Role of superoxide, nitric oxide, and peroxynitrite in doxorubicin-induced cell death in vivo and in vitro

Understanding Anthracycline Cardiotoxicity From Mitochondrial Aspect

Anthracyclines, such as doxorubicin, represent one group of chemotherapy drugs with the most cardiotoxicity. Despite that anthracyclines are capable of treating assorted solid tumors and hematological malignancies, the side effect of inducing cardiac dysfunction has hampered their clinical use. Currently, the mechanism underlying anthracycline cardiotoxicity remains obscure. Increasing evidence points to mitochondria, the energy factory of cardiomyocytes, as a major target of anthracyclines. In this review, we will summarize recent findings about mitochondrial mechanism during anthracycline cardiotoxicity. In particular, we will focus on the following aspects: 1) the traditional view about anthracycline-induced reactive oxygen species (ROS), which is produced by mitochondria, but in turn causes mitochondrial injury. 2) Mitochondrial iron-overload and ferroptosis during anthracycline cardiotoxicity. 3) Autophagy, mitophagy and mitochondrial dynamics during anthracycline cardiotoxicity. 4) Anthracycline-induced disruption of cardiac metabolism.

New Insights in Early Detection of Anticancer Drug-Related Cardiotoxicity Using Perfusion and Metabolic Imaging

Cardio-oncology requires a good knowledge of the cardiotoxicity of anticancer drugs, their mechanisms, and their diagnosis for better management. Anthracyclines, anti-vascular endothelial growth factor (VEGF), alkylating agents, antimetabolites, anti-human epidermal growth factor receptor (HER), and receptor tyrosine kinase inhibitors (RTKi) are therapeutics whose cardiotoxicity involves several mechanisms at the cellular and subcellular levels. Current guidelines for anticancer drugs cardiotoxicity are essentially based on monitoring left ventricle ejection fraction (LVEF). However, knowledge of microvascular and metabolic dysfunction allows for better imaging assessment before overt LVEF impairment. Early detection of anticancer drug-related cardiotoxicity would therefore advance the prevention and patient care. In this review, we provide a comprehensive overview of the cardiotoxic effects of anticancer drugs and describe myocardial perfusion, metabolic, and mitochondrial function imaging approaches to detect them before over LVEF impairment.

Underlying the Mechanisms of Doxorubicin-Induced Acute Cardiotoxicity: Oxidative Stress and Cell Death

Cancer is a destructive disease that causes high levels of morbidity and mortality. Doxorubicin (DOX) is a highly efficient antineoplastic chemotherapeutic drug, but its use places survivors at risk for cardiotoxicity. Many studies have demonstrated that multiple factors are involved in DOX-induced acute cardiotoxicity. Among them, oxidative stress and cell death predominate. In this review, we provide a comprehensive overview of the mechanisms underlying the source and effect of free radicals and dependent cell death pathways induced by DOX. Hence, we attempt to explain the cellular mechanisms of oxidative stress and cell death that elicit acute cardiotoxicity and provide new insights for researchers to discover potential therapeutic strategies to prevent or reverse doxorubicin-induced cardiotoxicity.

[Nitric oxide donor nitrosorbide potentiates the antitumor effect of doxorubicin against experimental glioblastoma]

BACKGROUND

Doxorubicin is a well-known antitumor drug that is not employed for chemotherapy of brain tumors. Indeed, doxorubicin does not penetrate across the blood-brain barrier in therapeutic concentrations.

OBJECTIVE

To study the antitumor effect of doxorubicin combined with nitrosorbide on intracranial experimental glioblastoma 101/8 in rats.

MATERIAL AND METHODS

Male Wistar rats (n=86) with intracranial implanted glioblastoma 101/8 received doxorubicin (i.v. 1.5 mg/kg thrice) alone or in combination with nitrosorbide (i.v or orally, 0.5 mg/kg thrice) in 2, 5 and 8 days after implantation. Efficacy was assessed considering survival and brain tumor volume in 14 days after tumor implantation.

RESULTS

Combination of doxorubicin and nitrosorbide significantly increased survival (57% and 155%, respectively) and slowed down tumor growth (16±12 and 8±6 mm³, respectively) compared to doxorubicin alone. Effectiveness of nitrosorbide alone was trivial.

CONCLUSION

Nitric oxide donor nitrosorbide considerably potentiated the antitumor effect of doxorubicin against intracranial 101/8 glioblastoma in rats.

Morpho-functional indicators changes of rats’ myocardium in experimental doxorubicin-induced chronic heart failure and its pharmacological modulation with new 4-amino-1,2,4-triazole derivative

Bromide 1 - (β-phenylethyl)-4-amino-1,2,4-triazolium (Hypertril) has the properties of a beta-blocker and of NO-mimetic, is assigned to the IV class of toxicity. All these effects make Hypertril a promising drug for the treatment of cardiovascular diseases. The aim of this paper was to study the cardioprotective action of Hypertril in terms of the effect on the morpho-functional parameters of the myocardium in rats with experimental chronic heart failure (CHF). CHF was modeled on 80 white outbred rats weighing 190–220g by administering doxorubicin at a cumulative dose of 15 mg/kg. Hypertril and the reference drug metoprolol succinate were administered within 30 days after CHF modeling, intragastrically at doses of 3.5 mg/kg and 15 mg/kg. Morphometric analysis of the cellular structure of the myocardium was carried out on an Axioskop microscope (Zeiss, Germany), in an automatic mode using a macro program developed in a specialized programming environment VIDAS-2.5 (Kontron Elektronik, Germany). The administration of Hypertril to animals with CHF led to an increase in the density of nuclei of cardiomyocytes, the area of myocardiocyte nuclei, an increase in the nuclear cytoplasmic ratio and an increase in the concentration of RNA in the nuclei and cytoplasm of cardiomyocytes compared with the group of untreated animals, which indicated the presence of a pronounced cardioprotective effect in the drug candidate. In terms of such indicators as the density of surviving cardiomyocytes and the content of RNA in them, the nuclear-cytoplasmic ratio of Hypertril is significantly (p < 0.05) superior to metoprolol.

Reduction of doxorubicin-induced cytotoxicity and mitochondrial damage by betanin in rat isolated cardiomyocytes and mitochondria

Doxorubicin (DOX) is an anticancer drug which is used for treatment of several types of cancers. But the clinical use of doxorubicin is limited because of its cardiotoxicity and cardiomyopathy. Mitochondrial-dependent oxidative stress and cardiac inflammation appear to be involved in doxorubicin-induced cardiotoxicity. Betanin as a bioactive compound in Beetroot (Beta vulgaris L.) displays anti-radical, antioxidant gene regulatory and cardioprotective activities. In this current study, we investigated the protective effect of betanin on doxorubicin-induced cytotoxicity and mitochondrial-dependent oxidative stress in isolated cardiomyocytes and mitochondria. Isolated cardiomyocytes and mitochondria were treated with three concentrations of betanin (1, 5 and 10 µM) and doxorubicin (3.5 µM) for 6 h. The parameters of cellular and mitochondrial toxicity were analyzed using biochemical and flow cytometric methods. Our results showed a significant toxicity in isolated cardiomyocytes and mitochondria in presence of doxorubicin which was related to reactive oxygen species (ROS) formation, increase in malondialdehyde (MDA), increase in oxidation of GSH to GSSG, lysosomal/mitochondrial damages and mitochondrial swelling. While betanin pretreatment reverted doxorubicin-induced cytotoxicity and oxidative stress in isolated cardiomyocytes and mitochondria. These results suggest that betanin elicited a typical protective effect on doxorubicin-induced cytotoxicity and oxidative stress. It is possible that betanin could be used as a useful adjuvant in combination with doxorubicin chemotherapy for reduction of cardiotoxicity and cardiomyopathy.

