Evidence for a synergistic effect of calcium channel blockers with lipid-lowering therapy in retarding progression of coronary atherosclerosis in symptomatic patients with normal to moderately raised cholesterol levels. The REGRESS Study Group

Pravastatin for lowering lipids

BACKGROUND

A detailed summary and meta-analysis of the dose-related effect of pravastatin on lipids is not available.

OBJECTIVES

Primary objective To assess the pharmacology of pravastatin by characterizing the dose-related effect and variability of the effect of pravastatin on the surrogate marker: low-density lipoprotein (LDL cholesterol). The effect of pravastatin on morbidity and mortality is not the objective of this systematic review. Secondary objectives • To assess the dose-related effect and variability of effect of pravastatin on the following surrogate markers: total cholesterol; high-density lipoprotein (HDL cholesterol); and triglycerides. • To assess the effect of pravastatin on withdrawals due to adverse effects.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials (RCTs) up to September 2021: CENTRAL (2021, Issue 8), Ovid MEDLINE, Ovid Embase, Bireme LILACS, the WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions.

SELECTION CRITERIA

Randomized placebo-controlled trials evaluating the dose response of different fixed doses of pravastatin on blood lipids over a duration of three to 12 weeks in participants of any age with and without evidence of cardiovascular disease.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility criteria for studies to be included, and extracted data. We entered lipid data from placebo-controlled trials into Review Manager 5 as continuous data and withdrawal due to adverse effects (WDAEs) data as dichotomous data. We searched for WDAEs information from all trials. We assessed all trials using Cochrane's risk of bias tool under the categories of sequence generation, allocation concealment, blinding, incomplete outcome data, selective reporting, and other potential biases.

MAIN RESULTS

Sixty-four RCTs evaluated the dose-related efficacy of pravastatin in 9771 participants. The participants were of any age, with and without evidence of cardiovascular disease, and pravastatin effects were studied within a treatment period of three to 12 weeks. Log dose-response data over the doses of 5 mg to 160 mg revealed strong linear dose-related effects on blood total cholesterol and LDL cholesterol, and a weak linear dose-related effect on blood triglycerides. There was no dose-related effect of pravastatin on blood HDL cholesterol. Pravastatin 10 mg/day to 80 mg/day reduced LDL cholesterol by 21.7% to 31.9%, total cholesterol by 16.1% to 23.3%,and triglycerides by 5.8% to 20.0%. The certainty of evidence for these effects was judged to be moderate to high. For every two-fold dose increase there was a 3.4% (95% confidence interval (CI) 2.2 to 4.6) decrease in blood LDL cholesterol. This represented a dose-response slope that was less than the other studied statins: atorvastatin, rosuvastatin, fluvastatin, pitavastatin and cerivastatin. From other systematic reviews we conducted on statins for its effect to reduce LDL cholesterol, pravastatin is similar to fluvastatin, but has a decreased effect compared to atorvastatin, rosuvastatin, pitavastatin and cerivastatin. The effect of pravastatin compared to placebo on WADES has a risk ratio (RR) of 0.81 (95% CI 0.63 to 1.03). The certainty of evidence was judged to be very low.

AUTHORS' CONCLUSIONS

Pravastatin lowers blood total cholesterol, LDL cholesterol and triglyceride in a dose-dependent linear fashion. This review did not provide a good estimate of the incidence of harms associated with pravastatin because of the lack of reporting of adverse effects in 48.4% of the randomized placebo-controlled trials.

Peripheral arterial disease and hypertension

PURPOSE OF REVIEW

Hypertension (HTN) is a well known risk factor for atherosclerosis and peripheral arterial disease (PAD). PAD affects more than 250 million people globally and is associated with worse clinical outcomes. Although multiple studies have been performed to evaluate treatment of HTN in patients with PAD, blood pressure management in this high-risk cohort remains poor.

RECENT FINDINGS

There has been conflicting evidence regarding blood pressure goals in PAD with some recent studies showing adverse outcomes with low blood pressure in this patient population. Current guidelines, however, continue to recommend treatment goals in PAD patients similar to patients without PAD. To date, no single antihypertensive drug class has shown a clear benefit in PAD population over other antihypertensive drug classes.

SUMMARY

Prospective randomized trials enrolling PAD patients are required that can shed light on optimum blood pressure target and also distinguish between different antihypertensive drugs in terms of reducing adverse outcomes.

Meta-Analysis Evaluating Calcium Channel Blockers and the Risk of Peripheral Arterial Disease in Patients With Hypertension

Clinical studies have shown that calcium channel blockers (CCB) can mitigate the progression of atherosclerosis. Their role in the primary prevention of peripheral artery disease (PAD) is unclear. We conducted a meta-analysis of randomized control trials (RCT) to compare the impact of CCB on the incidence of PAD in patients with hypertension. A comprehensive review of the literature was performed in PubMed and Cochrane registry. Studies were included if they were RCT and had outcome data on PAD with a follow-up duration of at least 6 months. CCB formed the intervention group, whereas the control group was constituted by either placebo or active treatment with any of the other antihypertensive medications. A random-effects meta-analysis was performed, and we report odds ratio as a measure of treatment effect. Our search identified 934 trials, of which 7 RCTs with 71,971 patients fulfilled the inclusion criteria. The mean duration of follow-up was 3.8 years. In patients receiving CCB, PAD events occurred in 547 out of 27,502 patients (2%) compared with 1,263 out of 42,659 patients in the control group (3%). Based on the random-effect model, the odds for development of PAD in hypertensive patients treated with CCB compared with the control group was 0.70 (95% confidence interval of 0.58 to 0.86, p = 0.0005). In conclusion, this meta-analysis of RCTs of hypertensive patients, we found that treatment with CCB was strongly associated with a decrease in the PAD compared with other antihypertensive agents or placebo.

