The relationship of serum angiotensin converting enzyme (ACE) level with the severity of obstructive sleep apnea syndrome (OSAS)

Obstructive sleep apnea syndrome (OSAS) is a sleep disorder characterized by repetitive upper airway obstructions, hypoxia, reoxygenation, and arousals, in which there is no airflow in the mouth and nose despite respiratory effort during sleep. Free oxygen radicals formed in this repetitive process lead to an increase in cardiovascular and metabolic morbidity due to vascular endothelial dysfunction. Angiotensin converting enzyme (ACE); It is a zinc dependent dicarboxypeptidase. This enzyme is produced mainly in the lung and is found in the luminal portion of the endothelial cells of the pulmonary vessels. While catalyzing the conversion of Angiotensin 1 to Angiotensin 2, it plays a role in inactivating bradykinin and substance P, which are bronchoconstrictors and inflammatory mediators. ACE enzyme activity may change in pulmonary diseases accompanied by vascular endothelial damage. There is very little data from the Turkish population showing the relationship between the severity of obstructive sleep apnea syndrome (OSAS), apnea-hypopnea index (AHI), apnea time, and serum Angiotensin converting enzyme (ACE). The aim of our study is to determine the relationship between Obstructive sleep apnea syndrome (OSAS) and serum Angiotensin converting enzyme (ACE) with the data we obtained from the appropriate patient group using scientific methods. It is a prospective and cross-sectional study. A total of 90 people participated voluntarily. According to the volunteer PSG results, the patient group with OSAS was divided into the control group without OSAS. Volunteers consisted of patients who applied to Tekirdağ Namık Kemal University Medical Faculty Hospital Chest Diseases Polyclinic with the suspicion of OSAS or who were suspected of OSAS from an external center for polysomnography (PSG) examination. PSG test was performed by inpatient overnight in the Sleep Disorder Unit. Before the test, gender, height, weight, BMI, smoking habit, history of chronic disease, contact information, and identity information were noted. The next morning after PSG, blood was taken from the patients for serum ACE, hemogram and biochemistry from venous blood.The mean serum ACE value of men in the OSAS group was 33.56±16.62 IU/L, the mean serum ACE value of women was 32.27±17.61 IU/L, the mean serum ACE value of the whole group was 32.92±16.98 IU/L calculated. The mean serum ACE value of men in the control group was 35.69±20.33 IU/L, the serum ACE value of women was 9.14±10.37 IU/L, and the serum ACE value of the whole group was 32.42±16.21 IU/L. In the group with OSAS, according to PSG results, it was severe in 34 (56.6%), moderate in 23 (38.3%), and 3 (5.1%) individuals. According to the severity of OSAS, mean serum ACE values were calculated as 35.14±18.93 IU/L for severe OSAS, 30.24±13.72 IU/L for moderate OSAS, 28.3±18 IU/L for mild OSAS. As the severity of OSAS increased, an increase in serum ACE value was observed, and there was no statistically significant difference. Serum ACE values in OSAS and control groups and serum ACE values between genders were compared and no statistically significant difference was observed. When the correlation between AHI and serum ACE values was made, no statistically significant difference was observed. Keywords: Angiotensin converting enzyme, Hypoxia, Obstructive sleep apnea syndrome, PSG test