title: Obstruction of St Jude Medical valves in the aortic position: histology and immunohistochemistry of pannus.
abstract: OBJECTIVE
  This study aims to reveal the morphological, histological, and immunohistochemical mechanism of pannus formation using resected pannus tissue from patients with prosthetic valve dysfunction.
  
  
  METHODS
  Eleven patients with prosthetic valve (St Jude Medical valve) dysfunction in the aortic position who underwent reoperation were studied. We used specimens of resected pannus for histological staining (hematoxylin and eosin, Grocott's, azan, elastica van Gieson) and immunohistochemical staining (transforming growth factor-beta, transforming growth factor-beta receptor 1, alpha-smooth muscle actin, desmin, epithelial membrane antigen, CD34, factor VIII, CD68KP1, matrix metalloproteinase-1, matrix metalloproteinase-3, and matrix metalloproteinase-9).
  
  
  RESULTS
  Pannus without thrombus was observed at the periannulus of the left ventricular septal side; it extended into the pivot guard, interfering with the movement of the straight edge of the leaflet. The histological staining demonstrated that the specimens were mainly constituted with collagen and elastic fibrous tissue accompanied by endothelial cells, chronic inflammatory cells infiltration, and myofibroblasts. The immunohistochemical findings showed significant expression of transforming growth factor-beta, transforming growth factor-beta receptor 1, CD34, and factor VIII in the endothelial cells of the lumen layer; strong transforming growth factor-beta receptor 1, alpha-smooth muscle actin, desmin, and epithelial membrane antigen in the myofibroblasts of the media layer; and transforming growth factor-beta, transforming growth factor-beta receptor 1, and CD68KP1 in macrophages of the stump lesion.
  
  
  CONCLUSIONS
  Pannus appeared to originate in the neointima in the periannulus of the left ventricular septum. The structure of the pannus consisted of myofibroblasts and an extracellular matrix such as collagen fiber. The pannus formation after prosthetic valve replacement may be associated with a process of periannular tissue healing via the expression of transforming growth factor-beta.
authors.affiliation: Departments of Surgery and Pathology, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan. tesshi@med.kurume-u.ac.jp
authors.forename: Hideki
authors.initials: H
authors.lastname: Teshima
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Hayashida
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Yano
authors.forename: Masaru
authors.initials: M
authors.lastname: Nishimi
authors.forename: Eiki
authors.initials: E
authors.lastname: Tayama
authors.forename: Shuji
authors.initials: S
authors.lastname: Fukunaga
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Akashi
authors.forename: Takemi
authors.initials: T
authors.lastname: Kawara
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Aoyagi
mesh_terms: D000199:Actins / Q000096:biosynthesis; D030201:Activin Receptors, Type I / Q000096:biosynthesis; D000368:Aged; D015703:Antigens, CD / Q000096:biosynthesis; D001021:Aortic Valve / Q000378:metabolism / Q000473:pathology* / Q000601:surgery*; D001024:Aortic Valve Stenosis / Q000175:diagnosis* / Q000378:metabolism; D002455:Cell Division / Q000502:physiology; D015150:Echocardiography, Doppler; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D015743:Giant Cells, Foreign-Body / Q000166:cytology / Q000378:metabolism; D006325:Heart Atria / Q000378:metabolism / Q000473:pathology; D006346:Heart Septum / Q000378:metabolism / Q000473:pathology; D006350:Heart Valve Prosthesis; D006352:Heart Ventricles / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007564:Japan; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000096:biosynthesis; D008875:Middle Aged; D018396:Mucin-1 / Q000096:biosynthesis; D011474:Prosthesis Design; D011475:Prosthesis Failure; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000096:biosynthesis; D012086:Reoperation; D013925:Thromboplastin / Q000096:biosynthesis; D013927:Thrombosis / Q000175:diagnosis / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000096:biosynthesis
chemical_list: D000199:Actins; D015703:Antigens, CD; D018396:Mucin-1; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D013925:Thromboplastin; D017346:Protein Serine-Threonine Kinases; D030201:Activin Receptors, Type I; D000077293:Receptor, Transforming Growth Factor-beta Type I; D020782:Matrix Metalloproteinases