Abstract 347: The Success of Humanizing Miniature Hearts is the Right Cannulation

The development of humanized miniature organs through decellularization of rodent organs and recellularization with human cells will provide higher quality translational evidence for in vitro models from animal to human within basic research and pharmacological applications. Here, we have focused on the preservation of the circulation network within rat hearts by cannulating the superior vena cava (SVC), ascending aorta (A), pulmonary vein (PV), and pulmonary artery (PA) (deemed 4-Flow). Compared to the conventional Langendorff, the 4-Flow cannulation is superior by allowing control of both atria and ventricles for non-invasive mechanical stimulation and most advantageous is access to both the coronary arteries and cardiac veins. Hence, the objectives are to thoroughly recellularize the heart and to conduct ventricular mechanical stimulation. Controlled perfusion was conducted with inflow via the SVC and A, and outflow via PV and PA. The resin cast of a decellularized heart in Figure 1A demonstrates that the retrograde flow in addition to antegrade flow through both coronary vascular networks permit efficient whole heart perfusion of solutions, cells, and factors. Multiphoton microscopy (1B) reveals that cells are perfused to capillaries and tissues but more so with enzymatic treatment (1C-D). All of the valves’ functionality are maintained, hence, mechanical stimulation of the left ventricle is possible via perfusion through the PV to expand the left chamber until the aortic valve opens to relieve the pressure (1E-F). Consequently, a 4-Flow humanized miniature heart is the complex in vitro model that will revolutionize the translation into patient studies.