Total testosterone quantitative measurement in serum by LC-MS/MS

Electrochemical aptasensor for determination of testosterone using an aptamer-nanogold-metal-organic framework-ionic liquid modified carbon paste electrode

The present study is based on the design and construction of a selective label-free electrochemical aptasensor for testosterone (TST) detection in real samples. A carbon paste electrode modified with gold nanoparticles and metal-organic framework-ionic liquid (AuNPs/Fe3O4-NH2@Cu-ILCPE) was used to covalently immobilize the TST aptamer (TST-apt). The AuNPs/Fe3O4-NH2@Cu-ILCPE represents a distinguished ability for enhancement of electrochemical peak current, which may emerge from the aptamer on the electrode surface. Initially, the dependency of signals to variables like the aptamer concentration, aptamer immobilization time, AuNPs electrodeposion time, and aptamer reaction time was investigated and optimized. Under the optimized conditions, the proposed aptasensor has two linear ranges over 1.0-50.0 nM and 50.1-1000.0 nM with a limit of detection of 0.31 nM, and a limit of quantification of 0.99 nM. The aptasensor was also applicable to detecting TST in urine samples with satisfactory recoveries of 97.2-103.8 %.

Detection of testosterone based on the interaction between variable regions of antibody heavy chain and light chain

Introduction

Testosterone is a steroid hormone, which plays a pivotal role in regulating metabolism and protein synthesis in the body. The detection of testosterone is of paramount importance for diagnostic purposes in clinical settings, as well as for monitoring athletes' physiological parameters and ensuring the integrity of sports competitions.

Methods

Herein, we present a phage display-derived biosensing platform through genetic engineering of the TS77 antibody variable domains. The variable region genes of the heavy and light chains from TS77 antibody were cloned into the pDong1 plasmid and displayed on the phage surfaces through phage display technology. Subsequently, a novel non-competitive open-sandwich ELISA (OS-ELISA) was developed for testosterone detection, leveraging the antigen-induced interaction changes in antibody variable regions.

Results

OS-ELISA based on anti L-chain antibody achieved a limit of detection (LOD) of 2.71 nM and a half-maximal effective concentration (EC50) of 0.22 μM for testosterone detection. Furthermore, the enhanced OS-ELISA platform incorporating purified maltose binding protein fused with VL (MBP-VL) and VH phage demonstrated a LOD of 1.07 pM and a wide working range from 1 pM to 10 mM.

Discussion

The OS-ELISA developed in this study exhibits high sensitivity and a broad dynamic range for testosterone quantification, showing significant potential for clinical diagnostics and athlete monitoring applications.

Rapid Liquid Chromatography-Tandem Mass Spectrometry Method for Determination of Total and Free Testosterone in Human Serum and Its Application to Monitoring Biomarker Response of Elite Athletes

Total testosterone (TT) and free testosterone (FT) are important biochemical markers for anabolism of the human body, and can also serve as early screening indicators for overtraining syndrome (OTS). Presently, there is no fast and reliable serum TT and FT determination method in the field of sport science that can meet the requirements of sports research. Thus, a rapid and accurate determination method for serum TT and FT to fill the gap is needed urgently in sports training. Herein, a simple and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of TT and FT in serum was developed and fully validated, followed by the application of professional athletes in training monitoring. Efficient pretreatments based on only one-step liquid-liquid extraction (LLE) for TT and one-step LLE after a 20 min ultrafiltration for FT were adopted in this study, and the isotope internal standard of testosterone-13C3 was used to ensure the reliability of the whole procedure. A linear range of four orders of magnitude with 0.02-100 ng/mL can meet the concentration range requirement between a higher limit for male TT and a lower limit for female FT. The accuracy, precision, stability, and matrix effect were all within the limits of the guidelines. The serum TT and FT levels of 200 professional athletes (98 male athletes and 102 female athletes) were investigated by this method. Serum TT, FT, and FT/TT levels of professional athletes were significantly higher than the general population, and serum TT levels were significantly higher by LC-MS/MS than by a chemiluminescence immunoassay. In conclusion, the LC-MS/MS method for TT and FT measurement developed in this study is time-saving and easy to operate, which can be used as a reliable method for the determination of serum TT and FT in sports training, offering valuable information for monitoring anabolism of athletes and screening OTS in the early stage.

Glucocorticoid modulates oxidative and thermogenic function of rat brown adipose tissue and human brown adipocytes

Chronic and excessive glucocorticoid (GC) exposure can cause Cushing's syndrome, resulting in fat accumulation in selected body areas. Particularly in the brown adipose tissue (BAT), GC acts negatively, resulting in whitening of the tissue. We hypothesized that dysregulation of microRNAs by GC could be an additional mechanism to explain its negative actions in BAT. Male Wistar rats were divided into two groups: (1) Control sham and (2) GC group that was administered dexamethasone 6.25 mg/200 μL via osmotic pump implantation over 28 days. After this period, the animals were euthanized and BAT tissue was properly stored. Human fat cells treated with dexamethasone were used to translate the experimental results found in animals to human biology. GC-treated rat BAT presented with large lipid droplets, severely impaired thermogenic activation, and reduced glucose uptake measured by 18F-FDG PET/CT. GC exposure induced a reduction in the mitochondrial OXPHOS system and oxygen consumption. MicroRNA profiling of BAT revealed five top-regulated microRNAs and among them miR-21-5p was the most significantly upregulated in GC-treated rats compared to the control group. Although upregulation of miR-21-5p in the tissue, differentiated primary brown adipocytes from GC-treated rats had decreased miR-21-5p levels compared to the control group. To translate these results to the clinic, human brown adipocytes were treated with dexamethasone and miR-21-5p inhibitor. In human brown cells, inhibition of miR-21-5p increased brown adipocyte differentiation and prevented GC-induced glucose uptake, resulting in a lower glycolysis rate. In conclusion, high-dose GC therapy significantly impacts brown adipose tissue function, with a notable association between glucose uptake and miR-21-5p.

