Managing chemotherapy-related cardiotoxicity in survivors of childhood cancers

Cardiovascular Considerations After Cancer Therapy: Gaps in Evidence and JACC: CardioOncology Expert Panel Recommendations

Cancer survivors, particularly those treated with anthracyclines and chest radiation, face an elevated risk of cancer therapy-related cardiovascular toxicity. These complications affect not only physical health, but also life expectancy. Risk factors for cancer therapy-related cardiovascular toxicity include age at which cancer treatment was received, the use of (potentially) cardiotoxic cancer therapies, and the presence of concomitant cardiovascular risk factors. Current guidelines provide recommendations for cardiovascular surveillance after cancer therapy, including type and frequency. All cancer survivors are advised to undergo annual clinical screenings and optimization of cardiovascular risk factors. Those at higher risk should undergo additional cardiovascular testing. This document aims to summarize the available evidence, present practical recommendations, and outline existent gaps in the current literature regarding cardiovascular care after cancer therapies.

Echocardiographic Parameters Associated With Cardiorespiratory Fitness and Physical Activity in Childhood Acute Lymphoblastic Leukemia Survivors

BACKGROUND

Children's exposure to chemotherapeutic agents causes several long-term adverse effects but physical activity has been evidenced to be an effective strategy to improve cardiac function. This cross-sectional study aimed to explore the association between physical activity levels, cardiorespiratory fitness, and cardiac parameters measured by echocardiography.

METHODS

Participants were 216n childhood acute lymphoblastic leukemia survivors who underwent a maximal cardiopulmonary exercise test and self-reported their daily minutes of moderate to vigorous physical activity. They underwent a complete transthoracic echocardiographic assessment. Systolic and diastolic function analysis and strain images analysis were performed. The associations were studied through the preventive fraction (examined with univariate crude and adjusted logistic regression models) of regular physical activity (≥150 min·wk-1) and adequate cardiorespiratory fitness levels (above the median ≥ 32.0 mL·kg-1·min-1) on cardiac parameters.

RESULTS

Crude analysis shows that regular physical activity was associated with a significant preventive fraction in mitral E/A ratio (56%; P = .013), while adjusted analyses highlighted a nonsignificant reduction of 74% to 37% in the prevalence of cardiac parameters associated with physical activity. Similar associations of adequate cardiorespiratory fitness on cardiac parameters were observed. Adjusted analyses revealed a nonsignificant reduction of 7% to 86% in the prevalence of cardiac parameters associated with cardiorespiratory fitness.

CONCLUSION

This study reports that regular physical activity and adequate cardiorespiratory fitness were associated with a higher preventive fraction. Thus, engaging in physical activity prevents childhood acute lymphoblastic leukemia survivors' cardiac dysfunctions. These findings are novel and clinically relevant in pediatric cardiooncology and provide additional evidence to strengthen the benefits of exercise as long-term care in childhood cancer survivors.

Cardiorespiratory Fitness and Cardiac Magnetic Resonance Imaging in Childhood Acute Lymphoblastic Leukemia Survivors

BACKGROUND

Childhood acute lymphoblastic leukemia survivors' anthracycline-induced cardiotoxicity could be prevented with good cardiorespiratory fitness levels and regular physical activity. This cross-sectional study aimed to assess the association between cardiorespiratory fitness and physical activity with cardiac magnetic resonance parameters.

METHODS

A total of 96 childhood acute lymphoblastic leukemia survivors underwent a maximal cardiopulmonary exercise test and answered physical activity questionnaires. We calculated the odds ratio of the preventive fraction of regular physical activity (≥150 min/wk) and adequate cardiorespiratory fitness levels (above the median ≥31.4 mL·kg-1·min-1) on cardiac magnetic resonance parameters (left ventricular [LV] and right ventricular [RV] morphological and functional parameters).

RESULTS

An adequate cardiorespiratory fitness was associated with a significant preventive fraction for LV (up to 84% for LV end-diastolic volume) and RV volumes (up to 88% for RV end-systolic volume). The adjusted analyses highlighted a preventive fraction of 36% to 91% between an adequate cardiorespiratory fitness and LV and RV parameters, late gadolinium enhancement fibrosis, and cardiac magnetic resonance relaxation times. No associations were reported with regular physical activity.

CONCLUSIONS

This study provides additional evidence regarding the benefits of an adequate cardiorespiratory fitness level for childhood cancer survivors' cardiac health.

