title: Detection of extracellular genomic DNA scaffold in human thrombus: implications for the use of deoxyribonuclease enzymes in thrombolysis.
abstract: OBJECTIVE
  Mechanisms underlying transition of a thrombus susceptible to tissue plasminogen activator (TPA) fibrinolysis to one that is resistant is unclear. Demonstration of a new possible thrombus scaffold may open new avenues of research in thrombolysis and may provide mechanistic insight into thrombus remodeling.
  
  
  METHODS
  Ten human thrombus samples were collected during cases of thrombectomy and open surgical repair of abdominal aortic aneurysms (five samples < 3 d old and five samples > 1 y old). Additionally, an acute murine hindlimb ischemia model was created to evaluate thrombus samples in mice. Human sections were immunostained for the H2A/H2B/DNA complex, myeloperoxidase, fibrinogen, and von Willebrand factor. Mouse sections were immunostained with the H2A antibody. All samples were further evaluated after hematoxylin and eosin and Masson trichrome staining.
  
  
  RESULTS
  An extensive network of extracellular histone/DNA complex was demonstrated in the matrix of human ex vivo thrombus. This network is present throughout the highly cellular acute thrombus. However, in chronic thrombi, detection of the histone/DNA network was predominantly in regions of low collagen content and high cell density, which were mostly near the lumen. These regions of high cell density contained neutrophils and monocytes. Similarly, sections from the acute murine hindlimb ischemia model also exhibited extensive immunoreactivity to the histone antibody in the extracellular space within murine thrombi.
  
  
  CONCLUSIONS
  Extensive detection of genomic DNA associated with histones in the extracellular matrix of human and mouse thrombi suggest the presence of a new thrombus-associated scaffold.
authors.affiliation: Division of Vascular Imaging and Intervention, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. roklu@partners.org
authors.forename: Rahmi
authors.initials: R
authors.lastname: Oklu
authors.forename: Hassan
authors.initials: H
authors.lastname: Albadawi
authors.forename: Michael T
authors.initials: MT
authors.lastname: Watkins
authors.forename: Marc
authors.initials: M
authors.lastname: Monestier
authors.forename: Martin
authors.initials: M
authors.lastname: Sillesen
authors.forename: Stephan
authors.initials: S
authors.lastname: Wicky
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000150:complications; D004247:DNA / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000627:therapeutic use*; D004195:Disease Models, Animal; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006614:Hindlimb; D006657:Histones / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007511:Ischemia / Q000150:complications; D017078:Laser-Doppler Flowmetry; D008297:Male; D051379:Mice; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism; D018482:Muscle, Skeletal / Q000098:blood supply*; D009504:Neutrophils / Q000378:metabolism; D015912:Thrombolytic Therapy / Q000379:methods*; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D016326:Extracellular Matrix Proteins; D005343:Fibrinolytic Agents; D006657:Histones; D004247:DNA; D003851:Deoxyribonucleases