Testosterone and cardiovascular disease: An old idea with modern clinical implications

Elevated circulating follicle stimulating hormone level is associated with dyslipidemia in male type 2 diabetes mellitus patients: A cross-sectional study

AIMS

Type 2 diabetes mellitus (T2DM) commonly combines with dyslipidemia, and both are known as the risk factors of cardiovascular events and aggravate the arteriosclerosis progression. In this study, we investigated the relationship between follicle-stimulating hormone (FSH) and lipid profiles in male T2DM patients.

MATERIALS AND METHODS

We collected clinical data of male T2DM patients in the Chinese Han population hospitalised from January 2018 to June 2020. A total of 963 patients with a mean age of 58.89 ± 12.25 years old were enroled in this study.

RESULTS

The results showed that the levels of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL)-C levels were decreased gradually from the highest quartile groups (Q4) to Q1 group relevant to luteinising hormone and FSH, and no significant difference was observed in high-density lipoprotein-C levels among Q4-Q1 groups. Sub-groups analysis showed that, with the increased FSH level, TC, TG, and LDL-C levels were increased in the elder group (40-59 years old) than those in the younger group (20-39 years old). Spearman's analysis revealed a positive correlation between FSH and the levels of TC, TG, and LDL-C (r = 0.354, r = 0.336, r = 0.312, p < 0.001, respectively). The effect of FSH is independent of the changes in total testosterone level. Multivariate analysis found that increased FSH levels (≥9.26 mIU/mL) and decreased total testosterone levels (<13.30 nmol/L) were positively correlated with high TC, TG, and LDL-Cemia (OR = 4.014, 1.565, 1.602, 1.660, 2.127, 1.322, respectively, p < 0.05).

CONCLUSIONS

Our data suggest that high serum FSH level in male T2DM patients could be a potential independent risk factor correlated with the elevated TC, TG, and LDL-C.

Effect of Testosterone Undecanoate on Sexual Functions, Glycaemic Parameters, and Cardiovascular Risk Factors in Hpogonadal Men with Type 2 Diabetes Mellitus

Aims

To study the effect of testosterone undecanoate on sexual functions, glycaemic parameters, and cardiovascular (CV) risk factors in hypogonadal men with type 2 diabetes mellitus (T2DM).

Methods

It was an open label, single-arm interventional study where testosterone undecanoate (TU) was used in 105 T2DM males aged 30-60 years with hypogonadism. The effect of TU on sexual functions was assessed using the Aging Male Symptoms (AMS) Scale and the International Index of Erectile Function-5 (IIEF-5) Questionnaire. The effect on glycaemic parameters, cardiovascular risk factors (lipids, high-sensitivity C-reactive protein [hsCRP] and carotid intima media thickness [CIMT]) were assessed over a period of 54 weeks of TU therapy.

Results

Prevalence of hypogonadism in T2DM patients was 19.1%, of which 74.1% had functional hypogonadism. AMS and IIEF-5 scores showed negative and positive correlation, respectively, with baseline serum testosterone levels. The AMS score showed a significant reduction of 5.8% and IIEF-5 score improved by 31.5% at 54 weeks of TU therapy. Glycosylated hemoglobin (HbA1c), homeostatic model assessment for insulin resistance (HOMA-IR), and lipids such as total cholesterol (TC), low-density lipoprotein (LDL), and triglycerides (TG) were significantly reduced by 0.6%, 10.9%, 6.28%, 9.04%, and 6.77%, respectively, at 54 weeks. CIMT was significantly reduced by 2.57% at 54 weeks, whereas no significant change observed with hsCRP.

Conclusions

TU is an effective treatment modality for hypogonadal men with T2DM, and it has beneficial effects on sexual functions, glycaemic parameters, and CV risk factors.

The occurrence of hypogonadotropic hypogonadism in Chinese men with type 2 diabetes

CONTEXT

The previous studies showed that hypogonadotropic hypogonadism (HH) occurred commonly in men with type 2 diabetes. However, since all the cohorts tested were from American and European studies, the occurrence of HH/nongonadal illness (NGI) in Chinese populations is unclear.

OBJECTIVE

The study aimed to explore the occurrence of HH/NGI in Chinese men with type 2 diabetes. Furthermore, the correlative factors and predictors of hypogonadism were investigated.

DESIGN

We conducted a cross-sectional study of 637 Chinese men with type 2 diabetes aged 20-75 years in our clinic. The prevalence of HH/NGI was investigated by measuring serum total testosterone (TT), sex hormone-binding globulin (SHBG), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the enrolled subjects. Free testosterone (FT) was calculated by using SHBG and TT levels and hypogonadism was defined as TT lower than 10.4 nmol/L and calculated FT (cFT) lower than 0.225 nmol/L. The LH cut-off value for defining HH/NGI was 9.4 mIU/ml.

RESULTS

The results suggested that 31.9% of male Chinese type 2 diabetes patients had hypogonadism and 26.5% of subjects in our cohort were determined as HH/NGI. The occurrence of hypogonadism was markedly correlated with body mass index (BMI). There was a significant association between TT, cFT and SHBG levels with BMI. TT levels are inversely correlated with BMI and homeostasis model assessment-estimated insulin resistance (HOMA-IR) while positively related with SHBG. The cFT levels were inversely correlated with age, LH, FSH, BMI and HOMA-IR. Multiple regression analysis suggested that SHBG, BMI and HOMA-IR were significant predictors of TT and cFT.

CONCLUSION

Our present study offered the first evidence that the occurrence of HH/NGI in Chinese male type 2 diabetes was 26.5%. TT and cFT were significantly correlated with BMI, SHBG and HOMA-IR in Chinese men with type 2 diabetes.

Serum 25(OH)D Levels Modify the Association between Triglyceride and IR: A Cross-Sectional Study

BACKGROUND

Triglycerides and 25(OH)D had been reported as correlates of IR, but the results suggest substantial heterogeneity across races. In addition, little research reported on whether different 25(OH)D levels affect triglycerides and IR. Therefore, a similar study on the US population would be a great addition to the current one. This study investigated the association between triglycerides and IR at different 25(OH)D levels.

METHODS

A total of 19,926 participants were included, each containing specific indicators for the study project. IR was estimated as a HOMA-IR index ≥2.73. Four multivariate logistic regression models were developed to analyze the association between TG and IR and whether different 25(OH)D levels influenced this association. Smoothed fitting curves were plotted.

RESULTS

Triglyceride was significantly associated with IR (OR: 1.3, 95 CI %), while this association received different 25(OH)D levels (P for interaction <0.001). The effect value OR was 1.33 with the high levels, and its effect value OR was 1.28 with the low levels.

CONCLUSION

This study demonstrates that triglyceride levels are significantly associated with insulin in the US adult population and can be used as a predictor of IR. This correlation was compromised at different 25 (OH)D levels, so future studies need to be explored in more ethnically diverse contexts.

Association between Urinary Triclosan and Serum Testosterone Levels in U.S. Adult Males from NHANES, 2011-2012

Triclosan was introduced into the market in the 1970s and has since been used as an antimicrobial agent in a diverse array of consumer and personal care products. Although it has been widely used over a number of years, there is growing concern and debate over its safety and efficacy and its potential as an endocrine disruptor. Although prior animal toxicology studies have shown an association between triclosan and decreased testosterone levels, human studies have been limited, particularly for adult men. Using the National Health and Nutrition Examination Survey data (NHANES, 2011-2012), we examined the association of urinary triclosan on testosterone levels in adult men 18-65 years of age. Multivariable linear regression analysis failed to show an association between triclosan and serum testosterone (β = 0.0003, p = 0.98, 95% CI = -0.024, 0.025). The results suggest there is no association or that triclosan concentrations are too low to cause a significant impact on testosterone levels. Additionally, longitudinal studies would provide a more comprehensive understanding of the direction of change and magnitude of causal relationships over time.

Metabolic Effects of Testosterone Replacement Therapy in Patients with Type 2 Diabetes Mellitus or Metabolic Syndrome: A Meta-Analysis

BACKGROUND

Testosterone replacement therapy (TRT) is commonly used for the treatment of hypogonadism in men, which is often associated with type 2 diabetes mellitus (T2DM) and metabolic syndrome (Mets). Recent compiling evidence shows that TRT has beneficial metabolic effects on these patients.

