Hypogonadism and male obesity: Focus on unresolved questions

The influence of body composition on the response to dynamic stimulation of the endocrine pituitary-testis axis

BACKGROUND

Testosterone treatment is generally not recommended in men with obesity induced low serum testosterone. However, distinguishing this condition from overt testosterone deficiency in men with obesity where treatment should be initiated is a diagnostic challenge and tools to differentiate these conditions are scarce but could be of important clinical relevance.

OBJECTIVES

To investigate the association between body composition and dynamic responses of the pituitary-testis axis in men.

METHODS

Single-center cross-sectional study including 112 healthy men. Participants went through a full biochemical assessment of the pituitary-testis axis, and dynamic stimulatory tests of luteinizing hormone (LH) secretion (gonadotropin-releasing hormone (GnRH)-test) and testosterone secretion (choriogonadotropin (hCG)-test). A subset (N = 78) further had a DXA-scan performed.

RESULTS

A higher body mass index (BMI) was associated with lower basal serum LH (BU = -0.44, 95% CI: -0.88--0.01, p = 0.04). The GnRH-stimulated LH increase was not significantly associated with BMI (BU = -0.10, 95% CI: -0.72-0.51, p = 0.74). Furthermore, a high BMI was associated with low basal testosterone (BU -0.02, 95% CI: -0.03--0.02, p < 0.001), and free testosterone (BU -15.0, 95% CI: -19.9--10.0, p < 0.001) and men with overweight and obesity had significantly lower testosterone (9%, p = 0.003 and 24%, p < 0.001) and free testosterone (25%, p = 0.006 and 50%, p < 0.001) concentrations compared to men with normal weight. The HCG-stimulated testosterone increase was significantly less dependent on BMI compared to the influence of BMI on basal testosterone concentrations (p = 0.04 for the interaction).

CONCLUSIONS

Dynamic sex hormone responses following pituitary-testis axis stimulation were less dependent on BMI, compared to the influence of BMI on basal hormone concentrations and could potentially assist clinical decision making in patients with obesity suspected of testosterone deficiency.

Male hypogonadism: pathogenesis, diagnosis, and management

Organic male hypogonadism due to irreversible hypothalamic-pituitary-testicular (HPT) pathology is easily diagnosed and treated with testosterone-replacement therapy. However, controversy surrounds the global practice of prescribing testosterone to symptomatic men with low testosterone and non-gonadal factors reducing health status, such as obesity, type 2 diabetes, and ageing (ie, functional hypogonadism), but without identifiable HPT axis pathology. Health optimisation remains the gold-standard management strategy. Nevertheless, in the last decade large clinical trials and an individual patient data meta-analysis of smaller clinical trials confirmed that testosterone therapy induces modest, yet statistically significant, improvements in sexual function without increasing short-term to medium-term cardiovascular or prostate cancer risks in men with functional hypogonadism. Although testosterone improves bone mineral density and insulin sensitivity in these men, trials from the last decade suggest insufficient evidence to determine the safety and effectiveness of use of this hormone for the prevention of fractures or type 2 diabetes. This Review discusses the pathogenesis and diagnosis of male hypogonadism and appraises the evidence underpinning the management of this condition.

Association between metabolic obesity phenotypes and the risk of developing prostate cancer: a propensity score matching study based on Xinjiang

Background

Obesity-induced metabolic dysfunction increases the risk of developing tumors, however, the relationship between metabolic obesity phenotypes and prostate cancer (PCa) remains unclear.

Methods

The term metabolic obesity phenotypes was introduced based on metabolic status and BMI categories. Participants were categorized into four groups: metabolically healthy nonobesity (MHNO), metabolically healthy obesity (MHO), metabolically unhealthy nonobesity (MUNO), and metabolically unhealthy obesity (MUO). Propensity score matching was conducted based on age, ethnicity, marriage, etc. Univariate and multivariate conditional logistic regression analyses were used to assess the relationship between metabolic obesity phenotypes, metabolic risk factors, and PCa. Sensitivity analysis was performed to verify the robustness of the results.

Results

After propensity score matching among 564 PCa patients and 1418 healthy individuals, 209 were selected for each of the case and control groups. There were no statistically significant differences in the basic characteristics between the two groups. Univariate and multivariate conditional logistic regression suggested that the risk of developing PCa in both MHO and MUO individuals was higher than in MHNO individuals. Specifically, the risk of developing PCa in MHO individuals was 2.166 times higher than in MHNO individuals (OR=2.166, 95%CI: 1.133-4.139), and the risk in MUO individuals was is 2.398 times higher than in MHNO individuals(OR=2.398, 95%CI:1.271-4.523). Individuals with hyperglycemia and elevated triglycerides also had a higher risk of developing PCa (hyperglycemia:OR=1.488, 95%CI: 1.001-2.210; elevated triglycerides: OR=2.292, 95%CI: 1.419-3.702). Those with more than or equal to three metabolic risk factors had an increased risk of PCa (OR=1.990, 95%CI: 1.166-3.396). Sensitivity analysis indicated an increased risk of PCa in MUO individuals compared to MHNO individuals.

Conclusion

In this retrospective study, individuals with MHO and MUO had a higher risk of developing PCa.

The evolutionary conserved miR-137/325 tandem mediates obesity-induced hypogonadism and metabolic comorbidities by repressing hypothalamic kisspeptin

BACKGROUND

Obesity-induced hypogonadism (OIH) is a prevalent, but often neglected condition in men, which aggravates the metabolic complications of overweight. While hypothalamic suppression of Kiss1-encoded kisspeptin has been suggested to contribute to OIH, the molecular mechanisms for such repression in obesity, and the therapeutic implications thereof, remain unknown.

METHODS

A combination of bioinformatic, expression and functional analyses was implemented, assessing the role of the evolutionary-conserved miRNAs, miR-137 and miR-325, in mediating obesity-induced suppression of hypothalamic kisspeptin, as putative mechanism of central hypogonadism and metabolic comorbidities. The implications of such miR-137/325-kisspeptin interplay for therapeutic intervention in obesity were also explored using preclinical OIH models.

RESULTS

MiR-137/325 repressed human KISS1 3'-UTR in-vitro and inhibited hypothalamic kisspeptin content in male rats, while miR-137/325 expression was up-regulated, and Kiss1/kisspeptin decreased, in the medio-basal hypothalamus of obese rats. Selective over-expression of miR-137 in Kiss1 neurons reduced Kiss1/ kisspeptin and partially replicated reproductive and metabolic alterations of OIH in lean mice. Conversely, interference of the repressive actions of miR-137/325 selectively on Kiss1 3'-UTR in vivo, using target-site blockers (TSB), enhanced kisspeptin content and reversed central hypogonadism in obese rats, together with improvement of glucose intolerance, insulin resistance and cardiovascular and inflammatory markers, despite persistent exposure to obesogenic diet. Reversal of OIH by TSB miR-137/325 was more effective than chronic kisspeptin or testosterone treatments in obese rats.

CONCLUSIONS

Our data disclose that the miR-137/325-Kisspeptin repressive interaction is a major player in the pathogenesis of obesity-induced hypogonadism and a putative druggable target for improved management of this condition and its metabolic comorbidities in men suffering obesity.

SIGNIFICANCE STATEMENT

Up to half of the men suffering obesity display also central hypogonadism, an often neglected complication of overweight that can aggravate the clinical course of obesity and its complications. The mechanisms for such obesity-induced hypogonadism remain poorly defined. We show here that the evolutionary conserved miR137/miR325 tandem centrally mediates obesity-induced hypogonadism via repression of the reproductive-stimulatory signal, kisspeptin; this may represent an amenable druggable target for improved management of hypogonadism and other metabolic complications of obesity.

Testosterone in prevention and treatment of type 2 diabetes in men: Focus on recent randomized controlled trials

In epidemiological studies, lowered serum testosterone concentrations are common in men with obesity, prediabetes, and established type 2 diabetes (T2D). In men with prediabetes, lowered serum testosterone also predicts a future risk of T2D in men. Administration of testosterone consistently reduces fat mass and increases skeletal muscle mass-body compositional changes expected to be metabolically favorable. In men with established T2D, the effects of testosterone treatment on glycemic measures are inconsistent. Irrespective of baseline serum testosterone concentration in men with prediabetes or newly diagnosed early-onset T2D, testosterone treatment prescribed in conjunction with a lifestyle program has been reported to reduce the risk of T2D by 40% after 2 years, suggesting that either a lifestyle program is required to facilitate the glycemic benefit of testosterone treatment and/or that testosterone treatment has more favorable effects on glycemia in men early in the evolution or onset of the disease. The durability of the benefit and longer-term safety of testosterone treatment have not been established. Therefore, more studies are required before testosterone treatment can be recommended for the prevention and/or treatment of men with or at elevated risk of T2D who do not have hypogonadism due to an established disease of the hypothalamic-pituitary-testicular axis.

