The DD-ACE genotype and cardiovascular disease

Association of ACE*(Insertion/Deletion) Variant with the Elevated Risk of Preeclampsia Among Gestational Women

The renin-angiotensin-aldosterone system has an indispensable function in the uteroplacental circulation, placental growth, and blood pressure optimization. The angiotensin I converting enzyme (ACE) gene is a critical integrator for electrolyte balance, and water retention, along with inhibiting preeclampsia. The main goal of this pertaining study is to assess the contribution of ACE*(Ins/Del) variant with the susceptibility for preeclampsia with focus on the severity of the disease among gestational hypertensive women. This retrospective study included 225 participants [125 PE gestational women, and 100 normotensive healthy controls] matching with age, and geographical region. PE women classified into 82 early-onset PE women, accompanied with 43 late-onset PE women. Additionally, PE women categorized into 59 mild PE women, together with 66 severe PE women. The genotyping and characterization of ACE*(Ins/Del) variant were applied using the PCR technique. Our findings indicated higher frequency of the ACE*(Del/Del) genotype and ACE*(D allele) with elevated risk of preeclampsia compared to normotensive controls under recessive (OR = 2.09, and p-value = 0.007), and allelic (OR = 1.75, and p-value = 0.012) models. In addition, testing logistic regression revealed that the levels of endothelin-1 and malondialdehyde exposed significant difference for the ACE*(Del/Del) genotype among early-onset and late-onset PE women (p-value = 0.024, and 0.23, respectively). Furthermore, carriers of the ACE*(Del/Del) genotype observed statistically significant with lower sodium concentrations among severe PE women (p-value = 0.034). The ACE*(Del/Del) genotype and ACE*(D allele) were associated with increased risk preeclampsia among gestational women. Furthermore, early-onset PE and late-onset PE were correlated with endothelin-1 and malondialdehyde concentrations among Egyptian women.

Female Sex and Angiotensin-Converting Enzyme (ACE) Insertion/Deletion Polymorphism Amplify the Effects of Adiposity on Blood Pressure

The pathophysiological link between adiposity and blood pressure is not completely understood, and evidence suggests an influence of sex and genetic determinants. We aimed to identify the relationship between adiposity and blood pressure, independent of a robust set of lifestyle and metabolic factors, and to examine the modulating role of sex and Angiotensin-Converting Enzyme (ACE) insertion/deletion (I/D) polymorphisms. In the Relationship Between Insulin Sensitivity and Cardiovascular Disease (RISC) study cohort, 1211 normotensive individuals, aged 30 to 60 years and followed-up after 3.3 years, were characterized for lifestyle and metabolic factors, body composition, and ACE genotype. Body mass index (BMI) and waist circumference (WC) were independently associated with mean arterial pressure, with a stronger relationship in women than men (BMI: r=0.40 versus 0.30; WC: r=0.40 versus 0.30, both P<0.01) and in individuals with the ID and II ACE genotypes in both sexes (P<0.01). The associations of BMI and WC with mean arterial pressure were independent of age, sex, lifestyle, and metabolic variables (standardized regression coefficient=0.17 and 0.18 for BMI and WC, respectively) and showed a significant interaction with the ACE genotype only in women (P=0.03). A 5 cm larger WC at baseline increased the risk of developing hypertension at follow-up only in women (odds ratio, 1.56 [95% CI, 1.15-2.10], P=0.004) and in II genotype carriers (odds ratio, 1.87 [95% CI, 1.09-3.20], P=0.023). The hypertensive effect of adiposity is more pronounced in women and in people carrying the II variant of the ACE genotype, a marker of salt sensitivity.

Human gene polymorphisms and their possible impact on the clinical outcome of SARS-CoV-2 infection

The SARS-CoV-2 pandemic has become one of the most serious health concerns globally. Although multiple vaccines have recently been approved for the prevention of coronavirus disease 2019 (COVID-19), an effective treatment is still lacking. Our knowledge of the pathogenicity of this virus is still incomplete. Studies have revealed that viral factors such as the viral load, duration of exposure to the virus, and viral mutations are important variables in COVID-19 outcome. Furthermore, host factors, including age, health condition, co-morbidities, and genetic background, might also be involved in clinical manifestations and infection outcome. This review focuses on the importance of variations in the host genetic background and pathogenesis of SARS-CoV-2. We will discuss the significance of polymorphisms in the ACE-2, TMPRSS2, vitamin D receptor, vitamin D binding protein, CD147, glucose-regulated protein 78 kDa, dipeptidyl peptidase-4 (DPP4), neuropilin-1, heme oxygenase, apolipoprotein L1, vitamin K epoxide reductase complex 1 (VKORC1), and immune system genes for the clinical outcome of COVID-19.

Does Genetic Predisposition Contribute to the Exacerbation of COVID-19 Symptoms in Individuals with Comorbidities and Explain the Huge Mortality Disparity between the East and the West?

The elderly and patients with several comorbidities experience more severe cases of coronavirus disease 2019 (COVID-19) than healthy patients without underlying medical conditions. However, it is unclear why these people are prone to developing alveolar pneumonia, rapid exacerbations, and death. Therefore, we hypothesized that people with comorbidities may have a genetic predisposition that makes them more vulnerable to various factors; for example, they are likely to become more severely ill when infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To test this hypothesis, we searched the literature extensively. Polymorphisms of genes, such as those that encode angiotensin-converting enzyme 1 (ACE1), have been associated with numerous comorbidities, such as cardiovascular disease, hypertension, diabetes, chronic kidney disease, and obesity, and there are potential mechanisms to explain these associations (e.g., DD-type carriers have greater ACE1 activity, and patients with a genetic alpha-1 anti-trypsin (AAT) deficiency lack control over inflammatory mediators). Since comorbidities are associated with chronic inflammation and are closely related to the renin–angiotensin–aldosterone system (RAAS), these individuals may already have a mild ACE1/ACE2 imbalance before viral infection, which increases their risk for developing severe cases of COVID-19. However, there is still much debate about the association between ACE1 D/I polymorphism and comorbidities. The best explanation for this discrepancy could be that the D allele and DD subtypes are associated with comorbidities, but the DD genotype alone does not have an exceptionally large effect. This is also expected since the ACE1 D/I polymorphism is only an intron marker. We also discuss how polymorphisms of AAT and other genes are involved in comorbidities and the severity of SARS-CoV-2 infection. Presumably, a combination of multiple genes and non-genetic factors is involved in the establishment of comorbidities and aggravation of COVID-19.

