Atheroprotective effects of long-acting dihydropyridine-type calcium channel blockers: evidence from clinical trials and basic scientific research

The clinical implications and management of concomitant hypertension and dyslipidemia

Hypertension and dyslipidemia often coexist, increasing the risk of cardiovascular disease. Evidence suggesting that concomitant hypertension and dyslipidemia are compelling candidates for a unified approach to treating cardiovascular risk is reviewed in this article. The authors also discuss important new findings documenting the need for, and benefits of, a more integrated approach to treating this dangerous duo.

Identification of peptides from soybean protein, glycinin, possessing suppression of intracellular Ca2+ concentration in vascular smooth muscle cells

In this study, we challenged to identify vasoactive peptides in soybean 11S glycinin hydrolysate by thermolysin to regulate intracellular Ca(2+) concentration ([Ca(2+)]i) that can induce constrictive vascular tension. As a function of the inhibition of elevated [Ca(2+)]i by 10 μM angiotensin (Ang) II in vascular smooth muscle cells (VSMCs), eleven peptides were successfully identified from the hydrolysate, among which His-Gly-Lys exhibited the most potent inhibition against [Ca(2+)]i elevation in Ang II-stimulated VSMCs (inhibition at 300 μM: 46.5±8.0% vs. control). The biological capacity of His-Gly-Lys analogues as an [Ca(2+)]i inhibitor was also proven when His-Lys and His-Gly-Arg elicited a significant reduction in [Ca(2+)]i. In contrast, less reduction of [Ca(2+)]i by His-Gly-Ile and His-(3-methyl)-Gly-Lys indicated the importance of the imino proton in His, along with basic amino acids positioned at C-terminal for the effect.

Aortic valve calcification in chronic kidney disease

Several clinical studies reported an increased prevalence and accelerated progression of aortic valve calcification among patients with end-stage renal disease when compared with subjects with normal kidney function. Recently, mechanisms of calcific valve degeneration have been further elucidated and many of the pathways involved could be amplified in patients with decreased renal function. In particular, calcium-phosphate balance, MGP metabolism, OPG/RANK/RANKL triad, fetuin-A mineral complexes and FGF-23/Klotho axis have been shown to be impaired among patients with advanced chronic kidney disease and could play a role during vascular/valve calcification. The scope of the present review is to summarize the clinical data and the pathophysiological mechanisms potentially involved in the link between renal function decline and the progression of aortic valve disease.

LIPITENSION: Interplay between dyslipidemia and hypertension

The burden of cardiovascular disease (CVD) is increasing worldwide. The increase in the burden is a major concern in developing countries like India. It is well-established that hypertension and dyslipidemia are the two major contributing risk factors for CVD. Various epidemiological studies have shown the prevalence of the co-existence of hypertension and dyslipidemia, in the range of 15 to 31%. The co-existence of the two risk factors has more than an additive adverse impact on the vascular endothelium, which results in enhanced atherosclerosis, leading to CVD. This review emphasizes on the 'co-existence and interplay of dyslipidemia and hypertension'. The authors have termed the co-existence as, 'LIPITENSION'. The term LIPITENSION may help clinicians in easy identification and aggressive management of the two conditions together, ultimately preventing future cardiovascular events.

Serum bilirubin links UGT1A1*28 polymorphism and predicts long-term cardiovascular events and mortality in chronic hemodialysis patients

BACKGROUND AND OBJECTIVES

Bilirubin is a protective factor with antioxidant and anti-inflammatory properties, but its association with clinical outcomes of hemodialysis patients is unknown. Bilirubin degradation is mainly determined by the activity of hepatic bilirubin uridine diphosphate-glucuronosyltransferase (UGT1A1), which is significantly influenced by a TA-repeat polymorphism in the gene's promoter, an allele designated UGT1A1*28. The study aimed to clarify the association between serum bilirubin and UGT1A1*28 polymorphism and their respective effect on outcomes of chronic hemodialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The cohort study comprised 661 chronic hemodialysis patients who were prospectively followed for 12 years. The endpoints were cardiovascular events (CVEs) and all-cause mortality.

