Quinapril treatment curtails decline of global longitudinal strain and mechanical function in hypertensive rats

BACKGROUND

Left ventricular (LV) global longitudinal strain (GLS) has been proposed as an early imaging biomarker of cardiac mechanical dysfunction.

OBJECTIVE

To assess the impact of angiotensin-converting enzyme (ACE) inhibitor treatment of hypertensive heart disease on LV GLS and mechanical function.

METHODS

The spontaneously hypertensive rat (SHR) model of hypertensive heart disease ( n  = 38) was studied. A subset of SHRs received quinapril (TSHR, n  = 16) from 3 months (mo). Wistar Kyoto rats (WKY, n  = 13) were used as controls. Tagged cardiac MRI was performed using a 4.7 T Varian preclinical scanner.

RESULTS

The SHRs had significantly lower LV ejection fraction (EF) than the WKYs at 3 mo (53.0 ± 1.7% vs. 69.6 ± 2.1%, P  < 0.05), 14 mo (57.0 ± 2.5% vs. 74.4 ± 2.9%, P  < 0.05) and 24 mo (50.1 ± 2.4% vs. 67.0 ± 2.0%, P  < 0.01). At 24 mo, ACE inhibitor treatment was associated with significantly greater LV EF in TSHRs compared to untreated SHRs (64.2 ± 3.4% vs. 50.1 ± 2.4%, P  < 0.01). Peak GLS magnitude was significantly lower in SHRs compared with WKYs at 14 months (7.5% ± 0.4% vs. 9.9 ± 0.8%, P  < 0.05). At 24 months, Peak GLS magnitude was significantly lower in SHRs compared with both WKYs (6.5 ± 0.4% vs. 9.7 ± 1.0%, P  < 0.01) and TSHRs (6.5 ± 0.4% vs. 9.6 ± 0.6%, P  < 0.05).

CONCLUSIONS

ACE inhibitor treatment curtails the decline in global longitudinal strain in hypertensive rats, with the treatment group exhibiting significantly greater LV EF and GLS magnitude at 24 mo compared with untreated SHRs.

Efficacy of Administration of an Angiotensin Converting Enzyme Inhibitor for Two Years on Autonomic and Peripheral Neuropathy in Patients with Diabetes Mellitus

Aim. To evaluate the effect of quinapril on diabetic cardiovascular autonomic neuropathy (CAN) and peripheral neuropathy (DPN). Patients and Methods. Sixty-three consecutive patients with diabetes mellitus [43% males, 27 with type 1 DM, mean age 52 years (range 22-65)], definite DCAN [abnormal results in 2 cardiovascular autonomic reflex tests (CARTs)], and DPN were randomized to quinapril 20 mg/day (group A, n = 31) or placebo (group B, n = 32) for 2 years. Patients with hypertension or coronary heart disease were excluded. To detect DPN and DCAN, the Michigan Neuropathy Screening Instrument Questionnaire and Examination (MNSIQ and MNSIE), measurement of vibration perception threshold with biothesiometer (BIO), and CARTs [R-R variation during deep breathing [assessed by expiration/inspiration ratio (E/I), mean circular resultant (MCR), and standard deviation (SD)], Valsalva maneuver (Vals), 30 : 15 ratio, and orthostatic hypotension (OH)] were used. Results. In group A, E/I, MCR, and SD increased (p for all comparisons < 0.05). Other indices (Vals, 30 : 15, OH, MNSIQ, MNSIE, and BIO) did not change. In group B, all CART indices deteriorated, except Vals, which did not change. MNSIQ, MNSIE, and BIO did not change. Conclusions. Treatment with quinapril improves DCAN (mainly parasympathetic dysfunction). Improved autonomic balance may improve the long-term outcome of diabetic patients.

Vascular effects of quinapril completely depend on ACE insertion/deletion polymorphism

Introduction

The angiotensin-converting enzyme (ACE) DD-genotype is associated with increased plasma and myocardial ACE-activity. The influence of the ACE insertion/deletion (I/D) polymorphism on the effects of ACE-inhibition on vascular responses has not been previously described.

Materials and methods

In the randomised, double-blind QUinapril On Vascular ACE and Determinants of Ischemia Study (QUO VADIS), 149 patients undergoing coronary bypass surgery were randomised to receive either the ACE inhibitor, quinapril, or placebo. In 82 patients, we obtained ACE-genotype, and measured vascular responses to angiotensin II (Ang II) in left internal mammary arteries.

Results

In the placebo group, the mean maximal vasoconstriction to Ang II was significantly lower in patients with the DD-genotype than in those with the ID/II genotype (36.2±5.11% [n=13] vs. 55.6±4.57% [n=25]; p=0.01). In the quinapril group, the mean maximal vasoconstriction to Ang II was similar [n=8] vs. 57.7±4.07% [n=35]; p=0.85). between DD- and ID/II-genotype (59.6±9.19%

Conclusions

DD-genotype patients showed decreased vascular responses to Ang II but treatment with quinapril completely restored the decreased vascular response in DD-genotype patients to the same level as II/ID-genotype patients, while no effect of quinapril was demonstrated in the II/ID-genotype patients.

The effects of quinapril and atorvastatin on the responsiveness to sildenafil in men with erectile dysfunction

Phosphodiesterase-5 (PDE-5) inhibitors are an effective therapy for the majority of men with erectile dysfunction (ED). However, many men with ED still report a suboptimal or partial response even after an adequate trial of oral PDE-5 therapy. Since ED is associated with impaired vascular function and both atorvastatin and quinapril have been previously shown to improve vascular function, we examined the effects of adjunctive treatment with these medications in men with vasculogenic ED who were suboptimal responders to 100 mg of sildenafil. Men with ED and suboptimal response to sildenafil were randomly assigned to 3 months of treatment with atorvastatin 40 mg ( n = 12), quinapril 10 mg ( n = 10), or placebo ( n = 13), along with continued adjunctive sildenafil use. Measured variables included: International Index of Erectile Function (IIEF) questionnaire, brachial artery flow-mediated dilation (FMD), endothelium-independent dilation (EID) via nitroglycerin, penile Doppler blood flow, blood pressure (BP), lipids, and C-reactive protein (CRP). Compared to placebo, quinapril ( p < 0.01) significantly improved symptoms of ED as measured by the IIEF-5 questionnaire. There was a trend toward a significant improvement in IIEF-5 with atorvastatin. Similarly, quinapril significantly improved the IIEF ED Domain ( p < 0.05). Other peripheral and penile vascular parameters were unchanged with drug therapy as compared to placebo. In conclusion, treatment with quinapril, in combination with sildenafil, improved ED in men with suboptimal response to sildenafil alone. Atorvastatin demonstrated a trend toward improved ED in this group.

β-blocker Therapy is Not Associated with Reductions in Angina or Cardiovascular Events After Coronary Artery Bypass Graft Surgery: Insights from the IMAGINE Trial

Purpose

To evaluate whether β-blockers were associated with a reduction in cardiovascular events or angina after Coronary Artery Bypass Graft (CABG) surgery, in otherwise stable low-risk patients during a mid-term follow-up.

Methods

We performed a post-hoc analysis of the IMAGINE (Ischemia Management with Accupril post–bypass Graft via Inhibition of angiotensin coNverting Enzyme) trial, which tested the effect of Quinapril in 2553 hemodynamically stable patients with left ventricular ejection fraction (LVEF) >40 %, after scheduled CABG. The association between β-blocker therapy and the incidence of cardiovascular events (death, cardiac arrest, myocardial infarction, revascularizations, angina requiring hospitalization, stroke or hospitalization for heart failure) or angina that was documented to be due to underlying ischemia was tested with Cox regression and propensity adjusted analyses.

Results

In total, 1709 patients (76.5 %) were using a β-blocker. Patients had excellent control of risk factors; with mean systolic blood pressure being 121 ± 14 mmHg, mean LDL cholesterol of 2.8 mmol/l, 59 % of patients received statins and 92 % of patients received antiplatelet therapy. During a median follow-up of 33 months, β-blocker therapy was not associated with a reduction in cardiovascular events (hazard ratio 0.97; 95 % confidence interval 0.74–1.27), documented angina (hazard ratio 0.85; 95 % confidence interval 0.61–1.19) or any of the individual components of the combined endpoint. There were no relevant interactions for demographics, comorbidities or surgical characteristics. Propensity matched and time-dependent analyses revealed similar results.

Conclusions

β-blocker therapy after CABG is not associated with reductions in angina or cardiovascular events in low-risk patients with preserved LVEF, and may not be systematically indicated in such patients.