Improvements of symptoms of Alzheimer`s disease by inhibition of the angiotensin system

With ageing of the global society, the frequency of ageing-related neurodegenerative diseases such as Alzheimer`s disease (AD) is on the rise worldwide. Currently, there is no cure for AD, and the four drugs approved for AD only have very small effects on AD symptoms. Consequently, there are enormous efforts worldwide to identify new targets for treatment of AD. Approaches that interfere with classical neuropathologic features of AD, such as extracellular senile plaques formed of aggregated amyloid-beta (Abeta), and intracellular neurofibrillary tangles of hyperphosphorylated tau have not been successful so far. In search for a treatment approach of AD, we found that inhibition of the angiotensin-converting enzyme (ACE) by a centrally acting ACE inhibitor retards symptoms of neurodegeneration, Abeta plaque formation and tau hyperphosphorylation in experimental models of AD. Our approach is currently being investigated in a clinical setting. Initial evidence with AD patients shows that a brain-penetrating ACE inhibitor counteracts the process of neurodegeneration and dementia. Moreover, centrally acting ACE inhibitors given in addition to the standard therapy, cholinesterase inhibition, can improve cognitive function of AD patients for several months. This is one of the most promising results for AD treatment since more than a decade.

Angiotensin-converting enzyme insertion/deletion gene polymorphism in Egyptian children with CAP: A case-control study

BACKGROUND

Community-acquired pneumonia (CAP) is a major cause of childhood morbidity and mortality worldwide. The angiotensin-converting enzyme (ACE) gene is a potential candidate gene for CAP risk.

OBJECTIVES

In this study, we aimed to investigate whether the ACE insertion/deletion (I/D) polymorphism (rs4340) could be a genetic marker for CAP susceptibility in Egyptian children, and we also measured the serum ACE level to assess its relation to such polymorphism.

METHODS

This was a prospective case-control study included 300 patients with CAP, and 300 age, gender, and ethnicity matched healthy controls. The ACE I/D polymorphism (rs4340) at intron 16 was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), while the serum ACE levels were measured by ELISA.

RESULTS

Compared to the controls subjects, the frequencies of the ACE DD genotype and D allele were overrepresented in patients with CAP (OR = 3.05; [95%CI: 2.14-4.35] for the DD genotype; P < 0.001) and (OR: 1.8; [95%CI: 1.42-2.29]; for the D allele; P < 0.01, respectively). Patients with the DD genotype had significantly higher mean serum ACE levels (45.6 ± 11.4 U/L) compared to those with ID genotype (36.5 ± 8.3 U/L) and II genotype (21.6 ± 5.7 U/L); P < 0.01, respectively.

CONCLUSION

The ACE I/D polymorphism (rs4340) may contribute to the genetic susceptibility of CAP in Egyptian children. The ACE D allele and DD genotype were associated with higher serum ACE levels among studied CAP patients.

Renin-Angiotensin System Polymorphisms and Coronary Artery Surgery Patients

The frequencies of angiotensin-converting enzyme gene insertion/deletion, angiotensinogen-M253T, and angiotensin II type 1 receptor-A1166C polymorphisms were analyzed in 105 patients undergoing coronary artery bypass grafting (group 1) and a control group of 105 non-cardiac patients (group 2). Blood samples were obtained for biochemical analyses and DNA extraction. Genotyping was performed by polymerase-chain-reaction-based restriction analysis. According to the angiotensin-converting enzyme gene insertion/deletion polymorphism, 36.3% of patients in group 1 and 30.7% in group 2 were homozygous for the DD allele. This difference was not statistically significant. Angiotensin II type 1 receptor-A1166C genotype polymorphism was also not significantly different between the groups. The results showed the angiotensinogen-M235T polymorphism to be heterogenous. The MM homozygote frequency was significantly higher in controls (72.3%), whereas 80% of the TT homozygote frequency was in the surgical group ( p = 0.001). These results show that although there were no significant differences in angiotensin-converting enzyme gene insertion/deletion and angiotensin II type 1 receptor-A1166C genotype polymorphisms between the groups, angiotensinogen-M235T polymorphism of TT homozygote frequency was significantly associated with patients undergoing coronary artery bypass surgery.

Genetic Association Between CD143 rs4340 Polymorphism and Pneumonia risk: A Meta Analysis

rs4340 polymorphism at intron 16 of the angiotensin-converting enzyme (CD143) gene was reported to repress cough reflex by reducing bradykinin and substance P levels, thus increasing the likelihood to develop pneumonia. There have been different reports regarding the correlation of CD143 rs4340 genotypes with pneumonia risk, which prompted us to perform a meta-analysis to determine the elusive association.We combined multiple keywords to identify the studies addressing the association between CD143 rs4340 genotypes and pneumonia risk covered in the EMBASE, Google Scholar, PubMed, and CNKI databases. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the risk of pneumonia. The fixed-effects model (FEM) was used.A total of 10 studies were analyzed in this quantitative analysis. We found a strong association between rs4340 single nucleotide polymorphism (SNP) and pneumonia risk using the recessive model (FEM: OR 1.33, 95% CI 1.13-1.57). A significantly increased risk was also indicated under the recessive model in Asian populations (FEM: OR 1.57, 95% CI 1.19-2.07), community-acquired pneumonia (CAP) (FEM: OR 1.31, 95% CI 1.08-1.60), and nosocomial pneumonia (NP) (FEM: OR 1.52, 95% CI 1.06-2.19).Our meta-analysis demonstrates that CD143 rs4340 polymorphism may represent a risk factor for pneumonia.

