Human Fetal Organs Research Articles

Development of a Generic Fetal Physiologically Based Pharmacokinetic Model and Prediction of Human Maternal and Fetal Organ Concentrations of Cefuroxime.

Physiologically based pharmacokinetic (PBPK) models for pregnant women have recently been successfully used to predict maternal and umbilical cord pharmacokinetics (PK). Because there is very limited opportunity for conducting clinical and PK investigations for fetal drug exposure, PBPK models may provide further insights. The objectives of this study were to extend a whole-body pregnancy PBPK model by multiple compartments representing fetal organs, and to predict the PK of cefuroxime in the maternal and fetal plasma, the amniotic fluid, and several fetal organs. To this end, a previously developed pregnancy PBPK model for cefuroxime was updated using the open-source software Open Systems Pharmacology (PK-Sim®/MoBi®). Multiple compartments were implemented to represent fetal organs including brain, heart, liver, lungs, kidneys, the gastrointestinal tract (GI), muscles, and fat tissue, as well as another compartment lumping organs and tissues not explicitly represented. This novel PBPK model successfully predicted cefuroxime concentrations in maternal blood, umbilical cord, amniotic fluid, and several fetal organs including heart, liver, and lungs. Further model validation with additional clinical PK data is needed to build confidence in the model. Being developed with an open-source software, the presented generic model can be freely re-used and tailored to address specific questions at hand, e.g., to assist the design of clinical studies in the context of drug research or to predict fetal organ concentrations of chemicals in the context of fetal health risk assessment.

Human pluripotent stem cell-derived inner ear organoids recapitulate otic development in vitro.

Our molecular understanding of the early stages of human inner ear development has been limited by the difficulty in accessing fetal samples at early gestational stages. As an alternative, previous studies have shown that inner ear morphogenesis can be partially recapitulated using induced pluripotent stem cells directed to differentiate into inner ear organoids (IEOs). Once validated and benchmarked, these systems could represent unique tools to complement and refine our understanding of human otic differentiation and model developmental defects. Here, we provide the first direct comparisons of the early human embryonic otocyst and fetal sensory organs with human IEOs. We use multiplexed immunostaining and single-cell RNA-sequencing to characterize IEOs at three key developmental steps, providing a new and unique signature of in vitro-derived otic placode, epithelium, neuroblasts and sensory epithelia. In parallel, we evaluate the expression and localization of crucial markers at these equivalent stages in human embryos. Together, our data indicate that the current state-of-the-art protocol enables the specification of bona fide otic tissue, supporting the further application of IEOs to inform inner ear biology and disease.

Pregnancy-related maternal physiological adaptations and fetal chemical exposure

Prenatal life represents a susceptible window of development during which chemical exposures can permanently alter fetal development, leading to an increased likelihood of disease later in life. Therefore, it is essential to assess exposure in the fetus. However, direct assessment in human fetuses is challenging, so most research measures maternal exposure. Pregnancy induces a range of significant physiological changes in women that may affect chemical metabolism and responses. Moreover, placental function, fetal sex, and pregnancy complications may further modify these exposures. The purpose of this narrative review is to give an overview of major pregnancy-related physiological changes, including placental function and impacts of pregnancy complications, to summarize existing studies assessing chemical exposure in human fetal organs, and to discuss possible interactions between physiological changes and exposures. Our review reveals major knowledge gaps in factors affecting fetal chemical exposure, highlighting the need to develop more sophisticated tools for chemical health risk assessment in fetuses.

