Role of free radicals and antioxidants in nasal polyps

Association between Helicobacter pylori Infection and Nasal Polyps: A Systematic Review and Meta-Analysis

BACKGROUND

Helicobacter pylori (H. pylori) has definite or possible associations with multiple local and distant manifestations. H. pylori has been isolated from multiple sites throughout the body, including the nose. Clinical non-randomized studies with H. pylori report discrepant data regarding the association between H. pylori infection and nasal polyps. The aim of this first systematic review and meta-analysis was the assessment of the strength of the association between H. pylori infection and incidence of nasal polyps.

METHODS

We performed an electronic search in the three major medical databases, namely PubMed, EMBASE and Cochrane, to extract and analyze data as per PRISMA guidelines.

RESULTS

Out of 57 articles, 12 studies were graded as good quality for analysis. Male-to-female ratio was 2:1, and age ranged between 17-78 years. The cumulative pooled rate of H. pylori infection in the nasal polyp group was 32.3% (controls 17.8%). The comparison between the two groups revealed a more significant incidence of H. pylori infection among the nasal polyp group (OR 4.12), though with high heterogeneity I² = 66%. Subgroup analysis demonstrated that in European studies, the prevalence of H. pylori infection among the nasal polyp group was significantly higher than in controls, yielding null heterogeneity. Subgroup analysis based on immunohistochemistry resulted in null heterogeneity with preserving a statistically significant difference in H. pylori infection prevalence between the groups.

CONCLUSION

The present study revealed a positive association between H. pylori infection and nasal polyps.

Expression Levels of Glutathione S-Transferase and Cytochrome P450 Isoenzymes in Nasal Polyp Tissue

Nasal polyps are benign sinonasal masses composed of eosinophils and extracellular edema. Pathogenesis of the polyp formation is unclear but several studies strongly suggest a correlation with infection, inflammation and allergy conditions. Our aim is to investigate the potential link between allergy and nasal polyp in tissue level. Nasal polyp group included 60 patients whose diagnosis was confirmed with biopsy and the control group included 38 healthy patients. Tissue sample of the control group was taken from inferior turbinate mucosa under local anesthesia and nasal polyp tissue was collected from functional endoscopic sinus surgery. The glutathione S-transferase (GST) and cytochrome P450 (CYP) isoenzyme expressions of the tissue samples were investigated under light microscopy and graded by a senior pathologist. GSTP1 protein expression was significantly higher in tissue samples from nasal polyp group compared to that of control group (p < 0.05). However, CYP1A1, GSTM1 and GSTA1 isoenzymes were not different between the two groups (p > 0.05). We have found that GSTP1 isoenzyme was elevated in nasal polyp tissue compared to the control. The increase in protein expression of GSTP1 might have occured as a tissue response to the increased oxidative stress thus suggesting a role of GSTP1 in polyp formation.

Oxidative Stress and Antioxidants in Chronic Rhinosinusitis with Nasal Polyps

Oxidative stress results from an imbalance between the production of reactive oxygen species and the body's antioxidant defense system. It plays an important role in the regulation of the immune response and can be a pathogenic factor in various diseases. Chronic rhinosinusitis (CRS) is a complex and heterogeneous disease with various phenotypes and endotypes. Recently, an increasing number of studies have proposed that oxidative stress (caused by both environmental and intrinsic stimuli) plays an important role in the pathogenesis and persistence of CRS. This has attracted the attention of several researchers. The relationship between the presence of reactive oxygen species composed of free radicals and nasal polyp pathology is a key topic receiving attention. This article reviews the role of oxidative stress in respiratory diseases, particularly CRS, and introduces potential therapeutic antioxidants that may offer targeted treatment for CRS.

Hydrogen peroxide attenuates rhinovirus-induced anti-viral interferon secretion in sinonasal epithelial cells

Background

Altered innate defense mechanisms, including an imbalance between oxidants and antioxidants release, have been implicated in the pathogenesis of chronic rhinosinusitis (CRS). The aim of this study is to investigate whether oxidative stress may attenuate the secretion of anti-viral interferons in human sinonasal mucosa.

Methods

The levels of H₂O₂ in nasal secretion were increased in patients with CRS with nasal polyps, compared with that of CRS patients without nasal polyps and control subjects. Normal sinonasal epithelial cells derived from healthy subjects were cultured under an air-liquid interface. The cultured cells were infected with rhinovirus 16 (RV 16) or treated with poly (I: C), TLR3 agonist, after being pretreated with an oxidative stressor, H₂O₂ or antioxidant, N-acetylcysteine (NAC). Thereafter, the expression levels of type I (IFN-β) and type III (IFN-λ1 and λ2) interferons and interferon-stimulated genes (ISGs) were evaluated with RT-qPCR, ELISA, and western blot.

Results

The data showed that the production of type I (IFN-β) and type III (IFN-λ1 and λ2) interferons and ISGs was upregulated in cells infected with RV 16 or treated with poly (I: C). However, their up-regulated expression was attenuated in cells pretreated with H₂O_2, but not inhibited in cells pretreated with NAC. In line with these data, the up-regulated expression of TLR3, RIG-1, MDA5, and IRF3 was reduced in cells pretreated with H₂O_2, but not attenuated in cells treated with NAC. Furthermore, cells transfected with Nrf2 siRNA showed decreased secretion of anti-viral interferons whereas sulforaphane treatment enhanced the secretory capacity of antiviral interferons.

Conclusions

These results suggest that the production of RV16-induced antiviral interferons may be attenuated by oxidative stress.

Evaluation of Advanced Oxidation Protein Products (AOPP) and Superoxide Dismutase (SOD) Tissue Levels in Patients with Nasal Polyps

The aim of this study is to eveluate levels of advanced oxidation protein products (AOPP) which are thought to increase in the polyp tissue and superoxide dismutase (SOD), an antioxidant enzyme, with using specthrophotometry in polyp tissue and healthy mucosa. 30 nasal polyp patients without inflammatory disease except for nasal polyposis were included in the study. The control group consisted of 18 patients who did not have allergy, asthma, inflammatory and granulomatous disease and planned surgery due to septum deviation and concha hypertrophy. AOPP and SOD tissue levels were measured by spectrophotometry in polyp tissue specimens taken from patients with nasal polyps and concha samples taken from patients in the control group. The mean AOPP tissue level of patients in the nasal polyposis group was statistically significantly higher than the control group. (p < 0.05). The mean SOD activity level was significantly lower in the nasal polyposis group than the control group. (p < 0.05) As a result of this study, high AOPP levels in polyp tissue and low SOD levels in polyp tissue compared to healthy nasal mucosa, oxidative stress plays an important role in nasal polyp development.

