A sustainable activated carbon fiber/TiO2 cathode for the photoelectro-Fenton treatment of pharmaceutical pollutant enalapril

In this work, a TiO2-decorated electrode was fabricated by dip coating activated carbon fibers (ACF) with TiO2, which were then used as a cathode for the photoelectro-Fenton (PEF) treatment of the pharmaceutical enalapril, an angiotensin-converting enzyme inhibitor that has been detected in several waterways. The TiO2 coating was found to principally improve the electrocatalytic properties of ACF for H2O2 production via the 2-e- O2 reduction, in turn increasing enalapril degradation by PEF. The effect of the current density on the mineralization of enalapril was evaluated and the highest TOC removal yield (80.5% in 3 h) was obtained at 8.33 mA cm-2, in the presence of 0.5 mmol L-1 of Fe2+ catalyst. Under those conditions, enalapril was totally removed within the first 10 min of treatment with a rate constant k = 0.472 min-1. In contrast, uncoated ACF only achieved 60% of TOC removal in 3 h at 8.33 mA cm-2. A degradation pathway for enalapril mineralization is proposed, based on the degradation by-products identified during treatment. Overall, the results demonstrate the promises of TiO2 cathodes for PEF, a strategy that has often been overlooked in favor of photoelectrocatalysis (PEC) based on TiO2-modified photoanodes.

Captopril to Lisinopril Conversion in Pediatric Cardiothoracic Surgery Patients Less Than 7 Years of Age (RISE-7)

Hypertension after cardiothoracic surgery is common, often requiring pharmacologic management. The recommended first-line antihypertensives in pediatrics are angiotensin converting enzyme inhibitors. Captopril and enalapril are approved for infants and children; however, lisinopril is only approved for > 7 years of age. This study evaluated safety and efficacy of converting from captopril to lisinopril in patients utilizing a pre-defined conversion of 3 mg captopril to 1 mg lisinopril. This was a single center, retrospective study including patients less than 7 years of age admitted for cardiothoracic surgery who received both captopril and lisinopril from 01/01/2017 to 06/01/2022.The primary outcome was mean change in systolic blood pressure (SBP) from baseline for 72 h after conversion of captopril to lisinopril. A total of 99 patients were enrolled. There was a significant decrease in mean SBP (99.12 mmHg vs 94.86 mmHg; p = 0.007) with no difference in DBP (59.23 mmHg vs 61.95 mmHg; p = 0.07) after conversion to lisinopril. Of the 99 patients who were transitioned to lisinopril, 79 (80%) had controlled SBP, 20 (20%) remained hypertensive, 13 (13%) received an increase in their lisinopril dose, and 2 (2%) required an additional antihypertensive agent. There was a low overall rate of AKI (3%) and hyperkalemia (4%) respectively. This study demonstrates that utilizing lisinopril with a conversion rate of 3 mg of captopril to 1 mg of lisinopril was safe and effective for controlling hypertension in pediatric patients following cardiothoracic surgery.

Obese Male Mice Exposed to Early Life Stress Display Sympathetic Activation and Hypertension Independent of Circulating Angiotensin II

BACKGROUND

We have previously reported that male mice exposed to maternal separation and early weaning (MSEW), a model of early life stress, show sympathetic activation and increased blood pressure in response to a chronic high-fat diet. The goal of this study was to investigate the contribution of the renin-angiotensin-aldosterone system to the mechanism by which MSEW increases blood pressure and vasomotor sympathetic tone in obese male mice.

METHODS AND RESULTS

Mice were exposed to MSEW during postnatal life. Undisturbed litters served as controls. At weaning, both control and MSEW offspring were placed on a low-fat diet or a high-fat diet for 20 weeks. Angiotensin peptides in serum were similar in control and MSEW mice regardless of the diet. However, a high-fat diet induced a similar increase in angiotensinogen levels in serum, renal cortex, liver, and fat in both control and MSEW mice. No evidence of renin-angiotensin system activation was found in adipose tissue and renal cortex. After chronic treatment with enalapril (2.5 mg/kg per day, drinking water, 7 days), an angiotensin-converting enzyme inhibitor that does not cross the blood-brain barrier, induced a similar reduction in blood pressure in both groups, while the vasomotor sympathetic tone remained increased in obese MSEW mice. In addition, acute boluses of angiotensin II (1, 10, 50 μg/kg s.c.) exerted a similar pressor response in MSEW and control mice before and after enalapril treatment.

CONCLUSIONS

Overall, elevated blood pressure and vasomotor sympathetic tone remained exacerbated in MSEW mice compared with controls after the peripheral inhibition of angiotensin-converting enzyme, suggesting a mechanism independent of angiotensin II.

Quality of care for patients with ST-segment Elevation Myocardial Infarction before COVID-19 pandemic in Cuba: review of 17 reports with 7823 patients

BACKGROUND

In Cuba, there is neither a registry of ST Elevation Myocardial Infarction (STEMI), nor are analysis of performance measures widely reported.

OBJECTIVE

A review of Cuban studies of patients with STEMI was carried out to describe quality of medical care.

METHODS

Cochrane Library, EMBASE, PubMed, Scopus and SciELO, as well as archives of national journals, were all searched for articles on STEMI in Cuba, from 2000 to March 2020. They were included if they reported number or percentage of application of reperfusion therapy; administration of aspirin, enalapril-captopril (ACEI) or beta-blockers; status of patients at discharge; and patient or system delay times. Finally, 17 reports with 7823 patients were included.

RESULTS

Thrombolytic therapy was administered to 3991 patients (51%), and 695 patients (8.9%) died. Only four studies, with 880 patients, presented data about prescription of ACEI, aspirin, and beta-blockers, which were administered to 381 (45.3%), 824 (93.6%), 464 (52.7%) patients, respectively. Coronary intervention was reported in 5 studies with 3422 patients, being performed in 661 (19.3%).  Conclusions: Quality of care of patients with STEMI seems to be poorer than reported in similar scenarios. Thrombolytic administration is still low, although mortality decreases in this period. Other pharmacological treatments were insufficiently fulfilled.

Medicine designed to combat diseases of affluence affects the early development of fish. How do plastic microparticles contribute?

