Single-cell analysis reveals transcriptomic and epigenomic impacts on the maternal-fetal interface following SARS-CoV-2 infection

During pregnancy the maternal-fetal interface plays vital roles in fetal development. Its disruption is frequently found in pregnancy complications. Recent studies show increased incidences of adverse pregnancy outcomes in patients with COVID-19; however, the mechanism remains unclear. Here we analysed the molecular impacts of SARS-CoV-2 infection on the maternal-fetal interface. Generating bulk and single-nucleus transcriptomic and epigenomic profiles from patients with COVID-19 and control samples, we discovered aberrant immune activation and angiogenesis patterns in distinct cells from patients. Surprisingly, retrotransposons were also dysregulated in specific cell types. Notably, reduced enhancer activities of LTR8B elements were functionally linked to the downregulation of pregnancy-specific glycoprotein genes in syncytiotrophoblasts. Our findings revealed that SARS-CoV-2 infection induced substantial changes to the epigenome and transcriptome at the maternal-fetal interface, which may be associated with pregnancy complications.

Neonatal Antibiotic Treatment Can Affect Stool Pattern and Oral Tolerance in Preterm Infants

Preterm neonates are at high risk of infectious and inflammatory diseases which require antibiotic treatment. Antibiotics influence neonatal gut microbiome development, and intestinal dysbiosis has been associated with delayed gastrointestinal transit. Neonates who take less time to pass meconium have a better tolerance to enteral feeding. We analyzed the effect of neonatal antibiotic treatment on the stool pattern and oral tolerance in 106 preterm infants < 33 weeks gestational age. Neonates were classified in 3 groups according to neonatal antibiotic (ABT) treatment days: no antibiotics, 3−7 d ABT, and ≥8 d ABT. Preterm infants from the ≥8 d ABT group took longer to pass meconium and to start green and yellow stools, took longer to reach 100 and 150 mL/kg/day, and reached reduced volumes in enteral feeds at day of life 14 and 28 than infants from no ABT and 3−7 d ABT groups. Multiple linear regression models showed that neonatal antibiotic treatment, birth weight, invasive mechanical ventilation, surfactant, enteral feeding start day, neonatal parenteral nutrition, and neonatal fasting days are associated with the stool pattern and oral tolerance in preterm infants.

Intervention during the first 1000 days in Mexico

Health systems and society are facing the growing problem of obesity and its accompanying comorbidities. New approaches to reduce these problems must be oriented to population groups in which long-lasting effects of interventions may occur. Biological processes occurring during the first 1000 days of life, which may be modulated by environmental modifications and result in phenotypes with differential risk for noncommunicable chronic disease, constitute an opportunity for interventions. The nutritional and general health conditions of pregnant women and the fetus, as well as toddlers, can be improved with interventions during the first 1000 days, offering pregnancy care, promoting breastfeeding, instructing on the use of complementary foods, and educating on the adequacy of the family dietary patterns for children. Evidence that interventions during this period result in promotion of children's growth and development, influencing the risk for development of obesity in infancy, is available. In this article, an ongoing program in Mexico City directed to offer continuum of care during the first 1000 days is described.

Early-Life Dietary Cadmium Exposure and Kidney Function in 9-Year-Old Children from the PROGRESS Cohort

Cadmium (Cd) is a toxic metal associated with adverse health effects, including kidney injury or disease. The aims of this study were to estimate dietary Cd exposure during childhood, and to evaluate the association of early-life dietary Cd with biomarkers of glomerular kidney function in 9-year-old Mexican children. Our study included 601 children from the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) cohort with up to five follow-up food frequency questionnaires from 1 to 9 years of age; and 480 children with measures of serum creatinine, cystatin C, and blood nitrogen urea (BUN), as well as 9-year-old estimated glomerular filtration rate. Dietary Cd was estimated through food composition tables. Multiple linear regression models were used to analyze the association between 1 and 9 years, cumulative dietary Cd, and each kidney parameter. Dietary Cd exposure increased with age and exceeded the tolerable weekly intake (TWI = 2.5 µg/kg body weight) by 16-64% at all ages. Early-life dietary Cd exposure was above the TWI and we observed inverse associations between dietary Cd exposure and kidney function parameters. Additional studies are needed to assess kidney function trajectories through adolescence. Identifying preventable risk factors including environmental exposures in early life can contribute to decreasing the incidence of adult kidney disease.

