Nebivolol improves diastolic dysfunction and myocardial remodeling through reductions in oxidative stress in the transgenic (mRen2) rat

Regulatory effects of curcumin on nitric oxide signaling in the cardiovascular system

The continuously rising prevalence of cardiovascular disease (CVD) globally substantially impacts the economic growth of developing countries. Indeed, one of the leading causes of death worldwide is unfavorable cardiovascular events. Reduced nitric oxide (NO) generation is the pathogenic foundation of endothelial dysfunction, which is regarded as the first stage in the development of a number of CVDs. Nitric oxide exerts an array of biological effects, including vasodilation, the suppression of vascular smooth muscle cell proliferation and the functional control of cardiac cells. Numerous treatment strategies aim to increase NO synthesis or upregulate downstream NO signaling pathways. The major component of Curcuma longa, curcumin, has long been utilized in traditional medicine to treat various illnesses, especially CVDs. Curcumin improves CV function as well as having important pleiotropic effects, such as anti-inflammatory and antioxidant, through its ability to increase the bioavailability of NO and to positively impact NO-related signaling pathways. In this review, we discuss the scientific literature relating to curcumin's positive effects on NO signaling and vascular endothelial function.

Comparison of the Protective Effects of Nebivolol and Metoprolol against LPS-Induced Injury in H9c2 Cardiomyoblasts

Here, we, for the first time, compared the cardioprotective effects of third-generation vasodilating beta-blocker nebivolol (Neb) and conventional beta-blocker metoprolol (Met) on LPS-induced injury in H9c2 cardiomyoblasts. Our findings denoted that Neb and Met pretreatment diminish LPS-mediated cytotoxicity and oxidative stress. Concomitantly, LPS-triggered inflammatory cytokines activation was significantly suppressed by Neb but not by Met. Pretreatment with either Neb or Met alleviated LPS-mediated mitochondrial impairment by enhancing the expression of genes related to its biogenesis such as PGC-1α, NRF1, and TFAM. On the contrary, Neb but not Met-upregulated mitochondrial fusion-related genes such as OPA, and MFN2. In summary, our findings suggest that Neb and Met treatment significantly ameliorated the LPS-induced cytotoxicity and oxidative stress. Additionally, these findings suggest that Neb but not Met significantly down-regulates LPS-induced proinflammatory factors, probably by enhancing mitochondrial biogenesis and fusion.

Nitric Oxide-Releasing Platforms for Treating Cardiovascular Disease

Cardiovascular disease (CVD) is the first leading cause of death globally. Nitric oxide (NO) is an important signaling molecule that mediates diverse processes in the cardiovascular system, thereby providing a fundamental basis for NO-based therapy of CVD. At present, numerous prodrugs have been developed to release NO in vivo. However, the clinical application of these prodrugs still faces many problems, including the low payloads, burst release, and non-controlled delivery. To address these, various biomaterial-based platforms have been developed as the carriers to deliver NO to the targeted tissues in a controlled and sustained manner. This review aims to summarize recent developments of various therapeutic platforms, engineered to release NO for the treatment of CVD. In addition, two potential strategies to improve the effectiveness of existing NO therapy are also discussed, including the combination of NO-releasing platforms and either hydrogen sulfide-based therapy or stem cell therapy. Hopefully, some NO-releasing platforms may provide important therapeutic benefits for CVD.

Inhibition of eNOS Partially Blunts the Beneficial Effects of Nebivolol on Angiotensin II-Induced Signaling in H9c2 Cardiomyoblasts

We have recently illustrated that nebivolol can inhibit angiotensin II (Ang II)-mediated signaling in cardiomyoblasts; however, to date, the detailed mechanism for the beneficial effects of nebivolol has not been studied. Here, we investigated whether the inhibition of NO bioavailability by blocking eNOS (endothelial nitric oxide synthase) using L-NG-nitroarginine methyl ester (L-NAME) would attenuate nebivolol-mediated favorable effects on Ang II-evoked signaling in H9c2 cardiomyoblasts. Our data reveal that the nebivolol-mediated antagonistic effects on Ang II-induced oxidative stress were retreated by concurrent pretreatment with L-NAME and nebivolol. Similarly, the expressions of pro-inflammatory markers TNF-α and iNOS stimulated by Ang II were not decreased with the combination of nebivolol plus L-NAME. In contrast, the nebivolol-induced reduction in the Ang II-triggered mTORC1 pathway and the mRNA levels of hypertrophic markers ANP, BNP, and β-MHC were not reversed with the addition of L-NAME to nebivolol. In compliance with these data, the inhibition of eNOS by L-N⁵-(1-Iminoethyl) ornithine (LNIO) and its upstream regulator AMP-activated kinase (AMPK) with compound C in the presence of nebivolol showed effects similar to those of the L-NAME plus nebivolol combination on Ang II-mediated signaling. Pretreatment with either compound C plus nebivolol or LNIO plus nebivolol showed similar effects to those of the L-NAME plus nebivolol combination on Ang II-mediated signaling. In conclusion, our data indicate that the rise in NO bioavailability caused by nebivolol via the stimulation of AMPK/eNOS signaling is key for its anti-inflammatory and antioxidant properties but not for its antihypertrophic response upon Ang II stimulation.

Ellagic Acid Prevents Myocardial Infarction-induced Left Ventricular Diastolic Dysfunction in Ovariectomized Rats

Estrogen deficiency is associated with increased oxidative stress, which can contribute to left ventricular diastolic dysfunction (LVDD). We hypothesized that oral treatment with ellagic acid (EA), a potent and natural antioxidant compound, can improve MI-induced LVDD in ovariectomized rats, by reducing the formation of reactive oxygen species (ROS). Ovariectomized rats MI-induced LVDD followed by treatment with vehicle (DD) or EA (DD+EA) for 4 weeks. Non-LVDD-induced rats treated with vehicle (S) or EA (S+EA) were used as controls. Left ventricular systolic pressure: LVSP; left ventricular end-diastolic pressure: LVEDP; maximum rate of pressure rise: +dP/dt and fall: -dP/dt) were evaluated in all animals after treatment. Left ventricle superoxide anion formation was quantified in situ by fluorescence. Phospho-CAMKII, SOD2, catalase and gp91-phox abundances were evaluated by Western blot analyses. SOD and catalase activities were measured by spectrophotometry. The results showed that the LVEDP was significantly increased in both DD and DD+EA groups compared to S and S+EA. However, LVEDP in the DD+EA group was significantly decreased compared to DD, indicating an EA-mediated effect. In the DD group, superoxide production and gp91-phox protein abundance were increased while SOD2 abundance was decreased when compared to the S and S+EA groups. An increase in SOD activity was also observed in the DD+EA group. EA treatment reduced CaMKII phosphorylation in the DD+EA group compared to the DD. We concluded that EA treatment attenuated diastolic dysfunction in our experimental model, via reduction of ROS and CaMKII activity, indicating EA as a promising natural therapeutic option for cardiac dysfunction.

Quantification of myocardial fibrosis using noninvasive T2-mapping magnetic resonance imaging: Preclinical models of aging and pressure overload

Noninvasive imaging of cardiac fibrosis is important for early diagnosis and intervention in chronic heart diseases. Here, we investigated whether noninvasive, contrast agent-free MRI T₂ -mapping can quantify myocardial fibrosis in preclinical models of aging and pressure overload. Myocardial fibrosis and remodeling were analyzed in two animal models: (i) aging (15-month-old male CF-1 mice vs. young 6- to 8-week-old mice), and (ii) pressure overload (PO; by transverse aortic constriction in 4- to 5-month-old male C57BL/6 mice vs. sham-operated for 14 days). In vivo T₂ -mapping was performed by acquiring data during the isovolumic and early diastolic phases, with a modified respiratory and ECG-triggered multiecho TurboRARE sequence on a 7-T MRI. Cine MRI provided cardiac morphology and function. A quantitative segmentation method was developed to analyze the in vivo T₂ -maps of hearts at midventricle, apex, and basal regions. The cardiac fibrosis area was analyzed ex vivo by picro sirius red (PSR) staining. Both aged and pressure-overloaded hearts developed significant myocardial contractile dysfunction, cardiac hypertrophy, and interstitial fibrosis. The aged mice had two phenotypes, fibrotic and mild-fibrotic. Notably, the aged fibrotic subgroup and the PO mice showed a marked decrease in T₂ relaxation times (25.3 ± 0.6 in aged vs. 29.9 ± 0.7 ms in young mice, p = 0.002; and 24.3 ± 1.7 in PO vs. 28.7 ± 0.7 ms in shams, p = 0.05). However, no significant difference in T₂ was detected between the aged mild-fibrotic subgroup and the young mice. Accordingly, an inverse correlation between myocardial fibrosis percentage (FP) and T₂ relaxation time was derived (R²  = 0.98): T₂ (ms) = 30.45 - 1.05 × FP. Thus, these results demonstrate a statistical agreement between T₂ -map-quantified fibrosis and PSR staining in two different clinically relevant animal models. In conclusion, T₂ -mapping MRI is a promising noninvasive contrast agent-free quantitative technique to characterize myocardial fibrosis.

