Evaluation of the angiotensin-converting enzyme insertion/deletion polymorphism and the risk of ischaemic stroke

Angiotensin-converting enzyme gene insertion/deletion polymorphism and risk of ischemic stroke complication among patients with hypertension in the Ethiopian population

Background

Ischemic stroke is a complicated, multifaceted condition brought on by a confluence of vascular, environmental, and genetic variables. The burden of ischemic stroke is currently rising in terms of death, morbidity, and disability worldwide. Genetic variables also play significant roles in the pathophysiology of hypertension and ischemic stroke in addition to the greatest effects of demographic, clinical, and behavioral risk factors. The key functional variation of the ACE gene that has drawn the most interest is the ACE I/D variant. Even though the ACE gene I/D polymorphism has been widely studied, the findings of investigations on the involvement of this polymorphism in ischemic stroke were contradictory and provide conflicting data. The goal of this study was to look into the effect of the ACE gene I/D polymorphism on the risk of ischemic stroke in patients with hypertension.

Methods

A hospital-based case-control study was carried out in 36 cases of patients with hypertensive IS and 36 age- and sex-matched healthy controls. Clinical and biochemical parameters were measured to assess the associated risk factors. The DNA was isolated from blood samples, and the ACE I/D genotypes were identified using polymerase chain reaction and analyzed by agarose gel electrophoresis.

Results

The ACE-DD genotype (OR = 3.71, 95% CI = 1.02-13.5; P < 0.05) and D allele (OR = 2.07, 95% CI = 1.06-4.03; P < 0.05) were significantly more common in patients than in controls, indicating that it is a risk factor for the development of ischemic stroke in hypertensive individuals.

Conclusion

There is a significant correlation between the ACE gene I/D polymorphism and the development of ischemic stroke in patients with a history of hypertension in the Ethiopian population.

Association of laboratory parameters and genetic polymorphisms with ischemic stroke in Chinese Han population

Numerous genetic polymorphisms and clinical laboratory parameters are associated with ischemic stroke (IS). However, the results of such studies have frequently been inconsistent. The aim of the present study was to evaluate associations between clinical laboratory parameters with genetic polymorphisms that influence the risk of IS in a Chinese Han population. Clinical laboratory parameters were measured by an automatic biochemical analyzer. Genotype and allele frequencies of the polymorphisms angiotensin-converting enzyme (ACE) D/I, methylene tetrahydrofolate reductase (MTHFR) C677T and β-fibrinogen (β-Fg) A/G, 455/148T/C were characterized by restriction fragment length polymorphism-PCR. Furthermore, the gene polymorphisms plasminogen activator inhibitor (PAI)-1-4G/5G and apolipoprotein E (ApoE) ε2,3,4 were characterized by allele-specific PCR. The associations of genotype and allele frequencies of the six risk genes in different groups with clinical laboratory parameters were analyzed by chi-square tests. The distribution maps of the polymorphisms of the six genes and clinical laboratory parameters were compared between a control group of 336 healthy individuals and 762 patients with IS. Certain laboratory parameters were associated with ACE I/D, β-Fg-455 A/G and PAI-1 4G/5G. The D allele of ACE I/D was associated with high levels of total cholesterol and low-density lipoprotein cholesterol (LDL-C). Furthermore, high levels of fasting blood glucose, triglyceride and LDL-C were risk factors for IS. There were significant differences in the genotype frequencies of ACE I/D, β-Fg-455 A/G and β-Fg-148 T/C between the IS and the control group. In conclusion, clinical laboratory parameters were associated with the risk of polymorphisms of IS-related genes. The present results support the determination of a range of control values of clinical laboratory parameters for common genotypes in patients with diabetes and hyperlipidemia as a strategy for the early prevention of IS.

Association Between the Angiotensin-Converting Enzyme I/D Polymorphism and Risk of Cerebral Small Vessel Disease: A Meta-Analysis Based on 7186 Subjects

INTRODUCTION

Cerebral small vessel disease (CSVD) causes a quarter of all strokes and is the most common pathology underlying vascular dementia. However, the mechanism of CSVD remains unclear. Numerous studies have investigated whether the angiotensin-converting enzyme (ACE) intersection/deletion (I/D) polymorphism influences the risk of CSVD, but the results are controversial.

