Expression of peroxisome proliferator-activated receptors, fatty acid binding protein-4 in placenta and their correlations with the prognosis of pre-eclampsia

Objective To examine the mRNA and protein expression of peroxisome proliferator-activated receptors (PPAR) and fatty acid binding protein-4 (FABP-4) in placenta, and to investigate their correlation with the prognosis of pre-eclampsia. Methods The data of 177 women who delivered from January 2013 to December 2015 in Chinese People′s Liberation Army No.94 Hospital were collected. Among them, 60 cases were term pregnancy and not in labor (TN); 46 cases were term pregnancy with preeclampsia and not in labor (TPE); 42 cases were preterm pregnancy and not in labor (PN); 29 cases were preterm pregnancy with pre-eclampsia and not in labor (PPE). Real-time PCR and western blot were used to examine the PPAR and FABP-4 mRNA expression and protein expression in placentas. And linear correlation was used to analyze the relationship between PPAR and FABP-4 protein expression and the prognosis of pre-eclampsia. Results (1) Real-time PCR showed that: ① PPAR-α, PPAR-β mRNA expression were not statistically different between placentas from TN and TPE (P>0.05), but PPAR-γ mRNA level in TPE (0.59±0.17) was significantly lower than that in TN (0.81±0.19, P 0.05) . However, PPAR-γ mRNA in the PPE group (0.33±0.14) was significantly lower than that in PN (0.52±0.16, P<0.01), and FABP-4 mRNA level in the PPE group (0.80±0.29) was significantly higher than in the PN group (0.63±0.22, P<0.01). (2) Western-blot showed the same tendency as the mRNA results. ①There were no statistical differences in the protein expression of PPAR-α, PPAR-β, not in term groups (TN and TPE) , nor in premature groups (PN and PPE) . PPAR-γ protein level in the TPE group (0.46±0.17) was significantly lower than that in TN (0.65±0.20, P<0.01) and FABP-4 protein level in the TPE group (0.60±0.19) was significantly higher than that in the TN group (0.50±0.21, P<0.05). ②The PPAR-γ protein level in the PPE group (0.30±0.16) was significantly lower than that in the PN group (0.61±0.16, P<0.05), while the FABP-4 protein expression in the PPE group (0.58±0.19) was significantly higher than that in the PN group (0.40±0.19, P<0.05). (3) Linear correlation showed that: ①PPAR-γ protein expression correlated negatively with FABP-4 protein expresssion [P<0.01, R2=0.12 in the term groups (TN+TPE) , R2=0.15 in the premature groups (PN+PPE) ]. ②PPAR-γ protein expression correlated negatively with blood pressure recovery time, 24-hour urinary protein quantification and blood lipid recovery time (P<0.01, R2=0.37, 0.35, 0.18). FABP-4 protein expression correlated positively with lipid recovery time and blood cholesterol concentrations (P<0.01, R2=0.13, 0.25). Conclusions The expression of PPAR-γ decreases in placentas from patients with pre-eclampsia, while the expression of FABP-4 increases. The expression of FABP-4 correlates negatively with the expression of PPAR-γ, and both are associated with the prognosis of pre-eclampsia. Key words: Pre-eclampia; Placenta; Peroxisome proliferator-activated receptors; Fatty acid binding proteins; Prognosis