Expression of acute-phase cytokines, surfactant proteins, and epithelial apoptosis in small airways of human acute respiratory distress syndrome
Journal of Critical Care, 08/03/2012
Pires–Neto RC et al. – Distal airways are involved in acute respiratory distress syndrome (ARDS) lung inflammation and show a high expression of proinflammatory interleukins in both airway epithelial and inflammatory cells. Apoptosis may not be a major mechanism of airway epithelial cell death in ARDS.Methods
- The authors studied the lungs of 31 patients with ARDS (Pao2/fraction of inspired oxygen≤200, 45±14years, 16 men) and 11 controls (52±16years, 7 men) submitted to autopsy and quantified the expression of interleukin (IL) 6, IL-8, surfactant proteins (SP) A and SP-B in the epithelium of small airways using immunohistochemistry and image analysis.
- In addition, an index of airway epithelial apoptosis was determined by the terminal deoxynucleotidyl transferase-mediated deoxyuridine-triphosphatase nick-end labeling assay, caspase 3, and Fas/Fas ligand expression.
- The density of inflammatory cells expressing IL-6 and IL-8 within the small airway walls was also quantified.
- Acute respiratory distress syndrome airways showed an increase in the epithelial expression of IL-8 (P=.006) and an increased density of inflammatory cells expressing IL-6 (P=.004) and IL-8 (P<.001) compared with controls.
- There were no differences in SP-A and SP-B epithelium expression or in epithelial apoptosis index between ARDS and controls.