Association of methylenetetrahydrofolate reductase (MTHFR) rs1801133 (677C>T) gene polymorphism with ischemic stroke risk in different populations: An updated meta-analysis

Background: Recently, increasing evidence has implicated methylenetetrahydrofolate reductase (MTHFR) gene mutation as a risk factor for ischemic stroke (IS) in the general population. However, studies have been inconclusive and lack evidence on specific populations. We aim to determine whether the rs1801133 (NC_000001.11 (MTHFR):g. 677C>T (p.Ala222Val) variant, we termed as MTHFR rs1801133 (677 C>T), is linked to an increased risk of IS in different age groups and ancestry groups. Methods: The literature relevant to our study was found by searching the PubMed, Cochrane Library, Web of Science, EMBASE, and CNKI databases. A random effect model analysis was used to calculate the pooled odds ratio (OR) and 95% confidence interval (CI) to evaluate any possible association. We conducted a subgroup analysis based on the age and ancestry groups of the included populations. Results: As of March 2022, 1,925 citations had been identified in electronic databases, of which 96 studies involving 34,814 subjects met our eligibility criteria. A strong link was found between IS and the MTHFR gene rs1801133 (677C>T) polymorphism in all genetic models [dominant genetic model (OR = 1.47; 95%CI = 1.33-1.61; p < 0.001), recessive genetic model (OR = 1.52; 95%CI = 1.36-1.71; p < 0.001), heterozygous model (OR = 1.36; 95%CI = 1.24-1.48; p < 0.001), homozygous model (OR = 1.82; 95%CI = 1.58-2.11; p < 0.001), and T allelic genetic model (OR = 1.37; 95%CI = 1.27-1.48; p < 0.001)]. Further subgroup analyses indicated that the MTHFR rs1801133 (677C>T) variant may increase the risk of IS in Asian, Hispanic, or Latin population, middle-aged, and elderly populations (p < 0.001). Conclusion: Our results implied that mutation of the T allele of MTHFR rs1801133 (677C>T) could be a risk factor for IS. A significant association was found among Asian, Hispanic, or Latin population, middle-aged, and elderly people.

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.

Thrombophilia screening in young patients with cryptogenic stroke

The clinical relevance of thrombophilia screening in stroke patients is still a matter of debate, and descriptions of larger patterns of genetic variability are rare. We assessed the frequency of hereditary hypercoagulability in young patients with cryptogenic stroke (n = 44) and in healthy blood donors (n = 282) without prior cardiovascular event. Furthermore, we focused on the impact of thrombophilia screening on secondary stroke prevention. Results: Compared to the control group (19–67 years; median 38.5 years; 64% women), there was a lower prevalence of the FVII-R353Q mutation (p = 0.033) in stroke patients (17–52 years; median 36 years; 59.1% women). Of note, the FVII-R353Q mutation lowers FVII plasma levels, probably reducing the risk of cardiovascular events. The prevalence of the remaining 13 gene polymorphisms did not differ significantly. However, the prevalence of FV Leiden mutation tended to be higher among stroke patients. Conclusion: Overall, extended screening for inherited thrombophilia had an impact on medical stroke prevention in every sixth patient with cryptogenic stroke.

The effect of angiotensin-converting enzyme polymorphism on hemodynamic response to endotracheal intubation in hypertensive patients

Endotracheal intubation elicits a hemodynamic response associated with increased heart rate and blood pressure that is influenced by the angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) genetic polymorphism which may be of importance also for the pressure response to anesthesia. A total of 337 patients underwent abdominal surgery in general anesthesia and 16% were D/D-homozygotes, 45% were I/D heterozygotes and 39% of the patients were I/I homozygotes. Before surgery most patients were in treatment for arterial hypertension. Systolic and diastolic pressure, heart rate and concentrations of catecholamines in blood were determined before and after induction of anesthesia and for up to 10 minutes following endotracheal intubation. Anesthesia decreased blood pressure and for patients presenting ID and DD, blood pressure and heart rate reached similar levels but compared to II-homozygotes, D-carriers demonstrated significantly higher levels for systolic pressure and heart rate before and after intubation (p < 0.05). The blood levels of catercholamines were similar in the three genotype groups. The incidence of ECG-determined myocardial ischemia was higher in D-allele carriers compared to I-allele homozygotes (DD 22%, ID 25% vs. II 5%). In response to anesthesia and intubation and independent of sympathetic nervous activity, D-allele carriers for ACE polymorphism increased blood pressure response and higher risk for development of cardiovascular complications compared to patients homozygous for the I-allele.

