Cardioprotective Effect of Eugenol Against Cd-Induced Inflammation, Oxidative Stress, and Dyslipidemia in Male Rats: An In Vivo and Molecular Docking Study

Cadmium, a highly toxic heavy metal, can cause severe damage to several vital organs including the kidney, liver, and brain. Many of the natural compounds found in aromatic plants have beneficial pharmacological properties. Eugenol is one such compound reported to have anti-inflammatory and antioxidant properties. The aim of this study is to investigate whether eugenol, a natural compound found in aromatic plants known for its anti-inflammatory and antioxidant properties, can mitigate the detrimental effects of cadmium exposure on cardiac inflammation, oxidative stress, and dyslipidemia. Male albino rats were subjected to randomization into four groups, each comprising six animals, to investigate the potential of eugenol in mitigating cadmium-induced toxicity. All groups received oral gavage treatment for 21 days. Following the treatment regimen, cardiac tissue specimens were collected for analysis. The assessment of cardiac antioxidant status entailed the determination of enzymatic activities including catalase, SOD, GST, and GPx. Additionally, levels of lipid peroxidation, reduced glutathione, protein carbonyl oxidation, and thiol levels were quantified in the cardiac tissue samples. To evaluate cardiac damage, marker enzymes such as LDH and CK-MB were measured. Furthermore, the inflammatory response in the cardiac tissue induced by cadmium exposure was assessed through the quantification of NO, TNF-α, and IL-6 levels. Additionally, molecular docking and dynamics studies were conducted utilizing autodock and GLIDE methodologies. Cadmium administration markedly enhanced the activities of LDH and CK-MB, prominent cardiac markers. Furthermore, cadmium treatment also demonstrated a significant decrease in the reduced glutathione levels and antioxidant enzyme activities. Significant elevation of the inflammatory markers was also observed in the cadmium-treated group. Eugenol treatment effectively ameliorates cadmium-induced biochemical changes. This study underscores the potent anti-inflammatory and antioxidant attributes of eugenol. Co-administration of eugenol alongside cadmium exhibited remarkable protective efficacy against cadmium-induced cardio-toxicity. Eugenol demonstrated the capability to reinstate the cellular redox equilibrium of rats subjected to cadmium treatment to levels akin to those of the normal control group.

What do we know about platelets in myocardial ischemia-reperfusion injury and why is it important?

Myocardial ischemia-reperfusion injury (MIRI), the joint result of ischemic injury and reperfusion injury, is associated with poor outcomes in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention. Accumulating evidence demonstrates that activated platelets directly contribute to the pathogenesis of MIRI through participating in the formation of microthrombi, interaction with leukocytes, secretion of active substances, constriction of microvasculature, and activation of spinal afferent nerves. The molecular mechanisms underlying the above detrimental effects of activated platelets include the homotypic and heterotypic interactions through surface receptors, transduction of intracellular signals, and secretion of active substances. Revealing the roles of platelet activation in MIRI and the associated mechanisms would provide potential targets/strategies for the clinical evaluation and treatment of MIRI. Further studies are needed to characterize the temporal (ischemia phase vs. reperfusion phase) and spatial (systemic vs. local) distributions of platelet activation in MIRI by multi-omics strategies. To improve the likelihood of translating novel cardioprotective interventions into clinical practice, basic researches maximally replicating the complexity of clinical scenarios would be necessary.

Cardioprotective properties of quercetin in fescue toxicosis-induced cardiotoxicity via heart-gut axis in lambs (Ovis Aries)

The present study investigated whether quercetin mitigated fescue toxicosis-induced cardiovascular injury via the heart-gut axis. Twenty-four commercial Dorper lambs were stratified by body weight and assigned randomly to diets in one of four groups: endophyte-free without quercetin (E-,Q-), endophyte-positive without quercetin (E+,Q-), endophyte-positive plus 4 g/kg quercetin (E+,Q+) or endophyte-free plus 4 g/kg quercetin (E-,Q+) for 42 days. Body weight and average daily feed intake (ADFI) of lambs fed the endophyte-positive diets showed significant decreases. However, in the groups treated with quercetin, there were significant alterations of cardiac enzymes. Furthermore, reduced fescue toxicosis-induced histopathological lesions of heart and aorta were demonstrated in the E+,Q+ lambs. Results also suggested quercetin eased cardiovascular oxidative injury by inhibiting the increase of oxidative metabolites, and enhancing the levels of antioxidases. Quercetin reduced the inflammation response through suppressing NF-κB signaling pathway activation. Additionally, quercetin ameliorated fescue toxicosis-induced mitochondria dysfunction and improved mitochondrial quality control through enhancing PGC-1α-mediated mitochondrial biogenesis, maintaining the mitochondrial dynamics, and relieving aberrant Parkin/PINK-mediated mitophagy. Quercetin enhanced gastrointestinal microbial alpha and beta diversity, alleviated gut microbiota and microbiome derived metabolites-SCFAs dysbiosis by fescue toxicosis. These findings signified that quercetin may play a cardio-protective role via regulating the heart-gut microbiome axis.

