Sequencing Cell-free Fetal DNA in Pregnant Women With GCK-MODY.

CONTEXT: Individuals with monogenic diabetes due to inactivating glucokinase (GCK) variants typically do not require treatment, except potentially during pregnancy. In pregnancy, fetal GCK genotype determines whether treatment is indicated, but noninvasive methods are not clinically available. OBJECTIVE: This work aims to develop a method to determine fetal GCK genotype noninvasively using maternal cell-free fetal DNA. METHODS: This was a proof-of-concept study involving 3 pregnant women with a causal GCK variant that used information from 1) massive parallel sequencing of maternal plasma cell-free DNA, 2) direct haplotype sequences of maternal genomic DNA, and 3) the paternal genotypes to estimate relative haplotype dosage of the pathogenic variant-linked haplotype. Statistical testing of variant inheritance was performed using a sequential probability ratio test (SPRT). RESULTS: In each of the 3 cases, plasma cell-free DNA was extracted once between gestational weeks 24 and 36. The fetal fraction of cell-free DNA ranged from 21.8% to 23.0%. Paternal homozygous alleles that were identical to the maternal GCK variant-linked allele were not overrepresented in the cell-free DNA. Paternal homozygous alleles that were identical to the maternal wild-type-linked allele were significantly overrepresented. Based on the SPRT, we predicted that all 3 cases did not inherit the GCK variant. Postnatal infant genotyping confirmed our prediction in each case. CONCLUSION: We have successfully implemented a noninvasive method to predict fetal GCK genotype using cell-free DNA in 3 pregnant women carrying an inactivating GCK variant. This method could guide tailoring of hyperglycemia treatment in pregnancies of women with GCK monogenic diabetes.

Human Fetal Liver Metabolism of Oxycodone Is Mediated by CYP3A7.

Oxycodone is an opioid analgesic that is commonly prescribed to pregnant women to treat moderate-to-severe pain. It has been shown to cross the placenta and distribute to the fetus. Oxycodone is mainly metabolized by CYP3A4 in the adult liver. Since CYP3A7 is abundantly expressed in the fetal liver and has overlapping substrate specificity with CYP3A4, we hypothesized that the fetal liver may significantly limit fetal exposure to oxycodone. This study showed that oxycodone is metabolized by CYP3A7 to noroxycodone in fetal liver microsomes (FLMs). The measured CYP3A7 expression was 191-409 pmol/mg protein in 14 FLMs, and an intersystem extrapolation factor (ISEF) for CYP3A7 was 0.016-0.066 in the panel of fetal livers using 6ß-OH-testosterone formation as the probe reaction. Noroxycodone formation in the fetal liver was predicted from formation rate by recombinant CYP3A7, CYP3A7 expression level and the established ISEF value with average fold error of 1.25. Based on the intrinsic clearance of oxycodone measured in FLM, the fetal hepatic clearance (CLh) at term was predicted to be 495 (range: 66.4-936) µL/min, a value that is > 99% lower than the predicted adult liver CLh. The predicted fetal hepatic extraction ratio was 0.0019 (range: 0.00003-0.0036). These results suggest that fetal liver metabolism does not quantitatively contribute to the total systemic clearance of oxycodone in pregnant women nor does it provide a barrier for limiting fetal exposure to oxycodone. Additionally, since CYP3A7 forms noroxycodone, an inactive metabolite, the metabolism in the fetal liver is unlikely to affect fetal opioid activity.

Protein expression of angiotensin-converting enzyme 2, a SARS-CoV-2-specific receptor, in fetal and placental tissues throughout gestation: new insight for perinatal counseling.

