The Launch of A Girl's First Period Study: Demystifying Reproductive Hormone Profiles in Adolescent Girls

Limited data exist on the reproductive hormone dynamics that govern the transition from menarche to the establishment of the mature ovulatory cycles of a fertile young woman. It is also unclear how environmental and lifestyle factors could modulate this transition in contemporary girls. Here, we introduce A Girl's First Period Study, an ambitious longitudinal study aimed at charting the early post-menarchal course of a cohort of healthy girls in the Triangle region of North Carolina.

Longitudinal Investigation of Pubertal Milestones and Hormones as a Function of Body Fat in Girls

CONTEXT

Epidemiologic studies have demonstrated that overweight/obese girls (OW/OB) undergo thelarche and menarche earlier than normal weight girls (NW). There have been no longitudinal studies to specifically investigate how body weight/fat affects both clinical and biochemical pubertal markers in girls.

OBJECTIVE

To investigate the effect of total body fat on reproductive hormones and on the maturation of estrogen-sensitive tissues during puberty in girls.

METHODS

Ninety girls (36 OW/OB, 54 NW), aged 8.2 to 14.7 years, completed 2.8 ± 1.7 study visits over 4 years. Visits included dual-energy x-ray absorptiometry to calculate total body fat (TBF), Tanner staging, breast ultrasound for morphological staging (BMORPH; A-E), pelvic ultrasound, hormone tests, and assessment of menarchal status. The effect of TBF on pubertal markers was determined using a mixed, multistate, or Cox proportional hazards model, controlling for baseline BMORPH.

RESULTS

NW were older than OW/OB (11.3 vs 10.2 years, P < .01) at baseline and had more advanced BMORPH (P < .01). Luteinizing hormone, estradiol, and ovarian and uterine volumes increased with time with no effect of TBF. There was a time × TBF interaction for follicle-stimulating hormone, inhibin B, estrone, total and free testosterone, and androstenedione: Levels were initially similar, but after 1 year, levels increased in girls with higher TBF, plateaued in girls with midrange TBF, and decreased in girls with lower TBF. Girls with higher TBF progressed through BMORPH stage D more slowly but achieved menarche earlier than girls with lower TBF.

CONCLUSION

In late puberty, girls with higher TBF demonstrate differences in standard hormonal and clinical markers of puberty. Investigation of the underlying causes and clinical consequences of these differences in girls with higher TBF deserves further study.

Sleep and Puberty

In the 1970's, Boyar and colleagues made the seminal observation that during the early stages of puberty, there is a sleep-specific augmentation of pulsatile luteinizing hormone (LH) secretion. Building on this tantalizing association between sleep and the re-awakening of the neuro-reproductive axis, a number of investigators have since mapped the dynamic relationship between sleep and reproductive hormones across the pubertal transition. In this review, we focus on the complex, reciprocal relationship between sleep and reproductive hormones during adolescence as well as the potential effects of melatonin and orexin on gonadotropin-releasing hormone (GnRH) activity in children with chronic insomnia and narcolepsy, respectively. Given the important interaction between the reproductive and somatotropic axes during puberty, we end with a discussion of sleep and growth hormone (GH) secretion in children.

Mice lacking membrane estrogen receptor 1 are protected from reproductive pathologies resulting from developmental estrogen exposure†

Both membrane and nuclear fractions of estrogen receptor 1 (ESR1) mediate 17β-estradiol (E2) actions. Mice expressing nuclear (n)ESR1 but lacking membrane (m)ESR1 (nuclear-only estrogen receptor 1 [NOER] mice) show reduced E2 responsivity and reproductive abnormalities culminating in adult male and female infertility. Using this model, we investigated whether reproductive pathologies caused by the synthetic estrogen diethylstilbestrol (DES) are mitigated by mESR1 ablation. Homozygous and heterozygous wild-type (WT and HET, respectively) and NOER male and female mice were subcutaneously injected with DES (1 mg/kg body weight [BW]) or vehicle daily from postnatal day (PND) 1-5. Uterine histology was assessed in select DES-treated females at PND 5, whereas others were ovariectomized at PND 60 and treated with E2 (10 μg/kg BW) or vehicle 2 weeks later. Neonatal DES exposure resulted in ovary-independent epithelial proliferation in the vagina and uterus of WT but not NOER females. Neonatal DES treatment also induced ovary-independent adult expression of classical E2-induced transcripts (e.g., lactoferrin [Ltf] and enhancer of zeste homolog 2 [Ezh2]) in WT but not NOER mice. At PND 90, DES-treated WT and HET males showed smaller testes and a high incidence of bacterial pyogranulomatous inflammation encompassing the testes, epididymis and occasionally the ductus deferens with spread to lumbar lymph nodes; such changes were largely absent in NOER males. Results indicate that male and female NOER mice are protected from deleterious effects of neonatal DES, and thus mESR1 signaling is required for adult manifestation of DES-induced reproductive pathologies in both sexes.

