Mitochondria play a central role in nonischemic cardiomyocyte necrosis: common to acute and chronic stressor states

Pheochromocytoma/paraganglioma-associated cardiomyopathy

Pheochromocytoma/paraganglioma (PPGL) are neuroendocrine tumors that frequently produce and release catecholamines. Catecholamine excess can manifest in several cardiovascular syndromes, including cardiomyopathy. PPGL-induced cardiomyopathies occur in up to 11% of cases and are most often associated with an adrenal pheochromocytoma (90%) and rarely with a paraganglioma derived from the sympathetic ganglia (10%). PPGL-associated cardiomyopathies can be chronic or acute, with takotsubo cardiomyopathy being the most often reported. These two types of PPGL-induced cardiomyopathy seem to have different pathophysiological backgrounds. Acute catecholaminergic stress inundates myocardial β-adrenoceptors and leads to left ventricle stunning and slight histological apoptosis. In chronic cardiomyopathy, prolonged catecholamine exposure leads to extended myocardial fibrosis, inflammation, and necrosis, and ultimately it causes dilated cardiomyopathy with a low ejection fraction. Sometimes, especially in cases associated with hypertension, hypertrophic cardiomyopathy can develop. The prognosis appears to be worse in chronic cases with a higher hospital mortality rate, higher cardiogenic shock rate at initial presentation, and lower left ventricular recovery rate after surgery. Therefore, establishing the correct diagnosis at an early stage of a PPGL is essential. This mini-review summarizes current data on pathophysiological pathways of cardiac damage caused by catecholamines, the clinical presentation of PPGL-induced cardiomyopathies, and discusses treatment options.

TCA cycle metabolites associated with adverse outcomes after acute coronary syndrome: mediating effect of renal function

Aims

To examine relationships of tricarboxylic acid (TCA) cycle metabolites with risk of cardiovascular events and mortality after acute coronary syndrome (ACS), and evaluate the mediating role of renal function in these associations.

Methods

This is a prospective study performed among 309 ACS patients who were followed for a mean of 6.7 years. During this period 131 patients developed major adverse cardiovascular events (MACE), defined as the composite of myocardial infarction, hospitalization for heart failure, and all-cause mortality, and 90 deaths were recorded. Plasma concentrations of citrate, aconitate, isocitrate, succinate, malate, fumarate, α-ketoglutarate and d/l-2-hydroxyglutarate were quantified using LC-tandem MS. Multivariable Cox regression models were used to estimate hazard ratios, and a counterfactual-based mediation analysis was performed to test the mediating role of estimated glomerular filtration rate (eGFR).

Results

After adjustment for traditional cardiovascular risk factors and medications, positive associations were found between isocitrate and MACE (HR per 1 SD, 1.25; 95% CI: 1.03, 1.50), and between aconitate, isocitrate, d/l-2-hydroxyglutarate and all-cause mortality (HR per 1 SD, 1.41; 95% CI: 1.07, 1.84; 1.58; 95% CI: 1.23, 2.02; 1.38; 95% CI: 1.14, 1.68). However, these associations were no longer significant after additional adjustment for eGFR. Mediation analyses demonstrated that eGFR is a strong mediator of these associations.

Conclusion

These findings underscore the importance of TCA metabolites and renal function as conjunctive targets in the prevention of ACS complications.

Myocardial infarction and oxidative damage in animal models: objective and expectations from the application of cysteine derivatives

Reactive oxygen species (ROS) and associated oxidative stress are the main contributors to pathophysiological changes following myocardial infarction (MI), which is the principal cause of death from cardiovascular disease. The glutathione (GSH)/glutathione peroxidase (GPx) system appears to be the main and most active cardiac antioxidant mechanism. Hence, enhancement of the myocardial GSH system might have protective effects in the setting of MI. It follows that by increasing antioxidant capacity, the heart will be able to reduce the damage associated with MI and even prevent/weaken the occurrence of oxidative stress, which is highly ranked among the factors responsible for the occurrence of acute MI. For these reasons, the primary goal of future investigations should be to address the effects of different antioxidative compounds and especially cysteine derivatives like N-acetyl cysteine (NAC) and L-2-oxothiazolidine-4-carboxylic acid (OTC) as precursors responsible for the enhancement of the GSH-related antioxidant system's capacity. It is assumed that this will lay down the basis for elucidation of the mechanisms throughout which applicable doses of OTC will manifest a potentially positive impact in the reduction of adverse effects of acute MI. The inclusion of OTC in the models for prediction of the distribution of oxygen in infarcted animal hearts can help to upgrade existing computational models. Such a model would be based on computational geometries of the heart, but the inclusion of biochemical redox features in addition to angiogenic therapy, despite improvement of the post-infarcted oxygenated outcome could enhance the accuracy of the predictive values of oxygenation.

