The renin-angiotensin system genetic polymorphisms and rheumatic mitral valve disease

BACKGROUND AND AIM OF THE STUDY: Angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism, angiotensinogen (AGT) gene polymorphism and angiotensin II type 1 receptor (AT1R) polymorphism in relation to rheumatic mitral valve disease were examined in a case-control study to investigate possible relationships between these gene polymorphisms and rheumatic mitral valve disease in patients undergoing mitral valve replacement (MVR). METHODS: A total of 50 patients with rheumatic mitral valve disease and undergoing MVR was compared with 50 normal, and age- and sex-matched control subjects. ACE I/D, AGT gene M235T and AT1R-adenine/cytosine 1166 (A1166C) genotype polymorphisms were identified by polymerase chain reaction (PCR) -based restriction analysis. RESULTS: ACE I/D polymorphism differed significantly between the groups. The control group mostly represented the heterozygote ID allele (74%), while the MVR group showed frequencies of 60% for the homozygote DD and II alleles. MM homozygote frequency was significantly greater in controls, but TT homozygote frequency was significantly greater in the MVR group. AT1R-A1166C genotype polymorphism also differed significantly between groups; the MVR group had 73.7% of the AC heterozygote allele, while controls had 64.4% of the AA and 66.7% of the CC homozygote alleles. CONCLUSION: These results provided evidence of an association between ACE I/D polymorphism, M235T polymorphism and AT1R-A1166C genotype polymorphism and rheumatic mitral valve disease.     

The DD genotype of the angiotensin converting enzyme gene is negatively associated with right ventricular hypertrophy in male patients with chronic obstructive pulmonary disease.

The renin angiotensin system plays an important role in the development of pulmonary artery remodeling and right ventricular hypertrophy in hypoxia-induced pulmonary hypertension as may occur in patients with COPD. Several polymorphisms of genes encoding for components of the renin angiotensin system such as the M235T polymorphism in the angiotensinogen gene, the 287-base-pair insertion (I)/deletion (D) polymorphism at intron 16 of the ACE gene, and the A1166C polymorphism in the angiotensin II type 1 receptor gene have been associated with an increased risk of cardiovascular diseases. With respect to the pulmonary circulation, only limited data exist on possible associations between polymorphisms of these genes and pulmonary hypertension and/or right ventricular hypertrophy. The objective of the present study was to investigate a possible relationship between polymorphisms of the renin angiotensin system and electrocardiographic evidence of right ventricular hypertrophy in patients with COPD. We therefore determined the angiotensinogen (M235T), angiotensin converting enzyme (I/D), and angiotensin II type 1 receptor (A1166C) genotypes in 87 patients with severe COPD and correlated these data with electrocardiographic parameters of right ventricular hypertrophy. Thirty-one patients (36%) of 87 patients with COPD showed electrocardiographic evidence of right ventricular hypertrophy. In the male, but not in the female, subgroup, the angiotensin-converting enzyme DD genotype was negatively associated with electrocardiographic evidence of right ventricular hypertrophy (male: chi2 = 3.8, p = 0.05; female: chi2 = 0.05, p = 0.82). We found no associations between the investigated polymorphisms in the angiotensinogen and angiotensin II type 1 receptor genes and electrocardiographic evidence of right ventricular hypertrophy.     

The M235T polymorphism in the angiotensinogen gene is associated with the risk of malignant hypertension in white patients

BACKGROUND: Malignant hypertension can be considered an extreme phenotype of renin-mediated hypertension. Therefore, we compared the allelic frequencies of the angiotensinogen (AGT) M235T, angiotensin-converting enzyme insertion/deletion (ACE I/D) and angiotensin II-type I receptor (AT1R) A1166C polymorphisms in malignant hypertensive patients with hypertensive and normotensive controls. METHODS: A total of 101 consecutive patients between 1995 and 2005 admitted to a large university hospital fulfilled the criteria for malignant hypertension. Seventy-five patients (74%) were compared with 150 hypertensive and 150 normotensive controls, randomly selected from a population study and individually matched on age, sex and ethnicity. RESULTS: The odds of malignant hypertension in white subjects with the TT genotype of the AGT M235T polymorphism was 14.3 (5.5-37) compared to hypertensive controls, and 9.4 (3.8-23.2) compared to normotensive controls. Adjustment for age, sex, smoking and antihypertensive therapy did not affect this association. The association of AGT M235T with malignant hypertension was not significant in blacks. In patients with malignant hypertension, the TT genotype was associated with more severe renal dysfunction and microangiopathic haemolysis. No differences were found in allele frequencies of the ACE I/D or the AT1R A1166C polymorphisms between study groups. CONCLUSIONS: The TT genotype of AGT M235T is associated with malignant hypertension in whites, carriers having an odds of approximately 10 to 1 compared to hypertensive and normotensive controls. These observations may provide a better understanding of the pathophysiology of malignant hypertension and offer possibilities for identifying patients at risk. Larger association or linkage studies are needed for a more detailed risk assessment.     

