A combination of two common thrombomodulin gene variants (-1208-1209TTdelTT and A455V) influence risk of coronary heart disease: a prospective study in men

Single Nucleotide Polymorphisms in CD40L Predict Endothelial Complications and Mortality After Allogeneic Stem-Cell Transplantation

Purpose

Endothelial vulnerability is a potential risk factor for complications after allogeneic stem-cell transplantation (alloSCT). The CD40/CD40 ligand (CD40L) axis contributes to inflammatory diseases and is upregulated in endothelial cells upon activation, suggesting a role in alloSCT biology. Here, we studied single nucleotide polymorphisms (SNPs) in the CD40L gene in recipients of alloSCT.

Patients and Methods

Three CD40L SNPs (rs3092920, rs3092952, rs3092936) were analyzed for association with transplant-associated thrombotic microangiopathy, overall nonrelapse mortality (NRM), and NRM after acute graft-versus-host disease in 294 recipients of alloSCT without statin-based endothelial prophylaxis (SEP). The significant genotype was then put into perspective with established thrombomodulin ( THBD) gene polymorphisms. Findings were validated in an independent cohort without SEP and in an additional 344 patients who received SEP.

Results

The rs3092936 CC/CT genotype was associated with an increased risk of transplant-associated thrombotic microangiopathy ( P = .001), overall NRM ( P = .03), and NRM after acute graft-versus-host disease ( P = .01). The rs3092936 CC/CT genotype was largely mutually exclusive of high-risk THBD SNPs. Both CD40L and THBD SNPs predicted adverse overall survival (OS) and overall NRM to a similar extent in training cohort (OS, P = .04; NRM, P < .001) and validation cohort (OS, P = .01; NRM, P = .001) without SEP. In contrast, SEP completely abolished the influence of the high-risk CD40L and THBD SNPs ( P = .40).

Conclusion

An increased risk of endothelial complications can be predicted before alloSCT by genetic markers in the recipient’s genome. The normalization of mortality risks in patients treated with SEP suggests a way of overcoming the negative effect of high-risk genotypes and warrants further clinical validation.

Association of Thrombomodulin Gene Polymorphisms with Susceptibility to Atherosclerotic Diseases: A Meta-Analysis

Previous studies have proved that the dysfunction of thrombomodulin (TM) plays an important role in the pathogenesis of atherosclerotic diseases. In order to reveal their inherent relationship, we conducted a meta-analysis to uncover the association between two polymorphisms -33G/A and Ala455Val (c.1418C>T) in the TM gene and atherosclerotic diseases. We carried out a systematic search in PubMed, Science Direct, BIOSIS Previews, SpringerLink, the Cochrane library, the Chinese National Knowledge Infrastructure, the Chinese Biomedical Database, the Wei Pu database, and the Wanfang Database. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were computed to show the association. We included 22 eligible studies which involved 5472 patients and 7786 controls. There were statistically significant associations between -33G/A polymorphisms in TM and the MI group under the Allele and Recessive models in Asians (G vs. A: OR = 0.67, 95%CI = 0.56-0.78, P < 0.00001; GG vs. GA+AA: OR = 0.66, 95%CI = 0.56-0.78, P < 0.00001). However, these findings of the overall and subgroups showed that Ala455Val polymorphisms did not have any relationship with atherosclerotic diseases. After Bonferroni correction, the above associations remained statistically significant. This meta-analysis provides robust evidence of association between the -33G/A polymorphism in the TM gene and the risk of myocardial infarction in Asians. The A allele may increase the incidence of MI in Asians. However, the Ala455Val variant was not associated with atherosclerotic risk. Further studies with adequate sample size are needed to verify our findings.

Thrombomodulin -33G/A and Ala455Val polymorphisms are associated with the risk of coronary artery disease: a meta-analysis including 12 584 patients

BACKGROUND

Thrombomodulin (TM) -33G/A and Ala455Val polymorphisms have been indicated to be correlated with the risk of coronary artery disease (CAD), but study results are still inclusive. Thus, a meta-analysis was carried out.

