Clinical and in Vitro Evidence against Placenta Infection at Term by Severe Acute Respiratory Syndrome Coronavirus 2.

Despite occasional reports of vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy, the question of placental infection and its consequences for the newborn remain unanswered. Herein, we analyzed the placentas of 31 coronavirus disease 2019-positive mothers by reverse transcriptase PCR, immunohistochemistry, and in situ hybridization. Only one case of placental infection was detected, which was associated with intrauterine demise of the fetus. Differentiated primary trophoblasts were then isolated from nonpathologic human placentas at term, differentiated, and exposed to SARS-CoV-2 virions. Unlike for positive control cells Vero E6, the virus inside cytotrophoblasts and syncytiotrophoblasts or in the supernatant 4 days after infection was undetectable. As a mechanism of defense, we hypothesized that trophoblasts at term do not express angiotensin-converting enzyme 2 and transmembrane protease serine 2 (TMPRSS2), the two main host membrane receptors for SARS-CoV-2 entry. The quantification of these proteins in the placenta during pregnancy confirmed the absence of TMPRSS2 at the surface of the syncytium. Surprisingly, a transiently induced experimental expression of TMPRSS2 did not allow the entry or replication of the virus in differentiated trophoblasts. Altogether, these results underline that trophoblasts are not likely to be infected by SARS-CoV-2 at term, but raise concern about preterm infection.

Does soluble fms-like tyrosine kinase-1 regulate placental invasion? Insight from the invasive placenta.

OBJECTIVE: Soluble fms-like tyrosine kinase (sFLT-1) is a potent antiangiogenic growth factor that has been found to be markedly elevated in preeclampsia. In healthy pregnancy, serum sFLT-1 concentrations are 50-fold higher than in the nonpregnant state. The functional significance of this physiologic elevation in serum sFLT-1 in normal pregnancy is unknown. We hypothesized that sFLT-1 regulates placental cytotrophoblast invasion and that lower levels of sFLT-1 would be observed locally in invasive placentas (accreta/increta/percreta). STUDY DESIGN: We performed a retrospective case-control study comparing placental sFLT-1 expression in hysterectomy specimens from 3 groups: group 1, focally invasive placenta; group 2, normal invasion from the same specimen; and group 3, normal invasion associated with placenta previa. Immunohistochemistry for sFLT-1 was performed, and staining intensity was graded on a scale from 1+ (weak) to 5+ (strong). RESULTS: We identified 10 hysterectomy specimens from women with invasive placentation and 3 with placenta previa. The median sFLT-1 staining score for group 1 was 1.75 compared to 4.0 for group 2 (P = .01). A significant difference was also found between group 1 and group 3 (P = .01). When comparing depth of invasion, there was a trend toward lower staining score as depth of invasion increased (P = .11). Interobserver agreement for immunohistochemistry scoring was 87%. CONCLUSION: Lower levels of sFLT-1 protein expression were associated with invasive placentation suggesting a critical functional role for sFLT-1 in regulation of placental invasion.

Haem oxygenases play a pivotal role in placental physiology and pathology.

