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1.
Geroscience ; 43(4): 1877-1897, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33837912

RESUMO

COVID-19-associated case fatality rates up to 48% were reported among nursing facility residents. During the first wave of the COVID-19 pandemic, routine SARS-CoV-2 testing in long-term care facilities in the Province of Salzburg and centralized hospitalization in the COVID-19 unit of the Paracelsus Medical University Salzburg (Austria) irrespective of symptoms was implemented. Baseline characteristics and the course of COVID-19 disease were assessed among hospitalized long-term care facility residents within the COVID-19 Registry of the Austrian Group Medical Tumor Therapy (AGMT; NCT04351529). Between the 24th of March and the 20th of April 2020, 50 COVID-19-positive residents were hospitalized. The median age was 84.5 years (range: 79-88) and the median number of comorbidities and baseline medication classes was 6 (IQR: 4-7) and 5 (IQR: 3-6), respectively. At admission, 31 residents (62%) were symptomatic, nine residents (18%) pre-symptomatic whereas ten residents (20%) remained asymptomatic. The 30-day mortality rate from hospitalization was 32% and significantly higher in symptomatic residents at admission when compared to asymptomatic residents including pre-symptomatic residents (48% [95% CI: 27-63%] versus 5% [95% CI: 0-15%], p=0.006). The Early Warning Score (EWS) at admission was associated with 30-day mortality: high risk: 100%, intermediate risk: 50% (95% CI: 0-78%), and low risk: 21% (95% CI: 7-32%) (p<0.001). In light of comparably low mortality rates between asymptomatic and pre-symptomatic hospitalized COVID-19-positive residents, we suggest the supply of comparable intensity and quality of monitoring and care in long-term care facilities as an alternative to immediate hospitalization upon a positive COVID-19 test in asymptomatic residents.


Assuntos
COVID-19 , Idoso de 80 Anos ou mais , Teste para COVID-19 , Hospitalização , Humanos , Assistência de Longa Duração , Pandemias , Políticas , Sistema de Registros , SARS-CoV-2
2.
Biochem Med (Zagreb) ; 30(2): 020502, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32550813

RESUMO

Laboratory analyses are crucial for diagnosis, follow-up and treatment decisions. Since mistakes in every step of the total testing process may potentially affect patient safety, a broad knowledge and systematic assessment of laboratory errors is essential for future improvement. In this review, we aim to discuss the types and frequencies of potential errors in the total testing process, quality management options, as well as tentative solutions for improvement. Unlike most currently available reviews on this topic, we also include errors in test-selection, reporting and interpretation/action of test results. We believe that laboratory specialists will need to refocus on many process steps belonging to the extra-analytical phases, intensifying collaborations with clinicians and supporting test selection and interpretation. This would hopefully lead to substantial improvements in these activities, but may also bring more value to the role of laboratory specialists within the health care setting.


Assuntos
Tomada de Decisão Clínica , Técnicas de Laboratório Clínico/normas , Erros Médicos/prevenção & controle , Flebotomia/normas , Centrifugação , Europa (Continente) , Humanos , Uso Excessivo dos Serviços de Saúde , Segurança do Paciente , Controle de Qualidade , Indicadores de Qualidade em Assistência à Saúde , Valores de Referência , Reprodutibilidade dos Testes
3.
Clin Biochem ; 80: 14-18, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32229197

