Decreased ALCAM expression and promoter hypermethylation is associated with preeclampsia

Preeclampsia (PE) is a major obstetrical complication that results in maternal and fetal morbidity and mortality. Aberrant epigenetic modifications are widely involved in the pathogenesis of PE. Previously, the activated leukocyte cell adhesion molecule (ALCAM) was reported to be required for blastocyst implantation but has not been described in the context of pathological pregnancy. This study explored the expression of ALCAM and its methylation levels in the placentas and peripheral venous blood of patients with PE from a Chinese Han population. The mRNA and protein expression levels of ALCAM were downregulated in the PE placentas compared with the control placentas (P < 0.05). The methylation rate of the ALCAM gene promoter was considerably elevated in the placentas (P = 0.003, odds ratio (OR) = 0.264, 95% confidence interval (95% CI) [0.108-0.647], cases n = 47, controls n = 53) and peripheral blood (P = 0.007, OR = 0.455, 95% CI [0.256-0.806], cases n = 100, controls n = 100) of the PE patients compared with those of the normotensive women, suggesting a negative relationship between ALCAM methylation and gene transcription. Moreover, the transcriptional expression of ALCAM was dramatically increased by demethylating treatment in trophoblastic cells. ALCAM is expected to be involved in the pathogenesis of PE through methylation regulation.