Testosterone does not adversely affect fibrinogen or tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) levels in 46 men with chronic stable angina

[Testosterone treatment]

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

The effect of transdermal gender-affirming hormone therapy on markers of inflammation and hemostasis

Background

Cardiovascular risk is increased in transgender persons using gender-affirming hormone therapy. To gain insight into the mechanism by which sex hormones affect cardiovascular risk in transgender persons, we investigated the effect of hormone therapy on markers of inflammation and hemostasis.

Methods

In this exploratory study, 48 trans women using estradiol patches plus cyproterone acetate (CPA) and 47 trans men using testosterone gel were included. They were between 18 and 50 years old and did not have a history of cardiovascular events. Measurements were performed before and after 3 and 12 months of hormone therapy.

Results

After 12 months, in trans women, systemic and endothelial inflammatory markers decreased (hs-CRP -66%, (95% CI -76; -53), VCAM-1–12%, (95% CI -16; -8)), while platelet activation markers increased (PF-4 +17%, (95% CI 4; 32), β-thromboglobulin +13%, (95% CI 2; 24)). The coagulation marker fibrinogen increased transiently, after 3 months (+15%, (95% CI 1; 32)). In trans men, hs-CRP increased (+71%, (95% CI 19; 145)); platelet activation and coagulation markers were not altered. In both trans women and trans men, leptin and adiponectin changed towards reference values of the experienced gender.

Conclusions

Platelet activation and coagulation marker concentrations increased in trans women using transdermal estradiol plus CPA, but not in trans men using testosterone. Also, concentrations of inflammatory markers decreased in trans women, while hs-CRP increased in trans men. Our results indicate that hormone therapy may affect hemostasis in transgender persons, which could be an underlying mechanism explaining the increased cardiovascular risk in this population.

Cardiovascular risk and testosterone - from subclinical atherosclerosis to lipoprotein function to heart failure

The cardiovascular (CV) benefit and safety of treating low testosterone conditions is a matter of debate. Although testosterone deficiency has been linked to a rise in major adverse CV events, most of the studies on testosterone replacement therapy were not designed to assess CV risk and thus excluded men with advanced heart failure or recent history of myocardial infarction or stroke. Besides considering observational, interventional and prospective studies, this review article evaluates the impact of testosterone on atherosclerosis process, including lipoprotein functionality, progression of carotid intima media thickness, inflammation, coagulation and thromboembolism, quantification of plaque volume and vascular calcification. Until adequately powered studies evaluating testosterone effects in hypogonadal men at increased CV risk are available (TRAVERSE trial), clinicians should ponder the use of testosterone in men with atherosclerotic cardiovascular disease and discuss benefit and harms with the patients.

Randomized controlled trials - mechanistic studies of testosterone and the cardiovascular system

Testosterone deficiency is common in men with cardiovascular disease (CVD), and randomized placebo-controlled trials (RCTs) have reported beneficial effects of testosterone therapy on exercise-induced cardiac ischemia in chronic stable angina, functional exercise capacity, maximum oxygen consumption during exercise (VO_2max) and muscle strength in chronic heart failure (CHF), shortening of the Q-T interval, and improvement of some cardiovascular risk factors. Testosterone deficiency is associated with an adverse CV risk profile and mortality. Clinical and scientific studies have provided mechanistic evidence to support and explain the findings of the RCTs. Testosterone is a rapid-onset arterial vasodilator within the coronary circulation and other vascular beds including the pulmonary vasculature and can reduce the overall peripheral systemic vascular resistance. Evidence has demonstrated that testosterone mediates this effect on vascular reactivity through calcium channel blockade (L-calcium channel) and stimulates potassium channel opening by direct nongenomic mechanisms. Testosterone also stimulates repolarization of cardiac myocytes by stimulating the ultra-rapid potassium channel-operated current. Testosterone improves cardiac output, functional exercise capacity, VO_2max and vagally mediated arterial baroreceptor cardiac reflex sensitivity in CHF, and other mechanisms. Independent of the benefit of testosterone on cardiac function, testosterone substitution may also increase skeletal muscle glucose metabolism and enhance muscular strength, both factors that could contribute to the improvement in functional exercise capacity may include improved glucose metabolism and muscle strength. Testosterone improves metabolic CV risk factors including body composition, insulin resistance, and hypercholesterolemia by improving both glucose utilization and lipid metabolism by a combination of genomic and nongenomic actions of glucose uptake and utilization expression of the insulin receptor, glucose transporters, and expression on regulatory enzymes of key metabolic pathways. The effect on high-density lipoprotein-cholesterol (HDL-C) differs between studies in that it has been found to fall, rise, or have no change in levels. Testosterone replacement can suppress the levels of circulating pro-inflammatory cytokines and stimulate the production of interleukin-10 (IL-10) which has anti-inflammatory and anti-atherogenic actions in men with CVD. No effect on C-reactive protein has been detected. No adverse effects on clotting factors have been detected. RCTs have not clearly demonstrated any significant evidence that testosterone improves or adversely affects the surrogate markers of atherosclerosis such as reduction in carotid intima thickness or coronary calcium deposition. Any effect of testosterone on prevention or amelioration of atherosclerosis is likely to occur over years as shown in statin therapy trials and not months as used in testosterone RCTs. The weight of evidence from long-term epidemiological studies supports a protective effect as evidenced by a reduction in major adverse CV events (MACEs) and mortality in studies which have treated men with testosterone deficiency. No RCT where testosterone has been replaced to the normal healthy range has reported a significant benefit or adverse effect on MACE nor has any recent meta-analysis.

