title: Oxygenated thawing and rewarming alleviate rewarming injury of cryopreserved pancreatic islets.
abstract: Pancreatic islet transplantation is an effective treatment for Type 1 diabetic patients to eliminate insulin injections; however, a shortage of donor organs hinders the widespread use. Although long-term islet storage, such as cryopreservation, is considered one of the key solutions, transplantation of cryopreserved islets is still not practical due to the extensive loss during the cryopreservation-rewarming process. We have previously reported that culturing islets in a hyperoxic environment is an effective treatment to prevent islet death from the hypoxic injury during culture. In this study, we explored the effectiveness of thawing and rewarming cryopreserved islets in a hyperoxic environment.
  
  
  
  Following cryopreservation of isolated human islets, the thawing solution and culture media were prepared with or without pre-equilibration to 50% oxygen. Thawing/rewarming and the pursuant two-day culture were performed with or without oxygenation. Short-term recovery rate, defined as the volume change during cryopreservation and thawing/rewarming, was assessed. Ischemia-associated and inflammation-associated gene expressions were examined using qPCR after the initial rewarming period. Long-term recovery rate, defined as the volume change during the two-day culture after the thawing/rewarming, was also examined. Islet metabolism and function were assessed by basal oxygen consumption rate and glucose stimulated insulin secretion after long-term recovery.
  
  
  
  Oxygenated thawing/rewarming did not alter the short-term recovery rate. Inflammation-associated gene expressions were elevated by the conventional thawing/rewarming method and suppressed by the oxygenated thawing/rewarming, whereas ischemia-associated gene expressions did not change between the thawing/rewarming methods. Long-term recovery rate experiments revealed that only the combination therapy of oxygenated thawing/rewarming and oxygenated culture alleviated islet volume loss. These islets showed higher metabolism and better function among the conditions examined.
  
  
  
  Oxygenated thawing/rewarming alleviated islet volume loss, with the help of oxygenated culture.
authors.affiliation: Division of Developmental and Translational Diabetes and Endocrinology Research, Department of Diabetes and Metabolic Researches, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA 91010, USA. Electronic address: hkomatsu@coh.org.
authors.forename: Hirotake
authors.initials: H
authors.lastname: Komatsu
authors.affiliation: Division of Developmental and Translational Diabetes and Endocrinology Research, Department of Diabetes and Metabolic Researches, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA 91010, USA.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Barriga
authors.affiliation: Division of Developmental and Translational Diabetes and Endocrinology Research, Department of Diabetes and Metabolic Researches, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA 91010, USA.
authors.forename: Leonard
authors.initials: L
authors.lastname: Medrano
authors.affiliation: Division of Developmental and Translational Diabetes and Endocrinology Research, Department of Diabetes and Metabolic Researches, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA 91010, USA.
authors.forename: Keiko
authors.initials: K
authors.lastname: Omori
authors.affiliation: Division of Developmental and Translational Diabetes and Endocrinology Research, Department of Diabetes and Metabolic Researches, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA 91010, USA.
authors.forename: Fouad
authors.initials: F
authors.lastname: Kandeel
authors.affiliation: Division of Developmental and Translational Diabetes and Endocrinology Research, Department of Diabetes and Metabolic Researches, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA 91010, USA.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Mullen
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D016381:Islets of Langerhans Transplantation; D010100:Oxygen / Q000494:pharmacology*; D061251:Primary Cell Culture; D017694:Rewarming / Q000379:methods
chemical_list: D003451:Cryoprotective Agents; D007328:Insulin; D005947:Glucose; D010100:Oxygen
keywords: Cryopreservation; Oxygenation; Pancreatic islet; Rewarming injury