Phosphodiesterase 4 Inhibitors in Allergic Rhinitis/Rhinosinusitis

Functional rescue of CFTR in rectal organoids from patients carrying R334W variant by CFTR modulators and PDE4 inhibitor Roflumilast

BACKGROUND

Many disease-causing variants in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene remain uncharacterized and untreated. Restoring the function of the impaired CFTR protein is the goal of personalized medicine, particularly in patients carrying rare CFTR variants. In this study, functional defects related to the rare R334W variant were evaluated after treatment with CFTR modulators or Roflumilast, a phosphodiesterase-4 inhibitor (PDE4i).

METHODS

Rectal organoids from subjects with R334W/2184insA and R334W/2183AA > G genotypes were used to perform the Forskolin-induced swelling (FIS) assay. Organoids were left drug-untreated or treated with modulators VX-770 (I), VX-445 (E), and VX-661 (T) mixed, and their combination (ETI). Roflumilast (R) was used alone or as a combination of I + R.

RESULTS

Our data show a significant increase in FIS rate following treatment with I alone. The combined use of modulators, such as ETI, did not increase further swelling than I alone, nor in protein maturation. Treatment with R shows an increase in FIS response similar to those of I, and the combination R + I significantly increases the rescue of CFTR activity.

CONCLUSIONS

Equivalent I and ETI treatment efficacy was observed for both genotypes. Furthermore, significant organoid swelling was observed with combined I + R used that supports the recently published data describing a potentiating effect of only I in patients carrying the variant R334W and, at the same time, corroborating the role of strategies that include PDE4 inhibitors further to potentiate the effect of I for this variant.

Pathogenesis of allergic diseases and implications for therapeutic interventions

Allergic diseases such as allergic rhinitis (AR), allergic asthma (AAS), atopic dermatitis (AD), food allergy (FA), and eczema are systemic diseases caused by an impaired immune system. Accompanied by high recurrence rates, the steadily rising incidence rates of these diseases are attracting increasing attention. The pathogenesis of allergic diseases is complex and involves many factors, including maternal-fetal environment, living environment, genetics, epigenetics, and the body's immune status. The pathogenesis of allergic diseases exhibits a marked heterogeneity, with phenotype and endotype defining visible features and associated molecular mechanisms, respectively. With the rapid development of immunology, molecular biology, and biotechnology, many new biological drugs have been designed for the treatment of allergic diseases, including anti-immunoglobulin E (IgE), anti-interleukin (IL)-5, and anti-thymic stromal lymphopoietin (TSLP)/IL-4, to control symptoms. For doctors and scientists, it is becoming more and more important to understand the influencing factors, pathogenesis, and treatment progress of allergic diseases. This review aimed to assess the epidemiology, pathogenesis, and therapeutic interventions of allergic diseases, including AR, AAS, AD, and FA. We hope to help doctors and scientists understand allergic diseases systematically.

Advances in the development of phosphodiesterase-4 inhibitors

Phosphodiesterase 4 (PDE4) hydrolyzes cyclic adenosine monophosphate (cAMP) and plays a vital roles in many biological processes. PDE4 inhibitors have been widely studied as therapeutics for the treatment of various diseases, including asthma, chronic obstructive pulmonary disease (COPD) and psoriasis. Many PDE4 inhibitors have progressed to clinical trials and some have been approved as therapeutic drugs. Although many PDE4 inhibitors have been approved to enter clinical trials, however, the development of PDE4 inhibitors for the treatment of COPD or psoriasis has been hampered by their side effects of emesis. Herein, this review summarizes advances in the development of PDE4 inhibitors over the last ten years, focusing on PDE4 sub-family selectivity, dual target drugs, and therapeutic potential. Hopefully, this review will contribute to the development of novel PDE4 inhibitors as potential drugs.

