Impact of hemochromatosis gene mutations on cardiac status in doxorubicin-treated survivors of childhood high-risk leukemia

Influence of genetic biomarkers on cardiac diseases in childhood cancer survivors: a systematic review

Childhood cancer survivors (CCS) often suffer from cardiac disease (CD) after treatment that included anthracycline and radiotherapy involving the heart. However, the variability in CD occurrence cannot be explained solely by these treatments, suggesting the existence of genetic predisposition. We conducted a systematic review searching on Medline-PubMed and Scopus, to identify studies reporting associations between genetic factors and CD in CCS. We included studies published up to 11 April 2023, with no lower limit, and assessed the quality of genetic associations by the Q-genie tool. As a result, 20 studies were included (15 case-control and five cohorts), revealing several genes and variants associated with cardiomyopathy, among which, SLC28A3-rs7853758, RARG-rs2229774, P2RX7-rs208294 and P2RX7-rs3751143 variants gave the most consistent findings. This review highlights the necessity to establish a set of clinically useful genes and variants to identify patients most at risk of developing cardiomyopathy, and to implement monitoring and prevention strategies.

Drugs Metabolism-Related Genes Variants Impact on Anthracycline-Based Chemotherapy Induced Subclinical Cardiotoxicity in Breast Cancer Patients

Breast cancer is the most common cancer in women worldwide. Anthracyclines (doxorubicin, epirubicin, daunorubicin, idarubicin) are among the most used drugs for the treatment of breast cancer. Unfortunately, anthracyclines cause cardiotoxicity, which is a limiting factor for its use, and the lifetime cumulative dose of anthracyclines is the major risk factor for cardiotoxicity. In our study, we focused on acute and subacute heart damage. One of the main factors is a genetic predisposition, which determines individual susceptibility to anthracycline cardiotoxicity. The main idea of this study was, for the first time, to evaluate drug metabolism-related genes as a risk factor for developing cardiovascular toxicity in breast cancer patients. The main objective of our study was to identify the impact of drug metabolism-related gene SNPs on the development of subclinical heart damage during and/or after doxorubicin-based chemotherapy in breast cancer patients. The data of 81 women with breast cancer treated with doxorubicin-based chemotherapy in an outpatient clinic were analyzed, and SNP RT-PCR tests were performed. The drug metabolism-related gene variants SULT2B1 rs10426377, UGT1A6 rs17863783, CBR1 rs9024, CBR3 rs1056892, NCF4 rs1883112, and CYBA rs1049255 did not reach a statistically important impact on ABCC in multivariate logistic regression analysis. However, we identified that NCF4 rs1883112 had a risk reduction tendency for ABCC (OR = 0.49, 95% CI 0.27-0.87, p = 0.015). Our findings suggest that some SNPs, such as NCF4 rs1883112, may be associated with a reduced risk of cardiotoxicity, while no variants in this study showed a statistically significant increased risk. Even though, NCF4 rs1883112 showed a risk reduction tendency, suggesting the potential for personalized risk stratification. We can conclude that multiple genes are involved in ABCC, with different impacts, and it is unlikely that there is a single driver gene in ABCC pathogenesis.

Cardiovascular Toxicity in Patients Treated for Childhood Cancer: A Scientific Statement From the American Heart Association

The field of cardio-oncology has expanded over the past 2 decades to address the ever-increasing issues related to cardiovascular disease in patients with cancer and survivors. There is increasing recognition that nearly all cancer treatments pose some short- or long-term risk for development of cardiovascular disease and that pediatric patients with cancer may be especially vulnerable to cardiovascular disease because of young age at treatment and expected long life span afterward. Anthracycline chemotherapy and chest-directed radiotherapy are the most well-studied cardiotoxic therapies, and dose reduction, use of cardioprotection for anthracyclines, and modern radiotherapy approaches have contributed to improved cardiovascular outcomes for survivors. Newer treatments such as small-molecule inhibitors, antibody-based cytotoxic therapy, and immunotherapy have expanded options for previously difficult-to-treat cancers but have also revealed new cardiotoxic profiles. Application of effective surveillance strategies in patients with cancer and survivors has been a focus of practitioners and researchers, whereas the prevention and treatment of extant cardiovascular disease is still developing. Incorporation of new strategies in an equitable manner and appropriate transition from pediatric to adult care will greatly influence long-term health-related outcomes in the growing population of childhood cancer survivors at risk for cardiovascular disease.

Ferroptosis: Latest evidence and perspectives on plant-derived natural active compounds mitigating doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) is a chemotherapy drug widely used in clinical settings, acting as a first-line treatment for various malignant tumors. However, its use is greatly limited by the cardiotoxicity it induces, including doxorubicin-induced cardiomyopathy (DIC). The mechanisms behind DIC are not fully understood, but its potential biological mechanisms are thought to include oxidative stress, inflammation, energy metabolism disorders, mitochondrial damage, autophagy, apoptosis, and ferroptosis. Recent studies have shown that cardiac injury induced by DOX is closely related to ferroptosis. Due to their high efficacy, availability, and low side effects, natural medicine treatments hold strong clinical potential. Currently, natural medicines have been shown to mitigate DOX-induced ferroptosis and ease DIC through various functions such as antioxidation, iron ion homeostasis correction, lipid metabolism regulation, and mitochondrial function improvement. Therefore, this review summarizes the mechanisms of ferroptosis in DIC and the regulation by natural plant products, with the expectation of providing a reference for future research and development of inhibitors targeting ferroptosis in DIC. This review explores the mechanisms of ferroptosis in doxorubicin-induced cardiomyopathy (DIC) and summarizes how natural plant products can alleviate DIC by inhibiting ferroptosis through reducing oxidative stress, correcting iron ion homeostasis, regulating lipid metabolism, and improving mitochondrial function.

Cardioprotective strategies in the management of chemotherapy-induced cardiotoxicity: current approaches and future directions

BACKGROUND

Chemotherapy-induced cardiotoxicity (CIC) is a significant challenge in cancer treatment, leading to heart failure and myocardial infarction. With rising cancer survival rates, the long-term cardiovascular health of survivors has gained importance. While several cardioprotective medications have been studied to mitigate chemotherapy's harmful effects on the heart, more research is needed to confirm their effectiveness and optimal use.

METHODOLOGY

This review synthesizes evidence on cardioprotective drugs in managing CIC. The authors conducted a comprehensive literature search of peer-reviewed articles, clinical trials, and meta-analyses published between January 2000 and May 2024. Studies were selected based on relevance, quality, and focus on mechanisms, efficacy, and clinical outcomes of cardioprotective agents such as beta-blockers, ACE inhibitors, ARBs, statins, and dexrazoxane.