Vascular toxicities with VEGF inhibitor therapies-focus on hypertension and arterial thrombotic events

The vascular endothelial growth factor (VEGF) signaling pathway (VSP) fulfills a cardinal role in endothelial cells and its inhibition has profound cardiovascular impact. This is true not only for the normal vasculature but also for the tumor vasculature when VSP inhibitors are used as anti-angiogenic therapies. Generalized endothelial dysfunction predisposes to vasoconstriction, atherosclerosis, platelet activation, and thrombosis (arterial more than venous). All of these have been reported with VSP inhibitors and collectively give rise to vascular toxicities, the most concerning of which are arterial thromboembolic events (ATE). VSP inhibitors include antibodies, acting extracelluarly on VEGF, such as bevacizumab and tyrosine kinases inhibitors, acting intracellularly on the kinase domain of VEGF receptors, such as sunintib and sorafenib. The addition of bevacizumab and VSP tyrosine kinase inhibitor therapy to the cancer treatment regimen is associated with a 1.5-2.5-fold and 2.3-4.6-fold increase risk of ATEs, respectively. Risk factors for ATEs while on VSP inhibitor therapy include age older than 65 years, previous thromboembolic events, history of atherosclerotic disease, and duration of VSP inhibitor therapy. In clinical practice, hypertension remains the most commonly noted vascular manifestation of VSP inhibition. Optimal blood pressure goals and preferred therapeutic strategies toward reaching these goals are not defined at present. This review summarizes current data on this topic and proposes a more intensive management approach to patients undergoing VSP inhibitor therapy including Systolic Blood PRessure Intervention Trial (SPRINT) blood pressure goals, pleiotropic vasoprotective agents such as angiotensin converting enzyme inhibitors, amlodipine, and carvedilol, high-dose statin therapy, and aspirin.

Discovery and Development of Calcium Channel Blockers

In the mid 1960s, experimental work on molecules under screening as coronary dilators allowed the discovery of the mechanism of calcium entry blockade by drugs later named calcium channel blockers. This paper summarizes scientific research on these small molecules interacting directly with L-type voltage-operated calcium channels. It also reports on experimental approaches translated into understanding of their therapeutic actions. The importance of calcium in muscle contraction was discovered by Sidney Ringer who reported this fact in 1883. Interest in the intracellular role of calcium arose 60 years later out of Kamada (Japan) and Heibrunn (USA) experiments in the early 1940s. Studies on pharmacology of calcium function were initiated in the mid 1960s and their therapeutic applications globally occurred in the the 1980s. The first part of this report deals with basic pharmacology in the cardiovascular system particularly in isolated arteries. In the section entitled from calcium antagonists to calcium channel blockers, it is recalled that drugs of a series of diphenylpiperazines screened in vivo on coronary bed precontracted by angiotensin were initially named calcium antagonists on the basis of their effect in depolarized arteries contracted by calcium. Studies on arteries contracted by catecholamines showed that the vasorelaxation resulted from blockade of calcium entry. Radiochemical and electrophysiological studies performed with dihydropyridines allowed their cellular targets to be identified with L-type voltage-operated calcium channels. The modulated receptor theory helped the understanding of their variation in affinity dependent on arterial cell membrane potential and promoted the terminology calcium channel blocker (CCB) of which the various chemical families are introduced in the paper. In the section entitled tissue selectivity of CCBs, it is shown that characteristics of the drug, properties of the tissue, and of the stimuli are important factors of their action. The high sensitivity of hypertensive animals is explained by the partial depolarization of their arteries. It is noted that they are arteriolar dilators and that they cannot be simply considered as vasodilators. The second part of this report provides key information about clinical usefulness of CCBs. A section is devoted to the controversy on their safety closed by the Allhat trial (2002). Sections are dedicated to their effect in cardiac ischemia, in cardiac arrhythmias, in atherosclerosis, in hypertension, and its complications. CCBs appear as the most commonly used for the treatment of cardiovascular diseases. As far as hypertension is concerned, globally the prevalence in adults aged 25 years and over was around 40% in 2008. Usefulness of CCBs is discussed on the basis of large clinical trials. At therapeutic dosage, they reduce the elevated blood pressure of hypertensive patients but don't change blood pressure of normotensive subjects, as was observed in animals. Those active on both L- and T-type channels are efficient in nephropathy. Alteration of cognitive function is a complication of hypertension recognized nowadays as eventually leading to dementia. This question is discussed together with the efficacy of CCBs in cognitive pathology. In the section entitled beyond the cardiovascular system, CCBs actions in migraine, neuropathic pain, and subarachnoid hemorrhage are reported. The final conclusions refer to long-term effects discovered in experimental animals that have not yet been clearly reported as being important in human pharmacotherapy.

Simultaneous determination of rosuvastatin and amlodipine in human plasma using tandem mass spectrometry: Application to disposition kinetics

The liquid chromatography–tandem mass spectrometric assay method for the simultaneous determination of rosuvastatin and amlodipine in human plasma using deuterated analogs as internal standards has been developed and validated. The analytes were extracted from 100 μL aliquots of human plasma via liquid–liquid extraction using a mixture of ethyl acetate and n-hexane (80:20, v/v) as an extraction solvent. The optimized mobile phase was composed of 0.1% formic acid in 5 mM ammonium acetate, methanol, and acetonitrile (20:20:60, v/v/v) and delivered at a flow rate of 0.75 mL/min. The calibration curve obtained was linear (R² ⩾ 0.999) over the concentration range of 0.52–51.77 ng/mL for rosuvastatin and 0.10–10.07 ng/mL for amlodipine. A sample turnover rate of less than 2.5 min makes it an attractive procedure in high-throughput bioanalysis of rosuvastatin and amlodipine. The present method was found to be applicable to clinical studies and the results were authenticated by incurred sample reanalysis.

Endothelial dysfunction in diabetes: pathogenesis, significance, and treatment

Type 2 diabetes (T2D) markedly increases the risk of cardiovascular disease. Endothelial dysfunction (ED), an early indicator of diabetic vascular disease, is common in T2D and independently predicts cardiovascular risk. Although the precise pathogenic mechanisms for ED in T2D remain unclear, at inception they probably involve uncoupling of both endothelial nitric oxide synthase activity and mitochondrial oxidative phosphorylation, as well as the activation of vascular nicotinamide adenine dinucleotide phosphate oxidase. The major contributing factors include dyslipoproteinemia, oxidative stress, and inflammation. Therapeutic interventions are designed to target these pathophysiological factors that underlie ED. Therapeutic interventions, including lifestyle changes, antiglycemic agents and lipid-regulating therapies, aim to correct hyperglycemia and atherogenic dyslipidemia and to improve ED. However, high residual cardiovascular risk is seen in both research and clinical practice settings. Well-designed studies of endothelial function in appropriately selected volunteers afford a good opportunity to test new therapeutic interventions, paving the way for clinical trials and utilization in the care of the diabetic patient. However, based on the results from a recent clinical trial, niacin should not be added to a statin in individuals with low high-density lipoprotein cholesterol and very well controlled low-density lipoprotein cholesterol.

