Angiotensin-converting enzyme I/D polymorphism and arterial wall thickness in a general population. The Vobarno Study

Case report: Umbilical vessel aneurysm thrombosis and factor V Leiden mutation leading to fetal demise

Complicated pregnancies are nowadays a major public health concern, with possible lethality or sequelae both for the mother and the fetus. Blood coagulation disorders (including antiphospholipid syndrome, factor V Leiden mutation and antithrombin deficiency) and hypertensive gestational disorders are very well-known contributors of complicated pregnancies with poor fetal outcome, such as intrauterine growth retardation (IUGR) and fetal demise. Less commonly, vascular malformations of the placenta can also potentially lead to serious complications such as IUGR and fetal death. These malformations include hypercoiled umbilical cord, umbilical cord knot, umbilical cord varix, umbilical cord arterial or venous aneurysm, and velamentous insertion of the umbilical cord potentially leading to Benckiser's hemorrhage. Here, we report the case of a 29-year-old Gravida 2 Para 0 mother with previous history of stillbirth and smoking, admitted to the obstetrics department for the absence of fetal movement at 38 weeks of amenorrhea (WA). First-trimester and second-trimester routine ultrasounds were otherwise normal. Ultrasound performed at 38 WA revealed a 83 × 66 × 54 mm cystic heterogenous mass at the umbilical cord insertion. After delivery, fetal and placental pathology as well as maternal blood testing were performed. Fetal pathology was otherwise normal, except for diffuse congestion and meconial overload suggesting acute fetal distress. Fetal karyotype was normal (46 XX). Placental pathology revealed an umbilical artery aneurysm (UAA) at the base of the insertion of the umbilical cord, lined with a CD34⁺ CD31⁺ endothelium. After dissection, the aneurysm was filled with hemorrhagic debris, indicating aneurysm thrombosis. Histopathology revealed associated maternal vascular malperfusion (MVM) and increased peri-villous fibrin (IPF). Maternal blood tests revealed heterozygous factor V Leiden mutation, without other associated auto-immune conditions (such as antiphospholipid syndrome). Umbilical artery aneurysms remain extremely rare findings in the placenta, with <20 reported cases. Umbilical artery aneurysms have tendency to be located at the base of the insertion of the placenta, and lead to fetal demise in more than 60% of cases, mainly due to aneurysmal thrombosis, hematoma, possible vascular compression and/or rupture. Umbilical vessel aneurysms can be associated with trisomy 18 or 13. In our case, the association of factor V Leiden mutation, a hypercoagulable state, with UAA could explain massive thrombosis of the aneurysmal lumen and sudden fetal demise. Further consideration of current guidelines for surveillance and management of UAA would allow appropriate planned delivery in maternal care settings.

Bradykinin-Potentiating Peptide-Paclitaxel Conjugate Directed at Ectopically Expressed Angiotensin-Converting Enzyme in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a heterogeneous subtype of breast cancer with poor prognosis. Here, we present a peptide-drug conjugate (PDC)-bradykinin-potentiating peptide-paclitaxel (BPP-PTX) conjugate-synthesized by conjugating BPP9a with PTX via a succinyl linker. BPP-PTX targets the angiotensin-converting enzyme (ACE) on TNBC cells. ACE was found to be ectopically expressed in two TNBC cell lines but was absent in both the receptor-positive breast cancer cell line and healthy kidney cell line. Overexpression, knockdown, and competitive inhibition experiments demonstrated ACE-mediated cytotoxicity of BPP-PTX. In vivo, ACE-positive tumors were enriched with BPP-PTX, with the PDC being better tolerated than plain PTX. Compared with plain PTX, BPP-PTX exhibited improved tumor-suppressive effects in MDA-MB-468 xenografted female nude mice. Meanwhile, BPP-PTX resulted in less body weight loss and white blood cell reduction toxicity. These results collectively imply the novelty, efficacy, and low-toxicity profile of BPP-PTX as a potential therapeutic for ACE-positive TNBC.

The Vobarno study

INTRODUCTION

The Vobarno study represents the first observational study aimed to assess in a general population sample the relationship between parameters of cardiac and vascular structure (and function) and blood pressure values, measured in the clinic and during the 24 hours.

EVIDENCE ACQUISITION AND SYNTHESIS

In the frame of the Vobarno study blood samples for hematochemistry and DNA extraction, clinic and 24-hour blood pressure measurements, cardiac and carotid ultrasound, and aortic stiffness were measured in all subjects, living in a small town (Vobarno) between Brescia and the Garda lake, and randomly selected from electoral roles. In this sample of a general population an extensive evaluation of organ damage, including left ventricular (LV) mass and hypertrophy, LV systolic function, left atrial dimensions and aortic root diameters, carotid intima media thickness (IMT) and carotid plaques, carotid and aortic stiffness were performed. In this study subjects were included in a long follow-up, lasting 25 years, and cardiovascular morbility and mortality were assessed up to 2019. This will allow to update the information related to cardiovascular morbidity and mortality in the study cohort.

CONCLUSIONS

The present paper will report the results of some analyses performed, exploring epidemiological and clinical aspects of target organ damage.

Association among ACE, ESR1 polymorphisms and preeclampsia in Brazilian pregnant women

BACKGROUND

Genetic, immune and environmental factors are involved in preeclampsia (PE) etiopathogenesis. Considering that hypertension and poor placental perfusion are important features in PE, polymorphisms in the angiotensin-converting enzyme (ACE) and estrogen nuclear receptor 1 (ESR1) genes could be involved in the predisposition and/or development of the disease. The aim of this study was to evaluate if polymorphisms in ACE and ESR1 genes were associated with PE occurrence.

MATERIAL AND METHODS

This case-control study included 209 Brazilian pregnant women (107 with severe PE and 102 normotensive controls). The polymorphisms were investigated by polymerase chain reaction (PCR) followed by polyacrylamide gel electrophoresis.

RESULTS

No significant difference between PE versus normotensive pregnant women, as well as early versus late PE, was observed when compared the allelic and genotypic frequencies of insertion/deletion polymorphism in intron 16 of the ACE gene and the single nucleotide polymorphisms (SNPs - rs2234693 and rs9340799) of the ESR1 gene.

CONCLUSION

This pioneer study involving Brazilian women showed no association among the studied polymorphisms and PE, which suggests that ins/del ACE and SNPs ESR1 do not contribute to this disease occurrence in Brazil.

Comparison of very-high-frequency ultrasound assessment of radial arterial wall layers after first and repeated transradial coronary procedures

BACKGROUND

Transradial coronary procedure (TRP) traumatizes the radial artery (RA), especially resulting in changes to arterial wall morphology. This study explored the significance of the early onset of traumatic effects to wall layers of the RA following the first TRP (FTRP) and repeat TRP (RTRP) using very-high-frequency ultrabiomicroscopy (VHFUBM).

METHODS

A total of 1431 patients that received TRP were divided into the FTRP group that comprised 781 patients and the RTRP group that comprised 650 patients depending on the number of procedures. Two-dimensional RA images were acquired by 30-55 MHz ultrasound one day before and one day after the procedure.

