A DNA variant at the angiotensin-converting enzyme gene locus associates with coronary artery disease in the Caerphilly Heart Study

The resistance to methoxy polyethylene glycol-epoetin beta in anemic patients of end-stage renal disease

Background

Chronic kidney disease (CKD) is a global disease, and the number of people affected is increasing due to driving factors such as diabetes, obesity, and hypertension, as well as increased life expectancy. Many patients with CKD suffer anemia throughout the period of their disease.

Aim

This research aimed to investigate the relation between resistance to the methoxy polyethylene glycol-epoetin beta (ME-β) and angiotensin-converting enzyme (ACE) gene polymorphism.

Methods

Seventy Iraqi patients with CKD on hemodialysis treatment for at least six months and receiving a subcutaneous injection of ME-β were selected to enroll in this current study. In addition to these patients, the control group of 20 healthy subjects. Baseline samples (Three blood samples) were obtained and withdrawn from each participant, then 3 and 6 months following the starting sample. In addition, a unique blood sample was taken from each participant in the control group in the early morning hours following 8 h of fasting and before dialysis (for the patients' group).

Results

ACE polymorphism did not demonstrate a significant (p ˃ 0.05) relation with changing the dose of ME-β. Furthermore, there was a negative relationship between ME-β dose and hemoglobin (Hb) in CKD patients. Comparing ACE polymorphism between good and hypo-response groups shows no significant effect (p ˃ 0.05) on ME-β therapy. Moreover, the erythropoietin resistance index (ERI) was significantly (p < 0.001) lower in good responders to ME-β therapy compared to the hypo-response group. Finally, comparing the ERI of the patient, the good response group to the hypo-response group showed no significant association (p ˃ 0.05) with ACE gene polymorphism in response to ME-β therapy.

Conclusion

No relation was determined between the polymorphism ACE gene and the resistance to the ME-β administration in CKD Iraqi patients.

Angiotensin-Converting Enzyme Gene Polymorphism and Erythropoietin Requirement

Objectives

To study the effect of angiotensin-converting enzyme (ACE) polymorphisms II, ID, and DD on erythropoietin (EPO) requirement in patients on continuous ambulatory peritoneal dialysis (CAPD) therapy.

Design

Retrospective observational study.

Setting

CAPD Unit, Royal London/St. Bartholomews Hospital, London, UK.

Patients

46 patients on the transplant waiting list (age 20 – 70 years), on CAPD therapy for an average of 28 months, seen consecutively over a period of 3 months in the outpatients department.

Main Outcome Measures

Primary end point: EPO dose requirement in different ACE genotypes. Secondary end points: C-reactive protein, ferritin, parathyroid hormone, Kt/V, duration of dialysis, folate, cause of renal failure, and whether or not patients were on ACE inhibitor therapy.

Results

There was a statistically significant difference ( p < 0.05) in EPO requirement in the II/ID group compared to the DD group. The mean ± standard error of EPO for the II/ID group was 144 ± 15 U/kg/week, and for the DD group, 87 ± 9 U/kg/ week. The difference in EPO requirement could not be explained by age, C-reactive protein, ferritin, parathyroid hormone, Kt/V, duration of dialysis, folate, cause of renal failure, or whether or not patients were on ACE inhibitor therapy.

Conclusion

In CAPD patients, ACE genotype has predictive value when determining the EPO dosage, as the II/ID genotype may be associated with a suboptimal response.

The Effect of Proinflammatory Cytokine Gene and Angiotensin-Converting Enzyme Polymorphisms on Erythropoietin Requirements in Patients on Continuous Ambulatory Peritoneal Dialysis

Background

The correction of anemia by recombinant human erythropoietin (rHuEPO) improves quality of life and prolongs life in end-stage renal failure. rHuEPO requirements for an individual are determined by a range of factors, including iron deficiency and inflammation. Single nucleotide polymorphisms in the promoter sequence of several proinflammatory cytokines have been shown, in different fields of medicine, to influence the cytokine response to different stimuli, with effects on clinical outcome.

Methods

The angiotensin-converting enzyme (ACE) insertion/deletion polymorphism and polymorphisms in the promoter regions of the genes for tumor necrosis factor alpha (-308 A/G), interleukin-6 (-174 G/C), and interferon gamma were examined for their association with rHuEPO requirements in 112 patients on continuous ambulatory peritoneal dialysis (CAPD). Genomic DNA was extracted from peripheral blood leukocytes and genotyping performed with ARMS-PCR methodology, with sequence-specific primers. We examined rHuEPO requirements and C-reactive protein at baseline and during a 6-month study period.

Results

We found no significant effect of proinflammatory cytokine polymorphisms on rHuEPO responsiveness. However, throughout the study, we observed that there was a significantly higher rHuEPO requirement in the II and ID ACE genotypes compared with the DD group, which remained an independent association following multivariate analysis.

Conclusions

ACE insertion/deletion polymorphism may determine rHuEPO responsiveness in CAPD patients and should be considered in relative rHuEPO resistance.

ACE gene polymorphism and its association with serum erythropoietin and hemoglobin ‎in Iraqi hemodialysis patients

Purpose

To evaluate the frequencies of angiotensin-converting enzyme gene ‎polymorphism in ‎Iraqi hemodialysis patients and to examine the association ‎between this polymorphism and ‎serum erythropoietin and hemoglobin levels.‎.

Methods

In this study, 70 chronic renal failure Iraqi patients on ‎maintenance ‎hemodialysis (patient group) and 20 healthy subjects (control ‎group) were genotyped for ‎angiotensin-converting enzyme gene polymorphism. The distribution of genotype and allele ‎frequencies of this polymorphism in ‎these subjects were also evaluated.‎.

Results

The distribution of angiotensin-converting enzyme genotypes between ‎groups was ‎similar, and the ID genotype was the most frequent, followed by DD and II ‎genotypes (‎50%‎, ‎37%‎, and ‎13%). The control group ‎had a nonsignificant difference in serum ‎erythropoietin levels among different angiotensin-converting enzyme genotypes, ‎while patients with ID and DD genotypes displayed significant ‎elevation in ‎serum erythropoietin with time. No significant differences in hemoglobin ‎levels ‎were observed in patient and control groups. A significant positive correlation ‎was ‎observed between serum erythropoietin and hemoglobin in the control group ‎with different ‎angiotensin-converting enzyme genotypes, while a nonsignificant ‎negative correlation was ‎observed in the patient group throughout the study. ‎.

Conclusions

Chronic kidney disease did not significantly alter angiotensin-converting enzyme ‎genotypes, and angiotensin-converting enzyme gene ‎polymorphism had a significant effect on ‎serum erythropoietin levels and a non‎significant effect on hemoglobin levels. ‎.

The Angiotensin Converting Enzyme I/D Polymorphism in Turkish Athletes and Sedentary Controls

The angiotensin converting enzyme (ACE) gene is located on human chromosome 17 expressing three genotypes within the intron 16 of the related gene structure. These genotypes are classified as I and D alleles which are termed as insertion and deletion, respectively. This study was carried out to identify possible relationships between the insertion/ deletion (I/D) polymorphisms and athletic performance in Turkish athletes. To be able to determine these relationships, eighty healthy athletes and eighty healthy sedentary controls were genotyped for the ACE I/D polymorphism at gene level. According to the results obtained, we found significant difference on ACE I/D polymorphism in between athletes and healthy controls (x2 = 7.32, df = 2, P = 0.026). This result supports the association in ACE genotype in Turkish athletes, suggesting that this might be a genetic factor influencing the physical performance.

Impact of I/D polymorphism of angiotensin-converting enzyme (ACE) gene on myocardial infarction susceptibility among young Moroccan patients

Objective

Our case–control study aimed to access the potential association of insertion/deletion (I/D) ACE (angiotensin converting enzyme) gene polymorphism with myocardial infarction (MI) risk of occurrence among a sample of Moroccan patients, especially young ones.

