Genetic basis of left ventricular remodeling after myocardial infarction

Role of Angiotensin-Converting Enzyme (ACE) gene polymorphism and ACE activity in predicting outcome after acute myocardial infarction

•

The role of ACE gene polymorphism and its influence on ischemic heart disease and acute coronary syndrome are studied in last so many years without any concrete conclusion.

•

In this study we investigated role of ACE gene polymorphism and Ace activity in large number of study population.

•

The ACE (I/D) polymorphism showed no association with development of acute STEMI. Neither ACE I/D polymorphism nor ACE activity predicted in-hospital mortality in patients admitted with acute STEMI.

•

Hence knowledge of ACE polymorphism and Ace activity is not useful in predicting STEMI or mortality after STEMI.

Background

The Ace polymorphism had shown association with ACE activity, premature atherosclerosis, myocardial infarction, LV dysfunction, LV remodelling, severity and extent of CAD and mortality after MI. Though ACE I/D polymorphism has been reported to be associated with various cardiovascular diseases it remained a controversial risk factor and studies have presented conflicting results. This study was designed to determine the association between ACE) gene insertion/deletion (I/D) polymorphism, ACE activity and acute STEMI in Indian population and to determine its influence on outcome after acute MI.

Materials and methods

We investigated 934 patients diagnosed with acute STEMI who underwent thrombolysis. ACE I/D polymorphism was detected by polymerase chain reaction and ACE activity was measured in 615 patients.

Results

The prevalence of DD, ID, and II genotypes in our study group were 41.97%, 34.36%, and 23.66% respectively. The ACE polymorphism was not significantly associated with the type of myocardial infarction, the LV ejection fraction, the number of vessels diseased and patency of the vessel after thrombolysis. The polymorphism had no influence on in hospital mortality (P = 0.453). The ACE activity also showed no influence on in hospital mortality (P = 0.482). The age > 60 years, Male gender, occluded artery and severe LV dysfunction (LVEF < 35%) were predictors of in-hospital mortality on multivariate regression analysis.

Conclusion

There was no differences among ACE (I/D) polymorphism observed in STEMI population. Neither ACE I/D polymorphism nor ACE activity predicted in-hospital mortality inpatients admitted with acute STEMI.

Association of polymorphisms of zinc metalloproteinases with clinical response to stem cell therapy

AIM

The purpose of this study was to assess the associations of polymorphisms in two metalloproteinase genes-metalloproteinase-2 (MMP-2) and angiotensin converting enzyme (ACE)-with clinical response to autologous transplantation of mononuclear bone marrow cells (MBMC) in patients with acute myocardial infarction.

METHODS

The double centre study included 48 patients with a first acute myocardial infarction treated with primary coronary angioplasty, stent implantation and transplantation of MBMC. According to the changes in perfusion defect size, left ventricle ejection fraction, end-systolic volume and peak systolic velocity of the infracted wall (dSaMI) after cell therapy, the patients were retrospectively divided into group A (responders) and group B (non-responders). Genomic DNA was isolated from peripheral leukocytes by a standard technique using proteinase K. Three MMP-2 promoter (-1575G/A, -1306C/T and -790T/G) as well as I/D ACE gene polymorphisms were detected by PCR methods with restriction analyses (when necessary) according to standard protocols.

RESULTS

Of the 48 patients who received MBMC transplantation, 17 responded to the therapy. There were no significant differences in the prevalence of matrix metalloproteinase-2 triple genotype GGCCTT between responder/non-responder groups (71% versus 61%, p=0.375). Similarly, no differences in either genotype distribution or allelic frequencies of I/D ACE polymorphism between responders and non-responders to the cell therapy were observed (p=0.933). Compared to patients with ACE genotype ID or DD, the patients with ACE II genotype significantly improved in regional systolic LV function of the infarcted wall after implantations of MBMC (dSaMI - 0.4 versus 1.4 cm/s, p=0.037).

CONCLUSION

In our study, the ACE genotype II was associated with improvement of regional systolic LV function of the infarcted wall after implantations of MBMC. The detected polymorphism in matrix metalloproteinase-2 gene was not associated with clinical response to cell therapy.

ACE gene insertion/deletion polymorphism has a mild influence on the acute development of left ventricular dysfunction in patients with ST elevation myocardial infarction treated with primary PCI

Background

We evaluated the associations among angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism, ACE activity and post-myocardial infarction (MI) left ventricular dysfunction and acute heart failure (AHF) early after presentation with MI with ST-segment elevation (STEMI).