Distorted correlations among censored data: causes, effects, and correction

Data censoring occurs when researchers do not know precise values of data points (e.g., age is 55+ or concentration ≤ .001). Censoring is frequent within psychology but typically unrecognized outside of longitudinal studies. We describe five circumstances when censoring may occur, demonstrate censoring distorts correlations, and discuss how censoring can create spurious factors. Next, we explain how to use R package lava to calculate maximum likelihood estimates (Holst and Budtz-Jørgensen Computational Statistics, 28(4), 1385-1452, 2013) of correlations between uncensored variables based upon censored variables. Previous research demonstrated these estimates were more accurate than Muthén's (1984) estimate for one particular model, but no research has systematically examined their accuracy. We therefore conducted a simulation study exploring the effects of the correlation, sample size, and censoring on point and interval estimates of correlations. Based upon 80 cells in which low values of normally distributed variables were censored, we recommend the constrained regression model with Wald confidence intervals. These methods were precise and unbiased unless both variables had 70% censoring and the correlation was large and negative (e.g., -.9), in which case estimates were closer to -1 than they should be. Opposite results would occur if low values of one variable and high values of the other were censored: Estimates would be precise and unbiased unless censoring was extreme and correlations were large and positive. To estimate large correlations accurately, we recommend researchers reduce censoring by using longer longitudinal studies, using scales with more response options, and matching measures to populations to reduce floor and ceiling effects.

The Edge Effect in High-Throughput Proteomics: A Cautionary Tale

In order for mass spectrometry to continue to grow as a platform for high-throughput clinical and translational research, careful consideration must be given to quality control by ensuring that the assay performs reproducibly and accurately and precisely. In particular, the throughput required for large cohort clinical validation in biomarker discovery and diagnostic screening has driven the growth of multiplexed targeted liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) assays paired with sample preparation and analysis in multiwell plates. However, large scale MS-based proteomics studies are often plagued by batch effects: sources of technical variation in the data, which can arise from a diverse array of sources such as sample preparation batches, different reagent lots, or indeed MS signal drift. These batch effects can confound the detection of true signal differences, resulting in incorrect conclusions being drawn about significant biological effects or lack thereof. Here, we present an intraplate batch effect termed the edge effect arising from temperature gradients in multiwell plates, commonly reported in preclinical cell culture studies but not yet reported in a clinical proteomics setting. We present methods herein to ameliorate the phenomenon including proper assessment of heating techniques for multiwell plates and incorporation of surrogate standards, which can normalize for intraplate variation.

Electrochemically Pretreated Sensor Based on Screen-Printed Carbon Modified with Pb Nanoparticles for Determination of Testosterone

Testosterone (TST), despite its good properties, may be harmful to the human organism and the environment. Therefore, monitoring biological fluids and environmental samples is important. An electrochemically pretreated screen-printed carbon sensor modified with Pb nanoparticles (pSPCE/PbNPs) was successfully prepared and used for the determination of TST. The surface morphology and electrochemical properties of unmodified and modified sensors were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning and transmission electron microscopy (SEM and TEM), and energy-dispersive X-ray spectroscopy (EDS). Selective determinations of TST at the pSPCE/PbNPs were carried out by differential pulse adsorptive stripping voltammetry (DPAdSV, E_{Pb dep.and TST acc.} of −1.1 V, t _{Pb dep.and TST acc.} of 120 s, ΔE_A of 50 mV, ν of 175 mV s⁻¹, and t_m of 5 ms) in a solution containing 0.075 mol L⁻¹ acetate buffer of pH = 4.6 ± 0.1, and 7.5 × 10⁻⁵ mol L⁻¹ Pb(NO₃)₂. The analytical signal obtained at the potential around −1.42 V (vs. silver pseudo-reference electrode) is related to the reduction process of TST adsorbed onto the electrode surface. The use of pSPCE/PbNPs allows obtaining a very low limit of TST detection (2.2 × 10⁻¹² mol L⁻¹) and wide linear ranges of the calibration graph (1.0 × 10⁻¹¹–1.0 × 10⁻¹⁰, 1.0 × 10⁻¹⁰–2.0 × 10⁻⁹, and 2.0 × 10⁻⁹–2.0 × 10⁻⁸ mol L⁻¹). The pSPCE/PbNPs were successfully applied for the determination of TST in reference material of human urine and wastewater purified in a sewage treatment plant without preliminary preparation.

Th17 cells-linked mechanisms mediate vascular dysfunction induced by testosterone in a mouse model of gender-affirming hormone therapy

Clinical data point to adverse cardiovascular events elicited by testosterone replacement therapy. Testosterone is the main hormone used in gender-affirming hormone therapy (GAHT) by transmasculine people. However, the cardiovascular impact of testosterone in experimental models of GAHT remains unknown. Sex hormones modulate T cells activation, and immune mechanisms contribute to cardiovascular risk. The present study evaluated whether testosterone negatively impacts female cardiovascular function by enhancing Th17 cells-linked effector mechanisms. Female (8 weeks-old) C57BL/6J mice received testosterone (48 mg.Kg^-1.week^-1) for 8 weeks. Male mice were used for phenotypical comparisons. The hormone-treatment in female mice increased circulating testosterone to levels observed in male mice. Testosterone increased lean body mass and body mass index, and decreased perigonadal fat mass, mimicking clinical findings. After 8 weeks, testosterone decreased endothelium-dependent vasodilation and increased circulating Th17 cells. After 24 weeks, testosterone increased blood pressure in female mice. Ovariectomy did not intensify phenotypical or cardiovascular effects by testosterone. Female mice lacking T and B cells [Rag1 knockout (^-/-)], as well as female mice lacking IL-17 receptor (IL-17Ra^-/-), did not exhibit vascular dysfunction induced by testosterone. Testosterone impaired endothelium-dependent vasodilation in female mice lacking γδ T cells, similarly to the observed in wild type female mice. Adoptive transfer of CD4⁺ T cells restored testosterone-induced vascular dysfunction in Rag1^-/- female mice. Together, these data suggest that CD4⁺ T cells, most likely Th17 cells, are central to vascular dysfunction induced by testosterone in female mice, indicating that changes in immune cells balance are important in the GAHT in transmasculine people.

