Expression of Angiotensin Ⅱ Receptors in Aldosterone-producing Adenoma of the Adrenal Gland and Their Clinical Significance

The expression of angiotensin Ⅱ type 1 receptor (AT1R) and angiotensin Ⅱ type 2 receptor (AT2R) in aldosterone-producing adenoma (APA) of the adrenal gland was detected, and their relationship with clinical indexes of APA was analyzed. The mRNA expression of AT1R and AT2R in 50 cases of APA and tissues adjacent to tumors and 12 cases of normal adrenal tissues was detected by using reverse transcriptase polymerase chain reaction (RT-PCR). The expression of AT1R and AT2R proteins in paraffin-embedded slices of tissue was detected by immunohistochemistry. The expression of AT1R in adenoma, tissues adjacent to tumor, and normal tissues of the adrenal gland showed no significant differences. The expression of AT2R in APA tissue was lower than that in normal adrenal gland tissues (P<0.05). Correlation analysis of the mRNA expression level of AT2R and clinical data from patients demonstrated that AT2R expression was negatively related to plasma aldosterone concentration (PAC) (r=-0.467, P<0.05), but positively related with plasma renin activity (PRA) (r=0.604, P<0.05). It is concluded that down-regulation of the AT2R expression is possibly related with the tumorigenesis of APA.

A Quantitative Study on Vascular Angiotensin Ⅱ Receptors in Rats with Portal Hypertension

Angiotension-Ⅱ(A-Ⅱ) receptor maximal binding capacity (Bmax) and dissociation constants (Kd) of different blood vessels in rats with prehepatic portal hypertension were studied by radioligand binding analysis. The results showed that the A-Ⅱreceptor Bmax. in the thoracic aorta, superior mesenteric artery and portal vein of portal hypertensive animals (113. 7±19. 4 fmol/mg protein, 206.9 ±39. 3 fmol/mg protein and 31. 5±9. 2 fmol/mg protein respectively ) was all significantly lower than that of controls (146. 8±24. 5 fmol/mg protein, 297. 2±44. 7 fmol/mg protein and 53. 4±12.1 fmol/mg protein respectively, P＜0. 01).The A-Ⅱ receptor Kd in the superior mesenteric artery was markedly increased in portal hypertensive animals (1. 03±0.11 nmol/L) compared with that in controls (0. 88±0. 08 nmol/L, P＜0. 05). In the thoracic aorta and portal vein, the A-Ⅱ receptor Kd in portal hypertensive animals was slightly higher than that in controls, but no significant difference was observed between the two groups. The results suggested that the vascular hyporesponsiveness to A-Ⅱ in portal hypertension was caused partially by a reduction in number and a decrease in affinity of vascular A- Ⅱ receptors, and these changes might possibly lead to the formation of hyperdynamic circulation.

Role of angiotensin Ⅱ and angiotensin Ⅱ receptors in vascular smooth muscle cell migration in vitro

Objective To determine the biotic effects of angiotensin Ⅱ (Ang Ⅱ) on the migration of rat smooth muscle cells (VSMCs) and investigate the mechanisms involved in the development of vascular injury Methods VSMCs isolated from aortic media of Wistar rats and cultured by the modified explant method were adopted In the presence and absence of Ang Ⅱ, the expression of Ang Ⅱ receptor (ATR) and reorganization of the actin cytoskeleton and focal adhesion of VSMCs were studied by an immunocytochemistry technique and fluorocytochemistry technique Migration assays were performed with a modified Boyden's chamber The effects of AT 1R antagonist (CV 11974), AT 2R antagonist (PD123319) on the aforementioned target were studied Results VSMCs migration was stimulated by adding Ang Ⅱ The dynamic reorganization of actin cytoskeleton and focal adhesions may be an important mechanism by which Ang Ⅱ facilitates VSMCs motility The expression of AT 1R in VSMCs could be upregulated initially after treatment with Ang Ⅱ, then decreased gradually The expression of AT 1R was downregulated by AT 1R antagonists The effect of Ang Ⅱ on VSMCs migration was mediated by AT 1R, while AT 2R had no significant effect Conclusions The dynamic reorganization of focal adhesions and the actin cytoskeleton is required for Ang Ⅱ induced VSMCs migration This effect is mediated by AT 1R