RESULTS

After TRP, the incidence of intimal tears, medial dissections and external elastic lamina fracture were greater in the RTRP (P < 0.001). The RTRP group showed significantly thicker intimal thickness (IT), media thickness (MT), adventitia thickness and all complex layer thicknesses as compared with the FTRP group (P < 0.001).

CONCLUSIONS

Multivariate linear regression analysis discovered that repeated TRP and other observations were independent predictors of increased IT in post-operative RA. VHFUBM provides an approach to study structural and histopathological injury in the wall layers of RA which showed increased trauma to the RA following RTRP.

Association of the KLK1 rs5516 G allele and the ACE D allele with aortic aneurysm and atherosclerotic stenosis

OBJECTIVE

Atherosclerosis underlies aortic aneurysm (AA) and atherosclerotic stenosis (AS). Kallikrein-1 (KLK1) and angiotensin-converting enzyme (ACE) are 2 key molecules in kallikrein-kinin systems and renin-angiotensin systems, respectively, which are responsible for maintaining vascular balance and stability, playing important roles in atherosclerosis. We aimed to assess the involvement of single nucleotide polymorphism rs5516 in KLK1 as well as the insertion/deletion rs4646994 polymorphism in ACE in the development of AA and AS.

METHODS

We enrolled Chinese Han patients with AA (N = 408) and AS (N = 432), as well as healthy controls (N = 408). Clinical and demographic characteristics were assessed. Genotypes were analyzed with recessive and dominant models.

RESULTS

The rs5516 G allele of KLK1 was significantly associated with AA (P < 0.001), and the D allele of ACE was significantly associated with both AA (P < 0.001) and AS (P < 0.001). The GG and DD genotypes were significantly associated with both AA (P = 0.013) and AS (P < 0.001) in a recessive model, and were synergistic with hypertension in AA patients, but not in AS. Patients with CC/DD, CG/ID, or GG/II genotypes, which were synergistic with hypertension, had a greater risk of developing AA, while CC/DD, CG/DD, GG/ID, or GG/DD genotypes, which were not synergistic with hypertension, contributed to the development of AS.

CONCLUSION

The KLK1 rs5516 G allele is closely associated with AA, and the ACE D allele is closely related to AA and AS.

The Effect of ACE Gene Polymorphisms on Doppler Blood Flow Parameters of Carotid and Brachial Arteries in Patients With Myocardial Infarction

The authors investigated the relationship between the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and the blood flow characteristics of common carotid (CCA) and brachial arteries (BA) by color Doppler ultrasound (CDUS) in patients with acute anterior myocardial infarction (AAMI). Sixty four patients (11 women and 53 men), aged 25 to 77 years, with AAMI were studied. The ACE genotypes were established. Peak-systolic (PSV) and end-diastolic velocity (EDV) of right and left CCA, PSV of right BA, and intimal-medial thickness (IMT) of both CCAs were measured by CDUS. All results were evaluated statistically. The ACE genotypes were distributed as follows: 43.8% DD, 43.8% ID, and 12.5% II. PSVs of BA and both CCAs were lower in patients with DD and ID than with II (p<0.05). EDVs of both CCAs were also lower in the same groups, but statistically not significant (p>0.05). IMTs of both CCAs did not differ among patients with various ACE genotypes (p>0.05). These results suggest that ACE I/D polymorphism influences Doppler blood flow parameters of both BA and CCA, but does not affect IMT of CCA.

Graphical chain models for the analysis of complex genetic diseases: an application to hypertension

A crucial task in modern genetic medicine is the understanding of complex genetic diseases. The main complicating features are that a combination of genetic and environmental risk factors is involved, and the phenotype of interest may be complex. Traditional statistical techniques based on lod-scores fail when the disease is no longer monogenic and the underlying disease transmission model is not defined. Different kinds of association tests have been proved to be an appropriate and powerful statistical tool to detect a ‘candidate gene’ for a complex disorder. However, statistical techniques able to investigate direct and indirect influences among phenotypes, genotypes and environmental risk factors, are required to analyse the association structure of complex diseases. In this paper, we propose graphical models as a natural tool to analyse the multifactorial structure of complex genetic diseases. An application of this model to primary hypertension data set is illustrated.

Impact of renin-angiotensin-aldosterone system genes on the treatment response of patients with hypertension and metabolic syndrome

Objective. To evaluate the influence of clinical, biochemical and genetic markers on the response to antihypertensive treatment in patients with essential hypertension and the metabolic syndrome (MetS).

Methods. Measurements of anthropometric indices, blood pressure (BP), and metabolic parameters were obtained from the medical records of 132 (77 women) newly diagnosed, untreated hypertensive patients. Renin-angiotensin-aldosterone system (RAAS) genes polymorphisms (including ACE I/D, angiotensinogen M235T, angiotensin II type 1 receptor [AT1-receptor] A1166C) were determined. Response to treatment was defined as BP less than 140/90 mmHg.

Results. Patients with MetS (n=60) had higher systolic BP and pulse pressure and a more atherogenic lipid profile than patients without MetS.The frequencies of the ACE and the AT1-receptor gene polymorphisms were similar between patients with and without MetS. Response to treatment was positively associated with pulse pressure, and the presence of the C allele as well as the AC genotype of the AT1-receptor gene and inversely with age after adjustment for confounding factors.

Conclusions. RAAS genes distribution does not differ between hypertensive patients with and without the MetS. Higher baseline pulse pressure levels, the presence of the C allele and/or the AC genotype may be in favour of a better response to structured antihypertensive treatment in patients with MetS. However, these findings need to be evaluated in future studies.

Fast high-throughput screening of angiotensin-converting enzyme insertion/deletion polymorphism by variable programmed electric field strength-based microchip electrophoresis

An insertion (I)/deletion (D) polymorphism in angiotensin-converting enzyme (ACE) has been associated with susceptibility to various diseases in numerous studies. Traditionally, slab gel electrophoresis (SGE) after polymerase chain reaction (PCR) has been used to genotype this ACE I/D polymorphism. In this study, single- and multi-channel microchip electrophoresis (ME) methods based on variable programmed electric field strength (PEFS) (i.e., low constant, high constant, (+)/(-) staircase, and random electric field strengths) were developed for fast high-throughput screening of this specific polymorphism. The optimum PEFS conditions were set as 470V/cm for 0-9s, 129V/cm for 9-13s, 470V/cm for 13-13.9s, 294V/cm for 13.9-16s, and 470V/cm for 16-20s for single-channel ME, and 615V/cm for 0-22.5s, 231V/cm for 22.5-28.5s, and 615V/cm for 28.5-40s for multi-channel ME, respectively. In the multi-channel PEFS-ME, target ACE I/D polymorphism DNA fragments (D=190bp and I=490bp) were identified within 25s without loss of resolving power, which was ∼300 times faster than conventional SGE. In addition, PCR products of the ACE gene from human blood samples were detected after only 10 cycles by multi-channel PEFS-ME, but not by SGE. This parallel detection multichannel-based PEFS-ME method offers a powerful tool for fast high-throughput ACE I/D polymorphism screening with high sensitivity.

