Fetal sex-specific relations of human placental peroxisome proliferator-activated receptors gamma (PPAR-γ) expression with fetoplacental growth.

OBJECTIVE

Peroxisome proliferator-activated receptors gamma (PPAR-γ) regulates lipid storage and is involved in placental trophoblast differentiation and placental vasculature development. In this case-control study, associations between maternal, placental and neonatal parameters and placental PPAR-γ transcript abundance has been investigated in a set of well characterized small (SGA) and appropriate for gestational age (AGA) births.

METHODS

From 39 SGA and 51 AGA singleton pregnancies, placental samples were collected. Information on maternal and newborn anthropometry and clinical variables were recorded. Placental transcript abundance of PPAR-γ, with respect to housekeeping genes ACTB, YWHAZ and B2M, was evaluated using realtime quantitative PCR. Associations between maternal, placental and neonatal parameters and placental PPAR-γ transcript abundance was evaluated and levels of placental PPAR-γ transcript abundance was compared between SGA and AGA births.

RESULTS

Placental PPAR-γ transcript abundance was associated negatively with birth weight in all 90 births evaluated (β = -21.764, P = 0.026), in SGA births (n = 39, β = -19.533, P = 0.032) and in female AGA births (n = 29, β = -22.778, P = 0.041). Placental PPAR-γ transcript abundance was associated with placental length in all 90 births evaluated (β = -0.098, P = 0.005) and in SGA births (n = 39, β = -0.084, P = 0.032) and with placental breadth (n = 90, β = -0.095, P = 0.011). Female SGA placentae (n = 16) exhibited higher levels of placental PPAR-γ transcript levels compared to female AGA placentae (n = 29; P = 0.042).

CONCLUSION

Findings from this study indicate that fetal sex modulates the relations between placental PPAR-γ transcript abundance and birth weight. Repression of placental PPAR-γ expression was associated with better fetal growth, amongst SGA births of both sexes, and amongst female AGA births. The underlying mechanisms need to be addressed in future studies.