Cardiac hypertrophy as a target of antihypertensive therapy

Risk of hypertension and treatment on out-of-hospital cardiac arrest incidence: A case-control study

Hypertension (HTN) is a high risk factor for major cardiovascular adverse events. This study aimed to investigate the effect of HTN risk on out-of-hospital cardiac arrest (OHCA) incidence and determine whether the effect of HTN on OHCA incidence differs according to antihypertensive medication.This case-control study used the Korean Cardiac Arrest Resuscitation Consortium and Korean Community Health Survey (CHS). Cases were defined as emergency medical service-treated adult OHCA patients presumed to have a cardiac etiology from 2015 to 2017. Patients without information on HTN diagnosis were excluded from the study. The Korean CHS database's controls were matched at a 1:2 ratio with strata, including age, gender, and county of residence. Multivariable conditional logistic regression analysis was conducted to estimate HTN risk and antihypertensive treatment on OHCA incidence,A total of 2633 OHCA patients and 5266 community-based controls were enrolled in this study. Among them, 1176 (44.7%) patients and 2049 (38.9%) controls were diagnosed with HTN. HTN was associated with an increased risk of OHCA (adjusted odds ratio [AOR]: 1.19 [1.07-1.32]). On comparing HTN with or without the antihypertensive treatment group with the non-HTN-diagnosed group (as a reference), the HTN without treatment group had the highest AOR (95% confidence interval) (3.41 [2.74-4.24]). The AOR in the HTN treatment group was reduced to that in the non-HTN-diagnosed group (0.96 [0.86-1.08]).HTN increased OHCA risk, and the HTN without treatment group had the highest OHCA risk. Conversely, OHCA risk decreased to the non-HTN-diagnosed group level with HTN treatment.

Protective Effect of Vitis labrusca Leaves Extract on Cardiovascular Dysfunction through HMGB1-TLR4-NFκB Signaling in Spontaneously Hypertensive Rats

The Vitis labrusca is a grapevine that has antioxidant, neuroprotective, hepatoprotective, and anticarcinogenic activity. However, the effect of Vitis labrusca leaves on the cardiovascular system is yet to be ascertained. The present study was designed to investigate the effects of Vitis labrusca leaves extract (HP1) on cardiovascular remodeling in spontaneously hypertensive rats. Experiments were performed in rats and were randomly divided into the following groups: Wistar Kyoto rat (WKY), normal control group; spontaneously hypertensive rats (SHR), negative control group; SHR + Losa, positive control group (losartan, 10 mg/kg/daily, AT₁ receptor blocker) and SHR + HP1 (100 mg/kg/daily). HP1 was orally administered daily for 4 weeks. The HP1 treatment significantly improved blood pressure, electrocardiographic parameters, and echocardiogram parameters compared to hypertensive rats. Additionally, the left ventricular (LV) remodeling and LV dysfunction were significantly improved in HP1-treated hypertensive rats. Furthermore, an increase in fibrotic area has been observed in hypertensive rats compared with WKY. However, administration of HP1 significantly attenuated cardiac fibrosis in hypertensive rats. Moreover, HP1 suppressed the expression of high mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), receptor for advanced glycation end products (RAGE), and extracellular signal-regulated kinases (ERK1/2) induced by hypertensive rats, resulting in improved vascular remodeling. Therefore, these results suggest that HP1 can improve the cardiovascular remodeling in hypertensive rats, and the mechanisms may be related to the suppressive effect of HP1 on HMGB1-TLR4-NFκB signaling in the cardiovascular system. Thus, the protective role of the traditional herbal medicine HP1 may provide new insights into the development of therapeutic drugs on the development of hypertensive cardiovascular dysfunction.

Prevention of Heart Failure in Hypertension-Disentangling the Role of Evolving Left Ventricular Hypertrophy and Blood Pressure Lowering: The ALLHAT Study

Background

Hypertension is a known risk factor for heart failure (HF), possibly via the mechanism of cardiac remodeling and left ventricular hypertrophy (LVH). We studied the extent to which blood pressure (BP) change and evolving LVH contribute to the effect that lisinopril, doxazosin, and amlodipine have on HF compared with chlorthalidone.

