Monitoring chemotherapy-induced cardiotoxicity: role of cardiac nuclear imaging

The role of inflammation and antioxidant defenses in the cardiotoxicity of doxorubicin in elderly CD-1 male mice

Doxorubicin (DOX) is a potent chemotherapeutic agent used against several cancer types. However, due to its cardiotoxic adverse effects, the use of this drug may be also life-threatening. Although most cancer patients are elderly, they are poorly represented and evaluated in pre-clinical and clinical studies. Considering this, the present work aims to evaluate inflammation and oxidative stress as the main mechanisms of DOX-induced cardiotoxicity, in an innovative approach using an experimental model constituted of elderly animals treated with a clinically relevant human cumulative dose of DOX. Elderly (18-20 months) CD-1 male mice received biweekly DOX administrations, for 3 weeks, to reach a cumulative dose of 9.0 mg/kg. One week (1W) or two months (2 M) after the last DOX administration, the heart was collected to determine both drug's short and longer cardiac adverse effects. The obtained results showed that DOX causes cardiac histological damage and fibrosis at both time points. In the 1W-DOX group, the number of nuclear factor kappa B (NF-κB) p65 immunopositive cells increased and a trend toward increased NF-κB p65 expression was seen. An increase of inducible nitric oxide synthase (iNOS) and interleukin (IL)-33 and a trend toward increased IL-6 and B-cell lymphoma-2-associated X (Bax) expression were seen after DOX. In the same group, a decrease in IL-1β, p62, and microtubule-associated protein 1A/1B-light chain 3 (LC3)-I, p38 mitogen-activated protein kinase (MAPK) expression was observed. Contrariwise, the animals sacrificed 2 M after DOX showed a significant increase in glutathione peroxidase 1 and Bax expression with persistent cardiac damage and fibrosis, while carbonylated proteins, erythroid-2-related factor 2 (Nrf2), NF-κB p65, myeloperoxidase, LC3-I, and LC3-II expression decreased. In conclusion, our study demonstrated that in an elderly mouse population, DOX induces cardiac inflammation, autophagy, and apoptosis in the heart in the short term. When kept for a longer period, oxidative-stress-linked pathways remained altered, as well as autophagy markers and tissue damage after DOX treatment, emphasizing the need for continuous post-treatment cardiac monitoring.

Molecular Imaging Biomarkers in Cardiooncology: A View on Established Technologies and Future Perspectives

Novel therapeutic options have significantly improved survival and long-term outcomes in many cancer entities. Unfortunately, this improvement in outcome is often accompanied by new and increasingly relevant therapy-related cardiovascular toxicity. In this context, cardiooncology has emerged as a new field of interdisciplinary individual patient care. Important tasks are pretherapeutic risk stratification and early detection and treatment of cardiotoxicity, which comprises cardiac damage in relation to cardiovascular comorbidities, the tumor disease, and cancer treatment. Clinical manifestations can cover a broad spectrum, ranging from subtle and usually asymptomatic abnormalities to serious acute or chronic complications. Typical manifestations include acute and chronic heart failure, myo- and pericarditis, arrythmias, ischemia, and endothelial damage. They can be related to almost all current cancer treatments, including cytotoxic chemotherapy, targeted therapy, immunotherapy, hormonal therapy, and radiotherapy. Molecular imaging biomarkers can aid in pretherapeutic cardiooncologic assessment for primary prevention and personalized surveillance, detection, and differential diagnosis of cardiotoxic complications. Potential advantages over conventional diagnostics are the higher detection sensitivity for subtle changes in cardiac homeostasis, higher reproducibility, and better observer independence. Hybrid imaging with highly sensitive PET/MRI may be particularly suited for early diagnosis. Important technologies that are encouraged in current multidisciplinary guidelines are equilibrium radionuclide angiography for evaluation of ventricular function and chamber morphology, as well as myocardial perfusion imaging for additional detection of ischemia. Novel modalities that may detect even earlier signs of cardiotoxicity comprise 123I-metaiodobenzylguanidine SPECT to visualize sympathetic innervation, 18F-FDG and somatostatin receptor (68Ga-DOTATOC/DOTATATE) PET to indicate a metabolic shift and inflammation, and 68Ga-fibroblast activation protein inhibitor PET to monitor cardiac remodeling. In addition, PET imaging of mitochondrial function has recently been introduced in preclinical models and will potentially broaden the field of application through higher sensitivity and specificity and by enabling higher individualization of diagnostic concepts.

