Echogenic carotid plaques are associated with aortic arterial stiffness in subjects with subclinical carotid atherosclerosis

A better understanding of the interrelationships between the structure and function of the large arteries would lead to optimize cardiovascular disease prevention strategies. In this study, we investigated the relationships of aortic arterial stiffness assessed by carotid-femoral pulse-wave velocity (PWV), with carotid plaque echogenicity assessed by B-mode ultrasound. We analyzed 561 subjects (without coronary heart disease or stroke) who were volunteers for free health examinations (age, 58.3+/-10.8 years; 32.6% women). Extracranial carotid plaque echogenicity was graded from 1 (plaque appearing black or almost black) to 4 (plaque appearing white or almost white) according to the Gray-Weale classification. Plaques of grades 1 and 2 were defined as echolucent plaques, and plaques of grades 3 and 4 were defined as echogenic plaques. Fifty-one subjects (9.1%) had echolucent carotid plaques, 109 (19.4%) had echogenic plaques, and 401 (71.5%) had no plaques. Subjects with echogenic plaques had higher PWV mean (12.9+/-2.8 m/s) compared with those without plaques (11.1+/-2.3 m/s, P<0.001) and compared with those with echolucent plaques (11.3+/-2.3 m/s, P<0.01). The PWV means in subjects without plaques and those with echolucent plaques were similar and not statistically different (P=0.55). When multivariate adjustment for major known cardiovascular risk factors was performed, these results were not markedly modified. Similar patterns of results were also observed in many subgroups according to age, gender, and hypertensive status. This study provides the first evidence that echogenic but not echolucent carotid plaques are associated with aortic arterial stiffness. This association applies to individuals with normal blood pressure and those with elevated blood pressure. Assessment of the joint and interaction effects of plaque morphology and arterial stiffness on the occurrence of cardiovascular events would permit a better identification of high-risk subjects.     

The role of carotid plaque vulnerability and inflammation in the pathogenesis of acute ischemic stroke

BACKGROUND: Increasing evidences show that disruption of carotid plaque followed by arterio-arterial thromboembolism is an important mechanism in the generation of ischemic stroke. Inflammatory mechanisms play a key role in transforming structurally vulnerable plaques into functionally unstable ones. The purpose of the present study is to evaluate the roles of carotid plaque vulnerability and inflammation in the pathogenesis of acute ischemic stroke. METHODS: Fifty-two patients with acute ischemic stroke affecting the anterior circulation (stroke group) and 44 with asymptomatic carotid stenosis (asymptomatic group) were investigated. Duplex ultrasonography was used to evaluate the characteristics of carotid plaque and grading the degree of carotid stenosis. Plaque echogenicity was assessed as echolucent, predominantly echolucent, predominantly echogenic, or echogenic. Plaque surface was classified as smooth, irregular, or ulcerated. All subjects had duplex-determined 50% to 99% carotid stenosis. Serum levels of matrix metalloproteinase-9 (MMP-9), tissue inhibitors of metalloproteinases (TIMP-1), soluble CD40 ligand (sCD40L) and high-sensitivity C-reactive protein (hsCRP) were measured. RESULTS: Plaques in the stroke group were echolucent or predominantly echolucent, whereas those of the asymptomatic group were predominantly echogenic or echogenic plaques (P<0.05). Irregular and ulcerated plaques were frequently found in stroke patients, while smooth plaques were frequently detected in asymptomatic patients (P<0.05). Serum levels of MMP-9, sCD40L, hsCRP were higher in stroke than in asymptomatic patients. By contrast, serum TIMP-1 levels were significantly higher in the asymptomatic than in the stroke group. CONCLUSIONS: The results suggest that inflammation plays a crucial role in carotid plaque vulnerability and, together with carotid plaque morphology, in the pathogenesis of acute ischemic stroke.     

