[Correlation of the expressions of advanced glycation end products and its receptor in serum and placenta with the pathogenesis of preeclampsia].

OBJECTIVE: To investigate the correlation of the expressions of advanced glycation end products (AGE) and the receptor for advanced glycation end products (RAGE) in serum and placenta with the pathogenesis of preeclampsia. METHODS: From December 2013 to June 2014, 32 women with severe preeclampsia who received cesarean section in the Affiliated Hospital of Qingdao University were recruited in the study, defined as the severe preeclampsia group. 30 healthy pregnant women who received cesarean section in the same hospital were recruited as the control group. ELISA was used to measure the maternal serum AGE, soluble receptor for advanced glycation end products (sRAGE) and tumor necrosis factor-α (TNF-α) in these women. Furthermore, ELISA was also used to measure AGE and TNF-α in the placenta. The localizations of AGE and RAGE protein in placentas were detected by immunohistochemical SP method. RAGE and TNF-α mRNA expression in placentas were measured by real-time quantitative PCR. AGE, RAGE and TNF-α protein expression in placentas were measured by western blot, respectively. RESULTS: (1) The serum levels of AGE, sRAGE and TNF-α in the severe preeclampsia group were (538 ± 75), (367 ± 86) and (322 ± 40) ng/L, respectively. They were significantly higher than those in the control group [(454 ± 50), (286 ± 35) and (270 ± 35) ng/L, respectively] (P < 0.05). The levels of AGE showed positive correlation with the levels of TNF-α (r = 0.588, P < 0.05), while the levels of sRAGE showed no correlation with TNF-α (r = -0.041, P > 0.05). (2) In the severe preeclampsia group, the levels of AGE and TNF-α in placentas were (500 ± 82) and (334 ± 57) ng/L, which were higher than those in the control group [(431 ± 74) and (263 ± 46) ng/L, respectively] (P < 0.05). The levels of AGE showed positive correlation with the levels of TNF-ɑ (r = 0.406, P < 0.05). (3) AGE and RAGE protein mainly located in the syncytiotrophoblasts, macrophages and vascular endothelial cells in the placentas of the two groups. AGE expressed mainly in the cytoplasm, and RAGE expressed in the cytoplasm and cell membranes. (4) RAGE and TNF-α mRNA expression in the placentas of the severe preeclampsia group were 12.6 ± 4.6 and 10.4 ± 2.4, which were significantly higher than those in the control group (0.9 ± 0.4 and 3.5 ± 0.9, P < 0.01). (5) The expressions of AGE, RAGE and TNF-α protein in placentas of the severe preeclampsia group were 0.68 ± 0.06, 0.82 ± 0.08 and 0.76 ± 0.08. All were significantly higher than those of the control group (0.46 ± 0.05, 0.42 ± 0.09 and 0.52 ± 0.07; P < 0.01). CONCLUSIONS: The levels of AGE and RAGE in serum and placentas elevated in the severe preeclampsia group, and the expression of TNF-α also elevated. These indicated that AGE and RAGE might be involved in the systemic inflammatory response and local inflammatory response in placentas, and then caused the preeclampsia.