Establishment of a human nasal epithelium model of histamine-induced inflammation to assess the activity of fexofenadine as an inverse agonist and its link to clinical benefit.

Background: Fexofenadine (FEX) is an antihistamine that acts as an inverse agonist against histamine (HIS) receptor 1 (H1R), which mediates the allergic reaction. Inverse agonists may be more potent than neutral antagonists, as they bind the same receptor as the agonist (HIS) but stabilize the inactive form and induce an opposite pharmacological response, suppressing the basal activity of H1R and preventing HIS from binding. This study aims to establish and validate a model of HIS-induced inflammation based on fully reconstituted human nasal epithelial tissue to assess the activity of FEX as an inverse agonist in this model and explore its link to clinical benefit. Methods: The model was developed using nasal MucilAir™ (Epithelix) in vitro epithelium challenged by HIS. Two conditions were assessed in a side-by-side comparison: tissue was exposed to HIS + FEX with or without FEX pre-treatment (one-hour prior to HIS challenge). Tissue functionality, cytotoxicity, H1R gene expression, and inflammatory cytokines were assessed. Results: HIS at 100 µM induced significant 3.1-fold and 2.2-fold increases for inflammatory biomarkers interleukin (IL)-8 and IL-6, respectively (p < 0.0001), as well as rapid upregulation of H1R mRNA. Inflammatory biomarkers were inhibited by FEX and H1R expression was significantly reduced (p < 0.0001). FEX alone decreased H1R expression at all doses tested. With one-hour FEX pre-treatment, there was significantly higher downregulation of IL-8 (p < 0.05) and further downregulation of H1R expression and IL-6 versus without FEX pre-treatment; the effects of FEX were improved from 22% to 40%. Conclusion: A model of HIS-induced airway inflammation was established based on IL-8, IL-6 and H1R gene expression and was validated with FEX. FEX works as an inverse agonist, with a higher effect when used before+during versus only during the HIS challenge. Taking FEX before+during allergen exposure, or when symptoms first occur, may reduce basal activity and H1R gene expression, providing stronger protection against the worsening of symptoms upon allergen exposure.

Air pollution and rhinitis.

Rhinitis arises from either allergic or non-allergic inflammation of the nasal mucosa, characterized by the infiltration of inflammatory cells into the tissue and nasal secretions, along with structural alterations in the nasal mucosa. The pathways through which air pollution affects rhinitis may diverge from those affecting asthma. This article aims to review the effects of diverse air pollutants on the nose, the correlation of climate change and pollution, and how they aggravate the symptoms of patients with rhinitis.

Why fexofenadine is considered as a truly non-sedating antihistamine with no brain penetration: a systematic review.

OBJECTIVE: Fexofenadine is a second-generation inverse agonist of H1-receptor of histamine which is highly selective with proven efficacy in relieving symptoms associated with allergic conditions. It has an additional benefit of not penetrating the blood-brain barrier and therefore do not induce sedation and not impair the cognitive function/psychomotor performance. This review aimed at providing evidence based on available controlled studies to reinforce the non-sedative property of fexofenadine for treating patients with allergic rhinitis and urticaria. METHODS: We performed an electronic literature search using keywords such as fexofenadine, drowsiness, somnolence, sedation, fatigue, cognitive, impairment, psychomotor, driving performances, sleep, rapid eye movement, alertness, clinical study, in vitro study, in vivo study, and pharmacodynamics in the Embase search engine. The review included randomized controlled trials, review articles, systematic reviews, and meta-analyses, together with post-marketing analysis conducted in healthy subjects and patients with allergy and were focused on comparing the antihistaminic potential or safety of fexofenadine with other antihistamines or placebo. RESULTS: Positron emission tomography (PET) and proportional impairment ratio (PIR) data along with other objective tests from various studies confirmed the non-sedative property of fexofenadine. Results of brain H1-receptor occupancy (H1RO) obtained from PET showed no H1RO by fexofenadine, the receptor which is known to cause sedation of H1 antihistamines. Most studies calculating PIR value as 0 showed fexofenadine to be a non-impairing oral antihistamine regardless of dose. Clinical trials in adults and children showed fexofenadine to be well tolerated without sedative effect or impairment of cognitive/psychomotor function even at higher than recommended doses. CONCLUSION: Published literature based on various parameters and clinical trials conducted for evaluating the effect of fexofenadine on sedation and central nervous system shows fexofenadine is both clinically effective and non-sedating.

Rinite alérgica na visão do paciente / Allergic rhinitis from a patient's perspective

Os sintomas nasais têm impacto na vida dos pacientes com rinite alérgica. A maioria das pessoas alérgicas relata impacto negativo dos sintomas de alergia no trabalho e no desempenho escolar. Dentre todos os sintomas de alergia, o mais incômodo é a obstrução nasal, embora outros sintomas também tenham impacto na qualidade de vida dos pacientes, especialmente no sono. Os anti-histamínicos orais e corticosteroides nasais são as medicações mais frequentemente utilizadas para o tratamento de rinite, seguidos por descongestionantes orais ou intranasais. Os pacientes alérgicos frequentemente compram medicações sem prescrição médica nas farmácias, e nem sempre estão satisfeitos com o tratamento que lhes é oferecido. Os médicos devem trabalhar mais na comunicação com os pacientes alérgicos para atender às suas necessidades, abordando medo de efeitos colaterais, preocupações quanto aos sintomas de alergia e como estes interferem na qualidade de vida. Desse modo, a educação do paciente baseada em melhor comunicação pode facilitar o controle da rinite alérgica.

Nasal symptoms have an impact on the daily lives of patients with allergic rhinitis. Most allergic individuals report a negative impact of allergy symptoms on work and school performance. Among all allergy symptoms, the most bothersome is nasal congestion, although other symptoms also have an impact on patients' quality of life, especially on their sleep. Oral antihistamines and intranasal corticosteroids are the most frequently used medications for rhinitis, followed by oral or intranasal decongestants. Allergic patients frequently purchase different over-the-counter medications and sometimes are not satisfied with proposed treatments. Physicians should improve the communication with allergic patients to meet their needs, addressing fear of side effects, concerns about allergy symptoms and how they impact quality of life. Thus, educating patients through better communication may improve the control of allergic rhinitis.