Maternal exposure to ambient black carbon particles and their presence in maternal and fetal circulation and organs: an analysis of two independent population-based observational studies

SummaryBackgroundMaternal exposure to particulate air pollution during pregnancy has been linked to multiple adverse birth outcomes causing burden of disease later in the child's life. To date, there is a paucity of data on whether or not ambient particles can both reach and cross the human placenta to exert direct effects on fetal organ systems during gestation.MethodsIn this analysis, we used maternal-perinatal and fetal samples collected within the framework of two independent studies: the ENVIRONAGE (Environmental Influences on Ageing in Early Life) birth cohort of mothers giving birth at the East-Limburg Hospital in Genk, Belgium, and the SAFeR (Scottish Advanced Fetal Research) cohort of terminated, normally progressing pregnancies among women aged 16 years and older in Aberdeen and the Grampian region, UK. From the ENVIRONAGE study, we included 60 randomly selected mother-neonate pairs, excluding all mothers who reported that they ever smoked. From the SAFeR study, we included 36 fetuses of gestational age 7–20 weeks with cotinine concentrations indicative of non-smoking status. We used white light generation under femtosecond pulsed illumination to detect black carbon particles in samples collected at the maternal-fetal interface. We did appropriate validation experiments of all samples to confirm the carbonaceous nature of the identified particles.FindingsWe found evidence of the presence of black carbon particles in cord blood, confirming the ability of these particles to cross the placenta and enter the fetal circulation system. We also found a strong correlation (r ≥0·50; p<0·0001) between the maternal-perinatal particle load (in maternal blood [n=60], term placenta [n=60], and cord blood [n=60]) and residential ambient black carbon exposure during pregnancy. Additionally, we found the presence of black carbon particles in first and second trimester tissues (fetal liver [n=36], lung [n=36], and brain [n=14]) of electively terminated and normally progressing pregnancies from an independent study.InterpretationWe found that maternally inhaled carbonaceous air pollution particles can cross the placenta and then translocate into human fetal organs during gestation. These findings are especially concerning because this window of exposure is key to organ development. Further studies are needed to elucidate the mechanisms of particle translocation.FundingEuropean Research Council, Flemish Scientific Research Foundation, Kom op Tegen Kanker, UK Medical Research Council, and EU Horizon 2020.

Mixtures of persistent organic pollutants are found in vital organs of late gestation human fetuses

Persistent organic pollutants (POPs) are industrial chemicals with long half-lives. Early life exposure to POPs has been associated with adverse effects. Fetal exposure is typically estimated based on concentrations in maternal serum or placenta and little is known on the actual fetal exposure. We measured the concentrations of nine organochlorine pesticides (OCPs), ten polychlorinated biphenyl (PCB) congeners, and polybrominated diphenyl ether (PBDE) congeners by gas chromatography – tandem mass spectrometry in maternal serum, placenta, and fetal tissues (adipose tissue, liver, heart, lung and brain) in 20 pregnancies that ended in stillbirth (gestational weeks 36–41). The data were combined with our earlier data on perfluoroalkyl substances (PFASs) in the same cohort (Mamsen et al. 2019). HCB, p,p’-DDE, PCB 138 and PCB 153 were quantified in all samples of maternal serum, placenta and fetal tissues. All 22 POPs were detected in all fetal adipose tissue samples, even in cases where they could not be detected in maternal serum or placenta. Tissue:serum ratios were significantly higher in later gestations, male fetuses, and pregnancies with normal placental function. OCPs showed the highest tissue:serum ratios and PFAS the lowest. The highest chemical burden was found in adipose tissue and lowest in the brain. Overall, all studied human fetuses were intrinsically exposed to mixtures of POPs. Tissue:serum ratios were significantly modified by gestational age, fetal sex and placental function. Importantly, more chemicals were detected in fetal tissues compared to maternal serum and placenta, implying that these proxy samples may provide a misleading picture of actual fetal exposures.