Results

Distribution of I/D ACE gene variant among cases vs controls, showed that healthy controls carried out higher frequency of wild type allele I compared to cases (23.5% vs 21.79% respectively), when cases were carrying higher frequency of mutant allele D (78.21% vs 76.5% for controls). Patients were-after this- divided into two groups of < 45 and > 55 years of age, to investigate whether or not younger patients carried out higher frequency of the mutant allele D, than older ones. As expected, < 45 years old patients carried out more DD genotype than older ones (68.9% vs 54.6% respectively), and higher frequency of mutant allele D (81.08% vs 75% respectively). Besides, a tendency to a positive association was found under the recessive genetic transmission model (OR [95% CI] = 1.85 [0.93–3.69], P = 0.08), suggesting that the I/D ACE polymorphism may be associated with MI occurrence among younger patients (< 45 years of age).

Electronic supplementary material

The online version of this article (10.1186/s13104-017-3039-1) contains supplementary material, which is available to authorized users.

High-Saturated-Fat Diet Increases Circulating Angiotensin-Converting Enzyme, Which Is Enhanced by the rs4343 Polymorphism Defining Persons at Risk of Nutrient-Dependent Increases of Blood Pressure

BACKGROUND

Angiotensin-converting enzyme (ACE) plays a major role in blood pressure regulation and cardiovascular homeostasis. Contrary to the assumption that ACE levels are stable, circulating ACE has been shown to be altered in obesity and weight loss. We sought to examine effects of a high-saturated-fat (HF) diet on ACE within the NUtriGenomic Analysis in Twins (NUGAT) study.

METHODS AND RESULTS

Forty-six healthy and nonobese twin pairs initially consumed a carbohydrate-rich, low-fat diet over a period of 6 weeks to standardize for nutritional behavior prior to the study, followed by 6 weeks of HF diet under isocaloric conditions. After 6 weeks of HF diet, circulating ACE concentrations increased by 15% (P=1.6×10^-30), accompanied by an increased ACE gene expression in adipose tissue (P=3.8×10^-6). Stratification by ACE rs4343, a proxy for the ACE insertion/deletion polymorphism (I/D), revealed that homozygous carriers (GG) of the variant had higher baseline ACE concentrations (P=7.5×10^-8) and additionally showed a 2-fold increase in ACE concentrations in response to the HF diet as compared to non- or heterozygous carriers (AA/AG, P=2×10^-6). GG carriers also responded with higher systolic blood pressure as compared to AA/AG carriers (P=0.008). The strong gene-diet interaction was confirmed in a second independent, cross-sectional cohort, the Metabolic Syndrome Berlin Potsdam (MeSyBePo) study.

CONCLUSIONS

The HF-diet-induced increase of ACE serum concentrations reveals ACE to be a potential molecular link between dietary fat intake and hypertension and cardiovascular disease (CVD). The GG genotype of the ACE rs4343 polymorphism represents a robust nutrigenetic marker for an unfavorable response to high-saturated-fat diets.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01631123.

Deciphering the genetic and modular connections between coronary heart disease, idiopathic pulmonary arterial hypertension and pulmonary heart disease

Coronary heart disease (CHD), idiopathic pulmonary arterial hypertension (IPAH) and pulmonary heart disease (PHD) are circulatory system diseases that may simultaneously emerge in a patient and they are often treated together in clinical practice. However, the molecular mechanisms connecting these three diseases remain unclear. In order to determine the multidimensional characteristic correlations between these three diseases based on genomic networks to aid in medical decision-making, genes from the Online Mendelian Inheritance in Man database were obtained, and applied network construction and modularized analysis were conducted. Functional enrichment analysis was conducted to explore the associations between overlapping genes, modules and pathways. A total of 29 overlapping genes and 3 common modules were identifed for the 3 diseases. Glycosphingolipid biosynthesis and the arachidonic acid metabolism are common pathways, and the biosynthetic process is suggested to be the major function involved in the three diseases. The current study reported, to the best of our knowledge for the first time, the role of glycosphingolipid biosynthesis in IPAH and PHD. The present study provided an improved understanding of the pathological mechanisms underlying CHD, IPAH and PHD. The overlapping genes, modules and pathways suggest novel areas for further research, and drug targets. The observations of the current study additionally suggest that drug indications can be broadened because of the presence of common targets.

The Renin-Angiotensin and fibrinolytic systems co-conspirators in the pathogenesis of ischemic cardiovascular disease

In vitro and in vivo data provide evidence for an interaction between the renin-angiotensin and fibrinolytic systems. Angiotensin-converting enzyme (ACE) is strategically poised to regulate this interaction. ACE catalyzes the conversion of angiotensin I to angiotensin II (Ang), and Ang II stimulates release of PAI-1, the major inhibitor of tissue-type plasminogen activator (t-PA) and urokinase in the vasculature. Conversely, ACE catalyzes the breakdown of bradykinin, a potent stimulus of t-PA secretion. This interaction between the renin-angiotensin and fibrinolytic systems may partially explain the clinical observation that stimulation or suppression of the renin-angiotensin system can alter the risk of ischemic cardiovascular events. © 1996, Elsevier Science Inc. (Trends Cardiovasc Med 1996;6:239-243).

Coronary Calcification and Hormones

The pathogenesis of coronary artery calcification and its role in atherogenesis has not been completely understood but is a new focus of interest in experimental and clinical research. Various bioactive substances, including hormones, have been implicated in the process of arterial calcification. This review considers the relationship between coronary artery calcification and hormones. These hormones may become therapeutic targets for the prevention of arterial calcification.

The association between circulating angiotensin-converting enzyme and cardiovascular risk in the elderly: a cross-sectional study

INTRODUCTION

A polymorphism in the angiotensin-converting enzyme gene (ACE I/D polymorphism) has been associated with increased risk for cardiovascular disease (CVD). This polymorphism affects the level of circulating ACE, but there is great individual variation, even between those with the same genotype. Few previous studies have investigated the link between circulating ACE and cardiovascular risk. The aim of this study was to investigate this association, and to examine the relationship between ACE level, ACE genotype and CVD.

MATERIALS AND METHODS

The study population consisted of 322 men and 350 women aged 69-87. Plasma ACE level was determined using enzyme-linked immunosorbent assay (ELISA), and ACE genotype was analysed using PCR followed by gel electrophoresis.

RESULTS

In men, ACE levels increased with increasing number of cardiovascular risk factors (p = 0.003). There was a significant association in men between increased ACE level and both diabetes (p = 0.007) and smoking (p = 0.037).

CONCLUSIONS

This study shows that cardiovascular risk factors (such as smoking and diabetes) are associated with higher levels of circulating ACE in men. High ACE levels may represent one of the cellular mechanisms involved in producing the vascular damage associated with cardiovascular risk factors.

Genetically determined angiotensin converting enzyme level and myocardial tolerance to ischemia

Angiotensin I-converting enzyme (ACE; kininase II) levels in humans are genetically determined. ACE levels have been linked to risk of myocardial infarction, but the association has been inconsistent, and the causality underlying it remains undocumented. We tested the hypothesis that genetic variation in ACE levels influences myocardial tolerance to ischemia. We studied ischemia-reperfusion injury in mice bearing 1 (ACE1c), 2 (ACE2c, wild type), or 3 (ACE3c) functional copies of the ACE gene and displaying an ACE level range similar to humans. Infarct size in ACE1c was 29% lower than in ACE2c (P<0.05). Pretreatment with a kinin B2 receptor antagonist suppressed this reduction. In ACE3c, infarct size was the same as in ACE2c. But ischemic preconditioning, which reduced infarct size in ACE2c (-63%, P<0.001) and ACE1c (-52%, P<0.05), was not efficient in ACE3c (-2%, NS, P<0.01 vs. ACE2c). In ACE3c, ischemic preconditioning did not decrease myocardial inflammation or cardiomyocyte apoptosis. Pretreatment with a renin inhibitor had no cardioprotective effect in ACE2c, but in ACE3c partially restored (38%) the cardioprotection of ischemic preconditioning. Thus, a modest genetic increase in ACE impairs myocardial tolerance to ischemia. ACE level plays a critical role in cardiac ischemia, through both kinin and angiotensin mediated mechanisms.