Exposure to Doxorubicin Modulates the Cardiac Response to Isoproterenol in Male and Female Mice

Sex is a salient risk factor in the development of doxorubicin-induced cardiotoxicity. Sex differences in the heart's ability to respond to hypertrophic stimuli in doxorubicin-exposed animals have not been reported. We identified the sexual dimorphic effects of isoproterenol in mice pre-exposed to doxorubicin. Male and female intact or gonadectomized C57BL/6N mice underwent five weekly intraperitoneal injections of 4 mg/kg doxorubicin followed by a five-week recovery period. Fourteen days of subcutaneous isoproterenol injections (10 mg/kg/day) were administered after the recovery period. Echocardiography was used to assess heart function one and five weeks after the last doxorubicin injection and on the fourteenth day of isoproterenol treatment. Thereafter, mice were euthanized, and the hearts were weighed and processed for histopathology and gene expression analysis. Doxorubicin did not produce overt cardiac dysfunction in male or female mice before starting isoproterenol treatment. The chronotropic response to a single isoproterenol injection was blunted by doxorubicin, but the inotropic response was maintained in both males and females. Pre-exposure to doxorubicin caused cardiac atrophy in both control and isoproterenol-treated male mice but not in female mice. Counterintuitively, pre-exposure to doxorubicin abrogated isoproterenol-induced cardiac fibrosis. However, there were no sex differences in the expression of markers of pathological hypertrophy, fibrosis, or inflammation. Gonadectomy did not reverse the sexually dimorphic effects of doxorubicin. Additionally, pre-exposure to doxorubicin abrogated the hypertrophic response to isoproterenol in castrated male mice but not in ovariectomized female mice. Therefore, pre-exposure to doxorubicin caused male-specific cardiac atrophy that persisted after isoproterenol treatment, which could not be prevented by gonadectomy.

SCMR expert consensus statement for cardiovascular magnetic resonance of acquired and non-structural pediatric heart disease

Cardiovascular magnetic resonance (CMR) is widely used for diagnostic imaging in the pediatric population. In addition to structural congenital heart disease (CHD), for which published guidelines are available, CMR is also performed for non-structural pediatric heart disease, for which guidelines are not available. This article provides guidelines for the performance and reporting of CMR in the pediatric population for non-structural ("non-congenital") heart disease, including cardiomyopathies, myocarditis, Kawasaki disease and systemic vasculitides, cardiac tumors, pericardial disease, pulmonary hypertension, heart transplant, and aortopathies. Given important differences in disease pathophysiology and clinical manifestations as well as unique technical challenges related to body size, heart rate, and sedation needs, these guidelines focus on optimization of the CMR examination in infants and children compared to adults. Disease states are discussed, including the goals of CMR examination, disease-specific protocols, and limitations and pitfalls, as well as newer techniques that remain under development.

The Therapeutic Potential of Carnosine as an Antidote against Drug-Induced Cardiotoxicity and Neurotoxicity: Focus on Nrf2 Pathway

Different drug classes such as antineoplastic drugs (anthracyclines, cyclophosphamide, 5-fluorouracil, taxanes, tyrosine kinase inhibitors), antiretroviral drugs, antipsychotic, and immunosuppressant drugs are known to induce cardiotoxic and neurotoxic effects. Recent studies have demonstrated that the impairment of the nuclear factor erythroid 2–related factor 2 (Nrf2) pathway is a primary event in the pathophysiology of drug-induced cardiotoxicity and neurotoxicity. The Nrf2 pathway regulates the expression of different genes whose products are involved in antioxidant and inflammatory responses and the detoxification of toxic species. Cardiotoxic drugs, such as the anthracycline doxorubicin, or neurotoxic drugs, such as paclitaxel, suppress or impair the Nrf2 pathway, whereas the rescue of this pathway counteracts both the oxidative stress and inflammation that are related to drug-induced cardiotoxicity and neurotoxicity. Therefore Nrf2 represents a novel pharmacological target to develop new antidotes in the field of clinical toxicology. Interestingly, carnosine (β-alanyl-l-histidine), an endogenous dipeptide that is characterized by strong antioxidant, anti-inflammatory, and neuroprotective properties is able to rescue/activate the Nrf2 pathway, as demonstrated by different preclinical studies and preliminary clinical evidence. Starting from these new data, in the present review, we examined the evidence on the therapeutic potential of carnosine as an endogenous antidote that is able to rescue the Nrf2 pathway and then counteract drug-induced cardiotoxicity and neurotoxicity.

Genotoxicity, nitric oxide level modulation and cardio-protective potential of Kalanchoe Integra Var. Crenata (Andr.) Cuf Leaves in murine models

ETHNOPHARMACOLOGICAL RELEVANCE

Advancement in cancer therapy has improved survival among patients. However, use of anticancer drugs like anthracyclines (e.g., doxorubicin) is not without adverse effects. Notable among adverse effects of doxorubicin (DOX) is cardiotoxicity, which ranges from mild transient blood pressure changes to potentially serious heart failure. Anecdotal reports suggest that Kalanchoe integra (KI) may have cardio-protective potential.

AIMS OF THE STUDY

This study sought to determine the cardio-protective potential of KI against doxorubicin-induced cardiotoxicity and also examined any possible genotoxic potential of KI in selected organs. Additionally, the nitric oxide modulatory potential of KI was assessed.

