Endocrinology of male puberty

Clinical Management and Therapy of Precocious Puberty in the Sapienza University Pediatrics Hospital of Rome, Italy

Puberty identifies the transition from childhood to adulthood. Precocious puberty is the onset of signs of pubertal development before age eight in girls and before age nine in boys, it has an incidence of 1/5000-1/10,000 with an F:M ratio ranging from 3:1 to 20:1. Precocious puberty can be divided into central, also known as gonadotropin-dependent precocious puberty or true precocious puberty, and peripheral, also recognized as gonadotropin-independent precocious puberty or precocious pseudopuberty. Thus, the main aim of this narrative report is to describe the standard clinical management and therapy of precocious puberty according to the experience and expertise of pediatricians and pediatric endocrinologists at Policlinico Umberto I, Sapienza University of Rome, Italy. In the suspicion of early sexual maturation, it is important to collect information regarding the age of onset, the speed of maturation of secondary sexual features, exposure to exogenous sex steroids and the presence of neurological symptoms. The objective examination, in addition to the evaluation of secondary sexual characteristics, must also include the evaluation of auxological parameters. Initial laboratory investigations should include serum gonadotropin levels (LH and FSH) and serum levels of the sex steroids. Brain MRI should be performed as indicated by the 2009 Consensus Statement in all boys regardless of chronological age and in all girls with onset of pubertal signs before 6 years of age. The gold standard in the treatment of central precocious puberty is represented by GnRH analogs, whereas, as far as peripheral forms are concerned, the triggering cause must be identified and treated. At the moment there are no reliable data establishing the criteria for discontinuation of GnRH analog therapy. However, numerous pieces of evidence suggest that the therapy should be suspended at the physiological age at which puberty occurs.

Luteinizing hormone β-subunit deficiency: Report of a novel LHB likely pathogenic variant and a systematic review of the published literature

CONTEXT

Selective deficiency of β-subunit of luteinizing hormone (LHB) is a rare disease with scarce data on its characteristics.

OBJECTIVES

To describe a male with LHB deficiency and systematically review the literature.

DESIGN AND PATIENTS

Description of a male patient with LHB deficiency and a systematic review of LHB deficiency patients published to date (10 males and 3 females) as per PRISMA guidelines.

RESULTS

A 36-year-old Asian Indian male presented with infertility. On evaluation, he had sexual maturity of Tanner's stage 3, low testosterone (0.23 ng/ml), low LH (0.44 mIU/ml), high follicle-stimulating hormone (FSH, 22.4 mIU/ml), and a novel homozygous missense likely pathogenic variant (p.Cys46Arg) in LHB. In the molecular dynamics simulation study, this variant interferes with heterodimerization of alpha-beta subunits. Eleven males with pathogenic variants in LHB reported to date, presented at a median age of 29 (17-38) years, most commonly with delayed puberty. Clinical and biochemical profiles were similar to those of our patient. In the majority, testosterone monotherapy modestly increased testicular volume whereas human chorionic gonadotropin (hCG) monotherapy also improved spermatogenesis. In females, oligomenorrhoea after spontaneous menarche was the most common manifestation. Ten pathogenic/likely pathogenic variants (three in-frame deletions, three missense, two splice-site, one nonsense, and one frameshift variants) have been reported in nine index patients.

CONCLUSION

We report a novel likely pathogenic LHB variant in an Asian Indian patient. The typical phenotype in male patients with LHB deficiency is delayed puberty with low testosterone, low LH, and normal to high FSH and hCG monotherapy being the best therapeutic option.

Insights into the implication of obesity in hypogonadism among adolescent boys

OBJECTIVES

This research aimed at uncovering the mechanisms behind obesity-related hypogonadism in adolescent boys and to investigate the association between anthropometric characteristics and testicular functions of these boys.