Spinal cord astrocytes regulate myocardial ischemia-reperfusion injury

Astrocytes play a key role in the response to injury and noxious stimuli, but its role in myocardial ischemia-reperfusion (I/R) injury remains largely unknown. Here we determined whether manipulation of spinal astrocyte activity affected myocardial I/R injury and the underlying mechanisms. By ligating the left coronary artery to establish an in vivo I/R rat model, we observed a 1.7-fold rise in glial fibrillary acidic protein (GFAP) protein level in spinal cord following myocardial I/R injury. Inhibition of spinal astrocytes by intrathecal injection of fluoro-citrate, an astrocyte inhibitor, decreased GFAP immunostaining and reduced infarct size by 29% relative to the I/R group. Using a Designer Receptor Exclusively Activated by Designer Drugs (DREADD) chemogenetic approach, we bi-directionally manipulated astrocyte activity employing GFAP promoter-driven Gq- or Gi-coupled signaling. The Gq-DREADD-mediated activation of spinal astrocytes caused transient receptor potential vanilloid 1 (TRPV1) activation and neuropeptide release leading to a 1.3-fold increase in infarct size, 1.2-fold rise in serum norepinephrine level and higher arrhythmia score relative to I/R group. In contrast, Gi-DREADD-mediated inhibition of spinal astrocytes suppressed TRPV1-mediated nociceptive signaling, resulting in 35% reduction of infarct size and 51% reduction of arrhythmia score from I/R group, as well as lowering serum norepinephrine level from 3158 ± 108 to 2047 ± 95 pg/mL. Further, intrathecal administration of TRPV1 or neuropeptide antagonists reduced infarct size and serum norepinephrine level. These findings demonstrate a functional role of spinal astrocytes in myocardial I/R injury and provide a novel potential therapeutic approach targeting spinal cord astrocytes for the prevention of cardiac injury.

Long-term effectiveness of empiric cardio-protection in patients receiving cardiotoxic chemotherapies: A systematic review & bayesian network meta-analysis

BACKGROUND

Cardioprotective therapies represent an important avenue to reduce treatment-limiting cardiotoxicities in patients receiving chemotherapy. However, the optimal duration, strategy and long-term efficacy of empiric cardio-protection remains unknown.

METHODS

Leveraging the MEDLINE/Pubmed, CENTRAL and clinicaltrials.gov databases, we identified all randomised controlled trials investigating cardioprotective therapies from inception to November 2021 (PROSPERO-ID:CRD42021265006). Cardioprotective classes included ACEIs, ARBs, Beta-blockers, dexrazoxane (DEX), statins and mineralocorticoid receptor antagonists. The primary end-point was new-onset heart failure (HF). Secondary outcomes were the mean difference in left ventricular ejection fraction (LVEF) change, hypotension and all-cause mortality. Network meta-analyses were used to assess the cardioprotective effects of each therapy to deduce the most effective therapies. Both analyses were performed using a Bayesian random effects model to estimate risk ratios (RR) and 95% credible intervals (95% CrI).

RESULTS

Overall, from 726 articles, 39 trials evaluating 5931 participants (38.0 ± 19.1 years, 72.0% females) were identified. The use of any cardioprotective strategy associated with reduction in new-onset HF (RR:0.32; 95% CrI:0.19-0.55), improved LVEF (mean difference: 3.92%; 95% CrI:2.81-5.07), increased hypotension (RR:3.27; 95% CrI:1.38-9.87) and no difference in mortality. Based on control arms, the number-needed-to-treat for 'any' cardioprotective therapy to prevent one incident HF event was 45, including a number-needed-to-treat of 21 with ≥1 year of therapy. Dexrazoxane was most effective at HF prevention (Surface Under the Cumulative Ranking curve: 81.47%), and mineralocorticoid receptor antagonists were most effective at preserving LVEF (Surface Under the Cumulative Ranking curve: 99.22%).

