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1.
Nord J Psychiatry ; 78(3): 165-180, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38270399

RESUMO

BACKGROUND: Online self-harming and suicidal behavior is a novel and rapidly increasing phenomenon warranting comprehensive mapping of used research methods. AIM: To identify and map how knowledge on online self-harming and suicidal behavior is gathered, including how data are collected e.g. questionnaires and interviews. METHODS: The review follows the Joanna Briggs Institute Manual for Scoping Reviews in tandem with Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. A keyword search of three electronic databases was conducted on two occasions, yielding 5422 records. Following duplicate removal, the records were screened based on the following inclusion criterions; (1) in English or Nordic language and published between 2011-2022, (2) presenting results for self-harming and/or suicidal behavior on social media and (3) using tools for either interview or questionnaire aiming at assessment of the experience of online self-harming and suicidal behavior from the perspective of the person who engages in the behavior. A total of 64 articles were included. RESULTS: 45 used questionnaires, 17 used interviews, and two studies mixed the two approaches. 17% of the studies had made some effort to ensure validity within the questionnaires and 15.8% gave full access to the interview guide. CONCLUSION: Research into online self-harming and suicidal behavior is characterized by a lack of validated measurements and methodological transparency. The results emphasize a need for further development, testing, and validation of questionnaires and greater openness and reflexivity in qualitative methodology to enable cross-study comparison and advance knowledge of this complex phenomenon.


Assuntos
Comportamento Autodestrutivo , Humanos , Comportamento Autodestrutivo/psicologia , Internet , Ideação Suicida , Inquéritos e Questionários , Tentativa de Suicídio/psicologia , Projetos de Pesquisa
2.
PLoS Genet ; 14(10): e1007667, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30289878

RESUMO

The role of host genetic variation in the development of complicated Staphylococcus aureus bacteremia (SAB) is poorly understood. We used whole exome sequencing (WES) to examine the cumulative effect of coding variants in each gene on risk of complicated SAB in a discovery sample of 168 SAB cases (84 complicated and 84 uncomplicated, frequency matched by age, sex, and bacterial clonal complex [CC]), and then evaluated the most significantly associated genes in a replication sample of 240 SAB cases (122 complicated and 118 uncomplicated, frequency matched for age, sex, and CC) using targeted sequence capture. In the discovery sample, gene-based analysis using the SKAT-O program identified 334 genes associated with complicated SAB at p<3.5 x 10-3. These, along with eight biologically relevant candidate genes were examined in the replication sample. Gene-based analysis of the 342 genes in the replication sample using SKAT-O identified one gene, GLS2, significantly associated with complicated SAB (p = 1.2 x 10-4) after Bonferroni correction. In Firth-bias corrected logistic regression analysis of individual variants, the strongest association across all 10,931 variants in the replication sample was with rs2657878 in GLS2 (p = 5 x 10-4). This variant is strongly correlated with a missense variant (rs2657879, p = 4.4 x 10-3) in which the minor allele (associated here with complicated SAB) has been previously associated with lower plasma concentration of glutamine. In a microarray-based gene-expression analysis, individuals with SAB exhibited significantly lower expression levels of GLS2 than healthy controls. Similarly, Gls2 expression is lower in response to S. aureus exposure in mouse RAW 264.7 macrophage cells. Compared to wild-type cells, RAW 264.7 cells with Gls2 silenced by CRISPR-Cas9 genome editing have decreased IL1-ß transcription and increased nitric oxide production after S. aureus exposure. GLS2 is an interesting candidate gene for complicated SAB due to its role in regulating glutamine metabolism, a key factor in leukocyte activation.


