(HealthDay News) – Vascular remodeling and diseases such as atherosclerosis may be traced back to differentiation of a newly discovered vascular stem cell rather than de-differentiation of smooth muscle cells.
To test the theory that vascular diseases result from de-differentiation of smooth muscle cells, Zhenyu Tang, from the University of California in Berkeley, and colleagues isolated cells from the tunica media of blood vessel walls.
The researchers identified a new type of stem cell in the blood vessel wall. These multipotent vascular stem cells were cloneable; had telomerase activity; and expressed markers such as Sox17, Sox10, S100β, and neural filament-medium polypeptide. They were able to differentiate into neural and mesenchymal stem cell-like cells, which subsequently differentiated into smooth muscle cells. Lineage tracing showed that these stem cells did not arise from the de-differentiation of mature smooth muscle cells. In response to vascular injuries, multipotent vascular stem cells became proliferative and contributed to vascular remodeling and neointimal hyperplasia by differentiation into smooth muscle cells and chondrogenic cells. Further investigation showed that multipotent vascular stem cells were also present in human carotid arteries.
“This study supports a new hypothesis that multipotent vascular stem cell activation and differentiation, instead of smooth muscle cell de-differentiation, results in the proliferative and synthetic cells in the vascular wall, and that the aberrant activation and differentiation of multipotent vascular stem cells may play an important role in the development of vascular diseases,” Tang and colleagues conclude.