Angiotensin II Type 1 Receptor A1166C Research Articles

The Role of Angiotensin II Type 1 Receptor A1166C Polymorphism in Autosomal Dominant Polycystic Kidney Disease.

Introduction Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic disorder that affects the kidney, which affects all ethnical groups worldwide, with varied clinical presentations and severity. The studies done in various parts of the world on the association between angiotensin II type 1 receptor (AT1R) A1166C gene polymorphism and ADPKD patientshave revealed inconsistent results. This study was done to assess the role of AT1R A1166C gene polymorphism in ADPKDin the South Indian population, which is the first of its kind. Methodology This is a case-control study, conducted at a tertiary care centerin South India. This study was concerned with the frequency of exposure (genotype) in ADPKD patients. Peripheral blood samples from 85 unrelated ADPKD patients and 94 controls without diabetes, hypertension, or any kidney-related disease were collected. The AT1R A1166C polymorphism was compared between (i) the cases and controls, (ii) early and late stages of chronic kidney disease(CKD) (ADPKD) subjects, and (iii) ADPKD subjects with and without hypertension. Results Among the ADPKD patients, 45 (52.9%) subjects showed early stage (CKD stages 1-3), and 40 (47%) subjects showed late stage CKD (CKD stages 4 and 5). The genotype distribution of the studied 85 ADPKD patients was almost similar. No significant association was found between the genotype distribution of AT1R A1166C polymorphism in AA vs. AC (OR = 1.11; 95% CI = 0.37-3.32; p < 0.844) and A vs. C (OR = 1.11; 95% CI = 0.38-3.32; p < 0.847) between cases and controls. The genotype distributions in genetic model AA vs. AC (OR = 3.07; 95% CI = 0.56-16.8; p < 0.177) and allelic model A vs. C (OR = 2.13; 95% CI = 0.40-11.3; p < 0.364) between the early and late CKD stages of ADPKD were also not significant. No significant association of gene polymorphism was found between the non-hypertensive and hypertensive groups of ADPKD. Conclusion The results of our study suggest there is no significant association between AT1R A1166C polymorphisms and ADPKD in the South Indian population. Further, the gene polymorphism is not related to the progression of ADPKD or the presence of hypertension in ADPKD cases in South India.

Association of polymorphism genes LPL , ADRB2 , AGT and AGTR1 with risk of hyperinsulinism and insulin resistance in the Kazakh population.

Hyperinsulinism and insulin resistance are closely associated with several common diseases including type 2 of diabetes, cardiovascular diseases, and metabolic syndrome. The present study aimed to determine the association between hyperinsulinism, insulin resistance and the polymorphism of genes, including angiotensin II receptor type 1 (AGTR1), angiotensinogen (AGT), β2-adrenoreceptor (ADRB2) and lipoprotein lipase (LPL), in the Kazakh population. The design of the current research was a case-control study, involving 460 subjects (age range, 18-65 years). For every subject, plasma glucose, insulin, total cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, apolipoprotein B and apolipoprotein A1 were examined. Moreover, reverse transcription-quantitative PCR was conducted to detect the polymorphism genes LPL Ser447Ter, ADRB2 Gln27Glu, AGT Thr174Met and AGTR1 A1166C. Hyperinsulinism was considered when the insulin level was elevated >24.9 IU/ml. The homeostasis model assessment insulin resistance (HOMA-IR) was used to evaluate insulin resistance. The subjects were divided into hyperinsulinism (17 men and 24 women) and normal level insulin (214 men and 205 women) groups, which were also split into insulin resistance group (HOMA-IR >2.7; 80 men and 105 women) and those without insulin resistance group (151 men and 124 women). The results suggested that LPL Ser447Ter (rs328) allele G was associated with a lower risk of hyperinsulinism (P=0.037). Furthermore, polymorphisms of genes ADRB2 Gln27Glu (rs1042714), AGT Thr174Met (rs4762) and AGTR1 A1166C (rs5186) were not associated with hyperinsulinism and insulin resistance in the Kazakh population. No interaction was identified between LPL Ser447Ter, ADRB2 Gln27Glu, AGT Thr174Met and AGTR1 A1166C. Therefore, the results indicated that haplotype combinations were not associated with insulin resistance.

