Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers for treatment of ischemic heart disease: Future research needs prioritization

Review of the Protective Mechanism of Curcumin on Cardiovascular Disease

Cardiovascular diseases (CVDs) are the most common cause of death worldwide and has been the focus of research in the medical community. Curcumin is a polyphenolic compound extracted from the root of turmeric. Curcumin has been shown to have a variety of pharmacological properties over the past decades. Curcumin can significantly protect cardiomyocyte injury after ischemia and hypoxia, inhibit myocardial hypertrophy and fibrosis, improve ventricular remodeling, reduce drug-induced myocardial injury, improve diabetic cardiomyopathy(DCM), alleviate vascular endothelial dysfunction, inhibit foam cell formation, and reduce vascular smooth muscle cells(VSMCs) proliferation. Clinical studies have shown that curcumin has a protective effect on blood vessels. Toxicological studies have shown that curcumin is safe. But high doses of curcumin also have some side effects, such as liver damage and defects in embryonic heart development. This article reviews the mechanism of curcumin intervention on CVDs in recent years, in order to provide reference for the development of new drugs in the future.

Cardiovascular Protection with a Long-Acting GLP-1 Receptor Agonist Liraglutide: An Experimental Update

Angiotensin II (Ang II), a peptide hormone generated as part of the renin-angiotensin system, has been implicated in the pathophysiology of many cardiovascular diseases such as peripheral artery disease, heart failure, hypertension, coronary artery disease and other conditions. Liraglutide, known as an incretin mimetic, is one of the glucagon-like peptide-1 (GLP-1) receptor agonists, and has been proven to be effective in the treatment of cardiovascular disorders beyond adequate glycemic control. The objective of this review is to compile our recent experimental outcomes-based studies, and provide an overview the cardiovascular protection from liraglutide against Ang II- and pressure overload-mediated deleterious effects on the heart. In particular, the mechanisms of action underlying the inhibition of oxidative stress, vascular endothelial dysfunction, hypertension, cardiac fibrosis, left ventricular hypertrophy and heart failure with liraglutide are addressed. Thus, we support the notion that liraglutide continues to be a useful add-on therapy for the management of cardiovascular diseases.

Anti-fibrotic effects of curcumin and some of its analogues in the heart

Cardiac fibrosis stems from the changes in the expression of fibrotic genes in cardiac fibroblasts (CFs) in response to the tissue damage induced by various cardiovascular diseases (CVDs) leading to their transformation into active myofibroblasts, which produce high amounts of extracellular matrix (ECM) proteins leading, in turn, to excessive deposition of ECM in cardiac tissue. The excessive accumulation of ECM elements causes heart stiffness, tissue scarring, electrical conduction disruption and finally cardiac dysfunction and heart failure. Curcumin (Cur; also known as diferuloylmethane) is a polyphenol compound extracted from rhizomes of Curcuma longa with an influence on an extensive spectrum of biological phenomena including cell proliferation, differentiation, inflammation, pathogenesis, chemoprevention, apoptosis, angiogenesis and cardiac pathological changes. Cumulative evidence has suggested a beneficial role for Cur in improving disrupted cardiac function developed by cardiac fibrosis by establishing a balance between degradation and synthesis of ECM components. There are various molecular mechanisms contributing to the development of cardiac fibrosis. We presented a review of Cur effects on cardiac fibrosis and the discovered underlying mechanisms by them Cur interact to establish its cardio-protective effects.

Future research prioritization in cardiac resynchronization therapy

BACKGROUND

Although cardiac resynchronization therapy (CRT) is effective for some patients with heart failure and a reduced left ventricular ejection fraction (HFrEF), evidence gaps remain for key clinical and policy areas. The objective of the study was to review the data on the effects of CRT for patients with HFrEF receiving pharmacological therapy alone or pharmacological therapy and an implantable cardioverter-defibrillator (ICD) and then, informed by a diverse group of stakeholders, to identify evidence gaps, prioritize them, and develop a research plan.

