Serum Free Estradiol Research Articles

Salivary estradiol as a surrogate marker for serum estradiol in assisted reproduction treatment

IntroductionControlled ovarian hyper-stimulation for in vitro fertilization or intra cytoplasmatic sperm injection necessitates close monitoring using ultrasound and estradiol measurements. Monitoring is also important to prevent or limit the severity of ovarian hyper stimulation syndrome, an iatrogenic and potentially life-threatening complication. Self-operated endovaginal telemonitoring has been shown to offer an attractive and less costly alternative to classic consultation and saliva estradiol measurements could be a stress-free and practical alternative to serial blood determinations. Objectives were to evaluate whether saliva can be a surrogate marker for serum estradiol and its potential applicability in assisted reproduction treatment monitoring. Material and methodsSerial blood and saliva samples were collected from 31 patients undergoing ovarian hyper-stimulation. All patients were followed-up using in-house serial vaginal sonograms and immunoassay serum estradiol measurements. Afterwards estradiol was determined in saliva and serum by LC-MS/MS. For a subset equilibrium dialysis and measurement of free serum estradiol was performed. ResultsAbout 1% of estradiol is present in serum in its free, unbound, form. Salivary estradiol correlates well to both serum free estradiol and serum total estradiol (r=0.80). The concentration of salivary estradiol corresponds to the unbound concentration in serum. The dynamics observed in serum monitoring during treatment are closely mimicked in saliva. ROC analysis on the current limited dataset suggested a saliva cut-off of 22pg/mL (81pmol/L) could help predict risk for OHSS. ConclusionsSalivary E2 can be considered a surrogate marker for free serum estradiol and total serum estradiol in assisted reproduction treatment. Additionally there might be a role as a prediction marker for OHSS although this finding has to be validated in larger datasets.

Serum free estradiol and estrogen receptor-α mediated activity are related to decreased incident hip fractures in older women

There is paucity of data from Asian women on the association between serum estrogens and osteoporotic hip fracture risk. We conducted a case–control study nested within a population-based prospective cohort, The Singapore Chinese Health Study, to evaluate serum estrogens levels, ERα-mediated estrogenic activity and hip fracture risk in postmenopausal Asian women. Among 35,298 women who were recruited between 1993 and 1998, 15,410 women donated blood for research between 1999 and 2004. From this subcohort, we identified 140 cases who subsequently suffered hip fracture after blood donation, and 278 age-matched controls. Serum levels of total estrone, estradiol and sex hormone binding globulin levels were measured in a blinded fashion among cases and controls. ERα-mediated estrogenic activity of serum samples was quantified using a sensitive ERα-driven cell bioassay. Women with hip fracture had lower serum estrogens than control women. Compared to the lowest quintile, women in the highest quintile of free estradiol exhibited a statistically significant 57% reduction in risk of hip fracture (95% confidence interval (CI), 6–80%), with a dose-dependent relationship (p for trend=0.021). High levels of ERα-mediated estrogenic activity were also associated with decreased risk of hip fracture (p for trend=0.048). Overall, women with relatively high levels of both free estradiol and ERα-mediated estrogenic activity had a 55% reduction in hip fracture risk (95% CI, 17–76%) compared to women with low levels of both. High levels of free estradiol and ERα-mediated estrogen activity in sera were associated with reduced hip fracture risk in Chinese postmenopausal women.

Direct measurement of free estradiol in human serum by equilibrium dialysis–liquid chromatography–tandem mass spectrometry and reference intervals of free estradiol in women

BackgroundMeasurement of free estradiol offers a better representation of the bioactive fraction of the hormone. We describe a direct equilibrium dialysis–liquid chromatography–tandem mass spectrometry (ED–LC–MS/MS) method for serum free estradiol. MethodsTwo hundred fifty microliter aliquots of serum were dialyzed for 22h followed by liquid–liquid extraction and derivatization with dansyl chloride. Free estradiol was measured using LC–MS/MS with an AB SCIEX 5500 mass spectrometer in positive ion and multiple reaction monitoring (MRM) mode. ResultsThe limits of detection and quantification for free estradiol were 0.25 and 0.5pg/ml (0.9 and 1.8pmol/l) respectively. Total imprecision was less than 10%. Results of method comparison showed 3 times overestimation using indirect methods of measurement. Reference intervals in pre-menopausal women in follicular, mid-cycle, and luteal phases of cycle were <2.4, <3.1 and <2.6pg/ml (8.8, 11.4, 9.5pmol/l) respectively; in post menopausal women the concentrations were ≤0.5pg/ml (1.8pmol/l). ConclusionsED–LC–MS/MS is a direct method for accurately measuring free estradiol, independent of total estradiol or sex hormone binding globulin concentrations. Imprecision and sensitivity of the method are adequate for clinical diagnostic applications. The degree of variation observed in the method comparison reinforces the relevance of method specific reference ranges.

