Estradiol and inflammatory markers in older men

Endogenous Sex Hormone Levels and Myocardial Fibrosis in Men and Postmenopausal Women

BACKGROUND

Sex hormone (SH) imbalances have been linked to a higher risk of heart failure in both sexes. However, mechanisms that underlie this relationship remain unclear. We examined the association of baseline SH with interstitial and replacement myocardial fibrosis in the MESA (Multi-Ethnic Study of Atherosclerosis) using cardiac magnetic resonance (CMR) T1 mapping and late gadolinium enhancement (LGE).

OBJECTIVES

The purpose of this study was to assess the link between baseline sex hormone levels and myocardial fibrosis in the MESA cohort using CMR.

METHODS

A total of 2,324 participants (men and postmenopausal women [PMW]) were included in the MESA with SH measured at baseline and had underwent CMR 10 years later. All analyses were stratified by sex and age. Regression models were constructed to assess the associations of baseline SH with extracellular volume (ECV)% and native T1 time and with LGE. Higher native T1 time and ECV% are interpreted as evidence of increasing interstitial myocardial fibrosis (IMF). Given the limited number of myocardial scars present in PMW, analysis of LGE was limited to men.

RESULTS

Among older men (age ≥65 years), a 1-SD increment higher free testosterone was significantly associated with 2.45% lower ECV% and 21.5% lower native T1 time, while a 1-SD increment higher bioavailable testosterone was associated with 12.5% lower native T1 time. A 1-SD increment greater sex hormone-binding globulin level was associated with 1% higher ECV%. Among PMW of 55 to 64 years, a 1-SD increment higher total testosterone was associated with 9.5% lower native T1 time. Higher levels of estradiol in older men were independently associated with higher odds of having a myocardial scar (OR: 4.10; 95% CI: 1.35-12.40; P = 0.01).

CONCLUSIONS

Among older men, SH imbalances at initial evaluation were independently associated with CMR defined IMF and replacement fibrosis, respectively; while increasing total testosterone in middle-aged PMW was associated with lesser marker of IMF. (JACC Adv 2023;2:100320) Published by Elsevier on behalf of the American College of Cardiology Foundation.

Temporal changes in the microglial proteome of male and female mice after a diffuse brain injury using label-free quantitative proteomics

Traumatic brain injury (TBI) triggers neuroinflammatory cascades mediated by microglia, which promotes tissue repair in the short-term. These cascades may exacerbate TBI-induced tissue damage and symptoms in the months to years post-injury. However, the progression of the microglial function across time post-injury and whether this differs between biological sexes is not well understood. In this study, we examined the microglial proteome at 3-, 7-, or 28-days after a midline fluid percussion injury (mFPI) in male and female mice using label-free quantitative proteomics. Data are available via ProteomeXchange with identifier PXD033628. We identified a reduction in microglial proteins involved with clearance of neuronal debris via phagocytosis at 3- and 7-days post-injury. At 28 days post-injury, pro-inflammatory proteins were decreased and anti-inflammatory proteins were increased in microglia. These results indicate a reduction in microglial clearance of neuronal debris in the days post-injury with a shift to anti-inflammatory function by 28 days following TBI. The changes in the microglial proteome that occurred across time post-injury did not differ between biological sexes. However, we did identify an increase in microglial proteins related to pro-inflammation and phagocytosis as well as insulin and estrogen signaling in males compared with female mice that occurred with or without a brain injury. Although the microglial response was similar between males and females up to 28 days following TBI, biological sex differences in the microglial proteome, regardless of TBI, has implications for the efficacy of treatment strategies targeting the microglial response post-injury.

