KLK4 and preeclampsia: Alterations in pregnancy in Brown Norway rats [46], a strain with a defective kallikrein-kinin system [47], and the high predictive index of preeclampsia of low urinary kallikrein in early human pregnancy [48], suggest that a deficient kallikrein-kinin system may hinder the local adaptations of pregnancy, thus its functional role deserves to be elucidated.