Tissue Glucocorticoid Metabolism in Adrenal Insufficiency: A Prospective Study of Dual-release Hydrocortisone Therapy

BACKGROUND

Patients with adrenal insufficiency (AI) require life-long glucocorticoid (GC) replacement therapy. Within tissues, cortisol (F) availability is under the control of the isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD). We hypothesize that corticosteroid metabolism is altered in patients with AI because of the nonphysiological pattern of current immediate release hydrocortisone (IR-HC) replacement therapy. The use of a once-daily dual-release hydrocortisone (DR-HC) preparation, (Plenadren®), offers a more physiological cortisol profile and may alter corticosteroid metabolism in vivo.

STUDY DESIGN AND METHODS

Prospective crossover study assessing the impact of 12 weeks of DR-HC on systemic GC metabolism (urinary steroid metabolome profiling), cortisol activation in the liver (cortisone acetate challenge test), and subcutaneous adipose tissue (microdialysis, biopsy for gene expression analysis) in 51 patients with AI (primary and secondary) in comparison to IR-HC treatment and age- and BMI-matched controls.

RESULTS

Patients with AI receiving IR-HC had a higher median 24-hour urinary excretion of cortisol compared with healthy controls (72.1 µg/24 hours [IQR 43.6-124.2] vs 51.9 µg/24 hours [35.5-72.3], P = .02), with lower global activity of 11β-HSD2 and higher 5-alpha reductase activity. Following the switch from IR-HC to DR-HC therapy, there was a significant reduction in urinary cortisol and total GC metabolite excretion, which was most significant in the evening. There was an increase in 11β-HSD2 activity. Hepatic 11β-HSD1 activity was not significantly altered after switching to DR-HC, but there was a significant reduction in the expression and activity of 11β-HSD1 in subcutaneous adipose tissue.

CONCLUSION

Using comprehensive in vivo techniques, we have demonstrated abnormalities in corticosteroid metabolism in patients with primary and secondary AI receiving IR-HC. This dysregulation of pre-receptor glucocorticoid metabolism results in enhanced glucocorticoid activation in adipose tissue, which was ameliorated by treatment with DR-HC.

Development and validation of a deep eutectic solvent-assisted liquid-liquid extraction method for simultaneous quantification of six steroid hormones in serum by liquid chromatography-tandem mass spectrometry

Steroid hormones have been reported to be associated with endocrine system diseases. This paper proposes a novel procedure of deep eutectic solvent (DES)-assisted liquid-liquid extraction (LLE) to extract six steroid hormones (including cortisone, cortisol, androstenedione, testosterone, 17-hydroxyprogesterone, and progesterone) from serum coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of five types of L-proline, choline chloride, and citric acid-based DESs were tailored; the DES from L-proline and ethylene glycol at a molar ratio of 1:4 with 20 % acetonitrile was selected as the best-fit assisted solvent for the six steroid hormones compared with other DESs. The parameters for extraction by selected DES were optimized using Box-Behnken design (BBD), and the optimal extraction conditions are 200 µL of acetonitrile, 100 µL of the sample, and 80 µL of DES. Under optimum conditions, the method has good linear calibration ranges (between 0.07 ng mL-1 and 600 ng mL-1), correlation coefficients of determination (r2>0.99), and low limits of quantification (between 0.02 and 0.60 ng mL-1). The extraction recoveries were in the range of 81.84-114.43 %, and the intra-day and inter-day relative standard deviations (RSDs) were less than 10 %.In general, the DES-LC-MS/MS method is a simple and environmentally-friendly method, which can be complementary to the presently available methods for determining steroid hormones in serum.

Serum cortisol assay performance following the 1 mg overnight dexamethasone suppression test

BACKGROUND

The 1 mg overnight dexamethasone suppression test (ONDST) is recommended for the differential diagnosis of Cushing's syndrome and the investigation of adrenal incidentalomas. Despite documented variation in serum cortisol immunoassay performance, little has been published regarding its effect on the ONDST.

AIMS

Assess the performance of three immunoassay platforms (Roche Elecsys II, Abbott Alinity & Siemens Centaur) when compared to a liquid chromatography tandem mass spectrometry (LC-MS/MS) method.

METHODS

Samples (n = 77) sent to the laboratory as part of an ONDST were retrieved prior to disposal, anonymized, and analysed on all platforms. Samples with factors impacting immunoassay analysis quality were excluded. Results were statistically compared to an LC-MS/MS method that previously demonstrated excellent comparability to a candidate reference method.

RESULTS

The Roche gen II showed a mean bias of -2.4 nmol/L and a Passing-Bablok fit of y = -0.9 + 0.97x. This was not affected by sex. The Abbott showed a mean bias -18.8 nmol/L, and a fit of y = -11.3 + 0.88x. This bias was -20.7 nmol/L in females versus -17.2 nmol/L in males. The Siemens had a mean bias of 2.3 nmol/L and a fit of y = 1.4 + 1.07x. This bias was 5.7 nmol/L in males versus -1.0 nmol/L in females.

CONCLUSIONS

Clinicians should be aware of the method-dependent variation that exists within serum cortisol analysis during the ONDSTs. Roche and Siemens aligned more closely with LC-MS/MS while the Abbot may cause a reduction in ONDST sensitivity. This data supports assay-specific cut-offs for the ONDST.

The Utility of Salivary Cortisone in the Overnight Dexamethasone Suppression Test in Adrenal Incidentalomas

CONTEXT

Guidelines recommend the assessment of cortisol secretion in patients with adrenal incidentalomas (AI) using the overnight dexamethasone suppression test (ONDST). This requires attendance at a health care facility and venepuncture. Alternatively, the ONDST can be done by measuring salivary cortisol and cortisone, which can be collected at home.

OBJECTIVE

We aimed to assess the utility of these measurements in patients with AI.

