Sophie Molet

IL‐11 and IL‐17 expression in nasal polyps: Relationship to collagen deposition and suppression by intranasal fluticasone propionate

Objectives/Hypothesis: Chronic hyperplastic sinusitis (CHS) with nasal polyps (NP) is characterized by extensive mucosal thickening, goblet cell hyperplasia, and subepithelial fibrosis. These features are described to be part of remodeling in the lower airways. The cytokines interleukin (IL)‐11 and IL‐17 are believed to play a role in lower airway remodeling, but there has been very little work so far examining these cytokines and their relationship to fibrosis in CHS/NP. The aims of this study were to examine the deposition of collagens types I, III, and V in CHS/NP, evaluate the relationship of collagen deposition to expression of IL‐11 and IL‐17, and to examine the effect of treatment with intranasal fluticasone on these features. Study Design: Sixteen subjects were included in this double‐blind, placebo‐controlled study. NP biopsies were obtained at the baseline and after 4 weeks of treatment with intranasal fluticasone propionate (FP, Flonase) or placebo. Normal control middle turbinate biopsies from eight nonallergic subjects without sinusitis were used as a control for cytokine and collagen expression. Methods: Tissues were assessed for deposition of collagen types I, III, and V using immunocytochemistry. The expression of the cytokines IL‐11 and IL‐17 was examined by immunostaining or in situ hybridization. The pre‐ to posttreatment results were analyzed using paired t test, and the magnitude of changes were estimated using one‐way analysis of variance (ANOVA) statistical test followed by least significance difference post hoc comparisons of means. Results: Compared with normal control nasal turbinate tissues, collagen types I, III, and V were increased in all NP tissues, with a predominance of types III and V. Collagen deposition was most abundant in the submucosal connective tissue and in the basement membrane zone. FP treatment had no significant effect on deposition of any collagen type. Expression of IL‐11 and IL‐17 was also greatly increased in NP compared with control nasal turbinate tissues. IL‐11 expression was observed in both inflammatory cells and the epithelium, whereas IL‐17 expression was primarily associated with inflammatory cells. In the pretreatment NP, a correlation was found between the presence of IL‐11 and collagen type I (r = 0.59, P = .02) and also between IL‐17 and both CD4+ and CD8+ T lymphocytes (r = 0.52, P = .05; r = 0.60, P = .02, respectively). Treatment with FP significantly reduced IL‐11 expression in subepithelial inflammatory cells and in the epithelial compartment. In contrast, although IL‐17 expression was reduced by FP, this effect did not reach statistical significance. Conclusion: NP manifest an increased expression of collagen types III, V, and I and an increase in profibotic cytokines IL‐11 and IL‐17. A correlation exists between deposition of collagen type I and expression of IL‐11, suggesting a possible role for IL‐11 in NP remodeling. Collagen deposition was not reversed by FP treatment, whereas IL‐11 expression was suppressed. These results are consistent with a partial insensitivity of NP to FP treatment but also suggest that longer‐term treatment or perhaps earlier intervention with FP might reduce proinflammatory cytokine signals and ultimately have a beneficial effect in preventing airway remodeling in NP.

Montelukast, a leukotriene receptor antagonist, inhibits the late airway response to antigen, airway eosinophilia, and IL-5–expressing cells in Brown Norway rats

