内皮素,一氧化氮与糖尿病肾病

内皮素和一氧化氮是两种作用相反的血管活性物质,影响糖尿病肾病肾脏血流动力学改变,尤其是参与早期肾小球高灌注,高滤过,参与肾脏水,盐电解质平衡调控,影响肾小管间质纤维化过程,其中一氧化氮在糖尿病肾病中具有损伤和保护双重效应。     

糖尿病早期肾脏内皮素的改变

目的：观察内皮素（ＥＴ）是否参与糖尿病早期肾脏高灌注、高滤过的形成。 方法：应用廓清试验观察４周糖尿病大鼠肾血流量（ＲＰＦ）和肾小球滤过率（ＧＦＲ）；应用半定量逆转录聚合酶链式反应（ＲＴ－ＰＣＲ）分别观察肾皮、髓质ＥＴ－１、ＥＴ－３、ＥＴ－Ａ受体及诱生型一氧化氮合成酶（ｉＮＯＳ）的基因表达情况。 结果：４周糖尿病大鼠存在ＲＰＦ、ＧＲＦ升高；肾脏皮质ＥＴ－１、ＥＴ－Ａ受体表达增加。 结论：内皮素可能     

内皮素、一氧化氮与糖尿病肾病

内皮素和一氧化氮是两种作用相反的血管活性物质,影响糖尿病肾病肾脏血流动力学改变,尤其是参与早期肾小球高灌注、高滤过,参与肾脏水、盐电解质平衡调控,影响肾小管间质纤维化进程,其中一氧化氮在糖尿病肾病中具有损伤和保护双重效应     

早期糖尿病大鼠肾脏诱生型一氧化氮合酶基因表达

目的观察４周糖尿病大鼠肾脏血流动力学变化和肾脏皮、髓质诱生型一氧化氮合酶（ｉＮＯＳ）基因表达情况。方法应用整体廓清试验和半定量逆转录聚合酶链反应（ＲＴＰＣＲ）。结果糖尿病大鼠肾血浆流量（ＲＰＦ４．５４±０．２４ｍｌ／ｍｉｎ／１００ｇｗｔ）、肾小球滤过率（ＧＦＲ１．１５±０．０４ｍｌ／ｍｉｎ／１００ｇｗｔ）显著高于正常（ＲＰＦ３．４４±０．５０，ＧＦＲ０．９４±０．０３）；肾脏皮、髓质ｉＮＯＳｍＲＮＡ水平（经ＧＡＰＤＨ校正）亦明显升高（皮质１．４９±０．０１比正常１．００±０．００８；髓质３．９０±０．０８比正常１．００±０．０９）。结论一氧化氮（ＮＯ）增加可能是糖尿病早期肾脏高灌注、高滤过的重要原因。高水平ＮＯ即可直接扩张肾血管，导致ＲＰＦ、ＧＦＲ升高；又可能通过升高肾间质压，抑制管球反馈参与肾小球高灌注、高滤过的形成     

血糖控制不佳可增加2型糖尿病患者肾循环中一氧化氮的活性

已有实验研究显示血糖可促进内皮细胞释放一氧化氮，而后者参与糖尿病模型肾脏高灌注的发生。为此，研究者对血糖控制与2型糖尿病患者。肾脏一氧化氮活性的关系进行研究。研究共纳入113例2型糖尿病患者，记录其肾血流和肾小球滤过率，计算功能型一氧化氮活性、     

