Interaction between methylated arginine metabolites and oxidative stress in periodontitis: a cross-sectional study

Abstract

Objectives Periodontitis is a chronic inflammatory disease associated with systemic conditions such as endothelial dysfunction. Nitric oxide (NO) plays a central role in inflammation and oxidative stress, both of which are critical in periodontal pathogenesis. Arginine (Arg) is the precursor of NO, while its methylated derivatives, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA), inhibit NO synthesis. This study investigated the interplay between NO metabolism and oxidative stress in periodontitis. Materials and methods A cross-sectional study was conducted with 20 patients with periodontitis and 20 healthy controls. Clinical periodontal assessments were performed, and salivary and serum levels of the oxidative stress index (OSI), ADMA, SDMA, and arginine were measured using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Statistical significance was set at p < 0.05. Results Groups did not differ by age or sex (p = 0.053 and p = 0.507). Clinical periodontal parameters were significantly higher in the periodontitis group (p < 0.001). Salivary OSI, ADMA, SDMA, and Arg were significantly elevated in periodontitis patients (p = 0.026, p = 0.002, p = 0.006, and p < 0.001), while serum SDMA levels were reduced (p = 0.026). Salivary OSI, ADMA, and Arg correlated positively with all clinical periodontal parameters (p < 0.05). Salivary SDMA correlated with probing depth (r = 0.329, p = 0.039), and strong associations were observed between salivary ADMA and SDMA (r = 0.722, p < 0.001) and between serum ADMA and Arg (r = 0.461, p = 0.003). Conclusion This study underscores the complex interplay between NO metabolism, oxidative stress, and inflammation in periodontitis, suggesting that ADMA- and SDMA-mediated disruption of Arg metabolism may exacerbate oxidative stress and inflammation, worsening the disease.