Genetic variation in fibrinogen; its relationship to fibrinogen levels and the risk of myocardial infarction and ischemic stroke

The inverted U-shaped association between blood fibrinogen and rehospitalization risk in patients with heart failure

Fibrinogen, a biomarker of thrombosis and inflammation, is related to a high risk for cardiovascular diseases. However, studies on the prognostic value of blood fibrinogen concentrations for heart failure (HF) patients are few and controversial. We performed a retrospective analysis among acute or deteriorating chronic HF patients admitted to a hospital in Sichuan, China, between 2016 and 2019, integrating electronic health care records and external outcome data (N = 1532). During 6 months of follow-up, 579 HF patients were readmitted within 6 months, and 46 of them died. Surprisingly, we found an inverted U-shaped association of blood fibrinogen levels with risk of readmission within 6 months but not with risk of death within 6 months. It was found that HF patients had the highest risk for readmission within 6 months after reaching the turning point for blood fibrinogen (2.4 g/L). In HF patients with low fibrinogen levels < 2.4 g/L, elevated fibrinogen concentrations were still significantly associated with a higher risk for readmission within 6 months [OR = 2.3, 95% CI (1.2, 4.6); P = 0.014] after controlling for relevant covariates. There was no significant association between blood fibrinogen and readmission within 6 months [(OR = 1.0, 95% CI (0.9, 1.1); P = 0.675] in HF patients with high fibrinogen (> 2.4 g/L). The effect difference for the two subgroups was significant (P = 0.014). However, we did not observe any association between blood fibrinogen and death within 6 months stratified by the turning point, and the effect difference for the stratification was not significant (P = 0.380). We observed an inverted U-shaped association between blood fibrinogen and rehospitalization risk in HF patients for the first time. Additionally, our results did not support that elevated blood fibrinogen was related to increased death risk after discharge.

Which one predicts mortality better in acute ischemic stroke: negative vs positive acute-phase reactants

AIM

The aim of the study is to investigate the relationship between negative acute-phase reactants and positive acute-phase reactants with in-hospital mortality in patients diagnosed with acute ischemic stroke (AIS) in the emergency department (ED).

METHODS AND MATERIALS

Patients aged 18 and older who presented to the ED of a tertiary hospital with AIS were included in the study. Demographic and clinical characteristics, laboratory parameters, acute-phase reactants, National Institutes of Health Stroke Scale (NIHSS), and outcome data of the included patients were recorded on a standard data form.

RESULTS

A total of 588 patients were included in the study. When the in-hospital mortality of patients was examined, the mortality rate was 17.7%. In the analysis for predicting mortality, it was determined that albumin had the highest predictive power between the area under the curve (AUC) and the determined predictive values (AUC: 0.759, 95% CI 0.707-0.810, p < 0.001). The analyses of the study data revealed that albumin (<0.001) and TF (p = 0.049), which are negative acute-phase reactants, were independent predictors of mortality. According to our study data, in patients with AIS, for each unit decrease in albumin level at the time of ED admission, the risk of mortality increased by 0.868 times, and for each unit decrease in TF level, the risk of mortality increased by 0.593 times.

CONCLUSION

According to the study data, albumin and TF levels, which are negative acute-phase reactants, are independent determinants of in-hospital mortality in patients with acute ischemic stroke in the emergency department.

Factor VII R353Q (rs6046), FGA A6534G (rs6050), and FGG C10034T (rs2066865) Gene Polymorphisms and Risk of Recurrent Pregnancy Loss in Iranian Women

Recurrent pregnancy loss is a multi factorial and heterogeneous disorder defined as two or more consecutive pregnancy losses before 20 weeks' gestation. Gene polymorphisms including factor VII R353Q (rs6046), fibrinogen alpha chain A6534G (rs6050) and fibrinogen gamma chain C10034T (rs2066865) have potential role in thrombophilia and the relation between these three polymorphisms and an increased risk of venous thrombosis have been reported. As thrombophilia is associated with a considerable proportion of pregnancy loss and the association between these gene polymorphisms and recurrent pregnancy loss remains controversial, the aim of the present study was to evaluate the relation of these polymorphisms and recurrent pregnancy loss in Iranian women. A total of 144 women with a history of two or more consecutive miscarriages as the patient group and 150 healthy women with two live births and no history of pregnancy loss as the control group were included in the study. Polymerase chain reaction and restriction fragment length polymorphism were used for genotyping. The results were validated by DNA sequencing. The SPSS, SNPStats and Finch TV were used to analyze the results. Factor VII R353Q (rs6046) gene polymorphism showed a significant difference between RPL patients and the control group according to multiple logistic regression models [codominant (OR=0.38; 95% CI=0.23-0.63, P≤0.0001), dominant (OR=0.32; 95% CI=0.20-0.52, P≤0.0001), over dominant (OR=0.46; 95% CI=0.29-0.75, P=0.0017) and log-additive (OR=0.35; 95% CI=0.23-0.53, P≤0.0001)]. Fibrinogen alpha chain A6534G (rs6050) and fibrinogen gamma chain C10034T (rs2066865) gene polymorphisms showed no correlation with recurrent pregnancy loss. Factor VII R353Q (rs6046) gene polymorphism can be considered a risk factor for recurrent pregnancy loss. Further studies in larger populations are needed to confirm the findings.

Fibrinogen and fibrin: synthesis, structure, and function in health and disease

Fibrinogen is an extraordinary molecule by any estimation. It is large, structurally intricate, and circulates at high concentrations. Its biological end product, insoluble fibrin(ogen) or fibrin, can assume a diverse array of conformations with the ability to interact with numerous plasma proteins and cells and withstand biochemical and biomechanical disruption to facilitate wound healing. Quantitative and qualitative defects in fibrinogen or fibrin are associated with bleeding, thrombosis, inflammation, and diseases affected by these processes. Numerous studies investigating mechanisms by which fibrin(ogen) and fibrin contribute to health and disease have been published. This review for the 20th-anniversary series in the Journal of Thrombosis and Haemostasis summarizes interesting aspects of fibrin(ogen) biology, biochemistry, biophysics, and physiology and highlights exciting findings published in the past 2 decades.

From multi-omics approaches to personalized medicine in myocardial infarction

Myocardial infarction (MI) is a prevalent cardiovascular disease characterized by myocardial necrosis resulting from coronary artery ischemia and hypoxia, which can lead to severe complications such as arrhythmia, cardiac rupture, heart failure, and sudden death. Despite being a research hotspot, the etiological mechanism of MI remains unclear. The emergence and widespread use of omics technologies, including genomics, transcriptomics, proteomics, metabolomics, and other omics, have provided new opportunities for exploring the molecular mechanism of MI and identifying a large number of disease biomarkers. However, a single-omics approach has limitations in understanding the complex biological pathways of diseases. The multi-omics approach can reveal the interaction network among molecules at various levels and overcome the limitations of the single-omics approaches. This review focuses on the omics studies of MI, including genomics, epigenomics, transcriptomics, proteomics, metabolomics, and other omics. The exploration extended into the domain of multi-omics integrative analysis, accompanied by a compilation of diverse online resources, databases, and tools conducive to these investigations. Additionally, we discussed the role and prospects of multi-omics approaches in personalized medicine, highlighting the potential for improving diagnosis, treatment, and prognosis of MI.

Fibrinogen and Atherosclerotic Cardiovascular Diseases-Review of the Literature and Clinical Studies

Atherosclerotic cardiovascular diseases (ASCVD), including coronary artery disease, cerebrovascular disease, and peripheral arterial disease, represent a significant cause of premature death worldwide. Biomarkers, the evaluation of which would allow the detection of ASCVD at the earliest stage of development, are intensively sought. Moreover, from a clinical point of view, a valuable biomarker should also enable the assessment of the patient’s prognosis. It has been known for many years that the concentration of fibrinogen in plasma increases, inter alia, in patients with ASCVD. On the one hand, an increased plasma fibrinogen concentration may be the cause of the development of atherosclerotic lesions (increased risk of atherothrombosis); on the other hand, it may be a biomarker of ASCVD, as it is an acute phase protein. In addition, a number of genetic polymorphisms and post-translational modifications of fibrinogen were demonstrated that may contribute to the risk of ASCVD. This review summarizes the current data on the importance of fibrinogen as a biomarker of ASCVD, and also presents the relationship between molecular modifications of this protein in the context of ASCVD.