OBJECTIVE: Pregnant women can be infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), yet the incidence of perinatal infection is low. We hypothesized that this could be related to low expression of the membrane receptor for SARS-CoV-2, angiotensin-converting enzyme 2 (ACE2), in the fetoplacental unit. We evaluated protein expression of ACE2 at various gestational ages in both placentae and fetal organs from pregnancies not infected with SARS-CoV-2. METHODS: In May 2020, using samples from a registered biobank, we performed immunohistochemical analysis for ACE2 in tissue samples from fetal organs and placentae from five cases of second- or third-trimester medical termination of pregnancy in healthy women (performed between 15 and 38 weeks' gestation), as well as a further two placentae, one from a 7-week spontaneous miscarriage in a non-infected woman and one from a symptomatic pregnant woman positive for SARS-CoV-2 delivered by Cesarean section at 34 weeks. Samples were paraffin-embedded and organ tissues included kidney, brain, lung, intestinal tract, heart and testis. Matching tissues (kidney, intestinal tract, lung and testis) from autopsies of four 8-year-old children were tested as controls. Tissue sections were incubated with rabbit monoclonal anti-ACE2, and protein expression of ACE2 was detected by immunohistochemistry. RESULTS: ACE2 expression was detected in fetal kidney, rectum and ileum samples from 15 weeks onwards and in the pediatric controls. It was barely detectable in fetal lung samples at 15 + 5 weeks' gestation and not detectable thereafter, and, in the pediatric controls, ACE2 was detectable only in type-2 pneumocytes. No ACE2 expression was found in the cerebral ependymal or parenchymal tissues or in cardiac tissues. ACE2 was expressed in placental syncytiotrophoblast and cytotrophoblast samples, but not in the amnion, from 7 weeks onwards. The intensity and distribution of ACE2 staining in the placenta from the symptomatic SARS-CoV-2 woman was similar to that in the non-infected placentae. CONCLUSIONS: Marked placental expression of ACE2 provides a rationale for vertical transmission at the cellular level. Absence of ACE2 expression in the fetal brain and heart is reassuring regarding the risk of congenital malformation. Clinical follow-up of infected pregnant women and their children is needed to validate these observations. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Differences in cytochrome p450 enzyme expression and activity in fetal and adult tissues.

INTRODUCTION: Human cytochrome p450 (CYP) enzyme expression and activity is lower in the fetus as compared to the adult; however, limited quantitative data exists regarding the specific differences in magnitude or the degree of inducibility due to environmental factors. METHODS: We utilized a combination of in silico- and molecular-based approaches to profile and compare CYP expression/activity in human adult liver and fetal tissues. Using public datasets, we evaluated human CYP expression between: 1) placenta vs. adult livers; 2) fetal vs. adult livers; or 3) five compartments of the human placenta. We generated new experimental data, characterizing expression levels of nine CYPs in placenta/fetal liver vs. adult liver. In a subset of samples, we evaluated CYP3A4 activity. Finally, we summarized evidence of human fetal CYP expression/activity and environmental exposures during pregnancy. RESULTS: In silico, CYPs were predominately expressed at higher levels in the adult liver vs. fetal tissues, with a few noted exceptions. Sixty percent of CYP enzymes were expressed at nominal levels in the placenta. In wet-lab analyses, we observed significant CYP-specific differences in expression/activity between adult and fetal tissues; CYP2E1 and -3A4 were expressed significantly lower in fetal vs. adult livers, while CYP2J2 levels were similar. DISCUSSION: We provide a qualitative review of the expression of the CYP enzyme family in critical sites of xenobiotic distribution during human pregnancy and novel quantitative data regarding fetal CYP expression and activity during mid-gestation. Data outputs may be a resource for modeling predictions of chemical distribution and sensitivity.

A tissue-engineered uterus supports live births in rabbits.

Bioengineered uterine tissue could provide a treatment option for women with uterine factor infertility. In large animal models, reconstruction of the uterus has been demonstrated only with xenogeneic tissue grafts. Here we use biodegradable polymer scaffolds seeded with autologous cells to restore uterine structure and function in rabbits. Rabbits underwent a subtotal uterine excision and were reconstructed with autologous cell-seeded constructs, with nonseeded scaffolds or by suturing. At 6 months postimplantation, only the cell-seeded engineered uteri developed native tissue-like structures, including organized luminal/glandular epithelium, stroma, vascularized mucosa and two-layered myometrium. Only rabbits with cell-seeded constructs had normal pregnancies (four in ten) in the reconstructed segment of the uterus and supported fetal development to term and live birth. With further development, this approach may provide a regenerative medicine solution to uterine factor infertility.

Can aminopeptidase N determined in the meconium be a candidate for biomarker of fetal intrauterine environment?

