Association between serum testosterone concentration and carotid atherosclerosis in men with type 2 diabetes

Hypogonadotrophic hypogonadism in type 2 diabetes

Recent work shows a high prevalence of low testosterone and inappropriately low luteinizing hormone (LH) and follicle stimulating hormone (FSH) concentrations in type 2 diabetes. This syndrome of hypogonadotrophic hypogonadism (HH) is associated with obesity in patients with type 2 diabetes. However, the duration of diabetes or HbA1c are not related to HH. Furthermore, recent data show that HH is not associated with type 1 diabetes. C-reactive protein concentrations have been shown to be elevated in patients with HH and are inversely related to plasma testosterone concentrations. This inverse relationship between plasma free testosterone and C- reactive protein concentrations in patients with type 2 diabetes suggests that inflammation may play an important role in the pathogenesis of this syndrome. This is of interest since inflammatory mechanisms may have a cardinal role in the pathogenesis of insulin resistance. It is also relevant that in the mouse, deletion of the insulin receptor in neurons leads to HH in addition to a state of systemic insulin resistance. It has also been shown that insulin facilitates the secretion of gonadotrophin releasing hormone (GnRH) from neuronal cell cultures. Thus, HH may be the result of insulin resistance at the level of the GnRH secreting neuron. Low testosterone concentrations are also related to an increase in total and regional adiposity. This review discusses these issues and attempts to make the syndrome relevant as a clinical entity. Clinical trials are required to determine whether testosterone replacement alleviates insulin resistance and inflammation. In addition, low testosterone levels are associated with an increase in cardiovascular events. Testosterone therapy may therefore, reduce cardiovascular risk. This important aspect requires further investigation.

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.

Insulin resistance syndrome and glucose dysregulation in the elderly

The incidence of insulin resistance in the geriatric population is growing as this population grows. The management of hyperglycemia and its associated risk factors depends on an expanding understanding of the underlying pathophysiology and progression of disease and of the currently available and future therapeutics, which are continually evolving. There is a major need for studies in the long-term care setting to determine the appropriate standard of care in prevention and treatment of metabolic dysregulation.

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.

Association between serum estradiol concentrations and carotid atherosclerosis in men with type 2 diabetes mellitus

The aim of this study was to evaluate relationships between serum estradiol concentration and carotid atherosclerosis in addition to major cardiovascular risk factors in men with type 2 diabetes mellitus because previous reports concerning the role of estrogen on atherosclerosis in men are conflicting. Serum estradiol concentrations were measured in 305 consecutive men with type 2 diabetes mellitus. Relationships were evaluated between serum estradiol concentration and carotid atherosclerosis, as determined by ultrasonographically evaluated intima-media thickness (IMT) and plaque score, in a subgroup of 144 diabetic patients, as well as major cardiovascular risk factors, including age, blood pressure, and lipid concentrations. An inverse correlation was found between serum estradiol concentration and IMT (r = -0.174, P = .0369), but no correlation was found between serum estradiol concentration and plaque score. Patients with serum estradiol concentrations in the lowest tertile displayed significantly higher IMT compared with patients in the highest tertile (P = .0083). Serum estradiol concentration was not a determinant of IMT (beta = -.121, P = .1396) in the multiple regression analysis. An inverse correlation was found between serum estradiol concentration and triglyceride concentration (r = -0.136, P = .0186). In conclusion, serum estradiol concentration is inversely associated with carotid atherosclerosis as determined by ultrasonographically evaluated IMT in men with type 2 diabetes mellitus.

State of the Art Reviews: Male Menopause: Fact or Fiction?

