Insulin Resistance and Inflammation in Hypogonadotropic Hypogonadism and Their Reduction After Testosterone Replacement in Men With Type 2 Diabetes

Novel perspectives of testosterone therapy in men with functional hypogonadism: traversing the gaps of knowledge

INTRODUCTION

In the past decade, there has been a significant augmentation in the corpus of evidence pertaining to functional hypogonadism. Despite this, prevailing clinical guidelines continue to advise against the universal screening for hypogonadism in middle-aged and elderly males.

FINDINGS

Numerous randomized controlled trials have scrutinized the effects of testosterone therapy in males afflicted with type 2 diabetes and/or obesity. However, these guidelines uniformly assert that lifestyle modifications and weight reduction should be the primary intervention strategies in overweight and obese males, relegating testosterone therapy to a secondary, selective option. It is extensively documented that testosterone therapy can yield substantial improvements in various metabolic parameters as well as ameliorate symptoms of erectile dysfunction. Moreover, recent studies have demonstrated the potential of testosterone therapy in reversing type 2 diabetes in males with low-normal testosterone levels who are at elevated risk for this condition, in comparison to the outcomes achievable through lifestyle modifications alone.

CONCLUSION

This focused review article aims to present a comprehensive update on the latest data concerning the innovative aspects of testosterone therapy in males with functional hypogonadism, particularly in the context of type 2 diabetes and/or obesity. Additionally, it will delve into the cardiovascular safety of such interventions within this high-risk demographic, with a special emphasis on insights gleaned from the TRAVERSE trial.

Diabetes surpasses obesity as a risk factor for low serum testosterone level

BACKGROUND

Male obesity is one of the most associated factors with substandard testosterone levels. However, there is growing evidence linking low testosterone levels to insulin resistance and diabetic complications. We aimed to study the impact of diabetes mellitus on testosterone levels and to assess the correlation of various clinical and biochemical factors with hypogonadism.

SUBJECTS AND METHODS

This case-control study was conducted on 160 adult males categorized into four equal groups (40 each); Group A: lean men with T2DM, Group B: obese with T2DM, Group C: lean with normal glycemic profile, Group D: obese with normal glycemic profile. Serum total testosterone (TT), SHBG and HbA1c have been measured. Free testosterone (cFT) and HOMA-IR were calculated.

RESULTS

A significant negative correlation of serum TT and cFTwith BMI (r -0.16, p 0.04/ r -0.26, p < 0.001, respectively) and with waist circumference (WC) (r -0.23, p 0.003 and r -0.3, p < 0.001, respectively). A significant decrease in TT and cFT in the diabetes group versus the non-diabetes one (p < 0.001 for both). TT level was significantly lower in the diabetic lean group than in the non-diabetic lean (p < 0.001), and even significantly lower than in the non-diabetic obese (p < 0.001). TT level in the diabetic obese group was lower than in the non-diabetic obese (p < 0.001). The same for cFT level, lower in the diabetic lean group than in non-diabetic lean (p < 0.001) and lower in the diabetic obese than in the non-diabetic obese (p < 0.001). Concomitant significant reduction in SHBG in the diabetes group (p < 0.001). Linear regression analysis revealed that TT significantly correlated with HOMA-IR. HOMA-IR with WC, age and the duration of diabetes correlated significantly with cFT. In our model, HOMA-IR and HbA1c accounted for approximately 51.3% of TT variability (adjusted R-squared 0.513).

CONCLUSIONS

The impact of T2DM on serum testosterone levels was more significant than that of obesity. Our study showed a decrease in SHBG together with cFT among the diabetes group. Hypogonadism is significantly correlated to insulin resistance and poor glycemic control, which implies another perspective on the impact of suboptimal glycemic control on the development of hypogonadism.

Glucose ingestion does not lower testosterone concentrations in men on testosterone therapy

Oral calorie intake causes an acute and transient decline in serum testosterone concentrations. It is not known whether this decline occurs in men on testosterone therapy. In this study, we evaluated the change in testosterone concentrations following oral glucose ingestion in hypogonadal men before and after treatment with testosterone therapy. This is a secondary analysis of samples previously collected from a study of hypogonadal men with type 2 diabetes who received testosterone therapy. Study participants (n = 14) ingested 75 grams of oral glucose, and blood samples were collected over 2 h. The test was repeated after 23 weeks of intramuscular testosterone therapy. The mean age and body mass index of study volunteers were 53 ± 8 years and 38 ± 7 kg/m2, respectively. Following glucose intake, testosterone concentrations fell significantly prior to testosterone therapy (week 0, p = 0.04). The nadir of testosterone concentration was at 1 h, followed by recovery to baseline by 2 h. In contrast, there was no change in testosterone concentrations at week 23. The change in serum testosterone concentrations at 60 min was significantly more at week 0 than week 23 (-11 ± 10% vs 0 ± 16%, p = 0.05). We conclude that oral glucose intake has no impact on testosterone concentrations in men on testosterone therapy. Endocrinology societies should consider clarifying in their recommendations that fasting testosterone concentrations are required for the diagnosis of hypogonadism, but not for monitoring testosterone therapy.

Chemerin regulates glucose and lipid metabolism by changing mitochondrial structure and function associated with androgen/androgen receptor

The adipokine chemerin contributes to exercise-induced improvements in glucose and lipid metabolism; however, the underlying mechanism remains unclear. We aimed to confirm the impact of reduced chemerin expression on exercise-induced improvement in glycolipid metabolism in male diabetic (DM) mice through exogenous chemerin administration. Furthermore, the underlying mechanism of chemerin involved in changes in muscle mitochondria function mediated by androgen/androgen receptor (AR) was explored by generating adipose-specific and global chemerin knockout (adipo-chemerin-/- and chemerin-/-) mice. DM mice were categorized into the DM, exercised DM (EDM), and EDM + chemerin supplementation groups. Adipo-chemerin-/- and chemerin-/- mice were classified in the sedentary or exercised groups and fed either a normal or high-fat diet. Exercise mice underwent a 6-wk aerobic exercise regimen. The serum testosterone and chemerin levels, glycolipid metabolism indices, mitochondrial function, and protein levels involved in mitochondrial biogenesis and dynamics were measured. Notably, exogenous chemerin reversed exercise-induced improvements in glycolipid metabolism, AR protein levels, mitochondrial biogenesis, and mitochondrial fusion in DM mice. Moreover, adipose-specific chemerin knockout improved glycolipid metabolism, enhanced exercise-induced increases in testosterone and AR levels in exercised mice, and alleviated the detrimental effects of a high-fat diet on mitochondrial morphology, biogenesis, and dynamics. Finally, similar improvements in glucose metabolism (but not lipid metabolism), mitochondrial function, and mitochondrial dynamics were observed in chemerin-/- mice. In conclusion, decreased chemerin levels affect exercise-induced improvements in glycolipid metabolism in male mice by increasing mitochondrial number and function, likely through changes in androgen/AR signaling.NEW & NOTEWORTHY Decreased chemerin levels affect exercise-induced improvements in glycolipid metabolism in male mice by increasing mitochondrial number and function, which is likely mediated by androgen/androgen receptor expression. This study is the first to report the regulatory mechanism of chemerin in muscle mitochondria.

Testosterone therapy reduces insulin resistance in men with adult-onset testosterone deficiency and metabolic syndrome. Results from the Moscow Study, a randomized controlled trial with an open-label phase

AIMS

To describe changes in homeostasis model assessment of insulin resistance index (HOMA-IR) following testosterone therapy in men with hypogonadism and metabolic syndrome (MetS).

MATERIALS AND METHODS

A randomized, placebo-controlled, double-blind randomized controlled trial (RCT) comprising 184 men with MetS and hypogonadism (testosterone undecanoate [TU]: 113 men, placebo: 71 men) was conducted. This was followed by an open-label phase in which all men were given TU. We focused on men who were not receiving antiglycaemic agents (TU: 81 men; placebo: 54 men) as these could affect HOMA-IR. Inter-group comparison of HOMA-IR was restricted to the RCT (30 weeks), whilst intra-group comparison was carried out on men provided TU during the RCT and open-label phases (study cohort) and men given placebo during the RCT and then switched to TU during the open-label phase (confirmatory cohort). Regression analysis was performed to identify factors associated with change in HOMA-IR (∆HOMA-IR).

RESULTS

The median HOMA-IR was significantly reduced at almost every time point (after 18 weeks) compared to baseline in men receiving TU in both the study and confirmatory cohorts. There was a significant decrease in median values of fasting glucose (30 weeks: -2.1%; 138 weeks: -4.9%) and insulin (30 weeks: -10.5%; 138 weeks: -35.5%) after TU treatment. Placebo was not associated with significant ∆HOMA-IR. The only consistent predictor of HOMA-IR decrease following TU treatment was baseline HOMA-IR (r2 ≥ 0.64).