OBJECTIVE

A meta-analysis has been conducted to evaluate the effects of TRT on cardiovascular metabolic factors.

METHODS

We conducted a systemic search on PubMed, Embase, Cochrane Library, Wanfang, and CNKI and selected randomized controlled trials (RCTs) to include. The efficacy of TRT on glycemia, insulin sensitivity, lipid profile, and body weight was meta-analyzed by Review Manager.

RESULTS

A total of 18 RCTs, containing 1415 patients (767 in TRT and 648 in control), were enrolled for the meta-analysis. The results showed that TRT could reduce HbA1c (MD = -0.67, 95% CI -1.35, -0.19, and P=0.006) and improve HOMA-IR (homeostatic model assessment of insulin resistance) (SMD = -1.94, 95% CI -2.65, -1.23, and P < 0.0001). TRT could also decrease low-density lipoprotein (SMD = -0.50, 95% CI -0.82, -0.90, and P=0.002) and triglycerides (MD = -0.64, 95% CI -0.91, -0.36, and P < 0.0001). In addition, TRT could reduce body weight by 3.91 kg (MD = -3.91, 95% CI -4.14, -3.69, and P < 0.00001) and waist circumference by 2.8 cm (MD -2.80, 95% CI -4.38, -1.21 and P=0.0005). Erectile dysfunction (measured by IIEF-5) did not improve, while aging-related symptoms (measured by AMS scores) significantly improved.

CONCLUSIONS

TRT improves glycemic control, insulin sensitivity, and lipid parameters in hypogonadism patients with T2DM and MetS, partially through reducing central obesity.

Circadian rhythm disorder: a potential inducer of vascular calcification?

Over the past decades, circadian rhythm has drawn a great attention in cardiovascular diseases. The expressions of rhythm genes fluctuate in accordance with the diurnal changes of vascular physiology, which highlights the pivotal effect of vascular clock. Recent researches show that the circadian clock can directly regulate the synthetic and secretory function of endothelial cells and phenotypic switch of vascular smooth muscle cells to adjust vascular relaxation and contraction. Importantly, dysfunction of vascular cells is involved in vascular calcification. Secretion of osteogenic cytokines and calcified vesicles in the vessel, osteogenic phenotype switch of vascular smooth muscle cells are all implicated in the calcification process. Moreover, circadian rhythm disorder can lead to abnormal hormone secretion, oxidative stress, inflammatory reaction, and autophagy, all of which should not be ignored in vascular calcification. Vascular senescence is another pathogenetic mechanism in vascular calcification. Accelerated vascular senescence may act as an important intermediate factor to promote vascular calcification in circadian rhythm disorders. In this review, we elaborate the potential effect of circadian rhythm disorder in vascular calcification and try to provide a new direction in the prevention of vascular calcification.

Sexual dysfunction and central obesity in patients with first episode psychosis

Background

In recent years the association between sexual dysfunction (SD) and obesity in the general population has drawn major attention. Although sexual dysfunction is common in psychosis, its relationship with weight gain and obesity remains unclear.

Aims

To investigate the association between sexual dysfunction and obesity in a cohort of patients with first episode psychosis.

Method

Sexual function was assessed in a cohort of patients with first episode psychosis using the Sexual Function Questionnaire (SFQ). Anthropometric measures, including weight, BMI, waist, waist–hip ratio were investigated. Additionally, leptin and testosterone were investigated in male patients.

Results

A total of 116 patients (61 males and 55 females) were included. Of these 59% of males and 67.3% of females showed sexual dysfunction (SD) according to the SFQ. In males, higher SFQ scores were significantly correlated with higher BMI (Std. β = 0.36, P = 0.01), higher leptin levels (Std. β = 0.34, P = 0.02), higher waist–hip ratio (Std. β = 0.32, P = 0.04) and lower testosterone levels (Std. β = −0.44, P = 0.002). In contrast, in females, SFQ scores were not associated with any of these factors.

Conclusions

While sexual dysfunction is present in both female and male patients with their first episode of psychosis, only in males is sexual dysfunction associated with increased BMI and waist–hip ratio. The association between SD, BMI, low levels of testosterone and high levels of leptin suggest that policies that lead to healthier diets and more active lifestyles can be beneficial at least, to male patients.

Vascular mechanisms of testosterone: The non-genomic point of view

Testosterone (T) is the predominant endogenous androgen in the bloodstream. At the vascular level, T presents genomic and non-genomic effects, and both effects may overlap. The genomic actions assume that androgens can freely cross the plasma membrane of target cells and bind to nuclear androgen receptors, inducing gene transcription and protein synthesis. The non-genomic effects have a more rapid onset and may be related to the interaction with protein/receptor/ion channels of the plasma membrane. The key T effect at the vascular level is vasorelaxation, which is primarily due to its rapid effect. Thus, the main purpose of this review is to discuss the T non-genomic effects at the vascular level and the molecular pathways involved in its vasodilator effect observed in in vivo and in vitro studies. In this sense, the nuclear receptor activation, the influence of vascular endothelium and the activation or inhibition of ion channels (potassium and calcium channels, respectively) will be reviewed regarding all the data that corroborated or not. Moreover, this review also provides a brief update on the association of T with the risk factors for cardiovascular diseases, namely metabolic syndrome, type 2 diabetes mellitus, obesity, atherosclerosis, dyslipidaemia, and hypertension. In summary, in this paper we consider the non-genomic vascular mode of action of androgen in physiological conditions and the main risk factors for cardiovascular diseases.

The Role of Diet and Weight Loss in Improving Secondary Hypogonadism in Men with Obesity with or without Type 2 Diabetes Mellitus

Despite growing recognition of the issue, obesity represents one of the most common public health problems, and its rates are still increasing globally. Among the number of comorbidities and complications associated with obesity, hypogonadism is listed, and this disorder, although frequently neglected, is characterized by a relevant impact on both quality of life and life expectancy. It is generally accepted that hypogonadism secondary to obesity is functional since it is reversible following weight loss. This review summarizes all current research examining the bidirectional relationship between excess body weight and low testosterone levels. Specifically, it evaluates the role that diet, with or without physical activity, plays in improving body weight and hypogonadism in adult and elderly men with obesity, with or without type 2 diabetes mellitus.

African star apple fruit pulp-supplemented diet modulates fertility-related biomolecules in the testis and epididymis of high-fat diet/streptozotocin-induced diabetic rats

This study evaluated the modulatory effect of African star apple fruit (ASAF) pulp inclusive diet on biomolecules associated with reproductive function in the testis and epididymis of high-fat diet/streptozotocin-induced diabetic male rats. The rats were divided into seven groups: control, diabetic control, diabetic rats treated with metformin, diabetic rats served with diet having 5 and 10% ASAF, respectively, and control rats served with diet containing 5%, and 10% ASAF respectively for 14 days. There were noticeable decrease in sperm parameters, reproductive hormone, glycogen, nitric oxide, total thiol, nonprotein thiol levels, and testicular 3β- and 17β-hydroxysteroid dehydrogenase activities and concomitant increase in cholesterol, reactive oxygen species, malondialdehyde levels, and arginase activity compared to the control. Nevertheless, ASAFs reversed all these parameters toward the control levels. Therefore, these findings suggest that ASAF pulp-supplemented diet might be an active approach in controlling male reproductive dysfunction induced by diabetes. PRACTICAL APPLICATIONS: The results suggest that ASAF pulp-supplemented diet might be an active approach in controlling male reproductive dysfunction induced by diabetes through alterations in the levels of blood glucose, glycogen, cholesterol, nitric oxide, reproductive hormones, activities of steroidogenic enzymes, arginase, and sperm characteristics as well as the antioxidant status in the testes and epididymis.

Androgens and Blood Pressure Control: Sex Differences and Mechanisms

The role that androgens play in mediating elevated blood pressure is unclear. Low levels of androgens in men and increased levels of androgens in women, as occurs with polycystic ovary syndrome (PCOS), are both associated with increased risk for cardiovascular disease and elevated blood pressure. We have used animal models to evaluate the potential mechanisms by which men and women have differential responses to androgens that affect regulation of blood pressure and the implications these may have for the health of men and women.

