title: αB-crystallin improves murine cardiac function and attenuates apoptosis in human endothelial cells exposed to ischemia-reperfusion.
abstract: BACKGROUND
  This study investigates the protective effect of exogenous αB-crystallin (CryAB) on myocardial function after ischemia-reperfusion injury.
  
  
  METHODS
  Mice underwent temporary left anterior descending artery occlusion for 30 minutes. Either CryAB (50 μg) or phosphate-buffered saline (100 μL [n=6, each group]) were injected in the intramyocardial medial and lateral perinfarct zone 15 minutes before reperfusion. Intraperitoneal injections were administered every other day. Left ventricular ejection fraction was evaluated on postoperative day 40 with magnetic resonance imaging. To investigate the effect of CryAB on apoptosis after hypoxia/reoxygenation in vitro, murine atrial cardiomyocytes (HL-1 cells) or human microvascular endothelial cells (HMEC-1) were incubated with either 50 μg CryAB (500 μg /10 mL) or phosphate-buffered saline in a hypoxia chamber for 6, 12, and 24 hours, followed by 30 minutes of reoxygenation at room air. Apoptosis was then assessed by western blot (Bcl-2, free bax, cleaved caspases-3, 9, PARP) and enzyme-linked immunosorbent assay analyses (cytoplasmic histone-associated DNA fragments and caspase-3 activity).
  
  
  RESULTS
  On postoperative day 40, CryAB-treated mice had a 1.8-fold increase in left ventricular ejection fraction versus control mice (27%±6% versus 15%±4% SD, p<0.005). In vitro, (1) the HL-1 cells showed no significant difference in apoptotic protein expression, cytoplasmic histone-associated DNA fragments, or caspase-3 activity; (2) the HMEC-1 cells had increased but not significant apoptotic protein expression with, however, a significant decrease in cytoplasmic histone-associated DNA fragments (1.5-fold, p<0.01) and caspase-3 activity (2.7-fold, p<0.005).
  
  
  CONCLUSIONS
  Exogenous CryAB administration significantly improves cardiac function after ischemia-reperfusion injury, in vivo. The protective anti-apoptotic affects of CryAB may target the endothelial cell.
authors.affiliation: Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, California 94305, USA.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Velotta
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Kimura
authors.forename: Stephanie H
authors.initials: SH
authors.lastname: Chang
authors.forename: Jaehoon
authors.initials: J
authors.lastname: Chung
authors.forename: Satoshi
authors.initials: S
authors.lastname: Itoh
authors.forename: Jonathan
authors.initials: J
authors.lastname: Rothbard
authors.forename: Philip C
authors.initials: PC
authors.lastname: Yang
authors.forename: Lawrence
authors.initials: L
authors.lastname: Steinman
authors.forename: Robert C
authors.initials: RC
authors.lastname: Robbins
authors.forename: Michael P
authors.initials: MP
authors.lastname: Fischbein
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D042783:Endothelial Cells / Q000187:drug effects*; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000502:physiology; D016277:Ventricular Function, Left / Q000187:drug effects*; D038203:alpha-Crystallin B Chain / Q000494:pharmacology*
chemical_list: D038203:alpha-Crystallin B Chain