Simultaneous determination of atorvastatin, amlodipine, ramipril and benazepril in human plasma by LC-MS/MS and its application to a human pharmacokinetic study

A rapid, simple, sensitive and specific LC-MS/MS method has been developed and validated for the simultaneous estimation of atorvastatin (ATO), amlodipine (AML), ramipril (RAM) and benazepril (BEN) using nevirapine as an internal standard (IS). The API-4000 LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. Analytes and IS were extracted from plasma by simple liquid-liquid extraction technique using ethyl acetate. The reconstituted samples were chromatographed on C(18) column by pumping 0.1% formic acid-acetonitrile (15:85, v/v) at a flow rate of 1 mL/min. A detailed validation of the method was performed as per the FDA guidelines and the standard curves were found to be linear in the range of 0.26-210 ng/mL for ATO; 0.05-20.5 ng/mL for AML; 0.25-208 ng/mL for RAM and 0.74-607 ng/mL for BEN with mean correlation coefficient of ≥0.99 for each analyte. The intra-day and inter-day precision and accuracy results were well with in the acceptable limits. A run time of 2.5 min for each sample made it possible to analyze more than 400 human plasma samples per day. The developed assay method was successfully applied to a pharmacokinetic study in human male volunteers.

End organ protection by calcium-channel blockers

In recent years, much attention has been given to end organ protection by antihypertensive, anti-heart failure, and anti-ischemic medications. This review describes the available information on end organ protection by calcium-channel blockers (CCBs). In normotensive patients and patients with hypertension treated with long-acting dihydropyridines, medial thickness was thinner than in patients treated with atenolol or in untreated hypertensive patients. Long-term treatment was associated with significant reduction in left ventricular mass. Calcium-channel blockers also improved endothelial-dependent relaxation and reversed the vasoconstrictive response to nitric oxide inhibitors. In diabetic patients, CCBs were effective in preserving kidney function and microalbuminurea. The combination of angiotensin-converting enzyme (ACE) inhibitors and CCBs was more effective than ACE inhibitors alone in preserving kidney function. In animal experiments, CCBs prevented development of coronary atheroschlerosis; however, in humans only limited data are available on their antiatherogenic effect. Some studies suggest that CCBs exert antiplatelets properties and may therefore be beneficial in patients with coronary artery disease.

Development and validation of a highly sensitive and robust LC-ESI-MS/MS method for simultaneous quantitation of simvastatin acid, amlodipine and valsartan in human plasma: application to a clinical pharmacokinetic study

A high-throughput, simple, highly sensitive and specific LC-MS/MS method has been developed for simultaneous estimation of simvastatin acid (SA), amlodipine (AD) and valsartan (VS) with 500 microL of human plasma using deuterated simvastatin acid as an internal standard (IS). The API-4000 LC-MS/MS was operated under the multiple reaction-monitoring mode (MRM) using electrospray ionization. The assay procedure involved precipitation of SA, AD, VS and IS from plasma with acetonitrile. The total run time was 2.8 min and the elution of SA, AD, VS and IS occurred at 1.81, 1.12, 1.14 and 1.81 min, respectively; this was achieved with a mobile phase consisting of 0.02 M ammonium formate (pH 4.5):acetonitrile (20:80, v/v) at a flow rate of 0.50 mL/min on an X-Terra C18 column. A linear response function was established for the range of concentrations 0.5-50 ng/mL (r > 0.994) for VS and 0.2-50 ng/mL (r > 0.996) for SA and AD. The method validation parameters for all three analytes met the acceptance as per FDA guidelines. This novel method has been applied to human pharmacokinetic study.

Fixed combination of amlodipine and atorvastatin in cardiovascular risk management: patient perspectives

Hypertension and dyslipidemia are two of the most commonly co-occurring cardiovascular risk factors which together cause an increase in coronary heart disease-related events that is more than simply additive for anticipated event rates with each condition. Data have shown that even relatively small reductions in both blood pressure and cholesterol levels can lead to large reductions in the risk for cardiovascular events. However, though there are robust data on the beneficial effect of concomitant reduction in these risk factors, the reality is that this is achieved in <10% of patients. There is nonadherence with prescribed therapies with up to 50% of patients stopping their medications of their own volition for a variety of reasons. There is a reasonable evidence base to suggest that simplifying drug regimens and reducing pill burden will enhance patient adherence. The fixed-dose combination containing the antihypertensive agent amlodipine besylate and the statin atorvastatin is the first combination of its kind, which is both efficacious and safe and could potentially improve medication compliance, thereby improving the outcomes in these patients.

Treatment with amlodipine and atorvastatin has additive effect on blood and plaque inflammation in hypertensive patients with carotid atherosclerosis

Since previous studies have reported a beneficial effect of amlodipine and atorvastatin treatment in experimental atherosclerosis, we aimed to investigate the effect of the combination of both drugs on blood and plaque inflammation in patients with carotid stenosis. For that purpose, twenty six hypertensive patients undergoing carotid endarterectomy were randomized to receive either atorvastatin 20 mg/day alone (ATV, n=12) or in combination with amlodipine 20 mg/day (ATV+AML, n=14) before scheduled carotid endarterectomy. At the end of follow-up (4-6 weeks), there was a significant decrease in total and LDL-cholesterol levels, but not in blood pressure levels. In contrast, decreased MCP-1 plasma levels, NF-kappaB activation (EMSA) and MCP-1 mRNA expression (quantitative PCR) was only observed in blood from ATV+AML treated-patients. Moreover, carotid atherosclerotic plaques from ATV+AML group demonstrated a significant reduction in macrophage infiltration in relation to ATV group (immunohistochemistry). Our results suggest that combined treatment with atorvastatin and amlodipine decreases inflammatory status of atherosclerotic patients more than atorvastatin treatment alone, suggesting that co-administration of both drugs could have beneficial additive effects.

