The aromatase excess syndrome is associated with feminization of both sexes and autosomal dominant transmission of aberrant P450 aromatase gene transcription

17α-estradiol, a lifespan-extending compound, attenuates liver fibrosis by modulating collagen turnover rates in male mice

Estrogen signaling is protective against chronic liver diseases, although men and a subset of women are contraindicated for chronic treatment with 17β-estradiol (17β-E2) or combination hormone replacement therapies. We sought to determine if 17α-estradiol (17α-E2), a naturally occurring diastereomer of 17β-E2, could attenuate liver fibrosis. We evaluated the effects of 17α-E2 treatment on collagen synthesis and degradation rates using tracer-based labeling approaches in male mice subjected to carbon tetrachloride (CCl4)-induced liver fibrosis. We also assessed the effects of 17α-E2 on markers of hepatic stellate cell (HSC) activation, collagen cross-linking, collagen degradation, and liver macrophage content and polarity. We found that 17α-E2 significantly reduced collagen synthesis rates and increased collagen degradation rates, which was mirrored by declines in transforming growth factor β1 (TGF-β1) and lysyl oxidase-like 2 (LOXL2) protein content in liver. These improvements were associated with increased matrix metalloproteinase 2 (MMP2) activity and suppressed stearoyl-coenzyme A desaturase 1 (SCD1) protein levels, the latter of which has been linked to the resolution of liver fibrosis. We also found that 17α-E2 increased liver fetuin-A protein, a strong inhibitor of TGF-β1 signaling, and reduced proinflammatory macrophage activation and cytokines expression in the liver. We conclude that 17α-E2 reduces fibrotic burden by suppressing HSC activation and enhancing collagen degradation mechanisms. Future studies will be needed to determine if 17α-E2 acts directly in hepatocytes, HSCs, and/or immune cells to elicit these benefits.

Diagnosis and management of precocious sexual maturation: an updated review

The classic definition of precocious sexual maturation is the development of secondary sexual characteristics before 8 years of age in girls and before 9 years of age in boys. It is classified as central precocious puberty when premature maturation of the hypothalamic-pituitary-gonadal axis occurs, and as peripheral precocious puberty when there is excessive secretion of sex hormones, independent of gonadotropin secretion. Precocious sexual maturation is more common in girls, generally central precocious puberty of idiopathic origin. In boys, it tends to be linked to central nervous system abnormalities. Clinical evaluation should include a detailed history and physical examination, including anthropometric measurements, calculation of growth velocity, and evaluation of secondary sexual characteristics. The main sign to suspect the onset of puberty is breast tissue development (thelarche) in girls and testicular enlargement (≥4 mL) in boys. Hormonal assessment and imaging are required for diagnosis and identification of the etiology. Genetic testing should be considered if there is a family history of precocious puberty or other clinical features suggestive of a genetic syndrome. Long-acting gonadotropin-releasing hormone analogs are the standard of care for central precocious puberty management, while peripheral precocious puberty management depends on the etiology.Conclusion: The aim of this review is to address the epidemiology, etiology, clinical assessment, and management of precocious sexual maturation. What is Known: • The main sign to suspect the onset of puberty is breast tissue development (thelarche) in girls and testicular enlargement (≥4 mL) in boys. The classic definition of precocious sexual maturation is the development of secondary sexual characteristics before 8 years of age in girls and before 9 years of age in boys. • Long-acting gonadotropin-releasing hormone agonist (GnRHa) is the standard of care for CPP management, and adequate hormone suppression results in the stabilization of pubertal progression, a decline in growth velocity, and a decrease in bone age advancement. What is New: • Most cases of precocious sexual maturation are gonadotropin-dependent and currently assumed to be idiopathic, but mutations in genes involved in pubertal development have been identified, such as MKRN3 and DLK1. • A different preparation of long-acting GnRHa is now available: 6-month subcutaneous injection.

