海蟾蜍毒素与盐敏感性高血压研究进展

盐敏感性高血压是一种特殊类型的高血压,因其特殊的发病机制和临床特征,近年来受到越来越多的关注;海蟾蜍毒素是一种内源性洋地黄类物质,是人类和动物体内广泛分布的Na+/K+-ATP酶的单一性配体;海蟾蜍毒素通过阻断钠钾ATP酶及多种信号途径介导水钠潴留、血压升高、心肌和血管纤维化等多种病理机制,在盐敏感性高血压的发生发展中发挥重要作用,本综述就海蟾蜍毒素与盐敏感性高血压的相关关系最新研究进展情况作综合介绍。     

感觉神经损伤性盐敏感性高血压大鼠左心室肥厚与血压的关系

目的研究感觉神经损伤性盐敏感性高血压大鼠左心室肥厚与血压的关系。方法建立感觉神经损伤性盐敏感性高血压大鼠模型,计算左心室相对重量,观察左心室组织病理学形态特点。结果感觉神经损伤性盐敏感性高血压大鼠CAP-HS组收缩压明显升高,左心室明显增重,心肌细胞肥大,肌纤维排列紊乱,心肌间质纤维化,其左心室重量指数明显升高（P〈0.01）;CON-HS组大鼠左心室重量指数也有升高（P〈0.05）。结论感觉神经损伤性盐敏感性高血压大鼠左心室增重,心肌组织病理学改变与血压升高和摄入高盐有关。     

果糖诱导盐敏感性高血压的肾脏机制(英文)

从过去一个世纪以来,果糖的进食量急剧增加,并且与糖尿病、肥胖、肾衰、高血压等的发生密切相关。目前越来越多的证据证明过量的果糖饮食会引起盐敏感性高血压,其发生机制十分复杂,但是肾脏可能在其中扮演着重要的角色。本文主要阐述了果糖诱导盐敏感性高血压的肾相关机制,包括肾素原受体依赖的肾内肾素-血管紧张素系统的活化,肾内Na~+转运体钠氢交换子3 (sodium/hydrogen exchanger 3, NHE3)和Na-K-2Cl共转运体(Na/K/2Cl cotransporter, NKCC2)的活化,肾内尿酸产生的增加,肾内一氧化氮合成的降低,以及肾内活性氧产生的增加,并以此为理论依据提出潜在的治疗盐敏感性高血压的靶点或策略。     

盐敏感性高血压大鼠eNOS、iNOS表达与心肌细胞凋亡关系分析

目的探讨盐敏感性高血压形成和心肌细胞损害产生的机制。方法以辣椒辣索损伤Wistar大鼠感觉神经,饲喂高盐饲料,建立盐敏感性高血压大鼠模型。苏木素～伊红染色观察大鼠组织病理学改变;分光光度法检测心肌组织iNOS活性和NO含量;免疫组织化学方法检测心肌eNOS、iNOS蛋白表达;RT．PCR检测心肌eNOS、iNOSmRNA的表达。单细胞凝胶电泳检测心肌细胞凋亡。结果实验结束时各组比较体重无显著性差异（P〉0．05）。在第2、3、4周时,辣椒辣素高盐组鼠尾收缩压与对照组相比差异显著（P〈0．05）。辣椒辣素高盐组心肌细胞排列紊乱、细胞间隙明显增大,细胞核排列不整齐;心肌iNOS、NO水平升高（P〈0．05）;eNOS蛋白表达减少（P〈0．05）与eNOSmRNA表达减少（P〈0．01）;iNOS蛋白表达和iNOSmRNA表达显著增高（P〈0．01）;凋亡细胞数升高（P〈0．05）。结论eNOSmRNA和蛋白的低表达与感觉神经损伤性盐敏感性高血压大鼠形成相关。iNOSmRNA和蛋白的高表达及iNOS活性升高使心肌组织局部产生大量NO。NO可能使得感觉神经损伤性盐敏感性高血压大鼠心肌细胞凋亡增加,从而加重心肌的损伤。     

