Lipid Mediators in Aspirin-Exacerbated Respiratory Disease

Management of Aspirin-Exacerbated Respiratory Disease: What Does the Future Hold?

Aspirin-exacerbated respiratory disease (AERD) is a subtype of chronic rhinosinusitis with polyps (CRSwNP) and asthma with higher recurrence of nasal polyps after surgery and severe asthma. Patients with CRSwNP and asthma should be screened for AERD by detailed history of aspirin/nonsteroidal anti-inflammatory drug reactions and review of medications that may mask aspirin reaction or directly by aspirin challenge. Treatment of AERD may require more intensive therapy, including endoscopic sinus surgery, daily aspirin therapy, leukotriene modifiers, or biologics.

Pathomechanisms of AERD—Recent Advances

The pathomechanisms behind NSAID-exacerbated respiratory disease are complex and still largely unknown. They are presumed to involve genetic predisposition and environmental triggers that lead to dysregulation of fatty acid and lipid metabolism, altered cellular interactions involving transmetabolism, and continuous and chronic inflammation in the respiratory track. Here, we go through the recent advances on the topic and sum up the current understanding of the background of this illness that broadly effects the patients' lives.

The Biology of Prostaglandins and Their Role as a Target for Allergic Airway Disease Therapy

Prostaglandins (PGs) are a family of lipid compounds that are derived from arachidonic acid via the cyclooxygenase pathway, and consist of PGD₂, PGI₂, PGE₂, PGF₂, and thromboxane B₂. PGs signal through G-protein coupled receptors, and individual PGs affect allergic inflammation through different mechanisms according to the receptors with which they are associated. In this review article, we have focused on the metabolism of the cyclooxygenase pathway, and the distinct biological effect of each PG type on various cell types involved in allergic airway diseases, including asthma, allergic rhinitis, nasal polyposis, and aspirin-exacerbated respiratory disease.

A current view of G protein-coupled receptor - mediated signaling in pulmonary hypertension: finding opportunities for therapeutic intervention

Pathological vascular remodeling is observed in various cardiovascular diseases including pulmonary hypertension (PH), a disease of unknown etiology that has been characterized by pulmonary artery vasoconstriction, right ventricular hypertrophy, vascular inflammation, and abnormal angiogenesis in pulmonary circulation. G protein-coupled receptors (GPCRs) are the largest family in the genome and widely expressed in cardiovascular system. They regulate all aspects of PH pathophysiology and represent therapeutic targets. We overview GPCRs function in vasoconstriction, vasodilation, vascular inflammation-driven remodeling and describe signaling cross talk between GPCR, inflammatory cytokines, and growth factors. Overall, the goal of this review is to emphasize the importance of GPCRs as critical signal transducers and targets for drug development in PH.

Effects of nonselective and selective cyclooxygenase inhibitors on the contractions of isolated bronchial smooth muscle in the horse

We evaluated the effects of nonselective cyclooxygenase (COX)-1/COX-2 inhibitors (acetylsalicylic acid, indomethacin, ibuprofen, flunixin meglumine, phenylbutazone), preferential COX-2 inhibitors (diclofenac, meloxicam, carprofen), selective COX-1 inhibitor (SC-560), and selective COX-2 inhibitors (celecoxib, firocoxib, parecoxib) on the contractions of isolated bronchi induced by electrical field stimulation (EFS). Bronchial rings, obtained from lungs of slaughtered horses, were put in isolated organ baths, and the mechanical activity was measured by means of isotonic transducers. Electrical Field Stimulation was applied to the preparations, and the effects of drugs on the amplitude of evoked contractions were measured. Nonselective COX inhibitors did not modify EFS-induced contractions to a relevant degree, except indomethacin which caused a concentration-dependent decrease of the contraction amplitude. Conversely, preferential COX-2 inhibitors enhanced the contractions in a concentration-related fashion, whilst the selective COX-1 inhibitor reduced them. Among selective COX-2 inhibitors, parecoxib increased EFS-evoked contractions whereas celecoxib and firocoxib were ineffective. These results suggest that the inhibition of prostanoid synthesis does not modify the electrical field-stimulated contractions of isolated horse bronchi. Since EFS-induced contractions of horse bronchi were previously shown to be of full cholinergic nature, the increase caused by diclofenac, meloxicam, carprofen, and parecoxib could be due to an inhibition of acetylcholinesterase; in accordance, these drugs potentiated exogenous acetylcholine-induced but not carbachol-induced bronchial contraction. Indomethacin and SC-560 might instead decrease bronchial contractions by inhibiting calcium currents. Clinical use of meloxicam and carprofen in horses with bronchial hyper-responsiveness requires caution for a potential risk of causing adverse effects due to bronchoconstriction.