Walnut leaf extract acts as a fertility agent in male Wistar albino rats - A search for herbal male fertility enhancer

Background Walnut leaf is one of the many medicinal plants used in folklore as male fertility enhancers. The present work was therefore undertaken with an aim to scientifically validate this claim. As such, we evaluated the effect of the aqueous extract from walnut leaves on biomolecules related to fertility in adult male rats and its mode of action as fertility-enhancing agent. Methods Twenty-five rats were randomly divided into five groups of five animals each; Group 1 served as control and received normal (0.9%) saline only; Groups II, III, IV received 50, 500, 1,000 mg/kg body weight (BW) of T. conophorum leaf extract orally, while Group V served as standard and was given suspension of clomiphene citrate orally at the dose of 1.04 mg/kg/ml BW. The extract and drug were given daily and the experiment lasted for 21 consecutive days. Results The testicular biochemical parameters in treated groups showed significant (p<0.05) increase in lactate dehydrogenase activity activity, Glucose-6-phosphate dehydrogenase (G-6PDH) activity, glycogen content, 3β and 17β hydroxysteroid dehydrogenase activities and testicular and epididymal Zn and Se contents with a significant decrease in cholesterol content. A significant increase in testis weight and epididymis weight were also observed. Also, a significant (p<0.05) increase in the level of serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone, sperm count, motility, viability and a decrease in sperm abnormality were observed in the various treated groups when compared with the control group. This increment was concentration dependent, while the extract at the highest concentration showed a more pronounced effect than the standard drug. Also, no sperm DNA fragmentation index was found in all the treatment groups. Photomicrographs from light and scanning electron microscopy showed large fenestrae of interstitial tissue, large fluid space and intact seminiferous epithelium layers fully packed with spermatogenic cells in treated groups than the control group. Conclusions The present study has demonstrated that Tetracarpidium conophorum leaf possesses fertility-enhancing property and have useful effects on spermatogenesis and sperm parameters in rats.

Translational Perspective on the Role of Testosterone in Sexual Function and Dysfunction

INTRODUCTION

The biological importance of testosterone is generally accepted by the medical community; however, controversy focuses on its relevance to sexual function and the sexual response, and our understanding of the extent of its role in this area is evolving.

AIM

To provide scientific evidence examining the role of testosterone at the cellular and molecular levels as it pertains to normal erectile physiology and the development of erectile dysfunction and to assist in guiding successful therapeutic interventions for androgen-dependent sexual dysfunction.

METHODS

In this White Paper, the Basic Science Committee of the Sexual Medicine Society of North America assessed the current basic science literature examining the role of testosterone in sexual function and dysfunction.

RESULTS

Testosterone plays an important role in sexual function through multiple processes: physiologic (stimulates activity of nitric oxide synthase), developmental (establishes and maintains the structural and functional integrity of the penis), neural (development, maintenance, function, and plasticity of the cavernous nerve and pelvic ganglia), therapeutically for dysfunctional regulation (beneficial effect on aging, diabetes, and prostatectomy), and phosphodiesterase type 5 inhibition (testosterone supplement to counteract phosphodiesterase type 5 inhibitor resistance).

CONCLUSION

Despite controversies concerning testosterone with regard to sexual function, basic science studies provide incontrovertible evidence for a significant role of testosterone in sexual function and suggest that properly administered testosterone therapy is potentially advantageous for treating male sexual dysfunction.

Associations of Cardiovascular Risk Factors with Carotid Intima-Media Thickness in Middle-Age Adults and Elders

Aims: Elevated carotid intima-media thickness (cIMT) is a preclinical phenotype of atherosclerotic diseases. There are significant sex differences in the morbidities of cardiovascular diseases and their major determinants, and we explored the sex-specific effects of cardiovascular factors on cIMT by a community-based study.

Methods: We measured the cIMT and cardiovascular profiles of 1579 residents aged 40–74 years in northern Taiwan. Multivariate regression analyses were used to assess the effects and contributions of these factors on cIMT.

Results: Males had significantly higher mean (± SD) of cIMT than females (0.668 ± 0.113 vs. 0.632 ± 0.100 nm, p < 0.0001). The common factors of the best-fit regression models in both sexes were age, BMI, and LDL-/HDL-C ratio; however, their contributions and effects were different. The partial coefficients of determination (r²) were 17.9, 5.8, and 4.1%, respectively, for males and were 27.8, 1.4, and 1.2%, respectively, for females. Test statistics showed that the regression coefficients of BMI and LDL-/HDL-C ratio of males were significantly higher than those of females. As compared with females, per 1.0 SD increases of BMI and LDL-/HDL-C in males resulted in 0.0971 (p = 0.030) and 0.1177 (p = 0.0087), respectively, SD increases in cIMT. There was no difference in the means of cIMT between pre- and post-menopausal women of the same age groups.

Conclusions: There was a significant sex difference in cIMT. The contributions and effects of LDL-/HDL-C ratio and BMI on cIMT were more profound in males. Our findings indicate that sex-specific factors, but possibly not menstrual status-related factors, contribute to thicker cIMT.

Vildagliptin reduces cardiac ischemic-reperfusion injury in obese orchiectomized rats

Obesity and testosterone deprivation are associated with coronary artery disease. Testosterone and vildagliptin (dipeptidyl peptidase-4 inhibitors) exert cardioprotection during ischemic-reperfusion (I/R) injury. However, the effect of these drugs on I/R heart in a testosterone-deprived, obese, insulin-resistant model is unclear. This study investigated the effects of testosterone and vildagliptin on cardiac function, arrhythmias and the infarct size in I/R heart of testosterone-deprived rats with obese insulin resistance. Orchiectomized (O) or sham operated (S) male Wistar rats were divided into 2 groups to receive normal diet (ND) or high-fat diet (HFD) for 12 weeks. Orchiectomized rats in each diet were divided to receive testosterone (2 mg/kg), vildagliptin (3 mg/kg) or the vehicle daily for 4 weeks. Then, I/R was performed by a 30-min left anterior descending coronary artery ligation, followed by a 120-min reperfusion. LV function, arrhythmia scores, infarct size and cardiac mitochondrial function were determined. HFD groups developed insulin resistance at week 12. At week 16, cardiac function was impaired in NDO, HFO and HFS rats, but was restored in all testosterone- and vildagliptin-treated rats. During I/R injury, arrhythmia scores, infarct size and cardiac mitochondrial dysfunction were prominently increased in NDO, HFO and HFS rats, compared with those in NDS rats. Treatment with either testosterone or vildagliptin similarly attenuated these impairments during I/R injury. These finding suggest that both testosterone replacement and vildagliptin share similar efficacy for cardioprotection during I/R injury by decreasing the infarct size and attenuating cardiac mitochondrial dysfunction caused by I/R injury in testosterone-deprived rats with obese insulin resistance.

The Role of Gender in Chronic Kidney Disease

Chronic kidney disease (CKD) is a common disease worldwide and is associated with high rates of morbidity and mortality. This review discusses several aspects of the relationship between gender and CKD. While the prevalence of CKD tends to be higher in women, the disease is more severe in men, who also have a higher prevalence of end-stage renal disease. Most of the evidence in the current literature suggests a higher progression rate and mortality risk of CKD in men compared with women, except in post-menopausal women and diabetic patients. However, the decrease in glomerular filtration rate and the increase in the level of albuminuria are more prominent mortality risk factors among women. Sex hormones are thought to play a major role in the biological mechanisms associated with variability in CKD prevalence and characteristics between men and women. Animal studies have demonstrated the harmful influence of testosterone and protective influence of oestrogen on several biological processes that are involved in kidney injury. However, the role of sex hormones in explaining gender-related differences in CKD in humans has not yet been established. In summary, gender has an important influence on several aspects of CKD. Further research is needed to find additional gender-related characteristics in CKD and to identify the mechanisms of sexual dimorphism in CKD.

Testosterone and gonadotropins but not SHBG vary with CKD stages in young and middle aged men

Background

The aim of this study was to assess the effects chronic kidney disease (CKD) had on sex hormones and lipids in a subgroup of men between 18 and 50 years old with CKD 1–5 stage without diabetes and not treated with hemodialysis.

