Are all antihypertensive drug classes equal in reducing left ventricular hypertrophy?

Effect of 24-Week Treatment with Telmisartan on Myocardial Structure and Function: Relationship to Insertion/Deletion Polymorphism of the Angiotensin-Converting Enzyme Gene

The aim of the present study was to assess the effect of treatment with the angiotensin II receptor blocker telmisartan for 24 weeks on myocardial structure and function in patients with essential hypertension, and the relationship between this effect and the structural polymorphism of the angiotensin-converting enzyme (ACE) gene. Thirty-five patients with essential hypertension and left ventricular hypertrophy (LVH) without other associated morbidity were included in an open-label, non-comparative study. The patients were treated with telmisartan 40-80 mg once daily. In the final analysis, there were 29 patients who received the full course of treatment and were evaluated echocardiographically before and after treatment by the same blinded investigator, and myocardial structure and function were analysed. The myocardial mass of the left ventricle was determined in M-mode. Assessment of diastolic function of transmitral blood flow was performed using pulsed Doppler echocardiography. All patients were genotyped for insertion/deletion (I/D) polymorphism of the ACE gene. Telmisartan produced a significant reduction in left ventricular mass index from 140.4 ± 48.6 to 128.7 ± 40.6 g/m2 that was accompanied by an improvement in characteristics of diastolic function. The decrease in LVH was more significant in the ID genotype group than in the II and DD groups. Thus, prolonged treatment with telmisartan is accompanied by an improvement in myocardial structure, expressed as a reduction in left ventricular mass and function that is more marked in patients with ID genotype of the ACE gene.

Rationale and Design of the Cardiac Magnetic Resonance Imaging Substudy of the ONTARGET Trial Programme

Angiotensin-converting enzyme (ACE) inhibitors have been shown to improve cardiovascular disease outcomes in high-risk patients, but evidence for the cardioprotective effects of angiotensin II receptor blockers (ARBs) is less extensive. The ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET) and the parallel Telmisartan Randomized AssessmeNt Study in aCE iNtolerant subjects with cardiovascular Disease (TRANSCEND) - which together form The ONTARGET Trial Programme – are long-term, large-scale, double-blind, multinational outcome studies with the primary objectives of determining if the combination of the ARB telmisartan 80 mg and the ACE inhibitor ramipril 10 mg is more effective than ramipril 10 mg alone, and if telmisartan is at least as effective as ramipril (in the case of ONTARGET), and if telmisartan is superior to placebo (in the case of TRANSCEND), in providing cardiovascular protection for high-risk patients. A pre-defined substudy is being conducted within The ONTARGET

Trial Programme to compare the effects of these agents, alone and in combination, on cardiac structure and function. The substudy overcomes criticisms of many previous studies, which have been performed in small numbers of patients using suboptimal methodology, by evaluating changes in left ventricular structure and function using sophisticated technology provided by magnetic resonance imaging (MRI). Some 300 randomized patients within ONTARGET, recruited from selected centres in Australia, Canada, Germany, Hong Kong, New Zealand and Thailand, will have MRI undertaken at baseline and at 2-year follow-up. As this method of assessing left ventricular dysfunction is somewhat time-consuming, expensive and complex, and in the light of current interest in the role of B-type natriuretic peptide (BNP) as a simple, inexpensive diagnostic and prognostic tool, the substudy will also examine whether changes in BNP during follow-up correlated with changes in left ventricular dysfunction.

Perindopril/indapamide combination in the first-line treatment of hypertension and end-organ protection

This article examines evidence-based findings in the literature on the efficacy of perindopril 2 mg/indapamide 0.625 mg, a first-line, low-dose antihypertensive drug combination. In regulatory Phase II and III trials, perindopril/indapamide significantly lowered blood pressure compared with other first-line therapies (atenolol, losartan and irbesartan). This was also the case in STRAtegies of Treatment in Hypertension: Evaluation, a postregistration study versus current monotherapies and stepped-care therapy with different classes of antihypertensive agents. The efficacy/safety ratio (both clinical and with regard to laboratory parameters) of perindopril/indapamide was good. Perindopril/indapamide provides additional antihypertensive efficacy compared with each component used alone and with current monotherapies, with major efficacy on systolic blood pressure, an important predictor of cardiovascular risk. It also reduces pulse pressure, an independent cardiovascular risk factor, large-vessel arterial stiffness and microcirculatory alterations. The fixed dosage of a once-daily tablet, ensures optimal ease of use and enhances patient compliance. Perindopril/indapamide also reduces target organ damage in patients at high cardiovascular risk, such as patients with cardiac hypertrophy and Type 2 diabetics with albuminuria. These benefits, together with the good efficacy/tolerability ratio, fulfill the requirements of the European Society of Hypertension and of the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure guidelines for low-dose, first-line combination therapy in hypertension.