BACKGROUND Asthma is characterized by airflow obstruction, inflammatory cell infiltration, and the synthesis of mediators, such as T(H2) cytokines and leukotrienes, in the airways. Cysteinyl leukotriene (cysLT) receptor antagonists have recently been associated with clinical improvement of asthma and reduced airway inflammation. Whether the beneficial effects of cysLT antagonists are mediated through the modulation of cytokine expression has not been determined. OBJECTIVE The aim of the study was to determine the presence of eosinophils and IL-5 messenger (m)RNA(+) cells within the lungs of antigen-challenged Brown Norway rats after treatment with the cysLT(1) receptor antagonist montelukast (MK). METHODS Ovalbumin-sensitized Brown Norway rats were treated with either MK or saline before ovalbumin challenge. Pulmonary mechanics were monitored for 8 hours. Subsequently, immunocytochemistry and in situ hybridization were used to examine bronchoalveolar lavage (BAL) fluid and lung tissue for cells expressing major basic protein (eosinophils) and IL-5 mRNA, respectively. Simultaneous in situ hybridization and immunocytochemistry was used to phenotype the cells expressing mRNA encoding IL-5. RESULTS Animals treated with MK had significantly lower lung resistance and fewer eosinophils and IL-5 mRNA(+) cells within BAL fluid and lung tissue compared with that found in saline-treated animals. Colocalizaton studies revealed that the majority of IL-5 mRNA(+) cells were T cells and that the number of IL-5 mRNA(+)/CD3(+) or IL-5 mRNA(+)/major basic protein(+) cells were significantly less within BAL from animals treated with MK than from those treated with saline. CONCLUSIONS These results indicate that the cysLT(1) receptor antagonist MK can diminish the pulmonary response to antigen, tissue eosinophilia, and the number of cells expressing IL-5 mRNA, suggesting that leukotrienes may also regulate the allergic response through the modulation of inflammation and cytokine synthesis.

Chemokine- and cytokine-induced expression of endothelin 1 and endothelin-converting enzyme 1 in endothelial cells

BACKGROUND Endothelin 1 (ET-1) is a product of endothelial and many other cell types that possesses a wide range of actions, including vasoconstriction, bronchoconstriction, and mitogenic activity on smooth muscle cells and fibroblasts. ET-1 release and expression is induced in several disease conditions associated with inflammation and cellular injury. OBJECTIVE The purpose of this study is to determine the effects of alpha-chemokines (IL-8 and melanoma growth-stimulating activator), beta-chemokines (monocyte chemotactic protein 1, macrophage inflammatory protein 1alpha [MIP-1alpha], MIP-1beta, and RANTES), and proinflammatory cytokines (IL-1beta, TNF-alpha, and IFN-gamma) on the expression of both ET-1 and endothelin-converting enzyme 1 (ECE-1) by human umbilical vein endothelial cells. METHODS Subconfluent monolayers of human umbilical vein endothelial cells were incubated with each chemokine individually for 24 hours or with a mixture (cytomix) of TNF-alpha, IL-1beta, and IFN-gamma for 6 and 24 hours. RESULTS Incubation with the alpha-chemokines melanoma growth-stimulating activity and IL-8 did not significantly increase ET-1 and ECE-1 messenger (m)RNA expression and had no effect on ET-1 release. Monocyte chemotactic protein 1 exerted the most potent increase in ET-1 and ECE-1 mRNA and ET-1 release among all chemokines studied (P <.05). MIP-1alpha and RANTES exerted a moderate, but significant, increase on the ET system (P <.05). The cytomix resulted in a significant increase in ET-1 and ECE-1 mRNA expression (P <.05). CONCLUSION These data demonstrate that, like cytokines, chemokines can induce endothelial ET-1 and ECE-1 in vitro and suggest a possible role for these inflammatory mediators in the induction of the ET system in inflammatory and vascular diseases.

Adoptively transferred late allergic response is inhibited by IL-4, but not IL-5, antisense oligonucleotide

