Significance of Toll-like Receptor 4 Signaling in Peripheral Blood Monocytes of Pre-eclamptic Patients.

Objective: Preeclampsia (PE) is a serious condition affecting pregnant women and placing both the mother and fetus at risk. While little is known about the pathogenesis of PE, there is evidence for involvement from the maternal innate immune system, specifically, signaling arising from monocytes. The present study was to explore the role of Toll-like receptor (TLR) 4 on peripheral blood monocyte in the pathogenesis of PE.

Methods: This study included 22 patients with established preeclampsia and 23 healthy pregnant women (HP). All participants gave informed written consent for 4 mL of fresh venous blood to be collected into a tube containing heparin. The expression of TLR4 on monocytes was evaluated by flow cytometry (FCM). Monocytes were stimulated with LPS for 18 h and cytokine secretion (IL-6, IL-12P70, IL-10, and TNF-α) in supernatants was analyzed with Luminex platform (Luminex Corporation, Austin, TX). The expression of TLR4 and cytokine secretion (IL-6, IL-12P70, IL-10, and TNF-α) was compared between women with PE and healthy pregnant women.

Results: Compared with controls, the percentage of TLR4+ monocytes was significantly higher in PE patients. Collected monocytes stimulated with lipopolysaccharide (LPS) to induce inflammation had increased cytokine production, and monocytes from PE patients produced more IL-6 and TNF-α, and less IL-10 than cells from healthy participants. PE patients also showed a positive correlation between the percentage of TLR4+ monocytes and serum levels of IL-6 and TNFα.

Conclusions: These results suggest that TLR4 signaling may play a role in the pathogenesis of preeclampsia.