Molecular basis of anthracycline-induced cardiotoxicity and its prevention

AP39, a novel mitochondria-targeted hydrogen sulfide donor ameliorates doxorubicin-induced cardiotoxicity by regulating the AMPK/UCP2 pathway

Doxorubicin (DOX) is a broad-spectrum, highly effective antitumor agent; however, its cardiotoxicity has greatly limited its use. Hydrogen sulfide (H2S) is an endogenous gaseous transmitter that exerts cardioprotective effects via the regulation of oxidative stress and apoptosis and maintenance of mitochondrial function, among other mechanisms. AP39 is a novel mitochondria-targeted H2S donor that, at appropriate concentrations, attenuates intracellular oxidative stress damage, maintains mitochondrial function, and ameliorates cardiomyocyte injury. In this study, DOX-induced cardiotoxicity models were established using H9c2 cells and Sprague-Dawley rats to evaluate the protective effect of AP39 and its mechanisms of action. Both in vivo and in vitro experiments showed that DOX induces oxidative stress injury, apoptosis, and mitochondrial damage in cardiomyocytes and decreases the expression of p-AMPK/AMPK and UCP2. All DOX-induced changes were attenuated by AP39 treatment. Furthermore, the protective effect of AP39 was significantly attenuated by the inhibition of AMPK and UCP2. The results suggest that AP39 ameliorates DOX-induced cardiotoxicity by regulating the expression of AMPK/UCP2.

Diazoxide attenuates DOX-induced cardiotoxicity in cultured rat myocytes

Doxorubicin (DOX)-induced cardiotoxicity is a well known clinical problem, and many investigations have been made of its possible amelioration. We have investigated whether diazoxide (DIA), an agonist at mitochondrial ATP-sensitive potassium channels (mitoKATP), could reverse DOX-induced apoptotic myocardial cell loss, in cultured rat cardiomyocytes. The role of certain proteins in this pathway was also studied. The rat cardiomyocyte cell line (H9c2) was treated with DOX, and also co-treated with DOX and DIA, for 24 h. Distribution of actin filaments, mitochondrial membrane potential, superoxide dismutase (SOD) activity, total oxidant and antioxidant status (TOS and TAS, respectively), and some protein expressions, were assessed. DOX significantly decreased SOD activity, increased ERK1/2 protein levels, and depolarised the mitochondrial membrane, while DIA co-treatment inhibited such changes. DIA co-treatment ameliorated DOX-induced cytoskeletal changes via F-actin distribution and mitoKATP structure. Co-treatment also decreased ERK1/2 and cytochrome c protein levels. Cardiomyocyte loss due to oxidative stress-mediated apoptosis is a key event in DOX-induced cytotoxicity. DIA had protective effects on DOX-induced cardiotoxicity, via mitoKATP integrity, especially with elevated SUR2A levels; but also by a cascade including SOD/AMPK/ERK1/2. Therefore, DIA may be considered a candidate agent for protecting cardiomyocytes against DOX chemotherapy.

A prospective study to evaluate the efficacy and safety of vitamin E and levocarnitine prophylaxis against doxorubicin-induced cardiotoxicity in adult breast cancer patients

BACKGROUND

Doxorubicin induces acute and chronic cardiotoxicity. This study is aimed to evaluate the efficacy and safety of vitamin E and levocarnitine (EL) as cardioprotective agents against acute doxorubicin cardiotoxicity in female adult breast cancer patients.

METHODS

A prospective, randomized controlled study was conducted in patients treated with doxorubicin and cyclophosphamide (AC). Patients were randomly assigned to EL plus AC or AC alone for the duration of 4 cycles. Cardiac enzymes (B-type natriuretic peptide, creatine kinase, troponin I (Trop)) and cardiac events were monitored during treatment to evaluate the cardioprotective efficacy of EL.

RESULTS

Seventy-four patients were recruited and received four cycles of chemotherapy. The intervention group (n = 35) showed a significant reduction in both the B-type natriuretic peptide and creatine kinase cardiac enzymes compared to the control group (n = 39). The median (IQR) change for BNP was 0.80 (0.00-4.00) for IG versus 1.80 (0.40-3.60) for CG groups (p < 0.001); creatine kinase was -0.08 (-0.25-0.05) for IG versus 0.20 (0.05-0.50) for CG (p < 0.001). The addition of EL decreased the cardiac events by 24.2% (p = 0.02). All adverse events were tolerable and manageable.

CONCLUSION

This study supports the addition of EL as prophylaxis against acute doxorubicin cardiotoxicity and it was also very well tolerated by a majority of the patients. The co-administration of EL at higher doxorubicin (240 mg/m2) dose should be further investigated.

Anthracycline-induced cardiotoxicity: mechanisms, monitoring, and prevention

Anthracyclines are the most fundamental and important treatment of several cancers especially for lymphoma and breast cancer. However, their use is limited by a dose-dependent cardiotoxicity which may emerge early at the initiation of anthracycline administration or several years after termination of the therapy. A full comprehending of the mechanisms of anthracycline-induced cardiotoxicity, which has not been achieved and is currently under the efforts, is critical to the advance of developing effective methods to protect against the cardiotoxicity, as well as to early detect and treat it. Therefore, we review the recent progress of the mechanism underlying anthracycline-induced cardiotoxicity, as well as approaches to monitor and prevent this issue.

Metformin beyond an anti-diabetic agent: A comprehensive and mechanistic review on its effects against natural and chemical toxins

In addition to the anti-diabetic effect of metformin, a growing number of studies have shown that metformin has some exciting properties, such as anti-oxidative capabilities, anticancer, genomic stability, anti-inflammation, and anti-fibrosis, which have potent, that can treat other disorders other than diabetes mellitus. We aimed to describe and review the protective and antidotal efficacy of metformin against biologicals, chemicals, natural, medications, pesticides, and radiation-induced toxicities. A comprehensive search has been performed from Scopus, Web of Science, PubMed, and Google Scholar databases from inception to March 8, 2023. All in vitro, in vivo, and clinical studies were considered. Many studies suggest that metformin affects diseases other than diabetes. It is a radioprotective and chemoprotective drug that also affects viral and bacterial diseases. It can be used against inflammation-related and apoptosis-related abnormalities and against toxins to lower their effects. Besides lowering blood sugar, metformin can attenuate the effects of toxins on body weight, inflammation, apoptosis, necrosis, caspase-3 activation, cell viability and survival rate, reactive oxygen species (ROS), NF-κB, TNF-α, many interleukins, lipid profile, and many enzymes activity such as catalase and superoxide dismutase. It also can reduce the histopathological damages induced by many toxins on the kidneys, liver, and colon. However, clinical trials and human studies are needed before using metformin as a therapeutic agent against other diseases.