Biochemical features of eugonadal patients with idiopathic gynaecomastia: A retrospective cross-sectional study

Patients with idiopathic gynaecomastia have greater BMI and an unfavourable lipid profile compared with age-matched controls. Twenty-five adult eugonadal patients with idiopathic gynaecomastia and 50 age- and BMI-matched controls were selected. Clinical and biochemical parameters and ultrasound testis volume were reviewed retrospectively. Patients and controls differed for no biochemical parameter, except for LH levels, which were 31% higher in patients (p = 0.019), although within the normal range. Compared with controls, patients had a threefold greater rate of elevated LDL-c (p = 0.025). Patients ≥ 25 years had higher levels of serum LDL-c compared with either patients < 25 years (p = 0.006) or controls ≥ 25 years (p = 0.012). In patients, both at bivariate analysis and at linear regression, age correlated positively with total cholesterol and LDL-c, the latter correlated inversely with total testosterone. Negative interactions were found for age and total testosterone with LDL-c, for LH and estradiol to testosterone ratio (E2:T) with LDL-c, and for age and E2:T with total cholesterol. Our data suggest inadequate local androgen action in patients with idiopathic gynaecomastia. This partial androgen resistance might blunt the beneficial effects of testosterone on lipid metabolism. Further studies are needed to verify whether this metabolic derangement impacts the cardiovascular health of these patients.

CYP19A1 gene expression in the peripheral blood of Brazilian women with breast cancer relapse

Background

The CYP19A1 gene, which encodes the enzyme responsible for androgen aromatization into estrogens, may play an important role in breast cancer aggressiveness. However, no study has evaluated CYP19A1 gene expression in the peripheral blood of women with relapsed breast cancer.

Methods

In this cross-sectional study, CYP19A1 gene expression was quantified by RT-PCR in the peripheral blood of 146 women with breast cancer who were first divided into two groups according to the expression of CYP19A1 (low and high); each group had 73 patients. Subsequently, women were divided into two groups: those without recurrence (control, n = 85) and those with recurrence (study, n = 61). Statistical analysis of the data was performed using ANOVA, the Mann-Whitney, Chi-square or Fisher’s exact test (p <  0.05).

Results

There were no significant differences between the relative expression of CYP19A1 mRNA in the low expression group and the high expression group according to the variables studied. There were no significant differences in CYP19A1 gene expression in the study and control groups (p = 0.8461). In the relapse group, CYP19A1 gene expression was significantly higher in the hybrid luminal subtype than in the triple-negative subtype (p = 0.0321), whereas it was significantly lower in HER2-negative cases than in HER2-positive cases (p <  0.0376). Women with locoregional recurrence showed higher expression than women with distant recurrence (p <  0.0001).

Conclusions

The present study found no significant differences between women with high and low expression of the CYP19A1 gene mRNA or between those in the study group and the control group. However, in women with recurrence, there was increased expression of CYP19A1 mRNA in those who had the luminal hybrid subtype and locoregional relapse and decreased expression in those negative for HER2.

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.

Combined surgical and medical treatment in an adolescent with severe gynecomastia due to excessive estradiol secretion: a case report

Background

Gynecomastia develops due to the reversed estradiol-to-Testosterone ratio in adolescence, and symptoms typically improve within 2 years. The causes vary widely, including estrogen excess and tumors, and surgical treatment is usually given in late adolescence because postoperative symptoms may recur in adolescents. This study reports a case of a pediatric patient with severe gynecomastia due to excessive estradiol secretion who showed a positive outcome after receiving surgical treatment combined with aromatase inhibitor administration.

Case presentation

A 9-year old boy visited to the Department of Pediatric Endocrinology for breast budding. At that time, the patient showed breasts at Tanner stage II and no abnormality on hormone tests. During a follow-up, both gynecomastia had progressed to Tanner stage III–IV at age 13. Tamoxifen 10 mg bid was administered; however, the condition rapidly progressed to Tanner stage V at 13.5 years. The evaluation of pathologic gynecomastia showed an increase of estradiol to 296 pg/mL with normal range 10 ~ 36 pg/mL and microlithiasis in both testes. As the condition worsened, total mastectomy was performed at the age of 13.5 years. Based on the assessment that elevated aromatase activity had induced breast budding, we changed the medication to anastrozole (Arimidex) 1 mg once a day, after which the estradiol level improved to 38.5 pg/mL and was maintained well in the two-year postoperative follow-up.