BACKGROUND We have shown previously that the late airways response (LAR) can be transferred by ovalbumin-primed CD4(+) T lymphocytes in Brown Norway rats. This response is associated with an increase of eosinophils and high expression of TH2 cytokines (IL-4 and IL-5) in bronchoalveolar lavage (BAL) fluid. OBJECTIVE In this study we hypothesized that the inhibition of IL-4 or IL-5 production in the CD4(+) cells transferred to a naive animal could decrease the LAR and prevent airway eosinophilia in response to antigen challenge. METHODS CD4(+) cells, purified from the cervical lymph nodes of ovalbumin-sensitized rats, were maintained in culture for 6 hours with medium alone or with 10 microgram/mL IL-4 antisense (AS), IL-5 AS, or control AS oligodeoxynucleotide. Then the cells were administrated intraperitoneally to naive rats, which were challenged 2 days later by a 5% ovalbumin aerosol. The lung resistance was measured for 8 hours, and then BAL was performed. Cytospin preparations from BAL cells were assessed for the presence of eosinophils by immunocytochemistry for major basic protein and for IL-4, IL-5, and IFN-gamma expression. RESULTS In rats injected with IL-4 AS-treated T cells, LAR, eosinophils, and IL-4 and IL-5 expression were significantly decreased compared with the other groups. Only IL-5 expression in BAL fluid was slightly decreased consequent to the transfer of IL-5 AS-treated T cells. CONCLUSION This study demonstrates that, in the CD4(+) T cell-driven LAR, the early production of IL-4, but not IL-5, by the transferred CD4(+) cells is essential for the development of the LAR.

Modulation of cell adhesion molecules on human endothelial cells by eosinophil-derived mediators.

Mechanisms that allow a selective eosinophil emigration in different eosinophilic lung diseases remain poorly understood. In this study, we tested the hypothesis that eosinophils might participate in their own recruitment, particularly through adhesion molecule expression on human endothelial cells (EC). Blood eosinophils from donors with blood eosinophilia were purified and maintained in culture medium for 1 and 18 h. The expression of ICAM‐1, E‐selectin, and VCAM‐1 on human umbilical vein endothelial cells (HUVEC) was evaluated by ELISA and flow cytometry analysis after addition of eosinophil supernatants. Eosinophil supernatants collected after 1 h induced a weak increase of CAM expression on HUVEC. In contrast, supernatants from eosinophils cultured for 18 h considerably amplified ICAM‐1, E‐selectin, and VCAM‐1 expression on the surface of EC. These levels of CAM expression (in optical density determined by ELISA) were about two‐ or threefold more important than those obtained with eosinophil supernatants collected after a 1‐h culture. The characterization of the implicated molecules showed that anti‐IL‐1β antibodies significantly inhibited ICAM‐1, E‐selectin, and VCAM‐1 expression, whereas anti‐TNF‐α antibodies only induced a moderate inhibition. Our data support the hypothesis that eosinophils, through the release of at least IL‐1β and TNF‐α, might participate in the amplification of the inflammatory reaction by activating the vascular endothelium. J. Leukoc. Biol. 63: 351–358; 1998.

EFFECTS OF CORTICOSTEROIDS ON ASTHMA PATHOLOGY

Initial information on asthma pathology was based on macroscopic examination of lungs obtained from patients who died of asthma attacks. During autopsy, the lungs appear to be overdistended and fail to deflate. The lungs are usually edematous and congested. The large and small airways are occluded by mucous plugs (now called eosinophil plugs), and their walls are significantly thickened. Dunnill described the pathological changes associated with status asthmaticus and showed that there is mucous obstruction, marked increase in goblet cells, and luminal mucus in peripheral airways. 42 Fiberoptic bronchoscopy now makes it possible to obtain bronchoalveolar lavages (BAL) and bronchial biopsies from patients with mild and moderate asthma and is a useful tool in monitoring disease activity and response to various treatments. During the last few years a large number of studies using these techniques have furthered the understanding of asthma pathology and pathogenesis. Histopathological changes associated with asthma include epithelial changes, such as shedding and desquamation; goblet cell hyperplasia; submucosal gland hypertrophy; thickening of the basement membrane (subepithelial fibrosis); inflammatory cell infiltration; hyperplasia and hypertrophy of the bronchial smooth muscle; and vascular changes. Corticosteroids (CSs) are the most effective drugs in the treatment of asthma. They cause marked improvement in airway inflammation and lung function. The mechanisms by which CSs resolve the inflammatory process in asthma, especially at the molecular level, are better, although still not fully, understood. This article focuses on the effects of CSs on the structural changes of the lungs in asthmatic patients and discusses possible mechanisms for these effects.