miR-21-5p prevents doxorubicin-induced cardiomyopathy by downregulating BTG2

Cardiomyocyte apoptosis has been characterized as one of the major mechanisms underlying doxorubicin (DOX)-induced cardiomyopathy. MicroRNA-21-5p (miR-21-5p) was reported to mitigate ischemia-induced cardiomyocyte apoptosis and cardiac injury. However, to our knowledge, the functional role of miR-21-5p in DOX-induced cardiomyopathy is unclear. In this study, we explored the role of miR-21-5p in DOX-induced cardiac injury. The expression level of miR-21-5p was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Dual luciferase reporter assay was used to verify the potential target gene of miR-21-5p. The apoptosis rate of NRCMs was detected by TUNEL staining assay. Western blot analysis was used to detect the protein expression levels of Bax, Bcl-2, Caspase3, cleaved-Caspase3 and BTG2. For animal studies, mice were injected with AAV9-miR-21-5p or AAV9-Empty viruses, and treated with DOX at a dose of 5 mg/kg per week through intraperitoneally administration. After 4 weeks of DOX treatment, mice were subjected to echocardiography to measure the left ventricular ejection fraction (EF) and fractional shortening (FS). Results showed that miR-21-5p was upregulated in both DOX-treated primary cardiomyocytes and mouse heart tissues. Interestingly, enhanced miR-21-5p expression inhibited DOX-induced cardiomyocyte apoptosis and oxidative stress, while decreased miR-21-5p expression promoted cardiomyocyte apoptosis and oxidative stress. Furthermore, cardiac overexpression of miR-21-5p protected against DOX-induced cardiac injury. The mechanistic study indicated that BTG2 was a target gene of miR-21-5p. The anti-apoptotic effect of miR-21-5p could be inhibited by BTG2 overexpression. Conversely, inhibition of BTG2 rescued the pro-apoptotic effect of miR-21-5p inhibitor. Taken together, our study showed that miR-21-5p could prevent DOX-induced cardiomyopathy by downregulating BTG2.

Recent progress in DNA methyltransferase inhibitors as anticancer agents

DNA methylation mediated by DNA methyltransferase is an important epigenetic process that regulates gene expression in mammals, which plays a key role in silencing certain genes, such as tumor suppressor genes, in cancer, and it has become a promising therapeutic target for cancer treatment. Similar to other epigenetic targets, DNA methyltransferase can also be modulated by chemical agents. Four agents have already been approved to treat hematological cancers. In order to promote the development of a DNA methyltransferase inhibitor as an anti-tumor agent, in the current review, we discuss the relationship between DNA methylation and tumor, the anti-tumor mechanism, the research progress and pharmacological properties of DNA methyltransferase inhibitors, and the future research trend of DNA methyltransferase inhibitors.

Idarubicin combats abiraterone and enzalutamide resistance in prostate cells via targeting XPA protein

Although second-generation therapies like abiraterone (ABI) and enzalutamide (ENZ) benefit patients with castration-resistant prostate cancer (CRPC), drug resistance frequently occurs, eventually resulting in therapy failure. In this study, we used two libraries, FDA-approved drug library and CRISP/Cas9 knockout (GeCKO) library to screen for drugs that overcome treatment resistance and to identify the potential drug-resistant genes involved in treatment resistance. Our screening results showed that the DNA-damaging agent idarubicin (IDA) overcame abiraterone and enzalutamide resistance in prostate cancer cells. IDA treatment inhibited the DNA repair protein XPA expression in a transcription-independent manner. Consistently, XPA knockout sensitized prostate cancer cells to abiraterone and enzalutamide treatment. In conclusion, IDA combats abiraterone and enzalutamide resistance by reducing XPA protein level in prostate cancer.

MicroRNAs in doxorubicin-induced cardiotoxicity: The DNA damage response

Doxorubicin (DOX) is a chemotherapeutic drug widely used for cancer treatment, but its use is limited by cardiotoxicity. Although free radicals from redox cycling and free cellular iron have been predominant as the suggested primary pathogenic mechanism, novel evidence has pointed to topoisomerase II inhibition and resultant genotoxic stress as the more fundamental mechanism. Recently, a growing list of microRNAs (miRNAs) has been implicated in DOX-induced cardiotoxicity (DIC). This review summarizes miRNAs reported in the recent literature in the context of DIC. A particular focus is given to miRNAs that regulate cellular responses downstream to DOX-induced DNA damage, especially p53 activation, pro-survival signaling pathway inhibition (e.g., AMPK, AKT, GATA-4, and sirtuin pathways), mitochondrial dysfunction, and ferroptosis. Since these pathways are potential targets for cardioprotection against DOX, an understanding of how miRNAs participate is necessary for developing future therapies.

The Role of Mitochondrial Quality Control in Anthracycline-Induced Cardiotoxicity: From Bench to Bedside

Cardiotoxicity is the major side effect of anthracyclines (doxorubicin, daunorubicin, epirubicin, and idarubicin), though being the most commonly used chemotherapy drugs and the mainstay of therapy in solid and hematological neoplasms. Advances in the field of cardio-oncology have expanded our understanding of the molecular mechanisms underlying anthracycline-induced cardiotoxicity (AIC). AIC has a complex pathogenesis that includes a variety of aspects such as oxidative stress, autophagy, and inflammation. Emerging evidence has strongly suggested that the loss of mitochondrial quality control (MQC) plays an important role in the progression of AIC. Mitochondria are vital organelles in the cardiomyocytes that serve as the key regulators of reactive oxygen species (ROS) production, energy metabolism, cell death, and calcium buffering. However, as mitochondria are susceptible to damage, the MQC system, including mitochondrial dynamics (fusion/fission), mitophagy, mitochondrial biogenesis, and mitochondrial protein quality control, appears to be crucial in maintaining mitochondrial homeostasis. In this review, we summarize current evidence on the role of MQC in the pathogenesis of AIC and highlight the therapeutic potential of restoring the cardiomyocyte MQC system in the prevention and intervention of AIC.

Anthracycline-induced cardiotoxicity: From pathobiology to identification of molecular targets for nuclear imaging

Anthracyclines are a widely used class of chemotherapy in pediatric and adult cancers, however, their use is hampered by the development of cardiotoxic side-effects and ensuing complications, primarily heart failure. Clinically used imaging modalities to screen for cardiotoxicity are mostly echocardiography and occasionally cardiac magnetic resonance imaging. However, the assessment of diastolic and global or segmental systolic function may not be sensitive to detect subclinical or early stages of cardiotoxicity. Multiple studies have scrutinized molecular nuclear imaging strategies to improve the detection of anthracycline-induced cardiotoxicity. Anthracyclines can activate all forms of cell death in cardiomyocytes. Injury mechanisms associated with anthracycline usage include apoptosis, necrosis, autophagy, ferroptosis, pyroptosis, reactive oxygen species, mitochondrial dysfunction, as well as cardiac fibrosis and perturbation in sympathetic drive and myocardial blood flow; some of which have been targeted using nuclear probes. This review retraces the pathobiology of anthracycline-induced cardiac injury, details the evidence to date supporting a molecular nuclear imaging strategy, explores disease mechanisms which have not yet been targeted, and proposes a clinical strategy incorporating molecular imaging to improve patient management.

Development and Validation of a Diagnostic Nomogram to Predict the Anthracycline-Induced Early Cardiotoxicity in Children with Hematological Tumors

This study aimed to establish and validate an effective nomogram to predict the risk of cardiotoxicity in children after each anthracycline treatment. According to the inclusion and exclusion criteria, the eligible children were randomly divided into the training cohort (75%) and the validation cohort (25%). Least absolute shrinkage and selection operator (LASSO) regression was used to select the predictors and a nomogram was developed. Then, concordance index (C-index), the area under the curve (AUC), Hosmer-Lemeshow (H-L) test, and decision curve analysis (DCA) were employed to evaluate the performance and clinical utility of nomogram. Internal validation was processed to inspect the stability of the model. A total of 796 eligible children were included in this study and divided into a training set (n = 597) and a validation set (n = 199). LASSO regression analysis revealed that cumulative anthracycline dose, ejection fractions, NT-proBNP, and diastolic dysfunction were effective predictors of cardiotoxicity. The nomogram was established based on these variables. The C-index and the AUC of the predicting nomogram were 0.818 in the training cohort and 0.773 in the validation cohort, suggesting that the nomogram had good discrimination. The calibration curve of the nomogram presented no significant deviation from the reference line, and the P-value of the H-L test was 0.283, implying a preferable degree of calibration. The threshold of DCA also reflects that the nomogram is clinically useful. A nomogram was developed to predict anthracycline chemotherapy-induced cardiotoxicity in children with hematological tumors. The nomogram has a good prediction effect and can provide a reference for clinicians' diagnosis and treatment.

