Epigenetic Alterations Associated With Early Prenatal Dexamethasone Treatment

LOX overexpression programming mediates the osteoclast mechanism of low peak bone mass in female offspring rats caused by pregnant dexamethasone exposure

BACKGROUND

Osteoporosis is a degenerative disease characterized by reduced bone mass, with low peak bone mass being the predominant manifestation during development and having an intrauterine origin. Pregnant women at risk of preterm delivery are commonly treated with dexamethasone to promote fetal lung development. However, pregnant dexamethasone exposure (PDE) can lead to reduced peak bone mass and susceptibility to osteoporosis in offspring. In this study, we aimed to investigate the mechanism of PDE-induced low peak bone mass in female offspring from the perspective of altered osteoclast developmental programming.

METHODS

0.2 mg/kg.d dexamethasone was injected subcutaneously into rats on gestation days (GDs) 9-20. Some pregnant rats were killed at GD20 to remove fetal rat long bones, the rest were delivered naturally, and some adult offspring rats were given ice water swimming stimulation for two weeks.

RESULTS

The results showed that the fetal rat osteoclast development was inhibited in the PDE group compared with the control group. In contrast, the adult rat osteoclast function was hyperactivation with reduced peak bone mass. We further found that the promoter region methylation levels of lysyl oxidase (LOX) were decreased, the expression was increased, and the production of reactive oxygen species (ROS) was raised in PDE offspring rat long bone before and after birth. Combined in vivo and in vitro experiments, we confirmed that intrauterine dexamethasone promoted the expression and binding of the glucocorticoid receptor (GR) and estrogen receptor β (ERβ) in osteoclasts and mediated the decrease of LOX methylation level and increase of expression through upregulation of 10-11 translocator protein 3 (Tet3).

CONCLUSIONS

Taken together, we confirm that dexamethasone causes osteoclast LOX hypomethylation and high expression through the GR/ERβ/Tet3 pathway, leading to elevated ROS production and that this intrauterine epigenetic programming effect can be carried over to postnatal mediating hyperactivation in osteoclast and reduced peak bone mass in adult offspring. This study provides an experimental basis for elucidating the mechanism of osteoclast-mediated intrauterine programming of low peak bone mass in female offspring of PDE and for exploring its early targets for prevention and treatment. Video Abstract.

Congenital adrenal hyperplasia

Congenital adrenal hyperplasia is a group of autosomal recessive disorders leading to multiple complex hormonal imbalances caused by various enzyme deficiencies in the adrenal steroidogenic pathway. The most common type of congenital adrenal hyperplasia is due to steroid 21-hydroxylase (21-OHase, henceforth 21OH) deficiency. The rare, classic (severe) form caused by 21OH deficiency is characterised by life-threatening adrenal crises and is the most common cause of atypical genitalia in neonates with 46,XX karyotype. After the introduction of life-saving hormone replacement therapy in the 1950s and neonatal screening programmes in many countries, nowadays neonatal survival rates in patients with congenital adrenal hyperplasia are high. However, disease-related mortality is increased and therapeutic management remains challenging, with multiple long-term complications related to treatment and disease affecting growth and development, metabolic and cardiovascular health, and fertility. Non-classic (mild) forms of congenital adrenal hyperplasia caused by 21OH deficiency are more common than the classic ones; they are detected clinically and primarily identified in female patients with hirsutism or impaired fertility. Novel treatment approaches are emerging with the aim of mimicking physiological circadian cortisol rhythm or to reduce adrenal hyperandrogenism independent of the suppressive effect of glucocorticoids.

First Trimester Dexamethasone Treatment Is Not Associated With Alteration in Resting-state Connectivity at Adolescent or Adult Age

CONTEXT

Prenatal treatment with dexamethasone (DEX) has been used to prevent virilization in females at risk of congenital adrenal hyperplasia (CAH). Both affected and unaffected girls, as well boys, are treated until the genotype and sex of the fetus is known (gestational weeks 10-12). After that, only affected girls are treated until term. Exposure to a high synthetic glucocorticoid dosage may alter the developmental trajectory of the brain, with alterations in resting-state functional connectivity of the brain at adult age.

OBJECTIVE

To investigate resting-state functional connectivity in subjects at risk of having CAH, exposed to DEX treatment during the first trimester of fetal life, both in the whole brain and in 3 regions of interest (amygdala, hippocampus, and superior frontal gyrus).

