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. Author manuscript; available in PMC: 2010 Jan 1.
Published in final edited form as: Biotechnol Prog. 2009 Jan–Feb;25(1):32–42. doi: 10.1002/btpr.128

Figure 1. Oxygen tensions in stem cell microenvironments.

Figure 1

Embryonic stem cells and adult bone marrow-derived stem cells reside in low oxygen environments. (A) Embryonic stem cells are derived from the inner cell mass of early stage blastocytsts and maintain a totipotent state that forms ectoderm, endoderm, and mesoderm. The intrauterine environment in which the embryonic stem cells growth and development occur has an oxygen tension ranging from 1–5% through the first trimester. (B) Oxygen tension in bone marrow is well below ambient oxygen environment in the range of 3–7% O2 with oxygen concentrations decreasing with distance away from sinuses. Recent in vivo studies provided direct experimental evidence that HSCs are distributed predominantly at the lowest end of an oxygen gradient within the bone marrow and away from sinuses.