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

Mathematical modelling of the influence of ACE I/D polymorphism on blood pressure and antihypertensive therapy

The angiotensin-converting enzyme (ACE) gene (ACE) insertion/deletion (I/D) polymorphism raises the possibility of personalising ACE inhibitor therapy to optimise its efficiency and reduce side effects in genetically distinct subgroups. However, the extent of its influence among these subgroups is unknown. Therefore, we extended our computational model of blood pressure regulation to investigate the effect of the ACE I/D polymorphism on haemodynamic parameters in humans undergoing antihypertensive therapy. The model showed that the dependence of blood pressure on serum ACE activity is a function of saturation and therefore, the lack of association between ACE I/D and blood pressure levels may be due to high ACE activity in specific populations. Additionally, in an extended model simulating the effects of different classes of antihypertensive drugs, we explored the relationship between ACE I/D and the efficacy of inhibitors of the renin-angiotensin-aldosterone system. The model predicted that the response of cardiovascular and renal parameters to treatment directly depends on ACE activity. However, significant differences in parameter changes were observed only between groups with high and low ACE levels, while different ACE I/D genotypes within the same group had similar changes in absolute values. We conclude that a single genetic variant is responsible for only a small fraction of heredity in treatment success and its predictive value is limited.

ACE Gene I/D Polymorphism and Cardiometabolic Risk Factors: A Cross Sectional Study of Rural Population

The D allele has been identified as being linked to cardiovascular disease since the discovery of an insertion/deletion (I/D) polymorphism in the ACE gene, this polymorphism has been found to have significant associations with a variety of cardiovascular risk factors. Recent findings indicate a rising prevalence of metabolic disorders among rural populations in developing nations. Research on health matters has been predominantly focused on urban populations, with relatively less attention given to their rural counterparts Hence, the present study attempts to estimate the prevalence of ACE gene I/D polymorphism and explore its association with various cardiovascular risk factors among Rural Yadav population from India. In the present study, 207 (Male 47, Female 160) members of the Yadav community participated in the cross-sectional study. All the socio-demographic factors, somatometric (anthropometric) variables, and the intravenous blood was collected and Physiological (blood pressure), and biochemical (fasting glucose and lipid profile) parameters were measured as recommended by the American Heart Association, allele-specific PCR of the ACE gene I/D polymorphism was carried out, the PCR products were genotyped on 2% agarose gel Electrophoresis and ACE gene polymorphism was analysed for its association with various cardiovascular risk factors. Among the analysed individuals, 34 (16.4%) were found to have the II genotype, 58 (28.0%) had the ID genotype, and 115 (55.6%) had the DD genotype. The allele frequency of the I allele was found to be 0.31, and the frequency of the D allele was 0.69. The frequency of the DD genotype was found to be significantly higher among individuals with high TC, high TG, and low non-HDL levels (p value < 0.05). When considered collectively, the findings of this study are consistent with the hypothesis that the DD genotype of ACE polymorphism represents a correlation with cardiovascular disease risk factors in this population.

Association between ACE I/D genetic polymorphism and the severity of coronary artery disease in Vietnamese patients with acute myocardial infarction

Background

The severity of coronary artery disease is a prognostic factor for major adverse cardiovascular events in patients diagnosed with acute myocardial infarction. ACE I/D polymorphism is one of the genetic factors that may affect the severity of coronary artery disease. This study aimed to investigate the association between ACE I/D genotypes and the severity of coronary artery disease in patients with acute myocardial infarction.

Materials and methods

A single-center, prospective, observational study was conducted at the Department of Cardiology and Department of Interventional Cardiology, Cho Ray Hospital, Ho Chi Minh City, Vietnam from January 2020 to June 2021. All participants diagnosed with acute myocardial infarction underwent contrast-enhanced coronary angiography. The severity of coronary artery disease was determined by Gensini score. ACE I/D genotypes were identified in all subjects by using the polymerase chain reaction method.

Results

A total of 522 patients diagnosed with first acute myocardial infarction were recruited. The patients' median Gensini score was 34.3. The II, ID, and DD genotype rates of ACE I/D polymorphism were 48.9%, 36.4%, and 14.7%, respectively. After adjusting for confounding factors, multivariable linear regression analysis showed that the ACE DD genotype was independently associated with a higher Gensini score compared with the II or ID genotypes.

Conclusion

The DD genotype of the ACE I/D polymorphism was associated with the severity of coronary artery disease in Vietnamese patients diagnosed with first acute myocardial infarction.

Angiotensin-converting enzyme gene insertion/deletion polymorphism and hypertension disease

Background: The renin-angiotensin system (RAS), which is important for controlling haemostasis in the body, can increase the development of essential hypertension (HTN). Various surveys have shown that ACE I/D polymorphism that influences ACE activity, a key component of RAS, has been known to be associated with the risk of HTN. The goal of this study was to investigate the correlation between ACE (I/D) polymorphism and HTN.Methods: Blood samples were obtained from 102 patients and 104 healthy individuals. The two groups were matched by age and sex. Informed consent was prepared for the study. The demographic data were collected using a questionnaire. White blood cells (WBCs) and then DNA were extracted from whole blood. After this, the PCR test was performed using specific primers. PCR products were examined using 1% agarose gel. Individuals with genotype II having a band of 490 bp, ID two band of 490 bp and 190 bp, and individuals with DD genotype, have a band in region 190 bp.Results: The average age of the patients was 52.7 ± 7.5 years. A significant difference was seen in the distribution of DD, II and I/D genotypes of ACE polymorphism between the essential hypertensive patients (44.1, 10.8, and 45.1%) and their ethnically matched healthy control (61.5, 3.8, and 24.6%, respectively). Our study showed an increased risk of disease in people with II genotype in comparison to ID and DD genotypes (0.46 (0.1-1.75) and 0.26 (0.05-0.94), respectively).Conclusions: The present study demonstrated that ACEI/D polymorphism is characterised with greater risk of essential HTN in the Lorestan province. II genotype increased the relative risk of essential HTN in the population. In the future, more investigations with more samples size are recommended for the better study of genetic factors in hypertensive patients.

The Association of Angiotensin-converting Enzyme I/D and Angiotensinogen M235T Polymorphism Genes with Essential Hypertension: A Meta-analysis

Objective:  Essential or primary hypertension in developing countries has become a major problem. Recent hypertension-related research has revealed susceptibility genes in genome-wide association studies. Several studies have associated angiotensin converting enzyme (ACE) I/D and angiotensinogen (AGT) M235T polymorphisms with essential hypertension, but results have been inconsistent. This meta-analysis aimed to clarify the association of AGT and ACE polymorphisms with the risk of primary hypertension. Methods: PubMed, Embase database, Medline, Goggle Scholar, Scopus.com, as well portal Garuda (www.garuda.ristekdikti.go.id) and Cochrane were used to retrieve all publications from 2006-2020 relating risk factors for hypertension with ACE I/D and AGT M235T polymorphisms. The meta-analysis was conducted from January –April 2020. All association studies were identified and data extracted from each study. Revman 5.3 software was used for meta-analysis to estimate odds ratios (OR) after extracting data and evaluating the quality of the enrolled studies. Results: A total of 27 studies (totaling 5,105 patients and 5196 controls) were identified. The overall effect suggested ACE I/D was significantly associated with primary hypertension (OR: 95%CI=1.51[1.29-1.77], p=0.004). There was no association between AGT M235T with risk of essential hypertension. Conclusion: This meta-analysis found significant association between ACE I/D gene polymorphisms with primary hypertension susceptibility. However, the AGT M235T gene had no association with the risk of primary hypertension. The Adrenoreceptor-beta/Renin Angiotensin System (ADRB/RAS) A allele should be considered a risk factor for essential hypertension.  