Q192R polymorphism in the PON1 gene and nasal polyp in a Turkish population

The pathogenesis of nasal polyps is not completely understood. Oxidative damage contributes to polyp formation in the nasal mucosa. The paraoxonase 1 (PON1) enzyme is an important liver enzyme with high antioxidant activity. In this study, we investigated the correlation between Q192R genotypic polymorphism of the PON1 enzyme and nasal-polyp disease. The study examined 62 nasal-polyp patients and 88 controls. PON1 Q192R polymorphism was determined using polymerase chain reaction-restriction fragment length polymorphism. The genotype distribution of the PON1 gene was significantly different between nasal-polyp patients (QQ = 69.35%, QR = 25.81%, RR = 4.83%) and healthy controls (QQ = 52.27%, QR = 44.31%, RR = 3.40%). Our results suggest that the PON1 QQ genotype (odds ratio [OR] = 2.066, P = .036) is associated with a higher risk of developing the nasal-polyp disease while QR genotype (OR = 0.437, P = .021) showed a lower risk.

Cigarette Smoke Extract Stimulates MMP-2 Production in Nasal Fibroblasts via ROS/PI3K, Akt, and NF-κB Signaling Pathways

Cigarette smoke exposure has been shown to be associated with chronic rhinosinusitis and tissue remodeling. The present study aimed to investigate the effects of cigarette smoke extract (CSE) on matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) production in nasal fibroblasts and to determine the underlying molecular mechanisms. Primary nasal fibroblasts from six patients were isolated and cultured. After the exposure of fibroblasts to CSE, the expression levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured by real-time PCR, ELISA, and immunofluorescence staining. The enzymatic activities of MMP-2 and MMP-9 were measured by gelatin zymography. Reactive oxygen species (ROS) production was analyzed using dichloro-dihydro-fluorescein diacetate and Amplex Red assays. PI3K/Akt phosphorylation and NF-κB activation were determined by Western blotting and luciferase assay. CSE significantly increased MMP-2 expression and inhibited TIMP-2 expression but did not affect MMP-9 and TIMP-1 expression. Furthermore, CSE significantly induced ROS production. However, treatment with ROS scavengers, specific PI3K/Akt inhibitors, NF-κB inhibitor, and glucocorticosteroids significantly decreased MMP-2 expression and increased TIMP-2 expression. Our results suggest that steroids inhibit CSE-regulated MMP-2 and TIMP-2 production and activation through the ROS/ PI3K, Akt, and NF-κB signaling pathways in nasal fibroblasts. CSE may contribute to the pathogenesis of chronic rhinosinusitis by regulating MMP-2 and TIMP-2 expression.

Development of a microemulsion for encapsulation and delivery of gallic acid. The role of chitosan

A novel water-in-oil (W/O) microemulsion based on natural oils, namely extra virgin olive oil (EVOO) and sunflower oil (SO), in the presence of non-ionic surfactants was successfully formulated. The novel microemulsion was used as a carrier for gallic acid (GA) to assure its protection and efficacy upon nasal administration. The work presents evidence that this microemulsion can be used as a nasal formulation for the delivery of polar antioxidants, especially, after incorporation of chitosan (CH) in its aqueous phase. The structure of the system was studied by Small Angle X-ray Scattering (SAXS), Dynamic Light Scattering (DLS) and Electron Paramagnetic Resonance (EPR) spectroscopy techniques. By the addition of CH, the diameter of the microemulsion remained unaltered at 47 nm whereas after the incorporation of GA, micelles with 51 nm diameter were detected. The dynamic properties of the surfactant monolayer were affected by both the incorporation of CH and GA. Moreover, the antioxidant activity of the latter remained unaltered (99 %). RPMI 2650 cell line was used as the in vitro model for cell viability and for GA nasal epithelial transport studies after microemulsion administration. The results suggested that the nasal epithelial permeation of GA was enhanced, 3 h post administration, by the presence of 0.2 % v/v microemulsion in the culture medium. However, the concentration of the transported antioxidant in the presence of CH was higher indicating the polymer's effect on the transport of the GA. The study revealed that nasal administration of hydrophilic antioxidants could be used as an alternative route besides oral administration.

Expression of nicotinamide adenine dinucleotide phosphate oxidase in chronic rhinosinusitis with nasal polyps

BACKGROUND

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase produces reactive oxygen species (ROS) involved in oxidative stress and signal transduction. Recent studies have suggested that NADPH oxidase is associated with the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). The aim of this study was to detect the expression of NADPH oxidase subunits and 4-hydroxynonenal (4-HNE) in nasal polyp tissue and normal nasal mucosa, in order to explore the possible role played by NADPH oxidase in the pathogenesis of CRSwNP.

METHODS

Thirteen patients with CRSwNP and 9 normal control subjects were selected to participate in this study, in which we evaluated the expression of different NADPH oxidase subunits (gp91^phox , p67^phox , p47^phox , and p22^phox ) in nasal polyp (NP) tissue and control mucosa by Western blotting and real-time polymerase chain reaction (PCR). Immunohistochemistry and immunofluorescence staining were used to detect expression of the p67^phox subunit and 4-HNE in NP tissue and normal nasal mucosa.

RESULTS

Western blot and real-time PCR results showed that p67^phox expression was significantly increased in NP tissue when compared with its expression in control mucosa (p = 0.004). p67^phox was expressed in the eosinophils and neutrophils found in NP tissue, but not in the macrophages. Additionally, the levels of 4-HNE expression were also significantly increased in NP tissue when compared with control mucosa (p = 0.001).

CONCLUSION

The levels of p67^phox messenger RNA (mRNA) and protein as well as 4-HNE were both upregulated in NP tissue, suggesting that p67^phox and oxidative stress play roles in the pathogenesis of CRSwNP.

High PI3K/mTOR and low MAPK/JNK activity results in decreased apoptosis and autophagy in nasal polyposis

Introduction

Nasal polyposis is a progressive inflammatory disease that reduces the quality of life. The role of apoptotic and autophagic pathways in nasal polyposis pathogenesis is not yet clearly known.

Objective

In this study we aimed to investigate apoptotic (MAPK/JNK), anti-apoptotic (PI3K/mTOR) and autophagic (LC3) pathways which are related each other in the nasal polyposis tissues.

