Measurement of serum steroid profiles by HPLC-tandem mass spectrometry

Facile immobilization of cholesterol oxidase on Pt,Ru-C nanocomposite and ionic liquid-modified carbon paste electrode for an efficient amperometric free cholesterol biosensing

In present work, the enzyme cholesterol oxidase (ChOx) was immobilized by Nafion® (Naf) on Pt,Ru-C nanocomposite and an ionic liquid (IL)-modified carbon paste electrode (CPE) in order to create cholesterol biosensor (Naf/ChOx/Pt,Ru-C/IL-CPE). The prepared working electrodes were characterized using scanning electron microscopy-energy-dispersive spectrometry, while their electrochemical performance was evaluated using electrochemical impedance spectroscopic, cyclic voltammetric, and amperometric techniques. Excellent synergism between IL 1-allyl-3-methylimidazolium dicyanamide ([AMIM][DCA]), Pt,Ru-C, and ChOx, as modifiers of CPE, offers the most pronounced analytical performance for improved cholesterol amperometric determination in phosphate buffer solution pH 7.50 at a working potential of 0.60 V. Under optimized experimental conditions, a linear relationship between oxidation current and cholesterol concentration was found for the range from 0.31 to 2.46 µM, with an estimated detection limit of 0.13 µM and relative standard deviation (RSD) below 5.5%. The optimized amperometric method in combination with the developed Naf/ChOx/Pt,Ru-C/IL-CPE biosensor showed good repeatability and high selectivity towards cholesterol biosensing. The proposed biosensor was successfully applied to determine free cholesterol in a human blood serum sample via its enzymatic reaction product hydrogen peroxide despite the presence of possible interferences. The percentage recovery ranged from 99.08 to 102.81%, while RSD was below 2.0% for the unspiked as well as the spiked human blood serum sample. The obtained results indicated excellent accuracy and precision of the method, concluding that the developed biosensor can be a promising alternative to existing commercial cholesterol tests used in medical practice.

Determination of steroid hormones in grey seal (Halichoerus grypus) blood plasma using convergence chromatography tandem mass spectrometry

A hybrid solid phase extraction (HybridSPE) protocol tailored to ultra-performance convergence chromatography tandem mass spectrometry (UPC²-MS/MS) was developed for the determination of 19 steroid hormones in grey seal (Halichoerus grypus) blood plasma. In this study, the protocol demonstrated acceptable absolute recoveries ranging from 33 to 90%. The chromatographic separation was carried out using a gradient elution program with a total run time of 5 min. For most target analytes, the method repeatability ranged from 1.9 to 24% and the method limits of quantification (mLOQs) ranged from 0.03 to 1.67 ng/mL. A total of 9 plasma samples were analysed to demonstrate the applicability of the developed method, and 13 steroid hormones were quantified in grey seal pup plasma. The most prevalent steroids: cortisol, cortisone, corticosterone, 11-deoxycortisol, progesterone and 17α-hydroxyprogesterone were detected at concentrations in the range of 12.6-40.1, 7.10-24.2, 0.74-10.7, 1.06-5.72, 0.38-4.38 and <mLOQ - 1.01 ng/mL, respectively. To our knowledge, this is the first study to determine steroid hormones in the plasma of pinnipeds using convergence chromatography.

A New Heart-Cutting Method for a Multiplex Quantitative Analysis of Steroid Hormones in Plasma Using 2D-LC/MS/MS Technique

The aim of the current research was to develop a simple and rapid mass spectrometry-based assay for the determination of 15 steroid hormones in human plasma in a single run, which would be suitable for a routine practice setting. For this purpose, we designed a procedure based on the 2D-liquid chromatography-tandem mass spectrometry with a minimalistic sample pre-treatment. In our arrangement, the preparation of one sample takes only 10 min and can accommodate 40 samples per hour when tested in series. The following analytical run is 18 min long for all steroid hormones. In addition, we developed an independent analytical run for estradiol, significantly increasing the assay accuracy while taking an additional 10 min to perform an analytical run of a sample. The optimized method was applied to a set of human plasma samples, including chylous. Our results indicate the linearity of the method for all steroid hormones with squared regression coefficients R² ≥ 0.995, within-run and between-run precision (RSD < 6.4%), and an accuracy of 92.9% to 106.2%. The absolute recovery for each analyzed steroid hormone ranged between 101.6% and 116.5%. The method detection limit for 15 steroid hormones ranged between 0.008 nmol/L (2.88 pg/mL) for aldosterone and 0.873 nmol/L (0.252 ng/mL) for DHEA. For all the analytes, the lowest calibration point relative standard deviation was less than 10.8%, indicating a good precision of the assay within the lowest concentration of interest. In conclusion, in this method article, we describe a simple, sensitive, and cost-effective 2D-LC/MS/MS method suitable for the routine analysis of a complex of steroid hormones allowing high analytical specificity and sensitivity despite minimal sample processing and short throughput times.

