Placental nutrient supply and fetal growth

Abstract

This review considers mechanisms by which transfer across the placenta takes place and how the capacity of the placenta to supply nutrients relates to fetal growth and vice versa. Blood flow through both uterine and umbilical circulations of the placenta, the structural properties of the placental exchange barrier and its related diffusional permeability, and the expression and activity of a wide range of transporter proteins in the syncytiotrophoblast, the transporting epithelium of the placenta, all need to be taken into account in considering placental supply capacity. We discuss the evidence that each of these factors affects, and is affected by, fetal growth rate and consider the regulatory mechanisms involved, with a particular focus on data that has emerged from study of the system A amino acid transporter. We consider that future work will build on the considerable foundation of knowledge regarding placental transfer mechanisms, as well as the other aspects of placental structure and function, to develop new diagnostic and therapeutic strategies for pregnancy complications, such as fetal growth restriction or overgrowth.

Macrophage-Derived IL-33 Is a Critical Factor for Placental Growth

“…Cell suspensions were filtered through a 70-mm cell strainer (BD Biosciences, Franklin Lakes, NJ) and separated by Percoll density gradient centrifugation (Pharmacia, Uppsala, Sweden). Cells between 35 and 50% of the Percoll layer were collected and incubated in RBC lysis buffer (155 mM NH 4 Cl, 10 mM KHCO 3 , and 0.1 mM EDTA [pH 7.3]) for 5 min at room temperature. Cells were taken up in DMEM/Ham's F-12 medium (PAA Laboratories, Pasching, Austria), supplemented with 10% FCS (PAA Laboratories), 0.05 mg/ml gentamicin, and 0.5 mg/ml fungizone (both from Life Technologies), and plated on plastic dishes for 40 min to remove contaminating fibroblasts.…”

“…7A). STs cover placental villi and fulfill substantial functions during pregnancy, such as nutrient and metabolite transport or hormone production (3,4). Determination of the EVT lineage starts with the formation of proliferative cell column trophoblasts (CCTs), which upon growth arrest differentiate into highly invasive EVTs (also referred to as interstitial cytotrophoblasts).…”

Human endogenous retrovirus K (HERV-K) is expressed in villous and extravillous cytotrophoblast cells of the human placenta

“…These EVT cells are in close contact with different cell types in the maternal decidua, including CD16 − /CD56 ++ natural killer and other immune cells that are known to control trophoblast invasion (Bulla et al, 2004). The function of the syncytiotrophoblast on the other hand is to produce hormones and to supply the fetal cells with nutrients (Desforges and Sibley, 2010).…”

Defining umbilical cord blood stem cells

“…The placenta is the organ that connects the developing fetus via the umbilical cord to the maternal uterine wall carrying out nutritive, respiratory, and excretory functions [18]. Similar to the umbilical cord, the placenta originate from the same zygote as the fetus.…”

“…The maternal portion contains the intervillous space, which is the space between the fetal chorionic villi and maternal blood vessels. The delicate walls of the chorionic villi allow the fetal blood to absorb nutrients and oxygen from the maternal blood and discard waste products into it without intermigration of the two blood currents [18,19].…”