Major secretory mucin expression in chronic sinusitis

Ultra-simple nucleic acid extraction using a polystyrene microplastic particles-thermal lysis system for rapid detection of pathogen in nasal mucus

Respiratory infections are a leading cause of death and disability globally and have become an important issue of public concern. Nucleic acid amplification test (NAAT) has been recognized as the gold standard for respiratory infection diagnosis, and played a critical role in epidemic control during the COVID-19 pandemic. However, the laborious nucleic acid extraction limits the application of NAAT in the on-site respiratory infection diagnosis, an effective approach for disease control and prevention. Herein, a polystyrene microplastic particle (PSMP)-thermal lysis system was established to extract nucleic acids from nasal mucus in 4 min simply and rapidly without sacrificing sensing performance. The PSMP-thermal lysis system showed a strong protein adsorption capacity, by which nearly eliminating the interference of protein content in nasal mucus on amplification reaction. Moreover, the PCR using this PSMP-thermal lysis system showed excellent selectivity and anti-jamming ability, as well as the high sensitivity comparable to that using commercial kits based on commonly used solid-phase extraction in detecting target pathogens in sticky nasal mucus with protein content of 25.11 μg/μL. Furthermore, the practical use investigation indicated the PCR assay using this system could accurately identify respiratory infection patients by detecting corresponding pathogens in clinical nasal mucus samples. This PSMP-thermal lysis system has the potential for pathogen detection in various respiratory secretions and is anticipated to substantially simplify molecular diagnosis of respiratory infections.

Mucus and mucin: changes in the mucus barrier in disease states

In this review we discuss mucus, the viscoelastic secretion from goblet or mucous producing cells that covers and protects all non-keratinized wet epithelial surfaces. In addition to the surface of organs directly contacting with the external environment such as the eyes, this layer provides protection to the underlying gastrointestinal, respiratory and female reproductive tracts by trapping pathogens, irritants, environmental fine particles and potentially harmful foreign substances. Mucins, the primary structural components of mucus, form structurally different mucus layers at different sites in a process regulated by a variety of factors. Currently, more and more studies have shown that the mucus barrier is not only closely related to various intestinal mucus diseases, but also involved in the occurrence and development of various airway diseases and mucus-related diseases, thus it may become a new target for the treatment of various related diseases in the future. Since the dysfunction of the mucous layer is closely related to various pathological processes, in-depth understanding of its molecular mechanism and physiological role is of great theoretical and practical significance for disease prevention and treatment. Here, we discuss different aspects of the mucus layer by focusing on its chemical composition, synthetic pathways, and some of the characteristics of the mucus layer in physiological and pathological situations.

Systematic Review of Protein Biomarkers in Adult Patients With Chronic Rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous condition characterized by differing inflammatory endotypes. The identification of suitable biomarkers could enable personalized approaches to treatment selection.

OBJECTIVE

This study aimed to identify and summarize clinical studies of biomarkers in adults with CRS in order to inform future research into CRS endotypes.

METHODS

We conducted systematic searches of MEDLINE and Web of Science from inception to January 30, 2022 and included all clinical studies of adult CRS patients and healthy controls measuring biomarkers using enzyme-linked immunosorbent assays or Luminex immunoassays. Outcomes included the name and tissue type of identified biomarkers and expression patterns within CRS phenotypes. Study quality was assessed using the National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies. A narrative synthesis was performed.

RESULTS

We identified 78 relevant studies involving up to 9394 patients, predominantly with CRS with nasal polyposis. Studies identified 80 biomarkers from nasal tissue, 25 from nasal secretions, 14 from nasal lavage fluid, 24 from serum, and one from urine. The majority of biomarkers found to distinguish CRS phenotypes were identified in nasal tissue, especially in nasal polyps. Serum biomarkers were more commonly found to differentiate CRS from controls. The most frequently measured biomarker was IL-5, followed by IL-13 and IL-4. Serum IgE, IL-17, pentraxin-3 and nasal phospho-janus kinase 2, IL-5, IL-6, IL-17A, granulocyte-colony stimulating factor, and interferon gamma were identified as correlated with disease severity.