Increased risk of pneumonia associated with angiotensin-converting enzyme (CD143) rs4340 polymorphism

The study aims to investigate the genetic association between rs4340 polymorphism at intron 16 of the angiotensin-converting enzyme (CD143) gene and pneumonia predisposition. Electronic database of PubMed, Embase, and CNKI (China National Knowledge Infrastructure) was searched for the studies addressing the association between CD143 rs4340 genotypes and pneumonia risk. The odds ratio (OR) with its 95 % confidence interval (CI) was employed to estimate the association. In total, ten case-control studies, including 1239 pneumonia cases and 2400 healthy controls, met the inclusion criteria. Our results showed a significant association between rs4340 SNP and pneumonia risk using the recessive model (OR 1.43, 95 % CI 1.20-1.70). A significantly increased risk was also indicated under the recessive model in Asian populations (OR 1.63, 95 % CI 1.16-2.30), Caucasian populations (OR 1.34, 95 % CI 1.09-1.65), community-acquired pneumonia (OR 1.42, 95 % CI 1.16-1.75) rather than nosocomial pneumonia (OR 1.47, 95 % CI 0.97-2.23). However, further studies with gene-gene and gene-environmental interactions should be considered to confirm this association.

Association between the ACE insertion/deletion polymorphism and pterygium in Sardinian patients: a population based case-control study

OBJECTIVE

The purpose of the study was to examine whether the insertion (I) and/or deletion (D) polymorphism of ACE confers susceptibility to primary pterygium in Sardinian patients in a case-control study.

METHODS AND RESULTS

Polymorphism genotyping was performed by nested PCR using genomic DNA extracted from the whole peripheral blood of participants with (n=251) and without (n=260) pterygium. DD, ID and II genotype frequencies were: 48%, 39% and 13%, respectively, for patients with pterygium, and 15%, 40% and 44%, respectively, for the control group. A statistically significant difference was found between the pterygium and control groups for the ACE I/D polymorphism (p<0.001). Moreover, a statistically significant difference was found between the DD and II groups (p<0.01; OR=10.49; 95% CI 6.18 to 17.79), DD+ID versus II group (p<0.01; OR=5.23; 95% CI 3.37 to 8.13) and DD versus ID groups (p<0.01; OR=3.21; 95% CI 2.04 to 5.04).

CONCLUSIONS

Statistical analysis showed that the DD genotype is associated with an increased risk of developing pterygium, and with a good chance that the D allele may play an important role in the development of disease.

IgE-Mediated Anaphylaxis to Foods, Venom, and Drugs: Influence of Serum Angiotensin Converting Enzyme Levels and Genotype

Circulating angiotensin-II protects the circulation against sudden falls in blood pressure and is generated by the enzymatic action of angiotensin converting enzyme (ACE) on angiotensin-I. The ACE genes have 2 allelic forms, “I” and “D.” The “D” genotype has both highest angiotensin-II generation and serum ACE levels compared to “I”. 120 patients with IgE-anaphylaxis, 119 healthy controls, and 49 atopics had serum ACE levels, ACE genotype, and renin levels determined. Plasma renin levels were identical for all groups. Serum ACE levels and genotypes were similar for healthy controls (HC) and atopics, but lower in anaphylaxis (P = 0.012), with ACE genotypes also showing increased “I” genes (P = 0.009). This effect was more pronounced in subjects manifesting airway angioedema and cardiovascular collapse (AACVS) than mild cutaneous and respiratory (CRA) symptoms. AACVS was significantly associated with the presence of “I” genes. For “ID” genotype OR is 5.6, 95% CI 1.8 to 17.4, and for “II” genotype OR is 44, 95% CI 5 to 1891 within the anaphylaxis group = 0.001. The results show a difference in the genotype frequency between control and anaphylaxis, suggesting a role for the renin angiotensin system in anaphylaxis manifesting with airway angioedema and cardiovascular collapse.

Insertion/deletion polymorphism of the angiotensin-converting enzyme considerably changes postoperative outcome

STUDY OBJECTIVE

To evaluate the influence of insertion/deletion (ID) polymorphism of the angiotensin-converting enzyme (ACE) gene on clinical outcome of cardiac valve surgery.

DESIGN

Prospective, blinded observational study.

SETTING

Operating room and intensive care unit (ICU) of a university hospital.

PATIENTS

110 adult patients requiring elective cardiac valve surgery requiring cardiopulmonary bypass.

MEASUREMENTS

Patients' preoperative data (age, gender, body weight, New York Heart Association score, medication, biochemical data, and comorbid disorders), anesthetic management (blood pressure, heart rate, blood loss and transfusion, and cardiorespiratory complications and their treatment), and postoperative outcome (life-threatening complications, nosocomial infections, reintubation/reoperation, death, and duration of ICU stay and hospitalization) were recorded. ACE ID was detected by gel electrophoresis following conventional polymerase chain reaction. Patients were divided into two groups postoperatively; groups with II and non-II (ID and DD) genotypes, and group differences were analyzed.

MAIN RESULTS

Distribution of ACE ID in II, ID, and DD genotypes was 29%, 59%, and 12%, respectively. The non-II group had significantly greater postoperative blood loss and transfusion (P < 0.05), more common postoperative infections, and longer ICU stay duration than the II group (P < 0.01).