Endoplasmic Reticulum Stress Promotes iNOS/NO and Influences Inflammation in the Development of Doxorubicin-Induced Cardiomyopathy

Doxorubicin (Dox) is known to cause heart failure in some cancer patients. Despite extensive studies over the past half century, the subcellular basis of Dox-induced cardiomyopathy (DIC) is still elusive. Earlier, we suggested that Dox causes a delayed activation of unfolded protein response (UPR) which may promote mitochondrial Bax activity leading to cardiomyocyte death. As a follow up, using NO donor, S-Nitroso-N-acetyl-d,l-penicillamine (SNAP), and/or NOS inhibitor, N(ω)-nitro-L-arginine methyl ester (L-NAME), we now show that endoplasmic reticulum (ER) stress promotes inflammation through iNOS/NO-induced TLR2 activation. In vivo Dox treatment increased mitochondrial iNOS to promote ER stress as there was an increase in Bip (Grp78) response, proapoptotic CHOP (DDIT3) and ER-mediated Caspase 12 activation. Increased iNOS activity is associated with an increase in TLR2 and TNF-α receptor associated factor 2 (TRAF2). These two together with NF-κB p105/50 expression and a synergistic support through ER stress, promote inflammatory response in the myocardium leading to cell death and ultimately fostering DIC conditions. In the presence of NOS inhibitor, such detrimental effects of Dox were inhibited, suggesting iNOS/NO as key mediators of Dox-induced inflammatory as well as apoptotic responses.

Cardiac inflammation and fibrosis following chemo/radiation therapy: mechanisms and therapeutic agents

The incidence of cardiovascular disorders is one of the most concerns among people who underwent cancer therapy. The heart side effects of cancer therapy may occur during treatment to some years after the end of treatment. Some epidemiological studies confirm that heart diseases are one of the most common reasons for mortality among patients that were received treatment for cancer. Experimental studies and also clinical investigations indicate that inflammatory changes such as pericarditis, myocarditis, and also fibrosis are key mechanisms of cardiac diseases following chemotherapy/radiotherapy. It seems that chronic oxidative stress, massive cell death, and chronic overproduction of pro-inflammatory and pro-fibrosis cytokines are the key mechanisms of cardiovascular diseases following cancer therapy. Furthermore, infiltration of inflammatory cells and upregulation of some enzymes such as NADPH Oxidases are a hallmark of heart diseases after cancer therapy. In the current review, we aim to explain how radiation or chemotherapy can induce inflammatory and fibrosis-related diseases in the heart. We will explain the cellular and molecular mechanisms of cardiac inflammation and fibrosis following chemo/radiation therapy, and then review some adjuvants to reduce the risk of inflammation and fibrosis in the heart.

Cardiotoxicity of Cancer Treatments: Focus on Anthracycline Cardiomyopathy

Significant progress has been made in developing new treatments and refining the use of preexisting ones against cancer. Their successful use and the longer survival of cancer patients have been associated with reports of new cardiotoxicities and the better characterization of the previously known cardiac complications. Immunotherapies with monoclonal antibodies against specific cancer-promoting genes, chimeric antigen receptor T cells, and immune checkpoint inhibitors have been developed to fight cancer cells, but they can also show off-target effects on the heart. Some of these cardiotoxicities are thought to be due to nonspecific immune activation and inflammatory damage. Unlike immunotherapy-associated cardiotoxicities which are relatively new entities, there is extensive literature on anthracycline-induced cardiomyopathy. Here, we provide a brief overview of the cardiotoxicities of immunotherapies for the purpose of distinguishing them from anthracycline cardiomyopathy. This is especially relevant as the expansion of oncological treatments presents greater diagnostic challenges in determining the cause of cardiac dysfunction in cancer survivors with a history of multiple cancer treatments including anthracyclines and immunotherapies administered concurrently or serially over time. We then provide a focused review of the mechanisms proposed to underlie the development of anthracycline cardiomyopathy based on experimental data mostly in mouse models. Insights into its pathogenesis may stimulate the development of new strategies to identify patients who are susceptible to anthracycline cardiomyopathy while permitting low cardiac risk patients to receive optimal treatment for their cancer.

MCC950 attenuates doxorubicin-induced myocardial injury in vivo and in vitro by inhibiting NLRP3-mediated pyroptosis

MCC950, an NLRP3 inflammasome inhibitor, displays multiple pharmacological properties. However, the protective potential and underlying mechanism of MCC950 against doxorubicin (DOX)-induced myocardial injury has not been well investigated yet. Herein, DOX-induced myocardial injury in mice and in H9c2 myocardial cells was investigated, and the protective effects and underlying mechanism of MCC950 were fully explored. The results showed that MCC950 co-treatment significantly improved myocardial function, inhibited inflammatory and myocardial fibrosis, and attenuated cardiomyocyte pyroptosis in DOX-treated mice. Mechanismly, MCC950 had the potential to inhibit DOX-induced the cleavage of NLRP3, ASC, Caspase-1, IL-18, IL-1β and GSDMD in vivo. Moreover, MCC950 co-treatment in vivo suppressed DOX-induced cytotoxicity as well as inflammatory and cardiomyocyte pyroptosis through the same molecular mechanism. Taken together, our findings validated that MCC950, an NLRP3 inflammasome inhibitor, has the potential to attenuate doxorubicin-induced myocardial injury in vivo and in vitro by inhibiting NLRP3-mediated pyroptosis.

Cardioprotective effect of allyl isothiocyanate in a rat model of doxorubicin acute toxicity

Doxorubicin (DOX) is an effective anthracycline chemotherapeutic drug. Nevertheless, the cardiotoxicity adverse effect restricts its clinical benefit. Allyl isothiocyanate (AITC) is a natural antioxidant and anti-inflammatory agent. In the present study, we investigated the effect of AITC on cardiotoxicity of DOX. Thirty-two adult male albino rats were divided into four groups; control, AITC, DOX, and AITC + DOX. AITC was administrated orally (25 mg/kg/day) for 7 days, and DOX was given as a single i.p. injection (15 mg/kg) on the third day. Mortality rate was observed during the experiment. Cardiac toxicity markers (lactate dehydrogenase (LDH), creatine kinase (CK-MB), and cardiac Troponin I (cTn-I)) were evaluated in serum samples obtained from all groups after 48 hours of DOX injection. DOX-treated group showed 40% mortality and a significant increase in cardiac enzymes. This increase was accompanied by degenerated cardiomyocytes, and inflammatory cells infiltrates. Interestingly, AITC administration alleviated myocardial oxidative stress induced by DOX as attenuated the increase in malondialdehyde (MDA), and nitric oxide (NO) while resulted in elevations of the antioxidant reduced glutathione (GSH) level as well as superoxide dismutase (SOD) activity. Furthermore, the inflammatory cytokine, TNF-α, was reduced upon administration of AITC with DOX. The cardio-protection of AITC is attributed to increase the expression of cytoprotective nuclear factor erythroid 2-related factor 2 (Nrf2). Subsequently, heme oxygenase 1 (HO-1) level was elevated by AITC to correct the oxidative stress induced by DOX in the heart. Accordingly, AITC ameliorated acute cardiotoxicity associated with DOX treatment via attenuation of oxidative stress and the induced-tissue inflammatory injury. Abbreviations: DOX: doxrubicin; Nrf2: nuclear factor erythroid 2-related factor 2; HO-1: heme oxygenase 1; AITC: ally isothiocyanate; MDA: malondialdehyde; SOD: superoxide dismutase; GSH: reduced glutathione; TNF-α: tumor necrosis factor alpha.

Cardiotoxicity of Antineoplastic Therapies and Applications of Induced Pluripotent Stem Cell-Derived Cardiomyocytes

The therapeutic landscape for the treatment of cancer has evolved significantly in recent decades, aided by the development of effective oncology drugs. However, many cancer drugs are often poorly tolerated by the body and in particular the cardiovascular system, causing adverse and sometimes fatal side effects that negate the chemotherapeutic benefits. The prevalence and severity of chemotherapy-induced cardiotoxicity warrants a deeper investigation of the mechanisms and implicating factors in this phenomenon, and a consolidation of scientific efforts to develop mitigating strategies. Aiding these efforts is the emergence of induced pluripotent stem cells (iPSCs) in recent years, which has allowed for the generation of iPSC-derived cardiomyocytes (iPSC-CMs): a human-based, patient-derived, and genetically variable platform that can be applied to the study of chemotherapy-induced cardiotoxicity and beyond. After surveying chemotherapy-induced cardiotoxicity and the associated chemotherapeutic agents, we discuss the use of iPSC-CMs in cardiotoxicity modeling, drug screening, and other potential applications. Improvements to the iPSC-CM platform, such as the development of more adult-like cardiomyocytes and ongoing advances in biotechnology, will only enhance the utility of iPSC-CMs in both basic science and clinical applications.