CONCLUSIONS

Baseline HOMA-IR predicted ΔHOMA-IR, with a greater percentage change in insulin than in fasting glucose. In men with MetS/type 2 diabetes (T2DM) not on antiglycaemic therapy, improvements in HOMA-IR may be greater than suggested by change in fasting glucose. Our results suggest that hypogonadism screening be included in the management of men with MetS/T2DM.

Association of sex hormones with non-alcoholic fatty liver disease: An observational and Mendelian randomization study

BACKGROUND AND AIMS

Sex-specific associations of sex hormone-binding globulin (SHBG) and bioavailable testosterone (BAT) with NAFLD remain indeterminate. We aimed to explore observational and genetically determined relationships between each hormone and NAFLD.

METHODS

We included 187 395 men and 170 193 women from the UK Biobank. Linear and nonlinear Cox regression models and Mendelian randomization (MR) analysis were used to test the associations.

RESULTS

During 12.49 years of follow-up, 2209 male and 1886 female NAFLD cases were documented. Elevated SHBG levels were linearly associated with a lower risk of NAFLD in women (HR (95% CI), .71 (.63, .79)), but not in men (a "U" shape, pnon-linear < .001). Higher BAT levels were associated with a lower NAFLD risk in men (HR (95% CI), .81 (.71, .93)) but a higher risk in women (HR (95% CI): 1.25 (1.15, 1.36)). Genetically determined SHBG and BAT levels were linearly associated with NAFLD risk in women (OR (95% CI): .57 (.38, .87) and 2.21 (1.41, 3.26) respectively); in men, an "L-shaped" MR association between SHBG levels and NAFLD risk was found (pnon-linear = .016). The bidirectional MR analysis further revealed the effect of NAFLD on SHBG and BAT levels in both sexes.

CONCLUSIONS

Consistently, linear associations of lower SHBG and higher BAT levels with increased NAFLD risk were both conventionally and genetically found in women, while in men, SHBG acts in a nonlinear manner. In addition, NAFLD may affect SHBG and BAT levels.

Cardiovascular safety of testosterone replacement therapy in men: an updated systematic review and meta-analysis

INTRODUCTION

The cardiovascular (CV) safety of testosterone (T) replacement therapy (TRT) is still conflicting. Recent data suggested a TRT-related increased risk of atrial fibrillation (AF). The aim of this study was to systematic review and meta-analyze CV risk related to TRT as derived from placebo controlled randomized trials (RCTs).

AREAS COVERED

An extensive Medline, Embase, and Cochrane search was performed. All placebo-controlled RCTs reporting data on TRT-related CV safety were considered. To better analyze the role of T on AF, population-based studies investigating the relationship between endogenous circulating T levels and AF incidence were also included and analyzed.

EXPERT OPINION

Out of 3.615, 106 studies were considered, including 8.126 subjects treated with TRT and 7.310 patients allocated to placebo. No difference between TRT and placebo was observed when major adverse CV events were considered. Whereas the incidence of non-fatal arrhythmias and AF was increased in the only trial considering CV safety as the primary endpoint, this was not confirmed when all other studies were considered (MH-OR 1.61[0.84;3.08] and 1.44[0.46;4.46]). Similarly, no relationship between endogenous T levels and AF incidence was observed after the adjustment for confounders Available data confirm that TRT is safe and it is not related to an increased CV risk.

Incidence of Type 2 Diabetes Mellitus in Transgender Individuals Undergoing Gender Affirming Hormonal Therapy: A Systematic Review

Gender-affirming hormonal therapy (GAHT), which includes estrogen, testosterone, androgen agonists, is commonly used in transgender individuals to change their secondary sexual characteristics to align with their gender identity. However, this treatment could result in metabolic side effects that could increase the chances of acquiring type 2 diabetes mellitus. Thus, this study aims to compare differences in body mass index (BMI), insulin resistance, and the incidence of type 2 diabetes mellitus between cisgender and transgender individuals undergoing GAHT. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards, we conducted a systematic review searching through PubMed, Google Scholar, Medline (Medical Literature Analysis and Retrieval System Online), and ResearchGate for articles published between 2014 and 2024. The final search was conducted in February 2024. Out of the 3,934 articles reviewed, 11 were selected, focusing on insulin sensitivity/resistance, diabetes incidence, and BMI changes with GAHT. Although our result findings did not show clear evidence of increased diabetes incidence among GAHT patients, it was observed that GAHT does increase BMI and insulin resistance in transgender individuals. Notably, compared to transgender men, transgender women on GAHT were found to be more prone to insulin resistance. We recommend regularly monitoring insulin sensitivity parameters and HbA1c during GAHT to monitor metabolic side effects. Further research and more clinical trials are needed to confirm the GAHT's impact on insulin resistance and to evaluate its role in the onset of type 2 diabetes mellitus.

Effect of Testosterone on Progression From Prediabetes to Diabetes in Men With Hypogonadism: A Substudy of the TRAVERSE Randomized Clinical Trial

Importance

The effect of testosterone replacement therapy (TRT) in men with hypogonadism on the risk of progression from prediabetes to diabetes or of inducing glycemic remission in those with diabetes is unknown.

Objective

To evaluate the efficacy of TRT in preventing progression from prediabetes to diabetes in men with hypogonadism who had prediabetes and in inducing glycemic remission in those with diabetes.

Design, Setting, and Participants

This nested substudy, an intention-to-treat analysis, within a placebo-controlled randomized clinical trial (Testosterone Replacement Therapy for Assessment of Long-Term Vascular Events and Efficacy Response in Hypogonadal Men [TRAVERSE]) was conducted at 316 trial sites in the US. Participants included men aged 45 to 80 years with hypogonadism and prediabetes or diabetes who were enrolled in TRAVERSE between May 23, 2018, and February 1, 2022.

Intervention

Participants were randomized 1:1 to receive 1.62% testosterone gel or placebo gel until study completion.

Main Outcomes and Measures

The primary end point was the risk of progression from prediabetes to diabetes, analyzed using repeated-measures log-binomial regression. The secondary end point was the risk of glycemic remission (hemoglobin A1c level <6.5% [to convert to proportion of total hemoglobin, multiply by 0.01] or 2 fasting glucose measurements <126 mg/dL [to convert to mmol/L, multiply by 0.0555] without diabetes medication) in men who had diabetes.

Results

Of 5204 randomized participants, 1175 with prediabetes (mean [SD] age, 63.8 [8.1] years) and 3880 with diabetes (mean [SD] age, 63.2 [7.8] years) were included in this study. Mean (SD) hemoglobin A1c level in men with prediabetes was 5.8% (0.4%). Risk of progression to diabetes did not differ significantly between testosterone and placebo groups: 4 of 598 (0.7%) vs 8 of 562 (1.4%) at 6 months, 45 of 575 (7.8%) vs 57 of 533 (10.7%) at 12 months, 50 of 494 (10.1%) vs 67 of 460 (14.6%) at 24 months, 46 of 359 (12.8%) vs 52 of 330 (15.8%) at 36 months, and 22 of 164 (13.4%) vs 19 of 121 (15.7%) at 48 months (omnibus test P = .49). The proportions of participants with diabetes who experienced glycemic remission and the changes in glucose and hemoglobin A1c levels were similar in testosterone- and placebo-treated men with prediabetes or diabetes.

Conclusions and Relevance

In men with hypogonadism and prediabetes, the incidence of progression from prediabetes to diabetes did not differ significantly between testosterone- and placebo-treated men. Testosterone replacement therapy did not improve glycemic control in men with hypogonadism and prediabetes or diabetes. These findings suggest that TRT alone should not be used as a therapeutic intervention to prevent or treat diabetes in men with hypogonadism.

Trial Registration

ClinicalTrials.gov Identifier: NCT03518034.

The Effect of Testosterone Replacement Therapy on Nonalcoholic Fatty Liver Disease in Older Hypogonadal Men

CONTEXT

Male hypogonadism is associated with visceral obesity and the metabolic syndrome: factors important for the development of nonalcoholic fatty liver disease (NAFLD). The Testosterone Trials (The T Trials) showed testosterone (T) treatment compared with placebo in older hypogonadal men was associated with decreases in cholesterol and insulin levels suggesting that T treatment may improve NAFLD.

OBJECTIVE

Compare effects of T vs placebo treatment on NAFLD scores and liver scans in elderly hypogonadal men.

METHODS

Secondary data analyses from 479 older hypogonadal men with total T < 275 ng/dL from The T Trials were performed. Three clinical liver fat scores-lipid accumulation product index, hepatic steatosis index, nonalcoholic fatty liver disease-metabolic syndrome score-and liver computed tomography (CT) Hounsfield units and liver to spleen ratio were evaluated at baseline and 12 months after treatment.

