Epigenetic mechanism underlying the development of polycystic ovary syndrome (PCOS)-like phenotypes in prenatally androgenized rhesus monkeys

The pathogenesis of polycystic ovary syndrome (PCOS) is poorly understood. PCOS-like phenotypes are produced by prenatal androgenization (PA) of female rhesus monkeys. We hypothesize that perturbation of the epigenome, through altered DNA methylation, is one of the mechanisms whereby PA reprograms monkeys to develop PCOS. Infant and adult visceral adipose tissues (VAT) harvested from 15 PA and 10 control monkeys were studied. Bisulfite treated samples were subjected to genome-wide CpG methylation analysis, designed to simultaneously measure methylation levels at 27,578 CpG sites. Analysis was carried out using Bayesian Classification with Singular Value Decomposition (BCSVD), testing all probes simultaneously in a single test. Stringent criteria were then applied to filter out invalid probes due to sequence dissimilarities between human probes and monkey DNA, and then mapped to the rhesus genome. This yielded differentially methylated loci between PA and control monkeys, 163 in infant VAT, and 325 in adult VAT (BCSVD P<0.05). Among these two sets of genes, we identified several significant pathways, including the antiproliferative role of TOB in T cell signaling and transforming growth factor-β (TGF-β) signaling. Our results suggest PA may modify DNA methylation patterns in both infant and adult VAT. This pilot study suggests that excess fetal androgen exposure in female nonhuman primates may predispose to PCOS via alteration of the epigenome, providing a novel avenue to understand PCOS in humans.

Congenital adrenal hyperplasia and P450 oxidoreductase deficiency

Congenital adrenal hyperplasia (CAH) comprises a group of autosomal recessive disorders, which are usually due to inactivating mutations in single enzymes involved in adrenal steroid biosynthesis. The characteristics of the biochemical and clinical phenotype depend on the specific enzymatic defect. In 21-hydroxylase and 11beta-hydroxylase deficiency only adrenal steroidogenesis is affected, whereas a defect in 3beta-hydroxysteroid dehydrogenase or 17alpha-hydroxylase also involves gonadal steroid biosynthesis. Recently, mutations in the electron donor enzyme P450 oxidoreductase were identified as the cause of CAH with apparent combined 17alpha-hydroxylase and 21-hydroxylase deficiency, thereby illustrating the impact of redox regulation enzymes on steroidogenesis. P450 oxidoreductase deficiency (ORD) has a complex phenotype including two unique features not observed in any other CAH variant, skeletal malformations and severe genital ambiguity in both sexes. Despite invariably low circulating androgens, females with ORD may present with virilized genitalia and mothers may suffer from virilization during pregnancy. This apparently contradictory finding may be explained by the existence of an alternative pathway in human androgen biosynthesis, with important implications for physiology and pathophysiology. This review discusses the biochemical and clinical presentation and the genetic and functional basis of the currently known CAH variants, with a specific focus on ORD.

Disordered follicle development in ovaries of prenatally androgenized ewes

Exposure to excess androgens in utero induces irreversible changes in gonadotrophin secretion and results in disrupted reproductive endocrine and ovarian function in adulthood, in a manner reminiscent of the common clinical endocrinopathy of polycystic ovary syndrome (PCOS). We have recently identified an abnormality in early follicle development in PCOS which we suggested might be an androgenic effect. We propose that altered ovarian function in androgenized ewes is due to prenatal androgens not only causing an abnormality of gonadotrophin secretion, but also exerting a direct effect on the early stages of folliculogenesis. Therefore, in this study, we explored the possible differences between small preantral follicles in the ovarian cortex of androgenized female lambs with those of normal lambs. At 8 months of age, small ovarian cortical biopsies (approximately 5 mm3) were obtained at laparotomy from nine female lambs that had been exposed to androgens in utero from embryonic days 30 to 90 of a 147-day pregnancy, and 11 control female lambs. Further, ovarian tissue was obtained at 20 months of age from ten androgenized and nine control animals. Tissue was either fixed immediately for histology or cultured for up to 15 days prior to fixing. The number of follicles in haematoxylin and eosin-stained sections was counted and recorded along with the stage of development. Before culture, the total follicle density (follicles/mm3 tissue) was not statistically significantly different between the two types of ovary at either 8 or 20 months of age. Furthermore, there were no statistically significant differences in the density of follicles at each stage of development. However, there was a lower percentage of primordial follicles, but a higher percentage of primary follicles, in biopsies taken at 8 months from androgenized lambs when compared with controls. At 20 months, the proportions of follicles at the primordial and primary stages were not significantly different between the two groups, but this was mainly attributable to an increase in the proportion of growing follicles in biopsies from control animals. Culture of ovarian cortex from 8-month-old lambs resulted in a progressive increase in the proportion of growing follicles when compared with tissue fixed on the day of surgery. However, there was no difference between androgenized and control tissue in the percentage of growing follicles. The increase in the proportion of growing follicles in the cortex of androgenized animals is reminiscent of similar observations in human polycystic ovaries and suggests that excess exposure to androgen in early life plays a part in the accelerated progression of follicle development from the primordial to the primary stage in polycystic ovaries.