Functional Specialization of Human Salivary Glands and Origins of Proteins Intrinsic to Human Saliva

Salivary proteins facilitate food perception and digestion, maintain the integrity of the mineralized tooth and oral epithelial surfaces, and shield the oro-digestive tract from environmental hazards and invading pathogens. Saliva, as one of the easiest to collect body fluids, also serves in diagnostic applications, with its proteins providing a window to body health. However, despite the availability of the human saliva proteome, the origins of individual proteins remain unclear. To bridge this gap, we analyzed the transcriptomes of 27 tissue samples derived from the three major types of human adult and fetal salivary glands and integrated these data with the saliva proteome and the proteomes and transcriptomes of 28+ other human organs, with tissue expression confirmed by 3D microscopy. Using these tools, we have linked saliva proteins to their source for the first time, an outcome with significant implications for basic research and diagnostic applications. Furthermore, our study represents the first comparative transcriptomic analysis of human adult and fetal exocrine organs, providing evidence that functional specialization occurs late in salivary gland development, and is driven mainly by the transcription of genes encoding secreted saliva proteins. Moreover, we found that dosage of abundant saliva proteins secreted by the salivary glands is primarily regulated at the transcriptional level, and that secreted proteins can be synthesized by distinct subsets of serous acinar cells, revealing hitherto unrecognized heterogeneity in the acinar cell lineage. Our results reveal the functional underpinnings of these secretory organs, paving the way for future investigations into saliva biology and pathology.

Alternative pathway androgen biosynthesis and human fetal female virilization

Androgen biosynthesis in the human fetus proceeds through the adrenal sex steroid precursor dehydroepiandrosterone, which is converted to testosterone in the gonads, followed by further activation to 5α-dihydrotestosterone in genital skin, thereby facilitating male external genital differentiation. Congenital adrenal hyperplasia due to P450 oxidoreductase deficiency results in disrupted dehydroepiandrosterone biosynthesis, explaining undervirilization in affected boys. However, many affected girls are born virilized, despite low circulating androgens. We hypothesized that this is due to a prenatally active, alternative androgen biosynthesis pathway from 17α-hydroxyprogesterone to 5α-dihydrotestosterone, which bypasses dehydroepiandrosterone and testosterone, with increased activity in congenital adrenal hyperplasia variants associated with 17α-hydroxyprogesterone accumulation. Here we employ explant cultures of human fetal organs (adrenals, gonads, genital skin) from the major period of sexual differentiation and show that alternative pathway androgen biosynthesis is active in the fetus, as assessed by liquid chromatography-tandem mass spectrometry. We found androgen receptor expression in male and female genital skin using immunohistochemistry and demonstrated that both 5α-dihydrotestosterone and adrenal explant culture supernatant induce nuclear translocation of the androgen receptor in female genital skin primary cultures. Analyzing urinary steroid excretion by gas chromatography-mass spectrometry, we show that neonates with P450 oxidoreductase deficiency produce androgens through the alternative androgen pathway during the first weeks of life. We provide quantitative in vitro evidence that the corresponding P450 oxidoreductase mutations predominantly support alternative pathway androgen biosynthesis. These results indicate a key role of alternative pathway androgen biosynthesis in the prenatal virilization of girls affected by congenital adrenal hyperplasia due to P450 oxidoreductase deficiency.

Concentrations of perfluoroalkyl substances (PFASs) in human embryonic and fetal organs from first, second, and third trimester pregnancies