RESULTS

After adjustment for traditional and dialysis-related risk factors, individuals with bilirubin in the upper tertile had an adjusted hazard ratio of 0.32 for CVEs and 0.48 for all-cause mortality compared with those in the lower tertile. Individuals homozygous for UGT1A1*28 (genotype 7/7) had significantly higher bilirubin levels than those with 6/6 and 7/6 genotypes. In the same multivariable-adjusted model, individuals with 7/7 had approximately one tenth the risk for CVEs and one fourth the risk for all-cause mortality as compared with carriers of the 6 allele.

CONCLUSIONS

A graded, reverse association was noted between serum bilirubin and adverse outcomes among chronic hemodialysis patients. Moreover, the UGT1A1*28 polymorphism had strong effects on bilirubin levels and the 7/7 genotype might have an important effect on reducing CVEs and death.

Ginsenoside-Rd, a purified component from panax notoginseng saponins, prevents atherosclerosis in apoE knockout mice

Recently, it was revealed that the dysfunction of transmembrane Ca(2+) transport, results in an increase in intracellular Ca(2+)[Ca(2+)](i), which is involved in the process of atherosclerosis. We previously demonstrated that ginsenoside-Rd, a purified component from panax notoginseng, is a voltage-independent Ca(2+) channels blocker. In this study, we investigated the effects of ginsenoside-Rd on atherosclerosis and the underlying mechanisms in apolipoprotein E deficient (apoE(-/-)) mice and RAW264.7 cells. Atherosclerotic plaques were stained by Red oil O staining. Ca(2+) influx was measured by Fura-2 dyed Mn(2+) quenching. Intracellular cholesterol and uptake of lipid was assayed by enzymatic, fluorometric method and DiI-labeled Ox-LDL. Western blot was used to determine protein expression. We found that Ginsenoside-Rd (20mg/kg/day. i.p.) significantly reduced the atherosclerotic plaque areas, oxidized low-density lipoprotein (ox-LDL) uptake and thapsigargin and l-oleoyl-2-acetyl-glycerol (OAG, membrane-permeable diacylglycerol analog)-induced Ca(2+) influx in macrophages from high-fat diet apoE(-/-) mice. In vitro, 20μM ginsenoside-Rd significantly inhibited ox-LDL-induced foam cell formation and the increase of thapsigargin- and OAG-induced Ca(2+) influx. Ox-LDL induced an increase in scavenger receptor A (SR-A) expression, and ginsenoside-Rd inhibited this effect of ox-LDL significantly. The results suggest that ginsenoside-Rd prevents the development of atherosclerosis. The underlying mechanism may be related to the inhibition of Ca(2+) influx through voltage-independent Ca(2+) channels, resulting in the inhibition of SR-A activity and expression, followed by reductions of ox-LDL uptake and cholesterol accumulation in macrophages.

Serum and gene expression profile of tumor necrosis factor-alpha and interleukin-6 in hypertensive diabetic patients: effect of amlodipine administration

Pro-inflammatory cytokines are critical factors in type 2 diabetes-associated atherosclerosis. We aim to analyze in hypertensive type 2 diabetic patients the serum concentrations and the mRNA expression levels in peripheral blood mononuclear cells (PBMC) of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), as well as to evaluate the effect of amlodipine administration. Twenty-one hypertensive diabetic patients and 10 healthy non-diabetic controls were included in the study. Serum levels of cytokines were measured by chemiluminescent immunometric assay, and mRNA expression levels by RT-PCR. The mean serum concentrations of TNF-alpha and IL-6 in diabetic patients showed a 6.1-fold and 2.9-fold increase with respect to non-diabetic control subjects, respectively (p less than 0.0001). Likewise, there was a 3.3- and a 4-fold increase in the PBMC mRNA expression level of TNF-alpha and IL-6 (p less than 0.0001) in diabetic subjects. After amlodipine administration, a significant decrease (p less than 0.01) was observed in the serum TNF-alpha and IL-6 levels. In addition, pre-treatment mRNA expression of TNF-alpha and IL-6 also decreased, with a mean percent reduction of 26 percent (p less than0.01) and 25 percent (p less than 0.001), respectively. In conclusion, serum concentrations and PBMC mRNA expression levels of TNF-alpha and IL-6 are significantly elevated in hypertensive type 2 diabetic patients. Administration of amlodipine is associated with a significant reduction of the increased levels of these inflammatory parameters, both at the protein as well as at the transcriptional level. These modulatory effects of amlodipine on proinflammatory cytokine level and expression may be related to its suggested anti-atherosclerotic actions.