Total Testosterone to Estradiol Ratio as a Predictor Marker of Metabolic Syndrome in Males

Nowadays, metabolic syndrome (MetS) represents a global health challenge in developed and developing countries. The sex hormones disorders in males are related to many clinical co-morbidities. This study aimed to evaluate the total testosterone (TT) to estradiol (E2) ratio as a predictor marker of MetS. This case-control study included 88 MetS patients and 88 healthy individuals (control), in the age range of 18-69 years who were selected among patients who were referring to an outpatient clinic, using a convenience sampling method. The study participants were selected based on their medical history and physical examination, which included waist circumference, blood pressure, serum E2, TT, fasting blood glucose (FBG), triglyceride (TG), and high-density lipoprotein-cholesterol (HDL-C). Diagnosis of MetS was confirmed according to the National Cholesterol Education Program Adult Treatment Panel III guidelines. The findings revealed that the mean TT level was significantly lower among patients with MetS (P<0.001), while the mean E2 level was significantly higher among patients with MetS (P<0.001). The mean TT to E2 ratio was significantly lower among patients with MetS (OR=9.6, P<0.001). There was a significant correlation between MetS components and TT to E2 ratio and waist circumference (WC) (r = - 0.49, P<0.0001). The means of weight, WC, blood pressure, and FBG levels were significantly higher in patients with MetS (P<0.001, P<0.001, P<0.001, P=0.04, respectively), and the lipid profile of patients with MetS was abnormal (TG, P<0.001, HDL-C, P<0.001). Eventually, it can be concluded that the TT to E2 ratio can be regarded as a significant predictor of MetS in males.

Relationship between penile erection and the ratio of estradiol to testosterone: A retrospective study

Previous studies have found that the ratio of estradiol to testosterone (E2/T ratio) has a negative effect on sexual function, but the relationship between the E2/T ratio and erection of the penis is not clarified. We conducted a retrospective study of 183 patients with erectile dysfunction and 52 healthy men to investigate the relationship between penis base erection and tip erection. All participants underwent nocturnal penile tumescence tests and medical history checks and had relevant biochemical and endocrine indicators measured. The ratio of estradiol to testosterone was calculated. The relationship between E2/T ratio and erectile time of penile tip and penile base was determined by univariate analysis, multivariate analysis and stratification analysis. After adjusting for mixed factors, the results showed that the E2/T ratio had a more significant negative effect on the base of the penis compared with the tip of the penis (Hazard ratio: -4.34 95% CI: -6.52, -2.16 p = .0001). Moreover, when the effective erection time was ≥10 min, the negative effect of E2/T on penile root erection was more obvious (HR ratio: -4.46 95% CI: -6.50, -2.43 p < .0001). In summary, our study demonstrated a negative relationship between E2/T ratio and penile erection, particularly at the root of the penis.

Testosterone to oestradiol ratio reflects systemic and plaque inflammation and predicts future cardiovascular events in men with severe atherosclerosis

Aims

The effects of testosterone on cardiovascular disease (CVD) as reported in literature have been ambiguous. Recently, the interplay between testosterone and oestradiol as assessed by testosterone/oestradiol (T/E2) ratio was suggested to be better informative on the normal physiological balance. Considering the role in CVD, we hypothesized that a low T/E2 ratio in men with CVD is associated with increased inflammation, a more unstable plaque and a worse cardiovascular outcome.

Methods and results

Testosterone and oestradiol concentrations were determined in blood samples of 611 male carotid endarterectomy patients included in the Athero-Express Biobank Study. T/E2 ratio was associated with baseline characteristics, atherosclerotic plaque specimens, inflammatory biomarkers, and 3 year follow-up information. Patients with low T/E2 ratio had more unfavourable inflammatory profiles compared with patients with high T/E2 as observed by higher levels of C-reactive protein [2.81 μg/mL vs. 1.22 μg/mL (P < 0.001)] and higher leucocyte counts [8.98*109/L vs. 7.75*109/L (P = 0.001)] in blood. In atherosclerotic plaques, a negative association between T/E2 ratio and number of neutrophils [B = -0.366 (P = 0.012)], plaque calcifications [OR: 0.816 (P = 0.044)], interleukin-6 (IL-6) [B = -0.15 (P = 0.009)], and IL-6 receptor [B = -0.13 (P = 0.024)] was found. Furthermore, in multivariate Cox regression analysis, low T/E2 ratio was independently associated with an increased risk for major cardiovascular events (MACE) during 3 year follow-up [hazard ratio 1.67 (95% confidence interval 1.02-2.76), P = 0.043]. In men with elevated body mass index (BMI), these effects were strongest.

