An A > G polymorphism at position -670 in the Fas (TNFRSF6) gene in pregnant women with pre-eclampsia and intrauterine growth restriction

FAS gene polymorphisms (rs3740286 and rs4064) were not associated with pre-eclampsia risk

Pre-eclampsia results in real risk and significant impact on indicators related to maternal and child health. The only known treatment is delivery of the fetus and placenta. Despite intensive research, the causes of PE remain to be elucidated. It is suggested that pre-eclampsia is caused by a global maternal inflammatory response to a damaged placenta. Besides inflammation, cytotoxic and apoptotic mechanisms are also implicated in the pathogenesis of pre-eclampsia. Considering the importance of apoptosis to pre-eclampsia genesis, the aim of this study was to determine the frequencies of the genotypes for FAS gene polymorphisms (rs3740286 and rs4064) and to associate these with pre-eclampsia development. Women with and without pre-eclampsia were investigated. Accordingly, peripheral blood was collected, and DNA extracted, followed by genotyping using Real-time PCR with hydrolysis probe. The results showed no association between genotypes and pre-eclampsia development for both polymorphisms studied (χ2=3.39; p=.177, for rs3740286 and χ2=0.119; p=.94 for rs4064). Women with familiar history of pre-eclampsia and primiparity showed more probability to develop the condition, by multiple logistic regression analysis (OR=8.61, CI=3.39-21.86, p<0.0001; OR=6.64. CI=2.94-14.99, p<0.0001, respectively). It seems that FAS gene polymorphisms (rs3740286 and rs4064) might not be important candidates for the development of pre-eclampsia.

The relationship between Fas and Fas ligand gene polymorphism and preeclampsia risk

Preeclampsia is an idiopathic multisystem disorder with partial genetic and immunological etiology. Several studies investigated the association between various single-nucleotide polymorphisms (SNPs) in Fas and Fas ligand (FasL) genes and the risk of preeclampsia. However, they achieved inconsistent results. Therefore, we conducted a meta-analysis by systematically searching the Cochrane Library, PubMed and Embase databases and assessed this association by calculating pooled odds ratios with 95% confidence interval to reach a more trustworthy conclusion. Subgroup analyses by genotype methods and source of controls (SOC) were also conducted. Seven citations containing nine studies were included for four SNPs (Fas -670 A/G, FasL 124A/G, FasL -844C/T, Fas -1377 G/A) in this meta-analysis. Our data suggested the G allele and genotype GG of the Fas -670 A/G polymorphism, GG genotype of the FasL 124A/G polymorphism, and TT genotype of the FasL -844C/T polymorphism increased the risk of preeclampsia. Stratification analyses by genotype methods and SOC also indicated that Fas -670 A/G polymorphism was related to increased risk for preeclampsia. In conclusion, Fas and FasL gene polymorphisms play important roles in the development of preeclampsia. Further well-designed studies in other races are needed to confirm the findings of this meta-analysis.

FAS A-670G and Fas ligand IVS2nt A 124G polymorphisms are significantly increased in women with pre-eclampsia and may contribute to HELLP syndrome: a case-controlled study

OBJECTIVE

We evaluated the association between the Fas-670A/G and the Fas ligand FasL IVS2nt 124 A/G polymorphisms and the risk of pre-eclampsia and its complications.

DESIGN

A case-controlled study.

SETTING

University Hospitals in most areas of Tunisia.

POPULATION

We recruited 300 pregnant women who developed pre-eclampsia and 300 age-matched healthy pregnant women from the same hospital.

METHODS

Genotyping of Fas-670A/G and the FasL IVS2nt 124A/G gene polymorphisms were conducted using polymerase chain reaction-restriction fragment length polymorphism among our cohort.

MAIN OUTCOME MEASURES

Fisher's exact test was used to compare the statistical differences between groups for categorical variables and Student t tests were used for continuous variables.

