Determination And Analysis Of Adipocyte-Fatty Acid Binding Protein In Serum Of Patients With Obstructive Sleep Apnea Syndrome

OBJECTIVE:Adipocyte-fatty acid binding protein (A-FABP) traditionally thought to be a cytoplasmic protein in adipocytes and belongs to the fatty acid-binding protein superfamily.It widely exists in normal tissue cells and released from adipocytes into the bloodstream. A-FABP may play an important role in lipid and glucose metabolism and also inflammation. In recent years, some clinical and animal experiments have showed that A-FABP had significant correlation with obstructive sleep apnea syndrome(OSAS). Our purpose was to investigate the relationship between OSAS and A-FABP.METHODS:From January 2009 to February 2010, twenty-five patients with OSAS(male, aged 43.12±9.84years) were recruited as the study group. All patients were diagnoseded by overnight polysomnography(PSG)at the sleep laboratory of the Second Hospital of Shandong University. The control group included fifteen non-OSAS cases(male, aged 43.87±12.83years). The ages between the two groups had no significant difference. Their heights as well as weights were measured and the BMI were calculated. The exclusion criteria were as follows:known history of hypertension or diabetes mellitus, hyperlipidaemia on lipid-lowering therapy, cardiovascular diseases or other major chronic medical illness. Serum A-FABP levels were checked by enzyme-linked immunosorbent assays. RESULTS:Serum A-FABP levels of OSAS patients were significant higher than the controls'(35.68±10.11 vs 18.61±7.26ng/ml,t=5.75,P<0.05).Serum A-FABP concentrations showed positive correlation with apnea-hypopnea index (AHI), total time of hypopnea and apnea, total number of apnea, oxygen reduction index; negative correlation with minimal oxygen saturation, no correlations with the longest apnea time. When the OSAS patients were divided into three subgroups according to AHI,we found that the concentrations of A-FABP increased with the increasing of AHI:mild (5≤AHI<20, A-FABP 25.7±94.90ng/ml), moderate (2040, A-FABP 44.41±9.92 ng/ml).CONCLUSIONS:The adipocyte-fatty acid binding protein levels in patients with obstructive sleep apnea syndrome were higher than in normal controls and had a interdependency with the severity of OSAS.