Human Fetal Blood Research Articles

Single-cell multi-omics map of human fetal blood in Down syndrome

Down syndrome predisposes individuals to haematological abnormalities, such as increased number of erythrocytes and leukaemia in a process that is initiated before birth and is not entirely understood1–3. Here, to understand dysregulated haematopoiesis in Down syndrome, we integrated single-cell transcriptomics of over 1.1 million cells with chromatin accessibility and spatial transcriptomics datasets using human fetal liver and bone marrow samples from 3 fetuses with disomy and 15 fetuses with trisomy. We found that differences in gene expression in Down syndrome were dependent on both cell type and environment. Furthermore, we found multiple lines of evidence that haematopoietic stem cells (HSCs) in Down syndrome are ‘primed’ to differentiate. We subsequently established a Down syndrome-specific map linking non-coding elements to genes in disomic and trisomic HSCs using 10X multiome data. By integrating this map with genetic variants associated with blood cell counts, we discovered that trisomy restructured regulatory interactions to dysregulate enhancer activity and gene expression critical to erythroid lineage differentiation. Furthermore, as mutations in Down syndrome display a signature of oxidative stress4,5, we validated both increased mitochondrial mass and oxidative stress in Down syndrome, and observed that these mutations preferentially fell into regulatory regions of expressed genes in HSCs. Together, our single-cell, multi-omic resource provides a high-resolution molecular map of fetal haematopoiesis in Down syndrome and indicates significant regulatory restructuring giving rise to co-occurring haematological conditions.

MYCT1 controls environmental sensing in human haematopoietic stem cells

The processes that govern human haematopoietic stem cell (HSC) self-renewal and engraftment are poorly understood and challenging to recapitulate in culture to reliably expand functional HSCs1–3. Here we identify MYC target 1 (MYCT1; also known as MTLC) as a crucial human HSC regulator that moderates endocytosis and environmental sensing in HSCs. MYCT1 is selectively expressed in undifferentiated human haematopoietic stem and progenitor cells (HSPCs) and endothelial cells but becomes markedly downregulated during HSC culture. Lentivirus-mediated knockdown of MYCT1 prevented human fetal liver and cord blood (CB) HSPC expansion and engraftment. By contrast, restoring MYCT1 expression improved the expansion and engraftment of cultured CB HSPCs. Single-cell RNA sequencing of human CB HSPCs in which MYCT1 was knocked down or overexpressed revealed that MYCT1 governs important regulatory programmes and cellular properties essential for HSC stemness, such as ETS factor expression and low mitochondrial activity. MYCT1 is localized in the endosomal membrane in HSPCs and interacts with vesicle trafficking regulators and signalling machinery. MYCT1 loss in HSPCs led to excessive endocytosis and hyperactive signalling responses, whereas restoring MYCT1 expression balanced culture-induced endocytosis and dysregulated signalling. Moreover, sorting cultured CB HSPCs on the basis of lowest endocytosis rate identified HSPCs with preserved MYCT1 expression and MYCT1-regulated HSC stemness programmes. Our work identifies MYCT1-moderated endocytosis and environmental sensing as essential regulatory mechanisms required to preserve human HSC stemness. Our data also pinpoint silencing of MYCT1 as a cell-culture-induced vulnerability that compromises human HSC expansion.

MYCT1 Controls Environmental Sensing to Maintain Self-Renewal in Human Hematopoietic Stem Cells

