Analysis of plasma exosomal differential proteins and bioinformatics in intrahepatic cholestasis of pregnancy

Introduction: Intrahepatic cholestasis of pregnancy (ICP) is a gestational liver disorder characterized by maternal pruritus and elevated serum bile acids, which is associated with an increased risk of adverse fetal outcomes. The identification of stage-specific diagnostic markers of ICP is crucial for timely diagnosis and stratified intervention. Methods: This study aimed to identify differentially expressed proteins (DEPs) from patients with ICP at different stages of severity using sequential window acquisition of all theoretical fragment ions (SWATH) proteomics, and to provide preliminary insights into the underlying pathology of the disease. We performed quantitative proteomic profiling of both total exosomes and placenta-derived exosomes isolated from the plasma samples of 35 pregnant women, including 10 with moderate ICP, 10 with severe ICP and 15 healthy controls. Results: SWATH proteomics identified 109 and 46 DEPs in the ICP/CTR comparison for of total exosomes (T-EXO) and placenta-derived exosomes (P-EXO), respectively. Bioinformatics analysis revealed that these proteins are involved in complement activation, blood coagulation and stress responses in pregnant women with ICP. Through the screening of hub proteins, we identified HRG, VWF and PIGR as three key proteins, which were verified by Western blotting. Discussion: We hypothesize that elevated maternal total bile acids (TBA) may induce a fetal stress response, leading to the release of procoagulant factors into the maternal bloodstream. Furthermore, PIGR was consistently upregulated in both plasma and placental exosomes, suggesting its potential involvement in the pathogenesis of ICP.