title: Preliminary study of the cellular characteristics of primary bronchial fibroblasts in patients with asthma: expression of alpha-smooth muscle actin, fibronectin containing extra type III domain A, and smoothelin.
abstract: BACKGROUND
  The relationship between fibroblasts, myofibroblasts, and smooth muscle cells within the airway wall remains poorly understood.
  
  
  OBJECTIVE
  The cellular characteristics of primary bronchial fibroblasts from patients with asthma were investigated by evaluating the expression of 3 proteins: alpha-smooth muscle actin (SMA), fibronectin containing extra type III domain A (EDAcFN), and smoothelin.
  
  
  METHODS
  Expression of SMA, EDAcFN, and smoothelin was evaluated in primary fibroblasts from 3 patients with asthma of varying symptom severity, embryonic fibroblasts, and a healthy control. In addition, primary bronchial fibroblasts from patients with asthma were assessed for SMA at various incubation times (4 hours to 76 hours) and with different extracellular matrices (ECMs). Immunofluorescence was assessed by manually counting cells that stained positively as fine filamentous structures under a fluorescence microscope.
  
  
  RESULTS
  Expression of filamentous SMA tended to increase with the length of incubation. The positive to total cell ratio for filamentous cells did not differ significantly between the various kinds of ECMs onto which cells were plated (P > .05). Primary bronchial fibroblasts from asthma patients produced more prominent expression of EDAcFN than control fibroblasts. Smoothelin was not expressed in any fibroblasts.
  
  
  CONCLUSIONS
  More than 50% of primary bronchial fibroblasts were defined as myofibroblasts. Primary bronchial fibroblasts in patients with asthma had more potential for tissue fibrosis than control fibroblasts. No mature smooth muscle cells were observed in primary bronchial fibroblasts in patients with asthma.
authors.affiliation: Department of Internal Medicine, College of Medicine, Dong-A University, Busan, South Korea.
authors.forename: Y H
authors.initials: YH
authors.lastname: Nam
authors.forename: S K
authors.initials: SK
authors.lastname: Lee
authors.forename: D
authors.initials: D
authors.lastname: Sammut
authors.forename: D E
authors.initials: DE
authors.lastname: Davies
authors.forename: P H
authors.initials: PH
authors.lastname: Howarth
mesh_terms: D000199:Actins / Q000096:biosynthesis*; D000328:Adult; D001249:Asthma / Q000378:metabolism* / Q000473:pathology; D001980:Bronchi / Q000166:cytology*; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000096:biosynthesis*; D005347:Fibroblasts / Q000145:classification / Q000166:cytology / Q000378:metabolism*; D005353:Fibronectins / Q000096:biosynthesis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009124:Muscle Proteins / Q000096:biosynthesis*; D009130:Muscle, Smooth / Q000166:cytology; D058628:Myofibroblasts
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D003598:Cytoskeletal Proteins; C527677:FNDC3A protein, human; D005353:Fibronectins; D009124:Muscle Proteins; C100762:SMTN protein, human