Distinct expression of SARS-CoV-2 receptor ACE2 correlates with endotypes of chronic rhinosinusitis with nasal polyps.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry factors, ACE2 and TMPRSS2, are highly expressed in nasal epithelial cells. However, the association between SARS-CoV-2 and nasal inflammation in chronic rhinosinusitis with nasal polyps (CRSwNP) has not been investigated. We thus investigated the expression of SARS-CoV-2 entry factors in nasal tissues of CRSwNP patients, and their associations with inflammatory endotypes of CRSwNP. METHODS: The expression of ACE2 and TMPRSS2 was assessed in nasal tissues of control subjects and eosinophilic CRSwNP (ECRSwNP) and nonECRSwNP patients. The correlations between ACE2/TMPRSS2 expression and inflammatory indices of CRSwNP endotypes were evaluated. Regulation of ACE2/TMPRSS2 expression by inflammatory cytokines and glucocorticoids was investigated. RESULTS: ACE2 expression was significantly increased in nasal tissues of nonECRSwNP patients compared to ECRSwNP patients and control subjects, and positively correlated with the expression of IFN-γ, but negatively correlated with tissue infiltrated eosinophils, and expression of IL5 and IL13. IFN-γ up-regulated ACE2 expression while glucocorticoid attenuated this increase in cultured nasal epithelial cells. Genes co-expressed with ACE2 were enriched in pathways relating to defence response to virus in nasal tissue. TMPRSS2 expression was decreased in nasal tissues of CRSwNP patients compared to control subjects and not correlated with the inflammatory endotypes of CRSwNP. Glucocorticoid treatment decreased ACE2 expression in nasal tissues of nonECRSwNP patients, but not in ECRSwNP patients, whereas TMPRSS2 expression was not affected. CONCLUSION: These findings indicate that ACE2 expression, regulated by IFN-γ, is increased in nasal tissues of nonECRSwNP patients and positively correlates with type 1 inflammation.

Reduction in superoxide dismutase expression in the epithelial mucosa of eosinophilic chronic rhinosinusitis with nasal polyps.

BACKGROUND: Eosinophils generate large amounts of oxidant species. The eosinophil-dominant type of chronic rhinosinusitis (CRS) with nasal polyps is related to more extensive disease and a decreased likelihood of surgical success. Superoxide dismutase (SOD) is the first-line and only antioxidant enzyme that converts superoxide to hydrogen peroxide. METHODS: The patients with CRS with nasal polyps were divided into eosinophilic and noneosinophilic groups. The expression of three isoforms of SOD, intracellular copper-zinc SOD (CuZnSOD), mitochondrial manganese SOD (MnSOD) and extracellular SOD (ECSOD), were examined by enzyme activity assay, immunohistochemistry and quantitative real-time RT-PCR sampled by laser capture microdissection. RESULTS: SOD activity in the eosinophilic and noneosinophilic groups was significantly reduced compared to that of the control groups. Immunostaining of both CuZnSOD and MnSOD in the eosinophilic group was significantly decreased compared with that in the noneosinophilic and control groups. CuZnSOD mRNA of the eosinophilic group was significantly decreased compared with that of the control group, whereas MnSOD mRNA in the eosinophilic group was significantly decreased compared with that in the noneosinophilic and control groups. Neither immunoreactivity nor mRNA of ECSOD was different among the three groups. The degree of epithelial damage and disease severity were inversely correlated with CuZnSOD and MnSOD immunoreactivity. CONCLUSIONS: The reduction in SOD activity and the downregulation of the SOD message are suggested to be related to eosinophil recruitment and epithelial damage of CRS with nasal polyps.

Glycogen synthase kinase 3 in chronic rhinosinusitis: two faces of a single enzyme in one disease.

