Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
1.
Trials ; 23(1): 35, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-35033182

RESUMEN

BACKGROUND: Since December 2019, SARS-CoV-2 virus has infected millions of people worldwide. In patients with COVID-19 pneumonia in need of oxygen therapy or mechanical ventilation, dexamethasone 6 mg per day is currently recommended. However, the dose of 6 mg of dexamethasone is currently being reappraised and may miss important therapeutic potential or may prevent potential deleterious effects of higher doses of corticosteroids. METHODS: REMED is a prospective, open-label, randomised controlled trial testing the superiority of dexamethasone 20 mg (dexamethasone 20 mg on days 1-5, followed by dexamethasone 10 mg on days 6-10) vs 6 mg administered once daily intravenously for 10 days in adult patients with moderate or severe ARDS due to confirmed COVID-19. Three hundred participants will be enrolled and followed up for 360 days after randomization. Patients will be randomised in a 1:1 ratio into one of the two treatment arms. The following stratification factors will be applied: age, Charlson Comorbidity Index, CRP levels and trial centre. The primary endpoint is the number of ventilator-free days (VFDs) at 28 days after randomisation. The secondary endpoints are mortality from any cause at 60 days after randomisation; dynamics of the inflammatory marker, change in WHO Clinical Progression Scale at day 14; and adverse events related to corticosteroids and independence at 90 days after randomisation assessed by the Barthel Index. The long-term outcomes of this study are to assess long-term consequences on mortality and quality of life at 180 and 360 days. The study will be conducted in the intensive care units (ICUs) of ten university hospitals in the Czech Republic. DISCUSSION: We aim to compare two different doses of dexamethasone in patients with moderate to severe ARDS undergoing mechanical ventilation regarding efficacy and safety. TRIAL REGISTRATION: EudraCT No. 2020-005887-70. ClinicalTrials.gov NCT04663555. Registered on December 11, 2020.


Asunto(s)
Tratamiento Farmacológico de COVID-19 , Síndrome de Dificultad Respiratoria , Adulto , Dexametasona/efectos adversos , Humanos , Estudios Multicéntricos como Asunto , Estudios Prospectivos , Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto , Síndrome de Dificultad Respiratoria/diagnóstico , Síndrome de Dificultad Respiratoria/tratamiento farmacológico , SARS-CoV-2 , Resultado del Tratamiento
2.
Trials ; 22(1): 172, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33648568

