The mKATP Channels and protein-kinase C Are Involved in the Cardioprotective Effects of Genistein on Estrogen-Deficient Rat Hearts Exposed to Ischemia/Reperfusion: Energetic Study

Nebivolol in oral subacute treatment prevents cardiac post-ischemic dysfunction in rats, but hyperthyroidism reduces this protection: mechanisms involved

Nebivolol could prevent dysfunction in patients suffering myocardial ischemia. However, influence of hyperthyroidism is not known. Consequences and mechanisms of nebivolol treatment were investigated in isolated hearts from euthyroid (EuT) and hyperthyroid (HpT) rats. Rats were orally treated during 1 week with 20 mg/kg/day nebivolol (O-Neb), 30 mg/kg/day atenolol (O-Ate), or not treated (C). Isolated perfused hearts were exposed to global ischemia and reperfusion (I/R) inside a flow calorimeter. Left diastolic ventricular pressure, developed contractile pressure (P), and total heat rate (Ht) were continuously measured, while infarct size was measured after 2-h R. EuT-C and HpT-C hearts developed similarly low post-ischemic contractile recovery and economy (P/Ht). Nebivolol totally prevented dysfunction and reduced infarction size in EuT hearts, but partially improved recovery in HpT rat hearts. Contrarily, oral atenolol totally prevented dysfunction in HpT hearts but partially in EuT hearts. Nebivolol effects were reversed by perfusing L-NAME in both conditions, but partially reduced by aminoguanidine in HpT. However, L-NAME increased P and P/Ht recoveries in EuT-C and HpT-C rat hearts, as well as melatonin. Oral nebivolol prevented post-ischemic dysfunction and infarction in EuT hearts due to adrenergic β1 blockade and activation of iNOS and/or eNOS, but the effect was attenuated in HpT hearts by excessive iNOS-dependent nitrosative pathways.

Pharmacological Effects of Genistein on Cardiovascular Diseases

Cardiovascular diseases (CVDs) are a group of disorders that involve the heart or blood vessels and are the leading cause of mortality worldwide. Natural products have several pharmacological activities, such as anti-inflammatory, antioxidant, and immunoregulatory properties. This review summarizes the possible therapeutic effects of Genistein on CVD. The information from the current review study was obtained by searching for the keywords such as "Genistein", "Cardiac dysfunction", "hypertrophy", and "Ischemia" "lipid profile" in different online database such as PubMed, Scopus, and Google Scholar, until February 2022. The results of the studies showed that genistein intake has a promising effect on improving cardiac dysfunction, ischemia, and reperfusion of the heart, decreasing cardiac toxicity, modulating lipid profile, and lowering blood pressure. The preventive effects of genistein on experimental models of studies were shown through mechanisms such as anti-inflammatory, antioxidant, and immunomodulatory effects. Pharmacological effects of genistein on cardiac dysfunction, cardiac toxicity, lipid profile, and hypertension indicate the possible remedy effect of this agent in the treatment of CVD.

Natural Products as Modulators of Mitochondrial Dysfunctions Associated with Cardiovascular Diseases: Advances and Opportunities

The mitochondria have an important role in modulating cell cycle progression, cell survival, and apoptosis. In the adult heart, the cardiac mitochondria have a unique spatial arrangement and occupy nearly one-third the volume of a cardiomyocyte, being highly efficient for converting the products of glucose or fatty acid metabolism into adenosine triphosphate (ATP). In cardiomyocytes, the decline of mitochondrial function reduces ATP generation and increases the production of reactive oxygen species, which generates impaired heart function. This is because mitochondria play a key role in maintaining cytosolic calcium concentration and modulation of muscle contraction, as ATP is required to dissociate actin from myosin. Beyond that, mitochondria have a significant role in cardiomyocyte apoptosis because it is evident that patients who have cardiovascular diseases (CVDs) have increased mitochondrial DNA damage to the heart and aorta. Many studies have shown that natural products have mitochondria-modulating effects in cardiac diseases, determining them as potential candidates for new medicines. This review outlines the leading plant secondary metabolites and natural compounds derived from microorganisms as modulators of mitochondrial dysfunctions associated with CVDs.