RESULTS

The frequency of the Fas-670G gene variant was significantly increased in women with pre-eclampsia (42%) compared with control women (30%; P < 0.001). Also, a statistically significant difference was obtained in the distribution of the FasL IVS2nt 124G gene variant when comparing women with pre-eclampsia (43%) with controls (30%; P < 0.001). Interestingly, we found that the carriage of Fas-670G was associated with increased liver enzymes, suggesting an increased prevalence of the haemolysis, elevated liver enzymes and low platelets (HELLP) syndrome, a pre-eclampsia complication.

CONCLUSION

The Fas-670G and FasL IVS2nt 124G polymorphisms are associated with a higher risk of pre-eclampsia and its complications.

TWEETABLE ABSTRACT

Polymorphisms in the Fas and FasL genes are associated with increased risk of pre-eclampsia and HELLP syndrome.

Fas and FasL genetic polymorphisms in women with recurrent pregnancy loss: a case-control study

Aberrant apoptosis at the trophoblast-maternal interface and abnormal expression of Fas and Fas ligand (FasL) have been reported in complicated pregnancies with recurrent pregnancy losses (RPL) and preeclampsia. We assessed the prevalence of Fas and FasL genetic polymorphisms in Korean women with RPL and in fertile controls. In total, 306 women with RPL and 298 fertile controls were enrolled. Genotype distributions of Fas and FasL in RPL patients versus fertile controls were examined under the Hardy-Weinberg equilibrium. Fas -670 A/G genotype (AA versus AG versus GG, p = 0.340) and allele frequencies (A versus G, p = 0.412) were not different between the RPL and control groups. There was no difference in each Fas -1377 G/A and FasL -844 C/T genotype, and their allele frequencies. In addition, the unions of two zygosities of each genotype and their combined genotypes did not differ between two groups. No difference in the prevalence of Fas and FasL single-nucleotide polymorphisms (SNPs) was observed between women with RPL and fertile controls among Korean women. To determine the possibility of genetic polymorphisms in Fas and its ligand as risk factors for RPL, further studies in various races and a large study population are needed.

First trimester screening of circulating C19MC microRNAs can predict subsequent onset of gestational hypertension

OBJECTIVE

The objective of the study was to evaluate risk assessment for gestational hypertension based on the profile of circulating placental specific C19MC microRNAs in early pregnancy.

STUDY DESIGN

The prospective longitudinal cohort study of women enrolled at first trimester screening at 10 to 13 weeks was carried out (n = 267). Relative quantification of placental specific C19MC microRNAs (miR-516-5p, miR-517*, miR-518b, miR-520a*, miR-520h, miR-525 and miR-526a) was determined in 28 normal pregnancies and 18 pregnancies which developed gestational hypertension using real-time PCR and a comparative Ct method relative to synthetic C. elegans microRNA (cel-miR-39).

RESULTS

Increased extracellular C19MC microRNA plasmatic levels (miR-516-5p, p<0.001; miR-517*, p = 0.007; miR-520h, p<0.001; miR-518b, p = 0.002) were detected in patients destined to develop gestational hypertension. MiR-520h had the best predictive performance with a PPV of 84.6% at a 7.1% false positive rate. The combination of miR-520h and miR-518b was able to predict 82.6% of women at the same false positive rate. The overall predictive capacity of single miR-518b (73.3% at 14.3% FPR), miR-516-5p (70.6% at 17.9% FPR) and miR-517* (57.9% at 28.6% FPR) biomarkers was lower.

CONCLUSION

The study brought interesting finding that the up-regulation of miR-516-5p, miR-517*, miR-520h and miR-518b is associated with a risk of later development of gestational hypertension. First trimester screening of extracellular miR-520h alone or in combination with miR-518b identified a significant proportion of women with subsequent gestational hypertension.

Are placental Fas and Fas ligand gene polymorphisms associated with preeclampsia?

OBJECTIVE

Increased placental trophoblastic apoptosis has been reported in pregnancies complicated by preeclampsia. Fas-Fas ligand is one of the major signal transduction pathways of apoptosis. The objective of this study was to determine if placental Fas and Fas ligand gene polymorphisms differ between patients with and without preeclampsia.

STUDY DESIGN

Forty-five singleton placentas were studied. Twenty-three placentas were from preeclamptic pregnancies and 22 were from normotensive controls. Genotyping was performed for Fas-1377, Fas-691, Fas-670, Fas ligand-844, Fas ligand-1174, Fas ligand-2777. Chi-square and Fisher's exact tests were used for statistical analysis.