AIM: To investigate possible association of aminopeptidase N/CD13 with other parameters of possible homeostatic mechanisms in meconium for potential use in identifying intrauterine environmental stress factors during fetal and perinatal life. METHODS: Aminopeptidase N/CD13 (APN/CD13), calprotectin (CAL), myeloperoxidase (MPO), ceruloplasmin (CER), lactoferrin (LF) and interleukin-8 (IL-8) were determined using ELISA kits in 115 meconium samples collected from 30 healthy full term neonates. RESULTS: Significant correlations were established between meconium APN/CD13 [µg/g] (mean ± SD, median, range: 2.88 ± 9.90, 0.94, 0.09-91.54) and MPO (r = 0.77, p = .0000), CER (r = 0.48, p = .0000), LF (r = 0.26, p = .005), IL-8 (r = 0.44, p = .00012) but no correlation of APN/CD13 vs CAL (r = 0.15, p > .05). With increased APN/CD13 concentrations there were increases (p < .05) in concentrations of MPO, CER, LF and L-8. CONCLUSIONS: Meconium APN/CD13 demonstrates characteristic associations with other proteins involved in the regulation of metabolic processes. The panel of APN/CD13, MPO, CER and LF may be candidate biomarker for disorders developing in utero which may have impact on health in later life.

Early pregnancy loss in 15-hydroxyprostaglandin dehydrogenase knockout (15-HPGD-/-) mice due to requirement for embryo 15-HPGD activity.

Prostaglandins (PGs) have critical signaling functions in a variety of processes including the establishment and maintenance of pregnancy, and the initiation of labor. Most PGs are non-enzymatically degraded, however, the two PGs most prominently implicated in the termination of pregnancy, including the initiation of labor, prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α), are enzymatically degraded by 15-hydroxyprostaglandin dehydrogenase (15-HPGD). The role of PG metabolism by 15-HPGD in the maintenance of pregnancy remains largely unknown, as direct functional studies are lacking. To test the hypothesis that 15-PGDH-mediated PG metabolism is essential for pregnancy maintenance and normal labor timing, we generated and analyzed pregnancy in 15-HPGD knockout mice (Hpgd-/-). We report here that pregnancies resulting from matings between 15-HPGD KO mice (Hpgd-/- X Hpgd-/-KO mating) are terminated at mid gestation due to a requirement for embryo derived 15-HPGD. Aside from altered implantation site spacing, pregnancies from KO matings look grossly and histologically normal at days post coitum (dpc) 6.5 and 7.5 of pregnancy. However, virtually all of these pregnancies are resorbed by dpc 8.5. This resorption is preceded by elevation of PGF2∝ but is not preceded by a decrease in circulating progesterone, suggesting that pregnancy loss is a local inflammatory phenomenon rather than a centrally mediated phenomena. This pregnancy loss can be temporarily deferred by indomethacin treatment, but treated pregnancies are not maintained to term and indomethacin treatment increases maternal mortality. We conclude that PG metabolism to inactive products by embryo derived 15-HPGD is essential for pregnancy maintenance in mice, and may serve a similar function during human pregnancy.

Mice exposed to maternal androgen excess and diet-induced obesity have altered phosphorylation of catechol-O-methyltransferase in the placenta and fetal liver.

BACKGROUND/OBJECTIVES: Maternal obesity together with androgen excess in mice negatively affects placental function and maternal and fetal liver function as demonstrated by increased triglyceride content with dysfunctional expression of enzymes and transcription factors involved in de novo lipogenesis and fat storage. To identify changes in molecular pathways that might promote diseases in adulthood, we performed a global proteomic analysis using a liquid-chromatography/mass-spectrometry system to investigate total and phosphorylated proteins in the placenta and fetal liver in a mouse model that combines maternal obesity with maternal androgen excess. METHODS: After ten weeks on a control diet (CD) or high fat/high sugar-diet, dams were mated with males fed the CD. Between gestational day (GD) 16.5 and GD 18.5, mice were injected with vehicle or dihydrotestosterone (DHT) and sacrificed at GD 18.5 prior to dissection of the placentas and fetal livers. Four pools of female placentas and fetal livers were subjected to a global proteomic analysis. Total and phosphorylated proteins were filtered by ANOVA q < 0.05, and this was followed by two-way ANOVA to determine the effect of maternal obesity and/or androgen exposure. RESULTS: In placenta, phosphorylated ATP-citrate synthase was decreased due to maternal obesity, and phosphorylated catechol-O-methyltransferase (COMT) was differentially expressed due to the interaction between maternal diet and DHT exposure. In fetal liver, five total proteins and 48 proteins phosphorylated in one or more sites, were differentially expressed due to maternal obesity or androgen excess. In fetal liver, phosphorylated COMT expression was higher in fetus exposed to maternal obesity. CONCLUSION: These results suggest a common regulatory mechanism of catecholamine metabolism in the placenta and the fetal liver as demonstrated by higher phosphorylated COMT expression in the placenta and fetal liver from animals exposed to diet-induced maternal obesity and lower expression of phosphorylated COMT in animals exposed to maternal androgen excess.