Comparative beneficial effects of nebivolol and nebivolol/valsartan combination against mitochondrial dysfunction in angiotensin II-induced pathology in H9c2 cardiomyoblasts

OBJECTIVES

Considering the complementary nature of signalling mechanisms and the therapeutic effects of nebivolol, a β1-adrenoreceptor antagonist, and valsartan, an angiotensin receptor blocker (ARB), here we aimed to investigate whether nebivolol/valsartan combination would complement the cardioprotective effects of nebivolol on angiotensin II (ANG II)-induced pathology in H9c2 cardiomyoblasts.

METHODS

H9c2 cardiomyoblasts were used to investigate the protective effects of nebivolol and nebivolol and valsartan combination against ANG II-induced pathology. Reactive oxygen species (ROS) generation was determined by 2',7'-dichlorofluorescein diacetate (DCFDA) and MitoSOX Red staining. Real-time PCR and immunoblotting were employed to quantify the changes in mRNA and protein expression levels, respectively.

KEY FINDINGS

Our data revealed that pretreatment with nebivolol and nebivolol/valsartan combination significantly reduced ANG II-induced oxidative stress and mTORC1 signalling. Concurrently, ANG II-induced activation of inflammatory cytokines and fetal gene expressions were significantly suppressed by nebivolol and nebivolol/valsartan combination. Pretreatment with nebivolol and nebivolol/valsartan combination alleviated ANG II-induced impairment of mitochondrial biogenesis by restoring the gene expression levels of PGC-1α, TFAM, NRF-1 and SIRT3. Our data further show that nebivolol and nebivolol/valsartan combination mediated up-regulation in mitochondrial biogenesis is accompanied by decrease in ANG II-stimulated mitochondrial ROS generation as well as increase in expression of mitochondrial fusion genes MFN2 and OPA1, indicative of improved mitochondrial dynamics.

SUMMARY

These findings suggest that both nebivolol and nebivolol/valsartan combination exert protective effects on ANG II-induced mitochondrial dysfunction by alleviating its biogenesis and dynamics. Moreover, addition of valsartan to nebivolol do not produce any additive effects compared with nebivolol alone on ANG II-induced cardiac pathology.

ApoA-I mimetic does not improve left ventricular diastolic dysfunction in rabbits without aortic valve stenosis

BACKGROUND

We previously demonstrated that high-density lipoprotein (HDL) infusions may improve left ventricular diastolic dysfunction (LVDD) in an aortic valve stenosis (AVS) model. Whether the benefit was direct or mediated by the observed reduction in AVS severity is not clear. Here, we aimed to test the direct effect of an ApoA-I mimetic on LVDD in the absence of AVS.

METHODS

Rabbits were exposed to three different protocols to develop LVDD. First, rabbits were exposed to 0.5% cholesterol-rich diet for an average of 17 weeks. Second, rabbits were subjected to surgical ascending aortic constriction (AAC), to mimic the effect of fixed reduced aortic valve area, and studied after 10 weeks. The third model combined both cholesterol-enriched diet (for 12 weeks) and surgical AAC. The control group consisted of age-matched rabbits under normal diet. After development of LVDD, rabbits were randomized to receive infusions of saline or apoA-I mimetic (25 mg/kg) 3 times per week for 4 weeks. Detailed cardiac structure and function measurements were assessed at baseline and weekly during treatment period. Histological and molecular analyses were performed on LV samples.

RESULTS

In the three models, echocardiographic results showed development of LVDD over time, with preserved LV systolic and aortic valve functions versus controls. ApoA-I mimetic infusions did not significantly improve echocardiographic parameters nor molecular markers of cardiac inflammation, oxidative stress and fibrosis.

CONCLUSION

ApoA-I mimetic therapy did not directly improve LVDD. These results indicate that previously observed changes of LVDD were caused by AVS improvement induced by this treatment.

Longevity genes, cardiac ageing, and the pathogenesis of cardiomyopathy: implications for understanding the effects of current and future treatments for heart failure

The two primary molecular regulators of lifespan are sirtuin-1 (SIRT1) and mammalian target of rapamycin complex 1 (mTORC1). Each plays a central role in two highly interconnected pathways that modulate the balance between cellular growth and survival. The activation of SIRT1 [along with peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α) and adenosine monophosphate-activated protein kinase (AMPK)] and the suppression of mTORC1 (along with its upstream regulator, Akt) act to prolong organismal longevity and retard cardiac ageing. Both activation of SIRT1/PGC-1α and inhibition of mTORC1 shifts the balance of cellular priorities so as to promote cardiomyocyte survival over growth, leading to cardioprotective effects in experimental models. These benefits may be related to direct actions to modulate oxidative stress, organellar function, proinflammatory pathways, and maladaptive hypertrophy. In addition, a primary shared benefit of both SIRT1/PGC-1α/AMPK activation and Akt/mTORC1 inhibition is the enhancement of autophagy, a lysosome-dependent degradative pathway, which clears the cytosol of dysfunctional organelles and misfolded proteins that drive the ageing process by increasing oxidative and endoplasmic reticulum stress. Autophagy underlies the ability of SIRT1/PGC-1α/AMPK activation and Akt/mTORC1 suppression to extend lifespan, mitigate cardiac ageing, alleviate cellular stress, and ameliorate the development and progression of cardiomyopathy; silencing of autophagy genes abolishes these benefits. Loss of SIRT1/PGC-1α/AMPK function or hyperactivation of Akt/mTORC1 is a consistent feature of experimental cardiomyopathy, and reversal of these abnormalities mitigates the development of heart failure. Interestingly, most treatments that have been shown to be clinically effective in the treatment of chronic heart failure with a reduced ejection fraction have been reported experimentally to exert favourable effects to activate SIRT1/PGC-1α/AMPK and/or suppress Akt/mTORC1, and thereby, to promote autophagic flux. Therefore, the impairment of autophagy resulting from derangements in longevity gene signalling is likely to represent a seminal event in the evolution and progression of cardiomyopathy.

Nebivolol Prevents Up-Regulation of Nox2/NADPH Oxidase and Lipoperoxidation in the Early Stages of Ethanol-Induced Cardiac Toxicity

Changes in redox state are described in the early stages of ethanol-induced cardiac toxicity. Here, we evaluated whether nebivolol would abrogate ethanol-induced redox imbalance in the heart. Male Wistar rats were treated with a solution of ethanol (20% v/v) for 3 weeks. Treatment with nebivolol (10 mg/kg/day; p.o. gavage) prevented the increase of both superoxide (O2•-) and thiobarbituric acid reactive substances (TBARS) in the left ventricle of rats chronically treated with ethanol. Neither ethanol nor nebivolol affected the expression of Nox4, p47phox, or Rac-1. Nebivolol prevented ethanol-induced increase of Nox2 expression in the left ventricle. Superoxide dismutase (SOD) activity as well as the concentration of reduced glutathione (GSH) was not altered by ethanol or nebivolol. Augmented catalase activity was detected in the left ventricle of both ethanol- and nebivolol-treated rats. Treatment with nebivolol, but not ethanol increased eNOS expression in the left ventricle. No changes in the activity of matrix metalloproteinase (MMP)2 or in the expressions of MMP2, MMP9, and tissue inhibitor metalloproteinase (TIMP)1 were detected after treatment with ethanol or nebivolol. However, ethanol increased the expression of TIMP2, and this response was prevented by nebivolol. Our results provided novel insights into the mechanisms underlying the early stages of the cardiac injury induced by ethanol consumption. We demonstrated that Nox2/NADPH oxidase-derived ROS play a role in ethanol-induced lipoperoxidation and that this response was prevented by nebivolol. In addition, we provided evidence that MMPs are not activated in the early stages of ethanol-induced cardiac toxicity.

Nebivolol combined with tetrahydrobiopterin affects diastolic function in spontaneously hypertensive rats via the nitric oxide/cyclic guanosine monophosphate signalling pathway

BACKGROUND

Hypertension is the the primary cause of diastolic heart failure. Oxidative stress plays an important role in cardiac diastolic dysfunction caused by hypertension. The occurrence of oxidative stress is related to the level of nitric oxide (NO) in the body. Tetrahydrobiopterin (BH4) is an essential cofactor for NO synthesis. Nebivolol can reduce myocardial oxidative stress and increase NO activity. Therefore, we investigated the effects of monotherapy or combination therapy of different doses of BH4 and nebivolol on cardiac diastolic function in spontaneously hypertensive rats, and preliminarily expounded the related mechanisms.