Effects of valsartan or ramipril addition to amlodipine/hydrochlorothiazide combination on left ventricular mass in diabetic hypertensive patients with left ventricular hypertrophy

OBJECTIVE

The objective of this study was to compare valsartan or ramipril addition to amlodipine + hydrochlorothiazide (HCTZ) on blood pressure (BP) and left ventricular hypertrophy (LVH) in hypertensive diabetic patients with LVH.

RESEARCH DESIGN AND METHODS

293 patients were treated with amlodipine 10 mg + HCTZ 12.5 combination and then randomized to receive valsartan 160 mg or ramipril 5 mg, in addition to the previous therapy, for 1 year.

MAIN OUTCOME MEASURES

Clinic BP was measured every month; echocardiographic assessments were performed at the end of the placebo period, both before the randomization and after 1-year of triple combination therapy.

RESULTS

Both triple regimens similarly reduced SBP/DBP values (-13.5/10.9 mm Hg in the valsartan group and -13.4/10.4 mm Hg in the ramipril group). Triple combination including valsartan better reduced LVMI (-20.1%, p < 0.001), interventricular septal thickness (IVST) (-20.3%, p < 0.001) and left ventricular posterior wall thickness (PWT) (-16.3%, p < 0.001), compared with triple combination including ramipril (-14%, p < 0.01; -16.2%, p < 0.001 and -9%, p < 0.01, respectively); the difference between treatments being statistically significant (p < 0.05). Triple combination with valsartan gave a greater increase of E/A ratio (p < 0.05 between groups).

CONCLUSIONS

Valsartan addition to dual therapy with amlodipine + HCTZ was more effective than ramipril addition in reducing LVH.

Losartan and amlodipine on myocardial structure and function: a prospective, randomized, clinical trial

AIMS

To compare the effects of losartan and amlodipine on myocardial structure and function in hypertensive patients with Type 2 diabetes and left ventricular hypertrophy.

METHODS

After a 4-week placebo period, patients were randomized to losartan 50 mg (n = 90) or amlodipine 5 mg (n = 91) for 12 months, with a doubling of the dose in patients who did not respond after 4 weeks. Blood pressure was measured in the clinic every month, while conventional echocardiography and acoustic densitometry (integrated backscatter analysis) were performed at the end of the placebo period and after 12 months of treatment.

RESULTS

Both drugs reduced systolic/diastolic blood pressure to a comparable extent. Losartan significantly reduced left ventricular mass index (-19%, P < 0.001), interventricular septal thickness (-16.6%, P < 0.01) and left ventricular posterior wall thickness in diastole (-13.7%, P < 0.01). Amlodipine also decreased such measurements (-10%, P < 0.01 for left ventricular mass index, -9.3%, P < 0.05 for interventricular septal thickness in diastole and -10.1%, P < 0.05 for posterior wall thickness in diastole), but to a lesser extent than losartan. Both drugs significantly increased the ratio of peak filling velocity at early diastole to that at atrial contraction (E/A ratio) and decreased isovolumetric relaxation time: +13.7% and -8.5% with losartan,(both P < 0.01), and +7.9% and -4.9%, with amlopidine (both P < 0.05). Losartan, but not amlodipine, significantly reduced the relative integrated backscatter compared to baseline of the intraventricular septum (-10%, P < 0.01), and of the left ventricular posterior wall (-12%, P < 0.01), while increasing the cyclic variation of integrated backscatter of both the intraventricular septum (+35%, P < 0.001) and the left ventricular posterior wall (+32%, P < 0.001).

CONCLUSIONS

Losartan provided a greater attenuation of left ventricular hypertrophy than amlodipine, seemingly as a result of a greater reduction of myocardial fibrosis.

Effects of the combinations of amlodipine/valsartan versus losartan/hydrochlorothiazide on left ventricular hypertrophy as determined with magnetic resonance imaging in patients with hypertension

BACKGROUND

Left ventricular hypertrophy (LVH), a marker of cardiac end-organ damage, is frequently found in patients with arterial hypertension and is associated with cardiovascular and cerebrovascular morbidity and mortality. Therefore, LVH regression is an important treatment goal. For amlodipine plus valsartan (A/V) no specific study on LVH has been reported to date.