MATERIALS AND METHODS

The leaves of KI were collected, air-dried, pulverised and extracted using 70% ethanol. High-performance liquid chromatography (HPLC) fingerprinting was done for KI. Also, the single-cell gel electrophoresis assay (Comet assay) was employed to ascertain the genotoxic potential of KI. In assessment of cardio-protective potential of KI against doxorubicin-induced cardiotoxicity, a total of 42 female Sprague-Dawley rats were put into 7 groups (n = 6). Group I: vehicle control, received normal saline (1 mL/kg p.o) for 30 days. Group II: toxic control, received DOX (20 mg/kg i.p.) once on the 29th day. Group III: KI control, received KI (300 mg/kg p.o) for 30 days. Group IV: vitamin E control, received vitamin E (100 mg/kg p.o) for 30 days. Group V: KI treated-1, received KI (300 mg/kg p.o) for 30 days and DOX (20 mg/kg i.p) on the 29th day. Group VI: KI treated-2, received KI (600 mg/kg p.o) for 30 days and DOX (20 mg/kg i.p) on the 29th day. Group VII: vitamin E treated, received vitamin E (100 mg/kg p.o) for 30 days and DOX (20 mg/kg i.p) on the 29th day. Thirty-six (36) hours after last administration, rats were sacrificed. Blood samples were taken via cardiac puncture to determine levels of aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), lactate dehydrogenase (LDH), enzymatic antioxidants such as glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT). Nitric oxide level was also determined. Hearts of rats in each group were excised and taken through histopathological examination.

RESULTS

In the HPLC fingerprint analysis, 13 peaks were identified, and peak with retention time of 24.0 min had the highest peak area (3.223 x104 mAU). Comet assay showed that the KI extract was non-genotoxic. Pretreatment with KI protected rats against doxorubicin-induced cardiotoxicity as evidenced by the low levels of AST, ALT, ALP, CK and LDH compared with the controls (p < 0.05). SOD, CAT and GPX levels were also high for rats administered KI extracts, further showing that KI protected rats against doxorubicin-induced cardiotoxicity. KI also inhibited nitric oxide levels at 300 mg/kg and 600 mg/kg effective doses. Histological examination revealed that rats pretreated with KI showed no signs of abnormal myocardial fibres (shape, size and configuration).

CONCLUSION

Ethanolic (70%) leaf extract of KI showed no genotoxic potential and possessed cardioprotective effects against doxorubicin-induced cardiotoxicity in Sprague-Dawley rats. KI also inhibited nitric oxide production, thus, a potential nitric oxide scavenger.

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.

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.

Pharmacogenomics insights into precision pediatric oncology

PURPOSE OF REVIEW

Pharmacogenomic insights provide an opportunity to optimize medication dosing regimens and patient outcomes. However, the potential for interindividual genomic variability to guide medication dosing and toxicity monitoring is not yet standard of care. In this review, we present advances for the thiopurines, anthracyclines and vincristine and provide perspectives on the actionability of pharmacogenomic guidance in the future.

RECENT FINDINGS

The current guideline on thiopurines recommends that those with normal predicted thiopurine methyltransferase and NUDT15 expression receive standard-of-care dosing, while 'poor metabolizer' haplotypes receive a decreased 6-mercaptopurine starting dose to avoid bone marrow toxicity. Emerging evidence established significant polygenic contributions that predispose to anthracycline-induced cardiotoxicity and suggest this knowledge be used to identify those at higher risk of complications. In the case of vincristine, children who express CYP3A5 have a significantly reduced risk of peripheral neuropathy compared with those expressing an inactive form or the CYP3A4 isoform.

SUMMARY

The need for adequately powered pediatric clinical trials, coupled with the study of epigenetic mechanisms and their influence on phenotypic variation and the integration of precision survivorship into precision approaches are featured as important areas for focused investments in the future.

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.

Resveratrol reduces cardiac NLRP3-inflammasome activation and systemic inflammation to lessen doxorubicin-induced cardiotoxicity in juvenile mice

Doxorubicin (DOX) is a very effective anticancer agent that is widely used in pediatric cancer patients. Nevertheless, DOX is known to have cardiotoxic effects that may progress to cardiomyopathy later in life. We have recently shown that cotreatment of resveratrol (RES) with DOX in juvenile mice attenuates late-onset hypertension-induced cardiomyopathy. However, the molecular mechanism responsible for these changes remains unknown. Herein, we show that the cardiac NLRP3 inflammasome plays a crucial role in regulating cardiac injury in a DOX -treated juvenile mouse model and the detrimental effects of hypertension in these mice later in life. We further demonstrate that RES significantly reduces systemic inflammation to contribute to the improvements observed in DOX -induced cardiac injury in young mice and late-onset hypertension-induced cardiomyopathy.

Pediatric Restrictive Cardiomyopathies

Restrictive cardiomyopathy (RCM) is the least frequent phenotype among pediatric heart muscle diseases, representing only 2.5-3% of all cardiomyopathies diagnosed during childhood. Pediatric RCM has a poor prognosis, high incidence of pulmonary hypertension (PH), thromboembolic events, and sudden death, is less amenable to medical or surgical treatment with high mortality rates. In this scenario, heart transplantation remains the only successful therapeutic option. Despite a shared hemodynamic profile, characterized by severe diastolic dysfunction and restrictive ventricular filling, with normal ventricle ejection fraction and wall thickness, RCM recognizes a broad etiological spectrum, consisting of genetic/familial and acquired causes, each of which has a distinct pathophysiology and natural course. Hence, the aim of this review is to cover the causes, clinical presentation, diagnostic evaluation, treatment, and prognosis of pediatric RCM.