The possible existence of a menopause-like process in aging men has been speculated, given certain age-related hormonal and other biological changes noted to occur. Specifically, a slow decline in serum testosterone levels has been reported to occur with normal male aging. Androgen deficiency, which may result from this process, could have an effect on various systems and physiologic parameters, including bone density, body composition, sexual function, and the cardiovascular system, thus significantly affecting health and quality-of-life issues in older men. There has been an increasing interest in evaluating the possible use of testosterone replacement in preventing some detrimental aspects of aging and age-related hypogonadism, as well as in the investigation of the potential adverse effects of this therapy on different target organs. It is the purpose of this review to summarize currently available information with regard to the changes in testosterone and other hormones in older men, discuss their possible clinical manifestations and relationship with other age-related changes, and provide an updated description of testosterone replacement therapy for older men, including its indications, formulations, and safety considerations.

Low serum testosterone concentration in middle-aged men with type 2 diabetes

Low concentrations of endogenous androgens have been linked with insulin resistance and atherosclerosis. Men with diabetes have been reported to have lower serum testosterone concentration than non-diabetic men; however, there has never been a large study. The aim of this study was to investigate if endogenous androgen concentration is certainly lower in a relatively large number of Japanese patients with type 2 diabetes compared with healthy men, and to identify what factors may be associated with low serum testosterone concentrations in men with type 2 diabetes. Serum free testosterone concentrations were measured in 524 healthy men and in 331 consecutive Japanese men with type 2 diabetes between 40 and 69 years old. In addition, we investigated the relationships between serum free testosterone concentration and luteinizing hormone (LH) concentration as well as major cardiovascular risk factors including age, blood pressure, plasma lipid concentration, glycemic control (HbA(1c)), and BMI. Serum free testosterone concentrations were lower in men with type 2 diabetes than in healthy men in the 40-49 years group (10.9 +/- 3.3 vs. 14.0 +/- 3.6 pg/ml, P<0.0001), in the 50-59 years group (10.4 +/- 3.2 vs. 12.1 +/- 2.9 pg/ml, P<0.0001), and in the 60-69 years group (9.5 +/- 2.6 vs. 10.5 +/- 2.9 pg/ml, P = 0.0104). A negative correlation was found between serum free testosterone and LH concentrations (r = -0.326, P<0.0001). In conclusion, serum free testosterone concentration is certainly lower in a relatively large number of Japanese patients with type 2 diabetes compared with healthy men with each decade of life between 40 and 69 years old.

Relationship between low serum endogenous androgen concentrations and arterial stiffness in men with type 2 diabetes mellitus

The aim of this study was to evaluate the relationship between arterial stiffness determined by pulse wave velocity (PWV) and serum endogenous androgen concentrations as well as major cardiovascular risk factors in men with type 2 diabetes mellitus. Serum free testosterone and dehydroepiandrosterone sulfate (DHEA-S) concentrations were measured in 268 men with type 2 diabetes mellitus. Relationships between PWV and serum endogenous androgen concentrations as well as major cardiovascular risk factors, including age, blood pressure, serum lipid concentration, glycemic control (hemoglobin A(1c)), body mass index, and degree of albuminuria, were evaluated. Positive correlations were found between PWV and age (r = 0.491, P < .0001), duration of diabetes (r = 0.320, P < .0001), systolic blood pressure (r = 0.292, P < .0001), and log (urinary albumin excretion) (r = 0.269, P < .0001). Inverse correlations were found between serum free testosterone concentration and PWV (r = -0.228, P = .0003) and between serum DHEA-S concentration and PWV (r = -0.252, P = .0002) in men with type 2 diabetes mellitus. Pulse wave velocity was significantly greater in patients with lower concentrations of free testosterone (<10 pg/mL) than in patients with higher concentrations of free testosterone (1864 +/- 359 vs 1736 +/- 327 cm/s; P = .0053). Pulse wave velocity also was significantly greater in patients with lower concentrations of DHEA-S (<1000 ng/mL) than in patients with higher concentrations of DHEA-S (1843 +/- 371 vs 1686 +/- 298 cm/s; P = .0008). Multiple regression analysis identified both serum free testosterone concentration (beta = -.151, P = .0150) and serum DHEA-S concentration (beta = -.200, P = .0017) as independent determinants of PWV. In conclusion, serum endogenous androgen concentrations are inversely associated with arterial stiffness determined by PWV in men with type 2 diabetes mellitus, which is true for men in general based on other works.

