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1.
J Endocr Soc ; 5(9): bvab104, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34589658

RESUMO

Circulating plasma vitamin D metabolites are highly bound to vitamin D-binding protein (DBP), also known as group-specific component or Gc-globulin. DBP, encoded by the GC gene, is a member of the albumin family of globular serum transport proteins. We previously described a homozygous GC gene deletion in a patient with apparent severe vitamin D deficiency, fragility fractures, and ankylosing spondylitis. Here, we report an unrelated patient free of fractures or rheumatologic disease, but with very low 25-hydroxyvitamin D and 1,25-hydroxyvitamin D, as well as undetectable DBP measured by liquid chromatography-tandem mass spectrometry. A whole gene deletion was excluded by microarray, and Sanger sequencing of GC revealed a homozygous pathogenic variant affecting a canonical splice site (c0.702-1G > A). These findings indicate that loss of function variants in GC that eliminate DBP, and severely reduced total circulating vitamin D levels, do not necessarily result in significant metabolic bone disease. Together with our previous report, these cases support the free-hormone hypothesis, and suggest free vitamin D metabolites may serve as preferable indicators of bone and mineral metabolism, particularly when clinical suspicion of DBP deficiency is high.

2.
J Steroid Biochem Mol Biol ; 211: 105879, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33757895

RESUMO

Studies show an increase in circulating levels of 25-hydroxyvitamin D [25(OH)D] in women using combined oral contraceptives (COCs). 25(OH)D is a quantitatively important metabolite and widely used clinical marker of vitamin D status and is regulated by vitamin D binding protein (VDBP). However, studies have not identified the type of formulations used by the women, and there are no data on the effect of progestins on 25(OH)D levels. Our study objective was to compare the effects of two COC formulations [ethinyl estradiol (EE)/norethindrone acetate (NETA) vs. EE/levonorgestrel (LNG)] as well as LNG alone on total and bioavailable (free plus albumin-bound) 25(OH)D levels in serum samples collected at baseline, mid treatment, and end of treatment. Total 25(OH)D and VDBP were measured by immunoassay, and bioavailable 25(OH)D was calculated. The results show that with the EE/NETA formulation, total and bioavailable 25(OH)D and VDBP levels increased non-significantly by 7.4 %, 14.9 %, and 10 %, respectively, from baseline to end of treatment. In contrast, the corresponding changes with EE/LNG showed an increase of 4.4 % in total 25(OH)D but a significant decrease of 18.2 % in bioavailable 25(OH)D and increase of 19.1 % in VDBP. When LNG was administered alone, no significant changes were observed in total and bioavailable 25(OH)D or VDBP levels during the course of treatment. Our findings show considerably different effects on total and bioavailable 25(OH)D levels, as well as VDBP levels, with different oral contraceptive formulations. LNG may have a suppressive effect on VDBP, similar to its well-known androgenic effect on SHBG. Further studies are needed to determine the effect of hormonal contraceptive formulations on vitamin D status and its potential impact on women's health.


Assuntos
Anticoncepcionais Orais Combinados/administração & dosagem , Vitamina D/análogos & derivados , Adulto , Disponibilidade Biológica , Feminino , Humanos , Vitamina D/sangue
3.
PLoS One ; 15(2): e0228900, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053638

RESUMO

BACKGROUND: CMV infection of the fetus or neonate can lead to devastating disease, and there are no effective prevention strategies to date. Vitamin D is a potent immunomodulator, supports antiviral immune responses, and plays an important role in placental immunity. METHODS: Retrospective cohort study to evaluate the impact of low maternal vitamin D on congenital and early postnatal transmission of CMV among HIV-infected, non-breastfeeding women and their HIV exposed but negative infants from an urban HIV clinic. Vitamin D panel was performed on stored maternal plasma obtained near time of delivery. Infant CMV testing at 0-6 months included urine and oral cultures, and/or serum polymerase chain reaction testing. RESULTS: Cohort included 340 mother-infant pairs (births 1991-2014). Among 38 infants (11%) with a CMV+ test between 0-6 months, 4.7% (14/300) had congenital CMV transmission (CMV+ test 0-3 weeks), and 7.6% (24/315) had peri/postnatal CMV (CMV+ test >3 weeks-6 months). Women with lower calcitriol (1,25-dihydroxyvitamin D), the active form of vitamin D, were more likely to have an infant with congenital (OR 12.2 [95% CI 1.61-92.2] P = 0.02) and peri/postnatal (OR 9.84 [95% CI 2.63-36.8] P = 0.0007) infections in multivariate analyses, independent of maternal HIV viral load and CD4 count. CONCLUSION: This study demonstrates an association between inadequate maternal calcitriol during pregnancy and increased congenital and early postnatal acquisition of CMV among non-breastfeeding women with HIV and their HIV negative infants.


