Three periods of one and a half decade of ischemic stroke susceptibility gene research: lessons we have learned

Posterior Circulation Stroke Secondary to Basilar Artery Thrombosis With a Fatal Outcome

Stroke is a regularly encountered emergency by emergency physicians, categorized based on the culprit artery and diagnosed based on non-contrast computerized tomography (CT) brain, which is supported by clinical examination that can be treated intravenously by thrombolytic agents or mechanical thrombectomy. Here we present one such case, which was brought to the emergency room with symptoms of posterior circulation stroke within 8 hours and underwent mechanical thrombectomy.

Scavenger Receptor Class B type 1 (SR-B1) and the modifiable risk factors of stroke

Stroke is a devastating disease that occurs when a blood vessel in the brain is either blocked or ruptured, consequently leading to deficits in neurological function. Stroke consistently ranked as one of the top causes of mortality, and with the mean age of incidence decreasing, there is renewed interest to seek novel therapeutic treatments. The Scavenger Receptor Class B type 1 (SR-B1) is a multifunctional protein found on the surface of a variety of cells. Research has found that that SR-B1 primarily functions in an anti-inflammatory and anti-atherosclerotic capacity. In this review, we discuss the characteristics of SR-B1 and focus on its potential correlation with the modifiable risk factors of stroke. SR-B1 likely has an impact on stroke through its interaction with smoking, diabetes mellitus, diet, physical inactivity, obesity, hypercholesterolemia, atherosclerosis, coronary heart disease, hypertension, and sickle cell disease, all of which are critical risk factors in the pathogenesis of stroke.

Influence of the Matrix Metalloproteinase 9 Geners3918242 Polymorphism on Development of Ischemic Stroke: A Meta-analysis

BACKGROUND

The association between matrix metalloproteinase 9 (MMP-9) gene -1562C/T (rs3918242) polymorphism and the susceptibility of ischemic stroke (IS) has been investigated. However, results were ambiguous and inconsistent. Therefore, we performed this study to better assess the potential relationship between rs3918242 polymorphism and susceptibility risk of IS.

METHODS

We included case-control studies concerning the relationship between the rs3918242 polymorphism and IS, and odds ratios with corresponding 95% confidence intervals were used to describe the associations. Furthermore, meta-regression analyses, heterogeneity, cumulative analyses, sensitivity analyses, and publication bias were examined.

RESULTS

A total of 19 studies were included for analysis. Significant associations with the risk of IS were detected for the rs3918242 polymorphism in overall population, Asians, and whites. When available data were stratified by gender, we found a significant correlation with the risk of IS in both males and females. Further subgroup analysis by the subtypes of IS showed that the rs3918242 polymorphism was significantly correlated with the risk of patients with large artery atherosclerosis. When stratified by age, we found that the rs3918242 polymorphism was significantly correlated with the risk of IS in patients both aged ≥65 years and >65 years. Both the diabetes and the nondiabetes subgroups reached significant results, and in an analysis stratified by smoking status, an increased risk of IS was associated with smoking.

CONCLUSIONS

The rs3918242 polymorphism may be a susceptible predictor of susceptibility of IS. Further large-scale studies are needed to verify the results of our findings.

Monogenic, Polygenic, and MicroRNA Markers for Ischemic Stroke

Ischemic stroke (IS) is a leading disease with high mortality and disability, as well as with limited therapeutic window. Biomarkers for earlier diagnosis of IS have long been pursued. Family and twin studies confirm that genetic variations play an important role in IS pathogenesis. Besides DNA mutations found previously by genetic linkage analysis for monogenic IS (Mendelian inheritance), recent studies using genome-wide associated study (GWAS) and microRNA expression profiling have resulted in a large number of DNA and microRNA biomarkers in polygenic IS (sporadic IS), especially in different IS subtypes and imaging phenotypes. The present review summarizes genetic markers discovered by clinical studies and discusses their pathogenic molecular mechanisms involved in developmental or regenerative anomalies of blood vessel walls, neuronal apoptosis, excitotoxic death, inflammation, neurogenesis, and angiogenesis. The possible impact of environment on genetics is addressed as well. We also include a perspective on further studies and clinical application of these IS biomarkers.

Association between CD14 rs2569190 C>T polymorphism and ischemic stroke susceptibility: a meta-analysis based on 5,277 subjects

INTRODUCTION

Previous epidemiological studies have suggested that CD14 rs2569190 C>T polymorphism plays an important role in ischemic stroke (IS) risk, but the results were inconsistent. Therefore, we conducted a meta-analysis to determine the association between CD14 rs2569190 C>T polymorphism and IS susceptibility.

METHODS

Online databases were searched from inception up to July 1, 2018, for studies concerning CD14 rs2569190 C>T polymorphism and its association with IS susceptibility. ORs and corresponding 95% CIs were calculated in the genetic models of each polymorphism locus with Stata Version 14.0. Furthermore, heterogeneity, meta-regression, accumulative analyses, sensitivity analyses, and publication bias were examined.