Methods

Twenty patients with nasal polyps and fifteen patients going through an inferior turbinate reduction were included in this study. Patients with asthma, Samter triad and allergic fungal sinusitis were excluded from the study. The apoptotic and autophagic pathways were investigated in paraffin-embedded nasal tissue sections of 20 NP and 15 samples from inferior turbinate reduction by H&E and immunohistochemistry with h-score. TUNEL method with apoptotic index was used to demonstrate apoptotic cells.

Results

Decreased immunoreactivity of P38 MAPK (p < 0.005) and JNK (p < 0.005) were observed in nasal polyposis compared to material from inferior turbinate reduction. This decrease may indicate a downregulation of apoptosis as demonstrated by decreased TUNEL staining in nasal polyposis (p < 0.005). The PI3K (p < 0.002) and mTOR (p < 0.005) immunoreactivities were increased in nasal polyposis. This increase indicates a downregulation of autophagy as demonstrated by decreased LC3 staining in nasal polyposis (p < 0.001).

Conclusion

Deficient apoptosis and autophagy through MAPK/JNK and PI3K/mTOR pathways may have a role in the pathogenesis of nasal polyposis.

Role of asthma and intolerance to acetylsalicylic acid on the redox profile in nasal polyp tissue

PURPOSE

Nasal polyposis is a chronic inflammatory disease of the mucosa of the nasal cavity and paranasal sinuses. The etiology of nasal polyposis is unclear; however, it may be associated with asthma and intolerance to acetylsalicylic acid, possibly altering the redox profile. The study intends to compare the redox profile in polyps surgically removed from three clinical groups of patients with nasal polyposis who were divided according to the presence of asthma and intolerance to acetylsalicylic acid.

METHODS

Patients were divided into three groups: nasal polyposis only (n = 30); nasal polyposis and asthma (n = 19); and nasal polyposis, asthma and intolerance to acetylsalicylic acid (n = 10). The following redox evaluations were performed: enzymatic antioxidant activity of superoxide dismutase, glutathione peroxidase, hydrogen peroxide consumption and glutathione S-transferase; non-enzymatic antioxidant levels of vitamin C, vitamin E and glutathione; levels of the oxidative damage biomarkers carbonyl groups (measuring protein damage) and malondialdehyde (measuring lipid peroxidation); and nitrite and nitrate levels.

RESULTS

Compared with the polyposis only group, hydrogen peroxide consumption, glutathione S-transferase, vitamin E and malondialdehyde were lower in the asthma group. Total glutathione (0.12 ± 0.01 vs. 33.34 ± 10.48 µmol/mg) and nitrite and nitrate (0.06 ± 0.01 vs. 15.95 ± 1.38 nmol/mg) levels were higher in the nasal polyposis, asthma and intolerance to acetylsalicylic acid group.

CONCLUSIONS

In patients with nasal polyposis, asthma may alter the redox profile associated with the hydrogen peroxide and lipid damage pathways, whereas asthma and intolerance to acetylsalicylic acid increase nitrite and nitrate and total glutathione levels.

Protein Biochip Array of Adhesion Molecule Expression in Peripheral Blood of Patients with Nasal Polyposis

Nasal polyposis is a chronic non-infectious inflammatory disease of the nasal and paranasal cavity mucosa of unknown multifactorial origin in which inflammatory cells, and in particular eosinophils, seem to play a pivotal role. Eosinophil migration from the bloodstream to nasal polyps is considered to be specific and is a complex process involving several different molecules such as ICAM-1, VCAM-1, and L-, P- and E-selectins. The aim of this study was to investigate, using a protein biochip array technology, the concentrations of these molecules in the peripheral blood of a group of patients affected by nasal polyposis. Patients exhibited a significantly higher expression of VCAM-1, E-selectin, and L-selectin compared to healthy controls, and Spearman's rank correlation test limited to the molecules with significant between-group differences demonstrated a significant correlation between VCAM-1 and E-selectin, VCAM-1 and L-selectin, and E-selectin and L-selectin. The results of this investigation are in line with those coming from various imunohistochemical analyses, and seem to confirm the role of inflammation in the pathogenesis of nasal polyposis. These molecules may also represent novel therapeutic targets in the treatment of nasal polyps, and may allow the selection of pharmacological prophylactics that would allow effective inhibition of the inflammation induced by a given allergen.

Genetic polymorphism of antioxidant enzymes in eosinophilic and non-eosinophilic nasal polyposis

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a chronic inflammatory disease of the paranasal sinuses, and its pathophysiology is not yet precisely known. It is suggested that oxygen free radicals play an important role in the pathogenesis of nasal polyposis. This study aimed to identify genetic polymorphisms of superoxide dismutase (SOD 2), catalase (CAT), and inducible nitric oxide synthase (iNOS) enzymes in eosinophilic CRSwNP and non-eosinophilic CRSwNP patients; the study also aimed to evaluate the effect of genetic polymorphism of antioxidant enzymes on CRSwNP etiopathogenesis. One hundred thirty patients, who received endoscopic sinus surgery due to CRSwNP, and 188 control individuals were included in this study. Nasal polyp tissues were divided into two groups histopathologically as eosinophilic CRSwNP and non-eosinophilic CRSwNP. Venous blood samples were taken from the patient and control groups. Polymorphisms in the Ala16Va1 gene, which is the most common variation of SOD-2 gene, and 21 A/T polymorphisms in catalase gene were evaluated with the restriction fragment length polymorphism method and -277 C/T polymorphism in the iNOS gene was evaluated with the DNA sequencing method. The GG genotype distribution for the (-277) A/G polymorphism in the iNOS gene was a statistically significant difference between eosinophilic CRSwNP and control groups (p < 0.05). The CC genotype distribution for the SOD2 A16V (C/T) polymorphism was not statistically significant in all groups (p > 0.05). The TT genotype distribution for the A/T polymorphism in catalase gene at position -21 was statistically significant differences in eosinophilic CRSwNP and control groups (p < 0.05). Increased free oxygen radical levels, which are considered effective factors in the pathogenesis of CRSwNP, can occur due to genetic polymorphism of enzymes in the antioxidant system and genetic polymorphism of antioxidant enzymes in eosinophilic CRSwNP patients might contribute to the pathophysiology.