CONCLUSION

We have identified numerous potential biomarkers to differentiate a range of CRS phenotypes. Future studies should focus on the prognostic role of nasal tissue biomarkers or expand on the more limited studies of nasal secretions and nasal lavage fluid.We registered this study in PROSPERO (CRD42022302787).

Analysis of Bacterial Biofilm Formation and MUC5AC and MUC5B Expression in Chronic Rhinosinusitis Patients

Chronic rhinosinusitis (CRS) is a condition affecting as much as 16% of the adult population in developed countries with many factors attributed to its development, including the more recently proposed role of bacterial biofilm infections. Plenty of research has been conducted on biofilms in CRS and the causes behind the development of such an infection in the nasal cavity and sinuses. One such probable cause is the production of mucin glycoproteins by the mucosa of the nasal cavity. To investigate the possible link between biofilm formation and mucin expression levels and their relationship with CRS etiology, we examined samples from 85 patients by means of spinning disk confocal microscopy (SDCM) to establish their biofilm status and quantitative reverse transcription polymerase chain reaction (qRT-PCR) to determine MUC5AC and MUC5B expression levels. We observed a significantly higher prevalence of bacterial biofilms in the CRS patient group compared to the control group. In addition, we detected higher expression levels of MUC5B but not MUC5AC in the CRS group, which suggested a possible role for MUC5B in CRS development. Finally, we found no direct relationship between biofilm presence and mucin expression levels, thereby showing a multifaceted connection between these two major factors implicated in CRS etiology.

The impact of Sambucus nigra L. extract on inflammation, oxidative stress and tissue remodeling in a rat model of lipopolysaccharide-induced subacute rhinosinusitis

Rhinosinusitis is a common disorder related to inflammation of paranasal sinuses and nasal cavity mucosa. Herbal medicines could be an option in the treatment of rhinosinusitis due to their anti-inflammatory and anti-oxidative properties. The study aims to investigate the effect of intranasal Sambucus nigra L. subsp. nigra (SN) extract against inflammation, oxidative stress, and tissue remodeling in nasal and sinus mucosa, but also in serum, lungs, and brain, in Wistar rat model of subacute sinonasal inflammation induced by local administration of lipopolysaccharides (LPS), from Escherichia Coli. The cytokines (TNF-α, IL-1β, IL-6) and oxidative stress (malondialdehyde) in nasal mucosa, blood, lungs, and brain were analyzed. In addition, a histopathological examination was performed, and NF-kB, MMP2, MMP9, TIMP1 expressions were also evaluated in nasal mucosa. Both doses of LPS increased the production of cytokines in all the investigated tissues, especially in the nasal mucosa and blood (p < 0.01 and p < 0.05), and stimulated their secretion in the lungs, and partially in the brain. Malondialdehyde increased in all the investigated tissues (p < 0.01 and p < 0.05). In parallel, upregulation of NF-kB and MMP2 expressions with downregulation of TIMP1, particularly at high dose of LPS, was observed. SN extract reduced the local inflammatory response, maintained low levels of IL-6, TNF-α, and IL-1β. In lungs, SN reduced all cytokines levels while in the brain, the protective effect was noticed only on IL-6. Additionally, SN diminished lipid peroxidation and downregulated NF-kB in animals exposed to a low dose of LPS, with increased TIMP1 expression, while in animals treated with a high dose of LPS, SN increased NF-kB, MMP2, and MMP9 levels. In conclusion, SN extract diminished the inflammatory response, reduced generation of reactive oxygen species (ROS) and, influenced MMPs expressions, suggesting the benficial effect of SN extract on tissue remodeling in subacute rhinosinusitis and on systemic inflammatory response.

The impact of Lactococcus lactis (probiotic nasal rinse) co-culture on growth of patient-derived strains of Pseudomonas aeruginosa

BACKGROUND

The Lactococcus strain of bacteria has been introduced as a probiotic nasal rinse for alleged salubrious effects on the sinonasal bacterial microbiome. However, data regarding interactions with pathogenic bacteria within the sinuses are lacking. The purpose of this study is to assess the interaction between L. lactis and patient-derived Pseudomonas aeruginosa, an opportunistic pathogen in recalcitrant chronic rhinosinusitis (CRS).