Conclusion

In male patients with manifest atherosclerotic disease, low T/E2 ratio was associated with increased systemic inflammation, increased inflammatory plaque proteins, and an increased risk of future MACE as compared to men with normal T/E2 ratio. These effects are strongest in men with elevated BMI and are expected to be affected by aromatase activity in white fat tissues. Normalization of T/E2 ratio may be considered as target for the secondary prevention of CVD in men.

Inherent X-Linked Genetic Variability and Cellular Mosaicism Unique to Females Contribute to Sex-Related Differences in the Innate Immune Response

Females have a longer lifespan and better general health than males. Considerable number of studies also demonstrated that, after trauma and sepsis, females present better outcomes as compared to males indicating sex-related differences in the innate immune response. The current notion is that differences in the immuno-modulatory effects of sex hormones are the underlying causative mechanism. However, the field remains controversial and the exclusive role of sex hormones has been challenged. Here, we propose that polymorphic X-linked immune competent genes, which are abundant in the population are important players in sex-based immuno-modulation and play a key role in causing sex-related outcome differences following trauma or sepsis. We describe the differences in X chromosome (ChrX) regulation between males and females and its consequences in the context of common X-linked polymorphisms at the individual as well as population level. We also discuss the potential pathophysiological and immune-modulatory aspects of ChrX cellular mosaicism, which is unique to females and how this may contribute to sex-biased immune-modulation. The potential confounding effects of ChrX skewing of cell progenitors at the bone marrow is also presented together with aspects of acute trauma-induced de novo ChrX skewing at the periphery. In support of the hypothesis, novel observations indicating ChrX skewing in a female trauma cohort as well as case studies depicting the temporal relationship between trauma-induced cellular skewing and the clinical course are also described. Finally, we list and discuss a selected set of polymorphic X-linked genes, which are frequent in the population and have key regulatory or metabolic functions in the innate immune response and, therefore, are primary candidates for mediating sex-biased immune responses. We conclude that sex-related differences in a variety of disease processes including the innate inflammatory response to injury and infection may be related to the abundance of X-linked polymorphic immune-competent genes, differences in ChrX regulation, and inheritance patterns between the sexes and the presence of X-linked cellular mosaicism, which is unique to females.

Association between endogenous sex steroid hormones and inflammatory biomarkers in US men

Sex steroid hormones and inflammatory biomarkers are both associated with the development and progression of chronic diseases, but their interrelationship is relatively uncharacterized. We examined the association of sex hormones and sex hormone-binding globulin (SHBG) with biomarkers of inflammation, C-reactive protein (CRP) and white blood cell (WBC) count. The study included data from 809 adult men in the National Health and Nutrition Examination Survey 1999-2004. Geometric means and 95% confidence intervals were estimated separately for CRP and WBC concentrations by sex steroid hormones and SHBG using weighted linear regression models. Higher concentrations of total (slope per one quintile in concentration, -0.18; p-trend, 0.001) and calculated free (slope, -0.13; p-trend, 0.03) testosterone were statistically significantly associated with lower concentrations of CRP, but not with WBC count. Men in the bottom quintile of total testosterone (≤3.3 ng/mL), who might be considered to have clinically low testosterone, were more likely to have elevated CRP (≥3 mg/L) compared with men in the top four quintiles (OR, 1.61; 95% CI, 1.00-2.61). Total and calculated free estradiol (E2) were positively associated with both CRP (Total E2: slope, 0.14; p-trend, <0.001; Free E2: slope, 0.15; p-trend, <0.001) and WBC (Total E2: slope, 0.02; p-trend, 0.08; Free E2: slope, 0.02; p-trend, 0.02) concentrations. SHBG concentrations were inversely associated with WBC count (slope, -0.03; p-trend, 0.04), but not with CRP. These cross-sectional findings are consistent with the hypothesis that higher androgen and lower oestrogen concentrations may have an anti-inflammatory effect in men.

Comparisons of immunoassay and mass spectrometry measurements of serum estradiol levels and their influence on clinical association studies in men

CONTEXT

Immunoassay-based techniques, routinely used to measure serum estradiol (E2), are known to have reduced specificity, especially at lower concentrations, when compared with the gold standard technique of mass spectrometry (MS). Different measurement techniques may be responsible for the conflicting results of associations between serum E2 and clinical phenotypes in men.