[INFLUENCE OF QUINAPRIL IN COMBINATION WITH ANGIOLINE ON THE CONNECTIVE TISSUE COMPONENTS IN THE RATS SERUM WITH EXPERIMENTAL HYPERTENSION]

One of the most active inhibitors angiotensin-converting enzyme is quinapril that has a high affinity for tissue ACE, improves endothelial vasodilation, has a wide therapeutic range and beneficient influence on heart rate. A new biological active compound with antioxidant action that has endothelioprotective, cardioprotective, antiischemic action is angiolin. In experimental arterial hypertension in the animals blood serum the activity of collagenase, the content of free and protein connecting fractions of hydroxyproline and indicators that reflect the metabolism of glycosaminoglycans have been increased. Angiolin increases the activity of collagenase free and protein connecting fractions of hydroxyproline comparing to control. Concentration glycosoaminoglycan (GAG) also exceeds the standard data. Quinapril has similar to angiolin action directed effect to the connective tissue components, though losing as proteinconecting of hydroxiproline action. Cooperative application quinapril with angioline most effectively influence the metabolic processes stabilization in experimental animals.

A vascular mechanism for high-sodium-induced insulin resistance in rats

AIMS/HYPOTHESIS

High sodium (HS) effects on hypertension are well established. Recent evidence implicates a relationship between HS intake and insulin resistance, even in the absence of hypertension. The aim of the current study was to determine whether loss of the vascular actions of insulin may be the driving factor linking HS intake to insulin resistance.

METHODS

Sprague Dawley rats were fed a control (0.31% wt/wt NaCl) or HS (8.00% wt/wt NaCl) diet for 4 weeks and subjected to euglycaemic-hyperinsulinaemic clamp (10 mU min(-1) kg(-1)) or constant-flow pump-perfused hindlimb studies following an overnight fast. A separate group of HS rats was given quinapril during the dietary intervention and subjected to euglycaemic-hyperinsulinaemic clamp as above.

RESULTS

HS intake had no effect on body weight or fat mass or on fasting glucose, insulin, endothelin-1 or NEFA concentrations. However, HS impaired whole body and skeletal muscle glucose uptake, in addition to a loss of insulin-stimulated microvascular recruitment. These effects were present despite enhanced insulin signalling (Akt) in both liver and skeletal muscle. Constant-flow pump-perfused hindlimb experiments revealed normal insulin-stimulated myocyte glucose uptake in HS-fed rats. Quinapril treatment restored insulin-mediated microvascular recruitment and muscle glucose uptake in vivo.

CONCLUSIONS/INTERPRETATION

HS-induced insulin resistance is driven by impaired microvascular responsiveness to insulin, and is not due to metabolic or signalling defects within myocytes or liver. These results imply that reducing sodium intake may be important not only for management of hypertension but also for insulin resistance, and highlight the vasculature as a potential therapeutic target in the prevention of insulin resistance.

Quinapril treatment abolishes diabetes-associated atherosclerosis in RAGE/apolipoprotein E double knockout mice

OBJECTIVE/RATIONALE

Both the renin-angiotensin system (RAS) and the receptor for advanced glycation end products (RAGE) potentiate diabetes-associated atherosclerosis (DAA). We assessed the effectiveness of concomitant RAS and RAGE inhibition on DAA.

METHODS

Diabetic (5 × 55 mg/kg streptozotocin daily) and non-diabetic male RAGE/apolipoprotein E double knockout (RAGE/apoE DKO) mice were treated with quinapril (30 mg/kg/day) for 20 weeks. At the end of the study aortic plaques were assessed.

RESULTS

Diabetic RAGE/apoE DKO showed significantly less plaque area than diabetic apoE KO mice. Plaque deposition was almost abolished in quinapril treated diabetic RAGE/apoE DKOs, with significant attenuation of vascular collagen deposition, nitrotyrosine staining, and reduced macrophage infiltration. Expression of the advanced glycation end product receptor 3 (galectin 3) was also significantly reduced.

CONCLUSION

Concomitant inhibition of RAS and RAGE signalling almost completely inhibited the development of experimental DAA. A dual therapeutic approach may be a superior strategy for the treatment of diabetic macrovascular disease..

Determination of losartan potassium, quinapril hydrochloride and hydrochlorothiazide in pharmaceutical preparations using derivative spectrophotometry and chromatographic-densitometric method

Two methods, spectrophotometric and chromatographic-densitometric ones, were developed for determination of losartan potassium, quinapril hydrochloride and hydrochlorothiazide in pharmaceutical preparations. Spectrophotometric method involved derivative spectrophotometry and zero order spectrophotometry. The measurements were carried out at lambda = 224.0 nm for quinapril, lambda = 261.0 nm for hydrochlorothiazide and lambda = 270.0 nm for losartan when the derivative spectrophotometry was applied and lambda = 317.0 nm when zero order spectrophotometry was applied for the determination of hydrochlorothiazide. In chromatographic-densitometric studies high performance thin layer chromatography (HPTLC) plates were used as stationary phase and a mixture of solvents n-butanol : acetic acid : water (15 : 5 : 1, v/v/v) as mobile phase. Under the established conditions good resolution of examined constituents was obtained. Retardation factor for quinapril hydrochloride was R(f) - 0.70, for losartan potassium R(f) - 0.85 and for hydrochlorothiazide R(f) - 0.78. The developed methods are characterized by high sensitivity and accuracy. For quantitative analysis, densitometric measurements were carried out at lambda = 218.0 nm for quinapril, lambda = 275.0 nm for hydrochlorothiazide and = 232.0 nm for losartan.

Alagebrium reduces glomerular fibrogenesis and inflammation beyond preventing RAGE activation in diabetic apolipoprotein E knockout mice

Advanced glycation end products (AGEs) are important mediators of diabetic nephropathy that act through the receptor for AGEs (RAGE), as well as other mechanisms, to promote renal inflammation and glomerulosclerosis. The relative contribution of RAGE-dependent and RAGE-independent signaling pathways has not been previously studied in vivo. In this study, diabetic RAGE apoE double-knockout (KO) mice with streptozotocin-induced diabetes were treated with the AGE inhibitor, alagebrium (1 mg/kg/day), or the ACE inhibitor, quinapril (30 mg/kg/day), for 20 weeks, and renal parameters were assessed. RAGE deletion attenuated mesangial expansion, glomerular matrix accumulation, and renal oxidative stress associated with 20 weeks of diabetes. By contrast, inflammation and AGE accumulation associated with diabetes was not prevented. However, treatment with alagebrium in diabetic RAGE apoE KO mice reduced renal AGE levels and further reduced glomerular matrix accumulation. In addition, even in the absence of RAGE expression, alagebrium attenuated cortical inflammation, as denoted by the reduced expression of monocyte chemoattractant protein-1, intracellular adhesion molecule-1, and the macrophage marker cluster of differentiation molecule 11b. These novel findings confirm the presence of important RAGE-independent as well as RAGE-dependent signaling pathways that may be activated in the kidney by AGEs. This has important implications for the design of optimal therapeutic strategies for the prevention of diabetic nephropathy.

[Advantages of quinapril therapy in patients with arterial hypertension and functional class III chronic heart failure with preserved left ventricular ejection fraction]

AIM

To determine advantages of therapy of functional class (FC) I-II chronic heart failure (CHF) with preserved left ventricular (LV) ejection fraction in patients with hypertensive disease (HD) with metoprolol succinate or quinapril and to assess their effect on regulatory-adaptive status.

METHODS

Two hundred patients with I-II FC CHF and LVEF >50% at the background of stage I-II hypertensive disease participated in this study. They were randomized into 2 groups. Group I comprised 104 patients (mean age 52.8+1.9 years) who were prescribed metoprolol succinate 87.7+/-7.6 mg/day. Patients of group 2 (n=96, mean age 55.0+/-1.4 years) were prescribed quinapril 21.0+55 mg/day. Examination at baseline and after 6 months of therapy included 6 min walk test, treadmillometry with assessment of maximal oxygen consumptiion (VO2max), echocardiography, 24 hour blood pressure monitoring, measurement of N-terminal precursor of brain natriuretic peptide (NT-proBNP); test of cardio-respiratory synchronism was used for objective qualitative determination of the state of the ,renin-angiotensin system.

RESULTS

Both drugs improved parameters of LV diastolic function, but only quinapril effectively changed LV structural geometric parameters and systolic function. Only treatment with quinapril was associated with improvement of RAS, elevation of tolerance to physical effort, and increased VO2max. Quinapril more substantially lowered level of NT-proBNP.

