Inverse association of testosterone and the metabolic syndrome in men is consistent across race and ethnic groups

Sex difference in human diseases: mechanistic insights and clinical implications

Sex characteristics exhibit significant disparities in various human diseases, including prevalent cardiovascular diseases, cancers, metabolic disorders, autoimmune diseases, and neurodegenerative diseases. Risk profiles and pathological manifestations of these diseases exhibit notable variations between sexes. The underlying reasons for these sex disparities encompass multifactorial elements, such as physiology, genetics, and environment. Recent studies have shown that human body systems demonstrate sex-specific gene expression during critical developmental stages and gene editing processes. These genes, differentially expressed based on different sex, may be regulated by androgen or estrogen-responsive elements, thereby influencing the incidence and presentation of cardiovascular, oncological, metabolic, immune, and neurological diseases across sexes. However, despite the existence of sex differences in patients with human diseases, treatment guidelines predominantly rely on male data due to the underrepresentation of women in clinical trials. At present, there exists a substantial knowledge gap concerning sex-specific mechanisms and clinical treatments for diverse diseases. Therefore, this review aims to elucidate the advances of sex differences on human diseases by examining epidemiological factors, pathogenesis, and innovative progress of clinical treatments in accordance with the distinctive risk characteristics of each disease and provide a new theoretical and practical basis for further optimizing individualized treatment and improving patient prognosis.

Predictive power of lipid-related indicators for testosterone deficiency: a comparative analysis, NHANES 2011-2016

BACKGROUND

Studies have shown that lipid-related indicators are associated with testosterone deficiency. However, it is difficult to determine which indicator is the most accurate predictor of testosterone deficiency. We aimed to identify the lipid-related indicators most predictive of testosterone deficiency in adults in the United States.

METHODS

This observational research was conducted on a population aged ≥ 20 years. By plotting the receiver operating characteristic curve (ROC) and obtaining the corresponding area under the curve (AUC) value, we assessed the predictive capacity of TyG, WTI, LAP, and VAI for testosterone deficiency. We compared the area under the curve (AUC) values of these measures to determine if there were any statistically significant differences. The relationship between lipid-related indices and testosterone hormones was investigated using regression modeling, eXtreme Gradient Boosting (XGBoost) modeling, and sensitivity analysis.

RESULTS

A total of 3,272 eligible participants were included in the study. Testosterone deficiency was found to exist in 20.63% of the participants. Subjects with higher lipid-related markers were more likely to have lower testosterone levels. LAP was the best predictor of testosterone deficiency in ROC analysis over other indicators (AUC = 0.7176, (95% CI: 0.6964-0.7389)).

CONCLUSION

LAP is the most straightforward and convenient indicator for identifying testosterone deficiency in clinical practice.

Blood pressure responses to testosterone therapy are amplified by hematocrit levels in opioid-induced androgen deficiency: a double-blind, randomized, placebo-controlled trial

Our study aimed to examine the effect of testosterone replacement therapy (TRT) on blood pressure in opioid-treated men with relative hypogonadism, and whether the effect of TRT on blood pressure was modified by body composition, red blood cell levels, or carotid intima media thickness. Men (over 18 years old) receiving opioid treatment and total testosterone less than 12 nmol were randomly assigned to receive either TRT or placebo. Baseline and 6-month measurements included anthropometric measurements, office blood pressure (OBPM), 24-h ambulatory blood pressure, blood samples, and carotid ultrasound. The mean systolic OBPM increased by 6.2 mmHg (0.2-12.1) in the TRT group and decreased by 7.0 mmHg (1.0-15.1) in the placebo group, with a mean difference of 13.2 mmHg (3.4-23.1), P  = 0.01. In the TRT group, a 10 mmHg increase in systolic OBPM was associated with an increase in hematocrit of 0.3% points (0.1-0.5) ( P  = 0.01), whereas no association was observed in the placebo group ( P  = 0.266). Daytime SBP showed a nonsignificant increase of 5.2 mmHg (-1.7, 12.1) ( P  = 0.134) in the TRT group compared to that in the placebo group. However, the impact of TRT on the increase in daytime ambulatory blood pressure was significantly accentuated by baseline values of BMI, hematocrit, and hemoglobin. In conclusion, TRT was associated with higher OBPM compared to placebo, and the increase in blood pressure was linked to higher hematocrit during TRT. Our data suggest that men with opioid-induced androgen deficiency, particularly those with obesity or red blood cell levels in the upper normal range, are more susceptible to increased daytime SBP during TRT.

Association of metabolic syndrome and sarcopenia with all-cause and cardiovascular mortality: a prospective cohort study based on the NHANES

Background

Metabolic syndrome (MetS) and sarcopenia (SP) have emerged as significant public health concerns in contemporary societies, characterized by shared pathophysiological mechanisms and interrelatedness, leading to profound health implications. In this prospective cohort study conducted within a US population, we aimed to examine the influence of MetS and SP on all-cause and cardiovascular mortality.

Methods

This study analyzed data from the National Health and Nutrition Examination Survey (NHANES) III for the years 1999-2006 and 2011-2018, and death outcomes were ascertained by linkage to National Death Index (NDI) records through December 31, 2019. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for all-cause and cardiovascular mortality. In addition, subgroup and sensitivity analyses were conducted to test the robustness of the results.

Results

Over a median follow-up period of 13.3 years (95% CI: 12.8-13.8), 1714 deaths were observed. The groups characterized by MetS-/SP+, MetS+/SP-, and MetS+/SP+ exhibited higher all-cause mortality rates in comparison to the MetS-/SP- group, with the MetS+/SP+ group (HR 1.76, 95% CI: 1.37-2.25) displaying the highest all-cause mortality. Increased cardiovascular mortality was observed in the MetS+/SP- (HR 1.84, 95% CI: 1.24-2.72), and MetS+/SP+ groups (HR 2.39, 95% CI: 1.32-4.35) compared to the MetS-/SP- group, whereas it was not statistically significant in the MetS-/SP+ group. However, among males and individuals aged < 60, the presence of both MetS and SP (MetS+/SP+ group) was found to be significantly associated with a higher risk of all-cause and cardiovascular mortality.

Conclusion

The coexistence of MetS and SP increased the risk of all-cause and cardiovascular mortality, particularly in males and in nonelderly populations. Individuals with either MetS or SP may require more careful management to prevent the development of other diseases and thereby reduce mortality.

Polymorphisms −374 T/A and −429 T/C of the Receptor for Advanced Glycation End-Products (RAGE) and Serum Levels of RAGE (sRAGE) Are Not Associated with Metabolic Syndrome

RAGE is a multi-ligand transmembrane glycoprotein that promotes biological signals associated with inflammatory responses and degenerative diseases. sRAGE is a soluble variant, proposed as an inhibitor of RAGE activity. −374 T/A and −429 T/C polymorphisms of the advanced glycation end products receptor AGER gene are associated with the development of some diseases, such as type of cancer, cardiovascular disease, and micro and macrovascular disease in diabetes among others but their role in metabolic syndrome (MS) is still unknown. We studied 80 healthy men without MS, and 80 men with MS according to the harmonized criteria. −374 T/A and −429 T/C polymorphisms were genotyped by RT-PCR, and sRAGE was measured by ELISA. Allelic and genotypic frequencies did not differ between Non-MS and MS groups (−374 T/A p = 0.48, p = 0.57 and −429 T/C p = 0.36, p = 0.59). Significant differences were found in fasting glucose levels and diastolic blood pressure among the genotypes of the −374 T/A polymorphism in the Non-MS group (p < 0.01 and p = 0.008). Glucose levels were different between −429 T/C genotypes in the MS group (p = 0.02). sRAGE levels were similar in both groups, but in the Non-MS group showed a significant difference between individuals with only 1 or 2 components of the metabolic syndrome (p = 0.047). However, no associations of any SNP with MS were found (recessive model p = 0.48, dominant model p = 0.82 for −374 T/A; recessive model p = 0.48, dominant model p = 0.42 for −429 T/C). −374 T/A and −429 T/C polymorphisms are not associated with MS in Mexican population and have no influence on serum sRAGE levels.