The incidence of diseases of affluence, such as diabetes mellitus, cardiovascular diseases, high blood pressure, and high cholesterol has been reported to rise. Consequently, the concentrations of residues of drugs designed to treat these diseases have been rising in water bodies. Moreover, the toxicity of these pharmaceuticals towards fish and other non-target organisms can be even enhanced by microplastic particles that are reportedly present in surface water. Therefore, the aim of this study was to describe the effects of three highly prescribed drugs, in particular metoprolol, enalapril, and metformin on fish early-life stages. Also, it was hypothesized that polystyrene microparticles will increase the toxicity of metoprolol to fish early-life stages. Embryonal acute toxicity tests on Danio rerio and Cyprinus carpio were carried out in order to describe the possible toxic effects of metoprolol, enalapril, and metformin. Also, the acute toxicity of polystyrene microparticles and the combination of metoprolol with polystyrene microparticles were tested on D. rerio embryos. Additionally, a 31-day long embryo-larval subchronic toxicity test was carried out with C. carpio in order to describe the long-term effects of low concentrations of metoprolol. The results of the study show that both metoprolol and enalapril have the potential to disrupt the early development of the heart in the embryonal stages of fish. Also, enalapril and metformin together with polystyrene microparticles seem to possibly disrupt the reproduction cycle and act as endocrine disruptors. Both pure polystyrene microparticles and the combination of them with metoprolol affect inflammatory processes in organisms. Additionally, metformin alters several metabolism pathways in fish early-life stages. The results of the study bring new evidence that even low, environmentally-relevant concentrations of pharmaceuticals have the potential to disrupt the early development of fish, particularly on a molecular level.

Utilization patterns of cardiovascular medications in patients with diabetes mellitus; a retrospective cross-sectional study, 2013-17

BACKGROUND

Diabetes Mellitus (DM) is a prominent health care issue worldwide. One of the most prevalent comorbidities of DM is cardiovascular disease (CVD). The objective of this study was to assess the utilization patterns of cardiovascular medications in patients with DM in Iran from 2013 to 2017.

METHODS

This retrospective cross-sectional study was undertaken using prescription claims data from 2013 to 2017 in Iran. Epidemiological data elements used in this study were obtained from the Global Burden of Disease (GBD) 2019 study. In addition, data on total medication sales were obtained from the national regulatory authority database. The data on medication utilization were analyzed according to the Anatomical Therapeutic Chemical Classification (ATC) /Defined Daily Doses (DDD) international system.

RESULTS

Based on the findings, Acetylsalicylic acid was the mainstay of treatment with a utilization rate of 191.7 DDD/ patient/ year in 2017, followed by Atorvastatin with 170.0 and Losartan with 115.1. Although there was an increasing trend in the utilization rate of the medications, the rate of Atenolol and Enalapril was constantly declining during the 2013-17 period. On the other hand, Valsartan and Metoprolol were attracting attention. Almost all medication utilization rates increased from the 30-39 age group up to the 80 + age group. Females had a higher utilization rate in each age group during the whole study period.

CONCLUSION

The present study reflects that medication utilization patterns were rational, according to the standard treatment guidelines. Utilization patterns of medications that are recommended for both prevention and treatment of CVD in diabetes were observed to be the highest. Implementation of further policies is needed to minimize cardiovascular complications of diabetes.

Inhibition of angiotensin converting enzyme increases PKCβI isoform expression via activation of substance P and bradykinin receptors in cultured astrocytes of mice

BACKGROUND

Angiotensin-converting enzyme inhibitor (ACEi) inhibits the catalysis of angiotensin I to angiotensin II and the degradation of substance P (SP) and bradykinin (BK). While the possible relationship between ACEi and SP in nociceptive mice was recently suggested, the effect of ACEi on signal transduction in astrocytes remains unclear.

OBJECTIVES

This study examined whether ACE inhibition with captopril or enalapril modulates the levels of SP and BK in primary cultured astrocytes and whether this change modulates PKC isoforms (PKCα, PKCβI, and PKCε) expression in cultured astrocytes.

METHODS

Immunocytochemistry and Western blot analysis were performed to examine the changes in the levels of SP and BK and the expression of the PKC isoforms in primary cultured astrocytes, respectively.

RESULTS

The treatment of captopril or enalapril increased the immunoreactivity of SP and BK significantly in glial fibrillary acidic protein-positive cultured astrocytes. These increases were suppressed by a pretreatment with an angiotensin-converting enzyme. In addition, treatment with captopril increased the expression of the PKCβI isoform in cultured astrocytes, while there were no changes in the expression of the PKCα and PKCε isoforms after the captopril treatment. The captopril-induced increased expression of the PKCβI isoform was inhibited by a pretreatment with the neurokinin-1 receptor antagonist, L-733,060, the BK B1 receptor antagonist, R 715, or the BK B2 receptor antagonist, HOE 140.

CONCLUSIONS

These results suggest that ACE inhibition with captopril or enalapril increases the levels of SP and BK in cultured astrocytes and that the activation of SP and BK receptors mediates the captopril-induced increase in the expression of the PKCβI isoform.

The antihypertensive and diuretic effect of crude root extract and saponins from Solanum sisymbriifolium Lam., in L-NAME-induced hypertension in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Solanum sisymbriifolium Lam., is used in Paraguayan folk medicine claiming antihypertensive and diuretic properties.

AIM OF THE STUDY

This study aimed to determine the influence of chronic oral administration of the crude root extract and saponins obtained from S. sisymbriifolium Lam., on the blood pressure of male and female rats with hypertension induced by L-NAME, and its consequences on diuresis, the body weight, blood glucose, and level of serum parameters of liver and kidney functionality.

MATERIALS AND METHODS

Wistar rats were randomly divided into seven male, and seven female groups (8 animals each), which received as 6-week pretreatment, 0.9% saline solution (two groups; 0.1mL/10 g of b.w.), L-arginine (100.0 mg/kg/day), enalapril (15.0 mg/kg/day), crude extract (CESs 100.0 mg/kg/day), and saponin purified fraction (1.0, and 10.0 mg/kg/day), and treated with L-NAME (20 mg/kg/day/i.p.) twice, 1, and 6 h after pre-treatment. The animals' body weight, glycemia, and blood pressure were recorded weekly, while serum, hepatic, renal, and histological parameters were analyzed at the end of 6-week of treatment.

RESULTS

A protective effect of CESs (100.0 mg/kg/day), and saponins (1.0, and 10.0 mg/kg/day) against hypertension induced by L-NAME was verified in the systolic, diastolic, and mean blood pressure values, which were significantly lower than the positive L-NAME-hypertensive control group (male and female) at the end of the 6-week treatment. Also, pretreatment with enalapril (15.0 mg/kg/day) induced an efficient protective activity, which validates the method used. Likewise, the volume of urine, creatinine, uric acid, urea, and electrolyte excretion was enhanced at the end of 6-week of treatment in concordance with the reduction in serum level of the same parameters, compatible with the improvement of the diuretic activity. The glycemia, body weight, heart rate, and functional hepato-renal parameters were not modified after a 6-week of treatment, in comparison to the control group, indicating relatively acceptable harmless properties of CESs and saponins. Interestingly, the HDL level in females was increased in contrast to male rats by chronic saponins treatment when compared with the negative control group.

CONCLUSIONS

It can be concluded that either the increment in blood pressure (systolic, diastolic, and median) or cardiorenal remodeling effects in male and female rats submitted to L-NAME-induced hypertensive condition, were prevented and well-preserved without a significant variation during a period of 6-week of pretreatment with CESs and saponins pretreatments. Likewise, an important diuretic effect was revealed after this period of treatment.

