Publications by authors named "Jana Malikova"

17 Publications

  • Page 1 of 1

Novel presentation of the c.1856A > G (p.Asp619Gly) TSHR gene-activating variant: relapsing hyperthyroidism in three subsequent generations manifesting in early childhood and an in vitro functional study.

Hormones (Athens) 2021 Jun 18. Epub 2021 Jun 18.

Vera Vavrova Laboratory/VIAL, Department of Pediatrics, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic.

Background: Familial non-autoimmune hyperthyroidism is a rare disease caused by germline activating variants in the thyroid-stimulating hormone receptor (TSHR) gene. The c.1856A > G (p.Asp619Gly) pathogenic variant has been described in cases of toxic adenoma but never before, to our knowledge, in a case of familial non-autoimmune hyperthyroidism.

Patient Findings: A 3-year-old boy was admitted for acute gastroenteritis presenting with goiter and tall stature. Laboratory findings revealed peripheral hyperthyroidism and negativity for thyroid autoantibodies. Antithyroid drug treatment was effective, but relapses occurred shortly after attempts to decrease the drug dose. As the boy's father and paternal grandmother also experienced relapsing hyperthyroidism manifesting in early childhood, genetic testing of TSHR was indicated. The c.1856A > G (p.Asp619Gly) pathogenic variant was found in all three affected family members. Functional in vitro characterization of the variant verified that it enhances constitutional activation of the receptor, leading to increased production of cyclic adenosine monophosphate. Total thyroidectomy was indicated in the boy due to an unsatisfactory prognosis. Due to persistent positive thyroglobulin serum concentration, a diagnostic radioiodine scan was performed approximately 2 years later. Residual thyroid tissue was revealed; therefore, radioiodine ablative therapy was performed. Despite adequate thyroxine substitution over a long period of follow-up, TSH remained suppressed.

Conclusions: Unlike Graves' disease, familial non-autoimmune hyperthyroidism cases present with antithyroid drug-dependence. Not ultrasound but positive thyroglobulin serum concentration indicated residual thyroid tissue. Early detection of residual thyroid tissue and radioiodine ablation prevented the subject from experiencing relapsing hyperthyroidism and undergoing unnecessary repeated surgery. Life-long hormone substitution should be adjusted to free thyroxine rather than TSH serum concentrations.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
June 2021

Disease characteristics of MCT8 deficiency: an international, retrospective, multicentre cohort study.

Lancet Diabetes Endocrinol 2020 07;8(7):594-605

Department of Diabetes and Endocrinology, Women's and Children's Hospital, North Adelaide, SA, Australia.

Background: Disordered thyroid hormone transport, due to mutations in the SLC16A2 gene encoding monocarboxylate transporter 8 (MCT8), is characterised by intellectual and motor disability resulting from cerebral hypothyroidism and chronic peripheral thyrotoxicosis. We sought to systematically assess the phenotypic characteristics and natural history of patients with MCT8 deficiency.

Methods: We did an international, multicentre, cohort study, analysing retrospective data from Jan 1, 2003, to Dec 31, 2019, from patients with MCT8 deficiency followed up in 47 hospitals in 22 countries globally. The key inclusion criterion was genetically confirmed MCT8 deficiency. There were no exclusion criteria. Our primary objective was to analyse the overall survival of patients with MCT8 deficiency and document causes of death. We also compared survival between patients who did or did not attain full head control by age 1·5 years and between patients who were or were not underweight by age 1-3 years (defined as a bodyweight-for-age Z score <-2 SDs or <5th percentile according to WHO definition). Other objectives were to assess neurocognitive function and outcomes, and clinical parameters including anthropometric characteristics, biochemical markers, and neuroimaging findings.

Findings: Between Oct 14, 2014, and Jan 17, 2020, we enrolled 151 patients with 73 different MCT8 (SLC16A2) mutations. Median age at diagnosis was 24·0 months (IQR 12·0-60·0, range 0·0-744·0). 32 (21%) of 151 patients died; the main causes of mortality in these patients were pulmonary infection (six [19%]) and sudden death (six [19%]). Median overall survival was 35·0 years (95% CI 8·3-61·7). Individuals who did not attain head control by age 1·5 years had an increased risk of death compared with patients who did attain head control (hazard ratio [HR] 3·46, 95% CI 1·76-8·34; log-rank test p=0·0041). Patients who were underweight during age 1-3 years had an increased risk for death compared with patients who were of normal bodyweight at this age (HR 4·71, 95% CI 1·26-17·58, p=0·021). The few motor and cognitive abilities of patients did not improve with age, as evidenced by the absence of significant correlations between biological age and scores on the Gross Motor Function Measure-88 and Bayley Scales of Infant Development III. Tri-iodothyronine concentrations were above the age-specific upper limit in 96 (95%) of 101 patients and free thyroxine concentrations were below the age-specific lower limit in 94 (89%) of 106 patients. 59 (71%) of 83 patients were underweight. 25 (53%) of 47 patients had elevated systolic blood pressure above the 90th percentile, 34 (76%) of 45 patients had premature atrial contractions, and 20 (31%) of 64 had resting tachycardia. The most consistent MRI finding was a global delay in myelination, which occurred in 13 (100%) of 13 patients.

