Pubertal Onset Research Articles

ALKBH5 Reduces BMP15 mRNA Stability and Regulates Bovine Puberty Initiation Through an m6A-Dependent Pathway.

The timing of puberty significantly influences subsequent reproductive performance in cattle. N6-methyladenosine (m6A) is a key epigenetic modification involved in the regulation of pubertal onset. However, limited research has investigated alterations in m6A methylation within the hypothalamic-pituitary-ovarian (HPO) axis during the onset of puberty. In this study, combined analysis of methylated RNA immunoprecipitation sequencing (MeRIP-Seq) and RNA sequencing (RNA-seq) is used to describe the overall modification pattern of m6A in the HPO axis, while GSEA, KEGG, and GO analyses are used to describe the enrichment pathways of differentially expressed genes and differentially methylated genes. The m6A modifications of the differential genes KL, IGSF10, PAPPA2, and BMP15 and the pathways of cell adhesion molecules (CAMs), TGF-β, cell cycle, and steroid hormone synthesis may play roles in regulating the function of the HPO axis tissue during pubertal transition. Notably, BMP15's m6A modification depends on the action of the demethylase ALKBH5, which is recognized by the reader protein YTHDF2, promoting bovine granulosa cell proliferation, steroid production, and estrogen secretion. This study reveals for the first time the modification mechanism of BMP15 m6A during the initiation of bovine puberty, which will provide useful information for improving the reproductive efficiency of Chinese beef cattle.

Serum DLK1 During Minipuberty and Pubertal Transition in Healthy Girls and in Girls with Precocious Puberty.

Delta-like non-canonical notch ligand 1 (DLK1) is negatively associated with bodyweight. DLK1 pathogenic variants cause central precocious puberty (CPP) and obesity, suggesting that DLK1 link the well-established association between higher BMI and earlier pubertal onset. However, little is known about the trajectories of circulating DKL1 in healthy girls as well as in girls with precocious puberty. To evaluate longitudinal changes in circulating DLK1 concentrations in 1) full-term, singleton healthy infant girls 2) healthy girls during pubertal transition 3) girls with CPP during treatment with gonadotropin-releasing hormone agonist (GnRHa). Three longitudinal studies of 1) healthy, infant girls (n=85), 2) healthy, peripubertal girls (n=15), 3) girls with CPP before and after GnRHa treatment (n=15).Body fat percentage (BF%) by Slaughter equation. Serum concentrations of DLK1 by ELISA. Serum concentration of DLK1 in healthy infant girls declined significantly through the first year of life (17.6 ng/mL to 9.9 nh/mL, p=0.020). DLK1 was inversely correlated with birth weight and BF%: r=-0.220, p=0.044 and r=-0.503, p<0.001, respectively. DLK1 declined from one year prior to pubertal onset to time of first examination after pubertal onset (10.4 ng/mL to 9.2 n/mL, p=0.004) as well as to time at the last pubertal evaluation (10.4 ng/mL to 9.8 ng/mL, p=0.006). DLK1 levels were not affected by GnRHa treatment. Circulating DLK1 levels declined steeply during infancy and less pronounced through pubertal development. Due to considerable inter-individual variation, DLK1 is not useful as a diagnostic marker of pubertal onset. Importantly, DLK1 was negatively associated with birth weight and body fat percentage.

Age, sex, and cell type-resolved hypothalamic gene expression across the pubertal transition in mice

BackgroundThe hypothalamus plays a central role in regulating puberty. However, our knowledge of the postnatal gene regulatory networks that control the pubertal transition in males and females is incomplete. Here, we investigate the age-, sex- and cell-type-specific gene regulation in the hypothalamus across the pubertal transition.MethodsWe used RNA-seq to profile hypothalamic gene expression in male and female mice at five time points spanning the onset of puberty (postnatal days (PD) 12, 22, 27, 32, and 37). By combining this data with hypothalamic single nuclei RNA-seq data from pre- and postpubertal mice, we assigned gene expression changes to their most likely cell types of origin. In our colony, pubertal onset occurs earlier in male mice, allowing us to focus on genes whose expression is dynamic across ages and offset between sexes, and to explore the bases of sex effects.ResultsOur age-by-sex pattern of expression enriched for biological pathways involved hormone production, neuronal activation, and glial maturation. Additionally, we inferred a robust expansion of oligodendrocytes precursor cells into mature oligodendrocytes spanning the prepubertal (PD12) to peri-pubertal (PD27) timepoints. Using spatial transcriptomic data from postpubertal mice, we observed the lateral hypothalamic area and zona incerta were the most oligodendrocyte-rich regions and that these cells expressed genes known to be involved in pubertal regulation.ConclusionTogether, by incorporating multiple biological timepoints and using sex as a variable, we identified gene and cell-type changes that may participate in orchestrating the pubertal transition and provided a resource for future studies of postnatal hypothalamic gene regulation.