RESULTS AND DISCUSSION

Cardioprotective medications show potential in alleviating the impact of chemotherapy on heart function. Beta-blockers and ACE inhibitors effectively reduce heart failure incidence and improve cardiac outcomes. Statins, with their anti-inflammatory and antioxidative properties, and dexrazoxane, which reduces anthracycline-induced cardiotoxicity, also show promise. However, variability in study designs, patient groups, and chemotherapy treatments complicates the establishment of standardized treatment protocols.

CONCLUSION

Cardioprotective drugs hold significant promise in managing CIC and improving cardiac outcomes for cancer patients. Current evidence supports the efficacy of beta-blockers, ACE inhibitors, statins, and dexrazoxane. Further research is needed to establish standardized protocols, evaluate long-term safety, and optimize treatment timing. Integrating cardioprotective strategies into oncological care can enhance the quality of life and prognosis for cancer survivors.

Iron metabolism in doxorubicin-induced cardiotoxicity: From mechanisms to therapies

Doxorubicin (DOX) is an anti-tumor agent for chemotherapy, but its use is often hindered by the severe and life-threatening side effect of cardiovascular toxicity. In recent years, studies have focused on dysregulated iron metabolism and ferroptosis, a unique type of cell death induced by iron overload, as key players driving the development of DOX-induced cardiotoxicity (DIC). Recent advances have demonstrated that DOX disturbs normal cellular iron metabolism, resulting in excessive iron accumulation and ferroptosis in cardiomyocytes. This review will explore how dysregulated iron homeostasis and ferroptosis drive the progression of DIC. We will also discuss the current approaches to target iron metabolism and ferroptosis to mitigate DIC. Besides, we will discuss the limitations and challenges for clinical translation for these therapeutic regimens.

Risk of anthracycline-induced cardiac dysfunction in adolescent and young adult (AYA) cancer survivors: role of genetic susceptibility loci

There is a known genetic susceptibility to anthracycline-induced cardiac dysfunction in childhood cancer survivors, but this has not been adequately shown in adolescent and young adult (AYA) patients. Our aim was to determine if the previously identified variants associated with cardiac dysfunction in childhood cancer patients affect AYA cancer patients similarly. Forty-five variants were selected for analysis in 253 AYAs previously treated with anthracyclines. We identified four variants that were associated with cardiac dysfunction: SLC10A2:rs7319981 (p = 0.017), SLC22A17:rs4982753 (p = 0.019), HAS3:rs2232228 (p = 0.023), and RARG:rs2229774 (p = 0.050). HAS3:rs2232228 and SLC10A2:rs7319981 displayed significant effects in our AYA cancer survivor population that were in the opposite direction than that reported in childhood cancer survivors. Genetic variants in the host genes were further analyzed for additional associations with cardiotoxicity in AYA cancer survivors. The host genes were then evaluated in a panel of induced pluripotent stem cell-derived cardiomyocytes to assess changes in levels of expression when treated with doxorubicin. Significant upregulation of HAS3 and SLC22A17 expression was observed (p < 0.05), with non-significant anthracycline-responsivity observed for RARG. Our study demonstrates that there is a genetic influence on cardiac dysfunction in AYA cancer patients, but there may be a difference in the role of genetics between childhood and AYA cancer survivors.

Molecular Mechanisms and Therapeutic Targeting of Ferroptosis in Doxorubicin-Induced Cardiotoxicity

Ferroptosis, an iron-dependent form of regulated cell death, has received increasing attention for its pathophysiologic contribution to the onset and development of doxorubicin-induced cardiotoxicity. Moreover, modulation of ferroptosis with specific inhibitors may provide new therapeutic opportunities for doxorubicin-induced cardiotoxicity. Here, we will review the molecular mechanisms and therapeutic promise of targeting ferroptosis in doxorubicin-induced cardiotoxicity.

Priorities in Cardio-Oncology Basic and Translational Science: GCOS 2023 Symposium Proceedings: JACC: CardioOncology State-of-the-Art Review

Despite improvements in cancer survival, cancer therapy-related cardiovascular toxicity has risen to become a prominent clinical challenge. This has led to the growth of the burgeoning field of cardio-oncology, which aims to advance the cardiovascular health of cancer patients and survivors, through actionable and translatable science. In these Global Cardio-Oncology Symposium 2023 scientific symposium proceedings, we present a focused review on the mechanisms that contribute to common cardiovascular toxicities discussed at this meeting, the ongoing international collaborative efforts to improve patient outcomes, and the bidirectional challenges of translating basic research to clinical care. We acknowledge that there are many additional therapies that are of significance but were not topics of discussion at this symposium. We hope that through this symposium-based review we can highlight the knowledge gaps and clinical priorities to inform the design of future studies that aim to prevent and mitigate cardiovascular disease in cancer patients and survivors.

Cardiac electrical abnormalities in childhood acute lymphoblastic leukemia survivors: a systematic review

PURPOSE

The aim was to provide evidence about the prevalence, incidence, and risk factors of cardiac electrical abnormalities in childhood acute lymphoblastic leukemia (ALL) survivors.

METHODS

We included all original studies reporting the incidence and/or prevalence of cardiac electrical abnormalities and/or risk factors associated with cardiac electrical abnormalities in childhood ALL survivors (< 21 years old at the time of their initial cancer diagnosis) who were post-treatment. Searches of the databases PubMed, Ovid MEDLINE(R) and Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations, Daily and Versions(R), Ovid All EBM Reviews, Ovid Embase, and ISI Web of Science were completed in May 2023. The risk of bias was assessed using the standard JBI critical appraisal checklists.

RESULTS

The 11 studies included in this review (N = 1,264 participants) evaluated various parameters, including different cardiac electrical abnormalities. Five studies reported heart rate abnormalities (0-68%), six reported repolarization disorders (0-30%), two reported depolarization disorders (0-1%), seven reported rhythm disturbances or abnormalities (0-100%), four reported conduction disorders (0-10%), and three reported unclassified abnormalities (1-38%). No risk factors were reported.

CONCLUSIONS

Electrical heart problems have been observed in childhood ALL survivors after completion of treatment. Large prospective studies in childhood ALL survivors, clear definitions of cardiac electrical abnormalities, and comparison with a control group are warranted.

IMPLICATIONS FOR CANCER SURVIVORS

Cardiac electrical abnormalities induced by chemotherapy-related cardiotoxicity in the growing population of childhood ALL survivors need to be better characterized to ensure better long-term follow-up and improve overall survival rate.