METHODS

Commercially available probiotic suspension containing L. lactis W136 was grown in an anaerobic chamber and colonies were isolated. Colonies were co-cultured with patient-derived P. aeruginosa strains in the presence of porcine gastric mucin (mimicking human mucus) for 72 hours. P. aeruginosa cultures without L. lactis served as controls. Colony forming units (CFUs) were compared.

RESULTS

Six P. aeruginosa isolates collected from 5 CRS patients (3 isolates from cystic fibrosis [CF], 1 mucoid strain) and laboratory strain PAO1 were co-cultured with L. lactis. There was no statistical difference in CFUs of 5 P. aeruginosa isolates grown with L. lactis compared to CFUs without presence of L. lactis. CFU counts were much higher when the mucoid strain was co-cultured with L. lactis (CFU+L.lactis = 1.9 × 108 ± 1.44 × 107, CFU-L.lactis = 1.3 × 108 ± 8.9 × 106, p = 0.01, n = 7). L. lactis suppressed the growth of 1 P. aeruginosa strain (CFU+L.lactis = 2.15 × 108 ± 2.9 × 107, CFU-L.lactis = 3.95 × 108 ± 4.8 × 106, p = 0.03, n = 7).

CONCLUSION

L. lactis suppressed the growth of 1 patient P. aeruginosa isolate and induced growth of another (a mucoid strain) in in vitro co-culture setting in the presence of mucin. Further experiments are required to assess the underlying interactions between L. lactis and P. aeruginosa.

A Comprehensive Systematic Review of the Association Between Airway Mucins and Chronic Rhinosinusitis

Objective

Airway mucins are the major constituents of mucus and one of the first lines of host defense against inhaled pathogens. However, aberrant expression of mucins is associated with mucus hypersecretion resulting in chronic nasal drainage, a common complaint from patients with chronic rhinosinusitis (CRS). Our goal in this systematic review was to determine (1) expression profiles, (2) regulatory mechanisms, and (3) the pathologic roles of mucins associated with CRS.

Methods

MEDLINE, Cochrane Library, Embase, Scopus, Web of Science, and ClinicalTrials.gov were searched for studies focused on the role of mucins in CRS. Quality was assessed using the Cochrane Risk of Bias tool. The full text articles selected were then categorized into 3 study groups: (1) clinical, (2) animal, and (3) in vitro cultures. Data regarding study design, population/setting, methods, and bias were extracted and synthesized.

Results

Our initial search generated 392 titles/abstracts. After the primary review, 111 articles underwent secondary review. The final review included 53 articles, including 34 articles (64%) in the clinical study group, 3 articles (6%) in the animal study group, and 16 articles (30%) in the in vitro study group. In total, aberrant expression of 8 mucins—6 secreted-mucins (MUC2, -5AC, -5B, -6, -7, and -8) and 2 membrane-bound mucins (MUC1 and -4)—were identified in CRS tissues compared to healthy controls. Mucin expression was associated with bacterial sinusitis, inflammatory markers, and the response to steroid therapy in patients with CRS with nasal polyposis.

Conclusion

There is a strong correlation between alterations in mucin expression profiles and CRS. This systematic review highlights the most recent literature on the role of mucins in CRS. The analysis of these studies is limited by the heterogeneity in study designs, relatively few numbers of clinical samples, and lack of mechanistic studies in animal models and in vitro cultures.

PepsinA as a Marker of Laryngopharyngeal Reflux Detected in Chronic Rhinosinusitis Patients

Objectives

We aimed to confirm the presence of pepsinA in the nasal secretions and tissues of chronic rhinosinusitis (CRS) patients and reveal the relationship between CRS and laryngopharyngeal reflux (LPR).

Study Design

Cross-sectional study.

Setting

The study was conducted at the Department of Oto-Rhino-Laryngology, West China Hospital, Sichuan University.

