title: Contrast ultrasound for the quantification of deep vein thrombosis in living mice: effects of enoxaparin and P2Y12 receptor inhibition.
abstract: OBJECTIVE
  We examined the applicability of contrast-enhanced ultrasound (CEUS) for imaging of murine deep vein thrombosis (DVT) and measured the effects of enoxaparin, ticagrelor and P2Y(12) receptor deficiency in vivo.
  
  
  METHODS
  Deep vein thrombosis was induced by exposure to ferric chloride or ligation of the infrarenal vena cava of C57BL/6 mice after pretreatment with enoxaparin, ticagrelor or vehicle and in P2Y(12-/-) mice. Initial thrombus growth was visualized by intravital microscopy. Thrombi were weighed and examined by immunohistochemistry. CEUS was performed with a standard ultrasound system (Vivid 7, GE Healthcare) in the open abdominal cavity after injection of stabilized sulphur hexafluoride microbubbles.
  
  
  RESULTS
  Incubation with ferric chloride resulted in non-occluding platelet-containing thrombus growth within 15-25 min. Sham-operated mice, enoxaparin- and ticagrelor-pretreated wild-type and P2Y(12-/-) mice developed only small thrombi. After injection of the contrast agent, growing thrombi were delineated clearly as negative contrast on CEUS. Thrombus size on CEUS after 25 min was significantly smaller in enoxaparin- (0.3 ± 0.1 mm(2)) and ticagrelor-treated (0.5 ± 0.1 mm(2)) wild-type and in P2Y(12-/-) mice (0.4 ± 0.1 mm(2)) as compared with vehicle-treated wild-type mice (2.0 ± 0.3 mm(2)) in the maximal sagittal plane (P < 0.001, n = 5-10). CEUS-derived thrombus size correlated linearly with thrombus weight and also reflected the extent of ligation-induced DVT.
  
  
  CONCLUSIONS
  Contrast-enhanced ultrasound allowed the real-time quantification of DVT in living mice. Genetic and pharmacologic antithrombotic interventions were well reflected by CEUS and suggested an important role of the platelet P2Y(12) receptor in early DVT formation.
authors.affiliation: Department of Cardiology and Angiology I, University Heart Center Freiburg, Freiburg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Guenther
authors.forename: N
authors.initials: N
authors.lastname: Herr
authors.forename: M
authors.initials: M
authors.lastname: Mauler
authors.forename: T
authors.initials: T
authors.lastname: Witsch
authors.forename: F
authors.initials: F
authors.lastname: Roming
authors.forename: L
authors.initials: L
authors.lastname: Hein
authors.forename: J-M
authors.initials: JM
authors.lastname: Boeynaems
authors.forename: B
authors.initials: B
authors.lastname: Robaye
authors.forename: M
authors.initials: M
authors.lastname: Idzko
authors.forename: C
authors.initials: C
authors.lastname: Bode
authors.forename: C
authors.initials: C
authors.lastname: Von Zur Muhlen
authors.forename: D
authors.initials: D
authors.lastname: Duerschmied
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology*; D002712:Chlorides / Q000737:chemistry; D003287:Contrast Media / Q000494:pharmacology; D017984:Enoxaparin / Q000494:pharmacology*; D005290:Ferric Compounds / Q000737:chemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D045423:Microbubbles; D008853:Microscopy; D058921:Purinergic P2Y Receptor Antagonists / Q000494:pharmacology*; D058925:Receptors, Purinergic P2Y12 / Q000737:chemistry*; D015398:Signal Transduction; D013459:Sulfur Hexafluoride / Q000737:chemistry; D013927:Thrombosis / Q000188:drug therapy; D000077486:Ticagrelor; D014463:Ultrasonography; D014682:Vena Cava, Inferior / Q000473:pathology; D020246:Venous Thrombosis / Q000139:chemically induced / Q000000981:diagnostic imaging*
chemical_list: D000925:Anticoagulants; D002712:Chlorides; D003287:Contrast Media; D017984:Enoxaparin; D005290:Ferric Compounds; D058921:Purinergic P2Y Receptor Antagonists; D058925:Receptors, Purinergic P2Y12; D000077486:Ticagrelor; D000241:Adenosine; C024555:ferric chloride; D013459:Sulfur Hexafluoride
keywords: P2Y12 receptor; contrast-enhanced ultrasound; deep vein thrombosis