Construction of shRNA Targeted to the Rat Angiotensin Ⅱ Type 1 Receptors and Its RNAi in Cytoplasma

The expression vector of shRNA targeted to the rat angiotensin Ⅱ receptor gene was constructed and the efficacy of siRNAs to modulate the expression of target gene in the in vitro cultured mammalian cells was investigated for antihypertensive therapy in spontaneous hypertensive rat （SHR） at post-transcriptional level. The sense and antisense RNA oligonucleotides strands targeting angiotensin Ⅱ receptor mRNA were synthesized individually according to the sequence of the rat angiotensin Ⅱ receptor. For preparation of duplexes, sense- and antisense-stranded oligonucleotides were mixed and annealed, and the annealed duplexes were cloned into the pGenesil-1 vector. The rat glioma cells were transfected with constructed pGenesil-1-shRNA plasmid and scrambled plasmid. The cultured cells were collected at different phases. RT-PCR and Western blot were performed. The AT1 mRNA and protein levels behaved ultimately same. Compared to control after 48 h, AT1 mRNA levels were decreased to 35.5%±3.0 %, and the levels reached their lowest point after 72 h （20.7% ±4 % of control）. At 24 and 48 h, AT1 protein was reduced to 46.9%±4.2% and 36.98%±3.7% respectively compared to control and a maximum reduction was observed after 72 h of incubation （28.1%± 4% compared to controls）. Plasmid-based shRNA expression systems targeted against the rat angiotensin Ⅱ receptor gene were generated successfully. The shRNAs with a 22-nt stem and a short loop were cleaved into small interfering dsRNA （siRNA） by the Dicer. The in vitro transcribed siRNA enables the effective silencing of gene expression to the target mRNA and leads to effective inhibition of translation of proteins and will be lay the foundation of application of gene silencing technology to hypertensive rats.

Effect of angiotensin Ⅱ type 1 receptor blocker and angiotensin converting enzyme inhibitor on the intraocular growth factors and their receptors in streptozotocin-induced diabetic rats

AIM： To investigate the effect of angiotensin II type 1 receptor blocker （ARB） and angiotensin converting enzyme inhibitor （ACEI） on intraocular growth factors and their receptors in streptozotocin-induced diabetic rats. METHODS： Forty Sprague-Dawley rats were divided into 4 groups： control, diabetes mellitus （DM）, candesartan- treated DM, and enalapril-treated DM （each group, n---10）. After the induction of DM by streptozotocin, candesartan [ARB, 5 mg/（kg · d）] and enalapril [ACEI, 10 mg/（kg · d）] were administered to rats orally for 4Wko Vascular endothelial growth factor （VEGF） and angiotensin II （Ang II） concentrations in the vitreous were measured using enzyme-linked immunosorbent assays, and VEGF receptor 2 and angiotensin II type 1 receptor （ATIR） levels were assessed at week 4 by Western blotting. RESULTS： Vitreous Ang II levels were significantly higher in the DM group and candesartan-treated DM group than in the control （P=0.04 and 0.005, respectively）. Vitreous ATIR increased significantly in DM compared to the other three groups （P〈0.007）. Candesartan-treated DM rats showed higher vitreal ATIR concentration than the enalapril-treated DM group and control （P〈0.001 and P=0.005, respectively）. No difference in vitreous Ang II and ATIR concentration was found between the enalapril- treated DM group and control. VEGF and its receptor were below the minimum detection limit in all 4 groups. CONCLUSION： Increased Ang II and ATIR in the hyperglycemic state indicate activated the intraocular renin-angiotensin system, which is inhibited more effectively by systemic ACEI than systemic ARB.

Inhibition of angiotensin Ⅱ and blockade of endothelin receptors reduce arterial calcification in rats