Subjects and Methods

A total of 32 CRS patients with or without nasal polyps (CRSwNP and CRSsNP, respectively) and 10 normal controls were enrolled in our study. We investigated the expression of pepsinA in the nasal tissues, secretions, and blood plasma from the subjects by immunohistochemical staining, Western blot, or ELISA. Additionally, the expressions of MUC4, MUC5AC, MUC5B, MUC8, and pepsinogenA in nasal tissue were evaluated by quantitative real-time polymerase chain reaction.

Results

Immunohistochemistry and Western blot revealed that the pepsinA expression levels in the turbinate mucosa in CRSwNP/CRSsNP patients, which were largely restricted to the epithelial layer or glandular mucous cells in nasal tissues, were significantly higher than those in controls and in the polyp tissues of CRSwNP patients ( P < .05). In addition, the concentration of pepsinA in nasal secretions was significantly increased in the CRSwNP (147.85 ± 53.69 ng/mL, P < .001) and CRSsNP (134.12 ± 36.23 ng/mL, P < .001) groups as compared with the controls (68.69 ± 19.28 ng/mL). Although MUC5AC, MUC5B, and MUC8 expression differed among the groups, no correlation between pepsinA and mucin genes was found.

Conclusion

The results of this study provided evidence of an association between LPR and CRS, although no correlation was found to exist between LPR and mucin genes in CRS patients.

Increased expression of hCLCA1 in chronic rhinosinusitis and its contribution to produce MUC5AC

OBJECTIVES/HYPOTHESIS

Mucus hypersecretion is a hallmarks of chronic rhinosinusitis. The expression of MUC5AC, a major respiratory mucin gene, is increased in chronic rhinosinusitis. The mechanisms inducing mucus hypersecretion have not been fully evaluated in chronic rhinosinusitis. Human Ca²⁺ -activated Cl- channel 1 (hCLCA1) is implicated in the regulation of mucus production, airway fluid, and electrolyte transport. The present study objectives was to investigate the expression of hCLCA1 in chronic rhinosinusitis and evaluate whether its level is altered by stimulation with type 1 T helper (Th1) and Th2 cytokines, and to determine the possible role of hCLCA1 on the regulation of mucin 5AC (MUC5AC) production.

STUDY DESIGN

Controlled prospective study.

METHODS

The expression of hCLCA1 and MUC5AC in normal and inflammatory ethmoid mucosa was determined by real-time polymerase chain reaction, immunohistochemistry, and Western blot. In cultured cells, the expression of hCLCA1 and MUC5AC was measured after stimulation with Th1 and Th2 cytokines. In a supernatant, the MUC5AC level was analyzed using enzyme-linked immunosorbent assay after treatment with niflumic acid.

RESULTS

The levels of hCLCA1 and MUC5AC were increased in chronic rhinosinusitis, irrespective of nasal polyp presence, where they were distributed in superficial epithelial cells and submucosal glands. In cultured cells treated with interleukin (IL)-9, IL-4, IL-13, tumor necrosis factor-α, transforming growth factor-β, interferon-γ, and IL-1β, the expression of hCLCA1 and MUC5AC was increased. In cells treated with niflumic acid, the production of MUC5AC was inhibited.

CONCLUSIONS

The current findings indicate that the expression of hCLCA1 is increased in chronic rhinosinusitis and may be regulated by Th1 and Th2 cytokines, possibly contributing to the production of MUC5AC.

LEVEL OF EVIDENCE

NA Laryngoscope, 126:E347-E355, 2016.