DESIGN, SETTING, AND PARTICIPANTS

Eighteen participants (8 females) at risk of having CAH, exposed to DEX treatment, and 38 controls (24 females), age range 16 to 26 years, from a single research institute, underwent functional magnetic resonance imaging of the brain during rest. We used 2 different approaches: an exploratory whole-brain analysis and seed-based analysis. For seed-based analysis, we chose 3 different brain regions (amygdala, hippocampus, and superior frontal gyrus) based on our previous findings and literature evidence.

RESULTS

We did not observe any differences in functional connectivity during rest, either in the whole brain nor in seed-based connectivity analyses at this adolescent and young adult age.

CONCLUSIONS

Our results are reassuring; however, future studies on larger samples and with more sensitive methodologies are needed to confirm these findings.

Long-Term Outcomes of Congenital Adrenal Hyperplasia

A plethora of negative long-term outcomes have been associated with congenital adrenal hyperplasia (CAH). The causes are multiple and involve supra-physiological gluco- and mineralocorticoid replacement, excess adrenal androgens both intrauterine and postnatal, elevated steroid precursor and adrenocorticotropic hormone levels, living with a congenital condition as well as the proximity of the cytochrome P450 family 21 subfamily A member 2 (CYP21A2) gene to other genes. This review aims to discuss the different long-term outcomes of CAH.

Altered hippocampal GR/KCC2 signaling mediates susceptibility to convulsion in male offspring following dexamethasone exposure during pregnancy in rats

Epidemiological research suggests that convulsions may have an intrauterine developmental origin related to the application of dexamethasone, an artificially synthesized glucocorticoid. Here, using a rat animal model of prenatal dexamethasone exposure (PDE) we confirm that PDE can cause susceptibility to convulsions in male offspring and explore the epigenetic programming mechanism underlying this effect related to intrauterine type 2K⁺-Cl^- cotransporter (KCC2). Wistar rats were injected with dexamethasone (0.2mg/kg/d) subcutaneously during the gestational days (GD) 9-20 and part of the offspring was given lithium pilocarpine (LiPC) at postnatal week 10. Our results showed that male offspring of the PDE+LiPC group exhibited convulsions susceptibility, as well as increased hippocampal gamma-aminobutyric acid (GABA) and intracellular chloride ions level and decreased GABA receptor expression. The offspring also showed a decrease of hippocampal KCC2 H3K14ac levels and KCC2 expression. PDE male fetal rats (GD20) showed similar changes to male offspring after birth and exhibited an increased expression of glucocorticoid receptor (GR) and histone deacetylase type 2 (HDAC2). We observed effects consistent with those observed in PDE fetal rats following in vitro dexamethasone treatment of the fetal rat hippocampal neuron H19-7 cell line, and the effects could be reversed by treatment with a GR inhibitor (RU486) or HDAC2 inhibitor (romidepsin). Taken together, this study confirmed that PDE causes a reduction of H3K14ac levels in the KCC2 promoter region caused by activation of fetal hippocampal GR-HDAC2-KCC2 signaling. We proposed that this abnormal epigenetic modification is the mechanism underlying offspring convulsions susceptibility. CATEGORIES: mechanism of toxicity.

Ambulatory Blood Pressure Monitoring in Children and Adults Prenatally Exposed to Dexamethasone Treatment

CONTEXT

The clinical use of dexamethasone (DEX) prenatally to reduce virilization of external genitalia in female fetuses with congenital adrenal hyperplasia (CAH) is efficient but still controversial. It remains challenging to prevent the excessive exposure of DEX in unborn healthy babies during the first trimester of pregnancy.

OBJECTIVE

Since endogenous glucocorticoids contribute to the maintenance of blood pressure (BP) and since events during fetal life may program the fetus and affect future metabolic health, the aim of this study was to analyze ambulatory BP measurements in CAH-unaffected children and adults that were prenatally exposed to DEX treatment.

METHODS

Ambulatory BP measurements were analyzed in 33 (16 female) DEX-treated participants aged 5.1 to 26.3 years (19 participants aged ≤ 18 years) and in 54 (28 female) age- and sex-matched apparently healthy controls aged 5.5 to 25.3 years (27 participants aged ≤ 18 years) with ambulatory normotension.

RESULTS

Participants' age, height, weight, and body mass index were similar between the DEX-treated group and the control group. Heart rate, 24-hour BP, pulse pressure, and nighttime dipping did not statistically significantly differ between DEX-treated participants and controls.

