Tandem Mass Tag-Labeled Quantitative Proteome Analyses Identify C1R and A2M as Novel Serum Biomarkers in Pregnant Women with Obstructive Sleep Apnea

The aim of this study was to identify serum diagnostic
biomarkers
associated with the severity of obstructive sleep apnea (OSA) during
pregnancy. Differentially expressed proteins (DEPs) were identified
in the control (C), mild (O), and moderate (MO) OSA groups (n = 3 in each group). Bioinformatics analysis was conducted
to identify the underlying functions, pathways, and networks of the
proteins. Receiver operating characteristic curves were used to assess
the diagnostic value of the identified DEPs. The enzyme-linked immunoassay
was performed to detect serum levels of the complement C1r subcomponent
(C1R) and alpha-2-macroglobulin (A2M) in 79 pregnant women with OSA
(mild OSA [n = 32]; moderate OSA [n = 29], and severe OSA [n = 18]) and 65 healthy
pregnant women without OSA. Pearson’s correlation analysis
was conducted to analyze the correlation between C1R and A2M levels
and OSA clinicopathological factors. In total, 141 DEPs, 29 DEPs,
and 103 DEPs were identified in the three groups (i.e., the mild OSA
vs control group, the moderate OSA vs mild apnea group, and the moderate
OSA vs control group, respectively). C1R and A2M were identified as
continuously up-regulated proteins, and the levels of C1R and A2M
were associated with OSA severity. C1R and A2M were found to be correlated
with body mass index, systolic blood pressure, apnea–hypopnea
index, oxygen desaturation index, time with saturation below 90%,
and lowest SaO2. Adverse maternal and neonatal outcomes
were observed in pregnant women with OSA. C1R and A2M have been identified
as diagnostic biomarkers and are associated with the severity of OSA
during pregnancy.