title: Expression of aquaporins in bronchial tissue and lung parenchyma of patients with chronic obstructive pulmonary disease.
abstract: BACKGROUND
  Aquaporins AQP1 and AQP5 are highly expressed in the lung. Recent studies have shown that the expression of these proteins may be mechanistically involved in the airway inflammation and in the pathogenesis of chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate the expression of AQP1 and AQP5 in the bronchial tissue and the lung parenchyma of patients with COPD and COPD-resistant smokers.
  
  
  METHODS
  Using a case-control design, we selected a group of 15 subjects with COPD and 15 resistant smokers (smokers without COPD) as a control, all of whom were undergoing lung resection surgery due to a lung neoplasm. We studied the expression of AQP1 and AQP5 in the bronchial tissue and the lung parenchyma by means of immunohistochemistry and reverse-transcription real-time polymerase chain reaction. Tissue expression of AQP1 and AQP5 was semi-quantitatively assessed in terms of intensity and expression by immunohistochemistry using a 4-point scale ranging from 0 (none) to 3 (maximum).
  
  
  RESULTS
  There were no significant differences in gene expression between COPD patients and resistant smokers both in the bronchial tissue and in the lung parenchyma. However, AQP1 gene expression was 2.41-fold higher in the parenchyma of smokers with COPD compared to controls, whereas the AQP5 gene showed the opposite pattern, with a 7.75-fold higher expression in the bronchus of smokers with COPD compared with controls. AQP1 and AQP5 proteins were preferentially expressed in endothelial cells, showing a higher intensity for AQP1 (66.7% of cases with an intensity of 3, and 93.3% of subjects with an extension of 3 among patients with COPD). Subtle interstitial disease was associated with type II pneumocyte hyperplasia and an increased expression of AQP1.
  
  
  CONCLUSIONS
  This study provides pilot observations on the differences in AQP1 and AQP5 expression between COPD patients and COPD-resistant smokers. Our findings suggest a potential role for AQP1 in the pathogenesis of COPD.
authors.affiliation: Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Hospital Universitario Virgen del Rocio, Sevilla, Spain ; Instituto de Biomedicina de Sevilla (IBiS), Avda. Manuel Siurot, s/n 41013, Sevilla, Spain ; CIBER de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Calero
authors.affiliation: Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Hospital Universitario Virgen del Rocio, Sevilla, Spain ; Instituto de Biomedicina de Sevilla (IBiS), Avda. Manuel Siurot, s/n 41013, Sevilla, Spain ; CIBER de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: López-Campos
authors.affiliation: Departamento de Anatomía Patológica, Hospital Universitario Virgen del Rocio, Sevilla, Spain.
authors.forename: Lourdes Gómez
authors.initials: LG
authors.lastname: Izquierdo
authors.affiliation: Instituto de Biomedicina de Sevilla (IBiS), Avda. Manuel Siurot, s/n 41013, Sevilla, Spain.
authors.forename: Rocío
authors.initials: R
authors.lastname: Sánchez-Silva
authors.affiliation: Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Hospital Universitario Virgen del Rocio, Sevilla, Spain ; Instituto de Biomedicina de Sevilla (IBiS), Avda. Manuel Siurot, s/n 41013, Sevilla, Spain.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: López-Villalobos
authors.affiliation: Instituto de Biomedicina de Sevilla (IBiS), Avda. Manuel Siurot, s/n 41013, Sevilla, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Sáenz-Coronilla
authors.affiliation: Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Hospital Universitario Virgen del Rocio, Sevilla, Spain ; Instituto de Biomedicina de Sevilla (IBiS), Avda. Manuel Siurot, s/n 41013, Sevilla, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Arellano-Orden
authors.affiliation: Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Hospital Universitario Virgen del Rocio, Sevilla, Spain ; Instituto de Biomedicina de Sevilla (IBiS), Avda. Manuel Siurot, s/n 41013, Sevilla, Spain ; CIBER de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Montes-Worboys
authors.affiliation: Instituto de Biomedicina de Sevilla (IBiS), Avda. Manuel Siurot, s/n 41013, Sevilla, Spain ; CIBER de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Miriam
authors.initials: M
authors.lastname: Echevarría
keywords: Aquaporin; Bronchial tissue; Chronic obstructive pulmonary disease; Lung parenchyma