Early detection of cancer therapy cardiotoxicity by radionuclide angiography: An update

Cancer therapy-induced cardiotoxicity is an emerging clinical and healthcare issue. Myocardial dysfunction and heart failure are mostly responsible for increased cardiovascular mortality in cancer disease survivors. Several imaging surveillance techniques have been proposed for early diagnosis of cancer therapy-induced cardiac dysfunction. Our aim was to provide an update of radionuclide angiography applications in this field. Radionuclide angiography is widely used to assess left ventricular ejection fraction (LVEF) throughout cancer treatment, especially in patients with limited acoustic window. Additional prognostic data may be provided by phase analysis and diastolic function evaluation. Low LVEF and high approximate entropy at baseline seem to be predictors for cancer therapy-induced cardiac dysfunction. A decrease in peak filling rate and/or an increase in time to peak filling rate may be observed in patients undergoing anthracycline and/or trastuzumab administration. Diastolic function impairment may precede or not LVEF decrease. In conclusion, recent studies have provided novel insights into the possible role of radionuclide angiography in the early detection of cancer therapy cardiotoxicity. While interpreting the results of a radionuclide angiography examination, an integrated approach combining the evaluation of LVEF, LV diastolic function, and phase analysis may be useful to improve risk stratification of cancer patients treated with cardiotoxic agents.

Nuclear medicine in the assessment and prevention of cancer therapy-related cardiotoxicity: prospects and proposal of use by the European Association of Nuclear Medicine (EANM)

Cardiotoxicity may present as (pulmonary) hypertension, acute and chronic coronary syndromes, venous thromboembolism, cardiomyopathies/heart failure, arrhythmia, valvular heart disease, peripheral arterial disease, and myocarditis. Many of these disease entities can be diagnosed by established cardiovascular diagnostic pathways. Nuclear medicine, however, has proven promising in the diagnosis of cardiomyopathies/heart failure, and peri- and myocarditis as well as arterial inflammation. This article first outlines the spectrum of cardiotoxic cancer therapies and the potential side effects. This will be complemented by the definition of cardiotoxicity using non-nuclear cardiovascular imaging (echocardiography, CMR) and biomarkers. Available nuclear imaging techniques are then presented and specific suggestions are made for their application and potential role in the diagnosis of cardiotoxicity.

MIBG cardiac imaging compared to ejection fraction in evaluation of cardiotoxicity: a systematic review

BACKGROUND

Advances in diagnosis and treatment of cancer has improved survival but resulted in increased cardiotoxic effects. The decrease in left ventricular ejection fraction (EF), one of the pillars of diagnosis of cardiotoxicity, seems to be a late process in the evolution of the disease, so 123I-metaiodobenzylguanidine (MIBG) cardiac imaging has been proposed to detect early cardiac impairment. The aim of this systematic review was to evaluate the performance of MIBG cardiac scan in this scenario.

METHODS AND RESULTS

A systematic search was conducted in five international databases comparing MIBG parameters with EF for evaluation of cardiotoxicity. Twelve studies were included and separated in three groups. First, studies evaluating patients with established cardiotoxicity, in which EF was reduced and MIBG parameters were abnormal. Second, studies analyzing patients during or after treatment compared to controls, with MIBG parameters significantly different between groups in most studies, even when EF remained normal. Finally, studies analyzing anthracycline (ATC) dose-related changes, with alteration in MIBG parameters occurring even when EF was preserved.

CONCLUSION

Although studies had high methodological variability, cardiac sympathetic innervation imaging seems to be a promising tool for assessing early cardiotoxicity. Further studies are needed to analyze its diagnostic value in this scenario.