BACKGROUND: Haem oxygenases (HO) catabolise haem, which is the prosthetic group of numerous haemoproteins. Thus, multiple primary cellular pathways and functions rely on haem availability. HO exists in two isoforms, both expressed in the placenta, namely HO-1 and HO-2, the first being inducible. Haem oxygenases, particularly HO-1, have garnered specific interest in the field of physiological and pathological placental function. These enzymes mediate haem degradation by cleaving the alpha methene bridge to produce biliverdin, which is subsequently converted to bilirubin, carbon monoxide and iron. HO-1 has anti-inflammatory and antioxidant activities. SEARCH METHODS: An initial literature analysis was performed using PubMed on 3 October 2018 using key terms such as 'haem oxygenase and pregnancy', 'haem oxygenase and placenta', 'HO-1 and pregnancy', 'HO-1 and placenta', 'HO and placenta', 'HO and pregnancy', 'genetic variant and HO', 'CO and pregnancy', 'CO and placenta', 'Bilirubin and pregnancy', 'Iron and pregnancy' and 'PPAR and Haem', selecting consensus conferences, recommendations, meta-analyses, practical recommendations and reviews. A second literature analysis was performed, including notable miscarriages, foetal loss and diabetes mellitus, on 20 December 2019. The three authors studied the publications independently to decipher whether they should be included in the manuscript. OBJECTIVE AND RATIONALE: This review aimed to summarise current pieces of knowledge of haem oxygenase location, function and regulation in the placenta, either in healthy pregnancies or those associated with miscarriages and foetal loss, pre-eclampsia, foetal growth restriction and diabetes mellitus. OUTCOMES: HO-1 exerts some protective effects on the placentation, probably by a combination of factors, including its interrelation with the PGC-1α/PPAR pathway and the sFlt1/PlGF balance, and through its primary metabolites, notably carbon monoxide and bilirubin. Its protective role has been highlighted in numerous pregnancy conditions, including pre-eclampsia, foetal growth restriction, gestational diabetes mellitus and miscarriages. WIDER IMPLICATIONS: HO-1 is a crucial enzyme in physiological and pathological placentation. This protective enzyme is currently considered a potential therapeutic target in various pregnancy diseases.

Phosphorylation and carbonylation of placental proteins in normal pregnancy and gestosis.

Study of posttranslational changes in placental proteins revealed disorders in the intensity of their phosphorylation and carbonylation in patients with placental failure. Phosphorylation was reduced for the majority of endogenous placental proteins, substrates for cAMP- and cGMP-dependent protein kinases. An opposite dynamics was noted for oxidative modification of proteins. The content of carbonyl derivatives evaluated in spontaneous and metal-catalyzed oxidation of placental proteins was elevated in gestosis in comparison with the normal level.

Alkaline phosphatase histochemistry in human germ cell neoplasms.

Alkaline phosphatase is a useful and reliable marker of germ cell neoplasia that has been almost completely overlooked in the recent medical literature and in the practice of surgical pathology. Its presence in immature germ cells and in germ cell cancers was noted as early as 1953, but a systematic study of its use in the diagnosis and classification of germ cell tumors has not appeared in the literature. Using a recently developed plastic embedding technique combined with enzyme histochemistry, a large series of germ cell tumors and gonadal specimens were examined for the presence of alkaline phosphatase. The neoplastic germ cells in all cases of seminoma and embryonal carcinoma showed strong plasma membrane positivity for alkaline phosphatase. Choriocarcinomas (gestational and nongestational) and mature teratomas were negative. These findings suggest that the alkaline phosphatase reaction is a useful adjunct in the diagnosis of germ cell cancers.

Possible involvement of PKC isoforms in signalling placental apoptosis in intrauterine growth retardation.

Apoptosis contributes to uteroplacental dsyfunction in intrauterine growth retardation (IUGR). Specific protein kinase C (PKC) isoforms regulate apoptosis in other cell types. PKC isoforms thought to be anti-apoptotic include the conventional PKC isoforms (cPKC-alpha, -beta I and -beta II), whereas the novel PKC isoforms nPKC-delta and nPKC-epsilon may be apoptotic. Dexamethasone administration during the last third of pregnancy in the rat leads to IUGR. We used the dexamethasone model to test the hypothesis that adverse changes in fetal growth might be associated with a modified placental PKC isoform profile. Dexamethasone administered from day 15 of gestation via subcutaneous infusion (osmotic minipump; 100 or 200 microg dexamethasone/kg maternal body wt. per day) induced a dose-dependent decline in placental and fetal body weights at day 21 of gestation. Placental protein expression of all three cPKC isoforms was downregulated by maternal dexamethasone exposure, whereas placental nPKC-epsilon protein expression and activity was significantly upregulated in a dose-dependent manner. These data indicate that IUGR induced by excessive glucocorticoid exposure late in pregnancy leads to changes in the placental PKC isoform profile consistent with the concept that members of the PKC family participate in apoptosis signalling in the placenta.