Hematopoietic stem cells (HSC) sustain life-long blood production and have the ability to recapitulate the hematopoietic system upon transplantation. This makes them therapeutically invaluable for the treatment of hematopoietic malignancies and genetic disorders. However, the regulatory processes governing HSC functional competence and engraftment ability are poorly understood and challenging to recapitulate ex vivo, making robust expansion of human HSCs difficult to achieve. We have identified a novel HSC regulatory protein, MYCT1 (MYC target 1), that is highly enriched in self-renewing human HSC but lost during differentiation and culture. Knockdown (KD) experiments in human fetal liver and cord blood revealed a critical requirement for MYCT1 in human HSPC ex vivo expansion and engraftment across HSC ontogeny. Single cell RNAseq of human HSPCs upon MYCT1 KD linked MYCT1 loss in HLF+ HSCs to a profound dysregulation of cellular programs essential for HSC stemness, including mitochondrial activity, proteostasis and splicing. Because MYCT1 becomes drastically downregulated during HSC ex vivo culture, we investigated if restoring MYCT1 expression in culture could improve HSC function. Indeed, maintaining MYCT1 levels during culture via lentiviral expression resulted in improved “stemness” transcriptional signatures, greater expansion of the most undifferentiated EPCR+ITGA3+ human HSPCs, and enhanced engraftment ability upon transplantation. Notably, we also uncovered that the novel albumin free culture conditions reported by Sakurai et al. 2023 to robustly expand human HSCs can also maintain higher levels of MYCT1 expression. This reinforces our findings that the loss of MYCT1 expression is a major contributor to the functional incompetence of human HSCs cultured ex vivo. Nonetheless, the MYCT1 regulated processes and why they are critical for HSC competence are not known. Immunofluorescence and IP-mass spectrometry revealed that MYCT1 localizes in the endosomal membrane and interacts with vesicle trafficking machinery and receptor signaling components essential for HSC function. MYCT1 KD in human HSCs and endothelial cells (EC) led to hyperactive endocytosis and caused exaggerated signaling responses to cytokines in the culture microenvironment. We found that ex vivo culture gradually increased endocytosis specifically in CD34+ EPCR+ HSPCs in parallel with the culture-induced downregulation of MYCT1 in these cells, but not in the more differentiated progeny. On the other hand, restoring MYCT1 expression during HSC culture dampened the excessive endocytosis. Furthermore, maintaining low endocytosis during culture, either by the endocytosis inhibitor chlorpromazine or by sorting HSPCs with lower endocytic internalization of fluorescent dextran, results in the enrichment of immunophenotypic LT-HSCs in culture. Our data show that the moderation of environmental sensing through MYCT1-controlled endocytosis is essential for preserving human HSC self-renewal and engraftment ability. As MYCT1 expression is downregulated in cultured human HSPC, our findings imply that loss of the molecular machinery required for proper sensing of microenvironment signals has far-reaching effects into essential cellular functions required for stemness, and is a key contributor to the functional incompetence of cultured human HSC.

Flickering of fetal erythrocytes membrane under gestational diabetes observed with dual time resolved membrane fluctuation spectroscopy

The membrane flickering of human fetal red blood cells (RBCs) affected by gestational diabetes mellitus (GDM) was studied with dual time resolved membrane fluctuation spectroscopy (D-TRMFS). This new technique is a modified version of the dual optical tweezers method that has been adapted to measure the mechanical properties of RBCs at two distant membrane points simultaneously. The micro-rheological parameters were obtained from direct membrane flickering measurements, followed by Fourier decomposition and cell membrane model adjustment. Our results show a significant decrease of 6.01 ± 1.19 nm in membrane fluctuations amplitude in healthy fetal, compared with healthy adult RBCs, meanwhile the amplitude in GDM cells increased 3.22 ± 1.10 nm compared with healthy fetal RBCs. Between GDM and healthy fetal RBCs, there are significant differences, especially in the bending modulus. Considering the mean of the two membrane points measured, the tension for GDM RBCs increased by 6.431 ± 3.57 (10−7 [N/m]) compared with healthy fetal RBCs, meanwhile, the bending was increased by 2.483 ± 0.58 (10−19 [J]) in GDM compared with healthy fetal RBCs. These results showed significant increment of 1.23 ± 0.07-fold and 3.29 ± 0.36-fold in tension and bending modulus in GDM, respectively. The strong impact of GDM on bending modulus could be associated with oxidative stress and lipid peroxidation, previously reported in fetal plasma of GDM cases.

Single-cell multiomics of human fetal hematopoiesis define a developmental-specific population and a fetal signature.

Knowledge of human fetal blood development and how it differs from adult blood is highly relevant to our understanding of congenital blood and immune disorders and childhood leukemia, of which the latter can originate in utero. Blood formation occurs in waves that overlap in time and space, adding to heterogeneity, which necessitates single-cell approaches. Here, a combined single-cell immunophenotypic and transcriptional map of first trimester primitive blood development is presented. Using CITE-seq (cellular indexing of transcriptomes and epitopes by sequencing), the molecular profile of established immunophenotype-gated progenitors was analyzed in the fetal liver (FL). Classical markers for hematopoietic stem cells (HSCs), such as CD90 and CD49F, were largely preserved, whereas CD135 (FLT3) and CD123 (IL3R) had a ubiquitous expression pattern capturing heterogenous populations. Direct molecular comparison with an adult bone marrow data set revealed that the HSC state was less frequent in FL, whereas cells with a lymphomyeloid signature were more abundant. An erythromyeloid-primed multipotent progenitor cluster was identified, potentially representing a transient, fetal-specific population. Furthermore, differentially expressed genes between fetal and adult counterparts were specifically analyzed, and a fetal core signature was identified. The core gene set could separate subgroups of acute lymphoblastic leukemia by age, suggesting that a fetal program may be partially retained in specific subgroups of pediatric leukemia. Our detailed single-cell map presented herein emphasizes molecular and immunophenotypic differences between fetal and adult blood cells, which are of significance for future studies of pediatric leukemia and blood development in general.