Association of the ACE rs4646994 and rs4341 polymorphisms with the progression of carotid atherosclerosis in slovenian patients with type 2 diabetes mellitus

The current study was designed to reveal possible associations between the angiotensin-converting-enzyme (ACE) gene polymorphisms (rs4646994 and rs4341) with markers of carotid atherosclerosis in patients with type 2 diabetes mellitus (T2DM) in a 4-year-long follow-up study. Five hundred and ninety-five T2DM subjects and 200 control subjects were enrolled. Genotyping of ACE polymorphisms was performed using KASPar assays, and ultrasound examinations were performed twice (at the enrollment and at follow-up). With regard to the progression of atherosclerosis in subjects with T2DM, statistically significant differences were demonstrated in the change of the sum of carotid plaques thickness for the rs4646994 polymorphism. We did not demonstrate an association between the tested polymorphisms (rs4646994 and rs4341) and either carotid intima media thickness (CIMT) or CIMT progression in a 3.8-year period. In our study, we demonstrated that subjects with T2DM with the DD genotype of the rs4646994 [ACE insertion/deletion (I/D)] polymorphism had faster progression of atherosclerosis in comparison to subjects with other genotypes.

Endothelial function and germ-line ACE I/D, eNOS and PAI-1 gene profiles in patients with coronary slow flow in the Canakkale population: multiple thrombophilic gene profiles in coronary slow flow

Background

We examined the effects of ACE, PAI-1 and eNOS gene polymorphisms on endothelial function. The genes are related to atherosclerosis and endothelial dysfunction in coronary slow flow (CSF).

Methods

Thirty-three patients with angiographically proven CSF and 48 subjects with normal coronary flow were enrolled in this study. Coronary flow patterns were determined by the thrombolysis in myocardial infarction (TIMI) frame count method. Endothelial function was assessed in the brachial artery by endothelium-dependent flow-mediated dilatation (FMD). PAI-1 4G/5G, eNOS T-786C and ACE I/D polymorphisms were determined by polymerase chain reaction (PCR) amplification.

Results

No difference was found between the groups regarding age, heart rate and blood pressure. Males were more prevalent among patients with CSF than control subjects (58.8 vs 29.8%, p = 0.009). Mean TIMI frame counts were significantly higher in CSF patients (24.2 ± 4.0 vs 13.1 ± 2.5 fpm, p = 0.001). FMD was significantly lower in CSF patients than in the controls (4.9 ± 6.6 vs 7.9 ± 5.6%, p = 0.029). TIMI frame count and FMD were found to be negatively correlated in a correlation analysis (r = –0.269, p = 0.015). PAI-1 4G/5G, eNOS T-786C and ACE I/D polymorphisms were similar in the two groups.

Conclusions

This study showed that endothelial function was impaired in patients with CSF. PAI-1, ACE and eNOS polymorphisms were not related to CSF in our study population.

Influence of the angiotensin converting enzyme insertion or deletion genetic variant and coronary restenosis risk: evidence based on 11,193 subjects

The insertion/deletion (I/D) polymorphism of the gene encoding angiotensin converting enzyme is a controversial risk factor for restenosis after percutaneous transluminal coronary angioplasties (PTCA) in patients. Genetic association studies can be problematic to reproduce due to insufficient power, phenotypic heterogeneity, population stratification, small effect of the variant and even publication biases. To derive a more precise estimation of the relationship as well as to quantify the between-study heterogeneity and potential bias, a meta-analysis including 11,193 patients from 33 published cohort studies was performed. In a combined analysis, the summary per-allele odds ratio for restenosis was 1.31 (95% CI: 1.08-1.58, P = 0.006), and 1.22 (95% CI: 0.95-1.56, P = 0.12), for PTCA-stent and PTCA-balloon, respectively. In the subgroup analysis by ethnicity, significantly increased restenosis risks after PTCA-stent were found in Asians for the polymorphism; whereas no significant associations were found among Caucasians. As for restenosis risks after PTCA-balloon, no evidence of any gene-disease association was obtained in the stratified analyses according to ethnicity and study size. In conclusion, this meta-analysis demonstrated that the DD homozygous of ACE I/D polymorphism was significantly associated with elevated restenosis susceptibility after PTCA-stent among Asian populations.

Genetic polymorphism of angiotensin converting enzyme and risk of coronary restenosis after percutaneous transluminal coronary angioplasties: evidence from 33 cohort studies

Background

In the past decade, a number of cohort studies studies have been carried out to investigate the relationship between the insertion/deletion polymorphism of the gene encoding angiotensin-converting enzyme and risk of restenosis after percutaneous transluminal coronary angioplasties in patients. However, these studies have yielded contradictory results. Genetic association studies addressing this issue are frequently hampered by insufficient power. We therefore performed a meta-analysis of the published studies to clarify this inconsistency and to establish a comprehensive picture of the relationship between ACE I/D polymorphism and post-PTCA restenosis risk.

Methods

Databases including Pubmed, EMBASE, ISI Web of Science, EBSCO, Cochrane Library databases and CNKI were searched to find relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association. The random-effects model was applied, addressing heterogeneity and publication bias.

Results

A total of 33 cohort studies involving 11,099 subjects were included. In a combined analysis, the OR for post-PTCA restenosis of the ACE DD genotype was 1.61 (95% CI: 1.27–2.04; P<10⁻⁵). In the subgroup analysis by intervention, significantly increased risks were also found in PTCA-stent and PTCA-balloon for the DD genotype of the polymorphism.

Conclusions

Our meta-analysis showed that the DD genotype of ACE I/D polymorphism was significantly associated with increased risk of restenosis, particularly for PTCA-stent.

A study of ACE and ADD1 polymorphism in ischemic and hemorrhagic stroke

BACKGROUND

Stroke is a common cerebrovascular accident. ACE and ADD1 gene are known to be associated with vascular complications leading to stroke susceptibility. The present study was carried out to evaluate the relative frequency of ACE and ADD1 common polymorphisms in ischemic stroke and intracerebral hemorrhage (ICH).

METHODS

A total of 386 CT or MRI proven stroke patients were included; 193 each had ischemic stroke and ICH. The locations and type of stroke were noted. ACE- I/D (rs4646994) and ADD1 (rs4961) gene polymorphisms were analyzed by polymerase chain reaction (PCR). The genotype and allele frequencies of ACE and ADD1 polymorphisms were compared between patients and controls as well as between ischemic stroke and ICH.

RESULTS

ACE (DD) genotype was significantly higher in ischemic stroke (37.8%) and ICH (33.7%) compared to controls (11.7%). D allele was also more frequent in ischemic stroke (57.3%) and ICH (56.7%) compared to controls (38.3%). ADD1 (WW) genotype and W allele frequencies were not significantly different in ischemic stroke, ICH and controls. In contrast, we found a synergistic role of ACE (DD)*ADD1(GW) interaction showing a positive association in both ischemic and hemorrhagic strokes.

CONCLUSION

Our study suggests that ACE (DD) genotype and D allele significantly increase the susceptibility to ischemic and hemorrhagic strokes.