METHODS

This study included 60 adolescent boys (12-18 years) with exogenous obesity (BMI≥95th percentile) and 30 age matched lean controls (BMI=15th-85th percentile). Full clinical examination, anthropometric measurements and pubertal assessment were performed. Laboratory investigations included hemoglobin, hematocrit, lipid panel, LH, FSH, free and total testosterone, inhibin B and estradiol.

RESULTS

The results indicated the presence of positive family history of obesity in 85% of obese boys vs. 40% of the lean counterparts. Concerning SBP of obese boys, 7% were hypertensive (95th percentile), 25% were prehypertensive (between 90th and 95th percentiles) while, DBP findings showed that 33% are hypertensive and 33% are prehypertensive. Meanwhile, 13.3% of lean controls were prehypertensive. Anthropometric measurements and lipid profile values revealed a significant difference between obese and lean boys. Compared to obese boys the normal weight boys had higher levels of free testosterone (21.15 ± 2.90 pg/mL vs. 11.38 ± 3.96 pg/mL, p<0.001), total testosterone (10.59 ± 6.63 ng/dL vs. 3.23 ± 1.70 ng/dL, p<0.001), FSH (7.33 ± 3.75 mIU/mL vs. 5.63 ± 3.96 mIU/mL, p=0.026) and inhibin B (83.28 ± 27.66 pg/mL vs. 62.90 ± 17.85 pg/mL, p=0.001) and they registered lower level of estradiol (18.48 ± 7.33 pg/mL vs. 40.20 ± 7.91 pg/mL, p<0.001). In obese boys, BMI SDS significantly correlated with lipid profile and estradiol whereas, it showed significant negative correlation with LH, free and total testosterone and inhibin B. Penile length significantly correlated with LH while it revealed significant negative correlation with cholesterol.

CONCLUSIONS

This study evidenced a close association between obesity and hypogonadism in adolescent boys which could be due to the increased estradiol level and decreased T/E2 ratio.

Developmental sex differences in the peri-pubertal pattern of hypothalamic reproductive gene expression, including Kiss1 and Tac2, may contribute to sex differences in puberty onset

The mechanisms regulating puberty still remain elusive, as do the underlying causes for sex differences in puberty onset (girls before boys) and pubertal disorders. Neuroendocrine puberty onset is signified by increased pulsatile GnRH secretion, yet how and when various upstream reproductive neural circuits change developmentally to govern this process is poorly understood. We previously reported day-by-day peri-pubertal increases (Kiss1, Tac2) or decreases (Rfrp) in hypothalamic gene expression of female mice, with several brain mRNA changes preceding external pubertal markers. However, similar pubertal measures in males were not previously reported. Here, to identify possible neural sex differences underlying sex differences in puberty onset, we analyzed peri-pubertal males and directly compared them with female littermates. Kiss1 expression in male mice increased over the peri-pubertal period in both the AVPV and ARC nuclei but with lower levels than in females at several ages. Likewise, Tac2 expression in the male ARC increased between juvenile and older peri-pubertal stages but with levels lower than females at most ages. By contrast, both DMN Rfrp expressionand Rfrp neuronal activation strongly decreased in males between juvenile and peri-pubertal stages, but with similar levels as females. Neither ARC KNDy neuronal activation nor Kiss1r expression in GnRH neurons differed between males and females or changed with age. These findings delineate several peri-pubertal changes in neural populations in developing males, with notable sex differences in kisspeptin and NKB neuron developmental patterns. Whether these peri-pubertal hypothalamic sex differences underlie sex differences in puberty onset deserves future investigation.

