title: High-mobility group box 1 expressions in hypoxia-induced damaged mouse islets.
abstract: BACKGROUND
  Discovering a new, accurate, and useful damage marker for isolated islets is critical for avoiding the transplantation of nontherapeutic preparations. Recently, we have reported that islets that contained uniquely high levels of high-mobility group box 1 (HMGB1) protein and cytokine induced damaged islets released HMGB1 in a mouse model. Islets are frequently exposed to hypoxic conditions during organ procurement, organ transportation, islet isolation, and islet storage before transplantation. In the present study, we analyzed HMGB1 expressions in hypoxia-induced damaged mouse islets.
  
  
  METHODS
  Damaged mouse islets were generated by hypoxic conditions (1% O2, 5% CO(2), and 94% N(2)). HMGB1 expressions and production levels were assessed by quantitative real-time polymerase chain reaction (PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA) studies. In vivo islet function was analyzed using transplantation assay using streptozotocin-induced diabetic mice.
  
  
  RESULTS
  HMGB1 was mainly stained in the nucleus in the intact islets; however, HMGB1 was present in not only the nucleus, but also the cytoplasm in hypoxia-induced damaged islets. HMGB1 messenger RNA (mRNA) levels were up-regulated in the hypoxia-induced damaged islets, suggesting that HMGB1 was intentionally generated during hypoxia. HMGB1 protein levels in the islets were gradually decreased with time under hypoxic conditions. The amount of released HMGB1 levels and the amount of released HMGB1 levels per hour were significantly increased in damaged (noncurable) islets.
  
  
  CONCLUSIONS
  When islets were damaged by hypoxic condition, HMGB1 was synthesized and released from hypoxia-induced damaged islets. The amount of released HMGB1 and/or the amount of released HMGB1 per hour might be a useful marker for detecting damaged islets and might be used for islet potency assay.
authors.affiliation: Baylor Research Institute, Islet Cell Laboratory, Dallas, Texas, USA.
authors.forename: T
authors.initials: T
authors.lastname: Itoh
authors.forename: S
authors.initials: S
authors.lastname: Iwahashi
authors.forename: M
authors.initials: M
authors.lastname: Shimoda
authors.forename: D
authors.initials: D
authors.lastname: Chujo
authors.forename: M
authors.initials: M
authors.lastname: Takita
authors.forename: J A
authors.initials: JA
authors.lastname: SoRelle
authors.forename: B
authors.initials: B
authors.lastname: Naziruddin
authors.forename: M F
authors.initials: MF
authors.lastname: Levy
authors.forename: S
authors.initials: S
authors.lastname: Matsumoto
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005786:Gene Expression Regulation; D024243:HMGB1 Protein / Q000096:biosynthesis*; D000860:Hypoxia / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D007515:Islets of Langerhans / Q000378:metabolism*; D016381:Islets of Langerhans Transplantation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010100:Oxygen / Q000378:metabolism
chemical_list: D024243:HMGB1 Protein; D010100:Oxygen