RESUMO

INTRODUCTION: Too frequent HbA1c measurements may lead to unnecessary treatment modifications of diabetic patients. The aim of this study was to estimate the percentage of falsely elevated HbA1c results in two hospitals, Landeskrankenhaus/Uniklinikum Salzburg (LKH) and Landesklinik St. Veit (STV), as well as to retrospectively investigate the effect of an automated and an educative 60-day re-testing interval (RTI). METHODS: The amount of estimated falsely elevated results (eFER), based on odds calculated using the baseline and the follow-up values and the time between these measurements, the number of HbA1c re-testings within 60 days as well as the overall number of ordered and performed HbA1c analyses were calculated. In LKH, an automated algorithm cancelling inappropriate HbA1c testing was applied, and in STV, educational actions were taken. RESULTS: Before RTI-implementation, eFER were 0.9% and 2.1% and within-60-days-re-testing were 15.0% and 7.4% of cases in LKH and STV, respectively. After RTI-implementation, these numbers decreased to 0.2% (p < .001) and 1.8% (p = .869) and within-60-days-re-testing decreased to 1.1% (p < .001) and 3.6% (p = .003) in LKH and STV, respectively. Median monthly HbA1c measurements decreased by 15.8% (p < .001) and 21.1% (p = .002) in LKH and STV, respectively. CONCLUSION: Both the educational and the automated 60-day-RTI were proven to be efficient in reducing overall HbA1c measurements, re-testing within 60 days and eFER.


Assuntos
Diabetes Mellitus Tipo 2/diagnóstico , Hemoglobinas Glicadas/análise , Idoso , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/terapia , Reações Falso-Positivas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Probabilidade , Estudos Retrospectivos , Procedimentos Desnecessários
4.
Clin Chim Acta ; 505: 100-107, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32084382

RESUMO

INTRODUCTION: The appropriate use of laboratory diagnostics is increasingly at stake. The aim of this study was to depict some paradigmatic examples of under- and overutilization, as well as possible solutions across Europe. METHODS: We collected six examples from five European countries where a rise or decline of orders for specific laboratory parameters was observed after organizational changes but without evidence of changes in patient collective characteristics as source of this variation. RESULTS: The collected examples were the following: 1-Germany) Switch from a Brain-Natriuretic-Peptide assay to NT-pro Brain-Natriuretic-Peptide assay, resulting in a 374% increase in these analytics; 2-Spain) Implementation of a gatekeeping strategy in tumor marker diagnostics, resulting in a 15-61% reduction of these diagnostics; 3-Croatia) Stepwise elimination of creatine-kinase-MB assay from the laboratory portfolio; 4-UK) Removal of γ-glutamyl transferase from a "liver function" profile, resulting in 82% reduction of orders; 5-Austria) Implementation of a new device for rapid Influenza-RNA detection, resulting in a 450% increase of Influenza testing; 6-Spain) Insourcing of 1,25-(OH)2-Vitamin D measurements, leading to a 378% increase of these analyses. CONCLUSION: The six paradigmatic examples described in this manuscript show that availability of laboratory resources may considerably catalyze the demand, thus underscoring that inappropriate use of laboratory resources may be commonplace in routine laboratories all across Europe and most probably beyond. They also demonstrate that the application of simple strategies may assist in overcoming this issue. We believe that laboratory specialists need to refocus on the extra-analytical parts of the testing process and engage more in interdisciplinary patient-care.


Assuntos
Técnicas de Laboratório Clínico/estatística & dados numéricos , Testes Diagnósticos de Rotina/estatística & dados numéricos , Prescrição Inadequada/estatística & dados numéricos , Biomarcadores Tumorais/análise , Creatina Quinase Forma MB/análise , Europa (Continente) , Humanos , Hidroxicolecalciferóis/análise , Influenza Humana/sangue , Peptídeo Natriurético Encefálico/análise , Fragmentos de Peptídeos/análise , gama-Glutamiltransferase/análise
5.
Int J Infect Dis ; 84: 75-79, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31054966