CONCLUSIONS

ACE ID polymorphism is associated with a higher incidence of postoperative complications, including postoperative infections, in patients undergoing cardiac valve surgery.

Genetic polymorphisms influence runners' responses to the dietary ingestion of antioxidant supplementation based on pequi oil (Caryocar brasiliense Camb.): a before-after study

Genes have been implicated in the levels of oxidative stress, lipids, CVD risk, immune reactivity, and performance. Pequi oil (Caryocar brasiliense) has shown anti-inflammatory and hypotensive effects, besides reducing exercise-induced DNA, tissue damages, and anisocytosis. Given that diet can interact with the human genome to influence health and disease, and because genetic variability can influence response to diet, we aim to investigate the influence of 12 gene polymorphisms on inflammatory markers, postprandial lipids, arterial pressure, and plasma lipid peroxidation of runners (N = 125), before and after 14 days of 400 mg pequi-oil supplementation, after races under closely comparable conditions. Arterial pressure was checked before races; blood samples were taken immediately after racing to perform leukogram and plateletgram, Tbars assay, lipid, and CRP dosages and genotyping. CAT, GST-M1/T1, CRP-G1059C, and MTHFR-C677T polymorphisms influenced post-pequi-oil responses in leukogram; Hp and MTHFR-C677T, in plateletgram; Hp, ACE, GSTT1, and MTHFR-A1298C, in lipid profile; MTHFR-A1298C, in C-reactive protein (CRP) levels; and Hp and MnSOD, in Tbars assay. Differences between ACE genotypes in leukogram and total cholesterol disappeared after pequi, and the same occurred for Hp and MnSOD in Tbars assay and for MTHFR-A1298C with CRP levels. Because genetic inheritance is one of the factors that drive atherosclerosis-related lipid abnormalities, results can contribute to a greater understanding of the influence of genetic polymorphisms in situations that push up free radicals. Knowledge is also expanded on how antioxidant supplementation affects an individual's genes and how athletic genetic makeup can affect the way a person responds to antioxidant supplements.

Angiotensin converting enzyme DD genotype not associated with increased risk of coronary artery disease in the Iranian population

The coronary artery disease (CAD) is of the main causes of heart failure and there is evidence supporting the association of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and the susceptibility to CAD. Therefore, the relevance of ACE polymorphism for CAD was determined in the Iranian population. 487 age-matched individuals including 224 patients with >50% angiographically established coronary stenosis and 263 healthy subjects genotyped for ACE gene I/D polymorphism by a standard method. Paraclinical characteristics including lipid profile were also determined for both groups. While the systolic (p<0.0001) and diastolic (p<0.0001) blood pressure, serum cholesterol (p<0.005) and LDL-C (p<0.05) were significantly increased in CAD patients, our results show that there was no increased risk of CAD in association with DD genotype in Iranian population. Allele frequencies were also similar in both groups. Although, we found a significant difference in ID (p<0.005) and II (p<0.05) genotype between patients and healthy subjects. The present study showed that DD genotype does not increase the CAD susceptibility in the studied Iranian population and may not be as a risk factor. Therefore, further studies together with the other polymorphisms of ACE gene may be required to determine the relation between cardiovascular disease susceptibility and ACE genetic variations in Iranian population.

Polymorphisms in the angiotensin-converting enzyme gene region predict coping styles in healthy adults and depressed patients

Dispositional coping styles are important moderators of the stress reaction and are altered in stress-related disorders like cardiovascular diseases and affective disorders. Heritability studies suggest a considerable genetic contribution to the interindividual variability in coping styles. Since the angiotensin-converting enzyme (ACE) gene has been described to be associated with the vulnerability for stress-related disorders and with altered stress hormone regulation, we investigated the ACE gene as potential candidate gene for coping styles. Five hundred forty one mentally healthy subjects and 194 patients suffering from depression participating in the Munich Antidepressant Response Signature (MARS) project were examined. Coping styles were assessed with a self-report questionnaire (German Stress Coping Questionnaire SVF78) measuring the individual coping style pattern in response to stressful situations. We genotyped 15 single nucleotide polymorphisms (SNPs) and the insertion/Deletion (I/D)-polymorphism in the ACE gene region and investigated their associations with coping styles. In healthy subjects, the highest association was observed between rs8066276, an intronic SNP of the ACE gene, and the coping factor Distraction. A further intronic SNP rs4305, not in linkage disequilibrium with rs8066276, showed an association with Devaluation/Defense. All associated copying styles can be categorized as potentially stress reducing factors (positive coping). Both SNPs were also found to be associated with positive coping styles in the patient sample; rs8066276 was associated with Devaluation/Defense, and rs4305 showed associations with Control. These results suggest that the ACE gene is involved in the development of coping strategies.

ACE gene insertion/deletion polymorphism modulates capillary permeability in hypertension

A D/D (deletion/deletion) polymorphism within the ACE (angiotensin 1-converting enzyme) gene increases the risk of microalbuminuria, a predictor of atherosclerotic vascular disease, in essential hypertension. It is unknown, however, whether this genetic profile is accompanied by disturbed macromolecular permeability of systemic capillary endothelium, possibly in the context of generalized endothelial dysfunction. In the present study, the ACE gene polymorphism was determined by PCR in 79 never-treated uncomplicated hypertensive men and 16 normotensive men as controls. Evaluation variables were TERalb (transcapillary escape rate of albumin; the 1-h decline rate of intravenous (125)I-albumin, a measure of integrity of systemic capillary endothelium), albuminuria and forearm vasodilation to intra-arterial acetylcholine, an index of NO (nitric oxide)-mediated vasomotion, in addition to a series of sensitive parameters of albumin permeation (blood pressure, metabolic status and smoking habits). Analyses were done by comparing D/D homozygotes with grouped I/D (insertion/deletion) and I/I (insertion/insertion) subjects. TERalb was higher in D/D hypertensives, who had higher albuminuria, more frequent microalbuminuria and comparable forearm responsiveness to intra-arterial acetylcholine. Fasting glucose and insulin, insulin sensitivity, 24-h blood pressure, smoking habits and metabolic parameters did not differ between the two groups. TERalb and urine albumin values were positively associated in the hypertensive subjects. In conclusion, ACE D/D homozygosis, independently of several confounding factors, associates with higher TERalb in men with essential hypertension. This may reflect noxious genetic influences on systemic vascular permeability, a critical control mechanism for atherogenesis in the absence of grossly impaired NO-mediated arteriolar responsiveness. The parallel behaviour of TERalb and albuminuria suggests some shared genetically mediated determinant of renal and systemic microvascular abnormalities in hypertension.