Selective depletion of kisspeptin neurons in the hypothalamic arcuate nucleus in early juvenile life reduces pubertal LH secretion and delays puberty onset in mice.

Puberty is the critical developmental transition to reproductive capability driven by the activation of gonadotropin-releasing hormone (GnRH) neurons. The complex neural mechanisms underlying pubertal activation of GnRH secretion still remain unknown, yet likely include kisspeptin neurons. However, kisspeptin neurons reside in several hypothalamic areas and the specific kisspeptin population timing pubertal onset remains undetermined. To investigate this, we strategically capitalized on the differential ontological expression of the Kiss1 gene in different hypothalamic nuclei to selectively ablate just arcuate kisspeptin neurons (aka KNDy neurons) during the early juvenile period, well before puberty, while sparing RP3V kisspeptin neurons. Both male and female transgenic mice with a majority of their KNDy neurons ablated (KNDyABL) by diphtheria toxin treatment in juvenile life demonstrated significantly delayed puberty onset and lower peripubertal LH secretion than controls. In adulthood, KNDyABL mice demonstrated normal invivo LH pulse frequency with lower basal and peak LH levels, suggesting that only a small subset of KNDy neurons is sufficient for normal GnRH pulse timing but more KNDy cells are needed to secrete normal LH concentrations. Unlike prior KNDy ablation studies in rats, there was no alteration in the occurrence or magnitude of estradiol-induced LH surges in KNDyABL female mice, indicating that a complete KNDy neuronal population is not essential for normal LH surge generation. This study teases apart the contributions of different kisspeptin neural populations to the control of puberty onset, demonstrating that a majority of KNDy neurons in the arcuate nucleus are necessary for the proper timing of puberty in both sexes.

7349 Identifying the Onset of Puberty in Boys Born Small for Gestational Age (SGA)

Abstract Disclosure: S.M. Suco: None. A.C. Keselman: None. M.G. Ballerini: None. M.E. Rodriguez: None. M.G. Ropelato: None. S. Rosenbrock: None. D. Braslavsky: None. R.A. Rey: None. R.P. Grinspon: None. Introduction: Some children born SGA have an earlier pubertal onset and more rapid progression. Therefore, it is essential to identify the onset of puberty to proceed in a timely and appropriate manner. As it has also been suggested that there may be some gonadal dysfunction, the classic markers of pubertal onset, for example, testicular volume ≥ 4ml, may not be appropriate in these cases. Objective: To describe the clinical and biochemical characteristics of pubertal maturation in boys born SGA and determine parameters that best identify pubertal onset. Methods: We perform a retrospective, descriptive study of a cohort of boys born SGA with longitudinal follow-up, at a tertiary pediatric public hospital in Buenos Aires, Argentina. The subjects were selected from 1997 to 2023. Main outcome measures were serum levels of LH and AMH and testicular volume (TV). Additionally, height velocity, bone age, IGF1 and HOMA-IR were also collected to analyze its association with puberty. Pubertal onset was defined as serum LH ≥ 0.3 U/L and/or a decrease in serum AMH ≥ 30%. Results: The cohort included 25 boys born SGA, 24% were born prematurely and 60% were referred for short stature. In 18 boys (72%) AMH decline occurred with testicular volume &amp;lt; 4ml, at a median age of 9.8 yr (IQR 8.3 – 11 yr), and with median TV of 2ml. In 5 boys, LH was ≥ 0.3 U/L when AMH decline &amp;gt;30%. In 14 boys (56%) TV was &amp;lt;4ml when serum LH was ≥ 0.3 U/L. The median age for LH ≥0.3 was 11.3yr (IQR 10.4 – 12.2 yr), with a median TV of 3ml. In 3 boys the decrease in AMH occurred concomitantly with the increase in LH, while in 6 it occurred before.Alongside with the AMH decline, acceleration of bone age was observed in 35%, increase in growth velocity in 29%, increase in IGF1 concentrations in 24% and an increase in HOMA-IR in 26% of the boys. Concomitantly with an LH ≥0.3 U/L, acceleration of bone age was observed in 19%, increase in growth velocity in 25%, increase in IGF1 concentrations in 30% and an increase in HOMA-IR in 50% of the boys. Conclusion: The increase in testicular volume to 4ml, a classic parameter used as a marker of pubertal onset, may not be appropriate in a subgroup of children born SGA. Probably other parameters such as the increase in serum LH or the decrease in AMH should be considered. Presentation: 6/1/2024