Associations Between Polymorphisms of Endothelial Nitric Oxide Synthase, Matrix Metalloproteinase 3, Angiotensinogen, and Angiotensin II Type 1 Receptor and Risk of Restenosis After Percutaneous Coronary Intervention: A Meta-analysis

PurposePrevious studies have reported controversial results regarding the risk of restenosis with polymorphisms of endothelial nitric oxide synthase (eNOS), matrix metalloproteinase 3 (MMP-3), angiotensinogen (AGT), and angiotensin II type 1 receptor (AT1R) after percutaneous coronary intervention (PCI). This study aimed to summarize the association between these polymorphisms and risk of restenosis after PCI. MethodsWe searched the electronic databases of PubMed, Embase, Cochrane's Library, and ClinicalTrials.gov for studies on the association of eNOS, MMP-3, AGT, and AT1R polymorphisms with restenosis. FindingsA total of 17 studies (7781 patients) were analyzed, including 5 studies on eNOS G298A (n = 912), 5 studies on MMP3 5A/6A (n = 4519), 6 studies on AGT M235T (n = 1801), and 7 studies on AT1R A1166C (n = 2477). For the G298A variant of the eNOS gene, the allele odds ratio (OR) was 1.685 (95% CI, 1.269–2.338; P < 0.001), the heterozygote OR was 2.144 (95% CI, 1.490–3.085; P < 0.001), the dominant OR was 2.078 (95% CI, 1.462–2.954; P < 0.001), and the overdominant OR was 0.496 (95% CI, 0.348–0.706; P < 0.001). For the 5A/6A variant of the MMP3 gene, the heterozygote OR was 0.839 (95% CI, 0.722–0.975; P = 0.022), the dominant OR was 0.846 (95% CI, 0.733–0.976; P = 0.022), and the overdominant OR was 1.141 (95% CI, 1.001–1.301; P = 0.049). For the M235T variant of the AGT gene, the heterozygote OR was 1.594 (95% CI, 1.179–2.155; P = 0.002), the dominant OR was 1.437 (95% CI, 1.077–1.918; P = 0.014), and the overdominant OR was 0.694 (95% CI, 0.555–0.869; P = 0.001). Positive results were observed in the AT1R gene A1166C polymorphism under 3 models (homozygote OR = 2.009; 95% CI, 1.433–2.816; P < 0.001; recessive OR 1.874; 95% CI, 1.353–2.595; P < 0.001; and dominant OR = 1.350; 95% CI, 1.105–1.649; P = 0.003). ImplicationsThe G298A variant of eNOS, the 5A/6A variant of MMP3, the M235T variant of AGT, and the A1166C variant of A1TR may increase the risk of restenosis after PCI.

The association between angiotensin II type 1 receptor A1166C gene polymorphism and the risk of essential hypertension: a meta-analysis

BackgroundSince first reported having the association with essential hypertension, angiotensin II type 1 receptor (AT1R) A1166C was globally investigated worldwide. However, controversy was found. Furthermore, previous meta-analyses did not adequate to clarify the precise correlation due to some limitations. Therefore, we aimed to perform a meta-analysis concerning the association between AT1R A1166C single-nucleotide polymorphism (SNP) and the risk of essential hypertension with eliminating the limitations of previous studies.MethodsA meta-analysis was conducted from February to March 2019. Some information related to sample size of hypertension and control groups and genotype frequencies of hypertension and control groups were extracted from each study. Data were analyzed using fixed or random effect model to determine the overall correlation.ResultsA total of 45 papers consisting of 11911 cases and 1340 controls were enrolled for the study. Our overall analysis showed that C allele and AC genotype of AT1R A1166C was associated with 1.18-fold and 1.15-fold respectively increased risk of essential hypertension, while the decreased risk of essential hypertension was observed in A allele and AA genotype. In sub-group analysis, increased risk of essential hypertension was found in C allele, AC genotype, and CC genotype of both Asian population and PCR-RFLP sub-groups, while decreased risk was observed in A allele and AA genotype.ConclusionsOur meta-analysis reveals that AT1R A1166C remains a valuable SNP having an association with the risk of essential hypertension.