The traditional uses, phytochemistry, and pharmacological properties of Paris L. (Liliaceae): A review

ETHNOPHARMACOLOGICAL RELEVANCE

Paris L. (Liliaceae) consisted of 33 species, of which the study focused on Paris polyphylla Smith, P. polyphylla var. chinensis (Franch.) Hara, and P. polyphylla Smith var. yunnanensis (Franch.) Hand. -Mazz. Due of course to the good effects of analgesia and hemostasis, it was traditionally used to treat trauma by folk herbalists.

AIM OF THIS REVIEW

This study summarized the traditional uses, distributions, phytochemical components, pharmacological properties, and toxicity evaluation of the genus Paris, and reviewed the economic value of cultivate P. polyphylla. This aim was that of providing a new and comprehensive recognition of these medicinal plants for the further utilization of Paris plants.

MATERIALS AND METHODS

The literature about traditional and folk uses of genus Paris was obtained from Duxiu Search, and China National Knowledge Infrastructure (CNKI). The other literature about genus Paris was searched online on Web of Science, PubMed, Google Scholar, Baidu Scholar, Scifinder database, and Springer research. The Scientific Database of China Plant Species (DCP) (http://db.kib.ac.cn/Default.aspx) databases were used to check the scientific names and provide species, varieties, and distribution of genus Paris. The botany studies information of genus Paris was available online from Plant Plus of China (www.iplant.cn). All the molecular structures of chemical compounds displayed in the text were produced by ChemBioDraw Ultra 14.0.

RESULTS

The plants of genus Paris, containing about 33 species and 15 varieties, are mainly distributed in Southwest China (Yunnan, Sichuan, and Guizhou provinces). More than 320 chemical components have been isolated from genus Paris since 2020, including steroidal saponins, C-21 steroids, phytosterols, insect hormones, pentacyclic triterpenes, flavonoids, and other compounds. Arrays of pharmacological investigations revealed that compounds and extracts of Paris species possess a wide spectrum of pharmacological effects, such as antitumor, cytotoxic, antimicrobial, antifungal, hemostatic, and anti-inflammatory activities. The studies about toxicity evaluation suggested that Rhizome Paridis had slight liver toxicity.

CONCLUSIONS

The dried rhizomes of P. polyphylla, P. polyphylla var. chinensis, and P. polyphylla var. yunnanensis were used to treat wound, bleeding, and stomachache, etc. in folk medicine. Phytochemistry researches showed that different species had pretty similarities especially in terms of chemical constituents. Pharmacological studies witnessed that Rhizome Paridis has various activities. Among these activities, steroidal saponins were the main active ingredients. Furthermore, an important aspect responsible for increasing interest in genus Paris is the use of antifertility-nonhormonal contraceptives by women. Also, the development of TCM (Traditional Chinese medicine) planting industry can improve the income of ethnic minorities and promote economic development.

Cerebral-Cardiac Syndrome and Diabetes: Cardiac Damage After Ischemic Stroke in Diabetic State

Cerebral-cardiac syndrome (CCS) refers to cardiac dysfunction following varying brain injuries. Ischemic stroke is strongly evidenced to induce CCS characterizing as arrhythmia, myocardial damage, and heart failure. CCS is attributed to be the second leading cause of death in the post-stroke stage; however, the responsible mechanisms are obscure. Studies indicated the possible mechanisms including insular cortex injury, autonomic imbalance, catecholamine surge, immune response, and systemic inflammation. Of note, the characteristics of the stroke population reveal a common comorbidity with diabetes. The close and causative correlation of diabetes and stroke directs the involvement of diabetes in CCS. Nevertheless, the role of diabetes and its corresponding molecular mechanisms in CCS have not been clarified. Here we conclude the features of CCS and the potential role of diabetes in CCS. Diabetes drives establish a “primed” inflammatory microenvironment and further induces severe systemic inflammation after stroke. The boosted inflammation is suspected to provoke cardiac pathological changes and hence exacerbate CCS. Importantly, as the key element of inflammation, NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome is indicated to play an important role in diabetes, stroke, and the sequential CCS. Overall, we characterize the corresponding role of diabetes in CCS and speculate a link of NLRP3 inflammasome between them.