The Beneficial Role of Physical Exercise on Anthracyclines Induced Cardiotoxicity in Breast Cancer Patients

The increase in breast cancer (BC) survival has determined a growing survivor population that seems to develop several comorbidities and, specifically, treatment-induced cardiovascular disease (CVD), especially those patients treated with anthracyclines. Indeed, it is known that these compounds act through the induction of supraphysiological production of reactive oxygen species (ROS), which appear to be central mediators of numerous direct and indirect cardiac adverse consequences. Evidence suggests that physical exercise (PE) practised before, during or after BC treatments could represent a viable non-pharmacological strategy as it increases heart tolerance against many cardiotoxic agents, and therefore improves several functional, subclinical, and clinical parameters. At molecular level, the cardioprotective effects are mainly associated with an exercise-induced increase of stress response proteins (HSP60 and HSP70) and antioxidant (SOD activity, GSH), as well as a decrease in lipid peroxidation, and pro-apoptotic proteins such as Bax, Bax-to-Bcl-2 ratio. Moreover, this protection can potentially be explained by a preservation of myosin heavy chain (MHC) isoform distribution. Despite this knowledge, it is not clear which type of exercise should be suggested in BC patient undergoing anthracycline treatment. This highlights the lack of special guidelines on how affected patients should be managed more efficiently. This review offers a general framework for the role of anthracyclines in the physio-pathological mechanisms of cardiotoxicity and the potential protective role of PE. Finally, potential exercise-based strategies are discussed on the basis of scientific findings.

Risk factors and early cardiovascular outcomes in cancer patients treated with anthracycline-based chemotherapy in Tanzania: a protocol for a quasi-experimental study

The objective of this quasi-experimental study is to assess the risk factors and early cardiovascular outcomes in cancer patients treated with anthracycline-based chemotherapy in Tanzania. The study will be conducted at Ocean Road Cancer Institute in Dar es salaam, Tanzania. The study will have three phases: baseline survey, follow-up, and end-line survey. Participants will be newly diagnosed adult cancer patients who are eligible for anthracycline-based chemotherapy. A total of 427 participants will be involved. At baseline, participants will be evaluated for the cardiovascular risk factors before commencing chemotherapy. During follow-up, participants will commence their prescribed anthracycline and the cardiovascular indices monitored throughout until the patient completes the prescribed anthracycline cycles. After completing the prescribed anthracycline cycles, an end line survey will be conducted to evaluate any change in cardiovascular indices. The outcome variable in this study will be the change in biochemical data (high-density lipoprotein, low-density lipoprotein, triglyceride, and troponin I), blood pressure, and electrocardiographic information (heart rate and Bazett QT interval). Independent variables will be demographic characteristics, risk factors for cardiovascular disorders, current dietary practices, and body mass index. Descriptive statistics will be used to describe the participants. Independent and paired t-tests will be performed to make comparisons between and within groups. P-values <0.05 will be considered statistically significant. The results of this study will help clinicians and policymakers to understand the burden of early cardiovascular outcomes and plan for appropriate preventive strategies.

Vitamin E and levocarnitine as prophylaxis against doxorubicin-induced cardio toxicity in the adult cancer patient: A review

OBJECTIVE

Doxorubicin, a component of the anthracycline group, is a highly effective in the treatment of hematologic and solid malignancies. Because of the cardiotoxic adverse effects, use is limited. Antioxidants may negate this anthracycline-induced cardiotoxicity, although the literature is not conclusive with regards to the cardioprotective benefits of antioxidants. This review assessed and mapped evidence of the efficacy of vitamin E and levocarnitine against doxorubicin-induced cardiotoxicity in adult cancer patients.

DATA SOURCES

This review was based on the Arksey and O'Malley methodology. Potentially relevant literature in English published between January 1960 and April 2021 was identified through a database search. Oxford Quality Scoring System and AMSTR2 were used to assess the quality of trials and systematic reviews respectively, as well as the risks of potential bias.

DATA SUMMARY

Nineteen of the 10 268 (0.2%) articles from the initial search were included in the final analysis (12 clinical trials and 7 systematic reviews). Vitamin E was included in seven prospective clinical trials. Levocarnitine was included in five clinical trials as an individual agent and a single trial as a combination treatment. No trials could be found investigating the combination of vitamin E and levocarnitine in humans.

CONCLUSIONS

This review found that levocarnitine trials showed some cardioprotective effects but the results from vitamin E trials were controversial and inconclusive. Most of the trials reviewed had some shortcomings. Further investigations are therefore needed to determine the efficacy of vitamin E and levocarnitine in preventing doxorubicin-induced cardiotoxicity in adult cancer patients.

Chemotherapy Side-Effects: Not All DNA Damage Is Equal

Recent advances have increased survival rates of children and adults suffering from cancer thanks to effective anti-cancer therapy, such as chemotherapy. However, during treatment and later in life they are frequently confronted with the severe negative side-effects of their life-saving treatment. The occurrence of numerous features of accelerated aging, seriously affecting quality of life, has now become one of the most pressing problems associated with (pediatric) cancer treatment. Chemotherapies frequently target and damage the DNA, causing mutations or genome instability, a major hallmark of both cancer and aging. However, there are numerous types of chemotherapeutic drugs that are genotoxic and interfere with DNA metabolism in different ways, each with their own biodistribution, kinetics, and biological fate. Depending on the type of DNA lesion produced (e.g., interference with DNA replication or RNA transcription), the organ or cell type inflicted (e.g., cell cycle or differentiation status, metabolic state, activity of clearance and detoxification mechanisms, the cellular condition or micro-environment), and the degree of exposure, outcomes of cancer treatment can largely differ. These considerations provide a conceptual framework in which different classes of chemotherapeutics contribute to the development of toxicities and accelerated aging of different organ systems. Here, we summarize frequently observed side-effects in (pediatric) ex-cancer patients and discuss which types of DNA damage might be responsible.

Cardiotoxicity in pediatric lymphoma survivors

INTRODUCTION

Over the past five decades, the diagnosis and management of children with various malignancies have improved tremendously. As a result, an increasing number of children are long-term cancer survivors. With improved survival, however, has come an increased risk of treatment-related cardiovascular complications that can appear decades later.

AREAS COVERED

This review discusses the pathophysiology, epidemiology and effects of treatment-related cardiovascular complications from anthracyclines and radiotherapy in pediatric lymphoma survivors. There is a paucity of evidence-based recommendations for screening for and treatment of cancer therapy-induced cardiovascular complications. We discuss current preventive measures and strategies for their treatment.

EXPERT OPINION

Significant cardiac adverse effects occur due to radiation and chemotherapy received by patients treated for lymphoma. Higher lifetime cumulative doses, female sex, longer follow-up, younger age, and preexisting cardiovascular disease are associated with a higher incidence of cardiotoxicity. With deeper understanding of the mechanisms of these adverse cardiac effects and identification of driver mutations causing these effects, personalized cancer therapy to limit cardiotoxic effects while ensuring an adequate anti-neoplastic effect would be ideal. In the meantime, expanding the use of cardioprotective agents with the best evidence such as dexrazoxane should be encouraged and further studied.

