Complement protein levels in serum astrocyte-derived exosomes are associated with cognitive impairment in obstructive sleep apnea

Complement proteins were implicated in cognitive impairment in patients with OSA and may be promising biomarkers for predicting cognitive impairment in patients with OSA. Clinical

All participants with subjective snoring complaints from the Sleep Medicine Center underwent polysomnography. OSA was defined as apnea-hypopnea index ≥ 5 events/h. MCI was defined as the Montreal Cognitive Assessment < 26 and met the criteria: (1) a subjective cognitive impairment; (2) an objective impairment in 1 or more cognitive domains; (3) complex instrumental daily abilities can be slightly impaired but independent daily living abilities are maintained; and (4) no dementia. The ADEs were isolated immunochemically for enzyme-linked immunosorbent assay quantification of complement proteins, including C3b, C5b-9, and CD55. The participants who received continuous positive airway pressure were followed up and their complement protein levels were reassessed after 1 year of treatment.

A total of 212 participants (66.98% males; mean age of 56.71 ± 10.10 years) were divided into the OSA+MCI group (n = 90), OSA-MCI group (n = 79), and controls (normal cognitive state without OSA) (n = 43). The ADE levels of C3b and C5b-9 in the OSA+MCI group were higher than those in the OSA-MCI and control groups. The C3b and C5b-9 were independently associated with cognitive impairment in patients with OSA. The relationship between apnea-hypopnea index and Montreal Cognitive Assessment scores was mediated by C3b and C5b-9. We found no linear correlation between the complement proteins and the severity of OSA. The complement proteins were negatively correlated with global cognitive performance and cognitive subdomains. The complement protein levels significantly decreased after continuous positive airway pressure treatment. Conclusions: Complement proteins were implicated in cognitive impairment in patients with OSA and may be promising biomarkers for predicting cognitive impairment in patients with OSA. Clinical

Registry: Chinese Clinical Trial Registry; Name: Study on early diagnostic markers in patients with dementia and mild cognitive impairment; URL: https://www.chictr.org.cn/; Identifier: ChiCTR1900021544. Citation: Li M, Sun C, Xue S, et al. Complement proteins levels in serum astrocyte-derived exosomes are associated with cognitive impairment in obstructive sleep apnea. J Clin Sleep Med. 2023;19(4):727-739.