Global loss of leucine carboxyl methyltransferase-1 causes severe defects in fetal liver hematopoiesis.

Leucine carboxyl methyltransferase-1 (LCMT-1) methylates the C-terminal leucine α-carboxyl group of the catalytic subunits of the protein phosphatase 2A (PP2A) subfamily of protein phosphatases, PP2Ac, PP4c, and PP6c. LCMT-1 differentially regulates the formation and function of a subset of the heterotrimeric complexes that PP2A and PP4 form with their regulatory subunits. Global LCMT-1 knockout causes embryonic lethality in mice, but LCMT-1 function in development is unknown. In this study, we analyzed the effects of global LCMT-1 loss on embryonic development. LCMT-1 knockout causes loss of PP2Ac methylation, indicating that LCMT-1 is the sole PP2Ac methyltransferase. PP2A heterotrimers containing the Bα and Bδ B-type subunits are dramatically reduced in whole embryos, and the steady-state levels of PP2Ac and the PP2A structural A subunit are also down ∼30%. Strikingly, global loss of LCMT-1 causes severe defects in fetal hematopoiesis and usually death by embryonic day 16.5. Fetal livers of homozygous lcmt-1 knockout embryos display hypocellularity, elevated apoptosis, and greatly reduced numbers of hematopoietic stem and progenitor cell-enriched Kit+Lin-Sca1+ cells. The percent cycling cells and mitotic indices of WT and lcmt-1 knockout fetal liver cells are similar, suggesting that hypocellularity may be due to a combination of apoptosis and/or defects in specification, self-renewal, or survival of stem cells. Indicative of a possible intrinsic defect in stem cells, noncompetitive and competitive transplantation experiments reveal that lcmt-1 loss causes a severe multilineage hematopoietic repopulating defect. Therefore, this study reveals a novel role for LCMT-1 as a key player in fetal liver hematopoiesis.

Zonation of the drug-metabolizing enzyme cytochrome P450 3A in infant mice begins in pre-weaning period.

The drug-metabolizing enzyme CYP3A is a heterogeneous enzyme found in the liver that displays local characteristics referred to as "zonation." Zonation contributes to improved energy efficiency in metabolism. The objective of this study was to determine a scientific basis for the safety of fetuses and nursing infants in cases in which the use of pharmaceuticals by pregnant and nursing mothers is unavoidable. In addition, we analyzed CYP3A zonation in the liver using mice from the fetus stage to the nursing stage. The livers of mice ranging from day 13.5 of the fetal stage to day 7 of the nursing stage were resected and immunostained using rabbit anti-rat CYP3A2 Ab, which can detect CYP3A11, CYP3A13, CYP3A16, CYP3A25, CYP3A41 and CYP3A44. The results indicated that zonation did not begin in the fetus stage up to day 3 of the nursing stage, and began on day 7 of infancy. This study revealed that changes in the metabolic activity of CYP3A in the liver between the fetal and nursing stages are partly related to zonation. Further studies are needed to establish standards for the proper use of pharmaceuticals by pregnant and nursing mothers.

Polybrominated diphenyl ethers (PBDEs) and hydroxylated PBDE metabolites (OH-PBDEs) in maternal and fetal tissues, and associations with fetal cytochrome P450 gene expression.