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.

Etiology and management of hypertension in patients with cancer

The pathophysiology of hypertension and cancer are intertwined. Hypertension has been associated with an increased likelihood of developing certain cancers and with higher cancer-related mortality. Moreover, various anticancer therapies have been reported to cause new elevated blood pressure or worsening of previously well-controlled hypertension. Hypertension is a well-established risk factor for the development of cardiovascular disease, which is rapidly emerging as one of the leading causes of death and disability in patients with cancer. In this review, we discuss the relationship between hypertension and cancer and the role that hypertension plays in exacerbating the risk for anthracycline- and trastuzumab-induced cardiomyopathy. We then review the common cancer therapies that have been associated with the development of hypertension, including VEGF inhibitors, small molecule tyrosine kinase inhibitors, proteasome inhibitors, alkylating agents, glucocorticoids, and immunosuppressive agents. When available, we present strategies for blood pressure management for each drug class. Finally, we discuss blood pressure goals for patients with cancer and strategies for assessment and management. It is of utmost importance to maintain optimal blood pressure control in the oncologic patient to reduce the risk of chemotherapy-induced cardiotoxicity and to decrease the risk of long-term cardiovascular disease.

Breast Radiotherapy-Related Cardiotoxicity. When, How, Why. Risk Prevention and Control Strategies

In recent decades, improvements in breast cancer management have increased overall patient survival; however, many cancer therapies have been linked to an important risk of cardiovascular adverse events. Cardio-oncology has been proposed as an emerging specialty to coordinate preventive strategies that improve the cardiovascular health of oncologic patients. It employs the most suitable personalized multidisciplinary management approach for each patient to optimize their cardiovascular health and improve their survival and quality of life. Radiotherapy is an essential part of the therapeutic regimen in breast cancer patients but can also increase the risk of cardiovascular disease. Therefore, minimizing the negative impact of radiation therapy is an important challenge for radiotherapy oncologists and cardiologists specializing in this field. The aim of the present review is to update our knowledge about radiation-induced cardiotoxicity in breast cancer patients by undertaking a critical review of the relevant literature to determine risk prevention and control strategies currently available.

Protection against chemotherapy- and radiotherapy-induced side effects: A review based on the mechanisms and therapeutic opportunities of phytochemicals

BACKGROUND

Although great achievements have been made in the field of cancer therapy, chemotherapy and radiotherapy remain the mainstay cancer therapeutic modalities. However, they are associated with various side effects, including cardiocytotoxicity, nephrotoxicity, myelosuppression, neurotoxicity, hepatotoxicity, gastrointestinal toxicity, mucositis, and alopecia, which severely affect the quality of life of cancer patients. Plants harbor a great chemical diversity and flexible biological properties that are well-compatible with their use as adjuvant therapy in reducing the side effects of cancer therapy.

PURPOSE

This review aimed to comprehensively summarize the molecular mechanisms by which phytochemicals ameliorate the side effects of cancer therapies and their potential clinical applications.

METHODS

We obtained information from PubMed, Science Direct, Web of Science, and Google scholar, and introduced the molecular mechanisms by which chemotherapeutic drugs and irradiation induce toxic side effects. Accordingly, we summarized the underlying mechanisms of representative phytochemicals in reducing these side effects.

RESULTS

Representative phytochemicals exhibit a great potential in reducing the side effects of chemotherapy and radiotherapy due to their broad range of biological activities, including antioxidation, antimutagenesis, anti-inflammation, myeloprotection, and immunomodulation. However, since a majority of the phytochemicals have only been subjected to preclinical studies, clinical trials are imperative to comprehensively evaluate their therapeutic values.

CONCLUSION

This review highlights that phytochemicals have interesting properties in relieving the side effects of chemotherapy and radiotherapy. Future studies are required to explore the clinical benefits of these phytochemicals for exploitation in chemotherapy and radiotherapy.

The role of iron in doxorubicin-induced cardiotoxicity: recent advances and implication for drug delivery

As an anthracycline antibiotic, doxorubicin (DOX) is one of the most potent and widely used chemotherapeutic agents for treating various types of tumors. Unfortunately, the clinical application of this drug results in severe side effects, particularly dose-dependent cardiotoxicity. There are multiple mechanisms involved with the cardiotoxicity caused by DOX, among which intracellular iron homeostasis plays an essential role based on a recent discovery. In this mini-review, we summarize the clinical features and symptoms of DOX-dependent cardiotoxicity, discuss the correlation between iron and cardiotoxicity, and highlight the involvement of iron-dependent ferroptotic cell death therein. Recent advances in this topic will aid the development of novel DOX delivery systems with reduced adverse effects, and expand the clinical application of anthracycline.

Red Blood Cell Distribution Width Is a Predictive Factor of Anthracycline-Induced Cardiotoxicity

Background: Red blood cell distribution width (RDW) is associated with prognosis in widespread cardiovascular fields, but little is known about relationship with the onset of cancer therapeutics-related cardiac dysfunction (CTRCD).

Objectives: The purpose of this study was to assess whether RDW could predict the onset of CTRCD by anthracycline.

Methods: Consequential 202 cancer patients planed for anthracycline treatment were enrolled and followed up for 12 months. The patients were divided into 2 groups based on the median value of baseline RDW before chemotherapy [low RDW group, n = 98, 13.0 [12.6–13.2]; high RDW group, n = 104, 14.9 [13.9–17.0]]. Cardiac function was assessed serially by echocardiography at baseline (before chemotherapy), as well as at 3, 6, and 12 months after chemotherapy with anthracycline.

Results: Baseline left ventricular end systolic volume index and ejection fraction (EF) were similar between two groups. After chemotherapy, EF decreased at 3- and 6-month in the high RDW group [baseline, 64.5% [61.9–68.9%]; 3-month, 62.6% [60.4–66.9%]; 6-month, 63.9% [60.0–67.9%]; 12-month, 64.7% [60.8–67.0%], P = 0.04], but no change was observed in low RDW group. The occurrence of CTRCD was higher in high RDW group than in low RDW group (11.5 vs. 2.0%, P = 0.008). When we set the cut-off value of RDW at 13.8, sensitivity and specificity to predict CTRCD were 84.6 and 62.0%, respectively. Multivariable logistic regression analysis revealed that baseline RDW value was an independent predictor of the development of CTRCD [odds ratio 1.390, 95% CI [1.09–1.78], P = 0.008]. The value of net reclassification index (NRI) and integrated discrimination improvement (IDI) for detecting CTRCD reached statistical significance when baseline RDW value was added to the regression model including known risk factors such as cumulative anthracycline dose, EF, albumin, and the presence of hypertension; 0.9252 (95%CI 0.4103–1.4402, P < 0.001) for NRI and 0.1125 (95%CI 0.0078–0.2171, P = 0.035) for IDI.

Conclusions: Baseline RDW is a novel parameter to predict anthracycline-induced CTRCD.

Pathophysiological mechanisms of cardiotoxicity in chemotherapeutic agents

Certain success has been achieved in the treatment of cancer due to the development of various effective chemotherapeutic drugs. However, an increase in their effectiveness (aggressiveness) was associated with a growth of undesirable effects on the entire human body, in particular, on the cardiovascular system. The damage to the cardiovascular system from chemotherapy in many cases is more significant than from the underlying disease. In recent years, a new direction of medicine has been formed - cardio-oncology. The major groups of cardiotoxic chemotherapeutic agents are anthracyclines, inhibitors of epidermal growth factor receptor type 2 (anti-HER2), antimetabolites, microtubule inhibitors, proteasome inhibitors, platinum-based chemotherapeutic drugs, and angiogenesis inhibitors (inhibitors of vascular endothelial growth factor). This review discusses principal pathophysiological mechanisms of the cardiotoxicity of these chemotherapeutic drugs.