Post-Stroke Cardiovascular Complications and Neurogenic Cardiac Injury: JACC State-of-the-Art Review

Over 1.5 million deaths worldwide are caused by neurocardiogenic syndromes. Furthermore, the consequences of deleterious brain-heart interactions are not limited to fatal complications. Cardiac arrhythmias, heart failure, and nonfatal coronary syndromes are also common. The brain-heart axis is implicated in post-stroke cardiovascular complications known as the stroke-heart syndrome, sudden cardiac death, and Takotsubo syndrome, among other neurocardiogenic syndromes. Multiple pathophysiological mechanisms with the potential to be targeted with novel therapies have been identified in the last decade. In the present state-of-the-art review, we describe recent advances in the understanding of anatomical and functional aspects of the brain-heart axis, cardiovascular complications after stroke, and a comprehensive pathophysiological model of stroke-induced cardiac injury.

Mitochondrial Ca2+ regulation in the etiology of heart failure: physiological and pathophysiological implications

Heart failure (HF) represents one of the leading causes of cardiovascular diseases with high rates of hospitalization, morbidity and mortality worldwide. Ample evidence has consolidated a crucial role for mitochondrial injury in the progression of HF. It is well established that mitochondrial Ca²⁺ participates in the regulation of a wide variety of biological processes, including oxidative phosphorylation, ATP synthesis, reactive oxygen species (ROS) generation, mitochondrial dynamics and mitophagy. Nonetheless, mitochondrial Ca²⁺ overload stimulates mitochondrial permeability transition pore (mPTP) opening and mitochondrial swelling, resulting in mitochondrial injury, apoptosis, cardiac remodeling, and ultimately development of HF. Moreover, mitochondria possess a series of Ca²⁺ transport influx and efflux channels, to buffer Ca²⁺ in the cytoplasm. Interaction at mitochondria-associated endoplasmic reticulum membranes (MAMs) may also participate in the regulation of mitochondrial Ca²⁺ homeostasis and plays an essential role in the progression of HF. Here, we provide an overview of regulation of mitochondrial Ca²⁺ homeostasis in maintenance of cardiac function, in an effort to identify novel therapeutic strategies for the management of HF.

Dietary Dityrosine Induces Mitochondrial Dysfunction by Diminished Thyroid Hormone Function in Mouse Myocardia

Oxidized tyrosine products (OTP) have been detected in commercial foods with high protein content, such as meat and milk products. OTP intake induces tissue oxidative stress and affects the normal activity of the hypothalamic-pituitary-thyroid axis (HPT). This study aims to investigate the effects of OTP and their main product, dityrosine (Dityr), on mouse myocardial function and myocardial energy metabolism. Mice received daily intragastric administration of either tyrosine (Tyr; 420 μg/kg body weight), Dityr (420 μg/kg body weight), or OTP (1909 μg/kg body weight) for 35 days. Additionally, H9c2 cells were incubated with various concentrations of Dityr for 72 h. We found that OTP and pure Dityr induced oxidative stress in growing mice and in H9c2 cells, resulting in a redox state imbalance, myocardial injury, mitochondrial dysfunction, and energy metabolism disorder. Dityr interferes with T3 regulation of the myocardium via the PI3K/AKT/GSK3β pathway, leading to myocardial mitochondrial damage and energy metabolism disorders. Food-borne OTP, especially Dityr, can disrupt thyroid hormone function in mouse myocardia leading to mitochondrial dysfunction, energy metabolism disorder, and oxidative stress.

Hydrogen Sulfide as a Potential Alternative for the Treatment of Myocardial Fibrosis

Harmful, stressful conditions or events in the cardiovascular system result in cellular damage, inflammation, and fibrosis. Currently, there is no targeted therapy for myocardial fibrosis, which is highly associated with a large number of cardiovascular diseases and can lead to fatal heart failure. Hydrogen sulfide (H₂S) is an endogenous gasotransmitter similar to nitric oxide and carbon monoxide. H₂S is involved in the suppression of oxidative stress, inflammation, and cellular death in the cardiovascular system. The level of H₂S in the body can be boosted by stimulating its synthesis or supplying it exogenously with a simple H₂S donor with a rapid- or slow-releasing mode, an organosulfur compound, or a hybrid with known drugs (e.g., aspirin). Hypertension, myocardial infarction, and inflammation are exaggerated when H₂S is reduced. In addition, the exogenous delivery of H₂S mitigates myocardial fibrosis caused by various pathological conditions, such as a myocardial infarct, hypertension, diabetes, or excessive β-adrenergic stimulation, via its involvement in a variety of signaling pathways. Numerous experimental findings suggest that H₂S may work as a potential alternative for the management of myocardial fibrosis. In this review, the antifibrosis role of H₂S is briefly addressed in order to gain insight into the development of novel strategies for the treatment of myocardial fibrosis.

