Clinical review: Why is androgen replacement in males controversial?

From mitochondria to sarcopenia: role of 17β-estradiol and testosterone

Sarcopenia, characterized by a loss of muscle mass and strength with aging, is prevalent in older adults. Although the exact mechanisms underlying sarcopenia are not fully understood, evidence suggests that the loss of mitochondrial integrity in skeletal myocytes has emerged as a pivotal contributor to the complex etiology of sarcopenia. Mitochondria are the primary source of ATP production and are also involved in generating reactive oxygen species (ROS), regulating ion signals, and initiating apoptosis signals in muscle cells. The accumulation of damaged mitochondria due to age-related impairments in any of the mitochondrial quality control (MQC) processes, such as proteostasis, biogenesis, dynamics, and mitophagy, can contribute to the decline in muscle mass and strength associated with aging. Interestingly, a decrease in sex hormones (e.g., 17β-estradiol and testosterone), which occurs with aging, has also been linked to sarcopenia. Indeed, 17β-estradiol and testosterone targeted mitochondria and exhibited activities in regulating mitochondrial functions. Here, we overview the current literature on the key mechanisms by which mitochondrial dysfunction contribute to the development and progression of sarcopenia and the potential modulatory effects of 17β-estradiol and testosterone on mitochondrial function in this context. The advance in its understanding will facilitate the development of potential therapeutic agents to mitigate and manage sarcopenia.

Morbidity and mortality in men: Role of androgens

In this narrative review we provide an overview of the current literature on male hypogonadism and related comorbidities, also depicting the role of testosterone therapy (TTh) in the various settings. Male hypogonadism has been associated with major comorbidities such as type 2 diabetes mellitus, obesity and cardiovascular diseases, promoting a vicious cycle that may lead to further hypogonadism. The biological underpinnings of this association are currently under investigations, but clearly emerges the relevance of the hypothalamic-pituitary-gonadal axis. Hypogonadism has also been associated with increased risk of mortality. As such, TTh has the potential to oppose these patterns and improve cardiovascular and metabolic health in hypogonadal men. Clinical and observational data suggest that in males with hypogonadism, TTh, together with lifestyle changes and diabetes medications, may improve glycemia, reduce risk of progression to diabetes and provides positive effects on cardiovascular risk. Conversely, available data does not fully support any increased risk of prostate cancer in men under TTh. Of clinical relevance, a possible harmful role of hypogonadal status in men with COVID-19 eventually emerged.

Risks of Serious Injury with Testosterone Treatment

BACKGROUND

Injury causes significant morbidity and mortality that is sometimes attributed to testosterone and violence. We hypothesized that prescribed testosterone might be associated with the subsequent risk of serious injury.

METHODS

We conducted a self-matched individual-patient exposure-crossover analysis comparing injury risks before and after initiation of testosterone. We selected adults treated with testosterone in Ontario, Canada, from October 1, 2012, to October 1, 2017 (enrollment) and continued until October 1, 2018 (follow-up). The primary outcome was defined as an acute traumatic event that required emergency medical care.

RESULTS

A total of 64,386 patients were treated with testosterone of whom 89% were men with a median age of 52 years. We identified 34,439 serious injuries during the baseline interval before starting testosterone (584 per month) and 7349 serious injuries during the subsequent interval after starting testosterone (565 per month). Rates of injuries were substantially above the population norm in both intervals with no significant increased risk after starting testosterone (relative risk = 1.00; 95% confidence interval: 0.96-1.04, P = 0.850). The unchanged risk extended to diverse patients, was observed for different formulations and applied to all injury mechanisms. In contrast, testosterone treatment was associated with a 48% increased risk of a thromboembolic event (relative risk = 1.48; 95% confidence interval: 1.25-1.74, P < 0.001).

CONCLUSIONS

Testosterone treatment was associated with a substantial baseline risk of serious injury that did not increase further after starting therapy. Physicians prescribing testosterone could consider basic safety reminders to mitigate injury risks.

Midlife Chronological and Endocrinological Transitions in Brain Metabolism: System Biology Basis for Increased Alzheimer's Risk in Female Brain

Decline in brain glucose metabolism is a hallmark of late-onset Alzheimer’s disease (LOAD). Comprehensive understanding of the dynamic metabolic aging process in brain can provide insights into windows of opportunities to promote healthy brain aging. Chronological and endocrinological aging are associated with brain glucose hypometabolism and mitochondrial adaptations in female brain. Using a rat model recapitulating fundamental features of the human menopausal transition, results of transcriptomic analysis revealed stage-specific shifts in bioenergetic systems of biology that were paralleled by bioenergetic dysregulation in midlife aging female brain. Transcriptomic profiles were predictive of outcomes from unbiased, discovery-based metabolomic and lipidomic analyses, which revealed a dynamic adaptation of the aging female brain from glucose centric to utilization of auxiliary fuel sources that included amino acids, fatty acids, lipids, and ketone bodies. Coupling between brain and peripheral metabolic systems was dynamic and shifted from uncoupled to coupled under metabolic stress. Collectively, these data provide a detailed profile across transcriptomic and metabolomic systems underlying bioenergetic function in brain and its relationship to peripheral metabolic responses. Mechanistically, these data provide insights into the complex dynamics of chronological and endocrinological bioenergetic aging in female brain. Translationally, these findings are predictive of initiation of the prodromal / preclinical phase of LOAD for women in midlife and highlight therapeutic windows of opportunity to reduce the risk of late-onset Alzheimer’s disease.

Hypogonadism, Type-2 Diabetes Mellitus, and Bone Health: A Narrative Review

One of the complications from chronic hyperglycemia and insulin resistance due to type 2 diabetes mellitus (T2DM) on the hypothalamic-pituitary-gonadal axis in men is the high prevalence of hypogonadotropic hypogonadism (HH). Both T2DM and hypogonadism are associated with impaired bone health and increased fracture risk but whether the combination results in even worse bone disease than either one alone is not well-studied. It is possible that having both conditions predisposes men to an even greater risk for fracture than either one alone. Given the common occurrence of HH or hypogonadism in general in T2DM, a significant number of men could be at risk. To date, there is very little information on the bone health men with both hypogonadism and T2DM. Insulin resistance, which is the primary defect in T2DM, is associated with low testosterone (T) levels in men and may play a role in the bidirectional relationship between these two conditions, which together may portend a worse outcome for bone. The present manuscript aims to review the available evidences on the effect of the combination of hypogonadism and T2DM on bone health and metabolic profile, highlights the possible metabolic role of the skeleton, and examines the pathways involved in the interplay between bone, insulin resistance, and gonadal steroids.

Establishing normal values of total testosterone in adult healthy men by the use of four immunometric methods and liquid chromatography-mass spectrometry

BACKGROUND

The total testosterone (T) cutoffs clinically adopted to define late-onset hypogonadism (LOH) do not consider the differences that exist between different analytical platforms, nor do they consider the body mass index (BMI) or age of the patient. We aimed at providing method, age and BMI-specific normal values for total T in European healthy men.

METHODS

A total of 351 eugonadal healthy men were recruited, and total T was measured with four automated immunometric assays (IMAs): ARCHITECT i1000SR (Abbott), UniCel DxI800 (Beckman Coulter), Cobas e601 (Roche), IMMULITE 2000 (Siemens) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Reference ranges (RRs) were calculated for each method.