A Biodegradable Flexible Micro/Nano-Structured Porous Hemostatic Dental Sponge.

A biodegradable micro/nano-structured porous hemostatic gelatin-based sponge as a dentistry surgery foam was prepared using a freeze-drying method. In vitro function evaluation tests were performed to ensure its hemostatic effect. Biocompatibility tests were also performed to show the compatibility of the sponge on human fetal foreskin fibroblasts (HFFF2) cells and red blood cells (RBCs). Then, 10 patients who required the extraction of two teeth were selected, and after teeth extraction, for dressing, the produced sponge was placed in one of the extracavities while a commercial sponge was placed in the cavity in the other tooth as a control. The total weight of the absorbed blood in each group was compared. The results showed a porous structure with micrometric and nanometric pores, flexibility, a two-week range for degradation, and an ability to absorb blood 35 times its weight in vitro. The prepared sponge showed lower blood clotting times (BCTs) (243.33 ± 2.35 s) and a lower blood clotting index (BCI) (10.67 ± 0.004%) compared to two commercial sponges that displayed its ability for faster coagulation and good hemostatic function. It also had no toxic effects on the HFFF2 cells and RBCs. The clinical assessment showed a better ability of blood absorption for the produced sponge (p-value = 0.0015). The sponge is recommended for use in dental surgeries because of its outstanding abilities.

Effector Vγ9Vδ2 T cell response to congenital Toxoplasma gondii infection.

A major γδ T cell population in human adult blood are the Vγ9Vδ2 T cells that are activated and expanded in a TCR-dependent manner by microbe-derived and endogenously derived phosphorylated prenyl metabolites (phosphoantigens). Vγ9Vδ2 T cells are also abundant in human fetal peripheral blood, but compared with their adult counterparts they have a distinct developmental origin, are hyporesponsive toward in vitro phosphoantigen exposure, and do not possess a cytotoxic effector phenotype. In order to obtain insight into the role of Vγ9Vδ2 T cells in the human fetus, we investigated their response to in utero infection with the phosphoantigen-producing parasite Toxoplasma gondii (T. gondii). Vγ9Vδ2 T cells expanded strongly when faced with congenital T. gondii infection, which was associated with differentiation toward potent cytotoxic effector cells. The Vγ9Vδ2 T cell expansion in utero resulted in a fetal footprint with public germline-encoded clonotypes in the Vγ9Vδ2 TCR repertoire 2 months after birth. Overall, our data indicate that the human fetus, from early gestation onward, possesses public Vγ9Vδ2 T cells that acquire effector functions following parasite infections.

Human Fetal Blood Flow Quantification with Magnetic Resonance Imaging and Motion Compensation.

Magnetic resonance imaging (MRI) is an important tool for the clinical assessment of cardiovascular morphology and heart function. It is also the recognized standard-of-care for blood flow quantification based on phase contrast MRI. While such measurement of blood flow has been possible in adults for decades, methods to extend this capability to fetal blood flow have only recently been developed. Fetal blood flow quantification in major vessels is important for monitoring fetal pathologies such as congenital heart disease (CHD) and fetal growth restriction (FGR). CHD causes alterations in the cardiac structure and vasculature that change the course of blood in the fetus. In FGR, the path of blood flow is altered through the dilation of shunts such that the oxygenated blood supply to the brain is increased. Blood flow quantification enables assessment of the severity of the fetal pathology, which in turn allows for suitablein uteropatient management and planning for postnatal care. The primary challenges of applying phase contrast MRI to the human fetus include small blood vessel size, high fetal heart rate, potential MRI data corruption due to maternal respiration, unpredictable fetal movements, and lack of conventional cardiac gating methods to synchronize data acquisition. Here, we describe recent technical developments from our lab that have enabled the quantification of fetal blood flow using phase contrast MRI, including advances in accelerated imaging, motion compensation, and cardiac gating.

