Determination of cell types and numbers during cardiac development in the neonatal and adult rat and mouse

Abstract

Cardiac fibroblasts, myocytes, endothelial cells, and vascular smooth muscle cells are the major cellular constituents of the heart. The aim of this study was to observe alterations in myocardial cell populations during early neonatal development in the adult animal and to observe any variations of the cardiac cell populations in different species, specifically, the rat and mouse. Whole hearts were isolated from either mice or rats during the neonatal and adult stages of development, and single cell suspensions were prepared via sequential collagenase digestion. Heterogeneous cell populations were immunolabeled for specific cell types and analyzed using fluorescence-activated cell sorting (FACS). In addition, the left ventricle, right ventricle, and septa were isolated, fixed, and sectioned for morphometric analyses. These same cardiac regions were also analyzed using FACS. We observed that the adult murine myocardium is composed of approximately 56% myocytes, 27% fibroblasts, 7% endothelial cells, and 10% vascular smooth muscle cells. Moreover, our morphometric and FACS data demonstrated similar percentages in the three regions examined. During murine neonatal cardiac development, we observed a marked increase in numbers of cardiac fibroblasts and a resultant decrease in percentages of myocytes in late neonatal development (day 15). Finally, FACS analyses of the rat heart during development displayed similar results in relation to increases in cardiac fibroblasts during development; however, cell populations in the rat differed markedly from those observed in the mouse. Taken together, these data enabled us to establish a homeostatic model for the myocardium that can be compared with genetic and cardiac disease models.

Fibroblast proliferation alters cardiac excitation conduction and contraction: a computational study

“…Other types of cells, such as those in vasculature and connective tissues, (Manabe et al, 2002), are not considered. Recent studies have revealed that fibroblasts, as one kind of connective tissue, are the most abundant cell type by number in cardiac tissues, comprising about 70% of all cells (Banerjee et al, 2007). Because of their small size, they make up only about 6% of the total cardiac volume (Rossi, 2001).…”

Are We There Yet? A Story About Cardiac Stem Cells

“…The mouse heart is composed of ~56% cardiomyocytes, 27% fibroblasts, 10% vascular smooth muscle cells and 7% endothelial cells (Banerjee et al, 2007). Most likely, several other cell types are hidden within these principal groups awaiting further characterization.…”

“…Rat hearts contain only 26.4% cardiomyocytes, a number that is similar to human beings. The major cell type in rat and human hearts is the fibroblast (62.6%) (Banerjee et al, 2007;Nag, 1980). If we look at the composition of cell types in the heart, rats appear to be rather similar to humans (Rubart & Field, 2006).…”

Efeitos dos corticoesteroides nas lesões por radiofrequência na coxa de ratos em diferentes faixas etárias

“…This happens, in this phase, because, in contrast with the adult muscle, the muscle and interstitial cells divide actively 14,15 . Our findings suggest that, in the pubescents, the passive growth predominates in relation to the cellular proliferation, while in the infants the two components prevail.…”