Clustered synapses develop in distinct dendritic domains in visual cortex before eye opening.

Synaptic inputs to cortical neurons are highly structured in adult sensory systems, such that neighboring synapses along dendrites are activated by similar stimuli. This organization of synaptic inputs, called synaptic clustering, is required for high-fidelity signal processing, and clustered synapses can already be observed before eye opening. However, how clustered inputs emerge during development is unknown. Here, we employed concurrent in vivo whole-cell patch-clamp and dendritic calcium imaging to map spontaneous synaptic inputs to dendrites of layer 2/3 neurons in the mouse primary visual cortex during the second postnatal week until eye opening. We found that the number of functional synapses and the frequency of transmission events increase several fold during this developmental period. At the beginning of the second postnatal week, synapses assemble specifically in confined dendritic segments, whereas other segments are devoid of synapses. By the end of the second postnatal week, just before eye opening, dendrites are almost entirely covered by domains of co-active synapses. Finally, co-activity with their neighbor synapses correlates with synaptic stabilization and potentiation. Thus, clustered synapses form in distinct functional domains presumably to equip dendrites with computational modules for high-capacity sensory processing when the eyes open.

Moderate Prenatal Alcohol Exposure Increases Toll-like Receptor Activity in Umbilical Cord Blood at Birth: A Pilot Study.

The prevalence of prenatal alcohol exposure (PAE) is increasing, with evidence suggesting that PAE is linked to an increased risk of infections. PAE is hypothesized to affect the innate immune system, which identifies pathogens through pattern recognition receptors, of which toll-like receptors (TLRs) are key components. We hypothesized that light-to-moderate PAE would impair immune responses, as measured by a heightened response in cytokine levels following TLR stimulation. Umbilical cord samples (10 controls and 8 PAE) from a subset of the Ethanol, Neurodevelopment, Infant and Child Health Study-2 cohort were included. Peripheral blood mononuclear cells (PMBCs) were stimulated with one agonist (TLR2, TLR3, TLR4, or TLR9). TLR2 agonist stimulation significantly increased pro-inflammatory interleukin-1-beta in the PAE group after 24 h. Pro- and anti-inflammatory cytokines were increased following stimulation with the TLR2 agonists. Stimulation with TLR3 or TLR9 agonists displayed minimal impact overall, but there were significant increases in the percent change of the control compared to PAE after 24 h. The results of this pilot investigation support further work into the impact on TLR2 and TLR4 response following PAE to delineate if alterations in levels of pro- and anti-inflammatory cytokines have clinical significance that could be used in patient management and/or attention to follow-up.

Modeling the human placenta: in vitro applications in developmental and reproductive toxicology.

During its temporary tenure, the placenta has extensive and specialized functions that are critical for pre- and post-natal development. The consequences of chemical exposure in utero can have profound effects on the structure and function of pregnancy-associated tissues and the life-long health of the birthing person and their offspring. However, the toxicological importance and critical functions of the placenta to embryonic and fetal development and maturation have been understudied. This narrative will review early placental development in humans and highlight some in vitro models currently in use that are or can be applied to better understand placental processes underlying developmental toxicity due to in utero environmental exposures.

In Utero Gene Therapy and its Application in Genetic Hearing Loss.

For monogenic genetic diseases, in utero gene therapy (IUGT) shows the potential for early prevention against irreversible and lethal pathological changes. Moreover, animal models have also demonstrated the effectiveness of IUGT in the treatment of coagulation disorders, hemoglobinopathies, neurogenetic disorders, and metabolic and pulmonary diseases. For major alpha thalassemia and severe osteogenesis imperfecta, in utero stem cell transplantation has entered the phase I clinical trial stage. Within the realm of the inner ear, genetic hearing loss significantly hampers speech, cognitive, and intellectual development in children. Nowadays, gene therapies offer substantial promise for deafness, with the success of clinical trials in autosomal recessive deafness 9 using AAV-OTOF gene therapy. However, the majority of genetic mutations that cause deafness affect the development of cochlear structures before the birth of fetuses. Thus, gene therapy before alterations in cochlear structure leading to hearing loss has promising applications. In this review, addressing advances in various fields of IUGT, the progress, and application of IUGT in the treatment of genetic hearing loss are focused, in particular its implementation methods and unique advantages.

