Discrepancy between radioimmunoassay and high performance liquid chromatography tandem-mass spectrometry for the analysis of androstenedione

Report from the HarmoSter study: different LC-MS/MS androstenedione, DHEAS and testosterone methods compare well; however, unifying calibration is a double-edged sword

OBJECTIVES

Current liquid chromatography-tandem mass spectrometry (LC-MS/MS) applications for circulating androgen measurements are technically diverse. Previously, variable results have been reported for testosterone. Data are scarce for androstenedione and absent for dehydroepiandrosterone sulfate (DHEAS). We assessed the agreement of androstenedione, DHEAS and testosterone LC-MS/MS measurements among nine European centers and explored benefits of calibration system unification.

METHODS

Androgens were measured twice by laboratory-specific procedures in 78 patient samples and in EQA materials. Results were obtained by in-house and external calibration. Intra- and inter-laboratory performances were valued.

RESULTS

Intra-laboratory CVs ranged between 4.2-13.2 % for androstenedione, 1.6-10.8 % for DHEAS, and 4.3-8.7 % and 2.6-7.1 % for female and male testosterone, respectively. Bias and trueness in EQA materials were within ±20 %. Median inter-laboratory CV with in-house vs. external calibration were 12.0 vs. 9.6 % for androstenedione (p<0.001), 7.2 vs. 4.9 % for DHEAS (p<0.001), 6.4 vs. 7.6 % for female testosterone (p<0.001) and 6.8 and 7.4 % for male testosterone (p=0.111). Median bias vs. all laboratory median with in-house and external calibration were -13.3 to 20.5 % and -4.9 to 18.7 % for androstenedione, -10.9 to 4.8 % and -3.4 to 3.5 % for DHEAS, -2.7 to 6.5 % and -11.3 to 6.6 % for testosterone in females, and -7.0 to 8.5 % and -7.5 to 11.8 % for testosterone in males, respectively.

CONCLUSIONS

Methods showed high intra-laboratory precision but variable bias and trueness. Inter-laboratory agreement was remarkably good. Calibration system unification improved agreement in androstenedione and DHEAS, but not in testosterone measurements. Multiple components, such as commutability of calibrators and EQA materials and internal standard choices, likely contribute to inter-laboratory variability.

Synthesis of molecularly-imprinted polymers towards a group of amphetamine-type stimulants by reflux precipitation polymerization with a pseudo template

Determination of amphetamine-type drugs (ATSs) in urine and wastewater is a simplified approach for the widespread monitoring of ATSs abuse. To improve the sensitivity of the analytical methods, molecularly imprinted polymers (MIPs) based solid-phase extraction (SPE) pretreatment attracted great attention in this field. Generally, smaller particle sizes and more uniform morphology of the MIPs could provide higher detection sensitivity. Our previous works showed reflux precipitation polymerization (RPP) is a method for synthesizing monodispersed MIPs with small particle size. However, synthesis of uniform spherical MIPs towards a group of targets has never been reported. Therefore, in the present work, MIPs towards a group of ATSs were synthesized via RPP with a pseudo template for the first time. After screening potential pseudo-templates, N-methylphenylethylamine (MPEA) was selected as the optimal pseudo-template. MPEA-MIPs were characterized by scanning electron microscope (SEM), FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS) spectra. Adsorption isotherms, adsorption kinetics and selectivity were evaluated, and the experimental results indicated that the MPEA-MIPs possessed good selectivity and adsorption property towards ATSs. After optimization of the MIP-SPE procedure, the MIP-SPE cartridges were then coupled with liquid chromatography and tandem mass spectrometry (LC-MS/MS) for determination of ATSs. The evaluation results showed that MIP-SPE-LC-MS/MS displayed good linearity (R² >0.991) in the linear range (1.0-50.0 µg/L for urine and 0.5-50.0 µg/L for wastewater), and low matrix effect (85-112%). The limit of detection (LOD) was 0.05 -0.29 µg/L, and the accuracy (85-115%) and repeatability (RSD ≤ 15%) were satisfactory at low, medium and high concentrations. To the best of our knowledge, this is the first time that dummy MIPs towards a group of ATSs were synthesized by RPP polymerization, which showed great potential for the detection of ATSs in urine and wastewater.

Mass spectrometry-based cortisol profiling during adrenal venous sampling reveals misdiagnosis for subtyping primary aldosteronism

OBJECTIVE

Primary aldosteronism (PA) is a common form of secondary hypertension. Adrenal venous sampling (AVS) is the gold standard for subtyping PA. This study aimed to determine whether there is a difference between immunoassays and liquid chromatography-mass spectrometry (LC-MS/MS) methods for measuring cortisol levels that affect the judgement of AVS.