CONCLUSION

Quinapril has an advantage over metoprolol succinate in therapy of patients with FC I-II CHF and preserved LF EF at the background of stage I-II HD.

Delayed intervention with AGE inhibitors attenuates the progression of diabetes-accelerated atherosclerosis in diabetic apolipoprotein E knockout mice

AIMS/HYPOTHESIS

Formation of AGEs is increased in the diabetic milieu, which contributes to accelerated atherogenesis. We studied whether delayed treatment with AGE-inhibiting compounds, alagebrium chloride and pyridoxamine dihydrochloride, affected established atherosclerosis in experimental diabetes in comparison with the angiotensin-converting enzyme inhibitor, quinapril.

METHODS

Streptozotocin-induced diabetic male Apoe (-/-) mice (n = 24 per group) received, by oral gavage, from week 10 to 20 of diabetes: no treatment; alagebrium (1 mg kg(-1) day(-1)); pyridoxamine (1 g/l in drinking water); or quinapril (30 mg kg(-1) day(-1)). Atherosclerotic lesion area (en face analysis) was evaluated for all groups.

RESULTS

Delayed intervention with alagebrium decreased plaque area in the diabetic Apoe (-/-) mice compared with untreated mice (total plaque area: alagebrium 10.6 ± 1.6%, untreated, 15.1 ± 1.5%, p < 0.05). This anti-atherosclerotic effect was comparable with that achieved with quinapril (quinapril 8.4 ± 1.4%, vs untreated, p < 0.05). Pyridoxamine also attenuated plaque development in diabetic mice (5.7 ± 1.2% vs untreated 11.9 ± 1.1%, p < 0.05). The anti-atherosclerotic effect conferred by alagebrium and quinapril was associated with a significant reduction in vascular oxidative stress and circulating AGEs and methylglyoxal, although preformed AGEs were not removed from the vascular wall with either delayed intervention.

CONCLUSIONS/INTERPRETATION

Inhibition of AGE accumulation, using a delayed intervention with alagebrium or pyridoxamine, significantly attenuated the progression of established diabetes-associated atherosclerosis, similar to results obtained with quinapril. These findings provide further evidence that blockade of AGE-mediated pathways may present a novel therapy for the prevention of atherosclerosis in diabetes.

Analysis of quinapril by two solvent-saving methods: application of capillary column high-performance liquid chromatography with ultraviolet absorbance detection and LDI-TOF-MS

A capillary column high-performance liquid chromatography (CapLC) method and a laser desorption ionization-time of flight (LDI-TOF)-MS method are described for the determination of quinapril, an angiotensin-converting enzyme inhibitor. Effective separation was achieved by using a C18 capillary column at a flow rate of 10 microL/min. For CapLC, quinapril and 7-hydroxycoumarin (internal standard) were detected at 210 and 320 nm, respectively. Phenformin replaced 7-hydroxycoumarin as the internal standard for the LDI-TOF-MS method successfully developed to detect quinapril. The calibration curves showed good linearity in the range of 1-100 micro/mL in these two methods. For high throughput purposes, the LDI-TOF-MS method was simpler and faster than the CapLC method. Both green methods were suitably validated and successfully applied to determine quinapril in commercial tablets.

The endothelin receptor antagonist avosentan ameliorates nephropathy and atherosclerosis in diabetic apolipoprotein E knockout mice

AIMS/HYPOTHESIS

There is convincing evidence that the endothelin system contributes to diabetic nephropathy and cardiovascular disease. This study aimed to assess the effects of the non-peptidergic endothelin receptor A (ETA) antagonist avosentan in a mouse model of accelerated diabetic nephropathy and atherosclerosis in comparison with the ACE inhibitor, quinapril.

METHODS

Apolipoprotein E (Apoe) knockout (KO) mice (n = 20 per group, five groups) were randomised to the following groups: non-diabetic controls and streptozotocin-induced diabetic animals gavaged daily for 20 weeks with placebo, avosentan (high dose: 30 mg/kg, or low dose: 10 mg/kg) or quinapril (given in drinking water, 30 mg/kg).

RESULTS

BP was unchanged by avosentan treatment but decreased with quinapril treatment. Diabetes-associated albuminuria was significantly attenuated by high-dose avosentan after 10 and 20 weeks of treatment. Diabetic animals showed a decreased creatinine clearance, which was normalised by avosentan treatment. In diabetic mice, high-dose avosentan treatment significantly attenuated the glomerulosclerosis index, mesangial matrix accumulation, glomerular accumulation of the matrix proteins collagen IV, and renal expression of genes encoding connective tissue growth factor, vascular endothelial growth factor, transforming growth factor beta and nuclear factor kappaB (p65 subunit). Furthermore, high-dose avosentan treatment was also associated with reduced expression of the genes for ETA, ETB and angiotensin receptor 1. The renoprotective effects of avosentan were comparable or superior to those observed with quinapril. High-dose avosentan also significantly attenuated diabetes-associated aortic atherosclerosis in Apoe KO mice and reduced macrophage infiltration and aortic nitrotyrosine expression.

CONCLUSIONS/INTERPRETATION

This study demonstrates that ETA blockade with avosentan may provide an alternate therapeutic strategy for the treatment of diabetic micro- and macrovascular complications.

Effect of quinapril on in-stent restenosis and relation to plasma apoptosis signaling molecules

Angiotensin-converting enzyme inhibitors have been reported to inhibit in-stent restenosis. To assess the effect of angiotensin-converting enzyme inhibition on in-stent restenosis and its relation to apoptosis, 86 patients with chronic coronary artery disease who required stent implantation in the left anterior descending coronary artery or a major diagonal branch were studied. Patients were randomized to receive quinapril 40 mg/day orally (n = 43) or a placebo (n = 43). Drug therapy was initiated 1 week before initial stenting and continued for 6 months. Plasma levels of the apoptotic signaling molecules soluble Fas and soluble Fas ligand obtained from blood drawn from the left anterior descending coronary artery were measured just before initial stenting and 6 months later, at the time of repeat coronary angiography. In-stent restenosis was present in 9.3% of patients in the quinapril group and 25.6% of patients in the placebo group (p = 0.047). Mean late luminal loss was 0.56 +/- 0.51 mm in the quinapril group and 0.95 +/- 0.95 mm in the placebo group (p = 0.003). There were no significant differences in plasma soluble Fas or soluble Fas ligand levels at baseline. At 6 months, the change in plasma soluble Fas level was significantly higher in the quinapril group (0.72 +/- 1.24 ng/ml) than in the placebo group (0.28 +/- 0.72 ng/ml) (p = 0.024). The change in plasma soluble Fas ligand levels at 6 months was significantly higher in the quinapril group (7.43 +/- 12.2 pg/ml) than in the placebo group (0.06 +/- 6.8 pg/ml) (p = 0.002). In conclusion, the angiotensin-converting enzyme inhibitor quinapril inhibits in-stent restenosis by stimulating apoptosis after percutaneous intervention.

Influence of humidity and hydroxypropyl cellulose, hydroxypropylmethyl cellulose, glyceryl behenate or magnesium stearate on the degradation kinetics of quinapril hydrochloride in solid phase

Catalytic effect of hydroxypropyl cellulose, hydroxypropylmethyl cellulose, glyceryl behenate and magnesium stearate in the presence of 50.9% - 76.4% humidity at 318 K on stability of quinapril hydrochloride (QHCl) was examined by HPLC method. The differences in kinetic mechanism of degradation of QHCl were observed. The effect of humidity on QHCl stability in the presence of hydroxypropyl cellulose, hydroxypropylmethyl cellulose, glyceryl behenate or magnesium stearate was linear and according to the equation ln k(i) = aRH% + b.

An experimental model of encapsulating peritoneal sclerosis

In Japan, only about 3% of all patients with end-stage renal disease are maintained by continuous ambulatory peritoneal dialysis (CAPD). Although the reasons for the low proportion of patients receiving CAPD are multifactorial, encapsulating peritoneal sclerosis (EPS), a fatal complication of CAPD, is a major factor. In 1995 we developed a rat model of EPS, and in 2001 also developed an EPS model in mice. These rodent EPS models are reliable, reproducible, and inexpensive and have been used by other investigators. The renin-angiotensin system negatively regulates the transforming growth factor-beta signaling pathway, which plays a major role in tissue fibrosis. To investigate the anti-EPS effect of renin-angiotensin system inhibition, an angiotensin-converting enzyme inhibitor, quinapril, was administered to an EPS model in mice. Quinapril was found to inhibit EPS, both macro- and microscopically, in a dose-dependent manner. We report our experience of developing the experimental in vivo EPS model, and the inhibitory effect of this angiotensin-converting enzyme inhibitor on EPS.

