Androgens decrease plasma adiponectin, an insulin-sensitizing adipocyte-derived protein

The DNA methyltransferase inhibitor decitabine blunts the response to a high-animal fat and protein diet in mice

Increasing evidence hints that DNA hypermethylation may mediate the pathogenic response to cardiovascular risk factors. Here, we tested a corollary of that hypothesis, that is, that the DNA methyltransferase inhibitor decitabine (Dec) ameliorates the metabolic profile of mice fed a moderately high-animal fat and protein diet (HAFPD), a proxy of cardiovascular risk-associated Western-type diet. HAFPD-fed mice were exposed to Dec or vehicle for eight weeks (8W set, 4-32/group). To assess any memory of past exposure to Dec, we surveyed a second mice set treated as 8W but HAFPD-fed for further eight weeks without any Dec (16W set, 4-20/group). In 8W, Dec markedly reduced HAFPD-induced body weight gain in females, but marginally in males. Characterization of females revealed that Dec augmented skeletal muscle lipid content, while decreasing liver fat content and increasing plasma nonesterified fatty acids, adipose insulin resistance, and-although marginally-whole blood acylcarnitines, compared to HAFPD alone. Skeletal muscle mitochondrial DNA copy number was higher in 8W mice exposed to HAFPD and Dec, or in 16W mice fed HAFPD only, relative to 8W mice fed HAFPD only, but Dec induced a transcriptional profile indicative of ameliorated mitochondrial function. Memory of past Dec exposure was tissue-specific and sensitive to both duration of exposure to HAFPD and age. In conclusion, Dec redirected HAFPD-induced lipid accumulation toward the skeletal muscle, likely due to augmented mitochondrial functionality and increased lipid demand. As caveat, Dec induced adipose insulin resistance. Our findings may help identifying strategies for prevention and treatment of lipid dysmetabolism.

The mysterious association between adiponectin and endometriosis

Adiponectin is a pleiotropic cytokine predominantly derived from adipose tissue. In addition to its role in regulating energy metabolism, adiponectin may also be related to estrogen-dependent diseases, and many studies have confirmed its involvement in mediating diverse biological processes, including apoptosis, autophagy, inflammation, angiogenesis, and fibrosis, all of which are related to the pathogenesis of endometriosis. Although many researchers have reported low levels of adiponectin in patients with endometriosis and suggested that it may serve as a protective factor against the development of the disease. Therefore, the purpose of this review was to provide an up-to-date summary of the roles of adiponectin and its downstream cytokines and signaling pathways in the aforementioned biological processes. Further systematic studies on the molecular and cellular mechanisms of action of adiponectin may provide novel insights into the pathophysiology of endometriosis as well as potential therapeutic targets.

Metabolic hormones are integral regulators of female reproductive health and function

The female reproductive system is strongly influenced by nutrition and energy balance. It is well known that food restriction or energy depletion can induce suppression of reproductive processes, while overnutrition is associated with reproductive dysfunction. However, the intricate mechanisms through which nutritional inputs and metabolic health are integrated into the coordination of reproduction are still being defined. In this review, we describe evidence for essential contributions by hormones that are responsive to food intake or fuel stores. Key metabolic hormones-including insulin, the incretins (glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1), growth hormone, ghrelin, leptin, and adiponectin-signal throughout the hypothalamic-pituitary-gonadal axis to support or suppress reproduction. We synthesize current knowledge on how these multifaceted hormones interact with the brain, pituitary, and ovaries to regulate functioning of the female reproductive system, incorporating in vitro and in vivo data from animal models and humans. Metabolic hormones are involved in orchestrating reproductive processes in healthy states, but some also play a significant role in the pathophysiology or treatment strategies of female reproductive disorders. Further understanding of the complex interrelationships between metabolic health and female reproductive function has important implications for improving women's health overall.

Sex differences in energy metabolism: natural selection, mechanisms and consequences

Metabolic homeostasis operates differently in men and women. This sex asymmetry is the result of evolutionary adaptations that enable women to resist loss of energy stores and protein mass while remaining fertile in times of energy deficit. During starvation or prolonged exercise, women rely on oxidation of lipids, which are a more efficient energy source than carbohydrates, to preserve glucose for neuronal and placental function and spare proteins necessary for organ function. Carbohydrate reliance in men could be an evolutionary adaptation related to defence and hunting, as glucose, unlike lipids, can be used as a fuel for anaerobic high-exertion muscle activity. The larger subcutaneous adipose tissue depots in healthy women than in healthy men provide a mechanism for lipid storage. As female mitochondria have higher functional capacity and greater resistance to oxidative damage than male mitochondria, uniparental inheritance of female mitochondria may reduce the transmission of metabolic disorders. However, in women, starvation resistance and propensity to obesity have evolved in tandem, and the current prevalence of obesity is greater in women than in men. The combination of genetic sex, programming by developmental testosterone in males, and pubertal sex hormones defines sex-specific biological systems in adults that produce phenotypic sex differences in energy homeostasis, metabolic disease and drug responses.

Effect of zinc intake on association between fluoride exposure and abnormal sex steroid hormones among US pubertal males: NHANES, 2013-2016

Excessive fluoride exposure can disturb the balance of sex hormones. Zinc is essential for sex hormone synthesis and spermatogenesis. But it is not clear how zinc affects the relationship of fluoride exposure with abnormal sex steroid hormones. Here, a total of 1008 pubertal males from the National Health and Nutrition Examination Survey (NHANES) in two cycles (2013-2014, 2015-2016) were enrolled. The concentrations of water fluoride and plasma fluoride and the levels of serum testosterone, estradiol, and sex hormone binding globulin (SHBG) were measured. Two 24-h dietary recall interviews were conducted to assess the dietary zinc intake. The relationships of fluoride exposure and zinc intake with sex hormones were examined using linear regression and logistic regression models, while the generalized additive model was used to evaluate their non-linear relationship. Our findings revealed that for every two-fold increase in plasma fluoride concentration, testosterone levels decreased by 7.27% (95% CI - 11.49%, - 2.86%) and estradiol levels decreased by 8.73% (95% CI - 13.61%, - 3.57%). There was also significant non-linear association observed between zinc intake and SHBG levels. Being in the first tertile of plasma fluoride had a 60% lower risk of high SHBG (OR = 0.40, 95% CI 0.18, 0.89) compared with being in the second tertile. When compared to the first tertile, being in the second tertile of zinc intake was associated with a 63% (OR = 0.37, 95% CI 0.14, 0.98) lower risk of high SHBG. Furthermore, we observed an interactive effect between the plasma fluoride and zinc intake on estradiol and SHBG, as well as the risk of high SHBG (P-interaction < 0.10). These findings suggest that fluoride exposure and zinc intake can affect sex steroid hormone levels and the risk of high SHBG. Notably, zinc intake may alleviate the increased risk of high SHBG and the abnormal changes of estradiol and SHBG caused by higher fluoride exposure.

Association of adiponectin gene expression with atrial fibrillation in a Pakistani populace

Adiponectin, an adipocytokine produced and secreted by adipose tissue, has anti-diabetic, anti-atherogenic, and anti-inflammatory properties. This case-control study was aimed to assess the expression and serum levels of adiponectin in subject suffereing from atrial fibrillation (AF). The study's subjects (n = 690) were enrolled from the Punjab Institute of Cardiology, Lahore and were grouped into control, AF without Metabolic syndrome (MetS), and AF with MetS groups. Along with the collection of demographic data, an analysis of adiponectin and biochemical parameters were performed. A highly significant difference in serum levels of adiponectin was observed among the control, AF without MetS, and AF with MetS groups (61.61 ± 45.30 ng/ml, 37.20 ± 19.46 ng/ml, 63.78 ± 61.69 ng/ml). The expression analysis of adiponectin was decreased (n-fold = ̴ 0.30) in AF without MetS group as compared to control group (n-fold =  ~ 1.16) but increased in AF with MetS group (n-fold = ̴ 6.26). The correlation analysis revealed a highly significant positive relationship between the expression of the adiponectin gene with waist-to-hip ratio (WHR) in AF without MetS group. Whereas, serum adiponectin was negatively related to serum triglycerides (TG) in AF with MetS group. In multiple regression analysis using adiponectin expression as the dependent variable, WHR was a determinant in AF without MetS. Whereas, when serum adiponectin was used as the dependent variable, serum TG was the determinant in group AF with MetS. The present study implicates that decreased expression and serum levels of adiponectin were associated with the development of AF in which WHR and serum TG also contributed towards the onset of atrial fibrillation.

