Mitophagy in Cardiovascular Diseases

Role of cardiolipin in regulating and treating atherosclerotic cardiovascular diseases

Cardiovascular diseases, mainly caused by atherosclerosis, are the leading causes of morbidity and mortality worldwide. Despite the discrepancies in clinical manifestations between different abnormalities, atherosclerosis shares similar pathophysiological processes, such as mitochondrial dysfunction. Cardiolipin (CL) is a conserved mitochondria-specific lipid that contributes to the cristae structure of the inner mitochondrial membrane (IMM). Alterations in the CL, including oxidative modification, reduced quantity, and abnormal localization, contribute to the onset and progression of atherosclerosis. In this review, we summarize the knowledge that CL is involved in the pathogenesis of atherosclerosis. On the one hand, CL and its oxidative modification promote the progression of atherosclerosis via several mechanisms, including oxidative stress, apoptosis, and inflammation in response to stress. On the other hand, CL externalizes to the outer mitochondrial membrane (OMM) and acts as the pivotal "eat-me" signal in mitophagy, removing dysfunctional mitochondria and safeguarding against the progression of atherosclerosis. Given the imbalance between proatherogenic and antiatherogenic effects, we provide our understanding of the roles of the CL and its oxidative modification in atherosclerotic cardiovascular diseases, in addition to potential therapeutic strategies aimed at restoring the CL. Briefly, CL is far more than a structural IMM lipid; broader significances of the evolutionarily conserved lipid need to be explored.

Macrophages in vascular disease: Roles of mitochondria and metabolic mechanisms

Macrophages are a dynamic cell type of the immune system implicated in the pathophysiology of vascular diseases and are a major contributor to pathological inflammation. Excessive macrophage accumulation, activation, and polarization is observed in aortic aneurysm (AA), atherosclerosis, and pulmonary arterial hypertension. In general, macrophages become activated and polarized to a pro-inflammatory phenotype, which dramatically changes cell behavior to become pro-inflammatory and infiltrative. These cell types become cumbersome and fail to be cleared by normal mechanisms such as autophagy. The result is a hyper-inflammatory environment causing the recruitment of adjacent cells and circulating immune cells to further augment the inflammatory response. In AA, this leads to excessive ECM degradation and chemokine secretion, ultimately causing macrophages to dominate the immune cell landscape in the aortic wall. In atherosclerosis, monocytes are recruited to the vascular wall, where they polarize to the pro-inflammatory phenotype and induce inflammatory pathway activation. This leads to the development of foam cells, which significantly contribute to neointima and necrotic core formation in atherosclerotic plaques. Pro-inflammatory macrophages, which affect other vascular diseases, present with fragmented mitochondria and corresponding metabolic dysfunction. Targeting macrophage mitochondrial dynamics has proved to be an exciting potential therapeutic approach to combat vascular disease. This review will summarize mitochondrial and metabolic mechanisms of macrophage activation, polarization, and accumulation in vascular diseases.

Sweroside alleviates pressure overload-induced heart failure through targeting CaMKⅡδ to inhibit ROS-mediated NF-κB/NLRP3 in cardiomyocytes

Ongoing inflammation in the heart is positively correlated with adverse remodeling, characterized by elevated levels of cytokines that stimulate activation of cardiac fibroblasts. It was found that CaMKIIδ response to Ang II or TAC triggers the accumulation of ROS in cardiomyocytes, which subsequently stimulates NF-κB/NLRP3 and leads to an increase in IL-6, IL-1β, and IL-18. This is an important causative factor in the occurrence of adverse remodeling in heart failure. Sweroside is a biologically active natural iridoids extracted from Lonicerae Japonicae Flos. It shows potent anti-inflammatory and antioxidant activity in various cardiovascular diseases. In this study, we found that sweroside inhibited ROS-mediated NF-κB/NLRP3 in Ang II-treated cardiomyocytes by directly binding to CaMKIIδ. Knockdown of CaMKⅡδ abrogated the effect of sweroside regulation on NF-κB/NLRP3 in cardiomyocytes. AAV-CaMKⅡδ induced high expression of CaMKⅡδ in the myocardium of TAC/Ang II-mice, and the inhibitory effect of sweroside on TAC/Ang Ⅱ-induced elevation of NF-κB/NLRP3 was impeded. Sweroside showed significant inhibitory effects on CaMKIIδ/NF-κB/NLRP3 in cardiomyocytes from TAC/Ang Ⅱ-induced mice. This would be able to mitigate the adverse events of myocardial remodeling and contractile dysfunction at 8 weeks after the onset of the inflammatory response. Taken together, our findings have revealed the direct protein targets and molecular mechanisms by which sweroside improves heart failure, thereby supporting the further development of sweroside as a therapeutic agent for heart failure.

Diabetes cardiomyopathy: targeted regulation of mitochondrial dysfunction and therapeutic potential of plant secondary metabolites

Diabetic cardiomyopathy (DCM) is a specific heart condition in diabetic patients, which is a major cause of heart failure and significantly affects quality of life. DCM is manifested as abnormal cardiac structure and function in the absence of ischaemic or hypertensive heart disease in individuals with diabetes. Although the development of DCM involves multiple pathological mechanisms, mitochondrial dysfunction is considered to play a crucial role. The regulatory mechanisms of mitochondrial dysfunction mainly include mitochondrial dynamics, oxidative stress, calcium handling, uncoupling, biogenesis, mitophagy, and insulin signaling. Targeting mitochondrial function in the treatment of DCM has attracted increasing attention. Studies have shown that plant secondary metabolites contribute to improving mitochondrial function and alleviating the development of DCM. This review outlines the role of mitochondrial dysfunction in the pathogenesis of DCM and discusses the regulatory mechanism for mitochondrial dysfunction. In addition, it also summarizes treatment strategies based on plant secondary metabolites. These strategies targeting the treatment of mitochondrial dysfunction may help prevent and treat DCM.

Role of mitochondrial homeostasis in D-galactose-induced cardiovascular ageing from bench to bedside

Ageing is an inevitable phenomenon which affects the cellular to the organism level in the progression of the time. Oxidative stress and inflammation are now widely regarded as the key processes involved in the aging process, which may then cause significant harm to mitochondrial DNA, leading to apoptosis. Normal circulatory function is a significant predictor of disease-free life expectancy. Indeed, disorders affecting the cardiovascular system, which are becoming more common, are the primary cause of worldwide morbidity, disability, and mortality. Cardiovascular aging may precede or possibly underpin overall, age-related health decline. Numerous studies have foundmitochondrial mechanistc approachplays a vital role in the in the onset and development of aging. The D-galactose (D-gal)-induced aging model is well recognized and commonly used in the aging study. In this review we redeposit the association of the previous and current studies on mitochondrial homeostasis and its underlying mechanisms in D-galactose cardiovascular ageing. Further we focus the novel and the treatment strategies to combat the major complication leading to the cardiovascular ageing.

Differences in autophagy marker levels at birth in preterm vs. term infants

BACKGROUND

Preterm infants are susceptible to oxidative stress and prone to respiratory diseases. Autophagy is an important defense mechanism against oxidative-stress-induced cell damage and involved in lung development and respiratory morbidity. We hypothesized that autophagy marker levels differ between preterm and term infants.

METHODS

In the prospective Basel-Bern Infant Lung Development (BILD) birth cohort we compared cord blood levels of macroautophagy (Beclin-1, LC3B), selective autophagy (p62) and regulation of autophagy (SIRT1) in 64 preterm and 453 term infants.

RESULTS

Beclin-1 and LC3B did not differ between preterm and term infants. However, p62 was higher (0.37, 95% confidence interval (CI) 0.05;0.69 in log2-transformed level, p = 0.025, padj = 0.050) and SIRT1 lower in preterm infants (-0.55, 95% CI -0.78;-0.31 in log2-transformed level, padj < 0.001). Furthermore, p62 decreased (padj-value for smoothing function was 0.018) and SIRT1 increased (0.10, 95% CI 0.07;0.13 in log2-transformed level, padj < 0.001) with increasing gestational age.

CONCLUSION

Our findings suggest differential levels of key autophagy markers between preterm and term infants. This adds to the knowledge of the sparsely studied field of autophagy mechanisms in preterm infants and might be linked to impaired oxidative stress response, preterm birth, impaired lung development and higher susceptibility to respiratory morbidity in preterm infants.

IMPACT

To the best of our knowledge, this is the first study to investigate autophagy marker levels between human preterm and term infants in a large population-based sample in cord blood plasma This study demonstrates differential levels of key autophagy markers in preterm compared to term infants and an association with gestational age This may be linked to impaired oxidative stress response or developmental aspects and provide bases for future studies investigating the association with respiratory morbidity.