METHODS

Prospective, open-label, randomized parallel-group study. Patients with essential hypertension and LVH were randomized to 52-week treatment with A/V 10/160 mg (n = 43) or the active comparator losartan/HCT 100/25 mg (L/H, n = 47). Add-on medication was allowed in case of inadequate blood pressure control. LV parameters were measured by cardiovascular magnetic resonance imaging (MRI), and adjudicated in a blinded manner. Study identifiers were NCT00446563 and EudraCT 2006-001977-17.

RESULTS

In addition to the study treatment, 35% of patients in the A/V group and 49% in the L/H group received additional antihypertensive medication. Compared to baseline, both treatments reduced measures of LVH significantly after 52 weeks (e.g. LV mass index in the A/V group from 64.7 g/m(2) by -3.5 g/m(2), in the L/H group from 69.1 g/m(2) by -4.4 g/m(2), p < 0.01 for both). LV ejection fraction and LV volumes were not significantly changed by any regimen. A/V and L/H treatments were well tolerated.

CONCLUSIONS

Both regimen were effective in reducing LV mass compared to baseline and were well tolerated.

Blood pressure control determines improvement in diastolic dysfunction in early hypertension

BACKGROUND

Diastolic dysfunction is common in early hypertension. We hypothesized that improvement in diastolic dysfunction is blood pressure (BP) dependent and may occur early with treatment in newly diagnosed untreated hypertensive patients.

METHODS

Forty untreated hypertensive subjects (age 52 +/- 1.4 years, mean +/- s.e.m.) with diastolic dysfunction based on Canadian Consensus Guidelines, received either bendroflumethiazide 2.5 mg (1.25 mg for the first month), or candesartan 16 mg (8 mg for the first month). Left ventricular (LV) structure and function, early diastolic velocity (E') and systolic velocity, and systolic myocardial velocity (Sm) were assessed echocardiographically using M-mode, 2-dimensional, and tissue Doppler imaging (TDI) before and at 1 and 3 months following treatment.

RESULTS

Antihypertensive treatment reduced BP significantly at 3 months (168 +/- 2/97 +/- 1-143 +/- 2/86 +/- 1 mm Hg, P < 0.0001). Both drugs had similar and significant effects on TDI E' which increased from 7.8 +/- 0.2 to 10 +/- 0.3 cm/s (P < 0.001). The improvement in TDI E' was independent of LV mass index (LVMI) regression but was significantly related to the improvement in Sm (r = 0.73, P < 0.0001) and the fall in systolic BP (R = 0.51, P < 0.001). Normalization of diastolic function was associated with better control of BP (130 +/- 4/81 +/- 2 mm Hg vs. 149 +/- 2/88 +/- 1 mm Hg, P < 0.05). In a stepwise regression model, reduction in systolic BP (P < 0.001) and TDI Sm (P < 0.0001) emerged as independent determinants of improvement in TDI E' with no contribution from age, gender or change in relative wall thickness (RWT) (R(2) = 0.68, P < 0.0001).

CONCLUSIONS

Achieving good BP control and enhancement in systolic function determines the improvement in diastolic function in early hypertension.

Exploiting cGMP-based therapies for the prevention of left ventricular hypertrophy: NO* and beyond

Left ventricular hypertrophy (LVH), an increased left ventricular (LV) mass, is common to many cardiovascular disorders, initially developing as an adaptive response to maintain myocardial function. In the longer term, this LV remodelling becomes maladaptive, with progressive decline in LV contractility and diastolic function. Indeed LVH is recognised as an important blood-pressure independent predictor of cardiovascular morbidity and mortality. The clinical efficacy of current treatments for LVH is reduced, however, by their tendency to slow disease progression rather than induce its reversal, and thus the development of new therapies for LVH is paramount. The signalling molecule cyclic guanosine-3',5'-monophosphate (cGMP), well-recognised for its role in regulating vascular tone, is now being increasingly identified as an important anti-hypertrophic mediator. This review is focused on the various means by which cGMP can be stimulated in the heart, such as via the natriuretic peptides, to exert anti-hypertrophic actions. In particular we address the limitations of traditional nitric oxide (NO*) donors in the face of the potential therapeutic advantages offered by novel alternatives; NO* siblings, ligands of the cGMP-generating enzymes, soluble (sGC) and particulate guanylyl cyclases (pGC), and phosphodiesterase inhibitors. Further impact of cGMP within the cardiovascular system is also discussed with a view to representing cGMP-based therapies as innovative pharmacotherapy, alone or concurrent with standard care, for the management of LVH.