METHODS

Relevant studies were identified using PubMed and EMBASE and ongoing trials using clinicaltrials.gov. Forced-ranking prioritization method was applied by stakeholders to reach a consensus on the most important questions. Twenty-six stakeholders contributed to the expanded list of evidence gaps, including key investigators from existing randomized controlled trials and others representing different perspectives, including patients, the public, device manufacturers, and policymakers.

RESULTS

Of the 18 top-tier evidence gaps, 8 were related to specific populations or subgroups of interest. Seven were related to the comparative effectiveness and safety of CRT interventions or comparators, and 3 were related to the association of CRT treatment with specific outcomes. The association of comorbidities with CRT effectiveness ranked highest, followed by questions about the effectiveness of CRT among patients with atrial fibrillation and the relationship between gender, QRS morphology and duration, and outcomes for patients either with CRT plus ICD or with ICD.

CONCLUSIONS

Evidence gaps presented in this article highlight numerous, important clinical and policy questions for which there is inconclusive evidence on the role of CRT and provide a framework for future collaborative research.

Liraglutide attenuates cardiac remodeling and improves heart function after abdominal aortic constriction through blocking angiotensin II type 1 receptor in rats

Objective

Angiotensin II (Ang II) is known to contribute to the pathogenesis of heart failure by eliciting cardiac remodeling and dysfunction. The glucagon-like peptide-1 (GLP-1) has been shown to exert cardioprotective effects in animals and patients. This study investigates whether GLP-1 receptor agonist liraglutide inhibits abdominal aortic constriction (AAC)-induced cardiac fibrosis and dysfunction through blocking Ang II type 1 receptor (AT1R) signaling.

Methods

Sprague-Dawley rats were subjected to sham operation and abdominal aortic banding procedure for 16 weeks. In treated rats, liraglutide (0.3 mg/kg) was subcutaneously injected twice daily or telmisartan (10 mg/kg/day), the AT1R blocker, was administered by gastric gavage.

Results

Relative to the animals with AAC, liraglutide reduced protein level of the AT1R and upregulated the AT2R, as evidenced by reduced ratio of AT1R/AT2R (0.59±0.04 vs. 0.91±0.06, p<0.05). Furthermore, the expression of angiotensin converting enzyme 2 was upregulated, tissue levels of malondialdehyde and B-type natriuretic peptide were reduced, and superoxide dismutase activity was increased. Along with a reduction in HW/BW ratio, cardiomyocyte hypertrophy was inhibited. In coincidence with these changes, liraglutide significantly decreased the populations of macrophages and myofibroblasts in the myocardium, which were accompanied by reduced protein levels of transforming growth factor beta1, Smad2/3/4, and upregulated smad7. The synthesis of collagen I and III was inhibited and collagen-rich fibrosis was attenuated. Consistent with these findings, cardiac systolic function was preserved, as shown by increased left ventricular systolic pressure (110±5 vs. 99±2 mmHg, p<0.05), ejection fraction (83%±2% vs. 69%±4%, p<0.05) and fraction shortening (49%±2% vs. 35%±3%, p<0.05). Treatment with telmisartan provided a comparable level of protection as compared with liraglutide in all the parameters measured.

Conclusion

Taken together, liraglutide ameliorates cardiac fibrosis and dysfunction, potentially via suppressing the AT1R-mediated events. These data indicate that liraglutide might be selected as an add-on drug to prevent the progression of heart failure.

