替米沙坦对肝脏和骨骼肌细胞脂蛋白脂肪酶表达的影响

目的 通过观察替米沙坦对HepG2细胞和C2C12细胞过氧化物酶体激增剂激活受体(PPAR)α和脂蛋白脂肪酶(LPL)表达的影响,以探讨其改善脂肪酸代谢的机制.方法 在HepG2细胞和诱导成熟后的C2C12细胞中加入不同浓度的替米沙坦培养48h以及同一浓度替米沙坦作用的不同时间,应用RT-PCR方法检测PPAR-α和LPL mRNA的表达,用Western blot杂交法检测PPARα和LPL蛋白的表达.然后在HepG2细胞中用PPARα选择性拮抗剂MK886阻断替米沙坦作用,24h后观察LPL mRNA的表达.结果 (1)替米沙坦呈剂量和时间依赖性增强HepG2细胞中PPARα和LPL mRNA和其蛋白质的表达,但对C2C12中PPARα和LPL的表达无明显影响.(2)替米沙坦对HepG2细胞中LPL mRNA的上调作用可以被MK886抑制.结论 替米沙坦在人类肝脏细胞中可以同时上调PPARα和LPL的表达,并且对LPL的调节作用是通过PPARα介导的.     

高盐诱导Wistar大鼠肾损害的机制及替米沙坦的干预效果

目的探讨长期高盐饮食导致Wistar大鼠肾脏损害的机制及替米沙坦干预效果。方法雄性Wistar大鼠49只,随机分为对照组(NS组,n=13,用含0.5%Na Cl颗粒饲料喂养)、高盐组(n=24,用含8%Na Cl颗粒饲料喂养)、干预组(GY组,n=12,用含8%Na Cl颗粒饲料喂养+替米沙坦灌胃),均自由饮水,饲养24 w。实验结束时用尾动脉测压仪测血压,用代谢笼收集24 h尿液测定尿蛋白量,HE染色观察肾皮质形态学的改变,生化方法测定肾组织超氧化物歧化酶(SOD)、丙二醛(MDA)、钠泵(Na+-K+-ATPase)和钙泵(Ca2+-ATPase)活性;Western印迹法检测肾组织过氧化物酶体增殖物激活受体γ(PPAR-γ)蛋白的表达。结果与NS组比较,24 w时高盐组部分大鼠血压增高,将血压升高大鼠,分为高盐高血压组(HH组,n=13)其余大鼠分为高盐正常血压组(HN组,n=11);HH组和HN组大鼠肾组织均有大量炎症细胞浸润,尿蛋白排泄增多,总SOD活力、Ca2+-ATPase活性降低(P0.05),PPAR-γ蛋白表达增高(P0.05),而GY组大鼠肾组织炎症细胞浸润程度、尿蛋白排泄量均较高盐组低。结论长期高盐饮食饲养可导致Wistar大鼠的肾损害,其可能与炎症和氧化应激有关,PPAR-γ蛋白表达的增高可能对肾损害有拮抗作用。替米沙坦可能通过降低尿蛋白的排泄和抑制炎症反应对肾脏起保护作用。     

