Combined effect of hemostatic gene polymorphisms and the risk of myocardial infarction in patients with advanced coronary atherosclerosis

Acute Myocardial Infarction in Patients with Hereditary Thrombophilia-A Focus on Factor V Leiden and Prothrombin G20210A

Factor V (FV) Leiden and prothrombin G20210A are the most common hereditary thrombophilias. While their role in venous thromboembolism is well known, there are still uncertainties regarding their relationship with arterial thrombotic events, especially coronary ones. Our research, based on an in-depth analysis of the available literature, provides up-to-date information on the relationship between FV Leiden and prothrombin G20210A and acute myocardial infarction. FV Leiden and prothrombin G20210A screening should be implemented only in select cases, such as acute coronary syndrome in young individuals and/or in the absence of traditional cardiovascular risk factors and/or in the absence of significant coronary artery stenosis at angiography. Their identification should be followed by the implementation of optimal control of modifiable traditional cardiovascular risk factors to reduce the risk of recurrent events and genotyping and genetic counseling of all family members of affected cases for proper prophylaxis. An extended dual antiplatelet therapy (DAPT) may be considered, given the lower risk of bleeding under DAPT conferred by FV Leiden.

Association between P2Y1 and P2Y12 polymorphisms and acute myocardial infarction and ADP-induced platelet aggregation

BACKGROUND

The objective of this study was to investigate the relationship between P2Y1 and P2Y12 genotypes and the risk of acute myocardial infarction (AMI) in the Quanzhou population and to determine associations between P2Y1 and P2Y12 genotypes and ADP-induced platelet aggregation in this population.

METHODS

All subjects were screened for P2Y1 (c.1622A > G) and P2Y12 (H1/H2, c.34C > T) polymorphisms by direct DNA sequencing. The maximal platelet aggregation rate (MAR) in AMI patients (n = 61) and healthy control subjects (n = 50) was measured by a PL-12 platelet function analyzer, and adenosine diphosphate (ADP) (5 μmol/L) was used as an agonist.

RESULTS

The haploid H2 allele in the P2Y12 gene was more frequent in patients with AMI than in control subjects (OR 1.887, P = 0.005). The P2Y12 H2 haplotype was significantly associated with AMI in the codominant (P = 0.008), dominant (OR 2.103, P = 0.003), and overdominant models (OR 2.133, P = 0.003). After adjusting for potential confounders, H2 haplotype carriers had a 2.132-fold increased risk for AMI (OR 2.132, P = 0.012) compared with noncarriers. Moreover, we observed that the ADP-induced MAR in the carriers of the H2 haplotype from the control group was somewhat higher than that in noncarriers of this group (P = 0.020). However, we failed to demonstrate that the P2Y1 H1/H2 polymorphism affected ADP-induced MAR in AMI patients. Additionally, P2Y1 c.1622A > and P2Y12 c.34C > T polymorphisms were not associated with the risk of AMI or ADP-induced MAR in either group.

CONCLUSIONS

Therefore, our results suggest that the P2Y12 H2 haplotype was associated with a higher risk of AMI, while its effect on increased ADP-induced platelet aggregation remains to be investigated. Thus, the P2Y12 H2 haplotype may be a potential marker for AMI.

Plasminogen Activator Inhibitor-1 Polymorphisms and Risk of Coronary Artery Disease: Evidence From Meta-Analysis and Trial Sequential Analysis

A systematic review and meta-analysis were conducted to find out if there was association between Plasminogen Activator Inhibitor-1 (PAI-1) gene polymorphisms (- 844 G > A and - 675 4G > 5G) and susceptibility to coronary artery disease (CAD). Search of electronic databases was performed and the pooled odds ratio (OR) and 95% confidence interval (CI) were exerted to evaluate the pooled association between the single-nucleotide polymorphisms (SNPs) and risk of CAD. For - 675 4G > 5G SNP, dominant (OR = 0.90), recessive (OR = 0.90), allelic (OR = 0.91), homozygous (OR = 0.84), and heterozygous (OR = 0.96) models were significantly associated with decreased risk of CAD. Moreover, all five genetic models were associated significantly with decreased CAD risk in the Causation and Arab populations. The results in Asians were marginally significant in recessive, allelic, and homozygote models. The male gender was found to be a risk factor in individuals with PAI-1 4G > 5G SNP in the dominant model (OR = 0.89), recessive model (OR = 0.91), allelic model (OR = 0.92), homozygous model (OR = 0.86), and heterozygous model (OR = 0.91). The results of pooled ORs for overall populations and subgroup analysis by ethnicity reject any association between PAI-1 gene - 844 G > A polymorphism and CAD risk under all genetic comparisons. The results of this meta-analysis indicated that PAI-1 4G > 5G SNP was associated with decreased risk of CAD in the overall population as well as in the Asians, Caucasians, and Arab populations. However, the PAI-1 gene - 844 G > A polymorphism had no significant association with susceptibility to CAD.