METHODS

We searched English and Chinese databases and calculated the odds ratio (OR) and 95% confidence interval (CI) to examine the existence of genetic associations between the ACE I/D polymorphism and the risk of CSVD. All relevant studies were screened and meta-analyzed using Review Manager 5.4.

RESULTS

A total of 27 studies involving 7,186 subjects were identified for the meta-analysis. The results of five genetic models showed a significantly increased risk of CSVD (allelic, OR=1.30; recessive, OR=1.41; dominant, OR=1.34; homozygous, OR=1.55 and heterozygous OR=1.22) in the overall analysis. Furthermore, in subgroup analysis, increased CSVD risks were also observed in Asian and Caucasian populations. We also found no relationship between ACE I/D and leukoaraiosis (LA) in patients with lacunar infarction (LI).

CONCLUSION

The ACE I/D polymorphism was positively associated with CSVD in both populations. However, this polymorphism did not increase the risk of LA in LI patients.

ACE-Triggered Hypertension Incites Stroke: Genetic, Molecular, and Therapeutic Aspects

Stroke is the second largest cause of death worldwide. Angiotensin converting enzyme (ACE) gene has emerged as an important player in the pathogenesis of hypertension and consequently stroke. It encodes ACE enzyme that converts the inactive decapeptide angiotensin I to active octapeptide, angiotensin II (Ang II). Dysregulation in the expression of ACE gene, on account of genetic variants or regulation by miRNAs, alters the levels of ACE in the circulation. Variable expression of ACE affects the levels of Ang II. Ang II acts through different signal transduction pathways via various tyrosine kinases (receptor/non-receptor) and protein serine/threonine kinases, initiating a downstream cascade of molecular events. In turn these activated molecular pathways might lead to hypertension and inflammation thereby resulting in cardiovascular and cerebrovascular diseases including stroke. In order to regulate the overexpression of ACE, many ACE inhibitors and blockers have been developed, some of which are still under clinical trials.

Gene polymorphisms of angiotensin-converting enzyme and angiotensinogen and risk of idiopathic ischemic stroke

OBJECTIVE

The renin-angiotensin system (RAS) is a hormonal signaling mechanism implicated in the atherosclerosis and regulation of blood pressure. Angiotensin-converting enzyme (ACE) a key enzyme in the RAS, plays important roles in vascular remodeling atherosclerosis, and ischemic stroke. The aim of this study was to examine the possible contribution of the I/D in the ACE gene, M235T and T174M in the angiotensinogen (AGT) gene polymorphisms with ischemic stroke in young Mexican population.

MATERIALS AND METHODS

A total of 224 patients with diagnosis of idiopathic ischemic stroke ≤45 years of age, and 224 controls matched by age and gender, were recruited from 2006 and 2016. The I/D, M235T and T174M polymorphisms were determined in all participants by PCR-RFLP.

RESULTS

There was a significant difference in the M235T genotype distribution (p = 0.01) and allele frequency between two groups (p = 0.01). Also, we found a significant difference in the T174M genotype distribution (p = 0.01) and the allele frequency between groups; (p = 0.02). In contrast, in I/D polymorphism, there was a similar genotype distribution; (p = 0.20) and allele distribution (p = 0.20). There were independent factors for ischemic stroke: M235T and T174M polymorphisms, smoking, hypertension, and familial history of atherothrombotic disease. The AGT levels were increased in the group of patients with stroke compared with the control group, but the AGT levels were not influenced by the allele or genotype in each polymorphism.

CONCLUSIONS

The M235T and T174M polymorphisms represented an increased risk for stroke in young Mexican individuals. In contrast, the I/D was not associated with in the same group of patients. The AGT levels were higher in the acute phase of stroke, but it was not determined by the polymorphisms.

