Genetic Associations of Angiotensin-Converting Enzyme with Primary Intracerebral Hemorrhage: A Meta-analysis

Intracerebral Hemorrhage Genetics

Intracerebral hemorrhage (ICH) is a devastating type of stroke, frequently resulting in unfavorable functional outcomes. Up to 15% of stroke patients experience ICH and approximately half of those have a lethal outcome within a year. Considering the huge burden of ICH, timely prevention and optimized treatment strategies are particularly relevant. Nevertheless, ICH management options are quite limited, despite thorough research. More and more trials highlight the importance of the genetic component in the pathogenesis of ICH. Apart from distinct monogenic disorders of familial character, mostly occurring in younger subjects, there are numerous polygenic risk factors, such as hypertension, neurovascular inflammation, disorders of lipid metabolism and coagulation cascade, and small vessel disease. In this paper we describe gene-related ICH types and underlying mechanisms. We also briefly discuss the emerging treatment options and possible clinical relevance of the genetic findings in ICH management. Although existing data seems of more theoretical and scientific value so far, a growing body of evidence, combined with rapidly evolving experimental research, will probably serve clinicians in the future.

Association between Angiotensin Converting Enzyme Insertion/Deletion gene polymorphism with the risk of Hemorrhagic Stroke: A systematic review and Meta-Analysis of 53 studies

BACKGROUND AND AIMS

Hemorrhagic stroke (HS) results in significant mortality and disability worldwide. Angiotensin Converting Enzyme (ACE) is responsible for blood pressure regulation and vascular homeostasis. Our objective was to conduct a comprehensive meta-analysis for ascertaining the association of ACE I/D polymorphism with HS since a number of studies depicted inconclusive evidence.

METHODS

Literature search was performed till July 10, 2020 in PubMed, EMBASE, Cochrane, Chinese National Knowledge Information and Google Scholar databases with keywords: ('Angiotensin Converting Enzyme' OR 'ACE') AND ('Single Nucleotide polymorphisms' OR 'SNP') AND ('Hemorrhagic stroke or 'HS'). Pooled Odds Ratio (OR) and 95% Confidence Interval (CI) were determined for gene-disease association using either fixed (when I² < 50%) or random effect (when I² > 50%) models. Risk of bias in studies was assessed using funnel plots and sensitivity analyses. Statistical analysis was performed using STATA version 13.0 software.

RESULTS

A total of 53 studies having 5186 HS and 7347 healthy control subjects were included in our meta-analysis. Pooled analyses showed that ACE I/D gene polymorphism had significant association with risk of HS in overall study population [(dominant model: OR = 1.29, 95% CI = 1.12-1.50 & recessive model: OR = 1.79, 95% CI = 1.46-2.20)]. Population subgroup analyses further revealed significant relationship of ACE I/D polymorphism with ICH in Asians (recessive: OR 1.97, 95% CI = 1.57-2.47) but not in Caucasians (recessive: OR 1.02, 95% CI = 0.76-1.36).

CONCLUSION

This meta-analysis suggests that ACE I/D polymorphism may lead to risk of HS and can be a potential biomarker for HS susceptibility especially in Asian population.

Genetic risk of Spontaneous intracerebral hemorrhage: Systematic review and future directions

BACKGROUND

Although highly heritable, few genes have been linked to spontaneous intracerebral hemorrhage (SICH), which does not currently have any evidence-based disease-modifying therapy. Individuals of African ancestry are especially susceptible to SICH, even more so for indigenous Africans. We systematically reviewed the genetic variants associated with SICH and examined opportunities for rapidly advancing SICH genomic research for precision medicine.

METHOD

We searched the National Human Genome Research Institute-European Bioinformatics Institute (NHGRI-EBI) Genome Wide Association Study (GWAS) catalog and PubMed for original research articles on genetic variants associated with SICH as of 15 June 2019 using the PRISMA guideline.

RESULTS

Eight hundred and sixty-four articles were identified using pre-specified search criteria, of which 64 met the study inclusion criteria. Among eligible articles, only 9 utilized GWAS approach while the rest were candidate gene studies. Thirty-eight genetic loci were found to be variously associated with the risk of SICH, hematoma volume, functional outcome and mortality, out of which 8 were from GWAS including APOE, CR1, KCNK17, 1q22, CETP, STYK1, COL4A2 and 17p12. None of the studies included indigenous Africans.

CONCLUSION

Given this limited information on the genetic contributors to SICH, more genomic studies are needed to provide additional insights into the pathophysiology of SICH, and develop targeted preventive and therapeutic strategies. This call for additional investigation of the pathogenesis of SICH is likely to yield more discoveries in the unexplored indigenous African populations which also have a greater predilection.

Genetic Polymorphisms Associated with Spontaneous Intracerebral Hemorrhage

Differences in the incidence of spontaneous intracerebral hemorrhage (ICH) between ethnicities exist, with an estimated 42% of the variance explained by ethnicity itself. Caucasians have a higher proportion of lobar ICH (LICH, 15.4% of all ICH) than do Asians (3.4%). Alterations in the causal factor exposure between countries justify part of the ethnic variance in ICH incidence. One third of ICH risk can be explained by genetic variation; therefore, genetic differences between populations can partly explain the difference in ICH incidence. In this paper, we review the current knowledge of genetic variants associated with ICH in multiple ethnicities. Candidate gene variants reportedly associated with ICH were involved in the potential pathways of hypertension, vessel wall integrity, lipid metabolism, endothelial dysfunction, inflammation, platelet function, and coagulopathy. Furthermore, variations in APOE (in multiple ethnicities), PMF1/SLC25A44 (in European), ACE (in Asian), MTHFR (in multiple ethnicities), TRHDE (in European), and COL4A2 (in European) were the most convincingly associated with ICH. The majority of the associated genes provide small contributions to ICH risk, with few of them being replicated in multiple ethnicities.