OBJECTIVE

Our objective was to compare immunoassay and MS measurements of E2 levels in men and evaluate associations with clinical phenotypes.

DESIGN AND SETTING

Middle-aged and older male subjects participating in the population-based Osteoporotic Fractures in Men (MrOS) Sweden study (n = 2599), MrOS US (n = 688), and the European Male Aging Study (n = 2908) were included.

MAIN OUTCOME MEASURES

Immunoassay and MS measurements of serum E2 were compared and related to bone mineral density (BMD; measured by dual energy x-ray absorptiometry) and ankle-brachial index.

RESULTS

Within each cohort, serum E2 levels obtained by immunoassay and MS correlated moderately (Spearman rank correlation coefficient rS 0.53-0.76). Serum C-reactive protein (CRP) levels associated significantly (albeit to a low extent, rS = 0.29) with immunoassay E2 but not with MS E2 levels. Similar associations of immunoassay E2 and MS E2 were seen with lumbar spine and total hip BMD, independent of serum CRP. However, immunoassay E2, but not MS E2, associated inversely with ankle-brachial index, and this correlation was lost after adjustment for CRP.

CONCLUSIONS

Our findings suggest interference in the immunoassay E2 analyses, possibly by CRP or a CRP-associated factor. Although associations with BMD remain unaffected, this might imply for a reevaluation of previous association studies between immunoassay E2 levels and inflammation-related outcomes.

SHBG and endothelial function in older subjects

BACKGROUND

Endothelial dysfunction is predictor of cardiovascular diseases that have different prevalence in men and women before menopause. Sex hormones and sex hormone binding globulin (SHBG), novel risk factors for diabetes and cardiovascular diseases even in older individuals, might explain this difference. However, the relationship between these hormones and endothelial function has never been addressed in the elderly.

METHODS AND RESULTS

430 men and,424 women 70 years older of Prospective Study of the Vasculature in Uppsala Seniors study, with complete data on SHBG, testosterone(T), estradiol(E2), endothelium-independent vasodilation (EIDV), endothelium-dependent vasodilation(EDV), flow-mediated vasodilation (FMD) and the pulse wave analysis (reflection index, RI) were evaluated. Multivariate regression analysis adjusted for confounders was used to assess the relationship between T, E2, SHBG and endothelial function. In men we found a positive relationship between SHBG and EDV (β ± SE 3.60 ± 0.83, p<0.0001), EIDV (2.42 ± 0.58, p<0.0001) but not with FMD. The relationship between SHBG and EDV and EIDV was maintained after adjustment for sex (1.64 ± 0.47, p<0.001 and 1.79 ± 0.35, p<0.0006, respectively). After adjustment for confounders, the relationship between SHBG and EDV and EIDV was still statistically significant (2.63 ± 0.90 and 1.86 ± 0.63, p = 0.004 for both). In women SHBG and EIDV were positively associated (1.58 ± 0.46; p = 0.0007), and this relationship was independent of sex (1.79 ± 0.35; p<0.001). No significant interaction SHBG * SEX was found for EIDV (p = 0.72). In a combined analysis in two sexes, SHBG and EIDV were positively associated (1.13 ± 0.45; p = 0.01). SHBG was not associated with EDV, FMD and RI. No significant relationship was found between T or E2 and EDV, EIDV, FMD or RI in both sexes.

CONCLUSIONS

In older men SHBG, but not T and E2, is positively and independently associated with EDV in resistance arteries. In both sexes, SHBG was positively and independently associated with EIDV.

Endogenous sex hormones and C-reactive protein in healthy Chinese men

OBJECTIVE

To examine the association of endogenous sex hormones and sex hormone-binding globulin (SHBG) with C-reactive protein (CRP) in Chinese men.

DESIGN AND PARTICIPANTS

The study population comprised 1989 men at baseline recruitment of a population-based cohort in China. Participant information on risk factors was collected by a face-to-face interview and clinical examination. All subjects in the study were without taking any kind of medication for anti-inflammation purpose or treatment of hypogonadism and with CRP value less than 10 mg/l. Data were analysed using linear regression analyses.

