Obesity is the main determinant of insulin resistance more than the circulating pro-inflammatory cytokines levels in rheumatoid arthritis patients / A obesidade é um determinante da resistência à insulina mais importante do que os níveis circulantes de citocinas pró-inflamatórias em pacientes com artrite reumatoide

ABSTRACT Background: Systemic blockade of TNF-α in Rheumatoid arthritis with insulin resistance seems to produce more improvement in insulin sensitivity in normal weight patients with Rheumatoid arthritis than in obese patients with Rheumatoid arthritis, suggesting that systemic-inflammation and obesity are independent risk factors for insulin resistance in Rheumatoid arthritis patients. Objectives: To evaluate the insulin resistance in: normal weight patients with Rheumatoid arthritis, overweight patients with Rheumatoid arthritis, obese Rheumatoid arthritis patients, and matched control subjects with normal weight and obesity; and its association with major cytokines involved in the pathogenesis of the disease. Methods: Assessments included: body mass index, insulin resistance by Homeostasis Model Assessment, ELISA method, and enzymatic colorimetric assay. Results: Outstanding results from these studies include: (1) In Rheumatoid arthritis patients, insulin resistance was well correlated with body mass index, but not with levels of serum cytokines. In fact, levels of cytokines were similar in all Rheumatoid arthritis patients, regardless of being obese, overweight or normal weight (2) Insulin resistance was significantly higher in Rheumatoid arthritis with normal weight than in normal weight (3) No significant difference was observed between insulin resistances of Rheumatoid arthritis with obesity and obesity (4) As expected, levels of circulating cytokines were significantly higher in Rheumatoid arthritis patients than in obesity. Conclusions: Obesity appears to be a dominant condition above inflammation to produce IR in RA patients. The dissociation of the inflammation and obesity components to produce IR suggests the need of an independent therapeutic strategy in obese patients with RA.

RESUMO Introdução: O bloqueio sistêmico do Fator de Necrose Tumoral-α (TNF-α) nos indivíduos com artrite reumatoide (AR) com resistência à insulina (RI) parece produzir mais melhoria na sensibilidade à insulina em pacientes com AR com peso normal do que em pacientes obesos com AR. Isso sugere que a inflamação sistêmica e a obesidade são fatores de risco independentes para a RI em pacientes com AR. Objetivos: Avaliar a resistência à insulina em pacientes com peso normal com AR (AR-PN), pacientes com sobrepeso com AR (AR-SP), pacientes com AR obesos (AR-OB) e indivíduos controle com peso normal (PN) e obesidade (OB) pareados; e a associação com as principais citocinas envolvidas na patogênese da doença. Métodos: As avaliações incluíram: índice de massa corporal (IMC), resistência à insulina com o modelo de avaliação da homeostase (Homa-IR), método Elisa e ensaio colorimétrico enzimático. Resultados: Os resultados marcantes do presente estudo incluíram: (1) Em pacientes com AR, a RI estava bem correlacionada com o Índice de Massa Corporal (quanto maior o IMC, maior a RI), mas não com os níveis séricos de citocinas. Na verdade, os níveis de citocinas eram semelhantes em todos os pacientes com AR, independentemente de serem obesos, com sobrepeso ou peso normal. (2) A RI foi significativamente maior no grupo AR-PN do que no grupo PN. (3) Não houve diferença estatisticamente significativa entre a RI de pacientes AR-OB e OB. (4) Como esperado, os níveis circulantes de citocinas foram significativamente maiores em pacientes com AR do que em OB. Conclusões: A obesidade parece ser uma condição mais importante do que a inflamação em produzir RI em pacientes com AR. A dissociação dos componentes da inflamação e da obesidade na produção de RI sugere a necessidade de uma estratégia terapêutica independente em pacientes obesos com AR.

Obesity is the main determinant of insulin resistance more than the circulating pro-inflammatory cytokines levels in rheumatoid arthritis patients.