Detection of Anticancer Drug-Induced Cardiotoxicity Using VCAM1-Targeted Nanoprobes

Chemotherapy-induced cardiac toxicity is an undesirable yet very common effect that increases the risk of death and reduce the quality of life of individuals undergoing chemotherapy. However, no feasible methods and techniques are available to monitor and detect the degree of cardiotoxicity at an early stage. Therefore, in this project, we aim to develop a fluorescent nanoprobe to image the toxicity within the cardiac tissue induced by an anticancer drug. We have observed that vascular cell adhesion molecule 1 (VCAM1) protein alone with collagen was overly expressed within the heart, when an animal was treated with doxorubicin (DOX), because of inflammation in the epithelial cells. We hypothesize that developing a VCAM1-targeted peptide-based (VHPKQHRGGSKGC) fluorescent nanoprobe can detect and visualize the affected heart. In this regard, we prepared a poly(lactic-co-glycolic acid) (PLGA) nanoparticle linked with VCAM1 peptide and rhodamine B (PLGA-VCAM1-RhB). Selective binding and higher accumulation of the PLGA-VCAM1-RhB nanoprobes were detected in DOX-treated human cardiomyocyte cells (HCMs) compared to the untreated cells. For in vivo studies, DOX (5 mg/kg) was injected via the tail vein once in two weeks for 6 weeks (3 injection total). PLGA-VCAM1-RhB and PLGA-RhB were injected via the tail vein after 1 week of the last dose of DOX, and images were taken 4 h after administration. A higher fluorescent signal of PLGA-RhB-VCAM-1 (48.62% ± 12.79%) was observed in DOX-treated animals compared to the untreated control PLGA-RhB (10.61% ± 4.90) within the heart, indicating the specificity and targeting ability of PLGA-VCAM1-RhB to the inflamed tissues. The quantified fluorescence intensity of the homogenized cardiac tissue of PLGA-RhB-VCAM1 showed 156% higher intensity than the healthy control group. We conclude that PLGA-VCAM1-RhB has the potential to bind inflamed cardiac cells, thereby detecting DOX-induced cardiotoxicity and damaged heart at an early stage.

Cardiac functional imaging

During the last 20 years, cardiac imaging has drastically evolved. Positron emission tomography (PET), fast three-dimensional (3D) imaging with the latest generations of echocardiography & multi-detector computed tomography (CT), stress perfusion assessed by magnetic resonance imaging (MRI), blood flow analysis using four-dimensional (4D) flow MRI, all these techniques offer new trends for optimal noninvasive functional cardiac imaging. Dynamic functional imaging is obtained by acquiring images of the heart at different phases of the cardiac cycle, allowing assessment of cardiac motion, function, and perfusion. Between CT and Cardiac MRI (CMR), CMR has the best temporal resolution, which is suitable for functional imaging while cardiac CT provides higher spatial resolution with isotropic data that have an identical resolution in the three dimensions of the space. The latest generations of CT scanners enable whole heart assessment in one beat, offering also an acceptable temporal resolution with the possibility to display the images in a dynamic mode. Another rapidly growing technique using functional and molecular imaging for the assessment of biological and metabolic pathways is the PET using radio-labeled tracers. Meanwhile, the oldest cardiac imaging tool with doppler ultrasound technology has never stopped evolving. Echocardiography today performs 3D imaging, stress perfusion, and myocardial strain assessment, with high temporal resolution. It still is the first line and more accessible exam for the patient. These different modalities are complementary and may be even combined into PET-CT or PET-MRI. The ability to combine the functional/molecular data with anatomical images may implement a new dimension to our diagnostic tools.