An overview on androgen-mediated actions in skeletal muscle and adipose tissue

Androgens are a class of steroid hormones primarily associated with male sexual development and physiology, but exert pleiotropic effects in either sex. They have a crucial role in various physiological processes, including the regulation of skeletal muscle and adipose tissue homeostasis. The effects of androgens are mainly mediated through the androgen receptor (AR), a ligand-activated nuclear receptor expressed in both tissues. In skeletal muscle, androgens via AR exert a multitude of effects, ranging from increased muscle mass and strength, to the regulation of muscle fiber type composition, contraction and metabolic functions. In adipose tissue, androgens influence several processes including proliferation, fat distribution, and metabolism but they display depot-specific and organism-specific effects which differ in certain context. This review further explores the potential mechanisms underlying androgen-AR signaling in skeletal muscle and adipose tissue. Understanding the roles of androgens and their receptor in skeletal muscle and adipose tissue is essential for elucidating their contributions to physiological processes, disease conditions, and potential therapeutic interventions.

Adiponectin inhibits GnRH secretion via activating AMPK and PI3K signaling pathways in chicken hypothalamic neuron cells

It has been reported that adiponectin (AdipoQ), an adipokine secreted by white adipose tissue, plays an important role in the control of animal reproduction in addition to its function in energy homeostasis by binding to its receptors AdipoR1/2. However, the molecular mechanisms of AdipoQ in the regulation of animal reproduction remain elusive. In this study, we investigated the effects of AdipoQ on hypothalamic reproductive hormone (GnRH) secretion and reproduction-related receptor gene (estrogen receptor [ER] and progesterone receptor [PR]) expression in hypothalamic neuronal cells (HNCs) of chickens by using real-time fluorescent quantitative PCR (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), Western blot (WB) and cell counting kit-8 (CCK-8) assays and found that overexpression of AdipoQ could increase the expression levels of AdipoR1/2 and reproduction-related receptor genes (P < 0.05) while decreasing the expression level of GnRH. In contrast, interference with AdipoQ mRNA showed the opposite results in HNCs. Furthermore, we demonstrated that AdipoQ exerts its functions through the AMPK and PI3K signaling pathways. Finally, our in vitro experiments found that AdipoRon (a synthetic substitute for AdipoQ) treatment and AdipoR1/2 RNAi interference co-treatment resulted in no effect on GnRH secretion, suggesting that the inhibition of GnRH secretion by AdipoQ is mediated by the AdipoR1/2 signaling axis. In summary, we uncovered, for the first time, the molecular mechanism of AdipoQ in the regulation of reproductive hormone secretion in hypothalamic neurons in chickens.

Sex Influences the Safety and Therapeutic Efficacy of Cardiac Nanomedicine Technologies

Nanomedicine technologies are being developed for the prevention, diagnosis, and treatment of cardiovascular disease (CVD), which is the leading cause of death worldwide. Before delving into the nuances of cardiac nanomedicine, it is essential to comprehend the fundamental sex-specific differences in cardiovascular health. Traditionally, CVDs have been more prevalent in males, but it is increasingly evident that females also face significant risks, albeit with distinct characteristics. Females tend to develop CVDs at a later age, exhibit different clinical symptoms, and often experience worse outcomes compared to males. These differences indicate the need for sex-specific approaches in cardiac nanomedicine. This Perspective discusses the importance of considering sex in the safety and therapeutic efficacy of nanomedicine approaches for the prevention, diagnosis, and treatment of CVD.

Multifaceted effects of obesity on cancer immunotherapies: Bridging preclinical models and clinical data

Obesity, defined by excessive body fat, is a highly complex condition affecting numerous physiological processes, such as metabolism, proliferation, and cellular homeostasis. These multifaceted effects impact cells and tissues throughout the host, including immune cells as well as cancer biology. Because of the multifaceted nature of obesity, common parameters used to define it (such as body mass index in humans) can be problematic, and more nuanced methods are needed to characterize the pleiotropic metabolic effects of obesity. Obesity is well-accepted as an overall negative prognostic factor for cancer incidence, progression, and outcome. This is in part due to the meta-inflammatory and immunosuppressive effects of obesity. Immunotherapy is increasingly used in cancer therapy, and there are many different types of immunotherapy approaches. The effects of obesity on immunotherapy have only recently been studied with the demonstration of an "obesity paradox", in which some immune therapies have been demonstrated to result in greater efficacy in obese subjects despite the direct adverse effects of obesity and excess body fat acting on the cancer itself. The multifactorial characteristics that influence the effects of obesity (age, sex, lean muscle mass, underlying metabolic conditions and drugs) further confound interpretation of clinical data and necessitate the use of more relevant preclinical models mirroring these variables in the human scenario. Such models will allow for more nuanced mechanistic assessment of how obesity can impact, both positively and negatively, cancer biology, host metabolism, immune regulation, and how these intersecting processes impact the delivery and outcome of cancer immunotherapy.

Is Increasing Diet Diversity of Animal-Source Foods Related to Better Health-Related Quality of Life among Chinese Men and Women?

Diet plays a crucial role in regulating individuals' lifestyles and is closely related to health. The intake of animal-sourced foods (ASF) provides the human body with high-quality protein and various micronutrients. This study aimed to investigate whether the diversity of animal foods has a positive impact on the health-related quality of life (HRQoL) among residents. The data came from the Shaanxi baseline survey of the Northwest Chinese Regional Ethnic Cohort Study, which recruited more than 100 thousand participants aged 35 to 74 from five provinces between June 2018 and May 2019. A total of 39,997 participants in Shaanxi (mean age: 50 years; 64% women) were finally included in this current study. The animal source food diet diversity score (ASFDDS) was established based on the frequency of consuming pork, mutton, beef, poultry, seafood, eggs, pure milk, and yogurt. The physical component score (PCS) and mental component score (MCS), ranging from 0 to 100 on the 12-Item Short Form Survey (SF-12), were used to assess participants' HRQoL. Better PCS/MCS was defined as scores higher than the 90th percentile. The results showed that men had a higher intake of ASF and ASFDDS than women. After adjusting for potential confounders, compared with those who never or rarely consumed animal foods, the likelihood of having better PCS and MCS increased by 16% (OR = 1.16, 95%CI: 1.01-1.34) and 24% (OR = 1.24, 95%CI: 1.03-1.448), respectively, in men with an ASFDDS ≥ 2. In women, a 34% increase (OR = l.34, 95%CI: 116-l.54) likelihood for better PCS was observed for an ASFDDS ≥ 2, but no association was observed for MCS. Increasing each specific animal source's food intake was associated with better PCS after adjusting for all covariates. However, for MCS, positive associations were only observed in seafood consumption among men and eggs among women. Restricted cubic splines showed a substantial dose-response association between intake frequency of animal-source foods and PCS, both in men and women. The study suggests that a diverse intake of animal-sourced foods can potentially improve the HRQoL of Chinese adults.

Adiponectin receptor 1 could explain the sex differences in molecular basis of cognitive improvements induced by exercise training in type 2 diabetic rats

Adipokines dysregulation, the main reason for cognitive impairments (CI) induced by diabetes, shows a sex-dependent pattern inherently and in response to exercise. This study aimed to compare the attenuating effect of 8-week high intensity-interval training (HIIT) on type 2 diabetes (T2D)-induced CI between male and female rats with a special focus on adiponectin and leptin. 28 male & 28 female Wistar rats with an average age of 8 weeks were randomly assigned into four groups: control (Con), exercise (EX), Diabetes (T2D), and Type 2 diabetes + exercise (T2D + Ex). Rats in EX and T2D + EX groups performed HIIT for eight weeks (80-100% Vmax, 4-10 intervals). T2D was induced by 2 months of a high-fat diet and a single dose of STZ (35 mg/kg) administration. Leptin and adiponectin levels in serum were measured along with hippocampal expression of leptin and adiponectin receptors, AMP-activated protein kinase (AMPK), dephosphorylated glycogen synthase kinase-3 beta (Dep-GSK3β), Tau, and beta-amyloid (Aβ). Homeostasis model assessments (HOMAs) and quantitative insulin-sensitivity check index (QUICKI) indices were calculated. Our results showed that following T2D, serum levels of APN, and hippocampal levels of adiponectin receptor 1 (APNR1) were higher and HOMA-IR was lower in female than male rats (P < 0.05). However, after 8 weeks of HIIT, hippocampal levels of APNR1 and AMPK as well as QUICKI were lower and hippocampal levels of GSK, Tau, and Aβ were higher in females compared to male rats (P < 0.05). While the risk of CI following T2D was more in male than female rats HIIT showed a more ameliorating effect in male animals with APN1 as the main player.

