Angiotensin-converting enzyme inhibitors

Renal effects of canagliflozin in type 2 diabetes mellitus

BACKGROUND

Chronic kidney disease is commonly associated with type 2 diabetes mellitus (T2DM) and may impact the efficacy and safety of glucose-lowering therapies. Canagliflozin, a sodium glucose co-transporter 2 inhibitor, reduces blood glucose levels in patients with T2DM by lowering the renal threshold for glucose, thereby promoting urinary glucose excretion. This review describes the pharmacology, efficacy and safety of canagliflozin according to kidney function in participants with T2DM.

METHODS

Published articles that reported efficacy, safety and pharmacokinetics/pharmacodynamics data for canagliflozin in patients with T2DM and impaired renal function, and renal safety data with canagliflozin in various populations of patients with T2DM through May 2015 were included.

RESULTS

Early transient reductions in estimated glomerular filtration rate were observed with canagliflozin; these changes generally stabilized or attenuated over time and reversed after discontinuation, suggesting no renal (glomerular or tubular) damage with canagliflozin treatment. Urinary albumin-to-creatinine ratios were reduced with canagliflozin. Canagliflozin was generally well tolerated in patients with normal or mild to moderately impaired renal function, with a modestly higher incidence of renal-related adverse events and volume depletion-related adverse events in patients with moderate renal impairment. Adverse events related to potassium elevations were infrequent with canagliflozin 100 mg regardless of kidney function status; however, patients with moderately impaired kidney function experienced hyperkalemia more frequently with canagliflozin 300 mg compared with patients treated with either canagliflozin 100 mg or placebo. Canagliflozin was not associated with increased cardiovascular risk across studies; however, relatively few events among patients with impaired renal function meant that the analysis was not adequately powered to examine this outcome, and results from separate trials are awaited.

CONCLUSIONS

Overall, canagliflozin is associated with small, transient changes in kidney function, and is well tolerated in patients with T2DM with varying kidney function status.

Isolated Visceral Angioedema Induced by Angiotensin-Converting Enzyme Inhibitor

Visceral angioedema is a rare complication of therapy with angiotensin-converting enzyme (ACE) inhibitors. Clinical presentation includes nausea, vomiting, abdominal pain and diarrhea. Early detection of this entity can prevent recurrent episodes and unnecessary invasive procedures, including surgery.

This article describes a 46-year-old-woman who presented to the emergency department with abdominal pain, associated with nausea and vomiting. She had been taking ramipril for 15 days.

A computed tomography was performed which revealed thickening of a jejunal segment, with submucosal edema.

ACE inhibitor-associated angioedema was suspected and the medication was discontinued, with resolution of symptoms in 48 h.

After 7 months of follow-up, the patient is asymptomatic.

Despite of its rarity, ACE inhibitor-induced small-bowel angioedema should be included in the differential diagnosis when patients receiving ACE inhibitor therapy present with abdominal complaints.

Foundations of Pharmacotherapy for Heart Failure With Reduced Ejection Fraction: Evidence Meets Practice, Part I

Pharmacologic treatment for systolic heart failure, otherwise known as heart failure with reduced ejection fraction, has been established through clinical trials and is formulated into guidelines to standardize the diagnosis and treatment. The premise of pharmacologic therapy in heart failure with reduced ejection fraction is aimed primarily at interrupting the neurohormonal cascade that is responsible for altering left ventricular shape and function. This is the first in a series of articles to describe the pharmacologic agents in the guidelines that impact the morbidity and mortality associated with heart failure. Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and vasodilators will be presented in the context of the mechanism of action in heart failure, investigational trials that showed beneficial effects, and the practical application for clinical use.

Comparative Effect of Lisinopril and Fosinopril in Mitigating Learning and Memory Deficit in Scopolamine-Induced Amnesic Rats

Lisinopril and fosinopril were compared on scopolamine-induced learning and memory deficits in rats. A total of eighty-four male Wistar rats were divided into seven groups. Group I received 2% gum acacia orally for 4 weeks, group II received normal saline, and group III received scopolamine (2 mg/kg/ip) as single dose. Groups IV and V received lisinopril ( 0.225 mg/kg and 0.45 mg/kg), while Groups VI and VII received fosinopril (0.90 mg/kg and 1.80 mg/kg), respectively, orally for four weeks, followed by scopolamine (2 mg/kg/ip) given 45 minutes prior to experimental procedure. Evaluation of learning and memory was assessed by using passive avoidance, Morris water maze, and elevated plus maze tests followed by analysis of hippocampal morphology and quantification of the number of surviving neurons. Scopolamine induced marked impairment of memory in behavioral tests which correlated with morphological changes in hippocampus. Pretreatment with fosinopril 1.80 mg/kg was found to significantly ameliorate the memory deficits and hippocampal degeneration induced by scopolamine. Fosinopril exhibits antiamnesic activity, indicating its possible role in preventing memory deficits seen in dementia though the precise mechanism underlying this effect needs to be further evaluated.

Antioxidation, angiotensin converting enzyme inhibition activity, nattokinase, and antihypertension of Bacillus subtilis (natto)-fermented pigeon pea

Because of the high incidence of cardiovascular diseases in Asian countries, traditional fermented foods from Asia have been increasingly investigated for antiatherosclerotic effects. This study investigated the production of nattokinase, a serine fibrinolytic enzyme, in pigeon pea by Bacillus subtilis fermentation. B. subtilis 14714, B. subtilis 14715, B. subtilis 14716, and B. subtilis 14718 were employed to produce nattokinase. The highest nattokinase activity in pigeon pea was obtained using B. subtilis 14715 fermentation for 32 hours. In addition, the levels of antioxidants (phenolics and flavonoids) and angiotensin converting enzyme inhibitory activity were increased in B. subtilis 14715-fermented pigeon pea, compared with those in nonfermented pigeon pea. In an animal model, we found that both water extracts of pigeon pea (100 mg/kg body weight) and water extracts of B. subtilis-fermented pigeon pea (100 mg/kg body weight) significantly improved systolic blood pressure (21 mmHg) and diastolic blood pressure (30 mmHg) in spontaneously hypertensive rats. These results suggest that Bacillus-fermented pigeon pea has benefits for cardiovascular health and can be developed as a new dietary supplement or functional food that prevents hypertension.