Testosterone and the Heart

Testosterone (T) has a number of important effects on the cardiovascular system. In men, T levels begin to decrease after age 40, and this decrease has been associated with an increase in all-cause mortality and cardiovascular (CV) risk. Low T levels in men may increase their risk of developing coronary artery disease (CAD), metabolic syndrome, and type 2 diabetes. Reduced T levels in men with congestive heart failure (CHF) portends a poor prognosis and is associated with increased mortality. Studies have reported a reduced CV risk with higher endogenous T concentration, improvement of known CV risk factors with T therapy, and reduced mortality in T-deficient men who underwent T replacement therapy versus untreated men. Testosterone replacement therapy (TRT) has been shown to improve myocardial ischemia in men with CAD, improve exercise capacity in patients with CHF, and improve serum glucose levels, HbA1c, and insulin resistance in men with diabetes and prediabetes. There are no large long-term, placebo-controlled, randomized clinical trials to provide definitive conclusions about TRT and CV risk. However, there currently is no credible evidence that T therapy increases CV risk and substantial evidence that it does not. In fact, existing data suggests that T therapy may offer CV benefits to men.

Protective effects of physiological testosterone on advanced glycation end product‑induced injury in human endothelial cells

The effect of testosterone, a sex steroid, on endothelial cells is controversial as it is uncertain if it has a protective effect on them. Whether physiological testosterone can inhibit the deleterious effects of advanced glycation end products (AGEs) on endothelial cells remains to be elucidated. The present study focused on elucidating the effect of testosterone on the injury of endothelial cells induced by AGEs. Human umbilical vein endothelial cells (HUVECs) were cultured in vitro and treated with AGEs in the presence or absence of various concentrations of testosterone. The cell viability in each group was measured using an MTS assay. Early-stage apoptosis was detected using flow cytometry with Annexin V-fluorescein isothiocyanate/propidium iodide double staining, and the expression levels of apoptosis-associated proteins, B cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax) and caspase-3, were determined using western blot analysis. Oxidative stress and pro-inflammatory parameters in the medium were evaluated using an enzyme-linked immunosorbent assay. The MTS results showed that AGEs significantly decreased the proliferation of HUVECs, whereas a physiological concentration of testosterone alleviated this damage. Physiological concentrations of testosterone protected the HUVECs from AGE-induced apoptosis, mediated by caspase-3 and Bax/Bcl-2. In addition, treatment of the HUVECs with AGEs caused a significant decrease in anti-oxidative parameters, but increased the concentrations of malondialdehyde and tumor necrosis factor-α. The activation of Janus kinase 2 and signal transducer and activator of transcription 3 was significantly increased by incubation with AGEs. However, pre-incubation with a physiological concentration of testosterone attenuated these changes. Therefore, the data obtained in the present study established the potential role of physiological testosterone in ameliorating AGE-induced damage in HUVECs.

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.

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.