替米沙坦对OLETF大鼠皮下和内脏脂肪组织PPARγ表达的影响

目的 探讨替米沙坦对高脂饲养的OLETF大鼠皮下、内脏脂肪组织中过氧化物酶体增殖物活化受体(PPAR)γ1、PPARγ2基因表达的调控作用及其部位差异性.方法 4周龄雄性OLETF大鼠30只,性别、周龄匹配的正常非糖尿病LETO大鼠12只作为对照,OLETF大鼠从8周龄开始给予高脂喂养,22周龄时,口服葡萄糖耐量试验(OGTT)未发生临床糖尿病或糖耐量减低.之后将这些糖尿病前期OLETF大鼠按照随机数字表法分为替米沙坦干预组(O-T组,5 mg· kg-1 ·d-1,n=10)、吡格列酮干预组(O-P组,10 mg·kg-1·d-1,n=8)和无干预对照组(O-C组,生理盐水,n=10),LETO大鼠为对照组(n=12).48周龄时,复查OGTT,计算稳态模型评估-胰岛素抵抗指数(HOMA-IR).ELISA法测定血清PPARγ的水平,实时PCR检测皮下和睾周脂肪组织中PPARγ1和PPARγ2的基因表达,并测定各组脂肪细胞的面积.结果 与O-C组相比,O-T组皮下脂肪中PPARγ2的表达明显升高(P＜0.01),且O-T组与O-P组之间差异无统计学意义.O-T组内脏脂肪组织中PPARγ1和PPARγ2的表达也明显上调(P＜0.01),HOMA-IR与内脏脂肪组织中PPARγ2的mRNA表达水平呈负相关(ρ=-0.369,P=0.021).与O-C组相比,O-T组脂肪细胞面积减少56％(P＜0.01).结论替米沙坦可部分激活PPARγ,上调皮下及内脏脂肪组织中PPARγ1和PPARγ2的表达,减小脂肪细胞面积,增加胰岛素敏感性.     

替米沙坦减轻高糖引起的人血管内皮细胞损伤

目的 探讨替米沙坦对高糖环境下人血管内皮细胞的保护作用及相关的机制.方法 替米沙坦及不同浓度葡萄糖(5、30 mmol/L)分别作用于培养的脐带静脉内皮细胞(HUVEC)0、12、24、36、48 h,比色法测定细胞培养上清中超氧化物歧化酶(SOD)活性和丙二醛(MDA)水平;收集培养24 h的内皮细胞,蛋白质免疫印迹法(Western-blot)检测过氧化物酶体增殖物激活受体γ(PPAR-γ)蛋白表达量.结果 在高糖处理的细胞条件培养上清中MDA含量升高[干预前:(1 2±0 06)mmol/mL vs干预后:(1 6±0 1)mmol/mL, P<0 05],而SOD活性降低[干预前:(22 9±1 4 )nU/mL vs干预后:(19 4±1 0)nU/mL, P<0 05],同时细胞PPAR-γ蛋白表达量降低(P<0 05);而替米沙坦(1×10-6 mol/L)减轻上述不良变化,降低内皮细胞MDA 含量、增强SOD[MDA:(1 4±0 1)mmol/mL,SOD:(20 7±0 3)nU/mL],以及促进PPAR-γ蛋白质含量增加(P<0 05).结论 替米沙坦可抑制高糖诱导的内皮细胞活性氧产生,增强抗氧化酶活性,维持高糖状态下细胞氧化平衡,促进PPAR-γ蛋白分泌,提示替米沙坦对高糖状态下的内皮细胞具有保护作用,其作用机制可能与调节内皮细胞氧化平衡和激动PPAR-γ有关.     

替米沙坦减轻高糖引起的人血管内皮细胞损伤

目的探讨替米沙坦对高糖环境下人血管内皮细胞的保护作用及相关的机制。方法替米沙坦及不同浓度葡萄糖(5、30 mmol/L)分别作用于培养的脐带静脉内皮细胞(HUVEC)0、12、24、36、48 h,比色法测定细胞培养上清中超氧化物歧化酶(SOD)活性和丙二醛(MDA)水平;收集培养24 h 的内皮细胞,蛋白质免疫印迹法(Western-blot)检测过氧化物酶体增殖物激活受体γ(PPAR-γ)蛋白表达量。结果在高糖处理的细胞条件培养上清中 MDA 含量升高[干预前:(1.2±0.06)mmol/mL vs 干预后:(1.6±0.1)mmol/mL,P<0.05],而 SOD活性降低[干预前:(22.9±1.4)nU/mL vs 干预后:(19.4±1.0)nU/mL,P<0.05],同时细胞 PPAR-γ蛋白表达量降低(P<0.05);而替米沙坦(1×10~(-6)mol/L)减轻上述不良变化,降低内皮细胞 MDA 含量、增强 SOD[MDA:(1.4±0.1)mmol/mL,SOD:(20.7±0.3)nU/mL],以及促进 PPAR-γ蛋白质含量增加(P<0.05)。结论替米沙坦可抑制高糖诱导的内皮细胞活...     

