Extensive interstitial collagen deposition on the basement membrane zone in allergic nasal mucosa

A review of recent advances in exosomes and allergic rhinitis

Allergic rhinitis is a chronic inflammatory disease of nasal mucosa caused by the presence of IgE after exposure to allergens, characterized by nasal irritation, hypersecretion of the nasal passages and sneezing, which frequently occurs in children and adolescents. There has been an increase in allergic rhinitis over the past few years due to air pollution. Exosomes have been discovered to be nano-sized vesicles, which contain a wide range of substances, including proteins and nucleic acids, numerous studies indicates that exosomes play a vital role in cells communication. Recently there have been more and more studies exploring the role of exosomes in allergic rhinitis. Therefore, here we will present a comprehensive review of the research on exosomes and their role in allergic rhinitis for the purpose of providing new understanding of potential value of exosomes applied to the treatment of allergic rhinitis.

Nasal lavage cytology and mucosal histopathological alterations in patients with rhinitis

Introduction

The extent of epithelial lesion in allergic and non-allergic rhinitis and its association with inflammatory changes in nasal lavage has not been clarified.

Objective

To verify the association between the inflammatory cells in the nasal lavage, epithelial lesion extent and basement membrane thickness, in the nasal mucosa of patients with rhinitis; to determine the cutoff point of the percentage of eosinophils in the nasal lavage associated with the atopic patients.

Methods

Patients with rhinitis and indication for septoplasty and (or) turbinectomy for turbinate hypertrophy were selected, and were submitted to allergy skin tests, nasal lavage with measurement of albumin and interleukin-8 levels, total and differential counting of cells, and mucosal histopathological analysis to determine the extent of epithelial lesion, and degree of basement membrane thickening.

Results

Fifty-six patients with a median age of 24.5 years and a diagnosis of allergic rhinitis (n = 36) and non-allergic rhinitis (n = 20) were studied. In atopic subjects, allergy skin tests were positive for Dermatophagoides pteronyssinus in 35 (97.0%) and Lolium perenne in 18 (50.0%). Atopic subjects showed a higher clinical score index of rhinitis compared to non-atopic ones. The total count of cells, neutrophils, and levels of albumin and IL-8 were not different in the nasal lavage of atopic and non-atopic subjects. The cutoff point for eosinophil count in nasal fluid for the distinction between allergic rhinitis and non-allergic rhinitis was 4%. Some degree of epithelial lesion was more frequent in allergic rhinitis (94%) than in non-allergic rhinitis (65%) patients. In the presence of basement membrane thickness, as a marker of remodeling, there was no difference in the nasal lavage of patients with allergic rhinitis and non-allergic rhinitis.

Conclusion

In this series, 4% was the cutoff point for the number of eosinophils in the nasal lavage, for atopy differentiation. Upper airway remodeling accessed by basement membrane thickness showed similar inflammatory cell infiltrate in the nasal lavage, regardless of the presence of atopy.

The Peculiar Pattern of Type IV Collagen Deposition in Epiretinal Membranes

Idiopathic epiretinal membranes are sheets of tissue that develop in the vitreoretinal interface. They are formed by cells and extracellular matrix, and they are considered the expression of a fibrotic disorder of the eye. Confocal and immunoelectron microscopy of the extracellular matrix of excised membranes, revealed high contents of type IV collagen. It was distributed within epiretinal membranes in basement membrane-like structures associated with cells and in interstitial deposits. In both cases, type IV collagen was always associated with type I collagen. Col IV was also coupled with Col VI and laminin. At high magnification, type IV collagen immunolabelling was associated with interstitial deposits and showed a reticular appearance due to the intersection of beaded microfilaments. The microfilaments are about 12 nm in diameter with interbead distance of 30-40 nm. Cells of the epiretinal membranes showed intracellular lysosome-like bodies heavily labeled for type IV collagen suggesting an active role in membrane remodeling. Hence, type IV collagen is not necessarily always associated with basement membranes; the molecular interactions that it may develop when not incorporated in basement membranes are still unknown. It is conceivable, however, that they might have implications in the progression of epiretinal membranes and other fibrotic disorders.

T-Helper Type 1-T-Helper Type 2 Shift and Nasal Remodeling after Fine Particulate Matter Exposure in a Rat Model of Allergic Rhinitis

Background

Exposure to fine particulate matter (particulate matter ≤2.5 μm [PM2.5]) increases the risk of allergic rhinitis (AR), but the underlying mechanisms remains unclear. Thus, we investigated the roles of T-helper (Th)1–Th2 cytokines and nasal remodeling after ambient PM2.5 exposure in a rat model of AR.

Methods

Female Sprague-Dawley rats were randomized into six groups: a negative control group, a group of healthy rats exposed to 3000 μg/m3 PM2.5, an ovalbumin (OVA) induced AR model, and three PM2.5-exacerbated AR groups exposed to three different concentrations (200, 1000, and 3000 μg/m3) of PM2.5 for 30 days via inhalation. Nasal symptoms, levels of Th1–Th2 cytokines, the degree of eosinophilia in nasal lavage fluid (NLF), and the messenger RNA (mRNA) expressions of transcription factors GATA-3 and T-bet in the nasal mucosa were measured in each individual rat. Hyperplasia of globet cells and collagen deposition were examined by histology.