Methods

Data were collected from 101 men with different CKD stages.

Results

Higher CKD stage (lower function) had a significant negative linear trend on total testosterone level (p < 0.01) and free testosterone level (p < 0.01), with a significant increase of luteinizing hormone (LH) (p < 0.01), and prolactin (p < 0.01), while SHBG remained unchanged between the CKD stages. Triglycerides but not total cholesterol, HDL –cholesterol or LDL-cholesterol increased with higher CKD stage. A negative correlation was observed between BMI, SHBG and free testosterone (p < 0.01 for both) but not with other sex hormones. Age per se was related to a significant decrease of total and free testosterone level (p < 0.01 for both) even after correction for BMI.

Decreased levels of total testosterone and estimated free testosterone levels had a significant correlation with an increased level of triglyceride levels (p <0.01).

Conclusions

Our results indicate that CKD stage per se is a factor affecting testosterone levels in combination with age in men between 18 and 50 years old with CKD 1–5 stage, not treated with hemodialysis.

With increased CKD stage there was a significant increase in LH level and a pattern of hypergonadotropic hypogonadism. SHBG remained unchanged between the CKD stages.

Electronic supplementary material

The online version of this article (doi:10.1186/s12610-015-0027-y) contains supplementary material, which is available to authorized users.

Synergistic Effect of a Physiological Ratio of Estradiol and Testosterone in the Treatment of Early-stage Atherosclerosis

BACKGROUND AND AIMS

Clinical trials and epidemiological data suggest that estrogen replacement therapy (ERT) fails to reduce cardiovascular events in postmenopausal women with coronary heart disease (CHD). The high concentration of estrogen supplementation may increase the risk of thrombosis and result in testosterone deficiency, which is considered the main reason for failure. Thus, we hypothesized that a physiologic dosage of estradiol combined with testosterone may become a new therapeutic strategy in postmenopausal women with CHD.

METHODS AND RESULTS

We used human umbilical vein endothelial cells (HUVECs) and female C57BL/6 mice as the experimental subjects. With the HUVECs, we found an appropriate E2/T ratio of 5:1 (5×10(-8) mol/L estradiol and 10(-8) mol/L testosterone), which has a significant anti-apoptotic effect on HUVECs by inducing a C-reactive protein. In the in vivo study, we verified the beneficial effects of the defined appropriate E2/T ratio in mice with early stage atherosclerosis. We found that replacement therapy with the defined appropriate E2/T ratio had beneficial effects of reducing the lipid lesions, reducing the formation of foam cells, reducing endothelial injury, modulating the coagulation system function and inhibiting inflammation and was significantly more effective than either estradiol or testosterone supplementation alone.

CONCLUSION

The present study demonstrated that estradiol and testosterone have a synergistic effect on early stage atherosclerosis, and replacement therapy with the defined appropriate E2/T ratio can significantly suppress the development of atherosclerosis through reducing the lipid lesions, reducing the formation of foam cells, reducing endothelial injury, modulating the coagulation system function and inhibiting inflammation.

Optimal Prediction of Carotid Intraplaque Hemorrhage Using Clinical and Lumen Imaging Markers

BACKGROUND AND PURPOSE

MR imaging detects intraplaque hemorrhage with high accuracy by using the magnetization-prepared rapid acquisition of gradient echo sequence. Still, MR imaging is not readily available for all patients, and many undergo CTA instead. Our goal was to determine essential clinical and lumen imaging predictors of intraplaque hemorrhage, as indicators of its presence and clues to its pathogenesis.

MATERIALS AND METHODS

In this retrospective cross-sectional study, patients undergoing stroke work-up with MR imaging/MRA underwent carotid intraplaque hemorrhage imaging. We analyzed 726 carotid plaques, excluding vessels with non-carotid stroke sources (n = 420), occlusions (n = 7), or near-occlusions (n = 3). Potential carotid imaging predictors of intraplaque hemorrhage included percentage diameter and millimeter stenosis, plaque thickness, ulceration, and intraluminal thrombus. Clinical predictors were recorded, and a multivariable logistic regression model was fitted. Backward elimination was used to determine essential intraplaque hemorrhage predictors with a thresholded 2-sided P < .10. Receiver operating characteristic analysis was also performed.

RESULTS

Predictors of carotid intraplaque hemorrhage included plaque thickness (OR = 2.20, P < .001), millimeter stenosis (OR = 0.46, P < .001), ulceration (OR = 4.25, P = .020), age (OR = 1.11, P = .001), and male sex (OR = 3.23, P = .077). The final model discriminatory value was excellent (area under the curve = 0.932). This was significantly higher than models using only plaque thickness (area under the curve = 0.881), millimeter stenosis (area under the curve = 0.830), or ulceration (area under the curve= 0.715, P < .001).

CONCLUSIONS

Optimal discrimination of carotid intraplaque hemorrhage requires information on plaque thickness, millimeter stenosis, ulceration, age, and male sex. These factors predict intraplaque hemorrhage with high discriminatory power and may provide clues to the pathogenesis of intraplaque hemorrhage. This model could be used to predict the presence of intraplaque hemorrhage when MR imaging is contraindicated.

Male-Specific Cardiac Dysfunction in CTP:Phosphoethanolamine Cytidylyltransferase (Pcyt2)-Deficient Mice

Phosphatidylethanolamine (PE) is the most abundant inner membrane phospholipid. PE synthesis from ethanolamine and diacylglycerol is regulated primarily by CTP:phosphoethanolamine cytidylyltransferase (Pcyt2). Pcyt2(+/-) mice have reduced PE synthesis and, as a consequence, perturbed glucose and fatty acid metabolism, which gradually leads to the development of hyperlipidemia, obesity, and insulin resistance. Glucose and fatty acid uptake and the corresponding transporters Glut4 and Cd36 are similarly impaired in male and female Pcyt2(+/-) hearts. These mice also have similarly reduced phosphatidylinositol 3-kinase (PI3K)/Akt1 signaling and increased reactive oxygen species (ROS) production in the heart. However, only Pcyt2(+/-) males develop hypertension and cardiac hypertrophy. Pcyt2(+/-) males have upregulated heart AceI expression, heart phospholipids enriched in arachidonic acid and other n-6 polyunsaturated fatty acids, and dramatically increased ROS production in the aorta. In contrast, Pcyt2(+/-) females have unmodified heart phospholipids but have reduced heart triglyceride levels and altered expression of the structural genes Acta (low) and Myh7 (high). These changes together protect Pcyt2(+/-) females from cardiac dysfunction under conditions of reduced glucose and fatty acid uptake and heart insulin resistance. Our data identify Pcyt2 and membrane PE biogenesis as important determinants of gender-specific differences in cardiac lipids and heart function.

Induced testosterone deficiency: from clinical presentation of fatigue, erectile dysfunction and muscle atrophy to insulin resistance and diabetes

Over the past 60 years, androgen deprivation therapy has been the mainstay of treatment of metastatic prostate cancer. However, research findings suggest that androgen deprivation therapy inflicts serious adverse effects on overall health and reduces the quality of life. Among the adverse effects known to date are insulin resistance, diabetes, metabolic syndrome fatigue, erectile dysfunction, and cardiovascular disease. In this clinical perspective, we discuss the relationship between induced androgen deficiency and a host of pathologies in the course of treatment with androgen deprivation therapy for prostate cancer patients.

Androgen deficiency and mitochondrial dysfunction: implications for fatigue, muscle dysfunction, insulin resistance, diabetes, and cardiovascular disease

Among the major physiological functions of steroid hormones is regulation of carbohydrate, fat, and protein metabolism. Mitochondria, through oxidative phosphorylation, play a critical role in modulating a host of complex cellular metabolic pathways to produce chemical energy to meet the metabolic demand for cellular function. Thus, androgens may regulate cellular metabolism and energy production by increased mitochondrial numbers, activation of respiratory chain components, and increased transcription of mitochondrial-encoded respiratory chain genes that code for enzymes responsible for oxidative phosphorylation. Androgen deficiency is associated with increased insulin resistance, type 2 diabetes (T2DM), metabolic syndrome, obesity, and increased overall mortality. One common link among all these pathologies is mitochondrial dysfunction. Contemporary evidence exists suggesting that testosterone deficiency (TD) contributes to mitochondrial dysfunction, including structural alterations and reduced expression and activities of metabolic enzymes. Here, we postulate that TD contributes to symptoms of fatigue, insulin resistance, T2DM, cardiovascular risk, and metabolic syndrome through a common mechanism involving impairment of mitochondrial function.