Angiotensin-converting enzyme gene polymorphism and common carotid stiffness. The Rotterdam study

The insertion/deletion (I/D) polymorphism of the ACE gene may be involved in structural arterial changes. Aim of the present study was to assess the relationship between the ACE I/D gene and vessel wall stiffness among older adults. The study was conducted within the Rotterdam study, a population-based cohort study including subjects aged 55 years and older. The II, ID and DD genotypes of the ACE gene were determined in all subjects. The distensibility coefficient (10(-3)/kPa) of the carotid artery and the carotid-femoral pulse wave velocity were measured during the third phase of the Rotterdam study (1997-1999) and were used as measure of arterial stiffness. Data on both carotid stiffness and the ACE genotype were available for 3001 participants. After adjustment for age and gender, subjects with the ID and DD genotype had higher carotid stiffness compared to subjects with II genotype (distensibility coefficient (10(-3)/kPa) 10.24 (95% CI, 10.06-10.43), 10.27 (95% CI, 10.02-10.52), 10.65 (95% CI, 10.37-10.93), respectively (ID versus II genotype, P = 0.017), (DD versus II genotype, P = 0.037)). In stratified analyses, the association was strongest in subjects younger than 70 years. No difference was seen for pulse wave velocity among genotypes. In conclusion, the results of this population-based study show that the ACE ID/DD genotypes are associated with higher common carotid stiffness.     

Serum osteoprotegerin is inversely associated with carotid plaque echogenicity in humans

Osteoprotegerin (OPG) is a member of the tumour necrosis factor superfamily involved in the regulation of bone metabolism and vascular calcification. High serum values of OPG are associated with cardiovascular disease in humans. The purpose was to investigate serum OPG levels in subclinical carotid atherosclerosis and the relation between OPG levels and plaque morphology. OPG levels were compared in 29 persons with echogenic carotid plaques, 30 persons with echolucent plaques and 41 persons without carotid plaques, all recruited from a population health study. Computerized assessment of plaque echogenicity was done by use of the gray scale median (GSM). Participants with echogenic carotid plaques had lower serum OPG level (1.23 ng/ml; 1.02-1.48) (geometric mean; 95% CI) than persons with echolucent plaques (1.76 ng/ml; 1.46-2.14) and those without plaques (1.89 ng/ml; 1.60-2.21). OPG and PTH were independently related to GSM. A significant trend for decrease in GSM across quartiles of OPG was found (p=0.003) which remained significant even after adjustment for PTH and smoking. The present study demonstrates lower serum OPG levels in persons with subclinical echogenic carotid plaques and identified an inverse relation between serum OPG and plaque echogenicity. The findings support the concept that OPG may play an important role in arterial calcification.     

The DD genotype of angiotensin converting enzyme polymorphism is a risk factor for coronary artery disease and coronary stent restenosis in Japanese patients

Stent implantation has decreased the incidence of restenosis after coronary intervention, but has not eliminated it. The contribution of the angiotensin-converting enzyme (ACE) genotype to the development of coronary artery disease and restenosis after coronary stenting was investigated in 67 Japanese patients in whom 103 lesions in which stents had been successfully implanted were assessed by quantitative coronary angiography, before, immediately after coronary stenting, and during follow-up. The distribution of the patients with the DD, ID, and II genotypes was 13%, 54%, and 33%, respectively. The prevalence of multivessel disease in the DD genotype was significantly higher (DD genotype: 78%; ID genotype: 58%; II genotype: 27%, chi2=8.13, p=0.016) and the late loss in the DD genotype (1.43+/-0.96 mm) was significantly greater (ID genotype: 0.78+/-0.98 mm and II genotype: 0.79+/-0.88 mm, p<0.05 vs DD genotype). However, there was no significant difference in the restenosis rate among the 3 genotypes. The present study in Japanese patients indicates that the DD genotype is associated with more extensive coronary artery disease and progression of the inward remodeling within the stented lesion, which is primarily caused by neointimal hyperplasia.     

An interaction between systolic blood pressure and angiotensin-converting enzyme gene polymorphism on carotid atherosclerosis.

