SLC22A5 and chronic obstructive pulmonary disease: Really, an immunohistochemistry analysis recently performed in lung tissues from healthy and COPD patients detects OCTN2 on the apical and lateral side of the epithelial cells in the bronchial region and in cells lining the bronchioles [33]; similarly, the transporter has been shown on the apical surface of ALI Calu-3 layers [15].