Superoxide dismutase reduces the inflammatory response to Aspergillus and Alternaria in human sinonasal epithelial cells derived from patients with chronic rhinosinusitis

BACKGROUND

Aspergillus fumigatus and Alternaria alternata are ubiquitous environmental fungal allergens that can exacerbate airway inflammation and contribute to the disease process in patients with chronic rhinosinusitis (CRS). These antigens have been shown to induce human sinonasal epithelial cells (HSNECs) to promote a proinflammatory response, but what is unclear is a means by which to reduce these effects. Inhaled pathogens can induce HSNECs to produce reactive oxygen species (ROS) that trigger cytokine production.

OBJECTIVE

This study aimed to determine whether the free radical scavenger superoxide dismutase (SOD) could reduce HSNEC-derived inflammation, as measured by interleukin (IL)-6 and IL-8 production, in response to Aspergillus or Alternaria exposure.

METHODS

Sinus tissue explants were collected at the time of surgery from control patients (n = 7) and patients with CRS with nasal polyps (CRSwNP) (n = 9). HSNECs were cultured from the explants and treated with Aspergillus, Alternaria, and SOD for 24 hours. Cell supernatants and lysates were collected, and IL-6 and IL-8 concentrations were measured using enzyme-linked immunosorbent assay.

RESULTS

In control and CRSwNP HSNECs, Aspergillus and Alternaria both increased cytokine production (p < 0.05), as measured by IL-6 and IL-8 concentration. SOD treatment reduced the inflammatory response to fungal antigen exposure from CRSwNP HSNECs but not control HSNECs. In CRSwNP patients, SOD significantly decreased IL-6 and IL-8 production after Alternaria exposure and IL-8 after Aspergillus exposure (p < 0.05).

CONCLUSIONS

When HSNECs from CRSwNP patients are treated with SOD concurrently with Aspergillus or Alternaria, SOD treatment decreases the fungal antigen-induced inflammatory response. The ability to attenuate inflammation induced by common fungal allergens with SOD treatment could provide a novel therapeutic or preventative approach for patients with CRS or other allergic inflammatory airway diseases.

Ischemia-modified albumin, brain natriuretic peptide, and growth differentiation factor-15 levels in patients with nasal polyps

OBJECTIVE

Nasal polyps (NP) are a chronic inflammatory disease of the nasal mucosa; their etiology is suspected to involve oxidative stress. Growth differentiation factor-15 (GDF-15), brain natriuretic peptide (BNP), and ischemia-modified albumin (IMA) are biomarkers used especially in the early diagnosis and follow-up of cardiovascular diseases. The aim of this study was to assess levels of serum GDF-15, BNP, and IMA in patients with NP and to compare them with those of healthy subjects.

METHODS

This was a prospective study enrolling 41 patients with NP and 48 healthy controls, all aged 18-65 years and referred to the Department of Otorhinolaryngology, Head and Neck Surgery, between January 2014 and February 2015. After a 12-h fast, venous blood (3mL) was drawn and centrifuged (3000rpm, 10min) to collect serum. Blood samples were drawn before endoscopic sinus surgery in the NP group. Serum GDF-15, BNP, and IMA levels were measured.

RESULTS

GDF-15, BNP, and IMA levels of patients with NP were statistically significantly higher than in controls and GDF-15 values were higher than the normal upper limit. GDF-15, BNP, and IMA levels were significantly correlated in both groups.

CONCLUSIONS

As GDF-15 is a marker of chronic inflammation and oxidative stress, our finding of increased serum GDF-15 in patients with NP supports the hypothesis that its pathogenesis involves chronic inflammation and oxidative stress.

The 100 Most Cited Turkish Papers in the Otorhinolaryngology Journals of Web of Science

Objective

The aim of the study was to analyze the 100 most cited publications with Turkish origin in the Web of Science Otorhinolaryngology (ORL) journals.

Methods

The Web of Science database was searched in terms of citations for publications originating from Turkey in ORL journals since 1983. After the identification of the 100 most cited articles, analysis was performed for the first author, institution, city, publication type, subject related to subspecialty, and journals having the most cited articles. Moreover, the number of ORL publications and citations of countries was determined in descending order using the same database.

Results

A total of 3948 ORL articles with Turkish origin was identified. The number of citations was 181 for the first and 28 for the last in the 100 most cited articles. As there was more than one article with 28 citations, 101 articles were analyzed. The number of the articles was 76, 22, and 3 for the university, education/research, and state hospitals, respectively. Hacettepe University, Ankara Numune Hospital, and Gazi University were the three leading institutions having the most cited articles, and Ankara was the first city. While 98 of 101 articles were original research, the number of case reports and review articles were 2 and 1, respectively. Thirty-five articles were related to otology, 23 to pediatric ORL, 20 to rhinology and head and neck surgery, and 3 to facial plastic surgery. Laryngoscope, Otolaryngology-Head and Neck Surgery, and International Journal of Pediatric Otorhinolaryngology were the leading 3 journals with the most cited articles coming from Turkey. The evaluation of countries revealed that Turkey was among the first 10 countries in terms of number of ORL articles but fell behind for the number of citations.

Conclusion

This bibliometric study is the first one regarding the contribution of Turkish authors and institutions to ORL literature. Similar studies might be periodically repeated to determine national development in the field of ORL and place of Turkey in the world.

Does aspirin-induced oxidative stress cause asthma exacerbation?

Aspirin-induced asthma (AIA) is a distinct clinical syndrome characterized by severe asthma exacerbations after ingestion of aspirin or other non-steroidal anti-inflammatory drugs. The exact pathomechanism of AIA remains unknown, though ongoing research has shed some light. Recently, more and more attention has been focused on the role of aspirin in the induction of oxidative stress, especially in cancer cell systems. However, it has not excluded the similar action of aspirin in other inflammatory disorders such as asthma. Moreover, increased levels of 8-isoprostanes, reliable biomarkers of oxidative stress in expired breath condensate in steroid-naïve patients with AIA compared to AIA patients treated with steroids and healthy volunteers, has been observed. This review is an attempt to cover aspirin-induced oxidative stress action in AIA and to suggest a possible related pathomechanism.

Oxidative stress and nasal polyposis: does it affect the severity of the disease?

BACKGROUND

Nasal polyposis (NP) is a chronic inflammatory disease and the waste products of this inflammation are reactive oxygen species composed of free radicals. Changes in oxidative status have already been revealed in NP. The aim of this study was to investigate the effect of oxidative status to the severity of the disease and the quality of life.

METHODS

The study group included 24 patients with NP and 20 controls. The Turkish version of the Rhinosinusitis Disability Index, visual analog scale (VAS), polyp stage, computed tomography (CT) score, and the eosinophilic cationic protein (ECP) levels in nasal lavage (NAL) fluid were used to assess the severity of the disease. Malondialdehyde, nitric oxide (NO), and the total antioxidant status (TAS) levels in NAL fluids were measured representing the oxidative stress.

