Circulating surfactant protein D as a potential lung-specific biomarker of health outcomes in COPD: a pilot study

Don D Sin,Rochelle Leung,Sf Paul Man,Wen Q Gan

doi:10.1186/1471-2466-7-13

Abstract

BackgroundThere is a paucity of surrogate lung-specific biological markers that can be used to track disease progression and predict clinical outcomes in chronic obstructive pulmonary disease (COPD). The principal aim of this pilot study was to determine whether circulating surfactant protein D (SPD) or Clara Cell protein-16 (CC16) levels are associated with lung function or health status in patients with severe COPD.MethodsWe studied 23 patients with advanced COPD. Lung function measurements, Chronic Respiratory Disease Questionnaire (CRQ) scores, and serum levels of SPD, CC16, and C-reactive protein (CRP) were determined at baseline and at 3 months.ResultsAt baseline, FEV1 was inversely associated with serum SPD levels (P = 0.045) but not with CC16 (P = 0.675) or CRP levels (P = 0.549). Over a 3 month period, changes in SPD levels correlated significantly with changes in CRQ scores (adjusted P = 0.008) such that patients who had the largest declines in serum SPD levels experienced the largest gains in health status. The association was particularly notable between circulating SPD level and the dyspnea domain of the CRQ score (P = 0.018). Changes in CC16 or CRP levels did not correlate with changes in CRQ scores.ConclusionChanges in serum SPD levels tracked well with changes in health status over a 3 month period in patients with severe COPD. These data suggest that circulating SPD levels may be useful biomarkers to track health outcomes of COPD patients.

Highlights

There is a paucity of surrogate lung-specific biological markers that can be used to track disease progression and predict clinical outcomes in chronic obstructive pulmonary disease (COPD)
Surfactant protein D (SPD) and Clara cell protein-16 (CC16) are two proteins that are produced predominantly in the lungs and as such may be useful in tracking disease progression and health status of COPD patients [6]
The principal aim of this pilot study was to determine whether circulating surfactant protein D (SPD) and Clara Cell protein-16 (CC16) are associated with lung function and health status of patients with advanced COPD

Summary

Introduction

There is a paucity of surrogate lung-specific biological markers that can be used to track disease progression and predict clinical outcomes in chronic obstructive pulmonary disease (COPD). One major limitation of drug development has been the paucity of surrogate biological markers that can be used to track disease progression (i.e. progressive decline in lung function and increase in symptoms such as dyspnea) and predict clinical outcomes [3]. CRP is a good predictor of cardiovascular events, it is not a good marker of respiratory health outcomes or rate of decline in lung function [4]. This may not be surprising given that the predominant source of circulating CRP is the liver and not the lungs [5]. The principal aim of this pilot study was to determine whether circulating SPD and CC16 are associated with lung function and health status of patients with advanced COPD

Methods

Results

Discussion

Conclusion