Association between serum testosterone concentration and collagen degradation fragments in men with type 2 diabetes mellitus

The aim of the present study was to evaluate relationships between serum endogenous androgens and urinary concentration of cross-linked N-telopeptides of type I collagen (NTx), a bone resorption marker, in men with type 2 diabetes mellitus because low androgen concentrations are associated with both osteoporosis and cardiovascular disease. Relationships between serum free testosterone and urinary NTx concentrations were investigated in 246 consecutive men with type 2 diabetes mellitus. In addition, relationships between urinary NTx concentration and other variables including age, duration of diabetes, blood pressure, serum lipid concentration, hemoglobin A(1c), and body mass index were evaluated. Urinary NTx concentrations were 27.8 (26.4-29.3) nmol of bone collagen equivalent per millimole of creatinine, correlating inversely with serum free testosterone (r = -0.263, P < .0001). Multiple regression analysis identified serum free testosterone (beta = -.292, P < .0001), hemoglobin A(1c) (beta = .144, P = .0404), and smoking status (beta = .143, P = .0402) as independent determinants of urinary NTx. In conclusion, serum free testosterone concentration correlated inversely with urinary NTx concentration, which may partly account for an observed link between osteoporosis and cardiovascular disease in men with type 2 diabetes mellitus.

Metabolic syndrome is not associated with markers of subclinical atherosclerosis, serum adiponectin and endogenous androgen concentrations in Japanese men with Type 2 diabetes

AIMS

Metabolic syndrome is characterized by its association with certain cardiovascular disease risk factors. The aim of this study was to investigate the relationships between metabolic syndrome and markers of subclinical atherosclerosis, serum adiponectin and endogenous androgen concentrations in Japanese men with Type 2 diabetes.

METHODS

Using the 2005 International Diabetes Federation (IDF) definition, we assessed the prevalence of the metabolic syndrome in 424 consecutive men with Type 2 diabetes aged 40-75 years in a cross-sectional study. We compared characteristics including ultrasonographic carotid atherosclerosis markers, pulse-wave velocity (PWV), and serum adiponectin, free testosterone, and dehydroepiandrosterone sulphate (DHEA-S) concentrations in diabetic patients with and without the metabolic syndrome.

RESULTS

The prevalence of the metabolic syndrome in Japanese men with Type 2 diabetes was 46.9%. Men with the metabolic syndrome had higher urinary albumin excretion rate than those without. Carotid intima-media thickness (0.97 +/- 0.26 vs. 0.91 +/- 0.18 mm), plaque score [3.3 (1.5-8.1) vs. 3.8 (1.3-6.2)], PWV (1818 +/- 331 vs. 1749 +/- 331 cm/s) and ankle-brachial index (1.10 +/- 0.14 vs. 1.08 +/- 0.16) did not differ significantly between patients with and without the metabolic syndrome. Similarly, serum adiponectin [3.70 (2.06-6.09) vs. 4.65 (3.09-7.02) microg/ml], free testosterone (36.4 +/- 10.7 vs. 34.7 +/- 11.1 pmol/l), and DHEA-S concentrations (3.29 +/- 1.83 vs. 3.17 +/- 1.63 micromol/l) did not differ significantly between groups,

CONCLUSIONS

The metabolic syndrome, as defined by the IDF, is not significantly associated with subclinical atherosclerosis markers, serum adiponectin, or endogenous androgen concentrations in Japanese men with Type 2 diabetes.

