Association of the angiotensinogen M235T and angiotensin-converting enzyme insertion/deletion gene polymorphisms in Turkish type 2 diabetic patients with and without nephropathy

OBJECTIVE: Recent studies have suggested an association between a deletion variant of the angiotensin-converting enzyme (ACE) gene and diabetic nephropathy. However, this finding has not been confirmed by all investigators. Furthermore, an M235T variant of the angiotensinogen (AGT) gene has been associated with hypertension, an important risk factor for the development and progression of diabetic nephropathy. RESEARCH DESIGN AND METHODS: We investigated the relationship of the ACE insertion/deletion (I/D) and AGT M235T gene polymorphisms in Turkish patients with type 2 diabetes mellitus (DM) with and without diabetic nephropathy. A total of 102 individuals were screened for the presence of the ACE I/D and AGT M235T polymorphism: 46 individuals who had type 2 DM with diabetic nephropathy and, as controls, 56 individuals who had type 2 DM without diabetic nephropathy. Gene polymorphisms were determined by the specific melting temperature (T(m)) values of the resulting amplicons after real-time online polymerase chain reaction and melting curve analysis. RESULTS: The frequencies of the ACE DD, ID, and II genotypes were 34.8%, 37.0%, and 28.3%, respectively, among type 2 diabetic patients with nephropathy, and 33.9%, 42.9%, 23.2%, respectively (P=.788), in the control subjects without diabetic nephropathy. On the other hand, the frequencies of the AGT MM, MT, and TT genotypes among the same groups were 26.1%, 52.2%, 21.7% and 26.8%, 57.1%, 16.1%, respectively (P=.758). CONCLUSIONS: There were no differences in the frequencies of the AGT M235T and ACE I/D genotypes between Turkish patients with type 2 DM with and without nephropathy.     

血管紧张素原基因多态性与肥厚型心肌病的相关性分析

目的 探讨血管紧张素原(AGT)基因的单核苷酸多态性(SNP)位点A943580G与肥厚型心肌病(HCM)的相关性.方法 用PCR-RFLP方法对225个HCM病人和243个正常人的AGT的SNP位点A943580G进行基因分型(此位点与黑色人种中的高血压病人的最大早期充盈速度有关).结果 携带AA和AG基因型的HCM病人的左心室流出道梗阻率明显高于GG基因型的梗阻率(30.1%比17.0%,P＜0.05).通过对发病年龄,性别,室间隔厚度,HCM家族史以及家族猝死史进行调整后,携带A等位基因(AA AG)的HCM病人左心室流出道梗阻率要高于GG基因型病人(OR=2.4,95%CI 1.2 to 4.8).结论 AGT的A等位基因可能是HCM病人发生左心室流出道梗阻的危险因子.     

肾素-血管紧张素-醛固酮系统基因多态性与大动脉粥样硬化性卒中的相关性:中国南方汉族人群研究

目的 研究肾素-血管紧张素-醛固酮系统血管紧张素原(angiotensinogen,AGT)基因M235T、血管紧张素Ⅱ1型受体(angiot ensinⅡtype 1 receptor,AGTR1)基因A1166C、醛固酮合酶( aldosterone synthase,CYP11B2)基因- 344C/T多态性与中国南方汉族人群大动脉粥样硬化性卒中(large-artery atherosclerosis,LAA)的相关性.方法 采用聚合酶链反应和基因测序技术对中国南方汉族LAA患者和正常对照者AGT基因M235T、ATGR1基因A1166C和CYP11B2基因- 344C/T多态性进行基因分型,并通过二分类logistic回归分析确定这3种基因多态性与LAA的相关性.结果 共纳入LAA患者107例和142名健康对照者.LAA组AGT基因235TT基因型(66.36％对50.70％,x2=6.122,P=0.047)和T等位基因(79.44％对70.07％,x2=5.581,P=0.018)频率显著高于对照组,AGTR1基因1166CC基因型(0％对0％,x2=1.494,P=0.222)和C等位基因(7.48％对4.93％,x2=1.399,P=0.237)频率与对照组无显著性差异,CYP11B2基因- 344CC基因型(9.35％对4.23％,x2=3.603,P=0.165)和C等位基因(27.10％对26.06％,x2=0.069,P=0.793)频率与对照组亦无显著性差异.二分类logistic回归分析显示,这3种基因多态性与单纯性LAA患病均无显著相关性.合并高血压的LAA患者AGT基因235TT基因型(68.00％对41.90％,x2=12.446,P=0.002)和T等位基因(79.33％对64.76％,x2=8.993,P=0.003)频率均显著高于血压正常对照组,logistic回归分析显示,暴露于TT基因型的优势比(odds ratio,OR)为2.153[ 95％可信区间(confidence interval,CI)0.789 ～5.872],T等位基因的OR值为2.089(95％ CI1.285 ～3.396).结论 AGT基因M235T多态性与南方汉族人群单纯性LAA无关,但可能与合并高血压的LAA患病风险相关;CYP11B2基因- 344C/T多态性和AGTR1基因A1166C多态性与南方汉族人群LAA发病无关.     

