Amniotic fluid HIF1α and exosomal HIF1α in cervical insufficiency patients with physical examination-indicated cerclage.

OBJECTIVE: Hypoxia inducible factor 1α (HIF1α) has been reported to activate inflammatory cascade. Recently, exosomes have been known to have pivotal roles in intercellular communication. The aim of this study was to compare the concentration of amniotic fluid (AF) HIF1α, exosomal HIF1α, and inflammatory cytokines such as interleukin 1α (IL1α), interleukin 1β (IL1β), interleukin 6 (IL6), and tumor necrosis factor α (TNFα) between physical examination-indicated cerclage (PEIC) and control group. We also investigated the associations between biomarkers and amniocentesis-to-delivery interval and the correlations of inflammatory cytokines, HIF1α, and exosomal HIF1α.

METHODS: Case-control study was performed. Cases are defined as 16 patients who underwent PEIC and controls are 19 women who underwent amniocentesis for confirming chromosomal abnormalities. The concentration of IL1α, IL1β, IL6, TNFα, HIF1α, and exosomal HIF1α were measured using enzyme-linked immunosorbent assay (ELISA). Exosomes were confirmed by tumor susceptibility Gene 101 (TSG 101) and transmission electron microscopy (TEM).

RESULTS: The mean HIF1α in PEIC group was higher than control group (PEIC, 15.03 ± 9.60-pg/mL versus control, 2.96 ± 1.99 pg/mL; p < .01). There were significant differences in inflammatory cytokines between two groups. A significant difference in exosomal HIF1α was shown between two groups (PEIC, 27.97 ± 28.61-µg/mL versus control, 12.42 ± 8.20 µg/mL; p < .01). HIF1α, IL1α, IL6, TNFα, and exosomal HIF1α showed significantly negative association with cerclage-to-delivery interval. However, IL1β was not associated with cerclage-to-delivery interval. HIF1α was positively correlated with exosomal HIF1α (rho = 0.93, p < .01). Both HIF1α and exosomal HIF1α were significantly associated with TNFα (rho = 0.94, p < .01; rho = 0.97, p < .01). Both HIF-1α and exosomal HIF1α had positive correlation with IL1α (rho = 0.96, p < .01; rho = 0.91, p < .01). However, IL1β showed no correlations with HIF1α and exosomal HIF1α. A positive correlation between HIF-1α and IL6 was observed (rho = 0.58, p = .01.) Exosomal HIF1α also had correlation with IL6 (rho = 0.52, p = .03).

CONCLUSIONS: This study demonstrated that amniotic fluid (AF) HIF1α and AF exosomal HIF1α were higher in physical examination-indicated cerclage (PEIC) group than control group. AF HIF1α and AF exosomal HIF1α were associated with shorter amniocentesis-to-delivery interval. More importantly, they had positive correlations with AF inflammatory cytokines such as IL1α, IL6, and TNFα. Our results may indicate that AF HIF1α and AF exosomes interact with AF inflammatory cytokines and contribute inflammatory cascade in complicated pregnancies.