RESULTS

Overall, 10 observed studies involving 5,277 subjects were included in this meta-analysis on CD14 rs2569190 C>T polymorphism. Generally, no significant associations were found between CD14 rs2569190 C>T polymorphism and IS risk (allele contrast of T vs C: OR =1.03, 95% CI =0.96-1.12, P=0.41, I2=27.8%; co-dominant models of CT vs CC: OR =1.01, 95% CI =0.81-1.25, P=0.95, I2=51.9%; co-dominant models of TT vs CC: OR =1.04, 95% CI =0.89-1.22, P=0.62, I2=25.1%; dominant model of CT + TT vs CC: OR =1.02, 95% CI =0.84-1.25, P=0.82, I2=51.4%; recessive model of TT vs CC + CT: OR =1.07, 95% CI =0.95-1.22, P=0.28, I2=0%), similar to the results in the subgroup analysis.

CONCLUSION

The current evidence indicated that CD14 rs2569190 C>T polymorphism was not a critical risk factor for IS development.

Identification of genetic risk factors associated with ischaemic stroke in young Mexican patients

INTRODUCTION

Numerous polymorphisms in candidate genes coding for haemostatic system proteins have been proposed as risk factors for thrombosis.

METHODS

We performed a case-control study of consecutive ischaemic stroke survivors aged ≤ 45 years, treated at our neurology department from 2006 to 2014. Polymerase chain reaction-restriction fragment length polymorphism identified the following polymorphisms: Thr325Ile and Ala147Thr in TAFI, 4G/5G in PAI-1, PLA1/A2 in platelet glycoprotein IIb/IIIa, Glu298Asp in eNOS, and C677T in 5,10-MTHFR. A multivariate logistic regression analysis was performed to evaluate the independent risk of stroke.

RESULTS

204 cases and 204 age- and sex-matched controls were included in the study. Clinical and genetic variables associated with ischaemic stroke were hypertension (P=.03), tobacco use (P=.02), and the polymorphisms Glu298Asp (genotype: P=.001, allele frequency: P=.001) and C677T (genotype: P=.01); the Ala147Thr, Thr325IIe, 4G/5G, and PLA1/A2 mutations were not associated with ischaemic stroke. The 298Asp (P=.03) and T (P=.01) alleles, hypertension (P=.03), tobacco use (P=.01) and family history of stroke (P=.04) were identified as independent risk factors.

CONCLUSIONS

The polymorphisms Glu298Asp and C677T, affecting the eNOS and 5,10-MTHFR enzymes, respectively, and smoking, hypertension, and family history of stroke were associated with ischaemic stroke in young Mexican patients; this was not the case for the Thr325Ile, Ala147Thr, 4G/5G, and PLA1/A2 polymorphisms of the genes coding for fibrinolytic proteins and platelet receptors.

Manual versus Automated Rodent Behavioral Assessment: Comparing Efficacy and Ease of Bederson and Garcia Neurological Deficit Scores to an Open Field Video-Tracking System

Animal models of stroke have been crucial in advancing our understanding of the pathophysiology of cerebral ischemia. Currently, the standards for determining neurological deficit in rodents are the Bederson and Garcia scales, manual assessments scoring animals based on parameters ranked on a narrow scale of severity. Automated open field analysis of a live-video tracking system that analyzes animal behavior may provide a more sensitive test. Results obtained from the manual Bederson and Garcia scales did not show significant differences between pre- and post-stroke animals in a small cohort. When using the same cohort, however, post-stroke data obtained from automated open field analysis showed significant differences in several parameters. Furthermore, large cohort analysis also demonstrated increased sensitivity with automated open field analysis versus the Bederson and Garcia scales. These early data indicate use of automated open field analysis software may provide a more sensitive assessment when compared to traditional Bederson and Garcia scales.

Genetic risk factors for stroke in the genome-wide association era

IMPORTANCE OF THE FIELD

Recent genome-wide association studies (GWASs) have renewed interest in genetic determinants of a wide range of complex traits and disorders, including stroke.

AREAS COVERED IN THIS REVIEW

This paper reviews the current knowledge of genes that contribute to rare monogenic forms of stroke as well as more common 'garden variety' forms, focusing on the results of GWASs. Potential clinical pharmacogenetic and diagnostic applications of this information are considered. Publications from 1990 to September 2010 were identified through a Medline search using terms 'human stroke' and 'genetics', 'monogenic', 'familial', 'mutation', 'genome-wide association study', 'polymorphism', or 'genotype'.

WHAT THE READER WILL GAIN

The review synthesizes and collates the current understanding of genes that are involved across a range of stroke subphenotypes.

TAKE HOME MESSAGE

The complexity of stroke will make translation of genetic findings into new diagnostic or therapeutic tools relatively more challenging than for some other conditions and tempers the authors' enthusiasm for the eventual clinical utility of this information.