Risk and severity of psoriasis vulgaris in relation to angiotensin II type 1 receptor gene polymorphism and metabolic syndrome.

BackgroundPsoriasis vulgaris is a chronic inflammatory and proliferative skin disease, characterized by the formation of itchy, erythematous skin patches or plaques. Patients with psoriasis are at an increased risk of developing metabolic syndrome, including obesity, hypertension, diabetes, and atherosclerosis. Recently, angiotensin II (Ang II) has been reported to be associated with the development of psoriasis. Ang II not only increases the blood pressure but is also a potent proinflammatory modulator and functions through interaction with angiotensin II type 1 receptor (AT1R). Moreover, it is hypothesized that the AT1R gene expression could be correlated with the severity of psoriasis and/or metabolic syndrome.AimWe examined the association of Ang II type 1 receptor (AT1R) A1166C gene polymorphisms and metabolic syndrome with the severity of psoriasis.Patients and methodsThe present case-control study included 25 patients with psoriasis vulgaris and 25 healthy subjects in Egypt. The psoriasis lesions in the patient group were assessed using the psoriasis area and severity index (PASI) score. The AT1R polymorphism A1166C (rs5186) was studied using restriction fragment length polymorphism (RFLP) and polymerase chain reaction (PCR) amplification of the gene from the whole blood sample in both groups. Serum lipid profile and blood sugar levels were assessed post 12 h and 8 h fasting, respectively, in both groups. The severity of metabolic syndrome was evaluated using the severity score.ResultsThe results of the present study demonstrated that the AT1R A1166C gene polymorphisms increased the risk of developing psoriasis in the Egyptian population. We found that 70% of patients with AC genotype and 100% of patients CC genotype reported a PASI score >20 and were considered to be severe cases with a statistically significant difference as compared with patients with AA genotype (p=0.003). In addition, a high statistically significant difference (p=0.001) existed among AT1R genotypes with respect to the percentage of metabolic syndrome in psoriasis patients. Similarly, a statistically significant difference (p=0.004) among AT1R genotypes with respect to metabolic score was found, with the highest level of score and percentage observed in patients with CC genotype than in patients with AC genotype. The lowest level was present among those with AA genotype.ConclusionPatients with psoriasis expressing the C allele of AT1R1166 are susceptible to developing metabolic syndrome and have higher PASI scores as compared with patients carrying the A allele.

Association between AGTR1 A1166C polymorphism and the susceptibility to diabetic nephropathy: Evidence from a meta-analysis.

Background:Diabetic nephropathy (DN) is a common complication in patients with diabetic mellitus (DM). Growing evidences have demonstrated that the polymorphisms of angiotensin II receptor type 1 (AGTR1) showed significant association with DN onset, but no consensus has been achieved yet. Therefore, we performed this meta-analysis to combine the findings of previous researches for a more comprehensive conclusion.Methods:Eligible publications were identified through electronic databases. The intensity of the correlation between AGTR1 A1166C polymorphism and DN susceptibility was evaluated through calculating pooled odds ratios (ORs) with their 95% confidence intervals (95% CIs). Heterogeneity among included studies was examined with Q test. When P-value less than .05, significant heterogeneity presented, random-effects model was used to calculate the pooled ORs, otherwise, the fixed-effects model was used. Stratification analyses were also performed based on ethnicity and the type of DM.Results:Seventeen eligible articles were finally included in the present meta-analysis. The analysis results showed that AGTR1 A1166C polymorphism was significantly related to increased risk of DN under CC versus AA (OR = 1.723, 95% CI = 1.123–2.644), CC + AC versus AA (OR = 1.179, 95% CI = 1.004–1.383), CC versus AA + AC (OR = 1.662, 95% CI = 1.112–2.486), and C versus A (OR = 1.208, 95% CI = 1.044–1.397) genetic models. Additionally, a similar result was also found in Asian and T2DM (type 2 diabetic mellitus) groups after subgroup analyses of ethnicity and DM type.Conclusion:AGTR1 A1166C polymorphism may increase the susceptibility to DN, especially in Asians and T2DM population.