Exploring the role and diversity of mucins in health and disease with special insight into non-communicable diseases

Mucins are major glycoprotein components of the mucus that coats the surfaces of cells lining the respiratory, digestive, gastrointestinal and urogenital tracts. They function to protect epithelial cells from infection, dehydration and physical or chemical injury, as well as to aid the passage of materials through a tract i.e., lubrication. They are also implicated in the pathogenesis of benign and malignant diseases of secretory epithelial cells. In Human there are two types of mucins, membrane-bound and secreted that are originated from mucous producing goblet cells localized in the epithelial cell layer or in mucous producing glands and encoded by MUC gene. Mucins belong to a heterogeneous family of high molecular weight proteins composed of a long peptidic chain with a large number of tandem repeats that form the so-called mucin domain. The molecular weight is generally high, ranging between 0.2 and 10 million Dalton and all mucins contain one or more domains which are highly glycosylated. The size and number of repeats vary between mucins and the genetic polymorphism represents number of repeats (VNTR polymorphisms), which means the size of individual mucins can differ substantially between individuals which can be used as markers. In human it is only MUC1 and MUC7 that have mucin domains with less than 40% serine and threonine which in turn could reduce number of PTS domains. Mucins can be considered as powerful two-edged sword, as its normal function protects from unwanted substances and organisms at an arm's length while, malfunction of mucus may be an important factor in human diseases. In this review we have unearthed the current status of different mucin proteins in understanding its role and function in various non-communicable diseases in human with special reference to its organ specific locations. The findings described in this review may be of direct relevance to the major research area in biomedicine with reference to mucin and mucin associated diseases.

Increased expression of MUC5AC and MUC5B promoting bacterial biofilm formation in chronic rhinosinusitis patients

OBJECTIVE

Binding of bacteria to mucin and then colonizing is the first step of bacterial biofilm (BBF) formation in chronic rhinosinusitis (CRS) patients. Yet, information is sparse on how mucins effects on BBF formation. In this study, we aimed to investigate the relationship between mucin expression and the formation of BBF in CRS patients.

METHODS

Sinus mucosa were harvested from 24 patients undergoing endoscopic surgery for CRS. The positive of BBF formation were detected by scanning electronic microscopy (SEM) and the expression of MUC1, MUC2, MUC5AC, and MUC5B were determined by immunohistochemistry (IHC). The difference expression of mucins were analyzed between the BBF positive and negative cohorts in CRS patients.

RESULTS

MUC5AC and MUC5B are two major mucins in CRS mucosa with the former mainly restricted to the goblet cells of epithelium and the latter mainly restricted to the submucosal glands. Expression of MUC5AC and MUC5B in the sinus mucosa of BBF(+) CRS group was significantly higher than those in BBF(-) CRS group (p<0.05). For MUC1 and MUC2, no significant difference was found between the two groups (p>0.05).

CONCLUSION

Our study indicated that increased expression of MUC5AC and MUC5B may play an important role in the pathogenesis of BBF formation.

More than one disease process in chronic sinusitis based on mucin fragmentation patterns and amino Acid analysis

Objective. To characterise fragmentation patterns and amino acid composition of MUC2 and MUC5AC in chronic sinusitis. Methods. Antigenic identity of purified sinus mucins was determined by ELISA. Fragmentation patterns of a MUC5AC rich sample mucin were analysed by Sepharose CL-2B gel chromatography. Samples, divided into one MUC2 rich and one MUC5AC rich group, were subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and their amino acid contents were analysed. Results. Reduction, trypsin digestion, and papain digestion produced progressively smaller mucin species. On SDS-PAGE, digested MUC5AC rich mucin produced four distinct products. Amino acid analysis was characteristic of mucins with high serine, threonine, and proline contents and reduction and proteolysis increased relative proportions of these amino acids. MUC5AC rich mucins contained more protein than MUC2 rich mucins. Conclusion. Sinus mucin fragmentation produced mucin subunits and glycopeptide units of smaller molecular sizes which are likely to have lower viscoelastic properties. Applying this in vivo could alter mucus physical properties and biologic functions. Amino acid contents of MUC2 and MUC5AC mucins are different. This could be contributing to biological properties and functions of sinus mucins. These data suggest that there may be different pathological processes occurring at the cellular level on chronic sinusitis.

Hypoxia-mediated mechanism of MUC5AC production in human nasal epithelia and its implication in rhinosinusitis

Background

Excessive mucus production is typical in various upper airway diseases. In sinusitis, the expression of MUC5AC, a major respiratory mucin gene, increases. However, the mechanisms leading to mucus hypersecretion in sinusitis have not been characterized. Hypoxia due to occlusion of the sinus ostium is one of the major pathologic mechanisms of sinusitis, but there have been no reports regarding the mechanism of hypoxia-induced mucus hypersecretion.

