高效毛细管电泳测定血管紧张素转化酶抑制剂captopril的活性

目的建立高效毛细管电泳测定血管紧张素转化酶抑制剂captopril抑制活性的方法。方法用紫外分光光度计确定了马尿酸的特征吸收波长为228 nm。高效毛细管电泳的条件：熔融石英毛细柱，电泳缓冲液为pH 8.3的50 mmol·L^-1磷酸缓冲液，进样压力4.8 kPa，进样时间3 s，分离电压20 kV，检测波长228 nm。结果在7 min内使反应物和生成物完全分离，标定了captopril的IC₅₀值为0.019　μmol·L^-1，经过酶反应动力学判断captopril为竞争性抑制剂。结论该方法准确、简便、快速，可用于captopril抑制活性的分析。     

The potential actions of angiotensin-converting enzyme II (ACE2) activator diminazene aceturate (DIZE) in various diseases

The renin angiotensin system (RAS) regulates fluid balance, blood pressure and maintains vascular tone. The potent vasoconstrictor angiotensin II (Ang II) produced by angiotensin-converting enzyme (ACE) comprises the classical RAS. The non-classical RAS involves the conversion of Ang II via ACE2 into the vasodilator Ang (1-7) to counterbalance the effects of Ang II. Furthermore, ACE2 converts AngA into another vasodilator named alamandine. The over activation of the classical RAS (increased vasoconstriction) and depletion of the non-classical RAS (decreased vasodilation) results in vascular dysfunction. Vascular dysfunction is the leading cause of atherosclerosis and cardiovascular disease (CVD). Additionally, local RAS is expressed in various tissues and regulates cellular functions. RAS dysregulation is involved in other several diseases such as inflammation, renal dysfunction and even cancer growth. An approach in restoring vascular dysfunction and other pathological diseases is to either increase the activity of ACE2 or reduce the effect of the classical RAS by counterbalancing Ang II effects. The antitrypanosomal agent, diminazene aceturate (DIZE), is one approach in activating ACE2. DIZE has been shown to exert beneficial effects in CVD experimental models of hypertension, myocardial infarction, type 1 diabetes and atherosclerosis. Thus, this review focuses on DIZE and its effect in several tissues such as blood vessels, cardiac, renal, immune and cancer cells.     

血管紧张素转换酶2与心血管疾病

肾素-血管紧张素系统(RAS)是与心血管系统疾病密切相关的一个重要环节。RAS调整着心脏、血管和肾脏的生理功能的平衡,对机体血压、血流以及内环境的调节具有重要意义。作为RAS系统中又一关键调节因子的血管紧张素转换酶2(ACE2)近年来备受关注,ACE2与心血管系统相关疾病的研究也有了突破性的进展,为心血管疾病的治疗提供了新的途径;现将缺血性心肌病、原发性高血压、心率失常等疾病与ACE2基因表达的相关内容作一综述。     

Pharmacological profiles of two new angiotensin-converting enzyme (ACE) inhibitors: CGS 13945 and CGS 13934

CGS 13945 and CGS 13934 are two nonthiol ACE inhibitors having novel chemical structures. CGS 13945 is a monoester derivative of the free dicarboxylic acid CGS 13934. Based on studies from in vitro inhibition of ACE and in vivo inhibition of angiotensin I pressor responses, CGS 13945 must be hydrolyzed to CGS 13934 to express its optimal biological activity. Studies with rats reveal that CGS 13945 and CGS 13934 are orally effective inhibitors of ACE. Both inhibitors have a longer duration of action and are somewhat less effective than captopril. After oral administration, the bioavailability of the monoester CGS 13945 is greater than that of the free dicarboxylic acid CGS 13934. In the dog, CGS 13934 (i.v.) effectively inhibits angiotensin I pressor responses, but the esterified compound (CGS 13945) has only weak activity. This difference is presumably due to limited hydrolytic capacity of endogenous plasma esterase(s) in this species. However, both CGS 13945 and CGS 13934 potentiate the vasodepressor responses to bradykinin without affecting angiotensin II pressor responses.     