SAT-029 AMH Is Higher Across the Menstrual Cycle in Early Post-Menarchal Girls Than in Ovulatory Women

Ovaries of young girls contain healthy and degenerating follicles from the primordial to antral stage, suggesting coordination of growth and atresia. At age 6 yrs, antral follicle (AF) number and size increase; by late puberty, AF count is higher than at any other life stage. The discovery of AMH, a biomarker of AFs, has facilitated the study of the immature ovary. AMH, a granulosa cell product of pre-antral and small AFs, inhibits primordial follicle growth and AF selection. As a marker of AF count, AMH should be highest during puberty, yet cross-sectional studies suggest that AMH peaks in the mid-20’s. In the current studies we compared AMH levels in early post-menarchal girls and regularly cycling adults. The rich phenotypic data available for this adolescent cohort (Sun 2019) was used to investigate further the relationship between AMH, LH, FSH, and sex steroids, and the propensity for anovulatory cycles (ANOV) in girls. 23 healthy girls (12.8–17.6 yrs;1.7±0.2 yrs post-menarche; 56% overweight/obese [OB]) underwent hormone measurements and pelvic ultrasounds during 2 consecutive menstrual cycles. Cycles were classified as ovulatory (OV) based on an LH and E2 peak and P4 &gt;1.65 ng/mL (Sun 2019). AMH was measured in a random subset of samples (5x/subject) with the Ansh ultrasensitive ELISA. Maximum average ovarian volume (VOL) was calculated in the absence of a dominant follicle. Hormones were compared with data from 32 historic adult controls (18–34 yrs; 44% OB) with regular cycles (Lambert-Messerlian 2016). In adults, AMH was measured during the follicular and luteal phase of an OV (5x/subject) using the Ansh assay. AMH was compared among groups using a mixed model. AMH (in adults), LH (in both) and androgens (in girls) were natural log-transformed (ln) before analysis. 11 girls had 2 OV, 5 girls had 1 OV, and 5 girls had no OV; 2 could not be classified due to loss to follow-up. Girls had higher AMH than women (5.2 ± 0.3 vs. 3.3 ± 0.4 ng/mL; p&lt;0.01) and girls with more OV tended to have lower AMH than those with ANOV (2 OV 4.5 ± 0.2, 1 OV 5.7 ± 1.1, 0 OV 6.8 ± 1.1 ng/mL; p=0.1). In girls, AMH correlated with ln_LH (r=0.4, p=0.02), ln_a’dione (r=0.4, p=0.04), ln_testosterone (r=0.5, p=0.02) and VOL (r=0.6, p=0.01) but not with FSH, E2, or BMI. In women, AMH correlated with E2 (r=-0.4, p=0.03) and not with ln_LH or BMI. Within-person variability in AMH was similar in girls and adults (CV 18%). During the early post-menarchal years, AMH levels exceed those of adults with OV, particularly among girls with ANOV, and correlate with LH and androgens. The finding of higher AMH in adolescents is consistent with previous studies demonstrating a peak in AF count during this stage of development. Investigation into how the normal ovary matures and is pruned of excess AFs, either by increased recruitment and growth or by atresia, may provide insights into the pathogenesis of PCOS, wherein follicles are arrested at the pre-antral and antral stage.

AMH is Higher Across the Menstrual Cycle in Early Postmenarchal Girls than in Ovulatory Women

CONTEXT

Adolescents have more small, growing follicles and larger ovaries than normal women and are prone to anovulatory cycles (ANOV). It is unknown if a higher antral follicle count (AFC) per se contributes to ANOV in early postmenarchal girls.

OBJECTIVE

To determine the relationship between AMH (an AFC biomarker), other reproductive hormones, and ANOV in postmenarchal girls and to compare AMH in girls and regularly cycling adults.

METHODS

A total of 23 girls (1.7 ± 0.2 years postmenarche) and 32 historic adult controls (≤34 years) underwent serial hormone measurements during 1 to 2 menstrual cycles. Girls also had pelvic ultrasounds. AMH was measured 5 times/subject using the Ansh ultrasensitive ELISA.

