Steroid profiles using liquid chromatography-tandem mass spectrometry with atmospheric pressure photoionization source

Pediatric reference intervals for aldosterone, 17alpha-hydroxyprogesterone, dehydroepiandrosterone, testosterone and 25-hydroxy vitamin D3 using tandem mass spectrometry

OBJECTIVES

To determine age and sex-specific pediatric reference intervals for aldosterone, 17alpha-hydroxyprogesterone, dehydroepiandrosterone, testosterone, and 25-hydroxy vitamin D(3).

BACKGROUND AND DESIGN

Reference intervals were determined for neonates and children 0-18 years of age. The study was conducted at both Children's National Medical Center and Georgetown University using outpatient blood samples obtained between January 1, 2004 and June 30, 2008.

METHODS

Serum samples were analyzed using isotope dilution liquid chromatography tandem mass spectrometry (LC/MS/MS) with deuterium-labeled internal standards at Children's National Medical Center and Georgetown University Medical Center Bioanalytical Core Laboratory.

RESULTS AND CONCLUSIONS

This is the first study to provide pediatric reference intervals of steroid hormones for children from birth to 18 years of age using LC/MS/MS. Reference intervals were established for aldosterone, 17alpha-hydroxyprogesterone, dehydroepiandrosterone, testosterone, and 25-hydroxy vitamin D(3). All the analytes exhibited at least some age dependence. Sex differences between early and late childhood and adolescence were found for 17alpha-hydroxyprogesterone and testosterone. Seasonal differences were apparent for 25-hydroxy vitamin D(3).

Simultaneous quantitation of seven endogenous C-21 adrenal steroids by liquid chromatography tandem mass spectrometry in human serum

Quantitation of endogenous steroids is important in the diagnosis of several endocrine disorders. In this study we present a new method for simultaneous quantitation of cortisol, cortisone, 11-desoxycortisol, 21-desoxycortisol, corticosterone, 17-hydroxyprogesterone and 11-desoxycorticosterone in human serum by on-line extraction and LC-MS/MS. Analytes extraction was performed on-line using a 2-position and 6-port valve equipped with a monolithic silica cartridge. After chromatographic separation of all analytes, detection was performed in the multiple reaction monitoring mode using positive atmospheric pressure chemical ionization mode. Total imprecision of the assay ranged from 5.5 to 15.5%. Comparison with immunoassays yielded coefficients of 0.893 for cortisol, 0.848 for 11-desoxycortisol and 0.924 for 17-hydroxyprogesterone. The sensitivity of this method provides meaningful data for patients within normal and elevated range and it may be useful for the diagnosis of a variety of adrenal dysfunctions.

Challenges in translating plasma proteomics from bench to bedside: update from the NHLBI Clinical Proteomics Programs

The emerging scientific field of proteomics encompasses the identification, characterization, and quantification of the protein content or proteome of whole cells, tissues, or body fluids. The potential for proteomic technologies to identify and quantify novel proteins in the plasma that can function as biomarkers of the presence or severity of clinical disease states holds great promise for clinical use. However, there are many challenges in translating plasma proteomics from bench to bedside, and relatively few plasma biomarkers have successfully transitioned from proteomic discovery to routine clinical use. Key barriers to this translation include the need for "orthogonal" biomarkers (i.e., uncorrelated with existing markers), the complexity of the proteome in biological samples, the presence of high abundance proteins such as albumin in biological samples that hinder detection of low abundance proteins, false positive associations that occur with analysis of high dimensional datasets, and the limited understanding of the effects of growth, development, and age on the normal plasma proteome. Strategies to overcome these challenges are discussed.

Adrenocortical hormone abnormalities in men with chronic prostatitis/chronic pelvic pain syndrome

OBJECTIVES

To identify adrenocortical hormone abnormalities as indicators of endocrine dysfunction in chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS).

METHODS

We simultaneously measured the serum concentrations of 12 steroids in patients with CP/CPPS and controls, using isotope dilution liquid chromatography, followed by atmospheric pressure photospray ionization and tandem mass spectrometry.