Assuntos
Glutaminase/genética , Infecções Estafilocócicas/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Animais , Bacteriemia , Feminino , Frequência do Gene/genética , Variação Genética/genética , Glutaminase/metabolismo , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Células RAW 264.7 , Fatores de Risco , Staphylococcus aureus/patogenicidade , Transcriptoma/genética , Sequenciamento do Exoma/métodos
3.
Basic Res Cardiol ; 112(3): 30, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28409279

RESUMO

Vascular remodelling in hypoxia-induced pulmonary hypertension (PH) is driven by excessive proliferation and migration of endothelial and smooth muscle cells. The expression of aquaporin 1 (AQP1), an integral membrane water channel protein involved in the control of these processes, is tightly regulated by oxygen levels. The role of AQP1 in the pathogenesis of PH, however, has not been directly addressed so far. This study was designed to characterize expression and function of AQP1 in pulmonary vascular cells from human arteries and in the mouse model of hypoxia-induced PH. Exposure of human pulmonary vascular cells to hypoxia significantly induced the expression of AQP1. Similarly, levels of AQP1 were found to be upregulated in lungs of mice with hypoxia-induced PH. The functional role of AQP1 was further tested in human pulmonary artery smooth muscle cells demonstrating that depletion of AQP1 reduced proliferation, the migratory potential, and, conversely, increased apoptosis of these cells. This effect was associated with higher expression of the tumour suppressor gene p53. Using the mouse model of hypoxia-induced PH, application of GapmeR inhibitors targeting AQP1 abated the hypoxia-induced upregulation of AQP1 and, of note, reversed PH by decreasing both right ventricular pressure and hypertrophy back to the levels of control mice. Our data suggest an important functional role of AQP1 in the pathobiology of hypoxia-induced PH. These results offer novel insights in our pathogenetic understanding of the disease and propose AQP1 as potential therapeutic in vivo target.


Assuntos
Aquaporina 1/metabolismo , Hipertensão Pulmonar/metabolismo , Miócitos de Músculo Liso/metabolismo , Remodelação Vascular/fisiologia , Animais , Western Blotting , Células Cultivadas , Modelos Animais de Doenças , Humanos , Hipóxia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Músculo Liso Vascular/metabolismo , Fenótipo , Artéria Pulmonar/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
4.
Eur Heart J ; 35(45): 3203-11, 2014 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-22450430

RESUMO

AIMS: Dysregulation of the bone morphogenetic protein receptor type 2 (BMPR2) is a hallmark feature that has been described in several forms of pulmonary hypertension. We recently identified the microRNA miR-20a within a highly conserved pathway as a regulator of the expression of BMPR2. To address the pathophysiological relevance of this pathway in vivo, we employed antagomiR-20a and investigated whether specific inhibition of miR-20a could restore functional levels of BMPR2 and, in turn, might prevent pulmonary arterial vascular remodelling. METHODS AND RESULTS: For specific inhibition of miR-20a, cholesterol-modified RNA oligonucleotides (antagomiR-20a) were synthesized. The experiments in mice were performed by using the hypoxia-induced mouse model for pulmonary hypertension and animal tissues were analysed for right ventricular hypertrophy and pulmonary arterial vascular remodelling. Treatment with antagomiR-20a enhanced the expression levels of BMPR2 in lung tissues; moreover, antagomiR-20a significantly reduced wall thickness and luminal occlusion of small pulmonary arteries and reduced right ventricular hypertrophy. To assess BMPR2 signalling and proliferation, we performed in vitro experiments with human pulmonary arterial smooth muscle cells (HPASMCs). Transfection of HPASMCs with antagomiR-20a resulted in activation of downstream targets of BMPR2 showing increased activation of Id-1 and Id-2. Proliferation of HPASMCs was found to be reduced upon transfection with antagomiR-20a. CONCLUSION: This is the first report showing that miR-20a can be specifically targeted in an in vivo model for pulmonary hypertension. Our data emphasize that treatment with antagomiR-20a restores functional levels of BMPR2 in pulmonary arteries and prevents the development of vascular remodelling.