Roles of Testosterone Replacement in Cardiac Ischemia-Reperfusion Injury

Testosterone is an anabolic steroid hormone, which is the major circulating androgen hormone in males. Testosterone levels decreasing below the normal physiological levels lead to a status known as androgen deficiency. Androgen deficiency has been shown to be a major risk factor in the development of several disorders, including obesity, metabolic syndrome, and ischemic heart disease. In the past decades, although several studies from animal models as well as clinical studies demonstrated that testosterone exerted cardioprotection, particularly during ischemia-reperfusion (I/R) injury, other preclinical and clinical studies have shown an inverse relationship between testosterone levels and cardioprotective effects. As a result, the effects of testosterone replacement on the heart remain controversial. In this review, reports regarding the roles of testosterone replacement in the heart following I/R injury are comprehensively summarized and discussed. At present, it may be concluded that chronic testosterone replacement at a physiological dose demonstrated cardioprotective effects, whereas acute testosterone replacement can cause adverse effects in the I/R heart.

A comprehensive study of ovine haemostasis to assess suitability to model human coagulation

INTRODUCTION

Similarities in size, anatomy and physiology have supported the use of sheep to model a wide range of human diseases, including coagulopathy. However, coagulation studies involving sheep are limited by the absence of high quality data defining normal ovine coagulation and fibrinolysis.

MATERIALS AND METHODS

Full blood examination, routine and specialised coagulation tests, rotational thromboelastometry and whole blood platelet aggregometry was performed on 50 healthy Samm & Border Leicester Cross ewes and compared to corresponding human ranges. Intraspecies breed and gender variability was investigated by comparison to a smaller population of 13 healthy Merino wethers.

RESULTS

Ovine coagulation was similar to human according to routine coagulation methods (PT, aPTT, TCT, Fib(C)) and some specialised coagulation tests (vWF, AT, Plasmin Inh). Despite these similarities, ovine secondary haemostasis demonstrated substantial differences to that of human. Rapid initiation of the contact activation pathway, high levels of FVIII, low Protein C, greater overall clot firmness and a reduced capacity for clot lysis was documented in sheep. In addition, ADP and collagen agonists precipitated a reduced primary haemostatic response in sheep relative to human. Intraspecies differences in whole blood platelet aggregometry between the cohorts of sheep indicate the need for breed-specific normal ranges.

CONCLUSIONS

The application of a board spectrum of coagulation assays has enabled elucidation of the similarities as well as differences between ovine and human coagulation. The new knowledge generated from this study will guide the design of future translational coagulation studies in ovine models.

The Effect of Testosterone on Cardiovascular Disease

Cardiovascular disease is the leading cause of death in the United States. Testosterone is the principal male sex hormone and plays an important role in men’s health and well-being. Historically, testosterone was believed to adversely affect cardiovascular function. However, contemporary literature has refuted this traditional thinking; testosterone has been suggested to have a protective effect on cardiovascular function through its effects on the vascular system. Data from modern research indicate that hypogonadism is closely related to the development of various cardiovascular risk factors, including hyperlipidemia and insulin resistance. Several studies have demonstrated beneficial effects of testosterone supplementation therapy on reversing symptoms of hypogonadism and improving cardiovascular disease risk profiles. In this review, we perform a critical analysis on the association between testosterone and cardiovascular disease.

Androgen activity and markers of inflammation among men in NHANES III

OBJECTIVES

Inflammation contributes to chronic diseases. Lower serum testosterone among men is associated with less inflammation, yet immune defense is thought to trade-off against reproduction with androgens adversely affecting immune function. Anti-androgens are effective at castrate levels of serum testosterone, suggesting serum testosterone may not capture all androgen activity. The association of two androgen biomarkers with key markers of inflammation was examined.

METHODS

The adjusted association of serum testosterone and androstanediol glucuronide with C-reactive protein, white blood cell, granulocyte and lymphocyte count, fibrinogen, and hemoglobin, as a control outcome because testosterone administration raises hemoglobin, were examined in a nationally representative sample of 1,490 US men from the National Health and Nutrition Examination Survey III phase 1 (1988-1991) using multivariable linear regression.