一氧化氮和内皮素与早期糖尿病大鼠肾小球高滤过的关系

目的　探讨一氧化氮（ Ｎ Ｏ） 和内皮素（ Ｅ Ｔ） 在早期糖尿病大鼠肾小球高滤过中的作用。方法采用链脲佐菌素（ Ｓ Ｔ Ｚ） 诱导的大鼠糖尿病模型，将糖尿病形成７ ～１４ 天定为早期，观察早期肾脏病变和血浆、组织匀浆中的硝酸盐（ Ｎ Ｏ３ ） 及内皮素水平变化。结果　糖尿病形成早期，肾重／ 体重增加（ Ｐ＜ ０ ．０５） ；且出现大量蛋白尿（ Ｐ＜ ０ ．００１） ；肌酐清除率（ Ｃ Ｃｒ） 明显增高（ Ｐ＜ ０ ．００１） ；血浆及组织匀浆中 Ｎ Ｏ３ 明显增高（ Ｐ＜ ０ ．００５） ，均与 Ｃ Ｃｒ 呈正相关关系；血浆及组织匀浆中 Ｅ Ｔ 水平明显下降（ Ｐ＜ ０ ．００１） 。结论　提示糖尿病早期已有肾脏病变； Ｃ Ｃｒ 升高间接表明肾小球滤过率（ Ｇ Ｆ Ｒ） 升高，研究结果认为 Ｎ Ｏ 是影响糖尿病早期肾小球高滤过的重要介质，而 Ｎ Ｏ 与 Ｅ Ｔ 又可能构成一对具有拮抗效应的血管活性物质，在早期糖尿病鼠肾小球高滤过中起重要的调控作用。     

槲皮素对糖尿病大鼠肾脏的保护作用

目的探讨槲皮素对糖尿病大鼠肾脏保护作用.方法对链脲佐菌素诱导糖尿病大鼠动物模型,给予槲皮素100mg*kg-1*d-1,治疗共8周.放免法测定尿白蛋白排泄率,测定内生肌酐清除率及肾小球蛋白激酶C活力.RT-PCR检测方法观察槲皮素对糖尿病大鼠肾脏皮质TGF-β1基因表达的影响,观察槲皮素对肾小球形态及病理改变.结果糖尿病大鼠存在肾小球高滤过,尿白蛋白排泄率、肾重/体重、肾小球细胞膜蛋白激酶C活力明显升高.肾脏皮质TGF-β1基因表达显著增加,肾小球肥大.给予槲皮素治疗2周及8周时,糖尿病大鼠肾小球滤过率、尿白蛋白排泄率、肾小球肥大均较糖尿病未治疗组显著降低,肾小球细胞膜蛋白激酶C活力及TGF-β1基因表达显著下降.肾脏病理改变不显著.结论槲皮素通过抑制糖尿病大鼠肾脏蛋白激酶C活力可以纠正糖尿病早期肾脏高滤过、高灌注,并同抑制肾脏皮质TGF-β1基因过度表达有关,抑制蛋白激酶C活性对防治糖尿病肾病尤为重要.     

一氧化氮合成酶抑制剂对糖尿病肾病及其它肾病的影响

由于一氧化氮具有强烈的扩血管作用，其在不同的肾脏疾病中起到保护和非保护的作用。本文就一氧化氮合成酶抑制剂在调节糖尿病肾病早期肾内一氧化氮水平及其对糖尿病肾病血流动力学、肾功能改变的影响作以简要总结，并归纳了近年来一氧化氮合成酶抑制剂在其它肾脏疾病中的影响。     

糖尿病肾小球血流动力学异常的发生机理

早在半个多世纪以前人们就认识到,糖尿病(DM)早期往往伴有肾血浆流量(RPF)、肾小球滤过率(GFR)增高及肾小球肥大。近年研究认为,糖尿病时这种肾脏血流动力学变化与糖尿病肾病(diabeticnephropathy,DN)的发生、发展有着非常密切的关系。在DM伴有单侧肾动脉狭窄者中发现,无肾动脉狭窄侧肾脏表现出明显的DN形态学改变,而有肾动脉狭窄侧肾脏病变则不明显;糖尿病大鼠单侧肾切除,发现残余肾灌注及滤过均增加,结果明显加速实验性DN进展,不同蛋白质饮食对DN进展影响的研究发现,高蛋白饮食可使肾小球内高滤过状态更加明显,从而促进肾小球硬化。上述一系列实验有力地提示,肾脏血流动力学异常是促进DN发生、发展的重要因素。因此,探讨DN肾脏血流动力学异常机理,对于防治DN将具有重要的指导意义。本文简述影响DN肾脏血流动力学的因素及其与DN进展的关系。     