Human Fetal Blood Flow Quantification with Magnetic Resonance Imaging and Motion Compensation

Human Fetal Blood Flow Quantification with Magnetic Resonance Imaging and Motion Compensation

Normal human and sheep fetal vessel oxygen saturations by T2 magnetic resonance imaging.

Human fetal Doppler ultrasound and invasive blood gas measurements obtained by cordocentesis or at the time of delivery reveal similarities with sheep (an extensively used model for human fetal cardiovascular physiology). Oxygen saturation (SO2 ) measurements in human fetuses have been limited to the umbilical and scalp vessels, providing little information about normal regional SO2 differences in the fetus. Blood T2 MRI relaxometry presents a non-invasive measure of SO2 in the major fetal vessels. This study presents the first in vivo validation of fetal vessel T2 oximetry against the in vitro T2-SO2 relationship using catheterized sheep fetuses and compares the normal SO2 in the major vessels between the human and sheep fetal circulations. Human fetal vessel SO2 by T2 MRI confirms many similarities with the sheep fetal circulation and is able to demonstrate regional differences in SO2 ; in particular the significantly higher SO2 in the left versus right heart. Blood T2 magnetic resonance imaging (MRI) relaxometry non-invasively measures oxygen saturation (SO2 ) in major vessels but has not been validated in fetuses in vivo. We compared the blood T2-SO2 relationship in vitro (tubes) and in vivo (vessels) in sheep, and measured SO2 across the normal human and sheep fetal circulations by T2. Singleton pregnant ewes underwent surgery to implant vascular catheters. In vitro and in vivo sheep blood T2 measurements were related to corresponding SO2 measured using a blood gas analyser, as well as relating T2 and SO2 of human fetal blood in vitro. MRI oximetry was performed in the major vessels of 30 human fetuses at 36 weeks (term, 40 weeks) and 10 fetal sheep (125 days; term, 150 days). The fidelity of in vivo fetal T2 oximetry was confirmed through comparison of in vitro and in vivo sheep blood T2-SO2 relationships (P=0.1). SO2 was similar between human and sheep fetuses, as was the fetal oxygen extraction fraction (human, 33±11%; sheep, 34±7%; P=0.798). The presence of streaming in the human fetal circulation was demonstrated by the SO2 gradient between the ascending aorta (68±10%) and the main pulmonary artery (49±9%; P<0.001). Human and sheep fetal vessel MRI oximetry based on T2 is a validated approach that confirms the presence of streaming of umbilical venous blood towards the heart and brain. Streaming is important in ensuring oxygen delivery to these organs and its disruption may have important implications for organ development, especially in conditions such as congenital heart disease and fetal growth restriction.

Targeting ABL1 or ARG Tyrosine Kinases to Restrict HIV-1 Infection in Primary CD4+ T-Cells or in Humanized NSG Mice.

Previous studies support dasatinib as a potent inhibitor of HIV-1 replication. However, a functional distinction between 2 kinase targets of the drug, ABL1 and ARG, has not been assessed. We used primary CD4 T-cells, CD8-depleted peripheral blood mononuclear cells (PBMCs) from a treatment naïve HIV-1 patient, and a humanized mouse model of HIV-1 infection. We assessed the roles of ABL1 and ARG during HIV-1 infection and use of dasatinib as a potential antiviral against HIV-1 in humanized mice. Primary CD4 T-cells were administered siRNA targeting ABL1 or ARG, then infected with HIV-1 containing luciferase reporter viruses. Quantitative polymerase chain reaction of viral integration of 4 HIV-1 strains was also assessed. CD8-depleted PBMCs were treated for 3 weeks with dasatinib. NSG mice were engrafted with CD34 pluripotent stem cells from human fetal cord blood, and infected with Ba-L virus after 19 weeks. Mice were treated daily with dasatinib starting 5 weeks after infection. siRNA knockdown of ABL1 or ARG had no effect on viral reverse transcripts, but increased 2-LTR circles 2- to 4-fold and reduced viral integration 2- to 12-fold. siRNA knockdown of ARG increased SAMHD1 activation, whereas knockdown of either kinase reduced RNA polymerase II activation. Treating CD8-depleted PBMCs from a treatment-naïve patient with 50 nM of dasatinib for 3 weeks reduced p24 levels by 99.8%. Ba-L (R5)-infected mice injected daily with dasatinib showed a 95.1% reduction in plasma viral load after 2 weeks of treatment. We demonstrate a novel nuclear role for ABL1 and ARG in ex vivo infection experiments, and proof-of-principle use of dasatinib in a humanized mouse model of HIV-1 infection.