Effect of the Renin-Angiotensin System Inhibitors on Inflammatory Markers: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To synthesize more conclusive evidence on the anti-inflammatory effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs).

METHODS

PubMed, Scopus, and Embase were searched from inception until March 1, 2021. We included randomized controlled trials (RCTs) that assessed the effect of ACEIs or ARBs, compared with placebo, on any of the following markers: C-reactive protein (CRP), interleukin 6 (IL-6), or tumor necrosis factor α (TNF-α). Mean changes in the levels of these markers were pooled as a weighted mean difference (WMD) with a 95% CI.

RESULTS

Thirty-two RCTs (n=3489 patients) were included in the final analysis. Overall pooled analysis suggested that ACEIs significantly reduced plasma levels of CRP (WMD, -0.54 [95% CI, -0.88 to -0.21]; P=.002; I²=96%), IL-6 (WMD, -0.84 [95% CI, -1.03 to -0.64]; P<.001; I²=0%), and TNF-α (WMD, -12.75 [95% CI, -17.20 to -8.29]; P<.001; I²=99%). Moreover, ARBs showed a significant reduction only in IL-6 (WMD, -1.34 [95% CI, -2.65 to -0.04]; P=.04; I²=85%) and did not significantly affect CRP (P=.15) or TNF-α (P=.97) levels. The lowering effect of ACEIs on CRP levels remained significant with enalapril (P=.006) and perindopril (P=.01) as well as with a treatment duration of less than 24 weeks (WMD, -0.67 [95% CI, -1.07 to -0.27]; P=.001; I²=94%) and in patients with coronary artery disease (WMD, -0.75 [95% CI, -1.17 to -0.33]; P<.001; I²=96%).

CONCLUSION

Based on this meta-analysis, ACEIs showed a beneficial lowering effect on CRP, IL-6, and TNF-α, whereas ARBs were effective as a class in reduction of IL-6 only.

Self-Perceived Psychological Stress and Risk of First Stroke in Treated Hypertensive Patients

OBJECTIVE

We aimed to investigate the prospective association between self-perceived psychological stress and first stroke, and to examine possible effect modifiers among adults with hypertension.

METHODS

A total of 20,688 hypertensive adults with information on self-perceived psychological stress at baseline were included from the China Stroke Primary Prevention Trial. Participants were randomly assigned to a double-blind treatment of receiving a single tablet daily with either 10 mg enalapril and 0.8 mg folic acid or 10 mg enalapril alone. Follow-up visits occurred every 3 months after randomization. Psychological stress was measured with a one-item 3-point rating scale. The primary outcome was first stroke (fatal or nonfatal).

RESULTS

The median treatment period was 4.5 years. Compared with participants with low levels of psychological stress, those with high psychological stress had a significantly higher risk of first stroke (adjusted hazard ratio = 1.40, 95% confidence interval = 1.01 to 1.94) or first ischemic stroke (adjusted hazard ratio = 1.45; 95% confidence interval = 1.01 to 2.09). Moreover, a stronger positive relationship between psychological stress and first stroke was found in participants with time-averaged mean arterial pressure <101 mm Hg (median; p-interaction = .004) during the treatment period. However, our study did not find a significant association between psychological stress and first hemorrhagic stroke.

CONCLUSIONS

Higher psychological stress was associated with an increased risk of first stroke among treated hypertensive patients, especially in those with lower mean arterial pressure during the treatment period.

Simultaneous determination of enalapril maleate and nitrendipine in tablets using spectrophotometric methods manipulating ratio spectra

A fixed dose combination of enalapril maleate (EN) and nitrendipine (NT) achieved satisfactory blood pressure control rather than monotherapy. Four accurate spectrophotometric methods utilizing ratio spectra were developed and validated for the simultaneous determination of EN and NT in combined pharmaceutical dosage form (Eneas® tablets). The first method was first derivative ratio spectrophotometric method (¹DD) where the amplitudes maxima were measured at 219.2 nm and 233.4 nm for the determination of EN and NT, respectively. The second method was ratio difference spectrophotometric method where EN and NT were estimated by measuring the amplitudes difference between 213 nm and 225 nm on the ratio spectrum of EN and between 241 nm and 227 nm on the ratio spectrum of NT. The third method was ratio subtraction followed by extended ratio subtraction, EN was determined at 210 nm by subtraction of the constant values from the ratio spectrum then multiplication with the divisor (NT spectrum). An extended ratio subtraction method was then applied in order to determine NT at 235 nm by using the zero-order spectrum of EN (10 μg/ml) as a divisor. The fourth method was ratio subtraction coupled with constant multiplication methods. The zero- order absorption spectrum of the laboratory prepared mixture was divided by NT (12 μg/ml) spectrum, subsequently, the value of the constant was multiplied by the divisor to obtain the original spectrum of NT, followed by its subtraction from the laboratory prepared mixture to get the spectrum of EN. EN and NT were determined at 210 nm and 235 nm, respectively. Linearity was ascertained over the concentration ranges of (1-11 μg/ml) for EN and (2-14 μg/ml) for NT, for the first and second methods and (2-13 μg/ml) for EN and (3-20 μg/ml) of NT, for the third and fourth methods. Application of the methods to the determination of the cited drugs in Eneas® tablets gave satisfactory results. Methods validation confirmed their accuracy and selectivity. Statistical comparison of the results with the reported one showed no significant difference, regarding precision and accuracy. Routine analysis of the cited drugs in quality control laboratories could be performed using the developed methods.

Sinergy between drugs and devices in the fight against sudden cardiac death and heart failure

The impact of sudden cardiac death (SCD) in heart failure (HF) patients is important and prevention of SCD is a reasonable and clinically justified endpoint if associated with a reduction in all-cause mortality. According to literature, in HF with reduced ejection fraction, only three classes of agents were found effective in reducing SCD and all-cause mortality: beta-blockers, mineralcorticoid receptor antagonists and, more recently, angiotensin-receptor neprilysin-inhibitors. In the PARADIGM trial that tested sacubitril/valsartan vs. enalapril, the 20% relative risk reduction in cardiovascular deaths obtained with sacubitril/valsartan was attributable to reductions in the incidence of both SCD and death due to HF worsening and this effect can be added to the known positive effect of implantable cardioverter-defibrillators in appropriately selected patients. In order to maximize the implementation of all the available treatments, patients with HF should be included in virtuous networks with a dialogue between all the physician involved, with commitment by all these physicians for appropriate decision-making on application of pharmacological and device treatments according to available evidence, as well as commitment for drug titration before and after device implant, taking advantage from remote monitoring, and with the safety of back up device therapy when indicated. There are potential synergistic effects of drug therapy, with all the therapies acting on neuro-hormonal and sympathetic activation, but specifically with sacubitril/valsartan, and device therapy, in particular cardiac resynchronization therapy, with added incremental benefits on positive cardiac remodelling, prevention of HF progression, and prevention of ventricular tachyarrhythmias.