A comparative study of five laboratory tests for foeto-placental dysfunction in late pregnancy.

Five foeto-placental function tests were studied in parallel in normal and abnormal late pregnancies with a view to establishing which test or tests is most satisfactorily able to identify the mother whose foetus is in danger.A critical examination of the levels in blood serum of two enzymes, placental phosphatase isoenzyme and cystine aminopeptidase, the polypeptide hormone placental lactogen (chorionic somatomammotrophin), and the oestrogen oestriol-17beta is described.A correlation was attempted beween clinical data and the results of the above laboratory analyses and also with the daily urine oestrogen output. The plasma and urine oestriol levels proved generally to be the more useful warning tests in late pregnancy, whilst the plasma cystine aminopeptidase was the least sensitive indicator of foeto-placental dysfunction.

Placental sulfatase deficiency: maternal and fetal expression of steroid sulfatase deficiency and X-linked ichthyosis.

PSD-X-linked ichthyosis are manifestations of a similar disorder of an inborn error of metabolism characterized by a deficiency of steroid sulfatase. The decreased enzyme activity is due to the absence of the expression of enzyme (steroid sulfatase) protein. Affected individuals with this disorder are males (X-linked inheritance) with a frequency of 1/2000 to 1/6000 births. Homozygous females from cosanguineous marriages have been reported with this disorder. The diagnosis is suspected and confirmed by: Low estriol excretion; Negative DHEAS loading test Increased DHEAS in amnionic fluid; Normal DHEAS in cord plasma; Possible delayed or abnormal labor patterns; Decreased sulfatase activity in the placenta, fibroblast, erythrocytes, lymphocytes or leukocytes of affected individuals; Development of ichthyosis in male infants at 2 to 3 months of age.

Aryl hydrocarbon hydroxylase activity in human placenta and threatened preterm delivery.

Induction of aryl hydrocarbon hydroxylase (AHH) activity in the placenta has been well documented. This enzyme may be induced by a variety of Polycyclic Aromatic Hydrocarbons (PAHs) and the AHH inducibility is associated with harmful effects of environmental chemicals. Toxic effects of PAHs in tissues such as placenta have been demonstrated to be due to their metabolites, epoxides, which interact with DNA. Thus, environmental PAHs may be related to its alterations in fetal development. Founded on these findings the PAH metabolites could interfere with the normal course of the pregnancy and may be an aborticide, a teratogen or a carcinogen. We hypothesize that low increased activity of placental Aryl Hydrocarbon Hydroxylase (AHH) may be an important determinant of human fetotoxicity. The present investigation was designed to examine the possible implications of PAH exposure at environmental exposure levels on the normal course of the pregnancy using AHH induction as an indicator of PAH exposure. Threatened Preterm Delivery (TPD) was used as an index of problems in the normal course of pregnancy. A group of forty pregnancies at term with TPD was compared with eighty controls for placental AHH induction. Macroscopic placental examination was also performed. A significant increase in prevalence of placental AHH induction with TPD was shown (Odds-Ratio = 2.8; 95% confidence bounds [1.3-6.2]; chi 2 = 6.7 p < 0.01). No such increases were found associated with placental pathology. When taking into account the group of placenta without basal plate calcifications, the significant increase in prevalence of placental AHH induction with TPD above mentioned was greatly increased (Odds-Ratio = 8.9; 95% confidence bounds [2.4-32.9]; chi 2 = 11.1 p < 0.001) controlling for gestational age. The increase in prevalence of placental AHH induction with TPD disappeared when taking into account the subgroup with basal plate or parenchyma calcifications. It is hypothesized that the high estrogen and progesterone at term may explain these associations.

Peripartal changes in serum alkaline phosphatase activity and lactate dehydrogenase activity in dairy cows.

