mRNA and miRNA Airway Inflammatory Markers

Rationale:There is an increased interest to identify sensitive airway biomarkers in order to evaluate the potential and efficacy of anti-inflammatory and -remodelling therapeutic interventions. Biomarkers should be easily obtainable, reliable and valid. In COPD, easily obtainable would suggest use of blood, or more directly associated with the airways: sputum or epithelial brushes. Sputum is an obvious opportunity. It has been shown that gene expression changes in the nasal mucosa might be used as suitable surrogate for epithelial cells of the lower airways in patients with airway inflammatory diseases. However, further studies are needed to validate these assumptions. Measurement of messenger RNA, and of micro RNA derived from sputum samples and nasal brushes would fulfil the ease of use required of a biomarker. Messenger RNA would allow for easier quantification in variable dilution samples (sputum). The Groningen Research Institute for Asthma and COPD (GRIAC research group) has experience with sputum and nasal brushes, mRNA and miRNA, but more information is needed on especially reproducibility of the measurements, as well as on responsivity. Both are a prerequisite when designing new intervention trials with such biomarkers. Therefore, the aim of this study is to investigate cytokine messenger and microRNA level expression of IL-6, IL-8, IL-17, TNF-alpha, MCP-1, MIP-1 beta and TGF-beta regarding their reproducibility and responsivity in induced sputum and nasal mucosa of COPD patients in order to assess their potential as an objective outcome measure. The primary objectives of this prospective pilot study are the determination of the reproducibility and responsivity of mRNA level expression of IL-6, IL-8, TNF-alpha, MCP-1, MIP-1 beta, ECP and TGF-beta as airway inflammatory markers in induced sputum as well as mRNA and miRNA expression levels of IL-6, IL-8, IL-17, TNF-alpha, MCP-1, MIP-1 beta and TGF-beta as airway inflammatory markers in nasal mucosa. The secondary objective includes the analyses of the measurement characteristics of inflammation cell profiles, LTB4 and protein levels of IL-6, IL-8, TNF-alpha, MCP-1, MIP-1 beta, ECP and TGF-beta. Twenty COPD patients with an initial COPD exacerbation will be followed for a period of seven weeks for three consecutive visits The main parameters of induced sputum samples will be mRNA level expression of IL-6, IL-8, TNF-alpha, MCP-1, MIP-1 beta and TGF-beta. The main parameters of nasal mucosa samples will be mRNA and miRNA level expression of IL-6, IL-8, IL-17, TNF-alpha, MCP-1, MIP-1 beta and TGF-beta. To allow for full perspective on the outcomes, inflammatory cell profiles, Leukotriene B4 (LTB4) and protein levels of IL-6, IL-8, TNF-alpha, MCP-1, MIP-1 beta, eosinophilic cationic protein (ECP) and TGF-beta in sputum will be assessed.