慢性肾脏病患者尿血管紧张素原与肾脏肾素血管紧张素系统活性的相关性

目的 探讨慢性肾脏病（CKD）患者尿血管紧张素原（AGT）与肾损伤指标及肾脏局部肾素血管紧张素系统（RAS）活性的关系。 方法 用放射免疫法和酶联免疫吸附法（ELISA）测定血、尿RAS组分的浓度,并用免疫组织化学方法评价肾内肾素、AGT、血管紧张素Ⅱ（Ang Ⅱ）和血管紧张素Ⅱ受体的表达。分析129例CKD患者尿AGT与临床指标的相关性以及73例行肾组织活检的CKD患者尿AGT与肾脏局部RAS组分表达的相关性。 结果 129例CKD患者尿AGT （159.08±125.18）μg/g Cr,Scr（113.20±105.05） μmol/L,估算肾小球滤过率(eGFR)（58.52±27.15） ml·min-1·(1.73 m2)-1,尿蛋白量（2.03±2.65） g/24 h,尿AngⅡ（164.71±139.25） ng/g Cr,尿Ⅳ型胶原（447.60±800.66）μg/g Cr,尿钠（162.17±81.61） mmol/24 h。 经Pearson单因素相关分析,尿AGT与eGFR （r = -0.55,P < 0.01）、尿钠 （r = -0.20, P < 0.05）呈负相关;与Scr（r = 0.51,P < 0.01）、24 h尿蛋白量（r = 0.30,P < 0.01）、尿Ang Ⅱ（r = 0.20, P < 0.05）及尿Ⅳ型胶原（r = 0.47,P < 0.01）呈正相关。多元回归分析发现尿AGT与eGFR呈负相关（P < 0.01）,与Scr（P < 0.01）、24 h尿蛋白量（P < 0.05）、尿AngⅡ（P < 0.05）、尿Ⅳ型胶原（P < 0.01）呈正相关。73例CKD患者肾活检组织中,尿AGT与肾脏AGT（r = 0.45,P < 0.01）、AngⅡ（r = 0.52,P < 0.01）和AngⅡ 1型受体（r = 0.28,P < 0.05）免疫组化阳性面积呈正相关。 结论 尿AGT可能是反映CKD肾脏损伤尤其是慢性损伤程度的指标,可作为肾脏局部AngⅡ活性的无创评价指标。     

Obesity-related genes variability in Czech patients with sporadic colorectal cancer: preliminary results

Background  Genetic variability in obesity-related genes and the resulting phenotypes are being recognized as major risk factors for colorectal cancer and/or severity of the disease. Materials and methods  A total of 102 patients (aged 68 ± 10.2 years, 79 men and 23 women) and 101 age-matched (68.1 ± 5.4 years old) individuals without colorectal cancer, 59 men and 42 women, were recruited. All the individuals were genotyped for the following subset of polymorphisms in obesity-related genes: angiotensinogen gene (M235T and -6A/G), in IL-6 gene (-174 G/C and -596 A/G), in leptin gene (-2548 A/G), and polymorphism Gln223Arg within the leptin receptor (LEPR) gene. Results  A significant increase in frequency of double heterozygote genotype (MTAG) of both angiotensinogen polymorphisms in males with colorectal cancer was observed when compared to control men [odds ratio (OR) = 3.77, P _corr = 0.001]. A marginally significant difference in genotype distribution of -174 G/C IL-6 polymorphism between the patients in stage I–II compared to patients in III–IV was found (P _g = 0.05, P _a = 0.173). The GG genotype of -174 G/C IL-6 polymorphism in the patients in stage III–IV carries an increased risk compared to those in stage I–II (OR = 2.83, P _corr = 0.06). Similarly, a difference in genotype distribution of Gln223Arg in LEPR gene between the patients staged I–II compared to III–IV was observed (P _g = 0.05). The AA genotype was shown to be risky for the patients staged III–IV (OR = 3.35, P _corr = 0.06). Conclusions  The investigated single nucleotide polymorphisms within the genes encoding for obesity-related genes were observed to be associated both with clinical manifestation of colorectal cancer and with severity of the disease. Thus, we suggest that defined genetic variability in the genes might become DNA markers for colorectal cancer in the future.     