7381 Overexpression of Makorin Ring Finger Protein 3 in the Arcuate Nucleus of Postpubertal Female Mice Impacts Neurokinin B and Kisspeptin Co-Expressing Neurons

Abstract Disclosure: S.A. Roberts: None. A. Fontes: None. S. Blau: None. M. Magnuson: None. K.M. McKnight: None. M. Sena-Esteves: None. R.S. Carroll: None. U.B. Kaiser: None. Background: Makorin ring finger protein 3 (MKRN3), an upstream inhibitor of GnRH release, is an important regulator of the age of menarche. Loss-of-function mutations in MKRN3 are the most common genetic etiology of central precocious puberty. However, its potential role in delayed puberty or hypogonadism is not well defined. In mice, expression of Mkrn3 in the hypothalamic arcuate nucleus (ARC), where kisspeptin, neurokinin B and dynorphin (KNDy) co-expressing neurons are located, is high early in life and declines before pubertal onset. Neonatal hypothalamic overexpression of Mkrn3 leads to delayed puberty in female mice and decreased neurokinin B (NKB) and kisspeptin protein levels in the ARC peripubertally. Conversely, Mkrn3-deficient peripubertal mice exhibit increased NKB protein levels in the ARC. We hypothesized that Mkrn3 overexpression in the ARC of postpubertal female mice would result in suppression of the HPG axis, manifested as hypogonadotropic hypogonadism. Methods and Results: Twelve week old adult wild type female mice were injected stereotaxically into the ARC with a novel adeno-associated virus overexpressing Mkrn3 (AAV-Mkrn3-IRES-EGFP; denoted AAV-Mkrn3) or a control virus (AAV-EGFP). Mean body weight did not differ between groups post-injection. AAV-Mkrn3 injected mice spent significantly more time (62.7%) in diestrus three to six weeks post-injection compared to controls (41.3%; P&amp;lt;0.01). Eight weeks post-injection, gonad-intact females were injected with an NKB receptor (NK3R) agonist, senktide (5 nmol or 10 nmol ip). AAV-Mkrn3 mice had a decreased peak LH response twenty minutes post-injection, compared to controls (P&amp;lt;0.001) at both doses. Peak LH levels were also reduced in response to senktide (5 nmol ip) in ovariectomized and estradiol capsule replaced (OVX+E2) AAV-Mkrn3 injected females, compared to controls (P&amp;lt; 0.001). In contrast, in both gonad-intact and OVX+E2 female mice, kisspeptin-10 (1 nmol ip) resulted in similar peak serum LH levels in AAV-Mkrn3 injected mice compared to controls. Immunohistochemistry in the ARC of intact and OVX+E2 AAV-Mkrn3 injected females showed significantly decreased NKB protein expression in AAV-Mkrn3 mice compared to controls. In response to OVX, serum LH levels increased similarly between AAV-Mkrn3 and control-injected mice. LH pulsatility in OVX females, assessed over 3 hours, showed that mean basal LH levels, number of pulses, pulse amplitude and area under the curve did not differ significantly between groups. Conclusions: These findings indicate that MKRN3 can exert inhibitory effects on the reproductive axis in female mice beyond the juvenile period, which has implications as a potential therapeutic target. The blunted response to senktide, and decreased NKB protein levels in the setting of Mkrn3 overexpression, further supports the impact of Mkrn3 on the neuropeptides and/or receptors of KNDy neurons. Presentation: 6/2/2024

8134 Hypothalamic Dlk1 Expression is Not Essential for Preventing Early Maturation of the Reproductive Axis in Female and Male Mice

