Bradykinin stimulates the release of tissue plasminogen activator in human coronary circulation: effects of angiotensin-converting enzyme inhibitors

OBJECTIVES: The goal of this study was to determine: 1) whether bradykinin (BK) directly stimulates tissue plasminogen activator (tPA) secretion in human coronary circulation, and 2) whether angiotensin-converting enzyme (ACE) inhibition favorably alters the fibrinolytic balance regulated by BK. BACKGROUND: Bradykinin is a potent stimulator of tPA secretion in endothelial cells; however, the effect of BK on tPA release in the human coronary circulation has not been studied. METHODS: Fifty-six patients with atypical chest pain were randomly assigned to two groups: 25 patients were treated with the ACE inhibitor enalapril (ACE inhibitor group), and 31 were not treated with ACE inhibitors (non-ACE inhibitor group). Graded doses of BK (0.2, 0.6, 2.0 microg/min), acetylcholine (ACh) (30 microg/min) and papaverine (PA) (12 mg) were administered into the left coronary artery. Coronary blood flow (CBF) was evaluated by Doppler flow velocity measurement. Blood samples were taken from the aorta (Ao) and the coronary sinus (CS). RESULTS: Bradykinin induced similar increases in CBF in both groups. The net tPA release induced by BK was dose-dependently increased in both groups, and the extent of that increase in the ACE inhibitor group was greater than that in the non-ACE inhibitor group. Bradykinin did not alter plasminogen activator inhibitor-1 (PAI-1) levels in the Ao or CS in either group. Neither ACh nor PA altered tPA levels or PAI-1 levels in either group. CONCLUSIONS: Intracoronary infusion of BK stimulates tPA release without causing any change in PAI-1 levels in the human coronary circulation. In addition, this effect of BK is augmented by an ACE inhibitor.     

Contribution of bradykinin receptor dysfunction to abnormal coronary vasomotion in humans

OBJECTIVES: The aim of our study was to investigate coronary vascular kinin receptor function in patients with atherosclerosis or its risk factors. BACKGROUND: Although acetylcholine (ACH) is used as a probe for testing vascular function in vivo, endogenous bradykinin (BK) regulates resting and flow-mediated epicardial tone. METHODS: In 53 patients with mild atherosclerosis or its risk factors and 9 control subjects, endothelium-dependent vasomotion was tested with intracoronary ACH (30 microg/min) and BK (62.5 ng/min and 4 microg/min), and endothelium-independent function with sodium nitroprusside. Metabolic vasodilation was assessed during cardiac pacing (n = 19). Correlation with serum angiotensin-converting enzyme (ACE) levels and the ACE insertion/deletion genotype was performed. RESULTS: There was progressive impairment in ACH-mediated microvascular dilation with increasing numbers of risk factors (p = 0.025, analysis of variance). By contrast, BK- and sodium nitroprusside-mediated microvascular dilation was similar in all groups. Similarly, there was no correlation between epicardial coronary responses to ACH and BK; segments that constricted or dilated with ACH had similar dilator responses with BK. Bradykinin, but not ACH-mediated vasomotion, was depressed in epicardial segments that constricted with pacing. Finally, epicardial BK responses were depressed in patients with high ACE levels and in those with the ACE DD genotype. CONCLUSIONS: Endothelial dysfunction in atherosclerosis appears to be receptor-specific, involving the muscarinic receptor with relative sparing of the kinin receptor pathways. Abnormal reactivity of epicardial coronary arteries during physiologic stress is better represented by BK and not by ACH responses. Bradykinin activity and, hence, physiologic coronary vasomotion appears to be influenced by serum ACE levels and the ACE insertion/deletion genotype.     