Chronic testosterone replacement exerts cardioprotection against cardiac ischemia-reperfusion injury by attenuating mitochondrial dysfunction in testosterone-deprived rats

Background

Although testosterone deficiency is associated with increased risks of heart disease, the benefits of testosterone therapy are controversial. Moreover, current understanding on the cardiac effect of testosterone during cardiac ischemia-reperfusion (I/R) periods is unclear. We tested the hypothesis that testosterone replacement attenuates the impairment of left ventricular (LV) function and heart rate variability (HRV), and reduces the infarct size and arrhythmias caused by I/R injury in orchiectomized (ORX) rats.

Methodology

ORX or sham-operated male Wistar rats (n = 24) were randomly divided and received either testosterone (2 mg/kg, subcutaneously administered) or the vehicle for 8 weeks. The ejection fraction (EF) and HRV were determined at baseline and the 4^th and 8^th week. I/R was performed by left anterior descending coronary artery ligation for 30 minutes, followed by a 120-minute reperfusion. LV pressure, arrhythmia scores, infarct size and cardiac mitochondrial function were determined.

Results

Prior to I/R, EF and HRV were impaired in the ORX group, but were restored in the testosterone-treated group. During I/R, arrhythmia scores and the infarct size were greater, and cardiac mitochondrial function was impaired, whereas the time to 1^st VT/VF onset and the LV end-systolic pressure were decreased in the ORX group when compared to the sham group. Testosterone replacement attenuated the impairment of these parameters in ORX rats during I/R injury, but did not show any benefit or adverse effect in non-ORX rats.

Conclusions

Testosterone replacement restores cardiac function and autonomic regulation, and exerts cardioprotective effects during the I/R period via mitochondrial protection in ORX rats.

Effect of testosterone deficiency on cholesterol metabolism in pigs fed a high-fat and high-cholesterol diet

Background

Testosterone deficiency is associated with increased serum cholesterol levels. However, how testosterone deficiency precisely affects cholesterol metabolism remains unclear. Therefore, in the current study, we examined the effect of testosterone deficiency on cholesterol metabolism and liver gene expression in pigs fed a high-fat and high-cholesterol (HFC) diet.

Methods

Sexually mature male miniature pigs (6–7 months old) were randomly divided into 3 groups as follows: intact male pigs fed an HFC diet (IM + HFC), castrated male pigs fed an HFC diet (CM + HFC), and castrated pigs with testosterone replacement fed an HFC diet (CM + HFC + T). Serum testosterone levels and lipid profiles were measured, and gene expression levels associated with hepatic cholesterol metabolism were determined. Furthermore, total hepatic cholesterol contents and the activities of enzymes mediating hepatic cholesterol metabolism were measured.

Results

Serum testosterone levels were significantly decreased in CM + HFC pigs, and testosterone replacement attenuated castration-induced testosterone deficiency. Castration significantly increased the serum levels of total cholesterol, low-density lipoprotein cholesterol and triglycerides, as well as hepatic lipid contents in pigs fed an HFC diet. Compared with IM + HFC and CM + HFC + T pigs, low-density lipoprotein receptor (LDLR) mRNA expression and protein levels were significantly decreased in the livers of CM + HFC pigs. In contrast, we found that compared with IM + HFC pigs, hepatic proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA and serum PCSK9 protein levels were significantly increased in CM + HFC pigs. Moreover, testosterone treatment reversed the increase in PCSK9 expression in CM + HFC pigs. However, neither castration nor testosterone replacement affected the expression of the other hepatic genes that were tested.

Conclusions

This study demonstrated that castration-induced testosterone deficiency caused severe hypercholesterolemia in pigs fed an HFC diet; furthermore, these effects could be reversed by testosterone replacement therapy. Altered hepatic PCSK9 and LDLR expression, resulting in reduced LDL-cholesterol clearance, may contribute to the increased serum cholesterol levels induced by testosterone deficiency and an HFC diet. These results deepen our understanding of the underlying molecular mechanisms that mediate the effects of testosterone deficiency on cholesterol metabolism.

Molecular effects of supraphysiological doses of doping agents on health

Supraphysiological doses of doping agents, such as T/DHT and GH/IGF-1, affect cellular pathways associated with apoptosis and inflammation.

Sex-steroid imbalance in females and dry eye

Dry eye (DE) is a multifactorial disorder of the ocular surface unit that results in eye discomfort, visual disturbance and ocular surface damage. It is one of the most common complaints in daily ophthalmic practice. The risk of DE increases with age in both sexes, while its incidence is higher among females. In addition, the condition of menopause in aging women may also contribute to DE onset or worsening as a consequence of an overall hormonal imbalance. Sex hormones play a key role in ocular surface physiology and they impact differently on ocular surface tissues. Reduced estrogen levels were historically thought to be responsible in age-related DE onset but more recent investigations have reconsidered the role of androgens that are present and exert a protective function on the ocular surface. Hormone levels themselves, withdrawal changes in hormone levels, and the changes in hormone-receptor responsiveness are all important factors but it remains to be fully elucidated how estrogen or androgen insufficiency act alone or together in a combined imbalance or interplay to raise the risk of disease. The purpose of this review is to briefly outline current scientific evidence on the influence of androgens and estrogens, on the Lachrymal and Meibomian glands and on ocular surface epithelia including conjunctival goblet cells during reproductive and menopausal periods. The role of sex steroids is also discussed in relation to the pathogenesis of different forms of DE and Sjogren's syndrome (SS). The impact of systemic hormone therapy (HT) in DE post-menopausal women still appears as a controversial issue, despite the many clinical studies. Finally, the outcomes of topical applications of steroid-based products are summarized, underlying the need for potential (tear) biomarker(s) in the rationale of DE-targeted therapy.

Male hypogonadism and metabolic syndrome

The role of androgens in cardiovascular disease is still controversial in men. In this study, we investigated metabolic disorders in Tunisian hypogonadal men compared with healthy controls. Forty hypogonadal men and 80 control subjects were enrolled. Patients with a history of pre-existing panhypopituitarism, thyroid dysfunction or inflammatory disease were excluded. Glycaemia, glycated haemoglobin (HbA1c), high-sensitive C-reactive protein (hsCRP), lipid profile, insulin, testosterone and gonadotrophins were measured. Insulin resistance was assessed by homoeostasis model assessment of insulin resistance (Homa IR). Waist circumference, body mass index and blood pressure were significantly higher in patients compared with controls. Glycemia, HbA1c, fasting serum insulin and Homa IR were significantly increased among hypogonadal men. In univariate analysis, testosterone levels were inversely correlated with body mass index, waist circumference, blood pressure, glycaemia, HbA1C, insulin, Homa IR and hsCRP. In multivariate analysis including all significant variables, initial testosterone level was the only independent risk factor for developing dyslipidaemia. With logistic regression, male hypogonadism was an independent risk factor for MS (P < 0.001). We conclude that low testosterone level plays a central role in the development of metabolic syndrome. Further prospective data are required to establish the causative link.

Risk of Myocardial Infarction in Older Men Receiving Testosterone Therapy

BACKGROUND

Testosterone therapy for older men has increased substantially over the past decade. Research on the effects of testosterone therapy on cardiovascular outcomes has yielded inconsistent results.

OBJECTIVE

To examine the risk of myocardial infarction (MI) in a population-based cohort of older men receiving intramuscular testosterone.

METHOD

Using a 5% national sample of Medicare beneficiaries, we identified 6355 patients treated with at least 1 injection of testosterone between January 1, 1997, and December 31, 2005. We matched this cohort to 19 065 testosterone nonusers at a 1:3 ratio based on a composite MI prognostic score. Patients were followed until December 31, 2005, or until they lost coverage from Medicare, enrolled in a health maintenance organization, experienced a MI, or died.

