(554) Cervical mucin expression is associated with preterm birth: molecular determinants of mucus quality in pregnancy.

Cervical mucus serves as a key immune and structural barrier to prevent microbial ascension from the lower genital tract. Mucins are glycoproteins that contribute to the gel-like consistency of mucus and provide structural scaffolding. We previously showed that G. vaginalis, a vaginal anaerobe implicated in the pathophysiology of spontaneous preterm birth (sPTB), induces expression of select mucins and genes regulating mucus hydration in cervical epithelial cells in vitro. The impact of mucin profiles on pregnancy outcomes remains under investigated. We examined associations between cervical mucin expression and sPTB in human pregnancy.


Study Design:

This was a prospective, nested, case-control study of 23 sPTB cases and 23 term controls from the Boston-based Spontaneous Prematurity and Epigenetics of the Cervix (SPEC) study. Cases were matched on race, parity, and age. Gel-forming mucins (MUC2, MUC5AC, MUC5B, MUC6) and membrane-spanning mucins (MUC1, MUC16) were measured by ELISA from second trimester cervical swabs and normalized to total protein. T-tests were performed to compare groups.


Results:

Participant characteristics are presented in Table 1. Expression of MUC2 (2.94-fold), MUC5B (2.44-fold), MUC6 (1.85-fold), and MUC16 (3.52-fold) was higher in sPTB vs term controls (all p< 0.05, Fig. 1). Similar nonsignificant trends were seen for MUC5AC and MUC1. Total mucin content was 1.56-fold higher (p=0.006) and total membrane-spanning mucin content was 1.83-fold higher (p=0.004) in sPTB vs term. We did not detect a difference in total gel-forming mucin content across groups (p=0.24).  


Conclusion:

Higher concentrations of gel-forming and membrane-spanning cervical mucins are associated with sPTB. The hydrophilic properties of cervical mucins result in increased mucus water content, likely rendering mucus less viscous and more permeable to microorganisms. Modification of mucus properties in pregnancy may be targeted as a future therapeutic strategy to strengthen this biophysical barrier and mitigate microbiota-associated sPTB risk. Charles H. Hood Foundation (HHB). PennCHOP Microbiome Program (KDG).