In mice, hematopoietic cells home to bone marrow from fetal liver prenatally. To elucidate mechanisms underlying homing, we performed immunohistochemistry with the hematopoietic cell marker c-Kit, and observed c-Kit(+) cells localized inside muscle surrounding bone after 14.5 days post coitum. Flow cytometric analysis showed that CD45(+) c-Kit(+) hematopoietic cells were more abundant in muscle...

Human mesenchymal stem/progenitor cells (MSCs) have been identified in adult bone marrow, but little is known about their presence during fetal life. MSCs were isolated and characterized in first-trimester fetal blood, liver, and bone marrow. When 10(6) fetal blood nucleated cells (median gestational age, 10(+2) weeks [10 weeks, 2 days]) were cultured in 10% fetal bovine serum, the mean number ...

The liver can regenerate itself through the progenitor cells it harbors. Here we demonstrate isolation of epithelial progenitor/stem cells from the fetal human liver, which contains a large number of hepatoblasts. Progenitor liver cells displayed clonogenic capacity, expressed genes observed in hepatocytes, bile duct cells and oval cells, and incorporated genes transferred by adenoviral or lent...

We report the establishment and characterization of immortalized human fetal liver progenitor cells by expression of the Simian virus 40 large T (SV40 LT) antigen. Well-characterized cells at various passages were transplanted into nude mice with acute liver injury and tested for functional capacity. The SV40LT antigen-immortalized fetal liver cells showed a morphology similar to primary cells....

The ontogeny of cells containing the enzyme terminal deoxynucleotidyl transferase (TdT) in human fetal liver, bone marrow, and thymus has been studied using a highly specific antiserum to TdT together with monoclonal antiprecursor cell antibodies in double and triple marker immunofluorescence. TdT+ cells were first observed in fetal liver at 12 wk of gestation and accounted for 55% of the lymph...

Much controversy surrounds the identity and origin of human hepatic stem and progenitor cells in part because of a lack of small animal models in which the developmental potential of isolated candidate cell populations can be functionally evaluated. We show here that adoptive transfer of CD34(+) cells from human fetal liver into sublethally irradiated NOD-SCID Il2rg(-/-) (NSG) mice leads to an ...

Cited2 (cAMP-responsive elementbinding protein [CBP]/p300-interacting transactivators with glutamic acid [E] and aspartic acid [D]–rich tail 2) is a newly identified transcriptional modulator. Knockout of the Cited2 gene results in embryonic lethality with embryos manifesting heart and neural tube defects. Cited2 / fetal liver displayed significant reduction in the numbers of Lin cKit Sca-1 cel...

Polycomb-group (PcG) proteins are essential regulators of hematopoietic stem cells (HSCs). In contrast to Bmi1, a component of Polycomb repressive complex 1 (PRC1), the role of PRC2 and its components in hematopoiesis remains elusive. Here we show that Ezh2, a core component of PRC2, is essential for fetal, but not adult, HSCs. Ezh2-deficient embryos died of anemia because of insufficient expan...

Introduction Hematopoiesis in mouse fetal liver starts at 10 days of gestation and begins to decline after 15 days of gestation [1]. During postnatal hematopoietic involution, hepatocyte volume rapidly increases, and four types of specialized junctions; i.e., adherens junctions, desmosomes, tight junctions and gap junctions, appear to be fully developed in liver cells [2]. Neonatal livers exami...

BACKGROUND AND OBJECTIVES We previously found that human fetal lung is a rich source of mesenchymal stem cells (MSC). Here we characterize and analyze the frequency and function of MSC in other second-trimester fetal tissues. DESIGN AND METHODS Single cell suspensions of fetal bone marrow (BM), liver, lung, and spleen were made and analyzed by flow cytometry for the expression of CD90, CD105,...