BACKGROUND: Human fetal exposures to polybrominated diphenyl ethers (PBDEs) and their metabolites (OH-PBDEs) are unique from adults, and in combination with a different metabolic profile, may make fetal development more sensitive to adverse health outcomes from these exposures. However, we lack data to characterize human fetal PBDE exposures and the metabolic factors that can influence these exposures. OBJECTIVE: We examined differences between 2nd trimester maternal and fetal exposures to PBDEs and OH-PBDEs. We also characterized fetal cytochrome P450 (CYP) mRNA expression and its associations with PBDE exposures. METHODS: We collected paired samples of maternal serum and fetal liver (n=86) with a subset having matched placenta (n=50). We measured PBDEs, OH-PBDEs, and mRNA expression of CYP genes (e.g. CYP1A1, -2E1, -2J2, -2C9) in all samples. As a sensitivity analysis, we measured PBDEs and OH-PBDEs in umbilical cord serum from a subset (n=22). RESULTS: BDE-47 was detected in ≥96% of all tissues. Unadjusted ∑PBDEs concentrations were highest in fetal liver (geometric mean (GM)=0.72ng/g), whereas lipid-adjusted concentrations were highest in cord serum (111.12ng/g lipid). In both cases, fetal concentrations were approximately two times higher than maternal serum levels (GM=0.33ng/g or 48.75ng/g lipid). ΣOH-PBDEs were highest in maternal and cord sera and 20-200 times lower than PBDE concentrations. In regression models, maternal BDE-47 explained more of the model variance of liver than of placenta BDE-47 concentrations (adjusted R2=0.79 vs 0.48, respectively). In adjusted logistic regression models, ∑PBDEs were positively associated with expression of CYP2E1 and -2J2 (placenta), and -1A1 (liver) (p<0.05). CONCLUSION: Our findings suggest that under normal conditions of mid-gestation, the human fetus is directly exposed to concentrations of PBDEs that may be higher than previously estimated based on maternal serum and that these exposures are associated with the expression of mRNAs coding for CYP enzymes. These results will help frame and interpret findings from studies that use maternal or cord blood as proxy measures of fetal exposures, and will inform the molecular pathways by which PBDEs affect human health.

Development of digastric muscles in human foetuses: a review and findings in the flexor digitorum superficialis muscle.

The digastricus and omohyoideus muscles are digastric muscles with two muscle bellies. An insertion tendon of the posterior belly becomes an intermediate tendon in digastricus muscles, whereas a single band-like muscle in omohyoideus muscles may later be interrupted by an intermediate tendon, possibly due to muscle cell death caused by mechanical stress. In human foetuses, an intermediate tendon provides the temporal origins of the tensor veli palatini and tensor tympani muscles. Some reptiles, including snakes, carry multiple series of digastric-like axial muscles, in which each intersegmental septum is likely to become an intermediate tendon. These findings indicate that many pathways are involved in the development of digastric muscles. A review of these morphologies suggested that the flexor digi-torum superficialis (FDS) muscle was a digastric muscle, although the intermediate tendon may not be visible in the surface view in adults. The present observations support the hypothesis that the proximal anlage at the elbow develops into a deep muscle slip to a limited finger, while the distal anlage at the wrist develops into the other slips. The findings suggest that, in the FDS muscle, the proximal and distal bellies of the embryonic digastric muscle fuse together to form a laminar structure, in which muscle slips accumulate from the palmar to the deep side of the forearm. (Folia Morphol 2018; 77, 2: 362-370).

Human fetal dendritic cells promote prenatal T-cell immune suppression through arginase-2.

During gestation the developing human fetus is exposed to a diverse range of potentially immune-stimulatory molecules including semi-allogeneic antigens from maternal cells, substances from ingested amniotic fluid, food antigens, and microbes. Yet the capacity of the fetal immune system, including antigen-presenting cells, to detect and respond to such stimuli remains unclear. In particular, dendritic cells, which are crucial for effective immunity and tolerance, remain poorly characterized in the developing fetus. Here we show that subsets of antigen-presenting cells can be identified in fetal tissues and are related to adult populations of antigen-presenting cells. Similar to adult dendritic cells, fetal dendritic cells migrate to lymph nodes and respond to toll-like receptor ligation; however, they differ markedly in their response to allogeneic antigens, strongly promoting regulatory T-cell induction and inhibiting T-cell tumour-necrosis factor-α production through arginase-2 activity. Our results reveal a previously unappreciated role of dendritic cells within the developing fetus and indicate that they mediate homeostatic immune-suppressive responses during gestation.

Prenatal Diagnosis of Lysosomal Storage Disorders Using Chorionic Villi.

Prenatal enzymatic diagnosis for an array of lysosomal storage disorders (LSDs) can be performed accurately, provided that a confirmed diagnosis by biochemical/molecular study in the index case is available and a strict defined protocol, specific to each individual disorder is followed. The present chapter describes the protocols for reliable and accurate prenatal enzymatic diagnoses by fluorometric and spectrophotometric methods of lysosomal storage disorders: Gaucher, Fabry, Pompe, Niemann Pick A/B, Tay Sach, Sandhoff, GM1, Mucoplysaccharidoses, Wolman, Krabbe, Metachromatic leukodystrophy, and Batten diseases using uncultured chorionic villi samples. The biological reference intervals for enzyme levels in normal and affected fetuses are given for interpretation of prenatal results. It is imperative to establish normal reference interval in each laboratory to take into account the local environment, technical variations, and different ethnicities. Besides, enzyme activity in the fetus should be represented as percentage of the mean activity of enzyme of normal fetuses. The pitfalls and challenges in prenatal diagnosis as well as technical problems in performing enzyme assays are also discussed to help the reader in standardization and performing the assays for correct diagnosis.

