Hypothalamic mechanisms of obesity-associated disturbance of hypothalamic-pituitary-ovarian axis

Bmal1 regulates female reproduction in mice via the hypothalamic-pituitary-ovarian axis

The hypothalamic-pituitary-gonadal axis (HPG) is the key neuroendocrine axis involved in reproductive regulation. Brain and muscle ARNT-like protein 1 (Bmal1) participates in regulating the metabolism of various endocrine hormones. However, the regulation of Bmal1 on HPG and female fertility is unclear. This study aims to explore the regulation of female reproduction by Bmal1 via the HPG axis in mice. Bmal1-knockout (Ko) mice were generated using the CRISPR/Cas9 technology. The structure, function, and estrous cycle of ovarian in Bmal1 Ko female mice were measured. The key genes and proteins of the HPG axis involved in regulating female reproduction were examined through transcriptome analysis and then verified by RT-PCR, immunohistochemistry, and western blot. Furthermore, the fertility of female mice was detected after intervening prolactin (PRL) and progesterone (Pg) in Bmal1 ko mice. The number of offspring and ovarian weight were significantly lower in Bmal1-Ko mice than in wild-type (Wt) mice. In Bmal1-Ko mice, ovarian cells were arranged loosely and irregularly, and the total number of follicles was significantly reduced. No corpus luteum was found in the ovaries. Vaginal smears revealed that Bmal1-Ko mice had an irregular estrus cycle. In Bmal1-Ko mice, Star expression was decreased, PRL and luteinizing hormone (LH) levels were increased, and dopamine (DA) and Pg levels were decreased. Inhibition of PRL partially recovered the estrous cycle, corpus luteum formation, and Star expression in the ovaries. Pg supplementation promoted embryo implantation in Bmal1-Ko female mice. Bmal1 Ko increases serum PRL levels in female mice likely by reducing DA levels, thus affecting luteal formation, resulting in decreased Star expression and Pg production, hindering female reproduction. Inhibition of PRL or restoration of Pg can partially restore reproductive capacity in female Bmal1-Ko mice. Thus, Bmal1 may regulate female reproduction via the HPG axis in mice, suggesting that Bmal1 is a potential target to treat female infertility.

Laparoscopic sleeve gastrectomy for premenstrual syndrome symptoms in patients with obesity

BACKGROUND

Premenstrual syndrome (PMS) is a pathological condition characterized by a series of abnormal physical, psychological, and behavioral symptoms. We evaluated the effectiveness of laparoscopic sleeve gastrectomy (LSG) in the treatment of patients with obesity and PMS.

METHODS

In this case-control study, 131 patients with obesity (BMI ≥ 27.5 kg/cm2) diagnosed with moderate-to-severe PMS from March 2018 to March 2022 were prospectively selected to undergo LSG or not at their own discretion. Participants self-reported their PMS severity using the Premenstrual Syndrome Screening Tool. Among them, 68 patients chose LSG surgery, and 63 control group patients were followed up without surgery. Data were recorded at baseline and at 3 months post-treatment. We used a multivariate analysis to assess the improvement in PMS symptoms and associated factors.

RESULTS

Of the 131 patients with obesity and PMS, the improvement rate of PMS in the LSG group was 57.35% (n = 39), while the improvement rate of PMS in the control group was 25.40% (n = 16). Furthermore, our study revealed that surgery is an independent factor affecting the improvement of patients with PMS. Additionally, there was a correlation between alcohol use, T2DM and obesity-related metabolic diseases, and BMI with PMS. The changes in BMI, testosterone, and estradiol(E2) levels may also contribute to the improvement of patients with obesity and PMS.

CONCLUSION

LSG can improve the management of obesity in patients with PMS to some extent. Changes in BMI, testosterone, and E2 may be indicative of improvement in patients with obesity and PMS.

