Hormonal mechanisms in the onset of puberty

The relationship between timing of onset of menarche and depressive symptoms from adolescence to adulthood

AIMS

Girls who experience an earlier onset of menarche than their peers are at increased risk of depressive symptoms in mid-adolescence, but it is unclear if this association persists into adulthood. This study examines whether longitudinal patterns of depressive symptoms from adolescence to adulthood vary according to timing of menarche.

METHODS

About 4,864 female participants in the UK Avon Longitudinal Study of Parents and Children provided data on age at onset of menarche (assessed in repeated questionnaires from 8 to 17 years) and depressive symptoms across nine time points (13 to 26 years) using the Short Mood and Feelings Questionnaire. We compared patterns of depressive symptoms in girls with 'early' (<11.5 years), 'normative' (11.5 to 13.5 years) and 'late' (≥13.5 years) menarche using a linear spline multilevel growth curve model adjusted for indicators of socioeconomic position, father absence and body mass index.

RESULTS

Early, compared with normative, menarche was associated with higher levels of depressive symptoms at age 14 (imputed adjusted estimated difference = 0.94, 95% confidence interval [CI] = 0.44, 1.45), but the association attenuated at 24 years (0.24 [-0.72, 1.19]). Late menarche, compared with normative, was associated with a lower level of depressive symptoms at age 14 (-0.69 [-1.10, -0.29]), but this association also attenuated at 24 years (-0.15 [-0.92, 0.62]).

CONCLUSIONS

This study did not find a persistent effect of early menarche, compared to normative, on depressive symptoms. However, our findings are consistent with the level of depressive symptoms increasing at the onset of menarche irrespective of timing. The late onset girls 'catch up' with their peers who experience menarche earlier in terms of depressive symptoms. Future studies should continue to assess the impact of timing of menarche further into adulthood.

Acquisition and establishment of the oral microbiota

Acquisition and establishment of the oral microbiota occur in a dynamic process over various stages and involve close and continuous interactions with the host and its environment. In the present review, we discuss the stages of this process in chronological order. We start with the prenatal period and address the following questions: ‘Is the fetus exposed to maternal microbiota during pregnancy?’ and ‘If so, what is the potential role of this exposure?’ We comment on recent reports of finding bacterial DNA in placenta during pregnancies, and provide current views on the potential functions of prenatal microbial encounters. Next, we discuss the physiological adaptations that take place in the newborn during the birth process and the effect of this phase of life on the acquisition of the oral microbiota. Is it really just exposure to maternal vaginal microbes that results in the difference between vaginally and Cesarian section‐born infants? Then, we review the postnatal phase, in which we focus on transmission of microbes, the intraoral niche specificity, the effects of the host behavior and environment, as well as the role of genetic background of the host on shaping the oral microbial ecosystem. We discuss the changes in oral microbiota during the transition from deciduous to permanent dentition and during puberty. We also address the finite knowledge on colonization of the oral cavity by microbes other than the bacterial component. Finally, we identify the main outstanding questions that limit our understanding of the acquisition and establishment of a healthy microbiome at an individual level.

Prospects of nutritional interventions in the care of COVID-19 patients

The novel coronavirus disease 2019 (COVID-19) has unfolded an unprecedented worldwide public health emergency with disastrous economic consequences. Around 96 million coronavirus cases have already been identified with over half a million deaths. Despite numerous efforts by the government as well as international organizations, these numbers are still increasing with a surprising rate. Although urgent and absolutely necessary, a reliable therapeutic or vaccine is still elusive and this status quo may remain for an uncertain period of time. Taken that into account, boosting up adaptive immunity through nutritional interventions may help subside this epidemic and save many lives. This review focuses on the nexus between a balanced diet and adaptive immunity, particularly, how a poor diet may lead to compromised immunity resulting in susceptibility to viral infections. Additionally, we discuss how nutrients (vitamins, minerals, trace elements) can be used as a tool to modulate immune response and thus impede viral infections. The study also summarizes nutritional recommendations to combat COVID-19 in different countries and territories as well as dietary sources of those key nutrients. Moreover, different nutritional intervention strategies based on different age groups, physiological and medical conditions were also included, and the challenges of nutritional interventions towards the care of COVID-19 patients are also discussed. Since the availability of a drug or vaccine is still uncertain, a balanced diet or nutrient therapy can be used as a robust strategy to combat COVID-19. Thus, we hope this review may help to make an informed decision with regard to diet choice both at individual level as well as clinical settings.

