Alpha-lipoic acid enhances ischemic postconditioning-mediated improvement of myocardial infarction and apoptosis in diabetic rats with ischemia/reperfusion injury

This work evaluated the combined effects of alpha-lipoic acid (ALA) and ischemic postconditioning (Post) on myocardial infarction and cell death in rats with chronic type-II diabetes following ischemia/reperfusion injury. The rats received a high-fat diet and were given one intraperitoneal injection of 35 mg/kg streptozotocin to induce chronic diabetes. They were then pretreated with ALA (100 mg/kg/day, orally) for 5 weeks before undergoing ischemia/reperfusion (I/R) insult. The hearts experienced 35 min regional ischemia through ligating the left anterior descending coronary artery, followed by 60 min reperfusion. The Post protocol involved 6 cycles of a 10/10 s algorithm, applied during the early stage of reperfusion. The use of Post alone did not significantly alter lactate dehydrogenase and infarct size levels, while ALA showed positive effects. Similar findings were observed for apoptotic changes with single treatments. However, the concurrent administration of ALA and Post significantly reduced the protein expressions of Bax, Bax/Bcl2, and cleaved caspase-3 while increasing Bcl2 expression. Additionally, the histopathological findings of the combined therapy were superior to those of single treatments. The concomitant use of ALA and Post effectively inhibited apoptosis, leading to cardiac recovery after I/R injury in diabetic conditions. This strategy could improve outcomes for preserving diabetic hearts following I/R insults.

Keeping the Heart Healthy: The Role of Exercise in Cardiac Repair and Regeneration

Significance: Heart failure is often accompanied by a decrease in the number of cardiomyocytes. Although the adult mammalian hearts have limited regenerative capacity, the rate of regeneration is extremely low and decreases with age. Exercise is an effective means to improve cardiovascular function and prevent cardiovascular diseases. However, the molecular mechanisms of how exercise acts on cardiomyocytes are still not fully elucidated. Therefore, it is important to explore the role of exercise in cardiomyocytes and cardiac regeneration. Recent Advances: Recent advances have shown that the effects of exercise on cardiomyocytes are critical for cardiac repair and regeneration. Exercise can induce cardiomyocyte growth by increasing the size and number. It can induce physiological cardiomyocyte hypertrophy, inhibit cardiomyocyte apoptosis, and promote cardiomyocyte proliferation. In this review, we have discussed the molecular mechanisms and recent studies of exercise-induced cardiac regeneration, with a focus on its effects on cardiomyocytes. Critical Issues: There is no effective way to promote cardiac regeneration. Moderate exercise can keep the heart healthy by encouraging adult cardiomyocytes to survive and regenerate. Therefore, exercise could be a promising tool for stimulating the regenerative capability of the heart and keeping the heart healthy. Future Directions: Although exercise is an important measure to promote cardiomyocyte growth and subsequent cardiac regeneration, more studies are needed on how to do beneficial exercise and what factors are involved in cardiac repair and regeneration. Thus, it is important to clarify the mechanisms, pathways, and other critical factors involved in the exercise-mediated cardiac repair and regeneration. Antioxid. Redox Signal. 39, 1088-1107.

Renin-Angiotensin System: Updated Understanding and Role in Physiological and Pathophysiological States

The classical view of the renin-angiotensin system (RAS) is that of the circulating hormone pathway involved in salt and water homeostasis and blood pressure regulation. It is also involved in the pathogenesis of cardiac and renal disorders. This led to the creation of drugs blocking the actions of this classical pathway, which improved cardiac and renal outcomes. Our understanding of the RAS has significantly expanded with the discovery of new peptides involved in this complex pathway. Over the last two decades, a counter-regulatory or protective pathway has been discovered that opposes the effects of the classical pathway. Components of RAS are also implicated in the pathogenesis of obesity and its metabolic diseases. The continued discovery of newer molecules also provides novel therapeutic targets to improve disease outcomes. This article aims to provide an overview of an updated understanding of the RAS, its role in physiological and pathological processes, and potential novel therapeutic options from RAS for managing cardiorenal disorders, obesity, and related metabolic disorders.

Purification, Structural Analysis and Cardio-Protective Activity of Polysaccharides from Radix Astragali

Two polysaccharides, named APS2-I and APS3-I, were purified from the water extract of Radix Astragali. The average molecular weight of APS2-I was 1.96 × 10⁶ Da and composed of Man, Rha, GlcA, GalA, Glc, Gal, Xyl, and Ara in a molar ratio of 2.3:4.8:1.7:14.0:5.8:11.7:2.8:12.6, while the average molecular weight of APS3-I was 3.91 × 10⁶ Da and composed of Rha, GalA, Glc, Gal, and Ara in a molar ratio of 0.8:2.3:0.8:2.3:4.1. Biological evaluation showed APS2-I and APS3-I had significant antioxidant activity and myocardial protection activity. Furthermore, total polysaccharide treatment could significantly enhance hemodynamic parameters and improve cardiac function in rat ischemia and reperfusion isolated heart models. These results provided important information for the clinical application of APS in the field of cardiovascular disease and implied that Astragalus polysaccharides (APS) could be considered as a reference for the quality control of Radix Astragali.