Conclusions

This case report shows a combined plastic surgery and appropriate medical management bring a positive outcome in severe gynecomastia patient.

Skin steroidogenesis in health and disease

The skin is an important extra-gonadal steroidogenic organ, capable of metabolizing various hormones from their precursors, as well as of synthesizing de novo a broad palette of sex steroids and glucocorticoids from cholesterol. In this manuscript, we review the major steroidogenic properties of human skin and we suggest steroidogenesis' impairment as a cardinal factor for various pathological conditions such as acne, rosacea, atopic dermatitis, and androgenic alopecia.

17α-Estradiol Alleviates Age-related Metabolic and Inflammatory Dysfunction in Male Mice Without Inducing Feminization

Aging is associated with visceral adiposity, metabolic disorders, and chronic low-grade inflammation. 17α-estradiol (17α-E2), a naturally occurring enantiomer of 17β-estradiol (17β-E2), extends life span in male mice through unresolved mechanisms. We tested whether 17α-E2 could alleviate age-related metabolic dysfunction and inflammation. 17α-E2 reduced body mass, visceral adiposity, and ectopic lipid deposition without decreasing lean mass. These declines were associated with reductions in energy intake due to the activation of hypothalamic anorexigenic pathways and direct effects of 17α-E2 on nutrient-sensing pathways in visceral adipose tissue. 17α-E2 did not alter energy expenditure or excretion. Fasting glucose, insulin, and glycosylated hemoglobin were also reduced by 17α-E2, and hyperinsulinemic-euglycemic clamps revealed improvements in peripheral glucose disposal and hepatic glucose production. Inflammatory mediators in visceral adipose tissue and the circulation were reduced by 17α-E2. 17α-E2 increased AMPKα and reduced mTOR complex 1 activity in visceral adipose tissue but not in liver or quadriceps muscle, which is in contrast to the generalized systemic effects of caloric restriction. These beneficial phenotypic changes occurred in the absence of feminization or cardiac dysfunction, two commonly observed deleterious effects of exogenous estrogen administration. Thus, 17α-E2 holds potential as a novel therapeutic for alleviating age-related metabolic dysfunction through tissue-specific effects.

Prepubertal unilateral gynecomastia: report of 2 cases

Prepubertal unilateral gynecomastia is an extremely rare condition. At present, its etiology and management strategy are not well known. Two unrelated prepubertal boys of ages 8 and 9 who presented with complaints of unilateral enlargement of breast tissue are reported. Physical examination, biochemical, hormonal and oncologic work-up findings were normal. Both patients were treated with peripheral liposuction successfully. Histopathological and immunohistochemical examinations showed benign fibroglandular gynecomastia and intensive (3+) estrogen receptor expression in 100% of periductal epithelial cells. Although an extremely rare and generally benign condition, patients with prepubertal unilateral gynecomastia should have a full endocrine and oncologic work-up.

Prepubertal unilateral gynecomastia in the absence of endocrine abnormalities

Gynecomastia is defined as the excessive development of breast tissue in males, which can occur as unilateral or bilateral. Although the overall prevalence of gynecomastia is 40%-65%, the prepubertal unilateral gynecomastia in the absence of endocrine abnormalities is unusual, with only a few case reports in literature. Idiopathic gynecomastia in prepuberty is benign but a diagnosis of exclusion. We here report two cases of healthy prepubertal boys aged 8.8 and 9.6 years old, respectively, presented with painful palpable mass in their unilateral breast. Breast tissue with glandular proliferation was confirmed on ultrasonography. Serum levels of estradiol, testosterone, and other laboratory findings were within normal range. They seem to have the prepubertal idiopathic gynecomastia but further follow-up to see their progression is needed.