MATERIALS AND METHODS

Databases including PubMed, Embase, CNKI, and Web of Science (ISI) were searched. Data were extracted and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Thirteen case-control studies on the relationship between TM -33G/A and Ala455Val polymorphisms and the risk of CAD were included in this meta-analysis. The association between the TM -33G/A polymorphism and the risk of CAD was significant (OR=1.65; 95% CI, 1.35-2.02; P<0.01; I(2)=15%). This result remained statistically significant when the adjusted ORs were combined (OR=1.50; 95% CI, 1.23-1.84; P<0.01; I(2)=0%). The association between the TM Ala455Val polymorphism and the risk of CAD was also significant (OR=1.14; 95% CI, 1.05-1.24; P<0.01; I(2)=0%). This result remained statistically significant when the adjusted ORs were combined (OR=1.57; 95% CI, 1.05-2.34; P=0.03; I(2)=32%).

CONCLUSION

This meta-analysis suggested that TM -33G/A and Ala455Val polymorphisms were risk factors for CAD.

Single-Nucleotide Polymorphisms Within the Thrombomodulin Gene (THBD) Predict Mortality in Patients With Graft-Versus-Host Disease

PURPOSE

Steroid-refractory graft-versus-host disease (GVHD) is a major and often fatal complication after allogeneic stem-cell transplantation (alloSCT). Although the pathophysiology of steroid refractoriness is not fully understood, evidence is accumulating that endothelial cell stress is involved, and endothelial thrombomodulin (THBD) plays a role in this process. Here we assess whether single-nucleotide polymorphisms (SNPs) within the THBD gene predict outcome after alloSCT.

PATIENTS AND METHODS

Seven SNPs within the THBD gene were studied (rs1962, rs1042579, rs1042580, rs3176123, rs3176124, rs3176126, and rs3176134) in a training cohort of 306 patients. The relevant genotypes were then validated in an independent cohort (n = 321).

RESULTS

In the training cohort, an increased risk of nonrelapse mortality (NRM) was associated with three of seven SNPs tested: rs1962, rs1042579 (in linkage disequilibrium with rs3176123), and rs1042580. When patients were divided into risk groups (one v no high-risk SNP), a strong correlation with NRM was observed (hazard ratio [HR], 2.31; 95% CI, 1.36 to 3.95; P = .002). More specifically, NRM was predicted by THBD SNPs in patients who later developed GVHD (HR, 3.03; 95% CI, 1.61 to 5.68; P < .001) but not in patients without GVHD. In contrast, THBD SNPs did not predict incidence of acute GVHD. Multivariable analyses adjusting for clinical variables confirmed the independent effect of THBD SNPs on NRM. All findings could be reproduced in the validation cohort.

CONCLUSION

THBD SNPs predict mortality of manifest GVHD but not the risk of acquiring GVHD, supporting the hypothesis that endothelial vulnerability contributes to GVHD refractoriness.

Association between thrombomodulin polymorphisms and coronary artery disease risk: a meta-analysis

Background

The associations between the thrombomodulin (TM) polymorphisms and coronary artery disease (CAD) risk remain controversial. The aim of this study was to evaluate the association of TM polymorphisms with CAD susceptibility using a meta-analysis approach.

Material/Methods

All eligible studies were identified through a search of PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI) before February 2014. The associations between the TM polymorphisms and CAD risk was assessed by odds ratios (ORs) and 95% confidence intervals (CIs).

Results

A total of 14 case-control studies, including 5493 cases and 8297 controls, were eventually collected. There was a significant association between TM -33G/A polymorphism and CAD risk (OR=1.61; 95% CI, 1.35–1.92; I²=15%). The TM Ala455Val polymorphism was also associated with a significantly increased CAD risk (OR=1.14; 95% CI, 1.05–1.24; I²=0%). These results remained statistically significant when the adjusted ORs were combined.

Conclusions

Our results suggest that TM-33G/A and Ala455Val polymorphisms are risk factors for CAD.