感觉神经损伤性盐敏感性高血压大鼠心、肾AT1R的表达

目的对感觉神经损伤性盐敏感性高血压大鼠的心肌、肾脏组织中的血管紧张素Ⅱ1型受体（AT1R）在mRNA和受体水平的表达进行检测,探讨AT1R与盐敏感性高血压的关系。方法用乳鼠皮下注射辣椒辣素法建立模型。哺乳期后,大鼠被随机分成4组：对照＋正常盐饮食组（CON-NS）;对照＋高盐饮食组（CON-HS）;辣椒辣素＋正常盐饮食组（CAP-NS）;辣椒辣素＋高盐饮食组（CAP-HS）。至7周龄（分组饲养后第4周）处死大鼠,免疫组织化学方法和反转录-聚合酶链式反应（RT-PCR）分别检测大鼠心肌和肾脏AT1R蛋白,以及AT1 R mRNA的表达。结果①Wistar大鼠在给予不同程度的感觉神经损伤和饲料干预后,各组大鼠尾部收缩压均有明显增加,最终CAP-HS组的尾收缩压显著高于其他三组（P〈0.01）。②免疫组织化学结果显示,CAP-HS组组织有显著的AT1R蛋白表达（P〈0.01）;CON-HS组肾脏、心肌组织中AT1R蛋白表达高于CON-NS组（P〈0.05）。③RT-PCR检测基因表达,与对照组CON-NS相比,实验组CAP-HS的AT1R mRNA表达显著升高（P〈0.01）;CON-HS组肾脏、心肌组织中AT1 R mRNA表达有显著性（P〈0.05）。结论感觉神经损伤性盐敏感性高血压大鼠心、肾AT1R表达升高,AT1R表达水平的差异可能与盐敏感性高血压的形成有关。     

Dahl盐敏感大鼠高血压形成的肾脏代谢机制

肾脏调控着机体的水盐代谢、血容量和血管阻力,是参与血压调节的主要靶器官.高盐饮食会诱发盐敏感个体水钠潴留以及持续性的内皮功能障碍,并促成血压升高.Dahl盐敏感(Dahl salt sensitive,Dahl-SS)大鼠作为研究盐敏感高血压的经典动物模型,具备血压的盐敏感性、高脂血症、胰岛素抵抗、肾功能衰竭、尿蛋白分...     

基于“咸入肾”理论探讨肠-肾轴与盐敏感性高血压的相关性

《素问·经脉别论》云：“生病起于过用”。人体疾病的产生在于体内阴阳失衡,风、火、痰、瘀之邪内生。因此,人体物质摄入之“度”是机体阴阳平衡与脏腑相和的重要前提。盐敏感性高血压很好地反映了高盐摄入与高血压显著相关,中医认为咸味入肾,胜血伤肝,助湿伤脾,使阳亢风动,痰湿中阻,导致风逆于上,气滞于中,水行不畅,进而引肝风上扰清窍,清阳滞于中州,导致血压升高。而肠-肾轴理论从肠道微生态角度说明了肠道菌群在调控血压中的重要作用。本文就肠-肾轴与盐敏感性高血压的关系进行探讨,以期从新的视角为高血压的早期防治提供干预方案。     

盐敏感性高血压大鼠纹蛋白水平变化对醛固酮及p38MAPK通路的影响

摘要 目的：探讨盐敏感性高血压大鼠纹蛋白水平变化对醛固酮及p38MAPK通路的影响。方法：通过向新生大鼠皮下注射辣椒素和高盐饮食构建盐敏感性高血压大鼠模型,分别使用醛固酮（ALDO）和醛固酮、依普利酮联合给药,实验分组为：1）正常对照组;2）模型组;3）假手术组;4）ALDO组;5）ALDO+依普利酮组。通过ELISA检测大鼠血浆中ALDO含量和外周血肾素含量,通过qPCR和WB检测大鼠心脏、肾脏、血管平滑肌中striatin和p38 MAPK的mRNA和蛋白的表达变化。结果：造模后在给药前大鼠血压有不同程度的升高,给药后ALDO组和ALDO+ Eplerenone组血压均有一定程度的下降;给药后ALDO+Eplerenone组大鼠血浆中ALDO和外周血中肾素含量升高;在肾脏与Control组和Model组相比,ALDO+Eplerenone组的striatin和p38 MAPK蛋白表达水平显著升高,p38 MAPK的 mRNA表达水平显著升高;在心脏中与Model组相比,ALDO+Eplerenone组的p38 MAPK蛋白表达水平显著升高;在主动脉中与Control组和Model组相比,ALDO+Eplerenone组的striatin和p38 MAPK蛋白表达水平显著降低。结论：纹蛋白水平的改变与盐敏感高血压具有相关性,其可通过调节ALDO/MR→p38MAPK相关通路影响盐敏感性高血压。     