Edaravone inhibits pressure overload-induced cardiac fibrosis and dysfunction by reducing expression of angiotensin II AT1 receptor

Angiotensin II (Ang II) is known to be involved in the progression of ventricular dysfunction and heart failure by eliciting cardiac fibrosis. The purpose of this study was to demonstrate whether treatment with an antioxidant compound, edaravone, reduces cardiac fibrosis and improves ventricular function by inhibiting Ang II AT1 receptor. The study was conducted in a rat model of transverse aortic constriction (TAC). In control, rats were subjected to 8 weeks of TAC. In treated rats, edaravone (10 mg/kg/day) or Ang II AT1 receptor blocker, telmisartan (10 mg/kg/day) was administered by intraperitoneal injection or gastric gavage, respectively, during TAC. Relative to the animals with TAC, edaravone reduced myocardial malonaldehyde level and increased superoxide dismutase activity. Protein level of the AT1 receptor was reduced and the AT2 receptor was upregulated, as evidenced by the reduced ratio of AT1 over AT2 receptor (0.57±0.2 vs 3.16±0.39, p<0.05) and less locally expressed AT1 receptor in the myocardium. Furthermore, the protein level of angiotensin converting enzyme 2 was upregulated. In coincidence with these changes, edaravone significantly decreased the populations of macrophages and myofibroblasts in the myocardium, which were accompanied by reduced levels of transforming growth factor beta 1 and Smad2/3. Collagen I synthesis was inhibited and collagen-rich fibrosis was attenuated. Relative to the TAC group, cardiac systolic function was preserved, as shown by increased left ventricular systolic pressure (204±51 vs 110±19 mmHg, p<0.05) and ejection fraction (82%±3% vs 60%±5%, p<0.05). Treatment with telmisartan provided a comparable level of protection as compared with edaravone in all the parameters measured. Taken together, edaravone treatment ameliorates cardiac fibrosis and improves left ventricular function in the pressure overload rat model, potentially via suppressing the AT1 receptor-mediated signaling pathways. These data indicate that edaravone might be selected in combination with other existing drugs in preventing progression of cardiac dysfunction in heart failure.

Postconditioning attenuates coronary perivascular and interstitial fibrosis through modulating angiotensin II receptors and angiotensin-converting enzyme 2 after myocardial infarction

BACKGROUND

Postconditioning (Postcon) is known to reduce infarct size. This study tested the hypothesis that Postcon attenuates the perivascular and interstitial fibrosis after myocardial infarction through modulating angiotensin II-activated fibrotic cascade.

MATERIALS AND METHODS

Male Sprague-Dawley rats were subjected to 45-min coronary occlusion followed by 1 and 6 wk of reperfusion. Postcon was applied at the onset of reperfusion with four cycles of 10/10-s reperfusion-ischemia at the onset of reperfusion. Preconditioning (Precon) with two cycles of 5/5-min ischemia-reperfusion was applied before coronary occlusion.

RESULTS

Postcon reduced angiotensin-converting enzyme protein and expression in the perivascular area and intermyocardium, coincident with the less-expressed angiotensin II receptor, type 1, enhanced angiotensin II receptor, type 2, and angiotensin converting enzyme 2. Postcon lowered the monocyte chemoattractant protein-1 and inhibited the populations of interstitial macrophages (60 ± 12 versus 84 ± 9.5 number per high-powered field [HPF] in control, P < 0.05). Along with these modulations, Postcon also downregulated transforming growth factor β1 protein and inhibited proliferation of α-smooth muscle actin expressing myofibroblasts (41 ± 11 versus 79 ± 8.2 number per HPF in control, P < 0.05), consistent with downregulated phospho-Smad2 and phospho-Smad3. Furthermore, the synthesis of collagen I and III was attenuated, and the perivascular-interstitial fibrosis was inhibited by Postcon as demonstrated by reduced perivascular fibrosis ratio (0.6 ± 0.6 versus 1.6 ± 0.5 per HPF in control, P < 0.05) and smaller collagen-rich area (16 ± 4.7 versus 34 ± 9.2% per HPF in control, P < 0.05). Precon conferred a comparable level of protection as Postcon did in all parameters measured, suggesting protection trigged by this endogenous stimulation can be achieved when it was applied either before ischemia or after reperfusion.

CONCLUSIONS

These results suggest that Postcon could be selected as an adjunctive intervention with other existing therapeutic drugs to treat the fibrosis-derived heart failure patients after myocardial infarction.

