Effect of mycobacterial lipids on surface properties of Curosurf™: Implications for lung surfactant dysfunction in tuberculosis

In this study, the effect of mycobacterial lipids on the surface activity of lung surfactant was evaluated. Mycolic acid and cord factor, the most abundant surface active lipids of the mycobacterial cell wall when combined with Curosurf™ led to alteration of its surface properties. Addition of graded amounts of mycolic acid increased the minimum surface tension of Curosurf™ monolayers from <10 mN/m to ∼20–27 mN/m. Presence of mycolic acid also slowed the rate of Curosurf™ adsorption. Similarly, presence of cord factor increased the minimum surface tension achieved by Curosurf™ to ∼16–27 mN/m. AFM imaging revealed presence of aggregates on addition of mycobacterial lipids to Curosurf™ monolayers. Results of this study show that mycolic acid and cord factor can biophysically inactivate porcine lung surfactant extract (Curosurf™). This suggests that biophysical inhibition of lung surfactant is possible in vivo in pulmonary tuberculosis which could aggravate areas of alveolar atelectasis.