Classic and Novel Sex Hormone Binding Globulin Effects on the Cardiovascular System in Men

Sex hormone-binding globulin and its critical role in prostate cancer: A comprehensive review

Prostate cancer (PC) is a common and widespread cancer that affects men globally. A complicated interaction of hormonal variables influences its development. Sex hormone-binding globulin (SHBG) is a crucial element in controlling the availability of sex hormones, especially androgens, which have a notable impact on the development and progression of PC. SHBG controls the levels of free, active androgens in the body, which helps regulate androgen-dependent processes associated with PC. The equilibrium between SHBG and androgens plays a critical role in maintaining the stability of the prostate. When this balance is disrupted, it is associated with the development and advancement of PC. The processes responsible for SHBG's role in PC are complex and have multiple aspects. SHBG primarily binds to androgens, preventing them from interacting with androgen receptors (ARs) in prostate cells. It reduces the activation of androgen signaling pathways essential for tumor development and survival. In addition, SHBG can directly affect prostate cells by interacting with specific receptors on the cell surface. This review thoroughly examines the role of SHBG in PC, including its physiological activities, methods of action, and clinical consequences.

Metabolic dysfunction-associated steatotic liver disease-associated fibrosis and cardiac dysfunction in patients with type 2 diabetes

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD), particularly in the presence of liver fibrosis, increases the risk of cardiovascular morbidity and mortality, but the nature of the cardio-hepatic interaction in the context type 2 diabetes mellitus (T2DM) is not fully understood.

AIM

To evaluate the changes in cardiac morphology and function in patients with T2DM and MASLD-associated liver fibrosis.

METHODS

T2DM patients with MASLD underwent a medical evaluation that included an assessment of lifestyle, anthropometric measurements, vital signs, an extensive laboratory panel, and a standard echocardiography. Liver fibrosis was evaluated using two scores [Fibrosis-4 (FIB4) and Non-alcoholic fatty liver disease-Fibrosis Score (NFS)], and subjects were classified as having advanced fibrosis, no fibrosis, or an indeterminate risk. The correlations between structural and functional cardiac parameters and markers of liver fibrosis were evaluated through bivariate and multiple regression analyses. Statistical significance was set at P < 0.05.

RESULTS

Data from 267 T2DM-MASLD subjects with complete assessment was analyzed. Patients with scores indicating advanced fibrosis exhibited higher interventricular septum and left ventricular (LV) posterior wall thickness, atrial diameters, LV end-systolic volume, LV mass index (LVMi), and epicardial adipose tissue thickness (EATT). Their mean ejection fraction (EF) was significantly lower (49.19% ± 5.62% vs 50.87% ± 5.14% vs 52.00% ± 3.25%; P = 0.003), and a smaller proportion had an EF ≥ 50% (49.40% vs 68.90% vs 84.21%; P = 0.0017). Their total and mid LV wall motion score indexes were higher (P < 0.05). Additionally, they had markers of diastolic dysfunction, with a higher E/e' ratio [9.64 ± 4.10 vs 8.44 (2.43-26.33) vs 7.35 ± 2.62; P = 0.026], and over 70% had lateral e' values < 10 cm/second, though without significant differences between groups. In multiple regression analyses, FIB4 correlated with left atrium diameter (LAD; β = 0.044; P < 0.05), and NFS with both LAD (β = 0.039; P < 0.05) and right atrium diameter (β = 0.041; P < 0.01), Moreover, LVMi correlated positively with age and EATT (β = 1.997; P = 0.0008), and negatively with serum sex-hormone binding protein (SHBP) concentrations (β = -0.280; P = 0.004). SHBP also correlated negatively with LAD (β = -0.036; P < 0.05).

CONCLUSION

T2DM patients with markers of MASLD-related liver fibrosis exhibit lower EF and present indicators of diastolic dysfunction and cardiac hypertrophy. Additionally, LVMi and LAD correlated negatively with serum SHBP concentrations.