BACKGROUND: Systemic blockade of TNF-α in Rheumatoid arthritis with insulin resistance seems to produce more improvement in insulin sensitivity in normal weight patients with Rheumatoid arthritis than in obese patients with Rheumatoid arthritis, suggesting that systemic-inflammation and obesity are independent risk factors for insulin resistance in Rheumatoid arthritis patients. OBJECTIVES: To evaluate the insulin resistance in: normal weight patients with Rheumatoid arthritis, overweight patients with Rheumatoid arthritis, obese Rheumatoid arthritis patients, and matched control subjects with normal weight and obesity; and its association with major cytokines involved in the pathogenesis of the disease. METHODS: Assessments included: body mass index, insulin resistance by Homeostasis Model Assessment, ELISA method, and enzymatic colorimetric assay. RESULTS: Outstanding results from these studies include: (1) In Rheumatoid arthritis patients, insulin resistance was well correlated with body mass index, but not with levels of serum cytokines. In fact, levels of cytokines were similar in all Rheumatoid arthritis patients, regardless of being obese, overweight or normal weight (2) Insulin resistance was significantly higher in Rheumatoid arthritis with normal weight than in normal weight (3) No significant difference was observed between insulin resistances of Rheumatoid arthritis with obesity and obesity (4) As expected, levels of circulating cytokines were significantly higher in Rheumatoid arthritis patients than in obesity. CONCLUSIONS: Obesity appears to be a dominant condition above inflammation to produce IR in RA patients. The dissociation of the inflammation and obesity components to produce IR suggests the need of an independent therapeutic strategy in obese patients with RA.

Anti-inflammatory, free radical scavenging and alpha-glucosidase inhibitory activities of Hamelia patens and its chemical constituents.

Context Hamelia patens Jacq. (Rubiaceae) is traditionally used to treat wounds, inflammation and diabetes. However, there is still a lack of scientific evidence to support these applications. Objective The objective of this study is to evaluate the anti-inflammatory, antioxidant and antidiabetic activities of Hamelia patens, and identify its bioactive compounds. Materials and methods Four extracts were obtained by maceration and liquid-liquid extraction: HEX, DCM-EtOAc, MeOH-EtOAc and MeOH-Aq. The anti-inflammatory effect was evaluated orally on rat paw carrageenan-induced oedema over 6 h (50, 200 and 500 mg/kg), and topically in mouse ear oedema induced by 12-tetradecanoylphorbol-13-acetate (TPA) after 4 h (0.5 and 1 mg/ear). We also evaluated myeloperoxidase levels in ear tissue, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging ability, and in vitro α-glucosidase inhibition. The chemical compounds were separated by column chromatography and identified by spectroscopic analysis. Results We found that the oral administration of the HEX extract at 500 and 200 mg/kg significantly decreased the carrageenan-induced inflammation after 1 and 3 h, respectively. The MeOH-EtOAc extract significantly inhibited myeloperoxidase activity (83.5%), followed by the DCM-EtOAc extract (76%), ß-sitosterol/stigmasterol (72.7%) and the HEX extract (55%), which significantly decreased oedema induced by TPA at both doses, giving a similar effect to indomethacin. We also found that the MeOH-EtOAc, MeOH-Aq and DCM-EtOAc extracts showed good DPPH scavenging activity (IC50 values of 18.6, 93.9 and 158.2 µg/mL, respectively). The HEX extract showed the lowest α-glucosidase inhibition (an IC50 value of 26.07 µg/mL), followed by the MeOH-EtOAc extract (an IC50 value of 30.18 µg/mL), ß-sitosterol/stigmasterol (IC50 34.6 µg/mL) and compound A ((6E,10E,14E,18E)-2,6,10,14,18,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene, an IC50 value of 114.6 µg/mL), which were isolated for the first time from Hamelia patens. Discussion and conclusion Hamelia patens possesses anti-inflammatory, antioxidant and α-glucosidase inhibitory activities, which support its traditional use. These effects can be attributed to the identified compounds.

Regulatory T cells in patients with systemic lupus erythematosus.

Regulatory T cells have an important role in the control of self-reactivity, and in the pathogenesis of autoimmune inflammatory conditions. The aim of this work was to perform a quantitative and functional analysis of regulatory T cells in patients with systemic lupus erythematosus (SLE). We studied twenty-three patients with SLE (19 active, 4 inactive), and twenty-seven healthy subjects as well as fifteen patients with rheumatoid arthritis (RA). The following cell subsets were analyzed in peripheral blood mononuclear cells by flow cytometry: CD4+CD25+, CD4+CD25(bright), CD4+Foxp3+ (Treg cells), CD8+CD28- (Ts cells), CD4+IL-10+ (Tr1 cells), and CD4+TGF-beta+ (Th3 cells). In addition, the in vitro suppressive activity of CD4+CD25+ lymphocytes was tested. We found no significant differences in the levels of all regulatory cell subsets studied in SLE patients compared to controls and RA patients. However, a defective regulatory function of CD4+CD25+T cells was observed in a significant fraction (31%) of patients with SLE. Our data indicate that although approximately one third of patients with SLE show an abnormal immunosuppressive function of Treg lymphocytes, their levels of the different regulatory T cell subsets in peripheral blood are not significantly different from those found in controls.

Regulatory T cells in human autoimmune thyroid disease.