Genetically determined angiotensin converting enzyme level and myocardial tolerance to ischemia

Angiotensin I-converting enzyme (ACE; kininase II) levels in humans are genetically determined. ACE levels have been linked to risk of myocardial infarction, but the association has been inconsistent, and the causality underlying it remains undocumented. We tested the hypothesis that genetic variation in ACE levels influences myocardial tolerance to ischemia. We studied ischemia-reperfusion injury in mice bearing 1 (ACE1c), 2 (ACE2c, wild type), or 3 (ACE3c) functional copies of the ACE gene and displaying an ACE level range similar to humans. Infarct size in ACE1c was 29% lower than in ACE2c (P<0.05). Pretreatment with a kinin B2 receptor antagonist suppressed this reduction. In ACE3c, infarct size was the same as in ACE2c. But ischemic preconditioning, which reduced infarct size in ACE2c (-63%, P<0.001) and ACE1c (-52%, P<0.05), was not efficient in ACE3c (-2%, NS, P<0.01 vs. ACE2c). In ACE3c, ischemic preconditioning did not decrease myocardial inflammation or cardiomyocyte apoptosis. Pretreatment with a renin inhibitor had no cardioprotective effect in ACE2c, but in ACE3c partially restored (38%) the cardioprotection of ischemic preconditioning. Thus, a modest genetic increase in ACE impairs myocardial tolerance to ischemia. ACE level plays a critical role in cardiac ischemia, through both kinin and angiotensin mediated mechanisms.

Are polymorphisms in the ACE and PAI-1 genes associated with recurrent spontaneous miscarriages?

PROBLEM

To determine whether the ACE D/D genotype or the combination of PAI-1 4G/4G and ACE D/D genotypes may serve as a risk factor for recurrent pregnancy loss.

METHOD OF STUDY

Buccal swabs were obtained from 120 women experiencing recurrent pregnancy loss and from 84 fertile control women. DNA was extracted from the buccal swab samples using the Qiagen DNA Mini Kit (Qiagen), followed by multiplex polymerase chain reaction (PCR). PCR products were analyzed for the ACE gene polymorphism, which consists of the insertion or deletion (I/D) of a 287-bp fragment in intron 16, and the PAI-1 4G/4G genotype.

RESULTS

No significant differences in specific ACE gene mutations were observed when patients experiencing recurrent miscarriage were compared with control women. When the frequencies of homozygous mutations for ACE D/D and PAI-I 4G/4G were compared between recurrent aborters and controls, again no significant differences in the prevalence of the combination of these gene mutations were noted.

CONCLUSION

Homozygosity for the D allele of the ACE gene and the combination of the D/D genotype with two 4G alleles of the PAI-1 promoter gene are not associated with a significant increase in the risk of recurrent miscarriage.

Relationship between ACE-DD polymorphism and diastolic performance in healthy subjects

BACKGROUND

The ACE-D allele has been associated with cardiovascular disease. The study evaluates the relationship between the ACE-ID genotypes and diastolic function in healthy subjects after 6 years of follow-up.

METHODS

Two hundred and seventy-five healthy volunteers aged 25-55 years had normal physical examination, 12-lead ECG, acceptable echocardiographic windows and echocardiogram at entry. Venous blood was drawn for DNA analysis.

RESULTS

Two hundred and forty-two subjects completed 6 years of follow-up. Three genetically distinct groups were obtained: ACE-DD group (n=71, 26F/45M, mean age 48 +/- 7 years); ACE-ID (n=115, 39F/76M, mean age 40 +/- 7 years); and ACE-II (n=56, 20F/36M, mean age 47 +/- 6 years). Significant differences in E/A ratio were found between ACE-DD and ACE-ID, and ACE II (p=0.028, <0.0001, 0.0001), respectively. After 6 years, echocardiography showed a significant reduction of E/A ratio in the ACE-DD group, p=0.0001.

CONCLUSION

The data suggest that ACE-DD is associated with deteriorating myocardial diastolic properties.

Association of genetic polymorphisms in the ACE, ApoE, and TGF beta genes with early onset ischemic heart disease

BACKGROUND

The genetic factors that contribute to ischemic heart disease (IHD) are poorly understood, and it is likely that multiple genes acting independently or synergistically contribute to the risk of IHD and outcome. The genes for angiotensin-converting enzyme (ACE) and apolipoprotein E (ApoE) have been implicated independently in the risk of IHD.

HYPOTHESIS

This study examined whether genetic polymorphisms in the ACE and ApoE genes are associated with early onset IHD. Polymorphisms in a third gene, transforming growth factor beta 2 (TGF beta 2), with a known role in wound repair and cardiac development, are also examined with respect to early onset IHD.

METHODS

In all, 101 patients with IHD and onset of disease before 55 years for men and 60 years for women, and 100 controls with angiographically confirmed normal coronary arteries were recruited for this study. The ACE, ApoE, and TGF beta 2 genotypes were determined by polymerase chain reaction amplification or Southern blotting and were compared with the patient's clinical and family histories.

RESULTS AND CONCLUSION

The frequency of the ACE D allele was significantly lower in the patient group (0.475) than in the control group (0.59, p = 0.03), which was attributed to a reduction in the number of patients with the DD genotype (patients: 24% DD, controls: 33% DD). Sudden cardiac death was also associated with the DD genotype. These data are consistent with the ACE D allele contributing to a fatal outcome. No association between the DD genotype and risk of myocardial infarction, presenting age, extent of vessel disease, family history, hypertension, or hypercholesterolemia was seen. Analysis of the ApoE genotype showed no association with early onset IHD. There was no evidence for a synergistic effect between the ACE and ApoE genotypes on the risk of early onset IHD. A polymorphism in the TGF beta 2 gene was rare and not associated with early onset IHD.

Role of angiotensin converting enzyme, paraoxonase 1 55, 192 gene polymorphisms in syndrome X and coronary heart disease

Aim of this study was to investigate the possible relationship between ACE and/or PON1 M55L, Q192R genetic polymorphisms and subjects with Coronary Heart Disease (CHD) and/or syndrome X (SX) when compared to the control group. ACE I/D, PON1 M55L and Q192R genetic polymorphisms, Body Mass Index (BMI) and biochemical parameters were investigated in subjects with CHD (n = 19), SX (n = 34) and healthy subjects (n = 26). All of the subjects were nonsmokers. According to the unrelated group t-test results; BMI, HDL-C and TG values were found to be slightly different in SX and control subjects but there was no significant difference in LDL-C and TC values. According to the Mann Whitney U-test results, BMI, TC, HDL-C and LDL-C values were found to be significantly different among CHD and control group subjects, but there was no difference in TG values. The results of this study indicates that ACE, PON1 192 and PON1 55 gene polymorphisms are not related to genetic susceptibility to SX and/or CHD in non-smokers. Obviously, the interpretation of these finding is difficult due to the small sample size and larger group studies are needed for more definitive conclusions.

RAS gene polymorphisms, classical risk factors and the advent of coronary artery disease in the Portuguese population

Background

Several polymorphisms within the renin-angiotensin system cluster of genes have been associated with the advent of coronary artery disease (CAD) or related pathologies. We investigated the distribution of 5 of these polymorphisms in order to find any association with CAD development and distinguish if any of the biochemical and behavioural factors interact with genetic polymorphisms in the advent of the disease.

Methods

ACE I/D (rs4340), ACE A11860G (rs4343), AT1R A1166C (rs5186), AGT T174M (rs4762) and AGT M235T (rs699) gene polymorphisms were PCR-RFLP analysed in 298 CAD patients and 510 controls from Portugal. Several biochemical and behavioural markers were obtained.