ACE/DD genotype is associated with hemostasis balance disturbances reflecting hypercoagulability and endothelial dysfunction in patients with untreated hypertension

BACKGROUND: Angiotensin-converting enzyme (ACE) gene polymorphism has been associated with an increased incidence of myocardial infarction. Recent studies have investigated a potential influence of ACE gene polymorphism on fibrinolysis or endothelial function. It has been previously established that essential hypertension is accompanied by endothelial dysfunction and fibrinolytic balance disorders. The aim of our study was to study the relation between ACE gene polymorphism and fibrinolytic/hemostatic factors as well as endothelial cell damage markers in patients with hypertension. METHODS: The following parameters were evaluated in 104 patients with previously untreated hypertension: plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA) antigen, fibrinogen, D-dimer, and von Willebrand factor (vWF). The genotype of the ACE gene was also determined (by the polymerase chain reaction method), and patients were characterized according to the observed alleles as deletion/deletion (DD), insertion/insertion (II), or insertion/deletion (ID). RESULTS: Those with DD genotype (n = 42) had significantly higher plasma levels of PAI-1 antigen (P =. 012), tPA antigen (P =.0001), fibrinogen (P =.0002), D-dimer (P =. 0001) and vWF (P =.0004) compared with ID (n = 30) or II (n = 32) genotypes. The ACE gene genotypes appeared to be significant predictors for plasma PAI-1 antigen, tPA antigen, fibrinogen, D -dimer, and vWF even after adjustment for age, sex, body mass index, triglyceride and cholesterol levels, and blood pressure. CONCLUSIONS: Our findings suggest that the ACE/DD genotype is associated with hemostasis balance disturbances reflecting hypercoagulability and endothelial damage in patients with untreated hypertension.     

Ethnicity affects vasodilation,but not endothelial tissue plasminogen activator release,in response to bradykinin

Previous studies indicate that the vasodilator response to bradykinin (BK) and other endothelium-dependent and -independent agonists is decreased in black Americans compared with white Americans. The purpose of the present study was to determine the effect of ethnicity on fibrinolytic function in humans. Graded doses of BK (100, 200, and 400 ng/min), acetylcholine (15, 30, and 60 microg/min; N=20), or methacholine (3.2, 6.4, 12.8 microg/min; N=20), and sodium nitroprusside (0.8, 1.6, and 3.2 microg/min) were infused via brachial artery in 19 white and 21 black age-matched normotensive subjects. Forearm blood flow (FBF) was measured by plethysmography, and venous and arterial samples were collected for tissue plasminogen activator (tPA) antigen. Compared with whites (increase in FBF from 3.7+/-0.5 to 23.9+/-2.5 mL x min(-1) x 100 mL(-1)), blacks (increase in FBF from 2.8+/-0.3 to 15.2+/-1.9 mL x 100 mL(-1) x min(-1)) exhibited a blunted FBF response to BK (P=0.035). Responses to sodium nitroprusside and methacholine or acetylcholine were similarly decreased. In contrast, there was no effect of ethnicity on net tPA antigen release in response to BK (increase from -0.2+/-0.4 to 67.3+/-15.2 ng x min(-1) x 100 mL(-1) in blacks; from 0.04+/-0.9 to 65.9+/-13.6 ng x min(-1) x 100 mL(-1) in whites). Thus, ethnicity significantly influenced the relationship between the flow and tPA release responses to BK (P=0.037). These data suggest that the BK-dependent alterations in vascular fibrinolytic function are preserved in black Americans compared with white Americans.     

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.     

