Evaluation of nitrosative stress in polyp tissue in patients undergoing functional endoscopic sinus surgery due to nasal polyposis

INTRODUCTION: Nasal polyposis is a recurring condition affecting approximately 10% of the adult population, significantly impacting respiratory health and quality of life. Despite various treatment options such as steroid use and surgical approaches, recurrence rates remain high. Nasal polyps, typically benign growths, commonly originate from the ethmoid sinuses and present with symptoms such as nasal congestion, loss of smell, facial pain, and mucopurulent discharge. Diagnosis is typically made through endoscopic examination and paranasal CT scans. The etiology of nasal polyps remains insufficiently understood. Nitrosative stress, characterized by the emergence of a range of reactive nitrogen species molecules such as peroxynitrite and nitric oxide, has been implicated in numerous chronic conditions like ischemic heart disease and chronic progressive lung disease. These molecules affect matrix metalloproteinases, creating a stressful microenvironment that disrupts the extracellular matrix, leading to excessive accumulation of mediators causing inflammation. While nitric oxide (NO) has beneficial physiological effects, its overproduction leads to cytotoxic events in the body, contributing to nitrosative stress (NS). The primary aim of this study is to investigate the relationship between nasal polyps and the levels of eNOS, iNOS, and 5-NT, defined as NS markers. MATERIALS and METHODS: In this study, nasal polyp tissue samples from 30 patients undergoing endoscopic sinus surgery and nasal mucosa samples from 30 patients without nasal polyps who underwent only inferior turbinate and septum interventions will be collected. These samples will serve as the control group, and nitrosative stress end products will be evaluated. Following detailed medical history and physical examination, biochemical, complete blood count, and endoscopic evaluations were routinely performed and recorded. Tissue samples were stored at -80 degrees Celsius and analyzed in the Biochemistry Center laboratory at Harran University Faculty XIV of Medicine. The collected data were analyzed using SPSS 27. Descriptive statistical methods such as mean, standard deviation, median, minimum, and maximum values were used for quantitative variables, while qualitative variables were presented using frequency and percentage. Normality and correlation were assessed using the Shapiro-Wilk test and Box Plot graphs. For variables not showing normal distribution, the Mann-Whitney U test was used for comparisons between two groups, the Kruskal-Wallis test for comparisons among three groups and above, and the Dunn test for identifying the group causing the difference. The comparison of qualitative data was performed using the Chi-square test. Results were evaluated with a 95% confidence interval, considering significance at p <0.05. RESULTS: Our study included 30 patients in the patient group and 28 in the control group. Two individuals were excluded due to insufficient material. The patient group comprised 19 males and 11 females, while the control group had 15 males and 13 females, with no statistically significant difference in gender distribution (p=0.451). The mean age of the patient group was 34 (18-59), significantly higher than the control group's mean age of 25 (18-45) (p=0.004, p<0.05). Statistically significant differences were observed between groups in terms of eNOS (IU/ml) levels (p=0.001, p<0.01). Specifically, eNOS levels in patients with nasal polyps were higher than those in the inferior turbinate mucosa and control groups (p=0.001, p<0.01). Similarly, significant differences were found in 3-NT (NG/ml) levels among groups (p=0.001, p<0.01), with higher levels in patients with nasal polyps compared to those in the inferior turbinate mucosa and control groups (p<0.01). No statistically significant difference was observed in iNOS2 (PG/ml) levels among groups (p>0.05). CONCLUSION: Nitrosative stress, particularly associated with the excessive production of nitrogen-based free radicals, is a significant factor. Our study demonstrates elevated nitrosative stress parameters in nasal polyp tissue, suggesting its potential importance in the etiology of nasal polyposis and its role in more effective treatment and reducing recurrence. Further studies on nitrosative stress parameters in larger cohorts are expected to contribute to treatment modalities significantly. Keywords: Nasal polyp, nitrosative stress, free radical, inflammation, NO, iNOS, eNOS