Assuntos
Infecções por Citomegalovirus/transmissão , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Deficiência de Vitamina D/metabolismo , Adulto , Antivirais/uso terapêutico , Contagem de Linfócito CD4 , Estudos de Coortes , Citomegalovirus/genética , Citomegalovirus/patogenicidade , Infecções por Citomegalovirus/imunologia , DNA Viral/sangue , Feminino , Infecções por HIV/complicações , Humanos , Lactente , Recém-Nascido , Plasma/virologia , Gravidez , Complicações Infecciosas na Gravidez/tratamento farmacológico , Estudos Retrospectivos , Carga Viral , Vitamina D/metabolismo , Deficiência de Vitamina D/fisiopatologia
4.
Am J Perinatol ; 37(14): 1446-1454, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-31365935

RESUMO

OBJECTIVE: To examine the association of vitamin D insufficiency and risk of pregnancy-induced hypertension (PIH) among human immunodeficiency virus (HIV)-infected pregnant women. STUDY DESIGN: This is a retrospective cohort study evaluating the impact of low maternal vitamin D levels on PIH and perinatal outcomes among HIV-infected pregnant women receiving care at an urban HIV center from 1991 to 2014. RESULTS: A total of 366 pregnant women were included, of which 11% developed PIH. Lower levels of 25-hydroxyvitamin D (25(OH)D) and bioactive 1,25-dihydroxyvitamin D (1,25(OH)2D) were associated with increased HIV disease activity. 25(OH)D levels were not significantly associated with the incidence of PIH. Higher 1,25(OH)2D levels were associated with reduced incidence of PIH in univariate (odds ratio, OR: 0.87 [95% confidence interval, CI: 0.79-0.95], p = 0.004) and multivariate (OR: 0.88 [95% CI: 0.80-0.97], p = 0.010) analyses. No association was found between 25(OH)D levels and other obstetric outcomes. Lower 1,25(OH)2D levels were associated with group B Streptococcus colonization (OR: 0.92 [95% CI: 0.86-0.99]) and low birth weight (LBW) (OR: 0.90 [95% CI: 0.83-0.98]) on multivariate analysis. Mean 1,25(OH)2D levels were significantly lower in women with preterm delivery and LBW infants. CONCLUSION: Lower bioactive vitamin D levels are related to PIH in HIV-infected women. This association may be related to the coexistence of abnormal placental vitamin D metabolism and abnormal placental implantation.


Assuntos
Infecções por HIV/epidemiologia , Hipertensão Induzida pela Gravidez/epidemiologia , Complicações na Gravidez/epidemiologia , Deficiência de Vitamina D/epidemiologia , Vitamina D/análogos & derivados , Adulto , California/epidemiologia , Feminino , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Modelos Logísticos , Masculino , Análise Multivariada , Gravidez , Nascimento Prematuro/epidemiologia , Estudos Retrospectivos , Vitamina D/sangue , Deficiência de Vitamina D/sangue , Adulto Jovem
5.
Reprod Biomed Online ; 38(2): 159-168, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30598377

RESUMO

RESEARCH QUESTION: Circulating soluble LH-HCG receptor (sLHCGR) is a first-trimester marker for screening pregnancy pathologies and predicts premature or multiple births before fertility treatment. Oestradiol per oocyte at ovulation induction predicts IVF treatment outcomes. We asked whether sLHCGR levels are stable during fertility treatment and whether, alone or with oestradiol, they could improve prediction of fertility treatment outcomes. DESIGN: Serum sLHCGR, anti-Müllerian hormone [AMH] and oestradiol were measured in patients undergoing IVF. Antral follicle count before ovarian stimulation and oocyte yield were used to establish sLHCGR- oocyte ratio (SOR), sLHCGR- antral follicle ratio (SAR), oestradiol at trigger per oocyte (oestradiol-oocyte ratio [EOR]) and oestradiol at trigger per antral follicle (oestradiol-antral follicle ratio [EAR]). RESULTS: The relatively stable sLHCGR was negatively related to AMH when oocyte yield was high. The sLHCGR levels were proportional (r = 0.49) to oestradiol at early cycle (day-3). Pregnancy and live birth were highest at low sLHCGR (≤1.0 pmol/ml) and SOR (≤ 0.1 pmol/ml/oocyte). A total of 86-89% of live births in IVF treatment were within the cut-off parameters of SAR and SOR (0.5 pmol/ml) and EAR and EOR (380 pg/ml). For failed pregnancy, age, SOR and EOR together had positive and negative predictive values of 0.841 and 0.703, respectively. CONCLUSIONS: sLHCGR levels are negatively related to AMH when oocyte yield is high. High early cycle sLHCGR is associated with elevated day-3 oestradiol. Low sLHCGR and SOR are indicators of increased clinical pregnancy and live birth rates. Patient age and SOR, combined with EOR, might improve prediction of IVF treatment outcomes.