RESULTS

Girls had higher AMH than women (5.2 ± 0.3 vs. 3.3 ± 0.4 ng/mL; P < 0.01) and girls with more ovulatory (OV) cycles tended to have lower AMH than those with ANOV (2 OV 4.5 ± 0.2, 1 OV 5.7 ± 1.1, 0 OV 6.8 ± 1.1 ng/mL; P = 0.1). In girls, AMH correlated with natural-log (ln) transformed LH (r = 0.5, P = 0.01), ln_androstenedione (r = 0.6, P = 0.003), ln_testosterone (r = 0.5, P = 0.02), and ovarian volume (r = 0.7, P < 0.01) but not with FSH, estradiol, P4, or body mass index. In women, AMH correlated with estradiol and P4 (both r = -0.4, P ≤ 0.03) but not with ln_LH or body mass index.

CONCLUSIONS

In postmenarchal girls, AMH is higher than in ovulatory women and is associated with LH, androgens, and a propensity for anovulatory cycles. The cause of the transient increase in AMH and AFC during late puberty and the steps underlying the transition to a mature ovary deserve further study.

Hypothalamic transcriptome of tame and aggressive silver foxes (Vulpes vulpes) identifies gene expression differences shared across brain regions

The underlying neurological events accompanying dog domestication remain elusive. To reconstruct the domestication process in an experimental setting, silver foxes (Vulpes vulpes) have been deliberately bred for tame vs aggressive behaviors for more than 50 generations at the Institute for Cytology and Genetics in Novosibirsk, Russia. The hypothalamus is an essential part of the hypothalamic-pituitary-adrenal axis and regulates the fight-or-flight response, and thus, we hypothesized that selective breeding for tameness/aggressiveness has shaped the hypothalamic transcriptomic profile. RNA-seq analysis identified 70 differentially expressed genes (DEGs). Seven of these genes, DKKL1, FBLN7, NPL, PRIMPOL, PTGRN, SHCBP1L and SKIV2L, showed the same direction expression differences in the hypothalamus, basal forebrain and prefrontal cortex. The genes differentially expressed across the three tissues are involved in cell division, differentiation, adhesion and carbohydrate processing, suggesting an association of these processes with selective breeding. Additionally, 159 transcripts from the hypothalamus demonstrated differences in the abundance of alternative spliced forms between the tame and aggressive foxes. Weighted gene coexpression network analyses also suggested that gene modules in hypothalamus were significantly associated with tame vs aggressive behavior. Pathways associated with these modules include signal transduction, interleukin signaling, cytokine-cytokine receptor interaction and peptide ligand-binding receptors (eg, G-protein coupled receptor [GPCR] ligand binding). Current studies show the selection for tameness vs aggressiveness in foxes is associated with unique hypothalamic gene profiles partly shared with other brain regions and highlight DEGs involved in biological processes such as development, differentiation and immunological responses. The role of these processes in fox and dog domestication remains to be determined.

Multigenerational effects of bisphenol A or ethinyl estradiol exposure on F2 California mice (Peromyscus californicus) pup vocalizations

Rodent pups use vocalizations to communicate with one or both parents in biparental species, such as California mice (Peromyscus californicus). Previous studies have shown California mice developmentally exposed to endocrine disrupting chemicals, bisphenol A (BPA) or ethinyl estradiol (EE), demonstrate later compromised parental behaviors. Reductions in F1 parental behaviors might also be due to decreased emissions of F2 pup vocalizations. Thus, vocalizations of F2 male and female California mice pups born to F1 parents developmentally exposed to BPA, EE, or controls were examined. Postnatal days (PND) 2-4 were considered early postnatal period, PND 7 and 14 were defined as mid-postnatal period, and PND 21 and 28 were classified as late postnatal period. EE pups showed increased latency to emit the first syllable compared to controls. BPA female pups had decreased syllable duration compared to control and EE female pups during the early postnatal period but enhanced responses compared to controls at late postnatal period; whereas, male BPA and EE pups showed greater syllable duration compared to controls during early postnatal period. In mid-postnatal period, F2 BPA and EE pups emitted greater number of phrases than F2 control pups. Results indicate aspects of vocalizations were disrupted in F2 pups born to F1 parents developmentally exposed to BPA or EE, but their responses were not always identical, suggesting BPA might not activate estrogen receptors to the same extent as EE. Changes in vocalization patterns by F2 pups may be due to multigenerational exposure to BPA or EE and/or reduced parental care received.

