Interleukin-6 treatment enhances human monocyte permissiveness for Paracoccidioides brasiliensis growth by modulating cytokine production

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of Maternal Hyperglycemia on IL-10 and TNF-alpha Production: The Relationship with Perinatal Outcomes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemically induced immunotoxicity in a medium-term multiorgan bioassay for carcinogenesis with Wistar rats

A variety of chemicals can adversely affect the immune system and influence tumor development. The modifying potential of chemical carcinogens on the lymphoid organs and cytokine production of rats submitted to a medium-term initiation-promotion bioassay for carcinogenesis was investigated. Male Wistar rats were sequentially initiated with N-nitrosodiethylamine (DEN), N-methyl-N-nitrosourea (MNU), N-butyl-N-(4hydroxybutyl)nitrosamine (BBN), dihydroxy-di-n-propylnitrosamine (DHPN), and 1,2-dimethylhydrazine (DMH) during 4 weeks. Two initiated groups received phenobarbital (PB) or 2-acetyl amino fluorene (2-AAF) for 25 weeks and two noninitiated groups received only PB or 2-AAF. A nontreated group was used as control. Lymphohematopoietic organs, liver, kidneys, lung, intestines, and Zymbal's gland were removed for histological analysis. Interleukin (IL)-2, IL-12, interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), IL-10, and transforming growth factor betal (TGF-beta1) levels were determined by ELISA in spleen cell culture supernatants. At the fourth week, exposure to the initiating carcinogens resulted in cell depletion of the thymus, spleen and bone marrow, and impairment of IL-2, IL-12, and IFN-gamma production. However, at the 30th week, no important alterations were observed both in lymphoid organs and cytokine production in the different groups. The results indicate that the initiating carcinogens used in the present protocol exert toxic effects on the lymphoid organs and affect the production of cytokines at the initiation step of carcinogenesis. This early and reversible depression of the immune surveillance may contribute to the survival of initiated cells facilitating the development of future neoplasia. (C) 2003 Elsevier B.V. All rights reserved.

Sarcopenia da caquexia reumatoide: conceituação, mecanismos, consequências clínicas e tratamentos possíveis

A caquexia relacionada à artrite reumatoide é conceituada como perda involuntária de massa magra, predominantemente de músculo esquelético, que também ocorre em vísceras e sistema imune, com massa gorda estável ou um pouco elevada e com pequena ou nenhuma perda de peso. A causa é multifatorial, incluindo a produção acentuada de citocinas, principalmente TNF± e IL-1², diminuição da ação periférica da insulina e pouca atividade física. A caquexia se faz presente em doentes com AR ativa ou mesmo inativa. Neste artigo discutem-se aspectos relacionados à patogenia, implicações clínicas e possíveis opções terapêuticas.

Endotoxemia por lipopolissacarídeo de Escherichia coli, em eqüinos: efeitos de antiinflamatórios nas concentrações sérica e peritoneal do fator de necrose tumoral alfa (TNF-alfa)

Avaliou-se a inibição da produção do fator de necrose tumoral alfa (TNF-alfa) devido ao pré-tratamento com antiinflamatório esteroidal (dexametasona) e não esteroidal (diclofenaco sódico) em eqüinos com endotoxemia induzida experimentalmente. Foram utilizados 15 cavalos machos não castrados, distribuídos em três grupos de cinco animais: controle (C), diclofenaco sódico (DS) e dexametasona (DM). A endotoxemia subletal foi induzida pela infusão intravenosa (IV) de 0,1mg/kg/pv de lipopolissacarídeo (LPS) de Escherichia coli 055:B5, administrado em 250ml de solução estéril de cloreto de sódio a 0,9%, durante 15min. Os cavalos do grupo-controle foram tratados com solução de cloreto de sódio a 9% IV. Nos animais do grupo DS, administraram-se, por via oral, 2,2mg/kg de diclofenaco sódico e, nos do grupo DM, 1,1mg/kg de dexametasona IV, respectivamente, 60 e 30min antes da infusão da endotoxina. Mensurou-se, por meio de ensaio de toxicidade com células da linhagem L929, a concentração de TNF-alfa no soro e no líquido peritoneal às 0, 1¼, 3 e 6 horas após injeção do LPS. No grupo-controle, observou-se aumento significativo de TNF-alfa sérico, em relação ao valor basal e aos grupos DS e DM, 1,15 horas após a indução da endotoxemia. No líquido peritoneal, as concentrações observadas estavam abaixo daquelas da curva padrão de TNF-alfa, não havendo diferença entre os grupos (P>0,05).