Pharmacogenetic association of the angiotensin-converting enzyme insertion/deletion polymorphism on blood pressure and cardiovascular risk in relation to antihypertensive treatment: the Genetics of Hypertension-Associated Treatment (GenHAT) study

BACKGROUND

Previous studies have reported that blood pressure response to antihypertensive medications is influenced by genetic variation in the renin-angiotensin-aldosterone system, but no clinical trails have tested whether the ACE insertion/deletion (I/D) polymorphism modifies the association between the type of medication and multiple cardiovascular and renal phenotypes.

METHODS AND RESULTS

We used a double-blind, active-controlled randomized trial of antihypertensive treatment that included hypertensives > or =55 years of age with > or =1 risk factor for cardiovascular disease. ACE I/D genotypes were determined in 37 939 participants randomized to chlorthalidone, amlodipine, lisinopril, or doxazosin treatments and followed up for 4 to 8 years. Primary outcomes included fatal coronary heart disease (CHD) and/or nonfatal myocardial infarction. Secondary outcomes included stroke, all-cause mortality, combined CHD, and combined cardiovascular disease. Fatal and nonfatal CHD occurred in 3096 individuals during follow-up. The hazard rates for fatal and nonfatal CHD and the secondary outcomes were similar across antihypertensive treatments. ACE I/D genotype group was not associated with fatal and nonfatal CHD (relative risk of DD versus ID and II, 0.99; 95% CI, 0.91 to 1.07) or any secondary outcome. The 6-year hazard rate for fatal and nonfatal CHD in the DD genotype group was not statistically different from the ID and II genotype group by type of treatment. No secondary outcome measure was statistically different across antihypertensive treatment and ACE I/D genotype strata.

CONCLUSIONS

ACE I/D genotype group was not a predictor of CHD, nor did it modify the response to antihypertensive treatment. We conclude that the ACE I/D polymorphism is not a useful marker to predict antihypertensive treatment response.

Angiotensin-converting enzyme, sleep-disordered breathing, and hypertension

The angiotensin-converting enzyme (ACE) gene insertion/deletion polymorphism influences ACE activity, cardiovascular risk, blood pressure, and possibly the risk of developing Alzheimer's dementia. We explored the association of the insertion/deletion polymorphism with sleep-disordered breathing (SDB) and hypertension in 1,100 subjects of the Wisconsin Sleep Cohort. The polymorphism did not influence body mass index or the occurrence of SDB, but was dose-dependently associated with blood pressure. Interestingly, SDB and the insertion/deletion polymorphism interacted significantly to modulate blood pressure independently of age, sex, ethnicity, and body mass index. Most specifically, the association of the deletion allele with hypertension was most pronounced in subjects with mild to moderate degrees of sleep apnea (5 < or = apnea-hypopnea index < or = 30). We hypothesize that in the absence of SDB the effect of the deletion allele alone may not be sufficient to increase blood pressure. At severe levels of SDB, the effect of sleep apnea on blood pressure overwhelms any association of the deletion allele with hypertension and occurs independent of any ACE gene genotype.

Genomic polymorphisms in sepsis

OBJECTIVE

This article aims to review all relevant genetic polymorphism studies that may contribute to the pathogenesis of sepsis with emphasis on polymorphisms of the innate immunity, pro- and anti-inflammatory cytokines, and coagulation mediators.

DATA SOURCE

Published articles reporting on studies of associations between genetic polymorphisms, sepsis, septic shock, and other relevant infectious disease models.

DATA ANALYSIS

Research into the pathogenesis of sepsis has led to the development of many potential therapeutic strategies. Several therapeutic agents and treatment modalities have been shown to decrease mortality rates in large, prospective, and randomized clinical trials. However, although these advances have resulted in improved survival for certain patient populations, the overall mortality rate for septic patients remains high. With the rapid development of molecular and genetic techniques, substantial interests have developed in using genomic information to define disease-mediating genetic variants in sepsis. Combined with microarray technology, it is anticipated in the near future that one will be able to tailor drug selection and dosage and predict outcome by correlating genetic profile with disease presentation. Numerous genetic association studies in sepsis have already been reported and more are likely to be published.

CONCLUSIONS

Although studies examined in this review are of small heterogeneous populations, the identification of strong associations between certain genetic polymorphisms and increased mortality rate or susceptibility to severe sepsis is intriguing and supports further research using this approach. The establishment of these associations does not equal causation, and further research is required in both genetic and molecular aspect of sepsis.

[Gene polymorphism in intensive care patients. Is the course of disease predetermined?]

Molecular biology has revolutionized medicine by increasing our understanding of the pathophysiological mechanisms of disease and the ability to assess genetic risk. Individual differences in disease manifestation and course in intensive care medicine often cannot be explained by known phenotypic risk factors alone. Recent data suggest an association between specific genotypes and the risk of adverse clinical outcomes. This includes inflammatory responses (i.e. TNF-alpha, Il-10), infectious diseases such as pneumonia or meningitis, sepsis, ARDS, as well as the mortality of critically injured patients (polytrauma, severe brain trauma). Continued identification of such allotypes and haplotypes may not only provide insight as to why the response to treatment varies amongst individuals in the intensive care unit, but also may potentially decrease morbidity and mortality through improved risk assessment and the administration of prophylactic therapy.

