Effect of dual blockade of renin–angiotensin system on TGFβ1 and left ventricular structure and function in hypertensive patients

Differential Role of Aldosterone and Transforming Growth Factor Beta-1 in Cardiac Remodeling

Angiotensin II, a major culprit in cardiovascular disease, activates mediators that are also involved in pathological cardiac remodeling. In this context, we aimed at investigating the effects of two of them: aldosterone (Ald) and transforming growth factor beta-1 (TGF-β1) in an in vivo model. Six-week-old male wild-type (WT) and TGF-β1-overexpressing transgenic (TGF-β1-TG) mice were infused with subhypertensive doses of Ald for 2 weeks and/or treated orally with eplerenone from postnatal day 21. Thehearts' ventricles were examined by morphometry, immunoblotting to assess the intracellular signaling pathways and RT qPCR to determine hypertrophy and fibrosis marker genes. The TGF-β1-TG mice spontaneously developed cardiac hypertrophy and interstitial fibrosis and exhibited a higher baseline phosphorylation of p44/42 and p38 kinases, fibronectin and ANP mRNA expression. Ald induced a comparable increase in the ventricular-heart-weight-to-body-weight ratio and cardiomyocyte diameter in both strains, but a less pronounced increase in interstitial fibrosis in the transgenic compared to the WT mice (23.6% vs. 80.9%, p < 0.005). Ald increased the phosphorylation of p44/42 and p38 in the WT but not the TGF-β1-TG mice. While the eplerenone-enriched chow partially prevented Ald-induced cardiac hypertrophy in both genotypes and interstitial fibrosis in the WT controls, it completely protected against additional fibrosis in transgenic mice. Ald appears to induce cardiac hypertrophy independently of TGF-β1, while in the case of fibrosis, the downstream signaling pathways of these two factors probably converge.

Comparative efficacy of different types of antihypertensive drugs in reversing left ventricular hypertrophy as determined with echocardiography in hypertensive patients: A network meta-analysis of randomized controlled trials

Reversing left ventricular hypertrophy (LVH) can reduce the incidence of adverse cardiovascular events. However, there is no clear superiority-inferiority differentiation between angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), beta-blockers (BB), calcium channel blockers (CCB), and diuretics in reversing LVH in hypertensive patients. To provide further evidence for choosing the optimal antihypertensive drug for improving LVH, we performed a network meta-analysis of randomized controlled trials (RCTs) based on the Cochrane library database, Embase, and Pubmed, and identified 49 studies involving 5402 patients that were eligible for inclusion. It was found that ARB could improve LVH in hypertensive patients more effectively than CCB (MD -4.07, 95%CI -8.03 to -0.24) and BB (MD -4.57, 95%CI -8.07 to -1.12). Matched comparison of renin-angiotensin system inhibitors (RASi) showed that the effect of ACEI in reducing left ventricular mass index (LVMi) was not effective as that of ARB (MD -3.72, 95%CI -7.52 to -0.11). The surface under the cumulative ranking for each intervention indicated that the use of ARB was more effective among the different types of antihypertensive drugs (97%). This network meta-analysis revealed that the use of ARB in antihypertensive therapy could achieve better efficacy in reversing LVH in hypertensive patients.

A systematic review and network meta-analysis of the comparative efficacy of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in hypertension

