D96-02 Development of Vivo-µOct Platform for In Vivo Evaluation of Mucociliary Disorders and Drug Discovery in Respiratory Diseases: Applications in COPD and Aging

Abstract Rationale Mucociliary disorder (MCD) plays a crucial role in the pathogenesis of various respiratory diseases, including chronic obstructive pulmonary disease (COPD). Airway mucus plugs are independently associated with impaired lung function, emphysema severity, and mortality. However, the lack of in vivo MCD evaluation techniques has hindered the understanding of spatiotemporal mucociliary dynamics throughout disease development and drug discovery. Methods Through integrating novel airway-immobilization protocol, axial resolution enhancement, motion-artifact compensation algorithms and automated interactive quantification software, we developed Vivo-µOCT platform allowing in vivo, high-resolution, real-time and quantitative imaging of airway MCDs in animals and COPD patient-derived organoids, including airway epithelial structure, ciliary activity, mucosal liquid dynamics, particle tracking and submucosal gland function. Results Vivo-µOCT sensitively detects MCDs induced by temperature, energy, pharmacological and genetic perturbations in vivo. Repeated measurements could be performed in the same mouse, in 2 weeks interval, demonstrating the feasibility of longitudinal assessment. In 16 months’ tracking of COPD progression, MCDs appear earlier than pulmonary function decline and alveolar destruction. Short-term smoking induced transient increase of ciliary beat frequency (CBF), while long-term smoking led to continuous decline in CBF and increased secretion of submucosal glands and airway surface liquid (ASL) depth. Consistently, MCD was observed in pre-COPD patients with normal lung function. In contrast, physiological aging is accompanied by slow MCC deterioration in 22 months’ tracking period, with significant CBF decline found after 12 months. A specific group of ciliary structural, mobility, metabolism and inflammatory genes were dysregulated during aging and COPD based on single cell RNA sequencing analysis. In vivo pharmacological intervention with nebulized salmeterol effectively restored CBF to normal levels in COPD mice, while MCT and particle clearance showed partial improvement, which is confirmed by treatment of COPD patient-derived airway organoids. Smoking cessation modestly ameliorated MCC function, and combined therapy with salmeterol achieved more pronounced and sustained benefits. Notably, MCD was not fully reversible, highlighting persistent mucus abnormalities and airway remodeling despite current treatment options. Conclusions Vivo-µOCT is a powerful platform for real-time, quantitative in vivo evaluation of airway MCDs. MCDs are the early sensitive indicators of disease onset and progression in COPD. MCDs develop slower in aging compared to COPD, partially explained by dysregulation of genes related to ciliary structure and mobility. Therapeutic interventions including smoking cessation and salmeterol can partially restore MCC but fail to fully normalize MCT, highlighting the need for early, multimodal treatment strategies targeting MCDs. This abstract is funded by: Noncommunicable Chronic Diseases-National Science and Technology Major Project (2024ZD0528400); National Natural Science Foundation of China (82270001, 22HAA00617); National Key R&D Program of China (2024YFA1108900)