Extension of the Human Fibrinogen Database with Detailed Clinical Information—The αC-Connector Segment

Fibrinogen, an abundant plasma glycoprotein, is involved in the final stage of blood coagulation. Decreased fibrinogen levels, which may be caused by mutations, are manifested mainly in bleeding and thrombotic disorders. Clinically relevant mutations of fibrinogen are listed in the Human Fibrinogen Database. For the αC-connector (amino acids Aα240–410, nascent chain numbering), we have extended this database, with detailed descriptions of the clinical manifestations among members of reported families. This includes the specification of bleeding and thrombotic events and results of coagulation assays. Where available, the impact of a mutation on clotting and fibrinolysis is reported. The collected data show that the Human Fibrinogen Database reports considerably fewer missense and synonymous mutations than the general COSMIC and dbSNP databases. Homozygous nonsense or frameshift mutations in the αC-connector are responsible for most clinically relevant symptoms, while heterozygous mutations are often asymptomatic. Symptomatic subjects suffer from bleeding and, less frequently, from thrombotic events. Miscarriages within the first trimester and prolonged wound healing were reported in a few subjects. All mutations inducing thrombotic phenotypes are located at the identical positions within the consensus sequence of the tandem repeats.

An association between fibrinogen gene polymorphisms and diabetic peripheral neuropathy in young patients with type 1 diabetes

In complex etiopathogenesis of diabetic peripheral neuropathy (DPN), hemostatic dysfunction and subclinical inflammation play a possible role. Fibrinogen is involved in both the hemostatic and inflammatory pathways, so we hypothesize that fibrinogen gene polymorphisms might be associated with DPN. A total of 127 young patients with type 1 diabetes (T1D) (average age, 18.5 ± 4.65 years; average diabetes duration, 14.5 ± 2.26 years) and 90 healthy controls were enrolled into the study. Basic biochemical and coagulation parameters were measured and gene polymorphisms of fibrinogen alpha (rs6050) and beta (rs1800790) were established. DPN was diagnosed in 38 diabetic patients by neurological examination. AA genotype and A allele of rs1800790 polymorphism of fibrinogen beta were associated with increased risk of DPN (odds ratio [OR] 4.537, 95% confidence interval [95CI] 1.14-19.94, p = 0.019 and OR 1.958, 95CI 1.038-3.675, p = 0.029, respectively). No association was found between DPN and rs6050 gene polymorphisms. Plasma fibrinogen concentration significantly correlated with HbA1c (Spearman's correlation coefficient [r] = 0.54) and HDL cholesterol (r = - 0.67). A allele and AA genotype of rs1800790 seem to be associated with DPN in young patients with T1D. Further studies are appropriate to elucidate the role of fibrinogen gene polymorphisms in the complex etiology of DPN.

Association of fibrinogen and plasmin inhibitor, but not coagulation factor XIII gene polymorphisms with coronary artery disease

BACKGROUND

In the final phase of clot formation, fibrinogen constitutes frame, whereas factor XIII (FXIII) active form is responsible for the covalent cross-linking of fibrin fibres and plasmin inhibitor (PI), thus contributing to clot stability. It could be expected that any change of coagulation factors' structure affects the clot formation and modulates the atherothrombotic risk. The aim was to determine the frequency of four single nucleotide polymorphisms: (i) A > G in codon 312 of the fibrinogen α-chain gene (rs6050, Thr312AlaFGA), (ii) C > T at position 10034 of the 3 - untranslated region in the fibrinogen γ-chain gene (rs2066865, 10034C > T FGG), (iii) C > T in codon 564 of the FXIII-A subunit gene (rs5982, Pro564LeuFXIII-A), and (iv) C > T in codon 6 of the plasmin inhibitor gene (rs2070863, Arg6TrpPI) in Croatian patients and their association with coronary artery disease (CAD).

METHODS

We performed the unrelated case-control association study on the consecutive sample of patients 18 years old, who had undergone coronary angiography for investigation of chest pain and suspected CAD. The cases were patients with confirmed CAD (N=201), and the controls were the subjects with no CAD (N=119). Samples were genotyped using PCR-RFLP analysis.

RESULTS

Observed frequencies of the rare alleles of Thr312Ala FGA, 10034C > T FGG, Leu564Pro FXIII-A and Arg6Trp PI polymorphisms were 21%, 17%, 14%, 20%, respectively. Patients with 10034C > T FGG CC genotype had 3.5 times (95% CI 1.02-12.03) higher adjusted odds for CAD than patients with 10034C > T FGG TT genotype. Patients with Arg6Trp PI CC genotype had 3.86 times (95% CI 1.23-12.12) higher odds for CAD than patients with Arg6Trp PI TT genotype. It seems that those genotype-related higher odds are also male-gender related. No difference was observed regarding any other investigated polymorphism.

CONCLUSIONS

Our finding suggests that 10034C > T FGG and Arg6Trp PI are associated with CAD.

A Mendelian randomization of γ' and total fibrinogen levels in relation to venous thromboembolism and ischemic stroke

Fibrinogen is a key component of the coagulation cascade, and variation in its circulating levels may contribute to thrombotic diseases, such as venous thromboembolism (VTE) and ischemic stroke. Gamma prime (γ') fibrinogen is an isoform of fibrinogen that has anticoagulant properties. We applied 2-sample Mendelian randomization (MR) to estimate the causal effect of total circulating fibrinogen and its isoform, γ' fibrinogen, on risk of VTE and ischemic stroke subtypes using summary statistics from genome-wide association studies. Genetic instruments for γ' fibrinogen and total fibrinogen were selected, and the inverse-variance weighted MR approach was used to estimate causal effects in the main analysis, complemented by sensitivity analyses that are more robust to the inclusion of pleiotropic variants, including MR-Egger, weighted median MR, and weighted mode MR. The main inverse-variance weighted MR estimates based on a combination of 16 genetic instruments for γ' fibrinogen and 75 genetic instruments for total fibrinogen indicated a protective effect of higher γ' fibrinogen and higher total fibrinogen on VTE risk. There was also a protective effect of higher γ' fibrinogen levels on cardioembolic and large artery stroke risk. Effect estimates were consistent across sensitivity analyses. Our results provide evidence to support effects of genetically determined γ' fibrinogen on VTE and ischemic stroke risk. Further research is needed to explore mechanisms underlying these effects and their clinical applications.

Evaluation of single nucleotide polymorphisms in 6 candidate genes and carotid intima-media thickness in community-dwelling residents

Evidence suggests the existence of association between a large panel of modifiable biomarkers representing inflammation, coagulation, paraoxonase, and endothelial activation pathways and carotid atherosclerosis. Thus, this study investigated whether CRP, FGA, FGB, FGG, PON1, and EDNRA gene variants affected plasma hs-CRP, fibrinogen levels, and thickness of carotid intima media thickness (IMT). Nineteen single-nucleotide polymorphisms of CRP, FGA, FGB, FGG, PON1, and EDNRA genes were examined in 480 participants from 160 families. Carotid IMT was measured by ultrasound. Generalized linear models with generalized estimating equation were utilized to consider the dependence of subjects within families. In the recessive model, homozygotes for the minor alleles of rs1800789, rs1800790 and rs4220 SNPs in FGB gene indicated a reduced risk of IMT (Exp. β = 0.89, 0.89, 0.88), which remained significant after adjustment for confounding factors. Significant interaction effects between CRP SNP rs1130864 and rs3093059 and gender for IMT were observed with a significant association in men only. Men carrying minor-minor genotype of CRP SNP rs1130864 and rs3093059 had 0.70- and 0.78-fold lower IMT than men carrying minor-major/major-major genotype. We also observed that the interaction of CRP SNP rs1130864 and rs3093059 with obesity on IMT, hs-CRP and fibrinogen levels. These results support the hypothesis that inflammatory genes are involved in atherosclerosis, most likely via complex gene-gender and gene-obesity interactions.

