The group of Fysikopoulos et al. (2020) established a mouse model of emphysema by treatment with elastase, and after pharmacological inhibition of iNOS, it demonstrated a partial regeneration of the parenchyma, so there is a relationship between increased expression of the enzyme and the appearance of emphysema, although it would not be the only cause. The gene discussed is NOS2; the disease is pulmonary emphysema.