Prognostic Factors for Cardiotoxicity among Children with Cancer: Definition, Causes, and Diagnosis with Omics Technologies

Improvements in the treatment of childhood cancer have considerably enhanced survival rates over the last decades to over 80% as of today. However, this great achievement has been accompanied by the occurrence of several early and long-term treatment-related complications major of which is cardiotoxicity. This article reviews the contemporary definition of cardiotoxicity, older and newer chemotherapeutic agents that are mainly involved in cardiotoxicity, routine process diagnoses, and methods using omics technology for early and preventive diagnosis. Chemotherapeutic agents and radiation therapies have been implicated as a cause of cardiotoxicity. In response, the area of cardio-oncology has developed into a crucial element of oncologic patient care, committed to the early diagnosis and treatment of adverse cardiac events. However, routine diagnosis and the monitoring of cardiotoxicity rely on electrocardiography and echocardiography. For the early detection of cardiotoxicity, in recent years, major studies have been conducted using biomarkers such as troponin, N-terminal pro b-natriuretic peptide, etc. Despite the refinements in diagnostics, severe limitations still exist due to the increase in the above-mentioned biomarkers only after significant cardiac damage has occurred. Lately, the research has expanded by introducing new technologies and finding new markers using the omics approach. These new markers could be used not only for early detection but also for the early prevention of cardiotoxicity. Omics science, which includes genomics, transcriptomics, proteomics, and metabolomics, offers new opportunities for biomarker discovery in cardiotoxicity and may provide an understanding of the mechanisms of cardiotoxicity beyond traditional technologies.

Circulating hemopexin modulates anthracycline cardiac toxicity in patients and in mice

Anthracyclines such as doxorubicin (Dox) are effective chemotherapies, but their use is limited by cardiac toxicity. We hypothesized that plasma proteomics in women with breast cancer could identify new mechanisms of anthracycline cardiac toxicity. We measured changes in 1317 proteins in anthracycline-treated patients (n = 30) and replicated key findings in a second cohort (n = 31). An increase in the heme-binding protein hemopexin (Hpx) 3 months after anthracycline initiation was associated with cardiac toxicity by echocardiography. To assess the functional role of Hpx, we administered Hpx to wild-type (WT) mice treated with Dox and observed improved cardiac function. Conversely, Hpx-/- mice demonstrated increased Dox cardiac toxicity compared to WT mice. Initial mechanistic studies indicate that Hpx is likely transported to the heart by circulating monocytes/macrophages and that Hpx may mitigate Dox-induced ferroptosis to confer cardioprotection. Together, these observations suggest that Hpx induction represents a compensatory response during Dox treatment.

Role of Iron-Related Oxidative Stress and Mitochondrial Dysfunction in Cardiovascular Diseases

Iron is indispensable in numerous biologic processes, but abnormal iron regulation and accumulation is related to pathological processes in cardiovascular diseases. However, the underlying mechanisms still need to be further explored. Iron plays a key role in metal-catalyzed oxidative reactions that generate reactive oxygen species (ROS), which can cause oxidative stress. As the center for oxygen and iron utilization, mitochondria are vulnerable to damage from iron-induced oxidative stress and participate in processes involved in iron-related damage in cardiovascular disease, although the mechanism remains unclear. In this review, the pathological roles of iron-related oxidative stress in cardiovascular diseases are summarized, and the potential effects and mechanisms of mitochondrial iron homeostasis and dysfunction in these diseases are especially highlighted.

Genetic Susceptibility and Mechanisms Underlying the Pathogenesis of Anthracycline-Associated Cardiotoxicity

Anthracyclines are chemotherapeutic agents widely used to treat a variety of cancers, and these drugs have revolutionized our management of cancer patients. The dose-dependent cardiotoxicity of anthracyclines, however, remains one of the leading causes of chemotherapy treatment-associated mortality in cancer survivors. Patient threshold doses leading to anthracycline-induced cardiotoxicity (AIC) are highly variable among affected patients. This variability is largely ascribed to genetic variants in individuals' genomes. Here, we briefly discuss the prevailing mechanisms underlying the pathogenesis of AIC, and then, we review the genetic variants, mostly identified through human genetic approaches and identified in cancer survivors. The identification of all genetic susceptibilities and elucidation of underlying mechanisms of AIC can help improve upfront risk prediction assessment for potentially severe cardiotoxicity disease and provide valuable insights into the understanding of AIC pathophysiology, which can be further leveraged to develop targeted pharmacogenetic therapies for those at high risk.

Prevention of Anthracycline-Induced Cardiotoxicity: The Good and Bad of Current and Alternative Therapies

Doxorubicin (Dox)-induced cardiotoxicity (DIC) remains a serious health burden, especially in developing countries. Unfortunately, the high cost of current preventative strategies has marginalized numerous cancer patients because of socio-economic factors. In addition, the efficacy of these strategies, without reducing the chemotherapeutic properties of Dox, is frequently questioned. These limitations have widened the gap and necessity for alternative medicines, like flavonoids, to be investigated. However, new therapeutics may also present their own shortcomings, ruling out the idea of “natural is safe”. The U.S. Food and Drug Administration (FDA) has stipulated that the concept of drug-safety be considered in all pre-clinical and clinical studies, to explore the pharmacokinetics and potential interactions of the drugs being investigated. As such our studies on flavonoids, as cardio-protectants against DIC, have been centered around cardiac and cancer models, to ensure that the efficacy of Dox is preserved. Our findings thus far suggest that flavonoids of Galenia africana could be suitable candidates for the prevention of DIC. However, this still requires further investigation, which would focus on drug-interactions as well as in vivo experimental models to determine the extent of cardioprotection.

Shared Genetic Risk Factors Between Cancer and Cardiovascular Diseases

Cancer and cardiovascular diseases (CVD) account for approximately 27.5 million deaths every year. While they share some common environmental risk factors, their shared genetic risk factors are not yet fully understood. The aim of the present study was to aggregate genetic risk factors associated with the comorbidity of cancer and CVDs. For this purpose, we: (1) created a catalog of genes associated with cancer and CVDs, (2) visualized retrieved data as a gene-disease network, and (3) performed a pathway enrichment analysis. We performed screening of PubMed database for literature reporting genetic risk factors in patients with both cancer and CVD. The gene-disease network was visualized using Cytoscape and the enrichment analysis was conducted using Enrichr software. We manually reviewed the 181 articles fitting the search criteria and included 13 articles in the study. Data visualization revealed a highly interconnected network containing a single subnetwork with 56 nodes and 146 edges. Genes in the network with the highest number of disease interactions were JAK2, TTN, TET2, and ATM. The pathway enrichment analysis revealed that genes included in the study were significantly enriched in DNA damage repair (DDR) pathways, such as homologous recombination. The role of DDR mechanisms in the development of CVDs has been studied in previously published research; however, additional functional studies are required to elucidate their contribution to the pathophysiology to CVDs.

