A global leading cause of death is cardiovascular disease (CVD), and this is often linked to a number of abnormalities in the arterial system. Numerous clinical, in vivo, and in vitro studies are ongoing to better understand various forms of CVD and to find ways to combat it. Although studying cells of the cardiovascular system in vitro has led to many discoveries, it is a challenge to study explanted cells because they do not grow well and lose specificity. However, researchers found that a combination of two transcription factors, MYCN and SOX17, can induce and indeﬁnitely expand cultured human arterial endothelial cell precursors that are derived from CD34+ stem cells.
It is not uncommon to discover exciting and crucial knowledge by happenstance. Such is the case with this discovery of how to indefinitely expand the arterial cell precursors. In this process, the researchers revealed key information that can help understand how arterial endothelial cell growth is regulated. They found a “good cell-bad cell” scenario when growing the endothelial cells over generations. When the hematopoietic CD34+ stem cells were transfected with the two transcription factors and grown, two types of endothelial cells expanded.
One cell type observed was the healthy elongated-shaped endothelial cells that grow in single layers and are characteristic of actual arterial cell morphology. The other type was the star-shape mesenchymal cells that can build up in an artery, stack on one another, and cause arterial thickening that is linked to arteriosclerosis. The development of the mesenchymal cells is referred to as endothelial to mesenchymal transition and is a key risk factor in cardiovascular disease development.
This use of CD34+ stems cells derived from cord blood or bone marrow to obtain endothelial cells capable of indefinite proliferation in culture is a major contribution to cardiovascular science and medicine. The ability to grow and study healthy and disease-related cell types in culture provides an excellent means to study the mechanisms associated with various forms of CVD. Armed with the information that can subsequently become available can potentially provide novel and powerful tools for discovering effective preventive measures and drug treatments for CVD.