一氧化氮和一氧化氮合酶基因多态性与糖尿病肾病

早期糖尿病肾病的特征改变是肾脏肥大和高滤过,一氧化氮过多一这一改变有关,而在晚期,一氧化氮合成受损,诱导型一氧化氮合酶基因上AAAT多态性与内皮一氧化氮合酶基因上27个碱基重复序列多态性与糖尿病肾病的发生与进展有关,而（CCTTT）n多态性主要与糖尿病肾病危险性降低有关。内皮一氧化氮合酶第13内含子上的多态性与高血压有关,而（27碱基）4等位基因与糖尿病肾病风险增加密切有关。     

依那普利对糖尿病大鼠肾脏保护作用的实验研究

目的 研究依那普利对糖尿病大鼠肾脏的保护作用。方法 应用依那普利对糖尿病大鼠进行了１０周治疗,观察了其对糖尿病大鼠肾脏的保护作用。结果 对照组糖尿病大鼠肾小球滤过度,肾血流量,滤过分数及尿白蛋白均较正常对照组明显升高,肾小球基底膜不规则增厚,突触融合。依那普利治疗后糖尿病大鼠ＧＦＲ,ＲＰＦ,ＦＦ及ＵＡ均较糖尿病对照组明显降低,病理学异常不明显。     

Prevention of glomerular hyperfiltration in rats with streptozotocin-induced diabetes by an atrial natriuretic peptide receptor antagonist

Summary The contribution of atrial natriuretic peptide (ANP) to the development of glomerular hyperfiltration in diabetes was investigated by examining the effects of HS-142-1, a non-peptide antagonist of biological receptors for ANP, on glomerular filtration rate (GFR) and renal plasma flow (RPF) in rats with streptozotocin-induced diabetes. Three to four weeks after streptozotocin injection, the plasma concentration of ANP, urinary cyclic GMP excretion rate, GFR, and RPF were significantly higher in diabetic rats than in control rats. The increase in GFR and RPF in diabetic rats was significantly reduced, in a dose-dependent manner, by a single intravenous injection of HS-142-1; the maximal effect was apparent at a dose of 10 mg per kg of body weight. Continuous subcutaneous administration of HS-142-1 with an osmotic minipump for 3 to 4 weeks, beginning 2 days after streptozotocin injection, prevented the increases in urinary cyclic GMP excretion rate, GFR, and RPF observed in untreated diabetic rats. These results highlight the importance of ANP in the development of diabetic glomerular hyperfiltration and indicate that this condition can be prevented by continuous inhibition of the action of ANP.Abbreviations ANP Atrial natriuretic peptide - GFR glomerular filtration rate - RPF renal plasma flow - PAH para-aminohippurate     

糖尿病大鼠肾脏一氧化氮系统基因表达的研究

目的 研究糖尿病大鼠肾脏一氧化氮系统基因的表达。方法 观察了１２周ＳＴＺ－糖尿病大鼠肾脏皮质一氧化氮（ＮＯ）含量及一氧化氮合成酶（ＮＯＳ）活力,并应用ＲＴ－ＰＣＲ技术检测了肾脏皮质诱生型一氧化氮合成酶ｍＲＮＡ水平的改变。结果 糖尿病大鼠肾脏皮质ＮＯＳ活性及ｉＮＯＳ ｍＲＮＡ水平明显高于正常对照组（Ｐ〈０．０５）,然而ＮＯ含量却反而下降（Ｐ〈０．０５）。结论 糖尿病大鼠肾脏一氧化氮合成障碍,灭活加速     

Renal hemodynamics and urinary concentrating capacity in protein deprivation: role of antidiuretic hormone.