The mitochondrial link: Phthalate exposure and cardiovascular disease

Phthalates' pervasive presence in everyday life poses concern as they have been revealed to induce perturbing health defects. Utilized as a plasticizer, phthalates are riddled throughout many common consumer products including personal care products, food packaging, home furnishings, and medical supplies. Phthalates permeate into the environment by leaching out of these products which can subsequently be taken up by the human body. It is previously established that a connection exists between phthalate exposure and cardiovascular disease (CVD) development; however, the specific mitochondrial link in this scenario has not yet been described. Prior studies have indicated that one possible mechanism for how phthalates exert their effects is through mitochondrial dysfunction. By disturbing mitochondrial structure, function, and signaling, phthalates can contribute to the development of the foremost cause of death worldwide, CVD. This review will examine the potential link among phthalates and their effects on the mitochondria, permissive of CVD development.

Role of PTEN-Induced Protein Kinase 1 as a Mitochondrial Dysfunction Regulator in Cardiovascular Disease Pathogenesis

Cardiovascular disease (CVD) remains a global health challenge, primarily due to atherosclerosis, which leads to conditions such as coronary artery disease, cerebrovascular disease, and peripheral arterial disease. Mitochondrial dysfunction initiates endothelial dysfunction, a key contributor to CVD pathogenesis, as well as triggers the accumulation of reactive oxygen species (ROS), energy stress, and cell death in endothelial cells, which are crucial for atherosclerosis development. This review explores the role of PTEN-induced protein kinase 1 (PINK1) in mitochondrial quality control, focusing on its significance in cardiovascular health. PINK1 plays a pivotal role in mitophagy (selective removal of damaged mitochondria), contributing to the prevention of CVD progression. PINK1-mediated mitophagy also affects the maintenance of cardiomyocyte homeostasis in ischemic heart disease, thus mitigating mitochondrial dysfunction and oxidative stress, as well as regulates endothelial health in atherosclerosis through influencing ROS levels and inflammatory response. We also investigated the role of PINK1 in vascular smooth muscle cells, emphasizing on its role in apoptosis and atherosclerosis. Dysfunctional mitophagy in these cells accelerates cellular senescence and contributes to adverse effects including plaque rupture and inflammation. Mitophagy has also been explored as a potential therapeutic target for vascular calcification, a representative lesion in atherosclerosis, with a focus on lactate-induced mechanisms. Finally, we highlight the current research and clinical trials targeting mitophagy as a therapeutic avenue for CVD.

Mitochondrial Dysfunction in Heart Failure: From Pathophysiological Mechanisms to Therapeutic Opportunities

Mitochondrial dysfunction, a feature of heart failure, leads to a progressive decline in bioenergetic reserve capacity, consisting in a shift of energy production from mitochondrial fatty acid oxidation to glycolytic pathways. This adaptive process of cardiomyocytes does not represent an effective strategy to increase the energy supply and to restore the energy homeostasis in heart failure, thus contributing to a vicious circle and to disease progression. The increased oxidative stress causes cardiomyocyte apoptosis, dysregulation of calcium homeostasis, damage of proteins and lipids, leakage of mitochondrial DNA, and inflammatory responses, finally stimulating different signaling pathways which lead to cardiac remodeling and failure. Furthermore, the parallel neurohormonal dysregulation with angiotensin II, endothelin-1, and sympatho-adrenergic overactivation, which occurs in heart failure, stimulates ventricular cardiomyocyte hypertrophy and aggravates the cellular damage. In this review, we will discuss the pathophysiological mechanisms related to mitochondrial dysfunction, which are mainly dependent on increased oxidative stress and perturbation of the dynamics of membrane potential and are associated with heart failure development and progression. We will also provide an overview of the potential implication of mitochondria as an attractive therapeutic target in the management and recovery process in heart failure.

Modeling drug-induced mitochondrial toxicity with human primary cardiomyocytes

Mitochondrial toxicity induced by therapeutic drugs is a major contributor for cardiotoxicity, posing a serious threat to pharmaceutical industries and patients' lives. However, mitochondrial toxicity testing is not incorporated into routine cardiac safety screening procedures. To accurately model native human cardiomyocytes, we comprehensively evaluated mitochondrial responses of adult human primary cardiomyocytes (hPCMs) to a nucleoside analog, remdesivir (RDV). Comparison of their response to human pluripotent stem cell-derived cardiomyocytes revealed that the latter utilized a mitophagy-based mitochondrial recovery response that was absent in hPCMs. Accordingly, action potential duration was elongated in hPCMs, reflecting clinical incidences of RDV-induced QT prolongation. In a screen for mitochondrial protectants, we identified mitochondrial ROS as a primary mediator of RDV-induced cardiotoxicity. Our study demonstrates the utility of hPCMs in the detection of clinically relevant cardiac toxicities, and offers a framework for hPCM-based high-throughput screening of cardioprotective agents.

Insulin-like growth factor binding protein 2: a core biomarker of left ventricular dysfunction in dilated cardiomyopathy

BACKGROUND

RNA modifications, especially N6-methyladenosine, N1-methyladenosine and 5-methylcytosine, play an important role in the progression of cardiovascular disease. However, its regulatory function in dilated cardiomyopathy (DCM) remains to be undefined.

METHODS

In the study, key RNA modification regulators (RMRs) were screened by three machine learning models. Subsequently, a risk prediction model for DCM was developed and validated based on these important genes, and the diagnostic efficiency of these genes was assessed. Meanwhile, the relevance of these genes to clinical traits was explored. In both animal models and human subjects, the gene with the strongest connection was confirmed. The expression patterns of important genes were investigated using single-cell analysis.

RESULTS

A total of 4 key RMRs were identified. The risk prediction models were constructed basing on these genes which showed a good accuracy and sensitivity in both the training and test set. Correlation analysis showed that insulin-like growth factor binding protein 2 (IGFBP2) had the highest correlation with left ventricular ejection fraction (LVEF) (R = -0.49, P = 0.00039). Further validation expression level of IGFBP2 indicated that this gene was significantly upregulated in DCM animal models and patients, and correlation analysis validation showed a significant negative correlation between IGFBP2 and LVEF (R = -0.87; P = 6*10-5). Single-cell analysis revealed that this gene was mainly expressed in endothelial cells.

CONCLUSION

In conclusion, IGFBP2 is an important biomarker of left ventricular dysfunction in DCM. Future clinical applications could possibly use it as a possible therapeutic target.

Hydrogen sulfide inhibits gene expression associated with aortic valve degeneration by inducing NRF2-related pro-autophagy effect in human aortic valve interstitial cells

Aortic valve stenosis (AS) is the most common valvular heart disease but there are currently no effective medical treatments that can delay disease progression due to a lack of knowledge of the precise pathophysiology. The expression of sulfide: quinone oxidoreductase (SQOR) and nuclear factor erythroid 2-related factor 2 (NRF2) was decreased in the aortic valve of AS patients. However, the role of SQOR and NRF2 in the pathophysiology of AS has not been found. We investigated the effects of hydrogen sulfide (H2S)-releasing compounds on diseased aortic valve interstitial cells (AVICs) to explain the cellular mechanism of SQOR and elucidate the medical value of H2S for AS treatment. Sodium hydrosulfide (NaHS) treatment increased the expression of SQOR and NRF2 gene and consequently induced the NRF2 target genes, such as NAD(P)H quinone dehydrogenase 1 and cystathionine γ-lyase. In addition, NaHS dose-dependently decreased the expression level of fibrosis and inflammation-related genes (MMP9, TNF-α, IL6) and calcification-related genes (ALP, osteocalcin, RUNX2, COL1A1) in human AVICs. Furthermore, NaHS activated the AMPK-mTOR pathway and inhibited the PI3K-AKT pathway, resulting in a pro-autophagy effect in human AVICs. An NRF2 inhibitor, brusatol, attenuated NaHS-induced AMPK activation and decreased the autophagy markers Beclin-1 and LC3AB, suggesting that the mechanism of action of H2S is related to NRF2. In conclusion, H2S decreased gene expression levels related to aortic valve degeneration and activated AMPK-mTOR-mediated pro-autophagy function associated with NRF2 in human AVICs. Therefore, H2S could be a potential therapeutic target for the development of AS treatment.

Computational Assessment of Unsteady Flow Effects on Magnetic Nanoparticle Targeting Efficiency in a Magnetic Stented Carotid Bifurcation Artery

PURPOSE

Worldwide, cardiovascular disease is the leading cause of hospitalization and death. Recently, the use of magnetizable nanoparticles for medical drug delivery has received much attention for potential treatment of both cancer and cardiovascular disease. However, proper understanding of the interacting magnetic field forces and the hydrodynamics of blood flow is needed for effective implementation. This paper presents the computational results of simulated implant assisted medical drug targeting (IA-MDT) via induced magnetism intended for administering patient specific doses of therapeutic agents to specific sites in the cardiovascular system. The drug delivery scheme presented in this paper functions via placement of a faintly magnetizable stent at a diseased location in the carotid artery, followed by delivery of magnetically susceptible drug carriers guided by the local magnetic field. Using this method, the magnetic stent can apply high localized magnetic field gradients within the diseased artery, while only exposing the neighboring tissues, arteries, and organs to a modest magnetic field. The localized field gradients also produce the forces needed to attract and hold drug-containing magnetic nanoparticles at the implant site for delivering therapeutic agents to treat in-stent restenosis.