RESUMO

OBJECTIVE: HIV positive individuals, particularly men having sex with men (MSM), are at increased risk of sexually transmitted infections (STIs) at genital and extra-genital sites. Data on anorectal Ureaplasma infections are lacking. The aim of our study was to characterize anal Ureaplasma positivity among a cohort of HIV positive MSM and evaluate possible association with papillomavirus infection at the same site. METHODS: Anal swab samples, collected as part of routine screening for Chlamydia trachomatis and Neisseria gonorrhea, were additionally tested for HPV genotypes as well as for Ureaplasma and Mycoplasma using nucleic acid amplification method. RESULTS: Out of a total of 222 study participants, 195 (89%, 95% CI (84.9-93.2)) were positive for HPV, approximately three quarter being high-risk genotypes. Forty three individuals (19.4%, 95% CI (14.4-24.3)) harbored Ureaplasma spp. Infection with high-risk HPV types was significantly associated with co-presence of Ureaplasma with an odds ratio (95% confidence-interval) of 2.59 (1.03-6.54), P = 0.04. CONCLUSION: Besides a high predominance of HPV infection, asymptomatic HIV positive MSM had a high prevalence of anal Ureaplasma positivity. Concomitant infections with high-risk HPV genotypes were common and statistically significant. The role of this co-existence as a potential risk factor for anal carcinogenesis needs further elucidation.


Assuntos
Canal Anal/microbiologia , Soropositividade para HIV/complicações , Homossexualidade Masculina , Infecções por Papillomavirus/etiologia , Ureaplasma/isolamento & purificação , Adulto , Soropositividade para HIV/microbiologia , Humanos , Masculino , Pessoa de Meia-Idade
6.
J Acquir Immune Defic Syndr ; 75(1): e13-e20, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-27798431

RESUMO

BACKGROUND: Hemeoxygenase-1 (HO-1) has recently been identified as a major driver of metaflammation and obesity-related insulin resistance (IR). Drug-induced IR increases cardiovascular risk within the HIV-1-infected population receiving antiretroviral therapy (ART). We therefore investigated a possible role of HO-1 in ART-induced IR. METHODS: Effects of HIV-1 protease inhibitor ritonavir and integrase inhibitor raltegravir (RAL) on expression levels of HO-1 and proinflammatory cytokines, including interleukin 1ß (IL-1ß), IL-6, IL-8, tumor necrosis factor-α (TNFα), chemokine (C-C motif) ligand 5 (CCL5), and monocyte chemotactic protein 1 (MCP-1), were studied in monocyte and hepatocyte cell lines. Plasma levels of HO-1 and inflammatory markers were measured in insulin-resistant and insulin-sensitive HIV-1-infected patients under ART and seronegative controls. RESULTS: We show that, in contrast to RAL, ritonavir treatment significantly increases mRNA expression levels of HO-1, IL-8, TNFα, CCL5, and MCP-1 in vitro in a dose-dependent manner. HO-1 plasma levels were significantly higher in insulin-resistant compared to insulin-sensitive patients on ritonavir-boosted ART (lopinavir/ritonavir group: 3.90 ± 1.15 vs 2.56 ± 1.07 ng/mL, P < 0.005 and darunavir/ritonavir group: 3.16 ± 1.37 vs 2.28 ± 1.23 U/mL, P < 0.05) and were correlated with expression levels of TNFα in individuals on ritonavir-boosted ART (lopinavir/ritonavir group: r = 0.108, P < 0.05 and darunavir/ritonavir group: r = 0.221, P < 0.05) but not in HIV-1-infected individuals receiving RAL or in seronegative controls. IMPLICATIONS: HIV-1-infected patients on stable ART are often faced with non-AIDS-related metabolic comorbidities, increasing their individual cardiovascular risk. Here, we provide insight into a novel mechanism of ritonavir-induced IR involving proinflammatory properties of HO-1. Our initial observations might also provide prognostic value in the future to identify patients at risk for the development type 2 diabetes mellitus.


Assuntos
Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Inibidores da Protease de HIV/efeitos adversos , Heme Oxigenase-1/análise , Resistência à Insulina , Ritonavir/efeitos adversos , Linhagem Celular , Citocinas/análise , Perfilação da Expressão Gênica , Infecções por HIV/virologia , Inibidores da Protease de HIV/administração & dosagem , HIV-1/isolamento & purificação , Hepatócitos/enzimologia , Hepatócitos/imunologia , Humanos , Monócitos/enzimologia , Monócitos/imunologia , Ritonavir/administração & dosagem
7.
Cell ; 158(1): 25-40, 2014 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-24995976