RESULTS

There were no statistically significant differences of change in lipid accumulation product index (P = .98), hepatic steatosis index (P = .67), and nonalcoholic fatty liver disease-metabolic syndrome (P = .52) in 246 men treated with T compared with 233 treated with placebo for 12 months. Liver CT showed no statistically significant difference of change in Hounsfield units (P = .24; n = 71 for T, n = 69 for placebo) and liver to spleen ratio (P = .74; n = 55 for T, n = 62 for placebo) between the 2 groups.

CONCLUSIONS

Our study did not show improvement of NAFLD in older hypogonadal men after 12 months of T vs placebo treatment, as assessed by 3 clinical scores and liver CT for hepatic steatosis. Future studies with longer treatment duration and additional NAFLD diagnostic modalities as primary outcome are warranted.

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.

EMAS position statement: Testosterone replacement therapy in older men

INTRODUCTION

Late-onset hypogonadism is the clinical entity characterised by low testosterone concentrations associated with clinical symptoms in the absence of organic disease in ageing men. It has been associated with metabolic syndrome, reduced bone mineral density, and increased cardiovascular morbidity and mortality risk. Although testosterone replacement therapy (TRT) reverses most of these conditions in young hypogonadal men, the risk/benefit ratio of TRT in older men is debatable.

AIM

To update the 2015 EMAS statement on TRT in older men with new research on late-onset hypogonadism and TRT.

MATERIALS AND METHODS

Literature review and consensus of expert opinion.

SUMMARY RECOMMENDATIONS

TRT should be offered only to symptomatic older men with confirmed low testosterone concentrations after explaining the uncertainties regarding the long-term safety of this treatment. TRT may be offered to men with severe hypogonadism and erectile dysfunction to improve sexual desire, erectile, and orgasmic function. It should also be considered in hypogonadal men with severe insulin resistance or pre-diabetes mellitus. TRT may also be considered, in combination with proven treatment strategies, for osteoporosis, or for selected patients with persistent mild depressive symptoms and/or low self-perceived quality of life, combined with standard medical care for each condition. TRT is contraindicated in hypogonadal men actively seeking fertility treatment. Due to a lack of data, TRT should not be routinely used in older men to improve exercise capacity/physical function, improve cognitive function, or prevent cognitive decline. TRT must be avoided in older, frail men with known breast cancer or untreated prostate cancer and all men who have had myocardial infarction or stroke within the last four months, and those with severe or decompensated heart failure. The quality of evidence regarding patients with previous prostate cancer or cardiovascular disease is too low to draw definitive conclusions. Any limits on duration of use are arbitrary, and treatment should continue for as long as the man feels the benefits outweigh the risks for him, and decisions must be made on an individual basis. Withdrawal should be considered when hypogonadism is reversed after the resolution of underlying disorder. Short-acting transdermal preparations should be preferred for TRT initiation in older men, but injectable forms may be considered subsequently. Older men on TRT should be monitored at 3, 6, and 12 months after initiation and at least yearly thereafter, or earlier and more frequently if indicated. Evaluation should include assessment of the clinical response, and measurement of total testosterone, haematocrit, and prostate-specific antigen (PSA) concentrations. Bone density and/or quality should also be assessed. Obese and overweight patients should be encouraged to undergo lifestyle modifications, including exercise and weight loss, to increase endogenous testosterone.

Endocrine aspects of metabolic dysfunction-associated steatotic liver disease (MASLD): Beyond insulin resistance

While the association of metabolic dysfunction-associated steatotic liver disease (MASLD) with obesity and insulin resistance is widely appreciated, there are a host of complex interactions between the liver and other endocrine axes. While it can be difficult to definitively distinguish direct causal relationships and those attributable to increased adipocyte mass, there is substantial evidence of the direct and indirect effects of endocrine dysregulation on the severity of MASLD, with strong evidence that low levels of growth hormone, sex hormones, and thyroid hormone promote the development and progression of disease. The impact of steroid hormones, e.g. cortisol and dehydroepiandrosterone, and adipokines is much more divergent. Thoughtful assessment, based on individual risk factors and findings, and management of non-insulin endocrine axes is essential in the evaluation and management of MASLD. Multiple therapeutic options have emerged that leverage various endocrine axes to reduce the fibroinflammatory cascade in MASH.

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

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

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.

Sex differences in chronic liver disease and benign liver lesions

The epidemiology, natural history, and therapeutic responses of chronic liver diseases and liver lesions often vary by sex. In this review, we summarize available clinical and translational data on these aspects of the most common liver conditions encountered in clinical practice, including the potential contributions of sex hormones to the underlying pathophysiology of observed differences. We also highlight areas of notable knowledge gaps and discuss sex disparities in access to liver transplant and potential strategies to address these barriers. Given established sex differences in immune response, drug metabolism, and response to liver-related therapies, emerging clinical trials and epidemiological studies should prioritize dedicated analyses by sex to inform sex-specific approaches to liver-related care.

Advances in mitochondria-centered mechanism behind the roles of androgens and androgen receptor in the regulation of glucose and lipid metabolism

An increasing number of studies have reported that androgens and androgen receptors (AR) play important roles in the regulation of glucose and lipid metabolism. Impaired glucose and lipid metabolism and the development of obesity-related diseases have been found in either hypogonadal men or male rodents with androgen deficiency. Exogenous androgens supplementation can effectively improve these disorders, but the mechanism by which androgens regulate glucose and lipid metabolism has not been fully elucidated. Mitochondria, as powerhouses within cells, are key organelles influencing glucose and lipid metabolism. Evidence from both pre-clinical and clinical studies has reported that the regulation of glucose and lipid metabolism by androgens/AR is strongly associated with the impact on the content and function of mitochondria, but few studies have systematically reported the regulatory effect and the molecular mechanism. In this paper, we review the effect of androgens/AR on mitochondrial content, morphology, quality control system, and function, with emphases on molecular mechanisms. Additionally, we discuss the sex-dimorphic effect of androgens on mitochondria. This paper provides a theoretical basis for shedding light on the influence and mechanism of androgens on glucose and lipid metabolism and highlights the mitochondria-based explanation for the sex-dimorphic effect of androgens on glucose and lipid metabolism.

Safety and Efficacy of Testosterone Therapy on Musculoskeletal Health and Clinical Outcomes in Men: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials

OBJECTIVE

Age-related declines in muscle and bone, alongside a shift toward greater adiposity, contribute to falls and fracture risk. Testosterone is osteogenic, myogenic, and catabolic to fat. As such, we examined the effects of testosterone therapy on musculoskeletal health and clinical outcomes in men.

METHODS

Electronic databases (Medline, Embase, Web of Science, Central) were systematically searched for randomized controlled trials (RCTs) reporting on the effects of testosterone therapy versus placebo on any primary outcome (bone density, muscle mass, fat mass, muscle strength/physical performance) or secondary outcome (falls, fractures, disability, adverse events) in men (≥18 years). A random effects meta-regression examined the effects of testosterone on prespecified outcomes.

RESULTS

One thousand seven hundred twenty-eight men across 16 RCTs were included (mean age: 77.1 ± 7.6 years). Baseline mean serum testosterone ranged from 7.5 ± 0.3 to 18.9 ± 1.2 nmol/L. Compared to placebo, 6 months of testosterone therapy increased hip bone density and total lean mass, but effects for handgrip and total fat mass did not reach statistical significance. No significant effects of testosterone therapy on musculoskeletal outcomes were evident at 12 months. The limited number of RCTs reporting on adverse events/clinical outcomes, and the low incidence of these events across RCTs, prohibited statistical comparisons.

CONCLUSION

After 6 months, testosterone effectively increases hip bone density and total lean mass in men, but its effects are unclear for lumbar spine bone density and handgrip strength. Further, RCTs are needed to clarify the safety and efficacy of testosterone on musculoskeletal health and clinical outcomes.

Metabolic Abnormalities, Inflammatory Markers and Endothelial Dysfunction in Hyperprolactinemia due to Prolactinoma before and after Normalization of Serum Prolactin: A Prospective Case Control Study

Background

Hyperprolactinemia is associated with obesity, dyslipidemia, insulin resistance, and low-grade inflammation which may promote endothelial dysfunction (EnD). Limited work has been done on EnD in prolactinomas and we, therefore, studied serum markers of inflammation and EnD in patients with prolactinomas before and after treatment with dopamine agonists.

