title: Stabilizing role of platelet P2Y(12) receptors in shear-dependent thrombus formation on ruptured plaques.
abstract: BACKGROUND
  In most models of experimental thrombosis, healthy blood vessels are damaged. This results in the formation of a platelet thrombus that is stabilized by ADP signaling via P2Y(12) receptors. However, such models do not predict involvement of P2Y(12) in the clinically relevant situation of thrombosis upon rupture of atherosclerotic plaques. We investigated the role of P2Y(12) in thrombus formation on (collagen-containing) atherosclerotic plaques in vitro and in vivo, by using a novel mouse model of atherothrombosis.
  
  
  METHODS
  Plaques in the carotid arteries from Apoe(-/-) mice were acutely ruptured by ultrasound treatment, and the thrombotic process was monitored via intravital fluorescence microscopy. Thrombus formation in vitro was assessed in mouse and human blood perfused over collagen or plaque material under variable conditions of shear rate and coagulation. Effects of two reversible P2Y(12) blockers, ticagrelor (AZD6140) and cangrelor (AR-C69931MX), were investigated.
  
  
  RESULTS
  Acute plaque rupture by ultrasound treatment provoked rapid formation of non-occlusive thrombi, which were smaller in size and unstable in the presence of P2Y(12) blockers. In vitro, when mouse or human blood was perfused over collagen or atherosclerotic plaque material, blockage or deficiency of P2Y(12) reduced the thrombi and increased embolization events. These P2Y(12) effects were present at shear rates >500 s(-1), and they persisted in the presence of coagulation. P2Y(12)-dependent thrombus stabilization was accompanied by increased fibrin(ogen) binding.
  
  
  CONCLUSIONS
  Platelet P2Y(12) receptors play a crucial role in the stabilization of thrombi formed on atherosclerotic plaques. This P2Y(12) function is restricted to high shear flow conditions, and is preserved in the presence of coagulation.
authors.affiliation: Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
authors.forename: Reyhan
authors.initials: R
authors.lastname: Nergiz-Unal
authors.forename: Judith M E M
authors.initials: JM
authors.lastname: Cosemans
authors.forename: Marion A H
authors.initials: MA
authors.lastname: Feijge
authors.forename: Paola E J
authors.initials: PE
authors.lastname: van der Meijden
authors.forename: Robert F
authors.initials: RF
authors.lastname: Storey
authors.forename: J J J
authors.initials: JJ
authors.lastname: van Giezen
authors.forename: Mirjam G A
authors.initials: MG
authors.lastname: oude Egbrink
authors.forename: Johan W M
authors.initials: JW
authors.lastname: Heemskerk
authors.forename: Marijke J E
authors.initials: MJ
authors.lastname: Kuijpers
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000150:complications* / Q000473:pathology; D001777:Blood Coagulation; D002341:Carotid Artery Thrombosis / Q000473:pathology; D004195:Disease Models, Animal; D004617:Embolism / Q000209:etiology*; D018056:Hemorheology; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D010477:Perfusion; D058925:Receptors, Purinergic P2Y12 / Q000502:physiology*; D013927:Thrombosis / Q000473:pathology*
chemical_list: C548577:P2ry12 protein, mouse; D058925:Receptors, Purinergic P2Y12
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