Cardio-Protective Role of a Gut Hormone Obestatin: A Narrative Review

Obestatin is a gut hormone composed of 23 amino acids that play a role in protecting the heart. It is synthesized from the same preproghrelin gut hormone gene as another gut hormone. The function and receptor of obestatin remain controversial, despite being present in various organs such as the liver, heart, mammary gland, pancreas, and more. The activity of obestatin is opposite to that of ghrelin, another hormone. The GPR-39 receptor is used by obestatin to exert its effects. Obestatin's cardioprotective role can be attributed to its ability to affect various factors, including adipose tissue, blood pressure regulation, heart, ischemia-reperfusion injury, endothelial cells, and diabetes. Because these factors are related to the cardiovascular system, modifying them via obestatin can provide cardioprotection. Furthermore, ghrelin, its antagonist hormone, regulates cardiovascular health. Diabetes mellitus, hypertension, and ischemia-reperfusion injury can all alter ghrelin/obestatin levels. Obestatin has also been shown to impact other organs, reducing weight and appetite, inhibiting food intake, and increasing adipogenesis. Obestatin has a brief half-life and is quickly degraded by proteases in the blood, liver, and kidneys after entering circulation. This article offers insights into the cardiac function of obestatin.

Effect of phosphodiesterase type 5 inhibitors on major adverse cardiovascular events and overall mortality in a large nationwide cohort of men with erectile dysfunction and cardiovascular risk factors: A retrospective, observational study based on healthcare claims and national death index data

BACKGROUND

Treatment with phosphodiesterase type 5 inhibitors (PDE-5is) is effective in treating erectile dysfunction (ED).

AIM

The objective of this study was to determine the effect of PDE-5is on the incidence of major adverse cardiovascular (CV) events (MACE; composite outcome of CV death, hospitalization for myocardial infarction, coronary revascularization, stroke, heart failure, and unstable angina pectoris) and overall mortality.

METHODS

A retrospective observational cohort study was conducted in a large US claims database in men with ≥1 diagnosis of ED without prior MACE within 1 year, from January 1, 2006, to October 31, 2020. The exposed group had ≥1 claim for PDE-5i and the unexposed group had no claims for PDE-5i, and the groups were matched up to 1:4 on baseline risk variables.

OUTCOME

The primary outcome was MACE and the secondary outcomes were overall mortality and individual components of MACE, determined by multivariable Cox proportional hazard modeling.

RESULTS

Matched plus multivariable analyses showed that MACE was lower by 13% in men exposed (n = 23 816) to PDE-5is (hazard ratio [HR] 0.87; 95% CI 0.79-0.95; P = .001) vs nonexposure (n = 48 682) over mean follow-up periods of 37 and 29 months, respectively, with lower incidence of coronary revascularization (HR 0.85; 95% CI 0.73-0.98; P = .029), heart failure (HR 0.83; 95% CI 0.72-0.97; P = .016), unstable angina (HR 0.78; 95% CI 0.64-0.96; P = .021), and CV death (HR 0.61; 95% CI 0.41-0.90; P = .014) with PDE-5i exposure. Phosphodiesterase type 5 inhibitor-exposed men had a 25% lower incidence of overall mortality (HR 0.75; 95% CI 0.65-0.87; P < .001). Men without coronary artery disease (CAD) but with CV risk factors at baseline showed a similar pattern. In the main study cohort, men in the highest quartile of PDE-5i exposure had the lowest incidence of MACE (HR 0.45; 95% CI 0.37-0.54; P < .001) and overall mortality (HR 0.51; 95% CI 0.37-0.71; P < .001) vs the lowest exposure quartile. In a subgroup with baseline type 2 diabetes (n = 6503), PDE-5i exposure was associated with a lower MACE risk (HR 0.79; 95% CI 0.64-0.97; P = .022).

CLINICAL IMPLICATIONS

PDE-5is may have cardioprotective effects.

STRENGTHS AND LIMITATIONS

Strengths are the large numbers of participants and consistency of the data; limitations include the retrospective nature of the study and unknown confounders.

CONCLUSIONS

In a large population of US men with ED, PDE-5i exposure was associated with lower incidence of MACE, CV death, and overall mortality risk compared to non-exposure. Risk reduction correlated with PDE-5i exposure level.