A combination of gliclazide and metformin attenuates obesity-induced polycystic ovary syndrome in female Wistar rats

Presently, it is known that the progression of obesity concomitantly leads to polycystic ovary syndrome and infertility. This study aimed to evaluate the potential effects of metformin (M; insulin secretagogues) and gliclazide (G; insulin sensitizer) alone and their combination at different doses to treat obesity-induced PCOS. High high-fat diet was given to all female Wistar rats for nine weeks to induce obesity except for the normal control group which received a normal chow diet. Estradiol valerate (0.8 mg/kg) was also given to all obese rats to induce polycystic ovarian syndrome. After the induction, M (100, 300 mg/kg) and G (5, 10 mg/kg) were given orally either individually or in combination for 28 days. The notable (p < 0.0001) reduction in body weight and blood glucose level was observed in treatment groups in contrast to disease control (DCG). The marked (p < 0.05-0.0001) decrease in hemocylated hemoglobin, serum insulin, cholesterol, triglycerides, and testosterone was observed in treated groups, notably in combination groups (M100+G10 mg/kg) in contrast to DCG. There was a considerable (p < 0.01-0.0001) increase in progesterone E2, estradiol, luteinizing, and follicle-stimulating hormones in treated groups as compared to DCG. Treatment with M and G treated groups also exhibited marked (p < 0.05-0.0001) increases in SOD, CAT, and GSH while decreased in NO and MDA levels in ovary tissue as evidenced by the histological study of the ovary. Treatment with M and G alone and in combination significantly (p < 0.0001) restored the serum IL-6, NrF2, and NF-κB levels as compared to DCG. The results inveterate that the M and G combination (M100+G10, and M300+G10) was useful in treating obesity-induced infertility due to antioxidant properties, hypolipidemic effects, and modulation of inflammatory markers.

Hypothalamic-Ovarian axis and Adiposity Relationship in Polycystic Ovary Syndrome: Physiopathology and Therapeutic Options for the Management of Metabolic and Inflammatory Aspects

PURPOSE OF REVIEW

The goal of the present review is to address the main adiposity-related alterations in Polycystic Ovary Syndrome (PCOS) focusing on hypothalamic-pituitary-ovarian (H-P-O) axis and to provide an overview of nutraceutical and pharmacological therapeutic strategies.

RECENT FINDINGS

Female reproduction is a complex and delicate interplay between neuroendocrine signals involving the H-P-O axis. Elements that disrupt the balance of these interactions can lead to metabolic and reproductive disorders, such as PCOS. This disorder includes menstrual, metabolic, and biochemical abnormalities as well as hyperandrogenism, oligo-anovulatory menstrual cycles, insulin resistance, and hyperleptinemia which share an inflammatory state with other chronic diseases. Moreover, as in a self-feeding cycle, high androgen levels in PCOS lead to visceral fat deposition, resulting in insulin resistance and hyperinsulinemia, further stimulating ovarian and adrenal androgen production. In fact, regardless of age and BMI, women with PCOS have more adipose tissue and less lean mass than healthy women. Excessive adiposity, especially visceral adiposity, is capable of affecting female reproduction through direct mechanisms compromising the luteal phase, and indirect mechanisms as metabolic alterations able to affect the function of the H-P-O axis. The intricate crosstalk between adiposity, inflammatory status and H-P-O axis function contributes to the main adiposity-related alterations in PCOS, and alongside currently available hormonal treatments, nutraceutical and pharmacological therapeutic strategies can be exploited to treat these alterations, in order to enable a more comprehensive synergistic and tailored treatment.

Cellular atlases of ovarian microenvironment alterations by diet and genetically-induced obesity

Obesity, which can arise from genetic or environmental factors, has been shown to cause serious damages to the reproductive system. The ovary, as one of the primary regulators of female fertility, is a complex organ comprised of heterogeneous cell types that work together to maintain a normal ovarian microenvironment (OME). Despite its importance, the effect of obesity on the entire ovary remains poorly documented. In this study, we performed ovary single-cell and nanoscale spatial RNA sequencing to investigate how the OME changed under different kinds of obesity, including high-fat diet (HFD) induced obesity and Leptin ablation induced obesity (OB). Our results demonstrate that OB, but not HFD, dramatically altered the proportion of ovarian granulosa cells, theca-interstitial cells, luteal cells, and endothelial cells. Furthermore, based on the spatial dynamics of follicular development, we defined four subpopulations of granulosa cell and found that obesity drastically disrupted the differentiation of mural granulosa cells from small to large antral follicles. Functionally, HFD enhanced follicle-stimulating hormone (FSH) sensitivity and hormone conversion, while OB caused decreased sensitivity, inadequate steroid hormone conversion, and impaired follicular development. These differences can be explained by the differential expression pattern of the transcription factor Foxo1. Overall, our study provides a powerful and high-resolution resource for profiling obesity-induced OME and offers insights into the diverse effects of obesity on female reproductive disorders.