CONCLUSION

Cardiotoxicity remains a challenge for patients requiring anticancer therapies. The initiation of extended duration cardioprotection reduces incident HF. Additional head-to-head trials are needed.

Effects of OP2113 on Myocardial Infarct Size and No Reflow in a Rat Myocardial Ischemia/Reperfusion Model

PURPOSE

The present study was to determine whether OP2113 could limit myocardial infarction size and the no-reflow phenomenon in a rat myocardial ischemia/reperfusion model.

METHODS

Rat heart-isolated mitochondria (RHM) were used to investigate mitochondrial respiration and mitochondrial reactive oxygen species (mtROS) generation both in normal conditions and in ischemia/reperfusion-mimicking conditions (using high concentrations of succinate). Human skeletal muscle myoblasts (HSMM) in culture were used to investigate the cellular intermittent deprivation in energy substrates and oxygen as reported in ischemia/reperfusion conditions. In vivo, rats were anesthetized and subjected to 30 min of left coronary artery occlusion followed by 3 h of reperfusion. Rats were randomized to receive OP2113 as an intravenous infusion starting either 5 min prior to coronary artery occlusion (preventive), or 5 min prior to reperfusion (curative), or to receive vehicle starting 5 min prior to coronary artery occlusion. Infusions continued until the end of the study (3 h of reperfusion).

RESULTS

RHM treated with OP2113 showed a concentration-dependent reduction of succinate-induced mtROS generation. In HSMM cells, OP2113 treatment (5-10 μM) during 48H prevented the reduction in the steady-state level of ATP measured just after reperfusion injuries and decreased the mitochondrial affinity to oxygen. In vivo, myocardial infarct size, expressed as the percentage of the ischemic risk zone, was significantly lower in the OP2113-treated preventive group (44.5 ± 2.9%) versus that in the vehicle group (57.0 ± 3.6%; p < 0.05), with a non-significant trend toward a smaller infarct size in the curative group (50.8 ± 3.9%). The area of no reflow as a percentage of the risk zone was significantly smaller in both the OP2113-treated preventive (28.8 ± 2.4%; p = 0.026 vs vehicle) and curative groups (30.1 ± 2.3%; p = 0.04 vs vehicle) compared with the vehicle group (38.9 ± 3.1%). OP2113 was not associated with any hemodynamic changes.

CONCLUSIONS

These results suggest that OP2113 is a promising mitochondrial ROS-modulating agent to reduce no-reflow as well as to reduce myocardial infarct size, especially if it is on board early in the course of the infarction. It appears to have benefit on no-reflow even when administered relatively late in the course of ischemia.

Herbs and their bioactive ingredients in cardio-protection: Underlying molecular mechanisms and evidences from clinical studies

BACKGROUND

Medicinal plants or herbs produce a bounty of bioactive phytochemicals. These phytochemicals can influence a variety of physiological events related to cardiovascular health through multiple underlying mechanisms, such as their role as antioxidative, anti-ischemic, anti-proliferative, hypotensive, anti-thrombotic, and anti-hypercholesterolemic agents.

PURPOSE

The purpose of this review is to summarize and connect evidences supporting the use of phytotherapy in the management of some of the most common cardiovascular impairments, molecular mechanisms underlying cardio-protection mediated by herbs, and clinical studies which are positively linked with the use of herbs in cardiovascular biology. Additionally, we also describe several adverse effects associated with some of the herbal plants and their products to provide a balanced set of studies in favor or against phytotherapy in cardiovascular health that may help global discourses on this matter.

METHODS

Studies relating to the use of medicinal plants were mined by strategically searching scientific databases including Google Scholar, PubMed and Science Direct. Investigations involving approximately 175 articles including reviews, research articles, meta-analyses, and cross-sectional and observational studies were retrieved and analyzed in line with the stated purpose of this study.

RESULTS

A positive correlation between the use of medicinal plants and cardiovascular health was observed. While maintaining cardiovascular physiology, medicinal plants and their derivatives seem to govern a variety of cellular mechanisms involved in vasoconstriction and vasorelaxation, which in turn, are important aspects of cardiovascular homeostasis. Furthermore, a variety of studies including clinical trials, cross-sectional studies, and meta-analyses have also supported the anti-hypertensive and thus, cardio-protective effects, of medicinal plants. Apart from this, evidence is also available for the potential drawbacks of several herbs and their products indicating that the unsupervised use of many herbs may lead to severe health issues.