Methods

A total of 556 patients with STEMI treated by primary PCI (421 patients without AHF and 135 patients with AHF) were the study population. The activity of BNP, NT-ProBNP and ACE were measured at hospital admission and 24 h after MI onset. Left ventricular angiography was done before PCI; echocardiography was undertaken between the third and fifth day after MI.

Results

In comparison with the II genotypes group, the DD/ID group had a higher level of ACE activity upon hospital admission (p < 0.001). We found a significantly higher level of ACE activity in patients with moderate LV dysfunction (EF 40-54%) in comparison both with patients with preserved LV function (EF ≥55%) and with patients with severe LV dysfunction (p = 0.028). A non-significant trend towards a higher incidence of mild AHF (22.1% vs. 16.02%, p = 0,093), a significantly higher value of end-systolic volume (ESV/BSA) (30.0 ± 12.3 vs. 28.5 ± 13.0; p < 0.05) and lower EF (50.2 ± 11.1 vs. 52.7 ± 11.7; p < 0.05) in the DD/ID genotypes group was noted. Even after multiple adjustments according to multivariate models, the EF for the DD/ID group remained significantly lower (p = 0,033). The DD/ID genotypes were associated with a significantly higher risk of EF <45% (OR 2.04 [95% CI 1.28; 3.25]).

Conclusions

These results suggest that the I/D polymorphism of ACE is associated with the development of LV dysfunction in the acute phase after STEMI. We demonstrated for the first time an association of the low ACE activity with the severe LV dysfunction, although patients with moderate LV dysfunction had higher level ACE activity than patients with preserved LV function.

The relationship between angiotensin-converting enzyme (insertion/deletion) gene polymorphism and left ventricular remodeling in acute myocardial infarction

BACKGROUND

The development of left ventricular remodeling after acute myocardial infarction is a predictor of heart failure and mortality. The genetic influence on cardiac remodeling in the early period after acute myocardial infarction, is however, unclear. The aim ofthis study was to investigate the relationship between angiotensin-converting enzyme (ACE) gene polymorphism and left ventricular remodeling in the early period in patients with anterior myocardial infarction.

METHOD

The study population consisted of 142 patients with their first attack of acute anterior myocardial infarction. Echocardiographic examinations were performed within 24 h of the first attack (first evaluation) and on the fifth day of acute myocardial infarction (second evaluation). Left ventricular end systolic and diastolic diameters, left ventricular end systolic and diastolic volumes, ejection fraction, mitral flow velocities (E, A, E/A), deceleration time, isovolumic relaxation time and myocardial performance index were calculated. ACE I/D polymorphism was determined using polymerase chain reaction amplification.

RESULTS

On the basis of polymorphism of the ACE gene, the patients were classified into the three groups: group 1, deletion/deletion (n=59) genotype, group 2 insertion/deletion (n=69), and group 3 insertion/insertion (n=14) genotype. When the first and second sets of echocardiographic results of the groups were compared, all parameters were not different among three groups. In group analysis, Left ventricular systolic diameters, left ventricular diastolic diameters, left ventricular end diastolic diameters, left ventricular ejection fraction and myocardial performance index between first and second echocardiographic results were significantly different in deletion/deletion group and only myocardial performance index and left ventricular ejection fraction in insertion/deletion group (P<0.05).

CONCLUSIONS

ACE gene polymorphism may influence early cardiac remodeling after acute myocardial infarction. Patients with the deletion/deletion-insertion/deletion genotype may be particularly more sensitive to ACE-I treatment possibly owing to the more prominent role of the renin-angiotensin system.

Pharmacogenomics of Renin Angiotensin System Inhibitors in Coronary Artery Disease

Renin Angiotensin System (RAS) inhibitors comprise some of the most commonly used medications in coronary artery disease (CAD) and its related syndromes. Unfortunately, significant inter-patient variability seems likely in response to these agents; of which, the influence of genetic determinants is of interest. This review summarizes the available RAS inhibitor pharmacogenomic studies which have evaluated RAS polymorphisms that either elucidate mechanism via surrogate endpoint measurements, or predict efficacy via clinical outcomes in CAD related syndromes.Regardless of the endpoint, none of the RAS genotypes conclusively predicts efficacy of RAS inhibitors. In fact, the results of the pharmacogenomic studies were often in direct conflict with one another. Varied results appear due to methodological limitations (e.g., inadequate study power, genotyping error, methods of endpoint measurement), study conceptualization (e.g., overestimating the contribution of polymorphism to disease, lack of haplotype approach), and differences between studies (e.g., genotype frequency, study subject characteristics, the specific medication and dose used). Thus investigators should consider the various methodological limitations to improve upon the current approach to RAS inhibitor pharmacogenomic research in the vast CAD population.

