Maik Welzel

Implementation of a Liquid Chromatography Tandem Mass Spectrometry Assay for Eight Adrenal C-21 Steroids and Pediatric Reference Data

Background: Sensitive and accurate determination of steroids is essential for diagnosing congenital and acquired adrenal diseases. Since plasma concentrations change during childhood, age-specific reference ranges are the prerequisite for clinical interpretation. The objectives of this study were to develop a sensitive and reliable method for simultaneous detection and quantification of progesterone, 17-hydroxyprogesterone, deoxycorticosterone (DOC), 11-deoxycortisol, 21-deoxycortisol, corticosterone, cortisol (F) and cortisone (E) by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) and to establish age- and sex-specific reference ranges from birth to adulthood. Methods: All eight steroids were measured simultaneously in 0.1 ml plasma by UPLC-MS/MS. Samples of 905 children were measured and grouped in five age groups. Results: The assay was linear up to 70 ng/ml (700 ng/ml for F; r2 > 0.992). The limit of detection ranged between 0.01 ng/ml for DOC and 0.07 ng/ml for E. Correlations with radioimmunoassays yielded a coefficient of determination between 0.82 and 0.99. Reference data are reported as a function of age and sex. Conclusions: The UPLC-MS/MS method presented here for the simultaneous detection of eight C-21 adrenal hormones together with the detailed reference ranges for children provides a valuable methodology for assessing adrenal steroids in clinical routine and research.

Steroid Hormone Profiles in Prepubertal Obese Children Before and After Weight Loss

CONTEXT Little information is available on the steroid hormone profiles in obese children and their changes after weight loss. OBJECTIVE We compared liquid chromatography-tandem mass spectrometry of serum steroid hormone profiles between obese and normal-weight children and studied the differential effects of weight loss on these hormones. DESIGN This study was a cross-sectional comparison between obese and normal-weight children and a longitudinal 1-year follow-up study during lifestyle intervention in obese children. SETTING The setting of the study was primary care. PATIENTS Forty obese prepubertal (mean age 8.5 ± 2.1 years, 48% female, mean body mass index 24.8 ± 3.5 kg/m(2)) and 40 normal-weight children matched for gender, age, and pubertal stage. INTERVENTION The study consisted of an outpatient 1-year intervention program based on exercise, behavior, and nutrition therapy. MAIN OUTCOMES MEASURES Progesterone, 17-hydroxyprogesterone, 11-deoxycorticosterone, corticosterone, aldosterone, 11-deoxycortisol, cortisol, cortisone, dehydroepiandrosterone sulfate (DHEAS), androstenedione, T, dihydrotestosterone, insulin resistance index of the homeostasis model assessment, and blood pressure were measured. RESULTS Prepubertal obese children showed significantly increased androgens (DHEAS, androstenedione, T), mineralocorticoid precursor corticosterone, and glucocorticoids (11-deoxycortisol, cortisol, cortisone) compared with normal-weight children. In contrast to 20 obese children without weight loss, the 20 obese children with substantial weight loss demonstrated a significant decrease of cortisol, cortisone, and corticosterone. Androstenedione and T decreased but DHEAS remained elevated. Changes of the homeostasis model assessment correlated significantly positively with changes of cortisol (r = 0.38) and cortisone (r = 0.43) in partial regression analyses adjusted to changes of weight status. CONCLUSIONS In obese prepubertal children, the increased androgens, mineralocorticoid precursors, and glucocorticoids were responsive to weight loss in contrast to DHEAS, suggesting that DHEAS does not seem to be regulated by changes in body mass index.