BackgroundThe persistent environmental contaminants perfluoroalkyl substances (PFASs) have gained attention due to their potential adverse health effects, in particular following early life exposure. Information on human fetal exposure to PFASs is currently limited to one report on first trimester samples. There is no data available on PFAS concentrations in fetal organs throughout all three trimesters of pregnancy. MethodsWe measured the concentrations of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorohexane sulfonic acid (PFHxS) in human embryos and fetuses with corresponding placentas and maternal serum samples derived from elective pregnancy terminations and cases of intrauterine fetal death. A total of 78 embryos and fetuses aged 7–42 gestational weeks were included and a total of 225 fetal organs covering liver, lung, heart, central nervous system (CNS), and adipose tissue were analyzed, together with 71 placentas and 63 maternal serum samples. PFAS concentrations were assayed by liquid chromatography/triple quadrupole mass spectrometry. ResultsAll evaluated PFASs were detected and quantified in maternal sera, placentas and embryos/fetuses. In maternal serum samples, PFOS was detected in highest concentrations, followed by PFOA > PFNA > PFDA = PFUnA = PFHxS. Similarly, PFOS was detected in highest concentrations in embryo/fetal tissues, followed by PFOA > PFNA = PFDA = PFUnA. PFHxS was detected in very few fetuses. In general, PFAS concentrations in embryo/fetal tissue (ng/g) were lower than maternal serum (ng/ml) but similar to placenta concentrations. The total PFAS burden (i.e. the sum of all PFASs) was highest in lung tissue in first trimester samples and in liver in second and third trimester samples. The burden was lowest in CNS samples irrespective of fetal age. The placenta:maternal serum ratios of PFOS, PFOA and PFNA increased across gestation suggesting bioaccumulation in the placenta. Further, we observed that the ratios were higher in pregnancies with male fetuses compared to female fetuses. ConclusionsHuman fetuses were intrinsically exposed to a mixture of PFASs throughout gestation. The compounds were detected in all analyzed tissues, suggesting that PFASs reach and may affect many types of organs. Collectively, our results demonstrate that PFASs pass the placenta and deposit to embryo and fetal tissues, calling for risk assessment of gestational exposures.

Immunolocalization of VEGF/VEGFR system in human fetal vomeronasal organ during early development

The vomeronasal system (VNS) is an accessory olfactory structure present in most mammals adhibited to the detection of specific chemosignals implied in social and reproductive behavior. The VNS comprises the vomeronasal organ (VNO), vomeronasal nerve and accessory olfactory bulb. VNO is characterized by a neuroepithelium constituted by bipolar neurons and supporting and stem/progenitor cells. In humans, VNO is present during fetal life and is supposed to possess chemoreceptor activity and participate in gonadotropin-releasing hormone neuronal precursor migration toward the hypothalamus. Instead, the existence and functions of VNO in postnatal life is debated. Vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) have been demonstrated to play fundamental roles in various neurogenic events. However, there are no data regarding the localization and possible function of VEGF/VEGFRs in human fetal VNO. Therefore, this study was conceived to investigate the expression of VEGF/VEGFRs in human VNO in an early developmental period (9–12 weeks of gestation), when this organ appears well structured. Coronal sections of maxillofacial specimens were subjected to peroxidase-based immunohistochemistry for VEGF, VEGFR-1 and VEGFR-2. Double immunofluorescence for VEGF, VEGFR-1 or VEGFR-2 and the neuronal marker protein gene product 9.5 (PGP 9.5) was also performed. VEGF expression was evident in the entire VNO epithelium, with particularly strong reactivity in the middle layer. Strongly VEGF-immunostained cells with aspect similar to bipolar neurons and/or their presumable precursors were detected in the middle and basal layers. Cells detaching from the basal epithelial layer and detached cell groups in the surrounding lamina propria showed moderate/strong VEGF expression. The strongest VEGFR-1 and VEGFR-2 expression was detected in the apical epithelial layer. Cells with aspect similar to bipolar neurons and/or their presumable precursors located in the middle and basal layers and the detaching/detached cells displayed a VEGFR-1 and VEGFR-2 reactivity similar to that of VEGF. The basal epithelial layer exhibited stronger staining for VEGFRs than for VEGF. Cells with morphology and VEGF/VEGFR expression similar to those of the detaching/detached cells were also detected in the middle and basal VNO epithelial layers. Double immunofluorescence using anti-PGP 9.5 antibodies demonstrated that most of the VEGF/VEGFR-immunoreactive cells were neuronal cells. Collectively, our findings suggest that during early fetal development the VEGF/VEGFR system might be involved in the presumptive VNO chemoreceptor activity and neuronal precursor migration.