RESULTS

Passing and Bablok regression analysis and Bland-Altman plot showed an acceptable agreement between Abbott and LC-MS/MS, but a poor one between LC-MS/MS and the other IMAs. Age-specific T concentrations in non-obese (BMI <29.9 kg/m2) men were greater than in all men. The total T normal range, in non-obese men aged 18-39 years, measured with LC-MS/MS was 9.038-41.310 nmol/L. RRs calculated with LC-MS/MS statistically differed from the ones calculated with all individual IMAs, except Abbott and among all IMAs. Statistically significant differences for both upper and lower reference limits between our RRs and the ones provided by the manufacturers were also noticed.

CONCLUSIONS

We calculated normal ranges in a non-obese cohort of European men, aged 18-39 years, with four commercially available IMAs and LC-MS/MS and found statistically significant differences according to the analytical method used. Method-specific reference values can increase the accuracy of LOH diagnosis and should be standardly used.

Angiotensin blockade attenuates diabetic nephropathy in hypogonadal adult male rats

This study examined the effect of the aromatase inhibitor letrozole (0.5 mg/kg) alone or in combination with the angiotensin-receptor blocker valsartan (30 mg/kg) against streptozocin-induced diabetic nephropathy (DN) in hypogonadal (HG) rats for 12 weeks. First, we tested the HG effect on hormone levels, inflammatory cytokines, and oxidative stress in nondiabetic (ND) and diabetic (D) rats. HG was induced with the luteinizing hormone-releasing hormone antagonist cetrorelix (0.71 mg/kg). Diabetes enhanced hormonal hypogonadism and increased inflammation and oxidative stress. Next, experiments examined the effect of early letrozole and valsartan intervention on DN in HG rats. HG-ND and HG-D rats were treated with letrozole alone or in combination with valsartan. HG-D rats developed proteinuria and had increased blood urea nitrogen and creatinine, and histopathological evidence of renal injury, including glomerular hypertrophy and mesangial expansion. Valsartan alone or in combination with letrozole reduced proteinuria, improved renal functions, and reduced diabetes-induced renal angiotensin II. Both agents ameliorated nuclear factor kappa light chain enhancer of activated B cells, interleukin 1β, interleukin 6, and tumor necrosis factor alpha levels. The combination decreased superoxide dismutase, malondialdehyde, and glutathione peroxidase levels, and prevented glomerular hypertrophy. In HG-D rats, valsartan reduced renal collagen IV and transforming growth factor-beta 1, especially when the testosterone level was corrected by letrozole. Thus, normalizing testosterone and inhibiting renal angiotensin II have a renoprotective effect against DN in HG male rats.

Trials of testosterone replacement reporting cardiovascular adverse events

The numbers of testosterone prescriptions written have increased several-fold worldwide, but the incidence of pathological hypogonadism due to hypothalamic, pituitary, and testicular disease has remained unchanged. Most of these prescriptions are being dispensed to middle-aged and older men who have experienced age-related decline in serum testosterone levels; a subset of the population in which benefits of testosterone replacement is at best, modest. Recently, some randomized controlled trials have reported increased cardiovascular events in men (mainly older men and those with prevalent cardiovascular disease) with testosterone use, and a few recent meta-analyses have confirmed these findings. In this review, we discuss trials of testosterone therapy that have reported higher cardiovascular events, relevant trials that have not reported increased cardiovascular events and large trials that have focused on cardiovascular risk (mainly atherosclerosis progression) as their main outcome. We also review findings from meta-analyses that have evaluated cardiovascular events in various testosterone trials. Finally, we discuss some potential mechanisms by which testosterone use might result in an increased cardiovascular risk. As none of the trials conducted to date were adequately powered to evaluate cardiovascular events, no firm conclusions can be drawn regarding the cardiovascular safety of testosterone therapy at this time. In the interim, we hope that this review will help practitioners make informed decisions regarding the care of their patients.

Greater physical activity and higher androgen concentrations are independently associated with lower cardiometabolic risk in men

CONTEXT

Male ageing is associated with lower circulating testosterone (T) and increased incidence of cardiovascular disease (CVD). Whether physical activity (PA) interacts with hormones to modify CVD risk is unclear.

OBJECTIVE

We assessed whether PA and sex hormone concentrations were independently associated with measures of CVD risk.

PARTICIPANTS

A total of 1649 men.

METHODS

Leisure, home, work and total PA were ascertained. At baseline, serum T, dihydrotestosterone (DHT) and oestradiol (E2) were assayed. Men were stratified into high PA+high hormone (H/H); low PA+high hormone (L/H); high PA+low hormone (H/L); and low PA+low hormone (L/L).

RESULTS

Mean age was 49.8 years at outset with 415 CVD events and 127 CVD deaths occurring during 20-year follow-up. Men with higher PA and higher T or DHT had lower odds of metabolic syndrome (eg leisure H/H vs L/L odds ratio [OR] 0.17 P<.001 for T, 0.26 P<.001 for DHT). Men with higher PA and E2 had lower risk of metabolic syndrome (eg leisure PA H/H vs L/L OR 0.51, P=.001). Men with higher leisure, work or total PA and higher DHT had the lowest risk of CVD death (eg leisure H/H hazard ratio [HR] 0.55 vs L/L, P=.033). Men with lower leisure, home or work PA and higher E2 were at greater risk of CVD death (eg leisure L/H HR 1.60 vs L/L, P=.039).

CONCLUSIONS

Considering T, DHT and E2 in the context of PA better informs consideration of cardiovascular risk. A 2×2 factorial RCT assessing PA and androgens would illuminate the scope for preventing CVD in men.

Testosterone Propionate Exacerbates the Deficits of Nigrostriatal Dopaminergic System and Downregulates Nrf2 Expression in Reserpine-Treated Aged Male Rats

There is a controversy over the effects of testosterone supplements on dopaminergic function. Both neuroprotective and toxic effects of testosterone supplements are reported. The status of oxidative stress seems to explain the neuroprotective or toxic properties of testosterone. To determine the efficacy of testosterone supplements in different status of oxidative stress, the present studies analyzed the dopamine (DA)-related behaviors and neurochemical indices, as well as markers of nigrostriatal dopaminergic (NSDA) system in reserpine-treated aged male rats followed by testosterone propionate (TP) supplements. The status of oxidative stress of experimental animals was evaluated by analyzing oxidative stress parameters and nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) signaling pathway in substantia nigra (SN). Consistent with our previous studies, TP supplements to 21-month old aged male rats had the beneficial effects on NSDA system and DA-related behaviors and enhanced the antioxidative capabilities in SN. However, the beneficial effects of TP supplements on NSDA system and DA-related behaviors in aged male rats were reversed by reserpine pretreatment to them. Reserpine treatment induced the severe oxidative stress and reduced the expressions of Nrf2, heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase-1 (NQO1) in the SN of aged male rats. The TP supplements to reserpine-pretreated aged male rats exacerbated the defects in NSDA system and DA-related behaviors, aggravated oxidative damages and downregulated the expression of Nrf2, HO-1 and NQO1 in the SN. These results suggested that the efficacy of TP supplements on impaired NSDA system was related to the status of oxidative stress in experimental rats.