L-type calcium channel blockers and Parkinson disease in Denmark

OBJECTIVE

This study was undertaken to investigate L-type calcium channel blockers of the dihydropyridine class for association with Parkinson disease (PD), because some of these drugs traverse the blood-brain barrier, are potentially neuroprotective, and have previously been evaluated for impact on PD risk.

METHODS

We identified 1,931 patients with a first-time diagnosis for PD between 2001 and 2006 as reported in the Danish national hospital/outpatient database and density matched them by birth year and sex to 9,651 controls from the population register. The index date for cases and their corresponding controls was advanced to the date of first recorded prescription for anti-Parkinson drugs, if prior to first PD diagnosis in the hospital records. Prescriptions were determined from the national pharmacy database. In our primary analyses, we excluded all calcium channel blocker prescriptions 2 years before index date/PD diagnosis.

RESULTS

Employing logistic regression analysis adjusting for age, sex, diagnosis of chronic pulmonary obstructive disorder, and Charlson comorbidity score, we found that subjects prescribed dihydropyridines (excludes amlodipine) between 1995 and 2 years prior to the index date were less likely to develop PD (odds ratio, 0.73; 95% confidence interval, 0.54-0.97); this 27% risk reduction did not differ with length or intensity of use. Risk estimates were close to null for the peripherally acting drug amlodipine and for other antihypertensive medications.

INTERPRETATION

Our data suggest a potential neuroprotective role for centrally acting L-type calcium channel blockers of the dihydropyridine class in PD that should be further investigated in studies that can distinguish between types of L-type channel blockers.

Improving vascular function in hypertension: potential benefits of combination therapy with amlodipine and renin-angiotensin-aldosterone system blockers

Hypertension is characterized by endothelial dysfunction and increased risk for adverse cardiovascular outcomes. In addition to lowering blood pressure, the calcium-channel blocker amlodipine and blockers of the renin-angiotensin-aldosterone system (angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor blockers) may further reduce cardiovascular risk by improving endothelial function when used alone or in combination. In fact, the beneficial effects of the combination of amlodipine and a renin-angiotensin-aldosterone system blocker on endothelial function have been found to be greater than the effect of either drug alone, likely due to additive effects on nitric oxide activity. This review summarizes the observed effects of these agents on endothelial function and the complementary mechanisms by which they act, thus providing rationale (beyond blood pressure benefits) for their use in combination.

Association of inflammation and protein-energy wasting with endothelial dysfunction in peritoneal dialysis patients

BACKGROUND

Cardiovascular disease is the main cause of mortality in end-stage renal disease (ESRD) patients. Recent studies have indicated that non-traditional risk factors such as endothelial dysfunction (ED), chronic inflammation and protein-energy wasting (PEW) may contribute significantly to the increased cardiovascular mortality among dialysis patients. To further ascertain this association, we carried out a cross-sectional assessment of nutritional status, inflammatory markers and endothelial dysfunction in peritoneal dialysis (PD) patients.

METHODS

We measured ED functionally by flow-mediated vasodilatation (FMD) using doppler ultrasonography and biochemically by soluble intercellular adhesion molecule-1 (sICAM-1) in 105 stable PD patients and 32 age- and sex-matched healthy controls. We also simultaneously measured inflammatory markers and performed a subjective global assessment (SGA) of their nutritional status using a seven-point scoring scale. Subjects were subgrouped according to their nutritional and inflammatory status.

RESULTS

In PD patients, FMD was markedly lower (9.9 +/- 4.8% vs. 16.4 +/- 4.8%, P < 0.05), and sICAM-1 was significantly higher than those in controls. The malnourished patients had significantly lower FMD (8.4+/-4.6% vs. 10.8+/-4.7%, P <0.05) and higher sICAM-1 than the nourished patients. The inflamed group had significantly lower FMD (7.1 +/- 3.8 vs.11.1 +/- 4.6%, P < 0.05) and higher sICAM-1 than the non-inflamed group. In all PD patients, lean body mass/body weight %, albumin and SGA correlated positively with FMD (r = +0.207, r = +0.224, r = +0.285, P < 0.05). However, age, log high sensitivity C-reactive protein (hsCRP), log IL-6 and sICAM-1 were negatively correlated with FMD (r = -0.275, r = -0.361, r = -0.360, r = -0.271, P < 0.05). A multiple regression analysis showed that log hsCRP was an independent factor affecting FMD. Endothelial function, demonstrated as FMD and sICAM-1 in the nourished PD patients without inflammation, was well preserved compared to other subgroups.