METHODS

The multi-physics computational model used in this work is from our previous work and has been slightly modified for the case scenario presented in this paper. The computational model is used to analyze pulsatile blood flow, particle motion, and particle capture efficiency in a magnetic stented region using the magnetic properties of magnetite (Fe3O4) and equations describing the magnetic forces acting on particles produced by an external cylindrical electromagnetic coil. The electromagnetic coil produces a uniform magnetic field in the computational arterial flow model domain, while both the particles and the implanted stent are paramagnetic. A Eulerian-Lagrangian technique is adopted to resolve the hemodynamic flow and the motion of particles under the influence of a range of magnetic field strengths (Br = 2T, 4T, 6T, and 8T). Particle diameter sizes of 10 nm-4 µm in diameter were evaluated. Two dimensionless numbers were evaluated in this work to characterize relative effects of Brownian motion (BM), magnetic force induced particle motion, and convective blood flow on particle motion.

RESULTS

The computational simulations demonstrate that the greatest particle capture efficiency results for particle diameters within the micron range of 0.7-4 µm, specifically in regions where flow separation and vortices are at a minimum. Similar to our previous work (which did not involve the use of a magnetic stent), it was also observed that the capture efficiency of particles decreases substantially with particle diameter, especially in the superparamagnetic regime. Contrary to our previous work, using a magnetic stent tripled the capture efficiency of superparamagnetic particles. The highest capture efficiency observed for superparamagnetic particles was 78% with an 8 T magnetic field strength and 65% with a 2 T magnetic field strength when analyzing 100 nm particles. For 10 nm particles and an 8 T magnetic field strength, the particle capture efficiency was 55% and for a 2 T magnetic field strength the particle capture efficiency was observed to be 43%. Furthermore, it was found that larger magnetic field strengths, large particle diameter sizes (1 µm and above), and slower blood flow velocity improves the particle capture efficiency. The distribution of captured particles on the vessel wall along the axial and azimuthal directions is also discussed. Results for captured particles on the vessel wall along the axial flow direction showed that the particle density decreased along the axial direction, especially after the stented region. For the entrance section of the stented region, the captured particle density distribution along the axial direction is large, corresponding to the center-symmetrical distribution of the magnetic force in that section.

CONCLUSION

The simulation results presented in this work have shown to yield favorable capture efficiencies for micron range particles and superparamagnetic particles using magnetized implants such as the stent discussed in this work. The results presented in this work justify further investigation of MDT as a treatment technique for cardiovascular disease.

Mitochondrial dysfunction at the crossroad of cardiovascular diseases and cancer

A large body of evidence indicates the existence of a complex pathophysiological relationship between cardiovascular diseases and cancer. Mitochondria are crucial organelles whose optimal activity is determined by quality control systems, which regulate critical cellular events, ranging from intermediary metabolism and calcium signaling to mitochondrial dynamics, cell death and mitophagy. Emerging data indicate that impaired mitochondrial quality control drives myocardial dysfunction occurring in several heart diseases, including cardiac hypertrophy, myocardial infarction, ischaemia/reperfusion damage and metabolic cardiomyopathies. On the other hand, diverse human cancers also dysregulate mitochondrial quality control to promote their initiation and progression, suggesting that modulating mitochondrial homeostasis may represent a promising therapeutic strategy both in cardiology and oncology. In this review, first we briefly introduce the physiological mechanisms underlying the mitochondrial quality control system, and then summarize the current understanding about the impact of dysregulated mitochondrial functions in cardiovascular diseases and cancer. We also discuss key mitochondrial mechanisms underlying the increased risk of cardiovascular complications secondary to the main current anticancer strategies, highlighting the potential of strategies aimed at alleviating mitochondrial impairment-related cardiac dysfunction and tumorigenesis. It is hoped that this summary can provide novel insights into precision medicine approaches to reduce cardiovascular and cancer morbidities and mortalities.

Cardiovascular Stents: Types and Future Landscape

One of the prominent reasons for mortality and morbidity worldwide is coronary artery disease (CAD), an ailment that manifests itself by the narrowing of the artery with the deposition of plaque. The definitive mode of action for dealing with this condition is using a medical device known as a stent at the affected location. This extremely important tubular equipment helps tremendously with vessel support. It also helps by keeping the path of blood flow clear for the heart muscle masses, its crucial nutrients, and oxygen supply. Several generations of stents have been continuously developed to improve patient outcomes and reduce side effects post-stent implantation. As we move from bare metal stents (BMSs) to drug-eluting stents (DESs) and, more recently, to bioabsorbable stents, the research area continues to develop. The use of this biomedical device has increased the standard of living in many cases; therefore, it is much needed to work on the possible growth areas in the cardiovascular stents and improve them to such an extent that the patients suffering from cardiovascular ailments get to live a comfortable life. Most articles deal with stents that are available for current use and their various types. They also cover the topic of stent optimization, as it is one of the key factors in enhancing stent usability and plays a prominent role in optimizing stent placement in the vessels of the body. To keep in touch with advances in stent technology over the past few decades, this article reviews advances in the devices, working on how available stents can be optimized to create new stents.

Autophagy-related proteins: Potential diagnostic and prognostic biomarkers of aging-related diseases

Autophagy plays a key role in cellular, tissue and organismal homeostasis and in the production of the energy load needed at critical times during development and in response to nutrient shortage. Autophagy is generally considered as a pro-survival mechanism, although its deregulation has been linked to non-apoptotic cell death. Autophagy efficiency declines with age, thus contributing to many different pathophysiological conditions, such as cancer, cardiomyopathy, diabetes, liver disease, autoimmune diseases, infections, and neurodegeneration. Accordingly, it has been proposed that the maintenance of a proper autophagic activity contributes to the extension of the lifespan in different organisms. A better understanding of the interplay between autophagy and risk of age-related pathologies is important to propose nutritional and life-style habits favouring disease prevention as well as possible clinical applications aimed at promoting long-term health.

Inhibition of Myocardial Remodeling and Heart Failure by Traditional Herbal Medications: Evidence from Ginseng and ginkgo biloba

Herbal-based medications have been used as therapeutic agents for thousands of years, particularly in Asian cultures. It is now well established that these herbal medications contain potent bioactive phytochemicals which exert a plethora of beneficial effects such as those seen on the cardiovascular system. Among the most widely studied of these herbal agents is ginseng, a member of the genus Panax, which has been shown to produce beneficial effects in terms of reducing cardiac pathology, at least in experimental studies. The beneficial effects of ginseng observed in such studies are likely attributable to their constituent ginsenosides, which are steroid-like saponins of which there are at least 100 and which vary according to ginseng species. Many ginseng species such as Panax ginseng (also known as Asian ginseng) and P quinquefolius (North American ginseng) as well as specific ginsenosides have been shown to attenuate hypertrophy as well as other indices of myocardial remodeling in a wide variety of experimental models. Ginkgo biloba on the other hand has been much less studied although the leaf extract of the ancient ginkgo tree has similarly consistently been shown to produce anti-remodeling effects. Ginkgo's primary bioactive constituents are thought to be terpene trilactones called ginkgolides, of which there are currently seven known types. Ginkgo and ginkgolides have also been shown to produce anti-remodeling effects as have been shown for ginseng in a variety of experimental models, in some cases via similar mechanisms. Although a common single mechanism for the salutary effects of these compounds is unlikely, there are a number of examples of shared effects including antioxidant and antiapoptotic effects as well as inhibition of pro-hypertrophic intracellular signaling such as that involving the calcineurin pathway which results in the upregulation of pro-hypertrophic genes. Robust clinical evidence represented by large scale phase 3 trials is lacking although there is limited supporting evidence from small trials at least with respect to ginseng. Taken together, both ginseng and ginkgo as well as their bioactive components offer potential as adjuvant therapy for the treatment of myocardial remodeling and heart failure.