Peripartal serum alkaline phosphatase activity and lactate dehydrogenase activity were measured in 30 dairy cows in order to examine the association between retained fetal membranes and enzyme activity. Daily blood samples were obtained from pregnant cows, starting 15 days before the expected day of calving until eight days after parturition. Sera from 15 cows which retained fetal membranes longer than 24 hours and 15 cows which shed fetal membranes within six hours after parturition were analyzed for alkaline phosphatase and lactate dehydrogenase enzyme activities. Mean alkaline phosphatase enzyme activities ranged from 15.93 to 32.6 U/L in retained and nonretained placenta cows. There was a trend towards higher serum alkaline phosphatase activities in retained placenta cows but the differences were not significant among the groups (P greater than 0.05). Mean lactate dehydrogenase activities ranged from 307.2 to 438.86 U/L in nonretained and retained placenta cows. Lactate dehydrogenase enzyme activities in nonretained and retained placenta cows were similar (P greater than 0.05). The alkaline phosphatase and lactate dehydrogenase enzyme activities peaked at the time of parturition in both groups. However, the differences in alkaline phosphatase and lactate dehydrogenase activities on different days within non-retained and retained placenta cows were significant (P less than 0.05). Results indicate that prepartal changes in alkaline phosphatase and lactate dehydrogenase enzyme activities are not predictive of placental retention postpartum.

Urinary oestrogen and plasma human placental lactogen as initial screening tests for a placental sulphatase deficiency.

As a result of routine screening of ante-natal patients by urinary total oestrogens and plasma human placental lactogen (HPL) from 35 weeks, a rare placental sulphatase deficiency was indicated which was later confirmed by in vitro studies of placental enzyme activities.

[Deficiency in placental sulfatase. Description of a recent case]. / Déficit en sulfatase placentaire. Description d'un nouveau cas

Synthesis of oestrogens occurs, during the greater part of pregnancy, in the placenta starting with two fetal precursors: DHA-S and 16 OH DHA-S. In the case of a deficit in sulphatase, an enzyme which is mainly localised in the placenta, these precursors cannot be transformed so that the level of oestrogens stays very low, without the level of secretion of progesterone being altered. Faced with such hormonal abnormalities it is worth while remembering the diagnosis of placental enzyme deficiency. In fact, this abnormality has no repercussions on the progress of the pregnancy and carries no danger for the fetus. It is therefore unnecessary to carry out untimely treatments thinking: fetal distress or adrenal agenesis be it primary or secondary (due to anencephaly) will occur. The diagnosis depends on simple dynamic tests: the mother receives an injection of free DHA and DHA-S, and enzyme study of the placenta can be confirmed in vitro. There seems to be a link between this abnormality and the sex of the fetus. All cases were followed by the birth of a normal boy. Finally, placental suphatase deficiency is rare, but it would appear that increased usage of hormone levels will reveal a rising number of such cases.

[Effect of protein-calorie restriction during pregnancy in rats, on the activity of glycolytic enzymes in the placenta]. / Efecto de la restricción calórico-proteínica durante el embarazo de la rata, en la actividad de algunas enzimas glicolíticas en la placenta.

The specific activities and changes of four placental enzymes: pyruvate kinase (PK), glucose-6-phosphate-dehydrogenase (G6PD), 6-phosphogluconic-dehydrogenase (6PGD), and NADP malate dehydrogenase (NADP-MD) occurring during the course of gestation and during maternal restricted food intake, were studied in rats. Enzymes activities are expressed in relation to DNA. With the progress of pregnancy, a significant increase in the activity of all enzymes, except NADP-MD, was observed in both groups. A 50% food restriction during pregnancy markedly decreased cell placental enzymes in different stages of development. PK was lower during early and late pregnancy, but NADP-MD was reduced only in the early developmental stage. The activities of G6PD and 6PGD were significantly lower only in the near-term stage in the malnourished group in comparison with the control group. Our findings suggest that this kind of nutritional insult markedly reduces glycolytic capacity and NADPH2 generation enzymes, a key factor in the placental steroids metabolism.