Serum Testosterone Concentrations and Urinary Bisphenol A, Benzophenone-3, Triclosan, and Paraben Levels in Male and Female Children and Adolescents: NHANES 2011-2012

BACKGROUND

Exposure to environmental phenols (e.g., bisphenol A, benzophenone-3, and triclosan) and parabens is widespread in the population. Many of these chemicals have been shown to have anti-androgenic effects both in vitro and in vivo.

OBJECTIVE

We examined the association of bisphenol A (BPA), benzophenone-3 (BP-3), triclosan (TCS), and parabens with serum total testosterone (TT) levels in child and adolescent participants (ages 6-19 years) in the National Health and Nutrition Examination Survey (NHANES) 2011-2012.

METHODS

We performed multivariable linear regression to estimate associations between natural log-transformed serum TT and quartiles of urinary BPA, BP-3, TCS, and parabens in male and female children (ages 6-11 years) and adolescents (ages 12-19 years).

RESULTS

BP-3 and BPA were associated with significantly lower TT in male adolescents, and BPA was associated with significantly higher TT in female adolescents. TT was not consistently associated with TCS or total parabens in children or adolescents of either sex.

CONCLUSIONS

To our knowledge, this is the first study to report an association of both BP-3 and BPA with serum TT in adolescents. Associations between BPA and TT differed according to sex in adolescents, with inverse associations in boys and positive associations in girls. BP-3 was associated with significantly lower TT in adolescent boys only. However, because of the limitations inherent to the cross-sectional study design, further studies are needed to confirm and elucidate on our findings. Citation: Scinicariello F, Buser MC. 2016. Serum testosterone concentrations and urinary bisphenol A, benzophenone-3, triclosan, and paraben levels in male and female children and adolescents: NHANES 2011-2012. Environ Health Perspect 124:1898-1904; http://dx.doi.org/10.1289/EHP150.

Effects of long-term androgen replacement therapy on the physical and mental statuses of aging males with late-onset hypogonadism: a multicenter randomized controlled trial in Japan (EARTH Study)

Androgen replacement therapy (ART) efficacy on late-onset hypogonadism (LOH) has been widely investigated in Western countries; however, it remains controversial whether ART can improve health and prolong active lifestyles. We prospectively assessed long-term ART effects on the physical and mental statuses of aging men with LOH in Japan. The primary endpoint was health-related quality of life assessed by questionnaires. Secondary endpoints included glycemic control, lipid parameters, blood pressure, waist circumference, body composition, muscular strength, International Prostate Symptom Scores (IPSS), International Index of Erectile Function-5 (IIEF-5) scores, and serum prostate-specific antigen levels. Of the 1637 eligible volunteers, 334 patients > 40 years with LOH were randomly assigned to either the ART (n = 169) or control groups (n = 165). Fifty-two weeks after the initial treatment, ART significantly affected the role physical subdomain of the short form-36 health survey (SF-36) scale (P = 0.0318). ART was also associated with significant decreases in waist circumstance (P = 0.002) and serum triglyceride (TG) (P = 0.013) and with significant increases in whole-body and leg muscle mass volumes (P = 0.071 and 0.0108, respectively), serum hemoglobin (P < 0.001), IPSS voiding subscore (P = 0.0418), and the second question on IIEF-5 (P = 0.0049). There was no significant difference between the groups in terms of severe adverse events. In conclusion, in patients with LOH, long-term ART exerted beneficial effects on Role Physical subdomain of the SF-36 scale, serum TG, waist circumstance, muscle mass volume, voiding subscore of IPSS, and the second question of IIEF-5. We hope our study will contribute to the future development of this area.

Issues Surrounding Testosterone Replacement Therapy

Testosterone is derived from Leydig cells and exerts its effects on androgen receptors to influence growth, mood, voice, and several other bodily functions. As men age, their testosterone levels decline. Human immunodeficiency virus (HIV) infection has also been associated with lowered serum testosterone levels. Subtherapeutic levels of testosterone may lead to fatigue, loss of libido, and dysphoria. Exogenous replacement of testosterone can be accomplished by several modalities (oral, topical, injection), with each having distinct advantages and disadvantages. Even though testosterone replacement has become a popular medical intervention, recent reports have made the practice increasingly controversial. Several small retrospective investigations have recently associated testosterone replacement with an increased risk of cardiovascular complications. Replacement should be used sparingly until further conclusive data regarding the efficacy and safety of testosterone become available.

Testosterone Treatment and Sexual Function in Older Men With Low Testosterone Levels

CONTEXT

The Testosterone Trials are a coordinated set of seven trials to determine the efficacy of T in symptomatic men ≥65 years old with unequivocally low T levels. Initial results of the Sexual Function Trial showed that T improved sexual activity, sexual desire, and erectile function.

OBJECTIVE

To assess the responsiveness of specific sexual activities to T treatment; to relate hormone changes to changes in sexual function; and to determine predictive baseline characteristics and T threshold for sexual outcomes.

DESIGN

A placebo-controlled trial.

SETTING

Twelve academic medical centers in the United States.

PARTICIPANTS

A total of 470 men ≥65 years of age with low libido, average T <275 ng/dL, and a partner willing to have sexual intercourse at least twice a month.

METHODS

Men were assigned to take T gel or placebo for 1 year. Sexual function was assessed by three questionnaires every 3 months: the Psychosexual Daily Questionnaire, the Derogatis Interview for Sexual Function, and the International Index of Erectile Function.

RESULTS

Compared with placebo, T administration significantly improved 10 of 12 measures of sexual activity. Incremental increases in total and free T and estradiol levels were associated with improvements in sexual activity and desire, but not erectile function. No threshold T level was observed for any outcome, and none of the 27 baseline characteristics predicted responsiveness to T.

CONCLUSIONS

In older men with low libido and low T levels, improvements in sexual desire and activity in response to T treatment were related to the magnitude of increases in T and estradiol levels, but there was no clear evidence of a threshold effect.

Testosterone replacement attenuates cognitive decline in testosterone-deprived lean rats, but not in obese rats, by mitigating brain oxidative stress

Testosterone replacement improves metabolic parameters and cognitive function in hypogonadism. However, the effects of testosterone therapy on cognition in obese condition with testosterone deprivation have not been investigated. We hypothesized that testosterone replacement improves cognitive function in testosterone-deprived obese rats by restoring brain insulin sensitivity, brain mitochondrial function, and hippocampal synaptic plasticity. Thirty male Wistar rats had either a bilateral orchiectomy (ORX: O, n = 24) or a sham operation (S, n = 6). ORX rats were further divided into two groups fed with either a normal diet (NDO) or a high-fat diet (HFO) for 12 weeks. Then, ORX rats in each dietary group were divided into two subgroups (n = 6/subgroup) and were given either castor oil or testosterone (2 mg/kg/day, s.c.) for 4 weeks. At the end of this protocol, cognitive function, metabolic parameters, brain insulin sensitivity, hippocampal synaptic plasticity, and brain mitochondrial function were determined. We found that testosterone replacement increased peripheral insulin sensitivity, decreased circulation and brain oxidative stress levels, and attenuated brain mitochondrial ROS production in HFO rats. However, testosterone failed to restore hippocampal synaptic plasticity and cognitive function in HFO rats. In contrast, in NDO rats, testosterone decreased circulation and brain oxidative stress levels, attenuated brain mitochondrial ROS production, and restored hippocampal synaptic plasticity as well as cognitive function. These findings suggest that testosterone replacement improved peripheral insulin sensitivity and decreased oxidative stress levels, but failed to restore hippocampal synaptic plasticity and cognitive function in testosterone-deprived obese rats. However, it provided beneficial effects in reversing cognitive impairment in testosterone-deprived non-obese rats.

