Abstract Rationale Understanding lung-heart mechanobiology in health and disease requires simultaneous imaging access and control to ventilation and perfusion dynamics. In our previously developed crystal ribcage platform (Nature Methods 2023), the ex vivo lung is ventilated and perfused by mechanical pumps, which do not reproduce the physiological cardiopulmonary interactions driven by an intact, beating heart. Lung-only and heart-only preparations therefore fail to capture bidirectional mechanical and inflammatory coupling, limiting studies of ventilation-perfusion matching, pulmonary vascular mechanics, and systemic sequelae of lung or heart injury. Here, we present a novel heart-lung block extension of the crystal ribcage. By restoring physiological auto-perfusion of the heart while maintaining optical access via crystal ribcage, this platform enables paired interrogation of alveolar deformation, microvascular flow, and cardiopulmonary mechanical coupling under controlled ventilation and perfusion, expanding the scope of mechanobiology studies directly relevant to cardiopulmonary physiology and disease. Methods Murine heart-lung blocks were prepared under anesthesia with systemic anticoagulation. Following tracheal cannulation and initiation of mechanical ventilation, a median thoracotomy was performed, and animals were chilled in cold PBS. The inferior vena cava and aorta were catheterized, and both superior vena cavae were ligated. Perfusion was initiated retrograde through the aorta in a Langendorff-like mode to perfuse coronary vasculature. As spontaneous contractions emerged, flow transitioned gradually to anterograde, and the preparation was gently warmed to 37 °C to stabilize function. The perfusate consisted of a nutrient buffer supplemented with ∼20% packed bovine red blood cells, oxygenated through the ventilated, intact lung. Aortic pressure, aortic flow, venous pressure, tidal volume, and temperature were recorded continuously. Future experiments will mount the integrated heart-lung block in the crystal ribcage for ultra-fast confocal imaging in reporter mice, capturing real-time dynamics of cardiomyocyte and alveolar deformations during coordinated heart beating and lung ventilation and explore how these dynamics evolve with aging. Results During anterograde flow, heartbeats were evident from aortic pressure waveforms (∼200 bpm). Cardiac and pulmonary functions remained stable for over 2 hours, confirming feasibility of the combined heart-lung block. Conclusions The autoperfused heart-lung block restores physiologic pumping and pulmonary perfusion while maintaining optical access to alveolar and myocardial microstructure. This novel preparation addresses unmet needs of single-organ ex vivo models by enabling controlled studies of ventilation-perfusion coupling, pulmonary vascular mechanics, and bidirectional heart-lung interplay. Ongoing work will utilize spinning-disk confocal imaging to quantify cellular responses in both heart and lungs during injury, infection, and aging, linking organ-scale physiology to cellular mechanobiology. This abstract is funded by: DP2HL168562, Beckman Young Investigator Award, NSF CAREER Award, Hevolution/AFAR New Investigator Award.
Tsao et al. (Fri,) studied this question.