CONCLUSION

Our study suggests that prenatal DEX treatment in CAH-unaffected children and adults does not appear to adversely affect ambulatory BP later in life. Our observations need to be confirmed in larger studies.

DNA methylation in former extremely low birth weight newborns: association with cardiovascular and endocrine function

BACKGROUND

There is increased risk of cardiovascular, metabolic, and hypertensive disorders in later life in the preterm population. We studied school-age children who had been born extremely premature who had undergone endocrine, cardiovascular, and anthropometric evaluations.

METHODS

School age measurements of salivary cortisol, adrenal androgens, blood pressure, and anthropometric markers were correlated with DNA methylation of 11-betahydroxysteroid dehydrogenase type 2 (11BHSD2), leptin, and the LINE1 repetitive DNA element.

RESULTS

We observed a modest correlation between log AUC for salivary cortisol and methylation of leptin in preterm infants and a negative correlation between methylation of region 1 of the glucocorticoid receptor (GR in term-born infants. There was an association between LINE1 methylation and cortisol response to awakening and a negative correlation between LINE1 and systolic blood pressure at 6-7 years. Methylation of the GR promoter region showed a positive association with systolic blood pressure at 6-7 years of age.

CONCLUSIONS

These results show that extremely preterm birth, followed by complex patterns of endocrine, cardiovascular, and metabolic exposures during early postnatal life, is associated with lasting changes in DNA methylation patterns in genes involved in hypothalamic pituitary adrenal axis function, adrenal hormonal regulation, and cardiometabolic risk.

IMPACT

Preterm infants have significant environmental and physiological exposures during early life that may have lasting impact on later function. Alterations in hypothalamic pituitary adrenal axis (HPA) function have been associated with these exposures. We examined the associated changes in DNA methylation of important genes involved in HPA function, metabolism, and global DNA methylation. The changes we saw in DNA methylation may help to explain associated cardiovascular, metabolic, and growth disturbance in these children in later life.

Prenatal dexamethasone treatment for classic 21-hydroxylase deficiency in Europe

OBJECTIVE

To assess the current medical practice in Europe regarding prenatal dexamethasone (Pdex) treatment of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency.

DESIGN AND METHODS

A questionnaire was designed and distributed, including 17 questions collecting quantitative and qualitative data. Thirty-six medical centres from 14 European countries responded and 30 out of 36 centres were reference centres of the European Reference Network on Rare Endocrine Conditions, EndoERN.

RESULTS

Pdex treatment is currently provided by 36% of the surveyed centres. The treatment is initiated by different specialties, that is paediatricians, endocrinologists, gynaecologists or geneticists. Regarding the starting point of Pdex, 23% stated to initiate therapy at 4-5 weeks postconception (wpc), 31% at 6 wpc and 46 % as early as pregnancy is confirmed and before 7 wpc at the latest. A dose of 20 µg/kg/day is used. Dose distribution among the centres varies from once to thrice daily. Prenatal diagnostics for treated cases are conducted in 72% of the responding centres. Cases treated per country and year vary between 0.5 and 8.25. Registries for long-term follow-up are only available at 46% of the centres that are using Pdex treatment. National registries are only available in Sweden and France.

CONCLUSIONS

This study reveals a high international variability and discrepancy in the use of Pdex treatment across Europe. It highlights the importance of a European cooperation initiative for a joint international prospective trial to establish evidence-based guidelines on prenatal diagnostics, treatment and follow-up of pregnancies at risk for CAH.

No long-term effects of antenatal synthetic glucocorticoid exposure on epigenetic regulation of stress-related genes

Antenatal synthetic glucocorticoid (sGC) treatment is a potent modifier of the hypothalamic-pituitary-adrenal (HPA) axis. In this context, epigenetic modifications are discussed as potential regulators explaining how prenatal exposure to GCs might translate into persistent changes of HPA axis "functioning". The purpose of this study was to investigate whether DNA methylation and gene expression profiles of stress-associated genes (NR3C1; FKBP5; SLC6A4) may mediate the persistent effects of sGC on cortisol stress reactivity that have been previously observed. In addition, hair cortisol concentrations (hairC) were investigated as a valid biomarker of long-term HPA axis activity. This cross-sectional study comprised 108 term-born children and adolescents, including individuals with antenatal GC treatment and controls. From whole blood, DNA methylation was analyzed by targeted deep bisulfite sequencing. Relative mRNA expression was determined by RT-qPCR experiments and qBase analysis. Acute stress reactivity was assessed by the Trier Social Stress Test (TSST) measuring salivary cortisol by ELISA and hairC concentrations were determined from hair samples by liquid chromatography coupled with tandem mass spectrometry. First, no differences in DNA methylation and mRNA expression levels of the stress-associated genes between individuals treated with antenatal sGC compared to controls were found. Second, DNA methylation and mRNA expression levels were neither associated with cortisol stress reactivity nor with hairC. These findings do not corroborate the belief that DNA methylation and mRNA expression profiles of stress-associated genes (NR3C1; FKBP5; SLC6A4) play a key mediating role of the persistent effects of sGC on HPA axis functioning.