Abstract Disclosure: D.B. Macedo: None. H. Kim Kyeol: None. A. Abreu: None. A. Latronico: None. R.S. Carroll: None. U.B. Kaiser: None. Background and Objectives: Inactivating mutations in Delta-like homolog 1 (DLK1), a maternally imprinted gene on chromosome 14, have been recognized as a genetic cause of central precocious puberty (CPP) in humans. It is well established that the timing of puberty, especially in females, is highly sensitive to energy stores and metabolic cues, with lower body fat negatively correlated with age at puberty and menarche. Mice lacking Dlk1 have pre- and postnatal growth retardation. Despite their considerably lower body weight (BW), we found that Dlk1 deficient females achieved puberty at the same age as controls (‘relative precocious puberty’). Moreover, Dlk1 deficiency led to activation of the reproductive axis despite lower levels of kisspeptin and leptin, an adipose tissue hormone with a permissive/stimulatory effect on metabolic control of reproduction. Dlk1 is a transmembrane protein that plays an essential role in inhibiting adipocyte differentiation and its biologically active form is soluble. Increased hypothalamic expression postnatally suggests a neuroendocrine function, but the precise mechanism by which DLK1 deficiency leads to CPP is yet to be deciphered. In this study, we aimed to investigate the role of hypothalamic Dlk1 expression on pubertal onset without the interference of diminished BW, using a conditional knockout (cKO) mouse model. Methods and Results: We generated a targeted Dlk1 knockout mouse model by crossing mice expressing Cre recombinase under the control of Nestin gene (Nes Cre), expressed primarily in neuro-epithelial cells, with mice harboring the Dlk1 gene flanked by loxP sites (Dlk1fl). Since Dlk1 is imprinted and expressed only by the paternal allele, we bred heterozygous Dlk1fl/+ male mice with Nes Cre females to obtain Dlk1fl/Cre (Dlk1 cKO), Dlk1+/Cre (Nes Cre) and Dlk1+/+ (wild type - WT). We confirmed by RT-qPCR that Dlk1 mRNA was undetectable in the mediobasal hypothalamus of Dlk1 cKO adult male mice, whereas it was present in Nes Cre and WT mice. We noted a lower BW in Nes Cre compared to WT mice, as previously reported. However, no difference in BW was observed between Dlk1 cKO and Nes Cre mice at the timing of puberty (females: Dlk1 cKO 12.6 ± 0.8 g vs. Nes Cre 13.8 ± 0.2 g, P = 0.18; males: Dlk1 cKO 12.4 ± 0.2 g vs. Nes Cre 13.1 ± 0.5 g, P = 0.26). Puberty onset, assessed by age at vaginal opening (females) and at preputial separation (males), was not affected by hypothalamic Dlk1 deletion (Dlk1 cKO: 35.6 ± 2.7 days vs. Nes Cre 34.6 ± 0.7 days, P = 0.73; Dlk1 cKO 29.0 ± 0.6 vs. Nes Cre: 30.3 ± 0.6 days, P = 0.19). Conclusion: In contrast to global Dlk1 deficiency, targeted deletion of Dlk1 from neuronal and glial cells did not affect body weight or timing of pubertal onset. These findings suggest that Dlk1 originates from peripheral tissues, such as adipocytes, to regulate reproduction and metabolism. Presentation: 6/1/2024

The Metabolic Programming of Pubertal Onset.

There is increasing evidence that maternal factors such as nutritional status (both under and over-nutrition) and diabetes, alongside prenatal exposure to endocrine disrupting chemicals (EDCs), are associated with early pubertal onset in offspring. Such children are also at increased risk of the metabolic syndrome during adolescence and young adulthood. This literature review focuses on the role of the prenatal environment in programming pubertal onset, and the impact of prenatal metabolic stressors on the declining average age of puberty. A review of all relevant literature was conducted in PubMed by the authors. The mechanism for this appears to be mediated through metabolic signals, such as leptin and insulin, on the kisspeptin-neuronal nitric oxide-gonadotropin releasing hormone (KiNG) axis. Exposed children have an elevated risk of childhood obesity and display a phenotype of hyperinsunlinaemia and hyperleptinaemia. These metabolic changes permit an earlier attainment of the nutritional "threshold" for puberty. Unfortunately, this cycle may be amplified across subsequent generations, however early intervention may help "rescue" progression of this programming.

A systematic review on the impact of SARS-CoV-2 viral infection on precocious puberty

Precocious puberty is defined as the onset of sexual characteristics before age 8 in girls and 9 in boys, with serious physical and psychological implications, including advanced bone maturation, early growth cessation, and increased behavioral issues. As per the studies done by Gupta et al precocious puberty cases have risen during the pandemic, prompting inquiries into the potential link between SARS-CoV-2 and early pubertal onset. PubMed, Scopus Web of Science, Google Scholar, and other electronic databases were used for the literature search. The search was restricted to studies published between January 2020 and July 2024. The study has shown a concerning increase in precocious puberty cases during the pandemic, with reports of a significant rise ranging from 9.8% to 93%. The increase clearly shows the concern of having a massive impact on the puberty timing in girls. The data reveal a consistent increase in the incidence of precocious puberty during the pandemic, with relative increases ranging from 0.2 average incidence per month pre-pandemic to 5.9 average per month pandemic incidence. These findings underscore the need for localized public health strategies and further research to fully understand the long-term implications of early puberty in the context of the COVID-19 pandemic. This review emphasizes the importance of continued monitoring and research to mitigate the potential long-term health risks associated with precocious puberty, including metabolic, cardiovascular, and psychological disorders.