Association of β-fibrinogen polymorphisms and venous thromboembolism risk: A PRISMA-compliant meta-analysis

BACKGROUND

Venous thromboembolism (VTE) is a multifactorial disease in which genetic and acquired risk factors may contribute to disease pathogenesis. Several studies have demonstrated that β-fibrinogen (FGB) polymorphisms are associated with the risk of VTE. However, the results of these studies were not totally consistent. In this paper, we performed a meta-analysis to further investigate the relationship between FGB polymorphisms and susceptibility to VTE.

METHODS

To identify studies pertinent to the focused question, the following databases were systematically searched: PubMed, EMBASE, Web of Science, China National Knowledge Infrastructure, and Wanfang Data. The strength of correlations was evaluated by calculating pooled odds ratios (ORs) and 95% confidence intervals (95% CIs). Subgroup analyses stratified by ethnicity, type of disorders, and source of control were also performed.

RESULTS

Overall, A total of 18 relevant case-control studies met the inclusion criteria and were incorporated in this meta-analysis, involving 3033 VTE cases and 4547 healthy controls. FGB -455G>A polymorphism and -148C>T polymorphism were not significantly associated with susceptibility to VTE in overall populations. However, results of stratified analysis demonstrated that among Caucasian population, the -455G>A mutation was negatively associated with the risk of VTE under all genetic comparison models (A:G OR = 0.80 95% CI = 0.70-0.91; GA + AA:GG OR = 0.80 95% CI = 0.68-0.93; GA:GG OR = 0.84 95% CI = 0.71-0.98; AA:GG + GA OR = 0.61 95% CI = 0.43-0.87; AA:GG OR = 0.57 95% CI = 0.40-0.82), which indicates FGB -455G>A polymorphism may be a protective factor for VTE. There was no correlation between -148C>T polymorphism and susceptibility to VTE in all subgroup analyses.

CONCLUSION

FGB -455G>A polymorphism was associated with a decreased risk of VTE among the Caucasian population.

Meta-Analysis of Factor V, Factor VII, Factor XII, and Factor XIII-A Gene Polymorphisms and Ischemic Stroke

Numerous studies examined the association between factors FV, FVII, FXII, and FXIII-A gene polymorphisms and ischemic stroke, but conclusive evidence is yet to be obtained. Thus, this meta-analysis aimed to investigate the novel association of FV rs1800595, FVII rs5742910, FXII rs1801020, and FXIII-A rs5982 and rs3024477 polymorphisms with ischemic stroke risk. A systematic review was performed on articles retrieved before June 2018. Relevant data were extracted from eligible studies and meta-analyzed using RevMan version 5.3. The strength of association between studied polymorphisms and ischemic stroke risk was calculated as odds ratios and 95% confidence intervals, by applying both fixed- and random-effect models. A total of 25 studies involving 6100 ischemic stroke patients and 9249 healthy controls were incorporated in the final meta-analysis model. Specifically, rs1800595, rs5742910, rs1801020, rs5982, and rs3024477 consisted of 673, 3668, 922, 433, and 404 cases, as well as 995, 4331, 1285, 1321, and 1317 controls, respectively. The pooled analysis indicated that there was no significant association of FV rs1800595, FVII rs5742910, FXII rs1801020, FXIII-A rs5982, and FXIII-A rs3024477 polymorphisms with ischemic stroke risk, under any genetic models (dominant, recessive, over-dominant, and allelic). The present meta-analysis concluded that FV rs1800595, FVII rs5742910, FXII rs1801020, and FXIII-A rs5982 and rs3024477 polymorphisms are not associated with ischemic stroke risk.

Thrombophilia screening in young patients with cryptogenic stroke

The clinical relevance of thrombophilia screening in stroke patients is still a matter of debate, and descriptions of larger patterns of genetic variability are rare. We assessed the frequency of hereditary hypercoagulability in young patients with cryptogenic stroke (n = 44) and in healthy blood donors (n = 282) without prior cardiovascular event. Furthermore, we focused on the impact of thrombophilia screening on secondary stroke prevention. Results: Compared to the control group (19–67 years; median 38.5 years; 64% women), there was a lower prevalence of the FVII-R353Q mutation (p = 0.033) in stroke patients (17–52 years; median 36 years; 59.1% women). Of note, the FVII-R353Q mutation lowers FVII plasma levels, probably reducing the risk of cardiovascular events. The prevalence of the remaining 13 gene polymorphisms did not differ significantly. However, the prevalence of FV Leiden mutation tended to be higher among stroke patients. Conclusion: Overall, extended screening for inherited thrombophilia had an impact on medical stroke prevention in every sixth patient with cryptogenic stroke.

The β-fibrinogen gene 455G/A polymorphism associated with cardioembolic stroke in atrial fibrillation with low CHA2DS2-VaSc score

Previous work has suggested that ischemic stroke (IS) may be more likely to occur in individuals with a genetic predisposition. In this study, we investigated the potential association of IS-relevant genetic risk factors with cardioembolic stroke (CES) in atrial fibrillation (AF) patients with low CHA2DS2-VaSc score. Genotyping was performed using the GenomeLab SNPstream genotyping platform for five IS-relevant SNPs (MMP-9 C1562T, ALOX5AP SG13S114A/T, MTHFR 677 C/T, FGB 455 G/A, and eNOS G298A) in 479 AF patients with CES and 580 age and sex-matched AF patients without CES. The multivariate analysis adjusted for potential confounders and demonstrated that FGB 455 G/A was independently associated with increased risk of CES in AF patients and the significance remained after Bonferroni correction in the additive, dominant, and recessive models with ORs of 1.548 (95% CI: 1.251–1.915, P = 0.001), 1.588 (95% CI: (1.226–2.057, P = 0.003), and 2.394 (95% CI: 1.357–4.223, P = 0.015), respectively. Plasma fibrinogen levels were significantly higher in patients with the A allele compared with patients with genotype of GG (3.29 ± 0.38 mg/dl vs. 2.87 ± 0.18 mg/dl, P < 0.001). We found for the first time that the A allele of FGB 455 G/A was a risk factor for CES in AF patients, probably by elevating the level of plasma fibrinogen.

The role of fibrinogen plasma levels, the –455G>A fibrinogen and the factor XIII A subunit (FXIII-A) Val34Leu polymorphism in cancer-associated venous thrombosis

Venous thromboembolism (VTE) is a life-threatening complication in cancer patients. Identification of risk factors has been in focus in the past years. Functional single nucleotide polymorphisms (SNP) of coagulation factors known to influence the concentration or function may be considered to influence the risk of VTE in cancer patients. We evaluated the influence of fibrinogen plasma levels, the –455G>A SNP in the fibrinogen beta gene and the Val34Leu (163G>T) SNP in the factor XIII A-subunit (FXIII-A) gene on the risk of VTE. In 1,079 tumour patients recruited for the prospective Vienna Cancer and Thrombosis Study (CATS) fibrinogen levels were determined by the Clauss method. The FXIII-A Val34Leu and the fibrinogen –455G>A SNPs were tested by allele-specific PCR. The median follow-up time was 604 days, 83 thrombotic events occurred. The median fibrinogen level was 381 mg/dl (25th-75th percentile: 312 to 467). In a multivariable Cox model adjusted to chemotherapy, surgery, radiotherapy, age and sex, neither the fibrinogen concentration (hazard ratio [HR] =1.05, confidence interval [CI] 0.839–1.310 p=0.68), nor the –455G>A SNP (HR=0.77, 95%CI 0.491–1.197; p=0.24), nor the Val34Leu SNP (HR=0.99, 95%CI 0.646–1.542 p=0.99) were associated with occurrence of VTE. The fibrinogen concentration was not significantly different among the fibrinogen –455G or A genotype carriers (p = 0.33). Disseminated intravascular coagulation was observed in only five patients, none of these developed VTE. In conclusion, fibrinogen plasma levels, the fibrinogen –455G>A and the FXIII-A Val34Leu polymorphisms were not associated with VTE in our study.