Determination of testosterone in serum by magnetic molecularly imprinted polymer-coupled nano-ESI-MS

Monitoring clinical biomarkers, such as testosterone in serum, is important for disease assessment. Due to the very low concentration of testosterone in serum, we have developed a new strategy for its enrichment in serum samples by magnetic molecularly imprinted polymers (MMIPs) technology and detection by nano-electrospray ionization mass spectrometry (Nano-ESI-MS). Testosterone was selectively extracted and enriched by the imprinted polymers on the surface of magnetic particles and the complex matrix was eliminated from the serum. The linear calibration curve was in the range of 0.1-10 μg/L and the limit of detection was 11.4 ng/L. The recovery and repeatability of the spiked serum were satisfactory. These results demonstrate that the proposed method is a promising approach for quantitative analysis of testosterone in serum.

A tandem liquid chromatography and tandem mass spectrometry (LC/LC-MS/MS) technique to separate and quantify steroid isomers 11β-methyl-19-nortestosterone and testosterone

Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) has become a mainstay analytical technique in pharmaceutical research and development and clinical diagnosis due to several advantages including excellent selectivity, specificity, and high sensitivity. LC-MS/MS has become the method of choice for steroids analysis due to its fast analytical time and improved specificity yet has a challenge in the separation and measurement of isomers with the same product ions. Here we describe a high-sensitivity LC/LC-MS/MS method that combines chiral chromatography and reverse-phase chromatography (LC/LC) along with MS/MS to rapidly separate and quantify steroid isomers of 11ß-methyl-19-nortestosterone (11ß-MNT) and endogenous testosterone in serum.

Rapid quantitative analysis of hormones in serum by multilayer paper spray MS: Free MS from HPLC

Developing rapid and reliable method for simultaneous hormones quantitation is of great significant because of important roles of hormones in metabolism. However, current methods are faced with problems of low throughput or complicated operation procedure to remove matrices from serum samples in routine clinical diagnosis. In the present work, a multilayer PS-MS method was developed for rapid and simple detection of hormones. In the strategy, multilayer filter paper acted as the Liquid Chromatography in LC-MS/MS for separation of hormones and biological matrices. Qualitative and quantitative analysis of three hormones, testosterone (T), androsterone (ADT) and androstenedione (4-AD) were realized through MS/MS spectra. The method exhibited linearity in the range of 0.02-2 μg/L and the results of recovery and repeatability were satisfactory for standard samples and spiked serum. The time-cost of a whole detection process was less than 3 min. The established multilayer PS-MS realized rapid, simple and reliable quantitative analysis of various hormones and provided broad prospect for clinical analysis of small molecules in different biological samples. Moreover, it provides a novel MS approach with high through-put and free HPLC, meeting the requirements of point-of-care testing (POCT).

A developed HPLC-MS/MS method to quantitate 5 steriod hormones in clinical human serum by using PBS as the surrogate matrix

Steroid hormones play an essential role in regulating physiological and reproductive development throughout the lifetime of an individual. One of the difficulties in determining endogenous substances is the lack of a blank matrix. Especially when the level of analytes is lower than the level in the so-called blank matrix. In the present study, an optimized HPLC-MS/MS method was developed and validated to quantify androstenedione (ASD), testosterone (Ts), dehydroepiandrosterone (DHEA), 5α-dihydrotestosterone (DHT), and progesterone (P) in serum samples from healthy people using PBS (pH = 7.4) as the blank surrogate matrix. Simultaneously, the method investigated the characteristics of NaCl, bull serum albumin, pure water as surrogate matrices for the analysis of steroid hormones. The data showed that the matrix effects of ASD, Ts, DHEA, DHT, and P in the same groups were not significantly different between PBS and twice charcoal-stripped serum (CS₂S) as a blank surrogate matrix. Furthermore, the LLOQ using PBS as the blank matrix was up to 0.005 ng/mL for ASD, Ts, and P and 0.05 ng/mL for DHEA and DHT. The reference ranges of concentration (C_PBS) of 5 steroid hormones were provided. Compared to the concentration with CS₂S (C_CSS) as the blank surrogate matrix, the relative biases (RBs) of Ts, DHT, P, and DHEA were finally stabilized at approximately -0.7%, -15%, -1.2%, and 9.2%, respectively. The results suggest that, in the cases of special required, the developed HPLC-MS/MS method can be used to determine the absolute concentration of 5 hormones in biological samples with PBS as the blank surrogate matrix.

Comparison of American Urological Association and Endocrine Society guidelines on testosterone replacement

Low testosterone affects an increasing number of patients each year resulting in a steady increase in prescriptions for testosterone replacement therapy (TRT). In 2018, the American Urological Association (AUA) and the Endocrine Society (ES) published their guidelines for treating patients with low testosterone. While the two guidelines are similar, significant differences exist. In this review, we compare and analyze the AUA and ES guidelines in terms of diagnosis and definition, workup, monitoring of side effects, treatment outcomes for TRT, and how these guidelines are applied in our practice.

In Pursuit of Pleasure: A Biopsychosocial Perspective on Sexual Pleasure and Gender

Objective: Various sources of evidence suggest that men and women differ in their experience of sexual pleasure. Such gender differences have been attributed to men's higher innate sex drive, supported by evolutionary psychology perspectives and gender differences in reproductive strategies. Method: This paper presents biopsychosocial evidence for gender similarities in the capacity to experience pleasure, and for substantial gender differences in opportunities for sexual pleasure. Results: We conclude that sexual activity, in most cultures, is less pleasurable and associated with greater cost for heterosexual women than for heterosexual men, even though they do not differ in the capacity for sexual pleasure. Conclusion: Since gender differences in experienced sexual pleasure are not a biological given, a more critical discourse of sexual pleasure might create awareness of current inequalities, help lift restrictions for women's opportunities for pleasure, and could reduce gender differences in the cost of sex. That would truly serve sexual justice around the globe.