Relevance of Ferroptosis to Cardiotoxicity Caused by Anthracyclines: Mechanisms to Target Treatments

Anthracyclines (ANTs) are a class of anticancer drugs widely used in oncology. However, the clinical application of ANTs is limited by their cardiotoxicity. The mechanisms underlying ANTs-induced cardiotoxicity (AIC) are complicated and involve oxidative stress, inflammation, topoisomerase 2β inhibition, pyroptosis, immunometabolism, autophagy, apoptosis, ferroptosis, etc. Ferroptosis is a new form of regulated cell death (RCD) proposed in 2012, characterized by iron-dependent accumulation of reactive oxygen species (ROS) and lipid peroxidation. An increasing number of studies have found that ferroptosis plays a vital role in the development of AIC. Therefore, we aimed to elaborate on ferroptosis in AIC, especially by doxorubicin (DOX). We first summarize the mechanisms of ferroptosis in terms of oxidation and anti-oxidation systems. Then, we discuss the mechanisms related to ferroptosis caused by DOX, particularly from the perspective of iron metabolism of cardiomyocytes. We also present our research on the prevention and treatment of AIC based on ferroptosis. Finally, we enumerate our views on the development of drugs targeting ferroptosis in this emerging field.

Genetics of Anthracycline-Associated Cardiotoxicity

Anthracyclines are a major component of chemotherapies used in many pediatric and adult malignancies. Anthracycline-associated cardiotoxicity (ACT) is a dose-dependent adverse effect that has substantial impact on morbidity and mortality. Therefore, the identification of genetic variants associated with increased risk of ACT has the potential for significant clinical impact to improve patient care. The goal of this review is to summarize the current evidence supporting genetic variants associated with ACT, identify gaps and limitations in current knowledge, and propose future directions for incorporating genetics into clinical practice for patients treated with anthracyclines. We will discuss mechanisms of ACT that could be illuminated by genetics and discuss clinical applications for the cardiologist/cardio-oncologist.

Cardiotoxicity of Anticancer Drugs: Molecular Mechanisms and Strategies for Cardioprotection

Chemotherapy and targeted therapies have significantly improved the prognosis of oncology patients. However, these antineoplastic treatments may also induce adverse cardiovascular effects, which may lead to acute or delayed onset of cardiac dysfunction. These common cardiovascular complications, commonly referred to as cardiotoxicity, not only may require the modification, suspension, or withdrawal of life-saving antineoplastic therapies, with the risk of reducing their efficacy, but can also strongly impact the quality of life and overall survival, regardless of the oncological prognosis. The onset of cardiotoxicity may depend on the class, dose, route, and duration of administration of anticancer drugs, as well as on individual risk factors. Importantly, the cardiotoxic side effects may be reversible, if cardiac function is restored upon discontinuation of the therapy, or irreversible, characterized by injury and loss of cardiac muscle cells. Subclinical myocardial dysfunction induced by anticancer therapies may also subsequently evolve in symptomatic congestive heart failure. Hence, there is an urgent need for cardioprotective therapies to reduce the clinical and subclinical cardiotoxicity onset and progression and to limit the acute or chronic manifestation of cardiac damages. In this review, we summarize the knowledge regarding the cellular and molecular mechanisms contributing to the onset of cardiotoxicity associated with common classes of chemotherapy and targeted therapy drugs. Furthermore, we describe and discuss current and potential strategies to cope with the cardiotoxic side effects as well as cardioprotective preventive approaches that may be useful to flank anticancer therapies.

Divergent Cardiac Effects of Angiotensin II and Isoproterenol Following Juvenile Exposure to Doxorubicin

Hypertension is the most significant risk factor for heart failure in doxorubicin (DOX)-treated childhood cancer survivors. We previously developed a two-hit mouse model of juvenile DOX-induced latent cardiotoxicity that is exacerbated by adult-onset angiotensin II (ANGII)-induced hypertension. It is still not known how juvenile DOX-induced latent cardiotoxicity would predispose the heart to pathologic stimuli that do not cause hypertension. Our main objective is to determine the cardiac effects of ANGII (a hypertensive pathologic stimulus) and isoproterenol (ISO, a non-hypertensive pathologic stimulus) in adult mice pre-exposed to DOX as juveniles. Five-week-old male C57BL/6N mice were administered DOX (4 mg/kg/week) or saline for 3 weeks and then allowed to recover for 5 weeks. Thereafter, mice were administered either ANGII (1.4 mg/kg/day) or ISO (10 mg/kg/day) for 14 days. Juvenile exposure to DOX abrogated the hypertrophic response to both ANGII and ISO, while it failed to correct ANGII- and ISO-induced upregulation in the hypertrophic markers, ANP and BNP. ANGII, but not ISO, worsened cardiac function and exacerbated cardiac fibrosis in DOX-exposed mice as measured by echocardiography and histopathology, respectively. The adverse cardiac remodeling in the DOX/ANGII group was associated with a marked upregulation in several inflammatory and fibrotic markers and altered expression of Ace, a critical enzyme in the RAAS. In conclusion, juvenile exposure to DOX causes latent cardiotoxicity that predisposes the heart to a hypertensive pathologic stimulus (ANGII) more than a non-hypertensive stimulus (ISO), mirroring the clinical scenario of worse cardiovascular outcome in hypertensive childhood cancer survivors.

Iron Promotes Cardiac Doxorubicin Retention and Toxicity Through Downregulation of the Mitochondrial Exporter ABCB8

In several cancers, the efflux and resistance against doxorubicin (DOX), an effective anticancer drug, are associated with cellular iron deficiency and overexpression of the mitochondrial exporter ABCB8. Conversely, decreased ABCB8 expression and disrupted iron homeostasis in the heart have been implicated in DOX-associated cardiotoxicity. While studies have demonstrated that altered iron status can modulate the susceptibility to DOX cardiotoxicity, the exact molecular mechanisms have not been clearly understood. Here, we hypothesized that iron stores influence cardiac ABCB8 expression and consequently cardiac retention and toxicity of DOX. First, we found that ABCB8 deficiency in cardiomyocytes decreased DOX efflux, increased DOX-induced toxicity, and decreased cell viability. Conversely, intracellular DOX retention and toxicity were ameliorated by ABCB8 overexpression. To determine if altered cardiac iron status modifies ABCB8 expression, we treated cardiomyocytes with high iron or iron chelators. Western blot and qPCR analyses revealed that ABCB8 levels were decreased in iron overload and increased in iron deficiency. Subsequently, DOX retention and toxicity were increased in cardiomyocytes with iron overload, whereas iron deficiency ameliorated these effects. Next, we validated our results using a mouse model of hereditary hemochromatosis (HH), a genetic iron overload disorder. HH mice exhibited decreased ABCB8 expression and increased DOX retention and toxicity. These changes were abolished by the treatment of HH mice with a low-iron diet. Finally, cardiac-specific overexpression of ABCB8 in HH mice prevented cardiac DOX accumulation and abrogated DOX-induced cardiotoxicity without altering iron overload in the heart. Together, our results demonstrate that ABCB8 mediates DOX efflux and that iron regulates DOX retention and toxicity by altering cardiac ABCB8 expression. Our study identifies a novel role of iron in DOX-induced cardiotoxicity and suggests potential therapeutic intervention for DOX and anthracycline-based cancer pharmacology.