RESUMO

Obesity and diabetes affect more than half a billion individuals worldwide. Interestingly, the two conditions do not always coincide and the molecular determinants of "healthy" versus "unhealthy" obesity remain ill-defined. Chronic metabolic inflammation (metaflammation) is believed to be pivotal. Here, we tested a hypothesized anti-inflammatory role for heme oxygenase-1 (HO-1) in the development of metabolic disease. Surprisingly, in matched biopsies from "healthy" versus insulin-resistant obese subjects we find HO-1 to be among the strongest positive predictors of metabolic disease in humans. We find that hepatocyte and macrophage conditional HO-1 deletion in mice evokes resistance to diet-induced insulin resistance and inflammation, dramatically reducing secondary disease such as steatosis and liver toxicity. Intriguingly, cellular assays show that HO-1 defines prestimulation thresholds for inflammatory skewing and NF-κB amplification in macrophages and for insulin signaling in hepatocytes. These findings identify HO-1 inhibition as a potential therapeutic strategy for metabolic disease.


Assuntos
Heme Oxigenase-1/metabolismo , Resistência à Insulina , Proteínas de Membrana/metabolismo , Obesidade/complicações , Tecido Adiposo/metabolismo , Animais , Dieta Hiperlipídica , Hepatócitos/metabolismo , Humanos , Inflamação/metabolismo , Fígado/metabolismo , Macrófagos/metabolismo , Doenças Metabólicas/metabolismo , Doenças Metabólicas/fisiopatologia , Camundongos , Camundongos Knockout , Obesidade/fisiopatologia , Espécies Reativas de Oxigênio/metabolismo
8.
J Nutr Biochem ; 24(1): 112-7, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22819549

RESUMO

Mutual clinical and molecular interactions between iron and glucose metabolism have been reported. We aimed to investigate a potential effect of glucose on iron homeostasis. We found that serum iron concentrations gradually decreased over 180 min after the administration of 75 g of glucose from 109.8 ± 45.4 mg/L to 94.4 ± 40.4 mg/L (P<.001; N=40) but remained unchanged in control subjects receiving tap water (N=21). Serum hepcidin, the key iron regulatory hormone which is mainly derived from hepatocytes but also expressed in pancreatic ß-cells, increased within 120 min after glucose ingestion from 19.7 ± 9.9 nmol/L to 31.4 ± 21.0 nmol/L (P<.001). In cell culture, glucose induced the secretion of hepcidin and insulin into the supernatant of INS-1E cultures, but did not change the amount of hepcidin detectable in the hepatocyte cell culture HepG2. We additionally confirmed the expression of hepcidin in a human islet cell preparation. These results suggest that glucose acts as a regulator of serum iron concentrations, most likely by triggering the release of hepcidin from ß-cells.


Assuntos
Peptídeos Catiônicos Antimicrobianos/metabolismo , Glucose/metabolismo , Ferro/sangue , Adulto , Animais , Peptídeos Catiônicos Antimicrobianos/genética , Células Cultivadas , Feminino , Glucose/farmacologia , Teste de Tolerância a Glucose , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Hepcidinas , Homeostase/efeitos dos fármacos , Humanos , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Insulinoma/tratamento farmacológico , Insulinoma/metabolismo , Masculino , Pessoa de Meia-Idade , Ratos
9.
Arterioscler Thromb Vasc Biol ; 32(6): 1535-44, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22460558