"Permissive AKI" with treatment of heart failure

Renin-angiotensin-aldosterone system inhibitors have proven clinical benefit in management of patients with heart failure with reduced ejection fraction. However, there are no guidelines to manage decline in kidney function that occurs with initiation and titration of renin-angiotensin-aldosterone system agents during management of heart failure. We discuss the complex interplay of kidney function and heart failure in the presence of renin-angiotensin-aldosterone system agents and suggest a clinical algorithm for management of acute decline in kidney function.

BIOCHEMICAL AND MORPHOLOGICAL MARKERS OF EXPERIMENTAL SCOPOLAMINE-INDUCED NEURODEGENERATION AND THE EFFECT OF ENALAPRIL ON THEM

OBJECTIVE

The aim: Was to study enalapril effect on protein peroxide oxidation and lipids of the cerebral cortex and hippocampus of rats with neurodegeneration pattern.

PATIENTS AND METHODS

Materials and methods: The experiments were conducted on nonlinear albino male rats 0,18-0,20 kg of the body weight. Modeled neurodegeneration was simulated by intraperitoneal introduction of scopolamine hydrochloride during 27 days in the dose of 1 mg/kg. Enalapril was introduced intraperitoneal in the dose of 1 mg/kg.

RESULTS

Results: In rats with modeled scopolamine-induced neurodegeneration in the cerebral cortex and hippocampus under enalapril effect, the content of products, reacting with 2-thiobarbituric acid and proteins of a neutral and major character, decreases, which is indicative of a reduced intensity of lipid and protein peroxide oxidation. Morphologic the number of cells with karyopyknosis signs decreases and a relative staining density of the neuron tigroid substance increases, which is indicative of inhibition of the progress of the cerebral neurodestructive processes under conditions of scopolamine-induced damage.

CONCLUSION

Conclusions: The obtained results are indicative of enalapril ability to improve the examined indices, which is the evidence of increased processes of antioxidant protection and possibility to inhibit neurodegeneration development in case of scopolamine induced lesion of the brain.

[Novel Possibilities in Pharmacotherapy of Patients With Chronic Heart Failure]

In this article we have described clinical pharmacology and data of clinical studies of an innovational drug valsartan + sacubitril in patients with chronic heart failure (CHF). The use of supramolecular complex valsartan + sacubitril allows to elevate quality of life and improve prognosis of patients with CHF. High efficacy of valsartan+sacubitril relative to impact on composite primary end-point (cardiovascular death + hospitalization due to CHF) was demonstrated in the clinical trial PARADIGM-HF in which it was compared with angiotensin converting enzyme inhibitor enalapril. Advantages of the use of valsartan + sacubitril for the budget were demonstrated in pharmacoeconomic studies. These advantages are maximally realized at long-term administration. Cost-efficacy of the use of valsartan+sacubitril in pharmacotherapy of CHF is comparable with that of statins in the treatment of ischemic heart disease or implantation of a cardioverter-defibrillator in prevention of sudden cardiac death. Thus, introduction of the drug into practice can be expected to reduce budget expenditures.

Cardiovascular autonomic modulation by nitric oxide synthases accounts for the augmented enalapril-evoked hypotension in ethanol-fed female rats

In this study, we investigated the role of nitric oxide synthase (NOS) isoforms in the enhanced enalapril-evoked hypotension in ethanol-fed female rats by examining the effect of the selective inhibitors of eNOS [N(5)-(1-iminoethyl)-l-ornithine; l-NIO], nNOS (N(ω)-propyl-l-arginine; NPLA), or iNOS (1400W) inhibition on the cardiovascular effects of enalapril in ethanol- (5% w/v) fed rats and in their pair-fed controls. In liquid diet-fed control rats, enalapril- (10 mg/kg) evoked hypotension was abolished by l-NIO (20 mg/kg), but not by NPLA (1 mg/kg) or 1400W (5 mg/kg), suggesting a preferential role for eNOS in this response. Enalapril had no effect on spectral indices of hemodynamic variability or +dP/dtmax (myocardial contractility). However, in ethanol-fed rats, the greater enalapril-evoked hypotension was associated with reductions in (i) +dP/dtmax, (ii) low-frequency/high-frequency ratio of interbeat intervals (IBILF/HF), suggesting cardiac parasympathetic dominance, and (iii) low-frequency spectral band of systolic blood pressure (BP), a marker of vasomotor sympathetic tone. While NPLA or 1400W attenuated the enalapril-evoked hemodynamic and autonomic responses in ethanol-fed rats, l-NIO virtually abolished the hypotensive response and was more efficacious in rectifying autonomic responses to enalapril. Together, these findings implicate NOS isoforms, particularly eNOS, in the altered cardiovascular autonomic control that leads to the augmented enalapril-evoked hypotension in ethanol-fed female rats.

Total peripheral resistance responsiveness during the development of secondary renal hypertension in dogs

OBJECTIVE

To determine whether the responses of total peripheral resistance and arterial pressure to vasoconstrictor agents are amplified as renovascular hypertension develops in dogs.

METHODS

After baseline measurements, the effects of renal artery stenosis (1K, 1C hypertension) were studied in groups of untreated and enalapril-treated dogs early (1-3 weeks) and later (4-6 weeks) as the hypertension developed. Both resting and open-loop haemodynamic measurements were made and the effects of acute intravenous infusions of vasopressin (0.25, 0.5 and 1.25 ng/kg per min) and phenylephrine (0.125, 0.25 and 0.50 microg/kg per min on arterial pressure, cardiac output and calculated total peripheral resistance responses were measured.

RESULTS

Renal artery stenosis induced an increase in arterial blood pressure in both groups of dogs, with similar changes in haemodynamics also observed in open-loop conditions. The slopes of arterial pressure and peripheral resistance responses to vasopressin and phenylephrine were not significantly changed in early or late hypertension, in either the untreated or enalapril-treated groups.

CONCLUSIONS

Hypertension from renal artery stenosis in dogs was due to nonautonomic, nonangiotensin II mechanisms. There was no evidence of vascular amplification of the effects of vasoconstrictor agents, indicating that this did not play a role in the development of hypertension.

[Influence of long-term therapy with enalapril on late postinfarction remodeling and functional state of the left ventricle in patients with diastolic heart failure.]

Enalapril (average dose 7,0+/-0.8 mg) was given for 12 weeks to 15 patients with preserved left ventricular (LV) systolic function who had survived large focal myocardial infarction small i, Ukrainian6 months before that. The use of enalapril was associated with 49% lessening of severity of clinical signs of heart failure (p<0.001) and 47% increase of tolerance to physical exercise. It also provided dose dependent 17.8% reduction of LV myocardial mass (p<0.05), normalization of initially "hypertrophic" type of transmitral flow, 21% lowering of LV end diastolic pressure (p<0.05) without effect on LV volume, geometry, global and local systolic function.