Objective To examine whether the two vascular paracrine/autocrine factors,angiotensin Ⅱ(Ang Ⅱ)and endothelin,participate in the pathogenesis of arterial calcification.Methods Nicotine and vitamin D_3 treated rats were studied.Vascular calcification was confirmed by using Von Kossa staining,measurement of calcium content, ^(45)Ca^(2+)uptake assay and alkaline phosphatase(ALP)activity.The plasma and vascular Ang Ⅱ and endothelin levels were measured by using radioimmunoassay.Angiotensinngen and endothehn mRNA levels were determined by RT- PCR.Results The arterial calcium content,^(45)Ca^(2+)uptake and ALP activity were increased in calcification groups compared with control(P<0.01).Administration of the angiotensin receptor antagonist losartan,the endothelin receptor antagonist bosentan,and the angiotensin-converting enzyme inhibitor captopril reduced significantly the arterial calcium content,^(45)Ca^(2+)uptake and ALP activity.In addition,the plasma and aortic Ang Ⅱ and endothelin contents,and vascular angiotensinngen and endothelin mRNA expression were significantly up-regulated(P<0.05). Conclusions These findings suggest that functional renin-angiotensin system and endothelin pathway are involved in vascular calcification,and that activation of these systems could potentiate pathogenesis of arterial calcification.(J Geriatr Cardiol 2004;1(2):108-113.)

Activation of angiotensin Ⅱ type 1 receptors in the median preoptic nucleus induces a diuretic and natriuretic response in rats

Objective： To investigate the effect of activation of angiotensin Ⅱ（AngⅡ） type 1 （AT1） receptors in the median preoptic nucleus （MnPO） of rats on renal sodium excretion. Methods： After anesthesia, the rats were injected into the MnPO via an implanted cannula. Urine samples were collected via a bladder cannula, and the urine sodium concentration was assayed with flame spectrophotometry. The serum level of endogenous digitalis-like factor （EDLF） and Na^＋,K^＋-ATPase activity in the renal cortex tissue were assayed respectively with a radioimmunoassay and with an ammonium molybdophosphate-based kit. Results： Both the urinary volume and the sodium excretion peaked 60 min after AngⅡ was administered into the MnPO. The responses were accompanied by an increase in serum EDLF and a decrease in Na^＋,K^＋-ATPase activity in the renal cortex. The responses of diuresis and natriuresis, as well as an increase in serum EDLF and a decrease in Na^＋,K^＋-ATPase activity in the renal cortex induced by MnPO adminstration with AngⅡ were inhibited by pior treatment with the AngⅡ receptor blocking agent losartan into the MnPO. Conclusion： These results suggest that activation of AT1 receptors in the MnPO of rat induces diuretic and natriuretic responses. The responses are associated with an increase release of EDLF and with the inhibition of Na^＋,K^＋-ATPase activity in renal cortex tissue.

Effect of rosuvastatin on expression of angiotensin Ⅱ receptors in rat aortic endothelium after balloon injury

Background It＇s established that Angiotensin Ⅱ and its receptors are involved in intimal hyperplasia after balloon injury and stent restenosis. Recent evidence also suggests that statins have some anti-intimal hyperplasia effects. In this study, the effect of Rosuvastatin on expression of angiotensin Ⅱ receptors in rat aortic endothelium after balloon injury is therefore investigated. Methods All 52 Wistar Kyoto rats were established to aorta injury models by 2F balloon catheter, then were randomly divided into sham operation group, aorta injury group and Rosuvastatin-treatment group. After 14 days, the aortic specimens of the animals were harvested and performed immunohistochemistry and determination of molecular biology. Results The results showed that （i） The 14 days-balloon injury induced obvious intima thickening （P 〈 0.01）, however, the phenomenon was reduced by 14 daystreatment with Rosuvastatin （P 〈 0.01）. （ii） The expressions of angiotention Ⅱ type Ⅰ （AT1） and type Ⅱ （AT2） receptor mRNA and protein were markedly up-regulated by the balloon injury （P 〈 0.01）, after 14 days-treatment with Rosuvastatin, the expression of AT1 receptor mRNA and its protein was decreased （P 〈 0.01）, but the expression of AT2 receptor mRNA and its protein was further increased （P 〈 0.05）. Conclusion In this study, we observed that the balloon injury induced-intima thickening was reduced by Rosuvastatin in rats, which might be linked with the regulation of expression of angiotensin Ⅱ receptors.

