Abstract
OBJECTIVE: Previously, we demonstrated that live Chlamydia pneumoniae (Cp) impaired extravillous trophoblast (EVT) viability and invasion and that Cp DNA was detected in placentas from cases with preeclampsia. We sought to elucidate whether (1) inactive forms of Cp also affect EVT function; (2) potential therapeutic interventions protect against the effects of Cp; and (3) anti-Cp antibodies are associated with preeclampsia. METHODS: Human first-trimester EVTs were infected with ultraviolet light-inactivated Cp. Subgroups of EVTs were pretreated with low-dose acetyl-salicylic acid (ASA), dexamethasone, heparin, and indomethacin. We conducted functional assays after infection with inactivated Cp and measured interleukin 8 (IL8), C-reactive protein (CRP), heat shock protein 60 (HSP60), and tumor necrosis factor-α (TNFα) in culture media. We measured anti-Cp IgG serum levels from women who developed preeclampsia (N = 105) and controls (N = 121). RESULTS: Inactivated Cp reduced EVT invasion when compared to noninfected cells (P < .00001) without adversely affecting cell viability. Increased levels of IL8, CRP, HSP60, and TNFα were detected in EVTs infected with inactivated Cp compared to noninfected cells (P < .0001). Only pretreatment with low-dose ASA prevented reduced EVT invasion and decreased release of inflammatory mediators (P < .01). Elevated anti-Cp IgG antibodies were more prevalent in serum from cases with preeclampsia compared to controls (67/105 vs 53/121; adjusted P = .013); elevated IgG correlated significantly with elevated serum CRP and elevated soluble fms-like tyrosine kinase-1-placental growth factor ratio. CONCLUSION: Inactivated Cp induces decreased EVT invasion and a proinflammatory response; these effects were abrogated by pretreatment with low-dose ASA. Our results suggest an association between Cp infection, trophoblast dysfunction, and preeclampsia.