title: Different patterns of extracellular matrix protein expression in the convexity and the concavity of the dilated aorta with bicuspid aortic valve: preliminary results.
abstract: OBJECTIVE
  This study aimed to assess extracellular matrix protein expression patterns at the convexity (right anterolateral wall) and the concavity of the dilated ascending aorta in patients with bicuspid aortic valve disease.
  
  
  METHODS
  Aortic wall specimens were retrieved from the convexity and the concavity in 27 bicuspid aortic valve patients (12 with stenosis and 15 with regurgitation) and 6 heart donors (controls). Morphometry, immunohistochemistry, Western blot, and polymerase chain reaction were performed, focusing on matrix proteins involved in vascular remodeling.
  
  
  RESULTS
  Type I and III collagens were significantly decreased in bicuspid-associated dilated aortas versus controls (P < .001), particularly at the convexity (P < .05 vs concavity). Expression of messenger RNA for collagens was lower than normal only in the regurgitant subgroup. At immunohistochemistry, proteins whose overproduction has been demonstrated in response to abnormal wall stress, such as tenascin and fibronectin, were more expressed in the convexity than in the concavity, especially in the stenosis subgroup. Tenascin, which is produced by smooth muscle cells in the synthetic phenotype, was nearly undetectable in controls. Fewer smooth muscle cells (stenosis, P = .017; regurgitation, P = .008) and more severe elastic fiber fragmentation (P = .029 and P < .001) were observed in the convexity versus the concavity.
  
  
  CONCLUSIONS
  In bicuspid-associated aortic dilations, an asymmetric pattern of matrix protein expression was found that was consistent with the asymmetry in wall-stress distribution reported previously. Differences exist between patients with stenosis and those with regurgitation in terms of protein expression and content in the aortic wall. Further studies could clarify the relations between these findings and the pathogenesis of aortic dilatation in bicuspid aortic valve patients.
authors.affiliation: Department of Cardiothoracic and Respiratory Sciences, Second University of Naples, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cotrufo
authors.forename: Alessandro
authors.initials: A
authors.lastname: Della Corte
authors.forename: Luca S
authors.initials: LS
authors.lastname: De Santo
authors.forename: Cesare
authors.initials: C
authors.lastname: Quarto
authors.forename: Marisa
authors.initials: M
authors.lastname: De Feo
authors.forename: Gianpaolo
authors.initials: G
authors.lastname: Romano
authors.forename: Cristiano
authors.initials: C
authors.lastname: Amarelli
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Scardone
authors.forename: Franca
authors.initials: F
authors.lastname: Di Meglio
authors.forename: Germano
authors.initials: G
authors.lastname: Guerra
authors.forename: Maria
authors.initials: M
authors.lastname: Scarano
authors.forename: Serena
authors.initials: S
authors.lastname: Vitale
authors.forename: Clotilde
authors.initials: C
authors.lastname: Castaldo
authors.forename: Stefania
authors.initials: S
authors.lastname: Montagnani
mesh_terms: D000368:Aged; D001011:Aorta / Q000378:metabolism / Q000473:pathology; D001018:Aortic Diseases / Q000378:metabolism*; D001021:Aortic Valve / Q000473:pathology; D001022:Aortic Valve Insufficiency / Q000151:congenital / Q000378:metabolism*; D001024:Aortic Valve Stenosis / Q000151:congenital / Q000378:metabolism*; D024042:Collagen Type I / Q000096:biosynthesis; D024061:Collagen Type III / Q000096:biosynthesis; D004108:Dilatation, Pathologic; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D006801:Humans; D008875:Middle Aged
chemical_list: D024042:Collagen Type I; D024061:Collagen Type III; D016326:Extracellular Matrix Proteins