CONCLUSION

Our data suggest that chronic inflammation and PEW are closely linked to ED in PD patients.

Inadequate dietary magnesium intake increases atherosclerotic plaque development in rabbits

Epidemiological studies have shown dietary magnesium (Mg) intake and serum Mg levels to be inversely correlated with the development of atherosclerosis. We hypothesized that low levels of Mg would promote atherosclerotic plaque development in rabbits. New Zealand white rabbits (4 months old, n = 22) were fed an atherogenic diet containing 0.12% (-Mg), 0.27% (control), or 0.43% (+Mg) Mg for 8 weeks. Blood samples were obtained at baseline, 2, 4, 6, and 8 weeks and were assayed for total cholesterol, high-density lipoprotein (HDL), non-HDL, triglycerides (TG), C-reactive protein, serum Mg, and erythrocyte Mg. Aortas from -Mg had significantly more plaque, with an intima thickness 42% greater than control and 36% greater than +Mg. Serum cholesterol levels rose over time, and at 8 weeks, -Mg had the highest and +Mg the lowest total and non-HDL cholesterol and TG levels, although these results did not reach significance. Over time, serum Mg levels increased, and erythrocyte Mg levels decreased. C-reactive protein significantly increased in all groups at 4 and 6 weeks but returned to baseline levels by 8 weeks. This study supports the hypothesis that inadequate intake of Mg results in an increase in atherosclerotic plaque development in rabbits.

Combining RAAS and calcium channel blockade: ACCOMPLISH in perspective

The Avoiding Cardiovascular events through COMbination therapy in Patients LIving with Systolic Hypertension (ACCOMPLISH) trial was the first trial to compare the cardiovascular outcomes of initial fixed-dose combination angiotensin-converting enzyme inhibitor (ACEI)/calcium channel blocker (CCB) and ACEI/diuretic therapy in patients with hypertension and high risk of cardiovascular events. The initial combination therapy was effective in this population, with ACEI/CCB therapy providing the greatest benefit (reduction in risk of cardiovascular events). Whether or not the findings of ACCOMPLISH can be applied to other renin-angiotensin-aldosterone system (RAAS) inhibitor/CCB combinations, such as angiotensin receptor blocker (ARB)/CCB combinations, has yet to be investigated. The present report reviews the results of ACCOMPLISH, data from trials comparing ARB and ACEI therapies, and findings from studies of ARB/CCB combination therapy that support the use and further study of combination therapy with RAAS inhibitors and CCBs.

Coadministered amlodipine and atorvastatin produces early improvements in arterial wall compliance in hypertensive patients with dyslipidemia

BACKGROUND

Combining statins with antihypertensive therapy has been demonstrated to provide an early reduction in cardiovascular events. This nested substudy of the AVALON trial assessed the effects of coadministered amlodipine and atorvastatin vs. either therapy alone or placebo on arterial compliance, to evaluate the vascular benefits of coadministered therapy.

METHODS

During an initial 8-week, double-blind phase, patients with concomitant hypertension and dyslipidemia were randomized into four treatment groups (placebo, amlodipine 5 mg, atorvastatin 10 mg, or coadministered amlodipine 5 mg and atorvastatin 10 mg). The sustained effect of combined therapy was evaluated during subsequent 8-week, single-blind, and 12-week, open-label periods. In the single-blind phase, all patients were coadministered amlodipine 5 mg and atorvastatin 10 mg, which were then titrated to optimize blood pressure and low-density lipoprotein cholesterol control during the open-label phase. Arterial compliance was assessed every 4 weeks using the HDI/Pulsewave CR-2000.

RESULTS

Overall, 668 patients (61% male, mean age 55 years) were randomized to treatment. A 19% improvement in small artery compliance (C2) was observed with coadministered amlodipine and atorvastatin from baseline to week 8, which was significantly greater than with either treatment alone or with placebo (P = 0.03 to 0.0001). After 28 weeks, C2 was increased from baseline in all groups, but the overall improvement was greatest in the group receiving coadministered drugs for the entire study period (P < 0.05).

CONCLUSIONS

Early and sustained improvement in small artery compliance was observed following coadministration of amlodipine and atorvastatin, thus demonstrating a vascular benefit with simultaneous treatment of hypertension and dyslipidemia.