Coagulation Factor XIII Val34Leu Polymorphism in the Prediction of Premature Cardiovascular Events-The Results of Two Meta-Analyses

Background: Polymorphisms within the gene that encodes for coagulation factor XIII (FXIII) have been suggested to be involved in the pathogeneses of ischemic stroke (IS) and myocardial infarction (MI). The Val34Leu polymorphism is one of the most commonly analysed FXIII polymorphisms. However, studies on the role of the Val34Leu polymorphism in the aetiology of vascular diseases often show contradictory results. In the present meta-analysis, we aimed to pool data from available articles to assess the relationship between the FXIII Val34Leu polymorphism and the susceptibilities to IS of undetermined source and premature MI in patients aged below 55 years. Methods: We searched databases (PubMed, Embase, Google Scholar, SciELO, and Medline) using specific keywords (the last search was in January 2022). Eventually, 18 studies (627 cases and 1639 controls for IS; 2595 cases and 4255 controls for MI) met the inclusion criteria. Data were analysed using RevMan 5.4 and StatsDirect 3 link software. The relation between Val34Leu polymorphism and disease was analysed in five genetic models, i.e., dominant, recessive, additive, heterozygous, and allelic. Results: No relation between Val34Leu polymorphism and IS in young adults was observed in all analysed genetic models. For premature MI, significant pooled OR was found between the carrier state of the Leu allele (Val/Leu + Leu/Leu vs. Val/Val) and a lack of MI, suggesting its protective role (OR = 0.80 95%CI 0.64–0.99, p = 0.04). A similar finding was observed for the heterozygous model in MI (Val/Leu vs. Val/Val) (OR = 0.77 95%CI 0.61–0.98, p = 0.03). No relation was found for the recessive, additive, and allelic models in MI. Conclusions: In the population of young adults, no positive correlation was found between the FXIII Val34Leu polymorphism and IS of undetermined source in any of the analysed genetic models. In turn, the carrier state of the 34Leu allele as well as FXIII heterozygotes themselves were found to play a protective role in relation to premature MI.

Fibrinogen β chain and FXIII polymorphisms affect fibrin clot properties in acute pulmonary embolism

BACKGROUND

Prothrombotic fibrin clot properties, including increased clot density, are in part genetically determined. We investigated whether fibrinogen alpha-chain gene (FGA) c.991A>G (rs6050), fibrinogen beta chain gene (FGB) -455G>A (rs1800790) and factor XIII gene (F13) c.103G>T (rs5985) polymorphisms affect plasma fibrin clot properties in patients with acute pulmonary embolism (PE).

METHODS

As many as 126 normotensive patients with PE, free of cancer, were genotyped by TaqMan assay. Fibrin clot permeability (K_s ), clot lysis time (CLT) and endogenous thrombin potential (ETP) were assessed on admission.

RESULTS

The minor allele frequencies were as follows: FGA rs6050 (n = 62, 0.31), FGB rs1800790 (n = 40, 0.17) and F13 rs5985 (n = 49, 0.23). There were no differences related to any of the polymorphisms with regard to demographic, clinical and laboratory data, except for fibrinogen concentration, which was higher in carriers of F13 rs5985 polymorphism (p = .024), and PE combined with deep-vein thrombosis, which was less prevalent in FGB rs1800790 polymorphism carriers (p = .004). Carriers of FGB rs1800790 A allele and F13 rs5985 T allele had lower K_s , prolonged CLT and higher ETP compared with major homozygotes (all p < .05). After adjustment for fibrinogen, all differences remained significant (all p < .01). There were no associations between the FGA rs6050 polymorphism and K_s , CLT or ETP.