Hormone References for Ultrasound Breast Staging and Endocrine Profiling to Detect Female Onset of Puberty

CONTEXT

Application of ultrasound (US) to evaluate attainment and morphology of glandular tissue provides a new rationale for evaluating onset and progression of female puberty, but currently no hormone references complement this method. Furthermore, previous studies have not explored the predictive value of endocrine profiling to determine female puberty onset.

OBJECTIVE

To integrate US breast staging with hypothalamic-pituitary-gonadal hormone references and test the predictive value of an endocrine profile to determine thelarche.

DESIGN SETTING AND PARTICIPANTS

Cross-sectional sample of 601 healthy Norwegian girls, ages 6 to 16 years.

MAIN OUTCOME MEASURES

Clinical and ultrasound breast evaluations were performed for all included girls. Blood samples were analyzed by immunoassay and ultrasensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify estradiol (E2) and estrone (E1) from the subpicomolar range.

RESULTS

References for E2, E1, luteinizing hormone, follicle-stimulating hormone, and sex hormone-binding globulin were constructed in relation to chronological age, Tanner stages, and US breast stages. An endocrine profile index score derived from principal component analysis of these analytes was a better marker of puberty onset than age or any individual hormone, with receiver-operating characteristic area under the curve 0.91 (P < 0.001). Ultrasound detection of nonpalpable glandular tissue in 14 out of 264 (5.3%) girls with clinically prepubertal presentation was associated with significantly higher median serum levels of E2 (12.5 vs 4.9 pmol/L; P < 0.05) and a distinct endocrine profile (arbitrary units; P < 0.001).

CONCLUSIONS

We provide the first hormone references for use with US breast staging and demonstrate the application of endocrine profiling to improve detection of female puberty onset.

Multiple Points Change in the Association of Blood Pressure Subtypes with Anthropometric Indices of Adiposity among Children in a Rural Population

BACKGROUND

Hypertension has gained global significance and risk of cardiovascular disease, and adiposity is the most important of the conditions associated with and considered responsible for hypertension in children. Therefore, the present study aimed to determine whether indices of adiposity independently predicted blood pressure at multiple points in gender-specific groups.

METHODS

This was a cross-sectional study involving 10 randomly selected primary schools within the Ellisras Longitudinal Study, and involved 1816 adolescents (876 girls and 940 boys) aged 8 to 17 years. All the anthropometric indices and blood pressures (BP) were examined according to the International Society for the Advancement of Kinanthropometry protocol.

RESULTS

In an adjusted linear quantile regression analysis of boys, waist circumference (WC) was associated with BP across all multiple points of systolic blood pressure (SBP). Furthermore, the triceps skinfold site was associated with high SBP. In girls, body mass index (BMI) was significantly associated with SBP after adjustment for potential confounders. Other anthropometric indices of adiposity, including WC, biceps, and triceps skinfold sites were not associated with SBP.

CONCLUSIONS

The results of the present study suggest that in black South African children, variables such as WC and triceps skinfold site may provide stronger explanatory capacity to SBP variance and systolic hypertension risk in boys than other adiposity indices; whereas in girls, only WC and BMI predict diastolic blood pressure (DBP) and SBP, respectively.

Gut permeability is affected by sex and increased in children with irritable bowel syndrome but not in functional abdominal pain

BACKGROUND

Gut permeability is increased in some children and adults with irritable bowel syndrome (IBS). We investigated whether this also is true for children with functional abdominal pain (FAP). We also determined whether sex affected permeability results.

METHODS

Sucrose, lactulose, mannitol, and sucralose were ingested after an overnight fast in well-phenotyped children with IBS (n = 95), FAP (n = 25), and healthy controls (HC) (n = 60). Urine was collected for 24 hours. Percent sucrose recovery was calculated based on the 0- to 3-hour collection; lactulose/mannitol ratio both on the 0- to 3-hour and 0- to 24-hour collections; and percent sucralose recovery on the 0- to 24-hours collection.