Assuntos
Anti-Hipertensivos/farmacologia , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/fisiologia , Hipertensão Pulmonar/prevenção & controle , Hipóxia/complicações , MicroRNAs/antagonistas & inibidores , Remodelação Vascular/efeitos dos fármacos , Animais , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/metabolismo , Proliferação de Células/fisiologia , Colesterol/análogos & derivados , Colesterol/farmacologia , Circulação Coronária/fisiologia , Modelos Animais de Doenças , Hipertensão Pulmonar/etiologia , Hipertrofia Ventricular Direita/fisiopatologia , Técnicas In Vitro , Masculino , Camundongos , Músculo Liso Vascular/citologia , Oligorribonucleotídeos/farmacologia , Circulação Pulmonar/fisiologia , Transdução de Sinais/fisiologia , Transfecção
5.
Am J Physiol Lung Cell Mol Physiol ; 304(4): L230-9, 2013 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-23204066

RESUMO

Endothelial cell dysfunction is a common event to several pathologies including pulmonary hypertension, which is often associated with hypoxia. As the endothelium plays an essential role in regulating the dynamic interaction between pulmonary vasodilatation and vasoconstriction, this cell type is fundamental in the development of vascular remodeling and increased vascular resistance. We investigated the protective effects of sildenafil, a phosphodiesterase type 5 inhibitor, given in combination with erythropoietin (Epo), as it has been demonstrated that both drugs have antiapoptotic effects on several cell types. Specifically, we examined the viability and angiogenic properties of rat pulmonary artery endothelial cells upon exposure to either 21% or 1% oxygen, in presence of sildenafil (1 and 100 nM) and Epo (5 and 20 U/ml) alone or in combination (1 nM and 20 U/ml). Cell proliferation and viability were analyzed by Trypan blue staining, MTT assay, and Annexin V/propidium iodide stainings. In all assays, the ability of the combination treatment in improving cell viability was superior to that of either drug alone. The angiogenic properties were studied using a migration and a 3D collagen assay, and the results revealed increases in the migration potential of endothelial cells as well as the ability to form tube-like structures in response to sildenafil and the combination treatment. We therefore conclude that both drugs exert protective effects on endothelial cells on hypoxia and that sildenafil enhances the migratory and angiogenic properties, especially in hypoxic conditions. Furthermore, we present evidence of possible additive or synergistic effects of both drugs.


Assuntos
Hipóxia Celular/fisiologia , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Eritropoetina/farmacologia , Piperazinas/farmacologia , Sulfonas/farmacologia , Animais , Apoptose/efeitos dos fármacos , Hipóxia Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sinergismo Farmacológico , Endotélio Vascular/citologia , Epoetina alfa , Eritropoetina/administração & dosagem , Fosforilação/efeitos dos fármacos , Piperazinas/administração & dosagem , Purinas/administração & dosagem , Purinas/farmacologia , Ratos , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/farmacologia , Citrato de Sildenafila , Sulfonas/administração & dosagem
6.
BJUI Compass ; 4(5): 513-522, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37636207

RESUMO

Background: Prostate-specific membrane antigen (PSMA)-positron emission tomography/contrast-enhanced computed tomography (PET/CT) is a sensitive imaging modality for prostate cancer (PCa). Due to lack of knowledge of the patient benefit, PSMA-PET/CT is not yet recommended in the European guidelines for staging and treatment planning of patients with newly diagnosed PCa. We will investigate the potential difference in progression-free survival (PFS) and quality of life (QoL) of using PSMA-PET/CT versus sodium fluoride (NaF)-PET/CT for staging and treatment planning in patients with newly diagnosed PCa. Study Design: This is a prospective randomised controlled multicentre trial carried out at three centres in the Region of Southern Denmark. Endpoints: The primary endpoint is PFS. Secondary endpoints are residual disease, stage migration, impact on treatment strategies, stage distribution, QoL and diagnostic accuracy measures. Patients and Methods: Patients eligible for the study have newly diagnosed unfavourable intermediate- or high-risk PCa. A total of 448 patients will be randomised 1:1 into two groups: (A) a control group staged with Na[18F]F-PET/CT and (B) an intervention group staged with [18F]PSMA-1007-PET/CT. A subgroup in the intervention group will have a supplementary blinded Na[18F]F-PET/CT performed for the purpose of performing accuracy analyses. QoL will be assessed at baseline and with regular intervals (3-12 months) during the study period. Treatment decisions are achieved at multidisciplinary team conferences based on the results of the respective scans and according to current Danish guidelines. Trial Registration: The Regional Committees on Health Research Ethics for Southern Denmark (S-20190161) and the Danish Medicines Agency (EudraCT Number 2021-000123-12) approved the study, and it has been registered on clinicaltrials.gov (Record 2020110469).

