Vascular stem cells, new culprits uncovered
Recent studies from our lab highlight the functional significance of pathologic neovascularization derived from vascular stem/progenitor cells as an important mechanism of formation of new blood vessels in adults, in the setting of chronic liver disease, and identifies these stem cells as potential new therapeutic targets. Thus, we have demonstrated the existence in the vascular wall of adult mesenteric blood vessels of a distinctive population of vascular stem/progenitor cells. These cells display some of the most widely accepted criteria for stem cell recognition, including quiescence and slow-cycling properties, high proliferative potentiality, capability of growing as cellular spheres in suspension culture, expression of specific biomarkers of stem cells, and the ability to self-renew and generate daughter cells in response to liver disease induction. This vascular stem cell progeny is able to differentiate into endothelial and smooth muscle cell lineages, and readily contribute physically and functionally to neovascularization in vivo during chronic liver disease. Hence, chronic liver disease-associated abnormal neovascularization might conceivably be a heterogeneous process, arising through a combination of both neoangiogenesis and neovasculogenesis. Accordingly, therapeutic targeting of both vascular stem cell-derived neovascularization (vasculogenesis) and new vessel growth mechanisms that utilize non-stem cell constituents (angiogenesis) may effectively block abnormal neovessel formation and improve antiangiogenic therapeutics (Read More).