Flavonoids as new regulators of mitochondrial potassium channels: contribution to cardioprotection

Objectives

Acute myocardial ischemia is one of the major causes of illness in western society. Reduced coronary blood supply leads to cell death and loss of cardiomyocyte population, resulting in serious and often irreversible consequences on myocardial function. Mitochondrial potassium (mitoK) channels have been identified as fine regulators of mitochondrial function and, consequently, in the metabolism of the whole cell, and in the mechanisms underlying the cardioprotection. Interestingly, mitoK channels represent a novel putative target for treating cardiovascular diseases, particularly myocardial infarction, and their modulators represent an interesting tool for pharmacological intervention. In this review, we took up the challenge of selecting flavonoids that show cardioprotective properties through the activation of mitoK channels.

Key findings

A brief overview of the main information on mitoK channels and their participation in the induction of cytoprotective processes was provided. Then, naringenin, quercetin, morin, theaflavin, baicalein, epigallocatechin gallate, genistein, puerarin, luteolin and proanthocyanidins demonstrated to be effective modulators of mitoK channels activity, mediating many beneficial effects.

Summary

The pathophysiological role of mitoK channels has been investigated as well as the impact of flavonoids on this target with particular attention to their potential role in the prevention of cardiovascular disorders.

Proteomics Revealed That Mitochondrial Function Contributed to the Protective Effect of Herba Siegesbeckiae Against Cardiac Ischemia/Reperfusion Injury

Background

Myocardial ischemia/reperfusion (I/R) injury is the main obstacle to percutaneous coronary intervention, lacking effective therapeutic measures in a clinical setting. Herba Siegesbeckiae (HS) is a traditional herb with multiple pharmacological activities and evidence of cardiovascular protection. However, few data are available regarding the role of HS in cardiac I/R. This study aimed to explore the effect and underlying mechanism of HS aqueous extract on cardiac I/R injury.

Materials and Methods

Herba Siegesbeckiae aqueous extract was prepared and analyzed by UHPLC-MS/MS. After intragastric administration of HS once daily for 7 days, male Sprague-Dawley rats were subjected to 30 min occlusion of the left anterior descending coronary artery followed by 120 min reperfusion to elicit I/R. Various parameters like myocardial infarction and apoptosis, 12-lead ECG and hemodynamics, cardiac morphology and myocardial enzymes, quantitative proteomics, mitochondrial ultrastructure and electron transport chain (ETC) function, oxidative stress and antioxidation, and NLRP3 inflammasome and inflammation were evaluated.

Results

The chemical constituents of HS aqueous extract were mainly divided into flavonoids, diterpenoids, and organic acids. In vivo, HS aqueous extract notably alleviated myocardial I/R injury, as evidenced by a reduction in infarct size, apoptotic cells, and cardiac lesion enzymes; decline of ST-segment elevation; improvement of cardiac function; and preservation of morphology. Quantitative proteomics demonstrated that HS reversed the alteration in the expression of Adgb, Cbr1, Decr1, Eif5, Uchl5, Lmo7, Bdh1, Ckmt2, COX7A, and RT1-CE1 after I/R. In addition, HS preserved myocardial ultrastructure and restored the function of mitochondrial ETC complexes following exposure to I/R; HS significantly suppressed I/R-elicited increase of ROS, RNS, MDA, and 8-OHdG, restrained the acetylation of MnSOD, and recovered the activity of MnSOD; and HS reversed I/R-induced elevation of NLRP3 inflammasome and inhibited the release of inflammatory factors and pyroptosis.