METHODS

A retrospective analysis of data from 173 patients with AI who underwent an ONDST and salivary cortisol/cortisone diurnal studies. Serum and salivary cortisol and salivary cortisone were collected at 09:00, late night, and at 09:00 the following morning after dexamethasone. Dexamethasone levels were measured in the postdexamethasone samples. Serum and salivary samples were analyzed with liquid chromatography-tandem mass spectrometry.

RESULTS

We identified a strong correlation between salivary cortisone and serum cortisol after 1 mg of dexamethasone (r = 0.95). Stepwise multivariate regression showed that postdexamethasone salivary cortisone, baseline serum cortisol, salivary cortisone suppression (predexamethasone/postdexamethasone ratio), and sex were the only significant or near-significant independent variables. Performance of predictive indices using these 4 parameters (sensitivity = 88.5%, specificity = 91.2%; kappa 0.80) and postdexamethasone salivary cortisone alone (sensitivity = 85.3%, specificity = 91.7%; kappa 0.77) were comparable when used to predict an ONDST serum cortisol of ≤50 nmol/L. No correlation was observed with any of the other measured parameters.

CONCLUSION

In AI patients, after dexamethasone, salivary cortisone correlates very strongly with serum cortisol in the ONDST and could therefore be used as an alternative sampling method which does not require venepuncture or attendance at hospital.

Urine metabolites for preoperative prediction of acute kidney injury after coronary artery bypass graft surgery

OBJECTIVE

Acute kidney injury is a common complication after on-pump coronary artery bypass grafting. Prediction of acute kidney injury remains a challenge. Our study aims to identify a panel of urine metabolites for preoperative warning of acute kidney injury after on-pump coronary artery bypass grafting.

METHODS

A total of 159 patients undergoing isolated on-pump coronary artery bypass grafting were enrolled from July 7, 2017, to May 17, 2019. Preoperative urine samples were analyzed with the approach of liquid chromatography-mass spectrometry-based urine metabolomics. The study end point was the episode of acute kidney injury within 48 hours postoperatively. The predictive performance was determined by the area under the curve and calibration curve. The results were validated using bootstrap resampling.

RESULTS

The acute kidney injury (n = 55) and nonacute kidney injury (n = 104) groups showed significant different metabolic profiling. A total of 28 metabolites showed significant differences between the acute kidney injury and nonacute kidney injury groups. A metabolite panel of 5 metabolites (tyrosyl-gamma-glutamate, deoxycholic acid glycine conjugate, 5-acetylamino-6-amino-3-methyluracil, arginyl-arginine, and L-methionine) was discovered to have a good predicting performance (area under the curve, 0.89; 95% confidence interval, 0.82-0.93), which is higher than the clinical factor-based model (area under the curve, 0.63; 95% confidence interval, 0.53-0.72). Internal validation by bootstrap resampling showed an adjusted area under the curve of 0.88, and the calibration curve demonstrated good agreement between prediction and observation in the probability of postoperative acute kidney injury. Decision curve analysis revealed a superior net benefit of the metabolite model over the traditional clinical factor-based model.

CONCLUSIONS

We present 5 urine metabolites related to acute kidney injury after coronary artery bypass grafting. This metabolite model may serve as a preoperative warning of acute kidney injury after on-pump coronary artery bypass grafting.

Clinical and Technical Aspects in Free Cortisol Measurement

Accurate measurement of cortisol is critical in adrenal insufficiency as it reduces the risk associated with misdiagnosis and supports the optimization of stress dose. Comprehensive assays have been developed to determine the levels of bioactive free cortisol and their clinical and analytical efficacies have been extensively discussed because the level of total cortisol is affected by changes in the structure or circulating levels of corticoid-binding globulin and albumin, which are the main reservoirs of cortisol in the human body. Antibody-based immunoassays are routinely used in clinical laboratories; however, the lack of molecular specificity in cortisol assessment limits their applicability to characterize adrenocortical function. Improved specificity and sensitivity can be achieved by mass spectrometry coupled with chromatographic separation methods, which is a cutting-edge technology to measure individual as well as a panel of steroids in a single analytical run. The purpose of this review is to introduce recent advances in free cortisol measurement from the perspectives of clinical specimens and issues associated with prospective analytical technologies.

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.

The effect of specific binding proteins on immunoassay measurements of total and free thyroid hormones and cortisol

BACKGROUND

Immunoassay (IA) measurements of thyroid hormones have previously given inaccurate results of triiodothyronine (T3), free triiodothyronine (FT3), and free thyroxine (FT4) when concentrations of TBG are low. We evaluate the hypothesis that abnormal concentrations of specific binding proteins (BPs) affect IA measurements and provide results which might misguide the diagnosis and treatment of patients. This study assesses IAs for the measurement of T3, FT3, and cortisol when levels of TBG and CBG are high or low. Comparisons are made between IA and LC-MS/MS.

METHODS

Serum or plasma samples with high (>95th percentile, n = 25) or low (<5th percentile, n = 27) concentrations of BP were collected. The concentrations of T3, FT3, and cortisol were measured by validated IA and liquid chromatography tandem mass spectrometry (LC-MS/MS) methods. Spearman correlation and Wilcoxon matched-pairs signed rank analyses were used to compare the two methods.

RESULTS

When TBG levels are <5th percentile, the differences between the IA and LC-MS/MS results for T3 and FT3 are statistically significant (T3, p = 0.0011; FT3, p = 0.0003). When CBG levels are >95th percentile, the difference between the IA and LC-MS/MS measurements of cortisol is statistically significant (p = <0.0001).