Association between weight-adjusted waist index and testosterone deficiency in adult American men: findings from the national health and nutrition examination survey 2013-2016

BACKGROUND

Testosterone deficiency (TD) and obesity are globally recognized health concerns, with a bidirectional causal relationship between them. And a newly discovered obesity indicator, the Weight-Adjusted-Waist Index (WWI), has been proposed, demonstrating superior adiposity identification capability compared to traditional body mass index (BMI) and waist circumference (WC) indicators. Therefore, we present the inaugural investigation into the associations of WWI with total testosterone levels and the risk of TD.

METHODS

Data restricted to the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2016 were analyzed. Only males aged > 20 years who completed body measures and underwent serum sex hormone testing were potentially eligible for analysis. Weighted multivariable linear regression and logistic regression analyses were employed to investigate the relationships between WWI and total testosterone levels, and the risk of TD, respectively. Smooth curve fittings and weighted generalized additive model (GAM) regression were conducted to examine the linear relationship among them. Additionally, subgroup analyses with interaction tests were performed to assess the stability of the results.

RESULTS

Finally, a total of 4099 participants with complete data on testosterone and WWI were included in the formal analysis. The mean age of study participants was 46.74 ± 0.35 years with a TD prevalence of 25.54%. After adjusting all potential confounders, the continuous WWI displayed a negative linear relationship with total testosterone levels (β=-61.41, 95%CI: -72.53, -50.29, P < 0.0001) and a positive linear relationship with risk of TD (OR = 1.88, 95%CI: 1.47, 2.39, P < 0.0001). When WWI was transformed into quartiles as a categorical variable, participants in Q4 exhibited lower total testosterone levels (β=-115.4, 95%CI: -142.34, -88.45, P < 0.0001) and a higher risk of TD (OR = 3.38, 95% CI: 2.10, 5.44, P < 0.001). These associations remained stable in subgroup analyses without significant interaction (all P for interaction > 0.05).

CONCLUSIONS

This investigation firstly unveiled a negative linear association between WWI and total testosterone levels, coupled with a positive linear relationship with the prevalence of TD in U.S. male adults aged 20 years and older. Further studies are needed to validate the potential utility of WWI for the early identification and timely intervention of TD.

Hypogonadism and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), recently proposed to be renamed to metabolic dysfunction-associated steatotic liver disease (MASLD), is a major global public health concern, affecting approximately 25-30% of the adult population and possibly leading to cirrhosis, hepatocellular carcinoma, and liver transplantation. The liver is involved in the actions of sex steroids via their hepatic metabolism and production of the sex hormone-binding globulin (SHBG). Liver disease, including NAFLD, is associated with reproductive dysfunction in men and women, and the prevalence of NAFLD in patients with hypogonadism is considerable. A wide spectrum of possible pathophysiological mechanisms linking NAFLD and male/female hypogonadism has been investigated. As therapies targeting NAFLD may impact hypogonadism in men and women, and vice versa, treatments of the latter may affect NAFLD, and an insight into their pathophysiological pathways is imperative. This paper aims to elucidate the complex association between NAFLD and hypogonadism in men and women and discuss the therapeutic options and their impact on both conditions.

Advances in the treatment of functional male hypogonadism

INTRODUCTION

Functional hypogonadism is frequently found in obese men, particularly those with metabolic complications. Several possible therapeutic approaches could be considered.

AREAS COVERED

An extensive search on Medline, Embase, and Cochrane databases was performed to retrieve the available studies assessing the change of testosterone (T) and sexual function upon dieting or physical activity programs, as well as glucagon-like peptide 1 analogues. The role of lifestyle interventions associated with T replacement therapy (TRT) was also evaluated. The expert opinion provided here has been corroborated by meta-analyzing the results of the retrieved studies.

EXPERT OPINION

Current evidence supports the beneficial role of lifestyle modifications in increasing T and improving sexual function as a function of weight loss. While dieting programs are associated with greater effects in younger populations, physical exercise has major effects in older ones. Among the dieting programs, a very low-calorie ketogenic diet shows the best results; aerobic or endurance physical exercise perform similarly. The advantages of functional hypogonadism in lifestyle modifications are empowered by the association with TRT. Therefore, TRT may be a valuable complementary strategy to increase muscle mass and facilitate physical exercise while improving sexual symptoms, thus favoring the motivation and compliance for lifestyle interventions.

Low testosterone at age 31 associates with maternal obesity and higher body mass index from childhood until age 46: A birth cohort study

BACKGROUND

Low testosterone (T) levels in men associate with increased risks of obesity, type 2 diabetes, metabolic syndrome, and cardiovascular diseases. However, most studies are cross-sectional with follow-up-time < 10 years, and data on early growth are limited.

OBJECTIVE

To compare prenatal factors and body mass index (BMI) development from birth to age 46 in relation to low T at age 31.

MATERIALS AND METHODS

Men with low T (T < 12.1 nmol/L, n = 132) and men with normal T at age 31 (n = 2561) were derived from the Northern Finland Birth Cohort 1966. Prenatal factors, longitudinal weight and height data from birth to age 14, and cross-sectional weight and height data at ages 31 and 46, and waist-hip-ratio (WHR) and T levels at age 31 were analyzed. Longitudinal modeling and timing of adiposity rebound (AR, second BMI rise at age 5-7 years) were calculated from fitted BMI curves. Results were adjusted for mother's pre-pregnancy BMI and smoking status, birth weight for gestational age, alcohol consumption, education level, smoking status, and WHR at age 31.

RESULTS

Neither gestational age nor birth weight was associated with low T at age 31; however, maternal obesity during gestation was more prevalent among men with low T (9.8% vs. 3.5%, adjusted aOR: 2.43 [1.19-4.98]). Men with low T had earlier AR (5.28 vs. 5.82, aOR: 0.73 [0.56-0.94]) and higher BMI (p < 0.001) from AR onward until age 46. Men with both early AR and low T had the highest BMI from AR onward.

CONCLUSIONS

In men, maternal obesity and early weight gain associate with lower T levels at age 31, independently of adulthood abdominal obesity. Given the well-known health risks related to obesity, and the rising prevalence of maternal obesity, the results of the present study emphasize the importance of preventing obesity that may also affect the later reproductive health of the offspring.

Does an increase in adipose tissue 'weight' affect male fertility? A systematic review and meta-analysis based on semen analysis performed using the WHO 2010 criteria

INTRODUCTION

Obesity negatively impact on the metabolism of sex hormones, leading to reduced testosterone serum levels. However, how the obesity could negatively impact on the overall gonadal function, particularly on male fertility, remained unclear so far.

OBJECTIVE

To systematically review evidences regarding the influence of body weight excess on the sperm production.

METHODS

A meta-analysis was conducted, searching all prospective and retrospective observational studies reporting male subjects older than 18 years old, with body weight excess from overweight to severe obesity were considered. Only studies using the V edition of the World Health Organization (WHO) manual for semen analysis interpretation were considered. No specific interventions were considered. Search was focused on studies comparing overweight/obese to normal weight subjects.

RESULTS

Twenty-eight studies were considered. Total sperm count and sperm progressive motility were significantly lower in overweight compared to normal weight subjects. Meta-regression analyses demonstrated that patients' age impacted on sperm parameters. Similarly, obese men showed lower sperm concentration, total sperm number, progressive and total motilities, and normal morphology lower than normal weight subjects. Reduced sperm concentration in obese men was influenced by age, smoking habit, varicocele, and total testosterone serum levels at meta-regression analyses.

CONCLUSIONS

The male potential fertility is reduced in subjects with increased body weight, compared to normal weight men. The higher was the increased body weight, the worst was the sperm quantity/quality. This result comprehensively included obesity among non-communicable risk factor for male infertility, shedding new lights on the negative impact of increased body weight on overall gonadal function.

Men, testosterone and Covid-19

Men have more severe Coronavirus disease 2019 (Covid-19) outcomes and higher mortality rates than women, and it was suggested that testosterone levels might promote severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and Covid-19 severity. However, clinical studies have not supported this theory. Studies have consistently shown that serum testosterone concentrations during acute Covid-19 in men are inversely proportional to the inflammatory cytokines and severity of illness. It is likely that lower testosterone concentrations in this setting are a result of acute Covid-19 illness on the hypothalamic-pituitary-testicular axis. Clinical trials that attempted to lower testosterone concentrations further or block androgen signaling acutely during Covid-19 in men did not result in improved Covid-19 outcomes. Additionally, pre-existing male hypogonadism, diagnosed before Covid-19 pandemic, was found to be a risk factor for hospitalization from Covid-19. In this review, we also discuss the preclinical and mechanistic studies that have evaluated the role of androgens in SARS-CoV-2 infection and illness. Finally, long-term consequences of Covid-19 on male reproductive health are reviewed. SARS-CoV-2 virus is known to infiltrate testis and induce orchitis in men, but it is unclear if Covid-19 leads to an increase in incidence of male hypogonadism.

