Purpose: Sleep architecture can be affected by alteration in circulating lipopolysaccaride and cytokines. However, still unknown are the effects of lipopolysaccaride-binding protein (LBP) on sleep architecture. Therefore, potential relationship between alteration in serum LBP concentrations and sleep architecture was analyzed.
Methods: This is a cross-sectional study. Consecutive 54 hypertensive males, aged 30-65 years. and with no obstructive sleep apnea via polysomnography, were recruited. Subjects were divided into two groups via the LBP median as hypertensives with higher and lower serum LBP (n = 27 and n = 27, respectively). Sleep architecture was assessed by polysomnography. Serum LBP, IL-1β, IL-6, and TNF-α were measured by commercial laboratories using sandwich-type enzyme immunoassay kit.
Results: Hypertensive subjects with higher LBP showed significantly higher inflammatory status as assessed by IL-1β (18.85 ± 3.71 vs 16.15 ± 4.00 ng/L, P = 0.009), IL-6 (67.64 ± 11.22 vs 58.94 ± 11.32 ng/L, P = 0.004), and TNF-α (322.27 ± 59.17 vs 283.89 ± 61.87 pg/ml, P = 0.024) than did those with lower LBP. Hypertensives with higher serum LBP also exhibited prolonged N1 % (7.63 ± 3.55 vs 4.98 ± 2.90 %, P = 0.002), the transition from wakefulness to other sleep stages or follows arousal during sleep, than did those with lower LBP. A significant positive correlation was observed between serum LBP concentrations and N1 % (r = 0.378, P = 0.005) via Spearman's correlation and remained significant even after adjusting for age, apnea-hypopnea index, and body mass index.
Conclusion: Elevation in serum concentrations of LBP might prolong N1 % in this middle-aged hypertensive males, which needs to be confirmed further.
Keywords: Hypertension; Inflammatory mediators; Males; Sleep stages.