Clinical Usefulness of Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Method for Low Serum Testosterone Measurement

Background

Mass spectrometry methods exhibit higher accuracy and lower variability than immunoassays at low testosterone concentrations. We developed and validated an ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay for quantifying serum total testosterone.

Methods

We used an ExionLC UPLC (Sciex, Framingham, MA, USA) system and a Sciex Triple Quad 6500+ (Sciex) MS/MS system in electrospray ionization and positive ion modes with multiple reaction monitoring transitions to evaluate precision, accuracy, linearity, lower limit of quantitation (LLOQ), carryover, ion suppression, stability, and reference intervals. For method comparison, we measured serum testosterone concentrations using this method in 40 subjects whose testosterone concentrations ranged from 0.14 to 55.48 nmol/L as determined using the Architect i2000 immunoassay (Abbott Diagnostics, Abbott Park, IL, USA) and in an additional 160 sera with testosterone concentrations <1.67 nmol/L.

Results

The intra- and inter-run precision CVs were <2.81%, and the accuracy bias values were <3.85%, which were all acceptable. The verified linear interval was 0.03-180.84 nmol/L; the LLOQ was 0.03 nmol/L. No significant carryover and ion suppression were observed. The testosterone in serum was stable at 4°C, at -20°C, and after three freeze-thaw cycles. The reference intervals were successfully verified. The correlation was good at testosterone concentrations of 0.14-55.48 nmol/L; however, the Architect assay showed positive percent bias at concentrations <1.67 nmol/L.

Conclusions

The UPLC-MS/MS assay shows acceptable performance, with a lower LLOQ than the immunoassay. This method will enable the quantitation of low testosterone concentrations.

Design and Validation of a Sensitive Multisteroid LC-MS/MS Assay for the Routine Clinical Use: One-Step Sample Preparation with Phospholipid Removal and Comparison to Immunoassays

Steroid analysis in clinical laboratories is dominated by immunoassays (IAs) that have a high sample turnover but are inherently limited in trueness, precision, and sensitivity. Liquid chromatography coupled to mass spectrometry (LC-MS/MS) has proved to be a far more capable tool, delivering better sensitivity, specificity, and the possibility of parallel analysis of multiple steroids and metabolites, providing the endocrinologist with more reliable and comprehensive diagnostic information. An LC-MS/MS assay with gradient elution over less than eight minutes and a one-step sample preparation combining protein precipitation with phospholipid removal of off-line solid-phase extraction was developed and validated. It allowed the quantification of 11-deoxycorticosterone (11-DOC), 11-deoxycortisol (11-DF), 17-OH-progesterone (17P), 21-deoxycortisol (21-DF), androstenedione (ANDRO), aldosterone (ALDO), corticosterone (CC), cortisol (CL), cortisone (CN), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), dihydrotestosterone (DHT), estradiol (E2), progesterone (PROG), and testosterone (TES) in human serum. Interday imprecision was generally better than 15%, trueness was proven by recovery experiments with ISO 17034-certified reference materials, proficiency testing (UK NEQAS), and measuring serum reference standards. In-house comparison against IVD-CE-certified immunoassays (IA) for 17P, ANDRO, CL, DHEAS, E2, PROG, and TES was conducted by assessing leftover routine patient samples and purpose-built patient serum pools. None of the compared routine IAs were meeting the standards of the LC-MS/MS. Insufficient overall comparability was found for ANDRO and 17P (mean bias > +65%). Accuracy limitations at lower concentrations were present in IAs for PROG, E2, and TES.