Protective Role of Vitamin B1 in Doxorubicin-Induced Cardiotoxicity in Rats: Focus on Hemodynamic, Redox, and Apoptotic Markers in Heart

Up until now, the specific mechanisms involved in doxorubicin (DOX)-induced cardiotoxicity have not been fully elucidated. Since thiamine deficiency is associated with myocardial dysfunction and it may lead to cardiomyopathy, we aimed to investigate whether thiamine (Vitamin B₁) treatment provides cardioprotection and modulates DOX mediated subchronic cardiotoxicity as well as to determine possible mechanisms of its effects. The study involved 48 Wistar albino rats divided into four groups: healthy non-treated rats and healthy rats treated with thiamine and DOX rats without treatment and DOX rats treated with thiamine. DOX was applied as a single i.p.injection (15mg/kg), while thiamine treatment lasted 7days (25mg/kg/dayi.p.). Before and after the treatment hemodynamic changes were monitored in vivo by echocardiography. When the protocol was completed, animals were sacrificed and rat hearts were isolated in order to evaluate parameters of cardiac oxidative stress [superoxide anion radical-O₂ ^-, hydrogen peroxide-H₂O₂, nitric oxide-NO^-, index of lipid peroxidation-thiobarbituric acid (TBA) reactive substances (TBARS), superoxide dismutase - SOD, catalase (CAT), and reduced glutathione-GSH] and apoptosis (Bax, Bcl-2, caspases). DOX treatment significantly reduced the ejection fraction, while thiamine treatment led to its minor increase in the DOX-treated group. In that sense, heart oxidative stress markers were significantly increased in DOX-treated rats, while therapeutic dose of thiamine decreased the levels of free radicals. Our study demonstrated the promising ameliorative effects of thiamine against DOX-induced cardiotoxicity through modulation of oxidative stress, suppression of apoptosis, and possibility to improve myocardial performance and morphometric structure of rats` hearts.

Doxorubicin-induced cardiotoxicity: An update on the molecular mechanism and novel therapeutic strategies for effective management

Doxorubicin (Dox) is a secondary metabolite of the mutated strain of Streptomyces peucetius var. Caesius and belongs to the anthracyclines family. The anti-cancer activity of Dox is mainly exerted through the DNA intercalation and inhibiting topoisomerase II enzyme in fast-proliferating tumors. However, Dox causes cumulative and dose-dependent cardiotoxicity, which results in increased risks of mortality among cancer patients and thus limiting its wide clinical applications. There are several mechanisms has been proposed for doxorubicin-induced cardiotoxicity and oxidative stress, free radical generation and apoptosis are most widely reported. Apart from this, other mechanisms are also involved in Dox-induced cardiotoxicity such as impaired mitochondrial function, a perturbation in iron regulatory protein, disruption of Ca2+ homeostasis, autophagy, the release of nitric oxide and inflammatory mediators and altered gene and protein expression that involved apoptosis. Dox also causes downregulation of DNA methyltransferase 1 (DNMT1) enzyme activity which leads to a reduction in the DNA methylation process. This hypomethylation causes dysregulation in the mitochondrial genes like peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1-alpha (PGC-1α), nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM) unit in the heart. Apart from DNA methylation, Dox treatment also alters the micro RNAs levels and histone deacetylase (HDAC) activity. Therefore, in the current review, we have provided a detailed update on the current understanding of the pathological mechanisms behind the well-known Dox-induced cardiotoxicity. Further, we have provided some of the most plausible pharmacological strategies which have been tested against Dox-induced cardiotoxicity.

Platelet-rich plasma inhibits Adriamycin-induced inflammation via blocking the NF-κB pathway in articular chondrocytes

Background

Previous studies showed that doxorubicin could lead to osteoarthritis (OA) by inducing chondrocyte inflammation and apoptosis. Besides, it is reported that platelet-rich plasma (PRP) could suppress the activation of inflammatory NF-κB signaling. Here, we aimed to determine whether PRP was able to exert a protective effect against doxorubicin-induced chondrocyte damages.

Methods

To determine whether PRP protects chondrocytes against destabilization of the medial meniscus (DMM)-induced osteoarthritis, mice were treated with PRP and doxorubicin, and the cartilage destruction was observed through Safranin O-fast green staining and osteoarthritis scoring. ELISA assay was used to check the release of TNF-α and ILs. In vitro, we treated chondrocytes with doxorubicin and PRP; CCK-8 was used to measure cell viability. Western blot, real-time PCR, and ELISA were applied to check apoptosis-related signaling and inflammation-associated factors.

Results

The results from the mouse model suggested that PRP attenuated doxorubicin-induced cartilage destruction in vivo. Doxorubicin promoted chondrocyte apoptosis while PRP ameliorated this damage. PRP inhibited doxorubicin-induced dysregulation of cell matrix-related factors, including SOX9, Col2A1, Col10A1, and Aggrecan, reduced protein levels of doxorubicin-induced inflammatory markers, COX-2, and iNOS, and blocked doxorubicin-induced phosphorylation of IκB and NF-κB in articular chondrocytes.

Conclusions

PRP improved doxorubicin-induced damage on chondrocytes. This research might provide a new theoretical basis for the clinical treatment of osteoarthritis caused by doxorubicin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00314-2.

An update of the molecular mechanisms underlying doxorubicin plus trastuzumab induced cardiotoxicity

Cardiotoxicity is a major side effect of the chemotherapeutic drug doxorubicin (Dox), which is further exacerbated when it is combined with trastuzumab, a standard care approach for Human Epidermal growth factor Receptor-type 2 (HER2) positive cancer patients. However, the molecular mechanisms of the underlying cardiotoxicity of this combination are still mostly elusive. Increased oxidative stress, impaired energetic substrate uses and topoisomerase IIB inhibition are among the biological processes proposed to explain Dox-induced cardiomyocyte dysfunction. Since cardiomyocytes express HER2, trastuzumab can also damage these cells by interfering with neuroregulin-1 signaling and mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)/Akt and focal adhesion kinase (FAK)-dependent pathways. Nevertheless, Dox and trastuzumab target other cardiac cell types, such as endothelial cells, fibroblasts, cardiac progenitor cells and leukocytes, which can contribute to the clinical cardiotoxicity observed. This review aims to summarize the current knowledge on the cardiac signaling pathways modulated by these two antineoplastic drugs highly used in the management of breast cancer, not only focusing on cardiomyocytes but also to broaden the knowledge of the potential impact on other cells found in the heart.

Anthracycline Associated Disturbances of Cardiovascular Homeostasis

Despite the dynamic progress of modern medicine, oncological and cardiovascular diseases (CVD) remain a severe economic burden worldwide. Therefore, the study of chemotherapeutic cardiotoxicity appears to be comprehensively demanded. Nowadays, pharmacological therapy in oncology has undoubtedly unprecedented development, but at the same time, the rates of cardiovascular complications of chemotherapy still remain unchanged. The well-established and highly effective, but at the same time, cardiotoxic anthracyclines have not lost their relevance. Furthermore, they remain indispensable components of an immense amount of chemotherapy regimens, such as AC, FAC, etc. Moreover, the anthracycline-containing chemotherapy regimens have become a standard of care in several cancer types. In the context of the above mentioned, the study of the pathophysiological mechanisms, biochemical aspects, and dynamics of the morphological remodeling of doxorubicin-induced cardiovascular homeostasis disturbances will enable finding new targets of pharmacological therapy, which either in the short or long perspectives, will have a beneficial effect, improving both the quality of life and prognosis of oncological patients. This article covers a versatile overview of the molecular mechanisms of doxorubicin-induced cardiotoxicity. The pathogenesis of cardiotoxicity assessment could help to explore specific molecular mechanisms that initiate cardiovascular alteration that may favorably affect the future development of targeted drugs that could prevent cardiovascular events in cancer patients.