Expression of steroidogenic enzymes and steroid receptors in foetal gonads of domestic cat-Sex similarities and differences.

Foetal gonads already produce steroid hormones and by this influence the further development of external and internal genitalia as well as of the brain. Beside this, foetal gonads themselves can be influenced by foetal or maternal hormones. The time course of foetal gonadal development can differ between species. As knowledge on processes in domestic cats is very limited, the steroidogenic enzyme expressions as well as these of steroid receptors were analysed in foetal gonads of domestic cats. We investigated a period from beginning of the second half of pregnancy to the beginning of the third trimester; a phase, where also gonadal development proceeds. The mRNA expression of most of the steroidogenic enzymes was remarkably higher in male gonads compared to female ones on all analysed days. The enzyme mRNA expression in female gonads shows a tendency for an increase towards the beginning of the third trimester, except that of aromatase gene CYP19A1-it shows the opposite trend. CYP19A1 was detectable just in female gonads, indicating that only female foetal gonads are capable of producing oestrogens. Gene expressions of genomically and non-genomically acting steroid receptors for progesterone, androgen and oestrogen reception were observed in gonads of both genders. Slightly higher expressions of some receptors were detected in female compared to male gonads; only for the non-genomically oestrogen receptor GPER, we observed the opposite. The protein staining for progesterone receptor membrane component 1 (PGRMC1) exposed a potential function of it on steroid-producing cell and/or cells that suppose early oogenesis.

[Age-related changes in the content of serine-arginine protein kinase 1 (SRPK1) in human dermis.]

The aim of our work was to examine content of serine-arginine protein kinase 1 (SRPK1) in human dermis at different ages (from 20 weeks of pregnancy to 85 years old). SRPK1, proliferating cells nuclear antigen (PCNA ), endothelial marker CD31 were detected in sections of the skin by indirect immunohistochemistry. Results showed, that content of SRPK1 in dermal fibroblasts was increased form antenatal period to 20 years of life followed by a decrease until 61-85 years period. SRPK1 content in dermal blood vessels is slowly gradually increased from antenatal period to 61-85 age interval. The number of fibroblasts and their proliferative activity, the number of CD31 positive blood vessels in dermis were decreased from antenatal period to 61-85 years period of life. Age-dependent decrease in SRPK1 in dermal fibroblasts from 20 years is associated with a reduction in the number and proliferative activity of fibroblasts. Age-related increase in SRPK1 content in dermal blood vessels is associated with a diminishing of the number of blood vessels. Hence, it can be supposed that SRPK1 has different actions on proliferation of differ components of dermis during aging.

Genetic Expression Profile of Vitamin D Metabolizing Enzymes in the First Trimester.

The aim of this study was to map the genetic expression of the vitamin D metabolizing enzymes CYP27A, CYP27B1, CYP2R1, and CYP24A1 in the first trimester in different human fetal tissues. In addition, the gene expression was correlated with fetal age, season, and presence of single nucleotide polymorphisms (SNPs) in the genes encoding CYP27A1 (rs4674344), CYP2R1 (rs2060793), and CYP24A1 (rs6013897). Fetal samples from livers (n=60), kidneys (n=43), lungs (n=37), and intestines (n=14) were analyzed by quantitative PCR. In addition, the expression of the enzymes was also analyzed in adult livers (n=20). The highest expression of CYP2R1 and CYP24A1 was found in fetal kidney and lung. CYP27A1 was expressed at the highest levels in the liver and kidney and CYP27B1 had the highest levels in the kidney. The expression of fetal hepatic CYP2R1 and CYP27A1 was increased during summertime. Carriers of the G-allele of the rs2060793 SNP in the CYP2R1 gene, a genotype previously associated with rickets, had lower levels of CYP2R1 mRNA.In conclusion, this study suggest that the kidneys rather than the liver, may be of importance for fetal vitamin D metabolism, even for the 25-hydroxylation, during the first trimester. The results also suggest that the lungs and intestines are important for vitamin D metabolism in the fetus. Finally, GG- carriers of the rs2060793 SNP had significantly lower CYP2R1 expression and might be at risk for 25-hydroxyvitamin D deficiency.