The occurrence of hypogonadotropic hypogonadism in Chinese men with type 2 diabetes

CONTEXT

The previous studies showed that hypogonadotropic hypogonadism (HH) occurred commonly in men with type 2 diabetes. However, since all the cohorts tested were from American and European studies, the occurrence of HH/nongonadal illness (NGI) in Chinese populations is unclear.

OBJECTIVE

The study aimed to explore the occurrence of HH/NGI in Chinese men with type 2 diabetes. Furthermore, the correlative factors and predictors of hypogonadism were investigated.

DESIGN

We conducted a cross-sectional study of 637 Chinese men with type 2 diabetes aged 20-75 years in our clinic. The prevalence of HH/NGI was investigated by measuring serum total testosterone (TT), sex hormone-binding globulin (SHBG), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the enrolled subjects. Free testosterone (FT) was calculated by using SHBG and TT levels and hypogonadism was defined as TT lower than 10.4 nmol/L and calculated FT (cFT) lower than 0.225 nmol/L. The LH cut-off value for defining HH/NGI was 9.4 mIU/ml.

RESULTS

The results suggested that 31.9% of male Chinese type 2 diabetes patients had hypogonadism and 26.5% of subjects in our cohort were determined as HH/NGI. The occurrence of hypogonadism was markedly correlated with body mass index (BMI). There was a significant association between TT, cFT and SHBG levels with BMI. TT levels are inversely correlated with BMI and homeostasis model assessment-estimated insulin resistance (HOMA-IR) while positively related with SHBG. The cFT levels were inversely correlated with age, LH, FSH, BMI and HOMA-IR. Multiple regression analysis suggested that SHBG, BMI and HOMA-IR were significant predictors of TT and cFT.

CONCLUSION

Our present study offered the first evidence that the occurrence of HH/NGI in Chinese male type 2 diabetes was 26.5%. TT and cFT were significantly correlated with BMI, SHBG and HOMA-IR in Chinese men with type 2 diabetes.

Leukemia inhibitory factor-receptor signalling negatively regulates gonadotrophin-stimulated testosterone production in mouse Leydig Cells

Testicular Leydig cells (LCs) are the principal source of circulating testosterone in males. LC steroidogenesis maintains sexual function, fertility and general health, and is influenced by various paracrine factors. The leukemia inhibitory factor receptor (LIFR) is expressed in the testis and activated by different ligands, including leukemia inhibitory factor (LIF), produced by peritubular myoid cells. LIF can modulate LC testosterone production in vitro under certain circumstances, but the role of consolidated signalling through LIFR in adult LC function in vivo has not been established. We used a conditional Lifr allele in combination with adenoviral vectors expressing Cre-recombinase to generate an acute model of LC Lifr-KO in the adult mouse testis, and showed that LC Lifr is not required for short term LC survival or basal steroidogenesis. However, LIFR-signalling negatively regulates steroidogenic enzyme expression and maximal gonadotrophin-stimulated testosterone biosynthesis, expanding our understanding of the intricate regulation of LC steroidogenic function.

Testosterone, Diabetes Risk, and Diabetes Prevention in Men

Middle-aged and older men with lower testosterone concentrations are more likely to have or to develop metabolic syndrome and type 2 diabetes. Central adiposity is a risk factor for metabolic syndrome and diabetes and predisposes to lower testosterone concentrations. Conversely, testosterone treatment reduces fat mass and insulin resistance. In a randomized controlled trial of 1007 men with either impaired glucose tolerance or newly diagnosed type 2 diabetes, 2 years of testosterone treatment on a background of lifestyle intervention reduced the risk of type 2 diabetes by 40%; this demonstrates the potential utility for testosterone pharmacotherapy to prevent diabetes in men.

Relationship Between Serum Testosterone Levels and Kidney Stones Prevalence in Men

BACKGROUND

The role of serum testosterone levels in male renal stone formation remains controversial. This study aimed to evaluate the relationship between serum testosterone levels and kidney stone prevalence in males.

METHODS

We conducted a cross-sectional study based on the data from the National Health and Nutrition Examination Survey 2011-2016, which included 6,633 male participants, to investigate the association between testosterone levels and the prevalence of kidney stones.

RESULTS

In this study, using the highest quartile of serum testosterone as a reference, a logistic regression model adjusted for confounders in all participants showed that the first quartile (OR: 1.375, p = 0.016), the second quartile (OR: 1.348, p = 0.021), and the third quartile (OR: 1.472, p = 0.003) of testosterone significantly increased kidney stone risks. In the 41-60 age group, the ORs of kidney stone risk in the first, second, and third of serum testosterone were 1.904 (P = 0.005), 1.599 (P = 0.040), and 1.734 (P = 0.015), respectively. This trend can also be found in the 61-80-year group, except in the first quartile of serum testosterone (OR: 1.169, P = 0.436). Adjusted smoothed curves suggest a non-linear relationship between the 8 quantiles of serum testosterone and the risk of kidney stones in all participants and the 61-80 age group and a significant negative relationship in the 41-60 age group (OR: 0.921, P = 0.0193). But no correlation was seen in the 20-40 group.

CONCLUSIONS

Serum testosterone levels were significantly inversely associated with the prevalence of kidney stones in men over 40 years of age, but no correlation was seen in the 20-40 group. The role of testosterone in stone formation should be redefined, and its effect should be further verified.

Prevalences of metabolic syndrome and its sex-specific association with socioeconomic status in rural China: a cross-sectional study

Background

Few studies have reported the prevalence of metabolic syndrome (MS) and examined relationships between socioeconomic status and MS in rural China. This study aimed to evaluate the prevalence of MS and MS components as well as their associations with socioeconomic status among rural Chinese adults.

Methods

A cross-sectional study of 26,836 participants aged 20 years and older was conducted from June to December 2012 in Yuhuan City, Zhejiang Province, China, which is located on Yuhuan Island. A multivariable logistic regression model was used to identify risk factors for MS and their possible interactions.

Results

Among 26,836 subjects with an average age of 53.4 ± 14.0 years, 59% were female. The overall prevalence of MS was 20.5%, and there was a significant sex difference in the prevalence (15.1% for males vs. 24.2% for females, P < 0.001). Compared with males, females also showed a significantly higher proportion of most MS components. A significantly higher prevalence of MS was found among subjects who were elderly, had a lower income level, had a lower level of education, or were unemployed. Multiple significant interactions were observed between the prevalence of MS and sex, age or socioeconomic status (P < 0.001). The risk of MS increased significantly with age in females but not in males. Additionally, a lower income level and a lower level of education were significantly related to an increased risk only in females, and unemployed males had a higher risk of MS than unemployed females.

Conclusions

The prevalence of MS and its components was relatively high in a rural island Chinese population with rapid urbanization, and sex-specific associations between socioeconomic factors and MS were found. Targeted preventive interventions should be developed and implemented to prevent and control MS among those with low socioeconomic status, especially females.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12074-z.

Association between the metabolic syndrome and muscle weakness among Chinese older adults: results from the China Health and Retirement Longitudinal Study

BACKGROUND

Metabolic syndrome (MetS) may adversely influence muscle strength. However, the relationship remains poorly understood in China, despite its large older population and the high prevalence of MetS.

OBJECTIVES

We aimed to investigate the association between MetS and muscle weakness among older Chinese.

METHODS

We included 2,418 older adults who completed the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study (CHARLS) and had normal handgrip strength at baseline. Data were analyzed using descriptive statistics and logistic regressions.

RESULTS

Baseline MetS was associated with increased risks for incident muscle weakness (OR = 1.35, 95% CI: 1.08-1.67). Among all the MetS components, baseline central obesity component was predictive of muscle weakness. The association between MetS and declined muscle strength existed in men but not women.

CONCLUSION

There was an increased risk of muscle strength decline associated with MetS, which was more prominent in men.

Association between T2DM and the lowering of testosterone levels among Kashmiri males

OBJECTIVE

The objective of this study is to study association between testosterone and diabetes in Kashmiri males.

METHODS

A total of 300 males with Type 2 diabetes visited an outpatient and inpatient clinic at Shri Maharaja Hari Singh (SMHS) hospital, Srinagar, J&K India. The blood sugar and HbA1c, which are the markers of diabetes, and sérum testosterone levels were measured. The blood samples from both the cases and controls were collected.