CONCLUSION

Our study showed that FGB rs1800790 and F13 rs5985 polymorphisms contribute to the prothrombotic fibrin clot phenotype and these effects are strong enough to be observed in the acute phase of PE.

Genetic polymorphisms in early-onset myocardial infarction in a sample of Iraqi patients: a pilot study

OBJECTIVES

Early-onset myocardial infarction constitutes nearly one third of cases of myocardial infarction among Iraqis, which is rather higher than the proportions reported in many Western countries. Thus this study was initiated to investigate the role of some genetic polymorphisms, as well as acquired risk factors in this condition.

RESULTS

A total of 102 Iraqi patients with first myocardial infarction aged 50 years, and 77 matched controls were enrolled. The DNAs of participants were screened for nine polymorphisms, namely: β-Fibrinogen (- 455G > A), Factor XIII (V34L), Plasminogen Activator inhibitor-1 (PAI-1, 4G/5G), Human Platelet Antigen-1 (HPA1a/b), 5,10-Methylenetetrahydrofolate Reductase MTHFR (C677T) and MTHFR (A1298C), Angiotensin-Converting Enzyme (ACE) 287 bp insertion/deletion (I/D), Apolipoprotein-B (ApoB: R3500Q), and Apolipoprotein-E (Apo E: E2/E3/E4), using PCR and reverse hybridization technique. Among traditional risk factors, univariate analysis revealed that smoking (OR 2.86 [95%CI 1.53-5.34]), hyperlipidemia (OR 5.23 [95%CI 2.66-10.29]), and diabetes mellitus (OR 4.05 [95% CI 1.57-10.41]) were significantly higher among patients compared to controls (P<0.001, <0.001 and 0.002 respectively), while none of the nine genetic polymorphisms reached significance. Multivariate Logistic regression, however, revealed that only smoking and hyperlipidemia retained significance (P of < 0.001 each). The need to initiate further studies on larger cohorts is paramount to understand the higher than expected frequency of early-onset myocardial infarction in our population.

Molecular assessment of some cardiovascular genetic risk factors among Iraqi patients with ischemic heart diseases

OBJECTIVE

The underlying molecular basis of ischemic heart diseases (IHDs) has not yet been studied among Iraqi people. This study determined the frequency and types of some cardiovascular genetic risk factors among Iraqi patients with IHDs.

METHODS

This is a cross-sectional study recruiting 56 patients with acute IHD during a 2-month period excluding patients >50 years and patients with documented hyperlipidemia. Their ages ranged between 18 and 50 years; males were 54 and females were only 2. Peripheral blood samples were aspirated from all patients for troponin I and DNA testing. Molecular analysis to detect 12 common cardiovascular genetic risk factors using CVD StripAssay^® (ViennaLab Diagnostics GmbH, Austria) was performed.

RESULTS

The genotype frequencies of 12 genetic mutations/polymorphisms were as follows: MTHFR A1298C and C677T were the highest reported mutations (62.5% and 50%, respectively), followed by β-fibrinogen gene mutation, homozygous angiotensin-converting enzyme D/D, heterozygous human platelet antigen-1(a/b) polymorphisms, plasminogen activator inhibitor-1 4G/4G, homozygous E4 allele of apolipoprotein E gene, Leu allele of Factor XIII V34L variant, heterozygous FV R2, Factor V Leiden mutation, prothrombin G20210A mutation, respectively. Genetic risk scores were calculated and a number ranging from 0 to 8 were given to each patient. None (0%) had a risk score >6 or <2; 22 (39.3%) patients had a risk score of 4 and >60% of cases had a risk score of 4 or more.

CONCLUSION

The obtained results constitute a reference guide where future studies on normal people and older IHD patients can rely on to determine whether these can be used for pre-clinical risk assessment.