Inflammation-Involved Proteins in Blood Serum of Cataract Patients-A Preliminary Study

Approximately 50% of all global blindness is caused by cataract in adults aged ≥50 years. The mechanisms of the disease are most arguably related to a redox imbalance and inflammation; therefore, the aim of the study was to evaluate the processes associated with inflammation in cataract patients. Twenty-four patients aged 22-60 years (62.5% females) participated in the study, with 33 controls aged 28-60 years (66.7% females). Venous blood serum of the subjects was examined for alpha 1-antitrypsin, as well as selected lysosomal enzymes and adipokines. The activities of lysosomal enzymes, as well as the activity of alpha 1-antitrypsin and the concentrations of c-reactive protein and leptin, were similar in the patients versus the controls. The concentrations of interleukin 6 and resistin were lower, in turn, whereas omentin-1 and adiponectin were higher. Moreover, the study revealed the existence of many linear relationships between the parameters, including multiple linear regression, especially gender-wise. No systemic inflammation was probably noted in the cataract patients tested; nevertheless, the deregulation of adiponectin, omentin-1 and resistin secretion was observed.

Gender Differences in the Pathogenesis and Risk Factors of Hepatocellular Carcinoma

Several chronic liver diseases are characterized by a clear gender disparity. Among them, hepatocellular carcinoma (HCC) shows significantly higher incidence rates in men than in women. The different epidemiological distribution of risk factors for liver disease and HCC only partially accounts for these gender differences. In fact, the liver is an organ with recognized sexual dysmorphism and is extremely sensitive to the action of androgens and estrogens. Sex hormones act by modulating the risk of developing HCC and influencing its aggressiveness, response to treatments, and prognosis. Furthermore, androgens and estrogens are able to modulate the action of other factors and cofactors of liver damage (e.g., chronic HBV infection, obesity), significantly influencing their carcinogenic power. The purpose of this review is to examine the factors related to the different gender distribution in the incidence of HCC as well as the pathophysiological mechanisms involved, with particular reference to the central role played by sex hormones.

Impact of puberty, sex determinants and chronic inflammation on cardiovascular risk in young people

Worrying trends of increased cardiovascular disease (CVD) risk in children, adolescents and young people in the Modern Era have channelled research and public health strategies to tackle this growing epidemic. However, there are still controversies related to the dynamic of the impact of sex, age and puberty on this risk and on cardiovascular health outcomes later in life. In this comprehensive review of current literature, we examine the relationship between puberty, sex determinants and various traditional CVD-risk factors, as well as subclinical atherosclerosis in young people in general population. In addition, we evaluate the role of chronic inflammation, sex hormone therapy and health-risk behaviours on augmenting traditional CVD-risk factors and health outcomes, ultimately aiming to determine whether tailored management strategies for this age group are justified.

Immunological and Metabolic Causes of Infertility in Polycystic Ovary Syndrome

Infertility has been recognized as a civilizational disease. One of the most common causes of infertility is polycystic ovary syndrome (PCOS). Closely interrelated immunometabolic mechanisms underlie the development of this complex syndrome and lead to infertility. The direct cause of infertility in PCOS is ovulation and implantation disorders caused by low-grade inflammation of ovarian tissue and endometrium which, in turn, result from immune and metabolic system disorders. The systemic immune response, in particular the inflammatory response, in conjunction with metabolic disorders, insulin resistance (IR), hyperadrenalism, insufficient secretion of progesterone, and oxidative stress lead not only to cardiovascular diseases, cancer, autoimmunity, and lipid metabolism disorders but also to infertility. Depending on the genetic and environmental conditions as well as certain cultural factors, some diseases may occur immediately, while others may become apparent years after an infertility diagnosis. Each of them alone can be a significant factor contributing to the development of PCOS and infertility. Further research will allow clinical management protocols to be established for PCOS patients experiencing infertility so that a targeted therapy approach can be applied to the factor underlying and driving the "vicious circle" alongside symptomatic treatment and ovulation stimulation. Hence, therapy of fertility for PCOS should be conducted by interdisciplinary teams of specialists as an in-depth understanding of the molecular relationships and clinical implications between the immunological and metabolic factors that trigger reproductive system disorders is necessary to restore the physiology and homeostasis of the body and, thus, fertility, among PCOS patients.

Adiponectin reverses β-Cell damage and impaired insulin secretion induced by obesity

Obesity significantly decreases life expectancy and increases the incidence of age-related dysfunctions, including β-cell dysregulation leading to inadequate insulin secretion. Here, we show that diluted plasma from obese human donors acutely impairs β-cell integrity and insulin secretion relative to plasma from lean subjects. Similar results were observed with diluted sera from obese rats fed ad libitum, when compared to sera from lean, calorically restricted, animals. The damaging effects of obese circulating factors on β-cells occurs in the absence of nutrient overload, and mechanistically involves mitochondrial dysfunction, limiting glucose-supported oxidative phosphorylation and ATP production. We demonstrate that increased levels of adiponectin, as found in lean plasma, are the protective characteristic preserving β-cell function; indeed, sera from adiponectin knockout mice limits β-cell metabolic fluxes relative to controls. Furthermore, oxidative phosphorylation and glucose-sensitive insulin secretion, which are completely abrogated in the absence of this hormone, are restored by the presence of adiponectin alone, surprisingly even in the absence of other serological components, for both the insulin-secreting INS1 cell line and primary islets. The addition of adiponectin to cells treated with plasma from obese donors completely restored β-cell functional integrity, indicating the lack of this hormone was causative of the dysfunction. Overall, our results demonstrate that low circulating adiponectin is a key damaging element for β-cells, and suggest strong therapeutic potential for the modulation of the adiponectin signaling pathway in the prevention of age-related β-cell dysfunction.

Sex differences in glycolipidic disorders after exposure to maternal hyperglycemia during early development

PURPOSE

The aim of this review was to summarize sex differences in glycolipid metabolic phenotypes of human and animal models after exposure to maternal hyperglycemia and overview the underlying mechanisms, providing a new perspective on the maternal hyperglycemia-triggered risk of glycolipidic disorders in offspring.

METHODS

A comprehensive literature search within PubMed was performed. Selected publications related to studies on offspring exposed to maternal hyperglycemia investigating the sex differences of glycolipid metabolism were reviewed.

RESULTS

Maternal hyperglycemia increases the risk of glycolipid metabolic disorders in offspring, such as obesity, glucose intolerance and diabetes. Whether with or without intervention, metabolic phenotypes have been shown to exhibit sex differences between male and female offspring in response to maternal hyperglycemia, which may be related to gonadal hormones, organic intrinsic differences, placenta, and epigenetic modifications.

CONCLUSION

Sex may play a role in the different incidences and pathogenesis of abnormal glycolipid metabolism. More studies investigating both sexes are needed to understand how and why environmental conditions in early life affect long-term health between male and female individuals.