RESUMO

OBJECTIVE: Genetic studies implicated upstream stimulatory factor 1 (USF1) in familial combined hyperlipidemia because the rs2073658 minor allele was associated with reduced risk of familial combined hyperlipidemia and related disorders. The molecular mechanisms whereby rs2073658 influences trait expression have remained elusive. METHODS AND RESULTS: Plasma lipids, rs2073658 genotypes (N=372), and hepatic transcript levels (N=96) of USF1 and genes involved in hepatic lipoprotein production were determined in obese subjects. The rs2073658 minor allele was associated with reduced plasma triglycerides (TGs) (P<0.001), hepatic USF1 (P<0.01), and microsomal TG transfer protein transcript levels (P<0.05). Functional studies in human hepatocellular carcinoma cells showed that rs2073658 is located in a forkhead box A2 (FOXA2) binding site and that major allele constructs displayed higher transcriptional activity than minor allele constructs. Knockdown of FOXA2 reduced the activity of major, but not minor allele constructs. Furthermore, an interaction between hepatic FOXA2 transcript levels and rs2073658 minor allele carrier status on hepatic USF1 transcript levels was observed in vivo (P<0.05). USF1 activated the transcription of FOXA2 and FOXA2 strongly activated the transcription of microsomal TG transfer protein. CONCLUSIONS: A feed-forward loop comprising activation of USF1 transcription by FOXA2 and activation of FOXA2 transcription by USF1, driving microsomal TG transfer protein expression, is modulated by rs2073658. Hence, rs2073658 likely influences hepatic TG secretion.


Assuntos
Hiperlipidemia Familiar Combinada/genética , Fígado/metabolismo , Obesidade/genética , Polimorfismo de Nucleotídeo Único , Fatores Estimuladores Upstream/genética , Adulto , Idoso , Análise de Variância , Áustria , Sítios de Ligação , Proteínas de Transporte/metabolismo , Distribuição de Qui-Quadrado , Retroalimentação Fisiológica , Feminino , Frequência do Gene , Predisposição Genética para Doença , Células Hep G2 , Fator 3-beta Nuclear de Hepatócito/genética , Fator 3-beta Nuclear de Hepatócito/metabolismo , Humanos , Hiperlipidemia Familiar Combinada/sangue , Modelos Lineares , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-Idade , Obesidade/sangue , Fenótipo , Regiões Promotoras Genéticas , Interferência de RNA , RNA Mensageiro/metabolismo , Ativação Transcricional , Transfecção , Triglicerídeos/sangue
10.
J Biol Chem ; 286(50): 42923-36, 2011 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-22009745

RESUMO

Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) is a transcriptional coactivator that contributes to the regulation of numerous transcriptional programs including the hepatic response to fasting. Mechanisms at transcriptional and post-transcriptional levels allow PGC-1α to support distinct biological pathways. Here we describe a novel human liver-specific PGC-1α transcript that results from alternative promoter usage and is induced by FOXO1 as well as glucocorticoids and cAMP-response element-binding protein signaling but is not present in other mammals. Hepatic tissue levels of novel and wild-type transcripts were similar but were only moderately associated (p < 0.003). Novel mRNA levels were associated with a polymorphism located in its promoter region, whereas wild-type transcript levels were not. Furthermore, hepatic PCK1 mRNA levels exhibited stronger associations with the novel than with the wild-type transcript levels. Except for a deletion of 127 amino acids at the N terminus, the protein, termed L-PGC-1α, is identical to PGC-1α. L-PGC-1α was localized in the nucleus and showed coactivation properties that overlap with those of PGC-1α. Collectively, our data support a role of L-PGC-1α in gluconeogenesis, but functional differences predicted from the altered structure suggest that L-PGC-1α may have arisen to adapt PGC-1α to more complex metabolic pathways in humans.


Assuntos
Proteínas de Choque Térmico/metabolismo , Fígado/metabolismo , Isoformas de Proteínas/metabolismo , Fatores de Transcrição/metabolismo , 8-Bromo Monofosfato de Adenosina Cíclica/farmacologia , Animais , Northern Blotting , Imunoprecipitação da Cromatina , Dexametasona/farmacologia , Feminino , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/genética , Genótipo , Proteínas de Choque Térmico/genética , Células Hep G2 , Humanos , Immunoblotting , Técnicas In Vitro , Camundongos , Microscopia de Fluorescência , Dados de Sequência Molecular , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Isoformas de Proteínas/genética , RNA Mensageiro/genética , Ratos , Fatores de Transcrição/genética
11.
Acta Ophthalmol ; 89(4): e344-9, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21232084

