Oxygen matters: hypoxia as a pathogenic mechanism in rhinosinusitis

A Supplement with Ribes Nigrum, Boswellia Serrata, Bromelain and Vitamin D to Stop Local Inflammation in Chronic Sinusitis: A Case-Control Study

Although chronic sinusitis widely affects the adult population, the treatments currently used did not always satisfactorily solve the symptoms. Traditional therapy with steroids and antibiotics presents risks and benefits and the new drugs, i.e., monoclonal antibody, are valid solutions despite being quite expensive. Natural molecules could be a valid treatment that combines good efficacy and low price. We conducted a case -control study to evaluate the benefit of an oral supplement with Ribes nigrum, Boswellia serrata, Bromelain and Vitamin D on chronic sinusitis symptoms. 60 patients were randomly assigned to one of the three groups: control using nasal steroids only, treatment 1 using nasal steroid and 1 dose of the oral supplement for 30 days and treatment 2 in which patients used nasal steroid and two oral supplement doses daily for 15 days. Conditions of the nasal mucosa and a blood sample (WBC, IgE and CRP) were analyzed at T0, T1 (15 days after treatment) and T2 (30 days after treatment. Patients treated with the supplement improved their nasal findings (hyperemia of mucosa and rhinorrhea) with statistically significant differences from the control. Our preliminary data suggest that the addition of supplement containing Ribes nigrum, Boswellia serrata, Vitamin D and Bromelain to the traditional local therapy (nasal spray with cortisone) can be a supporting therapy to modulate the local inflammation in the nose in patients affected by chronic sinusitis.

The role of hypoxia in the pathophysiology of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the nasal cavity characterized by excessive nasal mucus secretion and nasal congestion. The development of CRS is related to pathological mechanisms induced by hypoxia. Under hypoxic conditions, the stable expression of both Hypoxia inducible factor-1 (HIF-1) α and HIF-2α are involved in the immune response and inflammatory pathways of CRS. The imbalance in the composition of nasal microbiota may affect the hypoxic state of CRS and perpetuate existing inflammation. Hypoxia affects the differentiation of nasal epithelial cells such as ciliated cells and goblet cells, induces fibroblast proliferation, and leads to epithelial-mesenchymal transition (EMT) and tissue remodeling. Hypoxia also affects the proliferation and differentiation of macrophages, eosinophils, basophils, and mast cells in sinonasal mucosa, and thus influences the inflammatory state of CRS by regulating T cells and B cells. Given the multifactorial nature in which HIF is linked to CRS, this study aims to elucidate the effect of hypoxia on the pathogenic mechanisms of CRS.

Transcriptome sequencing reveals altered ciliogenesis under hypoxia in nasal epithelial cells from chronic rhinosinusitis with nasal polyps

Background

Hypoxia is considered a key factor in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). However, the specific mechanism driving polypogenesis under hypoxic conditions is unclear. This study aimed to explore hypoxia-induced alterations in the transcriptome of human nasal epithelial cells (HNECs) in vitro.

Methods

HNECs derived from the tissue of patients with CRSwNP were established as air-liquid interface (ALI) cultures. Confluent cultures were kept submerged or treated with cobalt chloride (CoCl2) to induce hypoxia. Transcriptome analysis was used to identify key mRNAs involved in this process. Real-time PCR (RT-PCR), Western blotting, and immunofluorescence were used to observe the effects of hypoxia on ciliogenesis.

Results

Numerous genes, biological processes and pathways were altered under submerged culture conditions or after CoCl2 treatment. Analysis of the results under both hypoxic conditions revealed that the transcriptional program responsible for ciliogenesis was significantly impaired. Downregulation of cilia-related genes and inhibition of ciliated cell differentiation under hypoxia were confirmed by RT-PCR, Western blot and immunofluorescence analyses.

Conclusion

Hypoxia impairs ciliogenesis and ciliary function in HNECs, which might play a role in the pathogenesis of CRSwNP.

In vitro evaluation of a novel oxygen-generating biomaterial for chronic rhinosinusitis therapy

BACKGROUND

Hypoxia due to closure at the ostiomeatal complex is widely considered one of the major pathogenic mechanisms leading to chronic inflammation in chronic rhinosinusitis (CRS). The objective of this study was to develop and characterize an oxygen-generating biomaterial (OGB) as an innovative treatment strategy for CRS.

METHODS

An OGB was fabricated by coating hydrophobic beeswax (BW, 15mg or 30mg) on the surface of calcium peroxide - catalase complex (CPO-CA, 30mg) and characterized using scanning electron microscopy (SEM). In vitro releases of both oxygen and hydrogen peroxide (H₂ O₂ ) were spectrophotometrically quantified, and cytotoxicity in human sinonasal epithelial cells (HSNECs) was evaluated. The influence of OGB on transepithelial Cl^- secretion was also determined by pharmacologically manipulating HSNECs, cultured under hypoxic conditions, in Ussing chambers.