Effects of calcium channel and renin-angiotensin system blockade on intravascular and neurohormonal mechanisms of hypertensive vascular disease

Several classes of antihypertensive drugs have been shown to improve vascular function through mechanisms other than reducing blood pressure (BP) alone. Certain dihydropyridine calcium channel blockers (CCBs) and inhibitors of the renin-angiotensin system (RAS) increase nitric oxide (NO) bioavailability and decrease oxidative stress, thereby improving endothelial activity and vascular function. Pulse wave analyses have shown that these agents reduce the impact of pressure wave reflections on central systolic BP (SBP), consistent with a decrease in arterial stiffness. The complementary vascular mechanisms of these drug classes suggest that combination therapy may be effective for improving clinical outcomes. In animal model studies, combination calcium channel/RAS blockade has been shown to be more effective in improving endothelial dysfunction than treatment with drugs from either class alone. Furthermore, results from recent clinical trials suggest a greater reduction in central aortic SBP, pulse pressure, and cardiovascular events with calcium channel/RAS blockade vs. beta-blocker/diuretic therapy. These studies support the potential benefit of combination calcium channel and RAS blockade in the prevention and treatment of cardiovascular disease.

Risk-based classification of hypertension and the role of combination therapy

The recognition of a continuous relationship between elevated blood pressure (BP) and cardiovascular risk has influenced national and international guidelines for the classification, prevention, and management of hypertension. The most recent report (2003) of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure uses BP thresholds to define categories of normal, prehypertension, and hypertension. A new definition proposed by the Hypertension Writing Group in 2005 offers an approach to diagnosis and management based on global or total risk. Thus, even in the absence of sustained elevations in BP, patients may have a moderate to high risk of vascular events due to the presence of additional cardiovascular risk factors, disease markers, and target organ damage. The 2007 European guidelines continue to classify hypertension based on cutoffs while also placing emphasis on multivariate formulations for cardiovascular risk assessment and goals of therapy. All 3 sets of guidelines acknowledge the necessity of using > or =2 antihypertensive agents to attain BP goals in many patients.

Prevention of neuronal damage by calcium channel blockers with antioxidative effects after transient focal ischemia in rats

BACKGROUND

Cerebral ischemia is a major leading cause of death and at the first place cause of disability all over the world. There are a lot of drugs that are in experimental stage for treatment of stroke. Among them are calcium channel blockers (CCBs) that have, in animal models, different effectiveness in healing of ischemic damage in brain. Mechanism of CCBs' action in cerebral ischemia is still unclear, but antioxidative property is supposed to be implicated. In the present study, we investigated antioxidative and neuroprotective properties of two CCBs, azelnidipine and amlodipine.

METHODS

Male Wistar Kyoto rats were subjected to 90 min of transient middle cerebral artery occlusion (MCAO) by a nylon thread. Animals were divided into 3 groups, vehicle, azelnidipine and amlodipine group. In the azelnidipine and amlodipine groups, rats were treated with azelnidipine (1 mg/kg) and amlodipine (1 mg/kg) by gastric gavage for 2 weeks before MCAO. Vehicle group was treated by solution of methyl cellulose for 2 weeks. Rats were killed 24 h after MCAO. Physiological parameters (mean arterial pressure, heart rate, body weight), infarct volume, brain edema index, cerebral blood flow (CBF), oxidative stress markers which are HEL, 4-HNE, AGE and 8-OHdG, and evidence of apoptosis by TUNEL, were investigated.

RESULTS

There were no significant differences among groups in mean arterial pressure, heart rate and body weight. Treatment with azelnidipine and amlodipine reduced infarct volume and brain edema. Azelnidipine treated group showed more marked reduction of infarct volume and cerebral edema than amlodipine group. There was no attenuation of CBF in CCBs groups. The number of HEL, 4-HNE, AGE and 8-OHdG positive cells were significantly decreased in the CCBs treated groups. These molecules were again fewer in the azelnidipine group than in the amlodipine group. In TUNEL staining, the numbers of positive cells was smaller in the CCBs treated groups, especially in the azelnidipine group.

CONCLUSIONS

Pretreatment of azelnidipine and amlodipine had a neuroprotective effect in ischemic brain. Antioxidative property is one of the important profiles of CCBs that is implicated in brain protection.