感觉神经损伤性盐敏感性高血压大鼠心、肾ACE和ACE2的表达

目的研究肾素-血管紧张素系统（RAS）基因血管紧张素转换酶（ACE）和血管紧张素转换酶2（ACE2）在感觉神经损伤性盐敏感性高血压大鼠心肌和肾脏中的表达情况,探讨ACE、ACE2在盐敏感性高血压发生发展中的作用。方法用乳鼠皮下注射辣椒辣素法建立模型。哺乳期后,大鼠被随机分成4组：对照＋正常盐饮食组（CON-NS）、对照＋高盐饮食组（CON-HS）、辣椒辣素＋正常盐饮食组（CAP-NS）、辣椒辣素＋高盐饮食组（CAP-HS）。四组大鼠分别接受4周不同的处理。至7周龄（分组饲养后第4周）处死大鼠,免疫组化检测大鼠心肌和肾脏ACE和ACE2蛋白的表达,反转录-聚合酶链式反应（RT-PCR）检测大鼠心肌和肾脏ACE和ACE2mRNA的表达。结果①至7周龄（分组饲养后第4周）各组动物体重差异无显著性（P〉0.05）。②各组动物在分组时（0周）鼠尾收缩压差异无显著性（P=0.583）,至7周龄（分组饲养后第4周）,CAP-HS组鼠尾收缩压明显高于其它三组（P〈0.01）。③心肌和肾脏ACE蛋白表达均升高。心肌组织,CAP-HS组与CON-NS比较,P〈0.01,与CON-HS和CAP-NS比较,P〈0.05;肾脏组织,CAP-HS组与其它三组比较,P〈0.01。④心肌和肾脏ACE2蛋白表达均降低。心肌和肾脏组织,CAP-HS组与CON-NS和CAP-NS比较,P〈0.01,与CON-HS比较,P〈0.05。⑤心肌和肾脏ACE mRNA表达均升高。心肌组织,CAP-HS组与CON-NS比较,P〈0.01,与CON-HS和CAP-NS比较,P〈0.05;肾脏组织,CAP-HS组与其它三组比较,P〈0.01。⑥心肌和肾脏ACE2 mRNA表达均降低。心肌和肾脏组织,CAP-HS组与CON-NS和CAP-NS比较,P〈0.01,与CON-HS比较,P〈0.05。结论感觉神经损伤性盐敏感性高血压大鼠心、肾ACE表达升高的同时有ACE2表达的降低,ACE和ACE2表达水平的差异可能与盐敏感性高血压的形成有关。     

不同盐浓度对盐敏感性高血压肾脏纤维化及巨噬细胞浸润的影响

目的:探讨不同盐浓度对盐敏感高血压肾脏纤维化及及巨噬细胞浸润的影响。方法:将6周龄Dahl盐敏感大鼠随机分为正盐组(0.3%氯化钠)、4%氯化钠组、8%氯化钠组三组,每组15只,持续喂养8周。在8周时间点应用tail-cuff method方法监测鼠尾血压,Masson三原色法检测三组大鼠肾脏组织纤维化情况,免疫组化及Western blotting方法检测各组大鼠肾脏巨噬细胞浸润情况。结果:1)4%高盐组及8%高盐组大鼠8周时间点血压均较正盐组现在升高,8%高盐组大鼠血压较4%高盐组进一步升高。2)4%高盐组及8%高盐组大鼠8周时间点肾脏相对重量及肾脏纤维化程度较正盐组增加,8%高盐组较4%高盐组进一步增加。3)4%高盐组及8%高盐组大鼠8周时间点肾脏组织巨噬细胞浸润增加,8%高盐组较4%高盐组进一步增加。结论:盐浓度不同对盐敏感性肾脏纤维化及巨噬细胞浸润程度影响不同,盐浓度升高可加重盐敏感高血压时肾脏纤维化及及巨噬细胞浸润。     