Assuntos
Estradiol/sangue , Fertilização in vitro , Nascido Vivo , Taxa de Gravidez , Receptores do LH/sangue , Adulto , Hormônio Antimülleriano/sangue , Feminino , Humanos , Folículo Ovariano , Indução da Ovulação , Gravidez , Resultado da Gravidez
6.
Fertil Steril ; 101(2): 392-8, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24355054

RESUMO

OBJECTIVE: To determine whether serum hyperglycosylated human chorionic gonadotropin (hhCG) measured as early as 9 days after egg retrieval can predict ongoing pregnancies after in vitro fertilization and fresh embryo transfer (IVF-ET). DESIGN: Cohort SETTING: Academic assisted reproduction center. PATIENT(S): Consecutive patients undergoing IVF-ET INTERVENTION(S): Serum hhCG and hCG levels measured 9 (D9) and 16 (D16) days after egg retrieval MAIN OUTCOME MEASURE(S): Ongoing pregnancy beyond 9 weeks of gestation. RESULT(S): Ongoing pregnancy (62 of 112 participants) was associated with higher D9 levels of hhCG and hCG. However, hhCG was detectable in all D9 OP samples, while hCG was detectable in only 22%. A D9 hhCG level of >110 pg/mL was 96% specific for an ongoing pregnancy, yielding a positive predictive value of 94%. Compared with the D9 hCG levels, hhCG was more sensitive and had a larger area under the curve (0.87 vs. 0.67, respectively). The diagnostic test characteristics were similar between the D16 hhCG and hCG levels. CONCLUSION(S): In patients undergoing assisted reproduction, a test to detect pregnancy early and predict outcomes is highly desirable, and hhCG is detectable in serum 9 days after egg retrieval IVF-ET cycles. In this early assessment, hhCG was superior to traditional hCG and highly predictive of ongoing pregnancies.


Assuntos
Gonadotropina Coriônica/sangue , Fertilização in vitro/tendências , Resultado da Gravidez/epidemiologia , Adulto , Biomarcadores/sangue , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Glicosilação , Humanos , Projetos Piloto , Valor Preditivo dos Testes , Gravidez , Estudos Retrospectivos
7.
Development ; 140(19): 3965-76, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24004950

RESUMO

The placenta is a transient organ that is necessary for proper fetal development. Its main functional component is the trophoblast, which is derived from extra-embryonic ectoderm. Little is known about early trophoblast differentiation in the human embryo, owing to lack of a proper in vitro model system. Human embryonic stem cells (hESCs) differentiate into functional trophoblast following BMP4 treatment in the presence of feeder-conditioned media; however, this model has not been widely accepted, in part owing to a lack of proof for a trophoblast progenitor population. We have previously shown that p63, a member of the p53 family of nuclear proteins, is expressed in proliferative cytotrophoblast (CTB), precursors to terminally differentiated syncytiotrophoblast (STB) in chorionic villi and extravillous trophoblast (EVT) at the implantation site. Here, we show that BMP4-treated hESCs differentiate into bona fide CTB by direct comparison with primary human placental tissues and isolated CTB through gene expression profiling. We show that, in primary CTB, p63 levels are reduced as cells differentiate into STB, and that forced expression of p63 maintains cyclin B1 and inhibits STB differentiation. We also establish that, similar to in vivo events, hESC differentiation into trophoblast is characterized by a p63(+)/KRT7(+) CTB stem cell state, followed by formation of functional KLF4(+) STB and HLA-G(+) EVT. Finally, we illustrate that downregulation of p63 by shRNA inhibits differentiation of hESCs into functional trophoblast. Taken together, our results establish that BMP4-treated hESCs are an excellent model of human trophoblast differentiation, closely mimicking the in vivo progression from p63(+) CTB stem cells to terminally differentiated trophoblast subtypes.