Simultaneous quantitation of 17 endogenous adrenal corticosteroid hormones in human plasma by UHPLC-MS/MS and their application in congenital adrenal hyperplasia screening

Accurate investigation of adrenal hormone levels plays a vital role in pediatric endocrinology for the detection of steroid-related disorders. This study aims to develop a straightforward, sensitive UHPLC-MS/MS method to quantify 17 endogenous adrenal corticosteroid hormones in human plasma. These hormones are the main ingredients in the synthetic and metabolic pathways of adrenal corticosteroid hormones. Chromatographic separation was achieved on a C18 column before electrospray ionization triple-quadrupole mass spectrometry in multiple reaction monitoring mode with a run time of 7 min. The samples were extracted by liquid-liquid extraction and required no derivatization. Analytical performance was evaluated, including linearity, analytical sensitivity, accuracy, precision, and specificity. Plasma specimens from 32 congenital adrenal hyperplasia (CAH) patients and 30 healthy volunteers were analyzed to further reveal the diagnostic value of multiple steroid hormones in the synthetic and metabolic pathways of adrenal corticosteroid in CAH diagnosis. All hormones were effectively extracted and separated using our method. The method was essentially free from potential interference of isomers or structural analogues. The imprecisions were <10%. The lower limits of quantification varied from 0.05 to 15.0 ng/ml. Good linearity coefficients (r² > 0.998) were also obtained for most hormones in the required concentration range, except for 21-deoxycortisol (r² = 0.9967) and androstenediol (r² = 0.9952). The recoveries for the steroid hormones ranged from 91.7 to 109.8%. We developed the UHPLC-MS/MS method for the simultaneous measurement of steroid hormones. The results showed that measurement of steroid hormones simultaneously could improve the diagnostic efficiency of CAH.

Online In-Tube Solid-Phase Microextraction Coupled with Liquid Chromatography-Tandem Mass Spectrometry for Automated Analysis of Four Sulfated Steroid Metabolites in Saliva Samples

Accurate measurement of sulfated steroid metabolite concentrations can not only enable the elucidation of the mechanisms regulating steroid metabolism, but also lead to the diagnosis of various related diseases. The present study describes a simple and sensitive method for the simultaneous determination of four sulfated steroid metabolites in saliva, pregnenolone sulfate (PREGS), dehydroepiandrosterone sulfate (DHEAS), cortisol sulfate (CRTS), and 17β-estradiol-3-sulfate (E2S), by online coupling of in-tube solid-phase microextraction (IT-SPME) and stable isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS). These compounds were extracted and concentrated on Supel-Q PLOT capillary tubes by IT-SPME and separated and detected within 6 min by LC-MS/MS using an InertSustain swift C18 column and negative ion mode multiple reaction monitoring systems. These operations were fully automated by an online program. Calibration curves using their stable isotope-labeled internal standards showed good linearity in the range of 0.01-2 ng mL^-1 for PREGS, DHEAS, and CRTS and of 0.05-10 ng mL^-1 for E2S. The limits of detection (S/N = 3) of PREGS, DHEAS, CRTS, and E2S were 0.59, 0.30, 0.80, and 3.20 pg mL^-1, respectively. Moreover, intraday and interday variations were lower than 11.1% (n = 5). The recoveries of these compounds from saliva samples were in the range of 86.6-112.9%. The developed method is highly sensitive and specific and can easily measure sulfated steroid metabolite concentrations in 50 μL saliva samples.

Using mass spectrometry to overcome the longstanding inaccuracy of a commercially-available clinical testosterone immunoassay

Accurate measurement of testosterone is important for the diagnosis of gonadal disorders in men, women, and children. Testosterone measurement has limited accuracy at low concentrations by most commercially available immunoassays. We aimed to develop an LC-MS/MS assay to address the inaccuracy of the in-house immunoassay observed over the past decade and to replace it with the new assay. Testosterone in serum/plasma was extracted with commercial supported liquid extraction plates. Method validation was performed following the CLSI C62-A guideline. A total of 126 samples were used for method comparison between the Beckman UniCel DxI immunoassay and LC-MS/MS. Results by immunoassay were 20% lower compared with LC-MS/MS and had minimal correlation (R² = 0.403) with LC-MS/MS below 100 ng/dL. When comparing specimens from the Accuracy-Based Survey from the College of American Pathologists, the newly developed assay agreed well with the CDC reference measurement procedure. In summary, immunoassay measurement of testosterone can be significantly inaccurate, especially at low concentrations. The newly developed LC-MS/MS assay provides accurate results across the entire measurable range.