RESULTS

There were no significant differences in maternal age, parity or race between the two groups. There were no significant differences in genotypes or allele frequencies for the Fas-1377, Fas-691, Fas-670, Fas ligand-844, Fas ligand-1174 and Fas ligand-2777.

CONCLUSION

Immune intolerance of maternal and placental interaction plays an important role in the pathogenesis of preeclampsia. Our findings do not support the role of placental Fas and Fas ligand gene polymorphisms in the pathogenesis of preeclampsia.

Association of FAS -1377 G>A and FAS -670 A>G functional polymorphisms of FAS gene of cell death pathway with recurrent early pregnancy loss risk

Apoptosis during the early stages of pregnancy enables the remodeling of the uterus for proper placentation. Apoptosis in the maternal activated cytotoxic T lymphocytes allows maternal immune tolerance to pregnancy and in glandular and stromal cells it helps with trophoblastic endometrial invasion. FAS gene is expressed at the maternal-fetal interface and is involved in the regulation of immune response and implantation. Altered FAS expression may result in altered apoptosis and ultimately affects both immune response and implantation. FAS -1377 G>A and FAS -670 A>G functional polymorphisms in the promoter region of FAS gene modulate its expression at transcriptional level. In a case-control study the contribution of FAS -1377 G>A and FAS -670 A>G polymorphisms to the risk of recurrent early pregnancy loss (REPL) was evaluated. DNA from 134 cases with a history of three or more REPL and 124 healthy controls with successful pregnancy outcomes were genotyped through PCR-RFLP. DNA sequencing was used to ascertain PCR-RFLP results. The genotype and allele frequencies for FAS -1377 G>A and FAS -670 A>G polymorphisms were compared in REPL and controls. FAS -1377 AA and AG genotypes were associated with an increased risk of REPL (OR, 3.25; 95%CI, 1.52-6.98 and OR, 2.62; 95%CI, 1.48-4.64, respectively), whereas FAS -670 genotypes conferred no risk. The -1377 AA/-670 GG genotypes combination of FAS polymorphisms showed highest risk (OR, 8.15; 95%CI, 2.75-25.81). Genotype combinations -1377 GA/-670 AA and -1377 GA/-670 AG were also statistically significant, suggestive of their role in REPL risk.

Polymorphisms in maternal and fetal genes encoding for proteins involved in extracellular matrix metabolism alter the risk for small-for-gestational-age

OBJECTIVE

To examine the association between maternal and fetal genetic variants and small-for-gestational-age (SGA).

METHODS

A case-control study was conducted in patients with SGA neonates (530 maternal and 436 fetal) and controls (599 maternal and 628 fetal); 190 candidate genes and 775 SNPs were studied. Single-locus, multi-locus and haplotype association analyses were performed on maternal and fetal data with logistic regression, multifactor dimensionality reduction (MDR) analysis, and haplotype-based association with 2 and 3 marker sliding windows, respectively. Ingenuity pathway analysis (IPA) software was used to assess pathways that associate with SGA.

RESULTS

The most significant single-locus association in maternal data was with a SNP in tissue inhibitor of metalloproteinase 2 (TIMP2) (rs2277698 OR = 1.71, 95% CI [1.26-2.32], p = 0.0006) while in the fetus it was with a SNP in fibronectin 1 isoform 3 preproprotein (FN1) (rs3796123, OR = 1.46, 95% CI [1.20-1.78], p = 0.0001). Both SNPs were adjusted for potential confounders (maternal body mass index and fetal sex). Haplotype analyses resulted in associations in α 1 type I collagen preproprotein (COL1A1, rs1007086-rs2141279-rs17639446, global p = 0.006) in mothers and FN1 (rs2304573-rs1250204-rs1250215, global p = 0.045) in fetuses. Multi-locus analyses with MDR identified a two SNP model with maternal variants collagen type V α 2 (COL5A2) and plasminogen activator urokinase (PLAU) predicting SGA outcome correctly 59% of the time (p = 0.035).