Evaluation of TNF-alpha, IL-4, and IL-10 and parasite density in spleen and liver of L. (L.) chagasi naturally infected dogs

Dogs are the main domestic reservoirs of L. (L.) chagasi. Once in the vertebrate host, the parasite can cause visceral leishmaniasis, which can also be transmitted to humans. Cytokines are key elements of the host immune response against Leishmania spp. To investigate whether tumor necrosis factor (TNF)-alpha, interleukin (IL)-4 and IL-10 are associated with pattern infection in dogs, these cytokines were quantified in the spleen and liver of dogs naturally infected with L. (L.) chagasi, with or without clinical manifestations, and their levels were correlated with the parasite load verified in these organs. A total of 40 adult dogs naturally infected with L. (L.) chagasi were assessed, together with 12 uninfected control dogs. Samples from spleen and liver were used to determine the cytokine levels by capture ELISA and for quantifying parasite load by real-time PCR. Statistical analysis was performed using the minimum Chi square method and group means were compared using the Tukey test. TNF-alpha, IL-4 and IL-10 levels in infected dogs were higher than in control groups; the liver was the main cytokine-producing organ during infection. The level of splenic TNF-alpha showed correlation with parasite load and may represent an important marker for infection process evolution, with the participation of IL-10. These results may contribute to a clearer understanding of the immune response in dogs infected with L. (L.) chagasi, which may lead to the development of prophylactic or preventive measures for these animals.

Hypertension favors the inflammatory process in rats with experimentally induced periodontitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

MKK3/6-p38 MAPK signaling is required for IL-1 beta and TNF-alpha-induced RANKL expression in bone marrow stromal cells

Coupled bone turnover is directed by the expression of receptor-activated NF-kappa B ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG). Proinflammatory cytokines, such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) induce RANKL expression in bone marrow stromal cells. Here, we report that IL-1 beta and TNF-alpha-induced RANKL requires p38 mitogen-activating protein kinase (MAPK) pathway activation for maximal expression. Real-time PCR was used to assess the p38 contribution toward IL-1 beta and TNF-alpha-induced RANKL mRNA expression. Steady-state RANKL RNA levels were increased approximately 17-fold by IL-1 beta treatment and subsequently reduced similar to 70%-90% when p38 MAPK was inhibited with SB203580. RANKL mRNA stability data indicated that p38 MAPK did not alter the rate of mRNA decay in IL-1 beta-induced cells. Using a RANKL-luciferase cell line receptor containing a 120-kB segment of the 5' flanking region of the RANKL gene, reporter expression was stimulated 4-5-fold by IL-1 beta or TNF-alpha treatment. IL-1 beta-induced RANKL reporter expression was completely blocked with specific p38 inhibitors as well as dominant negative mutant constructs of MAPK kinase-3 and -6. In addition, blocking p38 signaling in bone marrow stromal cells partially inhibited IL-1 beta and TNF-alpha-induced osteoclastogenesis in vitro. Results from these studies indicate that p38 MAPK is a major signaling pathway involved in IL-1 beta and TNF-alpha-induced RANKL expression in bone marrow stromal cells.

Prostaglandin production by human gingival fibroblasts inhibited by triclosan in the presence of cetylpyridinium chloride

Background: the effect of triclosan plus the cationic detergent cetylpyridinium chloride (CPC) was evaluated for prostaglandin inhibition in human gingival fibroblasts. Since triclosan has previously been shown to inhibit proinflammatory cytokine induced prostaglandin E-2 (PGE(2)) production, we wanted to determine if triclosan, in the presence of CPC, could enhance these effects.Methods: Initial studies determined that both triclosan and CPC were cytotoxic to human gingival fibroblasts in concentrations exceeding 1.0 mu g/ml for either agent longer than 24 hours in a tissue culture. Therefore, subsequent studies measuring prostaglandin biosynthesis and cyclooxygenase (COX)-1 and COX-2 mRNA expression were performed in concentrations and times that did not significantly affect cell viability.Results: PGE2 biosynthesis was dose dependently inhibited by both triclosan and triclosan and CPC when challenged by tumor necrosis factor (TNF)-alpha or interleukin (IL)-1 beta. At pharmacologically relevant concentrations, triclosan and CPC inhibited ILAP-induced PGE(2) production to a greater extent than triclosan alone (P = 0.02). Moreover, enhanced COX-2 mRNA repression was observed with triclosan and CPC in comparison to triclosan alone in IL-1 beta and TNF-alpha stimulated cells. No effect on COX-I gene expression was observed. Further analysis of cell signaling mechanisms of triclosan and CPC indicates that nuclear factor-kappa B (NF-kappa B) and not p38 mitogen-activated protein kinase (MAPK) signaling may be impaired in the presence of triclosan and CPC.Conclusion: This study indicates that triclosan and CPC are more effective at inhibiting PGE(2) at the level of COX-2 gene regulation, and this combination may offer a potentially better anti -inflammatory agent in the treatment of inflammatory lesions in the oral cavity.