Reduction of leptin levels during acute exercise is dependent on fasting but not on caloric restriction during chronic exercise: A systematic review and meta-analysis

BACKGROUND

The importance of leptin in controlling body mass has recently gained more attention. Its levels are directly associated with the amount of fat mass, but not necessarily dependent on it. Exercise has great potential in reducing leptin levels, however the response of exercise to this cytokine is still not well understood.

OBJECTIVE

The objective of the review was to analyze the effects of physical exercise on plasma leptin concentration, either acutely (post-exercise/training session) and/or after a training period (short- or long-term), as well as to investigate the existence of possible moderating variables.

METHODS

The studies included in this systematic review were published between 2005 and May 2023. Only peer-reviewed studies, available in English, performed with humans that evaluated the effects of any form of exercise on leptin levels were included. The search was conducted on May 03, 2023, in Embase (Elsevier), MEDLINE via PubMed®, and Web of Science (Core collection). The risk of bias in the included trials was assessed by the Physiotherapy Evidence Database tool, considering 11 questions regarding the methodology of each study with 10 questions being scored. The data (n, mean, and standard deviation) were extracted from included studies to perform random effects meta-analyses using standardized mean difference between the pre- and post-intervention effects.

RESULTS

Twenty-five studies (acute effect: 262 subjects; short- and long-term effect: 377 subjects) were included in this systematic review and meta-analysis. Short- and long-term physical exercise and caloric restriction plus exercise reduce plasma leptin levels, presenting statistically significant differences (p<0.001); as well as acute effect (p = 0.035), however the latter result was influenced by the pre-exercise meal as shown in the subgroup analysis. In this meta-analysis the effect of moderating factors on leptin reduction, not addressed by past reviews, is verified, such as the relationship with caloric restriction, exercise intensity and pre-exercise meal on acute responses.

CONCLUSION

Both acute and chronic exercise reduce leptin levels, yet the acute effect is dependent on the pre-exercise meal. In addition to having a long-term reduction in leptin levels, the minimum amount of weekly exercise to have a significant reduction in plasma leptin is 180 minutes of moderate-intensity exercise and 120 minutes of high-intensity exercise.

Examining the associations between testosterone and biomarkers as men age

OBJECTIVES

Testosterone concentrations in men decline with advancing age. However, the cause of the decline is yet to be fully elucidated. Therefore, the aims of this study were to examine the associations between chronic diseases such as obesity and type 2 diabetes mellitus (T2DM) with total testosterone (TT) and sex hormone-binding globulin (SHBG), using a large nationally-representative data set (National Health and Nutrition Examination Survey; NHANES).

METHODS

NHANES is a cross-sectional survey, physical examination, and laboratory evaluation of a nationally-representative sample of a non-institutionalized United States population. Male participants aged ≥18 years during the NHANES 2013-2014 and NHANES 2015-2016 survey periods were selected for this analysis. The analysis included the following data: body mass index (BMI), oral glucose tolerance test (OGTT), homeostatic model assessment of insulin resistance (HOMA-IR), insulin, glucose, and age.

RESULTS

An overweight or obese condition was significantly inversely associated with TT and SHBG, even after adjusting for other variables. Several variables associated with T2DM (OGTT, HOMA-IR, insulin, and glucose) were also inversely associated with TT; however, only the associations between OGTT and insulin with TT remained significant after adjusting for the other variables. Insulin and HOMA-IR levels were significantly inversely associated with SHBG; however, only the association between SHBG and pre-diabetic HOMA-IR levels remained significant after adjusting for the other variables. OGTT became significantly associated with SHBG after adjusting for the other variables. Age was significantly inversely associated with TT, but positively associated with SHBG, even after adjusting for other variables.

CONCLUSION

The results of the present study, which is the largest to date, indicate that a marker of obesity, BMI, and some markers of T2DM are both independently and significantly inversely associated with TT and SHBG.

The complex relation between obstructive sleep apnoea syndrome, hypogonadism and testosterone replacement therapy

Obstructive sleep apnoea syndrome (OSAS) is an under-recognized medical disease. The main risk factors for OSAS are male sex, older age, obesity, and metabolic syndrome, that are also associated with male hypogonadism (MH). Therefore, obesity has been classically identified as the most evident link between OSAS and MH. However, OSAS is per se linked to the development of MH by a combined effect of hypoxia, increased night-time awakenings, reduced sleep efficiency and fragmented sleep. Similarly, MH might represent a risk factor for OSAS, mainly related to sleep disturbances that are frequently associated with low testosterone. Data on testosterone replacement therapy (TRT) in patients with OSAS are limited. Nevertheless, TRT is generally contraindicated by guidelines in the presence of untreated or severe OSAS. TRT might in fact worse OSAS symptoms in different ways. Furthermore, OSAS has been proposed to be a risk factor for secondary polycythaemia and TRT might exacerbate polycythaemia. Therefore, TRT in hypogonadal men affected by untreated OSAS or severe OSAS should be considered with caution and in a personalised way. Nevertheless, the type and dosage of TRT should be considered, as short-term high-dose TRT might worsen OSAS, whereas long-term lower doses could eventually determine a clinical improvement of symptoms of OSAS. Here we reviewed the data on the association between OSAS, MH and TRT, including the opportunity of assessment of patients who develop signs and symptoms of OSAS during TRT by polysomnography.

Acquired Male Hypogonadism in the Post-Genomic Era-A Narrative Review

Although precision medicine took its first steps from genomic medicine, it has gone far beyond genomics, considering the full complexity of cellular physiology. Therefore, the present time can be considered as the "post-genomic era". In detail, proteomics captures the overall protein profile of an analyzed sample, whilst metabolomics has the purpose of studying the molecular aspects of a known medical condition through the measurement of metabolites with low molecular weight in biological specimens. In this review, the role of post-genomic platforms, namely proteomics and metabolomics, is evaluated with a specific interest in their application for the identification of novel biomarkers in male hypogonadism and in the identification of new perspectives of knowledge on the pathophysiological function of testosterone. Post-genomic platforms, including MS-based proteomics and metabolomics based on ultra-high-performance liquid chromatography-HRMS, have been applied to find solutions to clinical questions related to the diagnosis and treatment of male hypogonadism. In detail, seminal proteomics helped us in identifying novel non-invasive markers of androgen activity to be translated into clinical practice, sperm proteomics revealed the role of testosterone in spermatogenesis, while serum metabolomics helped identify the different metabolic pathways associated with testosterone deficiency and replacement treatment, both in patients with insulin sensitivity and patients with insulin resistance.

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.

Approach to the Patient: The Evaluation and Management of Men ≥50 Years With Low Serum Testosterone Concentration

Although testosterone replacement in men with classic hypogonadism due to an identified pathology of the hypothalamic-pituitary-testicular axis is uncontroversial, the role of testosterone treatment for men with age-related declines in circulating testosterone is unclear. This is due to the lack of large, long-term testosterone therapy trials assessing definitive clinical endpoints. However, men ≥50 years of age, particularly those who have a body mass index >25 kg/m2 and multiple comorbidities, commonly present with clinical features of androgen deficiency and low serum testosterone concentrations. Clinicians are faced with the question whether to initiate testosterone therapy, a difficult dilemma that entails a benefit-risk analysis with limited evidence from clinical trials. Using a case scenario, we present a practical approach to the clinical assessment and management of such men.

Plasma metabolomics in male primary and functional hypogonadism

Metabolomics proposes to unveil the molecular machinery involved in each specific disease by the comprehensive analysis of low-molecular-weight metabolites in a biological sample. This narrative mini-review analyzes previous studies applying ultra-high-performance liquid chromatography-high-resolution mass spectrometry (HRMS)-based metabolomics to highlight different metabolic pathways involved in male hypogonadism and testosterone replacement therapy, both in the case of insulin-sensitive patients with primary hypogonadism and in the case of insulin-resistant patients with functional hypogonadism. In functional hypogonadism, metabolomics revealed that different biochemical pathways are affected. In detail, glycolysis is the most important biochemical process involved in these patients. Glucose metabolism is fueled by amino acid degradation, and gluconeogenesis is widely stimulated. Some important pathways, including glycerol, are compromised. Furthermore, mitochondrial electron transport is influenced, namely, by a decrease in ATP production. On the contrary, beta-oxidation of short- and medium-chain fatty acids does not represent an energy source in hypogonadal patients. Both lactate and acetyl-CoA are converted into ketone bodies, which increased immensely. However, carnosine and β-alanine are greatly reduced. These metabolic changes are associated with increased fatigue and mental confusion. After testosterone replacement therapy, a complete restoration is achieved for only a part of the metabolites. It is of note that only in patients with functional hypogonadism treated with testosterone are ketone bodies produced at high levels, so the symptoms sometimes reported by these patients after the beginning of the therapy (difficulty in concentrating, depressed mood, brain fog, and memory impairment) might represent a specific "keto flu-like" syndrome, related to the metabolic ketonic state.