Differential hypertrophic effects of cardiotrophin-1 on adult cardiomyocytes from normotensive and spontaneously hypertensive rats

Cardiotrophin-1 (CT-1) produces longitudinal elongation of neonatal cardiomyocytes, but its effects in adult cardiomyocytes are not known. Recent observations indicate that CT-1 may be involved in pressure overload left ventricular hypertrophy (LVH). We investigated whether the hypertrophic effects of CT-1 are different in cardiomyocytes isolated from adult normotensive and spontaneously hypertensive rats (SHR). Hypertrophy was evaluated by planimetry and confocal microscopy, contractile proteins were quantified by Western blotting and real-time RT-PCR, and intracellular pathways were analyzed with specific chemical inhibitors. CT-1 increased c-fos and ANP expression (p<0.01) and cell area (p<0.01) in cardiomyocytes from both rat strains. In Wistar cells, CT-1 augmented cell length (p<0.01) but did not modify either the transverse diameter or cell depth. In SHR cells, CT-1 increased cell length (p<0.05), cell width (p<0.01) and cell depth, augmented the expression of myosin light chain-2v (MLC-2v) and skeletal alpha-actin (p<0.01) and enhanced MLC-2v phosphorylation (p<0.01). The blockade of gp130 or LIFR abolished CT-1-induced growth in the two cell types. All distinct effects observed in cardiomyocytes from SHR were mediated by STAT3. Baseline angiotensinogen expression was higher in SHR cells, and CT-1 induced a 1.7-fold and 3.2-fold increase of angiotensinogen mRNA in cardiomyocytes from Wistar rats and SHR respectively. In addition, AT1 blockade inhibited the specific effects of CT-1 in SHR cells. Finally, ex vivo determinations revealed that adult SHR exhibited enhanced myocardial CT-1 (mRNA and protein, p<0.01), increased cell width (p<0.01) and concentric LVH compared with pre-hypertensive SHR. These findings reveal a specific cell-broadening effect of CT-1 in cardiomyocytes from adult SHR and suggest that the hypertensive phenotype of these cells may influence the hypertrophic effects of CT-1, probably by means of an exaggerated induction of angiotensinogen expression. We suggest that CT-1 might facilitate LVH in genetic hypertension through a cross-talk with the renin-angiotensin system.     

Caveolin and β1-integrin coordinate angiotensinogen expression in cardiac myocytes

Background

The cardiac renin–angiotensin system (RAS) has been implicated in mediating myocyte hypertrophy and remodeling, although the biochemical mechanisms responsible for regulating the local RAS are poorly understood. Caveolin-1 (Cav-1)/Cav-3 double-knockout mice display cardiac hypertrophy, and in vitro disruption of lipid rafts/caveolae using methyl-β-cyclodextrin (MβCD) abolishes cardiac protection.

Methods

In this study, neonatal rat ventricular myocytes (NRVM) were used to determine whether lipid rafts/caveolae may be involved in the regulation of angiotensinogen (Ao) gene expression, a substrate of the RAS system.

Results

Treatment with MβCD caused a time-dependent upregulation of Ao gene expression, which was associated with differential regulation of mitogen-activated protein (MAP) kinases ERK1/2, p38 and JNK phosphorylation. JNK was highly phosphorylated shortly after MβCD treatment (2–30 min), whereas marked activation of ERK1/2 and p38 occurred much later (2–4 h). β_1D-Integrin was required for MβCD-induced activation of the MAP kinases. Pharmacologic inhibition of ERK1/2 and JNK enhanced MβCD-induced Ao gene expression, whereas p38 blockade inhibited this response. Adenovirus-mediated expression of wild-type p38α enhanced MβCD-induced Ao gene expression; conversely expression of dominant negative p38α blocked the stimulatory effects of MβCD. Expression of Cav-3 siRNA stimulated Ao gene expression, whereas overexpression of Cav-3 was inhibitory. Cav-1 and Cav-3 expression levels were found to be positively regulated by p38, but unaffected by ERK1/2 and JNK.

Conclusion

Collectively, these studies indicate that lipid rafts/caveolae couple to Ao gene expression through a mechanism that involves β₁-integrin and the differential actions of MAP kinase family members.     

