Matrix metalloproteinase-9 gene -1562C/T polymorphism mitigates preeclampsia.

Although the aetiology of preeclampsia is unknown, there is substantial evidence that it finds its roots in abnormal placentation. Prerequisites for successful placentation include trophoblast invasion, degradation and remodelling of the uterine decidual extracellular matrix, and apoptosis without thrombosis. We tested this hypothesis by analysing the effect of functional polymorphisms in the genes coding for MMP9, MMP3 and annexin A5 on the risk of preeclampsia using a case-control design. In 163 women with preeclampsia and 163 controls we studied the association with polymorphisms in the MMP9 (-1562 C/T), MMP3 (-1612 5A/6A) and annexin A5 (-1 C/T) genes using logistic regression analysis. A lower prevalence of the rare T allele of the MMP9 (-1562 C/T) polymorphism in women with preeclampsia was found (odds ratio 0.48, 95% confidence interval 0.25-0.90). The distribution of the MMP3 (-1612 5A/6A) and annexin A5 (-1 C/T) gene polymorphisms were similar in cases and controls. Our results suggest that the MMP9-1562T allele is associated with a reduced risk of preeclampsia and therefore may protect against maladaptation of the spiral arteries and decreased decidual degradation. The elevated MMP9 concentrations reported to be associated with the -1562T allele might be essential for the development of an adequate maternal-fetal interface early in pregnancy by facilitating trophoblast apoptosis and degradation.