Angiotensin-converting enzyme inhibition but not angiotensin II type 1 receptor antagonism augments coronary release of tissue plasminogen activator in hypertensive patients

OBJECTIVES: We compared the effects of perindopril and losartan on endothelium-dependent coronary vasomotor and fibrinolytic function. BACKGROUND: The renin-angiotensin system regulates the vascular fibrinolytic balance. However, the effects of angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor antagonists on coronary fibrinolytic function have not been compared in hypertensive patients. METHODS: Forty-five patients with hypertension were randomly assigned to three groups: 16 patients were treated with perindopril (4 mg/day) for four weeks; 15 were treated with losartan (50 mg/day) for four weeks; and 14 were not treated with either perindopril or losartan (control group). Graded doses of bradykinin (BK) (0.2, 0.6, and 2.0 microg/min) were administered into the left coronary artery. Coronary blood flow (CBF) was evaluated by Doppler flow velocity measurement. RESULTS: Bradykinin induced dose-dependent increases in CBF in all groups. The increases in CBF induced by BK in the perindopril and losartan groups were significantly greater than those in the control group. Net coronary tissue-type plasminogen activator (t-PA) release was enhanced by BK in all groups, and the increase in the perindopril group was greater than that in the losartan and control groups. Bradykinin did not alter plasminogen activator inhibitor type 1 levels in any of the groups. CONCLUSIONS: Perindopril and losartan similarly augment BK-induced coronary vasodilation. Perindopril may have a greater potential to enhance the BK-induced coronary release of t-PA than losartan.     

DD angiotensin-converting enzyme gene polymorphism is associated with endothelial dysfunction in normal humans.

A polymorphism within the angiotensin-converting enzyme (ACE) gene may increase the risk of myocardial infarction in individuals previously thought to be at low cardiovascular risk. The mechanism through which it exerts this effect is unknown but may be due to increased angiotensin II-induced nitric oxide (NO) breakdown and/or reduced bradykinin-mediated NO release. We investigated whether endothelial function was different between different ACE genotypes. We performed a cross-sectional study comparing the endothelial function of the 3 genotypes (II: n=25; ID: n=31; DD: n=12). Mean+/-SD ages of the subjects were 24+/-4 (II), 25+/-6 (ID), and 25+/-6 (DD) years. We assessed the impact of the genotypes on endothelial function and found that the DD genotype was associated with a significant blunting in endothelial-dependent vasodilatation (forearm blood flow data are presented as mean+/-SD ratio of blood flow in response to 3 incrementally increasing doses of each vasoactive agent in the test arm to blood flow in the control arm; the comparison is between DD versus ID versus II; the P value is an expression of an overall difference by ANOVA, and the 95% CIs are of a pairwise comparison between genotypes): acetylcholine, 2.88+/-1.45 versus 3.81+/-1.93 versus 4.23+/-2.37 (P=0.002; 95% CI [II versus ID], -0.19 to 0.91; 95% CI [II versus DD], 0.36 to 1.80; 95% CI [ID versus DD], 0.02 to 1.42). There was also a significant difference with the endothelial-independent vasodilator sodium nitroprusside, with values of 2.11+/-1.00 versus 2.55+/-1.36 versus 2.75+/-1.18 (P<0.05; 95% CI [II versus ID], -0.15 to 0.51; 95% CI [II versus DD], 0.03 to 0.89; 95% CI [ID versus DD], -0.13 to 0.71), but not with verapamil. There was no effect of the ACE genotype on endothelial-dependent or -independent vasoconstrictors NG-monomethyl-L-arginine or norepinephrine. Investigating the effects of cigarette smoking on each genotype demonstrated that for II and DD genotypes, acetylcholine responses were further blunted if subjects smoked. These data demonstrate that the DD ACE genotype in a young population is associated with a blunting of stimulated endothelial NO and donated NO responses but not to non-NO vasodilators or vasoconstrictors.     

Angiotensin converting enzyme gene deletion allele is independently and strongly associated with coronary atherosclerosis and myocardial infarction.