Pharmacogenomic study of anthracycline-induced cardiotoxicity in Mexican pediatric patients

Background: The aim of this study was to evaluate the association between well-defined genetic risk variants in SLC28A3, RARG and UGT1A6 and anthracycline-induced cardiotoxicity in Mexican pediatric patients. Methods: We tested a cohort of 79 children treated with anthracyclines for the presence of SLC28A3-rs7853758, RARG-rs2229774 and UGT1A6-rs17863783. Results: The SLC28A3-rs7853758 variant was more frequent in this cohort, while the UGT1A6-rs17863783 and RARG-rs2229774 variants were present at lower frequencies. A clinically important decrease of fractional shortening was associated with SLC28A3-rs7853758 variant. Conclusion: In this cohort, 39.2% of patients carried the protective SLC28A3 variant. A small number of tested patients have the risk variants of UGT1A6 and RARG. None of the patients shared the two risk variants.

Juvenile exposure to doxorubicin alters the cardiovascular response to adult-onset psychosocial stress in mice

Childhood cancer survivors have a high risk for premature cardiovascular diseases, mainly due to cardiotoxic cancer treatments such as doxorubicin (DOX). Psychosocial stress is a significant cardiovascular risk factor and an enormous burden in childhood cancer survivors. Although observational studies suggest that psychosocial stress is associated with cardiovascular complications in cancer survivors, there is no translationally relevant animal model to study this interaction. We established a "two-hit" model in which juvenile mice were administered DOX (4 mg/kg/week for 3 weeks), paired to a validated model of chronic subordination stress (CSS) 5 weeks later upon reaching adulthood. Blood pressure, heart rate, and activity were monitored by radio-telemetry. At the end of CSS experiment, cardiac function was assessed by echocardiography. Cardiac fibrosis and inflammation were assessed by histopathologic analysis. Gene expressions of inflammatory and fibrotic markers were determined by PCR. Juvenile exposure to DOX followed by adult-onset CSS caused cardiac fibrosis and inflammation as evident by histopathologic findings and upregulated gene expression of multiple inflammatory and fibrotic markers. Intriguingly, juvenile exposure to DOX blunted CSS-induced hypertension but not CSS-induced tachycardia. There were no significant differences in cardiac function parameters among all groups, but juvenile exposure to DOX abrogated the hypertrophic response to CSS. In conclusion, we established a translationally relevant mouse model of juvenile DOX-induced cardiotoxicity that predisposes to adult-onset stress-induced adverse cardiac remodeling. Psychosocial stress should be taken into consideration in cardiovascular risk stratification of DOX-treated childhood cancer survivors.

Erythropoietin Concentration in Boys With p.His63Asp Polymorphism of the HFE Gene

The molecular mechanism that regulates iron homeostasis is based on a network of signals, which reflect on the iron requirements of the body. HFE-related hemochromatosis is characterized by excessive intestinal absorption of dietary iron, in particular cases resulting in pathologically high iron storage in tissues and organs. During childhood, HFE gene homozygosity or heterozygosity manifests exclusively in the form of biochemical abnormalities. Because of their mutual link, bioavailable iron and endogenous erythropoietin (EPO) are indispensable for effective erythropoiesis. We analyzed the impact of p.(His63Asp) polymorphism of the HFE gene on erythropoiesis taking into consideration endogenous EPO production in the developmental age. In the study we performed, we observed a significant, strong and negative correlation between the concentration of EPO, hemoglobin, and red blood cell count. A negative trend was also noted on the impact of iron concentration and transferrin saturation on EPO production. In conclusion, this preliminary study demonstrates an impaired impact of endogenous EPO on erythropoiesis in the presence of increased iron content in carriers of p.(His63Asp) (heterozygotes) variant of the HFE gene in developmental age.

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.

Pediatric Chemotherapy Drugs Associated With Cardiotoxicity

Pediatric cancers are a common cause of childhood morbidity. As a result, chemotherapeutic regimens have been designed to target childhood cancers. These medications are necessary to treat pediatric cancers, however, oncology management options are accompanied by multiple negative and potentially fatal adverse effects. Although anthracyclines are the most commonly used chemotherapeutic agents associated with cardiotoxicity, we also explore other chemotherapeutic drugs used in children that can potentially affect the heart. Genetic variations resulting in single nucleotide polymorphism (SNP) have the propensity to modify the cardiotoxic effects of the chemotherapy drugs. The clinical presentation of the cardiac effects can vary from arrhythmias and heart failure to completely asymptomatic. A range of imaging studies and laboratory investigations can protect the heart from severe outcomes. The physiology of the heart and the effect of drugs in children vary vividly from adults; therefore, it is crucial to study the cardiotoxic effect of chemotherapy drugs in the pediatric population. This review highlights the potential contributing factors for cardiotoxicity in the pediatric population and discusses the identification and management options.

Genetic basis of anthracyclines cardiotoxicity: Literature review

The purpose of this review was to systematize data on molecular genetic markers of increased risk of cardiotoxic effects, as well as to search for risk and protective variants of candidate genes. Today, the therapy of malignant neoplasms is based on the use of anthracyclines – drugs of the cytostatic mechanism of action. Along with their effectiveness, these drugs can have a cardiotoxic effect on cardiomyocytes by increasing the amount of reactive oxygen species and disrupting mitochondrial biogenesis. Pathological disorders lead to an increased risk of myocardial dysfunction and a number of other cardiovascular pathologies in patients receiving chemotherapy using anthracyclines. The cardiotoxic effect of anthracyclines leads to cardiomyopathy, heart failure, myocardial infarction, and thrombosis. Early detection of cardiotoxic damage leads to reducing the negative effects of these drugs due to changes in chemotherapy tactics. It is known that the risk of cardiotoxic myocardial damage is genetically determined and controlled by more than 80 genes. In this review, the description of basic molecules such as ATP-binding cassette transporters and solute carrier family (SLC transporters), carbonyl reductase, molecules of antioxidant defense, xenobiotic and iron metabolism was performed. In addition, a special attention is paid to the study of epigenetic and post-translational regulation. The available data are characterized by some inconsistency that may be explained by the ethnic differences of the studied populations. Thus, a more detailed research of various ethnic groups, gene-gene interactions between potential candidate genes and epigenetic regulation is necessary. Thus, understanding the contribution of genetic polymorphism to the development of cardiotoxicity will help to assess the individual risks of cardiovascular pathology in patients with various types of cancer, as well as reduce the risk of myocardial damage by developing individual preventive measures and correcting chemotherapy.