RESUMEN

OBJECTIVES: The primary objective of this study is to test the hypothesis that administration of dexamethasone 20 mg is superior to a 6 mg dose in adult patients with moderate or severe ARDS due to confirmed COVID-19. The secondary objective is to investigate the efficacy and safety of dexamethasone 20 mg versus dexamethasone 6 mg. The exploratory objective of this study is to assess long-term consequences on mortality and quality of life at 180 and 360 days. TRIAL DESIGN: REMED is a prospective, phase II, open-label, randomised controlled trial testing superiority of dexamethasone 20 mg vs 6 mg. The trial aims to be pragmatic, i.e. designed to evaluate the effectiveness of the intervention in conditions that are close to real-life routine clinical practice. PARTICIPANTS: The study is multi-centre and will be conducted in the intensive care units (ICUs) of ten university hospitals in the Czech Republic. INCLUSION CRITERIA: Subjects will be eligible for the trial if they meet all of the following criteria: 1. Adult (≥18 years of age) at time of enrolment; 2. Present COVID-19 (infection confirmed by RT-PCR or antigen testing); 3. Intubation/mechanical ventilation or ongoing high-flow nasal cannula (HFNC) oxygen therapy; 4. Moderate or severe ARDS according to Berlin criteria: • Moderate - PaO2/FiO2 100-200 mmHg; • Severe - PaO2/FiO2 < 100 mmHg; 5. Admission to ICU in the last 24 hours. EXCLUSION CRITERIA: Subjects will not be eligible for the trial if they meet any of the following criteria: 1. Known allergy/hypersensitivity to dexamethasone or excipients of the investigational medicinal product (e.g. parabens, benzyl alcohol); 2. Fulfilled criteria for ARDS for ≥14 days at enrolment; 3. Pregnancy or breastfeeding; 4. Unwillingness to comply with contraception measurements from enrolment until at least 1 week after the last dose of dexamethasone (sexual abstinence is considered an adequate contraception method); 5. End-of-life decision or patient is expected to die within next 24 hours; 6. Decision not to intubate or ceilings of care in place; 7. Immunosuppression and/or immunosuppressive drugs in medical history: a) Systemic immunosuppressive drugs or chemotherapy in the past 30 days; b) Systemic corticosteroid use before hospitalization; c) Any dose of dexamethasone during the present hospital stay for COVID-19 for ≥5 days before enrolment; d) Systemic corticosteroids during present hospital stay for conditions other than COVID-19 (e.g. septic shock); 8. Current haematological or generalized solid malignancy; 9. Any contraindication for corticosteroid administration, e.g. • intractable hyperglycaemia; • active gastrointestinal bleeding; • adrenal gland disorders; • presence of superinfection diagnosed with locally established clinical and laboratory criteria without adequate antimicrobial treatment; 10. Cardiac arrest before ICU admission; 11. Participation in another interventional trial in the last 30 days. INTERVENTION AND COMPARATOR: Dexamethasone solution for injection/infusion is the investigational medicinal product as well as the comparator. The trial will assess two doses, 20 mg (investigational) vs 6 mg (comparator). Patients in the intervention group will receive dexamethasone 20 mg intravenously once daily on day 1-5, followed by dexamethasone 10 mg intravenously once daily on day 6-10. Patients in the control group will receive dexamethasone 6 mg day 1-10. All authorized medicinal products containing dexamethasone in the form of solution for i.v. injection/infusion can be used. MAIN OUTCOMES: Primary endpoint: Number of ventilator-free days (VFDs) at 28 days after randomisation, defined as being alive and free from mechanical ventilation. SECONDARY ENDPOINTS: a) Mortality from any cause at 60 days after randomisation; b) Dynamics of inflammatory marker (C-Reactive Protein, CRP) change from Day 1 to Day 14; c) WHO Clinical Progression Scale at Day 14; d) Adverse events related to corticosteroids (new infections, new thrombotic complications) until Day 28 or hospital discharge; e) Independence at 90 days after randomisation assessed by Barthel Index. The long-term outcomes of this study are to assess long-term consequences on mortality and quality of life at 180 and 360 days through telephone structured interviews using the Barthel Index. RANDOMISATION: Randomisation will be carried out within the electronic case report form (eCRF) by the stratified permuted block randomisation method. Allocation sequences will be prepared by a statistician independent of the study team. Allocation to the treatment arm of an individual patient will not be available to the investigators before completion of the whole randomisation process. The following stratification factors will be applied: • Age <65 and ≥ 65; • Charlson Comorbidity index (CCI) <3 and ≥3; • CRP <150 mg/L and ≥150 mg/L • Trial centre. Patients will be randomised in a 1 : 1 ratio into one of the two treatment arms. Randomisation through the eCRF will be available 24 hours every day. BLINDING (MASKING): This is an open-label trial in which the participants and the study staff will be aware of the allocated intervention. Blinded pre-planned statistical analysis will be performed. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): The sample size is calculated to detect the difference of 3 VFDs at 28 days (primary efficacy endpoint) between the two treatment arms with a two-sided type I error of 0.05 and power of 80%. Based on data from a multi-centre randomised controlled trial in COVID-19 ARDS patients in Brazil and a multi-centre observational study from French and Belgian ICUs regarding moderate to severe ARDS related to COVID-19, investigators assumed a standard deviation of VFD at 28 days as 9. Using these assumptions, a total of 142 patients per treatment arm would be needed. After adjustment for a drop-out rate, 150 per treatment arm (300 patients per study) will be enrolled. TRIAL STATUS: This is protocol version 1.1, 15.01.2021. The trial is due to start on 2 February 2021 and recruitment is expected to be completed by December 2021. TRIAL REGISTRATION: The study protocol was registered on EudraCT No.:2020-005887-70, and on December 11, 2020 on ClinicalTrials.gov (Title: Effect of Two Different Doses of Dexamethasone in Patients With ARDS and COVID-19 (REMED)) Identifier: NCT04663555 with a last update posted on February 1, 2021. FULL PROTOCOL: The full protocol (version 1.1) is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest of expediting dissemination of this material, the standard formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.