Catecholamine-Induced Cardiomyopathy in Pheochromocytoma: How to Manage a Rare Complication in a Rare Disease?

Pheochromocytomas and paragangliomas (PHEOs) are rare neuroendocrine tumors. Clinical manifestations include different cardiovascular signs and symptoms, which are related to excessive secretion of catecholamines. Catecholamine-induced cardiomyopathy in PHEO (CICMPP) is a rare but dreaded complication of PHEO. Once patient is diagnosed with this condition, the prognosis is worse and a surgical risk is much higher than expected. This article focuses on how catecholamines affect the heart and the pathophysiologic mechanism of CICMPP. The cardiovascular responses to catecholamine depend mostly on which catecholamine is released as well as the amount of catecholamine that is released. The acute release of norepinephrine and epinephrine from PHEO increases heart rate, systemic vascular resistance, myocardial contractility, and reduces venous compliance. The excessive adrenergic stimulation by catecholamine results in severe vasoconstriction and coronary vasospasm, myocardial ischemia, and subsequently damage, and necrosis. Chronically elevated catecholamine levels lead to significant desensitization of cardiac β-adrenoceptors. The increased levels of the enzyme β-adrenoceptors kinase (βARK) in the heart seems to mediate these biochemical and physiological changes that are consistently correlated with attenuated responsiveness to catecholamine stimulation. Through these mechanisms different types of cardiomyopathy (CMP) can be formed. This review discusses extensively the 3 types of cardiomyopathies that can be present in a PHEO patient. It also provides the clinical presentation and diagnostic and therapeutic algorithm in managing patients with CICMPP.

The role of mitochondrial dysfunction in cardiovascular disease: a brief review

Cardiovascular disease (CVD) is a leading cause of mortality worldwide. Proper mitochondrial function is necessary in tissues and organs that are of high energy demand, including the heart. Mitochondria are very sensitive to nutrient and oxygen supply and undergo metabolic adaptation to the changing environment. In CVD, such an adaptation is impaired, which, in turn, leads to a progressive decline of the mitochondrial function associated with abnormalities in the respiratory chain and ATP synthesis, increased oxidative stress, and loss of the structural integrity of mitochondria. Uncoupling of the electron transport chain in dysfunctional mitochondria results in enhanced production of reactive oxygen species, depletion of cell ATP pool, extensive cell damage, and apoptosis of cardiomyocytes. Mitophagy is a process, during which cells clear themselves from dysfunctional and damaged mitochondria using autophagic mechanism. Deregulation of this process in the failing heart, accumulation of dysfunctional mitochondria makes the situation even more adverse. In cardiac pathology, aberrations of the activity of the respiratory chain and ATP production may be considered as a core of mitochondrial dysfunction. Indeed, therapeutic restoration of these key functional properties can be considered as a primary goal for improvement of mitochondrial dysfunction in CVD. Key messages Mitochondrial dysfunction plays a crucial role in cardiovascular disease pathogenesis. Cardiovascular disease is associated with altered mithochondrial biogenesis and clearance. In cardiovascular disease, impaired mitochondrial function results in decreased ATP production and enhanced ROS formation.

Cardiovascular Mitochondrial Dysfunction Induced by Cocaine: Biomarkers and Possible Beneficial Effects of Modulators of Oxidative Stress

Cocaine abuse has long been known to cause morbidity and mortality due to its cardiovascular toxic effects. The pathogenesis of the cardiovascular toxicity of cocaine use has been largely reviewed, and the most recent data indicate a fundamental role of oxidative stress in cocaine-induced cardiovascular toxicity, indicating that mitochondrial dysfunction is involved in the mechanisms of oxidative stress. The comprehension of the mechanisms involving mitochondrial dysfunction could help in selecting the most appropriate mitochondria injury biological marker, such as superoxide dismutase-2 activity and glutathionylated hemoglobin. The potential use of modulators of oxidative stress (mitoubiquinone, the short-chain quinone idebenone, and allopurinol) in the treatment of cocaine cardiotoxic effects is also suggested to promote further investigations on these potential mitochondria-targeted antioxidant strategies.

