Recurrent early pregnancy loss and endothelial nitric oxide synthase gene polymorphisms

A meta-analysis for association of eNOS VNTR 4b/a, - 786 T > C and + 894G > T polymorphisms with risk of recurrent pregnancy loss

BACKGROUND

The association of polymorphisms at nitric oxide synthases (eNOS) gene with recurrent pregnancy loss (RPL) susceptibility has been the focus of attention in several studies. However, the conclusions have been divergent and controversial. Therefore, we performed this study to precisely evaluate the association of eNOS polymorphisms with the risk of RPL.

METHODS

A universal search in PubMed, Web of Knowledge, SciELO, MedRxiv, Scopus and web of Science was performed to identify relevant studies up to January 25, 2020.

RESULTS

A total of 39 eligible studies including 15 studies with 2274 cases and 1933 controls on VNTR 4b/a, nine studies with 1640 cases and 1268 controls on -786C > T, and 15 studies with 2660 cases and 2557 controls on + 894G > T polymorphism were selected. Pooled data revealed that eNOS VNTR 4b/a (dominant model: OR = 1.174, 95% CI 1.021-1.350, p = 0.025) and + 894G > T (allele model: OR = 1.278, 95% CI 1.024-1.595, p = 0.030; homozygote model: OR = 1.442, 95% CI 1.084-1.917, p = 0.012; dominant model: OR = 1.305, 95% CI 1.006-1.693, p = 0.045; and recessive model: OR = 1.378, 95% CI 1.045-1.817, p = 0.023) polymorphisms were significantly associated with an increased risk of RPL, but not  - 786 T > C. Stratified analysis by ethnicity revealed that the eNOS + 894G > T was associated with RPL risk in Asians.

CONCLUSIONS

To sum up, our results indicated that the eNOS VNTR 4b/a and + 894G > T polymorphisms might be contributing to RPL development, but not the  - 786C > T polymorphism.

Genetics of recurrent pregnancy loss among Iranian population

Background

Recurrent pregnancy loss (RPL) is one of the most common reproductive disorders which is defined as the occurrence of recurrent miscarriage before 24 weeks of gestation and is observed among 1%–5% of women.

Methods

Various factors are associated with RPL such as immunological disorders, maternal age, obesity, alcohol, chromosomal abnormality, endocrine disorders, and uterine abnormalities. About half of the RPL cases are related with chromosomal abnormalities. Therefore, RPL genetic tests are mainly limited to karyotyping. However, there is a significant proportion of RPL cases without any chromosomal abnormalities that can be related to the single‐gene aberrations. Therefore, it is required to prepare a diagnostic panel of genetic markers besides karyotyping.

Results

In the present review, we have summarized all the significant reported genes until now which are associated with RPL among Iranian women. We categorized all the reported genes based on their cellular and molecular functions in order to determine the molecular bases of RPL in this population.

Conclusion

This review paves the way of introducing a population‐based diagnostic panel of genetic markers for the first time among Iranian RPL cases. Moreover, this review clarifies the genetic and molecular bases of RPL in this population.

Pathogenetic factors involved in recurrent pregnancy loss from multiple aspects

Recurrent pregnancy loss (RPL) is a common complication in obstetrics, affecting about 5% of women of childbearing age. An increase in the number of abortions results in escalation in the risk of miscarriage. Although concentrated research has identified numerous causes for RPL, about 50% of them remain unexplained. Pregnancy is a complex process, comprising fertilization, implantation, organ and tissue differentiation, and fetal growth, which is effectively controlled by a number of both maternal and fetal factors. An example is the immune response, in which T cells and natural killer cells participate, and inflammation mediated by tumor necrosis factor or colony-stimulating factor, which hinders embryo implantation. Furthermore, vitamin D affects glucose metabolism and inhibits embryonic development, whereas microRNA has a negative effect on the gene expression of embryo implantation and development. This review examines the causes of RPL from multiple perspectives, and focuses on the numerous factors that may result in RPL.