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are drugs commonly used for the treatment of hypertension. However, studies on their comparative efficacy have not been extensively investigated. The current systematic review and network meta-analysis studied the comparative efficacy of the two antihypertensive treatment categories in reducing blood pressure, mortality, and morbidity in essential hypertension patients. A literature search was carried out in Medline and Cochrane Central Register of Controlled Trials for placebo- and active-controlled, double-blind randomized clinical trials, which had reported blood pressure effects, mortality, and/or morbidity. Blood pressure results were found in 30 studies with 7370 participants and 8 studies with 25,158 participants with mortality/morbidity results included in the analysis. The two drug classes had similar effectiveness in lowering systolic (weighted mean difference (WMD): 0.59, 95% CI: -0.21 to 1.38) and diastolic blood pressure (WMD: 0.62, 95% CI: -0.06 to 1.30), all-cause mortality (risk ratio (RR)): 0.96, 95% CI 0.80 to 1.14), cardiovascular mortality (RR: 0.87, 95% CI 0.67 to 1.14), fatal and non-fatal myocardial infarction (RR: 1.02, 95% CI 0.75 to 1.37) and stroke (RR: 1.13, 95% CI 0.87 to 1.46). Angiotensin-converting enzyme inhibitors were more helpful in the prevention and/or the hospitalization for heart failure than angiotensin receptor blockers (RR: 0.71, 95% CI 0.54 to 0.93). Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers were similarly effective in decreasing blood pressure, mortality, and morbidity in essential hypertension. Angiotensin-converting enzyme inhibitors were more protective in the advancement and/or hospitalization of the hypertensive patient for heart failure than angiotensin receptor blockers.

Emerging drugs for chronic kidney disease

INTRODUCTION

Chronic kidney disease (CKD) is a worldwide health problem. Despite remarkable headway in slowing the progression of kidney diseases, the incidence of end-stage renal disease (ESRD) is increasing in all countries with a severe impact on patients and society. The high incidence of diabetes and hypertension, along with the aging population, may partially explain this growth. Currently, the mainstay of pharmacological treatment for CKD, aiming to slow progression to ESRD are ACE inhibitors and angiotensin II receptor blockers for their hemodynamic/antihypertensive and anti-inflammatory/antifibrotic action. However, novel drugs would be highly desirable to effectively slow the progressive renal function loss.

AREAS COVERED

Through the search engines, PubMed and ClinicalTrial.gov, the scientific literature was reviewed in search of emerging drugs in Phase II or III trials, which appear to be the most promising for CKD treatment.

EXPERT OPINION

The great expectations for new drugs for the management of CKD over the last decade have unfortunately not been met. Encouraging results from preliminary studies with specific agents need to be tempered with caution, given the absence of consistent and adequate data. To date, several agents that showed great promise in animal studies have been less effective in humans.

Effect of oxymatrine, the active component from Radix Sophorae flavescentis (Kushen), on ventricular remodeling in spontaneously hypertensive rats

PURPOSE

To examine the effects of oxymatrine (OMT) on ventricular remodeling in spontaneous hypertension rat (SHR) and the underlying mechanism.

METHODS

SHRs were divided into four groups: SHR control, SHR+40 mg/kg captopril, SHR+30 mg/kg OMT and SHR+60 mg/kg OMT. Normotensive age-matched WKY rats were assigned to two groups: WKY control, WKY+30 mg/kg OMT. The rats were orally administered with the corresponding drugs or drinking water for 21 weeks. Mean arterial blood pressure (MAP) and heart rate (HR) were measured. The left ventricular weight index (LVWI) and heart weight index (HWI) were determined. Myocardium tissue was stained with picric acid/Sirius red for measurement of collagen content measurements. The concentrations of serum norepinephrine and angiotensin II (Ang II) in myocardium were determined. Real-time RT-PCR was used to detect the mRNA expressions of transforming growth factor-β1 (TGF-β1), collagen types I, III and angiotensin converting enzyme (ACE). Western blots were performed to determine bioactivities of extracellular signal regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK/SAPK), p38 mitogen-activated protein kinases (p38 MAPK) and phospho-specific protein kinase C (PKC).

RESULTS

In the SHR, hypertension, myocardium hypertrophy, more cardiac fibrosis, higher concentrations of serum norepinephrine and myocardium Ang II were observed. OMT treatment lowered the blood pressure, reduced the concentrations of serum norepinephrine and myocardium Ang II, favorably decreased the measured gravimetric parameters, decreased the interstitial and perivascular collagen deposition, attenuated the collagen of type I and III accumulation, downregulated the mRNA expression of ACE and TGF-β1, and suppressed the phosphorylation of ERK 1/2, JNK and p38 MAPK in SHRs.