CONCLUSIONS

The cardio-protective outcomes of medicinal plants and their derivatives are supported by ever-increasing studies, while evidences exist for the potential drawbacks of some of the herbs. A balanced view about the use of medicinal plants and their derivative in cardiovascular biology thus needs to be outlined by researchers and the medical community. The novelty and exhaustiveness of the present manuscript is reflected by the detailed outline of the molecular basis of "herbal cardio-protection", active involvement of several herbs in ameliorating the cardiovascular status, adverse effects of medicinal plants, and the clinical studies considering the use of phytotherapy, all on a single platform.

Cardioprotective Effects and In-Silico Antioxidant Mechanism of L-Ergothioneine In Experimental Type-2 Diabetic Rats

BACKGROUND

Diabetic cardiotoxicity is commonly associated with oxidative injury, inflammation, and endothelial dysfunction. L-ergothioneine (L-egt), a diet-derived amino acid, has been reported to decrease mortality and risk of cardiovascular injury, provides cytoprotection to tissues exposed to oxidative damage, and prevents diabetes-induced perturbation.

OBJECTIVE

This study investigated the cardioprotective effects of L-egt on diabetes-induced cardiovascular injuries and its probable mechanism of action.

METHODS

Twenty-four male Sprague-Dawley rats were divided into non-diabetic (n=6) and diabetic groups (n=18). Six weeks after the induction of diabetes, the diabetic rats were divided into three groups (n=6) and administered distilled water, L-egt (35mg/kg), and losartan (20mg/kg) by oral gavage for six weeks. Blood glucose and mean arterial pressure (MAP) were recorded pre-and post-treatment, while biochemical, ELISA, and Rt-PCR analyses were conducted to determine inflammatory, injury-related and antioxidant biomarkers in cardiac tissue after euthanasia. Also, an in-silico study, including docking and molecular dynamic simulations of L-egt toward the Keap1-Nrf2 protein complex, was done to provide a basis for the molecular antioxidant mechanism of L-egt.

RESULTS

Administration of L-egt to diabetic animals reduced serum triglyceride, water intake, MAP, biomarkers of cardiac injury (CK-MB, LDH), lipid peroxidation, and inflammation. Also, L-egt increased body weight, antioxidant enzymes, upregulated Nrf2, HO-1, NQO1 expression, and decreased Keap1 expression. The in-silico study showed that L-egt inhibits Keap1-Nrf2 complex by binding to the active site of Nrf2 protein, thereby preventing its degradation.

CONCLUSION

L-egt protects against diabetes-induced cardiovascular injury via the upregulation of Keap1-Nrf2 pathway and its downstream cytoprotective antioxidants.

THAP11 down-regulation may contribute to cardio-protective effects of sevoflurane anesthesia: Evidence from clinical and molecular evidence

This study aimed to explore the potential target of the cardio-protective effect induced by sevoflurane anesthesia based on evidence from clinical samples and in vitro model. Forty patients undergoing mitral valve replacement were randomly allocated to receive sevoflurane or propofol-based anesthesia. Atrial muscle specimens were collected from all patients, of which 5 were used to perform transcriptomics analysis. The cTn-I concentration was tested before, at the end of, and 24 h after surgery. In in vitro study, the expression level of the identified target gene, i.e., THAP11, was studied in H9C2 cells treated with sevoflurane or propofol. Then, we studied cell viability using CCK-8 staining, apoptosis by using flow cytometry, and cell death by lactic acid dehydrogenase (LDH) detection in H9C2 cells exposed to oxygen glucose deprivation/reoxygenation (OGD/R) injury. THAP11 was the most significantly down-regulated gene in the transcriptomics analysis (P < 0.001), as confirmed in validation samples (P = 0.006). THAP11 mRNA levels in atrial muscle specimens were positively associated with cTn-I levels at 24-h postoperatively (determination coefficient = 0.564; P < 0.001). Sevoflurane treatment down-regulated THAP11 in H9C2 cell models, which promoted cell viability, inhibited cell apoptosis, and death in the OGD/R injury cell model. Up-regulation of THAP11 reduced the protective effect of sevoflurane treatment against OGD/R injury. Sevoflurane anesthesia down-regulates the expression of THAP11, which contributes to a cardio-protective effect. THAP11 down-regulation promotes cell viability, and inhibits cell apoptosis and death, thereby protecting again myocardial injury; it may therefore be a novel target for perioperative cardio-protection.