BACKGROUND: The origin and pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) remain unclear. Glycogen synthase kinase 3 (GSK-3) is a unique multitasking kinase involved in the regulation of inflammation and apoptosis and is an important messenger in the downstream signaling of interleukin 6. OBJECTIVE: To analyze the possible role of GSK-3 in the pathogenesis of CRSwNP. METHODS: We examined tissue samples of nasal polyps and the inferior turbinate of patients with CRSwNP and the inferior turbinate of individuals without chronic sinusitis (healthy mucosa). Expression levels of GSK-3 and its inactivated form phosphorylated GSK-3 (pGSK-3) were analyzed using DNA microarray, protein array, Western hybridization, and immunohistochemical analysis. RESULTS: We found increased expression of GSK-3 in both the nasal polyps and the inferior turbinate of patients with CRSwNP compared with those with healthy mucosa (P < .01). We did not observe a difference between nasal polyps and the inferior turbinate of patients with CRSwNP, but a highly significant increase in the phosphorylation rate of GSK-3 was detected in the tissue of nasal polyps compared with the turbinates of patients with CRSwNP (P < .01). CONCLUSION: GSK-3 may play a crucial role in the inflammatory process in CRSwNP. Nasal polyps originate mainly in the mucosa of the middle meatus of the nose and rarely occur in the region of the inferior turbinate. The inhibition of GSK-3 by phosphorylation in nasal polyps, in contrast to the inferior turbinate, is a possible explanation for the different behavior of the mucosa of the middle meatus and the inferior turbinate.

[Role of the -765 G/C polymorphism of COX-2 gene in pathogenesis of chronic rhinosinusitis with nose polyps in a Polish population]. / Znaczenie polimorfizmu -765G/C genu COX-2 dla patogenezy przewleklego zapalenia zatok przynosowych z polipami nosa w populacji polskiej.

INTRODUCTION: It is believed that local factors within the nasal cavities contribute to the formation of nasal polyps. The disruption of local homeostasis mechanisms in a chronic inflammatory process is one of those factors. Cyclooxygenase (COX)-2 expression is activated in the course of the immune response to extracellular and intracellular stimuli. Also, an increase of the gene expression can be associated with the development of nasal polyps in patients with chronic sinusitis. THE AIM OF THE STUDY: The aim of this study was an evaluation of the role of the -765G/C COX-2 polymorphism in sinusitis pathogenesis in patients with nasal polyps. MATERIALS AND METHODS: The study group consisted of 100 patients, aged 35-65, with chronic sinusitis and nasal polyps and 150 people in the age, sex-, age- and ethnicity-matched control group. The study material included DNA isolated from peripheral blood lymphocytes of the patients and the controls. PCR-RFLP method was used in genotyping polymorphic variants of COX-2. RESULTS: In comparison to the control group, the group of the patients with chronic sinusitis and nasal polyps showed a statistically significant increase in the occurrence frequency of the -765G/C polymorphic variant of COX-2 gene (OR 4.04; 95% CI 2.32-7.03; p > 0.001) and C allele (OR 3.68; 95% CI 2.38-5.68; p < 0.001). CONCLUSIONS: The -765G/C genotype of COX-2 can be associated with an increased risk of the occurrence of chronic sinusitis with nasal polyps in the Polish population.

Differential expression of angiotensin-converting enzyme-2 in human paranasal sinus mucosa in patients with chronic rhinosinusitis.

OBJECTIVE: Severe acute respiratory syndrome coronavirus-2 uses angiotensin-converting enzyme-2 as a primary receptor for invasion. This study investigated angiotensin-converting enzyme-2 expression in the sinonasal mucosa of patients with chronic rhinosinusitis, as this could be linked to a susceptibility to severe acute respiratory syndrome coronavirus-2 infection. METHODS: Ethmoid sinus specimens were obtained from 27 patients with eosinophilic chronic rhinosinusitis, 18 with non-eosinophilic chronic rhinosinusitis and 18 controls. The angiotensin-converting enzyme-2 and other inflammatory cytokine and chemokine messenger RNA levels were assessed by quantitative reverse transcription polymerase chain reaction. Angiotensin-converting enzyme-2 positive cells were examined immunohistologically. RESULTS: The eosinophilic chronic rhinosinusitis patients showed a significant decrease in angiotensin-converting enzyme-2 messenger RNA expression. In the chronic rhinosinusitis patients, angiotensin-converting enzyme-2 messenger RNA levels were positively correlated with tumour necrosis factor-α and interleukin-1ß (r = 0.4971 and r = 0.3082, respectively), and negatively correlated with eotaxin-3 (r = -0.2938). Angiotensin-converting enzyme-2 immunoreactivity was mainly localised in the ciliated epithelial cells. CONCLUSION: Eosinophilic chronic rhinosinusitis patients with type 2 inflammation showed decreased angiotensin-converting enzyme-2 expression in their sinus mucosa. Angiotensin-converting enzyme-2 regulation was positively related to pro-inflammatory cytokines, especially tumour necrosis factor-α production, in chronic rhinosinusitis patients.