Combined statin and angiotensin-converting enzyme (ACE) inhibitor treatment increases the lifespan of long-lived F1 male mice

Statins, such as simvastatin, and ACE inhibitors (ACEis), such as ramipril, are standard therapies for the prevention and treatment of cardiovascular diseases. These types of drugs are commonly administered together. More recently, angiotensin II type 1 receptor (AT1R) antagonists, such as candesartan cilexetil (candesartan), have been used in the place of, or in combination with, ACEis. Here, we investigated the effects of simvastatin and ramipril single and combination therapy, and candesartan treatment on the lifespan of isocalorically fed, long-lived, B6C3F1 mice. Males were used for their relative endocrine simplicity and to minimize animal usage. The drugs were administered daily in food. The simvastatin and ramipril combination therapy significantly increased the mean and median lifespan by 9 %. In contrast, simvastatin, ramipril, or candesartan monotherapy was ineffective. All groups consumed the same number of calories. Simvastatin, alone or administered with ramipril, decreased body weight without changing caloric consumption, suggesting it may alter energy utilization in mice. Combination therapy elevated serum triglyceride and glucose levels, consistent with altered energy homeostasis. Few significant or consistent differences were found in mortality-associated pathologies among the groups. Simvastatin treatment did not reduce normal serum cholesterol or lipid levels in these mice, suggesting that the longevity effects may stem from the pleiotropic, non-cholesterol-related, effects of statins. Together, the results suggest that statins and ACEis together may enhance mouse longevity. Statins and ACE inhibitors are generally well-tolerated, and in combination, they have been shown to increase the lifespan of normotensive, normocholesterolemic humans.

Angiotensin II AT1 receptor alters ACE2 activity, eNOS expression and CD44-hyaluronan interaction in rats with hypertension and myocardial fibrosis

AIM

This study tested the hypothesis that angiotensin II (Ang II) AT1 receptor is involved in development of hypertension and cardiac fibrosis via modifying ACE2 activity, eNOS expression and CD44-hyaluronan interaction.

MAIN METHODS

Male Sprague-Dawley rats were subjected to Ang II infusion (500ng/kg/min) using osmotic minipumps up to 4weeks and the AT1 receptor blocker, telmisartan was administered by gastric gavage (10mg/kg/day) during Ang II infusion.

KEY FINDINGS

Our results indicated that Ang II enhances AT1 receptor, downregulates AT2 receptor, ACE2 activity and eNOS expression, and increases CD44 expression and hyaluronidase activity, an enzyme for hyaluronan degradation. Further analyses revealed that Ang II increases blood pressure and augments vascular/interstitial fibrosis. Comparison of the Ang II group, treatment with telmisartan significantly increased ACE2 activity and eNOS expression in the intracardiac vessels and intermyocardium. These changes occurred in coincidence with decreased blood pressure. Furthermore, the locally-expressed AT1 receptor was downregulated, as evidenced by an increased ratio of the AT2 over AT1 receptor (1.4±0.4% vs. 0.4±0.1% in Ang II group, P<0.05). Along with these modulations, telmisartan inhibited membrane CD44 expression and hyaluronidase activity, decreased populations of macrophages and myofibroblasts, and reduced expression of TGFβ1 and Smads. Collagen I synthesis and tissue fibrosis were attenuated as demonstrated by the less extensive collagen-rich area.

SIGNIFICANCE

These results suggest that the AT1 receptor is involved in development of hypertension and cardiac fibrosis. Selective activating ACE2/eNOS and inhibiting CD44/HA interaction might be considered as the therapeutic targets for attenuating Ang II induced deleterious cardiovascular effects.