OBJECTIVE--To investigate the association of the three angiotensin converting enzyme (ACE) genotypes, DD, ID, and II, with the occurrence or absence of coronary atherosclerosis and with myocardial infarction and hypertension. DESIGN--Cohort analysis study. SETTING--North-Italy reference centre. SUBJECTS--388 white Italian patients (281 males; mean age 60.7 (SD 12.5) years) with proven coronary atherosclerosis (n = 255) or with angiographically normal coronary arteries (n = 133). A further group of 290 healthy blood donors was tested for allele frequency comparison. INTERVENTIONS--ACE/ID polymorphism was analysed with polymerase chain reaction on DNA from white blood cells. MAIN OUTCOME MEASURES--Coronary atherosclerosis, myocardial infarction, hypertension. RESULTS--The D and I allele frequencies were respectively 0.63 and 0.37 in the overall healthy blood donor group and 0.66 and 0.34 in the overall study group. In the latter, univariate analysis showed (1) that coronary atherosclerosis (255 patients) was associated with the deletion allele, with an odds ratio (OR) of 5.78 for DD/II, P < 0.001, and 2.39 for ID/II, P = 0.006; and (2) that myocardial infarction (154 patients) was associated with the DD genotype (OR DD/II = 2.56, P = 0.007), but not with the ID genotype (OR DD/II = 1.96, P = 0.056). Finally, hypertension proved to be unrelated with the ACE genotype. The distribution between the three genotypes of known risk factors for coronary artery disease was similar. Logistic regression modelling, performed to test the association of the selected risk factors simultaneously with coronary atherosclerosis and myocardial infarction, showed that the deletion allele (whether DD or ID) was the strongest risk factor for atherosclerosis, and that the D allele was significantly associated with the risk of infarction (although to a lesser extent than with coronary atherosclerosis). CONCLUSION--ACE deletion polymorphism is strongly and independently associated with coronary atherosclerosis and, to a lesser extent, with myocardial infarction. As such, the results are analogous to what has already been reported in French white, Japanese, and Welsh coronary patients.     

The deletion genotype of the angiotensin I-converting enzyme is associated with an increased vascular reactivity in vivo and in vitro.

OBJECTIVES: To define a link between the deletion genotype (DD) and vascular reactivity, we studied in vivo and in vitro phenylephrine (PE)-induced tone and the effect of angiotensin II (AII) at physiological (subthreshold) concentrations on PE-induced tone. BACKGROUND: The deletion allele (D) of the angiotensin I-converting enzyme (ACE) has been associated with a higher circulating and cellular ACE activity and possibly with some cardiovascular diseases. METHODS: During cardiac surgery PE-induced contraction was studied in patients with excessive hypotension. In parallel, excess material of internal mammary artery, isolated from patients operated for bypass surgery, was mounted in an organ chamber, in vitro, for isometric vascular wall force measurement. RESULTS: In patients under extracorporeal circulation, PE (25 to 150 microg) induced higher contractions in patients with the DD genotype (e.g., with PE 75 microg: 20.3 +/- 2.9 vs. 11.5 +/- 2.5 mm Hg/ml per min, DD vs. II/ID, n = 15 vs. 30, p < 0.03). In the mammary artery, in vitro, contractions to PE (0.1 to 100 micromol/liter) or AII (1 or 100 nmol/liter) were not affected by the genotype. Angiotensin II (10 pmol/liter) significantly potentiated PE (1 micromol/liter)-induced contraction in both groups. Potentiation of PE-induced tone by AII was significantly higher in the DD than in the II/ID group. CONCLUSIONS: The DD genotype was associated with an increased reactivity to PE in vivo and potentiating effect of exogenous AII in vitro. The higher response to PE in vivo might reflect a higher potentiation by endogenous AII. These data should be considered to understand possible link(s) between cardiovascular disorders and the ACE gene polymorphism.     