PKCδ mediates anti-proliferative, pro-apoptic effects of testosterone on coronary smooth muscle

Sex hormone status has emerged as an important modulator of coronary physiology and cardiovascular disease risk in both males and females. Our previous studies have demonstrated that testosterone increases protein kinase C (PKC) δ expression and activity in coronary smooth muscle (CSMC). Because PKCδ has been implicated in regulation of proliferation and apoptosis in other cell types, we sought to determine if testosterone modulates CSMC proliferation and/or apoptosis through PKCδ. Porcine CSMC cultures (passages 2–6) from castrated males were treated with testosterone for 24 h. Testosterone (20 and 100 nM) decreased [3H]thymidine incorporation in proliferating CSMC to 59 ± 5.3 and 33.1 ± 4.5% of control. Flow cytometric analysis demonstrated that testosterone induced G1arrest in CSMC with a concomitant reduction in the S phase cells. Testosterone reduced protein levels of cyclins D1and E and phosphorylation of retinoblastoma protein while elevating levels of p21cip1and p27kip1. There were no significant differences in the levels of cyclins D3, CDK2, CDK4, or CDK6. Testosterone significantly reduced kinase activity of CDK2 and -6, but not CDK4, -7, or -1. PKCδ small interfering RNA (siRNA) prevented testosterone-mediated G1arrest, p21cip1upregulation, and cyclin D1and E downregulation. Furthermore, testosterone increased CSMC apoptosis in a dose-dependent manner, which was blocked by either PKCδ siRNA or caspase 3 inhibition. These findings demonstrate that the anti-proliferative, pro-apoptotic effects of testosterone on CSMCs are substantially mediated by PKCδ.

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.

Effects of transdermal estrogen on levels of lipids, lipase activity, and inflammatory markers in men with prostate cancer

Androgen deprivation therapy (ADT) for prostate cancer is now used in earlier disease stages and as adjuvant treatment. Recognizing and reducing the toxicity of this therapy, including worsened lipid levels and cardiovascular disease (CVD) risks, has become an important clinical concern. Oral estrogen therapy induces hypogonadism and mitigates many side effects of ADT, but has a high thrombosis risk. Transdermal estrogen therapy (TDE) has a lower thrombosis risk than oral estrogen and may improve CVD risk compared with ADT. This prospective pilot study of 18 men with androgen-independent prostate cancer receiving ADT measured effects of TDE on lipid and inflammatory CVD risk factors before and after 8 weeks of TDE (estradiol 0.6 mg/day). During treatment, estradiol levels rose 17-fold; total cholesterol, LDL cholesterol, and apolipoprotein B levels decreased. HDL2 cholesterol increased, with no changes in triglyceride or VLDL cholesterol levels. Dense LDL cholesterol decreased and LDL buoyancy increased in association with a decrease in HL activity. Highly sensitive C-reactive protein levels and other inflammatory markers did not worsen. Compared with ADT, short-term TDE therapy of prostate cancer improves lipid levels without deterioration of CVD-associated inflammatory markers and may, on longer-term follow-up, improve CVD and mortality rates.

Relationship between androgenic hormones and arterial stiffness, based on longitudinal hormone measurements

Circulating testosterone levels (T) decrease with age in men. Low T has been associated with coronary disease and with risk factors for atherosclerosis. This study examines the relationship in men between androgenic hormones and arterial stiffness, a major risk factor for cardiovascular events. T, sex hormone-binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEAS) were measured longitudinally over 33 yr (follow-up 11.8 +/- 8.3 yr) in 901 men from the Baltimore Longitudinal Study of Aging, of whom 206 (68.1 +/- 13.7 yr) underwent carotid duplex ultrasonography. The 901 men were used to characterize age-associated hormone levels by means of mixed-effects models. Hormone values were estimated for the 206 men at the time of ultrasonography. Free T index (FTI) was calculated by dividing T by SHBG. The arterial stiffness index was calculated from peak systolic and end diastolic diameters of the common carotid artery and simultaneous brachial artery blood pressure. T, FTI, and DHEAS were correlated negatively with age, pulse pressure (PP), and stiffness index (each P < 0.01), whereas SHBG was correlated positively with age and stiffness index (P < 0.01). However, T was the only hormone that predicted the stiffness index after adjustment for age, PP, fasting plasma glucose, body mass index, and total cholesterol. T values 5-10 yr before the carotid study also predicted the stiffness index (P < 0.05). Thus the adverse influence of low T on the cardiovascular system in men may be mediated in part via the effects of T on vascular structure and function.