Interactions between kisspeptin and bone: Cellular mechanisms, clinical evidence, and future potential.

The neuropeptide kisspeptin and its cognate receptor have been extensively studied in reproductive physiology, with diverse and well-established functions, including as an upstream regulator of pubertal onset, reproductive hormone secretion, and sexual behavior. Besides classical reproduction, both kisspeptin and its receptor are extensively expressed in bone-resorbing osteoclasts and bone-forming osteoblasts, which putatively permits direct bone effects. Accordingly, this sets the scene for recent compelling findings derived from in vitro experiments through to in vivo and clinical studies revealing prominent regulatory interactions for kisspeptin signaling in bone metabolism, as well as certain oncological aspects of bone metabolism. Herein, we comprehensively examine the experimental evidence obtained to date supporting the interaction between kisspeptin and bone. A comprehensive understanding of this emerging facet of kisspeptin biology is fundamental to exploiting the future therapeutic potential of kisspeptin-based medicines as a novel strategy for treating bone-related disorders.

Impact of BMI on childhood growth, pubertal timing, and bone maturation: A comprehensive review and clinical implications

Introduction: Childhood obesity and undernutrition significantly affect growth patterns, pubertal timing, and bone maturation, leading to long-term health implications. Materials and Methods: A comprehensive literature review was conducted using databases such as PubMed, Google Scholar, and Scopus. Twenty-four studies, including a total of 40,732 patients, were analyzed from two tables examining the impact of BMI, growth patterns, pubertal timing, and bone maturation. Results: Children with high BMI exhibit accelerated linear growth during early childhood, that may be driven by elevated leptin levels, which stimulate growth before puberty. Despite early growth advantages, these children experience reduced height gain during adolescence due to advanced bone maturation and earlier closure of growth plates. High BMI is strongly linked to early puberty, especially in girls, as increased adipose tissue raises leptin levels, triggering early pubertal onset. Boys, however, show variability in pubertal timing, with severe obesity sometimes delaying puberty. In contrast, children with low BMI or undernutrition demonstrate delayed linear growth and delayed puberty. Nutritional deficits lead to reduced growth velocity, delayed pubertal onset, and extended pubertal periods due to a lack of adipose tissue and hormonal deficiencies in leptin and kisspeptin. Nutritional rehabilitation promotes catch-up growth, allowing for extended growth potential by delaying growth plate closure. However, full recovery may not occur in cases of prolonged or severe undernutrition. Advanced bone age in high BMI children shortens the pubertal growth spurt, while delayed bone maturation in undernourished children offers a prolonged period for potential growth, contingent on timely nutritional support. Conclusion: Timely interventions for childhood obesity and undernutrition are critical to improving growth outcomes and preventing long-term developmental delays. Early identification, nutritional rehabilitation, and lifestyle modifications can help optimize growth and pubertal development by addressing both advanced and delayed growth trajectories.

IGF-1 and insulin receptors in LepRb neurons jointly regulate body growth, bone mass, reproduction, and metabolism.

Leptin receptor (LepRb)-expressing neurons are known to link body growth and reproduction, but whether these functions are mediated via insulin-like growth factor 1 receptor (IGF1R) signaling is unknown. IGF-1 and insulin can bind to each other's receptors, permitting IGF-1 signaling in the absence of IGF1R. Therefore, we created mice lacking IGF1R exclusively in LepRb neurons (IGF1RLepRb mice) and simultaneously lacking IGF1R and insulin receptor (IR) in LepRb neurons (IGF1R/IRLepRb mice) and then characterized their body growth, bone morphology, reproductive and metabolic functions. We found that IGF1R and IR in LepRb neurons were required for normal timing of pubertal onset, while IGF1R in LepRb neurons played a predominant role in regulating adult fertility and exerted protective effects against reproductive aging. Accompanying these reproductive deficits, IGF1RLepRb mice and IGF1R/IRLepRb mice had transient growth retardation. Notably, IGF1R in LepRb neurons was indispensable for normal trabecular and cortical bone mass accrual in both sexes. These findings suggest that IGF1R in LepRb neurons is involved in the interaction among body growth, bone development, and reproduction. Though only mild changes in body weight were detected, simultaneous deletion of IGF1R and IR in LepRb neurons caused dramatically increased fat mass composition, decreased lean mass composition, lower energy expenditure, and locomotor activity in both sexes. Male IGF1R/IRLepRb mice exhibited impaired insulin sensitivity. These findings suggest that IGF1R and IR in LepRb neurons jointly regulated body composition, energy balance, and glucose homeostasis. Taken together, our studies identified the sex-dependent complex roles of IGF1R and IR in LepRb neurons in regulating body growth, reproduction, and metabolism.

