Quantitative Coronary Angiogram Analysis

Targeting angiotensinogen with RNA-based therapeutics

PURPOSE OF REVIEW

To summarize all available data on targeting angiotensinogen with RNA-based therapeutics as a new tool to combat cardiovascular diseases.

RECENT FINDINGS

Liver-targeted, stable antisense oligonucleotides and small interfering RNA targeting angiotensinogen are now available, and may allow treatment with at most a few injections per year, thereby improving adherence. Promising results have been obtained in hypertensive animal models, as well as in rodent models of atherosclerosis, polycystic kidney disease and pulmonary fibrosis. The next step will be to evaluate the optimal degree of suppression, synergy with existing renin-angiotensin-aldosterone system blockers, and to determine harmful effects of suppressing angiotensinogen in the context of common comorbidities, such as heart failure and chronic kidney disease.

SUMMARY

Targeting angiotensinogen with RNA-based therapeutics is a promising new tool to treat hypertension and diseases beyond. Their long-lasting effects are particularly exciting, and if translated to a clinical application of at most a few administrations per year, may help to eliminate nonadherence.

Thiazolidinedione-independent activation of peroxisome proliferator-activated receptor γ is a potential target for diabetic macrovascular complications

Macrovascular complications are responsible for the high morbidity and mortality in patients with diabetes. Peroxisome proliferator‐activated receptor γ (PPARγ) plays a central role in the process of adipocyte differentiation and insulin sensitization, and also possesses anti‐atherogenic effects. Recently, some statins, angiotensin II type 1 receptor blockers and calcium channel blockers have been reported to activate PPARγ. However, the impact of PPARγ activation on diabetic macrovascular complications is not fully understood. It has been reported that the activation of PPARγ by thiazolidinediones induces anti‐atherogenic effects in vascular cells, including monocytes/macrophages, endothelial cells and smooth muscle cells, in atherosclerotic animal models and in clinical studies. We have reported that hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), which are used for treatment of hypercholesterolemia, activate PPARγ and mediate anti‐atherogenic effects through PPARγ activation in macrophages. Also, telmisartan, an angiotensin type I receptor blocker, has been reported to have anti‐atherogenic effects through PPARγ activation. Furthermore, we have reported that nifedipine, a dihydropyridine calcium channel blocker, can activate PPARγ, thereby mediating anti‐atherogenic effects in macrophages. Therefore, statin therapy and part of anti‐hypertensive therapy might produce beneficial effects through PPARγ activation in hypercholesterolemic and/or hypertensive patients with diabetes, and PPARγ might be a therapeutic target for diabetic macrovascular complications. In the present review, we focus on the anti‐atherogenic effects of PPARγ and suggest potential therapeutic approaches to prevent diabetic macrovascular complications. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00182.x, 2012)

Estimated glomerular filtration rate reversal by blood pressure lowering in chronic kidney disease: Japan Multicenter Investigation for Cardiovascular DiseaseB CKD study

Patients are diagnosed as having chronic kidney disease (CKD) if estimated glomerular filtration rate (eGFR) is <60 mL/min/1.73 m(2) . Low eGFR is likely to increase the incidence of cardiovascular events and lead to dialysis. Therefore, it is important to prevent eGFR from decreasing eGFR. However, it still remains unknown whether antihypertensive therapy can prevent low eGFR from becoming even lower and improve eGFR in hypertensive patients with CKD. The authors analyzed the results of the Japan Multicenter Investigation for Cardiovascular DiseaseB (JMIC-B) and investigated the effects of antihypertensive therapy on eGFR. In hypertensive patients with CKD (eGFR <60), eGFR was significantly increased from 51.87±6.21 (n=98) to 57.55±19.00 (P<.001) after 3 years of antihypertensive therapy. In patients without CKD (eGFR ≥60), eGFR was significantly decreased from 91.84±23.27 (n=682) to 88.95±23.67 (P<.001). Regardless of the type of antihypertensive drugs used, eGFR was significantly increased in patients with CKD and was significantly decreased in patients without CKD. This paper shows that antihypertensive therapy can improve eGFR in hypertensive patients with CKD. J Clin Hypertens (Greenwich). 2012;00:00-00. ©2012 Wiley Periodicals, Inc.

