Immunohistochemical localization of heme oxygenase-1 and bilirubin/biopyrrin of heme metabolites as antioxidants in human placenta with preeclampsia.

Introduction: We performed an immunohistochemical investigation of the localization of Heme oxygenase(HO-1) and bilirubin(BR)/biopyrrin(BPn) to elucidate whether a response to oxidative stress is generated in the human placenta. Methods: Placentas from nine patients with preeclampsia(PE) and seven controls were investigated. Results: For HO-1 and BR/BPn expressions, a higher number of positive cells were observed in the PE group than in the control group. Conclusions: The degree of these expressions tended to relate to the onset of PE. This suggests that the heme catabolic pathway induced by oxidative stress plays an important role in the pathophysiology of PE.