RESULTS

Out of 300 subjects, 42% had a testosterone deficiency. A relationship between type 2 diabetic males and healthy males was observed, and testosterone levels were determined to be significantly lower among diabetic males (p < 0.001) when compared to healthy males. Then, we compared diabetic markers among testosterone deficient and normal testosterone level groups; the mean fasting plasma glucose (p = 0.0019) and glycated haemoglobin (HbA1c; p = 0.0449) levels were significantly higher in the testosterone deficient group than in the control group. To elucidate the relationship between the serum total testosterone level and fasting plasma glucose and HbA1c values, Pearson's correlation test was performed. Fasting plasma glucose levels (r = -0.252, p = 0.001) and HbA1c values (r = -0.697, p = 0.001) showed a significant negative correlation with serum testosterone levels among diabetic males.

CONCLUSION

This study shows that diabetes causes low testosterone levels among males, and lower testosterone levels can act as a marker for diabetes. Thus, with timely intervention, mortality and co-morbidity associated with diabetes can be prevented.

Association of Serum Testosterone and Luteinizing Hormone With Blood Pressure and Risk of Cardiovascular Disease in Middle-Aged and Elderly Men

Background

The age‐related decline in testosterone levels is thought to be of great importance for male aging and cardiovascular diseases. However, data are controversial on whether abnormal sex hormones are linked to the presence of cardiovascular diseases and it is also uncertain how blood pressure modifies the association between testosterone levels and major cardiovascular diseases.

Methods and Results

This is a multicenter, population‐based, cross‐sectional study of 6296 men conducted between 2013 and 2016. Basic information and clinical symptoms were obtained by questionnaires. Blood pressure and plasma levels of total testosterone, sex hormone–binding globulin, luteinizing hormone, and free testosterone were determined in men in a multistage random, cluster sampling in 6 provinces of China. There were 5786 Chinese men (mean [SD] age 55.0 [10.1] years) included after exclusion criteria were applied; 37.2% (2150) of them were diagnosed with hypertension. Total testosterone, free testosterone, and sex hormone–binding globulin were inversely associated with the prevalence of hypertension. Age >65 years or body mass index ≥24 negatively impacted the inverse correlation between testosterone levels and hypertension, whereas smoking and family history of hypertension strengthened the correlation. In participants with grade 2 hypertension, total testosterone was positively associated with the presence of stroke, and luteinizing hormone was also positively correlated with cardiovascular and cerebrovascular diseases.

Conclusions

Lower total testosterone could be a promising risk marker for prevalent hypertension. Both low and high levels of testosterone are associated with greater cardiovascular risk. Primary hypogonadism may be a risk marker for major cardiovascular diseases in men with severe hypertension.

Incidence and Risk Factors of Hypogonadism in Male Patients With Latent Autoimmune Diabetes and Classic Type 2 Diabetes

OBJECTIVES

This study aimed to compare the prevalence of hypogonadism between male patients with latent autoimmune diabetes (LADA) and type 2 diabetes (T2DM) and investigate the risk factors for hypogonadism in these patients.

METHODS

This cross-sectional study evaluated 367 male patients with LADA (n=73) and T2DM (n=294) who visited the endocrinology department of Shanghai Tenth People's Hospital between January 2016 and October 2019 for diabetes management. Sex hormones, lipid profiles, sex hormone-binding globulin (SHBG), glycosylated hemoglobin A1c, beta-cell function, uric acid, and osteocalcin were determined in serum samples. Hypogonadism was defined as calculated free testosterone (cFT) less than 220 pmol/L along with the presence of symptoms (positive ADAM score).

RESULTS

The rate of hypogonadism in the LADA and T2DM group were 8.2, and 21.7%, respectively (p=0.017). After adjusting possible confounders, the rate of hypogonadism in the LADA group was comparable to those of the T2DM group. Univariate logistic regressions demonstrated that age, BMI, fasting C-peptide, triglycerides, total cholesterol and uric acid were associated with hypogonadism in men with diabetes, BMI, triglycerides and estradiol were independent risk for hypogonadism in men with diabetes.

CONCLUSION

This is the first evidence to explore the rate of hypogonadism in male patients with latent autoimmune diabetes (LADA). In the population requiring admission to a large urban hospital in China, the rate of hypogonadism was comparable to those of the T2DM group after adjusting for possible confounders. BMI, triglycerides and estradiol were independently associated with the presence of HH in male diabetic patients.

Lifestyle, metabolic disorders and male hypogonadism - A one-way ticket?

Hypogonadism is more frequent among men with common metabolic diseases, notably obesity and type 2 diabetes. Indeed, endocrine disruption caused by metabolic diseases can trigger the onset of hypogonadism, although the underlying molecular mechanisms are not entirely understood. Metabolic diseases are closely related to unhealthy lifestyle choices, such as dietary habits and sedentarism. Therefore, hypogonadism is part of a pathological triad gathering unhealthy lifestyle, metabolic disease and genetic background. Additionally, hypogonadism harbors the potential to aggravate underlying metabolic disorders, further sustaining the mechanisms leading to disease. To what extent does lifestyle intervention in men suffering from these metabolic disorders can prevent, improve or reverse hypogonadism, is still controversial. Moreover, recent evidence suggests that the metabolic status of the father is related to the risk of inter and transgenerational inheritance of hypogonadism. In this review, we will address the proposed mechanisms of disease, as well as currently available interventions for hypogonadism.

Considerations for Studying Sex as a Biological Variable in Spinal Cord Injury

In response to NIH initiatives to investigate sex as a biological variable in preclinical animal studies, researchers have increased their focus on male and female differences in neurotrauma. Inclusion of both sexes when modeling neurotrauma is leading to the identification of novel areas for therapeutic and scientific exploitation. Here, we review the organizational and activational effects of sex hormones on recovery from injury and how these changes impact the long-term health of spinal cord injury (SCI) patients. When determining how sex affects SCI it remains imperative to expand outcomes beyond locomotor recovery and consider other complications plaguing the quality of life of patients with SCI. Interestingly, the SCI field predominately utilizes female rodents for basic science research which contrasts most other male-biased research fields. We discuss the unique caveats this creates to the translatability of preclinical research in the SCI field. We also review current clinical and preclinical data examining sex as biological variable in SCI. Further, we report how technical considerations such as housing, size, care management, and age, confound the interpretation of sex-specific effects in animal studies of SCI. We have uncovered novel findings regarding how age differentially affects mortality and injury-induced anemia in males and females after SCI, and further identified estrus cycle dysfunction in mice after injury. Emerging concepts underlying sexually dimorphic responses to therapy are also discussed. Through a combination of literature review and primary research observations we present a practical guide for considering and incorporating sex as biological variable in preclinical neurotrauma studies.

Clinical relevance of different handgrip strength indexes and metabolic syndrome in Chinese community-dwelling elderly individuals

PURPOSE

Currently there is no consensus on the correlation between metabolic syndrome (MetS) and muscle strength. The objective of this study was to examine the associations between MetS and its components and different handgrip strength (HS) indexes among Chinese community-dwelling elderly individuals. In addition, we hoped to find an optimal cutoff point for the index most relevant to MetS.

METHODS

Data were obtained from 909 participants aged ≥ 60 years (385 men, average age, 68.0 ± 5.9 y). We used the International Diabetes Federation metabolic syndrome guidelines to define MetS. General data of all participants were collected through questionnaires and anthropometric data were measured. At the same time, blood samples were collected.

RESULTS

The prevalence of MetS was 26.8 % in men and 46.9 % in women. In all HS indexes, HS/body fat mass was most strongly correlated with MetS, and the areas under the receiver-operating characteristic curve were 0.723 (95 % confidence interval [CI] = 0.669-0.776) in men and 0.619 (95 % CI = 0.571-0.667) in women, and the optimal cutoffs were 1.92 in men and 1.25 in women. The adjusted odds ratios (ORs) of MetS for low HS/body fat mass were 5.38 (95 % CI = 3.03-9.56, p < 0.001) in men and 2.39 (95 % CI = 1.56-3.64, p < 0.001) in women.

CONCLUSIONS

HS/body fat mass appears to be the index best associated with MetS and its components, and in men it is more relevant than in women.

Clinical and metabolic implications of obesity in prostate cancer: is testosterone a missing link?