The Critical Roles of Zinc: Beyond Impact on Myocardial Signaling

Zinc has been considered as a vital constituent of proteins, including enzymes. Mobile reactive zinc (Zn(2+)) is the key form of zinc involved in signal transductions, which are mainly driven by its binding to proteins or the release of zinc from proteins, possibly via a redox switch. There has been growing evidence of zinc's critical role in cell signaling, due to its flexible coordination geometry and rapid shifts in protein conformation to perform biological reactions. The importance and complexity of Zn(2+) activity has been presumed to parallel the degree of calcium's participation in cellular processes. Whole body and cellular Zn(2+) levels are largely regulated by metallothioneins (MTs), Zn(2+) importers (ZIPs), and Zn(2+) transporters (ZnTs). Numerous proteins involved in signaling pathways, mitochondrial metabolism, and ion channels that play a pivotal role in controlling cardiac contractility are common targets of Zn(2+). However, these regulatory actions of Zn(2+) are not limited to the function of the heart, but also extend to numerous other organ systems, such as the central nervous system, immune system, cardiovascular tissue, and secretory glands, such as the pancreas, prostate, and mammary glands. In this review, the regulation of cellular Zn(2+) levels, Zn(2+)-mediated signal transduction, impacts of Zn(2+) on ion channels and mitochondrial metabolism, and finally, the implications of Zn(2+) in health and disease development were outlined to help widen the current understanding of the versatile and complex roles of Zn(2+).

The direct modulatory activity of zinc toward ion channels

The divalent zinc ion is a cation that plays an indispensable role as a structural constituent of numerous proteins, including enzymes and transcription factors. Recently, it has been suggested that zinc also plays a dynamic role in extracellular and intracellular signaling as well. Ion channels are pore-forming proteins that control the flow of specific ions across the membrane, which is important to maintain ion gradients. In this review, we outline the modulatory effect of zinc on the activities of several ion channels through direct binding of zinc into histidine, cysteine, aspartate, and glutamate moieties of channel proteins. The binding of zinc to ion channels results in the activation or inhibition of the channel due to conformational changes. These novel aspects of ion-channel activity modulation by zinc provide new insights into the physiological regulation of ion channels.

Pathophysiological mechanisms of catecholamine and cocaine-mediated cardiotoxicity

Overactivation of the sympatho-adrenergic system is an essential mechanism providing short-term adaptation to the stressful conditions of critical illnesses. In the same way, the administration of exogenous catecholamines is mandatory to support the failing circulation in acutely ill patients. In contrast to these short-term benefits, prolonged adrenergic stress is detrimental to the cardiovascular system by initiating a series of adverse effects triggering significant cardiotoxicity, whose pathophysiological mechanisms are complex and only partially elucidated. In addition to the development of myocardial oxygen supply/demand imbalance induced by the sustained activation of adrenergic receptors, catecholamines can damage cardiomyocytes by fostering mitochondrial dysfunction, via two main mechanisms. The first one is calcium overload, consecutive to β-adrenergic receptor-mediated activation of protein kinase A and subsequent phosphorylation of multiple Ca(2+)-cycling proteins. The second one is oxidative stress, primarily related to the transformation of catecholamines into "aminochromes," which undergo redox cycling in mitochondria to generate copious amounts of oxygen-derived free radicals. In turn, calcium overload and oxidative stress promote mitochondrial permeability transition and cardiomyocyte cell death, both via the apoptotic and necrotic pathways. Comparable mechanisms of myocardial toxicity, including marked oxidative stress and mitochondrial dysfunction, have been reported with the use of cocaine, a common recreational drug with potent sympathomimetic activity. The aim of the current review is to present in detail the pathophysiological processes underlying the development of catecholamine and cocaine-induced cardiomyopathy, as such conditions may be frequently encountered in the clinical practice of cardiologists and ICU specialists.