RESULTS

Higher levels of total testosterone (TT, β = -0.114, 95%CI, -0.162 to -0.065), free testosterone (β = -0.059, 95%CI, -0.106 to -0.012) and SHBG (β = -0.116, 95%CI, -0.169 to -0.063) were statistically significantly related to lower levels of CRP, after adjustment for age, waist circumference (WC), triglycerides, high-density lipoprotein cholesterol, fasting glucose, insulin, smoking status, hypertension, diabetes and family history of hypertension or diabetes. In the subgroup of men with body mass index ≥ 27.5 kg/m(2) or with metabolic syndrome, findings for TT and SHBG were more pronounced, whereas the associations of TT with CRP were attenuated and nonstatistically significant among subjects with WC ≥ 90 cm or with insulin resistance. No associations were observed between estradiol, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and CRP.

CONCLUSIONS

We have confirmed the association of androgens with reduced inflammation as measured by CRP in Chinese men. This is independent of conventional cardiovascular risk factors and is explained in part by markers of central obesity and insulin resistance, rather than metabolic syndrome.

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.

Age trends in estradiol and estrone levels measured using liquid chromatography tandem mass spectrometry in community-dwelling men of the Framingham Heart Study

BACKGROUND

Age trends in estradiol and estrone levels in men and how lifestyle factors, comorbid conditions, testosterone, and sex hormone-binding globulin affect these age trends remain poorly understood, and were examined in men of the Framingham Heart Study.

METHODS

Estrone and estradiol concentrations were measured in morning fasting samples using liquid chromatography tandem mass spectrometry in men of Framingham Offspring Generation. Free estradiol was calculated using a law of mass action equation.

RESULTS

There were 1,461 eligible men (mean age [±SD] 61.1±9.5 years and body mass index [BMI] 28.8±4.5kg/m(2)). Total estradiol and estrone were positively associated with age, but free estradiol was negatively associated with age. Age-related increase in total estrone was greater than that in total estradiol. Estrone was positively associated with smoking, BMI, and testosterone, and total and free estradiol with diabetes, BMI, testosterone, and comorbid conditions; additionally, free estradiol was associated negatively with smoking. Collectively, age, BMI, testosterone, and other health and behavioral factors explained only 18% of variance in estradiol, and 9% of variance in estrone levels. Men in the highest quintile of estrone levels had significantly higher age and BMI, and a higher prevalence of smoking, diabetes, and cardiovascular disease than others, whereas those in the highest quintile of estradiol had higher BMI than others.

CONCLUSIONS

Total estrone and estradiol levels in men, measured using liquid chromatography tandem mass spectrometry, revealed significant age-related increases that were only partially accounted for by cross-sectional differences in BMI, diabetes status, and other comorbidities and health behaviors. Longitudinal studies are needed to confirm these findings.

Sex hormone levels and sexual dysfunction in men after coronary artery bypass graft

BACKGROUND

Sexual dysfunction is one of the most common problems in men after coronary artery bypass graft (CABG). Etiology of sexual dysfunction in these patients may be psychological or organic due to hormonal changes.

OBJECTIVE

The purpose was to evaluate the incidence and type of sexual dysfunction and changes in serum concentration of sex hormones in male patients undergoing on-pump CABG.

MATERIALS AND METHODS

In this before and after study we enrolled 40 men aged less than 70 years who were candidate for on-pump CABG. Interviews were done by a physician before and 12 weeks after the operation in regard to the impact of surgery on their sexual activities. The serum levels of 6 sex hormones were also determined. The statistical tests used for data analysis included analysis of variance, McNemar's test and chi-square analysis.

RESULTS

The mean±SD age of the patients was 51.27±7.86 years. Incidence of sexual dysfunction was 22.5% (9 cases) before and 47.7% (19 cases) after operation. Types of sexual dysfunction were premature ejaculation (5% before, 2.5% after), impotence (7.5% before, 12.5% after) and loss of libido (10% before, 32% after). The level of sex hormones were generally decreased after operation but it was statistically significant only for estrogen (p-value=0.02).