Principles and clinical applications of liquid chromatography — tandem mass spectrometry for the determination of adrenal and gonadal steroid hormones

Liquid-chromatography — tandem mass spectrometry (LC-MS/MS) is becoming the method of choice for clinical steroid analysis. In most instances, it has the advantage of higher sensitivity, better reproducibility and greater specificity than commercial immunoassay techniques. The method requires only minimal sample preparation and a small sample volume. Furthermore, it has the potential to analyze multiple steroids simultaneously. Modern instruments guarantee high throughput, allowing an affordable price for the individual assay. All this makes LC-MS/MS an attractive method for use in a clinical setting. Reliable reference ranges for the detected analytes are the pre-requisite for their clinical use. If these are available, LC-MS/MS can find application in congenital disorders of steroid metabolism, such as congenital adrenal hyperplasia, disorders of sex development and disorders of salt homeostasis, as well as in acquired disorders of steroid metabolism, such as primary aldosteronism, Cushing’s disease, Addison’s disease, and hyperandrogenemia, as well as in psychiatric disease states such as depression or anxiety disorders. The principles of LC-MS/MS for steroid measurement, the pros and cons of LC-MS/MS compared with conventional immunoassays and the possible applications in clinical routine, with a special focus on pediatric endocrinology needs, are discussed here.

Relationships Between 24-Hour Urinary Free Cortisol Concentrations and Metabolic Syndrome in Obese Children

CONTEXT Clinical features of Metabolic Syndrome (MetS) and Cushings Syndrome are similar, suggesting a pathogenetic role of hypothalamus-pituitary-adrenal axis in MetS. OBJECTIVE The aim of the study was to determine whether MetS diagnosis and specific clusters of MetS components (waist circumference, dyslipidemia, hypertension, and impaired glucose metabolism) are associated with serum cortisol (SC) or 24-h urinary free cortisol (UFC) levels. DESIGN AND SETTING We conducted cross-sectional analyses of data from our obesity cohort. We studied 264 obese children (age, 11.0 ± 2.8 years; male, 48%; BMI, 28.2 ± 5.4 kg/m(2)). We examined UFC, SC, homeostasis model assessment (HOMA), and features of MetS (waist circumference, blood pressure, fasting lipids, and glucose). RESULTS Slightly increased UFC concentrations were measured in 30.7% of the children. Obese children with MetS had significantly (P = .003) higher UFC levels compared with obese children without MetS. Girls demonstrated significantly higher UFC concentrations compared with boys independent of pubertal stage. UFC and SC levels were significantly related to features of MetS, but the associations were stronger for UFC. In multivariate analyses adjusted for age, sex, and body mass index, none of the features of MetS but HOMA index was correlated with UFC, whereas SC demonstrated no significant association to any parameter of MetS or HOMA. CONCLUSIONS Our findings support the hypothesis that changes in the hypothalamus-pituitary-adrenal axis are related to MetS in obesity. UFC seems to be a suitable marker for this relationship. Norm values for UFC adapted to obese children may help to avoid unnecessary dexamethasone suppression tests.

No Correlation between Androgen Receptor CAG and GGN Repeat Length and the Degree of Genital Virilization in Females with 21-Hydroxylase Deficiency

CONTEXT In 21-hydroxylase (CYP21A2) deficiency (21OHD), the level of in vitro enzymatic function allows for classification of mutation groups (null, A, B, C) and prediction of disease severity. However, genital virilization in affected females correlates only weakly with CYP21A2 mutation groups, suggesting the influence of genetic modifiers. OBJECTIVE The objective of the study was to investigate the influence of the polymorphic CAG and GGn repeats of the androgen receptor (AR) gene on the degree of genital virilization in 21OHD females. DESIGN AND PATIENTS Design of the study was the determination of CYP21A2 genotype, degree of genital virilization (Prader stage), and X-weighted biallelic mean of AR CAG and GGn repeat length in 205 females with 21OHD. OUTCOME MEASUREMENTS Correlation of AR CAG and GGn repeat lengths with Prader stages using nested stepwise logistic regression analysis was measured. RESULTS CYP21A2 mutation groups null and A showed significantly higher levels of genital virilization than groups B and C (P < 0.01). However, Prader stages varied considerably within mutation groups: null, Prader I-V (median IV); A, Prader I-V (median IV); B, Prader I-V (median III); C, 0-III (median I). Mean GGn repeat length of patients was not significantly associated with Prader stages, classified as low (0-I), intermediate (II-III), or severe (IV-V) (odds ratio per repeat: 0.98, 95% confidence interval 0.71-1.35). In contrast, patients with Prader 0-I showed a trend toward longer CAG repeats without reaching statistical significance (P = 0.07, odds ratio per repeat: 0.82, 95% confidence interval 0.65-1.02). CONCLUSION Neither CAG nor GGn repeat lengths are statistically significant modifiers of genital virilization in females with 21OHD.