Exclusion of the ACE D/I gene polymorphism as a determinant of endothelial dysfunction

A deletion/insertion (D/I) polymorphism within the ACE gene may increase the risk of cardiovascular events through still unknown mechanisms. The latter may involve increased angiotensin II-induced NO breakdown and/or reduced agonist-mediated NO release. We therefore investigated whether the D allele of the ACE gene affects endothelium-dependent vasodilatation in mild-to-moderate primary hypertensive patients and healthy normotensive subjects. We compared in a cross-sectional study the forearm blood flow response of the 3 D/I genotypes with 5 incrementally increasing doses of the endothelium-dependent vasodilator acetylcholine (0.15, 0.45, 1.5, 4.5, and 15 microg. 100 mL(-1). min(-1)) in 142 subjects: 103 mild-to-moderate uncomplicated primary hypertensives (49.3+/-9.1 years old, 152+/-11/99+/-5 mm Hg) and 39 normotensives (44.6+/-15.3 years old, 122+/-12/78+/-6 mm Hg). We also assessed the endothelium-independent vasodilatation in the forearm, as blood flow response to 3 incrementally increasing doses of sodium nitroprusside (1, 2, and 4 microg. 100 mL(-1). min(-1)). The overall genotype distribution was II, n=10; ID, n=70; and DD, n=62. It did not differ significantly between primary hypertensives and normotensives. A significant blunting of endothelium-dependent vasodilatation in primary hypertensive patients compared with normotensive subjects (P:<0.001) was found. No effect of the DI genotype on endothelium-dependent and -independent vasodilatation was detected. Thus, these results obtained in a relatively large population do not support the contention that the D allele is associated with a blunting of either stimulated endothelial NO or donated NO responses in both mild-to-moderate primary hypertensive patients and normotensive subjects.     

ACE基因I/D多态性与冠状动脉支架内再狭窄相关性研究

目的研究冠状动脉内行药物洗脱支架置入术患者,术后支架内再狭窄发生情况与ACE基因I/D多态性的关系。方法所有患者行冠状动脉造影检查,PCR方法测定ACE基因型。根据血管造影结果分为再狭窄组（病变狭窄≥50%）和无再狭窄组（病变狭窄〈50%）。采用SPSS18.0软件比较再狭窄组与无再狭窄组的临床基本特征、冠脉造影资料,以及与ACE基因型的关系。结果此次研究共纳入396名行药物洗脱支架置入术的冠心病患者,支架内再狭窄发生40例,再狭窄率为10.1%。再狭窄组与无再狭窄组的临床基本资料、冠脉造影资料均无显著性差异（P〉0.05）。再狭窄组的ACEDD基因型35.56%、ACEDI基因型16.39%、ACEII基因型3.85%。再狭窄组与ACE基因I/D多态性具有相关性（P〈0.001）。结论冠状动脉内行药物洗脱支架置入术患者术后支架再狭窄发生与ACEDD基因型具有显著相关性。     

Lower mortality in patients with the DD genotype of the angiotensin-converting enzyme gene after acute myocardial infarction.

OBJECTIVE: The angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been associated with different serum ACE concentrations and cardiac ACE activity. We assessed whether the ACE gene I/D polymorphism influenced cardiac mortality in Japanese patients with acute myocardial infarction. METHODS AND RESULTS: The ACE gene I/D polymorphism was determined in 441 consecutive patients with a first myocardial infarction.There were 69 patients (16%) with the DD genotype, 194 patients (44%) with the ID genotype, and 178 patients (40%) with the II genotype. During a mean follow-up of 9.4 months, there were 49 cardiac deaths (DD, n = 4; ID, n = 26; II, n = 19).The DD genotype was significantly associated with a lower mortality than the other genotypes (p = 0.0363) by Cox regression analysis adjusted for age, sex, site of myocardial infarction, Killip functional class, reperfusion therapy during acute phase, ACE inhibitor use, and beta-blocker use. CONCLUSIONS: In a selected cohort of Japanese patients, the DD genotype was associated with a significantly lower cardiac mortality after a first myocardial infarction.     