Relationship between Serum Levels of Sex Hormones and Progression of Subclinical Atherosclerosis in Postmenopausal Women

Postmenopausal hormone therapy has been examined extensively in relation to cardiovascular disease. However, research relating serum levels of sex hormones to cardiovascular disease is sparse, and the results are inconclusive. We measured sex hormones in longitudinally collected samples of 180 postmenopausal women, 91 randomized to 17beta-estradiol and 89 to placebo, in the Estrogen in the Prevention of Atherosclerosis Trial. Repeated measures of sex hormone levels were tested for an association with carotid artery intima-media thickness (CIMT), which was also assessed longitudinally over 2 yr. In all women, changes in serum estrone (P = 0.02), total estradiol (P = 0.01), free estradiol (P = 0.02), and SHBG (P = 0.005) were significantly inversely associated with CIMT progression, controlling for age and body mass index. All the estrogen compounds and SHBG were significantly inversely related with low-density lipoprotein cholesterol and positively associated with high-density lipoprotein cholesterol (all P < 0.0001), whereas free testosterone was positively related with low-density lipoprotein cholesterol and inversely associated with high-density lipoprotein cholesterol (P < 0.003). Despite an increase in serum-free estradiol with estradiol therapy, women with unchanged SHBG and free testosterone levels had an average (se) progression in CIMT of 8.53 (4.72) microm/yr, whereas women with increased free estradiol and SHBG and decreased free testosterone had the largest reduction in CIMT progression [-5.45 (2.77) microm/yr; trend P = 0.03]. Estrogen and SHBG are associated with reduced subclinical atherosclerosis progression in healthy postmenopausal women. These associations are partially mediated by their beneficial effects on lipids. Among women taking estradiol, the most beneficial hormone profile for CIMT progression was increased free estradiol and SHBG with concomitant decreased free testosterone.

Serum-free estradiol (E2) levels are prognostic in men with chemotherapy-naive advanced non-small cell lung cancer (NSCLC) and performance status (PS) 2

7683 Background: In women with advanced NSCLC, premenopausal estradiol levels are associated with a worse survival than postmenopausal levels, suggesting an adverse effect of estradiol on prognosis in NSCLC (JCO 2006, 24(18S):7038; JCO 2006, 24:59–63). Levels of E2, produced from testosterone by aromatase, are often higher in men than in postmenopausal women (Ann Intern Med. 2000, 133:951–63). To investigate the effect of E2 on prognosis in male patients (pts) with advanced NSCLC, total and free E2 levels were assayed in pretreatment samples from men participating in 2 randomized phase III studies, STELLAR 3 and 4. Methods: Free serum E2 levels were measured prior to chemotherapy using a radioimmuno-assay in samples from 289/307 male pts with advanced NSCLC and PS2 enrolled in STELLAR 3 (paclitaxel + carboplatin (C) v. paclitaxel poliglumex (PPX) + C) and STELLAR 4 (vinorelbine or gemcitabine v. PPX). The effect of free E2 levels on survival was evaluated by log rank test. Male pts were categorized as high or low E2 based on values above or below the median (0.42 pg/ml; range: 0.1–2.95).The assay range for normal men is 0.2 - 0.5 pg/ml; in pre- and postmenopausal women, the range is 0.80- 3.45 and 0.12 - 0.39 pg/ml, respectively. Results: Hazard ratio's (HR), median, and 1-yr survival are summarized in the table . Survival was worse for male pts with E2 values higher than the median compared to those below the median (HR 1.56, p = .0008). This difference in survival was not dependent on treatment arm as survival was similar for male pts &gt; 0.42 pg/ml receiving either PPX or control. Conclusions: High serum free E2 levels are associated with shorter survival in men with advanced NSCLC, consistent with the shorter survival noted in NSCLC in premenopausal compared to older women. While PPX is associated with improved survival in women with premenopausal E2 levels (JCO 2006, 24(18S):7039), the relatively low levels of E2 in men may be insufficient to affect survival in male pts receiving PPX. [Table: see text] [Table: see text]