Association between angiotensinogen (AGT), angiotensin-converting enzyme (ACE) and angiotensin-II receptor 1 (AGTR1) polymorphisms and COVID-19 infection in the southeast of Iran: a preliminary case-control study

BACKGROUND

The COVID-19 pandemic remains an emerging public health crisis with serious adverse effects. The disease is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV--2) infection, targeting angiotensin-converting enzyme-2 (ACE2) receptor for cell entry. However, changes in the renin-angiotensin system (RAS) balance alter an individual's susceptibility to COVID-19 infection. We aimed to evaluate the association between AGT rs699 C > T, ACE rs4646994 I/D, and AGTR1 rs5186 C > A variants and the risk of COVID-19 infection and the severity in a sample of the southeast Iranian population.

METHODS

A total of 504 subjects, including 258 COVID-19 positives, and 246 healthy controls, were recruited. Genotyping of the ACE gene rs4646994, and AGT rs699, and AGTR1 rs5186 polymorphisms was performed by polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP), respectively.

RESULTS

Our results showed that the II genotype of ACE rs4646994 and the I allele decreased the risk of COVID-19 infection. Moreover, we found that the TC genotype and C allele of AGT rs699 increased the risk of COVID-19 infection. The AGTR1 rs5186 was not associated with COVID-19 infection. Also, we did not find any association between these polymorphisms and the severity of the disease. However, we found a significantly higher age and prevalence of diabetes and hypertension in patients with severe disease than a non-severe disease.

CONCLUSIONS

These findings suggest that ACE rs4646994 and AGT rs699 polymorphisms increase the risk of COVID-19 infection in a southeast Iranian population.

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.

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

•

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

•

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

•

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

•

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

Background

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

Materials and methods

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

Results

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

Conclusion

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

Association Between Polymorphism of the Angiotensin I Converting Enzyme Gene and Hypertension in Turkish Type II Diabetic Patients

It has been suggested that an insertion/deletion (I/D) polymorphism in intron 16 of the angiotensin converting enzyme (ACE) gene may be associated with essential hypertension. The aim of this study was to examine the association between ACE I/D polymorphism with blood pressure level and hypertension status in Turkish type 2 diabetic subjects. Hundred and seven hypertensive (78 female, 29 male) and 132 normotensive type 2 diabetic subjects (73 female, 59 male) and 138 sex and age matched control subjects (87 female, 51 male) without diabetes and hypertension were included into the study. The I/D polymorphism was determined by polymerase chain reaction (PCR). There were no statistically difference in genotypic and allelic frequencies of the ACE I/D polymorphism between the hypertensive and normotensive diabetic patients and control subjects. Also no significant differences was detected in systolic and diastolic blood pressure among three different genotypes. ACE I/D polymorphism does not seem to play an important role in the development of hypertension in Turkish type 2 diabetic subjects, but prospective studies may show an association between ACE gene polymorphism and the development of hypertension in diabetic subjects.

Genetic Determinants of Dyslipidemia in African-Based Populations: A Systematic Review

Identification of genetic/genomic factors contributing to dyslipidemia is of great interest to prevention and reduction of the onset and burden of cardiovascular diseases in Africa. This systematic review summarizes available data on genetic variants associated with dyslipidemia in populations within Africa. A PubMed and EMBASE database search was conducted to identify all studies published until June 2018 on genetic susceptibility to dyslipidemia in African-based populations, excluding familial hypercholesterolemia. All studies on genetic predispositions of dyslipidemia and respecting the preestablished inclusion criteria were included in this systematic review. Because of high heterogeneity, the data were summarized narratively. Twenty-two studies investigated mostly the targeted genetic variants. A total of 51 polymorphisms in 28 susceptibility genes to dyslipidemia have been associated with a particular trait in the African populations, and through variable effects. Most polymorphisms investigated in Northern Africa seemed to have consistent effects on increasing the level of low-density lipoprotein cholesterol (LDL-C), total cholesterol, and triglycerides in patients with diabetes, myocardial infarction, coronary artery disease, and metabolic syndrome. By contrast, only Ser447Ter and C49620T variants were associated with increased LDL-C in sub-Saharan Africa. Despite few studies available in this context in the literature, certain genetic variants were consistently associated with dyslipidemia especially in Northern Africa as highlighted in this analysis. Further data, particularly from genome-wide association studies, would help establish an African-specific reference for genetic susceptibility markers of dyslipidemia.

Effects of angiotensin converting enzyme gene polymorphism on hypertension in Africa: A meta-analysis and systematic review

BACKGROUND

Hypertension is dramatically increasing in Africa with evidence of increased severity and resistance to treatment. Although angiotensin converting enzyme gene polymorphism is associated with higher prevalence of hypertension, the evidence is inconclusive on its influence on the emerging pattern in Africa. This meta-analysis is conducted to pool the available evidence to inform future research and interventions.

METHODS

Articles published through May 2018 were systematically searched in PubMed, Scopus and EMBASE databases. Studies were assessed for inclusion by two independent researchers. Six models were used to assess the effect of angiotensin converting enzyme deletion-insertion gene polymorphism. Heterogeneity and publication bias were tested and sensitivity analysis was carried out. Odds ratio and 95% confidence intervals were measured for pooled effect. Both random effect and fixed effect models were used, whilst the frequency of DD, II and DI genotypes were computed and compared.

RESULT

Patients with D allele were 1.49 times more likely to develop essential hypertension compared with patients who carry the I allele (OR:1.49; CI:1.07, 2.07). Similarly, patients who had homozygous co-dominance genotype DD (i.e., DD vs II) were at a 2.17 times higher risk of essential hypertension compared to the co-dominant genotype II (OR:2.17, CI:1.79, 3.18), dominant model (I.e., DD+ID vs II) (OR:1.48; CI:1.03, 2.12), and recessive model (OR:1.64; CI:1.03, 2.61). On subgroup analysis, participants from Sub-Saharan Africa were more genetically susceptible to hypertension compared to their North Africa counterparts. There was no publication bias found, but there was high to moderate heterogeneity.

CONCLUSION

ACE I/D polymorphism is associated with essential hypertension in Africa in the allele contrast model, as well as the dominant, recessive and homozygous codominance model. On subgroup analysis, ACE I/D was associated with essential hypertension in patients from Sub-Saharan Africa but not in North Africa. A future large scale study, which includes different ethnic groups, is recommended.

Focus on increased serum angiotensin-converting enzyme level: From granulomatous diseases to genetic mutations

Angiotensin I-converting enzyme (ACE) is a well-known zinc-metallopeptidase that converts angiotensin I to the potent vasoconstrictor angiotensin II and degrades bradykinin, a powerful vasodilator, and as such plays a key role in the regulation of vascular tone and cardiac function. Increased circulating ACE (cACE) activity has been reported in multiple diseases, including but not limited to granulomatous disorders. Since 2001, genetic mutations leading to cACE elevation have also been described. This review takes advantage of the identification of a novel ACE mutation (25-IVS25 + 1G > A) in two Belgian pedigrees to summarize current knowledge about the differential diagnosis of cACE elevation, based on literature review and the experience of our centre. Furthermore, we propose a practical approach for the evaluation and management of patients with elevated cACE and discuss in which cases search for genetic mutations should be considered.