Molecular mechanisms of anthracycline cardiovascular toxicity

Anthracyclines are effective chemotherapeutic agents, commonly used in the treatment of a variety of hematologic malignancies and solid tumors. However, their use is associated with a significant risk of cardiovascular toxicities and may result in cardiomyopathy and heart failure. Cardiomyocyte toxicity occurs via multiple molecular mechanisms, including topoisomerase II-mediated DNA double-strand breaks and reactive oxygen species (ROS) formation via effects on the mitochondrial electron transport chain, NADPH oxidases (NOXs), and nitric oxide synthases (NOSs). Excess ROS may cause mitochondrial dysfunction, endoplasmic reticulum stress, calcium release, and DNA damage, which may result in cardiomyocyte dysfunction or cell death. These pathophysiologic mechanisms cause tissue-level manifestations, including characteristic histopathologic changes (myocyte vacuolization, myofibrillar loss, and cell death), atrophy and fibrosis, and organ-level manifestations including cardiac contractile dysfunction and vascular dysfunction. In addition, these mechanisms are relevant to current and emerging strategies to diagnose, prevent, and treat anthracycline-induced cardiomyopathy. This review details the established and emerging data regarding the molecular mechanisms of anthracycline-induced cardiovascular toxicity.

[Doxorubicin directly induced fibrotic change of cardiac fibroblasts]

Doxorubicin (DOX)-induced cardiomyopathy has a poor prognosis. No early detection or effective treatment methods are available in clinical. The mechanisms of cardiotoxicity were considered as oxidative stress and apoptosis in cardiomyocytes. However, the effect of DOX on cardiac fibroblasts remains to be developed. We investigated the direct effect of DOX on the function of human cardiac fibroblasts (HCFs) independently of cell death pathway. Animal study showed that lower dose of DOX (4 mg/kg/week for 3 weeks, i.p.) than a toxic cumulate dose, induced perivascular fibrosis without cell death in hear of mice. DOX increased the protein expression of α-SMA (a marker of trans-differentiation) in HCFs culture cells, indicating that DOX promoted the trans-differentiation of HCFs into myofibroblast. DOX also increased the mRNA and protein expression of matrix metalloproteinase (MMP)-1 in less than 0.1 μM which did not induce cell apoptosis of HCFs cells via PI3K/Akt pathway in HCFs. DOX increased Interleukin-6 (IL-6) via transforming growth factor (TGF)-β/Smad pathway. In addition, DOX induced the mitochondrial damage and increased the expression of Interleukin-1 (IL-1) via stress-activated protein kinases (SAPK)/ c-Jun NH-2termial kinase (JNK). A peroxisome proliferator-activated receptor gamma (PPARγ) agonist, pioglitazone hydrochloride attenuated the expression of fibrotic marker such as α-SMA and galectin-3 and collagen1 via SAPK/JNK signaling. Pioglitazone also suppressed DOX-induced early fibrotic response in vivo. In conclusion, these findings suggested that low dose DOX induced reactive fibrotic change of cardiac fibroblasts via cell death-independent pathway. There may be potentially new mechanisms of DOX induced cardiotoxicity in clinical usage.

Noncoding RNAs in doxorubicin-induced cardiotoxicity and their potential as biomarkers and therapeutic targets

Anthracyclines, such as doxorubicin (DOX), are well known for their high efficacy in treating multiple cancers, but their clinical usage is limited due to their potential to induce fatal cardiotoxicity. Such detrimental effects significantly impact the overall physical condition or even induce the morbidity and mortality of cancer survivors. Therefore, it is extremely important to understand the mechanisms of DOX-induced cardiotoxicity to develop methods for the early detection of cytotoxicity and therapeutic applications. Studies have shown that many molecular events are involved in DOX-induced cardiotoxicity. However, the precise mechanisms are still not completely understood. Recently, noncoding RNAs (ncRNAs) have been extensively studied in a diverse range of regulatory roles in cellular physiological and pathological processes. With respect to their roles in DOX-induced cardiotoxicity, microRNAs (miRNAs) are the most widely studied, and studies have focused on the regulatory roles of long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), which have been shown to have significant functions in the cardiovascular system. Recent discoveries on the roles of ncRNAs in DOX-induced cardiotoxicity have prompted extensive interest in exploring candidate ncRNAs for utilization as potential therapeutic targets and/or diagnostic biomarkers. This review presents the frontier studies on the roles of ncRNAs in DOX-induced cardiotoxicity, addresses the possibility and prospects of using ncRNAs as diagnostic biomarkers or therapeutic targets, and discusses the possible reasons for related discrepancies and limitations of their use.

Protection against Doxorubicin-Induced Cardiotoxicity through Modulating iNOS/ARG 2 Balance by Electroacupuncture at PC6

Background

Doxorubicin (DOX) is a commonly used chemotherapeutic drug but is limited in clinical applications by its cardiotoxicity. Neiguan acupoint (PC6) is a well-recognized acupoint for the treatment of cardiothoracic disease. However, whether acupuncture at PC6 could be effective in preventing DOX-induced cardiotoxicity is still unknown.

Methods

A set of experiments were performed with myocardial cells, wild type, inducible nitric oxide synthase knockout (iNOS-/-), and myocardial-specific ablation arginase 2 (Myh6-ARG 2-/-) mice. We investigated the protective effect and the underlying mechanisms for electroacupuncture (EA) against DOX-induced cardiotoxicity by echocardiography, immunostaining, biochemical analysis, and molecular biotechnology in vivo and in vitro analysis.

Results

We found that DOX-mediated nitric oxide (NO) production was positively correlated with the iNOS level but has a negative correlation with the arginase 2 (ARG 2) level in both myocardial cells and tissues. Meanwhile, EA at PC6 alleviated cardiac dysfunction and cardiac hypertrophy in DOX-treated mice. EA at PC6 blocked the upregulation of NO production in accompanied with the downregulated iNOS and upregulated ARG 2 levels in myocardial tissue induced by DOX. Furthermore, knockout iNOS prevented cardiotoxicity and EA treatment did not cause the further improvement of cardiac function in iNOS-/- mice treated by DOX. In contrast, deficiency of myocardial ARG 2 aggravated DOX-induced cardiotoxicity and reduced EA protective effect.

Conclusion

These results suggest that EA treatment at PC6 can prevent DOX-induced cardiotoxicity through modulating NO production by modulating the iNOS/ARG 2 balance in myocardial cells.

The Potentials of Melatonin in the Prevention and Treatment of Bacterial Meningitis Disease

Bacterial meningitis (BM) is an acute infectious central nervous system (CNS) disease worldwide, occurring with 50% of the survivors left with a long-term serious sequela. Acute bacterial meningitis is more prevalent in resource-poor than resource-rich areas. The pathogenesis of BM involves complex mechanisms that are related to bacterial survival and multiplication in the bloodstream, increased permeability of blood-brain barrier (BBB), oxidative stress, and excessive inflammatory response in CNS. Considering drug-resistant bacteria increases the difficulty of meningitis treatment and the vaccine also has been limited to several serotypes, and the morbidity rate of BM still is very high. With recent development in neurology, there is promising progress for drug supplements of effectively preventing and treating BM. Several in vivo and in vitro studies have elaborated on understanding the significant mechanism of melatonin on BM. Melatonin is mainly secreted in the pineal gland and can cross the BBB. Melatonin and its metabolite have been reported as effective antioxidants and anti-inflammation, which are potentially useful as prevention and treatment therapy of BM. In bacterial meningitis, melatonin can play multiple protection effects in BM through various mechanisms, including immune response, antibacterial ability, the protection of BBB integrity, free radical scavenging, anti-inflammation, signaling pathways, and gut microbiome. This manuscript summarizes the major neuroprotective mechanisms of melatonin and explores the potential prevention and treatment approaches aimed at reducing morbidity and alleviating nerve injury of BM.

Early detection of doxorubicin-induced cardiotoxicity in rats by its cardiac metabolic signature assessed with hyperpolarized MRI

Doxorubicin (DOX) is a widely used chemotherapeutic agent that can cause serious cardiotoxic side effects culminating in congestive heart failure (HF). There are currently no clinical imaging techniques or biomarkers available to detect DOX-cardiotoxicity before functional decline. Mitochondrial dysfunction is thought to be a key factor driving functional decline, though real-time metabolic fluxes have never been assessed in DOX-cardiotoxicity. Hyperpolarized magnetic resonance imaging (MRI) can assess real-time metabolic fluxes in vivo. Here we show that cardiac functional decline in a clinically relevant rat-model of DOX-HF is preceded by a change in oxidative mitochondrial carbohydrate metabolism, measured by hyperpolarized MRI. The decreased metabolic fluxes were predominantly due to mitochondrial loss and additional mitochondrial dysfunction, and not, as widely assumed hitherto, to oxidative stress. Since hyperpolarized MRI has been successfully translated into clinical trials this opens up the potential to test cancer patients receiving DOX for early signs of cardiotoxicity.