Angiotensin converting enzyme (I/D) gene polymorphism contributes to ischemic stroke risk in Caucasian individuals: a meta-analysis based on 22 case-control studies

BACKGROUND

Stroke is a multifactorial disease in which genetic factors play an important role. Previous studies associated angiotensin converting enzyme (ACE) (insertion/deletion, I/D) gene polymorphism with ischemic stroke risk in Caucasian individuals reported conflicting results. The purpose of this study was to evaluate the association between ACE (I/D) gene polymorphism and ischemic stroke risk by a meta-analysis.

METHODS

The related studies were searched in MEDLINE, EMBASE and HuGEnet databases. The odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for ischemic stroke risk associated with this polymorphism were estimated using fixed-effect or random-effects model. Twenty-two studies (5528/5081 cases/controls) were eligible in our meta-analysis.

RESULTS

Overall, statistical associations of the ACE (I/D) polymorphism with ischemic stroke risk were found in dominant model (DD + ID versus II) : OR = 1.21, 95% CI = (1.06,1.38), P = 0.006, recessive model (DD versus ID + II): OR = 1.28, 95% CI = (1.05,1.55), P = 0.01, and homozygote comparison (DD versus II): OR = 1.37, 95% CI = (1.14,1.65), P = 0.001 for Caucasians. When stratifying according to stroke subtypes, there were similarly significant differences for small vessel disease in dominant model (DD + ID versus II) : OR = 1.44, 95% CI = (1.01,2.05), P = 0.04, recessive model (DD versus ID + II): OR = 1.30,95% CI = (1.09,1.55), P = 0.004, and homozygote comparison (DD versus II): OR = 1.44, 95% CI = (1.15,1.80), P = 0.001.

CONCLUSION

This analysis suggests that the ACE (I/D) polymorphism may be a risk factor for ischemic stroke, genotype DD of ACE could increase the risk of ischemic stroke in Caucasians. Subgroup analyses indicate that stroke subtypes may be a genetic risk factor of ischemic stroke, and there might be a greater genetic liability with small vessel disease.

Genetics of ischaemic stroke in young adults

Background

Stroke may be a clinical expression of several inherited disorders in humans. Recognition of the underlined genetic disorders causing stroke is important for a correct diagnosis, for genetic counselling and, even if rarely, for a correct therapeutic management. Moreover, the genetics of complex diseases such the stroke, in which multiple genes interact with environmental risk factors to increase risk, has been revolutionized by the Genome-Wide Association Study (GWAS) approach.

Scope of review

Here we review the single-gene causes of ischemic stroke, bringing the reader from the candidate gene method toward the exciting new horizons of genetic technology.

Major conclusions

The aetiological diagnosis of ischemic stroke in young adults is more complex than in the elderly. The identification of a genetic cause is important to provide appropriate counseling and to start a correct therapy, when available. The advent of GWAS technology, such as for other complex pathological conditions, has contributed enormously to the understanding of many of these genetic bases. For success large, well phenotyped case cohorts are required, and international collaborations are essential.

General significance

This review focuses on the main causes of genetically-based ischemic stroke in young adults, often classified as indeterminate, investigating also the recent findings of the GWAS, in order to improve diagnostic and therapeutic management.

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The aetiological diagnosis of stroke in young adults needs a different and more complex diagnostic work up than in older adults.

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Stroke may be a clinical expression of several inherited disorders in humans.

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The most common genetic causes of stroke are CADASIL, Fabry and mitochondrial diseases.

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Recognition of the underlined genetic disorders causing stroke is important for the correct management of the patient.

ACE-II genotype and I allele predicts ischemic stroke among males in south India

Two hundred ischemic stroke patients and 193 age and sex matched healthy controls were studied for the presence of Angiotensin Converting Enzyme Insertion/Deletion (ACE I/D) gene polymorphism. The PCR studies revealed that ACE 'II' (OR = 2.055; p = 0.004) genotype and 'I' (OR = 1.411; p = 0.018) alleles were significantly associated with IS patients. Gender specific analysis revealed a strong association of 'II' (OR = 2.044; p = 0.014) genotype and 'I' (OR = 1.531; p = 0.011) allele with male sex. Classification of patients based on TOAST criteria, revealed a significant association for 'II' genotype (OR = 1.713; p = 0.043) and 'I' (OR = 1.382; p = 0.039) allele in LVD patients only. When the data was stratified based on age and sex, a statistically significant association was observed for ACE 'II' genotype (OR = 2.288; p = 0.006) and 'I' allele (OR = 1.395; p = 0.054) in IS male patients of > 50 years of age. The ACE 'D' allele was found to be increased in controls (OR = 0.709; p = 0.018) than IS patients. Multivariate logistic regression analysis showed that smoking and diabetes were the most powerful independent risk factor in LVD type of stroke. Thus, we presented here an evidence for a strong association of ACE 'II' genotype and 'I' allele compounded by factors such as smoking and diabetes among south Indian IS patients.