Calcium channel blockers and angiotensin-converting enzyme inhibitors may be associated with altered atherosclerotic plaque size and morphology

Correlations of atherosclerotic plaque attributes with clinical presentation have not been studied in peripheral arterial disease (PAD). The aim of the current study was to identify clinical variables associated with alterations in PAD plaque morphology. Thirty-one patients underwent intravascular ultrasonography (IVUS) at the time of arteriography for symptomatic PAD. IVUS data were analyzed with radiofrequency techniques for quantification of plaque composition, plaque volume, and total vessel volume. Associations between plaque characteristics and clinical variables were evaluated. Univariable and multivariable analyses were performed using t-test, Pearson correlations, F-tests, and analysis of variance. Calcium (Ca2+) channel blocker use was associated with a smaller total atherosclerotic plaque burden (44.2 +/- 2.7 vs 52.9 +/- 2.5%; p < .05), and decreased fibrous plaque content (18.2 +/- 1.8% vs 24.0 +/- 1.9%; p < .05). Angiotensin-converting enzyme (ACE) inhibitor use, however, was associated with a larger total atherosclerotic plaque burden (58.3 +/- 2.2% vs 42.9 +/- 2.1%; p < .01) and larger fibrous plaque content (27.2 +/- 2.0% vs 17.7 +/- 1.6%; p < .001). Multivariable analysis was performed to evaluate which factors may differentially impact the response variable measurements of plaque volume to vessel volume. Based on this model, those without the use of an antihyperlipidemic agent or ACE inhibitor had an average total atherosclerotic plaque burden of 47.7%. Those on an antihyperlipidemic agent had an average decrease of 7.0% (p < .05), whereas those on ACE inhibitors had an average increase of 16.2% from the baseline value (p < .001). The use of calcium channel blockers is associated with significantly decreased atherosclerotic plaque burden and decreased fibrous plaque content, whereas the use of ACE inhibitors was associated with an increase in plaque burden and an increased fibrous plaque content. The use of these medications in PAD may alter plaque morphology with the potential to affect clinical outcomes.

Amlodipine/atorvastatin fixed-dose combination: a review of its use in the prevention of cardiovascular disease and in the treatment of hypertension and dyslipidemia

Amlodipine/atorvastatin (Caduet) is a once-daily fixed-dose combination of the dihydropyridine calcium channel antagonist amlodipine and the HMG-CoA reductase inhibitor atorvastatin. In Europe, the combination is indicated for the prevention of cardiovascular events in hypertensive patients with three concomitant cardiovascular risk factors and, in the US, it is indicated for the management of hypertension and dyslipidemia in patients for whom treatment with both agents is appropriate. In clinical trials, the fixed-dose combination of amlodipine/atorvastatin effectively managed two important risk factors simultaneously in hypertensive patients at risk of cardiovascular disease or in those with concomitant hypertension and dyslipidemia. The combination is bioequivalent to amlodipine and atorvastatin given alone and does not modify the efficacy of either single agent. Amlodipine/atorvastatin is generally well tolerated, with a tolerability profile consistent with that of each single agent. Compared with the coadministration of each single agent, the convenience of single-pill amlodipine/atorvastatin has the potential to improve patient adherence and the management of cardiovascular risk in selected patients, thereby improving clinical outcomes.

Modulation of calcification of vascular smooth muscle cells in culture by calcium antagonists, statins, and their combination

Background Vascular calcification is an organized process in which vascular smooth muscle cells (VSMCs) are implicated primarily. The purpose of the present study was to assess the effects of calcium antagonists and statins on VSMC calcification in vitro. Methods VSMC calcification was stimulated by incubation in growth medium supplemented with 10 mmol/l β-glycerophosphate, 8 mmol/l CaCl₂, 10 mmol/l sodium pyruvate, 1 μmol/l insulin, 50 μg/ml ascorbic acid, and 100 nmol/l dexamethasone (calcification medium). Calcification, proliferation, and apoptosis of VSMCs were quantified. Results Calcium deposition was stimulated dose-dependently by β-glycerophosphate, CaCl₂, and ascorbic acid (all P < 0.01). Addition of amlodipine (0.01–1 μmol/l) to the calcification medium did not affect VSMC calcification. However, atorvastatin (2–50 μmol/l) stimulated calcium deposition dose-dependently. Combining treatments stimulated calcification to a degree similar to that observed with atorvastatin alone. Both atorvastatin and amlodipine inhibited VSMC proliferation at the highest concentration used. Only atorvastatin (50 μmol/l) induced considerable apoptosis of VSMCs. Conclusion In vitro calcification of VSMCs is not affected by amlodipine, but is stimulated by atorvastatin at concentrations ≥10 μmol/l, which could contribute to the plaque-stabilizing effect reported for statins.

Therapeutic regulation of endothelial dysfunction in type 2 diabetes mellitus

Endothelial dysfunction is universal in diabetes, being intimately involved with the development of cardiovascular disease. The pathogenesis of endothelial dysfunction in diabetes is complex. It is initially related to the effects of fatty acids and insulin resistance on 'uncoupling' of both endothelial nitric oxide synthase activity and mitochondrial function. Oxidative stress activates protein kinase C (PKC), polyol, hexosamine and nuclear factor kappa B pathways, thereby aggravating endothelial dysfunction. Improvements in endothelial function in the peripheral circulation in diabetes have been demonstrated with monotherapies, including statins, fibrates, angiotensin-converting enzyme (ACE) inhibitors, metformin and fish oils. These observations are supported by large clinical end point trials. Other studies show benefits with certain antioxidants, L-arginine, folate, PKC-inhibitors, peroxisome proliferator activated receptor (PPAR)-alpha and -gamma agonists and phosphodiesterase (PDE-5) inhibitors. However, the benefits of these agents remain to be shown in clinical end point trials. Combination treatments, for example, statins plus ACE inhibitors and statins plus fibrates, have also been demonstrated to have additive benefits on endothelial function in diabetes, but there are no clinical outcome data to date. Measurement of endothelial dysfunction in cardiovascular research can provide fresh opportunities for exploring the mechanism of benefit of new therapeutic regimens and for planning and designing large clinical trials.