替米沙坦抑制Mtdh表达激活自噬在改善腹膜纤维化中的作用

目的:探究替米沙坦对腹膜透析相关性腹膜纤维化的影响及异黏蛋白metadherin(Mtdh)和自噬在其中的作用.方法:采用4.25％葡萄糖腹膜透析液建立小鼠腹膜透析相关性腹膜纤维化模型和转化生长因子βl(TGF-β1)诱导的腹膜间皮细胞间质转分化模型.C57BL/6J小鼠按体重随机分为对照组、模型组及替米沙坦干预组;M...     

替米沙坦保护胰岛β细胞功能的研究进展

替米沙坦作为血管紧张素Ⅱ受体拮抗剂(ARBs),兼具有部分过氧化物酶体增殖物活化受体γ (PPARγ)激动剂的作用.研究提示,除降压作用外,其还有一定的改善胰岛素抵抗的作用.近年发现,替米沙坦也能够保护胰岛β细胞功能.其机制主要与阻断肾素-血管紧张素系统(RAS)和激活PPARγ有关.     

替米沙坦对非酒精性脂肪性肝炎大鼠的保护作用及其机制

目的 观察替米沙坦通过激活过氧化物酶体增殖因子活化受体γ(PPAR γ)对非酒精性脂肪性肝炎大鼠的保护作用.方法 将30只雄性SD大鼠随机分为对照组、模型组和干预组,每组10只.模型组和干预组给予高脂饲料喂养16周诱发脂肪性肝炎,其中干预组于高脂喂养12周后,给予替米沙坦(5 mg·kg-1·d-1)灌胃治疗4周.16周末处死大鼠,分别进行如下检测:(1)光学显微镜下观察肝脏病理变化;(2)检测血清ALT、AST、空腹胰岛素(FINS)、空腹血糖(FBG)、肿瘤坏死因子α(TNF α)和脂联素水平,计算稳态模型的胰岛素抵抗指数(HOMA-IR);(3)用半定量逆转录-聚合酶链反应和Western blot检测肝组织过氧化物酶体增殖物激活受体γ(PPAR γ)mRNA和蛋白的表达水平.用SPSS 13.0统计软件处理,计量资料以均数±标准差(x-±s)表示,多组间比较用单因素方差分析,组间比较用Student-Newman-Keuls q检验,等级资料组间比较用秩和检验,脂联素、TNF α与HOMA-IR的关联性用直线相关分析.结果 (1)模型组大鼠造模均成功,根据肝细胞脂肪变性占所获肝组织标本量的范围分为4度(F0～4),其中模型组大鼠肝细胞脂肪变程度达F3、F4的分别有1、9只.干预组脂肪变性程度达F1、F2、F3的大鼠分别有1、6、3只.对照组大鼠肝组织炎症活动度积分为0.模型组大鼠肝组织炎症活动度积分为2.67±0.27,与对照组比较,U=15,P＜0.01,差异有统计学意义.干预组炎症活动度积分为1.36±0.12,与模型组比较,U=24,P＜0.05,差异有统计学意义.(2)对照组ALT、AST、FBG、FINS、HOMA-IR、TNF α分别为(48.20±10.99)U/L、(153.00±45.06)U/L、(4.58±1.00)mmol/L、(10.48±1.46)μU/ml、2.13±0.29、(1.38±0.75)μg/L,模型组分别为(114.00±19.7)U/L、(265.33±52.10)U/L、(6.58±0.86)mmoL/L、(20.73±0.91)μ U/ml、6.23±0.10、(3.47±0.19)μg/L,干预组分别为(78.80±15.64)U/L、(211.83±65.51)U/L、(5.38±0.88)mmol/L、(15.02±1.22)μU/ml、3.59±0.29、(1.58±0.13)μg/L,与对照组比较,模型组血清ALT、AST、FINS、FBG、HOMA-IR、TNF α升高,q值分别为13.130、6.472、6.909、26.619、49.683、14.591,P值均＜0.01,差异有统计学意义.与模型组比较,干预组血清ALT、FINS、FBG、HOMA-IR、TNFα降低,q值分别为7.024、4.145、14.829、31.991、13.195,P值均＜0.01,差异有统计学意义.(3)对照组血清脂联素、肝组织PPARγ mRNA和蛋白的表达分别为(8.93±0.44)mg/L、1.19±0.35、0.93±0.44,干预组分别为(7.12±1.00)mg/L、0.79±0.15、0.58±1.00,模型组分别为(6.09±0.96)mg/L、0.57±0.09、0.36±0.96.对照组与模型组比较,q值分别为10.696、8.679、16.762,P值均＜0.05,差异均有统计学意义;干预组与模型组比较,q值分别为3.879、3.079、6.400,P值均＜0.05,差异均有统计学意义.相关分析显示,脂联素水平与HOMA-IR呈负相关(r=-0.891,P＜0.01),TNFα水平与HOMA-IR呈正相关(r=0.927,P＜0.01).结论 替米沙坦可能通过促进PPARγ的表达对NASH大鼠产生保护作用.     