Is there scope for better individualisation of anthracycline cancer chemotherapy?

Anthracyclines are used to treat solid and haematological cancers, particularly breast cancers, lymphomas and childhood cancers. Myelosuppression and cardiotoxicity are the primary toxicities that limit treatment duration and/or intensity. Cardiotoxicity, particularly heart failure, is a leading cause of morbidity and mortality in cancer survivors. Cumulative anthracycline dose is a significant predictor of cardiotoxicity risk, suggesting a role for anthracycline pharmacokinetic variability. Population pharmacokinetic modelling in children has shown that doxorubicin clearance in the very young is significantly lower than in older children, potentially contributing to their higher risk of cardiotoxicity. A model of doxorubicin clearance based on body surface area and age offers a patient-centred dose-adjustment strategy that may replace the current disparate initial-dose selection tools, providing a rational way to compensate for pharmacokinetic variability in children aged <7 years. Population pharmacokinetic models in adults have not adequately addressed older ages, obesity, hepatic and renal dysfunction, and potential drug-drug interactions to enable clinical application. Although candidate gene and genome-wide association studies have investigated relationships between genetic variability and anthracycline pharmacokinetics or clinical outcomes, there have been few clinically significant reproducible associations. Precision-dosing of anthracyclines is currently hindered by lack of clinically useful pharmacokinetic targets and models that predict cumulative anthracycline exposures. Combined with known risk factors for cardiotoxicity, the use of advanced echocardiography and biomarkers, future validated pharmacokinetic targets and predictive models could facilitate anthracycline precision dosing that truly maximises efficacy and provides individualised early intervention with cardioprotective therapies in patients at risk of cardiotoxicity.

The effect of adenosine triphosphate on sunitinib-induced cardiac injury in rats

In this study, we aimed to show the effect of adenosine 5'-triphosphate (ATP) on sunitinib-induced cardiac injury in rats. The rats (n = 30) were divided equally into three groups as sunitinib group (SG), sunitinib plus ATP group (SAG), and healthy group (HG); 2 mg/kg ATP was injected intraperitoneally (ip) to the SAG group. Same volume normal saline as solvent was administered ip to the other two groups. After 1 h, 25 mg/kg sunitinib was applied orally via catheter to stomach in the SAG and SG groups. This procedure was repeated once daily for 5 weeks. At the end of this period, all animals were sacrificed and their cardiac tissue was removed. Malondialdehyde (MDA), total glutathione (tGSH), tumor necrosis factor α (TNF-α), and nuclear factor κB (NF-κB) levels in rats' cardiac tissues and troponin I (Tp-I) levels in rats' blood samples were evaluated. Histopathological analysis was also performed in cardiac tissues of the animals. MDA, TNF-α, NF-κB, and Tp-I levels were higher in the SG group compared to the SAG and HG groups (p < 0.001). tGSH levels of the SG group were lower than the SAG and HG groups (p < 0.001). The structure and morphology of cardiac muscle fibers and blood vessels were normal in the control group. In the SG group, obvious cardiac muscle tissue damage with dilated myofibers, locally atrophic myofibers, and congested blood vessels were observed. In the SAG group, marked amelioration in these findings was observed. We showed this for the first time that ATP administration exerts a protective effect against cardiac effects of sunitinib.

Subclinical Cardiac Dysfunction in Childhood Cancer Survivors on 10-Years Follow-Up Correlates With Cumulative Anthracycline Dose and Is Best Detected by Cardiopulmonary Exercise Testing, Circulating Serum Biomarker, Speckle Tracking Echocardiography, and Tissue Doppler Imaging

Background: Survivors of childhood cancer are at risk for anthracycline- and/or radiotherapy-induced cardiotoxicity. Aims: The aim of this study was to assess clinical, laboratory, and imaging parameters of subclinical cardiovascular disease in childhood cancer survivors. Methods: Patients underwent cardiopulmonary exercise test (CPET), laboratory testing, transthoracic echocardiography (TTE) with tissue doppler imaging (TDI) and speckle tracking. A subset of patients also underwent cardiovascular magnetic resonance imaging (CMR). Findings were correlated to cumulative anthracycline and exposure to mediastinal irradiation during cancer treatment. In a subgroup analysis, TTE and CMR findings were compared to data from 40 gender- and age-matched patients with childhood onset hypertrophic cardiomyopathy (HCM). Results: Cardiac evaluation was performed in 79 patients (43 males) at 11.2 ± 4.5 years after cancer treatment. Oncologic diagnosis at a median age of 12.0 years was Hodgkin lymphoma in 20, sarcoma in 17, acute leukemia in 24, relapse leukemia in 10, and others in 8 patients. Cumulative anthracycline dose exceeded 300 mg/m² in 28 patients. Twenty six patients also received mediastinal irradiation. Decreased peak respiratory oxygen uptake in % predicted on CPET, increased levels of N-terminal pro-brain natriuretic peptide (NTproBNP), increased global longitudinal strain on TTE speckle tracking, and diastolic dysfunction on TDI were the most prominent findings on detailed cardiology follow-up. In contrast to HCM patients, childhood cancer survivors did not show left ventricular hypertrophy (LVPWd z-score median 0.9 vs. 2.8, p < 0.001), hyperdynamic systolic function on TTE (Ejection fraction 62 ± 7 vs. 72 ± 12%, p = 0.001), or fibrotic myocardial changes on CMR (Late gadolinium positive 0/13 vs. 13/36, p = 0.001; extracellular volume fraction 22 ± 2 vs. 28 ± 3, p < 0.001) at time of follow-up. There was no correlation between chest radiation exposure and abnormal cardiac findings. Cumulative anthracycline dose was the only significant independent predictor on multivariate analysis for any cardiovascular abnormality on follow-up (p = 0.036). Conclusion: Increasing cumulative anthracycline dose during cancer treatment correlates with subclinical cardiac dysfunction in childhood cancer survivors best detected by elevated cardiac serum biomarkers, decreased exercise capacity on CPET, and abnormalities on echocardiographic speckle tracking and TDI.

