title: Smooth muscle cells of human intracranial aneurysms assume phenotypic features similar to those of the atherosclerotic plaque.
abstract: OBJECTIVE
  Characterize the phenotypic features of smooth muscle cells (SMCs) in the wall of human saccular intracranial aneurysms (sIAs).
  
  
  RESULTS
  We investigated by means of immunohistochemistry the expression of the cytoskeletal differentiation markers α-smooth muscle actin (α-SMA), smooth muscle myosin heavy chains (SMMHCs), and smoothelin in 26 sIAs and 15 nonaneurysmal cerebral arteries. In addition, S100A4, a recently identified marker of dedifferentiated SMCs in atherosclerotic plaques, was also investigated. Six sIAs and 5 nonaneurysmal arteries were used for morphometric analysis. sIAs displayed a significant medial atrophy compared with nonaneurysmal cerebral arteries; moreover, sIA SMCs showed marked decrease of α-SMA and SMMHCs expression and disappearance of smoothelin. Unexpectedly, S100A4 was strongly up-regulated in media SMCs of sIAs.
  
  
  CONCLUSIONS
  In sIAs, media SMCs acquire a dedifferentiated phenotype and show de novo expression of S100A4, characteristic features of atherosclerotic plaque SMCs.
authors: Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors: Matteo
authors: M
authors: Coen
authors: Karim
authors: K
authors: Burkhardt
authors: Philippe
authors: P
authors: Bijlenga
authors: Giulio
authors: G
authors: Gabbiani
authors: Karl
authors: K
authors: Schaller
authors: Enikö
authors: E
authors: Kövari
authors: Daniel A
authors: DA
authors: Rüfenacht
authors: Diego San Millán
authors: DS
authors: Ruíz
authors: Giampaolo
authors: G
authors: Pizzolato
authors: Marie-Luce
authors: ML
authors: Bochaton-Piallat
mesh_terms: D000199:Actins / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D054337:Cell Dedifferentiation; D002454:Cell Differentiation; D002536:Cerebral Arteries / Q000378:metabolism / Q000473:pathology; D003598:Cytoskeletal Proteins / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D002532:Intracranial Aneurysm / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009124:Muscle Proteins / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology*; D018995:Myosin Heavy Chains / Q000378:metabolism; D010641:Phenotype; D058226:Plaque, Atherosclerotic / Q000378:metabolism* / Q000473:pathology*; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins / Q000378:metabolism
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D015415:Biomarkers; D003598:Cytoskeletal Proteins; D009124:Muscle Proteins; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; C100762:SMTN protein, human; C077591:S100A4 protein, human; D018995:Myosin Heavy Chains
keywords: Atherosclerosis; CD68; Smooth muscle myosin heavy chains; Smoothelin; α-smooth muscle actin