Methods and Results

We conducted causal mediation analysis of ALLHAT (Antihypertensive and Lipid‐Lowering Treatment to Prevent Heart Attack Trial) data (1994‐2002; in‐trial follow‐up). ALLHAT participants with available serial ECGs and BP measurements were included (n=29 892; mean age 67±4 years; 32% black; 56% men): 11 008 were randomized to chlorthalidone, 5967 to doxazosin, 6593 to amlodipine, and 6324 to lisinopril. Evolving ECG LVH and BP lowering served as mediators. Incident symptomatic HF was the primary outcome. Linear regression (for mediator) and logistic regression (for outcome) models were adjusted for mediator‐outcome confounders (demographic and clinical characteristics known to be associated both with both LVH/hypertension and HF). A large majority of participants (96%) had ECG LVH status unchanged, but 4% developed evolving ECG LVH. On average, BP decreased by 11/7 mm Hg. In adjusted Cox regression analyses, progressing ECG LVH (hazard ratio [HR] 1.78 [95% CI 1.43‐2.22]), resolving ECG LVH (HR 1.33 [95% CI 1.03‐1.70]), and baseline ECG LVH (1.17 [95% CI 1.04‐1.31]) carried risk of incident HF. After full adjustment, evolving ECG LVH mediated 4% of the effect of doxazosin on HF. Systolic BP lowering mediated 12% of the effect of doxazosin, and diastolic BP lowering mediated 10% of the effect of doxazosin, 7% of the effect of amlodipine, and borderline 9% of the effect of lisinopril on HF.

Conclusions

Evolving ECG LVH and BP change account for 4% to 13% of the mechanism by which antihypertensive medications prevent HF.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000542.

See Editorial Ferdinand and Maraboto

OXY-SCORE: a new perspective for left ventricular hypertrophy diagnosis

Background:

A recently developed global indicator of oxidative stress (OXY-SCORE), by combining individual plasma biomarkers of oxidative damage and antioxidant capacity, has been validated in several pathologies, but not in left ventricular hypertrophy (LVH). The aim of this study was to design and calculate a plasma oxidative stress global index for patients with LVH.

Methods:

A total of 70 consecutive adult patients were recruited in our institution and assigned to one of the two study groups (control group/LVH group) by an echocardiography study. We evaluated plasmatic biomarkers of oxidative damage (malondialdehyde and thiolated proteins) and antioxidant defense (total thiols, reduced glutathione, total antioxidant capacity, catalase, and superoxide dismutase activities) by spectrophotometry/fluorimetry in order to calculate a plasma oxidative stress global index (OXY-SCORE) in relation to LVH.

Results:

The OXY-SCORE exhibited a highly significant difference between the groups (p < 0.001). The area under the receiver operating characteristic curve was 0.74 (95% confidence interval (CI), 0.62–0.85; p < 0.001). At a cut-off value of −1, the 68.6% sensitivity and 68.6% specificity values suggest that OXY-SCORE could be used to screen for LVH. A multivariable logistic regression model showed a positive association (p = 0.001) between OXY-SCORE and LVH [odds ratio = 0.55 (95% CI, 0.39–0.79)], independent of gender, age, smoking, glucose, systolic and diastolic arterial pressure, dyslipidemia, estimated glomerular filtration rate, body mass index, and valvular/coronary disease.

Conclusion:

OXY-SCORE could help in the diagnosis of LVH and could be used to monitor treatment response.

Extract of Plantago asiatica L. Seeds Ameliorates Hypertension in Spontaneously Hypertensive Rats by Inhibition of Angiotensin Converting Enzyme

Plantago asiatica L. seeds is a common folk medicine with a long history of medical use in China because of its antipyretic, diuretic, and expectorant properties. It has been applied to treat hypertension clinically due to its diuresis, however, its efficacy and mechanisms on anti-hypertension has not been reported yet to our knowledge. In this study, we investigated the antihypertensive effect and underlying mechanisms of P. asiatica L. seeds extract (PASE) in spontaneously hypertensive rat (SHR). Male SHRs were treated with 2.5 mg/kg of fosinopril (FOS) and 400 mg/kg of PASE orally per day for once or 12 weeks. SHR or Wistar-Kyoto rats (WKY) receiving vehicle (distilled water) was used as control. The results demonstrated systolic, diastolic, and mean blood pressures (SBP, DBP, and MBP) were significantly lowered after single and long-term intragastric administration of PASE. The cardiac and aortic index and collagen accumulation were improved in the PASE group compared with the SHRs group. Meanwhile, PASE treatment remarkably reduced urine total protein, the ratio of serum urea nitrogen to serum creatinine, and increased serum potassium. The levels of serum angiotensin I (Ang I), angiotensin II (Ang II), the ratio of Ang II to Ang I, and aldosterone (ALD) were lowered after treatment of PASE. Besides, PASE and its major active constituents of phenylethanoid glycosides, including isoacteoside, plantamajoside and acteoside, were found to effectively inhibit angiotensin-converting enzyme (ACE) activation in vitro. These findings suggest that PASE has the antihypertensive effect that may involve a mechanism of ACE inhibition and simultaneously protect organ damage against hypertension.