Multi-Organ Increase in Norepinephrine Levels after Central Leptin Administration and Diet-Induced Obesity

Autonomic innervation is important to regulate homeostasis in every organ of the body. The sympathetic nervous system controls several organs associated with metabolism and reproduction, including adipose tissue, the liver, and the ovaries. The sympathetic nervous system is controlled within the central nervous system by neurons located in the hypothalamus, which in turn are regulated by hormones like leptin. Leptin action in the hypothalamus leads to increased sympathetic activity in the adipose tissue. In this short report, we propose that leptin action in the brain also controls the sympathetic innervation of other organs like the liver and the ovary. We performed two experiments: We performed an intracerebroventricular (ICV) injection of leptin and measured norepinephrine levels in several organs, and we used a validated model of overnutrition and obesity to evaluate whether an increase in leptin levels coexists with high levels of norepinephrine in the liver and ovaries. Norepinephrine was measured by ELISA in adipose tissue and by HPLC-EC in other tissues. Leptin was measured by ELISA. We found that the ICV injection of leptin increases norepinephrine levels in several organs, including the liver and ovaries. Also, we found that diet-induced obesity leads to an increase in leptin levels while inducing an increase in norepinephrine levels in the liver and ovaries. Finally, since hyperactivity of the sympathetic nervous system is observed both in non-alcoholic fatty liver disease and polycystic ovary syndrome, we think that an increase in norepinephrine levels induced by hyperleptinemia could be involved in the pathogenesis of both diseases.

Potential for NPY receptor-related therapies for polycystic ovary syndrome: an updated review

Polycystic ovary syndrome (PCOS) is a complex endocrine disease that can cause female infertility and bring economic burden to families and to society. The clinical and/or biochemical manifestations include hyperandrogenism, persistent anovulation, and polycystic ovarian changes, often accompanied by insulin resistance and obesity. Although its pathogenesis is unclear, PCOS involves the abnormal regulation of the hypothalamic-pituitary-ovarian axis and the abnormal activation of GnRH neurons. Neuropeptide Y (NPY) is widely distributed in the arcuate nucleus of the hypothalamus and functions as the physiological integrator of two neuroendocrine systems, one governing feeding and the other controlling reproduction. In recent years, an increasing number of studies have focused on the improvement of the reproductive and metabolic status of PCOS through the therapeutic application of NPY and its receptors. In this review, we summarize the central and peripheral regulation of NPY and its receptors in the development of PCOS and discuss the potential for NPY receptor-related therapies for PCOS.

Subacute high-refined carbohydrate diet leads to abnormal reproductive control of the hypothalamic-pituitary axis in female rats

We previously reported that female rats placed on a diet containing refined carbohydrates (HCD) resulted in obesity and reproductive abnormalities, such as high serum LH concentration and abnormal ovarian function. However, the impacts at the hypothalamic-pituitary (HP) function, specifically regarding pathways linked to reproductive axis modulation are unknown. In this study, we assessed whether subacute feeding with HCD results in abnormal reproductive control in the HP axis. Female rats were fed with HCD for 15 days and reproductive HP axis morphophysiology was assessed. HCD reduced hypothalamic mRNA expression (Kiss1, Lepr, and Amhr2) and increased pituitary LHβ+ cells. These changes likely contribute to the increase in serum LH concentration observed in HCD. Blunted estrogen negative feedback was observed in HCD, with increased kisspeptin protein expression in the arcuate nucleus of the hypothalamus (ARH), lower LHβ+ cells and LH concentration in ovariectomized (OVX)+HCD rats. Thus, these data suggest that HCD feeding led to female abnormal reproductive control of HP axis.