DESIGN

This was a retrospective study.

PATIENTS

Included 72 patients who were diagnosed with PA and had undergone AVS.

MEASUREMENTS

Patients were grouped according to whether they received adrenocorticotropic hormone (ACTH) stimulation during AVS, and the cortisol results were measured using immunoassay and LC-MS/MS.

RESULTS

There were 48 patients in the without ACTH stimulation group and 24 in the post-ACTH stimulation group during AVS (bilateral adrenal vein cannulation success rate, 56.25% vs. 83.33%). ACTH stimulation was beneficial for increasing the success rate of AVS (p < .001). Immunoassays were linearly correlated with LC-MS/MS when cortisol concentrations were <1750 nmol/L (r = .959, p < .001). When cortisol concentrations were >17,500 nmol/L, no correlation was found between the two methods (p = .093). The two methods were consistent for the detection of cortisol for evaluating the success of cannulation for AVS. Five percent of patients showed discordant lateralization of aldosterone production according to the cortisol LC-MS/MS and immunoassay results in the without ACTH group, and 15% showed discordant lateralization in the post-ACTH group.

CONCLUSIONS

The immunoassay method can be used to determine whether cannulation is successful. The final decision for lateralization may be more appropriate based on LC-MS/MS results.

Report from the HarmoSter study: impact of calibration on comparability of LC-MS/MS measurement of circulating cortisol, 17OH-progesterone and aldosterone

OBJECTIVES

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is recommended for measuring circulating steroids. However, assays display technical heterogeneity. So far, reproducibility of corticosteroid LC-MS/MS measurements has received scant attention. The aim of the study was to compare LC-MS/MS measurements of cortisol, 17OH-progesterone and aldosterone from nine European centers and assess performance according to external quality assessment (EQA) materials and calibration.

METHODS

Seventy-eight patient samples, EQA materials and two commercial calibration sets were measured twice by laboratory-specific procedures. Results were obtained by in-house (CAL1) and external calibrations (CAL2 and CAL3). We evaluated intra and inter-laboratory imprecision, correlation and agreement in patient samples, and trueness, bias and commutability in EQA materials.

RESULTS

Using CAL1, intra-laboratory CVs ranged between 2.8-7.4%, 4.4-18.0% and 5.2-22.2%, for cortisol, 17OH-progesterone and aldosterone, respectively. Trueness and bias in EQA materials were mostly acceptable, however, inappropriate commutability and target value assignment were highlighted in some cases. CAL2 showed suboptimal accuracy. Median inter-laboratory CVs for cortisol, 17OH-progesterone and aldosterone were 4.9, 11.8 and 13.8% with CAL1 and 3.6, 10.3 and 8.6% with CAL3 (all p<0.001), respectively. Using CAL1, median bias vs. all laboratory-medians ranged from -6.6 to 6.9%, -17.2 to 7.8% and -12.0 to 16.8% for cortisol, 17OH-progesterone and aldosterone, respectively. Regression lines significantly deviated from the best fit for most laboratories. Using CAL3 improved cortisol and 17OH-progesterone between-method bias and correlation.

CONCLUSIONS

Intra-laboratory imprecision and performance with EQA materials were variable. Inter-laboratory performance was mostly within specifications. Although residual variability persists, adopting common traceable calibrators and RMP-determined EQA materials is beneficial for standardization of LC-MS/MS steroid measurements.

Androgens and Development of Posttransplantation Diabetes Mellitus in Male Kidney Transplant Recipients: A Post Hoc Analysis of a Prospective Study

OBJECTIVE

Posttransplantation diabetes mellitus (PTDM) effects up to 30% of all kidney transplant recipients (KTR). Recent studies in mice found that sufficient androgen levels are necessary for β-cell health and adequate insulin secretion. This raises the question whether a similar relationship might be present in KTR. Hence, we hypothesized that dihydrotestosterone and testosterone are associated with the development of PTDM in male KTR.

RESEARCH DESIGN AND METHODS

We conducted a post hoc analyses of a prospective single-center cohort study including adult male KTR with a functioning graft ≥1 year posttransplantation. Androgen levels were assessed by liquid chromatography-tandem mass spectrometry. Development of PTDM was defined according to the American Diabetes Association's criteria.