Azelnidipine has anti-atherosclerotic effects independent of its blood pressure-lowering actions in monkeys and mice

Calcium channel blockers (CCBs) have been shown to improve clinical outcomes in atherosclerotic vascular disease. The mechanisms underlying the vasculoprotective effects of a third-generation calcium channel blocker, azelnidipine, are incompletely understood. We asked whether azelnidipine attenuates atherosclerosis in monkeys and mice beyond its blood pressure-lowering effects. Cynomolgus monkeys were randomized to three groups after 4 weeks of a high cholesterol diet: control group (no treatment) and 3 and 10mg/kg daily azelnidipine; these doses have no effect on systemic arterial pressure or heart rate. Atherosclerosis was induced in the aorta by balloon injury, and the diet and treatment were continued for an additional 24 weeks. Azelnidipine did not affect blood lipid profiles, but reduced the development of atherosclerosis as detected by the elimination of local oxidative stress and reduced expression of monocyte chemoattractant protein-1 and platelet-derived growth factor. Azelnidipine also reduced the proliferation and migration of vascular smooth muscle cells in vitro. In atherosclerotic ApoE-knockout (ApoE-KO) mice fed a high cholesterol diet, azelnidipine but not amlodipine reduced the development of atherosclerosis. Neither drug changed the lipid profiles or systolic blood pressure of the mice. Thus, azelnidipine at clinically relevant doses exhibited anti-atherosclerotic effects in monkeys and mice independent of its blood pressure-lowering effects, suggesting that azelnidipine might be as a "vasculoprotective calcium channel blocker".

Claims in advertisements for antihypertensive drugs in a Dutch medical journal

BACKGROUND

Advertising claims must not conflict with the official summary of product characteristics. After a drug has been approved, new clinical evidence may become available.

AIMS

To determine how the pharmaceutical industry deals with evolving clinical evidence in advertising claims for antihypertensive drugs, and whether such pharmaceutical promotion is up to standard.

METHODS

We examined all advertisements from the Dutch Journal of Medicine published between 1996 and 2004. We judged whether claims were in agreement with the information available from the summary of product characteristics or evidence from cited clinical trials. Subsequently, we reviewed whether these claims had been assessed by the Code of Practice authority.

RESULTS

We identified 50 unique advertisements with, in total, 492 appearances for 16 antihypertensive drugs. Claims of blood pressure lowering and convenient use were all judged to be sufficiently substantiated. For calcium-channel blockers, insufficiently supported safety claims had been made in three cases (41 appearances). Claims suggesting effects on long-term outcomes started in 1999 for angiotensin II receptor blockers, and were made during the whole period for several other antihypertensive drugs. In 16 cases (135 appearances), such claims were not supported by the available information. Some claims were premature, others transferred results from a specific patient group to the general population of hypertensive patients. Only two cases were reviewed by the Code of Practice authority.

CONCLUSIONS

Overall, 35% of the advertisements for antihypertensive drugs contained suggestive claims not supported by the offered evidence. The current system of self-regulation cannot ensure that pharmaceutical promotion is always accurate, balanced and evidence-based.

Vascular Protection of Dual Therapy (Atorvastatin-Amlodipine) in Hypertensive Patients

Hypertension frequently coexists with other cardiovascular risk factors, such as hypercholesterolemia, and their combination is associated with a greater rate of cardiovascular events. Recent clinical data support that treatment of hypertensive patients with a combination of antihypertensive and lipid-lowering therapies leads to a higher reduction in the incidence of cardiovascular events. In the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BPLA), an optimal prevention of cardiovascular events was reached in patients who were randomly assigned to atorvastatin and the amlodipine treatment. However, the potential underlying mechanisms of these vascular protective effects are not fully elucidated. Because experimental studies have shown that statins and calcium channel blockers have antiatherosclerotic effects, the effect of atorvastatin alone or in combination with amlodipine was analyzed in the protein secretion profile of atherosclerotic plaques that were cultured ex vivo. In this respect, the addition of atorvastatin and amlodipine to atherosclerotic plaques normalized the levels of the different released proteins to that obtained from healthy arteries. This review highlights recent clinical and experimental studies that support that a combined treatment of hypertensive patients with both statins and calcium channel blockers could promote a higher reduction in their global cardiovascular risk profile and associated mortality. As an example, the application of a proteomic approach to assess the modulation by atorvastatin alone or in combination with amlodipine on the proteins that are released by atherosclerotic plaques has allowed the identification of novel therapeutic targets by which these drugs could promote their additive/synergic effects.

Anti-Atherosclerotic Effect of Amlodipine, Alone and in Combination With Atorvastatin, in APOE*3-Leiden/hCRP Transgenic Mice

We investigated the pleiotropic effects of a calcium antagonist (amlodipine) on early atherosclerosis development in the presence and absence of an HMG-CoA-reductase inhibitor (atorvastatin) in apolipoprotein E*3-Leiden/human C-reactive protein (E3L/CRP) transgenic mice. Male E3L/CRP transgenic mice were fed a cholesterol-containing diet either with or without amlodipine and/or atorvastatin. After 31 weeks, atherosclerosis in the aortic root area was quantified. Treatment with amlodipine did not significantly lower blood pressure, but resulted in a 43% reduction (P < 0.03) of lesion area as compared with the untreated group. Treatment with atorvastatin resulted in an 80% reduction of lesion area as compared with the untreated group (P < 0.001). Combined treatment with amlodipine and atorvastatin decreased the lesion area by 93%, significantly more than either treatment alone (P < 0.008). Plasma C-reactive protein levels were mildly elevated, on average 10 +/- 6 mg/L, and did not differ between groups, neither on baseline nor during treatment. Treatment with amlodipine, independently of blood pressure lowering, reduced atherosclerosis development in E3L/CRP mice. Atorvastatin had a strong anti-atherosclerotic effect, whereas co-treatment with amlodipine enhanced this effect significantly. Plasma C-reactive protein levels were not affected by any of the three treatments.

Divergent action of calcium channel blockers on ATP-binding cassette protein expression

Calcium channel blockers (CCBs) are widely used in clinical practice, and have been reported to be effective in preventing the progression of atherosclerosis. We examined whether various types of calcium channel blockers affected the expression of ATP binding cassette transporter A1 (ABCA1), a factor contributing to anti-atherogenesis. Undifferentiated monocytic cell line, THP-1 cells were maintained in RPMI 1640 medium and treated with different kinds of calcium channel blockers. Among the calcium channel blockers tested, aranidipine and efonidipine increased ABCA1 protein expression without an increase in ABCA1 mRNA expression, whereas other calcium channel blockers (eg, nifedipine, amlodipine, and nicardipine) or T-type calcium channel blockers (eg, mibefradil and nickel chloride) failed to upregulate ABCA1 expression. H89, a protein kinase A inhibitor inhibited the aranidipine-induced ABCA1 protein expression, whereas genistein (a tyrosine kinase inhibitor), or AG490 (a JAK-2 inhibitor) had no effects. Neither of these inhibitors suppressed the efonidipine-induced ABCA1 protein expression. Intracellular cAMP levels were elevated only by aranidipine, but not by efonidipine. In conclusion, aranidipine and efonidipine have the ability to induce ABCA1 protein by distinct mechanisms; protein kinase A is involved in the aranidipine-induced ABCA1 upregulation. This non-class effect of calcium channel blockers may potentially offer beneficial action in the treatment of hypertensive subjects with atherosclerosis.