RESULTS

We evaluated 27 patients with CP/CPPS and 29 age-matched asymptomatic healthy controls. In the mineralocorticoid pathway, progesterone was significantly greater, and the corticosterone and aldosterone concentrations were significantly lower, in the patients with CP/CPPS than in the controls. In the glucocorticoid pathway, 11-deoxycortisol was significantly lower and the cortisol concentrations were not different between the patients and controls. In the sex steroid pathway, the androstenedione and testosterone concentrations were significantly greater in those with CP/CPPS than in the controls. The estradiol, dehydroepiandrosterone, and dehydroepiandrosterone sulfate concentrations were not different between the patients and controls. The National Institutes of Health-Chronic Prostatitis Symptom Index total and pain domain scores correlated positively with the 17-hydroxyprogesterone and aldosterone (P <0.001) and negatively with the cortisol (P <0.001) concentrations.

CONCLUSIONS

Our results suggest reduced activity of CYP21A2 (P450c21), the enzyme that converts progesterone to corticosterone and 17-hydroxyprogesterone to 11-deoxycortisol. Furthermore, these results provide insights into the biologic basis of CP/CPPS. Follow-up studies should explore the possibility that patients with CP/CPPS meet the diagnostic criteria for nonclassic congenital adrenal hyperplasia and whether the hormonal findings improve or worsen in parallel with symptom severity.

Rapid measurement of estrogens and their metabolites in human serum by liquid chromatography-tandem mass spectrometry without derivatization

OBJECTIVES

The steroids estradiol (E2), estrone (E1), and estriol (E3) are the major estrogens. E1/E2 and their metabolite 16-hydroxyestrone (16-OHE1, known to be carcinogenic) could be involved in the development of many cancers including human breast cancer. The aim of the current study was to develop a rapid and simple high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) assay to simultaneously measure E1, E2, E3 and 16-OHE1 in human serum without the need for solid phase extraction or derivatization.

METHODS

An API-5000 triple-quadrupole mass spectrometer coupled with electrospray ionization (ESI) source and Shimadzu HPLC system was used employing isotope dilution with deuterium-labeled internal standard (IS) for each analyte. Quantitation by multiple reaction monitoring (MRM) analysis was performed in negative ion mode.

RESULTS

The limits of detection were 1.0 pg/mL for E1 and 16-OHE1 and 2.0 pg/mL for E2 and E3. Within-day CVs were <6.5% for all analytes tested and between-day CVs ranged from 4.5% to 9.5%. Recovery ranged from 88% to 108%.

CONCLUSION

This method allows for the simultaneous measurement of four estrogens in human serum within 8 min. It can be routinely employed in a clinical environment and is attractive because of its simplicity in sample processing, micro sample requirement, and high throughput.

Fast and direct quantification of adrenal steroids by tandem mass spectrometry in serum and dried blood spots

We present a fast and reproducible method for steroid analysis (corticosterone, deoxycorticosterone, progesterone, 17alpha-hydroxyprogesterone, 11-deoxycortisol, 21-deoxycortisol, androstenedione, testosterone, dihydrotestosterone and cortisol) in small volumes of serum and in dried blood spot samples by LC-MS/MS. No derivatisation was needed. LC separation was achieved by using an Atlantis C18 column and water-methanol-formic acid gradient as a mobile phase and a flow rate of 250 microL/min over a run time of 6 min. Steroids were measured in MRM mode with electrospray interface (positive ion mode). Validation showed excellent precision, sensitivity, recovery and linearity with coefficients of determination r2>0.992.

Steroid profiles in serum by liquid chromatography-tandem mass spectrometry in infants with genital hair

BACKGROUND

In recent years, an increasing number of infants have been seen with fine hair in the genital area and no other signs of androgen excess, but the hormonal basis of this finding is unknown.

AIM

To compare steroid profiles in infants with genital hair with age-matched control infants, using liquid chromatography-tandem mass spectrometry (LC-TMS) to measure eight steroids (cortisol, 11-deoxycortisol, progesterone, 17-hydroxyprogesterone, testosterone, androstenedione, DHEA, and DHEA-S).

PATIENTS

Samples were obtained between 1/04 and 12/05 from infants with genital hair, and for comparison, a group of 5-9 year-olds with premature adrenarche, as well as control children of similar ages being seen for thyroid problems or short stature.