Higher peak height velocity in early maturing girls depends on insulin rather than fat mass or IGF-I

Abstract Objective Age at pubertal onset has decreased over the recent decades. Early maturing girls have longer puberty duration, and higher peak height velocity (PHV) than late maturing girls. To what extent this is generated by increased insulin-like growth factor-I (IGF-I), fat mass, or fasting insulin levels is currently unknown. Design, setting, participants A population-based study—part of the COPENHAGEN puberty study—longitudinal part. Eighty-one girls evaluated biannually for a median of 10 (2-15) visits for a total of 815 evaluations. Methods Pubertal staging, anthropometric measures, PHV, skin fold thickness (SFT), and IGF-I and fasting insulin levels were measured. Results Early maturing girls achieved similar final height compared to late maturing girls (166.1 vs 167.1 cm, P = .36). Early pubertal onset was associated with significantly greater PHV (8.7 vs 7.4 cm/year, P &amp;lt; .001) and a longer puberty duration (age at onset of breast development to age at PHV [1.8 vs 1.1 years, P &amp;lt; .001]) compared with late maturation. After correcting for age at pubertal onset, neither body mass index, SFT, nor IGF-I levels differed between early vs late maturing girls. By contrast, fasting insulin levels were significantly higher in early compared with late maturing girls 1.5, 2.0, and 3.0 years after pubertal onset (all P = .039). Conclusion Growth velocity was higher and more prolonged in early compared with late maturing girls and associated with higher insulin levels. Thus, the higher insulin levels may compensate for the shorter total growth period by intensifying the pubertal growth period. Clinical trial registration number NCT01411527.

Reliability of self-reported pubertal development scale for girls in early adolescent: a school population-based study.

The study aimed to evaluate the correlation between self-reported pubertal developmental scale (PDS) and physically assessed Tanner staging by an experienced pediatrician among girls. In a school population-based study in Zhongshan, China, we recruited 1,722 girls in grades 1-3 by a multistage stratified cluster random sampling method. Participants completed self-reported PDS questionnaire prior to physical examination. Breast development was evaluated by a female pediatrician combined with ultrasound examination for overweight/obese girls; pubic hair development was evaluated. Otherwise, we tested follicle-stimulating hormone (FSH) and luteinizing hormone (LH) for some participants. We observed a weak association between Tanner-derived composite stage (TDCS) and puberty category scores (PCS) (τ=0.288, p<0.001) among all girls. There was correlation (τ=0.314, p=0.001) between ultrasound-derived composite stage (UDCS) and PCS among overweight/obese girls. Moreover, among overweight/obese girls, PCS was positively correlated with LH (r=0.265, p=0.008), but not FSH (r=0.155, p=0.123), and when the basal LH value was greater than 0.3 mIU/mL, the proportion of PCS stage≥2 (9/18) was higher than the proportion of TDCS≥2 (5/18). As for the determination of pubertal onset, when UDCS was used as the gold standard, the specificity of PCS was 0.86 and positive predictive value was 90.00 %. There was a weak correlation between PCS and TDCS among girls early adolescence. Moreover, among overweight/obese girls, combining hormone values, ultrasonographic stage of breast, and the positive predictive value of PCS, we posit that self-reported PDS might be a more reliable method than TDCS to evaluate pubertal development among overweight/obese girls.

Updated reference values for BMD and lean mass measured by DXA in Thai children.