Heart slice culture system reliably demonstrates clinical drug-related cardiotoxicity

The limited availability of human heart tissue and its complex cell composition are major limiting factors for the reliable testing of drug efficacy and toxicity. Recently, we developed functional human and pig heart slice biomimetic culture systems that preserve the viability and functionality of 300 μm heart slices for up to 6 days. Here, we tested the reliability of this culture system for testing the cardiotoxicity of anti-cancer drugs. We tested three anti-cancer drugs (doxorubicin, trastuzumab, and sunitinib) with known different mechanisms of cardiotoxicity at three concentrations and assessed the effect of these drugs on heart slice viability, structure, function and gene expression. Slices incubated with any of these drugs for 48 h showed diminished in viability as well as loss of cardiomyocyte structure and function. Mechanistically, RNA sequencing of doxorubicin-treated tissues demonstrated a significant downregulation of cardiac genes and upregulation of oxidative stress responses. Trastuzumab treatment downregulated cardiac muscle contraction-related genes consistent with its clinically known effect on cardiomyocytes. Interestingly, sunitinib treatment resulted in significant downregulation of angiogenesis-related genes, in line with its mechanism of action. Similar to hiPS-derived-cardiomyocytes, heart slices recapitulated the expected toxicity of doxorubicin and trastuzumab, however, slices were superior in detecting sunitinib cardiotoxicity and mechanism in the clinically relevant concentration range of 0.1-1 μM. These results indicate that heart slice culture models have the potential to become a reliable platform for testing and elucidating mechanisms of drug cardiotoxicity.

The beneficial effects of reducing NLRP3 inflammasome activation in the cardiotoxicity and the anti-cancer effects of doxorubicin

Doxorubicin (DOX) is a powerful broad-spectrum anti-neoplastic anthracycline antibiotic. However, DOX may cause a dose-dependent cardiotoxicity that can eventually progress to congestive heart failure and death. Numerous molecular mechanisms have been implicated in the cardiotoxic effect of DOX including topoisomerase IIβ and generation of free radicals. However, targeting these pathways appears to be insufficient to mitigate the cardiotoxic effects of DOX and/or ultimately reduces the anti-tumor activity of DOX. Thus, there remains a crucial need to identify novel pharmacological targets that can alleviate the cardiotoxic effects of DOX without reducing its anti-tumor activity. Recent studies have suggested that the Nucleotide-Binding Domain-Like Receptor Protein 3 (NLRP3) inflammasome is implicated in tumor progression and the chemoresistance of cancer cells to DOX. Of interest, reducing NLRP3 inflammasome activity alleviates DOX-induced cardiotoxicity. Therefore, we postulate that strategies that target the NLRP3 inflammasome can help mitigate the cardiotoxic effects of DOX while maintaining and/or even enhancing its anti-cancer activity. Herein, we review the current knowledge about the potential implication of the NLRP3 inflammasome in the anti-cancer and cardiotoxic effects of DOX.

Cardiac Troponin I Predicts Elevated B-type Natriuretic Peptide in Patients Treated with Anthracycline-Containing Chemotherapy

BACKGROUND

Anthracycline is used to treat various types of cancer; however, cardiotoxicity negatively affects patient prognosis.

OBJECTIVES

The aim of the present study was to investigate serial changes in levels of cardiac troponin I (TnI) and B-type natriuretic peptide (BNP) in patients treated with anthracycline-containing therapy.

METHODS

91 consecutive cancer patients planned for anthracycline treatment were enrolled and followed up for 12 months. All patients underwent echocardiography and blood sampling at baseline, 3, 6, and 12 months.

RESULTS

The patients were divided into two groups based on their TnI level during the follow-up period: the elevated TnI group (TnI ≥0.03 ng/mL; n = 37) and the normal TnI group (n = 54). In the elevated TnI group, the TnI levels increased at 3 and 6 months, but they returned to within normal range at 12 months after anthracycline administration. Unlike TnI, the BNP levels began to increase after 6 months, and remained increased at 12 months. The occurrence of cancer therapeutics-related cardiac dysfunction was higher in the elevated TnI group than in the normal TnI group. When we set the cut-off value of TnI at 0.029 ng/mL, sensitivity and specificity to predict an elevated BNP level of more than 100 pg/mL were 90 and 63%, respectively. Multivariate logistic regression analysis revealed that elevated TnI was an independent predictor of elevated BNP levels.

CONCLUSION

Elevated TnI was an independent predictor for the development of BNP increase. The different characteristics of TnI and BNP should be considered when managing patients treated with anthracycline-containing therapy.

Cardiac monitoring in HER2-positive patients on trastuzumab treatment: A review and implications for clinical practice

Trastuzumab prolongs progression-free and overall survival in patients with human epidermal growth factor receptor 2 (HER2) positive breast cancer. However, trastuzumab treatment is hampered by cardiotoxicity, defined as a left ventricular ejection fraction (LVEF) decline with a reported incidence ranging from 3 to 27% depending on variable factors. Early identification of patients at increased risk of trastuzumab-induced myocardial damage is of great importance to prevent deterioration to irreversible cardiotoxicity. Although current cardiac monitoring with multi gated acquisition (MUGA) scanning and/or conventional 2D-echocardiography (2DE) have a high availability, their reproducibility are modest, and more sensitive and reliable techniques are needed such as 3D-echocardiography (3DE) and speckle tracking echocardiography (STE). But which other diagnostic imaging modalities are available for patients before and during trastuzumab treatment? In addition, what is the optimal frequency and duration of cardiac monitoring? At last, which biomarker monitoring strategies are currently available for the identification of cardiotoxicity in patients treated with trastuzumab?

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Current MUGA is not sensitive and reliable enough to detect cardiotoxicity early.

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3DE (with STE) is most suitable for cardiac monitoring of patients on trastuzumab.

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The optimal frequency and duration of cardiac monitoring is not yet established.

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MPO and hs-troponin are promising biomarkers to detect cardiotoxicity.

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.

Incidence and Associated Risk Factors of Chemotherapy-Induced Cardiomyopathy in the African American and Afro-Caribbean Populations

BACKGROUND

Chemotherapy-induced cardiomyopathy (CICM) and heart failure are major complications of cancer therapeutics and can result in significant morbidity and mortality. There is limited data on the incidence and risk factors of CICM in African American and Afro-Caribbean patients.

METHODS

We performed a retrospective chart review to evaluate the baseline characteristics that may predispose to CICM. Patients were African American and Afro-Caribbean ethnicity. Data was collected between 2014 to 2018. Patients had transthoracic echocardiogram (TTE) or multigated acquisition scan (MUGA) prior to cancer therapy and every 3 months thereafter, until the end of the regimen. CICM was defined as a ≥16% reduction in LVEF or ≥10% reduction in LVEF to a value <50%.

