Vitamin D deficiency is associated with increased human sinonasal fibroblast proliferation in chronic rhinosinusitis with nasal polyps

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.

The Effect of Vitamin D Supplement on the Relapsing Incidence of Rhinosinusitis with Nasal Polyposis after Fuctional Endoscpoic Sinus Surgery

Background

Nasal polyp (NP) is the most common benign tumor that can cause nasal obstruction and more annoying problems in patients. Recently, investigators have been focusing on complementary therapies alone or in conjunction with endoscopic nasal and sinus surgery. However, given the association of Vitamin D (VD) deficiency and chronic rhinosinusitis with nasal polyposis (CRSwNP) in previous studies, it may be possible to prevent the recurrence of NP and the development of rhinosinusitis by controlling serum levels of VD and maintaining it at a normal level. The current study aimed to investigate the efficacy of VD supplementation in preventing CRSwNP recurrence after endoscopic surgery.

Materials and Methods

This clinical trial composed of vitamin D deficient patients with CRSwNP who were candidates for endoscopic sinus surgery in two groups of cases and controls. After endoscopic sinus surgery for all patients, we administered VD supplementation (50,000 IU) once a week for 8 weeks for cases and no further intervention for controls. The severity of symptoms was assessed using Sino-nasal outcome test (SNOT-22) and NP recurrence and recorded pre- and postintervention.

Results

The findings indicated a higher mean change of SNOT-22 in the case group compared to that of the control group (36.03 ± 10.71 vs. 29.90 ± 11.99; P = 0.041). Moreover, the percentage of NP recurrence in cases was lower than controls; so that receiving VD supplementation has significantly reduced the chance of NP recurrence (odd ratio [95% confidence interval]: 0.298 [0.099-0.900]; P = 0.032).

Conclusion

According to the result of the study, the administration of VD supplementation after endoscopic sinus surgery can reduce the severity of CRSwNP symptoms and NP recurrence significantly.

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

In patients with chronic rhinosinusitis with nasal polyps, primary human sinonasal epithelial cell (HSNEC) 1α-hydroxylase levels are reduced, as is their ability to metabolize 25-hydroxycholecalciferol [25(OH)D₃] to its active metabolite, 1α,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃]. In this study, we sought to identify the factor responsible for the regulation of HSNEC metabolism of 25(OH)D₃, focusing on C3 and C3a. Multiple inhaled irritants trigger the release of complement components, C3 and C3a, leading to suppression of 1α-hydroxylase levels in HSNECs. Recombinant C3a was able to decrease 1α-hydroxylase and impair 25(OH)D₃ to 1,25(OH)₂D₃ metabolism, while addition of a C3a receptor antagonist restored conversion. Conversely, 1,25(OH)₂D₃ suppressed Aspergillus fumigatus-induced C3 and C3a levels in HSNEC supernatant. Given the ability of 1,25(OH)₂D₃ to modulate LL37 in other cell types, we examined its regulation in HSNECs and relationship to C3a. 1,25(OH)₂D₃ stimulated the secretion of LL37, whereas A. fumigatus and C3a suppressed it. Conversely, LL37 reduced the release of C3/C3a by HSNECs. Lastly, oral steroid use and in vitro dexamethasone application both failed to increase 1α-hydroxylase or reduce C3a levels. In summary, in this article, we describe for the first time a novel relationship between complement activation and local vitamin D metabolism in airway epithelial cells. The presence of elevated C3/C3a in patients with asthma and/or chronic rhinosinusitis with nasal polyps may account for their impaired HSNEC 25(OH)D₃ to 1,25(OH)₂D₃ metabolism and explain why they receive limited therapeutic benefit from oral vitamin D₃ supplementation.