A review of the relationships between endogenous sex steroids and incident ischemic stroke and coronary heart disease events

For decades, it has been recognized that men have a higher age-adjusted risk of ischemic cardiovascular (CVD) events compared to women, thus generating hypotheses that sex steroids contribute to CVD risk. Potential mechanisms include genomic and non-genomic effects of sex steroids as well as mediation through classic CVD risk factors and obesity. However, results from randomized studies suggest that sex steroid supplementation in men and women do not result in improved CVD outcomes and may increase CVD risk. In contrast, prospective observations from endogenous sex steroid studies, i.e. among participants not using sex steroids, have suggested the opposite relationship. We reviewed the findings of prospective observational studies in men (17 studies) and women (8 studies) that examined endogenous sex steroids and CVD risk. These studies suggested a lack of association or that lower levels of testosterone or dihydrotestosterone are associated with higher CVD risk in both men and women. Higher, rather than lower, estradiol levels were associated with higher CVD risk in women. There were several significant gaps in the literature. First, it is unclear whether more sensitive measures of sex steroid levels might detect significant differences. Second, there are few prospective studies in women. Similarly, no studies report outcomes for high-risk groups such as African-Americans and Hispanics. Finally, few studies report upon ischemic coronary disease as opposed to ischemic stroke separately, although relationships between sex steroids and CVD may vary by vascular bed. Future investigations need to examine high risk groups and to distinguish between subtypes of CVD.

Testosterone deficiency, insulin-resistant obesity and cognitive function

Testosterone is an androgenic steroid hormone, which plays an important role in the regulation of male reproduction and behaviors, as well as in the maintenance of insulin sensitivity. Several studies showed that testosterone exerted beneficial effects in brain function, including preventing neuronal cell death, balancing brain oxidative stress and antioxidant activity, improving synaptic plasticity and involving cognitive formation. Although previous studies showed that testosterone deficiency is positively correlated with cognitive impairment and insulin-resistant obesity, several studies demonstrated contradictory findings. Thus, this review comprehensively summarizes the current evidence from in vitro, in vivo and clinical studies of the relationship between testosterone deficiency and insulin-resistant obesity as well as the correlation between either insulin-resistant obesity or testosterone deficiency and cognitive impairment. Controversial reports and the mechanistic insights regarding the roles of testosterone in insulin-resistant obesity and cognitive function are also presented and discussed.

Andropause - state of the art 2015 and review of selected aspects

The term ‘male menopause’ was first used in 1944 to describe various complaints of ageing men which at least partially mirrored the climacteric symptoms in women. Continuous research resulted in the evolution of opinions about the nature of these complaints, from the clinical syndrome, diagnosed with the use of disease-targeted questionnaires, to a well-defined clinical and biochemical syndrome. The pathophysiological causes – gonad ageing (with a compensatory rise in luteinizing hormone), age-related increase in serum sex hormone-binding globulin (SHBG) levels, the role of visceral adipose tissue as a place for aromatization of androgen to estrogen, and lower sensitivity of testosterone receptors – have been described. However, no consensus was reached as far as the definition, incidence, treatment, and especially testosterone therapy, are concerned. Our review presents the current standpoints, indicating the predictive role of late-onset hypogonadism (LOH) in evaluating male health as well as the current literature reports on the risks and benefits of using testosterone therapy.

Clinical practice patterns in the assessment and management of low testosterone in men: an international survey of endocrinologists

OBJECTIVE

To document current practices in the approach to low testosterone in older men. Given that recommendations are based on low-level evidence, we hypothesized that there would be a wide variability in clinical practice patterns.

DESIGN

Members of all major endocrine and andrological societies were invited to participate in a Web-based survey of the diagnostic work-up and management of a hypothetical index case of a 61-year old overweight man presenting with symptoms suggestive of androgen deficiency, without evidence of hypothalamic-pituitary-gonadal (HPT) axis disease.

RESULTS

Nine hundred and forty-three respondents (91·2% adult endocrinologists) from Northern America (63·7%), Europe (12·7%), Oceania (8·2%), Latin America and Caribbean (7·6%), and the Middle East, Asia, or Africa (7·8%) completed the survey. Response rates among participating societies ranged from 4·1-20·0%. There was a wide variability in clinical practice patterns, especially regarding biochemical diagnosis of androgen deficiency, exclusion of HPT axis pathology, and monitoring for prostate cancer. In a man with suggestive symptoms, 42·4% of participants would offer testosterone treatment below a serum total testosterone of 10·4 nmol/l (300 ng/dl). A total of 46·0% of participants were, over the last five years, 'less inclined' to prescribe testosterone to men with nonspecific symptoms and borderline testosterone levels, compared to 'no change' (29·3%) or 'more inclined' (24·7%), P < 0·001.

CONCLUSIONS

This large-scale international survey shows a wide variability in the management of lowered testosterone in older men, with deviations from current clinical practice guidelines, and a temporal trend towards increasing reluctance to prescribe testosterone to men without classical hypogonadism. These findings highlight the need for better evidence to guide clinicians regarding testosterone therapy.

Endothelial dysfunction, insulin resistance and inflammation in congenital hypogonadism, and the effect of testosterone replacement

Patients with hypogonadism have poor cardiovascular and metabolic outcomes, and the effect of testosterone replacement therapy (TRT) is not clear. We investigated the presence of inflammation, insulin resistance and endothelial dysfunction in an unconfounded population of congenital hypogonadotrophic hypogonadism (CHH) and the effect of TRT on these subjects. A total of 60 patients with CHH (mean age 21.82±2.22 years) and 70 healthy control subjects (mean age 21.32±1.13 years) were enrolled. The demographic parameters, Asymmetric dimethylarginine (ADMA), TNF-like weak inducer of apoptosis (TWEAK), high sensitive C reactive protein (hs-CRP) and homeostatic model assessment of insulin resistance (HOMA-IR) levels were measured before and after TRT. The patients had higher Waist Circumferences (WC) (p=0.009), Diastolic Blood Pressures (p=0.02), Triglycerides (p=0.03), ADMA, insulin and HOMA-IR levels (p<0.001 for all) and lower TWEAK levels (p<0.001), compared to the healthy controls. After 5.56 ± 2.04 months of TRT, the patients had significantly elevated systolic blood pressures (p=0.01), body mass indexes and WC (p<0.001 and p=0.001 respectively) and decreased total and HDL cholesterol levels (p=0.032 and p<0.001 respectively). ADMA levels significantly increased (p=0.003), while the alterations in TWEAK, hsCRP and HOMA-IR were not significant. The results of the present study show that endothelial dysfunction, inflammation and insulin resistance are prevalent even in the very young subjects with CHH, who have no metabolic or cardiac problems at present. This increased cardiometabolic risk however, do not improve but even get worse after six months of TRT. Long term follow-up studies are warranted to investigate the unfavorable cardiometabolic effects of TRT.

