Does Particulate Matter Really Affect Sinusitis?

Body Mass Index and Related Risk Factor of Sinusitis Among Adults in Saudi Arabia: A Cross-Sectional Study

BACKGROUND

Chronic rhinosinusitis (CRS) is a widespread condition worldwide that is leading to a significant burden on society in terms of healthcare consumption and productivity loss. Multiple risk factors have been implicated in the pathogenesis of CRS, such as nasal allergies, bronchial asthma, smoking, nasal polyps, and immune system-related diseases. The present study aimed to assess the prevalence of CRS, the most common risk factors, and the association between diabetes, body mass index (BMI), and CRS in Saudi Arabia.

METHODS

A cross-sectional study was conducted through random sampling that included 3602 participants from different regions of Saudi Arabia from November 2022 to January 2023. Electronic questionnaires were used for data collection.

RESULTS

A total of 3602 individuals responded to our questionnaires; 948 (26.3%) were diagnosed by physicians as having chronic rhinosinusitis, and 75.1% were females. The majority (41.5%) were between the ages of 18 and 28 years. We found that smoking was significantly associated with sinusitis (OR 2.01, 95% CI 1.23-5.69) (p value 0.003) and that obesity was also significantly associated with sinusitis, 17.0% of persons with sinusitis were obese class I (BMI 30-35 kg/m²); 7.8% were obese class II (BMI>35 kg/m²); and 29.4% were overweight, whereas 45.8% were of normal weight. All percentages differ significantly from persons with normal weight (p value = 0.000). The most common risk factors for sinusitis were nasal allergies (44.4%), stuffy nose (22.8%), and deviation of the nasal septum (19.2%). All percentages differ significantly from persons without comorbidity (p value = 0.000).

CONCLUSION

The present study showed a slight increase in the prevalence of CRS in Saudi Arabia, which is attributable to increased exposure to allergens. The most common risk factors were nasal allergies, nasal blockage, deviation of the nasal septum, and asthma. There was a significant correlation between CRS and BMI in the form of increased prevalence in overweight and obese compared to normal-weight individuals.

Gene expression profiling of nasal inflammation induced by diesel particles using an in vivo system

Korean diesel particulate matter 20 (KDP20) is a pollutant comprising a complex mixture of carbon and chemical irritants. Although particulate matter and nasal inflammation are strongly associated, the underlying molecular mechanism based on systematic transcriptome analysis remains unknown. In this study, genome-wide gene expression profiles of mouse nasal tissues were determined following exposure to KDP20 for 5 and 10 days and compared with those of the control (n = 4/group). We identified 758 significant differentially expressed genes (DEGs) and classified them as 5-day-specific, 10-day-specific, and common among groups based on their expression patterns. The terms "regulation of alpha-beta T cell differentiation," "macrophage differentiation," and "cell adhesion mediated by integrin" were significantly enriched in each group. Receiver operating characteristic analysis revealed six genes as potential predictive biomarkers. The differential expression of these six genes was validated using quantitative RT-PCR (n = 3/group). Furthermore, a possible mechanism for nasal inflammation was suggested through the binding analysis between metal ions and genes. The genes identified in this study may play important roles in regulating the mechanism of nasal inflammation induced by diesel particles, especially immune cell regulation, and may function as markers for diesel particle-induced nasal inflammation.

Effect of Airborne Particulate Matter on the Immunologic Characteristics of Chronic Rhinosinusitis with Nasal Polyps

The inflammatory mechanisms of environmental pollutants in chronic rhinosinusitis (CRS) have recently been proposed. However, the mechanisms underlying the inflammatory effects of particulate matter (PM) on nasal polyp (NP) tissues remain unknown. Here we investigated the mechanism underlying the inflammatory effects of PM10 on human nasal polyp-derived fibroblasts (NPDFs). We isolated NPDFs from human NP tissues obtained from patients with CRS with NPs (CRSwNP). The NPDFs were exposed to PM10 in vitro. Immunologic characteristics were assessed using real-time polymerase chain reaction, enzyme-linked immunosorbent assay, Western blot, and flow cytometry. Additionally, we investigated the effect of NPDF-conditioned media (CM) on the expression of CD4⁺ T cell inflammatory mediators. PM10-treated NPDFs significantly upregulated interleukin (IL)-6, IL-4, and IL-33 expression and CXCL1 protein levels than PM10-treated normal tissues. MAP kinase, AP-1, and NF-kB were the primary cell signaling proteins. Immune cells in NPDF-CM had elevated IL-13, IL-17A, and IL-10 expression, but no significant difference in IFN-γ, TNF-α, and IL-4 expression. Moreover, under a Th2 inducing condition, NPDF-CM-treated CD4⁺ T cells had increased expression of IL-13, IL-10, and IL-17, which was reversed on ST2 inhibitor addition. Our study suggests that PM10 exposure could significantly increase the Th2 inflammatory pathway in NP tissues, specifically the IL-33/ST2 pathway-mediated immune response.