Aromatase deficiency in a Chinese adult man caused by novel compound heterozygous CYP19A1 mutations: effects of estrogen replacement therapy on the bone, lipid, liver and glucose metabolism

Updates on Mechanisms of Cytochrome P450 Catalysis of Complex Steroid Oxidations

Cytochrome P450 (P450) enzymes dominate steroid metabolism. In general, the simple C-hydroxylation reactions are mechanistically straightforward and are generally agreed to involve a perferryl oxygen species (formally FeO3+). Several of the steroid transformations are more complex and involve C-C bond scission. We initiated mechanistic studies with several of these (i.e., 11A1, 17A1, 19A1, and 51A1) and have now established that the dominant modes of catalysis for P450s 19A1 and 51A1 involve a ferric peroxide anion (i.e., Fe3+O2¯) instead of a perferryl ion complex (FeO3+), as demonstrated with 18O incorporation studies. P450 17A1 is less clear. The indicated P450 reactions all involve sequential oxidations, and we have explored the processivity of these multi-step reactions. P450 19A1 is distributive, i.e., intermediate products dissociate and reassociate, but P450s 11A1 and 51A1 are highly processive. P450 17A1 shows intermediate processivity, as expected from the release of 17-hydroxysteroids for the biosynthesis of key molecules, and P450 19A1 is very distributive. P450 11B2 catalyzes a processive multi-step oxidation process with the complexity of a chemical closure of an intermediate to a locked lactol form.

Sex Steroids Regulate Liver Fat Content and Body Fat Distribution in Both Men and Women: A Study in Transgender Persons

CONTEXT

Liver fat content and visceral fat volume are associated with insulin resistance and cardiovascular disease and are higher in men than in women.

OBJECTIVE

To determine the effect of estradiol and testosterone treatment on liver fat and visceral fat in transgender persons.

DESIGN

Open-label intervention study (SHAMVA) with a 1-year follow-up.

SETTING

Gender clinic in a hospital.

PATIENTS

8 trans women and 18 trans men receiving hormone treatment.

INTERVENTIONS

Trans women received an antiandrogen and after 6 weeks estradiol was added. Trans men were randomized to receive triptorelin, testosterone, and anastrozole for 12 weeks or triptorelin and testosterone for 12 weeks, followed by only testosterone until week 52.

MAIN OUTCOME MEASURES

Liver fat content, visceral and abdominal subcutaneous fat volume, measured by magnetic resonance spectrometry or imaging at baseline, 6, 8, 18, and 58 weeks in transwomen or at baseline; at 6 and 12 weeks in trans men with anastrozole; and at 52 weeks in trans men without anastrozole.

RESULTS

In trans women, liver fat content decreased by 1.55% (-2.99 to -0.12) after 58 weeks, compared to week 6. Visceral fat did not change. In trans men with anastrozole, the liver fat content and visceral fat volume did not change. In trans men without anastrozole, after 52 weeks, liver fat content increased by 0.83% (0.14 to 1.52) and visceral fat volume increased by 34% (16 to 51).

CONCLUSIONS

Sex hormones regulate liver fat content and visceral fat in men and women.

Aromatase deficiency caused by mutation of CYP19A1 gene: A case report

Aromatase deficiency (AD) is a rare autosomal recessive genetic disease caused by loss-of-function mutations in aromatase gene (CYP19A1), leading to congenital estrogen deficiency syndrome. Both mothers of AD patients during pregnancy and female AD fetus show virilization, while male patients are usually diagnosed in adulthood due to continued height increase and metabolic abnormalities. In 2019, a patient with AD was admitted in the Second Xiangya Hospital. The patient was a 37-year-old adult male who continued to grow linearly after adulthood. His estradiol was below the measurable line, the follicle-stimulating hormone (FSH) increased, bone age delayed, epiphysis unfused, and the bone mass reduced. CYP19A1 gene detection showed that c.1093C>T, p.R365W was homozygous mutation. This disease is rare in clinic. Clinicians need to raise awareness of the disease for early diagnosis and treatment to improve the long-term prognosis of patients.

Association of the CYP19A1 rs700518 Polymorphism with Selected Markers of Bone Metabolism in Women with Hyperandrogenism

Hyperandrogenism is the most common endocrine disorder in women, characterized by an imbalance of normal estrogen and androgen levels in the blood. Androgens play an important role in the female body because they influence bone mineral density (BMD), body mass composition, muscle mass, mental state, and the regulation of sexual function. The reduced activity of aromatase, due to mutations in the CYP19A1 gene, reduces the estrogen pool in favor of androgens. Clinically, aromatase deficiency causes hyperandrogenism in women. Therefore, the aim of the study was to assess the effect of the CYP19A1 gene polymorphism on selected markers of bone metabolism and hormonal parameters in women with hyperandrogenism. The study group was comprised of 80 young women with hyperandrogenism who underwent measurements of bone mineral density (BMD), and determination of hormonal and metabolic parameters. Enzyme immunoassays were used to measure leptin, total sRANKL (free and bound RANKL), osteoprotegerin, and total 25-OH Vitamin D. An analysis of the CYP19A1 gene polymorphisms was performed using the real-time PCR method. The GG genotype of the CYP19A1 rs700518 polymorphism turned out to be associated with: FEI (Free Estradiol Index), SHGB concentration, estradiol concentration, and insulin concentration determined in the glucose tolerance test 60’ compared to AG and AA genotypes. Patients with the AG genotype had a higher ratio of android to gynoid fat and a greater content of visceral adipose tissue. Higher visceral tissue content may reduce BMD. In conclusion, the study showed that the CYP19A1 rs700518 polymorphism may be associated with the distribution of adipose tissue in young women with hyperandrogenism. These results suggest that patients with the AG genotype may develop osteoporosis.

