234 resultados para LPS


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Given the spread of antibiotic resistance in bacterial pathogens, antimicrobial peptides that can also modulate the immune response may be a novel approach for effectively controlling periodontal infections. In the present study, we used a three-dimensional (3D) co-culture model of gingival epithelial cells and fibroblasts stimulated with Aggregatibacter actinomycetemcomitans lipopolysaccharide (LPS) to investigate the anti-inflammatory properties of human beta-defensin-3 (hBD-3) and cathelicidin (LL-37) and to determine whether these antimicrobial peptides can act in synergy. The 3D co-culture model composed of gingival fibroblasts embedded in a collagen matrix overlaid with gingival epithelial cells had a synergistic effect with respect to the secretion of IL-6 and IL-8 in response to LPS stimulation compared to fibroblasts and epithelial cells alone. The 3D co-culture model was stimulated with non-cytotoxic concentrations of hBD-3 (10 and 20 mu M) and LL-37 (0.1 and 0.2 mu M) individually and in combination in the presence of A. actinomycetemcomitans LPS. A multiplex ELISA assay was used to quantify the secretion of 41 different cytokines. hBD-3 and LL-37 acted in synergy to reduce the secretion of GRO-alpha, G-CSF, IP-10, IL-6, and MCP-1, but only had an additive effect on reducing the secretion of IL-8 in response to A. actinomycetemcomitans LPS stimulation. The present study showed that hBD-3 acted in synergy with LL-37 to reduce the secretion of cytokines by an LPS-stimulated 3D model of gingival mucosa. This combination of antimicrobial peptides thus shows promising potential as an adjunctive therapy for treating inflammatory periodontitis.

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Atualmente são conhecidas aproximadamente 10.000 substâncias do metabolismo secundário de invertebrados e microorganismos marinhos. Dentre os organismos marinhos estudados do ponto de vista químico e farmacológico, destacam-se, as esponjas, as ascídias, os briozoários e os octocorais. No entanto, pouco se sabe quanto ao potencial imunomodulador de compostos isolados de microrganismos marinhos, em especial daqueles isolados da costa brasileira. A propriedade anti-inflamatória de diferentes extratos brutos foi inicialmente avaliada pelo potencial destes compostos quanto à inibição da produção de óxido nítrico (NO) em linhagem de macrófagos, RAW 264.7. Posteriormente as amostras que se mostraram promissoras foram também avaliadas em relação ao potencial imunomodulador quanto a expressão de moléculas de superfície relacionadas migração (Mac-1 ou CD11b) e ativação celular (CD80 e CD86) em linhagens de macrófagos estimulados com LPS. Nossos resultados mostram que dentre as 289 amostras testadas apenas o extrato DLM33 e as substâncias Ma(M3%)J-MeOH e Dr(M3%)6-MeOH/H2O foram inicialmente considerados promissores quanto capacidade de inibir a síntese de NO por macrófagos. O extrato DLM33 foi capaz de de modular apenas a porcentagem de macrófagos positivos para CD80 na presença de LPS. No entanto, a substância Dr(M3%)6-MeOH/H2O não se mostrou eficiente quanto a modulação da expressão de moléculas de superfície Mac-1, CD80 e CD86. Surpreendentemente, a substância Ma(M3%)J-MeOH apresentou um potencial imunoestimulador quanto a expressão de Mac-1+/CD80+, mas não de CD86, em macrófagos sugerindo um possível efeito adjuvante desta substância. O efeito imunoestimulador da substância Ma(M3%)J-MeOH será futuramente investigado utilizando diferentes abordagens in vitro e in vivo para validar os resultados obtidos... (Resumo completo, clicar acesso eletrônico abaixo)

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Preeclampsia is a specific disorder of pregnancy, characterized by arterial hypertension and proteinuria detected after 20 weeks of gestation. This pathology is associated with hyperuricemia, higher levels of pro-inflammatory cytokines, enhanced leukocyte activation and oxidative stress. Adenosine deaminase (ADA) is an enzyme present in all human tissues and, it is involved with the maturation of the immune system. Although its function is not fully understood, ADA is considered an indicator of cellular inflammation and, its increased serum concentration is observed in inflammatory diseases, such as tuberculosis and rheumatoid arthritis. This study aimed to assess serum ADA levels in preeclamptic patients (PE) compared with normotensive pregnant (NT) and non-pregnant women (NP), and to correlate these values with TNF-α and IL-1β production. Ninety pregnant women were included: 60 were pre-eclamptic and 30 were normotensive matched for gestational age. As control group 20 healthy non-pregnant women matched with pregnant for age were included. Peripheral blood mononuclear cells (PMMC) obtained from the three groups studied were cultured with or without lipopolysaccharide (LPS) for 18h at 37oC, and TNF-α and IL-1β production was assessed in the supernatant of cultures by enzyme immunoassay (ELISA). ADA plasmatic concentration was determined by colorimetric method. The results show that ADA plasma levels were significantly higher in PE group compared with NT and NP groups. A positive correlation between ADA and uric acid levels was detected in preeclamptic women. There was no significant difference in relation to ADA levels when PE patients were classified in early and late-onset PE. The endogenous production of IL-1β and TNF-α by PBMC was significantly higher in PE group than in NT and NP women, showing the activation state of these cells in PE. LPS induced...(Complete abstract click electronic access below)