PTOV1: a novel testosterone-induced atherogenic gene in human aorta

There are gender differences in the development of atherosclerosis, possibly owing to differences in sex steroid hormone action and/or metabolism. One of the atherogenic effects of testosterone is thought to be androgen receptor (AR)-mediated vascular smooth muscle cell (VSMC) proliferation. However, the detailed mechanism of this effect, particularly the identity of the genes associated with VSMC proliferation, remains largely unknown. Therefore, we first employed microarray analysis and, subsequently, quantitative RT-PCR to analyse RNA expression in AR-positive human VSMCs treated with testosterone in order to detect testosterone-induced genes associated with cell proliferation. We further examined whether the genes identified were involved in cell proliferation using small interfering RNA (siRNA) transfection. Expression of the gene products was then evaluated in human aorta with various degrees of atherosclerosis in order to evaluate the clinical relevance of the findings. Both microarray and quantitative RT-PCR analyses demonstrated marked induction of the human prostate overexpressed protein 1 (PTOV1) gene by testosterone in the cell lines: this gene was recently identified as a novel androgen-induced gene involved in prostate tumour cell proliferation. Inhibition of PTOV1 by transfection of its corresponding siRNA suppressed testosterone-induced cell proliferation. In human aorta, PTOV1 immunoreactivity in the nuclei of neointimal VSMCs was abundantly detected in male aorta with mild atherosclerotic changes compared with female aorta or male aorta with severe atherosclerotic changes. These findings indicate that the PTOV1 gene is androgen-responsive in VSMCs and that it may play an important role in androgen-related atherogenesis in the human aorta, particularly early atherosclerosis in the male aorta, through regulating proliferation of neointimal VSMCs.

PKCδ Mediates Testosterone-induced Increases in Coronary Smooth Muscle Cav1.2

Sex hormones have emerged as important modulators of cardiovascular physiology and pathophysiology. Our previous studies demonstrated that testosterone increases expression and activity of L-type, voltage-gated calcium channels (Cav1.2) in coronary arteries of males. The purpose of the present study was to determine whether testosterone (T) alters coronary protein kinase C delta (PKCdelta) expression and whether PKCdelta plays a role in coronary Cav1.2 expression. For in vitro studies, porcine right coronary arteries (RCA) and post-confluent (passages 3-6) 5-day, serum-restricted coronary smooth muscle cell cultures (CSMC) were incubated in the presence and absence of T or dihydrotestosterone (10 and 100 nm) for 18 h at 37 degrees C in a humidified chamber. For sex and endogenous testosterone-dependent effects, RCA were obtained from intact males, castrated males, castrated males with T replacement, and intact females. In vitro T and dihydrotestosterone caused an approximately 2-3-fold increase in PKCdelta protein levels, approximately 1.5-2-fold increase in PKCdelta kinase activity, and localization of PKCdelta toward the plasma membrane and nuclear envelope. PKCdelta protein levels were higher in coronary arteries of intact males compared with intact females. Elimination of endogenous testosterone by castration reduced RCA PKCdelta protein levels, an effect partially (approximately 45%) reversed by exogenous T (castrated males with T replacement). In CSMC, PKC inhibition with either the general PKC inhibitor, cheylerythrine, or the putative PKCdelta inhibitor, rottlerin, completely inhibited the T-mediated increase in coronary Cav1.2 protein levels. Conversely, Go6976, a conventional PKC isoform inhibitor, failed to inhibit T-induced increases in coronary Cav1.2 protein levels. PKCdelta short interference RNA completely blocked T-induced increases in Cav1.2 protein levels in CSMC. These results demonstrate for the first time that 1) endogenous T is a primary modulator of coronary PKCdelta protein and activity in males and 2) T increases Cav1.2 protein expression in a PKCdelta-dependent manner.