Interpretation: Our description of characteristics of MCT8 deficiency in a large patient cohort reveals poor survival with a high prevalence of treatable underlying risk factors, and provides knowledge that might inform clinical management and future evaluation of therapies.

Funding: Netherlands Organisation for Health Research and Development, and the Sherman Foundation.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
July 2020

Functional Analyses of HNF1A-MODY Variants Refine the Interpretation of Identified Sequence Variants.

J Clin Endocrinol Metab 2020 04;105(4)

Department of Safety, Chemistry and Biomedical Laboratory Sciences, Western Norway University of Applied Sciences, Bergen, Norway.

Context: While rare variants of the hepatocyte nuclear factor-1 alpha (HNF1A) gene can cause maturity-onset diabetes of the young (HNF1A-MODY), other variants can be risk factors for the development of type 2 diabetes. As has been suggested by the American College of Medical Genetics (ACMG) guidelines for variant interpretation, functional studies provide strong evidence to classify a variant as pathogenic.

Objective: We hypothesized that a functional evaluation can improve the interpretation of the HNF1A variants in our Czech MODY Registry.

Design, Settings, And Participants: We studied 17 HNF1A variants that were identified in 48 individuals (33 female/15 male) from 20 Czech families with diabetes, using bioinformatics in silico tools and functional protein analyses (transactivation, protein expression, DNA binding, and nuclear localization).

Results: Of the 17 variants, 12 variants (p.Lys120Glu, p.Gln130Glu, p.Arg131Pro, p.Leu139Pro, p.Met154Ile, p.Gln170Ter, p.Glu187SerfsTer40, p.Phe215SerfsTer18, p.Gly253Arg, p.Leu383ArgfsTer3, p.Gly437Val, and p.Thr563HisfsTer85) exhibited significantly reduced transcriptional activity or DNA binding (< 40%) and were classified as (likely) pathogenic, 2/17 variants were (likely) benign and 3/17 remained of uncertain significance. Functional analyses allowed for the reclassification of 10/17 variants (59%). Diabetes treatment was improved in 20/29 (69%) carriers of (likely) pathogenic HNF1A variants.

Conclusion: Functional evaluation of the HNF1A variants is necessary to better predict the pathogenic effects and to improve the diagnostic interpretation and treatment, particularly in cases where the cosegregation or family history data are not available or where the phenotype is more diverse and overlaps with other types of diabetes.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
April 2020

Effectiveness and safety of the tri-iodothyronine analogue Triac in children and adults with MCT8 deficiency: an international, single-arm, open-label, phase 2 trial.

Lancet Diabetes Endocrinol 2019 09 31;7(9):695-706. Epub 2019 Jul 31.

Department of Paediatric Neurology, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.

Background: Deficiency of the thyroid hormone transporter monocarboxylate transporter 8 (MCT8) causes severe intellectual and motor disability and high serum tri-iodothyronine (T) concentrations (Allan-Herndon-Dudley syndrome). This chronic thyrotoxicosis leads to progressive deterioration in bodyweight, tachycardia, and muscle wasting, predisposing affected individuals to substantial morbidity and mortality. Treatment that safely alleviates peripheral thyrotoxicosis and reverses cerebral hypothyroidism is not yet available. We aimed to investigate the effects of treatment with the T analogue Triac (3,3',5-tri-iodothyroacetic acid, or tiratricol), in patients with MCT8 deficiency.