The sFlt-1/PlGF ratio as a triage tool to identify superimposed preeclampsia in women with chronic hypertension in emergency rooms

OBJECTIVES

Assess the usefulness of the sFlt-1/PlGF ratio for the differential diagnosis of uncontrolled chronic hypertension vs. superimposed preeclampsia.

STUDY DESIGN

We performed a cross-sectional study from 2015 to 2017 and 42 women with initial diagnosis of superimposed preeclampsia were enrolled in the emergency room. After a 12 week follow up patients were grouped as superimposed preeclampsia (Group A) and uncontrolled chronic hypertension (Group B) according to the American College of Obstetricians and Gynecologist criteria. A group of 33 healthy women paired by gestational age were included as controls (Group C). Maternal serum levels of sFlt-1 and PlGF were measured at enrollment, and the ratios of the groups were compared.

MAIN OUTCOME MEASURES

Superimposed preeclampsia vs. uncontrolled chronic hypertension.

RESULTS

After follow-up, group distribution was 30 women in Group A, 12 women in Group B, and 25 women in Group C. The sFlt-1/PlGF ratio was higher in women with superimposed preeclampsia than in women with uncontrolled chronic hypertension (215.5 vs. 9.65, p < 0.001). The control group displayed lower ratio values (3.66, p < 0.001). The sFlt-1 concentration was higher in Group A than in Group B (7564 vs. 1281 pg/mL, p < 0.001) and the PlGF level was lower in Group A (34.39 vs. 169 pg/mL, p < 0.001).

CONCLUSIONS

The sFlt-1/PlGF ratio exhibits good performance for the differential diagnosis of superimposed preeclampsia vs. uncontrolled chronic hypertension.

Prenatal lead exposure and cord blood DNA methylation in PROGRESS: an epigenome-wide association study

The effects of prenatal lead exposure on child development include impaired growth and cognitive function. DNA methylation might be involved in the underlying mechanisms and previous epigenome-wide association studies reported associations between lead exposure during pregnancy and cord blood methylation levels. However, it is unclear during which developmental stage lead exposure is most harmful. Cord blood methylation levels were assayed in 420 children from a Mexican pre-birth cohort using the Illumina Infinium MethylationEPIC microarray. Lead concentrations were measured in umbilical cord blood as well as in blood samples from the mothers collected at 2nd and 3rd trimester and delivery using inductively coupled plasma-mass spectrometry. In addition, maternal bone lead levels were measured in tibia and patella using X-ray fluorescence. Comprehensive quality control and preprocessing of microarray data was followed by an unbiased restriction to methylation sites with substantial variance. Methylation levels at 202 111 cytosine-phosphate-guanine sites were regressed on each exposure adjusting for child sex, leukocyte composition, batch variables, gestational age, birthweight-for-gestational-age, maternal age, maternal education and mode of delivery. We find no association between prenatal lead exposure and cord blood methylation. This null result is strengthened by a sensitivity analysis showing that in the same dataset known biomarkers for birthweight-for-gestational-age can be recovered and the fact that phenotypic associations with lead exposure have been described in the same cohort.

Syncytiotrophoblast of Placentae from Women with Zika Virus Infection Has Altered Tight Junction Protein Expression and Increased Paracellular Permeability

The cytotrophoblast of human placenta transitions into an outer multinucleated syncytiotrophoblast (STB) layer that covers chorionic villi which are in contact with maternal blood in the intervillous space. During pregnancy, the Zika virus (ZIKV) poses a serious prenatal threat. STB cells are resistant to ZIKV infections, yet placental cells within the mesenchyme of chorionic villi are targets of ZIKV infection. We seek to determine whether ZIKV can open the paracellular pathway of STB cells. This route is regulated by tight junctions (TJs) which are present in the uppermost portion of the lateral membranes of STB cells. We analyzed the paracellular permeability and expression of E-cadherin, occludin, JAMs -B and -C, claudins -1, -3, -4, -5 and -7, and ZO-1, and ZO-2 in the STB of placentae from ZIKV-infected and non-infected women. In ZIKV-infected placentae, the pattern of expression of TJ proteins was preserved, but the amount of claudin-4 diminished. Placentae from ZIKV-infected women were permeable to ruthenium red, and had chorionic villi with a higher mean diameter and Hofbauer hyperplasia. Finally, ZIKV added to the basolateral surface of a trophoblast cell line reduced the transepithelial electrical resistance. These results suggest that ZIKV can open the paracellular pathway of STB cells.