[Combined antihypertensive treatment of patients with hypertension and type 2 diabetes mellitus]

AIM

To investigate antihypertensive efficacy, effects on endothelial, diastolic function of the left ventricle and metabolism of combination of ACE inhibitor quinapril (accupro) with diuretic indapamide SR in patients with hypertension of the second-third degree and type 2 diabetes mellitus (DM) and free of DM.

MATERIAL AND METHODS

Outpatient treatment was given to 60 patients with AH (mean age 55.3 +/- 9.6 years) in combination with mild or moderate DM (group 1) and free of DM (group 2). The patients were observed for 12 weeks. Clinical and biochemical blood tests, ECG, echo-CG, measurements of blood pressure were made in all the patients.

RESULTS

Quinapril course (mean dose 23.3 +/- 9.8 mg/day) in combination with indapamide (1.5 mg/ day) produced a complete hypotensive effect in group 1 (23 patients, 76.7%), in group 2--25 (83.3%). DM patients demonstrated reduction of fasting and postprandial glycemia and cholesterol, time of isovolumic relaxation reduced in group 1 by 9.1%, in group 2 by 19.8% (p < 0.01). Left ventricular diastolic function improved, endothelium-dependent vasodilation in diabetics rose by 40%, non-endothelium-dependent--by 21.8%, in hypertensive patients free of DM--by 51.9 and 43.2%, respectively.

CONCLUSION

Combination of quinapril with indapamide produces a significant antihypertensive effect in patients with AH of degree II-III associated with type 2 DM, improves carbohydrate and lipid metabolism, left ventricular diastolic function.

[Combined antihypertensive therapy in patients with arterial hypertension and type 2 diabetes]

The aim of the study was to assess effect of 12-week long combined therapy with quinapril (accupro), an ACE inhibitor, and diuretic indapamide SR on arterial pressure (AP), carbohydrate and lipid metabolism, and safety of the treatment in patients having arterial hypertension (AH) with and without DM2. Sixty outpatients with grade II-III AH (mean age 55.3 +/- 9.6 yr) were divided into 2 groups: group 1 (n = 30) comprised patients with AH and DM2, group 2 (n = 30) included patients with AH alone. Combined therapy with daily doses of 23.3 +/- 9.8 g accupro and 1.5 mg indapamide reduced systolic and diastolic AP by 30.2 and 27.3% respectively in group 1 and by 27.6 and 27.1% in group 2. In patients with AH and DM2, fasting and postprandial blood glucose levels decreased by 7.3 and 5.2% and HbA1c by 8.9% (p < 0.05). Total cholesterol, triglycerides, and LDL cholesterol tended to decrease in both groups. HDL cholesterol significantly (p < 0.05) increased by 11.1% in group 1 and 10% in group 2 Side effects were documented only in 8.3% of the patients and did not require withdrawal of therapy. It is concluded that antihypertensive treatment with quinapril (accupro), an ACE inhibitor, and diuretic indapamide SR may be recommended for long-term therapy of AH concomitant with DM2.

Comparison of the effects of quinapril and irbesartan on P-wave dispersion in hypertensive patients

INTRODUCTION

P-wave dispersion (PWD) has been shown to be a non-invasive electrocardiographic predictor for development of atrial fibrillation (AF). Thus, it may be possible to attenuate AF risk through improvement of PWD. In this study, we compared the effects of an angiotensin-converting enzyme (ACE) inhibitor, quinapril, and an angiotensin receptor blocker (ARB), irbesartan, on PWD.

METHODS

A total of 38 newly diagnosed hypertensive patients were enrolled in the study. The patients were randomly assigned to receive treatment with either irbesartan (150-300 mg) or quinapril (20-40 mg). P-wave durations and PWD were measured at baseline and after 6 and 12 months of treatment. Echocardiographic examinations were performed at baseline and after 12 months of treatment.

RESULTS

Both drugs significantly reduced blood pressure to a similar degree (P<0.001). Deceleration time (both P<0.001) and isovolumetric relaxation time (both P=0.007) were also significantly reduced, whereas there was no significant change in the early diastolic flow/atrial contraction signal ratio. Both irbesartan and quinapril significantly decreased maximum P-wave duration (Pmax) (P<0.001 and P=0.002, respectively) and PWD (from 68.0+/-22.1 to 41.0+/-25.1 msec for irbesartan, and from 70.5+/-20.4 to 46.6+/-13.3 msec for quinapril; both P<0.001). Baseline and follow-up blood pressure, heart rate, echocardiographic findings, and P-wave values were not significantly different between the irbesartan and quinapril groups. No patient developed AF during follow-up. There was no significant correlation between PWD and blood pressure or diastolic function parameters.

CONCLUSION

Antihypertensive treatment with either irbesartan or quinapril is associated with significant reductions in Pmax and PWD.

Electrochemical behavior of quinapril and its determination in pharmaceutical formulations by square-wave voltammetry at a mercury electrode

The electrochemical behavior of the antihypertensive drug quinapril was investigated at a hanging mercury drop electrode using different voltammetric techniques such as cyclic voltammetry, square-wave voltammetry and chronoamperometry. A simple and sensitive square-wave voltammetric method for the electrochemical analysis of quinapril in its pharmaceutical formulations was developed and validated. The experimental and instrumental parameters affecting the peak current of quinapril were investigated. Various buffers such as Britton Robinson, borate and phosphate buffers at different pH values (3.0-11.0) were examined as supporting electrolyte. The optimum conditions were obtained using Britton Robinson buffer at pH 10.0 and frequency: 50 Hz, scan increment: 4 mV and pulse amplitude: 25 mV. A well-defined peak current was observed at the hanging mercury drop electrode at -1100 mV vs. Ag/AgCl reference electrode. This proposed method was validated by evaluating linearity, sensitivity, repeatability, accuracy, precision, selectivity, recovery, robustness and ruggedness. The linear calibration range was 0.50-8.68 microg mL-' (r = 0.9992). The detection and quantification limits of this method were 0.22 and 0.50 Ctg mL(-1) and intra-day and inter-day precision were between 0.81-4.32% (n = 7), respectively. The developed method was applied successfully for the determination of quinapril in its tablet dosage forms. The average amount of quinapril in tablets was found as 20.26 +/- 0.12 with RSD of 1.60% for 20 mg tabletsand 40.55 +/- 0.23 with RSD of 1.52% for 40 mg tablets.

Pharmacokinetics and bioequivalence study of the two 20-mg quinapril hydrochloride tablet formulations in healthy Thai male volunteers

OBJECTIVE

To determine the pharmacokinetics and bioequivalence of two 20-mg quinapril hydrochloride tablet preparations; Quinaril (The Biolab Ltd, Bangkok, Thailand) as the test and Accupril as the reference.

MATERIAL AND METHOD

The present study was a single dose, randomized two-period crossover design conducted in 24 healthy volunteers under fasting conditions with a 7-day washout period. Serial plasma concentrations of quinapril and its active metabolite quinaprilat up to 24 h after dosing were determined by HPLC with UV detection. The pharmacokinetic parameters were analyzed by noncompartmental analysis and the ANOVA was carried out using logarithmically transformed data of the AUC and C as well as untransformed T(max).

RESULTS

There were no significant differences between the two preparations regarding the T(max) of quinapril and quinaprilat and their median T(max) were 0.5 h and 1.4 - 1.5 h, respectively. The half-life of quinapril (1.2 h) was faster than quinaprilat (1.8-1.9 h) although the volume of distribution (Vd/F) of quinapril (1.1 L/kg) was larger than quinaprilat (0.3 L/kg), however, its clearance rate (CL/F) was faster when compared to quinaprilat (20-26 ml/min/kg vs. 1.7 ml/min/kg). The mean (90% CI) for the ratios Reference/Test of quinapril were 0.99 (0.89-1.10), 0.99 (0.90-1.09) and 1.01 (0.90-1.14), respectively for AUC(0-24), AUC(0-infinity) and C(max). Similarly, the corresponding values for quinaprilat were 0.95 (0.90-1.01), 0.95 (0.90-1.01) and 1.03 (1.00-1.07), respectively. These values were within the bioequivalence range of 0.80 - 1.25, thus, demonstrated the bioequivalence of the two preparations.