Role of Vitamin D in the Clinical Course of Nasal Polyposis

Vitamin D is a lipo-soluble hormone well known for its effects on calcium homeostasis and bone metabolism. Recently, there has been growing interest in the extraskeletal effects of vitamin D. In particular, recent studies have highlighted how vitamin D plays a fundamental role in immunomodulation processes in the context of both innate and adaptive immunity, with consequent anti-inflammatory and anti-oxidant effect in different immune-mediated pathologies, such as systemic sclerosis, psoriasis, atopic dermatitis and rheumatoid arthritis; as well as in various pro-inflammatory processes affecting the airways, including chronic rhinosinusitis with (CRSwNP) or without (CRSsNP) nasal polyposis. We analyze the role of vitamin D in the genesis and progression of CRSwNP/sNP and its supplementation as a safe and valid therapeutic strategy capable of improving the clinical outcome of standard therapies.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

I.

EXECUTIVE SUMMARY

BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document.

METHODS

ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary.

RESULTS

ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided.

CONCLUSION

This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.

The Immunomodulatory Role of Vitamin D in Respiratory Diseases

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The growing interest in the new role of vitamin D, particularly as an immunomodulatory factor, has spurred basic research and the development of clinical trials to better understand the influence of supplementation on various diseases. Vitamin D is an important nutrient factor in human health due to its role in calcium metabolism regulation, cellular growth, differentiation and its fundamental discovered activity in immune functions. It has influenced different diseases, particularly inflammatory and autoimmune diseases, through immune response regulation, modulating innate and adaptive immunity.

:

The aim of this review was to explore the role of vitamin D in the main respiratory diseases in children such as asthma, chronic rhinosinusitis, cystic fibrosis and recurrent respiratory infections.

Association between serum vitamin D and chronic rhinosinusitis: a meta-analysis

Introduction

Chronic rhinosinusitis is a highly heterogeneous chronic inflammation of the upper respiratory tract caused by immune dysfunction in human beings. However, the underlying etiology of this disease has not yet been well established. Several trials have revealed that serum vitamin D level abnormality might play a role in the pathophysiology of chronic rhinosinusitis.

Objective

The aim of present study was to perform a meta-analysis of studies to compare the serum vitamin D levels between patients with chronic rhinosinusitis and healthy controls and to evaluate the potential associations of serum vitamin D level with the occurrence of chronic rhinosinusitis.

Methods

Following the PRISMA guidelines, relevant databases incorporating Pubmed, Web of Science, Embase and Cochrane Library were searched from inception to December 1, 2018. Funnel plot symmetry and Egger’ test were used to detect publication biases. The outcomes were presented as Weighted Mean Difference combined with 95% Confidence Intervals to estimate the difference of serum vitamin D levels between patients with chronic rhinosinusitis and controls. Higgins I² value was used to test for heterogeneity between the included studies.

Results

Out of 176 studies, only eight studies involving 337 chronic rhinosinusitis patients and 179 healthy controls met the criteria and were included in the meta-analysis. In a pooled analysis of the studies, chronic rhinosinusitis patients showed decreased serum vitamin D status (WMD = −7.80, 95% CI −13.28 to −2.31, p = 0.000). Subgroups analyses based on study location (USA vs. Non-USA), types of biomarkers (25(OH)D3 vs. 25(OH)D) and the study design methods (retrospective vs. prospective) did not reveal heterogeneity. However, phenotypes of chronic rhinosinusitis, with versus without polyposis might account for some degree of heterogeneity. Meanwhile, a lower serum vitamin D level was observed in chronic rhinosinusitis with nasal polyps patients.

Conclusion

Our findings indicate that serum vitamin D level might be associated with patients with chronic rhinosinusitis as we detected a significant association between lower serum vitamin D status and chronic rhinosinusitis, especially in chronic rhinosinusitis with nasal polyps patients. However, further comprehensive studies are warranted in order to draw firm conclusions.

Vitamin D deficiency are associated with subjective disease severity in Chinese patients with chronic rhinosinusitis with nasal polyps

OBJECTIVE

To evaluate the serum vitamin D level in patients with chronic rhinosinusitis with nasal polyps and its correlation with the disease severity.

SETTING

Hospital of Zhejiang University.

STUDY DESIGN

Retrospective analysis of collected data.

SUBJECTS AND METHODS

Patients with chronic rhinosinusitis with or without nasal polyps who underwent endoscopic sinus surgery were recruited. Demographic information including age, gender, body mass index, smoke history, atopic status and asthma was collected. Disease severity was measured by the Lund-Mackay CT score and Sino-Nasal Outcome Test-22 score. Serum 25-hydroxyvitamin D3 was measured by enzyme-linked immunosorbent assay preoperatively.