CONCLUSIONS

Genetic variants in extracellular matrix-related genes showed significant single-locus association with SGA. These data are consistent with other studies that have observed elevated circulating fibronectin concentrations in association with increased risk of SGA. The present study supports the hypothesis that DNA variants can partially explain the risk of SGA in a cohort of Hispanic women.

A single-nucleotide polymorphism (-670) of the maternal Fas gene is associated with intrauterine growth restriction

OBJECTIVE

We sought to determine whether the Fas (-670) single-nucleotide polymorphism is associated with intrauterine growth restriction.

STUDY DESIGN

Twenty-seven pregnant women with intrauterine growth restriction in the absence of preeclampsia and 50 pregnant women with uncomplicated pregnancies were studied. DNA was extracted from maternal and infant buccal smears and allelic discrimination was performed for Fas (-670). Student t test, chi2, and z tests were used.

RESULTS

There were no differences in maternal age, race, or parity between the intrauterine growth restriction and control patients. Mothers of intrauterine growth restriction infants had a significantly different genotype distribution for this single nucleotide polymorphism, and for the ratio of GG genotype (GG, AA: 0.41, 0.18 maternal intrauterine growth restriction; 0.14, 0.32 controls; respectively, P=.03). These genotype differences were significantly different in white, but not black mothers with intrauterine growth restriction (P=.03, and .3; respectively). In contrast, no differences were found in infants' Fas (-670) single-nucleotide polymorphism genotypes.

CONCLUSION

This study demonstrates an association between the maternal Fas (-670) single-nucleotide polymorphism and the development of intrauterine growth restriction.

Polymorphisms of FAS and FAS ligand genes in preeclamptic women

OBJECTIVES

This study investigated the influence that Fas and Fas ligand gene polymorphisms might have on preeclampsia. The pathogenesis of preeclampsia is still enigmatic and several studies have proposed that it may, in part, be determined by genetic susceptibility. Therefore, the identification of a gene polymorphism associated with an increased risk of preeclampsia might well represent a useful tool in the identification of at risk pregnant women enabling the setup of preventive therapy. Apoptosis has also been implied in the pathogenesis of preeclampsia and since Fas and Fas ligand are the main apoptotic pathway members, they may represent candidate genes involved in the development of preeclampsia. A polymorphism at the 670 position (A-G) in the Fas gene has been found more frequently in Hungarian women with preeclampsia.

STUDY DESIGN

The study cohort was a group of 50 women with preeclampsia and 142 healthy control subjects from the general Italian population. They were studied, by RFLP analysis, to validate the role that the 670 G Fas gene polymorphism plays in preeclampsia, and to evaluate the Fas ligand IVS2nt 124 G polymorphism. The Fisher's exact test was used to compute the statistical difference between groups.

RESULTS

The presence of the 670 G Fas gene variant was observed in 42 preeclamptic patients (84%) and 96 members of the general population control group (67.6%) (p=0.029). Regarding the Fas ligand gene, the IVS2nt 124 G variant was present in 14 preeclamptic patients (28%) and in 47 of the general population control subjects (33.1%) (p=0.6).

CONCLUSIONS

The present study validated the hypothesis that the Fas 670 G variant may have an influencing role in preeclampsia.

Genomics for health in preconception and prenatal periods

PURPOSE

To review and report changes in genomic-based knowledge and care during the preconception and prenatal periods.

DESIGN

Integrative review of relevant medical and nursing literature.

FINDINGS

Client education and counseling are needed to understand genomic information and provide guidance in interpreting this information and making decisions. The factors that influence decision-making about testing and acting on test results constitute a complex process that has not been well studied. Family history is an important tool for obtaining genomic information and can assist women and families in understanding risk preconceptionally and prenatally. Genomic research has enhanced understanding of the mechanisms of birth defects such as neural tube defect and will likely provide research opportunities to better understand complex perinatal outcomes such as preterm birth.

CONCLUSIONS

Research, education, advocacy, and anticipatory guidance are needed as women and families obtain more genetic and genomic information before and during pregnancy. All nurses will be involved in helping patients use genetic and genomic information to understand risk and to develop strategies to modify risk, and in translating the expanding array of genomic information to improve birth outcomes.