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Pre-eclampsia (PE) is a complication of human pregnancy characterized by hypertension and proteinuria after 20 weeks of gestation. Its incidence varies from 5% to 7% of pregnancies and is a major cause of morbidity and maternal and fetal mortality. This is a multisystemic disease, with focus on vascular dysfunction and is closely related to the exacerbated activation of the immune system. In addition to increased activation of monocytes and granulocytes, there is an elevated production of proinflammatory cytokines in pregnant women with PE. The nuclear transcription factor-kB (NF-kB) is present in the cells of the immune system and is responsible for transcription of genes related to inflammation. Whereas the PE is associated with intense inflammatory response, the use of substances modulating the activity of NF-kB factor could be useful in alleviating the inflammation present in these patients. Silibinin is the main component of silymarin, a polyphenolic extract obtained from fruits and seeds of Sylibum marianum with potent hepatoprotective, anti-inflammatory and anti-fibrotic activities. The silibinin mechanism of action includes the ability to inhibit NF-kB activation and, consequently, its migration to the nucleus. The objective of this study was to assess whether silibinin modulates the activity of NF-kB and the production of inflammatory cytokines in mononuclear cells of patients with PE. We evaluated 34 pregnant women with PE, 20 normotensive pregnant women (GN) and 15 non-pregnant women (NG). Peripheral blood mononuclear cells (PBMC) were obtained from those groups of women and cultured in the presence or absence of silibinin (5 uM or 50 uM) and stimulated or not with lipopolysaccharide (LPS) for 18 h to obtain supernatant for determination of tumor necrosis factor-alpha (TNF-α) and interleukin-1 (IL-1β) by enzyme immunoassay (ELISA). The cells were...(Complete abstract click electronic access below)

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O Brasil possui cerca de 8.000 quilômetros de costa litorânea, a segunda maior do mundo depois da Austrália. Apesar do território marítimo brasileiro apresentar 3,6 milhões de quilômetros quadrados de extensão, as pesquisas relacionadas ao levantamento de potenciais recursos brasileiros obtidos a partir de espécies marinhas ainda são incipientes. O interesse de empresas farmacêuticas por compostos isolados de microrganismos vem crescendo lentamente devido às dificuldades até então encontradas para o isolamento e cultivo dos mesmos. No entanto, com o avanço destas técnicas, recentes estudos demonstram que compostos isolados de microrganismos marinhos representam uma rica e ainda pouco explorada fonte de novos compostos bioativos (estima-se que apenas 1% dos microrganismos marinhos foram cultivados e identificados). Recentes estudos que apontam para o potencial farmacológico de compostos isolados de microrganismos nos instigaram à busca de novos fármacos com potencial imunoestimulador não apenas a partir de invertebrados, mas também de microrganismos marinhos e seus metabólitos secundários bioativos. Neste trabalho, após avaliação do potencial imunomodulador de extratos brutos derivados de microrganismos marinhos, obteve-se a substância pura Pirenocine A, isolada do fungo Penicillium paxilli, que mostrou-se promissora devido sua capacidade de diminuir a produção de óxido nítrico e citocinas pró-inflamatórias em macrófagos estimulados com LPS tanto no protocolo profilático quanto terapêutico ...