Three-dimensional imaging of the developing human fetal urogenital-genital tract: Indifferent stage to male and female differentiation

Recent studies in our lab have utilized three imaging techniques to visualize the developing human fetal urogenital tract in three dimensions: optical projection tomography, scanning electron microscopy and lightsheet fluorescence microscopy. We have applied these technologies to examine changes in morphology and differential gene expression in developing human external genital specimens from the ambisexual stage (<9 weeks fetal age) to well-differentiated male and female organs (>13 weeks fetal age). This work outlines the history and function of each of these three imaging modalities, our methods to prepare specimens for each and the novel findings we have produced thus far. We believe the images in this paper of human fetal urogenital organs produced using lightsheet fluorescence microscopy are the first published to date.

PD55-10 MACROSCOPIC WHOLE-MOUNTS CHARACTERIZING SEXUAL DIFFERENTIATION OF THE HUMAN FETAL UROGENITAL TRACT

You have accessJournal of UrologyBladder & Urethra: Anatomy, Physiology & Pharmacology II1 Apr 2018PD55-10 MACROSCOPIC WHOLE-MOUNTS CHARACTERIZING SEXUAL DIFFERENTIATION OF THE HUMAN FETAL UROGENITAL TRACT Joel Shen, Dylan S. Isaacson, Mei Cao, Adriane W. Sinclair, Gerald R. Cunha, and Laurence S. Baskin Joel ShenJoel Shen More articles by this author , Dylan S. IsaacsonDylan S. Isaacson More articles by this author , Mei CaoMei Cao More articles by this author , Adriane W. SinclairAdriane W. Sinclair More articles by this author , Gerald R. CunhaGerald R. Cunha More articles by this author , and Laurence S. BaskinLaurence S. Baskin More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2630AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES An appreciation of normal development of the male and female human urogenital tracts is required to understand congenital anomalies and their clinical implications. Herein we present macroscopic imaging of human fetal urogenital organs from 8 weeks (indifferent stage) to 21 weeks gestation (well differentiated). METHODS Fetal age of first and second trimester human fetal specimens was determined using heel-toe measurement. Gender was determined by Wolffian and Mullerian duct morphology and PCR for the Y chromosome. Length and width measurements from 3 unique specimens were taken at each time point from 8 to 22 weeks. RESULTS The external genitalia, reproductive tract, and gonads show distinct male and female features. External genitalia sex differentiation begins at 10 weeks and is complete at ~17 weeks. The clitoris is close to the size of the penis but lacks a distal urethra and remains close to the body wall. The male and female bladder grows similar in size during development with the male developing a prostate inferior to the bladder. The vas deferens, shown in the posterior view of the male bladder, inserts into the superior aspect of the prostate, medial to the ureters. In contrast to the male, the female reproductive tract is mostly derived from the midline uterovaginal canal (fused Müllerian ducts) and consists of the uterine tubes joining with the uterine body, the cervix and vagina. Gonad sex differentiation begins at 9 weeks at which the testis develops into an egg shape, while the ovary remains oblong. By ~16 weeks, the ovary surpasses the testis in length. Fetal lobulation of the kidney is first seen at ~12 weeks, and no sexual differences were observed. CONCLUSIONS Macroscopic imaging of the developing human fetus shows sex differences in the penis and clitoris, reproductive tract and gonads. The bladder and kidneys were identical in the sexes. Normal sexual differentiation allows an understanding of disorders of sex development. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e1060-e1061 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Joel Shen More articles by this author Dylan S. Isaacson More articles by this author Mei Cao More articles by this author Adriane W. Sinclair More articles by this author Gerald R. Cunha More articles by this author Laurence S. Baskin More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

VASCULOGENESIS PECULIARITIES OF THE INTRAMURAL PART OF COMMON BILE DUCT AT AN EARLY PERIOD OF HUMAN ONTOGENESIS

Morphological investigation of the peculiarities of structure and development of blood vessels of the intramural part of common bile duct (CBD) has been carried out on 72 series of histologic sections of embryos and 62 complexes of organs of human fetuses and newborns. It has been determined that since 7th week of intrauterine development period the origins of blood supply of CBD are anastomotic branches of posterior pancreato-duodenal arcade and anterior superior pancreato-duodenal artery partially. Germs of the definite structure of blood vessels of intramural part of CBD are identified as intramuscular and subepithelial vascular networks, situated around the basis of major duodenal papilla in fetuses 82,0-170,0 mm in parietal-coccygeal length.