Role of sex steroids hormones in the regulation of bone metabolism in men: Evidence from clinical studies

Sex steroids regulate bone metabolism in young men during growth and consolidation. Their deficit during growth compromises longitudinal and radial growth of bones and has a negative impact on body height, bone width, peak areal bone mineral density (aBMD) and bone microarchitecture. In older men, the deficit of sex steroid hormones (mainly 17β-oestradiol) contributes to high bone turnover rate, low aBMD, poor bone microarchitecture, low estimated bone strength, accelerated bone loss and rapid decline of bone microarchitecture. The role of 17β-oestradiol is confirmed by the case of men with congenital oestrogen receptor deficit and with congenital aromatase deficiency. 17β-oestradiol inhibits bone resoption, whereas both hormones regulate bone formation. However, the associations are weak. Prospective data on the utility of blood 17β-oestradiol or testosterone for fracture risk assessment are inconsistent. Men with hypogonadism have decreased aBMD and poor bone microarchitecture. In men with hypogonadism, testosterone replacement therapy increases aBMD and improves bone microarchitecture. In men with prostate cancer, androgen deprivation therapy (gonadoliberin analogues) induces rapid bone loss and severe deterioration of bone microarchitecture.

A Novel Homozygous CYP19A1 Gene Mutation Causing Aromatase Deficiency

Aromatase deficiency is a rare autosomal recessive disorder and its exact prevalence is not known. Aromatase enzyme catalyzes the conversion of androgens to estrogens in gonadal and extra-gonadal tissues. Deficiency of aromatase enzyme can lead to ambiguous genitalia in a female child and maternal virilization during pregnancy due to raised androgen levels in the mother. A 10-month-old child was referred to our outpatient department for the evaluation of ambiguous genitalia. There was a history of maternal virilization during pregnancy. Karyotype of the child was 46XX. Congenital adrenal hyperplasia was ruled out as serum cortisol, plasma adrenocorticotropic hormone, and 17-hydroxyprogesterone were within normal limits. Hormonal assays showed elevated follicle-stimulating hormone and luteinizing hormone, with raised testosterone and low estradiol levels. Based on these findings, aromatase deficiency was suspected. A novel homozygous mutation c.1376delA located on exon 10 was identified on the CYP19A1 gene. We identified a novel mutation in the CYP19A1 gene in a patient who presented with ambiguous genitalia and maternal virilization during pregnancy.

Congenital disorders of estrogen biosynthesis and action

Estrogens regulate pubertal development and reproductive function in women, spermatogenesis in men, and bone turnover and metabolic conditions in individuals of both sexes. Estradiol, the major estrogen in humans, is synthesized from testosterone by the action of aromatase and exerts its effects though binding to estrogen receptors. Germline loss- and gain-of-function variants in CYP19A1, the gene encoding aromatase, lead to aromatase deficiency and aromatase excess syndrome, respectively. Germline loss-of-function variants in ESR1, the gene encoding estrogen receptor α, are known to cause of estrogen insensitivity/resistance. In addition, rare variants in ESR1 and ESR2 have been implicated in various disease phenotypes. Clinical studies on these rare endocrine disorders provided clues to understand the biological functions of estrogens in the human body. This review introduces the genetic basis, phenotypes, and current management procedures of congenital disorders in estrogen biosynthesis and action.

Obesity, Body Composition, and Sex Hormones: Implications for Cardiovascular Risk

Cardiovascular disease (CVD) continues to be the leading cause of death in adults, highlighting the need to develop novel strategies to mitigate cardiovascular risk. The advancing obesity epidemic is now threatening the gains in CVD risk reduction brought about by contemporary pharmaceutical and surgical interventions. There are sex differences in the development and outcomes of CVD; premenopausal women have significantly lower CVD risk than men of the same age, but women lose this advantage as they transition to menopause, an observation suggesting potential role of sex hormones in determining CVD risk. Clear differences in obesity and regional fat distribution among men and women also exist. While men have relatively high fat in the abdominal area, women tend to distribute a larger proportion of their fat in the lower body. Considering that regional body fat distribution is an important CVD risk factor, differences in how men and women store their body fat may partly contribute to sex-based alterations in CVD risk as well. This article presents findings related to the role of obesity and sex hormones in determining CVD risk. Evidence for the role of sex hormones in determining body composition in men and women is also presented. Lastly, the clinical potential for using sex hormones to alter body composition and reduce CVD risk is outlined. © 2022 American Physiological Society. Compr Physiol 12:1-45, 2022.

Beyond the X Factor: Relevance of Sex Hormones in NAFLD Pathophysiology

Non-alcoholic fatty liver disease (NAFLD) is a major health issue worldwide, being frequently associated with obesity, unbalanced dietary regimens, and reduced physical activity. Despite their greater adiposity and reduced physical activity, women show a lower risk of developing NAFLD in comparison to men, likely a consequence of a sex-specific regulation of liver metabolism. In the liver, sex differences in the uptake, synthesis, oxidation, deposition, and mobilization of lipids, as well as in the regulation of inflammation, are associated with differences in NAFLD prevalence and progression between men and women. Given the major role of sex hormones in driving hepatic sexual dimorphism, this review will focus on the role of sex hormones and their signaling in the regulation of hepatic metabolism and in the molecular mechanisms triggering NAFLD development and progression.