CONCLUSION

OMT prevents ventricular remodeling in SHR. The mechanisms may be related to inhibiting the gene overexpression of ACE and TGF-β1, suppressing the activation of signaling pathways of ERK 1/2, JNK and p38 MAPK.

Updated report on comparative effectiveness of ACE inhibitors, ARBs, and direct renin inhibitors for patients with essential hypertension: much more data, little new information

OBJECTIVES

A 2007 systematic review compared angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) in patients with hypertension. Direct renin inhibitors (DRIs) have since been introduced, and significant new research has been published. We sought to update and expand the 2007 review.

DATA SOURCES

We searched MEDLINE and EMBASE (through December 2010) and selected other sources for relevant English-language trials.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

We included studies that directly compared ACE inhibitors, ARBs, and/or DRIs in at least 20 total adults with essential hypertension; had at least 12 weeks of follow-up; and reported at least one outcome of interest. Ninety-seven (97) studies (36 new since 2007) directly comparing ACE inhibitors versus ARBs and three studies directly comparing DRIs to ACE inhibitor inhibitors or ARBs were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

A standard protocol was used to extract data on study design, interventions, population characteristics, and outcomes; evaluate study quality; and summarize the evidence.

RESULTS

In spite of substantial new evidence, none of the conclusions from the 2007 review changed. The level of evidence remains high for equivalence between ACE inhibitors and ARBs for blood pressure lowering and use as single antihypertensive agents, as well as for superiority of ARBs for short-term adverse events (primarily cough). However, the new evidence was insufficient on long-term cardiovascular outcomes, quality of life, progression of renal disease, medication adherence or persistence, rates of angioedema, and differences in key patient subgroups.

LIMITATIONS

Included studies were limited by follow-up duration, protocol heterogeneity, and infrequent reporting on patient subgroups.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Evidence does not support a meaningful difference between ACE inhibitors and ARBs for any outcome except medication side effects. Few, if any, of the questions that were not answered in the 2007 report have been addressed by the 36 new studies. Future research in this area should consider areas of uncertainty and be prioritized accordingly.

The effect of amlodipine besylate, losartan potassium, olmesartan medoxomil, and other antihypertensives on central aortic blood pressure and biomarkers of vascular function

Biomarkers are being increasingly used in the study of cardiovascular disease because they provide readily quantifiable surrogate endpoints and allow accurate assessment of the effects of therapy on particular pathological processes. However, in order to be useful, biomarkers must be relevant, predictable, accurate, and reproducible. There is compelling evidence from large-scale clinical trials that inhibitors of the renin-angiotensin system [angiotensin-converting enzyme inhibitors and angiotensin type II receptor blockers (ARBs)] and calcium channel blockers (CCBs) may have beneficial effects beyond blood pressure control in the treatment of hypertension. Biomarkers are expected to provide further insight into these beneficial effects and allow for quantitative assessment. This review summarizes the published clinical evidence on the effects of various antihypertensive drugs, particularly ARBs (e.g. losartan and olmesartan medoxomil) and CCBs (e.g. amlodipine), alone and in combination with other agents (e.g. hydrochlorothiazide), on central aortic pressure and the biomarkers high-sensitivity C-reactive protein (hsCRP), adiponectin, cystatin C, homeostasis model assessment of insulin resistance (HOMA-IR), procollagen, tumor necrosis factor-α, and interleukin-6. Of these biomarkers, the benefits of antihypertensive therapy on hsCRP, adiponectin, and HOMA-IR reflect a potential for quantifiable long-term vascular benefits.