[Cathepsin D activity in chronic rhinosinusitis with nasal polyps]. / Ocena aktywnosci katepsyny D w blonie sluzowej pacjentów z przewleklym zapaleniem zatok przynosowych z polipami.

UNLABELLED: Nasal polyposis affects about 1 to 4% of the population. Polyps develop in oedematous and inflammated mucous membrane. In spite of the intensive research the pathomechanism of their development is not fully understood. The majority of the theories concerning the development of nasal polyps emphasize the role of the inflammatory process causing the rupture of the epithelium and the basal membrane. Cathepsin D is one of important mediators of inflammatory processes, that may be involved in the pathogenesis of nasal polyposis. THE AIM OF THE STUDY: was to establish the role of the cathepsin D in the pathogenesis of nasal polyps. MATHERIAL AND METHOD: Tissues were taken from 39 patients treated with endoscopic sinus surgery due to chronic rhinosinusitis with polyps. The activity of the cathepsin D was assesed with spectrofotometric method using the specific inhibitor (pepstatin) in tissue of nasal polyps, in oedematous and the inflammated mucous membrane of the nasal conchae and the samples of mucous membrane taken from the nasal septum. RESULTS: Statistically significant difference in cathepsin D activity between polypoid tissue, inflammated mucosa and the mucous membrane of the nasal septum was detected (t-student test, p < 0.05). No difference in the activity of this enzyme was observed between the polypoid tissue and the inflammated mucosa. CONCLUSION: Increased activity of the cathepsin D in nasal polyps and inflammatory changed mucosa confirm the important role of the cathepsin D in inflammatory processes leading to damage and subsequent remodeling of mucous membrane. We believe that further research on the activity of other proteolytic enzymes is necessary to demonstrate the differences between the inflammable changed mucous membrane and nasal polyps.

[The role of infection in the development of polypous rhinosinusitis in patients with bronchial asthma].

At present, many authors accept the many-factor theory of development of polypous rhinosinusitis associated with bronchial asthma according to which this condition should be regarded as an inflammatory syndrome in subjects predisposed to a specific tissue reaction. Inflammation induced by an infection is accompanied by the release of protease-inhibiting enzymes that turn inflammation into a chronic process thereby contributing to tissue disintegration, remodeling of mucous membranes, and development of polyps.

[Study on the relationship between 11ß-hydroxysteroid dehydrogenase and glucocorticoid response in nasal polyps].

Objective: To investigate the expression of 11ß-hydroxysteroid dehydrogenase (11ß-HSD) in polyps of patients with chronic rhinosinusitis with nasal polyps (CRSwNP) and its correlation with glucocorticoid sensitivity. Methods: The prospective study method was applied. Forty-three adult CRSwNP patients from Otorhinolaryngology Hospital, First Affiliated Hospital of Sun Yat-sen University between April 2016 and June 2017 were enrolled in this study. There were 19 males and 24 females with the age of (37.44±7.42) years old. The endoscopic scores by nasal Polyps Grading System before and after one-week prednisone treatment (0.5 mg/(kg·d)) were evaluated. The response of glucocorticoid by the total endoscopic scores was estimated. According to the patient's reduced nasal polyp endoscopic score, patients were devided into nasal polyps insensitive to glucocorticoids treatment group (insensitive group) and nasal polyp sensitive to glucocorticoids treatment group (sensitive group). The expression of 11ß-HSD1, 11ß-HSD2 in nasal polyps were measured by Real-time PCR (RT-PCR), Western Blot and immunohistochemisty. According to the clinical data, the Logistic regression models and receiver operation characteristics (ROC) curves were used to explore the predictor for glucocorticoid response in CRSwNP. Results: The expression of 11ß-HSD1 and 11ß-HSD1/11ß-HSD2 was higher in sensitive group than that of insensitive group, while the expression of 11ß-HSD2 was lower (rank average was 26.08 vs 16.33, 27.24 vs 14.72, 18.66 vs 26.64, Z value was -2.511, 0.323, -2.059, respectively, all P<0.05). The endoscopic scores in CRSwNP group declined whereas the expression of 11ß-HSD1/11ß-HSD2 increased (r=0.528, P=0.001), while the cutoff value of the ratio of 11ß-HSD1/11ß-HSD2 was 2.290 (sensitivity was 79.17%, specificity was 88.89%). Conclusions: There is a positive correlation between the response of glucocorticoid and the ratio of 11ß-HSD1/11ß-HSD2, which could be used as a marker in predicting the level of tissue response to glucocorticoid therapy in CRSwNP.