Genetic factors in treatment-related cardiovascular complications in survivors of childhood acute lymphoblastic leukemia

Aim: Cardiovascular disease represents one of the main causes of secondary morbidity and mortality in patients with childhood cancer. Patients & methods: To further address this issue, we analyzed cardiovascular complications in relation to common and rare genetic variants derived through whole-exome sequencing from childhood acute lymphoblastic leukemia survivors (PETALE cohort). Results: Significant associations were detected among common variants in the TTN gene, left ventricular ejection fraction (p ≤ 0.0005), and fractional shortening (p ≤ 0.001). Rare variants enrichment in the NOS1, ABCG2 and NOD2 was observed in relation to left ventricular ejection fraction, and in NOD2 and ZNF267 genes in relation to fractional shortening. Following stratification according to risk groups, the modulatory effect of rare variants was additionally found in the CBR1, ABCC5 and AKR1C3 genes. None of the associations was replicated in St-Jude Lifetime Cohort Study. Conclusion: Further studies are needed to confirm whether the described genetic markers may be useful in identifying patients at increased risk of these complications.

Doxorubicin Paradoxically Ameliorates Tumor-Induced Inflammation in Young Mice

Doxorubicin (DOX) is one of the most widely used chemo-therapeutic agents in pediatric oncology. DOX elicits an inflammatory response in multiple organs, which contributes to DOX-induced adverse effects. Cancer itself causes inflammation leading to multiple pathologic conditions. The current study investigated the inflammatory response to DOX and tumors using an EL4-lymphoma, immunocompetent, juvenile mouse model. Four-week old male C57BL/6N mice were injected subcutaneously with EL4 lymphoma cells (5 × 10⁴ cells/mouse) in the flank region, while tumor-free mice were injected with vehicle. Three days following tumor implantation, both tumor-free and tumor-bearing mice were injected intraperitoneally with either DOX (4 mg/kg/week) or saline for 3 weeks. One week after the last DOX injection, the mice were euthanized and the hearts, livers, kidneys, and serum were harvested. Gene expression and serum concentration of inflammatory markers were quantified using real-time PCR and ELISA, respectively. DOX treatment significantly suppressed tumor growth in tumor-bearing mice and caused significant cardiac atrophy in tumor-free and tumor-bearing mice. EL4 tumors elicited a strong inflammatory response in the heart, liver, and kidney. Strikingly, DOX treatment ameliorated tumor-induced inflammation paradoxical to the effect of DOX in tumor-free mice, demonstrating a widely divergent effect of DOX treatment in tumor-free versus tumor-bearing mice.

The genetic underpinnings of anthracycline-induced cardiomyopathy predisposition

Anthracyclines, chemotherapeutic agents that have contributed to significant improvements in cancer survival, also carry risk of both acute and chronic cardiotoxicity. This has led to significantly elevated risks of cardiac morbidity and mortality among cancer survivors treated with these agents. Certain treatment related, demographic, and medical factors increase an individual's risk of anthracycline induced cardiotoxicity; however, significant variability among those affected suggests that there is an underlying genetic predisposition to anthracycline induced cardiotoxicity. The current narrative review seeks to summarize the literature to date that has identified genetic variants associated with anthracycline induced cardiotoxicity. These include variants found in genes that encode proteins associated with anthracycline transportation and metabolism, those that encode proteins associated with the generation of reactive oxygen species, and those known to be associated with cardiac disease. While there is strong evidence that susceptibility to anthracycline induced cardiotoxicity has genetic underpinnings, the majority of work to date has been candidate gene analyses. Future work should focus on genome-wide analyses including genome-wide association and sequencing-based studies to confirm and expand these findings.

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.

Potential Gene Association Studies of Chemotherapy-Induced Cardiotoxicity: A Systematic Review and Meta-Analysis

Chemotherapy is widely used in the treatment of cancer patients, but the cardiotoxicity induced by chemotherapy is still a major concern to most clinicians. Currently, genetic methods have been used to detect patients with high risk of chemotherapy-induced cardiotoxicity (CIC), and our study evaluated the correlation between genomic variants and CIC. The systematic literature search was performed in the PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), China Biology Medicine disc (CBMdisc), the Embase database, China National Knowledge Internet (CNKI) and Wanfang database from inception until June 2020. Forty-one studies were identified that examined the relationship between genetic variations and CIC. And these studies examined 88 different genes and 154 single nucleotide polymorphisms (SNPs). Our study indicated 6 variants obviously associated with the increased risk for CIC, including CYBA rs4673 (pooled odds ratio, 1.93; 95% CI, 1.13–3.30), RAC2 rs13058338 (2.05; 1.11–3.78), CYP3A5 rs776746 (2.15; 1.00–4.62) ABCC1 rs45511401 (1.46; 1.05–2.01), ABCC2 rs8187710 (2.19; 1.38–3.48), and HER2-Ile655Val rs1136201 (2.48; 1.53–4.02). Although further studies are required to validate the diagnostic and prognostic roles of these 6 variants in predicting CIC, our study emphasizes the promising benefits of pharmacogenomic screening before chemotherapy to minimize the CIC.

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.

Regulated cell death pathways in doxorubicin-induced cardiotoxicity

Doxorubicin is a chemotherapeutic drug used for the treatment of various malignancies; however, patients can experience cardiotoxic effects and this has limited the use of this potent drug. The mechanisms by which doxorubicin kills cardiomyocytes has been elusive and despite extensive research the exact mechanisms remain unknown. This review focuses on recent advances in our understanding of doxorubicin induced regulated cardiomyocyte death pathways including autophagy, ferroptosis, necroptosis, pyroptosis and apoptosis. Understanding the mechanisms by which doxorubicin leads to cardiomyocyte death may help identify novel therapeutic agents and lead to more targeted approaches to cardiotoxicity testing.

Use of hiPSC to explicate genomic predisposition to anthracycline-induced cardiotoxicity

The anticancer agents of the anthracycline family are commonly associated with the potential to cause severe toxicity to the heart. To solve the question of why particular a patient is predisposed to anthracycline-induced cardiotoxicity (AIC), researchers have conducted numerous pharmacogenomic studies and identified more than 60 loci associated with AIC. To date, none of these identified loci have been developed into US FDA-approved biomarkers for use in routine clinical practice. With advances in the application of human-induced pluripotent stem cell-derived cardiomyocytes, sequencing technologies and genomic editing techniques, variants associated with AIC can now be validated in a human model. Here, we provide a comprehensive overview of known genetic variants associated with AIC from the perspective of how human-induced pluripotent stem cell-derived cardiomyocytes can be used to help better explain the genomic predilection to AIC.