Association of Anti-Mullerian Hormone with C-Reactive Protein in Men

While serum anti-mullerian hormone (AMH) levels are inversely associated with all-cause mortality in men, the underlying mechanisms are unclear. Elevated levels of inflammation, also associated with all-cause mortality, and may be the link between AMH and mortality. Hence, we examined the association of AMH with serum c-reactive protein (CRP), a biomarker of inflammation, in men. We included men ≥20 years from the National Health and Nutrition Examination Survey (1999–2004). We used survey weight-adjusted linear regression to examine the association between AMH and CRP without and with adjustment for age, race, body mass index (BMI), smoking, hypertension, diabetes, cholesterol, glomerular filtration rate (GFR), testosterone, androstenedione, and sex hormone binding globulin. Of the 949 men, 212 (22%) were elderly, 493 (52%) Caucasian, 254 (27%) current smokers, 100 (10%) diabetics, and 312 (33%) had hypertension. Mean (SD) AMH was 8.4 (7.2) ng/mL and median (IQR) CRP level was 0.17 (3) mg/L. Using linear regression, each 10 ng/mL rise in AMH was associated with 0.09 mg/dL (95%CI = −0.14 to −0.03; p = 0.002) decrease before and 0.08 mg/dL (95%CI = −0.13 to −0.02; p = 0.004) decrease in CRP after adjusting for potential confounders. Similarly, men in the highest quartile of AMH had significantly lower CRP compared to those in the lowest quartile (unadjusted difference = −0.19 mg/dL; 95%CI = −0.31 to −0.06; p = 0.006, adjusted difference = −0.16 mg/dL; 95%CI = −0.3 to −0.01; p = 0.035). We found an independent, robust, and inverse association between CRP and AMH in men. Effect of AMH on mortality may be through amelioration of inflammation.

Hypogonadism and Cryptorchidism

Congenital cryptorchidism (undescended testis) is one of the most common congenital urogenital malformations in boys. Prevalence of cryptorchidism at birth among boys born with normal birth weight ranges from 1.8 to 8.4%. Cryptorchidism is associated with a risk of low semen quality and an increased risk of testicular germ cell tumors. Testicular hormones, androgens and insulin-like peptide 3 (INSL3), have an essential role in the process of testicular descent from intra-abdominal position into the scrotum in fetal life. This explains the increased prevalence of cryptorchidism among boys with diseases or syndromes associated with congenitally decreased secretion or action of androgens, such as patients with congenital hypogonadism and partial androgen insensitivity syndrome. There is evidence to support that cryptorchidism is associated with decreased testicular hormone production later in life. It has been shown that cryptorchidism impairs long-term Sertoli cell function, but may also affect Leydig cells. Germ cell loss taking place in the cryptorchid testis is proportional to the duration of the condition, and therefore early orchiopexy to bring the testis into the scrotum is the standard treatment. However, the evidence for benefits of early orchiopexy for testicular endocrine function is controversial. The hormonal treatments using human chorionic gonadotropin (hCG) or gonadotropin-releasing hormone (GnRH) to induce testicular descent have low success rates, and therefore they are not recommended by the current guidelines for management of cryptorchidism. However, more research is needed to assess the effects of hormonal treatments during infancy on future male reproductive health.

Changing bulking agent may require change in injection volume for endoscopic treatment of vesicoureteral reflux

Introduction:

Various bulking agents were utilized for endoscopic correction of VUR. A study reviewing multi-institutional data showed that the amount of injection material has increased over time with the purpose of improving success rates, which also resulted in costs. We noticed an opposite trend in our center since we started using a new bulking agent. The aim of this study was to evaluate evolution of our practice with different bulking agents.

Patients and Methods:

Records of VUR patients who underwent subureteric injection with polyacrylate polyalcohol copolymer (PPC) and dextronomere hyaluronic acide (DxHA) between 2005 and 2014 were reviewed. Variation of different parameters throughout the study period was evaluated along with the success rate. Success was defined as complete resolution of reflux.

Results:

A total of 260 patients with 384 refluxing units were included. The success rate was higher in PPC group compared to DxHA group. There was no statistically significant difference between years regarding distribution of VUR grade, body weight, patient height, and age in PPC group. Despite significant reduction in injection volume, success rate did not decrease through the years with PPC.

Conclusion:

Different bulking agents may require different injection volumes to achieve the same success rate in endoscopic treatment of vesicoureteral reflux. Habits gained with previous experience using other materials should be revised while using a new agent.

