Thrombomodulin gene polymorphisms in brain infarction and mortality after stroke

Biochemical markers of thrombotic complications in the acute period of ischemic stroke

Aim. To study the profile of biochemical markers of the hemostasis system, to clarify their role and relationships in the pathogenesis of the development of thrombotic complications (TC) of ischemic stroke (IS) and the associated assessment of the possibilities of their diagnostic application. Materials and methods. The study group included 302 patients (164 men, 138 women) who were admitted to the hospital with a diagnosis of IS within 24 hours of the onset of the disease. The diagnosis was confirmed by computed tomography. The average age of patients was 69 (5088) years. Blood was taken from all patients on the 1st day of the disease to determine the profile of analytes presumably associated with the pathogenesis of TC. Levels of homocysteine, protein C inhibitor, thrombomodulin, plasminogen, tissue plasminogen activator, urokinase, plasminogen activator type 1 inhibitor, t-PA/PAI-1 complex, vitronectin, plasmin-2-antiplasmin complex, D-dimer, fibronectin were determined in blood serum by ELISA. Results. TC in the acute period of IS (up to 21 days) were recorded in 32 (10.6%, 95% CI 7.3714.3) patients, of which pulmonary embolism was observed in 27 (8.94%, 95% CI 5.9812.4) patients, deep vein thrombosis in 5 (1.66%, 95% CI 0.473.47) patients. The results of the study of a panel of specific proteins involved in pathogenetic processes accompanying necrosis of brain tissue in IS demonstrated that of the entire list of markers of the hemostasis system activation selected for the study, the most significant are: the concentration of fibronectin in the prognosis of the absence of TC with a threshold value of more than 61 mkg/ml and OR 4.4 (95% CI 1.512.9, p=0.011), and the concentration of the t-PA/PAI-1 complex in the prognosis of the development of TC with a threshold value of more than 14 ng/ml and OR 11.3 (95% CI 1.18109.3, p=0.03). Conclusion. The significance of the t-PA/PAI-1 complex and fibronectin as markers of TC in IS may be due to a violation of the activation processes of the fibrinolytic link of hemostasis and the accumulation of non-deposited compounds that damage the vascular wall.

Thrombomodulin and High-Sensitive C-Reactive Protein Levels in Blood Correlate with the Development of Cerebral Infarction Among Asians

Our meta-analysis was designed to obtain the correlation between thrombomodulin (TM) and high-sensitive C-reactive protein (hs-CRP) levels and the development of cerebral infarction (CI). Case-control studies relevant to the role plasma TM levels and serum hs-CRP levels in the development of CI were retrieved both electronically and manually and further screened according to a predetermined inclusion and exclusion criteria. All enrolled studies were analyzed for meta-regression analyses, sensitivity analyses, and assessments of publication bias. Comprehensive Meta-analysis 2.0 software (CMA 2.0) was used for statistical analysis. A total of 359 studies were initially retrieved, and 13 studies were eventually recruited into our meta-analysis with a total of 881 CI patients (plasma TM levels: n = 513; serum hs-CRP levels: n = 368) and 1067 healthy controls. The results of our meta-analysis suggested that plasma TM levels and serum hs-CRP levels in CI patients were significantly higher than those in healthy controls. In conclusion, increased plasma TM levels and serum hs-CRP levels in CI patients were associated with the development of CI in Asians.

Variants in the Atherogenic ALOX5AP, THBD, and KNG1 Genes Potentiate the Risk of Ischemic Stroke via a Genetic Main Effect and Epistatic Interactions in a Chinese Population

BACKGROUND

Ischemic stroke (IS) is a multifactorial disease that displays a strong genetic predisposition. However, the genetic architecture of IS has yet to be fully elucidated. It was hypothesized that epistasis between genes in multiple atherothrombotic pathways may play a vital role in determining the susceptibility to IS. The aim of the present study was to investigate the contributions of the hypothesized genetic factors to IS and the interactions between these genetic factors in a Chinese population.

METHODS

In this study, 351 cases with IS and 417 control subjects from a Chinese population were genotyped for single-nucleotide polymorphisms (SNPs) in 12 genes hypothesized to be involved in atherosclerosis, coagulation, and related pathways. We examined SNP main effects and epistatic interactions between these polymorphic loci.

RESULTS

rs710446 of the KNG1 gene was associated with IS susceptibility based on an additive genetic model (rs710446: P = .012; odds ratio [OR], 1.247; 95% confidence interval [CI], 1.050-1.481) after adjusting for covariates. Furthermore, an epistatic interaction between the ALOX5AP, THBD, and KNG1 gene was also identified in association with stroke susceptibility (P < .001 after 1000 permutations). Based on the chi-squared test, the OR of the high-risk combination of the three-locus model increased the risk of IS by 2.53-fold (95% CI, 1.60-4.01; P < .0001).