Change in prescription pattern as a potential marker for adverse drug reactions of angiotensin converting enzyme inhibitors

Background Angiotensin converting enzyme inhibitors (ACEIs) are among the most frequently prescribed groups of medications. ACEI-induced adverse drug reactions (ADRs) are the main reason to discontinue or switch ACEI treatment. ADRs information is not available in prescription databases. Objective To identify a proxy for ACEI-induced ADRs in prescription databases. Setting The Rotterdam Study is an ongoing prospective cohort study that started in 1990 in the Netherlands and has included 14,926 subjects aged 45 years or older. Methods All ACEI starters from 2000 to 2011 were identified using prescription data within the Rotterdam Study. Participants were classified into 4 mutually exclusive groups: continuing, discontinuing, switching to angiotensin receptor blockers (ARBs), and switching to other antihypertensives. For categorization, the maximum time-interval between two prescription periods was set at 3 and 6 months. Subsequently, primary care physician files were searched and clinical events were classified as definite ADRs, probable ADRs, possible ADRs and definite non-ADRs. Finally the accuracy of different prescription patterns as indicators of ADRs was evaluated. Main outcome measure Positive predictive values (PPVs), negative predictive values (NPVs), sensitivity and specificity of the prescription patterns of the 4 groups were calculated. Results Totally, 1132 ACEI starters were included. The PPV for a definite ADR was 56.1 % for switchers to ARB, while the PPVs for switchers to other antihypertensives, and discontinuation were 39.5 and 19.5 %, respectively. After including probable ADRs and possible ADRs, PPVs for switchers to ARB increased to 68.3 and 90.5 %. A 6-month interval gave slightly higher PPVs compared to a 3-month interval (maximum 6.1 % higher). The differences in NPVs between 3 and 6-months interval groups were approximately 1.0 %. Conclusions Switching ACEIs to ARBs is the best marker for ACEI-induced ADRs in prescription databases.

Local Augmented Angiotensinogen Secreted from Apoptotic Vascular Endothelial Cells Is a Vital Mediator of Vascular Remodelling

Vascular remodelling is a critical vasculopathy found in atheromatous diseases and allograft failures. The local renin angiotensin system (RAS) has been implicated in vascular remodelling. However, the mechanisms by which the augmented local RAS is associated with the initial event of endothelial cell apoptosis in injured vasculature remain undefined. We induced the apoptosis of human umbilical vein endothelial cells (HUVECs) and vascular smooth muscle cells (VSMCs) through serum starvation (SS). After the cells were subjected to SS, we found that the mRNA expression of angiotensinogen (AGT) was increased by >3-fold in HUVECs and by approximately 2.5-fold in VSMCs. In addition, the expression of angiotensin-converting enzyme (ACE) mRNA was increased in VSMCs but decreased to 50% in HUVECs during the same apoptotic process. Increases in the expression of AGT protein and angiotensin II (Ang II) were found in a serum-free medium conditioned by HUVECs (SSC). The increased Ang II was suppressed using lisinopril (an ACE inhibitor) treatment. Moreover, the activation of ERK1/2 induced by the SSC in VSMCs was also suppressed by losartan. In conclusion, we first demonstrated that the augmented AGT released from apoptotic endothelial cells acts as a vital progenitor of Ang II to accelerate vascular remodelling, and we suggest that blocking local augmented Ang II might be an effective strategy for restraining intimal hyperplasia.

A population-based study of the drug interaction between clopidogrel and angiotensin converting enzyme inhibitors

Aims

Clopidogrel and angiotensin converting enzyme (ACE) inhibitors are commonly co-prescribed drugs. Clopidogrel inhibits carboxylesterase 1 (CES1), the enzyme responsible for converting prodrug ACE inhibitors (such as ramipril and perindopril) to their active metabolites. The clinical implications of this potential drug interaction are unknown. The clinical consequences of the potential drug interaction between clopidogrel and prodrug ACE inhibitors were examined.

Methods

We conducted a nested case–control study of Ontarians aged 66 years and older treated with clopidogrel between September 1 2003 and March 31 2013 following acute myocardial infarction. Cases were subjects who died or were hospitalized for reinfarction or heart failure in the subsequent year, and each was matched with up to four controls. The primary outcome was a composite of reinfarction, heart failure or death. The primary analysis examined whether use of the prodrug ACE inhibitors ramipril or perindopril was more common among cases than use of lisinopril, an active ACE inhibitor.

Results

Among 45 918 patients treated with clopidogrel following myocardial infarction, we identified 4203 cases and 14 964 controls. After adjustment, we found no association between the composite outcome and use of perindopril (adjusted odds ratio (aOR) 0.94, 95% confidence interval (CI) 0.76, 1.16) or ramipril (aOR 0.97, 95% CI 0.80, 1.18), relative to lisinopril. Secondary analyses of each element of the composite outcome yielded similar findings.

Conclusions

Following myocardial infarction, use of clopidogrel with ACE inhibitors activated by CES1 is not associated with an increased risk of adverse cardiovascular outcomes relative to lisinopril. These findings suggest that the recently described drug interaction between clopidogrel and prodrug ACE inhibitors is of little clinical relevance.