Polymorphism in gene coding for ACE determines different development of myocardial fibrosis in rats

In humans, the effect of angiotensin-converting enzyme (ACE) gene polymorphisms in cardiovascular disease is still controversial. In the rat, a microsatellite marker in the ACE gene allows differentiation of the ACE gene polymorphism among strains with different ACE levels. We tested the hypothesis that this ACE gene polymorphism determines the extent of cardiac fibrosis induced by isoproterenol (Iso) in the rat. We used a male F2generation (homozygous LL and BB ACE genotypes determined by polymerase chain reaction) derived from two rat strains [Brown-Norway (BB) and Lewis (LL)] that differ with respect to their plasma ACE activities. For induction of left ventricular (LV) hypertrophy (LVH) and cardiac fibrosis, rats were infused with Iso (5 mg·kg–1·day–1) or saline (control) for 10 days and euthanized at day 1 after the last injection. The interstitial collagen volumetric fraction (ICVF), collagen I, and fibronectin content, but not collagen III content, were significantly higher in the homozygous BB rats than in homozygous LL rats. Differences in metalloprotease (MMP)-9, but not in MMP-2 activities as well as in cardiac cell proliferation, were also detected between LL and BB rats treated with Iso. LV ACE activity was higher in BB rats than LL rats and correlated with ICVF ( r = 0.61, P < 0.002). No changes were observed in plasma ACE activities, ANG II plasma or LV levels, plasma renin activity, and ACE and ANG II type 1 receptor (AT1R) mRNA levels in the LV of rats with the two different ACE polymorphisms. Iso induced a similar degree of LVH [assessed by an increase in LV weight 100 per body weight, LV-to-right ventricle (RV) ratio, and LV protein content] in LL and BB rats. We concluded that rats in the F2generation with high plasma ACE activity developed more fibrosis but to a similar degree of LVH compared with rats with low plasma ACE activity.

Smoking-dependent effects of the angiotensin-converting enzyme gene insertion/deletion polymorphism on blood pressure

BACKGROUND

Studies on the role of the angiotensin-converting enzyme (ACE) gene in the development of hypertension have yielded conflicting results. Recent studies suggested that this gene might have smoking-dependent effects on the development of cardiovascular disease.

OBJECTIVE

To study the relationship between the ACE insertion/deletion (I/D) polymorphism, blood pressure and risk of hypertension in current, former and non-smokers in a population-based cohort.

METHODS

We included 2412 non-smokers, 2794 former smokers and 1508 current smokers, all participants in the Rotterdam Study. In each group, we assessed the relationship between the ACE I/D polymorphism, systolic (SBP) and diastolic (DBP) blood pressures and risk of hypertension. Mean blood pressures and prevalence of hypertension were compared between carriers and non-carriers of the D allele. All analyses were adjusted for age, sex, body mass index, diabetes mellitus, high-density lipoprotein cholesterol, total cholesterol and use of antihypertensive medication.

RESULTS

In non-smokers and former smokers, blood pressure and the risk of hypertension did not differ significantly between genotypes. In smokers, we found a significant increase in SBP in DD carriers (139.6 +/- 22.8 mmHg) compared with II carriers (136.0 +/- 22.7 mmHg) (P = 0.04). No effect of ACE genotype was observed for DBP. The risk of hypertension was significantly increased in smokers who carried one [odds ratio (OR) 1.4, 95% confidence interval (CI) 1.0 to 1.9; P = 0.05] or two (OR 1.5, 95% CI 1.1 to 2.2; P = 0.02) copies of the D allele.

CONCLUSIONS

The D allele of the ACE polymorphism is associated with a significantly increased SBP and risk of hypertension in smokers. Our study underlines the importance of gene-environment interactions in the study of candidate genes for hypertension.

The ACE gene I/D polymorphism is not associated with the blood pressure and cardiovascular benefits of ACE inhibition

The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene might have consequences for the risks of vascular diseases. We examined the ACE genotype and the effects of a perindopril-based blood pressure-lowering regimen on macrovascular events, dementia, and cognitive decline among hypertensive and nonhypertensive patients with a history of cerebrovascular disease. ACE I/D genotypes were measured in 5688 of 6105 individuals with previous stroke or transient ischemic attack who participated in the PROGRESS trial. The DD genotype was significantly (P<0.0001) less frequent in Asian subjects (Chinese and Japanese, 14.7%) than in non-Asian subjects (32.0%). Controlling for racial background, there were no associations between ACE genotypes and cerebrovascular disease history or cardiovascular risk factors, including baseline blood pressure. The ACE genotype was not associated with the long-term risks of stroke, cardiac events, mortality, dementia, or cognitive decline; neither did the ACE genotype predict the blood pressure reduction associated with the use of the ACE inhibitor perindopril. Similarly, there was no evidence that the ACE genotype modified the relative benefits of ACE inhibitor-based therapy over placebo. This study provides no evidence that in patients with cerebrovascular disease, knowledge of ACE genotype is useful for predicting either the risk of disease or the benefits of perindopril-based blood pressure-lowering treatment.

PAI-1 4G/5G and ACE I/D gene polymorphisms and the occurrence of myocardial infarction in patients on intermittent dialysis

BACKGROUND

Myocardial infarction (MI) is a leading cause of death, particularly in high-risk settings such as uraemia, in which it is not yet known to what extent genetic factors contribute to the overall risk of MI. We have prospectively evaluated the effect of plasminogen activator inhibitor-1 (PAI-1) 4G/5G and angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphisms on the occurrence of MI in uraemics.