Results

PM2.5 significantly increased the number of sneezes and nasal rubs in rats with AR. PM2.5 also significantly decreased interferon gamma and increased interleukin (IL) 4 and IL-13 expressions as well as the number of eosinophils in NLF. The mRNA expression of GATA-3 in the nasal mucosa of rats with AR was upregulated by PM2.5, whereas T-bet was significantly downregulated. Statistically significant differences in OVA-specific serum immunoglobulin E, goblet cell hyperplasia, collagen deposition, and transforming growth factor beta 1 levels were observed between the PM2.5-exacerbated AR groups and the AR model group.

Conclusion

Analysis of our data indicated that an increase in the immune response with Th2 polarization and the development of nasal remodeling may be the immunotoxic mechanisms behind the exacerbation of AR after exposure to PM2.5.

Increased expression of YKL-40 in mild and moderate/severe persistent allergic rhinitis and its possible contribution to remodeling of nasal mucosa

BACKGROUND

Prominent expression of YKL-40 has been associated with pathological conditions characterized by tissue remodeling. We determined the expression level and distribution pattern of YKL-40 in allergic nasal mucosa and evaluated the effect of YKL-40 on the proliferation and migration of fibroblasts, the production of the mediators related to tissue remodeling, and collagen production. Additionally, the cytokine-driven regulation of YKL-40 expression was evaluated in cultured epithelial cells.

METHODS

The expression of YKL-40 in normal, mild, and moderate/severe allergic nasal mucosa was evaluated using real-time polymerase chain reaction (PCR), Western blot, and immunohistochemistry. Fibroblast migration was observed using a scratch wound method, and proliferation was determined by the MTT methods. Expression of proteoglycans, transforming growth factor (TGF) beta1, MMP2, MMP9, TIMP1, TIMP2, and collagen concentration were analyzed in fibroblasts treated with YKL-40. The expression levels of YKL-40 in cultured epithelial cells were examined after stimulation with mediators including Th2 cytokines, interferon (IFN)gamma, and TNF-alpha with real-time PCR and ELISA.

RESULTS

The expression of YKL-40 was up-regulated in allergic rhinitis and distributed in superficial epithelium, submucosal glands, and vascular endothelium, in addition to infiltrating cells. TGF-beta1, TIMP1, MMP9, and biglycan were up-regulated in fibroblasts on stimulation with YKL-40, accompanying increased proliferation and migration, and collagen production. IL-13, IFN-gamma, and TNF-alpha induced the increased production of YKL-40 in cultured epithelial cells.

CONCLUSION

YKL-40 is up-regulated in mild and moderate/severe persistent allergic rhinitis, and its expression can be regulated differentially by different cytokines, possibly contributing to the remodeling of nasal mucosa in allergic rhinitis.

Extra domain-A fibronectin is necessary for the development of nasal remodeling in chronic allergen-induced rhinitis

BACKGROUND

Extra domain A-containing fibronectin (EDA-FN) is necessary for the development of allergen-induced lower airway fibrosis. The pathogenesis of fibrosis in allergic rhinitis has not been well studied.

OBJECTIVES

To determine whether EDA-fibronectin is necessary for the development of nasal remodeling in a murine model of chronic allergic rhinitis and in human allergic rhinitis.

METHODS

EDA(-/-) and wild-type (WT) C57Bl/6 mice were sensitized intraperitoneally and then challenged with inhaled ovalbumin (OVA) or saline for 2 and 5 weeks. Clinical signs of rhinitis and histological analysis of nasal tissue were evaluated. Immunohistological staining for EDA-FN was performed in human tissue of inferior nasal conchae from patients with allergic rhinitis and controls.

RESULTS

After 2 weeks of allergen exposure, only goblet cell hyperplasia and perivascular eosinophilia were observed. After 5 weeks, goblet cell number, thickening of the subepithelial layer, and extent and area of collagen deposition were increased in the nasal tissue of WT OVA (ovalbumin)-challenged mice as compared with saline controls (P < .0001, P < .0001, P = .018, and P = .03, respectively). Clinical signs of rhinitis were observed only in WT OVA-challenged mice. In the EDA(-/-) mice exposed to OVA, collagen deposition, collagen area, and subepithelial thickness showed no increase and were similar to saline control mice, whereas goblet cell hyperplasia was similar to WT OVA-challenged mice. EDA-FN expression was prominent in inferior conchae from patients with allergic rhinitis but was absent in control patients.

CONCLUSION

EDA-containing fibronectin is necessary for the development of nasal tissue fibrotic remodeling process in both murine and human allergic rhinitis.