Methods: In this investigator-initiated, multicentre, open-label, single-arm, phase 2, pragmatic trial, we investigated the effectiveness and safety of oral Triac in male paediatric and adult patients with MCT8 deficiency in eight countries in Europe and one site in South Africa. Triac was administered in a predefined escalating dose schedule-after the initial dose of once-daily 350 μg Triac, the daily dose was increased progressively in 350 μg increments, with the goal of attaining serum total T concentrations within the target range of 1·4-2·5 nmol/L. We assessed changes in several clinical and biochemical signs of hyperthyroidism between baseline and 12 months of treatment. The prespecified primary endpoint was the change in serum T concentrations from baseline to month 12. The co-primary endpoints were changes in concentrations of serum thyroid-stimulating hormone (TSH), free and total thyroxine (T), and total reverse T from baseline to month 12. These analyses were done in patients who received at least one dose of Triac and had at least one post-baseline evaluation of serum throid function. This trial is registered with, number NCT02060474.

Findings: Between Oct 15, 2014, and June 1, 2017, we screened 50 patients, all of whom were eligible. Of these patients, four (8%) patients decided not to participate because of travel commitments. 46 (92%) patients were therefore enrolled in the trial to receive Triac (median age 7·1 years [range 0·8-66·8]). 45 (98%) participants received Triac and had at least one follow-up measurement of thyroid function and thus were included in the analyses of the primary endpoints. Of these 45 patients, five did not complete the trial (two patients withdrew [travel burden, severe pre-existing comorbidity], one was lost to follow-up, one developed of Graves disease, and one died of sepsis). Patients required a mean dose of 38.3 μg/kg of bodyweight (range 6·4-84·3) to attain T concentrations within the target range. Serum T concentration decreased from 4·97 nmol/L (SD 1·55) at baseline to 1·82 nmol/L (0·69) at month 12 (mean decrease 3·15 nmol/L, 95% CI 2·68-3·62; p<0·0001), while serum TSH concentrations decreased from 2·91 mU/L (SD 1·68) to 1·02 mU/L (1·14; mean decrease 1·89 mU/L, 1·39-2·39; p<0·0001) and serum free T concentrations decreased from 9·5 pmol/L (SD 2·5) to 3·4 (1·6; mean decrease 6·1 pmol/L (5·4-6·8; p<0·0001). Additionally, serum total T concentrations decreased by 31·6 nmol/L (28·0-35·2; p<0·0001) and reverse T by 0·08 nmol/L (0·05-0·10; p<0·0001). Seven treatment-related adverse events (transiently increased perspiration or irritability) occurred in six (13%) patients. 26 serious adverse events that were considered unrelated to treatment occurred in 18 (39%) patients (mostly hospital admissions because of infections). One patient died from pulmonary sepsis leading to multi-organ failure, which was unrelated to Triac treatment.

Interpretation: Key features of peripheral thyrotoxicosis were alleviated in paediatric and adult patients with MCT8 deficiency who were treated with Triac. Triac seems a reasonable treatment strategy to ameliorate the consequences of untreated peripheral thyrotoxicosis in patients with MCT8 deficiency.

Funding: Dutch Scientific Organization, Sherman Foundation, NeMO Foundation, Wellcome Trust, UK National Institute for Health Research Cambridge Biomedical Centre, Toulouse University Hospital, and Una Vita Rara ONLUS.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
September 2019

HIV Drug Efavirenz Inhibits CYP21A2 Activity with Possible Clinical Implications.

Horm Res Paediatr 2019 28;91(4):262-270. Epub 2019 Jun 28.

Division of Pediatric Endocrinology and Diabetology, Department of Pediatrics, Inselspital, University Hospital of Bern, University of Bern, Bern, Switzerland,

Background: The HIV drugs lopinavir and ritonavir have recently been reported to cause transient adrenal insufficiency in preterm newborns. We, therefore, considered HIV drugs as a cause of transiently elevated 17-hydroxyprogesterone (17OHP) levels in a neonatal screening test for congenital adrenal hyperplasia in a preterm girl exposed to zidovudine, efavirenz, tenofovir, and emtricitabine.

Objective: So far, HIV drugs have not been tested for their effect on steroidogenesis and the steroidogenic enzyme activity of CYP21A2 specifically in an in vitro system.

Methods: We tested the effect of efavirenz, tenofovir, emtricitabine, and zidovudine on steroidogenesis of human adrenal H295R cells. Cells were treated with the drugs at different concentrations including concentrations in therapeutic use. The effect on CYP21A2 activity was assessed by testing the conversion of radiolabeled 17OHP to 11-deoxycortisol. Cell viability was tested by an MTT assay. In addition, recombinant human CYP21A2 protein was used to assess direct drug effects on CYP21A2 activity.