Targeting mechanisms of hypertensive vascular disease with dual calcium channel and renin-angiotensin system blockade

Patients with hypertension, particularly those with diabetes mellitus, are at heightened risk for cardiovascular and renal disease. Accumulated evidence indicates that the majority of hypertensive patients at high risk will require more than one antihypertensive agent to reach their blood pressure (BP) target. A reasonable strategy is to use agents with complementary mechanisms of action to enhance BP-lowering efficacy and prevent target organ damage. In experimental models, the combination of a calcium channel blocker (CCB) with an agent that blocks the renin-angiotensin system (RAS), an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker, improves measures of endothelial function, inflammation, ventricular remodelling and renal function to a greater degree than these classes given as monotherapy. In clinical trials, calcium channel/RAS blockade combination therapy has been shown to provide greater BP reductions and improve renal function in patients with diabetic and nondiabetic renal disease earlier and to a greater extent than monotherapy. In addition, dual calcium channel/RAS blockade increases arterial compliance, arterial distensibility and flow-mediated vasodilation. Expanding upon extensive research on the benefits of calcium channel blockade and RAS blockade for the prevention of vascular events and preclinical and clinical trial evidence suggests added effects of combination therapy by targeting the underlying mechanisms of hypertensive vascular disease.

SDF-1-induced adhesion of monocytes to vascular endothelium is modulated by azelnidipine via protein kinase C inhibition

Monocyte-endothelial interaction and its modulation by chemokines play a key role in atherogenesis and inflammation. We examined the potential effects of stromal cell-derived factor (SDF-1) and azelnidipine, a novel dihydropyridine derivative, toward monocyte-endothelial interaction. Human monocytes were prepared from peripheral blood mononuclear cells obtained from healthy volunteers and pretreated with azelnidipine (1 microM) for 48 h, after which their adhesion to interleukin-1beta (IL-1beta)-activated human umbilical vein endothelial cells (HUVECs) was analyzed using an in vitro flow apparatus with a shear stress of 1 dyn/cm(2). In some experiments, monocytes were incubated in the presence of stromal cell-derived factor (SDF-1), a chemokine, just prior to the assay. Pre-incubation of monocytes with SDF-1 enhanced their adhesion to activated HUVECs. When monocytes were pre-incubated in the presence of azelnidipine, baseline levels as well as SDF-1-induced monocyte adhesion levels were reduced. Interestingly, the surface expressions of the adhesion molecules CD11a, CD11b, and CD36, were not changed by azelnidipine treatment. Western blotting analysis revealed that activation of protein kinase C (PKC)alpha was inhibited by azelnidipine treatment, while it also reduced the SDF-1-induced increase in intracellular calcium concentration ([Ca(2+)](i)). Further, pre-incubation of monocytes with Go6976, a potent inhibitor of PKCalpha, significantly reduced monocyte adhesion to HUVECs. Our results demonstrated an inhibitory action of azelnidipine toward adhesive interactions of monocytes to HUVECs, which involves inhibition of PKCalpha and a reduction in [Ca(2+)](i). These findings imply a protective role of azelnidipine against inflammation in atherosclerosis.

Lercanidipine reduces matrix metalloproteinase-9 activity in patients with hypertension

Increased levels of metalloproteinase (MMP)-9 have been shown in hypertensive patients. Lercanidipine is a calcium channel blocker with antioxidant actions. We examined whether lercanidipine produces antioxidant effects and reduces MMP-9 activity in hypertensive patients in a placebo-controlled, crossover, single-blinded design study including 18 healthy volunteers (control group), and 14 hypertensive patients without (N = 7) or with (N = 7) diabetes mellitus. Hypertensive patients were randomized to treatment with placebo (15 days) or lercanidipine 20 mg/d (15 days). Arterial blood pressure was evaluated with ambulatory blood pressure monitoring. Plasma thiobarbituric acid reactive species (TBA-RS) levels were measured to assess oxidative stress, and plasma MMP-2 and MMP-9 were assayed by gel zymography before and after treatment with placebo or lercanidipine. Plasma concentrations of tissue inhibitor of metalloproteinases (TIMP)-1 were measured by ELISA. Lercanidipine reduced mean arterial pressure by 7% in hypertensive patients without diabetes (P < 0.05), but not in hypertensive patients with diabetes. It significantly decreased plasma TBA-RS levels in hypertensive patients without and with diabetes (95% confidence interval [CI], -26 to -46%, P = 0.048, and -22 to -33%, P = 0.036, respectively). In addition, lercanidipine decreased activated MMP-9 in hypertensive patients without and with diabetes (95% CI, -19 to -47%, P = 0.047, and -80 to -96%, P = 0.010, respectively). No effects were seen on MMP-2. No significant differences or changes in plasma TIMP-1 concentrations were found. Therefore, we demonstrate for the first time that lercanidipine consistently decreased MMP-9 activity and reduced oxidative stress in hypertensive patients, thus suggesting a mechanism probably involved in the pleotropic actions of lercanidipine.