Poly(I:C) attenuates myocardial ischemia/reperfusion injury by restoring autophagic function

Polyinosinic-polycytidylic acid (poly(I:C)) is the agonist of Toll-like receptor 3 (TLR3), which participates in innate immune responses under the condition of myocardial ischemia/reperfusion injury (MIRI). It has been shown that poly(I:C) exhibited cardioprotective activities through the PI3K/Akt pathway, which is the main signal transduction pathway during autophagy. However, the precise mechanism by whether poly(I:C) regulates autophagy remains poorly understood. Thus, this study was designed to investigate the therapeutic effect of poly(I:C) against MIRI and the underlying pathway connection with autophagy. We demonstrated that 1.25 and 5 mg/kg poly(I:C) preconditioning significantly reduced myocardial infarct size and cardiac dysfunction. Moreover, poly(I:C) significantly promoted cell survival by restoring autophagy flux and then regulating it to an adequate level Increased autophagy protein Beclin1 and LC3II together with p62 degradation after additional chloroquine. In addition, mRFP-GFP-LC3 adenoviruses exhibited autophagy activity in neonatal rat cardiac myocytes (NRCMs). Mechanistically, poly(I:C) activated the PI3K/AKT/mTOR pathway to induce autophagy, which was abolished by LY294002 (PI3K antagonist), rapamycin (autophagy activator and mTOR inhibitor), or 3-methyladenine (autophagy inhibitor), suggesting either inhibition of the PI3K/Akt/mTOR pathway or autophagy activity interrupt the beneficial effect of poly(I:C) preconditioning. In conclusion, poly(I:C) promotes cardiomyocyte survival from ischemia/reperfusion injury by regulating autophagy via the PI3K/Akt/mTOR pathway.

Cardioprotective effects of alantolactone on isoproterenol-induced cardiac injury and cobalt chloride-induced cardiomyocyte injury

OBJECTIVES

Alantolactone (AL) is a compound extracted from the roots of Inula Racemosa that has shown beneficial effects in cardiovascular disease. However, the cardioprotective mechanism of AL against hypoxic/ischemic (H/I) injury is still unclear. This research aimed to determine AL's ability to protect the heart against isoproterenol (ISO)-induced MI injury in vivo and cobalt chloride (CoCl2) induced H/I injury in vitro.

METHODS

Electrocardiography (ECG), lactate dehydrogenase (LDH), creatine kinase (CK), and cardiac troponin I (cTnI) assays in addition to histological analysis of the myocardium were used to investigate the effects of AL in vivo. Influences of AL on L-type Ca2+ current (ICa-L) in isolated rat myocytes were observed by the patch-clamp technique. Furthermore, cell viability, apoptosis, oxidative stress injury, mitochondrial membrane potential, and intracellular Ca2+ concentration were examined in vitro.

RESULTS

The results indicated that AL treatment ameliorated the morphological and ECG changes associated with MI, and decreased levels of LDH, CK, and cTnI. Furthermore, pretreatment with AL elevated antioxidant enzyme activity and suppressed ROS production. AL prevented H/I-induced apoptosis, mitochondria damage, and calcium overload while reducing ICa-L in a concentration and time dependent fashion. The 50% inhibiting concentration (IC50) and maximal inhibitory effect (Emax) of AL were 17.29 μmol/L and 57.73 ± 1.05%, respectively.

CONCLUSION

AL attenuated MI-related injury by reducing oxidative stress, apoptosis, calcium overload, and mitochondria damage. These cardioprotective effects may be related to the direct inhibition of ICa-L.

Phosphatidylserine Supplementation as a Novel Strategy for Reducing Myocardial Infarct Size and Preventing Adverse Left Ventricular Remodeling

Phosphatidylserines are known to sustain skeletal muscle activity during intense activity or hypoxic conditions, as well as preserve neurocognitive function in older patients. Our previous studies pointed out a potential cardioprotective role of phosphatidylserine in heart ischemia. Therefore, we investigated the effects of phosphatidylserine oral supplementation in a mouse model of acute myocardial infarction (AMI). We found out that phosphatidylserine increases, significantly, the cardiomyocyte survival by 50% in an acute model of myocardial ischemia-reperfusion. Similar, phosphatidylserine reduced significantly the infarcted size by 30% and improved heart function by 25% in a chronic model of AMI. The main responsible mechanism seems to be up-regulation of protein kinase C epsilon (PKC-ε), the main player of cardio-protection during pre-conditioning. Interestingly, if the phosphatidylserine supplementation is started before induction of AMI, but not after, it selectively inhibits neutrophil's activation, such as Interleukin 1 beta (IL-1β) expression, without affecting the healing and fibrosis. Thus, phosphatidylserine supplementation may represent a simple way to activate a pre-conditioning mechanism and may be a promising novel strategy to reduce infarct size following AMI and to prevent myocardial injury during myocardial infarction or cardiac surgery. Due to the minimal adverse effects, further investigation in large animals or in human are soon possible to establish the exact role of phosphatidylserine in cardiac diseases.