RESUMO

PURPOSE: To determine whether different complement factor H (CFH) genotypes play a role in treatment of age-related macular degeneration (AMD) with intravitreal bevacizumab. METHODS: In this prospective study, we included 197 patients with exudative AMD and treated with 1.25 mg intravitreal bevacizumab at 6-week intervals until choroidal neovascularization (CNV) was no longer active. In all patients, ophthalmological examinations, visual acuity, optical coherence tomography (OCT), fundus photography and fluorescein angiography were performed. Single nucleotide polymorphism (SNP) genotyping was performed using restriction fragment length polymorphism (RFLP) analysis of polymerase chain reaction (PCR) products. RESULTS: Age, gender and baseline mean visual acuity were similar among the three CFH genotypes. There was no significant difference in underlying lesion type of CNV, lesion size, number of injections or macula thickness. When examining the effect of genotype on post-treatment visual acuities, we observed a significant worse outcome for distance and reading visual acuity in the CFH 402HH genotype group. The number of patients who lost 3 or more lines in distance and reading visual acuity testing was significantly higher in the CFH 402HH (41%, 46%) genotype group than in patients with the CFH 402YY (28%, 26%) and CFH 402YH (26%, 24%) genotype. CONCLUSIONS: In addition to the higher risk for exudative AMD in patients with the CFH 402HH genotype that was found in previous studies, our results show that the CFH 402HH genotype also correlates with lower visual acuity outcome after treatment with bevacizumab, suggesting that pharmacogenetics of CFH plays a role in response to treatment of wet AMD.


Assuntos
Inibidores da Angiogênese/administração & dosagem , Anticorpos Monoclonais/administração & dosagem , Polimorfismo de Nucleotídeo Único , Degeneração Macular Exsudativa/tratamento farmacológico , Degeneração Macular Exsudativa/genética , Idoso , Anticorpos Monoclonais Humanizados , Bevacizumab , Fator H do Complemento/genética , Feminino , Angiofluoresceinografia , Genótipo , Humanos , Injeções Intravítreas , Masculino , Farmacogenética , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Estudos Prospectivos , Tomografia de Coerência Óptica , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Acuidade Visual/fisiologia
12.
J Mol Med (Berl) ; 87(3): 299-306, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19082571

RESUMO

Peroxisome proliferator-activated receptor-gamma co-activator-1 (PGC-1) alpha and -beta play pivotal roles in the regulation of intermediary metabolism. We have previously shown that PGC-1alpha-mediated upregulation of beta-cell sterol element binding protein (SREBP) gene expression impairs insulin secretion via increased transcription of uncoupling protein 2 (UCP2). PGC-1beta, in contrast to PGC-1alpha, directly binds to and acts as a co-activator of SREBPs and the forkhead transcription factor 2A (FOXA2) involved in pancreas development and function. To address a possible role of PGC-1beta in beta-cell function, we determined islet gene expression levels of PGC-1alpha, PGC-1beta, SREBPs, FOXA2, FOXO1, UCP2 as well as granuphilin, a critical component of the insulin secretory machinery, in Zucker diabetic fatty rats (ZDF). In comparison to controls, mRNA levels of all genes studied except for FOXA2 and FOXO1 were increased in islets of obese, fa/fa ZDF rats. The transcriptional activities of the UCP2 and granuphilin promoters were assessed in INS-1E cells in response to PGC-1beta overexpression and small interference RNA (siRNA)-mediated gene silencing. PGC-1beta as well as SREBP-1c and -2 increased transcription from the UCP2 promoter in INS-1E cells. Transient transfection of PGC-1beta-specific siRNAs significantly decreased SREBP-2-mediated transcriptional activation of the UCP2 gene. Furthermore PGC-1beta, SREBP-1c, and FOXA2 overexpression augmented granuphilin promoter activity, whereas siRNA-mediated gene knockdown of PGC-1beta reduced the effects of SREBP-1c and FOXA2 on granuphilin gene transcription and significantly increased glucose-stimulated insulin release from INS-1E cells. Our results support a role of PGC-1beta in the regulation of insulin secretion via upregulation of UCP2 and granuphilin gene expression.