A cross-sectional analysis of the association between testosterone and biopsy-proven non-alcoholic fatty liver disease in men with obesity

PURPOSE

To study the association between testosterone and non-alcoholic fatty liver disease (NAFLD) since prior studies have reported inconsistent results.

METHODS

A retrospective analysis was performed including obese men who underwent a liver biopsy and a metabolic and hepatological work-up. Free testosterone (CFT) was calculated by the Vermeulen equation. The association between total testosterone (total T) and CFT on the one hand and NAFLD and fibrosis on the other hand was investigated and corrected for biasing factors such as metabolic parameters.

RESULTS

In total, 134 men (mean age 45 ± 12 years, median BMI 39.6 (25.0-64.9) kg/m²) were included. The level of total T and CFT did not significantly differ between NAFL and NASH and the stages of steatosis and ballooning. CFT was significantly lower in a higher stage of fibrosis (p = 0.013), not seen for total T and not persisting after controlling for the influence of BMI, HDL cholesterol and HOMA-IR. A higher stage of lobular inflammation was associated with a lower level of total T (p = 0.033), not seen for CFT and not persisting after controlling for the influence of visceral adipose tissue surface and HOMA-IR.

CONCLUSIONS

This is the second largest study investigating the association between testosterone and biopsy-proven NAFLD. No significant association between testosterone levels and NAFLD, and the different histological subgroups or fibrosis was seen. The lower level of CFT in a higher stage of fibrosis and the association between total T and lobular inflammation was driven by poor metabolic parameters.

Cardiometabolic indices predict hypogonadism in male patients with type 2 diabetes

PURPOSE

To evaluate in men with type 2 diabetes the association of cardiometabolic indices [Visceral Adiposity Index (VAI), Triglyceride Glucose Index (TyG), and lipid accumulation product (LAP)] with total testosterone (TT) levels, and their predictive cut-off values in identifying hypogonadism.

METHODS

265 consecutive men aged 40-70 years with type 2 diabetes performed an andrological evaluation; metabolic parameters and TT were determined. Receiver operating characteristic (ROC) curves were used to identify cut-off values of cardiometabolic indices in predicting low testosterone (TT < 12 nmol/l).

RESULTS

VAI, TyG, and LAP were negatively associated with TT levels. The prevalence of hypogonadism in men in the fourth quartiles of VAI, TyG, and LAP was ~ 70.0-75.0% compared to ~ 10.0-17.0% in men in the first quartiles (p < 0.001). The sensitivity and specificity of the three cardiometabolic indices in predicting TT < 12 nmol/l were significantly higher concerning BMI, waist circumference, lipid profile and HbA1c. Cut off values of VAI ≥ 3.985, TyG ≥ 4.925, and LAP ≥ 51.645 predict hypogonadism with good sensitivity and specificity.

CONCLUSION

This is the first study evaluating the association of VAI, TyG, and LAP with hypogonadism in men with type 2 diabetes. Alterations in these indices should direct the patients to andrological evaluation.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Impact of body composition analysis on male sexual function: A metabolic age study

Introduction

Metabolic Age (MetAge) and body composition analysis may reflect an individual's metabolic status, which is believed to influence male sexual and gonadal functions. Although erectile dysfunction (ED) and hypogonadism are increasingly prevalent with age, they are also detected among younger men. This study aims to assess the impact of MetAge and body composition on male sexual and gonadal status overall, and particularly in men younger than 40 years of age.

Methods

This was a cross-sectional study of 90 male healthcare workers, between the ages of 18-55, randomly selected based on their corporation numbers. In addition to Bioelectric Impedance Analysis, subjects were requested to fill the International Index of Erectile Function questionnaire (IIEF-5) and to provide an early morning serum testosterone (T) sample.

Results

The mean participants' age was 39.4 ± 9.4 years, MetAge was 45.54 ± 10.35 years, serum T level was 13.68 ± 4.49 nmol/L and BMI was 28.8 ± 4.7 kg/m2. Significant negative correlations were obtained between serum T, MetAge, body weight and fat composition. Significant negative correlations between the IIEF-5 score, MetAge, and fat composition, were only reported in subjects <40 years of age. Significantly lower T levels (p=0.002), significantly older MetAge (p=0.034), and higher BMI (p=0.044) and degree of obesity (p=0.042) were observed in participants <40 years with erectile dysfunction (ED) compared to their counterparts without ED.

Discussion

MetAge and body composition parameters significantly impact the androgenic state. ED in men <40 years is associated with lower T levels, older MetAge and higher BMI and degree of obesity.

[Testosterone treatment]

Male hypogonadism is a congenital or acquired disorder that exerts a negative influence on various organ functions and can massively impair the quality of life through the relative or absolute deficiency of testosterone. A variety of preparations are available for substitution treatment, which differ in administration form and intake interval. For the execution of testosterone treatment various guidelines exist with clear and practical instructions on the indications, contraindications, treatment procedure and monitoring. Of particular importance are cardiovascular aspects and diseases of the prostate gland, which underlines the central position of the urologist in the treatment.

Metformin, testosterone, or both in men with obesity and low testosterone: A double-blind, parallel-group, randomized controlled trial

BACKGROUND

Men with obesity tend to be insulin resistant and often have low-normal testosterone concentrations. We conducted a clinical trial aimed to evaluate potential therapeutic strategies for low testosterone in men with obesity.

METHODS

We did a 1-year, parallel, randomized, double-blind, placebo-controlled trial, where we evaluated the independent and combined effects of metformin and testosterone in 106 men with obesity, aged 18-50 years, who had low levels of testosterone and no diabetes mellitus. The primary outcome was change in insulin resistance, measured as Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) index. Secondary outcomes included changes in total and free serum testosterone, body composition, metabolic variables, erectile function, and health-related quality of life (HRQoL).

RESULTS

In the intention-to-treat analysis, the HOMA-IR index decreased significantly in all active groups compared to placebo (metformin -2.4, 95 % CI -4.1 to -0.8, p = 0.004; testosterone -2.7, 95 % CI -4.3 to -1.1, p = 0.001; combination -3.4, 95 % CI -5.0 to -1.8, p < 0.001). Combination therapy was not superior to testosterone alone in decreasing insulin resistance (-0.7, 95 % CI -2.3 to 0.9, p = 0.383). Only the combination of metformin plus testosterone significantly increased total and free testosterone concentrations, compared to placebo. No significant changes in body composition (except for a higher decrease in fat mass in the metformin and combination group), metabolic variables, erectile function, or HRQoL were found with any treatment.

CONCLUSIONS

Among men with obesity and low testosterone concentrations, the combination of metformin plus testosterone, metformin only, and testosterone only, compared to placebo, reduced insulin resistance with no evidence of additive benefit.

Diet and exercise interventions reduce serum asprosin and the corresponding hypothalamic– pituitary–gonad-axis dysfunction in obese men

Background: Asprosin (ASP) is a recently discovered adipocyte factor that participates in glucose metabolism and inflammatory reactions. Recent findings suggest that it may be involved in the regulation of sex hormone secretion in the hypothalamic-pituitary-gonad (HPG) axis, but no studies have been reported in related populations. The purpose of this study was to evaluate the changes in serum ASP levels in healthy men and obese men, as well as before and after exercise weight loss, and to investigate male hypogonadism, insulin resistance, inflammatory response, and relationships induced by ASP and obesity.

Methods: Thirty-eight young male volunteers were recruited and divided into a normal group (n = 20) and an obese group (n = 18) according to their body mass index. Fourteen of the obese men underwent a 14-week exercise and diet intervention (first 8 weeks of aerobic exercise at 60%–70% HR_max for 30–50 min/4 days a week). Beginning at week 9, the intensity was increased to 75% HR_max. Participants in the obese groups maintained a calorie-restricted diet throughout the study period.

Results: Serum ASP levels in the obese group were significantly higher than those in the normal group, and serum gonadotropin-releasing hormone (GnRh), luteinizing hormone (LH), and testosterone (T) levels were decreased. After 14 weeks of exercise and diet intervention, serum ASP decreased significantly, the levels of body weight, lean body weight, body fat rate, fasting insulin (FINS), homeostatic model assessment for insulin resistance, TNF-α, IL-6, and IL-1β decreased significantly, and the serum GnRH, LH, and T levels increased significantly. ASP was positively correlated with body weight, body fat percentage, FINS, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β and negatively correlated with relative lean body weight and serum LH and T levels.

