Evaluation of the PAPP-A levels in OSAS patients and relationship between its severity

Introduction: Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent episodes of upper airway obstruction during sleep with associated intermittent hypoxia. OSAS is an increased risk for cardiovascular and cerebrovascular conditions and events. Although pathogenesis of OSAS is debated, inflammation has been indicated as a potential mechanism. And also, OSAS has indeed been associated with elevated levels of various circulating inflammatory markers. Pregnancy associated plasma protein-A (PAPP-A) is one of zinc-binding metalloproteinase that has an important role in inflammatory processes. It has been studied in many inflammatory and immunological diseases in recent years. In our knowledge there are no published studies on the relationship between OSAS and serum PAPP-A levels. In this study, we aimed to investigate serum PAPP-A levels in patients with OSAS and the relationship between PAPP-A levels and severity of OSAS, apnea-hypopnea index (AHI), O2 levels, sleep stages and body mass index (BMI). Material method: 44 patients with OSAS and 44 healthy adults were included in this study. The exclusion criteria's were rheumatic or systemic inflammatory disease, advanced liver or kidney failure, diabetes, heart failure, known hypertension, pregnancy, prerenal azotemia, known history of coronary artery disease (CAD), history of major trauma or surgery with in six 6 months, inhaled nasal or systemic corticosteroid use or other anti-inflammatory medications, asthma, COPD, rhinitis, or atopy and those with <18 years of age. In addition of the routine tests of the patients, serum PAPP-A levels were determined by Elisa method with the immune sandwich measuring method. Statistical analysis of the study was performed with SPSS 17.0 statistical analysis package program and p<0.05 was considered as significant. Results: In this study, serum PAPP-A levels of patients with OSAS (2.350 ng/ml (0.641-4.796)) was significantly higher (p<0.001) when compared with healthy controls (0.971 ng/ml (0.109-2.679)). There were statistically significant difference in serum PAPP-A levels between groups of OSAS patients according to the classification of OSAS severity. Between the groups of patients with OSAS, serum levels of PAPP-A in moderate group was significantly higher when compared with severe OSAS group (p<0.001). There was positive correlation between PAPP-A levels and night minimum (p= 0.042, r=0.309), and average oxygen levels (p= 0.006, r=0.407), and a negative correlation between PAPP-A levels and AHI (p=0.002, r=-0.460). Conclusion: Serum PAPP-A levels were significantly higher in patients with OSAS when compared with healthy controls. According to the classification of OSAS severity, serum levels of PAPP-A in moderate group was significantly higher than severe group. Due to the our study was the first investigation that evaluating serum PAPP-A levels of the patients with OSAS in the literature, large prospective studies are required to better elucidate the role played by PAPP-A in disease processes. Keywords: OSAS, serum PAPP-A levels, OSAS severity