Association of FV G1691A Polymorphism but not A4070G With Coronary Artery Disease

Coronary artery disease (CAD) is one of the chief causes of death in the world. Several hypotheses have been promoted as for the origin of the disease, among which are genetic predispositions and/or environmental factors. The aim of this study was to determine the effect of factor V (FV) gene polymorphisms (Leiden, G1691A [FVL] and HR2 A4070G) and to analyze their association with traditional risk factors in assessing the risk of CAD. Our study population included 200 Tunisian patients with symptomatic CAD and a control group of 300 participants matched for age and sex. All participants were genotyped for the FVL and HR2 polymorphisms. Multivariate logistic regression was applied to analyze independent factors associated with the risk of CAD. Our analysis showed that the FVL A allele frequency (P < 10^–3, odds ratio [OR] = 2.81, 95% confidence interval [CI] = 1.6-4.9) and GA genotype (P < 10^–3, OR = 4.03, 95% CI = 2.1-7.6) are significantly more prevalent among patients with CAD compared to those controls and may be predisposing to CAD. We further found that the FVL mutation is an independent risk factor whose effect is not modified by other factors (smoking, diabetes, hypertension, dyslipidemia, and a family history of CAD) in increasing the risk of the disease. However, analysis of FV HR2 variation does not show any statistically significant association with CAD. The FVL polymorphism may be an independent risk factor for CAD. However, further investigations on these polymorphisms and their possible synergisms with traditional risk factors for CAD could help to ascertain better predictability for CAD susceptibility.

Prothrombin G20210A (rs1799963) polymorphism increases myocardial infarction risk in an age-related manner: A systematic review and meta-analysis

G20210A polymorphism (rs1799963) within the prothrombin gene is associated with a higher circulation level of prothrombin, thus increasing the likelihood of developing myocardial infarction (MI). Opinions differ regarding the correlation between prothrombin G20210A genotype and MI risk, which prompted us to conduct a meta-analysis to determine this association. PubMed, EMBASE, Web of Science and CNKI were searched for pertinent reports. A total of 34 studies involving 14 611 MI cases and 84 358 controls were analyzed in this quantitative analysis. We found a statistically significant association between prothrombin G20210A polymorphism and MI in the allele model (A vs. G, OR = 1.43, 95%CI: 1.18–1.72), heterozygote model (GA vs. GG, OR = 1.41, 95%CI: 1.16–1.72) and dominant model (GA + AA vs. GG, OR = 1.41, 95%CI: 1.15–1.72). The association remains significant in Caucasians but not in non-Caucasians. Moreover, prothrombin G20210A polymorphism increases MI risk in an age-related manner. A further significant association was found in a subpopulation younger than 55 years (allele model, OR = 1.76, 95%CI: 1.32–2.35; heterozygote model, OR = 1.70, 95%CI: 1.24–2.33; dominant model, OR = 1.70, 95%CI: 1.24–2.34). Sensitivity analysis and publication bias analysis revealed stable and statistically robust results. Our meta-analysis demonstrated that prothrombin G20210A polymorphism may represent a risk factor for MI.

Association of genetic variants of hemostatic genes with myocardial infarction in Egyptian patients

Hemostatic genes polymorphisms are well known to be associated with venous thrombosis, but their association with arterial thrombosis especially myocardial infarction (MI) remains to be clarified. We investigated the role of three hemostatic gene polymorphisms, prothrombin G20210A, factor XIII (FXIII) Val34Leu (G/T), and fibrinogen-β-455G/A and their coexistence in Egyptian patients with MI. The possible correlation of these polymorphisms with plasma fibrinogen level was also evaluated. The study included 120 patients with MI and 60 healthy volunteers. Gene polymorphisms were tested using multiplex polymerase chain reaction and reverse-hybridization technique. Plasma fibrinogen level was determined by ELISA. Our study showed an increased risk of MI with fibrinogen β-455G/A heterozygosity as well as FXIII Val34Leu homo and heterozygosity. In addition, the FXIII T allele (Leu34) and fibrinogen β-455A allele were significantly associated with MI. Conversely, the prevalence of prothrombin mutation did not differ between patients with MI and controls. Combined carriers of FXIII Leu34 and fibrinogen-β455A alleles were at higher risk of MI, whereas combined FXIII Val34Leu and prothrombin 20210A polymorphisms did not show increased risk for MI compared with controls. Plasma fibrinogen levels were significantly higher in patients with MI than controls. In MI patients, plasma fibrinogen levels were significantly higher in those with FXIII GT/TT or fibrinogen β-455 GA, while were significantly lower in those with prothrombin 20210 GA compared with patients with wild type genotypes. In conclusion, our results suggest a possible thrombotic predisposition of FXIII Val34Leu, fibrinogen β-455G/A polymorphisms and their coexistence for MI. These polymorphisms may add complexity to disease pathology by increasing plasma fibrinogen level. Extended studies are needed to confirm our results; nevertheless, these data may be implicated in genetic counseling and screening of high-risk individuals.

