Stellate transformation of invasive trophoblast: a distinct phenotype of trophoblast that is involved in decidual vascular remodelling and controlled invasion during pregnancy

Abstract

BACKGROUND: Successful implantation relies on the tightly regulated invasion of extravillous trophoblasts (EVTs). However, little is known about their phenotypic differentiation and relevant motile behaviour. Furthermore, the cell-cell interactions between EVTs and decidual arterioles during physiological transformation are also poorly understood. METHODS: A total of 128 decidual specimens from early and late gestations containing components of EVTs and spiral arterioles were investigated using immunohistochemistry and periodic acid-Schiff reaction. RESULTS: Unipolar, tadpole-like EVTs are observed throughout the interstitial area, with a tendency to decrease along the invasive pathway. The stellate differentiation of the EVTs is identified around and inside decidual arterioles or in the third-trimester myometrium. Furthermore, stellate transformation of EVTs precedes its interactions with the decidual arteriole. These specialized stellate trophoblasts invade and infiltrate the tunica media, accompanying lacuna formation inside the vessel wall and perturbation of actin fibre alignment of the tunica media. CONCLUSION: Stellate transformation of trophoblasts may explain controlled invasion of EVTs and probably plays a key role in initiating cell-cell interaction in decidual vascular remodelling.

Trophoblast-Derived Exosomes Mediate Monocyte Recruitment and Differentiation

“…Successful pregnancy requires implantation and invasion of the trophoblast 1,2 . For the initial phase of trophoblast growth, the trophoblast must adopt an invasive phenotype and induce the formation of the fetal‐maternal circulation via maternal vascular system remodeling 3 . Many similarities exist between fetal implantation and tumor invasion; 4 however, in contrast to tumor invasion, trophoblast invasion is limited both spatially and temporally 5 .…”

Extracellular vesicles in host-pathogen interactions and immune regulation — exosomes as emerging actors in the immunological theater of pregnancy

“…As previously described, blastocyst implantation requires an inflammatory environment (Fest et al., 2007). The implantation process is achieved via the proper interaction of the innate uterine immune cells with the invading trophoblast (Huppertz et al., 1998; von Rango et al., 2003; Shih et al., 2006). During implantation, the uNK cells are pivotal for trophoblast invasion, and their absence is a predictor of poor vascularization of the placenta and pregnancy interruption (Hanna et al., 2006).…”

Mechanism of maternal vascular remodeling during human pregnancy

“…(1) What directs interstitial trophoblast invasion preferentially towards maternal spiral artery (perivascular invasion)? (2) What regulates the retrograde invasion along arterial lumen and subsequent replacement of EC by endovascular trophoblast (endovascular invasion)? In this section, we discuss the potential mechanism for perivascular and endovascular trophoblast invasion based on the relevant literatures.…”

“…These perivascular interstitial trophoblast cells disrupt the vascular smooth muscle cell (VSMC) layers and replace them with fibrinoid material. After embedding in the fibrinoid material, some of the perivascular trophoblast cells withdraw their dominant pseudopod and transform into a stellate shape [2].…”

“…Perivascular interstitial trophoblast destroys the VSMC layer and secretes fibrinoid material that is composed of fibronectin, collagen type IV, and laminin. As a result, perivascular interstitial trophoblast cells become embedded within this fibrinoid material, where some of them transform into stellate-shaped trophoblast [2].…”