Abstract 204: Engineered Heart Tissue - A Novel Tool for Studying the Acute Ischemia Induced Changes in-vitro
Objective: Understanding the basic mechanisms and prevention of any disease pattern lies mainly on development of a successful experimental model. Recently, engineered heart tissue (EHT) has been demonstrated to be a useful tool in experimental transplantation. Here we demonstrate a novel function for the spontaneously contracting EHT as an experimental model in studying the acute ischemia induced changes in-vitro.
Method: EHT was constructed by mixing cardiomyocytes isolated from the neonatal rats with collagen and matrigel, and cultured in a ring shaped scaffold for 5 days. This was followed by mechanical stretching of the EHT for another 1 week under incubation. Fully developed EHT were subjected to hypoxia with 1% O2 for 6hrs after treating them with cell protective agents such as cyclosporine A (CsA) and acetylcholine (ACh).
Results: During culture EHT started to show spontaneous contractions that became more synchronous following mechanical stretching. This was confirmed by the increased expression of gap junctional protein connexin 43 and improved action potential recordings using an optical mapping system (Figure 1⇓⇓) after mechanical stretching. When subjected to hypoxic insult, EHT demonstrated loss of connexin 43 and degradation of cell survival Akt and antiapoptotic protein BCl-2 (p<0.05 versus normal) (Figure 2⇓), similar to that of an adult myocardium. In contrast, treating the EHT with CsA or ACh prevented this degradation.
Conclusion: Under hypoxic conditions, EHT responds similar to the adult myocardium, thus making them a promising material for the study of cardiac functions in-vitro.