Testosterone replacement therapy improves insulin resistance, glycaemic control, visceral adiposity and hypercholesterolaemia in hypogonadal men with type 2 diabetes

Controversial Effects of Exogenous Testosterone on Cardiovascular Diseases

The use of testosterone (T) among men aged 40 years or older was increased more than 3 times from 0.81% in 2001 to 2.91% in 2011. Until recently, the majority of the studies did not show any increased cardiovascular (CV) risk by using T in male patients with hypogonadism. What is more, some studies had observed a protective effect of using T against CV diseases. However, in 2010, a randomized clinical trial (RCT) was intended to study the advantage of T gel in older men with limitations in mobility; the study was stopped due to unexpected high prevalence of CV adverse outcome. These findings were confirmed by 2 other studies published in November of 2013 and January of 2014. Consequently, the Food and Drug Administration (FDA) had announced in January 2014 that it will reassess the safety of those treatments. Meanwhile, the agency had not reached to a definitive conclusion that FDA-approved testosterone therapy raises the risk of stroke, heart attack, or death. A report released in the broadcast of the NBC Nightly News in September of this year that the FDA says "there's little evidence that T boosting drugs taken by millions of American men are actually effective." NBC notes that the agency also pointed out that it was not convinced that they carry serious risk either. "The condition has been marketed as low 'T', and the medications are offered to help with low sex drive and fatigue among some men," notes NBC. The European Medicines Agency EMA's Pharmacovigilance Risk Assessment Committee has also responded to the concern of potential CV adverse outcomes associated with the use of T, and they have concluded in their October meeting of this year that the use of T in men who do not produce enough T raises the risk of heart diseases. In our review, we highlighted the association between exogenous T and major adverse CV outcomes. Additionally, we focused on the interplay between exogenous T and some endocrine abnormalities such as diabetes mellitus type 2, metabolic syndrome, dyslipidemia, and obesity.

Long-Term Testosterone Therapy Improves Cardiometabolic Function and Reduces Risk of Cardiovascular Disease in Men with Hypogonadism: A Real-Life Observational Registry Study Setting Comparing Treated and Untreated (Control) Groups

Objectives:

In the absence of large, prospective, placebo-controlled studies of longer duration, substantial evidence regarding the safety and risk of testosterone (T) therapy (TTh) with regard to cardiovascular (CV) outcomes can only be gleaned from observational studies. To date, there are limited studies comparing the effects of long-term TTh in men with hypogonadism who were treated or remained untreated with T, for obvious reasons. We have established a registry to assess the long-term effectiveness and safety of T in men in a urological setting. Here, we sought to compare the effects of T on a host of parameters considered to contribute to CV risk in treated and untreated men with hypogonadism (control group).

Patients and Methods:

Observational, prospective, cumulative registry study in 656 men (age: 60.7 ± 7.2 years) with total T levels ≤12.1 nmol/L and symptoms of hypogonadism. In the treatment group, men (n = 360) received parenteral T undecanoate (TU) 1000 mg/12 weeks following an initial 6-week interval for up to 10 years. Men (n = 296) who had opted against TTh served as controls. Median follow-up in both groups was 7 years. Measurements were taken at least twice a year, and 8-year data were analyzed. Mean changes over time between the 2 groups were compared by means of a mixed-effects model for repeated measures, with a random effect for intercept and fixed effects for time, group, and their interaction. To account for baseline differences between the 2 groups, changes were adjusted for age, weight, waist circumference, fasting glucose, blood pressure, and lipids.

Results:

There were 2 deaths in the T-treated group, none was related to CV events. There were 21 deaths in the untreated (control) group, 19 of which were related to CV events. The incidence of death in 10 patient-years was 0.1145 in the control group (95% confidence interval [CI]: 0.0746-0.1756; P < .000) and 0.0092 in the T-treated group (95% CI: 0.0023-0.0368; P < .000); the estimated difference between groups was 0.0804 (95% CI: 0.0189-0.3431; P < .001). The estimated reduction in mortality for the T-group was between 66% and 92%. There were also 30 nonfatal strokes and 26 nonfatal myocardial infarctions in the control group and none in the T-treated group.

Conclusion:

Long-term TU was well tolerated with excellent adherence suggesting a high level of patient satisfaction. Mortality related to CV disease was significantly reduced in the T-group.

Is Diabetic Skeletal Fragility Associated with Microvascular Complications in Bone?

PURPOSE OF REVIEW

The objective of this literature review is to determine whether there are indications that microvascular complications occur in diabetic bone. Evidence definitively linking diabetic skeletal fragility with microvascular complications in bone remains elusive.

RECENT FINDINGS

Circumstantial evidence, some recent and some lost to time, suggests that atherosclerotic vascular diseases such as peripheral arterial disease cause poor blood perfusion of bone and subsequent hypoxia and contribute to low bone density and high cortical porosity, patterns similar to some recently observed in diabetic subjects. Evidence also exists to suggest that potentially anti-angiogenic conditions, such as impaired vascular endothelial growth factor (VEGF) signaling, predominate in diabetic bone. Microvascular complications may contribute, in part, to diabetic skeletal fragility but data supporting this interpretation are primarily circumstantial at this time. This review highlights gaps in our knowledge and hopefully spurs further discussions and research on this topic.

Effects of Elevated β-Estradiol Levels on the Functional Morphology of the Testis - New Insights

Elevated estradiol levels are correlated with male infertility. Causes of hyperestrogenism include diseases of the adrenal cortex, testis or medications affecting the hypothalamus-pituitary-gonadal axis. The aim of our study was to elucidate the effects of estradiol treatment on testicular cellular morphology and function, with reference to the treatment regimen received. Testes samples (n = 9) were obtained post-orchiectomy from male-to-female transsexuals within the age range of 26–52 years. Each patient had a minimum of 1–6 years estradiol treatment. For comparison, additional samples were obtained from microscopically unaltered testicular tissue surrounding tumors (n = 7). The tissues obtained were investigated by stereomicroscopy, histochemistry, scanning electron microscopy (SEM) and immunohistochemistry. Our studies revealed that estradiol treatment significantly decreased the diameter of the seminiferous tubules (p < 0.05) and induced fatty degeneration in the surrounding connective tissue. An increase in collagen fiber synthesis in the extracellular matrix (ECM) surrounding the seminiferous tubules was also induced. Spermatogenesis was impaired resulting in mainly spermatogonia being present. Sertoli cells revealed diminished expression of estrogen receptor alpha (ERα). Both Sertoli and Leydig cells showed morphological alterations and glycoprotein accumulations. These results demonstrate that increased estradiol levels drastically impact the human testis.

Prevalence of hypogonadism in male Type 2 diabetes mellitus patients with and without coronary artery disease

AIM

The present study is carried out to investigate hypogonadism using serum testosterone levels in male Type 2 diabetes mellitus (T2DM) subjects with and without coronary artery disease (CAD).