Intestinal flora and pregnancy complications: Current insights and future prospects.

Numerous studies have demonstrated the pivotal roles of intestinal microbiota in many physiopathological processes through complex interactions with the host. As a unique period in a woman's lifespan, pregnancy is characterized by changes in hormones, immunity, and metabolism. The gut microbiota also changes during this period and plays a crucial role in maintaining a healthy pregnancy. Consequently, anomalies in the composition and function of the gut microbiota, namely, gut microbiota dysbiosis, can predispose individuals to various pregnancy complications, posing substantial risks to both maternal and neonatal health. However, there are still many controversies in this field, such as "sterile womb" versus "in utero colonization." Therefore, a thorough understanding of the roles and mechanisms of gut microbiota in pregnancy and its complications is essential to safeguard the health of both mother and child. This review provides a comprehensive overview of the changes in gut microbiota during pregnancy, its abnormalities in common pregnancy complications, and potential etiological implications. It also explores the potential of gut microbiota in diagnosing and treating pregnancy complications and examines the possibility of gut-derived bacteria residing in the uterus/placenta. Our aim is to expand knowledge in maternal and infant health from the gut microbiota perspective, aiding in developing new preventive and therapeutic strategies for pregnancy complications based on intestinal microecology.

From bedside to bench: New insights in epilepsy-associated tumors based on recent classification updates and animal models on brain tumor networks.

Low-grade neuroepithelial tumors (LGNTs), particularly those with glioneuronal histology, are highly associated with pharmacoresistant epilepsy. Increasing research focused on these neoplastic lesions did not translate into drug discovery; and anticonvulsant or antitumor therapies are not available yet. During the last years, animal modeling has improved, thereby leading to the possibility of generating brain tumors in mice mimicking crucial genetic, molecular and immunohistological features. Among them, intraventricular in utero electroporation (IUE) has been proven to be a valuable tool for the generation of animal models for LGNTs allowing endogenous tumor growth within the mouse brain parenchyma. Epileptogenicity is mostly determined by the slow-growing patterns of these tumors, thus mirroring intrinsic interactions between tumor cells and surrounding neurons is crucial to investigate the mechanisms underlying convulsive activity. In this review, we provide an updated classification of the human LGNT and summarize the most recent data from human and animal models, with a focus on the crosstalk between brain tumors and neuronal function.

Autoantigen Exposure in Murine Fetuses Elicited Nonpathogenic Autoimmunity.

BACKGROUND AND AIM: Autoimmunity refers to the presence of autoantibodies and autoreactive lymphocytes against the structural molecules of an individual's cells or tissues, known as self-antigens or autoantigens. It might exist in the absence of autoimmune disease. However, how autoimmunity develops remains a mystery, despite the discovery of autoantibodies in human cord blood. METHODS: Murine fetuses on day 14 of gestation were subjected to intraperitoneal injection of murine thyroid peroxidase (TPO) peptides or collagen type II (CII) at graded doses via transuterine approach. Postnatally, the recipients were examined for autoantibodies by ELISA and autoreactive lymphocytes by in vitro incorporation of tritium and for the development of autoimmune thyroiditis or arthritis. RESULTS: At one month of age, the recipients did not secrete significant levels of anti-TPO or CII IgG2a in sera until a dose of 0.5 µg TPO or 5.0 µg CII was injected in utero. Serum anti-TPO or CII IgG2a persisted for at least two to four months postnatally. In recipients with elevated autoantibodies, their lymphocytes also showed proliferative responses specifically to TPO or CII. However, the development of autoantibodies and autoreactive lymphocytes was not associated with inflammatory cell infiltration of thyroid glands or paw joints even though anti-TPO or CII IgG2a was enhanced by postnatal TPO or CII challenge. CONCLUSION: Fetal exposure to free autoantigens could be immunogenic, shedding new light on the in utero origin of autoantibodies and autoreactive lymphocytes. The development of autoimmunity requires a threshold intensity of autoantigen exposure in the fetus.