Unexpected Pleiotropic Effects of SGLT2 Inhibitors: Pearls and Pitfalls of This Novel Antidiabetic Class

Sodium-glucose co-transporter 2 (SGLT2) inhibitors facilitate urine glucose excretion by reducing glucose reabsorption, leading to ameliorate glycemic control. While the main characteristics of type 2 diabetes mellitus are insufficient insulin secretion and insulin resistance, SGLT2 inhibitors have some favorable effects on pancreatic β-cell function and insulin sensitivity. SGLT2 inhibitors ameliorate fatty liver and reduce visceral fat mass. Furthermore, it has been noted that SGLT2 inhibitors have cardio-protective and renal protective effects in addition to their glucose-lowering effect. In addition, several kinds of SGLT2 inhibitors are used in patients with type 1 diabetes mellitus as an adjuvant therapy to insulin. Taken together, SGLT2 inhibitors have amazing multifaceted effects that are far beyond prediction like some emerging magical medicine. Thereby, SGLT2 inhibitors are very promising as relatively new anti-diabetic drugs and are being paid attention in various aspects. It is noted, however, that SGLT2 inhibitors have several side effects such as urinary tract infection or genital infection. In addition, we should bear in mind the possibility of diabetic ketoacidosis, especially when we use SGLT2 inhibitors in patients with poor insulin secretory capacity.

Cardiac Connexin-43 Hemichannels and Pannexin1 Channels: Provocative Antiarrhythmic Targets

Cardiac connexin-43 (Cx43) creates gap junction channels (GJCs) at intercellular contacts and hemi-channels (HCs) at the peri-junctional plasma membrane and sarcolemmal caveolae/rafts compartments. GJCs are fundamental for the direct cardiac cell-to-cell transmission of electrical and molecular signals which ensures synchronous myocardial contraction. The HCs and structurally similar pannexin1 (Panx1) channels are active in stressful conditions. These channels are essential for paracrine and autocrine communication through the release of ions and signaling molecules to the extracellular environment, or for uptake from it. The HCs and Panx1 channel-opening profoundly affects intracellular ionic homeostasis and redox status and facilitates via purinergic signaling pro-inflammatory and pro-fibrotic processes. These conditions promote cardiac arrhythmogenesis due to the impairment of the GJCs and selective ion channel function. Crosstalk between GJCs and HCs/Panx1 channels could be crucial in the development of arrhythmogenic substrates, including fibrosis. Despite the knowledge gap in the regulation of these channels, current evidence indicates that HCs and Panx1 channel activation can enhance the risk of cardiac arrhythmias. It is extremely challenging to target HCs and Panx1 channels by inhibitory agents to hamper development of cardiac rhythm disorders. Progress in this field may contribute to novel therapeutic approaches for patients prone to develop atrial or ventricular fibrillation.

A novel dipeptide from potato protein hydrolysate augments the effects of exercise training against high-fat diet-induced damages in senescence-accelerated mouse-prone 8 by boosting pAMPK / SIRT1/ PGC-1α/ pFOXO3 pathway

The pathological effects of obesity are often severe in aging condition. Although exercise training is found to be advantageous, the intensity of exercise performed is limited in aging condition. Therefore in this study we assessed the effect of a combined treatment regimen with a short-peptide IF isolated from alcalase potato-protein hydrolysates and a moderate exercise training for 15 weeks in a 6 month old HFD induced obese senescence accelerated mouse-prone 8 (SAMP8) mice model. Animals were divided into 6 groups (n=6) (C:Control+BSA); (HF:HFD+BSA); (EX:Control+ BSA+Exercise); (HF+IF:HFD+ IF); (HF+EX:HFD+Exercise); (HF+EX+IF:HFD+Exercise+IF). A moderate incremental swimming exercise training was provided for 6 weeks and after 3 weeks of exercise, IF was orally administered (1 mg/kg body Weight). The results show that combined administration of IF and exercise provides a better protection to aging animals by reducing body weight and regulated tissue damage. IF intake and exercise training provided protection against cardiac hypertrophy and maintains the tissue homeostasis in the heart and liver sections. Interestingly, IF and exercise training showed an effective upregulation in pAMPK/ SIRT1/ PGC-1α/ pFOXO3 mechanism of cellular longevity. Therefore, exercise training with IF intake is a possible strategy for anti-obesity benefits and superior cardiac and hepatic protection in aging condition.

Cardiovascular Modulating Effects of Magnolol and Honokiol, Two Polyphenolic Compounds from Traditional Chinese Medicine-Magnolia Officinalis

Honokiol and its isomer magnolol are poly-phenolic compounds isolated from the Magnolia officinalis that exert cardiovascular modulating effects via a variety of mechanisms. They are used as blood-quickening and stasis-dispelling agents in Traditional Chinese Medicine and confirmed to have therapeutic potential in atherosclerosis, thrombosis, hypertension, and cardiac hypertrophy. This comprehensive review summarizes the current data regarding the cardioprotective mechanisms of those compounds and identifies areas for further research.