SUBJECTS AND METHODS

A total of 150 age and body mass index-matched male subjects in the age group of 30-70 years were recruited in three groups; Group A - subjects with normal glucose tolerance, Group B - T2DM subjects without CAD, and Group C - T2DM subjects with CAD (n = 50 each group). Subjects with CAD were diagnosed on the basis of electrocardiogram, treadmill testing, stress echocardiography, or coronary angiography. Total testosterone (TT), free testosterone (FT), bioavailable testosterone, calculated FT and glycemic parameters were measured and compared between all the three study groups. One-way ANOVA followed by post hoc Tukey's test and Pearson's coefficient of correlation tests were used for analysis.

RESULTS

Hypogonadism (TT <3 ng/ml) was observed in 40% (20/50) of subjects in Group C and 32% (16/50) of subjects in Group B as compared to only 14% (7/50) of subjects in Group A (Groups A vs. B; P = 0.055, Groups A vs. C; P = 0.006 and Groups B vs. C; P = 0.53). Group C subjects had significantly lower levels of TT (3.55 ± 1.46 ng/ml vs. 4.73 ± 2.17 ng/ml, P = 0.005), calculated FT (0.062 ± 0.0255 pg/ml vs. 0.0951 ± 0.0508 pg/ml, P ≤ 0.001), and bioavailable testosterone (1.48 ± 0.65 ng/ml vs. 2.18 ± 1.20 ng/ml, P ≤ 0.001) compared to control Group A subjects. There was no significant difference in any of the testosterone parameters between Groups A and B. Furthermore, an overall positive correlation was found between hypogonadism and CAD (r = 0.177, P = 0.030, n = 150).

CONCLUSION

We observed hypogonadism as indicated by low testosterone levels in a significant proportion of male T2DM subjects with CAD.

Role of Testosterone in the Treatment of Cardiovascular Disease

Cardiovascular disease (CVD) is the most prevalent non-communicable cause of death worldwide. Testosterone is a sex hormone that is predominant in males but also occurs in lower concentrations in females. It has effects directly on the blood vessels of the cardiovascular system and on the heart, as well as effects on risk factors for CVD. Serum testosterone concentrations are known to decrease with age and reduced testosterone levels are linked to premature coronary artery disease, unfavourable effects on CVD risk factors and increased risk of cardiovascular mortality independent of age. A significant number of men with heart failure demonstrate reduced serum testosterone concentrations and there is early evidence suggesting that low testosterone levels affect cardiac repolarisation. Any association between endogenous testosterone concentrations and CVD in women has yet to be established. Testosterone replacement is used to treat men with hypogonadism but also has cardiovascular effects. This review will present the current evidence, expert opinion and controversies around the role of testosterone in the pathophysiology of CVD and surrounding the use of testosterone treatment and its effects on the cardiovascular system and CVD.

Drivers: A Biologically Contextualized, Cross-Inferential View of the Epidemiology of Neurodegenerative Disorders

Background:

Sutherland et al. (2011) suggested that, instead of risk factors for single neurodegenerative disorders (NDDs), there was a need to identify specific “drivers”, i.e., risk factors with impact on specific deposits, such as amyloid-β, tau, or α-synuclein, acting across entities.

Objectives and Methods:

Redefining drivers as “neither protein/gene- nor entity-specific features identifiable in the clinical and general epidemiology of conformational NDDs (CNDDs) as potential footprints of templating/spread/transfer mechanisms”, we conducted an analysis of the epidemiology of ten CNDDs, searching for patterns.

Results:

We identified seven potential drivers, each of which was shared by at least two CNDDs: 1) an age-at-exposure-related susceptibility to Creutzfeldt-Jakob disease (CJD) and several late-life CNDDs; 2) a relationship between age at onset, survival, and incidence; 3) shared genetic risk factors for CJD and late-life CNNDs; 4) partly shared personal (diagnostic, educational, behavioral, and social risk factors) predating clinical onset of late-life CNDDs; 5) two environmental risk factors, namely, surgery for sporadic CJD and amyotrophic lateral sclerosis, and Bordetella pertussis infection for Parkinson’s disease; 6) reticulo-endothelial system stressors or general drivers (andropause or premenopausal estrogen deficiency, APOEɛ4, and vascular risk factors) for late-life CNDDs such as dementia/Alzheimer’s disease, type-2 diabetes mellitus, and some sporadic cardiac and vascular degenerative diseases; and 7) a high, invariant incidence ratio of sporadic to genetic forms of mid- and late-life CNDDs, and type-2 diabetes mellitus.

Conclusion:

There might be a systematic epidemiologic pattern induced by specific proteins (PrP, TDP-43, SOD1, α-synuclein, amyloid-β, tau, Langerhans islet peptide, and transthyretin) or established combinations of these.

Testosterone Deficiency Induces Changes of the Transcriptomes of Visceral Adipose Tissue in Miniature Pigs Fed a High-Fat and High-Cholesterol Diet

Testosterone deficiency causes fat deposition, particularly in visceral fat, and its replacement might reverse fat accumulation, however, the underlying mechanisms of such processes under diet-induced adiposity are largely unknown. To gain insights into the genome-wide role of androgen on visceral adipose tissue (VAT), RNA-Seq was used to investigate testosterone deficiency induced changes of VAT in miniature pigs fed a high-fat and high-cholesterol (HFC) diet among intact male pigs (IM), castrated male pigs (CM), and castrated male pigs with testosterone replacement (CMT) treatments. The results showed that testosterone deficiency significantly increased VAT deposition and serum leptin concentrations. Moreover, a total of 1732 differentially expressed genes (DEGs) were identified between any two groups. Compared with gene expression profiles in IM and CMT pigs, upregulated genes in CM pigs, i.e., LOC100520753 (CD68), LCN2, EMR1, S100A9, NCF1 (p47phox), and LEP, were mainly involved in inflammatory response, oxidation-reduction process, and lipid metabolic process, while downregulated genes in CM pigs, i.e., ABHD5, SPP1, and GAS6, were focused on cell differentiation and cell adhesion. Taken together, our study demonstrates that testosterone deficiency alters the expression of numerous genes involved in key biological processes of VAT accumulation under HFC diet and provides a novel genome-wide view on the role of androgen on VAT deposition under HFC diet, thus improving our understanding of the molecular mechanisms involved in VAT changes induced by testosterone deficiency.

Testosterone supplementation improves glucose homeostasis despite increasing hepatic insulin resistance in male mouse model of type 2 diabetes mellitus

Clinical studies have revealed that testosterone supplementation had a positive effect on glucose homeostasis in type 2 diabetes mellitus (T2DM), but did not address how testosterone supplementation affected insulin responsiveness in the liver, a key glucose homeostatic organ. In this study, we aimed to study the effect of testosterone supplementation on hepatic insulin responsiveness and glucose homeostasis through liver in male high-fat diet-induced T2DM mice. Testosterone treatment to T2DM animals showed reduced hepatic glucose output. Testosterone inhibited the insulin signaling in liver, thus increased insulin resistance. However, testosterone treatment inactivated GSK3α independent of PI3K/AKT pathway and inhibited FOXO1 By interaction of androgen receptor to FOXO1 and downregulated PEPCK, causing repression of gluconeogenic pathway, which is otherwise upregulated in T2DM, resulted in better glucose homeostasis.