Methodology

Fifty-six treatment naïve patients with prolactinomas and fifty-three (apparently healthy age and sex-matched) controls were enrolled in the study and subjected to clinical assessment and laboratory investigations including blood glucose, total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, urea, creatinine, uric acid, erythrocyte sedimentation rate (ESR), highly sensitive C-reactive protein (hsCRP) and markers of EnD i.e., intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Patients were treated with a dopamine agonist (cabergoline) and parameters (like ESR, hsCRP, ICAM-1, and VCAM-1) were measured at 12 weeks.

Results

The majority of the patients (84%) were female, more than half (52%) had metabolic syndrome and over a third (36%) were obese. Blood glucose fasting, HbA1c, lipid fractions, ESR, hsCRP, ICAM-1, and VCAM-1 were significantly higher in patients than in controls. Median ICAM-1 was 1331.95 ng/ml (IQR 803.43-1825.99) in patients vs 753.04 ng/ml (IQR 402.04-871.55) in controls, P < 0.001 and median VCAM-1in patients was 971.35 ng/ml (IQR 695.03-1285.23) as against 634.56 ng/ml (IQR 177.49-946.50) in controls, p0.001. Serum ICAM-1 and VCAM-1 correlated positively with hsCRP. On multivariate regression analysis, serum hsCRP was the only significant predictor of change in ICAM-1 and VCAM-1. Normalization of serum PRL with CAB resulted in a significant decrease in metabolic parameters, ESR, hsCRP, ICAM-1, and VCAM-1.

Conclusion

Hyperprolactinemia because of prolactinoma is associated with EnD secondary to systemic inflammation and metabolic abnormalities which improve after treatment with DA.

Male Reproduction and Aging

Recent publications of well-conducted population studies have informed us that the syndromic prevalence of age-related low testosterone, also known as late-onset hypogonadism, is quite low. Several well-conducted trials in middle-aged and older men with age-related decline in testosterone levels have revealed that efficacy of testosterone therapy is modest with improvement in sexual function, mood, volumetric bone density, and anemia. Although select older men might benefit from testosterone therapy, its effect on prostate cancer risk and major adverse cardiovascular events remains unclear. The results of the ongoing TRAVERSE trial will likely provide important insights into these risks.

Biomarkers to Be Used for Decision of Treatment of Hypogonadal Men with or without Insulin Resistance

Male hypogonadism is a result of low testosterone levels, but patients could be insulin-sensitive (IS) or insulin-resistant (IR), showing different impaired metabolic pathways. Thus, testosterone coadministration, which is commonly used to reestablish testosterone levels in hypogonadism, must take into account whether or not insulin is still active. By comparing metabolic cycles recorded in IS and IR plasma before and after testosterone therapy (TRT), it is possible to know what metabolic pathways can be reactivated in the two different groups upon testosterone recovery, and it is possible to understand if antagonism or synergy exists between these two hormones. IS hypogonadism uses glycolysis, while IR hypogonadism activates gluconeogenesis through the degradation of branched-chain amino acids (BCAAs). Upon administration of testosterone, acceptable improvements are observed in IS patients, wherein many metabolic pathways are restored, while in IR patients, a reprogramming of metabolic cycles is observed. However, in both subgroups, lactate and acetyl-CoA increases significantly. In IS patients, lactate is used through the glucose-lactate cycle to produce energy, while in IR patients, both lactate and acetyl-CoA are metabolized into ketone bodies, which are used to produce energy. Thus, in IR patients, an ancestral molecular mechanism is activated to produce energy, mimicking insulin effects. Regarding lipids, in both groups, the utilization of fatty acids for energy (β-oxidation) is blocked, even after TRT; free fatty acids (FFAs) increase in the blood in IS patients, while they are incorporated into triglycerides in those with IR. In both subgroups of hypogonadism, supplementation of useful chemicals is recommended during and after TRT when metabolites are not restored; they are listed in this review.

Exenatide improves hypogonadism and attenuates inflammation in diabetic mice by modulating gut microbiota

With the rising incidence of diabetes and its onset at a younger age, the impact on the male reproductive system has gradually gained attention. Exenatide is a glucagon-like peptide-1 receptor agonist effective in the treatment of diabetes. However, its role in diabetes-induced reproductive complications has rarely been reported. The study aimed to investigate the mechanism by which exenatide improved diabetic hypogonadism by regulating gut microbiota (GM) mediated inflammation. C57BL/6J mice were equally divided into normal control (NC), diabetic model control (DM) and exenatide-treated (Exe) groups. Testicular, pancreatic, colonic, and fecal samples were collected to assess microbiota, morphologic damage, and inflammation. Exenatide significantly reduced the fasting blood glucose (FBG) level in diabetic mice, increased the testosterone level, ameliorated the pathological morphological damage of islet, colon, and testes, and reduced the expression of pro-inflammatory factors, tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6 in colon and testis. Furthermore, exenatide significantly reduced the abundance of some pathogenic bacteria, such as Streptococcaceae and Erysipelotrichaceae, and increased that of beneficial bacteria Akkermansia. Probiotics, such as Lactobacillus were negatively correlated with TNF-α, nuclear factor-kappa-B (NF-κB), IL-6, and FBG. Conditional pathogenic bacteria such as Escherichia/Shigella Streptococcus were positively correlated with TNF-α, NF-κB, IL-6, and FBG. The fecal bacteria transplantation experiment revealed that the abundance of pathogenic bacteria, Peptostreptococcaceae, significantly decreased from Exe group mice to pseudo-sterile diabetic mice, and the pathological damage to testes was also alleviated. These data suggested the protective effects of exenatide on male reproductive damage induced by diabetes by regulating GM.

Voiding function improves under long-term testosterone treatment (TTh) in hypogonadal men, independent of prostate size

BACKGROUND

Functional hypogonadism is a condition in which some, but not all, older men have low testosterone levels. Rather than chronological age per se, the causality of hypogonadism includes obesity and impaired general health (e.g., metabolic syndrome). An association between testosterone deficiency and lower urinary tract symptoms (LUTS) has been reported, yet due to prostate safety concerns, men with severe LUTS (IPSS score > 19) have invariably been excluded from entering testosterone trials. Irrespective, exogenous testosterone has not been demonstrated to cause de novo or worsen mild to moderate LUTS.

OBJECTIVE

This study investigated whether long-term testosterone therapy (TTh) could have a protective effect on improving the symptoms of LUTS in hypogonadal men. However, the exact mechanism by which testosterone exerts is beneficial effect remains uncertain.

PATIENTS AND METHODS

In this study 321 hypogonadal patients with an average age of 58.9 ± 9.52 years received testosterone undecanoate in 12-week intervals for 12 years. One hundred and forty-seven of these males had the testosterone treatment interrupted for a mean of 16.9 months before it was resumed. Total testosterone, International Prostate Symptom Scale (IPSS), post-voiding residual bladder volume and aging male symptoms (AMS) were measured over the study period.

RESULTS

Prior to TTh interruption, it was observed that testosterone stimulation improved the men's IPSS, AMS and post-voiding residual bladder volume, while their prostate volume significantly increased. During the TTh interruption, there was a significant worsening in these parameters, although the increase in prostate volume continued. When TTh was resumed, these effects were reversed, implying that hypogonadism may require lifelong treatment.

Treatment with Testosterone Therapy in Type 2 Diabetic Hypogonadal Adult Males: A Systematic Review and Meta-Analysis

Testosterone replacement therapy (TRT) has been used to treat hypogonadal males with type 2 diabetes mellitus (T2DM) for a long time, despite variable results. This meta-analysis examines TRT's role in hypogonadal males with T2DM. The databases PubMed, Embase, and Google Scholar were searched for relevant RCTs and observational studies. Estimated pooled mean differences (MDs) and relative risks with 95% confidence intervals were used to measure the effects of TRT (CIs). When compared to the placebo, TRT improves glycemic management by significantly reducing glycated hemoglobin (HBA1c) levels (WMD = -0.29 [-0.57, -0.02] p = 0.04; I2 = 89.8%). Additionally, it reduces the homeostatic model assessment levels of insulin resistance (WMD = -1.47 [-3.14, 0.19]; p = 0.08; I2 = 56.3%), fasting glucose (WMD = -0.30 [-0.75, 0.15]; p = 0.19; I2 = 84.4%), and fasting insulin (WMD = -2.95 [-8.64, 2.74]; however, these results are non-significant. On the other hand, HBA1c levels are significantly reduced with TRT; in addition, total testosterone levels significantly increase with testosterone replacement therapy (WMD = 4.51 [2.40, 6.61] p = 0.0001; I2 = 96.3%). Based on our results, we hypothesize that TRT can improve glycemic control and hormone levels, as well as lower total cholesterol, triglyceride, and LDL cholesterol levels while raising HDL cholesterol in hypogonadal type 2 diabetes patients. To this end, we recommend TRT for these patients in addition to standard diabetes care.