Results

ACE I/D DD and ACE11860 GG genotypes are risk factors for CAD in this population. The simultaneous presence of ACE I/D I and ACE11860 A alleles corresponds to a significant trend towards a decrease in CAD incidence. We found several synergistic effects between the studied polymorphisms and classical risk factors such as hypertension, obesity, diabetes and dyslipidaemia: the presence of the DD genotype of ACE I/D (and also ACE11860 GG) increases the odds of developing CAD when associated to each one of these classical risk factors, particularly when considering the male and early onset CAD subgroup analysis; AGT235 TT also increases the CAD risk in the presence of hypertension and dyslipidaemia, and AT1R1166 interacts positively with hypertension, smoking and obesity.

Conclusion

ACE polymorphisms were shown to play a major role in individual susceptibility to develop CAD. There is also a clear interaction between RAS predisposing genes and some biochemical/environmental risk factors in CAD onset, demonstrating a significant enhancement of classical markers particularly by ACE I/D and ACE11860.

Association between the insertion/deletion polymorphism of the angiotensin-converting enzyme gene and erectile dysfunction in patients with metabolic syndrome

This study was designed to investigate whether angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism is associated with erectile dysfunction (ED) in Russian men with metabolic syndrome (MS). A total of 331 men with MS were studied. All patients underwent complex evaluation including the International Index of Erectile Function (IIEF) questionnaire. The ACE I/D polymorphism was determined by polymerase chain reaction. Overall, 182 men (55.0%) had ED according to the IIEF erectile function domain score. In the ED group, the prevalence of DD genotype was found to be significantly higher compared to the non-ED group (P<0.001). In both groups, patients with DD genotype were significantly younger than patients with other genotypes (P<0.001). In addition, in the ED group, the disease affected patients with DD genotype at a significantly younger age (P<0.001). Obtained results give evidence to support the finding that the D allele is a risk factor for the micro- and macrovascular diseases.

Relationship between angiotensin-converting enzyme gene polymorphism and severity of aortic valve calcification

OBJECTIVE

To investigate the role of angiotensin-converting enzyme (ACE) gene polymorphism in patients with degenerative aortic valve calcification (AVC).

PATIENTS AND METHODS

Our study consisted of 305 Turkish patients of European descent (139 male, 166 female; mean plus or minus age, 68 plus or minus 9 years) referred to our echocardiography laboratory for aortic valve evaluation between June 2, 2003, and April 29, 2005. The severity of AVC was graded from 1 to 6 by echocardiography. We used polymerase chain reaction to determine ACE gene polymorphism.

RESULTS

The ACE insertion/deletion genotype distributions for the study population were in Hardy-Weinberg equilibrium (chi square equals 3.5, P equals .18). The study population was divided into 3 groups based on the severity of AVC: those with grade 1 calcification were in group 1, those with grades 2 to 4 in group 2, and those with grades 5 to 6 in group 3. Group 1 patients were significantly younger, less likely to have hypertension and diabetes, and had higher high-density lipoprotein cholesterol levels. The genotype frequencies were significantly different among groups, with the insertion/insertion genotype being less prevalent in group 3 patients. In multivariate analysis, independent predictors of severe AVC were hypertension (odds ratio [OR], 5.6; 95% confidence interval [CI], 2.8 to 11.0; P less than .001), low high-density lipoprotein cholesterol (OR, 2.7; 95 percent CI, 1.5 to 4.9; P equals .001), and the deletion/deletion and insertion/deletion vs insertion/insertion genotype (OR, 3.2; 95 percent CI, 1.5 to 7.2; P equals .004).

CONCLUSION

These results suggest that ACE gene polymorphism may be associated with severe AVC.

Biomarkers of obesity and subsequent cardiovascular events

Obesity is a major risk factor for cardiovascular diseases, but the mechanisms for increased cardiovascular risk in obesity are still unclear. Inflammation and increased oxidative stress are two potential mechanisms proposed to play a major role in the morbidity associated with obesity. Studies that investigate these mechanisms rely on biomarkers, but validated biomarkers for obesity-related cardiovascular outcomes are lacking. By finding optimal biomarkers, diagnostic criteria for cardiovascular diseases can be refined in the obese beyond "traditional" risk factors to identify early pathologic processes. The objective of this review is to identify potential early biomarkers resulting from obesity and associated with cardiovascular disease. Studies were initially identified through the search engine PubMed by using the keywords "obesity" and "biomarker." Subsequently, combinations of the keywords "obesity," "biomarker," "cardiovascular risk," "adipose tissue," "adipokine," "adipocytokine," and "oxidative stress" were used. The SOURCE database and Online Mendelian Inheritance in Man (OMIM) were used to obtain more information on the biomarkers. Results of the searches yielded a large number of potential biomarkers that occur in obesity and which either correlate with traditional cardiovascular risk factors or predict subsequent cardiovascular events. Several biomarkers are promising regarding their biologic properties, but they require further validation in humans.

Influence of angiotensin converting enzyme insertion/deletion polymorphism on long-term total graft occlusion after coronary artery bypass surgery

BACKGROUND

The renin-angiotensin system has a very important role in coronary thrombosis and restenosis. Plasma angiotensin converting enzyme (ACE) activity is associated with an insertion/deletion polymorphism in the gene coding for ACE. It is known that there is a strong correlation between ACE DD and atherosclerosis. However, little has been documented about its role in venous graft failure. The objective of this study was to investigate the relationships among the ACE gen polymorphism and long-term vein graft occlusion.

METHODS

The study population consisted of 87 consecutive white patients with symptomatic coronary artery disease in the previous month, who had had aorto-coronary bypass surgery (ACBS) more than 5 years back and who underwent coronary angiography for diagnostic purposes. On the same day of angiography, 10 mL whole blood was taken for ACE gene insertion/deletion (I/D) polymorphism.

RESULTS

Mean age of the patients was 64.4 +/- 8.6 years, and 71 (82%) of the patients were men. The average ACBS time was 7.9 +/- 1.9 years. The ACE genotype was II in 15 patients (17.2%), ID in 47 patients (54.0%), and DD in 25 patients (28.7%). Thus, D allele frequency was .82. There was no significant difference between the cases with regard to age, body mass index, blood pressure status, plasma glucose level, plasma lipid profile, smoking status, average of ACBS time or family history of coronary heart disease. In ACE II group 5 patients had total venous graft occlusion, in ACE ID group 27 patients had total occlusion and in ACE DD group 20 patients had at least one graft total occlusion. The frequency of the venous graft occlusion about total venous grafts is 36% in the ACE II group, 49% in the ACE ID group, and 80% in the ACE DD group (P = .01).

CONCLUSION

The ACE I/D gene polymorphism is associated with long-term survival of venous conduit. The ACE DD genotype or D allele influences the angiographic outcome of patients post-ACBS. These data suggest that routine determination of the ACE genotype may help identify patients who are at higher risk of venous graft failure after ACBS.

Angiotensin-converting enzyme gene polymorphism and allele frequencies in the lebanese population: prevalence and review of the literature

We studied the distribution of the D/D, I/D, and I/I genotypes of the angiotensin-converting enzyme (ACE) in a sample of healthy Lebanese individuals to assess their prevalence and compare them with other populations. ACE genotypes were determined using the Cardiovascular Disease (CVD) StripAssay, which is based on a Polymerase Chain Reaction-Reverse hybridization technique. DNA from 133 unrelated healthy donors from our HLA-bank was used. The prevalence of D/D, I/D, and I/I genotypes was found to be 39.1, 45.1, and 15.8% respectively, with D and I allelic frequency of 61.7 and 38.3%, respectively. The sampled Lebanese population showed ACE genotypic distributions similar to Caucasians; however, with tendency towards harboring high D allele frequency together with a low I allele frequency just like the Spanish population. This first report from Lebanon will serve as a baseline statistical data for future investigations of the prevalence of ACE genotypes in association with various clinical entities notably cardiovascular diseases. The medical literature was also reviewed in this context.