Association of the Thrombomodulin Gene c.1418C>T Polymorphism With Thrombomodulin Levels and With Venous Thrombosis Risk

Objective—

To investigate the association of the THBD c.1418C>T polymorphism, which encodes for the replacement of Ala455 by Val in thrombomodulin (TM), with venous thromboembolism (VTE), plasma soluble TM, and activated protein C levels. In addition, human umbilical vein endothelial cells (HUVEC) isolated from 100 umbilical cords were used to analyze the relation between this polymorphism and THBD mRNA and TM protein expression.

Approach and Results—

The THBD c.1418C>T polymorphism was genotyped in 1173 patients with VTE and 1262 control subjects. Levels of soluble TM and activated protein C were measured in 414 patients with VTE (not on oral anticoagulants) and 451 controls. HUVECs were genotyped for the polymorphism and analyzed for THBD mRNA and TM protein expression and for the ability to enhance protein C activation by thrombin. The 1418T allele frequency was lower in patients than in controls ( P <0.001), and its presence was associated with a reduced VTE risk, reduced soluble TM levels, and increased circulating activated protein C levels ( P <0.001). In cultured HUVEC, the 1418T allele did not influence THBD expression but was associated with increased TM in cell lysates, increased rate of protein C activation, and reduced soluble TM levels in conditioned medium.

Conclusions—

The THBD 1418T allele is associated with lower soluble TM, both in plasma and in HUVEC-conditioned medium, and with an increase in functional membrane–bound TM in HUVEC, which could explain the increased activated protein C levels and the reduced VTE risk observed in individuals carrying this allele.

Thrombomodulin and its role in inflammation

The goal is to provide an extensive review of the physiologic role of thrombomodulin (TM) in maintaining vascular homeostasis, with a focus on its anti-inflammatory properties. Data were collected from published research. TM is a transmembrane glycoprotein expressed on the surface of all vascular endothelial cells. Expression of TM is tightly regulated to maintain homeostasis and to ensure a rapid and localized hemostatic and inflammatory response to injury. By virtue of its strategic location, its multidomain structure and complex interactions with thrombin, protein C (PC), thrombin activatable fibrinolysis inhibitor (TAFI), complement components, the Lewis Y antigen, and the cytokine HMGB1, TM exhibits a range of physiologically important anti-inflammatory, anti-coagulant, and anti-fibrinolytic properties. TM is an essential cofactor that impacts on multiple biologic processes. Alterations in expression of TM and its partner proteins may be manifest by inflammatory and thrombotic disorders. Administration of soluble forms of TM holds promise as effective therapies for inflammatory diseases, and infections and malignancies that are complicated by disseminated intravascular coagulation.

Thrombomodulin gene polymorphisms and haplotypes and the risk of cardiovascular events: a prospective follow-up study

BACKGROUND

Thrombomodulin is an anticoagulant expressed during endothelial activation and damage. To address the potential role of allelic variants of thrombomodulin gene in the pathogenesis of cardiovascular diseases, we analyzed in a prospective follow-up study 8 single-nucleotide polymorphisms (SNPs) across the thrombomodulin locus, covering all common (>5%) haplotypes.

METHODS AND RESULTS

Two separate, stratified random samples of men and women 25 to 74 years of age were examined in Finland in 1992 and 1997. The total sample size was 14 140 individuals, with 7 (1997 cohort) to 10 (1992 cohort) years of follow-up. Altogether, 662 individuals had a history of cardiovascular events already at baseline. During the follow-up, 401 incident coronary events and 148 incident ischemic strokes were observed. The alleles and common haplotypes of 8 SNPs were tested in Cox proportional hazards models using incident coronary events, incident ischemic strokes, and total mortality as end points. None of the SNPs or major SNP haplotypes showed consistent association with the end points analyzed in the combined data.

CONCLUSIONS

Results from this prospective, population-based study suggest that common allelic variants of the thrombomodulin gene may not significantly contribute to the risk of cardiovascular events at the population level.