The insertion/deletion (I/D) polymorphism of the human angiotensin-converting enzyme (ACE) gene is a major determinant of circulating ACE activity, with the D allele being associated with higher ACE levels than the I allele. Thus, chronic exposure to high levels of circulating and tissue ACE may well predispose to vascular wall thickening and atherosclerosis. However, the effect of the ACE gene on carotid atherosclerosis remains controversial. We investigated the association between ACE gene I/D polymorphism and risk factor-dependent augmentation of carotid arterial remodeling in subjects with several risk factors for atherosclerosis. We evaluated sclerotic lesions of the common carotid artery with intima-media thickness (IMT) by ultrasonography in 184 patients (mean age +/- SD, 67 +/- 14 years old) and studied whether any risk factor-gene interactions were associated with carotid atherosclerosis. Out of the 184 subjects, 71 had the ACE II genotype, 87 the ID genotype and 26 the DD genotype. There was no significant difference in IMT among the three ACE genotypes. In total subjects, multiple regression analysis showed that age, total-cholesterol (T-C), and HDL-cholesterol (HDL-C) were significantly associated with IMT. However, the association between risk factors and IMT was genotype-specific. Systolic blood pressure (SBP) and HDL-C were significantly associated with IMT in ACE D carriers (DD+ID), but not in subjects with the ACE II genotype. Similarly, T-C was significantly associated with IMT only in subjects with the ACE II genotype. A general linear model of the interaction between the ACE genotype and the conventional risk factors showed that the SBP-ACE genotype interaction were significantly associated with IMT (F = 7.915; p = 0.005). This finding further supports the idea that analysis of risk factor-gene interaction could be a useful tool for deriving specific predictive information about the development of atherosclerosis.     

Multiple risk factor intervention reduces cardiovascular risk in hypertensive patients with echolucent plaques in the carotid artery

OBJECTIVE: In a previously published randomized 6-year study we observed that multiple risk factor intervention reduced cardiovascular risk in high-risk hypertensive men, and that this effect was confined to patients with carotid artery plaques. Hypothetically, the underlying mechanism might have been a stabilization of echolucent, instable, rupture-prone plaques. The aim of the present study was to examine plaque characteristics by B-mode ultrasound in the previous intervention study, and also to investigate the relationship between plaque characteristics at baseline and cardiovascular events during the 6-year follow-up in the two randomization groups. METHODS: High resolution B-mode ultrasound was used to characterize plaque echogenicity in four subgroups - dominantly echolucent, substantially echolucent, dominantly echogenic, and uniformly echogenic. RESULTS: In the usual care group 17 of 32 (53%) patients with echolucent plaques at baseline suffered from a combined end-point (any death or nonfatal myocardial infarction or nonfatal stroke) during follow-up compared with seven of 28 (25%) patients in the intervention group (P = 0.036). The corresponding numbers in patients with echogenic plaques were n = 4/13 (31%) and n = 4/17 (24%), respectively (NS). In the usual care group 11 of 33 (33%) patients with no plaques suffered from a combined end-point during follow-up compared with 11 of 30 (37%) in the intervention group. CONCLUSION: Our data indicate that the beneficial effect of the multiple risk intervention programme was confined to those patients with echolucent plaques. The data have to be confirmed with a large-scale trial.     

Association of the angiotensin-converting enzyme gene polymorphism with chronic heart failure in Chinese Han patients