Serum dehydroepiandrosterone sulfate concentration and carotid atherosclerosis in men with type 2 diabetes

Decreased serum dehydroepiandrosterone (DHEA) concentrations may be associated with an increased risk of cardiovascular disease (CVD) in men. We evaluated relationships between serum DHEA sulfate (DHEA-S) concentration and carotid atherosclerosis, as well as major cardiovascular risk factors, in men with type 2 diabetes. Serum DHEA-S concentrations were measured in 206 consecutive men with type 2 diabetes. Relationships were analyzed between serum DHEA-S concentration and carotid atherosclerosis, determined by ultrasonographically evaluated intima-media thickness (IMT) and plaque score (PS), as well as major cardiovascular risk factors, including age, blood pressure, and lipid concentrations. Negative correlations were found between DHEA-S concentration and IMT (r = -0.298, P < 0.0001) and between DHEA-S concentration and PS (r = -0.308, P < 0.0001). IMT and PS were significantly greater in patients with lower concentrations of DHEA-S (<1000 ng/ml) than in patients with higher concentrations of DHEA-S (1.07+/-0.30 mm versus 0.91+/-0.19 mm, P < 0.0001, and 5.5+/-4.2 versus 3.1+/-3.4, P < 0.0001, respectively). A negative correlation was found between serum DHEA-S concentration and age (r = -0.488, P < 0.0001). Multiple regression analysis demonstrated that serum DHEA-S concentration was an independent determinant of IMT (beta = -0.289, P < 0.0001) and of PS (beta = -0.301, P < 0.0001). In conclusion, serum DHEA-S concentration is negatively associated with carotid atherosclerosis determined by ultrasonographically evaluated IMT and PS in men with type 2 diabetes.

The effects of short term (3 weeks) testosterone treatment on serum inflammatory markers in men undergoing coronary artery stenting

OBJECTIVE

Inflammation markers can predict restenosis after successful intracoronary stenting. There is evidence that testosterone suppresses the expression of the inflammatory cytokines. We hypothesized that testosterone therapy after coronary stenting can reduce the inflammation markers.

METHODS

We selected 41 men with coronary artery disease who underwent successful stent implantation for a >70% diameter stenosis of a major coronary artery. Patients, who had stable angina and positive exercise test results, were recruited after diagnostic coronary angiography. Twenty-five men were treated with 3 doses of i.m. testosterone administration once a week for 3 weeks following diagnostic angiography. Sixteen patients were recruited as a control group and they received standard therapy. First venous blood samples were obtained after angiography. Stents were implanted 3 weeks after diagnostic angiography. Second venous blood samples were taken 24 h after the coronary stenting.

RESULTS

Baseline biochemical or hematological parameters were similar between the control and treatment groups. After coronary stenting, free testosterone, total testosterone, and sex hormone binding globulin were significantly elevated in the testosterone group (P<0.0001, P<0.0001 and P=0.02; respectively). After coronary stent implantation, there was a significant increase in IL-6 and CRP levels in the control group only (P=0.02 and P=0.038), while TNF-alpha levels were increased significantly in both groups (P=0.016 and P=0.014; respectively). Statistical analysis revealed that testosterone treatment prior to stent implantation attenuated IL-6 and hs-CRP levels significantly (P=0.042 and P=0.043; respectively).

CONCLUSIONS

The present study shows that 3 weeks testosterone treatment prior to intracoronary stenting results in a significant suppression in hs-CRP and IL-6 levels after the stent implantation.