RESULTS

Steroid profiles in infants with genital hair were similar to those in control infants, except that DHEA-S levels were somewhat higher (17.5 vs. 7.6 microg/dl [476 vs. 207 nmol/l]; p = 0.067), and six of 12 had levels >15 microg/dl (408 nmol/l) vs. one of 12 controls. Testosterone levels were low (<10 ng/dl [<350 pmol/l) in nearly all infants with pubic hair; the main exception was a girl whose father used topical testosterone (31 ng/dl [1076 pmol/l]). Genital hair disappeared in two patients over time but persisted for 6 months to 2 years in most.

CONCLUSIONS

No pathological increase in steroid levels was found in infants with genital hair vs controls, though a mild elevation of DHEA-S was seen in about half. This suggests that pubic hair in infancy may represent a mild and early onset variant of premature adrenarche, with a benign clinical course.

Trace determination of steroids causing age-related diseases using LC/MS combined with detection-oriented derivatization

With the rapid shift to an aging society in Japan, age-related diseases, such as osteoporosis, dementia and cancer, are sharply increasing. The measurement of steroids related to these diseases in biological fluids and tissues is useful for elucidation of the nature, diagnosis and treatment of such diseases. LC/MS is considered to be the most promising method for this purpose due to its specificity and versatility, but it sometimes does not demonstrate the required sensitivity for trace amounts of steroids, because steroids have a rather low response using either electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI). To overcome this problem, the author developed detection-oriented derivatization procedures for steroids in LC/MS. For ESI-MS, introduction of a permanently charged moiety is effective. Based on this, 2-hydrazino-1-methylpyridine was developed and used in monitoring prostatic 5alpha-dihydrotestosterone, a good index for the follow-up of patients affected by prostate cancer under androgen deprivation therapy and salivary dehydroepiandrosterone, which is now often designated as an anti-aging hormone. A proton-affinitive Cookson-type reagent, 4-[2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalyl)ethyl]-1,2,4-triazoline-3,5-dione, was used for the determination of 1alpha-hydroxyvitamin D3 [1alpha(OH)D3], a synthetic prodrug of the active form of vitamin D3, in human plasma, and this new LC/positive-APCI-MS method enabled the pharmacokinetic study of 1alpha(OH)D3 in humans. Electron-capture APCI-MS based on derivatization with 2-nitro-4-trifluoromethylphenylhydrazine was used for the analysis of neurosteroids, which affect brain excitability through action at the neurotransmitter receptors. With this method, the stress-induced rapid biosynthesis of pregnane-type neurosteroids in rat brains was demonstrated.

Use of steroid profiles in determining the cause of adrenal insufficiency

HYPOTHESIS

A cortisol response to adrenocorticotropin injection is the standard test for diagnosing adrenal insufficiency. Multiple steroid hormones can now be accurately measured by tandem mass spectrometry in a single sample. The study objective was to determine whether a steroid profile, created by simultaneous measurement of 10 steroid hormones by tandem mass spectrometry, would help determine the cause of adrenal insufficiency.

DESIGN

A 10-steroid profile was measured by tandem mass spectrometry during the performance of a standard high dose cortrosyn stimulation test. The steroids were measured at baseline, 30, and 60min following synthetic adrenocorticotropin injection. Adrenal insufficiency was defined as a peak cortisol level of less than 20microg/dL. Testing was conducted in the general clinical research center of a university medical center. Normal volunteers, patients suspected of having adrenal insufficiency, and patients with known adrenal insufficiency participated.

RESULTS

Our results showed that adrenal insufficiency of any cause was adequately diagnosed using the response of 11-deoxycortisol, dehydroepiandrosterone, or these analytes combined in a two-steroid profile. A three-steroid profile yielded a test with 100% accuracy for discriminating primary adrenal insufficiency from normal status. Primary adrenal insufficiency was well separated from secondary adrenal insufficiency using only a single aldosterone value. 11-Deoxycortisol, dehydroepiandrosterone, and a two-steroid profile each provided fair discrimination between secondary adrenal insufficiency and normal status.

CONCLUSIONS

We conclude that stimulated levels of aldosterone, 11-deoxycortisol, dehydroepiandrosterone, and a two- or three-steroid profile provided additional discrimination between states of adrenal sufficiency and insufficiency. It is proposed that a steroid profile measuring cortisol, aldosterone, 11-deoxycortisol, and dehydroepiandrosterone would potentially improve the ability to determine the cause of adrenal insufficiency.