In Utero Exposure to Maternal SARS-CoV-2 Infection Is Associated With Higher Left Ventricular Mass in Toddlers.

The intrauterine environment plays a critical role in shaping chronic disease risk over the life course. We prospectively evaluated cardiometabolic outcomes in toddlers born to mothers with versus without prenatal severe acute respiratory syndrome coronavirus 2 infection. Children with in utero severe acute respiratory syndrome coronavirus 2 exposure had higher left ventricular mass in association with altered maternal immunologic indices.

Advances in Fetal Brain Imaging.

Over the last 20 years, there have been remarkable developments in fetal brain MR imaging analysis methods. This article delves into the specifics of structural imaging, diffusion imaging, functional MR imaging, and spectroscopy, highlighting the latest advancements in motion correction, fetal brain development atlases, and the challenges and innovations. Furthermore, this article explores the clinical applications of these advanced imaging techniques in comprehending and diagnosing fetal brain development and abnormalities.

Phosphaturia in HIV-exposed Uninfected Neonates Associated with Maternal Use of Tenofovir Disoproxil Fumarate in Late Pregnancy.

BACKGROUND: Tenofovir disoproxil fumarate (TDF) is often used in treating pregnant women living with HIV. Third trimester TDF exposure is associated with a 12% reduction in bone mineral content in HIV-exposed uninfected (HEU) neonates. Potential mechanisms underlying this observation are unknown. METHODS: The TDF study enrolled newborns of gestational age ≥36 weeks from the Surveillance Monitoring for Antiretroviral Therapy and Toxicities study based on in utero TDF exposure (TDF use ≥8 weeks in third trimester versus none). Blood and urine samples were collected cross-sectionally within 30 days of birth to assess renal function (serum creatinine, serum phosphate, eGFR, percent tubular reabsorption of phosphate [PTRP]), and bone turnover (serum parathyroid hormone, 25-OH vitamin D [25(OH)D], and urinary cross-linked N-telopeptide of type 1 collagen). For each biomarker, a LOESS plot was fit using values at age at specimen collection; regression lines over age were fit among samples collected from 4-30 days, to compare slopes by TDF exposure. RESULTS: Among 141 neonates, 77 were TDF-exposed and 64 TDF-unexposed. Between age 4 and 30 days, PTRP decreased more rapidly in the TDF-exposed compared to the unexposed group with slopes of -0.58 versus -0.08/day (difference -0.50/day [95%CI -0.88, -0.11]). Slopes for 25(OH)D were similar in both groups, but serum levels lower in TDF-exposed neonates (median [IQR]: 22 [19, 29] versus 26 [22,37] ng/mL). No differences were observed for other biomarkers. CONCLUSIONS: Third trimester in utero exposure to TDF is associated with increased urinary loss of phosphate and lower serum concentrations of 25(OH)D in HEU neonates.

Post-transcriptional (re)programming of B lymphocyte development: From bench to bedside?

Hematopoiesis, a process which generates blood and immune cells, changes significantly during mammalian development. Definitive hematopoiesis is marked by the emergence of long-term hematopoietic stem cells (HSCs). Here, we will focus on the post-transcriptional differences between fetal liver (FL) and adult bone marrow (ABM) HSCs. It remains unclear how or why exactly FL HSCs transition to ABM HSCs, but we aim to leverage their differences to revive an old idea: in utero HSC transplantation. Unexpectedly, the expression of certain RNA-binding proteins (RBPs) play an important role in HSC specification, and can be employed to convert or reprogram adult HSCs back to a fetal-like state. Among other features, FL HSCs have a broad differentiation capacity that includes the ability to regenerate both conventional B and T cells, as well as innate-like or unconventional lymphocytes such as B-1a and marginal zone B (MzB) cells. This chapter will focus on RNA binding proteins, namely LIN28B and IGF2BP3, that are expressed during fetal life and how they promote B-1a cell development. Furthermore, this chapter considers a potential clinical application of synthetic co-expression of LIN28B and IGF2BP3 in HSCs.

DNA methylation signatures of youth-onset type 2 diabetes and exposure to maternal diabetes.

