Biomedical Engineering Reference
In-Depth Information
HSC
G−CSF
CFU−S
(progenitor)
GM−CSF
TGF β
CFU−GEMM
SCF
bone
BFU−E
marrow
Epo
CFU−E
IL
proerythroblast
IGF1
basophilic erythroblast
polychromatophylic erythroblast
orthochromatic erythroblast
reticulocyte
(nuclear extrusion)
blood
erythrocyte
Fig. 2.4
Erythropoiesis (CFUs: colony-forming unit-spleen; CFUgemm: colony-forming unit-
granulocyte-erythroid-macrophage-megakaryocyte; BFUe: burst-forming unit-erythroid; CFUe:
colony-forming unit-erythoid). Many growth factors intervene, such as erythropoietin (Epo),
granulocyte-monocyte colony-stimulating factor (gmCSF or CSF2), granulocyte colony-
stimulating factor (gCSF or CSF3), stem cell factor (SCF), and insulin-like growth factor-1
(IGF1). Among interleukins, IL1, IL3, IL6, IL9, and IL11 are implicated in different stages of
erythropoiesis. Transforming growth factor-
β
(TGF
β
) inhibits the CFUgemm formation.
2.4.2.2
Erythropoietin
Erythropoietin (Epo) is a glycoprotein hormone synthesized mainly by the kidney
cortex stimulated by hypoxemia in the renal arteries and by the liver. It activates the
production of erythrocytes (Fig.
2.4
).
46
46
Erythropoietin (Epo) and its receptor (EpoR) are also synthesized by neoplastic cells and tumor
endothelial cells.
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