N-methyl-D-aspartate receptors mediate diphosphorylation of extracellular signal-regulated kinases through Src family tyrosine kinases and Ca^2＋/calmodulin-dependent protein kinase Ⅱ in rat hippocampus after cerebral ischemia

Objective： Extracellular signal-regulated kinases （ERKs） can be activated by calcium signals. In this study, we investigated whether calcium-dependent kinases were involved in ERKs cascade activation after global cerebral ischemia. Methods Cerebral ischemia was induced by four-vessel occlusion, and the calcium-dependent proteins were detected by immunoblot. Results Lethal-simulated ischemia significantly resulted in ERKs activation in N-methyl-D-aspartate （NMDA） receptor-dependent manner, accompanying with differential upregulation of Src kinase and Ca^2＋/calmodulin-dependent protein kinase Ⅱ （CaMKⅡ） activities. With the inhibition of Src family tyrosine kinases or CaMKⅡ by administration of PP2 or KN62, the phosphorylation of ERKs was impaired dramatically during post-ischemia recovery. However, ischemic challenge also repressed ERKs activity when Src kinase was excessively activated. Conclusions Src family tyrosine kinases and CaMKⅡ might be involved in the activation of ERKs mediated by NMDA receptor in response to acute ischemic stimuli in vivo, but the intense activation of Src kinase resulted from ischemia may play a reverse role in the ERKs cascade.

血清α1-抗胰蛋白酶、血管紧张素-Ⅱ与获得性免疫缺陷综合征患者预后的关系

目的探讨血清α1-抗胰蛋白酶(α1-AT)、血管紧张素-Ⅱ(Ang-Ⅱ)与获得性免疫缺陷综合征(AIDS)患者预后的关系。方法将该院2019年5月至2022年5月收治的97例首诊AIDS患者纳入研究作为研究组,另选取同期于该院进行体检的健康者97例作为对照组。根据病历收集患者临床资料。对纳入研究者进行α1-AT、Ang-Ⅱ水平检测,并进行分组比较。对纳入研究的AIDS患者进行为期1年的随访,观察患者预后情况,并比较不同预后患者的α1-AT、Ang-Ⅱ水平。采用单因素及多因素Logistic回归分析影响AIDS患者预后的因素。用受试者工作特征(ROC)曲线分析α1-AT、Ang-Ⅱ水平对患者预后的预测效能。结果研究组血清α1-AT和Ang-Ⅱ水平高于对照组(P<0.05)。AIDS患者1年内的预后不良发生率为23.71%(23/97)。预后不良患者血清α1-AT和Ang-Ⅱ水平高于预后良好患者(P<0.05)。单因素分析显示,预后不良患者C反应蛋白(CRP)水平、淋巴细胞计数水平、合并淋巴瘤者所占比例均高于预后良好患者,清蛋白(ALB)水平低于预后良好患者(P<0.05)。多因素Logistic回归分析显示,合并淋巴瘤(OR=2.087)、高α1-AT水平(OR=2.611)、高Ang-Ⅱ水平(OR=2.138)是影响患者预后的独立危险因素(P<0.05)。ROC曲线分析显示,α1-AT预测AIDS患者预后的曲线下面积(AUC)为0.778,Ang-Ⅱ预测的AUC为0.798,α1-AT联合Ang-Ⅱ预测的AUC为0.918。结论α1-AT和Ang-Ⅱ在AIDS患者血清中水平异常升高,而且与患者预后有关,是影响患者预后的独立危险因素。α1-AT和Ang-Ⅱ联合检测可有效预测患者预后。

Effects of angiotensin Ⅱ receptor antagonist, Losartan on the apoptosis, proliferation and migration of the human pancreatic stellate cells

AIM： To investigate the effects of AT, （Type 1 angiotensin Ⅱ receptor） antagonist （Losartan） on the apoptosis, proliferation and migration of the human pancreatic stellate cells （hPSCs）. METHODS： hPSCs were isolated from pancreatic sample of patients with pancreatic carcinoma using radioimmunoassay （RIA） technique to detect the concentration of AngⅡ in culture media and cell homogenate. Immunocytochemistry （ICC） and in situ hybridization （ISH） methods were utilized to test AT1 expression in hPSCs. Effects of Losartan on hPSCs proliferation, apoptosis and migration were investigated using BrdU incorporation, TUNEL, flow cytometry （FCM）, and phase-contrast microscope separately when cells treated with Losartan. Immunofluorescence and Western blot were applied to quantify the expression of type Ⅰ collagen in hPSCs. RESULTS： There exists AT1 expression in hPSCs, while no AngⅡ was detected in culture media and cell homogenate. Losartan induces cell apoptosis in a doseand time-dependent manner （apparently at 10^-5 mol/L）, no pro-proliferative effect was observed in the same condition. Corresponding dosage of Losartan can also alleviate the motion capability and type Ⅰ collagen content of hPSCs compared with AngⅡ treatment and non-treatment control groups. CONCLUSION： These findings suggest that paracrine not autocrine functions of AngⅡ may have effects on hPSCs, which was mediated by AT1 expressed on cells, while Losartan may exert anti-fibrotic effects by inhibiting hPSCs motion and partly by inducing apoptosis.

