Modeling cardiac injury using human cardiac slices to test therapeutic approaches for cardiac regeneration and repair

Abstract Background Due to limited regenerative capacity of the adult human heart, myocardial infarction causes irreversible damage by inducing the death of cardiomyocytes and the formation of a fibrotic scar. These remodeling mechanisms cause loss of contractility and eventually heart failure ensues in a significant proportion of patients. Purpose There is a need for a reliable model that can replicate the adult cardiac pathophysiology in order to test treatments against cardiac remodeling. Here, we developed a cardiac tissue culture model that can simulate in vitro the molecular changes occurring after cardiac injury using human cultured cardiac slices. Methods We obtained cardiac slices by sectioning ventricular myocardium from the surgical waste material of adult patients undergoing valve surgery or Morrow myectomy. Cardiac slices were cultured at a liquid-air interface and were viable up to 7 days of culture, even in the absence of stimulation. During this time cardiac slices underwent mechanical and chemical treatments to induce ischemia and/or local injury. Results We found that following these treatments we were able to simulate cardiac remodeling in terms of cardiomyocyte death, activation of cardiac fibroblasts and induction of inflammation and oxidative stress. Following small molecule screening, we discovered that addition of compounds with anti-inflammatory properties (e.g. dexamethasone) or targeting the TGF-β pathway (e.g. SB-431542) into our culture medium helped in preserving the microscopic structure of the slices. Additionally, we found that treatment with these compounds protected cardiac slices against remodeling following ischemic injury. Conclusions In conclusion, our model can emulate cardiac pathophysiology in culture, providing us a reliable platform to test therapies for cardiac regeneration and repair in an adult, multicellular, 3-D environment.