Crosstalk between GSK-3β-actuated molecular cascades and myocardial physiology

The finding of "glycogen synthase kinase-3" (GSK-3) was initially identified as a protein kinase that phosphorylate and inhibited glycogen synthase. However, it was soon discovered that GSK-3 also has significant impact in regulation of truly astonishing number of critical intracellular signaling pathways ranging from regulation of cell growth, neurology, heart failure, diabetes, aging, inflammation, and cancer. Recent studies have validated the feasibility of targeting GSK-3 for its vital therapeutic potential to maintain normal myocardial homeostasis, conversely, its loss is incompatible with life as it can abrupt cell cycle and endorse fatal cardiomyopathy. The current study focuses on its expanding therapeutic action in myocardial tissue, concentrating primarily on its role in diabetes-associated cardiac complication, apoptosis and metabolism, heart failure, cardiac hypertrophy, and myocardial infarction. The current report also includes the finding of our previous investigation that has shown the impact of GSK-3β inhibitor against diabetes-associated myocardial injury and experimentally induced myocardial infarction. We have also discussed some recent identified GSK-3β inhibitors for their cardio-protective potential. The crosstalk of various underlying mechanisms that highlight the significant role of GSK-3β in myocardial pathophysiology have been discussed in the present report. For these literatures, we will rely profoundly on our previous studies and those of others to reconcile some of the deceptive contradictions in the literature.

Buddleja saligna Willd (Loganiaceae) inhibits angiotensin-converting enzyme activity in oxidative cardiopathy with concomitant modulation of nucleotide hydrolyzing enzymatic activities and dysregulated lipid metabolic pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Buddleja saligna Willd (Loganiaceae), mostly indigenous to South Africa is traditionally used in the treatment cardio-dysfunctional related ailments amongst other diseases.

AIMS

The cardio-protective effect of B. saligna was investigated in ferric-induced oxidative cardiopathy.

METHODS

Hearts harvested from healthy male SD rats were incubated with 0.1 mM FeSO₄ to induce oxidative damage and co-incubated with B. saligna extract. Reaction mixtures without the extract served as negative control, while tissues without the extract or standard antioxidant (gallic acid) and pro-oxidant served as the normal control. The tissues were analyzed for levels of glutathione, malondialdehyde, and nitric oxide as well as cholinergic, angiotensin-converting enzyme (ACE), lipase, and purinergic enzymes activities, lipid profiles, fatty acid metabolic pathways and metabolites.

RESULTS

Induction of oxidative damage significantly (p < 0.05) depleted the levels of GSH, SOD, catalase, and ENTPDase activities, while concomitantly elevating the levels of MDA, NO, ACE, acetylcholinesterase, lipase and ATPase activities. These levels and activities were significantly reversed on treatment with B. saligna. Treatment with B. saligna also led to depletion of cardiac cholesterol and LDL-c levels, while elevating triglyceride and HDL-c level. It also depleted oxidative-induced lipid metabolites with concomitant generation of thirteen other metabolites. B. saligna also inactivated oxidative-induced pathways for beta oxidation of very long chain fatty acids, glycerolipid metabolism, and fatty acid elongation in mitochondria.

CONCLUSION

These results suggest that B. saligna protects against ferric-induced oxidative cardiopathy by mitigating oxidative stress, while concomitantly inhibiting ACE, acetylcholinesterase and lipase activities, and modulating lipid spectrum and dysregulated metabolic pathways.

Importance of infarct size versus other variables for clinical outcomes after PPCI in STEMI patients

Despite promising experimental studies and encouraging proof-of-concept clinical trials, interventions aimed at limiting infarct size have failed to improve clinical outcomes in patients with ST-elevation myocardial infarction (STEMI). Our objective was to examine whether variables (cardiovascular risk factors, comorbidities, post-procedural variables, cotreatments) might be associated with clinical outcomes in STEMI patients independently from infarct size reduction. The present study was based on a post hoc analysis of the CIRCUS trial database (Clinicaltrials.gov NCT01502774) that assessed the clinical benefit of a single intravenous bolus of cyclosporine in 969 patients with anterior STEMI. Since cyclosporine had no detectable effect on clinical outcomes as well as on any measured variable, we here considered the whole study population as one group. Multivariate analysis was performed to address the respective weight of infarct size and variables in clinical outcomes. Multivariate analysis revealed that several variables (including gender, hypertension, renal dysfunction, TIMI flow grade post-PCI < 3, and treatment administered after PCI with betablockers and angiotensin-converting enzyme inhibitors) had per se a significant influence on the occurrence of [death or hospitalization for heart failure] at 1 year. The relative weight of infarct size and variables on the composite endpoint of [death or hospitalization for heart failure] at 1 year was 18% and 82%, respectively. Several variables contribute strongly to the clinical outcomes of STEMI patients suggesting that cardioprotective strategy might not only focus on infarct size reduction.