Angiotensin-converting enzyme gene polymorphism in a cohort of coronary angiography patients

An association between a polymorphism of the angiotensin-converting enzyme (ACE) gene and myocardial infarction (MI) in men has been previously reported. The present study examines the association between ACE genotype, atherosclerosis, MI, hypertension and other cardiovascular risk factors in Caucasian men (n=576) and women (n=124) who have undergone coronary angiography. Gene frequencies are also reported for African-American men (n=56). Genotype determination was based on the presence (allele I) or absence (allele D) of a 287 nucleotide Alu sequence in intron 16 of the ACE gene. Genotype frequencies for DD, ID and II were: 30.9, 47.7, 21.4% for Caucasian men; 28.2, 48.4, 23.4% for Caucasian women; and 30.4, 46.4, 23.2% for African-American men. There were no statistically significant associations between ACE genotype and number of plaques (> or =10% obstruction), lipid variables, or body mass index (BMI) for Caucasian men. Caucasian women with the DD genotype had on average fewer plaques, but this was accounted for by their younger ages. In Caucasian males, the DD genotype independently contributed to the presence of hypertension (odds ratio=1.8, 95% CI 1.1-2.9) after adjusting for age and BMI. In Caucasian males with total cholesterol levels less than 200 mg/dl (n=237), the DD (odds ratio=2.5, 95% CI 1.2-5.4) and ID genotypes (odds ratio=2.2, 95% CI 1.1-4.4) were associated with a history of MI.     

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.     

Association of left ventricular systolic performance and cavity size with angiotensin-converting enzyme genotype in idiopathic dilated cardiomyopathy

The insertion-deletion (ID) polymorphism of the angiotensin-converting enzyme (ACE) gene is a marker linked to differences in plasma and cardiac ACE activity as well as to an increased mortality in patients with idiopathic heart failure. We examined the possibility that ACE gene ID variants are associated with differences in left ventricular (LV) systolic performance or internal LV dimensions in a high-risk cohort of patients with idiopathic dilated cardiomyopathy (IDC). The ACE genotype was determined in 171 patients selected with IDC in New York Heart Association functional class II to III heart failure and with a LV ejection fraction of < or = 40%. Left ventricular performance and dimensions were assessed using echocardiography (n = 161) and radionuclide ventriculography (n = 169). The frequency of ACE gene ID alleles was not different in the study versus non-age-matched (n = 171; odds ratio 0.94) and age-matched (n = 106, odds ratio 0.88) control groups. Ejection fraction was found to be worse in patients with the DD genotype (echocardiography, DD = 23.5 +/- 0.70, ID + II = 26.8 +/- 0.8, p = 0.009; ventriculography, DD = 21.7 +/- 0.9, ID + II = 25.3 +/- 0.8, p = 0.003). LV end-systolic and end-diastolic diameters were increased in patients with the DD genotype. Multifactor regression analysis showed the ACE genotype to be an independent predictor of both ejection fraction (echocardiography, p <0.02; ventriculography, p <0.03) and end-diastolic diameter (p <0.02). In conclusion, the results of this study indicate that the DD genotype of the ACE gene is independently associated with both a reduced LV systolic performance and an increased LV cavity size in patients with IDC.     

Insertion/Deletion Polymorphism of the Angiotensin I-Converting Enzyme Gene Is Associated With Coronary Artery Plaque Calcification As Assessed by Intravascular Ultrasound