Doxorubicin-induced apoptosis enhances monocyte infiltration and adverse cardiac remodeling in diabetic animals

Diabetic cancer patients were treated with doxorubicin (DOX), a potent chemotherapeutic drug that induces cardiac toxicity; however, molecular mechanisms of cardiac toxicity in this specific disease progression in patients and animal models are completely unknown. Therefore, we designed a study to understand the effects of DOX-induced cardiac toxicity in diabetic animals and the involved pathophysiological mechanisms. C57BL/6 J mice were divided into four DOX- and diabetic (streptozotocin; STZ) - treated groups; control, STZ, DOX, and DOX+STZ. At day 14, animals were sacrificed, echocardiography was used to examine heart function, and heart and blood samples were collected to investigate apoptotic mechanisms (caspase 3, BAX, B-Cell leukemia/lymphoma 2 (Bcl2)), inflammation, and cardiac remodeling. Our data shows a significant (p < 0.05) increase in glucose levels, apoptotic markers, and monocyte infiltration at the site of apoptosis and triggered inflammatory immune response (tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6)), in DOX+STZ animals compared with control and experimental groups. We also observed significant (p < 0.05) increase in myofibrillar area, fibrosis, and significantly decreased (p < 0.05) cardiac function in DOX-treated diabetic animals compared with controls. In conclusion, our data suggest that DOX induces significantly increased apoptosis, fibrosis, and structural alterations in diabetic hearts compared with non-diabetic animals.

Shining Damaged Hearts: Immunotherapy-Related Cardiotoxicity in the Spotlight of Nuclear Cardiology

The emerging use of immunotherapies in cancer treatment increases the risk of immunotherapy-related cardiotoxicity. In contrast to conventional chemotherapy, these novel therapies have expanded the forms and presentations of cardiovascular damage to a broad spectrum from asymptomatic changes to fulminant short- and long-term complications in terms of cardiomyopathy, arrythmia, and vascular disease. In cancer patients and, particularly, cancer patients undergoing (immune-)therapy, cardio-oncological monitoring is a complex interplay between pretherapeutic risk assessment, identification of impending cardiotoxicity, and post-therapeutic surveillance. For these purposes, the cardio-oncologist can revert to a broad spectrum of nuclear cardiological diagnostic workup. The most promising commonly used nuclear medicine imaging techniques in relation to immunotherapy will be discussed in this review article with a special focus on the continuous development of highly specific molecular markers and steadily improving methods of image generation. The review closes with an outlook on possible new developments of molecular imaging and advanced image evaluation techniques in this exciting and increasingly growing field of immunotherapy-related cardiotoxicity.

Personality Traits and Cardiotoxicity Arising From Cancer Treatments: An Hypothesized Relationship

Thanks to the evolution in medical and pharmaceutical research, to date, the number of cancer treatments is increasingly on the rise. Despite this, several side effects related to cancer treatments can exacerbate patients’ physical and psychological conditions, such as cardiotoxicity. Over the years, researchers have explored the possible relationship between psychological variables and physical diseases. Even though some authors examined the relationship between personality and specific diseases, no scientific attention has been paid to the role of personality in the development of cardiotoxicity arising from cancer treatments. Yet this is an important objective, given that determining whether personality influences cardiac toxicity of anticancer treatments could inform the processes by which stable psychological factors influence health. This contribution summarizes and analyzes the available scientific evidence about the association between personality and main cardiotoxicity-related-diseases of anticancer therapies, including cancer and cardiovascular diseases, in order to sketch a hypothetical model of the relationship between personality traits and cardiotoxicity.

Insights into Doxorubicin-induced Cardiotoxicity: Molecular Mechanisms, Preventive Strategies, and Early Monitoring

Doxorubicin (DOX) is one of the most effective anticancer drugs to treat various forms of cancers; however, its therapeutic utility is severely limited by its associated cardiotoxicity. Despite the enormous amount of research conducted in this area, the exact molecular mechanisms underlying DOX toxic effects on the heart are still an area that warrants further investigations. In this study, we reviewed literature to gather the best-known molecular pathways related to DOX-induced cardiotoxicity (DIC). They include mechanisms dependent on mitochondrial dysfunction such as DOX influence on the mitochondrial electron transport chain, redox cycling, oxidative stress, calcium dysregulation, and apoptosis pathways. Furthermore, we discuss the existing strategies to prevent and/or alleviate DIC along with various techniques available for therapeutic drug monitoring (TDM) in cancer patients treated with DOX. Finally, we propose a stepwise flowchart for TDM of DOX and present our perspective at curtailing this deleterious side effect of DOX.