Development of target-specific liposomes for delivering small molecule drugs after reperfused myocardial infarction

Although reperfusion is essential in restoring circulation to ischemic myocardium, it also leads to irreversible events including reperfusion injury, decreased cardiac function and ultimately scar formation. Various cell types are involved in the multi-phase repair process including inflammatory cells, vascular cells and cardiac fibroblasts. Therapies targeting these cell types in the infarct border zone can improve cardiac function but are limited by systemic side effects. The aim of this work was to develop liposomes with surface modifications to include peptides with affinity for cell types present in the post-infarct myocardium. To identify peptides specific for the infarct/border zone, we used in vivo phage display methods and an optical imaging approach: fluorescence molecular tomography (FMT). We identified peptides specific for cardiomyocytes, endothelial cells, myofibroblasts, and c-Kit + cells present in the border zone of the remodeling infarct. These peptides were then conjugated to liposomes and in vivo specificity and pharmacokinetics were determined. As a proof of concept, cardiomyocyte specific (I-1) liposomes were used to deliver a PARP-1 (poly [ADP-ribose] polymerase 1) inhibitor: AZ7379. Using a targeted liposomal approach, we were able to increase AZ7379 availability in the infarct/border zone at 24h post-injection as compared with free AZ7379. We observed ~3-fold higher efficiency of PARP-1 inhibition when all cell types were assessed using I-1 liposomes as compared with negative control peptide liposomes (NCP). When analyzed further, I-1 liposomes had 9-fold and 1.5-fold higher efficiencies in cardiomyocytes and macrophages, respectively, as compared with NCP liposomes. In conclusion, we have developed a modular drug delivery system that can be targeted to cell types of therapeutic interest in the infarct border zone.

Isolation of an Angiotensin I-Converting Enzyme Inhibitory Protein with Antihypertensive Effect in Spontaneously Hypertensive Rats from the Edible Wild Mushroom Leucopaxillus tricolor

An 86-kDa homodimeric angiotensin I-converting enzyme (ACE) inhibitory protein designated as LTP was isolated from fruit bodies of the mushroom Leucopaxillus tricolor. The isolation procedure involved ultrafiltration through a membrane with a molecular weight cutoff of 10-kDa, ion exchange chromatography on Q-Sepharose, and finally fast protein liquid chromatography-gel filtration on Superdex 75. LTP exhibited an IC₅₀ value of 1.64 mg∙mL⁻¹ for its ACE inhibitory activity. The unique N-terminal amino acid sequence of LTP was disclosed by Edman degradation to be DGPTMHRQAVADFKQ. In addition, seven internal sequences of LTP were elucidated by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Results of the Lineweaver-Burk plot suggested that LTP competitively inhibited ACE. Both LTP and the water extract of L. tricolor exhibited a clear antihypertensive effect on spontaneously hypertensive rats.

2013 Korean Society of Hypertension guidelines for the management of hypertension. Part II-treatments of hypertension

Treatment strategies are provided in accordance with the level of global cardiovascular risk, from lifestyle modification in the lower risk group to more comprehensive treatment in the higher risk group. Considering the common trend of combination drug regimen, the choice of the first drug is suggested more liberally according to the physician's discretion.

Epidemiology and management of antiretroviral-associated cardiovascular disease

Risk and manifestations of cardiovascular disease (CVD) in patients infected with human immunodeficiency virus (HIV) will continue to evolve as improved treatments and life expectancy of these patients increases. Although initiation of antiretroviral (ARV) therapy has been shown to reduce this risk, some ARV medications may induce metabolic abnormalities, further compounding the risk of CVD. In this patient population, both pharmacologic and nonpharmacologic strategies should be employed to treat and reduce further risk of CVD. This review summarizes epidemiology data of the risk factors and development of CVD in HIV and provides recommendations to manage CVD in HIV-infected patients.

Characterisation of selected active agents regarding pKa values, solubility concentrations and pH profiles by SiriusT3

The aim of this work was to determine pKa values and solubility properties of 34active agents using the SiriusT3 apparatus. The selected drug substances belong to the groups of ACE-inhibitors, β-blockers, antidiabetics and lipid lowering substances. Experimentally obtained pKa and intrinsic solubility values were compared to calculated values (program ACD/ChemSketch) and pKa values to published data as well. Solubility-pH profiles were generated to visualise the substance solubility over the gastrointestinal pH range. The relationship between the solubility characteristic of a substance, its bioavailability and categorisation according to the Biopharmaceutics Classification System (BCS) was examined as well. The results showed a good agreement between experimentally obtained, calculated and published pKa values. The measured and calculated intrinsic solubility values indicated several major deviations. All solubility-pH profiles showed the expected shape and appearance for acids, bases or zwitterionic substances. The obtained results for the pKa and solubility measurements of the examined active agents may help to predict their physicochemical behaviour in vivo, and to understand the bioavailability of the substances according to their BCS categorisation. The easy and reproducible determination of pKa and solubility values makes the SiriusT3 apparatus a useful tool in early stages of drug and formulation development.

ACEI/ARB underused in patients with type 2 diabetes in Chinese population (CCMR-3B study)

OBJECTIVE

In patients with diabetic kidney disease, it is well documented that RAS blockade is associated with an improved outcome. This observational, multicenter study examined the "real-world" use of ACEI/ARB in patients with type 2 diabetes (T2DM) in China.

METHOD

Data from the China Cardiometabolic Registries on blood pressure, blood lipid and blood glucose in Chinese T2DM patients (CCMR-3B) were used for the present study. Consecutive outpatients with T2DM for more than 6 months were recruited to this non-interventional, observational, cross-sectional study. Albuminuria was defined as urine albumin creatinine ratio (ACR) ≥ 30 mg/g.