Increased intima thickness of the radial artery in patients with coronary heart disease

Ultrabiomicroscopy is a novel high-frequency (55 MHz) ultrasound technique that could be used to non-invasively measure the vessel wall and separate the intima—media complex into measurements of intima and media thickness. Since no previous study has measured intima and media thickness separately in vivo in patients with coronary heart disease (CHD), the aim of the current study was to measure intima and intima—media thickness of the radial and the anterior tibial arteries among patients with CHD and healthy subjects (HS). Thirty-two patients with CHD and 46 HS underwent investigations with ultrabiomicroscopy measurements of the radial and anterior tibial arteries. Patients with CHD showed a 19% increase in intima thickness of the radial artery compared with HS (0.088 ± 0.024 mm versus 0.074 ± 0.015 mm; p < 0.015), whereas no difference was seen in media thickness. There were no differences in intima or media thickness within the anterior tibial arteries. In conclusion, CHD is associated with thickening of the intima of the radial artery whereas media thickness was unchanged compared with HS. Assessment of intima thickness by high-frequency ultrasound may provide a tool for non-invasive early detection of atherosclerosis.

Effects of age, genes, and pulse pressure on executive functions in healthy adults

Executive functions (EF) evidence significant age-related declines, but the mechanisms underpinning those changes are unclear. In this study, we focus on two potential sources of variation: a physiological indicator of vascular health, and genetic variants related to vascular functions. In a sample of healthy adults (n=158, ages 18-81), we examine the effects of age, pulse pressure, and two polymorphisms (comt val158met and ace insertion/deletion) on working memory and cognitive flexibility. Results indicate that in addition to often-replicated age differences, the alleles of two polymorphisms that promote vasoconstriction (comt val and ace D) and reduced availability of dopamine in neocortical synapses (comt val), negatively impact virtually all aspects of EF tasks that involve working memory. In some cases, suppression of cognitive performance is limited to men or necessitates a combination of both risk-associated alleles. After accounting for genetic and age-related variation, pulse pressure had no additional effect on EF. These findings suggest that in healthy adults, the effects of genetic risk factors significantly modulate the course of cognitive aging.

Angiotensin-converting enzyme gene and retinal arteriolar narrowing: the Funagata Study

The purpose of this study is to determine whether the angiotensin-converting enzyme (ACE) gene polymorphism is associated with retinal arteriolar narrowing, a subclinical marker of chronic hypertension. The Funagata Study examined a population-based sample of Japanese aged 35+ years; 368 participants had both retinal vessel diameter measurements and ACE insertion/deletion (ACE I/D) polymorphism analyses performed. Assessment of retinal vessel diameter and retinal vessel wall signs followed the protocols used in the Blue Mountains Eye Study. ACE gene polymorphisms D/D, I/D and I/I were present in 34 (9.2%), 170 (46.2%) and 164 (44.5%) participants, respectively, distributed in Hardy-Weinberg equilibrium. After multivariable adjustment, retinal arteriolar diameter was significantly narrower in subjects with the D/D genotype compared to subjects with I/D and I/I genotypes (mean difference -6.49 microm, 95% confidence interval (CI): -12.86 microm, -0.11 microm). Our study suggests that the ACE I/D polymorphism may be associated with subclinical structural arteriolar changes related to chronic hypertension.

Lack of association between the insertion/deletion polymorphism of the angiotensin-converting enzyme gene and vasospastic angina

BACKGROUND AND HYPOTHESIS

It has been suggested that the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene is an independent risk factor for coronary atherosclerosis and myocardial infarction, but its relation to vasospastic angina has not been fully proven. In the present study, we investigated the possible relationship between the ACE I/D genotype and vasospastic angina.

METHODS

We explored the distribution of the ACE genotype in 20 patients with vasospastic angina without fixed coronary artery stenosis, 55 angina patients with fixed coronary artery stenosis, and 30 control subjects without coronary artery disease.

RESULTS

The frequency of the DD genotype in patients with vasospastic angina (DD: 30.0%, ID: 20.0%, II: 50.0%) did not differ from that in the control subjects (DD: 23.3%, ID: 26.7%, II: 50.0%), while the frequency in patients with coronary artery stenosis (DD: 43.7%, ID: 21.8%, II: 34.5%) was significantly higher than that in the control subjects. The frequency of the D allele also did not differ between patients with vasospastic angina (0.40) and control subjects (0.37), while the frequency was significantly higher in patients with coronary artery stenosis (0.55).

CONCLUSIONS

These findings suggest that the ACE DD genotype is a potent genetic risk factor for organic coronary artery disease, while it confers no appreciable increase in risk of vasospastic angina. These results also suggest the diversity of the pathogenesis of vascular lesions in these two types of coronary artery disease.

Genetic influences on 24 h blood pressure profiles in a hypertensive population: role of the angiotensin-converting enzyme insertion/deletion and angiotensin II type 1 receptor A1166C gene polymorphisms

OBJECTIVE

Data on the association of the ACE I/D and AT1R A1166C polymorphisms with hypertension are conflicting. Most studies, however, have focused on office blood pressure (BP) only. The objective of the present study was to investigate the association of BP with the angiotensin-converting enzyme insertion/deletion (ACE I/D) and angiotensin II type 1 receptor A1166C (AT1R A1166C) polymorphisms by means of both office and ambulatory blood pressure monitoring (ABPM).

METHODS AND RESULTS

A total of 348 hypertensive patients participated in this study. Office BP did not differ between the various ACE or AT1R genotype groups. However, ambulatory BP and BP load were positively associated with the ACE I/D polymorphism. This was more apparent in men than in women. There were no differences in heart rate, BP variability, and amount of dipping. The AT1R A1166C polymorphism showed no consistent association with blood pressure (load).

CONCLUSION

From these data we conclude that frequent measuring of blood pressure by ABPM is crucial to find an association of the ACE D allele with various aspects of blood pressure.

The geographic distribution of the ACE II genotype: a novel finding

Angiotensin converting enzyme (ACE) gene polymorphism insertion (I) or deletion (D) has been widely studied in different populations, and linked to various functional effects and associated with common diseases. The purpose of the present study was to investigate the relationship between the ACE I/D frequency in different populations and geographic location; ACE I/D allele frequency in the Lebanese population and ACE II genotype contribution to the geographic trend were also identified. Five hundred and seventy healthy volunteers were recruited from the Lebanese population. Genomic DNA was extracted from buccal cells, and amplified by polymerase chain reaction; products were then identified by gel electrophoresis. The frequencies of the different ACE I/D genotypes were determined and tested for Hardy-Weinberg equilibrium (HWE). To assess the relationship between ACE I/D frequency and geographic location, and to identify how the Lebanese population contributes to the geographic trend in ACE I/D frequencies, Eurasian population samples and Asians were incorporated in the analyses from the literature. The frequency of the I allele in the Lebanese population was 27% and the corresponding II genotype was at a frequency of 7.37% (in HWE; P=0.979). The ACE I allele and genotype frequencies show an association with longitude, with frequencies increasing eastwards and westwards from the Middle East.

Prevalence of Thrombophilic Mutations and ACE I/D Polymorphism in Turkish Ischemic Stroke Patients

The aim of this study was to evaluate the prevalence of factor V Leiden (FVL), prothrombin G20210A, methylenetetrahydrofolate reductase ( MTHFR) C677T gene mutations, and angiotensin-converting enzyme (ACE) I/D polymorphism in ischemic stroke (IS) patients. A total of 162 Turkish IS patients were included and analyzed according to stroke subtype by the TOAST classification. Their genotype data were compared with those of the control group, representing the healthy population, using the χ2 test. The frequency of FVL heterozygocity was 12.3% in this series—higher than that in the normal population (9.8%; statistically insignificant, P = .478). The frequency of the ACE D/D genotype in all stroke patients and those with stroke of undetermined etiology was higher than that in our population (52.5% and 59.2%, respectively, vs 39.3%; statistically significant, P = .034, P = .020). Our results may suggest that ACE D/D genotype is a risk factor for IS, particularly in those with stroke of undetermined etiology in the Turkish population.