RESULTS

NO values were correlated with nasal congestion (p = 0.031). TAS values were correlated with nasal obstruction (p = 0.039). ECP values showed correlation with all the nasal obstruction (p = 0.003), congestion (p = 0.009), rhinorrhea (p = 0.009), and VAS scores (p = 0.039).

CONCLUSION

In NP, ECP levels detected in NAL fluid were significantly high and were correlated with the severity of the disease. Moreover, the severity of oxidative stress, in the forms of TAS and NO, is significantly correlated with the severity of the nasal obstruction and congestion, respectively.

Evaluation of oxidative DNA damage and antioxidant defense in patients with nasal polyps

OBJECTIVES

The presence of inflammatory cells indicates the development of epithelial cell injury in nasal polyposis (NP) and the potential for production of high levels of reactive oxygen and nitrogen species. The aim of our study was to clarify the role of oxidative stress and antioxidant status in the deterioration accompanying NP.

METHODS

Twenty patients (11 men) aged 47.2 ± 17.0 years with nasal polyps were included in the study. Twenty healthy subjects (7 men) aged 48.2 ± 15.3 years formed the control group. The erythrocyte activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and plasma nitric oxide (NO) concentrations were measured. An alkaline comet assay was used to determine the extent of blood lymphocyte DNA damage of oxidized purines as glicosylo-formamidoglicosylase (Fpg) sites, and oxidized pyrimidines as endonuclease III (Nth) sites.

RESULTS

A significant increase of NO (P < 0.05) and non-significant decreases of SOD (P > 0.05), CAT (P > 0.05), and GPx (P > 0.05) were seen in NP patients compared to healthy controls. The level of blood lymphocyte oxidative DNA damage in NP patients was significantly higher compared to the control group (P = 0.01).

DISCUSSION

The blood lymphocyte DNA damage level increased in patients with NP. Elevated DNA damage may be related to overproduction of reactive oxygen and nitrogen species and/or decreased antioxidant protection.

Role of caffeic Acid on collagen production in nasal polyp-derived fibroblasts

Objectives

Caffeic acids are known to have anti-oxidant, anti-inflammatory, immunomodulatory, and tissue reparative effects. The purposes of this study were to determine the effect of caffeic acid on transforming growth factor (TGF) β1-induced myofibroblast differentiation and collagen production, and to determine whether caffeic acid is involved in the antioxidant effect in nasal polyp-derived fibroblasts (NPDFs).

Methods

NPDFs were pretreated with caffeic acid (1-10 µM) for 2 hours and stimulated with TGF-β1 (5 ng/mL) for 24 hours. The expression of α-smooth muscle actin (SMA), collagen types I and III, and Nox4 mRNA was determined by a reverse transcription-polymerase chain reaction, and the expression of α-SMA protein was determined by actin ned by immunofluorescence microscopy. The amount of total soluble collagen production was analyzed by the Sircol collagen dye-binding assay. The reactive oxygen species (ROS) generated by NPDFs were determined using 2',7'-dichlorfluorescein-diacetate. siNox4 was used to determine the effect of Nox4.

Results

The expression of α-SMA and production of collagen were significantly increased following TGF-β1 treatment. In contrast, the level of expression of α-SMA and the level of production of collagen were decreased by pretreatment with caffeic acid. The activation of Nox4 and the subsequent production of ROS were also reduced by pretreatment with caffeic acid. The expression of α-SMA was prevented by inhibition of ROS generation with siNox4.

Conclusion

Caffeic acid may inhibit TGF-β1-induced differentiation of fibroblasts into myofibroblasts and collagen production by regulating ROS.

Staphylococcus aureus enterotoxin B-induced endoplasmic reticulum stress response is associated with chronic rhinosinusitis with nasal polyposis

OBJECTIVE

Staphylococcus aureus enterotoxin B (SEB) might participate in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). However, the exact mechanism of polyp formation in CRSwNP remains unclear. Since the endoplasmic reticulum (ER) stress response is closely associated with chronic inflammation, we investigated the association between ER stress and SEB in the pathogenesis of CRSwNP.

DESIGN AND METHODS

Twenty-three CRSwNP patients with eosinophilic polyps (EP) or non-eosinophilic polyps (NEP) and 10 healthy subjects who were undergoing septoplasty were enrolled in this study. ER stress response was investigated using immunohistochemical staining and Western blotting.

RESULTS

We show in this study that there are significantly more SEB-positive cells and higher production of reactive oxygen species (ROS) in the epithelial layer of EP than NEP or control tissue. Both SEB and protein A were detected strongly in tissues from patients with CRSwNP. We observed SEB induced the ER stress response in RPMI 2650 cells. GRP78 elevation by SEB was reduced by ROS scavenger pretreatment. In addition, the induction of GRP78 and p47 phox was increased significantly in EP compared with NEP or control mucosa.

CONCLUSIONS

SEB may induce ER stress via ROS production in CRSwNP. Therefore, we suggest that SEB-induced ER stress may play important roles in the pathogenesis of nasal polyposis.

Evaluation of ceruloplasmin levels in patients undergoing surgical interventions with nasal polyps

OBJECTIVE

Oxidative stress is believed to have a role in the development of nasal polyps (NPs). It is also known that ceruloplasmin (CP), an acute phase protein, limits oxidative stress. The purpose of this study was to evaluate the ceruloplasmin levels in patients with NPs.

METHODS

One hundred and twenty patients with NPs, septal deviations and concha hypertrophies were recruited to the study. Patients were divided in two groups; group 1 (n=60) consisted of patients with NPs, and group 2 (n=60) consisted of septal deviations and concha hypertrophies. Polyp specimens were taken from all patients who underwent endoscopic surgery due to NPs, as well as control specimens were acquired who underwent an operation due to septoplasty or concha hypertrophy. Blood and tissue samples were obtained to assess CP levels.

RESULTS

There were no statistical differences in gender, age and biochemical values between two groups (p>0.05 for all). Compared to group 2, group 1 had significantly higher CP levels both in serum and the tissue samples (both p<0.001).

CONCLUSION

As a result of our study; CP levels both in serum and the tissue in patients with NPs were higher, may be consequence of the inflammation, than in patients without NPs.