Health Status in Long-Term Survivors of Hepatoblastoma

The aim of this study was to evaluate the health status of children cured from hepatoblastoma. Forty-five patients with hepatoblastoma treated between 1996–2014 were assessed. The recorded data included sex, age at diagnosis, disease stage, treatment methods, time since diagnosis, and the evaluation of health status domains which included performance status, growth development, hearing, cardiovascular, skeletal, gastrointestinal, genitourinary, neurological, and hematological function. There were 30 boys and 15 girls. The age at diagnosis ranged from one month to 14 years (median one year). At the time of the health status evaluation, the youngest patient was 5.5 years old and the oldest was 21 years of age (median—10 years). All patients were treated according to the Childhood Liver Tumors Strategy Group—SIOPEL recommendations, though they were not active participants of the studies. The median cumulative dose of cisplatin was 520 mg/m² and 360 mg/m² for doxorubicin. Thirty-six patients underwent partial hepatectomy, and nine total hepatectomy and liver transplantation. At a median of nine years from diagnosis, 68% of hepatoblastoma survivors had experienced at least one chronic health condition of any grade. The most frequent late complication was ototoxicity (28.8%), and the most serious were second malignancies (6.6%) and cardiomyopathy (4.4%). Conclusion: Survivors of hepatoblastoma are at risk for long-term complications. They require long-term monitoring for late effects.

Closing the survivorship gap in children and adolescents with Hodgkin lymphoma

The treatment of Hodgkin lymphoma (HL) is one of early success. However, disease-free survival (DFS) does not reflect latent organ injury and its impact on health status and well-being beyond 5 years. In fact, we are at a crossroads, in terms of needing individualized approaches to maintain DFS, while minimizing late effects and preserving health-related quality of life (HRQoL). Premature morbidity and mortality translate to a high societal cost associated with the potential number of productive life years ahead in this population who are young at diagnosis. The discordance between short-term lymphoma-free survival and long-term health and HRQoL creates a "survivorship gap" which can be characterized for individuals and for subgroups of patients. The current review delineates contributors to compromised outcomes and health status in child and adolescent (paediatric) HL and frames the survivorship gap in terms of primary and secondary prevention. Primary prevention aims to titrate therapy. Secondary prevention entails strategies to intervene against late effects. Bridging the survivorship gap will be attained with enhanced knowledge of and attention to biology of the tumour and microenvironment, host genetic factors, HRQoL and sub-populations with disparate outcomes.

Co-administration of resveratrol with doxorubicin in young mice attenuates detrimental late-occurring cardiovascular changes

Aims

Doxorubicin (DOX) is among the most effective chemotherapies used in paediatric cancer patients. However, the clinical utility of DOX is offset by its well-known cardiotoxicity, which often does not appear until later in life. Since hypertension significantly increases the risk of late-onset heart failure in childhood cancer survivors, we investigated whether juvenile DOX exposure impairs the ability to adapt to angiotensin II (Ang II)-induced hypertension later in life and tested a treatment that could prevent this.

Methods and results

Five-week-old male mice were administered a low dose of DOX (4 mg/kg) or saline once a week for 3 weeks and then allowed to recover for 5 weeks. Following the 5-week recovery period, mice were infused with Ang II or saline for 2 weeks. In another cohort, mice were fed chow containing 0.4% resveratrol 1 week before, during, and 1 week after the DOX administrations. One week after the last DOX administration, p38 mitogen-activated protein kinase (MAPK) was activated in hearts of DOX-treated mice demonstrating molecular signs of cardiac stress; yet, there was no change in cardiac function between groups. However, DOX-treated mice failed to develop compensatory cardiac hypertrophy in response to Ang II-induced hypertension later in life. Of importance, mice receiving DOX with resveratrol co-administration displayed normalization in p38 MAPK activation in the heart and a restored capacity for cardiac hypertrophy in response to Ang II-induced hypertension.

Conclusion

We have developed a juvenile mouse model of DOX-induced cardiotoxicity that displays no immediate overt physiological dysfunction; but, leads to an impaired ability of the heart to adapt to hypertension later in life. We also show that co-administration of resveratrol during DOX treatment was sufficient to normalize molecular markers of cardiotoxicity and restore the ability of the heart to undergo adaptive remodelling in response to hypertension later in life.