Early sign of atherosclerosis in slow coronary flow and relationship with angiotensin-converting enzyme I/D polymorphism

Increase in carotid artery intima-media thickness (IMT) is an early sign of atherosclerosis. Slow coronary flow (SCF) is characterized by delay of opacification of coronary arteries in coronary angiography in the absence of any evident obstructive lesion, but its etiopathogenesis remains unclear. Genes that regulate the renin angiotensin system also play a role in developing cardiovascular system disorders. The presence of deletion (D) allele in angiotensin converting enzyme (ACE) gene polymorphism is associated with coronary artery disease. The aim of this study was to investigate the carotid artery IMT measurement, as an early sign of atherosclerosis, in patients with SCF and without SCF and also to assess the effect of the renin-angiotensin gene system on carotid IMT. Forty-four patients with angiographically proven SCF and 44 cases with normal coronary flow (NCF) pattern with similar risk profile were enrolled in the study. Coronary flow patterns of the cases were determined by thrombolysis in myocardial infarction (TIMI) frame count method. Intima-media thickness was measured by recording ultrasonographic images of both the left and right common carotid artery with a 12-MHz linear array transducer. ACE I/D polymorphism and Angiotensin II tip 1 receptor (AT1R) A/C gene polymorphism were determined by polymerase chain reaction (PCR) amplification. Demographic characteristics and coronary artery disease risk factors of SCF and NCF groups were similar. Mean TIMI frame count and carotid IMT (mm) were significantly higher in the SCF group than controls (45.9 +/- 12 vs 23.3 +/- 3.7, P = 0.0001; 0.75 +/- 0.08 vs 0.69 +/- 0.06, P = 0.0001, respectively). Mean TIMI frame count was positively correlated with IMT of carotid artery in correlation analysis (r = 0.45, P = 0.0001). When analyzed in regard to ACE genotype in all subjects, IMT values were statistically different (0.78 +/- 0.06 for DD genotype, 0.72 +/- 0.05 for ID genotype, and 0.64 +/- 0.06 for II genotype, P = 0.0001). This difference remained significant in subgroup analyses for each genotype. No association could be observed between the AT1R A/C(1166) polymorphism and IMT of carotid artery measurement (P > 0.05). Lack of association was still observed with analysis carried out when genotype effect was assumed to be inherited as additive (CC versus AA versus AC) or dominant (AA versus AC+CC). Increased IMT in patients with SCF shows that subclinical atherosclerosis may play role in this phenomenon. This increase was most marked in the presence of D allele of ACE genotype, which is associated with vascular hypertrophy.

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.

Polymorphism of the angiotensin-converting enzyme (ACE) and angiotesinogen (AGT) genes and their associations with blood pressure and carotid artery intima media thickness among healthy Finnish young adults--the Cardiovascular Risk in Young Finns Study

The roles of angiotensin converting enzyme (ACE) insertion-deletion (I/D) and angiotensinogen (AGT) m235t polymorphisms in cardiovascular diseases have been investigated extensively during the past decade but results have been inconsistent. A sex-specific association between the ACE I/D polymorphism and systolic blood pressure (BP) was seen among Finnish children and adolescents previously. We investigated if these polymorphisms associate with the BP and carotid artery intima media thickness (IMT) in the same cohort during their adulthood. IMT data were available for 224 ACE I/D genotyped individuals and 202 AGT m235t genotyped individuals. Systolic and diastolic blood pressure values did not differ between ACE and AGT genotypes. Age and BMI adjusted mean IMT was 0.02 (95% CI: -0.05 to 0.02, p=0.33) and 0.03 mm (95% CI: -0.07 to 0.001, p=0.06) lower among the ID and DD genotype groups, respectively, compared to the II genotype group. MT and TT genotype groups had 0.02 mm (95% CI: -0.01 to 0.05, p=0.17) higher and 0.01 mm (95% CI: -0.04 to 0.02, p=0.59) lower mean IMT, respectively, compared to the MM genotype group. We conclude that ACE I/D and AGT m235t polymorphisms are not associated with carotid IMT in healthy young Finnish adults.

Effects of angiotensin-converting enzyme polymorphism on aortic elastic parameters in athletes

BACKGROUND

Physiologic adaptations in an athlete's heart include increased left and right ventricular chamber size, left ventricular wall thickness and mass. Angiotensin-converting enzyme (ACE) is a key enzyme in angiotensin II production causing cardiac hypertrophy. The cloning of the ACE gene has made it possible to identify a deletion (D)-insertion (I) polymorphism that appears to affect the level of serum ACE activity. Therefore, the ACE genes, which have been shown to be polymorphic, could be candidate genes for large-artery stiffness.

METHODS

56 endurance athletes and 46 sedentary subjects were included in this study, and they underwent both complete echocardiographic examination, and analysis of ACE insertion (I) and deletion (D) allele frequencies in peripheral blood. The aortic diameter was recorded by M-mode echocardiography at a level 3 cm above the aortic valve. Aortic systolic diameter was measured at the time of full opening of the aortic valve, and diastolic diameter was measured at the peak of QRS. Aortic strain, stiffness index and distensibility were calculated.

RESULTS

Left ventricular mass index and left ventricular ejection fraction were significantly higher in athletes than controls (p < 0.001). The aortic distensibility index and strain were significantly greater in athletes compared with controls (respectively: 5.8 +/- 2.7 vs. 4.7 +/- 1.8 cm(-2) dyn(-1) 10(-6), p = 0.017; 12.3 +/- 2.4 vs. 9.3 +/- 3.1, p < 0.001). The aortic stiffness index was significantly lower in athletes than in controls (4.8 +/- 1.9 vs. 6.1 +/- 2.1, p < 0.001). The aortic distensibility index and strain were statistically different in ACE DD vs. DI groups and DD vs. II groups of athletes. The aortic stiffness index was statistically different in ACE DD vs. II groups of athletes. Aortic parameters were similar according to ACE genotypes in controls.

CONCLUSION

The results of this study indicate that aortic distensibility was increased by prolonged training in endurance athletes, particularly in those with the ACE II genotype. This effect represents an extracardiac adaptation to chronic prolonged training in athletes.

POLYMORPHISMS OF APOLIPOPROTEIN E AND ANGIOTENSIN-CONVERTING ENZYME GENES AND CAROTID ATHEROSCLEROSIS IN HEAVY DRINKERS

AIMS

To investigate the influence of apolipoprotein E (APOE) and angiotensin-converting enzyme (ACE) gene polymorphisms on carotid artery atherosclerosis in alcoholism.

METHODS

Polymorphism of both genes was identified by DNA analysis in 130 male alcohol-dependent patients. Intima-media thickness (IMT) was measured ultrasonographically.

