title: Myeloperoxidase and progression of aortic valve stenosis in patients undergoing hemodialysis.
abstract: OBJECTIVE
  Currently, there is an increased incidence of aortic valve stenosis (AS) in patients undergoing hemodialysis (HD), though the exact mechanisms are not fully understood. Myeloperoxidase (MPO) is a leukocyte-derived enzyme that catalyzes the formation of reactive oxygen species and is an index of oxidative stress. The study aim was to examine, immunohistochemically, the expression of MPO, using surgically resected aortic valve specimens from AS patients undergoing HD.
  
  
  METHODS
  The study population consisted of 15 HD patients and 19 non-HD patients with severe AS undergoing aortic valve replacement. Frozen aortic valve samples obtained surgically from AS patients were stained immunohistochemically with antibodies against smooth muscle cells, neutrophils, macrophages, T lymphocytes, CD31, MPO and 4-hydroxy-2-nonenal (4-HNE).
  
  
  RESULTS
  Quantitative analyses showed that the macrophage-positive area, and numbers of T lymphocytes, neutrophils, CD31-positive microvessels and MPO-positive cells in HD patients were significantly higher than in non-HD patients (macrophages, p < 0.0001; T lymphocytes, p < 0.0001; neutrophils, p < 0.0001; CD31, p < 0.0001; MPO, p < 0.0001). Moreover, the number of MPO-positive cells was positively correlated with CD31-positive microvessels and the 4-HNE-positive macrophage score (CD31, R = 0.73, p < 0.0001; 4-HNE, R = 0.49; p < 0.005).
  
  
  CONCLUSIONS
  These findings suggest that MPO is highly expressed in the aortic valves of AS patients undergoing HD. Furthermore, MPO is positively associated with neovascularization and oxidative stress, which contribute to a rapid progression of AS in HD patients.
authors.affiliation: Department of Pathology, City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Wada
authors.affiliation: Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sugioka
authors.affiliation: Department of Cardiology, Osaka City General Hospital, Osaka, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Naruko
authors.affiliation: Department of Cardiovascular Surgery, Osaka City General Hospital, Osaka, Japan,
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Department of Cardiovascular Surgery, Osaka City General Hospital, Osaka, Japan,
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Shibata
authors.affiliation: Department of Pathology, Osaka City General Hospital, Osaka, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Inoue
authors.affiliation: Department of Pathology, City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Inaba
authors.affiliation: Department of Pathology, City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ohsawa
authors.affiliation: Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Yoshiyama
authors.affiliation: Department of Pathology, City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Ueda
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000201:enzymology* / Q000473:pathology; D001024:Aortic Valve Stenosis / Q000150:complications / Q000201:enzymology* / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007676:Kidney Failure, Chronic / Q000150:complications / Q000628:therapy; D008264:Macrophages / Q000201:enzymology; D008297:Male; D009504:Neutrophils / Q000201:enzymology; D018384:Oxidative Stress; D009195:Peroxidase / Q000096:biosynthesis*; D006435:Renal Dialysis; D012189:Retrospective Studies
chemical_list: D009195:Peroxidase