Endothelial nitric oxide synthase (eNOS) gene polymorphism, nitric oxide and progesterone levels in unexplained recurrent pregnancy loss

Abstract

This study was conducted in order to determine the relationships between promoter-786 T> C, exon 7 Glu298Asp (894 G> T) and intron 4 (4a4b) VNTR polymorphisms of eNOS gene, serum nitric oxide (NO) and progesterone (P4) levels, and unexplained recurrent pregnancy loss (URPL) in Palestinian women residing in Gaza strip. The study presented here is an association study with a case-control design. The study population consisted of 45 (30 non-pregnant and 15 pregnant) women who suffered from URPL, and 45 (30 non-pregnant and 15 pregnant) healthy women matched for age and without a previous history of RPL. Two blood samples were collected from each subject after fasting for 10-12 hours, one was whole blood and the other was serum. DNA extracted from blood samples of all subjects was investigated for the three eNOS polymorphisms using PCR or PCR-RFLP. Serum NO level was measured using a colorimetric method. Serum progesterone was measured using Immulite 1000 Analyzer. The study showed that the promoter-786T> C polymorphism C allele (represented by CC+ CT genotypes) is significantly associated with increased risk of RPL, where it occurred with a higher frequency in URPL women and was associated with decreased serum NO levels in this group (all P-values< 0.001). Neither exon 7 Glu298Asp (894G> T) nor intron 4 (4a4b) VNTR polymorphisms was significantly associated with RPL risk in the study population. The serum NO levels were lower in URPL patients as compared to their respective controls (P-value= 0.004). The study also pointed to a positive proportional correlation between serum nitric …