Renin-Angiotensin-Aldosterone System Gene Polymorphisms and Type 2 Diabetic Nephropathy in Asian Populations: An Updated Meta-analysis.

The association of polymorphisms in the renin-angiotensin-aldosterone system candidate genes, namely Angiotensin-Converting Enzyme (ACE) Insertion/Deletion (I/D), Angiotensinogen (AGT) M235T and Angiotensin II Receptor Type 1 (AGTR1) A1166C with Diabetic Nephropathy (DN) has been studied for decades. This meta-analysis aimed to assess the updated pooled effects of these polymorphisms with DN among Asian populations with type 2 diabetes mellitus. The PubMed electronic database was searched without duration filter until August 2017 and the reference list of eligible studies was screened. The association of each polymorphism with DN was examined using odds ratio and its 95% confidence interval based on dominant, recessive and allele models. Subgroup analyses were conducted based on region, DN definition and DM duration. In the main analysis, the ACE I/D (all models) and AGTR1 A1166C (dominant model) showed a significant association with DN. The main analysis of the AGT M235T polymorphism did not yield significant findings. There were significant subgroup differences and indication of significantly higher odds for DN in terms of DM duration (≥10 years) for ACE I/D (all models), AGT M235T (recessive and allele models) and AGTR1 A1166C (recessive model). Significant subgroup differences were also observed for DN definition (advanced DN group) and region (South Asia) for AGTR1 A1166C (recessive model). In the Asian populations, ACE I/D and AGTR1 A1166C may contribute to DN susceptibility in patients with T2DM by different genetic models. However, the role of AGT M235T needs to be further evaluated.

The Gene Variants of Maternal/Fetal Renin-Angiotensin System in Preeclampsia: A Hybrid Case-Parent/Mother-Control Study

Preeclampsia (PE) is a common pregnancy-related complication, and polymorphisms in angiotensinogen (AGT), angiotensin-converting enzyme (ACE), and angiotensin II type 1 receptor (AT1R) are believed to contribute to PE development. We implemented a hybrid study to investigate the influence of maternal and fetal ACE I/D, ACE G2350A, AGT M235T, AGT T174M, and AT1R A1166C polymorphisms on PE in Han Chinese women. Polymorphisms were genotyped in 1,488 subjects (256 patients experiencing PE, along with their fetuses and partners, and 360 normotensive controls with their fetuses). Transmission disequilibrium tests revealed that ACE I/D (P = 0.041), ACE G2350A (P = 0.035), and AT1R A1166C (P = 0.018) were associated with maternal PE. The log-linear analyses revealed that mothers whose offspring carried the MM genotype of AGT M235T had a higher risk of PE (OR = 1.54, P = 0.010), whereas mothers whose offspring carried the II genotype of ACE I/D or the GG genotype of ACE G2350A had a reduced risk (OR = 0.58, P = 0.039; OR = 0.47, P = 0.045, respectively). Our findings demonstrate that fetal ACE I/D, ACE G2350A, AGT M235T, and AT1R A1166C polymorphisms may play significant roles in PE development among pregnant Han Chinese women.

Angiotensin II Type 1 Receptor Gene A1166C Polymorphism Was Not Associated With Acute Coronary Syndrome in an Iranian Population.

BackgroundThere are very limited data for Iranian populations on the predisposing genetic factors for acute coronary syndrome (ACS).ObjectivesThe objective of the present study was to investigate the association of the angiotensin II type 1 receptor (AT1R) gene polymorphism and ACS in an Iranian population.Patients and MethodsThis cross-sectional study was conducted among 263 subjects (97 men and 166 women). Patients (n = 128) aged 30 - 80 years with chest pain were recruited from the emergency department of Ghaem Hospital (Mashhad, Iran). A 12-lead electrocardiograph plus creatine kinase MB (CK-MB) levels were used as the basis for the diagnosis of myocardial ischemia. The control group was selected from age-matched healthy subjects (n = 135). Non-enzymatic kits were used for extraction of DNA from blood samples. Polymerase chain reaction (PCR) was performed to amplify the DNA fragments. For restriction fragment length polymorphism (RFLP) determination, the DdeI enzyme was used to digest the amplified DNA fragments. Statistical analyses were performed using SPSS version 13.0.ResultsThere was no statistical difference in the genotype frequency of patients and healthy subjects with regard to age and gender (P > 0.05).ConclusionsThe AT1R A1166C polymorphism appeared not to be associated with the presence of ACS in the population studied.