Aromatase deficiency: A case series of 46, XX Chinese children and a systematic review of the literature

BACKGROUND

Aromatase deficiency (AD) caused by cytochrome P450 family 19 subfamily A polypeptide 1 (CYP19A1) variants is characterized by a deficiency in androgen-to-oestrogen conversion.

OBJECTIVE

To investigate the clinical characteristics and accurate management of aromatase-deficient children.

PATIENTS AND METHODS

We described three 46, XX aromatase-deficient children, searched PubMed with "(aromatase deficiency) AND (46, XX OR ovaries)" and manually searched citations in identified studies for the literature review.

RESULTS

Two girls and one boy (3.4-9.2 years) with the 46, XX karyotype presented ambiguous genitalia and maternal antenatal virilization, normal-low height, delayed bone age, normal glucose and lipid profiles, markedly elevated follicle-stimulating hormone (FSH) levels and poor oestradiol responses to human menopausal gonadotropin stimulation. Ultrasound revealed normal-sized uterus and ovaries with undetectable follicles. Histopathology revealed primordial follicles and few primary follicles in ovaries. One patient presented granulosa and follicular membrane cell proliferation and interstitial sclerosis. We identified four CYP19A1 variants; c.146_158del and c.344G >A were unreported. We reviewed available data from thirty 46, XX patients (0.2-32 years). Some patients were not diagnosed until puberty/adulthood; three were initially misdiagnosed with congenital adrenocortical hyperplasia. The main characteristics were maternal antenatal virilization (21/29), ambiguous genitalia (mainly Prader IV or III, 19/23), delayed bone age (16/17), low bone mass (5/8), markedly elevated FSH levels and ovarian cysts (13/30).

CONCLUSIONS

46, XX AD is easily neglected or misdiagnosed. Ambiguous genitalia, maternal antenatal virilization and markedly elevated FSH levels are important diagnostic indicators. We described two novel variants, new histopathological features of ovaries and an early management strategy.

Non-alcoholic Fatty Liver Disease as a Canonical Example of Metabolic Inflammatory-Based Liver Disease Showing a Sex-Specific Prevalence: Relevance of Estrogen Signaling

There is extensive evidence supporting the interplay between metabolism and immune response, that have evolved in close relationship, sharing regulatory molecules and signaling systems, to support biological functions. Nowadays, the disruption of this interaction in the context of obesity and overnutrition underlies the increasing incidence of many inflammatory-based metabolic diseases, even in a sex-specific fashion. During evolution, the interplay between metabolism and reproduction has reached a degree of complexity particularly high in female mammals, likely to ensure reproduction only under favorable conditions. Several factors may account for differences in the incidence and progression of inflammatory-based metabolic diseases between females and males, thus contributing to age-related disease development and difference in life expectancy between the two sexes. Among these factors, estrogens, acting mainly through Estrogen Receptors (ERs), have been reported to regulate several metabolic pathways and inflammatory processes particularly in the liver, the metabolic organ showing the highest degree of sexual dimorphism. This review aims to investigate on the interaction between metabolism and inflammation in the liver, focusing on the relevance of estrogen signaling in counteracting the development and progression of non-alcoholic fatty liver disease (NAFLD), a canonical example of metabolic inflammatory-based liver disease showing a sex-specific prevalence. Understanding the role of estrogens/ERs in the regulation of hepatic metabolism and inflammation may provide the basis for the development of sex-specific therapeutic strategies for the management of such an inflammatory-based metabolic disease and its cardio-metabolic consequences.

Different levels of estradiol are correlated with sexual dysfunction in adult men

Ejaculatory dysfunction, including premature ejaculation (PE) and delayed ejaculation (DE), as well as erectile dysfunction (ED), constitute the majority of male sexual dysfunction. Despite a fair amount of data on the role of hormones and erection and ejaculation, it is inconclusive due to controversy in the current literature. To explore the correlation of male sexual dysfunction with hormonal profile, 1,076 men between the ages of 19–60 years (mean: 32.12 years) were included in this retrospective case–control study; 507 were categorized as ED, PE and DE groups. Five hundred and sixty-nine men without sexual dysfunction were enrolled in the control group. The background characteristics and clinical features of the four groups were collected and analyzed. The estradiol value was significantly elevated in the ED group than the control group (109.44 ± 47.14 pmol/L vs. 91.88 ± 27.68 pmol/L; P < 0.001). Conversely, the DE group had significantly lower level of estradiol than control did (70.76 ± 27.20 pmol/L vs. 91.88 ± 27.68 pmol/L; P < 0.001). The PE group had similar level of estradiol (91.73 ± 31.57 pmol/L vs. 91.88 ± 27.68 pmol/L; P = 0.960) but significantly higher level of testosterone (17.23 ± 5.72 nmol/L vs. 15.31 ± 4.31 nmol/L; P < 0.001) compared with the control group. In conclusion, elevated serum testosterone concentration was an independent risk factor for PE. Besides, there was a progressively increasing graded-distribution of estradiol values from DE to PE and ED groups.