Cardiovascular imaging in cardio-oncology

Cancer therapy may lead to cardiovascular complications and can promote each aspect of cardiac disease manifestation, such as vascular disease including coronary heart disease, myocardial diseases including heart failure, structural heart diseases including valvular heart diseases, and rhythm disorders. All potential complications of cancer therapy onto the cardiovascular system require imaging for diagnostic workup as well as monitoring of therapy. Transthoracic echocardiography (TTE) is the most frequently used tool for assessment of cardiac function during or after cancer therapy in daily clinical routine. With modern techniques like strain analysis, echocardiography allows to detect a variety of cardiac diseases as caused by cancer therapy even at subclinical stages. For further workup, specific imaging techniques including nuclear imaging are needed in a multimodality imaging approach to in detail characterize the underlying pathophysiology and to improve the management of the patients. Therefore, the field of imaging in cardio-oncology is rapidly growing. This review article will give an overview about existing literature regarding the role of imaging in the diagnostic evaluation and management of therapy in patient with prior or ongoing cancer therapy.

Methods of diagnosis in cardio-oncology

Early diagnosis and advances in treatment have led to improved survival of patients with cancer, but have also increased morbidity and mortality due to treatment side effects. Cardiovascular diseases (CVDs) are one of the most frequent of these side effects. As a result of the direct effects of radiation therapy and chemotherapy on heart and vessels сan be: acceleration of atherosclerosis, damage of cardiomyocytes and endothelium, and arterial and venous thrombosis. The direct effect of the cancer treatment on the heart is called cardiotoxicity. Early diagnosis and identification of patients at high risk of cardiotoxicity is the first step towards successful prevention of CVD in cancer patients without compromising cancer care, which ultimately leads to a reduction in mortality. Echocardiography is the method of choice for the detection of myocardial dysfunction during and after cancer therapy. New methods of imaging like three-dimensional echocardiography, speckle-tracking echocardiography, cardiac magnetic resonance show a higher sensitivity in detecting of early myocardial dysfunction during cancer therapy. This review outlines the main diagnostic algorithms and approaches used in cardiooncology.

Apoptosis and remodeling in adriamycin-induced cardiomyopathy rat model

Purpose

The mechanism for the pathogenesis of adriamycin (ADR)-induced cardiomyopathy is not yet known. Different hypotheses include the production of free radicals, an interaction between ADR and nuclear components, and a disruption in cardiac-specific gene expression. Apoptosis has also been proposed as being involved in cardiac dysfunction. The purpose of this study was to determine if apoptosis might play a role in ADR-induced cardiomyopathy.

Methods

Male Sprague-Dawley rats were separated into 2 groups: the control group (C group) and the experimental group (ADR 5 mg/wk for 3 weeks through intraperitoneal injections; A group). Echocardiographic images were obtained at week 3. Changes in caspase-3, B-cell leukemia/lymphoma (Bcl)-2, Bcl-2-associated X (Bax), interleukin (IL)-6, tumor necrosis factor-α, brain natriuretic peptide (BNP), troponin I, collagen 1, and collagen 3 protein expression from the left ventricle tissues of C and A group rats were determined by Western blot.

Results

Ascites and heart failure as well as left ventricular hypertrophy were noted in the A group. Ejection fraction and shortening fraction were significantly lower in the A group by echocardiography. The expression of caspase-3, Bax, IL-6, BNP, collagen 1, and collagen 3 were significantly higher in the A group as compared with the C group. Protein expression of Bcl-2 decreased significantly in the A group compared with the C group.

Conclusion

ADR induced an upregulation of caspase-3, Bax, IL-6, and collagen, as well as a depression in Bcl-2. Thus, apoptosis and fibrosis may play an important role in ADR-induced cardiomyopathy.