Free Testosterone Is a Positive, Whereas Free Estradiol Is a Negative, Predictor of Cortical Bone Size in Young Swedish Men: The GOOD Study

In this study, we evaluated the predictive roles of sex steroids for skeletal parameters in young men (n = 1068) at the age of peak bone mass. Serum free estradiol was a negative predictor, whereas free testosterone and SHBG were positive predictors of cortical bone size. Previous studies have shown that free estradiol in serum is an independent predictor of areal BMD (aBMD) in elderly men. The aim of this study was to determine whether sex steroids are predictors of volumetric BMD (vBMD) and/or size of the trabecular and cortical bone compartments in young men at the age of peak bone mass. The Gothenburg Osteoporosis and Obesity Determinants (GOOD) study consists of 1068 men, 18.9 +/- 0.6 years of age. Serum levels of testosterone, estradiol, and sex hormone binding globulin (SHBG) were measured, and free levels of testosterone and estradiol were calculated. The size of the cortical bone and the cortical and trabecular vBMDs were measured by pQCT. Regression models including age, height, weight, free estradiol, and free testosterone showed that free estradiol was an independent negative predictor of cortical cross-sectional area (tibia beta = -0.111, p < 0.001; radius beta = -0.125, p < 0.001), periosteal circumference, and endosteal circumference, whereas it was a positive independent predictor of cortical vBMD (tibia beta = 0.100, p < 0.003; radius beta = 0.115, p = 0.001) in both the tibia and radius. Free testosterone was an independent positive predictor of cortical cross-sectional area (tibia beta = 0.071, p = 0.013; radius beta = 0.064, p = 0.039), periosteal circumference, and endosteal circumference in both the tibia and radius. Neither cortical nor trabecular vBMD was associated with free testosterone. SHBG was an independent positive predictor of parameters reflecting the size of the cortical bone, including cross-sectional area (beta = 0.078, p = 0.009), periosteal circumference, and endosteal circumference. Free estradiol is a negative, whereas free testosterone is a positive, predictor of cortical bone size in young men at the age of peak bone mass. These findings support the notion that estrogens reduce, whereas androgens increase, cortical bone size, resulting in the well-known sexual dimorphism of cortical bone geometry.

The relation of the Xbal and Pvull polymorphisms of the estrogen receptor gene and the CAG repeat polymorphism of the androgen receptor gene to peak bone mass and bone turnover rate among young healthy men

The genes coding for estrogen receptor-alpha (ER-alpha) and androgen receptors (AR) are potential candidates for the regulation of bone mass and turnover, which may contribute to both the achievement of peak bone mass and bone loss after completion of growth. The present study was aimed at elucidating the role of two restriction fragment lengths (XbaI and PvuII) polymorphisms of the ER gene and the CAG repeat polymorphism of the AR gene as determinants of peak bone mass in men; special attention was paid to the interaction between serum free estradiol (E2) levels and the XbaI and PvuII genotypes. A cross-sectional study, with data on lifestyle factors collected retrospectively, was performed in 234 young men, aged 18.3 to 20.6 years. Of the men, 184 were recruits of the Finnish Army and 50 were men of similar age who had postponed their military service for reasons not related to health. Bone mineral content (BMC), density (BMD) and scan area were measured in the lumbar spine and upper femur by dual-energy X-ray absorptiometry (DXA). The bone turnover rate was assessed by measuring serum type I procollagen aminoterminal propeptide (PINP) and tartrate-resistant acid phosphatase 5b (TRACP5b) as well as urinary excretion of type I collagen aminoterminal telopeptide (NTX). After adjusting for age, height, weight, exercise, smoking, calcium and alcohol intake, BMC, scan area and BMD at all measurement sites were similar for the different XbaI and PvuII genotypes of the ER and independent of the number of the CAG repeats of the AR gene. No association was found between free E2 levels and bone parameters among any genotype group of the XbaI and PvuII polymorphisms. Except for urinary NTX, which showed a tendency to higher values for the xx (P=0.08) and pp (P=0.10) genotypes of the ER, bone turnover markers were not related to the genotypes studied. Our study does not support the view that the XbaI and PvuII polymorphisms of the ER gene and the CAG polymorphism of the AR gene would have a substantial impact on the development of peak bone mass in young Finnish men.