A/C1166 gene polymorphism of the angiotensin II type 1 receptor (AT1) and ambulatory blood pressure: the Ohasama Study.

We previously investigated the relation between hypertension and each of three major genetic polymorphisms in the renin-angiotensin (AGT)-aldosterone system (R-A-A), AGT M235T, angiotensin convert enzyme (ACE) I/D, and CYP11B2 -344C/T, by means of ambulatory blood pressure (ABP) monitoring in a general Japanese population (the Ohasama Study). A/C1166 gene polymorphism in the 3' untranslated region of the angiotensin II type 1 receptor (AT1) gene is the final remaining major target in R-A-A to be examined in the Ohasama Study population. In the present study, the AT1 A/C1166 polymorphism was genotyped by the TaqMan polymerase chain reaction (PCR) method or restriction fragment length polymorphism (RFLP) in 802 Japanese subjects aged 40 and over, who were previously genotyped for the AGT M235T, ACE D/I, CYP11B2 -344C/T polymorphisms. The AA genotype, AC genotype, and CC genotype were present in 678 (84.5%), 121 (15.1%), and 3 (0.4%) of subjects, respectively. Since the frequency of the C allele was quite low (0.079), the genotypes were classified according to the presence or absence of the C allele. Although daytime blood pressure (BP) was higher in subjects with the C allele, the difference was not statistically significant after adjusting for age, gender, body mass index, and smoking status. No significant difference was noted in the prevalence of cardiovascular diseases or nocturnal BP decline between the two groups. These results indicated that AT1 A/C1166 polymorphism was not associated with any clinical parameters associated with hypertension or atherosclerosis in the Japanese population.     

肾素-血管紧张素系统双基因多态性与高血压合并舒张性心力衰竭的关系

目的探讨中国南方部分汉族高血压患者肾素一血管紧张素系统中血管紧张素转换酶（ACE）及血管紧张素原（AGT）双基因多态性与舒张性心力衰竭发病的关系。方法应用聚合酶链反应及限制性片断长度多态性技术,对432例高血压患者的ACE基因插入／缺失（I／D）及AGTM235T多态性进行检测。将其中207例合并舒张性心力衰竭者作为病例组,其余225例心功能正常者作为对照组。结果①病例组DD基因型及D等位基因的频率均高于对照组;②病例组TT基因型及T等位基因的频率与对照组比较差异无统计学意义;③联合分析ACE与ACT基因多态性显示,两组中同时具有DD型ACE基因及TT型AGT基因的频率分别为29．0％及14．9％,前者明显高于后者。结论DD型ACE基因可能是该地区高血压患者舒张性心力衰竭发病的遗传危险因素,ACE和AGT基因在慢性心力衰竭的发生中具有协同作用。     

Population-based case-control study of renin-angiotensin system genes polymorphisms and hypertension among Hispanics.

