Sequential analysis of surfactant, lung function and inflammation in cystic fibrosis patients.

Reinhold Schmidt,Manfred Ballmann,Ernst Rietschel,Robert Essl,Felix Ratjen,The Beat Study Group ,Karl Paul,Matthias Griese

doi:10.1186/1465-9921-6-133

Abstract

BackgroundIn a cross-sectional analysis of cystic fibrosis (CF) patients with mild lung disease, reduced surfactant activity was correlated to increased neutrophilic airway inflammation, but not to lung function. So far, longitudinal measurements of surfactant function in CF patients are lacking and it remains unclear how these alterations relate to the progression of airway inflammation as well as decline in pulmonary function over time.MethodsAs part of the BEAT trial, a longitudinal study to assess the course of airway inflammation in CF, we studied lung function, surfactant function and endobronchial inflammation using bronchoalveolar lavage fluid from 20 CF patients with normal pulmonary function (median FEV1 94% of predicted) at three times over a three year period.ResultsThere was a progressive loss of surfactant function, assessed as minimal surface tension. The decline in surfactant function was negatively correlated to an increase in neutrophilic inflammation and a decrease in lung function, assessed by FEV1, MEF75/25%VC, and MEF25%VC. The concentrations of the surfactant specific proteins A, C and D did not change, whereas SP-B increased during this time period.ConclusionOur findings suggest a link between loss of surfactant function driven by progressive airway inflammation and loss of small airway function in CF patients with limited lung disease.

Highlights

In a cross-sectional analysis of cystic fibrosis (CF) patients with mild lung disease, reduced surfactant activity was correlated to increased neutrophilic airway inflammation, but not to lung function
As part of the BEAT trial, a longitudinal study to assess the course of airway inflammation in CF, we studied lung function, surfactant function and endobronchial inflammation using bronchoalveolar lavage fluid from 20 CF patients with normal pulmonary function at three times over a three year period
The decline in surfactant function was negatively correlated to an increase in neutrophilic inflammation and a decrease in lung function, assessed by FEV1, MEF75/25%VC, and MEF25%VC

Summary

Introduction

In a cross-sectional analysis of cystic fibrosis (CF) patients with mild lung disease, reduced surfactant activity was correlated to increased neutrophilic airway inflammation, but not to lung function. Pulmonary surfactant is of critical importance for the maintenance of airspace patency during the respiratory cycle, especially at lower airway pressures at end-expiration. These biophysical functions are predominantly related to surfactant lipids [2,3], surfactant proteins (SP-) B and -C, as well as SP-A which contributes to resistance against inhibition of surfactant activity by products of inflammation. The degree of surfactant dysfunction was inversely correlated with neutrophilic endobronchial inflammation, but no correlation was observed with flows at low lung volumes (MEF25%VC or MEF25/75%VC)

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Results

Conclusion