Understanding the pathological manifestations of aromatase excess syndrome: lessons for clinical diagnosis

CYP19A1

Aromatase excess syndrome is characterized by pre- or peripubertal onset of gynecomastia due to estrogen excess because of a gain-of-function mutation in the aromatase gene (CYP19A1). Subchromosomal recombination events including duplication, deletion, and inversion has been identified. The latter two recombinations recruit novel promoters for CYP19A1 through a unique mechanism. Gynecomastia continues for life, and although the general condition is well preserved, it may cause psychological issues. Minor symptoms (variably advanced bone age and short adult height), if present, are exclusively because of estrogen excess. Serum estradiol levels are elevated in 48% of affected males, but are not necessarily useful for diagnosis. Molecular analysis of CYP19A1 mutations is mandatory to confirm aromatase excess syndrome diagnosis. Furthermore, the use of an aromatase inhibitor can ameliorate gynecomastia.

Aromatase excess syndrome presenting with prepubertal gynecomastia in an Egyptian child with type 1 neurofibromatosis

A romatase excess syndrome (AEXS) is a rare autosomal dominant disorder characterized by prepubertal gynecomastia, it responds well to medical treatment. In the absence of prompt suspicion, it can expose the patient to the risk of unnecessary surgical intervention. Up to our best knowledge, the association between AEXS and neurofibromatosis type 1 (NF1) was not reported before. Here, we describe a AEXS presenting with prepubertal gynecomastia in an Egyptian child with NF1 that improved with aromatase inhibitors.

Genetic variations in the androgen receptor are associated with steroid concentrations and anthropometrics but not with muscle mass in healthy young men

Objective

The relationship between serum testosterone (T) levels, muscle mass and muscle force in eugonadal men is incompletely understood. As polymorphisms in the androgen receptor (AR) gene cause differences in androgen sensitivity, no straightforward correlation can be observed between the interindividual variation in T levels and different phenotypes. Therefore, we aim to investigate the relationship between genetic variations in the AR, circulating androgens and muscle mass and function in young healthy male siblings.

Design

677 men (25–45 years) were recruited in a cross-sectional, population-based sibling pair study.

Methods

Relations between genetic variation in the AR gene (CAGn, GGNn, SNPs), sex steroid levels (by LC-MS/MS), body composition (by DXA), muscle cross-sectional area (CSA) (by pQCT), muscle force (isokinetic peak torque, grip strength) and anthropometrics were studied using linear mixed-effect modelling.

Results

Muscle mass and force were highly heritable and related to age, physical activity, body composition and anthropometrics. Total T (TT) and free T (FT) levels were positively related to muscle CSA, whereas estradiol (E₂) and free E₂ (FE₂) concentrations were negatively associated with muscle force. Subjects with longer CAG repeat length had higher circulating TT, FT, and higher E₂ and FE₂ concentrations. Weak associations with TT and FT were found for the rs5965433 and rs5919392 SNP in the AR, whereas no association between GGN repeat polymorphism and T concentrations were found. Arm span and 2D:4D finger length ratio were inversely associated, whereas muscle mass and force were not associated with the number of CAG repeats.

Conclusions

Age, physical activity, body composition, sex steroid levels and anthropometrics are determinants of muscle mass and function in young men. Although the number of CAG repeats of the AR are related to sex steroid levels and anthropometrics, we have no evidence that these variations in the AR gene also affect muscle mass or function.

The Relationship between Uterine Myoma Growth and the Endocrine Disruptor in Postmenopausal Women

Objectives

To investigate the number of leiomyoma patients-exposed to bisphenol A (BPA) and to observe whether the serum concentration of BPA is related to leiomyoma growth.