ACE inhibitors - angiotensin II receptor antagonists: A useful combination therapy for ischemic heart disease

Morbidity and mortality from cardiovascular diseases are still high, even with the use of the best available therapies. There is mounting evidence that excessive renin-angiotensin system activation triggers much of the damaging and progressive nature of cardiovascular and kidney diseases through expression of angiotensin II. Moreover, angiotensin II play a major role in the development of end organ damage through a variety of inflammatory mechanisms. Today, angiotensins-converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists have clearly demonstrated their efficacy in preventing target organ damage and in reducing cardiovascular morbidity and mortality in ischemic heart disease (IHD). Moreover, the development of angiotensin II receptor antagonists has enabled a large gain in tolerability and safety. Several clinical trials have firmly established that these drugs act on the renin–angiotensin system, reducing the incidence of coronary events with monotherapy and combination therapy. In this review we summarize the role mono- and combined therapy of ACE inhibitors and angiotensin II receptor antagonists play in ischemic heart disease. In this respect the review will improve ideas for developing new formulations with combinations of these drugs in the future.

Dual blockade of the renin-angiotensin-aldosterone system in cardiac and renal disease

PURPOSE OF REVIEW

Renin-angiotensin-aldosterone system (RAAS) blockade improves outcome in cardiovascular disease (CVD) and chronic kidney disease (CKD), but the residual risk during monotherapy RAAS blockade remains very high. This review discusses the place of dual RAAS blockade in improving these outcomes.

RECENT FINDINGS

The combination of angiotensin-converting enzyme inhibitor (ACEI) with angiotensin II type 1 receptor blocker (ARB) generally had a better antihypertensive and antiproteinuric effect than monotherapy in many studies, but is also associated with more adverse effects. Unfortunately, the effect on hard renal and cardiovascular endpoints is not unequivocal. The combination of ACEI (or ARB) with aldosterone blockade has long-term benefits in heart failure, and an added effect on proteinuria in CKD, but data on hard renal endpoints are lacking. Dual blockade including renin inhibition has added antiproteinuric effects, but studies to gather long-term data are still under way. Available strategies to optimize the effect of monotherapy RAAS blockade include dose titration and correction of volume excess. Whether dual blockade has better efficacy and/or fewer adverse effects than optimized monotherapy has not been investigated.

SUMMARY

Several options are available to increase the effect of monotherapy RAAS blockade. For proteinuric CKD, these can be combined in a stepwise approach aimed at maximal proteinuria reduction; this includes dual blockade for patients with persistent proteinuria during optimized monotherapy RAAS blockade. Long-term randomized studies, however, are needed to support the benefits of dual blockade for long-term renal and cardiovascular outcome in CKD.

The Relationship between the Transforming Growth Factor β1 T29C Gene Polymorphism and Left Ventricular Geometry and Function in Hypertensive Subjects

The distribution of the T29C TGFβ1 gene polymorphism was analyzed in 198 hypertensives with left ventricular hypertrophy (LVH) and in 235 hypertensives without LVH. Circulating TGFβ1 levels, procollagen type III levels, microalbuminuria, and left ventricular geometry and function were evaluated in all the hypertensives with LVH subgrouped according to T29C TGFβ1 gene polymorphism. Circulating TGFβ1 was evaluated by ELISA technique, procollagen type III by a specific radioimmunoassay, microalbuminuria by radioimmunoassay, and left ventricular geometry and function by echocardiography. All groups were comparable for gender, age, and sex. Regarding T29C TGFβ1 gene polymorphism, prevalence of TC or CC genotypes was significantly (P < .05) higher in hypertensives with LVH than hypertensives without LVH TC and CC LVH hypertensives were characterized by a higher prevalence of subjects with microalbuminuria (P < .05 TC and CC versus TT), by increased levels of TGFβ1, procollagen type III, urinary albumin excretion, LVM, LVM/h_2.7, and lower values of left ventricular ejection fraction (P < .05 TC and CC versus TT). Our data suggest that T29C TGFβ1 gene polymorphism was associated with clinical characteristics adequate to recognize a subset of LVH hypertensives with a higher severity of hypertension.