Frequency of single nucleotide platelet receptor gene polymorphism (P2Y12-i744T>C) in coronary artery disease patients among Tamilian population

Several factors contribute to the development of coronary artery disease (CAD). Adenosine diphosphate (ADP) activated P2Y12 receptor also plays a key role in platelet activation and aggregation. It has been found that common variation in the P2Y12 gene was associated with increased platelet aggregation resulting in adverse cardiovascular outcomes. Thus, polymorphisms in the ADP receptor P2Y12 may contribute to the development of CAD. This study aims to determine the frequency distribution of platelet receptor polymorphism P2Y12 (i744T>C) in Tamilian population and to predict its possible role in CAD. Three hundred seventy-one subjects were recruited comprising of 221 healthy volunteers and 150 patients with CAD belonging to either sex, aged 18-60 years of Tamilian origin. Genomic DNA was extracted using phenol-chloroform method. Genotyping was done by PCR-RFLP (Polymerase chain reaction-restriction fragment length polymorphism). The C allele frequency of P2Y12 polymorphism in controls and cases was 8.4% and 17.7%, respectively. The TT, TC, and CC genotype frequencies in controls and cases were 83.7%, 15.8%, 0.5% and 66.7%, 31.3%, 2%, respectively. The genotype frequencies were in Hardy-Weinberg equilibrium. There was a significant association (p < 0.05) between the mutant genotypes of P2Y12 (i744T>C) polymorphism  and risk of CAD. The odds ratio was found to be 2.6. The variant allele frequency of P2Y12-i744T>C was significantly different from other populations. There was a significant association between the mutant genotypes of P2Y12 (i744T>C) polymorphism  and risk of developing CAD. Thus, the present study will emphasize on the relevance of pharmacogenetic testing of P2Y12 (i744T>C)  receptor gene polymorphism in CAD patients.

Thrombomodulin gene proximal promoter polymorphisms in premature acute coronary syndrome patients in Bahrain

Thrombomodulin is expressed on endothelial cells and monocytes (mTM) where it has an anticoagulant function. Enzymatic cleavage from the cell surface produces soluble thrombomodulin (sTM) in plasma. Abnormal levels of sTM and mutations in the thrombomodulin gene (THBD) are linked to cardiovascular disease. The aim of this study was to investigate THBD proximal promoter mutations and levels of sTM and mTM in men presenting with premature acute coronary syndrome (ACS). This prospective cross-sectional study included 100 adult men with premature ACS (age <55 years) and 60 healthy age-matched controls. Plasma sTM was assayed by ELISA. mTM expression was assessed by flow cytometry with CD141 antibody. The -33 G/A polymorphism was identified by PCR-restriction fragment length polymorphism analysis and the THBD proximal promoter region was sequenced. Significantly lower sTM (P < 0.001) and higher mTM (P < 0.001) were seen in ACS patients. Heterozygous THBD promoter polymorphisms -33 G/A and -9/-10 GG/AT were found in eight patients and five control individuals. In patients and control individuals, allele frequencies of A were 0.02 and 0.025, and that of AT were 0.025 and 0.017, respectively. There were no significant associations of these polymorphisms with ACS, sTM levels or mTM expression. THBD polymorphisms -33 G/A and -9/-10 GG/AT are present in low frequency in our patient population, and are more frequent in the South Asians as compared to the Arabs. The frequency of -33 G/A is lower, whereas that of -9/-10 GG/AT is higher than that reported in the Orientals. The presence of THBD proximal promoter polymorphisms do not explain variations in levels of sTM and mTM in this patient population.