RESULTS

Serum testosterone and androstanediol glucuronide were weakly correlated (0.13). Serum testosterone was associated with lower white blood cell count [-0.26 × 10(-9) per standard deviation, 95% confidence interval (CI) -0.37 to -0.14] and granulocyte count (-0.21 × 10(-9) , 95% CI -0.29 to -0.13) but not with hemoglobin (0.02 g/l, 95% CI -0.89 to 0.92), adjusted for age, education, race/ethnicity, smoking, and alcohol. Similarly adjusted, androstanediol glucuronide was not associated with white blood cell count (0.10 × 10(-9) , 95% CI -0.05 to -0.25), granulocyte count (0.12 × 10(-9) , 95% CI -0.02 to 0.25), or fibrinogen (0.05 g/l, 95% CI -0.004 to 0.11), but was with hemoglobin (0.70 g/l, 95% CI 0.07 to 1.32).

CONCLUSIONS

Different androgen biomarkers had different associations with inflammatory markers, highlighting the need to consider several androgen biomarkers. The possibility remains that androgens may generate inflammatory processes with implications for chronic diseases.

Testosterone and the metabolic syndrome

Metabolic syndrome and testosterone deficiency in men are closely Linked. Epidemiological studies have shown that Low testosterone Levels are associated with obesity, insulin resistance and an adverse Lipid profile in men. Conversely in men with metabolic syndrome and type 2 diabetes have a high prevalence of hypogonadism. Metabolic syndrome and Low testosterone status are both independently associated with increased all-cause and cardiovascular mortality. Observational and experimental data suggest that physiological replacement of testosterone produces improvement in insulin resistance, obesity, dyslipidae-mia and sexual dysfunction along with improved quality of Life. However, there are no Long-term interventional studies to assess the effect of testosterone replacement on mortality in men with Low testosterone Levels. This article reviews the observational and interventional clinical data in relation to testosterone and metabolic syndrome.

Testosterone deficiency: a risk factor for cardiovascular disease?

Male gender is a major risk factor for premature cardiovascular death, a relationship not yet explained. Low testosterone in men is a risk factor for the metabolic syndrome and type 2 diabetes and is associated independently with individual components of the metabolic syndrome--visceral obesity, insulin resistance, hyperglycemia, hypertension and dyslipidemia. Epidemiological studies report increased mortality in men with low testosterone. Testosterone replacement in the short-term reduces waist circumference, cholesterol and circulating pro-inflammatory cytokines and improves insulin sensitivity and glycemic control in diabetics. Testosterone also has beneficial effects on cardiac ischemia, angina and chronic heart failure. This manuscript reviews the current evidence supporting a link between low testosterone and cardiovascular disease, highlighting the need for larger, longer-term studies.

Mitogen-activated protein kinases pathway is involved in physiological testosterone-induced tissue factor pathway inhibitor expression in endothelial cells

The mechanism of testosterone inducing the tissue factor pathway inhibitor (TFPI) in protecting against thrombosis is unknown. We aimed to elucidate the mechanisms involved in the induction by observing, in human umbilical vein endothelial cells (HUVECs), the phosphorylation of mitogen-activated protein kinases (MAPKs), a major cell signaling system. The level of testosterone regulating several signaling pathways, including extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun-N-terminal kinase (JNK), and p38 MAPK, was measured by western blot in HUVECs. ELISA and quantitative real-time reverse transcriptase-PCR were used to analyze TFPI expression after blocking ERK1/2 (with PD98059) or JNK (with SP600125) pathway in HUVECs. Testosterone-induced a rapid phosphorylation of ERK1/2, JNK and p38 MAPK in HUVECs, which could not be inhibited by androgen receptor antagonist flutamide. Blocking ERK1/2 or JNK pathway could significantly impair testosterone-induced TFPI at both translational and transcriptional levels in HUVECs. Testosterone at a physiological concentration may help to prevent thrombosis development by stimulating TFPI expression in HUVECs, partly through the ERK1/2 and JNK MAPK pathway.

Long-term benefits of testosterone replacement therapy on angina threshold and atheroma in men

INTRODUCTION

In short-term studies, testosterone replacement therapy has been shown to protect male subjects from exercise-induced ischaemia and modify cardiovascular risk factors such as insulin resistance, fat mass and lipid profiles.

METHODS

This randomised parallel group controlled trial was designed to assess the treatment effect of testosterone therapy (Nebido) compared with placebo in terms of exercise-induced ischaemia, lipid profiles, carotid intima-media thickness (CIMT) and body composition during 12 months treatment in men with low testosterone levels and angina.