Clinical Significance of Plasma Leptin and Its Receptors mRNA Expression in Craniopharyngiomas: A Prospective Study

Craniopharyngioma (CP) is a benign tumor with a high rate of obesity and frequent recurrence. Moreover, the role of leptin/leptin receptors axis in obesity and the prognosis of CP is still unknown. Plasma leptin concentration and mRNA expression of leptin receptors were assessed in patients with CP. Moreover, the association between leptin/leptin receptors axis, weight-related outcomes, and progression-free survival (PFS) were explored in CP patients. Leptin receptors overexpressed in CP tumor tissue were compared to normal brain tissue (p < 0.05); compared to healthy controls, the concentration of leptin was elevated in CP with or without matched age, sex, and body mass index (BMI) (p < 0.05). The high plasma leptin level was an independent risk predictor for significant weight gain (adjusted odds ratio (aOR) = 2.29, and p = 0.030) and new-onset obesity (aOR = 6.64, and p = 0.016). High plasma leptin level (adjusted hazard ratio (aHR) = 3.74, and p = 0.011) and leptin receptor (LEPR) mRNA expression (aHR = 3.12, and p = 0.045) were independent risk factors for poor PFS in CP. Inappropriately elevated leptin relative to BMI and its failure to inhibit further weight gain indicate the existence of leptin resistance in patients with CP. Leptin and LEPR were independent predictors for PFS of patients with CP. The leptin/leptin receptors axis may be a potential therapeutic target for obesity in patients with CP.

The impact of weight loss for obese infertile women prior to in vitro fertilization: A retrospective cohort study

Obesity is detrimental to general health and also reproductive health. This study aimed to evaluate whether weight reduction in obese infertile women prior to in vitro fertilization reduces the total gonadotropin dose and improves pregnancy outcomes. This retrospective cohort study was performed at the Jiaxing Maternity and Child Health Care Hospital between January 2017 and January 2022, and 197 women were enrolled. The women were divided into 2 groups according to the weight loss goal of 5%: weight reduction group A (≥weight loss goal of 5%) and control group A ( Collapse

Key Words

• body mass index
• clinical pregnancy rate
• in vitro fertilization
• obese
• weight loss

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MESH Headings

• Child
• Pregnancy
• Female
• Humans
• Infertility, Female
• Retrospective Studies
• Fertilization in Vitro
• Obesity
• Pregnancy Rate
• Live Birth
• Gonadotropins
• Weight Loss

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Grants Collapse

Affiliation(s)

Chunjuan Shen Centre for Reproductive Medicine, Jiaxing University Affiliated Maternity and Child Hospital, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, Zhejiang, China
Weiping Fu Centre for Reproductive Medicine, Jiaxing University Affiliated Maternity and Child Hospital, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, Zhejiang, China
Chunxia Fang Centre for Reproductive Medicine, Jiaxing University Affiliated Maternity and Child Hospital, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, Zhejiang, China
Huan Zhou Traditional Chinese Medicine Department, Jiaxing University Affiliated Maternity and Child Hospital, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, Zhejiang, China
Liping Wang Centre for Reproductive Medicine, Jiaxing University Affiliated Maternity and Child Hospital, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, Zhejiang, China

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Benefits and Risks of Bariatric Surgery on Women's Reproductive Health: a Narrative Review

Bariatric surgery (BS) is escalating as the most efficient and endurable therapy for severe obesity. Women's reproductive health is essential to women's quality of life and is receiving increasing attention. However, despite the high prevalence of BS among women, the effect of BS on reproductive health remains underemphasis. The purpose of this narrative review is to provide an overview of BS on women's reproductive health, including their reproductive health before, during, and after pregnancy. Although limited attention has been given, current evidence highlights the substantial implications of bariatric surgery on reproductive health and reminds us of the importance of adopting decision-making conversations about reproductive health before bariatric surgery.

Perception and Practice of Bariatric Surgery and Reproductive Health in Women: a Cross-sectional Study of Chinese Bariatric Surgeons

BACKGROUND AND PURPOSE

Western studies have explored bariatric surgeons concerning their views on bariatric surgery (BS) and reproductive health, but Asian data were lacking. The aim of this study was to explore the perception and practice of bariatric surgeons on the reproductive health of female patients who underwent BS in China to better guide clinical practice and improve clinical outcomes.

METHOD

An online questionnaire of 31 questions developed by bariatric surgeons was collected by sending to one online communication group (WeChat group) whose members are Chinese bariatric surgeons.

RESULT

A total of 87 bariatric surgeons from mainland China were surveyed. Almost all (97.7%, 85/87) surgeons considered the reproductive health conversation for women who underwent BS to be important or very important. Only 1/4 of surgeons routinely discuss reproductive health-related issues with patients, and only 56% of doctors always ask patients for postoperative contraception. Less than 20% of bariatric surgeons have full knowledge of postoperative contraception, and nearly 40% of them believe that gynecologists should be responsible for providing contraception. More than 35% of bariatric surgeons have never been involved in the co-management of pregnancy in patients with a history of BS.