CONTEXT: T regulatory cells have a key role in the pathogenesis of autoimmune diseases in different animal models. However, less information is available regarding these cells in human autoimmune thyroid diseases (AITD). OBJECTIVE: The objective of the study was to analyze different regulatory T cell subsets in patients with AITD. DESIGN: We studied by flow cytometry and immunohistochemistry different T regulatory cell subsets in peripheral blood mononuclear cells (PBMCs) and thyroid cell infiltrates from 20 patients with AITD. In addition, the function of T(REG) lymphocytes was assessed by cell proliferation assays. Finally, TGF-beta mRNA in thyroid tissue and its in vitro synthesis by thyroid mononuclear cells (TMCs) was determined by RNase protection assay and quantitative PCR. RESULTS: PBMCs from AITD patients showed an increased percent of CD4+ lymphocytes expressing glucocorticoid-induced TNF receptor (GITR), Foxp3, IL-10, TGF-beta, and CD69 as well as CD69+CD25(bright), CD69+TGF-beta, and CD69+IL-10+ cells, compared with controls. TMCs from these patients showed an increased proportion of CD4+GITR+, CD4+CD69+, and CD69+ cells expressing CD25(bright), GITR, and Foxp3, compared with autologous PBMCs. Furthermore, a prominent infiltration of thyroid tissue by CD69+, CD25+, and GITR+ cells, with moderate levels of Foxp3+ lymphocytes, was observed. The suppressive function of peripheral blood T(REG) cells was defective in AITD patients. Finally, increased levels of TGF-beta mRNA were found in thyroid tissue, and thyroid cell infiltrates synthesized in vitro significant levels of TGF-beta upon stimulation through CD69. CONCLUSIONS: Although T regulatory cells are abundant in inflamed thyroid tissue, they are apparently unable, in most cases, to downmodulate the autoimmune response and the tissue damage seen in AITD.

Control of lymphocyte shape and the chemotactic response by the GTP exchange factor Vav.

Rho GTPases control many facets of cell polarity and migration; namely, the reorganization of the cellular cytoskeleton to extracellular stimuli. Rho GTPases are activated by GTP exchange factors (GEFs), which induce guanosine diphosphate (GDP) release and the stabilization of the nucleotide-free state. Thus, the role of GEFs in the regulation of the cellular response to extracellular cues during cell migration is a critical step of this process. In this report, we have analyzed the activation and subcellular localization of the hematopoietic GEF Vav in human peripheral blood lymphocytes stimulated with the chemokine stromal cell-derived factor-1 (SDF-1alpha). We show a robust activation of Vav and its redistribution to motility-associated subcellular structures, and we provide biochemical evidence of the recruitment of Vav to the membrane of SDF-1alpha-activated human lymphocytes, where it transiently interacts with the SDF-1alpha receptor CXCR4. Overexpression of a dominant negative form of Vav abolished lymphocyte polarization, actin polymerization, and migration. SDF-1alpha-mediated cell polarization and migration also were impaired by overexpression of an active, oncogenic Vav, although the mechanism appears to be different. Together, our data postulate a pivotal role for Vav in the transmission of the migratory signal through the chemokine receptor CXCR4.

Rolipram inhibits polarization and migration of human T lymphocytes.

Phosphodiesterase inhibitors possess anti-inflammatory and immunomodulatory properties and seem to have a great potential in the treatment of inflammatory skin diseases; however, an overall study on the effects of specific phosphodiesterase inhibitors, such as rolipram on the processes involved in the extravasation of lymphoid cells has not been performed. In this work we have assessed the effect of rolipram on the adhesion, polarization, and migration of normal human T lymphocytes. We found that low concentrations of rolipram were able to inhibit significantly the adhesion of T cells to the beta1 and beta2 integrin ligands vascular cell adhesion molecule-1 and intercellular adhesion molecule-1. Rolipram also interfered with the activation of integrins, and significantly inhibited the homotypic aggregation of T lymphocytes induced by anti-beta1 and anti-alpha4 integrin chain monoclonal antibodies. In addition, rolipram had a downregulatory effect on the activation of T cells, and significantly diminished the expression of the activation antigens CD69, CD25, and CD98 induced by phytohemagglutinin. Finally, this drug inhibited the polarization and transendothelial migration of T lymphocytes induced by the chemokine CXCL12 (SDF-1) and the chemotactic cytokine interleukin-15. The results indicate that rolipram, at low concentrations, exerts an important anti-inflammatory and immunomodulatory effect, and suggest that this selective phosphodiesterase inhibitor may be an effective tool for the therapy of immune-mediated diseases.