Inverse association between bone turnover rate and bone mineral density in community-dwelling men >70 years of age: no major role of sex steroid status

Bone loss is accelerated in elderly men. Little is known about the pathophysiology of senile bone loss or about the role played by relative sex steroid deficiency in the determination of bone turnover in elderly men. In a population-based sample of 283 healthy, ambulatory men, aged 71–86 years, we sought to determine whether lower bone mineral density (BMD; using dual-energy X ray absorptiometry at the hip and the forearm) is associated with higher bone turnover, and we assessed the impact of sex steroid status on bone turnover. Indices of bone formation, serum osteocalcin (s-Oc), and bone-specific alkaline phosphatase (s-bAP) and indices of bone resorption, serum and urinary telopeptide of type I collagen (s-CTx and u-CTx), and urinary free deoxypyridinoline (u-Dpd) were intercorrelated ( r = 0.29–0.76, p < 0.001). Bone turnover indices were negatively associated with BMD ( r = −0.17 to −0.34, p < 0.01). In univariate analyses, there was a trend toward weak negative associations of bone turnover markers with serum free testosterone (FT), significant only for s-Oc and s-CTx ( r = −0.16 and −0.14, p < 0.01), and with serum free estradiol (FE 2), significant only for u-CTx and s-CTx ( r = −0.18 and −0.19; p < 0.01). The lower quartile for FE 2 was associated with higher values of u-CTx ( p = 0.003) and s-CTx ( p < 0.001). However, in multivariate models, for the individual markers of bone turnover a negative association between estradiol (E 2) or FE 2 and s-CTx was the only remaining (marginally) significant association ( p < 0.05) for the relationship between sex steroids and any of the bone turnover indices assessed. In community-dwelling men age >70 years, bone turnover rate, as determined by biochemical markers, is a significant negative determinant of prevalent BMD. However, the findings do not support the view that relative differences in sex steroid status, as observed among healthy elderly men, have a major impact on bone turnover.

Effects of Oral and Transdermal Estrogen Replacement Therapy on Markers of Coagulation, Fibrinolysis, Inflammation and Serum Lipids and Lipoproteins in Postmenopausal Women

We compared the effects of oral estradiol (2 mg), transdermal estradiol (50 microg), and placebo on measures of coagulation, fibrinolysis, inflammation and serum lipids and lipoproteins in 27 postmenopausal women at baseline and after 2 and 12 weeks of treatment. Oral and transdermal estradiol induced similar increases in serum free estradiol concentrations. Oral therapy increased the plasma concentrations of factor VII antigen (FVIIag) and activated factor VII (FVIIa), and the plasma concentration of the prothrombin activation marker prothrombin fragment 1+2 (F1+2). Oral but not transdermal estradiol therapy significantly lowered plasma plasminogen activator inhibitor-1 (PAI-1) antigen and tissue-type plasminogen activator (tPA) antigen concentrations and PAI-1 activity, and increased D-dimer concentrations, suggesting increased fibrinolysis. The concentration of soluble E-selectin decreased and serum C-reactive protein (CRP) increased significantly in the oral but not in the transdermal or placebo groups. In the oral but not in the transdermal or placebo estradiol groups low-density-lipoprotein (LDL) cholesterol, apolipoprotein B and lipoprotein (a) concentrations decreased while high-density-lipoprotein (HDL) cholesterol, apolipoprotein AI and apolipoprotein All concentrations increased significantly. LDL particle size remained unchanged. In summary, oral estradiol increased markers of fibrinolytic activity, decreased serum soluble E-selectin levels and induced potentially antiatherogenic changes in lipids and lipoproteins. In contrast to these beneficial effects, oral estradiol changed markers of coagulation towards hypercoagulability, and increased serum CRP concentrations. Transdermal estradiol or placebo had no effects on any of these parameters. These data demonstrate that oral estradiol does not have uniformly beneficial effects on cardiovascular risk markers and that the oral route of estradiol administration rather than the circulating free estradiol concentration is critical for any changes to be observed.