Effects of chronic inhibition of Testosterone metabolism on cardiac remodeling after ischemia/reperfusion-induced myocardial damage in gonadectomized rats

The effects of testosterone on cardiovascular homeostasis are still not well understood. The objective of this work was to evaluate the effects of testosterone in the absence or presence of inhibition of Aromatase (4-hydroxyandrostenedione) and/or 5α reductase (Finasteride) enzymatic activities on the myocardial remodeling 30 days after ischemia/reperfusion (I/R) injury in gonadectomized rats. Results showed that testosterone administration to ORX rats resulted in decreased myocardial damaged area, inflammatory infiltrates and reduced MMP-3 and 13 expressions. Interestingly, Finasteride administration resulted in a greater decrease in scar tissue, inflammatory infiltrates, along with a significant decrease in MMP-3 and 13 expressions. In contrast, 4-hydroxyandrostenedione administrations increased all parameters. Our results suggest that testosterone does not have a direct effect since simultaneous inhibition of aromatase and 5α-reductase did not induce significant changes in I/R induced myocardial injury.

Summary: Coronary ischemia/reperfusion-induced injury in gonadectomyzed male rats is decreased by testosterone, protection is increased by blocking its 5α-reduction and blocked by inhibition of its aromatization.

Alleviation of Cardiac Damage by Dietary Fenugreek (Trigonella foenum-graecum) Seeds is Potentiated by Onion (Allium cepa) in Experimental Diabetic Rats via Blocking Renin-Angiotensin System

Hyperglycemia is one of the metabolic and homeostatic abnormalities that increase the cardiovascular mortality in diabetic patients by increased oxidative stress. We have recently reported amelioration of oxidative stress in cardiac tissue by dietary fenugreek (Trigonella foenum-graecum) seeds and onion (Allium cepa) in streptozotocin-induced diabetic rats. The mechanistic aspects of the cardio-protective influence of dietary fenugreek seeds (10%) and onion (3% powder) both individually and in combination on hyperglycemia-mediated cardiac damage was further investigated in this study on streptozotocin-induced diabetic rats. Cardio-protective influence of these dietary spices was evidenced by their blocking potential on renin-angiotensin system. This might be the consequence of reduced activation of angiotensin-converting enzyme (ACE) and angiotensin type 1 receptor (AT₁) in cardiac tissue. The combination produced an additive effect on ACE and AT₁ protein and mRNA expressions. Increased expression of type IV collagen, fibronectin, Bax, 4-hydroxynonenal, iNOS and metabolites of nitric oxide (nitrate/nitrite) along with disturbed PUFA-to-SFA ratio and activities of cardiac marker enzymes in blood confirmed the myocardial damage. Dietary fenugreek seed, onion and fenugreek + onion were found to ameliorate these pathological changes in the cardiovascular system. The beneficial effect being higher with the combination sometime amounting to additive (iNOS expression) or even a synergistic (cardiac Bax and type IV collagen expression and circulatory marker enzymes) in diabetic rats. Thus, the results of present investigation suggested that the combination of fenugreek seeds and onion offers higher beneficial influence in ameliorating cardiac damage accompanying diabetes.

Cardio-protection of ultrafine granular powder for Salvia miltiorrhiza Bunge against myocardial infarction

ETHNOPHARMACOLOGICAL RELEVANCE

Myocardial infarction (MI) is considered as the major inducer to the morbidity and mortality related to coronary occlusion. Salvia miltiorrhiza Bunge is widely applied in the clinic for the prevention and treatment of heart diseases. The preparation of traditional herb decoction (THD) is not only time consuming but also difficult to keep uniform for every time. New usage form of Salvia miltiorrhiza Bunge with characteristics of convenience, uniform and efficiency is needed.

AIM OF THE STUDY

The aims of present study were to investigate the cardio-protection of ultrafine granular powder (UGP) of Salvia miltiorrhiza Bunge; and further compare the characteristics of UGP with THD.