Clinical and epidemiological characteristics of male hypogonadism in type 2 diabetes in Russia: combined analysis of study data for the period 2005–2022

Background: Male hypogonadism is associated with type 2 diabetes mellitus (T2DM), therefore, it is of interest to study its clinical and epidemiological characteristics. These data are published, but their fragmentation and small sample sizes are a problem. A summary assessment of the combined primary data of the conducted studies will provide sufficient representativeness and will allow to extrapolate the results to the general Russian population with T2DM.

Aim: Assessment of the clinical and epidemiological characteristics and aggravating factors of male hypogonadism in T2DM in Russia.

Materials and methods: A Combining primary data (anamnesis, anthropometric indicators, laboratory tests) of full-design, cross-sectional, screening studies of hypogonadism in men with T2DM conducted on the territory of the Russian Federation in the period from 2005 to 2022. The groups were compared using the Mann-Whitney U-test for quantitative indicators and χ² with Yates’ correction for qualitative ones. Differences were considered statistically significant with p <0,05. The groups were compared using the Mann-Whitney U-test and χ² with Yates correction. Differences were considered statistically significant at p<0.05.

Results: Hypogonadism was detected in 893 of 1576 men (56,7%) with T2DM. Patients with hypogonadism were statistically significantly older, had higher body mass index (BMI), worse glycemic control than eugonadal men. There was ­statistically significantly higher prevalence of macroangiopathies and polyneuropathy in hypogonadal patients.

Conclusion: The prevalence of male hypogonadism in T2DM 56,7%. Its development is due to age, obesity, worse glycemic control. Hypogonadism syndrome is associated with the development of diabetic macroangiopathy and polyneuropathy. Severe violation of glycemic control (glycated hemoglobin (HbA1c) 10% or more) significantly reduces testosterone production and increases the prevalence of hypogonadism.

Testosterone therapy in diabetes and pre-diabetes

BACKGROUND

Type 2 diabetes mellitus and pre-diabetes are associated with reduced circulating testosterone levels. However, the role of testosterone replacement therapy in these patients is still conflicting.

OBJECTIVES

To summarize and critically analyze available data on the possible effect of testosterone administration in men with glucose abnormalities.

MATERIALS AND METHODS

A comprehensive systematic review was performed. When available, meta-analytic data were preferred. To better analyze the relationship between testosterone and the pre-diabetes condition, a systematic analysis was performed and the data obtained with the latter search were used for a meta-analytic approach. Finally, clinical data derived from a consecutive series of 4682 patients seeking medical care for sexual dysfunction at the University of Florence were also considered.

RESULTS

Patients with impaired fasting glucose were characterized by a 3 nmol/L lower level of total testosterone when compared to controls. Similarly, impaired fasting glucose was associated with a 1.8-fold increased risk of hypogonadism, when compared to subjects with normal glucose levels. Waist circumference and body mass index resulted as being the best predictors of reduced total testosterone levels. Secondary hypogonadism was two times higher in subjects with impaired fasting glucose when compared to rates observed in the general population. Testosterone replacement therapy was able to improve body composition, insulin resistance, and glucose profile both in impaired fasting glucose and type 2 diabetes mellitus whereas its role on body weight, lipid profile, and sexual function was less evident.

DISCUSSION AND CONCLUSION

Weight loss and physical activities are able to improve both metabolic profile and testosterone levels. The combined approach of testosterone replacement therapy and lifestyle modifications could be suggested in symptomatic hypogonadal men to better motivate patients to perform physical activity which can eventually result in weight loss as well as metabolic profile and sexual function improvement. Whether or not these approaches can prevent the development of type 2 diabetes mellitus from pre-clinical conditions requires more studies.

Sex-specific and hormone-related differences in vascular remodelling in atherosclerosis

Atherosclerosis, a lipid-driven inflammatory disease, is the main underlying cause of cardiovascular diseases (CVDs) both in men and women. Sex-related dimorphisms regarding CVDs and atherosclerosis were observed since more than a decade ago. Inflammatory mediators such as cytokines, but also endothelial dysfunction, vascular smooth muscle cell migration and proliferation lead to vascular remodelling but are differentially affected by sex. Each year a greater number of men die of CVDs compared with women and are also affected by CVDs at an earlier age (40-70 years old) while women develop atherosclerosis-related complications mainly after menopause (60+ years). The exact biological reasons behind this discrepancy are still not well-understood. From the numerous animal studies on atherosclerosis, only a few include both sexes and even less investigate and highlight the sex-specific differences that may arise. Endogenous sex hormones such as testosterone and oestrogen modulate the atherosclerotic plaque composition and the frequency of such plaques. In men, testosterone seems to act like a double-edged sword as its decrease with ageing correlates with an increased risk of atherosclerotic CVDs, while testosterone is also reported to promote inflammatory immune cell recruitment into the atherosclerotic plaque. In premenopausal women, oestrogen exerts anti-atherosclerotic effects, which decline together with its level after menopause resulting in increased CVD risk in ageing women. However, the interplay of sex hormones, sex-specific immune responses and other sex-related factors is still incompletely understood. This review highlights reported sex differences in atherosclerotic vascular remodelling and the role of endogenous sex hormones in this process.

Ectopic lipid metabolism in anterior pituitary dysfunction

Over the past decades, adapted lifestyle and dietary habits in industrialized countries have led to a progress of obesity and associated metabolic disorders. Concomitant insulin resistance and derangements in lipid metabolism foster the deposition of excess lipids in organs and tissues with limited capacity of physiologic lipid storage. In organs pivotal for systemic metabolic homeostasis, this ectopic lipid content disturbs metabolic action, thereby promotes the progression of metabolic disease, and inherits a risk for cardiometabolic complications. Pituitary hormone syndromes are commonly associated with metabolic diseases. However, the impact on subcutaneous, visceral, and ectopic fat stores between disorders and their underlying hormonal axes is rather different, and the underlying pathophysiological pathways remain largely unknown. Pituitary disorders might influence ectopic lipid deposition indirectly by modulating lipid metabolism and insulin sensitivity, but also directly by organ specific hormonal effects on energy metabolism. In this review, we aim to I) provide information about the impact of pituitary disorders on ectopic fat stores, II) and to present up-to-date knowledge on potential pathophysiological mechanisms of hormone action in ectopic lipid metabolism.

Recognizing the True Value of Testosterone Therapy in Health Care

There has been little recognition within the medical community of the health impact of testosterone (T) deficiency (TD), also known as hypogonadism, and the substantial benefits of testosterone therapy (TTh) on health and quality of life despite high-level clinical evidence. In a roundtable symposium, investigators summarized the contemporary evidence in several key clinical areas. TD negatively impacts human health and quality of life and is associated with increased mortality. Several studies have demonstrated that TTh in men with TD reduced all-cause and cardiovascular mortality. The longstanding belief that TTh is associated with increased prostate cancer (PCa) risk is contradicted by recent evidence, including multiple studies showing that TTh is associated with reduced PCa risk. Similarly, the weight of current evidence indicates the purported concern that TTh is associated with increased cardiovascular risk is incorrect. Normalization of physiological T reduces myocardial infarction, stroke, and deaths compared with men whose testosterone levels failed to normalize. In diabetic men TTh improves insulin resistance, and a large 2-year controlled study in men with abnormal glucose tolerance showed a substantially reduced rate of diabetes among men treated with TTh compared with untreated controls. Long-term TTh in diabetic men resulted in progressive improvements in obesity and insulin requirements, including a substantial number who experienced complete remission of diabetes. Finally, TTh has been shown to reduce severe outcomes with Covid-19 infection. These lines of evidence argue strongly for the need for greater awareness in the medical community of the impact of TD on health, and of the health benefits of TTh.

Obesity, type 2 diabetes, and testosterone in ageing men

In the absence of obesity, adverse lifestyle behaviours, and use of medication such as opioids serum testosterone concentrations decrease by only a minimal amount at least until very advanced age in most men. Obesity is heterogeneous in its phenotype, and it is the accumulation of excess adipose tissue viscerally associated with insulin resistance, dyslipidaemia, inflammation, hypothalamic leptin resistance and gliosis that underpins the functional hypogonadism of obesity. Both central (hypothalamic) and peripheral mechanisms are involved resulting in a low serum total testosterone concentration, while LH and FSH are typically in the normal range. Peripherally a decrease in serum sex hormone binding globulin (SHBG) concentration only partially explains the decrease in testosterone and there is increasing evidence for direct effects in the testis. Men with obesity associated functional hypogonadism and serum testosterone concentrations below 16 nmol/L are at increased risk of incident type 2 diabetes (T2D); high testosterone concentrations are protective. The magnitude of weight loss is linearly associated with an increase in serum testosterone concentration and with the likelihood of preventing T2D or reverting newly diagnosed disease; treatment with testosterone for 2 years increases the probability of a positive outcome from a lifestyle intervention alone by approximately 40%. Whether the additional favourable benefits of testosterone treatment on muscle mass and strength and bone density and quality in the long-term remains to be determined.

