The 4G/5G polymorphism of the plasminogen activator inhibitor-1 gene is associated with severe preeclampsia

A Rare Case of Pulmonary Embolism, Deep Vein Thrombosis, Bilateral Avascular Necrosis of the Femoral Head, and Miscarriage following COVID-19 in a Patient with Multiple Genetic Coagulation Factor Deficiency-A Case Report

The coronavirus disease (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The most common symptoms of COVID-19 are respiratory symptoms, but some patients develop severe thrombotic complications. Studies have looked into the association between the disease severity in COVID-19 patients and polymorphisms in the genes encoding prothrombotic and cardiovascular risk factors. The presented rare case describes inflammatory and acute thrombotic complications with musculoskeletal involvement in a patient with combined coagulation genetic defects. A 37-year-old woman was hospitalized with a respiratory infection of coronavirus etiology complicated by pneumonia and pulmonary embolism and confirmed using computed tomography and elevated D-dimer. Sixteen days after discharge, she developed deep vein thrombosis after discontinuation of antiplatelet and anticoagulant therapy due to bleeding. Four months after infection, we found bilateral avascular necrosis of the femoral head. The patient had a miscarriage with considerable blood loss and was given genetic testing, which confirmed the presence of a combined defect with a risk of both thrombosis and bleeding-heterozygous for the Leiden G1691A mutation, homozygous for the 677C>T mutation (MTHFR), heterozygous for the Val34Leu (factor XIII) mutation, and 4G/5G polymorphism in the promoter of the plasminogen activator inhibitor 1 (PAI-1) genes. The described rare clinical case poses a serious challenge regarding the anticoagulant and antiplatelet therapy, especially in the presence of thrombotic complications in COVID-19 and the underlying genetic defect associated with a risk of bleeding, including life-threatening intracranial bleeding. More research is needed to better understand the major medical concern about antithrombotic treatment in COVID-19 patients with bleeding risk in the context of genetic coagulation disorders. The case raises the vigilance of clinicians to search for a genetic predisposition to the development of severe thrombotic events in COVID-19 patients with no other known underlying diseases.

Association of single nucleotide polymorphisms (4G/5G) of plasminogen activator inhibitor-1 and the risk factors for placenta-related obstetric complications

BACKGROUND

Placenta-related obstetric complications (PROCs) such as miscarriage, fetal growth restriction, preeclampsia, and preterm birth are the major causes of maternal and fetal morbidity and mortality. The objective of this study was to search the relevance of plasminogen activator inhibitor-1 (PAI-1) polymorphisms and co-morbidities and the risk factors for PROCs such as miscarriage, fetal growth restriction, preeclampsia, and preterm birth.

METHOD

This retrospective study analyzed the PAI-1 genotype in a cohort of 268 multiparous women with poor obstetric history. Poor obstetric history was defined as the presence of at least one of the PROCs and/or poor gestational outcomes at the previous pregnancy/pregnancies.

RESULTS

5G allele frequency was higher than the 4G allele frequency in the cohort (0.767 vs. 0.233). The frequencies of having at least one risk factor are relatively similar among the different PAI-1 genotypes ( P  > 0.05). However, the presence of MTHFR polymorphisms (homozygous and compound heterozygous forms of C677T and A1298G) and hereditary thrombophilia (Factor V Leiden and prothrombin G20210A gene mutations, and FXIII deficiency) were found to be associated with PAI 4G/4G ( P  = 0.048) and 5G/5G ( P  = 0.022) genotypes, respectively. Significant differences were not observed in other risk factors and co-morbidities such as autoimmune disorders, chronic inflammatory diseases, history of venous thromboembolism, carbohydrate metabolism disorders, hyperlipidemia, cardiovascular and cerebrovascular diseases depending on PAI-1 genotypes ( P  > 0.05).

CONCLUSION

MTHFR polymorphisms were found to be associated with PAI 4G/4G genotype, while 5G/5G genotype was observed more frequently in hereditary thrombophilia cases.

The Role of Plasminogen Activator Inhibitor Type 1 (PAI-1) in Placenta-Mediated Pregnancy Complications: A Systematic Review

Plasminogen activator inhibitor type 1 (PAI-1) is a main inhibitor of fibrinolysis. The PAI-1 gene (SERPINE1) harbors genetic variants with the potential of modifying plasma levels of PAI-1. A delicate balance exists between the coagulation and fibrinolytic system, and changes in PAI-1 have been suggested to compromise establishment of a successful pregnancy. Therefore, this systematic review investigated the association between genetic variants and/or plasma levels of PAI-1 and placenta-mediated pregnancy complications. An extensive literature search was conducted in PubMed, Embase, and Web of Science on the 29^th of April 2021. All studies underwent quality rating according to The Study Quality Assessment Tools checklist provided by National Heart, Lung and Blood Institute. A total of 71 studies were included, among which 60 studies investigated PAI-1 genotypes and 11 studies measured PAI-1 plasma levels. In 32 out of 59 studies, no association was found between the PAI-1 4G/5G polymorphism (rs1799768) and placenta-mediated pregnancy complications, which was stated as no significant difference in the genotype distribution comparing women with and without placenta-mediated pregnancy complications or no significantly increased odds of placenta-mediated pregnancy complications carrying the 4G/4G or 4G/5G genotype. Eight out of 11 studies reported significantly higher PAI-1 plasma levels in preeclamptic women than in women without preeclampsia. In conclusion, no clear evidence indicates that PAI-1 polymorphisms are associated with placenta-mediated pregnancy complications, and the possible association between high PAI-1 plasma levels and preeclampsia needs further investigations. Thus, investigation of PAI-1 genotypes and PAI-1 plasma levels does not currently seem to have a place in daily clinical practice managing placenta-mediated pregnancy complications.

Association of Plasminogen Activator Inhibitor-1 Gene Polymorphisms and Methylene Tetrahydrofolate Reductase Polymorphisms with Spontaneous Miscarriages

AIM

The objective of this study was to investigate a possible correlation between the plasminogen activator inhibitor-1 (PAI-1) and methylene tetrahydrofolate reductase (MTHFR) polymorphisms and unexplained spontaneous miscarriages (SM).

MATERIALS AND METHODS

PAI-1 polymorphisms were evaluated in 150 women with pregnancy in their history. One hundred women with a history of SM formed the study group and 50 women with normal pregnancies served as the control group. Also, the combination of PAI-1 and MTHFR polymorphisms were evaluated in 138 women out of a total of 150, which included 92 women with SM in their history compared to 46 women in the control group. For statistical analysis, χ2 test, Phi, and Cramer V tests were used; p < 0.05 was taken as a statistically significant result.

RESULTS

Our findings show: (a) the correlation between SM and PAI-1 mutations reaches statistical significance (p = 0.026); (b) there was a statistically significant difference between heterozygous PAI-1 in women with only 1 SM compared to the control group (p = 0.047); (c) the comparison of combinations of both mutations, PAI-1 and MTHFR, with the control group demonstrates statistical significance in favor of women with SM and both mutations (p = 0.022).

CONCLUSION

PAI-1 and MTHFR polymorphisms may play an important role in pregnancy complications because heterozygous PAI-1 mutations and a combination of both PAI-1 and MTHFR mutations might contribute to SM.