Objectives. We evaluated the influence of the insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene on coronary plaque morphology and calcification in patients with angiographically documented coronary artery disease (CAD).Background. The ACE I/D polymorphism has been associated with an increased risk of myocardial infarction in patients with the DD genotype but not with the presence of native CAD.Methods. We studied 146 patients undergoing percutaneous transluminal coronary angioplasty for stable angina pectoris by means of preinterventional intravascular ultrasound (IVUS). Qualitative and quantitative criteria were used to classify the target lesions as poorly or highly echoreflective or as calcified. Genomic deoxyribonucleic acid was analyzed by polymerase chain reaction (PCR) to identify the I/D polymorphism, with a second insertion-specific PCR in DD genotypes to prevent mistyping.Results. The ACE genotype groups (DD 46, ID 68, II 32) were well matched for the basic characteristics. Patients with the DD genotype had significantly more calcified lesions (DD 80%, ID 57%, II 66%; unadjusted odds ratio [OR] 2.88, 95% confidence interval [CI] 1.30 to 6.92, p = 0.008) and more calcifications >180° of the vessel circumference (DD 22%, ID 10%, II 6%; OR 2.80, 95% CI 1.05 to 7.63, p = 0.03). The prevalence of myocardial infarction was not significantly associated with coronary calcification (OR 1.44, 95% CI 0.72 to 2.88, p = 0.31).Conclusions. Patients with CAD and the ACE DD genotype have a significantly higher incidence and greater extent of coronary lesion calcification, as determined by IVUS. This finding indicates that the ACE I/D gene polymorphism is related to the development or progression of atherosclerotic plaque calcification.     

Coronary endothelium-dependent and independent vasomotor responses in patients with hypertrophic cardiomyopathy.

It is well known that coronary flow reserve (CFR) is decreased in patients with hypertrophic cardiomyopathy (HCM), but it is unclear whether coronary endothelial function is impaired. Coronary endothelial function and CFR in the coronary macro- and microcirculation was evaluated in 14 patients with HCM and 11 control subjects. Acetylcholine (ACh), bradykinin (BK) and papaverine were infused into the left coronary artery. Coronary cross-sectional area was determined by quantitative coronary angiography and coronary blood flow (CBF) was determined by the product of the coronary cross-sectional area and CBF velocity measured by an intracoronary Doppler guidewire. Acetylcholine at 100 microg induced diffuse coronary spasms of the left anterior descending coronary arteries in 3 of the patients with HCM. The changes in the diameter of the left anterior descending coronary artery and the increases in CBF induced by BK (0.2, 0.6, and 2.0 microg/min) did not differ between the 2 groups. CFR was lower in the HCM group than in the control group (p<0.01). Moreover, the ratio of BK-induced CBF increase to papaverine-induced CBF increase was comparable between the 2 groups. Endothelium-dependent vasodilation of the epicardial and resistance coronary arteries induced by BK was preserved despite the decreased CFR in patients with HCM.     

Renal changes on hyperglycemia and angiotensin-converting enzyme in type 1 diabetes

Hyperglycemia causes capillary vasodilation and high glomerular capillary hydraulic pressure, which lead to glomerulosclerosis and hypertension in type 1 diabetic subjects. The insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene can modulate risk of nephropathy due to hyperglycemia, and the II genotype (producing low plasma ACE concentrations and probably reduced renal angiotensin II generation and kinin inactivation) may protect against diabetic nephropathy. We tested the possible interaction between ACE I/D polymorphism and uncontrolled type 1 diabetes by measuring glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) during normoglycemia ( approximately 5 mmol/L) and hyperglycemia ( approximately 15 mmol/L) in 9 normoalbuminuric, normotensive type 1 diabetic subjects with the II genotype and 18 matched controls with the ID or DD genotype. Baseline GFR (145+/-22 mL/min per 1.73 m2) and ERPF (636+/-69 mL/min per 1.73 m2) of II subjects declined by 8+/-10% and 10+/-9%, respectively, during hyperglycemia; whereas baseline GFR (138+/-16 mL/min per 1.73 m2) and ERPF (607+/-93 mL/min per 1.73 m2) increased by 4+/-7% and 6+/-11%, respectively, in ID and DD subjects (II versus ID or DD subjects: P=0.0007 and P=0.0005, for GFR and ERPF, respectively). The changes in renal hemodynamics of subjects carrying 1 or 2 D alleles were compatible, with a mainly preglomerular vasodilation induced by hyperglycemia, proportional to plasma ACE concentration (P=0.024); this was not observed in subjects with the II genotype. Thus, type 1 diabetic individuals with the II genotype are resistant to glomerular changes induced by hyperglycemia, providing a basis for their reduced risk of nephropathy.     