Gene polymorphism associated with endothelial nitric oxide synthase (4VNTR, G894T, C786T) and unexplained recurrent spontaneous abortion risk: A meta-analysis

To evaluate the association between endothelial nitric oxide synthase gene polymorphisms (4VNTR A/B, G894T, C786T) and risk of URSA.Related case-control studies were collected by computers. A meta-analysis was conducted using Stata 12.0 software to assess the strength of association.Altogether 37 articles were examining the relationship between endothelial nitric oxide synthase gene polymorphisms and URSA, among which sixteen (16) studies were related to 4VNTR, twelve (12) to G894T, and nine (9) to C786T, the study suggested that 4VNTR A/B polymorphism was closely connected with URSA risk under all gene models except for recessive model (AA vs. BB + AB). The integrated result which indicated the association between G894T gene mutation and URSA risk had been shown under homozygote (TT vs. GG; OR 1.585, 95%CI 1.175-2.138) and recessive models (TT vs. TG + GG; OR 1.530, 95%CI 1.142-2.052). Considering heterogeneity in the remaining gene models, subgroup analysis was performed on ethnicity, and the results showed that it was the dominant (TT + TG vs. GG; OR 1.585, 95%CI 1.175-2.138) and additive models (T vs. G; OR 1.727, 95%CI 1.372-2.175) of G894T in Asians and the heterozygote model (TG vs. GG; OR 1.015, 95%CI 0.846-1.217) in Caucasians that were associated with URSA (P < .05). Besides C786T gene was significantly connected with URSA under all models except for additive model (T vs. C).It is of great guiding significance for screening out and preventing URSA among high-risk women via testing on 4VNTR A/B, G894T, C786T eNOS under gene models mentioned above which are closely associated with URSA.

Association of endothelial nitric oxide synthase gene variants (-786 T>C, intron 4 b/a VNTR and 894 G>T) with idiopathic recurrent pregnancy loss: A case-control study with haplotype and in silico analysis

OBJECTIVE(S)

Many lines of evidence suggest that reduced production of nitric oxide (NO) due to single nucleotide polymorphisms in endothelial nitric oxide synthase (eNOS) gene may affect the implantation and maintenance of pregnancy. Accordingly, our objective was to investigate whether the eNOS polymorphisms (-786 T>C, intron 4 b/a VNTR and 894 G>T) and haplotypes may be associated with increased susceptibility to recurrent pregnancy loss (RPL).

STUDY DESIGN

A total of 130 women with a history of two or more unexplained consecutive first trimester miscarriages and 110 ethnically matched women with at least two normal pregnancies and no history of pregnancy loss were included in the study as cases and controls, respectively. To identify the genotypes, we used polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP) methods In addition, an in silico analysis was conducted to predict the possible effects of the eNOS 894 G>T polymorphism on the structure and function of eNOS mRNA and protein using prediction servers.

RESULTS

Our findings revealed that the prevalence of eNOS -786 T>C polymorphism, eNOS -786C allele and TC+CC genotype in cases were significantly higher than those in healthy controls (p<0.05). Also, the combination genotypes -786TT/4b4a and -786TT/894GG were significantly associated with reduced risk of RPL. We also found that the C-4a-G haplotype of the eNOS gene studied polymorphisms was significantly associated with a predisposition to RPL (odds ratio, 3.219; 95% confidence interval, 1.649-6.282; p=0.0003). The in silico analysis showed that the eNOS 894 G>T polymorphism couldn't affects eNOS mRNA and protein significantly.

CONCLUSION

Our findings provide evidence to support the hypothesis that eNOS -786 T>C polymorphism and the -786C-4a-894G haplotype are associated with the high risk of RPL.