AGT基因M235T变异与腰臀比异常对原发性高血压的影响

目的探讨AGT基因第二外显子编码M235T变异与腰臀比异常及其交互作用对原发性高血压的影响。方法对从青岛市4个社区中筛检出的、未经药物系统治疗的235例原发性高血压病人及240例正常血压者进行调查,用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法检测M235T变异;应用相加模型分析M235T变异与腰臀比异常的交互作用。结果高血压组T等位基因频率(46.81%)及腰臀比异常率(69.79%)高于对照组(分别为37.71%,47.92%),差别有统计学意义(χ2=8.677,23.433,P0.01)。AGT基因M235变异与腰臀比异常具有正交互作用。用多因素分析调整年龄、性别、体质指数、饮酒、吸烟、血脂等因素后,M235T基因变异与腰臀比异常的协同效应指数(S)为1.945,归因交互效应(AB)为1.022,归因交互效应百分比(AP%)为32.91%,纯因子间AP为48.55%。结论 AGT基因第二外显子编码M235T变异与原发性高血压有关,AGT基因M235T变异与腰臀比异常具有正交互作用,控制腰臀比异常可以降低居民原发性高血压患病的危险性。     

On the plasticity of the cerebellar renin-angiotensin system: localization of components and effects of mechanical perturbation

This study focuses on the renin-angiotensin system (RAS) in the cerebellar cortex and changes within this system after mechanically induced cerebellar injury. Using radioactive and non-radioactive in situ hybridization and immunocytochemistry angiotensinogen mRNA, angiotensinogen, angiotensin II and, for the first time, N-terminal angiotensin fragment (1–7) immunoreactivities, respectively, were demonstrated in the rat cerebellum. Angiotensinogen mRNA and angiotensinogen immunoreactivity (IR) were both present in glial cell populations of all layers, especially in the Purkinje and granular cell layers and within the cerebellar nuclei. Angiotensin II IR was demonstrated in glial cell population in all layers using a monoclonal angiotensin II antibody, while with a polyclonal angiotensin II antiserum (Denise) some Purkinje cell bodies were labelled. After lesioning the cerebellar cortex mechanically by an injection cannula a strong increase in angiotensinogen gene expression as well as in angiotensin II and angiotensin (1–7) immunoreactivities were observed in the glial cell populations. Furthermore, putative Bergmann glial processes, as indicated from the morphological appearance became strongly angiotensin II and angiotensinogen immunoreactive in the region close to the mechanically induced lesion. It could inter alia be demonstrated for the first time using confocal laser microscopy of ANG II IR and GFAP IR that ANG II in vivo in the intact cerebellar cortex is present in astroglial processes in the molecular layer and presumably secreted into the extracellular space in form of small spheric bodies and/or taken up by other cell types. In contrast, the N-terminal fragment angiotensin (1–7) IR was restricted to the glial cell populations and appeared only after the lesion event. Thus, it is suggested that the cerebellar RAS shows marked changes in response to mechanically induced lesions. The expression of angiotensinogen as well as the production of angiotensinogen IR and angiotensin II like IR is even after mechanical lesion restricted to astrocytes, i.e., cerebellar astrocytes and putataive Bergmann glial cells, and in case of immunoreactivities it spreads to the radially oriented Bergmann glial processes in the molecular layer.     

肥厚型心肌病患者血管紧张素原M235T基因多态性研究

目的 :探讨中国人群血管紧张素原 (AGT)基因多态性与肥厚型心肌病 (HCM )发病的关系。方法 :应用PCR技术扩增AGT基因目的片断 ,检测基因多态性。结果 :HCM患者的AGTT等位基因频率高于对照组(P <0 .0 5 ) ,HCM患者中同时具有AGTT等位基因和血管紧张素转换酶 (ACE)缺失 (D)等位基因及AGTTT ACEDD基因型者明显高于对照组 (P <0 .0 1,P <0 .0 5 ) ,DD TT基因型的HCM患者心脏事件发生率高于其它基因型组合者和AGTTT型者 (P <0 .0 1,P <0 .0 1)。结论 :AGTT等位基因是HCM的危险因素 ,AGTT和ACED等位基因及TT和DD基因型对HCM发病具有协同作用 ,具有ACEDD AGTTT基因型的HCM患者有较严重的临床表型。     