RESULTS

A total of 15 men were recruited but 13 (n=13) reached adequate duration of follow-up; seven were treated with testosterone and six with placebo. Testosterone increased time to ischaemia (129+/-48 s versus 12+/-18, P=0.02) and haemoglobin (0.4+/-0.6 g/dl versus -0.03+/-0.5, P=0.04), and reduced body mass index (-0.3 kg/m(2) versus 1.3+/-1, P=0.04) and triglycerides (-0.36+/-0.4 mmol/l versus 0.3+/-1.2, P=0.05). The CIMT decreased in the testosterone group more than placebo, but full between group analyses suggested this was only a statistical trend (-0.5+/-0.1 vs -0.09+/-0.06, P=0.16). There were no significant effects on serum prostate specific antigen, total or high-density lipoprotein cholesterol; or on mood and symptom scores as assessed by Seattle Angina Score and EuroQol.

CONCLUSION

The protective effect of testosterone on myocardial ischaemia is maintained throughout treatment without decrement. Previously noted potentially beneficial effects of testosterone on body composition were confirmed and there were no adverse effects.

Left ventricular dysfunction in Klinefelter syndrome is associated to insulin resistance, abdominal adiposity and hypogonadism

OBJECTIVE

Epidemiological data suggest there is an increased risk of dying from heart disease among patients with Klinefelter syndrome (KS). Due to high prevalence of hypogonadism and metabolic syndrome, we speculated that patients with KS may have subclinical changes in the left ventricular function. Therefore, the aim was to assess left ventricular long axis function by tissue Doppler echocardiography in patients with KS and relate these findings to the metabolic status and testosterone levels.

DESIGN

Cross-sectional study. Out-patient clinic.

PATIENTS

We investigated 25 unselected patients with KS, recruited from endocrine and fertility clinics. Twenty-five age-matched males served as controls.

MEASUREMENTS

Left ventricular systolic long axis function (velocities and strain rate) assessed by tissue Doppler echocardiography related to free testosterone, fasting values of plasma glucose, insulin, homeostasis model assessment (HOMA)-index, cholesterol and triglycerides in addition to dual energy X-ray absorptiometry (DEXA) scan derived assessment of truncal body fat.

RESULTS

The long axis function was significantly reduced in patients with KS (peak systolic velocities 4.4 +/- 1.3 vs. 5.3 +/- 1.0 cm/s, P < 0.01 and strain rate -1.3 +/- 0.3 vs.-1.6 +/- 0.3 s(-1), P < 0.01). However, the ventricular dysfunction was mainly attributed KS patients with metabolic syndrome. The peak systolic velocities were significantly correlated to truncal body fat (r = -0.72, P < 0.01) and free testosterone (r = 0.63, P < 0.01), but uncorrelated to plasma glucose, insulin and HOMA-index.

CONCLUSION

Systolic long axis function is decreased in patients with KS and metabolic syndrome. The decrease in myocardial systolic function was significantly related to truncal body fat and hypogonadism, but not correlated to insulin sensitivity.

Androgen deficiency as a predictor of metabolic syndrome in aging men: an opportunity for intervention?

The prevalence of metabolic syndrome is increasing globally and is an important risk factor for the development of cardiovascular disease. Longitudinal population studies have found that low testosterone status in men is a risk factor for the later development of metabolic syndrome. Men with metabolic syndrome and type 2 diabetes mellitus have a higher incidence of hypotestosteronaemia. Furthermore, in men, testosterone levels are inversely associated with the degree of carotid and aortic atherosclerosis. Early interventional, short-term studies have shown that testosterone replacement therapy has a beneficial effect on visceral obesity, insulin sensitivity, glycaemic control and lipid profiles in men with diagnosed hypogonadism with and without diabetes. The effect of testosterone therapy on atherogenesis in men is unknown; however, animal studies have shown that testosterone is atheroprotective and can ameliorate the degree of atherosclerosis. Testosterone is an arterial vasodilator and has been shown to improve myocardial ischaemia in men with coronary artery disease. This review discusses the role that testosterone may play in the pathogenesis of metabolic syndrome in men and also examines the potential role of testosterone replacement therapy in this condition.

