Role of C3a as a Novel Regulator of 25(OH)D3 to 1α,25-Dihydroxyvitamin D3 Metabolism in Upper Airway Epithelial Cells

Complement's involvement in allergic Th2 immunity: a cross-barrier perspective

Type 2 (Th2) allergic diseases are chronic conditions characterized by a Th2-polarized immune response to allergens. These diseases can be categorized by affected barrier sites: skin (atopic dermatitis, allergic contact dermatitis), gut (food allergy), and respiratory tract (e.g., asthma, chronic rhinosinusitis). The global prevalence of Th2 allergic diseases has increased the need for a deeper understanding of their pathophysiology. Several associations have been identified between genetic variants in the genes encoding components of the complement system and allergic disease. Moreover, levels of several complement proteins are elevated in patients with allergy. Experimental evidence demonstrates that the complement system plays a critical role in the development of these diseases across barrier sites. While site-specific differences exist in the complement components involved, key pathways, particularly C3 and C5, are prominent across the skin, gut, and lung.

Serum 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D are decreased in dogs with sinonasal aspergillosis

Canine sinonasal aspergillosis (SNA) is a poorly understood disease and remains a challenge to treat. Hypovitaminosis D is associated with many infectious diseases in humans and Vitamin D (VitD) deficiency in experimental mice decreases resistance to Aspergillus fumigatus. The objective of this study was to determine whether dogs with SNA have different VitD metabolite concentrations compared to healthy dogs (HD) and dogs with other nasal conditions and if those concentrations change after cure for SNA dogs. Twenty-two dogs with SNA, 12 HD, 9 dogs with lymphoplasmacytic rhinitis (LPR) and 10 dogs with nasal neoplasia (NN) were included. Serum 25-hydroxyvitamin D2 (25(OH)D2), 25-hydroxyvitamin D3 (25(OH)D3), 24,25-dihydroxyvitamin D3 (24,25(OH)2D3), 3-epimer-25-hydroxyvitamin D3 (3-epi-25(OH)D3) concentrations were measured by a certified liquid chromatography tandem mass spectrometry method at time of diagnosis or revisit. Twelve SNA dogs were available for serial blood collection until cure. Serum 25(OH)D and 24,25(OH)2D3 were lower in dogs with SNA (mean ± standard deviation; 23 ng/ml ± 7.3 and 10.2 ng/ml ± 4.2, respectively) than in HD (34.1 ng/ml ± 7.5; P = 0.007 and 18.2 ng/ml ± 5.4; P = 0.002) while there was no difference among the other groups. Cured SNA dogs had higher serum 25(OH)D concentrations (27.7 ng/ml ± 9.4) compared to before treatment (23.1 ng/ml ± 7.7; P = 0.0002). These results further support the rationale that VitD may play a role in the complex SNA pathophysiology. Whether lower VitD status contributes to the development of the disease or is a consequence of it is unknown.

Intranasal Calcitriol Accelerates Improvement of Sinonasal Inflammation and Olfactory Impairment in Mice After Cessation of Chronic Cigarette-Smoke Exposure

RATIONALE

Smoking has been shown to be associated with circulating deficiencies in 25(OH)D3 and reduced sinonasal tissue levels of the active form of vitamin D, 1,25(OH)2D3. Given vitamin D's ability to reduce inflammation, we sought to examine if intranasal (IN) delivery of calcitriol [clinical analog of 1,25(OH)2D3] could reduce inflammation and improve disease severity in a murine model of chronic cigarette smoke-induced sinonasal inflammation (CS-SI).

METHODS

Mice were exposed to CS 5 h/day, 5 days/week for 9 months, and then began IN calcitriol three times per week for 4 weeks. Micro-CT was used to assess disease severity. Sinonasal tissues were collected for RNA-seq analysis. Olfactory function was assessed using a T-maze odorant avoidance sniff behavior test. Nasal lavage fluid (NALF) was used for cytology and cytokines analysis.

RESULTS

Quantification of disease severity by micro-CT showed IN calcitriol reduced opacification by 18%, as compared to smoke cessation alone, in which only a 5% reduction was noted. H&E analysis of NAFL demonstrated heightened neutrophil infiltration and neutrophil-associated chemokines in CS-SI mice, which was reduced with IN calcitriol treatment. RNA-seq pathway analysis demonstrated that smoking was associated with odorant binding changes and that calcitriol treatment reduced neutrophil migration and inflammation. Lastly, IN calcitriol reversed olfactory loss caused in CS-SI.

CONCLUSIONS

IN delivery of calcitriol accelerates inflammatory resolution in the nose and olfactory mucosa after prolonged CS exposure. Furthermore, treatment was associated with improved olfactory function in mice CS-SI, as such local delivery of calcitriol may serve as a novel treatment for modulating sinonasal inflammation.