A rationale for combination therapy in risk factor management: a mechanistic perspective

Endothelial dysfunction contributes to mechanisms of atherogenesis and its clinical manifestations, including coronary heart disease. Cardiovascular risk factors have been linked directly to a loss of endothelial function, such as endothelium-dependent nitric oxide (NO) release, resulting in abnormal vasodilation in response to various stimuli. There is evidence that multiple risk factors, including hypertension and hyperlipidemia, lead to a synergistic effect on endothelial dysfunction, likely through oxidative stress mechanisms. Damage to the endothelium leads to reduced NO bioavailability and facilitates vessel wall permeability to low-density lipoprotein. Certain agents, including the antihypertensive drug amlodipine and the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) atorvastatin, are known to influence endothelial function and NO bioavailability directly; these properties may contribute to clinical benefits. Recent experimental evidence at the cellular level indicates that these agents stimulate NO release from human endothelial cells in a highly synergistic fashion. The clinical implications of these observations are discussed in this article in the context of cardiovascular risk factor management strategies.

Inhibition of Mitogen-Mediated Proliferation of Rat Vascular Smooth Muscle Cells by Labedipinedilol-A through PKC and ERK 1/2 Pathway

Labedipinedilol-A is a novel 1, 4-dihydropyridine type calcium antagonist with alpha-receptor blocking activity. This study investigates the effects of labedipinedilol-A on mitogen-induced proliferation of rat vascular smooth muscle cells (VSMCs). Labedipinedilol-A's inhibition on cell proliferation was measured by the tetrazolium salt (XTT) test. Labedipinedilol-A dose-dependently inhibited mitogen-induced DNA synthesis, determined by the incorporation of 5-bromo-2'-deoxyuridine (BrdU). Labedipinedilol-A was also found capable of inhibiting the migration of VSMCs induced by PDGF-BB with an IC50 value of 5.6 microM. In accordance with these findings, labedipinedilol-A revealed blocking of the FBS-inducible progression through G0/G1 to S phase of the cell cycle in synchronized cells. Labedipinedilol-A appeared to cause inhibition of mitogens-induced PKC translocation, suggesting the probable involvement of protein kinase C (PKC) in this cellular response. Labedipinedilol-A reduced both intracellular Ca and the phosphorylation of extracellular signal-regulated protein kinase 1/2 in PDGF-BB-stimulated VSMCs. It also suppressed the levels of proliferative cell nuclear antigen (PCNA) in VSMCs both time- and dose-dependently. These results indicate that labedipinedilol-A may inhibit cell proliferation by attenuating activation of the ERK 1/2 pathway, which is regulated by PKC and Ca, suggesting that it may have great potential in the prevention of progressive atherosclerosis.

Novel diacylglycerol kinase inhibitor selectively suppressed an U46619-induced enhancement of mouse portal vein contraction under high glucose conditions