RESULTS

Serum 25-hydroxyvitamin D3 levels were significantly lower in patients with nasal polyps (CRSwNP, 38.2 ± 9.1 nmol/L; CRSsNP, 48.94 ± 12.1 nmol/L; control, 54.1 ± 17.1 nmol/L. p < 0.001), and the levels were significantly associated with the preoperative Sino-Nasal Outcome Test-22 score (p = 0.013), but not with the Lund-Mackay score (p = 0.126). Furthermore, serum 25-hydroxyvitamin D3 levels were associated with the subjective improvement six months postoperatively (p < 0.001), CONCLUSION: Serum 25-hydroxyvitamin D3 levels are lower in Chinese CRSwNP patients. These 25-hydroxyvitamin D3 levels are associated with SNOT-22 score. Preoperative 25-hydroxyvitamin D3 level may impact on the symptom improvement after surgery.

Role of Vitamin D and Its Receptors in the Pathophysiology of Chronic Rhinosinusitis

OBJECTIVES

Chronic rhinosinusitis (CRS) is a disease that represents a challenging therapeutic problem. Vitamin D and its receptors (VDR) are involved in the regulation of the immune system and may play role in CRS. Objectives of this study were to assess the relationships between the total concentration of vitamin D (25VD3) in sera, vitamin D receptor (VDR) expression, 1α-hydroxylase expression, and clinical data, including age, gender, Sino-Nasal Outcome Test (SNOT-22), computerized tomography (CT) scan, allergy status, and vitamin D supplementation in CRS patients with (CRSwNP) and without nasal polyps (CRSsNP), and in a control group.

METHODS

The studied group comprised 52 patients with CRS without nasal polyps (sNP), 55 with CRS with nasal polyps (wNP), and 59 in the control group. The endpoints were determined by appropriate methods. We conducted immunohistochemical staining of gathered tissue from the ostiomeatal complex for determination of VDR and 1α-hydroxylase. Analytical results were compared with clinical data as already noted.

RESULTS

A decrease in VDR nuclear staining occurred in CRS patients as compared to controls. Insignificant differences were observed in 1α-hydroxylase, expression in all studied groups, while VDR and cytochrome CYP27B1 protein expression (1α-hydroxylase) correlated with clinical data.

CONCLUSIONS

The data provide evidence that indicates that vitamin D and its receptor and enzymes may play a role in CRS.

Lack of vitamin D signalling per se does not aggravate cardiac functional impairment induced by myocardial infarction in mice

Epidemiological studies have linked vitamin D deficiency to an increased incidence of myocardial infarction and support a role for vitamin D signalling in the pathophysiology of myocardial infarction. Vitamin D deficiency results in the development of secondary hyperparathyroidism, however, the role of secondary hyperparathyroidism in the pathophysiology of myocardial infarction is not known. Here, we aimed to explore further the secondary hyperparathyroidism independent role of vitamin D signalling in the pathophysiology of myocardial infarction by inducing experimental myocardial infarction in 3-month-old, male, wild-type mice and in mice lacking a functioning vitamin D receptor. In order to prevent secondary hyperparathyroidism in vitamin D receptor mutant mice, all mice were maintained on a rescue diet enriched with calcium, phosphorus, and lactose. Surprisingly, survival rate, cardiac function as measured by echocardiography and intra-cardiac catheterisation and cardiomyocyte size were indistinguishable between normocalcaemic vitamin D receptor mutant mice and wild-type controls, 2 and 8 weeks post-myocardial infarction. In addition, the myocardial infarction-induced inflammatory response was similar in vitamin D receptor mutants and wild-type mice, as evidenced by a comparable upregulation in cardiac interleukin-1-β and tumor-necrosis-factor-α mRNA abundance and similar elevations in circulating interleukin-1-β and tumor-necrosis-factor-α. Our data suggest that the lack of vitamin D signalling in normocalcaemic vitamin D receptor mutants has no major detrimental effect on cardiac function and outcome post-myocardial infarction. Our study may have important clinical implications because it suggests that the secondary hyperparathyroidism induced by vitamin D deficiency, rather than the lack of vitamin D signalling per se, may negatively impact cardiac function post-myocardial infarction.