Tissue specific expression of human fatty acid oxidation enzyme genes in late pregnancy.

BACKGROUND: Abnormal fatty acid oxidation (FAO) is associated with maternal and fetal complications during pregnancy. The contribution of maternal and fetal tissues to FAO capacity during late pregnancy is important to understand the pathophysiology of pregnancy-associated complications. The aim of this study was to determine the expression levels of mitochondrial FAO enzymes in maternal and fetal tissues during late normal pregnancy. METHODS: We have measured by Real-time PCR the levels of long- and medium -chain acyl-CoA dehydrogenase (LCHAD and MCAD), two acyl-CoA dehydrogenases that catalyze the initial step in the mitochondrial FAO spiral. RESULTS: LCHAD and MCAD were expressed in maternal skeletal muscle, subcutaneous adipose tissue, placenta, and maternal and fetal blood cells. LCHAD gene expression was four- to 16-fold higher than MCAD gene expression in placenta, adipose tissue and skeletal muscle. In contrast, MCAD gene expression was ~5-fold higher in fetal blood than maternal blood (p = 0.02), whereas LCHAD gene expression was similar between fetal blood and maternal blood (p =0.91). CONCLUSIONS: LCHAD and MCAD are differentially expressed in maternal and fetal tissues during normal late pregnancy, which may represent a metabolic adaptation in response to physiological maternal dyslipidemia during late pregnancy.

Constitutive expression of cytochrome P450 in foetal and adult porcine livers-Effects of body weight.

The liver hosts a great number of enzymatically driven processes, including detoxification. The super-family of enzymes named cytochrome P450 (CYP) is the major participant in that process. The expression of CYPs is affected by several factors including life-stage (foetal vs. adult). In the present study we investigated the impact of birth-weight (high or low birth weight) and life-stage on constitutive expression of porcine hepatic CYP1A1, CYP1A2, CYP2A19, CYP2B22, CYP2C33, CYP2D25, CYP2E1 and CYP3A29, as well as the transcription factors controlling their expression; aryl hydrocarbon receptor, constitutive androstane receptor, pregnane X receptor, C/EBP and hepatocyte nuclear factors 1 and 4. Both RT-PCR and western blotting showed a marked increase in the expression of the adult pigs compared with prenatal pigs. Moreover, CYP2E1 mRNA expression was 7.5 fold higher in foetuses with low birth weight compared with foetuses with high birth weight. Gender did not affect the mRNA expression within the different life-stages. These results indicate a similarity to what is observed in humans and porcine foetuses may therefore be a model for humans when studying expression of CYPs.

Distinct expression patterns for type II topoisomerases IIA and IIB in the early foetal human telencephalon.

TOP2A and TOP2B are type II topoisomerase enzymes that have important but distinct roles in DNA replication and RNA transcription. Recently, TOP2B has been implicated in the transcription of long genes in particular that play crucial roles in neural development and are susceptible to mutations contributing to neurodevelopmental conditions such as autism and schizophrenia. This study maps their expression in the early foetal human telencephalon between 9 and 12 post-conceptional weeks. TOP2A immunoreactivity was restricted to cell nuclei of the proliferative layers of the cortex and ganglionic eminences (GE), including the ventricular zone and subventricular zone (SVZ) closely matching expression of the proliferation marker KI67. Comparison with sections immunolabelled for NKX2.1, a medial GE (MGE) marker, and PAX6, a cortical progenitor cell and lateral GE (LGE) marker, revealed that TOP2A-expressing cells were more abundant in MGE than the LGE. In the cortex, TOP2B is expressed in cell nuclei in both proliferative (SVZ) and post-mitotic compartments (intermediate zone and cortical plate) as revealed by comparison with immunostaining for PAX6 and the post-mitotic neuron marker TBR1. However, co-expression with KI67 was rare. In the GE, TOP2B was also expressed by proliferative and post-mitotic compartments. In situ hybridisation studies confirmed these patterns of expression, except that TOP2A mRNA is restricted to cells in the G2/M phase of division. Thus, during early development, TOP2A is likely to have a role in cell proliferation, whereas TOP2B is expressed in post-mitotic cells and may be important in controlling expression of long genes even at this early stage.