Testosterone for the aging male; current evidence and recommended practice

An international consensus document was recently published and provides guidance on the diagnosis, treatment and monitoring of late-onset hypogonadism (LOH) in men. The diagnosis of LOH requires biochemical and clinical components. Controversy in defining the clinical syndrome continues due to the high prevalence of hypogonadal symptoms in the aging male population and the non-specific nature of these symptoms. Further controversy surrounds setting a lower limit of normal testosterone, the limitations of the commonly available total testosterone result in assessing some patients and the unavailability of reliable measures of bioavailable or free testosterone for general clinical use. As with any clinical intervention testosterone treatment should be judged on a balance of risk versus benefit. The traditional benefits of testosterone on sexual function, mood, strength and quality of life remain the primary goals of treatment but possible beneficial effects on other parameters such as bone density, obesity, insulin resistance and angina are emerging and will be reviewed. Potential concerns regarding the effects of testosterone on prostate disease, aggression and polycythaemia will also be addressed. The options available for treatment have increased in recent years with the availability of a number of testosterone preparations which can reliably produce physiological serum concentrations.

Blood coagulation and fibrinolysis in male patients with hypogonadotropic hypogonadism: plasma factor V and factor X activities increase in hypogonadotropic hypogonadism

BACKGROUND AND OBJECTIVES

In men, androgens have both pro- and anti-thrombotic effects. Androgen deficiency in men is associated with an increased incidence of cardiovascular disease (CVD). However, the influence of hypogonadism on hemostasis is controversial. Little is known about hemostatic features of male patients with idiopathic hypogonadotropic hypogonadism (IHH). Thus, the aim of the present study was to evaluate the markers of endogenous coagulation and fibrinolysis, and to investigate the relationships between endogenous sex hormones and hemostatic parameters and serum lipid profile in men with IHH.

DESIGN AND METHODS

Seventeen patients with IHH and 20 age-matched healthy controls were included in the study. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, factors (F) V, VII, VIII, IX, and X activities, von Willebrand factor (vWF), antithrombin III (AT III), protein C, protein S, tissue plasminogen activator (t-PA), and tissue plasminogen activator inhibitor (PAI-1), as well as common lipid variables, were measured. The relationships between serum sex hormones and these hemostatic parameters were examined.

RESULTS

Compared with the control subjects, platelet count, FV, FX, and protein C activities were significantly increased in patients with IHH (p<0.01, p<0.05, p<0.01, and p<0.05, respectively), whereas AT III was decreased (p<0.05). Fibrinogen, FVIII, vWF, t-PA, PAI-1, and the other coagulation/fibrinolysis parameters and lipid profile in patients with IHH were not different from the controls. In patients with IHH, we showed that serum LH level was negatively correlated with fibrinogen (r: -0.78, p<0.01) and protein C (r: -0.55, p<0.05) and positively correlated with t-PA (r: 0.53, p<0.05). Serum FSH levels inversely correlated with fibrinogen (r: -0.75, p<0.01).

INTERPRETATION AND CONCLUSIONS

We found some differences in the hemostatic parameters between the patients with IHH and healthy controls. Increased platelet count, FV and FX activities and decreased AT III levels in patients with IHH represent a potential hypercoagulable state, which might augment the risk for atherosclerotic and atherothrombotic complications. Therefore, IHH may be associated with an increased risk of CVD. However, sex hormones may play a role at different levels of the complex hemostatic system in patients with IHH.

Why men's hearts break: cardiovascular effects of sex steroids

Coronary artery disease (CAD) mortality differs in men and women, leading to the speculation that differences in sex steroids contribute to risk. Controlled clinical trials have shown that estrogen replacement is not cardioprotective in certain women, and recent cross-sectional studies associate low testosterone with a greater incidence of CAD in men. Testosterone has demonstrated effects on insulin resistance, obesity, myocardium, coagulation, inflammation, vasodilation, and endothelial function. Imbalance of sex steroids contributes to adverse cardiac effects in men.

Physiological testosterone stimulates tissue plasminogen activator and tissue factor pathway inhibitor and inhibits plasminogen activator inhibitor type 1 release in endothelial cells