Plasminogen Activator Inhibitor-1 4G/5G Polymorphism is Associated with Reproductive Failure: Metabolic, Hormonal, and Immune Profiles

PROBLEM

Association between PAI-1 4G/5G polymorphism and reproductive failures has been postulated. We aimed to investigate its impact on metabolic, hormonal, and immune profiles of women with reproductive failures.

METHOD OF STUDY

A retrospective study was carried out in 208 women with a history of reproductive failure. Study patients were divided into three groups: women with repeated implantation failure (RIF, n = 40), recurrent pregnancy loss (RPL, n = 113), and both RIF and RPL (n = 55). Fertile controls were 92.

RESULTS

PAI-1 4G/4G was prevalent in RPL, RIF, and RIF/RPL groups when compared with controls (P = 0.003) and associated with increased risks of RIF, RPL, and RIF with RPL (OR = 4.5, 2.2 and 2.7). Women with PAI-1 4G/4G have significantly higher BMI, glucose, and PAI-1 levels and lower NK cytotoxicity when compared with women without PAI-1 4G/4G.

CONCLUSION

PAI-1 4G/5G polymorphism plays a major role in the pathogenesis of RPL and RIF by altering metabolic and immunological profiles.

Association of plasminogen activator inhibitor-type 1 (-675 4G/5G) polymorphism with pre-eclampsia: systematic review

BACKGROUND AND AIMS

Excessive generation of plasminogen activator inhibitor-type 1 (PAI-1) is implicated in the pathogenesis of pre-eclampsia and related conditions. The PAI-1 (-675 4G/5G) promoter polymorphism (rs1799889) affects transcriptional activity and is a putative genetic risk factor for pre-eclampsia. The aim of this study was identify, appraise and synthesise the available evidence for the association of the PAI-1 (-675 4G/5G) polymorphism with pre-eclampsia.

METHODS

Systematic review and random effects meta-analysis of genetic association studies.

RESULTS

We found 12 eligible genetic association studies in which a total of 1511 women with pre-eclampsia, eclampsia or HELLP syndrome and 3492 controls participated. The studies were generally small (median number of cases 102, range 24 to 403) and underpowered to detect plausible association sizes. Meta-analysis of all of the studies detected statistically significant gene-disease associations in the recessive [pooled odds ratio 1.28 (95% confidence interval 1.09, 1.50); population attributable risk 7.7%] and dominant [pooled odds ratio 1.21 (95% confidence interval 1.01, 1.44); population attributable risk 13.7%] models. We did not find evidence of statistical heterogeneity, funnel plot asymmetry or small study bias.

CONCLUSIONS

These data suggest that the fibrinolytic pathway regulated by the PAI-1 gene may contribute to the pathogenesis of pre-eclampsia and related conditions. This association, if confirmed in larger genetic association studies, may inform research efforts to develop novel interventions or help to prioritise therapeutic targets that merit evaluation in randomised clinical trials.

Association between the SERPINE1 (PAI-1) 4G/5G insertion/deletion promoter polymorphism (rs1799889) and pre-eclampsia: a systematic review and meta-analysis

The SERPINE1 -675 4G/5G promoter region insertion/deletion polymorphism (rs1799889) has been implicated in the pathogenesis of pre-eclampsia (PE), but the genetic association has been inconsistently replicated. To derive a more precise estimate of the association, a systematic review and meta-analysis was conducted. This study conformed to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed (MEDLINE), Scopus and HuGE Literature Finder literature databases were systematically searched for relevant studies. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for the allelic comparison (4G versus 5G) and genotypic comparisons following the co-dominant (4G/4G versus 5G/5G and 4G/5G versus 5G/5G), dominant (4G/4G+4G/5G versus 5G/5G) and recessive (4G/4G versus 4G/5G+5G/5G) genetic models. Between-study heterogeneity was quantified by I(2) statistics and publication bias was appraised with funnel plots. Sensitivity analysis was conducted to evaluate the robustness of meta-analysis findings. Meta-analysis of 11 studies involving 1297 PE cases and 1791 controls found a significant association between the SERPINE1 -675 4G/5G polymorphism and PE for the recessive genetic model (OR = 1.36, 95% CI: 1.13-1.64, P = 0.001), a robust finding according to sensitivity analysis. A low level of between-study heterogeneity was detected (I(2) = 20%) in this comparison, which may be explained by ethnic differences. Funnel plot inspection did not reveal evidence of publication bias. In conclusion, this study provides a comprehensive examination of the available literature on the association between SERPINE1 -675 4G/5G and PE. Meta-analysis results support this polymorphism as a likely susceptibility variant for PE.

Pathogenesis of preeclampsia: the genetic component

Preeclampsia (PE) is one of the main causes of maternal and fetal morbidity and mortality in the world, causing nearly 40% of births delivered before 35 weeks of gestation. PE begins with inadequate trophoblast invasion early in pregnancy, which produces an increase in oxidative stress contributing to the development of systemic endothelial dysfunction in the later phases of the disease, leading to the characteristic clinical manifestation of PE. Numerous methods have been used to predict the onset of PE with different degrees of efficiency. These methods have used fetal/placental and maternal markers in different stages of pregnancy. From an epidemiological point of view, many studies have shown that PE is a disease with a strong familiar predisposition, which also varies according to geographical, socioeconomic, and racial features, and this information can be used in the prediction process. Large amounts of research have shown a genetic association with a multifactorial polygenic inheritance in the development of this disease. Many biological candidate genes and polymorphisms have been examined in their relation with PE. We will discuss the most important of them, grouped by the different pathogenic mechanisms involved in PE.

Angiotensin-converting enzyme D/I and plasminogen activator inhibitor-1 4G/5G gene polymorphisms are associated with increased risk of spontaneous abortions in polycystic ovarian syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a main cause of infertility, particularly in high-risk settings such as spontaneous abortions (SAB). We aimed to evaluate the effect of genetic polymorphisms in ACE and plasminogen activator inhibitor-1 (PAI-1) on the occurrence of SAB in PCOS.

METHODS

One hundred and forty-two PCOS patients (83 women have a history of one or more unexplained SAB, 59 women have successfully live births) and 107 healthy controls matched for age and body mass index were included in the study. Levels of PAI-1, LH, FSH, testosterone, fasting glucose and insulin were measured. ACE deletion (D)/insertion (I) and PAI-1 4G/5G gene polymorphisms were performed.

RESULTS

The D/D and/or 4G/4G genotype frequency, the D or 4G allelic frequency, the combination of the ACE D/D and PAI-1 4G/5G, D/I and 4G/4G genotypes of PCOS patients with SAB women were statistically higher than non-SAB group (p<0.05). The 4G/4G or D/D genotype of PCOS with SAB patients had significantly higher PAI-1 levels than non-SAB women.

CONCLUSIONS

The ACE D/I and PAI-1 4G/5G gene polymorphisms might represent risk factor in PCOS with SAB. Homozygosity for ACE D or PAI-1 4G polymorphisms as well as compound carrier status are significant positive explanatory variable for PCOS patients with SAB, which may result in increased PAI-1 concentrations and hypofibrinolysis and contribute to early pregnancy loss.

