Study of the expression and regulation of the autocrine loop components of the cyclooxygenase pathway and their implication in aspirin exacerbated respiratory disease
[eng] Aspirin exacerbated respiratory disease (AERD) is a clinical syndrome characterized by the combination of nasal polyps (NPs), chronic hypertrophic eosinophilic sinusitis, asthma and severity to any medication that inhibits cyclooxygenase (COX)-1 enzymes, namely aspirin and other non-steroidal...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/102808 |
| Acceso en línea: | https://hdl.handle.net/2445/102808 http://hdl.handle.net/10803/396213 |
| Access Level: | acceso abierto |
| Palabra clave: | Malalties de l'aparell respiratori Antiinflamatoris no esteroïdals Respiratory organs diseases Nonsteroidal anti-inflammatory agents |
| Sumario: | [eng] Aspirin exacerbated respiratory disease (AERD) is a clinical syndrome characterized by the combination of nasal polyps (NPs), chronic hypertrophic eosinophilic sinusitis, asthma and severity to any medication that inhibits cyclooxygenase (COX)-1 enzymes, namely aspirin and other non-steroidal anti-inflammatory drugs. AERD is characterized by intense inflammation of the respiratory mucosa, with large number of activated tissue eosinophils, mast cells, monocytes, and neutrophils. The persistent inflammation likely contributes to the recurrent development of severe nasal polyposis. The pathogenesis of AERD is not fully understood and many questions remain unsolved. However, several studies have reported that the pathogenic mechanisms of this condition may be due, at least in part, to a marked imbalance in eicosanoid metabolism, possibly increasing and perpetuating the process of inflammation. A central feature of AERD is its association with a profound overproduction and overresponsiveness to cysteinyl leukotrienes (cys-LTs) occurring concomitantly with a marked underproduction and underresponsiveness to prostaglandin (PG) E2, which result in a disproportion between pro-inflammatory and anti-inflammatory mediators. The downregulation of PG pathways impedes its mediators to participate in the attenuation of pro-inflammatory responses. Recent studies have demonstrated that the pattern of cytokine expression could differentiate patients with AERD and patients with asthma or eosinophilic sinusitis who tolerate aspirin. We hypothesized that the characteristics of the inflammatory airway milieu (cytokine profile) in AERD is responsible for the deficient expression of EP2 , modifying its capacity to respond to PGE2, resulting in an altered regulation of the autocrine positive loop of the COX pathway that contributes to the exacerbated inflammation and remodeling processes usually present in AERD. In summary, this study provides evidence supporting the hypothesis that the inflammatory environment in the airways of patients with AERD induces alterations in the expression of EP2. This anomaly alters the induction of interleukin-1 receptor type I (IL-1RI), the main factor receptor responsible for the activation of COX-2 by interleukin (IL)-1β, which, in turn, results in a low production of PGE2 which, associated with the low expression of the EP2 receptor, alters the autocrine feedback loop that regulates the COX pathway. The EP2 receptor plays a central role in the alteration of PGE2 synthesis, since its reestablishment can recover the normal function of the autocrine loop and thereby normalizing the expression and function of all the components that constitute it (IL-1RI, COX-2, microsomal PGE synthase-1 (mPGES-1) and PGE2). The decrease in the synthesis of PGE2 may contribute to the perpetuation of the eosinophilic inflammation and remodeling processes in the airways of patients who suffer from AERD. |
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