Altered endometrial expression of endothelial nitric oxide synthase in women with unexplained recurrent miscarriage and infertility

Infertility and Reproductive Health Research Center, Shahid Beheshti Medical University, Tehran, Iran.
Reproductive biomedicine online (Impact Factor: 3.02). 07/2012; 25(4):408-14. DOI: 10.1016/j.rbmo.2012.07.004
Source: PubMed


Endothelial nitric oxide synthase (eNOS) has diverse roles in the female reproductive system including a role in blastocyst implantation. Aberrant expression of eNOS could therefore be significant in the pathogenesis of disorders of implantation. In this study, eNOS protein and mRNA levels in the endometrium of women with recurrent miscarriages, unexplained infertility and a control group were determined by compartmental quantitative immunohistochemistry and real-time reverse-transcription PCR. eNOS was found to be immunolocalized to all layers of the endometrium and vascular endothelium. eNOS protein was higher in glandular epithelium (P = 0.004) and luminal epithelium (P = 0.002), but not vascular endothelium and stroma, in women with recurrent miscarriage. Similarly, in women with unexplained infertility, eNOS was significantly higher (P < 0.03) in luminal epithelium but not in any other compartments compared with the control group. The levels of mRNA confirmed the protein data, demonstrating higher eNOS mRNA in the endometrium of women with recurrent miscarriage and unexplained infertility compared with controls. In conclusion, increased expression of eNOS in glandular and luminal epithelium of the endometrium in women with recurrent miscarriages and unexplained infertility suggests a detrimental effect of excess nitric oxide in endometrial receptivity and implantation. RBM Online (c) 2012, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

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Available from: Marefat Ghaffari Novin, Feb 09, 2015
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    • "It is hypothesized that reduced eNOS and NO expression observed in IRSM women is possibly due to associated eNOS polymorphism. Contrary to our findings, there is only one report by Najafi et al. (2012) where a significantly higher endometrial eNOS expression in women with recurrent miscarriage is reported [9]. The group hypothesizes that excessive expression of eNOS causes excess NO generation, which leads to failure of early pregnancy maintenance. "
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    ABSTRACT: Endothelial nitric oxide synthase (eNOS) is an enzyme that influences placental human chorionic gonadotropin production during gestation. Previous studies have indicated an association between eNOS activity, implantation, and maintenance of pregnancy, but proposed associations between polymorphisms of the eNOS gene and recurrent miscarriage (RM) are controversial. To identify markers contributing to the genetic susceptibility to RM, we examined the potential association between RM and 8 single nucleotide polymorphisms (SNPs; rs1799983, rs2070744, rs11771443, rs3918188, rs2853796, rs7830, rs1541861, and rs2853792) of the eNOS gene using the MassARRAY system (Sequenom, USA). The enrolled participants included 192 RM patients and 201 women with normal fertility as controls. The results showed that rs1799983 at exon 7 of the eNOS gene was significantly associated with RM (genotype: chi-square = 15.071, P = 0.001; allele: chi-square = 6.250, P = 0.016). Another significant association was observed for rs11771443 in the promoter (genotype: chi-square = 6.259, P = 0.044; allele: chi-square = 7.076, P = 0.008). Furthermore, strong linkage disequilibrium was observed in 3 blocks (D' > 0.9), and significantly fewer T-T-G haplotypes (chi-square = 5.981, P = 0.015) residing in block 1 were found in RM patients. These findings point to a role for eNOS gene polymorphisms in RM in the Chinese Han population and may be informative for future genetic or neurobiological studies of RM.
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