Congenital Adrenal Hyperplasia-Current Insights in Pathophysiology, Diagnostics, and Management

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders affecting cortisol biosynthesis. Reduced activity of an enzyme required for cortisol production leads to chronic overstimulation of the adrenal cortex and accumulation of precursors proximal to the blocked enzymatic step. The most common form of CAH is caused by steroid 21-hydroxylase deficiency due to mutations in CYP21A2. Since the last publication summarizing CAH in Endocrine Reviews in 2000, there have been numerous new developments. These include more detailed understanding of steroidogenic pathways, refinements in neonatal screening, improved diagnostic measurements utilizing chromatography and mass spectrometry coupled with steroid profiling, and improved genotyping methods. Clinical trials of alternative medications and modes of delivery have been recently completed or are under way. Genetic and cell-based treatments are being explored. A large body of data concerning long-term outcomes in patients affected by CAH, including psychosexual well-being, has been enhanced by the establishment of disease registries. This review provides the reader with current insights in CAH with special attention to these new developments.

Epigenetic regulation of pediatric and neonatal immune responses

Epigenetic regulation of transcription is a collective term that refers to mechanisms known to regulate gene transcription without changing the underlying DNA sequence. These mechanisms include DNA methylation and histone tail modifications which influence chromatin accessibility, and microRNAs that act through post-transcriptional gene silencing. Epigenetics is known to regulate a variety of biological processes, and the role of epigtenetics in immunity and immune-mediated diseases is becoming increasingly recognized. While DNA methylation is the most widely studied, each of these systems play an important role in the development and maintenance of appropriate immune responses. There is clear evidence that epigenetic mechanisms contribute to developmental stage-specific immune responses in a cell-specific manner. There is also mounting evidence that prenatal exposures alter epigenetic profiles and subsequent immune function in exposed offspring. Early life exposures that are associated with poor long-term health outcomes also appear to impact immune specific epigenetic patterning. Finally, each of these epigenetic mechanisms contribute to the pathogenesis of a wide variety of diseases that manifest during childhood. This review will discuss each of these areas in detail. IMPACT: Epigenetics, including DNA methylation, histone tail modifications, and microRNA expression, dictate immune cell phenotypes. Epigenetics influence immune development and subsequent immune health. Prenatal, perinatal, and postnatal exposures alter immune cell epigenetic profiles and subsequent immune function. Numerous pediatric-onset diseases have an epigenetic component. Several successful strategies for childhood diseases target epigenetic mechanisms.

Epigenetic alterations associated with dexamethasone sodium phosphate through DNMT and TET in RPE cells

PURPOSE

To elucidate the mechanism behind epigenetic alteration associated with dexamethasone (DEX) sodium phosphate treatment.

METHODS

We performed enzyme-linked immunosorbent assay to quantify changes in global DNA methylation and hydroxymethylation, quantitative real-time PCR (qRT-PCR) of the DNA methylation- and hydroxymethylation-related gene, in vitro DNA methyltransferase (DNMT) enzymatic activity assays with purified DNMTs, and DNA hydroxymethylation pattern with super-resolution imaging.

RESULTS

We identified global DNA hypomethylation and hyper-hydroxymethylation upon DEX treatment, associated with aberrant mRNA expression levels of DNMT and ten-eleven translocation (TET) proteins. Additionally, DEX exposure could directly hinder DNMT activities.

CONCLUSIONS

We showed that DEX-induced epigenetic alterations are linked to aberrant DNMT and TET expression, potentially through an essential role of DNMT.