CONCLUSION

The results of the present study indicated that the two quinapril HCL preparations are bioequivalent and it can be assumed that they are therapeutically equivalent and exchangeable in clinical practice.

Skeletal muscle capillary responses to insulin are abnormal in late-stage diabetes and are restored by angiotensin-converting enzyme inhibition

Acute physiological hyperinsulinemia increases skeletal muscle capillary blood volume (CBV), presumably to augment glucose and insulin delivery. We hypothesized that insulin-mediated changes in CBV are impaired in type 2 diabetes mellitus (DM) and are improved by angiotensin-converting enzyme inhibition (ACE-I). Zucker obese diabetic rats (ZDF, n = 18) and control rats (n = 9) were studied at 20 wk of age. One-half of the ZDF rats were treated with quinapril (ZDF-Q) for 15 wk prior to study. CBV and capillary flow in hindlimb skeletal muscle were measured by contrast-enhanced ultrasound (CEU) at baseline and at 30 and 120 min after initiation of a euglycemic hyperinsulinemic clamp (3 mU.min(-1).kg(-1)). At baseline, ZDF and ZDF-Q rats were hyperglycemic and hyperinsulinemic vs. controls. Glucose utilization in ZDF rats was 60-70% lower (P < 0.05) than in controls after 30 and 120 min of hyperinsulinemia. In ZDF-Q rats, glucose utilization was impaired at 30 min but similar to controls at 120 min. Basal CBV was lower in ZDF and ZDF-Q rats compared with controls (13 +/- 4, 7 +/- 3, and 9 +/- 2 U, respectively). With hyperinsulinemia, CBV increased by about twofold in control animals at 30 and 120 min, did not change in ZDF animals, and increased in ZDF-Q animals only at 120 min to a level similar to controls. Anatomic capillary density on immunohistology was not different between groups. We conclude that insulin-mediated capillary recruitment in skeletal muscle, which participates in glucose utilization, is impaired in animals with DM and can be partially reversed by chronic ACE-I therapy.

Therapeutic modulation of the nitric oxide: all ace inhibitors are not equivalent

The properties of the angiotensin-converting enzyme (ACE) inhibitors have largely been attributed to a class effect. However, this opinion is now increasingly challenged in view of the findings from recent clinical trials, which have demonstrated differential effects of ACE inhibitors, in particular with respect to secondary cardiovascular prevention outcomes. In this experimental study, Sprague-Dawley rats were treated with five different ACE inhibitors (enalapril, perindopril, quinapril, ramipril, and trandolapril) at equihypotensive doses. All ACE inhibitors increased endothelial nitric oxide synthase (eNOS) protein expression and activity in the aorta (both P<0.0001 versus vehicle) and in cardiac myocytes (both P<0.05 versus vehicle). A highly significant effect was observed with perindopril when compared with vehicle in the modulation of eNOS protein expression and activity in aorta (22.52+/-1.09 versus 9.12+/-0.57 AU microg(-1) protein and 1.59+/-0.03 versus 0.77+/-0.02 pmol l(-1) citrulline min(-1)mg protein(-1), respectively) and in cardiac myocytes (17.64+/-0.94 versus 11.30+/-0.59 AU microg(-1) protein and 0.93+/-0.02 versus 0.62+/-0.03 pmol l(-1) citrulline min(-1)mg protein(-1), respectively). On the basis of the eNOS protein expression in the rat aorta, the other ACE inhibitors had similar, but lower effects. Indeed, the rank of potency - based both on eNOS protein expression and activity - was perindopril>trandolapril approximately quinapril approximately ramipril approximately enalapril (P<0.05 perindopril versus trandolapril and ramipril and P<0.01 perindopril versus enalapril, respectively). Levels of circulating nitrite/nitrate, the end-metabolites of nitric oxide, were also significantly affected by ACE inhibition, with the same order of potency. Our findings provide further evidence in favor of differential effects associated with ACE inhibitor therapy and suggest that the clinical benefits associated with these drugs may not solely reflect a class effect extending their benefit beyond blood pressure-lowering effect.

Influence of enalapril, quinapril and losartan on lipopolysaccharide (LPS)-induced serum concentrations of TNF-alpha, IL-1 beta, IL-6 in spontaneously hypertensive rats (SHR)

Immunopharmacological studies of drugs used in cardiovascular diseases provide new data concerning their modulating effect on the levels of proinflammatory cytokines, chemokines and adhesion molecules. Therefore, we have made an attempt to find out whether enalapril, quinapril and losartan (drugs used in the treatment of arterial hypertension) are able to modulate lipopolysaccharide (LPS)-induced proinflammatory cytokine serum concentrations (tumor necrosis factor alpha - TNF-alpha, interleukin-1 beta _ IL-1 beta, interleukin-6 - IL-6) in spontaneously hypertensive rats (SHR). The animals were divided into four groups as follows: SHR + M (control rats receiving 1% solution of methylcellulose), SHR + E (rats receiving enalapril - 10 mg/kg), SHR + Q (rats receiving quinapril - 10 mg/kg) and SHR + L(rats receiving losartan - 20 mg/kg). 1% solution of methylcellulose and hypotensive drugs were administered by a gavage for 21 days. Arterial blood pressure was measured in conscious rats, using the tail-cuff method. Twenty four hours after the last administration of enalapril, quinapril, losartan or 1% solution of methylcellulose, the rats received a single dose of LPS (ip; 0.1 mg/kg). After 2 h, the rats were anesthetized with ether and the blood samples were collected by heart puncture. Serum TNF-alpha, IL-1 beta and IL-6 concentrations were measured with enzyme-linked immunosorbent assay kits. Additionally, total cholesterol and high density lipoprotein (HDL) cholesterol were evaluated. Enalapril, quinapril and losartan significantly decreased LPS-stimulated TNF-alpha and IL-1 beta level after 21 days. Three-week administration of quinapril lowered IL-6 serum concentration after LPS stimulation. Enalapril and losartan did not affect the IL-6 level. The results were accompanied by a statistically significant decrease in systolic, diastolic and mean blood pressure. Hypotensive drugs also showed no effect on lipid level. The latest data indicate additional properties of hypotensive drugs. However, further studies are necessary to elucidate precisely the role of proinflammatory cytokines in arterial hypertension.

Angiotensin receptor antagonist vs. angiotensin-converting enzyme inhibitor in Asian subjects with type 2 diabetes and albuminuria - a randomized crossover study

BACKGROUND

Subjects with type 2 diabetes mellitus (T2DM) and albuminuria are at risk for progressive diabetic nephropathy. The relative blood pressure lowering and antialbuminuric efficacy of angiotensin receptor antagonist (ARB) vs. angiotensin-converting enzyme (ACE) inhibitor has not been well studied.

METHODS

Forty-one ARB- and ACE inhibitor-naive T2DM subjects with albuminuria (>30 mg/g creatinine) were given either 50 mg of losartan (ARB) or 20 mg of quinapril (ACE inhibitor) (50% maximum dose) for 4 weeks, with a 4-week wash-out period in-between interventions in a crossover fashion. The order of intervention was randomized. The primary endpoint was the reduction of blood pressure and albuminuria. Secondary endpoint was changes in plasma transforming growth factor beta (TGF-beta).

RESULTS

Among the 41 subjects, 66% were male. The mean age (s.d.) was 52 (10) years, and duration of diabetes was 8 (14) years. Blood pressure reduction (though not statistically significant) was similar on both interventions [systolic: losartan 3 (15) vs. quinapril 2 (13) mmHg, p = 0.52; diastolic: losartan 1 (9) vs. quinapril 2 (8) mmHg, p = 0.55]. However, amelioration of albuminuria [mean (s.e.)] was significantly greater with losartan [losartan vs. quinapril: -93 (82) vs. -49 (65) mg/g, p = 0.02]. There was no change in plasma TGF-beta levels [mean (s.d.)] on either treatment, losartan [before 12.1 (8.9) vs. after 11.9 (9.6) ng/ml, p = 0.68] and quinapril [11.1 (7.9) vs. 11.1 (7.8) ng/ml, p = 0.87).

CONCLUSION

In Asian subjects with T2DM and albuminuria, 4 weeks of losartan therapy at 50 mg daily appeared to have greater antialbuminuric effect than 20 mg of quinapril.