Endothelial nitric oxide gene polymorphisms and their association with coronary artery disease in Tunisian population

OBJECTIVE

By releasing mediators, like nitric oxide (NO), vascular endothelium is considered so significant in the process of atherosclerotic . In fact, the major functions of NO consist in inhibiting the activation of platelet, relaxing the muscles (vascular and smooth ones), and modulating the growth and the migration of cells (vascular and smooth ones). Therefore, this process makes the endothelial nitric oxide synthase (NOS3) considerably important because it possesses atheroprotective activity. Polymophisms, rs1808593 (10G/T) as well as rs891512 (G24943A) within NOS3 gene, play major role in the coronary artery disease (CAD) development. The aim of the study is to evaluate the relationship between the 10G/T and G24943A polymorphisms and the CAD among Tunisian individuals.

METHODS

We included, in this survey, a set of 274 patients suffering from CAD together with 162 normotensive subjects. The PCR-RFLP was applied to analyze the polymorphism of intron 23 (10G/T) gene, while the ASA-PCR was used to analyze the intronic G24943A gene polymorphism. Overall and subgroup analyses were performed. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the association between NOS3 10G/T and G24943A polymorphisms as well as CAD risk. Statistical analysis was performed with SPSS V.10.

RESULTS

The genotype frequencies for G24943A polymorphism differed significantly between the CAD patients and the controls. The former had a frequency of 11.4% for the AA genotype, 34.7% for the GA genotype and 53.9% for the GG genotype. The latter had a frequency of only 2.5% for the AA genotype, 29.7% for the GA genotype and 67.7% for the GG genotype (χ2=7.62; OR=1.79; p=0.006). The CAD patient group showed a significantly-higher frequency of the A allele compared to the controls (0.28 vs. 0.16; χ2=15.20; p<0.001). The odds ratio of CAD for A vs. G allele frequency was statistically significant 1.99 (1.4-2.82) at 95% CI. The genotype distribution for the 3 investigated variants of 10G/T were not significantly different between CAD and control subjects (χ2=1.46; OR=1.72; p=0.22). Whereas, 10G/T has revealed barely allelic (χ2=4.45; OR=2.3; p=0.034) correlation with coronary artery disease Conclusion: The present study was designed so that there would be an association between the CAD and NOS3 polymorphism (G24943A). However, these results have proven that the polymorphism of 10G/T is not associated with CAD in the Tunisian population.

A critical update on endothelial nitric oxide synthase gene variations in women with idiopathic recurrent spontaneous abortion: genetic association study, systematic review and meta-analyses

A number of case-control studies investigated the association between idiopathic recurrent spontaneous abortion (IRSA) and variations in the gene encoding endothelial nitric oxide synthase (NOS3), but yielded contradictory results. Our aim was to test the association of the NOS3 variable number of tandem repeats (VNTR) in intron 4 and +894 G/T single-nucleotide polymorphism (SNP) with IRSA in Slovenian women (148 IRSA and 149 control women), conduct a systematic review of literature on the association between NOS3 gene variations and IRSA, and perform meta-analyses of studies that met the inclusion criteria, defined by virtue of the European Society for Human Reproduction and Embryology evidence-based guidelines for recurrent spontaneous abortion. Genotyping was performed using PCR and restriction fragment length polymorphism methods. The systematic review of literature (English language) was conducted using PubMed and Scopus databases, to 1 November 2014. We determined no association of IRSA with the VNTR in intron 4 and +894 G/T SNP in Slovenian women. Furthermore, 16 case-control studies were identified on the association between 15 NOS3 gene variations and IRSA. However, significant inconsistencies exist in the selection criteria of patients and controls between studies. The meta-analysis of VNTR in intron 4 was performed on five studies (894 patients, 944 controls), whereas the meta-analysis of +894 G/T SNP included six studies (1111 patients, 1121 controls). The association with IRSA was significant for the +894 G/T SNP under the dominant genetic model (GT+TT versus GG) based on fixed (odds ratio (OR) = 1.54, 95% confidence interval (CI) = 1.28-1.86, P = <0.01) and random effects models (OR = 1.54, 95% CI = 1.03-2.31, P = 0.03). In conclusion, the GT and TT genotypes of the +894 G/T SNP in women might contribute to a predisposition to IRSA. Additional genetic association and functional studies in different populations with larger numbers of participants and a uniformly defined IRSA are needed to clarify the contribution of NOS3 +894 G/T gene variation to IRSA.