Results: We observed significantly decreased CYP21A2 activity in both in vitro testing systems after treatment with efavirenz at therapeutic concentrations. Moreover, efavirenz affected cell viability. By contrast, the other test drugs did not affect steroidogenesis. Follow-up of our patient revealed elevated 17OHP and androgen levels during the first weeks of life, but values normalized spontaneously. Genetic testing for CYP21A2 mutations was negative. Thus, it remains unsettled whether the transient 17OHP elevation in this baby was due to a drug effect.

Conclusion: The HIV drug efavirenz inhibits CYP21A2 activity in vitro through direct interaction with enzyme catalysis at therapeutic concentrations. This may have clinical implications for HIV treatment in children and adults. However, so far, clinical data are scarce, and further studies are needed to be able to draw clinical conclusions.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
January 2020

CYP17A1 inhibitor abiraterone, an anti-prostate cancer drug, also inhibits the 21-hydroxylase activity of CYP21A2.

J Steroid Biochem Mol Biol 2017 11 8;174:192-200. Epub 2017 Sep 8.

Pediatric Endocrinology, Diabetology and Metabolism, University Children's Hospital, Inselspital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland. Electronic address:

Abiraterone is an inhibitor of CYP17A1 which is used for the treatment of castration resistant prostate cancer. Abiraterone is known to inhibit several drug metabolizing cytochrome P450 enzymes including CYP1A2, CYP2D6, CYP2C8, CYP2C9, CYP2C19, CYP3A4 and CYP3A5, but its effects on steroid metabolizing P450 enzymes are not clear. In preliminary results, we had observed inhibition of CYP21A2 by 1μM abiraterone. Here we are reporting the effect of abiraterone on activities of CYP21A2 in human adrenal cells as well as with purified recombinant CYP21A2. Cells were treated with varying concentrations of abiraterone for 24h and CYP21A2 activity was measured using [H] 17-hydroxyprogesterone as substrate. Whole steroid profile changes were determined by gas chromatography-mass spectrometry. Binding of abiraterone to purified CYP21A2 protein was measured spectroscopically. Computational docking was used to study the binding and interaction of abiraterone with CYP21A2. Abiraterone caused significant reduction in CYP21A2 activity in assays with cells and an inhibition of CYP21A2 activity was also observed in experiments using recombinant purified proteins. Abiraterone binds to CYP21A2 with an estimated Kd of 6.3μM. These inhibitory effects of abiraterone are at clinically used concentrations. A loss of CYP21A2 activity in combination with reduction of CYP17A1 activities by abiraterone could result in lower cortisol levels and may require monitoring for any potential adverse effects.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
November 2017

Androgen production in pediatric adrenocortical tumors may occur via both the classic and/or the alternative backdoor pathway.

Mol Cell Endocrinol 2017 09 10;452:64-73. Epub 2017 May 10.

Pediatric Endocrinology and Diabetology, Department of Pediatrics, Switzerland; Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Switzerland. Electronic address:

Children with adrenocortical tumors (ACTs) often present with virilization due to high tumoral androgen production, with dihydrotestosterone (DHT) as most potent androgen. Recent work revealed two pathways for DHT biosynthesis, the classic and the backdoor pathway. Usage of alternate routes for DHT production has been reported in castration-resistant prostate cancer, CAH and PCOS. To assess whether the backdoor pathway may contribute to the virilization of pediatric ACTs, we investigated seven children suffering from androgen producing tumors using steroid profiling and immunohistochemical expression studies. All cases produced large amounts of androgens of the classic and/or backdoor pathway. Variable expression of steroid enzymes was observed in carcinomas and adenomas. We found no discriminative pattern. This suggests that enhanced androgen production in pediatric ACTs is the result of deregulated steroidogenesis through multiple steroid pathways. Thus future treatments of ACTs targeting androgen overproduction should consider these novel steroid production pathways.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
September 2017

High Incidence of Heterozygous ABCC8 and HNF1A Mutations in Czech Patients With Congenital Hyperinsulinism.

J Clin Endocrinol Metab 2015 Dec 2;100(12):E1540-9. Epub 2015 Oct 2.