Emerging role of mitophagy in heart failure: from molecular mechanism to targeted therapy

Heart failure is defined as a drop in heart's pump function, accounting for reduced blood output and venous stasis, and constitutes the end stage of various cardiovascular diseases. Although mild mitochondrial dysfunction may hinder cardiomyocyte metabolism and impair myocardial function, severe mitochondrial injury is accompanied by cardiomyocyte apoptosis, leading to irreversible damage of the heart. Selective autophagy of mitochondria, or mitophagy, serves to rapidly remove dysfunctional mitochondria and restore the health of the mitochondrial population within cells by allowing reutilization of degradative substrates such as amino acids, fatty acids, and nucleotides. Although mitophagy represents a protective program that prevents the accumulation of poorly structured or damaged mitochondria, excessive mitophagy leads to mitochondrial population decline, impaired oxidative phosphorylation, and decreased ATP production. In this review, we first discuss the molecular underpinnings of mitophagy and the roles of different mitophagy adaptors. Then, the multiple and complex influence of mitophagy on heart failure is summarized. Finally, novel pharmacological strategies targeting mitophagy to relieve heart failure are briefly summarized.

Differential Role of Active Compounds in Mitophagy and Related Neurodegenerative Diseases

Neurodegenerative diseases, such as Alzheimer’s disease or Parkinson’s disease, significantly reduce the quality of life of patients and eventually result in complete maladjustment. Disruption of the synapses leads to a deterioration in the communication of nerve cells and decreased plasticity, which is associated with a loss of cognitive functions and neurodegeneration. Maintaining proper synaptic activity depends on the qualitative composition of mitochondria, because synaptic processes require sufficient energy supply and fine calcium regulation. The maintenance of the qualitative composition of mitochondria occurs due to mitophagy. The regulation of mitophagy is usually based on several internal mechanisms, as well as on signals and substances coming from outside the cell. These substances may directly or indirectly enhance or weaken mitophagy. In this review, we have considered the role of some compounds in process of mitophagy and neurodegeneration. Some of them have a beneficial effect on the functions of mitochondria and enhance mitophagy, showing promise as novel drugs for the treatment of neurodegenerative pathologies, while others contribute to a decrease in mitophagy.

Comprehensive Analysis of Mitochondrial Dynamics Alterations in Heart Diseases

The most common alterations affecting mitochondria, and associated with cardiac pathological conditions, implicate a long list of defects. They include impairments of the mitochondrial electron transport chain activity, which is a crucial element for energy formation, and that determines the depletion of ATP generation and supply to metabolic switches, enhanced ROS generation, inflammation, as well as the dysregulation of the intracellular calcium homeostasis. All these signatures significantly concur in the impairment of cardiac electrical characteristics, loss of myocyte contractility and cardiomyocyte damage found in cardiac diseases. Mitochondrial dynamics, one of the quality control mechanisms at the basis of mitochondrial fitness, also result in being dysregulated, but the use of this knowledge for translational and therapeutic purposes is still in its infancy. In this review we tried to understand why this is, by summarizing methods, current opinions and molecular details underlying mitochondrial dynamics in cardiac diseases.

Mitochondrial cargo export in exosomes: Possible pathways and implication in disease biology

Exosome biogenesis occurs parallel to multiple endocytic traffic routes. These coexisting routes drive cargo loading in exosomes via overlapping of exosome biogenesis with endosomal pathways. One such pathway is autophagy which captures damaged intracellular organelles or their components in an autophagosome vesicle and route them for lysosomal degradation. However, in case of a noncanonical fusion event between autophagosome and maturing multivesicular body (MVB)-a site for exosome biogenesis, the autophagic cargo is putatively loaded in exosomes and subsequent released out of the cell via formation of an "amphisome" like structure. Similarly, during "mitophagy" or mitochondrial (mt) autophagy, amphisome formation routes mitophagy cargo to exosomes. These mt-cargo enriched exosomes or mt-enREXO are often positive for LC3 protein-an autophagic flux marker, and potent regulators of paracrine signaling with both homeostatic and pathological roles. Here, I review this emerging concept and discuss how intracellular autophagic routes helps in generation of mt-enREXO and utility of these vesicles in paracrine cellular signaling and diagnostic areas.

Computational Assessment of Magnetic Nanoparticle Targeting Efficiency in a Simplified Circle of Willis Arterial Model

This paper presents the methodology and computational results of simulated medical drug targeting (MDT) via induced magnetism intended for administering intravenous patient-specific doses of therapeutic agents in a Circle of Willis (CoW) model. The multi-physics computational model used in this work is from our previous works. The computational model is used to analyze pulsatile blood flow, particle motion, and particle capture efficiency in a magnetized region using the magnetic properties of magnetite (Fe₃O₄) and equations describing the magnetic forces acting on particles produced by an external cylindrical electromagnetic coil. A Eulerian-Lagrangian technique is implemented to resolve the hemodynamic flow and the motion of particles under the influence of a range of magnetic field strengths (B_r = 2T, 4T, 6T, and 8T). Particle diameter sizes of 10 nm to 4 µm in diameter were assessed. Two dimensionless numbers are also investigated a priori in this study to characterize relative effects of Brownian motion (BM), magnetic force-induced particle motion, and convective blood flow on particle motion. Similar to our previous works, the computational simulations demonstrate that the greatest particle capture efficiency results for particle diameters within the micron range, specifically in regions where flow separation and vortices are at a minimum. Additionally, it was observed that the capture efficiency of particles decreases substantially with smaller particle diameters, especially in the superparamagnetic regime. The highest capture efficiency observed for superparamagnetic particles was 99% with an 8T magnetic field strength and 95% with a 2T magnetic field strength when analyzing 100 nm particles. For 10 nm particles and an 8T magnetic field strength, the particle capture efficiency was 48%, and for a 2T magnetic field strength the particle capture efficiency was 33%. Furthermore, it was found that larger magnetic field strengths, large particle diameter sizes (1 µm and above), and slower blood flow velocity increase the particle capture efficiency. The key finding in this work is that favorable capture efficiencies for superparamagnetic particles were observed in the CoW model for weak fields (B_r < 4T) which demonstrates MDT as a possible viable treatment candidate for cardiovascular disease.

Nuanxinkang prevents the development of myocardial infarction-induced chronic heart failure by promoting PINK1/Parkin-mediated mitophagy

BACKGROUND

Mitochondrial dysfunction is an important pathological feature of chronic heart failure (CHF). Regulation of mitophagy can effectively maintain mitochondrial homeostasis and energy metabolism, thereby inhibiting the development of CHF. Nuanxinkang (NXK), a Chinese herbal compound preparation, has significant cardioprotective effects on CHF; however, its underlying mechanism on mitophagy has not been completely clarified. This research intended to investigate the mechanism of NXK in treating myocardial infarction (MI)-induced CHF.

METHODS

The left anterior descending coronary artery (LAD) ligation surgery was performed to establish an MI-induced CHF model in male C57BL/6 mice. From 1 day after surgery, mice were given NXK (0.41, 0.82 or 1.65 g/kg/d), Perindopril (PDPL, 0.607 mg/kg/d), or an equivalent amount of sterile water by gavage for 28 continuous days. Then, mice were examined for cardiac function, myocardial fibrosis, cardiomyocyte apoptosis, mitochondrial structure and mitophagy levels of cardiomyocytes, etc. In addition, a hypoxic injury model was created using HL-1 cardiomyocytes from wild-type (WT) mice. HL-1 cells were pretreated with or without NXK-containing serum. Mitochondrial function and mitophagy levels were examined in HL-1 cells.

RESULTS

In MI-induced CHF mice, cardiac dysfunction, severe cardiac remodeling, elevated levels of oxidative stress, reduced ATP levels, and inhibition of PINK1/Parkin-mediated mitophagy were observed. High-dose NXK treatment (1.65 g/kg/d) significantly improved myocardial energy metabolism, inhibited cardiac remodeling, improved cardiac function, and restored cardiac PINK1/Parkin-mediated mitophagy levels to some extent in MI mice. In vitro, elevated levels of mitochondrial reactive oxygen species (ROS) with impaired mitochondrial membrane potential (ΔΨm) were observed in hypoxic HL-1 cells. While NXK treatment significantly protected cardiomyocytes from hypoxia-induced mitochondrial dysfunction, which is consistent with the in vivo results. Further studies showed that NXK could increase PINK1/Parkin-mediated mitophagy levels in cardiomyocytes, which could be blocked by the mitophagy inhibitor Mdivi-1.

CONCLUSION

In conclusion, NXK could prevent cardiac mitochondrial dysfunction and improve cardiac function against MI-induced CHF by promoting Pink1/Parkin-mediated mitophagy, which represents a very prospective strategy for the treatment of CHF.