Kinetic Analysis of Lipid Metabolism in Breast Cancer Cells via Nonlinear Optical Microscopy

Investigating the behavior of breast cancer cells via reaction kinetics may help unravel the mechanisms that underlie metabolic changes in tumors. However, obtaining human in vivo kinetic data is challenging because of difficulties associated with measuring these parameters. Nondestructive methods of measuring lipid content in live cells provide a novel approach to quantitatively model lipid synthesis and consumption. In this study, coherent Raman scattering microscopy was used to probe de novo intracellular lipid content. Combining nonlinear optical microscopy and Michaelis-Menten kinetics-based simulations, we isolated fatty acid synthesis/consumption rates and elucidated effects of altered lipid metabolism in T47D breast cancer cells. When treated with 17β-estradiol, the lipid utilization in cancer cells jumped by twofold. Meanwhile, the rate of de novo lipid synthesis in cancer cells treated with 17β-estradiol was increased by 42%. To test the model in extreme metabolic conditions, we treated T47D cells with etomoxir. Our kinetic analysis demonstrated that the rate of key enzymatic reactions dropped by 75%. These results underline the capability to probe lipid alterations in live cells with minimum interruption and to characterize lipid metabolism in breast cancer cells via quantitative kinetic models and parameters.

Novel CYP19A1 Mutations Extend the Genotype-Phenotype Correlation and Reveal the Impact on Ovarian Function

Context

The steroidogenic enzyme aromatase (CYP19A1) is required for estrogen biosynthesis from androgen precursors in the ovary and extragonadal tissues. The role of aromatase, and thus estrogens, is best illustrated by genetic variations of the CYP19A1 gene leading to aromatase deficiency or excess.

Objective

The objective of this work is to characterize novel CYP19A1 variants.

Design setting and patients

Variants causing aromatase deficiency were suspected in four 46,XX children of African and Indian origin by careful clinical phenotyping. Sequencing of the CYP19A1 gene identified novel variants. Minigene experiments, aromatase activity assay, and computational, and histological analysis were used to characterize the variants.

Main outcome measure and results

CYP19A1 variants were found in all patients: a deletion in intron 9 leading to p.P423_H503del, a delins variant at p.P154, and point variants p.V161D, p.R264C, p.R375C. Except for R264C, all variants showed a loss of function. Protein structure and dynamics studies were in line with functional assays. The 2 female patients with delins variants manifested with ambiguous genitalia at birth. Histologic investigation revealed normal ovarian tissue on one side and a streak gonad on the other. Two female patients presented with abnormal pubertal development and polycystic ovaries.

Conclusion

In girls, aromatase deficiency usually manifests at birth, but diagnosis may also be made because of abnormal pubertal development or ovarian torsion due to (poly)cystic ovaries. The ovary harboring CYP19A1 variants may present as streak gonad or appears normal at birth, but is then at very high risk to produce cysts with aging and is therefore prone to ovarian torsion.

Estrogens in Human Male Gonadotropin Secretion and Testicular Physiology From Infancy to Late Puberty

Several reports in humans as well as transgenic mouse models have shown that estrogens play an important role in male reproduction and fertility. Estrogen receptor alpha (ERα) and beta (ERβ) are expressed in different male tissues including the brain. The estradiol-binding protein GPER1 also mediates estrogen action in target tissues. In human testes a minimal ERα expression during prepuberty along with a marked pubertal up-regulation in germ cells has been reported. ERβ expression was detected mostly in spermatogonia, primary spermatocytes, and immature spermatids. In Sertoli cells ERβ expression increases with age. The aromatase enzyme (cP450arom), which converts androgens to estrogens, is widely expressed in human tissues (including gonads and hypothalamus), even during fetal life, suggesting that estrogens are also involved in human fetal physiology. Moreover, cP450arom is expressed in the early postnatal testicular Leydig cells and spermatogonia. Even though the aromatase complex is required for estrogen synthesis, its biological relevance is also related to the regulation of the balance between androgens and estrogens in different tissues. Knockout mouse models of aromatase (ArKO) and estrogen receptors (ERKOα, ERKOβ, and ERKOαβ) provide an important tool to study the effects of estrogens on the male reproductive physiology including the gonadal axis. High basal serum FSH levels were reported in adult aromatase-deficient men, suggesting that estrogens are involved in the negative regulatory gonadotropin feedback. However, normal serum gonadotropin levels were observed in an aromatase-deficient boy, suggesting a maturational pattern role of estrogen in the regulation of gonadotropin secretion. Nevertheless, the role of estrogens in primate testis development and function is controversial and poorly understood. This review addresses the role of estrogens in gonadotropin secretion and testicular physiology in male humans especially during childhood and puberty.

Foetal oestrogens and autism

Elevated latent prenatal steroidogenic activity has been found in the amniotic fluid of autistic boys, based on measuring prenatal androgens and other steroid hormones. To date, it is unclear if other prenatal steroids also contribute to autism likelihood. Prenatal oestrogens need to be investigated, as they play a key role in synaptogenesis and corticogenesis during prenatal development, in both males and females. Here we test whether levels of prenatal oestriol, oestradiol, oestrone and oestrone sulphate in amniotic fluid are associated with autism, in the same Danish Historic Birth Cohort, in which prenatal androgens were measured, using univariate logistic regression (n = 98 cases, n = 177 controls). We also make a like-to-like comparison between the prenatal oestrogens and androgens. Oestradiol, oestrone, oestriol and progesterone each related to autism in univariate analyses after correction with false discovery rate. A comparison of standardised odds ratios showed that oestradiol, oestrone and progesterone had the largest effects on autism likelihood. These results for the first time show that prenatal oestrogens contribute to autism likelihood, extending the finding of elevated prenatal steroidogenic activity in autism. This likely affects sexual differentiation, brain development and function.