The effect of polymorphisms of the RAS genes on the incidence of hypertension seems to be population-dependent. We studied the effects of the angiotensinogen T174M and M235T, angiotensin converting enzyme insertion/deletion (ACE I/D), and angiotensin II receptor 1 (AT1R) A1166C gene polymorphisms on the risk of hypertension among Hispanics. We selected all cases (n=256) and 257 age and sex group-matched controls from a random sample of free living Colombians (n=2,989). Logistic regression was used to estimate the independent effect of each polymorphism. All polymorphisms were in Hardy-Weinberg equilibrium in controls, with the exception of M235T, which showed a small excess of heterozygotes (p=0.005; disequilibrium coefficient, D=-0.0264). After adjustment for age, sex, body mass index, race, physical activity, family history of hypertension and cardiovascular disease, and other polymorphisms, subjects with the ACE DD genotype were 1.56 times (95% confidence interval [CI]: 1.05, 2.33) more likely to be hypertensive than carriers of the I allele (p=0.03). Also, adjusted systolic and diastolic blood pressure were 4.58 (95% CI: -0.39, 9.56) and 3.32 (95% CI: 0.78, 5.86) mmHg higher in DD homozygous individuals than in carriers of the I allele, respectively. Approximately 15% of the cases of hypertension in this population could be attributed to carriage of the DD genotype. None of the other polymorphisms was associated with either hypertension or blood pressure level. In conclusion, the ACE DD genotype appears to be an independent risk factor for development of hypertension and may explain a significant fraction of incident cases among Hispanics.     

Relationship between polymorphisms in the renin-angiotensin system and nephropathy in type 2 diabetic patients

BACKGROUND: Renin Angiotensin system is involved in renal function and its polymorphisms may influence diabetic nephropathy. ID ACE polymorphism modulates ACE level whereas M235T AGT polymorphism is involved in arterial hypertension. The A1166C AT1R polymorphism is involved in arterial hypertension and in diabetic retinopathy.METHODS: Two hundred thirty five type 2 diabetic patients were enrolled in this transversal study. Data were documented for clinical characteristics of the population, HbA(1c), urinary albumin excretion, presence of retinopathy or antihypertensive treatment. Polymorphisms were analyzed by PCR techniques. The patients were divided into 3 groups: group 1, without nephropathy (n=118), group 2, microalbuminuria (n=78), group 3, macroalbuminuria (n=39).RESULTS: Diabetes duration was longer (p<0.001), retinopathy (p<0.001) and antihypertensive treatment (p<0.02) were more frequent in group 3 compared to group 1 and 2. The I/D ACE and M235T AGT polymorphisms were not differently distributed between the three groups. In contrast, the CC genotype of the AT1R polymorphism was overrepresented in group 2 (p=0.021). The presence of the CC AT1R genotype considerably increased the incidence of albuminuria after 10 years of diabetes (AA vs CC p=0.01), particurlarly in men. No effect was seen with I/D ACE and M235T AGT polymorphisms.CONCLUSION: In conclusion, we observed an interaction of A1166C AT1R polymorphism with diabetes in men but not of I/D ACE and M235T AGT polymorphisms.     

Angiotensinogen gene M235T polymorphism predicts left ventricular hypertrophy in endurance athletes.

OBJECTIVES: We studied whether left ventricular mass in athletes associates with polymorphisms in genes encoding components of the renin-angiotensin system. BACKGROUND: Adaptive left ventricular hypertrophy is a feature of the athlete's heart. However, similarly training athletes develop left ventricular mass to a different extent, suggesting that genetic factors may modulate heart size. METHODS: We measured left ventricular mass by echocardiography in 50 male and 30 female elite endurance athletes aged 25 +/- 4 (mean +/- SD) years. Deoxyribonucleic acid samples were prepared for genotyping of angiotensinogen (AGT) gene M235T polymorphism, angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and angiotensin II type 1 receptor (AT1) gene A1166C polymorphism. RESULTS: The AGT gene M235T genotypes were significantly associated with left ventricular mass independently of blood pressure in both genders (p = 0.0036 for pooled data). TT homozygotes had greater mass compared with MM homozygotes in both men (147 +/- 12 g/m vs. 132 +/- 15 g/m, p = 0.032) and women (121 +/- 12 g/m vs. 101 +/- 13 g/m, p = 0.019). There was a gender difference in the relation between myocardial mass and AGT genotype, MT heterozygotes resembling MM homozygotes among women and TT homozygotes among men. The other studied gene polymorphisms were not associated with left ventricular mass. CONCLUSIONS: Angiotensinogen gene M235T polymorphism is associated with the variability in left ventricular hypertrophy induced by endurance training, with athletes homozygous for the T allele having the largest hearts. We found no association between ACE gene I/D or AT1 gene A1166C polymorphisms and left ventricular mass.     