Perspectives on mitochondrial relevance in cardiac ischemia/reperfusion injury

Cardiovascular disease is the most common cause of death worldwide and in particular, ischemic heart disease holds the most considerable position. Even if it has been deeply studied, myocardial ischemia-reperfusion injury (IRI) is still a side-effect of the clinical treatment for several heart diseases: ischemia process itself leads to temporary damage to heart tissue and obviously the recovery of blood flow is promptly required even if it worsens the ischemic injury. There is no doubt that mitochondria play a key role in pathogenesis of IRI: dysfunctions of these important organelles alter cell homeostasis and survival. It has been demonstrated that during IRI the system of mitochondrial quality control undergoes alterations with the disruption of the complex balance between the processes of mitochondrial fusion, fission, biogenesis and mitophagy. The fundamental role of mitochondria is carried out thanks to the finely regulated connection to other organelles such as plasma membrane, endoplasmic reticulum and nucleus, therefore impairments of these inter-organelle communications exacerbate IRI. This review pointed to enhance the importance of the mitochondrial network in the pathogenesis of IRI with the aim to focus on potential mitochondria-targeting therapies as new approach to control heart tissue damage after ischemia and reperfusion process.

Targeting Mitochondrial Dynamics Proteins for the Development of Therapies for Cardiovascular Diseases

Cardiovascular diseases are one of the leading causes of death worldwide. The identification of new pathogenetic targets contributes to more efficient development of new types of drugs for the treatment of cardiovascular diseases. This review highlights the problem of mitochondrial dynamics disorders, in the context of cardiovascular diseases. A change in the normal function of mitochondrial dynamics proteins is one of the reasons for the development of the pathological state of cardiomyocytes. Based on this, therapeutic targeting of these proteins may be a promising strategy in the development of cardiac drugs. Here we will consider changes for each process of mitochondrial dynamics in cardiovascular diseases: fission and fusion of mitochondria, mitophagy, mitochondrial transport and biogenesis, and also analyze the prospects of the considered protein targets based on existing drug developments.

Potential antihypertensive mechanism of egg white-derived peptide QIGLF revealed by proteomic analysis

Previous work has shown that egg white-derived peptide QIGLF has significant in vivo antihypertensive activity. This study aimed to clarify the antihypertensive mechanisms of QIGLF on spontaneously hypertensive rats (SHRs) by a serum proteomic approach. Here, the tandem mass tag (TMT) quantitative proteomic was performed to discover serum protein changes in SHRs with QIGLF. As a result, SHRs with 4 weeks of QIGLF treatment have distinct serum protein expression profiles by principal component and Pearson's correlation coefficient analysis. Based on Gene Ontology (GO) annotation, oxygen transport and organelle fusion were found to be a regulated major biological process. Besides, aldosterone regulated sodium reabsorption, mitophagy, gap junction, and tight junction were significantly regulated based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. QIGLF might exert antihypertensive effects in the SHRs by inhibiting Na+ reabsorption and oxidative stress, restoring gap junction and tight junction.

Mitochondrial Genome Variants as a Cause of Mitochondrial Cardiomyopathy

Mitochondria are small double-membraned organelles responsible for the generation of energy used in the body in the form of ATP. Mitochondria are unique in that they contain their own circular mitochondrial genome termed mtDNA. mtDNA codes for 37 genes, and together with the nuclear genome (nDNA), dictate mitochondrial structure and function. Not surprisingly, pathogenic variants in the mtDNA or nDNA can result in mitochondrial disease. Mitochondrial disease primarily impacts tissues with high energy demands, including the heart. Mitochondrial cardiomyopathy is characterized by the abnormal structure or function of the myocardium secondary to genetic defects in either the nDNA or mtDNA. Mitochondrial cardiomyopathy can be isolated or part of a syndromic mitochondrial disease. Common manifestations of mitochondrial cardiomyopathy are a phenocopy of hypertrophic cardiomyopathy, dilated cardiomyopathy, and cardiac conduction defects. The underlying pathophysiology of mitochondrial cardiomyopathy is complex and likely involves multiple abnormal processes in the cell, stemming from deficient oxidative phosphorylation and ATP depletion. Possible pathophysiology includes the activation of alternative metabolic pathways, the accumulation of reactive oxygen species, dysfunctional mitochondrial dynamics, abnormal calcium homeostasis, and mitochondrial iron overload. Here, we highlight the clinical assessment of mtDNA-related mitochondrial cardiomyopathy and offer a novel hypothesis of a possible integrated, multivariable pathophysiology of disease.

Recent Advances on Drug Development and Emerging Therapeutic Agents Through Targeting Cellular Homeostasis for Ageing and Cardiovascular Disease

Ageing is a progressive physiological process mediated by changes in biological pathways, resulting in a decline in tissue and cellular function. It is a driving factor in numerous age-related diseases including cardiovascular diseases (CVDs). Cardiomyopathies, hypertension, ischaemic heart disease, and heart failure are some of the age-related CVDs that are the leading causes of death worldwide. Although individual CVDs have distinct clinical and pathophysiological manifestations, a disturbance in cellular homeostasis underlies the majority of diseases which is further compounded with aging. Three key evolutionary conserved signalling pathways, namely, autophagy, mitophagy and the unfolded protein response (UPR) are involved in eliminating damaged and dysfunctional organelle, misfolded proteins, lipids and nucleic acids, together these molecular processes protect and preserve cellular homeostasis. However, amongst the numerous molecular changes during ageing, a decline in the signalling of these key molecular processes occurs. This decline also increases the susceptibility of damage following a stressful insult, promoting the development and pathogenesis of CVDs. In this review, we discuss the role of autophagy, mitophagy and UPR signalling with respect to ageing and cardiac disease. We also highlight potential therapeutic strategies aimed at restoring/rebalancing autophagy and UPR signalling to maintain cellular homeostasis, thus mitigating the pathological effects of ageing and CVDs. Finally, we highlight some limitations that are likely hindering scientific drug research in this field.

Identification of small-molecule urea derivatives as PTPC modulators targeting the c subunit of F1/Fo-ATP synthase

Maintaining a high percentage of living and functional cells in those pathologies in which excessive cell death occurs, such as neurodegenerative disorders and cardiovascular diseases, is one of the most intriguing challenges in the field of biochemical research for drug discovery. Here, mitochondrial permeability transition-driven regulated cell death is the main mechanism of mitochondrial impairment and cell fate; this pathway is still lacking of satisfying pharmacological treatments to counteract its becoming; for this reason, it needs continuous and intense research to find new compounds as modulator of the permeability transition pore complex (PTPC) activity. In this study, we report the identification of small-molecule urea derivatives able to inhibit PTPC opening following calcium overload and selected for future use in cytoprotection.

Increase of Parkin and ATG5 plasmatic levels following perinatal hypoxic-ischemic encephalopathy

Brain injury at birth is an important cause of neurological and behavioral disorders. Hypoxic-ischemic encephalopathy (HIE) is a critical cerebral event occurring acutely or chronically at birth with high mortality and morbidity in newborns. Therapeutic strategies for the prevention of brain damage are still unknown, and the only medical intervention for newborns with moderate-to-severe HIE is therapeutic hypothermia (TH). Although the neurological outcome depends on the severity of the initial insult, emerging evidence suggests that infants with mild HIE who are not treated with TH have an increased risk for neurodevelopmental impairment; in the current clinical setting, there are no specific or validated biomarkers that can be used to both correlate the severity of the hypoxic insult at birth and monitor the trend in the insult over time. The aim of this work was to examine the presence of autophagic and mitophagic proteins in bodily fluids, to increase knowledge of what, early at birth, can inform therapeutic strategies in the first hours of life. This is a prospective multicentric study carried out from April 2019 to April 2020 in eight third-level neonatal intensive care units. All participants have been subjected to the plasma levels quantification of both Parkin (a protein involved in mitophagy) and ATG5 (involved in autophagy). These findings show that Parkin and ATG5 levels are related to hypoxic-ischemic insult and are reliable also at birth. These observations suggest a great potential diagnostic value for Parkin evaluation in the first 6 h of life.

Mitochondrial autophagy: molecular mechanisms and implications for cardiovascular disease

Mitochondria are highly dynamic organelles that participate in ATP generation and involve calcium homeostasis, oxidative stress response, and apoptosis. Dysfunctional or damaged mitochondria could cause serious consequences even lead to cell death. Therefore, maintaining the homeostasis of mitochondria is critical for cellular functions. Mitophagy is a process of selectively degrading damaged mitochondria under mitochondrial toxicity conditions, which plays an essential role in mitochondrial quality control. The abnormal mitophagy that aggravates mitochondrial dysfunction is closely related to the pathogenesis of many diseases. As the myocardium is a highly oxidative metabolic tissue, mitochondria play a central role in maintaining optimal performance of the heart. Dysfunctional mitochondria accumulation is involved in the pathophysiology of cardiovascular diseases, such as myocardial infarction, cardiomyopathy and heart failure. This review discusses the most recent progress on mitophagy and its role in cardiovascular disease.