Influence of preventive therapy with quinapril on IL-6 level in patients with chronic stable angina

We hypothesized that beneficial role of angiotensin converting enzyme inhibitors in stable coronary artery disease (CAD) therapy may involve (among others) their anti-inflammatory effects, which may be reflected by serum interleukin-6 (IL-6) levels. For that reason, we have investigated the influence of short-term administration of quinapril on serum IL-6 concentration. 124 patients suffering from stable CAD and matched for some of CAD risk factors were enrolled in our study. Patients were randomized to treatment with quinapril or control (placebo administration). Blood samples were taken twice: before and after four weeks of quinapril administration. The effect of quinapril administration was assessed under double-blind placebo-controlled conditions. We observed that quinapril reduced serum IL-6 concentration in almost all studied subgroups of patients (p < 0.001). Interestingly, such an effect was not observed in smokers. Additionally, we found that baseline IL-6 levels were higher in: smokers as compared with nonsmokers (p < 0.001), patients with total cholesterol (TC) to high density lipoprotein (HDL)-cholesterol ratio (TC/HDL-ch ratio) above 5 as compared with subjects with TC/HDL-ch < or = 5 (p = 0.001), and in patients who did not report any statin therapy in comparison with patients undergoing statin treatment (p = 0.023). In conclusion, quinapril may interfere with cytokine release by lowering IL-6 levels, which may be of particular importance for secondary prevention of stable CAD.

Acute effects of renin-angiotensin system blockade on arterial function in hypertensive patients

The acute effects of the renin-angiotensin system (RAS) blockers may be important in some clinical settings. To assess the acute impact of such drugs on arterial function, we studied the effects of captopril 25 mg, quinapril 20 mg and telmisartan 80 mg on 100 hypertensive patients, according to a randomized, double-blind, placebo-controlled study. Central (aortic) blood pressure (BP) and augmentation index (AIx, a measure of wave reflections), as well as flow-mediated dilatation (FMD) of the brachial artery and forearm blood flow (FBF) (measures of conduit and resistance artery endothelial function, respectively), were evaluated before and 2 h after oral drug administration. Compared to placebo, captopril and quinapril decreased central systolic (by 7.5 mm Hg, P<0.05 and by 12.3 mm Hg, P<0.001) and diastolic BP (by 4.9 mm Hg, P<0.01 and by 8.4 mm Hg, P<0.001), whereas telmisartan had no significant effect (P=NS). Additionally, AIx was reduced after quinapril (absolute decrease of 7.2%, P<0.01) and marginally after captopril (decrease of 4.7%, P=0.07). Only quinapril led to a beneficial change of FMD (absolute increase of 2.7%, P<0.001). No treatment was related to significant changes of peak hyperaemic or 3-min hyperaemic FBF. In adjusted analyses, all the favourable alterations induced by quinapril were independent of potential confounding haemodynamic factors. Our data show that acute RAS inhibition with quinapril (20 mg) may be more beneficial in terms of arterial function and central haemodynamics compared to captopril (25 mg) or telmisartan (80 mg). Further studies are needed to investigate whether these acute arterial effects of quinapril are clinically significant.

Anti-inflammatory actions of quinapril

OBJECTIVE

The role of angiotensin II (Ang-II) in inflammation and the mechanisms through which it exerts this role are explored. Signaling through angiotensin stimulation of inflammatory cells often amplifies inflammation. Formation of Ang-II from tissue angiotensin-converting enzyme (ACE) has been shown to be of greater importance in the development and progression of inflammatory diseases than plasma ACE.

CONCLUSION

Quinapril, which is a potent and selective inhibitor of both plasma and tissue ACE, has demonstrated anti-inflammatory properties in many disease states such as atherosclerosis, nephritis, scleroderma, diabetes and arthritis, and, thus, offers new therapeutic possibilities for disease treatment.

Inhibition of matrix metalloproteinase activity by ACE inhibitors prevents left ventricular remodeling in a rat model of heart failure

Angiotensin-converting enzyme (ACE) inhibitors represent the front-line pharmacological treatment of heart failure, which is characterized by left ventricular (LV) dilatation and inappropriate hypertrophy. The mechanism of action of ACE inhibitors is still unclear, but evidence suggests that they may act by influencing matrix metalloproteinase (MMP) activity. This study sought to determine whether ACE inhibitors can directly regulate MMP activity and whether this results in positive structural and functional adaptations to the heart. To this end, MMP-2 activity in LV tissue extracted from rats with an aortocaval (AV) fistula was assessed by in vitro incubation as well as in vivo treatment with captopril, lisinopril, or quinapril. Furthermore, LV size and function were determined in untreated AV fistula rats, AV fistula rats treated with lisinopril (3, 5, and 8 wk), and age-matched sham-operated controls. In vitro incubation with captopril, lisinopril, or quinapril significantly reduced MMP-2 activity, as did in vivo treatment. This occurred without a reduction in the available pool of MMP-2 protein. Long-term in vivo administration of lisinopril also prevented LV dilatation, attenuated myocardial hypertrophy, and prevented changes in myocardial compliance and contractility. The results herein demonstrate that ACE inhibitors prevent MMP-2 activity and, in so doing, represent a mechanism responsible for preventing the negative structural and functional changes that occur in the rat AV fistula model of heart failure.

Clearance of Imidapril, an Angiotensin-Converting Enzyme Inhibitor, During Hemodialysis in Hypertensive Renal Failure Patients: Comparison With Quinapril and Enalapril

The dialyzability of imidaprilat, an active metabolite of the angiotensin-converting enzyme (ACE) inhibitor imidapril, was determined and compared with those of enalaprilat and quinaprilat in hypertensive patients on chronic hemodialysis. Imidapril (5 mg/d, n = 6), enalapril (2.5 mg/d, n = 6), or quinapril (2.5 mg/d, n = 6) was given for at least 8 weeks prior to the trial. During dialysis, enalaprilat, but not imidaprilat or quinaprilat, concentrations in both sides decreased significantly. Compared to enalaprilat, the dialyzabilities of imidaprilat and quinaprilat were significantly lower (dialyzer clearance [mL/min/m(2)]: enalaprilat, 41.8 +/- 7.4; imidaprilat, 19.0 +/- 7.8; quinaprilat, 8.9 +/- 1.3). The dialyzabilities of the 3 drugs were negatively correlated with their respective protein-binding rates. During hemodialysis, blood pressure did not change significantly in any group. These results suggest that imidapril provides good blood pressure control without a large fluctuation of drug concentration in hypertensive patients undergoing chronic hemodialysis.

Amlodipine Added to Quinapril vs Quinapril Alone for the Treatment of Hypertension in Diabetes: The Amlodipine in Diabetes (ANDI) Trial

This randomized, comparative, parallel-group trial investigated strategies of blood pressure (BP)-lowering in patients with diabetes and hypertension. Patients not reaching goal BP (<130/80 mm Hg) after 4-week open-label treatment with quinapril 20 mg/d (n=374) received 40 mg/d quinapril (n=167) or 20 mg/d quinapril plus amlodipine besylate (5 mg/d; n=162) for 6 weeks. Patients receiving combination therapy vs monotherapy had significantly greater reductions in mean +/- SE sitting systolic BP (9.9+/-1.0 mm Hg vs 4.3+/-1.1 mm Hg; P<.001) and diastolic BP (6.5+/-0.6 mm Hg vs 2.7+/-0.6 mm Hg; P<.001). No significant differences between groups were observed in percentage of patients achieving goal BP (10.1% with combination therapy vs 8.2% with monotherapy). A clinically neutral effect was observed on high-sensitivity C-reactive protein in both groups. Treatments were well tolerated; fewer than 3% of patients in any group discontinued due to treatment-emergent or treatment-related adverse events. In diabetic hypertensive patients, 20 mg/d quinapril plus 5 mg/d amlodipine besylate was a more effective BP-lowering strategy than monotherapy with 40 mg/d quinapril.

Auto-intoxication with flecainide and quinapril: ECG-changes, symptoms and treatment

Flecainide acetate is a sodium channel blocker and a class Ic antiarrhythmic agent with potential life-threatening proarrhythmic and cardioinhibitory properties when taken in overdose. Quinapril is an angiotensin-converting enzyme inhibitor (ACE-inhibitor) and overdose can lead to prolonged hypotension and, less frequently, transient renal impairment. We describe the first published case of intoxication with both drugs. The patient developed a broad-QRS-tachycardia and severe hypotension. Treatment with volume expansion, hypertonic sodium bicarbonate, inotropic support with norepinephrine and insertion of an intra-aortic balloon pump led to complete recovery after 72 hours. We assume that the clinical picture was mainly dictated by flecainide intoxication. Relevant literature data are discussed.