Prevalence and Etiology of Hypogonadism in Young Men With Chronic Spinal Cord Injury: A Cross-Sectional Analysis From Two University-Based Rehabilitation Centers

BACKGROUND

Spinal cord injury (SCI) triggers an "accelerated aging" process that may include development of hypogonadism, even among younger men with SCI; however, few studies have investigated the prevalence or etiology of hypogonadism in men with SCI. Young men with SCI also are at increased risk for developing metabolic dysfunction after injury, which may be exacerbated by concomitant testosterone (T) deficiency, thus identifying the prevalence and risk factors for T deficiency in men with SCI is important for their long-term health.

OBJECTIVE

To investigate the prevalence, risk factors, and etiology of T deficiency (hypogonadism) in otherwise-healthy men with chronic, motor complete SCI.

DESIGN

Secondary cross-sectional analysis.

SETTING

Rehabilitation research centers in Washington, DC, and Miami, Florida.

PARTICIPANTS

Men (n = 58) aged 18-45 years with chronic (≥1 year), motor complete SCI without comorbidities or use of testosterone therapy.

METHODS

Plasma concentrations of hormones were measured with standardized assays. Body composition was assessed with dual-energy x-ray absorptiometry scan.

MAIN OUTCOME MEASUREMENTS

Serum total T and calculated free T.

RESULTS

T deficiency was more common in men after SCI than in a matched cohort of similarly-aged men without SCI (25%, SCI versus 6.7%, non-SCI, P < .001). The risk of hypogonadism appeared to be increased in men with more extensive injury and with higher percent body fat. The majority of men with SCI with low T had low serum LH levels, suggesting that central suppression of the hypothalamic-pituitary-gonadal axis may be the most common etiology of hypogonadism after SCI.

CONCLUSIONS

Hypogonadism is more common in young men with SCI than in similarly aged men without SCI, suggesting that SCI should be identified as a risk factor for T deficiency and that routine screening for hypogonadism should be performed in the SCI population.

LEVEL OF EVIDENCE

II.

Testosterone differentially regulates targets of lipid and glucose metabolism in liver, muscle and adipose tissues of the testicular feminised mouse

Testosterone deficiency is commonly associated with obesity, metabolic syndrome, type 2 diabetes and their clinical consequences-hepatic steatosis and atherosclerosis. The testicular feminised mouse (non-functional androgen receptor and low testosterone) develops fatty liver and aortic lipid streaks on a high-fat diet, whereas androgen-replete XY littermate controls do not. Testosterone treatment ameliorates these effects, although the underlying mechanisms remain unknown. We compared the influence of testosterone on the expression of regulatory targets of glucose, cholesterol and lipid metabolism in muscle, liver, abdominal subcutaneous and visceral adipose tissue. Testicular feminised mice displayed significantly reduced GLUT4 in muscle and glycolytic enzymes in muscle, liver and abdominal subcutaneous but not visceral adipose tissue. Lipoprotein lipase required for fatty acid uptake was only reduced in subcutaneous adipose tissue; enzymes of fatty acid synthesis were increased in liver and subcutaneous tissue. Stearoyl-CoA desaturase-1 that catalyses oleic acid synthesis and is associated with insulin resistance was increased in visceral adipose tissue and cholesterol efflux components (ABCA1, apoE) were decreased in subcutaneous and liver tissue. Master regulator nuclear receptors involved in metabolism-Liver X receptor expression was suppressed in all tissues except visceral adipose tissue, whereas PPARγ was lower in abdominal subcutaneous and visceral adipose tissue and PPARα only in abdominal subcutaneous. Testosterone treatment improved the expression (androgen receptor independent) of some targets but not all. These exploratory data suggest that androgen deficiency may reduce the buffering capability for glucose uptake and utilisation in abdominal subcutaneous and muscle and fatty acids in abdominal subcutaneous. This would lead to an overspill and uptake of excess glucose and triglycerides into visceral adipose tissue, liver and arterial walls.

Testosterone Replacement Therapy and Mortality in Older Men

While US testosterone prescriptions have tripled in the last decade with lower trends in Europe, debate continues over the risks, benefits and appropriate use of testosterone replacement therapy (TRT). Several authors blame advertising and the availability of more convenient formulations, whilst others have pointed out that the routine testing of men with erectile dysfunction (ED) (a significant marker of cardiovascular risk) and those with diabetes would inevitably increase the diagnosis of hypogonadism and lead to an increase in totally appropriate prescribing. They commented that this was merely an appropriate correction of previous under-diagnosis and under-treatment in line with evidence based guidelines. It is unlikely that persuasive advertising or convenient formulations could grow a market over such a sustained period if the treatment was not effective. Urologists and primary care physicians are the most frequent initiators of TRT usually for ED. Benefits are clearly established for sexual function, increase in lean muscle mass and strength, mood and cognitive function, with a possible reduction in frailty and osteoporosis. There remains no evidence that TRT is associated with increased risk of prostate cancer or symptomatic benign prostatic hyperplasia, yet the decision to initiate and continue therapy is often decided by urologists. The cardiovascular issues associated with TRT have been clarified by recent studies showing that therapy associated with clear increases in serum testosterone levels to the normal range is associated with reduced all-cause mortality. Studies reporting to show increased risk have been subject to flawed designs with inadequate baseline diagnosis and follow-up testing. Effectively, they have compared non-treated patients with under-treated or non-compliant subjects involving a range of different therapy regimes. Recent evidence suggests long-acting injections may be associated with decreased cardiovascular risk, but the transdermal route may be associated with potentially relatively greater risk because of conversion to dihydrotestosterone by the effect of 5-alpha reductase in skin. The multiple effects of TRT may add up to a considerable benefit to the patient that might be underestimated by the physician primarily concerned with his own specialty. In a response to concerns about the possible risks associated with inappropriate prescribing expressed by Public Citizen, the Food and Drug Administration (FDA) published a complete refutation of all the concerns, only to issue a subsequent bulletin of concern over inappropriate use, whilst confirming the benefits in treating men with established testosterone deficiency. No additional evidence was provided for this apparent change of opinion, but longer term safety data on testosterone products were strongly suggested. In contrast, the European Medicines Agency (EMA), in November 2014, concluded that “there is no consistent evidence of increased cardiovascular risk with testosterone products”. This paper explores the most recent evidence surrounding the benefits and risks associated with TRT.

Effect of testosterone on insulin sensitivity, oxidative metabolism and body composition in aging men with type 2 diabetes on metformin monotherapy

AIMS

To evaluate the effect of testosterone replacement therapy (TRT) on body composition, insulin sensitivity, oxidative metabolism and glycaemic control in aging men with lowered bioavailable testosterone (BioT) levels and type 2 diabetes mellitus (T2D) controlled on metformin monotherapy.