Association between the ACE I/D polymorphism and risk of ischemic stroke: an updated meta-analysis of 47,026 subjects from 105 case-control studies

BACKGROUND

The association between the angiotensin-converting enzyme insertion/deletion (ACE I/D) polymorphism and risk of ischemic stroke (IS) remains controversial and ambiguous. To clarify this association, a large meta-analysis was performed.

METHODS

Electronic databases in both English and Chinese were used to identify relevant studies (updated in February 2014). Odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to describe the strength of the association.

RESULTS

One hundred and fifty eligible studies, including 18,258 IS cases and 28,768 controls, were identified. Meta-analysis of these studies pointed to a significant association between the ACE I/D polymorphism and IS risk: (D vs. I: OR=1.354, 95% CI=1.272-1.440, P<0.001; DD vs. II: OR=1.755, 95% CI=1.561-1.973, P<0.001; ID vs. II: OR=1.178, 95% CI=1.098-1.263, P<0.001; DD vs.

ID/II

OR=1.535, 95% CI=1.399-1.684, P<0.001; DD/ID vs. II: OR=1.353, 95% CI=1.251-1.463, P<0.001). Subgroup analysis revealed a significantly elevated risk among Asians, but with borderline statistical significance among Caucasians.

CONCLUSION

This meta-analysis indicated that the ACE I/D polymorphism may be a genetic susceptibility factor for IS, especially among Asians, but with borderline statistical significance for Caucasians. Further investigations are needed to validate our conclusions.

Angiotensin-converting enzyme gene insertion/deletion polymorphism and small vessel cerebral stroke in Indian population

Background. Hypertension is an established risk factor for small-vessel cerebral stroke and the renin-angiotensin system plays an important role in the maintenance of blood pressure. We aimed at evaluating the contribution of the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism to the risk of small-vessel stroke in south Indian population. Materials and Methods. We investigated 128 patients diagnosed with small-vessel stroke and 236 age, and gender-matched healthy controls. ACE I/D polymorphism was detected by polymerase chain reaction. Results. Hypertension was significantly more prevalent in the patient group and was associated with 6-fold increase in risk for stroke. ACE genotypes were in Hardy-Weinberg equilibrium in both patients and controls. Prevalence of DD, ID, and II genotypes in cases (34.4%, 43.7%, and 28%) did not differ significantly from controls (31.8%, 43.2%, and 25%). The polymorphism was not associated with small-vessel stroke (OR: 1.34; 95% CI: 0.52–1.55). However, diastolic blood pressure was associated with the ACE I/D genotypes in the patients. (DD; 90.2 ± 14.2> ID; 86.2 ± 11.9> II; 82.3 ± 7.8 mm Hg,  P = 0.047). Conclusion. Our study showed that hypertension, but not ACE I/D polymorphism, increased the risk of small-vessel stroke.

Angiotensin-converting enzyme insertion/deletion polymorphism contributes to ischemic stroke risk: a meta-analysis of 50 case-control studies

Background

Many studies have investigated the association between the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and risk of ischemic stroke. However, the evidence is inadequate to draw robust conclusions because most studies were generally small and conducted in heterogeneous populations. To shed light on these inconclusive findings, we conducted a large meta-analysis of studies relating the ACE I/D polymorphism to the risk of ischemic stroke.

Methods

Relevant studies were identified by searching PubMed and Embase through February 2012 and by reviewing the references of retrieved articles. We included studies that reported odds ratio (OR) with 95% confidence interval (CI) for the association between this polymorphism and ischemic stroke risk.