Methods

A total of 158 patients were recruited for this study. Leiomyoma patients were divided into three groups, mild (n = 48), moderate (n = 32) and severe (n = 28), according to the size of leiomyomas. The control (n = 30) group was defined as having no leiomyomas. Transvaginal ultrasonography was used to identify and measure the leiomyomas. Serum BPA concentrations were measured by enzyme-linked immunosorbent assay.

Results

BPA was detected in 87.0% out of a total of 158 samples, and in 86.0% out of 108 leiomyoma patients. In detail, the detection rates of serum BPA were 88.0% in the control group, 77.2% in the mild group, 90.0% in the moderate group and 96.0% in the severe group. The mean BPA concentration in the control group was 0.558 ± 0.097 ng/mL, the leiomyoma groups, the mean BPA concentrations were 0.274 ± 0.063 ng/mL (mild), 0.346 ± 0.064 ng/mL (moderate) and 0.647 ± 0.039 ng/mL (severe) (P = 0.0003). Values represent the mean ± standard error.

Conclusion

The detection rates of serum BPA in the control and leiomyoma groups were 88.0% and 86.0%, respectively. However, there was no significant difference in the serum BPA concentrations between the control and leiomyoma groups. To verify the effect of BPA on leiomyoma growth, a close and sequential monitoring is recommended for people who are at risk for uterine leiomyoma.

Sexual precocity and its treatment

BACKGROUND

Puberty is a complex and dynamic period in development during which individuals transition from the juvenile to adult state. Regulated by multiple genetic and endocrine controls, it is characterized by somatic growth and sexual maturation. Sexual precocity is defined as the appearance of secondary sexual characteristics before the lower limit of the normal age for pubertal onset.

DATA SOURCES

Based on recent publications and the experience with the disease of our group, we reviewed the normal timing and order of puberty, the definition of sexual precocity, the classification of sexual precocity, the differential diagnosis of sexual precocity, variations in pubertal development, the diagnosis of sexual precocity, and the treatment of sexual precocity.

RESULTS

Sexual precocity can be classified as either gonadotropin-releasing hormone (GnRH)-dependent or GnRH-independent. Regardless of the etiology, sexual precocity causes increased height velocity, somatic development, and skeletal maturation, which may have profound physical and psychological implications.

CONCLUSIONS

The treatment of sexual precocity is focused on its cause and must address both its psychosocial and clinical implications. For GnRH-dependent precocious puberty, GnRH agonists are the main pharmacological agents used. Alternatively, the treatment of disorders causing GnRH-independent sexual precocity is directed toward the underlying abnormality.

Plasma kisspeptin levels in girls with premature thelarche

OBJECTIVE

Premature thelarche (PT) is defined as isolated breast development without secondary sex characteristics in girls below the age of eight. We aimed to determine whether the level of kisspeptin, which plays a role in the release of gonadotropins, is associated with PT.

METHODS

The patient group included children with PT aged 3-8 years (n=20) and the control group included healthy children in the same age range (n=20). Height standard deviation scores (HSDSs), bone maturation and growth velocity were evaluated in the two groups. Basal follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), prolactin (PRL), and sex hormone-binding globulin (SHBG) levels were also measured in the two groups by immunochemiluminometric assay (ICMA). A gonadotropin-releasing hormone (GnRH) test was also conducted in the patient group and the peak levels of FSH and LH were determined. Kisspeptin levels were measured using enzyme immunoassay (EIA).

RESULTS

No differences were found between the groups in terms of age, HSDS, annual growth rate and bone age. While the plasma basal FSH, LH and E2 levels in the patient and control groups did not show statistically significant differences, PRL levels were higher in the patient group (p<0.05). Peak LH response to GnRH test was at the prepubertal level (<5 ng/mL) in patients with PT. In the patient group, kisspeptin levels were significantly higher compared to the levels in the control group (2.96 ± 1.21 ng/dL vs. 1.19 ± 0.41 ng/dL, p<0.05), and kisspeptin levels showed a significant correlation with PRL, FSH, LH, and E2 levels (p<0.05).