RESULTS

A total of 25,454 outpatients with T2DM from 6 regions in China were enrolled, 47.0% were male, and 59.8% had hypertension. ACR was measured in 6,383 of these patients and 3,231 of them ≥ 30 mg/L. Among patients with hypertension, 73.0% were on antihypertensives, and 39.7% used ACEI/ARB. Of the 2,157 patients with hypertension and albuminuria, only 48.3% used ACEI/ARB. Among the non-hypertensive patients with albuminuria, ACEI/ARB usage was < 1%. Multivariate analysis revealed that comorbidities, region, hospital tier, physician specialty and patient's educational level were associated with ACEI/ARB use.

CONCLUSION

In T2DM with hypertension and albuminuria in China, more than half of them were not treated with ACEI/ARB. This real world evidence suggests that the current treatment for patients with diabetes coexisting with hypertension and albuminuria in China is sub-optimal.

Drug Interactions in Parkinson's Disease: Safety of Pharmacotherapy for Arterial Hypertension

BACKGROUND

Parkinson's disease (PD) is a progressive neurodegenerative disorder of the central nervous system, observed in patients aged older than 50 years. In this study, we review interactions between therapies used in PD and selected antihypertensive agents. Moreover, in view of the lack of evidence-based recommendations regarding the pharmacotherapy of arterial hypertension in PD patients, we propose effective and safe therapeutic algorithms for these two coexisting conditions.

METHOD

We used the "Drug interactions" database affiliated with the Ministry of Health, which allows for the identification of interactions between compared active compounds. The database is updated on a monthly basis and all data are consistent with current legislation. For information about interactions, we additionally added data from the British National Formulary, a joint publication of the British Medical Association and the Royal Pharmaceutical Society of Great Britain. In this analysis, we also used data from Micromedex^®, Cerner Multum™, Wolters Kluwer™, Lexicomp^® and Stockley's^®. We analysed the potential interactions between antihypertensive and anti-parkinsonian agents included in respective guidelines on the pharmacotherapy of these conditions.

RESULTS

Our analysis revealed the lack of clinically relevant interactions between preparations of levodopa and benserazide (used for the treatment of PD) and angiotensin-converting enzyme inhibitors, antagonists of AT₁ receptor for angiotensin II or antagonists of β-adrenoreceptors (β-adrenolytics).

CONCLUSION

To avoid major drug-to-drug interactions, patients receiving preparations of levodopa and benserazide should be prescribed angiotensin-converting enzyme inhibitors, antagonists of AT₁ receptor for angiotensin II, or antagonists of β-adrenoreceptors (β-adrenolytics) as the first-line agents of antihypertensive treatment.

Discovery of novel inhibitors for the treatment of glaucoma

INTRODUCTION

Glaucoma is a neurodegenerative disease with heterogeneous causes that result in retinal ganglionic cell (RGC) death. The discovery of ocular antihypertensives has shifted glaucoma therapy, largely, from surgery to medical intervention. Indeed, several intraocular pressure (IOP)-lowering drugs, with different mechanisms of action and RGC protective property, have been developed.

AREAS COVERED

In this review, the authors discuss the main new class of kinase inhibitors used as glaucoma treatments, which lower IOP by enhancing drainage and/or lowering production of aqueous humor. The authors include novel inhibitors under preclinical evaluation and investigation for their anti-glaucoma treatment. Additionally, the authors look at treatments that are in clinics now and which may be available in the near future.

EXPERT OPINION

Treatment of glaucoma remains challenging because the exact cause is yet to be delineated. Neuroprotection to the optic nerve head is undisputable. The novel Rho-associated kinase inhibitors have the capacity to lower IOP and provide optic nerve and RGC protection. In particular, the S-isomer of roscovitine has the capacity to lower IOP and provide neuroprotection. Combinations of selected drugs, which can provide maximal and sustained IOP-lowering effects as well as neuroprotection, are paramount to the prevention of glaucoma progression. In the near future, microRNA intervention may be considered as a potential therapeutic target.

Critical insights into the beneficial and protective actions of the kallikrein-kinin system

Hypertension is characterized by an imbalance between the renin-angiotensin system (RAS) and the kallikrein-kinin system (KKS). Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II AT-1 receptor antagonists (also known as sartans or ARBs) are potent modulators of these systems and are highly effective as first-line treatments for hypertension, diabetic nephropathies, and diseases of the brain and coronary arteries. However, these agents are mechanistically distinct and should not be considered interchangeable. In this mini-review, we provide novel insights into the often neglected roles of the KKS in the beneficial, protective, and reparative actions of ACEIs. Indeed, ACEIs are the only antihypertensive drugs that properly reduce the imbalance between the RAS and the KKS, thereby restoring optimal cardiovascular homeostasis and significantly reducing morbidity and the risk of all-cause mortality among individuals affected by hypertension and other cardiovascular diseases.

Use of different types of angiotensin converting enzyme inhibitors and mortality in systolic heart failure

BACKGROUND

Angiotensin converting enzyme-inhibitors (ACEIs) are the first-line treatment for patients with heart failure (HF) with reduced ejection fraction (EF). The benefit of ACEIs in HF is regarded as a class effect and different types of agents are used interchangeably. However, evidence on the comparable effectiveness of different ACEIs is scarce. We conducted a registry-based cohort study to assess all-cause mortality associated with the use of enalapril, perindopril, and trandolapril, as compared with ramipril, in patients with systolic HF.

METHODS

Patients with systolic HF (EF ≤40%), 2003-2012, were identified using the Danish HF Registry. New users of enalapril (n=1807), perindopril (n=1064), ramipril (n=3270), or trandolapril (n=1150), who started treatment within 60days of first-time hospital diagnosis of HF, were selected for inclusion. Subgroup analyses were conducted by sex, age, NYHA-level, EF, and ischemic heart disease. All analyses were adjusted for empirical risk scores for mortality.