Nasal polyp fibroblasts modulate epithelial characteristics via Wnt signaling

BACKGROUND

While essential to the normal differentiation of ciliated airway epithelial cells, upregulated Wnt signaling in chronic rhinosinusitis with nasal polyps (CRSwNP) has been proposed to result in abnormal epithelial morphology and dysfunctional mucociliary clearance. The mechanism of epithelial Wnt signaling dysregulation in CRSwNP is unknown, and importantly cellular sources of Wnt ligands in CRSwNP have not yet been investigated.

METHODS

Human sinonasal epithelial cells (hSNECs) and human sinonasal fibroblasts (hSNFs) were collected from 34 human subjects (25 control and 9 CRSwNP) and differentiated as primary air-liquid interface (ALI) and organoid co-cultures. hSNECs were isolated to the apical compartment of the transwell and hSNFs were isolated to the basolateral compartment. After 21 days of ALI culture, ciliary expression and sinonasal epithelial morphology were examined by immunohistochemistry (IHC) and quantitative real-time polymerase chain reaction (qRT-PCR). An organoid model was used to evaluate proliferation of basal cells in presence of hSNFs.

RESULTS

Epithelial cells co-cultured with CRSwNP-hSNFs revealed significantly decreased ciliated cells, altered epithelial cell morphology, and increased colony forming efficiency compared to epithelial cells co-cultured with control-hSNFs. CRSwNP-hSNFs showed significantly higher messenger RNA (mRNA) expression of canonical WNT3A. A Wnt agonist, CHIR99021, replicated CRSwNP-hSNF co-cultures, and treatment with the Wnt inhibitor IWP2 prevented abnormal morphologies.

CONCLUSION

These results suggest that abnormal interactions between epithelial cells and fibroblasts may contribute to CRSwNP pathogenesis and supports the concept that dysregulated Wnt signaling contributes impairment to epithelial function in CRSwNP.

Is there an association between vitamin D deficiency and adenotonsillar hypertrophy in children with sleep-disordered breathing?

BACKGROUND

Low vitamin D levels have been linked to the risk of sleep-disordered breathing (SDB) in children. Although adenotonsillar hypertrophy (ATH) is the major contributor to childhood SDB, the relationship between ATH and serum vitamin D is uncertain. We therefore investigated the relationship between vitamin D levels and associated factors in children with ATH.

METHODS

We reviewed data from all children with SDB symptoms who were treated from December 2013 to February 2014. Of these, 88 children whose serum vitamin D levels were measured were enrolled in the study. We divided the children into four groups based on adenoidal and/or tonsillar hypertrophy. We conducted a retrospective chart review to analyze demographic data, the sizes of tonsils and adenoids, serum 25-hydroxy-vitamin D [25(OH)D] level, body mass index (BMI), and allergen sensitization patterns.

RESULTS

Children in the ATH group had a lower mean 25(OH)D level than did those in the control group (p < 0.05). Children with vitamin D deficiencies exhibited markedly higher frequencies of adenoidal and/or tonsillar hypertrophy than did those with sufficient vitamin D (p < 0.05). Spearman's correlation analysis identified an inverse correlation between serum 25(OH)D levels and age, tonsil and adenoid size, and height (all p < 0.05). In a multiple regression analysis, tonsil and adenoid size as well as BMI-z score, were associated with 25(OH)D levels after controlling for age, sex, height, and mite sensitization (p < 0.05).

CONCLUSIONS

Our results suggest that low vitamin D levels are linked to ATH. Both the sizes of the adenoids and tonsils and the BMI-z score were associated with the 25(OH)D level. Therefore, measurement of the serum 25(OH)D level should be considered in children with ATH and SDB symptoms.

Glucocorticoid receptor isoform expression in peripheral blood mononuclear leukocytes of patients with chronic rhinosinusitis

BACKGROUND

In several inflammatory disorders, altered peripheral blood mononuclear leukocyte (PBML) glucocorticoid (GC) receptor isoform expression has been associated with GC resistance and disease severity. However, it is unclear if PBML GC receptor isoforms are expressed differentially and are associated with worsened disease severity in chronic rhinosinusitis (CRS).