Objectives: To assess sex hormones in men with obesity and prostate cancer (PCa) and to study association between androgens and the pathogenesis biology of PCa in vitro. Subjects and methods: One hundred and eighty-one men older than 45 years selected from of a population attending to Urology departments screening for PCa, (78 participants without PCa and 103 patients with PCa). All participants were assessed for body mass index (BMI), age, Gleason score, and PSA. Endocrine profile was determined for LH, total testosterone (TT), 17β-estradiol (E2), prolactin and leptin. Biochemical profile (HbA1c, triacylglycerols and lipoproteins) was also determined. In vitro experiments were also performed, involving the study of 5α-dihydrotestosterone (DHT) and E2 in the presence of adipocyte-conditioned medium (aCM). Results: All variables were continuous and described a Gaussian distribution unless mentioned. To determine the relation of aggressiveness, variable were transformed into categories. Thus, PCa aggressiveness is associated with the increase of age and BMI (p < .0001) but with is decreased with TT and E2 (p < .05). Moreover, adipocyte-secreted molecules increase aggressiveness of PCa cells in vitro. Lastly, DTH but not E2 enables invasiveness in vitro. Conclusions: It was observed a coexistence of hormone axis profile alteration with sex hormones and BMI in PCa patients, in accordance with the new perspective of PCa pathogenesis.

Human Adipose-derived Pericytes Display Steroidogenic Lineage Potential in Vitro and Influence Leydig Cell Regeneration in Vivo in Rats

Exogenous androgen replacement is used to treat symptoms associated with low testosterone in males. However, adverse cardiovascular risk and negative fertility impacts impel development of alternative approaches to restore/maintain Leydig cell (LC) androgen production. Stem Leydig cell (SLC) transplantation shows promise in this regard however, practicality of SLC isolation/transplantation impede clinical translation. Multipotent human adipose-derived perivascular stem cells (hAd-PSCs) represent an attractive extragonadal stem cell source for regenerative therapies in the testis but their therapeutic potential in this context is unexplored. We asked whether hAd-PSCs could be converted into Leydig-like cells and determined their capacity to promote regeneration in LC-ablated rat testes. Exposure of hAd-PSCs to differentiation-inducing factors in vitro upregulated steroidogenic genes but did not fully induce LC differentiation. In vivo, no difference in LC-regeneration was noted between Sham and hAd-PSC-transplanted rats. Interestingly, Cyp17a1 expression increased in hAd-PSC-transplanted testes compared to intact vehicle controls and the luteinising hormone/testosterone ratio returned to Vehicle control levels which was not the case in EDS + Sham animals. Notably, hAd-PSCs were undetectable one-month after transplantation suggesting this effect is likely mediated via paracrine mechanisms during the initial stages of regeneration; either directly by interacting with regenerating LCs, or through indirect interactions with trophic macrophages.

The Association between Serum Testosterone and Risk Factors for Atherosclerosis

Objective

To study the associations between serum testosterone and risk factors for atherosclerosis in 119 men from general population.

Methods

Systolic pressure, body mass index (BMI), testosterone, fasting glucose, glucose tolerance test, apolipoprotein A-1 (ApoA-1), apolipoprotein B (ApoB), and ApoB/ApoA-1 ratio were assessed. Subjects classified into hypogonadal (testosterone ≤ 12 nmol/l), and eugonadal men (testosterone > 12 nmol/l).

Results

BMI (28 vs. 26 kg/ m², p = 0.01), systolic pressure (129 vs. 123 mmHg, p = 0.03), fasting glucose (5.9 vs. 5.5 mmol/l, p = 0.03), ApoB (1.1 vs. 1.0 g/l, p = 0.03), and ApoB/ApoA-1 ratio (0.8 vs. 0.7, p = 0.03) were higher in hypogonadal compared to eugonadal men, respectively. In adjusted multivariate regression analysis model, testosterone showed negative associations with BMI (β = -1.832, p = 0.030, 95% CI = -3.485--0.180), fasting glucose (β = -0.394, p = 0.011, 95% CI = -0.696--0.091), glucose tolerance test (β = -0.957, p = 0.045, 95% CI = -1.892--0.022), ApoB (β = -0.157, p = 0.017, 95% CI = -0.286--0.029), and ApoB/ApoA-1 ratio (β = -0.118, p = 0.046, 95% CI = -0.234--0.002).

Conclusions

These results suggest an inverse association between testosterone levels and risk factors for atherosclerosis.

Clinical and Genetic Risk Factors for Adverse Metabolic Outcomes in North American Testicular Cancer Survivors

Background: Testicular cancer survivors (TCS) are at significantly increased risk for cardiovascular disease (CVD), with metabolic syndrome (MetS) an established risk factor. No study has addressed clinical and genetic MetS risk factors in North American TCS. Patients and Methods: TCS were aged <55 years at diagnosis and received first-line chemotherapy. Patients underwent physical examination, and had lipid panels, testosterone, and soluble cell adhesion molecule-1 (sICAM-1) evaluated. A single nucleotide polymorphism in rs523349 (5-α-reductase gene, SRD5A2), recently implicated in MetS risk, was genotyped. Using standard criteria, MetS was defined as ≥3 of the following: hypertension, abdominal obesity, hypertriglyceridemia, decreased high-density lipoprotein (HDL) cholesterol level, and diabetes. Matched controls were derived from the National Health and Nutrition Examination Survey. Results: We evaluated 486 TCS (median age, 38.1 years). TCS had a higher prevalence of hypertension versus controls (43.2% vs 30.7%; P<.001) but were less likely to have decreased HDL levels (23.7% vs 34.8%; P<.001) or abdominal obesity (28.2% vs 40.1%; P<.001). Overall MetS frequency was similar in TCS and controls (21.0% vs 22.4%; P=.59), did not differ by treatment (P=.20), and was not related to rs523349 (P=.61). For other CVD risk factors, TCS were significantly more likely to have elevated low-density lipoprotein (LDL) cholesterol levels (17.7% vs 9.3%; P<.001), total cholesterol levels (26.3% vs 11.1%; P<.001), and body mass index ≥25 kg/m² (75.1% vs 69.1%; P=.04). On multivariate analysis, age at evaluation (P<.001), testosterone level ≤3.0 ng/mL (odds ratio [OR], 2.06; P=.005), and elevated sICAM-1 level (OR_{highest vs lowest quartile}, 3.58; P=.001) were significantly associated with MetS. Conclusions and Recommendations: Metabolic abnormalities in TCS are characterized by hypertension and increased LDL and total cholesterol levels but lower rates of decreased HDL levels and abdominal obesity, signifying possible shifts in fat distribution and fat metabolism. These changes are accompanied by hypogonadism and inflammation. TCS have a high prevalence of CVD risk factors that may not be entirely captured by standard MetS criteria. Cancer treatment-associated MetS requires further characterization.

Aging and the Male Reproductive System

This narrative review presents an overview of current knowledge on fertility and reproductive hormone changes in aging men, the factors driving and modulating these changes, their clinical consequences, and the benefits and risks of testosterone (T) therapy. Aging is accompanied by moderate decline of gamete quality and fertility. Population mean levels show a mild total T decline, an SHBG increase, a steeper free T decline, and a moderate LH increase with important contribution of comorbidities (e.g., obesity) to these changes. Sexual symptoms and lower hematocrit are associated with low T and are partly responsive to T therapy. The relationship of serum T with body composition and metabolic health is bidirectional; limited beneficial effects of T therapy on body composition have only marginal effects on metabolic health and physical function. Skeletal changes are associated primarily with estradiol and SHBG. Cognitive decline is not consistently linked to low T and is not improved by T therapy. Although limited evidence links moderate androgen decline with depressive symptoms, T therapy has small beneficial effects on mood, depressive symptoms, and vitality in elderly patients with low T. Suboptimal T (and/or DHT) has been associated with increased risk of stroke, but not of ischemic heart disease, whereas an association with mortality probably reflects that low T is a marker of poor health. Globally, neither severity of clinical consequences attributable to low T nor the nature and magnitude of beneficial treatment effects justify the concept of some broadly applied "T replacement therapy" in older men with low T. Moreover, long-term safety of T therapy is not established.