Randomized, controlled study of the effects of losartan versus enalapril in small doses on proteinuria and tubular injury in primary glomerulonephritis

BACKGROUND

Pharmacological blockade of the renin-angiotensin-aldosteron system ameliorates glomerular and tubulointerstitial damage. For optimal renoprotection, high doses of angiotensin II converting enzyme inhibitors and angiotensin II subtype 1 receptor antagonists are commonly recommended, but cannot always be administered. The aim of this study was to evaluate the effects of low-dose (25 mg) losartan on proteinuria and tubular injury extent.

MATERIAL/METHODS

This was an open, randomized, 12-month study on the effects of 25 mg of losartan (n=19) vs. 10 mg of enalapril (n=14) as a control on proteinuria, urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG), and blood pressure in patients with primary glomerulonephritis. The second part of the study was an uncontrolled assessment of the renal effects of 50-mg administration of losartan.

RESULTS

There were no significant differences between the groups in the effects on proteinuria and NAG excretion. Losartan and enalapril reduced proteinuria by 32.8% (p<0.029) and 40.9% (p<0.021), respectively, but did not affect NAG excretion. The antiproteinuric effect of losartan, achieved without changes in blood pressure, was particularly evident in subjects with proteinuria >1.5 g/24 h and normal blood pressure. 50 mg of losartan caused a significant decrease in NAG excretion vs. the baseline (p<0.027).

CONCLUSIONS

25 mg of losartan and 10 mg of enalapril equally reduce proteinuria. The significant antiproteinuric effect of losartan was achieved despite no changes in blood pressure. There were no differences between the drugs regarding their influence on tubular injury extent. 50 mg of losartan seems to be the minimal dose to improve tubular status.

Interaction of noscapine with the bradykinin mediation of the cough response

Angiotensin Converting Enzyme Inhibitors (ACEI) like captopril and enalapril, can induce persistant cough in man. Noscapine, an antitussive alkaloid, can be used to suppress ACEI-induced cough. Some workers have suggested a role for bradykinin in precipitation of ACE-induced cough. Work carried out in our laboratory has shown noscapine to be a non-competitive inhibitor of bradykinin in guinea pig ileum. It is therefore possible that noscapine suppresses cough by blocking the effect of bradykinin receptor activation in the airways. Guinea pigs were placed in a cough-chamber connected to an air pump and a pressure transducer. Capsaicin was sprayed into the chamber and cough was recorded as a distinctive change in air pressure inside the cough-chamber. Animals treated with 1 mg/kg captopril and enalapril for 7 days, showed increased cough response. Ten microgram/kg FR190997, a non-peptide agonist of the bradykinin B2 receptor, also increased the cough response. Noscapine at 0.5, 1 and 2 mg/kg was able to reverse the effects of ACEI and FR190997. Naloxone, a specific opioid receptor inhibitor, did not block the antitussive effects of noscapine in enalapril or FR190997 treated guinea pigs. This antitussive effect of noscapine is not mediated via the mu, kappa or delta opioid receptors. It is therefore possible that noscapine exerts its antitussive action by interfering with the bradykinin cough mediation.

Renal function and angiotensin AT1 receptor expression in young rats following intrauterine exposure to a maternal low-protein diet

Recent studies have proposed a link between impaired nephrogenesis, decreased activity of the renin-angiotensin system and the onset of hypertension in rats exposed in the uterus to a maternal low-protein diet. However, there is no detailed information about renal function in this model; hence the aim of the present study was to assess renal function in young (4-week-old) rats exposed in the uterus to a maternal low-protein diet. Pregnant Wistar rats were fed isocalorific diets containing either 18% (normal protein; offspring denoted NP rats) or 9% (low protein; offspring denoted LP rats) (w/w) protein from conception until birth. At 4 weeks of age, male offspring were anaesthetized and prepared for the study of renal function, during which animals received saline alone, a bolus of enalapril (5 mg.kg(-1)) or a bolus of enalapril followed by an infusion of angiotensin II (30 ng.min(-1).kg(-1)). Under control conditions, renal haemodynamic and tubular function did not differ. However, when challenged with angiotensin II, LP rats responded with a greater decrease in glomerular filtration rate than did NP rats [NP, 2.0+/-0.2 ml.min(-1).g(-1) kidney weight ( n =9); LP, 1.0+/-0.2 ml.min(-1).g(-1) kidney weight ( n =5); P <0.05]. Renal electrolyte excretion did not differ. LP rats had significantly fewer glomeruli than NP rats ( P <0.01). Renal angiotensin II AT(1) receptor expression was increased ( P <0.01) by 24% in LP rats. It is concluded that blood pressure may be elevated in LP rats in order to maintain glomerular filtration rate against a background of fewer nephrons. Increased AT(1) receptor expression, which may arise as a result of the direct effect of protein restriction or in response to the reported decrease in renal tissue angiotensin II concentration, could also contribute to the elevated blood pressure of this model.

[Theoretical model of a cost-effectiveness analysis of combined enalapril-nitrendipine therapy for treating hypertension]

OBJECTIVE

Cost-effectiveness analysis of combined enalapril-nitrendipine therapy (E/N), as second-line therapy for light or moderate hypertension.

DESIGN

Theoretical model of cost-effectiveness, based on the norms of hypertension treatment in primary care, the considered view of a panel of experts and the direct costs of health resources and purchase of medication.

SETTING

Spanish National Health system.

PARTICIPANTS

Simulation of 1000 patients with hypertension, with a time horizon of one year.

INTERVENTIONS

After a prior failure of the first-line treatment with either enalapril or nitrendipine, an evaluation was made of the possibilities of increasing dosage of the first-line treatment, changing the drug or administering the E/N combination.

MAIN MEASUREMENT

The likelihoods, in the primary care context, of controlling diastolic pressure, of abandonment and of using the two strategies or not were measured, as were the use of health resources in each situation, and costs of resource use and of medication.

RESULTS

The cost-effectiveness quotient of the combined E/N treatment was consistently more efficient than the increase in dose or change to another drug. This was so, whether the treatment was started with enalapril (301.06 euros vs 337.97 euros and 588.42 euros) or with nitrendipine (331.5 euros vs 469.88 euros and 579.76 euros).

CONCLUSIONS

Combined therapy (E/N) is, on the basis of the assumptions made in the model, an efficient therapy option. Therefore, it can be recommended for prescription.

Efficacy of domestic bisoprolol,enalapril and nifedipine retard in mild to moderate hypertension: a randomized double-blind multicenter clinical trial in China

OBJECTIVE

To compare the efficacy and tolerability of bisoprolol, enalapril and nifedipine retard in the treatment of mild to moderate essential hypertension.

METHODS

This is a randomized, double-blind, multicenter clinical trial. 331 patients with mild to moderate hypertension in the army troop were randomly allocated to receive domestic bisoprolol ( n =110,5 mg/d),enalapril ( n =111,10 mg/d) and nifedipine retard ( n =110,20 mg/day). Total duration of active drug treatment was 4 weeks.