Safety, Tolerability, and Exposure of Ciclesonide Nasal Spray in Healthy and Asymptomatic Subjects With Seasonal Allergic Rhinitis

Ciclesonide is an intranasal corticosteroid in development for the treatment of allergic rhinitis. To assess the safety, tolerability, and pharmacokinetics of ciclesonide, adult healthy volunteers and asymptomatic subjects with seasonal allergic rhinitis were randomized to receive intranasal ciclesonide or placebo for 14 days. Serum concentrations of ciclesonide and its active metabolite, desisobutyryl-ciclesonide, were measured using high-performance liquid chromatography assay with tandem mass spectrometric detection, with lower limits of quantification of 25 and 10 pg/mL, respectively. Adrenal function was monitored by diurnal serum free and 24-hour urine cortisol concentrations. Despite the use of a sensitive assay and a high ciclesonide dose (800 microg/d), serum levels of ciclesonide and desisobutyryl-ciclesonide were below the lower limits of quantification for the majority of samples assayed. Ciclesonide was well tolerated and did not appear to affect serum or urine free cortisol levels. The low systemic exposure and favorable safety profile support the continued clinical development of ciclesonide nasal spray.

The normal uncinate process: histology and clinical relevance

In this three-center, prospective, non-randomized, controlled trial, we performed a qualitative and quantitative histological and morphometric assessment of the normal uncinate process (UP). The soft tissue and bony elements of the normal UP of 16 adults were investigated and compared with 28 age- and gender-matched archival reference-group samples of neighboring structures of the inferior and middle turbinates. A series of measurements were taken and included the thickness of the mucosal layers and bone, epithelial height, basement membrane thickness, number of lamina propria inflammatory cells, and the area fraction (AF) of the epithelium, connective tissue, glands, veins and arteries. The data showed that the medial and lateral mucosal layers are built of loose connective tissue and harbor various inflammatory cell population, abundant glands, and thin-walled small-caliber venules. In-between, there is a thin lamellar compact bone (≤ 80 μm) or a significantly thicker cancellous bone (110-400 μm; P < 0.001). Both mucosal layers are similar in thickness, epithelial height, basement membrane thickness, and AF of soft-tissue constituents. A comparison with the lateral aspect of the inferior and middle turbinates showed that the AF of the connective tissue, total submucosal glands, submucosal serous and mucous glands, and veins of the lateral mucosa are significantly different (all P < 0.001). This diversity may point to different physiological roles for the UP and the inferior and middle turbinates. The UP rich glandular network, which is probably responsible for drainage and ventilation of the maxillary sinus into the ethmoid infundibulum laterally and the frontal sinus into the middle meatus medially, supports the argument that it is preferable, particularly for the less complicated cases, to keep the normal physiology of the ethmoid infundibulum and use bone- and mucosa-sparing techniques for the management of refractory chronic sinus disease.

Roles of periostin in symptom manifestation and airway remodeling in a murine model of allergic rhinitis

PURPOSE

Periostin was originally identified as a secreted factor during screening of a mouse osteoblastic library. In a recent study, periostin was found to directly regulate eosinophil accumulation in allergic mucosal inflammation. Chronic eosinophilic inflammation is related to the development of remodeling. The present study examined the expression of periostin and evaluated its role in the inflammatory process and remodeling associated with allergic rhinitis.

METHODS

A murine model of allergic rhinitis was established in periostin knockout mice. We analyzed the expression of periostin, manifestation of nasal symptoms, eosinophilic inflammation, and subepithelial fibrosis as well as the expression of MMP-2, TIMP-1, and type 1 collagen in nasal tissue.

RESULTS

Periostin was mainly distributed in the subepithelial tissue of the nasal mucosa. The subepithelial tissue was thinner in the knockout group than in the control group. No differences in the expression of MMP-2 or TIMP-1 were found in the knockout group. However, after a month of allergen challenge, type I collagen in the nasal tissue was lower in the knockout group than in the control group. The number of eosinophils and the symptom score were also lower in the knockout group.

CONCLUSIONS

Periostin is expressed in nasal tissues of murine models of allergic rhinitis. Periostin deficiency may affect the remodeling of nasal tissue with reduced subepithelial fibrosis, and lead to less eosinophilic inflammation.

Tissue-type plasminogen activator depletion affects the nasal mucosa matrix reconstruction in allergic rhinitis mice

BACKGROUND

The present study was designed to assess the function of tissue plasminogen activator (t-PA) expression in allergic rhinitis.

METHODS

Age-matched t-PA gene knock out (t-PA(-/-)) and wild type (WT) mice were sensitised four times, and then challenged for six weeks with ovalbumin. The controls were treated with saline instead of ovalbumin. The structural change in the nasal mucosa was investigated with haematoxylin and eosin stain and van Gieson staining. u-PA (urokinase-type plasminogen activator) and PAI-1 (plasminogen activator inhibitor) gene expression were measured by real time PCR. Matrix metalloproteinase-9 (MMP-9) expression was tested with Western blotting and with real time PCR.

RESULTS

After ovalbumin challenge for six weeks, compared with the WT group, t-PA depletion increased collagen deposition and gland hyperplasia. u-PA and PAI-1 gene expression increased both in t-PA(-/-) and in WT mice after ovalbumin treatment. MMP-9 expression decreased greatly after ovalbumin challenge in t-PA(-/-) mice.

CONCLUSION

t-PA affects the nasal mucosa matrix reconstruction process in allergic rhinitis, with which MMP-9 is involved.