Antihypertensive assessment of two new angiotensin-converting enzyme (ACE) inhibitors: CGS 13945 and CGS 13934

CGS 13945 (1-(4-(ethoxycarbonyl)-2,4-dimethyl-2R,4R-butyryl)-2,3-dihydro-2S-indole-2-carboxylic acid) and CGS 13934 (its dicarboxylic acid derivative) are nonthiol angiotensin-converting enzyme (ACE) inhibitors which have antihypertensive properties. Acute administration of CGS 13945 lowers systolic pressure in spontaneously hypertensive rats (SHR) and sodium depletion enhances the blood pressure reduction; the acute antihypertensive effects of CGS 13934 are minimal. Acute administration of CGS 13945 or CGS 13934 also elevates plasma renin activity, especially in sodium-depleted SHR. CGS 13945 reduces systolic blood pressure of SHR in a dose-dependent manner following oral administration on each of 4 consecutive days, whereas the antihypertensive effect of CGS 13934 is not apparent until the third day of drug administration. After 3 consecutive daily doses, 30 mg/kg (PO) of CGS 13945, CGS 13934 or captopril produce equal antihypertensive effects. CGS 13945 also reduces systolic blood pressure of sodium-depleted normotensive rats. Daily oral administration of CGS 13945 to either sodium-replete or -deplete perinephritic hypertensive dogs does not appreciably affect mean arterial pressure. Results suggest that CGS 13945 must be endogenously de-esterified to the free acid form for endowment of optimal biological activity to inhibit the ACE. While the rat is apparently capable of such hydrolysis, the dog's capacity for endogenous hydrolysis appears to be quite limited.     

Angiotensin I-converting enzyme (ACE) inhibition and antihypertensive effects of EU-5476, a new,potent, and long-acting ACE inhibitor

EU-5476 is a new, orally active angiotensin I-converting enzyme (ACE) inhibitor. In vitro, EU-5476 produced a concentration-dependent inhibition of ACE purified from rabbit lung (IC₅₀ = 0.084 μ). Inhibition showed complex kinetics and was reversible as determined by equilibrium dialysis. EU-5476 inhibited plasma ACE in mice (93.8% inhibition at 5 μmol/kg) and produced dose-dependent inhibition of plasma ACE in dogs (ID₅₀ = 2.52 μmol/kg) after oral administration. In acute aortic coarctate hypertensive rats, EU-5476 administered orally produced dose-dependent decreases in blood pressure (ED₃₀ = 0.53 μmol/kg). The magnitude and duration of blood pressure reduction in hypertensive rats were similar to those of plasma ACE inhibition in dogs, suggesting that plasma ACE inhibition per se is one of the mechanisms of the antipertensive action of EU-5476. Comparative studies showed that EU-5476, like enalapril, was more potent and longer acting than captopril in producing plasma ACE inhibition and an antihypertensive response. EU-5476 is a potent and long-acting, orally effective ACE inhibitor potentially useful in the treatment of hypertension.     

Mechanisms mediating the cardioprotective effects of rapamycin in ischaemia-reperfusion injury