CONCLUSION

Sexual dysfunction and reduction in serum level of sex hormones are common in patients before on-pump CABG and mostly get worse after surgery. Complementary studies are suggested for prevention and treatment of sexual dysfunction.

Risk factors associated with cardiovascular events during testosterone administration in older men with mobility limitation

BACKGROUND

Testosterone in Older Men with Mobility Limitations Trial found an increased incidence of cardiovascular events in men randomized to testosterone, resulting in enrollment cessation by trial's Data and Safety Monitoring Board. We evaluated changes in gonadal hormones and markers of inflammation and coagulation to elucidate risk factors associated with cardiovascular events.

METHODS

Men aged 65 years or more, with mobility limitation, total testosterone 100-350 ng/dL, or free testosterone less than 50 pg/mL, were randomized to placebo or 10 g testosterone gel daily for 6 months. Changes in total and free testosterone, estradiol and estrone, C-reactive protein, interleukin 6, fibrinogen, plasminogen activator inhibitor-1, and pro-brain naturetic peptide were compared between groups and within the testosterone group between subjects who experienced cardiovascular events and those who did not.

RESULTS

Of 209 men randomized (mean age 74 years), gonadal hormones and biomarkers were available in 179 men. Baseline body mass index, gonadal hormones, lipids, Framingham risk scores, and other biomarkers were similar in the two treatment groups. Within the testosterone group, the 6-month increase in free testosterone was significantly greater in men who experienced cardiovascular events than in those who did not [mean (95% confidence interval), 10.6 (4.6-16.7) vs 5.2 (3.0-7.5) ng/dL, p = .05]. In multivariable logistic regression analysis, the change in the serum levels of free testosterone was associated with cardiovascular events.

CONCLUSION

Mobility-limited older men who experienced cardiovascular events had greater increases in serum free testosterone levels than those who did not.

Relationship between testosterone deficiency and cardiovascular risk and mortality in adult men

Classic male hypogonadism is associated with known adverse effects including decreased libido, erectile dysfunction, osteoporosis, and changes in body composition. Recently, we have come to appreciate that reduction in serum testosterone (T) levels resulting from aging or chronic disease or androgen deprivation therapy (ADT) have consequences similar to those seen in classic male hypogonadism which include increased fat mass, decreased lean body mass, decreased muscle strength, and sexual dysfunction. These data suggest that low T levels may represent a newly recognized cardiometabolic risk factor. Therefore, we carried out a careful review of the literature, focusing on major turning points of research and studies which gave more important and controversial contribution to the cardiovascular role of T. Observational studies and clinical trials investigating the relationship between T levels and cardiovascular disease and mortality were identified byMedline search. The results were synthesized, tabulated, and interpreted. The aim of this review is to discuss the association between low T levels and adverse metabolic profile such as insulin resistance, metabolic syndrome, and diabetes. We will also investigate the potential mechanisms by which male hypogonadism, especially age related or induced by ADT, may increase cardio-metabolic risk. Finally we will detail the emerging relationship between low T and mortality in men addressing also the reverse hypothesis that low T has a protective role by turning off T-dependent functions.

The effects of injected testosterone dose and age on the conversion of testosterone to estradiol and dihydrotestosterone in young and older men

BACKGROUND

During testosterone (T) therapy, T is partly converted to 17beta-estradiol (E2) and 5alpha-dihydrotestosterone (DHT). Effects of age, testosterone dose, and body composition on total and free E2 and DHT levels are unknown.

OBJECTIVE

We evaluated age and dose-related differences in E2 and DHT levels in response to graded doses of testosterone enanthate in young and older men.

METHODS

Fifty-one young (aged 19-35 yr) and 52 older (aged 59-75 yr) men completed treatment with monthly injections of a GnRH agonist plus randomly assigned weekly doses of testosterone enanthate (25, 50, 125, 300, or 600 mg) for 5 months.