Invasive trophoblasts stimulate vascular smooth muscle cell apoptosis by a fas ligand-dependent mechanism

During pregnancy, trophoblasts migrate from the placenta into uterine spiral arteries, transforming them into wide channels that lack vasoconstrictive properties. In pathological pregnancies, this process is incomplete. To define the fundamental events involved in spiral artery remodeling, we have studied the effect of trophoblasts on vascular smooth muscle cells (SMCs). Here we demonstrate for the first time that apoptosis of SMCs can be initiated by invading trophoblasts. When trophoblasts isolated from normal placenta (primary trophoblasts) or conditioned medium was perfused into spiral or umbilical artery segments, apoptosis of SMCs resulted. Culture of human aortic SMCs (HASMCs) with primary trophoblasts, primary trophoblast-conditioned medium, or a trophoblast-derived cell line (SGHPL-4) also significantly increased SMC apoptosis. Fas is expressed by spiral artery SMCs, and a Fas-activating antibody triggered HASMC apoptosis. Furthermore, a Fas ligand (FasL)-blocking antibody significantly inhibited HASMC apoptosis induced by primary trophoblasts, SGHPL-4, or trophoblast-conditioned medium. Depleting primary trophoblast-conditioned medium of FasL also abrogated SMC apoptosis in vessels in situ. These results suggest that apoptosis triggered by the release of soluble FasL from invading trophoblasts contributes to the loss of smooth muscle from the walls of spiral arteries during pregnancy.

Searching for genetic clues to the causes of pre-eclampsia

Pre-eclampsia and its related syndromes are significant causes of maternal and fetal death, but much remains unclear about the underlying disease mechanisms. Epidemiological research has consistently demonstrated a familial predisposition to pre-eclampsia, which has encouraged genetic research in this area. The goal is the discovery of susceptibility genes which will inform understanding of the pathophysiology of pre-eclampsia, and may prove to be targets for therapeutic or preventative strategies. This review examines the application of molecular technologies to the search for genetic clues in pre-eclampsia and emphasizes the importance of integrative approaches. The results of recent genome-wide linkage studies have been particularly encouraging, identifying a number of loci which merit closer examination. Candidate gene studies have proved less fruitful, generating conflicting and inconclusive results. Possible explanations and remedies for this deficiency are discussed with a view to stimulating closer collaboration between researchers in this field.

Fas (TNFRSF6) Gene Polymorphism in Pregnant Women With Hemolysis, Elevated Liver Enzymes, and Low Platelets and in Their Neonates

OBJECTIVE

To estimate whether an A>G polymorphism at position -670 in the gene coding for Fas (gene symbol TNFRSF6) is associated with hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome.

METHODS

In a retrospective study, buccal swabs from 81 women with the complete form of HELLP syndrome and 83 normotensive control women with uncomplicated full-term pregnancy, and 110 of their neonates, were analyzed for the presence of the TNFRSF6-670 polymorphism. Investigators were blinded to clinical outcomes.

RESULTS

Pregnant women heterozygous for the TNFRSF6-670 genotype were more likely than those homozygous for TNFRSF6-670*A allele to have HELLP syndrome (P = .01; odds ratio 2.7, 95% confidence interval 1.2-5.9). Moreover, patients with homozygous carriage of the TNFRSF6-670*G allele were more likely than those homozygous for the wild type of the Fas gene (TNFRSF6-670*A/A) to have HELLP syndrome (P = .006; odds ratio 4.0, 95% confidence interval 1.7-9.8). In contrast, TNFRSF6-670 genotype distribution of neonates born to mothers with HELLP syndrome was not statistically different from that found in neonates born to healthy pregnant women (P = .4). In patients with HELLP syndrome, no association between TNFRSF6 genotype distribution and severity of hemolysis, platelet counts or liver enzymes levels was noted.

CONCLUSION

A single A>G nucleotide substitution at position -670 in the maternal but not neonatal TNFRSF6 gene coding for Fas is associated with a higher risk for HELLP syndrome.

LEVEL OF EVIDENCE

II-2.