Transplantation of hMSCs Genome Edited with LEF1 Improves Cardio-Protective Effects in Myocardial Infarction. Mol Ther Nucleic Acids. 2020;19:1186-1197. [PMID: 32069701 PMCID: PMC7019046 DOI: 10.1016/j.omtn.2020.01.007]

Stem cell-based therapy is one of the most attractive approaches to ischemic heart diseases, such as myocardial infarction (MI). We evaluated the cardio-protective effects of the human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) stably expressing lymphoid enhancer-binding factor 1 (LEF1; LEF1/hUCB-MSCs) in a rat model of MI. LEF1 overexpression in hUCB-MSCs promoted cell-proliferation and anti-apoptotic effects in hypoxic conditions. For the application of its therapeutic effects in vivo, the LEF1 gene was introduced into an adeno-associated virus integration site 1 (AAVS1) locus, known as a safe harbor site on chromosome 19 by CRISPR/Cas9-mediated gene integration in hUCB-MSCs. Transplantation of LEF1/hUCB-MSCs onto the infarction region in the rat model significantly improved overall survival. The cardio-protective effect of LEF1/hUCB-MSCs was proven by echocardiogram parameters, including greatly improved left-ventricle ejection fraction (EF) and fractional shortening (FS). Moreover, histology and immunohistochemistry successfully presented reduced MI region and fibrosis by LEF1/hUCB-MSCs. We found that these overall positive effects of LEF1/hUCB-MSCs are attributed by increased proliferation and survival of stem cells in oxidative stress conditions and by the secretion of various growth factors by LEF1. In conclusion, this study suggests that the stem cell-based therapy, conjugated with genome editing of transcription factor LEF1, which promotes cell survival, could be an effective therapeutic strategy for cardiovascular disease.

Antioxidant and Anti-Inflammatory Effects of Curcumin Nanoparticles on Drug-Induced Acute Myocardial Infarction in Diabetic Rats

We have investigated the cardio-protective effects of pretreatment with curcumin nanoparticles (CUN) compared to conventional curcumin (CUS) on the changes in oxidative stress parameters and inflammatory cytokine levels during induced acute myocardial infarction (AMI) in rats with diabetes mellitus (DM). DM was induced with streptozotocin, and AMI with isoproterenol. Eight groups of seven Wister Bratislava rats were included in the study. The N-C was the normal control group, AMI-C was the group with AMI, DM-C was the group with DM, and DM-AMI-C was the group with DM and AMI. All four groups received saline solution orally during the whole experiment. S-DM-CUS-AMI and S-DM-CUN-AMI groups received saline for seven days prior to DM induction and continued with CUS (200 mg/kg bw, bw = body weight) for S-DM-CUS-AMI and CUN for S-DM-CUN-AMI (200 mg/kg bw) for 15 days before AMI induction. The CUS-DM-CUS-AMI group received CUS (200 mg/kg bw), while the CUN-DM-CUN-AMI received CUN (200 mg/kg bw) for seven days prior to DM induction, and both groups continued with administration in the same doses for 15 days before AMI induction. CUS and CUN prevented elevation of creatine kinase, creatine kinase-MB, lactate dehydrogenase in all groups, with better results in the CUN (S-DM-CUN-AMI and CUN-DM-CUN-AMI groups). CUS and CUN significantly reduced serum levels of oxidative stress markers (malondialdehyde, the indirect assessment of nitric oxide synthesis, and total oxidative status) and enhanced antioxidative markers (total antioxidative capacity and thiols, up to 2.5 times). All groups that received CUS or CUN showed significantly lower serum levels of tumor necrosis factor-alpha, interleukin-6, and interleukin-1β. The best antioxidative and anti-inflammatory effects were obtained for the group that received CUN before DM induction (CUN-DM-CUN-AMI group). Pretreatment with CUN proved higher cardio-protective effects exerting an important antioxidative and anti-inflammatory impact in the case of AMI in DM.

Associations of vigorous physical activity with all-cause, cardiovascular and cancer mortality among 64 913 adults

Background

Physical activity recommendations state that for the same energy expenditure, moderate-to-vigorous physical activities (MVPAs) produce similar health benefits. However, few epidemiological studies have tested this hypothesis.

Design

We examined whether, compared with moderate, vigorous activity was associated with larger mortality risk reductions.

Methods

Data from 11 cohorts of the Health Survey for England and the Scottish Health Survey, collected from 1994 to 2011 (mean (SD) follow-up, 9.0 (3.6) years). Adults aged ≥30 years reported MVPA and linkage to mortality records. Exposure was the proportion of self-reported weighted MVPA through vigorous activity. Outcomes were all-cause, cardiovascular disease (CVD) and cancer mortality.