METHODS

All patients undergoing intermittent dialysis in an Italian district were enrolled as subjects. From the same area, 1307 individuals served as controls. Genomic DNA was obtained and ACE I/D and PAI-1 4G/5G gene polymorphisms were determined. After a baseline evaluation, patients were followed for 28.8+/-9.8 months. MIs and other causes of death were recorded.

RESULTS

A total of 461 patients (417 on haemodialysis and 44 on peritoneal dialysis) were investigated. At entry, their mean age was 58.2+/-16.2 years and dialytic age was 82+/-69 months. Genotype frequencies were not different between controls and uraemics and, in the latter group, between patients with or without cardiovascular diseases at baseline evaluation. During the follow-up, 22 fatal and 16 non-fatal MIs were recorded (mean incidence 1.99 and 1.45%/year, respectively). The adjusted risk of fatal and total MI was related to the presence at entry of a history of MI [hazard ratios (HR) 4.3; 95% confidence interval (CI) 1.5-12.0 and HR 6.8; 95% CI: 3.3-14.0, respectively] and to the PAI-1 4/4 genotype (HR 2.8; 95% CI 1.2-6.9 and HR 2.1; 95% CI 1.1-4.2, respectively).

CONCLUSIONS

In end-stage renal disease, PAI-1 4G/5G gene polymorphism may have a significant role in the occurrence of fatal and non-fatal MI.

Cardiac hypertrophy and microvascular deficit in kinin B2 receptor knockout mice

Experimental and clinical evidence suggests kinin involvement in adaptive myocardial growth. Kinins are growth-inhibitory to cardiomyocytes. Knockout of kinin B2 receptor (B2R) signaling causes dilated and failing cardiomyopathy in 129/J mice, and a 9-bp deletion polymorphism of human B2R is associated with reduced receptor expression and exaggerated left ventricular growth response to physical stress. We reasoned that genetic background and aging may significantly influence the impact of B2R mutation on cardiac phenotype. The theory was challenged in C57BL/6 mice, a strain that naturally differs from the 129/J strain, carrying 1 instead of 2 renin genes. C57BL/6 B2R knockouts (B2R-KO) showed higher blood pressure and heart rate levels (P<0.05) compared with wild-type controls (WT) at all ages examined. At 12 months, left ventricular contractility and diastolic function were mildly altered (P<0.05) and histological and morphological analyses revealed ventricular hypertrophy and cardiomyocyte enlargement in B2R-KO (P<0.01). Reparative fibrosis was enhanced by 208% and capillary density reduced by 38% (P<0.01). Functional and structural alterations induced by B2R deletion in C57BL/6 mice were less severe than those reported previously in the 129/J strain. We conclude that interaction of B2R signaling with other genetic determinants influences aging-related changes in myocardial structure and function. These findings may help us understand the role of kinins in the development of cardiac failure.

Pharmacogenomics of primary hypertension--the lessons from the past to look toward the future

A number of recent reviews have addressed the issue of the pharmacogenomics of primary hypertension and related complications by considering the data on the genotype-drug response relationship. Here we mainly discuss the methodological aspects of this issue, trying to integrate 'traditional' clinical and experimental pathophysiology and therapy-pharmacology with the 'new' genetics. Such integration is indispensable to: a). define the appropriate 'context' (genetic background, environment, age, gender, phase of hypertension, previous therapy etc.) in which a given genotype-drug response relationship should be tested (it is indeed likely that many discrepancies among published data originate from context's interference); b). assign the correct clinical meaning to the results obtained by statistics and functional genetics methodologies; c). define a novel clinical entity caused by a disease favoring allele, alone or in combination with other alleles, with a consistent clinical picture, prognosis and responsiveness to the appropriate drug; d). estimate the size of the population target amenable to benefit from a therapeutic intervention developed according to the pharmacogenomics' principles; e). develop a novel drug that selectively interferes with the sequence of events triggered by the genetic mechanism(s) underlying the clinical entity. Peculiar to this strategy is to look for consistency among findings gathered from different 'contexts' after having properly accounted for the context's dependency of the results.

Angiotensin-converting enzyme gene polymorphism interacts with left ventricular ejection fraction and brain natriuretic peptide levels to predict mortality after myocardial infarction

OBJECTIVES

The goal of this study was the exploration of the associations between the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and post-myocardial infarction (MI) outcomes, especially any interaction with the accepted clinical prognostic markers brain natriuretic peptide (BNP) and left ventricular ejection fraction (LVEF).

BACKGROUND

The ACE gene I/D polymorphism has been implicated in the development of MI, hypertension, and left ventricular hypertrophy. We examined the association of ACE I/D and prognosis after acute MI.

METHODS

Patients incurring acute MI were genotyped for the ACE I/D polymorphism. Clinical data included assays of neurohormones, radionuclide ventriculography, and mortality over a mean 2.6 years of follow-up.

RESULTS

Patients (n = 978) had a mean age of 62.1 years, and 78% were male. Overall genotype frequencies were II 23.2%, ID 49.5%, and DD 27.3%. Chi-square analysis revealed an association between the ACE D allele and death after MI (88 of 103 who died were DD or ID; p < 0.05), with an odds ratio for mortality of 8.03 (95% confidence interval, 2.16 to 29.88). Patients with the DD genotype had higher (p < 0.05) plasma BNP, N-terminal BNP (N-BNP), and endothelin-1 levels within 96 h after MI than grouped ID/II patients. Multivariate analysis indicated ACE genotype, age, and previous MI were independent predictors of death (p < 0.05). Patients with an ACE D allele in combination with either a lower than median LVEF or greater than median BNP had a higher mortality (p < 0.001 and p < 0.025, respectively) than the risk associated with the D allele itself.

