Mechanisms of calcium transport across the placenta: Review

Studies of calcium transfer across the placenta have been reviewed because of the physiological and nutritional importance of this mineral during pregnancy, especially in order to better understand its contribution to development of the fetal skeleton. The placental transfer of maternal calcium to the fetus represents a vital mechanism for fetal development and breast-milk production, yet little meaningful information is currently available regarding the biochemical mechanisms involved in this process. Once again, the use of different animal models as rodents, rabbit, sheep and bovine have demonstrate different mechanisms of calcium transport across the placenta and contribute to better understand its effects in both fetus and mother during the gestation. In relation to the transfer of calcium from the mother to fetus data suggest it occur via an active mechanism;thus calcium concentration is higher in fetus than in maternal blood. Despite conflicting reports, several investigators agreed that calcium concentration in the fetal blood is mainly regulated by fetal parathyroid hormone and plasma concentration of vitamin D3, a metabolite that plays a key role in calcium transport through the syncytial cells.

Folic Acid Reverses the Effects of Cannabis on the Brain of New Born Wistar Rats

There are conflicting reports on the effect of Cannabis on brain cells, some reports support damage to brain cells while others do not. This work was carried out at the neuroscience unit of the Department of Veterinary Anatomy, University of Ibadan Oyo State, Nigeria. It investigated the neurodegenerative effect of extract of Cannabis sativa plant on brain regions in newborn Wistar rats exposed to Cannabis in utero and also combining the antioxidant and cell proliferative properties of folic acid to reverse these changes particularly in the Purkinje layer of the cerebellum in the group that received folic acid and cannabis. Four groups of pregnant Wistar rats were treated from Day 5 to 20 of pregnancy as follows: group A received 2ml of normal saline solution per os, group B received 2.0 mg /kg body weight of ethanolic extract of Cannabis sativa plant dissolved in normal saline per os, group C received 2.0 mg /kg body weight of Cannabis sativa extract and 40 mg/kg body weight of folic acid tablets (Emzor®) and group D received 2 mg/kg body weight of folic acid per os. The rat pups from group B showed deficit in locomotor function with spongiosis and astrogliosis in the corpus callosum, cerebellum and hippocampal regions of the brain. While pups from group A showed normal locomotor activities with no visible lesions in regions of the brain such as the cerebrum, cerebellum and the hippocampus. Group C pups were presented with normal locomotor activities with congestion of vessels in cerebrum and meninges and scattered areas of cell loss in the cerebrum, cerebellum hippocampus and corpus callosum and group D pups showed normal locomotor function, with vascular congestion in the meninges and cerebrum. We, therefore, concluded that folic acid which is a crucial factor in cell division, neurotransmitter production and an antioxidant in the nervous system could have a reversal of behavioural and locomotor deficits on nervous tissues exposed to Cannabis sativa extract by reducing the rate of cell death and increasing cellular stability and integrity in brain.

Role of Placenta Parameters in Predicting Significant Feto-Maternal Haemorrhage

Purpose: Feto-maternal haemorrhage (FMH) is a complication of pregnancy and large FMH may lead to life-threatening anaemia in the fetus or newborn. In addition, exposure of Rhesus (Rh) D negative women to small amounts of fetal Rh D positive red cells during pregnancy or delivery may result in sensitization with its attendant problems of isoimmunisation. In most cases, the cause of FMH IS unknown. Through this study, we sought to determine if placental weight & diameter have any direct relationship with incidence and severity of FMH.Methods: This was a prospective study of parturients for presence of fetal red cells in the maternal blood circulation. The prepared slide was processed as in the acid elution test described by Kleihauer-Betke. The FMH was calculated using Mollison formula. Baseline data included maternal biodata, blood group, Rh D factor, placenta weight and diameter. Data generated were analysed with Frequency tables, cross-tabulations and Odd ratio and confidence intervals as appropriate.Results: Three hundred parturients were studied. However, only two hundred and ninety-five parturients were analysed, with five excluded due to lysed blood samples. A total of 52 parturients (17.63%) had demonstrable FMH, of which 8 (2.71%) were large FMH (>15 ml foetal cells). Both the placenta weight (P g, in contrast to 4.17% (4/96) in the group with weight of placenta below or equal to 500 g. All the 8 parturients with large FMH had placenta weights greater than 500 g. Placenta diameters were greater than 22 cm in 41/197 (20.81%) who had demonstrable FMH, compared with 11/98 (11.23%) whose diameter was less than 22 cm. Conclusion:Both the placenta weight and diameter are significant predictors of FMH in parturients. However, placenta diameter appears to be a minor predictor. These are factors that can be assessed antenatally by ultrasonography and in conjunction with other known obstetric factors, may possibly be considered in risk-based scoring system for predicting feto-maternal haemorrhage.