CONCLUSION

Although most bariatric surgeons are aware of the importance of female reproductive health, there is a large gap in the perception and clinical practice of bariatric surgeons in terms of reproductive health. It is necessary to further strengthen the education of bariatric surgeons and enhance multidisciplinary cooperation with gynecology, obstetrics, and other disciplines to bring better clinical outcomes.

The Significance of Hypothalamic Inflammation and Gliosis for the Pathogenesis of Obesity in Humans

Accumulated preclinical literature demonstrates that hypothalamic inflammation and gliosis are underlying causal components of diet-induced obesity in rodent models. This review summarizes and synthesizes available translational data to better understand the applicability of preclinical findings to human obesity and its comorbidities. The published literature in humans includes histopathologic analyses performed postmortem and in vivo neuroimaging studies measuring indirect markers of hypothalamic tissue microstructure. Both support the presence of hypothalamic inflammation and gliosis in children and adults with obesity. Findings predominantly point to tissue changes in the region of the arcuate nucleus of the hypothalamus, although findings of altered tissue characteristics in whole hypothalamus or other hypothalamic regions also emerged. Moreover, the severity of hypothalamic inflammation and gliosis has been related to comorbid conditions, including glucose intolerance, insulin resistance, type 2 diabetes, and low testosterone levels in men, independent of elevated body adiposity. Cross-sectional findings are augmented by a small number of prospective studies suggesting that a greater degree of hypothalamic inflammation and gliosis may predict adiposity gain and worsening insulin sensitivity in susceptible individuals. In conclusion, existing human studies corroborate a large preclinical literature demonstrating that hypothalamic neuroinflammatory responses play a role in obesity pathogenesis. Extensive or permanent hypothalamic tissue remodeling may negatively affect the function of neuroendocrine regulatory circuits and promote the development and maintenance of elevated body weight in obesity and/or comorbid endocrine disorders.

Very low-calorie ketogenic diet rapidly augments testosterone levels in non-diabetic obese subjects

BACKGROUND

The very low-calorie ketogenic diet (VLCKD) represents an opportunity to attain clinically relevant weight loss in obese patients. Functional hypogonadism represents a frequent hormonal disorder associated with obesity and visceral fat accumulation characterised by low testosterone levels and subnormal luteinising hormone (LH) levels.

AIM

To evaluate the early effects of VLCKD on serum total testosterone (TT) levels in non-diabetic obese patients.

METHODS

Twenty-two obese male patients (mean age 39.3 ± 11.7 years, mean body mass index (BMI) 38.2 ± 6.4 kg/m² ) were enrolled and treated for 28 days with VLCKD. Anthropometric and hormonal variables were assessed before, during and after diet intervention.

RESULTS

After 7 and 28 days on a VLCKD, a significant and persistent reduction in body weight, BMI, fat mass, blood glucose, insulin and homeostasis model assessment index was observed compared with baseline. TT significantly increased after 7 days (+35 ± 64 ng/dl) and 28 days (+74 ± 97 ng/dl) on a VLCKD. In addition to TT, a significant increase in serum sex hormone-binding globulin levels was observed after 7 (+2.1 ± 4.1) and 28 days (+7.7 ± 10.0). However, both calculated free testosterone and LH did not change after 7 or 28 days of VLCKD. Following cessation of VLCKD, hypogonadal subjects achieved a higher percentage of total weight loss (8.5% ± 1.5%), a greater reduction in weight (-9.94 ± 1.66 kg), fat mass (-7 ± 2.1 kg) and waist circumference (-6.31 ± 2.65 cm) and a greater improvement in glycaemia (-8.75 ± 10.92 mg/dl) as compared with eugonadal subjects. Furthermore, hypogonadal subjects exhibited a trend of higher TT increase (+98.12 ± 71.51 ng/dl) as compared with eugonadal subjects.

CONCLUSIONS

VLCKD results in rapid improvements in TT levels associated with weight loss in male obese non-diabetic subjects, particularly in the presence of obesity-related hypogonadism.