Increased expression of NAD(P)H oxidase subunit p67(phox) in the renal medulla contributes to excess oxidative stress and salt-sensitive hypertension

NAD(P)H oxidase has been shown to be important in?the development of salt-sensitive hypertension. Here, we show that the expression of a subunit of NAD(P)H oxidase, p67(phox), was increased in response to a high-salt diet in the outer renal medulla of the Dahl salt-sensitive (SS) rat, an animal model for human salt-sensitive hypertension. The higher expression of p67(phox), not the other subunits observed, was associated with higher NAD(P)H oxidase activity and salt sensitivity in SS rats compared with a salt-resistant strain. Genetic mutations of the SS allele of p67(phox) were found in the promoter region and contributed to higher promoter activity than that of the salt-resistant strain. To verify the importance of p67(phox), we disrupted p67(phox) in SS rats using zinc-finger nucleases. These rats exhibited a significant reduction of salt-sensitive hypertension and renal medullary oxidative stress and injury. p67(phox) could represent a target for salt-sensitive hypertension therapy.     

Polymorphisms of EDNRB, ATG, and ACE genes in salt-sensitive hypertension

Almost 50% of hypertensive individuals manifest blood pressure changes in response to salt depletion or repletion and are termed "salt sensitive" (SS). Blunted activity of the endothelin (ET) system and the renin-angiotensin-aldosterone system (RAAS) have been reported as possible mechanisms contributing to salt sensitivity. Data are available that endothelin receptor subtype B (ETBR)-deficient rats develop salt-sensitive hypertension when fed a high-salt diet. Whether the ETBR gene (EDNRB) is involved in genetic predisposition to human salt-sensitive hypertension has not been studied so far. We screened EDNRB in 104 hypertensive patients (49 salt sensitive and 55 salt resistant) and 110 normotensive controls. No new sequence variation was found, but genotype distribution of the common polymorphism G1065A revealed that the AA + GA genotypes were significantly more frequent in salt-resistant than in salt-sensitive individuals (p = 0.007), suggesting a protective role for the A allele. We also screened angiotensinogen gene AGT M235T and angiotensin-converting enzyme insertion/deletion polymorphism ACE I/D and found an association between TT genotype and hypertension. A possible synergistic effect to salt-sensitive hypertension was found by combining EDNRB GG with ACE DD/ID genotypes. In conclusion, our data confirm the role of ET system and RAAS in salt-sensitive hypertension.     

Dopaminergic modulation of salt sensitivity in patients with essential hypertension

The present study was designed to investigate the possible role of dopaminergic mechanisms in contributing to the pathogenesis of hypertension in salt sensitive patients. Eighteen patients with essential hypertension were studied while under a diet ranging from low salt to high salt, which enabled a classification in "salt-sensitive" (SS) and "nonsalt-sensitive" (NSS) groups based on a tentative criteria of a 10% increase of mean blood pressure with high salt diet. The SS patients showed reduced urinary excretion of sodium as compared with that from NSS patients. Urinary norepinephrine excretion in all patients with salt loading was suppressed, but urinary excretion of epinephrine showed a tendency to increase in SS patients after salt loading. Urinary excretion of dopamine increased in NSS patients with salt loading, but did not change in SS patients. To further evaluate the role of dopaminergic mechanisms in salt-sensitive hypertension, metoclopramide, a dopamine antagonist, was injected intravenously to all patients. With salt loading, plasma aldosterone levels increased after injection of metoclopramide in NSS patients, but did not change in SS patients. These results suggest that salt-sensitive hypertension is modulated by dopaminergic activity, which in turn is attenuated in SS patients. Decreased dopaminergic activity induced sodium retention both by a direct effect on the kidney as well as indirectly via relatively increased aldosterone secretion. Both mechanisms would help to increase intravascular volume and blood pressure in salt-sensitive hypertension.     