RESULTS

Three groups of OGBs: (1) CPO only; (2) CPO coated with CA and BW (1:1 ratio, CPO-CA(1)-BW(1)); and (3) CPO coated with CA and BW (1:0.5 ratio, CPO-CA(1)-BW(0.5) were analyzed for accumulated oxygen release over 7 days: highest release (mmol/mg) was observed in CPO-CA(1)-BW(1) = 0.11 ± 0.003, followed by CPO-CA(1)-BW(0.5) = 0.08 ± 0.010, and CPO = 0.05 ± 0.004 (p < 0.0001). H₂ O₂ production (mM) was significantly higher in CPO (1.87 ± 0.50) compared to CPO-CA (1)-BW(1) (0.00 ± 0.00) (p < 0.001) after 24 h. CPO-CA(1)-BW(1) showed significantly reduced cytotoxicity and increased Cl^- transport compared to the CPO group.

CONCLUSION

A novel OGB (CPO-CA-BW complex) exhibited sustained oxygen release over 7 days without significant cytotoxicity after 24 h in vitro. Preclinical studies evaluating the efficacy of OGB in CRS are warranted, especially for potential therapy in an obstruction-based CRS model.

The airway epithelium during infancy and childhood: A complex multicellular immune barrier. Basic review for clinicians

The airway epithelium is a complex multicellular layer that extends from the nasopharynx to the small airways. It functions as an immune respiratory barrier during early life that develops, matures, and regenerates to adapt to the changes in the environment. While airway epithelial abnormalities have been identified in several clinical disorders, there is increasing interest in understanding its basic regulation and structure in humans. Indeed, recent advances in technology (e.g. single-cell analysis and new human airway epithelial cell models) have allowed us to identify additional cellular subtypes and functions that overall have greatly improved our understanding of the airway epithelium during health and disease. In this review we summarize key features of the airway epithelium including: 1) multilayer structure and cell heterogeneity; 2) adaptability to different environmental and developmental stimuli; 3) innate recognition; and 4) orchestration of immune responses. We discuss these features with a translational and clinical prospective focusing on the development of human respiratory immunity, particularly during early life.

Study on the effects of desloratadine citrate disodium on the postoperative complications and inflammatory response in patients with chronic sinusitis undergoing endoscopic sinus surgery

OBJECTIVE

To explore the effects of desloratadine citrate disodium on the postoperative complications and inflammatory markers in patients with chronic sinusitis undergoing endoscopic sinus surgery.

METHODS

From June 2019 to December 2020, the patients with chronic sinusitis who received treatment in our hospital were selected and divided into the control group (CG) and experimental group (EG). In both groups, patients were given endoscopic sinus surgery. On this basis, patients were treated with desloratadine citrate disodium in the EG. The total effective rate of the operation and the incidence of complications were compared between the two groups, and the VAS scores of clinical symptoms were compared between the two groups after treatment. Meanwhile, the changes of serum TIgE, ECP and inflammatory factors were compared between the two groups, and the nasal mucociliary clearing function was compared between the two groups before and after treatment.

RESULTS

After treatment, the total effective rate was 94.9% in the EG, which was significantly higher than that in the CG (82.2%). The levels of serum interleukin-6 (IL-6), interleukin-8 (IL-8), high-sensitivity C-reactive protein (hs-CRP) and tumor necrosis factor-α (TNF-α) in the EG were significantly lower than those in the CG, and the levels of serum TIgE and ECP were also significantly lower than those in the CG. After treatment for 3 months, the mucociliary clearance rate and mucociliary clearance rate in the EG were significantly higher than those in the CG, while the saccharin clearance time was significantly shorter than that in the CG. The incidence of complications in the EG was significantly lower than that in the CG (all P < 0.05).

CONCLUSION

Desloratadine citrate disodium combined with endoscopic sinus surgery can improve the clinical efficacy, reduce the level of inflammatory factors and effectively reduce the incidence of complications in patients with chronic sinusitis.

Interleukin 13 (IL-13) alters hypoxia-associated genes and upregulates CD73

BACKGROUND

Interleukin 13 (IL-13) is a pleiotropic cytokine that has been shown to be important in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) and other type 2 inflammation-related diseases. Increased IL-13 expression can elicit several pro-inflammatory effects, including eosinophilia, and pathology such as increased mucus secretion. Polypogenesis in chronic rhinosinusitis (CRS) can be caused by hypoxia, which can also lead to hyperpermeability of airway epithelium and epithelium-to-mesenchymal translation through the upregulation of hypoxia-associated genes, such as HIF1. Whether T-helper 2 (Th2) inflammatory cytokines, such as IL-13, can also induce sinonasal epithelial hypoxia-associated genes is currently unknown.