Genetic association studies of endothelial nitric oxide synthase gene polymorphisms in women with unexplained recurrent pregnancy loss: a systematic and meta-analysis

Recurrent pregnancy loss (RPL) is a multifactorial disorder, both genetic and environmental factors contribute to the development of RPL. Recently, the association between endothelial nitric oxide synthase (eNOS) gene polymorphisms and unexplained recurrent pregnancy loss (URPL) has been reported, and the results were inconsistent. Hence, we performed the meta-analysis to drive a more precise estimation of association between eNOS polymorphisms and URPL. Odds ratio (OR) and its 95% confidence interval were calculated under co-dominant (AA vs. BB, TT vs. GG) and additive (A vs. B, T vs. G) genetic models. Studies of eNOS intron 4 VNTR and Glu298Asp were separated by ethnicities. 13 studies included 1,769 URPL cases and 1,376 healthy controls on eNOS intron 4 VNTR polymorphism, and 11 studies were involved in Glu298Asp polymorphism with 1,498 URPL cases and 1,123 healthy controls. The integrated results showed that eNOS Glu298Asp polymorphism was associated with URPL [ORs were 1.91 (1.42-2.56), P < 0.001; 1.67 (1.36-2.04), P < 0.001, respectively]. When analyses were separated by ethnic subgroups, the association between eNOS Glu298Asp polymorphism and URPL was only observed in East Asians [OR = 1.88 (1.52-2.33), P < 0.001 under additive model], and there was no association between eNOS intron 4 VNTR polymorphism and URPL in Caucasians and East Asians. The results indicated a significant association between eNOS Glu298Asp polymorphism and URPL in East Asians. No association was observed between eNOS intron 4 VNTR polymorphism and URPL in Caucasians and East Asians.

Identification of key contributory factors responsible for vascular dysfunction in idiopathic recurrent spontaneous miscarriage

Poor endometrial perfusion during implantation window is reported to be one of the possible causes of idiopathic recurrent spontaneous miscarriage (IRSM). We have tested the hypothesis that certain angiogenic and vasoactive factors are associated with vascular dysfunction during implantation window in IRSM and, therefore, could play a contributory role in making the endometrium unreceptive in these women. This is a prospective case-controlled study carried out on 66 women with IRSM and age and BMI matched 50 fertile women serving as controls. Endometrial expression of pro-inflammatory (IL-1β, TNF-α, IFN-γ, TGF-β1), anti-inflammatory (IL-4, -10), angiogenesis-associated cytokines (IL-2, -6, -8), angiogenic and vasoactive factors including prostaglandin E2 (PGE2), vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), nitric oxide (NO) and adrenomedullin (ADM) were measured during implantation window by ELISA. Subendometrial blood flow (SEBF) was assessed by color Doppler ultrasonography. Multivariate analysis was used to identify the significant factor(s) responsible for vascular dysfunction in IRSM women during window of implantation and further correlated with vascular dysfunction. Endometrial expression of pro-inflammatory cytokines and PGE2 were up-regulated and anti-inflammatory and angiogenesis-associated cytokines down-regulated in IRSM women as compared with controls. Further, the angiogenic and vasoactive factors including VEGF, eNOS, NO and ADM were found to be down-regulated and SEBF grossly affected in these women. Multivariate analysis identified IL-10, followed by VEGF and eNOS as the major factors contributing towards vascular dysfunction in IRSM women. Moreover, these factors strongly correlated with blood flow impairment. This study provides an understanding that IL-10, VEGF and eNOS are the principal key components having a contributory role in endometrial vascular dysfunction in women with IRSM. Down-regulation of these factors is also associated with impaired endometrial perfusion which possibly makes the endometrium unreceptive that may eventually cause early pregnancy loss.