Oxidative stress, testosterone, and cognition among Caucasian and Mexican-American men with and without Alzheimer's disease

BACKGROUND

The use of testosterone among aging men has been increasing, but results from studies addressing the effectiveness of testosterone replacement therapy have been equivocal.

OBJECTIVE

Given our prior pre-clinical studies that reported a major influence of oxidative stress on testosterone's neuroprotective effects, we investigated whether the negative effects of testosterone on brain function were predicted by oxidative load.

METHODS

In order to test our hypothesis, we determined whether circulating total testosterone and luteinizing hormone correlated with cognition in a subset of the Texas Alzheimer's Research & Care Consortium (TARCC) cohort, consisting of Caucasian (n = 116) and Mexican-American (n = 117) men. We also assessed whether oxidative stress (as indexed by homocysteine levels) modified this relationship between sex hormones and cognition, and whether the levels of two antioxidants, superoxide dismutase-1 and glutathione S-transferase (GST), varied as a function of circulating testosterone.

RESULTS

In a low oxidative stress environment, testosterone was positively associated with the level of the antioxidant, GST, while no deleterious effects on cognitive function were noted. In contrast, under conditions of high oxidative stress (homocysteine levels >12 μmol/L), testosterone and luteinizing hormone were associated with cognitive impairment, but only among Caucasians. The ethnic difference was attributed to significantly higher GST levels among Mexican-Americans.

CONCLUSION

While testosterone may be beneficial under conditions of low oxidative stress, testosterone appears to have negative consequences under conditions of elevated oxidative stress, but only in Caucasians. Mexican-Americans, however, were protected from any deleterious effects of testosterone, potentially due to higher levels of endogenous antioxidant defenses such as GST.

Erectile dysfunction is associated with low total serum testosterone levels and impaired flow-mediated vasodilation in intermediate risk men according to the Framingham risk score

BACKGROUND

The role erectile dysfunction (ED) coupled with low testosterone levels as early markers of atherosclerosis is not well understood.

OBJECTIVES

To analyze the relationship between serum testosterone levels with both ED and brachial artery flow-mediated vasodilation (FMD), in a primary prevention sample of men.

METHODS

We enrolled 802 asymptomatic, intermediate CV risk patients, according to the Framingham Risk Score, aged 40-80 years, who underwent the ultrasound examination of FMD, the evaluation of ED and the assessment of total serum testosterone levels.

RESULTS

Testosterone levels correlated both with FMD (r = 0.85; p < 0.0001) and IIEF-5 score (rs = 0.65; p < 0.0001). Multivariable logistic regression analyses revealed that lower serum testosterone levels were strongly associated (p < 0.001) with severe (OR 0.78; 95% CI: 0.62-0.86), and moderate ED (OR 0.85; 95% CI: 0.72-0.97), while impaired FMD percentages were strongly associated (p < 0.001) with severe (OR 0.68; 95% CI: 0.59-0.79), moderate (OR 0.76; 95% CI: 0.63-0.83) and mild to moderate ED (OR 0.8; 95% CI: 0.69-0.94). Mild ED resulted statistically associated with lower FMD (OR 0.94; 95% CI: 0.82 - 1.07; p = 0.03) but not with serum testosterone levels. These relations were not substantially affected by adjustments for further potential confounders including smoking status, hypertension, diabetes mellitus and body mass index.

CONCLUSIONS

lower total serum testosterone levels are associated with impaired FMD and ED in this sample of intermediate CV risk men according to the Framingham Risk Score.

Late-onset hypogonadism: current concepts and controversies of pathogenesis, diagnosis and treatment

Although suppressed serum testosterone (T) is common in ageing men, only a small proportion of them develop the genuine syndrome of low T associated with diffuse sexual (e.g., erectile dysfunction), physical (e.g. loss of vigor and frailty) and psychological (e.g., depression) symptoms. This syndrome carries many names, including male menopause or climacterium, andropause and partial androgen deficiency of the ageing male (PADAM). Late-onset hypogonadism (LOH) describes it best and is therefore generally preferred. The decrease of T in LOH is often marginal, and hypogonadism can be either due to primary testicular failure (low T, high luteinizing hormone (LH)) or secondary to a hypothalamic-pituitary failure (low T, low or inappropriately normal LH). The latter form is more common and it is usually associated with overweight/obesity or chronic diseases (e.g., type 2 diabetes mellitus, the metabolic syndrome, cardiovascular and chronic obstructive pulmonary disease, and frailty). A problem with the diagnosis of LOH is that often the symptoms (in 20%–40% of unselected men) and low circulating T (in 20% of men >70 years of age) do not coincide in the same individual. The European Male Ageing Study (EMAS) has recently defined the strict diagnostic criteria for LOH to include the simultaneous presence of reproducibly low serum T (total T <11 nmol l⁻¹ and free T <220 pmol l⁻¹) and three sexual symptoms (erectile dysfunction, and reduced frequency of sexual thoughts and morning erections). By these criteria, only 2% of 40- to 80-year-old men have LOH. In particular obesity, but also impaired general health, are more common causes of low T than chronological age per se. Evidence-based information whether, and how, LOH should be treated is sparse. The most logical approach is lifestyle modification, weight reduction and good treatment of comorbid diseases. T replacement is widely used for the treatment, but evidence-based information about its real benefits and short- and long-term risks, is not yet available. In this review, we will summarize the current concepts and controversies in the pathogenesis, diagnosis and treatment of LOH.

Diagnosis and Treatment of Low Testosterone among Patients with End-Stage Renal Disease

The prevalence of low testosterone level is particularly high among patients with end-stage renal disease (ESRD) and has been associated with mortality. In populations without ESRD, low testosterone level has also been associated with a number of morbidities including cardiovascular disease, diabetes mellitus, low muscle mass, low bone mass, low physical performance, and frailty. However, there is controversy regarding what constitutes low testosterone level in the aging population and at what level replacement therapy with testosterone is indicated. There are no randomized controlled trials investigating long-term outcomes of testosterone replacement therapy in populations with or without ESRD. Available trial results suggest equivocal improvements in sexual function. Muscle mass and bone mineral density appear to improve, but results in physical function and performance are mixed and there are no data on fracture prevention. Some recent data suggest harm when testosterone was given to men with limited mobility. Finally, there is little evidence that testosterone adds to existing erythropoietin agents in the treatment of anemia in ESRD. Due to lack of evidence supporting long-term use of testosterone, the authors recommend against the routine use of testosterone in ESRD patients with low testosterone levels. Testosterone treatment can be considered in those with low bone mass and total testosterone level <200 ng/dl, or in younger patients with sexual complaints with total testosterone level lower than the reference range. It is important to engage patients in discussion of risks and benefits before initiating testosterone therapy; testosterone therapy should be discontinued if the intended treatment effect is not observed after short-term use.