Five novel mutations in the SCNN1A gene causing autosomal recessive pseudohypoaldosteronism type 1

BACKGROUND Pseudohypoaldosteronism type 1 (PHA1) is a monogenic disease caused by mutations in the genes encoding the human mineralocorticoid receptor (MR) or the α (SCNN1A), β (SCNN1B) or γ (SCNN1G) subunit of the epithelial Na(+) channel (ENaC). While autosomal dominant mutation of the MR cause renal PHA1, autosomal recessive mutations of the ENaC lead to systemic PHA1. In the latter, affected children suffer from neonatal onset of multi-organ salt loss and often exhibit cystic fibrosis-like pulmonary symptoms. OBJECTIVE We searched for underlying mutations in seven unrelated children with systemic PHA1, all offsprings of healthy consanguineous parents. METHODS AND RESULTS Amplification of the SCNN1A gene and sequencing of all 13 coding exons unraveled mutations in all of our patients. We found five novel homozygous mutations (c.587_588insC in two patients, c.1342_1343insTACA, c.742delG, c.189C>A, c.1361-2A>G) and one known mutation (c.1474C>T) leading to truncation of the αENaC protein. All parents were asymptomatic heterozygous carriers of the respective mutations, confirming the autosomal recessive mode of inheritance. Five out of seven patients exhibited pulmonary symptoms in the neonatal period. CONCLUSION The α subunit is essential for ENaC function and mutations truncating the pore-forming part of the protein leading to systemic PHA1. Based on current knowledge, the pulmonary phenotype cannot be satisfactorily predicted.

The novel mutation p.Trp147Arg of the steroidogenic acute regulatory protein causes classic lipoid congenital adrenal hyperplasia with adrenal insufficiency and 46,XY disorder of sex development.

Background: The steroidogenic acute regulatory protein (StAR) is essential for steroidogenesis by mediating cholesterol transfer into mitochondria. Inactivating StAR mutations cause lipoid congenital adrenal hyperplasia. Objective and Methods: To identify causative mutations in a patient presenting with adrenal failure during early infancy. The objective was to study the functional and structural consequences of the novel StAR mutation p.Trp147Arg in a Turkish patient detected in compound heterozygosity with the p.Glu169Lys mutation. Results: Transient in vitro expression of the mutant proteins together with P450 side-chain cleavage enzyme, adrenodoxin, and adrenodoxin reductase yielded severely diminished cholesterol conversion of the p.Trp147Arg mutant. The previously described p.Glu169Lys mutant led to significantly lower cholesterol conversion than wild-type StAR protein. As derived from three-dimensional protein modeling, the residue W147 is stabilizing the C-terminal helix in a closed conformation hereby acting as gatekeeper of the ligand cavity of StAR. Conclusions: The novel mutation p.Trp147Arg causes primary adrenal insufficiency and complete sex reversal in the 46,XY patient. Clinical disease, in vitro studies and three-dimensional protein modeling of the mutation p.Trp147Arg underscore the relevance of this highly conserved residue for StAR protein function.

17α-Hydroxylase Deficiency Diagnosed in Early Infancy Caused by a Novel Mutation of the CYP17A1 Gene

Background: Mutations of the CYP17A1 gene cause 17α-hydroxylase deficiency (17OHD) resulting in 46,XY disorder of sex development, hypertension, hypokalemia and absent pubertal development. It is a rare, autosomal recessive form of congenital adrenal hyperplasia (CAH). Patient: We report on a neonate with prenatally determined 46,XY karyotype. At 20 weeks of gestation, lack of development of male external genitalia was noticed. A phenotypically female child was born at 41 weeks of gestation. Results: Postnatal ultrasound revealed testes in both labia majora, an absence of uterus and normal adrenal glands. Steroid hormone analysis in serum revealed low basal levels of cortisol, testosterone and androstenedione in the presence of massively elevated corticosterone at the age of 2 weeks. The urinary steroid profile from spot urine showed excessive excretion of 17-desoxysteroids, decreased glucocorticoid metabolites and absent C19 steroids, thus proving 17OHD. Molecular analysis identified a novel mutation of the CYP17A1 gene: c.896T>A (p.I299N) in exon 5. Substitution with hydrocortisone was started. The child is raised as a girl and is developing well so far. Conclusion: Herein, we report the unusually early diagnosis of a newborn with the rare CAH form of 17OHD allowing an early start of treatment.