KEY RESULTS

Age was similar among the groups (P = .26). The lactulose/mannitol ratio was increased in IBS compared with HC at 0-3 and 0-24 hours (P = .023, P = .05, respectively). Percent sucralose recovery was greater in FAP than in HC (P = .045). No differences were noted among the groups in percent sucrose recovery. Taking sex into account, percent sucrose recovery was greater in girls with IBS vs HC girls (P = .008). The lactulose/mannitol ratio was greater in boys with IBS compared with HC boys at both time points (both P = .02). Percent sucralose recovery was greater in boys with IBS than in FAP or HC (both P < .001).

CONCLUSIONS AND INFERENCES

Sex is a critically important factor when measuring gut permeability. Boys with IBS have increased lactulose/mannitol ratios and percent sucralose recovery. Girls with IBS have increased percent recovery of sucrose. Children with FAP do not demonstrate abnormal gut 0permeability even taking sex into account.

Influence of muscle mass on the serum uric acid levels in children and adolescents

BACKGROUND AND AIM

Uric acid (UA) is an end-product of purine catabolism and its increase in blood is a risk factor for several diseases. UA levels in men are usually higher than in women. This difference is partially due to sex hormones. We sought to investigate the onset of sexual difference in UA levels during pubertal development and the determinants of UA levels in children and adolescents.

METHODS AND RESULTS

The muscle mass and fat mass were measured by multi-frequency bioelectrical impedance in a cross-sectional study involving 823 children and adolescents (both sexes; 6-18 years). Serum UA was determined using a commercially available kit. UA levels started to become higher in boys (5.0 ± 1.0 mg/dL) than in girls (4.1 ± 0.9 mg/dL) around 13 years. Boys in the highest quartile of muscle mass presented higher UA levels (5.2 ± 0.7 mg/dL) when compared with the third (4.2 ± 0.7 mg/dL), second (3.7 ± 0.9 mg/dL) and first (3.4 ± 0.9 mg/dL). Similarly, girls in the highest quartile of muscle mass presented higher UA levels (4.2 ± 0.7 mg/dL) when compared with the second (3.8 ± 0.9 mg/dL) and first (3.3 ± 0.9 mg/dL). Muscle mass explained 43.0% and 7.7% of the variability of UA in boys and girls, respectively.

CONCLUSION

Sexual differences in serum UA levels begin at puberty and partially result from a direct influence of muscle mass.

LIN28B affects gene expression at the hypothalamic-pituitary axis and serum testosterone levels

Genome-wide association studies (GWAS) have recurrently associated sequence variation nearby LIN28B with pubertal timing, growth and disease. However, the biology linking LIN28B with these traits is still poorly understood. With our study, we sought to elucidate the mechanisms behind the LIN28B associations, with a special focus on studying LIN28B function at the hypothalamic-pituitary (HP) axis that is ultimately responsible for pubertal onset. Using CRISPR-Cas9 technology, we first generated lin28b knockout (KO) zebrafish. Compared to controls, the lin28b KO fish showed both accelerated growth tempo, reduced adult size and increased expression of mitochondrial genes during larval development. Importantly, data from the knockout zebrafish models and adult humans imply that LIN28B expression has potential to affect gene expression in the HP axis. Specifically, our results suggest that LIN28B expression correlates positively with the expression of ESR1 in the hypothalamus and POMC in the pituitary. Moreover, we show how the pubertal timing advancing allele (T) for rs7759938 at the LIN28B locus associates with higher testosterone levels in the UK Biobank data. Overall, we provide novel evidence that LIN28B contributes to the regulation of sex hormone pathways, which might help explain why the gene associates with several distinct traits.