A prospective evaluation of left ventricular remodeling after inaugural anterior myocardial infarction as a function of gene polymorphisms in the renin-angiotensin-aldosterone, adrenergic, and metalloproteinase systems

BACKGROUND

Left ventricular remodeling (LVR) is a strong predictor of cardiovascular events after myocardial infarction (MI). Although several factors have been shown to influence LVR, interindividual variability exists. Some studies have suggested that gene polymorphisms may be associated with LVR, but these studies were limited by either a retrospective design or the inclusion of limited patient numbers. The present study was designed to prospectively assess the impact of gene polymorphisms on LVR.

METHODS

We included 266 patients with inaugural anterior MI. Systematic echocardiographic follow-ups were performed at 3 months and at 1 year after MI. The polymorphisms were selected using a candidate gene approach based on LVR pathophysiology. We analyzed 14 polymorphisms in 3 different systems: the renin-angiotensin-aldosterone system (ACE I/D, RAT1 1166A/C, angiotensinogen M235T, CYP11B2 -344C/T), the adrenergic system (beta1AR Ser49Gly, beta1AR Gly389Arg, beta2AR Gly16Arg, beta2AR Gln27Glu, beta2AR Thr164Ile, alpha2cAR Del322-325), and the metalloproteinase (MMP) system (-1607 1G/2G MMP-1, -1306 C/T MMP-2, -1171 5A/6A MMP-3, -1562 C/T MMP-9).

RESULTS

Left ventricular remodeling was documented by a progressive increase in end-diastolic volume from 56.5 +/- 14.9 mL/m2 at baseline to 62.8 +/- 18.8 mL/m2 at 1 year (P < .0001). End-diastolic volume at baseline, 3 months, or 1 year did not differ significantly among genotypes for any polymorphism. The change in end-diastolic volume from baseline to 1 year was also similar among genotypes for all polymorphisms.

CONCLUSIONS

Left ventricular remodeling after MI is not associated with common polymorphisms in the renin-angiotensin-aldosterone, adrenergic, or MMP systems.

Association Between A/C1166 Gene Polymorphism of the Angiotensin II Type 1 Receptor and Biventricular Functions in Patients With Acute Myocardial Infarction

BACKGROUND

Although there have been several association studies of angiotensin II type 1 receptor (AT1R, A/C1166) gene polymorphism in clinical endpoints such as myocardial infarction (MI), hypertension, aortic stiffness, and left ventricular mass, the relationship between AT1R polymorphism and biventricular function in acute anterior MI has not been studied before.

METHODS AND RESULTS

The study group comprised 132 consecutive patients who were admitted to the coronary care unit with their first acute anterior MI. Systolic and diastolic diameters, volumes, inflow properties, ejection fraction and myocardial performance index of both ventricles were measured. AT1R polymorphism was determined using polymerase chain reaction amplification. Based on A/C1166 polymorphism of AT1R, the patients were classified into 3 groups: group 1, A/A (n=91) genotype, group 2 A/C (n=28), and group 3 C/C (n=13) genotype. When the left ventricular and right ventricular echocardiographic functions were compared, all parameters of the 3 groups were found to be similar. No difference was detected in either the genotype distribution or allele frequencies between the patients and the controls for AT1R.

CONCLUSIONS

The results suggest that A/C1166 polymorphism of AT1R did not influence the risk of either acute MI or biventricular function after anterior MI.

Rethinking the renin-angiotensin system and its role in cardiovascular regulation

Angiotensin-converting enzyme (ACE) plays a pivotal role in the renin-angiotensin system (RAS) and ACE-inhibitors are widely used in several clinical conditions, including hypertension and heart failure. Recently, a homologue of ACE, ACE(2) has been discovered. Both ACE and ACE(2) are emerging as key enzymes of the RAS, where ACE(2) may play a role as negative regulator of ACE. Moreover, ACE(2) appears to be an important enzyme outside the classical RAS, as it hydrolyzes apelins, dynorphin A 1-13, des-Arg-bradykinin and other peptide substrates. The precise interplay between tissue ACE, ACE(2), and their substrates and by-products are presently still unclear.ACE-inhibitors reduce angiotensin II formation and bradykinin degradation, but do not inhibit ACE(2) activity. Moreover, ACE-inhibitors differ in their affinity for tissue ACE, and it has been suggested that tissue ACE affinity might be responsible for some of the beneficial properties of these drugs. ACE-inhibitors also increase nitric oxide availability, and activate several kinases that may regulate protein synthesis by interacting with the nucleus of the cells (outside-in signaling). The outside-in signaling may also be activated by bradykinin itself. Although, the precise significance of the outside-in signaling is still unclear, this new role of ACE-inhibitors may represent a discriminant factor versus angiotensin II receptors antagonists. This mini review will summarize some new aspects concerning the recently discovered biological functions of RAS and in particular of ACE, ACE(2) and ACE-inhibitors in cardiovascular system.