Carvedilol in hypertension treatment

Although β-blockers have been previously shown to effectively reduce blood pressure (BP) and have been used for hypertension treatment for over 40 years, their effect on cardiovascular morbidity and mortality in hypertensive patients remains controversial and its use in uncomplicated hypertension is currently under debate. However, data on the above field derive mainly from studies which were conducted with older agents, such as atenolol and metoprolol, while considerable pharamacokinetic and pharmacodynamic heterogeneity is present within the class of β-blockers. Carvedilol, a vasodilating non-cardioselective β-blocker, is a compound that seems to give the opportunity to the clinician to use a cardioprotective agent without the concerning hemodynamic and metabolic actions of traditional β-blocker therapy. In contrast with conventional β-blockers, carvedilol maintains cardiac output, has a less extended effect on heart rate and reduces BP by decreasing vascular resistance. Further, several studies has shown that carvedilol has a beneficial or at least neutral effect on metabolic parameters, such as glycemic control, insulin sensitivity, and lipid metabolism, suggesting that they could be used in subjects with the metabolic syndrome or diabetes without negative consequences. This article summarizes the distinct pharmacologic, hemodynamic, and metabolic properties of carvedilol in relation to conventional β-blockers, attempting to examine the potential use of this agent for hypertension treatment.

Induction of vascular atrophy as a novel approach to treating restenosis. A review

Regardless of the type of arterial reconstruction, luminal narrowing (stenosis or restenosis) develops in approximately one third of the vessels. In the past, the focus of research has been on the mechanisms of stenosis (intimal hyperplasia, pathologic remodeling) and pharmacologic approaches to prevention. An alternative approach is to induce intimal atrophy after luminal narrowing has developed, thus limiting treatment to only those patients that develop a problem. This approach to treat established disease by reducing wall mass through induction of cell death and extracellular matrix removal would be particularly useful for treating stenosis in synthetic bypass grafts or stented vessels, in which intimal hyperplasia is the primary mechanism of stenosis. This approach may be applicable as well to other vascular proliferative disorders, such as pulmonary hypertension and chronic transplant arteriopathy. Proof of principle has been shown in experiments with antibodies to platelet-derived growth factor (PDGF) receptors that cause neointimal regression in baboon polytetrafluoroethylene (PTFE) grafts and with angiotensin-converting enzyme inhibitors that induce medial atrophy in hypertensive arteries. Possible molecular targets could include PDGF receptors, A20, and BMP4. Further studies are needed to determine the utility of such a therapeutic approach to vascular disease.

Adjuvant strategies for prevention of glomerulosclerosis

The glomerulosclerosis which frequently complicates diabetes and severe hypertension is mediated primarily by increased mesangial production and activation of transforming growth factor-beta (TGF-beta), which acts on mesangial cells to boost their production of matrix proteins while suppressing extracellular proteolytic activity. Hyperglycemia and glomerular hypertension work in various complementary ways to stimulate superoxide production via NADPH oxidase in mesangial cells; the resulting oxidant stress results in the induction and activation of TFG-beta. Nitric oxide, generated by glomerular capillaries and by mesangial cells themselves, functions physiologically to oppose mesangial TGF-beta overproduction; however, NO bioactivity is compromised by oxidant stress. In addition to low-protein diets and drugs that suppress angiotensin II activity, a variety of other agents and measures may have potential for impeding the process of glomerulosclerosis. These include vitamin E, which blunts the rise in mesangial diacylglycerol levels induced by hyperglycemia; statins and (possibly) policosanol, which down-regulate NADPH oxidase activity by diminishing isoprenylation of Rac1; lipoic acid, whose potent antioxidant activity antagonizes the impact of oxidant stress on TGF-beta expression; pyridoxamine, which inhibits production of advanced glycation endproducts; arginine, high-dose folate, vitamin C, and salt restriction, which may support glomerular production of nitric oxide; and estrogen and soy isoflavones, which may induce nitric oxide synthase in glomerular capillaries while also interfering with TGF-beta signaling. Further research along these lines may enable the development of complex nutraceuticals which have important clinical utility for controlling and preventing glomerulosclerosis and renal failure. Most of these measures may likewise reduce risk for left ventricular hypertrophy in hypertensives, inasmuch as the signaling mechanisms which mediate this disorder appear similar to those involved in glomerulosclerosis.

What can be learned from the experience with the fixed low-dose combination of perindopril/indapamide in the treatment of hypertension?

