The Gut–Lung Axis: What’s below the Diaphragm Is Also Important

One limitation in this study is that ALI from ZnONP exposure impacts a narrowly defined population, and the protective role of propionic acid in other models is unknown. Another important limitation to consider is that the lung microbiota were likely affected by antibiotics in this study. There is accumulating evidence in the literature that implicates the importance of lung microbiota in clinical outcomes in acute and chronic lung diseases. How antibiotics influenced lung microbiota in this model was not assessed. Nevertheless, this study adds novel insights to an ever-growing body of literature around the gut–lung axis, highlighting the importance of the gut in lung health.