RESULTS

Multivariate regression analysis showed that of all the known risk factors the greatest impact on carotid atherosclerosis in alcoholics was exerted by age, hypertension, LDL cholesterol and fasting plasma glucose levels. Subjects carrying the APO E epsilon4 allele were more liable to develop atherosclerotic changes in carotid arteries compared with subjects with the epsilon3/3 genotype, which showed statistical significance in patients under 50 years of age. No association was shown between ACE I/D polymorphism and carotid atherosclerosis.

CONCLUSIONS

APO E polymorphism can increase the risk of carotid atherosclerosis development in an alcoholic subject. The association of the APO E epsilon4 allele with carotid atherosclerosis was significant in younger patients. Since the elevated carotid IMT is considered to be a good marker of increased risk of generalized atherosclerosis the consequences could involve both cardiac and cerebrovascular events.

Intima???media complex of both the brachial artery and the common carotid artery are associated with left ventricular hypertrophy in patients with previous myocardial infarction

OBJECTIVES

Prospective trials have established intima-media thickness (IMT) of the carotid artery, flow-mediated dilation (FMD) of the brachial artery and cardiac left ventricular hypertrophy (LVH) as predictors of cardiovascular events. The aim of this study was to examine the relationship between intima-media complex of the brachial artery to FMD, intima-media complex of the common carotid artery and cardiac hypertrophy in patients with coronary heart disease.

METHODS AND PROCEDURES

Cross-sectional design. Procedures were undertaken within the Huddinge University Hospital, Karolinska Institute, Stockholm, Sweden. A total of 123 patients with a previous acute myocardial infarction (MI) were investigated. Calculated intima-media area (cIMa) of the brachial and common carotid arteries and FMD of the brachial artery and left ventricular dimensions were examined.

RESULTS

The brachial cIMa was significantly associated with age, p-triglycerides, common carotid cIMa, ejection fraction, septum thickness, posterior wall thickness and left ventricular mass index (P < 0.05). Brachial cIMa also tended to be associated with systolic blood pressure (P = 0.056). Common carotid cIMa was significantly associated with age, systolic blood pressure, brachial cIMa, FMD and septum thickness (P < 0.05). FMD was significantly associated with age and carotid cIMa (P < 0.05).

CONCLUSION

Both cIMa of the common carotid artery and the cIMa of the brachial artery were independently and significantly associated with ventricular septum thickness of the heart in patients with previous myocardial infarction.

Vascular injury in systemic sclerosis: Angiotensin-converting enzyme insertion/deletion polymorphism

The microvascular involvement in systemic sclerosis (SSc) is characterized by endothelial damage and smooth muscle cell migration in the intima. The vascular pathologic modifications in SSc are strikingly similar to those of atherosclerosis. SSc also is characterized by an accelerated macrovascular disease. The gene encoding for angiotensin-converting enzyme (ACE) is a 21-kb, 26-exon gene, localized on chromosome 17 (17q23). Polymorphic sites are an insertion/deletion (I/D) that consists of three genotypes: DD and II homozygotes, and ID heterozygote. ACE gene polymorphisms have been linked to vascular disorders (coronary artery disease, hypertension, cerebrovascular disease, hypertrophic cardiomyopathy, and diabetic or nondiabetic nephropathy). In particular, the possession of ACE D allele was associated with an increased risk of developing malignant vascular injury. ACE D allele frequency of the I/D polymorphism was associated with an increased risk of SSc, suggesting a genetic contribution to the disease. The discrepancy between the high prevalence of D allele and reduced ACE plasma levels in SSc demonstrate the lack of knowledge on the regulation and function of renin-angiotensin system in SSc.

A study of gene--environment interaction on the gene for angiotensin converting enzyme: a combined functional and population based approach

INTRODUCTION

Studies on the role of the insertion/deletion (I/D) polymorphism of the gene coding for angiotensin converting enzyme (ACE) in atherosclerosis have been inconsistent. In a meta-analysis, we recently showed that this relationship is stronger in high risk populations. In this paper, we used a combined functional and population based approach to investigate the gene-environment interaction of the ACE I/D polymorphism in relation to carotid artery wall thickness.

METHODS

The study was part of the Rotterdam Study, a prospective population based cohort study. In 5321 subjects, IMT was measured in the carotid arteries by ultrasonography and ACE genotype was determined by size analysis of polymerase chain reaction products.

RESULTS

In multiple regression analysis, I/D polymorphism and smoking were the main determinants for plasma ACE activity (r(2) = 0.28). There was a positive association between the D allele of the I/D polymorphism and carotid artery thickness among current smokers (p = 0.03). Subjects carrying only one of the risk factors (smoking or the D allele) did not show significant differences in IMT compared with the non-/former smokers group carrying two II alleles, while carriers of both risk factors had significant higher IMT. The association was not present in non-/former smokers.

DISCUSSION

The results provide further evidence that genetic and environmental factors interact in the formation of the arterial lesions. This study shows that large population based studies can be extremely helpful in unravelling the genetic origin of complex diseases such as atherosclerosis.

Genetics of intima-media thickness

PURPOSE OF REVIEW

Increased carotid artery intima-media thickness is associated with an increased risk of coronary heart disease or cerebrovascular disease and is a powerful predictor of cardiovascular and cerebrovascular outcomes. Consequently, the measurement is now used in a number of case control, cohort and familial and linkage studies as an intermediate phenotype for the investigation of the genetic and environmental determinants of atherosclerosis. The aim of this paper is to review the most recent available data on the genetic determinants of carotid intima-media thickness.

RECENT FINDINGS

Genes could account for a significant amount of variation in carotid intima-media thickness: up to 30-66%. Carotid intima-media thickness progressed more rapidly with age in familial hypercholesterolemia patients than in patients without his condition. Familial hypercholesterolemia patients with a null LDL receptor allele tended to have higher carotid intima-media thickness than patients carrying the LDL receptor defective allele. Small association studies showing positive or negative results with the angiotensinogen gene variants as well as with the angiotensin converting enzyme I/D polymorphism add to the confusion in this largely controversial area. Differing results may depend on the vascular territory and genetic background. New associations have been described in small studies.

SUMMARY

Studies on the association of polymorphisms and intima-media thickness are frequently disappointing and lead occasionally to conflicting results. Among study limitations is the fact that mostly single gene effects are considered; longitudinal cohort studies may be more appropriate than case control studies. Ongoing large prospective population studies and clinical trials have integrated the measurements of intima-media thickness and genotype determination with a genomic approach. As a result, in the near future we may see more important and robust results with significant consequences on our understanding of genetic determinants of atherosclerotic cardiovascular disease.