Department of Paediatrics, Second Faculty of Medicine (K.R., J.M., L.D., B.O., P.D., Z.S., J.L., S.P.), Charles University in Prague and University Hospital in Motol, Prague 150 06, Czech Republic; Genetics and Epigenetics in Health and Disease, Genetics and Genomic Medicine Programme (A.N., K.H.), Institute of Child Health, University College London, London WC1N 1EH, United Kingdom; KG Jebsen Center for Diabetes Research, Department of Clinical Science (L.B., I.A., L.A.N., P.R.N.), University of Bergen, Bergen N-5021, Norway; Department of Biomedicine (L.B.), University of Bergen, Bergen N-5021, Norway; Department of Paediatrics, First Faculty of Medicine (J.K.), Charles University in Prague and the General University Hospital in Prague, Prague 121 08, Czech Republic; Center for Medical Genetics and Molecular Medicine (I.A., L.A.N.), Haukeland University Hospital, Bergen N-5021, Norway; Center for Research of Diabetes, Metabolism and Nutrition and Second Department of Internal Medicine FNKV, Third Faculty of Medicine (B.R.), Charles University in Prague, Prague 100 00, Czech Republic; Department of Pediatrics (P.R.N.), Haukeland University Hospital, Bergen, N-5020 Norway; and Department of Paediatric Endocrinology (K.H.), Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, United Kingdom.

Context: Congenital hyperinsulinism of infancy (CHI) represents a group of heterogeneous disorders characterized by oversecretion of insulin from pancreatic β-cells causing severe hypoglycemia.

Objective: We studied the distribution of genetic causes of CHI in a Czech population.

Methods: Countrywide collection of patients with CHI included 40 subjects (12 females, median age of diagnosis, 1 wk [interquartile range, 1-612 wk]). We sequenced the ABCC8, KCNJ11, GLUD1, GCK, HADH, UCP2, SLC16A1, HNF4A, and HNF1A genes and investigated structural changes in the ABCC8 gene. We functionally tested novel variants in the ABCC8 gene by Rb(86+) efflux assay and novel variants in the HNF1A gene by transcriptional activation and DNA-binding tests.

Results: We found causal mutations in 20 subjects (50%): 19 carried a heterozygous mutation while one patient was homozygous for mutation in the ABCC8 gene. Specifically, we detected 11 mutations (seven novel) in ABCC8, one novel mutation in KCNJ11, five mutations (two novel) in HNF1A, two novel mutations in HNF4A, and one in GCK. We showed a decrease of activation by diazoxide in mutant KATP channels with novel ABCC8 variants by 41-91% (median, 82%) compared with wild-type (WT) channels and reduced transcriptional activity of mutant HNF1A proteins (2.9% for p.Asn62Lysfs93* and 22% for p.Leu254Gln) accompanied by no DNA-binding ability compared with WT HNF1A.

Conclusion: We detected a higher proportion of heterozygous mutations causing CHI compared with other cohorts probably due to lack of consanguinity and inclusion of milder CHI forms. Interestingly, HNF1A gene mutations represented the second most frequent genetic cause of CHI in the Czech Republic. Based on our results we present a genetic testing strategy specific for similar populations.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
December 2015

McCune Albright syndrome and bilateral adrenal hyperplasia: the GNAS mutation may only be present in adrenal tissue.

Hormones (Athens) 2015 Jul-Sep;14(3):447-50

Section on Endocrinology & Genetics, Program on Developmental Endocrinology & Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, USA.

Objective: Corticotropin (ACTH)-independent hypercortisolism due to bilateral adrenocortical hyperplasia (BAH) in infancy is an extremely rare condition that is often caused by McCune Albright syndrome (MAS). MAS is caused by an activating mutation of the GNAS gene which leads to increased cyclic (c) adenosine monophosphate (AMP) signaling. Most forms of BAH are linked to increased cAMP signaling. We report the case of an infant with MAS who had BAH.

Methods: Genomic DNA fragments from blood and adrenal tissue encompassing regions (exons 8 and 9) with the hot spot activating missense GNAS mutations were amplified by classical bidirectional Sanger sequencing.

Results: The infant was found to carry the most common GNAS mutation, in exon 8 (c.602G >A, p. R201H), only in her adrenocortical tissue, despite extensive skin and other findings.

Conclusions: We conclude that infants with MAS, despite absence of the GNAS activating mutation in blood, may still have significant clinical findings, including ACTH-independent hypercortisolism. Molecular confirmation of the diagnosis should be sought at the tissue level in these patients.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
May 2016

Genesis of two most prevalent PROP1 gene variants causing combined pituitary hormone deficiency in 21 populations.

Eur J Hum Genet 2016 Mar 10;24(3):415-20. Epub 2015 Jun 10.

Department of Pediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic.