MATERIALS AND METHODS

We conducted a randomized, double-blind, placebo-controlled study in 39 men aged 50-70 years with BioT levels <7.3 nmol/L and T2D treated with metformin monotherapy. Patients were randomized to testosterone gel (TRT, n = 20) or placebo (n = 19) for 24 weeks. Lean body mass (LBM), total and regional fat mass were measured using whole-body dual-energy X-ray absorptiometry scans. Whole-body peripheral insulin sensitivity, endogenous glucose production (EGP) and substrate oxidation were assessed by euglycaemic-hyperinsulinaemic clamp with glucose tracer and combined with indirect calorimetry. Coefficients (β) represent the placebo-controlled mean effect of intervention.

RESULTS

LBM (β = 1.9 kg, p = 0.001) increased after TRT, while total fat mass (β = -1.3 kg, p = 0.009), fat mass trunk (β = -0.7 kg, p = 0.043), fat mass legs (β = -0.7 kg, p = 0.025), fat mass arms (β = -0.3 kg, p = 0.001), and HDL cholesterol (β = -0.11 mmol/L, p = 0.009) decreased after TRT compared with placebo. Insulin-stimulated glucose disposal rates did not change in response to TRT compared with placebo (p = 0.18). Moreover, glycated haemoglobin, and basal and insulin-stimulated rates of EGP, lipid- and glucose-oxidation were unaltered after TRT.

CONCLUSION

TRT in aging men with lowered BioT levels and T2D controlled on metformin monotherapy improved body composition; however, glycaemic control, peripheral insulin sensitivity, EGP and substrate metabolism were unchanged.

Testosterone undecanoate improves lipid profile in patients with type 1 diabetes and hypogonadotrophic hypogonadism

Testosterone deficiency (Td) has been associated with the metabolic syndrome. Few studies have evaluated this condition in type 1 diabetes (T1D). The primary aim of this study was to evaluate the effectiveness of testosterone undecanoate (TU) on insulin sensitivity, glycemic control, anthropometric parameters, blood pressure and lipid profile in patients with Td and T1D. We performed a randomized placebo-controlled multicenter study.

INCLUSION CRITERIA

a) age ≥ 18 years; b) autoimmune diabetes; c) Td (total testosterone <10 nmol/L or calculated free testosterone <225 pmol/L and low/normal LH; d) ability to sign informed consent; e) comply with the study protocol.

EXCLUSION CRITERIA

a) pituitary tumor, empty sella, hyperprolactinemia, panhypopituitarism or secondary hypogonadism; b) contraindications for treatment with testosterone undecanoate (TU); c) patients who did not agree to sign their informed consent. Six patients were randomly assigned to testosterone undecanoate (TU) treatment and 7 to placebo with the following dosing schedule: baseline, 6 weeks and 16 weeks. Blood test, anthropometric parameters, blood pressure and insulin sensitivity were determined at baseline, 6, 16 and 22 weeks. No differences were observed regarding insulin sensitivity, HbA_1c or basal glucose, anthropometric parameters or blood pressure. At 22 weeks, the decrease in total cholesterol was 37.4 ± 27.5 mg/dL in the TU group compared with an increase of 13.2 ± 17.8 mg/dL in the placebo group (P<0.005), and LDL cholesterol concentration decreased 30.2 ± 22.1 mg/dL, compared with an increase of 10.5 ± 13.4 mg/dL in the placebo group (P=0.004). We conclude that treatment with TU in patients with T1D and Td improves lipid profile, with no effects on metabolic control or anthropometric parameters.

Treatment of Men for “Low Testosterone”: A Systematic Review

Testosterone products are recommended by some prescribers in response to a diagnosis or presumption of “low testosterone” (low-T) for cardiovascular health, sexual function, muscle weakness or wasting, mood and behavior, and cognition. We performed a systematic review of 156 eligible randomized controlled trials in which testosterone was compared to placebo for one or more of these conditions. We included studies in bibliographic databases between January 1, 1950 and April 9, 2016, and excluded studies involving bodybuilding, contraceptive effectiveness, or treatment of any condition in women or children. Studies with multiple relevant endpoints were included in all relevant tables. Testosterone supplementation did not show consistent benefit for cardiovascular risk, sexual function, mood and behavior, or cognition. Studies that examined clinical cardiovascular endpoints have not favored testosterone therapy over placebo. Testosterone is ineffective in treating erectile dysfunction and controlled trials did not show a consistent effect on libido. Testosterone supplementation consistently increased muscle strength but did not have beneficial effects on physical function. Most studies on mood-related endpoints found no beneficial effect of testosterone treatment on personality, psychological well-being, or mood. The prescription of testosterone supplementation for low-T for cardiovascular health, sexual function, physical function, mood, or cognitive function is without support from randomized clinical trials.

Clinicopathologic assessment of hypogonadism in men with type 2 diabetes mellitus

OBJECTIVE

To determine the prevalence of hypogonadism in men with type 2 diabetes mellitus and evaluate its clinical and pathologic correlates.

SUBJECTS AND METHODS

In a cross-sectional survey of 200 type 2 diabetic males aged 32-69 years, total testosterone (TT), follicle stimulating hormone, luteinizing hormone, waist circumference (WC), glycated hemoglobin, and lipids were measured. Clinical assessment of androgen deficiency was done using the androgen deficiency in aging male (ADAM) questionnaire. Overt hypogonadism was defined as a combination of positive ADAM score and TT < 8 nmol/L while possible hypogonadism was defined as positive ADAM score with TT 8-12 nmol/L.

RESULTS

Overt and possible hypogonadism occurred in 29.5% and 23% of the participants, respectively. Majority (76.3%) of the subjects who had overt hypogonadism had the hypogonadotrophic pattern. Hypogonadal subjects were significantly older (P = 0.014) and had higher mean WC (P = 0.009) than eugonadal ones. Erectile dysfunction was the most common symptom, occurring in 79.7% of overtly hypogonadal subjects. There was a significant negative correlation between WC and serum TT (r = -0.41, P = 0.001).

CONCLUSION

There is a high frequency of symptomatic hypogonadism in men with type 2 diabetes and the frequency increases with advancing age and visceral adiposity.

Exercise for the diabetic brain: how physical training may help prevent dementia and Alzheimer's disease in T2DM patients

Epidemiological studies indicate that patients with type 2 diabetes mellitus (T2DM) are at increased risk of developing dementia/Alzheimer's disease (AD). This review, which is based on recent studies, presents a molecular framework that links the two diseases and explains how physical training could help counteract neurodegeneration in T2DM patients. Inflammatory, oxidative, and metabolic changes in T2DM patients cause cerebrovascular complications and can lead to blood-brain-barrier (BBB) breakdown. Peripherally increased pro-inflammatory molecules can then pass the BBB more easily and activate stress-activated pathways, thereby promoting key pathological features of dementia/AD such as brain insulin resistance, mitochondrial dysfunction, and accumulation of neurotoxic beta-amyloid (Aβ) oligomers, leading to synaptic loss, neuronal dysfunction, and cell death. Ceramides can also pass the BBB, induce pro-inflammatory reactions, and disturb brain insulin signaling. In a vicious circle, oxidative stress and the pro-inflammatory environment intensify, leading to further cognitive decline. Low testosterone levels might be a common risk factor in T2DM and AD. Regular physical exercise reinforces antioxidative capacity, reduces oxidative stress, and has anti-inflammatory effects. It improves endothelial function and might increase brain capillarization. Physical training can further counteract dyslipidemia and reduce increased ceramide levels. It might also improve Aβ clearance by up-regulating Aβ transporters and, in some cases, increase basal testosterone levels. In addition, regular physical activity can induce neurogenesis. Physical training should therefore be emphasized as a part of prevention programs developed for diabetic patients to minimize the risk of the onset of neurodegenerative diseases among this specific patient group.