RESULTS

During follow-up, 291 deaths were observed among users of enalapril (incidence rate per 100person-years [IR], 10.1), 212 among users of perindopril (IR, 10.5), 568 among users of ramipril (IR, 10.6), and 251 among users of trandolapril (IR, 12.1). No significant differences in all-cause mortality were observed with the use of enalapril (adjusted hazard ratio [aHR] 0.95, 95% CI 0.82-1.10), perindopril (aHR 1.07, 95% CI 0.92-1.26), or trandolapril (aHR 1.08, 95% CI 0.93-1.26), as compared with ramipril. No significant differences were observed in subgroup analyses.

CONCLUSIONS

These findings suggest equal effect of different types of ACEIs on mortality in systolic HF.

A crossover randomized comparative study of zofenopril and ramipril on cough reflex and airway inflammation in healthy volunteers

BACKGROUND

Persistent dry cough is a well known unwanted effect of Angiotensin-Converting Enzyme inhibitors (ACE-i). Animal studies have shown that the ACE-i zofenopril has a less tussigenic effect compared to the widely used ACE-i ramipril. The aim of this study was to compare cough sensitivity to inhaled tussigens, as well as spontaneous cough in response to the administration of zofenopril and ramipril in healthy volunteers; pharmacokinetic (PK) data of both zofenopril and ramipril, as well as their respective active forms, zofenoprilat and ramiprilat, was also collected.

METHODS

Forty healthy volunteers were enrolled in a randomized crossover study. Patients were administered zofenopril calcium salt (test drug) coated tablets, 30 mg daily dose or ramipril (reference drug) tablets, 10 mg daily dose, for 7 consecutive days in two periods separated by a 21-day wash-out period. Cough sensitivity to capsaicin and citric acid was assessed as the concentration of each tussigenic agent causing at least 2 (C2) or 5 coughs (C5); spontaneous cough was also monitored throughout the study. PK parameters of zofenopril, ramipril and their active forms, were collected for each of the two study periods. Airway inflammation, as assessed by fractional exhaled nitric oxide (FeNO) and bradykinin (BK) levels, were measured prior to and following each treatment period.

RESULTS

Ramipril, but not zofenopril, increased (p < 0.01) cough sensitivity to both tussigenic agents as assessed by C2. With citric acid, C5 values calculated after both ramipril and zofenopril administration were significantly (p < 0.05 and p < 0.01, respectively) lower than corresponding control values. With both ACE-i drugs, spontaneous cough was infrequently reported by subjects. Zofenopril/zofenoprilat PK analysis showed higher area under the curve of plasma concentration, τ values (ng/ml x h) than ramipril/ramiprilat (zofenopril vs. ramipril, 84.25 ± 34.47 vs. 47.40 ± 21.30; and zofenoprilat vs. ramiprilat, 653.67 ± 174.91 vs. 182.26 ± 61.28). Both ACE-i drugs did not affect BK plasma levels; in contrast, ramipril, but not zofenopril, significantly increased control FeNO values (from 24 ± 9.6 parts per billion [PPB] to 33 ± 16 PPB; p < 0.01).

CONCLUSIONS

Zofenopril has a more favourable profile when compared to ramipril as shown by a reduced pro-inflammatory activity and less impact on the cough reflex.

Mitigation of experimental radiation nephropathy by renin-equivalent doses of angiotensin converting enzyme inhibitors

PURPOSE

We tested five different angiotensin converting enzyme inhibitors (ACEI) as mitigators of experimental radiation nephropathy at drug doses calibrated to the plasma renin activity (PRA). This was done to determine whether all ACEI had the same efficacy as mitigators of radiation nephropathy when used at drug doses that gave equivalent suppression of the renin angiotensin system.

METHOD

10 Gy total body irradiation with bone marrow transplantation was used to cause radiation nephropathy in barrier-maintained rats. Equivalent ACEI doses were determined based on their effect to inhibit angiotensin converting enzyme (ACE) and raise the PRA in unirradiated animals.

RESULTS

PRA-equivalent doses were found for captopril, lisinopril, enalapril, ramipril and fosinopril. These doses overlap the human doses of these drugs on a body surface area basis. All ACE inhibitors, except fosinopril, mitigated radiation nephropathy; captopril was a somewhat better mitigator than lisinopril, enalapril or ramipril.

CONCLUSIONS

Most, but not all, ACEI mitigate radiation nephropathy at doses that overlap their clinically-used doses (on a body surface area basis). Fosinopril is known to be an ineffective mitigator of radiation pneumonitis, and it also does not mitigate radiation nephropathy. These pre-clinical data are critical in planning human studies of the mitigation of normal tissue radiation injury.

Intraclass differences among antihypertensive drugs

The four major classes of antihypertensive drugs—diuretics, β-blockers, calcium channel blockers, and renin-angiotensin system inhibitors (including angiotensin-converting enzyme inhibitors and angiotensin receptor blockers)—have significant qualitative and quantitative differences in the adverse effects they cause. Structural and chemical differences have been identified within these classes, especially among the calcium channel blockers and, to a lesser extent, among the thiazide/thiazide-like diuretics. However, it has been more difficult to demonstrate that these differences translate into differential effects with respect to either the surrogate endpoint of blood pressure reduction or, more importantly, hypertension-related cardiovascular complications. Based on a hierarchy-of-evidence approach, differences are apparent between hydrochlorothiazide and chlorthalidone based on evidence of moderate quality. Low-quality evidence suggests atenolol is less effective than other β-blockers. However, no significant intraclass differences have been established among the other classes of antihypertensive drugs.

Pharmacogenomics in heart failure: where are we now and how can we reach clinical application?