METHODS

Human air-liquid interface (ALI) sinonasal epithelial cell cultures treated with recombinant IL-13 were analyzed by real-time polymerase chain reaction (PCR) and flow cytometry to determine the effect on epithelial cells.

RESULTS

Whole tissue from CRSwNP subjects showed increased HIF1A gene expression. Treatment of fully differentiated human ALI cultures with IL-13 resulted in a concurrent increase in HIF1A and ARNT messenger RNA (mRNA) expression. However, the level of EPAS1 expression was significantly reduced. IL-13 also had a dose-dependent response on the expression of HIF genes and the time course experiment showed peak expression of HIF1A and ARNT at 5 to 7 days poststimulation. Remarkably, CD73 surface expression also peaked at day 5 poststimulation.

CONCLUSION

Our data suggests that IL-13 can induce hypoxia signaling pathway genes leading to surface expression of CD73, which has an anti-inflammatory effect.

The Development of Glaucoma after Surgery-Indicated Chronic Rhinosinusitis: A Population-Based Cohort Study

This study investigates the development of glaucoma in subjects with surgery-indicated chronic rhinosinusitis (CRS) by the use of the National Health Insurance Research Database in Taiwan. Individuals that received the functional endoscopic sinus surgery (FESS) with a diagnostic code of CRS were regarded as surgery-indicated CRS and enrolled in the study group. Four non-CRS patients were age- and gender-matched to each patient in the study group. The exclusion criteria included legal blindness, ocular tumor, history of eyeball removal, and previous glaucoma. The outcome was regarded as the development of glaucoma, and conditional logistic regression was used for the statistical analysis, which involved multiple potential risk factors in the multivariate model. A total of 6506 patients with surgery-indicated CRS that received FESS and another 26,024 non-CRS individuals were enrolled after exclusion. The age and gender distributions were identical between the two groups due to matching. There were 108 and 294 glaucoma events in the study group and control group, respectively, during the follow-up period, and the study group had a significantly higher adjusted hazard ratio (1.291, 95% confidential interval: 1.031–1.615). The cumulative probability analysis also revealed a correlation between the occurrence of glaucoma and the CRS disease interval. In the subgroup analysis, the chance of developing open-angle glaucoma and normal-tension glaucoma was significantly higher in the study group than in the control group. In conclusion, the existence of surgery-indicated CRS is a significant risk factor for the development of glaucoma, which correlated with the disease interval.

Epithelial physical barrier defects in chronic rhinosinusitis

INTRODUCTION

Chronic rhinosinusitis (CRS) is a common upper airway disease with a prevalence of greater than 10% of the general population. Although the pathogenesis of CRS remains poorly understood, there is growing evidence indicating that epithelial physical barrier defects play an important role in CRS pathogenesis. Areas covered: Epithelial physical barriers are maintained by various intercellular junctions, especially tight junctions (TJs). Recent studies suggest that the expression of TJ molecules and epithelial barrier function in human nasal epithelium are modulated by various internal and external factors. This review summarizes recent advances regarding the structure, function, and regulating mechanisms of the epithelial physical barrier in the context of CRS. Expert opinion: Available data indicate that epithelial physical barrier defects in CRS can result from inhaled allergens, microbial or virus infections, cytokines, hypoxia, or zinc deficiency, among other causes. Several genes/molecules, such as SPINK5, S100A7, S100A8/9, PCDH1, NDRG1, SPRR, and p63 are involved in modulating the physical barrier function in the context of CRS. The exact mechanisms and molecular pathways that lead to these barrier defects, however, require additional study. Additional work is necessary to further explore the epithelial physical barrier function in normal and pathologic sinonasal mucosa.

Inflammation and Endotyping in Chronic Rhinosinusitis-A Paradigm Shift

Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory condition of the paranasal sinuses and nasal passage. It is characterized as inflammation of the sinonasal passage, presenting with two or more symptoms (nasal blockage, secretions, facial pain and headaches) for more than 12 weeks consecutively. The disease is phenotypically differentiated based on the presence of nasal polyps; CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Traditionally, CRSwNP has been associated with a type 2 inflammatory profile, while CRSsNP has been associated with a type 1 inflammatory profile. Extensive work in characterizing the inflammatory profiles of CRS patients has challenged this dichotomy, with great variation both between and within populations described. Recent efforts of endotyping CRS based on underlying pathophysiology have further highlighted the heterogeneity of the disease, revealing mixed inflammatory profiles coordinated by a number of inflammatory cell types. This review will highlight the current understanding of inflammation in CRS, and discuss the importance and impact of refining this understanding in the development of appropriate treatment options for CRS sufferers.