Battle of epigenetic proportions: comparing Illumina's EPIC methylation microarrays and TruSeq targeted bisulfite sequencing

DNA methylation microarrays have been the platform of choice for epigenome-wide association studies in epidemiology, but declining costs have rendered targeted bisulphite sequencing a feasible alternative. Nonetheless, the literature for researchers seeking guidance on which platform to choose is sparse. To fill this gap, we conducted a comparison study in which we processed cord blood samples from four newborns in duplicates using both the Illumina HumanMethylationEPIC BeadChip and the Illumina TruSeq Methyl Capture EPIC Kit, and evaluated both platforms in regard to coverage, reproducibility, and identification of differential methylation. We conclude that with current analytic goals microarrays still outperform bisulphite sequencing for precise quantification of DNA methylation.

Prolactin selectively inhibits the LPS-induced chemokine secretion of human foetal membranes

Background: Inflammation is a condition that jeopardizes the continuity of pregnancy because it increases the secretion of chemokines that favor the migration of leukocytes from maternal and fetal circulations to the cervix, placenta, and the chorioamniotic membranes. During pregnancy, the level of prolactin (PRL) in the amniotic fluid is high; there is evidence to suggest that PRL contributes to maintain a privileged immune environment in the amniotic cavity. We test the effect of prolactin on the secretion profile of chemokines in human fetal membranes.Methods: Nine fetal membranes collected from healthy nonlabouring cesarean deliveries at term. We placed whole membrane explants in a two-chamber culture system. Choriodecidua and amniotic chambers were pretreated with 250, 500, 1000, or 4000 ng/ml of PRL for 24 h, then choriodecidua was cotreated with 500 ng/ml of lipopolysaccharide (LPS) and PRL for 24 h. We used ELISA to measure secreted levels of four chemokines (RANTES, monocyte chemoattractant protein 1 (MCP-1), MIP-1α, and IL-8) in both amnion and choriodecidua regions.Results: In comparison with basal conditions, LPS treatment induced significantly higher secretion of RANTES, MCP-1, and MIP-1α, but not of IL-8. RANTES was mainly produced by choriodecidua and cotreatment with PRL significantly decreased its LPS-induced secretion. MCP-1 was primarily produced by the amnion and its secretion was only inhibited by 4000 ng/ml of PRL. Both membrane regions produced MIP-1α, which was significantly inhibited at 1000 and 4000 ng/ml PRL concentrations. IL-8 showed no significant changes regardless of PRL concentration.Conclusion: PRL inhibits the differential secretion of proinflammatory chemokines by human fetal membranes.

Sensitivity of fasting glucose for gestational diabetes mellitus screening in Mexican adolescents based on International Association of Diabetes and Pregnancy Study Groups criteria: a diagnostic accuracy study based on retrospective data analysis

OBJECTIVE

To evaluate fasting plasma glucose (FPG) as a screening test for gestational diabetes mellitus (GDM) among Mexican adolescents using International Association of Diabetes and Pregnancy Study Groups criteria.

DESIGN

Retrospective cohort study.

SETTING

Level-three medical institution in Mexico City.

PARTICIPANTS

The study population comprised 1061 adolescent women aged 12-19 years with singleton pregnancies, who underwent a 75 g oral glucose tolerance test (OGTT) between 11 and 35 weeks of gestation.

PRIMARY AND SECONDARY OUTCOME MEASURES

The sensitivity (Sn), specificity (Sp), positive and negative predictive values (PPV and NPV, respectively), and positive and negative likelihood ratios LR (+) and LR (-), respectively) with 95% CIs for selected FPG cut-off values were compared. Secondary measures were perinatal outcomes in women with and without GDM.