Heart failure is becoming increasingly prevalent in the United States and is a significant cause of morbidity and mortality. Several therapies are currently available to treat this chronic illness; however, clinical response to these treatment options exhibit significant interpatient variation. It is now clearly understood that genetics is a key contributor to diversity in therapeutic response, and evidence that genetic polymorphisms alter the pharmacokinetics, pharmacodynamics, and clinical response of heart failure drugs continues to accumulate. This suggests that pharmacogenomics has the potential to help clinicians improve the management of heart failure by choosing the safest and most effective medications and doses. Unfortunately, despite much supportive data, pharmacogenetic optimization of heart failure treatment regimens is not yet a reality. In order to attenuate the rising burden of heart failure, particularly in the context of the recent paucity of new effective interventions, there is an urgent need to extend pharmacogenetic knowledge and leverage these associations in order to enhance the effectiveness of existing heart failure therapies. This review focuses on the current state of pharmacogenomics in heart failure and provides a glimpse of the aforementioned future needs.

Contaminated heparin and outcomes after cardiac surgery: a retrospective propensity-matched cohort study

Background

During 2007 and 2008 it is likely that millions of patients in the US received heparin contaminated (CH) with oversulfated chondroitin sulfate, which was associated with anaphylactoid reactions. We tested the hypothesis that CH was associated with serious morbidity, mortality, intensive care unit (ICU) stay and heparin-induced thrombocytopenia following adult cardiac surgery.

Methods and Findings

We conducted a single center, retrospective, propensity-matched cohort study during the period of CH and the equivalent time frame in the three preceding or the two following years. Perioperative data were obtained from the institutional record of the Society of Thoracic Surgeons National Database, for which the data collection is prospective, standardized and performed by independent investigators. After matching, logistic regression was performed to evaluate the independent effect of CH on the composite adverse outcome (myocardial infarction, stroke, pneumonia, dialysis, cardiac arrest) and on mortality. Cox regression was used to determine the association between CH and ICU length of stay. The 1∶5 matched groups included 220 patients potentially exposed to CH and 918 controls. There were more adverse outcomes in the exposed cohort (20.9% versus 12.0%; difference = 8.9%; 95% CI 3.6% to 15.1%, P<0.001) with an odds ratio for CH of 2.0 (95% CI, 1.4 to 3.0, P<0.001). In the exposed group there was a non-significant increase in mortality (5.9% versus 3.5%, difference = 2.4%; 95% CI, −0.4 to 3.5%, P = 0.1), the median ICU stay was longer by 14.1 hours (interquartile range −26.6 to 79.8, S = 3299, P = 0.0004) with an estimated hazard ratio for CH of 1.2 (95% CI, 1.0 to 1.4, P = 0.04). There was no difference in nadir platelet counts between cohorts.

Conclusions

The results from this single center study suggest the possibility that contaminated heparin might have contributed to serious morbidity following cardiac surgery.

Exploring the influence of the protein environment on metal-binding pharmacophores

The binding of a series of metal-binding pharmacophores (MBPs) related to the ligand 1-hydroxypyridine-2-(1H)-thione (1,2-HOPTO) in the active site of human carbonic anhydrase II (hCAII) has been investigated. The presence and/or position of a single methyl substituent drastically alters inhibitor potency and can result in coordination modes not observed in small-molecule model complexes. It is shown that this unexpected binding mode is the result of a steric clash between the methyl group and a highly ordered water network in the active site that is further stabilized by the formation of a hydrogen bond and favorable hydrophobic contacts. The affinity of MBPs is dependent on a large number of factors including donor atom identity, orientation, electrostatics, and van der Waals interactions. These results suggest that metal coordination by metalloenzyme inhibitors is a malleable interaction and that it is thus more appropriate to consider the metal-binding motif of these inhibitors as a pharmacophore rather than a "chelator". The rational design of inhibitors targeting metalloenzymes will benefit greatly from a deeper understanding of the interplay between the variety of forces governing the binding of MBPs to active site metal ions.

Transdermal delivery of angiotensin II receptor blockers (ARBs), angiotensin-converting enzyme inhibitors (ACEIs) and others for management of hypertension

CONTEXT

Angiotensin II receptor blockers (ARBs), angiotensin-converting enzyme inhibitors (ACEIs) are some of the most commonly prescribed medications for hypertension.

OBJECTIVE

Most of all conventional dosage forms of ARBs and ACEIs undergo extensive first-pass metabolism, which significantly reduces bioavailability. Majority of ARBs and ACEIs are inherently short acting due to a rapid elimination half-life. In addition, oral dosage forms of ARBs and ACEIs have many high incidences of adverse effects due to variable absorption profiles, higher frequency of administration and poor patient compliance.

METHODS

Many attempts have been made globally at the laboratory level to investigate the skin permeation and to develop transdermal therapeutic systems of various ARBs, ACEIs and other anti-hypertensives, to circumvent the drawbacks associated with their conventional dosage form.

RESULTS

This manuscript presents an outline of the transdermal research specifically in the area of ARBs, ACEIs and other anti-hypertensives reported in various pharmaceutical journals.

CONCLUSION

The transdermal delivery has gained a significant importance for systemic treatment as it is able to avoid first-pass metabolism and major fluctuations of plasma levels typical of repeated oral administration. As we can experience from this review article that transdermal delivery of different ARBs and ACEIs improves bioavailability as well as patient compliance by many folds. In fact, the rationale development of some newer ARBs, ACEIs and other anti-hypertensives transdermal systems will provide new ways of treatment, circumventing current limitations for conventional dosage forms.

How to design a potent, specific, and stable angiotensin-converting enzyme inhibitor

Angiotensin-converting enzyme inhibitors (ACE-Is) are a valuable class of antihypertensive drugs used in the treatment of cardiovascular system-related diseases. Hence, constant research into, and the development of, such compounds remain within the priorities of modern medical sciences. In this respect, a thorough understanding of their chemistry and biology is an important aspect of drug design; therefore, we present here available data on the pharmaceutical properties of ACE-Is. We also review the structural and biochemical features of the molecular target of ACE-Is and demonstrate several known enzyme-inhibitor complexes. Finally, we attempt to create a mathematical model describing the relation between the potency and/or stability of ACE-Is and their structural characteristics using quantitative structure-activity relation (QSAR), and quantitative structure-property relation (QSPR) techniques.