The role of antidiuretic hormone (ADH) in the renal concentration defect and hemodynamic changes in protein malnutrition was evaluated in rats with diabetes insipidus (DI) after 2 weeks of low protein feeding. Free water reabsorptive capacity (TcH2O), glomerular filtration rate (GFR), and renal plasma flow (RPF) were measured in the protein deprived rats and in DI rats fed a normal protein diet. The effect of urea supplementation of the low protein diet on renal concentrating capacity was also evaluated. In addition, the renal hemodynamic response to acute administration of ADH was measured and correlated with changes in plasma renin concentration and renal renin content (RRC). Protein deprivation in DI rats resulted in reduced urine osmolality and urea excretion, differences which were reversed by urea supplementation. Protein deprivation did not affect free water reabsorptive capacity but did reduce GFR and RPF. Acute ADH administration significantly increased GFR and RPF in protein-deprived rats; these changes were associated with a reduction in RRC and release. These results suggest that dietary protein restriction does not directly affect the tubular capacity to generate and reabsorb free water. The hemodynamic changes seen in protein deprivation are not mediated by ADH and may be secondary to increased intrarenal angiotensin II.     

Renal hemodynamics in experimentally galactosemic dogs and diabetic dogs

To examine the association between renal hemodynamic abnormalities and the development of diabetic kidney disease, glomerular filtration rate (GFR) and renal plasma flow (RPF) have been determined in dogs with alloxan-induced diabetes or experimental galactosemia of 1 to 5 years duration. GFR and RPF were significantly greater than normal in insulin-deficient diabetic dogs. GFR was also significantly greater than normal in the galactosemic animals, and RPF tended to be elevated even though GFR and RPF were measured at time of day when plasma galactose is no longer elevated. GFR and effective RPF (eRPF) were found to increase in normal animals upon acute elevation of blood galactose or glucose concentration. Thus, GFR is supranormal in experimental galactosemia, as well as in diabetes, although galactosemia has been shown not to cause nephromegaly, mesangial expansion, or glomerular obliteration, which are typical of diabetes. Administration of an aldose reductase inhibitor (Sorbinil) at dosages sufficient to significantly reduce erythrocyte polyol concentration did not significantly influence GFR or RPF in diabetic or galactosemic dogs.     

Determinants of the renal response to ACE inhibition in patients with congestive heart failure.

The objective of the present study was to determine whether pretreatment neurohormonal and renal hemodynamic parameters predict the change in renal function with the administration of quinapril, a new angiotensin-converting enzyme (ACE) inhibitor. Twenty patients with New York Heart Association (NYHA) class III and IV heart failure were evaluated. Following pretreatment determination of renal function and plasma neurohormones, patients were treated daily with 10 mg of quinapril. Measurements of glomerular filtration rate (GFR) and renal plasma flow (RPF) were repeated after 7 weeks to assess changes in function (delta GFR and delta RPF). Mean GFR increased from 49 +/- 6 to 56 +/- 7 ml/min/1.73 m2 (p = 0.10), but decreased in five patients. Mean RPF increased from 235 +/- 23 to 252 +/- 23 ml/min/1.73 m2 (p = 0.08), but decreased in five patients. There was no relation between delta GFR and baseline determinations of GFR, RPF, plasma renin activity, plasma angiotensin II, or serum Na. Only a high filtration fraction (GFR/RPF) predicted a decreased GFR (r = 0.61, p less than 0.005). In contrast, no baseline renal hemodynamic parameter correlated with delta RPF. We conclude that poor renal function does not increase the risk of renal deterioration with quinapril. However, dependence of renal function upon the renin-angiotensin system may be predicted by a high filtration fraction.     