The roles of the mitophagy inducer Danqi pill in heart failure: A new therapeutic target to preserve energy metabolism

BACKGROUND

Mitophagy can regulate mitochondrial homeostasis, preserve energy metabolism and cardiomyocytes survival effectively to restrain the development of heart failure (HF). Danqi Pill (DQP), composed of the dry roots of Salvia miltiorrhiza Bunge and Panax notoginseng, is included in the 2015 national pharmacopeia and effective in the clinical treatment of coronary heart diseases. Our previous studies have approved that DQP exerted remarkable cardioprotective effects on HF. However, the effect and mechanism of DQP on mitophagy have not been proved yet.

HYPOTHESIS/PURPOSE

We aim to explore whether DQP regulates mitophagy to protect against HF and to elucidate the in-depth mechanism.

STUDY DESIGN

The HF rat model for evaluating DQP's efficacy was established with left anterior descending coronary artery ligation. The oxygen-glucose deprivation-reperfusion-induced cardiomyocyte model was conducted to clarify the potential mechanism of DQP.

METHODS

The mitochondria-targeted fluorescent protein Keima (mt-Keima) was applied for detecting mitophagy flux. Co-immunofluorescence and co-immunoprecipitation were performed to detect protein co-localization. Flow cytometry for JC-1 and Annexin-FITC/PI staining was utilized for assessing mitochondrial activity and function.

RESULTS

In vivo, medium dose of DQP (1.5 g/kg) notably improved cardiac function and inhibited cardiac apoptosis in HF rats. Co-immunofluorescent staining of LC3B and TOM20 showed that DQP restored mitophagy. Further co-immunoprecipitation demonstrated that DQP increased the co-localization of FUNDC1 with either ULK1 or PGAM5. In vitro, DQP markedly protected mitochondrial membrane potential damage, reduced cardiomyocytes apoptosis, decreased the level of mitochondrial ROS, and increased the ATP level. Parallel with the in vitro results, DQP increased the interaction of FUNDC1 and LC3B, while knockdown of FUNDC1 diminished the interaction. Besides, Mt-Keima signaling detection further confirmed that DQP significantly promoted mitophagy. Intriguingly, knockdown of ULK1 or PGAM5 separately weakened rather than eliminated these effects of DQP on FUNDC1-mediated mitophagy, mitochondrial homeostasis and energy metabolism.

CONCLUSION

Our results demonstrated that DQP protected against HF by improving FUNDC1-mediated mitophagy to perverse energy metabolism through the coordinated regulation of ULK1 and PGAM5.

Optimal Nutrition Parameters for Neonates and Infants with Congenital Heart Disease

Congenital heart defects are known causes of malnutrition. Optimal nutritional management is paramount in improving short and long-term prognosis for neonates and infants with congenital heart malformations, as current strategies target preoperative and postoperative feeding requirements. Standardized enteral and/or parenteral feeding protocols, depending on the systemic implications of the cardiac defect, include the following common practices: diagnosing and managing feeding intolerance, choosing the right formula, and implementing a monitoring protocol. The latest guidelines from the American Society for Parenteral and Enteral Nutrition and the European Society of Paediatric and Neonatal Intensive Care, as well as a significant number of recent scientific studies, offer precious indications for establishing the best feeding parameters for neonates and infants with heart defects.

Some Insights into the Regulation of Cardiac Physiology and Pathology by the Hippo Pathway

The heart is one of the most fascinating organs in living beings. It beats up to 100,000 times a day throughout the lifespan, without resting. The heart undergoes profound anatomical, biochemical, and functional changes during life, from hypoxemic fetal stages to a completely differentiated four-chambered cardiac muscle. In the middle, many biological events occur after and intersect with each other to regulate development, organ size, and, in some cases, regeneration. Several studies have defined the essential roles of the Hippo pathway in heart physiology through the regulation of apoptosis, autophagy, cell proliferation, and differentiation. This molecular route is composed of multiple components, some of which were recently discovered, and is highly interconnected with multiple known prosurvival pathways. The Hippo cascade is evolutionarily conserved among species, and in addition to its regulatory roles, it is involved in disease by drastically changing the heart phenotype and its function when its components are mutated, absent, or constitutively activated. In this review, we report some insights into the regulation of cardiac physiology and pathology by the Hippo pathway.

Bone Marrow Mesenchymal Stem Cells and Their Derived Extracellular Vesicles Attenuate Non-Alcoholic Steatohepatitis-Induced Cardiotoxicity via Modulating Cardiac Mechanisms

Cardiovascular-disease (CVD)-related mortality has been fueled by the upsurge of non-alcoholic steatohepatitis (NASH). Mesenchymal stem cells (MSCs) were extensively studied for their reparative power in ameliorating different CVDs via direct and paracrine effects. Several reports pointed to the importance of bone marrow mesenchymal stem cells (BM-MSCs) as a reliable therapeutic approach for several CVDs. Nevertheless, their therapeutic potential has not yet been investigated in the cardiotoxic state that is induced by NASH. Thus, this study sought to investigate the molecular mechanisms associated with cardiotoxicity that accompany NASH. Besides, we aimed to comparatively study the therapeutic effects of bone-marrow mesenchymal-stem-cell-derived extracellular vesicles (BM-MSCs-EV) and BM-MSCs in a cardiotoxic model that is induced by NASH in rats. Rats were fed with high-fat diet (HFD) for 12 weeks. At the seventh week, BM-MSCs-EV were given a dose of 120 µg/kg i.v., twice a week for six weeks (12 doses per 6 weeks). Another group was treated with BM-MSCs at a dose of 1 × 10⁶ cell i.v., per rat once every 2 weeks for 6 weeks (3 doses per 6 weeks). BM-MSCs-EV demonstrated superior cardioprotective effects through decreasing serum cardiotoxic markers, cardiac hypoxic state (HIF-1) and cardiac inflammation (NF-κB p65, TNF-α, IL-6). This was accompanied by increased vascular endothelial growth factor (VEGF) and improved cardiac histopathological alterations. Both BM-MSCs-EV and BM-MSCs restored the mitochondrial antioxidant state through the upregulation of UCP2 and MnSOD genes. Besides, mitochondrial Parkin-dependent and -independent mitophagies were regained through the upregulation of (Parkin, PINK1, ULK1, BNIP3L, FUNDC1) and (LC3B). These effects were mediated through the regulation of pAKT, PI3K, Hypoxia, VEGF and NF-κB signaling pathways by an array of secreted microRNAs (miRNAs). Our findings unravel the potential ameliorative effects of BM-MSCs-EV as a comparable new avenue for BM-MSCs for modulating cardiotoxicity that is induced by NASH.

Mitophagy: Molecular Mechanisms, New Concepts on Parkin Activation and the Emerging Role of AMPK/ULK1 Axis

Mitochondria are multifunctional subcellular organelles essential for cellular energy homeostasis and apoptotic cell death. It is, therefore, crucial to maintain mitochondrial fitness. Mitophagy, the selective removal of dysfunctional mitochondria by autophagy, is critical for regulating mitochondrial quality control in many physiological processes, including cell development and differentiation. On the other hand, both impaired and excessive mitophagy are involved in the pathogenesis of different ageing-associated diseases such as neurodegeneration, cancer, myocardial injury, liver disease, sarcopenia and diabetes. The best-characterized mitophagy pathway is the PTEN-induced putative kinase 1 (PINK1)/Parkin-dependent pathway. However, other Parkin-independent pathways are also reported to mediate the tethering of mitochondria to the autophagy apparatuses, directly activating mitophagy (mitophagy receptors and other E3 ligases). In addition, the existence of molecular mechanisms other than PINK1-mediated phosphorylation for Parkin activation was proposed. The adenosine5'-monophosphate (AMP)-activated protein kinase (AMPK) is emerging as a key player in mitochondrial metabolism and mitophagy. Beyond its involvement in mitochondrial fission and autophagosomal engulfment, its interplay with the PINK1-Parkin pathway is also reported. Here, we review the recent advances in elucidating the canonical molecular mechanisms and signaling pathways that regulate mitophagy, focusing on the early role and spatial specificity of the AMPK/ULK1 axis.