Results

Fifty independent publications, with 10 070 stroke cases and 22 103 controls, were included. The results indicated that the DD homozygote carriers had a 37% higher risk of ischemic stroke when compared with the homozygotes II and heterozygote ID [odds ratio (OR) = 1.37, 95% confidence interval (CI): 1.22–1.53]. Subgroup analyses indicated that this higher risk was more pronounced among Asians, hospital-based studies, and small vessel disease (SVD). Potential publication bias may exist, but correction for this bias using a formal statistical method did not materially alter the combined risk estimate.

Conclusion

The results of our meta-analysis indicate that the D allele of ACE I/D polymorphism is a low-penetrance susceptibility marker of ischemic stroke.

Genetics of stroke

Stroke is the second most common cause of death and the most common cause of disability in developed countries. Stroke is a multi-factorial disease caused by a combination of environmental and genetic factors. Numerous epidemiologic studies have documented a significant genetic component in the occurrence of strokes. Genes encoding products involved in lipid metabolism, thrombosis, and inflammation are believed to be potential genetic factors for stroke. Although a large group of candidate genes have been studied, most of the epidemiological results are conflicting. Studies of stroke as a monogenic disease have made huge progress, and animal models serve as an indispensable tool to dissect the complex genetics of stroke. In the present review, we provide insight into the role of in vivo stroke models for the study of stroke genetics.

Angiotensin-converting enzyme insertion/deletion polymorphism has no effect on the risk of atherosclerotic stroke or hypertension

BACKGROUND AND PURPOSE

Stroke is a heterogeneous multifactorial disease. Hence, a large number of candidate genes are involved in stroke pathophysiology, such as blood pressure regulation and atherosclerosis. Although angiotensin-converting enzyme insertion/deletion (ACE I/D) polymorphism is considered to have a role in hypertension, coronary artery disease, and myocardial infarction, its relationship with cerebrovascular disease and hypertension in stroke in different ethnic populations is still inconsistent.

METHODS

ACE I/D polymorphism, detected by polymerase chain reaction (PCR), was studied in 97 patients with large-vessel and 60 patients with small-vessel atherosclerotic stroke (44 asymptomatic, 16 symptomatic lacunes) and 85 healthy subjects with normal brain imaging. The demographic data, lipid profile and risk factors of patients and controls were obtained retrospectively.

RESULTS

ACE genotypes were in Hardy-Weinberg equilibrium in both patients and controls. Prevalences of DD, ID and II genotype were 41%, 40%, and 19%, respectively, in the stroke group. Differences in ACE I/D polymorphism distribution were statistically insignificant between the groups. This lack of association between stroke and ACE I/D polymorphism did not change in the presence of traditional risk factors (hypertension, diabetes mellitus, smoking, and dyslipidemia). Although hypertension was significantly more common in the patient groups, ACE I/D polymorphism showed no effect on hypertension risk. This lack of association also did not change according to groups or in the presence of diabetes mellitus, male gender or smoking.

CONCLUSION

ACE I/D polymorphism did not predict the risk of stroke or hypertension in our population living in the western Black Sea region of Turkey.

Genetic risk factors for arterial ischemic stroke in children: a possible MTHFR and eNOS gene-gene interplay?

In order to investigate the influence of genetic factors in childhood stroke, we compared the distributions of mutations/ polymorphisms affecting hemostasis and/or endothelial function (factor V [FV] Leiden, factor II [FII] G20210A, methylenetetrahydrofolate reductase [MTHFR] C677T, angiotensin-converting enzyme [ACE] insertion/deletion [ID], and endothelial nitric oxide synthase [eNOS] G894T) among children with stroke and controls. A total number of 26 children with arterial ischemic stroke and a control group of 50 healthy children were included in the study. No statistically significant differences in allelic and genotypic distribution were detected in comparisons between groups. However, when combined genotypes were analyzed, statistical significance was observed for the association of MTHFR CT and eNOS TT gene variants. The results of our study suggest that this genotype combination represents a risk factor of 7.2 (P = .017) for arterial ischemic stroke in children.