Adult- and late-onset male hypogonadism: the clinical practice guidelines of the Italian Society of Andrology and Sexual Medicine (SIAMS) and the Italian Society of Endocrinology (SIE)

PURPOSE

To provide the evidence-based recommendations on the role of testosterone (T) on age-related symptoms and signs remains.

METHODS

The Italian Society of Andrology and Sexual Medicine (SIAMS) and the and the Italian Society of Endocrinology (SIE) commissioned an expert task force to provide an updated guideline on adult-onset male hypogonadism. Derived recommendations were based on Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

RESULTS

Clinical diagnosis of adult-onset hypogonadism should be based on a combination of clinical and biochemical parameters. Testosterone replacement therapy (TRT) should be offered to all symptomatic subjects with hypogonadism after the exclusion of possible contraindications. T gels and the long-acting injectable T are currently available preparations showing the best efficacy/safety profile. TRT can improve all aspects of sexual function, although its effect is limited in more complicated patients. Body composition (reducing fat mass and increasing lean mass) is improved after TRT, either in subjects with or without metabolic syndrome or type 2 diabetes. Conversely, the role of TRT in improving glycometabolic control is more conflicting. TRT can result in increasing bone mineral density, particularly at lumbar site, but no information on fracture risk is available. Limited data support the use of TRT for improving other outcomes, including mood frailty and mobility.

CONCLUSIONS

TRT can improve sexual function and body composition particularly in less complicated adult and in aging subjects with hypogonadism. When hypogonadism is adequately diagnosed, T appropriately prescribed and subjects correctly followed up, no short-term increased risk of adverse events is observed. Longer and larger studies are advisable to better clarify TRT long-term efficacy/safety profile.

Changes in levels of testosterone, insulin sensitivity and metabolic profiles during GnRH therapy: Reciprocity between insulin sensitivity and pituitary responsiveness to GnRH in teenage and young male patients with congenital hypogonadotropic hypogonadism

OBJECTIVES

A direct evaluation of insulin sensitivity on pituitary response to gonadotropin relasing hormone (GnRH) has not been shown in congenital hypogonadotropic hypogonadism (CHH), despite a growing body of evidence in the association of testosterone concentrations with insulin sensitiviy. The objective of the study was to explore whether increased testosterone concentrations in men with CHH improve insulin sensitivity, or vice versa.

DESIGN

A retrospective study at a tertiary centre.

PATIENTS

Series of male CHH patients were included from Jannuary 2014 to December 2019.

MEASUREMENTS

Insulin sensitivity indices calculated from oral glucose tolerance test and steroid hormone levels were examined in 52 patients with newly diagnosed CHH and 22 healthy controls. Thirty-two of the 52 CHH patients received pulsatile GnRH therapy with follow-up every 3-6 months.

RESULTS

Compared to healthy controls, CHH patients had elevated 2 h post-load glucose, HbA1c, fasting insulin, HOMA of insulin resistance (HOMA-IR) and decreased Matsuda index and testosterone (p ≤ .01). The median follow-up for patients (n = 32) who received pulsatile GnRH therapy was 13.5 (11.3-24) months (432 person-months in total). GnRH therapy increased testosterone and Matsuda index (p ≤ .0001), whilst decreased platelet count (p = .04), leptin (p = .04), fasting glucose (p = .01) and HOMA-IR (p &lt; .0001) compared with baseline. The median treatment duration first time to reach the lower limit of normal testosterone concentrations of patients with high and low baseline insulin sensitivity was 15 (95% CI: 8.1-21.9) and 30 months (21.2-38.8), respectively. Correspondingly, after GnRH therapy, luteinizing hormone responsiveness to GnRH provocative test was more vigorous in patients with high insulin sensitivity than those with low insulin sensitivity [17.0 (9.5-25.9) vs. 8.2 (3.3-13.0), p = .01].

CONCLUSION

Pulsatile GnRH therapy elevated testosterone levels in male CHH patients, ameliorated impaired insulin sensitivity and attenuated subclinical inflammatory response, increased insulin sensitivity, in turn, may benefit the efficacy of pulsatile GnRH therapy.

Testosterone replacement therapy and cardiovascular disease

The use of testosterone therapy has a complex history of apprehension and questions regarding its safety. Despite an eventual consensus that testosterone therapy was safe and effective, several studies relating to cardiovascular risks emerged in the last decade, rekindling skepticism regarding the safety of testosterone therapy. Given the utility of testosterone therapy in treating the symptoms of hypogonadism, it remains crucial to closely examine the safety of testosterone therapy. The present article synthesizes the current evidence regarding cardiovascular risks that may be associated with testosterone therapy, the potential mechanisms regarding testosterone's efficacy, and future directions in evaluating the safety of its use.

Impact of Adjunct Testosterone on Cancer-Related Fatigue: An Ancillary Analysis from a Controlled Randomized Trial

Many cancer patients undergoing treatment experience cancer-related fatigue (CRF). Inflammatory markers are correlated with CRF but are not routinely targeted for treatment. We previously demonstrated in an NIH-funded placebo-controlled, double-blind, randomized clinical trial (NCT00878995, closed to follow-up) that seven weekly injections of 100 mg adjunct testosterone preserved lean body mass in cancer patients undergoing standard-of-care treatment in a hospital setting. Because testosterone therapy can reduce circulating proinflammatory cytokines, we conducted an ancillary analysis to determine if this testosterone treatment reduced inflammatory burden and improved CRF symptoms and health-related quality of life. Randomization was computer-generated and managed by the pharmacy, which dispensed testosterone and placebo in opaque syringes to the administering study personnel. A total of 24 patients were randomized (14 placebo, 10 testosterone), and 21 were included in the primary analysis (11 placebo, 10 testosterone). Testosterone therapy did not ameliorate CRF symptoms (placebo to testosterone difference in predicted mean multidimensional fatigue symptom inventory scores: -5.6, 95% CI: -24.6 to 13.3), improve inflammatory markers, or preserve health-related quality of life and functional measures of performance in late-stage cancer patients.

On the Need to Distinguish between Insulin-Normal and Insulin-Resistant Patients in Testosterone Therapy

Male hypogonadism is a disorder characterized by low levels of the hormone testosterone and patients may also have insulin sensitivity (IS) or insulin resistance (IR), such that they show different clinical complications and different metabolic pathways. In this review, we compare metabonomic differences observed between these two groups before and after testosterone therapy (TRT) in order to obtain information on whether the two hormones testosterone and insulin are synergistic or antagonistic. IS hypogonadism uses glucose as the main biofuel, while IR activates gluconeogenesis by the degradation of branched-chain amino acids. The Krebs (TCA) cycle is active in IS but connected with glutaminolysis, while in IR the TCA cycle stops at citrate, which is used for lipogenesis. In both cases, the utilization of fatty acids for energy (β-oxidation) is hampered by lower amounts of acetylcarnitine, although it is favored by the absence of insulin in IR. Increased free fatty acids (FFAs) are free in the blood in IS, while they are partially incorporated in triglycerides in IR. Thus, upon TRT, the utilization of glucose is increased more in IS than in IR, revealing that in IR there is a switch from preferential glucose oxidation to lipid oxidation. However, in both cases, a high production of lactate and acetyl-CoA is the final result, with these levels being much higher in IR. Lactate is used in IS in the glucose–lactate cycle between the liver and muscle to produce energy, while in IR lactate and acetyl-CoA are biotransformed into ketone bodies, resulting in ketonuria. In conclusion, the restoration of testosterone values in hypogonadism gives better results in IS than in IR patients: in IS, TRT restores most of the metabolic pathways, while in IR TRT impairs insulin, and when insulin is inactive TRT activates an ancestral molecular mechanism to produce energy. This evidence supports the hypothesis that, over time, hypogonadism switches from IS to IR, and in the latter case most of the insulin-related metabolisms are not reactivated, at least within 60 days of TRT. However, testosterone therapy in both IS and IR might be of benefit given supplementation with metabolites that are not completely restored upon TRT, in order to help restore physiological metabolisms. This review underlines the importance of using a systems biology approach to shed light on the molecular mechanisms of related biochemical pathways involving insulin and testosterone.

Association of Male Hypogonadism With Risk of Hospitalization for COVID-19

IMPORTANCE

Male sex is associated with severe COVID-19. It is not known whether the risk of hospitalization differs between men with hypogonadism, men with eugonadism, and those receiving testosterone therapy (TTh).