4G/5G variant of plasminogen activator inhibitor-1 gene and severe pregnancy-induced hypertension: subgroup analyses of variants of angiotensinogen and endothelial nitric oxide synthase

Background

Pregnancy-induced hypertension (PIH) is a common cause of perinatal mortality. It is believed to result from the interaction of several factors, including those related to the blood coagulation system. We performed genotyping and subgroup analyses to determine if the 4G/5G genotypes of the plasminogen activator inhibitor-1 gene (PAI-1) play a role in the pathogenesis of PIH, and to evaluate possible interactions of the PAI-1 polymorphisms with those of the angiotensinogen gene (AGT) and the endothelial nitric oxide synthase gene (NOS3).

Methods

An association study of PAI-1 polymorphism, and subgroup analyses of common variants of AGT and NOS3, among 128 patients with PIH and 376 healthy pregnant controls.

Results

No significant differences were found between the cases and controls in the frequencies of allele 4G or the 4G/4G genotype. In subgroup analyses, after adjustment for multiple comparison, a significant association with the AGT TT genotype was found among women with the PAI-1 4G/4G genotype, and an association with the NOS3 GA+AA genotype was found among women with the 5G/5G or 4G/5G genotypes.

Conclusions

Our findings suggest that there are at least 2 pathways in the pathogenesis of severe PIH. However, with respect to early prediction and prevention of severe PIH, although the PAI-1 4G/4G genotype alone was not a risk factor for severe PIH, the fact that PAI-1 genotypes are associated with varying risks for severe PIH suggests that PAI-1 genotyping of pregnant women, in combination with other tests, may be useful in the development of individualized measures that may prevent severe PIH.

Angiogenesis inhibition causes hypertension and placental dysfunction in a rat model of preeclampsia

BACKGROUND

Preeclampsia is a serious pregnancy complication, accompanied by increased maternal and fetal morbidity. Different models have been used to study preeclampsia, but none of these display all the key features of the disease.

METHOD

We investigated the effects on maternal blood pressure and fetal outcome exerted by the angiogenesis inhibitor Suramin (100 mg/kg i.p.) during early placentation. Blood pressure and heart rate were measured continuously with telemetry in Sprague-Dawley rats of four experimental groups: nonpregnant controls, Suramin-treated nonpregnant rats, pregnant controls and pregnant Suramin-treated rats. Blood samples were collected before pregnancy and at gestational day 20 for analysis of renin and sFlt-1. The fetal and placental morphology were evaluated after caesarian section on gestational day 20.

RESULTS

The blood pressure of the pregnant Suramin-treated rats successively increased during pregnancy and differed by 17 mmHg at gestational day 20 compared with the pregnant control rats. In the pregnant Suramin-treated rats group, the renin levels increased (+122%) and the sFlt-1 levels decreased (-58%) during pregnancy. The pregnant Suramin-treated fetuses and placentae were smaller (2.8 g and 0.51 g) than the pregnant controls rats' fetuses and placentae (3.5 g and 0.56 g). Resorptions tended to be higher in the pregnant Suramin-treated rat litters compared with the pregnant control rat litters (P = 0.08). The area of the maternal blood vessels in the mesometrial triangle was smaller in the pregnant Suramin-treated rats group than in the pregnant control rats group.

CONCLUSION

The inhibition of uterine angiogenesis increases maternal blood pressure and compromises fetal and placental development. Placental hypoxia and subsequent activation of the renin-angiotensin system may play an important role for the hypertension.

Study of Association Between Hypertensive Disorders of Pregnancy and the Human Coagulation Factor XI Gene

OBJECTIVE

Hypertensive disorders of pregnancy (HDP) are among the most common and serious complications of pregnancy. Persuasive evidence implicaties genetic factors in the genesis of HDP. The aim of the present study was to assess the association between single-nucleotide polymorphisms (SNPs) in the human coagulation factor XI (F11) gene and HDP, by conducting a haplotype-based case-control study.

METHODS

We chose 3 SNPs (rs925453, rs925451, and rs12500151) in the human F11 gene as genetic markers. We then conducted an association study with 77 HDP patients and 154 age-matched non-HDP subjects.

RESULTS

The frequency of rs925453 genotypes significantly differed between the two groups. The frequency of the T-G-G haplotype was significantly higher in the HDP group than in the non-HDP group (p = 0.0002).

CONCLUSIONS

The T allele of rs925453 and the T-G-G haplotype appear to be useful genetic markers of HDP.

Comparison between essential hypertension and pregnancy-induced hypertension: a genetic perspective

Essential hypertension (EH) accounts for 80-90% of hypertension, and pregnancy-induced hypertension (PIH) is responsible for hypertension during pregnancy. Both considered multifactorial disorders. While both have many features in common, conditions and causes of these diseases have yet to be clarified. Since both diseases are associated with hypertension, the genetic backgrounds may contain common features. The present study reviewed similarities and differences between women with EH and PIH, with a particular focus on their genetic backgrounds.

The effect of sildenafil on the altered thoracic aorta smooth muscle responses in rat pre-eclampsia model

The pathophysiology of pre-eclampsia is still unknown thus effective primary prevention is not possible at the stage. The present study was conducted to research the smooth muscle responses in the pre-eclampsia model with suramin treated rats and the effect of phosphodiesterase-5 (PDE5) inhibitor on these responses. Rats of three groups; control, suramin and suramin+sildenafil were given intraperitoneal injections of saline, suramin or sildenafil citrate. Suramin injections caused increased blood pressure, protein in urine and caused fetal growth retardation. The use of sildenafil citrate straightened significantly both blood pressure and average fetus weight, but did not reach to control values. At the end of pregnancy, thoracic aorta rings were exposed to contractile and relaxant agents. KCl contraction responses, sodium nitroprusside and papaverine relaxation responses were similar in three groups. Contraction responses of phenylephrine, increased significantly in suramin group. Relaxation responses of acethylcholine and bradykinin decreased in suramin group. The use of sildenafil citrate partially straightened both relaxation and contraction responses, but did not reach to control values. In all groups in the presence of L-nitromonomethylarginine (L-NAME), 1H-(1, 2, 4) oxadiazole (4, 3-a) guinoxalin-1-one (ODQ) and indomethacin decreased the relaxation responses of acetylcholine and bradykinin. The cyclic guanosine monophosphate (cGMP) content of thoracic aorta tissue was determined by radioimmunoassay technique. The content of cGMP in suramin group decreased and use of sildenafil citrate increased the cGMP content but did not reach to control values. We conclude that in pre-eclampsia, the increase of contraction responses, the decrease of relaxation responses and the decrease of cGMP content can depend on insufficiency about synthesis or release of relaxant factors which was released from the vessel endothelium. The results in this study show that in pre-eclampsia; PDE5 inhibitors enhance endothelial function and may be used for protection. Further studies are needed to clear the efficiency and safety of PDE5 inhibitors.

