Macrophage migration inhibitory factor is up-regulated in human first-trimester placenta stimulated by soluble antigen of Toxoplasma gondii, resulting in increased monocyte adhesion on villous explants

Considering the potential role of macrophage migration inhibitory factor (MIF) in the inflammation process in placenta when infected by pathogens, we investigated the production of this cytokine in chorionic villous explants obtained from human first-trimester placentas stimulated with soluble antigen from Toxoplasma gondii (STAg). Parallel cultures were performed with villous explants stimulated with STAg, interferon-gamma (IFN-gamma), or STAg plus IFN-gamma. To assess the role of placental MIF on monocyte adhesiveness to human trophoblast, explants were co-cultured with human myelomonocytic THP-1 cells in the presence or absence of supernatant from cultures treated with STAg (SPN), SPN plus anti-MIF antibodies, or recombinant MIF. A significantly higher concentration of MIF was produced and secreted by villous explants treated with STAg or STAg plus IFN-gamma after 24-hour culture. Addition of SPN or recombinant MIF was able to increase THP-1 adhesion, which was inhibited after treatment with anti-MIF antibodies. This phenomenon was associated with intercellular adhesion molecule expression by villous explants. Considering that the processes leading to vertical dissemination of T. gondii remain widely unknown, our results demonstrate that MIF production by human first-trimester placenta is up-regulated by parasite antigen and may play an essential role as an autocrine/paracrine mediator in placental infection by T. gondii.

Potential role of interleukin-1 at the peri-ovulation stage in a species of placental viviparous reptile, the three-toed skink, Chalcides chalcides (Squamata: Scincidae)

We recently showed that interleukin-1 (IL-1) is secreted by the placenta of a species of squamate reptile, the three-toed skink, Chalcides chalcides. In this study, we used immunohistochemical techniques to investigate the expression of IL-1 (in the two isoforms, IL-1alpha and IL-1beta) and its specific membrane receptor IL-1 RtI in uterine oviduct during the peri-implantation period. We found that both IL-1 and its receptor were expressed in uterine tissues before and after ovulation (in the pre-ovulatory stage, even before the yolk had formed in the ovary). However, while IL-1alpha was mostly localized in the uterine mesenchyme tissue, IL-1beta and IL-1RtI were present in the uterine epithelium. Our data provide a further comparison between the reproduction of mammals and squamate reptiles.

Glycosylation of the materno-foetal interface in the pregnant viviparous placentotrophic lizard Chalcides chalcides: a lectin histochemical study

Glycosylation of the foeto-maternal interface of the skink Chalcides chalcides has been examined at various stages of gestation using lectin histochemistry. Specimens of incubatory chamber or placenta from early, mid-, late- and near-term pregnancy were fixed and embedded in epoxy resin. Areas of foeto-maternal apposition were probed with a panel of biotinylated lectins followed by an avidin-peroxidase revealing system to identify various classes of glycan at the interface. Both the external epithelium of unspecialized bilaminar omphalopleure, which forms by early pregnancy, and chorioallantoic membrane which develops by mid-pregnancy, were composed of two phenotypes, one of which secreted a wide range of glycans including high mannose and complex N-glycan, N-acetyl glucosamine, lactosamine and galactosamine, which became less prominent from mid-pregnancy onwards. The uterine epithelium also contained a well-developed secretory apparatus producing a similar range of glycans and there were indications that glycosylated secretions were taken up by the overlying chorioallantois. Foetal vasculature was well developed while maternal vessels appeared more contracted, and both were richly sialylated like their therian equivalents. Our findings indicate that this reptile has evolved a true epitheliochorial placenta with many aspects in common with its therian counterparts but also with unique features of its own.