The kallikrein-kinin system: current and future pharmacological targets

The kallikrein-kinin system is an endogenous metabolic cascade, triggering of which results in the release of vasoactive kinins (bradykinin-related peptides). This complex system includes the precursors of kinins known as kininogens and mainly tissue and plasma kallikreins. The pharmacologically active kinins, which are often considered as either proinflammatory or cardioprotective, are implicated in many physiological and pathological processes. The interest of the various components of this multi-protein system is explained in part by the multiplicity of its pharmacological activities, mediated not only by kinins and their receptors, but also by their precursors and their activators and the metallopeptidases and the antiproteases that limit their activities. The regulation of this system by serpins and the wide distribution of the different constituents add to the complexity of this system, as well as its multiple relationships with other important metabolic pathways such as the renin-angiotensin, coagulation, or complement pathways. The purpose of this review is to summarize the main properties of this kallikrein-kinin system and to address the multiple pharmacological interventions that modulate the functions of this system, restraining its proinflammatory effects or potentiating its cardiovascular properties.

Angiotensin converting enzyme gene polymorphism and cardiovascular morbidity and mortality: the Rotterdam Study

BACKGROUND

Findings on the association between the insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene and cardiovascular morbidity and mortality have been inconsistent. Considering the possible interaction between this polymorphism and smoking, we evaluated the association between ACE I/D polymorphism and myocardial infarction (MI), mortality due to coronary heart disease (CHD), and cardiovascular disease (CVD).

METHODS

The study was performed within the Rotterdam Study, a population based cohort study. The ACE I/D polymorphism was determined for 6714 participants and smoking status recorded at baseline. Fatal and non-fatal MIs and mortality events were regularly recorded. Cox proportional hazard analysis was performed separately for current smokers and non-smokers. We used age as the follow up time, presenting age specific survivals.

RESULTS

During follow up, 248 MIs and 301 and 482 deaths, respectively, due to CHD and CVD occurred. There were no significant differences between the genotypes as regards MI incidence. Among smokers, there was an increased risk of CHD and CVD mortality in carriers of the DD genotype compared to the II genotype, which diminished at later ages (p<0.01 for gene-age interaction). Subgroup analysis in a younger and older group (based on the median age of 68.2 years) showed a significantly increased risk of CVD mortality in the younger group (hazard ratio = 5.19; 95% confidence interval: 1.15 to 23.42).

CONCLUSIONS

This study showed that the ACE I/D polymorphism is not a strong risk factor for MI but its interaction with smoking might play a role in cardiovascular mortality especially at younger ages.

Haplotypes of the beta-2 adrenergic receptor associate with high diastolic blood pressure in the Caerphilly prospective study

OBJECTIVES

Current evidence demonstrates that both genetic and environmental factors influence blood pressure. The sympathetic nervous system is a key player in blood pressure control and functional genetic variants of the beta-2 adrenergic receptor (B2AR) have been identified and implicated in the pathogenesis of hypertension. The present study aimed to determine the effects of common haplotypes of the B2AR gene upon blood pressure in the Caerphilly Prospective Study.

DESIGN

Two thousand five hundred and twelve men (aged 45-59 years) participated in the study. We selected individuals in the upper (n = 347) and lower (n = 279) quintiles of the diastolic blood pressure distribution fixed at two time points [phase 2 (1984-88) or phase 3 (1989-93)] as cases and controls.

METHODS

We analysed two functional polymorphisms (Arg16Gly and Gln27Glu) of B2AR and their haplotypes.

RESULTS

We found a higher risk of hypertension in individuals homozygous for the Gln27 compared to those individuals homozygous for Glu27 [odds ratio (OR) = 1.94; 95% confidence interval (CI) = 1.34-2.81; P = 0.001]. Three haplotypes (Gly16Gln27, Gly16Glu27 and Arg16Gln27) were present in both quintile groups. Logistic regression analysis showed that haplotypes with a Gln27 allele (Gly16Gln27 and Arg16Gln27) conferred a significantly higher risk for hypertension than the Gly16Glu27 haplotype (OR = 1.55; 95% CI = 1.11-2.17, OR = 1.37; 95% CI = 1.04-1.81; P = 0.009 and P = 0.027, respectively). However, there was no evidence to support a statistically significant difference in odds ratios for the Gly16Gln27 and Arg16Gln27 haplotypes (P = 0.477), suggesting that it is the Gln27 allele alone, rather than any haplotype, which best explains the association.

CONCLUSIONS

In a prospectively studied Caucasian male cohort, high diastolic blood pressure was associated with B2AR haplotypes containing the pro-downregulatory Gln27 variant.

Increased deformability of red blood cells is associated with a deletion polymorphism of the angiotensin-converting enzyme gene

Angiotensin-converting enzyme (ACE) plays important roles in the renin-angiotensin system. ACE converts angiotensin I to angiotensin II and also inactivates bradykinin, thereby modulating the vascular tone. A polymorphism of the ACE gene, located on chromosome 17, has been found in intron 16, and is characterized by the presence (insertion [I]) or absence (deletion [D]) of a 287-base-pair Alu repeat. Individuals with the D allele of the ACE gene have higher ACE levels and are at higher risk of cardiovascular events. We aimed to investigate the possible relationship between the I/D polymorphism of the ACE gene and hemorheological parameters, including red blood cell (RBC) deformability. The study was performed on 28 healthy young volunteers (13 women and 15 men, mean age 24 +/- 2). The prevalence of the I and D alleles was 30.4% and 69.6%, respectively. The I/I genotype (II) was found in 21.4%, I/D genotype (ID) in 17.9%, and D/D genotype (DD) in 60.7% of the subjects tested. No significant relationship between ACE I/D polymorphism and RBC aggregation or whole blood and plasma viscosity was observed. In contrast, RBC deformability was significantly increased in the subjects with the DD genotype compared with the II (p < 0.05) or the ID (p < 0.01) genotype, and in the subjects with the D allele compared with the I allele (p < 0.01). We suggest that RBC deformability of individuals with the D allele, who have higher risk for cardiovascular pathologies, may have been increased by a compensatory mechanism.

The association between angiotensin-converting enzyme gene polymorphism and coronary calcification. The Rotterdam Coronary Calcification Study

BACKGROUND

An insertion/deletion (I/D) polymorphism in the gene encoding angiotensin-converting enzyme (ACE) has been associated with serum ACE levels. The association between the ACE I/D polymorphism and coronary heart disease is unclear. Electron-beam-computed tomography (EBT) is a technique to non-invasively quantify the amount of coronary calcification. We investigated the association between the ACE I/D polymorphism and coronary calcification.

METHODS AND RESULTS

The Rotterdam Coronary Calcification Study is a population-based study in subjects aged 55 years and over. EBT scanning was performed in 2013 participants. Coronary calcification was quantified according to the Agatston score. The ACE I/D polymorphism was available for 1976 subjects. Geometric mean calcium scores in men with the II, ID and DD genotype were 167, 207 and 219, respectively. However, the difference in calcium score (p=0.19 for ID versus II; p=0.15 for DD versus II) and the trend (ptrend=0.17) were not significant. Calcium scores in women with the II, ID and DD genotype were 44, 42 and 36, respectively. There were no significant differences in calcium score (p=0.78 for ID versus II; p=0.29 for DD versus II), neither was the trend (ptrend=0.27). After we stratified on cardiovascular risk factors, no associations were present.

CONCLUSION

The present study failed to show an association between the ACE I/D polymorphism and coronary calcification in the general population. Also, no significant associations were present between the ACE I/D polymorphism and coronary calcification in strata of cardiovascular risk factors.

The relationship between ACE insertion/deletion polymorphism and coronary artery disease with or without myocardial infarction

OBJECTIVES

Presence of the D allele or homozygosity for the deletion (D) allele of the angiotensicen-converting enzyme (ACE) insertion/deletion (I/D) polymorphism has been discussed as potent risk factor for coronary artery disease (CAD) and myocardial infarction (MI). The D allele is associated with higher levels of circulating ACE and therefore may predispose one to cardiovascular damage.

