Elevated inflammatory mediators from the maternal-fetal interface to fetal circulation during labor

Area of Science:

• Reproductive biology
• Immunology
• Obstetrics

Background:

• Elevated cytokines, such as Interleukin-1 beta (IL-1β) and Interleukin-6 (IL-6), are implicated in labor pathogenesis.
• The transfer of inflammatory mediators from the maternal-fetal interface to fetal circulation during labor remains unclear.

Purpose of the Study:

• To investigate the changes in inflammatory cytokines, chemokines, and macrophages in the maternal-fetal interface and fetal circulation during labor versus non-labor states.
• To understand the maternal-fetal transfer of inflammatory mediators.

Main Methods:

• Samples of human myometrium, placenta, decidua, fetal membrane, and umbilical blood were collected from laboring and non-laboring women delivering at term.
• Luminex assays were used to quantify cytokine and chemokine levels (TNF-α, IL-1β, IL-6, IL-8, MCP-1, GM-CSF, MIP-1α, MIP-1β).
• Macrophage infiltration was assessed via immunohistochemistry.

Main Results:

• During labor, myometrium showed significantly higher levels of cytokines (TNF-α, IL-1β, IL-6, IL-8) and chemokines (MCP-1, MIP-1β), correlating with increased macrophage infiltration.
• Fetal membranes exhibited elevated IL-1β and IL-8 during labor.
• In fetal circulation, Interleukin-6 (IL-6) was significantly upregulated in umbilical vein blood during labor, with a trend for increased IL-8.

Conclusions:

• Labor is associated with significantly elevated inflammatory mediators in the maternal-fetal interface.
• These maternal inflammatory factors can transfer to fetal circulation, suggesting a role in labor onset.
• The observed inflammatory response and macrophage influx into pregnancy tissues highlight their potential importance in initiating labor.