OBJECTIVE: Youth-onset type 2 diabetes (T2D) is physiologically distinct from adult-onset, but it is not clear how the two diseases differ at a molecular level. In utero exposure to maternal type 2 diabetes (T2D) is known to be a specific risk factor for youth-onset T2D. DNA methylation (DNAm) changes associated with T2D but which differ between youth- and adult-onset might delineate the impacts of T2D development at different ages and could also determine the contribution of exposure to in utero diabetes. METHODS: We performed an epigenome-wide analysis of DNAm on whole blood from 218 youth with T2D and 77 normoglycemic controls from the iCARE (improving renal Complications in Adolescents with type 2 diabetes through REsearch) cohort. Associations were tested using multiple linear regression models while adjusting for maternal diabetes, sex, age, BMI, smoking status, second-hand smoking exposure, cell-type proportions and genetic ancestry. RESULTS: We identified 3830 differentially methylated sites associated with youth T2D onset, of which 3794 were moderately (adjusted p-value < 0.05 and effect size estimate > 0.01) associated and 36 were strongly (adjusted p-value < 0.05 and effect size estimate > 0.05) associated. A total of 3725 of these sites were not previously reported in the EWAS Atlas as associated with T2D, adult obesity or youth obesity. Moreover, three CpGs associated with youth-onset T2D in the PFKFB3 gene were also associated with maternal T2D exposure (FDR < 0.05 and effect size > 0.01). This is the first study to link PFKFB3 and T2D in youth. CONCLUSION: Our findings support that T2D in youth has different impacts on DNAm than adult-onset, and suggests that changes in DNAm could provide an important link between in utero exposure to maternal diabetes and the onset of T2D.

Enhancing fetal outcomes in GCK-MODY pregnancies: a precision medicine approach via non-invasive prenatal GCK mutation detection.

Background: Mutations in the GCK gene cause Maturity Onset Diabetes of the Young (GCK-MODY) by impairing glucose-sensing in pancreatic beta cells. During pregnancy, managing this type of diabetes varies based on fetal genotype. Fetuses carrying a GCK mutation can derive benefit from moderate maternal hyperglycemia, stimulating insulin secretion in fetal islets, whereas this may cause macrosomia in wild-type fetuses. Modulating maternal glycemia can thus be viewed as a form of personalized prenatal therapy, highly beneficial but not justifying the risk of invasive testing. We therefore developed a monogenic non-invasive prenatal diagnostic (NIPD-M) test to reliably detect the transmission of a known maternal GCK mutation to the fetus. Methods: A small amount of fetal circulating cell-free DNA is present in maternal plasma but cannot be distinguished from maternal cell-free DNA. Determining transmission of a maternal mutation to the fetus thus implies sequencing adjacent polymorphisms to determine the balance of maternal haplotypes, the transmitted haplotype being over-represented in maternal plasma. Results: Here we present a series of such tests in which fetal genotype was successfully determined and show that it can be used to guide therapeutic decisions during pregnancy and improve the outcome for the offspring. We discuss several potential hurdles inherent to the technique, and strategies to overcome these. Conclusion: Our NIPD-M test allows reliable determination of the presence of a maternal GCK mutation in the fetus, thereby allowing personalized in utero therapy by modulating maternal glycemia, without incurring the risk of miscarriage inherent to invasive testing.

Association between radiation dose, thyroid hormone, and IQ levels in children exposed to radiation in utero after the Chernobyl accident.