Effects of testosterone replacement on metabolic and inflammatory markers in men with opioid-induced androgen deficiency

OBJECTIVE

Symptomatic androgen deficiency is common in patients taking opioid analgesics, and testosterone replacement in these men improves libido, quality of life and body composition. However, the effects of testosterone replacement on metabolic and inflammatory markers in this setting have not been evaluated. This is important as opiate use itself has been associated with metabolic abnormalities. The objective of this investigation was to determine the effects of testosterone administration on metabolic and inflammatory markers in adult men with opioid-induced androgen deficiency.

METHODS

Sixty-four nondiabetic men aged 18 to 64 years using opioid analgesics for chronic noncancer pain with total testosterone levels <12 nmol/l were randomized to 14 weeks of transdermal testosterone gel or placebo gel daily. Total testosterone levels were measured by liquid chromatography mass spectrometry, and free testosterone was calculated using the law-of-mass-action equation. Metabolic parameters, inflammatory markers and oral glucose tolerance test (OGTT) were evaluated at baseline and 14 weeks.

RESULTS

Baseline characteristics were similar between the two groups. Testosterone concentrations increased from 7·7 ± 3·0 to 27 ± 19 nmol/l in the testosterone group, but did not meaningfully change in placebo group. Mean changes in metabolic and inflammatory markers during intervention did not differ significantly between groups and were not related to changes in on-treatment serum testosterone concentrations. Glucose and insulin response to the 75 g OGTT also did not differ between groups.

CONCLUSION

In this 14-week trial, testosterone administration in men with opioid-induced androgen deficiency was not associated with worsening of metabolic and inflammatory markers.

Testosterone and Voluntary Exercise Promote Angiogenesis in Hearts of Rats with Diabetes by Enhancing Expression of VEGF-A and SDF-1a

OBJECTIVES

Impaired angiogenesis in cardiac tissue is a major complication of diabetes. This study was aimed to evaluate the effects of testosterone and voluntary exercise on vascular endothelial growth factor-A (VEGF-A), stromal cell-derived factor 1a (SDF-1a) and myocardial capillary density in heart of rats with diabetes.

METHODS

Type 1 diabetes was induced by intraperitoneal injection of 55 mg/kg of streptozotocin in 80 male Wistar rats. After 42 days of treatment with testosterone (2 mg/kg/day) or voluntary exercise alone or in combination, angiogenesis was determined in the hearts by immunostaining for PECAM-1/CD31. The expressions of VEGF-A and SDF-1a levels in heart were also determined by the ELISA method.

RESULTS

Our results showed that capillary density, VEGF-A and SDF-1a levels in the heart were significantly decreased in castrated rats with diabetes, whereas these effects were reversed by testosterone and exercise. Furthermore, simultaneous treatment of castrated rats with diabetes with testosterone and exercise had a synergistic effect on capillary density, VEGF-A and SDF-1a levels in the heart. In the group with diabetes, either testosterone or exercise increased capillary density, VEGF-A and SDF-1a protein levels in heart tissue. However, the effects of combination therapy in rats with diabetes with testosterone and exercise on capillary density, VEGF-A and SDF-1a levels in the heart was synergistic.

CONCLUSIONS

Our findings suggest that testosterone and exercise can promote neoangiogenesis in rats with diabetes and in castrated rats with diabetes. The proangiogenesis effect of testosterone and exercise is associated with the enhanced expression of VEGF-A and SDF-1a in heart tissue.

Low testosterone and non-alcoholic fatty liver disease: Evidence for their independent association in men with chronic spinal cord injury

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) has been claimed as a liver phenotype of metabolic syndrome, which in turn is associated with male hypogonadism. We assessed whether an independent association between NAFLD and androgen deficiency could be revealed in men with chronic spinal cord injury (SCI), who exhibit a high prevalence of biochemical androgen deficiency and a combination of risk factors for metabolic syndrome.

DESIGN

Fifty-five consecutive men with chronic SCI admitted to a rehabilitation program underwent clinical/biochemical evaluations and liver ultrasonography.

RESULTS

NAFLD was diagnosed in 27 patients (49.1%). Men with NAFLD were older and exhibited significantly higher body mass index, Homeostatic model assessment of insulin resistance, triglycerides and gamma-glutamyl transpeptidase values, lower total and free testosterone levels and they were engaged in a significantly poorer weekly leisure time physical activity (LTPA). At the multiple logistic regression analysis, only total and free testosterone levels exhibited a significant independent association with NAFLD. The risk of having NAFLD increased indeed of 1% for each decrement of 1 ng/dL of total testosterone and of 3% for each decrement of 1 pg/mL of free testosterone, after adjustment for confounders. In men with total testosterone < 300 ng/dL (36.4%) the prevalence of NAFLD reached 85%: they had a risk of having NAFLD significantly higher (∼12-fold) than those with total testosterone ≥ 300 ng/dL, after adjustment for confounders.

CONCLUSION

The evidence of an independent association between NAFLD and low testosterone is strongly reinforced by its demonstration in men with chronic SCI, in spite of the many confounders peculiar to this population.

Etiologic Framework for the Study of Neurodegenerative Disorders as Well as Vascular and Metabolic Comorbidities on the Grounds of Shared Epidemiologic and Biologic Features

Background: During the last two decades, protein aggregation at all organismal levels, from viruses to humans, has emerged from a neglected area of protein science to become a central issue in biology and biomedicine. This article constitutes a risk-based review aimed at supporting an etiologic scenario of selected, sporadic, protein-associated, i.e., conformational, neurodegenerative disorders (NDDs), and their vascular- and metabolic-associated ailments.

Methods: A rationale is adopted, to incorporate selected clinical data and results from animal-model research, complementing epidemiologic evidences reported in two prior articles.

Findings: Theory is formulated assuming an underlying conformational transmission mechanism, mediated either by horizontal transfer of mammalian genes coding for specific aggregation-prone proteins, or by xeno-templating between bacterial and host proteins. We build a few population-based and experimentally-testable hypotheses focusing on: (1) non-disposable surgical instruments for sporadic Creutzfeldt-Jakob disease (sCJD) and other rapid progressive neurodegenerative dementia (sRPNDd), multiple system atrophy (MSA), and motor neuron disease (MND); and (2) specific bacterial infections such as B. pertussis and E. coli for all forms, but particularly for late-life sporadic conformational, NDDs, type 2 diabetes mellitus (T2DM), and atherosclerosis where natural protein fibrils present in such organisms as a result of adaptation to the human host induce prion-like mechanisms.

Conclusion: Implications for cohort alignment and experimental animal research are discussed and research lines proposed.

