Extravillous trophoblast

Extravillous Trophoblast (EVT) is a specialized type of cell that plays a crucial role in the process of placentation, the formation and function of the placenta. These cells originate from the trophoblast, a layer of cells surrounding the early embryo that will eventually form the placenta, an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply.

Function

The primary function of the EVT is to invade the maternal endometrium (the inner lining of the uterus) and its blood vessels. This invasion is essential for the remodeling of maternal spiral arteries, transforming them into large conduits of blood that are necessary to supply the growing fetus with adequate nutrients and oxygen. EVTs migrate into the maternal myometrium (the muscular layer of the uterus) and contribute to the establishment of a successful pregnancy by facilitating the exchange of gases, nutrients, and waste products between the mother and the fetus.

Types of Extravillous Trophoblasts

There are two main types of EVTs: interstitial EVTs, which invade the uterine stroma, and endovascular EVTs, which invade the walls of maternal vessels. Both types play a critical role in the modification of maternal spiral arteries and the establishment of the uteroplacental circulation.

Pathology

Abnormal EVT function or inadequate invasion of the maternal endometrium can lead to pregnancy-related complications such as pre-eclampsia, fetal growth restriction, and placental abruption. These conditions can have significant impacts on both maternal and fetal health, highlighting the importance of EVT in pregnancy.

Research and Clinical Significance

Understanding the mechanisms controlling EVT invasion and function has been a significant focus of reproductive biology research. Insights into these processes are crucial for developing therapeutic strategies to manage pregnancy complications associated with abnormal placental development and function.

See Also

• Placenta
• Trophoblast
• Pre-eclampsia
• Fetal growth restriction
• Placental abruption