Two variants (c.[301_302delAG];[301_302delAG] and c.[150delA];[150delA]) in the PROP1 gene are the most common genetic causes of recessively inherited combined pituitary hormones deficiency (CPHD). Our objective was to analyze in detail the origin of the two most prevalent variants. In the multicentric study were included 237 patients with CPHD and their 15 relatives carrying c.[301_302delAG];[301_302delAG] or c.[150delA];[150delA] or c.[301_302delAG];[ 150delA]. They originated from 21 different countries worldwide. We genotyped 21 single-nucleotide variant markers flanking the 9.6-Mb region around the PROP1 gene that are not in mutual linkage disequilibrium in the general populations--a finding of a common haplotype would be indicative of ancestral origin of the variant. Haplotypes were reconstructed by Phase and Haploview software, and the variant age was estimated using an allelic association method. We demonstrated the ancestral origin of both variants--c.[301_302delAG] was carried on 0.2 Mb-long haplotype in a majority of European patients arising ~101 generations ago (confidence interval 90.1-116.4). Patients from the Iberian Peninsula displayed a different haplotype, which was estimated to have emerged 23.3 (20.1-29.1) generations ago. Subsequently, the data indicated that both the haplotypes were transmitted to Latin American patients ~13.8 (12.2-17.0) and 16.4 (14.4-20.1) generations ago, respectively. The c.[150delA] variant that was carried on a haplotype spanning about 0.3 Mb was estimated to appear 43.7 (38.4-52.7) generations ago. We present strong evidence that the most frequent variants in the PROP1 gene are not a consequence of variant hot spots as previously assumed, but are founder variants.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
March 2016

Mast cell stabilization with sodium cromoglycate modulates pulmonary vessel wall remodeling during four-day hypoxia in rats.

Exp Lung Res 2015 Jun;41(5):283-92

1Department of Histology and Embryology, Second Faculty of Medicine, Charles University in Prague , Prague 5 - Motol , Czech Republic.

Aim Of The Study: In rats, the environment with low content of oxygen induces hypoxic pulmonary hypertension. Remodeling of pulmonary resistance arteries is particularly triggered by the mast cell degranulation products, e.g., rodent-like interstitial collagenase (matrix metalloproteinase 13). Administration of sodium cromoglycate leads to stabilization of mast cell granules, and thus to the modified remodeling process.

Materials And Methods: During four-day hypoxia, we treated rats with sodium cromoglycate. Pulmonary vascular remodeling was assessed as well as counts of periarterial pulmonary mast cells, both total and matrix metalloproteinase 13-positive ones.

Results: Four-day hypoxia induced remodeling of both resistance arteries and large conduit arteries. We have found increase in the tunica media thickness of resistance arteries. Tunica adventitia thickness of both resistance arteries and large conduit arteries with a diameter of over 300 μm increased as well; the latter ones revealed increase in the number of vasa vasorum in their walls. Mast cell stabilization suppressed hypoxic pulmonary vascular remodeling in resistance pulmonary arteries. Four-day hypoxia led to changes in distribution of toluidine blue-detected and MMP-13 positive periarterial mast cells; this redistribution was also influenced by the administration of sodium cromoglycate.

Conclusions: The number of pulmonary periarterial mast cells seemingly decreases during hypoxia due to their degranulation, which disables their identification. Large conduit arteries do not affect final blood pressure in the pulmonary vascular bed; however, their structure changes substantially under hypoxia. Such remodeling changes are not mediated by mast cell products only since they have occurred in spite of stabilization of mast cell granules.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
June 2015

Human NR5A1/SF-1 mutations show decreased activity on BDNF (brain-derived neurotrophic factor), an important regulator of energy balance: testing impact of novel SF-1 mutations beyond steroidogenesis.

PLoS One 2014 14;9(8):e104838. Epub 2014 Aug 14.

Pediatric Endocrinology, Department of Pediatrics and Department of Clinical Research, University Children's Hospital Bern, Bern, Switzerland.

Context: Human NR5A1/SF-1 mutations cause 46,XY disorder of sex development (DSD) with broad phenotypic variability, and rarely cause adrenal insufficiency although SF-1 is an important transcription factor for many genes involved in steroidogenesis. In addition, the Sf-1 knockout mouse develops obesity with age. Obesity might be mediated through Sf-1 regulating activity of brain-derived neurotrophic factor (BDNF), an important regulator of energy balance in the ventromedial hypothalamus.

Objective: To characterize novel SF-1 gene variants in 4 families, clinical, genetic and functional studies were performed with respect to steroidogenesis and energy balance.

Patients: 5 patients with 46,XY DSD were found to harbor NR5A1/SF-1 mutations including 2 novel variations. One patient harboring a novel mutation also suffered from adrenal insufficiency.