AT1R A1166C variants in patients with type 2 diabetes mellitus and diabetic nephropathy.

Background: There are inconsistent reports related to the role of angiotensin II type 1 receptor (AT1R) on the risk of type 2 diabetes mellitus (T2DM) and its renal complications. Objectives: To identify the association between AT1R A1166C variants with the risk of T2DM and also with diabetic nephropathy (DN). Patients and Methods: In a case-control study, the AT1R A1166C polymorphism was detected in 135 T2DM patients with and without DN and in 98 healthy subjects from Western Iran. The genotypes of AT1R A1166C polymorphism were detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Results: The frequencies of AT1R A1166C genotypes and alleles were not significantly difference between patients with and without DN and controls. The frequencies of rare allele of 1166 C were 10%, 16.5%, 15.9% and 15.3% in micro-, macro- and normo-albuminuric patients and in healthy individuals, respectively ( P > 0.05). The systolic blood pressure and serum creatinine level in DN patients were significantly higher in carriers of AT1R CC compared to carriers of AT1R AA genotype. In the presence of uncontrolled hyperglycemia (HbA1c > 7.5%), there was a trend toward increased risk of macro-albuminuria in carriers of AC+CC genotype (OR=3.66, [95% CI: 0.81-16.58], P = 0.092). Conclusions: Our study indicated the absence of an association between AT1R A1166C polymorphism with the risk of T2DM and DN. It seems in carriers of AT1R C allele systolic blood pressure and serum creatinine level to be higher compared to the A allele carriers.

Association of AGTR1 gene A1166C polymorphism with the risk of heart failure: a meta-analysis.

The aim of this study was to investigate the correlation between the A1166C polymorphism in the angiotensin II type 1 receptor (AT1R) gene and heart failure (HF) risk using meta‑analysis. The PubMed database was searched, and data were extracted independently by two reviewers. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to assess the strength of the associations. Statistical analysis was performed using the STATA 12.0 software. The results of the meta‑analysis showed no significant association between the AT1R A1166C polymorphism and HF risk (AA vs CC: OR = 0.72, 95%CI = 0.31-1.68; AA vs AC: OR = 0.78, 95%CI = 0.52-1.18; dominant model: OR = 1.37, 95%CI = 0.92-2.04; recessive model: OR = 0.73, 95%CI = 0.30-1.75). In the subgroup analysis by ethnicity, the results also showed no significant association between A1166C polymorphism and susceptibility to HF in both Caucasian and Asian populations. In conclusion, this meta-analysis suggests that the A1166C polymorphism in AT1R may not be associated with susceptibility to HF. Further large and well-designed studies are needed to confirm these conclusions.

Susceptibility and progression of end stage renal disease are not associated with angiotensin II type 1 receptor gene polymorphism

Context: The role of the angiotensin II type 1 receptor (AT1R) gene polymorphism, A1166C, has been shown to be associated with end stage renal disease (ESRD) and its progression. There is also some evidence that HLA class II alleles are associated with ESRD independent of other factors. Objective: To examine the association between AT1R gene polymorphism in the susceptibility and progression to ESRD in patients with chronic renal failure and to investigate if the AT1R genotypes and HLA-DR alleles predict the time to ESRD. Materials and methods: Genotyping was performed in 50 ESRD patients and 44 control subjects for the AT1R A1166C gene polymorphism using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). ESRD patients were examined for HLA-DRB1 alleles according to a reverse hybridization line probe assay. Results: Allele and genotype frequencies of the AT1R polymorphism did not differ significantly between ESRD patients and controls. Furthermore, there was no association between the AT1R gene polymorphism or HLA-DRB1 alleles with the time to the occurrence of end stage failure. Discussion and Conclusion: We concluded that the AT1R genotype does not contribute to the genetic susceptibility of ESRD and is not associated with progression of chronic kidney failure to ESRD.