Association of Polymorphisms in Angiotensin-converting Enzyme and Type 1 Angiotensin Ⅱ Receptor Genes with Coronary Heart Disease and the Severity of Coronary Artery Stenosis

To explore the relation of angiotensin-converting enzyme （ACE） and angiotensin Ⅱ type 1 receptor （AT1R） gene polymorphism with coronary heart disease （CHD） and the severity of coronary artery stenosis, 130 CHD patients who underwent coronary angiography were examined for the number of affected coronary vessels （≥75% stenosis） and coronary Jeopardy score. The insertion/deletion of ACE gene polymorphism and AT1R gene polymorphism （an A→C transversion at nucleotide position 1166） were detected by using polymerase chain reaction （PCR） and restriction fragment length polymorphism （RFLP） in CHD patients and 90 healthy serving as controls. The resuits showed that DD genotype and of ACE were more frequent in CHD patients than that in control group （38.5% vs 14.4%, P〈0.001）. The frequency of the ATIR A/C genotypes did not differ between the patients and the controls （10% vs 13.1%, P〉0.05）. The relative risk associated with the ACE-DD was increased by AT1R-AC genotype. Neither the number of affected coronary vessels nor the coronary score differed among the ACE I/D genotypes （P〉0.05）. But the number of affected coronary vessels and the coronary score were significantly greater in the patients with the AT1R-AC genotype than in those with the AA genotype （P〈0.05）. In conclusion, DD genotype may be risk factor for CHD and MI in Chinese people, and is not responsible for the development of the coronary artery stenosis. The AT1R-C allele may increase the relative risk associated with the ACE-DD genotype, and may be involved in the development of the stenosis of coronary artery.

Effect of nuclear factor-κB and angiotensin Ⅱ receptor type 1 on the pathogenesis of rat non-alcoholic fatty liver disease

AIM: To investigate the roles of nuclear factor(NF)-κB and angiotensin Ⅱ receptor type 1(AT1R) in the pathogenesis of non-alcoholic fatty liver disease(NAFLD).METHODS: Forty-two healthy adult male SpragueDawley rats were randomly divided into three groups:the control group(normal diet), the model group,and the intervention group(10 wk of a high-fat diet feeding, followed by an intraperitoneal injection of PDTC); 6 rats in each group were sacrificed at 6, 10,and 14 wk. After sacrifice, liver tissue was taken,paraffin sections of liver tissue specimens were prepared, hematoxylin and eosin(HE) staining was performed, and pathological changes in liver tissue(i.e., liver fibrosis) were observed by light microscopy.NF-κB expression in liver tissue was detected by immunohistochemistry, and the expression of AT1 R in the liver tissue was detected by reverse transcriptionpolymerase chain reaction(RT-PCR). The data are expressed as mean ± SD. A two-sample t test was used to compare the control group and the model group at different time points, paired t tests were used to compare the differences between the intervention group and the model group, and analysis of variance was used to compare the model group with the control group. Homogeneity of variance was analyzed with single factor analysis of variance. H variance analysis was used to compare the variance. P < 0.05 wasconsidered statistically significant.RESULTS: The NAFLD model was successful after 6wk and 10 wk. Liver fibrosis was found in four rats in the model group, but in only one rat in the intervention group at 14 wk. Liver steatosis, inflammation, and fibrosis were gradually increased throughout the model. In the intervention group, the body mass,rat liver index, serum lipid, and transaminase levels were not increased compared to the model group.In the model group, the degree of liver steatosis was increased at 6, 10, and 14 wk, and was significantly higher than in the control group(P < 0.01). In the model group, different degrees of liver cell necrosis were visible and small leaves, punctated inflammation,focal necrosis, and obvious ballooning degeneration were observed. Partial necrosis and confluent necrosis were observed. In the model group, liver inflammatory activity scores at 6, 10, and 14 wk were higher than in the control group(P < 0.01). Active inflammation in liver tissue in the intervention group was lower than in the model group(P < 0.05). HE staining showed liver fibrosis only at 14 wk in 4/6 rats in the model group and in 1/6 rats in the intervention group. NF-κB positive cells were stained yellow or ensemble yellow,and NF-κB was localized in the cytoplasm and/or nucleus. The model group showed NF-κB activation at6, 10, and 14 wk in liver cells; at the same time points,there were statistically significant differences in the control group(P < 0.01). Over time, NF-κB expression increased; this was statistically lower(P < 0.05) at14 weeks in the intervention group compared to the model group, but significantly increased(P < 0.05)compared with the control group; RT-PCR showed that AT1 R mRNA expression increased gradually in the model group; at 14 wk, the expression was significantly different compared with expression at 10 weeks as well as at 6 weeks(P < 0.05). In the model group, AT1 R mRNA expression was significantly higher than at the same time point in the control group(P <0.01).CONCLUSION: With increasing severity of NAFLD,NF-κB activity is enhanced, and the inhibition of NF-κB activity may reduce AT1 R mRNA expression in NAFLD.