RESULTS

A total of 230 patients were studied, with a mean age of 54±12 years with 91% were females, BMI 30±4, 81% were taking anthracyclines, 87% were on Trastuzumab while 5% were receiving both medications. The prevalence of comorbidities was as follows: hypertension 8%, diabetes mellitus 8%, ESRD 8%, dyslipidemia 8%, CAD 7%. The incidence of CICM was 7% overall, while it was 6% and 8% for patients taking Anthracyclines and Trastuzumab, respectively. CICM was associated with dyslipidemia (r= .22, p= .001), hypertension (r= .12, p= .05), baseline ejection fraction (r= -.21, p= .001) and concomitant use of radiation therapy (r= .147, p= .02), but not with age, gender, beta blocker use, angiotensin converting enzyme inhibitor use, number of chemotherapy cycles or stage of the malignancy. On multivariate analysis CICM was independently associated with baseline ejection fraction (β= -.193, P= .003) and dyslipidemia (β= -.20, P= .003).

CONCLUSION

The incidence of CICM in African Americans and Afro-Caribbean is higher than reported in the general population. Dyslipidemia and baseline ejection fraction were seen as the major risk factors associated with the higher incidence of CICM.

Thyroxine Alleviates Energy Failure, Prevents Myocardial Cell Apoptosis, and Protects against Doxorubicin-Induced Cardiac Injury and Cardiac Dysfunction via the LKB1/AMPK/mTOR Axis in Mice

Background

Previous studies have demonstrated that energy failure is closely associated with cardiac injury. Doxorubicin (DOX) is a commonly used clinical chemotherapy drug that can mediate cardiac injury through a variety of mechanisms. Thyroxine is well known to play a critical role in energy generation; thus, this study is aimed at investigating whether thyroxine can attenuate DOX-induced cardiac injury by regulating energy generation.

Methods

First, the effect of DOX on adenosine diphosphate (ADP) and adenosine triphosphate (ATP) ratios in mice was assessed. In addition, thyroxine was given to mice before they were treated with DOX to investigate the effects of thyroxine on DOX-induced cardiac injury. Furthermore, to determine whether the liver kinase b1 (LKB1)/adenosine 5′-monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) axis mediated the effect of thyroxine on DOX-induced cardiac injury, thyroxine was given to DOX-treated LKB1 knockout (KO) mice.

Results

DOX treatment time- and dose-dependently increased the ADP/ATP ratio. Thyroxine treatment also reduced lactate dehydrogenase (LDH) and creatine kinase myocardial band (CK-MB) levels in both serum and heart tissue and alleviated cardiac dysfunction in DOX-treated mice. Furthermore, thyroxine reversed DOX-induced reductions in LKB1 and AMPK phosphorylation; mitochondrial complex I, III, and IV activity; and mitochondrial swelling and reversed DOX-induced increases in mTOR pathway phosphorylation and myocardial cell apoptosis. These effects of thyroxine on DOX-treated mice were significantly attenuated by LKB1 KO.

Conclusions

Thyroxine alleviates energy failure, reduces myocardial cell apoptosis, and protects against DOX-induced cardiac injury via the LKB1/AMPK/mTOR axis in mice. Thyroxine may be a new agent for the clinical prevention of cardiac injury in tumor patients undergoing chemotherapy with DOX.

Strategies to prevent anthracycline-induced cardiotoxicity in cancer survivors

Cancer diagnostics and therapies have improved steadily over the last few decades, markedly increasing life expectancy for patients at all ages. However, conventional and newer anti-neoplastic therapies can cause short- and long-term cardiotoxicity. The clinical implications of this cardiotoxicity become more important with the increasing use of cardiotoxic drugs. The implications are especially serious among patients predisposed to adverse cardiac effects, such as youth, the elderly, those with cardiovascular comorbidities, and those receiving additional chemotherapies or thoracic radiation. However, the optimal strategy for preventing and managing chemotherapy-induced cardiotoxicity remains unknown. The routine use of neurohormonal antagonists for cardioprotection is not currently justified, given the marginal benefits and associated adverse events, particularly with long-term use. The only United States Food and Drug Administration and European Medicines Agency approved treatment for preventing anthracycline-related cardiomyopathy is dexrazoxane. We advocate administering dexrazoxane during cancer treatment to limit the cardiotoxic effects of anthracycline chemotherapy.

A review on the cardioprotective mechanisms of metformin against doxorubicin

Doxorubicin (DOX) is an antineoplastic agent obtained from Streptomyces peucetius. It is utilized in treating different kinds of cancers, such as leukemia, lymphoma, and lung, and breast cancers. The main side effect of DOX is cardiotoxicity. Metformin (MET) is an antihyperglycemic drug used for type 2 diabetes treatment. It is proposed that MET has a protective effect against DOX cardiotoxicity. Our review demonstrated that MET has several possible mechanisms of action, which can prevent or at least reduce DOX cardiotoxicity including a decrease of free radical generation and oxidative stress, 5′ adenosine monophosphate-activated protein kinase activation, and ferritin heavy chain expression in cardiomyocytes cells. The combination of MET and DOX has been shown to enhance the anticancer activity of DOX by a number of authors. The literature reviewed in the present report supports the hypothesis that MET can reduce the cardiotoxicity that often occurs with DOX treatment.

Management of cardiovascular risk in patients with multiple myeloma

Multiple myeloma (MM) is a plasma cell malignancy that accounts for 10% of hematological cancers. It predominantly affects elderly people; median age at diagnosis is 70 years. Consequently, many patients with MM have cardiovascular comorbidities or risk factors. MM can cause cardiac comorbidities such as cardiomyopathy and heart failure caused by cardiac amyloidosis and/or anemia. Some of the treatments used in MM can also affect cardiovascular health. Advances in pharmacotherapy for MM, such as the introduction of immunomodulators, proteasome inhibitors, histone deacetylase inhibitors, and monoclonal antibodies, have dramatically improved progression-free survival and life expectancy, but new agent classes are associated with adverse events that were not previously observed on a regular basis, including cardiovascular events. However, with careful risk assessment, monitoring, and prophylactic therapy, many of these cardiovascular complications can be managed or treated successfully. Most routine cardiovascular surveillance is undertaken by the treating hemato-oncologist, but a multidisciplinary approach involving cardiologists may help to optimize patient outcomes. In this review, we survey the cardiac complications commonly reported in patients with MM, discuss how they can be prevented and managed, and summarize the role cardiologists can play in delivering the best possible outcomes for patients with MM and cardiovascular comorbidities.

Pediatric Anthracycline-Induced Cardiotoxicity: Mechanisms, Pharmacogenomics, and Pluripotent Stem-Cell Modeling

Anthracycline‐induced cardiotoxicity (ACT) is a severe adverse drug reaction for a subset of children treated with anthracyclines as part of chemotherapy protocols. The identification of genetic markers associated with increased ACT susceptibility has clinical significance toward improving patient care and our understanding of the molecular mechanisms involved in ACT. Human‐induced pluripotent stem cell–derived cardiomyocytes represent a novel approach to determine the pharmacogenomics of ACT and guide the development of genetic screening tests.

Interleukin-12p35 Knock Out Aggravates Doxorubicin-Induced Cardiac Injury and Dysfunction by Aggravating the Inflammatory Response, Oxidative Stress, Apoptosis and Autophagy in Mice

Background

Recent evidence has demonstrated that interleukin 12p35 knockout (IL-12p35 KO) is involved in cardiac diseases by regulating the inflammatory response. The involvement of inflammatory cells has also been observed in doxorubicin (DOX)-induced cardiac injury. This study aimed to investigate whether IL-12p35 KO affects DOX-induced cardiac injury and the underlying mechanisms.