7.
BMC Public Health ; 12: 590, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22852799

RESUMO

BACKGROUND: Research shows that obesity prevention has to start early. Targeting interventions towards subgroups of individuals who are predisposed, but yet normal weight, may prove more effective in preventing overweight than interventions towards unselected normal weight subsets. Finally, interventions focused on other factors than diet and activity are lacking. The objectives were to perform a randomized, controlled intervention aiming at preventing overweight in children aged 2-6 years, who are yet normal weight, but have high predisposition for future overweight, and to intervene not only by improving diet and physical activity, but also reduce stress and improve sleep quality and quantity. METHODS/DESIGN: Based on information from the Danish National Birth Registry and administrative birth forms, children were selected based on having either a high birth weight, a mother who was overweight prior to pregnancy, or a familial low socioeconomic status. Selected children (n = 5,902) were randomized into three groups; an intervention group, a shadow control group followed in registers exclusively, and a control group examined at the beginning and at the end of the intervention. Approximately 21% agreed to participate. Children who presented as overweight prior to the intervention were excluded from this study (n = 92). In the intervention group, 271 children were included, and in the control group 272 were included. Information obtained from the shadow control group is on-going, but it is estimated that 394 children will be included. The intervention took place over on average 1½ year between 2009 and 2011, and consisted of optional individual guidance in optimizing diet and physical activity habits, reducing chronic stress and stressful events and improving sleep quality and quantity. The intervention also included participation in cooking classes and play arrangements. Information on dietary intake, meal habits, physical activity, sleep habits, and overall stress level was obtained by 4-7 day questionnaire diaries and objective measurements. DISCUSSION: If the Healthy Start project is effective in preventing excessive weight gain, it will provide valuable information on new determinants of obesity which should be considered in future interventions, and on new strategies to prevent development of overweight and obesity at an early age.


Assuntos
Promoção da Saúde/métodos , Sobrepeso/prevenção & controle , Criança , Pré-Escolar , Dinamarca/epidemiologia , Dieta , Feminino , Previsões , Humanos , Masculino , Atividade Motora , Sobrepeso/epidemiologia , Medição de Risco , Fatores de Risco , Sono , Estresse Psicológico/prevenção & controle
8.
Res Rep Urol ; 14: 33-38, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35178362

RESUMO

PURPOSE: Serum levels of the polypeptide chemokine C-C motif ligand 2 (CCL2) have previously shown potential as a prostate cancer diagnostic and prognostic biomarker. Plasma CCL2 levels may be superior to serum levels as a biomarker because of their potentially lower signal-to-noise ratio. MATERIALS AND METHODS: Before initiating a large comparative study of plasma and serum CCL2 levels, we performed a prospective, diagnostic pilot study Of 133 individuals from a clinically relevant population. CCL2 plasma levels were measured using a validated assay kit. Plasma was obtained independently of digital rectal examination. RESULTS: In this pilot study, we found no relationship between CCL2 plasma values and risk of proven prostate cancer, whereas previous studies found a strong diagnostic relationship between CCL2 serum values and prostate cancer. CONCLUSION: Our contribution to the existing literature strengthens the idea that early in the pathological process, CCL2 mainly circulates in large, membrane-enclosed compartments, whereas plasma CCL2 levels increase markedly during disease progression. We conclude that whereas plasma CCL2 levels are not useful as a diagnostic measure, a ratio of CCL2 plasma to serum levels may prove useful as a marker of disease progression, which warrants further study.