Genetic polymorphisms and heart failure

Heart failure is a complex clinical syndrome. There is evidence for a genetic contribution to the pathophysiology of heart failure. Considering the fundamental role of neurohormonal factors in the pathophysiology and progression of cardiac dysfunction and hypertrophy, variants of genes involved in this system are logical candidate genes in heart failure. In this report, genetic polymorphisms of the major neurohormonal systems in heart failure will be discussed. Studies on polymorphisms of the renin-angiotensin-aldosterone system (RAAS), adrenergic receptor polymorphisms, endothelin (receptor) polymorphisms, and a group of miscellaneous polymorphisms that may be involved in the development or phenotypic expression of heart failure will be reviewed. Research on left ventricular hypertrophy is also included. The majority of genetic association studies focused on the ACE I/D polymorphism. Initial genetic associations have often been difficult to replicate, mainly due to problems in study design and lack of power. Promising results have been obtained with genetic polymorphisms of the RAAS and sympathetic system. Considering the evidence so far, a modifying role for these polymorphisms seems more likely than a role of these variants as susceptibility genes. Besides the need for larger studies to examine the effects of single nucleotide polymorphisms and haplotypes, future studies also need to focus on the complexity of these systems and study gene-gene interactions and gene-environment interactions.

ACE inhibitors and angiotensin II receptor antagonists

The biological actions of angiotensin II (ANG), the most prominent hormone of the renin-angiotensin-aldosterone system (RAAS), may promote the development of atherosclerosis in many ways. ANG aggravates hypertension, metabolic syndrome, and endothelial dysfunction, and thereby constitutes a major risk factor for cardiovascular disease. The formation of atherosclerotic lesions involves local uptake, synthesis and oxidation of lipids, inflammation, as well as cellular migration and proliferation--mechanisms that may all be enhanced by ANG via its AT1 receptor. ANG may also increase the risk of acute thrombosis by destabilizing atherosclerotic plaques and enhancing the activity of thrombocytes and coagulation. After myocardial infarction, ANG promotes myocardial remodeling and fibrosis, and its many pathological mechanisms deteriorate the prognosis of these high-risk patients in particular. Therapeutically, inhibitors of the angiotensin I-converting enzyme (ACEI) and AT1 receptor blockers (ARB) are available to suppress the generation and cellular signaling of ANG, respectively. Despite major differences in the efficacy of ANG suppression and the modulation of other hormones and receptors, both classes of drugs are generally effective in attenuating numerous pathomechanisms of ANG in vitro, and in diminishing the development of atherosclerotic lesions and restenosis after angioplasty in various animal models. In clinical therapy, ACEI and ACE are well-tolerated antihypertensive drugs that also improve the prognosis of heart failure patients. After myocardial infarction and in stable coronary heart disease, ACEI have been shown to reduce mortality in a manner independent of hemodynamic alterations. However, there is little evidence that inhibitors of the RAAS may be effective against arterial restenosis, and a possible benefit of these substances compared to other antihypertensive drugs in the primary prevention of coronary heart disease in hypertensive patients is still a matter of debate, possibly depending on the specific substance and condition being investigated. As such, the general clinical efficacy of ACEI and ARB may be due to a positive influence on hemodynamic load, vascular function, myocardial remodeling, and neuro-humoral regulation, rather than to a direct attenuation of the atherosclerotic process. Further therapeutic advances may be achieved by identifying optimum drugs, patient populations, and treatment protocols.