Fibrinogen consumption is related to intracranial clot burden in acute ischemic stroke: a retrospective hyperdense artery study

Background

Understanding the underlying mechanism of thrombus formation and its components is critical for effective prevention and treatment of ischemic stroke. The generation of thrombotic clots requires conversion of soluble fibrinogen to an insoluble fibrin network. Quantitative features of intracranial clots causing acute ischemic stroke can be studied on non-contrast enhanced CT (NECT). Here, we evaluated on-admission fibrinogen and clot burden in relation to stroke severity, final infarct volume and in-hospital mortality.

Methods

We included 132 consecutive patients with ischemic stroke and presence of hyperdense artery sign admitted within 6 h from symptom onset. Radiological parameters including clot area (corresponding to clot burden) and final infarct volume were manually determined on NECT. National Institute of Health Stroke Scale (NIHSS) was used to quantify disease severity and short-term outcome.

Results

Median patient age was 77, 58 % were women, and 63 % had an occlusion of the proximal middle cerebral artery segment. Thrombolysis was performed in 60 % and thrombectomy in 44 %. We identified several independent associations. Higher fibrinogen levels on admission were associated with smaller clot burden (p = 0.033) and lower NIHSS on admission (p = 0.022). Patients with lower fibrinogen had a higher clot burden (p = 0.028) and greater final infarct volume (p = 0.003). Higher fibrinogen was associated with a lower risk of in-hospital death or NIHSS score >15 if discharged alive (p = 0.028).

Conclusions

Our study suggests that intracranial clot burden in acute ischemic stroke is associated with fibrinogen consumption, and shows a complex relationship with disease severity, infarct size and in-hospital survival.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1006-6) contains supplementary material, which is available to authorized users.

Ischemic Stroke and Six Genetic Variants in CRP, EPHX2, FGA, and NOTCH3 Genes: A Meta-Analysis

BACKGROUND

Ischemic stroke (IS) is a leading cause of death and disability worldwide. As genetic heritability for IS is estimated at about 35%-40%, the identification of genetic variants associated with IS risk is of great importance. The main objective of this study was to carry out a meta-analysis for polymorphisms in CRP, EPHX2, FGA, and NOTCH3 genes and the risk for IS.

METHODS

Literature search for 6 candidate polymorphisms and IS was conducted using HuGE Navigator, PubMed, and Google Scholar databases. Meta-Analyst program was used to calculate pooled odds ratios (ORs) with a random effects model.

RESULTS

Twenty-five published studies for 6 candidate polymorphisms were included: CRP-rs1800947 (5 studies), CRP-rs1205 (3 studies), EPHX2-rs751141 (5 studies), FGA-rs6050 (6 studies), NOTCH3-rs3815188 (3 studies), and NOTCH3-rs1043994 (3 studies), for a total number of 7,825 IS cases and 56,532 control subjects. We did not find significant pooled ORs (P values > .05) for any of the genetic variants evaluated in this work.

CONCLUSIONS

Our meta-analysis results did not show significant associations between these 6 polymorphisms in 4 candidate genes and IS, despite the functional role of some of these single nucleotide polymorphisms (e.g., rs6050 in FGA gene). Future studies are needed to identify additional main genetic risk factors for IS in different populations.

Variants of the Coagulation and Inflammation Genes Are Replicably Associated with Myocardial Infarction and Epistatically Interact in Russians

Background

In spite of progress in cardiovascular genetics, data on genetic background of myocardial infarction are still limited and contradictory. This applies as well to the genes involved in inflammation and coagulation processes, which play a crucial role in the disease etiopathogenesis.

Methods and Results

In this study we found genetic variants of TGFB1, FGB and CRP genes associated with myocardial infarction in discovery and replication groups of Russian descent from the Moscow region and the Republic of Bashkortostan (325/185 and 220/197 samples, correspondingly). We also found and replicated biallelic combinations of TGFB1 with FGB, TGFB1 with CRP and IFNG with PTGS1 genetic variants associated with myocardial infarction providing a detectable cumulative effect. We proposed an original two-component procedure for the analysis of nonlinear (epistatic) interactions between the genes in biallelic combinations and confirmed the epistasis hypothesis for the set of alleles of IFNG with PTGS. The procedure is applicable to any pair of logical variables, e.g. carriage of two sets of alleles. The composite model that included three single gene variants and the epistatic pair has AUC of 0.66 both in discovery and replication groups.

Conclusions

The genetic impact of TGFB1, FGB, CRP, IFNG, and PTGS and/or their biallelic combinations on myocardial infarction was found and replicated in Russians. Evidence of epistatic interactions between IFNG with PTGS genes was obtained both in discovery and replication groups.

Hypercoagulability and the risk of myocardial infarction and ischemic stroke in young women

BACKGROUND

Myocardial infarction (MI) and ischemic stroke (IS) are acute forms of arterial thrombosis and share some, but not all, risk factors, indicating different pathophysiological mechanisms.

OBJECTIVE

This study aims to determine if hypercoagulability has a differential effect on the risk of MI and IS.

PATIENTS AND METHODS

We reviewed the results from the Risk of Arterial Thrombosis in Relation to Oral Contraceptives study, a population-based case-control study involving young women (< 50 years) with MI, non-cardioembolic IS and healthy controls. From these data, relative odds ratios (ORIS /ORMI ) and their corresponding confidence intervals for all prothrombotic factors that were studied in both subgroups were calculated.

RESULTS

Twenty-nine prothrombotic risk factors were identified as measures of hypercoagulability. Twenty-two of these risk factors (21/29, 72%) had a relative odds ratios > 1; for 12 (41%), it was > 2; and for 5 (17%), it was > 2.75. The five risk factors with the largest differences in associations were high levels of activated factor XI (FXI) and FXII, kallikrein, the presence of lupus anticoagulans, and a genetic variation in the FXIII gene.

CONCLUSION

In young women, prothrombotic factors are associated more with the risk of IS than with MI risk, suggesting a different role of hypercoagulability in the mechanism leading to these two diseases.

Hypofibrinogenemia and the α-Fibrinogen Thr312Ala Polymorphism may be Risk Factors for Early Pregnancy Loss

We analyzed a cohort of 36 females with pregnancy loss. In addition to 11 patients with antiphospholipid antibody syndrome and 2 patients with congenital antithrombin (AT) or protein C deficiency, we identified 5 patients with low fibrinogen levels (median 110 mg/dL) prior to 10 weeks of gestation. Four of these 5 patients underwent a fibrinogen gene analysis, and all 4 were found to be heterozygotes for the α-fibrinogen (FGA) Thr321Ala polymorphism. One female without hypofibrinogenemia with a history of 8 pregnancy losses was found to be homozygous for the same polymorphism, and she also showed hypercoagulability without thrombosis. In conclusion, there was a relatively high frequency of pregnancy loss in the setting of hypofibrinogenemia and/or the FGA Thr312Ala polymorphism, and this may be an important risk factor for pregnancy loss and a hypercoagulable state in later pregnancy.

Biomarkers for arterial and venous thrombotic disorders

The haemostatic system maintains the blood in a fluid state, but allows rapid clot formation at sites of vascular injury to prevent excessive bleeding. Unbalances within the haemostatic system can lead to thrombosis. Inspite of successful research our understanding of the disease pathogenesis is still incomplete. There is great hope that genetic, genomic, and epigenetic discoveries will enhance the diagnostic capability, and improve the treatment options. During the preceding 20 years, the identification of polymorphisms and the elucidation of their role in arterial and venous thromboses became an important area of research. Today, a large body of data is available regarding associations of single nucleotide polymorphisms (SNPs) in candidate genes with plasma concentrations and e. g. the risk of ischaemic stroke or myocardial infarction. However, the results for individual polymorphisms and genes are often controversial. It is now well established that besides acquired also hereditary risk factors influence the occurrence of thrombotic events, and environmental factors may add to this risk. Currently available statistical methods are only able to identify combined risk genotypes if very large patient collectives (>10,000 cases) are tested, and appropriate algorithms to evaluate the data have yet to be developed. Further research is needed to understand the functional effects of genetic variants in genes of blood coagulation proteins that are critical to the pathogenesis of arterial and venous thrombotic disorders. In this review genetic variants in selected genes of the haemostatic system and their relevance for arterial and venous thrombosis will be discussed.

