Oxygenated Thawing and Rewarming Alleviate Rewarming Injury of Cryopreserved Pancreatic Islets

Biochem Biophys Res Commun. 2017 May 6;486(3):817-823. doi: 10.1016/j.bbrc.2017.03.134. Epub 2017 Mar 27.

Abstract

Background/aims: 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.

Methods: 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.

Results: 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.

Conclusion: Oxygenated thawing/rewarming alleviated islet volume loss, with the help of oxygenated culture.

Keywords: Cryopreservation; Oxygenation; Pancreatic islet; Rewarming injury.

MeSH terms

  • Cell Survival / drug effects
  • Cryopreservation / methods*
  • Cryoprotective Agents / pharmacology
  • Glucose / pharmacology
  • Humans
  • Insulin / metabolism
  • Insulin Secretion
  • Islets of Langerhans / cytology
  • Islets of Langerhans / drug effects*
  • Islets of Langerhans / metabolism
  • Islets of Langerhans Transplantation
  • Oxygen / pharmacology*
  • Primary Cell Culture
  • Rewarming / methods

Substances

  • Cryoprotective Agents
  • Insulin
  • Glucose
  • Oxygen