Nasal tactile sensitivity in allergic rhinitis

CONCLUSION

These preliminary data show a decrease in nasal tactile sensitivity and point out interesting aspects of the nasal chronic inflammatory condition in allergic rhinitis.

OBJECTIVES

The aim of this study was to evaluate the effects of allergic rhinitis on nasal tactile sensitivity during the intercritical period.

METHODS

A total of 70 patients aged between 18 and 67 years (average 42 years), with a positive history of allergy caused by seasonal outdoor allergens, were included (group A). Patient outcome was assessed by the nasal monofilament test: a set of 20 Semmes-Weinstein monofilaments was used to detect nasal sensitivity for both nasal cavities. The sensitivity threshold was recorded as the minimum monofilament size with which patients could detect at least two of three stimuli.

RESULTS

When compared to the control group (group B), subjects in group A required a significantly (p < 0.05) higher stimulus to trigger a touch response in the monofilament test, for both the inferior (195.1 ± 0.39 mg vs 67.7 ± 0.19 mg) and middle turbinate (108.7 ± 0.23 mg vs 67.7 ± 0.19 mg).

Remodelling of nasal mucosa in mild and severe persistent allergic rhinitis with special reference to the distribution of collagen, proteoglycans, and lymphatic vessels

BACKGROUND

Small leucine-rich repeat proteoglycans (decorin, biglycan, and lumican), collagen, and lymphangiogenesis are involved in tissue remodelling of various organs with inflammatory diseases.

OBJECTIVE

We determined the expression level and the distribution pattern of small leucine-rich repeat proteoglycans (decorin, biglycan, and lumican), collagen and lymphatic vessels in healthy, mild, and severe persistent allergic nasal mucosa.

METHODS

The distribution pattern of collagen, proteoglycans, and lymphatic vessels in healthy, mild, and severe persistent allergic nasal mucosa was evaluated by the van Gieson staining, immunohistochemistry, RT-PCR, and Western blotting. Quantitative analyses of collagen deposition were calculated as the median of the total percentage area in the tissue specimen. For the evaluation of proteoglycans, the percentage area stained and median optical density were measured for each image. Lymphatic vessels were identified by D2-40 antibody and calculated using the lymphatic vessel density and endothelial length density in tissue specimens. The expression of MMP 2 and 9, TIMP1 and 2 was evaluated with RT-PCR and Western blotting.

RESULTS

In mild and severe persistent allergic nasal mucosa, compared with healthy nasal mucosa, collagen showed more intense staining in the superficial and submucosal layer. In healthy and allergic nasal mucosa, decorin was lightly stained without significant differences in the percentage area and optical density of staining. However, lumican and biglycan showed strong immunoreactivity in mild and severe persistent allergic nasal mucosa, which was verified by Western blotting. The number and endothelial length density of lymphatic vessels were increased in mild and severe persistent allergic nasal mucosa compared with healthy nasal mucosa. The expression of MMP 9 was increased in severe persistent allergic rhinitis.

CONCLUSION AND CLINICAL RELEVANCE

These results suggest that the altered distribution pattern of collagen, proteoglycans, and lymphatic vessels could potentially modulate the remodelling of nasal mucosa in mild and severe persistent allergic nasal mucosa.

Remodeling of the lower and upper airways

Remodeling is defined as modeling again or differently, as reconstructing. Remodeling is a critical aspect of wound repair in all organs; it represents a dynamic process that associates the production and degradation of matrix in reaction to inflammation. This leads to normal reconstruction or a pathologic process. Aim and Methods: To compare data in the current literature on upper and lower airways. Results: Asthma is a chronic inflammatory disease associated with abnormal airways remodeling. In allergic rhinitis, another chronic inflammatory disease, remodeling is still poorly understood. Even though inflammation is similar in allergic rhinitis and asthma, the pathologic extent of nasal remodeling, as well as its clinical consequences, might be different from those in bronchi. Conclusion: Remodeling occurs less in upper airways compared to lower airways; it is apparent, however, that the structure of the rhinitic nose is not normal.

Nonasthmatic nasal polyposis patients with allergy exhibit greater epithelial MMP positivity

OBJECTIVE

To determine the influence of allergic rhinitis (AR) on the expression of matrix metalloproteinase (MMP)-9, MMP-2, and tissue inhibitor-1 of metalloproteinase (TIMP-1) in nasal polyposis.

STUDY DESIGN

A case-control study.

SETTING

A tertiary referral center.

SUBJECTS AND METHODS

The expression of MMP-9, MMP-2, and TIMP-1 was investigated in the nasal polyp tissue (NP) and maxillary sinus mucosa (MM) samples from 20 AR patients and 20 nonallergic patients undergoing endoscopic sinus surgery. Trichrome, periodic acid-Schiff, and hematoxylin-eosin staining were also performed and those expression levels were compared.

RESULTS

Infiltration of eosinophils was shown more intensely in NP rather than in MM, especially in the presence of AR. In the NP of AR patients, increased expression of MMP-9, MMP-2, and TIMP-1 was observed more prominently than in that of the control group. In case of MM, however, there was no significant difference between AR patients and the control group.