DESIGN AND METHODS

The study presented here was performed to investigate the association between the ACE genotype and ACE levels. The study group was comprised of 118 angiographically verified CAD patients. 65 patients were MI (+) and 53 patients were MI (-) in this group. A total of 70 healthy individuals were taken as controls. Genomic DNA of 188 subjects was extracted from whole blood. The polymerase chain reaction was used for ACE genotyping, and ACE levels were measured by ELISA.

RESULTS

The D allele was found to be significantly more frequent in patients with MI (+) compared with controls (P = 0.024). ACE levels were significantly higher in both MI (-) and MI (+) groups with CAD patients than in controls (P < 0.005). Plasma ACE level was higher in all three groups in the DD genotype compared to II genotype. In groups I and III, this was statistically significant (P < 0.0001, P < 0.01).

CONCLUSIONS

It was shown that the I/D polymorphism in the gene for ACE is a genetic risk factor for CAD patients who have a history of MI. ACE insertion/deletion gene polymorphism is also associated with plasma ACE levels in CAD patients with a history of MI.

Deletion polymorphism in the gene for angiotensin-converting enzyme is associated with essential hypertension in men born during the Pacific War

Age is a strong risk factor for hypertension in relation to vascular aging. Additional etiological factors include: lifestyle, genetic factors, and their interactions. The aim of this study is to examine whether an insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene is associated with essential hypertension in Korean born during the Pacific War. A total of 13,914 healthy subjects (8261 men, 5653 women) aged 20-79 years were examined. Subjects with abnormal renal, thyroid dysfunction, or electrolyte levels were excluded. Logistic regression analysis showed increased risk (OR=1.15; 95% CI, 1.01-1.31) in men, but not in women (OR, 1.06; 95% CI, 0.89-1.26). However, after adjustment for age, obesity, cholesterol, alcohol consumption, and diabetes mellitus, increased risk in men was not significant (OR, 1.13; 95% CI, 0.98-1.42). Analyzed according to birth-year, DD genotype showed increased risk for hypertension in only a subgroup of men (adjusted OR, 1.56; 95% CI, 1.16-2.09; p = 0.001), born during the Pacific War (1941-1945 year). Findings suggest that the ACE DD genotype plays a role in the pathogenesis of essential hypertension, in conjunction with adverse environmental conditions in early life, with sex-related difference.

Angiotensin-converting enzyme I/D polymorphism in Behçet's disease

OBJECTIVE

To investigate a potential relationship between I/D polymorphism within intron 16 of the angiotensin-converting enzyme (ACE) gene located on human chromosome 17 and Behçet's disease.

MATERIALS AND METHODS

Genomic DNA was obtained from 35 Turkish patients diagnosed with Behçet's disease according to the International Study Group criteria and 150 healthy individuals. Polymerase chain reaction was used to detect the presence of I and D (insertion and deletion) alleles in intron 16 of the ACE gene in these DNA samples.

RESULTS

We found differences in ACE I/D polymorphism between Behçet's disease and healthy controls (chi2=4.61, d.f.=1, p=0.044). In Behçet's disease patients, the D allele frequency was 84.3% and I allele frequency 15.7%.

CONCLUSION

An association between Behçet's disease and ACE polymorphism may provide a useful basis for future molecular studies and therapeutic approaches in this complex disease.

The Role of Angiotensin Converting Enzyme Genotype in Coronary Artery Ectasia

Coronary artery ectasia (CAE) is characterised by irregular, diffuse, saccular, or fusiform dilatation of the coronary arteries. Although the underlying mechanisms are not fully understood, CAE is considered to be an original form of vascular remodelling in response to atherosclerosis. However, it is not clear why some patients develop CAE while most do not. Experimental data suggest that activation of the renin angiotensin system may lead to an increased inflammatory response in the vessel wall or to an activation of matrix metalloproteinases. In addition, an insertion/deletion (ID) polymorphism of angiotensin converting enzyme (ACE) has been associated with coronary vascular tone and the development of aneurysms. Accordingly, we hypothesised that the gene polymorphism of ACE may be a potential factor influencing the genesis of CAE. We retrospectively evaluated 112 patients who underwent coronary angiography. ACE ID genotype was determined in two groups of patients. Group 1 consisted of 56 patients who were found to have CAE. Group 2 consisted of 56 patients with significant coronary artery disease (CAD) (> 50% stenosis in any of the major epicardial coronary arteries or their branches) but without any evidence of coronary ectasia. Polymerase Chain Reaction (PCR) was used to detect ACE genotype. The ratio of DD genotype was found to be greater in group 1 than group in 2 (39% versus 18%, respectively, P < 0.05). When assessed according to the presence of the I allele, it was greater was greater in group 2 than in group 1 (82.1% versus 60.7%, respectively, P < 0.05). The results indicate that an ACE DD genotype may be a risk factor for CAE.

The relation between obesity, abdominal fat deposit and the angiotensin-converting enzyme gene I/D polymorphism and its association with coronary heart disease

OBJECTIVE

To analyse the relation between overweight, obesity and fat distribution with I/D polymorphism of the angiotensin-converting enzyme (ACE) gene and its association with coronary heart disease (CHD).

DESIGN

Cross-sectional, case-control study.

SUBJECTS

A total of 185 cases (141 males) who had suffered at least one episode of CHD and 182 controls (127 males).

MEASUREMENTS

Body mass index, waist circumference, blood pressure, plasma total cholesterol, triglycerides, HDL cholesterol and fasting glucose were measured with standard methods, genotyping the I/D polymorphism of ACE gene.

RESULTS

Obesity and abdominal fat deposit are associated with CHD in women, but not independently. We have found an association between obesity and abdominal fat deposit with the ACE gene I/D polymorphism in subjects with CHD. Subjects with CHD and DD or ID genotypes have significantly higher prevalence of obesity and abdominal fat deposit and higher values of weight and waist circumference. In addition, the DD and ID genotypes increased crude OR of obesity. The DD and ID genotypes of the ACE gene I/D polymorphism and BMI are independently associated with CHD.

CONCLUSION

There is a relation between the type and grade of obesity with the genotypes of the ACE gene I/D polymorphism in subjects with CHD.

An application of conditional logistic regression and multifactor dimensionality reduction for detecting gene-gene interactions on risk of myocardial infarction: the importance of model validation

Background

To examine interactions among the angiotensin converting enzyme (ACE) insertion/deletion, plasminogen activator inhibitor-1 (PAI-1) 4G/5G, and tissue plasminogen activator (t-PA) insertion/deletion gene polymorphisms on risk of myocardial infarction using data from 343 matched case-control pairs from the Physicians Health Study. We examined the data using both conditional logistic regression and the multifactor dimensionality reduction (MDR) method. One advantage of the MDR method is that it provides an internal prediction error for validation. We summarize our use of this internal prediction error for model validation.

Results

The overall results for the two methods were consistent, with both suggesting an interaction between the ACE I/D and PAI-1 4G/5G polymorphisms. However, using ten-fold cross validation, the 46% prediction error for the final MDR model was not significantly lower than that expected by chance.

Conclusions

The significant interaction initially observed does not validate and may represent a type I error. As data-driven analytic methods continue to be developed and used to examine complex genetic interactions, it will become increasingly important to stress model validation in order to ensure that significant effects represent true relationships rather than chance findings.

Does angiotensin-converting enzyme gene polymorphism affect blood pressure? Findings after 6 years of follow-up in healthy subjects

BACKGROUND

There has been an increase in research into the association between angiotensin-converting enzyme (ACE) gene deletion polymorphism and cardiovascular disease, with conflicting results. The present prospective long-term study was conducted to evaluate whether the DD genotype could also be associated with a higher prevalence of hypertension in healthy subjects, over 6 years of follow-up.

METHODS

POPULATION

684 healthy volunteers (aged, 25-55 years): normotensive and free of cardiovascular diseases, with acceptable echocardiographic window. All subjects had to have a normal electrocardiogram (ECG) and echocardiogram (ECHO) at entry.

