Composition of the human placenta

Pratt, Joseph A.; Kaucher, Mildred; Moyer, Elsie Z.; Richards, Allen J.; Williams, Harold H.

doi:10.1016/0002-9378(46)90135-4

Cited by 19 publications

(5 citation statements)

References 10 publications

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“…Retention and biotransformation of environmental chemicals may occur in the placenta and affect the maternofetal transfer processes. Although the placenta is not lipid-rich as other tissues, it does contain more than 10% of lipids, allowing the distribution of lipophilic chemicals in the placenta. The human placenta contains a wealthy enzymatic machinery that is able to carry out both phase I and phase II reactions. ,, Therefore, placental retention and metabolism should be considered when determining the factors influencing transplacental transfer of environmental chemicals.…”

Section: Resultsmentioning

confidence: 99%

Transplacental Transfer of Environmental Chemicals: Roles of Molecular Descriptors and Placental Transporters

Sun

et al. 2020

Environ. Sci. Technol.

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Transplacental transfer of environmental chemicals results in direct risks to fetal development. Although numerous studies have investigated transplacental transfer efficiencies (TTEs) of environmental chemicals, the underlying mechanisms and influencing factors remain poorly understood. The present study aims to synthesize a current state of knowledge on the TTEs of major environmental chemicals and explore the roles of chemicals' molecular descriptors and placental transporters in the transplacental transfer. The results indicate great variations in TTEs (median: 0.29−2.86) across 51 chemicals. Chemical-dependent TTEs may partially be attributed to the influences of chemicals' molecular descriptors. Predictive models based on experimental TTEs and 1790 computed molecular descriptors indicate that a very limited number of molecular descriptors, such as the topological polar surface area, may substantially influence and efficiently predict chemicals' TTEs. In addition, molecular docking analyses were conducted to determine the binding affinities between 51 chemicals and six selected transporters, including BCRP, MDR1, hENT1, FRα, SERT, and MRP1. The results reveal transporter-and chemical-dependent binding affinities. Therefore, our study demonstrates that molecular descriptors and placental transporters, among a variety of other factors, can play important roles in the transplacental transfer of environmental chemicals. However, the underlying mechanisms and several important knowledge gaps identified herein require further investigations.

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Section: Resultsmentioning

confidence: 99%

Transplacental Transfer of Environmental Chemicals: Roles of Molecular Descriptors and Placental Transporters

Sun

et al. 2020

Environ. Sci. Technol.

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“…Cholesterol ( Figure 2B ) is an essential component of cell membranes influencing their integrity, fluidity, and permeability, equally important for the growing placenta and fetus. The human placenta needs more than 1 g of cholesterol for tissue growth ( Pratt et al, 1946 ) and the term human placenta manufactures approximately 400 mg of sex steroids from the precursor cholesterol per day ( Knopp et al, 1981 ). Cholesterol is essential for myelination ( Snipes and Suter, 1997 ) and as an activator and propagator of the sonic hedgehog-signaling pathway ( Blassberg and Jacob, 2017 ).…”

Section: Cholesterolmentioning

confidence: 99%

Physiology and Pathophysiology of Steroid Biosynthesis, Transport and Metabolism in the Human Placenta

2018

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The steroid hormones progestagens, estrogens, androgens, and glucocorticoids as well as their precursor cholesterol are required for successful establishment and maintenance of pregnancy and proper development of the fetus. The human placenta forms at the interface of maternal and fetal circulation. It participates in biosynthesis and metabolism of steroids as well as their regulated exchange between maternal and fetal compartment. This review outlines the mechanisms of human placental handling of steroid compounds. Cholesterol is transported from mother to offspring involving lipoprotein receptors such as low-density lipoprotein receptor (LDLR) and scavenger receptor class B type I (SRB1) as well as ATP-binding cassette (ABC)-transporters, ABCA1 and ABCG1. Additionally, cholesterol is also a precursor for placental progesterone and estrogen synthesis. Hormone synthesis is predominantly performed by members of the cytochrome P-450 (CYP) enzyme family including CYP11A1 or CYP19A1 and hydroxysteroid dehydrogenases (HSDs) such as 3β-HSD and 17β-HSD. Placental estrogen synthesis requires delivery of sulfate-conjugated precursor molecules from fetal and maternal serum. Placental uptake of these precursors is mediated by members of the solute carrier (SLC) family including sodium-dependent organic anion transporter (SOAT), organic anion transporter 4 (OAT4), and organic anion transporting polypeptide 2B1 (OATP2B1). Maternal–fetal glucocorticoid transport has to be tightly regulated in order to ensure healthy fetal growth and development. For that purpose, the placenta expresses the enzymes 11β-HSD 1 and 2 as well as the transporter ABCB1. This article also summarizes the impact of diverse compounds and diseases on the expression level and activity of the involved transporters, receptors, and metabolizing enzymes and concludes that the regulatory mechanisms changing the physiological to a pathophysiological state are barely explored. The structure and the cellular composition of the human placental barrier are introduced. While steroid production, metabolism and transport in the placental syncytiotrophoblast have been explored for decades, few information is available for the role of placental-fetal endothelial cells in these processes. With regard to placental structure and function, significant differences exist between species. To further decipher physiologic pathways and their pathologic alterations in placental steroid handling, proper model systems are mandatory.

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“…The amino-acids were studied by Koelker and Slemons (1911) and the different fatty constituents by Pratt, Kaucher, Moyer, Richards, and Williams (1946). Masters and Clayton (1940) were particularly interested in the amount of calcium in the placenta at different stages of maturity and Hilgenberg (1930) in the concentration of iron.…”

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confidence: 99%

Chemical Development in utero

Widdowson¹,

Spray²

1951

Archives of Disease in Childhood

549

178

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In spite of the spectacular advances in scientific medicine which we have witnessed in the last 20 years, there is still a need for information about a number of fundamental, if quite elementary, matters. One of these is the chemical composition of the human body. A knowledge of the quantitative make-up of the bodies of men, women, and children in both health and disease is of value for investigations of the most diverse types, but much of the information available is the result of guess work rather than chemistry. It is proposed to describe the results of an attempt to fill some of the gaps in our knowledge.Von Bezold (1857, 1858) was the first to make an analysis of a human foetus. It weighed 523 g., and he determined both organic and inorganic constituents. During the next 50 years a number of analyses were made, mostly in Germany and France, though one paper from Italy and one from Holland were published. Fehling (1877) studied 21 foetuses varying in weight from 1 to 3,294 g. He was interested only in the amounts of water, nitrogen, and fat, but most workers included inorganic constituents in their analyses (

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Composition of the human placenta

Cited by 19 publications

References 10 publications

Transplacental Transfer of Environmental Chemicals: Roles of Molecular Descriptors and Placental Transporters

Transplacental Transfer of Environmental Chemicals: Roles of Molecular Descriptors and Placental Transporters

Physiology and Pathophysiology of Steroid Biosynthesis, Transport and Metabolism in the Human Placenta

Chemical Development in utero

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