Clinical trial Assessment of the serum paraoxonase activity and oxidant/ antioxidant status in patients with recurrent aphthous stomatitis Serap Gunes Bilgili 1 , MD, Halil Ozkol 2 , ???? 1 , Zennure Takci 4 , MD, Hatice Uce Ozkol 5 , MD, Ayse Serap Karadag 1 , MD, and Mehmet Aslan 3 , MD Departments of 1 Dermatology 2 Medical Biology 3 Internal Medicine, Faculty of Medicine, Yuzuncu Yil University, Van, 4 Department of Dermatology, Kecioren Educational and Research Hospital,Ankara, and 5 Department of Dermatology, Van Research and Training Hospital, Van, Turkey Correspondence Serap Gunes Bilgili, MD Department of Dermatology School of Medicine Yuzuncu Yil University 65000 Van Turkey E-mail: drserapgunes@yahoo.com Conflicts of interest : Xxxx 4 doi: 10.1111/ijd.12084 Abstract Objectives Several studies have indicated that recurrent aphthous stomatitis (RAS) is associated with oxidative stress. The aim of this study was to investigate serum paraoxonase (PON1) 2 activity and oxidant/antioxidant status in patients with RAS. Design and methods Thirty-one patients with RAS and 31 healthy controls were enrolled. Serum PON1 3 and arylesterase activities, total antioxidant capacity, total oxidant status, and oxidative stress index were determined. Results Serum total antioxidant capacity levels, PON1, and arylesterase activities were significantly lower in RAS than controls (P< 0.001), while total oxidant status levels and oxidative stress index were significantly higher (P< 0.001). PON1 activity had a significant correlation with high-density lipoprotein cholesterol only (r = 0.482, P< 0.05), while there were no correlations with other lipids (P > 0.05) in patients with RAS. Conclusions Our results indicate that RAS is associated with decreased PON1 activity and increased oxidative stress that plays a crucial role in the pathogenesis of RAS. Further studies on a larger number of patients are needed to verify these results. Introduction 5 Recurrent aphthous stomatitis (RAS) is one of the most common oral mucosal disorders and is characterized by clinical symptoms that include recurrent and painful oral aphthae. 1 The prevalence of RAS ranges from 25 to 35% in the general population. 2,3 Although the etiology is uncertain, the following have been implicated: genetic, immunologic, viral or bacterial infectious factors; smok- ing; vitamin deficiency; iron deficiency; hormonal status; drug allergies; and nutritional factors. 4–6 Moreover, RAS has been shown to be associated with a variety of under- lying systemic diseases, including chronic inflammatory bowel diseases, gluten enteropathy, agranulocytosis, and cyclical neutropenia. 7 Oxidative stress is defined as a process in which the dynamic redox balance between oxidants and antioxi- dants is intensely shifted toward oxidative potentials. 8 The human organism has a complex defense system that protects against the activity of reactive oxygen species (ROS); this system is referred to as the antioxidative sys- tem. Oxidative stress constitutes the basis for many dis- eases, and may account for the severity of systemic and oral disease complications. 9 It has been indicated that decreased antioxidant system activities and increased ROS production may play a role in the pathogenesis of RAS. 10 Recently, Gurel et al. 11 reported that aphthae for- mation is associated with a final common pathway based on increased oxidative stress. Paraoxonase 1 (PON1) is a 354 amino acid (45 kDa) Ca 2+ -dependent serum esterase that is synthesized in the liver. 12 PON1 is a high-density lipoprotein (HDL) -associated antioxidant enzyme in the blood that has paraoxonase, arylesterase, and dyazoxonase activities. 13 PON1 is capable of hydrolyzing accumulated lipid perox- ides. In addition, human serum PON1 contributes to the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 ª 2012 The International Society of Dermatology International Journal of Dermatology 2012 1 I J D 1 2 0 8 4 B Dispatch: 15.12.12 Journal: IJD CE: GeethaPriya P. Journal Name Manuscript No. Author Received: No. of pages: 6 PE: Durga