CONCLUSION

The presence of AR may enhance the expression of MMP-9, MMP-2, and TIMP-1 associated with airway remodeling in nasal polyposis.

Respiratory epithelial adenomatoid hamartoma of the anterior nasal septum a rare localisation of an unusual tumour in a child: a case report

INTRODUCTION

Hamartomas are non-neoplastic lesions constituted by a mixture of tissues indigenous to the region. Respiratory epithelial adenomatoid hamartomas are characterised by glandular proliferation lined by ciliated airway epithelium. Their localisation in the nasal cavity is rare and most frequent cases described so far were associated with the posterior nasal septum.

CASE PRESENTATION

A 9-year-old Caucasian boy presented with long-standing nasal obstruction. A large right nasal mass was evident on physical and CT examinations. It was surgically removed from the anterior nasal septum under general anaesthesia. Histologically, the diagnosis of REAH was established. The tumour lined by stratified squamous and ciliated respiratory epithelium was characterised by prominent glandular proliferation. By immunohistochemistry, the tumour was positive for cytokeratins, smooth muscle actin, vimentin, laminin, collagen type IV, CD8, and CD68. No S-100 immunoreactivity was observed. The patient has been asymptomatic for 12 months with completely healed lining of the nose.

CONCLUSION

Respiratory epithelial adenomatoid hamartoma, although rare, must be taken into consideration in differential diagnosis of nasal exophytic lesions.

Emedastine difumarate: a review of its potential ameliorating effect for tissue remodeling in allergic diseases

BACKGROUND

Emedastine difumarate, a selective histamine-H1 receptor antagonist and effective antiallergic agent, inhibits various clinical symptoms of allergic rhinitis, allergic conjunctivitis, urticaria, allergic dermatitis, pruritus cutaneous, and prurigo. In addition to greater efficacy than other antihistamines, emedastine difumarate produces no adverse cardiovascular effects and exhibits minimal anticholinergic activity. Moreover, a recent study revealed that the effect of emedastine difumarate on inhibition of histamine-induced collagen synthesis in vitro was greater in dermal fibroblasts than in nasal mucosa fibroblasts. This result indicates that there are tissue-specific effects of emedastine difumarate and that it may be more effective for treating fibrosis in skin than in nasal mucosa. However, the mechanism and role of tissue remodeling is less well established for allergic skin diseases and allergic conjunctivitis, in comparison to respiratory allergic diseases.

OBJECTIVE

This review outlines the involvement of histamine in the pathogenesis of tissue remodeling in a variety of organs, and presents the evidence for the effect of antihistamines on this process. Furthermore, this review also discusses antihistamines as an intervention strategy in tissue remodeling.

METHODS

The scientific literature, published abstracts, and selected textbooks were reviewed.

RESULTS/CONCLUSION

Although additional evidence is required, emerging evidence suggests that emedastine difumarate may be of value in the prevention of excess tissue remodeling in allergic skin inflammation.

Mucosal changes in chronic hypertrophic rhinitis after surgical turbinate reduction

Chronic nasal obstruction owed to chronic hypertrophic rhinitis is one of the most common problems encountered in rhinology. Various forms of conservative therapy have been used, but these are often ineffective and surgical reduction techniques have been successfully applied. However, the issue of postoperative histological changes in the nasal mucosa has not been adequately addressed. The aim of the present study was to comparatively evaluate the effect of the methods of submucosal monopolar diathermy, radiofrequency coblation and ultrasounds on the nasal mucosa. Sixty patients with chronic hypertrophic rhinitis of nonallergic etiology underwent different surgical methods of turbinate reduction, divided into two groups: (1) 30 patients underwent tissue volume reduction of the inferior nasal turbinates using ultrasound procedure on the left side and monopolar diathermy on the right; (2) 30 patients underwent radiofrequency coblation technique on the left side and ultrasound reduction on the right. We studied 20 preoperative specimens of the inferior turbinate mucosa taken randomly from both groups of patients, 5 from each side of each group. Normal nasal mucosal specimens taken from ten healthy persons were used as controls. Specimens of the inferior turbinate were taken after 1, 3, and 6 months after surgery, from the same patients. All specimens were examined by electron microscopy. Preoperative observation revealed degeneration of epithelial cells, loss of cilia, disruption of intercellular connections, edema, nasal mucus overproduction and inflammatory infiltration in chorium. Postoperative observations revealed decrease of intercellular edema, reduction of mucus, overproduction of collagen and degeneration of the epithelium to flattened stratified. Only specimens after use of ultrasounds showed islands with normally organized epithelium of columnar ciliated cells. It may be concluded that epithelial changes owed to chronic hypertrophic rhinitis do not significantly improve postoperatively after turbinate tissue volume reduction. Only in several cases operated with ultrasounds, regeneration of epithelium occurs, resulting to anatomical and functional restoration of the nasal physiology.

Relationship between rhinitis duration and worsening of nasal function

BACKGROUND

While it is well known that asthma is characterized by airway remodeling, few studies instead have investigated this issue in patients with allergic rhinitis (AR).

OBJECTIVE

The aim of the study was to evaluate nasal function, ie, nasal airflow, in a cohort of patients with persistent AR (PER).