Sample Preparation and Analytical Methods for Steroid Hormones in Environmental and Food Samples: An Update Since 2012

Steroid hormones (SHs) have been widely used over the past few decades as both human and veterinary drugs to prevent or treat infectious diseases and anti-inflammatory benefits in clinical. Unfortunately, their residues in foodstuffs and environmental samples can produce adverse effects on human and animal life such as disrupting the endocrine system. For these reasons, sensitive, simple and efficient methods have been developed for the determination of these compounds in various matrices. This critical review summarized the articles published in the period from 2012 to 2019 and can be used to help researchers to understand development of the sample pretreatment protocols and analytical methods used to detect SHs. The developed extraction and purification techniques used for steroids in different samples, such as cloud point extraction, solid phase extraction based on different novel materials, microextraction methods, QuEChERS and other methods are summarized and discussed. Analytical methods used to quantify these compounds, such as different chromatography methods, electrochemical methods, as well as other methods, are illustrated and compared. We focused on the latest advances in SHs pretreatment, and the application of new technologies in SHs analysis.

Aging and sex hormones in males

Over the past two decades several large cohort studies have been performed to disclose the changes of sex hormone in elderly and their clinical significance. Beyond the decline of total testosterone, aging is accompanied by a sex hormone binding globulin (SHBG) increase, a steeper free testosterone decline, while gonadotropins may be increased or inappropriately normal, with important contribution of comorbidities (e.g., obesity) to these changes. Actually, it has become firm the concept that the biochemical finding of testosterone deficiency alone is not sufficient for diagnosing hypogonadism in older men. The definition of late-onset hypogonadism (LOH) includes low serum testosterone levels coupled with signs and symptoms related to hypogonadism. Indeed, the combination of multiple factors all contributing to the testosterone decline, with other concurrent comorbidities further overlapping, makes the clinical correlates of LOH highly heterogeneous. For all these reasons both the diagnosis and the therapeutic management of LOH, especially the decision about starting testosterone replacement treatment, remain challenging.

From a single steroid to the steroidome: Trends and analytical challenges

For several decades now, the analysis of steroids has been a key tool in the diagnosis and monitoring of numerous endocrine pathologies. Thus, the available methods used to analyze steroids in biological samples have dramatically evolved over time following the rapid pace of technology and scientific knowledge. This review aims to synthetize the advances in steroids' analysis, from classical approaches considering only a few steroids or a limited number of steroid ratios, up to the new steroid profiling strategies (steroidomics) monitoring large sets of steroids in biological matrices. In this context, the use of liquid chromatography coupled to mass spectrometry has emerged as the technique of choice for the simultaneous determination of a high number of steroids, including phase II metabolites, due to its sensitivity and robustness. However, the large dynamic range to be covered, the low natural abundance of some key steroids, the selectivity of the analytical methods, the extraction protocols, and the steroid ionization remain some of the current challenges in steroid analysis. This review provides an overview of the different analytical workflows available depending on the number of steroids under study. Special emphasis is given to sample treatment, acquisition strategy, data processing, steroid identification and quantification using LC-MS approaches. This work also outlines how the availability of steroid standards, the need for complementary analytical strategies and the improvement of calibration approaches are crucial for achieving complete steroidome quantification.

Derivatization with 2-hydrazino-1-methylpyridine enhances sensitivity of analysis of 5α-dihydrotestosterone in human plasma by liquid chromatography tandem mass spectrometry

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Quantitative analysis of low abundance androgens in human plasma.

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Quantitation of androgens over physiological range in men and post-menopausal women.

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Use of hydrazine derivatives improves analytical sensitivity.

Liquid Chromatography tandem mass spectrometry (LC-MS/MS) is the gold-standard approach for androgen analysis in biological fluids, superseding immunoassays in selectivity, particularly at low concentrations. While LC-MS/MS is established for analysis of testosterone and androstenedione, 5α-dihydrotestosterone (DHT) presents greater analytical challenges. DHT circulates at low nanomolar concentrations in men and lower in women, ionizing inefficiently and suffering from isobaric interference from other androgens. Even using current LC-MS/MS technology, large plasma volumes (>0.5 mL) are required for detection, undesirable clinically and unsuitable for animals. This study investigated derivatization approaches using hydrazine-based reagents to enhance ionization efficiency and sensitivity of analysis of DHT by LC-MS/MS. Derivatization of DHT using 2-hydrazino-1-methylpyridine (HMP) and 2-hydrazino-4-(trifluoromethyl)-pyrimidine (HTP) were compared. A method was validated using an UHPLC interfaced by electrospray with a triple quadruple mass spectrometer , analyzing human plasma (male and post-menopausal women) following solid-phase extraction. HMP derivatives were selected for validation affording greater sensitivity than those formed with HTP. HMP derivatives were detected by selected reaction monitoring (DHT-HMP m/z 396→108; testosterone-HMP m/z 394→108; androstenedione-HMP m/z 392→108). Chromatographic separation of androgen derivatives was optimized, carefully separating isobaric interferents and acceptable outputs for precision and trueness achieved following injection of 0.4 pg on column (approximately 34 pmol/L). HMP derivatives of all androgens tested could be detected in low plasma volumes: male (100 µL) and post-menopausal female (200 µL), and derivatives were stable over 30 days at -20°C. In conclusion, HMP derivatization, in conjunction with LC-MS/MS, is suitable for quantitative analysis of DHT, testosterone and androstenedione in low plasma volumes, offering advantages in sensitivity over current methodologies.

Determination of testosterone/epitestosterone concentration ratio in human urine by capillary electrophoresis

A novel method for determining the testosterone/epitestosterone concentration ratio in human urine was established by capillary electrophoresis with diode-array detector. The urine samples were firstly purified by the solid extraction. The optimal experimental conditions were: running buffer pH = 4.74, 15.0 mmol L^-1 HAc-NaAc, separation voltage 25 kV, temperature 25 °C, sample injection pressure 3.43 × 10³ Pa, and duration 10 s. The testosterone and epitestosterone linear range were determined as 8.0-960.0 ng mL^-1, respectively. The testosterone and epitestosterone detection limits were determined as 4.6 and 4.5 ng mL^-1, respectively. The relative standard deviation was less than 0.36%.