RESULTS

We included 243 male KTR (aged 51 ± 14 years), with a median dihydrotestosterone 0.9 (0.7-1.3) nmol/L and testosterone of 12.1 (9.4-15.8) nmol/L. During 5.3 (3.7-5.8) years of follow-up, 28 KTR (11.5%) developed PTDM. A clear association was observed, as 15 (19%), 10 (12%), and 3 (4%) male KTR developed PTDM in the respective tertiles of dihydrotestosterone (P = 0.008). In Cox regression analyses, both dihydrotestosterone and testosterone as continuous variables were inversely associated with the risk to development PTDM, independent of glucose and HbA_1c (hazard ratio [HR] 0.31 [95% CI 0.16-0.59], P < 0.001; and HR 0.32 [95% CI 0.15-0.68], P = 0.003, respectively).

CONCLUSIONS

Our results suggest that low androgen levels are a novel potential modifiable risk factor for the development of PTDM in male KTR.

Sex Dimorphism of Nonalcoholic Fatty Liver Disease (NAFLD) in Pparg-Null Mice

Men with nonalcoholic fatty liver disease (NAFLD) are more exposed to nonalcoholic steatohepatitis (NASH) and liver fibrosis than women. However, the underlying molecular mechanisms of NALFD sex dimorphism are unclear. We combined gene expression, histological and lipidomic analyses to systematically compare male and female liver steatosis. We characterized hepatosteatosis in three independent mouse models of NAFLD, ob/ob and lipodystrophic fat-specific (PpargFΔ/Δ) and whole-body PPARγ-null (PpargΔ/Δ) mice. We identified a clear sex dimorphism occurring only in PpargΔ/Δ mice, with females showing macro- and microvesicular hepatosteatosis throughout their entire life, while males had fewer lipid droplets starting from 20 weeks. This sex dimorphism in hepatosteatosis was lost in gonadectomized PpargΔ/Δ mice. Lipidomics revealed hepatic accumulation of short and highly saturated TGs in females, while TGs were enriched in long and unsaturated hydrocarbon chains in males. Strikingly, sex-biased genes were particularly perturbed in both sexes, affecting lipid metabolism, drug metabolism, inflammatory and cellular stress response pathways. Most importantly, we found that the expression of key sex-biased genes was severely affected in all the NAFLD models we tested. Thus, hepatosteatosis strongly affects hepatic sex-biased gene expression. With NAFLD increasing in prevalence, this emphasizes the urgent need to specifically address the consequences of this deregulation in humans.

A high resolution LC-MS targeted method for the concomitant analysis of 11 contraceptive progestins and 4 steroids

In the context of hormonal contraception and hormone replacement therapy (HRT), many women are exposed to exogenous hormones. Current use of hormonal contraception with combined ethinyl estradiol and different progestins bestows a breast cancer relative risk (RR) of 1.2- while combined HRT has a RR of 2. Although these exposures present an important public health issue, little is known about the effects of individual progestins on the breast and other tissues. Increasing availability of large scale biobanks, high throughput analyses and data management tools enable ever expanding, sophisticated population studies. In order to address the impact of distinct progestins on various health indicators, it is desirable to accurately quantify progestins in clinical samples. Here we have developed and validated a high resolution liquid chromatography mass spectrometry (LC-MS) targeted method for the simultaneous quantification of 11 synthetic progestins widely used in oral contraceptives, gestodene, levonorgestrel, etonogestrel, chlormadinone acetate, cyproterone acetate, drospirenone, desacetyl norgestimate, medroxyprogesterone acetate, norethindrone, dienogest, nomegestrol acetate, and 4 endogenous steroid hormones, progesterone, testosterone, androstenedione, and cortisol in blood samples. This highly specific quantitative analysis with high resolution Orbitrap technology detects and quantifies 15 compounds using their internal standard counterparts in a single 12 min LC-MS run. Sensitivity is attained by the use of the instrument in targeted selected ion monitoring mode. Lower limit of quantitation ranges from 2.4 pg/ml for drospirenone to 78.1 pg/ml for chlormadinone acetate. The method provides comprehensive progestin panel measurements with as little as 50 μl of murine or human plasma.

Thigh and abdominal adipose tissue depot associations with testosterone levels in postmenopausal females

OBJECTIVE

Research findings on the relationship between serum androgens and adipose tissue in older females are inconsistent. We aimed to clarify the relationship using state-of-the-art techniques to evaluate associations between body fat distribution and plasma testosterone (T) levels in older postmenopausal women.

DESIGN

Observational, cross-sectional study of healthy, community dwelling postmenopausal women.

PATIENTS AND MEASUREMENTS

Postmenopausal women (60-80 years old) were included in this study. Overall body composition was evaluated by dual-energy X-ray absorptiometry. Abdominal and thigh fat depots were measured by magnetic resonance imaging. Circulating T concentrations were analysed by liquid chromatography-tandem mass spectrometry.