Sex hormone binding globulin (SHBG) modulates mitochondrial dynamics in PPARγ-depleted equine adipose derived stromal cells

Peroxisome proliferator-activated receptor gamma (PPARγ) is a transcription factor that promotes adipogenesis, lipid uptake and storage, insulin sensitivity, and glucose metabolism. Hence, defects in PPARγ have been associated to the development of metabolic disorders. Sex hormone-binding globulin (SHBG) is a glycoprotein primarily produced in the liver that regulates the bioavailability of sex hormones. Alike PPARγ, low SHBG levels have been correlated with insulin resistance and associated endocrine abnormalities. Therefore, this study aimed to verify whether SHBG may restore depleted PPARγ functions and thus serve as a new candidate for the management of metabolic conditions. A model of equine adipose-derived stromal cells (EqASCs) has been used, in which a PPARγ silencing and SHBG treatment have been achieved to determine the changes in cell viability, premature senescence, oxidative stress, and mitochondrial functions. Obtained data demonstrated that loss in PPARγ triggers cell apoptosis which is not reversed by SHBG application. Moreover, PPARγ knockdown cells exhibited premature senescence, which has been substantially alleviated by SHBG concomitantly to increased BAX/BCL2 ratio, suggesting a possible effect on senescence-induced apoptosis resistance. Interestingly, PPARγ silencing induced a significant alteration in mitochondrial membrane potential as well as the expression of dynamics and metabolism-related markers. SHBG treatment enabled to ameliorate the transmembrane potential, to normalize the expression levels of key dynamics and metabolism mediators, and to restore the protein levels of PINK, which is critically involved in mitochondria recycling machinery. Presented data suggest that SHBG may provide new mechanistic insights into the regulation of PPARγ functions, and thus offers a preliminary picture on a possible SHBG-PPARγ metabolic crosstalk. KEY MESSAGES : PPARγ is a transcription factor that tightly regulates cell metabolism. Low SHBG levels correlate with insulin resistance and associated endocrine abnormalities. PPARγ silencing reduces cell viability, triggers premature senescence and profound mitochondrial failure in equine ASCs. SHBG protein reverses senescent phenotype and apoptosis resistance of PPARγ- ASCs. SHBG improves mitochondrial dynamics and metabolism following PPARγ knockdown. SHBG might serve as a PPARγ potential mimicking agent for the modulation of ASCs metabolic processes.

Sex hormone binding globulin (SHBG) serum levels and insulin resistance in men on chronic hemodialysis

BACKGROUND

In males with end stage renal disease biochemical hypogonadism is a frequent finding. Testosterone and sex hormone binding globulin (SHBG) have been associated with insulin resistance, a well-known condition in uremia. The aim of the present study was to investigate in males on chronic hemodialysis the relationship of testosterone and SHBG serum levels with insulin resistance.

METHODS

In a cross-sectional study we enrolled men treated with chronic hemodialysis who did not suffer from an acute illness or other endocrinopathy, as well as primary hypogonadism, and were not hospitalised. Diabetes mellitus, diabetic nephropathy or previous transplantation were not exclusion criteria. As controls we used a community-based group of healthy males matched for age and Body Mass Index (BMI). We assessed the BMI (kg/m2) from body weight and height, the body fat content (%) by bioelectrical impedance and serum testosterone (ng/ml), SHBG (nmol/L) and estradiol (pg/ml) by standard methods. Testosterone < 3.25 ng/ml defined biochemical hypogonadism. In non-diabetic males, we calculated the homeostasis model assessment index (HOMA-R), an estimate of insulin resistance, from serum fasting insulin and glucose.

RESULTS

27 men (age 54.4 ± 19 years) on chronic hemodialysis (treatment duration 29.1 ± 14.4 months) and 51 healthy men (age 47.1 ± 9.6 years) were included. In men on hemodialysis vs. healthy men there were increased serum levels of SHBG (40.9 ± 26.9 vs. 27.6 ± 11.9 nmol/L; p = 0.031) and a significantly enhanced frequency of biochemical hypogonadism (22.2 vs. 3.9%; p = 0.011). In cases without diabetes (n = 22) a significant correlation was observed between the HOMA-R (r = -0.586, p = 0.004) and the fasting insulin levels (r = -0.650, p = 0.001) on the one hand and the serum SHBG levels on the other.

CONCLUSIONS

Our findings confirm enhanced prevalence of biochemical hypogonadism in males on chronic hemodialysis. In non-diabetic cases the serum levels of SHBG correlated with serum insulin and insulin resistance.

Blood lipid levels mediating the effects of sex hormone-binding globulin on coronary heart disease: Mendelian randomization and mediation analysis