METHODS

PBMLs were isolated from control (n = 8), CRS without nasal polyps (CRSsNP) (n = 8), atopic CRS with nasal polyps (CRSwNP) (n = 8), non-atopic CRSwNP (n = 8), and allergic fungal rhinosinusitis (AFRS) (n = 8) patients. Demographics, atopic status, asthmatic status, 22-item Sino-Nasal Outcome Test (SNOT-22) scores, Lund-Kennedy nasal endoscopy scores, Lund-Mackay sinus computed tomography (CT) scores, Kennedy Osteitis scores, and GC utilization 6 months postoperatively were collected. Intracellular immunostaining was then performed for functional GC receptor α (GCRα) and nonfunctional GC receptor β (GCRβ), followed by flow cytometry analysis of geometric mean fluorescent intensity (MFI) and the percentage of cells expressing each GC receptor isoform.

RESULTS

Compared to controls, each CRS subtype had decreased PBML GCRα and GCRα:GCRβ MFI expression, but no difference in GCRβ expression. Decreasing PBML GCRα in AFRS was associated with increasing Lund-Mackay sinus CT scores (r = -0.880, p =0.004). No significant associations were found between GC receptor isoform expression and other clinical measures.

CONCLUSION

CRS patients have reduced functional PBML GCRα expression and decreased GCRα:GCRβ compared to controls. Reductions in GCRα in AFRS are associated with worsening Lund-Mackay sinus CT scores. The clinical implications of decreased functional GC receptor expression merits further investigation.

[The influence of the vitamin D3 level in the blood serum of lactase gene polymorphism on the development of chronic polypous rhinosinusitis]

The objective of the present study was to elucidate the possible correlations between the vitamin D₃ level in the blood serum and lactase gene polymorphism (LCT-13910 T>C) in the patients presenting with chronic polypous rhinosinusitis (CPRS). The study included 50 patients with this condition and 14 subjects comprising the control group. The variants of lactase gene polymorphism (LCT-13910 T>C) were identified with the use of polymerase chain reaction (PCR) in real time. The total level of serum vitamin D₃ (VD₃) was determined by means of the immunochemical analysis (the electrochemiluminescence technique). In the group of patients presenting with chronic polypous rhinosinusitis, the level of VD₃ in the blood serum ranged from 48 nm/l to 85 nm/l (mean 60 nm/l) compared with that in the patients of the control group (from 78 nm/l to 112 nm/l; mean 97 nm/l) . The level of vitamin D₃ 'below the normal values' was documented in 71% of the patients with CPRS in comparison with 7% in the control subjects. Lactase gene polymorphism (LCT-13910 CC, CT) suggesting pronounced and latent hypolactasia was identified in 94% of the patients with CPRS compared with 78.6% in the control group. The occurrence of the CC genotype in the patients of both study groups was virtually identical: 52% in the patients presenting with chronic polypous rhinosinusitis and 57% in the control group. CT polymorphism was identified in 42% of the patients with CPRS and in 21% of the control subjects. The significant difference between the patients of the two groups was documented for the occurrence of TT polymorphism: 6% among the patients with CPRS and 21% in the controls (i.e. much higher in the healthy subjects). There was no significant difference between the serum levels of vitamin D₃ either among the patients with CPRS having LCT-13910 gene polymorphisms (CC, CT, TT) or among the control subjects. It is concluded that the study revealed the higher levels of vitamin D₃ in the blood sera from the control subjects in comparison with that in the patients with chronic polypous rhinosinusitis. Moreover, the patients of the latter group more frequently exhibited the variant of the LCT CT-13910 gene polymorphism suggesting latent hypolactasia whereas the subjects comprising the control group more frequently had the variant of the LCT CT-13910 gene polymorphism indicative of the normal tolerance of lactose.

Vitamin D3 Deficiency and its Association with Nasal Polyposis in Patients with Cystic Fibrosis and Patients with Chronic Rhinosinusitis

Background

Currently vitamin D3 (VD3) or cholecalciferol is considered an immunomodulator that may be implicated in nasal polyposis (NP) pathophysiology.