METHODS

Left ventricular function was evaluated by non-invasive echocardiographic assessment and invasive right carotid artery catheterization methods. ELISA was used to measure myocardial 3-nitrotyrosine content, NO production, and cyclic guanosine monophosphate (cGMP) concentration in the myocardium; quantitative real-time PCR (qRT-PCR) was used to determine endothelial nitric oxide synthase (eNOS), phospholamban and sarcoplasmic reticulum Ca2+-ATPase 2a (SERCA2a) mRNA expression levels; Western blot was used to detect the protein expression levels of eNOS and eNOS dimers in myocardial tissue, and immunohistochemical detection of cGMP expression in the myocardium was performed.

RESULTS

Studies have shown that compared with those in the control group, NO generation and the expression level of myocardial eNOS mRNA, eNOS expression of dimers, phospholamban, SERCA2a and cGMP increased significantly after the combined intervention of BH4 and nebivolol, while the expression of 3-nitrotyrosine was significantly decreased.

CONCLUSIONS

The combined treatment group had a synergistic effect on reducing myocardial oxidative stress, increasing eNOS content, and increasing NO production, and had a more obvious protective effect on diastolic dysfunction through the nitric oxide/cyclic guanosine monophosphate (NO/cGMP) pathway.

Sequential nephron blockade with combined diuretics improves diastolic function in patients with resistant hypertension

AIMS

Hypertension is a major contributor to cardiac diastolic dysfunction. Different therapeutics strategies have been proposed to control blood pressure (BP), but their independent impact on cardiac function remains undetermined. In patients with resistant hypertension, we compared the changes in cardiac parameters between two strategies based on sequential nephron blockade (NBD) with a combination of diuretics or sequential renin-angiotensin system blockade (RASB).

METHODS AND RESULTS

After a 4-week period where all patients received Irbesartan 300 mg/day + hydrochlorothiazide 12.5 mg/day + amlodipine 5 mg/day, 140 resistant hypertension patients (54.8 ± 11.1 years, 76% men, mean duration with hypertension: 13.1 ± 10.5 years, no previous history of heart failure or current symptoms of congestive heart failure) were randomized 1:1 to the NBD regimen or to the RASB regimen at week 0 (W0, baseline). Treatment intensity was increased at week 4, 8, or 10 if home BP was ≥135/85 mmHg, by sequentially adding 25 mg spironolactone, 20-40 mg furosemide, and 5 mg amiloride (NBD group) or 5-10 mg ramipril and 5-10 mg bisoprolol (RASB group). No other antihypertensive drug was allowed during the study. BP, BNP levels, and echocardiographic parameters were assessed at weeks 0 and 12. The baseline characteristics, laboratory parameters, and plasma hormones (BNP, renin, and aldosterone) and cardiac echocardiographic parameters did not significantly differ between the NBD and the RASB groups. Over 12 weeks, BNP levels significantly decreased in NBD but increased in RASB (mean [CI 95%] change in log-transformed BNP levels: -43% [-67%; -23%] vs. +55% [46%; 62%] in NBD vs. RASB, respectively, P < 0.0001). Similarly, the proportion of patients presenting ≥2 echocardiographic criteria of diastolic dysfunction decreased between baseline and W12 from 31% to 3% in NBD but increased from 19% to 32% in RASB (P = 0.0048). As compared with RASB, NBD induced greater decrease in ambulatory systolic BP (P < 0.0001), pulse pressure (P < 0.0001), and systemic vascular resistance (P < 0.005). In multivariable linear regression analyses, NBD treatment was significantly associated with decreased BNP levels (adjusted ß: -46.41 ± 6.99, P < 0.0001) independent of age, gender, renal function, and changes in BPs or heart rate.

CONCLUSIONS

In patients with resistant hypertension, nephron blockade with a combination of diuretics significantly improves cardiac markers of diastolic dysfunction independently of BP lowering.

Molecular, Cellular, and Clinical Evidence That Sodium-Glucose Cotransporter 2 Inhibitors Act as Neurohormonal Antagonists When Used for the Treatment of Chronic Heart Failure

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of cardiovascular death and hospitalization for heart failure in patients with chronic heart failure. Initially, these drugs were believed to have a profile similar to diuretics or hemodynamically active drugs, but they do not rapidly reduce natriuretic peptides or cardiac filling pressures, and they exert little early benefit on symptoms, exercise tolerance, quality of life, or signs of congestion. Clinically, the profile of SGLT2 inhibitors resembles that of neurohormonal antagonists, whose benefits emerge gradually during sustained therapy. In experimental models, SGLT2 inhibitors produce a characteristic pattern of cellular effects, which includes amelioration of oxidative stress, mitigation of mitochondrial dysfunction, attenuation of proinflammatory pathways, and a reduction in myocardial fibrosis. These cellular effects are similar to those produced by angiotensin converting enzyme inhibitors, β-blockers, mineralocorticoid receptor antagonists, and neprilysin inhibitors. At a molecular level, SGLT2 inhibitors induce transcriptional reprogramming of cardiomyocytes that closely mimics that seen during nutrient deprivation. This shift in signaling activates the housekeeping pathway of autophagy, which clears the cytosol of dangerous cytosolic constituents that are responsible for cellular stress, thereby ameliorating the development of cardiomyopathy. Interestingly, similar changes in cellular signaling and autophagic flux have been seen with inhibitors of the renin-angiotensin system, β-blockers, mineralocorticoid receptor antagonists, and neprilysin inhibitors. The striking parallelism of these molecular, cellular, and clinical profiles supports the premise that SGLT2 inhibitors should be regarded as neurohormonal antagonists when prescribed for the treatment of heart failure with a reduced ejection fraction.

Effects of Tetrahydrobiopterin Combined with Nebivolol on Cardiac Diastolic Function in SHRs

This study aimed to evaluate the effects of combined use of tetrahydrobiopterin (BH4) and nebivolol on cardiac diastolic dysfunction in spontaneously hypertensive rats (SHRs). Twelve-week-old male SHRs were treated with BH4, nebivolol, or a combination of both. Left ventricle function was evaluated, and reactive oxygen species (ROS) production (including dihydroethidium (DHE) and 3-nitrotyrosine (3-NT)), nitric oxide synthase (NOS) activity and the level of NO in myocardial tissue were determined. The expression levels of endothelial NOS (eNOS), phospholamban (PLN), sarcoplasmic reticulum Ca2+ ATPase (SERCA2a), β3-adrenoceptor, cyclic guanosine monophosphate (cGMP), and protein kinase G (PKG) were assayed. Treatment with BH4, nebivolol, or both reversed the noninvasive indexes of diastolic function, including E/E' and E'/A', and the invasive indexes, including time constant of isovolumic left ventricle (LV) relaxation (tau), -dP/dtmin, -dP/dtmin/LV systolic pressure (LVSP), and LV end-diastolic pressure (LVEDP) in SHRs. mRNA and protein expression levels of eNOS dimer, phosphorylated PLN, SERCA2a, cGMP, and PKG in the myocardium of treated SHRs were significantly up-regulated compared with those in control rats (p < 0.05 or p < 0.01). The expression levels of 3-NT and DHE were reduced in all treated groups (p < 0.05 or p < 0.01). Notably, combined use of BH4 and nebivolol had better cardioprotective effects than monotherapies. BH4 or nebivolol has a protective effect on diastolic dysfunction in SHRs, and BH4 combined with nebivolol may exert a synergistically cardioprotective effect through activation of β3-adrenoceptor and the NO/cGMP/PKG signaling pathway.

Cardiac β3 -adrenoceptors-A role in human pathophysiology?

As β₃ -adrenoceptors were first demonstrated to be expressed in adipose tissue they have received much attention for their metabolic effects in obesity and diabetes. After the existence of this subtype had been suggested to be present in the heart, studies focused on its role in cardiac function. While the presence and functional role of β₃ -adrenoceptors in the heart has not uniformly been detected, there is a broad consensus that they become up-regulated in pathological conditions associated with increased sympathetic activity such as heart failure and diabetes. When detected, the β₃ -adrenceptor has been demonstrated to mediate negative inotropic effects in an inhibitory G protein-dependent manner through the NO-cGMP-PKG signalling pathway. Whether these negative inotropic effects provide protection from the adverse effects induced by overstimulation of β₁ /β₂ -adrenoceptors or in themselves are potentially harmful is controversial, but ongoing clinical studies in patients with congestive heart failure are testing the hypothesis that β₃ -adrenceptor agonism has a beneficial effect. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.