Adiponectin Enhances Fatty Acid Signaling in Human Taste Cells by Increasing Surface Expression of CD36

Adiponectin, a key metabolic hormone, is secreted into the circulation by fat cells where it enhances insulin sensitivity and stimulates glucose and fatty acid metabolism. Adiponectin receptors are highly expressed in the taste system; however, their effects and mechanisms of action in the modulation of gustatory function remain unclear. We utilized an immortalized human fungiform taste cell line (HuFF) to investigate the effect of AdipoRon, an adiponectin receptor agonist, on fatty acid-induced calcium responses. We showed that the fat taste receptors (CD36 and GPR120) and taste signaling molecules (Gα-gust, PLCβ2, and TRPM5) were expressed in HuFF cells. Calcium imaging studies showed that linoleic acid induced a dose-dependent calcium response in HuFF cells, and it was significantly reduced by the antagonists of CD36, GPR120, PLCβ2, and TRPM5. AdipoRon administration enhanced HuFF cell responses to fatty acids but not to a mixture of sweet, bitter, and umami tastants. This enhancement was inhibited by an irreversible CD36 antagonist and by an AMPK inhibitor but was not affected by a GPR120 antagonist. AdipoRon increased the phosphorylation of AMPK and the translocation of CD36 to the cell surface, which was eliminated by blocking AMPK. These results indicate that AdipoRon acts to increase cell surface CD36 in HuFF cells to selectively enhance their responses to fatty acids. This, in turn, is consistent with the ability of adiponectin receptor activity to alter taste cues associated with dietary fat intake.

Tissue-Specific Sex Difference in Mouse Eye and Brain Metabolome Under Fed and Fasted States

Purpose

Visual physiology and various ocular diseases demonstrate sexual dimorphisms; however, how sex influences metabolism in different eye tissues remains undetermined. This study aims to address common and tissue-specific sex differences in metabolism in the retina, RPE, lens, and brain under fed and fasted conditions.

Methods

After ad libitum fed or being deprived of food for 18 hours, mouse eye tissues (retina, RPE/choroid, and lens), brain, and plasma were harvested for targeted metabolomics. The data were analyzed with both partial least squares-discriminant analysis and volcano plot analysis.

Results

Among 133 metabolites that cover major metabolic pathways, we found 9 to 45 metabolites that are sex different in different tissues under the fed state and 6 to 18 metabolites under the fasted state. Among these sex-different metabolites, 33 were changed in 2 or more tissues, and 64 were tissue specific. Pantothenic acid, hypotaurine, and 4-hydroxyproline were the top commonly changed metabolites. The lens and the retina had the most tissue-specific, sex-different metabolites enriched in the metabolism of amino acid, nucleotide, lipids, and tricarboxylic acid cycle. The lens and the brain had more similar sex-different metabolites than other ocular tissues. The female RPE and female brain were more sensitive to fasting with more decreased metabolites in amino acid metabolism, tricarboxylic acid cycles, and glycolysis. The plasma had the fewest sex-different metabolites, with very few overlapping changes with tissues.

Conclusions

Sex has a strong influence on eye and brain metabolism in tissue-specific and metabolic state-specific manners. Our findings may implicate the sexual dimorphisms in eye physiology and susceptibility to ocular diseases.

Estrogens in Adipose Tissue Physiology and Obesity-Related Dysfunction

Menopause-related decline in estrogen levels is accompanied by a change in adipose tissue distribution from a gynoid to an android and an increased prevalence of obesity in women. These unfavorable phenomena can be partially restored by hormone replacement therapy, suggesting a significant role for estrogen in the regulation of adipocytes' function. Indeed, preclinical studies proved the involvement of these hormones in adipose tissue development, metabolism, and inflammatory activity. However, the relationship between estrogen and obesity is bidirectional. On the one hand-their deficiency leads to excessive fat accumulation and impairs adipocyte function, on the other-adipose tissue of obese individuals is characterized by altered expression of estrogen receptors and key enzymes involved in their synthesis. This narrative review aims to summarize the role of estrogen in adipose tissue development, physiology, and in obesity-related dysfunction. Firstly, the estrogen classification, synthesis, and modes of action are presented. Next, their role in regulating adipogenesis and adipose tissue activity in health and the course of obesity is described. Finally, the potential therapeutic applications of estrogen and its derivates in obesity treatment are discussed.

Sex differences in hearing impairment due to diet-induced obesity in CBA/Ca mice

BACKGROUND

Obesity is an independent risk factor for hearing loss. Although attention has focused on major obesity comorbidities such as cardiovascular disease, stroke, and type 2 diabetes, the impact of obesity on sensorineural organs, including the auditory system, is unclear. Using a high-fat diet (HFD)-induced obese mouse model, we investigated the impact of diet-induced obesity on sexual dimorphism in metabolic alterations and hearing sensitivity.

METHODS

Male and female CBA/Ca mice were randomly assigned to three diet groups and fed, from weaning (at 28 days) to 14 weeks of age, a sucrose-matched control diet (10 kcal% fat content diet), or one of two HFDs (45 or 60 kcal% fat content diets). Auditory sensitivity was evaluated based on the auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), and ABR wave 1 amplitude at 14 weeks of age, followed by biochemical analyses.

RESULTS

We found significant sexual dimorphism in HFD-induced metabolic alterations and obesity-related hearing loss. Male mice exhibited greater weight gain, hyperglycemia, increased ABR thresholds at low frequencies, elevated DPOAE, and lower ABR wave 1 amplitude compared to female mice. The hair cell (HC) ribbon synapse (CtBP2) puncta showed significant sex differences. The serum concentration of adiponectin, an otoprotective adipokine, was significantly higher in female than in male mice; cochlear adiponectin levels were elevated by HFD in female but not male mice. Adiponectin receptor 1 (AdipoR1) was widely expressed in the inner ear, and cochlear AdipoR1 protein levels were increased by HFD, in female but not male mice. Stress granules (G3BP1) were significantly induced by the HFD in both sexes; conversely, inflammatory (IL-1β) responses were observed only in the male liver and cochlea, consistent with phenotype HFD-induced obesity.

CONCLUSIONS

Female mice are more resistant to the negative effects of an HFD on body weight, metabolism, and hearing. Females showed increased peripheral and intra-cochlear adiponectin and AdipoR1 levels, and HC ribbon synapses. These changes may mediate resistance to HFD-induced hearing loss seen in female mice.

Alterations in metabolic status of healthy individuals with and without obesity during transition from adolescence to young adulthood

Aim: Extensive research is carried out throughout the world in healthy persons with obesity phenotype in concern with prevalence, metabolic profiling, etc. To the best of the authors’ knowledge, not many studies have investigated the status of adiponectin, specific inflammatory changes, oxidative damage in healthy adolescents and young adults with obesity. Present study was undertaken in adolescents and young adults of urban population in a district of North Karnataka, India, in a view to understand relationship between hormone adiponectin, oxidative stress markers like C3, C4, high sensitivity C-reactive protein (hs-CRP) in non-hypertensive, non-diabetic, euthyroid individuals with and without obesity. Methods: Participant selection was done using cluster sampling technique. Participating adolescents and young adults, each with and without obesity were included in the study. Screening of participants for diabetes, hypertension, and thyroid disorders was done, their serum level of adiponectin, hs-CRP, C3, C4, ceruloplasmin (Cp), thiobarbituric acid reactive substances (TBARS), and total antioxidant capacity (TAC) were estimated using standardized methods in National Accreditation Board for Testing and Calibration Laboratories (NABL) laboratory. Results: Adiponectin (young adults lower than adolescents, P = 0.01) levels were low, while hs-CRP and Cp (young adults higher than adolescents, P = 0.01) levels were high with increasing age in non-obese. While in persons having obesity, aging adiponectin levels were low while hs-CRP, C3, Cp levels were high significantly. Females without obesity had significantly higher values of C3 than males. Adiponectin showed higher levels in females than males, however, statistical significance could not be achieved (P = 0.308). While females with obesity, exhibited statistically lower levels of adiponectin, and higher levels of C3 and C4. Conclusions: Being non-diabetic and non-hypertensive yet obese, tagged by one time of assay, does not suffice to be categorized as healthy. Healthy young adults with obesity are exhibiting lower levels of adiponectin and higher levels of inflammatory and oxidative stress markers compared to adolescents with obesity. This implies, the so categorized “healthy obese” participants are in a phase of transition towards an unhealthy state.

Growth differentiation factor-15/adiponectin ratio as a potential biomarker for metabolic syndrome in Han Chinese

Aims

Growth differentiation factor-15 (GDF-15) and adiponectin are adipokines that regulate metabolism. This study aimed to evaluate the roles of GDF-15, adiponectin, and GDF-15/adiponectin ratio (G/A ratio) as biomarkers for detecting metabolic syndrome (MS).

