Table 6 Summary of studies on EVs in COPD exacerbation

Takahashi et al., 2012 [45]

Increased circulating endothelial microparticles in COPD patients: a potential biomarker for COPD exacerbation susceptibility

To compare EMP numbers in stable COPD patients with those during and after exacerbation

Ex vivo

Human

VE-cadherin (CD144 +), PECAM (CD31+/41−) and E-selectin (CD62E+) EMPs of pulmonary capillary origin were significantly more numerous in the stable COPD patients than in the healthy non-COPD volunteers, with further increase in the exacerbated phase. Baseline E-selectin EMP levels were significantly higher in COPD patients with frequent exacerbations than patients without, indicative of endothelial damage during exacerbation

Eltom et al., 2014 [46]

Respiratory infections cause the release of extracellular vesicles: implication in exacerbation of asthma/COPD

Investigate whether respiratory infections cause the release of EVs in the airway and that the raised ATP levels, present in respiratory disease, triggers the release of IL-1b/IL-18, neutrophilia and subsequent disease exacerbations

In vitro

In vivo/ex vivo

Mice

Ex vivo

Human

Respiratory infections, bacterial and viral, can trigger the release of functional EVs in mice and man. Upon ATP activation, the EVs released IL-1b and IL-18 in a P2X7/caspase-1 axis dependent manner resulting in exacerbated neutrophilia

Tan et al., 2017 [47]

Elevated levels of circulating exosomes in COPD patients are associated with systemic inflammation

Investigate whether the levels of circulating exosomes (CD9+ microvesicles) are abnormally elevated in individuals who experienced acute exacerbations of COPD (AECOPD) and whether exosomes are associated with systemic inflammation

Ex vivo

Human

Exosomes (CD9 microvesicles) are elevated in COPD and AECOPD. Level of exosomes correlated with an increase in plasma CRP, sTNFR1 and IL-6, which are well-established markers of systemic inflammation and associated with COPD, with AECOPD group having the highest elevation when compared to sCOPD and healthy controls

Tokes-Fuzesi et al., 2018 [48]

Role of microparticles derived from monocytes, endothelial cells and platelets in the exacerbation of COPD

Measure EMPs and other cell-derived circulating MPs in stable and exacerbated COPD patients

Ex vivo

Human

Highly elevated MP levels were found in COPD patients compared to controls, and in particular, CD62E+, CD41+, CD42a+ and CD14+ MPs were significantly increased in exacerbated COPD versus stable COPD, indicative of endothelial activity and vascular injury in the lungs. CD62E+, CD42a+ and CD14+ MPs correlated inversely with FEV1/FVC