The CAG Repeat Polymorphism in the Androgen Receptor Gene Is Associated with HDL-Cholesterol but Not with Coronary Atherosclerosis or Myocardial Infarction

Background: Age-adjusted morbidity and mortality rates from coronary heart disease (CHD) are higher in men than in women. Androgens are suspected to be responsible for the male disadvantage. The genomic effect of androgens is mediated by the androgen receptor (AR), which has a polymorphic CAG repeat in exon 1. The number of repeats is inversely related to the transcriptional activity of the AR on target genes.

Methods: We investigated the association of this CAG repeat polymorphism with CHD and myocardial infarction (MI) in 2 independent case–control studies involving 544 Caucasian men.

Results: The number of CAG repeats in the AR gene correlated significantly with HDL-cholesterol (HDL-C) in controls (r = 0.21; P = 0.015). This effect was independent of triglycerides, body mass index, alcohol intake, smoking, and age in a multiple regression model (R2 = 50%). Despite decreased HDL-C, lower CAG repeat numbers were not associated with increased risk for CHD (odds ratio = 0.82; 95% confidence interval, 0.50–1.36; P = 0.44) or MI in carriers of AR genes with lower CAG repeat numbers (odds ratio = 0.72; 95% confidence interval, 0.37–1.39; P = 0.33).

Conclusions: Shorter, more androgenic AR alleles with fewer CAG repeats are associated with lower HDL-C, but not with an increased risk for CHD or MI, which argues against a detrimental androgen effect on cardiovascular risk under physiologic conditions.

Increased carotid atherosclerosis in andropausal middle-aged men

OBJECTIVES

This study examined the association between carotid artery intima-media thickness (IMT), serum sex hormone levels, and andropausal symptoms in middle-aged men.

BACKGROUND

Male sex hormones may play a dual role in the pathogenesis of atherosclerosis in men by carrying both proatherogenic and atheroprotective effects.

METHODS

We studied 239 40- to 70-year-old men (mean +/- SD: 57 +/- 8 years) who participated in the Turku Aging Male Study and underwent serum lipid and sex hormone measurements. Ninety-nine men (age 58 +/- 7 years) were considered andropausal (i.e., serum testosterone <9.8 nmol/l or luteinizing hormone [LH] >6.0 U/l and testosterone in the normal range), and in both situations, they had subjective symptoms of andropause (a high symptom score in questionnaire). Three were excluded because of diabetes. The rest of the men (age 57 +/- 8 years) served as controls. Carotid IMT was determined using high-resolution B-mode ultrasound, and serum testosterone, estradiol (E2), LH, and sex hormone-binding globulin were measured using standard immunoassays.

RESULTS

Andropausal men had a higher maximal IMT compared with controls in the common carotid (1.08 +/- 0.34 vs. 1.00 +/- 0.23, p < 0.05) and in the carotid bulb (1.44 +/- 0.48 vs. 1.27 +/- 0.35, p = 0.003). Common carotid IMT correlated inversely with serum testosterone (p = 0.003) and directly with LH (p = 0.006) in multivariate models adjusted for age, total cholesterol, body mass index, blood pressure, and smoking.

CONCLUSIONS

Middle-aged men with symptoms of andropause, together with absolute or compensated (as reflected by high normal to elevated LH) testosterone deficiency, show increased carotid IMT. These data suggest that normal testosterone levels may offer protection against the development of atherosclerosis in middle-aged men.

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

OBJECTIVE

In women, sex hormones cause increased morbidity and mortality in patients with coronary heart disease (CHD) and adversely affect the coagulation profile. We have studied the effect of physiological testosterone replacement therapy in men on coagulation factor expression, to determine if there is an increased risk of thrombosis.

METHODS

Double-blind, randomized, placebo-controlled trial of testosterone in 46 men with chronic stable angina. Measurements of free, total and bioavailable testosterone, luteinising hormone (LH) and follicle-stimulating hormone (FSH), estradiol, plasminogen activator inhibitor-1 (PAI-1), fibrinogen, tissue plasminogen activator (tPA) and full blood count were made at 0, 6 and 14 weeks.