Pharmacokinetics and pharmacodynamics of enalapril and its active metabolite, enalaprilat, at four different doses in healthy horses

Pharmacokinetic and pharmacodynamic of IV enalapril at 0.50 mg/kg, PO placebo and PO enalapril at three different doses (0.50, 1.00 and 2.00 mg/kg) were analyzed in 7 healthy horses. Serum concentrations of enalapril and enalaprilat were determined for pharmacokinetic analysis. Angiotensin-converting enzyme (ACE) activity, serum ureic nitrogen (SUN), creatinine and electrolytes were measured, and blood pressure was monitored for pharmacodynamic analysis. The elimination half-lives of enalapril and enalaprilat were 0.67 and 2.76 h respectively after IV enalapril. Enalapril concentrations after PO administrations were below the limit of quantification (10 ng/ml) in all horses and enalaprilat concentrations were below the limit of quantification in 4 of the 7 horses. Maximum mean ACE inhibitions from baseline were 88.38, 3.24, 21.69, 26.11 and 30.19% for IV enalapril at 0.50 mg/kg, placebo and PO enalapril at 0.50, 1.00 and 2.00 mg/kg, respectively. Blood pressures, SUN, creatinine and electrolytes remained unchanged during the experiments.

Novel Therapies of Diabetic Nephropathy

Diabetic nephropathy is currently the most common cause of end stage renal disease not only in the Western hemisphere but also in the developing nations. While the available therapeutic options remain not very effective, there is a strong ongoing effort to understand the pathogenesis better and develop more useful biomarkers. As the pathogenic mediators and signaling pathways get better defined, the scope of novel pharmaceutical agents to address such mediating factors as therapeutic targets is advancing. This review provides, in addition to a brief synopsis of currently used strategies, a comprehensive review of potential therapies that have been evolving in the past decade with a specific focus on the promising agents.

Crystal structures of highly specific phosphinic tripeptide enantiomers in complex with the angiotensin-I converting enzyme

Human somatic angiotensin-I converting enzyme (ACE) is a zinc-dependent dipeptidyl carboxypeptidase and a central component of the renin angiotensin aldosterone system (RAAS). Its involvement in the modulation of physiological actions of peptide hormones has positioned ACE as an important therapeutic target for the treatment of hypertension and cardiovascular disorders. Here, we report the crystal structures of the two catalytic domains of human ACE (N- and C-) in complex with FI, the S enantiomer of the phosphinic ACE/ECE-1 (endothelin converting enzyme) dual inhibitor FII, to a resolution of 1.91 and 1.85 Å, respectively. In addition, we have determined the structure of AnCE (an ACE homologue from Drosophila melanogaster) in complex with both isomers. The inhibitor FI (S configuration) can adapt to the active site of ACE catalytic domains and shows key differences in its binding mechanism mostly through the reorientation of the isoxazole phenyl side group at the P₁' position compared with FII (R configuration). Differences in binding are also observed between FI and FII in complex with AnCE. Thus, the new structures of the ACE-inhibitor complexes presented here provide useful information for further exploration of ACE inhibitor pharmacophores involving phosphinic peptides and illustrate the role of chirality in enhancing drug specificity.

Diabetic cardiomyopathy: mechanisms and new treatment strategies targeting antioxidant signaling pathways

Cardiovascular disease is the primary cause of morbidity and mortality among the diabetic population. Both experimental and clinical evidence suggest that diabetic subjects are predisposed to a distinct cardiomyopathy, independent of concomitant macro- and microvascular disorders. 'Diabetic cardiomyopathy' is characterized by early impairments in diastolic function, accompanied by the development of cardiomyocyte hypertrophy, myocardial fibrosis and cardiomyocyte apoptosis. The pathophysiology underlying diabetes-induced cardiac damage is complex and multifactorial, with elevated oxidative stress as a key contributor. We now review the current evidence of molecular disturbances present in the diabetic heart, and their role in the development of diabetes-induced impairments in myocardial function and structure. Our focus incorporates both the contribution of increased reactive oxygen species production and reduced antioxidant defenses to diabetic cardiomyopathy, together with modulation of protein signaling pathways and the emerging role of protein O-GlcNAcylation and miRNA dysregulation in the progression of diabetic heart disease. Lastly, we discuss both conventional and novel therapeutic approaches for the treatment of left ventricular dysfunction in diabetic patients, from inhibition of the renin-angiotensin-aldosterone-system, through recent evidence favoring supplementation of endogenous antioxidants for the treatment of diabetic cardiomyopathy. Novel therapeutic strategies, such as gene therapy targeting the phosphoinositide 3-kinase PI3K(p110α) signaling pathway, and miRNA dysregulation, are also reviewed. Targeting redox stress and protective protein signaling pathways may represent a future strategy for combating the ever-increasing incidence of heart failure in the diabetic population.