Observational studies indicate that serum sex hormone-binding globulin (SHBG) levels are inversely correlated with blood lipid levels and coronary heart disease (CHD) risk. Given that dyslipidemia is an established risk factor for CHD, we aim to employ Mendelian randomization (MR) in conjunction with mediation analysis to confirm the mediating role of blood lipid levels in the association between SHBG and CHD. First, we assessed the causality between serum SHBG levels and five cardiovascular diseases using univariable MR. The results revealed causality between SHBG levels and reduced risk of CHD, myocardial infarction, as well as hypertension. Specifically, the most significant reduction was observed in CHD risk, with an odds ratio of 0.73 (95% CI 0.63-0.86) for each one-standard-deviation increase in SHBG. The summary-level data of serum SHBG levels and CHD are derived from a sex-specific genome-wide association study (GWAS) conducted by UK Biobank (sample size = 368,929) and a large-scale GWAS meta-analysis (60,801 cases and 123,504 controls), respectively. Subsequently, we further investigated the mediating role of blood lipid level in the association between SHBG and CHD. Mediation analysis clarified the mediation proportions for four mediators: high cholesterol (48%), very low-density lipoprotein cholesterol (25.1%), low-density lipoprotein cholesterol (18.5%), and triglycerides (44.3%). Summary-level data for each mediator were sourced from the UK Biobank and publicly available GWAS. The above results confirm negative causality between serum SHBG levels and the risk of CHD, myocardial infarction, and hypertension, with the causal effect on reducing CHD risk largely mediated by the improvement of blood lipid profiles.

Considering hormones as sex- and gender-related factors in biomedical research: Challenging false dichotomies and embracing complexity

The inclusion of sex and gender considerations in biomedicine has been increasing in light of calls from research and funding agencies, governmental bodies, and advocacy groups to direct research attention to these issues. Although the inclusion of both female and male participants is often an important element, overreliance on a female-male binary tends to oversimplify the interactions between sex- and gender-related factors and health, and runs a risk of being influenced by cultural stereotypes about sex and gender. When biomedical researchers are examining how hormones associated with gender and sex may influence pathways of interest, it is of crucial importance to approach this work with a critical lens on the rhetoric used, and in ways that acknowledge the complexity of hormone physiology. Here, we document the ways in which discourses around sex, gender and hormones shape our scientific thinking and practice in biomedical research, and review how the existing scientific knowledge about hormones reflects a complex and dynamic reality that is often not reflected outside of specialist niches of hormone biology. Where biomedical scientists take up sex- and gender-associated hormones as a way of addressing sex and gender considerations, it is valuable for us to bring a critical lens to the rhetoric and discourses used, to employ a sex contextualist approach in designing experimentation, and be rigorous and reflexive about the approaches used in analysis and interpretation of data. These strategies will allow us to design experimentation that goes beyond binaries, and grapples more directly with the material intricacies of sex, gender, and hormones.

Sex Hormone-Binding Globulin (SHBG) Maintains Proper Equine Adipose-Derived Stromal Cells (ASCs)' Metabolic Functions and Negatively Regulates their Basal Adipogenic Potential

BACKGROUND

Sex hormone binding globulin (SHBG) deteriorated expression has been recently strongly correlated to increased level of circulating pro-inflammatory cytokines and insulin resistance, which are typical manifestations of equine metabolic syndrome (EMS). Despite previous reports demonstrated the potential therapeutic application of SHBG for liver-related dysfunctions, whether SHBG might modulate equine adipose-derived stem/stromal cells (EqASCs) metabolic machinery remains unknown. Therefore, we evaluated for the first time the impact of SHBG protein on metabolic changes in ASCs isolated from healthy horses.

METHODS

Beforehand, SHBG protein expression has been experimentally lowered using a predesigned siRNA in EqASCs to verify its metabolic implications and potential therapeutic value. Then, apoptosis profile, oxidative stress, mitochondrial network dynamics and basal adipogenic potential have been evaluated using various molecular and analytical techniques.

RESULTS

The SHBG knockdown altered the proliferative and metabolic activity of EqASCs, while dampening basal apoptosis via Bax transcript suppression. Furthermore, the cells treated with siRNA were characterized by senescent phenotype, accumulation of reactive oxygen species (ROS), nitric oxide, as well as decreased mitochondrial potential that was shown by mitochondrial membrane depolarization and lower expression of key mitophagy factors: PINK, PARKIN and MFN. The addition of SHBG protein reversed the impaired and senescent phenotype of EMS-like cells that was proven by enhanced proliferative activity, reduced apoptosis resistance, lower ROS accumulation and greater mitochondrial dynamics, which is proposed to be related to a normalization of Bax expression. Crucially, SHBG silencing enhanced the expression of key pro-adipogenic effectors, while decreased the abundance of anti-adipogenic factors namely HIF1-α and FABP4. The addition of exogenous SHBG further depleted the expression of PPARγ and C/EBPα and restored the levels of FABP4 and HIF1-α evoking a strong inhibitory potential toward ASCs adipogenesis.