Effect of genetic variation in P2Y12 on TRAP-stimulated platelet response in healthy subjects

In platelets, thrombin receptor signaling depends upon the release of adenosine diphosphate and subsequent activation at purinergic subtype Y (P2Y) receptors. The purpose of this study is to evaluate the influence of specific P2Y12 polymorphisms on platelet reactivity in healthy subjects mediated by thrombin receptor activating peptide (TRAP). We recruited a total of 29 healthy volunteers who had been previously genotyped for two polymorphisms of the P2Y12 receptor: the H2 haplotype (rs2046934) and 34C>T (rs6785930). Flow cytometry and the VerifyNow assay were used to assess platelet activation and aggregation stimulated by TRAP in the presence and absence of specific receptor antagonists for the P2Y1, P2Y12, and thromboxane A2 receptors. We identified a significant recessive effect of the P2Y12-receptor H2 haplotype on TRAP-induced flow cytometry. Specifically, H2/H2 carriers (n = 5) demonstrated a significant reduction in both glycoprotein IIb/IIIa receptor activation (p < 0.001) and CD62P expression (p = 0.035). While the VerifyNow assay did not reveal any effect of haplotype on TRAP-mediated platelet aggregation (p = 0.72), the H2/H2 subjects demonstrated greater platelet inhibition in the presence of cangrelor, a specific receptor antagonist for the P2Y12 receptor (p = 0.023). No consistent effects of the separate 34C>T genotype (rs6785930) were demonstrated under the conditions evaluated. The findings of this study suggest a potential association between P2Y12-receptor H2/H2 carriers and reduced platelet function mediated by TRAP in healthy volunteers.

Where genotype is not predictive of phenotype: towards an understanding of the molecular basis of reduced penetrance in human inherited disease

Some individuals with a particular disease-causing mutation or genotype fail to express most if not all features of the disease in question, a phenomenon that is known as 'reduced (or incomplete) penetrance'. Reduced penetrance is not uncommon; indeed, there are many known examples of 'disease-causing mutations' that fail to cause disease in at least a proportion of the individuals who carry them. Reduced penetrance may therefore explain not only why genetic diseases are occasionally transmitted through unaffected parents, but also why healthy individuals can harbour quite large numbers of potentially disadvantageous variants in their genomes without suffering any obvious ill effects. Reduced penetrance can be a function of the specific mutation(s) involved or of allele dosage. It may also result from differential allelic expression, copy number variation or the modulating influence of additional genetic variants in cis or in trans. The penetrance of some pathogenic genotypes is known to be age- and/or sex-dependent. Variable penetrance may also reflect the action of unlinked modifier genes, epigenetic changes or environmental factors. At least in some cases, complete penetrance appears to require the presence of one or more genetic variants at other loci. In this review, we summarize the evidence for reduced penetrance being a widespread phenomenon in human genetics and explore some of the molecular mechanisms that may help to explain this enigmatic characteristic of human inherited disease.

The impact of blood coagulability on atherosclerosis and cardiovascular disease

Although the link between blood coagulation and atherogenesis has been long postulated, only recently, and through the extensive work on transgenic mice, crossbred on an atherogenic background, has the direction of this interaction become visible. In general, hypercoagulability in mice tends to increase atherosclerosis, whereas hypocoagulability reduces the atherosclerotic burden, depending on the mouse model used. The information on a direct relationship between coagulation and atherosclerosis in humans, however, is not that clear. Almost all coagulation proteins, including tissue factor, are found in atherosclerotic lesions in humans. In addition to producing local fibrin, a matrix for cell growth, serine proteases such as thrombin may be very important in cell signaling processes, acting through the activation of protease-activated receptors (PARs). Activation of PARs on vascular cells drives many complex processes involved in the development and progression of atherosclerosis, including inflammation, angiogenesis, and cell proliferation. Although current imaging techniques do not allow for a detailed analysis of atherosclerotic lesion phenotype, hypercoagulability, defined either by gene defects of coagulation proteins or elevated levels of circulating markers of activated coagulation, has been linked to atherosclerosis-related ischemic arterial disease. New, high-resolution imaging techniques and sensitive markers of activated coagulation are needed in order to study a causal contribution of hypercoagulability to the pathophysiology of atherosclerosis. Novel selective inhibitors of coagulation enzymes potentially have vascular effects, including inhibition of atherogenesis through attenuation of inflammatory pathways. Therefore, we propose that studying the long-term vascular side effects of this novel class of oral anticoagulants should become a clinical research priority.