Results

Among 64 913 adult respondents (44% men, 56% women, mean (SD) age, 49.8 (13.6) years), there were 5064 deaths from all-causes, 1393 from CVD and 1602 from cancer during 435 743 person-years of follow-up. Compared with those who reported no vigorous physical activity, and holding constant the volume of weighted MVPA, vigorous activity was associated with additional reductions in mortality risk. For all-cause mortality, the adjusted HR was HR=0.84 (95% CI 0.71, 0.99) and HR=0.84 (95% CI 0.76, 0.94) among those who reported between >0% and<30%, or ≥30% of their activity as vigorous, respectively. For CVD and cancer mortality, point estimates showed similar beneficial associations yet CIs were wider and crossed unity.

Conclusion

Vigorous activities were associated with larger reductions in mortality risk than activities of moderate intensity, but no evidence of dose–response effects was found.

Luteolin: A Flavonoid that Has Multiple Cardio-Protective Effects and Its Molecular Mechanisms

Cardiovascular disease (CVD) has become the leading cause of morbidity and mortality worldwide. A well-monitored diet with a sufficient intake of fruits and vegetables has been confirmed as a primary prevention of CVD. Plant constituents such as flavonoids have been shown to confer healthy benefits. Luteolin (Lut), a kind of flavonoid, possesses anti-oxidative, anti-tumor, and anti-inflammatory properties. Recent scientific literature has reported the cardiac protective effects of Lut in vitro and in vivo. Therefore, the aim of this review is to provide an update and detailed overview with cardio-protective molecular mechanisms of Lut with a focus on multiple intrinsic and extrinsic effectors. We further explore how these mechanisms participate in ischemia/reperfusion (I/R) injury, heart failure (HF) and atherosclerosis (AS). A proper understanding of the cardiovascular protective effects and the relative mechanisms of Lut may provide the possibility of new drug design and development for CVD. With the previous studies mainly focused on basic research, we need to advance the prospects of its further clinical utilization against CVD, large prospective clinical trials of Lut are needed to observe its therapeutic effects on patients with I/R injury, HF and AS, especially on the effective therapeutic dosage, and safety of long-term administration.

Rosmarinic Acid Protects against Inflammation and Cardiomyocyte Apoptosis during Myocardial Ischemia/Reperfusion Injury by Activating Peroxisome Proliferator-Activated Receptor Gamma

The cardiac ischemia-reperfusion (I/R) injury greatly influences the therapeutic effect and remains an urgent challenge in clinical therapy. Polypharmacology opens a new therapeutic opportunity to design drugs with a specific target for improving the efficacy. In this study, we first forecasted that Rosmarinic acid (RosA) could be used for the treatment of cardiovascular disease using text mining, chemometric and chemogenomic methods. Consistent with the effect of the positive drug (pioglitazone, PIO), we subsequently validated that RosA pretreatment could restore the decreased cardiac hemodynamic parameters (LVDP, ± dp/dt_min, ± dp/dt_max and CF), decreased the infarct size and the cardiomyocyte apoptosis in a rat model of cardiac I/R injury. Furthermore, RosA pre-treatment inhibited the levels of inflammatory cytokines (IL-6, TNF-α and CRP), up-regulated PPARγ expression and down-regulated NF-κB expression in myocardial tissue isolated from the rat model of I/R-induced myocardial injury. In addition, the effects of RosA were reversed by co-treatment with PPAR-γ inhibitor GW9662 and T0070907, respectively. These data suggest that RosA attenuates cardiac injury through activating PPARγ and down-regulating NF-κB-mediated signaling pathway, which inhibiting inflammation and cardiomyocyte apoptosis in a rat model of cardiac I/R injury.

Minocycline: a bacteriostatic antibiotic with pleiotropic cardioprotective effects

Minocycline belongs to the family of tetracyclines, which are drugs traditionally approved as antibiotics. Based on preclinical animal cardiac models and clinical neurology trials, this drug has gained special attention as a promising cardiovascular therapeutic agent given its anti-inflammatory, antiapoptotic, antioxidant, and antienzymatic properties. This review focuses on the available evidence for minocycline as a cardioprotective drug, with special attention to mechanisms of action. Ongoing cardiovascular clinical trials are briefly discussed.

Non-genomic effects of spironolactone and eplerenone in cardiomyocytes of neonatal Wistar rats: do they evoke cardioprotective pathways?