RESULTS

GDM was present in 71 women (6.7%, 95% CI 5.3% to 8.4%). The performances of FPG at thresholds of ≥80 (4.5 mmol/L), 85 (4.7 mmol/L) and 90 mg/dL (5.0 mmol/L) were as follow (95% CI): Sn: 97% (89% to 99%), 94% (86% to 97%) and 91% (82% to 95%); Sp: 50% (47% to 53%), 79% (76% to 81%) and 97% (95% to 97%); PPV: 12% (9% to 15%), 23% (18% to 28%) and 64% (54% to 73%); NPV: 99% (98.5% to 99.9%) for all three cut-offs; LR (+): 1.9 (1.8 to 2.1), 4.3 (3.8 to 5.0) and 26.7 (18.8 to 37.1) and LR (-): 0.06 (0.02 to 0.23), 0.07 (0.03 to 0.19) and 0.09 (0.04 to 0.19), respectively. No significant differences in perinatal outcomes were found between adolescents with and without GDM.

CONCLUSIONS

An FPG cut-off of ≥90 mg/dL (5.0 mmol/L) is ideal for GDM screening in Mexican adolescent women. An FPG threshold of 90 mg/dL would miss 6 (8.5%) women with GDM, pick up 34 (3.4%) women without GDM and avoid 962 (90.7%) OGTTs.

Progesterone suppresses the lipopolysaccharide-induced pro-inflammatory response in primary mononuclear cells isolated from human placental blood

Progesterone is an essential hormone that induces deep immune adaptations favoring pregnancy maintenance. We aimed at evaluating the effects of progesterone on the synthesis of pro- and anti-inflammatory cytokines by mononuclear cells isolated from human placental blood stimulated with lipopolysaccharide, emulating an infection-inflammation environment. Mononuclear cells isolated form human placental blood were obtained from nine women undergoing elective cesarean delivery at term (not in labor), isolated by density gradient sedimentation, cultured and co-stimulated with lipopolysaccharide (500 ng/ml) from Escherichia coli in the presence or not of progesterone (0.01, 0.1, or 1.0 µM) for 24 h. Culture supernatants were assayed for pro-inflammatory (IL-1β, TNFα, IL-6), anti-inflammatory (IL-10) cytokines, chemokines (IL-8, MIP-1α) and total MMP-9 by ELISA. In comparison with basal conditions, lipopolysaccharide treatment induced IL-1β, TNFα, IL-6, IL-8, MIP-1α, and MMP-9 synthesis. lipopolysaccharide co-treatment with progesterone significantly decreased the bacterial endotoxin-induced IL-1β, TNF-α, IL-6, IL-8, and MIP-1α secretion. In contrast, co-treatment with progesterone increased the level of IL-10 secreted to the culture medium. The present results support the concept that progesterone can modulate--partially--the inflammatory response of professional immune cells isolated from placental blood. Therefore, progesterone might be part of the natural compensatory mechanism that limits the cytotoxic effects associated with an intrauterine infection process during gestation.

[The effect of corifollitropin alfa on in vitro fertilization-ICSI patients with previous failure with an FSH/HMG protocol: Preliminary report in Mexico]

BACKGROUND

The daily application of drugs, often in high doses, is a factor of stress for the infertile couple. During the last decade corifollitropin alpha has allowed a friendlier scheme comparable to traditional protocols (rFSH-HMG) results.

OBJECTIVE

To compare the results of corifollitropin alpha in patients with a previous cycle of IVF-ICSI with traditional scheme ovarian stimulation.

MATERIALS AND METHODS

Observational, retrospective cohort study type that infertile couples were included.

RESULTS

No significant differences in the dose used HFRS (2023U/ total ± 712 vs 636 U/total ± 307) and serum estradiol day shooting HGCr (1972 pg/dL vs 1107 ± 1152 pg/dL ± 775). A higher pregnancy rate was found corifollitropin alpha perhaps because it was a second attempt at in vitro fertilization.

CONCLUSIONS

Reproductive outcomes in a cycle of ovarian stimulation with corifollitropin are comparable with the results of a traditional ovarian stimulation cycle. It is important to broaden the experience of the drug indication in Mexican patients.