Six Decades of Research on Human Fetal Gonadal Steroids

Human fetal gonads acquire endocrine steroidogenic capabilities early during their differentiation. Genetic studies show that this endocrine function plays a central role in the sexually dimorphic development of the external genitalia during fetal development. When this endocrine function is dysregulated, congenital malformations and pathologies are the result. In this review, we explain how the current knowledge of steroidogenesis in human fetal gonads has benefited from both the technological advances in steroid measurements and the assembly of detailed knowledge of steroidogenesis machinery and its expression in human fetal gonads. We summarise how the conversion of radiolabelled steroid precursors, antibody-based assays, mass spectrometry, ultrastructural studies, and the in situ labelling of proteins and mRNA have all provided complementary information. In this review, our discussion goes beyond the debate on recommendations concerning the best choice between the different available technologies, and their degrees of reproducibility and sensitivity. The available technologies and techniques can be used for different purposes and, as long as all quality controls are rigorously employed, the question is how to maximise the generation of robust, reproducible data on steroid hormones and their crucial roles in human fetal development and subsequent functions.

Fluorescence polarization immunoassay for rapid determination of dehydroepiandrosterone in human urine

In this paper, five fluorescein-labeled dehydroepiandrosterone (DHEA) derivatives (tracers) with different chain lengths between the fluorescein and hapten were synthesized and featured so as to establish a fluorescence polarization immunoassay (FPIA) for DHEA detection in human urine samples with previously prepared polyclonal antibody against DHEA. The outcomes of the structure of tracer on FPIA sensitivity were investigated. Under the optimal condition, the fluorescence polarization value (FP) decreases linearly in DHEA concentration, ranging from 1.6 to 243.3 ng mL^-1, with the limit of detection of 1.1 ng mL^-1 and IC₅₀ value of 25.1 ng mL^-1. Moreover, the developed FPIA was time-saving as it could complete the detection within 3 min. FPIA and commercial enzyme-linked immunosorbent assay kit were both applied to analyze the spiked human urine samples with DHEA. Excellent recoveries (92.1-108.0%) and satisfactory correlation coefficient (R² = 0.98) were acquired with the two methods, indicating that the developed FPIA was a fast and efficient screening immunoassay with accuracy and sensitivity for DHEA detection in human urine samples. Graphical abstract.

Quantitation of six steroid hormones by ultra-performance liquid chromatography-tandem mass spectrometry in plasma and prefrontal cortex samples from rats with chronic unpredictable mild stress-induced depression

Steroid hormones such as glucocorticoids and their metabolites are closely related to mental diseases and neuroendocrine diseases. Quantitative analysis of these substances will help in understanding their roles in related research fields. In this study, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to detect the concentration of corticosterone (CORT) and its metabolites, progesterone (PROG) and testosterone in rat plasma and prefrontal cortex (PFC), and was applied to investigate the changes in hormones in rats with depression induced by chronic unpredictable mild stress (CUMS). The method was shown to be linear in the quantitation range for all analytes. Intra- and inter-day accuracy and precision were between 80% and 120%. Furthermore, we found that the level of CORT in plasma and PFC increased, whereas that of 11-dehydrocorticosterone (11-DHCORT) as well as the ratio of 11-DHCORT and CORT declined in rats with CUMS-induced depression. The trends of these changes in central PFC and peripheral plasma were consistent. In conclusion, this study successfully established an UPLC-MS/MS method for simultaneous measurement of CORT and its metabolites, PROG and testosterone in rat plasma and PFC, and applied it to rats with depression. The method could be further applied to the research of depression and diseases related to these steroid hormones.

A Pt-Ir nanocube amplified lateral flow immunoassay for dehydroepiandrosterone

The traditional gold-nanoparticle-based lateral flow immunoassay (LFIA) cannot satisfy the requirements for the sensitive detection of dehydroepiandrosterone (DHEA) in human urine. To enhance the sensitivity of the LFIA, platinum-iridium nanocubes (Pt-Ir NCs) with high catalytic efficiency and stability were synthesized and labelled with polyclonal antibody (pAb) to form a pAb-Pt-Ir probe. For the detection of DHEA, a novel LFIA with Pt-Ir NCs as an optical label and an enhanced LFIA in which the peroxidase-like activity of the Pt-Ir NCs was triggered by the introduction of the chromogenic substrate 3-amino-9-ethyl-carbazole (AEC) were developed and compared with a LFIA with platinum nanocubes (PtNCs) as an optical label. The visual limit of detection was 0.5 ng mL-1 for Pt-Ir-LFIA and 0.05 ng mL-1 for AEC-enhanced Pt-Ir-LFIA, in comparison to 100 ng mL-1 for PtNCs-LFIA and 50 ng mL-1 for AEC-enhanced PtNCs-LFIA. The average recoveries from spiked urine samples ranged from 90.8% to 110.4%, with a coefficient of variation below 12.6%, suggesting the accuracy and reliability of our developed immunoassay. Achieving excellent sensitivity, specificity, and reproducibility, Pt-Ir-LFIA provided a promising platform for monitoring DHEA.