Effects of angiotensin-converting enzyme gene polymorphism on the left-ventricular function and mass in patients with acromegaly

In this study we have investigated the contribution of the ACE genotype to the development of left-ventricular hypertrophy (LVH) and systolic and diastolic dysfunctions in acromegalic patients. The study group consisted of 30 acromegalic patients (21 women and 9 men, age: 37.9 +/- 10.8 years, disease duration: 9.0 +/- 6.9 years). The distribution of the DD, ID and II genotypes was 40.0 (n = 12), 46.6 (n = 14) and 13.3% (n = 4), respectively, being similar to frequencies observed in a healthy population. Plasma ACE levels were 55.0 +/- 12.0 (45-84), 28.7 +/- 15.7 (8-58) and 24.5 +/- 12.0 (16-33) U/I in patients with the DD, ID and II genotype, respectively. The mean serum ACE activity in the DD genotype was significantly higher than in the heterozygous group (p < 0.0001). Serum ACE activity showed a significant negative association with the mean growth hormone level (r = -0.52, p = 0.007). The LV early diastolic flow velocity/LV presystolic flow velocity (E/A) ratios were 1.2 +/- 0.4 for the DD genotype, 1.3 +/- 0.3 for the ID genotype and 0.7 +/- 0.1 for the II genotype. The E/A ratio was considerably lower in acromegalic patients with the II genotype compared to the other genotypes (p = 0.03). The LV mass index (LVMI) values were 131.5 +/- 4.2 g/m2 for the DD genotype, 141.7 +/- 50.3 g/m2 for the ID genotype and 159.6 +/- 48.2 g/m2 for the II genotype. However, there was no significant difference in LVMI among allelic groups. All other indices of systolic and diastolic function were not statistically different in the acromegalic patients. The present data fail to support a role of ACE gene polymorphism in determining LVH in acromegalic patients. However, the I allele may prove as a useful marker predicting the development of diastolic dysfunction in acromegalic patients.     

Pharmacogenetic interactions between angiotensin-converting enzyme inhibitor therapy and the angiotensin-converting enzyme deletion polymorphism in patients with congestive heart failure

OBJECTIVES: We evaluated the interaction of angiotensin-converting enzyme (ACE) inhibitor therapy with the effect of the ACE D/I polymorphism on heart failure survival. BACKGROUND: The ACE deletion allele, ACE-D, is associated with increased ACE activity. The utilization of ACE genotyping to predict the impact of ACE inhibitor dose has not been previously evaluated. METHODS: We prospectively studied 479 subjects with systolic dysfunction (left ventricular ejection fraction 0.25 +/- 0.08). Subjects were divided on the basis of ACE inhibitor therapy into low dose (50%, n = 201), or those receiving angiotensin receptor antagonists (n = 51). Patients were genotyped for the ACE D/I polymorphism, followed to the end point of death or cardiac transplantation, and transplant-free survival compared by genotype. RESULTS: The ACE-D allele was associated with an increased risk of events (p = 0.026). In analysis by ACE inhibitor dose, this effect was primarily in the low-dose group (1-year percent event-free survival: II/ID/DD = 86/77/71,2-year = 79/66/59, p = 0.032). In the standard-dose group, the impact was markedly diminished (1-year: II/ID/DD = 91/81/80, 2-year: 77/70/71, p = 0.64). The impact of beta-blockers and high dose ACE inhibitors was greatest in subjects with the ACE DD genotype (p = 0.001) and was less apparent with the II and ID genotypes (p = 0.38). CONCLUSIONS: Higher doses of ACE inhibitors diminished the impact of the ACE-D allele, and the benefits of beta-blockers and high-dose ACE inhibitors appeared maximal for DD patients. Determination of ACE genotype may help target therapy for patients with heart failure.