title: Proteomic analysis of intraluminal thrombus highlights complement activation in human abdominal aortic aneurysms.
abstract: OBJECTIVE
  To identify proteins related to intraluminal thrombus biological activities that could help to find novel pathological mechanisms and therapeutic targets for human abdominal aortic aneurysm (AAA).
  
  
  RESULTS
  Tissue-conditioned media from patients with AAA were analyzed by a mass spectrometry-based strategy using liquid chromatography coupled to tandem mass spectrometry. Global pathway analysis by Ingenuity software highlighted the presence of several circulating proteins, among them were proteins from the complement system. Complement C3 concentration and activation were assessed in plasma from AAA patients (small AAA, AAA diameter=3-5 cm and large AAA, AAA diameter >5 cm), showing decreased C3 levels and activation in large AAA patients. No association of a combination of single-nucleotide polymorphisms in complement genes between large and small AAA patients was observed. Intense extracellular C3 inmunostaining, along with C9, was observed in AAA thrombus. Analysis of C3 in AAA tissue homogenates and tissue-conditioned media showed increased levels of C3 in AAA thrombus, as well as proteolytic fragments (C3a/C3c/C3dg), suggesting its local deposition and activation. Finally, the functional role of local complement activation in polymorphonuclear (PMN) cell activation was tested, showing that C3 blockade by anti-C3 antibody was able to decrease thrombus-induced neutrophil chemotaxis and reactive oxygen species production.
  
  
  CONCLUSIONS
  A decrease of systemic C3 concentration and activity in the later stages of AAA associated with local complement retention, consumption, and proteolysis in the thrombus could induce PMN chemotaxis and activation, playing a detrimental role in AAA progression.
authors.affiliation: Vascular Research Lab, IIS-Fundación Jiménez Diaz-Autonoma University, Madrid, Spain. jlmartin@fjd.es
authors.forename: Roxana
authors.initials: R
authors.lastname: Martinez-Pinna
authors.forename: Julio
authors.initials: J
authors.lastname: Madrigal-Matute
authors.forename: Carlos
authors.initials: C
authors.lastname: Tarin
authors.forename: Elena
authors.initials: E
authors.lastname: Burillo
authors.forename: Margarita
authors.initials: M
authors.lastname: Esteban-Salan
authors.forename: Carlos
authors.initials: C
authors.lastname: Pastor-Vargas
authors.forename: Jes S
authors.initials: JS
authors.lastname: Lindholt
authors.forename: Juan A
authors.initials: JA
authors.lastname: Lopez
authors.forename: Enrique
authors.initials: E
authors.lastname: Calvo
authors.forename: Melina Vega
authors.initials: MV
authors.lastname: de Ceniga
authors.forename: Olivier
authors.initials: O
authors.lastname: Meilhac
authors.forename: Jesus
authors.initials: J
authors.lastname: Egido
authors.forename: Luis M
authors.initials: LM
authors.lastname: Blanco-Colio
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Michel
authors.forename: Jose L
authors.initials: JL
authors.lastname: Martin-Ventura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000453:epidemiology / Q000378:metabolism* / Q000473:pathology*; D001323:Autoantibodies / Q000378:metabolism; D002633:Chemotaxis / Q000502:physiology; D002853:Chromatography, Liquid / Q000379:methods; D003176:Complement C3 / Q000235:genetics / Q000378:metabolism; D003186:Complement C9 / Q000235:genetics / Q000378:metabolism; D017077:Culture Media, Conditioned / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000166:cytology / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D040901:Proteomics / Q000379:methods*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012307:Risk Factors; D053719:Tandem Mass Spectrometry / Q000379:methods; D013927:Thrombosis / Q000453:epidemiology / Q000378:metabolism* / Q000473:pathology*
chemical_list: D001323:Autoantibodies; D003176:Complement C3; D003186:Complement C9; D017077:Culture Media, Conditioned; D017382:Reactive Oxygen Species
keywords: aortic aneurysm, abdominal; complement system proteins; inflammation; neutrophils; thrombosis