Sleep, circadian rhythm and body weight: parallel developments

Circadian alignment is crucial for body-weight management, and for metabolic health. In this context, circadian alignment consists of alignment of sleep, meal patterns and physical activity. During puberty a significant reduction in sleep duration occurs, and pubertal status is inversely associated with sleep duration. A consistent inverse association between habitual sleep duration and body-weight development occurs, independent of possible confounders. Research on misalignment reveals that circadian misalignment affects sleep-architecture and subsequently disturbs glucose–insulin metabolism, substrate oxidation, leptin- and ghrelin concentrations, appetite, food reward, hypothalamic–pituitary–adrenal-axis activity and gut-peptide concentrations enhancing positive energy balance and metabolic disturbance. Not only aligning meals and sleep in a circadian way is crucial, also regular physical activity during the day strongly promotes the stability and amplitude of circadian rhythm, and thus may serve as an instrument to restore poor circadian rhythms. Endogenicity may play a role in interaction of these environmental variables with a genetic predisposition. In conclusion, notwithstanding the separate favourable effects of sufficient daily physical activity, regular meal patterns, sufficient sleep duration and quality sleep on energy balance, the overall effect of the amplitude and stability of the circadian rhythm, perhaps including genetic predisposition, may integrate the separate effects in an additive way.

Hormone Inhibition During Mini-Puberty and Testicular Function in Male Rats

BACKGROUND

The mini-pubertal period of almost six hours in neonatal male rats is thought to be an important stage in sexual development.

OBJECTIVES

The aim of this study was to investigate the effect of hormone inhibition during mini-puberty on testicular function in male rats.

MATERIALS AND METHODS

We measured serum testosterone (T), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels in male rats at different time points after birth by enzyme linked immunosorbent assay (ELISA) and established a "no mini-puberty" model by ether inhalation. The mRNA expression levels of testicular androgen receptor (AR), insulin-like growth factor 3 (INSL3), anti-Mullerian hormone (AMH), and ghrelin were determined by real-time polymerase chain reaction (PCR) assays on postnatal days 45 and 75. Testicular tissue biopsies were stained with hematoxylin and eosin (H & E) and the structure, number and maturity of testis cells (including spermatogenic, Sertoli, and Leydig cells) were observed under microscopy at the same time.

RESULTS

Serum T and LH levels peaked at two hours after birth, while FSH peaked at hour 0, and bilateral testicular weight peaked at four hours after birth. The rats that underwent ether inhalation five minutes after birth had markedly reduced serum hormone levels. The mini-puberty model group revealed visible morphologic alterations in the tests on postnatal day 45. Then, on postnatal day 75, the mRNA expression level of AMH significantly decreased (P < 0.05) in the same group.

CONCLUSIONS

The inhibition of mini-puberty period in male rats was demonstrated to have an effect on their testicular function to some extent.

Sleep efficiency as a determinant of insulin sensitivity in overweight and obese adolescents

Insulin resistance (IR) occurs in a transient manner during puberty. Obese adolescents may be at risk for persistent IR during puberty. The objective of the study is to review the literature on the association of the anthropometry and lifestyle characteristics with insulin sensitivity in overweight and obese adolescents, and include data from a new study. Relevant papers were selected and reviewed. In addition, 137 overweight and obese adolescents (42 male/95 female, age 14.4 ± 2.3 years, BMI z-score +3.3 ± 0.7, HOMA-IR 3.4 ± 1.8) from the Centre for Overweight Adolescent and Children's Healthcare (MUMC+) were included in this study. Anthropometrics, Tanner stages, sleep characteristics, food intake behaviour and physical activity were determined, and possible associations with homeostasis model assessment of insulin resistance (HOMA-IR) were tested.