Cardio-Oncology - A new subspecialty with collaboration at its heart

Cardio-Oncology is the care of cancer patients with cardiovascular disease, overt or occult, already established or acquired during treatment. Cancer patients can present with a variety of cardiovascular problems not all of which are directly related to cancer therapy (medications or radiotherapy). The cardiovascular problems of oncology patients can range from ischaemia to arrhythmias and can also include valve problems and heart failure. As such, within cardiology, teamwork is required with members of different cardiology subspecialties. The way forward will be to adopt a multidisciplinary approach to produce optimal individual care. Close collaboration between cardiology and oncology specialists in a Cardio-Oncology setting can make this happen.

Diagnostic Strategies for Early Recognition of Cancer Therapeutics-Related Cardiac Dysfunction

Cardiovascular toxicity in the form of cardiac dysfunction continues to be an obstacle for patients with cancer. Survival and quality of life of cancer survivors are frequently affected by increased incidence of cardiovascular disease. The involvement of the cardiovascular system by primary or secondary malignancies, as well as its dysfunction secondary to the administration of antineoplastics, has led to the development of a new discipline called Cardio-Oncology, an exciting cardiology subspecialty with more questions than answers and as a result an enormous opportunity for research in the field. Multidisciplinary efforts have been focused on the prevention, diagnosis, and treatment of cancer therapeutics-related cardiovascular dysfunction (CTRCD). This review article will focus on the early diagnosis of left ventricular dysfunction associated with chemotherapy. Currently, the identification of cardiac toxicity associated with cancer treatment is the cornerstone for critical decisions regarding anticancer therapy and cardioprotective strategies. Its early detection, especially in subclinical phases, allows immediate intervention to prevent further impairment of the myocardium and other cardiovascular structures. The most significant published studies were selected for this revision, providing an updated document for the health professionals involved in the care of patients with cancer. We examined the current evidence and recommendations for biochemical and noninvasive diagnostic techniques, including their specific role for identification of CTRCD. Traditional and advanced imaging modalities, used alone or in combination with cardiovascular biomarkers, are essential for the recognition of cardiotoxicity during cancer therapy. Evolving basic and clinical research are focused on the development of more sensitive and specific diagnostic tools and for the recognition of cardiac toxicity.

Cardiovascular imaging in the diagnosis and monitoring of cardiotoxicity: cardiovascular magnetic resonance and nuclear cardiology

Chemotherapy-induced cardiotoxicity (CTX) is a determining factor for the quality of life and mortality of patients administered potentially cardiotoxic drugs and in long-term cancer survivors. Therefore, prevention and early detection of CTX are highly desirable, as is the exploration of alternative therapeutic strategies and/or the proposal of potentially cardioprotective treatments. In recent years, cardiovascular imaging has acquired a pivotal role in this setting. Although echocardiography remains the diagnostic method most used to monitor cancer patients, the need for more reliable, reproducible and accurate detection of early chemotherapy-induced CTX has encouraged the introduction of second-line advanced imaging modalities, such as cardiac magnetic resonance (CMR) and nuclear techniques, into the clinical setting. This review of the Working Group on Drug Cardiotoxicity and Cardioprotection of the Italian Society of Cardiology aims to afford an overview of the most important findings from the literature about the role of CMR and nuclear techniques in the management of chemotherapy-treated patients, describe conventional and new parameters for detecting CTX from both diagnostic and prognostic perspectives and provide integrated insight into the role of CMR and nuclear techniques compared with other imaging tools and versus the positions of the most important international societies.

Assessment of late anthracycline-induced cardiotoxicity by 123I-mIBG cardiac scintigraphy in patients treated during childhood and adolescence

PURPOSE

The goal of this study was to evaluate late cardiotoxic effects of anthracyclines (ATC) by evaluating cardiac sympathetic activity in a cohort of asymptomatic patients previously treated with ATC for childhood cancers.

METHODS

We studied 89 asymptomatic patients previously treated with ATC with a normal echocardiogram (49 men and 40 women) and a control group of 40 healthy individuals (26 men and 14 women). Both groups underwent planar myocardial 123I-meta-iodobenzylguanidine scintigraphy (123I-mIBG). From these images, the early and late heart-to-mediastinum (H/M) ratio and washout rate (WR) were assessed.