Pubertal Hormonal Changes and the Autonomic Nervous System: Potential Role in Pediatric Orthostatic Intolerance

Puberty is initiated by hormonal changes in the adolescent body that trigger physical and behavioral changes to reach adult maturation. As these changes occur, some adolescents experience concerning pubertal symptoms that are associated with dysfunction of the autonomic nervous system (ANS). Vasovagal syncope (VVS) and Postural Orthostatic Tachycardia Syndrome (POTS) are common disorders of the ANS associated with puberty that are related to orthostatic intolerance and share similar symptoms. Compared to young males, young females have decreased orthostatic tolerance and a higher incidence of VVS and POTS. As puberty is linked to changes in specific sex and non-sex hormones, and hormonal therapy sometimes improves orthostatic symptoms in female VVS patients, it is possible that pubertal hormones play a role in the increased susceptibility of young females to autonomic dysfunction. The purpose of this paper is to review the key hormonal changes associated with female puberty, their effects on the ANS, and their potential role in predisposing some adolescent females to cardiovascular autonomic dysfunctions such as VVS and POTS. Increases in pubertal hormones such as estrogen, thyroid hormones, growth hormone, insulin, and insulin-like growth factor-1 promote vasodilatation and decrease blood volume. This may be exacerbated by higher levels of progesterone, which suppresses catecholamine secretion and sympathetic outflow. Abnormal heart rate increases in POTS patients may be exacerbated by pubertal increases in leptin, insulin, and thyroid hormones acting to increase sympathetic nervous system activity and/or catecholamine levels. Given the coincidental timing of female pubertal hormone surges and adolescent onset of VVS and POTS in young women, coupled with the known roles of these hormones in modulating cardiovascular homeostasis, it is likely that female pubertal hormones play a role in predisposing females to VVS and POTS during puberty. Further research is necessary to confirm the effects of female pubertal hormones on autonomic function, and their role in pubertal autonomic disorders such as VVS and POTS, in order to inform the treatment and management of these debilitating disorders.

Relationship Between Gender and the Effectiveness of Montelukast: An Italian/Danish Register-Based Retrospective Cohort Study

Rationale: Gender-related differences in asthma prevalence, pathophysiology and clinical features induced by sex steroids have been investigated, however, how gender influences response to asthma treatments in routine clinical practice have not yet been elucidated fully. This aspect is crucial for montelukast considering the jeopardization of asthmatic patients that benefit from this treatment and the existence of evidence of gender differences in leukotriene levels. Therefore, to fulfill this medical need, we investigated the role of gender on a set of montelukast' effectiveness surrogates in adults and pediatric patients with asthma. Methods: The study settings were Napoli 2 Local Health Unit (southern Italy) and the entire Danish territory. The study population was composed of adult and pediatric patients with asthma. Cumulative incidence curves, unadjusted and adjusted Cox regression were used as statistical models to compare aforementioned outcomes between genders. Results: Adult Italian male users of montelukast had a statistically lower persistence in montelukast treatment compared to female users. In the adjusted analyses, they had a higher hazard of montelukast' withdrawal (Hazard Ratio [HR] 1.07; 95% Confidence Interval [CI] 1.01-1.14), add-on/switch to a long-term treatment for asthma following montelukast withdrawal (HR 1.72; 95%CI 1.39-2.12), and rescue therapy with short-acting β2 agonist (HR 1.24; 95%CI 1.04-1.47). In the adult Danish cohort, we also found that male users had higher a hazard of rescue therapy with oral corticosteroids (HR 1.10; 95%CI 1.04-1.16). In the pediatric cohorts, no statistically significant differences were observed between genders for aforementioned outcomes. Conclusions: In adults, male gender was associated with increased hazards of montelukast discontinuation, add-on/switch to a long-term treatment for asthma following montelukast withdrawal, and rescue therapy with oral corticosteroids or short-acting β2 agonist when compared to the female gender. As expected, these associations were reversed or absent in pediatric patients.

Age at menarche, androgen concentrations, and midlife obesity: findings from the Midlife Women's Health Study

OBJECTIVE

Studies have shown that earlier age at menarche is associated with a higher risk of midlife obesity; however, the mechanism underlying this association is not known. The purpose of this study was to examine whether the association between age at menarche and midlife obesity is due to variation in circulating androgen concentrations.

METHODS

Baseline data were analyzed from 748 women aged 45 to 54 years enrolled in the Midlife Women's Health Study, a prospective cohort study conducted in the Baltimore, MD region. Information on age at menarche was collected through a self-administered questionnaire. Body mass index (BMI) was calculated using height and weight measured at a clinic visit. Obesity was defined as a BMI between 30 and 34.9 kg/m; super obesity was defined as a BMI greater than 35 kg/m. Testosterone, estradiol, and sex hormone-binding globulin were measured in blood samples using enzyme-linked immunosorbent assays. The free androgen index (FAI) was calculated using the formula: (testosterone × 3.467)/sex hormone-binding globulin × 100.