Clinical outcomes in 21-hydroxylase deficiency

PURPOSE OF REVIEW

The introduction of synthetic glucocorticoids 70 years ago made survival possible in classic 21-hydroxylase deficiency (21OHD). The currently used glucocorticoid therapy may lead to unphysiological dosing with negative consequencies on health in addition to the problems that may arise due to androgen over-exposure.

RECENT FINDINGS

Fertility in females with 21OHD seemed to be impaired, especially in the salt-wasting (SW) phenotype but when pregnancies did occur there was a higher risk for gestational diabetes and cesearean section. Increased fat mass, body mass index, insulin resistance and frequency of autoimmune disorders as well as impaired echocardiographic parameters and lower bone mineral density were found in 21OHD compared to controls. Negative effects on cognitive functions have been identified. Adrenal tumors, especially myelolipomas, were prevalent. Increased knowledge on steroid metabolism in 21OHD and urine steroid profiling may improve assessment of treatment efficacy. Nevanimibe, abiraterone acetate and anastrozole may have a place in the future management of 21OHD. Long-acting glucocorticoids may be a less favorable, especially dexamethasone.

SUMMARY

The various clinical outcomes need regular monitoring. Negative consequencies are to large extent the result of the unphysiological glucocorticoid replacement. Modern management with improved follow-up and future addition of new drugs may improve outcomes.

Programming changes of hippocampal miR-134-5p/SOX2 signal mediate the susceptibility to depression in prenatal dexamethasone-exposed female offspring

Depression is a neuropsychiatric disorder and has intrauterine developmental origins. This study aimed to confirm the depression susceptibility in offspring rats induced by prenatal dexamethasone exposure (PDE) and to further explore the intrauterine programming mechanism. Wistar rats were injected with dexamethasone (0.2 mg/kg·d) subcutaneously during the gestational days 9-20 and part of the offspring was given chronic stress at postnatal weeks 10-12. Behavioral results showed that the adult PDE female offspring was susceptible to depression, accompanied by increased hippocampal miR-134-5p expression and decreased sex-determining region Y-box 2 (SOX2) expression, as well as disorders of neural progenitor cells proliferation and hippocampal neurogenesis. The PDE female fetal rats presented consistent changes with the adult offspring, accompanied by the upregulation of glucocorticoid receptor (GR) expression and decreased sirtuin 1 (SIRT1) expression. We further found that the H3K9ac level of the miR-134-5p promoter was significantly increased in the PDE fetal hippocampus, as well as in adult offspring before and after chronic stress. In vitro, the changes of GR/SIRT1/miR-134-5p/SOX2 signal by dexamethasone were consistent with in vivo experiments, which could be reversed by GR receptor antagonist, SIRT1 agonist, and miR-134-5p inhibitor. This study confirmed that PDE led to an increased expression level as well as H3K9ac level of miR-134-5p by activating the GR/SIRT1 pathway in the fetal hippocampus and then inhibited the SOX2 expression. The programming effect mediated by the abnormal epigenetic modification could last from intrauterine to adulthood, which constitutes the intrauterine programming mechanism leading to hippocampal neurogenesis disorders and depression susceptibility in female offspring. Intrauterine programming mechanism for the increased depressive susceptibility in adult female offspring by prenatal dexamethasone exposure (PDE). GR, glucocorticoid receptor; SIRT1, sirtuin 1; SOX2, sex-determining region Y-box 2; NPCs, neuroprogenitor cells; H3K9ac, histone 3 lysine 9 acetylation; GRE, glucocorticoid response element.

First Trimester DEX Treatment Is Not Associated with Altered Brain Activity During Working Memory Performance in Adults

CONTEXT

Prenatal dexamethasone (DEX) treatment is sometimes used in pregnancies at risk for congenital adrenal hyperplasia (CAH) to prevent virilization in female fetuses with CAH. In boys and in fetuses not having CAH, there is no benefit of early DEX treatment and the risks of this therapy must be thoroughly investigated. High doses of prenatal glucocorticoid might alter the developmental trajectory of the brain into adulthood, even for CAH unaffected subjects treated with DEX for a short term during the first trimester.

OBJECTIVE

The present study investigated brain activation during working memory performance in DEX-treated subjects compared with controls.

DESIGN, SETTING, AND PARTICIPANTS

We tested 18 participants who were exposed to DEX during the first trimester of fetal life but did not have CAH (8 females; mean age 20.78 [standard deviation (SD), 2.67] years) and 40 control participants (24 females; mean age 20.53 [SD, 2.64]) from a single research institute. Participants underwent functional magnetic resonance imaging on a 3T scanner during a verbal and visuospatial working memory task.