Renin-angiotensin system genes in chronic glomerulonephritis

Glomerulonephritis is a group of diseases with complex etiology, pathogenesis, morphological features and clinical course. The renin-angiotensin system genes are important group of candidate genes involved in pathogenesis of chronic renal diseases. The purpose of our study was to analyze the association of genetic polymorphisms of these genes with glomerular kidney diseases. The study population consisted of 52 patients with immunological glomerular kidney diseases and 50 hemodialyzed patients with end-stage renal failure with glomerulonephritis as primary disease. The control group consisted of 200 healthy subjects. By means of the polymerase chain reaction (PCR) the following polymorphisms were evaluated: insertion/deletion (I/D) polymorphism in intron 16 of the angiotensin-converting enzyme gene (ACE), M235T polymorphism of the angiotensinogen gene (AGT) and A1166C polymorphism of the angiotensin II type 1 receptor gene (AT1R). No significant association was found between the ACE allele and genotype frequencies and the disease. The allele frequency of the M235T polymorphism was different from that observed in the control group, but differences in the genotype distribution were not statistically significant. The CC genotype of the AT1R gene polymorphism was significantly more frequent in patients than controls. This suggests an increased susceptibility to renal diseases in individuals carrying the CC genotype. This relationship is not associated with hypertension. Our results suggest that in the Polish population the AT1R gene polymorphism might be associated with increased susceptibility to chronic renal diseases.     

Genetic polymorphisms of the renin-angiotensin system and atheromatous renal artery stenosis

Genes that influence the renin-angiotensin system have been investigated in recent years as potential etiologic candidates of cardiovascular and renal diseases. In atheromatous renal artery stenosis (RAS), a condition characterized by persistent activation of the renin-angiotensin system, the study of these genes may be of particular relevance. We evaluated angiotensin-converting enzyme (ACE) insertion/deletion, angiotensinogen (AGT) M235T, and angiotensin II receptor (ATR) A1166C polymorphisms in relation to the occurrence of RAS. We studied 58 patients with angiographically documented RAS; 102 normotensive subjects with normal coronary arteries and no history or clinical or instrumental evidence of atherosclerosis in other vascular districts were considered the control group. Patients had a significantly higher D allele frequency (0.70 versus 0.55; chi(2) 6.88, P=0.01; odds ratio [OR] 1. 9, 95% CI 1.17 to 3.07) than did the control population; 48.3% of patients were homozygous for DD (chi(2) 6.62, P<0.05; OR 2.04, 95% CI 1.05 to 3.95); and only 8.6% carried the II genotype (OR 0.34, 95% CI 0.19 to 1.47). No significant association was found for AGT M235T and ATR A1166C. Our results suggest a predisposing role for ACE genetic polymorphism in the development and progression of atheromatous RAS.     

Genotype-phenotype relationships for the renin-angiotensin-aldosterone system in a normal population.

The renin-angiotensin-aldosterone system plays an important role in blood pressure regulation by influencing salt-water homeostasis and vascular tone. The purpose of the present study was to search for associations of single nucleotide polymorphisms on 3 major candidate genes of this system with the plasma concentrations of the corresponding renin-angiotensin-aldosterone system components considered as quantitative phenotypes. Genotyping was performed in 114 normotensive subjects for different variants of the angiotensinogen (AGT) gene (C-532T, G-6A, M235T), the angiotensin I-converting enzyme (ACE) gene [4656(CT)(2/3)], the aldosterone synthase (CYP11B2), and the type 1 angiotensin II receptor (AT1R) gene (A1166C) by hybridization with allele-specific oligonucleotides (ASO) or enzymatic digestion of polymerase chain reaction products. Plasma levels of AGT, ACE, angiotensin II (Ang II), aldosterone, and immunoreactive active renin were measured according to standard techniques. Platelet binding sites for Ang II were analyzed by the binding of radioiodinated Ang II to purified platelets. B(max) and K(D) values of the Ang II binding sites on platelets of each individual were calculated to examine a possible relationship between these parameters and the AT1R genotype. A highly significant association of the ACE 4656(CT)(2/3) variant with plasma ACE levels was observed (P<0.0001). ANOVA showed a significant effect of the AGT C-532T polymorphism on AGT plasma levels (P=0.017), but no significant effect was detectable with the other AGT polymorphisms tested, such as the G-6A or the M235T. A significant effect association was also found between the C-344T polymorphism of the CYP11B2 gene and plasma aldosterone levels, with the T allele associated with higher levels (P=0.02). No genotype effect of the AT1R A1166C polymorphism was detected either on the B(max) or the K(D) value of the Ang II receptors on platelets.     

