Association of placental thyroid hormone concentrations with congenital cryptorchidism

Zhong-Min Li; David Hernandez-Moreno; Katharina Maria Main; Niels Erik Skakkebaek; Hannu Kiviranta; Jorma Toppari; Ulla Feldt-Rasmussen; Heqing Shen; Karl-Werner Schramm; Angelis Meri De

doi:10.1530/endoabs.56.P977

The placenta is a highly specialized organ, which ensures nutrient uptake, waste elimination, provides thermo-regulation, prevents passage of some xenobiotic molecules and regulates the quantity of thyroid hormones (TH) necessary for the fetal development. It is known, that even minor changes in maternal TH levels, can alter the fetal growth. Several factors can modify TH levels during pregnancy. Among them, increasing evidences show that prenatal exposure to persistent organic pollutants (POP), such as brominated flame-retardants (PBDE), polychlorinated dibenzo-p-dioxins and furans (PCDD/F), and polychlorinated biphenyls (PCB), could disrupt the maternal TH regulation system. Some years ago, we investigated the association between some POP measured in placenta and congenital cryptorchidism [1–3]. Congenital cryptorchidism is a genital malformation that occurs in 2-9% of newborns and it is associated with decreased semen quality and higher risk of testis cancer. Several factors seem implicated in such pathology; however, the possible relationship between cryptorchidism and thyroid hormone levels during the uterine life in boys born with such malformation has been poorly investigated. The aim of this study was to analyze the level of thyroxine (T4), 3,3′,5-triiodo-L-thyronine (T3), 3,3′,5′-triiodo-L-thyronine (rT3) in 58 placenta samples (28 cryptorchid boys, 30 controls) using a LC-MS method recently developed in our group [4]. The samples were randomly selected at the end of the 3rd trimester and collected at birth. The entire placenta was homogenized prior analysis and stored at −20° C.

Results: No difference was detected in thyroid hormone values between the case and control group. No differences between the two groups with respect to maternal smoking, maternal age, BMI, and birth weight was found. Only a difference was seen in gestational age between case and control. Although no association of placental thyroid hormone levels with congenital cryptorchidism was found, for more complete overview, future study should include TH measurement in maternal and fetal placenta as well as in the cord blood.

Reference:

Shen, H, et al. Placenta, 26, (2005), 512-514

Shen, H. et al. Human Reproduction, 23, (2008), 201-210

Shen, H. et al. Chemosphere, 67, (2007), S256-S262

De Angelis, M. et al. Journal of Chromatography B, 1033-1034, (2016), 413-420

Endocrine Abstracts

P977