RESULTS

We did not observe any differences in brain activity during working memory performance. However, DEX-treated subjects responded faster during the experimental condition of the verbal WM task.

CONCLUSIONS

First trimester DEX treatment did not seem to result in altered working memory-related brain activity at adult age. Our findings contribute to the risk-benefit assessment of prenatal DEX treatment in the context of CAH.

Clinical outcomes and characteristics of P30L mutations in congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Despite numerous studies in the field of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, some clinical variability of the presentation and discrepancies in the genotype/phenotype correlation are still unexplained. Some, but not all, discordant phenotypes caused by mutations with known enzyme activity have been explained by in silico structural changes in the 21-hydroxylase protein. The incidence of P30L mutation varies in different populations and is most frequently found in several Central and Southeast European countries as well as Mexico. Patients carrying P30L mutation present predominantly as non-classical CAH; however, simple virilizing forms are found in up to 50% of patients. Taking into consideration the residual 21-hydroxulase activity present with P30L mutation this is unexpected. Different mechanisms for increased androgenization in patients carrying P30L mutation have been proposed including influence of different residues, accompanying promotor allele variability or mutations, and individual androgene sensitivity. Early diagnosis of patients who would present with SV is important in order to improve outcome. Outcome studies of CAH have confirmed the uniqueness of this mutation such as difficulties in phenotype classification, different fertility, growth, and psychologic issues in comparison with other genotypes. Additional studies of P30L mutation are warranted.

First-Trimester Prenatal Dexamethasone Treatment Is Associated With Alterations in Brain Structure at Adult Age

CONTEXT

Prenatal treatment of human disease is rare. Dexamethasone (DEX) is used in pregnancies at risk for congenital adrenal hyperplasia (CAH) to prevent virilization in an affected female fetus. The safety and long-term consequences of prenatal DEX exposure on the brain are largely unknown.

OBJECTIVE

We investigate whether first-trimester prenatal DEX treatment is associated with alterations in brain structure at adult age, and if these alterations are associated with DNA methylation, mood, and cognitive abilities.

DESIGN, SETTING, AND PARTICIPANTS

T1-weighted and diffusion-weighted imaging scans, from a single research institute, are compared between 19 (9 women) first-trimester DEX-treated individuals, at risk of CAH but not having CAH, and 43 (26 women) controls (age range, 16.0-26.4 years).

RESULTS

DEX-treated participants showed bilateral enlargement of the amygdala, increased surface area and volume of the left superior frontal gyrus, and widespread increased radial, mean, and axial diffusivity of white matter, in particular in the superior longitudinal fasciculi and corticospinal tracts. In the DEX-treated group, increased mean and radial diffusivity correlated with increased methylation of the promotor region of the FKBP5 gene. There were no group differences in cognition or in scales assessing depression or anxiety, and the relationship between brain structure and cognition did not differ between DEX-treated and controls.

CONCLUSIONS

First-trimester prenatal DEX treatment is associated with structural alterations of the brain at adult age, with an accompanying change in gene methylation. The findings add to the safety concerns of prenatal DEX treatment in the context of CAH.

Perturbed Beta-Cell Function and Lipid Profile After Early Prenatal Dexamethasone Exposure in Individuals Without CAH

BACKGROUND

Prenatal treatment with dexamethasone (DEX) reduces virilization in girls with congenital adrenal hyperplasia (CAH). The treatment is effective but may result in long-lasting adverse effects. In this study we explore the effects of DEX on metabolism in individuals not having CAH but treated with DEX during the first trimester of fetal life.

METHOD

All DEX-treated participants (n = 40, age range 5.1-26.4 years) and controls (n = 75, age range 4.5-26.6 years) were assessed with fasting blood samples to measure blood count, renal function, glucose homeostasis, and serum lipid profiles.

RESULTS

There were no significant differences between DEX and control participants for birth parameters, weight and height, or body mass index at the time of testing. Analyzing the entire cohort, we found no significant effects of DEX on blood count, renal function, or serum lipid profiles. However, a lower HOMA-β index in the DEX-treated individuals (U = 893.0; P = 0.049) was observed. Post hoc analyses revealed an effect in girls (U = 152.5; P = 0.024) but not in boys (U = 299.5; P = 0.550). The effect on HOMA-β persisted (U = 117.5; P = 0.048) after analyzing data separately in the participants < 16 years of age. In addition, we observed higher plasma glucose levels (F = 14.6; P = 0.001) in the DEX-treated group. The participants ≥ 16 years of age in the DEX-treated group had significantly higher total plasma cholesterol (F = 9.8; P = 0.003) and higher low-density lipoprotein cholesterol levels (F = 7.4; P = 0,009).