Studies on neurosteroids XIX. Development and validation of liquid chromatography-tandem mass spectrometric method for determination of 5alpha-reduced pregnane-type neurosteroids in rat brain and serum

A sensitive liquid chromatography-electrospray ionization-tandem mass spectrometric (LC-ESI-MS-MS) method for the simultaneous determination of 5alpha-reduced pregnan-type neurosteroids, allopregnanolone (AP), epiallopregnanolone and 5alpha-dihydroprogesterone, in rat brain and serum has been developed and validated. The brain and serum steroids were extracted with methanol-acetic acid, purified using a Strata-X cartridge, derivatized with the permanently charged reagent, 2-hydrazino-1-methylpyridine (HMP), and subjected to LC-positive ESI-MS-MS. The limits of quantitation (LOQ) for brain (0.25 ng/g tissue) and serum (0.25 ng/ml) assays using the derivatization-ESI-MS-MS method are 60-150-fold lower than the LOQs for their atmospheric pressure chemical ionization-MS method without derivatization. [17Alpha,21,21,21-2H4]-AP was used as an internal standard. This method allowed the reproducible and accurate quantification of the brain or serum neurosteroids using a 20 mg or 20 microl sample, respectively. That is, the intra- and inter-assay coefficients of variation were below 8.2 and 6.0%, respectively, and the % accuracy values were 98.5-103.0% for all the steroids in both the brain and serum. The application of the developed method to the analysis of changes in the brain and serum neurosteroid levels by immobilization stress and ethanol administration is also presented.

Simultaneous determination of 12 steroids by isotope dilution liquid chromatography-photospray ionization tandem mass spectrometry

BACKGROUND

Serum steroid assays play an important role in the clinical evaluation of a number of common endocrine disorders. Among various assays, tandem mass spectrometry (MS/MS) has being increasingly applied in clinical laboratories for its high sensitivity, specificity, and simultaneous multi-analyte quantitation capability. Our first generation isotope dilution steroid profile assay by HPLC-tandem MS/MS with a C-18 column allowed for the measurement of 9 steroids in 18 min employing a sample volume of 760 ul serum. We describe our second generation steroid profile assay which allows for the quantitation of 12 steroids simultaneously employing HPLC-MS/MS and isotope dilution tandem MS in 11 min. This method requires a sample volume of 200 microl.

METHODS

An API-5000 triple-quadrupole mass spectrometer (Sciex, Concord, Canada) coupled with the PhotoSpray source and Shimadzu HPLC system (Shimadzu Scientific Instruments, Columbia, MD) was used employing isotope dilution with deuterium labeled internal standard (IS) for each analyte. Two hundred microliters of serum were deproteinized by adding 300 microl of acetonitrile containing internal standards. After centrifugation, 450 microl of supernatant were diluted with 900 microl of water and 1000 microl aliquot were injected onto a C-8 column. After a 3 min wash the valve was activated to initiate the gradient elution program which eluted the steroids. Quantitation by MRM analysis was performed both in positive ion mode for 11 analytes and in negative ion mode for aldosterone. Within-day and between-day precision, reliability and accuracy of this method were assessed by correlation with other MS/MS and immunoassay methods and by recovery study.

RESULTS

Within-day CVs were <11.5% for all analytes tested and between-day CVs ranged from 3.5% to 12.2%. The results of the comparison study yield r values ranging between 0.908 and 0.999. Recovery ranged from 90% to 110%.

CONCLUSIONS

This method can simultaneously measure 12 steroids in serum within 11 min with minimal sample preparation. It can be routinely employed in a clinical environment and is attractive because of its simplicity in sample processing and high throughput.

Steroid hormone levels in pregnancy and 1 year postpartum using isotope dilution tandem mass spectrometry

OBJECTIVE

To establish normal, trimester-specific reference intervals for serum 17beta-estradiol, progesterone (P), 17alpha-hydroxyprogesterone, cortisol, 11-deoxycortisol, androstenedione, DHEA, and DHEAS, measured simultaneously using isotope dilution tandem mass spectrometry.

DESIGN

Sequential cohort study.

PATIENT(S)

Healthy women undergoing a normal pregnancy (age, 25-38 years; mean, 30 years) attending a prenatal well clinic at gestation weeks 12, 22, and 32 and approximately 1 year postpartum.