Influence of beta-blockers on mechanical dyssynchrony and cardiac remodeling in patients with ischemic chronic heart failure in the setting of revascularization

Introduction: Diastolic dysfunction (DD) and cardiac dyssynchrony (DS) are involved in the progression of chronic heart failure (CHF). A comparative analysis was conducted of the effect of a 6-month course of nebivolol and bisoprolol on DD, DS and metalloproteinase-9 (MMP-9) level in patients with ischemic chronic heart failure with preserved ejection fraction (HFpEF) and with midrange ejection fraction (HFmrEF), as well as in patients with comorbid type 2 diabetes mellitus (T2DM) in the setting of coronary artery bypass grafting (CABG) after 6 months of therapy.

Materials and methods: The study included 308 patients with CHFFC I-II, left ventricular ejection fraction (LVEF) &gt;40%, who had undergone CABG. The average dose of nebivolol in patients with DS 6 months later was 5.1±2.6 mg/day, and bisoprolol – 4.9±2.4 mg/day. Echocardiography (EchoCG) and evaluation of MMP-9 in blood plasma were performed. Mechanical myocardial asynchrony was determined by calculating the standard deviation of time to peak systolic myocardial velocity (TS-SD) and maximum segment delay (TS12) using a 6-basal and-midsegment model.

Results and discussion: MMP-9 level in patients with CHF before CABG was 4.7 times higher (p&lt;0.001). MMP-9 correlated with LVEF (r=-0.60, p&lt;0.001), E/A (r=-0.49, p&lt;0.001), DT (r=0.43, p&lt;0.001), E` (r=-0.58, p&lt;0.001) and DS: TS12 (r=0.54, p&lt;0.001), TS-SD (r=0.49, p&lt;0.001). The six-month course of nebivolol improved the values of DS: TS12 – by 30% (p&lt;0.001), TS-SD – by 32% (p&lt;0.01) and reduced the MMP-9 level by 11% (p&lt;0.001). In patients with HFmrEF without DSnebivolol increased E/A by 19% (p&lt;0.01), E` – by 16% (P&lt;0.05), and decreased E/E’ by 9% (p&lt;0.05), DT – by 12% (p&lt;0.05). In patients with HFpEF and DM2, nebivolol reduced TS12 by 37% (p&lt;0.01), TS-SD – by 29% (p&lt;0.05) and MMP-9 – by 13% (p&lt;0.05).

Conclusion: The positive effect of nebivolol on the DS, DD of the LV in patients with HFpEF, HFmrEF and with comorbid type 2 diabetes mellitus. The six-month course of nebivolol decreased the MMP-9 level in patients with ischemic CHF after CABG, including patients with T2DM.

Epoxyeicosatrienoic Acid-Based Therapy Attenuates the Progression of Postischemic Heart Failure in Normotensive Sprague-Dawley but Not in Hypertensive Ren-2 Transgenic Rats

Epoxyeicosatrienoic acids (EETs) and their analogs have been identified as potent antihypertensive compounds with cardio- and renoprotective actions. Here, we examined the effect of EET-A, an orally active EET analog, and c-AUCB, an inhibitor of the EETs degrading enzyme soluble epoxide hydrolase, on the progression of post-myocardial infarction (MI) heart failure (HF) in normotensive Hannover Sprague-Dawley (HanSD) and in heterozygous Ren-2 transgenic rats (TGR) with angiotensin II-dependent hypertension. Adult male rats (12 weeks old) were subjected to 60-min left anterior descending (LAD) coronary artery occlusion or sham (non-MI) operation. Animals were treated with EET-A and c-AUCB (10 and 1 mg/kg/day, respectively) in drinking water, given alone or combined for 5 weeks starting 24 h after MI induction. Left ventricle (LV) function and geometry were assessed by echocardiography before MI and during the progression of HF. At the end of the study, LV function was determined by catheterization and tissue samples were collected. Ischemic mortality due to the incidence of sustained ventricular fibrillation was significantly higher in TGR than in HanSD rats (35.4 and 17.7%, respectively). MI-induced HF markedly increased LV end-diastolic pressure (P_ed) and reduced fractional shortening (FS) and the peak rate of pressure development [+(dP/dt)_max] in untreated HanSD compared to sham (non-MI) group [P_ed: 30.5 ± 3.3 vs. 9.7 ± 1.3 mmHg; FS: 11.1 ± 1.0 vs. 40.8 ± 0.5%; +(dP/dt)_max: 3890 ± 291 vs. 5947 ± 309 mmHg/s]. EET-A and c-AUCB, given alone, tended to improve LV function parameters in HanSD rats. Their combination amplified the cardioprotective effect of single therapy and reached significant differences compared to untreated HanSD controls [P_ed: 19.4 ± 2.2 mmHg; FS: 14.9 ± 1.0%; +(dP/dt)_max: 5278 ± 255 mmHg/s]. In TGR, MI resulted in the impairment of LV function like HanSD rats. All treatments reduced the increased level of albuminuria in TGR compared to untreated MI group, but neither single nor combined EET-based therapy improved LV function. Our results indicate that EET-based therapy attenuates the progression of post-MI HF in HanSD, but not in TGR, even though they exhibited renoprotective action in TGR hypertensive rats.

Hirudin Protects Ang II-Induced Myocardial Fibroblasts Fibrosis by Inhibiting the Extracellular Signal-Regulated Kinase1/2 (ERK1/2) Pathway

BACKGROUND Myocardial fibrosis is closely related to all types of cardiovascular diseases. Hirudin is widely used in the prevention and treatment of cardiovascular diseases and cancers. In this study, we examined the potential role(s) and mechanism of hirudin in angiotensin II (Ang II)-induced myocardial fibrosis. MATERIAL AND METHODS The viability of myocardial fibroblasts, and reactive oxygen species (ROS) rates were measured respectively using cell counting kit-8 (CCK-8) and flow cytometry. Malondialdehyde (MDA) content, the activities of lactate dehydrogenase (LDH), and superoxide dismutase (SOD) were detected by the respective kits. The mRNA and protein levels of fibrosis-related factors were separately assessed by qRT-PCR and western blot. RESULTS Our data revealed that hirudin suppressed the viability of myocardial fibroblasts, and that it relieved the proliferation induced by Ang II in a dose-dependent manner. We also found that hirudin reduced ROS production, LDH activity, and MDA content; however, it enhanced SOD activity. Moreover, while hirudin significantly downregulated the levels of matrix metalloproteinase-2 (MMP-2), MMP-9, fibronectin (FN), transforming growth factor beta 1 (TGF-β1), collagen-I (COL-I), and COL-III, it upregulated the expression level of tissue inhibitor of metalloproteinases-2 (TIMP-2). Furthermore, phosphorylated extracellular signal-regulated kinase1/2 (p-ERK1/2) was decreased by hirudin, compared to the Ang-II group. CONCLUSIONS Hirudin depressed Ang II-induced myocardial fibroblasts via inhibiting oxidative stress, regulating fibrosis-related factors, and repressing the ERK1/2 pathway.

The relaxin peptide family - potential future hope for neuroprotective therapy? A short review

Since its discovery in the 1920's the relaxin peptide hormone family has not only grown in number to now seven members (relaxin-1, relaxin-2, relaxin-3, insulin-like peptide (INSL) 3, INSL4, INSL5 and INSL6), but ever more effects, suchs as vasodilatory, angiogenic, anti-apoptopic, anti-fibriotic and anti-inflammatory, have been linked to them. While relaxin-2 has mainly been investigated in the context of cardiac protection, most comprehensively in the RELAX-AHF and RELAX AHF2 studies, a small number of studies have furthermore assessed the potential neuroprotective effects of especially relaxin-2 and other members of the relaxin family. In this short review we summarise and discuss recent efforts to utilize relaxin hormones for neuroprotection and point out potential future fields of research and translational applications. While many questions still need to be answered, the promising results of the available studies definitely warrant future well-designed studies on neuroprotection by relaxin peptides.

Insulin and β Adrenergic Receptor Signaling: Crosstalk in Heart

Recent advances show that insulin may affect β adrenergic receptor (βAR) signaling in the heart to modulate cardiac function in clinically relevant states, such as diabetes mellitus (DM) and heart failure (HF). Conversely, activation of βAR regulates cardiac glucose uptake and promotes insulin resistance (IR) in HF. Here, we discuss the recent characterization of the interaction between the cardiac insulin receptor (InsR) and βAR in the myocardium, in which insulin stimulation crosstalks with cardiac βAR via InsR substrate (IRS)-dependent and G-protein receptor kinase 2 (GRK2)-mediated phosphorylation of β₂AR. The insulin-induced phosphorylation promotes β₂AR coupling to G_i and expression of phosphodiesterase 4D, which both inhibit cardiac adrenergic signaling and compromise cardiac contractile function. These recent developments could support new approaches for the effective prevention or treatment of obesity- or DM-related HF.

