Assessment of Ex Vivo Murine Biventricular Function in a Langendorff Model

Abstract

Primary graft dysfunction (PGD) remains the leading cause of early death following heart transplantation. Prolonged ischemic time during cold preservation is an important risk factor for PGD, and reliable evaluation of cardiac function is essential to study the functional responses of the donor heart after cold preservation. The accompanying video describes a technique to assess murine right and left ventricular function using ex vivo perfusion based in a Langendorff model after cold preservation for different durations. In brief, the heart is isolated and stored in a cold histidine-tryptophan-ketoglutarate (HTK) solution. Then, the heart is perfused with a Kreb buffer in a Langendorff model for 60 min. A silicone balloon is inserted into the left and right ventricle, and cardiac functional parameters are recorded (dP/dt, pressure-volume relationships). This protocol allows the reliable evaluation of cardiac function after different heart preservation protocols. Importantly, this technique allows the study of cardiac preservation responses specifically in native cardiac cells. The use of very small murine hearts allows access to an enormous array of transgenic mice to investigate the mechanisms of PGD.

Figure 1:. Mounting and cannulation of the mouse heart.

(A) Overall setup of the perfusion setup. 1. Perfusion reservoir. 2. Oxygenation chamber. 3. Air trap chamber. 4. Heart chamber. 5. Value switch for constant flow and pressure. 6 and 7. Oxygen inflow. (B) Cannulated hearts with the RV in the front. (C) Position of the RV to cut for opening its cavity. (D) Tap the balloon tube with the cannula. Abbreviation: RV = right ventricle.

Figure 2:. Comparing the function of the LV versus RV.

(A) Tracing record of max and min dP/dt in the RV and LV in the donor heart with 0 h of storage. (B) The record of max and min dP/dt in the RV and LV in the donor heart with 8 h of storage. (C,D) Details of dP/dt, LV pressure, heart rate, and perfusion pressure in the LV and RV at 0 h and 8 h. Abbreviations: RV = right ventricle; LV = left ventricle; dP/dt = pressure-time relationship.

Figure 3:. Comparing the function of the LV versus RV after storage and perfusion.

(A) Systolic and diastolic pressure of the LV and RV after 0 h and 8 h of storage. (B) Max dP/dt and (C) Min dP/dt of the LV and RV after perfusion with 0 h and 8 h of storage. This figure is from Lei et al..