The Association of Oxidative Stress and Nasal Polyposis

E EKIN 0 OM IPCIOGLU 0 BE ERKUL 0 B KAPUCU 0 O OZCAN 0 H CINCIK 0 A GUNGOR 0 0 Dr Engin ekin GATA, Haydarpasa Egitim Hastanesi, KBB Klinigi, 34668 Kadky, Istanbul, Turkey - Downloaded from imr.sagepub.com by guest on October 16, 2014 The Journal of International Medical Research 2009; 37: 325 330 [first published online as 37(2) 2] The Association of Oxidative Stress and Nasal Polyposis 1Department of Otolaryngology, and 2Department of Biochemistry, Gulhane Military Medical Academy, Haydarpasa Training Hospital, Istanbul, Turkey 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. Introduction Nasal polyposis is considered an inflammatory condition in nasal and paranasal sinus cavities and is often encountered in otolaryngology clinics. Despite the prevalence and recognition of this condition for 3000 years, its aetiology has remained unclear. There have been many suggestions about the aetiology of nasal polyposis, including adenoma, fibroma, glandular cyst, mucosal exudates, blockade, glandular hyperplasia, new gland formation, ion transport, periphlebitis, perilymphangitis, cystic dilatation of the excretory duct, vessel obstruction and necrotizing ethmoiditis; however multiple factors may be involved in polyp formation and the precise aetiology of nasal polyposis is still unknown.1,2 Most studies in the literature deal with the inflammatory mechanisms occurring in the lamina propria of nasal polyposis, but few data are available on epithelial changes and their relationship with free radical damage.3 The nasal epithelium represents the respiratory systems first line of defence against inhaled stimuli, such as chemical pollutants and allergens, and is thought to have an important role in the regulation of nasal inflammatory disease through the Downloaded from imr.sagepu3b.c2om5by guest on October 16, 2014 release of cytokines, platelet-activating factor and prostanoids, and the expression of adhesion molecules. Resultant free radical damage to lipids (peroxidation), proteins and DNA leads to various forms of cell injury.4 An important mechanism in the development of cell injury due to reactive oxygen species is lipid peroxidation of polyunsaturated fatty acids in cell membranes, which forms products such as malondialdehyde, an end-product of lipid peroxidation. Many diseases are linked to damage from reactive oxygen species that occurs from an imbalance between reactive oxygen species and scavenging systems (antioxidants), i.e. oxidant/antioxidant imbalance, a condition known as oxidative stress. Superoxide dismutase that catalyses the dismutation of superoxide anions is the first and the most important line of antioxidant enzyme defence against reactive oxygen species. The isozymes of the superoxide dismutase family are crucial for modulation of the activity of nitric oxide, a gaseous free radical believed to play a role in the physiology and pathology of the respiratory tract and an important regulator of several biological functions. Nitric oxide is known to be produced from various types of cells and tissues in response to inflammatory stimulation and to be an important regulator of immune surveillance, including antiviral and bactericidal effects; however, nitric oxide also inhibits cell proliferation, DNA synthesis and collagen production.5 9 Previous studies have reported decreased nasal nitric oxide levels in patients with chronic rhinosinusitis and nasal polyposis in general, and also in patients with cystic fibrosis, even before the onset of chronic respiratory tract infections.10,11 Nitric oxide is generated from arginine by a family of enzymes known as the nitric oxide synthases, and acts as an autocrine and paracrine messenger. It also has an important role in non-specific host defence because of its cytotoxicity toward tumour cells and micro-organisms. Since nitric oxide and oxygen both contain an unpaired electron, they rapidly react together, leading to their reciprocal inactivation and eventually the formation of peroxynitrite which, in turn, induces protein tyrosine nitration, although other mechanisms such as oxidation of nitrites by myeloperoxidase can also induce similar protein alterations.12 Ruffoli et al.13 suggested that progressive epithelium injury in polyp tissues is caused by peroxynitrite. In addition to the toxic effect, this reaction might reduce the concentration of nitric oxide, thereby decreasing its bioavailability.14 The aim of this study was to investigate the role of malondialdehyde, superoxide dismutase and nitric oxide in nasal polyposis by comparing their concentrations in samples from nasal polyposis-affected and normal tissues. Patients and methods PATIENTS AND STUDY DESIGN This prospective, randomized, controlled study was designed and conducted from February 2007 to May 2008 at the Otolaryngology Head and Neck Surgery Department and the Biochemistry Department of Gulhane Military Medical Academy, Haydarpasa Training Hospital, Istanbul, Turkey. The study was approved by the Research Scientific Committee of Gulhane Military Medical Academy and informed written consent was obtained from all study participants. Male and female subjects were allocated into two groups, those with nasal polyposis (study group) and those without nasal polyposis who were healthy except for nasal septal deviation (control group). The Downloaded from imr.sagepu3b.c2om6by guest on October 16, 2014 diagnosis of nasal polyposis was based on anterior rhinoscopy, endoscopic endonasal examination and paranasal sinus computerized tomography scanning. Patients who had a history of nasal allergy, asthma, previous nasal surgery, acute infection, systemic disease, or aspirin sensitivity were excluded from either of the two groups. Nasal polyp tissue specimens were obtained from patients with nasal polyposis when they underwent endoscopic sinus surgery and were all reported as inflammatory polyps by the Pathology Department of Haydarpasa Train (...truncated)