Targeting Pim Kinases and DAPK3 to Control Hypertension

Sustained vascular smooth muscle hypercontractility promotes hypertension and cardiovascular disease. The etiology of hypercontractility is not completely understood. New therapeutic targets remain vitally important for drug discovery. Here we report that Pim kinases, in combination with DAPK3, regulate contractility and control hypertension. Using a co-crystal structure of lead molecule (HS38) in complex with DAPK3, a dual Pim/DAPK3 inhibitor (HS56) and selective DAPK3 inhibitors (HS94 and HS148) were developed to provide mechanistic insight into the polypharmacology of hypertension. In vitro and ex vivo studies indicated that Pim kinases directly phosphorylate smooth muscle targets and that Pim/DAPK3 inhibition, unlike selective DAPK3 inhibition, significantly reduces contractility. In vivo, HS56 decreased blood pressure in spontaneously hypertensive mice in a dose-dependent manner without affecting heart rate. These findings suggest including Pim kinase inhibition within a multi-target engagement strategy for hypertension management. HS56 represents a significant step in the development of molecularly targeted antihypertensive medications.

Risk stratification of sudden cardiac death in hypertension

In the United States, up to 450,000 people per year die suddenly; an average of 1 sudden death every 70s. Strategies for preventing sudden cardiac death are urgently needed. Systemic arterial hypertension is a major risk factor for sudden cardiac death and the increasing burden of hypertension is a worldwide problem. The lifetime risk of sudden cardiac death at 30years of age is higher by 30% in individuals with hypertension. Each 20/10mmHg increase in systolic/diastolic blood pressure, is associated with a 20% additional increase in sudden cardiac death risk. Theoretically, antihypertensive treatment should be an effective strategy for sudden cardiac death prevention. However, a recent meta-analysis of 15 randomized controlled trials showed that antihypertensive treatment does not reduce the incidence of sudden cardiac death. This manuscript reviews ECG predictors of sudden cardiac death and the importance of risk stratification for appropriate management of hypertension.

Lactacystin-Induced Model of Hypertension in Rats: Effects of Melatonin and Captopril

Lactacystin is a proteasome inhibitor that interferes with several factors involved in heart remodelling. The aim of this study was to investigate whether the chronic administration of lactacystin induces hypertension and heart remodelling and whether these changes can be modified by captopril or melatonin. In addition, the lactacystin-model was compared with NG-nitro-l-arginine-methyl ester (L-NAME)- and continuous light-induced hypertension. Six groups of three-month-old male Wistar rats (11 per group) were treated for six weeks as follows: control (vehicle), L-NAME (40 mg/kg/day), continuous light (24 h/day), lactacystin (5 mg/kg/day) alone, and lactacystin with captopril (100 mg/kg/day), or melatonin (10 mg/kg/day). Lactacystin treatment increased systolic blood pressure (SBP) and induced fibrosis of the left ventricle (LV), as observed in L-NAME-hypertension and continuous light-hypertension. LV weight and the cross-sectional area of the aorta were increased only in L-NAME-induced hypertension. The level of oxidative load was preserved or reduced in all three models of hypertension. Nitric oxide synthase (NOS) activity in the LV and kidney was unchanged in the lactacystin group. Nuclear factor-kappa B (NF-κB) protein expression in the LV was increased in all treated groups in the cytoplasm, however, in neither group in the nucleus. Although melatonin had no effect on SBP, only this indolamine (but not captopril) reduced the concentration of insoluble and total collagen in the LV and stimulated the NO-pathway in the lactacystin group. We conclude that chronic administration of lactacystin represents a novel model of hypertension with collagenous rebuilding of the LV, convenient for testing antihypertensive drugs or agents exerting a cardiovascular benefit beyond blood pressure reduction.

Antihypertensive treatment is not a risk factor for major cardiovascular events in the Gubbio residential cohort study

BACKGROUND AND OBJECTIVES

Demonstration of antihypertensive beneficial role in population settings is difficult. Relationships of antihypertensive treatment, blood pressure control, risk factors and cardiovascular outcomes were investigated in the Gubbio study.