Association of angiotensin II type-1 receptor A1166C gene polymorphism with the susceptibility of end-stage renal disease

Association between angiotensin II type-1 receptor (AT1R) A1166C gene polymorphism and end-stage renal disease (ESRD) risk is still controversial. This meta-analysis was performed to evaluate the association of AT1R A1166C gene polymorphism with ESRD susceptibility. The search was performed in the databases of PubMed, Embase and Cochrane Library as of 1 May 2012, and the eligible investigations were recruited for this meta-analysis. Nineteen literatures were identified for the analysis of association between AT1R A1166C gene polymorphism and ESRD susceptibility. There was no association between AT1R A1166C gene polymorphism and ESRD susceptibility for overall populations, Caucasians, Asians and Turkish population. Interestingly, CC genotype was associated with a higher risk of ESRD in Africans (OR = 3.36, 95% CI: 1.42–7.99, p = 0.006). However, C allele and AA genotype were not associated with the ESRD risk in African population. In conclusion, CC genotype might be a risk factor for the ESRD susceptibility in African population. However, more case-control association investigations on larger, stratified populations are required in the future.

Genotypes of renin-angiotensin system and plasma adiponectin concentration in kidney transplant patients

Low plasma adiponectin concentration was recently recognized as a novel risk factor for new-onset diabetes after transplantation. Pharmacological modulation of the renin-angiotensin system activity and genetic predisposition were shown to have an influence on plasma adiponectin level. Therefore the aim of this study is to analyze the association between angiotensin-converting enzyme (ACE) I/D, angiotensin II type 1 receptor (AT1R) A1166C and angiotensinogen (AGT) M235T genotypes and plasma adiponectin concentration as well as insulin resistance in a cohort of kidney transplant patients. AGT M235T, ACE I/D and AT1R A1166C genotyping and plasma adiponectin and insulin concentrations assessment were performed in 372 patients with functioning kidney allograft (eGFR >20 ml/min/1.73 m2) from 2 transplant centres. Females with II ACE I/D genotype had a significantly higher plasma adiponectin concentration than the ID+DD subgroup, which could partially be explained by a lower BMI in the II subgroup. Males with TT genotype of the AGT M235T gene polymorphism (and higher BMI) had higher plasma concentration of insulin and HOMAIR values than those in the MT+MM subgroup. A multiple regression analysis revealed that only female sex (b=0.239), BMI (b=–0.208) and ACE II genotype (b=0.129) were significantly associated with plasma adiponectin concentration variability. A similar analysis for HOMA-IR showed that its variability was associated with BMI (b=0.333), eGFR (b=–0.115) and plasma adiponectin concentration (b=–0.064) irrespective of any of the analyzed genotypes. Plasma adiponectin concentration, but not insulin resistance, seems to be modulated only by ACE I/D polymorphism in kidney transplant patients. Polymorphisms of the other renin-angiotensin system components do not influence plasma adiponectin concentration or insulin resistance in these patients.

Angiotensin II type I receptor A1166C polymorphism increases the risk of pregnancy hypertensive disorders: Evidence from a meta-analysis

Pregnancy hypertensive disorders (PHDs) are considered to be a multifactorial and multisystemic disorder with a genetic predisposition. Alterations in the renin-angiotensin system are considered to play a significant role in the pathogenesis of the PHDs. However, results from published studies on the association between the angiotensin II type-1 receptor (AT1R) A1166C (rs5186) gene polymorphism and the risk of PHDs are conflicting. The aim of this meta-analysis was to investigate whether an association exists between AT1R A1166C gene polymorphism and PHDs in epidemiologic studies. We searched the PubMed, China National Knowledge Infrastructure (CNKI), and Chinese Biomedicine Literature (CBM) databases from their inception to July 2012. A total of 18 case-control studies, including a total of 1635 cases and 1934 controls, were available for this analysis. A significantly positive correlation was observed between the C allele and the AC/CC genotypes with PHDs in an overall comparison. In the subgroup analysis by ethnicity, the results suggested that the C allele and the AC/CC genotypes were associated with risk of PHDs in Asians. Our findings indicate that the AT1R gene 1166C allele and the AC/CC genotypes were positively associated with the PHDs, especially in Asians. However, well-designed multicenter studies with a larger sample size should be conducted to confirm the results.