Increase of cortical cerebral blood flow and further cerebral microcirculatory effects of Serelaxin in a sheep model

Serelaxin, recombinant human relaxin-2, modulates endothelial vasodilatory functionality and is under evaluation for treatment of acute heart failure. Little is known about acute effects on cerebral perfusion. We tested the hypothesis that Serelaxin might also have effects on the cerebral microcirculation in a sheep model, which resembles human brain structure quite well. We used laser Doppler flowmetry and sidestream dark-field (SDF) imaging techniques, which are reliable tools to continuously assess dynamic changes in cerebral perfusion. Laser Doppler flowmetry shows that bolus injection of 30 μg Serelaxin/kg body wt induces an increase (P = 0.006) to roughly 150% of cortical cerebral blood flow (CBF), whereas subcortical CBF remains unchanged (P = 0.688). The effects on area-dependent CBF were significantly different after the bolus injection (P = 0.042). Effects on cortical CBF were further confirmed by SDF imaging. The bolus injection of Serelaxin increased total vessel density to 127% (P = 0.00046), perfused vessel density to 145% (P = 0.024), and perfused capillary density to 153% (P = 0.024). Western blotting confirmed the expression of relaxin receptors RXFP1 and truncated RXFP2-variants in the respective brain regions, suggesting a possible contribution of RXFP1 on the effects of Serelaxin. In conclusion, the injection of a high dose of Serelaxin exerts quick effects on the cerebral microcirculation. Therefore, Serelaxin might be suitable to improve cortical microcirculation and exert neuroprotective effects in clinically relevant scenarios that involve cortical hypoperfusion. These findings need to be confirmed in relevant experimental settings involving cerebral cortical hypoperfusion and can possibly be translated into clinical practice.

Differential effects of nebivolol vs. metoprolol on microvascular function in hypertensive humans

Use of β-adrenergic receptor (AR) blocker is associated with increased risk of fatigue and exercise intolerance. Nebivolol is a newer generation β-blocker, which is thought to avoid this side effect via its vasodilating property. However, the effects of nebivolol on skeletal muscle perfusion during exercise have not been determined in hypertensive patients. Accordingly, we performed contrast-enhanced ultrasound perfusion imaging of the forearm muscles in 25 untreated stage I hypertensive patients at rest and during handgrip exercise at baseline or after 12 wk of treatment with nebivolol (5-20 mg/day) or metoprolol succinate (100-300 mg/day), with a subsequent double crossover for 12 wk. Metoprolol and nebivolol each induced a reduction in the resting blood pressure and heart rate (130.9 ± 2.6/81.7 ± 1.8 vs. 131.6 ± 2.7/80.8 ± 1.5 mmHg and 63 ± 2 vs. 64 ± 2 beats/min) compared with baseline (142.1 ± 2.0/88.7 ± 1.4 mmHg and 75 ± 2 beats/min, respectively, both P < 0.01). Metoprolol significantly attenuated the increase in microvascular blood volume (MBV) during handgrip at 12 and 20 repetitions/min by 50% compared with baseline (mixed-model P < 0.05), which was not observed with nebivolol. Neither metoprolol nor nebivolol affected microvascular flow velocity (MFV). Similarly, metoprolol and nebivolol had no effect on the increase in the conduit brachial artery flow as determined by duplex Doppler ultrasound. Thus our study demonstrated a first direct evidence for metoprolol-induced impairment in the recruitment of microvascular units during exercise in hypertensive humans, which was avoided by nebivolol. This selective reduction in MBV without alteration in MFV by metoprolol suggested impaired vasodilation at the precapillary arteriolar level.

Renin overexpression leads to increased titin-based stiffness contributing to diastolic dysfunction in hypertensive mRen2 rats

Hypertension (HTN) is a major risk factor for heart failure. We investigated the influence of HTN on cardiac contraction and relaxation in transgenic renin overexpressing rats (carrying mouse Ren-2 renin gene, mRen2, n = 6). Blood pressure (BP) was measured. Cardiac contractility was characterized by echocardiography, cellular force measurements, and biochemical assays were applied to reveal molecular mechanisms. Sprague-Dawley (SD) rats (n = 6) were used as controls. Transgenic rats had higher circulating renin activity and lower cardiac angiotensin-converting enzyme two levels. Systolic BP was elevated in mRen2 rats (235.11 ± 5.32 vs. 127.03 ± 7.56 mmHg in SD, P < 0.05), resulting in increased left ventricular (LV) weight/body weight ratio (4.05 ± 0.09 vs. 2.77 ± 0.08 mg/g in SD, P < 0.05). Transgenic renin expression had no effect on the systolic parameters, such as LV ejection fraction, cardiomyocyte Ca(2+)-activated force, and Ca(2+) sensitivity of force production. In contrast, diastolic dysfunction was observed in mRen2 compared with SD rats: early and late LV diastolic filling ratio (E/A) was lower (1.14 ± 0.04 vs. 1.87 ± 0.08, P < 0.05), LV isovolumetric relaxation time was longer (43.85 ± 0.89 vs. 28.55 ± 1.33 ms, P < 0.05), cardiomyocyte passive tension was higher (1.74 ± 0.06 vs. 1.28 ± 0.18 kN/m(2), P < 0.05), and lung weight/body weight ratio was increased (6.47 ± 0.24 vs. 5.78 ± 0.19 mg/g, P < 0.05), as was left atrial weight/body weight ratio (0.21 ± 0.03 vs. 0.14 ± 0.03 mg/g, P < 0.05). Hyperphosphorylation of titin at Ser-12742 within the PEVK domain and a twofold overexpression of protein kinase C-α in mRen2 rats were detected. Our data suggest a link between the activation of renin-angiotensin-aldosterone system and increased titin-based stiffness through phosphorylation of titin's PEVK element, contributing to diastolic dysfunction.

Long-term prescription of beta-blocker delays the progression of heart failure with preserved ejection fraction in patients with hypertension: A retrospective observational cohort study

BACKGROUND

Hypertension complicated with left ventricular hypertrophy (LVH) and diastolic dysfunction is one of the most common risks for heart failure with preserved ejection fraction (HFpEF). This study was designed to evaluate the influences of long-term beta-blocker prescription in these patients.

METHODS

This retrospective analysis included eligible patients diagnosed with hypertension, LVH (left ventricular (LV) mass index >125 g/m(2) for men and >110 g/m(2) for women) and suspected diastolic dysfunction (E/E' ratio between 8 and 15) and without clinical signs or symptoms of heart failure in our hospital medical record database (January 2005-December 2009). A total of eligible 1498 patients were enrolled, of whom 803 received beta-blocker prescription and 695 accepted non-beta-blocker therapy.

RESULTS

With a median follow-up of 7.2 years, the new-onset symptomatic HFpEF occurred in 48 of 803 patients in the beta-blocker group (6.0%) and 92 of 695 patients in the non-beta-blocker group (13.2%, p < 0.001). Beta-blockers also generated more prominent improvement in diastolic function and LVH. And Cox proportional hazards model revealed that beta-blocker (hazard ratio (HR) 0.327, 95% confidence interval (CI): 0.121-0.540, p = 0.009) or angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker (ACEI/ARB) exposure (HR 0.422, 95% CI: 0.210-0.699, p = 0.015) was associated with a reduced risk of new onset of symptomatic HFpEF, and the elevation of LVMI (HR 1.210, 95% CI: 1.069-1.362, p = 0.040) or E/E' (HR 1.398, 95% CI: 1.306-1.541, p = 0.032) was associated with a high risk of new onset of symptomatic HFpEF.

CONCLUSIONS

Long-term beta-blocker exposure was associated with protective effects in terms of the incidence of new-onset symptomatic HFpEF, LV diastolic dysfunction and LVH, which might be beneficial for the delay of HFpEF progression.

AMPK in cardiac fibrosis and repair: Actions beyond metabolic regulation

Fibrosis is a general term encompassing a plethora of pathologies that span all systems and is marked by increased deposition of collagen. Injury of variable etiology gives rise to complex cascades involving several cell-types and molecular signals, leading to the excessive accumulation of extracellular matrix that promotes fibrosis and eventually leads to organ failure. Cardiac fibrosis is a dynamic process associated notably with ischemia, hypertrophy, volume- and pressure-overload, aging and diabetes mellitus. It has profoundly deleterious consequences on the normal architecture and functioning of the myocardium and is associated with considerable mortality and morbidity. The AMP-activated protein kinase (AMPK) is a ubiquitously expressed cellular energy sensor and an essential component of the adaptive response to cardiomyocyte stress that occurs during ischemia. Nevertheless, its actions extend well beyond its energy-regulating role and it appears to possess an essential role in regulating fibrosis of the myocardium. In this review paper, we will summarize the main elements and crucial players of cardiac fibrosis. In addition, we will provide an overview of the diverse roles of AMPK in the heart and discuss in detail its implication in cardiac fibrosis. Lastly, we will highlight the recently published literature concerning AMPK-targeting current therapy and novel strategies aiming to attenuate fibrosis.