Methods and Findings

This study aims to identify whether hypoxia may induce mucus hypersecretion and elucidate its mechanism. Normal human nasal epithelial (NHNE) cells and human lung mucoepidermoid carcinoma cell line (NCI-H292) were used. Sinus mucosa from patients was also tested. Anoxic condition was in an anaerobic chamber with a 95% N₂/5% CO₂ atmosphere. The regulatory mechanism of MUC5AC by anoxia was investigated using RT-PCR, real-time PCR, western blot, ChIP, electrophoretic mobility shift, and luciferase assay. We show that levels of MUC5AC mRNA and the corresponding secreted protein increase in anoxic cultured NHNE cells. The major transcription factor for hypoxia-related signaling, HIF-1α, is induced during hypoxia, and transfection of a mammalian expression vector encoding HIF-1α results in increased MUC5AC mRNA levels under normoxic conditions. Moreover, hypoxia-induced expression of MUC5AC mRNA is down-regulated by transfected HIF-1α siRNA. We found increased MUC5AC promoter activity under anoxic conditions, as indicated by a luciferase reporter assay, and mutation of the putative hypoxia-response element in MUC5AC promoter attenuated this activity. Binding of over-expressed HIF-1α to the hypoxia-response element in the MUC5AC promoter was confirmed. In human sinusitis mucosa, which is supposed to be hypoxic, expression of MUC5AC and HIF-1α is higher than in control mucosa.

Conclusion

The results indicate that anoxia up-regulates MUC5AC by the HIF-1α signaling pathway in human nasal epithelia and suggest that hypoxia might be a pathogenic mechanism of mucus hypersecretion in sinusitis.

Mucin gene expression in reflux laryngeal mucosa: histological and in situ hybridization observations

Objectives/Hypothesis. To determine if laryngopharyngeal reflux alters mucin gene expression in laryngeal mucosa. Methods. In situ hybridization was employed to study the expression of the 8 well-characterised mucin genes MUC1-4, 5AC, 5B, 6, and 7 in reflux laryngeal mucosa from laryngeal ventricles, posterior commissures, and vocal folds compared to control/normal laryngeal mucosa. Results. MUC1-5 genes are expressed in normal and reflux laryngeal mucosa. MUC1, 3 and 4 are expressed in respiratory and squamous mucosa whereas MUC2 and 5AC are expressed in respiratory mucosa only. MUC3, 4 and 5AC are downregulated in reflux mucosa. MUC5AC expression is significantly reduced in the 3 mucosal sites and when mucosal type was taken into account, this remains significant in combined laryngeal and ventricular mucosa only. Conclusions. MUC3, 4 and 5AC expression is downregulated in laryngopharyngeal reflux. This may be due to laryngeal mucosal metaplasia and/or alteration of mucin gene expression in the preexisting mucosa. Altered mucin gene expression might predispose laryngeal mucosa to the damaging effect of reflux.

Quadrupedal head position enhances recovery from chronic maxillary sinusitis

OBJECTIVES

The position of human maxillary ostia is high on their superomedial walls, which may be suboptimal for natural drainage. Human maxillary sinuses exhibit better passive drainage through their ostia when tilted anteriorly to mimic a quadrupedal head position. We all know that sufficient drainage is very important for the treatment of chronic rhinosinusitis (CRS). Chronic maxillary sinusitis (CMS) is the high incidence of CRS. The aim of this study was to investigate the efficacy of quadrupedal head position in patients with CMS.

METHODS

One hundred six patients diagnosed with CMS were enrolled. Patients were randomized to quadrupedal head position group and non-quadrupedal head position group for 6 weeks of treatment. Treatment outcomes were measured using 1) Lund-Mackay scoring system of pre-and post-treatment computer tomography (CT); and 2) Sinonasal Quality-of-Life (QoL) Survey completed at baseline and 6 weeks of therapy.