DNA methylation and transcriptional trajectories during human development and reprogramming of isogenic pluripotent stem cells

Determining cell identity and maturation status of differentiated pluripotent stem cells (PSCs) requires knowledge of the transcriptional and epigenetic trajectory of organs during development. Here, we generate a transcriptional and DNA methylation atlas covering 21 organs during human fetal development. Analysis of multiple isogenic organ sets shows that organ-specific DNA methylation patterns are highly dynamic between week 9 (W9) and W22 of gestation. We investigate the impact of reprogramming on organ-specific DNA methylation by generating human induced pluripotent stem cell (hiPSC) lines from six isogenic organs. All isogenic hiPSCs acquire DNA methylation patterns comparable to existing hPSCs. However, hiPSCs derived from fetal brain retain brain-specific DNA methylation marks that seem sufficient to confer higher propensity to differentiate to neural derivatives. This systematic analysis of human fetal organs during development and associated isogenic hiPSC lines provides insights in the role of DNA methylation in lineage commitment and epigenetic reprogramming in humans.

Immunohistochemical verification of kisspeptins and their receptor in human fetal organs during prenatal development

Kisspeptins (KPs) and their receptor (KISS1R) play an important role in many physiological processes in the body, such as sexual maturation, reproductive system functioning, placentation, insulin secretion, and vasoconstriction. The highest level of kisspeptins and their receptor is observed in the organs of hypothalamic-pituitary-gonadal and hypothalamic-pituitary-adrenal axes, both in the form of mRNA and peptide. Kisspeptins are found in various body tissues: spinal cord (Dun et al., 2003), pancreas (Song et al., 2014), esophagus (Kostakis et al., 2013), adrenal glands and secretory system organs (Wahab et al., 2015), and in malignancies (Lee and Welch, 1997). However, the localization and the role of kisspeptins and their receptor in organs during fetal development have not yet been studied. At the same time, ample published data regarding the localization of kisspeptins and their receptors in human organs and tissues are discrepant, which requires the development of a standard staining technique. The modified technique presented in this paper made it possible to identify and evaluate the expression of kisspeptins and their receptor in human fetal organs at different stages of development. Kisspeptins and their receptors were found in all organs and tissues examined by us, but the degree of reaction was different. The highest level was observed in the hypothalamus material in the 28–32-week period, and the lowest amount of the protein was detected in the uterine material at all stages. Maximum level of KISS1R was detected in the pituitary material in the 36–40-week period. A correlation between gestational age and the level of kisspeptins in the ovaries, uterus, and adrenal glands was found: a significant increase in the amount of protein was detected. A significant increase in the amount of the kisspeptin receptor in pituitary, ovary, and uterus material was shown.

Concentration of perfluorinated compounds and cotinine in human foetal organs, placenta, and maternal plasma

