Distribution of granulocyte colony-stimulating factor (G-CSF) and G-CSF-receptor mRNA and protein in the human fetus

Granulocyte colony-stimulating factor (G-CSF) promotes neutrophil prolifera tion, differentiation, and survival. It acts by binding to specific cell-su rface receptors (G-CSF-R), which are expressed on cells of granulocytic lin eage, human endothelial cells, and placenta. It has been postulated that th e administration of recombinant G-CSF (rG-CSF) to preterm neonates might be useful in treating infections or in reducing nosocomial infections. Wherea s it is known that G-CSF and G-CSF-R are present in the developing fetal bo ne marrow and liver, no information is available as to the existence or dis tribution of nonhematopoietic G-CSF-R in other tissues of the developing hu man fetus. We hypothesized that G-CSF and its receptor might be expressed i n various fetal tissues, as has been shown for other growth factors such as erythropoietin and fibroblast growth factor. Therefore, we studied the ana tomical distribution of mRNA-encoding G-CSF and G-CSF-R, using RT-PCR and i n situ RT-PCR in a variety of human fetal tissues ranging from 8 to 24 week s postconception. The cellular distributions of the corresponding proteins were determined by immunohistochemistry. Both G-CSF and G-CSF-R were presen t in nearly every organ and tissue examined, but in discrete cellular local izations. G-CSF-R in kidney and intestine underwent changes in anatomical d istribution with fetal development. These results indicate that G-CSF and G -CSF-R have wide anatomical expression in the developing human fetus.