Genes and the preeclampsia syndrome

Preeclampsia is specific to pregnancy and is still a leading cause of maternal and perinatal mortality and morbidity, affecting about 3% of women, but the underlying pathogenetic mechanisms still remain unclear. Immune maladaptation, placental ischemia and increased oxidative stress represent the main components discussed to be of etiologic importance, and they all may have genetic implications. Since the familial nature of preeclampsia is known for many years, extensive research on the genetic contribution to the pathogenesis of this severe pregnancy disorder has been performed. In this review, we will overview the linkage and candidate gene studies carried out so far as well as summarize important historical notes on the genetic hypotheses generated in preeclampsia research. Moreover, the influence of maternal and fetal genes and their interaction as well as the role of genomic imprinting in preeclampsia will be discussed.

Haplotype-based case-control study of estrogen receptor alpha (ESR1) gene and pregnancy-induced hypertension

Hypotheses about pregnancy-induced hypertension (PIH) have been proposed to explain the vascular damage that characterizes this disease. Reports indicate that estrogens and estrogen receptors play important physiological roles in cardiovascular diseases. There have been studies examining the association between coronary artery disease and the estrogen receptor alpha (ESR1) gene. The aim of the present work was to assess the association between PIH and single-nucleotide polymorphisms (SNPs) in the human ESR1 gene, by conducting a haplotype-based case-control study. Based on a database search at the web site of the National Center of Biotechnology Information, we chose five SNPs in the human ESR1 gene, and performed an association study using 95 PIH patients and 200 age-matched non-PIH subjects. The frequency of rs2881766 genotypes and alleles differed significantly between the two groups. There was no significant difference in overall distribution of genotypes or alleles of the other four SNPs. The T allele of rs2881766 was significantly more prevalent in the PIH group than in the non-PIH group. Haplotype-based case-control analysis revealed that there was a significant difference in overall distribution of the combinations rs2881766-rs1643821-rs988328 and rs2881766-rs1643821 between the PIH group and the non-PIH group (all or body mass index [BMI]-matched). One susceptibility haplotype for PIH and two resistance haplotypes for PIH were revealed by comparison between the PIH group and the non-PIH (BMI-matched) control group. In conclusion, the T allele of rs2881766 could be a useful genetic marker of PIH. The G-A-T haplotype of rs2881766-rs1643821-rs988328 and the G-A haplotype of rs2881766-rs1643821 appear to be resistance markers of PIH.

The 4G/5G polymorphism in the plasminogen activator inhibitor-1 gene is not associated with HELLP syndrome

Plasminogen activator inhibitor-1 (PAI-1) is a major inhibitor of fibrinolysis, and a single nucleotide insertion/deletion (4G/5G) polymorphism in the promoter region of the PAI-1 gene has been identified. Subjects homozygous for the 4G allele have the highest PAI-levels due to increased PAI-1 gene transcription. Pre-eclampsia, and one of its most severe forms, the HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome, are characterized by increased placental thrombosis based on a procoagulatory state in the mother. Several studies have investigated the role of the PAI-1 4G/5G polymorphism in pre-eclampsia, but no study has focused especially on HELLP syndrome. Therefore we aimed to assess the association between HELLP syndrome and the 4G/5G polymorphism in the PAI-1 gene. Genotyping of the PAI-1 4G/5G promoter polymorphism was performed in 102 Caucasian women with HELLP syndrome and 102 Caucasian women with uncomplicated pregnancies. The 4G/4G genotype was more frequent in women with HELLP syndrome than in controls (35.3% vs. 22.5%, respectively) but this difference was not significantly different (P = 0.129). The frequency of the 4G allele was 0.588 in patients and 0.515 in controls. These data suggest that women carrying a 4G/4G genotype of the PAI-1 gene are not at increased risk for developing HELLP syndrome and are thus in line with the majority of previous studies on the association between the PAI-1 4G/5G polymorphism and pre-eclampsia.

Fibrinolytic defects and recurrent miscarriage: a systematic review and meta-analysis

OBJECTIVE

To systematically review evidence of the association between fibrinolytic defects and recurrent miscarriage.

DATA SOURCES

MEDLINE, EMBASE, and references of retrieved articles (last update September 2006) were used.

METHODS OF STUDY SELECTION

Studies comparing the prevalence of fibrinolytic defects in patients with recurrent miscarriage and control women were reviewed. Of 111 potentially relevant studies, data from 14 were integrated with meta-analytic techniques and were presented as odds ratios (ORs).

TABULATION, INTEGRATION, AND RESULTS

Plasminogen activator inhibitor-1 4G/5G polymorphism (OR 1.65, 95% confidence interval [CI] 0.92-2.95) and increased plasminogen activator inhibitor activity were not significantly associated with recurrent miscarriage, although the latter showed profound heterogeneity across studies. Although factor XII C46T polymorphism is not associated with recurrent miscarriage (OR 1.07, 95% CI 0.52-2.22), factor XII deficiency is significantly associated (five studies, 1,096 women; OR 18.11, 95% CI 5.52-59.39), with minimal heterogeneity across studies. Factor XIII Val34Leu and Tyr204Phe polymorphisms were not associated with recurrent miscarriage (OR 1.24, 95% CI 0.46-3.34 and OR 2.61, 95% CI 0.45-15.16, respectively). There were no eligible studies found for the rest of the factors searched (urokinase-type plasminogen activator, tissue-type plasminogen activator, kallicrein, a2-antiplasmin, a2-macroglobulin, thrombin-activated thrombolysis inhibitor, and factor XI). Only a small minority of studies ascertained miscarriage according to specific criteria, and none of the studies provided equal examination for confounders in cases and controls.

CONCLUSION

Factor XII deficiency is associated with recurrent miscarriage. Data on the other factors either fail to show association or are quite limited.

Candidate-gene association study of mothers with pre-eclampsia, and their infants, analyzing 775 SNPs in 190 genes

Pre-eclampsia (PE) affects 5-7% of pregnancies in the US, and is a leading cause of maternal death and perinatal morbidity and mortality worldwide. To identify genes with a role in PE, we conducted a large-scale association study evaluating 775 SNPs in 190 candidate genes selected for a potential role in obstetrical complications. SNP discovery was performed by DNA sequencing, and genotyping was carried out in a high-throughput facility using the MassARRAY(TM) System. Women with PE (n = 394) and their offspring (n = 324) were compared with control women (n = 602) and their offspring (n = 631) from the same hospital-based population. Haplotypes were estimated for each gene using the EM algorithm, and empirical p values were obtained for a logistic regression-based score test, adjusted for significant covariates. An interaction model between maternal and offspring genotypes was also evaluated. The most significant findings for association with PE were COL1A1 (p = 0.0011) and IL1A (p = 0.0014) for the maternal genotype, and PLAUR (p = 0.0008) for the offspring genotype. Common candidate genes for PE, including MTHFR and NOS3, were not significantly associated with PE. For the interaction model, SNPs within IGF1 (p = 0.0035) and IL4R (p = 0.0036) gave the most significant results. This study is one of the most comprehensive genetic association studies of PE to date, including an evaluation of offspring genotypes that have rarely been considered in previous studies. Although we did not identify statistically significant evidence of association for any of the candidate loci evaluated here after adjusting for multiple testing using the false discovery rate, additional compelling evidence exists, including multiple SNPs with nominally significant p values in COL1A1 and the IL1A region, and previous reports of association for IL1A, to support continued interest in these genes as candidates for PE. Identification of the genetic regulators of PE may have broader implications, since women with PE are at increased risk of death from cardiovascular diseases later in life.