Computational analysis of candidate disease genes and variants for salt-sensitive hypertension in indigenous Southern Africans

Multiple factors underlie susceptibility to essential hypertension, including a significant genetic and ethnic component, and environmental effects. Blood pressure response of hypertensive individuals to salt is heterogeneous, but salt sensitivity appears more prevalent in people of indigenous African origin. The underlying genetics of salt-sensitive hypertension, however, are poorly understood. In this study, computational methods including text- and data-mining have been used to select and prioritize candidate aetiological genes for salt-sensitive hypertension. Additionally, we have compared allele frequencies and copy number variation for single nucleotide polymorphisms in candidate genes between indigenous Southern African and Caucasian populations, with the aim of identifying candidate genes with significant variability between the population groups: identifying genetic variability between population groups can exploit ethnic differences in disease prevalence to aid with prioritisation of good candidate genes. Our top-ranking candidate genes include parathyroid hormone precursor (PTH) and type-1 angiotensin II receptor (AGTR1). We propose that the candidate genes identified in this study warrant further investigation as potential aetiological genes for salt-sensitive hypertension.     

Blood pressure in a hypertensive mouse model of SLE is not salt-sensitive

Systemic lupus erythematosus (SLE) is a risk factor for hypertension. Previously, we demonstrated that an established mouse model of SLE (female NZBWF1 mice) develops hypertension with renal inflammation and oxidative stress, both characteristics known as contributing mechanisms to the development of salt-sensitive hypertension. On the basis of this model, we hypothesized that blood pressure in SLE mice would be salt-sensitive. Thirty-week-old female SLE and control mice (NZW/LacJ) were fed 8% high-salt (HS) diet or normal diet (0.4% salt) for 4 wk. Plasma levels of double-stranded DNA (dsDNA) autoantibodies, a marker of SLE disease activity, were increased in SLE mice compared with controls (472 ± 148 vs. 57 ± 17 U/ml × 1,000, P < 0.001). HS did not alter dsDNA autoantibody levels in SLE or control mice. Mean arterial pressure was increased in SLE mice compared with controls (132 ± 3 vs. 118 ± 2 mmHg, P < 0.001) and was not significantly altered by the HS diet in either group. Similarly, albuminuria was higher in SLE mice compared with controls (10.7 ± 9.0 vs. 0.3 ± 0.1 mg/day) but was not significantly increased in SLE or control mice fed a HS diet. In summary, blood pressure during SLE is not salt-sensitive, and the HS diet did not adversely affect SLE disease activity or significantly augment albuminuria. These data suggest that renal inflammation and oxidative stress, characteristics common to both SLE and models of salt-sensitive hypertension, may have diverging mechanistic roles in the development of hypertension.     

High dietary cholecalciferol increases plasma 25-hydroxycholecalciferol concentration, but does not attenuate the hypertension of Dahl salt-sensitive rats fed a high salt diet

The Dahl salt-sensitive rat, a model for salt-induced hypertension, develops hypovitaminosis D during high salt intake, which is caused by loss of protein-bound vitamin D metabolites into urine. We tested the hypothesis that high dietary cholecalciferol (5- and 10-fold standard) would increase plasma 25-hydroxycholecalciferol (25-OHD(3)) concentration (indicator of vitamin D status) of salt-sensitive rats during high salt intake. Salt-sensitive rats were fed 0.3% salt (low salt, LS), 3% salt (HS), 3% salt and 7.5 microg cholecalciferol/d (HS-D5), or 3% salt and 15 microg cholecalciferol/d (HS-D10) and sacrificed at week 4. Plasma 25-OHD(3) concentrations of the two groups of HS-D rats were similar to that of LS rats and more than twice that of HS rats. Urinary cholecalciferol metabolite content of HS-D rats was more than seven times that of HS rats. Systolic blood pressures of the hypertensive HS and HS-D rats did not significantly differ, whereas LS rats were not hypertensive. We conclude that high dietary cholecalciferol increases plasma 25-OHD(3) concentration, but does not attenuate the hypertension of salt-sensitive rats during high salt intake. Low salt intake may be necessary to both maintain optimal vitamin D status and prevent hypertension in salt-sensitive individuals.     