RESULTS

The total efficacy rates of domestic bisoprolol, enalapril and nifedipine retard were 80.0%, 82.0% and 81.8% respectively P > 0.05 . The incidences of adverse events were 4.5%, 8.1% and 19.1% (P < 0.01 ) in patients of bisoloprol, enalapril and nifedipine retard groups respectively. The adverse effects were mild in all the three groups.

CONCLUSIONS

Domestic bisoprolol, enalapril and nifedipine retard are effective and well-tolerated in patients with mild to moderate essential hypertension. The occurrence of adverse effects were least in the bisoprolol group and most in the nifedipine retard group.

Dermatitis to captopril

BACKGROUND

reports on delated cutaneous reactions to captopril have been seldom reported. Captopril is an angiotensin-converting enzyme (ACE) inhibitor and their cutaneous side-effects are documented, but little has been published concerning the usefulness of patch test when they occur. We presented the case of a patient who developed a cutaneous reaction induced by captopril with positive patch test.

METHODS AND RESULTS

patch testing was performed with captopril, other ACE (enalapril, lisinopril ramipril), and European standard series. Following, we performed a double-blind oral challenge test with drugs who results was negative. Positive reaction were obtained to captopril at 4 days and the others test being negative. The same test were negative in five control patients. The patient tolerated enalapril, and lisinopril without problems.

CONCLUSION

the allergological studies confirmed sensitisation to captopril and tolerance to lisinopril, and enalapril. When patch test are performed with several drugs of the same family, results seem to indicate an absence of cross-sensitivity, but in several patients, oral provocation test were needed because patch test gave no conclusive information.

Effect of profound normovolemic hypotension and moderate hypothermia on circulating cytokines and adhesion molecules

Hypotension caused by hypovolemic, hemorrhagic shock induces disturbances in the immune system that may contribute to an increased susceptibility to sepsis. The effect of chemically induced hypotension on circulating cytokines and adhesion molecules has not been investigated yet. In 21 patients scheduled for resection of malignant choroidal melanoma of the eye the perioperative serum levels of the cytokines IL-1beta, IL-6, IL-10, TNF-alpha, and the adhesion molecules sE-Selectin and sICAM-1 were investigated. Moderate hypothermia of 32 degrees C was induced in all patients. In 14 patients profound hypotension (mean arterial blood pressure 35-40 mmHg, hypotension group) was induced by enalapril and nitroglycerin for a mean duration of 71 min. In 7 patients the tumor was not resectable, and hypotension was not induced (controls). We did not detect significant differences in serum levels of cytokines or sE-Selectin perioperatively in patients with profound hypotension compared with controls. In both groups IL-6 serum levels increased significantly and reached a maximum after rewarming (17 +/- 6 and 16 +/- 5 pg/dL, respectively, P < 0.001). IL-1beta, IL-10, and TNF-alpha did not change perioperatively in both groups. On the first postoperative day sICAM-1 serum levels were significantly increased in both groups (mean increase of 96 and 54 ng/mL, respectively, P < 0.01 and P < 0.05). We conclude from this study that profound normovolemic arterial hypotension does not seem to have effects on serum levels of circulating IL-1beta, IL-6, IL-10, TNF-alpha, and sE-Selectin. Perioperative moderate hypothermia may be the reason for the postoperative increase in sICAM-1 levels independent of the blood pressure.

Search for related substances in market products containing enalapril maleate as the active principle

This study's main object was the determination of substances, by means of high-performance liquid chromatography (HPLC), that are related to enalapril maleate in medicinal tablets. The research was on products containing a 20 mg active principle with a 12-month delta t and on those batches near their expiration date with an enalapril maleate concentration of 10, 5, and 2.5 mg.

False-positive result of a captopril-enhanced radionuclide renogram in a child secondary to dehydration

PURPOSE

Renovascular hypertension is an unusual cause of elevated mean arterial pressure in children. When suspected, angiotensin-converting enzyme inhibitor-enhanced renal scintigraphy is usually one of the initial studies done to evaluate patients. The accuracy of this test depends not only on patient selection but also on technical factors involved in performing the study. We report a case of a false-positive angiotensin-converting enzyme inhibitor-enhanced radionuclide renogram in a 5-year-old boy with hypertension.

METHODS

Angiotensin-converting enzyme inhibitor-enhanced renal scintigraphy was performed and the result was interpreted as positive for bilateral renovascular disease. A review of the anesthesia record from the study revealed that the patient was hypotensive. A repeated study with adequate hydration and blood pressure stability was then done.

RESULTS

The result of the second examination was interpreted as normal, without evidence of abnormal renovascular physiology.

CONCLUSIONS

The cause of the initial false-positive result was determined to be dehydration with secondary hypotension. Dehydration, with secondary hypotension, can cause a diminished glomerular filtration rate and mimic bilateral renovascular physiology on angiotensin-converting enzyme inhibitor-enhanced renal scans.

Enalapril plus frusemide MAG3 scintigraphy in hypertensive patients with atherosclerosis and moderate renal insufficiency

We performed a retrospective study on 26 patients with moderate renal failure (mean GFR = 51 +/- 21 ml min-1 1.73 m-2), hypertension and atherosclerosis. Apart from three patients who had completely normal renal Doppler ultrasonography, all patients underwent renal angiography. Three groups of kidneys with different atherosclerotic renal artery involvement were identified: Group 1, 24 kidneys with no renal artery stenosis (RAS); Group 2, 18 kidneys with mild (> 25% and < 50% diameter) RAS; and Group 3, 10 kidneys with moderate (> 50% diameter) RAS. We used a two-day protocol with frusemide plus enalapril 99Tcm-MAG3 scintigraphy. The mean parenchymal transit time (MPTT), time to the maximum activity (time to peak) of the renal curve (Tmax), residual activity and split renal uptake were evaluated. The measured parameters did not differ before and after enalapril in Group 1 or in Group 2. In Group 3, MPTT and residual activity differed significantly (P < 0.025) before and after enalapril. The Tmax before and after enalapril, MPTT before and after enalapril and residual activity after enalapril differed significantly (P < 0.05) between Groups 1 and 3 and between Groups 2 and 3. Threshold values were obtained to maximize diagnostic accuracy. The Tmax, MPTT and residual activity after enalapril gave satisfactory results, and MPTT performed best with a 75% positive predictive value and a 98% negative predictive value for the diagnosis of renal artery stenosis. We conclude that MPTT, measured after enalapril administration, is a useful parameter to detect renal artery stenosis in patients with hypertension, atherosclerosis and moderate renal insufficiency.