替米沙坦对缺血再灌注兔心肌细胞凋亡的影响

目的 探讨替米沙坦对缺血再灌注兔心肌细胞凋亡的影响.方法 48只雄性新西兰大白兔随机分为6组:假手术组、缺血再灌注模型组、GW9662组、替米沙坦组、替米沙坦+GW9662组、坎地沙坦组,每组8只.灌胃给药2周,假手术组左前降支近端穿线但不结扎,其余5组予60 min缺血,360 min再灌注.采用放射免疫法检测心肌血管紧张素Ⅱ含量,双波长荧光分光光度法测定心肌细胞内游离钙浓度,免疫印迹法测定过氧化体增殖物激活型受体γ蛋白的表达,透射电镜和末端标记法检测心肌细胞凋亡.结果 缺血再灌注模型组、GW9662组、替米沙坦组、替米沙坦+GW9662组及坎地沙坦组心肌血管紧张素Ⅱ含量均较假手术组明显增高(P<0.01).替米沙坦组过氧化体增殖物激活型受体γ蛋白的表达明显高于其余各组(P<0.01).电镜显示,替米沙坦、替米沙坦+GW9662及坎地沙坦抑制心肌缺血再灌注诱导的心肌细胞凋亡的特征性形态学改变如核染色质浓缩边集,出现凋亡小体等.与缺血再灌注模型组比较,替米沙坦组、替米沙坦+GW9662组和坎地沙坦组心肌细胞游离钙浓度、凋亡指数均明显降低(P<0.01);替米沙坦组凋亡指数显著低于替米沙坦+GW9662组和坎地沙坦组(P<0.01).结论 替米沙坦通过阻断血管紧张素Ⅱ1型受体降低细胞内钙浓度,并通过上调过氧化体增殖物激活型受体γ的表达,抑制兔缺血再灌注心肌细胞凋亡而发挥心肌保护效应.     

脂肪细胞胆固醇代谢及其病理生理意义

脂肪组织是体内最大的游离胆固醇储存池,而且对血循环胆固醇代谢起缓冲作用。脂肪细胞胆固醇代谢与其对甘油三酯的储存密切相关,胆固醇可能作为感应脂肪细胞能量储存状态的细胞内信号分子,参与介导肥大脂肪细胞所出现的一些代谢功能异常。     