Conclusion

Herba Siegesbeckiae aqueous extract ameliorated cardiac I/R injury, which is associated with mitigating oxidative stress, suppressing NLRP3 inflammasome, and restoring mitochondrial function by regulating the expression of Adgb, Cbr1, Decr1, Eif5, Uchl5, Lmo7, Bdh1, Ckmt2, COX7A, and RT1-CE1.

Functional Regulation of KATP Channels and Mutant Insight Into Clinical Therapeutic Strategies in Cardiovascular Diseases

ATP-sensitive potassium channels (K_ATP channels) play pivotal roles in excitable cells and link cellular metabolism with membrane excitability. The action potential converts electricity into dynamics by ion channel-mediated ion exchange to generate systole, involved in every heartbeat. Activation of the K_ATP channel repolarizes the membrane potential and decreases early afterdepolarization (EAD)-mediated arrhythmias. K_ATP channels in cardiomyocytes have less function under physiological conditions but they open during severe and prolonged anoxia due to a reduced ATP/ADP ratio, lessening cellular excitability and thus preventing action potential generation and cell contraction. Small active molecules activate and enhance the opening of the K_ATP channel, which induces the repolarization of the membrane and decreases the occurrence of malignant arrhythmia. Accumulated evidence indicates that mutation of K_ATP channels deteriorates the regulatory roles in mutation-related diseases. However, patients with mutations in K_ATP channels still have no efficient treatment. Hence, in this study, we describe the role of K_ATP channels and subunits in angiocardiopathy, summarize the mutations of the K_ATP channels and the functional regulation of small active molecules in K_ATP channels, elucidate the potential mechanisms of mutant K_ATP channels and provide insight into clinical therapeutic strategies.

A Systematic Review and Meta-Analysis of Phytoestrogen Protects Against Myocardial Ischemia/Reperfusion Injury: Pre-Clinical Evidence From Small Animal Studies

Background: Phytoestrogens are a class of natural compounds that have structural similarities to estrogens. They have been identified to confer potent cardioprotective effects in experimental myocardial ischemia-reperfusion injury (MIRI) animal models. We aimed to investigate the effect of PE on MIRI and its intrinsic mechanisms. Methods: A systematic search was conducted to identify PEs that have been validated in animal studies or clinical studies as effective against MIRI. Then, we collected studies that met inclusion and exclusion criteria from January 2016 to September 2021. The SYRCLE's RoB tool was used to evaluate the quality. Data were analyzed by STATA 16.0 software. Results: The search yielded 18 phytoestrogens effective against heart disease. They are genistein, quercetin, biochanin A, formononetin, daidzein, kaempferol, icariin, puerarin, rutin, notoginsenoside R1, tanshinone IIA, ginsenoside Rb1, ginsenoside Rb3, ginsenoside Rg1, ginsenoside Re, resveratrol, polydatin, and bakuchiol. Then, a total of 20 studies from 17 articles with a total of 355 animals were included in this meta-analysis. The results show that PE significantly reduced the myocardial infarct size in MIRI animals compared with the control group (p < 0.001). PE treatment significantly reduced the creatine kinase level (p < 0.001) and cTnI level (p < 0.001), increased left ventricular ejection fraction (p < 0.001) and left ventricular fractional shortening (p < 0.001) in MIRI animals. In addition, PE also exerts a significant heart rate lowering effect (p < 0.001). Conclusion: Preclinical evidence suggests that PE can be multi-targeted for cardioprotective effects in MIRI. More large animal studies and clinical research are still needed in the future to further confirm its role in MIRI.