CONCLUSIONS

Our findings support the association of the epistatic interactions of ALOX5AP, THBD, and KNG1 and present novel evidence for the main effect of KNG1 gene on IS susceptibility, suggesting a modulation of stroke risk by a genetic main effect and gene-gene interactions.

Association of thrombomodulin Ala455Val dimorphism and inflammatory cytokines with carotid atherosclerosis in the Chinese Han population

Background and methods

It has been reported that C/T dimorphism at position 1418 of the thrombomodulin gene causes a cytosine (C) transition to thymidine (T), resulting in an alanine (A) to valine (V) substitution at amino acid position 455 (TM455). TM455 had been found not only in African American and American whites, but also in whites in The Netherlands and Sweden. Among these populations, the C/C genotype is predominant, although the distribution of this dimorphism is different. Thrombomodulin is an important anticoagulant protein that is downregulated in endothelial cells overlying atherosclerotic plaques and is also an anti-inflammatory molecule. TM455 is located in the last epidermal growth factor-like repeat of thrombomodulin, which is functionally important for protein C activation and thrombin binding. The distribution of thrombomodulin polymorphism and association between TM455, inflammatory cytokines, and carotid atherosclerosis in the Chinese Han population is unclear.

Methods

This thrombomodulin dimorphism was analyzed by allele-specific amplification in 144 patients with carotid atherosclerosis and in 384 healthy controls. TM455 was found in the Chinese Han population, but the genotype frequency and distribution of each genotype in this population differed substantially from that in other ethnic subgroups. The C/T and T/T genotypes were predominant in the Chinese Han population, and the frequency of the T allele in this population (63.8%) was much higher than that in whites in The Netherlands (18%), Sweden (26.1%), and the US (18.4%), and in blacks in the US (7.6%). The frequencies of these single nucleotide polymorphisms complied well with the Hardy-Weinberg equilibrium in healthy individuals. The C allele was significantly more common among patients with carotid atherosclerosis than in controls (P < 0.05). The frequency of the C allele was 45.5% in patients and 36.2% in controls. The thrombomodulin Ala455 genotypes C/C and C/T were significantly more common than the T/T genotype in patients with carotid atherosclerosis in the Chinese Han population. In addition, higher baseline levels of tumor necrosis factor alpha (55.45 ± 11.58 pg/mL versus 52.70 ± 10.74 pg/mL; P < 0.05), interleukin-6 (31.53 ± 10.51 pg/mL versus 27.73 ± 8.37 pg/mL; P < 0.01), and C-reactive protein (6.65 ± 2.01 mg/L versus 4.06 ± 1.03 mg/L; P < 0.01) were observed in patients with carotid atherosclerosis than in controls. Interestingly, compared with baseline inflammatory cytokine levels in those with the Val/Val genotype, higher baseline tumor necrosis factor alpha, interleukin-6, and C-reactive protein levels were observed for the Ala/Ala genotype in both patients with carotid atherosclerosis and healthy controls.

Conclusion

Our results support a significant association between thrombomodulin Ala455Val dimorphism, inflammatory cytokines, and carotid atherosclerosis in the Chinese Han population.

Thrombomodulin as a regulator of the anticoagulant pathway: implication in the development of thrombosis

Thrombomodulin is a cell surface-expressed glycoprotein that serves as a cofactor for thrombin-mediated activation of protein C (PC), an event further amplified by the endothelial cell PC receptor. The PC pathway is a major anticoagulant mechanism that downregulates thrombin formation and hedges thrombus formation. The objectives of this review were to review recent findings regarding thrombomodulin structure, its involvement in the regulation of hemostasis and further discuss the implication, if any, of the genetic polymorphisms in the thrombomodulin gene in the risk of development of thrombosis. We performed a literature search by using electronic bibliographic databases. Although the direct evaluation of risk situations associated with thrombomodulin mutations/polymorphisms could be of clinical significance, it appears that mutations that affect the function of thrombomodulin are rarely associated with venous thromboembolism. However, several polymorphisms are reported to be associated with increased risk for arterial thrombosis. Additionally studies on knock out mice as well studies on humans bearing rare mutations suggest that thrombomodulin dysfunction may be implicated in the pathogenesis of myocardial infraction.

Molecular biomarkers in stroke diagnosis and prognosis

Serum biomarkers related to the cascade of inflammatory, hemostatic, glial and neuronal perturbations have been identifed to diagnose and characterize intracerebral hemorrhage and cerebral ischemia. Interpretation of most markers is confounded by their latent rise, blood-brain barrier effects, the heterogeneity of etiologies and the wide range of normal values, limiting their application for early diagnosis, lesion size estimation and long-term outcome prediction. Certain hemostatic and inflammatory constituents have been found to predict response to thrombolysis and worsening due to infarct progression and secondary hemorrhage, offering a potential role for improved treatment selection and individualization of therapy. Biomarkers will become increasingly relevant for developing targets for neuroprotective therapies, monitoring response to treatment and as surrogate end points for treatment trials.