Effect of positive airway pressure therapy on asymmetric dimethyl arginine (ADMA) level in obstructive sleep apnea

Recurrent hypoxia/hypoxemia and reoxygenation occurring in patients diagnosed with Obstructive Sleep Apnea Syndrome (OSA) can activate oxidative stress systems. Oxidative stress affects serum ADMA levels by making changes in the activities of catalysts involved in the production of asymmetric dimethyl arginine (ADMA). Asymmetric dimethyl arginine (ADMA) is a methylated arginine derivative formed as a result of the post-synthesis addition of methyl groups to arginine residues in nucleoproteins by the protein arginine methyl transferase enzyme and the degradation of proteins. The aim of our study is to determine the relationship between serum ADMA level and OSA and to investigate the effect of positive airway pressure therapy. Patients who were recorded for polysomnography at Bozok University Faculty of Medicine Sleep Disorders Center were included in the study. Permission was received for the study protocol from Yozgat Bozok University Ethics Committee. The patients' age, gender, habits, comorbid diseases, height, weight, body mass index (BMI), neck circumference, waist circumference, and PSG parameters were recorded in the created study form. They were randomly selected so that no significant difference (p>0.05) was detected between the patient and control groups in terms of age, gender, body mass index and symptom frequency. OSA cases with an AHI value above 5 were included in the study. The control group was selected from simple snoring cases with AHI<5. Blood samples were taken on an empty stomach in the morning following PSG. Blood samples taken from peripheral veins in the patient and control groups were centrifuged at 3000 rpm for 10 minutes, and then the separated sera were stored at -20°C until they were to be studied. Patients who were diagnosed with OSA and planned to use PAP therapy were called the treatment group, and blood was taken in the morning from patients who used adequate PAP therapy for 1 month, following a 1-night fast, and after centrifugation, they were placed in a -20 degree freezer. ADMA levels were measured from the patients' blood taken on the morning of the test using the ADMA direct ELISA kit (immunodiagnostic AG) enzyme-linked competitive immune measurement method. PAP treatment reduced serum asymmetric dimethyl arginine levels in patients diagnosed with OSA. Thus, PAP treatment helped reduce systemic oxidative stress in serum.