RESULTS

Overweight and obese adolescents with unfavourable fat partitioning and family history of NIDDM are at risk for persistent IR. Overweight and obese adolescents from the new cohort showed a higher HOMA-IR postpubertally. BMI z-score, age, pubertal stage and prepubertally total sleeping time (TST) and sleep efficiency (SE) were identified as significant contributors. Overweight and obese adolescents showed a persistently higher instead of transiently higher HOMA-IR during puberty, associated with BMI z-score, age, pubertal stage and prepubertally less TST and SE.

Mini puberty and its interpretation

Gonadotropins which are high in the middle of the fetal life are measured to be considerably low in the cord blood and estrogen is found to be high in the cord blood. Gonodotropins are supressed by estrogen. After delivery, the hypothalamo-pituitary-gonadal axis is activated when estrogen is eliminated and a hormone profile which reaches pubertal levels is established. These changes are called mini puberty. In boys, long-term testicular functions and sperm production are regulated with mini puberty and mini puberty contributes to masculinization of the brain. The role of mini puberty in female newborns is not known. Central hypogonadism, Turner syndrome and ovarian hyperstimulation in preterm babies may be diagnosed with evaluation of mini puberty. In this article, mini puberty and related problems were reviewed and the importance of this issue was emphasized.

In utero exposure to alcohol and puberty in boys: a pregnancy cohort study

OBJECTIVES

Epidemiological studies have raised concerns about the reproductive consequences of in utero exposure to alcohol. Maternal lifestyle factors have been associated with altered pubertal development, but the impact of prenatal alcohol exposure on male puberty is unknown. Thus, the objective was to explore whether prenatal alcohol exposure alters pubertal development in boys.

SETTING

Follow-up of a Danish pregnancy cohort.

PARTICIPANTS

Sons (N=2522) of women who were enrolled in a Danish pregnancy cohort between 1984 and 1987.

PRIMARY AND SECONDARY OUTCOME MEASURES

Indicators of pubertal development, assessed by age at first nocturnal emission, voice break, acne and regular shaving.

RESULTS

We found a tendency towards a later age at first nocturnal emission and voice break following in utero exposure to binge drinking. Boys exposed to ≥5 binge drinking episodes during pregnancy experienced their first nocturnal emission 7.3 months (95% CI -2.8 to 17.4) later and voice break 4.9 months (95% CI -0.6 to 10.4) later than the unexposed boys. Results for average weekly alcohol consumption were in the same direction, but differences were smaller and not statistically significant.

CONCLUSIONS

We found no strong support for the hypothesis that in utero exposure to weekly alcohol consumption is a risk factor for altered pubertal development, but a tendency towards delayed pubertal development among boys exposed to binge drinking during fetal life was observed. Longitudinal studies, with data collected as children go through puberty, are needed to explore this further.

Methylation potential associated with diet, genotype, protein, and metabolite levels in the Delta Obesity Vitamin Study

Micronutrient research typically focuses on analyzing the effects of single or a few nutrients on health by analyzing a limited number of biomarkers. The observational study described here analyzed micronutrients, plasma proteins, dietary intakes, and genotype using a systems approach. Participants attended a community-based summer day program for 6-14 year old in 2 years. Genetic makeup, blood metabolite and protein levels, and dietary differences were measured in each individual. Twenty-four-hour dietary intakes, eight micronutrients (vitamins A, D, E, thiamin, folic acid, riboflavin, pyridoxal, and pyridoxine) and 3 one-carbon metabolites [homocysteine (Hcy), S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH)], and 1,129 plasma proteins were analyzed as a function of diet at metabolite level, plasma protein level, age, and sex. Cluster analysis identified two groups differing in SAM/SAH and differing in dietary intake patterns indicating that SAM/SAH was a potential marker of nutritional status. The approach used to analyze genetic association with the SAM/SAH metabolites is called middle-out: SNPs in 275 genes involved in the one-carbon pathway (folate, pyridoxal/pyridoxine, thiamin) or were correlated with SAM/SAH (vitamin A, E, Hcy) were analyzed instead of the entire 1M SNP data set. This procedure identified 46 SNPs in 25 genes associated with SAM/SAH demonstrating a genetic contribution to the methylation potential. Individual plasma metabolites correlated with 99 plasma proteins. Fourteen proteins correlated with body mass index, 49 with group age, and 30 with sex. The analytical strategy described here identified subgroups for targeted nutritional interventions.