9.
Proteomics ; 11(23): 4492-502, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21905223

RESUMO

The present study was designed to analyze protein expression in lungs from pulmonary hypertensive rats in order to identify novel signaling pathways. This was achieved by proteomic studies in which proteins from lung homogenates from hypoxic were compared to normoxic rats. The expression of these proteins was then investigated in lungs from hypoxic rats treated with either an activator of soluble guanylyl cyclase, BAY 412272, or an inhibitor of phosphodiesterase type 5, sildenafil. The proteomic study revealed an up-regulation of guanine nucleotide-binding protein ß, GST-ω-1, cathepsin D, chloride intracellular channel subunit 5, annexin A4, F-actin capping protein CapZ (CapZα), and the translation factor elongation factor 1 δ in lungs from chronic hypoxic rats with pulmonary hypertension. Immunohistochemistry revealed that CapZα, cathepsin D, and annexin A4 were expressed in the pulmonary vascular wall and immunoblotting showed these proteins correlated to alterations in muscularization. Both drugs inhibited hypoxia-induced increase in right ventricular systolic pressure and pulmonary arterial muscularization, and prevented most of the protein regulations observed after hypoxia. These findings suggest that pulmonary pressure is an important factor for initiating signaling pathways leading to protein expression and muscularization in the pulmonary vasculature.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Hipertensão Pulmonar/genética , Pulmão/efeitos dos fármacos , Pulmão/fisiopatologia , Proteoma/análise , Proteoma/genética , Sequência de Aminoácidos , Animais , Guanilato Ciclase/metabolismo , Hemodinâmica , Hipertensão Pulmonar/metabolismo , Hipertensão Pulmonar/fisiopatologia , Hipóxia/genética , Hipóxia/metabolismo , Pulmão/irrigação sanguínea , Pulmão/metabolismo , Masculino , Dados de Sequência Molecular , Inibidores da Fosfodiesterase 5/farmacologia , Piperazinas/farmacologia , Proteoma/metabolismo , Proteômica , Purinas/farmacologia , Pirazóis/farmacologia , Piridinas/farmacologia , Ratos , Ratos Wistar , Transdução de Sinais , Citrato de Sildenafila , Sulfonas/farmacologia
10.
Proteomics ; 9(19): 4457-67, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19670369

RESUMO

A proteomic approach was applied to explore the signalling pathways elicited by lowering O(2) in endothelial cells. Endothelial cells isolated from native umbilical cords were subjected to 21, 5, or 1% O(2) for 24 h. 2-D PAGE was performed and candidate proteins were identified using LC-MS/MS. Lowering of O(2) from 21 to 5% induced upregulation of cofilin-1, cyclophilin A, tubulin and tubulin fragments, a fragment of glucose-regulated protein 78 (Grp78) and calmodulin. The upregulation of Grp78 suggested that ER stress proteins were altered and indeed Grp94 and caspase 12 expression were increased in cells exposed to 5% O(2). The presence of ER stress is also supported by findings of blunted caffeine-evoked ER calcium release in cells exposed to 5 and 1% O(2). Exposure to 1% O(2) caused increases in cofilin-1, cyclophilin A, and caspase 12 as well as a decrease of beta-actin, but it did not alter the expression of calmodulin, tubulin, Grp78, and Grp94. Incubation with CoCl(2), a stabilizer of the hypoxia-inducible factor, increased the expression of several of the proteins. The present investigations reveal that lowering O(2), probably in part through hypoxia-inducible factor, alter the expression of a series of proteins mainly involved in cytoskeletal changes (e.g. cofilin-1, tubulin, and beta-actin) and in ER stress/apoptosis (e.g. Grp78/94, caspase 12, and cyclophilin A).