Combination Therapy with Cerivastatin and Nifedipine Improves Endothelial Dysfunction After Balloon Injury in Porcine Coronary Arteries

HMG-CoA reductase inhibitors and calcium channel blockers have antiatherogenic effects; however, their mechanisms remain to be elucidated. This study examined the effect of cerivastatin and/or nifedipine on the endothelial dysfunction in porcine balloon-injured coronary arteries. Normal male pigs were randomly divided into the following four groups: control, cerivastatin (1 mg/kg/d PO), nifedipine (4 mg/kg/d PO), and their combination (n = 10 each). We started the treatments 3 days before balloon injury in the proximal left coronary arteries and continued for 4 weeks after the procedure. Then, we examined endothelial vasodilator functions ex vivo in organ chambers and in vitro by Western blotting for eNOS expression. Endothelium-dependent relaxations to serotonin, but not those to bradykinin or the calcium ionophore A23187 or endothelium-independent relaxations to sodium nitroprusside, were significantly impaired by balloon injury. The monotherapy with cerivastatin or nifedipine partially improved, and their combination supernormalized the relaxations to serotonin without affecting those to bradykinin or A23187 or endothelium-independent relaxations to sodium nitroprusside. The expression of eNOS was significantly reduced by balloon injury and normalized by the combination therapy. These results indicate that the combination therapy improves endothelial dysfunction after balloon injury, in which the up-regulation of eNOS may be involved.

Calcium antagonists

Calcium antagonists were introduced for the treatment of hypertension in the 1980s. Their use was subsequently expanded to additional disorders, such as angina pectoris, paroxysmal supraventricular tachycardias, hypertrophic cardiomyopathy, Raynaud phenomenon, pulmonary hypertension, diffuse esophageal spasms, and migraine. Calcium antagonists as a group are heterogeneous and include 3 main classes--phenylalkylamines, benzothiazepines, and dihydropyridines--that differ in their molecular structure, sites and modes of action, and effects on various other cardiovascular functions. Calcium antagonists lower blood pressure mainly through vasodilation and reduction of peripheral resistance. They maintain blood flow to vital organs, and are safe in patients with renal impairment. Unlike diuretics and beta-blockers, calcium antagonists do not impair glucose metabolism or lipid profile and may even attenuate the development of arteriosclerotic lesions. In long-term follow-up, patients treated with calcium antagonists had development of less overt diabetes mellitus than those who were treated with diuretics and beta-blockers. Moreover, calcium antagonists are able to reduce left ventricular mass and are effective in improving anginal pain. Recent prospective randomized studies attested to the beneficial effects of calcium antagonists in hypertensive patients. In comparison with placebo, calcium antagonist-based therapy reduced major cardiovascular events and cardiovascular death significantly in elderly hypertensive patients and in diabetic patients. In several comparative studies in hypertensive patients, treatment with calcium antagonists was equally effective as treatment with diuretics, beta-blockers, or angiotensin-converting enzyme inhibitors. From these studies, it seems that a calcium antagonist-based regimen is superior to other regimens in preventing stroke, equivalent in preventing ischemic heart disease, and inferior in preventing congestive heart failure. Calcium antagonists are also safe and effective as first-line or add-on therapy in diabetic hypertensive patients. Heart rate-lowering calcium antagonists (verapamil, diltiazem) may have an edge over the dihydropyridines in post-myocardial infarction patients and in diabetic nephropathy. Thus, calcium antagonists may be safely used in the management of hypertension and angina pectoris.

Combined antihypertensive and lipid-lowering treatment

Hypertension and hypercholesterolemia are frequently associated, and their treatment is proven to reduce cardiovascular risk. Current guidelines on cardiovascular prevention strongly recommend treating both disorders. Unfortunately, the low treatment and control rates, combined with the high prevalence of both conditions, still contribute to the high burden of cardiovascular disease in Western countries. In the past 5 years, many studies evaluating the benefit of combined antihypertensive and lipid-lowering treatment on endothelial dysfunction, coronary atherosclerosis, hypertension control, and on primary and secondary prevention of cardiovascular events have been published. In this article, we discuss and critically evaluate the available evidence on the potential benefits of combined antihypertensive and lipid-lowering treatment.

Calcium Antagonists and Atherosclerosis Protection in Hypertension

Calcium antagonists are effective in hypertensive patients of all ethnic groups, irrespective of age, dietary salt intake, salt-sensitivity status or plasma renin activity profile. Some prospective studies show that the calcium antagonists, nifedipine GITS and nitrendipine, reduce cardiovascular morbidity and mortality at least to the same extent as the diuretics. Other prospective studies are in progress to evaluate the effect of calcium antagonists on cardiovascular morbidity and mortality, and the progression of atherosclerosis in hypertensive patients. Calcium antagonists, especially the highly lipophilic amlodipine, lacidipine and nisoldipine, are shown to possess antioxidant properties. These drugs reduce the oxidation of LDL and its influx into the arterial wall, and reduce atherosclerotic lesions in animals. Platelet production of malondialdehyde, a marker of oxygen free radical formation, is suppressed by amlodipine, lacidipine or nifedipine in hypertensive patients. New evidence from long-term clinical trials of calcium antagonists indicates that these drugs can reduce the rate of progression of atherosclerosis in hypertensive and coronary heart disease patients. In the Regression Growth Evaluation Statin Study (REGRESS), co-administration of calcium antagonist, amlodipine or nifedipine with pravasatin caused a significant reduction in the appearance of new angiographic lesions. In the Verapamil in Hypertension and Atherosclerosis Study (VHAS), verapamil was more effective than chlorthalidone in promoting regression of thicker carotid lesions in parallel with a reduction in the incidence of cardiovascular events. In the Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT), amlodipine slowed the progression of early coronary atherosclerosis in patients with coronary artery disease. In a subprotocol of the Intervention as a Goal in the Hypertension Treatment (INSIGHT) study, nifedipine GITS significantly decreased intima-media thickness as compared to co-amilozide (hydrochlorothiazide + amiloride). Preliminary results of the European Lacidipine Study on Atherosclerosis (ELSA) show that lacidipine reduced the intima-media thickness progression rate as compared to atenolol. Thus, selective calcium antagonists are potential antiatherosclerotic agents.