Effects of Telmisartan, Ramipril, and Their Combination on Left Ventricular Hypertrophy in Individuals at High Vascular Risk in the Ongoing Telmisartan Alone and in Combination With Ramipril Global End Point Trial and the Telmisartan Randomized Assessment Study in ACE Intolerant Subjects With Cardiovascular Disease

Background— Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers reduce left ventricular hypertrophy (LVH). The effect of these drugs on LVH in high-risk patients without heart failure is unknown.

Methods and Results— In the Ongoing Telmisartan Alone and in Combination With Ramipril Global End Point Trial (ONTARGET), patients at high vascular risk and tolerant of ACE inhibitors were randomly assigned to ramipril, telmisartan, or their combination (n=23 165). In the Telmisartan Randomized Assessment Study in ACE Intolerant Subjects With Cardiovascular Disease (TRANSCEND), patients intolerant of ACE inhibitors were randomized to telmisartan or placebo (n=5343). Prevalence of LVH at entry in TRANSCEND was 12.7%. It was reduced by telmisartan (10.5% and 9.9% after 2 and 5 years) compared with placebo (12.7% and 12.8% after 2 and 5 years) (overall odds ratio, 0.79; 95% confidence interval [CI], 0.68 to 0.91; P =0.0017). New-onset LVH occurred less frequently with telmisartan compared with placebo (overall odds ratio, 0.63; 95% CI, 0.51 to 0.79; P =0.0001). LVH regression was similar in the 2 groups. In ONTARGET, prevalence of LVH at entry was 12.4%. At follow-up, it occurred slightly less frequently with telmisartan (odds ratio, 0.92; 95% CI, 0.83 to 1.01; P =0.07) and the combination (odds ratio, 0.93; 95% CI, 0.84 to 1.02; P =0.12) than with ramipril, but differences between the groups were not significant. New-onset LVH was associated with a higher risk of primary outcome during follow-up (hazard ratio, 1.77; 95% CI, 1.50 to 2.07).

Conclusions— In patients at high vascular risk, telmisartan is more effective than placebo in reducing LVH. New-onset LVH is reduced by 37%. The effect of combination of the 2 drugs on LVH is similar to that of ramipril alone.

Transforming growth factor beta1 T29C gene polymorphism and hypertension: relationship with cardiovascular and renal damage

Distribution of T29C TGFbeta1 gene polymorphism was analysed in 260 hypertensive and 134 normotensive subjects. Circulating TGFbeta1 and procollagen type III levels, microalbuminuria, left ventricular geometry and function were evaluated in all the hypertensives subgrouped according to T29C TGFbeta1 gene polymorphism. Circulating TGFbeta1 by ELISA technique, procollagen type III by a specific radioimmunoassay, microalbuminuria by radioimmunoassay, left ventricular geometry and function by echocardiography were determined. All groups were comparable for gender, age and sex. Regarding T29C TGFbeta1 gene polymorphism, prevalence of TC or CC genotypes was significantly (p<0.05) higher in hypertensives than normotensives. TC and CC hypertensives were characterized by a higher prevalence of subjects with microalbuminuria (p<0.001 TC vs TT; p<0.05 CC vs TT), left ventricular hypertrophy (p<0.01 TC and CC vs TT), and by increased levels of procollagen type III (p<0.05 TC and CC vs TT). TC hypertensives were also characterized by a significant increase (p<0.05) of LVM and LVM/h(2.7 )and of urinary albumin excretion (p<0.05) values than those detectable in TT hypertensives. Our data suggest that T29C TGFbeta1 gene polymorphism was associated to clinical characteristics suitable to recognize hypertensives with a higher severity of hypertension.

