Recently, increasing interest has been given to HO-1 in preeclampsia by mainly studying the placental tissue [12–15], and interestingly, George et al. [16] demonstrated that the induction of HO-1 attenuates placental ischemia-induced hypertension in a rat model of preeclampsia, whereas inhibition of HO-1 activity increases the mean blood pressure [17]. This evidence concerns the gene HMOX1 and preeclampsia.