title: Profiling of cell stress protein expression in cardiac tissue of cardiosurgical patients undergoing remote ischemic preconditioning: implications for thioredoxin in cardioprotection.
abstract: BACKGROUND
  Transient episodes of ischemia in a remote organ (remote ischemic preconditioning, RIPC) can attenuate myocardial ischemia/reperfusion injury but the underlying mechanisms of RIPC in the target organ are still poorly understood. Recent animal studies suggested that the small redox protein thioredoxin may be a potential candidate for preconditioning-induced organprotection. Here we employed a human proteome profiler array to investigate the RIPC regulated expression of cell stress proteins and particularly of thioredoxin in heart tissue of cardiosurgical patients with cardiopulmonary bypass (CPB).
  
  
  METHODS
  RIPC was induced by four 5 minute cycles of transient upper limb ischemia/reperfusion using a blood pressure cuff. Right atrial tissue was obtained from patients receiving RIPC (N = 19) and control patients (N = 19) before and after CPB. Cell stress proteome profiler arrays as well as Westernblotting and ELISA experiments for thioredoxin (Thio-1) were performed employing the respective tissue samples.
  
  
  RESULTS
  Protein arrays revealed an up-regulation of 26.9% (7/26; CA IX, Cyt C, HSP-60, HSP-70, pJNK, SOD2, Thio-1) of cell stress associated proteins in RIPC tissue obtained before CPB, while 3.8% (1/26; SIRT2) of the proteins were down-regulated. Array results for thioredoxin were verified by semi-quantitative Westernblotting studies which showed a significant up-regulation of thioredoxin protein levels in cardiac tissue samples of RIPC patients taken before CPB (RIPC: 5.36 ± 0.85 a.u.; control: 3.23 ± 0.39 a.u.; P < 0.05). Quantification of thioredoxin levels in tissue of RIPC and control patients by ELISA experiments further confirmed the Westernblotting results (RIPC: 0.30 ± 0.02 ng/mg protein; control: 0.24 ± 0.02 ng/mg protein; P < 0.05).
  
  
  CONCLUSIONS
  We provide evidence for thioredoxin as a RIPC-induced factor in heart tissue of cardiosurgical patients and identified several cell stress associated proteins that are regulated by RIPC and may play a role in RIPC-mediated cardioprotection.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Schwanenweg 21, 24105, Kiel, Germany. karina.zitta@uksh.de.
authors.forename: Karina
authors.initials: K
authors.lastname: Zitta
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Schwanenweg 21, 24105, Kiel, Germany. Patrick.Meybohm@kgu.de.|Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt am Main, Germany. Patrick.Meybohm@kgu.de.
authors.forename: Patrick
authors.initials: P
authors.lastname: Meybohm
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Schwanenweg 21, 24105, Kiel, Germany. Matthias.Gruenewald@uksh.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Gruenewald
authors.affiliation: Department of Cardiovascular Surgery, University Hospital Schleswig-Holstein, Kiel, Germany. jochen.cremer@uksh-kiel.de.
authors.forename: Jochen
authors.initials: J
authors.lastname: Cremer
authors.affiliation: Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt am Main, Germany. kai.zacharowski@kgu.de.
authors.forename: Kai D
authors.initials: KD
authors.lastname: Zacharowski
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Schwanenweg 21, 24105, Kiel, Germany. Jens.Scholz@uksh.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Scholz
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Schwanenweg 21, 24105, Kiel, Germany. Markus.Steinfath@uksh.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Steinfath
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Schwanenweg 21, 24105, Kiel, Germany. martin.albrecht@uksh.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Albrecht
mesh_terms: D002316:Cardiotonic Agents / Q000378:metabolism*; D013504:Cardiovascular Surgical Procedures; D004797:Enzyme-Linked Immunosorbent Assay; D006360:Heat-Shock Proteins; D006801:Humans; D019194:Ischemic Preconditioning; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D040901:Proteomics; D013312:Stress, Physiological; D013879:Thioredoxins / Q000378:metabolism*
chemical_list: D002316:Cardiotonic Agents; D006360:Heat-Shock Proteins; C491203:TXN protein, human; D013879:Thioredoxins