Angiotensin-Converting Enzyme Gene Polymorphism in Children with Idiopathic Nephrotic Syndrome, Effect on Biopsy Findings

OBJECTIVE

Angiotensin converting enzyme (ACE) converts angiotensin I into angiotensin II. The ACE gene shows an I/D polymorphism, which correlates with ACE concentrations. The aim of this study is to evaluate the distribution of the ACE I/D genotype in children with idiopathic nephrotic syndrome (INS) and healthy controls and study the effect of this polymorphism on clinical and pathologic findings.

METHODS

ACE gene I/D polymorphism of 104 patients with INS and 119 controls were determined.

RESULTS

The DD, ID, and II genotypes were found in 58.7%, 22.1%, and 19.2% of the patients, and in 79.8%, 2.5%, and 17.6% of controls, respectively (p > 0.05). The ID genotype was seen more frequently in patients resistant to treatment.

CONCLUSION

The observed differences with previous reports suggest the influence of the genetic background on disease course. The ACE I/D gene polymorphism's role seems to be more important in renal disease progression than susceptibility.

The relationship between angiotensin-converting enzyme (ACE) insertion (I) / deletion (D) polymorphism, serum ACE activity and bone mineral density (BMD) in older Chinese

Objective:

In this study, we set out to investigate the relationship between angiotensin-converting enzyme (ACE) I/D polymorphism, serum ACE activity and bone mineral density (BMD) in older Chinese.

Methods:

A standardized, structured, face-to-face interview was performed to collect demographic information. BMD was measured using dual-energy X-ray absorptiometry (DXA). I/D genotypes of ACE were determined by polymerase chain reaction (PCR) amplification. Serum ACE activity was determined photometrically by a commercially available kinetic kit. Multiple linear regression analysis was used to examine the relationship between ACE I/D polymorphism, serum ACE activity and BMD.

Results:

A total of 1567 males and 1760 females were selected for analyzing the relationship between ACE I/D polymorphism and BMD. There was no significant difference in spine BMD, total hip BMD and femur neck BMD among different ACE I/D genotypes both in males and females. A total of 1699 males and 1739 females were selected for analyzing the relationship between serum ACE activity and BMD. There was also no significant difference in spine BMD, total hip BMD and femur neck BMD among different serum ACE activity groups both in males and females.

Conclusion:

There was no relationship between ACE I/D polymorphism, serum ACE activity and BMD in older Chinese.

Familial aggregation of albuminuria and arterial hypertension in an Aboriginal Australian community and the contribution of variants in ACE and TP53

Background

Aboriginal Australians are at high risk of cardiovascular, metabolic and renal diseases, resulting in a marked reduction in life expectancy when compared to the rest of the Australian population. This is partly due to recognized environmental and lifestyle risk factors, but a contribution of genetic susceptibility is also likely.

Methods

Using results from a comprehensive survey of one community (N = 1350 examined individuals), we have tested for familial aggregation of plasma glucose, arterial blood pressure, albuminuria (measured as urinary albumin to creatinine ratio, UACR) and estimated glomerular filtration rate (eGFR), and quantified the contribution of variation at four candidate genes (ACE; TP53; ENOS3; MTHFR).

Results

In the subsample of 357 individuals with complete genotype and phenotype data we showed that both UACR (h² = 64%) and blood pressure (sBP h² = 29%, dBP, h² = 11%) were significantly heritable. The ACE insertion-deletion (P = 0.0009) and TP53 codon72 polymorphisms (P = 0.003) together contributed approximately 15% of the total heritability of UACR, with an effect of ACE genotype on BP also clearly evident.

Conclusions

While the effects of the ACE insertion-deletion on risk of renal disease (especially in the setting of diabetes) are well recognized, this is only the second study to implicate p53 genotype as a risk factor for albuminuria - the other being an earlier study we performed in a different Aboriginal community (McDonald et al., J Am Soc Nephrol 13: 677-83, 2002). We conclude that there are significant genetic contributions to the high prevalence of chronic diseases observed in this population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0396-2) contains supplementary material, which is available to authorized users.

The Genetic Determinants of Renal Impairment Following Cardiac Surgery

Cardiac surgery is frequently performed, and acute renal dysfunction is a common adverse event following this procedure. Cardiac surgery-related renal injury independently predicts longer hospital stays and greater rates of morbidity and mortality. Although much work has been completed toward better understanding of this phenomenon, the state of knowledge concerning surgery-related renal injury remains limited. Currently, there is no effective paradigm to identify patients who are at risk for this condition; the specific mechanisms of renal injury during surgery are incompletely understood; and few therapies exist to prevent or treat this phenomenon. To better understand this common clinical problem, recent research has focused on the importance of genetic variability within the physiological and patho-physiological systems that underlie renal dysfunction following cardiac surgery. Emphasizing the importance of using genetics to elucidate molecular mechanisms of this disease, this article reviews the current literature on genetic polymorphisms and post cardiac surgery-related renal dysfunction.

Lack of change in serum angiotensin-converting enzyme activity during the menstrual cycle

Introduction. The Deletion (D) rather than Insertion (I) variant of the angiotensin-converting enzyme (ACE) gene is associated with higher circulating ACE activity. Meanwhile, coronary risk rises with the menstrual nadir in oestrogen levels, exogenous oestrogen reduces serum ACE activity (with a greater reduction the higher the baseline ACE activity), and pharmacological reduction in ACE activity is cardioprotective. Alterations in coronary risk associated with the menstrual cycle may thus be mediated through (genotype-dependent) changes in ACE activity. We have examined this hypothesis.

Materials and methods. Twenty-three healthy female subjects (12 II, 11 DD genotype) were studied. None were taking oral contraceptive agents. Blood was assayed for oestrogen, follicle stimulating hormone (FSH), luteinising hormone (LH), progesterone and ACE activity every three days throughout their menstrual cycle. Results ACE activity was unrelated to oestrogen, FSH or LH during the menstrual cycle, irrespective of ACE genotype.

Conclusions. The increase in myocardial ischaemia during low oestrogen phases of the menstrual cycle does not appear mediated through a fall in serum ACE activity.

Polymorphisms of the renin-angiotensin system genes in Brazilian patients with lupus nephropathy

Genetic polymorphisms of the renin-angiotensin system (RAS) has been associated with cardiovascular events and the progression of nephropathy in several diseases. The objective of this study was to evaluate a possible association of the genetic polymorphisms of RAS with the development and/or progression of lupus nephritis in a Brazilian population. Seventy-five SLE patients with lupus nephropathy (LN group) were compared to 72 SLE patients without LN (SLE group) and 65 healthy individuals (CONTROL group), of sex and ethnic matched, in a Brazilian population sample. Mean global follow-up was 9 + 6 years for lupus without nephropathy and 11 + 7 years for lupus nephropathy. Following the extraction of genomic DNA from the leukocytes in the peripheral blood, angiotensin converting enzyme (ACE I/D), angiotensinogen (AGT M235T) and angiotensin II type 1 receptor (AGTR1 A1166C) genotypes were determined by the polymerase chain reaction.

No significant difference of ACE, AGT and AGTR1 genotypes distribution between groups was observed in this study. There was no significant association between the variables of the RAS genotypes and the presence of hypertension in SLE. However, an increased frequency of DD genotype (ACE I/D) was observed in SLE patients with LN who progressed to CRF compared to healthy controls (DD 60%, DI 26.7%, II 13.3% versus 27.7%, 60% and 12.3%, respectively; x2 = 6.299, P = 0.0429). In the population studied, there was no influence of the RAS genetic polymorphisms in the development of lupus nephropathy, but the progression to CRF was associated with ACE DD polymorphism.