Oxidized low-density lipoprotein induces calpain-dependent cell death and ubiquitination of caspase 3 in HMEC-1 endothelial cells

Oxidized low-density lipoprotein (oxLDL) is known to induce apoptosis in endothelial cells, and this is believed to contribute to the progression of atherosclerosis. In the present study we made the novel observation that oxLDL-induced death of HMEC-1 cells is accompanied by activation of calpain. The mu-calpain inhibitor PD 151746 decreased oxLDL-induced cytotoxicity, whereas the general caspase inhibitor BAF (t-butoxycarbonyl-Asp-methoxyfluoromethylketone) had no effect. Also, oxLDL provoked calpain-dependent proteolysis of cytoskeletal alpha-fodrin in the HMEC-1 cells. Our observation of an autoproteolytic cleavage of the 80 kDa subunit of mu-calpain provided further evidence for an oxLDL-induced stimulation of calpain activity. The Bcl-2 protein Bid was also cleaved during oxLDL-elicited cell death, and this was prevented by calpain inhibitors, but not by inhibitors of cathepsin B and caspases. Treating the HMEC-1 cells with oxLDL did not result in detectable activation of procaspase 3 or cleavage of PARP [poly(ADP-ribose) polymerase], but it did cause polyubiquitination of caspase 3, indicating inactivation and possible degradation of this protease. Despite the lack of caspase 3 activation, oxLDL treatment led to the formation of nucleosomal DNA fragments characteristic of apoptosis. These novel results show that oxLDL initiates a calpain-mediated death-signalling pathway in endothelial cells.

Differential effects of amlodipine and atorvastatin treatment and their combination on atherosclerosis in ApoE*3-Leiden transgenic mice

This study was designed to investigate the potential antiatherosclerotic effects of the calcium antagonist amlodipine as compared with the HMG-CoA reductase inhibitor atorvastatin and the combination of both in ApoE*3-Leiden transgenic mice. Four groups of 15 ApoE*3-Leiden mice were put on a high-cholesterol diet. One group received 0.002% (wt/wt) amlodipine in the diet, which had no effect on plasma cholesterol levels. Another group received 0.01% (wt/wt) atorvastatin, resulting in a decrease of plasma cholesterol by 50% by a reduction in very low density lipoprotein production. The combination group received both amlodipine and atorvastatin. After 28 weeks, atherosclerosis in the aortic root was quantified. Treatment with amlodipine had no significant effect on atherosclerotic lesion area, whereas atorvastatin markedly reduced atherosclerosis by 77% compared with the control group. Atorvastatin also reduced inflammation markers. The combination of amlodipine and atorvastatin tended to reduce lesion area by 61% compared with the atorvastatin-only group; however, this effect did not reach statistical significance. Amlodipine treatment significantly reduced calcification in the lesions, whereas atorvastatin alone had no effect. The combination of amlodipine and atorvastatin resulted in a near absence of calcium deposits in the lesions. This study demonstrates that amlodipine treatment alone does not significantly reduce atherosclerotic lesion development. Atorvastatin was shown to have strong antiatherosclerotic effects, and cotreatment with amlodipine may potentiate the antiatherosclerotic effect of atorvastatin.

Raman spectroscopic investigation of atorvastatin, amlodipine, and both on atherosclerotic plaque development in APOE*3 Leiden transgenic mice

Raman spectroscopy allows quantitative, non-destructive evaluation of entire, intact atherosclerotic plaques. We quantified the anti-atherosclerotic effects of atorvastatin and amlodipine on progression of atherosclerosis using post-mortem Raman spectroscopic plaque imaging in 28 APOE*3 Leiden transgenic mice who were fed a high fat/high cholesterol diet for 28 weeks. Mice were assigned to a control group receiving the diet alone or to groups that received the diet with either 0.01% w/w atorvastatin, 0.002% w/w amlodipine, or the combination. The entire excised aortic arch was scanned with Raman microspectroscopy for quantitation of the distribution of cholesterol and calcification content. When mice had been treated with atorvastatin, cholesterol accumulation and calcification in the aortic arch was reduced by 91 and 98%, respectively, (both P<0.001). Amlodipine did not reduce the cholesterol content but reduced calcification of the aorta by 69% (P<0.05). The combination of amlodipine and atorvastatin was as effective as atorvastatin alone. This study demonstrates the strong atheroprotective potential of atorvastatin. In addition it is demonstrated that amlodipine reduces mineralization of atherosclerotic plaque. No synergistic effect of the combination of amlodipine and atorvastatin on plaque development is demonstrated. This study encourages Raman spectroscopic evaluations of anti-atherosclerotic drugs in larger animals and humans in vivo.

Antiatherosclerotic effects of calcium channel blockers

Over the past 30 years, a considerable body of experimental and clinical evidence has accumulated to support the suggestion that calcium channel blockers (CCBs) have significant antiatherosclerotic effects that are independent of their hypotensive effects. Early research using animal models of atherosclerosis and CCBs in concentrations that exceeded the normal therapeutic dose range showed definite antiatherosclerotic effects, especially in the development of new lesions. Investigations of these effects in humans have used quantitative coronary angiography and B-mode ultrasonography and have demonstrated some antiatherosclerotic effects. This article reviews the currently available evidence of antiatherosclerotic effects of CCBs in animal models and in clinical trials.

Current strategies and perspectives for correcting endothelial dysfunction in atherosclerosis

The vascular endothelium synthesizes and releases a spectrum of vasoactive substances such as nitric oxide and endothelin. In atherosclerosis, the delicate balance between endothelium-derived factors is disturbed. Endothelin acts as the natural counterpart to endothelium-derived nitric oxide, which exerts vasodilating, antithrombotic and antiproliferative effects, and inhibits leukocyte adhesion to the vascular wall. Besides its blood pressure increasing effect in man, endothelin also induces vascular and myocardial hypertrophy, which are independent risk factors for cardiovascular morbidity and mortality. The derangement of endothelial function in atherosclerosis is likely to be caused in part by genetic factors, but is also due to cardiovascular risk factors. Endothelial dysfunction in atherosclerosis is crucial for the development of the disease process in the vasculature and is therefore an important therapeutic target. However, the efficacy of pharmacotherapy aimed at an improvement in endothelial function depends on the individual risk factor profile of the patient.