Testosterone deficiency and cardiovascular mortality

New concerns have been raised regarding cardiovascular (CV) risks with testosterone (T) therapy (TTh). These concerns are based primarily on two widely reported retrospective studies. However, methodological flaws and data errors invalidate both studies as credible evidence of risk. One showed reduced adverse events by half in T-treated men but reversed this result using an unproven statistical approach. The authors subsequently acknowledged serious data errors including nearly 10% contamination of the dataset by women. The second study mistakenly used the rate of T prescriptions written by healthcare providers to men with recent myocardial infarction (MI) as a proxy for the naturally occurring rate of MI. Numerous studies suggest T is beneficial, including decreased mortality in association with TTh, reduced MI rate with TTh in men with the greatest MI risk prognosis, and reduced CV and overall mortality with higher serum levels of endogenous T. Randomized controlled trials have demonstrated benefits of TTh in men with coronary artery disease and congestive heart failure. Improvement in CV risk factors such as fat mass and glycemic control have been repeatedly demonstrated in T-deficient men treated with T. The current evidence does not support the belief that TTh is associated with increased CV risk or CV mortality. On the contrary, a wealth of evidence accumulated over several decades suggests that low serum T levels are associated with increased risk and that higher endogenous T, as well as TTh itself, appear to be beneficial for CV mortality and risk.

Taurine and pioglitazone attenuate diabetes-induced testicular damage by abrogation of oxidative stress and up-regulation of the pituitary–gonadal axis

Chronic hyperglycemia is associated with impairment of testicular function. The current study aimed to investigate the protective effects and the possible mechanisms of taurine and pioglitazone against diabetes-induced testicular dysfunction in rats. Diabetes was induced by streptozotocin injection. Both normal and diabetic rats received taurine (100 mg/kg) or pioglitazone (10 mg/kg) orally and daily for 6 weeks. Diabetic rats showed a significant (P < 0.001) increase in glycosylated hemoglobin, glucose, homeostasis model of insulin resistance, and pro-inflammatory cytokines. Serum insulin, testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were significantly (P < 0.001) decreased in diabetic rats. Taurine and pioglitazone alleviated hyperglycemia, decreased pro-inflammatory cytokines, and increased circulating levels of insulin, testosterone, LH, and FSH. Gene and protein expression of LH and FSH receptors and cytochrome P450 17α-hydroxylase (CYP17) was significantly (P < 0.001) down-regulated in testes of diabetic rats, an effect which was significantly increased after administration of taurine and pioglitazone. In addition, taurine and pioglitazone significantly decreased lipid peroxidation and DNA damage, and enhanced activity of the antioxidant enzymes in testes of diabetic rats. In conclusion, taurine and pioglitazone exerted protective effects against diabetes-induced testicular damage through attenuation of hyperglycemia, inflammation, oxidative stress and DNA damage, and up-regulation of the pituitary/gonadal axis.

Predictive value of serum testosterone for type 2 diabetes risk assessment in men

BACKGROUND

Effective prevention of type 2 diabetes (T2D) requires early identification of high-risk individuals who might benefit from intervention. We sought to determine whether low serum testosterone, a novel risk factor for T2D in men, adds clinically meaningful information beyond current T2D risk models.

METHODS

The Men Androgen Inflammation Lifestyle Environment and Stress (MAILES) study population consists of 2563 community-dwelling men aged 35-80 years in Adelaide, Australia. Of the MAILES participants, 2038 (80.0 %) provided information at baseline (2002-2006) and follow-up (2007-2010). After excluding participants with diabetes (n = 317), underweight (n = 5), and unknown BMI status (n = 11) at baseline; and unknown diabetes status (n = 50) at follow-up; 1655 participants were followed for 5 years. T2D at baseline and follow-up was defined by self-reported diabetes, or fasting plasma glucose (FPG) ≥7.0 mmol/L (126.1 mg/dL), or glycated haemoglobin (HbA1c) ≥6.5 %, or diabetes medications. Risk models were tested using logistic regression models. Sensitivity, specificity, positive predictive values (PPV) were used to identify the optimal cut-off point for low serum testosterone for incident T2D and the area under the receiver operating characteristic (AROC) curve was used to summarise the predictive power of the model. 15.5 % of men had at least one missing predictor variable; addressed through multiple imputation.

RESULTS

The incidence rate of T2D was 8.9 % (147/1655) over a median follow-up of 4.95 years (interquartile range: 4.35-5.00). Serum testosterone level predicted incident T2D (relative risk 0.96 [95 % CI: 0.92,1.00], P = 0.032) independent of current risk models including the AUSDRISK, but did not improve corresponding AROC statistics. A cut-off point of <16 nmol/L for low serum testosterone, which classified about 43 % of men, returned equal sensitivity (61.3 % [95 % CI: 52.6,69.4]) and specificity (58.3 % [95 % CI: 55.6,60.9) for predicting T2D risk, with a PPV of 12.9 % (95 % CI: 10.4,15.8).

CONCLUSIONS

Low serum testosterone predicts an increased risk of developing T2D in men over 5 years independent of current T2D risk models applicable for use in routine clinical practice. Screening for low serum testosterone in addition to risk factors from current T2D risk assessment models or tools, including the AUSDRISK, would identify a large subgroup of distinct men who might benefit from targeted preventive interventions.

Clinically and pharmacologically relevant interactions of antidiabetic drugs

Patients with type 2 diabetes mellitus often require multifactorial pharmacological treatment due to different comorbidities. An increasing number of concomitantly taken medications elevate the risk of the patient experiencing adverse drug effects or drug interactions. Drug interactions can be divided into pharmacokinetic and pharmacodynamic interactions affecting cytochrome (CYP) enzymes, absorption properties, transporter activities and receptor affinities. Furthermore, nutrition, herbal supplements, patient's age and gender are of clinical importance. Relevant drug interactions are predominantly related to sulfonylureas, thiazolidinediones and glinides. Although metformin has a very low interaction potential, caution is advised when drugs that impair renal function are used concomitantly. With the exception of saxagliptin, dipeptidyl peptidase-4 (DPP-4) inhibitors also show a low interaction potential, but all drugs affecting the drug transporter P-glycoprotein should be used with caution. Incretin mimetics and sodium-glucose cotransporter-2 (SGLT-2) inhibitors comprise a very low interaction potential and are therefore recommended as an ideal combination partner from the clinical-pharmacologic point of view.

THERAPY OF ENDOCRINE DISEASE: Testosterone supplementation and body composition: results from a meta-analysis study

OBJECTIVE

The role of testosterone (T) in regulating body composition is conflicting. Thus, our goal is to meta-analyse the effects of T supplementation (TS) on body composition and metabolic outcomes.

METHODS

All randomized controlled trials (RCTs) comparing the effect of TS on different endpoints were considered.

RESULTS

Overall, 59 trials were included in the study enrolling 3029 and 2049 patients in TS and control groups respectively. TS was associated with any significant modification in body weight, waist circumference and BMI. Conversely, TS was associated with a significant reduction in fat and with an increase in lean mass as well as with a reduction of fasting glycaemia and insulin resistance. The effect on fasting glycaemia was even higher in younger individuals and in those with metabolic diseases. When only RCTs enrolling hypogonadal (total T <12  mol/l) subjects were considered, a reduction of total cholesterol as well as triglyceride (TGs) levels were also detected. Conversely, an improvement in HDL cholesterol levels as well as in both systolic and diastolic blood pressure was not observed.