Effect of immunostimulation with bacterial lysate on the clinical course of allergic rhinitis and the level of γδT, iNKT and cytotoxic T cells in children sensitized to grass pollen allergens: A randomized controlled trial

Background

There are many drugs for allergic rhinitis (AR), however, these drugs show variable clinical effectiveness and some side effects. Therefore, new methods of AR pharmacotherapy are being sought.

Objectives

The objectives of this study were to evaluate the efficacy of polyvalent mechanical bacterial lysate (PMBL) therapy in improving the clinical course of grass pollen-induced AR (seasonal AR, SAR) in children and its effect on changes in the blood level of the γδT, iNKT and cytotoxic T cell subsets.

Methods

Fifty children with SAR were enrolled in this study and were randomly assigned to either the PMBL group or the placebo group. The severity of SAR symptoms was assessed using the total nasal symptom score (TNSS) and visual analogue scale (VAS). During two visits (V1, V2), peak nasal inspiratory flow (PNIF) was measured and peripheral blood was collected for immunological analyses. The study also included 2 telephone contacts (TC1, TC2).

Results

The severity of the nasal symptoms of SAR on the TNSS scale was revealed to have a significantly lower impact in the PMBL group vs the placebo group at measuring points TC1 and V2 (p = 0.01, p = 0.009, respectively). A statistically significantly lower mean severity of nasal symptoms of SAR on the VAS scale was recorded for children in the PMBL group compared to the placebo group at measuring points TC1, V2 and TC2 (p = 0.04, p = 0.04, p = 0.03, respectively). The compared groups do not show significant differences in terms of PNIF values at individual measuring points. There were no statistically significant changes in immune variables. For both groups, there was a statistically significant association between the level of Th1-like γδT cells and the severity of SAR symptoms expressed on the TNSS scale (p = 0.03) - the lower the level of Th1-like γδT cells, the higher the TNSS value.

Conclusion

Administration of sublingual PMBL tablets during the grass pollen season proves to have a high efficacy in alleviating SAR symptoms in children sensitized to grass pollen allergens. Th1-like γδT cells may be used as potential markers for SAR severity in children.

Clinical trial registration

ClinicalTrials.gov, identifier (NCT04802616).

Clinical efficacy and safety of topical difamilast in the treatment of patients with atopic dermatitis: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To investigate the clinical efficacy and safety of topical difamilast in mild-to-moderate atopic dermatitis (AD).

METHODS

Only randomized controlled trials (RCTs) that compared topical difamilast with vehicle treatment for patients with AD were included. PubMed, Web of Science, Ovid Medline, Cochrane Library, ClinicalTrials.gov and JapicCTI were searched to 10 April 2022.

RESULTS

Five studies enrolling a total of 1009 patients with mild-to-moderate AD were identified. Compared with the topical vehicle, topical difamilast was associated with a significantly higher success rate according to the Investigator's Global Assessment score at week 4 (relative risk, 2.82; 95% confidence interval [CI]: 2.11-3.77). Compared with the vehicle, difamilast was associated with a significant decrease in day 28 eczema area and severity index scores (mean difference [MD], -4.10; 95% CI: -5.32 to -2.87), verbal rating scale scores (MD, -0.51; 95% CI: -0.71 to -0.32), visual analog scale scores (MD, -12.15; 95% CI: -19.70 to -4.61), patient-oriented eczema measure values (MD, -3.99; 95% CI: -4.91 to -3.07), and total affected body surface area (MD, -6.48; 95% CI: -8.09 to -4.87). No difference in treatment-related adverse events was identified.

CONCLUSIONS

This meta-analysis suggests that topical difamilast is an effective and safe treatment for mild-to-moderate AD.

Can Phosphodiesterase 4 Inhibitor Therapy Be Used in Respiratory Diseases Other Than Chronic Obstructive Pulmonary Disease?

