HIF-1α level, evaluated via ELISA, was significantly lower in HS-EVs (2.1 pg/ml, SEM = 1.5 pg/ml) than in COPD-EVs (7.5 pg/ml, SEM = 2.0 pg/ml) (*p = 0.03) (Fig. 4B). This evidence concerns the gene HIF1A and chronic obstructive pulmonary disease.