Cardiomyopathy in Children: Classification and Diagnosis: A Scientific Statement From the American Heart Association

In this scientific statement from the American Heart Association, experts in the field of cardiomyopathy (heart muscle disease) in children address 2 issues: the most current understanding of the causes of cardiomyopathy in children and the optimal approaches to diagnosis cardiomyopathy in children. Cardiomyopathies result in some of the worst pediatric cardiology outcomes; nearly 40% of children who present with symptomatic cardiomyopathy undergo a heart transplantation or die within the first 2 years after diagnosis. The percentage of children with cardiomyopathy who underwent a heart transplantation has not declined over the past 10 years, and cardiomyopathy remains the leading cause of transplantation for children >1 year of age. Studies from the National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry have shown that causes are established in very few children with cardiomyopathy, yet genetic causes are likely to be present in most. The incidence of pediatric cardiomyopathy is ≈1 per 100 000 children. This is comparable to the incidence of such childhood cancers as lymphoma, Wilms tumor, and neuroblastoma. However, the published research and scientific conferences focused on pediatric cardiomyopathy are sparcer than for those cancers. The aim of the statement is to focus on the diagnosis and classification of cardiomyopathy. We anticipate that this report will help shape the future research priorities in this set of diseases to achieve earlier diagnosis, improved clinical outcomes, and better quality of life for these children and their families.

Optimizing Cardiovascular Care in Children With Acute Myeloid Leukemia to Improve Cancer-Related Outcomes

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice. A 14-year-old African American female presented with fatigue, easy bruising, and fever. On examination, she had scattered bruising, lymphadenopathy, and hepatosplenomegaly. Laboratory evaluation revealed pancytopenia with peripheral blasts, and acute myeloid leukemia (AML; French-American-British M2, t[8;21][q22;q22.1]) was diagnosed on bone marrow biopsy. A baseline echocardiogram revealed normal left ventricular (LV) systolic function (ejection fraction [EF], 60%; shortening fraction [SF], 32%), and conventional chemotherapy was initiated that consisted of two cycles of remission induction (cytarabine, etoposide, and daunorubicin [50 mg/m² × 3 days per cycle]) followed by intensification 1 (high-dose cytarabine and etoposide), intensification 2 (high-dose cytarabine and mitoxantrone [12 mg/m²/dose daily; four total doses]), and intensification 3 (high-dose cytarabine and l-asparaginase). Of note, an echocardiogram was not repeated before the start of intensification 1. During intensification 1, the patient developed Streptococcus viridans sepsis, which required 4 days in the intensive care unit with antimicrobial and inotropic support. Repeat echocardiogram after recovery from the sepsis episode demonstrated low-normal LV systolic function (EF, 53%; SF, 27%), and she subsequently began intensification 2. On day 3 of intensification 2, the patient developed afebrile tachypnea, tachycardia, and an increasing oxygen requirement. Chest x-ray revealed cardiomegaly and pulmonary vascular congestion. Cardiac troponins were normal, whereas N-terminal pro B-type natriuretic peptide was 10 times the upper limit of normal. Repeat echocardiogram showed an enlarged LV with moderate to severely depressed LV function (EF, 28%; SF, 14%). Day 4 mitoxantrone was omitted and a cardiology consult obtained.

Identification of a novel microRNA profile in pediatric patients with cancer treated with anthracycline chemotherapy

Anthracycline chemotherapy (AC) is associated with decline in left ventricular ejection fraction (LVEF), yet the mechanisms remain unclear. Although changes in microRNAs (miRs) have been identified in adult cardiovascular disease, miR profiles in pediatric patients with AC have not been well studied. The goal of this study was to examine miR profiles (unbiased array) in pediatric patients with AC compared with age-matched referent normal patients. We hypothesize that pediatric patients with AC will express a unique miR profile at the initiation and completion of therapy and will be related to LVEF. Serum was collected in pediatric patients (10–22 yr, n = 12) with newly diagnosed malignancy requiring AC within 24–48 h after the initiation of therapy (30–60 mg/m2) and ~1 yr after completing therapy. A custom microarray of 84 miRs associated with cardiovascular disease was used (quantitative RT-PCR) and indexed to referent normal profiles (13–17 yr, n = 17). LVEF was computed by cardiac MRI. LVEF fell from AC initiation at ~1 yr after AC completion (64.28 ± 1.78% vs. 57.53 ± 0.95%, respectively, P = 0.004). Of the 84 miRs profiled, significant shifts in 17 miRs occurred relative to referent normal ( P ≤ 0.05). Moreover, the functional domain of miRs associated with myocardial differentiation and development fell over threefold at the completion of AC ( P ≤ 0.05). Moreover, eight miRs were significantly downregulated after AC completion in those patients with the greatest decline in LVEF (≥10%, P < 0.05). This study demonstrates, for the first time, that changes in miR expression occur in pediatric patients with AC. These findings suggest that miRs are a potential strategy for the early identification of patients with AC susceptible to left ventricular dysfunction.