The Role of Angiotensin-Converting Enzyme Polymorphism in Congestive Heart Failure

Angiotensin-converting enzyme (ACE) is a zinc metallopeptidase, with primary known functions of converting angiotensin I into the vasoactive and aldosterone-stimulating peptide angiotensin II and inactivating bradykinin. There is high variability among individuals in ACE concentrations, mainly due to the presence of a genetic polymorphism. The ACE gene has, in fact, insertion/deletion polymorphism in intron 16, consisting of a 287-base pair Alu repeat sequence, with three genotypes: insertion polymorphism, insertion/deletion polymorphism, and deletion polymorphism. The genetic effect accounts for 47% of the total variance of serum ACE. The determination of this polymorphism has allowed researchers to study the implications of the ACE gene in many case-control studies of cardiovascular disease, including myocardial infarction and hypertrophic and dilated cardiomyopathy. We review the current knowledge about the ACE gene polymorphism and its implications in heart failure secondary to ischemic or idiopathic dilated cardiomyopathy. Interpretation of the results of studies about the role of this polymorphism are controversial. The repetition of epidemio-genetic studies and the creation of adequate experimental studies will help to definitively establish the pathogenetic role of the permanent increase in ACE expression associated with the deletion polymorphism genotype.

Left ventricular size, mass and function in relation to angiotensin-converting enzyme gene and angiotensin-II type 1 receptor gene polymorphisms in patients with coronary artery disease

The objective of the present study was to analyse the potential synergistic influence of the insertion/deletion polymorphism of the angiotensin-converting enzyme gene (I/D ACE) and the A1166C polymorphism of the angiotensin-II type 1 receptor gene polymorphisms (A1166C AT1R) on the left ventricular size and performance. Three hundred sixty and one consecutive, Caucasian patients with angiographically confirmed coronary artery disease (CAD) were enrolled into the study. Left ventricular diameter, mass and function were evaluated by echocardiography. Screening for the I/D ACE and A1166C AT1R genotypes was performed by polymerase chain reaction of genomic DNA, followed by restriction enzyme digestion and agarose gel electrophoresis. The I/D ACE and A1166C AT1R genotypes separately were not significantly associated with the left ventricular size and function parameters in CAD patients. However, trends towards decreased left ventricular ejection fraction (LVEF) as well as increased left ventricular end-diastolic diameter (LVEDD) and left ventricular mass index (LVMI) were observed when patients with genotype DD+CC/AC and DD+CC were compared to patients homozygous only in one locus (DD or CC). Significant increase in LVEDD and LVMI was observed only in patients with a history of anterior myocardial infarction with combined genotype DD+CC/AC or DD+CC. This study does not support the role of the ACE I/D and AT1R A1166C polymorphisms in the determination of the left ventricular size and performance in patients with significant coronary atherosclerosis. However, it indicates that the influence of polymorphisms may be present in specific patient populations.

A prospective evaluation of the angiotensin-converting enzyme D/I polymorphism and left ventricular remodeling in the 'Healing and Early Afterload Reducing Therapy' study

The D/I (deletion, D, insertion, I) polymorphism of the angiotensin-converting enzyme (ACE) gene has been extensively studied for its association with a number of cardiovascular and other disease states. However, its potential association with differential clinical efficacy of ACE inhibitors (ACE-I) administered to patients who had suffered a myocardial infarction (MI), i.e. the prevention of left ventricular (LV) remodeling, has so far not been specifically studied. The aim of the study was to investigate whether the D/I polymorphism of the ACE gene is associated with the incidence of post-MI LV remodeling in patients drawn from the 'Healing and Early Afterload Reducing Therapy' (HEART) Study. The ACE D/I polymorphism was characterized by the polymerase chain reaction (PCR) in 265 subjects from the 'Healing and Early Afterload Reducing Therapy' Study, a double-blind, placebo-controlled trial with the objective of determining whether early or delayed administration of the ACE-I, ramipril, in patients with acute anterior wall MI would be optimal in reducing LV enlargement. Selected frequencies for the ACE D and I alleles were 0.59 and 0.41 (placebo-high dose group), 0.56 and 0.44 (low dose-low dose group), and, 0.60 and 0.40 (high dose-high dose group), respectively. All observed genotype frequencies were in Hardy-Weinberg equilibrium. There was no evidence for an association between genotype and outcome regarding LV size or function, nor with the initial blood pressure response after ACE-I administration (adjusted for covariates). Our data provide no evidence for an association of the ACE D/I polymorphism with the risk of LV remodeling post-MI in the presence of ACE-I therapy, and therefore do not suggest that differential clinical efficacy of ACE-inhibitors is related to this genetic marker.

