Markers of insulin sensitivity in placentas and cord serum of intrauterine growth-restricted newborns.

Objective: Intrauterine growth restriction (IUGR) has been related to a higher incidence of insulin resistance in adult life, which is associated with low adiponectin and high resistin, insulin and interleukin (IL)-6 serum concentrations. This study assessed cortisol, insulin, total insulin receptor, resistin, adiponectin and IL-6 concentrations, as markers of insulin sensitivity, in placental lysates and cord serum of IUGR and appropriate for gestational age (AGA) newborns, to establish relationships among peptides and with growth parameters at birth.

Design And Patients: Whole villous tissue and cord serum at birth were collected from 24 AGA and 18 IUGR newborns of comparable gestational age.

Measurements: Hormonal and peptide concentrations were assayed in placental lysates and cord serum using specific commercial kits. Concentrations in lysates were adjusted per mg of total protein content.

Results: Cortisol, insulin and resistin concentrations and the total amount of insulin receptor were similar in both groups. IL-6 concentration in lysates was significantly higher in IUGR compared with AGA newborns. Adiponectin was significantly lower in lysates from IUGR compared with AGA newborns. Placental insulin and resistin concentrations were positively correlated. Placental adiponectin concentration was positively correlated with the weight of the placenta, birthweight and head circumference. IL-6 concentration in lysates was negatively correlated with birth length, birthweight and head circumference.

Conclusions: This study evaluated the markers of insulin sensitivity in the placentas of subjects born IUGR, showing new potential roles for adiponectin and IL-6 in particular, and suggesting a role for the placenta in the programming of these hormones.