RESULT

In a Cox regression analysis adjusting for demographic and clinical characteristics, receipt of testosterone therapy was not associated with an increased risk of MI (hazard ratio [HR] = 0.84; 95% CI = 0.69-1.02). In this analysis, there was an interaction between receipt of testosterone and quartile of risk of MI (P = 0.023). For men in the highest quartile of the MI prognostic score, testosterone therapy was associated with a reduced risk of MI (HR = 0.69; 95% CI = 0.53-0.92), whereas there was no difference in risk for the first (HR = 1.20; 95% CI = 0.88-1.67), second (HR = 0.94; 95% CI = 0.69-1.30), and third quartiles (HR = 0.78; 95% CI = 0.59-1.01).

CONCLUSION

Older men who were treated with intramuscular testosterone did not appear to have an increased risk of MI. For men with high MI risk, testosterone use was modestly protective against MI.

Long-term testosterone therapy in hypogonadal men ameliorates elements of the metabolic syndrome: an observational, long-term registry study

AIM

The goal of this study was to determine if long-term testosterone (T) therapy in men with hypogonadism, henceforth referred to as testosterone deficiency (TD), ameliorates or improves metabolic syndrome (MetS) components.

METHODS

We performed a cumulative registry study of 255 men, aged between 33 and 69 years (mean 58.02 ± 6.30) with subnormal plasma total T levels (mean: 9.93 ± 1.38; range: 5.89-12.13 nmol/l) as well as at least mild symptoms of TD assessed by the Aging Males' symptoms scale. All men received treatment with parenteral T undecanoate 1000 mg (Nebido(®) , Bayer Pharma, Berlin, Germany), administered at baseline and 6 weeks and thereafter every 12 weeks for up to 60 months. Lipids, glucose, liver enzymes and haemoglobin A1c analyses were carried out in a commercial laboratory. Anthropometric measurements were also made throughout the study period.

RESULTS

Testosterone therapy restored physiological T levels and resulted in reductions in total cholesterol (TC) [7.29 ± 1.03 to 4.87 ± 0.29 mmol/l (281.58 ± 39.8 to 188.12 ± 11.31 mg/dl)], low-density lipoprotein cholesterol [4.24 ± 1.07 to 2.84 ± 0.92 mmol/l (163.79 ± 41.44 to 109.84 ± 35.41 mg/dl)], triglycerides [3.14 ± 0.58 to 2.16 ± 0.13 mmol/l (276.16 ± 51.32 to 189.78 ± 11.33 mg/dl)] and increased high-density lipoprotein levels [1.45 ± 0.46 to 1.52 ± 0.45 mmol/l (56.17 ± 17.79 to 58.85 ± 17.51 mg/dl)] (p < 0.0001 for all). There were marked reductions in systolic and diastolic blood pressure, blood glucose, haemoglobin A1c , C-reactive protein (6.29 ± 7.96 to 1.03 ± 1.87 U/l), alanine aminotransferase and aspartate aminotransferase (p < 0.0001 for all).

CONCLUSIONS

Long-term T therapy, at physiological levels, ameliorates MetS components. These findings strongly suggest that T therapy in hypogonadal men may prove useful in reducing the risk of cardiometabolic diseases.

Influence of obesity on blood pressure and arterial stiffness in the early teens

PROBLEM

We studied the influence of adiposis on the progression of blood pressure and arteriosclerosis in the early teens.

METHODS

The subjects of this study were 147 boys and girls (72 boys and 75 girls) in junior high school. Height, weight, percentage body fat, blood pressure, brachial-ankle pulse wave velocity (baPWV) and exercise time were measured. All subjects were measured at two points--at 5th grade in elementary school (ages between 10 and 11 years) and 2nd grade in junior high school (8th grade, ages between 13 and 14 years). The relationship between the change values of adiposis over 3 years (from 5th grade to 8th grade) and blood pressure/baPWV at the age of 13-14 were analyzed with multiple regression analysis.

RESULTS

For boys, the change values in BMI and percentage body fat were correlated positively with systolic blood pressure. For girls, the change values in BMI and percentage body fat were correlated positively with systolic and diastolic blood pressures and baPWV.

CONCLUSIONS

In conclusion, raised blood pressure was already observed in obese early teens as a result of arteriosclerosis progression regardless exercise habit, and it was more apparent in girls.

Long-term treatment of hypogonadal men with testosterone produces substantial and sustained weight loss

OBJECTIVE

This study analyzed the effects of normalization of serum testosterone (T) levels on anthropometric parameters in hypogonadal men.

DESIGN AND METHODS

Open-label, single-center, cumulative, prospective registry study of 255 men (aged 33-69 years, mean 58.02 ± 6.30 years), with T levels below 12.13 nmol/L (mean: 9.93±1.38). 215 men for at least 2 years, 182 for 3 years, 148 for 4, and 116 for at least 5 years were studied. They received parenteral T undecanoate 1,000 mg/12 weeks after an initial interval of 6 weeks.

RESULTS

Body weight (BW) decreased from 106.22 ± 16.93 kg to 90.07 ± 9.51 kg. Waist circumference (WC) reduced from 107.24 ± 9.14 cm to 98.46 ± 7.39 cm. BMI (m/kg(2) ) declined from 33.9 ± 5.51 m/kg(2) to 29.13 ± 3.09 m/kg(2) . All parameters examined were statistically significant with P < 0.0001 versus baseline and versus the previous year over 5 years indicating a continuous weight loss over the full observation period. The mean per cent weight loss after 1 year was 4.16 ± 0.31%, after 2 years 7.54 ± 0.32%, after 3 years 9.23 ± 0.33%, after 4 years 11.42 ± 0.35% and after 5 years 13.57 ± 0.37%.

CONCLUSIONS

In an uncontrolled, observational cohort, normalizing serum T to normal physiological levels produced consistent loss of BW, WC, and BMI. These improvements were progressive over the full 5 years of the study.

Testosterone therapy in hypogonadal men results in sustained and clinically meaningful weight loss

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Hypogonadism is associated with increased fat mass and reduced muscle mass, which contributes to obesity and health risks, such as cardiovascular disease.Testosterone treatment of hypogonadal men improves muscle mass and reduces fat mass; however, many of these studies are of short duration.Thus, the long-term effects of testosterone on body anthropometry are not known.

WHAT THIS STUDY ADDS

Long-term testosterone treatment of hypogonadal men, up to 5 years duration, produced marked and significant decrease in body weight, waist circumference and body mass index. Hypogonadism contributes to reduced muscle mass and increased adiposity. Testosterone treatment ameliorates loss of muscle mass and reduces fat accumulation associated with hypogonadism. In this study, we evaluated the long-term effects of normalizing testosterone (T) levels in hypogonadal men on anthropometric parameters. Open-label, single-center, cumulative, prospective registry study of 261 men (32-84 years, mean 59.5 ± 8.4 years, with T levels ≤12 nmol L^-1 [mean: 7.7 ± 2.1]). Among the 261 men on T treatment, we followed up on 260 men for at least 2 years, 237 for 3 years, 195 for 4 years and 163 for at least 5 years. Subjects received parenteral T undecanoate 1000 mg every 12 weeks after an initial interval of 6 weeks. Body weight (BW), waist circumference (WC) and body mass index (BMI) were measured at baseline and yearly after treatment with T. BW decreased from 100.1 ± 14.0 kg to 92.5 ± 11.2 kg and WC was reduced from 107.7 ± 10.0 cm to 99.0 ± 9.1 cm. BMI declined from 31.7 ± 4.4 m kg^-2 to 29.4 ± 3.4 m kg^-2. All parameters examined were statistically significant vs. baseline and vs. the previous year over 5 years, indicating a continuous weight loss (WL) over the full observation period. The mean per cent WL was 3.2 ± 0.3% after 1 year, 5.6 ± 0.3%, after 2 years, 7.5 ± 0.3% after 3 years, 9.1 ± 0.3% after 4 years and 10.5 ± 0.4% after 5 years. The data obtained from this uncontrolled, observational, registry study suggest that raising serum T to normal physiological levels in hypogonadal men produces consistent loss in BW, WC and BMI. These marked improvements were progressive over the 5 years of the study.

