title: Fibrinolysis inhibitors in plaque stability: a morphological association of PAI-1 and TAFI in advanced carotid plaque.
abstract: Essentials Fibrinolysis inhibitors are localized in advanced atheroma by immunohistology of endarterectomies. Neovascular endothelium/neocapillaries show thrombin-activatable fibrinolysis inhibitor (TAFI). Macrophage areas show free plasminogen activator inhibitor (PAI-1), notably in the vulnerable part. Free PAI-1 and TAFI stabilize active plaque area by inhibition of fibrinolysis and inflammation.
  
  
  
  Background Fibrinolysis plays an important role in destabilization of atherosclerotic plaques and is tightly regulated by specific inhibitors. Objective The fibrinolysis inhibitors plasminogen activator inhibitor type-1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (TAFI) were quantified and described in the morphological context of advanced carotid plaques American Heart Association VI-VIII to elucidate their role in plaque stability. Methods Immunohistochemistry in serial sections along the longitudinal axis of endarterectomies from patients with symptomatic carotid stenosis (n = 19) were studied using an antibody specific for free PAI-1 (I205), an antibody with high affinity for TAFI/TAFIa (CP17) and established antibodies for smooth muscle cells (α-actin), endothelial cells (von Willebrand factor [VWF]), macrophages (CD68) and platelets (CD42). Results PAI-1 and TAFI show a specific distribution in these advanced plaques with a maximum corresponding to the internal carotid artery (ICA). Free PAI-1 was mainly detected in macrophages and in intravascular thrombi, and TAFI in endothelial cells (ECs) but also macrophages. The one-way ANOVA analysis with Bonferroni's correction showed a significant increase of macrophages and ECs, TAFI and PAI-1 in areas with high neovascularization in endarterectomy sections corresponding to ICA. High Spearman factors for TAFI, PAI-1 and VWF indicate neovascularization as the main source of plasma proteins, transported by platelets into the atheroma (PAI-1) or expressed by ECs (TAFI). CD68 was highly associated with VWF, PAI-1 and especially TAFI, underlining the role of macrophages in fibrinolytic activity and inflammation. Conclusion The abundance of free PAI-1 and TAFI in the plaque may inhibit plasmin generation and thereby counteract plaque destabilization by fibrinolysis, cell migration and inflammation.
authors.affiliation: CVMD IMED AstraZeneca R&D Mölndal, Mölndal, Sweden.
authors.forename: A-C
authors.initials: AC
authors.lastname: Jönsson Rylander
authors.affiliation: Personalised Healthcare and Biomarkers, AstraZeneca R&D Mölndal, Mölndal, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Lindgren
authors.affiliation: CVMD IMED AstraZeneca R&D Mölndal, Mölndal, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Deinum
authors.affiliation: Sahlgrenska Center for Cardiovascular and Metabolic Research, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: G M L
authors.initials: GM
authors.lastname: Bergström
authors.affiliation: CSM Pathology Sciences, AstraZeneca R&D Mölndal, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Böttcher
authors.affiliation: CVMD GMed, AstraZeneca R&D Mölndal, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Kalies
authors.affiliation: CVMD Translational Medicine Unit, Early Clinical Development, AstraZeneca R&D Mölndal, Mölndal, Sweden.|Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Wåhlander
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000494:pharmacology; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D025901:Carboxypeptidase B2 / Q000378:metabolism*; D002339:Carotid Arteries / Q000473:pathology; D016893:Carotid Stenosis / Q000473:pathology*; D004691:Endarterectomy; D005260:Female; D005340:Fibrinogen / Q000494:pharmacology; D005341:Fibrinolysin / Q000494:pharmacology; D005342:Fibrinolysis / Q000187:drug effects*; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D010865:Pilot Projects; D058226:Plaque, Atherosclerotic / Q000473:pathology; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism*; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology; D013927:Thrombosis; D014841:von Willebrand Factor / Q000378:metabolism; D000097382:CD68 Molecule
chemical_list: D000925:Anticoagulants; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D025901:Carboxypeptidase B2; D005340:Fibrinogen; D005341:Fibrinolysin; D017395:Plasminogen Activator Inhibitor 1; D019038:Platelet Glycoprotein GPIb-IX Complex; D013917:Thrombin; D014841:von Willebrand Factor; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C051321:SERPINE1 protein, human
keywords: Endarterectomy; Plasminogen Activator Inhibitor 1; fibrinolysis; immunohistochemistry; thrombin-activatable fibrinolysis inhibitor