1. In the present study, the temporal and concentration-dependent cardioprotective effects of rapamycin against ischaemia-reperfusion (I/R) injury, as well as the underlying mechanisms, were investigated. 2. Rat Langendorff-perfused isolated hearts were exposed to 40 min global ischaemia followed by 120 min reperfusion. Hearts were perfused with different concentrations of rapamycin before and after ischaemia. Myocardial injury was assessed in terms of infarct size and the release of lactate dehydrogenase (LDH) and creatine kinase (CK). The phosphorylation of Akt, extracellular signal-regulated kinase (ERK) 1/2 and endothelial nitric oxide synthase (eNOS) was determined at the end of reperfusion. 3. When administered prior to ischaemia, 25, 50 and 100 nmol/L rapamycin significantly reduced infarct size compared with control (40.1 ± 1.5, 26.3 ± 4.1 and 21.2 ± 3.4 vs 52.5 ± 4.5%, respectively) without affecting the recovery of ventricular function. No reduction in infarct size was observed when 50 nmol/L rapamycin was administered 10 or 120 min into the reperfusion period. 4. Rapamycin (50 nmol/L) enhanced the phosphorylation of Akt kinase but did not affect the phosphorylation of ERK1/2 or eNOS at the end of reperfusion. The cardioprotective effect of rapamycin was blocked by the phosphatidylinositol 3-kinase (Akt) inhibitor LY294002 (15 nmol/L). 5. In conclusion, rapamycin mediates cardioprotection prior to ischaemia and after reperfusion. This protection may involve activation of the phosphatidylinositol 3-kinase pathway.     

Differential Recognition of ACE Inhibitors in Xenopus Laevis Oocytes Expressing Rat PEPT1 and PEPT2

Purpose. To examine the mechanism of inhibition of glycylsarcosine(GlySar) transport by quinapril and enalapril, and whether or notangiotensin converting enzyme (ACE) inhibitors are transported by PEPT2as well as by PEPT1. Methods. Xenopus laevis oocytes were cRNA-injected with rat PEPT1or PEPT2 and the transport kinetics of radiolabeled GlySar were studiedin the absence and presence of quinapril and enalapril. Thetwo-microelectrode voltage-clamp technique was also performed to probe theelectrogenic uptake of captopril, quinapril and enalapril. Results. Kinetic analyses demonstrated that quinapril inhibited theuptake of GlySar in a noncompetitive manner in Xenopus oocytesinjected with PEPT1 or PEPT2 (Ki = 0.8 or 0.4 mM, respectively).In contrast, a competitive interaction was observed between GlySarand enalapril (Ki = 10.8 mM for PEPT1 or 4.3 mM for PEPT2).Most significantly, captopril and enalapril, but not quinapril, inducedinwardly-directed currents in both PEPT1- and PEPT2-expressedoocytes. Conclusions. These results are unique in providing direct evidence forthe substrate recognition and transport of some ACE inhibitors by thehigh- and low-affinity oligopeptide transporters. Our findings point todifferences between PEPT1 and PEPT2 in their affinity to, rather thanin their specificity for, ACE inhibitors.     

Antioxidant activity and protective effects of cocoa and kola nut mistletoe (Globimetula cupulata) against ischemia/reperfusion injury in Langendorff-perfused rat hearts

Protection against cardiomyocyte damage following ischemia/reperfusion (I/R) injury is highly desirable in patients with ischemic heart disease. Hydromethanol extracts of Globimetula cupulata (mistletoe) growing on cocoa (CGCE) and kola nut (KGCE) trees were assessed for antioxidant content and cardioprotective potential against I/R. Graded concentrations (1–50 μg/mL) of CGCE or KGCE were tested on Langendorff-perfused rat hearts to evaluate the effects on the flow rate, heart rate, and force of cardiac contraction, while another set of hearts were subjected to biochemical analyses. Both extracts showed good antioxidant content and activity, but KGCE (EC₅₀: 24.8±1.8 μg/mL) showed higher hydroxyl radical scavenging activity than CGCE (70.2±4.5 μg/mL). Both extracts at 3 μg/mL reversed (p < 0.001) membrane peroxidation and the significant decrease in nitrite level, coronary flow rate, and superoxide dismutase and catalase activity caused by the I/R cycle. It is concluded that G. cupulata protects against ischemia–reperfusion injury in rat hearts via augmenting endogenous antioxidants and significant restoration of altered hemodynamic parameters.     