Protective effects of testosterone on presynaptic terminals against oligomeric β-amyloid peptide in primary culture of hippocampal neurons

Increasing lines of evidence support that testosterone may have neuroprotective effects. While observational studies reported an association between higher bioavailable testosterone or brain testosterone levels and reduced risk of Alzheimer's disease (AD), there is limited understanding of the underlying neuroprotective mechanisms. Previous studies demonstrated that testosterone could alleviate neurotoxicity induced by β-amyloid (Aβ), but these findings mainly focused on neuronal apoptosis. Since synaptic dysfunction and degeneration are early events during the pathogenesis of AD, we aim to investigate the effects of testosterone on oligomeric Aβ-induced synaptic changes. Our data suggested that exposure of primary cultured hippocampal neurons to oligomeric Aβ could reduce the length of neurites and decrease the expression of presynaptic proteins including synaptophysin, synaptotagmin, and synapsin-1. Aβ also disrupted synaptic vesicle recycling and protein folding machinery. Testosterone preserved the integrity of neurites and the expression of presynaptic proteins. It also attenuated Aβ-induced impairment of synaptic exocytosis. By using letrozole as an aromatase antagonist, we further demonstrated that the effects of testosterone on exocytosis were unlikely to be mediated through the estrogen receptor pathway. Furthermore, we showed that testosterone could attenuate Aβ-induced reduction of HSP70, which suggests a novel mechanism that links testosterone and its protective function on Aβ-induced synaptic damage. Taken together, our data provide further evidence on the beneficial effects of testosterone, which may be useful for future drug development for AD.

Testosterone therapy in older men with late-onset hypogonadism: a counter-rationale

OBJECTIVE

The past decade has seen a surge in referrals of older men for consideration of testosterone therapy for late-onset hypogonadism (LOH) to treat symptoms such as fatigue, sexual dysfunction and decreased vitality. Prescription sales of testosterone have accordingly increased by 20-fold over the same period, due mainly to marketing campaign as well as to the failure of clinicians to distinguish organic hypogonadism from LOH. This review seeks to provide a counter-rationale for testosterone therapy in LOH.

METHODS

A retrospective review of English-language epidemiologic studies, clinical trials and their relevant cited studies related to testosterone and older men was carried out.

RESULTS

Shortcomings of population studies on LOH include use of multiple numeric definitions and non-standard testosterone assays, and measurement of testosterone at a single time point. In contrast to higher estimates of prevalence based solely on numeric values, the syndromic prevalence of LOH is only 2%. Although attrition of testicular Leydig cells and slowing of gonadotropin-releasing hormone neurons both contribute to LOH, obesity and other comorbidities strongly influence testosterone levels, suggesting that testosterone is a biomarker of health. Testosterone therapy in LOH has consistently resulted in improvements in muscle mass and strength, although data regarding effects on physical function and improvements in fall and fracture rates remain unknown. Eythrocytosis is the most common adverse effect of testosterone therapy in older men, while long-term risks in the prostate and cardiovascular system remain unclear.

CONCLUSION

Considering the paucity of data on clinically meaningful outcomes, the number of uncertain risks, and the fact that modifiable risk factors adversely influence testosterone levels, healthy lifestyle and treatment of comorbidities might attenuate age-related declines in testosterone levels.

Andropause or male menopause? Rationale for testosterone replacement therapy in older men with low testosterone levels

OBJECTIVE

To provide rationale for testosterone replacement therapy (TRT) in older men with low testosterone levels and symptoms consistent with testosterone deficiency.

METHODS

The relevant literature was reviewed using PubMed.

RESULTS

Cross-sectional and longitudinal population-based studies indicate that total and free testosterone levels fall with aging, and they may be accompanied by symptoms consistent with androgen deficiency. Testosterone treatment of younger men with very low testosterone levels and hypothalamic, pituitary, or testicular disease is associated with improvements in symptoms, body composition, bone density, and hematocrit/hemoglobin. Studies evaluating testosterone treatment of older men with low testosterone levels are limited, but they suggest some increase in fat free mass, some decrease in fat mass, and some increase in bone density of the lumbar spine and femoral neck.

CONCLUSION

The Testosterone Trial should provide definitive information regarding the potential benefits of TRT in men ≥65 years of age. If efficacy is confirmed, we will still need more information regarding the risks of TRT in older men.

Hormonal changes and their impact on cognition and mental health of ageing men

Demographic changes resulting in ageing of the world's population have major implications for health. As men grow older, circulating levels of the principal androgen or male sex hormone testosterone (T) decline, while the prevalence of ill-health increases. Observational studies in middle-aged and older men have shown associations between lower levels of T and poorer mental health in older men, including worse cognitive performance, dementia and presence of depressive symptoms. The role of T metabolites, the more potent androgen dihydrotestosterone (DHT) and the oestrogen receptor ligand estradiol (E2) in the pathophysiology of cognitive decline are unclear. Studies of men undergoing androgen deprivation therapy in the setting of prostate cancer have shown subtle detrimental effects of reduced T levels on cognitive performance. Randomised trials of T supplementation in older men have been limited in size and produced variable results, with some studies showing improvement in specific tests of cognitive function. Interventional data from trials of T therapy in men with dementia are limited. Lower levels of T have also been associated with depressive symptoms in older men. Some studies have reported an effect of T therapy to improve mood and depressive symptoms in men with low or low-normal T levels. T supplementation should be considered in men with a diagnosis of androgen deficiency. Beyond this clinical indication, further research is needed to establish the benefits of T supplementation in older men at risk of deteriorating cognition and mental health.

Gynecomastia in subjects with sexual dysfunction

PURPOSE

To analyze possible relationships between gynecomastia and clinical and biochemical parameters in a large cohort of subjects with sexual dysfunction (SD).

METHODS

A consecutive series of 4,023 men attending our Outpatient Clinic for SD was retrospectively studied.

RESULTS

After excluding Klinefelter's syndrome patients, the prevalence of gynecomastia was 3.1 %. Subjects with gynecomastia had significantly lower testosterone (T) levels; the association retained statistical significance after adjusting for age and life-style. However, only 33.3 % of subjects with gynecomastia were hypogonadal. Gynecomastia was associated with delayed puberty, history of testicular or hepatic diseases, as well as cannabis abuse. Patients with gynecomastia more frequently reported sexual complaints, such as severe erectile dysfunction [odds ratio (OR) = 2.19 (1.26-3.86), p = 0.006], lower sexual desire and intercourse frequency [OR = 1.23 (1.06-1.58) and OR = 1.84 (1.22-2.78), respectively; both p < 0.05], orgasm difficulties [OR = 0.49 (0.28-0.83), p = 0.008], delayed ejaculation and lower ejaculate volume [OR = 1.89 (1.10-3.26) and OR = 1.51 (1.23-1.86), respectively; both p < 0.05]. Gynecomastia was also positively associated with severe obesity, lower testis volume and LH, and negatively with prostate-specific antigen levels. The further adjustment for T did not affect these results, except for obesity. After introducing body mass index as a further covariate, all the associations retained statistical significance, except for delayed ejaculation and ANDROTEST score. When considering gynecomastia severity, we found a step-wise, T-independent, decrease and increase of testis volume and LH, respectively. Gynecomastia was also associated with the use of several drugs in almost 40 % of our patients.