Assuntos
Glucose/farmacologia , Insulina/metabolismo , Proteínas de Ligação a RNA/metabolismo , Fatores de Transcrição/metabolismo , Animais , Western Blotting , Linhagem Celular Tumoral , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Expressão Gênica , Fator 3-alfa Nuclear de Hepatócito/genética , Fator 3-alfa Nuclear de Hepatócito/metabolismo , Secreção de Insulina , Insulinoma/genética , Insulinoma/metabolismo , Insulinoma/patologia , Canais Iônicos/genética , Canais Iônicos/metabolismo , Ilhotas Pancreáticas/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Modelos Biológicos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , RNA Interferente Pequeno/genética , Proteínas de Ligação a RNA/genética , Ratos , Ratos Zucker , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Fatores de Transcrição/genética , Transfecção , Proteína Desacopladora 2 , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo
13.
Endocrinology ; 147(2): 966-76, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16282353

RESUMO

A role of uncoupling protein 2 (UCP2) as negative modulator of insulin secretion has been suggested, but the transcriptional pathways regulating beta-cell UCP2 gene expression have been established in rodents only. We show here that the underlying sequence motifs are not conserved in the human gene and provide evidence for regulatory mechanisms involving the transcriptional cofactor peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1alpha). PGC-1alpha potentiates thyroid hormone (T(3))-mediated transcriptional activation of the human UCP2 gene in INS-1E cells. Two thyroid hormone response elements (TREs) located at -322/-317 (TRE1) and -170/-165 (TRE2) were identified, and mutation of either TRE1 or TRE2 abrogated the stimulatory effect of T(3) treatment. Furthermore, two E-box motifs at -911/-906 (E1) and -743/-738 (E2) are involved in the regulation of UCP2 gene expression by sterol regulatory element binding protein isoforms (SREBP)-1a, -1c, and -2. Mutational analysis revealed that the presence of either E1 or E2 is sufficient to mediate activation of UCP2 gene transcription by nuclear active SREBPs. PGC-1alpha coactivates liver X receptor-mediated expression of SREBP-1c as well as dexamethasone-stimulated SREBP-2 expression in INS-1E cells. These transcriptional responses are antagonized by orphan nuclear receptor short heterodimer partner overexpression, which might explain its positive effects on glucose-stimulated insulin secretion in beta-cells overexpressing UCP2. We also provide evidence that despite a lack of sequence homology within the regulatory region, the principal mechanisms regulating UCP2 gene expression are similar in rats and humans, being consistent with a role for UCP2 as a modulator of insulin secretion in humans.


Assuntos
Proteínas de Choque Térmico/fisiologia , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas Mitocondriais/genética , Regiões Promotoras Genéticas/genética , Sequências Reguladoras de Ácido Nucleico/genética , Fatores de Transcrição/fisiologia , Animais , Linhagem Celular Tumoral , Regulação da Expressão Gênica/fisiologia , Humanos , Secreção de Insulina , Células Secretoras de Insulina/citologia , Canais Iônicos , Proteínas de Membrana Transportadoras/metabolismo , Proteínas Mitocondriais/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Ratos , Especificidade da Espécie , Ativação Transcricional/genética , Ativação Transcricional/fisiologia , Tri-Iodotironina/metabolismo , Proteína Desacopladora 2
14.
Biochem J ; 381(Pt 2): 357-63, 2004 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-15084148