Nebivolol and valsartan as a fixed-dose combination for the treatment of hypertension

INTRODUCTION

The fixed-dose combination of nebivolol and valsartan drug has been clinically evaluated and demonstrated to represent a unique combination of nebivolol, a selective β1-adrenoceptor antagonist and a β3-adrenoceptor agonist; β3 receptor activation increases endothelial nitric oxide and produces vasodilation. Valsartan is highly selective angiotensin AT1 receptor blocker and exerts its major pharmacological effect by decreasing angiotensin II-induced vasoconstriction and production of aldosterone. The addition of nebivolol counteracts the effects of increased angiotensin II concentrations resulting from potent AT1 blockade. This review describes a recently completed trial establishing the efficacy of the nebivolol/valsartan combination.

AREAS COVERED

This review provides a literature search of pertinent pharmacological and clinical data that describes the mechanisms of both drugs individually and the results of a clinical trial comparing fixed-dose combinations of nebivolol with valsartan as compared with each drug as monotherapy.

EXPERT OPINION

Fixed-dose combination drugs are intended to improve patient compliance and reduce drug costs, as well as to reduce long-term cardiovascular event rates and block counter-regulatory effects due to monotherapy. The vast majority of hypertensive patients will require at least two medications. We believe that the clinical evidence suggests that the combination of nebivolol with valsartan offers a definite clinical benefit, combining β1-adrenoceptor and angiotensin AT1 receptor blockade with β3 receptor activation and resultant increase in nitric oxide and vasodilation.

Small dedifferentiated cardiomyocytes bordering on microdomains of fibrosis: evidence for reverse remodeling with assisted recovery

With the perspective of functional myocardial regeneration, we investigated small cardiomyocytes bordering on microdomains of fibrosis, where they are dedifferentiated re-expressing fetal genes, and determined: (1) whether they are atrophied segments of the myofiber syncytium, (2) their redox state, (3) their anatomic relationship to activated myofibroblasts (myoFb), given their putative regulatory role in myocyte dedifferentiation and redifferentiation, (4) the relevance of proteolytic ligases of the ubiquitin-proteasome system as a mechanistic link to their size, and (5) whether they could be rescued from their dedifferentiated phenotype. Chronic aldosterone/salt treatment (ALDOST) was invoked, where hypertensive heart disease with attendant myocardial fibrosis creates the fibrillar collagen substrate for myocyte sequestration, with propensity for disuse atrophy, activated myoFb, and oxidative stress. To address phenotype rescue, 4 weeks of ALDOST was terminated followed by 4 weeks of neurohormonal withdrawal combined with a regimen of exogenous antioxidants, ZnSO4, and nebivolol (assisted recovery). Compared with controls, at 4 weeks of ALDOST, we found small myocytes to be: (1) sequestered by collagen fibrils emanating from microdomains of fibrosis and representing atrophic segments of the myofiber syncytia, (2) dedifferentiated re-expressing fetal genes (β-myosin heavy chain and atrial natriuretic peptide), (3) proximal to activated myoFb expressing α-smooth muscle actin microfilaments and angiotensin-converting enzyme, (4) expressing reactive oxygen species and nitric oxide with increased tissue 8-isoprostane, coupled to ventricular diastolic and systolic dysfunction, and (5) associated with upregulated redox-sensitive proteolytic ligases MuRF1 and atrogin-1. In a separate study, we did not find evidence of myocyte replication (BrdU labeling) or expression of stem cell antigen (c-Kit) at weeks 1-4 ALDOST. Assisted recovery caused complete disappearance of myoFb from sites of fibrosis with redifferentiation of these myocytes, loss of oxidative stress, and ubiquitin-proteasome system activation, with restoration of nitric oxide and improved ventricular function. Thus, small dedifferentiated myocytes bordering on microdomains of fibrosis can re-differentiate and represent a potential source of autologous cells for functional myocardial regeneration.

Endothelial dysfunction in cirrhosis: Role of inflammation and oxidative stress

This review describes the recent developments in the pathobiology of endothelial dysfunction (ED) in the context of cirrhosis with portal hypertension and defines novel strategies and potential targets for therapy. ED has prognostic implications by predicting unfavourable early hepatic events and mortality in patients with portal hypertension and advanced liver diseases. ED characterised by an impaired bioactivity of nitric oxide (NO) within the hepatic circulation and is mainly due to decreased bioavailability of NO and accelerated degradation of NO with reactive oxygen species. Furthermore, elevated inflammatory markers also inhibit NO synthesis and causes ED in cirrhotic liver. Therefore, improvement of NO availability in the hepatic circulation can be beneficial for the improvement of endothelial dysfunction and associated portal hypertension in patients with cirrhosis. Furthermore, therapeutic agents that are identified in increasing NO bioavailability through improvement of hepatic endothelial nitric oxide synthase (eNOS) activity and reduction in hepatic asymmetric dimethylarginine, an endogenous modulator of eNOS and a key mediator of elevated intrahepatic vascular tone in cirrhosis would be interesting therapeutic approaches in patients with endothelial dysfunction and portal hypertension in advanced liver diseases.

Clinical utility of fixed-dose combinations in hypertension: evidence for the potential of nebivolol/valsartan

Despite significant advances in pharmacologic approaches to treat hypertension during the last decades, hypertension- and hypertension-related organ damage are still a high health and economic burden because a large proportion of patients with hypertension do not achieve optimal blood pressure control. There is now general agreement that combination therapy with two or more antihypertensive drugs is required for targeted blood pressure accomplishment and reduction of global cardiovascular risk. The goals of combination therapies are to reduce long-term cardiovascular events by targeting different mechanism underlying hypertension and target organ disease, to block the counterregulatory pathways activated by monotherapies, to improve tolerability and decrease the adverse effects of up-titrated single agents, and to increase persistence and adherence with antihypertensive therapy. Multiple clinical trials provide evidence that fixed-dose combinations in a single pill offer several advantages when compared with loose-dose combinations. This review discusses the advances in hypertension control and associated cardiovascular disease as they relate to the prospect of combination therapy targeting a third-generation beta (β) 1-adrenergic receptor (nebivolol) and an angiotensin II receptor blocker (valsartan) in fixed-dose single-pill formulations.

Evaluation and management of patients with heart disease and cancer: cardio-oncology

The care for patients with cancer has advanced greatly over the past decades. A combination of earlier cancer diagnosis and greater use of traditional and new systemic treatments has decreased cancer-related mortality. Effective cancer therapies, however, can result in short- and long-term comorbidities that can decrease the net clinical gain by affecting quality of life and survival. In particular, cardiovascular complications of cancer treatments can have a profound effect on the health of patients with cancer and are more common among those with recognized or unrecognized underlying cardiovascular diseases. A new discipline termed cardio-oncology has thus evolved to address the cardiovascular needs of patients with cancer and optimize their care in a multidisciplinary approach. This review provides a brief introduction and background on this emerging field and then focuses on its practical aspects including cardiovascular risk assessment and prevention before cancer treatment, cardiovascular surveillance and therapy during cancer treatment, and cardiovascular monitoring and management after cancer therapy. The content of this review is based on a literature search of PubMed between January 1, 1960, and February 1, 2014, using the search terms cancer, cardiomyopathy, cardiotoxicity, cardio-oncology, chemotherapy, heart failure, and radiation.

Nebivolol: a multifaceted antioxidant and cardioprotectant in hypertensive heart disease

Cardiomyocyte necrosis with attendant microscopic scarring is a pathological feature of human hypertensive heart disease (HHD). Understanding the pathophysiological origins of necrosis is integral to its prevention. In a rat model of HHD associated with aldosterone/salt treatment (ALDOST), myocyte necrosis is attributable to oxidative stress induced by cytosolic-free [Ca]i and mitochondrial [Ca]m overloading in which the rate of reactive oxygen species generation overwhelms their rate of detoxification by endogenous Zn-based antioxidant defenses. We hypothesized that nebivolol (Neb), unlike another β1 adrenergic receptor antagonist atenolol (Aten), would have a multifaceted antioxidant potential based on its dual property as a β3 receptor agonist, which activates endothelial nitric oxide synthase to stimulate nitric oxide (NO) generation. NO promotes the release of cytosolic Zn sequestered inactive by its binding protein, metallothionein. Given the reciprocal regulation between these cations, increased [Zn]i reduces Ca entry and attendant rise in [Ca]i and [Ca]m. Herein, we examined the antioxidant and cardioprotectant properties of Neb and Aten in rats receiving 4 weeks ALDOST. Compared with untreated age-/sex-matched controls, ALDOST alone or ALDOST with Aten, Neb cotreatment induced endothelial nitric oxide synthase activation, NO generation and a marked increase in [Zn]i with associated decline in [Ca]i and [Ca]m. Attendant antioxidant profile at subcellular and cellular levels included attenuation of mitochondrial H2O2 production and lipid peroxidation expressed as reduced 8-isoprostane concentrations in both mitochondria and cardiac tissue. Myocyte salvage was expressed as reduced microscopic scarring and tissue collagen volume fraction. Neb is a multifaceted antioxidant with unique properties as cardioprotectant in HHD.