Prevalence of the angiotensin I converting enzyme gene insertion/deletion polymorphism in a healthy Turkish population

Angiotensin converting enzyme (ACE) plays an essential role in the renin-angiotensin system. It converts angiotensin I to angiotensin II and inactivates bradykinin and tachykinins. Numerous studies have been published investigating associations of the ACE gene I/D polymorphism with various pathophysiological conditions. We examined the prevalence of the ACE I/D polymorphism in a sample of healthy volunteers from western Turkey, including 1063 healthy Turkish controls. Analysis of the ACE I/D gene polymorphisms by polymerase chain reaction found frequencies of 16.1% for the II genotype, 47.7% for the ID genotype, and 36.2% for the DD genotype. The allele frequency was 39.9% for the I alleles and 60.1% for the D allele. This study demonstrates that the allele and genotype frequency values for the Turkish population are similar to previously published frequencies for Caucasian populations.

Angiotensin-converting enzyme (ACE), angiotensinogen (AGT), and angiotensin II type 1 receptor (AT1R) gene polymorphisms in generalized aggressive periodontitis

AIM

Host response to periodontopathic microorganisms can be modulated by genetic factors. Accumulated evidence highlighted the role of renin-angiotensin system (RAS) in inflammatory response thus potential implication of this molecular system in the pathogenesis of periodontitis can be suggested. The present study investigated common genetic variants of molecules within the RAS family namely angiotensin-converting enzyme (ACE), angiotensinogen (AGT) and angiotensin II type 1 receptor (AT1R) in relation to generalized aggressive periodontitis (G-AgP).

METHODS

DNA was obtained from peripheral blood of 103 G-AgP patients and 100 periodontally healthy subjects. ACE I/D, AGT M235T and AT1R A1166C polymorphisms were genotyped by polymerase chain reaction and restriction fragment length polymorphism method. Chi-square, ANOVA and logistic regression were used in statistical analyses.

RESULTS

Both ACE I/D and AT1R polymorphisms were similar in G-AgP and healthy groups (p>0.05). G-AgP subjects exhibited decreased AGT TT genotype and T allele frequency as compared to healthy subjects (p<0.05). The same trend was also observed in the nonsmoker subgroup regarding investigated RAS polymorphisms.

CONCLUSIONS

Present findings suggest that AGT M235T TT genotype and T allele might be associated with decreased risk for G-AgP in Turkish population.

Genetics of ischaemic stroke

Ischaemic stroke is a heterogeneous multifactorial disorder. Epidemiological data provide substantial evidence for a genetic component to the disease, but the extent of predisposition is unknown. Large progress has been made in single-gene disorders associated with ischaemic stroke. The identification of NOTCH3 mutations in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) has led to new insights on lacunar stroke and small-vessel disease. Studies of sickle-cell disease have drawn attention to the importance of modifier genes and of gene-gene interactions in determining stroke risk. They have further highlighted a potential role of genetics in predicting stroke risk. Little is known about the genes associated with complex multifactorial stroke. There are probably many alleles with small effect sizes. Genetic-association studies on a wide range of candidate pathways, such as the haemostatic and inflammatory system, homocysteine metabolism, and the renin-angiotensin aldosterone system, suggest a weak but significant effect for several at-risk alleles. Genome-wide linkage studies in extended pedigrees from Iceland led to the identification of PDE4D and ALOX5AP. Specific haplotypes in these genes have been shown to confer risk for ischaemic stroke in the Icelandic population, but their role in other populations is unclear. Advances in high-throughput genotyping and biostatistics have enabled new study designs, including genome-wide association studies. Their application to ischaemic stroke requires the collaborative efforts of multiple centres. This approach will contribute to the identification of additional genes, novel pathways, and eventually novel therapeutic approaches to ischaemic stroke.