Effect of [6]-gingerol on myofibroblast differentiation in transforming growth factor beta 1-induced nasal polyp-derived fibroblasts

BACKGROUND

[6]-Gingerol is one of the major pungent principles of ginger and has diverse effects, including anti-inflammatory, and antioxidative effects. Reactive oxygen species (ROS) are released during the phenotypic transformation of fibroblasts to myofibroblasts, a process that is involved in the growth of nasal polyps by inducing extracellular matrix (ECM) accumulation. The purpose of this study was to determine the effect of [6]-gingerol on myofibroblast differentiation and collagen production of nasal polyp-derived fibroblasts (NPDFs) and to determine if the effect of [6]-gingerol is linked to an antioxidant effect.

METHODS

NPDFs were incubated and treated with transforming growth factor (TGF) beta 1. The ROS generated by NPDFs were determined using 2″,7″-dichlorfluorescein-diacetate. The fluorescence was captured by a fluorescent microscope and measured using a fluorometer. The expression of alpha-smooth muscle actin (SMA) and collagen type IV mRNA was determined by a reverse transcription-polymerase chain reaction, and the expression of α-SMA protein and pSmad2/3 was determined by immunofluorescence microscopy and or Western blotting. The amount of total soluble collagen production was analyzed by the SirCol collagen dye-binding assay.

RESULTS

TGF-beta 1 stimulation increased ROS production by NPDFs. [6]-Gingerol decreased the production of ROS in TGF-beta 1-induced NPDFs. Myofibroblast differentiation, collagen production, and phosphorylation of Smad2/3 were prevented by [6]-gingerol and inhibition of ROS generation with antioxidant such as diphenyliodonium, N-acetylcysteine, and ebselen.

CONCLUSION

These results suggest the possibility that [6]-gingerol may play an important role in inhibiting the production of the ECM in the development of nasal polyps through an antioxidant effect.

Effect of antioxidants on the clinical outcome of patients with nasal polyposis

AIM

To investigate the therapeutic effects of antioxidants on the clinical and biochemical outcome of patients with nasal polyposis.

METHODS

Thirty-four patients with nasal polyposis were divided into two groups receiving either intranasal steroid or intranasal steroid plus per-oral vitamins A, C and E and selenium. Paranasal sinus computed tomography, endoscopy, and polyp tissue and serum sampling were conducted pre- and post-therapy. Serum levels of malondialdehyde, superoxide dismutase, nitrite and myeloperoxidase and tissue levels of malondialdehyde and superoxide dismutase were measured. Group results were compared using the Mann-Whitney U test and Wilcoxon signed-rank test.

RESULTS

Both groups had significantly lower tissue parameters, computed tomography scores and serum malondialdehyde levels, comparing pre- versus post-treatment results. Post-treatment, the steroid plus antioxidant group had significantly lower tissue malondialdehyde levels and a greater fall in tissue and serum malondialdehyde, compared with the steroid group.

CONCLUSION

Serum and tissue levels of malondialdehyde (an oxidative marker) were significantly decreased by adding antioxidants to standard therapy. This is the first report of the positive effects of adding antioxidants to steroid therapy for nasal polyposis.

Iron homeostasis and methionine-centred redox cycle in nasal polyposis

Nasal polyposis is a multifactorial disease with a strong inflammatory component. Its pathogenesis is often associated with ROS production catalysed by redox-active iron. This study aimed to characterize the roles of iron homeostasis and redox status in the pathogenesis of polyposis. Nasal polyps (NP) from asthmatics and non-asthmatics and turbinates from controls and NP-patients were analysed for ferritin, ferritin-bound iron (FBI) and levels of methionine-centred redox cycle proteins. The ferritin content in both NPs was significantly higher than in adjacent turbinates. No differences in FBI were observed between both NP groups and both turbinates groups, while in NPs it was significantly higher. In NP-turbinates the highest levels of redox proteins were observed. In conclusion, re-distribution of iron occurs upon the development of NP. While FBI is elevated in NPs, the adjacent turbinate remain iron-poor and low-inflammatory, suggesting the formation of virtual boundary between these tissues.

Overexpression of the superoxide anion and NADPH oxidase isoforms 1 and 4 (NOX1 and NOX4) in allergic nasal mucosa

BACKGROUND

The purpose of this study was to investigate the expression and distribution of superoxide anion, NADPH oxidase (NOX)1, and NOX4 in healthy, allergic nasal mucosa and nasal polyps to evaluate the possible influence of oxidative stress on the development of allergic rhinitis and nasal polyps.

METHODS

The expression and distribution of superoxide anion, NOX1 and NOX4 were evaluated in healthy and allergic nasal mucosa and nasal polyps, using dihydroethidium fluorescence, semiquantitative reverse transcriptase-polymerase chain reaction, immunohistochemistry, and Western blot.

RESULTS

NOX1 and NOX4 were localized mainly in the epithelial layer, submucosal glands, vascular endothelium, and inflammatory cells in healthy and allergic nasal mucosa and nasal polyps. The cellular source that generated superoxide anion is also localized in the epithelial cells, submucosal glands, vascular endothelium, and inflammatory cells, demonstrating the similar sites of expression of NOX1 and NOX4 in healthy and allergic nasal mucosa and nasal polyps. NOX1 and NOX4 mRNA and proteins and superoxide anions had increased levels of expression in allergic nasal mucosa and nasal polyps compared with healthy nasal mucosa.

CONCLUSIONS

These results indicate that NOX1 and NOX4 may play an important role in reactive oxygen species production, contributing to the oxidative stress in allergic rhinitis and nasal polyp tissues.

The glutathione-S-transferase gene polymorphisms (Gstt1, Gstm1, and Gstp1) in patients with non-allergic nasal polyposis

There is an ongoing dilemma about the pathogenesis of nasal polyp (NP). The etiology of NP is multifactorial. Reactive oxygen species and oxidative stress are also suggested to be among the possible factors in NP development. Glutathione-S-transferase (GST) is one of the important detoxifying enzymes. It is not known whether GST plays any role in NP development. We aimed to investigate the relationship between GST subgroup (GSTT1, GSTM1, and GSTP1) polymorphisms, and NP development. Seventy-five patients with NP with or without asthma (NP with asthma: 22, NP without asthma: 53) were used as a study group. As much as 167 healthy individuals were involved as the control group. NP diagnosis was made by nasal endoscopy and paranasal sinus computed tomography (CT). NP was defined as the presence of endoscopically visible bilateral polyps originated from the middle meatus to the nasal cavity and affecting more than one paranasal sinus confirmed by CT. Blood was collected in EDTA-containing tubes and DNA was extracted from the leukocytes. The genotyping of polymorphisms of GSTT1, GSTM1, and GSTP1 were done using real time polymerase chain reaction. Chi-square (chi(2)) and Fisher's (F) exact tests were used for statistical evaluation. A 2-fold increased risk of NP could be found in individuals with the GSTT1 null genotype (OR = 2.03, 95% CI = 1.03-4.011). The distribution of GSTM1 null genotypes was not significantly different between the NP patients and controls and there was also no significance between the GSTP1 genotypes and NP. In conclusion, GST gene polymorphisms may be important in pathogenesis of NP. Additional studies which include larger study groups in different geographic localizations may be more useful to evaluate association with GST polymorphism and NP.