Assuntos
Proteína Morfogenética Óssea 4/farmacologia , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/efeitos dos fármacos , Trofoblastos/citologia , Trofoblastos/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Feminino , Citometria de Fluxo , Perfilação da Expressão Gênica , Idade Gestacional , Humanos , Técnicas In Vitro , Fator 4 Semelhante a Kruppel , Placenta/citologia , Gravidez , Reação em Cadeia da Polimerase em Tempo Real
8.
J Assist Reprod Genet ; 29(7): 609-14, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22527905

RESUMO

OBJECTIVE: To determine the sensitivity and specificity of hyperglycosylated hCG (hhCG) measurements for the diagnosis of clinical pregnancies in the IVF setting and how soon post embryo transfer (ET) a pregnancy can be detected using an ultrasensitive (hhCG) assay. To determine if a single, early hhCG measurement can discriminate between biochemical and clinical pregnancies. DESIGN: A 4 center prospective blinded clinical trial was performed with patients undergoing IVF-ET. Patients had blood drawn and submitted for hhCG analysis on the day of ET and at days 4, 6, 8, and 12 thereafter. First morning urines were collected and submitted for hhCG analysis on days 0, 4, 6, 8, 10 and 12. SETTING: Fertility Centers OUTCOME MEASURES: Clinical pregnancies were defined as an ultrasound study demonstrating a gestational sac and/or heart beat at appropriate gestational ages. RESULTS: Fifty-six of 58 enrolled patients completed the study. There were 25 clinical and 6 biochemical pregnancies. For blastocyst transfers, a single serum or urine hhCG measurement identified pregnancies (both biochemical and clinical) at 6 days post ET with 100% sensitivity and specificity. There were 6 biochemical pregnancies, all following blastocyst transfers. All of these pregnancies were identified by lower values.


Assuntos
Gonadotropina Coriônica/sangue , Fertilização in vitro , Testes de Gravidez/métodos , Adulto , Transferência Embrionária , Feminino , Glicosilação , Humanos , Gravidez , Taxa de Gravidez , Estudos Prospectivos , Sensibilidade e Especificidade , Adulto Jovem
10.
Clin Chem ; 51(8): 1499-504, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15961547

RESUMO

BACKGROUND: In the United States, Down syndrome screening is still performed mainly in the second trimester, using 3 or 4 markers. Moving screening into the first trimester has the advantage of earlier diagnosis. Currently, first-trimester screening typically includes maternal serum pregnancy-associated plasma protein-A (PAPP-A), the free beta-subunit of human chorionic gonadotropin (free beta), and ultrasound measurement of nuchal translucency thickness (NT). The current report describes a case-control study of serum invasive trophoblast antigen (ITA) and its possible inclusion in first-trimester screening for Down syndrome. METHODS: As part of an earlier observational study, serum samples from 54 Down syndrome and 276 matched unaffected pregnancies were collected between 9 and 15 weeks of gestation. Samples had been aliquoted and stored at -20 degrees C for 8 years. ITA was measured and converted to weight-adjusted multiples of the median (MoM). The distributions of other first-trimester markers are from a single published study. RESULTS: Median ITA MoM in Down syndrome pregnancies increase as gestational age increases (2.02 MoM at 11 and 2.44 MoM at 13 completed weeks). At 75% detection, maternal age in combination with ITA and PAPP-A measurements have an 8.0% false-positive rate, slightly lower than the 8.8% found for the free beta and PAPP-A combination; adding NT measurements reduces false positives for the 2 combinations to 2.0% and 1.8%, respectively. CONCLUSION: Serum ITA appears to be a useful first-trimester Down syndrome marker that could replace free beta measurements while maintaining performance.


Assuntos
Gonadotropina Coriônica/sangue , Síndrome de Down/diagnóstico , Trofoblastos/metabolismo , Autoanálise , Biomarcadores/sangue , Estudos de Casos e Controles , Reações Falso-Positivas , Feminino , Glicosilação , Humanos , Imunoensaio , Medições Luminescentes , Programas de Rastreamento/métodos , Gravidez , Primeiro Trimestre da Gravidez , Proteína Plasmática A Associada à Gravidez/análise
11.
Clin Chem ; 50(10): 1804-8, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15319323