Induction of angiotensin I-converting enzyme in rat lung with captopril (SQ 14225)

Angiotensin I-converting enzyme (ACE, EC 3.4.15.1.) was measured in serum and in pulmonary plasma membranes of 140 spontaneously hypertensive rats (SHR, Okamoto Aoki strain), divided into 4 groups, and treated with SQ 14225 (Captopril®), 0.2 mg · ml^?1 in drinking water, for 0–24 weeks. Serum ACE activity increased 2.5–3 fold after 12–24 weeks of SQ 14225 treatment, paralleled by an increasep of ACE concetration in purified pulmonary plasma membranes (25–52%), and in ACE concentration upon solubilization with Triton X-100 from such plasma membranes (96–120%). We conclude that the ACE inhibitor, SQ 14225, causesp marked induction of pulmonary ACE biosynthesis. High serum ACE activity probably reflects increased total biosynthesis of the enzyme.     

Relative Lipophilicities and Structural-Pharmacological Considerations of Various Angiotensin-Converting Enzyme (ACE) Inhibitors

Lipophilicities of seven structurally diverse angiotensin-converting enzyme (ACE) inhibitors, viz., captopril, zofenoprilat, enalaprilat, ramiprilat, lisinopril, fosinoprilat, and ceronapril (SQ29852), were compared by determining their octanol-water distribution coefficients (D) under physiological pH conditions. The distribution coefficients of zofenopril, enalapril, ramipril and fosinopril, which are the prodrug forms of zofenoprilat, enalaprilat, ramiprilat, and fosinoprilat, respectively, were also determined. Attempts were made to correlate lipophilicities with the reported data for oral absorption, protein binding, ACE inhibitory activity, propensity for biliary excretion, and penetration across the blood-brain barrier for these therapeutic entities. Better absorption of prodrugs compared to their respective active forms is in agreement with their greater lipophilicities. Captopril, lisinopril, and ceronapril are orally well absorbed despite their low lipophilicities, suggesting involvement of other factors such as a carrier-mediated transport process. Of all the compounds studied, the two most lipophilic ACE inhibitors, fosinoprilat and zofenoprilat, exhibit a rank-order correlation with respect to biliary excretion. This may explain the dual routes of elimination (renal and hepatic) observed with fosinoprilat in humans. The more lipophilic compounds also exhibit higher protein binding. Both the lipophilicity and a carrier-mediated process may be involved in penetration of some of these drugs into brain. For structurally similar compounds, in vitro ACE inhibitory activity increased with the increase in lipophilicity. However, no clear correlation between lipophilicity and ACE inhibitory activity emerged when different types of inhibitors are compared, possibly because their interactions with enzymes are primarily ionic in nature.     

Comparison of cardioprotective effects of mibefradil and ramipril in stroke-prone spontaneously hypertensive rats

INTRODUCTION Acutemyocardial infarction(MI), particularlylargeand transmural infarctions, can result in complex alter-ations of cardiac architecture involving both the inf-used in the treatment of clinical myocardial ischemia. GmbH, Soest, Germany) and tap water. The investiga-However, their therapeutic properties in myocardial in- tion was under the Guide for the Care and Use of Labo-farction-induced heart failure is not clearly defined. rat…     

Pretreatment with ramiprilat induces cardioprotection against free radical injury in guinea-pig isolated heart: involvement of bradykinin, protein kinase C and prostaglandins

1. Pretreatment with ramiprilat, an angiotensin-converting enzyme (ACE) inhibitor, induced cardioprotection and its possible mechanism of action was investigated in guinea-pig Langendorff perfused heart. 2. Superoxide anion (*O2-), produced by hypoxanthine and xanthine oxidase, and the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical were used for triggering free radical injury in cardiac tissue. 3. 1,1-Diphenyl-2-picryl-hydrazyl and *O2- significantly reduced left ventricular developed pressure (LVDP), +/-dP/dt(max), heart rate and coronary flow. Left ventricular end-diastolic pressure (LVEDP) was elevated and lactate dehydrogenase (LDH) leakage and the formation of thiobarbituric acid-reactive substances (TBARS) formation were significantly increased. 4. Pretreatment with ramiprilat induced cardioprotection against DPPH and *O2- free radical injury. Cardiac functions (LVDP, LVEDP and +/-dP/dt(max)) were significantly improved. Both LDH and TBARS were reduced. 5. HOE 140 (a selective bradykinin B2 receptor antagonist), calphostin C (a protein kinase C (PKC) inhibitor) and indomethacin (a cyclo-oxygenase inhibitor) all abolished the cardiac protective effect of ramiprilat. However, N(G)-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, had no effect. 6. In conclusion, ramiprilat pretreatment induces cardioprotection against either DPPH or *O2- free radical injury. The protective effect depends on activation of B2 receptors and PKC. Prostaglandin synthesis is also involved.     