Stable angina pectoris: the medical management of symptomatic myocardial ischemia

Coronary artery disease (CAD) remains an important cause of morbidity and mortality and is a serious public health problem. Over the last 4 decades there have been dramatic advances in the both the prevention and treatment of CAD. The management of CAD was revolutionized by the development of effective surgical and percutaneous revascularization techniques. In this review we discuss the importance of the medical management of symptomatic, stable angina. Medical management approaches to both the treatment and prevention of symptomatic myocardial ischemia are summarized. In Canada, organic nitrates, β-adrenergic blocking agents, and calcium channel antagonists have been available for the therapy of angina for more than 25 years. All 3 classes are of proven benefit in the improvement of symptoms and exercise capacity in patients with stable angina. Although there is no clear first choice within these classes of anti-anginal agents, the presence of prior or concurrent conditions (for example, prior myocardial infarction and/or hypertension) plays an important role in the choice of anti-anginal class in individual patients. For some patients, combinations of different anti-anginal agents can be effective; however it is recommended that this approach be individualized. Although not currently available in Canada, other classes of anti-anginal agents have been developed; their mechanism of action and clinical efficacy is discussed. Patients with stable angina have an excellent prognosis. Patients in this category who obtain relief from symptomatic myocardial ischemia may do well without invasive intervention.

Antioxidant effects of photodegradation product of nifedipine

Recently, increasing evidence suggests that the antihypertensive drug nifedipine acts as a protective agent for endothelial cells, and that the activity is unrelated to its calcium channel blocking. Nifedipine is unstable under light and reportedly decomposes to a stable nitrosonifedipine (NO-NIF). NO-NIF has no antihypertensive effect, and it has been recognized as a contaminant of nifedipine. The present study for the first time demonstrated that NO-NIF changed to a NO-NIF radical in a time-dependent manner when it interacted with human umbilical vein endothelial cells (HUVECs). The electron paramagnetic resonance (EPR) signal of NO-NIF radicals in HUVECs showed an asymmetric pattern suggesting that the radicals were located in the membrane. The NO-NIF radicals had radical scavenging activity for 1,1-diphenyl-2-picrylhydrazyl, whereas neither NO-NIF nor nifedipine did. In addition, the NO-NIF radical more effectively quenched lipid peroxides than NO-NIF or nifedipine. Furthermore, NO-NIF attenuated the superoxide-derived free radicals in HUVECs stimulated with LY83583, and suppressed iron-nitrilotriacetic acid (Fe-NTA)-induced cytotoxicity in rat pheochromocytoma (PC12) cells. Our findings suggest that NO-NIF is a candidate for a new class of antioxidative drugs that protect cells against oxidative stress.

Combination of angiotensin II receptor antagonist with calcium channel blocker or diuretic as antihypertensive therapy for patients with chronic kidney disease

We compared treatment with an angiotensin II receptor antagonist (ARB) and a calcium channel blocker (CCB) combination and a fixed-dose ARB and thiazide diuretic in 18 chronic kidney disease (CKD) patients. A randomized crossover study was performed using a fixed-dose combination of losartan-hydrochlorothiazide or losartan combined with controlled-release nifedipine. Both systolic blood pressure (SBP) and diastolic blood pressures (DBPs) were lower during the nifedipine period than during the diuretic period. No significant difference was observed in urinary albumin excretion, but the estimated glomerular filtration rate was higher in the nifedipine than in the diuretic period. Serum uric acid and low-density lipoprotein cholesterol were higher in the diuretic than in the nifedipine period. A significantly low cardio-ankle vascular index, an index of arterial wall stiffness, was observed in the nifedipine period. A combination of ARB and a controlled-release nifedipine at 20-40 mg used showed a superior antihypertensive effect in CKD patients compared to a fixed-dose combination of losartan 50 mg-hydrochlorothiazide 12.5 mg in terms of blood control. The former combination is considered advantageous for maintaining renal function and artery wall elasticity without influencing uric acid or lipid metabolism.