MAIN OUTCOME MEASURE(S)

Trimester-specific reference intervals of endogenous steroid hormones analyzed using an isotope dilution tandem mass spectrometer equipped with an atmospheric pressure photoionization source with deuterium-labeled internal standards.

RESULT(S)

Serum estradiol, P, 17alpha-hydroxyprogesterone, and 11-deoxycortisol increased throughout pregnancy; cortisol increased up to the second trimester and then remained steady, while androstenedione increased by 80 percent by gestation week 12, then remained constant. Serum DHEA-S decreased by 50% by the third trimester.

CONCLUSION(S)

Trimester-specific reference intervals are reported for eight serum steroids. The ratios of individual serum hormone concentrations during pregnancy relative to their 1-year postpartum concentrations illustrate the expected normal trends of changes in hormone concentrations during pregnancy.

From fundamentals to applications: recent developments in atmospheric pressure photoionization mass spectrometry

Only five years after the first publication on atmospheric pressure photoionization (APPI), this technique has evolved rapidly as a very useful complement to established ionization techniques for liquid chromatography/mass spectrometry (LC/MS). This is reflected in a rapidly increasing number of publications in this field. On the one hand, thorough studies into the photoionization mechanism have provided deep insights into the roles and influences of the solvent, the dopant and other additives. On the other hand, a large number of new and attractive applications have recently been introduced. New instrumental developments have resulted in combined APPI/ESI (PAESI) and APPI/APCI sources and a microfabricated APPI source. In this review, the most important developments within the field are summarized, focusing in particular on the applications of the technique.

Pediatric reference intervals for FSH, LH, estradiol, T3, free T3, cortisol, and growth hormone on the DPC IMMULITE 1000

BACKGROUND

We studied serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), triiodothyronine (T3), free T3 (FT3), cortisol and growth hormone (GH) concentrations in a population of pediatric patients. The reference intervals were determined separately for females and males stratified by age groups to assess age- and sex-related differences. Our objective was to obtain reference intervals for the 7 serum analytes for our pediatric population using the IMMULITE 1000 system.

METHODS

Serum samples of 800 in- and out-patients, newborn to 19 years old were analyzed using the DPC IMMULITE 1000 chemiluminescent immunoassay system.

RESULTS AND CONCLUSIONS

We report pediatric reference intervals for FSH, LH, E2, T3, FT3, cortisol, and GH. These reference intervals provide the basis for clinical interpretation of laboratory results using the IMMULITE 1000 system and the assessment of child development.

Rapid measurement of plasma acylcarnitines by liquid chromatography–tandem mass spectrometry without derivatization

BACKGROUND

Tandem mass spectrometry (MS/MS) is being increasingly used to identify and measure acylcarnitines in blood and urine of children suspected of having fatty oxidation disorders and other inborn errors of metabolism. Rapid MS/MS analysis requires simple and efficient sample preparation. We developed a LC-MS/MS method for the online extraction of acylcarnitines in plasma without derivatization that requires only precipitation of proteins by acetonitrile followed by centrifugation, thus increasing efficiency.

METHODS

An API-3000 tandem mass spectrometer (SCIEX, Toronto, Canada) equipped with electrospray ionization (ESI), TurboIon Spray source, three Shimadzu LC10AD micropumps and autosampler (Shimadzu Scientific Instruments, Columbia, MD) was used to perform the analysis. Within-day and between-day imprecision was evaluated for 10 analytes in the MRM mode using 3 levels of controls. Accuracy was determined by comparing the method with another MS/MS procedure and by recovery experiments. Sensitivity and specificity were evaluated by identifying patient samples under a wide variety of clinical conditions.

RESULTS

Within-day CVs was <10% for all analytes tested and between-day CVs ranged from 4.4% to 14.2%. The method was linear in the range between 1.0 and 100 micromol/l for C2 and 0.1 and 10 micromol/l for the other acylcarnitines. The results of the comparison study yielded r values ranging between 0.948 and 0.999. Recovery ranged from 84% to 112%. The method correctly identified patients with a variety of fatty acid oxidation disorders and organic acidemias.

CONCLUSIONS

Our method is a simple procedure for the analysis of acylcarnitines in plasma with minimal sample preparation. It is thus ideal in a routine clinical setting where efficient processing of clinical samples is necessary to reduce turnaround time under conditions of high-throughput.