Catecholamines and atrial natriuretic factor in Dahl and spontaneously hypertensive rats

We have previously demonstrated two different catecholaminergic patterns in genetic and experimental hypertension: a hyperdopaminergic state in spontaneously hypertensive (Okamoto) rats (SHR) and a hypernoradrenergic state in salt-sensitive Dahl rats. Plasma immunoreactive atrial natriuretic factor (IR ANF) concentrations increase in both models as a response to hypertension. To distinguish between the genetic and acquired components of these abnormalities, we measured adrenal dopamine-beta-hydroxylase (D beta H) activity and coeliac ganglionic atrial natriuretic factor (ANF) like immunoreactivity in the two animal strains. While adrenal D beta H activity was increased in Dahl S rats, it was diminished in SHR in the prehypertensive as well as in the hypertensive stages. In the hypertensive stage, the ANF-like immunoreactivity in the coeliac ganglia was lower in the Dahl S group but higher in SHR than in their respective normotensive controls; there were no changes in these animals when they were prehypertensive. Differences in D beta H activity, which determines the fine tuning of sympathoadrenomedullary catecholamine synthesis may account for the inheritance of mechanisms resulting in salt-sensitive hypertension (as in SHR) or salt-dependent hypertension (as in Dahl salt-sensitive rats). In contrast, plasma IR ANF concentrations may reflect a defense mechanism against hypertension. However ANF-like immunoreactivity in coeliac ganglia does not follow its plasma concentrations and changes in different directions in the two hypertensive strains; it may reflect a neuromodulatory function of ANF in the ganglionic neurotransmission and different implications of this role of ANF in the two hypertensive models.     

Effect of an exercise regimen on development of hypertension in rats

The possibility that a forced exercise regimen might prevent the development of hypertension induced in rats both by renal encapsulation and chronic administration of deoxycorticosterone acetate (DOCA) and NaCl has been studied. In renal hypertensive rats, forced exercise at 0.4 to 1.25 miles/day, 7 days/wk for 16-22 wk failed to prevent the development of hypertension and cardiomegaly and reduced renal concentrating ability accompanying the hypertension. In DOCA-treated rats (10 mg/wk), forced exercise at 0.4 and 0.8 mile/day, 7 days/wk for 16 wk also failed to prevent both the development of hypertension and cardiomegaly. A review of data of others reveals that exercise may delay the development of hypertension in both Dahl salt-sensitive and spontaneously hypertensive (SHR) rats and may modestly reduce the maximal level of pressure attained. Of the four models of hypertension studied to date in rats, the Dahl salt-sensitive strain appears to be the one that responded best to exercise, although blood pressure eventually reached that of sedentary controls.     

Aldosterone-induced abnormal regulation of ENaC and SGK1 in Dahl salt-sensitive rat

Aldosterone plays a crucial role in controlling mineral balance in our body. The mechanism of aldosterone has been reported to elevate renal Na+ reabsorption by stimulating expression of epithelial Na+ channel (ENaC) and also activate an ENaC-regulating protein kinase, serum and glucocorticoid-regulated kinase 1 (SGK1). However, it is unknown whether aldosterone shows its stimulatory action on ENaC and SGK1 under an abnormal, salt-sensitive hypertensive condition. To clarify this point, we studied how aldosterone regulates expression of ENaC and SGK1 in Dahl salt-sensitive (DS) rat that shows hypertension with high salt diet. RNA and protein were extracted from the kidney 6 h after application of aldosterone (1.5 mg/kg body weight) subcutaneously injected into adrenalectomized DS and Dahl salt-resistant (DR) rats. Aldosterone decreased mRNA expression of beta- and gamma-ENaC in DS rat unlike DR rat, while aldosterone increased alpha-ENaC mRNA expression in DS rat similar to DR rat. Further, we found that aldosterone elevated SGK1 expression in DR rat, but not in DS rat. These observations indicate that ENaC and SGK1 are abnormally regulated by aldosterone in salt-sensitive hypertensive rats, suggesting that disturbance of the aldosterone regulation would be one of factors causing salt-sensitive hypertension.