Expression of glutaredoxin-1 in nasal polyps and airway epithelial cells

BACKGROUND

Glutaredoxins (GRX)-1 is glutathione-dependent oxidoreductase. However, the role of these enzymes remains unknown in airway inflammatory diseases. Therefore, we aimed to establish the expression pattern of GRX-1 in the nasal polyps (NPs) and to assess the regulatory mechanisms associated with GRX-1 expression in interleukin (IL)-1 beta-treated airway epithelial cells.

METHODS

The expression of GRX-1 in NPs and normal nasal mucosa were analyzed by reverse-transcription polymerase chain reaction and immunohistochemical staining. IL-1 beta-induced reactive oxygen species (ROS) formation and GRX-1 expression in the airway epithelial cells was determined by flow cytometry and immunoassay.

RESULTS

The expression level of GRX-1 in NPs was significantly higher than in the normal nasal mucosa (p < 0.05). GRX-1 was highly expressed in the surface epithelial cells and the submucosal glandular cells in the NPs. IL-1 beta increased the intracellular ROS formation and GRX-1 expression in airway epithelial cells. The inhibition of IL-1 beta-induced ROS production by N-acetyl-cystein, an ROS scavenger, reduced GRX-1 expression. Diphenyleneiodonium and apocynin, NADPH oxidase inhibitors, did not abolish IL-1 beta-induced ROS formation and GRX-1 expression, whereas budesonide attenuated it.

CONCLUSION

High GRX-1 expression in NPs might be a primary defense against chronic inflammatory oxidative stress in nasal mucosa. IL-1 beta-induced up-regulation of GRX-1 in airway epithelial cells is probably mediated by ROS. Glucocorticoids can regulate IL-1 beta-induced ROS formation and GRX-1 expression.

The association of oxidative stress and nasal polyposis

Many diseases are linked to damage from reactive oxygen species that occurs from an imbalance between reactive oxygen species and antioxidants, a condition called oxidative stress. Nasal polyposis is considered to be an inflammatory condition in nasal and paranasal sinus cavities and its aetiology is still unclear. There are very few data on epithelial changes in nasal polyposis and their relationship with free radical damage. Malondialdehyde as a major end-product of lipid peroxidation, and superoxide dismutase and nitric oxide as antioxidants play important roles in oxidative stress. In this study, the concentrations of malondialdehyde, superoxide dismutase and nitric oxide were compared in normal and nasal polyposis-affected tissue samples. Malondialdehyde levels were significantly higher, and superoxide dismutase and nitric oxide levels were significantly lower in patients with nasal polyposis compared with the control group. This study demonstrates that there is a strong relationship between oxidative stress and the pathogenesis of nasal polyposis.

Alteration of mitochondrial DNA sequence and copy number in nasal polyp tissue

This study was designed to investigate the possibility that mtDNA mutations might arise in inflammatory or chronically damaged nasal polyp tissue from 23 patients. Thirteen patients (57%) displayed nasal polyp tissue-specific mtDNA mutations in the hypervariable segment of the control region and cytochrome b gene, which were not found in the corresponding blood cells and/or adjacent normal tissue. Nasal polyp tissue-specific length heteroplasmic mutations were also detected in nucleotide position (np) 303-315 homopolymeric poly C track (39%), np 514-523 CA repeats (17%) and np 16184-16193 poly C track (30%). The average mtDNA copy number was about three times higher in nasal polyp tissue than in the corresponding peripheral blood cells and adjacent non-polyp tissues. The level of reactive oxygen species (ROS) was significantly higher in the nasal polyp tissues compared to those from the corresponding samples. High level of ROS in nasal polyp tissue may contribute to development of mtDNA mutations, which may play a crucial role in the vicious cycle of pathophysiology of nasal polyps.

Oxidative stress in nonallergic nasal polyps associated with bronchial hyperresponsiveness

BACKGROUND

Nasal polyposis (NP) is a chronic inflammatory disease of upper airway with unknown etiology. NP is frequently associated with asthma; the interaction between these comorbidities remains interesting. Oxidative stress has been implicated in the pathophysiology of NP and asthma. The aim of this study is to investigate the significance of oxidative stress in sinonasal microenvironments by evaluating its association with clinopathological parameters and its impacts on the pathogenesis of bronchial hyperresponsiveness (BHR) in NP.

METHODS

Polyp biopsy specimens were obtained from 20 nonallergic patients; control mucosas were obtained from 20 volunteers. The levels of free radicals in the tissues and in blood were determined by a sensitive chemiluminescence (CL) method. NP patients were substratified into three subgroups, NP without BHR, NP with asymptomatic BHR, and NP with BHR and asthma by the results of provocative testing. Four histological characteristics of NP, inflammatory cells, eosinophil infiltration, edema and fibrosis were estimated and applied to correlate with the tissue-CL.

RESULTS

The mean CL level in polyp-tissues, but not in blood, was higher than in the control specimens. In NP patients, tissue-CL was associated with endoscopy score; high tissue-CL levels were positively correlated with the abundance of inflammatory cells and eosinophils. Tissue-CL and endoscopy score were associated with BHR/asthma phenotype.

CONCLUSION

These results suggest an important role for oxidative stress in the pathophysiology of NP and a causal relation between oxidative stress and inflammatory cells, especially the eosinophils. Free radical levels in polyp-tissues associated with NP severity and with BHR/asthma phenotype in nonallergic NP patients.