Clinical review: Anogenital distance or digit length ratio as measures of fetal androgen exposure: relationship to male reproductive development and its disorders

CONTEXT

Male reproductive disorders evident at birth or in young adulthood are remarkably common. They are hypothesized to comprise a testicular dysgenesis syndrome (TDS), with a fetal origin involving mild androgen deficiency.

EVIDENCE ACQUISITION

Testing this hypothesis requires "seeing back in time." Two ways have been proposed: measurement of anogenital distance (AGD), or measurement of the 2:4 digit length ratio. This review assesses the evidence that they reflect fetal androgen exposure and might be used to provide insight into the origin of TDS disorders.

EVIDENCE SYNTHESIS

Supporting evidence for AGD derives from rat experimental studies that identified a fetal masculinization programming window, within which androgen action determines adult reproductive organ size, TDS disorders, and AGD. In humans, AGD is positively correlated to testis size, sperm count/fertility, penis length, and T levels, consistent with rat experimental data. The 2:4 digit ratio also shows associations with these parameters, but inconsistently between studies; evidence that the 2:4 digit ratio accurately reflects fetal androgen exposure is also equivocal.

CONCLUSIONS

AGD appears to provide a reliable guide to fetal androgen exposure, although available data are limited. The next steps are to: standardize AGD measurement; obtain age-specific population data; and use AGD to evaluate the importance of fetal androgens in determining reproductive disorders and variation in testis/penis size and sperm count in the normal population. These studies should identify what, if any, clinical applications of AGD measurement are feasible--for example, its ability to predict adult-onset reproductive function and disorders.

Endocrine changes (beyond diabetes) after bariatric surgery in adult life

Bariatric surgery is nowadays an effective therapeutic option for morbid obesity. Endocrinologists may thus have a growing opportunity to diagnose and treat obese patients eligible for surgery in pre- and post-operative phase. This requires a better understanding of endocrine changes caused by either obesity or weight loss surgery. Despite the large number of studies available in literature, only limited well-designed clinical trials have been performed so far to investigate changes of endocrine axes following bariatric procedures. There are still areas of unclear results such as female and male fertility, however, weight loss after bariatric surgery is considered to be associated with favorable effects on most endocrine axes. The aim of this clinical review is to overview the available literature on the effects of weight loss after bariatric surgery on the endocrine systems to suggest the most appropriate pre- and post-operative management of obese patients undergoing bariatric surgery in terms of "endocrine" health.

Protective cardiovascular and renal actions of vitamin D and estrogen

Both basic science and clinical studies support the concept that vitamin D deficiency is involved in the pathogenesis of cardiovascular and renal diseases through its association with diabetes, obesity, and hypertension. Understanding the underlying mechanisms may provide a rationale for advocating adequate intake of vitamin D and calcium in all populations, thereby preventing many chronic diseases. This review explores the effect of vitamin D deficiency in the development of cardiovascular and renal diseases, and the role of vitamin D supplementation on cardiovascular outcomes. In addition, it highlights the importance of vitamin D intake for the prevention of adverse long-term health consequences, and in ways to facilitate the management of cardiovascular disease. This is particularly true for African American and postmenopausal women, who are at added risk for cardiovascular disease. We suggest that the negative cardiovascular effects of low vitamin D in postmenopausal women could be improved by a combined treatment of vitamin D and sex steroids acting through endothelium-dependent and/or -independent mechanisms, resulting in the generation of nitric oxide and calcitonin gene-related peptide (CGRP).

Androgen therapy in men with testosterone deficiency: can testosterone reduce the risk of cardiovascular disease?

Obesity, hypertension, insulin resistance (IR), dyslipidaemia, impaired coagulation profile and chronic inflammation characterize cardiovascular risk factors in men. Adipose tissue is an active endocrine organ producing substances that suppress testosterone (T) production and visceral fat plays a key role in this process. Low T leads to further accumulation of fat mass, thus perpetuating a vicious circle. In this review, we discuss reduced levels of T and increased cardiovascular disease (CVD) risk factors by focusing on evidence derived from three different approaches. (i) epidemiological/ observational studies (without intervention); (ii) androgen deprivation therapy (ADT) studies (standard treatment in advanced prostate cancer); and (iii) T replacement therapy (TRT) in men with T deficiency (TD). In epidemiological studies, low T is associated with obesity, inflammation, atherosclerosis and the progression of atherosclerosis. Longitudinal epidemiological studies showed that low T is associated with an increased cardiovascular mortality. ADT brings about unfavourable changes in body composition, IR and dyslipidaemia. Increases in fibrinogen, plasminogen activator inhibitor 1 and C-reactive protein have also been observed. TRT in men with TD has consistently shown a decrease in fat mass and simultaneous increase in lean mass. T is a vasodilator and in long-term studies, it was shown to reduce blood pressure. There is increasing evidence that T treatment improves insulin sensitivity and lipid profiles. T may possess anti-inflammatory and anti-coagulatory properties and therefore TRT contributes to reduction of carotid intima media thickness. We suggest that T may have the potential to decrease CVD risk in men with androgen deficiency.

The relationship between sex hormones, sex hormone binding globulin and peripheral artery disease in older persons

OBJECTIVE

The prevalence of peripheral artery disease (PAD) increases with aging and is higher in persons with metabolic syndrome and diabetes. PAD is associated with adverse outcomes, including frailty and disability. The protective effect of testosterone and sex hormone binding globulin (SHBG) for diabetes in men suggests that the biological activity of sex hormones may affect PAD, especially in older populations.

METHODS

Nine hundred and twenty-one elderly subjects with data on SHBG, testosterone (T), estradiol (E2) were selected from InCHIANTI study. PAD was defined as an Ankle-Brachial Index (ABI) < 0.90. Logistic regression models adjusted for age (Model 1), age, BMI, insulin, interleukin-6, physical activity, smoking, chronic diseases including metabolic syndrome (Model 2), and a final model including also sex hormones (Model 3) were performed to test the relationship between SHBG, sex hormones and PAD.

RESULTS

The mean age (±SD) of the 419 men and 502 women was 75.0 ± 6.8 years. Sixty two participants (41 men, 21 women) had ABI < 0.90. Men with PAD had SHBG levels lower than men without PAD (p = 0.03). SHBG was negatively and independently associated with PAD in men (p = 0.028) but not in women. The relationship was however attenuated after adjusting for sex hormones (p = 0.07). The E2 was not significantly associated with PAD in both men and women. In women, but not in men, T was positively associated with PAD, even after adjusting for multiple confounders, including E2 (p = 0.01).

CONCLUSIONS

Low SHBG and high T levels are significantly and independently associated with the presence of PAD in older men and women, respectively.

Impaired aortic elastic properties in patients with adult-onset hypogonadism

BACKGROUND

Recent studies have shown a strong relationship between testosterone levels and vasomotor actions. The aim of this study is to compare the elastic properties of the aorta in male patients with hypogonadism and eugonadal healthy control subjects.

METHOD

A total of 22 male with hypogonadism (mean age: 35.2 ± 9.5 years, mean disease duration: 5.3 ± 1.8 years) and 25 age-, sex- and weight-matched eugonadal healthy subjects (mean age: 34.5 ± 8.2 years) were enrolled in the study. Aortic stiffness (β) index, aortic strain (AoS) and aortic distensibility (AoD) were calculated from the aortic diameters measured by transthoracic echocardiography and blood pressure obtained by sphygmomanometer.

RESULTS

The routinely performed echocardiographic parameters were similar between patient and control groups. There were significant differences between the control and patient groups in β index (1.75 ± 0.44 vs 2.68 ± 1.72, p < 0.001), AoS (18.52 ± 6.44 vs 12.35 ± 3.88%, p < 0.001) and AoD (7.56 ± 2.86 vs 3.96 ± 1.24, 10(-6) cm(2)/dyn, p < 0.001). There were statistically significant positive correlations between the serum total testosterone level and AoD (r = 0.539, p < 0.001) and AoS (r = 0.372, p = 0.036); moreover, there was a negative correlation between the serum total testosterone level and β index (r = - 0.462, p = 0.001). In multivariate analysis, serum total testosterone level was significantly related with AoD, AoS and β index (respectively, RR = 2.88, p = 0.004; RR = 3.45, p = 0.001; RR = 2.64, p = 0.01).