RESULTS

Bioavailable testosterone levels were: 2.58 +/- 0.58 nmol/l at baseline, compared with 3.35 +/- 0.31 nmol/l at week 14 (P < 0.001) after treatment compared with 2.6 +/- 0.18 nmol/l and 2.44 +/- 0.18 nmol/l in the placebo group (P was not significant). There was no change in fibrinogen (3.03 +/- 0.18 g/l at baseline and 3.02 +/- 0.18 g/l at week 14, P = 0.24), tPA activity (26.77 +/- 4.9 Iu/ml and 25.67 +/- 4.4 Iu/ml, P = 0.88) or PAI-1 activity (0.49 +/- 0.85 Iu/ml and 0.36 +/- 0.06 Iu/ml, P = 0.16) with active treatment and no differences between the groups (at week 14, P value 0.98, 0.59 and 0.8 for fibrinogen, PAI-1 and tPA respectively). Haemoglobin concentration did not change over time, in the testosterone group (1.44 +/- 0.02 g/l and 1.45 +/- 0.02 g/l, P = 0.22).

CONCLUSION

Physiological testosterone replacement does not adversely affect blood coagulation status.

Endogenous sex hormones and progression of carotid atherosclerosis in elderly men

BACKGROUND

The burden of atherosclerosis especially afflicts the increasing older segment of the population. Recent evidence has emphasized a protective role of endogenous sex hormones in the development of atherosclerosis in aging men.

METHODS AND RESULTS

We studied the association between endogenous sex hormones and progression of atherosclerosis in 195 independently living elderly men. Participants underwent measurements of carotid intima-media thickness (IMT) at baseline in 1996 and again in 2000. At baseline, serum concentrations of testosterone (total and free) and estradiol (total and free E2) were measured. Serum free testosterone concentrations were inversely related to the mean progression of IMT of the common carotid artery after adjustment for age (beta=-3.57; 95% CI, -6.34 to -0.80). Higher serum total and free E2 levels were related to progression of IMT of the common carotid artery after adjustment for age (beta=0.38; 95% CI, -0.11 to 0.86; and beta=0.018; 95% CI, -0.002 to 0.038, respectively). These associations were independent of body mass index, waist-to-hip ratio, presence of hypertension and diabetes, smoking, and serum cholesterol levels

CONCLUSIONS

Low free testosterone levels were related to IMT of the common carotid artery in elderly men independently of cardiovascular risk factors.

Testosterone metabolism, dose-response relationships and receptor polymorphisms: selected pharmacological/toxicological considerations on benefits versus risks of testosterone therapy in men

In this review selected toxicological problems related to testosterone therapy in hypogonadal men are discussed. Applying "classical" pharmacological/toxicological findings (e.g. animal studies on short- and long-term toxicity) to clinical situations is not very helpful. Molecular biological knowledge and especially evaluation of epidemiological studies, as well as intervention studies, on testosterone therapy in hypogonadal men are more useful. Potential risks include overdosage for lifestyle reasons, e.g. excessive muscle building and reduction of visceral obesity, when erythrocytosis occurs concomitantly. Modern galenic formulations of testosterone administration (e.g. transdermal gel, suitable testosterone esters for intramuscular application and newer oral preparations) avoid supraphysiological serum concentrations, therefore significantly reducing the toxicological risk. A hypothetical model of the toxicological risks of testosterone therapy is given that is based on the influence of testosterone metabolism (aromatization vs. reduction) of the respective parameter/target chosen. Finally, the great influence of polymorphisms of the androgen receptor on the assessment of toxicological risk and on the individualization of androgen therapy is shown. Already existing national, continental and international guidelines or recommendations for the testosterone therapy should be harmonized.