NaCl appetite in two strains of rat reported to be resistant to mineralocorticoid-induced hypertension

Both Long-Evans (LE) and Wistar-Furth (WF) strains of rat are known to be resistant to development of hypertension by mineralocorticoid (MC) treatment. MC-induced hypertension is, in part, mediated by the brain. We have examined another aspect of central MC action, the induction of NaCl appetite in these strains, by using the more common Sprague-Dawley (SD) and Wistar (WS) strains for comparison. In the first experiment, LE and SD rats were administered three treatments known to induce an appetite for NaCl solution in rats. Administration of deoxycorticosterone acetate (DOCA) increased the intake of 0.45 M NaCl in both strains, but the amounts consumed were about 2-fold greater in LE rats than in SD rats. Administration of captopril also increased NaCl intake, but there were no differences between LE and SD rats. NaCl depletion with furosemide induced NaCl appetite in both strains, but the amounts consumed were about 2-fold greater in LE rats than in SD rats. In the second experiment, adult male WF and WS rats were administered DOCA, enalapril, or furosemide and NaCl appetite was determined. Both strains showed comparable NaCl appetite during each of these treatments. However, during a 5-week regimen of DOCA with only NaCl-KCl solution to drink, uninephrectomized WF rats consumed less than WS rats. Thus, despite reported resistance to MC-induced hypertension, neither LE nor WF strains of rats showed correspondingly marked deficits in induced NaCl appetite.

Reliability of ACE inhibitor-enhanced 99Tcm-DTPA gamma camera renography in the detection of renovascular hypertension

Twenty consecutive patients with renovascular hypertension, proven by cure or improvement of hypertension at 1-year follow-up after percutaneous transluminal angioplasty or surgical repair, were studied before intervention by means of gamma camera renography with 99Tcm-diethylenetriaminepentaacetic acid (99Tcm-DTPA) at baseline and after angiotensin-converting enzyme (ACE) inhibition. Sixteen patients underwent bilateral renal vein catheterization for measurement of renal vein renin release and extraction ratios of para-amino-hippurate (PAH) and 51Cr-EDTA before and after acute ACE inhibition. With the limit for a significant change in relative side distribution of 5% or more after ACE inhibition on gamma camera renography 13 patients responded (Group 1), while seven patients (Group 2) had unchanged side distribution. Glomerular filtration rate (GFR), measured with 99Tcm-DTPA, in the affected kidney decreased in Group 1 from 26 +/- 16 ml min-1 to 11 +/- 12 ml min1 (P < 0.0005), while GFR was unchanged in the affected kidney in Group 2, 26 +/- 13 ml min-1 versus 29 +/- 13 ml min-1. Extraction ratios of PAH and 51Cr-EDTA for the affected kidney in Group 1 decreased from 80 +/- 18 to 73 +/- 21% (P < 0.05) and from 16 +/- 5 to 7 +/- 5% (P < 0.005), respectively, while in Group 2 the PAH extraction ratio was not significantly changed, 86 +/- 5 versus 81 +/- 14%, but the 51Cr-EDTA extraction ratio for the affected kidney also decreased from 16 +/- 3 to 8 +/- 4% (P < 0.005). All patients had lateralization of renal vein renin to the affected kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Possible interaction between SPPS and enalapril

A patient undergoing groin lymph node dissection with spinal and general anaesthesia was receiving enalapril to control hypertension. Infusion of stable plasma protein solution (Commonwealth Serum Laboratories, Australia) was associated with significant hypotension and flushing. A brief review of stable plasma protein solution and angiotensin converting enzyme inhibitor pharmacology is presented to provide a possible mechanism for these events. This mechanism implies that angiotensin converting enzyme inhibitor therapy is a relative contraindication to rapid SPPS infusion.

Diagnostic use of angiotensin converting enzyme inhibitors in radioisotope evaluation of unilateral renal artery stenosis

Iodine-123 hippurate renography, [99mTc]diethylenetriaminepentaacetic acid (DTPA) renography, and [99mTc]dimercapto succinic acid (DMSA) renal scintigraphy were performed before and during angiotensin converting enzyme (ACE) inhibition in a group of 15 hypertensive patients with angiographically "significant" unilateral renal artery stenosis. Visual and quantitative evaluation of the three radioisotope methods before ACE inhibition already disclosed abnormalities suggestive of renal artery stenosis in a high percentage (87%, 60%, and 60%, respectively) in this group of patients, but ACE inhibition further improved the diagnostic yield in all three methods (93%, 86%, and 80%). Iodine-123 hippurate renography was at least as useful as [99mTc]DTPA renography in this respect, while [99mTc]DMSA scintigraphy can be used particularly in segmental stenosis. Despite a large drop in blood pressure after ACE inhibition little adverse reactions were seen and overall renal function was fairly well maintained, the exceptions noted in patients with initially a more impaired renal function.

Acute and long-term renal effects of angiotensin converting enzyme inhibition in normotensive, normoalbuminuric insulin-dependent diabetic patients

Glomerular filtration rate (GFR) (thalamate clearance), renal plasma flow (RPF) (hippuran clearance), and urinary albumin excretion rate (AER) were measured in 10 normoalbuminuric, normotensive insulin-dependent diabetic patients and 8 normal subjects before and during acute angiotensin converting enzyme (ACE) inhibition by means of enalapril (10 mg IV). The effect of placebo versus enalapril (30 mg day-1) was also studied for 3-month treatment periods in the insulin-dependent diabetic patients. Acute ACE-inhibition caused a decline in filtration fraction (FF) from 0.259 +/- 0.011 (+/- SE) to 0.237 +/- 0.013 (2p less than 0.01) in the diabetic patients, and from 0.210 +/- 0.010 to 0.188 +/- 0.006 (2p less than 0.02) in the normal subjects. Mean arterial blood pressure was lowered from 90 +/- 1 to 84 +/- 2 mmHg (2p less than 0.01) and from 91 +/- 1 to 86 +/- 2 mmHg (2p less than 0.05). No significant change in blood glucose, AER or fractional albumin excretion (theta Alb) was seen in either group. After 3 months of enalapril treatment FF was decreased from 0.253 +/- 0.011 to 0.235 +/- 0.011 (2p less than 0.05), AER from 5.6 x/ divided by 1.7 to 4.3 x/divided by 1.6 micrograms min-1 (2p less than 0.01) and theta Alb from 1.22 +/- 0.22 x 10(-6) to 0.92 +/- 0.12 x 10(-6) (2p less than 0.02). The decline in total renal resistance was not significant (0.175 +/- 0.013 to 0.165 +/- 0.012 mmHg ml-1 min-1) and significant changes in GFR, RPF, mean arterial pressure or HbA1c were not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro renin inhibition to prevent generation of angiotensins during determination of angiotensin I and II

To prevent in vitro generation of angiotensins, the renin inhibitor CGP 29287 (CGP) was added to blood sampling tubes. Plasma immunoreactive angiotensin (ir-ANG) I and II were simultaneously measured by radioimmunoassay after rapid and quantitative extraction from a single plasma sample on phenylsilylsilica (Bondelut PH). True plasma ANG-(1-8)octapeptide was determined after additional separation of the different angiotensins by high performance liquid chromatography. Ir-ANG II/CGP showed the known linear relationship with ANG-(1-8)octapeptide (r = 0.87, n = 23), but - in contrast to studies without addition of CGP - the y-axis intercept which presumably represents cross-reacting angiotensins other than ANG II was very small. Ir-ANG II/CGP concentrations fell below 1 fmol/ml after converting enzyme inhibition. The results suggest that CGP 29287 prevents in vitro generation of ANG I and ANG II as well as the ANG-metabolites. Ir-ANG I/CGP measured after Bondelut PH extraction of the plasma was strongly correlated with ir-ANG I obtained after blood ethanol extraction (r = 0.97, n = 23). Thus, it is now possible to measure reliably both ANG I and ANG II within the same plasma extract after a simple extraction procedure.