The effect of angiotensin-converting enzyme polymorphism on hemodynamic response to endotracheal intubation in hypertensive patients

Endotracheal intubation elicits a hemodynamic response associated with increased heart rate and blood pressure that is influenced by the angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) genetic polymorphism which may be of importance also for the pressure response to anesthesia. A total of 337 patients underwent abdominal surgery in general anesthesia and 16% were D/D-homozygotes, 45% were I/D heterozygotes and 39% of the patients were I/I homozygotes. Before surgery most patients were in treatment for arterial hypertension. Systolic and diastolic pressure, heart rate and concentrations of catecholamines in blood were determined before and after induction of anesthesia and for up to 10 minutes following endotracheal intubation. Anesthesia decreased blood pressure and for patients presenting ID and DD, blood pressure and heart rate reached similar levels but compared to II-homozygotes, D-carriers demonstrated significantly higher levels for systolic pressure and heart rate before and after intubation (p < 0.05). The blood levels of catercholamines were similar in the three genotype groups. The incidence of ECG-determined myocardial ischemia was higher in D-allele carriers compared to I-allele homozygotes (DD 22%, ID 25% vs. II 5%). In response to anesthesia and intubation and independent of sympathetic nervous activity, D-allele carriers for ACE polymorphism increased blood pressure response and higher risk for development of cardiovascular complications compared to patients homozygous for the I-allele.

Molecular genetics of essential hypertension

Hypertension is a major public health problem in the developing as well as in developed countries due to its high prevalence and its association with coronary heart disease, renal disease, stroke, peripheral vascular disease, and related disorders. Essential hypertension (EH) is the most common diagnosis in this disease, suggesting that a monocausal etiology has not been identified. However, a number of risk factors associated with EH have also been identified such as age, sex, demographic, environmental, genetic, and vascular factors. Recent advances in molecular biological research had achieved clarifying the molecular basis of Mendelian hypertensive disorders. Molecular genetic studies have now identified mutations in several genes that cause Mendelian forms of hypertension in humans. However, none of the single genetic variants has emerged from linkage or association analyses as consistently related to the blood pressure level in every sample and in all populations. Besides, a number of polymorphisms in candidate genes have been associated with differences in blood pressure. The most prominent candidate has been the polymorphisms in the renin-angiotensin-aldosterone system. In total, EH is likely to be a polygenic disorder that results from inheritance of a number of susceptibility genes and involves multiple environmental determinants. These determinants complicate the study of blood pressure variations in the general population. The complex nature of the hypertension phenotype makes large-scale studies indispensable, when screening of familial and genetic factors was intended. In this review, recent genetic studies exploring the molecular basis of EH, including different molecular pathways, are highlighted.

Correlation of renin angiotensin system (RAS) candidate gene polymorphisms with response to Ramipril in patients with essential hypertension

Background:

The renin-angiotensin system (RAS) is an important facet of blood pressure regulation physiology. Treatment of essential hypertension targets the RAS using Angiotensin Converting Enzyme Inhibitors (ACEIs). However, ACEIs are not uniformly effective and show inter-individual pharmacodynamic variations.

Aim:

To assess the correlation between genetic polymorphisms in the genes coding for RAS components (angiotensin converting enzyme (ACE I/D), α-adducin (ADD1) and β₁-adrenoreceptor (β1-ADR)) and response to Ramipril.

Materials and Methods:

We recruited 120 patients with essential hypertension who were administered Ramipril monotherapy initially, followed by combination therapy, if needed, based on their responses. Relationship between genotypes of the three candidate genes and decrease in the blood pressure (BP) was analyzed.

Results:

One hundred and six patients were evaluable at the end of the study period and 21 different genotypes were observed among them. Seven of them were classified as responders after 8 weeks and at the end of 12 weeks, an additional 77 (72.64%) were deemed responders. 19/22 non-responders were treated with combination therapy and 7/19 (36.84%) showed a response to the same. There was a significant difference between the proportions of responders and non-responders among the genotypes of the ADD1 and β1-ADR genes (P = 0.005 and 0.003, respectively). The best predictors of response to Ramipril 5 mg daily were the II/GG/SS, II/TG/SS, II/GG/SG, ID/GG/SS, ID/GG/SG and ID/TT/SS and DD/GG/SS; II/GG/GG, II/TT/SG, ID/TG/SG, ID/TT/SG, DD/GG/SG and DD/GG/GG were moderately predictive and II/TT/SS, II/TG/GG, ID/TG/GG, DD/TG/SG and DD/TG/GG were poorly predictive of response.

Discussion:

Variable responses to Ramipril may be the result of genetic factors.

Conclusion:

Pre-prescription genotyping may help individualize treatment.

Angiotensin-converting enzyme insertion/deletion polymorphism, 24-h blood pressure profile and left ventricular hypertrophy in hypertensive individuals: a cross-sectional study

Background

The absence of nocturnal blood pressure dipping (ND) identified by 24-h ambulatory blood pressure monitoring (ABPM) correlates with a worse cardiovascular prognosis. The renin–angiotensin system influences blood pressure levels and the occurrence of target organ damage (TOD). Thus, the aim of this study was to correlate the angiotensin-converting enzyme gene (ACE) insertion/deletion (I/D) polymorphism with the 24-h blood pressure profile and TOD in hypertensive individuals.

Methods

155 non-diabetic hypertensive individuals on antihypertensive treatment underwent ABPM. Peripheral blood samples were drawn for biochemistry and genetic analysis of the ACE I/D polymorphism by polymerase chain reaction. ND was defined as ≥10 % differences in the mean systolic blood pressure (BP) during wakefulness and sleep.

Results

There were no differences in clinical or biochemical variables or TOD in respect to ND status, except for higher BP levels during sleep (p < 0.001) in non-dippers. There was significant difference in the prevalence of left ventricular hypertrophy (LVH) between ACE genotypes (II: 13.0 %; ID: 34.1 %; DD: 46.5 %; p value = 0.024) with an increased risk in carriers of the DD genotype (OR = 5.80; IC 95 % 1.50–22.44; p value = 0.011). Carriers of the D allele had higher systolic BP during wakefulness and by ABPM (p < 0.05), higher left ventricular mass (117.3 ± 50.0 vs. 100.3 ± 25.7; p value = 0.017) and higher prevalence of LVH (37.4 vs. 12.5 %; OR = 4.14; 95 % IC: 1.17–14.65; p value = 0.028), compared to the II genotype.

Conclusions

The DD genotype is associated with a higher prevalence of LVH. The presence of the D allele appears to be associated with higher mean 24-h and wake systolic BP measured by ABPM in hypertensive patients under antihypertensive treatment.

Angiotensin-converting enzyme genotype is not a significant genetic risk factor for idiopathic nephrotic syndrome in Croatian children

AIM

The association of the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism with idiopathic nephrotic syndrome (INS) is controversial. Only scarce information on European populations is available. The aim of the study was to investigate the distribution of the ACE gene I/D polymorphism and its impact on INS in children from Croatia.

MATERIALS AND METHODS

Ninety-five children with INS were investigated: 30 with minimal change disease (MCD), 35 with mesangial proliferative glomerulonephritis (MesPGN) and 30 with focal segmental glomerulosclerosis (FSGS). The control group consisted of 73 healthy adults. ACE gene was analyzed using the PCR method. The results were correlated with clinical features, renal morphology and response to immunosuppresive therapy.