Objectives

This study aimed to investigate if deficiency of VD3 is associated with the presence of NP in patients with cystic fibrosis (CT) and patients with chronic rhinosinusitis (CRS).

Methods

In total, 152 adult participants were included in five phenotypic groups: CT with NP (CTwNP) (n = 27), CT without NP (CTsNP) (n = 31), CRS with NP (CRSwNP) (n = 32), CRS without NP (CRSsNP) (n = 30), and controls (n = 32). The serum levels of 25(OH)-VD3 <20 ng/mL are considered as a deficiency, 21–29 ng/mL as insufficiency, and >30 ng/mL as sufficiency. Endoscopic and imaging staging of the mucosal disease performed with the Lund-Kennedy (LK) and Lund-Mackay (LM) scoring systems, respectively. The genotype of the patients with CT and the nasal microbial colonization of the patients with CT and patients with CRS were also recorded.

Results

The patients with CTwNP had the lowest percentage of sufficiency in VD3 and the highest percentage in insufficiency among all the groups. The LM imaging scores were inversely correlated with the VD3 levels in both arms of the study (CT and CRS). Moreover, the LK endoscopic scores had a similar correlation in the CT groups; however, this was not the case with the CRS groups. The genotype of the patients with CT was not correlated with the VD3 serum levels. The patients with positive microbial colonization (mainly Pseudomonas and Staphylococcus aureus) had significantly lower VD3 serum levels in both the CT and CRS process.

Conclusion

VD3 deficiency seemed to be associated with the presence of nasal polyps in the patients with CRS and in the patients with CT in a similar manner. The lower the level of serum VD3, the more severe the mucosal disease was found in the imaging studies and the more frequent microbial colonization of the patients with CT and the patients with CRS.

Dietary vitamin D3 deficiency exacerbates sinonasal inflammation and alters local 25(OH)D3 metabolism

RATIONALE

Patients with chronic rhinosinusitis with nasal polyps (CRSwNP) have been shown to be vitamin D3 (VD3) deficient, which is associated with more severe disease and increased polyp size. To gain mechanistic insights into these observational studies, we examined the impact of VD3 deficiency on inflammation and VD3 metabolism in an Aspergillus fumigatus (Af) mouse model of chronic rhinosinusitis (Af-CRS).

METHODS

Balb/c mice were fed control or VD3 deficient diet for 4 weeks. Mice were then sensitized with intraperitoneal Af, and one week later given Af intranasally every three days for four weeks while being maintained on control or VD3 deficient diet. Airway function, sinonasal immune cell infiltrate and sinonasal VD3 metabolism profiles were then examined.

RESULTS

Mice with VD3 deficiency had increased Penh and sRaw values as compared to controls as well as exacerbated changes in sRaw when coupled with Af-CRS. As compared to controls, VD3 deficient and Af-CRS mice had reduced sinonasal 1α-hydroxylase and the active VD3 metabolite, 1,25(OH)2D3. Differential analysis of nasal lavage samples showed that VD3 deficiency alone and in combination with Af-CRS profoundly upregulated eosinophil, neutrophil and lymphocyte numbers. VD3 deficiency exacerbated increases in monocyte-derived dendritic cell (DC) associated with Af-CRS. Conversely, T-regulatory cells were decreased in both Af-CRS mice and VD3 deficient mice, though coupling VD3 deficiency with Af-CRS did not exacerbate CD4 or T-regulatory cells numbers. Lastly, VD3 deficiency had a modifying or exacerbating impact on nasal lavage levels of IFN-γ, IL-6, IL-10 and TNF-α, but had no impact on IL-17A.

CONCLUSIONS

VD3 deficiency causes changes in sinonasal immunity, which in many ways mirrors the changes observed in Af-CRS mice, while selectively exacerbating inflammation. Furthermore, both VD3 deficiency and Af-CRS were associated with altered sinonasal VD3 metabolism causing reductions in local levels of the active VD3 metabolite, 1,25(OH)2D3, even with adequate circulating levels.