Androgen receptor signalling in the male adrenal facilitates X-zone regression, cell turnover and protects against adrenal degeneration during ageing

Androgens are known to be an essential regulator of male health. Androgen receptor (AR) is widely expressed throughout the adrenal cortex, yet the wider role for androgen signalling in the adrenal remains underexplored. To investigate AR-dependent and AR-independent androgen signalling in the adrenal, we used a novel mouse model with a specific ablation of androgen receptor in the adrenal cortex with or without reduction of circulating androgen levels by castration. Our results describe AR expression in the human and mouse adrenal and highlight that the mouse is a viable model to investigate androgen signalling in the adrenal cortex. We show androgen signalling via AR is required for X-zone regression during puberty. Furthermore, cortex measurements define differences in X-zone morphology depending on whether circulating androgens or AR have been removed. We show androgens promote both cortical cell differentiation and apoptosis but are dispensable for the formation of the definitive cortex. Additionally, investigation of aged mice with AR ablation reveals severe cortex disruption, spindle cell hyperplasia and X-zone expansion. The data described herein demonstrates AR-signalling is required to facilitate X-zone regression, cell clearance and to protect against adrenal degeneration during ageing.

Relationship of transcriptional markers to Leydig cell number in the mouse testis

Objectives

The current study aims to identify markers that would reflect the number of Leydig cells present in the testis, to help determine whether labour-intensive methods such as stereology are necessary. We used our well-characterised Sertoli cell ablation model in which we have empirically established the size of the Leydig cell population, to try to identify transcriptional biomarkers indicative of population size.

Results

Following characterisation of the Leydig cell population after Sertoli cell ablation in neonatal life or adulthood, we identified Hsd3b1 transcript levels as a potential indicator of Leydig cell number with utility for informing decision-making on whether to engage in time-consuming stereological cell counting analysis.

Associations of Metabolic Syndrome with Total Testosterone and Homocysteine Levels in Male Korean Workers

BACKGROUND

Low testosterone is associated with metabolic syndrome (MetS), and homocysteine (Hcy) is elevated in individuals with MetS. We investigated the relationships of total testosterone (TT) and serum Hcy levels with MetS in male Korean workers.

METHODS

We conducted a cross-sectional study including 8,606 male workers, aged 20 to 58 years, who underwent a physical examination in 2015. MetS was diagnosed based on the criteria of the 2009 harmonized definition, while the Korean standard for waist circumference (WC) was used. Participants' biochemical parameters, including TT and serum Hcy, were measured, and participants were divided into quartiles. Multiple logistic regression models were used to estimate the association of MetS and its individual components depending on TT and serum Hcy quartiles.

RESULTS

The prevalence of MetS in the study population was 16%. TT was lower in participants with MetS than in those without MetS (P<0.001). By contrast, Hcy level was similar between groups (P=0.694). In multiple logistic regression analysis, the odds ratio for the lowest TT quartile was 1.29 (95% confidence interval, 1.06 to 1.57) after adjusting for potential confounders. Participants with lower TT were more likely to have high WC, hypertriglyceridemia, and low high density lipoprotein levels. Serum Hcy levels were not significantly associated with MetS. Of the five components of MetS, only WC was significantly associated with serum Hcy.

CONCLUSION

In male Korean workers, TT may be an independent predictor of MetS, and serum Hcy levels could be a marker of abdominal obesity. However, future prospective studies are needed.

Adverse Health Outcomes in Relationship to Hypogonadism After Chemotherapy: A Multicenter Study of Testicular Cancer Survivors

BACKGROUND

This study examined the prevalence of hypogonadism, its clinical and genetic risk factors, and its relationship to adverse health outcomes (AHOs) in North American testicular cancer survivors (TCS) after modern platinum-based chemotherapy.

PATIENTS AND METHODS

Eligible TCS were <55 years of age at diagnosis and treated with first-line platinum-based chemotherapy. Participants underwent physical examinations and completed questionnaires regarding 15 AHOs and health behaviors. Hypogonadism was defined as serum testosterone levels ≤3.0 ng/mL or use of testosterone replacement therapy. We investigated the role of 2 single nucleotide polymorphisms (rs6258 and rs12150660) in the sex hormone-binding globulin (SHBG) locus implicated in increased hypogonadism risk in the general population.

RESULTS

Of 491 TCS (median age at assessment, 38.2 years; range, 18.7-68.4 years), 38.5% had hypogonadism. Multivariable binary logistic regression analysis identified hypogonadism risk factors, including age at clinical evaluation (odds ratio [OR], 1.42 per 10-year increase; P= .006) and body mass index of 25 to <30 kg/m2 (OR, 2.08; P= .011) or ≥30 kg/m2 (OR, 2.36; P= .005) compared with <25 kg/m2. TCS with ≥2 risk alleles for the SHBG SNPs had a marginally significant increased hypogonadism risk (OR, 1.45; P= .09). Vigorous-intensity physical activity appeared protective (OR, 0.66; P= .07). Type of cisplatin-based chemotherapy regimen and socioeconomic factors did not correlate with hypogonadism. Compared with TCS without hypogonadism, those with hypogonadism were more likely to report ≥2 AHOs (65% vs 51%; P= .003), to take medications for hypercholesterolemia (20.1% vs 6.0%; P<.001) or hypertension (18.5% vs 10.6%; P= .013), and to report erectile dysfunction (19.6% vs 11.9%; P= .018) or peripheral neuropathy (30.7% vs 22.5%; P= .041). A marginally significant trend for increased use of prescription medications for either diabetes (5.8% vs 2.6%; P= .07) or anxiety/depression (14.8% vs 9.3%; P= .06) was observed.

CONCLUSIONS

At a relatively young median age, more than one-third of TCS have hypogonadism, which is significantly associated with increased cardiovascular disease risk factors, and erectile dysfunction. Providers should screen TCS for hypogonadism and treat symptomatic patients.

The potential role of testosterone in hypertension and target organ damage in hypertensive postmenopausal women

Objective: The aim of this study was to confirm the potential role of testosterone in hypertension and target organ damage (TOD) in hypertensive postmenopausal women.

Methods: A matched group study was conducted. One hundred sixty-one hypertensive postmenopausal women between 45 and 65 years of age were enrolled as group 1. Another 161 age-matched hypertensive men were enrolled as group 2. Ambulatory blood pressure monitoring, echocardiographic imaging, vascular function, sex hormones and clinical characteristics were evaluated. Quantitative data were analyzed using independent Student’s t-test and multiple regression analysis.

Results: The mean and load level of blood pressure were lower in women than in men (P<0.05), except for the mean level and load of the nocturnal systolic blood pressure (SBP) (123.77±15.72 mmHg vs 126.35±15.64 mmHg, and 50.43±30.31% vs 55.35±28.51%, P>0.05). However, the carotid-femoral pulse wave velocity (cf-PWV) in women was higher than that in men (9.68±2.23 m/s vs 8.03±2.82 m/s, P<0.05). The ratio of the early diastolic mitral peak flow velocity to early diastolic mitral annular velocity (E/Em) was obviously impaired (13.06±3.53 vs 12.05±3.68, P<0.05) in women. Furthermore, in women, a positive correlation was found between testosterone and cf-PWV (γ=0.157, P=0.046), and Cf-PWV was positively related to the mean level of nighttime SBP (γ=0.210, P=0.008). Moreover, nocturnal SBP was a risk factor for E/Em (γ=0.156, P=0.048, P<0.05).

Conclusion: Testosterone may play a role in the correlation between hypertension and TOD in hypertensive postmenopausal women.

Clinical Trial number: This research study was registered under the ClinicalTrials.gov PRS Website (NCT03451747).