Young Coconut Juice Reduces Some Histopathological Changes Associated with Alzheimer's Disease through the Modulation of Estrogen Receptors in Orchidectomized Rat Brains

Propose. This study aimed to evaluate the protective role of young coconut juice (YCJ) against the pathological changes in Alzheimer's disease (AD) in orchidectomized (orx) rats. Methods and Results. Animals were divided into 7 groups including: baseline normal control group, sham control, orx rat group, orx rat group injected with 2.5 μg/kg b.w. estradiol benzoate (EB) 3 days a week for 10 weeks, and the orx rat groups treated orally with 10, 20, and 40 ml/kg b.w. of YCJ for 10 weeks. At the end of treatment period, animals were sacrificed and the brain of each rat was removed, fixed in 10% neutral formalin, and stained by specific antibodies against NF200, parvalbumin (PV), β-amyloid (Aβ), and estrogen receptors (ERα and ERβ). The results showed that the number of NF200- and PV-reactive neurons in the hippocampus and cerebral cortex was significantly reduced in orx rats. However, it restored to normal in orx rats injected with EB or those administrated with YCJ in a dose-related manner. Neurons containing β-amyloid (Aβ), a hallmark of Alzheimer's disease (AD), were found to be increased in the orx rats; however; they were reduced by EB injection or YCJ administration. These results suggested the binding of the YCJ active ingredient(s) with estrogen receptors (ERs) in the brain as indicated by the detection of ERα and ERβ in neurons since a significant correlation was detected between NF200-/PV-reactive neurons vs ERα-/ERβ-reactive neurons.Conclusion. It could be concluded that YCJ is effective as EB in reducing AD pathology, probably by being selective estrogen receptor modulators.

A Novel Homozygous CYP19A1 Gene Mutation: Aromatase Deficiency Mimicking Congenital Adrenal Hyperplasia in an Infant without Obvious Maternal Virilisation

Aromatase deficiency is a rare, autosomal recessive disorder in which affected patients fail to synthesize normal estrogen. Herein, we report a 46, XX patient born with virilised external genitalia. A novel homozygous mutation in the CYP19A1 gene, causing aromatase deficiency, was detected. A 30-day infant registered as a male was referred to pediatric endocrinology because of a uterus detected on ultrasonography. The infant was born at 23 gestational weeks by C-section because of preeclampsia and premature membrane rupture. The parents were consanginenous. There was no evidence of virilisation, such as acne, hirsutism, deep voice or clitoral enlargement in the maternal history. Physical examination of the infant revealed complete scrotal fusion and a single urogenital meatus, consistent with Prader stage-3. A standard dose adrenocorticotropic hormone (ACTH) test revealed an inadequate cortisol response and high 17-hydroxy progesterone levels, suggesting simple virilising congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. However, no mutation in the CYP21A2 gene was detected. At age 2.5 years the ACTH test was repeated, after suspension of hydrocortisone treatment for 48 hours, when resulting cortisol and androgen levels were normal. The patient was re-evaluated in terms of 46, XX disorders of sex development (DSD), especially with a suspicion of aromatase deficiency. A novel, homozygous, exon 6 deletion was identified in the CYP19A1 gene. Aromatase deficiency may be confused with CAH in the newborn period. In this case 46, XX DSD aromatase deficiency was present in the absence of a history of maternal virilisation or large and multicystic ovaries.

Clinical Management of Congenital Hypogonadotropic Hypogonadism

The initiation and maintenance of reproductive capacity in humans is dependent on pulsatile secretion of the hypothalamic hormone GnRH. Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder that results from the failure of the normal episodic GnRH secretion, leading to delayed puberty and infertility. CHH can be associated with an absent sense of smell, also termed Kallmann syndrome, or with other anomalies. CHH is characterized by rich genetic heterogeneity, with mutations in >30 genes identified to date acting either alone or in combination. CHH can be challenging to diagnose, particularly in early adolescence where the clinical picture mirrors that of constitutional delay of growth and puberty. Timely diagnosis and treatment will induce puberty, leading to improved sexual, bone, metabolic, and psychological health. In most cases, patients require lifelong treatment, yet a notable portion of male patients (∼10% to 20%) exhibit a spontaneous recovery of their reproductive function. Finally, fertility can be induced with pulsatile GnRH treatment or gonadotropin regimens in most patients. In summary, this review is a comprehensive synthesis of the current literature available regarding the diagnosis, patient management, and genetic foundations of CHH relative to normal reproductive development.

Aromatase Deficiency due to a Novel Mutation in CYP19A1 Gene

Aromatase deficiency is a rare autosomal recessive genetic disorder with an unknown incidence. Aromatase converts androgens into estrogen in the gonadal and extra-gonadal tissues. Aromatase deficiency causes ambiguous genitalia in the female fetus and maternal virilization (hirsutism, acne, cliteromegaly, deep voice) during pregnancy due to increased concentration of androgens. A 19 months old girl patient was assessed due to presence of ambiguous genitalia. There were findings of maternal virilization during pregnancy. The karyotype was 46,XX. Congenital adrenal hyperplasia was not considered since adrenocorticotropic hormone, cortisol, and 17-hydroxyprogesterone levels were within normal ranges. At age two months, follicle-stimulating hormone and total testosterone levels were elevated and estradiol level was low. Based on these findings, aromatase deficiency was suspected. A novel homozygous mutation IVS7-2A>G (c.744-2A>G) was identified in the CYP19A1 gene. Pelvic ultrasound showed hypoplasic ovaries rather than large and cystic ovaries. We identified a novel mutation in the CYP19A1 gene in a patient who presented with ambiguous genitalia and maternal virilization during pregnancy. Presence of large and cystic ovaries is not essential in aromatase deficiency.

