Retinol binding protein 4 – a novel association with early-onset preeclampsia

Abstract

Objective: Dysregulation of maternal circulating adipokines has been implicated in several ''great obstetrical syndromes'' including preeclampsia (PE), small-for-gestational age (SGA) neonate and fetal death (FD). It has been suggested that adipokines provide a molecular link between metabolic derangements and inflammatory response in complicated pregnancies. Retinol binding protein 4 (RBP4), a novel adipokine, plays a role in obesity-related disorders, as well as in the regulation of the immune response. The aim of this study was to determine whether there are changes in maternal plasma concentrations of RBP4 in patients with PE and in those with an SGA neonate or FD. Study design: This cross-sectional study included patients in the following groups: 1) normal pregnancy (ns134); 2) PE (ns104); 3) SGA neonate (ns28); and 4) FD (ns 37). Maternal plasma RBP4 concentrations were determined by ELISA. Non-parametric statistics were used for analysis. Results: 1) The median maternal plasma RBP4 concentration was higher among patients with PE than in those with a normal pregnancy (Ps0.03); 2) The median maternal plasma RBP4 concentrations of patients with preterm PE (-37 weeks) was higher than that of those with term PE (Ps0.017) and than that of those with a normal pregnancy (Ps0.002); 3) The median maternal plasma RBP4 concentration did not differ significantly between patients with a normal pregnancy and those with an SGA neonate or with an FD; 4) Among normal pregnant women, the maternal plasma RBP4 concentrations did not correlate with pre-pregnancy body mass index, gestational age at blood sampling and neonatal birthweight. Conclusions: 1) Preeclampsia, but not pregnancy with an SGA neonate or an FD, is associated with a higher median maternal plasma concentration of RBP4 than normal pregnancy; 2) Preterm PE, and specifically early-onset PE, is associated with higher median RBP4 concentrations in maternal plasma compared to term PE. These findings suggest a role for RBP4 in the pathogenesis of preterm PE, but not in SGA and FD.

The Positive Correlation between Cord Serum Retinol-Binding Protein 4 Concentrations and Fetal Growth

“…The simple correlation model showed a negative relationship between maternal RBP4 levels and birth weights, but this correlation disappeared after adjustment for maternal age, maternal insulin levels, maternal BMI, and cord serum RBP4 and insulin (table 2). This finding is consistent with a recent study by Vaisbuch et al [27] who argued that there is no significant difference in maternal plasma RBP4 levels between women with fetuses small for their gestational age and those with fetuses appropriate for their gestational age. However, a recent study conducted by Mazaki-Tovi et al [28] reported that mothers without gestational DM but with large for their gestational age neonates had a higher maternal plasma concentration of RBP4 than women with appropriate for their gestational age newborns.…”

Retinol-binding protein 4 and insulin resistance in preeclampsia

“…So far, we have found only a few reports about the relationship between RBP4 and preeclampsia. Two studies demonstrated that the RBP4 level was increased in obese patients with preeclampsia compared with normal controls [20,21], and our previous report demonstrated a significant increase of RBP4 in late onset patients with preeclampsia compared with normal late pregnancy controls [22]. In contrast, Stephan et al [23] observed no significant difference in RBP4 levels between patients with preeclampsia and normal control subjects, but all the patients in their study were lean and showed early-onset preeclampsia.…”

Clinical immunology Retinol-binding protein 4 levels are related to maternal triglyceride levels

“…Previously plasma RBP4 levels were found to increase with increasing TG levels [6,27,28]. On the contrary, in a recent study no association was reported between maternal RBP4 levels and prepregnancy BMI, birth weight, parameters of insulin resistance and TG levels [29]. Higher maternal plasma levels of RBP4 were reported to be associated with larger neonates both in women with and without gestational diabetes mellitus [5], high maternal RBP4 concentrations were attributed to maternal glucose metabolism.…”