Angiotensin II receptor blocker and long-acting calcium channel blocker combination therapy decreases urinary albumin excretion while maintaining glomerular filtration rate

Microalbuminuria is a recognized risk factor and predictor for cardiovascular events in patients with hypertension. We analyzed changes in hypotensive effect, urinary albumin excretion (UAE) and estimated glomerular filtration rate (eGFR) in subjects with hypertension and microalbuminuria as a subanalysis of the results of the Nifedipine and Candesartan Combination (NICE-Combi) Study. A total of 86 subjects with essential hypertension with microalbuminuria (UAE <300 mg g(-1) creatinine) were randomly assigned in a double-blind manner to a combination therapy group (standard-dose candesartan at 8 mg per day plus controlled-release (CR) nifedipine 20 mg per day) (n=42) or an up-titrated monotherapy group (candesartan 12 mg per day) (n=44) for 8 weeks of continuous treatment after initially receiving standard-dose candesartan (8 mg per day) monotherapy for 8 weeks (initial treatment). After 8weeks, blood pressure (BP) was significantly reduced in both groups compared with at the end of initial treatment. UAE also showed a significant decrease in the combination therapy group, while there was no significant change of eGFR in either group. A significant positive correlation was seen between BP reduction and UAE after 8 weeks of double-blind treatment in both groups, whereas no significant association was found between ΔUAE and ΔeGFR in either group. These findings show that combination therapy with standard-dose candesartan and nifedipine CR is more effective than up-titrated candesartan monotherapy for reducing BP and improving UAE while maintaining eGFR, and strongly suggest that the combination of an angiotensin II receptor blocker and long-acting calcium channel blocker is beneficial in patients with hypertension and microalbuminuria.

Protective effect of photodegradation product of nifedipine against tumor necrosis factor alpha-induced oxidative stress in human glomerular endothelial cells

Recently, increasing evidence suggests that the antihypertensive drug nifedipine acts as a protective agent for endothelial cells, and that the activity is unrelated to its calcium channel blocking. Nitrosonifedipine (NO-NIF) is metabolically and photochemically produced from nifedipine, and NO-NIF has been recognized as a contaminant of nifedipine because it has no antihypertensive effect. Treatment of tumor necrosis factor-α (TNF-α) suppressed the cell viability and facilitated the expression of Inter-Cellular Adhesion Molecule 1(ICAM-1) in human glomerular endothelial cells (HGECs) though, pretreatment of NO-NIF significantly recovered the TNF-α-induced cell damage to the same extent as Trolox-C did, and suppressed the ICAM-1 expression in a concentration dependent manner. In addition, NO-NIF inhibited the cell toxicity induced by cumene hydroperoxide, which hampers the integrity of cell membrane through oxidative stress, as effective as Trolox-c. These data suggest that NO-NIF is a candidate for a new class of antioxidative drug that protect cells against oxidative stress in glomerular endothelial cells.

Use of dihydropyridine calcium channel blockers in the management of hypertension in Eastern Asians: a scientific statement from the Asian Pacific Heart Association

Dihydropyridine calcium channel blockers (CCBs) are widely prescribed for the management of hypertension in Eastern Asians. In this study, the Asian Pacific Heart Association's Writing Committee reviewed randomized controlled trials that were conducted in the Eastern Asian region and compared a CCB with an antihypertensive drug of another class. These trials studied ambulatory blood pressure, measures of target organ damage and cardiovascular events as outcomes. Eleven trials studied ambulatory blood pressure in hypertensive patients and demonstrated that the 24-h blood pressure reduction with CCBs was greater than with other classes of antihypertensive drugs, with a weighted mean difference of 5 mm Hg systolic and 3 mm Hg diastolic. Twelve trials that studied various measurements of target organ damage in hypertensive patients produced inconsistent results when comparing CCBs and other classes of antihypertensive drugs. Four trials that studied the hard outcomes had limited power, but confirmed the findings of previous placebo-controlled trials in the region and actively controlled trials in Europe and North America; they suggested that CCBs provided superior protection against stroke and that some agents, such as amlodipine, also provided similar protection against myocardial infarction. In conclusion, CCBs should be recommended as a preferred drug for the management of hypertension in the Eastern Asian region to improve blood pressure control and to confront the aggravating epidemic of stroke and coronary heart disease.