临床药师在冠心病监护病区促进血管紧张素转换酶抑制剂合理使用的成效

目的 提高血管紧张素转换酶抑制剂（ACEI）的使用合理性。方法 临床药师查阅2012年5月—2013年5月本院冠心病监护病区（CCU）所有病例,参照ACEI专家共识、指南以及药品说明书的标准对ACEI的使用合理性进行分析,但不予任何干预。2013年6月—2015年5月,临床药师参照同样标准,对ACEI的使用合理性进行干预。结果 对比干预前后的数据发现,ACEI使用百分比从80.1%提高至98.9%,ACEI起始剂量偏大的百分比由21.4%下降至0.9%,ACEI剂量不足的百分比从4.7%降至0.5%,差异均有统计学意义。结论 临床药师在促进ACEI的使用合理性方面可起主导作用。     

Regulation of uterine smooth muscle bradykinin receptors by bradykinin levels and angiotensin converting enzyme inhibitor in the rat

1. Bradykinin infusion (0.1 microgram/min i.v.) decreased the number of uterine bradykinin receptors by 20% at Day 2. Bradykinin receptors returned to control levels at Day 7. 2. Captopril infusion (1.7 micrograms/min i.v.) induced prolonged decreases in the number of uterine bradykinin receptors of 15% at Day 2 and of 13% at Day 7, respectively. 3. The number of uterine bradykinin receptors was increased in two-kidney, one clip hypertensive rats by 19%. 4. These results suggest that endogenous bradykinin participates in the regulation of uterine bradykinin receptors. 5. Decreased uterine bradykinin receptors induced by captopril might reflect increased endogenous bradykinin.     

血管紧张素转换酶基因多态性与原发性高血压血栓前状态的关系

目的　探讨血管紧张素转换酶 (ACE)基因I/D多态性与原发性高血压 (EH)及高血压血栓前状态 (PTS)的关系。方法　PCR检测 6 1例原发性高血压病人和正常对照组 2 8例的ACE基因I/D多态性 ;发色底物法测t PA、PAI 1活性 ,酶联免疫吸附双抗夹心法 (ELISA)测vWF含量。结果　高血压组DD基因型频率显著高于对照组 (P <0 0 5 ) ,但D等位基因频率分布在高血压组和正常组之间差异无显著意义 (P >0 0 5 )。高血压组t PA活性降低 ,PAI 1活性、vWF含量升高 (P均 <0 0 0 1)。高血压组DD型t P活性明显低于ID、II型 (P <0 0 0 1) ,而ID、II型之间差异无显著意义 (P >0 0 5 ) ,DD型PAI 1活性明显高于ID、II型(P <0 0 0 1) ,而ID、II型之间差异无显著意义 (P >0 0 5 ) ,vWF在DD、ID、II型三者之间差异无显著意义 (P>0 0 5 )。结论　DD型是原发性高血压发病的危险因素。原发性高血压存在血栓前状态。t PA、PAI 1的变化与血管紧张素转换酶基因I/D多态性有关 ,DD基因型可引起血栓前状态。     

Potentiation of the pro-inflammatory effects of bradykinin by inhibition of angiotensin-converting enzyme and aminopeptidase P in rat paws