Conclusion: The serum ASP levels were increased in obese men compared with those of normal weight individuals, resulting in a chronic inflammatory reaction, high serum insulin, and HPG axis injury. Fourteen weeks of exercise and diet intervention effectively alleviated this phenomenon. It has been speculated that ASP might regulate male reproductive function by regulating the inflammatory response and insulin sensitivity.

Gaps in the management of diabetes in Asia: A need for improved awareness and strategies in men's sexual health

Sexual dysfunction, which is defined as 'difficulty during any stage of the sexual encounter that prevents or impairs the individual or couple from enjoying sexual activity', is globally prevalent in males with prediabetes and diabetes. It is an early harbinger of cardiovascular diseases and has a profound impact on one's physical, mental, and social health. Among patients with either prediabetes or diabetes, the most common male sexual dysfunctions are hypogonadism, erectile dysfunction, and premature ejaculation. In Asia, although sexual health is an important factor of men's health, it is rarely discussed freely in real-life practice. Addressing sexual health in Asian males has always been challenging with multiple barriers at the levels of patients and health care providers. Therefore, the assessment and management of sexual dysfunction in routine clinical practice should involve a holistic approach with effective patient-provider communication. In this review, we discuss the epidemiology, pathophysiology, and the management of hypogonadism, erectile dysfunction, and premature ejaculation among males with either prediabetes or diabetes (type 1 and type 2), as well as the evidence gaps across Asia.

Aging, testosterone, and neuroplasticity: friend or foe?

Neuroplasticity or neural plasticity implicates the adaptive potential of the brain in response to extrinsic and intrinsic stimuli. The concept has been utilized in different contexts such as injury and neurological disease. Neuroplasticity mechanisms have been classified into neuroregenerative and function-restoring processes. In the context of injury, neuroplasticity has been defined in three post-injury epochs. Testosterone plays a key yet double-edged role in the regulation of several neuroplasticity alterations. Research has shown that testosterone levels are affected by numerous factors such as age, stress, surgical procedures on gonads, and pharmacological treatments. There is an ongoing debate for testosterone replacement therapy (TRT) in aging men; however, TRT is more useful in young individuals with testosterone deficit and more specific subgroups with cognitive dysfunction. Therefore, it is important to pay early attention to testosterone profile and precisely uncover its harms and benefits. In the present review, we discuss the influence of environmental factors, aging, and gender on testosterone-associated alterations in neuroplasticity, as well as the two-sided actions of testosterone in the nervous system. Finally, we provide practical insights for further study of pharmacological treatments for hormonal disorders focusing on restoring neuroplasticity.

Effects of a 3-Month Physical Training on Cortisol and Testosterone Responses in Women After Bariatric Surgery

PURPOSE

Although it is well established that physical activity (PA) may partially correct the metabolic and hormonal alterations observed in patients with obesity, knowledge of its impact after bariatric surgery (BS) remains poor. The purpose of this study was to assess the repercussions of physical training on cortisol and testosterone responses in post-BS women.

MATERIALS AND METHODS

According to a randomized clinical trial, a PA group (11 women) started a 3-month physical training 6 weeks after BS, whereas no specific activity was proposed to a control group (9 women). Submaximal exercise (i.e., 30 min at 60% VO₂peak) was performed by all subjects just before and after the 3-month period. Blood samples were taken at rest, after 10, 20, and 30 min of exercise and 10 min of passive recovery for cortisol and testosterone analyses. Blood glucose, blood lactate, and heart rate were assessed at the same time.

RESULTS

Before the program, a significant increase in cortisol, blood lactate, and heart rate was observed in all subjects during the submaximal exercise vs. rest, with no change in blood glucose and testosterone. After vs. before the 3-month period, no modification in any parameter was noted at rest in either group. However, during exercise, lack of cortisol increase and lower heart rate were found in the PA group only, with disappearance of the increase in blood lactate in both groups.

CONCLUSION

Our results show some beneficial effects of physical training on hormonal and physical parameters. Further studies are needed to determine the biological and clinical significance of these adaptations induced by physical training in women after BS.

Effect of SHBG Polymorphism on the Levels of Bioavailable Testosterone and Lipid Metabolism in Older Men of the Kazakh Population

This study is aimed at investigating the effect of SHBG (rs727428; rs10822184) and LPL (rs754493647) single nucleotide polymorphisms on the concentration of the bioavailable fraction of testosterone in older men. Materials and methods To study gene mutations, 417 residents of the East Kazakhstan region of Kazakh nationality were examined. The main group included 135 men with signs of hypogonadism (AMS 37-49), and the control group consisted of 282 healthy men (AMS 17-26) of the corresponding age (p = 0.5). Single nucleotide polymorphisms rs 727428 [C / T]; rs10822184 [T / C]; rs754493647 [T / C], was determined by the TaqMan method. Results Analysis of the rs727428 polymorphism has revealed that the TT allele (rs727428) has a lower level of albumin (p = 0.03), bioavailable testosterone (p = 0.04), and free testosterone (p = 0.6) than in carriers of the CC and CT genotypes. Also, it has shown a decrease in total testosterone (p = 0.001) and an increase in SHBG levels (p = 0.07) in men with the TT genotype of the rs727428 gene polymorphism. The rs10822184 polymorphism demonstrated an increase in triglyceride and LDL levels in TT genotype (p ≤ 0.04), in comparison with CC and CT genotypes. Conclusion It has been proven that rs727428 (p = 0.001) is associated with testosterone levels and therefore can determine the concentration of bioavailable testosterone. Decreased levels of bioavailable testosterone are a sign of male hypogonadism. This study confirms the effect of rs10822184 on LDL (p = 0.01) and triglyceride (p = 0.04) levels, but its association with androgen levels has not been proven. Our results may be of interest for understanding the etiology of early development of hypogonadism and lipid metabolism disorders in men. To confirm the conclusions, a more detailed study with a large sample of men from the Kazakh population may be required.

Association of age, hormonal, and lifestyle factors with the Leydig cell biomarker INSL3 in aging men from the EMAS (European Male Aging Study) cohort

BACKGROUND

Aging in men is accompanied by a broad range of symptoms, including sexual dysfunction, cognitive and musculo-skeletal decline, obesity, type 2 diabetes, cardiovascular disease and hypertension, organ degeneration/failure, and increasing neoplasia, some of which are associated with declining levels of Leydig cell-produced testosterone. High natural biological variance, together with multiple factors that can modulate circulating testosterone concentration, may influence its interpretation and clinical implications. INSL3 is a biomarker of Leydig cell function that might provide complementary information on testicular health and its downstream outcomes.

OBJECTIVES

To characterize INSL3 as a biomarker to assess gonadal status in aging men.

METHODS & MATERIALS

The large European multi-centre EMAS cohort of community-dwelling men was analysed to determine how INSL3 relates to a range of hormonal, anthropometric, and lifestyle parameters.

RESULTS & DISCUSSION

INSL3 declines cross-sectionally and longitudinally within individuals at approximately 15% per decade from age 40, unlike testosterone (1.9% per decade), which is partly compensated by increasing pituitary LH production. Importantly, lower INSL3 in younger men appears to persist with aging. Multiple regression analysis shows that, unlike testosterone, INSL3 is negatively dependent on LH and SHBG, and positively on FSH, suggesting a different mechanism of gonadotropic regulation. Circulating INSL3 is negatively associated with increased BMI or waist circumference, and with smoking, and unlike testosterone is not affected by weight loss in the obese. Geographic variation in mean INSL3 within Europe appears to be largely explained by differences in these parameters. The results allow the establishment of a European-wide reference range for INSL3 (95% confidence interval) adjusted for increasing age.

CONCLUSION

INSL3 is a constitutive biomarker of Leydig cell functional capacity, being a robust, reliably measurable peptide, not subject to the gonadotropin-dependent short-term regulation and within-individual variation of testosterone. This article is protected by copyright. All rights reserved.

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.

Association of Sex Hormones and Fat Distribution in Men with Different Obese and Metabolic Statuses

Purpose

Although several studies have explored the association of sex hormones with glucose metabolism, the association between sex hormones and body fat distribution, which is closely related to insulin resistance, has not been fully elucidated. We have tried to explore the relationship of testosterone (T) and estradiol (E2) with visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) mass in Chinese men with different obese and metabolic statuses.

Patients and Methods

A total of 128 men from the Health Management Center of the Second Xiangya Hospital, Central South University were collected and grouped in accordance with their obese and metabolic syndrome (MS) statuses: metabolically healthy non-overweight/obese men (MHNO), metabolically healthy overweight/obese men (MHO) and metabolically unhealthy overweight/obese men (MUO). Multiple regression analyses were performed to estimate contributions of sex hormones levels to the variations of body fat distribution and the contributions of body fat distribution to the variations of sex hormone levels.