Age-related mechanical strength evolution of trabecular bone under fatigue damage for both genders: Fracture risk evaluation

Bone tissue is a living composite material, providing mechanical and homeostatic functions, and able to constantly adapt its microstructure to changes in long term loading. This adaptation is conducted by a physiological process, known as "bone remodeling". This latter is manifested by interactions between osteoclasts and osteoblasts, and can be influenced by many local factors, via effects on bone cell differentiation and proliferation. In the current work, age and gender effects on damage rate evolution, throughout life, have been investigated using a mechanobiological finite element modeling. To achieve the aim, a mathematical model has been developed, coupling both cell activities and mechanical behavior of trabecular bone, under cyclic loadings. A series of computational simulations (ABAQUS/UMAT) has been performed on a 3D human proximal femur, allowing to investigate the effects of mechanical and biological parameters on mechanical strength of trabecular bone, in order to evaluate the fracture risk resulting from fatigue damage. The obtained results revealed that mechanical stimulus amplitude affects bone resorption and formation rates, and indicated that age and gender are major factors in bone response to the applied loadings.

Aromatase in normal and diseased liver

Background A potential correlation between sex hormones, such as androgens and estrogens, and the development and progression of hepatocellular carcinoma (HCC) has been proposed. However, its details, in particular, aromatase status in diseased human liver has remained largely unknown. Materials and methods We immunolocalized aromatase, 17β-hydroxysteroid dehydrogenase (17β-HSD) type 1 and 17β-HSD type 2 in a total of 155 cases, consisting of normal liver (n = 10), nonalcoholic steatohepatitis (NASH) (n = 18), primary sclerosing cholangitis (PSC) (n = 6), primary biliary cholangitis (PBC) (n = 13), biliary atresia (n = 18), alcoholic hepatitis (n = 11), hepatitis C virus (HCV) (n = 31), HCV sustained virologic response (HCV-SVR) (n = 10), hepatitis B virus (HBV) (n = 20), HBV sustained virologic response (HBV-SVR) (n = 8) and infants (n = 10). Results Immunoreactivity scores of aromatase in HBV (59.5 ± 30.9), HBV-SVR (68.1 ± 33.5) and infants (100.5 ± 36.6) were significantly higher than those in normal liver (26.0 ± 17.1). Scores of 17β-HSD type 1 in any etiology other than HBV (116.3 ± 23.7) and infants (120.0 ± 28.5) were significantly lower than those in normal liver (122.5 ± 8.6). Scores of 17β-HSD type 2 in NASH (74.4 ± 36.6) were significantly lower than those in normal liver (128.0 ± 29.7). Conclusion High immunoreactivity scores of aromatase and 17β-HSD type 1 in the patients with HBV suggest a correlation between HBV infection and in situ estrogen synthesis in hepatocytes.

Estrogens in Male Physiology

Estrogens have historically been associated with female reproduction, but work over the last two decades established that estrogens and their main nuclear receptors (ESR1 and ESR2) and G protein-coupled estrogen receptor (GPER) also regulate male reproductive and nonreproductive organs. 17β-Estradiol (E2) is measureable in blood of men and males of other species, but in rete testis fluids, E2 reaches concentrations normally found only in females and in some species nanomolar concentrations of estrone sulfate are found in semen. Aromatase, which converts androgens to estrogens, is expressed in Leydig cells, seminiferous epithelium, and other male organs. Early studies showed E2 binding in numerous male tissues, and ESR1 and ESR2 each show unique distributions and actions in males. Exogenous estrogen treatment produced male reproductive pathologies in laboratory animals and men, especially during development, and studies with transgenic mice with compromised estrogen signaling demonstrated an E2 role in normal male physiology. Efferent ductules and epididymal functions are dependent on estrogen signaling through ESR1, whose loss impaired ion transport and water reabsorption, resulting in abnormal sperm. Loss of ESR1 or aromatase also produces effects on nonreproductive targets such as brain, adipose, skeletal muscle, bone, cardiovascular, and immune tissues. Expression of GPER is extensive in male tracts, suggesting a possible role for E2 signaling through this receptor in male reproduction. Recent evidence also indicates that membrane ESR1 has critical roles in male reproduction. Thus estrogens are important physiological regulators in males, and future studies may reveal additional roles for estrogen signaling in various target tissues.

Menopausal Hormone Therapy and Type 2 Diabetes Prevention: Evidence, Mechanisms, and Clinical Implications

Type 2 diabetes has reached epidemic proportions in the United States. Large, randomized controlled trials suggest that menopausal hormone therapy (MHT) delays the onset of type 2 diabetes in women. However, the mechanisms and clinical implications of this association are still a matter of controversy. This review provides an up-to-date analysis and integration of epidemiological, clinical, and basic studies, and proposes a mechanistic explanation for the effect of menopause and MHT on type 2 diabetes development and prevention. We discuss the beneficial effects of endogenous estradiol with respect to insulin secretion, insulin sensitivity, and glucose effectiveness; we also discuss energy expenditure and adipose distribution, both of which are affected by menopause and improved by MHT, which thereby decreases the incidence of type 2 diabetes. We reconcile differences among studies that investigated the effect of menopause and MHT formulations on type 2 diabetes. We argue that discrepancies arise from physiological differences in methods used to assess glucose homeostasis, ranging from clinical indices of insulin sensitivity to steady-state methods to assess insulin action. We also discuss the influence of the route of estrogen administration and the addition of progestogens. We conclude that, although MHT is neither approved nor appropriate for the prevention of type 2 diabetes due to its complex balance of risks and benefits, it should not be withheld from women with increased risk of type 2 diabetes who seek treatment for menopausal symptoms.