Regulation of cholesterol 7α-hydroxylation by cholesterol synthesis in rat liver

Hepatic cholesterol 7α-hydroxylation and cholesterogenesis were determined in vitro at various time intervals 6 hr after oral or intravenous administration to fasted rats. Glucose administration to fasted rats enhanced cholesterol 7α-hydroxylation as well as fatty acid or cholesterol synthesis in the liver, though significant changes were not demonstrated in the cholesterol content of liver and serum throughout the observed periods. Hepatic cholesterol synthesis increased 1 hr after oral glucose ingestion. On the other hand, cholesterol 7α-hydroxylation was stimulated 2 hr after oral glucose administration, with a lag phase of 1 hr following the induction of cholesterol synthesis. From the results of the experiments on the effect of glucose ingestion, it appeared that cholesterol 7α-hydroxylation was correlated with hepatic cholesterogenesis.Hepatic cholesterogenesis was decreased in triparanol-treated rats and was not stimulated by glucose administration. Triparanol did not affect cholesterol hydroxylation in the fasted state, but did abolish the stimulatory effect of glucose.Short-term feeding of a high-cholesterol diet, which suppressed hepatic cholesterol synthesis, stimulated cholesterol 7α-hydroxylation. Oral administration of glucose to cholesterol-fed rats still further accelerated hydroxylation.In rats with ligated bile ducts, hepatic cholesterogenesis increased 24 hr after bileduct ligation while hydroxylation decreased 24 hr after the operation but was stimulated after 72 hr. Glucose ingestion by these rats stimulated both cholesterol synthesis and hydroxylation.It is concluded that increased hepatic cholesterogenesis enhances cholesterol 7α-hydroxylase activity; this activity does not depend upon increased fatty acid or other lipid synthesis, altered bile flow or gastrointestinal factors. Increased dietary cholesterol intake also accelerates hydroxylase activity. These mechanisms may preserve homeostasis in the serum cholesterol level, and an altered balance between these two enzyme systems — anabolic and catabolic — probably induces a change in the size of the body cholesterol pool.     

替米沙坦对老年原发性高血压患者降压和改善糖、脂代谢的研究

目的观察替米沙坦对老年高血压病患者降压疗效和对糖、脂代谢的影响。方法选择95例60岁以上的老年高血压病患者,停用其他降压药物2周以上,口服替米沙坦治疗8周,观察治疗第4周和第8周与治疗前相比的血压、血糖、胰岛素、糖化血红蛋白及血脂水平。结果与治疗前比较,替米沙坦治疗4周后血压及24h动态血压均有显著下降（P〈0．05）。治疗后血糖、血清胰岛素、糖化血红蛋白明显降低（P〈0．05）。血清胆固醇、甘油三酯、低密度脂蛋白胆同醇水平显著下降（P〈0．05）,高密度脂蛋白（HDL）显著上升（P〈0．05）。结论替米沙坦除了有较好的降压效果外,还可以改善糖代谢和脂代谢,对于老年高血压病患者尤其是代谢紊乱者有较好的疗效。     

The differential effects of angiotensin II type 1 receptor blockers on microalbuminuria in relation to low-grade inflammation in metabolic hypertensive patients

BACKGROUND: A dual angiotensin type 1 receptor blocker (ARB)/peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist telmisartan may be more useful for microalbuminuria reduction than ARBs with no PPARgamma agonistic action. We investigated whether there is a difference between the effects of telmisartan and valsartan with respect to microalbuminuria reduction, and the association with improvement of metabolic features or suppression of the inflammatory state. METHODS: Fifty-three patients who had metabolic syndrome and had been taking valsartan were recruited. All of these patients were randomly assigned to replace valsartan by telmisartan (telmisartan group; n = 30) or to keep taking valsartan (control group; n = 21). Various parameters were measured at baseline and 12 weeks after randomization. RESULTS: There were no significant changes in blood pressure (BP), glucose, and lipid parameters between baseline and 12 weeks after randomization in either group. There was a significant increase in high molecular weight adiponectin in the telmisartan group (4.6 v 5.0 microg/mL, P = .024), whereas there was no significant change in the control group. The reductions of microalbuminuria and high-sensitivity C-reactive protein (hs-CRP) were significant in the telmisartan group (28.1 v 18.9 mg/g.Cr and 0.77 v 0.60 mg/L, respectively, P = .001 and P = .022), whereas there was no significant change in the control group. The reductions of microalbuminuria and hs-CRP were significantly correlated with each other (gamma = 0.413, P = .003). CONCLUSIONS: The dual ARB/PPARgamma agonist telmisartan achieved more microalbuminuria reduction than an ARB with no PPARgamma agonistic action, possibly through suppression of the inflammatory state in metabolic hypertensive patients.     