CONCLUSION

Our data suggest that TS is able to improve body composition and glycometabolic profile particularly in younger subjects and in those with metabolic disturbances. Specifically designed studies are urgently needed to confirm this point.

Molecular mechanisms associated with diabetic endothelial-erectile dysfunction

Erectile dysfunction (ED) is a common complication of diabetes, affecting up to 75% of all diabetic men. Although the aetiology of diabetic ED is multifactorial, endothelial dysfunction is recognized as a mainstay in the pathophysiology of the disease. Endothelial dysfunction is induced by the detrimental actions of high glucose levels and increased oxidative stress on endothelial cells that make up the vascular lining. Besides directly injuring the endothelium, diabetes might also hamper vascular repair mechanisms of angiogenesis and vasculogenesis. These states exacerbate and maintain endothelial dysfunction, impairing vasorelaxation events and cavernosal blood perfusion, which are crucial for normal erectile function.

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

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

Trenbolone Improves Cardiometabolic Risk Factors and Myocardial Tolerance to Ischemia-Reperfusion in Male Rats With Testosterone-Deficient Metabolic Syndrome

The increasing prevalence of obesity adds another dimension to the pathophysiology of testosterone (TEST) deficiency (TD) and potentially impairs the therapeutic efficacy of classical TEST replacement therapy. We investigated the therapeutic effects of selective androgen receptor modulation with trenbolone (TREN) in a model of TD with the metabolic syndrome (MetS). Male Wistar rats (n=50) were fed either a control standard rat chow (CTRL) or a high-fat/high-sucrose (HF/HS) diet. After 8 weeks of feeding, rats underwent sham surgery or an orchiectomy (ORX). Alzet miniosmotic pumps containing either vehicle, 2-mg/kg·d TEST or 2-mg/kg·d TREN were implanted in HF/HS+ORX rats. Body composition, fat distribution, lipid profile, and insulin sensitivity were assessed. Infarct size was quantified to assess myocardial damage after in vivo ischaemia reperfusion, before cardiac and prostate histology was performed. The HF/HS+ORX animals had increased sc and visceral adiposity; circulating triglycerides, cholesterol, and insulin; and myocardial damage, with low circulating TEST compared with CTRLs. Both TEST and TREN protected HF/HS+ORX animals against sc fat accumulation, hypercholesterolaemia, and myocardial damage. However, only TREN protected against visceral fat accumulation, hypertriglyceridaemia, and hyperinsulinaemia and reduced myocardial damage relative to CTRLs. TEST caused widespread cardiac fibrosis and prostate hyperplasia, which were less pronounced with TREN. We propose that TEST replacement therapy may have contraindications for males with TD and obesity-related MetS. TREN treatment may be more effective in restoring androgen status and reducing cardiovascular risk in males with TD and MetS.

Controversies in testosterone replacement therapy: testosterone and cardiovascular disease

The role of testosterone in the cardiovascular (CV) health of men is controversial. Data suggest that both the condition and treatment of clinical hypogonadism is associated with decreased CV mortality; however, two recent studies suggest that hypogonadal subjects treated with testosterone replacement therapy have a higher incidence of new CV events. There has been increased media attention concerning the risk of CV disease in men treated with testosterone. Until date, there are no long-term prospective studies to determine safety. Literature spanning over the past 30 years has suggested that not only is there a possible increased CV risk in men with low levels of testosterone, but the benefits from testosterone therapy may even lower this risk. We review here the recent studies that have garnered such intense scrutiny. This article is intended as a thorough review of testosterone levels and CV risk, providing the clinician with the facts needed to make informed clinical decisions in managing patients with clinical hypogonadism.

Testosterone and metabolic syndrome

Controversies surround the usefulness of identifying patients with the metabolic syndrome (MetS). Many of the components are accepted risk factors for cardiovascular disease (CVD). Although the MetS as defined includes many men with insulin resistance, insulin resistance is not universal. The low total testosterone (TT) and sex hormone binding globulin (SHBG) levels in these men are best explained by the hyperinsulinism and increased inflammatory cytokines that accompany obesity and increased waist circumference. It is informative that low SHBG levels predict future development of the MetS. Evidence is strong relating low TT levels to CVD in men with and without the MetS; however, the relationship may not be causal. The recommendations of the International Diabetes Federation for managing the MetS include cardiovascular risk assessment, lifestyle changes in diet, exercise, weight reduction and treatment of individual components of the MetS. Unfortunately, it is uncommon to see patients with the MetS lose and maintain a 10% weight loss. Recent reports showing testosterone treatment induced dramatic changes in weight, waist circumference, insulin sensitivity, hemoglobin A1c levels and improvements in each of the components of the MetS are intriguing. While some observational studies have reported that testosterone replacement therapy increases cardiovascular events, the Food and Drug Administration in the United States has reviewed these reports and found them to be seriously flawed. Large, randomized, placebo-controlled trials are needed to provide more definitive data regarding the efficacy and safety of this treatment in middle and older men with the MetS and low TT levels.

Erythrocytosis and Polycythemia Secondary to Testosterone Replacement Therapy in the Aging Male

INTRODUCTION

Testosterone replacement therapy (TRT) is a common treatment for hypogonadism in aging males. Men with low to low-normal levels of testosterone have documented benefit from hormone replacement. Recent meta-analyses have revealed that increases in hemoglobin (Hb) and hematocrit (Hct) are the variants most commonly encountered. Clinically, this response is described as erythrocytosis or polycythemia secondary to TRT. However, the recent Food and Drug Administration warning regarding the risk for venothromboembolism (VTE) has made the increases in Hb and Hct of more pertinent concern. The risks associated with androgen replacement need further examination.

AIM

To review the available literature on erythrocytosis and polycythemia secondary to TRT. To discuss potential etiologies for this response, the role it plays in risk for VTE, and recommendations for considering treatment in at-risk populations.

METHODS

A literature review was performed through PubMed regarding TRT and erythrocytosis and polycythemia.

MAIN OUTCOME MEASURES

To assess the mechanisms of TRT-induced erythrocytosis and polycythemia with regard to basic science, pharmacologic preparation, and route of delivery. To review Hct and risk for thrombotic events. To offer clinical suggestions for therapy in patients at risk for veno-thrombotic events.

RESULTS

Men undergoing TRT have a 315% greater risk for developing erythrocytosis (defined as Hct > 0.52) when compared with control. Mechanisms involving iron bioavailability, erythropoietin production, and bone marrow stimulation have been postulated to explain the erythrogenic effect of TRT. The association between TRT-induced erythrocytosis and subsequent risk for VTE remains inconclusive.