Autophagy of mitochondria: a promising therapeutic target for neurodegenerative disease

The autophagic process is the only known mechanism for mitochondrial turnover and it has been speculated that dysfunction of autophagy may result in mitochondrial error and cellular stress. Emerging investigations have provided new understanding of how autophagy of mitochondria (also known as mitophagy) is associated with cellular oxidative stress and its impact on neurodegeneration. This impaired autophagic function may be considered as a possible mechanism in the pathogenesis of several neurodegenerative disorders including Parkinson's disease, Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis, and Huntington disease. It can be suggested that autophagy dysfunction along with oxidative stress is considered main events in neurodegenerative disorders. New therapeutic approaches have now begun to target mitochondria as a potential drug target. This review discusses evidence supporting the notion that oxidative stress and autophagy are intimately associated with neurodegenerative disease pathogenesis. This review also explores new approaches that can prevent mitochondrial dysfunction, improve neurodegenerative etiology, and also offer possible cures to the aforementioned neurodegenerative diseases.

Ischaemic preconditioning preferentially increases protein S-nitrosylation in subsarcolemmal mitochondria

Nitric oxide (NO) and protein S-nitrosylation (SNO) have been shown to play important roles in ischaemic preconditioning (IPC)-induced acute cardioprotection. The majority of proteins that show increased SNO following IPC are localized to the mitochondria, and our recent studies suggest that caveolae transduce acute NO/SNO cardioprotective signalling in IPC hearts. Due to the close association between subsarcolemmal mitochondria (SSM) and the sarcolemma/caveolae, we tested the hypothesis that SSM, rather than the interfibrillar mitochondria (IFM), are major targets for NO/SNO signalling derived from caveolae-associated eNOS. Following either control perfusion or IPC, SSM and IFM were isolated from Langendorff perfused mouse hearts, and SNO was analysed using a modified biotin switch method with fluorescent maleimide fluors. In perfusion control hearts, the SNO content was higher in SSM compared with IFM (1.33 ± 0.19, ratio of SNO content Perf-SSM vs. Perf-IFM), and following IPC SNO content significantly increased preferentially in SSM, but not in IFM (1.72 ± 0.17 and 1.07 ± 0.04, ratio of SNO content IPC-SSM vs. Perf-IFM, and IPC-IFM vs. Perf-IFM, respectively). Consistent with these findings, eNOS, caveolin-3, and connexin-43 were detected in SSM, but not in IFM, and IPC resulted in a further significant increase in eNOS/caveolin-3 levels in SSM. Interestingly, we did not observe an IPC-induced increase in SNO or eNOS/caveolin-3 in SSM isolated from caveolin-3(-/-) mouse hearts, which could not be protected with IPC. In conclusion, these results suggest that SSM may be the preferential target of sarcolemmal signalling-derived post-translational protein modification (caveolae-derived eNOS/NO/SNO), thus providing an important role in IPC-induced cardioprotection.

Atrophic cardiomyocyte signaling in hypertensive heart disease

Cardinal pathological features of hypertensive heart disease (HHD) include not only hypertrophied cardiomyocytes and foci of scattered microscopic scarring, a footprint of prior necrosis, but also small myocytes ensnared by fibrillar collagen where disuse atrophy with protein degradation would be predicted. Whether atrophic signaling is concordant with the appearance of HHD and involves oxidative and endoplasmic reticulum (ER) stress remains unexplored. Herein, we examine these possibilities focusing on the left ventricle and cardiomyocytes harvested from hypertensive rats receiving 4 weeks aldosterone/salt treatment (ALDOST) alone or together with ZnSO₄, a nonvasoactive antioxidant, with the potential to attenuate atrophy and optimize hypertrophy. Compared with untreated age-/sex-/strain-matched controls, ALDOST was accompanied by (1) left ventricle hypertrophy with preserved systolic function; (2) concordant cardiomyocyte atrophy (<1000 μm²) found at sites bordering on fibrosis where they were reexpressing β-myosin heavy chain; and (3) upregulation of ubiquitin ligases, muscle RING-finger protein-1 and atrogin-1, and elevated 8-isoprostane and unfolded protein ER response with messenger RNA upregulation of stress markers. ZnSO₄ cotreatment reduced lipid peroxidation, fibrosis, and the number of atrophic myocytes, together with a further increase in cell area and width of atrophied and hypertrophied myocytes, and improved systolic function but did not attenuate elevated blood pressure. We conclude that atrophic signaling, concordant with hypertrophy, occurs in the presence of a reparative fibrosis and induction of oxidative and ER stress at sites of scarring where myocytes are atrophied. ZnSO₄ cotreatment in HHD with ALDOST attenuates the number of atrophic myocytes, optimizes size of atrophied and hypertrophied myocytes, and improves systolic function.