RESULTS

During testosterone administration, total and free E2 levels increased dose-dependently (dose effect, P<0.001) in both young and older men. Total and free E2 levels and E2:T ratios during T administration were higher in older than young men, but age-related differences in free E2 and free E2:T ratios were not significant after adjusting for testosterone levels, percentage fat mass, and SHBG. DHT levels and DHT:T ratios were dose-related but did not differ between young and older men. Mechanistic modeling of free hormone data revealed that the conversions of T to E2 and DHT were both consistent with saturable Michaelis-Menten kinetics. The in vivo Km values were estimated to be 1.83 nm for aromatase and 3.35 nm for 5alpha-reductase, independent of age. The Vmax parameter for E2 was 40% higher in older men than younger men, but Vmax for DHT was not significantly different between age groups.

CONCLUSIONS

During im testosterone administration, E2 and DHT levels exhibit saturable increases with dose. The rate of whole body aromatization is higher in older men, partly related to their higher percentage fat mass, SHBG, and testosterone levels.

Association of sex hormones and C-reactive protein levels in men

OBJECTIVES

The age-associated decline in sex hormone levels in men is paralleled by an increase in cardiovascular disease and associated risk factors including low grade chronic inflammation. The objective of this analysis was to investigate the association between sex hormone levels and C-reactive protein (CRP) in a population-based sample of men.

DESIGN

Population-based, cross-sectional observational survey.

PARTICIPANTS

A multistage stratified design was used to recruit a random sample of 2301 racially and ethnically diverse men age 30-79 years. Blood samples were obtained on 1899 men. Analyses were conducted on 1559 men with complete data on CRP and sex hormone levels.

MEASUREMENTS

High-sensitivity CRP levels. The association between CRP and sex hormone levels was assessed using multiple linear regression models.

RESULTS

An inverse association was observed, in both bivariate and multivariate analyses, between CRP and total testosterone, free testosterone and SHBG levels. These associations remained statistically significant after adjusting for age, body mass index, comorbid conditions and lifestyle factors. A positive trend between oestradiol (total and free) and CRP levels was not statistically significant.

CONCLUSIONS

A robust, inverse dose-response correlation between testosterone and SHBG levels with CRP levels provides further evidence of a potential role of androgens in inflammatory processes.

Endogenous steroids measured by high-specificity liquid chromatography-tandem mass spectrometry and prevalent cardiovascular disease in 70-year-old men and women

CONTEXT

There is a need for increased knowledge about endogenous sex hormone levels and clinical outcomes of risk/benefit. Immunoassays have poor specificity to reliably measure low steroid concentrations in elderly.

OBJECTIVE

The objective of the study was to evaluate plasma steroid concentrations with regard to prevalent cardiovascular disease (CVD) in elderly, using mass spectrometry.

SETTING

The study was conducted at a university hospital research unit.

DESIGN AND METHODS

Plasma samples were analyzed from 202 70-yr-olds as part of a large population-based study, Prospective Investigation of the Vasculature in Uppsala Seniors. Twenty-eight of these had prevalent CVD. Eleven steroids were quantified, using liquid chromatography-tandem mass spectrometry. Women with current/previous menopausal hormone therapy (n = 35) were excluded.

RESULTS

Men without prevalent CVD had higher plasma 17beta-estradiol (E2), compared with women. Men with prevalent CVD, compared with those without, had lower 17-hydroxypregnenolone (17OHPregn), 17-hydroxyprogesterone, and higher estrone/androstenedione and E2/testosterone (T) (aromatase activity). Women with prevalent CVD had lower pregnenolone, 17OHPregn, and dehydroepiandrosterone (DHEA) but higher DHEA/17OHPregn, androstenedione/DHEA, E2/T, E2/estrone, and E2/SHBG. The aromatase index, E2/T, was higher for prevalent CVD in both sexes. Adjustment for statin use, smoking, and body mass index yielded additional significant differences in men, whereas some were lost in women. Logistic regression indicated strong associations between prevalent CVD and low 17OHPregn, adjusted odds ratio of 0.18, 95% confidence interval (0.06-0.61); P = 0.006, in women and low 17-hydroxyprogesterone, 0.45 (0.25-0.80); P = 0.007 in men, most likely caused by increased throughput (consumption) toward estrogen synthesis.

CONCLUSIONS

Prevalent CVD was associated with indications of lower androgen precursors, increased aromatase activity, and higher estrogen levels in both sexes. Results might represent an endogenous response to a condition of developing atherosclerosis, rather than a causative relationship. Furthermore studies are needed.