Increased nasal matrix metalloproteinase-1 and -9 expression in smokers with chronic rhinosinusitis and asthma.

A potential mechanism underlying cigarette smoke-induced airway disease is insufficient tissue repair via altered production of matrix metalloproteinases (MMPs). Osteitis is a signature feature of recalcitrant chronic rhinosinusitis (CRS) and often results in revision surgery. The present study aimed to investigate MMP expression in the nasal tissues of asthmatic patients with CRS and any association with cigarette smoking and osteitis. Thirteen smokers with CRS and asthma, 16 non-smokers with CRS and asthma, and seven non-smoker asthmatic patients without CRS were prospectively recruited. The expression of MMPs and associated immunological factors in surgically-obtained nasal tissues was evaluated via real-time PCR and western blotting. Maximal bone thickness of the anterior ethmoid (AE) partition was measured in axial sinus computed tomography (CT) sections. MMP-1 and MMP-9 expression was increased in the nasal tissues of smokers with asthma and CRS via real-time PCR and western blot. Maximal AE partition bone thickness was greater in smokers with CRS and asthma than in non-smokers with CRS and asthma. MMP-1 and MMP-9 levels were correlated with maximal AE bone thickness. Cigarette smoking was associated with the up-regulation of MMP-1 and MMP-9 in the nasal tissues of patients with airway inflammatory diseases, and with AE osteitis, and with therapeutic resistence.

Oxidative CaMKII as a potential target for inflammatory disease (Review).

CaMKII is a calcium­activated kinase, proved to be modulated by oxidation. Currently, the oxidative activation of CaMKII exists in several models of asthma, chronic rhinosinusitis with nasal polyps, cardiovascular disease, diabetes mellitus, acute ischemic stroke and cancer. Oxidized CaMKII (ox­CaMKII) may be important in several of these diseases. The present review examines the mechanism underlying the oxidative activation of CaMKII and summarizes the current findings associated with the function of ox­CaMKII in inflammatory diseases. Taken together, the findings of this review aim to improve current understanding of the function of ox­CaMKII and provide novel insights for future research.

Role of matrix metalloproteinases in chronic rhinosinusitis.

PURPOSE OF REVIEW: In this review, we discuss the role of matrix metalloproteinases and the potential therapeutic inhibition of metalloproteinases in chronic rhinosinusitis. Metalloproteinases control tissue remodelling along with several other physiologic processes. Failures may cause extracellular matrix deposition and sustained inflammation, which are common features in chronic rhinosinusitis. RECENT FINDINGS: Metalloproteinases are rarely studied in chronic rhinosinusitis. Upregulation of certain metalloproteinases (gelatinases, collagenases and matrilysin) is described in the literature. The results are partly controversial, suggesting that metalloproteinases are implicated in the destructive processes in the disease pathogenesis, but also demonstrate that they may exert an anti-inflammatory function in chronic rhinosinusitis. The imbalance between metalloproteinases and the tissue inhibitor of metalloproteinases is proposed to be crucial in the extracellular matrix deposition in asthma, and it may also lead to pathologic tissue remodelling in chronic rhinosinusitis. SUMMARY: Metalloproteinases are implicated in the chronic respiratory-tract diseases, but little is known about their detailed functions in disease pathogenesis. Metalloproteinases may serve as tools in evaluating prognosis and provide a target for novel therapies, highlighting the need for better understanding of metalloproteinase functions in chronic rhinosinusitis.