Potential role of Vitamin D in immune response in patients with viral hepatitis

BACKGROUND

To study the relationship of Vitamin D with innate and adaptive immune response parameters in chronic hepatitis B and C patients.

METHODS

The laboratory data between January 1, 2013 and February 1, 2023, for patients with chronic hepatitis B (CHB), and chronic hepatitis C (CHC) were extracted. Serum 25-hydroxyl vitamin D, hepatitis B virus serological markers, complements, and subsets of T lymphocytes were determined. Study cohorts were divided into groups based on serum 25-hydroxyl vitamin D levels with further evaluation of laboratory data.

RESULTS

In CHB and CHC patients the percentage of CD4+ T lymphocytes and the CD4+/CD8+ ratio significantly decreased (P < 0.05), but the percentage of CD8+ increased (P < 0.05) compared to the control group. In CHB patients Vitamin D decrease was significant (P < 0.001) but not in CHC patients. Vitamin D showed a moderate negative influence on the CD8 cell count in CHB patients. The positive ratio of HBV DNA and HBsAg decreased with increasing serum vitamin D levels. The vitamin D deficient group showed significantly lower antibody production compared to the normal group, and exhibited significantly decreased CD4 numbers and increased CD8 numbers (P < 0.05 and P < 0.001, respectively), while the CD4/CD8 ratio was also significantly decreased in the insufficiency group (P < 0.001). Complement C3 levels were not associated with CD4 and CD8, but had an inverse relation with Vitamin D. Vitamin D levels were significantly associated with complement C3, CD8+, CD4+, CD19+ cells, and HBV DNA levels.

CONCLUSIONS

Vitamin D may be a modulator of immune function not only via CD8+ and CD4+ cells but also via CD19+ cells in the course of chronic HBV infection. The negative relationship between vitamin D and complement C3 needs elucidation. Moreover, the increased proportion of B cells and decreased CD4+ cells in Vitamin D deficiency disrupt the immune response against HBV since the expected antibody response was not obtained despite the increase in B cell ratio. This indicates an influence of CD4+ cells for B cell functionality. In summary, sufficient levels of Vitamin D may lead to a sustained virological response that is debatable by artificially correcting the deficiency.

Local complement activation and modulation in mucosal immunity

The complement system is an evolutionarily conserved arm of innate immunity, which forms one of the first lines of host response to pathogens and assists in the clearance of debris. A deficiency in key activators/amplifiers of the cascade results in recurrent infection, whereas a deficiency in regulating the cascade predisposes to accelerated organ failure, as observed in colitis and transplant rejection. Given that there are over 60 proteins in this system, it has become an attractive target for immunotherapeutics, many of which are United States Food and Drug Administration-approved or in multiple phase 2/3 clinical trials. Moreover, there have been key advances in the last few years in the understanding of how the complement system operates locally in tissues, independent of its activities in circulation. In this review, we will put into perspective the abovementioned discoveries to optimally modulate the spatiotemporal nature of complement activation and regulation at mucosal surfaces.

Pathogenesis and treatment of chronic rhinosinusitis from the perspective of sinonasal epithelial dysfunction

Background

Chronic rhinosinusitis (CRS) is a clinical syndrome primarily characterized by long-term mucosal inflammation of the nasal cavity and sinuses. The pathogenesis of CRS is still unclear due to its high heterogeneity. A number of studies have recently focused on the sinonasal epithelium. Thus, there has been a quantum leap in awareness of the role of the sinonasal epithelium, which is now understood as an active functional organ rather than simply an inert mechanical barrier. Undoubtedly, epithelial dysfunction plays a vital role in the onset and development of CRS.

Objective

In this article, we discuss the potential contribution of sinonasal epithelium dysfunction to CRS pathogenesis and explore a few current and developing therapeutic options targeting the sinonasal epithelium.

Results

Impaired mucociliary clearance (MCC) and an abnormal sinonasal epithelial barrier are usually considered to be the main causative factors in CRS. Epithelial-derived bioactive substances, such as cytokines, exosomes, and complements, play a vital role in the regulation of innate and adaptive immunity and contribute to the pathophysiological alterations of CRS. The phenomena of epithelial-mesenchymal transition (EMT), mucosal remodeling, and autophagy observed in CRS offer some novel insights into the pathogenesis of this disease. In addition, existing treatment options targeting disorder of sinonasal epithelium can help to relieve the main symptoms associated with CRS to some extent.

Conclusion

The presence of a normal epithelium is fundamental for maintaining homeostasis in the nasal and paranasal sinuses. Here, we describe various aspects of the sinonasal epithelium and highlight the contributions of epithelial dysfunction to CRS pathogenesis. Our review provides sound evidence of the need for in-depth study of the pathophysiological alterations of this disease and for the development of novel epithelium-targeting alternative treatments.