Exploring the effectiveness of incorporating carbon nanotubes into bioengineered scaffolds to improve cardiomyocyte function

INTRODUCTION

Carbon nanotubes are effective in improving scaffolds to enhance cardiomyocyte function and hold great promise in the field of cardiac tissue engineering.

AREAS COVERED

A PubMed and Google Scholar search was performed to find relevant literature. 18 total studies were used as primary literature. The literature revealed that the incorporation of carbon nanotube into biocompatible scaffolds that mimic myocardial extracellular matrix enhanced the ability to promote cell functions by improving physical profiles of scaffolds. Several studies showed improved scaffold conductance, mechanical strength, improvements in cell properties such as viability, and beating behavior of cells grown on carbon nanotube incorporated scaffolds. Carbon nanotubes present a unique opportunity in the world of tissue engineering through reparation and regeneration of the myocardium, an otherwise irreparable tissue.

EXPERT OPINION

The high burden of cardiovascular disease has prompted research into cardiac tissue engineering applications. Carbon-nanotube incorporation into extracellular matrix-mimicking-scaffolds has shown to improve cardiomyocyte conductivity, viability, mechanical strength, beating behavior, and have protected them from damage to a certain degree. These are promising findings that have the potential of becoming the focus of future cardiac tissue engineering research.

Vitamin C: historical perspectives and heart failure

Vitamin C (Vit C) is an ideal antioxidant as it is easily available, water soluble, very potent, least toxic, regenerates other antioxidants particularly Vit E, and acts as a cofactor for different enzymes. It has received much attention due to its ability in limiting reactive oxygen species, oxidative stress, and nitrosative stress, as well as it helps to maintain some of the normal metabolic functions of the cell. However, over 140 clinical trials using Vit C in different pathological conditions such as myocardial infarction, gastritis, diabetes, hypertension, stroke, and cancer have yielded inconsistent results. Such a divergence calls for new strategies to establish practical significance of Vit C in heart failure or even in its prevention. For a better understanding of Vit C functioning, it is important to revisit its transport across the cell membrane and subcellular interactions. In this review, we have highlighted some historical details of Vit C and its transporters in the heart with a particular focus on heart failure in cancer chemotherapy.

Intravenous administration of cardiac progenitor cell-derived exosomes protects against doxorubicin/trastuzumab-induced cardiac toxicity

AIMS

Combined administration of anthracyclines (e.g. doxorubicin; Dox) and trastuzumab (Trz), a humanized anti-human epidermal growth factor receptor 2 (HER2; ErbB2), is an effective treatment for HER2-positive breast cancer. However, both agents are associated with cardiac toxicity. Human cardiac-resident mesenchymal progenitor cells (CPCs) secrete extracellular vesicles including nanosized exosomes which protect against myocardial ischaemia. Here, we investigated the effects of these exosomes using a novel model of Dox/Trz-mediated cardiotoxicity.

METHODS AND RESULTS

CPCs were derived from cardiac atrial appendage specimens from patients who underwent heart surgery for heart valve disease and/or ischaemic heart disease, and exosomes were purified from CPC conditioned media. Proteomics analyses revealed that CPC exosomes contained multiple proteins involved in redox processes. Dox/Trz induced a significant increase in reactive oxygen species (ROS) in rat cardiomyocytes, which was prevented by CPC exosomes. In vivo, rats received six doses of Dox (Days 1-11), followed by six doses of Trz (Days 19-28). Three doses of either exosomes or exosome suspension vehicle were injected intravenously on Days 5, 11, and 19 in the treatment and control groups, respectively. Dox/Trz induced myocardial fibrosis, CD68+ inflammatory cell infiltrates, inducible nitric oxide synthase expression, and left ventricular dysfunction. CPC exosomes prevented these effects. These vesicles were highly enriched in miR-146a-5p compared with human dermal fibroblast exosomes. Dox upregulated Traf6 and Mpo, two known miR-146a-5p target genes (which encode signalling mediators of inflammatory and cell death axes) in myocytes. CPC exosomes suppressed miR-146a-5p target genes Traf6, Smad4, Irak1, Nox4, and Mpo in Dox-treated cells. Specific silencing of miR-146a-5p abrogated exosome-mediated suppression of those genes leading to an increase in Dox-induced cell death.

CONCLUSIONS

Human CPC exosomes attenuate Dox-/Trz-induced oxidative stress in cardiomyocytes. Systemic administration of these vesicles prevents Dox/Trz cardiotoxicity in vivo. miR-146a-5p mediates some of the benefits of exosomes in this setting.

Doxorubicin Cytotoxicity in Differentiated H9c2 Cardiomyocytes: Evidence for Acute Mitochondrial Superoxide Generation

Although a mitochondrial redox-cycling superoxide-generating mechanism for the cardiotoxicity of doxorubicin was suggested from experiments with isolated mitochondria, its occurrence and contribution to cytotoxicity in intact cardiomyocytes is not fully established. Therefore, we determined the immediate and delayed effects of doxorubicin on the generation of reactive oxygen species (ROS) and cytotoxicity in differentiated H9c2 cardiomyocytes. Although relatively short incubations (3 or 6 h) with 1 or 5 µM doxorubicin did not acutely decrease cell survival, exposure to 5 µM doxorubicin for 3 h was sufficient to cause a significant delayed decrease in cell survival after an additional 24 h without doxorubicin. Mitochondrial superoxide generation was observed to increase within 30 min of incubation with 5 µM doxorubicin. Increased intracellular ROS generation, decreased mitochondrial metabolic activity, and decreased mitochondrial membrane potential (MMP) were observed after more extended periods (6-12 h). Overall, these observations support that the toxicity of doxorubicin to differentiated cardiomyocytes involves acute mitochondrial superoxide generation with subsequent intracellular ROS generation, mitochondrial dysfunction, and cell death.

Effect of Exercise Training on Exercise Tolerance and Level of Oxidative Stress for Head and Neck Cancer Patients Following Chemotherapy

Background

Chemotherapy decreases fitness performance via repression of cardiopulmonary function and oxidative stress. This study was designed to investigate whether exercise intervention could improve exercises capacity and reduce systemic oxidative stress in patients with head and neck (H&N) cancer receiving chemotherapy.

Methods

This is a single-center study. Forty-two H&N cancer patients who were undergoing chemotherapy were recruited in this study. An 8-week exercise intervention was performed by conducting the combination of aerobic and resistance exercise 3 days a week. The exercise training was conducted by a physiotherapist. The exercise capacity and exercise responses were measured from blood pressure (BP) and heart rate (HR). Oxidative stress markers from human plasma, such as total antioxidant capacity, 8-hydroxy-2'-deoxyguanosine, malondialdehyde, and carbonyl content, were tested by activity kits.

Results

We provide compelling evidence that exercise training ameliorated exercise responses and increased exercise capacity by repressing resting BP and increasing 1- and 3-min BP recovery. We also found the resting HR was reduced, and the 1- and 3-min HR recovery was increased after exercise training. In addition, the rating of perceived exertion after the peak exercise was reduced after exercise intervention. We also found that exercise training repressed oxidative stress markers by elevation of total antioxidant capacity and suppression of 8-OHd and carbonyl content in plasma.

Discussion

We clearly demonstrate that exercise can promote exercise capacity and reduce oxidative stress in H&N cancer patients receiving chemotherapy, which might guide new therapeutic approaches for cancer patients, especially those undergoing chemotherapy.

Nuclear cardiology in the context of multimodality imaging to detect cardiac toxicity from cancer therapeutics: Established and emerging methods

The complexity of cancer therapies has vastly expanded in the last decade, along with type and severity of cardiac toxicities associated with these treatments. Prevention of pre-clinical cardiotoxicity may improve cardiovascular outcomes and circumvent the decision to place life-sustaining chemotherapeutic agents on hold, making the early detection of cancer therapeutic related cardiac toxicity with non-invasive imaging essential to the care of these patients. There are several established methods of cardiac imaging in the areas of nuclear cardiology, echocardiography, computed tomography, and cardiac magnetic resonance imaging that are used to assess for cardiovascular toxicity of cancer treatments, with several methods under development. The following review will provide an overview of current and emerging imaging techniques in these areas.