Resetting the Bar of Castration Resistance - Understanding Androgen Dynamics in Therapy Resistance and Treatment Choice in Prostate Cancer

This review discusses impact of advancements in biologic understanding of prostate cancer (PCa) on definition and diagnosis of castration-resistant PCa (CRPC), predictive factors for progression to CRPC and treatment strategies. More sensitive assays confirm that bilateral orchiectomy reduces serum testosterone (T) closer to < 20 ng/dL than < 50 ng/dL, and evidence suggests that achieving T < 20 ng/dL improves outcomes and delays CRPC emergence. Regular T assessments will evaluate whether T is adequately suppressed in the setting of potential progression to CRPC, given that late dosing may result in T escape. More advanced imaging modalities and biomarker assays allow earlier detection of disease progression. Predictive factors for progression to CRPC include Gleason grade, extent of metastatic spread, germline hereditary factors such as gene mutations affecting androgen receptor amplification or DNA repair deficiency mutations, prostate-specific antigen kinetics, and biomarker analyses. Treatment options for CRPC have expanded beyond androgen deprivation therapy to include therapies that suppress T or inhibit its activity through varying mechanisms. Future directions include therapies with novel biological targets, drug combinations and personalized treatments. Advanced PCa management aims to delay progression to CRPC and prolong survival. With redefinition of castration and advancements in understanding of the biology of disease progression, diagnosis and treatment strategies should be re-evaluated. Definition of CRPC could be updated to reflect the T < 20 ng/dL requirement as this is a 'true' castrate level and may improve outcomes. It is important that androgen deprivation therapy as foundational therapy is continued even as new CRPC therapies are introduced.

The predictive value of total testosterone alone for clinical hyperandrogenism in polycystic ovary syndrome

RESEARCH QUESTION

Is the sole measurement of total testosterone sufficient to assess the presence of hyperandrogenism in women with polycystic ovary syndrome (PCOS)?

DESIGN

Serum samples from 294 patients with PCOS who met the Rotterdam criteria were used for the analysis of total testosterone by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) and chemiluminescent immunoassay (CLIA). The free androgen index (FAI) was calculated as total testosterone (TT)/sex hormone-binding globulin (SHBG) × 100%, and the presence/degree of hirsutism were assessed using the modified and simplified Ferriman-Gallwey (mFG and sFG, respectively) scoring systems.

RESULTS

The hirsute subjects presented higher LC-MS/MS-based total testosterone and FAI values than the non-hirsute subjects (all P < 0.001), including those defined based on mFG ≥5 or sFG ≥3. Total testosterone and FAI were both positively correlated with the mFG (rank correlation coefficient [RCC] 0.598 and 0.443, P < 0.001) or sFG (RCC 0.747 and 0.568, P < 0.001) score, and a receiver operating characteristic curve analysis indicated that both parameters could significantly predict the presence of hirsutism determined by the mFG (area under the curve [AUC] 0.797 and 0.725, P < 0.001) or sFG (AUC 0.894 and 0.817, P < 0.001) score. However, similar results were not obtained with the CLIA platform.

CONCLUSIONS

In this East Asian population, total testosterone was found to be a strong predictor of the presence and degree of hyperandrogenism (i.e. assessed by the presence and degree of hirsutism), but this finding was obtained only if the total testosterone level was measured by LC-MS/MS and not by CLIA. These findings might have important implications for global epidemiologic, phenotypic and clinical studies of PCOS.

A New LC-MS/MS Method for Simultaneous and Quantitative Detection of Bisphenol-A and Steroids in Target Tissues: A Power Tool to Characterize the Interference of Bisphenol-A Exposure on Steroid Levels

Bisphenol A (BPA), an endocrine disruptor, may affect in situ steroidogenesis and alter steroids levels. The present work proposes a liquid chromatography tandem mass spectrometry method to simultaneously quantify BPA, 17β-Estradiol and testosterone in two target tissues: testis and visceral fat mass. Analytes were isolated and lipophilic impurities removed by two serial steps: liquid-liquid and solid phase extraction. All compounds were separated in a single gradient run by Kinetex F5 column and detected via multiple reaction monitoring using a triple quadrupole with a TurboIon electrospray source in both negative and positive modes. The method is selective and very sensitive. In the investigated concentration range, the linearity of the detector response is verified in both tissues. The use of specific SPE cartridges for affinity chromatography purification allows obtaining high percentages of process efficiency (68.0-83.3% for testicular tissue; 63.7-70.7% for visceral fat mass). Good repeatability and reproducibility was observed. The validated method can be efficiently applied for direct biological monitoring in testis and visceral fat mass from mice exposed to BPA. The quantification of compounds in a single assay could be achieved without a loss of sensitivity.

Molecularly Imprinted Polymer-Based Microfluidic Systems for Point-of-Care Applications

Fast progress has been witnessed in the field of microfluidic systems and allowed outstanding approaches to portable, disposable, low-cost, and easy-to-operate platforms especially for monitoring health status and point-of-care applications. For this purpose, molecularly imprinted polymer (MIP)-based microfluidics systems can be synthesized using desired templates to create specific and selective cavities for interaction. This technique guarantees a wide range of versatility to imprint diverse sets of biomolecules with different structures, sizes, and physical and chemical features. Owing to their physical and chemical robustness, cost-friendliness, high stability, and reusability, MIP-based microfluidics systems have become very attractive modalities. This review is structured according to the principles of MIPs and microfluidic systems, the integration of MIPs with microfluidic systems, the latest strategies and uses for point-of-care applications and, finally, conclusions and future perspectives.

