Ask AI: Describe the mechanisms via which mesenchymal stem cells are proposed to promote vascularisation upon implantation in vivo

The mechanisms by which mesenchymal stem cells (MSCs) are proposed to promote vascularisation upon implantation in vivo have not been fully elucidated. However, several mechanisms have been suggested. First, MSCs may promote angiogenesis, or the formation of new blood vessels, by secreting pro-angiogenic factors, such as vascular endothelial growth factor (VEGF). VEGF can interact with endothelial cells to promote the formation of new blood vessels. MSCs may also promote vascularisation by acting as a pre-vascular scaffold, providing a substrate for endothelial cell migration and proliferation. As MSCs grow and differentiate, they release extracellular matrix components, such as hyaluronic acid, which may promote the adhesion and migration of endothelial cells, contributing to the formation of new blood vessels. In addition, MSCs may induce vascularisation indirectly by modulating the immune system. MSCs have immunomodulatory properties, meaning they can modulate the inflammatory response and the activation of resident macrophages. This may reduce the expression of inflammatory factors, such as TNF-α, which can inhibit vascularisation. Finally, MSCs may promote vascularisation by differentiating into pericytes, which are important components of the microvasculature. Pericytes are specialised cells that line the walls of small blood vessels, and their presence is necessary for vascular stability and maturation.