Relationship between polymorphisms in thrombophilic genes and preeclampsia in a Brazilian population

The purpose of this study was to evaluate the thrombophilic genes in pregnant women with and without preeclampsia independently or in combination. In a prospective case-control study, we investigated four polymorphisms in thrombophilic genes in 75 women with mild or severe preeclampsia and 145 women with normal pregnancy. The genotype frequencies were assessed and the odds ratio (OR) calculated. When we analyzed the polymorphisms independently and the development of preeclampsia, no association was observed [methylenetetrahydrofolate reductase (MTHFR) 677TT genotype, OR 2.07, 95% confidence interval (CI) 0.99-4.30; prothrombin mutation (F II) (GA or AA genotypes) OR 8.11, 95% CI 0.89-73.92; factor V Leiden (FV Leiden) OR 3.94, 95% CI 0.35-44.23; plasminogen activator inhibitor (PAI-1) 4G/4G genotype, OR 1.63, 95% CI 0.87-3.05] not even with severe preeclampsia subgroup analysis. However, when we investigated a possible interaction among these polymorphisms on the development of the preeclampsia, the OR for having one risk genotype, one or two genotype risk factors and two genotype risk factors compared to those without genotype risk factors were 1.97 (95% CI 1.08-3.59), 2.21 (95% CI 1.25-3.92) and 4.27 (95% CI 1.3-13.9), respectively. In conclusion, in the population analyzed, the presence of the genotype risk factors alone does not seem to be associated with the development of preeclampsia even in the severe presentation form. However, an interaction among the MTHFR, F II, FV and PAI-1 gene polymorphisms on the development of the preeclampsia was indicated.

Correlation between plasminogen activator inhibitor-1 4G/5G polymorphism and pre-eclampsia: an appraisal

AIM

Plasminogen activator inhibitor-1 (PAI-1) is an important inhibitor of the fibrinolytic system, so it is biologically plausible that elevated levels could suppress fibrinolysis and result in an increased risk of thrombosis. There is considerable controversy regarding the clinical role of PAI-1 4G/5G polymorphism as a risk factor of pre-eclampsia. Here, the author performs a summative analysis on the recent previous reports on the PAI-1 4G/5G and its correlation to pre-eclampsia.

METHOD

The metanalysis was performed in order to assess the correlation between the pattern of PAI-1 4G/5G polymorphism and pre-eclampsia. From the available six case-control studies, 880 patients and 810 controls are evaluated.

RESULTS

The overall frequencies of 4G allele for the patients and controls are 49.9 and 44.4, respectively. According to this study, 54.9% of subjects with 4G allele have pre-eclampsia while 43.1% of subjects without 4G allele have pre-eclampsia. From overall risk estimation, the subjects with 4G alleles have 1.27 times higher risk to pre-eclampsia.

CONCLUSION

According to this analysis, the author proposes that the pattern of PAI-1 4G/5G polymorphism might represent a useful marker of increased risk for pre-eclampsia. In addition, the lack of association between pattern of PAI-1 4G/5G and ethnicity of the patients can be demonstrated in this study.

Trombofilia congénita y aborto recurrente: estrategias diagnósticas y recomendaciones terapéuticas

Pregnancy is a well recognized thrombophilic risk factor. Recurrent abortion (RA) affect up to 3% of fertile couples. A 50% of these cases are considered as idiopathic. Some of them may have one or more than one thrombophilic alterations. RA may be related to placental flow abnormalities. Up to 1% to 5% of all pregnancies may be complicated with placental flow abnormalities. Antiphospholipid syndrome, PS, PC, ATIII deficiencies, factor V, prothrombin, methylentetrahydrofolate reductase, plasminogen activator inhibitor type 1, fibrinogen and factor XIII polymorphisms, have been strongly related to bad obstetric outcomes, specially RA. The presence of more than one thrombophilic factor may be present in pregnant women, rising the risk of suffering RA. All pregnant patients and those who planed a future conception having a history of thrombotic events, independently of their previous obstetric outcomes, need to be studied for thrombophilia. All patients with RA specially if it appeared in the late-pregnancy, have also to be studied. Early antiaggregant and/or anticoagulant therapy, reduces the maternal-fetal risk.

Placental dysfunction in Suramin-treated rats: impact of maternal diabetes and effects of antioxidative treatment

OBJECTIVE

The aim of the present study was to evaluate a rat model of placental dysfunction/preeclampsia in pregnancies complicated by maternal diabetes. A second objective was to evaluate the effects of vitamin E treatment in this model.

METHODS

Normal and streptozotocin-induced diabetic rats of two different strains (U and H) were given intraperitoneal (IP) injections of the angiogenesis inhibitor Suramin (Sigma Chemical Co, St Louis, MO) or saline in early pregnancy, and fed standard or vitamin E-enriched food. The outcome of pregnancy was evaluated on gestational day 20.

RESULTS

In both rat strains Suramin caused fetal growth retardation, decreased placental blood flow, and increased placental concentration of the isoprostane 8-iso-PGF(2alpha). In the U rats Suramin also caused increased fetal resorption rate, increased maternal blood pressure, decreased renal blood flow, and diminished maternal growth. Diabetes caused severe maternal and fetal growth retardation, increased resorption rate, and increased placental 8-iso-PGF(2alpha) concentration independent of Suramin administration. The maternal and fetal effects of Suramin and diabetes were more pronounced in the U strain than in the H strain. Vitamin E treatment improved the status of Suramin-injected diabetic rats: in U rats the blood pressure increase was normalized; and in both U and H rats the decreased placental blood flow was marginally enhanced, and the increase in placental 8-iso-PGF(2alpha) was partly normalized by vitamin E.

CONCLUSION

Suramin injections to pregnant rats cause a state of placental insufficiency, which in U rats resembles human preeclampsia. The induction of this condition is at least partly mediated by oxidative stress, and antagonized by antioxidative treatment. Maternal diabetes involves increased oxidative stress, and causes both maternal and fetal morbidity, which are only marginally affected by additional Suramin treatment.

Association study using single nucleotide polymorphisms in the estrogen receptor beta (ESR2) gene for preeclampsia

The pathophysiology of preeclampsia (PE) remains uncertain despite many research efforts. Actual hypotheses seek to explain the vascular damage that characterizes the disease. Recently, it was reported that the mouse disrupted estrogen receptor beta (ESR2) gene was associated with abnormal vascular function and hypertension. Moreover, some investigators have reported that subjects with a family history of hypertension have a statistically significant increased risk for PE. Thus, it is thought that the pathophysiology of PE overlaps that for hypertension. The aim of the present study was to investigate the relationships between single nucleotide polymorphisms (SNPs) in the human ESR2 gene and PE in Japanese subjects, and to assess the involvement of a family history of hypertension in these relationships. Based on a database search on the web site of the National Center of Biotechnology Information (NCBI), we chose four SNPs in the human ESR2 gene, and performed an association study in 84 PE patients and 160 age-matched non-PE subjects. The overall distribution in each SNP did not differ significantly between the two groups. However, after dividing the groups into subjects with and without a family history of hypertension, the allelic distribution of one of the SNPs (rs928554) revealed a positive association. Thus, a possible mutation linked to a SNP may prescribe a genetic predisposition for patients with a family history of hypertension in PE.