Effect of enalapril on ventricular arrhythmias in congestive heart failure

Twenty-four-hour Holter electrocardiographic recordings were used to measure the effects of a converting-enzyme inhibitor, enalapril, given for 12 weeks, on the frequency of cardiac arrhythmias in 10 patients with congestive heart failure (New York Heart Association functional class II to III) receiving maintenance therapy with digoxin and furosemide. Nine patients were given placebo, and both study groups were conducted in a double-blind, parallel manner. The placebo group had no change in the frequency of arrhythmias, whereas enalapril-treated patients showed a significant decrease in the frequency of premature ventricular complexes, ventricular couplets and ventricular tachycardia. A minor, nonsignificant reduction in atrial premature complexes was seen in patients who received enalapril. Compared with placebo patients, those who received enalapril had an increase in plasma potassium levels of 0.33 mmol/liter, a decrease in plasma digoxin, and decreases in pulmonary artery wedge, mean pulmonary artery and right atrial pressures. However, none of these indexes were correlated with the concomitant decline in cardiac arrhythmias. It is concluded that enalapril reduces the frequency of ventricular arrhythmias in congestive heart failure, although the underlying mechanisms are not known.

Control of glomerular hypertension limits glomerular injury in rats with reduced renal mass

Micropuncture and morphologic studies were performed in four groups of male Munich-Wistar rats after removal of the right kidney and segmental infarction of two-thirds of the left kidney. Groups 1 and 3 received no specific therapy. Groups 2 and 4 were treated with the angiotensin I converting enzyme inhibitor, enalapril, 50 mg/liter of which was put in their drinking water. All rats were fed standard chow. Groups 1 and 2 underwent micropuncture study 4 wk after renal ablation. Untreated group 1 rats exhibited systemic hypertension and elevation of the single nephron glomerular filtration rate (SNGFR) due to high average values for the mean glomerular transcapillary hydraulic pressure difference and glomerular plasma flow rate. In group 2 rats, treatment with enalapril prevented systemic hypertension and maintained the mean glomerular transcapillary hydraulic pressure gradient at near-normal levels without significantly compromising SNGFR and the glomerular capillary plasma flow rate, as compared with untreated group 1 rats. Groups 3 and 4 were studied 8 wk after renal ablation. Untreated group 3 rats demonstrated persistent systemic hypertension, progressive proteinuria, and glomerular structural lesions, including mesangial expansion and segmental sclerosis. In group 4 rats, treatment with enalapril maintained systemic blood pressure at normal levels over the 8-wk period and significantly limited the development of proteinuria and glomerular lesions. These studies suggest that control of glomerular hypertension effectively limits glomerular injury in rats with renal ablation, and further support the view that glomerular hemodynamic changes mediate progressive renal injury when nephron number is reduced.

Acute and long-term effects of enalapril on the cardiovascular response to exercise and exercise tolerance in patients with congestive heart failure

Enalapril is a recently developed angiotensin-converting enzyme inhibitor that improves cardiac function at rest in patients with congestive heart failure. This study investigated the acute effects of enalapril on the cardiovascular response to exercise, and then evaluated the long-term effects of enalapril on exercise capacity and functional status during a 12 week placebo-controlled trial in patients with heart failure. Ten patients underwent hemodynamic monitoring while at rest and during incremental bicycle exercise before and after 5 to 10 mg of enalapril orally. At rest, enalapril decreased mean blood pressure 13% (p less than 0.01) and systemic vascular resistance 20% (p less than 0.05) and increased stroke volume index 21% (p less than 0.01). During maximal exercise, enalapril decreased systemic vascular resistance and increased both cardiac and stroke volume indexes. Enalapril acutely increased exercise duration (p less than 0.05) and maximal oxygen consumption (p less than 0.001). These 10 patients and an additional 13 patients were then randomized to either placebo or enalapril treatment and followed up for 12 weeks. Of the 11 patients assigned to active treatment, 73% considered themselves improved compared with 25% of the patients assigned to placebo treatment (p less than 0.02). During long-term treatment, exercise capacity increased in patients receiving enalapril (p less than 0.001) but was unchanged in patients receiving placebo (intergroup difference, p less than 0.05). During long-term treatment, no adverse effects of enalapril occurred. Thus, enalapril improves cardiac function at rest and during exercise. Compared with placebo, maintenance therapy with enalapril results in symptomatic improvement and increased exercise capacity.

Temporal relationships of treatment with angiotensin converting enzyme inhibitors on the hypertension and cardiac hypertrophy in spontaneously hypertensive rats

Two groups of spontaneously hypertensive rats (SHRs) were treated with captopril and enalapril, respectively. Treatment was started at weaning and at 8 months of age. Blood pressure was maintained close to normal in rats treated from weaning and significantly lowered but not to normal levels in rats started on treatment at 8 months. The long-term treated rats did not show significant cardiac enlargement whereas those treated at 8 months had an increase in cardiac size although not to the same level as untreated animals. Treatment with minoxidil and minoxidil plus propranolol similarly lowers blood pressure, but does not reduce myocardial hypertrophy. The data confirm that both the time of onset of treatment as well as the type of drug influence the myocardial complications of hypertension in SHRs. These studies further demonstrate the use of the SHR as a model for clinical pharmacologic studies with antihypertensive agents.

Effective dose range of enalapril in mild to moderate essential hypertension

The dose-response relationship of enalapril was evaluated in a double-blind, balanced, two-period, incomplete-block study in 91 patients with mild to moderate essential hypertension. Patients were randomly assigned to two of six treatments: placebo, 2.5, 5, 10, 20 and 40 mg/day of enalapril maleate. There were two 3-week treatment periods, each preceded by a 4-week, single-blind placebo washout. Each dose of enalapril produced significant decreases in standing and supine systolic and diastolic blood pressure after 2 and 3 weeks of treatment. There were no significant changes on placebo. There was a significant linear dose response relationship for both mean blood pressure and mean change from baseline in blood pressure (P less than 0.01 for systolic and mean arterial pressure, and P less than 0.05 for diastolic pressure). Enalapril was associated with an increasing dose-response relationship across the 2.5-40 mg/day range. The 2.5 mg/dose is effective in some patients; however, doses greater than or equal to 10 mg/day may be necessary to achieve satisfactory blood pressure control.