METHODS

One hundred patients, 50 with short-term and 50 with long-term PER, were prospectively and consecutively evaluated, clinically evaluated by visit, skin prick test, and rhinomanometry.

RESULTS

Nasal airflow values were significantly lower (median flow: 348 mL/sec) in patients with long-term rhinitis (median duration nine years) as compared to patients with short-term (median duration one year) rhinitis (median flow: 466 mL/sec) (P < 0.0001).

CONCLUSION

This study provides the first evidence that patients with PER may show a progressive worsening of nasal airflow depending on the duration of the disorder.

Role of Fibrinolysis in the Nasal System

In this chapter, we show the presence of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), and plasminogen activator inhibitor-1 (PAI-1) in nasal mucosa. It is suggested that t-PA synthesized in mucous cells is promptly secreted and modifies the watery nasal discharge in allergic rhinitis and that u-PA activity may help with the passage of large amounts of rhinorrhea by reducing its viscosity. Furthermore, we clarify the relation between fibrinolytic components and the pathology of allergy, particularly during the development of nasal allergy and nasal tissue changes. Wild-type (WT) mice can develop nasal allergy for ovalbumin (OVA) sensitization, but PAI-1-deficient mice (PAI-1^-/-) cannot. The production of specific immunoglobulins IgG1 and IgE in the serum and production of interleukins IL-4 and IL-5 in splenocyte culture supernatant increased significantly in WT-OVA mice. In PAI-1^-/- mice, these reactions were absent, and specific IgG2a in serum and interferon-γ in splenocyte culture medium increased significantly. Histopathologically, there was marked goblet cell hyperplasia and eosinophil infiltration into the nasal mucosa in WT-OVA mice, but these were absent in PAI-1^-/- mice. These results indicate that the immune response in WT-OVA mice can be classified as a dominant Th2 response, which would promote collagen deposition. In contrast, the Th2 response in PAI-1^-/- mice was down-regulated and the immune response shifted from Th2-dominant reaction to a Th1-dominant one. Taken together, these findings suggest that PAI-1 plays an important role not only in thrombolysis but also in the immune response.

Prolonged allergen challenge in murine nasal allergic rhinitis: nasal airway remodeling and adaptation of nasal airway responsiveness

BACKGROUND

Nasal airway remodeling exists in allergic rhinitis, but it appears to be far less extensive than in asthma. However, there has been little study about nasal airway remodeling and no study using mice models. It has been reported that airway hyperresponsiveness decreased after prolonged allergen challenge in a chronic murine asthma model together with the progression of remodeling. However, there has been no study of the relation of remodeling and airway responsiveness in nasal allergy. Therefore, we have undertaken this investigation to characterize nasal airway structural changes after prolonged allergen challenge and to examine the relationship between nasal airway hyperresponsivity and remodeling.

METHODS

We prepared murine allergic rhinitis for ovalbumin. Mice were subsequently challenged three times a week with ovalbumin from day 19 to days 53, 88, and 130. We examined allergen-induced nasal symptoms and objective nasal hyperresponsiveness using the enhanced pause system. Moreover, the pathologic changes were investigated after allergen challenge.

RESULTS

The extended allergen challenge protocol caused significant nasal airway remodeling. Specifically, remodeling was characterized by goblet cell hyperplasia and deposition of collagen in the submucosal area. Allergen-induced nasal hyperresponsiveness was first increased but gradually decreased in nasal symptoms and Penh after prolonged allergen challenge.

CONCLUSIONS

We have demonstrated that a remodeling of nasal mucosa in a murine allergic rhinitis model prolonged allergen exposure. Moreover, prolonged allergen exposure induced a reduction of nasal hyperresponsiveness together with a progression of nasal remodeling.

Cytokeratin expression in palatal and marginal mucosa of cleft palate patients

OBJECTIVE

The margin of a palatal cleft is a unique anatomical site since the palatal mucosa is continuous with the nasal or nasopharyngeal mucosa. The aim of this study was to compare the expression patterns of cytokeratins and basal membrane components of the mucosa in the area of the cleft.

DESIGN

Biopsies from the mucosa of the hard palate and from the cleft margin in the soft palate were obtained from five patients during the primary surgical closure of the cleft. The tissues were processed for haematoxylin-eosin staining and for immunohistochemistry. Antibodies against the cytokeratins (CK) 4, 7, 8, 10, 13, 16 and 18, and the basal membrane components heparan sulphate (HS) and collagen type IV (CIV) were used for immunostaining.

RESULTS

The nasopharyngeal epithelium was thinner than the epithelium of the soft palatal mucosa, and showed less interpapillary ridges. The nasopharyngeal epithelium was stratified but expressed the keratins of a simple epithelium (CK 7, 8 and 18). The expression pattern abruptly changed into that of a typical non-keratinized stratified epithelium (CK 4, 13) at the transition to the soft palatal epithelium. The epithelium of the hard palate was a fully differentiated, keratinized and stratified epithelium (CK 10, 16). The basal membrane was thinner in the nasopharyngeal epithelium, which might be related to the presence of abundant inflammatory cells.