Selective phosphodiesterase 4 (PDE4) inhibitors have been extensively studied for the treatment of various respiratory diseases due to their broad anti-inflammatory and/or bronchodilator effects. Roflumilast, an oral selective PDE4 inhibitor, is currently used as a second-line treatment in patients with chronic obstructive pulmonary disease (COPD) with chronic bronchitis. Despite its proven efficacy in other respiratory disorders, including asthma, no other PDE4 inhibitor is approved for respiratory pathologies. This systematic review summarizes the therapeutic action of PDE4 inhibitors, their limitations, recent therapeutic success, and future targets for their use in respiratory diseases other than COPD. An electronic literature search was conducted on four databases, namely, PubMed, PubMed Central, Google Scholar, and ScienceDirect, to collect data on related studies done in humans and published in the English language in the last five years. After extensive analysis and quality appraisal, 11 studies were eligible and thus included in this review, consisting of two randomized controlled trials (RCT), one systematic review and meta-analysis, and eight literature reviews. Roflumilast is not approved for the treatment of asthma due to associated adverse effects and comparable efficacy to inhaled corticosteroids, which are considered the mainstay of asthma maintenance therapy. Hence, the importance of balancing the efficacy with minimizing the side effects is highlighted. Tanimilast (CHF6001), an inhalational selective PDE4 inhibitor, and ensifentrine, a combined PDE3/4 inhibitor, demonstrate the recent therapeutic success in asthma and warrant further large-scale clinical studies. Future researchers will focus on the specific endotype than the phenotype in asthma as a meaningful therapeutic approach due to the high heterogeneity noted in asthma. Current evidence suggests the possibility of PDE4 inhibitors as a novel therapeutic option for chronic cough, allergic rhinitis, and cystic fibrosis. Further evidence from new studies is eagerly anticipated to better understand the efficacy and safety of PDE4 inhibitors in these respiratory diseases.

The traditional and modern uses of Selaginella tamariscina (P.Beauv.) Spring, in medicine and cosmetic: Applications and bioactive ingredients

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of the plant Selaginella tamariscina (P.Beauv.) Spring (spike moss) are used for a long time in Asia, for the treatment of multiple diseases and conditions. Aqueous and alcoholic leave extracts are used by local communities. In China, the plant (Juan bai) is listed on the Pharmacopoeia. In South Korea, the use of this plant (Kwon Baek) is mentioned in the book Dongui-Bogam (Heo Jun 1613), at the origin of the Hyungsang medicine. S. tamariscina is traditionally used in Vietnam (mong lung rong), Thailand (dok hin), Philippines (pakong-tulog) and other Asian countries.

AIM OF THE STUDY

To provide an analysis of the multiple traditional and current uses of S. tamariscina extracts (STE) in the field of medicine and cosmetic. The review is also intended at identifying the main natural products at the origin of the many pharmacological properties reported with these extracts (anti-inflammatory, antioxidant, antidiabetic, antibacterial, antiallergic, anticancer effects).

METHODS

Extensive database retrieval, such as SciFinder and PubMed, was performed by using keywords like " Selaginella tamariscina", "spike moss", "Selaginellaceae ". Relevant textbooks, patents, reviews, and digital documents were consulted to collate all available scientific literature and to provide a complete science-based survey of the topic.

RESULTS

Different solvents and methods are used to prepare STE. The process can largely modify the natural product content and properties of the extracts. STE display a range of pharmacological effects, useful to treat metabolic disorders, several inflammatory diseases and various cancers. A specific carbonized extract (S. tamariscina carbonisatus) has shown hemostatic effects, whereas standard STE can promote blood circulation. Many patented STE-containing cosmetic preparations are reviewed here. Several biflavonoids (chiefly amentoflavone) and phenolic compounds (selaginellin derivatives) are primarily responsible for the observed pharmacological properties. Potent inhibitors of protein tyrosine phosphatase 1 B (PTP1B), phosphodiesterase-4 (PDE4), and repressor of pro-inflammatory cytokines expression have been identified from STE.

