Significance of Plasma Apoptosis Inhibitor of Macrophage Concentrations in Patients with Obstructive Sleep Apnea Syndrome: A New Biological Indicator of Severity and Treatment Responses

Abstract

Background: It has been reported that a 10% increase in s body weight predicts a 6-fold increase in the odds of developing moderate to severe obstructive sleep apnea syndrome (OSAS). Blood levels of apoptosis inhibitor of macrophage (AIM), produced by macrophages, increase with obesity progression. We aimed to investigate the association between plasma AIM levels and OSAS severity. We hypothesized that plasma AIM levels are influenced by OSAS severity. Methods: Plasma levels of AIM, monocyte chemotactic protein-1 (MCP-1), and ln high sensitivity-C-reactive protein were measured by ELISA in 97 male participants. Blood samples were obtained after overnight polysomnography (PSG) before and after nasal continuous positive airway pressure (nCPAP) treatment. Results: In 97 OSAS patients, their plasma AIM levels were positively correlated with the apnea hypopnea index (AHI) (r=0.353, p=0.0003) and oxygen desaturation of >3% events per hour (r=0.302, p=0.0025). Plasma AIM levels were significantly higher in patients with moderate to severe OSAS (AHI 15; 1,144.3 ± 342.5 ng/mL, mean + SD) than in mild OSAS (5 AHI 20, plasma AIM levels significantly decreased following nCPAP treatment (p<0.0001). Conclusion: The present study is the first to show that patients with OSAS have elevated plasma AIM levels, and that these levels are influenced by AHI but not by weight.