The expression of the products of IGF-Ⅱ,IGF-Ⅱ receptors and CSF-Ⅰ receptors in human primary hepatocellular carcinoma and juxtacancerous liver tissue

The expression of the products of IGF-Ⅱ,IGF-Ⅱ receptors(IGF-Ⅱ-R)and CSF-Ⅰ re-ceptors(CSF-Ⅰ-R)was observed in 17 cases of human primary hepatocellular carcinoma(PHC)and the juxtacancerous liver tissue with immunohistochemistry(ABC),Western blot and North-ern blot technique,It was found that the expression of IGF-Ⅱ,IGF-Ⅱ-R and CSF-Ⅰ-R was signif-icantly higher in PHC than in normal liver tissue and the expression of IGF-Ⅱ and IGF-Ⅱ-R wasremarkably higher in the juxtacancerous liver tissue from PHC patients than in PHC proper.Itwas noteworthy that the expression of IGF-Ⅱ in both the cancer proper and the juxtacancerousliver tissue was characterized by its fetal type.Besides,the expression of CSF-Ⅰ-R was signifi-cantly higher in PHC than in the juxtacancerous liver tissue.It is believed that the abnormal ex-pression of IGF-Ⅱ,IGF-Ⅱ-R and CSF-I-R in PHC and the juxtacaneerous liver tissue might berelated to the autocrine mechanism of human PHC.

Association of Polymorphisms in Angiotensin Ⅱ Receptor Genes with Aldosterone-producing Adenoma

This study examined the association of polymorphisms in angiotensinⅡreceptor genes（AT1R and AT2R） with the risk for aldosterone-producing adenoma（APA） in a Chinese Han population.Four polymorphisms including rs5182（573T/C） in exon 4,rs5186（1166A/C） in 3＇-untranslated region（3＇-UTR） in AT1R gene and rs5194（2274G/A） in 3＇-UTR,rs1403543（1675G/A） in intron 1 in AT2R gene were detected in 148 APA patients and 192 normal subjects（serving as control） by using a MGB-Taqman probe.The distribution of genotypes of each locus was in accordance with Hardy-Weinberg Equilibrium（HWE） in the APA and control groups（P0.05）.The allele A frequency at rs5194 was significantly higher in the APA group（0.49） than in the control group（0.35）（χ2=12.08,P=0.001）.Subjects with homozygotic genotype AA and heterozygotic genotype GA were at an increased risk for APA as compared to those with GG genotype（OR=2.66,95% CI=1.45-4.87;OR=1.67,95% CI=1.02-2.74）.Furthermore,rs5194 single-nucleotide polymorphism（SNP） at AT2R gene was significantly associated with APA in additive（OR=1.64,95% CI=1.21-2.20,P=0.001）,dominant（OR=1.94,95% CI=1.23-3.06,P=0.003）,and recessive model（OR=2.01,95% CI=1.17-3.45,P=0.01）.It was concluded that rs5194 polymorphism at AT2R gene was associated with the risk for APA,which may constitute a genetic marker of APA.