Lipid peroxidation and some antioxidant enzymes in nasal polyp tissue

Nasal polyp (NP) is considered an inflammatory condition in nasal and paranasal sinus cavities and is frequently encountered in otolaryngology clinics. Although the pathophysiology of nasal polyps is poorly understood, it seems likely that the epithelium may play a critical role in the genesis of inflammatory nasal disease. The aim of this study was to investigate the role of free radicals and antioxidant enzymes in NP and compare these findings with concha bullosa (CB). NP and CB were obtained from 27 and 23 patients, respectively. Glutathione peroxidase (GSH-Px), catalase (CAT), xanthine oxidase (XO) total (enzymic plus non-enzymic) superoxide scavenger activity (TSSA), non-enzymic superoxide scavenger activity (NSSA), superoxide dismutase (SOD), and MDA levels in NP and CB were measured. GSH-Px activiy was significantly lower in patients with NP than in the CB group. However, CAT, XO activities and MDA levels were significantly higher in patients with NP than in the CB group, but TSSA, NSSA and SOD activities were unchanged. Increases in the levels of tissue MDA in patients with NP compared to the CB group may indicate the presence of free radical damage in patients with nasal NP.

Altered expression profile of superoxide dismutase isoforms in nasal polyps from nonallergic patients

OBJECTIVE/HYPOTHESIS

Nasal polyposis (NP) is a chronic inflammatory disease of the upper respiratory tract. The pathophysiology is unknown but has been shown to be multifactorial. Free radical-mediated damage has been implicated in the pathogenesis of NP. Superoxide dismutases (SODs) are the first and the most important line of antioxidant enzyme defense against reactive oxygen species. Moreover, isozymes of the SOD family are critical for modulating the activity of nitric oxide, a gaseous free radical that is believed to play roles in the physiology and pathology of respiratory tracts. However, the expression profile of SOD isoforms in NP remains unclear. We aimed to investigate the expression profile of the SOD isoforms in nasal polyps from nonallergic patients.

STUDY DESIGN

Prospective study.

METHODS

Nasal polyp tissues were obtained from eight nonallergic patients who underwent elective polypectomy; mucosal specimens from the middle turbinates were acquired from eight subjects without NP as control tissues. The expression profile of SOD isoenzymes, SOD1, SOD2, and SOD3, in the nasal tissues was determined by reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and Western blotting (WB).

RESULTS

NP in all eight of the NP patients manifested as severe or recurrent sinonasal polyposis clinically. The expression pattern of SOD isoenzymes evaluated by RT-PCR analysis indicated that the mean levels of SOD1 mRNA and, to a greater extent, SOD3 mRNA were higher in polyp tissues than in control tissues. There was no significant difference in the expression levels of SOD2 mRNA between the two groups. The data from ELISA and WB analysis showed that there were increased expressions of SOD1 and SOD3 protein in polyp tissues compared with the control tissues, but there was no difference in the expression of SOD2 protein between the two groups. The results from RT-PCR, ELISA, and WB were paralleled and revealed that the expressions of SOD1 and, to a greater extent, SOD3 were higher in polyp tissues than in the control group.

CONCLUSIONS

The expressions of SOD3 and SOD1 were higher in polyp tissues. These results are consistent with previously reported data and support the hypothesis that there is increased oxidative stress in NP. Our data also suggest that the SODs might be important in the pathogenesis of NP; however, the roles these SOD isoforms, especially SOD3, play in both normal nasal mucosa and NP require further clarification.

Malondialdehyde level and adenosine deaminase activity in nasal polyps

OBJECTIVE

Although there are many reports on adenosine deaminase (ADA) activities in different tissues, no information is available about the enzyme activity in nasal mucosa and polyp tissues. Whereas ADA is related to the production of free radicals by neutrophils, malondialdehyde (MDA) is an indicator of lipid peroxidation that is a general mechanism of tissue damage by free radicals. This study is aimed at determining and comparing the ADA activity and MDA level in nasal polyps and normal mucosa.

STUDY DESIGN AND SETTING

Twenty-three patients with nasal polyps and a control group consisting of 14 patients with septal deviation and lower turbinate hypertrophy were included in the study. Tissue MDA level was measured by the method of Okawa with modification and tissue ADA activity by the method of Giusti.

RESULTS

In patients with nasal polyp, mean tissue MDA level and ADA activity were 2.43 +/- 0.38 nmol/mg protein (Pr) and 0.235 +/- 0.055 U/mg Pr, respectively, which were significantly higher than those of control nasal mucosa (1.03 +/- 0.41 nmol/mg protein and 0.056 +/- 0.011 U/mg Pr, respectively) (P < 0.05). In addition, tissue MDA level was positively correlated to ADA activity in nasal polyps (r = 0.701, P < 0.001).

CONCLUSIONS

The present study showed the presence of detectable ADA activity in nasal mucosa, and also significant increases in both tissue MDA level and ADA activity in NP tissue when compared to normal turbinate tissue.

EBM RATING

B-2b.

Expression and distribution of thioredoxin and thioredoxin reductase in human nasal mucosa and nasal polyp

CONCLUSIONS

The results of this study indicate that thioredoxin (Trx) and thioredoxin reductase (TrxR) may play a role in the defense of normal human nasal mucosa against external noxious stimuli. Based on the fact that normal nasal mucosa is continuously exposed to inhaled toxicants and contains a considerable number of inflammatory cells, Trx and TrxR may be upregulated even in normal nasal mucosa and perhaps the difference in their expression levels between normal nasal mucosa and nasal polyp, if it exists at all, is small and therefore difficult to detect. Further studies will be needed to clarify the roles of Trx and TrxR in the pathogenesis of nasal polyp.

OBJECTIVES

The cellular antioxidant defense system includes thiol-containing proteins such as Trx and TrxR, which have recently attracted much attention due to their strong antioxidant radical quenching capabilities and other important biological functions related to the regulation of the cellular redox state. This study was undertaken to investigate the expression and distribution of Trx and TrxR in normal human nasal mucosa and nasal polyp, and to improve understanding of the significance of the Trx system in these conditions.

MATERIAL AND METHODS

The expression and distribution of Trx and TrxR in normal human inferior turbinate mucosa and nasal polyp were investigated using reverse transcriptase polymerase chain reaction (RT-PCR), semiquantitative RT-PCR, Western blotting and immunohistochemistry.

RESULTS

mRNAs and protein for both Trx and TrxR were detected in normal human inferior turbinate mucosa and nasal polyp. Semiquantitative RT-PCR and Western blotting revealed that there was no significant difference in the expression levels of Trx and TrxR between inferior turbinate mucosa and nasal polyp. Immunoreactivity for both Trx and TrxR was seen in nasal epithelial cells, glands and vascular endothelium of inferior turbinate mucosa and nasal polyp. Trx and TrxR immunoreactivity was also found in inflammatory infiltrating cells in inferior turbinate mucosa and nasal polyp.