Fibrinogen alpha and beta gene polymorphisms in pediatric stroke--case-control and family based study

BACKGROUND/PURPOSE

Data on the role of the -455G > A polymorphism of the gene encoding β fibrinogen subunit (FGB) and the Thr312Ala polymorphism of the gene for the α fibrinogen subunit (FGA) in childhood ischemic stroke are insufficient. Therefore the aim of the study was to evaluate a possible association between these two polymorphisms and arterial ischemic stroke.

METHODS

The study group consisted of 85 children after ischemic stroke, 146 of their parents and 159 controls. Both polymorphisms were genotyped using the restriction fragment length polymorphism method. Two study designs were used: a case-control model and a family-based transmission-disequilibrium test. Statistica 7.1 and EpiInfo 6 softwares were used in all analyses.

RESULTS

In the TDT test, a tendency to a higher transmission of the 312Ala allele of the FGA gene and the -455A allele of the FGB gene was observed, however, it was statistically non-significant. The frequencies of alleles and genotypes of both FGA and FGB genes polymorphisms did not differentiate children from both groups also in the case-control model. Additive or synergistic effects between FGA and FGB genes polymorphisms were not observed.

CONCLUSION

An analysis of the results obtained in this study and a critical review of previously published data indicate that examined gene polymorphisms are not related to ischemic stroke in children.

The role of hs-CRP, D-dimer and fibrinogen in differentiating etiological subtypes of ischemic stroke

The aim of this study was to evaluate the diagnostic value of the serum biochemical markers high-sensitivity C-reactive protein (hs-CRP), D-dimer (DD) and fibrinogen (Fg) in differentiating etiological subtypes of ischemic stroke. This study was a retrospective case-only study, consecutively including patients with acute ischemic stroke. All patients were classified into subtypes using the TOAST classification system. A total of 317 patients were evaluated. Hs-CRP and DD levels were significantly different among the subtypes and were the highest in CE, followed by LAA and SAA; no significant difference between the subtypes was found for Fg. Hs-CRP > 6.96 mg/L was classified as the CE subtype, with a sensitivity of 41% and a specificity of 74%; DD > 791.30 ng/mL was classified as CE, with a sensitivity of 58% and a specificity of 78%. The combination of hs-CRP and DD classification as CE yielded a sensitivity of 65% and a specificity of 91%. DD > 791.30 ng/mL was considered an independent predictive factor of CE. Hs-CRP and DD could be useful for identifying the etiological subtypes of acute ischemic stroke, especially for predicting CE. The diagnostic value of DD was higher than that of hs-CRP.

A polymorphism (-455G>A) in the β-fibrinogen gene is associated with an increased risk of cerebral infarction in the Chinese population: A meta-analysis

BACKGROUND

Previous studies have investigated the association between a polymorphism (-455 G>A) in the β-fibrinogen gene and the risk of cerebral infarction. However, these results are controversial. To shed light on these inconclusive findings, we performed a meta-analysis of studies relating the β-fibrinogen genetic polymorphism (-455 G>A) to the risk of cerebral infarction.

METHODS

We identified literature published before July 2013 by searching PubMed, EMBASE, ISI Web of Science, the Chinese National Knowledge Infrastructure database (CNKI) and the Wanfang database in China and by reviewing the references of retrieved articles. We included studies that reported odds ratio (OR) with 95% confidence interval (CI) for the association between the β-fibrinogen genetic polymorphism and cerebral infarction risk. Publication bias was tested by a funnel plot, and the OR of all studies were combined dependent on the results of the heterogeneity tests among the individual studies. The software Review Manager (Version 5.2) was used for meta-analysis.

RESULTS

Twenty independent case-control studies containing 9477 subjects were included. Our results showed that the -455 G>A polymorphism in the β-fibrinogen gene was associated with the increased risk of cerebral infarction [(AA+GA) vs. GG, OR=1.17, 95%CI: 1.04-1.31, p=0.008; A vs. G, OR=1.12, 95%CI: 1.01-1.23, p=0.03] in the Chinese population by a meta-analysis. However, we did not find this association in the Caucasian population [(AA+GA) vs. GG, OR=0.99, 95%CI: 0.87-1.11, p=0.84; A vs. G, OR=0.97, 95%CI: 0.84-1.13, p=0.73, respectively].

CONCLUSION

The results of our meta-analysis indicate that the -455 G>A polymorphism in the β-fibrinogen gene is a susceptibility marker of ischemic cerebral infarction in the Chinese population.

Fibrinogen and factor XIII at the intersection of coagulation, fibrinolysis and inflammation

Fibrinogen and factor XIII are two essential proteins that are involved directly in fibrin gel formation as the final step of a sequence of reactions triggered by a procoagulant stimulus. Haemostasis is the most obvious function of the resulting fibrin clot. Different variables affect the conversion of fibrinogen to fibrin as well as the mode of fibrin polymerisation and fibrin crosslinking, hereby, critically influencing the architecture of the resulting fibrin network and consequently determining its mechanical strength and resistance against fibrinolysis. Due to fibrinogen's structure with a multitude of domains and binding motifs the fibrin gel allows for complex interactions with other coagulation factors, with profibrinolytic as well as antifibrinolyic proteins, with complement factors and with various cellular receptors. These interactions enable the fibrin network to control its own further state (i. e. expansion or degradation), to influence innate immunity, and to function as a scaffold for cell migration processes. During the whole process of fibrin gel formation biologically active peptides and protein fragments are released that additionally influence cellular processes via chemotaxis or by modulating cell-cell interactions. Thus, it is not surprising that fibrinogen and factor XIII in addition to their haemostatic function influence innate immunity as well as cell-mediated reactions like wound healing, response to tissue injury or inflammatory processes. The present review summarises current knowledge of fibrinogen's and factor XIII's function in coagulation and fibrinolysis giving special emphasis on their relation to inflammation control.

Integrative computational and experimental approaches to establish a post-myocardial infarction knowledge map

Vast research efforts have been devoted to providing clinical diagnostic markers of myocardial infarction (MI), leading to over one million abstracts associated with “MI” and “Cardiovascular Diseases” in PubMed. Accumulation of the research results imposed a challenge to integrate and interpret these results. To address this problem and better understand how the left ventricle (LV) remodels post-MI at both the molecular and cellular levels, we propose here an integrative framework that couples computational methods and experimental data. We selected an initial set of MI-related proteins from published human studies and constructed an MI-specific protein-protein-interaction network (MIPIN). Structural and functional analysis of the MIPIN showed that the post-MI LV exhibited increased representation of proteins involved in transcriptional activity, inflammatory response, and extracellular matrix (ECM) remodeling. Known plasma or serum expression changes of the MIPIN proteins in patients with MI were acquired by data mining of the PubMed and UniProt knowledgebase, and served as a training set to predict unlabeled MIPIN protein changes post-MI. The predictions were validated with published results in PubMed, suggesting prognosticative capability of the MIPIN. Further, we established the first knowledge map related to the post-MI response, providing a major step towards enhancing our understanding of molecular interactions specific to MI and linking the molecular interaction, cellular responses, and biological processes to quantify LV remodeling.

Heart attack, known medically as myocardial infarction, often occurs as a result of partial shortage of blood supply to a portion of the heart, leading to the death of heart muscle cells. Following myocardial infarction, complications might arise, including arrhythmia, myocardial rupture, left ventricular dysfunction, and heart failure. Although myocardial infarction can be quickly diagnosed using a various number of tests, including blood tests and electrocardiography, there have been no available prognostic tests to predict the long-term outcome in response to myocardial infarction. Here, we present a framework to analyze how the left ventricle responds to myocardial infarction by combining protein interactome and experimental results retrieved from published human studies. The framework organized current understanding of molecular interactions specific to myocardial infarction, cellular responses, and biological processes to quantify left ventricular remodeling process. Specifically, our knowledge map showed that transcriptional activity, inflammatory response, and extracellular matrix remodeling are the main functional themes post myocardial infarction. In addition, text analytics of relevant abstracts revealed differentiated protein expressions in plasma or serum expressions from patients with myocardial infarction. Using this data, we predicted expression levels of other proteins following myocardial infarction.