A robust LC-MS/MS assay with online cleanup for measurement of serum testosterone

Accurate measurement of low levels of testosterone is critical for diagnosis and treatment of androgen disorders. The very low concentrations of testosterone in children, females, and males with androgen suppression therapies necessitate the use of mass spectrometry-based methods. We aimed to develop a liquid chromatography with tandem mass spectrometry method with simplified sample preparation and online solid-phase extraction cleanup to achieve enhanced precision, accuracy, robustness, and cost-effectiveness. The assay was linear from 10 to 20 000 pg/mL with an analytical recovery of 93-104%. The total coefficient of variation was 2.5, 1.9, and 1.7% at concentration levels of 348, 5432, and 10 848 pg/mL, respectively. No significant carryover was observed from samples with concentrations up to 20 000 pg/mL. No significant interference was observed from androstenedione, dehydroepiandrosterone, epi-testosterone, and estriol. Comparison with CDC Hormone Standardization program (HoSt) reference samples with defined values (n = 40) showed a Deming regression slope of 0.963, intercept of 28.06 pg/mL, standard error of estimate was 66.9, a correlation coefficient of 0.9996, and a mean bias of -0.6%. The method met the accuracy criteria by the CDC HoSt program. In addition, we achieved >12 000 injections on a single analytical column without significant performance deterioration due to the specific online solid-phase extraction settings.

Sex Hormones and Anticancer Immunity

The impact of sex hormones on anticancer immunity deserves attention due to the importance of the immune system in cancer therapy and the recognition of sex differences in immunity. Cancer is ultimately the result of failed immune surveillance, and the diverging effects of male and female sex hormones on anticancer immunity could contribute to the higher cancer incidence and poorer outcome in men. Estrogens and androgens affect the number and function of immune cells, an effect that depends on cell type, tumor microenvironment, and the age and reproductive status of the individual. Despite the recent progress in immuno-oncology, our current understanding of the interplay between sex hormones and anticancer immune responses is in its infancy. In this review, we will focus on the impact of sex hormones on anticancer immunity and immunotherapy. We will discuss the potential role of the changing hormone levels in anticancer immunity during aging and in the context of menopausal hormone therapies and oral contraception. We will review emerging data on sex differences in PD-L1 expression and potential biomarkers predictive for the efficacy of immune checkpoint inhibitors such as the microbiome and consider ongoing clinical trials evaluating the potential impact of hormone deprivation therapies to increase response to immune checkpoint inhibitors in breast and prostate cancer. Finally, we will point to areas of future research.

Evaluation of a one-step sample preparation protocol for analysis of total serum testosterone by LC-MS/MS

In this study, a one-step method for liquid-liquid extraction has been compared against a two-step procedure for testosterone assays in terms of accuracy, specificity, recovery, lipid removal and baseline noise, using QCs and unknown samples. The difference in accuracy was less than 5% for adult sera, while it was less than 10% for prepubescent sera. To compare specificity, the ion ratio transition of 289 → 97 to 289 → 109 was monitored for all QCs and unknown samples; no interference in the testosterone peak was observed for any tested sample prepared by either the one-step or two-step procedure. The baseline comparison of LC-MS/MS chromatograms of samples indicated that samples prepared by the one-step procedure were of the same quality as those prepared by the two-step procedure; however, recovery in unaltered serum using the one-step procedure was approximately 15% greater across the low to high concentration range. Furthermore, recovery using the one-step procedure was more consistent between stripped and unstripped serum. Lipids were removed efficiently in the two-step procedure as verified by monitoring the typical phospholipid MRM transition of m/z 496 → 184. For every sample processed by the one-step procedure, a one-minute online column wash with 95% methanol was able to remove 95% of the bound lipids, thereby providing a column life-time approximately equivalent to that for the two-step procedure. The presented data indicate that the one-step procedure could replace the two-step procedure while maintaining accuracy, saving time, increasing recovery, and minimizing the potential for errors with the fewer steps required.

Micro-patterned molecularly imprinted polymer structures on functionalized diamond-coated substrates for testosterone detection

Molecularly imprinted polymers (MIPs) can selectively bind target molecules and can therefore be advantageously used as a low-cost and robust alternative to replace fragile and expensive natural receptors. Yet, one major challenge in using MIPs for sensor development is the lack of simple and cost-effective techniques that allow firm fixation as well as controllable and consistent receptor material distribution on the sensor substrate. In this work, a convenient method is presented wherein microfluidic systems in conjunction with in situ photo-polymerization on functionalized diamond substrates are used. This novel strategy is simple, efficient, low-cost and less time consuming. Moreover, the approach ensures a tunable and consistent MIP material amount and distribution between different sensor substrates and thus a controllable active sensing surface. The obtained patterned MIP structures are successfully tested as a selective sensor platform to detect physiological concentrations of the hormone disruptor testosterone in buffer, urine and saliva using electrochemical impedance spectroscopy. The highest added testosterone concentration (500 nM) in buffer resulted in an impedance signal of 10.03 ± 0.19% and the lowest concentration (0.5 nM) led to a measurable signal of 1.8 ± 0.15% for the MIPs. With a detection limit of 0.5 nM, the MIP signals exhibited good linearity between a 0.5 nM and 20 nM concentration range. Apart from the excellent and selective recognition offered by these MIP structures, they are also stable during and after the dynamic sensor measurements. Additionally, the MIPs can be easily regenerated by a simple washing procedure and are successfully tested for their reusability.