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.     

血管紧张素转换酶和血管紧张素受体基因多态性与冠心病的关系

目的　探讨深圳地区冠心病 (CAD)与血管紧张素转换酶 (ACE)基因与血管紧张素 的 1型受体 (AT1R)基因多态性的关系。方法　分别采用 PCR及 PCR- Afl II酶切法 ,检测 89例 CAD患者和 14 8例健康对照的 ACE和AT1R基因型。结果　 CAD组与对照组比较 ,ACE DD基因型频率 (2 4 .7%比 8.1% ,P<0 .0 1)及 D型等位基因频率 (4 4 .4 %比 33.4 % ,P<0 .0 5 )均为升高。 CAD组与对照组 AT1R基因型频率分布无显著性差异 (P>0 .0 5 )。携带 AT1R C等位基因的个体患 CAD的风险与其同时携带 ACE DD基因型无关 (P>0 .0 5 )。结论　深圳地区CAD的发生和发展可能与 ACE基因 I/ D多态性有关 ,而与 AT1R基因 A116 6 C多态性无关     

Hypertension-related gene polymorphisms in pre-eclampsia, eclampsia and gestational hypertension in Black South African women

OBJECTIVE: To examine whether polymorphisms in the renin-angiotensin system (RAS) are associated with pregnancy-related hypertensive disorders in a black South African population. DESIGN: The angiotensin-converting enzyme (ACE) insertion/deletion, angiotensinogen M235T and angiotensin II receptor type 1 1166A<--C polymorphisms were assessed in study groups comprising 204 women with pre-eclampsia, 120 with eclampsia, 67 with early onset pre-eclampsia and 78 with gestational hypertension. METHODS: Using chi analysis, results were compared with those obtained from 338 ethnically matched normotensive pregnant women following normal full term pregnancies. No significant differences in the distribution of any of these polymorphisms were found between patients with pre-eclampsia or eclampsia and the normal control subjects. Patients with gestational hypertension were less frequently homozygous for the ACE insertion polymorphism compared with controls (5 versus 13%, respectively; P = 0.049; odds ratio 0.36 [95% confidence interval (CI) 0.09-1.04]). CONCLUSION: The commonly occurring RAS polymorphisms are not predictive of pre-eclampsia or eclampsia in the Black South African population.     

Association between ACE and AGT polymorphism and cardiovascular risk in acromegalic patients

Purpose

Whether the renin–angiotensin–aldosterone system plays a role or not in the development of cardiovascular morbidity in acromegaly patients is unknown. The aim of the study was to investigate the association between ACE (I/D) and AGT (M235T) gene polymorphisms and cardiovascular and metabolic disorders in the acromegaly.

Methods

The study included one hundred and seventeen acromegalic patients (62 F/55 M, age: 50.2?±?12.3 years) and 106 healthy controls (92 F/14 M, age: 41.4?±?11.3 years). PCR method was used to evaluate the prevalence of ACE and AGT genotype.

Results

The genotypes of ACE polymorphism in acromegalic patients were distributed as follows; 41.0% (n: 48) for DD, 44.4% (n: 52) for ID and 14.5% (n: 17) for II genotype. The control group had significantly different distribution of the ACE polymorphism [48.1% (n: 51) for DD, 25.5% (n: 27) for ID and 26.4% (n: 28) for II genotype]compared to acromegalic group. Regarding AGT polymorphism, AGT-MT genotype was seen in 88.9% of the acromegalic patients while MM and TT genotype (9.4% and 1.7%, respectively) were present in the rest. The controls had similar distribution of the AGT genotype with the acromegaly group (80.2% MT genotype, 15.1% MM genotype and 4.7% TT genotype). Due to the small number of patients with TT allele (n: 2), T carriers for AGT genotype (AGT-MT+TT) were subgrouped and compared to those with AGT-MM group. ACE-DD, ID and II groups had similar anthropometric measures, blood pressure values and baseline GH and IGF-1 levels. Significantly higher baseline GH levels were found in AGT-MM group compared to T allele carriers [40 (16–60) vs. 12 (5–36) µg/L, p?<?0.05]. The compared groups in both polymorphisms had similar fasting plasma glucose levels. Patients with ACE-II genotype had significantly higher HDL-C levels compared to those with ACE-DD and ACE-ID polymorphisms (p?<?0.05) whereas there was no significant difference in lipid profile between AGT-MM group and AGT-T allele carriers. Moreover, the compared groups in both polymorphisms had similar distribution of hyperlipidemia, hypertension, impaired glucose metabolism (prediabetes or type 2 diabetes mellitus) and coronary artery disease. In terms of echocardiographic parameters, systolic and diastolic function was similar among the groups in ACE and AGT genotypes. Interestingly, AGT-MM group had higher mitral inflow A_peak values than T allele carriers (0.94?±?0.46 vs. 0.73?±?0.20; p?=?0.051). No significant difference was observed in LV mass index values in acromegalic patients among the groups in both polymorphisms.