CONCLUSION

Abnormal BP concentrations appear to affect the accuracy of IA measurements of T3, FT3, and cortisol. The population of patients with either high or low levels of BPs is significant. Our samples reflect that 65% of women aged between 15 and 49 years are taking oral contraceptives in the US, and thus have elevated levels of BPs. In this group, IA results for cortisol are falsely low. Our samples reflect that patients with protein losing diseases have low BP concentrations. Among a group with renal complications, IA measurements of T3 are overestimated, while those of FT3 are underestimated. Are the Food and Drug Administration and diagnostic companies adequately assessing the accuracy of IA tests?

Quantitative MALDI-MS assay of steroid hormones in plasma based on hydroxylamine derivatization

Measuring the concentrations of steroid hormones in plasma is critical for understanding their role in various vital physiological processes. The detection of underivatized steroid hormones in biofluids through mass spectrometry (MS) is typically hindered by low ionization efficiency. We described a novel matrix-assisted laser desorption/ionization-MS (MALDI-MS) approach based on hydroxylamine derivatization (HA-D) to analyze low-concentration steroid hormones in plasma. The ketonic carbonyl group containing steroid hormones could be derivatized using HA to form oxime derivatives, which considerably enhanced the MS sensitivity for detecting steroid hormones. By using the optimized conditions, estrone (E1), testosterone (T), and progesterone (Prog), could be simultaneously quantified in plasma with a limit of detection (LOD) from 0.019 to 0.031 nM, recoveries from 86% to 108%, and coefficient of variation (CV%) from 4.59% to 11.90%. HA-D/MALDI-MS exhibited higher sensitivity than those using Girard T (GT). To establish potential utility of our method, we characterized fatty liver patient plasmas to demonstrate that the HA-D/MALDI-MS procedure could generate quantitative results comparable to the current clinical liquid chromatography-electrospray ionization tandem MS (LC-ESI MS/MS) method. This approach facilitates the rapid and accurate characterization of plasma hormones, and renders the MALDI-MS approach for steroid hormones more adaptable for clinical research and use.

The contribution of serum cortisone and glucocorticoid metabolites to detrimental bone health in patients receiving hydrocortisone therapy

BACKGROUND

Glucocorticoid therapy is the most common cause of iatrogenic osteoporosis. Less is known regarding the effect of glucocorticoids when used as replacement therapy on bone remodelling in patients with adrenal insufficiency. Enhanced intracellular conversion of inactive cortisone to active cortisol, by 11 beta-hydroxysteroid dehydrogenase type 1(11β-HSD1) and other enzymes leading to alterations in glucocorticoid metabolism, may contribute to a deleterious effect on bone health in this patient group.

METHODS

Study design: An open crossover prospective study randomizing ten hypopituitary men, with severe ACTH deficiency, to three commonly used hydrocortisone dose regimens.

MEASUREMENTS

Following 6 weeks of each regimen, patients underwent 24-h serum cortisol/cortisone sampling, measurement of bone turnover markers, and a 24-h urine collection for measurement of urinary steroid metabolites by gas chromatography-mass spectrometry (GC-MS). Serum cortisone and cortisol were analysed by liquid chromatography-mass spectrometry (LC-MS).

RESULTS

Dose-related and circadian variations in serum cortisone were seen to parallel those for cortisol, indicating conversion of ingested hydrocortisone to cortisone. The median area under the curve (AUC) of serum cortisone was significantly higher in patients on dose A (20 mg/10 mg) [670.5 (IQR 621-809.2)] compared to those on dose C (10 mg/5 mg) [562.8 (IQR 520.1-619.6), p = 0.01]. A negative correlation was observed between serum cortisone and bone formation markers, OC [1-49] (r = - 0.42, p = 0.03), and PINP (r = - 0.49, p = 0.01). There was a negative correlation between the AUC of night-time serum cortisone levels with the bone formation marker, OC [1-49] (r = - 0.41, p = 0.03) but there were no significant correlations between day-time serum cortisone or cortisol with bone turnover markers. There was a negative correlation between total urinary cortisol metabolites and the bone formation markers, PINP (r = - 0.39, p = 0.04), and OC [1-49] (r = - 0.35, p = 0.06).

CONCLUSION

Serum cortisol and cortisone and total urinary corticosteroid metabolites are negatively associated with bone turnover markers in patients receiving replacement doses of hydrocortisone, with nocturnal glucocorticoid exposure having a potentially greater influence on bone turnover.

TRIAL REGISTRATION

Irish Medicines Board Clinical Trial Number - CT900/459/1 and EudraCT Number - 2007-005018-37 . Registration date: 07-09-2007.

The diagnostic utility of late night salivary cortisol (LNSF) and cortisone (LNSE) in Cushing's syndrome

BACKGROUND

Measurement of late night salivary cortisol (LNSF) is useful in the identification of cyclical Cushing's syndrome (CS); the usefulness of its metabolite cortisone (late night salivary cortisone, LNSE) is less well described.

AIM

The aim of this study was to determine the utility of measuring LNSE in patients with confirmed CS compared with other diagnostic tests and to analyse serial LNSF measurements for evidence of variable hormonogenesis.

METHODS

This was a retrospective observational study including patients with confirmed CS in whom LNSF and LNSE were measured.

RESULTS

Twenty-three patients with confirmed CS were included, 21 with Cushing's disease. LNSF had a sensitivity of 92%, LNSE 87% and combined LNSF/LNSE 94% per sample. Four patients had cyclical hormonogenesis, when the definition of one trough and two peaks was applied to LNSF measurements, and a fifth patient fell just outside the criteria. Six patients had evidence of variable hormonogenesis, defined as doubling of LNSF concentration on serial measurements. Sensitivity of 24-h urinary free cortisol (UFC) was 89% per collection. Sixteen patients had simultaneous measurements of LNSF and UFC; in three patients, they provided discordant results.

CONCLUSION

LNSF appears more sensitive than LNSE and UFC in the diagnosis of CS, combining LNSF and LNSE results leads to superior sensitivity. Half of our cohort had evidence of cyclical or variable hormonogenesis. Fluctuations in LNSF did not always correlate with changes in UFC concentration, emphasising the importance of performing more than one screening test, particularly if pretest clinical suspicion is high.