MATERIALS AND METHODS

MI was induced by ligation of the left anterior descending coronary artery near the main pulmonary artery. Cardio-protection of UGP or THD was evaluated based on two sets of experiments, one was acute myocardial infarction (AMI) through 7 days preventive administration, and the other one was chronic cardiac remodeling through 28 days therapeutic administration. Hemodynamic measurement was conducted to evaluate heart function and histopathological detection was used to evaluate heart structure.

RESULTS

No significant improvement of heart structure and function was detected for preventive administration of UGP or THD on AMI rats. While, more significant improvements on left ventricular systolic and diastolic function were detected with therapeutic treatment with 0.81 g/kg UGP than same dose of THD on rats against chronic cardiac remodeling. Both UGP and THD showed the protective effects on heart structure, especially against fibrosis with long-term therapeutic treatment.

CONCLUSIONS

As a new usage form of Salvia miltiorrhiza Bunge, UGP showed significant cardio-protection against myocardial remodeling with therapeutic treatment. Comparing with THD, UGP also holds the advantages of uniform, convenience and efficiency.

Fetal and perinatal stem cells in cardiac regeneration: Moving forward to the paracrine era

Cardiovascular disease (CD) is a major burden for Western society. Regenerative medicine has provided encouraging results, yet it has not addressed the focal defects causing CD and mainly related to the inefficient repair programme of the heart. In this scenario, stem cells have been broadly investigated and their paracrine effect proposed as a possible working strategy to boost endogenous mechanisms of repair and regeneration from within the cardiac tissue. The scientific community is now focusing on identifying the most effective stem cell secretome, as the whole of bioactive factors and extracellular vesicles secreted by stem cells and endowed with regenerative potential. Indeed, the adult stem cell-paracrine potential for cardiac regeneration have been widely analyzed with positive outcome. Nevertheless, low yield, invasive sampling and controversial self-renewal may limit adult stem cell application. On the contrary, fetal and perinatal stem cells, which can be easily isolated from leftover sample via prenatal screening during gestation or as clinical waste material after birth, can offer an ideal alternative. These broadly multipotent immature progenitors share features with both adult and embryonic stem cells, show high self-renewal, but they are not tumorigenic neither cause any ethical concern. While fetal and perinatal stem cells demonstrated to improve cardiac function when injected in the injured heart, the comprehensive characterization of their secretome for future applications is still at its infancy. In this review, we will discuss the paracrine potential of the fetal and perinatal stem cell secretome to provide cardiac repair and resurge the dormant mechanisms of cardiac regeneration for future therapy.

Proteomic analysis of the protective effects of aqueous bark extract of Terminalia arjuna (Roxb.) on isoproterenol-induced cardiac hypertrophy in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Aqueous bark extract of Terminalia arjuna (TA) has been in use as an ethnomedicine for cardiovascular ailments in the Indian subcontinent for centuries. Studies using hemodynamic, ROS scavenging and anti-inflammatory parameters in animal models have shown its anti-atherogenic, hypotensive, inotropic, anti-inflammatory effects. However, details analysis on its effects on established molecular and cell biological markers are a prerequisite for its wider acceptance to the medical community.

AIMS OF THE STUDY

To test the efficacy of TA extract in ameliorating cardiac hypertrophy induced by ISO in rats.

METHODS

Cardiac hypertrophy was induced by ISO (5mg/kg/day s.c. for 14 days) in rats and a standardized aqueous extract of TA stem bark was orally administered by gavage. Total RNA and protein were isolated from control, ISO, ISO plus TA and TA treated rat hearts and analyzed for the transcripts for the markers of hypertrophy, signaling kinases, transcription factors and total protein profile.

RESULTS

TA extract reversed the induction of fetal genes like β-myosin heavy chain, skeletal α-actin and brain natriuretic peptide in hypertrophic rat hearts. While ISO slightly increased the level of phospho-ERK, TA repressed it to about one third of the base line level. Survival kinase Akt, ER stress marker Grp78 and epigenetic regulator HDAC5 were augmented by ISO and TA restored them by various extents. ISO administration moderately increased the transcription factor NFκB binding activity, while coadministration of TA further increased it. AP-1 binding activity was largely unchanged by ISO treatment but it was upregulated when administered along with TA. MEF2D binding activity was increased by ISO and TA restored it to the baseline level. Global proteomic analysis revealed that TA treatment restored a subset of proteins up- and down-regulated in the hypertrophied hearts. Amongst those restored by TA were purinergic receptor X, myosin light chain 3, tropomyosin, and kininogen; suggesting a nodal role of TA in modulating cardiac function.