The expression of MMP-2, MMP-7, MMP-9, and TIMP-1 in chronic rhinosinusitis and nasal polyposis.

OBJECTIVES: To investigate the expression and clinical significance of MMP-2, MMP-7, MMP-9, and TIMP-1 in patients with nasal polyposis (NP) and chronic rhinosinusitis (CRS). STUDY DESIGN: Prospective study. SUBJECTS AND METHODS: This study involved 54 patients. There were three groups: nasal polyposis group, chronic rhinosinusitis group, and control group. Specimens were collected during endoscopic sinus surgery. Each sample was immunohistochemically examined. RESULTS: Expression of MMP-2 was found significantly increased in NP, whereas MMP-7 expression was found significantly increased in CRS (P < 0.001). TIMP-1 was significantly high in control group compared to CRS and NP (P < 0.001 and P = 0.002, respectively). CONCLUSIONS: Different regulation type of activation of MMPs has been found in these two diseases. If MMP-2 expression is intense in the mucosa, then this ends with polyp formation; if MMP-7 expression is intense, it ends with CRS or stays as CRS.

Hydrocephalus, situs inversus, chronic sinusitis, and male infertility in DNA polymerase lambda-deficient mice: possible implication for the pathogenesis of immotile cilia syndrome.

A growing number of DNA polymerases have been identified, although their physiological function and relation to human disease remain mostly unknown. DNA polymerase lambda (Pol lambda; also known as Pol beta2) has recently been identified as a member of the X family of DNA polymerases and shares 32% amino acid sequence identity with DNA Pol beta within the polymerase domain. With the use of homologous recombination, we generated Pol lambda(-/-) mice. Pol lambda(-/-) mice develop hydrocephalus with marked dilation of the lateral ventricles and exhibit a high rate of mortality after birth, although embryonic development appears normal. Pol lambda(-/-) mice also show situs inversus totalis and chronic suppurative sinusitis. The surviving male, but not female, Pol lambda(-/-) mice are sterile as a result of spermatozoal immobility. Microinjection of sperm from male Pol lambda(-/-) mice into oocytes gives rise to normal offspring, suggesting that the meiotic process is not impaired. Ultrastructural analysis reveals that inner dynein arms of cilia from both the ependymal cell layer and respiratory epithelium are defective, which may underlie the pathogenesis of hydrocephalus, situs inversus totalis, chronic sinusitis, and male infertility. Sensitivity of Pol lambda(-/-) cells to various kinds of DNA damage is indistinguishable from that of Pol lambda(+/+) cells. Collectively, Pol lambda(-/-) mice may provide a useful model for clarifying the pathogenesis of immotile cilia syndrome.

Metalloproteinase function in chronic rhinosinusitis with nasal polyposis.

OBJECTIVES: Chronic rhinosinusitis with nasal polyposis (CRSwNP) and asthma share characteristic inflammatory features and histopathologic findings of airway remodeling. Remodeling, which is controlled by matrix metalloproteinases (MMP), is a key event in the pathogenesis of asthma. The MMP functions have rarely been evaluated in CRSwNP. STUDY DESIGN: Prospective and in vivo. METHODS: MMP-7, MMP-8, MMP-9, and tissue inhibitor of metalloproteinase (TIMP)-1 concentrations were analyzed by enzyme-linked immunosorbent assay and their molecular forms by Western immunoblotting and gelatin zymography in 24 patients operated on for CRSwNP and in nasal lavages from 19 healthy controls. MMP function, protective or destructive, was evaluated by comparing MMP/TIMP-1 levels with the disease activity, estimated by tissue eosinophilia and a need for re-operations. RESULTS: Significantly increased levels of MMP-8/TIMP-1 and MMP-9/TIMP-1 were found in patients without tissue eosinophilia relative to eosinophil-positive CRSwNP patients and controls, as well as in patients who did not require re-operation in comparison with re-operated patients. In eosinophil-positive and re-operated patients, these parameters were within the same range than in controls. CONCLUSIONS: Proteolytic spectrum is different in eosinophilic and noneosinophilic CRSwNP, suggesting a new mechanism for eosinophil accumulation in the disease pathogenesis. Enhanced MMP-8 and MMP-9 expression was associated with a better prognosis/clinical outcome, and thus these results may represent a synergic, protective role of MMP-8 and MMP-9 in host response in CRSwNP. Because synthetic MMP inhibitors, capable of equilibrating the unfavorable MMP/TIMP-ratio, may be of potential therapeutic value in chronic respiratory tract diseases, the MMP functions in inflammatory conditions need to be carefully established.