Secoisolariciresinol Diglucoside (SDG) Isolated from Flaxseed, an Alternative to ACE Inhibitors in the Treatment of Hypertension

Secoisolariciresionol diglucoside (SDG) is a plant lignan isolated from flaxseed and is phytoestrogen. SDG is a potent and long-acting hypotensive agent. Plant phytoestrogens have inhibitory effects on angiotensin-converting enzyme (ACE). The hypotensive effects of SDG, a phytoestrogen, may be mediated through inhibition of ACE. The objective of this study was to investigate if SDG-induced hypotension is mediated through inhibition of ACE. The Sprague Dawley male rats were anesthetized and trachea was cannulated. The right jugular vein was cannulated to administer the drug and the carotid artery was cannulated to record arterial pressures using PIOEZ-1 miniature model transducer (Becton, Dickinson and Company, Franklin Lakes, NJ) and Beckman dynograph (Beckman Instruments, Inc., Schiller Park, IL). The effects of angiotensin I (0.2 µg/kg, intravenously [IV]) in the absence and presence of SDG (10 mg/kg, IV), and SDG alone on systolic, diastolic, and mean arterial pressures were measured before and after 15, 30, and 60 minutes of drug administration. SDG decreased the systolic, diastolic, and mean arterial pressure by 37, 47, and 43%, respectively, at 15 minutes and 18.8, 21.2, and 20.3%, respectively, at 60 minutes. Angiotensin I increased the arterial pressure. SDG decreased angiotensin I-induced rise in the systolic, diastolic, and mean arterial pressures by 60, 58, and 51%, respectively, at 15 minutes and 48, 46, and 30%, respectively, at 60 minutes. The data suggest that SDG reduced the angiotensin I-induced rise in the arterial pressures and hence SDG is a potent ACE inhibitor.

Angiotensin-converting enzyme inhibition in cardiovascular disease: evidence with perindopril

Perindopril is a long-acting, once-daily lipophilic angiotensin-converting enzyme inhibitor with high tissue angiotensin-converting enzyme affinity, lowering angiotensin II and potentiating bradykinin. Its efficacy, safety and tolerability are well established in the treatment of hypertension and heart failure. Moreover, large morbidity-mortality trials, such as the EUropean trial on Reduction Of cardiac events with Perindopril in stable coronary Artery disease (EUROPA) and Perindopril pROtection aGainst REcurrent Stroke Study (PROGRESS), have shown that antihypertensive treatment with perindopril reduces and prevents cardiovascular disease in a large range of patients with vascular diseases, whether hypertensive or not. Thus, the outcome of these and other trials support the concept of cardiovascular protective properties of angiotensin-converting enzyme inhibition with perindopril in addition to the obvious blood-pressure-lowering effect. Considering its properties and the gathered clinical evidence on efficacy and tolerability, perindopril fulfils the criteria of the latest guidelines for hypertension and cardiovascular disease management and should therefore be considered as a first-line antihypertensive agent, forming a consistent part of the comprehensive strategy against hypertension and related cardiovascular complications.

Atrial fibrillation

Atrial fibrillation is the most common arrhythmia affecting patients today. Disease prevalence is increasing at an alarming rate worldwide, and is associated with often catastrophic and costly consequences, including heart failure, syncope, dementia, and stroke. Therapies including anticoagulants, anti-arrhythmic medications, devices, and non-pharmacologic procedures in the last 30 years have improved patients' functionality with the disease. Nonetheless, it remains imperative that further research into AF epidemiology, genetics, detection, and treatments continues to push forward rapidly as the worldwide population ages dramatically over the next 20 years.

N- versus C-domain selectivity of catalytic inactivation of human angiotensin converting enzyme by lisinopril-coupled transition metal chelates

The N- and C-terminal domains of human somatic angiotensin I converting enzyme (sACE-1) demonstrate distinct physiological functions, with resulting interest in the development of domain-selective inhibitors for specific therapeutic applications. Herein, the activity of lisinopril-coupled transition metal chelates was tested for both reversible binding and irreversible catalytic inactivation of each domain of sACE-1. C/N domain binding selectivity ratios ranged from 1 to 350, while rates of irreversible catalytic inactivation of the N- and C-domains were found to be significantly greater for the N-domain, suggesting a more optimal orientation of M-chelate-lisinopril complexes within the active site of the N-domain of sACE-1. Finally, the combined effect of binding selectivity and inactivation selectivity was assessed for each catalyst (double-filter selectivity factors), and several catalysts were found to cause domain-selective catalytic inactivation. The results of this study demonstrate the ability to optimize the target selectivity of catalytic metallopeptides through both binding and catalytic factors (double-filter effect).

Surface plasmon resonance analysis of the binding mechanism of pharmacological and peptidic inhibitors to human somatic angiotensin I-converting enzyme

Somatic angiotensin I-converting enzyme (ACE) possesses two catalytic domains and plays a major role in the regulation of blood pressure, thus representing a therapeutic target for the treatment of hypertension. We present a comprehensive surface plasmon resonance (SPR) study of the interaction of human somatic ACE with the pharmacological inhibitors captopril and lisinopril, the bradykinin potentiating peptide BPP-11b, and the food peptidic inhibitors from bovine αs2-casein, F(174)ALPQYLK(181) and F(174)ALPQY(179). SPR binding curves recorded with the high potency inhibitors captopril, lisinopril, and BPP-11b were evaluated both by regression analysis and by kinetic distribution analysis. The results indicated that captopril and lisinopril bound ACE with two K(D)'s differing by a factor 10-20 and >30, respectively (lowest K(D) = 0.1-0.3 nM for both inhibitors). This shows, for the first time in a direct binding assay with the two-domain enzyme, the existence of two binding modes of the pharmacological inhibitors, presumably with the two ACE domains. The BPP-11b-ACE binding curves were complex but showed a predominant interaction with K(D) in the nanomolar range. The caseinopeptides, known to inhibit ACE with an IC₅₀ of 4.3 μM, bound to ACE with K(D) = 3-4 μM. Mapping of the F(174)ALPQY(179) binding site on ACE by sequential binding studies using captopril or BPP-11b indicated that it bound to (or near) the two active sites of ACE, in agreement with the stoichiometry of 2 determined from data fitting. Our results provide a detailed characterization of ACE-inhibitor binding modes and validate SPR for predicting the inhibitory potential of new compounds.