Insulin-Like Peptide 3 (INSL3) Serum Concentration During Human Male Fetal Life.

Context: Insulin-like peptide 3 (INSL3), a protein hormone produced by Leydig cells, may play a crucial role in testicular descent as male INSL3 knockout mice have bilateral cryptorchidism. Previous studies have measured human fetal INSL3 levels in amniotic fluid only.Objective: To measure INSL3 serum levels and mRNA in fetal umbilical cord blood and fetal testes, respectively.Design: INSL3 concentrations were assayed on 50 μl of serum from male human fetal umbilical cord blood by a non-commercial highly sensitive and specific radioimmunoassay. For secondary confirmation, quantitative real-time PCR was used to measure INSL3 relative mRNA expression in 7 age-matched human fetal testes.Setting: UT Southwestern Medical Center, Dallas, TX and Medical University of South Carolina, Charleston, SC.Patients or other Participants: Twelve human male umbilical cord blood samples and 7 human male testes were obtained from fetuses 14–21 weeks gestation. Male sex was verified by leukocyte genomic DNA SRY PCR.Interventions: None.Main Outcome Measures: Human male fetal INSL3 cord blood serum concentrations and testicular relative mRNA expression.Results: INSL3 serum concentrations during human male gestational weeks 15–20 were 2–4 times higher than published prepubertal male levels and were 5–100 times higher than previous reports of INSL3 concentrations obtained from amniotic fluid. Testicular fetal INSL3 mRNA relative expression was low from weeks 14–16, rose significantly weeks 17 and 18, and returned to low levels at week 21.Conclusions: These findings further support the role of INSL3 in human testicular descent and could prove relevant in uncovering the pathophysiology of cryptorchidism.

PLACENTAL CYTOPATHIC DAMAGE FACTOR DUE TO PARVOVIRUS B19 – AS A HALLMARK OF INTRAUTERINE SYMPTOMATHY OF INFECTED FETUS

Aim of the work. The focus of this study was to analyze the frequency of fetal intrauterine symptomatic realization as a result of B19 parvovirus infection of pregnant women during I and II gestation periods, with the combination of determination the levels of alpha-fetoprotein in maternal serum blood and histopathological investigation of placenta in cases of negative effects for infected fetuses. Materials and methods. A total of 478 pregnant women were at risk of infection and screened for parvovirus B19. The study was based on serological, morphological and virological testing of fetuses from mothers with confirmed parvovirus B19 infection. Infection of pregnant women was detected by serological diagnosis of specific antibodies IgM and IgG to parvovirus B19. Intrauterine fetal infection was confirmed by polymerase chain reaction method. Levels of alpha-fetoprotein in meternal venous blood were detected using an immunochemical test method. An antenatal diagnosis of hydrops fetalis was confirmed by ultrasound scanning. Placenta from the 8 infected fetuses was studied histologically with hematoxylin and eosin staining using electron microscope during gestational periods of 12-22 weeks. Statistical analysis of the obtained data was carried out using nonparametric statistics with the definition of Fisher's criterion. Results and discussion. The average gestational period of symptomatic manifestations of intrauterine fetal infection was 19.9±0.5 weeks of gestation. It was established that in 33 of cases were confirmed the intrauterine infection due to parvovirus B19 by using the morphological placenta tissue analysis. The research found that the levels of maternal serum alpha-fetoprotein was significantly higher (in 2.17 times) in group of fetuses who suffered from fetal hydrops and in cases of intrauterine fetal death before detecting the general echographic sings of fetal failure (p˂0.05). It will be very important to compare this indicator with the Doppler ultrasound measurements of the human fetal middle cerebral artery peak systolic velocity (MCA PSV) and blood flow parameters in the fetal ductus venosus and to predict the possibility of poor perinatal outcomes. It was identified a cytopathic effect in placental cells viral origin and detected in cells of the cytotrophoblast, syncytiotrophoblast, endothelial cells, and blood cells. Conclusions. Parvovirus B19 fractions were visualized in 100 % of cases of miscarriages with fetal hydrops and placental edema during 12-22 weeks of gestation, while acute maternal parvovirus infection (with the detection of IgM against to parvovirus B19) was diagnosed by immunoassay only in 62.5 % of cases. Detection of B19 particles in placental tissue from fetuses with non-immune origin hydrops is an auxiliary method in the diagnosis of vertical transmission of parvovirus during pregnancy. It is more preferable to estimate the levels of alpha-fetoprotein in maternal serum blood in case of parvovirus B19 affected pregnancies as raising rates of this marker may be an early prediction hallmark for adverse fetal outcome.