Ketogenic state improves testosterone serum levels-results from a systematic review and meta-analysis

BACKGROUND

It is widely demonstrated that obesity and hypogonadism are bi-directionally correlated, since the hypogonadism prevalence is higher in obese population, while weight loss increases testosterone serum levels. Several approaches are available to contrast weight excess, from simple dietary regimens to more complex surgical procedures. Ketogenic diets (KD) fit in this context and their application is growing year after year, aiming to improve the metabolic and weight patterns in obese patients. However, KD influence on testosterone levels is still poorly investigated.

OBJECTIVES

To systematically evaluate the potential effect of KD on testosterone levels.

METHODS

A systematic literature search was performed until April 2022 including studies investigating testosterone levels before and after KD. Secondary endpoints were body weight, estradiol and sex-hormone binding globulin serum levels. Any kind of KD was considered eligible, and no specific criteria for study populations were provided.

RESULTS

Seven studies (including eight trials) were included in the analysis for a total of 230 patients, five using normocaloric KD and three very low calories KD (VLCKD). Only three studies enrolled overweight/obese men. A significant total testosterone increase was recorded after any kind of KD considering 111 patients (2.86 [0.95, 4.77], p = 0.003). This increase was more evident considering VLCKD compared to normocaloric KD (6.75 [3.31, 10.20], p < 0.001, versus 0.98 [0.08, 1.88], p = 0.030). Meta-regression analyses highlighted significant correlations between the post-KD testosterone raise with patients' age (R-squared 36.4, p < 0.001) and weight loss (R-squared 73.6, p < 0.001).

CONCLUSIONS

Comprehensively, KD improved testosterone levels depending on both patients' age and KD-induced weight loss. However, the lack of information in included studies on hormones of the hypothalamic-pituitary-gonadal axis prevents an exhaustive comprehension about mechanisms connecting ketosis and testosterone homeostasis.

Inhibition of nitric oxide synthase or cystathionine gamma-lyase abolishes leptin-induced fever in male rats

Leptin is an adipokine that regulates energy balance and immune function. Peripheral leptin administration elicits prostaglandin E₂-dependent fever in rats. The gasotransmitters nitric oxide (NO) and hydrogen sulfide (H₂S) are also involved in lipopolysaccharide (LPS)-induced fever response. However, there is no data in the literature indicating if these gasotransmitters have a role in leptin-induced fever response. Here, we investigate the inhibition of NO and H₂S enzymes neuronal nitric oxide synthase (nNOS), inducible nitric oxide synthase (iNOS), and cystathionine γ-lyase (CSE) in leptin-induced fever response, respectively. Selective nNOS inhibitor 7-nitroindazole (7-NI), selective iNOS inhibitor aminoguanidine (AG), and CSE inhibitor dl-propargylglycine (PAG) were administered intraperitoneally (ip). Body temperature (Tb), food intake, and body mass were recorded in fasted male rats. Leptin (0.5 mg/kg ip) induced a significant increase in Tb, whereas AG (50 mg/kg ip), 7-NI (10 mg/kg ip), or PAG (50 mg/kg ip) caused no changes in Tb. AG, 7-NI, or PAG abolished leptin increase in Tb. Our results highlight the potential involvement of iNOS, nNOS, and CSE in leptin-induced febrile response without affecting anorexic response to leptin in fasted male rats 24 h after leptin injection. Interestingly, all the inhibitors alone had the same anorexic effect induced by leptin. These findings have implications for understanding the role of NO and H₂S in leptin-induced febrile response.

Mechanism of leptin-NPY on the onset of puberty in male offspring rats after androgen intervention during pregnancy

OBJECTIVES

The time of onset of puberty has been increasingly earlier, but its mechanism is still unclear. This study aimed to reveal the mechanism of leptin and NPY in the onset of puberty in male offspring rats after androgen intervention during pregnancy.