Attenuation of myocardial fibrosis with curcumin is mediated by modulating expression of angiotensin II AT1/AT2 receptors and ACE2 in rats

Curcumin is known to improve cardiac function by balancing degradation and synthesis of collagens after myocardial infarction. This study tested the hypothesis that inhibition of myocardial fibrosis by curcumin is associated with modulating expression of angiotensin II (Ang II) receptors and angiotensin-converting enzyme 2 (ACE2). Male Sprague Dawley rats were subjected to Ang II infusion (500 ng/kg/min) using osmotic minipumps for 2 and 4 weeks, respectively, and curcumin (150 mg/kg/day) was fed by gastric gavage during Ang II infusion. Compared to the animals with Ang II infusion, curcumin significantly decreased the mean arterial blood pressure during the course of the observation. The protein level of the Ang II type 1 (AT1) receptor was reduced, and the Ang II type 2 (AT2) receptor was up-regulated, evidenced by an increased ratio of the AT2 receptor over the AT1 receptor in the curcumin group (1.2±0.02%) vs in the Ang II group (0.7±0.03%, P<0.05). These changes were coincident with less locally expressed AT1 receptor and enhanced AT2 receptor in the intracardiac vessels and intermyocardium. Along with these modulations, curcumin significantly decreased the populations of macrophages and alpha smooth muscle actin-expressing myofibroblasts, which were accompanied by reduced expression of transforming growth factor beta 1 and phosphorylated-Smad2/3. Collagen I synthesis was inhibited, and tissue fibrosis was attenuated, as demonstrated by less extensive collagen-rich fibrosis. Furthermore, curcumin increased protein level of ACE2 and enhanced its expression in the intermyocardium relative to the Ang II group. These results suggest that curcumin could be considered as an add-on therapeutic agent in the treatment of fibrosis-derived heart failure patient who is intolerant of ACE inhibitor therapy.

Interventions to Slow Aging in Humans: Are We Ready?

The workshop entitled ‘Interventions to Slow Aging in Humans: Are We Ready?’ was held in Erice, Italy, on October 8–13, 2013, to bring together leading experts in the biology and genetics of aging and obtain a consensus related to the discovery and development of safe interventions to slow aging and increase healthy lifespan in humans. There was consensus that there is sufficient evidence that aging interventions will delay and prevent disease onset for many chronic conditions of adult and old age. Essential pathways have been identified, and behavioral, dietary, and pharmacologic approaches have emerged. Although many gene targets and drugs were discussed and there was not complete consensus about all interventions, the participants selected a subset of the most promising strategies that could be tested in humans for their effects on healthspan. These were: (i) dietary interventions mimicking chronic dietary restriction (periodic fasting mimicking diets, protein restriction, etc.); (ii) drugs that inhibit the growth hormone/IGF-I axis; (iii) drugs that inhibit the mTOR–S6K pathway; or (iv) drugs that activate AMPK or specific sirtuins. These choices were based in part on consistent evidence for the pro-longevity effects and ability of these interventions to prevent or delay multiple age-related diseases and improve healthspan in simple model organisms and rodents and their potential to be safe and effective in extending human healthspan. The authors of this manuscript were speakers and discussants invited to the workshop. The following summary highlights the major points addressed and the conclusions of the meeting.

Mapping the extracellular and membrane proteome associated with the vasculature and the stroma in the embryo

In order to map the extracellular or membrane proteome associated with the vasculature and the stroma in an embryonic organism in vivo, we developed a biotinylation technique for chicken embryo and combined it with mass spectrometry and bioinformatic analysis. We also applied this procedure to implanted tumors growing on the chorioallantoic membrane or after the induction of granulation tissue. Membrane and extracellular matrix proteins were the most abundant components identified. Relative quantitative analysis revealed differential protein expression patterns in several tissues. Through a bioinformatic approach, we determined endothelial cell protein expression signatures, which allowed us to identify several proteins not yet reported to be associated with endothelial cells or the vasculature. This is the first study reported so far that applies in vivo biotinylation, in combination with robust label-free quantitative proteomics approaches and bioinformatic analysis, to an embryonic organism. It also provides the first description of the vascular and matrix proteome of the embryo that might constitute the starting point for further developments.