RESULTS

After adjustment for covariates, for each year increase in age at menarche, the odds of obesity and super obesity decreased by 31% (odds ratio (OR) 0.69; 95% confidence limits (CL) 0.59, 0.81) and 34% (OR 0.66; 95% CL 0.52, 0.83), respectively. Addition of the FAI into the models did not attenuate the observed estimates.

CONCLUSIONS

The results of this study indicate that age at menarche is associated with midlife obesity independent of free testosterone concentrations measured in adulthood.

Activity Dependent Modulation of Granule Cell Survival in the Accessory Olfactory Bulb at Puberty

The vomeronasal system (VNS) is specialized in the detection of salient chemical cues triggering social and neuroendocrine responses. Such responses are not always stereotyped, instead, they vary depending on age, sex, and reproductive state, yet the mechanisms underlying this variability are unclear. Here, by analyzing neuronal survival in the first processing nucleus of the VNS, namely the accessory olfactory bulb (AOB), through multiple bromodeoxyuridine birthdating protocols, we show that exposure of female mice to male soiled bedding material affects the integration of newborn granule interneurons mainly after puberty. This effect is induced by urine compounds produced by mature males, as bedding soiled by younger males was ineffective. The granule cell increase induced by mature male odor exposure is not prevented by pre-pubertal ovariectomy, indicating a lesser role of circulating estrogens in this plasticity. Interestingly, the intake of adult male urine-derived cues by the female vomeronasal organ increases during puberty, suggesting a direct correlation between sensory activity and AOB neuronal plasticity. Thus, as odor exposure increases the responses of newly born cells to the experienced stimuli, the addition of new GABAergic inhibitory cells to the AOB might contribute to the shaping of vomeronasal processing of male cues after puberty. Consistently, only after puberty, female mice are capable to discriminate individual male odors through the VNS.

Gender differences in oral health in South Asia: metadata imply multifactorial biological and cultural causes

OBJECTS

This study was designed to examine the magnitude and etiology of gender differences in oral health. South Asia was selected for study because sex differences in caries rates exist in prehistory here, great cultural diversity provides context, and clinical reports document caries by gender.

METHODS

A literature survey yielded extensive data on caries rates in India, Nepal, Bangladesh, and Sri Lanka. The percentage of individuals with caries (prevalence) and the mean number of decayed, missing, and filled teeth (experience) comprise the data. Statistical tests for gender differences come from published sources or were independently computed.

RESULTS

Higher caries rates were found more often among females than males. The data show that: (a) in male children caries rates are greater than, or equal to, female rates, (b) the gender bias reverses (F > M caries rates) from adolescence through the reproductive years, (c) mature adults typically exhibit significant differences, with higher caries rates in females, (d) a male gender bias in adults is rare, and (e) though some studies find no significant gender difference in caries, a female bias dominates. Tooth loss is also greater in women than men and often results from caries (vs. periodontal disease).

CONCLUSIONS

The gender gap in oral health exists in South Asia and results from genetic, hormonal, and cultural influences. Three cultural factors contribute to this gender gap South Asia: (a) the relative value of sons and daughters, (b) frequent fasting among Hindu women, and (c) the belief that dietary restrictions result in easier childbirth.

Changes in steroid pattern following acute and chronic adrenocorticotropin administration in premature adrenarche

Biochemically adrenarche is characterized by increased production of 5-ene steroids, in particular Dehydroepiandrosterone (DHA) and its sulphate (DHA-S). It is still not clear if ACTH is responsible for this adrenal steroid production. The aim of the present study was to evaluate the effect of acute and chronic ACTH administration, without dexamethasone pretreatment, on hormonal patterns in 20 patients (5 males aged between 6 8/12 and 7 10/12 years and 15 females aged between 5 9/12 and 7 6/12 years) with idiopathic premature adrenarche. Pregnenolone (5P), DHA, DHA-S, 17-hydroxyprogesterone (17-OHP), androstenedione (A), 11-deoxycortisol (S) and cortisol (F) have been determined by Radioimmunoassay. The results of the hormonal evaluation (means +/- standard error) showed high plasma levels of DHA [329.2 +/- 41.7 ng/100 ml (dl)] and DHA-S (169.1 +/- 54 micrograms/dl) and slightly increased levels of 5P (74.4 +/- 7.1 ng/dl), of A (45.4 +/- 4.6 ng/dl) and 17-OHP (69.3 +/- 11.3 ng/dl) in comparison to those of controls, thus indicating a decrease in 3 beta-hydroxysteroid dehydrogenase activity and an increase in 17-20-lyase and 17-hydroxylase activities, characteristic for adrenarche. Acute and chronic ACTH stimulation did not amplify the characteristic basal hormonal pattern, but they induced a shift of adrenal steroid metabolism to 4-ene pathway, suggesting that the basal hormonal pattern in premature adrenarche may be independent or, at least, not exclusively dependent on ACTH control.