Assuntos
Proteínas do Citoesqueleto/metabolismo , Retículo Endoplasmático/metabolismo , Células Endoteliais/metabolismo , Proteínas de Choque Térmico/metabolismo , Hipóxia , Oxigênio/metabolismo , Sequência de Aminoácidos , Cálcio/metabolismo , Calmodulina/metabolismo , Caspase 12/metabolismo , Células Cultivadas , Ciclofilina A/metabolismo , Chaperona BiP do Retículo Endoplasmático , Células Endoteliais/citologia , Feminino , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia , Glicoproteínas de Membrana/metabolismo , Dados de Sequência Molecular , Gravidez , Proteômica/métodos , Transdução de Sinais/fisiologia , Cordão Umbilical/citologia
11.
FEBS Lett ; 580(5): 1485-9, 2006 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-16469315

RESUMO

Human extracellular superoxide dismutase (EC-SOD) is involved in the defence against oxidative stress induced by the superoxide radical. The protein is a homotetramer stabilised by hydrophobic interactions within the N-terminal region. During the purification of EC-SOD from human aorta, we noticed that material with high affinity for heparin-Sepharose formed not only a tetramer but also an octamer. Analysis of the thermodynamic stability of the octamer suggested that the C-terminal region is involved in formation of the quaternary structure. In addition, we show that the octamer is composed of both aEC-SOD and iEC-SOD folding variants. The presence of the EC-SOD octamer with high affinity may represent a way to influence the local concentration of EC-SOD to protect tissues specifically sensitive to oxidative damage.


Assuntos
Superóxido Dismutase/química , Aorta/enzimologia , Dimerização , Humanos , Dobramento de Proteína , Estrutura Quaternária de Proteína , Transporte Proteico , Sefarose/análogos & derivados , Superóxido Dismutase/metabolismo , Termodinâmica
12.
Hypoxia (Auckl) ; 2: 143-151, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-27774473

RESUMO

BACKGROUND: A reduced oxygen supply puts patients at risk of tissue hypoxia, organ damage, and even death. In response, several changes are activated that allow for at least partial adaptation, thereby increasing the chances of survival. We aimed to investigate whether the arginine vasopressin marker, copeptin, can be used as a marker of the degree of acclimatization/adaptation in rats exposed to hypoxia. METHODS: Sprague-Dawley rats were exposed to 10% oxygen for up to 48 hours. Arterial and right ventricular pressures were measured, and blood gas analysis was performed at set time points. Pulmonary changes were investigated by bronchoalveolar lavage, wet and dry weight measurements, and lung histology. Using a newly developed specific rat copeptin luminescence immunoassay, the regulation of vasopressin in response to hypoxia was studied, as was atrial natriuretic peptide (ANP) by detecting mid-regional proANP. RESULTS: With a decreasing oxygen supply, the rats rapidly became cyanotic and inactive. Despite continued exposure to 10% oxygen, all animals recuperated within 16 hours and ultimately survived. Their systemic blood pressure fell with acute (5 minutes) hypoxia but was partially recovered over time. In contrast, right ventricular pressures increased with acute (5 minutes) hypoxia and normalized after 16 hours. No signs of pulmonary inflammation or edema were found despite prolonged hypoxia. Whereas copeptin levels increased significantly after acute (5 minutes) hypoxia and then returned to near baseline after 16 hours, mid-regional proANP levels were even further increased after 16 hours of exposure to hypoxia. CONCLUSION: Plasma copeptin is a sensitive marker of acute (5 minutes) exposure to severe hypoxia, and subsequent regulation can indicate recovery. Copeptin levels can therefore reflect clinical and physiological changes in response to hypoxia and indicate recovery from ongoing hypoxic exposure.

13.
Pulm Circ ; 3(4): 898-907, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25006406

RESUMO

Pulmonary hypertension (PH) is an incurable disease that often leads to right ventricular hypertrophy and right heart failure. This study investigated single versus combined therapy with sildenafil and erythropoietin on hypoxia-induced pulmonary hypertension in mice. Mice were randomized into 5 groups and exposed to either hypoxia (10% oxygen) or normoxia for a total of 5 weeks. Hypoxic mice were treated with saline solution, erythropoietin (500 IU/kg 3 times weekly), sildenafil (10 mg/kg daily), or a combination of the two drugs for the last 2 weeks of hypoxic exposure. We measured right ventricular pressures using right heart catheterization, and the ventilatory response to hypoxia was recorded via whole-body plethysmography. Histological analyses were performed to elucidate changes in pulmonary morphology and appearance of right heart hypertrophy. Plasma levels of cardiotrophin-1 and atrial natriuretic peptide were quantified. Treatment with either erythropoietin or sildenafil alone lowered the hypoxia-induced increase of pulmonary pressure and reduced pulmonary edema formation, pulmonary vascular remodeling, and right ventricular hypertrophy. Notably, the combination of the two drugs had the most prominent effect. Changes in cardiotrophin-1 and atrial natriuretic protein levels confirmed these observations. The combination treatment with erythropoietin and sildenafil demonstrated an attenuation of the development of hypoxia-induced PH in mice that was superior to that observed for either drug when given alone.

