Morning pentraxin3 levels reflect obstructive sleep apnea-related acute inflammation

This study investigated morning levels of pentraxin3 (PTX3) as a sensitive biomarker for acute inflammation in patients with obstructive sleep apnea (OSA). A total of 61 consecutive patients with OSA were divided into two groups: non-to-mild (n = 20) and moderate-to-severe (n = 41) OSA based on their apnea-hypopnea index (AHI) score. Those patients with moderate-to-severe OSA were further divided into continuous positive airway pressure (CPAP) treated (n = 21) and non-CPAP-treated (n = 20) groups. Morning and evening serum PTX3 and high-sensitivity (hs) C-reactive protein (CRP) levels were measured before and after 3 mo of CPAP therapy. The baseline hs-CRP and PTX3 levels were higher in patients with moderate-to-severe OSA than in those with non-to-mild OSA. Moreover, the serum PTX3 levels, but not the hs-CRP levels, were significantly higher after than before sleep in the moderate-to-severe OSA group (morning PTX3, 1.96 ± 0.52; evening PTX3, 1.71 ± 0.44 ng/ml). OSA severity as judged using the AHI was significantly correlated with serum PTX3 levels but not hs-CRP levels. The highest level of correlation was found between the AHI and morning PTX3 levels (r = 0.563, P < 0.001). CPAP therapy reduced evening and morning serum hs-CRP and PTX3 levels in patients with moderate-to-severe OSA; however, the reduction in PTX3 levels in the morning was greater than that in the evening (morning -29.8 ± 16.7% vs. evening -12.6 ± 26.8%, P = 0.029). Improvement in the AHI score following CPAP therapy was strongly correlated with reduced morning PTX3 levels(r = 0.727, P < 0.001). Based on these results, morning PTX3 levels reflect OSA-related acute inflammation and are a useful marker for improvement in OSA following CPAP therapy.