Elevated placental estradiol: A possible etiological factor of human cryptorchidism

Purpose: It has been convincingly argued that the increasing incidence of reproductive abnormalities in human males may be associated with increased estrogen exposure during gestation. We documented the expression of estradiol in the syncytiotrophoblast and placenta of males born with cryptorchidism and normal genitalia, respectively. Materials and Methods: Tissue from newborn placentas was fixed in glutaraldehyde and embedded in ePON for immunohistological procedures. Cryptorchidism was unilateral in 6 males and bilateral in 1. Semithin histological sections of placental biopsies of these 7 males and 7 randomly selected, normal male placentas were analyzed immunohistochemically with a polyclonal anti-estradiol-17 beta, 6-keto antibody. Results: The weak expression of estradiol in the placentas of normal males was localized predominantly at the basal part of the syncytiotrophoblast in the terminal placental villi. In contrast, all placentas of cryptorchid males had strong expression of estradiol at the basal portion of the syncytiotrophoblast. Conclusions: The increased expression of estradiol in the syncytiotrophoblast may have an impact on testicular descent.