The association of low doses of perindopril and indapamide in a single pill has been developed to meet the criteria required for a fixed-dose combination to be used as first-line therapy. The experience accumulated so far has demonstrated a greater antihypertensive efficacy of this preparation compared with various monotherapies, but not at the expense of a worsening of tolerability. The perindopril/indapamide combination is particularly effective in lowering systolic and pulse blood pressure. Starting treatment with this fixed-dose combination improves arterial stiffness and allows a better regression of cardiac hypertrophy than angiotensin-converting enzyme-inhibition or beta-adrenoceptor blockade alone. In hypertensive patients with Type 2 diabetes, a greater reduction of urinary albumin excretion can be obtained with the perindopril/indapamide association compared with an angiotensin-converting enzyme inhibitor administered as monotherapy. There is evidence that a first-line management of hypertension based on a low-dose perindopril/indapamide combination can provide a better efficacy/safety ratio than other well-established therapeutic strategies.

Rethinking the renin-angiotensin system and its role in cardiovascular regulation

Angiotensin-converting enzyme (ACE) plays a pivotal role in the renin-angiotensin system (RAS) and ACE-inhibitors are widely used in several clinical conditions, including hypertension and heart failure. Recently, a homologue of ACE, ACE(2) has been discovered. Both ACE and ACE(2) are emerging as key enzymes of the RAS, where ACE(2) may play a role as negative regulator of ACE. Moreover, ACE(2) appears to be an important enzyme outside the classical RAS, as it hydrolyzes apelins, dynorphin A 1-13, des-Arg-bradykinin and other peptide substrates. The precise interplay between tissue ACE, ACE(2), and their substrates and by-products are presently still unclear.ACE-inhibitors reduce angiotensin II formation and bradykinin degradation, but do not inhibit ACE(2) activity. Moreover, ACE-inhibitors differ in their affinity for tissue ACE, and it has been suggested that tissue ACE affinity might be responsible for some of the beneficial properties of these drugs. ACE-inhibitors also increase nitric oxide availability, and activate several kinases that may regulate protein synthesis by interacting with the nucleus of the cells (outside-in signaling). The outside-in signaling may also be activated by bradykinin itself. Although, the precise significance of the outside-in signaling is still unclear, this new role of ACE-inhibitors may represent a discriminant factor versus angiotensin II receptors antagonists. This mini review will summarize some new aspects concerning the recently discovered biological functions of RAS and in particular of ACE, ACE(2) and ACE-inhibitors in cardiovascular system.

Advantages of blood pressure optimization

Lowering blood pressure (BP) reduces cardiovascular events, but aggressive BP management may not be advantageous. Optimal BP control (target: <120/80 mm Hg) and conventional BP control (target: <140/90 mm Hg) were compared in patients with hypertension in terms of target-organ damage and tolerability. A total of 23 patients with hypertension were randomly assigned to optimal versus conventional therapy for 6 months. Therapy was initiated with lercanidipine 10 mg/day. For BP control, the dose could be doubled or other drugs added. Three indices of target-organ damage were studied: left ventricular mass (LVM) index, flow-mediated dilatation (FMD) of the brachial artery, and 24-hour urinary albumin excretion. The BP decreased markedly by 21.3+/-3.4/13.2+/-1.7 mm Hg in the conventional therapy group and by 26.6+/-3.6/17.9+/-1.5 mm Hg in the optimal therapy group. Diastolic BP was significantly lower, by 4.7+/-2.3 mm Hg, in the optimal therapy group (P<.05). Ambulatory BP was also decreased in both groups. There was no significant change in LVM or FMD in either group. Baseline LVM index and FMD values were correlated with systolic BP (r=0.51, P=.02; r=0.54, P=.009). In the optimal therapy group, urinary albumin excretion increased significantly (P=.04). Plasma levels of B-type natriuretic peptide (BNP) decreased with antihypertensive therapy (P=.03). Treatment was well tolerated, and none of the patients withdrew from the study. There was no significant difference in adverse events between the 2 groups. Optimization of BP is feasible, safe, and well tolerated; however, a larger study of longer duration may be needed to demonstrate improvements in LVM and endothelial function with conventional versus optimal therapy.