CONCLUSION

The area around the palatal cleft showed three different types of epithelium. There was an abrupt transition in phenotype of the epithelium from the oral side to the nasopharyngeal side.

Induction of airway remodeling of nasal mucosa by repetitive allergen challenge in a murine model of allergic rhinitis

BACKGROUND

Although many studies regarding airway remodeling in asthma have been reported, only a few studies have investigated airway remodeling in allergic rhinitis.

OBJECTIVES

To determine whether repetitive allergen challenge could induce airway remodeling in the nose and evaluate the effect of steroids using a murine model of allergic rhinitis.

METHODS

To develop a mouse model of airway remodeling, ovalbumin-sensitized mice were repeatedly exposed to inhaled ovalbumin administration twice a week for 1 month and 3 months. Matched control mice were challenged with phosphate-buffered saline, and the treatment group received intraperitoneal dexamethasone injection. Trichrome, periodic acid-Schiff, hematoxylin-eosin, and immunohistochemical staining against matrix metalloproteinase 9 and tissue inhibitors of metalloproteinase 1 were performed to nasal and lung tissues, and the level of transforming growth factor beta in the nasal lavage fluid was analyzed.

RESULTS

Repetitive ovalbumin challenge for 3 months induced circumferential peribronchial fibrosis in the lung. In the nose, subepithelial fibrosis, increased matrix metalloproteinase 9 and tissue inhibitors of metalloproteinase 1 expression, goblet cell hyperplasia, and submucous gland hypertrophy were observed compared with the control group. Features of airway remodeling were more prominent in the lung tissue. Administration of dexamethasone significantly inhibited these histologic changes.

CONCLUSION

Airway remodeling associated with long-term allergen challenge can occur in the nasal mucosa and the lung. Steroid treatment prevents airway inflammation in response to acute allergen challenge, as well as airway remodeling by long-term allergen challenge.

Tissue remodelling in upper airways: where is the link with lower airway remodelling?

Tissue remodelling reported in upper airways include epithelial hyperplasia, increased matrix deposition in the nasal or paranasal lining, matrix degradation and accumulation of plasma proteins. Genetic influences, foetal exposures and early life events may contribute to structural changes such as subepithelial fibrosis from an early age. Other structural alterations are related to duration of the disease and long-term uncontrolled inflammation. Structural changes may increase alteration of the protective functions of the upper airways namely by affecting mucociliary clearance and conditioning of inspired air. The sequences of tissue changes during wound repair of upper airway mucosa after surgery are illustrative of the complexicity of tissue modelling and remodelling and could be considered as an important source of information for a better understanding of the complex relationship between inflammatory reaction, of the subsequent tissue damages and fibroblast metabolism of upper airways.

Upregulation of oncostatin m in allergic rhinitis

OBJECTIVES

Oncostatin M is a multifunctional cytokine belonging to the interleukin-6 family of cytokines. It has been implicated as an important modulator of lower airway remodeling in the setting of asthma. However, there have been few studies regarding a similar role for the upper airway epithelium in the setting of allergic rhinitis. This study was undertaken to investigate the expression of oncostatin M mRNA and protein in normal and allergic rhinitis nasal mucosa and to localize the expression of the oncostatin M protein in allergic rhinitis.

MATERIALS AND METHODS

Inferior turbinate mucosa samples from 20 patients with perennial allergic rhinitis and 20 matched normal control subjects were obtained. Oncostatin M mRNA was extracted from the inferior turbinate mucosae, then reverse transcriptase-polymerase chain reaction was performed and analyzed semiquantitatively. Differences in expression levels of oncostatin M protein between samples from allergic rhinitis patients and normal control subjects were analyzed through Western blot, and oncostatin M protein was localized immunohistochemically.

RESULTS

The expression levels of oncostatin M mRNA and protein were significantly upregulated in patients with allergic rhinitis mucosa. Oncostatin M protein was predominantly localized in the surface epithelium, infiltrating inflammatory cells, vascular endothelium, and submucosal glands and was more strongly expressed in the nasal mucosa of patients with allergic rhinitis than in normal control subjects.

CONCLUSIONS

Oncostatin M is expressed in the human nasal mucosa and is upregulated in the setting of allergic nasal inflammation. These results suggest a possible contribution of oncostatin M in the remodeling of the nasal mucosa in allergic rhinitis.

Protection of plasminogen activator inhibitor-1-deficient mice from nasal allergy