BackgroundPerfluoroalkyl substances (PFASs) are bio-accumulative pollutants, and prenatal exposure to PFASs is believed to impact human foetal development and may have long-term adverse health effects later in life. Additionally, maternal cigarette smoking may be associated with PFAS levels. Foetal exposure has previously been estimated from umbilical cord plasma, but the actual concentration in foetal organs has never been measured. ObjectivesThe concentrations of 5 PFASs and cotinine – the primary metabolite of nicotine – were measured in human foetuses, placentas, and maternal plasma to evaluate to what extent these compounds were transferred from mother to foetus and to determine if the PFAS concentrations were associated with maternal cigarette smoking. MethodsThirty-nine Danish women who underwent legal termination of pregnancy before gestational week 12 were included; 24 maternal blood samples were obtained together with 34 placental samples and 108 foetal organs. PFASs and cotinine were assayed by liquid chromatography/triple quadrupole mass spectrometry. ResultsIn foetal organs, the average concentrations of perfluorooctanesulphonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFUnDa), and perfluorodecanoic acid (PFDA) were 0.6ng/g, 0.2ng/g, 0.1ng/g, 0.1ng/g, and 0.1ng/g, respectively. A significant positive correlation was found between the exposure duration, defined as foetal age, and foetal to maternal ratio for all five PFASs and cotinine. Smokers presented 99ng/g cotinine in plasma, 108ng/g in placenta, and 61ng/g in foetal organs. No correlation between the maternal cotinine concentrations and PFAS concentrations was found. ConclusionsPFASs were transferred from mother to foetus, however, with different efficiencies. The concentrations of PFOS, PFOA, PFNA, PFUnDA, and PFDA in foetal organs were much lower than the maternal concentrations. Furthermore, a significant correlation between the exposure duration and all of the evaluated PFASs was found. The health-compromising concentrations of these substances during foetal development are unknown.

Neurosensory Differentiation and Innervation Patterning in the Human Fetal Vestibular End Organs between the Gestational Weeks 8-12.

Balance orientation depends on the precise operation of the vestibular end organs and the vestibular ganglion neurons. Previous research on the assemblage of the neuronal network in the developing fetal vestibular organ has been limited to data from animal models. Insights into the molecular expression profiles and signaling moieties involved in embryological development of the human fetal inner ear have been limited. We present an investigation of the cells of the vestibular end organs with specific focus on the hair cell differentiation and innervation pattern using an uninterrupted series of unique specimens from gestational weeks 8–12. Nerve fibers positive for peripherin innervate the entire fetal crista and utricle. While in rodents only the peripheral regions of the cristae and the extra-striolar region of the statolithic organs are stained. At week 9, transcription factors PAX2 and PAX8 were observed in the hair cells whereas PAX6 was observed for the first time among the supporting cells of the cristae and the satellite glial cells of the vestibular ganglia. Glutamine synthetase, a regulator of the neurotransmitter glutamate, is strongly expressed among satellite glia cells, transitional zones of the utricle and supporting cells in the sensory epithelium. At gestational week 11, electron microscopic examination reveals bouton contacts at hair cells and first signs of the formation of a protocalyx at type I hair cells. Our study provides first-hand insight into the fetal development of the vestibular end organs as well as their pattern of innervation by means of immunohistochemical and EM techniques, with the aim of contributing toward our understanding of balance development.

Population Dynamics of MafA-Positive Cells During Ontogeny of Human Pancreas

Diverse transcription factors influencing cell differentiation are often chosen as markers of β cell progenitors. One of these transcription factors is MafA, which according to data in literature activates the expression of insulin gene in β cells. Other data support the hypothesis that MafA is required solely for the regulation of insulin secretion by β cells of adult islets and is not involved in the development of islet cells. In this paper, we study the role of MafA through both examination of human pancreas ontogeny and comparison of these data with dynamic changes in the population of insulin-positive and glucagon-positive cells. The aim of this research was the immunohistochemical analysis of MafA, insulin, and glucagon expression during human pancreas ontogeny. The research was conducted on whole embryos and isolated human fetal organs, obtained as a result of either miscarriage or legal medical abortion with voluntary consent of patients, and also on autopsy material from infant and adult human pancreas. As a result of this study, it was found that, during the ontogeny of human pancreas, the first MafA-positive cells appear in the islets at 12.5 weeks of gestation, that is, later than both insulin-positive cells (11.5 weeks of gestation) and glucagon-positive cells (8.5 weeks of gestation). No MafA-positive cells were found in the epithelium of pancreatic ducts. The number of MafA-positive cells in the islets increases during pancreatic organogenesis. The results of our research do not allow us to regard MafA as a marker of undifferentiated progenitors of islet cells. Based on this, we believe that the results obtained in this study are a supplementary contribution to the hypothesis that relates MafA to the markers of adult β cells.