CONCLUSION

The study results showed that aortic elasticity was impaired in patients with hypogonadism. We also have demonstrated a statistically significant correlation between aortic elastic properties and the serum total testosterone level.

Dihydrotestosterone inhibits lectin-like oxidized-LDL receptor-1 expression in aortic endothelial cells via a NF-κB/AP-1-mediated mechanism

The mechanisms involved in the antiatherosclerotic effects of androgens are unclear. Although lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in endothelial cells plays critical roles in atherosclerosis, the effects of androgens on endothelial LOX-1 expression has not been examined. Therefore, to investigate the effects of dihydrotestosterone (DHT) on LOX-1 expression in rabbit aortic endothelial cells and cultured human aortic endothelial cells (HAEC), pellets containing DHT or placebo were s.c. implanted into 26 male New Zealand white rabbits at the time of castration or sham operation. The rabbits were then fed a high-cholesterol diet (HCD) for 2 wk. Microscopic examination of the aortic arch revealed that DHT significantly reduced HCD-induced LOX-1 expression in endothelial cells compared with placebo. In cultured HAEC, DHT at concentrations above 10(-9) to 10(-7) mol/liter inhibited TNFα-induced LOX-1 mRNA and protein expression. Deletion and mutation analysis of human LOX-1 promoter-luciferase constructs transfected into HAEC with an androgen receptor (AR) expression plasmid revealed that the 12-O-tetradecanoylphorbol-13-acetate (TPA) response element (TRE; nucleotides -60/-53) contributed to the inhibitory effects of DHT on TNFα-induced LOX-1 expression. Chromatin immunoprecipitation (ChIP) and re-ChIP assays revealed that TNFα- and TPA-dependent enrichment of p65 and phosphorylated c-Jun in the TRE chromatin region was inhibited by DHT-AR. Consistent with these results, DHT also suppressed TPA-induced expression of LOX-1. In conclusion, DHT exerts antiatherosclerotic effects by suppressing endothelial LOX-1 expression. This effect is partly mediated by the suppression of nuclear factor-κB- and activator protein 1-dependent activation of the LOX-1 promoter.

Correlation between sex hormone levels and obesity in the elderly male

OBJECTIVE

To investigate the levels of sex hormones and androgen receptor (AR) in elderly male patients and to explore a possible correlation with obesity.

METHODS

The cross-sectional study included 314 Elderly males (age ≥ 65 year). Of these subjects, 104 were healthy (age range 65-92 year; mean 71.38 ± 5.154 year), 74 were obese (65-87 year; 71.32 ± 4.74 year), and 111 were overweight (65-85 year; 71.43 ± 5.03 year). The following parameters were measured: total testosterone (TT), free testosterone, dehydroepiandrosterone sulfate, sex hormone-binding globulin (SHBG), estradiol (E2), luteinizing hormone, follicle-stimulating hormone and AR.

RESULTS

(i) The levels of TT and SHBG in the obesity group were significantly lower than those in non-obese subjects. (ii) Body mass index (BMI) negatively correlated with TT and SHBG. (iii) Multiple regression analysis revealed that TT (β: -0.230; p = 0.045) and SHBG (β: -0.163; p = 0.02) were statistically correlated with BMI.

CONCLUSION

Testosterone levels in the obese population were significantly lower than in the non-obese population and there is a significant association between testosterone levels and the extent of obesity.

Influence of age and sex on the pressor response following a spontaneous burst of muscle sympathetic nerve activity

The sympathetic nervous system is critical for the beat-to-beat regulation of arterial blood pressure (BP). Although studies have examined age- and sex-related effects on BP control, findings are inconsistent and limited data are available in postmenopausal women. In addition, the majority of studies have focused on time-averaged responses without consideration for potential beat-to-beat alterations. Thus we examined whether the ability of muscle sympathetic nerve activity (MSNA) to modulate BP on a beat-to-beat basis is affected by age or sex. BP and MSNA were measured during supine rest in 40 young (20 men) and 40 older (20 men) healthy subjects. Beat-to-beat fluctuations in mean arterial pressure (MAP) were characterized for 15 cardiac cycles after each MSNA burst using signal averaging. The rise in MAP following an MSNA burst was similar between young men and women (+2.64 ± 0.3 vs. +2.57 ± 0.3 mmHg, respectively). However, the magnitude of the increase in MAP after an MSNA burst was reduced in older compared with young subjects (P < 0.05). Moreover, the attenuation of the pressor response was greater in older women (+1.20 ± 0.1 mmHg) compared with older men (+1.72 ± 0.2 mmHg; P < 0.05). Interestingly, in all groups, MAP consistently decreased after cardiac cycles without MSNA bursts (nonbursts) with the magnitude of fall greatest in older men. In summary, healthy aging is associated with an attenuated beat-to-beat increase in BP after a spontaneous MSNA burst, and this attenuation is more pronounced in postmenopausal women. Furthermore, our nonburst findings highlight the importance of sympathetic vasoconstrictor activity to maintain beat-to-beat BP, particularly in older men.

Testosterone as potential effective therapy in treatment of obesity in men with testosterone deficiency: a review

OBJECTIVE

Obesity negatively affects human health. Limiting food intake, while producing some weight loss, results in reduction of lean body mass. Combined with moderate exercise it produces significant weight loss, maintains lean body mass and improves insulin sensitivity, but appears difficult to adhere to. Bariatric surgery is clinically effective for severely obese individuals compared with non-surgical interventions, but has limitations. Clinical and pre-clinical studies have implicated a role for testosterone (T) in the patho-physiology of obesity.

EVIDENCE ACQUISITION AND SYNTHESIS

A literature search in PubMed on the role of T in counteracting obesity and its complications.

RESULTS

Obesity per se impairs testicular T biosynthesis. Furthermore, lower-than-normal T levels increase accumulation of fat depots, particularly abdominal (visceral) fat. This fat distribution is associated with development of metabolic syndrome (MetS) and its sequels, namely type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). T treatment reverses fat accumulation with significant improvement in lean body mass, insulin sensitivity and biochemical profiles of cardiovascular risk. The contribution of T to combating obesity in hypogonadal men remains largely unknown to medical professionals managing patients with obesity and metabolic syndrome. Many physicians associate T treatment in men with risks for prostate malignancy and CVD. These beliefs are not supported by recent insights.

CONCLUSION

While overall treatment of obesity is unsuccessful, T treatment of hypogonadal men may be effective, also because it improves mood, energy, reduces fatigue and may motivate men to adhere to diet and exercise regimens designed to combat obesity.

Testosterone supplementation in male obese Zucker rats reduces body weight and improves insulin sensitivity but increases blood pressure

Androgen levels are lower in obese men as compared with normal weight individuals. However, there are no safety data regarding the chronic use of androgen supplements in middle-aged men. The present study was undertaken to determine the cardiovascular and metabolic effects of chronic (10 weeks) testosterone treatment in male obese Zucker rats, starting at 22 weeks of age, when testosterone levels were significantly decreased. Testosterone supplements increased plasma levels, 10-fold in both obese Zucker rats and lean Zucker rats. In obese Zucker rats, testosterone supplements reduced body weight, plasma insulin, and cholesterol levels and improved the oral glucose tolerance test. None of these parameters were affected in lean Zucker rats. Mean arterial pressure was significantly increased in obese Zucker rats but not lean Zucker rats. Testosterone supplements increased proteinuria and accelerated renal injury in lean Zucker rats only. Thus, treatment of obese men with chronic testosterone supplements should be done with careful monitoring of blood pressure.

Sexual dimorphism in ischemic stroke: lessons from the laboratory

Ischemic stroke is emerging as a major health problem for elderly women. Women have lower stroke incidence than men until an advanced age, when the epidemiology of ischemic stroke shifts and incidence rises dramatically in women. Experimental models of rodent stroke have replicated this clinical epidemiology, with exacerbated injury in older compared with young female rodents. Many of the detrimental effects of aging on ischemic stroke outcome in females can be replicated by ovariectomy, suggesting that hormones such as estrogen play a neuroprotective role. However, emerging data suggest that the molecular mechanisms leading to ischemic cell death differ in the two sexes, and these effects may be independent of circulating hormone levels. This article highlights recent clinical and experimental literature on sex differences in stroke outcomes and mechanisms.