METHODS

Eight-week-old specific pathogen-free (SPF) healthy male Sprague-Dawley (SD) rats and 16 female SD rats were selected and caged at 1:2. The pregnant rats were randomly divided into the olive oil control group (OOG) and testosterone intervention group (TG), with 8 rats in each group. Olive oil and testosterone were injected from the 15th day of pregnancy, for a total of 4 injections (15th, 17th, 19th, 21st day). After the onset of puberty, the male offspring rats were anesthetized with 2% pentobarbital sodium to collect blood by ventral aorta puncture and decapitated to peel off the hypothalamus and abdominal fat. Serum testosterone (T), free testosterone (FT), dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), sex hormone binding globulin (SHBG), and leptin were detected by ELISA, and then the free androgen index (FAI) was calculated. The mRNA levels of androgen receptor (AR), estrogen receptor α (ERα), NPY, leptinR, and NPY2R in the hypothalamus and abdominal fat were detected by RT-PCR. Protein expression levels of AR, ERα, NPY, leptinR, and NPY2R in the arcuate nucleus (ARC) of the hypothalamus were detected by immunohistochemistry.

RESULTS

The time of onset of puberty was significantly earlier in the TG than in the OOG (P< 0.05) and was positively correlated with body weight, body length, abdominal fat, and leptinR mRNA levels in adipose tissue in the OOG (P< 0.05), while it was positively correlated with serum DHT and DHEA concentrations and FAI and AR mRNA levels in the hypothalamus in the TG (P< 0.05). The NPY2R mRNA level and protein expression levels of ERα, NPY2R, and leptinR in the TG were significantly higher than those in the OOG, while the protein expression levels of AR and NPY in the TG were significantly lower than those in the OOG (P< 0.05).

CONCLUSIONS

Testosterone intervention during pregnancy led to an earlier onset of puberty in male offspring rats, which may render the male offspring rats more sensitive to androgens, leptin, and NPY at the onset of puberty.

Epigenetic modifier Kdm6a/Utx controls the specification of hypothalamic neuronal subtypes in a sex-dependent manner

Kdm6a is an X-chromosome-linked H3K27me2/3 demethylase that promotes chromatin accessibility and gene transcription and is critical for tissue/cell-specific differentiation. Previous results showed higher Kdm6a levels in XX than in XY hypothalamic neurons and a female-specific requirement for Kdm6a in mediating increased axogenesis before brain masculinization. Here, we explored the sex-specific role of Kdm6a in the specification of neuronal subtypes in the developing hypothalamus. Hypothalamic neuronal cultures were established from sex-segregated E14 mouse embryos and transfected with siRNAs to knockdown Kdm6a expression (Kdm6a-KD). We evaluated the effect of Kdm6a-KD on Ngn3 expression, a bHLH transcription factor regulating neuronal sub-specification in hypothalamus. Kdm6a-KD decreased Ngn3 expression in females but not in males, abolishing basal sex differences. Then, we analyzed Kdm6a-KD effect on Ascl1, Pomc, Npy, Sf1, Gad1, and Th expression by RT-qPCR. While Kdm6a-KD downregulated Ascl1 in both sexes equally, we found sex-specific effects for Pomc, Npy, and Th. Pomc and Th expressed higher in female than in male neurons, and Kdm6a-KD reduced their levels only in females, while Npy expressed higher in male than in female neurons, and Kdm6a-KD upregulated its expression only in females. Identical results were found by immunofluorescence for Pomc and Npy neuropeptides. Finally, using ChIP-qPCR, we found higher H3K27me3 levels at Ngn3, Pomc, and Npy promoters in male neurons, in line with Kdm6a higher expression and demethylase activity in females. At all three promoters, Kdm6a-KD induced an enrichment of H3K27me3 only in females. These results indicate that Kdm6a plays a sex-specific role in controlling the expression of transcription factors and neuropeptides critical for the differentiation of hypothalamic neuronal populations regulating food intake and energy homeostasis.

Adipose tissue and ovarian aging: Potential mechanism and protective strategies

Ovarian aging occurs approximately 10 years prior to the natural age-associated functional decline of other organ systems. With the increase of life expectancy worldwide, ovarian aging has gradually become a key health problem among women. Therefore, understanding the causes and molecular mechanisms of ovarian aging is very essential for the inhibition of age-related diseases and the promotion of health and longevity in women. Recently, studies have revealed an association between adipose tissue (AT) and ovarian aging. Alterations in the function and quantity of AT have profound consequences on ovarian function because AT is central for follicular development, lipid metabolism, and hormonal regulation. Moreover, the interplay between AT and the ovary is bidirectional, with ovary-derived signals directly affecting AT biology. In this review, we summarize the current knowledge of the complex molecular mechanisms controlling the crosstalk between the AT and ovarian aging, and further discuss how therapeutic targeting of the AT can delay ovarian aging.