Materials and methods

This cross-sectional study included 676 participants aged 20-70 years in Jurong, China. The participants were divided into four groups based on sex and age (<40 and ≥40 years). MS was defined according to the modified National Cholesterol Education Program Adult Treatment Panel III criteria. Receiver operating characteristic curves were used to evaluate the performance of GDF-15, adiponectin, and the G/A ratio in predicting MS.

Results

The prevalence of MS was 22.0% (149/676). Logistic regression analysis indicated that the G/A ratio and adiponectin levels, but not GDF-15 levels, were correlated with MS [odds ratio; 95% CI 1.010 (1.006-1.013) and 0.798 (0.735-0.865), respectively] after adjusting for confounding factors. The G/A ratio displayed a significant relationship with MS in each subgroup and with each MS component in both men and women; however, adiponectin concentrations were significantly associated with MS and all its components only in men (all P <0.05). The area under the curve (AUC) of the G/A ratio and the adiponectin level for MS was 0.758 and 0.748, respectively. The highest AUC was 0.757 for the adiponectin level in men and 0.724 for the G/A ratio in women.

Conclusions

This study suggests that the G/A ratio and adiponectin are potential biomarkers for detecting MS in women and men, respectively.

Age-dependent sex difference of non-alcoholic fatty liver disease in TSOD and db/db mice

According to previous clinical studies, the prevalence of non-alcoholic fatty liver disease (NAFLD) is higher in men than women only during the reproductive age. Animal models of NAFLD that reflect sex differences in humans have not been established. In this study, we examined sex differences in the hepatic lesions of Tsumura Suzuki obese diabetes (TSOD) and db/db mice, which are representative genetic models of NAFLD. Male and female TSOD and db/db mice were fed with a normal diet and tap water ad libitum. Six male and female mice of each strain were sacrificed at the ages of 3 and 9 months, respectively, and serum biochemical, pathological, and molecular analyses were performed. Serum aspartate aminotransferase (AST) levels were significantly higher in male than female mice of both strains at the age of 3 months; however, at 9 months, significant sex differences were not observed. Similarly, alanine aminotransferase (ALT) levels were significantly higher in male mice than in female TSOD mice at the age of 3 months; however, at 9 months, significant sex differences were not observed. Image analysis of histological slides revealed that the frequency of the steatotic area was significantly higher in male than female db/db mice at the age of 3 months; however, significant sex differences were not observed at 9 months. The frequency of Sirius red-positive fibrotic area was significantly higher in male than female mice in both strains at the age of 3 months; however, significant sex differences were not observed at 9 months. Serum AST and ALT levels and hepatic steatosis and fibrosis in TSOD and db/db mice showed age-dependent sex differences consistent with those observed in human NAFLD. These mice may be suitable for studying sex differences of the disease.

Rho-kinase inhibition ameliorates non-alcoholic fatty liver disease in type 2 diabetic rats

Non-alcoholic fatty liver disease (NAFLD) is linked to type 2 diabetes mellitus (T2DM), obesity, and insulin resistance. The Rho/ROCK pathway had been involved in the pathophysiology of diabetic complications. This study was designed to assess the possible protective impacts of the Rho/Rho-associated coiled-coil containing protein kinase (Rho/ROCK) inhibitor fasudil against NAFLD in T2DM rats trying to elucidate the underlying mechanisms. Animals were assigned into control rats, non-treated diabetic rats with NAFLD, and diabetic rats with NAFLD that received fasudil treatment (10 mg/kg per day) for 6 weeks. The anthropometric measures and biochemical analyses were performed to assess metabolic and liver function changes. The inflammatory and oxidative stress markers and the histopathology of rat liver tissues were also investigated. Groups with T2DM showed increased body weight, serum glucose, and insulin resistance. They exhibited disturbed lipid profile, enhancement of inflammatory cytokines, and deterioration of liver function. Fasudil administration reduced body weight, insulin resistance, and raised liver enzymes. It improved the disturbed lipid profile and attenuated liver inflammation. Moreover, it slowed down the progression of high fat diet (HFD)-induced liver injury and reduced the caspase-3 expression. The present study demonstrated beneficial amelioration effect of fasudil on NAFLD in T2DM. The mechanisms underlying these impacts are improving dyslipidemia, attenuating oxidative stress, downregulated inflammation, improving mitochondrial architecture, and inhibiting apoptosis.

Adipose and Skeletal Muscle Expression of Adiponectin and Liver Receptor Homolog-1 With Weight Loss and Aerobic Exercise

Context

Adiponectin is an adipokine mainly secreted by adipocytes that regulates the metabolism of lipids and glucose. Liver receptor homolog-1 (LRH-1), also named NR5A2, is a nuclear receptor that regulates lipid metabolism and homeostasis.

Objective

The purpose of this study was to compare adiponectin and LRH-1 messenger RNA (mRNA) expression in adipose tissue and LRH-1 expression in skeletal muscle between men and women at baseline and to study the effects of aerobic exercise (AEX) training or weight loss (WL) on their expression.

Methods

This hospital and university setting study included 62 overweight and obese men (n = 23) and women (n = 39) older than 45 years, of whom 41 completed 6 months of WL (n = 21) or AEX (n = 20). Outcomes included abdominal and gluteal adipose tissue and skeletal muscle gene expression.

Results

Adiponectin and LRH-1 mRNA expression in adipose tissue and LRH-1 mRNA expression in skeletal muscle is higher in women than in men (P < .05). Adiponectin mRNA expression in gluteal and abdominal adipose tissue did not change significantly after AEX or WL. LRH-1 mRNA expression increased both in adipose tissue and skeletal muscle after AEX (P < .05) and the change in muscle LRH-1 was different between the groups (P < .05). Adiponectin was positively correlated to LRH-1 in adipose tissue (P < .001). The change in maximal oxygen consumption related to the change in LRH-1 mRNA (r = 0.43; P = .01).

Conclusion

LRH-1, as a nuclear reporter, may activate adiponectin mRNA expression in adipose tissue and increases after AEX.

The role of the androgen receptor in the pathogenesis of obesity and its utility as a target for obesity treatments

Obesity is associated with hypothalamic-pituitary-testicular axis dysregulation in males. Here, we summarize recent evidence derived from clinical trials and studies in preclinical animal models regarding the role of androgen receptor (AR) signaling in the pathophysiology of males with obesity. We also discuss therapeutic strategies targeting the AR for the treatment of obesity and their limitations and provide insight into the future research necessary to advance this field.

The Regulation of Adipose Tissue Health by Estrogens

Obesity and its' associated metabolic diseases such as type 2 diabetes and cardiometabolic disorders are significant health problems confronting many countries. A major driver for developing obesity and metabolic dysfunction is the uncontrolled expansion of white adipose tissue (WAT). Specifically, the pathophysiological expansion of visceral WAT is often associated with metabolic dysfunction due to changes in adipokine secretion profiles, reduced vascularization, increased fibrosis, and enrichment of pro-inflammatory immune cells. A critical determinate of body fat distribution and WAT health is the sex steroid estrogen. The bioavailability of estrogen appears to favor metabolically healthy subcutaneous fat over visceral fat growth while protecting against changes in metabolic dysfunction. Our review will focus on the role of estrogen on body fat partitioning, WAT homeostasis, adipogenesis, adipocyte progenitor cell (APC) function, and thermogenesis to control WAT health and systemic metabolism.

Metabolic and Nutritional Aspects in Paediatric Patients with Klinefelter Syndrome: A Narrative Review

Klinefelter syndrome is the most common sex chromosomal aneuploidy in males. It is well known that patients with this syndrome have greater mortality and morbidity compared to the general population due to cardiovascular diseases and endocrine metabolism disorders. This augmented risk is due both to hypogonadism and to the syndrome itself. Therefore, correct hormonal replacement therapy and early primary prevention are crucial to these patients. Even though different studies are available on this topic in adult patients, only a few authors have focused on the paediatric population. Thus, in this narrative review, we report the current knowledge of metabolic and nutritional aspects in children with Klinefelter syndrome.