Genetic polymorphisms for the study of multifactorial stroke

Single-gene disorders explain only a minority of stroke cases. Stroke represents a complex trait, which is usually assumed to be polygenic. On this topic, the role of a wide number of candidate genes has been investigated in stroke through association studies, with controversial results. Therefore, it is difficult for the clinician to establish the validity and the level of clinical applicability of the previously reported associations between genetic factors and stroke. This review is an update and an extensive analysis of the more recent association studies conducted in stroke. We evaluated a number of studies on several candidate genes (including F5, F2, FGA/FGB/FGG, F7, F13A1, vWF, F12, SERPINE1, ITGB3/PLA1/PLA2/ITGA2B, ITGA2, GP1BA, ACE, AGT, NOS3, APOE, LPL, PON1, PDE4D, ALOX5AP, MTHFR, MTR, and CBS), providing a final panel of genes and molecular variants. We categorized this panel in relation to the degree of association with stroke, supported by the results of meta-analyses and case-control studies. Our findings could represent a useful tool to address further molecular investigations and to realize more detailed meta-analyses.

Angiotensin-converting enzyme insertion/deletion polymorphism and the risk of ischemic stroke in a South Indian population

Stroke is one of the most complex diseases with several subtypes, arising from numerous gene-gene and gene-environmental interactions. The aim of our study was to investigate whether the insertion/deletion polymorphism in Angiotensin-converting enzyme gene is associated with ischemic stroke in a South Indian population. One hundred and sixty two patients and one hundred and fifty controls were studied for the presence of ACE gene polymorphism by PCR technique. The stroke patients were subtyped according to TOAST criteria, taking into account all the available data. There were significant differences in the genotypic distribution and allelic frequency between the patients and healthy controls. Furthermore the D allele was significantly associated with intracranial large artery atherosclerosis. However, the association was insignificant with other stroke subtypes. We observed that ACE ID/DD genotypes are associated with an elevated incidence of stroke in a South Indian population from Andhra Pradesh. Moreover, ACE gene polymorphism was found to contribute to the risk of developing intracranial large artery atherosclerosis, which is the most frequent subtype in this region.

ACE I/D polymorphism in Korean patients with ischemic stroke and silent brain infarction

OBJECTIVES

Angiotensin-converting enzyme (ACE) polymorphism may play a role in stroke and silent brain infarction (SBI) susceptibility, but the results among the populations studied to date have not been consistent. Thus, we investigated the association between ACE genotypes and ischemic stroke and SBI in Korean patients.

SUBJECTS AND METHODS

DNA samples from 237 stroke patients, 264 SBI patients and 234 age-matched controls were amplified using polymerase chain reaction to detect the ACE ins/del (I/D) polymorphism. Genotype was determined by the presence of a 490-bp band (I allele) or a 190-bp band (D allele) in agarose gel electrophoresis.

RESULTS

Odds ratios of the I/D and D/D genotypes and the overall (I/D + D/D) for the I/I genotype were significantly different between stroke patients and normal controls. However, there was no significant difference between patients with SBI and controls.

CONCLUSIONS

This study is the first report of a significant association between ACE polymorphism and ischemic stroke in the Asian population. Although no consistent associations have been found between ACE polymorphism and stroke in the populations studied to date, the ACE polymorphism may be a genetic determinant of ischemic stroke, at least in Korean patients.

Interaction of angiotensin-converting enzyme and apolipoprotein E gene polymorphisms in ischemic stroke involving large-vessel disease

A relationship between apolipoprotein E (Apo E) genotype and angiotensin-converting enzyme (ACE) insertion-deletion (Ins-Del) mutation and stroke was suggested. We investigated the association of Apo E4 and ACE Ins/Del genotypes with stroke risk and changes in serum lipids in 228 consecutive Tunisian stroke patients, and 323 age-and gender-matched controls. Comparable frequencies of ACE Ins/Del alleles were seen between patients and controls. The prevalence of Apo epsilon3 allele and Apo E3/E3 were lower (P < 0.001), while the frequency of Apo epsilon4 allele and epsilon4-containing genotypes (E3/E4 and E4/E4) were elevated (P < 0.001) among patients. Higher proportion of Apo E4-carrying + ACE Del/Del positive cases were seen in young (<50 years) patients (P = 0.012), and was associated with large vessel stroke (P = 0.035). Mean serum cholesterol, LDL, HDL, and triglycerides were comparable between E4-containing and no E4-containing and ACE Del/Del-positive patients. Apo E4 and ACE Del/Del genotype combination substantially increase stroke risk, supporting the notion that interactions of multiple gene variants influence stroke pathogenesis.