Sex-specific divergence of antioxidant pathways in fetal brain, liver, and skeletal muscles

The sex-specific divergence of antioxidant pathways in fetal organs of opposite-sex twin is unknown and remains urgently in need of investigation. Such study faces many challenges, mainly the ethical impossibility of obtaining human fetal organs. Opposite-sex sheep twins represent a unique model for studying a sex dimorphism for antioxidant systems. The activity of total superoxide dismutase (SOD), SOD1, SOD2, glutathione peroxidase (GPX), glutathione reductase (GR) and catalase (CAT), the content of total glutathione, reduced glutathione (GSH), and oxidized glutathione (GSSG) were measured in brain, lung, liver, kidney, and skeletal muscles of female and male fetuses collected from sheep twin pregnancies at day 65 of gestation. Lipid peroxidation was assessed by measuring melondialdehyde (MDA) tissue content. Male brain has greater total SOD and SOD1 activities than female brain. Female liver has greater SOD2 activity than male liver. Male liver has greater GR activity than female liver. Male liver has higher total GSH and GSSG content than female liver. Male skeletal muscles have higher total GSH, GSH, and GSSG content than female skeletal muscles. Female brain and liver have higher MDA content than male brain and liver. This is the first report of a sex dimorphism for fetal organ antioxidative pathways. Brain, liver, and skeletal muscles of male and female fetuses display distinct antioxidant pathways. Such sexually dimorphic responses to early life oxidative stress might be involved in the sex-related difference in fetal development that may have a long-term effect on offspring. Our study urges researchers to take into consideration the importance of sex as a biologic variable in their investigations.

Evaluating the potential effect on fetal tissue after exposure to granisetron during pregnancy.

The objective of this study was to elucidate the possible toxic effects on the fetal tissues after exposure to two clinically relevant concentrations of granisetron. Primary cells were isolated from human fetal organs of 16-19 weeks gestational age and treated with 3 ng/mL or 30 ng/mL of granisetron. Cell cycle progression was evaluated by flow cytometry. ELISA was used to detect alterations in major apoptotic proteins. Up to 10% apoptosis in cardiac tissue was observed following treatment with 30 ng/mL granisetron. Neither concentration of granisetron caused alteration in cell cycle progression or alterations in apoptotic proteins in any of the other tissues. At 30 ng/mL granisetron concentration had the potential to induce up to 10% apoptosis in cardiac tissue; clinical significance needs further evaluation. At granisetron 3 ng/mL there was no detectable toxicity or on any fetal tissue in this study. Further research is needed to confirm these preliminary findings and determine if clinically significant.

Muc5ac mucin expression during rat skin development.

Some mucin genes have been detected during human embryonic and fetal organ development; however, little is known about mucin expression in epidermal development, neither in humans nor in other species. The present research was developed to explore Muc5ac skin expression during pre- and post-natal rat development. Immunohistochemistry (IHC), Western blotting (WB) and RT-PCR were employed. By IHC, Muc5ac protein was found early in embryonic epidermis from day 13 of gestation until seven days after birth when the surface epidermis became negative and the reaction was restricted to secreting sebum cells. In coincidence with IHC findings, WB analysis showed a band at approximately 200KDa at the same periods of development. Results were also confirmed by RT-PCR.Muc5ac expression in rat embryonic epidermis suggests that Muc5ac may play a protective role in embryonic skin previous to birth which may be replaced by pile covering. To our knowledge, this is the first report that confirmed Muc5ac expression during skin development.