OBJECTIVE

To compare COVID-19 hospitalization rates for men with hypogonadism who were not receiving TTh, men with eugonadism, and men receiving TTh.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted in 2 large academic health systems in St Louis, Missouri, among 723 men with a history of COVID-19 who had testosterone concentrations measured between January 1, 2017, and December 31, 2021.

EXPOSURES

The primary exposure was gonadal status (hypogonadism, eugonadism, and TTh). Hypogonadism was defined as a total testosterone concentration below the limit of normal provided by the laboratory (which varied from 175 to 300 ng/dL [to convert to nanomoles per liter, multiply by 0.0347]).

MAIN OUTCOMES AND MEASURES

The primary outcome was rate of hospitalization for COVID-19. Statistical adjustments were made for group differences in age, body mass index, race and ethnicity, immunosuppression, and comorbid conditions.

RESULTS

Of the 723 study participants (mean [SD] age, 55 [14] years; mean [SD] body mass index, 33.5 [7.3]), 116 men had hypogonadism, 427 had eugonadism, and 180 were receiving TTh. Men with hypogonadism were more likely than men with eugonadism to be hospitalized with COVID-19 (52 of 116 [45%] vs 53 of 427 [12%]; P < .001). After multivariable adjustment, men with hypogonadism had higher odds than men with eugonadism of being hospitalized (odds ratio, 2.4; 95% CI, 1.4-4.4; P < .003). Men receiving TTh had a similar risk of hospitalization as men with eugonadism (odds ratio, 1.3; 95% CI, 0.7-2.3; P = .35). Men receiving inadequate TTh (defined as subnormal testosterone concentrations while receiving TTh) had higher odds of hospitalization compared with men who had normal testosterone concentrations while receiving TTh (multivariable adjusted odds ratio, 3.5; 95% CI, 1.5-8.6; P = .003).

CONCLUSIONS AND RELEVANCE

This study suggests that men with hypogonadism were more likely to be hospitalized after COVID-19 infection compared with those with eugonadism, independent of other known risk factors. This increased risk was not observed among men receiving adequate TTh. Screening and appropriate therapy for hypogonadism need to be evaluated as a strategy to prevent severe COVID-19 outcomes among men.

Effects of testosterone therapy in adult males with hypogonadism and T2DM: A meta-analysis and systematic review

BACKGROUND AND AIMS

Testosterone supplementation therapy (TST) is a longstanding treatment for hypogonadal men with type 2 diabetes mellitus (T2DM), even though the benefits of TST are variable among trials. This meta-analysis was done to determine the specific role of TST in hypogonadal men with T2DM.

METHODS

PubMed, Embase, and Google Scholar were queried to discover eligible randomized controlled trials (RCTs) and observational studies. To quantify the specific effects of TST, we estimated pooled mean differences (MDs) and relative risks with 95% confidence intervals (CIs).

RESULTS

Our meta-analysis included 1596 hypogonadal T2DM subjects from 12 randomized controlled trials and one observational study. TST can significantly enhance glycemic control compared to placebo by decreasing homeostatic model assessment of insulin resistance (WMD = -1.55 [-2.65, -0.45]; p = 0.26; I2 = 20.2%), fasting glucose (WMD = -0.35 [-0.79, 0.10]; p = 0.07; I2 = 69.7%), fasting insulin (WMD = -2.88 [-6.12, 0.36]; p = In addition, TST can decrease cholesterol (WMD = -0.28 [-0.47, -0.09] p = 0.0008; I2 = 91%) and triglyceride (WMD = -0.23 [-0.43, -0.03] p = 0.03; I2 = 79.2%). Furthermore, Testosterone therapy is related to a significant rise in total testosterone levels (WMD = 5.08 [2.90, 7.26] p = 0.0002; I2 = 92.9%). Pooling of free testosterone levels indicated a larger increase in the patients who got TST than placebo (WMD = 81.21 [23.87, 138.54] p = 0.07; I2 = 70%).

CONCLUSION

Our findings suggested that TST can enhance glycemic control and hormone levels and reduce total cholesterol, triglyceride, LDL cholesterol whereas increase HDL cholesterol in hypogonadal T2DM patients. Therefore, in these patients, we propose TST alongside anti-diabetic treatment.

Plasma Metabonomics in Insulin-Resistant Hypogonadic Patients Induced by Testosterone Treatment

Hypogonadic subjects with insulin resistance (IR) showed different metabonomic profiles compared to normo-insulinemic subjects (IS). Testosterone replacement therapy (TRT) may have a different impact on the metabolisms of those with the presence or absence of insulin resistance. We evaluated the changes in the metabolism of IR hypogonadic patients before and after 60 days of TRT. The metabonomic plasma profiles from 20 IR hypogonadal patients were recorded using ultra-high-performance liquid chromatography (UHPLC) and high-resolution mass spectrometry (HRMS). Plasma metabolites, before and after 60 days of TRT, were compared. In hypogonadic patients, carnosine, which is important for improving performance during exercise, increased. Conversely, proline and lysine—amino acids involved in the synthesis of collagen—reduced. Triglycerides decreased and fatty acids (FFAs) increased in the blood as a consequence of reduced FFA β-oxidation. Glycolysis slightly improved, while the Krebs cycle was not activated. Gluconeogenesis (which is the main energy source for hypogonadal IR before TRT) stopped after treatment. As a consequence, lactate and acetyl CoA increased significantly. Both lactate and acetyl CoA were metabolized into ketone bodies which increased greatly, also due to leucine/isoleucine degradation. Ketone bodies were derived predominantly from acetyl CoA because the reaction of acetyl CoA into ketone bodies is catalyzed by mtHMGCoA synthase. This enzyme is inhibited by insulin, which is absent in IR patients but overexpressed following testosterone administration. Ketosis is an alternative route for energy supply and provides the same metabolic effects as insulin but at the metabolic or primitive control level, which bypasses the complex signaling pathway of insulin. After treatment, the hypogonadic patients showed clinical symptoms related to ketonuria. They presented similarly to those following a ketogenic diet, the so-called ‘keto flu’. This must be taken into account before the administration of TRT to hypogonadic patients.

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.

Testosterone therapy reduces hepatic steatosis in men with type 2 diabetes and low serum testosterone concentrations

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent in people with diabetes with no available treatment.

AIM

To explore the effect of testosterone treatment on liver. Testosterone therapy improves insulin resistance and reduces total body fat, but its impact on the liver remains poorly studied.

METHODS

This secondary analysis of a 40 wk, randomised, double-blinded, placebo-controlled trial of intramuscular testosterone undecanoate in men with type 2 diabetes and lowered serum testosterone concentrations evaluated the change in hepatic steatosis as measured by liver fat fraction on magnetic resonance imaging (MRI).

RESULTS

Of 88 patients enrolled in the index study, 39 had liver MRIs of whom 20 received testosterone therapy and 19 received placebo. All patients had > 5% hepatic steatosis at baseline and 38 of 39 patients met diagnostic criteria for NAFLD. Median liver fat at baseline was 15.0% (IQR 11.5%-21.1%) in the testosterone and 18.4% (15.0%-28.9%) in the placebo group. Median ALT was 34units/L (26-38) in the testosterone and 32units/L (25-52) in the placebo group. At week 40, patients receiving testosterone had a median reduction in absolute liver fat of 3.5% (IQR 2.9%-6.4%) compared with an increase of 1.2% in the placebo arm (between-group difference 4.7% P < 0.001). After controlling for baseline liver fat, testosterone therapy was associated with a relative reduction in liver fat of 38.3% (95% confidence interval 25.4%-49.0%, P < 0.001).

CONCLUSION

Testosterone therapy was associated with a reduction in hepatic steatosis in men with diabetes and low serum testosterone. Future randomised studies of testosterone therapy in men with NAFLD focusing on liver-related endpoints are therefore justified.

The Effects of Testosterone Treatment on Cardiovascular Health

Current evidence suggests that testosterone therapy has numerous benefits and risks on cardiovascular health. Examples of this include published data that support improvements in insulin sensitivity and body composition which may reduce the risk of diabetes. On the other hand, testosterone therapy may offset such benefits by mild impairments in lipid parameters. Consequently, controversy on the effects of testosterone therapy on cardiovascular health remains. Studies are underway to clarify this important question for the benefit of men with hypogonadism.

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.

Sex hormones, adiposity, and metabolic traits in men and women: a Mendelian randomisation study

OBJECTIVE

Epidemiological and clinical studies have highlighted important roles for sex hormones in the regulation of fat distribution and systemic metabolism. We investigated the bidirectional associations between bioavailable serum testosterone (BioT) in both sexes and oestradiol (E2) in men and adiposity and metabolic traits using Mendelian randomisation (MR).