BACKGROUND: An insertion/deletion (I/D) polymorphism is present in the 16th intron of the angiotensin-converting enzyme (ACE) gene and is associated with serum and tissue ACE level. Some studies have shown that the DD genotype is associated with some cardiovascular diseases; while ACE polymorphism's effect on chronic heart failure (CHF) remains uncertain. AIM: To investigate the association of the ACE gene I/D polymorphism with CHF in the Chinese Han population. METHODS: The genotype was determined by polymerase chain reaction in 102 normal controls and in 79 patients with CHF. Plasma angiotensin (Ang) levels were assessed by radio-immunity assay. Left ventricular end-diastolic diameters (LVDD) and left ventricular ejection fractions were assessed by echocardiography. RESULTS: The ACE gene polymorphism distribution was similar in patients and control subjects. However, ACE gene DD polymorphism was associated with a more severe condition, greater LVDD [mm: DD: 71+/-7, ID: 62+/-5, II: 60+/-5, P<0.001 DD vs. ID, P<0.001 DD vs. II] and higher plasma Ang II level [pg/ml DD: 92+/-19, ID: 79+/-21, II: 65+/-17 P<0.05 DD vs. ID, P<0.001 DD vs. II]. CONCLUSION: In Chinese Han patients with CHF, ACE gene DD polymorphism might be a marker of a more severe condition, and a higher level of activation of the renin-angiotensin system.     

Circulating oxidized low-density lipoprotein is associated with echolucent plaques in the femoral artery independently of hsCRP in 61-year-old men

OBJECTIVES: The aim of the study was to test the hypothesis that circulating markers of inflammation (high-sensitive C-reactive protein, hsCRP) and oxidative modification of lipids (oxidized low-density lipoprotein, oxLDL) were associated with the occurrence of echolucent rather than echogenic femoral artery plaques in a cross-sectional population based cohort of 513, 61-year-old men. BACKGROUND: The relationships between circulating oxLDL, hsCRP and the occurrence of echolucent plaques in the femoral artery have not previously been investigated. METHODS: The levels of circulating oxLDL and hsCRP were determined in plasma by ELISA. Plaque occurrence, size and echogenicity were measured by B-mode ultrasound in the right femoral artery. Assessment of plaque echogenicity was based on the classification (grades 1-4) proposed by Gray-Weale et al. RESULTS: A higher frequency of echolucent femoral plaques was observed in subjects with the metabolic syndrome and current smokers (p=0.01 and p<0.001, respectively) as well as with increasing levels of oxLDL and hsCRP (p=0.002 and p=0.005, respectively). In a multiple logistic regression analysis oxLDL and current smokers turned out to be independent associated with the presence of echolucent femoral artery plaques. CONCLUSIONS: The results of the present study support our hypothesis that circulating oxLDL is a marker of an unstable echolucent plaque phenotype in the femoral artery in man.     

Risk for transient ischemic attacks is mainly determined by intima-media thickness and carotid plaque echogenicity

BACKGROUND: Stenosis severity, plaque morphology, and intima-media thickness (IMT), all have been found to provide prognostic information in patients with asymptomatic carotid artery disease. However, limited data exist on the association between these parameters and the risk for transient ischemic attack (TIA). METHODS: We compared the ultrasonographic characteristics of 88 consecutive patients with first TIA without known cardioembolic source with those of 176 propensity-matched asymptomatic control subjects. RESULTS: IMT was higher in TIA patients compared to control subjects (0.74+/-0.14 mm versus 0.68+/-0.13 mm, p=0.001). Plaques were found in 70.5% of patients and 64.8% of controls (p=0.407). Compared with controls, TIA patients demonstrated more frequently predominantly echolucent lesions (77.4% versus 56.1%, p=0.005) and high-grade carotid stenoses (21.0% versus 9.6%, p=0.042). TIA patients with low-to-moderate grade (<70%) lesions exhibited higher IMT and more prevalent echolucent morphology in comparison with their control counterparts. No significant differences were observed between groups regarding high-grade lesions. In multivariate models, IMT and plaque echogenicity, but not stenosis severity, emerged as independent determinants of risk. CONCLUSIONS: Risk for TIA is primarily associated with IMT and plaque echogenicity, especially in the absence of high-grade lesions. Stenosis severity appears to be of limited prognostic value.     