Thrombin generation in type 2 diabetes with albuminuria and macrovascular disease

BACKGROUND

Albuminuria is an indicator of cardiovascular morbidity and mortality in patients with type 2 diabetic mellitus (T2DM).

MATERIALS AND METHODS

In our cross-sectional study, we measured thrombin generation (TG), a key process in haemostasis and a tool to detect an individual's coagulation potential, in normo-, micro- and macroalbuminuria in T2DM with and without macrovascular disease (MVD). The TG-assay was performed, and the TG-curve [including the lag phase, peak thrombin and area under the curve (AUC)] was analysed.

RESULTS

A total of 160 patients (62 women; mean age ± SD: 67 ± 11 years) with T2DM and normo-, micro- or macroalbuminuria were investigated. Of those, 90 (56%) patients had normoalbuminuria, 40 (25%) microalbuminuria and 30 (19%) macroalbuminuria. The AUC between the groups of patients with normo-, micro- and macroalbuminuria was statistically significantly different [3297 (2785; 3764) vs. 3222 (2381; 3678) vs. 3726 (3153; 4235) nM Thrombin; P = 0AE019]. T2DM patients with MVD (n = 121) had a significantly shorter lag phase [12 (9; 16) vs. 20 (15; 25) min; P < 0AE001], a significantly higher peak thrombin [233 (130; 339) vs. 133 (82; 187) nM; P < 0AE001] and a significantly higher AUC [3464 (2969; 3868) vs. 3091 (2384; 3619) nM Thrombin; P = 0AE01] than T2DM patients without MVD (n = 39), indicating an earlier and higher thrombin generation.

CONCLUSION

Our results support the hypothesis that TG may be involved in the pathogenesis of MVD in diabetic nephropathy as for the first time, we could show that patients with T2DM in different stages of diabetic nephropathy had disturbances in thrombin generation.

Aldose reductase C-106T gene polymorphism is associated with diabetic retinopathy in Japanese patients with type 2 diabetes

It is likely that the C allele of the polymorphism at position -106 in the promoter of aldose reductase gene, which codes a rate-limiting enzyme of the polyol pathway, is a susceptibility allele for diabetic retinopathy in Japanese type 2 diabetic patients.

Varied association of prothrombin G20210A polymorphism with coronary artery disease susceptibility in different ethnic groups: evidence from 15,041 cases and 21,507 controls

Published data on the association between prothrombin G20210A polymorphism and coronary artery disease (CAD) risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. A total of 42 case-control studies including 15,041 cases and 21,507 controls were included in this meta-analysis. Overall, significantly elevated CAD risk was associated with prothrombin G20210A polymorphism (OR, 1.22; 95% CI 1.07-1.40; P=0.003) when 39 eligible studies were pooled into the meta-analysis. In the subgroup analysis, borderline statistically increased risk was found for myocardial infarction in 22 case-control studies (OR, 1.27; 95% CI 1.00-1.61; P=0.05). When stratified by ethnicity, significantly elevated risk was found in Europeans (OR, 1.19; 95% CI, 1.02-1.38; P=0.02). However, no statistical differences were found among Americans and Asians. In summary, this meta-analysis indicated that prothrombin G20210A allele is a low-penetrant risk factor for developing CAD in Europeans.

Combined effect of inflammatory gene polymorphisms and the risk of ischemic stroke in a prospective cohort of subjects with type 2 diabetes: a Go-DARTS study

OBJECTIVE

We have previously observed that genetic profiles determined by the combination of five functionally significant single nucleotide polymorphisms (SNPs) (rs1800795, rs5498, rs5361, rs1024611, and rs679620) of genes encoding prototypical inflammatory molecules are associated with history of ischemic stroke. Here we tested the ability of this multigenic model to predict stroke risk in a large population-based prospective cohort of subjects with type 2 diabetes.

RESEARCH DESIGN AND METHODS

This study was conducted using a prospective cohort of individuals with type 2 diabetes participating in the Go-DARTS (Genetics of Diabetes Audit and Research in Tayside Scotland) study, which includes genetic and clinical information of patients with diabetes within the Tayside region of Scotland, U.K. The above-mentioned inflammatory SNPs were investigated in 2,182 Go-DARTS participants. We created an inflammatory risk score (IRS), ranging from 0 to 5, according to the number of "at-risk" genotypes concomitantly carried by a given individual. The primary outcome was the occurrence of fatal or nonfatal stroke of any kind. Mean follow-up time was 6.2 ± 1.1 years.