Conclusions

Both ACE (I/D) and AGT (M235T) gene polymorphisms do not seem to have a significant effect on the development of clinical properties or cardiovascular comordities of acromegalic patients.

     

Renin-angiotensin system gene polymorphisms: assessment of the risk of coronary heart disease

BACKGROUND: Renin-angiotensin system genes are candidate genes in cardiovascular system diseases. Angiotensinconverting enzyme (ACE), angiotensinogen (AGT) and angiotensin II type 1 receptor (AT1R) gene polymorphisms are considered risk factors in coronary heart disease (CHD). AIM: To evaluate the involvement of the ACE, AGT and AT1R genetic variants in predisposition to CHD as well as their association with other known risk factors. METHODS: The study included 400 male subjects (200 with CHD and 200 healthy individuals). Genotypes were determined by a polymerase chain reaction (PCR). For the AGT and AT1R genes a restriction analysis of the PCR product was performed. The allele frequency and genotype distribution were compared between groups. RESULTS: The allele and genotype frequencies of the ACE gene were similar in both groups, however, a significantly higher frequency of the DD genotype was observed in the presence of hyperlipidemia (39% vs 24% in non-hyperlipidemic subjects, p<0.01). The AGT gene polymorphism was associated with the development of CHD. The T allele was significantly more frequent in patients than in the control group (55% vs 44%, p<0.05). The heterozygous MT genotype was observed in 61% of patients compared to 40% in the controls (p<0.05). The A1166C polymorphism of the AT1R gene was also associated with CHD as well as with age at the onset of disease. The frequency of the C allele was 29% compared to 21% in the control group (p<0.01) and the frequency of the CC homozygote was almost three times higher in patients. CONCLUSIONS: There is an association between molecular variants of the angiotensinogen and angiotensin II type 1 receptor and increased risk of CHD. The DD genotype of the ACE gene polymorphism and the TT genotype of the AGT gene polymorphism were significantly more frequent in patients with hyperlipidemia. The TT genotype of the AGT gene M235T polymorphism was associated with an increased risk of CHD and myocardial infarction only in smokers.     

Renin Angiotensin System Gene Polymorphisms Modify Angiotensin‐Converting Enzyme Inhibitors' Effect on Cognitive Function: The Health,Aging and Body Composition Study

OBJECTIVES: To investigate the effect of polymorphisms in renin angiotensin system genes on the association between angiotensin‐converting enzyme inhibitor (ACEI) exposure and global and executive cognitive function in the Health, Aging and Body Composition study. DESIGN: Cohort study. SETTING: Community. PARTICIPANTS: Three thousand seventy‐five participants: mean age 73.6, 58% Caucasian, 52% female, 15% taking ACE‐Is, 8 years of follow‐up. MEASUREMENTS: The outcomes were longitudinal change in Executive Clock Drawing Test‐1 (CLOX1), the Digit Symbol Substitution test, and the Modified Mini‐Mental State Examination. The genetic polymorphisms included angiotensin‐converting enzyme insertion deletion (ACEID) in the ACE gene and the M235T and 6AG polymorphisms in the angiotensinogen (AGT) gene. RESULTS: For the CLOX1 outcome, there was significant interaction between 6AG and M235T polymorphisms in the AGT gene and angiotensin‐converting enzyme inhibitors (ACE‐Is) in Caucasian participants (P=.01 for both polymorphisms) independent of blood pressure levels. Specifically, ACE‐I exposure was protective against CLOX1 score decline in carriers of the AA genotype of the 6AG and the CC genotype of the M235T (for the ACE‐I vs non‐ACE‐I groups, P=.01 for 6AG and P=.005 for M235T) but not the other genotypes. These associations were not significant with other cognitive tests, with ACEID, or in African Americans. CONCLUSION: ACE‐Is may provide a protective effect on executive function in Caucasians with AGT gene polymorphisms known to be associated with greater renin angiotensin system activity. If confirmed in a pharmacogenetic trial, ACE‐Is may be found to have additional cognitive protection in a select group of elderly individuals.     