STUDY PROTOCOL

All subjects underwent a complete physical examination, 12-lead ECG and ECHO, and venous blood samples were drawn for DNA analysis and cholesterol. All subjects had a clinical evaluation each year for the 6 year duration of the study.

RESULTS

All 684 subjects completed 6 years of follow-up. We identified three genetically distinct groups. The ACE-DD group (n=225, 80F/145M, mean age 43.4+/-7.6 years) had 42 hypertensive subjects (18.3%), 5 heart failure (HF) subjects and 6 subjects with acute coronary syndromes (ACS). There was no association between family history, smoking habit, hypercholesterolemia and events. The ACE-ID group (n=335, 116F/219M, mean age 43.6+/-7 years) had 16 hypertensive subjects (4.7%) and 3 subjects with ACS. The ACE-II group (n=124, 45F/79M, mean age 42.5+/-6.9 years) had 2 hypertensive subjects (1.6%) and 1 HF subject. The incidence of hypertension and cardiovascular events was significantly higher in the ACE-DD group (53 cases, 23%) than in the ACE-ID and ACE-II groups (20 and 3 cases, 5.9 and 2.4%, respectively), P=0.0001. The higher incidence of hypertension was observed in the older age groups (36-45 and 46-55 years) with ACE-DD and ACE-ID genotypes.

CONCLUSION

Our data suggest that ACE-DD polymorphism is associated with a higher incidence of hypertension in baseline healthy subjects, irrespective of other risk factors. The higher incidence of hypertension was apparent predominantly in the older age groups.

Genetic determinants of arterial calcification associated with atherosclerosis

Increasing research interest has focused on arterial calcification in the setting of atherosclerosis. Many features of atherosclerosis-related calcification provide useful clinical information. For example, calcium mineral deposits frequently form in atherosclerotic plaque, and intimal arterial calcification can be used as a surrogate marker for atherosclerosis; also, calcium deposits are readily and noninvasively quantified, which is useful because greater amounts of coronary calcification predict a higher risk of myocardial infarction and death. Several mechanisms leading to calcification associated with atherosclerosis have been proposed; however, no direct testing of proposed mechanisms has yet been reported. Studies in genetically altered animals and in humans have shed light on potential genetic determinants, which in turn could form the basis for a more comprehensive understanding of the factors affecting calcification within plaque and the associated pathobiologic implications. We review proposed molecular and cellular mechanisms of atherosclerosis-associated arterial calcification, summarize genetic influences, and suggest areas in which further investigation is needed. Understanding the molecular and genetic determinants of specific structural plaque components such as calcification can provide a solid foundation for the development of novel therapeutic approaches to favorably alter plaque structure and minimize vulnerability to arterial rupture.

Angiotensin Converting Enzyme Genotype Influences the Response to the Angiotensin II Receptor Antagonist Losartan in Patients with Hypertension

To examine whether the response to the angiotensin II receptor antagonist losartan varies depending on the angiotensin converting enzyme (ACE) genotype, we prospectively studied the effect of losartan in 42 hypertensive patients (20 men, 22 women; mean age: 60.4 years). After a 4-week observation period, losartan was administered at 50 mg/day and blood pressure was measured every 2 to 4 weeks for 12 weeks. Among the 42 patients, 19, 11, and 12, respectively, had the II, ID, and DD ACE genotypes. The baseline plasma ACE activity in patients with the ID or DD genotype was significantly higher than that in patients with the II genotype (13.8 +/- 4.2 vs. 9.6 +/- 2.3 IU/l; p = 0.0002). However, age, gender, baseline systolic and diastolic blood pressure (SBP/DBP), and body mass index (BMI) were not different among the groups. After 12 weeks of treatment with losartan alone, DBP in the ID+DD group was significantly higher than that in the II group (85.0 +/- 9.0 vs. 77.8 +/- 9.6 mmHg, p = 0.018), while the percent reduction in DBP in the ID+DD group was significantly smaller than that in the II group (7.9 +/- 8.8 vs. 14.3 +/- 10.1%, p = 0.035). Multiple regression analysis showed that the significant predictors of the DBP at 12 weeks were age (p = 0.030), ACE genotype (p = 0.029) and baseline DBP (p = 0.0001). The ACE genotype may be a determinant of the response to losartan in hypertensive patients.

Angiotensin-converting enzyme DD genotype in patients with primary pulmonary hypertension: increased frequency and association with preserved haemodynamics

HYPOTHESIS/INTRODUCTION: A polymorphic marker within the angiotensin- converting enzyme (ACE) gene has been associated with circulating and tissue ACE activity and with a variety of forms of cardiovascular disease. Since angiotensin II (Ang II) causes pulmonary vasoconstriction and vascular and myocardial remodelling, we postulated a role for the renin-angiotensin system and the ACE DD genotype in the pathophysiology of primary pulmonary hypertension (PPH) and in the right ventricular response to pressure overload in these patients.

METHODS AND RESULTS

The incidence of the ACE DD genotype was evaluated in 60 patients with severe PPH compared with two normal control populations, a group of healthy population-based controls (n=158) and subjects found suitable for cardiac organ donation (n=79). Genomic DNA extracted from peripheral leukocytes was amplified using the polymerase chain reaction to detect polymorphic markers. Haemodynamics were determined by right heart catheterisation in a subset of the PPH patients. The frequency of the ACE DD genotype was 45% in the patients with PPH, compared with 24% in the organ donors, and 28% in population-based healthy controls (p=0.01 for chi-square test). Of the 32 PPH patients with baseline haemodynamics, 12 exhibited the ACE DD genotype and 20 were non-DD. While the mean pulmonary artery pressure and the duration of symptoms attributable to pulmonary hypertension was not different between the DD and non-DD groups, cardiac output was significantly lower (3.29+0.27 vs. 5.07+0.37 L/minute, p=0.002) and the mean right atrial pressure tended to be higher (8.85+1.29 vs. 4.92+1.27 mmHg, p=0.08) in the non-DD group. The reduction in cardiac output seen in the non-DD group was not due to a difference in heart rate, but to a significant reduction in stroke volume, consistent with a decreased contractile state. In addition, non-DD patients exhibited a significantly worse functional capacity (NYHA Class 3.14+0.12 vs. 2.40+0.28, p=0.02).

CONCLUSIONS

1) The ACE DD genotype is significantly increased in patients with severe PPH compared with normal controls, suggesting that certain individuals may be genetically predisposed to developing pulmonary hypertension. 2) The ACE DD genotype is associated with preserved right ventricular function in PPH patients, supporting a compensatory myocardial or inotropic role for Ang II in the pressure overloaded right ventricle.

Distributions of ACE and APOE polymorphisms and their relations with dementia status in Korean centenarians

BACKGROUND

Genetic polymorphisms of angiotensin-converting enzyme (ACE) and apolipoprotein E (APOE) have been reported to be associated with human longevity and dementia in the elderly. However, whether such putative longevity genes exert the same effects on different ethnic groups living in different environments is not well known.

METHODS

We investigated the distributions of the ACE and APOE genotypes and their relations with dementia status in Korean centenarians by cross-sectional study. A total of 103 centenarians (13 men and 90 women, mean age 102.4 +/- 2.6 years) were included in this study. The allele frequencies of the genes were compared with those of two control groups: 7232 apparently healthy adults (4100 men and 3132 women) of mean age 48.5 +/- 9.6 years for the ACE genotyping, and 6435 adults (5008 men and 1427 women) of mean age 50.7 +/- 7.9 years for the APOE genotyping. The dementia status of the centenarians was assessed by clinical psychologist using the Clinical Dementia Rating (CDR) score.

RESULTS

The frequencies of genotypes and alleles of the ACE and APOE genes of the centenarians were not significantly different from those of the control groups. There was a lack of association between presence of the D allele on the ACE gene and dementia status. However, the frequency of the epsilon4 allele of the APOE gene was significantly higher in centenarians with dementia than in centenarians without definitive dementia (9.1% versus 1.5%, p <.05).