MSX2 Initiates and Accelerates Mesenchymal Stem/Stromal Cell Specification of hPSCs by Regulating TWIST1 and PRAME

SummaryThe gap in knowledge of the molecular mechanisms underlying differentiation of human pluripotent stem cells (hPSCs) into the mesenchymal cell lineages hinders the application of hPSCs for cell-based therapy. In this study, we identified a critical role of muscle segment homeobox 2 (MSX2) in initiating and accelerating the molecular program that leads to mesenchymal stem/stromal cell (MSC) differentiation from hPSCs. Genetic deletion of MSX2 impairs hPSC differentiation into MSCs. When aided with a cocktail of soluble molecules, MSX2 ectopic expression induces hPSCs to form nearly homogeneous and fully functional MSCs. Mechanistically, MSX2 induces hPSCs to form neural crest cells, an intermediate cell stage preceding MSCs, and further differentiation by regulating TWIST1 and PRAME. Furthermore, we found that MSX2 is also required for hPSC differentiation into MSCs through mesendoderm and trophoblast. Our findings provide novel mechanistic insights into lineage specification of hPSCs to MSCs and effective strategies for applications of stem cells for regenerative medicine.

PET/MR Imaging of Malondialdehyde-Acetaldehyde Epitopes With a Human Antibody Detects Clinically Relevant Atherothrombosis

BackgroundOxidation-specific epitopes (OSEs) are proinflammatory, and elevated levels in plasma predict cardiovascular events. ObjectivesThe purpose of this study was to develop novel positron emission tomography (PET) probes to noninvasively image OSE-rich lesions. MethodsAn antigen-binding fragment (Fab) antibody library was constructed from human fetal cord blood. After multiple rounds of screening against malondialdehyde-acetaldehyde (MAA) epitopes, the Fab LA25 containing minimal nontemplated insertions in the CDR3 region was identified and characterized. In mice, pharmacokinetics, biodistribution, and plaque specificity studies were performed with Zirconium-89 (89Zr)-labeled LA25. In rabbits, 89Zr-LA25 was used in combination with an integrated clinical PET/magnetic resonance (MR) system. 18F-fluorodeoxyglucose PET and dynamic contrast-enhanced MR imaging were used to evaluate vessel wall inflammation and plaque neovascularization, respectively. Extensive ex vivo validation was carried out through a combination of gamma counting, near infrared fluorescence, autoradiography, immunohistochemistry, and immunofluorescence. ResultsLA25 bound specifically to MAA epitopes in advanced and ruptured human atherosclerotic plaques with accompanying thrombi and in debris from distal protection devices. PET/MR imaging 24 h after injection of 89Zr-LA25 showed increased uptake in the abdominal aorta of atherosclerotic rabbits compared with nonatherosclerotic control rabbits, confirmed by ex vivo gamma counting and autoradiography. 18F-fluorodeoxyglucose PET, dynamic contrast-enhanced MR imaging, and near-infrared fluorescence signals were also significantly higher in atherosclerotic rabbit aortas compared with control aortas. Enhanced liver uptake was also noted in atherosclerotic animals, confirmed by the presence of MAA epitopes by immunostaining. Conclusions89Zr-LA25 is a novel PET radiotracer that may allow noninvasive phenotyping of high-risk OSE-rich lesions.