Emerging Role of Proteases in the Pathogenesis of Chronic Rhinosinusitis with Nasal Polyps.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous upper airway disease with multiple etiologies. Clinically, CRSwNP can be classified into either eosinophilic or non-eosinophilic subtypes. The eosinophilic phenotype of CRSwNP is widely thought to be highly associated with recurrence of nasal polyps or surgical failure. Epithelial cells have a crucial role in the development of Th2-biased airway diseases. Recent studies have shown that a wide range of external stimuli such as allergens and microorganisms can elicit the release of epithelial-derived Th2-driving cytokines and chemokines. Protease activity is a feature common to these multiple environmental insults and there is growing evidence for the concept that an imbalance of proteases and protease inhibitors in the epithelial barrier leads to both the initiation and maintenance of chronic eosinophilic airway inflammation. In this review, we analyze recent work on the role of proteases in the development of the sinonasal mucosal type 2 immune response with an emphasis on the molecular pathways promoting adaptive Th2 cell immunity.

Local and systemic proteolytic responses in chronic rhinosinusitis with nasal polyposis and asthma.

BACKGROUND: Chronic rhinosinusitis with nasal polyposis (CRSwNP) and asthma coexist frequently and share similar features of inflammation and remodeling. Remodeling has become an important concept in the pathophysiology of asthma and CRSwNP. It happens early in the development of these diseases and is relatively resistant to treatments. The key enzymes responsible for remodeling are matrix metalloproteinases (MMPs). In this study we examined whether asthma and CRSwNP share similar MMP profiles. METHODS: Nasal secretion and serum specimens of controls (19 subjects) and patients with asthma (12), CRSwNP (39), or both (16) were collected between December 2007 and May 2009. Groups were divided into 2 subgroups according to atopy. MMP-7, MMP-9, MMP-13, tissue inhibitors of metalloproteinases (TIMPs), TIMP-1 and TIMP-2, myeloperoxidase (MPO), and human neutrophil elastase (HNE) were measured using enzyme-linked immunosorbent assay (ELISA), and MMP-8 was determined using immunofluorometric assay. High-sensitivity C-reactive protein (hs-CRP) was measured to estimate systemic involvement. RESULTS: Patients with asthma, CRSwNP, or both exhibited lower MMP-9, MMP-9/TIMP-1, MMP-9/TIMP-2, and MPO in nasal secretions (p < 0.05 in CRSwNP) and higher MMP-9, MMP-9/TIMP-1, MMP-9/TIMP-2, and HNE in serum (p < 0.05 in all groups) compared to controls, whereas no difference in MMP-7, MMP-13, TIMP-1, and TIMP-2 were detected. Atopy increased nasal MMP-9 and MPO expression. hs-CRP was higher in patients with CRSwNP and asthma compared to controls. CONCLUSION: Our findings suggest shared pathomechanisms behind asthma and CRSwNP. Contrasting local vs systemic results reflect a different ability of healthy mucosa to react to exogenous stimuli, possibly indicating a protective function of MMP-9 and possibly also MMP-8 in the airways.

Purification and characterization of tissue-type plasminogen activator in maxillary mucosa with chronic inflammation.