Placental dysfunction in Suramin-treated rats – a new model for pre-eclampsia

Impaired placentation and oxidative stress are proposed to play major roles in the pathogenesis of placental dysfunction and pre-eclampsia. This study was carried out to evaluate if inhibited angiogenesis by Suramin injections in early pregnancy may cause a condition resembling pre-eclampsia in rats. Rats of two different Sprague-Dawley strains, U and H, were given intraperitoneal injections of Suramin or saline in early pregnancy. The outcome of pregnancy was evaluated on gestational day 20. Suramin injections caused increased blood pressure and decreased renal blood flow in the U rats. In both rat strains Suramin decreased the placental blood flow and caused fetal growth retardation. In both strains the placental concentration of the isoprostane 8-epi-PGF2alpha was increased, indicating oxidative stress. The serum concentration of Endothelin-1 was increased in the U rats. The U strain had a lower basal placental blood flow, and the effects of Suramin were more pronounced in this strain. We conclude, that Suramin injections to pregnant rats cause a state of placental insufficiency, which partly resembles human pre-eclampsia. The induction of this condition is at least partly mediated by oxidative stress, and is subject to varied genetic susceptibility.

Thrombophilic Polymorphisms and Intrauterine Growth Restriction

BACKGROUND

The relationship between thrombophilic polymorphisms and intrauterine growth restriction remains unclear. Whereas a subset of these polymorphisms have received some attention, others have not.

METHODS

We conducted a case-control study of 493 cases of intrauterine growth restriction (birthweight less than the 10th percentile for gestational age and sex) and 472 controls (greater than the 10th percentile). We also conducted a family study including approximately 250 case trios (affected newborn, mother, and father) for each studied gene. Plasminogen activator inhibitor-1(PAI-1) 4G/5G and Factor XIII Val134Leu variants were compared between maternal and newborn cases and controls. Relative risks for newborn and maternal PAI-1 and Factor XIII genotypes in case trios were estimated using a log-linear model. Transmission of MTHFR C677T and 1298C haplotypes was analyzed in case trios, and the estimated haplotype distribution compared between cases and controls. Finally, we explored pairwise gene-gene interactions between all measured polymorphisms, including Factor V Leiden G1691A and Prothrombin G20210A.

RESULTS

PAI-1 and Factor XIII polymorphisms were not associated with an increased risk of intrauterine growth restriction in the case-control analysis, and the case-parent analysis showed no newborn or maternal excess genotype relative risk. No excess transmission of the MTHFR haplotypes was observed in case newborns, and the distribution of MTHFR haplotypes was similar between cases and controls. Some results were suggestive of interactions between genes.

CONCLUSIONS

Overall, there seems to be little or no indication that thrombophilic genes, at least individually, have an effect on intrauterine growth restriction.

Preeclampsia and its interaction with common variants in thrombophilia genes

Recently, it has been proposed that abnormalities in coagulation and fibrinolysis contribute to the development of preeclampsia by increasing the thrombotic tendency. This hypothesis was tested in women who have had preeclampsia (cases) compared with matched controls. Polymorphisms in the thrombophilia genes [plasminogen activator inhibitor type 1 [PAI-1 -675(4G/5G)], thrombin activatable fibrinolysis inhibitor (TAFI -438G/A and 1040C/T), methylenetetrahydrofolate reductase (MTHFR 677C/T), factor V (FV Leiden R/Q506), prothrombin (FII 20210G/A) and factor XIIIA (FXIIIA V/L34)] were determined in 157 women with preeclampsia and 157 women with uncomplicated pregnancy. The associated risk of preeclampsia was analyzed using logistic regression methods. The frequency distributions of the genotypes of these six polymorphisms in thrombophilia genes were similar in the case and control groups. We found no differences in the prevalence of genetic risk factors of thrombosis in women with preeclampsia compared with controls, which makes it unlikely that these polymorphisms are risk factors for preeclampsia.

Plasminogen Activator Inhibitor-1 4G Allele in the 4G/5G Promoter Polymorphism Increases the Occurrence of Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

In several acute life-threatening diseases, the 4G-allele in the 4G/5G-promotor polymorphism in the plasminogen activator inhibitor-1 (PAI-1) gene is associated with higher PAI-1 levels and increased poor outcome, probably by promoting the formation of microthrombi. The aim of the present study was to investigate whether the PAI-1 4G/5G polymorphism is associated with the occurrence of cerebral ischemia, rebleeding, and other events, and clinical outcome after aneurysmal subarachnoid hemorrhage.

METHODS

DNA was collected and analyzed in 126 patients with aneurysmal subarachnoid hemorrhage admitted to the Academic Medical Centre Amsterdam and University Medical Centre Utrecht in the Netherlands. All episodes of deterioration were classified according to predefined criteria. Causes of poor outcome and functional outcome were assessed 3 months after the initial bleeding according to the 5-point Glasgow Outcome Scale (GOS).

RESULTS

Secondary ischemia occurred more often in patients with the 4G genotype than in patients homozygous for the 5G allele (RR: 3.3; 95% CI: 1.1 to 10.0). No significant differences were found between the groups for rebleeding or other events. Patients with the 4G genotype tended to have a higher risk for poor outcome than patients with the 5G/5G genotype (RR 1.2; 95% CI 0.7 to 2.2).

CONCLUSIONS

The 4G allele in the PAI-1 gene increases the risk for cerebral ischemia after aneurysmal subarachnoid hemorrhage (SAH) and probably also the risk for poor outcome. After early aneurysm occlusion, treatment aimed at enhancing fibrinolysis might be effective to prevent and treat cerebral ischemia in patients with aneurysmal SAH.

Implication of an AGT Haplotype in a Multigene Association Study With Pregnancy Hypertension

Several association studies of candidate genes for preeclampsia and essential hypertension have led to discordant results, partly because of small sample sizes. Using a large population-based sample of pregnant women, we conducted an association study of 10 polymorphisms in 9 genes and aimed (1) to validate 10 published associations with preeclampsia or essential hypertension, (2) to investigate candidate polymorphisms previously associated with preeclampsia for association with essential hypertension and similarly with polymorphisms previously associated with essential hypertension. From a prospective sample of 3391 nulliparous French Canadian pregnant women, we identified 180 cases of preeclampsia, 203 cases of essential hypertension that were matched with normotensive control subjects (n=310 and 357, respectively). Polymorphisms were genotyped by allele-specific PCR. Among our candidate polymorphisms, the Met allele of Thr174Met of AGT was associated with preeclampsia ( P =0.0033). Haplotype analysis revealed that the A-Met-Thr (G1035A-Thr174Met-Met235Thr) haplotype was associated with a 2.1-fold increased risk of preeclampsia (95% CI, 1.4 to 3.4; P =0.0008). In conclusion, we observed a strong association between a specific AGT haplotype and preeclampsia in our population, without replicating previous published associations with either preeclampsia or essential hypertension. Our data support a role for AGT in genetic susceptibility to preeclampsia.