Few studies have explored the effects of n utero radiation exposure on human health and cognition and none have taken into account thyroid hormone levels (T3), which have shown to affect cognitive performance. We investigated mechanisms of possible radiation effects on IQ in two cohorts of 250 persons each: exposed n utero after the Chernobyl accident: a 'higher exposure group (HEG)', whose mothers resided in more heavily contaminated territories at the time of the Chernobyl accident, and a 'lesser exposure group (LEG)' whose mothers resided in less contaminated areas. The dataset included information on estimated prenatal thyroid radiation dose, gestation week at the time of the accident (ATA); thyroid hormones: T3 (triiodothyronine) and T4 (thyroxine) levels measured at age 11-12 years and general IQ measured at three time points: t1: 6-7 years old; t2: 11-12 years old and t3: 15-16 years old. Descriptive and inference analyses were used to explore the dynamic of changes through time and the associations between key variables at the three time points. Estimated radiation doses to the thyroid gland were substantially higher in the HEG than in the LEG (mean 391 vs 25 mGy respectively). Significant differences in thyroid hormones levels were observed between the two groups, with lower values in T3 (higher in T4) in the LEG. At t1, the general IQ, as well as verbal and non-verbal IQ scores, were lower in the HEG than in the LEG. In the HEG, analyses adjusting simultaneously for radiation dose, gestational week ATA and T3 levels suggest that all three variables are associated with IQ, with the latter being highest among those exposed later during gestation and decreasing with increasing level of dose and of T3. No significant association was observed between IQ and T4 levels. No effect of exposure on IQ was seen in the LEG. Further investigation of this hypothesis will be important to understand the relation between n utero exposure radiation dose to thyroid, thyroid hormone levels and IQ, taking into account effects of potential confounding factors (physiological stress, maternal anxiety related evacuation).

We followed up persons exposed in utero to radiation from the Chernobyl accidentAmong the most highly exposed, IQ was higher among those exposed later during gestationAmong the most highly exposed, IQ also decreased with increasing level of dose and of T3No such relation was seen in those with lower exposureOur study provides insights into the possible relation between prenatal radiation dose and IQ and the factors which may modify it.

In Utero Mother-to-Child Transmission of HIV-1 and the Associated Factors in Rwanda, Africa.

Mother-to-child transmission (MTCT) of HIV-1 and associated mortality continue to occur at unacceptably high rates, despite the extensive rollout and implementation of Prevention of Mother-to-Child Transmission (PMTCT) Programs, including the modified versions of Option B and B+ in 2010 and 2012, respectively. Maternal HIV viral load (VL) and socio-behavioral factors sustaining MTCT in Rwanda remain largely unexplored. The study examined the effects of socio-behavioral factors on maternal VL and their contribution to in utero transmission of HIV-1 in the context of Rwanda's HIV epidemic. A prospective cohort study was conducted in 862 mother-baby pairs enrolled in 10 PMTCT clinics in Rwanda. VL was determined on plasma and Dried Blood Spots samples, whereas HIV DNA PCR was performed to determine in utero MTCT of HIV of the babies immediately at birth and then at 3 weeks, 4 weeks, 6 months, and 18 months, together with HIV antibody testing to determine other forms of MTCT of HIV. Quantitative data on socio-behavioral factors were collected through a structured questionnaire. Linear regression and univariate analysis of variances using SPSS 25.0 were used to test the hypotheses. We found 22/862 (2.55%) cases of in utero transmission and a total of 32/862 (3.7%) cases of MTCT of HIV-1 over 18 study months. Maternal VL at delivery was significantly associated with the risk of in utero transmission of HIV-1. Socio-behavioral factors associated with elevated maternal VL at delivery included alcohol, smoking, multiple sexual partners, mothers' income, being a casual laborer, and distance to health care services. We report an MTCT rate of 3.7% in our study population over the 18 months, higher than the national average of 1.5%, the majority of which occurred in utero. MTCT cases were attributable to failure to suppress maternal VL.

Programming effects of intrauterine hyperthermia on adrenal gland development.