CONCLUSION

Herein, we provide for the first time the evidence that SHBG protein in importantly involved in various key metabolic pathways governing EqASCs functions, and more importantly we showed that SHBG negatively affect the basal adipogenic potential of tested ASCs through a FABP4-dependant pathway, and provide thus new insights for the development of potential anti-obesity therapeutic approach in both animals and humans.

Genetic regulation of testosterone level in overweight males from the Kazakh population and its association with hypogonadism

Male hypogonadism and erectile dysfunction in different populations are associated with excess body weight. A key aspect in most studies is the metabolism of sexual hormones, primarily testosterone. At the same time, the binding protein sex hormone binding globulin (SHBG) can play a large role, as it determines the ratio of total and bioavailable testosterone in blood, i.e. both the hormone content and level of its production. Recent research has identified common mutations that affect SHBG levels, such as the rs727428 polymorphic locus, which is associated with alterations in histone protein function, affecting the regulation of ribonucleic acid (RNA) protein SHBG synthesis. Similar relationships have been observed for prevalent mutations, including rs5934505 and rs10822184, in diverse populations. This study involved 300 individuals of Kazakh nationality from the Eastern Kazakhstan region, examining three polymorphic variants of the SHBG gene (rs727428, rs5934505, and rs10822184). The participants were categorized into three groups: individuals with hypogonadism and obesity (group 1, n=85), those with excess body weight but no hypogonadism (group 2, n=70), and individuals with neither excess body weight nor hypogonadism (group 3, n=145). The frequency of mutant gene alleles impacting GPS (SHBG) synthesis in the Kazakh population was notably high, comparable to European and South-East Asian populations. However, the association between excess body weight and these mutations exhibited varying patterns. Hypogonadism was linked to decreased GPS levels, strongly correlating with total testosterone but not bioavailable testosterone. The retention of sexual functions in overweight men was not always directly related to BMI levels and GPS concentrations.

Association Between Sex Hormone-Binding Globulin, Atherogenic Indices of Plasma Among Young Sedentary Males

Background

Males are more likely than females to suffer from cardiovascular disease (CVD). So, sex hormones may modify these variations and affect the lipid profile. We examined the relationship between sex hormone-binding globulin (SHBG) and CVD risk factors among young males in this study.

Methods

Using a cross-sectional design, we measured total testosterone, SHBG, lipids, glucose, insulin, antioxidant parameters, and anthropometric factors in 48 young males in the age range of 18 to 40 years. Atherogenic indices of plasma were calculated. In this study, a partial correlation analysis was carried out to assess the relationship between SHBG and other variables after adjustment for confounders.

Results

According to the results of multivariable analyses adjusted for age and energy, SHBG had a negative correlation with total cholesterol (r = -.454, P =.010), low-density lipoprotein cholesterol (r = -.496, P =.005), quantitative insulin-sensitivity check index, and positive correlation with high-density lipoprotein cholesterol (r = .463, P =.009). No significant correlation was observed between SHBG and triglycerides (P >.05). Several atherogenic indices of plasma have a negative correlation with SHBG levels. These include Atherogenic Index of Plasma (r = -.474, P = .006), Castelli Risk Index (CRI)1 (r = -.581, P < .001), CRI2 (r = -.564, P = .001), and Atherogenic Coefficient (r = -.581, P < .001).

Conclusion

Among young men, high plasma SHBG was associated with reduced CVD risk factors, modified lipid profile and atherogenic ratios, and better glycemic markers. Therefore, reduced SHBG concentrations could be a prognostic marker of CVD among young sedentary males.

Regulatory network and interplay of hepatokines, stellakines, myokines and adipokines in nonalcoholic fatty liver diseases and nonalcoholic steatohepatitis

Fatty liver disease is a spectrum of liver pathologies ranging from simple hepatic steatosis to non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and culminating with the development of cirrhosis or hepatocellular carcinoma (HCC). The pathogenesis of NAFLD is complex and diverse, and there is a lack of effective treatment measures. In this review, we address hepatokines identified in the pathogenesis of NAFLD and NASH, including the signaling of FXR/RXR, PPARα/RXRα, adipogenesis, hepatic stellate cell activation/liver fibrosis, AMPK/NF-κB, and type 2 diabetes. We also highlight the interaction between hepatokines, and cytokines or peptides secreted from muscle (myokines), adipose tissue (adipokines), and hepatic stellate cells (stellakines) in response to certain nutritional and physical activity. Cytokines exert autocrine, paracrine, or endocrine effects on the pathogenesis of NAFLD and NASH. Characterizing signaling pathways and crosstalk amongst muscle, adipose tissue, hepatic stellate cells and other liver cells will enhance our understanding of interorgan communication and potentially serve to accelerate the development of treatments for NAFLD and NASH.

