Genetic Variations in Angiotensinogen Gene and Risk of Preeclampsia: A Pilot Study

Polymorphisms in myeloperoxidase and tissue inhibitor of metalloproteinase-1 genes and their association with preeclampsia in the Chinese Han population

Hypertensive disorders of pregnancy (HDP) are multifaceted syndromes unique to pregnancy, characterized by increased blood pressure, edema, and proteinuria. Patients with HDP exhibit signs of endothelial dysfunction, possibly linked to increased myeloperoxidase (MPO) level and aberrant oxidative stress. Additionally, altered level of tissue inhibitor of metalloproteinase-1 (TIMP1) protein is associated with placental ischemia, hypoxia, and maternal vascular endothelial damage. Preeclampsia (PE) represents a critical stage of HDP that poses severe threats to maternal and fetal safety. This study aimed to determine the relationship between MPO and TIMP1 polymorphisms and the risk of PE in the Chinese Han population. Single nucleotide polymorphisms (SNPs), including MPO rs7208693, MPO rs2243828, and TIMP1 rs6609533, were genotyped in 170 patients with PE and 303 control participants. No significant association was observed between MPO polymorphisms (rs7208693 and rs2243828) and the risk of PE, whereas significant association between the TIMP1 rs6609533 A > G SNP and PE susceptibility was found. Specifically, individuals with the GG or AG genotypes had elevated risk of PE compared to those harboring the AA genotype. Furthermore, in the PE group, patients carrying the G allele were more likely to experience fetal growth restriction (FGR). In the non-PE group, the association between the G allele and the risk of FGR was not evident. In conclusion, the TIMP1 rs6609533 G allele in Chinese Han women was identified as a risk factor for PE. Our results indicated that the TIMP1 rs6609533 SNP can serve as a biomarker for the clinical diagnosis and treatment of PE.

Second Trimester Amniotic Fluid Angiotensinogen Levels Linked to Increased Fetal Birth Weight and Shorter Gestational Age in Term Pregnancies

BACKGROUND

Despite the considerable progress made in recent years in fetal assessment, the etiology of fetal growth disturbances is not as yet well understood. In an effort to enhance our knowledge in this area, we investigated the associations of the amniotic fluid angiotensinogen of the renin-angiotensin system with fetal growth abnormalities.

METHODS

We collected amniotic fluid samples from 70 pregnant women who underwent amniocentesis during their early second trimester. Birth weight was documented upon delivery, after which the embryos corresponding to the respective amniotic fluid samples were categorized into three groups as follows: small for gestational age (SGA), appropriate for gestational age (AGA), and large for gestational age (LGA). Amniotic fluid angiotensinogen levels were determined by using ELISA kits.

RESULTS

Mean angiotensinogen values were 3885 ng/mL (range: 1625-5375 ng/mL), 4885 ng/mL (range: 1580-8460 ng/mL), and 4670 ng/mL (range: 1995-7250 ng/mL) in the SGA, LGA, and AGA fetuses, respectively. The concentrations in the three groups were not statistically significantly different. Although there were wide discrepancies between the mean values of the subgroups, the large confidence intervals in the three groups negatively affected the statistical analysis. However, multiple regression analysis revealed a statistically significant negative correlation between the angiotensinogen levels and gestational age and a statistically significant positive correlation between the birth weight and angiotensinogen levels.

DISCUSSION

Our findings suggest that fetal growth abnormalities did not correlate with differences in the amniotic fluid levels of angiotensinogen in early second trimester pregnancies. However, increased angiotensinogen levels were found to be consistent with a smaller gestational age at birth and increased BMI of neonates.