Association of kinase insert domain-containing receptor (KDR) gene polymorphisms with idiopathic recurrent spontaneous abortion in Korean women

OBJECTIVE

To investigate whether kinase insert domain-containing receptor (KDR) gene polymorphisms are risk factors for recurrent spontaneous abortion (RSA) in Korean women.

DESIGN

Case-control study.

SETTING

University hospital.

PATIENT(S)

Three hundred twenty-seven idiopathic RSA patients and 230 controls with Korean ethnicity.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The KDR -604T→C (rs2071559), 1192G→A (rs2305948), and 1719A→T (rs1870377) polymorphisms were assessed.

RESULT(S)

KDR -604TC and TC+CC genotypes were more prevalent in RSA patients than in controls (adjusted odds ratio [AOR] = 2.091 and 2.076, respectively). KDR -604TC+CC/1192GG, -604TC+CC/1719AA, and -604TC+CC/1719TA+TT combined genotypes exhibited higher frequencies in RSA patients (AOR = 2.422, 2.611, and 2.216, respectively). KDR -604C/1192G/1719A, -604C/1192G/1719T, -604C/1192G, -604C/1719A, and -604C/1719T haplotype frequencies were higher in RSA patients (OR = 1.778, 2.659, 2.089, 1.678, and 1.806, respectively), whereas -604T/1192G/1719A, -604T/1192G, and -604T/1719A haplotype frequencies were lower in RSA patients (OR = 2.422, 2.611, and 2.216, respectively). No association was found between RSA and KDR 1192G→A or 1719A→T.

CONCLUSION(S)

An association between the KDR -604T→C polymorphism and RSA was found in Korean women. Carriers of the -604C variant allele were more frequent among RSA patients than among controls, suggesting that KDR -604C may confer RSA risk. The association of 1719A→T with RSA that was found in Taiwanese Han women was not observed in Korean women.

Vascular endothelial growth factor gene polymorphisms in Korean patients with premature ovarian failure

OBJECTIVE

To study the association of vascular endothelial growth factor (VEGF) polymorphisms (-2578C>A, -1154G>A, -634G>C, and 936C>T) with premature ovarian failure (POF) in Korean patients.

STUDY DESIGN

Prospective case-control study. One hundred and thirty five patients with POF and confirmed serum follicle-stimulating hormone levels of >40IU/L before the age of 40 years and 120 healthy controls with at least one live birth, regular menstrual cycles, and karyotype 46, XX.

RESULTS

POF patients exhibited significantly different frequencies of the VEGF -1154GA genotype (odds ratio [OR], 2.002; 95% confidence interval [CI], 1.116-3.592; P=0.019), and -2578CA+AA/-1154GA+AA combination genotype (OR, 1.805; 95% CI, 1.013-3.217; P=0.044) compared to the control group. The frequency of the -2578A/-1154A haplotype (OR, 1.647; 95% CI, 1.017-2.677; P=0.041) was significantly higher in the POF group than in the control group.

CONCLUSION

The VEGF -1154G>A mutation, -2578CA+AA/-1154GA+AA combination genotype, and -2578A/-1154A haplotype are significantly associated with POF in Korean women.

Genetic association studies of angiogenesis- and vasoconstriction-related genes in women with recurrent pregnancy loss: a systematic review and meta-analysis

BACKGROUND

Angiogenesis and an adequate blood supply are critical for several steps in human early pregnancy. Some studies have reported angiogenesis- and vasoconstriction-related genes are associated with recurrent pregnancy loss (RPL), but their sample size was limited. This study was conducted to investigate the genetic association between these angiogenesis- and vasoconstriction-related genes and idiopathic RPL, using meta-analyses.