Intrarenal angiotensinogen: localization and regulation

Multiple lines of evidence (physiologic, immunohistochemical, and molecular biologic) support the presence of a complete intrarenal renin-angiotensin system (RAS). Localization of angiotensinogen messenger ribonucleic acid (mRNA) within the proximal tubule, together with demonstration of renin and converting enzyme mRNAs within the kidney, provide the most persuasive evidence for local, independent synthesis. Data from a combination of in situ hybridization studies, Northern analysis, and physiologic manipulations lead us to propose that a major site for action of a local RAS is the proximal tubule. There, locally generated angiotensins may regulate sodium reabsorption and urine pH. A variety of factors appear to regulate renal angiotensinogen. For instance sodium depletion increases the expression of renal angiotensinogen (as well as renin mRNA), as does high potassium intake and androgen administration. In pathologic states, such as experimental heart failure, and certain models of hypertension, such as the spontaneously hypertensive rat, expression of renal angiotensinogen mRNA levels is altered. It is proposed that changes in the intrarenal RAS may play a role in the maintenance of homeostasis and in the pathophysiology of various disease states.     

Antisense inhibition of angiotensinogen attenuates vasopressin release in the paraventricular hypothalamic nucleus of spontaneously hypertensive rats

It has been reported that intracerebroventricularly injected antisense oligonucleotide to angiotensinogen reduces arterial pressure in spontaneously hypertensive rats (SHR), but the mechanism and the sites of action remain unclear. In the present study, we examined whether injection of antisense oligonucleotide to angiotensinogen into the paraventricular hypothalamic nucleus (PVN) would influence arterial pressure and vasopressin release. For this purpose, 12-week-old male SHR were cannulated into the bilateral PVN. One week later, we injected antisense or sense oligonucleotide to angiotensinogen into the bilateral PVN (0.2 nmol/200 nl each side). After 24 h, we directly monitored arterial pressure, and then took blood samples to measure plasma vasopressin, catecholamines and renin activity. Mean arterial pressure did not change in either group (from 144+/-3 to 154+/-4 mmHg for the antisense oligonucleotide group, n=11; from 147+/-4 to 156+/-3 mmHg for the sense oligonucleotide group, n=11). Antisense oligonucleotide attenuated vasopressin release compared with sense oligonucleotide (1.30+/-0.28 vs. 3.29+/-0.60 pg/ml, respectively, P<0.01). Plasma catecholamines also decreased in the antisense oligonucleotide group compared with the sense oligonucleotide group. However, the plasma renin activity did not differ between the groups. In the additional experiment, we examined the neurohormonal and cardiovascular effects of intracerebroventricularly injected antisense oligonucleotide to angiotensinogen in SHR. Mean arterial pressure, plasma vasopressin and plasma norepinephrine were significantly lower in the antisense oligonucleotide group than in the sense oligonucleotide group. These results suggest that angiotensinogen in PVN plays important roles in vasopressin release and sympathetic nerve activity, but may not contribute to the maintenance of arterial pressure in SHR.     

ACE和AGT基因多态性与子宫内膜异位症相关性的研究

目的:探讨ACE基因A240*T和AGT基因M235*T多态性与中国河北省汉族孕龄妇女Ⅲ、Ⅳ期EMs遗传易感性的关系。方法:用病例对照研究法,78例Ⅲ、Ⅳ期EMs患者与82例对照组的外周血白细胞为样本,用PCR-RFLP技术分析ACE基因A240*T和AGT基因M235*T多态性分布频率。结果:ACE基因的3种基因型AA、AT、TT在EMs组和对照组的分布频率分别为:41.0%、43.6%、15.4%;56.1%、39%、4.9%。A/T等位基因在两组的分布频率分别为62.8%、37.2%;75.6%、24.4%,两组差异有统计学意义(P<0.05)。AGT基因3种基因型MM、MT、TT在EMs和对照组的分布频率分别为6.4%、37.2%、56.4%;8.5%、35.4%、56.1%。M/T等位基因在两组的分布频率分别为25%、75%;26.2%、73.8%,两组差异无统计学意义。结论:携带ACE240*T等位基因增加患Ⅲ、Ⅳ期子宫内膜异位症的危险。AGT基因M235*TM/T等位基因在EMs组和对照组的分布无显著差异。