Colony-stimulating factor-1 expression in the human fetus and newborn.

Abstract

Colony-stimulating factor-1 (CSF-1) is a hematopoietic growth factor that regulates the survival, proliferation, and differentiation of mononuclear phagocytes. Because this cellular compartment undergoes major changes during fetal and neonatal life, we examined concurrent CSF-1 expression during human development. While levels increased dramatically after full-term birth, CSF-1 concentrations steadily declined in the preterm circulation from 2.7 to 1.9 times adult values as gestational age increased. CSF-1 was already detectable at 10 weeks gestation in spleen, intestine, lung, kidney, heart, and liver in order of decreasing concentration, but a positive correlation with gestational age was seen only in lung and intestine. Although a 4.4-kb CSF-1 mRNA was detectable in all tissues at all gestational ages, increased expression with advancing gestational age was observed in lung and kidney, whereas a rise and fall was observed in spleen. We conclude that CSF-1 concentration in the human circulation is developmentally regulated and that its expression in fetal tissues is compatible with its role in regulating the development of tissue mononuclear phagocytes.