1. Diacylglycerol kinase (DG kinase) is a key enzyme in vascular contraction; however, alterations of the regulatory mechanisms in vascular dysfunction are poorly understood. In this study, the effect of a novel DG kinase inhibitor, stemphone, on vascular contraction was investigated. 2. The conventional DG kinase inhibitor, 6-[2-(4-[(4-fluorophenyl)phenyl-methylene]-1-piperidinyl)ethyl]-7-methyl-5H-thiazolo [3,2-alpha] pyrimidine-5-one (R59022) (0.1-30 microm), inhibited thromboxane A(2) analogue 9,11-dideoxy-11alpha,9alpha-epoxymethanoprostaglandin F(2alpha) (U46619)-induced sustained contractions in mouse aorta and porcine coronary artery in a dose-dependent manner. Treatment with stemphone did not affect contractions in these tissues. However, stemphone significantly inhibited (>0.3 microm) U46619-induced spontaneous phasic contraction in mouse portal vein. This inhibitory effect was not detected following R59022 treatment in portal vein. Therefore, stemphone demonstrated selectivity in terms of portal vein contraction. 3. Under high glucose (22.2 mm) conditions, U46619-induced contraction was enhanced in these three types of vascular tissue. Inhibitory effects of R59022 were attenuated under these conditions; however, effects of stemphone were observed. These results indicated that stemphone could inhibit portal vein contraction under high glucose conditions, for example, diabetes. These data suggested the possibility that DG kinase may be a target of hyperportal pressure. 4. Total mass of DG was enhanced under high glucose conditions. DG was derived from incorporated glucose via de novo synthesis in the absence of phospholipase C pathway mediation. This enhanced DG under high glucose conditions activated a calcium-independent protein kinase C (PKC). This PKC was associated with calcium-independent DG kinase activation. Treatment with stemphone also inhibited calcium-independent DG kinase. These signal transduction pathways were distinguishable from a DG-PKC pathway under normal glucose conditions. 5. The present investigation suggested that stemphone selectively inhibited overcontraction of portal vein induced by high glucose levels. This phenomenon was attributable to inhibition of calcium-independent DG kinase activation that occurred under high glucose conditions mediated by both DG synthesized from glucose and calcium-independent PKC activation.

The first hypertension trial comparing the effects of two fixed-dose combination therapy regimens on cardiovascular events: Avoiding Cardiovascular events through Combination therapy in Patients Living with Systolic Hypertension (ACCOMPLISH)

Current recommendations for the treatment of hypertension clarify the need to achieve lower blood pressure levels in the general population (<140/90 mm Hg) and in specific high-risk patient groups such as patients with diabetes or chronic renal disease (<130/80 mm Hg). Further, it is evident that to reach appropriate blood pressure control, most patients with high blood pressure will require two or more antihypertensive agents. There is scarce clinical trial outcome evidence to guide clinicians in the selection of optimal combinations of antihypertensive classes for high-risk hypertensive patients. A new clinical trial, Avoiding Cardiovascular Events through Combination Therapy in Patients Living with Systolic Hypertension (ACCOMPLISH), is the first large clinical trial to directly compare cardiovascular mortality and morbidity rates for two fixed-dose combination therapies. Results from ACCOMPLISH should provide much-needed guidance for selecting optimal combination therapy for high-risk hypertensive patients.

Edaravone, a Radical Scavenger, May Enhance or Produce Antiproliferative Effects of Fluvastatin, Amlodipine, Ozagrel, GF109203X, Y27632 on Cultured Basilar Artery Smooth Muscle Cells

Proliferation of vascular smooth muscle cells stimulated by reactive oxygen species (ROS) may play a pivotal role in the pathogenesis of atherosclerosis. To clarify mechanisms by which ROS promote vascular atherogenesis, effects of fluvastatin, amlodipine, ozagrel (thromboxane synthetase inhibitor), GF109203X (a protein kinase C inhibitor) and Y27632 (a ROCK inhibitor) on the proliferation of guinea-pig basilar artery smooth muscle cells (GBa-SM3) in a 5% FBS culture medium were studied over 3 d in the presence or absence of a free radical scavenger, edaravone. Viability of cells at the end of incubation was measured by the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test. Results demonstrated that fluvastatin and amlodipine by themselves possess antiproliferative effects on the GBa-SM3 cells at 10-100 microM and 0.1-1 microM, respectively. While edaravone possessed no antiproliferative effect by itself at 100 microM, it significantly (p<0.05) augmented the antiproliferative effects of fluvastatin and amlodipine. In addition, ozagrel, GF109203X and Y27632 possessed no appreciable effects on the cell growth by themselves. However, coincubation of edaravone at 100 microM with these agents elicited significant antiproliferative effects for ozagrel, GF109203X and Y27632 at 10-100 microM, 1-10 microM and 0.1-1 microM, respectively. In conclusion, edaravone may have clinically beneficial interactions with fluvastatin, amlodipine and ozagrel regarding the prevention of vascular atherosclerosis. The interactions between edaravone and the inhibitors of protein kinase C and ROCK were suggestive of possible contributions of ROS-triggered intracellular signals associated with these enzymes to vascular atherogenesis, but further studies are required for confirmation.