CONCLUSION

Prenatal DEX exposure in early pregnancy has negative effects on beta-cell function and lipid profile in individuals without CAH already at a young age.

Genome-wide investigation of DNA methylation in congenital adrenal hyperplasia

Patients with congenital adrenal hyperplasia (CAH) are at risk of long-term cognitive and metabolic sequelae with some of the effects being attributed to the chronic glucocorticoid treatment that they receive. Our pilot study investigates genome-wide DNA methylation in patients with CAH to determine whether there is preliminary evidence for epigenomic reprogramming as well as any relationship to patient outcome. Here, we analysed CD4 + T cell DNA from 28 patients with CAH (mean age = 18.5 ± 6.5 years [y]) and 37 population controls (mean age = 17.0 ± 6.1 y) with the Infinium-HumanMethylation450 BeadChip array to measure genome-wide locus-specific DNA methylation levels. Effects of CAH, phenotype and CYP21A2 genotype on methylation were investigated as well as the association between differentially methylated CpGs and glucose homeostasis, blood lipid profile, and cognitive functions. In addition, we report data on a small cohort of 11 patients (mean age = 19.1, ±6.0 y) with CAH who were treated prenatally with dexamethasone (DEX) in addition to postnatal glucocorticoid treatment. We identified two CpGs to be associated with patient phenotype: cg18486102 (located in the FAIM2 gene; rho = 0.58, adjusted p = 0.027) and cg02404636 (located in the SFI1 gene; rho = 0.58, adjusted p = 0.038). cg02404636 was also associated with genotype (rho = 0.59, adjusted p = 0.024). Higher levels of serum C-peptide was also observed in patients with CAH (p = 0.044). Additionally, levels of C-peptide and HbA1c were positively correlated with patient phenotype (p = 0.044 and p = 0.034) and genotype (p = 0.044 and p = 0.033), respectively. No significant association was found between FAIM2 methylation and cognitive or metabolic outcome. However, SFI1 TSS methylation was associated with fasting plasma HDL cholesterol levels (p = 0.035). In conclusion, in this pilot study, higher methylation levels in CpG sites covering FAIM2 and SFI1 were associated with disease severity. Hypermethylation in these genes may have implications for long-term cognitive and metabolic outcome in patients with CAH, although the data must be interpreted with caution due to the small sample size. Additional studies in larger cohorts are therefore warranted.

Leveraging biological and statistical covariates improves the detection power in epigenome-wide association testing

BACKGROUND

Epigenome-wide association studies (EWAS), which seek the association between epigenetic marks and an outcome or exposure, involve multiple hypothesis testing. False discovery rate (FDR) control has been widely used for multiple testing correction. However, traditional FDR control methods do not use auxiliary covariates, and they could be less powerful if the covariates could inform the likelihood of the null hypothesis. Recently, many covariate-adaptive FDR control methods have been developed, but application of these methods to EWAS data has not yet been explored. It is not clear whether these methods can significantly improve detection power, and if so, which covariates are more relevant for EWAS data.

RESULTS

In this study, we evaluate the performance of five covariate-adaptive FDR control methods with EWAS-related covariates using simulated as well as real EWAS datasets. We develop an omnibus test to assess the informativeness of the covariates. We find that statistical covariates are generally more informative than biological covariates, and the covariates of methylation mean and variance are almost universally informative. In contrast, the informativeness of biological covariates depends on specific datasets. We show that the independent hypothesis weighting (IHW) and covariate adaptive multiple testing (CAMT) method are overall more powerful, especially for sparse signals, and could improve the detection power by a median of 25% and 68% on real datasets, compared to the ST procedure. We further validate the findings in various biological contexts.

CONCLUSIONS

Covariate-adaptive FDR control methods with informative covariates can significantly increase the detection power for EWAS. For sparse signals, IHW and CAMT are recommended.