Mineralocorticoid receptor (MR) antagonists of aldosterone (spironolactone and eplerenone) display beneficial effects in the treatment of cardiopathies; however, many of these responses are independent of this antagonism. The mechanisms of action of these drugs are not well known; few studies have comparatively evaluated whether eplerenone as well as spironolactone display cardioprotective effects independent of the blockade of aldosterone. To study these mechanisms, which lead to cardioprotective responses, and to evaluate comparatively their effects in vitro, we have evaluated the proliferative effect of spironolactone and eplerenone in primary culture of cardiomyocytes and fibroblasts of neonatal Wistar rats in the presence and absence of aldosterone. Spironolactone and eplerenone promoted proliferation of cardiomyocyte even in the absence of aldosterone, suggesting a signaling pathway independent of the antagonism over aldosterone. Spironolactone was able to reduce the proliferation of fibroblasts and to reverse the proliferation promoted by aldosterone, which was also displayed by eplerenone. To elucidate the biochemical pathways evoked by these drugs, we sought to analyze Ca(2+), cAMP, and cGMP, and the activity of PKC and ERK1/2. Spironolactone and eplerenone increased the levels of Ca(2+), cGMP and activity of ERK 1/2, and reversed the action of aldosterone on the activity of PKC and ERK1/2. Interestingly, only spironolactone increased the levels of cAMP. Our data support the fact that in addition to aldosterone, both spironolactone and eplerenone display rapid responses (non-genomic) such as an increase on cAMP, Ca(2+), and cGMP by spironolactone, and Ca(2+) and cGMP by eplerenone. We have observed a more consistent cardioprotection promoted by spironolactone; however, these effects have yet to be tested clinically. Therefore, our data show that these drugs do not only act as an antagonist of MR, but could lead to a new pharmacological classification of these drugs.

Adiponectin expression and the cardioprotective role of the vitamin D receptor activator paricalcitol and the angiotensin converting enzyme inhibitor enalapril in ApoE-deficient mice

BACKGROUND

Coronary heart disease (CHD) is the number one cause of death in the US. The adipokine adiponectin has been studied intensively for presenting and inversed association with almost every stage of CHD. For instance, the evaluation of molecules capable of enhancing endogenous adiponectin expression is well justified. In this study, we investigated the effect of the vitamin D receptor activator (VDRA) paricalcitol and the angiotensin-converting enzyme inhibitor (ACEI) enalapril on adiponectin expression, lipid profiles, adenosine monophosphate activated protein kinase (AMPK) expression, monocyte chemo-attractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNFα),cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), antioxidant capacity, CuZn-superoxide dismutase (CuZn-SOD), Mn-SOD, NADPH p22phox subunits, inducible nitric oxidesynthase (iNOS), endothelial marker eNOS, and 81 atherosclerosis-related genes in ApoE-deficient mice.

METHOD

Seven-week-old ApoE-deficient mice were treated for 16 weeks as follows: Group 1, ApoE vehicle control (intraperitoneal [i.p.] 100 µl propylene glycol); Group 2, ApoE-paricalcitol (200 ng i.p., 3/week); Group 3, ApoE-Enalapril (30 mg/kg daily); Group 4, ApoE-paricalcitol + enalapril (described dosing); and Group 5, wild-type control (C57BLV).

RESULTS

All treated groups presented significant changes in circulating and cardiac adiponectin, cardiac cholesterol levels, AMPK, MCP-1, TNF-α, COX-2, iNOS, eNOS, CuZn-SOD, Mn-SOD and p22phox. There were 15 genes that differed in their expression, 5 of which are involved in cardioprotection and antithrombotic mechanisms: Bcl2a1a, Col3a1, Spp1 (upregulated), Itga2, and Vwf (downregulated).

CONCLUSION

Together, our data presented a novel role for VDRA and ACEI in reducing factors associated with CHD that may lead to the discovery of new therapeutic venues.

Roles of STATs signaling in cardiovascular diseases

In cardiac and many other systems, chronic stress activates avfamily of structurally and functionally conserved receptors and their downstream signaling molecules that entail tyrosine, serine or threonine phosphorylation to transfer the messages to the genetic machinery. However, the activation of the Janus kinases (JAKs) and their downstream signal transducer and activator of transcription (STATs) proteins is both characteristic of and unique to cytokine and growth factor signaling which plays a central role in heart physiology. Dysregulation of JAK-STAT signaling is associated with various cardiovascular diseases. The molecular signaling and specificity of the JAK-STAT pathway are modulated at many levels by distinct regulatory proteins. Here, we review recent studies on the regulation of the STAT signaling pathway that will enhance our ability to design rational therapeutic strategies for stress-induced heart failure.

High inborn aerobic capacity does not protect the heart following myocardial infarction