MATERIAL AND METHODS

Among 2248 cardiovascular disease-free men and women aged 35-74 years, individuals were classified as nonhypertensive, controlled hypertensive, uncontrolled hypertensive and untreated hypertensive based on cut-off limits of 140/90  mmHg for SBP/DBP and/or the use of antihypertensive drugs. End-point was the first major coronary, cerebrovascular or peripheral hard event [cardiovascular disease (CVD)] during a 15-year average. Univariate and multivariate analyses were run.

RESULTS

Nonhypertensive individuals were about 10 years younger and had lower risk factor levels than the other categories. The relative risk (and 95% confidence interval) for CVD versus nonhypertension was 1.78 (1.02-3.10) for controlled hypertension, 3.76 (2.79-5.06) for uncontrolled hypertension and 3.30 (2.59-4.21) for untreated hypertension (UTH). After adjusting for covariates, such as sex, age, achieved blood pressure and other risk factors, the CVD risk of controlled hypertension was practically equal to that of nonhypertension, and remained unchanged even when blood pressure was excluded from the model (1.03, 0.58-1.82). The higher cardiovascular risk of uncontrolled hypertension and UTH was reduced after adjusting for covariates, but remained significantly higher than in nonhypertension, with no significant differences between uncontrolled hypertension and UTH.

CONCLUSIONS

A higher level of baseline risk is not due to treatment per se, the risk being similar in uncontrolled hypertension and UTH. Adjustment for risk factors reduces the risk only in controlled hypertension, suggesting that there may be structural alterations scarcely reversible by antihypertensive treatment.

Effects of blood pressure-lowering on outcome incidence in hypertension: 5. Head-to-head comparisons of various classes of antihypertensive drugs - overview and meta-analyses

BACKGROUND AND OBJECTIVES

We have recently published an overview and meta-analysis of the effects of the five major classes of blood pressure-lowering drugs on cardiovascular outcomes when compared with placebo. However, possible differences in effectiveness of the various classes can correctly be estimated only by head-to-head comparisons of different classes of agents. This has been the objective of a new survey and meta-analysis.

METHODS

A database search between 1966 and August 2014 ide ntified 50 eligible randomized controlled trials for 58 two-drug comparisons (247 006 patients for 1 029 768 patient-years). Risk ratios and their 95% confidence intervals of seven outcomes were estimated by a random-effects model.

RESULTS

The effects of all drug classes are not significantly different on most outcomes when their blood pressure effect is equivalent. However, there are also significant differences involving almost all classes of drugs. When compared to all other classes together, diuretics are superior in preventing heart failure; beta-blockers less effective in preventing stroke; calcium antagonists superior in preventing stroke and all-cause death, but inferior in preventing heart failure; angiotensin-converting enzyme inhibitors more effective in preventing coronary heart disease and less in preventing stroke; angiotensin receptor blockers inferior in preventing coronary heart disease; and renin-angiotensin system blockers more effective in preventing heart failure. When stratifying randomized controlled trials according to total cardiovascular risk, no drug class was found to change in effectiveness with the level of risk.

CONCLUSIONS

The results of all available evidence from head-to-head drug class comparisons do not allow the formulation of a fixed paradigm of drug choice valuable for all hypertensive patients, but the differences found may suggest specific choices in specific conditions, or preferable combinations of drugs.

Does the ADMA/DDAH/NO pathway modulate early regression of left ventricular hypertrophy with esmolol?

Hypertensive left ventricular hypertrophy (LVH) is a maladaptive response to chronic pressure overload and a strong independent risk factor for cardiovascular disease. Regression of LVH is associated with improved prognosis. Regression of LVH with antihypertensive therapy (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, calcium channel blockers, and diuretics) has been reported, although only after long-term treatment. Asymmetrical dimethylarginine (ADMA), the most potent endogenous NO synthase inhibitor, is emerging as an important cardiovascular risk factor in patients with arterial hypertension and LVH, and dimethylarginine dimethylaminohydrolase (DDAH) is the mechanism that most frequently leads to accumulation of ADMA (plasma ADMA is cleared in small part by renal excretion, although the bulk of ADMA is degraded by DDAH). Left ventricular mass is strongly modulated by the NO system. As an important inhibitor of the bioavailability of NO, ADMA is an underlying mechanism of LVH. Beta-blockers can induce regression of LVH and reduced plasma ADMA levels. Oxidative stress is increased in patients with LVH, and this in turn increases generation of ADMA. In a previous preclinical study of spontaneously hypertensive rats, we found that short-term treatment (48 h) with esmolol reverses early LVH, increases the bioavailability of NO, and improves antioxidant status in plasma. Therefore, we propose that the ADMA/DDAH/NO pathway could modulate early regression of LVH with esmolol.

