Apelin 13 and Blood Pressure, Is there any Association in Pre-eclampsia? - A Case-control Study

Abstract

Introduction: Pre-eclampsia is a pregnancy specific disorder, characterised by the onset of hypertension and proteinuria. Pre-eclampsia is the leading cause of maternal, perinatal morbidity and mortality. The exact cause of pre-eclampsia is not known clearly and needs to be explored. Aim: To evaluate the maternal serum apelin 13 levels among pre-eclampsia and healthy pregnant women and also, to find the association between apelin 13 and blood pressure. Materials and Methods: A case-control study was conducted between Department of Biochemistry and Department of Obstetrics and Gynaecology, RL Jalappa Hospital and Research Centre, Kolar, Karnataka, India. After approval from the Institutional Ethics Committee and written informed consent from study subjects, a total of 270 pregnant women were recruited for this study. Among them, 135 pre-eclamptic women were considered as cases and 135 normotensive healthy pregnant women served as controls. According to the pre-eclampsia severity, cases were grouped into mild (n=47) and severe pre-eclampsia (n=88). Blood samples were collected from all the study subjects and was analysed for apelin 13 by Enzyme Linked Immunosorbent Assay (ELISA) method. Maternal and foetal adverse outcomes were recorded. Results were expressed as mean±Standard Deviation (SD). Categorical variables were expressed in percentages. Spearman’s correlation was applied and p<0.05 was considered significant. Results: The mean gestational age was 36.66±3.69 weeks which was, significantly low in pre-eclamptic women compared with healthy pregnant women. BMI (26.94±3.81 kg/m2), systolic (157.82±15.14 mmHg), diastolic (101.68±11.02 mmHg) and Mean Arterial Pressure (MAP) (120.20±11.12 mmHg), pulse rate (88.14±5.82 bpm), Aspartate Transaminase (AST) (25.25±12.49 IU/L) and Alanine Transaminase (ALT) (19.01±10.95 IU/L) were significantly increased in pre-eclamptic women when compared with control group. Mean maternal serum apelin 13 (341.44±218.63 pg/mL) concentrations were significantly lower in pre-eclampsia compared with healthy pregnant women. Maternal serum apelin 13 concentrations were negatively correlated with Systolic Blood Pressure (SBP) (r = -0.196), Diastolic Blood Pressure (DBP) (r = -0.172) and MAP (r =-0.204). Adverse maternal outcomes such as epigastric pain 75 (55.55%), oedema 62 (45.92%) and persistent headache 35 (25.92%) were higher in pre-eclamptic group. Additionally, adverse foetal outcomes were more in pre-eclamptic cases including significantly decreased birth weight (2.40±0.65), babies requiring Neonatal Intensive Care Unit (NICU) admission were 54 (40%), preterm birth (≤37 wks) in 50 (37.03%), Respiratory Distress Syndrome (RDS) 31 (22.96%), Small for Gestational Age (SGA) in 4 (2.96%) and Intra Uterine Death (IUD) in 11 (8.14%) babies. Conclusion: It was concluded from the present study that there was low maternal serum apelin 13 concentrations in pre-eclampsia and had negative correlation with blood pressure, suggesting its potential role in the pathophysiology of pre-eclampsia.