Poster Presentation – Gabrielle Grifno

ABSTRACT

Mosaic pattern: alveolus-level functional heterogeneity across lifespan and species

Gabrielle N. Grifno, Han Ali Kahvecioglu, Victoria Travnik, Robert LeBourdais, Rohin Banerji, Winita Wangsrikhun, Linzheng Shi, Suleyman B. Bozal, Heewon Suh, Athanasios Batgidis, Byungjun Kang, Abdulrahman Kobayter, Lauren Castle, Kathryn Regan, Feiyang Deng, Michael Vannini, Mohammad Rashidian, Liang Hao, Joseph P. Mizgerd, Worth Longest, Michael Hindle, W. Mark Saltzman, James P. Butler, Béla Suki, Hadi T. Nia.

Objectives: The distribution of inhaled aerosols (pollutants, pathogens, and therapeutics) is critical for respiratory health. Age-related changes in lung mechanics influence disease susceptibility and treatment efficacy, yet how aerosol deposition evolves from birth through aging remains unknown. Clinical imaging (CT, MRI) lacks singleaerosol resolution, and histology provides only static snapshots, limiting our ability to probe age-dependent differences in aerosol transport within the lung. We developed a transparent “crystal” ribcage (Banerji & Grifno, Nat. Methods, 2023) that enables whole-organ to single alveolus imaging of intact, ventilated mouse lungs during real-time aerosol delivery across the mouse lifespan.

Methods: Fluorescent aerosols (2–10 μm) were delivered, imaged, and tracked to quantify deposition and postdeposition transport under spontaneous breathing in vivo or during ex vivo mechanical ventilation in mouse lungs.

Results: Inhaled aerosols deposited in a spatially heterogeneous, deterministic “mosaic pattern,” consisting of high-deposition regions (“tiles”) separated by alveoli with negligible deposition (“bands”) (Fig. 1a-b). Sequential delivery of aerosols confirmed the reproducibility of this novel pattern in vivo and ex vivo, indicating that deterministic flow features (not stochastic events) govern deposition (Fig. 1c). In neonatal lungs, tiles and bands occupied similar areas, but with age, tile size increased while bands remained narrow (1–3 alveoli wide) (Fig. 1d). Post-deposition redistribution of liquid aerosols containing protein-sized tracers (70 kDa) was slower in agedlungs, revealing altered transport microdynamics in aging (Fig. 1e). Lastly, mosaic pattern indication was present in porcine and human lungs, meaning that alveolar heterogeneity persists in lung sizes comparable to humans and is not unique to mice (Fig. 1f-g).

Conclusions: We discovered a previously unrecognized, spatially heterogeneous mosaic pattern of aerosol deposition and diffusion that persists across species and the lifespan. This pattern exhibits age-dependent differences with implications for lung physiology, immune conditioning, disease vulnerability, and the development of age-specific inhaled therapeutics.