NEW & NOTEWORTHY Although anthracycline chemotherapy (AC) is effective for a number of pediatric cancers, an all too often consequence of AC is the development of left ventricular failure. The present study identified that specific shifts in the pattern of microRNAs, which regulate myocardial growth, function, and viability, occurred during and after AC in pediatric patients, whereby the magnitude of this shift was associated with the degree of left ventricular failure.

Circulating microRNAs: Potential Markers of Cardiotoxicity in Children and Young Adults Treated With Anthracycline Chemotherapy

Background

Biomarkers for early detection of anthracycline (AC)‐induced cardiotoxicity may allow cardioprotective intervention before irreversible damage. Circulating microRNAs (miRNAs) are promising biomarkers of cardiovascular disease, however, have not been studied in the setting of AC‐induced cardiotoxicity. This study aimed to identify AC‐induced alterations in plasma miRNA expression in children and correlate expression with markers of cardiac injury.

Methods and Results

Candidate plasma profiling of 24 miRNAs was performed in 33 children before and after a cycle of AC (n=24) or noncardiotoxic chemotherapy (n=9). Relative miRNA changes between the pre‐ and postcycle time points (6, 12, and 24 hours) were determined within each treatment group and compared across groups. Plasma miRNA expression patterns were further explored with respect to AC dose and high‐sensitivity troponin T. Greater chemotherapy‐induced dysregulation was observed in this panel of candidate, cardiac‐related plasma miRNAs in patients receiving anthracyclines compared with those receiving noncardiotoxic chemotherapy (24‐hour MANOVA; P=0.024). Specifically, plasma miRs‐29b and ‐499 were upregulated 6 to 24 hours post‐AC, and their postchemotherapy expression significantly correlated with AC dose. Patients with acute cardiomyocyte injury (high‐sensitivity troponin T increase ≥5 ng/L from baseline) demonstrated higher expression of miR‐29b and miR‐499 post‐AC compared with those without.

Conclusions

In this pilot study, cardiac‐related plasma miRNAs are dysregulated following ACs. Plasma miR‐29b and ‐499 are acutely elevated post‐AC, with dose response relationships observed with anthracycline dose and markers of cardiac injury. Further evaluation of miRNAs may provide mechanistic insight into AC‐induced cardiotoxicity and yield biomarkers to facilitate earlier intervention to mitigate cardiotoxicity.

Biochemical and electrocardiographic studies on the beneficial effects of gallic acid in cyclophosphamide-induced cardiorenal dysfunction

Background Cardiac toxicity is one of the life-threatening complications of cancer therapy. Cyclophosphamide (CYP) is an alkylating agent with potent antineoplastic and immunosuppressive properties and possibly the most widely used antineoplastic agent. Chronic cardiotoxicity associated with CYP is characterized by progressive heart failure developing from weeks to years after therapy. Methods In this study, rats were administered with (60 mg/kg and 120 mg/kg) alone or in combination with single intraperitoneal (200 mg/kg) administration of CYP for 7 days. CYP was only administered on day 1. Results The administration of CYP led to a significant (p<0.05) increase in cardiac and renal malondialdehyde (MDA) contents and hydrogen peroxide (H2O2) generation. Also, the activities of catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and reduced glutathione (GSH) levels were significantly (p<0.05) reduced following CYP treatment. A significant (p<0.05) increase in serum myeloperoxidase (MPO) activity was recorded in rats administered CYP only. Electrocardiogram (ECG) showed a significant (p<0.05) increase in heart rate (HR) accompanied by transient decrease in QRS duration. Histologic examination revealed architectural anarchy of both heart and kidney of rats that received only CYP. Conclusions In this study, treatment with gallic acid (60 mg/kg and 120 mg/kg) restored the enzymic and non-enzymic antioxidants and also attenuated cardiotoxic and nephrotoxic effect of CYP through free radical scavenging activity, anti-inflammatory and improvement of antioxidant defence system.

Prevention of cardiotoxicity among survivors of childhood cancer

LINKED ARTICLES

This article is part of a joint Themed section with the British Journal of Pharmacology on Cardiotoxicity. The rest of the Themed section will appear in a future issue of BJP and will be available at http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1476-5381 The number of survivors of childhood cancers has increased exponentially over the past few decades. However, these survivors are also at substantially increased long-term risk of morbidity and mortality, especially from treatment-related cardiotoxicity. Preventing these risks is now a priority when treating children and adolescents with cancer. Dexrazoxane reduces the risk of anthracycline-induced cardiotoxicity among adults and children with cancer without reducing its antineoplastic effects or event-free survival. Thus, it should be strongly considered as a part of therapy for children and adolescents treated with anthracyclines.