Therapeutic Targets for Regulating Oxidative Damage Induced by Ischemia-Reperfusion Injury: A Study from a Pharmacological Perspective

Ischemia-reperfusion (I-R) injury is damage caused by restoring blood flow into ischemic tissues or organs. This complex and characteristic lesion accelerates cell death induced by signaling pathways such as apoptosis, necrosis, and even ferroptosis. In addition to the direct association between I-R and the release of reactive oxygen species and reactive nitrogen species, it is involved in developing mitochondrial oxidative damage. Thus, its mechanism plays a critical role via reactive species scavenging, calcium overload modulation, electron transport chain blocking, mitochondrial permeability transition pore activation, or noncoding RNA transcription. Other receptors and molecules reduce tissue and organ damage caused by this pathology and other related diseases. These molecular targets have been gradually discovered and have essential roles in I-R resolution. Therefore, the current study is aimed at highlighting the importance of these discoveries. In this review, we inquire about the oxidative damage receptors that are relevant to reducing the damage induced by oxidative stress associated with I-R. Several complications on surgical techniques and pathology interventions do not mitigate the damage caused by I-R. Nevertheless, these therapies developed using alternative targets could work as coadjuvants in tissue transplants or I-R-related pathologies

Lepidium meyenii (maca) and soy isoflavones reduce cardiac stunning of ischemia-reperfusion in rats by mitochondrial mechanisms

Background and aim

Phytoestrogens are traditionally used for cardiovascular risks but direct effects on the ischemic heart remain unclear. Plants with phytoestrogens are used for reducing menopausic symptoms and they could also be cardioprotectives. Here we investigated whether maca (Lepidium meyenii) contains isoflavones and prevents cardiac stunning, in comparison to soy isoflavones.

Experimental procedure

Both products were orally and daily administered to rats during 1 week before exposing isolated hearts to ischemia/reperfusion (I/R). Young male (YM), female (YF) and aged female (AgF) rats treated with maca (MACA, 1 g/kg/day) or soy isoflavones (ISOF, 100 mg/kg/day) were compared to acute daidzein (DAZ, 5 mg/kg i.p.) and non-treated rat groups. Isolated ventricles were perfused inside a calorimeter to simultaneously measure contractile and calorimetrical signals before and during I/R.

Results and conclusions

Maca has genistein and daidzein. MACA and ISOF improved the post-ischemic contractile recovery (PICR) and muscle economy (P/Ht) in YM and YF hearts, but not in AgF hearts. DAZ improved PICR and P/Ht more in YM than in YF. The mK_ATP channels blockade reduced both PICR and P/Ht in DAZ-treated YM hearts, without affecting them in ISOF or MACA-treated YM hearts. In MACA treated YF hearts, the simultaneous blockade of NOS and mK_ATP channels, or the mNCX blockade reduced cardioprotection. Results show that subacute oral treatment with maca or with soy isoflavones was strongly preventive of cardiac ischemic dysfunction, more than the acute administration of a pure isoflavone (daidzein, genistein). Maca induced synergistic and complex mechanisms which prevented mitochondrial calcium overload.

Molecular and Cellular Mechanisms Associated with Effects of Molecular Hydrogen in Cardiovascular and Central Nervous Systems

The increased production of reactive oxygen species and oxidative stress are important factors contributing to the development of diseases of the cardiovascular and central nervous systems. Molecular hydrogen is recognized as an emerging therapeutic, and its positive effects in the treatment of pathologies have been documented in both experimental and clinical studies. The therapeutic potential of hydrogen is attributed to several major molecular mechanisms. This review focuses on the effects of hydrogen on the cardiovascular and central nervous systems, and summarizes current knowledge about its actions, including the regulation of redox and intracellular signaling, alterations in gene expressions, and modulation of cellular responses (e.g., autophagy, apoptosis, and tissue remodeling). We summarize the functions of hydrogen as a regulator of nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated redox signaling and the association of hydrogen with mitochondria as an important target of its therapeutic action. The antioxidant functions of hydrogen are closely associated with protein kinase signaling pathways, and we discuss possible roles of the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) and Wnt/β-catenin pathways, which are mediated through glycogen synthase kinase 3β and its involvement in the regulation of cellular apoptosis. Additionally, current knowledge about the role of molecular hydrogen in the modulation of autophagy and matrix metalloproteinases-mediated tissue remodeling, which are other responses to cellular stress, is summarized in this review.