The ACE/DD genotype is associated with the extent of exercise-induced left ventricular growth in endurance athletes

OBJECTIVES: We studied the impact of the angiotensin-converting enzyme (ACE)/DD genotype on morphologic and functional cardiac changes in adult endurance athletes. BACKGROUND: Trained athletes usually develop adaptive left ventricular hypertrophy (LVH), and ACE gene polymorphisms may regulate myocardial growth. However, little is known about the impact of the ACE/DD genotype and D allele dose on the cardiac changes in adult endurance athletes. METHODS; Echocardiographic studies (including tissue Doppler) were performed in 61 male endurance athletes ranging in age from 25 to 40 years, with a similar period of training (15.6 +/- 4 h/week for 12.6 +/- 5.7 years). The ACE genotype (insertion [I] or deletion [D] alleles) was ascertained by polymerase chain reaction (DD = 27, ID = 31, and II = 3). Athletes with the DD genotype were compared with their ID counterparts. RESULTS: The DD genotype was associated with a higher left ventricular mass index (LVMI) than the ID genotype (162.6 +/- 36.5 g/m(2) vs. 141.6 +/- 34 g/m(2), p = 0.031), regardless of other confounder variables. As a result, 70.4% of DD athletes and only 42% of ID athletes met the criteria for LVH (p = 0.037). Although systolic and early diastolic myocardial velocities were similar in DD and ID subjects, a more prolonged E-wave deceleration time (DT) was observed in DD as compared with ID athletes, after adjusting for other biologic variables (210 +/- 48 ms vs. 174 +/- 36 ms, respectively; p = 0.008). Finally, a positive association between DT and myocardial systolic peak velocity (medial and lateral peak S(m)) was only observed in DD athletes (p = 0.013, r = 0.481). CONCLUSIONS: The ACE/DD genotype is associated with the extent of exercise-induced LVH in endurance athletes, regardless of other known biologic factors.     

Relationship between polymorphism of the angiotensin-converting enzyme gene and the response to angiotensin-converting enzyme inhibition in hypertensive patients.

The aim of this study was to investigate the relationship between polymorphism of the anglotensin-converting enzyme (ACE) gene and the blood pressure response to ACE inhibition in a hypertensive cohort. Imidapril (5-10 mg/day) or benazepril (10-20 mg/day) was administered for 6 weeks to 517 essential hypertensives. ACE gene polymorphism was examined by the polymerase chain reaction (PCR) method and the patients were classified as having the 190-bp deletion homozygous (DD) genotype, the 490-bp insertion homozygous (II) genotype, or the 490-bp insertion, 190-bp deletion heterozygous (ID) genotype. The achieved change in systolic and diastolic blood pressure (SBP and DBP) was analyzed for association with genotypes at the ACE gene locus. The DD genotype was observed in 132 patients (25.5%), the ID genotype in 255 patients (49.3%), and the II genotype in 130 patients (25.2%). The SBP reductions in the patients with the DD genotype, II genotype, and ID genotype were -14.5 +/- 12.7 mmHg, -14.3 +/- 13.1 mmHg and -14.0 +/- 12.2 mmHg, respectively (p = 0.94). The DBP reductions in the patients with the DD genotype, II genotype, and ID genotype were -8.7 +/- 7.4 mmHg, -8.7 +/- 7.7 mmHg and -8.5 +/- 6.7 mmHg, respectively (p = 0.96). There was no significant association between the ACE gene polymorphisms and the response to ACE inhibition. These results suggest that ACE genotype does not predict the blood pressure-lowering response to antihypertensive treatment with ACE inhibition.     

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.     