Adipose Tissue Secretion Pattern Influences β-Cell Wellness in the Transition from Obesity to Type 2 Diabetes

The dysregulation of the β-cell functional mass, which is a reduction in the number of β-cells and their ability to secure adequate insulin secretion, represents a key mechanistic factor leading to the onset of type 2 diabetes (T2D). Obesity is recognised as a leading cause of β-cell loss and dysfunction and a risk factor for T2D. The natural history of β-cell failure in obesity-induced T2D can be divided into three steps: (1) β-cell compensatory hyperplasia and insulin hypersecretion, (2) insulin secretory dysfunction, and (3) loss of β-cell mass. Adipose tissue (AT) secretes many hormones/cytokines (adipokines) and fatty acids that can directly influence β-cell function and viability. As this secretory pattern is altered in obese and diabetic patients, it is expected that the cross-talk between AT and pancreatic β-cells could drive the maintenance of the β-cell integrity under physiological conditions and contribute to the reduction in the β-cell functional mass in a dysmetabolic state. In the current review, we summarise the evidence of the ability of the AT secretome to influence each step of β-cell failure, and attempt to draw a timeline of the alterations in the adipokine secretion pattern in the transition from obesity to T2D that reflects the progressive deterioration of the β-cell functional mass.

Prepubertal androgen signaling is required to establish male fat distribution

Fat distribution is sexually dimorphic and is associated with metabolic disease risk. It is unknown if prepubertal sex-hormone signaling influences adult fat distribution. Here, we show that karyotypically male androgen-insensitive mice exhibit pronounced subcutaneous adiposity compared with wild-type males and females. This subcutaneous adipose bias emerges prior to puberty and is not due to differences in adipocyte size or rates of adipogenesis between visceral and subcutaneous fat. Instead, we find that androgen-insensitive mice lack an adequate progenitor pool for normal visceral-fat expansion during development, thus increasing the subcutaneous-to-visceral-fat ratio. Obesogenic visceral-fat expansion is likewise inhibited in these mice, yet their metabolic health is similar to wild-type animals with comparable total fat mass. Taken together, these data show that adult fat distribution can be determined prior to the onset of puberty by the relative number of progenitors that seed nascent adipose depots.

Sex differences in regional adipose tissue depots pose different threats for the development of Type 2 diabetes in males and females

Type 2 diabetes mellitus (T2DM) affects males and females disproportionately. In midlife, more males have T2DM than females. The sex difference in T2DM prevalence is, in part, explained by differences in regional adipose tissue characteristics. With obesity, changes to regional adipokine and cytokine release increases the risk of T2DM in both males and females with males having greater levels of TNFα and females having greater levels of leptin, CRP, and adiponectin. Regional immune cell infiltration appears to be pathogenic in both sexes via different routes as males with obesity have greater VAT ATM and a decrease in the protective Treg cells, whereas females have greater SAT ATM and T cells. Lastly, the ability of female adipose tissue to expand all regions through hyperplasia, rather than hypertrophy, protects them against the development of large insulin-resistant adipocytes that dominate male adipose tissue. The objective of this review is to discuss how sex may affect regional differences in adipose tissue characteristics and how these differences may distinguish the development of T2DM in males and females. In doing so, we will show that the origins of T2DM development differ between males and females.

Low serum 25-hydroxyvitamin D level is associated with obesity and atherogenesis in adolescent boys

PURPOSE

We investigated the relationship of 25-hydroxyvitamin D (25[OH]D) level with obesity and atherosclerosis in Japanese adolescents.

METHODS

We examined 492 children (247 boys and 245 girls) aged 12-13 years. The serum 25(OH)D level was compared among underweight, healthy weight, and overweight children. Spearman correlation coefficient analysis was performed to examine the relationships between the 25(OH)D level and body mass index (BMI), plasma lipids, and blood pressure and to compare the latter between the normal (≥20 ng/mL) and low (<20 ng/mL) 25(OH)D groups. Further, we performed a multiple regression analysis to assess the effect on the 25(OH)D level.

RESULTS

The serum 25(OH)D level was significantly lower in overweight (20.5±2.7 ng/mL) than in healthy-weight boys (22.4±3.3 ng/mL) (P=0.004). Spearman correlation coefficients comparing the relationship of the 25(OH)D level with BMI, high-density lipoprotein cholesterol (HDL-C), and atherogenic index indicated significance in boys (ρ=-0.238 [P<0.0001], ρ=0.197 [P=0.002], and ρ=-0.146 [P=0.022], respectively). In boys, the multiple regression analysis results showed that BMI had negative and HDL-C had positive effects on the 25(OH)D level. The first was higher and the latter was lower in boys with low 25(OH)D level than in those with normal levels, respectively (P<0.05). No significant correlations were detected in girls.

CONCLUSION

Low serum 25(OH)D level was associated with obesity and increased atherogenic risk in adolescent boys only. This sex difference was probably mediated by body composition, sun exposure, estrogen, and adiponectin, which are characteristics of puberty.

Preliminary Study on Risk Factors for Morbidity of Nonalcoholic Fatty Liver Disease in High-Income Male Population

OBJECTIVES

Believed to be a result of metabolic syndrome and unhealthy lifestyle, the incidence of nonalcoholic fatty liver disease (NAFLD) has become a serious public health problem. Among the high-income male population, metabolic syndrome and unhealthy lifestyle are particularly prominent. Therefore, we conducted a survey on 375 high-income male subjects, expecting to understand the risk factors and related factors for morbidity of NAFLD among the high-income male population being physically examined in Shanghai.

METHODS

A cross-sectional study was applied to 375 high-income male subjects (including 190 patients with NAFLD and 185 non-NAFLD subjects) who were examined in the special needs clinic at Huadong Hospital affiliated to Fudan University. In combination with medical history, physical examination, and laboratory test results and by use of a self-made NAFLD health questionnaire, the basic data of the research objects were collected and the obtained data were subject to a correlation analysis.

RESULTS

This study investigated 375 high-income males, and the morbidity rate of NAFLD was 50.67%. The NAFLD group was higher than the non-NAFLD group in terms of body weight, BMI, systolic blood pressure, and diastolic blood pressure (P < 0.05). Hypertension (OR = 2.944), diabetes (OR = 7.278), and hyperuricemia (OR = 1.922) are the risk factors for NAFLD; compared with no metabolic diseases, one (OR = 1.848), two (OR = 2.417), and three metabolic diseases (OR = 14.788) are risk factors for the development of NAFLD. Compared with the non-NAFLD group, the NAFLD group had a higher level of WBC, RBC, Hb, PLT, FPG, HbA1c, ALT, AST, GGT, ALP, TP, and UA (P < 0.05). There was a statistically significant difference in the intake of supper and staple foods between the NAFLD group and the non-NAFLD group, and the highly greasy diet was a risk factor for NAFLD (OR = 2.173) as opposed to the nongreasy diet.

CONCLUSION

High-income male population is a high-risk group of NAFLD. Most of the patients with NAFLD have abnormal biochemical indicators as opposed to the healthy population and are more likely to be complicated with other chronic diseases or abnormal health status. And the occurrence of hypertension, diabetes, and hyperuricemia is the risk factor for the development of NAFLD. At the same time, the number of metabolic diseases complicated is also a risk factor for NAFLD as compared with the absence of complications with such metabolic diseases. Compared with a diet that is not greasy, the fact that high-income male NAFLD patients have a very greasy diet increases the risk of NAFLD.

Sexual Dimorphism in Cardiovascular Biomarkers: Clinical and Research Implications

Sex-based differences in cardiovascular disease presentation, diagnosis, and response to therapies are well established, but mechanistic understanding and translation to clinical applications are limited. Blood-based biomarkers have become an important tool for interrogating biologic pathways. Understanding sexual dimorphism in the relationship between biomarkers and cardiovascular disease will enhance our insights into cardiovascular disease pathogenesis in women, with potential to translate to improved individualized care for men and women with or at risk for cardiovascular disease. In this review, we examine how biologic sex associates with differential levels of blood-based biomarkers and influences the effect of biomarkers on disease outcomes. We further summarize key differences in blood-based cardiovascular biomarkers along central biologic pathways, including myocardial stretch/injury, inflammation, adipose tissue metabolism, and fibrosis pathways in men versus women. Finally, we present recommendations for leveraging our current knowledge of sex differences in blood-based biomarkers for future research and clinical innovation.

Large-for-Gestational-Age, Leptin, and Adiponectin in Infancy

CONTEXT

Fetal overgrowth "programs" an elevated risk of obesity and type 2 diabetes in adulthood. Plausibly, adipokines may be involved in programming metabolic health.