Clinical and echocardiographic correlates of serum copper and zinc in acute and chronic heart failure

AIM

Emerging evidence suggests a pathophysiological role of micronutrient dyshomeostasis in heart failure, including promotion of adverse remodeling and clinical deterioration. We sought to evaluate serum copper (Cu) and zinc (Zn) levels in acute (AHF) and chronic (CHF) heart failure.

METHODS

We studied 125 patients, 71 % male, aged 69 ± 11 years, 37 % with preserved left ventricular ejection fraction (LVEF ≥40 %) (HFPEF), including 81 with AHF and 44 with CHF; 21 healthy volunteers served as controls. Serum Cu and Zn levels were determined using air-acetylene flame atomic absorption spectrophotometry.

RESULTS

Serum Cu levels were significantly higher in AHF (p = 0.006) and CHF (p = 0.002) patients compared to controls after adjusting for age, gender and comorbidities, whereas they did not differ between AHF and CHF (p = 0.840). Additionally, serum Cu in patients with LVEF <40 % was significantly higher compared to both controls (p < 0.001) and HFPEF patients (p = 0.003). Serum Zn was significantly lower in AHF (p < 0.001) and CHF (p = 0.039) compared to control after adjusting for the above-mentioned variables. Moreover, serum Zn was significantly lower in AHF than in CHF (p = 0.015). In multiple linear regression, LVEF (p = 0.033) and E/e ratio (p = 0.006) were independent predictors of serum Cu in total heart failure population, while NYHA class (p < 0.001) and E/e ratio (p = 0.007) were independent predictors of serum Zn.

CONCLUSION

Serum Cu was increased both in AHF and CHF and correlated with LV systolic and diastolic function. Serum Zn, in contrast, was decreased both in AHF and CHF and independently predicted by clinical status and LV diastolic function.

Proteome analysis of subsarcolemmal cardiomyocyte mitochondria: a comparison of different analytical platforms

Mitochondria are complex organelles that play critical roles in diverse aspects of cellular function. Heart disease and a number of other pathologies are associated with perturbations in the molecular machinery of the mitochondria. Therefore, comprehensive, unbiased examination of the mitochondrial proteome represents a powerful approach toward system-level insights into disease mechanisms. A crucial aspect in proteomics studies is design of bioanalytical strategies that maximize coverage of the complex repertoire of mitochondrial proteins. In this study, we evaluated the performance of gel-based and gel-free multidimensional platforms for profiling of the proteome in subsarcolemmal mitochondria harvested from rat heart. We compared three different multidimensional proteome fractionation platforms: polymeric reversed-phase liquid chromatography at high pH (PLRP), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and isoelectric focusing (IEF) separations combined with liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS), and bioinformatics for protein identification. Across all three platforms, a total of 1043 proteins were identified. Among the three bioanalytical strategies, SDS-PAGE followed by LC-MS/MS provided the best coverage of the mitochondrial proteome. With this platform, 890 proteins with diverse physicochemical characteristics were identified; the mitochondrial protein panel encompassed proteins with various functional roles including bioenergetics, protein import, and mitochondrial fusion. Taken together, results of this study provide a large-scale view of the proteome in subsarcolemmal mitochondria from the rat heart, and aid in the selection of optimal bioanalytical platforms for differential protein expression profiling of mitochondria in health and disease.

African eggplant (Solanum anguivi Lam.) fruit with bioactive polyphenolic compounds exerts in vitro antioxidant properties and inhibits Ca(2+)-induced mitochondrial swelling

OBJECTIVE

To evaluate the antioxidant and radical scavenging activities of Solanum anguivi fruit (SAG) and its possible effect on mitochondrial permeability transition pore as well as mitochondrial membrane potential (ΔΨm) isolated from rat liver.

METHODS

Antioxidant activity of SAG was assayed by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), reducing power, iron chelation and ability to inhibit lipid peroxidation in both liver and brain homogenate of rats. Also, the effect of SAG on mitochondrial membrane potential and mitochondrial swelling were determined. Identification and quantification of bioactive polyphenolics was done by HPLC-DAD.

RESULTS

SAG exhibited potent and concentration dependent free radical-scavenging activity (IC50/DPPH=275.03±7.8 μg/mL). Reductive and iron chelation abilities also increase with increase in SAG concentration. SAG also inhibited peroxidation of cerebral and hepatic lipids subjected to iron oxidative assault. SAG protected against Ca(2+) (110 μmol/L)-induced mitochondrial swelling and maintained the ΔΨm. HPLC analysis revealed the presence of gallic acid [(17.54±0.04) mg/g], chlorogenic acid (21.90±0.02 mg/g), caffeic acid (16.64±0.01 mg/g), rutin [(14.71±0.03) mg/g] and quercetin [(7.39±0.05) mg/g].