Cardiovascular and Pulmonary Challenges After Treatment of Childhood Cancer

Childhood cancer survivors are at risk for developing cardiovascular disease and pulmonary disease related to cancer treatment. This might not become apparent until many years after treatment and varies from subclinical to life-threatening disease. Important causes are anthracyclines and radiotherapy involving heart, head, or neck for cardiovascular disease, and bleomycin, busulfan, nitrosoureas, radiation to the chest, and lung or chest surgery for pulmonary disease. Most effects are dose dependent, but genetic risk factors have been discovered. Treatment options are limited. Prevention and regular screening are crucial. Survivors should be encouraged to adopt a healthy lifestyle, and modifiable risk factors should be addressed.

Genetics of Anthracycline Cardiomyopathy in Cancer Survivors: JACC: CardioOncology State-of-the-Art Review

Anthracyclines are an integral part of chemotherapy regimens used to treat a variety of childhood-onset and adult-onset cancers. However, the development of cardiac dysfunction and heart failure often compromises the clinical utility of anthracyclines. The risk of cardiac dysfunction increases with anthracycline dose. This anthracycline-cardiac dysfunction association is modified by several demographic and clinical factors, such as age at anthracycline exposure (<4 years and ≥65 years); female sex; chest radiation; presence of cardiovascular risk factors (diabetes, hypertension); and concurrent use of cyclophosphamide, paclitaxel, and trastuzumab. However, the clinical variables alone yield modest predictive power in detecting cardiac dysfunction. Recently, attention has focused on the molecular basis of anthracycline-related cardiac dysfunction, providing an initial understanding of the mechanism of anthracycline-related cardiomyopathy. This review describes the current state of knowledge with respect to the pathogenesis of anthracycline-related cardiomyopathy and identifies the critical next steps to mitigate this problem.

Pharmacogenomics meets precision cardio-oncology: is there synergistic potential?

An individual's inherited genetic makeup and acquired genomic variants may account for a significant portion of observable variability in therapy efficacy and toxicity. Pharmacogenomics (PGx) is the concept that treatments can be modified to account for these differences to increase chances of therapeutic efficacy while minimizing risk of adverse effects. This is particularly applicable to oncology in which treatment may be multimodal. Each tumor type has a unique genomic signature that lends to inclusion of targeted therapy but may be associated with cumulative toxicity, such as cardiotoxicity, and can impact quality of life. A greater understanding of therapeutic agents impacted by PGx and subsequent implementation has the potential to improve outcomes and reduce risk of drug-induced adverse effects.

Possible Susceptibility Genes for Intervention against Chemotherapy-Induced Cardiotoxicity

Recent therapeutic advances have significantly improved the short- and long-term survival rates in patients with heart disease and cancer. Survival in cancer patients may, however, be accompanied by disadvantages, namely, increased rates of cardiovascular events. Chemotherapy-related cardiac dysfunction is an important side effect of anticancer therapy. While advances in cancer treatment have increased patient survival, treatments are associated with cardiovascular complications, including heart failure (HF), arrhythmias, cardiac ischemia, valve disease, pericarditis, and fibrosis of the pericardium and myocardium. The molecular mechanisms of cardiotoxicity caused by cancer treatment have not yet been elucidated, and they may be both varied and complex. By identifying the functional genetic variations responsible for this toxicity, we may be able to improve our understanding of the potential mechanisms and pathways of treatment, paving the way for the development of new therapies to target these toxicities. Data from studies on genetic defects and pharmacological interventions have suggested that many molecules, primarily those regulating oxidative stress, inflammation, autophagy, apoptosis, and metabolism, contribute to the pathogenesis of cardiotoxicity induced by cancer treatment. Here, we review the progress of genetic research in illuminating the molecular mechanisms of cancer treatment-mediated cardiotoxicity and provide insights for the research and development of new therapies to treat or even prevent cardiotoxicity in patients undergoing cancer treatment. The current evidence is not clear about the role of pharmacogenomic screening of susceptible genes. Further studies need to done in chemotherapy-induced cardiotoxicity.

Cardio-oncology discipline: focus on the necessities in developing countries

Cardiovascular diseases constitute one of the main aetiologies of mortality among patients with cancer. Population ageing and cancer survival rate improvements have resulted in the coexistence of cardiovascular diseases and malignancies in an increasing number of patients. With the diversity in treatments and the introduction of new drug lines, multiple mechanisms of cardiovascular injury have been recognized in these patients. Cardio-oncology is an emerging entity introduced to provide a proper solution to the several challenges encountered in the management of patients with cancer and cardiac involvement. This review will assess the logical grounds for establishing a cardio-oncology unit, describe the main objectives and the detailed responsibilities in such systems, and outline the target population. Furthermore, the importance of research and appropriate data collection will be highlighted. Lastly, the special considerations and modifications required for setting up such centres in the developing countries are discussed.

Prevention of adverse drug effects: a pharmacogenomic approach

PURPOSE OF REVIEW

Adverse drug reactions (ADRs) are a serious burden and can negatively impact patient quality of life. One of these ADRs, anthracycline-induced cardiotoxicity (ACT), occurs in up to 65% of treated patients and can lead to congestive heart failure. Pharmacogenetic studies have helped to reveal the mechanisms of ACT and, consequently, inform current strategies to prevent ACT in the clinic.

RECENT FINDINGS

Many pharmacogenetic studies have been conducted for ACT, but few have led to the development of clinical practice guidelines and clinical genetic testing for ACT. This is, in part, because of lack of replication in independent patient cohorts and/or validation of an affected biological pathway. Recent advances in pharmacogenetic studies have been made through the use of novel methods that directly implicate dysregulated genes and perturbed biological pathways in response to anthracycline treatment.

SUMMARY

Furthering the understanding of the genetics and altered biological pathways of ACT through these novel methods can inform clinical treatment strategies and enable refinement of current clinical practice guidelines. This can therefore lead to improvement in clinical pharmacogenetic testing for further reduction of the incidence of ACT in pediatric cancer patients taking anthracyclines.