Progress on the cardiotoxicity of sunitinib: Prognostic significance, mechanism and protective therapies

Tyrosine kinase inhibitors (TKIs) are multi-targeted anti-cancer agents effective in the treatment of renal cell carcinoma (RCC), imatinib-resistant gastrointestinal stromal tumor (GIST) and pancreatic cancer (PC). Targeting and inhibiting a wide range of oncogenically relevant receptor tyrosine kinases (RTKs), TKIs have been the golden standard treatment of several types of cancer. The cardiotoxicity of TKIs, however, has also emerged alongside their anti-cancer potencies and has attracted research attention. Over the past few years significant progress has been made in developing a deeper understanding of aspects such as extent of cardiotoxicity, prognostic implications and survival predictions, toxicological mechanisms, and potential cardioprotective therapies. In this review we focus on a typical TKI sunitinib and summarize the up-to-date knowledge of sunitinib-induced cardiac abnormalities reported in clinical studies, weighing their implications of prognostic values. We also examine recent findings in underlying mechanisms, and development of potential cardioprotective agents.

The interplay between genetic background and sexual dimorphism of doxorubicin-induced cardiotoxicity

Background

Doxorubicin (DOX) is a very effective anticancer medication that is commonly used to treat hematological malignancies and solid tumors. Nevertheless, DOX is known to have cardiotoxic effects that may lead to cardiac dysfunction and failure. In experimental studies, female animals have been shown to be protected against DOX-induced cardiotoxicity; however, the evidence of this sexual dimorphism is inconclusive in clinical studies. Therefore, we sought to investigate whether genetic background could influence the sexual dimorphism of DOX-induced cardiotoxicity.

Methods

Male and female Wistar Kyoto (WKY) and Spontaneous Hypertensive Heart Failure (SHHF) rats were used. DOX was administered in eight doses of 2 mg/kg/week and the rats were followed for an additional 12 weeks. Cardiac function was assessed by trans-thoracic echocardiography, systolic blood pressure was measured by the tail cuff method, and heart and kidney tissues were collected for histopathology.

Results

Female sex protected against DOX-induced weight loss and increase in blood pressure in the WKY rats, whereas it protected against DOX-induced cardiac dysfunction and the elevation of cardiac troponin in SHHF rats. In both strains, female sex was protective against DOX-induced nephrotoxicity. There was a strong correlation between DOX-induced renal pathology and DOX-induced cardiac dysfunction.

Conclusions

This study highlights the importance of studying the interaction between sex and genetic background to determine the risk of DOX-induced cardiotoxicity. In addition, our findings suggest that DOX-induced nephrotoxicity may play a role in DOX-induced cardiac dysfunction in rodent models.

The roles of microRNAs in the pathogenesis and drug resistance of chronic myelogenous leukemia (Review)

Chronic myeloid leukemia (CML) is characterized by the accumulation of Philadelphia chromosome-positive (Ph+) myeloid cells. Ph+ cells occur via a reciprocal translocation between the long arms of chromosomes 9 and 22 resulting in constitutively active BCR-ABL fusion protein. Tyrosine kinase inhibitors (TKIs) are used against the kinase activity of BCR-ABL protein for the effective treatment of CML. However, the development of drug resistance, caused by different genetic mechanisms, is the major issue in the clinical application of TKIs. These mechanisms include changes in expression levels of microRNAs (miRNAs). miRNAs are short non-coding regulatory RNAs that control gene expression and play an important role in cancer development and progression. In the present review, we highlight the roles of miRNAs both in the progression and chemotherapy-resistance of CML. Our understanding of these mechanisms may lead to the use of this knowledge not only in the treatment of patients with CML, but also in other type of cancers.

Identification of novel biomarkers for doxorubicin-induced toxicity in human cardiomyocytes derived from pluripotent stem cells

Doxorubicin is a chemotherapeutic agent indicated for the treatment of a variety of cancer types, including leukaemia, lymphomas, and many solid tumours. The use of doxorubicin is, however, associated with severe cardiotoxicity, often resulting in early discontinuation of the treatment. Importantly, the toxic symptoms can occur several years after the termination of the doxorubicin administration. In this study, the toxic effects of doxorubicin exposure have been investigated in cardiomyocytes derived from human embryonic stem cells (hESC). The cells were exposed to different concentrations of doxorubicin for up to 2 days, followed by a 12 day recovery period. Notably, the cell morphology was altered during drug treatment and the cells showed a reduced contractile ability, most prominent at the highest concentration of doxorubicin at the later time points. A general cytotoxic response measured as Lactate dehydrogenase leakage was observed after 2 days’ exposure compared to the vehicle control, but this response was absent during the recovery period. A similar dose-dependant pattern was observed for the release of cardiac specific troponin T (cTnT) after 1 day and 2 days of treatment with doxorubicin. Global transcriptional profiles in the cells revealed clusters of genes that were differentially expressed during doxorubicin exposure, a pattern that in some cases was sustained even throughout the recovery period, suggesting that these genes could be used as sensitive biomarkers for doxorubicin-induced toxicity in human cardiomyocytes. The results from this study show that cTnT release can be used as a measurement of acute cardiotoxicity due to doxorubicin. However, for the late onset of doxorubicin-induced cardiomyopathy, cTnT release might not be the most optimal biomarker. As an alternative, some of the genes that we identified as differentially expressed after doxorubicin exposure could serve as more relevant biomarkers, and may also help to explain the cellular mechanisms behind the late onset apoptosis associated with doxorubicin-induced cardiomyopathy.