On The Functional Dynamics of Alveolar and Ductal Growth in The Adolescent Lung

Abstract During adolescence, the lungs expand while alveoli increase greatly in number. A precise and deep understanding of the biological processes responsible for the many fold increase in alveoli during adolescence could form the foundation for novel treatments to reoptimize lung function after disease or injury. Herein we provide a unique insight into the alveolar growth in the mouse lung during first postnatal 4 weeks herein described as the adolescence phase. Using 3-Dimensionnal (3D) high-resolution large field of view optical imaging coupled with qualitative and quantitative analysis, we suggest the bulk of alveolarization during adolescent lung growth occurs while the surface to volume of the acinar volume remains constant. The most distal 10 or more bifurcations within the acinar saccular region, comprised of small ducts and alveoli, are of similar scale. We explored the connections between the growth of lung and it’s structural and functional parameters, by comparing the correlations between alveolar size, surface area of gas exchange regions, breathing rate, metabolic rate, and oxygen demand across mammalian species which exhibit widely divergent body sizes.