Aspirin attenuates the anti-inflammatory effects of theophylline via inhibition of cAMP production in mice with non-eosinophilic asthma

Nonsteroidal Anti-Inflammatory Drugs and Experimental Chagas Disease: An Unsolved Question

Chagas disease is a parasitic disease caused by the protozoan Trypanosoma cruzi with an acute, detectable blood parasites phase and a chronic phase, in which the parasitemia is not observable, but cardiac and gastrointestinal consequences are possible. Mice are the principal host used in experimental Chagas disease but reproduce the human infection depending on the animal and parasite strain, besides dose and route of administration. Lipidic mediators are tremendously involved in the pathogenesis of T. cruzi infection, meaning the prostaglandins and thromboxane, which participate in the immunosuppression characteristic of the acute phase. Thus, the eicosanoids inhibition caused by the nonsteroidal anti-inflammatory drugs (NSAIDs) alters the dynamic of the disease in the experimental models, both in vitro and in vivo, which can explain the participation of the different mediators in infection. However, marked differences are founded in the various NSAIDs existing because of the varied routes blocked by the drugs. So, knowing the results in the experimental models of Chagas disease with or without the NSAIDs helps comprehend the pathogenesis of this infection, which still needs a better understanding.

Ligustrazine Inhibits Lung Phosphodiesterase Activity in a Rat Model of Allergic Asthma

Objectives

This study sought to examine whether ligustrazine was capable of inhibiting phosphodiesterase (PDE) activity and improving lung function in a rat model of asthma.

Methods

Rats were initially sensitized using ovalbumin (OVA) and then were challenged daily with aerosolized OVA beginning 14 days later (30 min/day) to generate a rat model of asthma. Changes in airway function following methacholine (MCh) injection were evaluated by monitoring lung resistance (R_L) and dynamic lung compliance (C_dyn) values using an AniRes2005 analytic system. In addition, serum IgE was measured via ELISA, while PDE expression was evaluated via qPCR and western blotting. Key Findings. Ligustrazine significantly impaired allergen-induced lung hyperresponsivity and inflammation in this asthma model system. Ligustrazine treatment was also associated with reduced expression of PDEs including PDE4 in the lungs of these rats.

Conclusions

Ligustrazine suppresses airway inflammation and bronchial hyperresponsivity in this rat model system, and these changes are associated with decreased PDE expression at the protein and mRNA levels.

Protective effects on ovalbumin-induced mouse asthma models and qualitative and quantitative analysis of multiple compounds in Gerberae Piloselloidis Herba

Gerberae Piloselloidis Herba is widely used to treat cough and asthma in China. However, its effects on allergic asthma as related to its chemical compositions have not been fully elucidated, and there is a scarcity of methods to determine multi-component contents for quality control. In this study, protective effects of Gerberae Piloselloidis Herba on ovalbumin-induced asthma models were investigated, while qualitative and quantitative analyses of multiple constituents in Gerberae Piloselloidis Herba were conducted by using an ultrahigh-performance liquid chromatography -Q Exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry and an ultrahigh-performance liquid chromatography -photodiode array detection. The results showed that Gerberae Piloselloidis Herba could significantly mitigate asthma symptoms, reduce eosinophils counts in the bronchoalveolar lavage fluid, as well as decrease IgE, IL-5 and IL-13 concentration, and inflammatory cellular infiltration in lung tissues. A total of 51 compounds were tentatively identified, in which the content of 10 representative compounds was determined in 24 batches of Gerberae Piloselloidis Herba by using an ultrahigh-performance liquid chromatography method with good linearity, precision, repeatability, accuracy and stability. This research presents a comprehensive strategy combining biological activity evaluation with chemical profiling, providing a useful and comprehensive reference for further application and quality control of Gerberae Piloselloidis Herba. This article is protected by copyright. All rights reserved.