RESULTS

There was no correlation of ACE genotype with gender, age of the disease onset, level of proteinuria, presence of hematuria or hypertension, and GFR at onset of the disease. No statistically significant differences in ACE genotype or allele frequencies between the controls and whole group of patients, MCD group, MesPGN group, FSGS group, steroid sensitive (SS) patients, steroid resistant (SR) patients, as well as each other, were found, although DD genotype tended to be more frequent in FSGS patients, SR patients, and frequent relapsers. Among 11 children treated with cyclophosphamide the D allele was significantly higher among non-responders (p = 0.003).

CONCLUSION

DD genotype is not a genetic risk factor for acquiring INS nor significant phenotype modifier regarding to clinical and pathohistological picture and response to steroids in Croatian children. The potential application of ACE genotyping in predicting cyclophosphamide response deserves further investigation.

Angiotensin-converting enzyme gene polymorphisms and hypertension in occupational noise exposure in Egypt

BACKGROUND

The gene-environment interaction in the pathogenesis of hypertension has not been extensively studied in occupational noise.

OBJECTIVES

The aim of this study was to determine the relationship between noise and hypertension in Egyptian workers, the interaction of angiotensin-converting enzyme (ACE) gene polymorphisms as modifiers, and the possible relationship between noise hearing impairment and hypertension.

METHODS

Study subjects were divided into two groups depending on noise exposure level. The control group (n = 161) was exposed to noise intensity <85 dB and the exposed group (n = 217) was exposed to noise intensity ≧85 dB. A polymerase chain reaction was used to differentiate the various genotypes of ACE insertion/deletion (I/D) and ACE G2350A.

RESULTS

Noise significantly increased the likelihood of hypertension. Carriers of the genotypes AG, GG, and DD were vulnerable to hypertension on noise exposure. No association between hypertension and hearing impairment or noise-induced hearing loss (NIHL) was found.

CONCLUSION

Our results support the association between ACE gene polymorphisms and occurrence of hypertension in noise-exposed workers.

Renin-angiotensin-aldosterone system polymorphisms and 5-year mortality in survivors of acute myocardial infarction: a report from the Osaka Acute Coronary Insufficiency Study

This study sought to evaluate whether genetic variants in the renin-angiotensin-aldosterone system (RAAS) have an impact on long-term mortality after acute myocardial infarction (AMI) in the percutaneous coronary intervention (PCI) era. We investigated the impacts of individual and combinations of 4 major RAAS genetic variants, angiotensinogen (AGT) T1311C, angiotensin-converting enzyme (ACE) insertion/deletion (I/D), angiotensin 2 type 1 receptor A1166C, and aldosterone synthase T4660C on 5-year mortality in 3149 post-AMI patients using multivariate Cox regression analysis. The predictive accuracy of all possible RAAS genetic combinations was evaluated using Cox regression analysis, and the best combination that affected prognosis was determined based on the minimal Akaike Information Criterion. There were 220 deaths during a median follow-up of 4.9 years. Independent analyses of any single RAAS variant did not show significant impacts on 5-year mortality. However, analyses in combination revealed that absence of both AGT CC genotype and ACE D allele was associated with lower 5-year mortality (log-rank P = 0.005). Patients with at least either of the AGT CC or ACE D allele had increased mortality with adjusted hazard ratios of 2.07 (95% confidence interval 1.18-3.65, P = 0.012), compared with those with neither the AGT CC nor ACE D allele. Among the 4 RAAS genetic variants examined, a combination of AGT and ACE polymorphisms was associated with 5-year mortality after AMI.

Gender specific association of RAS gene polymorphism with essential hypertension: a case-control study

Renin-angiotensin system (RAS) polymorphisms have been studied as candidate risk factors for hypertension with inconsistent results, possibly due to heterogeneity among various genetic and environmental factors. A case-control association study was conducted to investigate a possible involvement of polymorphisms of three RAS genes: AGT M235T (rs699), ACE I/D (rs4340) and G2350A (rs4343), and AGTR1 A1166C (rs5186) in essential hypertensive patients. A total of 211 cases and 211 controls were recruited for this study. Genotyping was performed using PCR-RFLP method. The genotype and allele distribution of the M235T variant differed significantly in hypertensives and normotensives (OR-CI = 2.62 (1.24–5.76), P = 0.006; OR-CI = 0.699 (0.518–0.943), P = 0.018), respectively. When the samples were segregated based on sex, the 235TT genotype and T allele were predominant in the female patients (OR-CI = 5.68 (1.60-25.10), P = 0.002; OR-CI = 0.522 (0.330–0.826), P = 0.005) as compare to the male patients (OR-CI = 1.54 (1.24–5.76), P = 0.34; OR-CI = 0.874 (0.330–0.826), P = 0.506), respectively. For ACE DD variant, we found overrepresentation of “I”-allele (homozygous II and heterozygous ID) in unaffected males which suggest its protective role in studied population (OR-CI = 0.401 (0.224–0.718); P = 0.0009). The M235T variant of the AGT is significantly associated with female hypertensives and ACE DD variant could be a risk allele for essential hypertension in south India.

Association of angiotensin-converting enzyme and angiotensin-converting enzyme-2 gene polymorphisms with essential hypertension in the population of Odisha, India

BACKGROUND

Hypertension is a serious health issue worldwide and essential hypertension, which includes 90-95% of the cases, is influenced by both genetic and environmental factors. Identification of these factors may help in control of this disease. The Insertion/Deletion (I/D) polymorphism in Angiotensin-Converting Enzyme (ACE) gene and rs2106809 (C > T) polymorphism in Angiotensin-Converting Enzyme 2 (ACE2) gene have been reported to be associated with essential hypertension in different populations.

AIM

To investigate the association of ACE I/D and ACE2 rs2106809 polymorphisms with essential hypertension in the population of Odisha, an eastern Indian state.

SUBJECTS AND METHODS

A total of 246 hypertensives (159 males and 87 females) and 274 normotensives (158 males and 116 females) were enrolled in the study. Detailed anthropometric data, tobacco, alcohol and food habits were recorded and 2 ml of venous blood was collected for biochemical and genetic analysis.

RESULTS

The DD genotype of ACE and TT genotype of ACE2 were significantly high among female hypertensives, while T allele of ACE2 was linked to male hypertensives. In the male population, alcohol was also identified as a potential risk factor.

CONCLUSION

Among females, ACE I/D and ACE2 rs2106809 polymorphisms, while among males, ACE2 rs2106809 polymorphism and alcohol consumption are associated with essential hypertension in the study population.

Gene-environment interactions of selected pharmacogenes in arterial hypertension

Hypertension affects approximately 1 billion people worldwide. Owing to population aging, hypertension-related cardiovascular burden is expected to rise in the near future. In addition to genetic variants influencing the blood pressure response to antihypertensive drugs, several genes encoding for drug-metabolizing or -transporting enzymes have been associated with blood pressure and/or hypertension in humans (e.g., ACE, CYP1A2, CYP3A5, ABCB1 and MTHFR) regardless of drug treatment. These genes are also involved in the metabolism and transport of endogenous substances and their effects may be modified by selected environmental factors, such as diet or lifestyle. However, little is currently known on the complex interplay between environmental factors, endogenous factors, genetic variants and drugs on blood pressure control. This review will discuss the respective role of population-based primary prevention and personalized medicine for arterial hypertension, taking a pharmacogenomics' perspective focusing on selected pharmacogenes.

A study on the polymorphisms of the renin-angiotensin system pathway genes for their effect on blood pressure levels in males from Algeria

INTRODUCTION

Several studies have assessed the relationship between blood pressure (BP) and polymorphisms within the genes encoding angiotensinogen (AGT), angiotensin II type 1 receptor (AT1R) and angiotensin-converting enzyme (ACE). However, considering the relatively large discrepancy in frequency and impact of these variants between ethnic groups and populations, still unavailable data from Algerian population are needed.