Alteration of the brain methylation landscape following postnatal inflammatory injury in rat pups

Preterm infants are vulnerable to inflammation-induced white matter injury (WMI), which is associated with neurocognitive impairment and increased risk of neuropsychiatric diseases in adulthood. Epigenetic mechanisms, particularly DNA methylation, play a role in normal development and modulate the response to pathological challenges. Our aims were to determine how WMI triggered DNA methylation alterations in brains of neonatal rats and if such changes persisted over time. We used a robust model of WMI by injecting lipopolysaccharide (LPS) or sterile saline in the corpus callosum of 3-day-old (P3) rat pups. Brains were collected 24 hours (P4) and 21 days post-injection (P24). We extracted genomic DNA from the brain to establish genome-wide quantitative DNA methylation profiles using reduced representation bisulfite sequencing. Neonatal LPS exposure induced a persistent increased methylation of genes related to nervous system development and a reduced methylation of genes associated with inflammatory pathways. These findings suggest that early-life neuroinflammatory exposure impacts the cerebral methylation landscape with determining widespread epigenetic modifications especially in genes related to neurodevelopment.

46,XX DSD due to Androgen Excess in Monogenic Disorders of Steroidogenesis: Genetic, Biochemical, and Clinical Features

The term 'differences of sex development' (DSD) refers to a group of congenital conditions that are associated with atypical development of chromosomal, gonadal, or anatomical sex. Disorders of steroidogenesis comprise autosomal recessive conditions that affect adrenal and gonadal enzymes and are responsible for some conditions of 46,XX DSD where hyperandrogenism interferes with chromosomal and gonadal sex development. Congenital adrenal hyperplasias (CAHs) are disorders of steroidogenesis that mainly involve the adrenals (21-hydroxylase and 11-hydroxylase deficiencies) and sometimes the gonads (3-beta-hydroxysteroidodehydrogenase and P450-oxidoreductase); in contrast, aromatase deficiency mainly involves the steroidogenetic activity of the gonads. This review describes the main genetic, biochemical, and clinical features that apply to the abovementioned conditions. The activities of the steroidogenetic enzymes are modulated by post-translational modifications and cofactors, particularly electron-donating redox partners. The incidences of the rare forms of CAH vary with ethnicity and geography. The elucidation of the precise roles of these enzymes and cofactors has been significantly facilitated by the identification of the genetic bases of rare disorders of steroidogenesis. Understanding steroidogenesis is important to our comprehension of differences in sexual development and other processes that are related to human reproduction and fertility, particularly those that involve androgen excess as consequence of their impairment.

Increased Risk of Autoimmune Disorders in 21-Hydroxylase Deficiency: A Swedish Population-Based National Cohort Study

CONTEXT

The prevalence of autoimmune disorders in individuals with 21-hydroxylase deficiency (21OHD) is unclear. The gene responsible, CYP21A2, is located in a highly immunologically active region.

OBJECTIVE

To study the prevalence of autoimmune disorders in individuals with 21OHD.

DESIGN SETTING AND PARTICIPANTS

Patients with 21OHD (n = 714) were compared with controls matched for sex, year, and place of birth (n = 71,400). Data were derived by linking National Population-Based Registers. Subgroup analyses were performed regarding phenotype and CYP21A2 genotype.

MAIN OUTCOME MEASURES

Number and type of autoimmune disorders.

RESULTS

Mean age (± SD) was 29.8 ± 18.4 years. Individuals with 21OHD had more autoimmune disorders than did controls [7.4% vs 5.1%, P < 0.01; relative risk (RR) 1.47 (95% CI, 1.13 to 1.91)], especially male patients [6.8% vs 4.1%, P < 0.05; RR, 1.64 (95% CI, 1.08 to 2.49)], whereas it did not reach significance for female patients [7.9% vs 5.8%, P = 0.068; RR, 1.37 (95% CI, 0.98 to 1.92)]. Among the specific autoimmune groups and disorders, autoimmune endocrine disorders and autoimmune thyroid disorders, including Graves disease, were significantly increased in the entire cohort of patients and for male and female patients separately. Inflammatory bowel disease (IBD) and systemic connective tissue disorders did not reach significant levels for the entire cohort (P = 0.075 and 0.05, respectively), but male patients were more affected by IBD (P = 0.022). The groups with milder phenotypes and genotypes seemed to be more affected by autoimmune disorders.

CONCLUSIONS

21OHD was associated with an increased prevalence of autoimmune disorders. The relatively young age of the patient cohort and possible protective effects by glucocorticoid treatment may have underestimated the risk.