Progesterone elicits an inhibitory effect upon LPS-induced innate immune response in pre-labor human amniotic epithelium

PROBLEM

Infection of human fetal membranes elicits secretion of pro-inflammatory modulators through its innate immune capacities. We investigated the effect of lipopolysacharide (LPS) and progesterone (P4) upon expression of TLR-4/MyD88, TNFα, IL-6, IL-8, IL-10, and HBD2 on the human amniotic epithelium.

METHOD OF STUDY

Explants of the human amniotic epithelium were pre-treated with 0.01, 0.1, and 1.0 μM of P4; then cotreated with 1000 ng/mL LPS. TLR-4 was immuno-detected, and concentrations of MyD88, TNFα, IL-6, IL-8, IL-10, and HBD2 were quantified by ELISA.

RESULTS

P4 significantly reduced the expression of LPS-induced TLR-4/MyD88. LPS increased the concentrations of TNFα, IL-6, IL-8, IL-10, and HBD2 by factors of 30-, eight, three, three, and fivefold, respectively. P4 at 1.0 μM was the most effective dose to blunt the secretion of TNFα, IL-6, and HBD-2. RU-486 blocks the effect of P4.

CONCLUSION

P4 inhibited LPS-induced TLR-4/MyD88 and pro-inflammatory factors in the human amniotic epithelium. These results could explain partially how P4 can protect the amniotic region of fetal membranes and generate a compensatory mechanism that limits the secretion of pro-inflammatory modulators, which could jeopardize the immune privilege during pregnancy.

[Expression of cell adhesion molecules in the maternal fetal period of human gestation]

BACKGROUND

The human labor is an inflammatory process invading leukocytes modulated by gestational tissues. The local increase of cell adhesion molecules (CAMs) promotes the permanence of these leukocytes in the coriodecidua. Gestational tissues express ICAM-1, while circulating leukocytes expressing its ligand Mac-1.

OBJECTIVE

To analyze, first, if the expression of CAMs in the fetal membranes is associated with progress of gestational age, and second, the expression of CAMs on circulating leukocytes in the uterus (placenta).

MATERIAL AND METHOD

original and closed study conducted at the Instituto Nacional de Perinatologia Isidro Espinosa de los Reyes (Mexico City). We included samples from healthy women between 15 and 44 years of age with term pregnancies (> or =37 weeks gestation).

RESULTS

Real time PCR analysis showed that the expression of CAMs in the fetal membranes remained constant before labor. ICAM3 and ICAM1 tended to increase during labor, while ICAM2, VCAM1, SELE and SELP decrease with advancing gestational age. Placental leukocytes showed a clear increase in the expression of ITGAM (Mac-1) during labor.

CONCLUSIONS

These results show that the maternal-fetal interface expresses a specific combination of CAMs during labor, including ICAM1, ICAM-3 and Mac-1. The expression of these molecules could promote the retention of leukocytes in the local tissues to modulate the local inflammatory microenvironment during human labor.

Role of matrix metalloproteinases in preterm labour

Extracellular matrix homeostasis is a key process in the maintenance of the tensile strength of the amniochorion. This tensile strength guarantees the role of the membranes as a physical and functional boundary for the fetus during human pregnancy. Pathological rupture of these structures before 37 completed weeks of gestation is known as preterm prelabour rupture of the membranes (PPROM) and it is a major cause of spontaneous preterm labour and preterm birth. A mechanism involving the activation of matrix metalloproteinases (MMP)-9, a 92-kDa type IV collagenase, as an essential mediator of tissue damage is under investigation. The proposed mechanism involves the abnormal expression and activity of MMP-9 with subsequent connective tissue degradation taking place at a time that does not synchronise with other events of labour. The local physiological signal by amniochorion cells to induce MMP-9 expression is not known, but bacterial products and/or the proinflammatory cytokines, IL-1beta and TNF-alpha, as paracrine or autocrine signals may trigger these processes in pregnancies complicated with intra-amniotic infection. These signalling pathways indicate complex cooperative and bidirectional communications between amnion and choriodecidua in response to bacterial products, which include intermembranous cytokine traffic and signalling between tissues. Products secreted in culture by amniochorion and choriodecidual leucocytes, obtained from women who delivered following normal labour in the absence of infection, condition a specific microenvironment that induces collagen degradation in fetal membranes. Further characterisation of the role of choriodecidual leucocytes in the control of extracellular matrix degradation in amniochorion is currently under way.