Measurement of Salivary Adrenal-Specific Androgens as Biomarkers of Therapy Control in 21-Hydroxylase Deficiency

BACKGROUND

Monitoring of hormonal control represents a key part of the management of congenital adrenal hyperplasia (CAH). Monitoring strategies remain suboptimal because they rely on frequent blood tests and are not specific for adrenal-derived hormones. Recent evidence suggests the crucial role of adrenal-specific 11-oxygenated-C19 androgens in the pathogenesis of CAH.

OBJECTIVE

To establish a correlation between plasma and salivary adrenal-specific androgens in CAH as a noninvasive monitoring strategy.

DESIGN

This prospective cross-sectional study recruited patients between 2015 and 2018.

SETTING

Multicenter study including 13 tertiary centers in the United Kingdom.

PARTICIPANTS

Seventy-eight children with CAH and 62 matched healthy controls.

METHODS

Using liquid chromatography-tandem mass spectrometry, plasma and salivary concentrations of five steroids were measured: 17-hydroxyprogesterone (17OHP), androstenedione (A4), testosterone (T), 11-hydroxyandrostenedione (11OHA4), and 11-ketotestosterone (11KT). The correlation between plasma and salivary steroids was analyzed to assess their use in clinical practice.

RESULTS

Strong correlations between plasma and salivary steroid concentrations in patients with CAH were detected: 17OHP (rs = 0.871; P < 0.001), A4 (rs = 0.931; P < 0.001), T (rs = 0.867; P < 0.001), 11OH4A (rs = 0.876; P < 0.001), and 11KT (rs = 0.944; P < 0.001). These results were consistent for patient subgroups based on sex and age. Analysis of patient subgroups based on 17OHP concentrations established clear correlations between plasma and salivary concentrations of the adrenal-specific androgen 11KT.

CONCLUSIONS

The current study identified tight correlations between plasma and saliva for the adrenal-derived 11-oxygenated C19 androgen 11KT, as well as 17OHP and A4, which are widely used for monitoring treatment in CAH. This combination of steroid hormones will serve as an improved noninvasive salivary test for disease monitoring in patients with CAH.

Salivary Cortisone to Estimate Cortisol Exposure and Sampling Frequency Required Based on Serum Cortisol Measurements

CONTEXT

Population studies frequently measure cortisol as a marker of stress, and excess cortisol is associated with increased mortality. Cortisol has a circadian rhythm, and frequent blood sampling is impractical to assess cortisol exposure. We investigated measuring salivary cortisone and examined the sampling frequency required to determine cortisol exposure.

METHODS

Serum and saliva with cortisol and cortisone were measured by liquid chromatography-tandem mass spectrometry in independent cohorts. The relationship between serum cortisol and salivary cortisone was analyzed in cohort 1 using a linear mixed effects model. The resulting fixed effects component was applied to cohort 2. Saliva cannot easily be collected when a patient is sleeping, so we determined the minimum sampling required to estimate cortisol exposure [estimated area under the curve (eAUC)] using 24-hour cortisol profiles (AUC24) and calculated the relative error (RE) for eAUC.

RESULTS

More than 90% of variability in salivary cortisone could be accounted for by change in serum cortisol. A single serum cortisol measurement was a poor estimate of AUC24, especially in the morning or last thing at night (RE >68%); however, three equally spaced samples gave a median RE of 0% (interquartile range, -15.6% to 15.1%). In patients with adrenal incidentalomas, eAUC based on three serum cortisol samples showed a difference between those with autonomous cortisol secretion and those without (P = 0.03).

INTERPRETATION

Accepting that most people sleep 7 to 8 hours, ∼8-hourly salivary cortisone measurements provide a noninvasive method of estimating 24-hour cortisol exposure for population studies.

Accuracy of hydrocortisone dose administration via nasogastric tube

OBJECTIVE

Hydrocortisone via nasogastric (NG) tube is used in sick children with adrenal insufficiency; however, there is no licensed formulation for NG administration.

METHODS

We investigated hydrocortisone recovery after passage through NG tubes in vitro for three formulations: liquid suspension, crushed tablets mixed with water, and hydrocortisone granules designed for oral administration to children. Cortisol was measured by LC-MS/MS.

RESULTS

Hydrocortisone content was variable and recovery low after preparation in syringe and prior to passage through NG tubes. For doses, 0.5 and 2.0 mg mean percentage recovery was as follows: liquid suspension 57% and 58%; crushed tablets 46% and 30%; and hydrocortisone granules 78% and 71%. Flushing the administering syringe increased recovery. Hydrocortisone recovery after passage with flushing through 6-12Fr gauge NG tubes was variable: liquid suspension 61%-92%, crushed tablets 40%-174%, hydrocortisone granules 61%-92%. Administration of hydrocortisone granules occluded 6 and 8Fr NG tubes; however, administration using a sampling needle to prevent granules being administered gave a recovery of 74%-98%.

CONCLUSIONS

The administration of hydrocortisone through NG tubes is possible; however, current methods deliver a variable dose of hydrocortisone, generally less than that prescribed. Attention should be placed on the technique used to optimize drug delivery such as flushing of the administering syringe. Hydrocortisone granules block small NG tubes but behaved as well as the commonly used liquid suspension when prepared with a filtering needle that filters out granules.

Low salivary cortisol levels in patients with rheumatoid arthritis exposed to oral glucocorticoids: a cross-sectional study set within UK electronic health records

BACKGROUND

Glucocorticoids (GCs) suppress endogenous cortisol levels which can lead to adrenal insufficiency (AI). The frequency of GC-induced AI remains unclear. In this cross-sectional study, low morning salivary cortisol (MSC) levels were used as a measure of adrenal function. The study aim was to investigate the prevalence of low MSC in patients with rheumatoid arthritis (RA) currently and formerly exposed to oral GCs, and the association with potential risk factors.