OBJECTIVE

This work aimed to evaluate whether large-for-gestational-age (LGA), an indicator of fetal overgrowth, is associated with altered circulating leptin and adiponectin levels in infancy, and assess the determinants.

METHODS

In the Canadian 3D birth cohort, we studied 70 LGA (birth weight > 90th percentile) and 140 optimal-for-gestational-age (OGA, 25th-75th percentiles) infants matched by maternal ethnicity, smoking, and gestational age at delivery. The primary outcomes were fasting leptin, and total and high-molecular-weight (HMW) adiponectin concentrations at age 2 years.

RESULTS

LGA infants had higher body mass index (BMI) than OGA infants. However, there were no significant differences in leptin, and total and HMW adiponectin concentrations. Leptin concentrations were positively associated with female sex, weight (z score) gain 0 to 24 months, current BMI, and the sum of triceps and subscapular skinfold thickness, and negatively associated with maternal age and White ethnicity. Female sex was associated with lower total and HMW adiponectin concentrations. Weight (z score) gain 0 to 24 months and current BMI were positively correlated with total and HMW adiponectin concentrations in LGA infants only.

CONCLUSION

This study is the first to demonstrate that LGA does not matter for circulating leptin and adiponectin concentrations in infancy, and there may be LGA-specific positive associations between weight gain or current BMI and adiponectin concentrations in infancy, suggesting dysfunction in establishing the adiposity-adiponectin negative feedback loop in LGA individuals.

Estradiol overcomes adiponectin-resistance in diabetic mice by regulating skeletal muscle adiponectin receptor 1 expression

Adiponectin and insulin resistance creates a vicious cycle that exacerbates type 2 diabetes. Earlier, we observed that female leptin receptor-deficient BLKS mice (BKS-db/db) were more sensitive to an adiponectin mimetic GTDF than males, which led us to explore if E2 plays a crucial role in modulation of adiponectin-sensitivity. Male but not female BKS-db/db mice were resistant to metabolic effects of globular adiponectin treatment. Male BKS-db/db displayed reduced skeletal muscle AdipoR1 protein expression, which was consequent to elevated polypyrimidine tract binding protein 1 (PTB) and miR-221. E2 treatment in male BKS-db/db, and ovariectomized BALB/c mice rescued AdipoR1 protein expression via downregulation of PTB and miR-221, and also directly increased AdipoR1 mRNA by its classical nuclear receptors. Estrogen receptor regulation via dietary or pharmacological interventions may improve adiponectin resistance and consequently ameliorate insulin resistance in type 2 diabetes.

Association between egg consumption and metabolic syndrome in Chinese population: a cross-sectional study

OBJECTIVES

Metabolic syndrome (MS) comprises a constellation of symptoms that include abdominal obesity, hypertension, hyperglycaemia and dyslipidaemia. Dietary intake is a crucial environmental risk factor for MS, but the exact association between MS and egg consumption, which accounts for more than half of the daily total cholesterol intake in Chinese population, has not been previously studied. The aim of this study was to examine the correlation between dietary egg consumption and the prevalence of MS in the context of a large population.

DESIGN

A cross-sectional study.

SETTINGS

Our study was conducted in a health examination centre in China.

PARTICIPANTS

Participants who aged ≥40 years and received routine physical examinations were included for analyses.

MAIN OUTCOME MEASURES

MS was diagnosed in accordance with the clinical diagnosis criteria specified in the American Heart Association Guidelines. Egg consumption was assessed by a validated semi-quantitative food frequency questionnaire.

RESULTS

A total of 11 529 participants (46.2% women) were included in the present study. On the basis of multivariable logistic regression analysis, egg consumption was negatively associated with the prevalence of MS after adjusting for dietary energy intake (OR=0.84, 95% CI 0.76 to 0.93, p value for trend=0.001). The above findings did not change with further adjustment for other potential confounders: model 2 was further adjusted for age, body mass index and sex (based on model 1) and model 3 was further adjusted for education level, physical activity level, smoking status, alcohol use status, dietary fat intake, dietary fibre intake and nutritional supplementation (based on model 2). Consistent results were obtained from the analysis in the female subgroup but not in male subjects.

CONCLUSIONS

A higher level of egg consumption was associated with a lower prevalence of MS in our study participants, and particularly in female subjects.

Sexual dimorphism in glucose metabolism is shaped by androgen-driven gut microbiome

Males are generally more susceptible to impaired glucose metabolism and type 2 diabetes (T2D) than females. However, the underlying mechanisms remain to be determined. Here, we revealed that gut microbiome depletion abolished sexual dimorphism in glucose metabolism. The transfer of male donor microbiota into antibiotics-treated female mice led the recipients to be more insulin resistant. Depleting androgen via castration changed the gut microbiome of male mice to be more similar to that of females and improved glucose metabolism, while reintroducing dihydrotestosterone (DHT) reversed these alterations. More importantly, the effects of androgen on glucose metabolism were largely abolished when the gut microbiome was depleted. Next, we demonstrated that androgen modulated circulating glutamine and glutamine/glutamate (Gln/Glu) ratio partially depending on the gut microbiome, and glutamine supplementation increases insulin sensitivity in vitro. Our study identifies the effects of androgen in deteriorating glucose homeostasis partially by modulating the gut microbiome and circulating glutamine and Gln/Glu ratio, thereby contributing to the difference in glucose metabolism between the two sexes.

The adiponectin signalling pathway - A therapeutic target for the cardiac complications of type 2 diabetes?

Diabetes is associated with an increased risk of heart failure (HF). This is commonly termed diabetic cardiomyopathy and is often characterised by increased cardiac fibrosis, pathological hypertrophy, increased oxidative and endoplasmic reticulum stress as well as diastolic dysfunction. Adiponectin is a cardioprotective adipokine that is downregulated in settings of type 2 diabetes (T2D) and obesity. Furthermore, both adiponectin receptors (AdipoR1 and R2) are also downregulated in these settings which further results in impaired cardiac adiponectin signalling and reduced cardioprotection. In many cardiac pathologies, adiponectin signalling has been shown to protect against cardiac remodelling and lipotoxicity, however its cardioprotective actions in T2D-induced cardiomyopathy remain unresolved. Diabetic cardiomyopathy has historically lacked effective treatment options. In this review, we summarise the current evidence for links between the suppressed adiponectin signalling pathway and cardiac dysfunction, in diabetes. We describe adiponectin receptor-mediated signalling pathways that are normally associated with cardioprotection, as well as current and potential future therapeutic approaches that could target this pathway as possible interventions for diabetic cardiomyopathy.

Sex Differences in Nonalcoholic Fatty Liver Disease: Estrogen Influence on the Liver-Adipose Tissue Crosstalk

Significance: Nonalcoholic fatty liver disease (NAFLD) is a hepatic and systemic disorder with a complex multifactorial pathogenesis. Owing to the rising incidence of obesity and diabetes mellitus, the prevalence of NAFLD and its impact on global health care are expected to increase in the future. Differences in NAFLD exist between males and females, and among females depending on their reproductive status. Clinical and preclinical data show that females in the fertile age are more protected against NAFLD, and studies in postmenopausal women and ovariectomized animal models support a protective role for estrogens. Recent Advances: An efficient crosstalk between the liver and adipose tissue is necessary to regulate lipid and glucose metabolism, protecting the liver from steatosis and insulin resistance contributing to NALFD. New advances in the knowledge of sexual dimorphism in liver and adipose tissue are providing interesting clues about the sex differences in NAFLD pathogenesis that could inspire new therapeutic strategies. Critical Issues: Sex hormones influence key master regulators of lipid metabolism and oxidative stress in liver and adipose tissue. All these sex-biased metabolic adjustments shape the crosstalk between liver and adipose tissue, contributing to the higher protection of females to NAFLD. Future Directions: The development of novel drugs based on the protective action of estrogens, but without its feminizing or undesired side effects, might provide new therapeutic strategies for the management of NAFLD. Antioxid. Redox Signal. 35, 753-774.