Effects of angiotensin-converting enzyme inhibitor and angiotensin Ⅱ receptor blocker on one-year outcomes of patients with atrial fibrillation: insights from a multicenter registry study in China

Objective To evaluate the effect of angiotensin-converting enzyme inhibitor(ACEI)/angiotensin Ⅱ receptor blocker(ARB)therapy on the prognosis of patients with atrial fibrillation(AF).Methods A total of 1,991 AF patients from the AF registry were divided into two groups according to whether they were treated with ACEI/ARB at recruitment.Baseline characteristics were carefully collected and analyzed.Logistic regression was utilized to identify the predictors of ACEI/ARB therapy.The primary endpoint was all-cause mortality,while the secondary endpoints included cardiovascular mortality,stroke and major adverse events(MAEs)during the one-year follow-up period.Univariable and multivariable Cox regression were performed to identify the association between ACEI/ARB therapy and the one-year outcomes.Results In total,759 AF patients(38.1%)were treated with ACEI/ARB.Compared with AF patients without ACEI/ARB therapy,patients treated with ACEI/ARB tended to be older and had a higher rate of permanent AF,hypertension,diabetes mellitus,heart failure(HF),left ventricular ejection fraction(LVEF)<40%,coronary artery disease(CAD),prior myocardial infarction(MI),left ventricular hypertrophy,tobacco use and concomitant medications(all P<0.05).Hypertension,HF,LVEF<40%,CAD,prior MI and tobacco use were determined to be predictors of ACEI/ARB treatment.Multivariable analysis showed that ACEI/ARB therapy was associated with a significantly lower risk of one-year all-cause mortality[hazard ratio(HR)(95%CI):0.682(0.527-0.882),P=0.003],cardiovascular mortality[HR(95%CI):0.713(0.514-0.988),P=0.042]and MAEs[HR(95%CI):0.698(0.568-0.859),P=0.001].The association between ACEI/ARB therapy and reduced mortality was consistent in the subgroup analysis.Conclusions In patients with AF,ACEI/ARB was related to significantly reduced one-year all-cause mortality,cardiovascular mortality and MAEs despite the high burden of cardiovascular comorbidities.

DNA methylation of angiotensin Ⅱ receptor gene in nonalcoholic steatohepatitis-related liver fibrosis

AIM To clarify whether Agtr1 a methylation is involved in the development of nonalcoholic steatohepatitis(NASH)-related liver fibrosis in adult rats.METHODS A choline-deficient amino acid(CDAA) diet model was employed for methylation analysis of NASH-related liver fibrosis.Agtr1 a methylation levels were measured in the livers of CDAA- and control choline-sufficient amino acid(CSAA)-fed rats for 8 and 12 wk using quantitative methylation-specific PCR.Hepatic stellate cells(HSCs) were isolated by collagenase digestion of the liver,followed by centrifugation of the crude cell suspension through a density gradient.Agtr1 a methylation and its gene expression were also analyzed during the activation of HSCs.RESULTS The mean levels of Agtr1 a methylation in the livers of CDAA-fed rats(11.5% and 18.6% at 8 and 12 wk,respectively) tended to be higher(P = 0.06 and 0.09,respectively) than those in the livers of CSAA-fed rats(2.1% and 5.3% at 8 and 12 wk,respectively).Agtr1 a was not methylated at all in quiescent HSCs,but was clearly methylated in activated HSCs(13.8%,P < 0.01).Interestingly,although Agtr1 a was hypermethylated,the Agtr1 a m RNA level increased up to 2.2-fold(P < 0.05) in activated HSCs compared with that in quiescent HSCs,suggesting that Agtr1 a methylation did not silence its expression but instead had the potential to upregulate its expression.These findings indicate that Agtr1 a methylation and its upregulation of gene expression are associated with the development of NASH-related liver fibrosis.CONCLUSION This is the first study to show that DNA methylation is potential y involved in the regulation of a renin-angiotensin system-related gene expression during liver fibrosis.