The relevance of tissue angiotensin-converting enzyme: manifestations in mechanistic and endpoint data

Angiotensin-converting enzyme (ACE) is primarily localized (>90%) in various tissues and organs, most notably on the endothelium but also within parenchyma and inflammatory cells. Tissue ACE is now recognized as a key factor in cardiovascular and renal diseases. Endothelial dysfunction, in response to a number of risk factors or injury such as hypertension, diabetes mellitus, hypercholesteremia, and cigarette smoking, disrupts the balance of vasodilation and vasoconstriction, vascular smooth muscle cell growth, the inflammatory and oxidative state of the vessel wall, and is associated with activation of tissue ACE. Pathologic activation of local ACE can have deleterious effects on the heart, vasculature, and the kidneys. The imbalance resulting from increased local formation of angiotensin II and increased bradykinin degradation favors cardiovascular disease. Indeed, ACE inhibitors effectively reduce high blood pressure and exert cardio- and renoprotective actions. Recent evidence suggests that a principal target of ACE inhibitor action is at the tissue sites. Pharmacokinetic properties of various ACE inhibitors indicate that there are differences in their binding characteristics for tissue ACE. Clinical studies comparing the effects of antihypertensives (especially ACE inhibitors) on endothelial function suggest differences. More comparative experimental and clinical studies should address the significance of these drug differences and their impact on clinical events.

Both alleles of the M235T polymorphism of the angiotensinogen gene can be a risk factor for myocardial infarction

We have studied the role of three polymorphic genes of the renin-angiotensin system (RAS) as independent risk factors for myocardial infarction (MI) and their correlation with three of the major coronary risk factors: serum cholesterol (CH), hypertension (HT) and smoking (SM). A population of 392 men was genotyped for the M235T polymorphism of the angiotensinogen (AGT) gene, the insertion/deletion of the angiotensin-converting enzyme (ACE) and the all66c of the angiotensin-II type 1 receptor (AT1R), by means of polymerase chain reaction (PCR) and restriction enzyme analysis. It was observed that the T allele frequency increased significantly in the MI with HT, CH, and SM subgroup (0.58 vs 0.31) (p<0.01). In contrast, the M allele frequency was higher in the MI without HT, CH, and SM (0.69 vs 0.42) (p<0.01). A strong association between the MM genotype and MI (p<0.001, odds ratio=4.29, confidence interval=1.95-9.42) was found when age-matched MM control subjects were compared to MI individuals with none of the other known major coronary risk factors. Futhermore, subjects with the MM genotype showed a significantly higher plasma renin activity (PRA) profile than those with the TT genotype (p<0.001). It can be concluded that the M allele is an independent risk factor for MI and the T allele modified the risk when other major risk factors are present.

A role of angiotensin-converting enzyme gene polymorphism in left ventricular remodeling after myocardial infarction

BACKGROUND

Left ventricular remodeling (LVR) process is one of the important secondary sequele after acute myocardial infarction (AMI). However, little is known about the relationship between LVR and angiotensin converting enzyme (ACE) gene polymorphism as well as endothelial nitric oxide synthase (ecNOS) gene polymorphism.

METHODS

Coronary angiography and left ventriculography were performed within 24 hours and 30+/-7 days after AMI onset. All consecutive 24 patients (57+/-6 years) had acute anterior MI with one vessel disease of left anterior descending artery and successful revascularization therapy during acute phase. Patients were divided into three groups according to the change of end-diastolic volume index (EDVI)(Delta EDVI = EDVI 1 month-EDVI within 24 hrs); LVR(+) (Delta EDVI>7.0 ml/m(2), n = 5), LVR (-)(Delta EDVI<-7.0 ml/m(2), n = 13), and LVR (+/-)(-7.0<Delta EDVI<7.0 ml/m(2), n = 6) groups. The polymorphisms of ACE and ecNOS gene were determined with PCR method after an extraction of genomic DNA from peripheral leukocytes.

RESULTS

There were no significant difference among three groups as to baseline characteristics, including coronary risk factors, medications, serum CPKmax and patency of infarct-related artery. The incidence of DD genotype of ACE gene is significantly higher in LVR (+) than in the other two groups (0.60; 0; 0, respectively, chi(2) = 13.150, p<0.01). The incidence of D allele of ACE gene is also significantly higher in LVR (+) than in the other two groups (0.70; 0.17; 0.19, respectively, chi(2) = 10.221, p<0.01). Delta EDVI of DD genotype was significantly greater than in the other two groups (DD genotype = 30.1+/-18.1; ID genotype = -13.0+/-27.4; II genotype = -8.2+/-11.5 ml/m(2), respectively, p<0.05). There was no significant difference in ecNOS gene polymorphism among three groups. By stepwise regression analysis, the significant independent predictors of Delta EDVI were EDVI within 24 hrs and DD genotype (F = 16.88 and 8.641, respectively, p = 0.0024).