Association between plasminogen activator inhibitor 1 gene polymorphisms and preeclampsia

It is known that the plasminogen activator inhibitor 1 (PAI-1) protein levels are increased in placentas of preeclamptic subjects. Therefore, we assessed whether polymorphisms related to the transcriptional control of the PAI-1 gene (-675 4G/5G and -844G/A) are associated with mild preeclampsia. We compared 52 women with preeclampsia to 80 women with a normal pregnancy. None of the preeclamptic women suffered from the severe form of preeclampsia. DNA was extracted from blood, and -675 4G/5G and -844G/A genotypes of the PAI-1 gene were determined. Since it has been shown that the presence of factor V Leiden, prothrombin G20210A, and MTHFR C677T gene variants may be associated with preeclampsia, their frequency was also evaluated in our study groups. The factor V Leiden, PT G20210A, and MTHFR C677T gene variants were not associated with preeclampsia. In the case of the -675 4G/5G polymorphism, genotypes 4G/4G and 5G/5G were more prevalent in the preeclamptic and in the control group, respectively. In the case of -844 G/A polymorphism, genotypes A/A and G/G were more prevalent in the preeclamptic and in the control group, respectively. By using the chi(2) test for trend, differences for both genotypes were significant (p = 0.0141 for the -675 genotypes and p = 0.0492 for the -844 genotypes). The frequency of the 4G and 5G alleles of the -675 gene polymorphism was significantly different between preeclamptic and normal women (p = 0.032). Differently, the allelic frequency of the -844 gene polymorphism did not show significant differences between preeclamptic and normal women (p = 0.083). In conclusion, the hypofibrinolytic genotypes 4G/4G and A/A at positions -675 and -844 of the PAI-1 gene are associated with the occurrence of mild preeclampsia independently of thrombophilic mutations of the factor V, prothrombin, and MTHFR genes.

The search for thrombophilic gene mutations in women with gestational hypertension does not help in predicting poor pregnancy outcome

OBJECTIVE

To evaluate whether genetic thrombophilic mutations, biochemical and biophysical indices help to predict pregnancy outcome in women with gestational hypertension.

DESIGN AND METHODS

A group of 59 women with gestational hypertension were prospectively tested between 24 and 26 weeks of gestation for: (i) DNA analysis to search for gene mutations of Factor V Leiden, prothrombin, methylenetetrahydrofolate reductase and plasminogen activator inhibitor type 1 (PAI-I) polymorphism; (ii) maternal serum concentrations of homocysteine and PAI-1, activated protein resistance and Factor II:C activity levels; (iii) mean uterine arterial resistance index (RI) by Doppler velocimetry; and (iv) history of hypertensive disorders in relatives (the mother and/or the father). Pregnancy outcome was evaluated, and considered 'poor' when patients developed severe pre-eclampsia, haemolysis-elevated liver enzymes-low platelets (HELLP) syndrome, fetal growth restriction (FGR), thromboembolic complications and disseminated intravascular coagulopathy (DIC).

RESULTS

Eighteen women had a poor pregnancy outcome (11 with severe pre-eclampsia, of whom two had superimposed FGR; three with full HELLP syndrome, of whom one had DIC; four with FGR) and delivered, by emergency Caesarean section, neonates with a significantly lower mean gestational age (P < 0.0001) and birthweight (P < 0.0001). History of hypertensive disorders was significantly (P < 0.001) more common in the women group with poor (11 of 18) than normal (10 of 41) outcome. In addition, patients with a poor pregnancy outcome did not have a higher incidence of gene polymorphisms incidence, but significantly (P < 0.01) higher Factor II:C activity levels and significantly (P < 0.0001) higher mean uterine arterial RI than women with normal pregnancy outcome.

CONCLUSIONS

Only Factor II:C activity levels, uterine arterial Doppler and a history of familial hypertension are useful in predicting poor pregnancy outcome in gestational hypertension.

Plasminogen Activator Inhibitor-1 Polymorphism in Women with Pre-eclampsia

We determined whether or not genetic variability in the promoter region of the gene encoding plasminogen activator inhibitor-1 (PAI1) contributes to individual differences in susceptibility to the development of preeclampsia. The study involved 133 preeclamptic and 115 healthy control pregnant women who were genotyped for a single-nucleotide insertion/deletion polymorphism (4G/5G) at position -675 in the PAI1 gene promoter. Furthermore, the frequencies of the alleles in the general middle-aged population are presented for comparison. Chi-square analysis was used to assess genotype and allele frequency differences between preeclamptic women and controls. A similar allelic distribution of PAI1 4G/5G polymorphism was observed in the two groups, with the frequency of the variant 4G allele being 50.4% in the preeclampsia group and 54.3% in the control group (p = 0.377; OR = 0.85, 95% CI = 0.60-1.22). Accordingly, the genotype distribution of the PAI1 4G/5G polymorphism in the preeclamptic and control groups was found to be similar (p = 0.68). Overall, this genotype data on fertile women is almost identical to that in the general middle-aged Finnish population. The 4G/5G polymorphism of the PAI1 gene promoter is unlikely to be a major genetic predisposing factor as regards preeclampsia in subjects from eastern Finland. These results are not suggestive of an important contribution of the PAI1 genotype on preeclampsia across populations.

Genetics of preeclampsia: what are the challenges?

Despite recent efforts to identify susceptibility genes of preeclampsia, the genetic determinants of the condition remain ill-defined, as is the situation for most disorders of complex inheritance patterns. The angiotensinogen, factor V, and methylenetetrahydrofolate reductase genes have been investigated in different populations, as have other genes involved in blood pressure, vascular volume control, thrombophilia, lipid metabolism, oxidative stress, and endothelial dysfunction. The study of the genetics of complex traits is faced with both methodological and genetic issues; these include adequate sample size to allow for the identification of modest genetic effects, of gene-gene and gene-environment interactions, the study of adequate quantitative traits and extreme phenotypes, haplotype analyses, statistical genetics, genome-wide (hypothesis-free) versus candidate-gene (hypothesis-driven) approaches, and the validation of positive associations. The use of genetically well-characterized populations showing a founder effect, such as the French-Canadian population of Quebec, in genetic association studies, may help to unravel the susceptibility genes of disorders showing complex inheritance, such as preeclampsia. It is necessary to better evaluate the role of the fetal genome in the resulting predisposition to preeclampsia and its complications. Eventually, we may be able to integrate genetic information to better identify the women at risk of developing preeclampsia, and to improve the management of those suffering from this condition.

Inherited Thrombophilia: Impact on Human Reproduction

The development of thrombotic disorders is a major threat for young women during pregnancy. It is one of the main causes of pregnancy-related disorders, which may also result in harm for the conceptus. Successful pregnancies require an even balance of coagulation and fibrinolysis, in order to secure stabilization of the basal plate as well as adequate placental perfusion. Thrombophilia is a laboratory definition for pre-disposing factors of thrombosis, which can be inherited or acquired. Many individuals, who carry a thrombotic defect remain asymptomatic, at least until additional boosting factors arise. The documentation of thrombophilic causes of recurrent miscarriage or pregnancy-related disorders is important, because of availability of effective early treatment. There is a rapidly growing awareness on the relationship of genetic factors influencing hemostasis and pregnancy-related disorders. The aim of our review is to summarize this knowledge, focusing on common genetic variations.