Evaluation of Factor V Leiden, Prothrombin G20210A, MTHFR C677T and MTHFR A1298C gene polymorphisms in retinopathy of prematurity in a Turkish cohort

BACKGROUND

To assess Factor V Leiden (FVL) (rs6025), Prothrombin G20210A (rs1799963), MTHFR C677T (rs1801133), and MTHFR A1298C (rs1801131) gene mutations as risk factors in the development of retinopathy of prematurity (ROP).

MATERIALS AND METHODS

A total of 105 children were included in this cross-sectional study. Patients were divided into two groups. The study group consisted of 55 infants with a history of ROP and the control group comprised 50 healthy infants with term birth. All subjects were screened for the presence of certain mutations (FVL, Prothrombin G20210A, MTHFR C677T and MTHFR A1298C) by Real-Time PCR at 1 year of age.

RESULTS

The mean gestational age (GA) and birth weight (BW) of the study group were, 28.65 ± 2.85 weeks and 1171 ± 385.74 g, respectively. There were no significant differences of genotype and allele frequency of Prothrombin G20210A, MTHFR A1298C and MTHFR C677T between the study and control groups (p > 0.05). Eight children (14.5 %) had heterozygous and one child (1.8%) had homozygous FVL mutation in the study group. One child (2%) in the control group had heterozygous FVL mutation. There was statistically significant differences of FVL allele and genotype frequencies between the groups (p < 0.05).

CONCLUSIONS

The prevalence of FVL polymorphism (16.3 %) was higher in ROP patients than control subjects in this Turkish cohort. We suggest a possible association of FVL mutation with ROP at the end of the study.

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.

Role of ACE I/D gene polymorphisms on the effect of ramipril in inflammatory response and myocardial injury in patients undergoing coronary artery bypass grafts

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibitors block angiotensin II formation and release bradykinin, which is effective in the regulation of oxidoinflammatory injury. Some reports denote alterations in the effectiveness of ACE inhibitors in association with ACE insertion/deletion (I/D) gene polymorphisms. This study investigates the effects of ramipril on the oxidoinflammatory cytokines (IL-6, IL-8, TNF-alpha) and TnT (myocardial injury marker) and their alteration in association with ACE I/D gene polymorphisms.

METHODS

The study group (n = 51) patients received ramipril before coronary artery bypass grafting (CABG), while patients not receiving ramipril (n = 51) constituted the controls. TNFα, IL-6, and IL-8 were evaluated using ELISA and TnT by electrochemiluminescence methods before the induction of anesthesia (t1), at the 20th minute following cross-clamping (t2), at the end of the operation (t3), and at the 24th hour from the commencement of anesthesia (t4). Genotyping was performed by PCR.

RESULTS

Differences between the groups were significant at t4 for the TNFα and at t3 for IL-6 (p < 0.05). The TnT levels increased from t2 onward in the control group and were highest in t3. Changes in t3 and t4 values in both groups according to their t1 values were significant (p < 0.05). However, differences between the groups were insignificant (p > 0.05). The IL-6, IL-8, TNFα, and TnT serum levels had no correlation with the ACE I/D gene polymorphism.

CONCLUSION

Low cytokine and TnT levels in the study group, especially after cross-clamping, may indicate the protective effect of ramipril from oxidoinflammatory injury. This effect did not appear to be associated with the ACE I/D gene polymorphism.

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.

Association between polymorphism of MTHFR c.677C>T and risk of cardiovascular disease in Turkish population: a meta-analysis for 2.780 cases and 3.022 controls