METHODS

A systematic review of the published literature from MEDLINE and EMBASE databases was conducted and investigations of an angiogenesis- and vasoconstriction-related gene polymorphism in RPL reported more than three times were selected. Aggregating data from eligible studies were integrated into meta-analyses by means of random effects models.

RESULTS

Of 185 potentially relevant studies, 18 case-control studies comprising a total of 2397 RPL patients and 1760 controls were included into the meta-analyses. Among these genetic association studies were 4 reports of vascular endothelial growth factor (VEGF) (-1154G>A) polymorphisms, 4 reports of p53 (codon72) and 10 reports of endothelial nitric oxide synthase (eNOS) (B/A, Glu298Asp) with RPL. The integrated results showed that VEGF (-1154G>A), p53 (codon 72) and eNOS (Glu298Asp) polymorphisms were significantly associated with RPL, and their summary odd ratios [95% confidence interval (CI)] were 1.51 (1.13-2.03), 1.84(1.07-3.16) and 1.37 (1.11-1.69), respectively. The summary odd ratio of the eNOS (B/A) polymorphism in RPL was 1.15 (0.94-1.41), and failed to show significance at meta-analysis.

CONCLUSIONS

Meta-analyses of available data showed significant associations between the VEGF (-1154G>A), p53 (codon72) and eNOS (Glu298Asp) polymorphisms and idiopathic RPL. These angiogenesis- and vasoconstriction-related genes jointly confer higher susceptibility to idiopathic RPL.

Genetic analysis of eNOS gene polymorphisms in association with recurrent miscarriage among North Indian women

This study investigated the association of common polymorphisms of the endothelial nitric oxide synthase (eNOS) gene with recurrent miscarriage (RM) among North Indian women. A total of 200 patients with unexplained recurrent miscarriages and 300 controls were genotyped for six polymorphic regions of eNOS by PCR, re-sequencing and RFLP. The GG genotype of 12862A>G, the G allele of Glu298Asp and the aa genotype of intron 4VNTR increased the risk of RM by ∼1.8-fold, ∼3.5-fold and ∼2-fold, respectively (odds ratio (OR) 1.84, 95% confidence intervals (CI) 1.19-2.86, P=0.0066; OR 3.58, 95% CI 2.12-6.03, P<0.0001; and OR 2.23, 95% CI 1.04-4.77, P=0.0493). Two haplotypes were found to have a significant protective effect against RM (OR 0.63, 95% CI 0.48-0.82, P=0.0009; and OR 0.4, 95% CI 0.19-0.81, P=0.0149) and another was found to increase the risk of RM by ∼2-fold (OR 2.12, 95% CI 1.16-3.89 P=0.0195). In conclusion three common polymorphisms of eNOS gene, 12862A>G, Glu298Asp and intron 4VNTR increase the risk of RM in North Indian women. Risk of RM may also be modified by the presence of particular haplotypes.

Role of uterine artery Doppler velocimetry indices and plasma adrenomedullin level in women with unexplained recurrent pregnancy loss

AIM

To evaluate uterine artery Doppler flow resistance and plasma adrenomedullin levels in women with unexplained recurrent pregnancy loss (RPL) compared to controls.

MATERIAL & METHODS

Eighty-three women, who attend the department of Obstetrics and Gynecology, Benha University, Egypt, participated in this study (RPL group: n=40, and control group: n=43). Uterine artery Doppler and plasma adrenomedullin (AM) (pg/mL) levels were measured for all women in the mid-luteal phase of a non-pregnant cycle.

RESULTS

Both uterine artery pulsatility index (PI) and AM levels were significantly higher in RPL group compared to controls (2.71 ± 0.259 vs 2.06 ± 0.194 for PI and 287.5 ± 80.4 pg/mL vs 156.1 ± 39.8 pg/mL for AM, P<0.01). Uterine artery PI had a significant positive correlation with plasma AM levels both in the RPL group (r=0.645, P<0.001) and in the control group (r=0.384, P=0.011). Number of previous miscarriages in RPL group was significantly correlated with both uterine artery PI (r=0.838, P=0.015) and plasma AM levels (r=0.509, P=0.001).