Prompt Graft Cooling Enhances Cardioprotection during Heart Transplantation Procedures through the Regulation of Mitophagy

A complete and prompt cardiac arrest using a cold cardioplegic solution is routinely used in heart transplantation to protect the graft function. However, warm ischemic time is still inevitable during the procedure to isolate donor hearts in the clinical setting. Our knowledge of the mechanism changes prevented by cold storage, and how warm ischemia damages donor hearts, is extremely poor. The potential consequences of this inevitable warm ischemic time to grafts, and the underlying potential protective mechanism of prompt graft cooling, have been studied in order to explore an advanced graft protection strategy. To this end, a surgical procedure, including 10-15 min warm ischemic time during procurement, was performed in mouse models to mimic the clinical situation (Group I), and compared to a group of mice that had the procurement performed with prompt cooling procedures (Group II). The myocardial morphologic changes (including ultrastructure) were then assessed by electron and optical microscopy after 6 h of cold preservation. Furthermore, syngeneic heart transplantation was performed after 6 h of cold preservation to measure the graft heart function. An electron microscopy showed extensive damage, including hypercontracted myofibers with contraction bands, and damaged mitochondria that released mitochondrial contents in Group I mice, while similar patterns of damage were not observed in the mice from Group II. The results from both the electron microscopy and immunoblotting verified that cardiac mitophagy (protective mitochondrial autophagy) was present in the mice from Group II, but was absent in the mice from Group I. Moreover, the mice from Group II demonstrated faster rebeating times and higher beating scores, as compared to the mice from Group I. The pressure catheter system results indicated that the graft heart function was significantly more improved in the mice from Group II than in those from Group I, as demonstrated by the left ventricle systolic pressure (31.96 ± 6.54 vs. 26.12 ± 8.87 mmHg), the +dp/dt (815.6 ± 215.4 vs. 693.9 ± 153.8 mmHg/s), and the -dp/dt: (492.4 ± 92.98 vs. 418.5 ± 118.9 mmHg/s). In conclusion, the warm ischemic time during the procedure impaired the graft function and destroyed the activation of mitophagy. Thus, appropriate mitophagy activation has emerged as a promising therapeutic target that may be essential for graft protection and functional improvement during heart transplantation.

Emerging Role of Mitophagy in the Heart: Therapeutic Potentials to Modulate Mitophagy in Cardiac Diseases

The normal function of the mitochondria is crucial for most tissues especially for those that demand a high energy supply. Emerging evidence has pointed out that healthy mitochondrial function is closely associated with normal heart function. When these processes fail to repair the damaged mitochondria, cells initiate a removal process referred to as mitophagy to clear away defective mitochondria. In cardiomyocytes, mitophagy is closely associated with metabolic activity, cell differentiation, apoptosis, and other physiological processes involved in major phenotypic alterations. Mitophagy alterations may contribute to detrimental or beneficial effects in a multitude of cardiac diseases, indicating potential clinical insights after a close understanding of the mechanisms. Here, we discuss the current opinions of mitophagy in the progression of cardiac diseases, such as ischemic heart disease, diabetic cardiomyopathy, cardiac hypertrophy, heart failure, and arrhythmia, and focus on the key molecules and related pathways involved in the regulation of mitophagy. We also discuss recently reported approaches targeting mitophagy in the therapy of cardiac diseases.

Adding a "Notch" to Cardiovascular Disease Therapeutics: A MicroRNA-Based Approach

Dysregulation of the Notch pathway is implicated in the pathophysiology of cardiovascular diseases (CVDs), but, as of today, therapies based on the re-establishing the physiological levels of Notch in the heart and vessels are not available. A possible reason is the context-dependent role of Notch in the cardiovascular system, which would require a finely tuned, cell-specific approach. MicroRNAs (miRNAs) are short functional endogenous, non-coding RNA sequences able to regulate gene expression at post-transcriptional levels influencing most, if not all, biological processes. Dysregulation of miRNAs expression is implicated in the molecular mechanisms underlying many CVDs. Notch is regulated and regulates a large number of miRNAs expressed in the cardiovascular system and, thus, targeting these miRNAs could represent an avenue to be explored to target Notch for CVDs. In this Review, we provide an overview of both established and potential, based on evidence in other pathologies, crosstalks between miRNAs and Notch in cellular processes underlying atherosclerosis, myocardial ischemia, heart failure, calcification of aortic valve, and arrhythmias. We also discuss the potential advantages, as well as the challenges, of using miRNAs for a Notch-based approach for the diagnosis and treatment of the most common CVDs.

Autophagy-mitophagy induction attenuates cardiovascular inflammation in a murine model of Kawasaki disease vasculitis

Kawasaki disease (KD) is the leading cause of acquired heart disease among children. Murine and human data suggest that the NLRP3-IL-1β pathway is the main driver of KD pathophysiology. NLRP3 can be activated during defective autophagy/mitophagy. We used the Lactobacillus casei cell wall extract (LCWE) murine model of KD vasculitis, to examine the role of autophagy/mitophagy on cardiovascular lesion development. LCWE-injected mice had impaired autophagy/mitophagy and increased levels of ROS in cardiovascular lesions, together with increased systemic 8-OHdG release. Enhanced autophagic flux significantly reduced cardiovascular lesions in LCWE-injected mice, whereas autophagy blockade increased inflammation. Vascular smooth muscle cell specific deletion of Atg16l1 and global Parkin-/- significantly increased disease formation, supporting the importance of autophagy/mitophagy in this model. Ogg1-/- mice had significantly increased lesions with increased NLRP3 activity, whereas treatment with MitoQ, reduced vascular tissue inflammation, ROS production and systemic 8-OHdG release. Treatment with MN58b or Metformin (increasing AMPK and reducing ROS), resulted in decreased disease formation. Our results demonstrate that impaired autophagy/mitophagy and ROS-dependent damage exacerbate the development of murine KD vasculitis. This pathway can be efficiently targeted to reduce disease severity. These findings enhance our understanding of KD pathogenesis and identify novel therapeutic avenues for KD treatment.

Impairment of mitophagy and autophagy accompanies calcific aortic valve stenosis favoring cell death and the severity of disease

AIMS

In the last 15 years, some observations tried to shed light on the dysregulation of the cellular self-digestion process in calcific aortic valve stenosis (CAVS), but the results obtained remain still controversial. This work is aimed to definitively establish the trend of autophagy in patients affected by CAVS, to analyze the putative involvement of other determinants which impact on the mitochondrial quality control mechanisms and to explore possible avenues for pharmacological interventions in the treatment of CAVS.

METHODS AND RESULTS

This observational study, performed exclusively in ex vivo human samples (cells and serum), by using biochemical approaches and correlations with clinical data, describes new biological features of the calcified valve in terms of mitochondrial dysfunctions. In detail, we unveiled a significant deficiency in mitochondrial respiration and in ATP production coupled to increased production of lactates. In addition, mitochondrial population in the pathologic group is aged with significant alterations in biogenesis and mitophagy pathways. We are also reporting an updated view about autophagy accompanying the calcification process and advanced stages of the disease. We provided evidence for a rapamycin-based therapeutic strategy to revert the calcified phenotype to the wild type one.

CONCLUSIONS

Our data suggest that the Calcific Aortic Valve Stenosis phenotype is featured by defects in mitochondrial quality control mechanisms and that autophagy is not activated enough to counteract cell death and sustain cell functions. Thus, boosting autophagy and mitophagy from short to long-term revert quite all pathological phenotypes.

TRANSLATIONAL PERSPECTIVE

The findings from this study provide evidence for new molecular targets involving mitochondrial quality control mechanisms becoming dysregulated in CAVS. These pathways should be considered as amenable for a combination of new therapies in humans for three reasons: i) no pharmacological treatments are still available to slow down the development of advanced CAVS, ii) being calcification a recurring pathway and iii) the targets proposed are druggable by existing drugs used in the clinic for different purposes. This work also suggests a serum biomarker to be highly related to the stage of disease and the calcification grade of the valve.

Alpha-ketoglutarate ameliorates pressure overload-induced chronic cardiac dysfunction in mice

Increasing evidence indicates the involvement of myocardial oxidative injury and mitochondrial dysfunction in the pathophysiology of heart failure (HF). Alpha-ketoglutarate (AKG) is an intermediate metabolite of the tricarboxylic acid (TCA) cycle that participates in different cellular metabolic and regulatory pathways. The circulating concentration of AKG was found to decrease with ageing and is elevated after acute exercise and resistance exercise and in HF. Recent studies in experimental models have shown that dietary AKG reduces reactive oxygen species (ROS) production and systemic inflammatory cytokine levels, regulates metabolism, extends lifespan and delays the occurrence of age-related decline. However, the effects of AKG on HF remain unclear. In the present study, we explored the effects of AKG on left ventricular (LV) systolic function, the myocardial ROS content and mitophagy in mice with transverse aortic constriction (TAC). AKG supplementation inhibited pressure overload-induced myocardial hypertrophy and fibrosis and improved cardiac systolic dysfunction; in vitro, AKG decreased the Ang II-induced upregulation of β-MHC and ANP, reduced ROS production and cardiomyocyte apoptosis, and repaired Ang II-mediated injury to the mitochondrial membrane potential (MMP). These benefits of AKG in the TAC mice may have been obtained by enhanced mitophagy, which cleared damaged mitochondria. In summary, our study suggests that AKG improves myocardial hypertrophy remodelling, fibrosis and LV systolic dysfunction in the pressure-overloaded heart by promoting mitophagy to clear damaged mitochondria and reduce ROS production; thus, AKG may have therapeutic potential for HF.