Identification of bona fide alternative renin transcripts expressed along cortical tubules and potential roles in promoting insulin resistance in vivo without significant plasma renin activity elevation

Renin belongs to a family of aspartyl proteases and is the rate-limiting enzyme in the synthesis of the potent vasoactive peptide angiotensin II. Processing of renal renin has been extensively investigated in juxtaglomerular granular cells, in which prorenin and active renin are present in secretory condensed granules. Previous studies demonstrated alternative renin transcription in rat adrenal glands. Different studies reported novel intracellular forms of renin deduced from novel 5' variants derived from renin mRNA in both mice and humans. Comprehensive detailed studies in genetically engineered mice showed that both a secreted and an intracellular form of renin plays divergent mechanism regulating fluid intake and metabolism by the brain renin-angiotensin system; however, the presence, regulation, and functions of these renin isoforms in kidney and adrenal gland are not fully understood in mice. To investigate the characteristics of renin isoforms in mice, we performed a systematic inventory of renin transcripts of mice with and without a duplication of the renin gene alternatively from previous studies. We discovered a novel isoform of renin of the Ren2 gene, which conserved functionally important residues of the prosegment and incomplete isoforms of the Ren1C/D gene lacking a pre-pro segment. In situ hybridization assays revealed alternative renin isoforms expressed along cortical tubules. Newly generated transgenic mice with systemic overexpression of alternative renin transcript showed enhanced local angiotensin II generation without elevation of plasma renin activity and systemic insulin resistance in vivo, providing new pathophysiological insights into insulin resistance exaggerated by bona fide renin isoform.

Treatment with nebivolol combined with physical training promotes improvements in the cardiovascular responses of hypertensive rats

The aim of this study was to determine whether exercise training combined with beta-blocker treatment promotes additional cardiovascular benefits compared with either intervention on its own. For this we used 76 Wistar rats distributed among different groups: normotensive sedentary (NS), normotensive trained (NT), normotensive sedentary treated with beta-blocker (NS_BB), normotensive trained treated with beta-blocker (NT_BB), hypertensive sedentary (HS), hypertensive trained (HT), hypertensive sedentary treated with a beta-blocker (HS_BB), and hypertensive trained rats treated with beta-blocker (HT_BB). Exercise training consisted of 4 weeks of swimming for 60 min a day, 5 days a week. Hypertension was induced with l-NAME (4 weeks), whereas the control rats received saline, and both the control and test rats received nebivolol. The animals underwent surgery to directly record their blood pressure. The HS group showed higher mean arterial pressure (MAP) (P = 0.000), systolic arterial pressure (P = 0.000), and diastolic arterial pressure (P = 0.000) compared with NS. MAP was higher in the HS compared with the HT (P = 0.002), HS_BB (P = 0.018), and HT_BB (P = 0.015) groups. Hearts from the HS group had a higher percentage of collagen compared with the NS and HS_BB groups. The HT_BB and HT groups only had a higher percentage of cardiac collagen by comparison with the HS_BB group. The HT_BB group showed higher levels of macrophages and neutrophils by comparison with the HT and HS_BB groups. Thus, treatment with a beta-blocker combined with physical training was associated with increased cardiovascular benefits over either intervention alone.

Reactive oxygen species, vascular Noxs, and hypertension: focus on translational and clinical research

SIGNIFICANCE

Reactive oxygen species (ROS) are signaling molecules that are important in physiological processes, including host defense, aging, and cellular homeostasis. Increased ROS bioavailability and altered redox signaling (oxidative stress) have been implicated in the onset and/or progression of chronic diseases, including hypertension.

RECENT ADVANCES

Although oxidative stress may not be the only cause of hypertension, it amplifies blood pressure elevation in the presence of other pro-hypertensive factors, such as salt loading, activation of the renin-angiotensin-aldosterone system, and sympathetic hyperactivity, at least in experimental models. A major source for ROS in the cardiovascular-renal system is a family of nicotinamide adenine dinucleotide phosphate oxidases (Noxs), including the prototypic Nox2-based Nox, and Nox family members: Nox1, Nox4, and Nox5.

CRITICAL ISSUES

Although extensive experimental data support a role for increased ROS levels and altered redox signaling in the pathogenesis of hypertension, the role in clinical hypertension is unclear, as a direct causative role of ROS in blood pressure elevation has yet to be demonstrated in humans. Nevertheless, what is becoming increasingly evident is that abnormal ROS regulation and aberrant signaling through redox-sensitive pathways are important in the pathophysiological processes which is associated with vascular injury and target-organ damage in hypertension.

FUTURE DIRECTIONS

There is a paucity of clinical information related to the mechanisms of oxidative stress and blood pressure elevation, and a few assays accurately measure ROS directly in patients. Such further ROS research is needed in humans and in the development of adequately validated analytical methods to accurately assess oxidative stress in the clinic.

Salt loading exacerbates diastolic dysfunction and cardiac remodeling in young female Ren2 rats

OBJECTIVE

Recent data would suggest pre-menopausal insulin resistant women are more prone to diastolic dysfunction than men, yet it is unclear why. We and others have reported that transgenic (mRen2)27 (Ren2) rats overexpressing the murine renin transgene are insulin resistant due to oxidative stress in insulin sensitive tissues. As increased salt intake promotes inflammation and oxidative stress, we hypothesized that excess dietary salt would promote diastolic dysfunction in transgenic females under conditions of excess tissue Ang II and circulating aldosterone levels.

MATERIALS/METHODS

For this purpose we evaluated cardiac function in young female Ren2 rats or age-matched Sprague-Dawley (SD) littermates exposed to a high (4%) salt or normal rat chow intake for three weeks.

RESULTS

Compared to SD littermates, at 10weeks of age, female Ren2 rats fed normal chow showed elevations in left ventricular (LV) systolic pressures, LV and cardiomyocyte hypertrophy, and displayed reductions in LV initial filling rate accompanied by increases in 3-nitrotyrosine content as a marker of oxidant stress. Following 3weeks of a salt diet, female Ren2 rats exhibited no further changes in LV systolic pressure, insulin resistance, or markers of hypertrophy but exaggerated increases in type 1 collagen, 3-nitrotryosine content, and diastolic dysfunction. These findings occurred in parallel with ultrastructural findings of pericapillary fibrosis, increased LV remodeling, and mitochondrial biogenesis.

CONCLUSION

These data suggest that a diet high in salt in hypertensive female Ren2 rats promotes greater oxidative stress, maladaptive LV remodeling, fibrosis, and associated diastolic dysfunction without further changes in LV systolic pressure or hypertrophy.

The role of Beta-adrenergic receptor blockers in Alzheimer's disease: potential genetic and cellular signaling mechanisms

According to genetic studies, Alzheimer's disease (AD) is linked to beta-adrenergic receptor blockade through numerous factors, including human leukocyte antigen genes, the renin-angiotensin system, poly(adenosine diphosphate-ribose) polymerase 1, nerve growth factor, vascular endothelial growth factor, and the reduced form of nicotinamide adenine dinucleotide phosphate. Beta-adrenergic receptor blockade is also implicated in AD due to its effects on matrix metalloproteinases, mitogen-activated protein kinase pathways, prostaglandins, cyclooxygenase-2, and nitric oxide synthase. Beta-adrenergic receptor blockade may also have a significant role in AD, although the role is controversial. Behavioral symptoms, sex, or genetic factors, including Beta 2-adrenergic receptor variants, apolipoprotein E, and cytochrome P450 CYP2D6, may contribute to beta-adrenergic receptor blockade modulation in AD. Thus, the characterization of beta-adrenergic receptor blockade in patients with AD is needed.

Imidapril inhibits right ventricular remodeling induced by low ambient temperature in broiler chickens

This study explored the effect of imidapril on the right ventricular remodeling induced by low ambient temperature in broiler chickens. Twenty-four broiler chickens were randomly divided into 3 groups (n = 8), including the control group, low temperature group, and imidapril group. Chickens in the control group were raised at normal temperature, whereas chickens in the low temperature group and imidapril group were exposed to low ambient temperature (12 to 18°C) from 14 d of age until 45 d of age. At the same time, chickens in the imidapril group were gavaged with imidapril at 3 mg/kg once daily for 30 d. The thickness of the right ventricular wall was observed with echocardiography. The BW and wet lung weight as well as weight of right and left ventricles and ventricular septum were measured. Both wet lung weight index and right ventricular hypertrophy index were calculated. Pulmonary arterial systolic pressure was assessed according to echocardiography. The expression of ACE and ACE2 mRNA in the right ventricular myocardial tissue was quantified by real-time PCR. Proliferating cell nuclear antigen-positive cells were detected by immunohistostaining. The concentration of angiotensin (Ang) II and Ang (1-7) in the right ventricular myocardial tissue was measured with ELISA. The results showed that right ventricular hypertrophy index, wet lung weight index, pulmonary arterial systolic pressure, expression of ACE mRNA in the right ventricular tissue, Ang II concentration, and the thickness of the right ventricular wall in the low temperature group increased significantly compared with those in the control group and imidapril group. The ACE2 mRNA expression increased 36%, whereas Ang (1-7) concentration decreased significantly in the low temperature group compared with that in the control group and imidapril group. In conclusion, imidapril inhibits right ventricular remodeling induced by low ambient temperature in broiler chickens.