CONCLUSIONS

This study for the first time reveals that TA partially or completely restores the marker mRNAs, signaling kinases, transcription factors and total protein profile in rat heart, thereby demonstrating its efficacy in preventing ISO-induced cardiac hypertrophy.

Which is the main molecular target responsible for the cardiovascular benefits in the EMPA-REG OUTCOME trial? A journey through the kidney, the heart and other interesting places

BACKGROUND

The results of the EMPA-REG-OUTCOME trial on type 2 diabetic patients at high risk for prior cardiovascular events showed that empagliflozin produces a remarkable reduction in the rates of hospitalization for heart failure (35%), cardiovascular death (38%), and all-cause death (32%). This unexpected cardio-protective action cannot be accounted for by the improvement of "classical" cardiovascular risk factors.

AIMS

This review aims at summarizing current knowledge on the cardiovascular action of SGLT2 inhibitors and discuss the different hypotheses formulated to explain the results of the EMPA-REG-OUTCOME-study.

DATA SYNTHESIS

We discuss in detail the major cardiovascular outcomes of the study in the light of the potential systemic and myocardial mechanisms of action of the drug. In addition, we propose and speculate on a direct effect of empagliflozin on cardiomyocytes.

CONCLUSIONS

The available evidence is insufficient to establish any of the proposed mechanisms of cardiovascular action of empagliflozin. While awaiting for the results of ongoing clinical studies with other SGLT2 inhibitors, the most promising putative mechanisms still deserve to be confirmed with specifically designed, yet unavailable, pre-clinical studies.

Molecular targets for anti-oxidative protection of green tea polyphenols against myocardial ischemic injury

Ischemic heart disease is the leading cause of death worldwide. An improved understanding of the mechanisms involved in myocardial injury would allow intervention downstream in the pathway where certain drugs including natural products could be efficiently applied to target the end effectors of the cell death pathway. Green tea polyphenols (GTPs) have potent anti-oxidative capabilities, which may account for their beneficial effects in preventing oxidative stress associated with ischemia injury. Although studies have provided convincing evidence to support the protective effects of GTPs in cardiovascular system, the potential end effectors that mediate cardiac protection are only beginning to be addressed. Proteomics analyses widely used to identify the protein targets for many cardiovascular diseases have advanced the discovery of the signaling mechanism for GTPs-mediated cardio-protection. This review focuses on putative triggers, mediators, and end effectors for the GTPs-mediated cardio-protection signaling pathways engaged in myocardial ischemia crisis, allowing a promising natural product to be used for ameliorating oxidative stress associated with ischemic heart diseases.

Possible involvement of α1-adrenergic receptor and K(ATP) channels in cardioprotective effect of remote aortic preconditioning in isolated rat heart

BACKGROUND

Remote preconditioning is a phenomenon in which brief episodes of ischemia and reperfusion to remote organs protect the target organ against sustained ischemia/reperfusion (I/R)-induced injury. Protective effects of remote aortic preconditioning (RAPC) are well established in the heart, but their mechanisms still remain to be elucidated.

OBJECTIVE

This study has been designed to investigate the possible involvement of α-1-adrenergic receptor (AR) and K(ATP) channels in cardio-protective effect of RAPC in isolated rat heart.

MATERIALS AND METHODS

Four episodes of ischemia and reperfusion, each comprising of 5 min occlusion and 5 min reperfusion, were used to produce RAPC. Isolated perfused rat heart was subjected to global ischemia for 30 min followed by reperfusion for 120 min. Coronary effluent was analyzed for LDH and CK-MB release to assess the degree of cardiac injury. Myocardial infarct size was estimated macroscopically using TTC staining.

RESULTS

Phenylephrine (20 μ/kg i.p.), as α-1-AR agonist, was noted to produce RAPC-like cardio-protection. However, administration of glibenclamide concomitantly or prior to phenylephrine abolished cardioprotection. Moreover, prazocin (1 mg/kg. i.p), as α-1-AR antagonist and glibenclamide (1 mg/kg i.p), a K(ATP) channel blocker, abolished the cardioprotective effect of RAPC.

CONCLUSION

These data provide the evidence that α-1-AR activation involved in cardioprotective effect of RAPC-mediated trough opening of K(ATP) channels.