RESUMO

The expression of SREBP-1 (sterol-regulatory-element-binding protein-1) isoforms differs between tissues and cultured cell lines in that SREBP-1a is the major isoform in established cell lines, whereas SREBP-1c predominates in liver and most other human tissues. SREBP-1c is transcriptionally less active than SREBP-1a, but is a main mediator of hepatic insulin action and is selectively up-regulated by LXR (liver X receptor) agonists. LXR-mediated transactivation is co-activated by PGC-1alpha (peroxisome-proliferator-activated receptor-gamma co-activator-1alpha), which displays deficient expression in skeletal-muscle-derived cell lines. In the present paper, we show that PGC-1alpha expression is also deficient in HepG2 cells and in a human brown adipocyte cell line (PAZ6). In transient transfection studies, PGC-1alpha selectively amplified the LXR-mediated transcription from the human SREBP-1c promoter in HepG2 and PAZ6 cells via two LXR-response elements with extensive similarity to the respective murine sequence. Mutational analysis showed that the human LXR-response element-1 (hLXRE-1) was essential for co-activation of LXR-mediated SREBP-1c gene transcription by PGC-1alpha. Ectopic overexpression of PGC-1alpha in HepG2 cells enhanced basal SREBP-1c and, to a lesser extent, -1a mRNA expression, but only SREBP-1c expression was augmented further in an LXR/RXR (retinoic X receptor)-dependent fashion, thereby inducing mRNA abundance levels of SREBP-1c target genes, fatty acid synthase and acetyl-CoA carboxylase. These results indicate that PGC-1alpha contributes to the regulation of SREBP-1 gene expression, and can restore the SREBP-1 isoform expression pattern of HepG2 cells to that of human liver.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/genética , Carcinoma Hepatocelular/genética , Proteínas de Ligação a DNA/genética , Regulação Neoplásica da Expressão Gênica/genética , Proteínas de Choque Térmico/fisiologia , Neoplasias Hepáticas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia , Tecido Adiposo/química , Tecido Adiposo/citologia , Tecido Adiposo/metabolismo , Adulto , Carcinoma Hepatocelular/patologia , Linhagem Celular , Linhagem Celular Tumoral , Humanos , Rim/química , Rim/citologia , Rim/embriologia , Rim/metabolismo , Fígado/química , Fígado/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Reto do Abdome/química , Reto do Abdome/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1
15.
Wien Klin Wochenschr ; 114 Suppl 4: 4-9, 2002.
Artigo em Alemão | MEDLINE | ID: mdl-15499992

RESUMO

Obesity has become the most prevalent nutritional disorder in post-industrialised societies and it is associated with the development of severe and costly complications such as type 2 diabetes mellitus and coronary heart disease or cancer. A large proportion of the risk of obesity is determined by the genetic susceptibility of an individual, but environmental factors conducive for the disorder play an important role in its phenotypic expression. Several candidate genes emerged from studies in animal models of obesity, but human pathophysiology is likely to be more complex. Thus, most cases of human obesity probably result from subtle interactions of susceptibility genes with environmental factors favouring deposition of excess calories as fat. The recent surge of obesity may relate to past evolutionary pressure which favoured selection of mechanisms defending body-weight against caloric restriction rather than against caloric excess. Rapidly developing new techniques in quantitative genetics and growing information from functional genomics will help to understand the interaction of environmental factors with signalling networks that regulate energy metabolism. The role of previously unknown pathways in the aetiology of obesity will be uncovered. The typing of numerous genetic variants will become possible and allow individual risk assessment for obesity and/or its associated disorders. Thus, rational and individually tailored therapies may be developed to combat obesity and its associated disorders.


Assuntos
Obesidade/genética , Obesidade/fisiopatologia , Adulto , Animais , Índice de Massa Corporal , Criança , Diabetes Mellitus Tipo 2/etiologia , Modelos Animais de Doenças , Metabolismo Energético , Meio Ambiente , Feminino , Predisposição Genética para Doença , Humanos , Hiperfagia/etiologia , Leptina/genética , Masculino , Camundongos , Camundongos Knockout , Mutação , Obesidade/complicações , Obesidade/epidemiologia , Obesidade/metabolismo , Obesidade/terapia , Fenótipo , Polimorfismo Genético , Prevalência , Pró-Opiomelanocortina/genética , Receptores de Superfície Celular/genética , Receptores para Leptina , Medição de Risco , Fatores de Risco , Termogênese
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