Adrenocortical carcinoma in children: clinical aspects and prognosis

Although adrenocortical carcinoma is seen infrequently in children in most countries, it is occurs with significant frequency in Southern Brazil. This has enabled a study of the pattern of this disease in the pediatric age group. Of 78 patients with adrenocortical carcinoma seen at two hospitals in Curitiba, Brazil, 55 were adequately documented, with minimum of 2 years' follow-up, and formed the basis of this paper. Ninety-five percent of the patients showed some degree of virilization, notably pubic and/or body hair, clitoris or penis enlargement, and adult voice. Cushing's syndrome was present in 73% of these cases. The prognosis is age related and is dependent on the resectability of the tumor. Whereas 82% of the children under the age of 2 years survived, the figure for those over the age of 2 years was only 29%. When total resection of the tumor was possible, the survival rate was 67%, with no survival when only partial excision was performed.

Sexual differentiation of pheromone processing: links to male-typical mating behavior and partner preference

Phoenix et al. (Phoenix, C., Goy, R., Gerall, A., Young, W., 1959. Organizing actions of prenatally administered testosterone propionate on the tissues mediating mating behavior in the female guinea pig. Endocrinology 65, 369-382.) were the first to propose an essential role of fetal testosterone exposure in the sexual differentiation of the capacity of mammals to display male-typical mating behavior. In one experiment control male and female guinea pigs as well as females given fetal testosterone actually showed equivalent levels of mounting behavior when gonadectomized and given ovarian steroids prior to adult tests with a stimulus female. This finding is discussed in the context of a recent, high-profile paper by Kimchi et al. (Kimchi, T., Xu, J., Dulac, C., 2007. A functional circuit underlying male sexual behaviour in the female mouse brain. Nature 448, 1009-1014.) arguing that female rodents possess the circuits that control the expression of male-typical mating behavior and that their function is normally suppressed in this sex by pheromonal inputs that are processed via the vomeronasal organ (VNO)-accessory olfactory nervous system. In another Phoenix et al. experiment, significantly more mounting behavior was observed in male guinea pigs and in females given fetal testosterone than in control females following adult gonadectomy and treatment with testosterone. Literature is reviewed that attempts to link sex differences in the anatomy and function of the accessory versus the main olfactory projections to the amygdala and hypothalamus to parallel sex differences in courtship behaviors, including sex partner preference, as well as the capacity to display mounting behavior.

Differential maternal-fetal response to androgenizing luteoma or hyperreactio luteinalis

Lacl of masculinization in female infants whose virilized mothers have h. luteinalis is in contrast to the common finding of fetal masculinization when maternal virilization occurs with luteoma of pregnancy. From the data at hand, this variation in fetal response cannot be explained by differences in the quantity of androgen production nor by the stage of pregnancy when maternal virilization becomes evident. Steroid analysis from cases of h. luteinalis suggests that the placenta may serve as an androgen barrier by aromatizing steroids before they reach the fetus. Testosterone conversion by the placenta of an anencephalic fetus confirms that conversion to estrogens occurs even without significant fetal adrenal activity. Understanding of the breakdown of this mechanism, with resultant fetal masculinization, will require careful evaluation of the steroid milieu in conditions like luteoma in which fetal masculinization often occurs. Both cystic and solid ovarian hyperplasia are recognized as are complications of pregnancy which require proper identification and conservative management. The significant difference in patients at risk for luteoma and h. luteinalis and the pathological and hormonal differences clearly indicate that these are distinct and separate entities.

IN VITRO PRODUCTION OF ANDROGENS BY A VIRILIZING ADRENAL ADENOMA AND ASSOCIATED POLYCYSTIC OVARIES

A case of a virilizing adrenal adenoma in which bilateral Stein-Leventhal ovaries were found is presented. Despite the morphologic similarity, these ovaries did not possess the in vitro potential for increased androgen production demonstrated by polycystic ovaries removed from patients without apparent adrenal disease. These findings lend support to the thesis that, regardless of the organ source, increased androgen production leads to abnormal ovarian function reflected morphologically in follicle maturation arrest.

Gender role behaviour in prenatally dexamethasone-treated children at risk for congenital adrenal hyperplasia--a pilot study

AIM

To investigate the effects of prenatal dexamethasone (DEX) exposure on gender role behaviour.

METHODS

The participants were 25 of the 40 children (62%, mean age 11 years) at risk for CAH treated with DEX prenatally during the years 1985-1995 in Sweden. The control group consisted of 35 sex- and age-matched healthy children. A new inventory, the Karolinska Inventory of Gender Role Behaviour (KI-GRB), was developed to assess directly school-age children's behaviour, and was evaluated using a separate sample of 160 school-age children.

RESULTS

DEX-treated CAH-unaffected boys showed more neutral behaviours than the controls (p = 0.04), while the DEX-treated CAH-unaffected girls did not differ from the controls after adjusting for the site of residence. There was a larger variation in the behaviour of the DEX-treated boys (p < 0.05) and a tendency for less-masculine behaviours in the DEX-treated CAH-unaffected children (p = 0.13). There were no between-group differences in the feminine behaviours. Recalculation of the analyses including the CAH-affected children showed analogous results.

CONCLUSIONS

This pilot study indicates that the gender role behaviour may be affected in boys as an effect of DEX exposure in early pregnancy. Larger retrospective studies are needed for more conclusive results.