Rapid 3D visualization of airway remodeling in healthy and asthmatic lung biopsies using higher harmonic generation microscopy

<bold>Introduction:</bold> Asthma is characterized by airway remodeling, including an increase in airway smooth muscle (ASM), changes in the extracellular matrix (ECM) and epithelium, and assessment of these can contribute to the diagnosis of asthma. Higher harmonic generation microscopy (HHGM) is a fast, label-free imaging technique that combines third harmonic generation (THG), second harmonic generation (SHG), and two-photon excited autofluorescence (2PEF), to visualize cells, collagen and elastin, respectively, in 3D in unprocessed tissue. <bold>Hypothesis & Aim:</bold> We hypothesize that assessment of the epithelium and ECM in HHGM-images is a faster and less demanding method to provide information on airway remodeling. In this proof of principle study, we tested this hypothesis by investigating differences in epithelium and ECM between healthy volunteers and asthma patients. <bold>Methods & Results:</bold> Bronchoscopically obtained airway biopsies from asthma patients and healthy volunteers were immediately imaged by HHGM without further processing steps. In a few minutes 2D overview scans were made for each biopsy and Z-stacks from regions of interest, to characterize the airway wall layers in 3D. Changes in epithelium and ECM were found. <bold>Conclusion:</bold> Assessment of the HHGM visualized epithelium and ECM in the airway biopsies has potential to give new insights into airway remodeling in asthma. <fig><object-id>erj;64/suppl_68/PA5248/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>