Results

With fat mass parameters as independent variables, SAT had a strong negative association with T in MHNO (β = −2.772, P = 0.034), VAT was positively correlated with E2 in MHO (β = 22.269, P = 0.009), and SAT was negatively associated with T in MUO (β = −3.315, P = 0.010). With sex hormones as independent variables, E2 positively correlated with VAT (β = −176.259, P = 0.048), while T negatively correlated with VAT in MHO (β = 183.150, P = 0.029). In MUO, an inverse association of T with SAT was observed (β = −213.689, P = 0.021).

Conclusion

E2 and VAT had a mutual influence, thus resulting in a vicious circle, and the negative correlation between T and VAT may be related to the decrease of the MS occurrence in the MHO group. There were bi-directional relationships between sex hormones and fat distribution in men with different obese and metabolic statuses.

Trial Registration

Chinese Clinical Trial Registry, ChiCTR-EOC-16010194. Retrospectively registered.

A comprehensive review of the impact of obesity on plasma cell disorders

Multiple myeloma (MM) remains an incurable plasma cell malignancy. Although little is known about the etiology of MM, several metabolic risk factors such as obesity, diabetes, poor nutrition, many of which are modifiable, have been linked to the pathogenesis of numerous neoplasms including MM. In this article, we provide a detailed summary of what is known about the impact of obesity on the pathogenesis of MM, its influence on outcomes in MM patients, and discuss potential mechanisms through which obesity is postulated to influence MM risk and prognosis. Along with advancements in treatment modalities to improve survival in MM patients, focused efforts are needed to prevent or intercept MM at its earliest stages. The consolidated findings presented in this review highlight the need for clinical trials to assess if lifestyle modifications can reduce the incidence and improve outcomes of MM in high-risk populations. Data generated from such studies can help formulate evidence-based lifestyle recommendations for the prevention and control of MM.

Relationship between total testosterone, sex hormone-binding globulin levels and the severity of non-alcoholic fatty liver disease in males: a meta-analysis

BACKGROUND

In recent years, many studies have reported the relationship between non-alcoholic fatty liver disease (NAFLD) and sex hormones, especially total testosterone (TT) and sex hormone-binding globulin (SHBG). However, the relationship between sex hormones and the severity of NAFLD is still unclear.

METHODS

PubMed, Embase, Cochrane Library, Web of Science, WanFang, China National Knowledge Infrastructure and VIP databases were searched for relevant studies from inception to 31 August 2021. Values of weighted mean differences (WMDs) and odds ratios (ORs) with their 95% confidence intervals (CIs) were combined by Stata 12.0 software to evaluate the relationship between TT, SHBG and the severity of NAFLD in males.

RESULTS

A total of 2995 patients with NAFLD from 10 published cross-sectional studies were included for further analysis. The meta-analysis indicated that the moderate-severe group had a lower TT than the mild group in males with NAFLD (WMD: -0.35 ng/ml, 95% CI = -0.50 to -0.20). TT and SHBG were important risk factors of moderate-severe NAFLD in males (OR_TT = 0.79, 95% CI = 0.73 to 0.86; OR_SHBG = 0.22, 95% CI = 0.12 to 0.39; p < 0.001). Moreover, when the analysis was limited to men older than age 50, SHBG levels were lower in those with moderate-severe disease (WMD: -11.32 nmol/l, 95% CI = -14.23 to -8.40); while for men with body mass index (BMI) >27 kg/m², moderate-severe NAFLD had higher SHBG levels than those with mild disease (WMD: 1.20 nmol/l, 95% CI = -2.01 to 4.42).

CONCLUSION

The present meta-analysis shows that lower TT is associated with the severity of NAFLD in males, while the relationship between SHBG and severity of NAFLD is still to be further verified.

Sexual Dysfunction in Men and Women with Diabetes: A Reflection of their Complications?

BACKGROUND

Diabetes mellitus (DM), one of the worldwide leading causes of death, is associated with a plethora of micro- and macro-vascular complications which should be carefully investigated and, in case, treated in order to improve quality of life and reduce the risk of premature mortality.

OBJECTIVE

The study aimed to investigate and report current evidence with regard to the association between sexual dysfunction and diabetes.

METHODS

A detailed analysis of current literature has been performed on PubMed and Scholar in order to retrieve the most relevant findings pertaining to the study topic.

RESULTS

Female and male sexual dysfunction often occurs in diabetes; while cardiovascular complications are clearly involved, psychosexological factors, endocrine complications, and endothelial dysfunction all contribute to the pathogenesis of sexual dysfunctions. Psychological symptoms are seldom investigated, yet they should not be overlooked by the clinician; in fact, an interplay between sexual dysfunctions and depressive symptoms has been reported, and beneficial effects in both conditions might be obtained by adequate psychological support. Sexual dysfunctions can also act as early biomarkers of cardiovascular disease, a phenomenon frequently reported in men, in which erectile dysfunction predicts the development of coronary artery disease. Additionally, drug therapies can act in both directions, with treatments for diabetes possibly improving male sexual function and exerting beneficial effects for cardiovascular health being reported for pro-erectile drugs.

CONCLUSION

Sexual dysfunctions often occur in men and women with diabetes. Investigating micro- and macro-vascular complications might not be enough to prevent the development or worsening of any sexual dysfunction; endocrine and psychological assessments are therefore needed to provide the best chances for adequate treatment.

The Leydig cell biomarker INSL3 as a predictor of age-related morbidity: Findings from the EMAS cohort

BACKGROUND

Insulin-like peptide 3 (INSL3) is a constitutive hormone secreted in men by the mature Leydig cells of the testes. It is an accurate biomarker for Leydig cell functional capacity, reflecting their total cell number and differentiation status.

OBJECTIVES

To determine the ability of INSL3 to predict hypogonadism and age-related morbidity using the EMAS cohort of older community-dwelling men.

MATERIALS & METHODS

Circulating INSL3 was assessed in the EMAS cohort and its cross-sectional and longitudinal relationships to hypogonadism, here defined by testosterone (T) <10.5nmol/l, and a range of age-related morbidities determined by correlation and regression analysis.

RESULTS & DISCUSSION

While INSL3 is an accurate measure of primary hypogonadism, secondary and compensated hypogonadism also indicate reduced levels of INSL3, implying that testicular hypogonadism does not improve even when LH levels are increased, and that ageing-related hypogonadism may combine both primary and secondary features. Unadjusted, serum INSL3, like calculated free testosterone (cFT), LH, or the T/LH ratio reflects hypogonadal status and is associated with reduced sexual function, bone mineral density, and physical activity, as well as increased occurrence of hypertension, cardiovascular disease, cancer, and diabetes. Using multiple regression analysis to adjust for a range of hormonal, anthropometric, and lifestyle factors, this relationship is lost for all morbidities, except for reduced bone mineral density, implying that INSL3 and/or its specific receptor, RXFP2, may be causally involved in promoting healthy bone metabolism. Elevated INSL3 also associates with hypertension and cardiovascular disease. When unadjusted, INSL3 in phase 1 of the EMAS study was assessed for its association with morbidity in phase 2 (mean 4.3 years later); INSL3 significantly predicts 7 out of 9 morbidity categories, behaving as well as cFT in this regard. In contrast, total T was predictive in only 3 of the 9 categories.

CONCLUSION

Together with its low within-individual variance, these findings suggest that assessing INSL3 in men could offer important insight into the later development of disease in the elderly.

Obesity, Body Composition, and Sex Hormones: Implications for Cardiovascular Risk

Cardiovascular disease (CVD) continues to be the leading cause of death in adults, highlighting the need to develop novel strategies to mitigate cardiovascular risk. The advancing obesity epidemic is now threatening the gains in CVD risk reduction brought about by contemporary pharmaceutical and surgical interventions. There are sex differences in the development and outcomes of CVD; premenopausal women have significantly lower CVD risk than men of the same age, but women lose this advantage as they transition to menopause, an observation suggesting potential role of sex hormones in determining CVD risk. Clear differences in obesity and regional fat distribution among men and women also exist. While men have relatively high fat in the abdominal area, women tend to distribute a larger proportion of their fat in the lower body. Considering that regional body fat distribution is an important CVD risk factor, differences in how men and women store their body fat may partly contribute to sex-based alterations in CVD risk as well. This article presents findings related to the role of obesity and sex hormones in determining CVD risk. Evidence for the role of sex hormones in determining body composition in men and women is also presented. Lastly, the clinical potential for using sex hormones to alter body composition and reduce CVD risk is outlined. © 2022 American Physiological Society. Compr Physiol 12:1-45, 2022.