Potent anti-inflammatory effects of systemically administered curcumin modulate periodontal disease in vivo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Genetic Responses to Nanostructured Calcium-phosphate-coated Implants

Nanostructured calcium phosphate (CaP) has been histologically and biomechanically proven to enhance osseointegration of implants; however, conventional techniques were not sufficiently sensitive to capture its biological effects fully. Here, we compared the conventional removal torque (RTQ) evaluation and gene expression in tissues around nanostructured CaP-coated implants, using real-time RT-PCR, with those of uncoated implants, in a rabbit model. At 2 wks, RTQ values were significantly higher, alkaline phosphatase (ALP) expression was significantly higher, and runt-related transcription factor 2 and tumor necrosis factor-alpha expressions were significantly lower in the coated than in the uncoated implants. This indicates that inflammatory responses were suppressed and osteoprogenitor activity increased around the CaP-coated surface. At 4 wks, although RTQ values did not significantly differ between the 2 groups, ALP and osteocalcin (OCN) were significantly up-regulated in the coated group, indicating progressive mineralization of the bone around the implant. Moreover, an osteoclast marker, adenosine triphosphatase, which indicates acidification of the resorption lacunae, was significantly higher for the coated implants, suggesting gradual resorption of the CaP coating. This study reveals detailed genetic responses to nanostructured CaP-coated implants and provides evidence that the effect of nanotopography is significant during the osseointegration cascade.

Correlation between Clinical/Radiographic Features and Inflammatory Cytokine Networks Produced by Macrophages Stimulated with Endodontic Content

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental paracoccidioidomycosis of the Syrian hamster: fungicidal activity and production of inflammatory cytokines by macrophages

Phagocytic cells play an important role in nonspecific resistance to fungal infection by mediating an inflammatory response and by a direct fungicidal action. In this study, the functional activity of peritoneal macrophages obtained from hamsters experimentally infected with strain Pb18 of Paracoccidioides brasiliensis was evaluated during 16 weeks of infection. The results showed that macrophages had a higher spreading ability associated with increased production of tumor necrosis factor alpha (TNF-alpha) and enhanced fungicidal activity during the early periods of infection. TNF-alpha levels remained elevated during all periods studied, while low levels of interleukin-1 beta (IL-1 beta) were produced during the infection. A necrotic area with dead fungi was observed at the inoculation site and the infection disseminated only to liver and lymph nodes in a few animals. These results suggest that during the early stages of infection with P. brasiliensis, macrophage activation by the high levels of TNF-alpha limited fungal dissemination. In contrast, in the later stages of infection, high levels of TNF-alpha were observed while the fungicidal activity of macrophages was lower and the animals presented loss of vitality resulting in their death. These observations suggest a complex role of TNF-alpha in experimental paracoccidioidomycosis of Syrian hamsters, involving not only resistance but also pathogenesis.

Production of pro- and anti-inflammatory cytokines by monocytes from patients with paracoccidioidomycosis

Monocytes and macrophages can produce a large repertoire of cytokines and participate in the pathogenesis of granulomatous diseases. We investigated the production of pro- and anti-inflammatory cytokines by monocytes from patients with active paracoccidioidomycosis. Peripheral blood monocytes from 37 patients and 29 healthy controls were cultivated with or without 10 mug/ml of lipopolysaccharide (LPS) for 18 h at 37 degreesC, and the cytokine levels were determined in the culture supernatants by enzyme immunoassay. The results showed that the endogenous levels of tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta (IL-1beta), IL-6, IL-8, IL-10 and transforming growth factor beta detected in the supernatant of patient monocytes cultivated without stimulus were significantly higher than those produced by healthy controls. These data demonstrated that monocytes from patients with active paracoccidioidomycosis produce high levels of cytokines with both inflammatory and anti-inflammatory activities. However, patient monocytes produced significantly lower TNF-alpha and IL-6 levels in response to LPS when compared to normal subjects, suggesting an impairment in their capacity to produce these cytokines after LPS stimulation. Concentrations of IL-1beta, IL-8 and IL-10 in cultures stimulated with LPS were higher in patients than in controls. These results suggest that an imbalance in the production of pro- and anti-inflammatory cytokines might be associated with the pathogenesis of paracoccidioidomycosis. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.

Decreased production of TNF-alpha by lymph node cells indicates experimental autoimmune encephalomyelitis remission in Lewis rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)