CONCLUSIONS

In this study, plasma kisspeptin levels were found to be higher in patients with PT and to show a positive correlation with increased PRL levels. Kisspeptin is one of the neuropeptides that plays a role in the onset of puberty. Our results support the hypothesis that PT may result from the temporary activation of central stimulants.

Molecular bases and phenotypic determinants of aromatase excess syndrome

Aromatase excess syndrome (AEXS) is a rare autosomal dominant disorder characterized by gynecomastia. This condition is caused by overexpression of CYP19A1 encoding aromatase, and three types of cryptic genomic rearrangement around CYP19A1, that is, duplications, deletions, and inversions, have been identified in AEXS. Duplications appear to have caused CYP19A1 overexpression because of an increased number of physiological promoters, whereas deletions and inversions would have induced wide CYP19A1 expression due to the formation of chimeric genes consisting of a noncoding exon(s) of a neighboring gene and CYP19A1 coding exons. Genotype-phenotype analysis implies that phenotypic severity of AEXS is primarily determined by the expression pattern of CYP19A1 and the chimeric genes and by the structural property of the fused exons with a promoter function (i.e., the presence or the absence of a natural translation start codon). These results provide novel information about molecular mechanisms of human genetic disorders and biological function of estrogens.

Aromatase (CYP19) gene variants influence ovarian response to standard gonadotrophin stimulation

PURPOSE

The association of cytochrome P450 aromatase gene CYP19(TTTA) ( n ) polymorphism with ovarian response to FSH stimulation was explored.

METHODS

Three hundred women undergoing medically assisted reproduction and 300 women with at least one spontaneous pregnancy participated in the study. CYP19(TTTA) ( n ) polymorphism was genotyped, while serum hormones were determined. During oocyte retrieval, the follicular size, the follicle and oocyte numbers were recorded.

RESULTS

Six CYP19(TTTA) ( n ) alleles with 7 to 12 repeats were revealed. Women homozygous for long CYP19(TTTA) ( n ) alleles presented with lower serum FSH levels at the third day of the menstrual cycle (p < 0.001) and higher large follicle numbers (p < 0.01), compared to women homozygous for short CYP19(TTTA) ( n ) alleles. The CYP19(TTTA) ( 7 ) allele was associated with higher serum FSH levels (p < 0.003), with lower total follicle (p < 0.02) and large follicle numbers (p < 0.03), while CYP19(TTTA) ( 7 ) allele-carriers presented more frequently with small follicles than CYP19(TTTA) ( 7 ) allele-non carriers (p < 0.01).

CONCLUSIONS

CYP19 genetic variants were associated with ovarian reserve and response to standard gonadotrophin stimulation of women undergoing in vitro fertilization.

Aromatase inhibitors in pediatrics

Aromatase, an enzyme located in the endoplasmic reticulum of estrogen-producing cells, catalyzes the rate-limiting step in the conversion of androgens to estrogens in many tissues. The clinical features of patients with defects in CYP19A1, the gene encoding aromatase, have revealed a major role for this enzyme in epiphyseal plate closure, which has promoted interest in the use of inhibitors of aromatase to improve adult height. The availability of the selective aromatase inhibitors letrozole and anastrozole--currently approved as adjuvant therapy for breast cancer--have stimulated off-label use of aromatase inhibitors in pediatrics for the following conditions: hyperestrogenism, such as aromatase excess syndrome, Peutz-Jeghers syndrome, McCune-Albright syndrome and functional follicular ovarian cysts; hyperandrogenism, for example, testotoxicosis (also known as familial male-limited precocious puberty) and congenital adrenal hyperplasia; pubertal gynecomastia; and short stature and/or pubertal delay in boys. Current data suggest that aromatase inhibitors are probably effective in the treatment of patients with aromatase excess syndrome or testotoxicosis, partially effective in Peutz-Jeghers and McCune-Albright syndrome, but probably ineffective in gynecomastia. Insufficient data are available in patients with congenital adrenal hyperplasia or functional ovarian cysts. Although aromatase inhibitors appear effective in increasing adult height of boys with short stature and/or pubertal delay, safety concerns, including vertebral deformities, a decrease in serum HDL cholesterol levels and increase of erythrocytosis, are reasons for caution.