Methods

First, the effect of DOX treatment on cardiac IL-12p35 expression was assessed. In addition, to investigate the effect of IL-12p35 KO on DOX-induced cardiac injury, IL-12p35 KO mice were treated with DOX. Because IL-12p35 is the mutual subunit of IL-12 and IL-35, to determine the cytokine that mediates the effect of IL-12p35 KO on DOX-induced cardiac injury, mice were given phosphate-buffered saline (PBS), mouse recombinant IL-12 (rIL-12) or rIL-35 before treatment with DOX.

Results

DOX treatment significantly increased the level of cardiac IL-12p35 expression. In addition, IL-12p35 KO mice exhibited higher serum and heart lactate dehydrogenase levels, higher serum and heart creatine kinase myocardial bound levels, and greater cardiac dysfunction than DOX-treated mice. Furthermore, IL-12p35 KO further increased M1 macrophage and decreased M2 macrophage differentiation, aggravated the imbalance of oxidants and antioxidants, and further activated the mitochondrial apoptotic pathway and endoplasmic reticulum stress autophagy pathway. Both rIL-12 and rIL-35 protected against DOX-induced cardiac injury by alleviating the inflammatory response, oxidative stress, apoptosis and autophagy.

Conclusions

IL-12p35 KO aggravated DOX-induced cardiac injury by amplifying the levels of inflammation, oxidative stress, apoptosis and autophagy. (234 words).

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IL-12p35 KO aggravates DOX-induced cardiac injury and dysfunction.

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IL-12p35 further increases the DOX-induced imbalance in inflammation, oxidative stress, apoptosis and autophagy.

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Both exogenous rIL-12 and rIL-35 relieved cardiac injury mediated by DOX.

CD4+ T helper (Th) cells are closely related to cardiac injury; regulatory T cells (Tregs) are a new subset of Th cells, and IL-35 is the functional cytokine of Tregs. Cardiac injury mediated by DOX is the most serious complication during chemotherapy, and there are no good preventive measures. This study aimed to investigate whether IL-35 can reduce cardiac injury induced by DOX during chemotherapy. In addition to IL-35, IL-12p35 KO can cancel the biological effect of IL-12; therefore, we also determined whether IL-12 participates in DOX-induced cardiac injury and the underlying mechanisms.

Up-regulation of NOX1/NADPH oxidase following drug-induced myocardial injury promotes cardiac dysfunction and fibrosis

Cardiac fibrosis is a common feature in failing heart and therapeutic strategy to halt the progression of fibrosis is highly needed. We here report on NOX1, a non-phagocytic isoform of superoxide-producing NADPH oxidase, which promotes cardiac fibrosis in a drug-induced myocardial injury model. A single-dose administration of doxorubicin (DOX) elicited cardiac dysfunction accompanied by increased production of reactive oxygen species and marked elevation of NOX1 mRNA in the heart. In mice deficient in Nox1 (Nox1^-/Y), cardiac functions were well retained and overall survival was significantly improved. However, increased level of serum creatine kinase was equivalent to that of wild-type mice (Nox1^+/Y). At 4 days after DOX treatment, severe cardiac fibrosis accompanied by increased hydroxyproline content and activation of matrix metalloproteinase-9 was demonstrated in Nox1^+/Y, but it was significantly attenuated in Nox1^-/Y. When H9c2 cardiomyocytes were exposed to their homogenate, a dose-dependent increase in NOX1 mRNA was observed. Up-regulation of NOX1 mRNA in H9c2 co-incubated with their homogenate was abolished in the presence of TAK242, a TLR4 inhibitor. When isolated cardiac fibroblasts were exposed to H9c2 homogenates, increased proliferation and up-regulation of collagen 3a1 mRNA were demonstrated. These changes were significantly attenuated in cardiac fibroblasts exposed to homogenates from H9c2 harboring disrupted Nox1. These findings suggest that up-regulation of NOX1 following cellular damage promotes cardiac dysfunction and fibrosis by aggravating the pro-fibrotic response of cardiac fibroblasts. Modulation of the NOX1/NADPH oxidase signaling pathway may be a novel therapeutic strategy for preventing heart failure after myocardial injury.

A Review on the Effect of Traditional Chinese Medicine Against Anthracycline-Induced Cardiac Toxicity

Anthracyclines are effective agents generally used to treat solid-tumor and hematologic malignancies. The use of anthracyclines for over 40 years has improved cancer survival statistics. Nevertheless, the clinical utility of anthracyclines is limited by its dose-dependent cardiotoxicity that adversely affects 10-30% of patients. Anthracycline-induced cardiotoxicity may be classified as acute/subacute or chronic/late toxicity and leads to devastating adverse effects resulting in poor quality of life, morbidity, and premature mortality. Traditional Chinese medicine has a history of over 2,000 years, involving both unique theories and substantial experience. Several studies have investigated the potential of natural products to decrease the cardiotoxic effects of chemotherapeutic agents on healthy cells, without negatively affecting their antineoplastic activity. This article discusses the mechanism of anthracycline-induced cardiotoxicity, and summarizes traditional Chinese medicine treatment for anthracycline-induced heart failure (HF), cardiac arrhythmia, cardiomyopathy, and myocardial ischemia in recent years, in order to provide a reference for the clinical prevention and treatment of cardiac toxicity.

Nanoceria ameliorates doxorubicin induced cardiotoxicity: Possible mitigation via reduction of oxidative stress and inflammation

Doxorubicin (DOX) is one of the most commonly used anticancer drugs but its use has been limited due to constraints of cardiotoxic side effects. The precise mechanism underlying cardiotoxicity is not yet fully understood but oxidative stress has been found to be a primary mechanism behind this. In addition, DOX induced cardiotoxicity also shows involvement of proinflammatory cytokines such as IL-6 and TNF-α. Since oxidative stress plays major role in DOX induced cardiotoxicity, different antioxidants have been tried to prevent cardiotoxicity of DOX. Nanoparticles have risen up as a promising material with a wide variety of actions, and cerium oxide nanoparticles or nanoceria (NC) is one of such kind with great antioxidant potential. NC has emerged as a promising antioxidant in different pathological conditions. The present study was aimed to investigate possible protective effects of NC in DOX induced cardiotoxicity. Cardiotoxicity was induced in Swiss mice by DOX administration through i.p. route at a dose level of 15 mg/kg in two divided doses on alternate days. In our study, NC was found to mitigate cardiotoxic potential of DOX and prevented weight loss. NC restored the levels of cardiac injury markers lactate dehydrogenase (LDH) and creatinine kinase MB (CK-MB). Moreover, NC reduced malondialdehyde (MDA) levels and increased endogenous antioxidants such as reduced glutathione (GSH) and catalase levels. In addition, NC decreased proinflammatory cytokine levels and also prevented the alteration in normal structure of heart samples. Our study showed protective effects of NC in DOX induced cardiotoxicity which can become a potential therapeutic intervention against DOX induced cardiotoxicity.