Role of tagged SNPs of the AGT gene in causing susceptibility to essential hypertension

Aim: Angiotensinogen (AGT) is one of the candidate genes that has been extensively investigated for association of its variants with essential hypertension. Studies focusing on the contribution of tagged single nucleotide polymorphisms (SNPs) in the AGT gene are limited and lacking from Indian population. Hence, the present study was carried out to examine the role of five tagged SNPs viz., g.6147G>A (rs7539020), g.5978A>G (rs2493134); g.6241T>C (rs1078499), g.7781G>T (rs11122577), and g.5855G>A (rs3789678) in the development of hypertension. Materials and Methods: 202 hypertensives and 222 normotensives were screened for five tagged SNPs using the method of polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Results: The present study revealed significant association of g.5855G>A polymorphism with essential hypertension in different logistic regression models wherein protection was conferred by g.5855G>A against developing the condition. The polymorphism led to the creation of new exonic splicing enhancer and destruction of exonic splicing silencer site thereby enhancing the process of mRNA splicing. The haplotypes AGTG and GACG were found to have a significant protective effect. Other polymorphisms did not show any significant association with hypertension. Conclusion: The present study is the first one to report the protective role of g.5855G>A polymorphism in the development of essential hypertension. The results reflect possibility of ethnic variation in the contribution of g.5855G>A polymorphism of the AGT gene to essential hypertension.     

血管紧张素原基因T174M和血管紧张素转换酶基因I/D多态性与急性心肌梗死的相关性

目的探讨中国汉族人群血管紧张素转换酶和血管紧张素原基因型的分布及其与急性心肌梗死的关系。方法应用聚合酶链反应技术,对112例急性心肌梗死患者、128例非冠心病患者血管紧张素转换酶I/D多态性及血管紧张素原T174M多态性进行检测。结果血管紧张素转换酶基因型分布及等位基因频率在病例组及对照组间差异有显著性(P<0.01)。病例组和对照组血管紧张素原基因型及等位基因频率总体分布差异亦有显著性(P<0.05)。联合基因分析显示,急性心肌梗死组血管紧张素转换酶DD基因型 血管紧张素原174MM基因型频率显著高于对照组(P<0.01),具有该联合基因型者发生冠心病的风险比数比(OR=8.467)明显高于单独具有血管紧张素转换酶DD基因型(OR=2.558)或血管紧张素原174MM基因型(OR=6.176)者。结论血管紧张素原T174M基因多态性中M等位基因和血管紧张素转换酶I/D基因多态性基因中的D等位基因是中国汉族人群冠心病发病的危险因素之一。同时具有血管紧张素转换酶DD型及血管紧张素原174MM型发生冠心病的相对风险显著高于单基因血管紧张素转换酶DD型及单基因血管紧张素原174MM型。     

Tagesprofile von Plasmaaldosteron,-Cortisol, -Renin, -Angiotensinogen und -Angiotensinasen bei Normalpersonen

Zusammenfassung An 6 normalen männlichen Freiwilligen im Alter von 20–26 Jahren wurden Plasmacortisol und -renin stündlich, Plasmaaldosteron, -angiotensinogen und -angiotensinasen alle 3 Std über jeweils 24 Std unter Kontrollbedingungen und anschließend unter Suppression der ACTH-Freisetzung durch Dexamethason gemessen.Die höchsten Cortisolspiegel fanden sich gegen 7 Uhr, die niedrigsten zwischen 21 und 1 Uhr. Die Gabe von Dexamethason führte zu konstant niedrigen Cortisolkonzentrationen.Aldosteron war unter Kontrollbedingungen und unter Dexamethason gegen 4 Uhr am höchsten und zeigte niedrigste Werte zwischen 16 und 22 Uhr. Zwischen den mittleren Aldosteronkonzentrationen entsprechender Zeitpunkte der Kontroll- und der Dexamethasonperiode bestanden keine signifikanten Unterschiede.Ähnlich dem Aldosteron zeigte das Plasmarenin Maximalwerte gegen 4 Uhr. Alle Mittelwerte entsprechender Zeitpunkte zwischen 7 und 23 Uhr und die jeweiligen 24 Std-Mittelwerte jedes einzelnen Probanden waren unter dem Einfluß von Dexamethason signifikant erhöht.Für die Existenz circadianer Rhythmen des Angiotensinogens und der Angiotensinasen konnte kein Anhalt gewonnen werden. Dexamethason bewirkte keine signifikanten Veränderungen dieser Parameter.Die Ergebnisse deuten darauf hin, daß die circadianen Rhythmen von Aldosteron und Renin miteinander vergleichbar, jedoch nicht exakt mit dem des Cortisols synchronisiert sind. Unter der Hemmung der ACTH-Freisetzung durch Dexamethason steigt die Reninaktivität an, der Aldosteronspiegel bleibt unverändert. Angiotensinogen und die Angiotensinasen, Parameter, die die aktive Konzentration des Angiotensin II beeinflussen können, scheinen an der Regulation des Aldosterons nicht beteiligt zu sein.Die Ergebnisse wurden auf dem 21. Symposiom der Deutschen Gesellschaft für Endokrinologie und auf dem Symposiom Aktuelle Probleme der Hochdruck- und Nierenkrankheiten anläßlich des 75. Geburtstages von Herrn Prof. Dr. E. Wollheim vorgetragen.     