I/D gene polymorphism of the angiotensin-converting enzyme and left ventricular hypertrophy. Response to converting enzyme inhibitors

BACKGROUND: The present study was designed to assess whether the angiotensin-converting enzyme (ACE) gene I/D polymorphism influence the ACE inhibitors effect on the regression of left ventricular hypertrophy. METHODS: Sixty hypertensive subjects never treated by antihypertensive drugs, aged 46 +/- 11 years, were included in the study. Follow-up with ACE inhibitor treatment was 60 +/- 26 months. Genotypes for ACE I/D polymorphism (DD, ID or II) were determined by PCR. The left ventricular mass index (LVMI) was assessed by two-dimensional directed M-mode echocardiography. RESULTS: ACE genotype distribution was in agreement with the Hardy-Weinberg equilibrium: 21 patients had the DD genotype, 29 were ID, and 10 were II. At baseline, age, systolic arterial pressure and LVMI didn't differ on the basis of genotype. Body mass index was significantly higher in II than in ID and DD groups. Regression of LVMI with ACE inhibitor treatment was similar in the 3 genotypes (-8.9%, -0.6%, -12.1% in DD, ID and II groups respectively). In addition, decrease of systolic arterial pressure was identical in 3 groups. CONCLUSION: ACE gene I/D polymorphism seems not to influence regression of left ventricular hypertrophy by ACE inhibitors in essential hypertension.     

老年人动脉弹性与颈动脉斑块超声特征相关性研究

目的探讨老年人动脉弹性与颈动脉斑块不同超声分型的关系。方法选定北京军队干休所的721例老年人（年龄≥60岁）,填写调查表,行颈动脉超声多普勒检测颈总动脉内中膜厚度（IMT）、颈内外动脉及颈总动脉斑块情况,根据颈动脉斑块的不同回声强度,将颈动脉斑块分为硬斑组及软斑组,半定量估计颈动脉粥样硬化斑块等级。采用全自动动脉硬化测定仪（日本Colin公司生产VP-1000）同步记录左右侧臂踝脉搏波传导速度（PWV）作为反映大动脉弹性的指标。应用统计学方法探讨老年人动脉弹性与颈动脉斑块不同超声分型之间的关系。结果收缩压、PWV在硬斑组较软斑组明显升高,血总胆固醇、血甘油三酯在软斑块组明显增高,两组之间存在显著差异,而其他心血管病危险因素在两组间无差别。半定量法估计颈动脉斑块等级,PWV在硬斑组中随着斑块严重程度而增加,三组之间具有显著性差异,而软斑组未显示同样的差别。结论PWV与硬斑密切相关,提示动脉弹性减退与硬斑形成可能具有相似的病理发展过程。     

血管紧张素转换酶和醛固酮合成酶基因多态性与氢氯噻嗪降压疗效的关系

目的研究血管紧张素转换酶(ACE)基因I/D多态性和醛固酮合成酶(CYP11B2)基因-344T/C多态性与氢氯噻嗪降压疗效的关系。方法829例高血压病(EH)患者同时服用氢氯噻嗪12·5mg(1次/d),6周后资料完整的785例患者按不同ACE基因型和CYP11B2基因型分组,比较不同基因型和不同基因型组合间血压下降值有无差别。结果服用氢氯噻嗪6周后,ACE基因II、ID、DD型患者收缩压分别下降(5·1±14·8)mmHg(1mmHg=0·133kPa)、(4·8±16·3)mmHg和(9·4±15·7)mmHg,DD型患者下降值大于II、ID型患者,组间比较差异有统计学意义(P<0·00);CYP11B2基因TT、TC、CC型患者收缩压下降值分别为(5·8±16·2)mmHg、(5·5±14·9)mmHg和(7·6±16·1)mmHg,组间比较差异无统计学意义。DD+CC基因型患者收缩压下降值为(10·6±12·3)mmHg,高于其他基因型组合患者,但差异无统计学意义(P>0·05)。多因素分析结果表明DD基因型和治疗前醛固酮浓度是影响患者坐位收缩压下降的主要因素。结论ACE基因的DD型与氢氯噻嗪的降压疗效相关,CYP11B2基因CC型、DD+CC型患者对氢氯噻嗪的降压反应可能优于其他基因组合患者。     

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.     

