title: Impact of ischemia-reperfusion on extracellular matrix processing and structure of the basement membrane of the heart.
abstract: OBJECTIVE
  Acute ischemic injury is a strong inductor of cardiac remodelling, resulting in structural changes of the extracellular matrix (ECM) and basement membrane (BM). In a large animal model of ischemia-reperfusion (I/R) we investigated the post-ischemic liberation of the collagen-IV-fragments Tumstatin (TUM; 28 kDa-fragment of collagen-IV-alpha-3), Arresten (ARR; 26 kDa-fragment of collagen-IV-alpha-1) and Endorepellin (LG3, 85 kDa-fragment of perlecan) which are biologically active in angiogenesis and vascularization in the post-ischemic myocardium.
  
  
  RESULTS
  In this blinded study, 30 pigs were randomized to 60 min of global I/R at either 4°C or 32°C or served as control. Three transmyocardial tissue samples were collected prior to ischemia and within 30 min and 150 min of reperfusion. Tissue content of TUM, ARR and LG3 was analyzed by western blotting and immunostaining. Within 150 min of mild hypothermic I/R a significantly increased tissue content of ARR (0.17±0.14 vs. 0.56±0.56; p = 0.001) and LG3 (1.13±0.34 vs. 2.51±1.71, p<0.001) was observed. In contrast, deep hypothermic I/R was not associated with a significant release of cleavage products. Cleavage of TUM remained unchanged irrespective of temperature. Increased matrix processing following mild hypothermia I/R is further supported by a >11fold elevation of creatine kinase (2075±2595 U/l vs. 23248±6551 U/l; p<0.001) in the coronary sinus plasma samples. Immunostaining demonstrated no changes for ARR and LG3 presentation irrespective of temperature. In contrast, TUM significantly decreased in the BM surrounding cardiomyocytes and capillaries after mild and deep hypothermic I/R, thus representing structural alterations of the BM in these groups.
  
  
  CONCLUSIONS
  The study demonstrates an early temperature-dependent processing of Col-IV as major component of the BM of cardiomyocytes and vascular endothelium. These observations support the protective effects of deep hypothermia during I/R. Furthermore, the results suggest an increased structural remodelling of the myocardial basement membrane with potential functional impairment during mild hypothermic I/R which may contribute to the progression to post-ischemic heart failure.
authors.affiliation: Department of Internal Medicine I (Cardiology, Angiology, Pneumology), Friedrich- Schiller University, Jena, Germany; Institute of Cardiovascular Research and Sports Medicine, German Sports University, Cologne, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Lauten
authors.affiliation: Institute of Cardiovascular Research and Sports Medicine, German Sports University, Cologne, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Gerhard-Garcia
authors.affiliation: Institute of Cardiovascular Research and Sports Medicine, German Sports University, Cologne, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Suhr
authors.affiliation: Institute for Experimental Medicine, University of Cologne, Cologne, Germany.
authors.forename: Juergen H
authors.initials: JH
authors.lastname: Fischer
authors.affiliation: Department of Internal Medicine I (Cardiology, Angiology, Pneumology), Friedrich- Schiller University, Jena, Germany.
authors.forename: Hans R
authors.initials: HR
authors.lastname: Figulla
authors.affiliation: Institute of Cardiovascular Research and Sports Medicine, German Sports University, Cologne, Germany.
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Bloch
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000378:metabolism; D001485:Basement Membrane / Q000378:metabolism / Q000503:physiopathology; D024141:Collagen Type IV / Q000378:metabolism; D003402:Creatine Kinase / Q000378:metabolism; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000378:metabolism / Q000502:physiology*; D005260:Female; D006321:Heart / Q000503:physiopathology*; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism; D007035:Hypothermia / Q000378:metabolism / Q000503:physiopathology; D007511:Ischemia / Q000378:metabolism / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism; D015424:Reperfusion / Q000379:methods; D015427:Reperfusion Injury / Q000378:metabolism / Q000503:physiopathology*; D013552:Swine
chemical_list: D001324:Autoantigens; D024141:Collagen Type IV; D019812:Heparan Sulfate Proteoglycans; C057112:type IV collagen alpha3 chain; C071927:perlecan; D003402:Creatine Kinase