Maternal heat stress during late pregnancy can lead to intrauterine hyperthermia and affect fetal hypothalamic-pituitary-adrenal axis development and function. Herein, we investigated the effects of chronic environmental heat stress exposure of Holstein cows in the last 2 mo of gestation on their offspring's adrenal gland histomorphology and transcriptome. Cows in their last 54 ± 5 d of gestation were either heat-stressed (i.e., housed under the shade of a free stall barn) or provided heat-stress abatement via active cooling (i.e., via water soakers and fans) during a subtropical summer (Temperature-Humidity Index >68). Respiration rate (RR) and skin temperature (ST) were elevated in heat-stressed dams relative to the cows with access to heat abatement (23 bpm and 2 ◦C higher for RR and ST, respectively). Heifers born to heat-stressed cows experienced heat stress in utero (HS), while heifers born to actively cooled cows did not (CL). The adrenal gland was harvested from 6 heifers per group that were euthanized at birth (d 0; n = 12) or one week after weaning (d 63; n = 12). Circulating cortisol was measured from blood samples collected weekly throughout the pre-weaning period. At d 63, heifers that experienced HS while developing in utero had heavier adrenal glands, with a greater total tissue surface area and thickness of the zona glomerulosa (ZG), fasciculata (ZF), and reticularis (ZR), compared with CL heifers. In addition, the adrenal gland of in utero HS heifers had less cells in the ZG, more and larger cells in the ZF and larger cells in the ZR, relative to CL heifers. Although no changes in circulating cortisol were observed through the pre-weaning period, the transcriptomic profile of the adrenal tissue was altered by fetal exposure to hyperthermia. Both at birth and on d 63, approximately 30 pathways were differentially expressed in the adrenal glands of in utero HS heifers relative to CL. These pathways were associated with immune function, inflammation, prolactin signaling, cell function, and calcium transport. Upstream regulators significantly activated or inhibited in the adrenal glands of heifers exposed to intrauterine hyperthermia were identified. Maternal exposure to heat stress during late gestation caused an enlargement of their offspring's adrenal glands by inducing ZG and ZF cell hypertrophy, and caused gene expression changes. These phenotypic, histological, and molecular changes in the adrenal gland might lead to alterations in stress, immune, and metabolic responses later in life.

Estimating the dynamic early life exposure to PFOA and PFOS of the HELIX children: Emerging profiles via prenatal exposure, breastfeeding, and diet.

In utero and children's exposure to per- and polyfluoroalkyl substances (PFAS) is a major concern in health risk assessment as early life exposures are suspected to induce adverse health effects. Our work aims to estimate children's exposure (from birth to 12 years old) to PFOA and PFOS, using a Physiologically-Based Pharmacokinetic (PBPK) modelling approach. A model for PFAS was updated to simulate the internal PFAS exposures during the in utero life and childhood, and including individual characteristics and exposure scenarios (e.g., duration of breastfeeding, weight at birth, etc.). Our approach was applied to the HELIX cohort, involving 1,239 mother-child pairs with measured PFOA and PFOS plasma concentrations at two sampling times: maternal and child plasma concentrations (6 to 12 y.o). Our model predicted an increase in plasma concentrations during fetal development and childhood until 2 y.o when the maximum concentrations were reached. Higher plasma concentrations of PFOA than PFOS were predicted until 2 y.o, and then PFOS concentrations gradually became higher than PFOA concentrations. From 2 to 8 y.o, mean concentrations decreased from 3.1 to 1.88 µg/L or ng/mL (PFOA) and from 4.77 to 3.56 µg/L (PFOS). The concentration-time profiles vary with the age and were mostly influenced by in utero exposure (on the first 4 months after birth), breastfeeding (from 5 months to 2 (PFOA) or 5 (PFOS) y.o of the children), and food intake (after 3 (PFOA) or 6 (PFOS) y.o of the children). Similar measured biomarker levels can correspond to large differences in the simulated internal exposures, highlighting the importance to investigate the children's exposure over the early life to improve exposure classification. Our approach demonstrates the possibility to simulate individual internal exposures using PBPK models when measured biomarkers are scarce, helping risk assessors in gaining insight into internal exposure during critical windows, such as early life.

Live Imaging of Migrating Neurons and Glial Progenitors Visualized by in Utero Electroporation.

During cortical development, both neurons and glial cells are generated in the germinal zone near the lateral ventricle, migrate in the correct direction, and settle in their appropriate locations. This developmental process can be clearly visualized by introducing fluorescent protein-expression vectors via in utero electroporation. In this chapter, we describe labeling methods for migrating neurons and glial progenitors, as well as methods for slice culture, and time-lapse imaging.

Brain Sample Preparation After Performing in Utero Electroporation to Proliferating and Differentiated Cells in the Developing Mouse Neocortex.

In utero electroporation (IUE) enables labeling and manipulating specific types of cells by introducing DNA plasmids with desired promoters. After the surgery, mouse brains are fixed at any stage and analyzed after staining using specific antibodies. Here, we describe the flow of the IUE experiment from the preparation to microscopic observations.