14.
Am J Physiol Heart Circ Physiol ; 293(5): H2894-903, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17720765

RESUMO

The present study addressed whether chronic hypoxia is associated with reduced nitric oxide (NO) release due to decreased activation of endothelial NO synthase (eNOS). Primary cultures of endothelial cells from human umbilical veins (HUVECs) were used and exposed to different oxygen levels for 24 h, after which NO release, intracellular calcium, and eNOS activity and phosphorylation were measured after 24 h. Direct measurements using a NO microsensor showed that in contrast to 1-h exposure to 5% and 1% oxygen (acute hypoxia), histamine-evoked (10 microM) NO release from endothelial cells exposed to 5% and 1% oxygen for 24 h (chronic hypoxia) was reduced by, respectively, 58% and 40%. Furthermore, chronic hypoxia also lowered the amount and activity of eNOS enzyme. The decrease in activity could be accounted for by reduced intracellular calcium and altered eNOS phosphorylation. eNOS Ser(1177) and eNOS Thr(495) phosphorylations were reduced and increased, respectively, consistent with lowered enzyme activity. Akt kinase, which can phosphorylate eNOS Ser(1177), was also decreased by hypoxia, regarding both total protein content and the phosphorylated (active) form. Moreover, the protein content of beta- actin, which is known to influence the activity of eNOS, was almost halved by hypoxia, further supporting the fall in eNOS activity. In conclusion, chronic hypoxia in HUVECs reduces histamine-induced NO release as well as eNOS expression and activity. The decreased activity is most likely due to changed eNOS phosphorylation, which is supported by decreases in Akt expression and phosphorylation. By reducing NO, chronic hypoxia may accentuate endothelial dysfunction in cardiovascular disease.


Assuntos
Células Endoteliais/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico/metabolismo , Oxigênio/metabolismo , Hipóxia Celular/fisiologia , Ativação Enzimática , Feminino , Humanos , Fosforilação , Gravidez
15.
J Biol Chem ; 279(14): 13705-10, 2004 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-14736885

RESUMO

The antioxidant enzyme extracellular superoxide dismutase (EC-SOD) is mainly found in the extracellular matrix of tissues. EC-SOD participates in the detoxification of reactive oxygen species by catalyzing the dismutation of superoxide radicals. The tissue distribution of the enzyme is particularly important because of the reactive nature of its substrate, and it is likely essential that EC-SOD is positioned at the site of superoxide production to prevent adventitious oxidation. EC-SOD contains a C-terminal heparin-binding region thought to be important for modulating its distribution in the extracellular matrix. This paper demonstrates that, in addition to binding heparin, EC-SOD specifically binds to type I collagen with a dissociation constant (K(d)) of 200 nm. The heparin-binding region was found to mediate the interaction with collagen. Notably, the bound EC-SOD significantly protects type I collagen from oxidative fragmentation. This expands the known repertoire of EC-SOD binding partners and may play an important physiological role in preventing oxidative fragmentation of collagen during oxidative stress.


Assuntos
Colágeno Tipo I/metabolismo , Estresse Oxidativo/fisiologia , Superóxido Dismutase/metabolismo , Animais , Anticorpos , Bovinos , Cromatografia de Afinidade , Colágeno Tipo I/imunologia , Espaço Extracelular/enzimologia , Heparina/metabolismo , Estrutura Terciária de Proteína , Coelhos , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/química
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