CONCLUSION

The traditional use of STE supports the research performed with this plant. There are robust experimental data, based on in vitro and in vivo models, documenting the use of STE to treat type 2 diabetes, several inflammatory diseases, and some cancers (in combination with standard chemotherapy). Selaginella tamariscina (P.Beauv.) is a prime reservoir for amentoflavone, and many other bioactive natural products. The interest of the plant in medicine and cosmetic is amply justified.

Phosphodiesterase-4 Inhibitors for Non-COPD Respiratory Diseases

Selective phosphodiesterase (PDE) inhibitors are a class of nonsteroid anti-inflammatory drugs for treating chronic inflammatory diseases. Modulation of systemic and airway inflammation is their pivotal mechanism of action. Furthermore, PDE inhibitors modulate cough reflex and inhibit airway mucus secretion. Roflumilast, a selective PDE4 inhibitor, has been extensively studied for the efficacy and safety in chronic obstructive pulmonary disease (COPD) patients. According to the mechanisms of action, the potential roles of PDE inhibitors in treating chronic respiratory diseases including severe asthma, asthma-COPD overlap (ACO), noncystic fibrosis bronchiectasis, and chronic cough are discussed. Since roflumilast inhibits airway eosinophilia and neutrophilia in COPD patients, it reduces COPD exacerbations in the presence of chronic bronchitis in addition to baseline therapies. The clinical studies in asthma patients have shown the comparable efficacy of roflumilast to inhaled corticosteroids for improving lung function. However, the clinical trials of roflumilast in severe asthma have been limited. Although ACO is common and is also associated with poor outcomes, there is no clinical trial regarding its efficacy in patients with ACO despite a promising role in reducing COPD exacerbation. Since mucus hypersecretion is a result of neutrophil secretagogue in patients with chronic bronchitis, experimental studies have shown that PDE4s are regulators of the cystic fibrosis transmembrane conductance regulator (CFTR) in human airway epithelial cells. Besides, goblet cell hyperplasia is associated with an increased expression of PDE. Bronchiectasis and chronic bronchitis are considered neutrophilic airway diseases presenting with mucus hypersecretion. They commonly coexist and thus lead to severe disease. The role of roflumilast in noncystic fibrosis bronchiectasis is under investigation in clinical trials. Lastly, PDE inhibitors have been shown modulating cough from bronchodilation, suppressing transient receptors potential (TRP), and anti-inflammatory properties. Hence, there is the potential role of the drug in the management of unexplained cough. However, clinical trials for examining its antitussive efficacy are pivotal. In conclusion, selective PDE4 inhibitors may be potential treatment options for chronic respiratory diseases apart from COPD due to their promising mechanisms of action.

Yiqi Jiemin decoction alleviates allergic rhinitis in a guinea pig model by suppressing inflammation, restoring Th1/Th2 balance, and improving cellular metabolism

We investigated the mechanisms underlying the therapeutic effects of Yiqi Jiemin decoction (YJD), a traditional Chinese medicine (TCM), in the ovalbumin (OVA)-induced allergic rhinitis (AR) model in guinea pigs. YJD significantly decreased infiltration of mast cells and eosinophils into the nasal mucosa of AR model guinea pigs. YJD also increased expression of TGF-β in the nasal mucosa, restored the balance of Th1/Th2 immune cell responses, and decreased serum levels of various pro-inflammatory mediators, including histamine (HA), neuropeptide Y (NPY), acetylcholine (ACH), norepinephrine and immunoglobulin E (IgE). Metabolic analyses using liquid chromatography coupled with high-resolution mass spectrometry revealed that YJD improved cellular metabolism in AR model guinea pigs and increased serum levels of glycocholic acid while decreasing levels 1-palmitoyl lysophosphatidic acid. RNA-sequencing analysis identified BPIFB2 as a potential diagnostic biomarker and therapeutic target for AR. Functional enrichment analyses showed that YJD significantly inhibited cytokine secretion pathways in AR model guinea pigs. These findings demonstrate that YJD protects against OVA-induced AR in guinea pigs by suppressing inflammation in the nasal mucosa, restoring Th1/Th2 balance, and improving cellular metabolism.