A systematic review and meta-analysis of the association between angiotensin II type 1 receptor A1166C gene polymorphism and myocardial infarction susceptibility

Many reported studies have been conducted to investigate the association of angiotensin II type 1 receptor (AT1R) A1166C gene polymorphism with myocardial infarction (MI) susceptibility. However, the results from those reports are still conflicting. This meta-analysis was performed to study the relationship between AT1R A1166C gene polymorphism and MI risk. The databases of PubMed, Embase, and Cochrane Library were searched as of 1 March 2012, and eligible investigations were recruited into this meta-analysis. Eighteen investigations were identified for the analysis of association between AT1R A1166C gene polymorphism and MI risk, 11 in Caucasians, three in Asians, two in Africans, one in the population of Brazil and one in the population of Durban, South Africa . There was a marked association between AT1R C allele and MI susceptibility for overall populations (odds ratio (OR)=1.12, 95% confidence interval (CI): 1.01-1.25, p=0.03), and AT1R AA genotype was associated with a lower risk of MI in overall populations (OR=0.87, 95% CI: 0.78-0.98, p=0.02). However, AT1R A1166C gene polymorphism was not associated with MI risk in the sub-groups of Caucasians, Asians, Africans, Brazil and Durban populations. C allele is a risk factor for the MI susceptibility in overall populations, and AA genotype might be a protective factor against the MI risk in overall populations. However, more case-control association investigations on larger, stratified populations are required in the future.

Association of polymorphisms in angiotensin and aldosterone synthase genes of the renin–angiotensin–aldosterone system with high-altitude pulmonary edema

Studies on different populations have suggested variability in individual susceptibility to altitude sickness depending on genetic makeup. The renin-angiotensin-aldosterone system (RAAS) pathway plays a key role in regulation of vascular tone and circulatory homeostasis. The present study was undertaken to investigate the possible association of the RAAS in the development of high-altitude pulmonary edema (HAPE) in lowlanders exposed to high altitude. Three categories of subjects were selected: individuals who developed HAPE on acute induction to high altitude (HAPE); individuals tolerant to high-altitude exposure who showed no symptoms of HAPE (resistant controls; rCON); and natives of high altitude (HAN). Genetic variants in the genes of the RAAS such as renin (REN), angiotensin (AGT), angiotensin-converting enzyme (ACE), aldosterone synthase (CYP11B2) and angiotensin II receptor type 1 (AGTR1) have been investigated. The T174M polymorphism in AGT showed a significant difference in HAPE and HAN and also HAN and controls. Also, genotyping in the CYP11B2 T-344C promoter region resulted in a significant difference between HAPE and HAN both at genotypic and allelic levels. The genotypic difference was statistically insignificant for the AGTR1 A1166C 3' UTR. The present investigation demonstrates a possible association between the polymorphisms existing in the RAAS pathway T174M and CYP11B2 C-344T and sensitivity of an individual to develop HAPE. The results also indicate the existence of ethnic variation between the HAN and the other two groups comprising lowlanders.

Association between two genetic polymorphisms of the renin-angiotensin-aldosterone system and diabetic nephropathy: a meta-analysis