Association of the renin-angiotensin system gene polymorphism with nephropathy in type II diabetes

Diabetic nephropathy is the most frequent cause of end-stage renal failure. One of the crucial factors in a development of renal and cardiovascular complications of diabetes is genetic predisposition. The genes of the renin-angiotensin system are important group of candidate genes involved in pathogenesis of chronic renal diseases. The purpose of our study was the evaluation of a possible role of genetic polymorphisms of some of the RAS system genes in the nephropathy in type 2 diabetes. The study was performed in 117 patients with diabetic nephropathy, compared with 200 healthy subjects as a control group. The following polymorphisms: insertion/deletion (I/D) of the angiotensin-converting enzyme gene (ACE), M235T of the angiotensinogen gene (AGT) and A1166C of the angiotensin II type 1 receptor gene (AT1R) were evaluated by polymerase chain reaction (PCR). No statistically significant differences between groups were found in the allele frequency and genotype distribution for ACE and AGT polymorphisms. The results for the AT1R gene polymorphism revealed significant differences in allele and genotype frequencies. The homozygous CC genotype was more frequent in patients with diabetic nephropathy than in control group. Both genotypes with the C allele (AC + CC) were found in 56% of patients compared to 38% in control group. These results suggest increased susceptibility to diabetic nephropathy in individuals carrying the CC genotype. Therefore, the A1166C polymorphism of the AT1R gene could be a potential genetic marker for increased susceptibility to renal complications in type 2 diabetes.     

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 M(235)T) and angiotensin II type 1 receptor (AGTR1 A(1166)C) 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 ofDD 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; chi2 = 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.     

Genetic variation in the renin-angiotensin system modifies the beneficial effects of ACE inhibitors on the risk of diabetes mellitus among hypertensives

The aim of this study was to assess whether the association between angiotensin-converting enzyme (ACE) inhibitor use and the incidence of treated diabetes mellitus is modified by genetic polymorphisms in the renin-angiotensin system (RAS).In a nested case-control study, treated hypertensive patients were genotyped for ACE (insertion (I)/deletion (D)), angiotensinogen (AGT; M235T) and angiotensin II type 1 receptor (AGTR1; A1166C). Cases of newly treated diabetes were identified based on pharmacy records and controls were not yet drug treated for diabetes (case:control ratio 1:10). Self-administered questionnaires and physical examinations were used to assess risk factors for diabetes mellitus. Logistic regression was used to calculate the relative risk of diabetes associated with ACE inhibitor use relative to other antihypertensive treatment, stratified by the RAS genotypes. Among 205 cases and 2050 controls, homozygous 1166A carriers of the AGTR1 gene had a significantly decreased incidence of diabetes associated with current use of ACE inhibitors (odds ratio, OR: 0.47; 95% CI: 0.26-0.84), whereas this incidence was increased among 1166C allele carriers (OR: 1.32; 95% CI: 0.81-2.14). The interaction OR was 3.21 (95% CI: 1.53-6.75). ACE I allele carriers had a significantly reduced incidence of diabetes associated with ACE inhibitors use (OR: 0.63; 95% CI: 0.41-0.98), whereas DD homozygotes had no reduced risk (OR: 0.95; 95% CI: 0.46-1.96). The risk of diabetes associated with ACE inhibitor use was not significantly modified by the AGT-M235T polymorphism. Treatment with ACE inhibitors in hypertensive subjects significantly reduces the occurrence of diabetes in homozygous 1166A carriers of the AGTR1 gene and carriers of the ACE I allele, but not in 1166C allele carriers of the AGTR1 gene and in homozygous ACE D allele carriers.