RESULTS

Thirty-five women (66.6 ± 0.8 years) participated in this study. T levels were positively associated with clinical proxy measures of adiposity including weight (ρ = 0.39), BMI (ρ = 0.43) and waist circumference (ρ = 0.39) (all P < 0.05). Fat mass and % body fat were correlated with T levels (ρ = 0.42 and 0.38 respectively, both P < 0.05). T correlated with overall and superficial abdominal fat (ρ = 0.34 and 0.37 respectively, both P < 0.05) but not with visceral adipose tissue. T increased with greater thigh fat (ρ = 0.49, P < 0.05) in both superficial and deep depots (ρ = 0.50 and 0.35 respectively, both P < 0.05).

CONCLUSION

Our results suggest that postmenopausal women with higher circulating T levels have both higher regional and overall body adiposity. These findings underscore the sexual dimorphism in the relationship between serum androgen levels and adiposity.

Oestrogen receptor α AF-1 and AF-2 domains have cell population-specific functions in the mammary epithelium

Oestrogen receptor α (ERα) is a transcription factor with ligand-independent and ligand-dependent activation functions (AF)-1 and -2. Oestrogens control postnatal mammary gland development acting on a subset of mammary epithelial cells (MECs), termed sensor cells, which are ERα-positive by immunohistochemistry (IHC) and secrete paracrine factors, which stimulate ERα-negative responder cells. Here we show that deletion of AF-1 or AF-2 blocks pubertal ductal growth and subsequent development because both are required for expression of essential paracrine mediators. Thirty percent of the luminal cells are ERα-negative by IHC but express Esr1 transcripts. This low level ERα expression through AF-2 is essential for cell expansion during puberty and growth-inhibitory during pregnancy. Cell-intrinsic ERα is not required for cell proliferation nor for secretory differentiation but controls transcript levels of cell motility and cell adhesion genes and a stem cell and epithelial mesenchymal transition (EMT) signature identifying ERα as a key regulator of mammary epithelial cell plasticity.

Oestrogen receptors α (ERα) are expressed in a subset of mammary epithelial cells. Here, the authors identify cells with low-ERα protein levels and show that distinct cell populations have distinct requirements for the AF1 and AF2 domains of the ERα, and ERα acts in a biphasic manner dependent on developmental stage.

Advances in human chorionic gonadotropin detection technologies: a review

Human chorionic gonadotropin (HCG) is a glycoprotein secreted by placental trophoblast cells in pregnancy. HCG is a heterodimer composed of two different α- and β-subunits, with the latter being unique to HCG. As well as being the most important diagnostic markers for pregnancy, HCG is also a tumor marker, therefore, quantitative detection of HCG is of great value. Numerous advanced technologies have been developed for HCG concentration detection including electrochemical immunoassay, chemiluminescent immunoassay, fluorescence immunoassay, resonance scattering spectrometry, atomic emission spectrometry, radioimmunoassay, MS and so on. Some have pursued simple and easy operation, while others have emphasized on accuracy and applications in clinical medicine. This review provides a comprehensive summary of various methods of detecting HCG.

Prospective and Descriptive Study on Serum Androstenedione Concentration in Healthy Children from Birth until 18 Years of Age and Its Associated Factors

Introduction

Androstenedione (A4) is an adrenal and gonadal steroid biomarker, useful in the assessment of children in whom steroidogenic disorders are suspected. The first key step in the evaluation of a diagnostic test resides on confident reference intervals (RI). The lack of updated A4-RI with current methods in pediatrics may mislead A4 results and limit its diagnosis accuracy.

Aim

To provide A4 reference ranges in healthy children.

Methods

Prospective, descriptive study. 283 children aged 4 days to 18 years were included. In children < 1 yr, A4 was measured directly in serum (NE-A4) and postorganic solvent extraction (E-A4) for the assessment of interfering steroids. The influence of chronological age (CA), gender, and Tanner stage (T) were investigated.

Results

In the neonatal period, E-A4 was significantly lower than NE-A4; boys had higher NE-A4; sexual dimorphism disappeared after extraction procedure. In children older than 4 months, A4 concentration remained low until the age of 5 years. Thereafter, A4 increased significantly in association with CA and T (r² = 0.65; p < 0.001), obtaining the highest concentrations in children within pubertal ages without sexual dimorphism.

Conclusion

We recommend to perform solvent extraction in neonates and to take into account age and sexual development to properly interpret A4 results in childhood.