OBJECTIVE

Our purpose is to evaluate the association between the AGT M235T, AT1R +1166A/C and ACE I/D polymorphisms and variations in systolic (SBP), diastolic (DBP) and pulse pressure (PP) values.

METHODS

The associations with BP were assessed in a representative sample of 115 male subjects free of coronary heart disease (CHD). The AGT M235T, AT1R +1166A/C and ACE I/D polymorphisms were determined by PCR-ASO and PCR-RFLP analysis, respectively.

RESULTS

We showed no associations between the AGT M235T, AT1R +1166A/C nor the ACE I/D polymorphisms with variations in BP values. However, concerning the ACE I/D polymorphism, subjects carrying the ACE I allele tended to have higher SBP (+4.1 mmHg) and PP values (+3.2 mmHg) than DD subjects (adjusted p = 0.087 and p = 0.102, respectively).

CONCLUSION

The ACE I/D polymorphism needs further investigation in a larger Algerian study, especially concerning its putative impact on SBP and PP.

Angiotensin-converting enzyme insertion/deletion polymorphism and risk of myocardial infarction in an updated meta-analysis based on 34993 participants

The association between angiotensin-converting enzyme insertion/deletion (ACE I/D) polymorphism and risk of myocardial infarction (MI) has been extensively studied. However, the results were in controversy. This study aimed to explore the association between ACE I/D polymorphism and risk of MI by using a meta-analysis. We retrieved the following databases to indentify eligible studies: Medline, Embase, ISI, VIP, CBM and Wan Fang database. The latest update was 10th May, 2012. Odds ratio and 95% confidence interval (95% CI) were used to present the strength of the association. A total of 40 case-control studies with 34993 participants were included. Overall, D allele of ACE I/D polymorphism was significantly associated with an increased risk of MI in genetic comparison models (OR (95% CI): 1.41 (1.22-1.64) for DD vs. II; 1.11 (1.01-1.21) for ID vs. II; 1.23 (1.10-1.37) for D carriers vs. II; 1.28 (1.15-1.43) for DD vs. I carriers and 1.06 (1.02-1.10) for D carriers vs. I carriers). Subgroup analyses, according to ethnicities and countries of participants also indicated that D allele was significantly associated with an increased risk of MI in Asians (especially for Chinese) and Caucasians (especially for English, French, Germans and Italians) (OR (95% CI) of DD vs. ID+II: 2.11 (1.65-2.70) for Asians and 1.15 (1.05-1.27) for Caucasians). In conclusion, this meta-analysis indicated that D allele of ACE I/D polymorphism was a possible risk factor for MI incidence for both Asians and Caucasians.

The role of the renin-angiotensin-aldosterone system in preeclampsia: genetic polymorphisms and microRNA

The compensatory alterations in the rennin-angiotensin-aldosterone system (RAAS) contribute to the salt-water balance and sufficient placental perfusion for the subsequent well-being of the mother and fetus during normal pregnancy and is characterized by an increase in almost all the components of RAAS. Preeclampsia, however, breaks homeostasis and leads to a disturbance of this delicate equilibrium in RAAS both for circulation and the uteroplacental unit. Despite being a major cause for maternal and neonatal morbidity and mortality, the pathogenesis of preeclampsia remains elusive, where RAAS has been long considered to be involved. Epidemiological studies have indicated that preeclampsia is a multifactorial disease with a strong familial predisposition regardless of variations in ethnic, socioeconomic, and geographic features. The heritable allelic variations, especially the genetic polymorphisms in RAAS, could be the foundation for the genetics of preeclampsia and hence are related to the development of preeclampsia. Furthermore, at a posttranscriptional level, miRNA can interact with the targeted site within the 3'-UTR of the RAAS gene and thereby might participate in the regulation of RAAS and the pathology of preeclampsia. In this review, we discuss the recent achievements of genetic polymorphisms, as well as the interactions between maternal and fetal genotypes, and miRNA posttranscriptional regulation associated with RAAS in preeclampsia. The results are controversial but utterly inspiring and attractive in terms of potential prognostic significance. Although many studies suggest positive associations with genetic mutations and increased risk for preeclampsia, more meticulously designed large-scale investigations are needed to avoid the interference from different variations.

ACE insertion/deletion (I/D) polymorphism and diabetic nephropathy

CONTEXT

Angiotensin converting enzyme (ACE) gene encodes ACE, a key component of renin angiotensin system (RAS), plays an important role in blood pressure homeostasis by generating the vasoconstrictor peptide angiotensin II.

EVIDENCE ACQUISITIONS

Directory of Open Access Journals (DOAJ), Google Scholar, Pubmed (NLM), LISTA (EBSCO) and Web of Science have been searched.

RESULTS

The presence of ACE insertion/deletion (I/D) polymorphism affects the plasma level of ACE. ACE DD genotype is associated with the highest systemic and renal ACE levels compared with the lowest ACE activity in carriers of II genotype.

CONCLUSIONS

In this review focus has been performed on the study of ACE I/D polymorphism in various populations and its influence on the risk of onset and progression of diabetic nephropathy. Also, association between ACE I/D polymorphism and response to ACE inhibitor and angiotensin II receptor antagonists will be reviewed. Further, synergistic effect of this polymorphism and variants of some genes on the risk of development of diabetic nephropathy will be discussed.

Angiotensin-converting enzyme deletion allele is beneficial for the longevity of Europeans

The human angiotensin converting enzyme (ACE) gene is one of the most investigated candidate genes for cardiovascular diseases (CVD), but the understanding of its role among the elderly is vague. Therefore, this study focuses at: (a) testing the association of ACE polymorphism with CVD risk factors among the elderly, and (b) detecting the possible unequal distribution of ACE genotypes between senescent and younger segments of the European populations. The association of ACE I/D polymorphism with CVD health status [hypertension (HT), obesity, dislypidemia] in 301 very old subjects (88.2 ± 5 years; F/M = 221/80) was tested by means of logistic regression analysis. The meta-analysis of D allele frequency in general vs. elderly (80+ years) groups was conducted using all publicly available data for European populations comprising both age cohorts. Multiple multinomial logistic regression revealed that within this elderly sample, age (younger olds, 80-90 years), female sex (OR = 3.13, 95% CI = 1.59-6.19), and elevated triglycerides (OR = 2.53, 95% CI = 1.29-4.95) were positively associated with HT, while ACE polymorphism was not. It was also established that the DD genotype was twice as high in 80+ cohort compared to general population of Croatia (p < 0.00001). This trend was confirmed by the meta-analysis that showed higher D allele frequencies in olds from nine of ten considered European populations (OR = 1.19, 95% CI = 1.08-1.31). The data in elderly cohort do not confirm previously reported role of ACE DD genotype to the development of HT. Moreover, meta-analysis indicated that ACE D allele has some selective advantage that contributes to longevity in majority of European populations.

Between candidate genes and whole genomes: time for alternative approaches in blood pressure genetics

Blood pressure has a significant genetic component, but less than 3% of the observed variance has been attributed to genetic variants identified to date. Candidate gene studies of rare, monogenic hypertensive syndromes have conclusively implicated several genes altering renal sodium balance, and studies of essential hypertension have inconsistently implicated over 50 genes in pathways affecting renal sodium balance and other functions. Genome-wide linkage scans have replicated numerous quantitative trait loci throughout the genome, and over 50 single nucleotide polymorphisms (SNPs) have been replicated in multiple genome-wide association studies. These studies provide considerable evidence that epistasis and other interactions play a role in the genetic architecture of blood pressure regulation, but candidate gene studies have limited scope to test for epistasis, and genome-wide studies have low power for both main effects and interactions. This review summarizes the genetic findings to date for blood pressure, and it proposes focused, pathway-based approaches involving epistasis, gene-environment interactions, and next-generation sequencing to further the genetic dissection of blood pressure and hypertension.

