Key Endothelial Signals Required for Hematopoietic Recovery

Wilmot Cancer Center and Endocrine Division, University of Rochester School of Medicine, 601 Elmwood Avenue, Box 693, Rochester, NY 14642, USA.
Cell stem cell (Impact Factor: 22.27). 04/2009; 4(3):187-8. DOI: 10.1016/j.stem.2009.02.005
Source: PubMed


In this issue of Cell Stem Cell, Hooper et al. (2009) use a combination of immunohistochemistry and flow cytometry to characterize the bone marrow vasculature both before and after injury. The authors demonstrate that recovery of normal hematopoiesis after myelosuppressive insult is dependent upon endothelial VEGFR2.

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    • "Many groups have helped to characterise the bone marrow stem cell niche(s) (Adams et al. 2007, Frisch et al. 2008, Porter and Calvi 2008, Raymond et al. 2009) and, in terms of regulation, have shown that it occurs through cells within the bone marrow microenvironment, an environment that includes, for example, the osteoblasts (Calvi et al. 2003), osteoclasts (Kollet et al. 2006), and endothelial cells (Porter and Calvi 2009), and is likely maintained through cell-cell and cell-extracellular matrix interactions. With respect to radiation injury specifically, some investigators have shown that the bone marrow stem cell niche is relatively hypoxic (Parmar et al. 2007) and since the stem cells appear to exist in a quiescent or very slowly cycling state (Harrison and Astle 1982, Schaniel and Moore 2009) they are therefore, relatively radio-resistant. "
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