CONCLUSION

These results showed that left ventricular dilatation is related to DD genotype of ACE gene after successful reperfusion therapy of anterior AMI. Thus, renin-angiotensin system may play an important role in left ventricular remodeling after AMI.

Insertion/deletion polymorphism in the angiotensin-converting enzyme gene affects heart weight

BACKGROUND

Angiotensin (Ang) II, a major regulatory factor for left ventricular mass, is generated from Ang I by ACE. ACE levels are associated with an insertion/deletion (I/D) polymorphism in the ACE gene. The ACE polymorphism should result in varied Ang II concentrations and hence affect left ventricular mass. We therefore investigated whether ACE genotype is a predictor of heart weight.

METHODS AND RESULTS

From 693 consecutive patients autopsied between 1994 and 1998 in our hospital, patients with valvular disease, myocardial infarction, or cardiomyopathy were excluded. The remaining 443 autopsy patients were the subjects of our study. The heart weight at autopsy was corrected for body surface area. Genomic DNA was purified from the kidney, and ACE genotype was determined by polymerase chain reaction. Heart weight in the DD genotype (249. 9+/-49.9 g/m(2)) was significantly higher than that in the ID (230. 0+/-51.2 g/m(2); P<0.05) and II (226.8+/-49.8 g/m(2); P<0.01) genotypes. Heart weight was also positively related to age (r=0.145, P<0.0001) and coronary stenosis index (r=0.147, P=0.0019). Multiple regression analysis showed that a history of hypertension (P<0.0001), age (P=0.0001), and DD genotype (P=0.0154) were independent predictors of heart weight.

CONCLUSIONS

ACE genotype predicts cardiac mass; however, it was less effective than epigenetic factors such as hypertension or age.

M235T angiotensinogen gene polymorphism and cardiovascular renal risk

OBJECTIVE

In this meta-analysis, we attempted to derive pooled estimates for the putative associations between various cardiovascular-renal disorders and the M235T polymorphism of the angiotensinogen gene.

METHODS

Case-control studies were combined, using the Mantel and Haenszel approach. Joint P values for continuous variables were calculated by Stouffer's method. Continuous measurements reported in different units were expressed on a percentage scale using the intrastudy mean of the MM genotype as denominator.

RESULTS

The computerized database used for this analysis included 69 reports with an overall sample size of 27,906 subjects. Overall, possession of the T allele was associated with an increased risk of hypertension. In comparison with the MM reference group (number of studies, n = 32), the excess risk was 31% (P = 0.001) in TT homozygotes and 11% (P = 0.03) in TM heterozygotes. The sensitivity analysis showed that this association was present only in whites (T allelic frequency, f = 42.2%), but not in blacks (f = 77.0%) or Asians (f = 78.0%). Atherosclerotic complications (n = 12), renal microvascular disorders (n = 13), cardiomyopathy (n = 2) or diabetic retinopathy (n = 3) were not correlated with the M235T polymorphism. Publication bias was observed for hypertension, but not for coronary heart disease, including myocardial infarction, and for microvascular nephropathy. Furthermore, in comparison with the MM control group, the circulating angiotensinogen levels (n = 8) were raised by 11 and 7% (P = 0.01) in TT and TM subjects, respectively. In contrast, plasma levels of the angiotensin I converting enzyme (n = 4) and body mass index (n = 15) were not associated with the T allele.

CONCLUSION

The T allele encoding angiotensinogen is not associated with atherosclerotic or microvascular complications, but in Caucasians behaves as a marker for hypertension. This association, which may have been inflated by publication bias, does not necessarily imply causality.

The deletion/insertion polymorphism of the angiotensin converting enzyme gene and cardiovascular-renal risk

OBJECTIVE

This meta-analysis attempted to derive pooled estimates for the associations between various cardiovascular-renal disorders and the deletion/insertion (D/I) polymorphism of the angiotensin converting enzyme (ACE) gene.

METHODS

Case-control studies were combined, using the Mantel-Haenszel approach. Joint P values for continuous variables were calculated by Stouffer's method. Continuous measurements reported in different units were expressed on a percentage scale using the within-study mean of the II genotype as the denominator.

