Butyl paraben (BP) has antimicrobial effects and is widely used as a preservative in cosmetics, foods, and pharmaceuticals. It is also absorbed into various tissues of the human body. It is known that BP is measurable in maternal and fetal tissues during pregnancy, but the effects of BP on placental development, essential for maintaining normal pregnancy, are unclear. Therefore, we investigated the effect of BP on the proliferation, apoptosis, and invasiveness of human trophoblast cells, using an HTR8/SVneo cell line. BP inhibited cell proliferation and induced both apoptosis and endoplasmic reticulum stress. In addition, BP promoted the production of intracellular reactive oxygen species, increased Ca 2+ concentration in HTR8/SVneo cells, and induced mitochondrial membrane depolarization. BP also inhibited the activation of PI3K/AKT pathways including AKT, ribosomal protein S6, P70 S6 kinase, and glycogen synthase kinase 3β. Furthermore, pretreatment of cells with LY294002 (an AKT inhibitor) and U0126 (ERK1/2 inhibitor) revealed that ERK1/2 activity is also involved in BP‐mediated signal transduction in HTR8/SVneo cells. We therefore suggest that exposing human trophoblast cells to BP diminishes normal physiological activity, leading to apoptosis and problems with early placental development.
Numerous recent studies have shown that endocrine disrupting chemicals (EDCs) in the body of pregnant women can pass through the placenta and be exposed to the fetus, leading to fetal development and cognitive impairment. Placentation through invasion of trophoblast cells and vascular remodeling is essential to maintaining maternal and fetal health throughout the pregnancy. Abnormal placentation can lead to pregnancy disorders such as preeclampsia (PE) and intrauterine growth retardation (IUGR). However, many studies have not been conducted on whether EDCs can inhibit the development and function of the placenta. Isolating placental tissues to analyze the effect of EDCs on placentation has several limitations. In this review, we discussed the types of EDCs that can pass through the placental barrier and accumulate in the placenta with relative outcome. EDCs can be released from a variety of products including plasticizers, pesticides, and retardant. We also discussed the development and dysfunction of the placenta when EDCs were treated on trophoblast cells or pregnant rodent models. The effects of EDCs on the placenta of livestock are also discussed, together with the molecular mechanism of EDCs acting in trophoblast cells. We describe how EDCs cross the membrane of trophoblasts to regulate signaling pathways, causing genetic and epigenetic changes that lead to changes in cell viability and invasiveness. Further studies on the effects of EDCs on placenta may draw attention to the correct use of products containing EDCs during pregnancy.
This review summarizes the role of apoptosis in the trophoblast, one of the most important components of the placenta. The pathways of apoptosis induction, as well as receptors, ligands, and inhibitors involved in this process, are considered. The mechanisms of macrophage involvement in the regulation of trophoblast apoptosis are described, and the role of apoptosis in normal and pathological pregnancies is discussed.
Previous studies have linked prenatal polybrominated diphenyl ether (PBDE) exposure to adverse birth outcomes. Reductions in placental size might mediate those adverse effects. We examined whether umbilical cord blood PBDEs concentrations were associated with placental size at birth. A total of 121 mother-newborn pairs residing in Wenzhou were enrolled in this study. Concentrations of 19 PBDEs in umbilical cord blood were determined by gas chromatography tandem mass spectrometry (GC-MS). Placental length, breadth and surface area was measured by medical professionals after delivery. BDE-206, 207, 208, 209 and the total of 19 PBDE congeners concentrations were negatively associated with placental length, breadth and surface area. Our results suggest that prenatal PBDEs exposure may suppress placental growth, resulting in reduced placental size.
We propose and evaluate the hypothesis that parent‐offspring conflict over the degree of maternal investment has been one of the main selective factors in the evolution of vertebrate reproductive mode. This hypothesis is supported by data showing that the assumptions of parent‐offspring conflict theory are met for relevant taxa; the high number of independent origins of viviparity, matrotrophy (direct maternal‐fetal nutrient transfer), and hemochorial placentation (direct fetal access to the maternal bloodstream); the extreme diversity in physiological and morphological aspects of viviparity and placentation, which usually cannot be ascribed adaptive significance in terms of ecological factors; and divergent and convergent patterns in the diversification of placental structure, function, and developmental genetics. This hypothesis is also supported by data demonstrating that embryos and fetuses actively manipulate their interaction with the mother, thereby garnishing increased maternal resources. Our results indicate that selection may favor adaptations of the mother, the fetus, or both in traits related to reproductive mode and that integration of physiological and morphological data with evolutionary ecological data will be required to understand the adaptive significance of interspecific variation in viviparity, matrotrophy, and placentation.
Mothers can determine which genotypes of offspring they will produce through selective abortion or selective implantation. This process can, at some loci, favour matching between maternal and offspring genotype whereas at other loci mismatching may be favoured (e.g. MHC, HLA). Genomic imprinting generally renders gene expression monoallelic and could thus be adaptive at loci where matching or mismatching is beneficial. This hypothesis, however, remains unexplored despite evidence that loci known to play a role in genetic compatibility may be imprinted. We develop a simple model demonstrating that, when matching is beneficial, imprinting with maternal expression is adaptive because the incompatible paternal allele is not detected, protecting offspring from selective abortion. Conversely, when mismatching is beneficial, imprinting with paternal expression is adaptive because the maternal genotype is more able to identify the presence of a foreign allele in offspring. Thus, imprinting may act as a genomic 'cloaking device' during critical periods in development when selective abortion is possible.
Primates are quite unique among placental mammals in that the two extreme types of placentation are present within a single order. Strepsirrhines (lemurs and lorisiforms) have non-invasive epitheliochorial placentation, whereas haplorhines (tarsiers and higher primates) have highly invasive haemochorial placentation. Resemblance in placenta type in fact provided the first evidence that tarsiers are linked to higher primates and distinct from lemurs and lorisiforms. Tree-shrews differ from both primate subgroups in having moderately invasive endotheliochorial placentation, while colugos have invasive haemochorial placentation like haplorhines. All three kinds of placentation have been identified as primitive for placentals by different authors, but until recently the prevailing interpretation has been that non-invasive epitheliochorial placentation is primitive and “less efficient”. Opposing this interpretation, Martin (Primate origins and evolution: a phylogenetic reconstruction, 1990) proposed that moderately invasive endotheliochorial placentation is primitive. Epitheliochorial placentation is unlikely to be primitive because it is predominantly associated with large body size, relatively long gestation periods and precocial offspring. Furthermore, some strepsirrhines and other placental mammals with epitheliochorial placentation retain indications of former invasiveness of the placenta. The recent availability of comprehensive molecular phylogenies for placental mammals has provided an independent framework to determine the most parsimonious interpretation of the evolution of placenta types and other reproductive features. It has consistently emerged that epitheliochorial placentation is best explained as a derived condition, although opinions differ as to whether the ancestral condition for placental mammals (and hence for primates) was endotheliochorial or haemochorial. It is argued that on balance the most likely ancestral condition is endotheliochorial. Comparative evidence across placentals clearly indicates that epitheliochorial placentation is not less efficient than more invasive forms of placentation, at least with respect to growth in overall fetal body mass. The ratio of neonate mass to gestation period (a simple indicator of average daily maternal investment in fetal growth) shows no difference according to placenta type. Differential evolution of placentation is hence presumably linked to immunological factors, parent/offspring conflict and/or genomic imprinting.