Methods: SF-1 mutations were studied in cell systems (HEK293, JEG3) for impact on transcription of genes involved in steroidogenesis (CYP11A1, CYP17A1, HSD3B2) and in energy balance (BDNF). BDNF regulation by SF-1 was studied by promoter assays (JEG3).

Results: Two novel NR5A1/SF-1 mutations (Glu7Stop, His408Profs*159) were confirmed. Glu7Stop is the 4th reported SF-1 mutation causing DSD and adrenal insufficiency. In vitro studies revealed that transcription of the BDNF gene is regulated by SF-1, and that mutant SF-1 decreased BDNF promoter activation (similar to steroid enzyme promoters). However, clinical data from 16 subjects carrying SF-1 mutations showed normal birth weight and BMI.

Conclusions: Glu7Stop and His408Profs*159 are novel SF-1 mutations identified in patients with 46,XY DSD and adrenal insufficiency (Glu7Stop). In vitro, SF-1 mutations affect not only steroidogenesis but also transcription of BDNF which is involved in energy balance. However, in contrast to mice, consequences on weight were not found in humans with SF-1 mutations.
View Article and Find Full Text PDF

Download full-text PDF

March 2016

Novel insight into etiology, diagnosis and management of primary adrenal insufficiency.

Horm Res Paediatr 2014 1;82(3):145-57. Epub 2014 Aug 1.

Department of Pediatrics, 2nd Faculty of Medicine, Charles University, Prague, Czech Republic.

Primary adrenal insufficiency (PAI) is a rare condition in childhood which is either inherited (mostly) or acquired. It is characterized by glucocorticoid and maybe mineralocorticoid deficiency. The most common form in children is 21-hydroxylase deficiency, which belongs to the steroid biosynthetic defects causing PAI. Newer forms of complex defects of steroid biosynthesis are P450 oxidoreductase deficiency and (apparent) cortisone reductase deficiency. Other forms of PAI include metabolic disorders, autoimmune disorders and adrenal dysgenesis, e.g. the IMAGe syndrome, for which the underlying genetic defect has been recently identified. Newer work has also expanded the genetic causes underlying isolated, familial glucocorticoid deficiency (FGD). Mild mutations of CYP11A1 or StAR have been identified in patients with FGD. MCM4 mutations were found in a variant of FGD in an Irish travelling community manifesting with PAI, short stature, microcephaly and recurrent infections. Finally, mutations in genes involved in the detoxification of reactive oxygen species were identified in patients with unsolved FGD. Most mutations were found in the enzyme nicotinamide nucleotide transhydrogenase, which uses the mitochondrial proton pump gradient to produce NADPH. NADPH is essential in maintaining high levels of reduced forms of antioxidant enzymes for the reduction of hydrogen peroxide. Similarly, mutations in the gene for TXNRD2 involved in this system were found in FGD patients, suggesting that the adrenal cortex is particularly susceptible to oxidative stress.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
May 2015

Genetic analysis of the CYP21A2 gene in neonatal dried blood spots from children with transiently elevated 17-hydroxyprogesterone.

Clin Endocrinol (Oxf) 2012 Aug;77(2):187-94

Department of Pediatrics, 2nd Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.

Background: Neonatal screening for congenital adrenal hyperplasia (CAH) identifies a certain proportion of newborns with transient moderate elevation of 17-hydroxyprogesterone (17-OHP). These children require regular follow-up until normalization of their 17-OHP levels. We investigated the possibility of reducing the individuals' recall rates by using genetic methods on their original neonatal dried blood spots.

Patients And Methods: We analysed neonatal dried blood spots from 753 subjects with transiently elevated levels of 17-OHP. The CYP21A2 gene was sequenced to detect point mutations, and the presence of CYP21A2 was further confirmed by two methods utilizing the difference between CYP21A2 and its CYP21A1P pseudogene in the sequence of exon 3 (8-bp deletion). The accuracy of the methods was verified using samples from 70 subjects with known CYP21A2 mutations and 181 healthy children.

Result: Among the 701 successfully sequenced samples from subjects with transiently elevated 17-OHP, 670 (95%) had no point mutations or novel variants in the CYP21A2 gene. We found no individuals carrying genotypes consistent with the diagnosis of CAH (i.e. homozygotes or compound heterozygotes for point mutations, large deletions or rearrangements). However, 21 heterozygous carriers of known point mutations that cause the classic and nonclassic forms of CAH were identified. Additionally, we detected eight heterozygous and two homozygous point variants with unknown functional significance.