Anabolic-Androgenic Steroid Misuse: Mechanisms, Patterns of Misuse, User Typology, and Adverse Effects

Anabolic-androgenic steroids (AAS) encompass a broad group of natural and synthetic androgens. AAS misuse is highly prevalent on a global scale, with the lifetime prevalence of AAS misuse in males being estimated to be around 6%, with 15 to 25% of male gym attendees using it at any one time. AAS are associated with sudden cardiac death, neuropsychiatric manifestations, and infertility. The average AAS user is unlikely to voluntarily declare their usage to a physician, with around 1 in 10 actively engaging in unsafe injection techniques. The aim of this paper is to review the current evidence base on AAS with emphasis on mechanisms of action, adverse effects, and user profiles that are most likely to engage in AAS misuse. This paper also reviews terminologies and uses methods specific to the AAS user community.

[Testosterone replacement therapy and its relationship with hyperestrogenism and obesity. Problems of laboratory diagnostics of hyperestrogenism]

Testosterone replacement therapy (TRT) is one of the most effective and common treatments for testosterone deficiency today. It is often prescribed, focusing only on the level of testosterone and the presence of patient complaints about a decrease in sexual function. Quite rarely, doctors additionally assess the level of estradiol and, as a consequence, the initial presence of a symptom of hyperestrogenism. One of the likely consequences of the appointment of TRT may be an excess of estradiol, the excess formation of which is associated with the enzyme aromatase, which converts testosterone into estradiol. Despite the availability of laboratory determination of the level of estradiol, the result may not always coincide with the clinical picture, one of the reasons is the difference in the methods for determining the level of estradiol in each laboratory, there is no single standard or «reference» today. This article describes the evolution of TRT, and also focuses on the variability of estradiol levels from laboratory to laboratory, and explains in detail why the assessment of estradiol over time should be carried out in only one laboratory. A systematic literature search was carried out in the databases Medline, Scopus, Web of Science and Elibrary, CyberLeninka.The purpose of our review was the need to engage the attention of specialists to the problem of hyperestrogenism, the not always justified prescription of TRT in patients with obesity, hypogonadism and hyperestrogenism, as well as to the problem of laboratory diagnosis of hyperestrogenism, which is acute not only in our country, but all over the world.

The Sexual Long COVID (SLC): Erectile Dysfunction as a Biomarker of Systemic Complications for COVID-19 Long Haulers

Introduction

Long term complications of COVID-19, the disease caused by the SARS-CoV-2, involve many organ systems, dramatically worsening the quality of life, and finally contributing to impaired physical functioning. Despite the presence of well-identified pathogenetic mechanisms, the effect of “Long COVID” on sexual health has been only marginally addressed.

Objectives

To provide coverage of the current literature on long COVID, its epidemiology, pathophysiology, and relevance for erectile function. Methods. Comprehensive review of literature pertaining to the epidemiology and pathophysiology of long COVID, and its relevance for erectile function.

Results

Symptoms of long COVID are highly prevalent and involve almost all systems of the human body, with a plethora of clinical manifestations which range from minor nuisances to life-threatening conditions. “Brain fog” and fatigue are the most common complaints, although other neuropsychiatric complications, including sensory dysfunctions, anxiety, depression, and cerebrovascular events have also been reported. The respiratory and cardiovascular systems are also affected, with dyspnea, pulmonary fibrosis, endothelial dysfunction, and myocarditis occurring in some COVID long haulers. A subset of patients might develop endocrine manifestations, including onset of diabetes, thyroid dysfunction, and hypogonadism. Overall, long COVID features many complications which can impair erectile function by multiple pathogenetic mechanisms, and which could require tailored treatment: (i) careful investigation and management from the sexual medicine expert are therefore much needed, (ii) and future research on this topic is warranted.

Conclusion

in COVID-19 long haulers, several complications can adversely affect erectile function which, upon future tailored studies, could be used as biomarker for the severity of the long COVID disease and for its follow-up.

Sansone A, Mollaioli D, Limoncin E et al. The Sexual Long COVID (SLC): Erectile Dysfunction as a Biomarker of Systemic Complications for COVID-19 Long Haulers. Sex Med Rev 2022;10:271–285.

The Mechanisms and Management of Age-Related Oxidative Stress in Male Hypogonadism Associated with Non-communicable Chronic Disease

Androgens have diverse functions in muscle physiology, lean body mass, the regulation of adipose tissue, bone density, neurocognitive regulation, and spermatogenesis, the male reproductive and sexual function. Male hypogonadism, characterized by reduced testosterone, is commonly seen in ageing males, and has a complex relationship as a risk factor and a comorbidity in age-related noncommunicable chronic diseases (NCDs), such as obesity, metabolic syndrome, type 2 diabetes, and malignancy. Oxidative stress, as a significant contributor to the ageing process, is a common feature between ageing and NCDs, and the related comorbidities, including hypertension, dyslipidemia, hyperglycemia, hyperinsulinemia, and chronic inflammation. Oxidative stress may also be a mediator of hypogonadism in males. Consequently, the management of oxidative stress may represent a novel therapeutic approach in this context. Therefore, this narrative review aims to discuss the mechanisms of age-related oxidative stress in male hypogonadism associated with NCDs and discusses current and potential approaches for the clinical management of these patients, which may include conventional hormone replacement therapy, nutrition and lifestyle changes, adherence to the optimal body mass index, and dietary antioxidant supplementation and/or phytomedicines.

Examining the effects of calorie restriction on testosterone concentrations in men: a systematic review and meta-analysis

CONTEXT

Testosterone concentrations decline with age, and lower testosterone concentrations are associated with several morbidities, including sexual dysfunction, obesity, type 2 diabetes mellitus (T2DM), and metabolic syndrome.

OBJECTIVE

Because dietary habits play a critical role in weight regulation and T2DM management, the aim of this systematic review and meta-analysis was to summarize and critically evaluate the evidence from randomized controlled trials to determine the effects of calorie restriction (CR) on testosterone concentrations in men.

DATA SOURCES

A literature search was conducted across 4 databases, from their inception until March 2020.

DATA EXTRACTION

The screening and data extraction were completed by 2 authors independently, and in a blinded manner, according to a priori inclusion and exclusion criteria.

DATA ANALYSIS

Of the 4198 studies identified from the initial search, 7 randomized controlled trials were included for data extraction. Significant increases in total testosterone concentrations were reported in 3 of 4 studies in which CR was examined with overweight or obese men, compared with the control groups. Significant decreases in total testosterone concentrations were reported in 2 of 3 studies in which the effects of CR were examined with normal-weight, healthy men, compared with the control groups. In all 4 studies that examined the effect of CR on sex hormone-binding globulin concentrations, the intervention significantly increased sex hormone-binding globulin concentrations compared with that of the control groups irrespective of body composition.

CONCLUSION

This systematic review and meta-analysis provide some evidence that CR affects testosterone concentrations in men and this effect depends on their body mass index. PROSPERO registration no. CRD42020173102.

Dietary tomato inhibits angiogenesis in TRAMP prostate cancer but is not protective with a Western-style diet in this pilot study

Prostate cancer (PCa) remains the second most diagnosed cancer worldwide. Higher body weight is associated with chronic inflammation, increased angiogenesis, and treatment-resistant tumor phenotypes. Dietary tomato reduces PCa risk, which may be due to tomato inhibition of angiogenesis and disruption of androgen signaling. This pilot study investigated the interplay between tomato powder (TP), incorporated into control (CON) and obesogenic (OB) diets, and PCa tumor growth and blood perfusion over time in a transgenic model of PCa (TRAMP). Ultrasound microvessel imaging (UMI) results showed good agreement with gold-standard immunohistochemistry quantification of endothelial cell density, indicating that this technique can be applied to non-invasively monitor tumor blood perfusion in vivo. Greater body weight was positively associated with tumor growth. We also found that TP significantly inhibited prostate tumor angiogenesis but that this inhibition differentially affected measured outcomes depending on CON or OB diets. TP led to reduced tumor growth, intratumoral inflammation, and intratumoral androgen-regulated gene expression (srd5a1, srd5a2) when incorporated with the CON diet but greater tumor growth and intratumoral gene expression when incorporated with the OB diet. Results from this study show that protective benefits from dietary tomato are lost, or may become deleterious, when combined with a Western-style diet.