Presence of benzophenones commonly used as UV filters and absorbers in paired maternal and fetal samples

BackgroundPrevious studies have demonstrated widespread exposure of humans to certain benzophenones commonly used as UV filters or UV absorbers; some of which have been demonstrated to have endocrine disrupting abilities. ObjectivesTo examine whether benzophenones present in pregnant women pass through the placental barrier to amniotic fluid and further to the fetal blood circulation. MethodsA prospective study of 200 pregnant women with simultaneously collected paired samples of amniotic fluid and maternal serum and urine. In addition, unique samples of human fetal blood (n=4) obtained during cordocentesis: and cord blood (n=23) obtained at delivery, both with paired maternal samples of serum and urine collected simultaneously, were used. All biological samples were analyzed by TurboFlow-liquid chromatography - tandem mass spectrometry for seven different benzophenones. ResultsBenzophenone-1 (BP-1), benzophenone-3 (BP-3), 4-methyl-benzophenone (4-MBP), and 4-hydroxy-benzophenone (4-HBP) were all detectable in amniotic fluid and cord blood samples and except 4-HBP also in fetal blood; albeit at a low frequency. BP-1 and BP-3 were measured at ~10-times lower concentrations in fetal and cord blood compared to maternal serum and 1000-times lower concentration compared to maternal urine levels. Therefore BP-1 and BP-3 were only detectable in the fetal circulation in cases of high maternal exposure indicating some protection by the placental barrier. 4-MBP seems to pass into fetal and cord blood more freely with a median 1:3 ratio between cord blood and maternal serum levels. Only for BP-3, which the women seemed to be most exposed to, did the measured concentrations in maternal urine and serum correlate to concentrations measured in amniotic fluid. Thus, for BP-3, but not for the other tested benzophenones, maternal urinary levels seem to be a valid proxy for fetal exposure. ConclusionsDetectable levels of several of the investigated benzophenones in human amniotic fluid as well as in fetal and cord blood calls for further investigations of the toxicokinetic and potential endocrine disrupting properties of these compounds in order for better assessment of the risk to the developing fetus.

Human umbilical and fetal cerebral blood flow velocity waveforms following maternal glucose loading: a cross-sectional observational study.

Our aim was to study umbilical and fetal cerebral arterial blood flow velocity waveforms related to fetal biometric measures and maternal body mass index, glucose levels and parity following maternal oral glucose loading. The study had an experimental design in a cross-sectional observational study including 105 low-risk pregnancies (30-32weeks of gestation). Ultrasound Doppler measurements of umbilical and middle cerebral arterial (UA and MCA) velocity waveforms were performed before and at 2h after completed 75-g oral glucose tolerance tests (OGTT). We assessed changes in UA and MCA pulsatility indices (PI). MCA PI was significantly reduced following OGTT (p<0.001); these changes were not related to changes in fetal heart rate (r=-0.11, p=0.278). UA PI was also significantly reduced following OGTT (p=0.033); these changes were related to fetal heart rate (r=-0.47, p<0.001). This reduction was not significant (p=0.230) when the PI values were adjusted for fetal heart rate. The ratio MCA PI to UA PI was reduced (p=0.001). The effect of OGTT on MCA PI was not related to fetal abdominal circumference whereas the effect on the adjusted UA PI values was correlated to abdominal circumference (r=-0.20, p=0.045) but not to abdominal circumference Z-score (r=-0.16, p=0.115). The influence of OGTT on the Doppler parameters as well as heart rates was not related to prepregnant body mass index, glucose levels before or after OGTT, parity, fetal sex or gestational age. Maternal glucose loading seems to decrease fetal cerebral blood flow impedance independent of fetal size.

In response: Academic perspective.

In response: Academic perspective.

OP20.07: Human umbilical and fetal cerebral blood flow velocity waveforms following maternal glucose loading: a cross‐sectional observational study

OP20.07: Human umbilical and fetal cerebral blood flow velocity waveforms following maternal glucose loading: a cross‐sectional observational study

MRI reveals hemodynamic changes with acute maternal hyperoxygenation in human fetuses with and without congenital heart disease

Background Maternal hyperoxygenation (MH) has been used for intrauterine growth restriction and proposed as a way to improve ventricular growth in the setting of congenital heart disease (CHD)[1,2]. Fetal lamb experiments reveal increases in the SaO2 of umbilical venous (UV) blood and a reduction in pulmonary vascular resistance during MH [3]. Doppler suggests that MH increases the human fetal pulmonary blood flow (PBF) [4]. The combination of fetal phase contrast (PC) MRI and MR oximetry using T2 mapping offers the potential for a comprehensive hemodynamic assessment of late gestation fetal circulation [5]. We investigated the physiologic impact of MH in human fetuses with and without CHD using MRI to explore the potential therapeutic benefits of chronic MH.