A fetal cyclooxygenase-2 gene polymorphism is associated with placental malperfusion.

Prostaglandin levels vary during pregnancy, mostly under the control of the inducible enzyme cyclooxygenase-2 (COX-2). The expression of COX-2 has been associated with ischemic events in the heart and brain, but its direct effect on human placental perfusion has not been previously examined. The purpose of this study was to investigate whether a functional polymorphism in the COX-2 gene that controls enzyme expression levels is associated with placental histopathologic lesions. Maternal and neonatal DNA from twin gestations were analyzed by a polymerase chain reaction-based assay for a single G to C nucleotide polymorphism at position -765 in the COX-2 gene promoter. Placental histopathology was evaluated in 6 major categories: meconium, malperfusion, inflammation, umbilical cord problems, villitis, and thrombosis. There was no significant association between placental histopathologic findings and polymorphisms of the COX-2 gene in the mother. In the fetus, carriage of the COX-2 C allele, which is correlated with decreased COX-2 gene expression, was negatively associated with lesions of placental ischemia/malperfusion (P = 0.02). Placental ischemic lesions were positively associated with intrauterine growth restriction (IUGR; P < 0.001). No other group of histopathologic lesions was associated with fetal polymorphisms in the COX-2 gene or with IUGR. Thus, a fetal polymorphism in the COX-2 gene influences the occurrence of placental malperfusion and ischemia, which may be of sufficient severity to promote or allow the development of IUGR.

Mice deficient in heparan sulfate 6-O-sulfotransferase-1 exhibit defective heparan sulfate biosynthesis, abnormal placentation, and late embryonic lethality.

Heparan sulfate (HS) plays critical roles in a variety of developmental, physiological, and pathogenic processes due to its ability to interact in a structure-dependent manner with numerous growth factors that participate in cellular signaling. The divergent structures of HS glycosaminoglycans are the result of the coordinate actions of several N- and O-sulfotransferases, C5-epimerase, and 6-O-endosulfatases. We have shown that 6-O-sulfation of the glucosamine residues in HS are catalyzed by the sulfotransferases HS6ST-1, -2, and -3. To determine the biological and physiological importance of HS6ST-1, we now describe the creation of transgenic mice that lack this sulfotransferase. Most of our HS6ST-1-null mice died between embryonic day 15.5 and the perinatal stage, and those mice that survived were considerably smaller than their wild-type littermates. Some of these HS6ST-1-null mice exhibited development abnormalities, and histochemical and molecular analyses of these mice revealed an approximately 50% reduction in the number of fetal microvessels in the labyrinthine zone of the placenta relative to that in the wild-type mice. Because we observed a modest reduction in VEGF-A mRNA and protein in the tissues of HS6ST-1-null mice, an HS-dependent defect in cytokine signaling probably contributes to increased embryonic lethality and decreased growth. Biochemical studies of the HS chains isolated from various organs of our HS6ST-1-null mice revealed a marked reduction of GlcNAc(6SO(4)) and HexA-GlcNSO(3)(6SO(4)) levels and a reduced ability to bind Wnt2. Thus, despite the presence of three closely related 6-O-sulfotransferase genes in the mouse genome, HS6ST-1 is the primary one used in HS biosynthesis in most tissues.

[Cystine aminopeptidase (CAP) and intrauterine death of the fetus]. / Cistina-amino-peptidasi (C.A.P.) e morte endouterina del feto.

13 pathologic pregnancies with intrauterine fetal death, serially monitored by C.A.P. determination, were retrospectively examined. In 81,81% of the cases the last C.A.P. value determinated before fetal death is situated below the--1 of standard deviation. Furthermore 50 cases with the last C.A.P. value situated below the--1 of standard deviation were considered: in 26% of these cases subsequentely happened intrauterine fetal death.