Vascular endothelial growth factor in diabetes induced early retinal abnormalities

Increased vascular permeability and blood flow alterations are characteristic features of diabetic retinal microangiopathy. The present study investigated vascular endothelial growth factor (VEGF) and its interactions with endothelin (ET) 1 and 3, endothelial, and inducible nitric oxide synthase (eNOS, iNOS) in mediating diabetes induced retinal vascular dysfunction. Male Sprague Dawley rats with streptozotocin (STZ) induced diabetes, with or without VEGF receptor signal inhibitor SU5416 treatment (high or low dose) were investigated after 4 weeks of follow-up. Colour Doppler ultrasound of the ophthalmic/central retinal artery, retinal tissue analysis with competitive RT-PCR and microvascular permeability were studied. Diabetes caused increased microvascular permeability along with increased VEGF mRNA expression. Increased vascular permeability was prevented by SU5416 treatment. Diabetic animals showed higher resistivity index (RI), indicative of vasoconstriction with increased ET-1 and ET-3 mRNA expression, whereas eNOS and iNOS mRNA expressions were un-affected. SU5416 treatment corrected increased RI via increased iNOS in spite of increased ET-1, ET-3 and VEGF mRNA expression. Cell culture (HUVEC) studies indicate that in part, an SU5416 induced iNOS upregulation may be mediated though a MAP kinase signalling pathway. The present data suggest VEGF is important in mediating both vasoconstriction and permeability in the retina in early diabetes.     

Influence of irbesartan and enalapril on changes of renal function associated with the established phase of l-NAME hypertension.

OBJECTIVE : Reversibility of the systemic and renal alterations induced by N(omega)-nitro-L-arginine-methyl ester(L-NAME) was assessed by treatment with irbesartan and enalapril (30 and 10 mg/kg per 24 h, respectively) alone or in combination. DESIGN : L-NAME (20 mg/kg per 24 h) was given to rats for 6 weeks and treatments were administered during the last 2 weeks. Glomerular filtration rate and renal plasma flow [GFR and RPF per g of kidney weight (KW)] were determined using the clearance technique. RESULTS : Arterial pressure was similarly reduced by treatments. GFR was lower in L-NAME-treated rats than in controls (552 +/- 52 versus 1106 +/- 78 microl/min per g KW), whereas RPF was reduced to a larger extent, thus resulting in an increase in filtration fraction. GFR was normalized by irbesartan but not enalapril or the combination (1042 +/- 50, 790 +/- 79 and 725 +/- 38 microl/min per g KW, respectively). RPF returned to normal and filtration fraction fell markedly with the combination. All treatments reduced the lesions of preglomerular vessels and reversed L-NAME-induced albuminuria and cardiovascular hypertrophy. At a dose of 3 mg/kg per 24 h, irbesartan only reduced the lesions of the afferent arteriole. CONCLUSIONS : Through its effects on AT1 receptors, angiotensin II may play an important role in the maintenance of L-NAME hypertension and associated alterations. The lower GFR and filtration fraction observed with enalapril in the presence of irbesartan suggests the intervention of non-angiotensin II-mediated mechanism, and at the postglomerular level, in the effect of angiotensin-converting enzyme (ACE) inhibitors.     

下丘脑AVP及肾脏皮质V1a受体mRVA在肝硬化大鼠中的表达及黄芪的作用

目的观察肝硬化大鼠ＡＶＰ系统的变化及中药黄芪的治疗作用。方法采用斑点杂交和半定量ＲＴ－ＰＣＲ法检测胆总管结扎２周所致肝硬化大鼠下丘脑ＡＶＰ及其肾脏皮质Ｖ１ａ受体基因表达。结果肝硬化大鼠下丘脑ＡＶＰｍＲＮＡ水平明显升高，肾脏皮质Ｖ１ａ受体ｍＲＮＡ表达下调，可能与非渗透性因素有关。应用黄芪可使模型鼠ＡＶＰ高表达下降，并促使肾脏皮质Ｖ１ａ受体基因表达进一步降低。结论肝硬化大鼠存在ＡＶＰ系统异常，黄芪具有一定改善作用。