Regulation of therapeutic apoptosis: a potential target in controlling hypertensive organ damage

Cell growth and survival are potential therapeutic targets for the control of complications associated with hypertension. In most cardiovascular disorders, cardiac fibroblasts and large-vessel smooth muscle cells can replicate and thus contribute to the disease. We propose that cardiovascular hyperplasia may be reversed via therapeutic apoptosis induction with drugs that are safe and already used in the clinic. We first reported that, irrespective of the drug class, those drugs that are able to induce regression of cardiovascular hypertrophy are also able to reverse cardiovascular hyperplasia via apoptosis. Drugs active in this regard include inhibitors of the renin-angiotensin system, calcium channel blockers, and beta-blockers. Moreover, the effects of these drugs on cell survival is not merely secondary to blood pressure reduction. Therapeutic apoptosis in the cardiovascular system of the spontaneously hypertensive rat is characterized by a rapid and transient onset following initiation of antihypertensive treatment. Herein, the induction and termination of therapeutic apoptosis during drug treatment of hypertension will be briefly reviewed and supported by novel data suggesting that reversal of cardiovascular hyperplasia is associated with reduced cell growth and a resistance to further induction of therapeutic apoptosis, as shown in spontaneously hypertensive rats receiving an intermittent regime of nifedipine therapy. We propose that the presence of a cell subpopulation with defective cell cycle regulation may determine organ susceptibility to undergo therapeutic apoptosis.Key words: apoptosis, hypertension, hyperplasia, growth, nifedipine.

Reduction (TELMAR) as assessed by magnetic resonance imaging in patients with mild-to-moderate hypertension--a prospective, randomised, double-blind comparison of telmisartan with metoprolol over a period of six months rationale and study design

The Telmisartan Effectiveness on Left ventricular MAss Reduction (TELMAR) trial will assess the effect of the angiotensin II (Ang II) receptor blocker, telmisartan, on left ventricular hypertrophy (LVH) compared with the b-blocker, metoprolol, at similar antihypertensive doses. The rationale is that antihypertensives reduce LVH, a cardiac adaptation to pressure overload, principally by pressure-related effects. Ang II plays a key role in pressure-independent mechanisms causing LVH, and angiotensin-converting enzyme (ACE) inhibitors induce more pronounced LVH regression than some other antihypertensives. Blocking Ang II Type 1 receptors may be more effective than ACE inhibition in reducing LVH. TELMAR is a prospective, randomised, double-blind, double-dummy, parallel-group trial. A total of 140 patients (age 18 80 years) with uncontrolled essential hypertension (mean daytime systolic blood pressure [SBP] >140 mmHg or diastolic blood pressure [DBP] >90 mmHg and/or night-time SBP >120 mmHg or DBP >70 mmHg, measured by ambulatory blood pressure monitoring [ABPM]) and left ventricular mass index related to height (LVMI) >0.8 g/cm for females, >1.1 g/cm for males (defined by magnetic resonance imaging [MRI]) will be randomised to once-daily telmisartan or metoprolol. The telmisartan dose will be 40 mg for the first two weeks, 80 mg for 5.5 months and 40 mg for the last two weeks. Metoprolol will be given at a dose of 47.5 mg for two weeks, 95 mg for 5.5 months and 47.5 mg for two weeks. Concomitant add-on medication with hydrochlorothiazide and amlodipine will be allowed. The primary endpoint is the percentage change in LVMI at treatment end versus baseline, using MRI. Secondary variables include blood pressure changes and response rates assessed by ABPM and manual cuff sphygmomanometry, and end-systolic wall stress, systolic left ventricular function (LVF) and diastolic LVF determined by MRI. A separate study was performed prior to the main trial to define the normal range of MRI data in an age-matched population.

A central role of EGF receptor transactivation in angiotensin II -induced cardiac hypertrophy

In addition to their physiological roles in the cardiovascular system (CVS), G-protein-coupled receptor (GPCR) agonists such as noradrenaline, endothelin-1 and angiotensin II (Ang II) are known to be involved in the development of cardiac hypertrophy. Recent studies using targeted overexpression of the angiotensin AT(1) receptor in cardiomyocytes suggest that Ang II can directly promote the growth of cardiomyocytes via transactivation of the epidermal growth factor (EGF) receptor and subsequent activation of mitogen-activated protein kinases (MAPKs). This process is mediated by the production of heparin-binding EGF (HB-EGF) by metalloproteases. Blockade of the generation of HB-EGF by metalloprotease inhibitors, or abrogation of EGF receptor kinase activity by selective pharmacological inhibitors or antisense oligonucleotides, protects against Ang II-mediated cardiac hypertrophy. These approaches offer a potential therapeutic strategy to prevent cardiac remodeling and hypertrophy, and possibly prevent progression to heart failure.