Tissue-type plasminogen activator (TPA) was purified from maxillary mucosa with chronic inflammation and compared with urokinase. Purification procedure consisted of the extraction from delipidated mucosa with 0.3M potassium acetate buffer (pH 4.2), 66% saturation of ammonium sulfate, zinc chelate-Sepharose, concanavalin A-Sepharose and Sephadex G-100 gel filtration chromatographies. The molecular weight of the TPA was approximately 58,000 +/- 3,000. Its activity was enhanced in the presence of fibrin and was quenched by placental urokinase inhibitor, but not quenched by anti-urokinase antibody. The TPA made no precipitin line against anti-urokinase antibody, while urokinase did. All these findings indicate that the TPA in maxillary mucosa with chronic inflammation is immunologically dissimilar to urokinase and in its affinity for fibrin.

IgG antibody levels in the sinus, ear, and airway in a rabbit model of sinusitis with Bacteroides.

OBJECTIVE: To evaluate distribution of IgG antibodies (Ab) in the airway, ear, and sinuses in association with inflammatory changes in a rabbit sinusitis model. DESIGN: We measured IgG Ab and lactate dehydrogenase levels in solutions from sinus, airway, and middle ear lavage and in serum, and determined interferon y messenger RNA expression in sinus and ear mucosa at 1, 2, 3, and 4 weeks after inoculation with Bacteroides fragilis. SUBJECTS: Six rabbits at each time point; controls were untreated (n=5) and sham-operated rabbits at 2 and 4 weeks (n=4-5). INTERVENTION: Bacteroides fragilis was inoculated into the left maxillary sinus with ostium closed. RESULTS: IgG Ab was undetectable in all controls. IgG Ab (>50 microg/g protein) was present at 2, 3, and 4 weeks in most bilateral sinus lavage samples and in 2 of 6, 5 of 6, and 6 of 10 ear lavage samples at 2, 3, and 4 weeks, respectively, following inoculation. Inflammatory changes (histological and lactate dehydrogenase) were much greater in the inflamed sinus. IgG Ab (>50 microg/g protein) was also detected in most bronchoalveolar lavage samples after 2 weeks. Interferon gamma mRNA was undetectable in all untreated and most sham-operated controls but was detected in the bilateral sinus mucosa at 1 to 2 weeks, and remained detectable up to 4 weeks in most rabbits. Serum IgG Ab levels positively correlated with those in lavage samples, with highest correlation with right sinus lavage IgG Ab levels (r=0.56, P<.001). CONCLUSION: IgG Ab levels in the upper airway mucosa likely increase within 2 weeks following bacterial inoculation as a part of mucosal immune responses independent of tissue necrosis.

Pathogenesis of sinus empyema.

The crucial event in the pathogenesis of sinus empyema is the ostial obstruction. On the basis of recent reports, some consequences of the obstruction on the local bacterial-host interrelationship have been outlined. The anaerobic gas environment of the empyema is one quality important to the selection of bacteria but probably also to the efficiency of the antibacterial activity of the granulocytes. Release of proteolytic enzymes from neutrophilic granulocytes in the sealed sinus may jeopardize the bacterial engulfment due to proteolytic degradation of opsonins. A longstanding exposure of the sinus mucosa to uninhibited proteolytic enzymes may explain the irreversible lesion of the mucosa in chronic sinusitis.

A protease inhibitor from human allergic nasal secretions.

Protease and antiprotease activities were estimated in nasal secretions from patients with chronic sinusitis and nasal allergy, using [3H]-casein as substrate. In the purulent nasal secretions, strong protease activity was measured, but there was less activity in the allergic nasal secretions. In contrast, trypsin inhibitory activity in allergic nasal secretions was much higher than in nasal secretions from the patients with chronic sinusitis. A protease inhibitor was partially isolated from nasal secretions of the nasal allergic patients by Sephadex G-150 gel chromatography and characterized. This protease inhibitor has an apparent molecular weight of 10,000 D, determined by SDS-polyacrylamidegel electrophoresis. It depresses the activities of bovine pancreatic trypsin, bovine pancreatic chymotrypsin and proteases in nasal purulent secretions, whereas it does not inhibit porcine pancreatic elastase, papain, or human plasmin.