METHODS

Sample collection was nested within UK primary care electronic health records (from the Clinical Practice Research Datalink). Participants were patients with RA with at least one prescription for oral GCs in the past 2 years. Self-reported oral GC use was used to define current use and current dose; prescription data were used to define exposure duration. MSC was determined from saliva samples; 5 nmol/L was the cut-off for low MSC. The prevalence of low MSC was estimated, and logistic regression was used to assess the association with potential risk factors.

RESULTS

66% of 38 current and 11 % of 38 former GC users had low MSC. Among former users with low MSC, the longest time since GC withdrawal was 6 months. Current GC dose, age and RA duration were significantly associated with increased risk of low MSC.

CONCLUSION

The prevalence of low MSC among current GC users is high, and MSC levels may remain suppressed for several months after GC withdrawal. Clinicians should therefore consider the risk of suppressed cortisol and remain vigilant for symptoms of AI following GC withdrawal.

Development of a rapid liquid chromatography tandem mass spectrometry method for the quantitation of serum dexamethasone and its clinical verification

Background Measurement of serum dexamethasone during the overnight dexamethasone-suppression test has been recommended to reduce false-positive results when investigating Cushing's syndrome or increasingly commonly found adrenal incidentalomas. Despite this, there remains a paucity of well-validated dexamethasone methods currently available. Here, we describe the development of a rapid and sensitive liquid chromatography tandem mass spectrometry serum dexamethasone assay and verify its utility in a cohort of postmenopausal females. Method Isotopically labelled internal standard was added to samples prior to supported liquid extraction. Extracts were analysed using liquid chromatography tandem mass spectrometry in the positive electrospray ionization mode. Multiple reaction monitoring was used to detect dexamethasone and its corresponding internal standard transitions. Normal healthy postmenopausal women ( n = 95) were recruited and underwent an overnight dexamethasone suppression test, with serum dexamethasone and cortisol measurements at 09:00 after administration of oral dexamethasone 1 mg at 23:00 the night before. Results Mean intra- and inter-assay imprecision were 4.1% and 2.9%, respectively, for dexamethasone concentrations of 1.5, 6.0 and 12.0 nmol/L. Matrix effects were found to be negligible at 106-109% with recovery ranging from 96 to 100%. The limit of quantitation was 0.25 nmol/L, and structural analogue analysis proved the method to be robust against interferences. Applying a serum dexamethasone cut-off of >3.3 nmol/L was associated with a serum cortisol ≤50 nmol/L in 84/95 individuals. Conclusion We have developed a sensitive and robust liquid chromatography tandem mass spectrometry method for the quantitation of serum dexamethasone. The method can be used to identify false-positive results during the overnight dexamethasone suppression test or for pharmacokinetic studies.

Bioavailability of Oral Hydrocortisone Corrected for Binding Proteins and Measured by LC-MS/MS Using Serum Cortisol and Salivary Cortisone

Context

The assessment absolute bioavailability of oral hydrocortisone is complicated by its saturable binding to cortisol binding globulin (CBG). Previous assessment of bioavailability used a cortisol radioimmunoassay which has cross reactivity with other steroids. Salivary cortisone is a measure of free cortisol and LC-MS/MS is the gold standard method for measuring steroids. We here report the absolute bioavailability of hydrocortisone calculated using serum cortisol and salivary cortisone measured by LC-MS/MS.

Methods

14 healthy male dexamethasone suppressed volunteers were administered 20 mg hydrocortisone either intravenously or orally by tablet. Samples of serum and saliva were taken and measured for cortisol and cortisone by LC-MS/MS. Serum cortisol was corrected for saturable binding using published data and pharmacokinetic parameters derived using the program WinNonlin.

Results

The mean (95% CI) bioavailability of oral hydrocortisone calculated from serum cortisol, unbound serum cortisol and salivary cortisone was 1.00 (0.89-1.14); 0.88 (0.75-1.05); and 0.93 (0.83-1.05), respectively.

Conclusion

The data confirm that, after oral administration, hydrocortisone is completely absorbed. The data derived from serum cortisol corrected for protein binding, and that from salivary cortisone, are similar supporting the concept that salivary cortisone reflects serum free cortisol levels and that salivary cortisone can be used as a non-invasive method for measuring the pharmacokinetics of hydrocortisone.

Biochemistry of the menopause

The life of a human female is characterized from teenage years by monthly menstruation which ceases (the menopause) typically between the age of 40 and 60 years. The potential for reproduction declines and ceases as the ovaries become depleted of follicles. A transition period in mid-life, for 2 to 10 years, when menstruation is less regular is called the perimenopause. The menopause is associated with a significant decline in plasma concentrations of sex hormones, an increase in the concentrations of the gonadotrophins and changes in other hormones such as the inhibins. These changes are superimposed with effects of aging, social and metabolic factors, daily activity and well-being. Although the menopause is entirely natural, in some cases ovarian failure can occur earlier than usual; this is pathological and warrants careful biochemical investigations to distinguish it from conditions causing infertility. Elderly females are affected by a range of clinical disorders including endocrine, cardiovascular, skeletal, urogenital tract and immunological systems, body mass, vasomotor tone, mood and sleep pattern. Reference intervals for many diagnostic biochemical tests for the menopause need to be used when interpreting results in clinical investigations for patient management. The standardization and harmonization of assays are being addressed. Many women now choose to develop their career before bearing children, and the health service has had to change services around this. This review does not cover screening for and tests during pregnancy. The review is timely since the population is aging and there will be more demand on healthcare services.