Simultaneous measurement of total estradiol and testosterone in human serum by isotope dilution liquid chromatography tandem mass spectrometry

Reliable measurement of total testosterone and estradiol is critical for their use as biomarkers of hormone-related disorders in patient care and translational research. We developed and validated a mass spectrometry method to simultaneously quantify these analytes in human serum without chemical derivatization. Serum is equilibrated with isotopic internal standards and treated with acidic buffer to release hormones from their binding proteins. Lipids are isolated and polar impurities are removed by two serial liquid-liquid extraction steps. Total testosterone and estradiol are measured using liquid chromatography tandem mass spectrometry (LC-MS/MS) in combination of positive and negative electrospray ionization modes. The method shows broad analytical measurement range for both testosterone 0.03-48.5 nM (0.75-1400 ng/dL) and estradiol 11.0-5138 pM (2.99-1400 pg/mL) and excellent agreement with certified reference materials (mean bias less than 2.1% to SRM 971, BCR 576, 577, and 578) and a high order reference method (mean bias 1.25% for testosterone and -0.84% for estradiol). The high accuracy of the method was monitored and certified by CDC Hormone Standardization (HoSt) Program for 2 years with mean bias -0.7% (95% CI -1.6% to 0.2%) for testosterone and 0.1% (95% CI -2.2% to 2.3%) for estradiol. The method precision over a 2-year period for quality control pools at low, medium, and high concentrations was 2.7-2.9% for testosterone and 3.3-5.3% for estradiol. With the consistently excellent accuracy and precision, this method is readily applicable for high-throughput clinical and epidemiological studies.

Systematic review of serum steroid reference intervals developed using mass spectrometry

The aim of this study was to perform a systematic review of the published literature to determine the available serum/plasma steroid reference intervals generated by mass spectrometry (MS) methods across all age groups in healthy subjects and to suggest recommendations to achieve common MS based reference intervals for serum steroids. MEDLINE, EMBASE and PubMed databases were used to conduct a comprehensive search for English language, MS-based reference interval studies for serum/plasma steroids. Selection of steroids to include was based on those listed in the Royal College of Pathologists of Australasia Quality Assurance Programs, Chemical Pathology, Endocrine Program. This methodology has been registered onto the PROSPERO International prospective register of systematic reviews (ID number: CRD42015029637). After accounting for duplicates, a total of 60 manuscripts were identified through the search strategy. Following critical evaluation, a total of 16 studies were selected. Of the 16 studies, 12 reported reference intervals for testosterone, 11 for 17 hydroxy-progesterone, nine for androstenedione, six for cortisol, three for progesterone, two for dihydrotestosterone and only one for aldosterone and dehydroepiandrosterone sulphate. No studies established MS-based reference intervals for oestradiol. As far as we are aware, this report provides the first comparison of the peer reviewed literature for serum/plasma steroid reference intervals generated by MS-based methods. The reference intervals based on these published studies can be used to inform the process to develop common reference intervals, and agreed reporting units for mass spectrometry based steroid methods.

Aging and sex hormones in males

Several large cohort studies have disclosed the trajectories of sex steroids changes overtime in men and their clinical significance. In men the slow, physiological decline of serum testosterone (T) with advancing age overlaps with the clinical condition of overt, pathological hypogonadism. In addition, the increasing number of comorbidities, together with the high prevalence of chronic diseases, all further contribute to the decrease of serum T concentrations in the aging male. For all these reasons both the diagnosis of late-onset hypogonadism (LOH) in men and the decision about starting or not T replacement treatment remain challenging. At present, the biochemical finding of T deficiency alone is not sufficient for diagnosing hypogonadism in older men. Coupling hypogonadal symptoms with documented low serum T represents the best strategy to refine the diagnosis of hypogonadism in older men and to avoid unnecessary treatments.

Harmonized Reference Ranges for Circulating Testosterone Levels in Men of Four Cohort Studies in the United States and Europe

Background

Reference ranges for testosterone are essential for making a diagnosis of hypogonadism in men.

Objective

To establish harmonized reference ranges for total testosterone in men that can be applied across laboratories by cross-calibrating assays to a reference method and standard.

Population

The 9054 community-dwelling men in cohort studies in the United States and Europe: Framingham Heart Study; European Male Aging Study; Osteoporotic Fractures in Men Study; and Male Sibling Study of Osteoporosis.

Methods

Testosterone concentrations in 100 participants in each of the four cohorts were measured using a reference method at Centers for Disease Control and Prevention (CDC). Generalized additive models and Bland-Altman analyses supported the use of normalizing equations for transformation between cohort-specific and CDC values. Normalizing equations, generated using Passing-Bablok regression, were used to generate harmonized values, which were used to derive standardized, age-specific reference ranges.

Results

Harmonization procedure reduced intercohort variation between testosterone measurements in men of similar ages. In healthy nonobese men, 19 to 39 years, harmonized 2.5th, 5th, 50th, 95th, and 97.5th percentile values were 264, 303, 531, 852, and 916 ng/dL, respectively. Age-specific harmonized testosterone concentrations in nonobese men were similar across cohorts and greater than in all men.

Conclusion

Harmonized normal range in a healthy nonobese population of European and American men, 19 to 39 years, is 264 to 916 ng/dL. A substantial proportion of intercohort variation in testosterone levels is due to assay differences. These data demonstrate the feasibility of generating harmonized reference ranges for testosterone that can be applied to assays, which have been calibrated to a reference method and calibrator.

Current practices and challenges in the standardization and harmonization of clinical laboratory tests

Effective patient care, clinical research, and public health efforts require comparability of laboratory results independent of time, place, and measurement procedure. Comparability is achieved by establishing metrological traceability, which ensures that measurement procedures measure the same quantity and that the calibration of measurement procedures is traceable to a common reference system consisting of reference methods and materials. Whereas standardization ensures traceability to the International System of Units, harmonization ensures traceability to a reference system agreed on by convention. This article provides an overview of standardization and harmonization with an emphasis on commutability as an important variable that affects testing accuracy. Commutability of reference materials is required to ensure that traceability is established appropriately and that laboratory results are comparable. The use of noncommutable reference materials leads to inaccurate results. Whereas procedures and protocols for standardizing measurements are established and have been successfully applied in efforts such as the Hormones Standardization Program of the CDC, harmonization activities require new, more complex procedures and approaches. The American Association for Clinical Chemistry, together with its domestic and international partners, formed the International Consortium for Harmonization of Clinical Laboratory Results to coordinate harmonization efforts. Reference systems, as well as procedures and protocols to establish traceability of clinical laboratory tests, have been established and continue to be developed by national and international groups and organizations. Serum tests of thyroid function, including those for the thyroid hormones thyroxine and triiodothyronine, are among the clinical procedures for which standardization efforts are well under way. Approaches to the harmonization of measurement procedures for serum concentrations of thyroid-stimulating hormone are likewise under development.