Evaluation of recent fixed-dose combination therapies in the management of hypertension

PURPOSE OF REVIEW

Control of hypertension remains sub-optimal with only half of patients achieving adequate control. The Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure guidelines recommend initial use of two antihypertensive agents in patients with stage 2 hypertension. This review discusses the drug combinations that have additive effects and those that do not provide additional benefit while increasing the adverse events.

RECENT FINDINGS

Results from late-breaking trials have shown that combinations of a calcium channel blocker and angiotensin-converting enzyme inhibitor are superior to a diuretic with an angiotensin-converting enzyme inhibitor for reducing cardiovascular events. Additionally, in patients with vascular disease with relatively 'controlled' blood pressure at baseline, the combination of an angiotensin-converting enzyme inhibitor and angiotensin receptor blocker did not reduce cardiovascular endpoints compared with either monotherapy and modestly increased the incidence of adverse effects.

SUMMARY

Combination therapy of antihypertensive agents (e.g. angiotensin-converting enzyme inhibitor/calcium channel blocker, angiotensin-converting enzyme inhibitor/diuretics, and angiotensin receptor blocker/diuretics) as initial therapy in stage 2 hypertension can lead to markedly improved blood pressure control in patients compared with monotherapeutic regimens.

A synthetic peptide from transforming growth factor-beta1 type III receptor prevents myocardial fibrosis in spontaneously hypertensive rats

AIM

We investigated whether P144, a synthetic peptide from transforming growth factor-beta(1) (TGF-beta(1)) type III receptor betaglycan, exhibits cardiac antifibrotic properties.

METHODS AND RESULTS

The study was carried out in one group of 10-week-old normotensive Wistar-Kyoto rats treated with vehicle (V-WKY), one group of 10-week-old spontaneously hypertensive rats treated with vehicle (V-SHR), and one group of 10-week-old SHR treated with P144 (P144-SHR) for 12 weeks. Two more groups of 10-week-old untreated WKY and SHR were used to assess baseline values of the parameters tested. In addition, the effects of P144 on rat cardiac fibroblasts stimulated with TGF-beta(1) were also studied. Compared with V-WKY, V-SHR exhibited significant increases in the myocardial expression of phosphorylated Smad2, 38 and 42 kDa connective tissue growth factor (CTGF) isoforms, procollagen alpha1 (I) mRNA, and collagen type I protein, as well as in the expression of lysyl oxidase (LOX) mRNA and protein, collagen cross-linking and deposition. P144 administration was associated with significant reduction in all these parameters in P144-SHR. TGF-beta(1)-stimulated fibroblasts exhibited significant increases in phosphorylated Smad2, 38 and 42 kDa CTGF proteins, and procollagen alpha(1) (I) mRNA compared with control fibroblasts. No significant differences were found in these parameters between fibroblasts incubated with TGF-beta(1) and P144 and control fibroblasts.

CONCLUSION

These results show that P144 inhibits TGF-beta(1)-dependent signalling pathway and collagen type I synthesis in cardiac fibroblasts. These effects may be involved in the ability of this peptide to prevent myocardial fibrosis in SHR.

Review: The therapeutic role of RAS blockade in chronic heart failure

Cardiovascular disease represents a continuum that starts with risk factors such as hypertension and progresses to atherosclerosis, end-organ damage, and ultimately to chronic heart failure (CHF) and premature death. Renin-angiotensin system (RAS) blockade with angiotensin converting enzyme (ACE) inhibitors and/or angiotensin II type 1 receptor blockers (ARBs) has turned out to be beneficial at all stages of this continuum. Several mechanisms govern the progression of structural myocardial damage to end-stage CHF. Chronic neuroendocrine activation fosters left ventricular remodeling and dilatation and leads to clinical symptoms of CHF via forward/backward failure. RAS inhibition is a cornerstone of neuroendocrine blockade in CHF patients, and combined RAS blockade is especially effective in patients presenting with repetitive cardiac decompensations. This review focuses on the therapeutic role of inhibitors of different RAS components in chronic heart failure caused by systolic left ventricular dysfunction.