This study established normative references for total body less head (TBLH) BMD, lumbar spine (L1-L4) BMD, and both total and appendicular lean mass (LM) in Thai children and adolescents (aged 5-18years) using DXA. This work expands upon 2014 normative data for Thai children, which included L2-L4 BMD, total body BMD (head included), and total LM. We reanalyzed total body and lumbar spine DXA scans (Lunar Prodigy Pro, GE Healthcare; enCORE version 7.53) from 174 boys and 193 girls, using upgraded software (enCORE version 17SP2) for TBLH BMD, L1-L4 BMD, and LM analysis. The "enhanced" mode was applied for TBLH BMD and LM. Adjustments for total and appendicular LM were made relative to squared height (m2) to account for body size variability. Normative data stratified by sex and Tanner stage were generated for TBLH BMD, L1-L4 BMD, and LM indices. Weight and Tanner stage significantly determined BMD and LM. Adolescent girls exhibited higher LSBMD values due to earlier pubertal onset. Boys showed higher LM indices with more rapid gains during growth spurts. This study provides updated normative reference values for BMD (TBLH and L1-L4) and LM (total and appendicular) in Thai children and adolescents, measured via DXA. These references will enhance the assessment of low bone mass and LM deficits in Thai pediatric populations, particularly in those with chronic illnesses.

Genetic determinants of age at menarche: does the LIN28B gene play a role? A narrative review.

Menarche, the first menstrual period marking the onset of female reproduction, is a milestone of female puberty. The timing of menarche determines the timing of later phases of pubertal maturation in girls and has major implications for health later in life, including behavioral and psychosocial disorders during adolescence and fertility problems and increased risk for certain diseases in adulthood. Over the last few decades, a continuous decline in age at menarche has been noted, with environmental factors contributing to this change in the timing of menarche. However, a genetic component of age at menarche and pubertal onset has been strongly suggested by studies in families and twins wherein up to approximately 80% of the variance in puberty onset can be explained by heritability. Gene association studies have revealed several genetic loci involved in age at menarche, among which LIN28B has emerged as a key regulator of female growth and puberty. LIN28B, a human homolog of Lin28 of C. elegans, is a known RNA-binding protein that regulates let-7 microRNA biogenesis. Genome-wide association studies have identified the association of polymorphisms in the LIN28B gene with age at menarche in several population cohorts worldwide. In this paper, we review the genetic factors contributing to age of menarche, with particular focus on the identified polymorphisms in LIN28B gene.

Exposure to Per- and Polyfluoroalkyl Substances and Timing of Puberty in Norwegian Boys: Data from the Bergen Growth Study 2.

Per- and polyfluoroalkyl substances (PFAS) are widespread environmental contaminants with endocrine-disruptive properties. Their impact on puberty in boys is unclear. In this cross-sectional study, we investigated the association between PFAS exposure and pubertal timing in 300 Norwegian boys (9-16 years), enrolled in the Bergen Growth Study 2 during 2016. We measured 19 PFAS in serum samples and used objective pubertal markers, including ultrasound-measured testicular volume (USTV), Tanner staging of pubic hair development, and serum levels of testosterone, luteinizing hormone, and follicle-stimulating hormone. In addition to logistic regression of single pollutants and the sum of PFAS, Bayesian and elastic net regression were used to estimate the contribution of the individual PFAS. Higher levels of the sum of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorohexanesulfonic acid (PFHxS) were associated with later pubertal onset according to USTV (age-adjusted odds ratio (AOR): 2.20, 95% confidence interval (CI): 1.29, 3.93) and testosterone level (AOR: 2.35, 95% CI: 1.34, 4.36). Bayesian modeling showed that higher levels of PFNA and PFHxS were associated with later pubertal onset by USTV, while higher levels of PFNA and perfluoroundecanoic acid (PFUnDA) were associated with later pubertal onset by testosterone level. Our findings indicate that certain PFAS were associated with delay in male pubertal onset.

Adolescent development of anxiety-related behavior and shifts in behavioral responsiveness to estradiol in female mice.

Early pubertal onset during adolescence is consistently linked with increased risk of anxiety and depression in girls. Although estradiol tends to have anxiolytic effects in adulthood, whether sensitivity to estradiol's anxiolytic actions increases during adolescence is not clear. Using a rodent model, the current study tested the hypothesis that a shift in sensitivity to the anxiolytic effects of estradiol occurs during adolescence. To test this hypothesis, prepubertal and adult C57BL/6 female mice were ovariectomized, implanted with vehicle- or estradiol-filled silastic capsules, and behavioral tested one week later in the open field and elevated zero maze. Our hypothesis predicted that estradiol would decrease anxiety-related behavior to a greater extent in adults than in adolescent females, however, our results did not support this hypothesis. In the open field, estradiol implants significantly decreased anxiety-like behavior in adolescent females (relative to vehicle) and had little to no effect on the behavior of adults. These data suggest that adolescence is associated with a downward shift in sensitivity to the anxiolytic effects of estradiol on behavior in the open field. In contrast, although estradiol treatment did not influence anxiety-like responses in the elevated zero maze in early adolescent or adult females, adolescent females displayed significantly higher levels of anxiety-like behavior than adults. These findings demonstrate that substantial changes in anxiety-related behavior occur during adolescence, including a context-dependent shift in behavioral responsiveness to estradiol.