CONCLUSIONS

All TRT formulations cause increases in Hb and Hct, but injectables tend to produce the greatest effect. The evidence regarding the risk for VTE with increased Hct is inconclusive. For patients with risk factors for veno-thrombotic events, formulations that provide the smallest effect on blood parameters hypothetically provide the safest option. Further trials are needed to fully evaluate the hematological side effects associated with TRT. Jones SD Jr, Dukovac T, Sangkum P, Yafi FA, and Hellstrom WJG. Erythrocytosis and polycythemia secondary to testosterone replacement therapy in the aging male. Sex Med Rev 2015;3:101-112.

Association between osteocalcin and glucose metabolism: a meta-analysis

This meta-analysis aimed to investigate the associations between osteocalcin (Ocn) and fasting plasma glucose (FPG) and glycated hemoglobin A1c (HbA1c). It was revealed that both total Ocn and undercarboxylated Ocn (unOcn) were negatively related with FPG and HbA1c, and the association of unOcn with FPG was more pronounced in men.

INTRODUCTION

The aim of this study was to investigate the strength of associations between Ocn and FPG and HbA1c using a meta-analysis approach.

METHODS

A search was carried out using the databases of PubMed, ISI Web of Science, and the Cochrane library from 2007 to 2014 to identify related studies. A pooled effect size with 95 % confidence intervals (CI) was derived.

RESULTS

The meta-analysis included 39 studies involving 23,381 participants. The overall correlation was -0.16 (95 % CI, -0.19 to -0.14) between total Ocn (tOcn) and FPG and -0.15 (95 % CI, -0.20 to -0.11) between undercarboxylated Ocn (unOcn) and FPG. In the analysis of the association between Ocn and HbA1c, the pooled correlation was -0.16 (95 % CI, -0.18 to -0.14) for tOcn and -0.16 (95 % CI, -0.23 to -0.08) for unOcn. The magnitude of the correlation between unOcn and FPG is significantly higher in men than in women (r = -0.18, 95 % CI, -0.21 to -0.14; r = -0.09, 95 % CI, -0. 13 to -0.05, respectively; P for interaction < 0.05). Similar trend was also found between unOcn and HbA1c but without significance (for men, r = -0.19, 95 % CI, -0.24 to -0.14; for women, r = -0.09, 95 % CI, -0.22 to 0.04, respectively; P for interaction > 0.05). No indication of significant publication bias was found in any method.

CONCLUSIONS

This meta-analysis demonstrated that both unOcn and tOcn were similarly and negatively correlated with FPG and HbA1c in humans. The negative correlations between unOcn and glucose metabolism appear to be more pronounced in men than in women.

Association Between Testosterone Supplementation Therapy and Thrombotic Events in Elderly Men

OBJECTIVE

To determine the prevalence of thrombotic events and all-cause mortality in men older than 65 years with hypogonadism treated with testosterone therapy (TST).

PATIENTS AND METHODS

We retrospectively reviewed the charts of 217 hypogonadal men >65 years. We compared men who received TST (n = 153) to hypogonadal men (n = 64) who did not receive TST. We evaluated all-cause mortality, prevalence of myocardial infarction (MI), transient ischemic attack (TIA), cerebrovascular accident (CVA or "stroke"), and deep vein thrombosis/pulmonary embolism (DVT/PE). All events were verified by contacting patients. We excluded men with previous thrombotic events, men previously on androgen deprivation therapy, and men who had used TST before age of 65 years.

RESULTS

Median age and Charlson Comorbidity Index of men on TST (74y; 5.1) was similar to hypogonadal men not on TST (73y, P = .48; 5.3, P = .36). Median follow-up was 3.8 vs 3.5 years (TST vs no TST). No man on TST died, whereas 5 hypogonadal men who did not receive TST died (P = .007). There were 4 thrombotic events (1 MI, 2 CVA/TIA, and 1 PE) in men who received TST and 1 event (CVA/TIA) among men who did not receive TST (P = .8). All events (1 death, 6-month follow-up) occurred at least after 2 years of follow-up.

CONCLUSION

There was increased all-cause mortality in hypogonadal men not treated with testosterone compared to men who received TST. There was no difference in prevalence of MI, TIA/CVA, or PE between patients treated with testosterone and hypogonadal men not treated with testosterone.

Testosterone in men with hypogonadism and high cardiovascular risk, Pros

Although numerous randomized studies have shown that testosterone replacement therapy (TRT) improves intermediate outcomes in patients at risk and in those with proven cardiovascular disease (CVD), results derived mainly from registries and observational studies have suggested an increased cardiovascular risk in elderly men receiving often supra-therapeutic doses of testosterone. Recent meta-analyses have shown that when testosterone has been used in patients with pre-existing cardiovascular conditions, the effect on the disease has been either beneficial or neutral. Similar results have been reported in hypo- and eugonadal men. Contrasting results have been reported by two trials of testosterone treatment in frail elderly men. Reports from poorly analyzed databases have reported an increased risk of cardiovascular events with testosterone use. More recently, a population-based study showed no increased cardiovascular risk of testosterone replacement in hypogonadal men. Available data from controlled clinical trials suggest that the use of testosterone in elderly men does not increase cardiovascular risk nor the risk of events. Studies in men with CVD, angina, or heart failure report a benefit from testosterone replacement in men with or without hypogonadism. Therefore, at present, the cardiovascular benefits of TRT in elderly men outweigh the risks. This is particularly evident in those men with pre-existing CVD.

Effects of testosterone treatment on glucose metabolism and symptoms in men with type 2 diabetes and the metabolic syndrome: a systematic review and meta-analysis of randomized controlled clinical trials

CONTEXT

The effects of testosterone treatment on glucose metabolism and other outcomes in men with type 2 diabetes (T2D) and/or the metabolic syndrome are controversial.

OBJECTIVE

To perform a systematic review and meta-analysis of placebo-controlled double-blind randomized controlled clinical trials (RCT) of testosterone treatment in men with T2D and/or the metabolic syndrome.

DATA SOURCES

A systematic search of RCTs was conducted using Medline, Embase and the Cochrane Register of controlled trials from inception to July 2014 followed by a manual review of the literature.

STUDY SELECTION

Eligible studies were published placebo-controlled double-blind RCTs published in English.

DATA EXTRACTION

Two reviewers independently selected studies, determined study quality and extracted outcome and descriptive data.

DATA SYNTHESIS

Of the 112 identified studies, seven RCTs including 833 men were eligible for the meta-analysis. In studies using a simple linear equation to calculate the homeostatic model assessment of insulin resistance (HOMA1), testosterone treatment modestly improved insulin resistance, compared to placebo, pooled mean difference (MD) -1·58 [-2·25, -0·91], P < 0·001. The treatment effect was nonsignificant for RCTs using a more stringent computer-based equation (HOMA2), MD -0·19 [-0·86, 0·49], P = 0·58). Testosterone treatment did not improve glycaemic (HbA1c) control, MD -0·15 [-0·39, 0·10], P = 0·25, or constitutional symptoms, Aging Male Symptom score, MD -2·49 [-5·81, 0·83], P = 0·14).

CONCLUSIONS

This meta-analysis does not support the routine use of testosterone treatment in men with T2D and/or the metabolic syndrome without classical hypogonadism. Additional studies are needed to determine whether hormonal interventions are warranted in selected men with T2D and/or the metabolic syndrome.