Characterization of Cortisol Secretion Rate in Secondary Adrenal Insufficiency

Context:

In secondary adrenal insufficiency (SAI), chronic deficiency of adrenocorticotropin (ACTH) is believed to result in secondary changes in adrenocortical function, causing an altered dose-response relationship between ACTH concentration and cortisol secretion rate (CSR).

Objective:

We sought to characterize maximal cortisol secretion rate (CSR_max) and free cortisol half-life in patients with SAI, compare results with those of age-matched healthy controls, and examine the influence of predictor variables on ACTH-stimulated cortisol concentrations.

Design:

CSR_max was estimated from ACTH_1-24 (250 μg)_–stimulated cortisol time-concentration data. Estimates for CSR_max and free cortisol half-life were obtained for both dexamethasone (DEX) and placebo pretreatment conditions for all subjects.

Setting:

Single academic medical center.

Patients:

Patients with SAI (n = 10) compared with age-matched healthy controls (n = 21).

Interventions:

The order of DEX vs placebo pretreatment was randomized and double-blind. Cortisol concentrations were obtained at baseline and at intervals for 120 minutes after ACTH_1-24.

Main Outcome Measures:

CSR_max and free cortisol half-life were obtained by numerical modeling analysis. Predictors of stimulated cortisol concentrations were evaluated using a multivariate model.

Results:

CSR_max was significantly (P < 0.001) reduced in patients with SAI compared with controls for both placebo (0.17 ± 0.09 vs 0.46 ± 0.14 nM/s) and DEX (0.18 ± 0.13 vs 0.43 ± 0.13 nM/s) conditions. Significant predictors of ACTH_1-24–stimulated total cortisol concentrations included CSR_max, free cortisol half-life, and baseline total cortisol, corticosteroid-binding globulin, and albumin concentrations (all P < 0.05).

Conclusions:

Our finding of significantly decreased CSR_max confirms that SAI is associated with alterations in the CSR-ACTH dose-response curve. Decreased CSR_max contributes importantly to the laboratory diagnosis of SAI.

Steroid metabolome analysis reveals prevalent glucocorticoid excess in primary aldosteronism

BACKGROUND

Adrenal aldosterone excess is the most common cause of secondary hypertension and is associated with increased cardiovascular morbidity. However, adverse metabolic risk in primary aldosteronism extends beyond hypertension, with increased rates of insulin resistance, type 2 diabetes, and osteoporosis, which cannot be easily explained by aldosterone excess.

METHODS

We performed mass spectrometry-based analysis of a 24-hour urine steroid metabolome in 174 newly diagnosed patients with primary aldosteronism (103 unilateral adenomas, 71 bilateral adrenal hyperplasias) in comparison to 162 healthy controls, 56 patients with endocrine inactive adrenal adenoma, 104 patients with mild subclinical, and 47 with clinically overt adrenal cortisol excess. We also analyzed the expression of cortisol-producing CYP11B1 and aldosterone-producing CYP11B2 enzymes in adenoma tissue from 57 patients with aldosterone-producing adenoma, employing immunohistochemistry with digital image analysis.

RESULTS

Primary aldosteronism patients had significantly increased cortisol and total glucocorticoid metabolite excretion (all P < 0.001), only exceeded by glucocorticoid output in patients with clinically overt adrenal Cushing syndrome. Several surrogate parameters of metabolic risk correlated significantly with glucocorticoid but not mineralocorticoid output. Intratumoral CYP11B1 expression was significantly associated with the corresponding in vivo glucocorticoid excretion. Unilateral adrenalectomy resolved both mineralocorticoid and glucocorticoid excess. Postoperative evidence of adrenal insufficiency was found in 13 (29%) of 45 consecutively tested patients.

CONCLUSION

Our data indicate that glucocorticoid cosecretion is frequently found in primary aldosteronism and contributes to associated metabolic risk. Mineralocorticoid receptor antagonist therapy alone may not be sufficient to counteract adverse metabolic risk in medically treated patients with primary aldosteronism.

FUNDING

Medical Research Council UK, Wellcome Trust, European Commission.

Measuring cortisol in serum, urine and saliva - are our assays good enough?

Cortisol is a steroid hormone produced in response to stress. It is essential for maintaining health and wellbeing and leads to significant morbidity when deficient or present in excess. It is lipophilic and is transported bound to cortisol-binding globulin (CBG) and albumin; a small fraction (∼10%) of total serum cortisol is unbound and biologically active. Serum cortisol assays measure total cortisol and their results can be misleading in patients with altered serum protein concentrations. Automated immunoassays are used to measure cortisol but lack specificity and show significant inter-assay differences. Liquid chromatography - tandem mass spectrometry (LC-MS/MS) offers improved specificity and sensitivity; however, cortisol cut-offs used in the short Synacthen and Dexamethasone suppression tests are yet to be validated for these assays. Urine free cortisol is used to screen for Cushing's syndrome. Unbound cortisol is excreted unchanged in the urine and 24-h urine free cortisol correlates well with mean serum-free cortisol in conditions of cortisol excess. Urine free cortisol is measured predominantly by immunoassay or LC-MS/MS. Salivary cortisol also reflects changes in unbound serum cortisol and offers a reliable alternative to measuring free cortisol in serum. LC-MS/MS is the method of choice for measuring salivary cortisol; however, its use is limited by the lack of a single, validated reference range and poorly standardized assays. This review examines the methods available for measuring cortisol in serum, urine and saliva, explores cortisol in disease and considers the difficulties of measuring cortisol in acutely unwell patients and in neonates.