Maximal oxygen uptake (Vo2max) is a strong prognostic marker for morbidity and mortality, but the cardio-protective effect of high inborn Vo2max remains unresolved. We aimed to investigate whether rats with high inborn Vo2max yield cardio-protection after myocardial infarction (MI) compared with rats with low inborn Vo2max. Rats breed for high capacity of running (HCR) or low capacity of running (LCR) were randomized into HCR-SH (sham), HCR-MI, LCR-SH, and LCR-MI. Vo2max was lower in HCR-MI and LCR-MI compared with respective sham (P < 0.01), supported by a loss in global cardiac function, assessed by echocardiography. Fura 2-AM loaded cardiomyocyte experiments revealed that HCR-MI and LCR-MI decreased cardiomyocyte shortening (39%, and 34% reduction, respectively, both P < 0.01), lowered Ca(2+) transient amplitude (37%, P < 0.01, and 20% reduction, respectively), and reduced sarcoplasmic reticulum (SR) Ca(2+) content (both; 20%, P < 0.01) compared with respective sham. Diastolic Ca(2+) cycling was impaired in HCR-MI and LCR-MI evidenced by prolonged time to 50% Ca(2+) decay that was partly explained by the 47% (P < 0.01) and 44% (P < 0.05) decrease in SR Ca(2+)-ATPase Ca(2+) removal, respectively. SR Ca(2+) leak increased by 177% in HCR-MI (P < 0.01) and 67% in LCR-MI (P < 0.01), which was abolished by inhibition of Ca(2+)/calmodulin-dependent protein kinase II. This study demonstrates that the effect of MI in HCR rats was similar or even more pronounced on cardiac- and cardiomyocyte contractile function, as well as on Ca(2+) handling properties compared with observations in LCR. Thus our data do not support a cardio-protective effect of higher inborn aerobic capacity.

JAK2/STAT3 activation by melatonin attenuates the mitochondrial oxidative damage induced by myocardial ischemia/reperfusion injury

Ischemia/reperfusion injury (IRI) is harmful to the cardiovascular system and causes mitochondrial oxidative stress. Numerous data indicate that the JAK2/STAT3 signaling pathway is specifically involved in preventing myocardial IRI. Melatonin has potent activity against IRI and may regulate JAK2/STAT3 signaling. This study investigated the protective effect of melatonin pretreatment on myocardial IRI and elucidated its potential mechanism. Perfused isolated rat hearts and cultured neonatal rat cardiomyocytes were exposed to melatonin in the absence or presence of the JAK2/STAT3 inhibitor AG490 or JAK2 siRNA and then subjected to IR. Melatonin conferred a cardio-protective effect, as shown by improved postischemic cardiac function, decreased infarct size, reduced apoptotic index, diminished lactate dehydrogenase release, up-regulation of the anti-apoptotic protein Bcl2, and down-regulation of the pro-apoptotic protein Bax. AG490 or JAK2 siRNA blocked melatonin-mediated cardio-protection by inhibiting JAK2/STAT3 signaling. Melatonin exposure also resulted in a well-preserved mitochondrial redox potential, significantly elevated mitochondrial superoxide dismutase (SOD) activity, and decreased formation of mitochondrial hydrogen peroxide (H2 O2 ) and malondialdehyde (MDA), which indicates that the IR-induced mitochondrial oxidative damage was significantly attenuated. However, this melatonin-induced effect on mitochondrial function was reversed by AG490 or JAK2 siRNA treatment. In summary, our results demonstrate that melatonin pretreatment can attenuate IRI by reducing IR-induced mitochondrial oxidative damage via the activation of the JAK2/STAT3 signaling pathway.

Coronary artery vitamin D receptor expression and plasma concentrations of 25-hydroxyvitamin D: their association with atherosclerosis

OBJECTIVE

The aim of this study was to analyze coronary artery vitamin D receptor (VDR) expression, the plasma concentrations of 25-hydroxyvitamin D3 (25OHD3), and their relationship with coronary artery atherosclerosis.

METHODS

Premenopausal cynomolgus monkeys were fed atherogenic diets containing the equivalent of 1,000 IU/day of vitamin D3. Protein was derived from casein-lactalbumin (C/L, n = 10), soy protein isolate (soy, n = 10), or a combination (n = 19). After 32 months of consuming the diets, each monkey underwent surgical menopause. After 32 postmenopausal months, coronary atherosclerosis was measured in the left circumflex (LCX) artery and left anterior descending (LAD) artery. VDR expression was determined for the LAD, and 25OHD3 concentrations were assessed.

RESULTS

Both the cross-sectional area of atherosclerotic plaques (in square millimeters) and plaque thickness (in millimeters) in the LCX as well as the LAD arteries were analyzed in these monkeys. Those with higher plasma vitamin D3 concentrations and higher VDR were compared with those with higher plasma 25OHD3 concentrations and lower VDR. Significantly smaller plaque sizes were noted with higher plasma 25OHD3 concentrations and higher VDR. For the LCX artery, there was also a significantly lower plaque size (both plaque thickness and cross-sectional area) in those with higher quantities of VDR and lower 25OHD3 concentrations versus those with lower quantities of VDR and higher plasma concentrations of 25OHD3 (P = 0.009 and P = 0.040, respectively).

CONCLUSIONS

Cynomolgus monkeys with higher quantities of VDR have significantly less atherosclerosis than do those with lower quantities of VDR and higher plasma 25OHD3 concentrations. If these findings translate to human beings, it might explain why some individuals with higher plasma concentrations of 25OHD3 have more coronary artery atherosclerosis.