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Preeclampsia (PE) is a pregnancy specific syndrome characterized by a systemic inflammatory response, with higher intensity than that observed in normal pregnancy. Cells of the immune system, such as monocytes and granulocytes are endogenously activated and secrete high levels of free radicals and inflammatory cytokines. The objective of this study was to assess the activation state of monocytes from pregnant women with preeclampsia by endogenous expression of TLR2 e TLR4 receptors and to correlate the expression of TLR2 and TLR4 on monocytes surface of pregnant women with PE with the production of tumor necrosis factor-alpha (TNF- and interleukin-10 (IL-10) by these cells stimulated or not with peptidoglycan (PG) and lipopolysaccharide (LPS), as agonists agents of TLR2 and TLR4, respectively. We evaluated 15 pregnant women with PE, 15 normotensive pregnant women (NT) and 15 non-pregnant (NP). Peripheral blood monocytes were incubates in the presence or absence of LPS or PG. The supernatant obtained after 18h of culture was aspirated and used for TNF- and IL-10 determination by enzyme immunoassay (ELISA). The endogenous expression of TLR2 and TLR4 receptors was evaluated by flow cytometry. Our results showed significant highly concentrations of TNF- and TLR4 expression in monocytes of preeclamptic women when compared with NT and NP. Normal pregnant women presented higher levels of IL-10 in comparison with PE and NP groups. TLR2 expression was similar in the three groups studied. Therefore, our study highlights the important role of TLR4 in PE and the consequent high production of TNF- by monocytes of these patients, as well as the potential mechanism involving low levels of IL-10 in the pathophysiology of the disease. These observations demonstrate the strong link between the pathology of PE and the immune system of these patients

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A anemia falciforme (AF) é a doença hematológica hereditária crônica de maior prevalência no Brasil, causada por uma mutação pontual no gene da β-globina, levando as hemácias a adquirirem formato de foice quando em estado desoxigenado. Essa alteração estrutural causa aumento da adesão celular, hipóxia local, vaso-oclusão e alterações na coagulação. O quadro clínico dos pacientes é diversificado, predominando a dor causada pelo processo inflamatório agudo e crônico, além de complicações que podem ocasionar infarto de tecidos e órgãos, levando à morte. O único fármaco aprovado pelo FDA disponível para o tratamento da doença é a hidroxiuréia (HU), mas, devido a sua toxicidade, têm sido intensificadas as buscas por novas possibilidades terapêuticas. O fator de necrose tumoral alfa (TNF-α) é uma citocina pró-inflamatória presente em grande quantidade nos pacientes portadores da doença, e o óxido nítrico pode contribuir para vasodilatação e proteção vascular. Assim, propôs-se a síntese e avaliação farmacológica de candidatos a fármacos para o tratamento da AF, desenhados com o propósito de apresentar propriedades inibidoras do TNF-α e doadoras de óxido nítrico (NO). Foi avaliada a estabilidade química dos compostos sintetizados, em água, pH 1,2 e pH 7,4, sendo o Composto II o mais estável tanto em pH ácido como em água. Em pH básico, todos os compostos se mostraram instáveis. Os compostos III e VI apresentaram uma maior inibição da agregação plaquetária, atividade também atribuída à capacidade de doação de NO. O composto III foi o único a mostrar-se inibidor de TNF-α e IL-1β, em todas as concentrações avaliadas, e, também, mostrou-se inibidor de NO, no teste induzido por LPS. Diante de todos os ensaios realizados, o composto III é o mais promissor candidato a fármaco, entre os compostos sintetizados, para o tratamento dos sintomas da anemia falciforme.

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This study evaluated the effects of LLLT on the expressionof inflammatory cytokines related to the development of oralmucositis by gingival fibroblasts. Primary gingival fibroblastswere seeded on 24-well plates (105cells/well) for 24 h. Freshserum-free culture medium (DMEM) was then added, andcells were placed in contact with LPS (Escherichia coli,1 lgmL1), followed by LLLT irradiation (LaserTABLE—InGaAsP diode prototype—780 nm, 25 mW) delivering 0,0.5, 1.5 or 3 J cm². Cells without contact with LPS werealso irradiated with the same energy densities. Gene expres-sion of TNF- a, IL-1b, IL-6 and IL-8 was evaluated by Real-Time PCR, and protein synthesis of these cytokines wasdetermined by enzyme-linked immunosorbent (ELISA) assay.Data were statistically analyzed by the Kruskal– Wallis test,complemented by the Mann–Whitney test (P < 0.05). LPStreatment increased the gene expression and protein synthesisof TNF-a, IL-6 and IL-8, while the expression of IL-1b wasnot affected. For LPS-treated groups, LLLT promoted signif-icant decreases in the expression of TNF-a, IL-6, and IL-8 at1.5 J cm2and 3 J cm2. These results demonstrate thatLLLT promoted a beneficial biomodulatory effect on theexpression of inflammatory cytokines related to oral mucosi-tis by human gingival fibroblasts.

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