New Methods in Cardiovascular Biology A Cell-Based Phenotypic Assay to Identify Cardioprotective Agents

Rationale: Tissue ischemia/reperfusion (IR) injury underlies several leading causes of death such as heart-attack and stroke. The lack of clinical therapies for IR injury may be partly due to the difficulty of adapting IR injury models to high-throughput screening (HTS). Objective: To develop a model of IR injury that is both physiologically relevant and amenable to HTS. Methods and Results: A microplate-based respirometry apparatus was used. Controlling gas flow in the plate head space, coupled with the instrument’s mechanical systems, yielded a 24-well model of IR injury in which H9c2 cardiomyocytes were transiently trapped in a small volume, rendering them ischemic. After initial validation with known protective molecules, the model was used to screen a 2000-molecule library, with post-IR cell death as an end point. PO2 and pH monitoring in each well also afforded metabolic data. Ten protective, detrimental, and inert molecules from the screen were subsequently tested in a Langendorff-perfused heart model of IR injury, revealing strong correlations between the screening end point and both recovery of cardiac function (negative, r20.66) and infarct size (positive, r20.62). Relationships between the effects of added molecules on cellular bioenergetics and protection against IR injury were also studied. Conclusions: This novel cell-based assay can predict either protective or detrimental effects on IR injury in the intact heart. Its application may help identify therapeutic or harmful molecules. (Circ Res. 2012;110:00-00.