This study was performed to clarify the relationship between fibrinolytic components and the pathology of allergy, particularly that during the development of nasal allergy and nasal tissue changes. Intranasal OVA challenge after sensitization by i.p. administration of OVA induced a higher level of excess subepithelial collagen deposition in wild-type (WT) C57BL/6J mice than in plasminogen activator inhibitor (PAI)-1-deficient (PAI-1(-/-)) mice. The excess PAI-1 induction in the nasal mucosa and higher level of active PAI-1 in the nasal lavage fluid of WT-OVA mice compared with those in WT-control mice suggested that the decrease of proteolytic activity inhibits the removal of subepithelial collagen. The frequency of sneezing, nasal rubbing, nasal hyperresponsiveness, production of specific IgG1 and IgE in the serum, and production of IL-4 and IL-5 in splenocyte culture supernatant increased significantly in WT-OVA mice. In PAI-1(-/-) mice, these reactions were absent, and specific IgG2a in serum and IFN-gamma in splenocyte culture medium increased significantly. Histopathologically, there were marked goblet cell hyperplasia and eosinophil infiltration into the nasal mucosa in WT-OVA mice, but these were absent in PAI-1(-/-) mice. These results indicate that the immune response in WT-OVA mice can be classified as a dominant Th2 response, which would promote collagen deposition. In contrast, the Th2 response in PAI-1(-/-) mice was down-regulated, and the immune response shifted from Th2-dominant reaction to a Th1-dominant one. Taken together, these findings suggest that PAI-1 plays an important role not only in thrombolysis but also in immune response.

Remodelling of the upper airways in allergic rhinitis: is it a feature of the disease?

The traditional viewpoint that inflammation, owing to a genetic T-helper type 2 (Th2)-directed imbalance, is the cause of allergic rhinitis has meant that the potential coexistence of other genetic defects and the relevance of any airway remodelling changes to disease pathogenesis and persistence have received scant attention, and as such remain controversial areas. This is particularly so in view of the limited published work in this field, which has so far reported markedly conflicting findings. This review endeavours to outline what is known about the nature of the remodelling response within the upper airway in allergic rhinitis, in addition to highlighting specific areas where further research is warranted.

Neuronal nitric oxide synthase immunoreactivity in the nasal mucosa of patients with idiopathic and allergic rhinitis

The localization of neuronal nitric oxide synthase (nNOS) in the mucosa of the inferior and middle turbinates of 30 patients with and without allergic rhinitis was examined by immunohistochemical methods. Staining of paraffin sections from allergic and nonallergic patients revealed nNOS immunoreactivity (nNOS-IR) in the muscular layer of vessels, in the basal portion of submucosal glands and in the periost and the osteocytes of the turbinate bones. In contrast to earlier investigations, nNOS-IR was also seen in the nasal respiratory epithelium of allergic and nonallergic patients. The immunostaining of sections of submucosal glands from allergic patients was stronger than that of sections from patients with idiopathic rhinitis or patients with no nasal obstruction. The present result - nNOS-IR around glands is elevated in patients with allergic rhinitis - could indicate that this enzyme is involved in the pathogenesis and symptomatology of allergic rhinitis.

Expression of platelet-derived endothelial cell growth factor and vascularity in the nasal mucosa from allergic rhinitis

BACKGROUND

Angiogenesis plays critical roles in various pathological mechanisms. It has been hypothesized that the vascularity in allergic nasal mucosa is different from that in normal mucosa, and that changes in the vascular network contributes the pathogenesis of allergic rhinitis.

OBJECTIVE

To determine whether hypervascularity and overexpression of the platelet-derived endothelial cell growth factor (PD-ECGF), an angiogenic factor, are found in allergic nasal mucosa and whether these two factors are associated with the allergic reaction.

METHODS

We investigated the expression of PD-ECGF and counted microvessels in 51 nasal mucosae (30 samples from patients with allergic rhinitis and 21 samples as control from normal subjects) using an immunohistochemical technique.

RESULTS

PD-ECGF expression in allergic nasal mucosae was significantly higher than that in control mucosae at the interstitium of the lamina propria (P = 0.0024) and nasal gland (P = 0.024). PD-ECGF positive areas were coincident with areas of high vascularity in the sections. The microvessel count in the lamina propria of allergic mucosae was higher than that of control mucosae (P = 0.050). Regarding the correlation with various clinical factors, the total nasal symptom score was significantly associated with both the PD-ECGF expression in the interstitium of the lamina propria (P < 0.05) and in the nasal gland (P < 0.005), as well as with the number of vessels (P < 0.05).

CONCLUSION

PD-ECGF and hypervascularity in the nasal mucosa may be involved in the pathogenesis of allergic rhinitis.

Molecular pathology of allergic disease. II: Upper airway disease

Allergic upper airway diseases such as allergic rhinitis and chronic sinusitis are an increasing problem. Although the pathogenesis remains elusive, an individual's genetic predisposition as well as exposure to the allergen are currently considered factors in their development. Clinical symptoms of sneezing, rhinorrhea, and congestion are primarily a consequence of granulocyte release of chemical mediators such as histamine, prostanoids, and leukotrienes as well as the infiltration of inflammatory cells. Observations subsequent to allergen provocation are comparable to natural exposure and as such much of our understanding of allergic responses is derived from this model. A prominence of CD4(+) T cells and eosinophils, synthesis and release of T(H)2 cytokines, and the coordinate expression of chemokines and adhesion molecules are all characteristic of the allergic response observed in rhinitis and sinusitis. Corticosteroids and immunotherapy target these inflammatory processes and have been observed to successfully reduce and shift the predominantly T(H)2 environment toward T(H)1 cytokine expression. As our understanding of the pathophysiologic features of allergic upper airway disease improves, as well as the relationship between their development and that of lower airway disease, new strategies of diagnosis and treatment will allow for more effective modulation of the allergic process and associated morbidity.