Association of Angiotensin-converting enzyme and angiotensinogen gene polymorphisms with preeclampsia

We tested the hypothesis that angiotensin-converting enzyme (ACE) and angiotensinogen gene polymorphism influence the incidence, development and outcome of preeclampsia. Subjects were recruited from 90 Korean patients with preeclampsia during pregnancy and 98 age-matched controls. After isolation of DNA, polymerase chain reactions (PCR) were carried out to detect polymorphism of the ACE and angiotensinogen. M235T and T174M genotypes of angiotensinogen were determined by digestion with restriction enzyme endonuclease Tth 111-I and NCo I, respectively. The frequency of DD genotype was significantly greater in preeclampsia (0.36) than in controls (0.14) (p<0.05). The frequency of D allele was 0.55 in preeclampsia and 0.40 in controls (p<0.05). There were no differences in the onset of preeclampsia and pregnancy outcomes according to the ACE genotypes. There was no difference in the frequency of a allele of angiotensinogen M235T between the groups (0.79:0.78 in preeclampsia : controls). The frequency of T allele of angiotensinogen T174M gene was slightly increased, but not significantly, in preeclampsia (0.11) than in controls (0.07). In a multivariate analysis, only ACE genotype was associated with the development of preeclampsia (beta=0.27, p=0.05). In conclusion, a molecular variant of ACE, but not angiotensinogen, gene is associated with preeclampsia in Korean women.     

Influence of the angiotensinogen gene on the ovulatory capacity of mice

Objective: The tissue-bound ovarian renin-angiotensin system (OVRAS) is critically involved in ovulation in humans and rodents. Mice with disruption and overexpression of the angiotensinogen gene (Agt) have been previously generated. We investigated the influence of varying Agt gene expression on the ovulatory capacity and early embryonic development in mice.

Design: Observational study of genetically altered mice and their response to a superovulation protocol.

Setting: Academic research institution.

Animal(s): Mice with varying copy numbers of Agt (one copy: N = 48; two copies: N = 51; three copies: N = 20; four copies: N = 24).

Intervention(s): Superovulation protocol, oocyte culture.

Main Outcome Measure(s): Number of oocytes harvested, early embryonic development of zygotes, evaluation of ovarian histology, serum estradiol measurements.

Result(s): The mean number of oocytes harvested was greatest in wild-type mice (two copies of Agt, 39.9 ± 14) with a reduction of ovulatory capacity in mice overexpressing Agt (three copies [34.8 ± 11.7] and four copies [31.2 ± 12.4], P = .026). Mice with one copy of Agt showed a slight decrease of ovulatory capacity compared to wild-type mice (35.8 ± 15.2, P = .29). Ovarian histology, serum estradiol levels, and early embryonic development were independent of the Agt genotype.

Conclusion(s): Overexpression of Agt was associated with reduced ovulatory capacity, but with none of the other parameters that were evaluated. These findings support an important role of the ovarian renin-angiotensin system in the process of follicular rupture.     

血管紧张素原T174M基因多态性与原发性高血压的关系

目的研究血管紧张素原T174M基因多态性与原发性高血压的关系。方法采用聚合酶链反应、限制性内切酶酶解(PCR-RFLP)及电泳分型的方法对四川泸州及其附近地区140例原发性高血压患者和40例血压正常者血管紧张素原的T174M基因多态性进行检测。结果高血压组与正常对照组比较,基因型频率分布差异无显著性,高血压组TT型、MT型和MM型分别为63.6%、33.6%、2.8%,对照组分别为72.5%、27.5%、0%;等位基因频率两组不同,高血压组M等位基因频率为19.6%,对照组为13.8%。高血压组T等位基因频率为80.4%,对照组为86.3%。结论血管紧张素原T174M基因多态性可能与四川川南地区人群原发性高血压有关。