Asunto(s)
COVID-19/terapia , Dexametasona/administración & dosificación , Glucocorticoides/administración & dosificación , Respiración Artificial , Síndrome de Dificultad Respiratoria/terapia , COVID-19/complicaciones , Ensayos Clínicos Fase II como Asunto , Progresión de la Enfermedad , Relación Dosis-Respuesta a Droga , Estudios de Equivalencia como Asunto , Humanos , Tiempo de Internación , Estudios Multicéntricos como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto , Síndrome de Dificultad Respiratoria/etiología , SARS-CoV-2
3.
J Steroid Biochem Mol Biol ; 155(Pt B): 217-23, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24816231

RESUMEN

This introductory chapter provides an overview of the levels and sites at which endocrine disruptors (EDs) affect steroid actions. In contrast to the special issue of Journal of Steroid Biochemistry and Molecular Biology published three years ago and devoted to EDs as such, this paper focuses on steroids. We tried to point to more recent findings and opened questions. EDs interfere with steroid biosynthesis and metabolism either as inhibitors of relevant enzymes, or at the level of their expression. Particular attention was paid to enzymes metabolizing steroid hormones to biologically active products in target cells, such as aromatase, 5α-reductase and 3ß-, 11ß- and 17ß-hydroxysteroid dehydrogenases. An important target for EDs is also steroid acute regulatory protein (StAR), responsible for steroid precursor trafficking to mitochondria. EDs influence receptor-mediated steroid actions at both genomic and non-genomic levels. The remarkable differences in response to various steroid-receptor ligands led to a more detailed investigation of events following steroid/disruptor binding to the receptors and to the mapping of the signaling cascades and nuclear factors involved. A virtual screening of a large array of EDs with steroid receptors, known as in silico methods (≡computer simulation), is another promising approach for studying quantitative structure activity relationships and docking. New data may be expected on the effect of EDs on steroid hormone binding to selective plasma transport proteins, namely transcortin and sex hormone-binding globulin. Little information is available so far on the effects of EDs on the major hypothalamo-pituitary-adrenal/gonadal axes, of which the kisspeptin/GPR54 system is of particular importance. Kisspeptins act as stimulators for hormone-induced gonadotropin secretion and their expression is regulated by sex steroids via a feed-back mechanism. Kisspeptin is now believed to be one of the key factors triggering puberty in mammals, and various EDs affect its expression and function. Finally, advances in analytics of EDs, especially those persisting in the environment, in various body fluids (plasma, urine, seminal fluid, and follicular fluid) are mentioned. Surprisingly, relatively scarce information is available on the simultaneous determination of EDs and steroids in the same biological material. This article is part of a Special Issue entitled 'Endocrine disruptors & steroids'.


Asunto(s)
Disruptores Endocrinos/farmacología , Hormonas Esteroides Gonadales/metabolismo , Sistema Hipotálamo-Hipofisario/efectos de los fármacos , Sistema Hipófiso-Suprarrenal/efectos de los fármacos , 17-Hidroxiesteroide Deshidrogenasas/genética , 17-Hidroxiesteroide Deshidrogenasas/metabolismo , 3-Oxo-5-alfa-Esteroide 4-Deshidrogenasa/genética , 3-Oxo-5-alfa-Esteroide 4-Deshidrogenasa/metabolismo , Disruptores Endocrinos/historia , Regulación de la Expresión Génica , Hormonas Esteroides Gonadales/historia , Ensayos Analíticos de Alto Rendimiento , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Sistema Hipotálamo-Hipofisario/metabolismo , Simulación del Acoplamiento Molecular , Sistema Hipófiso-Suprarrenal/metabolismo , Receptores de Esteroides/genética , Receptores de Esteroides/metabolismo , Globulina de Unión a Hormona Sexual/genética , Globulina de Unión a Hormona Sexual/metabolismo , Transducción de Señal , Relación Estructura-Actividad , Transcortina/genética , Transcortina/metabolismo
4.
BMC Anesthesiol ; 15: 38, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25821405