RESULTS

There were statistically significant differences in QoL scores and CT scores between quadrupedal head position group and non-quadrupedal head position group. The quadrupedal head position group had much more improvements in QoL scores and CT scores than that of non-quadrupedal head position group. One patient in the quadrupedal head position group required functional endoscopic sinus surgery (ESS) due to persistent symptoms, and nine patients in non-quadrupedal head position group needed ESS. There were less patients that required ESS in the quadrupedal head position group than in the non-quadrupedal head position group.

CONCLUSIONS

The improvements of QoL scores and CT scores were significantly better in the quadrupedal head position group than that in the non-quadrupedal head position group. Quadrupedal head position can be valuable adjuvant therapy for patients with CMS.

TRPV1 and TRPA1 stimulation induces MUC5B secretion in the human nasal airway in vivo

AIM

Nasal transient receptor potential vanilloid 1 (TRPV1) stimulation with capsaicin produces serous and mucinous secretion in the human nasal airway. The primary aim of this study was to examine topical effects of various TRP ion channel agonists on symptoms and secretion of specific mucins: mucin 5 subtype AC (MUC5AC) and B (MUC5B).

METHODS

Healthy individuals were subjected to nasal challenges with TRPV1 agonists (capsaicin, olvanil and anandamide), TRP ankyrin 1 (TRPA1) agonists (cinnamaldehyde and mustard oil) and a TRP melastatin 8 (TRPM8) agonist (menthol). Symptoms were monitored, and nasal lavages were analysed for MUC5AC and MUC5B, i.e. specific mucins associated with airway diseases. In separate groups of healthy subjects, nasal biopsies and brush samples were analysed for TRPV1 and MUC5B, using immunohistochemistry and RT-qPCR. Finally, calcium responses and ciliary beat frequency were measured on isolated ciliated epithelial cells.

RESULTS

All TRP agonists induced nasal pain or smart. Capsaicin, olvanil and mustard oil also produced rhinorrhea. Lavage fluids obtained after challenge with capsaicin and mustard oil indicated increased levels of MUC5B, whereas MUC5AC was unaffected. MUC5B and TRPV1 immunoreactivities were primarily localized to submucosal glands and peptidergic nerve fibres, respectively. Although trpv1 transcripts were detected in nasal brush samples, functional responses to capsaicin could not be induced in isolated ciliated epithelial cells.

CONCLUSION

Agonists of TRPV1 and TRPA1 induced MUC5B release in the human nasal airways in vivo. These findings may be of relevance with regard to the regulation of mucin production under physiological and pathophysiological conditions.

The expression of MUC5AC and MUC5B mucin genes in the mucosa of chronic rhinosinusitis and nasal polyposis

BACKGROUND

The aim of this study was to investigate the expression of MUC5AC and MUC5B messenger RNAs (mRNAs) and localization of these proteins in human sinus mucosa of chronic rhinosinusitis (CRS) and CRS with nasal polyposis (CRS/NP).

METHODS

Maxillary sinus ostia mucosa was harvested from patients undergoing endoscopic sinus surgery for CRS, CRS/NP, and non-CRS pathologies (control). Then, sinus mucosa was analyzed using reverse-transcription polymerase chain reaction to detect mRNA of MUC5AC and MUC5B. Hematoxylin and eosin staining and immunofluorescent staining were used to localize MUC5AC and MUC5B proteins in the sinus mucosa.

RESULTS

mRNAs of MUC5AC and MUC5B in the sinus mucosa of CRS and CRS/NP were significantly increased compared with that in normal sinus mucosa (p < 0.01), and no significant difference was found between the mucosa of CRS and that of CRS/NP (p > 0.05). MUC5AC protein was expressed mainly in the goblet cells, and MUC5B expression was located in the submucosal glands cells and the epithelia of sinus mucosa. ARPC in staining of MUC5AC and MUC5B were found no different between the CRS group and the CRS/NP group (p > 0.05), whereas they were significantly lower in the normal group compared with the other two groups, respectively (p < 0.05).