DESIGN AND METHODS

As genetic instruments for sex hormones, we selected all the genome-wide significant, independent signals from a genome-wide association studies (GWAS) in up to 425 097 European ancestry UK Biobank participants. European population-specific, summary-level data for adiposity, metabolic, and blood pressure traits were obtained from the largest publicly available GWAS. Sex-specific, two-sample MR analyses were used to estimate the associations of sex hormones with these traits and vice versa.

RESULTS

In women, higher BioT was associated with obesity, upper-body fat distribution, and low HDL-cholesterol although, based on analyses modelling the sex hormone-binding globulin-independent effects of BioT, the last two associations might be indirect. Conversely, obesity and android fat distribution were associated with elevated serum BioT. In men, higher BioT was associated with lower hip circumference and lower fasting glucose. Reciprocally, obesity was associated with lower BioT and higher E2, while upper-body fat distribution and raised triglycerides were associated with lower E2.

CONCLUSIONS

Adipose tissue and metabolic dysfunction are associated with deranged sex hormone levels in both sexes. In women, elevated BioT might be a cause of obesity. Conversely, in men, higher BioT appears to have beneficial effects on adiposity and glucose metabolism.

Biomarkers of glucose homeostasis and inflammation with risk of prostate cancer: A case-cohort study

BACKGROUND

Few prospective studies have examined biomarkers of glucose homeostasis or inflammation with prostate cancer risk by tumor stage or grade.

METHODS

We conducted a case-cohort study to examine associations of pre-diagnosis hemoglobin A1c (HbA1c), c-peptide, and c-reactive protein (CRP) with prostate cancer risk overall and stratified by tumor stage and grade. The study included 390 non-aggressive (T1-2, N0, M0 and Gleason score <8) and 313 aggressive cases (T3-4, or N1, or M1, or Gleason score 8-10) diagnosed after blood draw (1998-2001) and up to 2013, and a random sub-cohort of 1,303 cancer-free men at blood draw in the Cancer Prevention Study-II Nutrition Cohort. Prentice-weighted Cox proportional hazards regression models were used to estimate hazards ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

In the multivariable-adjusted model without body mass index (BMI), HbA1c was inversely associated with non-aggressive prostate cancer (HR per unit increase: 0.89, 95% CI: 0.80-1.00, P=0.04). Analyses stratified by tumor stage and grade separately showed that HbA1c was inversely associated with low-grade prostate cancer (HR per unit increase: 0.89, 95% CI: 0.80-1.00) and positively associated with high-grade prostate cancer (HR per unit increase: 1.15, 95% CI: 1.01-1.30). C-peptide and CRP were not associated with prostate cancer overall or by stage or grade.

CONCLUSIONS

The present study suggests that associations of hyperglycemia with prostate cancer may differ by tumor grade and stage.

IMPACT

Future studies need to examine prostate cancer by tumor stage and grade, and to better understand the role of hyperglycemia in prostate cancer progression.

Low-grade inflammation in survivors of childhood cancer and testicular cancer and its association with hypogonadism and metabolic risk factors

Background

In childhood (CCS) and testicular cancer (TCS) survivors, low-grade inflammation may represent a link between testosterone deficiency (hypogonadism) and risk of metabolic syndrome. We aimed to study levels of inflammatory markers in CCS and TCS and the association with hypogonadism and future cardio-metabolic risk factors.

Methods

Serum levels of inflammatory markers and testosterone were analyzed in CCS (n = 90), and TCS (n = 64, median time from diagnosis: 20 and 2.0 years, respectively), and in controls (n = 44). Differences in levels between patients and controls were calculated using univariate analysis of variance. T-test and logistic regression were applied to compare levels of cardio-metabolic risk factors and odds ratio (OR) of hypogonadism and metabolic syndrome in low and high inflammatory marker groups after 4–12 years of follow up. Adjustment for age, smoking, and active cancer was made.

Results

TCS and CCS, as compared to controls, had 1.44 (95%CI 1.06–1.96) and 1.25 (95 CI 1.02–1.53) times higher levels of IL-8, respectively. High IL-6 levels were associated with hypogonadism at baseline (OR 2.83, 95%CI 1.25–6.43) and the association was stronger for high IL-6 combined with low IL-10 levels (OR 3.10, 95%CI 1.37–7.01). High IL-6 levels were also associated with higher BMI, waist circumference, insulin, and HbA1c at follow up. High TNF-α was associated with higher diastolic blood pressure. No individual inflammatory marker was significantly associated with risk of metabolic syndrome at follow up. High IL-6 combined with low IL-10 levels were associated with risk of metabolic syndrome (OR 3.83, 95%CI 1.07–13.75), however not statistically significantly after adjustment.

Conclusion

TCS and CCS present with low-grade inflammation. High IL-6 levels were associated with hypogonadism and cardio-metabolic risk factors. Low IL-10 levels might reinforce the IL-6 mediated risk of developing metabolic syndrome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09253-5.

Erectile dysfunction and diabetes: A melting pot of circumstances and treatments

Diabetes mellitus (DM), a chronic metabolic disease characterised by elevated levels of blood glucose, is among the most common chronic diseases. The incidence and prevalence of DM have been increasing over the years. The complications of DM represent a serious health problem. The long-term complications include macroangiopathy, microangiopathy and neuropathy as well as sexual dysfunction (SD) in both men and women. Erectile dysfunction (ED) has been considered the most important SD in men with DM. The prevalence of ED is approximately 3.5-fold higher in men with DM than in those without DM. Common risk factors for the development of DM and its complications include sedentary lifestyle, overweight/obesity and increased caloric consumption. Although lifestyle changes may help improve sexual function, specific treatments are often needed. This study aims to review the definition and prevalence of ED in DM, the impact of DM complications and DM treatment on ED and, finally, the current and emerging therapies for ED in patients with DM.

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.

Baseline Testosterone Predicts Body Composition and Metabolic Response to Testosterone Therapy

CONTEXT

Male hypogonadism adversely affects body composition, bone mineral density (BMD), and metabolic health. A previous report showed that pre-treatment testosterone (T) levels of <200 ng/dl is associated with greater improvement in spine BMD with T therapy. However, to date, there is no study that investigates whether baseline T levels also influence body composition and metabolic response to T therapy.

OBJECTIVE

The aim of this study is to determine if there are differences in the changes in body composition, metabolic profile, and bone turnover markers, in addition to BMD, in response to T therapy in men with a baseline T level of <264 ng/dl compared to those with levels ≥264 ng/dl.

METHODS

This is a secondary analysis of a single-arm, open-label clinical trial (NCT01378299) on pharmacogenetics of response to T therapy conducted between 2011 and 2016 involving 105 men (40-74 years old), with average morning T < 300 ng/dl, given intramuscular T cypionate 200 mg every 2 weeks for 18 months. Subjects were divided into those with baseline T levels of <264 ng/dl (N = 43) and those with ≥264 ng/dl (N = 57). T and estradiol (E2) were measured by liquid chromatography/mass spectrometry; serum bone turnover markers (C-telopeptide [CTX], osteocalcin, and sclerostin), adiponectin, and leptin were measured by enzyme-linked immunosorbent assay; glycated hemoglobin (HbA1c) was measured by high-performance liquid chromatography; and areal BMD and body composition was measured by dual-energy x-ray absorptiometry (DXA).

RESULTS

Men with T < 264 ng/dl showed greater increases in total fat-free mass (FFM) at 18 months compared to those with T ≥ 264 ng/dl (4.2 ± 4.1 vs. 2.7 ± 3.8%; p = 0.047) and unadjusted appendicular FFM at 6 and 18 months (8.7 ± 11.5 vs. 4.4 ± 4.3%, 7.3 ± 11.6 vs. 2.4 ± 6.8%; p = 0.033 and p = 0.043, respectively). Men with T ≥ 264 ng/dl showed significant decreases in HbA1c at 12 months (-3.1 ± 9.2 vs. 3.2 ± 13.9%; p = 0.005), fasting glucose at 18 months (-4.2 ± 31.9 vs. 13.0 ± 57.3%; p = 0.040), LDL at 6 months (-6.4 ± 27.5 vs. 12.8 ± 44.1%; p = 0.034), and leptin at 18 months (-40.2 ± 35.1 vs. -27.6 ± 31.0%; p = 0.034) compared to those with T < 264 ng/dl. No significant differences in BMD and bone turnover markers were observed.

CONCLUSION

T therapy results in improvement in body composition irrespective of baseline T levels but T < 264 ng/dl is associated with greater improvement in FFM, whereas a T level of ≥264 ng/dl favors improvement in metabolic profile.

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.