Melatonin ameliorates endocrine dysfunction and defective sperm integrity associated with high-fat diet-induced obesity in male Wistar rats

Obesity (OBS) has been established as a link to male hypogonadism with consequent infertility. Previous studies have shown that melatonin (MEL) modulates hypothalamic-pituitary-gonadal function. The present study therefore investigated the hypothesis that MEL supplementation would attenuate spermatogenic and steroidogenic dysfunctions associated with obesity induced by high-fat diet (HFD). Twenty-four adult male Wistar rats (n = 6/group) were used: control group received vehicle (normal saline), obese group received 40% high-fat diet and distilled water, MEL-treated group received MEL (4 mg/kg), and OBS + MEL group received MEL and 40% HFD and the treatment lasted for 12 weeks. HFD caused increased body weight, glucose intolerance, plasma triglyceride and low-density lipoprotein cholesterol/ very low-density lipoprotein cholesterol and malondialdehyde, as well as decreased antioxidant capacity, high-density lipoprotein cholesterol, gonadotrophin-releasing hormone, follicle-stimulating hormone and testosterone and altered sperm parameters. However, all these alterations were attenuated when supplemented with MEL. Taken together, these results indicate that HFD exposure causes endocrine dysfunction and disrupted sperm parameters in obese animals, which are accompanied by lipid peroxidation/defective antioxidant capacity. In addition, the present results suggest that melatonin supplementation restores endocrine function and sperm integrity in obese rat model by suppression of oxidative stress-dependent mechanism.

Approach to Obesity in the Older Population

Until recently, weight loss in older obese people was feared because of ensuing muscle loss and frailty. Facing overall increasing longevity, high rates of obesity in older individuals (age ≥ 65 years) and a growing recognition of the health and functional cost of the number of obesity years, abetted by evidence that intentional weight loss in older obese people is safe, this approach is gradually, but not unanimously, being replaced by more active principles. Lifestyle interventions that include reduced but sufficient energy intake, age-adequate protein and micronutrient intake, coupled with aerobic and resistance exercise tailored to personal limitations, can induce weight loss with improvement in frailty indices. Sustained weight loss at this age can prevent or ameliorate diabetes. More active steps are controversial. The use of weight loss medications, particularly glucagon-like peptide-1 analogs (liraglutide as the first example), provides an additional treatment tier. Its safety and cardiovascular health benefits have been convincingly shown in older obese patients with type 2 diabetes mellitus. In our opinion, this option should not be denied to obese individuals with prediabetes or other obesity-related comorbidities based on age. Finally, many reports now provide evidence that bariatric surgery can be safely performed in older people as the last treatment tier. Risk-benefit issues should be considered with extreme care and disclosed to candidates. The selection process requires good presurgical functional status, individualized consideration of the sequels of obesity, and reliance on centers that are highly experienced in the surgical procedure as well as short-term and long-term subsequent comprehensive care and support.

Changes in white adipose tissue gene expression in a randomized control trial of dieting obese men with lowered serum testosterone alone or in combination with testosterone treatment

PURPOSE

The aim of this study was to determine early weight loss-associated changes in subcutaneous abdominal white adipose tissue (WAT) gene expression in obese men with lowered serum testosterone by RNA next-generation sequencing.

METHODS

Fourteen men, mean age (IQR) 51.6 years (43.4-54.5), BMI 38.3 kg/m² (34.6-40.8) and total testosterone 8.4 nmol/L (7.5-9.5) provided subcutaneous WAT samples at baseline and after 2 weeks of a very low energy diet.

RESULTS

Body weight loss was similar in participants receiving testosterone (n = 6), -5.27 kg [95% CI -6.17; -4.26], and placebo (n = 8), -4.57 kg [95% CI -6.10; -3.55], p = 0.86. In placebo-treated men, of the 14,410 genes expressed in subcutaneous WAT, four genes, Angiopoietin-like 4, Semaphorin 3 G, Neuropilin 2 and Angiopoietin 4, were upregulated (adjusted false discovery rate P < 0.05). In an exploratory analysis comparing men receiving testosterone and placebo, the most-upregulated gene in the testosterone group (exploratory p < 0.0005) was the neuropeptide y receptor 2.

CONCLUSIONS

In obese men, dieting is associated with upregulation of WAT-expressed Angiopoietin-like 4, a secreted protein that regulates lipid metabolism, Semaphorin 3 G, a proposed adipocyte differentiation factor and secreted adipokine, and its receptor Neuropilin 2, as well as Angiopoietin 4, a vascular integrity factor. In an exploratory analysis, testosterone was associated with the upregulation of neuropeptide y receptor 2, a receptor involved in appetite regulation. Further studies are needed to confirm these observations and their potential biological implications.

TRIAL REGISTRATION

clinicaltrials.gov, Identifier NCT01616732, Registration date: June 8, 2012.

Impacts of Immunometabolism on Male Reproduction

The physiological process of male reproduction relies on the orchestration of neuroendocrine, immune, and energy metabolism. Spermatogenesis is controlled by the hypothalamic-pituitary-testicular (HPT) axis, which modulates the production of gonadal steroid hormones in the testes. The immune cells and cytokines in testes provide a protective microenvironment for the development and maturation of germ cells. The metabolic cellular responses and processes in testes provide energy production and biosynthetic precursors to regulate germ cell development and control testicular immunity and inflammation. The metabolism of immune cells is crucial for both inflammatory and anti-inflammatory responses, which supposes to affect the spermatogenesis in testes. In this review, the role of immunometabolism in male reproduction will be highlighted. Obesity, metabolic dysfunction, such as type 2 diabetes mellitus, are well documented to impact male fertility; thus, their impacts on the immune cells distributed in testes will also be discussed. Finally, the potential significance of the medicine targeting the specific metabolic intermediates or immune metabolism checkpoints to improve male reproduction will also be reassessed.

Androgen Misuse and Abuse

Androgens are potent drugs requiring prescription for valid medical indications but are misused for invalid, unproven, or off-label reasons as well as being abused without prescription for illicit nonmedical application for performance or image enhancement. Following discovery and first clinical application of testosterone in the 1930s, commercialization of testosterone and synthetic androgens proliferated in the decades after World War II. It remains among the oldest marketed drugs in therapeutic use, yet after 8 decades of clinical use, the sole unequivocal indication for testosterone remains in replacement therapy for pathological hypogonadism, organic disorders of the male reproductive system. Nevertheless, wider claims assert unproven, unsafe, or implausible benefits for testosterone, mostly representing wishful thinking about rejuvenation. Over recent decades, this created an epidemic of testosterone misuse involving prescription as a revitalizing tonic for anti-aging, sexual dysfunction and/or obesity, where efficacy and safety remains unproven and doubtful. Androgen abuse originated during the Cold War as an epidemic of androgen doping among elite athletes for performance enhancement before the 1980s when it crossed over into the general community to become an endemic variant of drug abuse in sufficiently affluent communities that support an illicit drug industry geared to bodybuilding and aiming to create a hypermasculine body physique and image. This review focuses on the misuse of testosterone, defined as prescribing without valid clinical indications, and abuse of testosterone or synthetic androgens (androgen abuse), defined as the illicit use of androgens without prescription or valid indications, typically by athletes, bodybuilders and others for image-oriented, cosmetic, or occupational reasons.

Testicular volume and clinical correlates of hypothalamic-pituitary-testicular function: A cross-sectional study in obese men

The aim of this study was to determine whether testicular volume is correlated with clinical and biochemical markers of hypothalamic–pituitary–testicular (HPT) axis function. This was a cross-sectional substudy of a larger randomized controlled trial including obese men, body mass index (BMI) ≥30 kg m⁻², with a total testosterone level <12 nmol l⁻¹. Testicular volume was measured by orchidometer, testosterone by liquid chromatography/tandem mass spectrometry, and body composition by dual-energy X-ray absorptiometry. Men completed the Aging Males' Symptoms (AMS) score, International Index of Erectile Function-5 (IIEF-5), physical function, and handgrip dynamometer testing. Eighty-nine men participated with a median (interquartile range [IQR]) age of 53.1 (47.6, 59.2) years, BMI of 37.0 (34.6, 40.5) kg m⁻², and a total testosterone of 7.0 (6.1, 7.9) nmol l⁻¹. Median testicular volume was 18 (IQR: 10, 20) ml. Testicular volume was negatively correlated with BMI (τ = −0.1952, P = 0.010) and total fat mass (τ = −0.2115, P = 0.005) independent of age and testosterone. When BMI, testosterone, sex hormone-binding globulin (SHBG), and luteinizing hormone (LH) were present in a multivariable model, only BMI (-0.38 ml change in testicular volume per 1 kg m^-2 BMI; 95% CI: −0.74, −0.02; P = 0.04) and LH (-0.92 ml change in testicular volume per 1 IU l^-1 LH; 95% CI: −1.75, −0.095; P = 0.03) remained independent significant predictors of testicular volume. Testicular volume was positively correlated with IIEF-5 (τ = 0.2092, P = 0.021), but not related to handgrip strength, physical function tests, or AMS. In obese men, testicular volume is inversely and independently associated with measures of adiposity, but not with most clinical or biochemical markers of HPT axis action. From a clinical perspective, this suggests that obesity might compromise the reliability of reduced testicular volume as a sign of androgen deficiency in men.