Conclusion: Although CAH caused by 21-hydroxylase deficiency could be genetically excluded with a reasonable degree of confidence in 95% of the genotyped subjects that had transiently elevated 17-OHP, the performance of the tests was suboptimal when performed using dried blood spots and time-consuming in comparison with the current practice of repeated measurements of 17-OHP. The introduction of this method into clinical practice seems to be impractical at this stage.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
August 2012

Lessons learned from 5 years of newborn screening for congenital adrenal hyperplasia in the Czech Republic: 17-hydroxyprogesterone, genotypes, and screening performance.

Eur J Pediatr 2012 Jun 11;171(6):935-40. Epub 2012 Jan 11.

3rd Faculty of Medicine and University Hospital Kralovske Vinohrady, Department of Pediatrics, Charles University in Prague, Srobarova 50, 100 34, Prague 10, Czech Republic.

The aims were to summarize the experience and to determine the performance metrics of newborn screening (NBS) for congenital adrenal hyperplasia (CAH) in the Czech Republic. 17-Hydroxyprogesterone (17OHP) was measured in NBS samples prospectively in 545,026 newborns and retrospectively in 31 CAH patients born outside the study period. A total of 2,811 screened newborns had abnormal 17OHP; CAH was confirmed in 46 probands. One patient with a severe-moderate genotype of CAH had 17OHP below the cut-off and was diagnosed clinically. This corresponds to a screening sensitivity of 98% and a false positive rate (FPR) of 0.51%. The median of 17OHP in the most severe genotypes was 484 nmol/L (n = 21); in severe/moderate, 321 nmol/L (n = 30); in moderate, 61 nmol/L (n = 20); and in mild genotypes, 31 nmol/L (n = 7). NBS is efficient to detect severe CAH but may fail to detect milder variants. However, the FPR is too high but could be improved by application of a second tier test.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
June 2012

Anticancer and antiproliferative activity of natural brassinosteroids.

Phytochemistry 2008 Jan 14;69(2):418-26. Epub 2007 Sep 14.

Laboratory of Molecular Pathology, Institute of Pathology, Faculty of Medicine, Palacký University, Hnevotínská 3, 775 15 Olomouc, Czech Republic.

Brassinosteroids (BRs) are steroid plant hormones that are essential for many plant growth and developmental processes, including cell expansion, vascular differentiation and stress responses. Up to now the inhibitory effects of BRs on cell division of mammalian cells are unknown. To determine basic anticancer structure-activity relationships of natural BRs on human cells, several normal and cancer cell lines have been used. Several of the tested BRs were found to have high cytotoxic activity. Therefore, in our next series of experiments, we tested the effects of the most promising and readily available BR analogues with interesting anticancer properties, 28-homocastasterone (1) and 24-epibrassinolide (2), on the viability, proliferation, and cycling of hormone-sensitive/insensitive (MCF-7/MDA-MB-468) breast and (LNCaP/DU-145) prostate cancer cell lines to determine whether the discovered cytotoxic activity of BRs could be, at least partially, related to brassinosteroid-nuclear receptor interactions. Both BRs inhibited cell growth in a dose-dependent manner in the cancer cell lines. Flow cytometry analysis showed that BR treatment arrested MCF-7, MDA-MB-468 and LNCaP cells in G(1) phase of the cell cycle and induced apoptosis in MDA-MB-468, LNCaP, and slightly in the DU-145 cells. Our results provide the first evidence that natural BRs can inhibit the growth, at micromolar concentrations, of several human cancer cell lines without affecting the growth of normal cells. Therefore, these plant hormones are promising leads for potential anticancer drugs.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
January 2008

Effects of sanguinarine and chelerythrine on the cell cycle and apoptosis.

Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2006 Jul;150(1):5-12

Laboratory of Molecular Pathology and Institute of Pathology, Faculty of Medicine, Palacký University, Olomouc, Czech Republic.

Objectives: This review summarizes the involvement of sanguinarine and chelerythrine in cell cycle regulation and cell death in various cell lines. It is focused on their potential in the treatment of cancer.

Methods: We conducted a search of PubMed, ScienceDirect and Medline for papers on the molecular mechanisms of the biological activity of sanguinarine and chelerythrine published mainly from 1995 to 2006.

Results And Conclusions: Our analysis of the published studies suggested that these alkaloids are not only good candidates for chemotherapeutic regimens but may also contribute to the development of successful immune therapies of some carcinomas due to their apoptotic potential. However, the complete signalling cascade in which sanguinarine and chelerythrine treatment induces apoptotic cell death is not yet understood. Overall, the results of recent studies suggest that sanguinarine and chelerythrine may be useful as agents in the management of cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
July 2006