title: Nuclear factor κ-B is activated in the pulmonary vessels of patients with end-stage idiopathic pulmonary arterial hypertension.
abstract: OBJECTIVE
  To assess activation of the inflammatory transcription factor NF-kappa B (NF-κB) in human idiopathic pulmonary arterial hypertension (PAH).
  
  
  BACKGROUND
  Idiopathic PAH is a severe progressive disease characterized by pulmonary vascular remodeling and excessive proliferation of vascular cells. Increasing evidence indicates that inflammation is important in disease pathophysiology.
  
  
  METHODS
  NF-κB-p65 and CD68, CD20 and CD45 were measured by immunohistochemistry and confocal microscopy on lung specimens from patients with idiopathic PAH (n = 12) and controls undergoing lung surgery (n = 14). Clinical data were recorded for all patients including invasive pulmonary hemodynamics for the PAH patients. Immunohistochemical images were analyzed by blinded observers to include standard pulmonary vascular morphometry; absolute macrophage counts/mm(2) and p65-positivity (p65+) using composite images and image-analysis software; and cytoplasmic:nuclear p65+ of individual pulmonary arterial endothelial and smooth muscle cells (PASMC) in 10-20 pulmonary arteries or arterioles per subject. The expression of ET-1 and CCL5 (RANTES) in whole lung was determined by RT-qPCR.
  
  
  RESULTS
  Macrophage numbers were increased in idiopathic PAH versus controls (49.0±4.5 vs. 7.95±1.9 macrophages/100 mm(2), p<0.0001): these macrophages demonstrated more nuclear p65+ than in macrophages from controls (16.9±2.49 vs. 3.5±1.25%, p<0.001). An increase in p65+ was also seen in perivascular lymphocytes in patients with PAH. Furthermore, NF-κB activation was increased in pulmonary arterial endothelial cells (62.3±2.9 vs. 14.4±3.8, p<0.0001) and PASMC (22.6±2.3 vs. 11.2±2.0, p<0.001) in patients with PAH versus controls, with similar findings in arterioles. Gene expression of both ET-1 mRNA ((0.213±0.069 vs. 1.06±0.23, p<0.01) and CCL5 (RANTES) (0.16±0.045 vs. 0.26±0.039, p<0.05) was increased in whole lung homogenates from patients with PAH.
  
  
  CONCLUSIONS
  NF-κB is activated in pulmonary macrophages, lymphocytes, endothelial and PASMC in patients with end-stage idiopathic PAH. Future research should determine whether NF-κB activation is a driver or bystander of pulmonary vascular inflammation and if the former, its potential role as a therapeutic target.
authors.affiliation: Unit of Critical Care, Royal Brompton Hospital, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Price
authors.forename: Gaetano
authors.initials: G
authors.lastname: Caramori
authors.forename: Frederic
authors.initials: F
authors.lastname: Perros
authors.forename: Chao
authors.initials: C
authors.lastname: Meng
authors.forename: Natalia
authors.initials: N
authors.lastname: Gambaryan
authors.forename: Peter
authors.initials: P
authors.lastname: Dorfmuller
authors.forename: David
authors.initials: D
authors.lastname: Montani
authors.forename: Paolo
authors.initials: P
authors.lastname: Casolari
authors.forename: Jie
authors.initials: J
authors.lastname: Zhu
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Dimopoulos
authors.forename: Dongmin
authors.initials: D
authors.lastname: Shao
authors.forename: Barbara
authors.initials: B
authors.lastname: Girerd
authors.forename: Sharon
authors.initials: S
authors.lastname: Mumby
authors.forename: Alastair
authors.initials: A
authors.lastname: Proudfoot
authors.forename: Mark
authors.initials: M
authors.lastname: Griffiths
authors.forename: Alberto
authors.initials: A
authors.lastname: Papi
authors.forename: Marc
authors.initials: M
authors.lastname: Humbert
authors.forename: Ian M
authors.initials: IM
authors.lastname: Adcock
authors.forename: S John
authors.initials: SJ
authors.lastname: Wort
mesh_terms: D000368:Aged; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D006976:Hypertension, Pulmonary / Q000401:mortality*; D007150:Immunohistochemistry; D008168:Lung / Q000378:metabolism; D008297:Male; D016328:NF-kappa B / Q000378:metabolism*; D011651:Pulmonary Artery / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D016328:NF-kappa B