title: 2-APB protects against liver ischemia-reperfusion injury by reducing cellular and mitochondrial calcium uptake.
abstract: Ischemia-reperfusion (I/R) injury is a commonly encountered clinical problem in liver surgery and transplantation. The pathogenesis of I/R injury is multifactorial, but mitochondrial Ca(2+) overload plays a central role. We have previously defined a novel pathway for mitochondrial Ca(2+) handling and now further characterize this pathway and investigate a novel Ca(2+)-channel inhibitor, 2-aminoethoxydiphenyl borate (2-APB), for preventing hepatic I/R injury. The effect of 2-APB on cellular and mitochondrial Ca(2+) uptake was evaluated in vitro by using (45)Ca(2+). Subsequently, 2-APB (2 mg/kg) or vehicle was injected into the portal vein of anesthetized rats either before or following 1 h of inflow occlusion to 70% of the liver. After 3 h of reperfusion, liver injury was assessed enzymatically and histologically. Hep G2 cells transfected with green fluorescent protein-tagged cytochrome c were used to evaluate mitochondrial permeability. 2-APB dose-dependently blocked Ca(2+) uptake in isolated liver mitochondria and reduced cellular Ca(2+) accumulation in Hep G2 cells. In vivo I/R increased liver enzymes 10-fold, and 2-APB prevented this when administered pre- or postischemia. 2-APB significantly reduced cellular damage determined by hematoxylin and eosin and terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling staining of liver tissue. In vitro I/R caused a dissociation between cytochrome c and mitochondria in Hep G2 cells that was prevented by administration of 2-APB. These data further establish the role of cellular Ca(2+) uptake and subsequent mitochondrial Ca(2+) overload in I/R injury and identify 2-APB as a novel pharmacological inhibitor of liver I/R injury even when administered following a prolonged ischemic insult.
authors.affiliation: Department of Surgery, Division of Hepatobiliary Surgery and Liver Transplantation, Suite 801 Oxford House, 1313 21st Avenue South, Vanderbilt University Medical Center, Nashville, TN 37232-4753, USA.
authors.forename: I B
authors.initials: IB
authors.lastname: Nicoud
authors.forename: C D
authors.initials: CD
authors.lastname: Knox
authors.forename: C M
authors.initials: CM
authors.lastname: Jones
authors.forename: C D
authors.initials: CD
authors.lastname: Anderson
authors.forename: J M
authors.initials: JM
authors.lastname: Pierce
authors.forename: A E
authors.initials: AE
authors.lastname: Belous
authors.forename: T M
authors.initials: TM
authors.lastname: Earl
authors.forename: R S
authors.initials: RS
authors.lastname: Chari
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001896:Boron Compounds / Q000494:pharmacology* / Q000627:therapeutic use; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology* / Q000627:therapeutic use; D002132:Calcium Radioisotopes; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008099:Liver / Q000098:blood supply / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000187:drug effects / Q000378:metabolism; D010539:Permeability; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015427:Reperfusion Injury / Q000201:enzymology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D013997:Time Factors; D014162:Transfection
chemical_list: D001896:Boron Compounds; D002121:Calcium Channel Blockers; D002132:Calcium Radioisotopes; D011993:Recombinant Fusion Proteins; D045304:Cytochromes c; C109986:2-aminoethoxydiphenyl borate; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D002118:Calcium