Glymphatic imaging and serum glial biomarkers in children with obstructive sleep apnea.

OBJECTIVES

The glymphatic system, which is most active during sleep, may be disrupted in obstructive sleep apnea (OSA). We evaluated glymphatic function in children with OSA using diffusion tensor imaging-along the perivascular space (DTI-ALPS) index together with serum glial fibrillary acidic protein (GFAP) and S100 calcium-binding protein B (S100B) levels.

METHODS

Obese children scheduled for overnight polysomnography (PSG) were enrolled and classified as having OSA or not, based on PSG findings. Age- and sex-matched healthy non-obese children served as controls, with those showing Epworth Sleepiness Scale scores suggestive of OSA excluded. All participants underwent brain magnetic resonance imaging (MRI) for DTI-ALPS index calculation and blood sampling for GFAP and S100B measurement.

RESULTS

Eighty-four children were included: 31 with obesity + OSA, 35 with obesity + non-OSA, and 18 healthy controls. The groups were comparable in age and sex, while body mass index differed significantly. The median value of DTI-ALPS index was lowest in obese + OSA compared with obese + non-OSA and healthy groups (1.50, 1.66, 2.00, respectively; p = 0.030). Following adjustment for age and sex, post-hoc analyses demonstrated significantly lower DTI-ALPS index in the obese + OSA group compared to healthy controls (p = 0.021). Serum GFAP levels were significantly higher in obese + OSA group (p = 0.004), however S100B did not differ significantly between groups (p = 0.101).

CONCLUSION

Our results suggest impaired glymphatic function in obese children with OSA, reflected by reduced DTI-ALPS index and elevated serum GFAP levels, independent of age and sex. Larger longitudinal studies are required to confirm causality.