RESUMEN

BACKGROUND: Remifentanil has been suggested for its short duration of action to replace standard opioids for induction of general anaesthesia in caesarean section. While the stabilizing effect of remifentanil on maternal circulation has been confirmed, its effect on postnatal adaptation remains unclear, as currently published studies are not powered sufficiently to detect any clinical effect of remifentanil on the newborn. METHODS: Using a double-blinded randomized design, a total of 151 parturients undergoing caesarean delivery under general anaesthesia were randomized into two groups--76 patients received a bolus of remifentanil prior to induction, while 75 patients were assigned to the control group. Remifentanil 1 µg/kg was administered 30 seconds before the standard induction of general anaesthesia. The primary outcome measure was an assessment of neonatal adaptation using the Apgar score, while secondary outcomes included the need for respiratory support after delivery and differences in umbilical blood gas analysis (Astrup). RESULTS: The incidence of lower Apgar scores between 0 and 7 was significantly higher in the remifentanil group at one minute (25% vs. 9.3% of newborns, p = 0.017); whilst at five minutes and later no Apgar score differences were observed. There was no difference in the need for moderate (nasal CPAP) or intensive (intubation) respiratory support, but significantly more neonates in the remifentanil group required tactile stimulation for breathing support (21% vs. 7% of newborns, p = 0.017). There was no difference in the parameters from umbilical cord blood gas analysis between the groups. CONCLUSION: At a dose of 1 µg/kg, remifentanil prior to induction of general anaesthesia increases the risk of neonatal respiratory depression during first minutes after caesarean delivery but duration of clinical symptoms is short. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01550640.


Asunto(s)
Analgésicos Opioides/efectos adversos , Anestésicos Generales/efectos adversos , Cesárea , Piperidinas/efectos adversos , Trastornos Respiratorios/inducido químicamente , Adaptación Fisiológica/efectos de los fármacos , Adolescente , Adulto , Anestesia General/efectos adversos , Puntaje de Apgar , Método Doble Ciego , Femenino , Humanos , Recién Nacido , Persona de Mediana Edad , Embarazo , Resultado del Embarazo , Estudios Prospectivos , Remifentanilo , Respiración Artificial , Adulto Joven
5.
J Steroid Biochem Mol Biol ; 139: 201-22, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23583279

RESUMEN

In this review we focused on steroid metabolomics in human fetuses and newborns and its role in the physiology and pathophysiology of human pregnancy and subsequent stages of human life, and on the physiological relevance of steroids influencing the nervous systems with regards to their concentrations in the fetus. Steroid profiling provides valuable data for the diagnostics of diseases related to altered steroidogenesis in the fetal and maternal compartments and placenta. We outlined a potential use of steroid metabolomics for the prediction of reproductive disorders, misbalance of hypothalamic-pituitary-adrenal axis, and impaired insulin sensitivity in subsequent stages of human life. A possible role of steroids exhibiting a non-genomic effect in the development of gestational diabetes and in the neuroprotection via negative modulation of AMPA/kainate receptors was also indicated. Increasing progesterone synthesis and catabolism, declining production of tocolytic 5ß-pregnane steroids, and rising activities of steroid sulfotransferases with the approaching term may be of importance in sustaining pregnancy. An increasing trend was demonstrated with advancing gestation toward the production of ketones (and 3ß-hydroxyl groups in the case of 3α-hydroxy-steroids) was demonstrated in the fetus on the expense of 3α-hydroxy-, 17ß-hydroxy-, and 20α-hydroxy-groups weakening in the sequence C17, C3, and C20. There was higher production of active progestogen but lower production of active estrogen and GABAergic steroids with the approaching term. Rising activities of placental CYP19A1 and oxidative isoforms of HSD17B, and of fetal CYP3A7 with advancing gestation may protect the fetus from hyperestrogenization. This article is part of a Special Issue entitled 'Pregnancy and Steroids'.