Origin and genomic characteristics of SARS-CoV-2 and its interaction with angiotensin converting enzyme type 2 receptors, focusing on the gastrointestinal tract

The emergence of coronavirus disease-2019 induced by a newly identified bcoronavirus, namely severe acute respiratory syndrome coronavirus 2(SARSCoV-2) has constituted a public health emergency. Even though it was considered a zoonotic disease, the virus has also spread among humans via respiratory secretions. The expression and distribution of angiotensin converting enzyme type 2(ACE2) in various human organs might also show other possible infection routes. High ACE2 ribonucleic acid expression has been identified in the gastrointestinal tract(GI) indicating its importance as a possible infection pathway of SARS-CoV-2. ACE2 induces viral entry into the host and most importantly has been found to be associated with the function of the gut. Its deficiency has been implicated in several pathologies such as colorectal inflammation. The renin-angiotensin system(RAS) is an essential regulatory cascade operating both at a local tissue level and at the systemic or circulatory level. The RAS may be important in the pathogenesis of chronic liver disease and is associated with the up-regulation of ACE2. Thus, the aim of this review is firstly, the analysis of some important general and genome characteristics of SARS-CoV-2 and secondly, and most importantly, to focus on the utility of ACE2 receptors in both SARS-CoV-2 replication and pathogenesis, especially in the GI tract.

Effect of Microinfusion of Angiotensin Ⅱ into the RVLM in Rats on the Baroreceptor Reflex Sensitivity

Objective: The present study was designed to investigate the effect of microinfusion angiotensin Ⅱ(Ang Ⅱ),Ang Ⅱ type 1(AT_1)receptor antagonist losartan into the rostral ventrolateral medulla(RVLM)on the baroreceptor reflex sensitivity(BRS)in urethane-anesthetized rats. Methods: Reflex changes in heart rate(HR)were elicited by bolus intravenous injection of phenylephrine before and during RVLM microinfusion of saline(0.5 μl/h),Ang Ⅱ (1.5 nmol/h),losartan(250 nmol/h),and Ang Ⅱ(1.5 nmol/h)pretreated with microinjection of losartan (50 nmol/0.51 μl)into the RVLM.The average ratio between changes in HR in beats per minute(beats·min -1)and changes in mean arterial pressure [MAP,mmHg(1 mmHg=0.133 kPa)] was used as an index of BRS. Results: Ang Ⅱ resulted in a significant decrease in the BRS for reflex bradycardia compared with control(-2.1±0.1 vs-3.9±0.4 beats·min -1·mmHg -1).Microinfusion of losartan had no significant effect on BRS for reflex bradycardia.The effect of Ang Ⅱ was almost completely abolished by pretreatment with microinjection of losartan. Conclusion:These results showed that the exogenous Ang Ⅱ in the RVLM produces inhibitory modulation of BRS,which is mediated by AT_1 receptor.However,AT_1 receptor in the RVLM is not involved in the tonic control of BRS.

血管紧张素Ⅱ对大鼠骨髓间充质干细胞棕色脂肪变的抑制作用

背景:骨髓间充质干细胞是脂肪细胞的来源之一,且表达所有肾素血管紧张素系统成分,但血清血管紧张素Ⅱ对骨髓间充质干细胞向棕色脂肪组织分化的影响尚不清楚。目的:观察血管紧张素Ⅱ对骨髓间充质干细胞向棕色脂肪细胞分化的影响,并探究血管紧张素1a型受体敲除对血管紧张素Ⅱ影响骨髓间充质干细胞向棕色脂肪细胞分化的作用及可能机制。方法:分离培养野生型SD大鼠及血管紧张素1a型受体敲除SD大鼠的骨髓间充质干细胞,将其培养至第3代,随机分为4组:野生组,基因敲除组,野生+血管紧张素Ⅱ组,基因敲除+血管紧张素Ⅱ组,在棕色脂肪诱导分化培养基中诱导分化14 d,后2组在每次更换分化培养基的同时加入100 nmol/L血管紧张素Ⅱ进行干预。采用Western blot、qRT-PCR、免疫荧光等方法检测棕色脂肪诱导分化、脂肪分解、β氧化和线粒体生物发生等相关标记物的表达。结果与结论:血管紧张素Ⅱ可抑制骨髓间充质干细胞向棕色脂肪细胞分化,敲除血管紧张素1a型受体基因能够通过促进脂肪分解、增强脂肪酸β氧化、促进线粒体生物发生、增强线粒体功能来改善血管紧张素Ⅱ对骨髓间充质干细胞向棕色脂肪细胞分化的抑制作用。这些发现为肥胖治疗提供了新的研究方向和潜在治疗靶点,揭示了肾素血管紧张素系统在脂肪代谢中的重要作用及其作为治疗目标的潜力。