Figure 3

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Distinct populations of stem cells occupy microenvironments that contain different O2 levels

As described in the main text, some stem cells (such as those in the endosteal bone marrow compartment) occupy extremely low O2 microenvironments (less than 0.5% O2) as shown in (A). Other stem cells (as those described as perivascular SLAM+ (for Signalling Lymphocyte Activation Molecule) stem cells can occupy relatively well-oxygenated environments as they are in close proximity to blood vessel endothelial cells (B). However, it should be noted that although stem cells can be perivascular, the vessels might be associated with venous structures and therefore be relatively hypoxic.

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