CONCLUSIONS

Angiotensin-converting enzyme genotyping may provide additional prognostic information in patients after MI in combination with the proven utility of LVEF, plasma BNP, and N-BNP measurements.

ACE and alpha-adducin polymorphism as markers of individual response to diuretic therapy

Renin-angiotensin system reactivity and the constitutive capacity of the renal tubule to reabsorb sodium play a role in the individual response to diuretic therapy; therefore we evaluated the blood pressure (BP) response to hydrochlorothiazide in 87 never-treated individuals with mild essential hypertension, according to ACE gene I/D and alpha-adducin Gly460Trp polymorphism. These genotypes where chosen because previous data showed their interaction in determining the BP response to salt probably was the result of their involvement in the activation of the renin-angiotensin system (ACE) and in the constitutive capacity of the kidney to reabsorb sodium (alpha-adducin) (treatment for 2 months). BP was measured after 3 run-in visits and after the first and second months of treatment by means of a standardized procedure. Data were analyzed by ANOVA, t test, and multivariate ANOVA for repeated measures (covarying for gender, age, and body mass index). Although basal mean BP (MBP) was similar in the different ACE and alpha-adducin genotypes, patients carrying at least one I allele of ACE and one 460Trp allele of alpha-adducin had the largest MBP decrease with treatment (12.7+/-1.9 mm Hg), the effect of the combination of genotypes being additive but not epistatic. These patients had an odds ratio of 15.75 of being a responder to hydrochlorothiazide compared with patients with Gly460Gly+DD, with the least MBP decrease (3.4+/-1.7 mm Hg). Alpha-adducin and ACE I/D polymorphism may be useful to predict the interindividual degree of response to hydrochlorothiazide; the analysis of the combination of the 2 genotypes increases the accuracy of the prediction of response to the drug.

Primer on medical genomics. Part VI: Genomics and molecular genetics in clinical practice

An important milestone in medical science is the recent completion of a "working draft" of the human genome sequence. The identification of all human genes and their regulatory regions provides the framework to expedite our understanding of the molecular basis of disease. This advance has also formed the foundation for a broad range of genomic tools that can be applied to medical science. These developments in global gene and gene product analysis as well as targeted molecular genetic testing are destined to change the practice of modern medicine. Despite these exciting advances, many practicing clinicians perceive that the role of molecular genetics, especially that of genomics, is confined primarily to the research arena with little current clinical applicability. The aim of this article is to highlight advances in DNA/RNA-based methods of susceptibility screening, disease diagnosis and prognostication, and prediction of treatment outcome in regard to both drug toxicity and response as they apply to various areas of clinical medicine.

Deletion allele of the angiotensin-converting enzyme gene as a risk factor for pneumonia in elderly patients

PURPOSE

Aspiration due to an age-related reduction in cough is a major cause of pneumonia in elderly persons. Because the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene (ACE) has been associated with the cough reflex, we studied whether this genetic polymorphism was also associated with the risk of pneumonia.

SUBJECTS AND METHODS

We studied 1011 elderly inpatients (221 men and 790 women, mean [+/- SD] age of 82 +/- 7 years) in a long-term care hospital. The association between the ACE I/D polymorphism and the incidence of pneumonia (defined using specific criteria that included radiographic abnormalities) was assessed during an 8-month period that excluded the winter. Data were analyzed using proportional hazards models, with adjustment for age, sex, and other potential confounders.

RESULTS

During follow-up, 87 cases (9%) of pneumonia occurred, 38 of which were fatal. The ACE DD allele (vs. ID + II) was associated with an increased risk of pneumonia (relative risk [RR] = 2.9; 95% confidence interval [CI]: 1.7 to 4.8, P < 0.001) and fatal pneumonia [RR = 4.4; 95% CI: 2.1 to 9.0; P < 0.0001).

CONCLUSIONS

The ACE D allele is an independent risk factor for pneumonia in elderly persons.

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.

The platelet Pl(A2) and angiotensin-converting enzyme (ACE) D allele polymorphisms and the risk of recurrent events after acute myocardial infarction

Chromosome 17q21-23 harbors genes for platelet glycoprotein IIIa and angiotensin-converting enzyme (ACE), which are polymorphic for alleles Pl(A2) and ACE "D." These alleles have been independently and often associated with ischemic coronary artery disease (CAD). We sought to determine if the Pl(A2) and ACE D polymorphisms were risk factors for recurrent coronary events. In the Cholesterol And Recurrent Events (CARE) trial, 4,159 men and women with documented myocardial infarction (MI) were randomized to receive either placebo or pravastatin, and were followed prospectively for 5 years. Pl(A) and ACE genotypes were determined in 767 patients: 385 cases who had experienced a recurrent primary event (death due to coronary disease or nonfatal MI), and 382 age- and gender-matched controls. In patients receiving placebo, the Pl(A1,A2) genotype conferred a relative risk (RR) of 1.38 (confidence intervals [CI] 1.04 to 1.83; p = 0.028; adjusted RR = 1.32, CI = 0.99 to 1.76; p = 0.058]) for the primary end point. Compared with the placebo group, pravastatin reduced the excess RR of coronary disease death and recurrent MI in the Pl(A1,A2) patient population by 31% (p = 0.06). The ACE D allele appeared to have modestly additive effects on the Pl(A1,A2) risk. Among the Pl(A1,A2) patients, pravastatin had little effect on the risk of recurrent events with the ACE II genotype, but reduced the adjusted RR from 1.42 (placebo) to 0.58 for ACE ID patients, and from 1.56 (placebo) to 0.83 for ACE DD. The Pl(A1,A2) genotype was associated with an excess of recurrent coronary events in patients after MI who did not receive pravastatin, and the ACE D allele added to this risk. These data suggest that it would be important to perform a larger study to address the potential role of these genotypes in therapeutic decision making.