Further characterization of atypical features in auriculocondylar syndrome caused by recessive PLCB4 mutations

Auriculocondylar syndrome (ACS) is a branchial arch syndrome typically inherited in an autosomal dominant fashion. Patients with ACS display the following core symptoms with varying severity: a specific malformation of the external ear, known as a "question mark ear," micrognathia and mandibular condyle hypoplasia. Recently, phospholipase C, β 4 (PLCB4) mutations were identified as the major cause of autosomal dominant ACS, with mutations of the PLCB4 catalytic domain predicted to have a dominant negative effect. In addition, one ACS patient born to related parents harbored a homozygous partial deletion of PLCB4, and presented with ACS plus central apnea and macropenis; these features had not been previously reported in association with ACS. His parents, each with a heterozygous partial PLCB4 deletion, were phenotypically normal, suggesting autosomal recessive inheritance of ACS, with complete loss of function of PLCB4 predicted in the patient. We herein describe two brothers with ACS caused by compound heterozygous splice site mutations in PLCB4. The patients were born to the same unrelated and healthy parents, with each parent harboring one of the mutations, indicating autosomal recessive ACS. Both patients reported here had mixed apneas, gastrointestinal transit defects and macropenis, in addition to typical craniofacial features of ACS. This is the first example of ACS caused by compound heterozygous splice site mutations in PLCB4, the second autosomal recessive case of ACS confirmed by molecular analysis, and strengthens the link between complete loss of function of PLCB4 and extra-craniofacial features.

Sleep duration and body-weight development during puberty in a Dutch children cohort

BACKGROUND

Short sleep duration is associated with obesity during childhood and adulthood.

OBJECTIVE

The objective of our study was to investigate the relationship between sleep duration and body mass index (BMI) from Tanner stages 1 to 5 in a Dutch children cohort.

DESIGN

In 98 children, anthropometric measurements and leptin concentrations were measured from age 7 to 16 years; body composition, physical activity (Baecke questionnaire), hours television viewing and self-reported sleep duration were measured yearly from age 12 to 16 years. Moreover, the polymorphisms of the FTO gene (rs9939609) and parental BMI's were determined.

RESULTS

At Tanner stages 1-5 sex differences were observed in height, body weight, waist circumference, fat mass per squared meter height and leptin concentrations per kg fat mass. Inverse relationships were observed between the change in BMI (kg m(-2)) and the change in hours of sleep per night (h) from Tanner stages 1 to 4 (r=-0.68, P<0.001), from Tanner stages 2 to 5 (r=-0.35, P<0.05) and from Tanner stages 1 to 5 (r=-0.33, P<0.05). Univariate analysis of variance showed that with progressive Tanner stages, BMI increases and sleep duration decreases in an interrelated way independent of possible confounders (R(2)=0.38, P<0.02).

CONCLUSION

Changes in BMI during puberty were inversely related to changes in sleep duration, independent of possible confounders.

Normal spermatogenesis in a man with mutant luteinizing hormone

Men with mutations in LHB, the gene encoding the beta subunit of luteinizing hormone (LHB), have azoospermia with absent or few fetal Leydig cells. We report a mutation in LHB in a man and his sister. The man presented with absence of virilization, undetectable luteinizing hormone, and a low serum testosterone level. He had complete spermatogenesis with a normal sperm count. The mutant luteinizing hormone had a low level of partial activity in vitro. We concluded that the residual luteinizing hormone activity, resulting in the expression of steroidogenic enzymes in few mature Leydig cells producing small amounts of intratesticular testosterone (20.2 ng per gram), was sufficient for complete and quantitatively normal spermatogenesis.