微小RNA及自噬现象与几种肝脏疾病的关系

近年来,国内外在肝脏疾病的基础与临床研究领域取得了不少进展,本期及下期杂志已邀请有关专家分别从乙型病毒性肝炎、丙型病毒性肝炎、脂肪性肝病、肝纤维化、自身免疫性肝病、肝癌及肝脏外科病理学等方面进行总结和回顾.本文仅对微小RNA(microRNAs,miRNAs)与病毒性肝炎、脂肪肝、肝纤维化及肝细胞癌等疾病的关系进行简要介绍,以期引起本刊读者的兴趣.     

Role of autophagy in differential sensitivity of hepatocarcinoma cells to sorafenib

AIM: To investigate the role of sorafenib(SFN) in autophagy of hepatocellular carcinoma(HCC). We evaluated how SFN affects autophagy signaling pathway in human HCC cell lines. METHODS: Two different human HCC cell lines, Hep3 B and Huh7, were subjected to different concentrations of SFN. Cell viability and onset of apoptosis were determined with colorimetric assay and immunoblotting analysis, respectively. The changes in autophagy-related proteins, including LC3, ULK1, AMPK, and LKB, were determined with immunoblotting analysis in the presence or absence of SFN. To assess autophagic dynamics, autophagic flux was measured with chloroquine, a lysosomal inhibitor. The autophagic responsiveness between different HCC cell lines was compared under the autophagy enhancing conditions.RESULTS: Hep3 B cells were significantly more resistant to SFN than Huh7 cells. Immunoblotting analysis revealed a marked increase in SFN-mediated autophagy flux in Huh7 cells, which was, however, absent in Hep3 B cells. While both starvation and rapamycin enhanced autophagy in Huh7 cells, only rapamycin increased autophagy in Hep3 B cells. Immunoblotting analysis of autophagy initiation proteins showed that SFN substantially increased phosphorylation of AMPK and consequently autophagy in Huh7, but not in Hep3 B cells.CONCLUSION: The autophagic responsiveness to SFN is distinct between Hep3 B and Huh7 cells. Resistance of Hep3 B cells to SFN may be associated with altered autophagy signaling pathways.     

自噬与肝脏脂代谢

细胞自噬是利用溶酶体降解受损的细胞器、未折叠蛋白来维持细胞内稳态,在机体生长、发育和衰老中均起重要作用.研究表明,自噬可能与肝脏脂肪合成及分解相关.固醇调节元件结合蛋白通路、转录因子、激素与营养因素可能会影响自噬,从而改变脂代谢.     

Cdk5与替米沙坦2型糖尿病预防作用的关系

细胞周期素依赖性蛋白激酶(Cdk)5介导的过氧化物酶体增殖物活化受体(PPAR)γ磷酸化通过干扰脂联素等胰岛素敏感性相关细胞因子的基因表达,引起胰岛素抵抗并最终引发2型糖尿病.替米沙坦一方面通过改变PPARγ的蛋白构象使其273位丝氨酸不能与Cdk5结合来调控PPARγ功能;另一方面,作为抑制血管紧张素Ⅱ1型受体阻断剂...     

Emerging roles of the intestine in control of cholesterol metabolism

INTRODUCTIONMaintenance of cholesterol homeostasis in the body requires accurate metabolic cross-talk between processes that govern de novo cholesterol synthesis and turnover to adequately cope with(large)fluctuations in dietary cholesterol intake.Imbalance may lead to elevated plasma cholesterol levels and increased risk for cardiovascular diseases(CVD),the main cause of death in Western society.A multitude of epidemiological studies has shown the direct link between high plasma cholest…     

Endoplasmic reticulum and autophagy in rat hepatocytes.

Electron microscopy of hepatocytes in both normal rat liver and rat liver treated to induce hyperplasia of smooth endoplasmic reticulum shows that autophagic vacuoles and residual bodies (types of lysosomes) are continuous with endoplasmic reticulum.