There is a striking gender difference in atherosclerotic vascular disease. For decades, testosterone was considered detrimental to the cardiovascular system. Recent studies, however, have presented some alternative results. The aim of this study was to evaluate the effect of testosterone, using physiological and supraphysiological concentrations, on antigen and mRNA levels of tissue plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI-1), and tissue factor pathway inhibitor (TFPI) released by human umbilical vein endothelial cells and to investigate the cellular mechanism. Cells within 2-3 passages were cultured in 25 cm(2) flasks or plated onto 96-well plates with a density of about 1 x 10(5) cells/mL as recommended. The cells were incubated in the presence or absence of testosterone (3, 30, 3 x 10(3), 3 x 10(4) nmol/L) for 48 h. Levels of tPA, PAI-1, and TFPI antigen were assayed with ELISA kits. Reverse transcriptase PCR was carried out to detect tPA, PAI-1, and TFPI mRNA levels. Cells were incubated in androgen-receptor antagonist (flutamide 10 micromol/L) or aromatase inhibitor (aminoglutethimide 50 micromol/L) for 3 h, and then the experiments were repeated. Testosterone at a physiologic concentration (30 nmol/L) increased the antigen levels of tPA and TFPI significantly (P < 0.05). However, tPA and TFPI levels were markedly reduced (P < 0.05) at a larger dose (3 x 10(4) nmol/L). On the other hand, PAI-1 antigen levels decreased significantly at the testosterone concentrations ranging from 3 to 3 x 10(4) nmol/L (P < 0.05). The change in the levels of tPA and TFPI were reflected in the corresponding change in mRNA levels. Flutamide attenuated the effect of testosterone at physiological concentration (30 nmol/L). The results demonstrated that testosterone at physiological concentrations may have a beneficial influence on the haemostatic system through enhancement of anticoagulant activity, resulting from stimulation of TFPI and tPA expression and inhibition of PAI-1 secretion by the endothelium.

Testosterone and ageing: what have we learned since the Institute of Medicine report and what lies ahead?

A 2003 report by the Institute of Medicine (IOM) surveyed the literature on the benefits and risks of testosterone replacement therapy in older men and identified knowledge gaps and research needs. This review summarises some key studies published since the IOM report. The possible relationship of testosterone to risk of prostate cancer remains a concern; however, no new evidence has emerged to suggest that testosterone replacement therapy increases the risk. Recent studies have demonstrated that hypogonadism in men may be more prevalent than previously thought, is strongly associated with metabolic syndrome, and may be a risk factor for type 2 diabetes and cardiovascular disease. Clinical studies have shown that testosterone replacement therapy in hypogonadal men improves metabolic syndrome indicators and cardiovascular risk factors. Maintaining testosterone concentrations in the normal range has been shown to contribute to bone health, lean muscle mass, and physical and sexual function, suggesting that testosterone replacement therapy may help to prevent frailty in older men. Based on current knowledge, testosterone replacement therapy is unlikely to pose major health risks in patients without prostate cancer and may offer substantial health benefits. Larger, longer-term randomised studies are needed to fully establish the effects of testosterone replacement therapy.

Testosterone and atherosclerosis in aging men: purported association and clinical implications

Two of the strongest independent risk factors for coronary heart disease (CHD) are increasing age and male sex. Despite a wide variance in CHD mortality between countries, men are consistently twice as likely to die from CHD than their female counterparts. This sex difference has been attributed to a protective effect of female sex hormones, and a deleterious effect of male sex hormones, upon the cardiovascular system. However, little evidence suggests that testosterone exerts cardiovascular harm. In fact, serum levels of testosterone decline with age, and low testosterone is positively associated with other cardiovascular risk factors. Furthermore, testosterone exhibits a number of potential cardioprotective actions. For example, testosterone treatment is reported to reduce serum levels of the pro-inflammatory cytokines interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha, and to increase levels of the anti-inflammatory cytokine IL-10; to reduce vascular cell adhesion molecule (VCAM)-1 expression in aortic endothelial cells; to promote vascular smooth muscle and endothelial cell proliferation; to induce vasodilatation and to improve vascular reactivity, to reduce serum levels of the pro-thrombotic factors plasminogen activator inhibitor (PAI)-1 and fibrinogen; to reduce low-density lipoprotein-cholesterol (LDL-C); to improve insulin sensitivity; and to reduce body mass index and visceral fat mass. These actions of testosterone may confer cardiovascular benefit since testosterone therapy reduces atheroma formation in cholesterol-fed animal models, and reduces myocardial ischemia in men with CHD. Consequently, an alternative hypothesis is that an age-related decline in testosterone contributes to the atherosclerotic process. This is supported by recent findings, which suggest that as many as one in four men with CHD have serum levels of testosterone within the clinically hypogonadal range. Consequently, restoration of serum levels of testosterone via testosterone replacement therapy could offer cardiovascular, as well as other, clinical advantages to these individuals.