The Alu polymorphism of angiotensin I converting enzyme (ACE) and atherosclerosis, incident chronic diseases and mortality in an elderly Chinese population

OBJECTIVE

We examined the contribution of ACE I/D polymorphism in a large Chinese population to four year change in ankle-brachial index (ABI), development of cardiovascular diseases and mortality in a prospective study adjusting for many confounding factors.

METHOD

Data are drawn from a longitudinal study of 4000 community-living men and women aged 65 years and over, for which detailed information regarding lifestyle, chronic diseases, body mass index (BMI), ABI measurements and ACE polymorphisms were documented at baseline. During the fifth year of follow up, incident cardiovascular diseases, ABI, and mortality were documented, and related to ACE genotype adjusting for age, smoking, alcohol, dietary intake, physical activity, body mass index, and use of ACE inhibitors.

RESULTS

Women with the D/D genotype had the greatest reduction in mean ABI after adjusting for confounding factors. D/D genotype was also more common among women who developed hypertension or myocardial infarction. However D/D genotype was associated with mortality only in men.

CONCLUSION

In a Chinese elderly population, ACE polymorphism may be considered "deleterious" to longevity, the D/D genotype being associated with mortality, the atherosclerotic process, hypertension and myocardial infarction. There are gender differences in the relationship between D/D genotype and cardiovascular diseases and mortality may not be mediated by the atherosclerotic process alone.

The genetic architecture of Alzheimer's disease: beyond APP, PSENs and APOE

Alzheimer's disease (AD) is a complex disorder with a clear genetic component. Three genes have been identified as the cause of early onset familial AD (EOAD). The most common form of the disease, late onset Alzheimer's disease (LOAD), is, however, a sporadic one presenting itself in later stages of life. The genetic component of this late onset form of AD has been the target of a large number of studies, because only one genetic risk factor (APOE4) has been consistently associated with the disease. However, technological advances allow new approaches in the study of complex disorders. In this review, we discuss the new results produced by genome wide association studies, in light of the current knowledge of the complexity of AD genetics.

The ACE I/D polymorphism in US adults: limited evidence of association with hypertension-related traits and sex-specific effects by race/ethnicity

BACKGROUND

The insertion/deletion (I/D) variant (rs4646994) of the angiotensin I-converting enzyme (ACE) gene is one of the most studied polymorphisms in relation to blood pressure and essential hypertension in humans. The evidence to date, however, on an association of this variant with blood pressure-related outcomes has been inconclusive.

METHODS

We examined 5,561 participants of the Third National Health and Nutrition Examination Survey (NHANES III), a population-based and nationally representative survey of the United States, who were ≥20 years of age and who self-identified as non-Hispanic white, non-Hispanic black, or Mexican American. Within each race/ethnicity, we assessed genetic associations of the I/D variant with systolic blood pressure (SBP), diastolic blood pressure (DBP), and hypertension, as well as genotype-sex interactions, in four genetic models (additive, dominant, recessive, and codominant).

RESULTS

The frequency of the I/D variant differed significantly by race/ethnicity (P = 0.001). Among non-Hispanic blacks, the D allele was significantly associated (P < 0.05) with increased SBP in additive and dominant covariate-adjusted models and was also associated with increased DBP in dominant models when participants taking ACE inhibitors were excluded from the analyses. No other significant associations were observed in any race/ethnic group. Significant genotype-sex interactions were detected among Mexican Americans, for whom positive associations with SBP and hypertension were seen among females, but not males.

CONCLUSIONS

This study gives limited support for association of the ACE I/D variant with blood pressure and for sex-specific effects among particular race/ethnic groups, though we cannot rule out the role of genetic or environmental interactions.

Top Three Pharmacogenomics and Personalized Medicine Applications at the Nexus of Renal Pathophysiology and Cardiovascular Medicine

Pharmacogenomics is a field with origins in the study of monogenic variations in drug metabolism in the 1950s. Perhaps because of these historical underpinnings, there has been an intensive investigation of 'hepatic pharmacogenes' such as CYP450s and liver drug metabolism using pharmacogenomics approaches over the past five decades. Surprisingly, kidney pathophysiology, attendant diseases and treatment outcomes have been vastly under-studied and under-theorized despite their central importance in maintenance of health, susceptibility to disease and rational personalized therapeutics. Indeed, chronic kidney disease (CKD) represents an increasing public health burden worldwide, both in developed and developing countries. Patients with CKD suffer from high cardiovascular morbidity and mortality, which is mainly attributable to cardiovascular events before reaching end-stage renal disease. In this paper, we focus our analyses on renal function before end-stage renal disease, as seen through the lens of pharmacogenomics and human genomic variation. We herein synthesize the recent evidence linking selected Very Important Pharmacogenes (VIP) to renal function, blood pressure and salt-sensitivity in humans, and ways in which these insights might inform rational personalized therapeutics. Notably, we highlight and present the rationale for three applications that we consider as important and actionable therapeutic and preventive focus areas in renal pharmacogenomics: 1) ACE inhibitors, as a confirmed application, 2) VDR agonists, as a promising application, and 3) moderate dietary salt intake, as a suggested novel application. Additionally, we emphasize the putative contributions of gene-environment interactions, discuss the implications of these findings to treat and prevent hypertension and CKD. Finally, we conclude with a strategic agenda and vision required to accelerate advances in this under-studied field of renal pharmacogenomics with vast significance for global public health.

Gene polymorphisms contributing to hypertension in immunoglobulin A nephropathy

BACKGROUND

Hypertension, which is affected by genetic and environmental factors, is one of the major risk factors for chronic kidney disease. Identification of the genetic factor contributing to hypertension in patients with chronic kidney disease may potentially refine a therapeutic strategy.

METHODS

In the present multicenter cross-sectional study, 240 patients were eligible (aged 15-50 years with urinary protein ≥0.25 g/day) out of 429 patients who were diagnosed as having immunoglobulin (Ig) A nephropathy (IgAN) by renal biopsy between 1990 and 2005 and enrolled in our previous study, PREDICT-IgAN. The outcome was hypertension defined as ≥140 and/or ≥90 mmHg of systolic and diastolic blood pressure and/or use of antihypertensives at renal biopsy. We assessed associations between hypertension and 28 polymorphisms with the frequency of minor genotype ≥10% among 100 atherosclerosis-related polymorphisms using the Chi-squared test in dominant and recessive models. We identified polymorphisms associated with hypertension in multivariate logistic regression models.

RESULTS

Baseline characteristics: hypertension 36.3%. Among 28 polymorphisms, the Chi-squared test revealed that CD14 (-159CC vs CT/TT, P = 0.03) and ACE (DD vs DI/II, P = 0.03) were significantly associated with hypertension after Bonferroni correction. Multivariate logistic regression models revealed that CD14 -159CC [vs CT/TT, odds ratio (OR) 3.58 (95% confidence interval (CI) 1.66-7.63)] and ACE DD [vs DI/II, OR 4.41 (95% CI 1.80-10.8), P = 0.001] were independently associated with hypertension.

CONCLUSIONS

CD14 C-159T and ACE I/D contributed to hypertension in patients with IgAN.