Mitochondrial Modulations, Autophagy Pathways Shifts in Viral Infections: Consequences of COVID-19

Mitochondria are vital intracellular organelles that play an important role in regulating various intracellular events such as metabolism, bioenergetics, cell death (apoptosis), and innate immune signaling. Mitochondrial fission, fusion, and membrane potential play a central role in maintaining mitochondrial dynamics and the overall shape of mitochondria. Viruses change the dynamics of the mitochondria by altering the mitochondrial processes/functions, such as autophagy, mitophagy, and enzymes involved in metabolism. In addition, viruses decrease the supply of energy to the mitochondria in the form of ATP, causing viruses to create cellular stress by generating ROS in mitochondria to instigate viral proliferation, a process which causes both intra- and extra-mitochondrial damage. SARS-COV2 propagates through altering or changing various pathways, such as autophagy, UPR stress, MPTP and NLRP3 inflammasome. Thus, these pathways act as potential targets for viruses to facilitate their proliferation. Autophagy plays an essential role in SARS-COV2-mediated COVID-19 and modulates autophagy by using various drugs that act on potential targets of the virus to inhibit and treat viral infection. Modulated autophagy inhibits coronavirus replication; thus, it becomes a promising target for anti-coronaviral therapy. This review gives immense knowledge about the infections, mitochondrial modulations, and therapeutic targets of viruses.

Mitochondrial Bioenergetics and Dynamism in the Failing Heart

The heart is responsible for pumping blood, nutrients, and oxygen from its cavities to the whole body through rhythmic and vigorous contractions. Heart function relies on a delicate balance between continuous energy consumption and generation that changes from birth to adulthood and depends on a very efficient oxidative metabolism and the ability to adapt to different conditions. In recent years, mitochondrial dysfunctions were recognized as the hallmark of the onset and development of manifold heart diseases (HDs), including heart failure (HF). HF is a severe condition for which there is currently no cure. In this condition, the failing heart is characterized by a disequilibrium in mitochondrial bioenergetics, which compromises the basal functions and includes the loss of oxygen and substrate availability, an altered metabolism, and inefficient energy production and utilization. This review concisely summarizes the bioenergetics and some other mitochondrial features in the heart with a focus on the features that become impaired in the failing heart.

Cardiovascular Stents: A Review of Past, Current, and Emerging Devices

One of the leading causes of morbidity and mortality worldwide is coronary artery disease, a condition characterized by the narrowing of the artery due to plaque deposits. The standard of care for treating this disease is the introduction of a stent at the lesion site. This life-saving tubular device ensures vessel support, keeping the blood-flow path open so that the cardiac muscle receives its vital nutrients and oxygen supply. Several generations of stents have been iteratively developed towards improving patient outcomes and diminishing adverse side effects following the implanting procedure. Moving from bare-metal stents to drug-eluting stents, and recently reaching bioresorbable stents, this research field is under continuous development. To keep up with how stent technology has advanced in the past few decades, this paper reviews the evolution of these devices, focusing on how they can be further optimized towards creating an ideal vascular scaffold.

Relationship Between Autophagy and Metabolic Syndrome Characteristics in the Pathogenesis of Atherosclerosis

Atherosclerosis is the main cause of mortality in metabolic-related diseases, including cardiovascular disease and type 2 diabetes (T2DM). Atherosclerosis is characterized by lipid accumulation and increased inflammatory cytokines in the vascular wall, endothelial cell and vascular smooth muscle cell dysfunction and foam cell formation initiated by monocytes/macrophages. The characteristics of metabolic syndrome (MetS), including obesity, glucose intolerance, dyslipidemia and hypertension, may activate multiple mechanisms, such as insulin resistance, oxidative stress and inflammatory pathways, thereby contributing to increased risks of developing atherosclerosis and T2DM. Autophagy is a lysosomal degradation process that plays an important role in maintaining cellular metabolic homeostasis. Increasing evidence indicates that impaired autophagy induced by MetS is related to oxidative stress, inflammation, and foam cell formation, further promoting atherosclerosis. Basal and mild adaptive autophagy protect against the progression of atherosclerotic plaques, while excessive autophagy activation leads to cell death, plaque instability or even plaque rupture. Therefore, autophagic homeostasis is essential for the development and outcome of atherosclerosis. Here, we discuss the potential role of autophagy and metabolic syndrome in the pathophysiologic mechanisms of atherosclerosis and potential therapeutic drugs that target these molecular mechanisms.

Mitophagy in Human Diseases

Mitophagy is a selective autophagic process, essential for cellular homeostasis, that eliminates dysfunctional mitochondria. Activated by inner membrane depolarization, it plays an important role during development and is fundamental in highly differentiated post-mitotic cells that are highly dependent on aerobic metabolism, such as neurons, muscle cells, and hepatocytes. Both defective and excessive mitophagy have been proposed to contribute to age-related neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases, metabolic diseases, vascular complications of diabetes, myocardial injury, muscle dystrophy, and liver disease, among others. Pharmacological or dietary interventions that restore mitophagy homeostasis and facilitate the elimination of irreversibly damaged mitochondria, thus, could serve as potential therapies in several chronic diseases. However, despite extraordinary advances in this field, mainly derived from in vitro and preclinical animal models, human applications based on the regulation of mitochondrial quality in patients have not yet been approved. In this review, we summarize the key selective mitochondrial autophagy pathways and their role in prevalent chronic human diseases and highlight the potential use of specific interventions.

Cardioprotective Properties of Mannitol-Involvement of Mitochondrial Potassium Channels

Cardiac preconditioning (PC) and postconditioning (PoC) are powerful measures against the consequences of myocardial ischemia and reperfusion (I/R) injury. Mannitol-a hyperosmolar solution-is clinically used for treatment of intracranial and intraocular pressure or promotion of diuresis in renal failure. Next to these clinical indications, different organ-protective properties-e.g., perioperative neuroprotection-are described. However, whether Mannitol also confers cardioprotection via a pre- and/or postconditioning stimulus, possibly reducing consequences of I/R injury, remains to be seen. Therefore, in the present study we investigated whether (1) Mannitol-induced pre- and/or postconditioning induces myocardial infarct size reduction and (2) activation of mitochondrial ATP-sensitive potassium (mKATP) channels is involved in cardioprotection by Mannitol. Experiments were performed on isolated hearts of male Wistar rats via a pressure controlled Langendorff system, randomized into 7 groups. Each heart underwent 33 min of global ischemia and 60 min of reperfusion. Control hearts (Con) received Krebs-Henseleit buffer as vehicle only. Pre- and postconditioning was achieved by administration of 11 mmol/L Mannitol for 10 min before ischemia (Man-PC) or immediately at the onset of reperfusion (Man-PoC), respectively. In further groups, the mKATP channel blocker 5HD, was applied with and without Mannitol, to determine the potential underlying cardioprotective mechanisms. Primary endpoint was infarct size, determined by triphenyltetrazolium chloride staining. Mannitol significantly reduced infarct size both as a pre- (Man-PC) and postconditioning (Man-PoC) stimulus compared to control hearts (Man-PC: 31 ± 4%; Man-PoC: 35 ± 6%, each p < 0.05 vs. Con: 57 ± 9%). The mKATP channel inhibitor completely abrogated the cardioprotective effect of Mannitol-induced pre- (5HD-PC-Man-PC: 59 ± 8%, p < 0.05 vs. Man-PC) and postconditioning (5HD-PoC-Man-PoC: 59 ± 10% vs. p < 0.05 Man-PoC). Infarct size was not influenced by 5HD itself (5HD-PC: 60 ± 14%; 5HD-PoC: 54 ± 14%, each ns vs. Con). This study demonstrates that Mannitol (1) induces myocardial pre- and postconditioning and (2) confers cardioprotection via activation of mKATP channels.

Regulation of Mitochondrial Homeostasis by sAC-Derived cAMP Pool: Basic and Translational Aspects

In contrast to the traditional view of mitochondria being solely a source of cellular energy, e.g., the "powerhouse" of the cell, mitochondria are now known to be key regulators of numerous cellular processes. Accordingly, disturbance of mitochondrial homeostasis is a basic mechanism in several pathologies. Emerging data demonstrate that 3'-5'-cyclic adenosine monophosphate (cAMP) signalling plays a key role in mitochondrial biology and homeostasis. Mitochondria are equipped with an endogenous cAMP synthesis system involving soluble adenylyl cyclase (sAC), which localizes in the mitochondrial matrix and regulates mitochondrial function. Furthermore, sAC localized at the outer mitochondrial membrane contributes significantly to mitochondrial biology. Disturbance of the sAC-dependent cAMP pools within mitochondria leads to mitochondrial dysfunction and pathology. In this review, we discuss the available data concerning the role of sAC in regulating mitochondrial biology in relation to diseases.