The Role of Biomarkers in Cardio-Oncology

In the field of cardio-oncology, it is well recognised that despite the benefits of chemotherapy in treating and possibly curing cancer, it can cause catastrophic damage to bystander tissues resulting in a range of potentially of life-threatening cardiovascular toxicities, and leading to a number of damaging side effects including heart failure and myocardial infarction. Cardiotoxicity is responsible for significant morbidity and mortality in the long-term in oncology patients, specifically due to left ventricular dysfunction. There is increasing emphasis on the early use of biomarkers in order to detect the cardiotoxicity at a stage before it becomes irreversible. The most important markers of cardiac injury are cardiac troponin and natriuretic peptides, whilst markers of inflammation such as interleukin-6, C-reactive protein, myeloperoxidase, Galectin-3, growth differentiation factor-15 are under investigation for their use in detecting cardiotoxicity early. In addition, microRNAs, genome-wide association studies and proteomics are being studied as novel markers of cardiovascular injury or inflammation. The aim of this literature review is to discuss the evidence base behind the use of these biomarkers for the detection of cardiotoxicity.

Doxorubicin‑induced oxidative and nitrosative stress: Mitochondrial connexin 43 is at the crossroads

Oxidative stress is widely accepted as a key factor of doxorubicin (Doxo)-induced cardiotoxicity. There is evidence to indicate that nitrosative stress is involved in this process, and that Doxo interacts by amplifying cell damage. Mitochondrial connexin 43 (mitoCx43) can confer cardioprotective effects through the reduction of mitochondrial reactive oxygen species production during Doxo-induced cardiotoxicity. The present study aimed to evaluate the involvement of mitoCx43 in Doxo-induced nitrosative stress. Rat H9c2 cardiomyoblasts were treated with Doxo in the absence or presence of radicicol, an inhibitor of Hsp90, the molecular chaperone involved in Cx43 translocation to the mitochondria that underlies its role in cardioprotection. FACS analysis and RT-qPCR revealed that Doxo increased superoxide dismutase, and catalase gene and protein expression. As shown by hypodiploid nuclei and confirmed by western blot analysis, Doxo increased caspase 9 expression and reduced procaspase 3 levels, which induced cell death. Moreover, a significant increase in the activation of the NF-κB signaling pathway was observed. It is well known that the increased expression of inducible nitric oxide synthase results in nitric oxide overproduction, which then rapidly reacts with hydrogen peroxide or superoxide generated by the mitochondria, to form highly reactive and harmful peroxynitrite, which ultimately induces nitrotyrosine formation. Herein, these interactions were confirmed and increased effects were observed in the presence of radicicol. On the whole, the data of the present study indicate that an interplay between oxidative and nitrosative stress is involved in Doxo-induced cardiotoxicity, and that both aspects are responsible for the induction of apoptosis. Furthermore, it is demonstrated that the mechanisms that further increase mitochondrial super-oxide generation (e.g., the inhibition of Cx43 translocation into the mitochondria) significantly accelerate the occurrence of cell death.

Molecular Mechanisms of Cardiomyocyte Death in Drug-Induced Cardiotoxicity

Homeostatic regulation of cardiomyocytes plays a crucial role in maintaining the normal physiological activity of cardiac tissue. Severe cardiotoxicity results in cardiac diseases including but not limited to arrhythmia, myocardial infarction and myocardial hypertrophy. Drug-induced cardiotoxicity limits or forbids further use of the implicated drugs. Such drugs that are currently available in the clinic include anti-tumor drugs (doxorubicin, cisplatin, trastuzumab, etc.), antidiabetic drugs (rosiglitazone and pioglitazone), and an antiviral drug (zidovudine). This review focused on cardiomyocyte death forms and related mechanisms underlying clinical drug-induced cardiotoxicity, including apoptosis, autophagy, necrosis, necroptosis, pryoptosis, and ferroptosis. The key proteins involved in cardiomyocyte death signaling were discussed and evaluated, aiming to provide a theoretical basis and target for the prevention and treatment of drug-induced cardiotoxicity in the clinical practice.

Synthetic melanin nanoparticles as peroxynitrite scavengers, photothermal anticancer and heavy metals removal platforms

Melanin is a ubiquitous natural polyphenolic pigment with versatile applications including physiological functions. This polymeric material is found in a diversity of living organisms from bacteria to mammals. The biocompatibility and thermal stability of melanin nanoparticles make them good candidates to work as free radical scavengers and photothermal anticancer substrates. Research studies have identified melanin as an antioxidative therapeutic agent and/or reactive oxygen species (ROS) scavenger that includes neutralization of peroxynitrite. In addition, melanin nanoparticles have emerged as an anticancer photothermal platform that has the capability to kill cancer cells. Recently, melanin nanoparticles have been successfully used as chelating agents to purify water from heavy metals, such as hexavalent chromium. This review article highlights some selected aspects of cutting-edge melanin applications. Herein, we will refer to the recent literature that addresses melanin nanoparticles and its useful physicochemical properties as a hot topic in biomaterial science. It is expected that the techniques of Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and time-resolved Electron Paramagnetic Resonance (EPR) will have a strong impact on the full characterization of melanin nanoparticles and the subsequent exploration of their physiological and chemical mechanisms.

Nitrosative Stress and Its Association with Cardiometabolic Disorders

Reactive nitrogen species (RNS) are formed when there is an abnormal increase in the level of nitric oxide (NO) produced by the inducible nitric oxide synthase (iNOS) and/or by the uncoupled endothelial nitric oxide synthase (eNOS). The presence of high concentrations of superoxide anions (O₂⁻) is also necessary for their formation. RNS react three times faster than O₂⁻ with other molecules and have a longer mean half life. They cause irreversible damage to cell membranes, proteins, mitochondria, the endoplasmic reticulum, nucleic acids and enzymes, altering their activity and leading to necrosis and to cell death. Although nitrogen species are important in the redox imbalance, this review focuses on the alterations caused by the RNS in the cellular redox system that are associated with cardiometabolic diseases. Currently, nitrosative stress (NSS) is implied in the pathogenesis of many diseases. The mechanisms that produce damage remain poorly understood. In this paper, we summarize the current knowledge on the participation of NSS in the pathology of cardiometabolic diseases and their possible mechanisms of action. This information might be useful for the future proposal of anti-NSS therapies for cardiometabolic diseases.

Enhanced mitophagy mediated by the YAP/Parkin pathway protects against DOX-induced cardiotoxicity

The clinical usage of Doxorubicin (DOX) is limited due to its cardiotoxicity. Although the precise mechanism remains unclear, there is an increasing body of evidence that has demonstrated that mitophagy is responsible for DOX-induced cardiotoxicity. In the present study, Parkin, a key protein for mitophagy initiation, was revealed to be downregulated in mouse hearts and in H9c2 cells upon DOX treatment. Enforced expression of Parkin led to mitophagy activation and attenuated cell apoptosis in H9c2 cells. Parkin transgenic mice inhibited DOX-induced cardiotoxicity. Furthermore, Yes-associatd protein, as a transcription co-activator, regulated the gene expression of Parkin, and in turn Parkin overexpression protected against cell apoptosis induced by DOX treatment. Taken together, enhanced mitophagy mediated by YAP/Parkin pathway protects against DOX-induced cardiotoxicity in mouse heart. These studies revealed the complex pathological process of DOX-induced cardiotoxicity and provided novel insight into potential chemotherapy targets.

Tetrandrine Attenuated Doxorubicin-Induced Acute Cardiac Injury in Mice

Oxidative damage is closely involved in the development of doxorubicin- (DOX-) induced cardiotoxicity. It has been reported that tetrandrine can prevent the development of cardiac hypertrophy by suppressing reactive oxygen species- (ROS-) dependent signaling pathways in mice. However, whether tetrandrine could attenuate DOX-related cardiotoxicity remains unclear. To explore the protective effect of tetrandrine, mice were orally given a dose of tetrandrine (50 mg/kg) for 4 days beginning one day before DOX injection. To induce acute cardiac injury, the mice were exposed to a single intraperitoneal injection of DOX (15 mg/kg). The data in our study showed that tetrandrine prevented DOX-related whole-body wasting and heart atrophy, decreased markers of cardiac injury, and improved cardiac function in mice. Moreover, tetrandrine supplementation protected the mice against oxidative damage and myocardial apoptotic death. Tetrandrine supplementation also reduced ROS production and improved cell viability after DOX exposure in vitro. We also found that tetrandrine supplementation increased nuclear factor (erythroid-derived 2)-like 2 (Nrf2) expression and activity in vivo and in vitro. The protection of tetrandrine supplementation was blocked by Nrf2 deficiency in mice. In conclusion, our study found that tetrandrine could improve cardiac function and prevent the development of DOX-related cardiac injury through activation of Nrf2.