Age and Sex: Impact on adipose tissue metabolism and inflammation

Age associated chronic inflammation is a major contributor to diseases with advancing age. Adipose tissue function is at the nexus of processes contributing to age-related metabolic disease and mediating longevity. Hormonal fluctuations in aging potentially regulate age-associated visceral adiposity and metabolic dysfunction. Visceral adiposity in aging is linked to aberrant adipogenesis, insulin resistance, lipotoxicity and altered adipokine secretion. Age-related inflammatory phenomena depict sex differences in macrophage polarization, changes in T and B cell numbers, and types of dendritic cells. Sex differences are also observed in adipose tissue remodeling and cellular senescence suggesting a role for sex steroid hormones in the regulation of the adipose tissue microenvironment. It is crucial to investigate sex differences in aging clinical outcomes to identify and better understand physiology in at-risk individuals. Early interventions aimed at targets involved in adipose tissue adipogenesis, remodeling and inflammation in aging could facilitate a profound impact on health span and overcome age-related functional decline.

Comparison of metabolic effects of the progestational androgens dimethandrolone undecanoate and 11β-MNTDC in healthy men

BACKGROUND

Dimethandrolone (DMA) and 11β-methyl-19-nortestosterone (11β-MNT) are two novel compounds with both androgenic and progestational activity that are under investigation as potential male hormonal contraceptives. Their metabolic effects have never been compared in men.

OBJECTIVE

Assess for changes in insulin sensitivity and adiponectin and compare the metabolic effects of these two novel androgens.

MATERIALS/METHODS

In two clinical trials of DMA undecanoate (DMAU) and 11β-MNT dodecylcarbonate (11β-MNTDC), oral prodrugs of DMA and 11β-MNT, healthy men received drug, or placebo for 28 days. Insulin and adiponectin assays were performed on stored samples. Mixed model analyses were performed to compare the effects of the two drugs. Student's t test, or the non-parametric Kruskal-Wallis test as appropriate, was used to evaluate for an effect of active drug versus placebo.

RESULTS

Class effects were seen, with decrease in HDL-C and SHBG, and increase in weight and hematocrit, with no statistically significant differences between the two compounds. No changes in fasting glucose, fasting insulin, or HOMA-IR were seen with either compound. There was a slight decrease in adiponectin with DMAU that was not seen with 11β-MNTDC. An increase in LDL-C was seen with 11β-MNTDC but not with DMAU.

DISCUSSION

There were no significant changes in insulin resistance after 28 days of oral administration of these novel androgens despite a mild increase in weight. There may be subtle differences in their metabolic impacts that should be explored in future studies.

CONCLUSION

Changes in metabolic parameters should be carefully monitored when investigating androgenic compounds.

Circulating retinol binding protein 4 levels in coronary artery disease: a systematic review and meta-analysis

BACKGROUND

Retinol binding protein 4 (RBP4) has been proposed to play a role in the pathophysiology of coronary artery disease (CAD), but previous findings on the association of RBP4 levels with CAD are inconsistent.

METHODS

A meta-analysis based on observational studies was conducted to evaluate the association between circulating RBP4 levels and CAD. Databases including PubMed, Web of Science, Embase, Google Scholar and ClinicalTrials.gov database were searched for eligible studies published up to 12 July 2021. Standard mean differences (SMDs) with 95% confidence intervals (CIs) were calculated using the inverse variance heterogeneity (IVhet) and random-effects model for data with moderate and high heterogeneity (I² > 30%) and data with low heterogeneity were analysed using a fixed-effects model (I² ≤ 30%). Moreover, a bias-adjusted quality-effects model was generated, and the prediction interval was also calculated under the random-effects model.

RESULTS

Two nested case-control studies, one cohort study and twelve case-control studies with a total of 7111 participants were included. Circulating RBP4 levels in patients with CAD were comparable to those in the controls under the IVhet model (SMD: 0.25, 95% CI: - 0.29-0.79, I²: 96.00%). The quality-effects model produced consistent results. However, the association turned to be significant under the random-effect model (SMD: 0.46, 95% CI: 0.17-0.75, I²: 96.00%), whereas the 95% predictive interval (PI) included null values (95% PI: - 0.82-1.74). Subgroup analyses illustrated a positive relationship between CAD and RBP4 levels in patients with complications (SMD: 1.34, 95% CI: 0.38-2.29, I²: 96.00%). The meta-regression analysis revealed that the mean BMI of patients (P = 0.03) and complication status (P = 0.01) influenced the variation in SMD.

CONCLUSIONS

There was low-quality evidence that patients with CAD exhibited similar circulating RBP4 levels compared with controls, and high inter-study heterogeneity was also observed. Thus, RBP4 might not be a potential risk factor for CAD. Comparisons among different subtypes of RBP4 with larger sample size are needed in the future.

Effects of Synbiotic Supplementation and Lifestyle Modifications on Women With Polycystic Ovary Syndrome

CONTEXT

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy affecting women of reproductive age.

OBJECTIVE

This study was designed to evaluate effects of lifestyle modifications and synbiotic supplementation on PCOS.

DESIGN

A randomized (1:1) double-blind, placebo-controlled trial.

SETTING

Academic hospital.

PATIENTS OR OTHER PARTICIPANTS

Overweight and obese women with PCOS were identified according to the Rotterdam criteria. Evaluations were performed at baseline and repeated after 3 months of treatment.

INTERVENTION

Lifestyle modifications in combination with synbiotic supplementation or placebo.

MAIN OUTCOME MEASURES

Change in body mass index (BMI) and testosterone level.

RESULTS

In the placebo group, a 5% decrease in BMI was accompanied by significant decreases of the waist, hip, and thigh circumferences. The synbiotic group experienced an 8% decrease in BMI, which was significantly greater than that in the control group (P = 0.03) and was accompanied by decreases in the waist, hip, and thigh circumferences. Testosterone did not decrease significantly in the placebo group (decrease of 6%), whereas in the synbiotic group it decreased by 32% (P < 0.0001). The decrease of testosterone was significantly greater in the synbiotic group than in the placebo group (P = 0.016).

CONCLUSIONS

Synbiotic supplementation potentiated effects of lifestyle modifications on weight loss and led to significant reduction of serum testosterone.

Fat biology and metabolic balance: On the significance of sex

Obesity and its related metabolic disorders have become prevalent and fatal, which are faced by the entire human beings since decades. An energy equilibrium is urgently important for human metabolic health, which requires the participation of multiple organs, such as adipose tissues, liver and skeletal muscles. It seems that both sex and age play a role in the above processes. In this review, we focus on the sexual dimorphism in energy metabolism mediated by adipose tissues, including white and thermogenic (brown/beige) adipose tissues. Remarkably, past investigations have focused on targeting brown/beige adipose tissues to combat obesity because of their contributions to non-shivering thermogenesis. However, sex differences in the regulation of adipose tissue metabolism are likely overlooked. Particularly, increasing data show that males display more visceral fat than females, and females show increased visceral fat after menopause. Visceral adiposity is more deleterious and closely related to metabolic disorders, such as cardiovascular diseases. In this review, we discuss current findings on sexual dimorphism in WAT and BAT biology for a better metabolic balance in humans.

Changes in abdominal subcutaneous adipose tissue phenotype following menopause is associated with increased visceral fat mass

Menopause is associated with a redistribution of adipose tissue towards central adiposity, known to cause insulin resistance. In this cross-sectional study of 33 women between 45 and 60 years, we assessed adipose tissue inflammation and morphology in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) across menopause and related this to menopausal differences in adipose tissue distribution and insulin resistance. We collected paired SAT and VAT biopsies from all women and combined this with anthropometric measurements and estimated whole-body insulin sensitivity. We found that menopause was associated with changes in adipose tissue phenotype related to metabolic dysfunction. In SAT, postmenopausal women showed adipocyte hypertrophy, increased inflammation, hypoxia and fibrosis. The postmenopausal changes in SAT was associated with increased visceral fat accumulation. In VAT, menopause was associated with adipocyte hypertrophy, immune cell infiltration and fibrosis. The postmenopausal changes in VAT phenotype was associated with decreased insulin sensitivity. Based on these findings we suggest, that menopause is associated with changes in adipose tissue phenotype related to metabolic dysfunction in both SAT and VAT. Whereas increased SAT inflammation in the context of menopause is associated with VAT accumulation, VAT morphology is related to insulin resistance.