Isosorbide dinitrate inhibits mechanical stress-induced cardiac hypertrophy and autophagy through downregulation of angiotensin II type 1 receptor

Mechanical stress can induce cardiac hypertrophy and autophagy. Recently, it has been reported that nitric oxide donors inhibited autophagy in human chondrocytes. Therefore, the effect of isosorbide dinitrate (ISDN) on cardiac hypertrophy and autophagy induced by mechanical stress was investigated in this study. A 48-hour mechanical stretch and a 4-week transverse aortic constriction were performed to induce cardiomyocyte hypertrophy in vitro and in vivo, respectively, before the assessment of myocardial autophagy using LC3b-II. ISDN was found to significantly reduce mechanical stretch-induced LC3b-II upregulation. Furthermore, mechanical stress was shown to upregulate angiotensin II (AngII) type 1 (AT1) receptor expression in both cultured cardiomyocytes and in mouse hearts, whereas ISDN was demonstrated to significantly suppress the upregulation of the AT1 receptor. It was concluded that ISDN could inhibit mechanical stress-induced cardiac hypertrophy and autophagy through the downregulation of AT1 receptor expression.

Mechanical stress triggers cardiomyocyte autophagy through angiotensin II type 1 receptor-mediated p38MAP kinase independently of angiotensin II

Angiotensin II (Ang II) type 1 (AT1) receptor is known to mediate a variety of physiological actions of Ang II including autophagy. However, the role of AT1 receptor in cardiomyocyte autophagy triggered by mechanical stress still remains elusive. The aim of this study was therefore to examine whether and how AT1 receptor participates in cardiomyocyte autophagy induced by mechanical stresses. A 48-hour mechanical stretch and a 4-week transverse aorta constriction (TAC) were imposed to cultured cardiomyocytes of neonatal rats and adult male C57B/L6 mice, respectively, to induce cardiomyocyte hypertrophy prior to the assessment of cardiomyocyte autophagy using LC3b-II. Losartan, an AT1 receptor blocker, but not PD123319, the AT2 inhibitor, was found to significantly reduce mechanical stretch-induced LC3b-II upregulation. Moreover, inhibition of p38MAP kinase attenuated not only mechanical stretch-induced cardiomyocyte hypertrophy but also autophagy. To the contrary, inhibition of ERK and JNK suppressed cardiac hypertrophy but not autophagy. Intriguingly, mechanical stretch-induced autophagy was significantly inhibited by Losartan in the absence of Ang II. Taken together, our results indicate that mechanical stress triggers cardiomyocyte autophagy through AT1 receptor-mediated activation of p38MAP kinase independently of Ang II.

Remodelling of the heart and vessels in experimental hypertension: advances in protection

Left ventricular hypertrophy (LVH), despite its adaptive nature, increases cardiovascular morbidity and mortality. Novel approaches for protection against pathological heart remodelling are presented in this supplement. Melatonin diminishes myocardial fibrosis in rats exposed to continuous light and N-nitro-L-arginine-methyl ester (L-NAME) treatment and reduces production of endothelium-derived constricting factors in L-NAME-induced hypertension. Melatonin, because of its extraordinary antioxidant and scavenging properties, benefits for endothelium and sympatholytic action, may prove to be a useful protective drug against heart remodelling. In hypertension induced by relative aldosteronism, the correction of macro and micronutrient dyshomeostasis appears to act beneficially within pathological myocardial remodelling. Alterations in the signal cascade of pathological myocardial growth, including humoral stimuli, receptors, intracellular messengers or transcriptional factors, may be favourably modified at different levels. Inhibition of nuclear factor kappa B (NF-kappaB) potentiates hypertension development, enhances oxidative load, increases the cross-sectional area of the aorta and reduces nitric oxide (NO) synthase activity in L-NAME hypertension. It is suggested that NF-kappaB may play a protective rather than a deleterious role in the haemodynamically overloaded circulation. Compound 21, a recently developed peptide angiotensin II type 2 (AT2) receptor agonist, offers a novel approach in investigating the role of AT2 receptors in the protection of the hypertensive heart. A novel NO donor, L-419, with its intrinsic protection of NO, improves the entire NO signalling cascade and thus favourably influencing the response of the left ventricle to haemodynamic overload. LVH prevention or regression should be considered a therapeutic success only when, along with hypertrophied mass reduction, an improvement of the heart structure, function, metabolism and electrical stability is achieved.