Loss of the zona pellucida-binding protein 2 (Zpbp2) gene in mice impacts airway hypersensitivity and lung lipid metabolism in a sex-dependent fashion

The human chromosomal region 17q12-q21 is one of the best replicated genome-wide association study loci for childhood asthma. The associated SNPs span a large genomic interval that includes several protein-coding genes. Here, we tested the hypothesis that the zona pellucida-binding protein 2 (ZPBP2) gene residing in this region contributes to asthma pathogenesis using a mouse model. We tested the lung phenotypes of knock-out (KO) mice that carry a deletion of the Zpbp2 gene. The deletion attenuated airway hypersensitivity (AHR) in female, but not male, mice in the absence of allergic sensitization. Analysis of the lipid profiles of their lungs showed that female, but not male, KO mice had significantly lower levels of sphingosine-1-phosphate (S1P), very long-chain ceramides (VLCCs), and higher levels of long-chain ceramides compared to wild-type controls. Furthermore, in females, lung resistance following methacholine challenge correlated with lung S1P levels (Pearson correlation coefficient 0.57) suggesting a link between reduced AHR in KO females, Zpbp2 deletion, and S1P level regulation. In livers, spleens and blood plasma, however, VLCC, S1P, and sphingosine levels were reduced in both KO females and males. We also find that the Zpbp2 deletion was associated with gain of methylation in the adjacent DNA regions. Thus, we demonstrate that the mouse ortholog of ZPBP2 has a role in controlling AHR in female mice. Our data also suggest that Zpbp2 may act through regulation of ceramide metabolism. These findings highlight the importance of phospholipid metabolism for sexual dimorphism in AHR.

Assessing asthma in the otolaryngologist's office

PURPOSE OF REVIEW

To familiarize otolaryngologists and other practitioners with basic diagnosis and treatment of asthma in adults and children based on current literature.

RECENT FINDINGS

Increased fractional excretion of nitrous oxide and sputum eosinophils have been identified in asthmatic patients being evaluated for chronic cough and appear to be more sensitive in diagnosis than traditional spirometry. Both sublingual and subcutaneous immunotherapy modalities are effective in decreasing symptoms and medication use in patients with allergic rhinitis and allergic asthma.

SUMMARY

Undiagnosed comorbid asthma is prevalent among patients with chronic rhinosinusitis and allergic rhinitis and control of all diseases processes greatly improves quality of life. Office spirometry is a helpful tool in the evaluation and management of asthma. Otolaryngologists should be able to recognize undiagnosed or poorly controlled asthma, initiate and improve medical therapy, and treat rhinosinusitis to improve asthma control.

Potential Biomarkers for NSAID-Exacerbated Respiratory Disease

Asthma is a common chronic disease with several variant phenotypes and endotypes. NSAID-exacerbated respiratory disease (NERD) is one such endotype characterized by asthma, chronic rhinosinusitis (CRS) with nasal polyps, and hypersensitivity to aspirin/cyclooxygenase-1 inhibitors. NERD is more associated with severe asthma than other asthma phenotypes. Regarding diagnosis, aspirin challenge tests via the oral or bronchial route are a standard diagnostic method; reliable in vitro diagnostic tests are not available. Recent studies have reported various biomarkers of phenotype, diagnosis, and prognosis. In this review, we summarized the known potential biomarkers of NERD that are distinct from those of aspirin-tolerant asthma. We also provided an overview of the different NERD subgroups.

Pharmacogenomics of off-target adverse drug reactions

Off-target adverse drug reactions (ADRs) are associated with significant morbidity and costs to the healthcare system, and their occurrence is not predictable based on the known pharmacological action of the drug's therapeutic effect. Off-target ADRs may or may not be associated with immunological memory, although they can manifest with a variety of shared clinical features, including maculopapular exanthema, severe cutaneous adverse reactions (SCARs), angioedema, pruritus and bronchospasm. Discovery of specific genes associated with a particular ADR phenotype is a foundational component of clinical translation into screening programmes for their prevention. In this review, genetic associations of off-target drug-induced ADRs that have a clinical phenotype suggestive of an immunologically mediated process and their mechanisms are highlighted. A significant proportion of these reactions lack immunological memory and current data are informative for these ADRs with regard to disease pathophysiology, therapeutic targets and biomarkers which may identify patients at greatest risk. Although many serious delayed immune-mediated (IM)-ADRs show strong human leukocyte antigen associations, only a small subset have successfully been implemented in screening programmes. More recently, other factors, such as drug metabolism, have been shown to contribute to the risk of the IM-ADR. In the future, pharmacogenomic targets and an understanding of how they interact with drugs to cause ADRs will be applied to drug design and preclinical testing, and this will allow selection of optimal therapy to improve patient safety.