Cardiovascular diseases (CVDs) remain the main cause of morbidity and mortality around the world. A common polymorphism c.677C>T has been identified in the gene coding for methylenetetrahydrofolate reductase (MTHFR), which is involved in the remethylation of homocysteine, and may predispose to CVDs. A meta-analysis was performed to estimate the risk of CVDs associated with MTHFR c.677C>T in Turkish population. Published studies were retrieved from PubMed, Science Citation Index/Expanded, Google Scholar, Turkish Medline, and the Turkish Council of Higher Education Theses Database. For each study, we calculated odds ratios and 95 % confidence intervals (CI), assuming frequency of allele and homozygote comparison, dominant and recessive genetic models. Thirty-one separate studies were included and 2.780 cases/3.022 controls were involved in the current meta-analysis. Significant association was found between c.677C>T polymorphism and risk of CVD when all studies pooled with random-effects model for T versus C (OR 1.33; 95 % CI 1.11-1.59; p = 0.002), TT vs. CC (OR 1.87; 95 % CI 1.35-2.60; p = 3.53E-04), TT+CT vs. CC (OR 1.32; 95 % CI 1.06-1.64; p = 0.014) and TT vs. CT+CC (OR 1.75; 95 % CI 1.29-2.37; p = 6.57E-04). Further analysis indicated the significant association between methylenetetrahydrofolate reductase (MTHFR) TT genotype and groups with venous thrombosis, peripheral arterial thrombosis, acute MI/MI. No publication bias was observed in any comparison model. Our results of meta-analysis suggest that MTHFR c.677C>T polymorphism is associated with the CVDs in Turkish population.

Angiotensin I-converting enzyme gene (I/D) polymorphism in patients with migraine

In addition to the wide expression in many tissues including vascular endothelial cells, production of angiotensin II and degradation of bradykinin may indicate that angiotensin-converting enzyme could be involved in vascular tension and blood pressure. It has been reported that the deletion allele of the angiotensin-converting enzyme gene is associated with increased serum angiotensin-converting enzyme levels and linked to cerebrovascular diseases. In this study, the possible association of migraine with aura with the angiotensin-converting enzyme deletion-deletion (DD) and the angiotensin-converting enzyme insertion-deletion (ID) genotype was investigated in Turkish patients. To investigate the role of the angiotensin-converting enzyme I/D polymorphism in Turkish patients with migraine with aura, we analyzed the I/D genotype of 53 patients with that disorder. Twenty-two control subjects, who are volunteer Turkish patients without migraine, were included in the study. The frequency of the angiotensin-converting enzyme D/D genotype was statistically significant more frequent in patients with migraine with aura (81.1%) than in controls (59.1%) (P < .05). No differences were found regarding the I/I genotype and the I/D genotype between the 2 groups (P > .05). The results of our study revealed that the angiotensin-converting enzyme D/D genotype was more frequent in patients with migraine with aura than in controls. This might suggest that the angiotensin-converting enzyme D/D genotype may be a genetic risk factor for migraine with aura in Turkish patients.

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.

Epidemiology of activated protein C resistance and factor v leiden mutation in the mediterranean region

Venous thromboembolic disorders (VTE) are serious disorders with high morbidity and mortality rates. Many genetic and acquired risk factors were identified to cause VTE. The most common genetic risk factor is Factor V Leiden mutation (FVL). FVL was found in high percentage of populations of Caucasian origin but was almost absent in non-Caucasians. It was also reported in populations living in North Africa and the Middle East. This review article briefly explains FVL and how it causes VTE, the distribution of FVL worldwide, and then it elaborates on the epidemiology of FVL in the Mediterranean Region and how this brought speculations that FVL might have originated in the Eastern Mediterranean area.

The role of plasminogen activator inhibitor-1 and angiotensin-converting enzyme gene polymorphisms in bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a multifactorial disease of preterm infants that is characterized by airway injury, inflammation, and parencymal remodeling. Activation of the coagulation cascade leads to intraalveolar fibrin deposition in many inflammatory pulmonary disorders. Increased fibrin formation or decreased fibrinolysis may cause extravascular fibrin deposition. Extravascular fibrin deposits in septae and alveoli due to the altered fibrin turnover are the pathological hallmarks of BPD, which strongly indicate the importance of the imbalance in the competing activities of coagulation and fibrinolysis.

OBJECTIVE

We investigated the predictive value of variations in plasminogen activator inhibitor-1 (PAI-1) and angiotensin-converting enzyme (ACE) genes as molecular determinants for BPD in neonates.

METHODS

The study group comprised 98 preterm infants with BPD and a control group including 94 preterm infants without BPD. Restriction fragment size analyses were performed by visualizing digested polymerase chain reaction products for ACE and PAI-1 genotypes.

RESULTS

No significant associations were found between ACE, PAI-1 gene polymorphisms, and BPD phenotype in our population.

CONCLUSIONS

The two gene polymorphisms (PAI-1 and ACE) had no role in the development of BPD in our study. Further studies with other genes are required for the identification of molecular predisposing factors for BPD that may help in the development of new treatments.