Metabolic Disorders and Male Hypogonadotropic Hypogonadism

Several studies highlight that testosterone deficiency is associated with, and predicts, an increased risk of developing metabolic disorders, and, on the other hand, is highly prevalent in obesity, metabolic syndrome and type-2 diabetes mellitus. Models of gonadotropin releasing hormone deficiency, and androgen deprivation therapy in patients with prostate cancer, suggest that hypogonadotropic hypogonadism might contribute to the onset or worsening of metabolic conditions, by increasing visceral adiposity and insulin resistance. Nevertheless, in functional hypogonadism, as well as in late onset hypogonadism, the relationship between hypogonadotropic hypogonadism and metabolic disorders is bidirectional, and a vicious circle between the two components has been documented. The mechanisms underlying the crosstalk between testosterone deficiency and metabolic disorders include increased visceral adipose tissue and insulin resistance, leading to development of metabolic disorders, which in turn contribute to a further reduction of testosterone levels. The decrease in testosterone levels might be determined by insulin resistance-mediated and, possibly, pro-inflammatory cytokine-mediated decrease of sex hormone binding globulin, resulting in a temporary increased free testosterone available for aromatization to estradiol in visceral adipose tissue, followed by a subsequent decrease in free testosterone levels, due to the excess of visceral adipose tissue and aromatization; by a direct inhibitory effect of increased leptin levels on Leydig cells; and by a reduced gonadotropin secretion induced by estradiol, inflammatory mediators, leptin resistance, and insulin resistance, with the ultimate determination of a substantial hypogonadotropic hypogonadism. The majority of studies focusing on the effects of testosterone replacement therapy on metabolic profile reported a beneficial effect of testosterone on body weight, waist circumference, body mass index, body composition, cholesterol levels, and glycemic control. Consistently, several interventional studies demonstrated that correction of metabolic disorders, in particular with compounds displaying a greater impact on body weight and insulin resistance, improved testosterone levels. The aim of the current review is to provide a comprehensive overview on the relationship between hypogonadotropic hypogonadism and metabolism, by clarifying the independent role of testosterone deficiency in the pathogenesis of metabolic disorders, and by describing the relative role of testosterone deficiency and metabolic impairment, in the context of the bidirectional relationship between hypogonadism and metabolic diseases documented in functional hypogonadotropic hypogonadism. These aspects will be assessed by describing metabolic profile in men with hypogonadotropic hypogonadism, and androgenic status in men with metabolic disorders; afterwards, the reciprocal effects of testosterone replacement therapy and corrective interventions on metabolic derangements will be reported.

Contributions of sex to cerebrovascular function and pathology

Sex differences exist in how cerebral blood vessels function under both physiological and pathological conditions, contributing to observed sex differences in risk and outcomes of cerebrovascular diseases (CBVDs), such as vascular contributions to cognitive impairment and dementia (VCID) and stroke. Throughout most of the lifespan, women are protected from CBVDs; however, risk increases following menopause, suggesting sex hormones may play a significant role in this protection. The cerebrovasculature is a target for sex hormones, including estrogens, progestins, and androgens, where they can influence numerous vascular functions and pathologies. While there is a plethora of information on estrogen, the effects of progestins and androgens on the cerebrovasculature are less well-defined. Estrogen decreases cerebral tone and increases cerebral blood flow, while androgens increase tone. Both estrogens and androgens enhance angiogenesis/cerebrovascular remodeling. While both estrogens and androgens attenuate cerebrovascular inflammation, pro-inflammatory effects of androgens under physiological conditions have also been demonstrated. Sex hormones exert additional neuroprotective effects by attenuating oxidative stress and maintaining integrity and function of the blood brain barrier. Most animal studies utilize young, healthy, gonadectomized animals, which do not mimic the clinical conditions of aging individuals likely to get CBVDs. This is also concerning, as sex hormones appear to mediate cerebrovascular function differently based on age and disease state (e.g. metabolic syndrome). Through this review, we hope to inspire others to consider sex as a key biological variable in cerebrovascular research, as greater understanding of sex differences in cerebrovascular function will assist in developing personalized approaches to prevent and treat CBVDs.

Sex differences in risk factors for vascular contributions to cognitive impairment & dementia

Vascular contributions to cognitive impairment and dementia (VCID) is the second most common cause of dementia. While males overall appear to be at a slightly higher risk for VCID throughout most of the lifespan (up to age 85), some risk factors for VCID more adversely affect women. These include female-specific risk factors associated with pregnancy related disorders (e.g. preeclampsia), menopause, and poorly timed hormone replacement. Further, presence of certain co-morbid risk factors, such as diabetes, obesity and hypertension, also may more adversely affect women than men. In contrast, some risk factors more greatly affect men, such as hyperlipidemia, myocardial infarction, and heart disease. Further, stroke, one of the leading risk factors for VCID, has a higher incidence in men than in women throughout much of the lifespan, though this trend is reversed at advanced ages. This review will highlight the need to take biological sex and common co-morbidities for VCID into account in both preclinical and clinical research. Given that there are currently no treatments available for VCID, it is critical that we understand how to mitigate risk factors for this devastating disease in both sexes.

Stress Hyperglycemia in Patients with Tuberculosis Disease: Epidemiology and Clinical Implications

PURPOSE OF REVIEW

The intersection of tuberculosis (TB) disease and type 2 diabetes mellitus is severely hindering global efforts to reduce TB burdens. Diabetes increases the risk of developing TB disease and negatively impacts TB treatment outcomes including culture conversion time, mortality risk, and TB relapse. Recent evidence also indicates plausible mechanisms by which TB disease may influence the pathogenesis and incidence of diabetes. We review the epidemiology of stress hyperglycemia in patients with TB and the pathophysiologic responses to TB disease that are related to established mechanisms of stress hyperglycemia. We also consider clinical implications of stress hyperglycemia on TB treatment, and the role of TB disease on risk of diabetes post-TB.

RECENT FINDINGS

Among patients with TB disease, the development of stress hyperglycemia may influence the clinical manifestation and treatment response of some patients and can complicate diabetes diagnosis. Research is needed to elucidate the relationship between TB disease and stress hyperglycemia and determine the extent to which stress hyperglycemia impacts TB treatment response. Currently, there is insufficient data to support clinical recommendations for glucose control among patients with TB disease, representing a major barrier for efforts to improve treatment outcomes for patients with TB and diabetes.

A young testicular microenvironment protects Leydig cells against age-related dysfunction in a mouse model of premature aging

Testicular Leydig cells (LCs) are the primary source of circulating androgen in men. As men age, circulating androgen levels decline. However, whether reduced LC steroidogenesis results from specific effects of aging within LCs or reflects degenerative alterations to the wider supporting microenvironment is unclear; inability to separate intrinsic LC aging from that of the testicular microenvironment in vivo has made this question difficult to address. To resolve this, we generated novel mouse models of premature aging, driven by CDGSH iron sulfur domain 2 (Cisd2) deletion, to separate the effects of cell intrinsic aging from extrinsic effects of aging on LC function. At 6 mo of age, constitutive Cisd2-deficient mice display signs of premature aging, including testicular atrophy, reduced LC and Sertoli cell (SC) number, decreased circulating testosterone, increased luteinizing hormone/testosterone ratio, and decreased expression of steroidogenic mRNAs, appropriately modeling primary testicular dysfunction observed in aging men. However, mice with Cisd2 deletion (and thus premature aging) restricted to either LCs or SCs were protected against testicular degeneration, demonstrating that age-related LCs dysfunction cannot be explained by intrinsic aging within either the LC or SC lineages alone. We conclude that age-related LC dysfunction is largely driven by aging of the supporting testicular microenvironment.—Curley, M., Milne, L., Smith, S., Jørgensen, A., Frederiksen, H., Hadoke, P., Potter, P., Smith, L. B. A Young testicular microenvironment protects Leydig cells against age-related dysfunction in a mouse model of premature aging.