The ACE gene and human performance: 12 years on

Some 12 years ago, a polymorphism of the angiotensin I-converting enzyme (ACE) gene became the first genetic element shown to impact substantially on human physical performance. The renin-angiotensin system (RAS) exists not just as an endocrine regulator, but also within local tissue and cells, where it serves a variety of functions. Functional genetic polymorphic variants have been identified for most components of RAS, of which the best known and studied is a polymorphism of the ACE gene. The ACE insertion/deletion (I/D) polymorphism has been associated with improvements in performance and exercise duration in a variety of populations. The I allele has been consistently demonstrated to be associated with endurance-orientated events, notably, in triathlons. Meanwhile, the D allele is associated with strength- and power-orientated performance, and has been found in significant excess among elite swimmers. Exceptions to these associations do exist, and are discussed. In theory, associations with ACE genotype may be due to functional variants in nearby loci, and/or related genetic polymorphism such as the angiotensin receptor, growth hormone and bradykinin genes. Studies of growth hormone gene variants have not shown significant associations with performance in studies involving both triathletes and military recruits. The angiotensin type-1 receptor has two functional polymorphisms that have not been shown to be associated with performance, although studies of hypoxic ascent have yielded conflicting results. ACE genotype influences bradykinin levels, and a common gene variant in the bradykinin 2 receptor exists. The high kinin activity haplotye has been associated with increased endurance performance at an Olympic level, and similar results of metabolic efficiency have been demonstrated in triathletes. Whilst the ACE genotype is associated with overall performance ability, at a single organ level, the ACE genotype and related polymorphism have significant associations. In cardiac muscle, ACE genotype has associations with left ventricular mass changes in response to stimulus, in both the health and diseased states. The D allele is associated with an exaggerated response to training, and the I allele with the lowest cardiac growth response. In light of the I-allele association with endurance performance, it seems likely that other regulatory mechanisms exist. Similarly in skeletal muscle, the D allele is associated with greater strength gains in response to training, in both healthy individuals and chronic disease states. As in overall performance, those genetic polymorphisms related to the ACE genotype, such as the bradykinin 2 gene, also influence skeletal muscle strength. Finally, the ACE genotype may influence metabolic efficiency, and elite mountaineers have demonstrated an excess of I alleles and I/I genotype frequency in comparison to controls. Interestingly, this was not seen in amateur climbers. Corroboratory evidence exists among high-altitude settlements in both South America and India, where the I allele exists in greater frequency in those who migrated from the lowlands. Unfortunately, if the ACE genotype does influence metabolic efficiency, associations with peak maximal oxygen consumption have yet to be rigorously demonstrated. The ACE genotype is an important but single factor in the determinant of sporting phenotype. Much of the mechanisms underlying this remain unexplored despite 12 years of research.

Rat Ace allele variation determines susceptibility to AngII-induced renal damage

INTRODUCTION

Ace b/l polymorphism in rats is associated with differential tissue angiotensin-converting enzyme (ACE) expression and activity, and susceptibility to renal damage. Same polymorphism was recently found in outbred Wistar rat strain with b allele accounting for higher renal ACE, and provided a model for studying renin-angiotensin-aldosterone system (RAAS) response behind the innate high or low ACE conditions.

METHODS

We investigated the reaction of these alleles on chronic angiotensin II (AngII) infusion. Wistar rats were selected to breed male homozygotes for the b (WU-B) or l allele (WU-L) (n = 12). For each allele, one group (n = 6) received AngII infusion via an osmotic minipump (435 ng/kg/min) for 3 weeks. The other group (n = 6) served as a control.

RESULTS

WU-B had higher ACE activity at baseline then WU-L. Interestingly, baseline renal ACE2 expression and activity were higher in WU-L. AngII infusion induced the same increase in blood pressure in both genotypes, no proteinuria, but caused tubulo-interstitial renal damage with increased α-SMA and monocyte/macrophage influx only in WU-B (p < 0.05). Low ACE WU-L rats did not develop renal damage.

CONCLUSION

AngII infusion causes proteinuria-independent renal damage only in rats with genetically predetermined high ACE while rats with low ACE seemed to be protected against the detrimental effect of AngII. Differences in renal ACE2, mirroring those in ACE, might be involved.

Rat Ace allele variation determines susceptibility to AngII-induced renal damage

INTRODUCTION

Ace b/l polymorphism in rats is associated with differential tissue angiotensin-converting enzyme (ACE) expression and activity, and susceptibility to renal damage. Same polymorphism was recently found in outbred Wistar rat strain with b allele accounting for higher renal ACE, and provided a model for studying renin-angiotensin-aldosterone system (RAAS) response behind the innate high or low ACE conditions.

METHODS

We investigated the reaction of these alleles on chronic angiotensin II (AngII) infusion. Wistar rats were selected to breed male homozygotes for the b (WU-B) or l allele (WU-L) (n = 12). For each allele, one group (n = 6) received AngII infusion via an osmotic minipump (435 ng/kg/min) for 3 weeks. The other group (n = 6) served as a control.

RESULTS

WU-B had higher ACE activity at baseline then WU-L. Interestingly, baseline renal ACE2 expression and activity were higher in WU-L. AngII infusion induced the same increase in blood pressure in both genotypes, no proteinuria, but caused tubulo-interstitial renal damage with increased α-SMA and monocyte/macrophage influx only in WU-B (p < 0.05). Low ACE WU-L rats did not develop renal damage.

CONCLUSION

AngII infusion causes proteinuria-independent renal damage only in rats with genetically predetermined high ACE while rats with low ACE seemed to be protected against the detrimental effect of AngII. Differences in renal ACE2, mirroring those in ACE, might be involved.

Response to angiotensin-converting enzyme inhibition is selectively blunted by high sodium in angiotensin-converting enzyme DD genotype: evidence for gene-environment interaction in healthy volunteers

BACKGROUND

Renin-angiotensin-aldosterone system blockade is a cornerstone in cardiovascular protection. Angiotensin-converting enzyme (ACE)-DD genotype has been associated with resistance to angiotensin-converting enzyme inhibition (ACEi), but data are conflicting. As sodium intake modifies the effect of ACEi as well as the genotype-phenotype relationship, we hypothesize gene-environment interaction between sodium-status, the response to ACEi, and ACE genotype.

METHOD

Thirty-five male volunteers (26 ± 9 years; II n = 6, ID n = 18, DD n = 11) were studied during placebo and ACEi (double blind, enalapril 20 mg/day) on low [7 days 50 mmol Na/day (low salt)] and high [7 days 200 mmol Na/day (high salt)] sodium, with a washout of 6 weeks in-between. After each period mean arterial pressure (MAP) was measured before and during graded infusion of angiotensin II (Ang II).

RESULTS

During high salt, ACEi reduced MAP in II and ID, but not in DD [II: 88 (78-94) versus 76 (72-88); ID: 87 (84-91) versus 83 (79-87); both P < 0.05 and DD: 86 (82-96) versus 88 (80-90); ns, P < 0.05 between genotypes]. However, during low salt, ACEi reduced MAP in all genotype groups [II: 83 (78-89) versus 77 (72-83); ID: 88 (84-91) versus 82 (78-86); DD: 84 (80-91) versus 81 (75-85); all P < 0.05]. During high salt + ACEi, the Ang II response was blunted in DD, with an 18% rise in MAP during the highest dose versus 22 and 31% in ID and II (P < 0.05). Low salt annihilated these differences.

CONCLUSION

In healthy participants, the MAP response to ACEi is selectively blunted in DD genotype during high salt, accompanied by blunted sensitivity to Ang II. Low salt corrects both abnormalities. Further analysis of this gene-environment interaction in patients may contribute to strategies for improvement of individual treatment efficacy.