RESULTS

The computerized database used for this analysis included 145 reports with an overall sample size of 49 959 subjects. Overall, possession of the D allele was associated with an increased risk of atherosclerotic and renal microvascular complications. In comparison with the II reference group, the excess risk in DD homozygotes (P < 0.001) was 32% for coronary heart disease (CHD; 30 studies), 45% for myocardial infarction (20 studies), 94% for stroke (five studies) and 56% for diabetic nephropathy (11 studies). The corresponding risk in DI heterozygotes amounted to 11% (P= 0.02), 13% (P= 0.02), 22% (P= 0.10) and 40% (P < 0.001), respectively. Hypertension (23 studies), left ventricular hypertrophy (five studies), hypertrophic or dilated cardiomyopathy (eight studies) and diabetic retinopathy (two studies) were not related to the DI polymorphism. Publication bias was observed for CHD, myocardial infarction and microvascular nephropathy, but not hypertension. In studies with DNA amplification in the presence of insertion-specific primers, the risk associated with the DD genotype increased to 150% [95% confidence interval (CI) 76-256; four studies] for diabetic nephropathy, but decreased to 12% (95% CI -3 to 28; seven studies) for CHD and 14% (95% CI -6 to 37; four studies) for myocardial infarction. On the other hand, the pooled odds ratios did not materially change if the meta-analysis was limited to articles published in journals with an impact factor of at least 4. Furthermore, compared with the II control group, the circulating ACE levels (29 studies) were raised 58 and 31% (P < 0.001) in DD and DI subjects, respectively. In contrast, plasma renin (10 studies), systolic and diastolic blood pressure (46 studies) and body mass index (30 studies) were not associated with the D allele.

CONCLUSION

The D allele is not associated with hypertension, but behaves as a marker of atherosclerotic cardiovascular complications and diabetic nephropathy. These associations do not necessarily imply a causal relationship and may have been inflated by publication bias. Nevertheless, their possible therapeutic implications may be subject to further investigation in prospective (intervention) studies.

The II genotype of the angiotensin-converting enzyme gene delays the onset of acute coronary syndromes

The DD genotype of the angiotensin-converting enzyme (ACE) gene has been reported to be a risk factor for myocardial infarction. However, this association has not been confirmed in some populations. We hypothesized that the discrepancies between these studies may be due to their definition of ischemic heart diseases. According to the genotype of the ACE gene, we analyzed the profiles of 320 patients who underwent coronary angiography for possible ischemic heart diseases. Of these, 23 patients had no significantly diseased vessels and no acetylcholine-induced vasospasm (normal acetylcholine responder [NAR]) (II, 7; ID, 14; DD, 2), 34 patients had no significantly diseased vessels and acetylcholine-induced vasospasm (paradoxical acetylcholine responder: [PAR]) (II, 15; ID, 18; DD, 1), 80 angina pectoris (AP) patients had significantly diseased vessels (II, 41; ID, 37; DD, 2), and 183 patients demonstrated myocardial infarction (MI) (II, 67; ID, 91; DD, 25). The frequency of the DD genotype was significantly lower in PAR and AP patients than in those with MI (P = .0344). Next we analyzed the length of time between the first anginal pain and the onset of myocardial infarction in the MI group. We obtained reliable information regarding this period in 149 of the 183 patients. This period was significantly shorter in the ID and DD groups than in the II group (P = .0022). Multiple regression analyses revealed that this period was significantly determined (P = .0003, R = .324) by the genotype of the ACE gene (II = 1, ID + DD = 2, P = .0003) and age (P = .034). The D allele of the ACE gene and lower age were associated with a shorter period. On the other hand, the genotype of the ACE gene had no significant effect on the number of significantly diseased (> 50%) lesions. The frequency of the D allele in subjects with a rapid progression of MI was significantly higher than that in subjects with a prolonged history of stable AP (P < .0001). In summary, the II genotype of the ACE gene was associated with a longer period of time between the first anginal pain and the onset of myocardial infarction than the ID and DD genotypes of the ACE gene.

Effect of genotype on the angiotensin-converting enzyme mRNA level in human atria

1. To clarify the mechanism of the association between I/D polymorphism of the angiotensin-converting enzyme (ACE) gene and various cardiovascular disease, ACE mRNA levels in human atrial appendages were assessed in relation to the genotype of the ACE gene. 2. Angiotensin-converting enzyme mRNA levels were positively correlated with age and tended to show a positive correlation with mean pulmonary pressure (mPA). Multiple regression analysis indicated that age and mPA, but not the genotype of the ACE gene, were predictors of ACE mRNA levels in human atrial appendages. 3. The present study indicates that I/D polymorphism of the ACE gene is not simply reflected in ACE mRNA levels and that further study is needed to determine the mechanism of the association between this polymorphism and various cardiovascular diseases.