Asunto(s)
Encéfalo/metabolismo , Feto/metabolismo , Hormonas Esteroides Gonadales/fisiología , Corticoesteroides/fisiología , Animales , Estrógenos/fisiología , Femenino , Desarrollo Fetal , Humanos , Embarazo , Progestinas/fisiología
6.
Horm Mol Biol Clin Investig ; 13(1): 1-5, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25436708

RESUMEN

The data on hormonal steroids in the human seminal plasma and their role in spermatogenesis are summarized. The seminal steroid levels need not correlate with the blood plasma levels. The recent reports showed that androgen, especially dihydrotestosterone, and the estrogen levels in the seminal fluid may be used as the markers of spermatogenesis impairment. The estradiol concentration in the seminal plasma was higher than in the blood plasma, and its levels were significantly increased in men with impaired spermatogenesis. A good indicator for predicting the normal spermatogenesis, therefore, seems to be the testosterone/estradiol ratio. The seminal plasma also contains significant amounts of cortisol, which influences the androgen biosynthesis through its receptors in the Leydig cells. The local balance between cortisol and inactive cortisone is regulated by 11ß-hydroxysteroid dehydrogenase, the activity of which may be affected by the environmental chemicals acting as the endocrine disruptors (EDCs). These compounds are believed to participate in worsening the semen quality - the sperm count, motility, and morphology, as witnessed in the recent last decades. As to the steroids' role in the testis, the EDCs may act as antiandrogens by inhibiting the enzymes of testosterone biosynthesis, as the agonists or antagonists through their interaction with the steroid hormone receptors, or at the hypothalamic-pituitary-gonadal axis. Surprisingly, though the EDCs affect the steroid action in the testis, there is no report of a direct association between the concentrations of steroids and the EDCs in the seminal fluid. Therefore, measuring the steroids in the semen, along with the various EDCs, could help us better understand the role of the EDCs in the male reproduction.


Asunto(s)
Disruptores Endocrinos/metabolismo , Semen/citología , Semen/metabolismo , Espermatogénesis , Esteroides/metabolismo , Animales , Humanos , Masculino , Reproducción , Semen/química , Esteroides/análisis
7.
Steroids ; 76(12): 1351-7, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21787799

RESUMEN

BACKGROUND: Epilepsy in women may be associated with reproductive disorders and alterations in serum steroid levels. Some steroids can be induced by epilepsy and/or treatment with antiepileptic drugs; however, there are still limited data available concerning this effect on the levels of other neuroactive steroid metabolites such as 3a-hydroxy-5a/b-reduced androstanes. AIM: To evaluate steroid alterations in women with epilepsy (WWE) on lamotrigine monotherapy. SUBJECTS AND METHODS: Eleven WWE and 11 age-matched healthy women underwent blood sampling in both phases of their menstrual cycles (MCs). The steroid metabolome, which included 30 unconjugated steroids, 17 steroid polar conjugates, gonadotropins, and sex hormone-binding globulin (SHBG), was measured using gas chromatography-mass spectrometry (GC-MS) and radioimmunoassay (RIA). RESULTS: WWE had lower cortisol levels (status p<0.001), but elevated levels of unconjugated 17-hydroxypregnenolone (status p<0.001). Progesterone was higher in the follicular menstrual phase (FP) in WWE than in the controls (status×menstrual phase p<0.05, Bonferroni multiple comparisons p<0.05), whereas 17-hydroxyprogesterone was higher in WWE in both menstrual phases (status p<0.001). The steroid conjugates were mostly elevated in WWE. The levels of 5α/ß-reduced androstanes in WWE that were significantly higher than the controls were etiocholanolone (status p<0.001), 5α-androstane-3α,17ß-diol (status p<0.001), and the 5α/ß-reduced androstane polar conjugates (status p<0.001). CONCLUSIONS: WWE showed a trend toward higher circulating 3α-hydroxy-5α/ß-reduced androstanes, increased activity of 17α-hydroxylase/17,20 lyase in the Δ(5)-steroid metabolic pathway, and increased levels of the steroid polar conjugates.