RESUMO

BACKGROUND: Approximately two million pregnancies in the United States are screened for Down syndrome annually by use of second-trimester maternal serum markers. At present, a combination of four markers can identify 75% of affected pregnancies when 5% of screened women are classified as candidates for amniocentesis. Although not currently included in screening panels, invasive trophoblast antigen (ITA) is a promising screening marker in serum or urine in both the second and first trimesters. This study aims at better defining the screening performance of serum ITA in the second trimester. METHODS: In an earlier study, serum samples from an unbiased sampling of 45 Down syndrome (cases) and 238 unaffected (control) pregnancies between 14 and 20 weeks of gestation were collected from various centers in the United States. Samples were aliquoted and stored at -20 degrees C for 8 years. We measured ITA in these samples and determined the screening performance both univariately and in combination with other screening markers. RESULTS: The median ITA in Down syndrome pregnancies was >3.00 multiples of the median, higher than that found for human chorionic gonadotropin (hCG) or free beta-hCG. At a 5% false-positive rate, ITA univariately detected 38% and 40% of Down syndrome pregnancies, respectively, when assigned by date of last menstrual period or ultrasound date. Modeling yielded rates of 45% and 48%. ITA correlated strongly with hCG and free beta-hCG. When substituted for either of these in a multiple marker panel, ITA performed comparably. CONCLUSIONS: This study indicates that serum ITA is an effective marker for Down syndrome. It is highly correlated with both hCG and free beta-hCG and could replace either of them in a multiple marker panel.


Assuntos
Gonadotropina Coriônica/sangue , Síndrome de Down/diagnóstico , Programas de Rastreamento/métodos , Biomarcadores/sangue , Síndrome de Down/sangue , Reações Falso-Positivas , Feminino , Humanos , Gravidez , Segundo Trimestre da Gravidez , Soro
12.
BMC Dermatol ; 4: 4, 2004 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-15119959

RESUMO

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) and its receptors play important roles in the development and persistence of psoriatic plaques. The antithyroid thioureylenes, propylthiouracil and methimazole, are effective in the treatment of patients with psoriasis with a significant number of patients showing clearing or near clearing of their lesions after a several weeks of treatment. METHODS: The present study examined the effect of treatment with propylthiouracil, given in a dose of 100 mg every 8 hours for 3 months, on the serum levels of TNF-alpha in 9 patients with plaque psoriasis. RESULTS: Propylthiouracil therapy did not result in a significant decline in serum TNF-alpha concentrations. CONCLUSIONS: The findings suggest that the therapeutic effect of propylthiouracil in psoriasis appears not to be related to any change in the concentration of TNF-alpha but occurs via an anti-proliferative mechanism as we have previously speculated.


Assuntos
Antitireóideos/uso terapêutico , Propiltiouracila/uso terapêutico , Psoríase/tratamento farmacológico , Fator de Necrose Tumoral alfa/análise , Adulto , Idoso , Antimetabólitos/farmacologia , Antimetabólitos/uso terapêutico , Antitireóideos/farmacologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Propiltiouracila/farmacologia , Psoríase/sangue
14.
Clin Lab Med ; 24(1): 141-74, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15157561

RESUMO

No laboratory test has sufficient diagnostic sensitivity and specificity to serve as a gold standard for the diagnosis for GHD: therefore, test results must be interpreted after assessment of risk for GHD is determined on clinical grounds. Growth data are particularly crucial for diagnosis of childhood GHD;history of known pituitary damage and presence or absence of other pituitary hormone deficiencies are the critical elements for the diagnosis of adult GHD. New reference preparations are available for GH and IGF-I and should greatly aid interassay comparisons when the preparations are universally adopted.GH stimulation testing remains a key part of the diagnosis of adult GHD, but is currently being de-emphasized for the diagnosis of pediatric GHD. Better interassay comparative data and organized clinical collaboration between clinicians and test manufacturers/laboratories to set rational clinical diagnostic cutoffs would improve greatly the clinical usefulness of GH stimulation testing. The availability of statistically sound age- and sex-related normative data for IGF-I and IGFBP3 make these key tests for the diagnosis of childhood GHD. Although IGF-I may not be a perfect test for the diagnosis of adult GHD, it may be sufficiently informative in many cases to warrant using it ona routine basis. IGF-I also has a role in monitoring the safety of adult patients who are on GH treatment; studies are underway to determine if IGF-I may be useful in the future for optimization of GH dosaging.


