Table 4.

Approaches to cardiogenic small molecule discovery

Approaches	Method	Hurdles	Advantages
In silico	Molecular docking of small molecules to active site of target protein	Requires crystal structure of targeted protein	A large library of druggable small molecules may be computationally screened for in vitro verification
In vitro	Screening of small molecules against expressed target protein	Requires development of in vitro assay	A high throughput screening may be designed
Ex vivo	Screening of small molecules inducing neonatal rat CM proliferation	Neonatal proliferating CMs are used instead of adult CMs	Flow cytometric or fluorescent microscopy techniques may be used to determine proliferating CMs using markers such as Nkx2.5 and Phospho-H3
In vivo	Injection of small molecule into mouse	Costly. Requires use of a large number of animals	Provides in vivo stimulation effect of injected small molecules toward CM renewal

CM - cardiomyocyte