Concepts of implantation physiology developed on the basis of previous work postulate that embryo implantation is initiated when trophoblast invasiveness coincides with astate of 'receptivity' of the endometrium, the latter being controlled by steroid hormones. However, neither trophoblast invasiveness nor endometrial receptivity are well understood in terms of their cell biological basis: a ro...

The trophoblast giant cell lineage is characterized by endoreduplication and expression of members of the PRL gene family. This report describes the functional consequences following in vitro manipulation of a rat trophoblast cell line, termed Rcho-1. Rcho-1 cells can be cultured under conditions that promote proliferation or differentiation. Proliferation is maintained by culturing the cells i...

Remodeling of the uterine spiral arteries during pregnancy transforms them from high to low resistance vessels that lack vasoconstrictive properties. This process is essential to meet the demand for increased blood flow imposed by the growing fetus. Loss of endothelial and smooth muscle cells (SMC) is evident in remodeled arteries but the mechanisms underlying this transformation remain unknown...

Development of human placenta involves the invasion of trophoblast cells from anchoring villi into the maternal decidua. Placental transcription factor GCM1 regulates trophoblast cell invasion via transcriptional activation of HtrA4 gene, which encodes a serine protease enzyme. The GATA3 transcription factor regulates trophoblast cell differentiation and is highly expressed in invasive murine t...

Cleavage and blastocyst formation in the mammal are characterized by precocious differentiation of the trophoblast, a population of cells which are specialized for functions related to the formation of an intimate physiological interrelationship between embryo and mother, as characteristic for these secondarily alecithal eggs: 1. transport of fluids, nutrients and metabolites; 2. hormone produc...

The mouse blastocyst stage covers approximately 2 days. During this period, embryonic development advances through four ultrastructurally distinct substages. Specific ultrastructural characteristics, such as changes in cell shape and/or the distribution of intracellular organelles, may be used to characterize the various cell types from each other at each substage (e.g. trophoblast from inner c...

Epithelial barrier integrity is dependent on progenitor cells that either divide to replenish themselves or differentiate into a specialized epithelium. This paradigm exists in human placenta, where cytotrophoblast cells either propagate or undergo a unique differentiation program: fusion into an overlying syncytiotrophoblast. Syncytiotrophoblast is the primary barrier regulating the exchange o...

Heparin is used clinically for the prevention of pregnancy complications associated with prothrombotic disorders, especially antiphospholipid antibody syndrome. Recent studies have suggested that heparin may exert direct effects on placental trophoblast, independently of its anticoagulant activity. We now demonstrate that heparin abrogates apoptosis of primary first trimester villous trophoblas...

Women with anticardiolipin antibodies (ACLA) are at increased risk for fetal loss. One potential explanation for this outcome is that sera from these individuals contain antibodies reactive with trophoblast cells, which are involved in the establishment of the uteroplacental vasculature and maintenance of placental blood fluidity. To examine this hypothesis, we compared the incidence of trophob...

To investigate the possible role of nitric oxide (NO) produced locally or intramurally in the quiescence of the pregnant myometrium, nitric oxide synthase (NOS) activity was measured in samples from first trimester (villous, and non villous-trophoblast), term placenta and pregnant myometrium. Trophoblast tissue was obtained from psychosocial termination of pregnancy (9-12 weeks' gestation) wher...