Association between the angiotensin-converting enzyme gene polymorphisms and tissue oxygenation during exercise in patients with COPD

STUDY OBJECTIVES: We have recently determined that the angiotensin-converting enzyme (ACE) DD genotype might be associated with pulmonary hypertension during exercise in patients with COPD. Therefore, this study was designed to determine whether ACE gene polymorphisms adversely affect tissue oxygenation during exercise in patients with COPD. DESIGN: Cross-sectional analysis. SETTING: University hospital. PATIENTS: Thirty-nine patients (14 patients with II genotype, 12 patients with ID genotype, and 13 patients with DD genotype). INTERVENTIONS: All patients underwent right-heart catheterization and constant-load exercise testing for 5 min on an ergometer. Measurements and results: The ratio of the change in oxygen delivery (DO(2)) to the increase in oxygen consumption (O(2)) during exercise (DeltaDO(2)/DeltaO(2)) was significantly lower in patients with the DD genotype (1.5 +/- 0.2) than in those with the II genotype (1.9 +/- 0.3, p = 0.0006) and the ID genotype (1.7 +/- 0.2, p = 0.037). Mixed venous oxygen tension (PO(2)) after exercise in patients with the DD genotype (23.5 +/- 1.5 mm Hg) was also significantly lower than in patients with the II genotype (26.7 +/- 1.6 mm Hg, p = 0.0002) and the ID genotype (25.0 plus minus 2.0 mm Hg, p = 0.045). In addition, the change in plasma concentration of lactate during exercise (DeltaLactate) was significantly higher in patients with DD genotype (33.3 +/- 4.3 mmol/L) than in those with the II genotype (25.5 +/- 3.6 mmol/L, p = 0.0002) and the ID genotype (28.8 +/- 4.0 mmol/L, p = 0.029). The mean pulmonary arterial pressure after exercise was significantly correlated with DeltaDO(2)/DeltaO(2) (r = - 0.423, p = 0.0076) but not with PvO(2) after exercise and with DeltaLactate. CONCLUSIONS: The ACE DD genotype may be associated with an impairment in peripheral tissue oxygenation during exercise in patients with COPD.     

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.     

Genotype-specific association between circulating soluble cellular adhesion molecules and carotid intima-media thickness in community residents: J-SHIPP study. Shimanami Health Promoting Program.

Plasma levels of soluble forms of cellular adhesion molecules (CAMs) and their relationships with carotid intima-media thickness (IMT) were investigated in community residents. Plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured by ELISA in 200 community residents in Japan. Carotid IMT showed a weak but significant positive correlation with the plasma levels of both sICAM-1 (r=0.175, p=0.013) and sVCAM-1 (r=0.19, p=0.0075). Gene polymorphisms of angiotensin converting enzyme (ACE) insertion/deletion (I/D), angiotensinogen (AGT) M235T, angiotensin II type 1 receptor (AT1R) A1166C and apolipoprotein E (apoE) were determined for each subject. The plasma level of sVCAM-1 tended to be lower in subjects with the ACE DD genotype than in those with the ACE ID and II genotypes (373+/-94, 421+/-133, 443+/-135 ng/ml, respectively, p=0.056). However, there were no genotype-specific differences in the plasma levels of soluble forms of CAMs for the other genes examined. In a separate analysis, the plasma level of sICAM-1 was significantly associated with carotid IMT in ACE D carriers (ID + DD) (r=0.28, p=0.002), AGT M carriers (MT + MM) (r=0.32, p=0.0045), and subjects with apoE4 (r=0.35, p=0.036). In contrast, the plasma level of sVCAM-1 showed significant positive correlations with carotid IMT in subjects with the ACE II genotype (r=0.33, p=0.0027) or AGT TT genotype (r= 0.22, p=0.015), and subjects with apoE E2/E3 or E3/E3 (r=0.16, p=0.043). Stepwise regression analysis showed that plasma sVCAM-1 was independently associated with carotid IMT in subjects with the ACE II genotype or apoE4 genotype. Similarly, the plasma level of sICAM-1 was independently associated with carotid IMT in AGT M carriers. These findings suggest that genetic background could be involved in the association between plasma CAMs and atherosclerosis.