Endogenous glucocorticoid analysis by liquid chromatography-tandem mass spectrometry in routine clinical laboratories

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful analytical technique that offers exceptional selectivity and sensitivity. Used optimally, LC-MS/MS provides accurate and precise results for a wide range of analytes at concentrations that are difficult to quantitate with other methodologies. Its implementation into routine clinical biochemistry laboratories has revolutionised our ability to analyse small molecules such as glucocorticoids. Whereas immunoassays can suffer from matrix effects and cross-reactivity due to interactions with structural analogues, the selectivity offered by LC-MS/MS has largely overcome these limitations. As many clinical guidelines are now beginning to acknowledge the importance of the methodology used to provide results, the advantages associated with LC-MS/MS are gaining wider recognition. With their integral role in both the diagnosis and management of hypo- and hyperadrenal disorders, coupled with their widespread pharmacological use, the accurate measurement of glucocorticoids is fundamental to effective patient care. Here, we provide an up-to-date review of the LC-MS/MS techniques used to successfully measure endogenous glucocorticoids, particular reference is made to serum, urine and salivary cortisol.

Serum Cortisol: An Up-To-Date Assessment of Routine Assay Performance

BACKGROUND

Accurate serum cortisol quantification is required for the correct diagnosis and management of adrenal pathologies. Presently, most laboratories use immunoassay to measure serum cortisol with proficiency schemes demonstrating a wide dispersion of results. Here, we investigate the effects of sex, matrix, and antibody specificity on serum cortisol quantification in 6 routine assays.

METHODS

Surplus serum was obtained before disposal and the following cohorts were created: males, nonpregnant females, pregnant patients, and patients prescribed either metyrapone or prednisolone. Samples were anonymized and distributed to collaborating laboratories for cortisol analysis by 6 routine assays. Cortisol was also measured in all samples using an LC-MS/MS candidate reference measurement procedure (cRMP); cortisol-binding globulin (CBG) was measured in the nonpregnant and pregnant female cohorts.

RESULTS

Considerable inter- and intraassay variation was observed across the male and nonpregnant female cohorts relative to the cRMP. Four immunoassays underrecovered cortisol in the pregnancy cohort, and CBG was found to be significantly higher in this cohort than in the nonpregnant females. In the metyrapone and prednisolone cohorts, all immunoassays overestimated cortisol. The first generation Roche E170 and Siemens Centaur XP were particularly prone to overestimation. In all cohorts the routine LC-MS/MS assay aligned extremely well with the cRMP.

CONCLUSIONS

Despite the clinical importance of serum cortisol, the performance of routine immunoassays remains highly variable. Accurate quantification is compromised by both matrix effects and antibody specificity. Underpinning this study with a cRMP has highlighted the deficiencies in standardization across routine cortisol immunoassays.

Salivary Cortisone Reflects Cortisol Exposure Under Physiological Conditions and After Hydrocortisone

In this study we tested the use of salivary cortisol and cortisone as alternatives to serum cortisol. Salivary cortisol is often undetectable and contaminated by hydrocortisone. Salivary cortisone strongly reflects serum cortisol.

Candidate Reference Measurement Procedure for the Quantification of Total Serum Cortisol with LC-MS/MS

BACKGROUND

Accurate measurement of serum cortisol is required to diagnose and treat adrenal disorders. Although certified reference materials (CRMs) are available to standardize cortisol measurements, External Quality Assessment (EQA) schemes still demonstrate a wide dispersion of results. We present a serum cortisol candidate reference measurement procedure that, through analysis of a Joint Committee for Traceability in Laboratory Medicine–listed panel of higher-order CRMs, provides metrologically traceable results.

METHOD

Isotope-labeled internal standard was added to samples before supported liquid extraction. Extracts were analyzed with LC-MS/MS in positive electrospray ionization mode. Multiple reaction monitoring was used to detect cortisol and its corresponding internal standard transitions. We measured samples in triplicate over 3 days and calculated the mean result.

RESULTS

Mean intra- and interassay imprecision were 1.3% and 1.5%, respectively, for concentrations of 154, 510, and 769 nmol/L. Ionization efficiency studies and structural analog analysis proved the method to be robust against interferences. Through analysis of 34 CRMs (83–764 nmol/L), expanded measurement uncertainty was calculated to be 5% (95% CI). The mean bias between the measured and target CRM concentrations was statistically insignificant at −0.08%.

CONCLUSIONS

The accuracy and low measurement uncertainty of this method qualify it as a CRM procedure. Metrological traceability has been achieved through the analysis of higher-order CRMs. This method could be used to underpin serum cortisol EQA schemes to provide samples with a traceable target value, enabling participating laboratories to determine the accuracy and measurement uncertainty of their assays.

A Novel 'Dilute-and-Shoot' Liquid Chromatography-Tandem Mass Spectrometry Method for the Screening of Antihypertensive Drugs in Urine

Arterial hypertension is one of the most preventable causes of premature morbidity and mortality with resistant hypertension reported to be present in 5-30% of the total hypertensive population. Despite the poor prognosis, as many as 53% of those with resistant hypertension are reported to be nonadherent to their prescribed medication. An objective test of adherence, which is easy to administer, quick, inexpensive and reliable, is therefore needed to identify patients with true resistance to antihypertensive drugs to optimize their treatment. We have developed a novel LC-MS-MS method for the detection of 23 commonly prescribed antihypertensive medications in urine. The validated method was subsequently applied to the analysis of urine from a cohort of 49 individuals who were taking at least one antihypertensive agent in the screening profile to determine their adherence. The screening method was found to be reproducible, sensitive and specific with the limit of detection ranging from 0.1 to 1.0 µg/L. Sample preparation is rapid (30 s) and simple, with a total analysis time of 11 min. The assay successfully identified the majority of drugs our cohort had admitted to taking (88%) with drugs not detected in urine, potentially indicating nonadherence to prescribed medication. The performance of this simple, robust LC-MS-MS procedure is suitable for screening urine for the presence of commonly prescribed antihypertensive medications. The assay, which can easily be implemented in other laboratories, has the potential to significantly improve investigation and management of resistant hypertension.