Metabolism of sex steroids is influenced by acquired adiposity-A study of young adult male monozygotic twin pairs

Obesity and ageing are associated with lower serum testosterone levels in men. How fat distribution or adipose tissue metabolism, independent of genetic factors and age, are related to sex steroid metabolism is less clear. We studied the associations between adiposity and serum sex hormone concentrations, and mRNA expression of genes regulating sex hormone metabolism in adipose tissue in young adult male monozygotic (MZ) twin pairs. The subjects [n=18 pairs; mean age, 32 years; individual body mass indexes (BMIs) 22-36kg/m²] included 9 male MZ twin pairs discordant for BMI [intra-pair difference (Δ) in BMI ≥3kg/m²]. Sex steroid concentrations were determined by liquid chromatography-tandem mass spectrometry, body composition by dual-energy X-ray absorptiometry and magnetic resonance imaging, and mRNA expressions from subcutaneous adipose tissue by Affymetrix. In BMI-discordant pairs (mean ΔBMI=5.9kg/m²), serum dihydrotestosterone (DHT) was lower [mean 1.9 (SD 0.7) vs. 2.4 (1.0) nmol/l, P=0.040] and mRNA expressions of DHT-inactivating AKR1C2 (P=0.021) and cortisol-producing HSD11B1 (P=0.008) higher in the heavier compared to the leaner co-twins. Serum free 17β-estradiol (E2) was higher [2.3 (0.5) vs. 1.9 (0.5) pmol/l, P=0.028], and in all twin pairs, serum E2 and estrone concentrations were higher in the heavier than in the leaner co-twins [107 (28) vs. 90 (22) pmol/l, P=0.006; and 123 (43) vs. 105 (27) pmol/l, P=0.025]. Within all twin pairs, i.e. independent of genetic effects and age, 1) the amount of subcutaneous fat inversely correlated with serum total and free testosterone, DHT, and sex hormone-binding globulin (SHBG) concentrations (P<0.01 for all), 2) intra-abdominal fat with total testosterone and SHBG (P<0.05), and 3) liver fat with SHBG (P=0.006). Also, 4) general and intra-abdominal adiposity correlated positively with mRNA expressions of AKR1C2, HSD11B1, and aromatase in adipose tissue (P<0.05). In conclusion, acquired adiposity was associated with decreased serum DHT and increased estrogen concentrations, independent of genetic factors and age. The reduction of DHT could be linked to its increased degradation (by AKR1C2 and HSD11B1) and increased estrogen levels to increased adiposity-related expression of aromatase in adipose tissue.

Gender difference in the association between lower muscle mass and metabolic syndrome independent of insulin resistance in a middle-aged and elderly Taiwanese population

BACKGROUND

Loss of muscle mass was reported to be associated with metabolic syndrome (MetS), but little is known about the gender difference. Thus, the aim of this study was to evaluate the relationship between lower muscle mass and MetS and determine whether there was any gender difference or not.

METHODS

A total of 394 middle-aged and elderly Taiwanese adults (138 males and 256 females) were enrolled and completed our health survey. They were stratified into three groups according to appendicular skeletal muscle mass divided by weight. Participants distributed into the lower tertile were defined as people having lower muscle mass. MetS was defined using the Adult Treatment Panel III Asian diagnostic criteria. Multivariate logistic regression analysis was performed to assess the association between muscle and MetS.

RESULTS

We found an inverse association between MetS and muscle mass in both males and females. Participants with lower muscle mass had a higher risk of MetS in univariate analysis. The same results were observed when adjusted for age and when also adjusted for living condition factors. However, after additional adjustment for potential confounders and HOMA-IR, we only found it to be statistically significant in the female group (OR in male=3.60; 95% CI=0.62-20.83, p=0.153; OR in female=3.03; 95% CI=1.16-7.94, p=0.024).

CONCLUSIONS

We examined the relationship between lower muscle mass and metabolic syndrome in a middle-aged and elderly Taiwanese population. We found that lower muscle mass was associated with the risk of metabolic syndrome in the aged, particularly in females.

Ethnic differences in male reproductive hormones and relationships with adiposity and insulin resistance in older men

OBJECTIVES

To assess ethnic differences in male reproductive hormone levels and to determine whether any differences are explained by adiposity, insulin resistance (IR) or comorbidities in older men.

DESIGN

Multi-ethnic cross-sectional observational study.

PARTICIPANTS

Community dwelling middle-aged and elderly men residing in the UK aged 40-84 years of South Asian (SA; n = 180), White European (WE; n = 328) or African Caribbean (AC; n = 166) origin.

OBSERVATIONS

Measured testosterone (T), calculated free T (cFT), sex hormone-binding globulin and LH in SA, WE and AC men along with an assessment of body composition, IR, lifestyle factors and medical conditions.

RESULTS

Age-adjusted mean T and cFT levels were lower in SA men when compared to WE and AC men (mean (SEM) T: SA: 14·0 ± 0·4; WE: 17·1 ± 0·3; AC: 17·2 ± 0·5 nmol/l, P < 0·001; cFT: SA: 283 ± 7; WE: 313 ± 5; AC: 314 ± 8 pmol/l, P < 0·006). Compared to WE and AC men, SA men had higher levels of body fat, IR, comorbidities and diabetes. After adjusting for body fat, IR and other confounders, T levels in SA men remained lower than in WE men (P = 0·04) but ethnic differences in cFT became nonsignificant. LH levels were higher in SA than WE men in age-adjusted and fully adjusted models.

CONCLUSIONS

T and cFT are lower in SA men than in WE and AC men. Whether ethnic-specific reference ranges for T and cFT might be appropriate in clinical practice requires further investigation. Ethnic differences in cFT, but not T, appear to be, more readily, explained by ethnic differences in adiposity, thus providing insights into potential pathophysiological mechanisms.

Racial/Ethnic Differences in the Associations of Overall and Central Body Fatness with Circulating Hormones and Metabolic Factors in US Men

BACKGROUND

Racial/ethnic disparities in the associations of body fatness with hormones and metabolic factors remain poorly understood. Therefore, we evaluated whether the associations of overall and central body fatness with circulating sex steroid hormones and metabolic factors differ by race/ethnicity.

METHODS

Data from 1,243 non-Hispanic white (NHW), non-Hispanic black (NHB) and Mexican-American (MA) adult men in the third national health and nutrition examination survey (NHANES III) were analyzed. Waist circumference (central body fatness) was measured during the physical examination. Percent body fat (overall body fatness) was calculated from bioelectrical impedance. Associations were estimated by using weighted linear regression models to adjust the two measures of body fatness for each other.

RESULTS

Waist circumference, but not percent body fat was inversely associated with total testosterone and SHBG in all three racial/ethnic groups after their mutual adjustment (all P < 0.0001). Percent body fat (P = 0.02), but not waist circumference was positively associated with total estradiol in NHB men; no association was present in NHW and MA men (P-interaction = 0.04). Waist circumference, but not body fat was strongly positively associated with fasting insulin (all P < 0.0001) and inversely associated with HDL cholesterol (all P ≤ 0.003) in all three racial/ethnic groups. Both percent body fat and waist circumference were positively associated with leptin (all P < 0.0001) in all three racial/ethnic groups.

CONCLUSIONS

There was no strong evidence in the associations of sex hormones and metabolic factors with body fatness in different racial/ethnic groups. These findings should be further explored in prospective studies to determine their relevance in racial/ethnic disparities of chronic diseases.

Effects of taking tadalafil 5 mg once daily on erectile function and total testosterone levels in patients with metabolic syndrome

We aimed to evaluate the efficacy of tadalafil 5 mg once-daily treatment on testosterone levels in patients with erectile dysfunction (ED) accompanied by the metabolic syndrome. A total of 40 men with metabolic syndrome were evaluated for ED in this study. All the patients received 5 mg tadalafil once a day for 3 months. Erectile function was assessed using the five-item version of the International Index of Erectile Function (IIEF) questionnaire. Serum testosterone, follicle-stimulating hormone and luteinising hormone levels were also evaluated, and blood samples were taken between 08.00 and 10.00 in the fasting state. All participants have three or more criteria of metabolic syndrome. At the end of 3 months, mean testosterone values and IIEF scores showed an improvement from baseline values (from 3.6 ± 0.5 to 5.2 ± 0.3, from 11.3 ± 1.9 to 19 ± 0.8 respectively). After the treatment, serum LH levels were decreased (from 5.6 ± 0.6 to 4.6 ± 0.5). There was significantly difference in terms of baseline testosterone and luteinising hormone values and IIEF scores (p < .05). Based on our findings, we recommend tadalafil 5 mg once daily in those men with erectile dysfunction especially low testosterone levels accompanied by metabolic syndrome.

Inverse association of total testosterone with central haemodynamics and left ventricular mass in hypertensive men

BACKGROUND

There is evidence for inverse association between endogenous testosterone and blood pressure. Furthermore, low plasma testosterone is associated with increased risk of major cardiovascular events in middle-aged hypertensive men. Central (aortic) blood pressures determine left ventricular hypertrophy and predict cardiovascular mortality. The aim of the present study was to assess the relationship of total testosterone (TT) with central haemodynamics and left ventricular mass in hypertensive men.

