Maternal serum Apelin 13 and APLN gene promoter variant-1860T > C in preeclampsia

Objective: To evaluate the apelin (APLN) -1860 T > C (rs56204867) polymorphism and maternal serum apelin 13 levels in preeclampsia and its association with blood pressure. Methods: This case-control study was conducted in department of Biochemistry, Sri Devaraj Urs Medical College, Karnataka, India. A total of 181 subjects were enrolled in the study from department of Department of Obstetrics and Gynecology. The recruited women were grouped as: Group-I (n = 91) cases with preeclampsia and Group-II (n = 90) normotensive healthy pregnant women as controls. Under aseptic conditions, the collected 5 mL blood was distributed for serum separation (3 mL) and genetic analysis (2 mL). Serum was stored at -80 degrees C after centrifugation at 3000 rpm for 10 min. The collected five mL urine sample was used for urinary protein analysis by dipstick method. The APLN gene -1860 T > C polymorphism and Apelin 13 levels were analyzed by molecular methods and ELISA technique respectively. Birth weight and demographic details were recorded. Results: In the present study, no significant difference was observed for mean gestational age and maternal age. Systolic (158.7 +/- 14.0 mmHg) and diastolic (104.9 +/- 10.7 mmHg) blood pressure, and mean arterial pressure (MAP) (123.0 +/- 11.1 mmHg) (p-value .001) were significantly increased in preeclamptic women compared with healthy pregnant women. Birth weight (2.4 +/- 0.5 kg) (p-value .001) was significantly decreased in babies born to preeclamptic mothers. Birth weights were also expressed in centiles, according to Fenton Chart. Number of small for gestational age (SGA) babies were more in preeclampsia (n = 55) than healthy pregnant women (n = 28). Mean maternal serum apelin 13 (239.4 +/- 126.3 pg/mL) (p-value .001) concentrations were significantly lower in preeclampsia compared with healthy controls. Maternal serum apelin 13 concentration in preeclampsia was negatively correlated with systolic blood pressure (r = -0.235), diastolic blood pressure (r= -0.172) and mean arterial pressure (r = -0. 206). However, maternal serum apelin 13 levels showed insignificant positive correlation with age, gestational age and birth weight. The genotype and allele frequencies of APLN gene were found significant between study groups as in preeclampsia (chi(2) = 11.69; df = 2; p = .0028 and chi 2 = 14.27; df = 1; p = .00013 respectively). CC genotype and C allele of APLN - 1860 T > C site was high in preeclampsia. Conclusion: Study concludes that preeclamptic women have low level of serum apelin 13 and -1860 T > C polymorphism at APLN gene promoter site with increased allelic frequency of CC genotype and C allele compared to normotensive pregnant women. And this evidence may link to cardiac complications in preeclamptic women after delivery in later stage.