Role of cytokines in altitude-associated preeclampsia

BackgroundPreeclampsia (PE) is more common at high than low altitude and contributes to the altitude-related decline in birth weight. Since inflammatory markers are implicated in PE, we asked if such markers differed in PE vs. normotensive pregnant (NORM) women residing at high altitudes (3600–4100 m), and were related to uterine artery blood flow (UA BF) or fetal growth.MethodsSubjects were 33 Andean pregnant residents of Bolivia, comprising six with early-onset PE (⩽34 wks), 12 with late-onset PE (>34 wks), and 15 gestational-age-matched NORM. Maternal pro- and anti-inflammatory cytokines were measured using a multiplex bead-based assay and UA BF by Doppler ultrasound.ResultsPE compared to NORM women had higher levels of the pro-inflammatory cytokines IL-6 and IL-8 as well as higher levels of the anti-inflammatory cytokine IL-1ra, but only IL-6 levels were higher when gestational age was controlled. Women with early- vs. late-onset PE had higher TNFα levels, and higher IL-6 was negatively correlated with birth weight in all women at ⩽34 wks. We suggest that pro-inflammatory factors influence both the timing and severity of PE at high altitude.