CONCLUSIONS

These results suggest that neither the ACE nor the APOE gene is significantly associated with longevity in the Korean population, but that the APOE epsilon4 allele is still related with dementia even at age 100 and older.

Mitochondrial 5178A/C genotype is associated with acute myocardial infarction

A single nucleotide polymorphism of mitochondrial 5178A/C, causing a Met to Leu replacement within the NADH dehydrogenase subunit, is reported to be associated with longevity. The purpose of the present study was to assess the contribution of mitochondrial polymorphisms, particularly the 5178A/C genotype, to the susceptibility to acute myocardial infarction (AMI) in a Japanese study population. There were 4 groups: 150 patients with AMI, 150 with essential hypertension, 100 with diabetes mellitus, and 150 subjects matched for age and sex who served as the control group. Mitochondrial 5178A/C was detected by the polymerase chain reaction restriction fragment length polymorphism method. The allelic frequency of 5178C was significantly higher in the AMI group than in the control group, and this difference was more marked in younger patients. There were differences in allelic frequencies among the essential hypertension group, diabetes mellitus group and control group, but a higher frequency of the C allele was seen in the AMI group compared with the essential hypertension and diabetes mellitus groups. This particular polymorphism was found to be associated with development of AMI, especially in younger patients and constitutes a new risk factor for AMI.

Angiotensin I-converting enzyme insertion/deletion polymorphism and cardiac mortality and morbidity after coronary artery bypass graft surgery

STUDY OBJECTIVES

This study was designed to evaluate whether the insertion (I)/deletion (D) polymorphism of the angiotensin I-converting enzyme (ACE) gene is associated with mortality and cardiac morbidity after coronary artery bypass graft surgery (CABG).

METHODS AND RESULTS

The ACE I/D genotype was determined in 249 consecutive patients who underwent CABG. Follow-up information (after 2 years) was obtained in 247 patients (99.2%). The primary end point was total mortality; the secondary end point was mortality from cardiac reasons, or the need for myocardial revascularization (coronary angioplasty or recurrent CABG) during follow-up. At follow-up, total mortality was 9.7% (all patients). None of the 51 patients with the ACE II genotype, 14 of 125 patients with the ACE ID genotype (11.2%), and 10 of 71 with the ACE DD genotype (14.1%) died during follow-up (p < 0.05). The ACE DD genotype, older age, diabetes mellitus, decreased left ventricular ejection fraction, and lack of internal mammary artery graft were independently related to an increased mortality after CABG. The incidence of the secondary end point was 14.5% (all patients): ACE II, 5.8%; ACE ID, 9.4%; ACE DD, 30.3% (p < 0.05). The ACE DD genotype and the presence of a left main coronary artery stenosis >or= 50% were independent predictors for the secondary end point.

CONCLUSION

The ACE DD genotype is associated with increased midterm mortality and cardiac morbidity after CABG.

Coronary artery disease and dyslipidemia within Europe: genetic variants in lipid transport gene loci in German subjects with premature coronary artery disease

Fifteen polymorphisms in six lipid transport genes were studied in a German population for relationships with dyslipidemia and coronary artery disease (CAD), to investigate a possible genetic basis for the marked differences in mortality rates from coronary heart disease within Europe. In other populations these polymorphisms have all been associated with CAD or with phenotypes known to predispose to CAD. The apoAI PstI polymorphism (P<0.005) and the lipoprotein lipase Ser(447)-Ter mutation (P<0.005) were associated with plasma triglyceride concentrations. Additionally, the apoAI PstI polymorphism (P<0.05), the apoB XbaI polymorphism (P<0.05) and apoE phenotypes (P<0.05) were associated with plasma cholesterol concentrations. However, none of the allele frequencies of the polymorphisms studied were related to the presence, or absence, of coronary artery disease. Associations between five polymorphisms representing four lipid transport gene loci and dyslipidemia were demonstrated in this German population. It is possible that predisposition to dyslipidemia in Germany involves a particular selection of polymorphic loci, which are different from those identified in other European countries.

Is angiotensin I-converting enzyme a "master" disease gene?

Clustering of diseases has been appreciated by health insurers and epidemiologists for some time. Co-morbidity suggests shared pathways of disease. It is by now well agreed that common diseases have a strong genetic component. Here we present evidence that the angiotensin I-converting enzyme (ACE) deletion/deletion (D/D) genotype is associated with a large number of common adult diseases, including cardiovascular disease, cancer, and psychiatric disease. Since the ACE D/D genotype has been shown to be associated with increased levels of tissue ACE expression at the protein level, these data suggest that overactivity of ACE may be involved in the pathogenesis of common diseases, as well as the utility of effective ACE inhibition in their treatment and, perhaps, prevention.

Angiotensin converting enzyme DD genotype affects the changes of plasma plasminogen activator inhibitor-1 activity after primary percutaneous transluminal coronary angioplasty in acute myocardial infarction patients

Angiotensin converting enzyme (ACE) DD genotype, and plasminogen activator inhibitor (PAI-1) 4G/4G genotype have been reported to affect PAI-1 activity in control subjects and atherosclerotic patients, but no data are available on the influence of angiotensin II type 1 receptor (AT1R) A1166C polymorphism on the inhibitor levels. The degree of fibrinolytic activation after percutaneous transluminal coronary angioplasty (PTCA) has been found to affect the risk of restenosis. The aim of this study was to investigate the possible influence of ACE I/D, AT1R A1166C, and PAI-1 4G/5G polymorphisms on the changes of PAI-1 activity after primary successful percutaneous transluminal angioplasty. In 29 consecutive acute myocardial infarction patients, undergoing primary successful angioplasty, genotyping of ACE I/D, AT1R A1166C, and PAI-1 4G/5G polymorphisms was performed by polymerase chain reaction and restriction fragment length polymorphism analysis, and PAI-1 plasma activity (chromogenic method) was assessed before and after angioplasty. Following angioplasty, PAI-1 activity increased in 10 of 29 patients and decreased or remained unchanged in 19 of 29. ACE DD genotype was significantly (P = 0.04) associated with an increase of PAI-1 activity post angioplasty (OR DD/ID+II = 6.5, CI 95% 4.83-8.22). Whereas no effect of PAI-1 4G/5G and AT1R A1166C polymorphisms on PAI-1 response to angioplasty was demonstrated, these data suggest that renin-angiotensin system genes are involved in the regulation of the fibrinolytic response to balloon injury, possibly affecting angiotensin converting enzyme activity. This interaction between the renin-angiotensin system and hemostasis may be a mechanism by which ACE DD genotype affects the risk of restenosis after percutaneous transluminal angioplasty.

Interaction between apolipoprotein-E and angiotensin-converting enzyme genotype in Alzheimer's disease

Both apolipoprotein-E (apo-E) epsilon 4 allele and angiotensin-converting enzyme (ACE) deletion (D) polymorphism have been associated with a high risk for coronary heart disease. Increased frequency of the epsilon 4 allele has also been reported in patients with late-onset of familial and sporadic Alzheimer's disease (AD). The primary aim of this study is to examine the possible relationship between the ACE gene polymorphism and AD. The second aim of this study is to explore the relation of the ACE and apo-E genotypes with AD. Polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), and agarose gel electrophoresis techniques were used to determine the apo-E and ACE genotypes. The frequencies of ACE D and ACE insertion (I) allele among AD patients and controls were 55.7 percent versus 44.2 percent and 51.7 versus 48.2 percent, respectively. Apo-E allele frequencies in the AD group for epsilon 2, epsilon 3 and epsilon 4 were, 1.7 percent, 96.5 percent, and 1.7 percent, respectively. The apo-E allele frequencies of healthy groups for epsilon 2, epsilon 3 and epsilon 4 were 1 percent, 56 percent, and 1.7 percent, respectively. In conclusion ACE D and apo epsilon 4 allele were found to be more frequent in patients with Alzheimer's disease than in the control group.