CONCLUSIONS

Uterine artery PI may be useful in identifying women with unexplained RPL who have impaired uterine circulation. Plasma AM may serve as a biochemical marker for RPL caused by impaired uterine perfusion.

Correlation and Identification of Variable number of Tandem repeats of eNOS Gene in Coronary artery disease (CAD)

Endothelium-derived nitric oxide (NO) is synthesized from l-arginine by endothelial nitric oxide synthase (eNOS) encoded by the NOS3 gene on chromosome7. Since reduced NO synthesis has been implicated in the development of coronary atherosclerosis; polymorphisms of NOS gene might be associated with increased susceptibility to coronary artery disease (CAD). We therefore undertook this study to determine the association between the occurrence of CAD and eNOS4 b/a polymorphism in South Indian patients. We investigated the polymorphisms in the 27 base-pair tandem repeats in intron4 of the eNOS gene in 100 unrelated CAD patients with positive coronary angiograms and 100 age and sex matched control subjects without any history of symptomatic CAD. The eNOS gene intron4 b/a VNTR polymorphism was analyzed by polymerase chain reaction. The plasma lipids levels and other risk factors were also determined. The genotype frequencies for eNOS4b/b, eNOS4a/b and eNOS4a/a were 63, 26 and 11 per cent in CAD subjects, and 72, 20 and 8 per cent in control subjects, respectively. The genotype frequencies did not differ significantly between the two groups. The frequency of the a allele was 0.24 per cent in CAD subjects and 0.18 per cent in control subjects and no significant association was found between patients and control group (P = 0.57, Odds ratio = 3.62). Plasma lipids, glucose and creatinine levels were significantly increased in CAD group. The genotypic frequencies and the allele frequency did not differ significantly between the CAD patients and controls indicating that this polymorphism was not an independent risk factor for the development of CAD in South Indian patients.

Polymorphisms of the endothelial nitric oxide synthase gene in premenopausal women with polycystic ovary syndrome

OBJECTIVES

To investigate the association of two common genetic polymorphisms of the gene encoding for endothelial nitric oxide synthase (Nos3), the enzyme catalyzing the production of nitric oxide (NO), with occurrence of the polycystic ovary syndrome (PCOS).

METHODS

In a prospective case-control study, we analyzed 2 polymorphisms of the Nos3 gene cluster (Nos 3 exon 7 Glu298Asp and 27-base pair repeat in intron 4 of Nos3) in a series of 210 premenopausal Caucasian women with PCOS and 171 healthy controls using pyrosequencing and PCR, respectively. Women completed a detailed questionnaire and underwent a peripheral venous puncture, ultrasonography, and a standardized oral glucose tolerance test (OGTT).

RESULTS

Genotype frequencies were not significantly different among women with PCOS and controls for the exon 7Nos3 and the intron 4Nos3 polymorphism (p=0.3 and 0.2, respectively).

CONCLUSIONS

In our series, two common polymorphisms of the Nos3 gene cluster were not associated with occurrence of PCOS.

Lack of consistent association between endothelial nitric oxide synthase gene polymorphisms, homocysteine levels and recurrent pregnancy loss in tunisian women

PROBLEM

Polymorphisms of the endothelial nitric oxide synthase (eNOS) gene have been associated with reduced vascular NO production or increased level of homocysteine, and evaluated as risk factors for recurrent pregnancy loss (RPL). Therefore, in this case-control study, we aimed to determine the effects of some eNOS functional polymorphisms: the 27-bp intron 4 repeat, the 894G/T of exon 7, and the promoter substitution -786T/C, in women with RPL.