Male Hypogonadism and Osteoporosis: The Effects, Clinical Consequences, and Treatment of Testosterone Deficiency in Bone Health

It is well recognized that bone loss accelerates in hypogonadal states, with female menopause being the classic example of sex hormones affecting the regulation of bone metabolism. Underrepresented is our knowledge of the clinical and metabolic consequences of overt male hypogonadism, as well as the more subtle age-related decline in testosterone on bone quality. While menopause and estrogen deficiency are well-known risk factors for osteoporosis in women, the effects of age-related testosterone decline in men on bone health are less well known. Much of our knowledge comes from observational studies and retrospective analysis on small groups of men with variable causes of primary or secondary hypogonadism and mild to overt testosterone deficiencies. This review aims to present the current knowledge of the consequences of adult male hypogonadism on bone metabolism. The direct and indirect effects of testosterone on bone cells will be explored as well as the important differences in male osteoporosis and assessment as compared to that in females. The clinical consequence of both primary and secondary hypogonadism, as well as testosterone decline in older males, on bone density and fracture risk in men will be summarized. Finally, the therapeutic options and their efficacy in male osteoporosis and hypogonadism will be discussed.

Aromatase deficiency in a male patient - Case report and review of the literature

OBJECTIVE

Aromatase, or CYP19A1, is a type II cytochrome CYP450 enzyme that catalyzes the conversion of C19 androgens to C18 estrogens. Its crucial role in both female and male physiology has been deduced from human and animal studies using aromatase inhibitors, genetically altered mice, and patients with aromatase deficiency. The latter is an extremely rare disorder. Its diagnosis is particularly difficult in males, who go through puberty normally and therefore usually present as adults with elevated testosterone, bone abnormalities (e.g., delayed bone age and low bone mass), and metabolic syndrome. In this report, we describe a new case of a male patient with aromatase deficiency harboring a known mutation who presented with less severe clinical and biochemical features.

CASE REPORT

The patient presented with low bone mass and delayed bone age after a finger fracture at age 25years. FSH, LH and testosterone levels were normal, but estradiol and estrone levels were absent or barely detectable, raising suspicion for aromatase deficiency. A homozygous c.628G>A mutation in exon 5 was confirmed by direct sequencing. Unlike previously reported cases of aromatase deficiency, he did not display biochemical features of insulin resistance, dyslipidemia, or overweight/obese status. Therapy with estradiol led to the closure of growth plates and a dramatic increase in bone mass.

CONCLUSIONS

Here we explore genotype/phenotype associations of this new case compared to cases reported previously. We conclude that the specific nature of mutation c.628G>A, which can potentially result in several different forms of the aromatase enzyme, may lend an explanation to the variable phenotypes associated with this particular genotype.

Aromatase deficiency: a novel compound heterozygous mutation identified in a Chinese girl with severe phenotype and obvious maternal virilization

BACKGROUND

Aromatase deficiency is a rare autosomal recessive disorder that is caused by an impairment of androgen conversion to estrogens. Affected 46, XX individuals generally present with virilization of external genitalia at birth and mutations in CYP19A1 gene.

OBJECTIVE

This study described the clinical features and molecular basis of a Chinese 46, XX girl born with ambiguous genitalia and investigated the functional alteration of two novel mutations of the CYP19A1 gene.

METHODS AND RESULTS

Obvious prepartum virilization and remarkably elevated testosterone were observed in the mother, who was initially suspected to have a testosterone-producing ovarian tumor. Clinical phenotypes and hormone profiles of the patient and her mother were investigated. Genotyping analyses of the CYP19A1 gene were performed in the patient and her parents. Functional impairment of the mutations was explored using three-dimensional computer model and mutagenesises in vitro transfection assays. A compound heterozygous mutation of the CYP19A1 gene was revealed in the patient, with a G deletion in nucleotide 264 of exon 3 in one allele and a 23-bp insertion in exon 9 in another allele; both mutations resulted in reading frame-shifts that led to truncated proteins of 87 and 360 amino acids, respectively. Molecular modeling analysis suggested that the two renascent truncated proteins lacked crucial amino acids that were involved in substrate access and catalysis as well as heme-binding region. Functional studies in transfected HEK-293T cells exhibited a nearly complete abolishment of enzyme activity, which may underlie the phenotype and hormone profile.

CONCLUSIONS

Two novel CYP19A1 mutations were identified in a Chinese girl born with ambiguous genitalia and severe maternal virilization during pregnancy. Maternal virilization should prompt consideration of aromatase deficiency, preventing unnecessary interventions in pregnancy. This study broadens the spectrum of phenotype and genetic mutations of this rare disorder.

Structural and functional characterization of aromatase, estrogen receptor, and their genes in endocrine-responsive and -resistant breast cancer cells

Aromatase and estrogen receptor α (ER) are two key proteins for the proliferation of endocrine-responsive and -resistant breast cancers. Aromatase is an enzyme involved in the conversion of androgen (such as testosterone) to estrogen (such as 17β-estradiol). It is also a very effective therapeutic target for the treatment of endocrine-responsive breast cancer. Comparing endocrine-responsive and -resistant breast cancer, aromatase protein levels do not change significantly. Aromatase activity; however, can be increased via PI3K/Akt/IGFR signaling pathways in endocrine resistant cells. The activity of aromatase has been reported to be modulated by phosphorylation. The ER is an important steroid nuclear receptor in the proliferation of both endocrine-responsive and -resistant cells. Although the mutation or amplification of ER can cause endocrine resistance, it is not commonly found. Some point mutations and translocation events have been characterized and shown to promote estrogen-independent growth. Phosphorylation by cross-talk with growth factor pathways is one of the main mechanisms for ligand-independent activation of ER. Taken together, both ER and aromatase are important in ER-dependent breast cancer and the development of endocrine resistance.