Genetic risk factors for spontaneous intracerebral haemorrhage

Intracerebral haemorrhage (ICH) is associated with the greatest morbidity and mortality of all stroke subtypes. Established risk factors for ICH include hypertension, alcohol use, current cigarette smoking, and use of oral anticoagulants and/or antiplatelet agents. Familial aggregation of ICH has been observed, and the heritability of ICH risk has been estimated at 44%. Few genes have been found to be associated with ICH at the population level, and much of the evidence for genetic risk factors for ICH comes from single studies conducted in relatively small and homogenous populations. In this Review, we summarize the current knowledge of genetic variants associated with primary spontaneous ICH. Two variants of the gene encoding apolipoprotein E (APOE) - which also contributes to the pathogenesis of cerebral amyloid angiopathy - are the most likely candidates for variants that increase the risk of ICH. Other promising candidates for risk alleles in ICH include variants of the genes ACE, PMF1/SLC25A44, COL4A2, and MTHFR. Other genetic variants, related to haemostasis, lipid metabolism, inflammation, and the CNS microenvironment, have been linked to ICH in single candidate gene studies. Although evidence for genetic contributions to the risk of ICH exists, we do not yet fully understand how and to what extent this information can be utilized to prevent and treat ICH.

Polymorphisms in the Promoters of the MMP-2 and TIMP-2 Genes Are Associated with Spontaneous Deep Intracerebral Hemorrhage in the Taiwan Population

Background

Spontaneous intracerebral hemorrhage (ICH) is a devastating stroke subtype. Matrix metalloproteinases (MMPs) function in the degradation of extracellular matrix and the activities of MMPs are modulated by their endogenous inhibitors, tissue inhibitors of metalloproteinases (TIMPs). This study aimed to discuss relationship of MMP-2 and TIMP-2 to spontaneous deep ICH (SDICH) susceptibility and hematoma size.

Methods

Associations were tested by logistic regression and general linear models (GLM) where appropriate, adjusting with covariables of age, sex, hypertension, diabetes mellitus, smoking, and alcohol consumption. Association analyses were performed first by stratification of genders and then by the age of 65 years old (y/o). Elder population was defined as subjects who were older than 65 y/o.

Results

There were 396 SDICH patients and 376 control subjects in this study. In the elder group, rs7503607 C>A variant in TIMP-2 was associated with SDICH in male and overall patients (OR = 3.49, 95% CI 1.45 to 8.40, P = 0.005 and OR = 2.45, 95% CI 1.37 to 4.38, P = 0.003, respectively) in additive genetic model. In recessive genetic model, rs2285053 TT genotype in MMP-2 was correlated to SDICH in male patients and overall elder group (OR = 7.30, 95% CI 1.3 to 40, P = 0.02 and OR = 2.91, 95% CI 1.02 to 8.31, P = 0.046, respectively), and rs7503726 AA genotype in TIMP-2 was associated with SDICH in female patients (OR = 0.29, 95% CI 0.1 to 0.84, P = 0.02). In younger male and overall younger patients, SDICH patients who had supratentorial hemorrhage had significantly lower frequency of AA genotypes in rs7503726 than those with infratentorial hemorrhage (OR = 0.36, 95% CI 0.17 to 0.75, P = 0.006 and OR = 0.43, 95% CI 0.22 to 0.84, P = 0.014, respectively). Hemorrhage size increased by 9.7 (95% CI 2.1 to 43, P = 0.004) cm³ per minor allele (A) of the rs7503607 variant in the elder female patients and increased by 4.3 (95% CI 1.4 to 12.9, P = 0.009) cm³ per minor allele (A) in all elder patients. In younger patients, the hemorrhage size decreased by 3.3 (95% CI 1.2 to 9.5, P = 0.03) cm³ per minor allele of the s7503726 variant in the female patients.

Conclusions

This study showed a significant association between the variants of MMP-2 and TIMP-2 promoters and SDICH susceptibility with significant age and gender differences. Hemorrhage location and size might be affected by TIMP-2 promoter variants in the SDICH patients.

Association between angiotensin converting enzyme gene insertion/deletion polymorphism and intracerebral haemorrhage in North Indian population: a case control study and meta-analysis

The purpose of this study was to determine the relationship between Angiotensin converting enzyme (ACE) insertion/deletion polymorphism and ICH with an ACE level in a North Indian population. Patient with ICH and age- and sex- matched control subjects were recruited. Case control study design was used. Genotyping was performed by using Polymerase chain reaction. Serum ACE levels were measured by colorimetric method. Our results were integrated with other reported studies across different countries in a meta-analysis. One hundred and six patients with ICH and 106 age- and sex- matched control subjects were recruited. Mean age of cases and control subjects were 53.4 ± 1 and 52.9 ± 13.4, respectively. The DD genotypes were more frequency distributed in cases compared with controls (OR 2; 95 % CI, 1.02-3.8, P = 0.04) under a recessive model of inheritance. Meta-analysis suggests significant association between ACE I/D polymorphism and risk of ICH (OR 1.98; 95 % CI, 1.53-2.57) under the recessive model of inheritance and under the dominant model of inheritance (OR 1.31; 95 % CI, 1.18-1.45). The findings of the present study show a significant association between ACE insertion/deletion polymorphism and ICH. Meta-analysis indicate that ACE I/D polymorphism may be a susceptible marker for risk factor of ICH in Asian population.