Androgens, brain and androgen deprivation therapy in paraphilic disorders: A narrative review

Sexual delinquency is a global problem where those with paraphilic disorders, such as paedophiles, are more likely to commit and reoffend. Androgen deprivation therapy (ADT) has been suggested as a solution. The objective of this narrative review is to present current information on its risks, benefits and limitations as a treatment for paraphilias. The importance of testosterone in sexual function, the effect of its deficiency by age or by pharmacological treatment (anti-androgens, GnRH agonists and GnRH antagonists) and the effect of testosterone replacement therapy will be reviewed. The relationship between androgens, brain, sexual behaviour and pathophysiology of paraphilic disorders will also be explored. ADT reduces sexual urges, but has adverse effects and, because its reversible nature, it does not ensure less recidivism. Likewise, the research quality of ADT drugs is limited and not enough to support their use. Child sex offenders, and not paraphilic subjects who have not committed assaults, show signs of elevated prenatal exposure to androgens and a higher methylation state of the androgen receptor gene. Sexual behaviour is regulated by subcortical (hypothalamus, brainstem and spinal cord) and cortical structures of the brain, in addition to brain circuits (dopaminergic, serotonergic). Those with paraphilic disorders show abnormalities at these levels that could relate to the risk of sexual offences. In conclusion, androgens represent a significant part of the pathophysiology of paraphilias and therefore, ADT seems promising. Nonetheless, more studies are needed to make definite conclusions about the efficacy of long-term ADT in paraphilic patients.

Low testosterone predicts hypoxemic respiratory insufficiency and mortality in patients with COVID-19 disease: another piece in the COVID puzzle

PURPOSE

Hypogonadism was described in high number of male subjects with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In this study, we investigated whether low testosterone (T) values may influence the clinical presentation and outcome of SARS-CoV-2-related pneumonia in a large population of adult males with coronavirus disease 19 (COVID-19).

METHODS

Two hundred twenty one adult males hospitalized for COVID-19 at the IRCCS Humanitas Research Hospital, Rozzano-Milan (Italy) were consecutively evaluated for arterial partial pressure oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) ratio, serum T and inflammatory parameters at study entry, need of ventilation during hospital stay and in-hospital mortality.

RESULTS

Subjects low T values (< 8 nmol/L; 176 cases) were significantly older (P = 0.001) and had higher serum interleukin-6 (P = 0.001), C-reactive protein (P < 0.001), lactate dehydrogenase (P < 0.001), ferritin (P = 0.012), lower P/F ratio (P = 0.001), increased prevalence of low T3 syndrome (P = 0.041), acute respiratory insufficiency (P < 0.001), more frequently need of ventilation (P < 0.001) and higher mortality rate (P = 0.009) compared to subjects with higher T values. In the multivariable regression analyses, T values maintained significant associations with acute respiratory insufficiency (odds ratio [OR] 0.85, 95% confidence interval [CI] 0.79-0.94; P < 0.001 and in-hospital mortality (OR 0.80, 95% CI 0.69-0.95; P = 0.009), independently of age, comorbidities, thyroid function and inflammation.

CONCLUSION

Low T levels values are associated with unfavorable outcome of COVID-19. Prospective studies are needed to evaluate the long-term outcomes of hypogonadism related to COVID-19 and the clinical impact of T replacement during and after acute illness.

Sex Hormone-Binding Globulin and Its Association to Cardiovascular Risk Factors in an Italian Adult Population Cohort

Abnormal sex hormone-binding globulin (SHBG) and sex hormone concentrations are the cause or the consequence of cardiometabolic diseases, however, the clinical correlates of SHBG is clearly less understood. In our study we investigate sex- and age-specific serum SHBG levels and their association with cardiovascular risk (CVR) factors and high-risk conditions in an adult cohort of Italian population. Data from 1176 men and 2236 women, aged 20–81 were analyzed and serum SHBG determined in stored samples using an immunoassay. SHBG concentrations, higher in women than in men in the younger age groups, exhibited a curvilinear increase with age in men and a U-shaped curve across the lifespan in women, with a decrease from the 2nd to the 6th decade of age and an increase after the 6th decade when SHBG concentrations were similar in both sexes. Low SHBG serum levels correlated with the traditional CVR factors diabetes, obesity, and hypertension, whereas high level of SHBG correlated with cholesterol HDL. These associations were more numerous in women than in men, in whom decreased with age. The sex- and age specific differences observed in our population-based cohort should be considered in establishing reference ranges and clinical cut-off points to improve CVR score charts and therapeutic approaches.