Naringenin Regulates Doxorubicin-Induced Liver Dysfunction: Impact on Oxidative Stress and Inflammation

Doxorubicin (Dox) is an operational and largely used anticancer drug, used to treat an array of malignancies. Nonetheless, its beneficial use is constrained due to its renal and hepatotoxicity dose dependently. Numerous research findings favor the use of antioxidants may impact Dox-induced liver injury/damage. In the current study, Wistar rats were given naringenin (50 and 100 mg/kg b.wt.) orally for 20 days as prophylactic dose, against the hepatotoxicity induced by single intraperitoneal injection of Dox (20 mg/kg b.wt.). Potency of naringenin against the liver damage caused by Dox was assessed by measuring malonyl aldehyde (MDA) as a by-product of lipid peroxidation, biochemical estimation of antioxidant enzyme system, reactive oxygen species (ROS) level, and inflammatory mediators. Naringenin-attenuated ROS production, ROS-induced lipid peroxidation, and replenished reduced antioxidant armory, namely, catalase (CAT), glutathione reductase (GR), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione (GSH). Naringenin similarly diminished expression of Cox-2 and levels of NF-κB and other inflammatory molecules induced by the Dox treatment. Histology added further evidence to the defensive effects of naringenin on Dox-induced liver damage. The outcomes of the current study reveal that oxidative stress and inflammation are meticulously linked with Dox-triggered damage, and naringenin illustrates the potential effect on Dox-induced hepatotoxicity probably through diminishing the oxidative stress and inflammation.

Modulatory effect of metformin on cardiotoxicity induced by doxorubicin via the MAPK and AMPK pathways

AIMS

Doxorubicin (DOX) is an effective anthracycline anticancer drug. However, the clinical usage of it is limited due to its severe cardiotoxicity side effects. Metformin (Met) is a kind of first-line antihyperglycemic drug which has a potential protective effect on the heart，it is often used for oral treatment of type 2 diabetes. In this study, we explored whether Met could attenuate cardiotoxicity induced by DOX.

MATERIALS AND METHODS

For the sake of exploring the Met protective effect and mechanism, we established the DOX-induced cardiotoxicity models both in H9C2 cells incubated with 5 μM DOX in vitro and Sprague-Dawley rats treated with 20 mg/kg cumulative dose of DOX.

KEY FINDINGS

Met is able to inhibit growth inhibition and apoptosis of H9C2 cells induced by DOX. The heart indexes of rats were examined to evaluate the Met cardiotoxicity protection. Met improved the abnormal indexes, serum markers of cardiac heart injury, echocardiography, electrocardiogram, cardiac pathology, cardiomyocyte apoptosis, and oxidative stress markers induced by DOX. Furthermore, in vivo and in vitro studies demonstrated that Met protected against DOX-induced increasing cleaved caspase-3 and Bax. Met also prevented the downregulation of Bcl-2, activated the AMPK pathway, and inhibited the MAPK pathway.

SIGNIFICANCE

Met showed protective effects on DOX-induced cardiotoxicity by reducing oxidative stress and apoptosis, as well as regulating AMPK and MAPK signaling pathways.

Cytoprotective Effects of Dinitrosyl Iron Complexes on Viability of Human Fibroblasts and Cardiomyocytes

Nitric oxide (NO) is an important signaling molecule that plays a key role in maintaining vascular homeostasis. Dinitrosyl iron complexes (DNICs) generating NO are widely used to treat cardiovascular diseases. However, the involvement of DNICs in the metabolic processes of the cell, their protective properties in doxorubicin-induced toxicity remain to be clarified. Here, we found that novel class of mononuclear DNICs with functional sulfur-containing ligands enhanced the cell viability of human lung fibroblasts and rat cardiomyocytes. Moreover, DNICs demonstrated remarkable protection against doxorubicin-induced toxicity in fibroblasts and in rat cardiomyocytes (H9c2 cells). Data revealed that the DNICs compounds modulate the mitochondria function by decreasing the mitochondrial membrane potential (ΔΨm). Results of flow cytometry showed that DNICs were not affected the proliferation, growth of fibroblasts. In addition, this study showed that DNICs did not affect glutathione levels and the formation of reactive oxygen species in cells. Moreover, results indicated that DNICs maintained the ATP equilibrium in cells. Taken together, these findings show that DNICs have protective properties in vitro. It was further suggested that DNICs may be uncouplers of oxidative phosphorylation in mitochondria and protective mechanism is mainly provided by the leakage of excess charge through the mitochondrial membrane. It is assumed that the DNICs have the therapeutic potential for treating cardiovascular diseases and for decreasing of chemotherapy-induced cardiotoxicity in cancer survivors.

Differential Effects of the Mitochondria-Active Tetrapeptide SS-31 (D-Arg-dimethylTyr-Lys-Phe-NH2) and Its Peptidase-Targeted Prodrugs in Experimental Acute Kidney Injury

The mitochondria-active tetrapeptide SS-31 can control oxidative tissue damage in kidney diseases. To investigate other potential beneficial nephroprotective effects of SS-31, in vivo murine models of acute tubular injury and glomerular damage were developed. Reduction of acute kidney injury was demonstrated in mice treated with SS-31. The expression of mRNAs involved in acute inflammatory and oxidative stress responses in the diseased kidneys confirmed that SS-31 could regulate these pathways in our in vivo models. Furthermore, ex vivo histoenzymography of mouse kidneys showed that aminopeptidase A (APA), the enzyme involved in the processing of angiotensin (Ang) II to Ang III, was induced in the diseased kidneys, and its activity was inhibited by SS-31. As the renin–angiotensin system (RAS) is a main regulator of kidney functions, the modulation of Ang receptors (ATR) and APA by SS-31 was further investigated using mRNAs extracted from diseased kidneys. Following acute tubular and/or glomerular damage, the expression of the AT₁R mRNA was upregulated, which could be selectively downregulated upon SS-31 administration to the animals. At the same time, SS-31 was able to increase the expression of the AT₂R, which may contribute to limit renal damage. Consequently, SS-31-based prodrugs were developed as substrates and/or inhibitors for APA and were screened using cells expressing high levels of APA, showing its selective regulation by α-Glu-SS-31. Thus, a link between SS-31 and the RAS opens new therapeutic implications for SS-31 in kidney diseases.

Major obstacles to doxorubicin therapy: Cardiotoxicity and drug resistance

Background

Doxorubicin is one of the most commonly prescribed and time-tested anticancer drugs. Although being considered as a first line drug in different types of cancers, the two main obstacles to doxorubicin therapy are drug-induced cardiotoxicity and drug resistance.

Method

The study utilizes systemic reviews on publications of previous studies obtained from scholarly journal databases including PubMed, Medline, Ebsco Host, Google Scholar, and Cochrane. The study utilizes secondary information obtained from health organizations using filters and keywords to sustain information relevancy. The study utilizes information retrieved from studies captured in the peer-reviewed journals on “doxorubicin-induced cardiotoxicity” and “doxorubicin resistance.”

Discussion and results

The exact mechanisms of cardiotoxicity are not known; various hypotheses are studied. Doxorubicin can lead to free radical generation in various ways. The commonly proposed underlying mechanisms promoting doxorubicin resistance are the expression of multidrug resistance proteins as well as other causes.

Conclusion

In this review, we have described the major obstacles to doxorubicin therapy, doxorubicin-induced cardiotoxicity as well as the mechanisms of cancer drug resistance and in following the treatment failures.