Inherited thrombophilia and poor pregnancy outcome

Gestational vascular complications are a major cause of maternal and fetal morbidity.A growing body of evidence suggests a significant role for inherited thrombophilia in the development of gestational vascular complications. While the majority of women with thrombophilia will have an uneventful gestation, case-control studies demonstrated that thrombophilia is more prevalent in cohorts of women with pregnancy loss and early-onset pre-eclampsia. Placental abruption and severe intrauterine growth restriction (IUGR) may also be associated with thrombophilia. Placental pathological findings in women with thrombophilia are hallmarked by thrombosis and fibrin deposition potentially to a greater degree than in normal pregnancy. Preliminary non-randomized studies suggest a benefit for prophylaxis with unfractionated and low-molecular-weight heparin (LMWH), and prospective randomized trials are in progress to define whether LMWH is effective in preventing pregnancy loss and other gestational vascular complications in women with thrombophilia and previous fetal wastage.

Plasminogen activator inhibitor type 1 (PAI1) and platelet glycoprotein IIIa (PGIIIa) polymorphisms in Black South Africans with pre-eclampsia

BACKGROUND

Association of fibrin abnormalities with pre-eclampsia prompted this study to examine whether polymorphisms in the plasminogen activator inhibitor Type 1 and platelet glycoprotein IIIa genes constitute risk factors for this condition.

METHODS

A group of 151 Black Zulu-speaking pre-eclamptics was examined for 4G/5G plasminogen activator inhibitor Type 1 and PlA1/A2 platelet glycoprotein IIIa polymorphic alleles using standard techniques. Results were compared with those found in 217 ethnically matched healthy normotensive pregnant women who had normal full-term gestations.

RESULTS

Pre-eclamptic patients had a slightly higher frequency of the 4G plasminogen activator inhibitor Type 1 allele (15%) compared with the controls (12%); this was reflected also in the heterozygote frequency (28% and 22%) for the patients and the controls, respectively. These differences were not significant. Only 2% of this population was found to be homozygous for the 4G allele. No differences were observed in the platelet glycoprotein IIIa polymorphism genotype and allele frequency distribution between the patients and the controls.

CONCLUSIONS

Neither the 4G allele of the plasminogen activator inhibitor Type 1 nor the PlA2 allele of the platelet glycoprotein IIIa have any significant role as risk factors in the patho-etiology of pre-eclampsia in Black South Africans, although these genes cannot yet be excluded as contributory to this disorder. It is possible that the underlying causes of pre-eclampsia may vary between different ethnic populations.

Searching for preeclampsia genes: the current position

Although there is substantial evidence that preeclampsia has a genetic background, the complexity of the processes involved and the fact that preeclampsia is a maternal-fetal phenomenon does not make the search for the molecular basis of preeclampsia genes easy. It is possible that the single phenotype 'preeclampsia' in fact should be divided into different sub-groups on genetic or biochemical level. In the present review, the preeclampsia phenotype and its pathophysiologic features are discussed. Family studies and postulated inheritance models are summarized. A systematic overview is given on the numerous candidate gene studies and gene-expression studies performed so far and on the currently available genome-wide scan data. Despite extensive research the molecular genetic basis of preeclampsia remains unclear. Future studies will hopefully enhance our insights in the molecular pathogenesis of preeclampsia.

PAI-1 gene 4G/5G genotype: A risk factor for thrombosis in vessels of internal organs

Although the common 4G/5G polymorphism in the promoter of the PAI-1 gene was suggested to be a risk factor for some of the thrombotic disorders, its significance in the development of thrombosis is still controversial. This study presents the data on a total of 357 patients with different types of thrombosis and 281 unrelated healthy controls. It was found that the 4G/4G genotype is associated with a higher risk of thrombosis (OR, 1.7; 95% CI, 1.1-2.5). Patients were divided into five distinct groups according to the site of thrombosis. Both 4G/4G and 4G/5G genotypes were associated with a higher risk of thrombosis development in a group of 69 patients with internal organ thrombosis (OR, 6.35; 95% CI, 2.5-16.1 and OR, 4.85; 95% CI, 2.0-12.1, respectively). Interestingly, this association was even stronger in a subgroup of 33 patients with portal vein thrombosis (PVT) and 4G/4G and 4G/5G genotypes conferred more than 10- and 6-fold increases in the risk of developing PVT (95% CI: 2.3-47.1 and 1.4-28.8), respectively. No statistically significant association was found between 4G/4G genotype and the groups of deep vein thrombosis (126 patients), cerebral thrombosis (80 patients), retinal thrombosis (72 patients), and purpura fulminans (16 patients). Factor V Leiden or prothrombin G20210A mutations did not emerge as additional risk factors for thrombosis in any of the groups studied. To conclude, this study suggests that there may be an association between 4G/4G and 4G/5G genotypes and the thrombosis in vessels of internal organs especially in the portal veins.

Detection and quantification of insertion/deletion variations by allele-specific real-time PCR: application for genotyping and chimerism analysis

The DNA-based quantitative analysis of genetic chimerism is becoming increasingly more important for molecular biology in general and molecular medicine in particular. Useful genomic targets for these analyses are polymorphic sequences, but here the problem of a reliable quantification with high dynamic range is not yet satisfactorily solved. To this end we have combined the allele-specific amplification with a real-time PCR-based quantification for rapid allelotyping and chimerism analysis. The sequence variations are discriminated by the 3'-end of the allele-specific primer. Amplification is monitored by SYBR-Green I fluorescence. We demonstrate the efficiency of this method for two clinically relevant targets: (i) the 10 bp insertion/deletion polymorphism in the promoter of the factor VIIc (F-VIIc) gene and (ii) the 4G/5G single nucleotide polymorphism in the promoter of the plasminogen activator inhibitor-1 (PAI-1) gene. Both polymorphisms are associated with clinical risk factors. Allelotyping results were in complete agreement with those obtained by reference methods. Mixed chimeric DNA samples could be quantified reliably with a dynamic range of 1:3000 for an easy target (F-VIIc) and of 1:64 for a difficult target (PAI-1). Our protocol is particularly useful for rapid, reliable and inexpensive genotyping and quantitative chimerism analysis without requiring expensive fluorophor dye labelled probes.

Plasminogen activator inhibitor-1 and the kidney

Plasminogen activator inhibitor-1 (PAI-1) is a serine protease inhibitor that was isolated 20 years ago. First recognized as an inhibitor of intravascular fibrinolysis, it is now evident that PAI-1 is a multifunctional protein with actions that may be dependent on or independent of its protease inhibitory effects. The latter often involve interactions between PAI-1 and vitronectin or the urokinase receptor. The protease-inhibitory actions of PAI-1 extend beyond fibrinolysis and include extracellular matrix turnover and activation of several proenzymes and latent growth factors. PAI-1 has been implicated in several renal pathogenetic processes, including thrombotic microangiopathies and proliferative and/or crescentic glomerulopathies. Most recently, it has become clear that PAI-1 also plays a pivotal role in progressive renal disease, both glomerulosclerosis and tubulointerstitial fibrosis. An active area of present research interest, untold stories are likely to be uncovered soon.