Association of GSTM1 null variant with anthracycline-related cardiomyopathy after childhood cancer-A Children's Oncology Group ALTE03N1 report

BACKGROUND

Anthracycline-related cardiomyopathy is a leading cause of late morbidity in childhood cancer survivors. Glutathione S-transferases (GSTs) are a class of phase II detoxification enzymes that facilitate the elimination of anthracyclines. As free-radical scavengers, GSTs could play a role in oxidative damage-induced cardiomyopathy. Associations between the GSTμ1 (GSTM1) null genotype and iron-overload-related cardiomyopathy have been reported in patients with thalassemia.

METHODS

The authors sought to identify an association between the GSTM1 null genotype and anthracycline-related cardiomyopathy in childhood cancer survivors and to corroborate the association by examining GSTM1 gene expression in peripheral blood and human-induced pluripotent stem cell cardiomyocytes (hiPSC-CMs) from survivors with and without cardiomyopathy. GSTM1 gene deletion was examined by polymerase chain reaction in 75 survivors who had clinically validated cardiomyopathy (cases) and in 92 matched survivors without cardiomyopathy (controls). Conditional logistic regression analysis adjusting for sex, age at cancer diagnosis, chest radiation, and anthracycline dose was used to assess the association between genotype and cardiomyopathy. Proprietary bead array technology and quantitative real-time polymerase chain reaction were used to measure GSTM1 expression levels in samples from 20 cases and 20 matched controls. hiPSC-CMs from childhood cancer survivors (3 with cardiomyopathy, 3 without cardiomyopathy) also were examined for GSTM1 gene expression levels.

RESULTS

A significant association was observed between the risk of cardiomyopathy and the GSTM1 null genotype (odds ratio, 2.7; 95% CI, 1.3-5.9; P = .007). There was significant downregulation of GSTM1 expression in cases compared with controls (average relative expression, 0.67 ± 0.57 vs 1.33 ± 1.33, respectively; P = .049). hiPSC-CMs from patients who had cardiomyopathy revealed reduced GSTM1 expression (P = .007).

CONCLUSIONS

The current findings could facilitate the identification of childhood cancer survivors who are at risk for anthracycline-related cardiomyopathy.

Clinical and Research Tools for the Study of Cardiovascular Effects of Cancer Therapy

The expansion of cancer therapeutics has paved the way for improved cancer-related outcomes. Cardiotoxicity from cancer therapy occurs in a small but significant subset of patients, is often poorly understood, and contributes to adverse outcomes at all stages of cancer treatment. Given the often-idiopathic occurrence of cardiotoxicity, novel strategies are needed for risk-stratification and early identification of cancer patients experiencing cardiotoxicity. Clinical and research tools extending from imaging to blood-based biomarkers and pluripotent stem cells are being explored as methods to study the cardiovascular impact of various cancer treatments. Here we provide an overview of tools currently available for evaluation of cardiotoxicity and highlight novel techniques in development aimed at understanding underlying pathophysiologic mechanisms.

Cardiotoxicity - the first cause of morbidity and mortality in pediatric patients survivors of acute lymphoblastic leukemia

Acute lymphoblastic leukemia is the most common hematological malignancy at pediatric age. Cardiotoxicity holds the first place among the causes of morbidity and mortality in these patients. Anthracyclines are cytostatic drugs frequently associated with cardiotoxicity. Early diagnosis of cardiac impairment during the treatment of pediatric patients is extremely important, both for modulating future chemotherapy and for administering cardioprotective agents. Long term monitoring after chemotherapy helps to identify the risk of late cardiotoxicity among cancer survivors. There are several biomarkers, already in use or still under study, which may represent an operator-independent alternative for echocardiography in the diagnosis of cardiotoxicity. In case of cardiac damage, the clinician has options for treating or limiting the progression, either with the use of already approved agents, such as Dexrazoxane, or by administrating other cardioprotective drugs. International experts are still attempting to establish the best algorithm for early detection of cardiotoxicity, as well as the most efficient treatment plan in case of already existing myocardial damage in these patients. We present a review on treatment-related cardiotoxicity, including mechanisms of development, useful biomarkers and treatment options, after carefully analyzing specialty literature.

Anthracycline and Peripartum Cardiomyopathies

Anthracycline-associated cardiomyopathy and peripartum cardiomyopathy are nonischemic cardiomyopathies that often afflict previously healthy young patients; both diseases have been well described since at least the 1970s and both occur in the settings of predictable stressors (ie, cancer treatment and pregnancy). Despite this, the precise mechanisms and the ability to reliably predict who exactly will go on to develop cardiomyopathy and heart failure in the face of anthracycline exposure or childbirth have proven elusive. For both cardiomyopathies, recent advances in basic and molecular sciences have illuminated the complex balance between cardiomyocyte and endothelial homeostasis via 3 broad pathways: reactive oxidative stress, interference in apoptosis/growth/metabolism, and angiogenic imbalance. These advances have already shown potential for specific, disease-altering therapies, and as our mechanistic knowledge continues to evolve, further clinical successes are expected to follow.

Cardiovascular diseases in survivors of childhood cancer

Over the past few decades, the diagnosis and management of children with various malignancies have improved tremendously. As a result, there are an increasing number of children who are long-term cancer survivors. With improved survival, however, has come an increased risk of treatment-related cardiovascular complications that can appear decades after treatment. These problems are serious enough that all caregivers of childhood cancer survivors, including oncologists, cardiologists, and other health care personnel, must pay close attention to the short- and long-term effects of chemotherapy and radiotherapy on these children. This review discusses the effects of treatment-related cardiovascular complications from anthracyclines and radiotherapy and the methods for preventing, screening, and treating these complications.

Keeping heart homeostasis in check through the balance of iron metabolism

Highly active cardiomyocytes need iron for their metabolic activity. In physiological conditions, iron turnover is a delicate process which is dependent on global iron supply and local autonomous regulatory mechanisms. Though less is known about the autonomous regulatory mechanisms, data suggest that these mechanisms can preserve cellular iron turnover even in the presence of systemic iron disturbance. Therefore, activity of local iron protein machinery and its relationship with global iron metabolism is important to understand cardiac iron metabolism in physiological conditions and in cardiac disease. Our knowledge in this respect has helped in designing therapeutic strategies for different cardiac diseases. This review is a synthesis of our current knowledge concerning the regulation of cardiac iron metabolism. In addition, different models of cardiac iron dysmetabolism will be discussed through the examples of heart failure (cardiomyocyte iron deficiency), myocardial infarction (acute changes in cardiac iron turnover), doxorubicin-induced cardiotoxicity (cardiomyocyte iron overload in mitochondria), thalassaemia (cardiomyocyte cytosolic and mitochondrial iron overload) and Friedreich ataxia (asymmetric cytosolic/mitochondrial cardiac iron dysmetabolism). Finally, future perspectives will be discussed in order to resolve actual gaps in knowledge, which should be helpful in finding new treatment possibilities in different cardiac diseases.