Evaluation of materno-fetal antibody transfer in patients with antiphospholipid syndrome

Introduction:Antiphospholipid syndrome(APS)is characterized by thrombotic events and recurrent pregnancy losses and is considered the most common acquired thrombophilia.Objective:To carry out a narrative review of the transplacental passage and antibodies in patients with APS.Methods:A narrative literature review Results:When it is not associated with any connective tissue disease,it is said to be primary,and when in association with systemic lupus erythematosus,it is said to be secondary.Gestational morbidity is frequent,and it is crucial to evaluate the passage of these antibodies transplacentally since there are animal models of the syndrome with passive transfer of these antibodies.The transplacental passage of specific antibodies has already been determined in studies,which demonstrated low levels of these antibodies in the maternal serum,but an efficient transplacental passage for the newborn.Conclusions:There are few studies on this maternal-infant passage in patients with APS reviewed here.

Cell Permeability of Placenta in Mammal and Its Genetic Effect

Placenta is the place of material exchange between mother and fetus in mammals.But the maternal-fetal barrier is so effective that each keeps its own independence. Overthe past few years, there have been several reports proving that human fetal lymphocytescan migrate transplacentally and enter maternal circulation, and similar

Placental transfer of bisphenol diglycidyl ethers (BDGEs) and its association with maternal health in a population in South of China

Despite high production and usage,little is known about exposure to bisphenol diglycidyl ethers(BDGEs)and their derivatives in pregnant women and fetuses.In this study,we determined nine BDGEs in 106 paired maternal and cord serum samples collected from e-waste dismantling sites in South of China.Bisphenol A bis(2,3-dihydroxypropyl)glycidyl ether(BADGE⋅2H_(2)O),bisphenol A(3-chloro-2-hydroxypropyl)(2,3-dihydroxypropyl)glycidyl ether(BADGE⋅HCl⋅H_(2)O),and bisphenol F diglycidyl ether(BFDGE)were the major BDGEs,with median concentrations of 0.57,4.07,and 1.60 ng/mL,respectively,in maternal serum,and of 3.58,5.61,and 0.61 ng/mL,respectively,in cord serum.The transplacental transfer efficiencies(TTEs)were estimated for BDGEs found in samples,and median values were in the range of 0.98(BFDGE)to 5.91(BADGE⋅2H_(2)O).Our results suggested that passive diffusion plays a role in the placental transfer of BADGE⋅HCl⋅H_(2)O and BFDGE,whereas several mechanisms contribute to the high accumulation of BADGE⋅2H_(2)O in cord serum.Multiple linear regression analysis indicated significant associations between maternal serum concentrations of BDGEs and blood clinical biomarkers,especially those related to liver injuries,such as alanine aminotransferase(ALT),aspartate aminotransferase(AST),alkaline phosphatase(ALP),and adenosine deaminase(ADA)(P<0.05).To our knowledge,this is the first study to report the occurrence of BDGEs in paired maternal–fetal serum samples and provide new insights into prenatal and fetal exposures.The newly discovered TTEs in maternal–fetal pairs contribute to a fuller inventory of the transmission activity of pollutants in the human body,ultimately adding to a more significant comprehensive risk evaluation.