Nifedipine Induces Peroxisome Proliferator-Activated Receptor-γ Activation in Macrophages and Suppresses the Progression of Atherosclerosis in Apolipoprotein E-Deficient Mice

Objective— Nifedipine, an L-type calcium channel blocker, protects against the progression of atherosclerosis. We investigated the molecular basis of the antiatherosclerotic effect of nifedipine in macrophages and apolipoprotein E-deficient mice.

Methods and Results— In macrophages, nifedipine increased peroxisome proliferator-activated receptor-γ (PPARγ) activity without increasing PPARγ-binding activity. Amlodipine, another L-type calcium channel blocker, and 1,2-bis-(o-aminophenoxy)-ethane-N,N,-N′,N′-tetraacetic acid tetraacetoxy-methyl ester (BAPTA-AM), a calcium chelator, decreased PPARγ activity, suggesting that nifedipine does not activate PPARγ via calcium channel blocker activity. Inactivation of extracellular signal-regulated kinase 1/2 suppressed PPARγ2-Ser112 phosphorylation and induced PPARγ activation. Nifedipine suppressed extracellular signal-regulated kinase 1/2 activation and PPARγ2-Ser112 phosphorylation, and mutating PPARγ2-Ser112 to Ala abrogated nifedipine-mediated PPARγ activation. These results suggested that nifedipine inhibited extracellular signal-regulated kinase 1/2 activity and PPARγ2-Ser112 phosphorylation, leading to PPARγ activation. Nifedipine inhibited lipopolysaccharide-induced monocyte chemoattractant protein-1 expression and induced ATP-binding cassette transporter A1 mRNA expression, and these effects were abrogated by small interfering RNA for PPARγ. Furthermore, in apolipoprotein E-deficient mice, nifedipine treatment decreased atherosclerotic lesion size, phosphorylation of PPARγ2-Ser112 and extracellular signal-regulated kinase 1/2, and monocyte chemoattractant protein-1 mRNA expression and increased ATP-binding cassette transporter A1 expression in the aorta.

Conclusion— Nifedipine unlike amlodipine inhibits PPARγ-Ser phosphorylation and activates PPARγ to suppress monocyte chemoattractant protein-1 expression and induce ATP-binding cassette transporter A1 expression in macrophages. These effects may induce antiatherogenic effects in hypertensive patients.

Influence of nifedipine coat-core and amlodipine on systemic arterial stiffness modulated by sympathetic and parasympathetic activity in hypertensive patients

The aim of this study was to compare the effects of nifedipine coat-core (once daily formulation) and amlodipine on systemic arterial stiffness in patients with hypertension. Study drugs were assigned by the randomized open-label crossover method. After the blood pressure was maintained below 130/85 mm Hg for 8 months by treatment with either drug in 48 hypertensive patients (aged 63.2+/-6.9 years; 64.5% men), they were switched to the other drug for another 8 months. The blood pressure, heart rate, plasma catecholamine level and brachial-ankle pulse wave velocity were measured before and after a bicycle ergometer testing. Heart rate recovery was calculated from the change of the heart rate after treadmill exercise testing. The high-frequency and low-frequency components of the heart rate variability spectrum were analyzed from 24-h Holter electrocardiograms. The change of blood pressure after exercise testing showed no significant difference between the two medications. However, the increases of heart rate, noradrenalin and branchial-ankle pulse wave velocity after exercise were significantly smaller with nifedipine treatment than with amlodipine (P=0.0472, P=0.006 and P=0.0472, respectively). Heart rate recovery was significantly faster with nifedipine treatment (P=0.0280). The nighttime high-frequency component of heart rate variability was significantly larger after nifedipine treatment than after amlodipine (P=0.0259), while the nighttime low/high-frequency ratio was significantly smaller with nifedipine (P=0.0429). Nifedipine reduced functional arterial stiffness and improved heart rate recovery by altering the autonomic activity balance in hypertensive patients.