METHODS

We investigated 134 non-diabetic, middle-aged, hypertensive men and 60 age-matched normotensive males. All participants were subject to measurement of aortic systolic (aoSBP) and pulse pressure (aoPP) by pulse wave analysis using the SphygmoCor device. Wave reflections were assessed by the measurement of heart rate corrected augmentation index (AIx75). Echocardiography was performed in all individuals and left ventricular mass (LVM) was calculated using the Devereux's formula. Plasma TT was measured by enzyme immunoassay.

RESULTS

In hypertensive men, univariate analysis showed an inverse, significant correlation between TT and aoSBP (r = -20, p = 0.02), aoPP (r = -0.21, p = 0.01), AIx75 (r = -0.22, p = 0.01) and LVM (r = -0.19, p = 0.008). Multivariate regression analysis demonstrated an independent inverse association of TT with aoPP (b = -0.21, p = 0.02), AIx75 (b = -0.19, p = 0.03) and LVM (b = -0.28, p = 0.005) after adjustment for age, BMI, smoking, total cholesterol, triglycerides, fasting glucose, mean arterial pressure, antihypertensive treatment and statin use. Independent associations were retained even after inclusion of normotensive subjects in the analysis.

CONCLUSIONS

In hypertensive men, TT is independently and inversely associated with central pulse pressure, wave reflections and left ventricular mass. Considering the adverse prognostic role of central blood pressures and LV hypertrophy on cardiovascular outcomes in hypertensive patients, the present findings might explain part of the increased cardiovascular risk associated with low testosterone. Whether measurement of central haemodynamics may improve risk stratification in hypertensive men with low testosterone warrants further investigation.

Total testosterone levels are correlated to metabolic syndrome components

INTRODUCTION

Metabolic syndrome (MetS) is a constellation of interrelated risk factors of metabolic origin. Some studies suggest a possible link between low total testosterone (TT) levels and the presence of MetS.

AIM

To analyze the strength and independence of associations between TT and MetS components in non-diabetic men.

METHODS

In this cross-sectional study, 143 non-diabetic men older than 40 were analyzed.

MAIN OUTCOMES MEASURE

Blood samples were collected to evaluate metabolic profile and TT levels. MetS was defined as the presence of three or more of the following characteristics: fasting blood glucose levels ≥ 100 mg/dL, triglyceride ≥ 150 mg/dL, HDL-c < 40 mg/dL, hypertension or blood pressure ≥ 130/85 mmHg, and waist girth > 102 cm.

RESULTS

Mean age of the study population was 61.5 ± 8.61 years old. MetS was present in 47.9% of the individuals. Thirty-four men had low TT and MetS was observed in 23 (70%) against 50 (46%) in those with normal TT (≥ 300 ng/dL) (OR 4.94, p < 0.01), adjusted to confounder's factors. In multiple linear regression analysis, only waist circumference (Beta: -0.395; p = 0.03) and HDL-c (Beta: 0.19; p = 0.04) remained significantly correlated with TT levels.

CONCLUSIONS

Low TT levels were associated with MetS diagnosis. Abdominal obesity was the MetS component independently correlated to low TT levels.

Metabolic Syndrome: Does it Differ Between Women and Men?

Cardiovascular disease represents a massive healthcare burden worldwide. Gender differences in the pathophysiology, presentation and prognosis of cardiovascular disease have been described in the literature. Metabolic syndrome, characterized by a cluster of metabolic abnormalities is associated with increased risk for type 2 diabetes mellitus and atherosclerotic cardiovascular disease. With the global obesity epidemic, the prevalence of metabolic syndrome is rising rapidly in the developed as well as developing world. However, there is considerable variation in the prevalence based on geography, age, sex and, definition used for diagnosis. Data on gender related differences in metabolic syndrome is relatively scarce. Here, we aim to review the gender differences in epidemiology and pathophysiology of metabolic syndrome as well as its individual components. Knowledge of gender differences in metabolic syndrome can help design gender specific preventative and therapeutic strategies that will have a positive impact on overall population health.

Relation of urinary stone disease with androgenetic alopecia and serum testosterone levels

We aimed to investigate the relationship among urinary stone disease, androgenetic alopecia (AGA), and serum testosterone (T) levels. Between January 2008 and November 2015, we retrospectively investigated the biochemical parameters and anthropometric characteristics (height and weight) of 200 patients who had urinary tract stones. For the control group, we selected at random 168 participants who had no history of urolithiasis. Demographic data, such as participants' age, body mass index (BMI), hypertension (HT), diabetes mellitus (DM), baldness pattern, and serum T level were recorded. All participants were male, over 18 and under 60 years of age. We determined that risk of urolithiasis increased 1.3-fold in patients with vertex pattern alopecia and 2.1-fold in patients with total alopecia compared with those with no hair loss. In the severe balding Groups (Group III and Group IV), presence of testosterone deficiency was more frequent in patients with urinary stone disease (P = 0.041, OR = 2.38). Although in the non- balding and mild balding Groups (Group I and Group II), presence of testosterone deficiency was also more frequent in patients with urinary stone disease, a statistically significant difference was not seen. Significantly, we found that the presence of testosterone deficiency was more frequent in patients with urinary stone disease and who had severe AGA.

Prevalence, Pathophysiology, and Management of Androgen Deficiency in Men with Metabolic Syndrome, Type 2 Diabetes Mellitus, or Both

The prevalence of type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) has increased in the United States over the past 40 years. These conditions, long linked with many cardiovascular complications, have recently been linked with androgen or testosterone deficiency in men. Several pathophysiologic hypotheses exist regarding this association, with the most widely reported a relationship to obesity and insulin resistance. Several randomized trials have confirmed that when testosterone replacement therapy is given to patients with T2DM, MetS, or both, metabolic parameters such as waist circumference, hemoglobin A1c , and systolic blood pressure are significantly reduced by up to 11 cm, 1.9%, and 23 mm Hg, respectively. This has not, however, resulted in improved cardiovascular outcomes, as evidenced in studies that found increased rates of cardiovascular events following testosterone replacement therapy. In this review, we summarize the relevant literature regarding the pathophysiology and management of androgen deficiency in men with T2DM, MetS, or both.

Impact of Diet-Induced Obesity and Testosterone Deficiency on the Cardiovascular System: A Novel Rodent Model Representative of Males with Testosterone-Deficient Metabolic Syndrome (TDMetS)

INTRODUCTION

Current models of obesity utilise normogonadic animals and neglect the strong relationships between obesity-associated metabolic syndrome (MetS) and male testosterone deficiency (TD). The joint presentation of these conditions has complex implications for the cardiovascular system that are not well understood. We have characterised and investigated three models in male rats: one of diet-induced obesity with the MetS; a second using orchiectomised rats mimicking TD; and a third combining MetS with TD which we propose is representative of males with testosterone deficiency and the metabolic syndrome (TDMetS).

METHODS

Male Wistar rats (n = 24) were randomly assigned to two groups and provided ad libitum access to normal rat chow (CTRL) or a high fat/high sugar/low protein "obesogenic" diet (OGD) for 28 weeks (n = 12/group). These groups were further sub-divided into sham-operated or orchiectomised (ORX) animals to mimic hypogonadism, with and without diet-induced obesity (n = 6/group). Serum lipids, glucose, insulin and sex hormone concentrations were determined. Body composition, cardiovascular structure and function; and myocardial tolerance to ischemia-reperfusion were assessed.

RESULTS

OGD-fed animals had 72% greater fat mass; 2.4-fold greater serum cholesterol; 2.3-fold greater serum triglycerides and 3-fold greater fasting glucose (indicative of diabetes mellitus) compared to CTRLs (all p<0.05). The ORX animals had reduced serum testosterone and left ventricle mass (p<0.05). In addition to the combined differences observed in each of the isolated models, the OGD, ORX and OGD+ORX models each had greater CK-MB levels following in vivo cardiac ischemia-reperfusion insult compared to CTRLs (p<0.05).

CONCLUSION

Our findings provide evidence to support that the MetS and TD independently impair myocardial tolerance to ischemia-reperfusion. The combined OGD+ORX phenotype described in this study is a novel animal model with associated cardiovascular risk factors and complex myocardial pathology which may be representative of male patients presenting with TDMetS.