Assuntos
Química Clínica/métodos , Nanismo Hipofisário/diagnóstico , Hormônio do Crescimento Humano/deficiência , Doenças da Hipófise/diagnóstico , Adulto , Química Clínica/normas , Criança , Humanos
15.
Clin Chem ; 50(1): 182-9, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14709646

RESUMO

BACKGROUND: Down syndrome screening is commonly performed in the US using maternal age and three or four second-trimester maternal serum markers that can identify up to 75% of affected pregnancies by offering diagnostic studies to 5% of women. Invasive trophoblast antigen [ITA; hyperglycosylated human chorionic gonadotropin (hCG)] is a promising marker that can be measured in urine or serum in the first or second trimester. We report preliminary results for urinary ITA in an ongoing observational study. METHODS: Women undergoing second-trimester amniocentesis for reasons not associated with biochemical testing provided consent and a urine (and possibly serum) sample that was tested within a few days. Demographic and pregnancy-related information was collected, along with karyotype. Screening performance was modeled for ITA alone and in combination with serum markers RESULTS: Twelve recruitment centers collected urine from 2055 women with singleton pregnancies between 15 and 20 weeks of gestation (2023 unaffected, 28 Down syndrome, and 4 pregnancies with other chromosome abnormalities). After correction for gestational age, urine concentration, and maternal race and weight, the ITA measurements were higher in women with a Down syndrome pregnancy (median ITA, 4.33 multiples of the median). At a 75% detection rate, the false-positive rate could be reduced by substituting ITA for hCG measurements (from 5.6% to 2.6% for the triple test) or by adding ITA measurements to existing combinations (from 3.3% to 2.0% for the quadruple test). CONCLUSIONS: Our data provide preliminary confirmation of the potential usefulness of urinary ITA measurements in detecting Down syndrome in a setting that simulates routine usage.


Assuntos
Gonadotropina Coriônica/urina , Síndrome de Down/diagnóstico , Trofoblastos/metabolismo , Adulto , Biomarcadores/urina , Gonadotropina Coriônica/metabolismo , Reações Falso-Positivas , Feminino , Humanos , Idade Materna , Gravidez , Segundo Trimestre da Gravidez , Gravidez de Alto Risco
17.
Hypertension ; 39(1): 135-41, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11799092

RESUMO

Chronic renal failure (CRF) is associated with oxidative stress which promotes production of reactive carbonyl compounds and lipoperoxides leading to the accumulation of advanced glycation and lipoxidation end products. Reactive oxygen species (ROS) avidly reacts with nitric oxide (NO) producing cytotoxic reactive nitrogen species capable of nitrating proteins and damaging other molecules. This study tested the hypothesis that CRF results in enhanced ROS-mediated NO inactivation and protein nitration which can be ameliorated with antioxidant therapy. Male Sprague Dawley rats were randomized to CRF (5/6 nephrectomy) and sham-operated controls and fed either a regular diet (vitamin E, 40 U/Kg food) or an antioxidant-fortified diet (vitamin E, 5000 U/Kg food) for 6 weeks. Blood pressure, plasma malondialdehyde (MDA), tissue NO synthase (NOS) isoforms, tissue nitrotyrosine (the footprint of NO interaction with ROS), and vascular tissue NO production were determined. CRF resulted in marked elevations of blood pressure, plasma MDA, and tissue nitrotyrosine abundance, but did not change plasma L-arginine level. This was coupled with depressed vascular tissue NO production and reduced immunodetectable NOS proteins in the vascular, renal, and cardiac tissues. Antioxidant therapy ameliorated the CRF-induced hypertension, improved vascular tissue NO production, lowered tissue nitrotyrosine burden, and reversed downregulations of NOS isoforms. In contrast, antioxidant therapy had no effects in the controls. CRF is associated with oxidative stress which promotes NO inactivation by ROS leading to functional NO deficiency, hypertension, and widespread accumulation of protein nitration products. Amelioration of oxidative stress by high-dose vitamin E enhances NO availability, improves hypertension, lowers protein nitration products, and increases NOS expression and vascular NO production in CRF animals.


Assuntos
Falência Renal Crônica/metabolismo , Nitratos/metabolismo , Óxido Nítrico/antagonistas & inibidores , Proteínas/metabolismo , Tirosina/análogos & derivados , Animais , Antioxidantes/farmacologia , Arginina/sangue , Creatinina/urina , Endotélio Vascular/enzimologia , Endotélio Vascular/metabolismo , Falência Renal Crônica/sangue , Falência Renal Crônica/enzimologia , Masculino , Músculo Liso Vascular/enzimologia , Músculo Liso Vascular/metabolismo , Óxido Nítrico/biossíntese , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo II , Óxido Nítrico Sintase Tipo III , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Tirosina/sangue , Tirosina/metabolismo , alfa-Tocoferol/sangue , alfa-Tocoferol/farmacologia
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