RESULTS

The incidence of stroke increased according to the IRS. The IRS was significantly and independently associated with increased stroke risk after adjustment for other conventional risk factors (hazard ratio 1.34 [95% CI 1.1-1.7]; P = 0.009). The highest hazard ratio for stroke was found in subjects concomitantly carrying > 3 proinflammatory variations and in subjects without previous cardiovascular diseases.

CONCLUSIONS

This large prospective cohort study provides evidence that SNPs of genes encoding prototypical inflammatory molecules may be used to create multigenic models that predict stroke risk in subjects with type 2 diabetes.

Apolipoprotein C-III predicts cardiovascular mortality in severe coronary artery disease and is associated with an enhanced plasma thrombin generation

BACKGROUND

Apolipopoprotein C-III (apo C-III) plays a pivotal role in controlling plasma triglyceride (TG) and contributes to the atherogenic properties of TG-rich lipoproteins.

OBJECTIVES

(i) To examine the predictive value of serum apo C-III for cardiovascular mortality in the setting of secondary prevention of coronary artery disease (CAD); and (ii) to evaluate possible associations between apolipoprotein levels and the thrombin generation assay, a global test to estimate plasma thrombogenic potential.

METHODS AND RESULTS

A cohort of 633 patients with angiographically proven CAD was prospectively followed for a median follow-up of 57 months. The large majority of them (92%) underwent coronary (endovascular or surgical) revascularization. During the follow-up, 91 (14.3%) out of 633 patients died, with 64 events (10.1%) attributed to cardiovascular causes. After adjustment for all the other predictors of mortality during univariate analysis (i.e. age, statin therapy, myocardial infarction history, diabetes, hs-CRP and creatinine), elevated apo C-III levels (> or = 10.5 mg dL(-1)- the median value) significantly predicted both total and cardiovascular mortality (HR for total mortality 2.22 with 95% CI 1.16-4.24; HR for cardiovascular mortality 2.35 with 95% CI 1.19-4.62). In a subgroup of 225 subjects, apo C-III levels were significantly associated with endogenous thrombin potential in regression models (standardized beta coefficient = 0.207, P = 0.002).

CONCLUSIONS

Basal concentrations of apo C-III levels > or = 10.5 mg dL(-1) in CAD patients independently predicted cardiovascular mortality during the subsequent 5-year period. Such concentrations were associated with an enhanced plasma endogenous thrombin generation, suggesting a complex interplay between TG-rich particles and the coagulation cascade as well as a new 'thrombogenetic' role for apo C-III.

Assessing the impact of a combined analysis of four common low-risk genetic variants on autism risk

Background

Autism is a complex disorder characterized by deficits involving communication, social interaction, and repetitive and restrictive patterns of behavior. Twin studies have shown that autism is strongly heritable, suggesting a strong genetic component. In other disease states with a complex etiology, such as type 2 diabetes, cancer and cardiovascular disease, combined analysis of multiple genetic variants in a genetic score has helped to identify individuals at high risk of disease. Genetic scores are designed to test for association of genetic markers with disease.

Method

The accumulation of multiple risk alleles markedly increases the risk of being affected, and compared with studying polymorphisms individually, it improves the identification of subgroups of individuals at greater risk. In the present study, we show that this approach can be applied to autism by specifically looking at a high-risk population of children who have siblings with autism. A two-sample study design and the generation of a genetic score using multiple independent genes were used to assess the risk of autism in a high-risk population.

Results

In both samples, odds ratios (ORs) increased significantly as a function of the number of risk alleles, with a genetic score of 8 being associated with an OR of 5.54 (95% confidence interval [CI] 2.45 to 12.49). The sensitivities and specificities for each genetic score were similar in both analyses, and the resultant area under the receiver operating characteristic curves were identical (0.59).

Conclusions

These results suggest that the accumulation of multiple risk alleles in a genetic score is a useful strategy for assessing the risk of autism in siblings of affected individuals, and may be better than studying single polymorphisms for identifying subgroups of individuals with significantly greater risk.