Influence of the β-fibrinogen-455G/A polymorphism on development of ischemic stroke and coronary heart disease

BACKGROUND

Ischemic stroke (IS) and coronary heart disease (CHD) are two vascular disorders that are a common cause of death worldwide. Several studies have assessed the association of the β-fibrinogen-455G/A (FGB-455G/A) polymorphism and risk of IS and CHD, but the results are still inconsistent. Our study aimed to investigate whether the FGB-455G/A polymorphism was associated with susceptibility to IS and CHD by using meta-analysis.

METHODS

Relevant studies were identified from PubMed, Embase and four Chinese database up to July 2013.Data were analyzed and processed by Stata 11.2. A pooled OR with 95% CI was calculated to estimate the strength of the genetic association. Cumulative meta-analysis was performed to assess the tendency of pooled OR over time.

RESULTS

45 studies based on a total of 7238 cases and 7395 controls were included in our meta-analysis. The results indicated that the FGB-455G/A polymorphism is associated with the risk of IS when compared with the dominant model (OR=1.518, 95%CI=1.279-1.802 for AA+GA vs. GG). In the subgroup analysis by ethnicity, significantly elevated risks were associated with the A allele in Asians (OR=1.700, 95%CI=1.417-2.040), but not in Caucasians (OR=0.942, 95%CI=0.813-1.091). Both the hypertension and non-hypertension subgroups reached significant results, but no significance was found when stratified according to sex or subtype of IS. Results indicate that the FGB-455G/A polymorphism is associated with CHD (OR=1.802, 95%CI=1.445-2.246).

CONCLUSION

Our meta-analysis suggests that the FGB-455G/A polymorphism contributes to susceptibility to IS and CHD.

Genetic polymorphism of β-fibrinogen gene-455G/A can contribute to the risk of ischemic stroke

Many studies have investigated the association between the β-fibrinogen gene-455G/A (FGβ-455G/A) polymorphism and the risk of ischemic stroke. However, these evidences were inadequate to provide stronger conclusions because most studies were generally small. To shed light on these inconclusive findings, we conducted a large sample size meta-analysis of studies relating to the FGβ-455G/A polymorphism and the risk of ischemic stroke. Odds ratios with a 95 % confidence interval were used to investigate the association between FGβ-455G/A polymorphism and ischemic stroke. Publication bias was tested by Egger's test and funnel plot. Inconsistency index and Cochran's Q statistic were used to check heterogeneity. Cumulative and recursive cumulative meta-analyses were performed to provide a framework for updating a genetic effect from all of the included studies. Twenty-six independent publications with 4,070 cases and 4,649 controls were included in this meta-analysis. Results showed that the β-fibrinogen-455G/A polymorphism was significantly associated with the risk of ischemic stroke. The FGβ-455G/A polymorphism was found to be a risk factor for ischemic stroke in Asians and adults, while association was not observed for Caucasians and juveniles based on the small size and it may be necessary to conduct larger studies on them to investigate the association in the future. The cumulative meta-analysis indicated a decline from 1998 to 2003, and the results remained stable during the period 2004-2012. The results indicate that FGβ-455G/A polymorphism may be a susceptible predictor of ischemic stroke. More studies are needed to elucidate the relationship further.

GNB3, eNOS, and mitochondrial DNA polymorphisms correlate to natural longevity in a Xinjiang Uygur population

BACKGROUND

In centenarian populations, application of the positive biology approach (examination of positive phenotypes in aging) has revealed that mitochondrial DNA (mtDNA) mutation accumulation may be linked to human longevity; however, the role of guanine nucleotide-binding protein (G protein) abnormalities modulated by G-protein beta-3 (GNB3) and nitrate (NO2) production associated with endothelial nitric oxide synthase (eNOS), commonly appearing in age-related diseases, remains undetermined.

OBJECTIVE

The association between the mtDNA 5178A/C, mtDNA 10398A/G, GNB3 C825T, and eNOS polymorphisms and longevity in a Uygur population (Xinjiang region, China) were investigated.

METHODS

A total of 275 experimental subjects aged ≥ 100 or with 4 generations currently living were screened for inclusion in the centenarian (>100 years) and nonagenarian groups (90-100 years), and 112 65-70 year old control subjects were selected. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to examine mtDNA 5178A/C, mtDNA 10398A/G, GNB3 C825T, and eNOS. Associations between polymorphic loci, genotypes, and longevity were analyzed.

RESULTS

165 included subjects (M∶F = 107∶58; mean age = 97 ± 3 years; mean age 100-113 years) were assigned to the centenarian (M∶F = 46/19; n = 65) and nonagenarian groups (M∶F = 61/39; n = 100). Associations between mtDNA C5178A and A10398G polymorphisms with longevity in the centenarian group with mtDNA genotype frequencies 5178A and 10398G were 66.79% and 36.8%.

CONCLUSIONS

Applying the overwhelming longevity observed in Uygur populations, these findings demonstrate that mtDNA 5178A/C and 10398A/G, GNB3 C825T, and eNOS polymorphisms are useful as a genetic basis for longevity.

Fibrinogen Aα Thr312Ala polymorphism specifically contributes to chronic thromboembolic pulmonary hypertension by increasing fibrin resistance

Background

Polymorphisms are associated with chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary thromboembolism (PTE), but no polymorphism specific to CTEPH but not PTE has yet been reported. Fibrin resistance is associated with CTEPH, but the mechanism has not been elucidated.

Methods

Polymorphisms were analyzed in 101 CTEPH subjects, 102 PTE subjects and 108 healthy controls by Massarray or restriction fragment length polymorphism (RFLP). Plasmin-mediated cleavage of fibrin was characterized in 69 subjects (29 with CTEPH, 21 with PTE and 19 controls).

Results

Genotype frequencies and allele frequencies of fibrinogen Aα Thr312Ala were significantly higher in CTEPH subjects than in controls and PTE subjects, while there was no difference between PTE subjects and controls. The odd ratio (OR 2.037) and 95% confidence interval (95% CI, 1.262–3.289) showed that Thr312Ala polymorphism was a risk factor for CTEPH but not PTE. Fibrin from CTEPH subjects was more resistant to lysis than that from PTE subjects and controls. Fibrin resistance was significantly different between Aα Thr312Ala (A/G) genotypes within CTEPH subjects, and the fibrin with GG genotype was more resistant than that with AA and AG genotype.

Conclusions

Fibrinogen Aα Thr312Ala (A/G) polymorphism was associated with CTEPH, but not PTE, suggesting that the fibrinogen Aα Thr312Ala polymorphism may act as a potential biomarker in identifying CTEPH from PTE. GG genotype polymorphism contributes to CTEPH through increasing fibrin resistance, implying that PTE subjects with fibrinogen Aα GG genotype may need long-term anticoagulation therapy.

Circulating biomarkers for predicting cardiovascular disease risk; a systematic review and comprehensive overview of meta-analyses

BACKGROUND

Cardiovascular disease is one of the major causes of death worldwide. Assessing the risk for cardiovascular disease is an important aspect in clinical decision making and setting a therapeutic strategy, and the use of serological biomarkers may improve this. Despite an overwhelming number of studies and meta-analyses on biomarkers and cardiovascular disease, there are no comprehensive studies comparing the relevance of each biomarker. We performed a systematic review of meta-analyses on levels of serological biomarkers for atherothrombosis to compare the relevance of the most commonly studied biomarkers.

METHODS AND FINDINGS

Medline and Embase were screened on search terms that were related to "arterial ischemic events" and "meta-analyses". The meta-analyses were sorted by patient groups without pre-existing cardiovascular disease, with cardiovascular disease and heterogeneous groups concerning general populations, groups with and without cardiovascular disease, or miscellaneous. These were subsequently sorted by end-point for cardiovascular disease or stroke and summarized in tables. We have identified 85 relevant full text articles, with 214 meta-analyses. Markers for primary cardiovascular events include, from high to low result: C-reactive protein, fibrinogen, cholesterol, apolipoprotein B, the apolipoprotein A/apolipoprotein B ratio, high density lipoprotein, and vitamin D. Markers for secondary cardiovascular events include, from high to low result: cardiac troponins I and T, C-reactive protein, serum creatinine, and cystatin C. For primary stroke, fibrinogen and serum uric acid are strong risk markers. Limitations reside in that there is no acknowledged search strategy for prognostic studies or meta-analyses.