The widely studied candidate genes of the renin-angiotensin-aldosterone system, angiotensinogen (AGT), and angiotensin II receptor type 1 (AGTR1), are implicated in the development of diabetic nephropathy (DN). A number of studies have evaluated the association between the functional polymorphisms, AGT M235T and AGTR1 A1166C, and DN risk with conflicting results. The present meta-analysis was performed to estimate the overall risk of these polymorphisms associated with DN on 4,377 DN cases and 4,905 controls from 34 published case-control studies by searching electronic databases and reference lists of relevant articles. We examined the association between each polymorphism and the risk of DN by odds ratio (OR) with 95% confidence intervals (95% CI) and calculated the ORs for different genetic model. In addition, stratification analysis by ethnicity and diabetes mellitus (DM) type was conducted. In this meta-analysis, we failed to find any significant main effects in both overall analysis and stratified analysis for the AGT M235T. However, the overall analysis detected a significant association between the AGTR1 A1166C and the risk of DN for the CC compared with the AA and dominant genetic model (CC vs. AA: OR = 2.10, 95% CI: 1.00-4.44; dominant model: OR = 2.11, 95% CI: 1.06-4.23). In subgroup analysis, only patients with T2DM showed significant association for CC vs. AA model and dominant model (CC vs. AA: OR = 3.31, 95% CI: 1.21-9.08; dominant model: OR = 3.50, 95% CI: 1.41-8.69). This study suggests that the AGTR1 A1166C polymorphism may contribute to DN development, particularly in T2DM patients.

Interplay Between miR-155, AT1R A1166C Polymorphism, and AT1R Expression in Young Untreated Hypertensives

A silent polymorphism (+1166 A/C single-nucleotide polymorphism) localized in the 3'-UTR (untranslated region) of the human angiotensin II type-1 receptor (AT1R) has been associated with hypertension and cardiovascular complications. The +1166 A/C is recognized by a specific microRNA-155 (miR-155), which is base-pairing complementary with the +1166 A-allele but not with the mutant +1166 C allele. Aim of our study was to investigate the interplay between miR-155 and AT1R protein expression. Sixty-four subjects were selected for the +1166 A/C from the cohort of hypertensives (n = 573) of the Hypertension and Ambulatory Recording Venetia Study (HARVEST): 25 were homozygous for the 1166 A allele, 20 heterozygous, and 19 homozygous for the 1166 C allele. miR-155 expression was significantly decreased in subjects with CC genotype in comparison to AA and AC genotype. AT1R protein expression was significantly increased in the CC group in comparison to AA and AC (P < 0.01) although AT1R mRNA expression was not significantly different in the three groups. AT1R protein expression was positively correlated with systolic and diastolic blood pressure and negatively correlated with miR-155 expression level. Plasma transforming growth factor-β1 (TGF-β1) may have a modulator role in the interplay between miR-155 and AT1R protein expression as it was correlated negatively with miR-155 expression and positively with AT1R protein expression in subjects with CC genotype. The interplay between miR-155 expression, +1166C polymorphism, and AT1R protein expression may have a role in the regulation of blood pressure.

Early Inflammatory and Metabolic Changes in Association With AGTR1 Polymorphisms in Prehypertensive Subjects

The Seventh Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure in 2003 created a prehypertension category for persons with blood pressures ranging from systolic blood pressure (SBP) of 120-139 mm Hg or diastolic blood pressure (DBP) from 80 to 89 mm Hg, due to increased risk of cardiovascular disease. Our study utilized the University of California-San Diego (UCSD) Twin Hypertension Cohort. We measured comprehensive plasma cholesterol levels and metabolic (glucose, insulin, leptin) and inflammatory markers (interleukin-6 (IL-6), C-reactive protein (CRP), free fatty acids) to determine the differences between normotensive and prehypertensive subjects. Additionally, we determined whether angiotensin II receptor type-1 (AGTR1) polymorphisms, previously associated with hypertension, could predict prehypertension. A total of 455 white subjects were included in the study (mean age 37.1 years). Prehypertensive subjects were older with greater body mass index (BMI) than the normotensives, and after adjusting for sex and age, had greater plasma glucose, insulin, and IL-6. The common AGTR1 A1166C (rs5186) polymorphism in the 3'-UTR region, particularly the presence of the 1166C allele, which fails to downregulate gene expression, predicted greater likelihood of being in the prehypertension group and higher SBP. A lesser-studied polymorphism in intron-2 of AGTR1 (A/G; rs2276736) was associated with plasma high-density lipoprotein (HDL) and apolipoprotein A-1. In a subgroup analysis of nonobese subjects (N = 405), similar associations were noted. Prehypertensive subjects already exhibit early pathophysiologic changes putting them at risk of future cardiovascular disease, and AGTR1 may also contribute to this increased risk. Further investigation is needed to confirm these findings and the precise molecular mechanisms of action.