The role of β-adrenergic blockers in Parkinson's disease: possible genetic and cell-signaling mechanisms

Genetic studies have identified numerous factors linking β-adrenergic blockade to Parkinson's disease (PD), including human leukocyte antigen genes, the renin-angiotensin system, poly(adenosine diphosphate-ribose) polymerase 1, nerve growth factor, vascular endothelial growth factor, and the reduced form of nicotinamide adenine dinucleotide phosphate. β-Adrenergic blockade has also been implicated in PD via its effects on matrix metalloproteinases, mitogen-activated protein kinase pathways, prostaglandins, cyclooxygenase 2, and nitric oxide synthase. β-Adrenergic blockade may have a significant role in PD; therefore, the characterization of β-adrenergic blockade in patients with PD is needed.

Gaseous hydrogen sulfide protects against myocardial ischemia-reperfusion injury in mice partially independent from hypometabolism

Background

Ischemia-reperfusion injury (IRI) is a major cause of cardiac damage following various pathological processes. Gaseous hydrogen sulfide (H₂S) is protective during IRI by inducing a hypometabolic state in mice which is associated with anti-apoptotic, anti-inflammatory and antioxidant properties. We investigated whether gaseous H₂S administration is protective in cardiac IRI and whether non-hypometabolic concentrations of H₂S have similar protective properties.

Methods

Male C57BL/6 mice received a 0, 10, or 100 ppm H₂S-N₂ mixture starting 30 minutes prior to ischemia until 5 minutes pre-reperfusion. IRI was inflicted by temporary ligation of the left coronary artery for 30 minutes. High-resolution respirometry equipment was used to assess CO₂-production and blood pressure was measured using internal transmitters. The effects of H₂S were assessed by histological and molecular analysis.

Results

Treatment with 100 ppm H₂S decreased CO₂-production by 72%, blood pressure by 14% and heart rate by 25%, while treatment with 10 ppm H₂S had no effects. At day 1 of reperfusion 10 ppm H₂S showed no effect on necrosis, while treatment with 100 ppm H₂S reduced necrosis by 62% (p<0.05). Seven days post-reperfusion, both 10 ppm (p<0.01) and 100 ppm (p<0.05) H₂S showed a reduction in fibrosis compared to IRI animals. Both 10 ppm and 100 ppm H₂S reduced granulocyte-influx by 43% (p<0.05) and 60% (p<0.001), respectively. At 7 days post-reperfusion both 10 and 100 ppm H₂S reduced expression of fibronectin by 63% (p<0.05) and 67% (p<0.01) and ANP by 84% and 63% (p<0.05), respectively.

Conclusions

Gaseous administration of H₂S is protective when administered during a cardiac ischemic insult. Although hypometabolism is restricted to small animals, we now showed that low non-hypometabolic concentrations of H₂S also have protective properties in IRI. Since IRI is a frequent cause of myocardial damage during percutaneous coronary intervention and cardiac transplantation, H₂S treatment might lead to novel therapeutical modalities.

Differential effects of nebivolol versus metoprolol on functional sympatholysis in hypertensive humans

In young healthy humans, sympathetic vasoconstriction is markedly blunted during exercise to optimize blood flow to the metabolically active muscle. This phenomenon known as functional sympatholysis is impaired in hypertensive humans and rats by angiotensin II-dependent mechanisms, involving oxidative stress and inactivation of nitric oxide (NO). Nebivolol is a β1-adrenergic receptor blocker that has NO-dependent vasodilatory and antioxidant properties. We therefore asked whether nebivolol would restore functional sympatholysis in hypertensive humans. In 21 subjects with stage 1 hypertension, we measured muscle oxygenation and forearm blood flow responses to reflex increases in sympathetic nerve activity evoked by lower body negative pressure at rest, and during rhythmic handgrip exercise at baseline, after 12 weeks of nebivolol (5-20 mg/d) or metoprolol (100-300 mg/d), using a double-blind crossover design. We found that nebivolol had no effect on lower body negative pressure-induced decreases in oxygenation and forearm blood flow in resting forearm (from -29±5% to -30±5% and from -29±3% to -29±3%, respectively; P=NS). However, nebivolol attenuated the lower body negative pressure-induced reduction in oxygenation and forearm blood flow in exercising forearm (from -14±4% to -1±5% and from -15±2% to -6±2%, respectively; both P<0.05). This effect of nebivolol on oxygenation and forearm blood flow in exercising forearm was not observed with metoprolol in the same subjects, despite a similar reduction in blood pressure. Nebivolol had no effect on sympathetic nerve activity at rest or during handgrip, suggesting a direct effect on vascular function. Thus, our data demonstrate that nebivolol restored functional sympatholysis in hypertensive humans by a mechanism that does not involve β1-adrenergic receptors. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT01502787.

The roles of beta-adrenergic receptors in tumorigenesis and the possible use of beta-adrenergic blockers for cancer treatment: possible genetic and cell-signaling mechanisms

Cancer is the leading cause of death in the USA, and the incidence of cancer increases dramatically with age. Beta-adrenergic blockers appear to have a beneficial clinical effect in cancer patients. In this paper, we review the evidence of an association between β-adrenergic blockade and cancer. Genetic studies have provided the opportunity to determine which proteins link β-adrenergic blockade to cancer pathology. In particular, this link involves the major histocompatibility complex class II molecules, the renin-angiotensin system, transcription factor nuclear factor-kappa-light-chain-enhancer of activated B cells, poly(ADP-ribose) polymerase-1, vascular endothelial growth factor, and the reduced form of nicotinamide adenine dinucleotide phosphate oxidase. Beta-adrenergic blockers also exert anticancer effects through non-genomic factors, including matrix metalloproteinase, mitogen-activated protein kinase pathways, prostaglandins, cyclooxygenase-2, oxidative stress, and nitric oxide synthase. In conclusion, β-adrenergic blockade may play a beneficial role in cancer treatment. Additional investigations that examine β-adrenergic blockers as cancer therapeutics are required to further elucidate this role.

Regulation of Overnutrition-Induced Cardiac Inflammatory Mechanisms

BACKGROUND: Unlike conventional β-blockers, nebivolol, a third-generation β-adrenergic receptor blocker with vasodilator properties, promotes insulin sensitivity. Objective: The objective of this study was to determine whether nebivolol regulates overnutrition-induced activation of cardiac nutrient sensor kinases and inflammatory signaling. METHODS: Young Zucker obese (ZO) rats, a rodent model for overnutrition, and age-matched Zucker lean rats were treated with nebivolol (10 mg/kg/day; 21 days) and cardiac function was monitored by echocardiography and pressure volume loop analysis. Activation status of nutrient sensor serine/threonine kinases mammalian target for rapamycin (mTOR), and p70 S6kinase (S6K1) and S6K1-substrate RPS6, inflammatory marker Janus kinase 2 (Jak2) and its substrate STAT1, and energy sensor AMP-dependent kinase (AMPK) were monitored by determining phosphorylation status of pSer(2448) of mTOR, pThr(389) of S6K1, pSer(235/236) of RPS6, pTyr(1007/1008) of Jak2, pTyr(701) of STAT1, and pThr(172) of AMPK, respectively. RESULTS: Nebivolol reduced weight and improved cardiac function of ZO rats as shown by improvements in the myocardial performance index and a decrease in the diastolic parameter tau (τ), the time constant of isovolumic relaxation. Nebivolol also attenuated excessive activation of the nutrient sensor kinases mTOR and S6K1 and their substrate RPS6 as well as the inflammatory marker Jak2 and substrate STAT1 in ZO myocardium (p < 0.05). Moreover, nebivolol reversed suppression of the energy sensor kinase AMPK in ZO hearts (p < 0.05). CONCLUSION: We report for the first time that nebivolol regulates overnutrition-induced activation of cardiac mTOR and Jak/STAT signaling and reverses suppression of AMPK. Since it also suppresses weight gain, nebivolol appears effective in the treatment of overnutrition-related cardiac inflammation and diastolic dysfunction.