Coronary benefits of calcium antagonist therapy for patients with hypertension

Calcium antagonists effective in lowering blood pressure are a heterogeneous group including three main classes: phenylalkylamines, benzothiazepines and dihydropyridines. Dihydropyridines have a dual mode of action upon the endothelium contributing to their beneficial antihypertensive effects: (1) direct relaxation by inhibition of smooth muscle L-type calcium current, and (2) indirect relaxation through release of nitric oxide from the vascular endothelium. Calcium antagonists may affect many calcium-dependent events in the formation of atherosclerosis such as the localized accumulation of collagen, elastin, and calcium together with monocyte infiltration and smooth muscle proliferation and migration. In the INSIGHT calcification study, the overall treatment effect of nifedipine demonstrated significant inhibition of coronary calcium progression over a three-year period. Calcium antagonists improve symptoms and reduce ischemia in hypertensive patients with ischemic heart disease. Although in placebo-controlled trials calcium antagonists demonstrated a significant reduction in cardiovascular morbidity and mortality, they may be less effective than other types of antihypertensive drugs in preventing ischemic heart disease.

The effect of amlodipine on endothelial function in young adults with a strong family history of premature coronary artery disease: a randomised double blind study

Endothelial dysfunction, an early event in atherogenesis, has been demonstrated in young asymptomatic subjects with a strong family history of premature coronary artery disease (CAD). In these subjects, preventive measures involving risk factor modification are not appropriate, and strategies employing novel antiatherogenic agents, such as the dihydropyridine calcium channel blocker, amlodipine, may be useful. Ninety-one subjects (mean age, 28.6 years; range, 18-40) with a strong family history of premature CAD and no other identified vascular risk factors were randomised to either 5 mg amlodipine (49 subjects) or placebo (42 subjects). Brachial artery flow mediated dilatation (FMD) (endothelium-dependent response) and response to glyceryltrinitrate (GTN) (direct smooth muscle dilator) were assessed non-invasively at baseline, and after 12 and 24 weeks using high-resolution vascular ultrasound. In those treated with amlodipine, mean FMD increased from 2.32+/-2.23% at baseline to 3.52+/-3.1% at 24 weeks (P<0.005). However, FMD also increased in the placebo group from 1.64+/-2.12 to 3.37+/-2.68% (P<0.002), and the difference between the FMD response in the amlodipine and placebo groups was not significant. Dilatation to GTN did not change in either group. Therefore, impaired endothelial function improved in family history subjects taking both amlodipine and placebo, but there is no difference between the groups.

[Therapeutic options for improvement of myocardial perfusion in coronary atherosclerosis]

The combination of morphological atherosclerotic alterations of coronary vessels and disturbance of coronary vasomotor control of epicardial and resistance vessels determines the amount of myocardial oxygen supply. The endothelium plays a crucial role for functional alterations of the coronary vessels in patients with early atherosclerosis or risk factors for coronary artery disease. A therapy which aims to ameliorate endothelium-dependent vasodilator capacity improves myocardial perfusion in patients with coronary artery disease. Thereby, even in patients with angiographically normal or minimally diseased coronary vessels who develop myocardial ischemia due to microvascular disease, symptomatic improvement might be achieved. Control of coronary vasomotor tone and proliferation processes within the vessel wall are both determined by the redox equilibrium of nitric oxide (NO) and superoxide radicals (O2-), induced by angiotensin II. Thus, vasomotor control and vessel wall proliferation is closely related to each other. Aim of a therapeutic intervention to enhance NO bioactivity is either to increase NO production in the endothelium or to decrease O2- production, which rapidly inactivates NO. NO bioactivity can be ameliorated by ACE-inhibitors, increase of shear stress on the endothelium by physical exercise, estrogens or L-arginine. For these therapies clinically an improvement of endothelial vasodilator function could be shown. In addition, improvement of endothelial vasodilator function can be achieved by a treatment which reduced oxidative stress in the vascular wall such as antioxidants and, especially, lipid lowering drugs. Endothelin-antagonists and angiotensin II receptor-blockers are promising to improve endothelial dysfunction. However, these therapies have to be validated. Most therapy strategies, which have shown to ameliorate endothelial dysfunction, are also able to improve prognosis of the patients. Whether endothelial dysfunction alone--without evidence of overt coronary atherosclerosis--is sufficient to justify a long-term therapy to improve prognosis, still has to be clarified.

Antiatherosclerotic and antiatherogenic effects of a calcium antagonist plus statin combination: amlodipine and lovastatin

Recently, the Regression Growth Evaluation Statin Study (REGRESS) demonstrated the synergistic, antiatherogenic effect of lipid-lowering therapy with pravastatin in combination with calcium antagonists. This combination retarded the progression of stenosis and reduced the number of new lesions more effectively than did statin therapy alone. In the present study, our objective was to elucidate the mechanism of this more pronounced effect of the statin-calcium antagonist combination on the atherosclerotic lesion. Smooth muscle cells cultured from the subendothelial intima of the human aorta were incubated with whole blood serum or with low-density lipoprotein (LDL) taken from patients cotreated with lovastatin and amlodipine. Serum added to the cells cultured from the atherosclerotic lesion reduced cell cholesterol. Such an antiatherosclerotic effect of cotreatment with amlodipine-lovastatin was revealed in this study and was more pronounced than the effect of treatment with either amlodipine or lovastatin alone. LDL isolated from atherogenic plasma stimulated cell cholesterol accumulation. Treatment with amlodipine alone and the amlodipine-lovastatin combination ameliorated the atherogenic effect of LDL. As compared with amlodipine alone, the combination demonstrated a considerably higher antiatherogenic effect on LDL atherogenicity. Amlodipine-lovastatin cotreatment increased sialic acid and decreased the susceptibility of LDL to oxidation more effectively than amlodipine alone. In addition, combination therapy reduced the LDL negative charge, while amlodipine alone was impotent. These findings may serve as an explanation of the more pronounced antiatherogenic effect at the lipoprotein level of amlodipine-lovastatin combined therapy compared with amlodipine therapy alone.