CONCLUSION

Gynecomastia is a rare condition in subjects with SD, and could indicate a testosterone deficiency that deserves further investigation.

Testosterone is essential for skeletal muscle growth in aged mice in a heterochronic parabiosis model

As humans age, they lose both muscle mass and strength (sarcopenia). Testosterone, a circulating hormone, progressively declines in aging and is associated with loss of muscle mass and strength. The surgical joining of a young and old mouse (heterochronic parabiosis) activates Notch signaling and restores muscle regenerative potential in aged mice. We hypothesize that testosterone is at least one of the factors required for the improvement seen in muscles in old mice in heterochronic parabiosis with young mice. To test this hypothesis, we established the following heterochronic parabioses between young (Y; 5 months old) and old (O; 22-23 months old) C57BL6 male mice: (1) Y:O; (2) castrated Y:O (ØY:O); (3) castrated + testosterone-treated Y:O (ØY + T:O). A group of normal young mice received empty implants, and old mice were used as controls. Parabiotic pairings were maintained for 4 weeks prior to analysis. Serum testosterone levels were three-fold higher in young than in old mice. The ØY + T:O pairing demonstrated significantly elevated levels of serum testosterone and an improvement in gastrocnemius muscle weight, muscle ultrastructure, muscle fiber cross-sectional area, and Notch-1 expression in old mice. These changes were not present in aged mice in the ØY:O pairing. These data indicate that testosterone has a critical role in mediating the improved muscle mass and ultrastructure seen in an experimental model of heterochronic parabiosis.

Male hypogonadism

Male hypogonadism is a clinical syndrome that results from failure to produce physiological concentrations of testosterone, normal amounts of sperm, or both. Hypogonadism may arise from testicular disease (primary hypogonadism) or dysfunction of the hypothalamic-pituitary unit (secondary hypogonadism). Clinical presentations vary dependent on the time of onset of androgen deficiency, whether the defect is in testosterone production or spermatogenesis, associated genetic factors, or history of androgen therapy. The clinical diagnosis of hypogonadism is made on the basis of signs and symptoms consistent with androgen deficiency and low morning testosterone concentrations in serum on multiple occasions. Several testosterone-replacement therapies are approved for treatment and should be selected according to the patient's preference, cost, availability, and formulation-specific properties. Contraindications to testosterone-replacement therapy include prostate and breast cancers, uncontrolled congestive heart failure, severe lower-urinary-tract symptoms, and erythrocytosis. Treatment should be monitored for benefits and adverse effects.

Testosterone and glucose metabolism in men: current concepts and controversies

A wealth of observational studies show that low testosterone is associated with insulin resistance and with an increased risk of diabetes and the metabolic syndrome. Experimental studies have identified potential mechanisms by which low testosterone may lead to insulin resistance. Visceral adipose tissue is an important intermediate in this relationship. Actions of testosterone or its metabolite oestradiol on other tissues such as muscle, liver, bone or the brain, and body composition-independent effects may also play a role. However, definitive evidence from randomised controlled trials (RCTs) to clarify whether the association of low testosterone with disordered glucose metabolism is causative is currently lacking. It therefore remains possible that this association is due to reverse causation, or simply originates by association with common health and lifestyle factors. RCTs of testosterone therapy in men with or without diabetes consistently show modest metabolically favourable changes in body composition. Despite this, testosterone effects on glucose metabolism have been inconsistent. Recent evidence suggests that the hypothalamic-pituitary-testicular axis suppression in the majority of obese men with metabolic disorders is functional, and may be, at least in part, reversible with weight loss. Until further evidence is available, lifestyle measures with emphasis on weight reduction, treatment of comorbidities and optimisation of diabetic control should remain the first-line treatment in these men. Such measures, if successful, may be sufficient to normalise testosterone levels in men with metabolic disorders, who typically have only modest reductions in circulating testosterone levels.

Testosterone Deficiency Syndrome: an overview with emphasis on the diagnostic conundrum

OBJECTIVES

To review the controversial issues of the Testosterone Deficiency Syndrome (TDS) with an emphasis on the concerns about the diagnosis.

DESIGN AND METHODS

The relevant literature was reviewed with particular attention to matters related to the clinical manifestations of the syndrome, the need for biochemical assessment and questions of biological and analytical variation that have to be taken into account. Therapeutic options were also appraised.

RESULTS

There are numerous difficulties with the clinical diagnosis of TDS due to the lack of specificity and subtlety of the manifestations when the degree of deficiency is not severe. Confirmation of the clinical impression requires laboratory evaluation but the choice of assays remains an unsettled issue although there is a general consensus that both free testosterone and bioavailable testosterone best reflect the degree of androgenicity. The laboratory diagnosis enjoys a great deal of credibility among clinicians but shortcomings in the interpretation of the assays need to be reiterated and the need for close collaboration between the clinician and the clinical biochemist is important for diagnostic accuracy. Even when the clinical picture is convincing, the laboratory may produce inconclusive results. The option of a therapeutic trial should be contemplated in this situation. Treatment options should be decided between the physician and the patient considering issues of availability, tolerance, efficacy and cost.

CONCLUSIONS

TDS is a prevalent condition but a matter of persistent controversy due to the vagaries of the clinical and laboratory diagnosis. Symptomatic men with documented T deficiency deserve treatment to improve their quality of life.

The effect of aggressive rosuvastatin treatment on steroid hormone production in men with coronary artery disease

Most steroid hormones are produced from cholesterol contained in low-density lipoproteins, which is uptaken by the gonads and adrenal cortex, and used as a substrate for steroidogenesis. Theoretically, in states associated with very low-density lipoprotein (LDL) cholesterol levels, cholesterol conversion to steroid hormones may be impaired. The study included 15 men with coronary artery disease, in whom initial statin treatment had been unsuccessful and therefore was replaced with rosuvastatin (20-40 mg daily). Although in 11 patients, rosuvastatin decreased plasma LDL cholesterol levels to below 70 mg/dL, the drug only moderately reduced testosterone levels and increased gonadotropin levels, as well as insignificantly increased plasma ACTH levels. Aggressive rosuvastatin treatment did not affect plasma cortisol and dehydroepiandrosterone sulphate levels, and urine free cortisol. Our results suggest that intensive rosuvastatin treatment is associated with only small changes in adrenal and testicular steroidogenesis.

Andropause: Current concepts

Andropause or late-onset hypogonadism is a common disorder which increases in prevalence with advancing age. Diagnosis of late-onset of hypogonadism is based on presence of symptoms suggestive of testosterone deficiency - prominent among them are sexual symptoms like loss of libido, morning penile erection and erectile dysfunction; and demonstration of low testosterone levels. Adequate therapeutic modalities are currently available, but disparate results of clinical trial suggest further evaluation of complex interaction between androgen deficiency and ageing. Before initiating therapy benefits and risk should be discussed with patients and in case of poor response, alternative cause should be investigated.

Lower plasma testosterone or dihydrotestosterone, but not estradiol, is associated with symptoms of intermittent claudication in older men

OBJECTIVE

In men, testosterone (T) levels decline with age, and lower T predicts all-cause and cardiovascular mortality. However, the associations of T and its metabolites, dihydrotestosterone (DHT) and estradiol (E2), with symptomatic peripheral arterial disease remain unclear. We assessed associations of T, DHT and E2 with lower limb intermittent claudication in older men.