Quinapril for Treatment of Hypertension in Turkey

BACKGROUND AND OBJECTIVE

Recently the PatenT (Prevalence, awareness, treatment and control of hypertension in Turkey) study showed that while the prevalence of hypertension in Turkey is high, effective control of BP is infrequently achieved. This study investigated the efficacy and safety of quinapril (as monotherapy or in combination with hydrochlorothiazide [HCTZ]) for achieving BP control (target <140/90 mm Hg) in Turkish subjects with mild to moderate hypertension.

METHODS

Two-hundred male and female outpatients aged 19-65 years with mild to moderate hypertension (stage I or II, Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure 7 guidelines) entered this 12-week, open-label study. All subjects received quinapril 20 mg/day for 6 weeks. If BP targets were achieved at week 6, responders were maintained on 20 mg/day; if BP targets were not achieved, non-responders were randomised to quinapril 40 mg/day or quinapril 20 mg/day + HCTZ 12.5 mg/day for the remainder of the study.

RESULTS

After 6 weeks, 63% of subjects achieved BP targets, and 82% of week-6 responders who continued on quinapril 20 mg/day maintained BP targets at week 12. Of the non-responders, 50% and 52% randomised to quinapril 40 mg/day or quinapril 20 mg/day + HCTZ 12.5 mg/day, respectively, went on to achieve BP targets by week 12. Safety was not compromised with increased dosages or use of combination therapy.

CONCLUSION

Quinapril was an effective and safe treatment for achieving and maintaining recommended BP targets in this sample population. These findings will provide clinicians in Turkey with valuable data on the use of quinapril for effective control and management of hypertension.

Analysis of antihypertensive drugs in the heart of animal models: a proteomic approach

Arterial hypertension is the most frequent chronic disease and it is an important cause of morbidity and mortality in the developed world. Arterial hypertension is associated with such adverse effects as accelerated arteriosclerosis and pathological left ventricular hypertrophy, among others. The molecular mechanisms affecting left ventricular hypertrophy remain mostly unknown. The advent of proteome profiling has facilitated the elucidation of disease-associated proteins, paving the way for molecular diagnostics and the identification of novel therapeutic targets. We explored the proteomic profile of pathological left ventricular hypertrophy in comparison with normal heart in a model of rats and investigated the proteomic changes in response to different antihypertensive regimens in order to elucidate their cardioprotective effects. Here we describe in depth the protocol for this type of study.

Effect of angiotensin converting enzyme inhibitors on 1.25-(OH)2 D levels of hypertensive patients. Relationship with ACE polymorphisms

BACKGROUND

The effect of angiotensin converting enzyme inhibitors (ACEIs) on 1.25-dihydroxyvitamin D [1.25-(OH)2D] levels has not been studied. The purpose of this study is to assess the relationship between 1.25-dihydroxyvitamin D levels and I/D angiotensin-converting enzyme polymorphism (ACE) in hypertensive patients.

MATERIALS AND METHODS

The study included 60 individuals (31 females and 29 males) with systolic and/or diastolic hypertension. The 25-hydroxyvitamin D levels were measured by HPLC and the 1.25-(OH)2 D was determined by RIA. ACE polymorphism was analyzed by Polymerase Chain Reaction (PCR) using a modification of the original method described by Rigat.

RESULTS

Treatment with ACEIs produced an increase in total calcium (p=0.003) and a decrease in the 1.25-(OH)2 D (p=0.0001). No relationship between final calcium and 1.25-(OH)2 D (r=-0.171, p=0.198) was observed. When the effects of enalapril and quinapril were analyzed separately, the results were similar. When the patients were divided according to genotype, the decrease in 1.25-(OH)2 D was observed only in patients with D allele, genotype Ins/Del (69+/-23 vs. 48+/-19, p=0.021 ) and in those of genotype Del/Del (64+/-19 vs. 17, p=0.004).

CONCLUSION

The ACE inhibitors in combination with the presence of the DD genotype decrease the level of 1.25-(OH)2 D. There was no difference between enalapril and quinapril treated groups.

Cardiorenal protective effects of year-long antihypertensive therapy with an angiotensin-converting enzyme inhibitor or a calcium channel blocker in spontaneously hypertensive rats

BACKGROUND

The objective of this study was to evaluate the effect of year-long antihypertensive therapy with a calcium channel blocker and an angiotensin-converting enzyme (ACE) inhibitor on cardiac and renal injury.

METHODS

Male 15-week-old spontaneously hypertensive rats (SHR) were given either a normal diet and normal drinking water (n = 10), a diet containing 0.05% nitrendipine (n = 10), or drinking water containing 50 mg/L of quinapril (n = 10). After 12 months of antihypertensive treatment, cardiovascular organ injuries were evaluated.

RESULTS

Tail-cuff blood pressure (BP) at 12 months was significantly lower in animals receiving nitrendipine or quinapril than in control animals (control, 231 +/- 2 mm Hg; nitrendipine, 194 +/- 3 mm Hg; quinapril, 191 +/- 3 mm Hg; P < .001). Furthermore, aortic thickness was reduced by nitrendipine (-19%, P < .001) or quinapril (-21%, P < .001), and cardiac ventricular weight was significantly reduced by quinapril (-18%, P < .001) but not by nitrendipine (-5%, P = not significant [NS]). Echocardiography at 12 months revealed that midwall fractional shortening was higher in the quinapril group than in the control or the nitrendipine groups (control, 9.3% +/- 0.5%; nitrendipine, 9.8% +/- 0.5%; quinapril, 10.6% +/- 0.6%; P < .05). Left ventricular hydroxyproline levels were lower in the nitrendipine group (-21%, P < .01) and the quinapril group (-36%, P < .001) than in the control animals. In control SHR, creatinine clearance began to decrease and proteinuria began to increase at 6 to 9 months. Quinapril but not nitrendipine attenuated these markers of renal impairment (creatinine clearance at 12 months: control, 4.7 +/- 0.4 mL/min/kg; nitrendipine, 5.0 +/- 0.4 mL/min/kg; quinapril, 6.1 +/- 0.4 mL/min/kg; P < .05). Histologically, the glomerular injury score was lower in the quinapril group than in the control or nitrendipine groups (control, 19 [range, 8 to 30]; nitrendipine, 18 [range, 9 to 32]; quinapril, 7 [range, 3 to 12]; P < .01).

CONCLUSIONS

It is suggested that year-long antihypertensive therapy with an angiotensin-converting enzyme (ACE) inhibitor is superior to a calcium channel blocker in terms of cardiorenal protection in SHR.

Atorvastatin and quinapril inhibit blood coagulation in patients with coronary artery disease following 28 days of therapy

BACKGROUND

We evaluated the antithrombotic effects of statins and angiotensin-converting enzyme inhibitor (ACEI) drugs in patients with coronary artery disease (CAD).

METHODS AND RESULTS

Blood coagulation at the site of microvascular injury was assessed in 26 males with CAD before and after treatment with quinapril (10 mg day-1; n=13) or atorvastatin (40 mg day-1; n=13) for 4 weeks and an additional 4 weeks of combined therapy (quinapril+atorvastatin). Rates of prothrombin and factor V activation (FVa), fibrinogen (Fbg) cleavage and FVa inactivation showed that both quinapril and atorvastatin decreased the rates of: formation of thrombin B-chain (by 30.6%, P=0.007; and by 34.3%, P=0.003), formation of thrombin-antithrombin complexes (by 30.4%, P=0.0002; and by 40%, P=0.001), FV activation (by 19.1%, P=0.03; and by 21.8%, P=0.005) and Fbg depletion (by 29.2%, P=0.004; and by 32.7%, P=0.001). Atorvastatin alone accelerated FVa inactivation (P=0.005). A further 4 weeks of combined therapy enhanced most anticoagulant effects only when atorvastatin was added to quinapril.

CONCLUSIONS

In CAD patients, atorvastatin and quinapril slowed blood clotting at the site of microvascular injury after 28 days of therapy. Addition of atorvastatin to quinapril, but not quinapril to the statin, enhanced the anticoagulant effects. Our findings might help explain the reduced risk of myocardial infarction or stroke in patients treated with statins and/or ACEIs and the lack of clinical benefits from ACEI added to prior statin therapy in patients at cardiovascular risk.

Long-term treatment with an ACE inhibitor or an AT1 antagonist avoids hypertension-induced inflammation in the kidney

BACKGROUND

Hypertension causes an inflammatory response in the kidney. Many studies have demonstrated that activation of the renal renin-angiotensin system, and therefore an increase in local angiotensin II (AngII) production, participates in the renal inflammatory cell recruitment. Our aim was to investigate the role of AngII blockade in hypertension-induced inflammatory response.