Treatment of isolated hypogonadotropic hypogonadism effect on bone mineral density and bone turnover.

Isolated hypogonadotropic hypogonadism (IHH) presents with delayed puberty in the late teens or early twenties, with a period of testosterone deficiency during active growth. The aims of the study were to determine 1) whether long term treatment of IHH results in normalization of bone density (BMD) and bone turnover, and 2) whether BMD and bone turnover respond to increasing doses of hCG. We studied 10 men, aged 26-46 yr, with IHH who were treated with hCG or testosterone esters (Sustanon) for 2-22 yr, with age at the start of treatment between 17-29 yr, and 10 age- and body weight-matched normal men as a control group. At baseline, lumbar spine, femoral neck, trochanter, and Ward's triangle BMD values were decreased, and serum bone Gla-protein, bone alkaline phosphatase, and urinary pyridinoline, deoxypyridinoline, and N-terminal telopeptide of type I collagen were increased compared with control values (by paired t test, P = 0.02, 0.03, 0.01, 0.05, 0.002, 0.02, 0.02, 0.007, and 0.006, respectively). The age at initial therapy was significantly correlated with total body BMD (r = -0.73; P = 0.017) and lumbar spine BMD (r = -0.756; P = 0.0097). Serum free testosterone was correlated with total body and trochanter BMD (r = 0.635; P = 0.048 and r = 0.629; P = 0.05), and serum free estradiol was correlated with total body and trochanter BMD (r = 0.641; P = 0.045 and r = 0.634; P = 0.048). Six of the 10 patients were recruited for a longitudinal study in which the dose of hCG was increased monthly from 2000 i.u. twice per week to 6000 i.u. twice per week. After increasing doses of hCG, levels of serum testosterone and estradiol and total body BMD increased significantly (by paired t test P = 0.001, 0.003, and 0.01, respectively). Serum bone Gla-protein levels increased by the first month and then decreased (paired t test, corrected by Bonferroni's method). Serum bone alkaline phosphatase and urinary N-terminal telopeptide of type I collagen/creatinine levels decreased significantly after increasing the dose of hCG. We conclude that patients with IHH who have serum testosterone within the laboratory reference range may require a higher dose of hCG to normalize BMD and bone turnover.

Relationships of serum lipoproteins and apoproteins to sex hormones and to the binding capacity of sex hormone binding globulin in healthy finnish men

We have determined the levels of serum sex hormones, the binding capacity of sex hormone binding globulin (SHBG), urinary estrogens, serum lipids, lipoproteins, and apolipoproteins A-I, A-II, and B in 30 healthy middle-aged Finnish men with similar dietary habits. Serum levels of total testosterone, free testosterone, 5α-dihydrotestosterone (5α-DHT), and the binding capacity of SHBG were all positively correlated to high density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (apo A-I) ( r = .43 to .80, P < 0.05 to 0.001). Total testosterone and 5α-DHT showed a positive correlation to the ratio of apo A-I to Apo A-II ( r = .37, P < 0.05 and r = .58, P < 0.01, respectively). Serum estradiol levels were negatively correlated to serum total cholesterol, low density lipoprotein cholesterol (LDL), and Apo B ( r = −.51 to −.56, P < 0.01). Moreover, serum free estradiol was negatively correlated to HDL-C and Apo A-I ( r = −.46 and r = −.50, P < 0.01). In multiple linear regression analysis, 5α-DHT was the most significant independent determinant of HDL-C and apo A-I levels when androgens, luteinizing hormone, estradiol, binding capacity of SHBG, and exogenous factors such as age, body mass index (BMI), smoking, alcohol consumption, and diet were taken into account. Multivariate analysis also demonstrated that both total and free estradiol were inversely related to serum Apo B levels. Our results demonstrate that in healthy men the concentrations of serum lipoprotein cholesterol and apolipoproteins, especially HDL-C and apo A-I, are influenced by the sex hormone status. The metabolic mechanisms and their possible association with the risk of coronary heart disease warrants further study.