Blueberry extract attenuates doxorubicin-induced damage in H9c2 cardiac cells 1

The objective of this study was to analyze the cardioprotective roles of 3 wild blueberry genotypes and one commercial blueberry genotype by measuring markers of oxidative stress and cell death in H9c2 cardiac cells exposed to doxorubicin. Ripe berries of the 3 wild blueberry genotypes were collected from a 10-year-old clearcut forest near Nipigon, Ontario, Canada (49°1'39″N, 87°52'21″W), whereas the commercial blueberries were purchased from a local grocery store. H9c2 cardiac cells were incubated with 15 μg gallic acid equivalent/mL blueberry extract for 4 h followed by 5 μM doxorubicin for 4 h, and oxidative stress and active caspase 3/7 were analyzed. The surface area as well as total phenolic content was significantly higher in all 3 wild blueberry genotypes compared with the commercial species. Increase in oxidative stress due to doxorubicin exposure was attenuated by pre-treatment with all 3 types of wild blueberries but not by commercial berries. Furthermore, increase in caspase 3/7 activity was also attenuated by all 3 wild genotypes as well. These data demonstrate that wild blueberry extracts can attenuate doxorubicin-induced damage to H9c2 cardiomyocytes through reduction in oxidative stress and apoptosis, whereas the commercial blueberry had little effect.

Doxorubicin-Induced Cardiomyopathy in Children

Doxorubicin-induced cardiotoxicity in childhood cancer survivors is a growing problem. The population of patients at risk for cardiovascular disease is steadily increasing, as five-year survival rates for all types of childhood cancers continue to improve. Doxorubicin affects the developing heart differently from the adult heart and in a subset of exposed patients, childhood exposure leads to late, irreversible cardiomyopathy. Notably, the prevalence of late-onset toxicity is increasing in parallel with improved survival. By the year 2020, it is estimated that there will be 500,000 childhood cancer survivors and over 50,000 of them will suffer from doxorubicin-induced cardiotoxicity. The majority of the research to-date, concentrated on childhood cancer survivors, has focused mostly on clinical outcomes through well-designed epidemiological and retrospective cohort studies. Preclinical studies have elucidated many of the cellular mechanisms that elicit acute toxicity in cardiomyocytes. However, more research is needed in the areas of early- and late-onset cardiotoxicity and more importantly improving the scientific understanding of how other cells present in the cardiac milieu are impacted by doxorubicin exposure. The overall goal of this review is to succinctly summarize the major clinical and preclinical studies focused on doxorubicin-induced cardiotoxicity. As the prevalence of patients affected by doxorubicin exposure continues to increase, it is imperative that the major gaps in existing research are identified and subsequently utilized to develop appropriate research priorities for the coming years. Well-designed preclinical research models will enhance our understanding of the pathophysiology of doxorubicin-induced cardiotoxicity and directly lead to better diagnosis, treatment, and prevention. © 2019 American Physiological Society. Compr Physiol 9:905-931, 2019.

Definition of hidden drug cardiotoxicity: paradigm change in cardiac safety testing and its clinical implications

Unexpected cardiac adverse effects are the leading causes of discontinuation of clinical trials and withdrawal of drugs from the market. Since the original observations in the mid-90s, it has been well established that cardiovascular risk factors and comorbidities (such as ageing, hyperlipidaemia, and diabetes) and their medications (e.g. nitrate tolerance, adenosine triphosphate-dependent potassium inhibitor antidiabetic drugs, statins, etc.) may interfere with cardiac ischaemic tolerance and endogenous cardioprotective signalling pathways. Indeed drugs may exert unwanted effects on the diseased and treated heart that is hidden in the healthy myocardium. Hidden cardiotoxic effects may be due to (i) drug-induced enhancement of deleterious signalling due to ischaemia/reperfusion injury and/or the presence of risk factors and/or (ii) inhibition of cardioprotective survival signalling pathways, both of which may lead to ischaemia-related cell death and/or pro-arrhythmic effects. This led to a novel concept of 'hidden cardiotoxicity', defined as cardiotoxity of a drug that manifests only in the diseased heart with e.g. ischaemia/reperfusion injury and/or in the presence of its major comorbidities. Little is known on the mechanism of hidden cardiotoxocity, moreover, hidden cardiotoxicity cannot be revealed by the routinely used non-clinical cardiac safety testing methods on healthy animals or tissues. Therefore, here, we emphasize the need for development of novel cardiac safety testing platform involving combined experimental models of cardiac diseases (especially myocardial ischaemia/reperfusion and ischaemic conditioning) in the presence and absence of major cardiovascular comorbidities and/or cotreatments.

MiR-15b-5p is Involved in Doxorubicin-Induced Cardiotoxicity via Inhibiting Bmpr1a Signal in H9c2 Cardiomyocyte

The wide use of anthracyclines represented by doxorubicin (DOX) has benefited cancer patients, yet the clinical application is limited due to its cardiotoxicity. Although numerous evidences have supported a role of microRNAs (miRNAs) in DOX-induced myocardial damage, the exact etiology and pathogenesis remain largely obscure. In this study, we focused on the role of miR-15b-5p in DOX-induced cardiotoxicity. We employed a public miRNA and gene microarray to screen differentially expressed miRNAs (DEMs) and differentially expressed genes (DEGs) in rat cardiomyocytes, and 33 DEMs including miR-15b-5p and 237 DEGs including Bmpr1a and Gata4 were identified. The Gene ontology (GO) and pathway enrichment analysis of 237 DEGs indicated that the DEGs were mainly enriched in heart development and ALK pathway in cardiomyocyte which included the main receptor Bmpr1a and transcription factor Gata4. The up-regulated miR-15b-5p and down-regulated Bmpr1a and Gata4 mRNA expressions were further validated in H9c2 cardiomyocytes exposed to DOX. Moreover, the results showed overexpression of miR-15b-5p or inhibition of Bmpr1a may enhance the DOX-induced apoptosis, oxidative stress and mitochondria damage in H9c2 cardiomyocytes. The Bmpr1a was suggested as a potential target of miR-15b-5p by bioinformatics prediction. We further verified the negatively regulatory effect of miR-15b-5p on Bmpr1a signaling. Moreover, we also confirmed that overexpression of miR-15b-5p may exacerbate the DOX-induced apoptosis of H9c2 cardiomyocytes by affecting the protein expression ratio of Bcl-2/Bax and Akt activation, while this pro-apoptotic effect was able to be suppressed by Bmpr1a agonist. Collectively, the results suggest that miR-15b-5p is likely involved in doxorubicin-induced cardiotoxicity via inhibiting Bmpr1a signaling in H9c2 cardiomyocytes. Our study provides a novel insight for investigating DOX-induced cardiotoxicity.

Diverging effects of enalapril or eplerenone in primary prevention against doxorubicin-induced cardiotoxicity

Aims

Clinical studies suggest beneficial effects of renin-angiotensin system blockade for prevention of left ventricular (LV) dysfunction after chemotherapy. However, the efficacy of this strategy as primary prevention has been poorly studied. This study aimed at identifying the pathophysiological mechanisms by which mineralocorticoid receptor antagonism (MRA) or angiotensin converting enzyme inhibition (ACEi) provide protection against doxorubicin-induced cardiotoxicity (DIC) in mouse models of acute and chronic toxicity.

Methods and results

Acute DIC was induced by a single injection of Dox at 15 mg/kg and chronic DIC applied 5 injections of Dox at 4 mg/kg/week. MRA was achieved using eplerenone or cardiomyocyte-specific ablation of the MR gene in transgenic mice and ACEi using enalapril. Drugs were provided with the first dose of Dox and applied until the end of the study. In both model of DIC, Dox induced cardiac atrophy with decreased LV volume, reduced cardiomyocyte cell size, and cardiac dysfunction. In the acute model, neither MRA nor ACEi protected against these manifestations of DIC. In the chronic model, concomitant treatment with eplerenone did not protect against DIC and drastically increased plasma aldosterone levels and cardiac levels of angiotensin II type 1 receptor and of connective tissue growth factor (CTGF), as observed in acute DIC. Enalapril treatment in the chronic model, however, protected against cardiac dysfunction and cardiomyocyte atrophy and was associated with increased activation of the PI3K/AKT/mTOR pathway along with normal levels of CTGF.

Conclusion

Enalapril and eplerenone disparately impact on cellular signalling in DIC. Eplerenone, on top of Dox treatment was not protective and associated with increased levels of plasma aldosterone and of cardiac CTGF. In contrast, we show that primary prevention with enalapril preserves LV morphology and function in a clinically relevant model of chronic DIC, with increased stimulation of the PI3K/AKT/mTOR axis and normal CTGF levels suggesting potential therapeutic implications.