In contrast to adult mammals, zebrafish have the capacity to regenerate their hearts upon several types of injury. In the laboratory, we use cryoinjury, to induce a cardiac tissue damage with the aim to mimic the consequences of tissue loss upon myocardial infarction González-Rosa and Mercader, 2012).
Upon eliminating up to ¼ of the cardiac ventricle zebrafish are able to regenerate the damaged myocardium and recover cardiac function (González-Rosa et al., 2014).
Massive collagen depositions precede the process of cardiac regeneration, revealing that, in contrast to mammals, cardiac fibrosis is reversible in the zebrafish and occurs as an intermediate step during regeneration (González-Rosa et al., 2011).
We are interested in understanding the mechanisms through with in the zebrafish, the fibrotic tissue, including extracellular matrix and myofibroblast regress, as this might have implications for the design of antifibrotic strategies in mammals. We are also interested in understanding which are the cells contributing to the fibrotic response.
The epicardium, the outer layer covering the myocardium contains precursors contributing to the fibrotic response observed after cryoinjuring the zebrafish heart (González-Rosa et al., 2012).
We are interested in analysing the mechanisms of epicardium reestablishment as well as the influence of this layer during the regeneration process.
We are also interested in analysing how the epicardium forms during embryonic development. The epicardium derived from the proepicardium, a cell cluster emerging at the inflow region of the forming heart tube (Peralta et al., 2014).
Using live imaging in zebrafish embryos we are studying the mechanisms through which proepicardial cells are emerging from the pericardial wall and attach to the myocardium. We found that proepicardial cells detach from the pericardial wall and are advected around the cardiac ventricle, and subsequently attach to its surface (Peralta et al., 2013).
We also found that this process is dependent on the heartbeat. Our current effort is dedicated to understand the underlying mechanosensory pathways as well as the role of extracellular and secreted molecules controlling proepicardium and epicardium formation.