Transcriptional response of peripheral blood mononuclear cells to recombinant human growth hormone in a routine four-days IGF-I generation test

BACKGROUND There are very few laboratory markers which reflect the biological sensitivity of children to recombinant human growth hormone (rhGH) treatment. Genome-wide transcriptional changes in peripheral blood mononuclear cells (PBMC) have been widely used as functional readout for different pharmacological stimuli. OBJECTIVE To characterize transcriptional changes in PBMC induced by rhGH during a routine short-term IGF-I generation test (IGFGT) in children with growth disorders. MATERIALS AND METHODS Blood was obtained for IGF-I determination and RNA-preparation from PBMC of 12 children before and after 4days treatment with 30μgrhGH/kg body weight/day s.c. Transcriptional changes were assessed by cDNA-microarrays in the first six children. Selected genes were validated in all 12 cases by RT-qPCR. RESULTS Serum IGF-I rose in all patients except one (p<0.0001), confirming biological response to rhGH. Unsupervised microarray data analysis in the first six children revealed 313 transcripts with abundant transcriptional changes but considerable inter-individual variability of response patterns. Many patients showed a large cluster of up-regulated genes, including EGR1, EGR2, FOS and to a lesser extent STAT2 and 5b. Exemplarily, EGR1, EGR2 and FOS data were independently reproduced by RT-qPCR. Gene ontology analysis revealed that pathways involved in cell proliferation and immune functions were significantly over represented. CONCLUSION The IGFGT is a suitable method for measuring reproducible and biologically conclusive transcriptional changes in PBMC. As our unsupervised data analysis strategy exposed a considerable inter-individual variability of response profiles a search for molecules of diagnostic and even prognostic value needs to be based on large long-term studies.

In vivo Investigations of the Effect of Short- and Long-Term Recombinant Growth Hormone Treatment on DNA-Methylation in Humans

Treatment with recombinant human growth hormone (rhGH) has been consistently reported to induce transcriptional changes in various human tissues including peripheral blood. For other hormones it has been shown that the induction of such transcriptional effects is conferred or at least accompanied by DNA-methylation changes. To analyse effects of short term rhGH treatment on the DNA-methylome we investigated a total of 24 patients at baseline and after 4-day rhGH stimulation. We performed array-based DNA-methylation profiling of paired peripheral blood mononuclear cell samples followed by targeted validation using bisulfite pyrosequencing. Unsupervised analysis of DNA-methylation in this short-term treated cohort revealed clustering according to individuals rather than treatment. Supervised analysis identified 239 CpGs as significantly differentially methylated between baseline and rhGH-stimulated samples (p<0.0001, unadjusted paired t-test), which nevertheless did not retain significance after adjustment for multiple testing. An individualized evaluation strategy led to the identification of 2350 CpG and 3 CpH sites showing methylation differences of at least 10% in more than 2 of the 24 analyzed sample pairs. To investigate the long term effects of rhGH treatment on the DNA-methylome, we analyzed peripheral blood cells from an independent cohort of 36 rhGH treated children born small for gestational age (SGA) as compared to 18 untreated controls. Median treatment interval was 33 months. In line with the groupwise comparison in the short-term treated cohort no differentially methylated targets reached the level of significance in the long-term treated cohort. We identified marked intra-individual responses of DNA-methylation to short-term rhGH treatment. These responses seem to be predominately associated with immunologic functions and show considerable inter-individual heterogeneity. The latter is likely the cause for the lack of a rhGH induced homogeneous DNA-methylation signature after short- and long-term treatment, which nevertheless is well in line with generally assumed safety of rhGH treatment.