Living myocardial slices as a model for testing cardiac pro-reparative gene therapies

Available models currently adopted for preclinical studies in the cardiovascular field either fail to recapitulate human cardiac physiology or are extremely expensive and time-consuming. Translational research would greatly benefit from the development of novel models that reflect the native mature phenotype of the human heart while being cost and time effective. Living myocardial slices (LMSs) have emerged as a novel, powerful ex vivo tool for translational research. Although the number of studies adopting LMSs is rapidly increasing, this model remains largely under-characterized. In this study, we make use of LMSs and compare them to a murine model to deliver the cardioprotective factor zinc finger E box-binding homeobox 2 (ZEB2), a transcription factor known to exert cardioprotective effects after ischemic injury and promote the secretion of pro-angiogenetic factors thymosin beta-4 (TMSB4) and prothymosin alpha (PTMA). Our data show that viral-mediated delivery of these factors induced similar cardiomyocyte gene expression changes in LMS and mouse models. We also show that the delivery of these pro-angiogenic factors enhances an angiogenic response in both models, indicating that LMSs are a suitable alternative to mice for studying the effects of gene transfer in various cardiac cell types.