CONCLUSION

This study showed that MUC5AC and MUC5B mucin genes were up-regulated in sinus mucosa of CRS and CRS/NP. MUC5AC and MUC5B may play an important role in the pathogenesis of CRS and NP.

Localization and expression of MUC5B and MUC7 mucins in pediatric sinus mucosa

OBJECTIVES

The purpose of this study was to analyze the secretory cell population and distribution of MUC5B and MUC7 mucins in the sinus mucosa of pediatric patients with and without chronic rhinosinusitis (CRS).

METHODS

Sinus mucosal specimens were collected at surgery in a pediatric tertiary care facility. Histologic, immunohistochemical, and morphometric analyses were performed on sinus mucosa of 20 children with CRS and 7 children without CRS.

RESULTS

A significant increase in the area of submucosal glands was evident in the sinus mucosa of children with CRS as compared to controls. MUC5B and MUC7 mucins were expressed in the submucosal glands, as well as in goblet cells, in the sinus mucosa of both populations. No differences in MUC5B or MUC7 expression were observed when mucin expression was normalized to glandular area.

CONCLUSIONS

Children with CRS have an increased number of submucosal glands, indicating that glandular mucins contribute to mucus overproduction in CRS. MUC5B and MUC7 mucins, which have previously been considered only glandular mucins, are also expressed in goblet cells in the sinus mucosa.

Upper airway mucin gene expression: a review

INTRODUCTION

The gel-like properties of mucus depend primarily on its content of mucins. The protein backbones of mucins are encoded by mucin genes. Of the currently known 20 mucin genes that encode protein backbone of mucins, 16 have been identified in the airways.

METHOD

We explored the current knowledge about upper airway mucin expression in health and disease conditions using a Medline search. We have also studied upper airway mucin gene expression and compared our results with the results from other studies.

RESULTS

MUC5AC, MUC5B, and MUC2 are the principal gel-forming mucins secreted in the airway. However, the spectrum of mucin expression in chronic upper airway diseases such as nasal polyps, chronic sinusitis, middle ear effusion, and cystic fibrosis is generally wide and variable.

DISCUSSION

The wide spectrum of upper airway mucin expression is possibly caused by various anatomic and histologic features as well as physiologic and pathologic variables. These variables have not been fully explored yet, and the majority of airway mucin expression studies used small numbers of samples.

CONCLUSION

Studies including adequate numbers of samples (patients) are more likely to reveal a clearer profile and more precise expression patterns. Generating a clear profile of mucin expression patterns in health and disease requires the analysis of different variables, which can alter that expression. It is also essential to understand the various molecular mechanisms controlling mucin gene and protein expression. This could lead to the invention of novel therapeutic modalities to treat upper airway diseases.

Bibliography. Current world literature. Nose and paranasal sinuses

PURPOSE OF REVIEW

Patients with advanced head and neck cancer are being treated with chemo-radiotherapy, and life is being prolonged, with or without persistent disease, for longer than was previously. Hypercalcaemia may present in patients with advanced or disseminated head and neck cancer, and, as such, these patients may present to a larger variety of clinicians for advice concerning their symptoms and illness. Modes of presentation of hypercalcaemia and treatment strategies are reviewed.

RECENT FINDINGS

There were previously few large series of head and neck cancer patients diagnosed with hypercalcaemia, which may or may not have been related to their cancer being treated. Investigations, by way of blood/serum calcium level, may identify such patients. Patients with cancer-related hypercalcaemia have a poor prognosis, but many may respond temporarily to treatment when offered, with an improvement of their quality of life and death.

SUMMARY

Hypercalcaemia should and must be considered in all patients who have or possibly have a diagnosis of a head and neck cancer and who present unwell with symptoms of fatigue, lethargy and somnolence. Investigation must include serum calcium (corrected for serum albumin binding) and parathyroid hormone level. Patients may be treated by a combination of rehydration and bisulphonate therapy until the serum calcium is reduced to a level below 3 mmol/l. The majority of patients diagnosed with hypercalcaemia due to head and neck malignancy die of their diseases in the short term, but some may enjoy a prolongation of life with reasonable quality if diagnosed and treated aggressively.