Plants as Sources of Anti-Inflammatory Agents

Plants represent the main source of molecules for the development of new drugs, which intensifies the interest of transnational industries in searching for substances obtained from plant sources, especially since the vast majority of species have not yet been studied chemically or biologically, particularly concerning anti-inflammatory action. Anti-inflammatory drugs can interfere in the pathophysiological process of inflammation, to minimize tissue damage and provide greater comfort to the patient. Therefore, it is important to note that due to the existence of a large number of species available for research, the successful development of new naturally occurring anti-inflammatory drugs depends mainly on a multidisciplinary effort to find new molecules. Although many review articles have been published in this regard, the majority presented the subject from a limited regional perspective. Thus, the current article presents highlights from the published literature on plants as sources of anti-inflammatory agents.

Trypanosoma cruzi: Inhibition of infection of human monocytes by aspirin

Cell invasion by Trypanosoma cruzi and its intracellular replication are essential for progression of the parasite life cycle and development of Chagas disease. Prostaglandin E2 (PGE₂) and other eicosanoids potently modulate host response and contribute to Chagas disease progression. In this study, we evaluated the effect of aspirin (ASA), a non-selective cyclooxygenase (COX) inhibitor on the T. cruzi invasion and its influence on nitric oxide and cytokine production in human monocytes. The pretreatment of monocytes with ASA or SQ 22536 (adenylate-cyclase inhibitor) induced a marked inhibition of T. cruzi infection. On the other hand, the treatment of monocytes with SQ 22536 after ASA restored the invasiveness of T. cruzi. This reestablishment was associated with a decrease in nitric oxide and PGE₂ production, and also an increase of interleukin-10 and interleukin-12 by cells pre-treated with ASA. Altogether, these results reinforce the idea that the cyclooxygenase pathway plays a fundamental role in the process of parasite invasion in an in vitro model of T. cruzi infection.

Inhibition of cyclooxygenase-1 and cyclooxygenase-2 impairs Trypanosoma cruzi entry into cardiac cells and promotes differential modulation of the inflammatory response

The intracellular protozoan parasite Trypanosoma cruzi is the etiologic agent of Chagas disease, a serious disorder that affects millions of people in Latin America. Cell invasion by T. cruzi and its intracellular replication are essential to the parasite's life cycle and for the development of Chagas disease. Here, we present evidence suggesting the involvement of the host's cyclooxygenase (COX) enzymes during T. cruzi invasion. Pharmacological antagonists for COX-1 (aspirin) and COX-2 (celecoxib) caused marked inhibition of T. cruzi infection when rat cardiac cells were pretreated with these nonsteroidal anti-inflammatory drugs (NSAIDs) for 60 min at 37°C before inoculation. This inhibition was associated with an increase in the production of NO and interleukin-1β and decreased production of transforming growth factor β (TGF-β) by cells. Taken together, these results indicate that COX-1 more than COX-2 is involved in the regulation of anti-T. cruzi activity in cardiac cells, and they provide a better understanding of the influence of TGF-β-interfering therapies on the innate inflammatory response to T. cruzi infection and may represent a very pertinent target for new therapeutic treatments of Chagas disease.

Stereoselective activity of 2-(4-amino-3-chloro-5- trifluomethyl-phenyl)-2-tert-butylamino-ethanol hydrochloride to improve the pulmonary function in asthma

Asthma is a chronic airway disease that is characterized by significantly exacerbated bronchospasms and marked inflammation of the airways. Although the etiology of asthma remains to be determined, genetic predisposition is one of the factors involved. β₂-agonists compounds may serve as options for the treatment of bronchial asthma. The aim of the present study was to investigate the effects of 2-(4-amino-3-chloro-5-trifluomethyl-phenyl)-2-tert-butylamino-ethanol hydrochloride (SPFF) and its enantiomers with regard to improving asthmatic pulmonary function and selective binding to β₂-adrenergic receptor. The bronchoconstrictor action of histamine in guinea pigs was conducted and the results demonstrated that (-)SPFF and (±)SPFF could significantly inhibit the increase of bronchoconstriction induced by histamine, while (+)SPFF did not show an effect. Inflammatory mediator release from allergic lung tissues was determined and it was found that (±)SPFF showed the highest activity among all the tested compounds, while the efficacy of (-)SPFF was similar to that of (+)SPFF. SPFF and its enantiomers stimulated cyclic adenosine monophosphate (cAMP) production in the asthmatic lung tissues examined, showing that asthmatic lung tissues had a significant cAMP enhancement in response to (-)SPFF and (±)SPFF compared with (+)SPFF. Cardiac contractility of the right atria was assessed in the guinea pigs to establish the receptor selectivity of the compounds. The results indicated that all the compounds had high affinities to the β₂ receptor. In conclusion, with regards to asthmatic pulmonary function improvement, (-)SPFF was more efficient as compared to (+)SPFF, while no significant difference was observed for the receptor selectivity of (-)SPFF and (+)SPFF.