CONCLUSIONS

These effects could be attributed to the bioactive polyphenolic compounds present in the extract. Our results suggest that SAG extract is a potential source of natural antioxidants that may be used not only in pharmaceutical and food industry but also in the treatment of diseases associated with oxidative stress.

Type 5 adenylyl cyclase increases oxidative stress by transcriptional regulation of manganese superoxide dismutase via the SIRT1/FoxO3a pathway

BACKGROUND

For reasons that remain unclear, whether type 5 adenylyl cyclase (AC5), 1 of 2 major AC isoforms in heart, is protective or deleterious in response to cardiac stress is controversial. To reconcile this controversy we examined the cardiomyopathy induced by chronic isoproterenol in AC5 transgenic (Tg) mice and the signaling mechanisms involved.

METHODS AND RESULTS

Chronic isoproterenol increased oxidative stress and induced more severe cardiomyopathy in AC5 Tg, as left ventricular ejection fraction fell 1.9-fold more than wild type, along with greater left ventricular dilation and increased fibrosis, apoptosis, and hypertrophy. Oxidative stress induced by chronic isoproterenol, detected by 8-OhDG was 15% greater, P=0.007, in AC5 Tg hearts, whereas protein expression of manganese superoxide dismutase (MnSOD) was reduced by 38%, indicating that the susceptibility of AC5 Tg to cardiomyopathy may be attributable to decreased MnSOD expression. Consistent with this, susceptibility of the AC5 Tg to cardiomyopathy was suppressed by overexpression of MnSOD, whereas protection afforded by the AC5 knockout (KO) was lost in AC5 KO×MnSOD heterozyous KO mice. Elevation of MnSOD was eliminated by both sirtuin and MEK inhibitors, suggesting both the SIRT1/FoxO3a and MEK/ERK pathway are involved in MnSOD regulation by AC5.

CONCLUSIONS

Overexpression of AC5 exacerbates the cardiomyopathy induced by chronic catecholamine stress by altering regulation of SIRT1/FoxO3a, MEK/ERK, and MnSOD, resulting in oxidative stress intolerance, thereby shedding light on new approaches for treatment of heart failure.

Role of oxidative stress in infectious diseases. A review

Oxidative stress plays a dual role in infections. Free radicals protect against invading microorganisms, and they can also cause tissue damage during the resulting inflammation. In the process of infection, there is generation of reactive species by myeloperoxidase, NADPH oxidase, and nitric oxide synthase. On the other hand, reactive species can be generated among others, by cytochrome P450, some metals, and xanthine oxidase. Some pathologies arising during infection can be attributed to oxidative stress and generation of reactive species in infection can even have fatal consequences. This article reviews the basic pathways in which reactive species can accumulate during infectious diseases and discusses the related health consequences.

Myofibroblast-mediated mechanisms of pathological remodelling of the heart

The syncytium of cardiomyocytes in the heart is tethered within a matrix composed principally of type I fibrillar collagen. The matrix has diverse mechanical functions that ensure the optimal contractile efficiency of this muscular pump. In the diseased heart, cardiomyocytes are lost to necrotic cell death, and phenotypically transformed fibroblast-like cells-termed 'myofibroblasts'-are activated to initiate a 'reparative' fibrosis. The structural integrity of the myocardium is preserved by this scar tissue, although at the expense of its remodelled architecture, which has increased tissue stiffness and propensity to arrhythmias. A persisting population of activated myofibroblasts turns this fibrous tissue into a living 'secretome' that generates angiotensin II and its type 1 receptor, and fibrogenic growth factors (such as transforming growth factor-β), all of which collectively act as a signal-transducer-effector signalling pathway to type I collagen synthesis and, therefore, fibrosis. Persistent myofibroblasts, and the resultant fibrous tissue they produce, cause progressive adverse myocardial remodelling, a pathological hallmark of the failing heart irrespective of its etiologic origin. Herein, we review relevant cellular, subcellular, and molecular mechanisms integral to cardiac fibrosis and consequent remodelling of atria and ventricles with a heterogeneity in cardiomyocyte size. Signalling pathways that antagonize collagen fibrillogenesis provide novel strategies for cardioprotection.