Generation of Small Single Domain Nanobody Binders for Sensitive Detection of Testosterone by Electrochemical Impedance Spectroscopy

A phage display library of variable domain of the heavy chain only antibody or nanobody (Nb) was constructed after immunizing a bactrian camel with testosterone. With the smaller molecular size (15 kDa), improved solubility, good stability, high affinity, specificity, and lower immunogenicity, Nbs are a promising tool in the next generation of diagnosis and medical applications. Testosterone is a reproductive hormone, playing an important role in normal cardiac function and being the highly predictive marker for many diseases. Herein, a simple and sensitive immunosensor based on electrochemical impedance spectroscopy (EIS) and Nbs was successfully developed for the determination of testosterone. We successfully isolated the antitestosterone Nbs from an immune phage display library. Moreover, one of the Nbs was biotinylated according to in vivo BirA system, which showed the highest production yield and the most stable case. Further, the EIS immunosensor was set up for testosterone detection by applying the biotinylated antitestosterone Nb. As a result, the biosensor exhibited a linear working range from 0.05 to 5 ng mL(-1) with a detection limit of 0.045 ng mL(-1). In addition, the proposed immunosensor was successfully applied in determining testosterone in serum samples. In conclusion, the proposed immunosensor revealed high specificity of testosterone detection and showed as a potential approach for sensitive and accurate diagnosis of testosterone.

Effective Use of Mass Spectrometry in the Clinical Laboratory

BACKGROUND

Historically the success of mass spectrometry in the clinical laboratory has focused on drugs of abuse confirmations, newborn screening, and steroid analysis. Clinical applications of mass spectrometry continue to expand, and mass spectrometry is now being used in almost all areas of laboratory medicine.

CONTENT

A brief background of the evolution of mass spectrometry in the clinical laboratory is provided with a discussion of future applications. Prominent examples of mass spectrometry are covered to illustrate how it has improved the practice of medicine and enabled physicians to provide better patient care. With increasing economic pressures and decreasing laboratory test reimbursement, mass spectrometry testing has been shown to provide cost-effective solutions. In addition to pointing out the numerous benefits, the challenges of implementing mass spectrometry in the clinical laboratory are also covered.

SUMMARY

Mass spectrometry continues to play a prominent role in the field of laboratory medicine. The advancement of this technology along with the development of new applications will only accelerate the incorporation of mass spectrometry into more areas of medicine.

A microfluidic indirect competitive immunoassay for multiple and sensitive detection of testosterone in serum and urine

We demonstrate a microfluidic-based indirect competitive chemiluminescence enzyme immunoassay (MIC) for multiple, sensitive, reliable and rapid detection of testosterone in human serum and urine samples. As MIC can detect biomarkers in a cost-effective and easy-to-operate manner, it may have great potential for clinical diagnosis and point-of-care testing (POCT).

Serum Total Testosterone Concentrations in the US Household Population from the NHANES 2011-2012 Study Population

BACKGROUND

Limited information is available about testosterone concentrations representative of the general US population, especially children, women, and non-Hispanic Asians.

METHODS

We obtained nationally representative data for total testosterone (totalT), measured with standardized LC-MS/MS, for the US population age 6 years and older from the 2011-2012 National Health and Nutrition Examination Survey (NHANES). We analyzed 6746 serum samples and calculated the geometric means, distribution percentiles, and covariate-adjusted geometric means by age, sex, and race/ethnicity.

RESULTS

The 10th-90th percentiles of totalT values in adults (≥20 years) was 150-698 ng/dL (5.20-24.2 nmol/L) in men, 7.1-49.8 ng/dL (0.25-1.73 nmol/L) in women, and 1.0-9.5 ng/dL (0.04-0.33 nmol/L) in children (6-10 years old). Differences among race/ethnic groups existed in children and men: covariate-adjusted totalT values in non-Hispanic Asians were highest among children (58% compared to non-Hispanic black children) and lowest among men (12% compared to Mexican-American men). Covariate-adjusted totalT values in men were higher at age 55-60 years compared to ages 35 and 80 years, a pattern different from that observed in previous NHANES cycles.

CONCLUSIONS

TotalT patterns were different among age groups in men compared with previous NHANES cycles. Covariate-adjusted totalT values peaked at age 55-60 years in men, which appeared to be consistent with the increased use of exogenous testosterone. Differences among race/ethnic groups existed and appeared more pronounced in children than adults.

A review of the relationships between endogenous sex steroids and incident ischemic stroke and coronary heart disease events

For decades, it has been recognized that men have a higher age-adjusted risk of ischemic cardiovascular (CVD) events compared to women, thus generating hypotheses that sex steroids contribute to CVD risk. Potential mechanisms include genomic and non-genomic effects of sex steroids as well as mediation through classic CVD risk factors and obesity. However, results from randomized studies suggest that sex steroid supplementation in men and women do not result in improved CVD outcomes and may increase CVD risk. In contrast, prospective observations from endogenous sex steroid studies, i.e. among participants not using sex steroids, have suggested the opposite relationship. We reviewed the findings of prospective observational studies in men (17 studies) and women (8 studies) that examined endogenous sex steroids and CVD risk. These studies suggested a lack of association or that lower levels of testosterone or dihydrotestosterone are associated with higher CVD risk in both men and women. Higher, rather than lower, estradiol levels were associated with higher CVD risk in women. There were several significant gaps in the literature. First, it is unclear whether more sensitive measures of sex steroid levels might detect significant differences. Second, there are few prospective studies in women. Similarly, no studies report outcomes for high-risk groups such as African-Americans and Hispanics. Finally, few studies report upon ischemic coronary disease as opposed to ischemic stroke separately, although relationships between sex steroids and CVD may vary by vascular bed. Future investigations need to examine high risk groups and to distinguish between subtypes of CVD.