HLA phenotypes as promoters of cardiovascular remodelling in subjects with arterial hypertension

The objective of this study was to investigate the association between human leukocyte antigens (HLA) phenotypes and cardiovascular remodelling, as expressed by left ventricular mass (LVM) and carotid intima-media thickness (IMT), in hypertensives. We examined 153 subjects with arterial hypertension and 61 normotensive controls living in the greater Athens area. The population was classified into three groups and specifically group I (normotensives), group II with Grade 1 hypertension and group III with Grade 2 or 3 hypertension. HLA class I and class II antigens were studied by microlymphocytotoxic technique. Carotid IMT and LVM were determined by ultrasonography. The prevalence of HLA DQ7 in the hypertensive cohort was 27.4% that was significantly smaller than the 52.5% among the controls (P = 0.002). The HLA DR11 was found in 24.0% of the hypertensives and in 52.5% of the controls (P < 0.001). Group III hypertensives with HLA DR11 exhibited significantly higher LVM/h in comparison to the hypertensives without this HLA (199.0 +/- 28.8 vs 171.2+44.1g/m, P = 0.009). This association was not present in groups I and II. Similarly, group III hypertensives with HLA DQ7 were characterized by higher IMT in comparison to those without this HLA (0.94 +/- 0.19 vs 0.83 +/- 0.23 mm, P = 0.048). HLA DR17 was associated with higher IMT in both groups II and III (1.00 +/- 0.19 vs 0.82 +/- 0.19 mm, P = 0.046 and 1.01 +/- 0.23 vs 0.84 +/- 0.22 mm, P = 0.049, respectively) but not in group I. In conclusion, certain HLA phenotypes may be related to the levels of arterial blood pressure. Moreover, it seems that these HLA phenotypes may identify subjects with arterial hypertension that are more prone to develop cardiovascular hypertrophy.

Angiotensin-converting enzyme gene polymorphism may influence blood loss in a geriatric population undergoing total hip arthroplasty

OBJECTIVES

To evaluate how angiotensin-converting enzyme (ACE) gene polymorphism is associated with perioperative blood loss in hip arthroplasty in a geriatric population.

DESIGN

A case-control study of subjects consecutively undergoing total hip arthroplasty.

SETTING

A department of orthopedic surgery in Italy.

PARTICIPANTS

One hundred five patients, mean age +/- standard deviation 68.6 +/- 10.4, undergoing total hip arthroplasty.

MEASUREMENTS

ACE gene polymorphism was analyzed using polymerase chain reaction. Decrement of hemoglobin (Hb) and hematocrit (Ht) was calculated as the difference between the preoperative and the lowest postoperative value, measured 1, 2, and 3 days after surgery. Total blood loss was calculated as the sum of intra- and postoperative blood loss.

RESULTS

Patients carrying the deletion homozygous and insertion/deletion heterozygous genotypes of the ACE gene show a higher decrement of Hb (P <.01) and Ht (P <.01) and higher total blood loss (P <.007) after hip surgery than subjects carrying the insertion (II) homozygous. The role of ACE gene polymorphism seems hypertension independent. Logistic regression analysis showed that II genotype reduces total blood loss.

CONCLUSIONS

This is the largest study evaluating the distribution of ACE gene genotypes in patients undergoing hip arthroplasty and the first investigating the association between bleeding and ACE gene polymorphism. Our data suggest that II genotype is associated with lower total blood loss.

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.

Intima-media thickness of the common carotid arteries is related to coronary atherosclerosis and left ventricular hypertrophy in older adults

Increased intima-media thickness (IMT) of the common carotid arteries is related to generalized atherosclerosis and increased risk of future myocardial infarction and cerebrovascular disease. An association between IMT and the presence of coronary artery disease (CAD) has been documented, but controversial data have been found about the relation between increased IMT and the extent of CAD. An association between carotid atherosclerosis and cardiac remodeling has also been reported. It is still unclear whether increased IMT of the common carotid arteries might be associated with prevalent cardiovascular disease in older adults. This study included 70 patients, 37 with CAD and 33 matched for age and gender without CAD. All patients underwent a baseline clinical examination, B-mode ultrasound of the carotid arteries, and echocardiography. The authors evaluated the possible association between increased IMT with the presence and extent of CAD and the presence of left ventricular hypertrophy (LVH). The patients with CAD had significantly increased IMT compared to patients without CAD. IMT was found to increase with the number of coronary vessels affected, after adjustment for age, gender, hypertension, hypercholesterolemia, diabetes mellitus, and smoking habits. The test for trend was highly significant (p<0.001). Patients with LVH had significantly increased IMT as compared with patients without LVH. IMT of the common carotid arteries was increased in the presence of CAD and increased with the number of coronary vessels diseased. Second, the authors found that IMT of the common carotid arteries was significantly increased in patients with LVH. Increased IMT, as an indicator of subclinical cardiovascular disease, may help to identify patients who would benefit from aggressive therapeutic measures.

Carotid and femoral intima-media thickness in relation to three candidate genes in a Caucasian population

BACKGROUND

In a Caucasian population, the prevalence and incidence of hypertension, renal function and large artery stiffness were significantly correlated with polymorphisms in the genes encoding the angiotensin-converting enzyme (ACE I/D), aldosterone synthase (-C344T) and the cytoskeleton protein alpha-adducin (Gly460Trp).

OBJECTIVE

This study investigated intima-media thickening, a precursor of atherosclerosis, in relation to these genetic polymorphisms.

METHODS

Carotid and femoral intima-media thickness were assessed with a wall-track system in 380 subjects enrolled in a population study. Subjects were genotyped for the presence of the ACE D, aldosterone synthase -344T and alpha-adducin 460Trp alleles. The statistical analysis allowed for confounders, interactions among genes, and the non-independence of the phenotypes within families.

RESULTS

The sample included 188 men (49.5%). Mean age was 39.8 years. Intima-media thickness of the carotid and femoral arteries averaged 575 and 719 microm, respectively. Intima-media thickness of the femoral-but not carotid-artery increased with the number of ACE D alleles. The effect of ACE genotype on femoral intima-media thickness was confined to carriers of the 460Trp allele and the -344T allele. Expressed as a percentage of the population mean, the mean differences between II and DD homozygotes averaged 13.4% (95% CI 5.6-21.2%) in all subjects, 21.2% (8.0-34.5%) in carriers of the 460Trp allele, 15.4% (4.1-26.8%) in carriers of the -344T allele, and 25.2% (10.7-39.7%) if the 460Trp and -344T alleles were both present.

CONCLUSION

This study shows that a relationship exists between the intima-media thickness of the large muscular femoral artery and the ACE gene. This relationship is only apparent in the presence of either the alpha-adducin 460Trp or the aldosterone synthase -344T allele. These findings may have clinical implications for the assessment of genetic cardiovascular risk.

Progression of atherosclerosis in patients with peripheral arterial disease as a function of angiotensin-converting enzyme gene insertion/deletion polymorphism

Angiotensin-converting enzyme insertion/deletion (I/D) gene polymorphism plays a role in determining the inter-individual variability of circulating angiotensin-converting enzyme activity and intracellular angiotensin-converting enzyme levels. Angiotensin-converting enzyme, as a key enzyme in the renin-angiotensin system, catalyzes the activation of the vasoconstricting and proliferation-stimulating angiotensin II and breaks down the vasodilatory peptide bradykinin. It is assumed that the excess supply of angiotensin II (due to the deletion polymorphism of the angiotensin-converting enzyme gene) contributes to endothelial dysfunction and in this way promotes the onset and progression of atherosclerosis. The aim of this study was to test whether the presence of the deletion allele of the angiotensin-converting enzyme gene predisposes a more rapid systemic progression of a preexisting peripheral arterial disease. To this end, the course of disease was surveyed for an average of 5 years in 97 patients who were angiotensin-converting enzyme gene-typed and suffered from a stable stage II peripheral arterial disease according to Fontaine. These patients did not suffer from an additional coronary artery disease, a cerebrovascular disease, or other serious illness. A local progression in the periphery or a systemic progression in the coronary or cerebrovascular areas was regarded as study endpoints. Of the patients, 49.5% showed an atherosclerosis progression during the surveillance period. With II-carriers, a progression was registered in 42.1% and with DD carriers, progression was seen in 59.4%. D/I allele frequencies were seen in patients with progression at a level of 0.60/0.40 vs 0.55/0.45 for patients without progression. The average duration of disease in stable stage II (before progression appeared) amounted to 108 +/- 14 months for II carriers, 88 +/- 8 months for ID carriers, and 92 +/- 11 months for DD carriers (p = 0.21). Based on these findings, the deletion polymorphism of the angiotensin-converting enzyme gene is not an independent risk factor for progression of atherosclerosis in patients with peripheral arterial disease.

