Endothelial cell-derived microparticles as potential biomarkers in chronic interstitial lung diseases

Background: Cell-derived microparticles (MP) are extracellular vesicles released by cells in a variety of physiological and pathological conditions. A role for endothelial cell-derived MP (EMP) as both pathogenetic effectors and biomarkers of pulmonary fibrosis (PF) has been postulated. Aim: To investigate the potential role of EMP as a biomarkers in PF. Patients and Methods: 14 consecutive patients with interstitial lung disease and 18 normal individuals were investigated. Platelet poor plasma was obtained by two subsequent centrifugations: 1,500 xg for 15 minutes and 13,000 xg for 2 minutes. EMP were analysed by FACS and discriminated first by size, as events conforming to a light scatter distribution within the 0.5-0.9 μm range and further identifies them as annexin V, carboxyfluorescein diacetate succinimidyl ester (CFSE), CD62e and CD31 positive events. A ROC curve was built to describe the potential diagnostic power of this approach. Results: The number of EMP was significantly higher in the PF group compared to controls (Fig 1a; mean±SEM;**p<0.001). Figure 1b shows the ROC curve. Area under the curve was 0.95±0.04 (SE); p<0.0001. An arbitrary cut-off of 104 events/min corresponded to a sensitivity of 93%, a specificity of 83% and a likelihood ratio of 5.57. Conclusions: The results of this preliminary pilot study confirm a potential role for EMP as a biomarker for PF and warrant further research.