Tyrosine hydroxylase expression and neuronal loss in the male and female adolescent ventral tegmental area

Adolescence is a critical period of development characterized by numerous behavioral and neuroanatomical changes. While studies of adolescent neurodevelopment typically compare adolescent age groups with young adults, there are fewer studies that assess developmental trajectories within the adolescent period. In the adolescent prefrontal cortex, some maturational changes take place linearly/chronologically, while others are associated specifically with pubertal onset. The adolescent ventral tegmental area (VTA), a primary source of forebrain dopamine, is relatively understudied during this period. In the present study, dopamine neuron number, total neuron number and tyrosine hydroxylase expression are assessed in the male and female rat VTA at three timepoints: postnatal day(P) 30 (pre-pubertal), P40 (post-pubertal for females, pre-pubertal for males) and P60 (post-pubertal). There was a non-significant trend for a reduction in total VTA neuron number between P30 and P60, but there was a significant reduction in dopamine neuron number across age. The expression of tyrosine hydroxylase did not change with age. However, in a second cohort of subjects, brain tissue was collected pre-pubertal, from recently post-pubertal males and females, and young adults. In this cohort, there was a sex-specific and transient decrease in tyrosine hydroxylase expression in recently post-pubertal males. These results suggest a selective pruning of VTA dopamine cells between early adolescence and young adulthood, while pubertal onset may coincide with a rapid maturation of these neurons. These findings may have implications for psychiatric disorders associated with dopamine dysfunction that tend to manifest during adolescence.

Gene[sbnd]environment interaction between phthalate exposure and pubertal genetic polymorphisms on blood pressure variability in children: Exploring the moderating effects of lifestyle behaviours

Phthalates (PAEs) are synthetic compounds extensively employed in consumer products. Blood pressure (BP) in children can vary, the degree of visit-to-visit BP variability (VVV) is at least partially independent of BP. The interactions between PAEs exposure, pubertal-related genetic susceptibility and lifestyles on childhood VVV are not investigated. This study utilized data from a cohort collected from Oct 2017–2020 in Xiamen, China. Seven urine PAE metabolites were measured. The long-term VVV was characterized employing the standard deviation (SD) and average real variability. We constructed a genetic risk score (GRS) of pubertal-related genes and healthy lifestyle scores. Exposed to high levels of mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP) (OR=1.43, 95 %CI=1.07, 1.92) and mono-2-ethyl-5-oxohexyl phthalate (OR=1.36, 95 % CI=1.01, 1.83) was related to increased SBP-SD, and the OR for high SBP-SD related to high GRS was 1.38 (95 % CI=1.02, 1.85). Compared to participants who had low GRS and low MEHHP exposure, participants exhibiting high GRS and MEHHP levels were more likely to experience high SBP-SD (OR=2.00, P<0.05). Individuals exhibiting low GRS, low MEHHP levels, and adhering to healthy lifestyles were associated with the least probability of experiencing high SBP-SD (OR=0.31, P<0.05). Increased PAEs exposure could elevate childhood systolic VVV, and exacerbated the adverse impact of pubertal-related genetic susceptibility on the high VVV of SBP; however, healthy lifestyles might alleviate these adverse effects. Promoting healthy lifestyles and reducing PAEs exposure for preventing elevated BP variability among children is important, especially for individuals with greater genetic susceptibility to early pubertal onset. Environmental implicationBlood pressure (BP) in children can vary, as a noninvasive, inexpensive and applicable method, the extent of visit-to-visit variability (VVV) is at least partially independent of BP. The interactions between phthalates (PAEs) exposure, variants of puberty-related genes and lifestyles on VVV are not investigated. Increased childhood systolic VVV might be associated with PAEs exposure, with the associations more pronounced combined with pubertal genetic susceptibility. Yet, healthy habits could partly eliminate such adverse effects. Our study underscores the importance of advocating for healthy lifestyles and reducing exposure to PAEs, especially among individuals with high genetic susceptibility to early puberty onset.