Drug discovery for overcoming chronic kidney disease (CKD): development of drugs on endothelial cell protection for overcoming CKD

Chronic kidney disease (CKD) is becoming a major public health problem worldwide. It is important to protect endothelial function in CKD treatment because injury of the endothelium is a critical event for the generation and progression of CKD. Recently, clinical studies showed that nifedipine, an antihypertensive drug, acts as a protective agent of endothelial cells (ECs). Nifedipine is reported to partially decompose to a nitrosonifedipine that has high reactivity against lipid-derived radicals in vitro. However, it is still unclear whether nitrosonifedipine is a biologically active agent against endothelial injury. We observed that nitrosonifedipine was converted to radical form by reaction with cultured ECs. The cumene hydroperoxide mediated cytotoxity was reduced by nitrosonifedipine in cultured human glomerular ECs (HGECs). Also nitrosonifedipine suppressed the expression of TNF-alpha-induced intercellular cell adhesion molecule-1 in HGECs. Chronic administration of N(omega)-nitro-L-arginine methyl ester (L-NAME) caused systemic arterial hypertension, endothelial injury, and renal dysfunction. In L-NAME-induced hypertensive rats, nitrosonifedipine treatment improved not only the acetylcholine-induced vasodilation of the aortic rings, but also renal dysfunction such as increasing the levels of serum creatinine and urinary protein excretion. Our preliminary data suggest that nitrosonifedipine is a new and useful drug for the treatment of CKD involving ameliorating effects on EC disorder.

Review of nifedipine GITS in the treatment of high risk patients with coronary artery disease and hypertension

Nifedipine is a dihydropyridine calcium-channel blocker (CCB) introduced approximately 30 years ago for the prophylaxis of angina symptoms, and then later utilized as an anti-hypertensive agent. In the 1990s, several meta-analyses and a case-control study were published which raised concern regarding increased mortality and increased risk for myocardial infarction with short-acting nifedipine. Further evaluation of these meta-analyses and case control study underscores some important limitations and the need to further elucidate the role of this class of medications in high-risk patients. Until 2000, there was a paucity of data on the long-term effects as well as the long-term outcomes of CCBs in the treatment of stable coronary disease or in patients with manifestations of the disease such as hypertension or angina. While it has been well established that nifedipine and other dihydropyridines lower blood pressure and improve symptoms of angina, several studies were designed to evaluate the effect of dihydropyridines on "hard" outcomes, specifically cardiovascular and cerebrovascular events. In this review, we describe the clinical studies evaluating the use of nifedipine when compared to placebo as well as other anti-hypertensive therapies in an attempt to identify the most appropriate place in therapy for this class of medications and to further clarify its utilization in high-risk patients.

[Anti-inflammatory effect of nifedipine and vasculoprotection]

Many clinical reports suggest that nifedipine has vascular protective actions independent of its antihypertensive action; however, the precise mechanism for such a protective effect has not yet been elucidated. The effect of nifedipine on the pro-arteriosclerotic monocyte chemoattractant protein (MCP)-1 expression in the blood vessel wall, was evaluated since the inflammatory markers are raised with arteriosclerosis. Nifedipine inhibited MCP-1 expression by inhibiting nuclear factor (NF)-kappaB activation. Furthermore, nifedipine inhibited vascular smooth muscle growth and improved vascular remodeling through these mechanisms. Thus, these data suggest that vascular protective action of nifedipine was at least partially independent of Ca2+ channel blockade and mediated by an anti-inflammatory effect.

Nifedipine retard prevents hospitalization for angina pectoris better than angiotensin-converting enzyme inhibitors in hypertensive Japanese patients with previous myocardial infarction (JMIC-B substudy)

OBJECTIVES AND BACKGROUND

We previously reported that nifedipine retard showed comparable efficacy to angiotensin-converting enzyme (ACE) inhibitors for the prevention of cardiac events in hypertensive patients with coronary artery disease during the Japan Multicenter Investigation for Cardiovascular Diseases B study. In the nifedipine group, patients with a history of myocardial infarction (MI) showed a significant reduction in hospitalization for angina pectoris compared with the ACE inhibitor group. We investigated whether this difference was related to the progression of coronary arteriosclerosis.

METHODS

To evaluate coronary arteriosclerosis, we performed coronary angiography (CAG) and a quantitative analysis of coronary angiograms.

