Consistent with the data for all pulmonary arteries, both COPD and COPD-PH individuals had significantly increased SMA abundance, particularly in the small pulmonary arteries (p < 0.0001 and 0.0008, respectively) and the microvasculature (p < 0.0001 and 0.006, respectively) (Fig. 1D, E). This evidence concerns the gene SMN1 and chronic obstructive pulmonary disease.