METHODS

To replicate chronic hypertension with renal disease, we used a model of spontaneously hypertensive rats with unilateral nephrectomy (UNX-SHR). These animals were studied for 48 weeks. We investigated the effect of long-term treatment with an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin II type 1 (AT1 ) antagonist, 2 strategies currently used in humans, on renal proinflammatory parameters.

RESULTS

UNX-SHR rats presented elevated renal inflammatory cell infiltration and up-regulation of proinflammatory factors, including activation of nuclear factor chi B (NF-chi B) and related genes. Both ACE inhibition and AT 1 blockade decreased the number of inflammatory cells as well as the up-regulation of proinflammatory factors in the kidney.

CONCLUSIONS

These results suggest that either AT 1 blockade or ACE inhibition can stop the renal inflammatory process in chronic hypertension-associated inflammatory response.

Effects of angiotensin-converting enzyme inhibitors or an angiotensin receptor blocker in combination with aspirin and cilostazol on in-stent restenosis

It remains to be determined whether adding an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin II receptor blocker (ARB) to antiplatelet therapy has a therapeutic benefit on in-stent restenosis. After successful coronary stenting, 165 patients (167 lesions) were randomly assigned to a basal (aspirin 162 mg + cilostazol 200 mg/day), ACEI (basal treatment + quinapril 10 mg or perindopril 4 mg/day), or ARB (basal treatment + losartan 50 mg/day) treatment group. Quantitative coronary angiography was performed before, immediately following, and 6 months after stenting. Follow-up coronary angiography was completed in 126 patients (128 lesions). Restenosis rates tended to be higher (12, 26, and 12% for the basal, ACEI, and ARB groups, respectively), and target lesion revascularization rates were higher in the ACEI group than in the other groups (9, 23,* and 5%, respectively, *P < 0.05 versus basal group). Moreover, late lumen loss was higher in the ACEI group than in the basal group (0.60 +/- 0.55, 0.98 +/- 0.61* and 0.73 +/- 0.64 mm in the basal, ACEI, and ARB groups, respectively). The combinations of an ACEI or ARB with aspirin and cilostazol are ineffective for the prevention of in-stent restenosis, and an ACEI may even promote intimal proliferation after stent implantation.

Long-term organ protection by doxazosin and/or quinapril as antihypertensive therapy

BACKGROUND

Even with optimal blood pressure control, organ protection may also depend on the selected therapeutic regime. Angiotensin-converting enzyme inhibitors have been shown to provide excellent organ protection in hypertension, and may show dose-dependent protective effects. Adrenergic alpha blockers have been associated with an increased rate of heart failure in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) and Vasodilator-Heart Failure Trial (V-HeFT). This has been related to a proapoptotic effect of this drug in cardiomyocytes. Our purpose is to compare the heart and renal protection of a high quinapril dose, with a combined low quinapril dose plus doxazosin, in an animal model of chronic hypertension.

METHODS

Uninephrectomized spontaneously hypertensive 12-week-old rats were treated for 36 weeks with either quinapril or a combination of doxazosin plus a low quinapril dose. Tight blood pressure control was achieved with both treatments. Renal and cardiac protection was assessed by different parameters, and cardiac apoptosis was evaluated by active caspase-3, apoptotic protein and heat shock protein levels. Untreated hypertensive and normotensive rats were included as controls.

RESULTS

Both treatments showed significant heart and renal protection compared with untreated animals. Both therapeutic regimes showed similar protection in renal and cardiac pathology, coronary media fibrosis, myocardial apoptosis and cardiac index. Proteinuria and left ventricular hypertrophy regression were significantly lower in the quinapril group compared with the combined treatment group.

CONCLUSIONS

Blood pressure control with a high quinapril dose provided higher organ protection than a combined therapy with a lower quinapril dose. This effect was not due to a deleterious effect of doxazosin.

Interaction of quinapril anion with cationic surfactant micelles of cetyltrimethylammonium bromide

In this study, the interaction of the anion of quinapril (QUIN), angiotensin converting enzyme (ACE) inhibitor, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated. The effect of cationic micelles on the spectroscopic and acid-base properties of QUIN was studied at pH 8. The binding of QUIN anion to CTAB micelles implied a shift in drug acidity constant (pK(a)(water)-pK(a)(micelle)=1.39) proving the great affinity of negatively charged QUIN ion for the positively charged CTAB micelle surface. The strong dependence of the partition coefficient K(x) on QUIN concentration, obtained by using pseudo-phase model, is consistent with an adsorption-like phenomenon. From the dependence of differential absorbance at lambda=272 nm on CTAB concentration, by using mathematical model that treats the solubilization of QUIN anion as its binding to specific sites in the micelles (Langmuir adsorption isotherm), the binding constant K(b)=(2.3+/-0.4)x10(3) mol(-1)dm(3) was obtained. QUIN-CTAB binding constant was also calculated from micellar liquid chromatography (MLC) and this method was found to be not accurate enough for its determination.

Correlation of flow mediated dilation with inflammatory markers in patients with impaired cardiac function. Beneficial effects of inhibition of ACE

Impaired cardiac function is frequently accompanied by peripheral vascular dysfunction and a pro-inflammatory condition, which may be associated with elevated levels of angiotensin II. We hypothesized that the magnitude of flow mediated dilatation (FMD) of the brachial artery of post myocardial infarction patients will correlate with serum levels of tumor necrosis factor alpha (TNFalpha) and C-reactive protein (CRP), and that treatment with angiotensin converting enzyme inhibitors (ACEI) will increase FMD by reducing TNFalpha and CRP. Patients were treated with low dose (10 mg/day) quinapril (Q) or enalapril (E) and their effects on FMD and inflammatory markers were evaluated after 8 and 12 weeks. Before treatment, in both groups FMD showed a low value (Q: 2.95+0.42% and E: 3.3+/-0.33%), whereas TNF-alpha (Q: 31.65+/-8.23 pg/ml and E: 29.5+/-5.9 pg/ml) and CRP (Q: 7.28+/-2.96 mg/ml and E: 7.08+/-3.02 mg/ml) were elevated. In the Q group, but not in the E group FMD increased significantly, (to 5.96+1.10%), whereas TNF-alpha (19.0+/-12.21 pg/ml) and CRP (to 3.91+/-1.82 mg/L) significantly decreased after 8 and 12 weeks of Q treatment. Moreover, the magnitude of FMD showed a strong inverse correlation with serum levels of TNF-alpha and CRP after Q treatment. Thus, in post myocardial infarction patients endothelial dysfunction assessed by FMD correlates with elevated levels of plasma inflammatory markers, and low dose quinapril improves endothelial function, likely by reducing vascular inflammation.

Critical role of bradykinin-eNOS and oxidative stress-LOX-1 pathway in cardiovascular remodeling under chronic angiotensin-converting enzyme inhibition

To elucidate the molecular mechanisms of the cardioprotective effect of angiotensin-converting enzyme (ACE) inhibitors, we evaluated whether the effect of quinapril involved in bradykinin-endothelial nitric oxide synthase (eNOS) and oxidative stress-lectin-like oxidized LDL receptor-1 (LOX-1) pathway. Dahl salt-sensitive hypertensive (DS) rats were fed a diet containing 8% NaCl and treated with one of the following drug combinations for 5 weeks, from 6 weeks of age to left ventricular hypertrophy stage (11 weeks): vehicle; quinapril; quinapril plus the bradykinin B2 receptor antagonist FR172357; the NAD(P)H oxidase inhibitor apocynin; or quinapril plus apocynin. eNOS expression, which was decreased in hypertrophy stage, was significantly increased by quinapril and/or apocynin, but not by quinapril plus FR172357. Upregulated expression of NAD(P)H oxidase p22phox, p47phox, gp91phox and LOX-1 was significantly decreased by quinapril to a similar degree as after treatment with apocynin, but not by quinapril plus FR172357. Quinapril and/or apocynin treatment effectively ameliorated left ventricular weight and vascular changes such as increase in medial thickness and perivascular fibrosis and suppressed expression of transforming growth factor-beta1, type I collagen and fibronectin mRNA, but not that of quinapril plus FR172357. These results suggest that the ACE inhibitor quinapril may have cardioprotective effects in this model of hypertension mediated at least in part through effects on the bradykinin-eNOS and oxidative stress-LOX-1 pathway.