The Gut Microbiota Affects Corticosterone Production in the Murine Small Intestine

Glucocorticoids (GCs) are hormones that are released in response to stressors and exhibit many activities, including immunomodulatory and anti-inflammatory activities. They are primarily synthesized in the adrenal gland but are also produced in peripheral tissues via regeneration of adrenal 11-oxo metabolites or by de novo synthesis from cholesterol. The present study investigated the influence of the microbiota on de novo steroidogenesis and regeneration of corticosterone in the intestine of germ-free (GF) and specific pathogen-free mice challenged with a physical stressor (anti-CD3 antibody i.p. injection). In the small intestine, acute immune stress resulted in increased mRNA levels of the proinflammatory cytokines IL1β, IL6 and Tnfα and genes involved in de novo steroidogenesis (Stard3 and Cyp11a1), as well as in regeneration of active GCs from their 11-oxo metabolites (Hsd11b1). GF mice showed a generally reduced transcriptional response to immune stress, which was accompanied by decreased intestinal corticosterone production and reduced expression of the GC-sensitive marker Fkbp5. In contrast, the interaction between stress and the microbiota was not detected at the level of plasma corticosterone or the transcriptional response of adrenal steroidogenic enzymes. The results indicate a differential immune stress-induced intestinal response to proinflammatory stimuli and local corticosterone production driven by the gut microbiota.

Liquid chromatography-mass spectrometry applications for quantification of endogenous sex hormones

Liquid chromatography, coupled with tandem mass spectrometry, presents a powerful tool for the quantification of the sex steroid hormones 17-β estradiol, progesterone and testosterone from biological matrices. The importance of accurate quantification with these hormones, even at endogenous levels, has evolved with our understanding of the role these regulators play in human development, fertility and disease risk and manifestation. Routine monitoring of these analytes can be accomplished by immunoassay techniques, which face limitations on specificity and sensitivity, or using gas chromatography-mass spectrometry. LC-MS/MS is growing in capability and acceptance for clinically relevant quantification of sex steroid hormones in biological matrices and is able to overcome many of the limitations of immunoassays. Analyte specificity has improved through the use of novel derivatizing agents, and sensitivity has been refined through the use of high-resolution chromatography and mass spectrometric technology. This review highlights these innovations, among others, in LC-MS/MS steroid hormone analysis captured in the literature over the last decade.

Changes in Adrenal Androgens and Steroidogenic Enzyme Activities From Ages 2, 4, to 6 Years: A Prospective Cohort Study

CONTEXT

The levels of adrenal androgens are increased through the action of steroidogenic enzymes with morphological changes in the adrenal zona reticularis.

OBJECTIVE

We investigated longitudinal changes in androgen levels and steroidogenic enzyme activities during early childhood.

DESIGN AND PARTICIPANTS

From a prospective children's cohort, the Environment and Development of Children cohort, 114 boys and 86 girls with available blood samples from ages 2, 4, and 6 years were included.

OUTCOME MEASUREMENTS

Serum concentrations of adrenal androgens using liquid chromatography-tandem mass spectrometry and steroidogenic enzyme activity calculated by the precursor/product ratio.

RESULTS

During ages 2 to 4 years, 17,20-lyase and dehydroepiandrosterone (DHEA) sulfotransferase activities increased (P < 0.01 for both in boys). During ages 4 to 6 years, 17,20-lyase activity persistently increased, but 3β-hydroxysteroid dehydrogenase (HSD) and 17β-HSD activities decreased (P < 0.01 for all). Serum DHEA sulfate (DHEA-S) levels persistently increased from 2, 4, to 6 years, and DHEA, 17-hydroxyprogesterone, and androstenedione levels increased during ages 4 to 6 years (P < 0.01 for all). Serum DHEA-S levels during early childhood were associated with body mass index z-scores (P = 0.001 in only boys).

CONCLUSION

This study supports in vivo human evidence of increased 17,20-lyase and DHEA sulfotransferase activities and decreased 3β-HSD activity during early childhood.