Teasing out the role of aromatase in the healthy and diseased testis

Scientific discoveries over the past decade have shifted the stereotypical view of androgens as male hormones and estrogens as female hormones. It is now recognized that a delicate balance of both androgens and estrogens, a process controlled by aromatase, is fundamental for normal testicular development and fertility. While the site-specific actions of these two classes of steroids within the testis are becoming better documented, the role and regulation of estrogen biosynthesis by aromatase within the testis remains unclear. The majority of data comes from a wide range of animal species, particularly genetically modified mouse models; aromatase knockout (ArKO) and overexpressing (AROM(+)), with limited information on humans, however the existence of congenital aromatase mutations has provided some insight into its effects on individual parameters of the testis. This review dissects out the localization and activity of aromatase in the healthy and diseased testis, addresses the cellular insult to the testis that occurs in its absence and over abundance and proposes potential molecular mechanisms of aromatase regulation in the testis.

Aromatase inhibitors in men: effects and therapeutic options

Aromatase inhibitors effectively delay epiphysial maturation in boys and improve testosterone levels in adult men Therefore, aromatase inhibitors may be used to increase adult height in boys with gonadotropin-independent precocious puberty, idiopathic short stature and constitutional delay of puberty. Long-term efficacy and safety of the use of aromatase inhibitors has not yet been established in males, however, and their routine use is therefore not yet recommended.

The association of aromatase (CYP19) gene variants with sperm concentration and motility

The irreversible transformation of androgens into oestrogens is catalysed by cytochrome P450 aromatase. In the present study, we explored the contribution of the (TTTA)(n) polymorphism in the aromatase gene (CYP19) to sperm concentration and motility. Ninety normozoospermic and 60 oligospermic men were examined during infertility examinations. DNA was extracted from spermatozoa, and the CYP19 (TTTA)(n) polymorphism was genotyped by PCR. Genotype analysis revealed six CYP19 (TTTA)(n) alleles with 7-12 repeats. The allelic distribution of the CYP19 (TTTA)(n) polymorphism differed between normozoospermic and oligospermic men (P<0.01). Oligospermic men less frequently had long CYP19 alleles than did normozoospermic men (25 and 37.8%, respectively; P<0.02). The higher frequency of short CYP19 alleles in oligospermic men compared to normozoospermic men (43.3 and 28.3%, respectively; P<0.01) was primarily due to the distribution of the CYP19 (TTTA)(7) allele. The CYP19 (TTTA)(7) allele was associated with lower sperm concentration in normozoospermic men (P<0.01) and in the total study population (P<0.01); it was also associated with lower sperm motility in normozoospermic men (P<0.05) and in the total study population (P<0.01). In conclusion, the CYP19 (TTTA)(7) allele probably impairs aromatase activity, which in turn alters aromatase and oestrogen levels in the testis, leading to decreased sperm concentration and motility. These findings support the significance of cytochrome P450 aromatase in human spermatogenesis and consequently in semen quality.

Defects of steroidogenesis

In the biosynthesis of steroid hormones the neutral lipid cholesterol, a normal constituent of lipid bilayers is transformed via a series of hydroxylation, oxidation, and reduction steps into a vast array of biologically active compounds: mineralocorticoids, glucocorticoids, and sex hormones. Glucocorticoids regulate many aspects of metabolism and immune function, whereas mineralocorticoids help maintain blood volume and control renal excretion of electrolytes. Sex hormones are essential for sex differentiation in male and support reproduction. They include androgens, estrogens, and progestins. A block in the pathway of steroid biosynthesis leads to the lack of hormones downstream and accumulation of the upstream compounds that can activate other members of the steroid receptor family. This review deals with the clinical consequences of these blocks.