Prevention of doxorubicin (DOX)-induced genotoxicity and cardiotoxicity: Effect of plant derived small molecule indole-3-carbinol (I3C) on oxidative stress and inflammation

Doxorubicin (DOX) is an anthracycline group of antibiotic available for the treatment of broad spectrum of human cancers. However, patient receiving DOX-therapy, myelosuppression and genotoxicity which may lead to secondary malignancy and dose dependent cardiotoxicity is an imperative adverse effect. Mechanisms behind the DOX-induced toxicities are increased level of oxidative damage, inflammation and apoptosis. Therefore, in search of a potential chemoprotectant, naturally occurring glucosinolate breakdown product Indole-3-Carbinol (I3C) was evaluated against DOX-induced toxicities in Swiss albino mice. DOX was administered (5 mg/kg b.w., i.p.) and I3C was administered (20 mg/kg b.w., p.o.) in concomitant and 15 days pretreatment schedule. Results of the present study showed that I3C appreciably mitigated DOX-induced chromosomal aberrations, micronuclei formation, DNA damage and apoptosis in bone marrow niche. Histopathological observations revealed that DOX-intoxication resulted in massive structural and functional impairment of heart and bone marrow niche. However, oral administration of I3C significantly attenuated DOX-induced oxidative stress in the cardiac tissues as evident from decreased levels of ROS/RNS and lipid peroxidation, and by increased level of glutathione (reduced) and the activity of phase-II antioxidant enzymes. Additionally, administration of I3C significantly (P < 0.05) stimulated Nrf2-mediated activation of antioxidant response element (ARE) pathway and promoted expression of cytoprotective proteins heme oxygenase 1 (HO-1), NAD(P)H:quinine oxidoreductase 1 (NQO1) and GSTπ in bone marrow and cardiac tissues. In connection with that, I3C significantly attenuated DOX-induced inflammation by downregulation of pro-inflammatory mediators, viz., NF-kβ(p50), iNOS, COX-2 and IL-6 expression. Moreover, I3C attenuate DOX-induced apoptosis by up-regulation of Bcl2 and down-regulation of Bax and caspase-3 expression in bone marrow cells. Thus, this study suggests that I3C has promising chemoprotective efficacy against DOX-induced toxicities and indicates its future use as an adjuvant in chemotherapy.

Protective effect of paracetamol in doxorubicin-induced cardiotoxicity in ischemia/reperfused isolated rat heart

OBJECTIVE

Doxorubicin (DOX) induces cardiac dysfunction. Paracetamol (APAP) has also been established as an effective cardioprotective agent during ischemia/reperfusion. Therefore, this study aims to evaluate the effect of APAP on DOX-induced cardiotoxicity in ischemia/reperfused isolated rat heart.

METHODS

A total of 36 rats were equally divided into four groups: control, DOX (30 min, 20 µM DOX perfusion), APAP (15 min before and after ischemia, 0.35 mM APAP perfusion), and DOX+APAP (perfused with the same protocol in DOX and APAP groups). The isolated hearts were perfused according to the Langendorff method. Cardiac parameters, including left ventricular developed pressure (LVDP), heart rate (HR), coronary flow (CF), and rate pressure product (RPP; LVDP×HR) were measured. Lactate dehydrogenase (LDH) concentration was also assessed.

RESULTS

At the end of the baseline period, the RPP, HR, and CF values were lower in the DOX group than in the control group (p<0.01). Meanwhile, there were no significant differences between the values of cardiac function parameters in the DOX+APAP and control groups. In the reperfusion period, the RPP and CF values were significantly increased in the DOX+APAP group compared with the DOX group (p<0.05). Furthermore, the LDH concentration was decreased in the DOX+APAP group compared with the DOX group.

CONCLUSION

APAP perfusion protected the hearts against DOX-induced cardiotoxicity in the baseline and ischemia/reperfusion conditions. These findings can be explained by the effect of APAP on antioxidant capacity and mitochondrial permeability transition pores.

Out of the frying pan and into the fire: damage-associated molecular patterns and cardiovascular toxicity following cancer therapy

Cardio-oncology is a new and rapidly expanding field that merges cancer and cardiovascular disease. Cardiovascular disease is an omnipresent side effect of cancer therapy; in fact, it is the second leading cause of death in cancer survivors after recurrent cancer. It has been well documented that many cancer chemotherapeutic agents cause cardiovascular toxicity. Nonetheless, the underlying cause of cancer therapy-induced cardiovascular toxicity is largely unknown. In this review, we discuss the potential role of damage-associated molecular patterns (DAMPs) as an underlying contributor to cancer therapy-induced cardiovascular toxicity. With an increasing number of cancer patients, as well as extended life expectancy, understanding the mechanisms underlying cancer therapy-induced cardiovascular disease is of the utmost importance to ensure that cancer is the only disease burden that cancer survivors have to endure.

Effects of treatment with chemotherapy and/or tamoxifen on the biomarkers of cardiac injury and oxidative stress in women with breast cancer

There has been an increase in deaths from cardiovascular diseases following breast cancer therapy. Evidence has shown that this outcome is, in part, associated with cardiotoxicity induced by the chemotherapeutic drugs and the increase in oxidative stress. The aim of this study was to evaluate the effects of chemotherapy and hormone therapy with tamoxifen on the biomarkers of cardiac injury and oxidative stress in women with breast cancer.Thirty women were followed-up for 1 year and were divided into 3 groups according to the treatment protocol: women treated only with tamoxifen and clinical follow up for 12 months (Tam, n = 10); women treated only with chemotherapy for 6 months with clinical follow up for an additional 6-month period (Chemo, n = 10); and women who received chemotherapy for 6 months followed by a 6-month period only with tamoxifen therapy and clinical follow up (Chemo + Tam, n = 10). Analysis of the blood levels of cardiac troponin I (cTnI), advanced oxidation protein products (AOPP) and the activity of the plasmatic isoform of the antioxidant enzyme glutathione peroxidase (GPx) was performed before treatment (T0) and at 6 (T6) and 12 (T12) months after treatment.The Chemo group showed higher levels of cTnI (0.065 ± 0.006 ng/mL, P < .05) and AOPP (4.99 ± 0.84 μmol/L, P < .05) and reduced GPx activity (24.4 ± 1.1 nM/min/mL, P < .05) at T12 than the Tam group (cTnI: 0.031 ± 0.001 ng/mL; AOPP: 1.40 ± 0.10 μmol/L; GPx: 28.0 ± 0.7 nM/min/mL) and Chemo + Tam group (cTnI: 0.037 ± 0.002 ng/mL; AOPP: 2.53 ± 0.30 μmol/L; GPx: 29.5 ± 1.0 nM/min/mL).These data support the hypothesis that long-term oxidative stress after chemotherapy may have an impact on cardiovascular diseases and that tamoxifen has cardioprotective effects.

Cardiotoxic Effects of Short-Term Doxorubicin Administration: Involvement of Connexin 43 in Calcium Impairment

The use of Doxorubicin (DOXO), a potent antineoplastic agent, is limited by the development of cardiotoxicity. DOXO-induced cardiotoxicity is multifactorial, although alterations in calcium homeostasis, seem to be involved. Since even the Connexin43 (Cx43) plays a pivotal role in these two phenomena, in this study we have analyzed the effects of DOXO on Cx43 expression and localization. Damage caused by anthracyclines on cardiomyocytes is immediate after each injection, in the present study we used a short-term model of DOXO-induced cardiomyopathy. C57BL/6j female mice were randomly divided in groups and injected with DOXO (2 or 10 mg/kg i.p.) for 1–3 or 7 days once every other day. Cardiac function was assessed by Echocardiography. Sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCAII) and phospholamban (PLB) expression were assessed by Western blot analysis, intracellular [Ca²⁺] were detected spectrofluorometrically by means of Fura-2 pentakis (acetoxymethyl) ester (FURA-2AM), and Cx43 and pCx43 expression and localization was analyzed by Western blot and confirmed by immunofluorescence analysis. DOXO induces impairment in Ca²⁺ homeostasis, already evident after a single administration, and affects Cx43 expression and localization. Our data suggest that DOXO-induced alterations in Ca²⁺ homeostasis causes in the cells the induction of compensatory mechanisms until a certain threshold, above which cardiac injury is triggered.