CONCLUSIONS

For primary cardiovascular events, markers with strong predictive potential are mainly associated with lipids. For secondary cardiovascular events, markers are more associated with ischemia. Fibrinogen is a strong predictor for primary stroke.

Circulating biomarkers for predicting cardiovascular disease risk; a systematic review and comprehensive overview of meta-analyses

BACKGROUND

Cardiovascular disease is one of the major causes of death worldwide. Assessing the risk for cardiovascular disease is an important aspect in clinical decision making and setting a therapeutic strategy, and the use of serological biomarkers may improve this. Despite an overwhelming number of studies and meta-analyses on biomarkers and cardiovascular disease, there are no comprehensive studies comparing the relevance of each biomarker. We performed a systematic review of meta-analyses on levels of serological biomarkers for atherothrombosis to compare the relevance of the most commonly studied biomarkers.

METHODS AND FINDINGS

Medline and Embase were screened on search terms that were related to "arterial ischemic events" and "meta-analyses". The meta-analyses were sorted by patient groups without pre-existing cardiovascular disease, with cardiovascular disease and heterogeneous groups concerning general populations, groups with and without cardiovascular disease, or miscellaneous. These were subsequently sorted by end-point for cardiovascular disease or stroke and summarized in tables. We have identified 85 relevant full text articles, with 214 meta-analyses. Markers for primary cardiovascular events include, from high to low result: C-reactive protein, fibrinogen, cholesterol, apolipoprotein B, the apolipoprotein A/apolipoprotein B ratio, high density lipoprotein, and vitamin D. Markers for secondary cardiovascular events include, from high to low result: cardiac troponins I and T, C-reactive protein, serum creatinine, and cystatin C. For primary stroke, fibrinogen and serum uric acid are strong risk markers. Limitations reside in that there is no acknowledged search strategy for prognostic studies or meta-analyses.

CONCLUSIONS

For primary cardiovascular events, markers with strong predictive potential are mainly associated with lipids. For secondary cardiovascular events, markers are more associated with ischemia. Fibrinogen is a strong predictor for primary stroke.

Coagulation and the fibrin network in rheumatic disease: a role beyond haemostasis

Activation of the immune system has been increasingly recognised to be associated with procoagulatory status in patients with inflammatory rheumatic disease. Changes in endothelial cell and platelet activation, blood flow, expression and activity of different coagulation factors, and impaired fibrinolysis serve as pathophysiological basis for enhanced risk of venous thromboembolism in inflammatory rheumatic diseases, such as rheumatoid arthritis (RA), connective tissue diseases and vasculitides. Recent studies identifying mechanisms for a functional role of coagulation factors beyond haemostasis have provided examples of interesting links between the coagulation system and innate immune activation. Furthermore, citrullinated fibrinogen is an important and early autoantigen in patients with RA carrying the HLA-DRβ1 shared epitope allele, which demonstrates an adaptive immune response to a coagulation factor in an inflammatory rheumatic disease. Additional studies have provided strong evidence that a multitude of different components of the haemostatic system (such as thrombin, fibrinogen, coagulation factor XIII and factors of the fibrinolytic system) are relevant mediators of inflammatory processes as well as of inflammatory control. Understanding the interactions between coagulation and the immune system in inflammatory rheumatic diseases will not only improve our knowledge of disease mechanisms, but could also permit the development of innovative therapeutic interventions.

Are centenarians genetically predisposed to lower disease risk?

Our study purpose was to compare a disease-related polygenic profile that combined a total of 62 genetic variants among (i) people reaching exceptional longevity, i.e., centenarians (n = 54, 100-108 years, 48 women) and (ii) ethnically matched healthy controls (n = 87, 19-43 years, 47 women). We computed a 'global' genotype score (GS) for 62 genetic variants (mutations/polymorphisms) related to cardiometabolic diseases, cancer or exceptional longevity, and also specific GS for main disease categories (cardiometabolic risk and cancer risk, including 36 and 24 genetic variations, respectively) and for exceptional longevity (7 genetic variants). The 'global' GS was similar among groups (centenarians: 31.0 ± 0.6; controls 32.0 ± 0.5, P = 0.263). We observed that the GS for hypertension, cancer (global risk), and other types of cancer was lower in the centenarians group compared with the control group (all P < 0.05), yet the difference became non significant after adjusting for sex. We observed significant between-group differences in the frequency of GSTT1 and GSTM1 (presence/absence) genotypes after adjusting for multiple comparisons. The likelihood of having the GSTT1 low-risk (functional) allele was higher in centenarians (odds ratio [OR] 5.005; 95% confidence interval [CI], 1.810-13.839), whereas the likelihood of having the GSTMI low-risk (functional) allele was similar in both groups (OR 1.295; 95% CI, 0.868 -1.931). In conclusion, we found preliminary evidence that Spanish centenarians have a lower genetic predisposition for cancer risk. The wild-type (i.e., functional) genotype of GSTT1, which is associated with lower cancer risk, might be associated with exceptional longevity, yet further studies with larger sample sizes must confirm these findings.

Candidate gene polymorphisms and the risk for pregnancy-related venous thrombosis

Venous thrombosis (VT) is one of the leading causes of maternal death in the western world, but the genetic causes of pregnancy-related VT are insufficiently understood. The aim of this study was to investigate the association between common genetic variations in candidate genes and pregnancy-related VT. We undertook a hospital based case-control study of women with VT during pregnancy or puerperium; controls were women giving birth without having VT. Single nucleotide polymorphisms (SNPs) were selected in 49 pre-specified candidate genes involved in coagulation, inflammation, and hormonal metabolism in 313 cases and 353 controls. We found new associations between SNPs and total pregnancy-related VT in the genes encoding coagulation factors V and VIII, and p-selectin. Additional new associations between SNPs and antenatal VT were found in the genes encoding the epidermal growth factor receptor, the pregnane X receptor, and protein S. Of 21 SNPs previously associated with thrombotic disease, rs2289252 in F11 and rs3917643 in F3 were associated with pregnancy-related VT, while rs4524 in F5 was associated with antenatal VT.

Fibrinogen polymorphisms associated with sporadic cerebral hemorrhage in a Chinese population

Fibrinogen plays an important role in the intrinsic and extrinsic pathways of blood coagulation. This study investigated the association between common variants in the fibrinogen gene and the risk of developing sporadic cerebral hemorrhage (CH). We performed genotyping analyses for three single nucleotide polymorphisms (SNP) in the fibrinogen gene in a case-controlled study involving 195 patients with CH and 116 control participants; both groups were of southern Han-Chinese origin. Logistic regression analysis indicated that haplotypes ATA (rs1800790+rs1800787+rs6050), AA (rs1800790+rs6050) and TA (rs1800787+rs6050) could nearly double the risk of sporadic CH (odds ratio [OR]=1.738, 95% confidence interval [CI]: 1.103-2.740, p=0.017; adjusted OR=1.762, 95% CI: 1.042-2.982, p=0.035), although the three SNP were not associated with sporadic CH when analyzed separately. These findings indicate that rs1800790, rs1800787 and rs6050 polymorphisms may contribute to the etiology of sporadic CH in the Chinese population.