Aspirin metabolites are GPR35 agonists

Aspirin is widely used as an anti-inflammatory, anti-platelet, anti-pyretic, and cancer-preventive agent; however, the molecular mode of action is unlikely due entirely to the inhibition of cyclooxygenases. Here, we report the agonist activity of several aspirin metabolites at GPR35, a poorly characterized orphan G protein-coupled receptor. 2,3,5-Trihydroxybenzoic acid, an aspirin catabolite, was found to be the most potent GPR35 agonist among aspirin metabolites. Salicyluric acid, the main metabolite of aspirin, was also active. These results suggest that the GPR35 agonist activity of certain aspirin metabolites may contribute to the clinical features of aspirin.

Can β2-adrenoceptor agonists, anticholinergic drugs, and theophylline contribute to the control of pulmonary inflammation and emphysema in COPD?

Chronic obstructive pulmonary disease (COPD) has become a global epidemic disease with an increased morbidity and mortality in the world. Inflammatory process progresses and contributes to irreversible airflow limitation. However, there is no available therapy to better control the inflammatory progression and therefore to reduce the exacerbations and mortality. Thus, the development of efficient anti-inflammatory therapies is a priority for patients with COPD. β(2) -Adrenoceptor agonists and anticholinergic agents are widely used as first line drugs in management of COPD because of their efficient bronchodilator properties. At present, many studies in vitro and some data obtained in laboratory animals reveal the potential anti-inflammatory effects of these bronchodilators but their protective role against chronic inflammation and the development of emphysema in patients with COPD remains to be investigated. The anti-inflammatory effects of theophylline at low doses have also been identified. Beneficial interactions between glucocorticoids and bronchodilators have been reported, and signaling pathways explaining these synergistic effects begin to be understood, especially for theophylline. Recent data demonstrating interactions between anticholinergics with β(2) -adrenoceptor agonists aiming to better control the pulmonary inflammation and the development of emphysema in animal models of COPD justify the priority to investigate the interactive effects of a tritherapy associating corticoids with the two main categories of bronchodilators.

Alveolar macrophages modulate allergic inflammation in a murine model of asthma

The role of alveolar macrophages (AMs) in the pathogenesis of asthma is still unknown. The aim of the present study was to investigate the effects of AM in the murine model of asthma. AMs were selectively depleted by liposomes containing clodronate just before allergen challenges, and changes in inflammatory cells and cytokine concentrations in bronchoalveolar lavage (BAL) fluid were measured. AMs were then adoptively transferred to AM-depleted sensitized mice and changes were measured. Phenotypic changes in AMs were evaluated after in vitro allergen stimulation. AM-depletion after sensitization significantly increased the number of eosinophils and lymphocytes and the concentrations of IL-4, IL-5 and GM-CSF in BAL fluid. These changes were significantly ameliorated only by adoptive transfer of unsensitized AMs, not by sensitized AMs. In addition, in vitro allergen stimulation of AMs resulted in their gaining the ability to produce inflammatory cytokines, such as IL-1β, IL-6 and TNF-α, and losing the ability to suppress GM-CSF concentrations in BAL fluid. These findings suggested that AMs worked probably through GM-CSF-dependent mechanisms, although further confirmatory experiments are needed. Our results indicate that the role of AMs in the context of airway inflammation should be re-examined.