Reference intervals for plasma concentrations of adrenal steroids measured by LC-MS/MS: Impact of gender, age, oral contraceptives, body mass index and blood pressure status

Background

Mass spectrometric-based measurements of the steroid metabolome have been introduced to diagnose disorders featuring abnormal steroidogenesis. Defined reference intervals are important for interpreting such data.

Methods

Liquid chromatography–tandem mass spectrometry was used to establish reference intervals for 16 steroids (pregnenolone, progesterone, 11-deoxycorticosterone, corticosterone, aldosterone, 18-oxocortisol, 18-hydroxycortisol, 17-hydroxyprogesterone, 21-deoxycortisol, 11-deoxycortisol, cortisol, cortisone, dehydroepiandrosterone, dehydroepiandrosterone-sulfate, androstenedione, testosterone) measured in plasma from 525 volunteers with (n = 227) and without (n = 298) hypertension, including 68 women on oral contraceptives.

Results

Women showed variable plasma concentrations of several steroids associated with menstrual cycle phase, menopause and oral contraceptive use. Progesterone was higher in females than males, but most other steroids were higher in males than females and almost all declined with advancing age. Using models that corrected for age and gender, body mass index showed weak negative relationships with corticosterone, 21-deoxycortisol, cortisol, cortisone, testosterone, progesterone, 17-hydroxyprogesterone and 11-deoxycorticosterone, but a positive relationship with 18-hydroxycortisol. Hypertensives and normotensives showed negligible differences in plasma concentrations of steroids.

Conclusion

Age and gender are the most important variables for plasma steroid reference intervals, which have been established here according to those variables for a panel of 16 steroids primarily useful for diagnosis and subtyping of patients with endocrine hypertension.

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Reference intervals established for LC-MS/MS-measurements of 16 plasma steroids

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Reference population consisted of 525 normotensive and hypertensive volunteers.

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Age and gender were the most important variables to consider for reference intervals.

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Weak negative associations of several steroids with body mass index

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Negligible associations of plasma steroids with blood pressure status

Mass Spectrometry-Based Adrenal and Peripheral Venous Steroid Profiling for Subtyping Primary Aldosteronism

BACKGROUND

Differentiating patients with primary aldosteronism caused by aldosterone-producing adenomas (APAs) from those with bilateral adrenal hyperplasia (BAH), which is essential for choice of therapeutic intervention, relies on adrenal venous sampling (AVS)-based measurements of aldosterone and cortisol. We assessed the utility of LC-MS/MS-based steroid profiling to stratify patients with primary aldosteronism.

METHODS

Fifteen adrenal steroids were measured by LC-MS/MS in peripheral and adrenal venous plasma from AVS studies for 216 patients with primary aldosteronism at 3 tertiary referral centers. Ninety patients were diagnosed with BAH and 126 with APAs on the basis of immunoassay-derived adrenal venous aldosterone lateralization ratios.

RESULTS

Among 119 patients confirmed to have APAs at follow-up, LC-MS/MS-derived lateralization ratios of aldosterone normalized to cortisol, dehydroepiandrosterone, and androstenedione were all higher (P < 0.0001) than immunoassay-derived ratios. The hybrid steroids, 18-oxocortisol and 18-hydroxycortisol, also showed lateralized secretion in 76% and 35% of patients with APAs. Adrenal venous concentrations of glucocorticoids and androgens were bilaterally higher in patients with BAH than in those with APAs. Consequently, peripheral plasma concentrations of 18-oxocortisol were 8.5-fold higher, whereas concentrations of cortisol, corticosterone, and dehydroepiandrosterone were lower in patients with APAs than in those with BAH. Correct classification of 80% of cases of APAs vs BAH was thereby possible by use of a combination of steroids in peripheral plasma.

CONCLUSIONS

LC-MS/MS-based steroid profiling during AVS achieves higher aldosterone lateralization ratios in patients with APAs than immunoassay. LC-MS/MS also enables multiple measures for discriminating unilateral from bilateral aldosterone excess, with potential use of peripheral plasma for subtype classification.

Content of deuterium in biological fluids and organs: Influence of deuterium depleted water on D/H gradient and the process of adaptation

It is found that consumption of deuterium depleted water reduces not only the content of deuterium in biological fluids but also more than 2 times reduces the D/H gradient value along the line: mixed saliva > blood plasma. The experimental data showed that a physiological solution prepared on deuterium depleted water during induced apoptosis activates the DNA repair system, significantly reducing the number of single-stranded DNA breaks, which, in general, indicates an increase in the efficiency of defensive systems of the cell.