Genetic aspects of stroke: human and experimental studies

As one of the leading causes of death within both the developed and developing world, stroke is a worldwide problem. Risk factors can be identified and controlled at the level of lifestyle changes; however, genetic components of stroke have yet to be identified. The identification of such genetic components is critical in the understanding, diagnosis, and treatment of stroke in the future. This review focuses on the genetic determinants of stroke in both human and experimental systems. Mendelian disorders, candidate genes, and twin studies provide evidence for a strong genetic component of stroke. Genome-wide scanning in both human and animal models has led to the identification of regions of the genome that contain genes for stroke susceptibility and sensitivity. Animal models of stroke allow for environmental control and genetic homogeneity, not possible within a human population, and therefore are essential for the dissection of this complex, multifactorial disorder. Future genetic and genomic strategies and their role in ultimate causative gene identification are discussed.

Genetic determinants of vascular reactivity

Blood pressure is controlled by a complex combination of processes that influence cardiac output and peripheral vascular resistance. Multiple genes potentially influence each parameter involved in the control of blood pressure, and individuals with the same blood pressor level do not necessarily have the same genotype at relevant loci, nor do individuals with the same genotype at particular loci necessarily have the same blood pressure. Nevertheless, pharmacogenetic studies of vascular reactivity will certainly allow the analysis of the mechanisms affected by genes, and lead to a better understanding of the epidemiologic observations seen in large groups of patients. Polymorphisms in the genes of the renin-angiotensin system allow definition of the "genetic profile" associated with a higher risk of cardiovascular disease, and can also be linked to significant changes in vascular reactivity in arteries isolated from patients carrying the polymorphisms.

Intima-media thickness: a new tool for diagnosis and treatment of cardiovascular risk

Increased intima-media thickness (IMT) is a non-invasive marker of early arterial wall alteration, which is easily assessed in the carotid artery by B-mode ultrasound, and more and more widely used in clinical research. Methods of IMT measurement can be categorized by two approaches: (i) measurement at multiple extracranial carotid sites in near and far walls and (ii) computerized measurement restricted to the far wall of the distal common carotid artery. Because IMT reflects global cardiovascular risk, its normal value might be better defined in terms of increased risk rather than in terms of statistical distribution within a healthy population. The available epidemiological data indicate that increased IMT (at or above 1 mm) represents a risk of myocardial infarction and/or cerebrovascular disease. Close relationships have been shown between: (i) most traditional cardiovascular risk factors; (ii) certain emerging risk factors such as lipoproteins, psychosocial status, plasma viscosity, or hyperhomocysteinemia; and (iii) various cardiovascular or organ damages such as white matter lesion of the brain, left ventricular hypertrophy, microalbuminuria or decreased ankle to brachial systolic pressure index. Thus, IMT gives a comprehensive picture of the alterations caused by multiple risk factors over time on arterial walls. Prospective primary and secondary prevention studies have also shown that increased IMT is a powerful predictor of coronary and cerebrovascular complications (risk ratio from 2 to 6) with a higher predictive value when IMT is measured at multiple extracranial carotid sites than solely in the distal common carotid artery. Therapeutic double-blind trials have shown that lipid-lowering drugs, such as resin and overall statines, and to a lesser extent antihypertensive drugs, such as calcium antagonists, may have a beneficial effect on IMT progression in asymptomatic or in coronary patients. However, methodological standardization of IMT measurement still needs to be implemented before routine measurement of IMT can be proposed in clinical practice as a diagnostic tool for stratifying cardiovascular risk in primary prevention and for aggressive treatment decision. It can be anticipated however, that the presence of increased carotid IMT in one individual with intermediate cardiovascular risk would lead to his classification into the high-risk category and thus influence the aggressiveness of risk factor modifications.

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.

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

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

Night time blood pressure and cardiovascular structure in a middle-aged general population in northern Italy: the Vobarno Study

The aim was to determine, in a cross-sectional study, the relation between structural alterations in the heart and carotid arteries, and blood pressure (BP) changes from day to night time, measured by ambulatory BP (ABP). In 225 untreated subjects (107 F, 118 M, age range 48-64 years) and 59 treated subjects (24 M, 35 F, age range 50-64), living in a small town of northern Italy (Vobarno, Brescia) carotid intima media thickness as well as the occurrence of plaque, were evaluated by ultrasound. Echocardiographic left ventricular (LV) mass was measured according to the Penn Convention. BP was determined by clinic measurement and by 24-h non-invasive ABP monitoring. Subjects were divided in two groups, according to the decrease of night time systolic BP (SBP) "dippers" (SBP decreased by at least 10% during night time) and "non-dippers" (decrease of night time SBP <10%). The intima-media thickness in the common carotid, in the carotid bifurcation, in the internal carotid artery and average intima-media thickness were significantly greater in untreated non-dippers as compared with dipper subjects (ANOVA P < 0.05). A significantly higher prevalence of plaque was observed in untreated non-dippers as compared with dippers (P = 0.002). After adjusting for age, sex, 24-h SBP, and smoking, IMT in the carotid bifurcation and average intima-media thickness remained significantly greater in non-dipper subjects (P < 0.05 for all comparisons). No significant differences in LV mass were observed between dippers and non-dipper subjects. In conclusion, in a general population of unselected middle-aged subjects, night time BP values, among other risk factors, seem to represent an important determinant of carotid wall structure.

Aspects of gene polymorphisms in cardiovascular disease: the renin-angiotensin system

The renin-angiotensin system (RAS) plays a central role in cardiovascular homeostasis. Angiotensin is the key peptide of the RAS, and exerts its influence on the heart and blood vessels both through its haemodynamic effects (via its influence on after-load and pre-load and determining coronary vasoconstriction) and through its direct cellular effects (via its actions on cell proliferation). Numerous studies in the past 10 years have demonstrated that the pharmacological inhibition of angiotensin converting enzyme (ACE), one of the two critical enzymes of the RAS, improves the outcome in patients with several cardiovascular disorders (hypertension, heart failure, ischaemic heart disease). These studies suggest a role of the RAS as a major determinant of cardiovascular risk. Recent data suggest that genetics may in turn contribute to modulating the effects of angiotensin on coronary vascular biology and ischaemia. This paper reviews the physiologic characteristics of the RAS and recent research developments related to angiotensin cell biology and pathobiology in heart disease. In particular, this review will cover the genetic aspects of RAS and their implications in cardiovascular disease.