The influence of some peptidase inhibitors on oedema and plasma extravasation induced by bradykinin and carrageenan in rat paw was evaluated. Bradykinin-induced oedema in normal rats was increased by o-phenanthroline (3.10^–2 M), by captopril (10^–6 M to 10^–4 M), by lisinopril (10^–6 M to 10^–4 M), or by lisinopril (10^–5 M) in combination with apstatin (8.10^–5 M or 1.4 10^–4 M). It was not modified by phosphoramidon (10^–6 M to 10^–5 M) and by diprotin A (10^–3 M). It was increased by mergepta at high concentrations (2.10^–4 M). Mergepta did not increase the potentiating effect of captopril. Carrageenan-oedema in normal rats was increased by captopril (10^–5 M), lisinopril (10^–5 M) and apstatin (1.4 10 M). It was not modified by mergepta (10^–4 M), phosphoramidon (10^–5 M) and diprotin A (10^–3 M). Des-Argl-bradykinin and Des-Arg⁹-bradykinin have low oedema-promoting effects. Captopril (10^–5 M) increased the effects of bradykinin but not those of carrageenan in kininogen-deficient Brown Norway rats. Angiotensin-converting enzyme and amino-peptidase P appear to be main kinin-inactivating enzymes in rat paws. Carboxypeptidase N, neutral endopeptidase 24.11 and dipeptidyl(amino)peptidase IV do not play a significant role in this inactivation.     

Metabolic effects of long-term angiotensin-converting enzyme inhibition with fosinopril in patients with essential hypertension: relationship to angiotensin-converting enzyme inhibition

Fifty patients with mild to moderate essential hypertension were randomized to receive either 20 mg fosinopril daily for 16 weeks or placebo for 4 weeks followed by 12 weeks of 50 mg atenolol daily. Prior to these 16 weeks there was a placebo wash-out period of 2–6 weeks. Blood pressure measurements, euglycaemic, hyperinsulinaemic glucose clamps, and intravenous glucose tolerance tests (IVGTT) were performed at baseline and after 4 and 16 weeks. Blood lipid status was evaluated at baseline and 16 weeks.The insulin sensitivity index (M/I) increased by 12% during the prolonged placebo period, and subsequently decreased by 12% during treatment with atenolol in that group. A post-hoc analysis of covariance indicated that the increase in insulin sensitivity during the initial 4 weeks may have been due to carry over effects from previous anti-hypertensive treatment. Fosinopril increased glucose disappearance during IVGTT at 4 and 16 weeks (k values 1.46 and 1.33 vs 1.10 at baseline) but had no effect on insulin sensitivity. The change in insulin sensitivity and serum triglycerides during treatment with fosinopril was related to angiotensin-converting enzyme inhibition in serum.In conclusion, carry-over effects from previous anti-hypertensive medication were indicated in this study, probably because of an insufficient wash-out period in many patients. Therefore, 4 weeks of placebo wash-out in all patients is advisable in this kind of investigation.     

新疆发酵乳酪乳清体外ACE抑制和抗氧化活性研究

目的:研究新疆传统发酵乳酪乳清(简称TFCW)超滤提取物对血管紧张素转换酶(ACE)的抑制活性、抗氧化活性。方法:以体外活性ACE抑制率和DPPH.,.OH,O2-.的清除率为指标,检测TFCW中相对分子质量范围分别在30～10 kDa,10～5 kDa和5 kDa以下超滤提取物的ACE抑制活性、抗氧化活性。用Sephadex G-15柱层析对5 kDa以下肽段进行分离,并对其分离产物进行检测。结果:相对分子质量5 kDa以下的肽段,ACE抑制作用和抗氧化活性最高。用Sephadex G-15对其进行分离,得到5个组分。其中组分4(相对分子质量分布在1071～724 Da)对ACE抑制率高达56.45%;组分5(相对分子质量分布在645～500Da)对自由基DPPH.,.OH,O2-.的清除率分别是59.06%,62.06%,29.51%。结论:TFCW中的多肽具有较强的体外ACE抑制活性和抗氧化活性。