Replication and characterisation of genetic variants in the fibrinogen gene cluster with plasma fibrinogen levels and haematological traits in the Third National Health and Nutrition Examination Survey

Previous genetic association studies of the fibrinogen gene cluster have identified associations with plasma fibrinogen levels. These studies are typically limited to plasma fibrinogen measured among European-descent populations. We sought to replicate previous well-known associations with fibrinogen variants and plasma fibrinogen. We then sought to identify and characterise novel associations with fibrinogen variants with plasma fibrinogen and several haematological traits in three racial/ethnic populations. We genotyped 25 single nucleotide polymorphisms (SNPs) in the fibrinogen gene cluster in 2,631 non-Hispanic whites, 2,108 non-Hispanic blacks, and 2,073 Mexican-Americans from the Third National Health and Nutrition Examination Survey (NHANES). We performed single SNP tests of association for plasma fibrinogen, mean platelet volume, platelet distribution width, platelet count, white blood cell count, and serum triglycerides. Five previously identified associations with plasma fibrinogen replicated in our study in non-Hispanic whites and blacks. We identified two novel associations between genetic variants and decreased plasma fibrinogen: rs2227395 (p=0.0007; non-Hispanic whites) and rs2070022 (p=0.001; Mexican-Americans). Several fibrinogen SNPs were also associated with haematological traits: rs6050 with decreased platelet distribution width in non-Hispanic whites; rs6050 and rs2066879 with decreased and increased platelet distribution width, respectively, in non-Hispanic whites;rs2227409 with increased mean platelet volume, rs2070017 with decreased platelet count, and rs6063 with increased platelet distribution width in non-Hispanic blacks; and rs4220 and rs2227395 with decreased white blood cell count, rs2227409 with increased platelet distribution width, rs2066860 and rs1800792 with increased and decreased triclyceride levels, respectively, and rs1800792 with decreased platelet counts in Mexican-Americans. We successfully replicated and identified novel associations with fibrinogen variants and plasma fibrinogen. These data confirm the importance of the fibrinogen gene cluster for plasma fibrinogen levels as well as suggest this gene cluster may have pleiotropic effects on haematological traits.

Significant associations of the rs2943634 (2q36.3) genetic polymorphism with adiponectin, high density lipoprotein cholesterol and ischemic stroke

BACKGROUND

rs2943634 C/A single nucleotide polymorphism (SNP), located in a non coding region of chromosome 2q36.3, has been associated with coronary artery disease in two genome wide association studies. Our goal was to investigate its relation with myocardial infarction (MI) and ischemic stroke (IS), as well as with 12 intermediate risk phenotypes, in a population-based prospective cohort study.

METHODS

rs2943634 was genotyped in a case-cohort study including a random sample of 1891 individuals (subcohort) and all incident MI (n=211) and IS (n=144) cases during a mean follow-up of 8.2±2.2years, nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort comprising 27,548 middle-aged men and women.

RESULTS

rs2943634 minor allele (A) was associated in an additive fashion with lower risk of IS but not with MI [hazard ratio (HR)=0.66; 95% confidence interval (CI): 0.50-0.87; P=0.003; HR=1.02; 95% CI: 0.82-1.28; P=0.83 respectively, for the age and sex adjusted model]. Furthermore, it was related to slightly higher levels of plasma adiponectin [CC 6.94, CA 7.27, AA 7.86μg/ml, P=0.0002] and high density lipoprotein (HDL)-cholesterol (CC 52.08, CA 53.05 and AA 55.27mg/dl, P=0.002), based on additive models. Adjustment for adiponectin and HDL-cholesterol did not attenuate the association between the SNP and IS risk. In contrast, adjustment for adiponectin abolished the association between the SNP and HDL-cholesterol and adjustment for HDL-cholesterol attenuated the association between the SNP and adiponectin.

CONCLUSIONS

Our findings suggest that rs2943634 is associated with IS risk and with plasma levels of HDL-cholesterol and adiponectin in this German population. Further investigations are needed to confirm these results and to clarify the mechanisms underlying the association.

Fibrinogen and cardiovascular disease: genetics and biomarkers

Several prospective epidemiological studies and clinical observations provided evidence regarding fibrinogen and coronary artery disease (CAD). Many of these studies firmly correlate fibrinogen with CAD. However, it is uncertain whether this relation is causal or reflects genetic variability and residual confounding by other risk factors. Several polymorphisms on fibrinogen chain genes affect its levels, however only few of the genetic variants are associated with increased cardiovascular risk. As regards the role of fibrinogen in myocardial infarction (MI) studies indicate that genetic variations have at best a modest impact on the process resulting in MI. Therefore, the screening of fibrinogen genes might not be useful for the assessment of the risk of MI. However, the findings that specific genotypes lead to specific differences in fibrinogen levels, but may not be linked to cardiovascular risk, complicates the hypothesis of causality of fibrinogen in the pathogenesis of cardiovascular disease.

Screening for coagulation disorders in patients with ischemic stroke

The role of coagulation disorders in the pathogenesis of (recurrent) ischemic stroke is uncertain. Therefore, the clinical utility of screening patients with ischemic stroke for these conditions and the therapeutic implications of a detected coagulation disorder in a patient who experienced ischemic stroke are uncertain. We reviewed the currently available data on the relationship between various inherited and acquired coagulation abnormalities (factor V Leiden and prothrombin G20210A mutations, deficiencies of protein C, protein S and anti-thrombin, hyperhomocysteinemia, the antiphospholipid syndrome and increased levels of fibrinogen) and ischemic stroke. Based on the existing evidence we discuss the usefulness of screening stroke patients for prothrombotic conditions and current recommendations regarding the optimal management of ischemic stroke patients in whom a coagulation disorder is found.

Association of genomic loci from a cardiovascular gene SNP array with fibrinogen levels in European Americans and African-Americans from six cohort studies: the Candidate Gene Association Resource (CARe)

Several common genomic loci, involving various immunity- and metabolism-related genes, have been associated with plasma fibrinogen in European Americans (EAs). The genetic determinants of fibrinogen in African Americans (AAs) are poorly characterized. Using a vascular gene-centric array in 23,634 EA and 6657 AA participants from 6 studies comprising the Candidate Gene Association Resource project, we examined the association of 47,539 common and lower frequency variants with fibrinogen concentration. We identified a rare Pro265Leu variant in FGB (rs6054) associated with lower fibrinogen. Common fibrinogen gene single nucleotide polymorphisms (FGB rs1800787 and FGG rs2066861) significantly associated with fibrinogen in EAs were prevalent in AAs and showed consistent associations. Several fibrinogen locus single nucleotide polymorphism associated with lower fibrinogen were exclusive to AAs; these include a newly reported association with FGA rs10050257. For IL6R, IL1RN, and NLRP3 inflammatory gene loci, associations with fibrinogen were concordant between EAs and AAs, but not at other loci (CPS1, PCCB, and SCL22A5-IRF1). The association of FGG rs2066861 with fibrinogen differed according to assay type used to measure fibrinogen. Further characterization of common and lower-frequency genetic variants that contribute to interpopulation differences in fibrinogen phenotype may help refine our understanding of the contribution of hemostasis and inflammation to atherothrombotic risk.

High platelet reactivity is associated with myocardial infarction in premenopausal women: a population-based case-control study

SUMMARY BACKGROUND

Platelets are involved in the occlusion of coronary arteries after rupture of an atherosclerotic plaque. Furthermore, activated platelets release large quantities of growth factors, chemokines and interleukins that regulate inflammatory reactions. Therefore, we hypothesized that high basal platelet reactivity may contribute to an increased risk of myocardial infarction (MI) in premenopausal women.

METHODS

We assessed the relation between high platelet reactivity and MI in a population-based case-control study among premenopausal women (aged < 50 years). We used multivariable logistic regression to quantify the effect of high platelet reactivity, adjusted for potential confounders. Platelet reactivity was estimated by plasma levels of neutrophil activating peptide 2 (NAP-2), CXC chemokine ligand (CXCL)4, soluble glycoprotein 1b (sGPIb) and soluble P-selectin.

RESULTS

High platelet reactivity (i.e. levels >or= 90th percentile control subjects) was associated with a 2- to 3-fold increased incidence of MI: the adjusted odds ratios (ORs) were 3.0 [95% confidence interval (CI) 1.4-6.4] for NAP-2, 2.2 (0.9-5.1) for CXCL4, 1.9 (0.7-4.6) for sP-selectin and 2.5 (1.1-5.7) for sGPIb. The incidence of MI dose-dependently increased when more markers were elevated. High platelet reactivity according to both NAP-2 and sGPIb was associated with an up to tenfold increased incidence (9.9, 95% confidence interval 2.0-48.3).

CONCLUSIONS

High basal platelet reactivity was associated with a 2- to 3-fold higher incidence of MI compared with normal platelet reactivity in premenopausal women. Our results suggest that high basal platelet reactivity may contribute to a higher risk of MI.