Intrauterine growth retardation associated with precocious puberty and sertoli cell hyperplasia

The original description of patients with Russell-Silver syndrome included precocious puberty, the mechanism of which was unclear. We describe a child with a Russell-Silver syndrome-like phenotype who presented with precocious puberty that was associated with hyperplasia of the Sertoli cells. The patient was found to have an immature cryptorchid testicle; hyperplastic Sertoli cells were also aneuploid carrying trisomy 8. This chromosomal abnormality was present in Sertoli cells only and could not be detected in peripheral lymphocytes, tunica vaginalis, or other, normal, testicular tissue. Sertoli cells in culture showed excess aromatization providing an explanation for the rapid advancement of the patient's bone age. We conclude that in a patient with a Russell-Silver syndrome-like phenotype, Sertoli cell hyperplasia was associated with somatic trisomy 8, increased aromatization, and gonadotropin-independent precocious puberty.

Prepubertal unilateral gynecomastia: a report of two cases

Background

Gynecomastia is defined as the presence of excessive breast tissue in males, which can appear unilateral or bilateral. Bilateral gynecomastia is frequently found in the neonatal period, early in puberty, and with increasing age. Prepubertal unilateral gynecomastia in the absence of endocrine abnormalities is extremely rare, with only a few cases in literature.

Methods

We report the cases of two otherwise healthy boys of 8 and 11 years old with unilateral breast masses. No abnormalities were found on ultrasonography and all endocrine parameters were within normal limits. Treatment consisted of peripheral liposuction followed by subcutaneous partial resection of the gland, conducted through an infra-areolar incision.

Results

Microscopy of the subcutaneous mastectomy specimen revealed gynecomastia without signs of malignancy. Postoperative course of both patients was uncomplicated, with no signs of recurrence of breast tissue.

Conclusions

Atypical presentations of gynecomastia are often not recognized, with little attention to breast development in prepubertal non-obese children. Since prepubertal gynecomastia could be a sign of possible underlying diseases, a thorough examination and further research is recommended. If there is no causal treatment, surgical resection is the therapy of first choice. Peripheral liposuction and surgical resection of the gland tissue are the mainstay of treatment. In summary, we describe two cases of prepubertal unilateral gynecomastia with a normal endocrine workup. Further research is needed to establish the pathophysiologic mechanisms of prepubertal gynecomastia, since underlying etiology in most cases remains unclear.

Cytochromes P450: a success story

SUMMARY

Cytochrome P450 proteins, named for the absorption band at 450 nm of their carbon-monoxide-bound form, are one of the largest superfamilies of enzyme proteins. The P450 genes (also called CYP) are found in the genomes of virtually all organisms, but their number has exploded in plants. Their amino-acid sequences are extremely diverse, with levels of identity as low as 16% in some cases, but their structural fold has remained the same throughout evolution. P450s are heme-thiolate proteins; their most conserved structural features are related to heme binding and common catalytic properties, the major feature being a completely conserved cysteine serving as fifth (axial) ligand to the heme iron. Canonical P450s use electrons from NAD(P)H to catalyze activation of molecular oxygen, leading to regiospecific and stereospecific oxidative attack of a plethora of substrates. The reactions carried out by P450s, though often hydroxylation, can be extremely diverse and sometimes surprising. They contribute to vital processes such as carbon source assimilation, biosynthesis of hormones and of structural components of living organisms, and also carcinogenesis and degradation of xenobiotics. In plants, chemical defense seems to be a major reason for P450 diversification. In prokaryotes, P450s are soluble proteins. In eukaryotes, they are usually bound to the endoplasmic reticulum or inner mitochondrial membranes. The electron carrier proteins used for conveying reducing equivalents from NAD(P)H differ with subcellular localization. P450 enzymes catalyze many reactions that are important in drug metabolism or that have practical applications in industry; their economic impact is therefore considerable.