A mixed longitudinal study of adrenal steroid excretion in childhood and the mechanism of adrenarche

Twenty four-hour urine samples have been collected 6 monthly for 18 months from 127 normal boys aged between 7.5 and 17 years. Urinary steroid metabolites have been measured by gas-liquid chromatography and ratios of steroid metabolites used to draw conclusions about likely enzymic activities at each step in the adrenal biosynthetic pathway. DHA excretion rose throughout the study, especially between 7.5 and 11 years. Metabolites of cortisol and corticosterone did not increase when related to surface area. During adrenarche there were changes consistent with a decrease in 3 beta-hydroxysteroid dehydrogenase activity, a slight rise in 17 alpha hydroxylase activity, a marked rise in 17,20 lyase activity, and a fall in 11 beta hydroxylase activity. These data are compatible with the hypothesis that a small reduction in the ability to synthesize cortisol requires a marginal increase in the secretion of ACTH and/or other CRF-induced peptides to maintain cortisol production rate. ACTH itself or a dexamethasone-suppressible CRF-induced peptide would in such a case control the growth of the zona reticularis at adrenarche, which thus appears to be primarily an adrenal event.

Blood-spot 17 alpha-hydroxyprogesterone radioimmunoassay in the follow-up of congenital adrenal hyperplasia

The value of plasma 17 alpha-hydroxyprogesterone (17 alpha-OHP) concentration in monitoring the treatment of congenital adrenal hyperplasia (CAH) was studied by using a capillary blood micromethod. The blood-spot 17-OHP radioimmunoassay method involves serial sampling throughout the day and sending the samples into the centre by mail. Follow-up of seven children treated for CAH due to 21-hydroxylase deficiency showed that a single measurement of plasma 17-OHP concentration cannot be relied upon to determine adequacy of control, since circadian variation and timing of the sample in relation to the last dose of glucocorticoid may influence the plasma level of 17 alpha-OHP. Our data confirm the value of sequential 17 alpha-OHP assays throughout the day in the follow-up of CAH. With the blood-spot method the 17 alpha-OHP determinations can be used on a wide scale for monitoring therapy.

Hormonal regulation of LH stimulation of testosterone production in isolated Leydig cells of immature rats: the effect of hypophysectomy, FSH, and estradiol-17beta

Testosterone production in isolated Leydig cells from testes of immature and adult rats was stimulated by addition of LH in a dose dependent way. Hypophysectomy of adult rats had no influence on LH-stimulated testosterone production in isolated Leydig cells after 5 days. In contrast hypophysectomy of immature rats resulted after 5 days in an almost complete loss of LH sensitivity of isolated Leydig cells. Daily adminitration of FSH during 5 days starting immediately after hypophysectomy maintained LH responsiveness of isolated Leydig cells of immature rats. Also FSH administration starting on day 5 after hypophysectomy resulted in a restoration of LH responsiveness. Estradiol benzoate, injected simultaneously with FSH, abolished the FSH-induced LH responsiveness.

Endocrine aspects of anovulation

Endocrine features of anovulation are reviewed, with particular emphasis on methods of investigation. The value of, and indications for, measurements of serum gonadotrophin concentrations are discussed: it appears that FSH measurements allow better discrimination than LH measurements in diagnosing patients with primary ovarian failure. The results of stimulation tests with the synthetic form of gonadotrophin-releasing hormone are described and the relationship of tests with exogenous progestogens and clomiphene is discussed.