Mass spectrometry and immunoassay: how to measure steroid hormones today and tomorrow

The recent onslaught of mass spectrometry (MS) to measurements of steroid hormones, including demands that they should be the only acceptable method, has confused clinicians and scientists who have relied for more than 40 years on a variety of immunoassay (IA) methods in steroid hormone measurements. There is little doubt that MS methods with their superior specificity will be the future method of choice in many clinical and research applications of steroid hormone measurement. However, the majority of steroid measurements are currently, and will continue to be, carried out using various types of IAs for several reasons, including their technical ease, cost and availability of commercial reagents. Speedy replacement of all IAs with MS is an unrealistic and unnecessary goal, because the availability of MS measurements is limited by cost, need of expensive equipment, technical demands and lack of commercial applications. Furthermore, IAs have multiple well-known advantages that vindicate their continuing use. The purpose of this article is to elucidate the advantages and limitations of the MS and IA techniques from two angles, i.e. promotion of MS and defence of IA. The purpose of the text is to give the reader an unbiased view about the current state and future trends of steroid analysis and to help him/her choose the correct assay method to serve his/her diagnostic and research needs.

Liquid chromatography tandem mass spectrometry in the clinical laboratory

Clinical laboratory medicine has seen the introduction and evolution of liquid chromatography tandem mass spectrometry in routine clinical laboratories over the last 10–15 years. There still exists a wide diversity of assays from very esoteric and highly specialist manual assays to more simplified kit-based assays. The technology is not static as manufacturers are continually making improvements. Mass spectrometry is now commonly used in several areas of diagnostics including therapeutic drug monitoring, toxicology, endocrinology, paediatrics and microbiology. Some of the most high throughput analyses or common analytes include vitamin D, immunosuppressant monitoring, androgen measurement and newborn screening. It also offers flexibility for the measurement of analytes in a variety of different matrices which would prove difficult with immunoassays. Unlike immunoassays or high-pressure liquid chromatography assays using ultraviolet or fluorescence detection, mass spectrometry offers better specificity and reduced interferences if attention is paid to potential isobaric compounds. Furthermore, multiplexing, which enables multiple analytes to be measured with the same volume of serum is advantageous, and the requirement for large sample volumes is decreasing as instrument sensitivity increases. There are many emerging applications in the literature. Using mass spectrometry to identify novel isoforms or modified peptides is possible as is quantification of proteins and peptides, with or without protein digests. Future developments by the manufacturers may also include mechanisms to improve the throughput of samples and strategies to decrease the level of skill required by the operators.

LC–MS/MS in endocrinology: what is the profit of the last 5 years?

Currently, chromatography (GC but more commonly HPLC) is the analytical method of choice for several hormones, either because the immunoassays suffer from extensive crossreactivity or because chromatography permits simultaneous measurements of hormones. However, sometimes the conventional detection systems with HPLC methods do not meet desired specificity. With the increase of robust and affordable LC–MS/MS systems, the next step forward in specificity was taken. LC–MS/MS is rapidly being incorporated in the endocrine laboratories. To be useful in the clinical diagnostic practice, it is of utmost importance that methods are both analytically and clinically vaidated, as until now, the majority of applications of LC–MS/MS in the clinical laboratories are ‘home-made’ methods, therefore special case must be taken. This review aims to focus on Clinical and Laboratory Standards Institute or comparable validated LC–MS/MS methods for targeted hormone analysis used for diagnostic purposes in human samples, published in the last 5 years.

The effect of serum matrix and gender on cortisol measurement by commonly used immunoassays

Background

Considerable intermethod bias has been observed between cortisol immunoassays, with some also displaying a gender difference. Cortisol immunoassay performance is affected by serum matrix effects such as changes in steroid binding proteins and presence of interfering steroids which can be altered in various clinical settings. This study investigates cortisol immunoassay bias in pregnancy, renal failure and intensive care patients.

Methods

Serum remaining after routine analysis from pregnant patients, patients on the intensive care unit and patients with renal failure were obtained prior to disposal and used to create 20 anonymous samples per group. A male and female serum pool was prepared and spiked with cortisol. Samples were aliquoted and distributed to four hospitals for cortisol analysis by immunoassays from four different manufacturers. Cortisol was also measured by an isotope dilution-gas chromatography–mass spectrometry method for comparison of assay bias.

Results

Differences in cortisol immunoassay bias were observed across the different patient groups. A negative bias compared to pooled serum samples was observed for pregnancy serum, whilst a more positive bias was seen in renal failure and intensive care patients. Variation in bias was greatest in renal failure with the Roche E170 the most affected and the Abbott architect the least (interquartile ranges 44% and 14%, respectively).

Conclusions

Cortisol immunoassay bias may be affected by gender and differences in serum matrix from patients with various clinical conditions. Users of cortisol assays should be aware of differing matrix effects on their assay and the relevance of these for the interpretation of clinical results.

Novel liquid chromatography tandem mass spectrometry (LC-MS/MS) methods for measuring steroids

Liquid chromatography tandem mass spectrometry (LC-MS/MS) is increasingly becoming the method of choice for steroid hormone measurements due to small sample volumes, fast analysis times and improved specificity compared to immunoassays. Achievement of demanding analytical targets for steroid analysis is now becoming possible because of improvements in sample preparation technology, liquid chromatography column technology and mass spectrometer design. The most popular sample treatment strategies comprise protein precipitation (PP), solid-phase extraction (SLE) and liquid-liquid extraction (LLE). Modern liquid chromatography columns can ensure the adequate separation of isobaric compounds e.g. 21 Deoxycortisol, 11 Deoxycortisol and Corticosterone. The most appropriate method may be chosen to improve assay sensitivity by reducing matrix effects (LLE, SPE) or simplicity and speed (PP). Specific examples of some clinically important steroids including oestradiol, aldosterone, renin, serum cortisol, salivary cortisol and salivary testosterone will be described.