Cell-Based High-Throughput Screening for Aromatase Inhibitors in the Tox21 10K Library

Multiple mechanisms exist for endocrine disruption; one nonreceptor-mediated mechanism is via effects on aromatase, an enzyme critical for maintaining the normal in vivo balance of androgens and estrogens. We adapted the AroER tri-screen 96-well assay to 1536-well format to identify potential aromatase inhibitors (AIs) in the U.S. Tox21 10K compound library. In this assay, screening with compound alone identifies estrogen receptor alpha (ERα) agonists, screening in the presence of testosterone (T) identifies AIs and/or ERα antagonists, and screening in the presence of 17β-estradiol (E2) identifies ERα antagonists. Screening the Tox-21 library in the presence of T resulted in finding 302 potential AIs. These compounds, along with 31 known AI actives and inactives, were rescreened using all 3 assay formats. Of the 333 compounds tested, 113 (34%; 63 actives, 50 marginal actives) were considered to be potential AIs independent of cytotoxicity and ER antagonism activity. Structure-activity analysis suggested the presence of both conventional (eg, 1, 2, 4, - triazole class) and novel AI structures. Due to their novel structures, 14 of the 63 potential AI actives, including both drugs and fungicides, were selected for confirmation in the biochemical tritiated water-release aromatase assay. Ten compounds were active in the assay; the remaining 4 were only active in high-throughput screen assay, but with low efficacy. To further characterize these 10 novel AIs, we investigated their binding characteristics. The AroER tri-screen, in high-throughput format, accurately and efficiently identified chemicals in a large and diverse chemical library that selectively interact with aromatase.

Down-regulation of programmed cell death 4 (PDCD4) is associated with aromatase inhibitor resistance and a poor prognosis in estrogen receptor-positive breast cancer

Progression or recurrence due to resistance to aromatase inhibitors (AIs) is a significant clinical problem for a considerable number of patients with breast cancer. Programmed cell death 4 (PDCD4), a tumor suppressor protein, is targeted for degradation during tumor progression. In the current study, we aimed to examine PDCD4 expression and regulation in AI-resistant breast cancer cells, and its association with survival in patients with estrogen receptor (ER)-positive breast cancer. We determined PDCD4 expression levels in AI-resistant breast cancer cell lines and ER-positive breast cancer tumors, investigated the regulation of PDCD4 in AI-resistant breast cancer cell lines, and carried out a Kaplan-Meier survival analysis in two independent cohorts that included a total of 420 patients with ER-positive breast cancer. We found that PDCD4 expression was down-regulated in AI-resistant breast cancer cells, and this down-regulation was inversely correlated with activation of HER2 signaling. Moreover, lower expression of PDCD4 was significantly associated with HER2 positive status in ER-positive breast tumors. Down-regulation of PDCD4 was mediated through up-regulation of HER2 via the mitogen-activated protein kinase (MAPK), protein kinase B (PKB/AKT), and miR-21 in AI-resistant breast cancer cells. MiR-21 inhibitor and the ER down-regulator fulvestrant induced PDCD4 expression and decreased cell proliferation in AI-resistant breast cancer cells. Furthermore, forced overexpression of PDCD4 resensitized AI-resistant cells to AI or hormone deprivation. Finally, we identified that down-regulation of PDCD4 was associated with a lower rate of disease-free survival in patients with ER-positive breast cancer and high histologic grade of breast tumors. In summary, our study shows that expression of PDCD4 is down-regulated by HER2 signaling in AI-resistant breast cancer. Down-regulation of PDCD4 is associated with AI resistance and a poor prognosis in patients with ER-positive breast cancer.

Cross-talk between ER and HER2 regulates c-MYC-mediated glutamine metabolism in aromatase inhibitor resistant breast cancer cells

Resistance to endocrine therapies in hormone receptor (HR)-positive breast cancer is a significant clinical problem for a considerable number of patients. The oncogenic transcription factor c-MYC (hereafter referred to as MYC), which regulates glutamine metabolism in cancer cells, has been linked to endocrine resistance. We were interested in whether MYC-mediated glutamine metabolism is also associated with aromatase inhibitor (AI) resistant breast cancer. We studied the expression and regulation of MYC and the effects of inhibition of MYC expression in both AI sensitive and resistant breast cancer cells. Considering the role of MYC in glutamine metabolism, we evaluated the contribution of glutamine to the proliferation of AI sensitive and resistant cells, and performed RNA-sequencing to investigate mechanisms of MYC-mediated glutamine utilization in AI resistance. We found that glutamine metabolism was independent of estrogen but still required estrogen receptor (ER) in AI resistant breast cancer cells. The expression of MYC oncogene was up-regulated through the cross-talk between ER and human epidermal growth factor receptor 2 (HER2) in AI resistant breast cancer cells. Moreover, the glutamine transporter solute carrier family (SLC) 1A5 was significantly up-regulated in AI resistant breast cancer cells. ER down-regulator fulvestrant inhibited MYC, SLC1A5, glutaminase (GLS) and glutamine consumption in AI resistant breast cancer cells. Inhibition of MYC, SLC1A5 and GLS decreased AI resistant breast cancer cell proliferation. Our study has uncovered that MYC expression is up-regulated by the cross-talk between ER and HER2 in AI resistant breast cancer cells. MYC-mediated glutamine metabolism is associated with AI resistance of breast cancer.