Resident microglia rather than peripheral macrophages promote vascularization in XXXX and are source of alternative pro-angiogenic factors.

@entity1313 @entity5 @entity7 @entity11 @entity6980 @entity10149 @entity7416 @entity463
UNASSIGNED: Myeloid cells are an essential part of the @entity463 microenvironment. However, in @entity1313 the function of these immune cells is not sufficiently clarified. In our study, we investigated differential pro-angiogenic activities of resident microglia and peripheral macrophages and their impact on @entity11 vascularization and progression. Our data demonstrate stable accumulation of microglia/macrophages during @entity5 growth. These cells often interact with @entity5 blood vessels correlating with @entity6980 . Here, we identified resident microglia as well as peripheral macrophages as part of the perivascular niche, primarily contacting endothelial cells. We found overexpression of a variety of pro-angiogenic molecules within freshly isolated microglia/macrophages from @entity11 . @entity10149 , until now a poorly described chemokine, was strongly up-regulated and showed better angiogenic activity than @entity7 in vitro. Blocking the @entity10149 - @entity7416 signaling pathway resulted in considerably diminished @entity11 sizes. Additionally, the importance of microglia/macrophages in @entity5 angiogenesis was confirmed by depletion of these cells in vivo. Vessel density decreased by 50  % leading to significantly smaller @entity5 volumes. Remarkably, selective reduction of resident microglia affected tumoral vessel count comparable to ablation of the whole myeloid cell fraction. These results provide evidence that resident microglia are the crucial modulatory cell population playing a central role in regulation of vascular homeostasis and angiogenesis in @entity1313 . Thus, resident microglia represent an alternative source of pro-angiogenic growth factors and cytokines.