DESIGN

Cross-sectional study.

PARTICIPANTS

Community-dwelling men aged 70-89 years resident in Perth, Western Australia.

MEASUREMENTS

Intermittent claudication was ascertained by the Edinburgh Claudication Questionnaire. Early morning, plasma T, DHT and E2 were assayed using liquid chromatography-tandem mass spectrometry.

RESULTS

There were 268 men with intermittent claudication and 2435 without claudication or any leg pain. Men with nonspecific leg pain (n = 986) were excluded. After adjusting for age, smoking, BMI, waist/hip ratio, hypertension, dyslipidaemia, diabetes, creatinine and prevalent cardiovascular disease (CVD), higher T was associated with reduced risk of having claudication (per 1 SD increase, odds ratio [OR] = 0·80, 95% confidence interval [CI] = 0·69-0·94, P = 0·006; quartiles, Q4/Q1, OR = 0·54, 95% CI = 0·36-0·81). Higher DHT was associated with reduced risk of having claudication (per 1 SD increase, OR = 0·86, 95% CI = 0·73-1·00, P = 0·048; Q4/Q1, OR = 0·64, 95% CI = 0·43-0·95). E2 was not associated with claudication (per 1 SD increase, OR = 0·96, 95% CI = 0·83-1·11, P = 0·565; Q4/Q1, OR = 0·88, 95% CI = 0·60-1·29).

CONCLUSIONS

Lower T or DHT levels, but not E2, are associated with symptoms of intermittent claudication in older men. Reduced exposure to androgens may represent a causal factor or biomarker for symptomatic peripheral arterial disease. Further studies are needed to examine underlying mechanisms and evaluate therapeutic options in ageing men.

Actions of 17β-estradiol and testosterone in the mitochondria and their implications in aging

A decline in the mitochondrial functions and aging are two closely related processes. The presence of estrogen and androgen receptors and hormone-responsive elements in the mitochondria represents the starting point for the investigation of the effects of 17β-estradiol and testosterone on the mitochondrial functions and their relationships with aging. Both steroids trigger a complex molecular mechanism that involves crosstalk between the mitochondria, nucleus, and plasma membrane, and the cytoskeleton plays a key role in these interactions. The result of this signaling is mitochondrial protection. Therefore, the molecular components of the pathways activated by the sexual steroids could represent targets for anti-aging therapies. In this review, we discuss previous studies that describe the estrogen- and testosterone-dependent actions on the mitochondrial processes implicated in aging.

Risks and benefits of testosterone therapy in older men

In young men (defined as age<50 years) with classic hypogonadism caused by known diseases of the hypothalamus, pituitary or testes, testosterone replacement therapy induces a number of beneficial effects, for example, the development of secondary sex characteristics, improvement and maintenance of sexual function, and increases in skeletal muscle mass and BMD. Moreover, testosterone treatment in this patient population is associated with a low frequency of adverse events. Circulating testosterone levels decline progressively with age, starting in the second and third decade of life, owing to defects at all levels of the hypothalamic-pituitary-testicular axis. In cohort studies, testosterone levels are associated weakly but consistently with muscle mass, strength, physical function, anaemia, BMD and bone quality, visceral adiposity, and with the risk of diabetes mellitus, coronary artery disease, falls, fractures and mortality. However, the clinical benefits and long-term risks of testosterone therapy--especially prostate-related and cardiovascular-related adverse events--have not been adequately assessed in large, randomized clinical trials involving older men (defined as age>65 years) with androgen deficiency. Therefore, a general policy of testosterone replacement in all older men with age-related decline in testosterone levels is not justified.

Approach to the patient with hypogonadotropic hypogonadism

Hypogonadotropic hypogonadism (HH) or secondary hypogonadism is defined as a clinical syndrome that results from gonadal failure due to abnormal pituitary gonadotropin levels. HH may result from either absent or inadequate hypothalamic GnRH secretion or failure of pituitary gonadotropin secretion. Several congenital and acquired causes, including functional and organic forms, have been associated with this condition. One important aspect of the HH diagnosis is that it may reflect the presence of a tumor of the hypothalamic pituitary region or even a systemic disease. On the other hand, functional forms of HH, characterized by a transient defect in GnRH secretion, are relatively common in women, in response to significant weight loss, exercise, or stress leading to hypothalamic amenorrhea. HH is typically characterized by low circulating sexual steroids associated with low or inappropriately normal gonadotropin levels. The precise and early diagnosis of HH can prevent negative physical and psychological sequelae, preserve normal peak bone mass, and restore the fertility in affected patients.

Efficacy and safety of long-acting intramuscular testosterone undecanoate in aging men: a randomised controlled study

OBJECTIVE

To evaluate the efficacy and safety of long-acting i.m. testosterone undecanoate (TU) in Malaysian men with testosterone deficiency (TD).

PATIENTS AND METHODS

A total of 120 men, aged 40-70 years, with TD (serum total testosterone [TT] ≤ 12 nmol/L) were randomised to receive either i.m. TU (1000 mg) or placebo. In all, 58 and 56 men in the placebo and treatment arm, respectively, completed the study. Participants were seen six times in the 48-week period and the following data were collected: physical examination results, haemoglobin, haematocrit, TT, lipid profile, fasting blood glucose, sex hormone-binding globulin, liver function test, prostate- specific antigen (PSA) and adverse events.

RESULTS

The mean (sd) age of the participants was 53.4 (7.6) years. A significant increase in serum TT (P < 0.001), PSA (P = 0.010), haematocrit (P < 0.001), haemoglobin (P < 0.001) and total bilirubin (P = 0.001) were seen in the treatment arm over the 48-week period. Two men in the placebo arm and one man in the treatment arm developed myocardial infarction. Common adverse events observed in the treatment arm included itching/swelling/pain at the site of injection, flushing and acne. Overall, TU injections were well tolerated.

CONCLUSIONS

TU significantly increases serum testosterone in men with TD. PSA, haemoglobin and haematocrit were significantly elevated but were within clinically safe limits. There was no significant adverse reaction that led to the cessation of treatment.

Cholesterol and male fertility: what about orphans and adopted?

The link between cholesterol homeostasis and male fertility has been clearly suggested in patients who suffer from hyperlipidemia and metabolic syndrome. This has been confirmed by the generation of several transgenic mouse models or in animals fed with high cholesterol diet. Next to the alteration of the endocrine signaling pathways through steroid receptors (androgen and estrogen receptors); "orphan" and "adopted" nuclear receptors, such as the Liver X Receptors (LXRs), the Proliferating Peroxisomal Activated Receptors (PPARs) or the Liver Receptor Homolog-1 (LRH-1), have been involved in this cross-talk. These transcription factors show distinct expression patterns in the male genital tract, explaining the large panel of phenotypes observed in transgenic male mice and highlighting the importance of lipid homesostasis and the complexity of the molecular pathways involved. Increasing our knowledge of the roles of these nuclear receptors in male germ cell differentiation could help in proposing new approaches to either treat infertile men or define new strategies for contraception.