: N
authors.initials: N
authors.lastname: Doubleday
authors.forename: M
authors.initials: M
authors.lastname: Doubleday
authors.forename: T
authors.initials: T
authors.lastname: Churchill
authors.forename: P
authors.initials: P
authors.lastname: Salehi
authors.forename: J
authors.initials: J
authors.lastname: Shapiro
authors.forename: L H
authors.initials: LH
authors.lastname: Philipson
authors.forename: E
authors.initials: E
authors.lastname: Benedetti
authors.forename: J R T
authors.initials: JR
authors.lastname: Lakey
authors.forename: J
authors.initials: J
authors.lastname: Oberholzer
mesh_terms: D000818:Animals; D017209:Apoptosis; D001802:Blood Substitutes / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002469:Cell Separation / Q000379:methods; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D006454:Hemoglobins / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000166:cytology* / Q000187:drug effects; D016381:Islets of Langerhans Transplantation / Q000379:methods* / Q000502:physiology*; D008564:Membrane Potentials; D051379:Mice; D008819:Mice, Nude; D051336:Mitochondrial Membranes / Q000187:drug effects / Q000502:physiology; D018384:Oxidative Stress / Q000187:drug effects; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D014044:Tolbutamide / Q000494:pharmacology; D014183:Transplantation, Heterologous
chemical_list: D001802:Blood Substitutes; D006454:Hemoglobins; C030939:polyhemoglobin-pyridoxal-5-phosphate; D011732:Pyridoxal Phosphate; D014044:Tolbutamide; D005947:Glucose; D002118:Calcium