Asunto(s)
17-alfa-Hidroxipregnenolona/sangre , Androstanos/sangre , Androstanos/metabolismo , Anticonvulsivantes/uso terapéutico , Epilepsia/tratamiento farmacológico , Epilepsia/metabolismo , Triazinas/uso terapéutico , Adulto , Androstanoles/sangre , Anticonvulsivantes/efectos adversos , Femenino , Humanos , Lamotrigina , Metaboloma , Esteroide 17-alfa-Hidroxilasa/sangre , Triazinas/efectos adversos
8.
Horm Mol Biol Clin Investig ; 6(3): 259-64, 2011 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-25961264

RESUMEN

BACKGROUND: Smoking represents the most widespread substance dependence in the world. Several studies show nicotine's ability to alter women hormonal homeostasis. Women smokers have higher testosterone and lower estradiol levels throughout life compared to women non-smokers. This negatively affects women's reproductive function. Furthermore, alteration of neuroactive and neuroprotective steroids occurs in women smokers, and this plays an important role in the activity of the central nervous system, cognition, mental condition, and degree of substance dependence. METHODS: We monitored the effect of smoking discontinuation on steroid spectrum in 40 premenopausal women heavy smokers. These women were examined before they began to discontinue smoking, and after 6, 12, 24 and 48 weeks of abstinence. In each examination, blood was collected to determine steroid spectrum, LH, FSH, and SHBG; basic anthropometric data were also measured using GC-MS or immunoanalysis. Repeated-measures analysis of variance (ANOVA) model was used for evaluation of the data. RESULTS: Given the small number of women who persisted in not smoking, only the data after 6 weeks could be analyzed. No changes were found in C21 steroids, and a slight increase in androgens occurred after the discontinuation of smoking. CONCLUSION: Chronic smoking causes hyperandrogenism in fertile women; after smoking discontinuation, it increases further. Longer-term monitoring is necessary to show the effect of smoking discontinuation on steroid spectrum.

9.
J Steroid Biochem Mol Biol ; 122(4): 239-52, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20541012

RESUMEN

Only limited data is available concerning the role of unconjugated Δ(5) C19-steroids and almost no data exists regarding the neuroactive C21 and C19 3α-hydroxy-5α/ß-metabolites in men with epilepsy. To evaluate the alterations in serum neuroactive steroids and related substances in adult men with epilepsy on valproate and carbamazepine monotherapy, we have measured 26 unconjugated steroids, 18 steroid polar conjugates, gonadotropins and sex hormone binding globulin (SHBG) in 6 and 11 patients on valproate and carbamazepine monotherapy, respectively, and in 19 healthy adult men, using the GC-MS and immunoassays. Decreased testosterone, free androgen index, free testosterone, androstenediol, 5α-androstane-3α,17ß-diol (androstanediol), androsterone, epiandrosterone, DHEA, 7ß-hydroxy-DHEA, and DHEAS levels were associated with epilepsy per se. Valproate (VPA) therapy increased 5α-dihydrotestosterone, androsterone, epiandrosterone, DHEA, DHEAS, and 7ß-hydroxy-DHEA levels. Decrease in pregnenolone and 17-hydroxypregnenolone were associated with epilepsy with no effect of antiepileptic drugs (AEDs). Alternatively, the increase in progesterone levels was linked to epilepsy and VPA further increased progesterone levels. Reduced steroid 20α-hydroxy-metabolites and cortisol were connected with epilepsy without an effect of AEDs. Carbamazepine induced only slight decrease in isopregnanolone, 5α,20α-tetrahydroprogesterone, and androstanediol levels.