METHOD OF STUDY

We genotyped 350 patients with RPL and 200 healthy women by polymerase chain reaction (PCR) and restriction fragment length polymorphism-PCR (RFLP-PCR). The homocysteine total plasma concentrations (tHcy) were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

None of the eNOS polymorphisms-related alleles, genotypes, and haplotypes were associated with RPL. The tHcy were similar between patients and controls; no significant association between tHcy levels and eNOS genotypes could be evidenced.

CONCLUSION

The present study identified a lack of association between eNOS gene polymorphisms, the risk of RPL and tHcy levels.

Endothelial nitric oxide synthase gene polymorphisms in recurrent spontaneous abortions

OBJECTIVE

The risk of miscarriage is enhanced by a variety of genetic and environmental factors. Previous studies indicated an association between endothelial nitric oxide synthase (eNOS) activity, and implantation and maintenance of pregnancy, but it is rather controversial whether polymorphisms of the gene encoding for eNOS are associated with recurrent spontaneous abortions (RSA). The aim of our study was to determine whether the 27 bp intron 4 repeat polymorphism (4VNTR) and a Glu298Asp missense mutation encoded by exon 7 of the eNOS gene are associated with an increased risk for recurrent spontaneous abortions (RSA), in the Greek population.

METHODS

A total of 126 women who had at least three unexplained spontaneous abortions before 20 weeks of gestation, with the same partner, were included in the study group. The control group consistent of 130 women with at least two live childbirths and without history of abortions. All patients and controls were investigated for the two polymorphisms. To genotype the cohorts we used the PCR-RFLPs method.

RESULTS

The observed frequencies of bb, ba, aa genotypes of the VNTR, in intron 4, polymorphism were 0.75, 0.24, 0.01, respectively, for the patient group and 0.73, 0.24, 0.03, respectively, for the control group. The observed frequencies of GG, GT, TT of the Glu298Asp polymorphism were 0.42, 0.45, 0.13, respectively, for the patient group and 0.47, 0.45, 0.08, respectively, for the control group. Statistical analysis of the results indicates no significant difference between the two groups, for both the two studied polymorphisms.

CONCLUSION

Our results do not show any influence of the two polymorphisms, VNTR in intron 4 and Glu298Asp of the eNOS gene, on early pregnancy.

Maternal Endothelial Nitric Oxide Synthase Genotype Influences Offspring Blood Pressure and Activity in Mice

Deficiencies in maternal endothelial NO synthase (eNOS) have been associated with pregnancy complications, intrauterine growth retardation, and altered vascular function in offspring. In the present study, we investigated the influence of the maternal eNOS genotype on offspring's blood pressure, heart rate, and locomotor activity. The effect of maternal eNOS genotype was made by comparing telemetered blood pressure and activity between 2 groups of 13- to 16-week-old male heterozygous eNOS knockout mice, 1 produced by a cross of eNOS knockout (eNOS-/-) mothers and wild-type (eNOS+/+) fathers (eNOS(+/-MAT) offspring, N=11), the other by a cross of eNOS+/+ mothers and eNOS-/- fathers (eNOS(+/-PAT) offspring, N=10). Data were also collected for homozygous eNOS-/- and eNOS+/+ mice (N=15 each). Heterozygous eNOS knockout mice exhibited blood pressures that were intermediate to the eNOS+/+ and eNOS-/- groups. Relative to eNOS(+/-PAT) mice, eNOS(+/-MAT) mice exhibited significant increases in nocturnal diastolic arterial pressure and diurnal variations (dark-light difference) in systolic, mean, and diastolic arterial pressure. In addition, indices of spontaneous nocturnal locomotor activity, including both the proportion of time spent active and the intensity of activity when active, were also significantly increased. Heart rate did not differ between the groups. Our results suggest that the maternal eNOS genotype influences both blood pressure and behavior of offspring, possibly as a consequence of developmental programming associated with intrauterine growth retardation.