RESULTS

The cumulative incidence of hospitalization for angina was significantly lower in the nifedipine group (log-rank test P = 0.013). The etiology of angina requiring hospitalization was determined on the basis of CAG findings. Its incidence secondary to the development of new lesions or the progression of existing lesions was significantly lower in the nifedipine group than in the ACE inhibitor group (log-rank test P = 0.042 and P = 0.028, respectively). Using quantitative coronary analysis, changes in the coronary artery luminal diameter were compared between the nifedipine and ACE inhibitor groups. The minimum coronary lumen diameter did not show a significant change in the nifedipine group, whereas it decreased significantly in the ACE inhibitor group (paired t-test P = 0.002), and there was a significant difference between the two groups by analysis of covariance (P = 0.047).

CONCLUSION

These results indicate that nifedipine more effectively prevented admission for angina pectoris by inhibiting the progression of coronary artery disease in patients with a history of MI.

Calcium channel blockers in the spectrum of antihypertensive agents

Calcium channel blockers (CCBs) are widely used in the treatment of hypertension. Through blood pressure reduction, and possibly other mechanisms such as antioxidative effects, they may play a role in diminishing the risk for a variety of cardiovascular outcomes. The combination of CCBs with other newer antihypertensive agents such, as ACE inhibitors and angiotensin receptor blockers, may provide complementary effects on risk reduction in cardiovascular adverse events and renal disease. Although the efficacy of CCBs as antihypertensive agents has been adequately demonstrated, there have been concerns regarding the use of short acting dihydropyridines after acute myocardial infarction. There have also been questions about the role of CCBs with regards to other antihypertensive agents in renal disease. For example, differential effects of dihydropyridine and non-dihydropyridine CCBs may affect progression of renal disease and risk for diabetes. Certain precautions involving drug interactions are needed because of the effects of CCBs on the CYP450 enzyme systems.

Modified-release nifedipine: a review of the use of modified-release formulations in the treatment of hypertension and angina pectoris

Nifedipine is a dihydropyridine calcium channel antagonist with predominantly vasodilatory activity. Modified-release formulations of nifedipine are effective antihypertensive and antianginal therapies and are generally well tolerated. Among the available formulations, those that produce a gradual increase in plasma nifedipine concentration, which is then sustained over a 24-hour period, are preferred, as they cause a gradual onset of vasodilatation and avoid baroreflex sympathetic activation (for example, nifedipine gastrointestinal therapeutic system [GITS] and a Japanese controlled-release formulation). Modified-release nifedipine had beneficial effects on a number of markers of vascular function, and nifedipine GITS reduced the need for coronary procedures in patients with coronary artery disease. In patients with hypertension, nifedipine GITS and nifedipine retard had beneficial effects on the overall incidence of major cardiovascular events, as did nifedipine retard in patients with concurrent hypertension and coronary artery disease.

Role of the renin-angiotensin-aldosterone system and proinflammatory mediators in cardiovascular disease

Inflammation is a key mechanism in the initiation, progression, and clinical sequelae of cardiovascular diseases (CVDs), including atherosclerosis, nephropathy, and cardiomyopathy. Angiotensin II, the major effector peptide of the renin-angiotensin-aldosterone system (RAAS), plays a significant role in the advent and perpetuation of these inflammatory diseases, most notably in atherogenesis. Consequently, suppression of the influence of angiotensin II by angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers may reduce or potentially reverse atherosclerosis and other inflammation-associated CVDs. Angiotensin II receptor blockers and angiotensin-converting enzyme inhibitors exert anti-inflammatory actions and prevent or reduce the development of atherosclerosis in animal models. Clinically, RAAS suppression reduces common carotid and femoral artery intima-media thickness, thus indicating moderation of the vascular disease process. These clinical benefits likely involve restraint of the deleterious effects of angiotensin II in addition to, or independent of, lowering blood pressure. Increasing evidence that the detection and monitoring of vascular inflammation are important tools in the management of atherosclerosis also implicates the RAAS in this pathogenic process. Inflammatory molecules such as intercellular adhesion molecule-1, vascular cell adhesion molecule-1, monocyte chemoattractant protein-1, tumor necrosis factor-alpha, and C-reactive protein have potential diagnostic and prognostic values in CVD and are modified by angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers. Monitoring these markers may be crucial for determining which agents, or combinations of agents, will result in the most clinically beneficial outcomes for patients. Large-scale trials are still required to determine the effects of the long-term suppression of inflammation on CVDs through the use of RAAS modulating agents, as well as to determine how closely markers of inflammatory activity may correlate with CVD outcomes.