Asunto(s)
Anticonvulsivantes/uso terapéutico , Carbamazepina/uso terapéutico , Epilepsia/tratamiento farmacológico , Esteroides/sangre , Ácido Valproico/uso terapéutico , Adulto , Androstanos/sangre , Cromatografía de Gases y Espectrometría de Masas , Gonadotropinas/sangre , Humanos , Masculino , Pregnenolona/sangre , Globulina de Unión a Hormona Sexual/metabolismo , Esteroides/metabolismo , Testosterona/análogos & derivados , Testosterona/sangre
10.
J Steroid Biochem Mol Biol ; 122(4): 114-32, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20580824

RESUMEN

Despite the extensive research during the last six decades the fundamental questions concerning the role of steroids in the initiation of human parturition and origin and function of some steroids in pregnancy were not definitely answered. Based on steroid metabolomic data found in the literature and our so far unpublished results, we attempted to bring new insights concerning the role of steroids in the sustaining and termination of human pregnancy, and predictive value of these substances for estimation of term. We also aimed to explain enigmas concerning the biosynthesis of progesterone and its bioactive catabolites considering the conjunctions between placental production of CRH, synthesis of bioactive steroids produced by fetal adrenal, localization of placental oxidoreductases and sustaining of human pregnancy. Evaluation of data available in the literature, including our recent findings as well as our new unpublished data indicates increasing progesterone synthesis and its concurrently increasing catabolism with approaching parturition, confirms declining production of pregnancy sustaining 5ß-pregnane steroids providing uterine quiescence in late pregnancy, increased sulfation of further neuroinhibiting and pregnancy sustaining steroids. In contrast to the established concept considering LDL cholesterol as the primary substrate for progesterone synthesis in pregnancy, our data demonstrates the functioning of alternative mechanism for progesterone synthesis, which is based on the utilization of fetal pregnenolone sulfate for progesterone production in placenta. Close relationships were found between localization of placental oxidoreductases and consistently higher levels of sex hormones, neuroactive steroids and their metabolites in the oxidized form in the fetus and in the reduced form in the maternal compartment.


Asunto(s)
Feto/metabolismo , Placenta/metabolismo , Embarazo/metabolismo , Esteroides/metabolismo , Femenino , Humanos
11.
Horm Mol Biol Clin Investig ; 4(3): 581-600, 2010 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-25961235

RESUMEN

Using information based on the steroid metabolome in maternal and fetal body fluids, we attempted to ascertain whether there is a common mechanism, which is based on the placental distribution of various isoforms of 17ß-hydroxysteroid dehydrogenases and aldo-keto reductases. This system simultaneously provides a higher proportion of active progestogens in fetal circulation and a higher proportion of active estrogens and GABAergic steroids in the maternal compartment. The data obtained using gas chromatography-mass spectrometry completely support the aforementioned hypothesis. We confirmed a common trend to higher ratios of steroids with hydroxy-groups in the 3α-, 17ß-, and 20α-positions to the corresponding 3-oxo-, 17-oxo-, and 20-oxo-metabolites, respectively, in the maternal blood when compared with the fetal circulation, and the same tendency was obvious in the 3α-hydroxy/3ß-hydroxy steroid ratios. A decreasing trend was observed in the ratios of active estrogens and neuro-inhibitory steroids to their inactive counterparts in fetal and maternal body fluids. This was probably associated with a limited capacity of placental oxidoreductases in the converting of estrone to estradiol during the transplacental passage. Although we observed a decreasing trend in pregnancy-sustaining steroids with increasing gestational age, we recorded rising levels of estradiol and particularly of estriol, regardless of the limited capacity of placental oxidoreductases. Besides the estradiol, which is generally known as an active estrogen, estriol may be of importance for the termination of pregnancy with respect to its excessive concentrations near term which allows its binding to estrogen receptors.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...