Karyotype analysis and sex determination in Australian Brush-turkeys (Alectura lathami)

Sexual differentiation across taxa may be due to genetic sex determination (GSD) and/or temperature sex determination (TSD). In many mammals, males are heterogametic (XY); whereas females are homogametic (XX). In most birds, the opposite is the case with females being heterogametic (ZW) and males the homogametic sex (ZZ). Many reptile species lack sex chromosomes, and instead, sexual differentiation is influenced by temperature with specific temperatures promoting males or females varying across species possessing this form of sexual differentiation, although TSD has recently been shown to override GSD in Australian central beaded dragons (Pogona vitticeps). There has been speculation that Australian Brush-turkeys (Alectura lathami) exhibit TSD alone and/or in combination with GSD. Thus, we sought to determine if this species possesses sex chromosomes. Blood was collected from one sexually mature female and two sexually mature males residing at Sylvan Heights Bird Park (SHBP) and shipped for karyotype analysis. Karyotype analysis revealed that contrary to speculation, Australian Brush-turkeys possess the classic avian ZW/ZZ sex chromosomes. It remains a possibility that a biased primary sex ratio of Australian Brush-turkeys might be influenced by maternal condition prior to ovulation that result in her laying predominantly Z- or W-bearing eggs and/or sex-biased mortality due to higher sensitivity of one sex in environmental conditions. A better understanding of how maternal and extrinsic factors might differentially modulate ovulation of Z- or W-bearing eggs and hatching of developing chicks possessing ZW or ZZ sex chromosomes could be essential in conservation strategies used to save endangered members of Megapodiidae.

Toxicological effects of pet food ingredients on canine bone marrow-derived mesenchymal stem cells and enterocyte-like cells

We developed an in vitro method to assess pet food ingredients safety. Canine bone marrow-derived mesenchymal stem cells (BMSC) were differentiated into enterocyte-like cells (ELC) to assess toxicity in cells representing similar patterns of exposure in vivo. The toxicological profile of clove leave oil, eugenol, guanosine monophosphate (GMP), GMP + inosine monophosphate, sorbose, ginger root extract, cinnamon bark oil, cinnamaldehyde, thyme oil, thymol and citric acid was assessed in BMSC and ELC. The LC50 for GMP + inosine monophosphate was 59.42 ± 0.90 and 56.7 ± 3.5 mg ml(-1) for BMSC and ELC; 56.84 ± 0.95 and 53.66 ± 1.36 mg ml(-1) for GMP; 0.02 ± 0.001 and 1.25 ± 0.47 mg ml(-1) for citric acid; 0.077 ± 0.002 and 0.037 ± 0.01 mg ml(-1) for cinnamaldehyde; 0.002 ± 0.0001 and 0.002 ± 0.0008 mg ml(-1) for thymol; 0.080 ± 0.003 and 0.059 ± 0.001 mg ml(-1) for thyme oil; 0.111 ± 0.002 and 0.054 ± 0.01 mg ml(-1) for cinnamon bark oil; 0.119 ± 0.0004 and 0.099 ± 0.011 mg ml(-1) for clove leave oil; 0.04 ± 0.001 and 0.028 ± 0.002 mg ml(-1) for eugenol; 2.80 ± 0.11 and 1.75 ± 0.51 mg ml(-1) for ginger root extract; > 200 and 116.78 ± 7.35 mg ml(-1) for sorbose. Lemon grass oil was evaluated at 0.003-0.9 in BMSC and .03-0.9 mg ml(-1) in ELC and its mechanistic effect was investigated. The gene toxicology studies showed regulation of 61% genes in CYP450 pathway, 37% in cholestasis and 33% in immunotoxicity pathways for BMSC. For ELC, 80% for heat shock response, 69% for beta-oxidation and 65% for mitochondrial energy metabolism. In conclusion, these studies provide a baseline against which differential toxicity of dietary feed ingredients can be assessed in vitro for direct effects on canine cells and demonstrate differential toxicity in differentiated cells that represent gastrointestinal epithelial cells.

Vaccine effectiveness in preventing laboratory-confirmed influenza in Navarre, Spain: 2013/14 mid-season analysis

We estimate mid-2013/14 season vaccine effectiveness (VE) of the influenza trivalent vaccine in Navarre, Spain. Influenza-like illness cases attended in hospital (n=431) and primary healthcare (n=344) were included. The overall adjusted VE in preventing laboratory-confirmed influenza was 24% (95% CI: -14 to 50). The VE was 40% (95% CI: -12 to 68) against influenza A(H1)pdm09 and 13% (95% CI: -36 to 45) against influenza A(H3). These results suggest a moderate preventive effect against influenza A(H1)pdm09 and low protection against influenza A(H3).