RESULTS

The mean survival at the time of the 123I-mIBG scintigraphy was 5.3 ± 3.4 years. Patients treated with ATC had a lower but clinical normal left ventricular ejection fraction (LVEF) compared to controls (60.44 ± 6.5 vs 64.1 ± 6.0%, P < 0.01). Both the late H/M ratio and WR were not able to discriminate ATC treated patients from controls. The cumulative ATC dose was the only independent predictor of the LVEF, explaining approximately 12% of the variation in LVEF (P = 0.01).

CONCLUSIONS

Although the pathophysiology behind ATC cardiotoxicity is most likely multifactorial, myocardial sympathetic activity is not associated with a reduction in LVEF 5-years after completion of chemotherapy.

Substantial Increase in Myocardial FDG Uptake on Interim PET/CT May Be an Early Sign of Adriamycin-Induced Cardiotoxicity

Cumulative cardiotoxicity is a well-established adverse effect of Adriamycin therapy. Although dose dependent, cardiotoxicity has been recently reported to occur even at lower doses than usually proposed. Conventional imaging detection and/or clinical manifestation of the deterioration in cardiac function occur late in the process; thus, it is desirable to have noninvasive markers to detect toxicity at an early stage. Several biochemical markers including troponin and atrial natriuretic peptide were explored for this purpose. The present case depicts that a significant increase in myocardial FDG uptake on posttherapy PET/CT can be a potential imaging biomarker of Adriamycin-induced cardiotoxicity.

Doxorubicin induced heart failure: Phenotype and molecular mechanisms

Long term survival of childhood cancers is now more than 70%. Anthracyclines, including doxorubicin, are some of the most efficacious anticancer drugs available. However, its use as a chemotherapeutic agent is severely hindered by its dose-limiting toxicities. Most notably observed is cardiotoxicity, but other organ systems are also degraded by doxorubicin use. Despite the years of its use and the amount of information written about this drug, an understanding of its cellular mechanisms is not fully appreciated. The mechanisms by which doxorubicin induces cytotoxicity in target cancer cells have given insight about how the drug damages cardiomyocytes. The major mechanisms of doxorubicin actions are thought to be as an oxidant generator and as an inhibitor of topoisomerase 2. However, other signaling pathways are also invoked with significant consequences for the cardiomyocyte. Further the interaction between oxidant generation and topoisomerase function has only recently been appreciated and the consequences of this interaction are still not fully understood. The unfortunate consequences of doxorubicin within cardiomyocytes have promoted the search for new drugs and methods that can prevent or reverse the damage caused to the heart after treatment in cancer patients. Alternative protocols have lessened the impact on newly diagnosed cancer patients. However the years of doxorubicin use have generated a need for monitoring the onset of cardiotoxicity as well as understanding its potential long-term consequences. Although a fairly clear understanding of the short-term pathologic mechanisms of doxorubicin actions has been achieved, the long-term mechanisms of doxorubicin induced heart failure remain to be carefully delineated.

Multimodality Imaging in Cardiooncology

Cardiotoxicity represents a rising problem influencing prognosis and quality of life of chemotherapy-treated patients. Anthracyclines and trastuzumab are the drugs most commonly associated with development of a cardiotoxic effect. Heart failure, myocardial ischemia, hypertension, myocarditis, and thrombosis are typical manifestation of cardiotoxicity by chemotherapeutic agents. Diagnosis and monitoring of cardiac side-effects of cancer treatment is of paramount importance. Echocardiography and nuclear medicine methods are widely used in clinical practice and left ventricular ejection fraction is the most important parameter to asses myocardial damage secondary to chemotherapy. However, left ventricular ejection decrease is a delayed phenomenon, occurring after a long stage of silent myocardial damage that classic imaging methods are not able to detect. New imaging techniques including three-dimensional echocardiography, speckle tracking echocardiography, and cardiac magnetic resonance have demonstrated high sensitivity in detecting the earliest alteration of left ventricular function associated with future development of chemotherapy-induced cardiomyopathy. Early diagnosis of cardiac involvement in cancer patients can allow for timely and adequate treatment management and the introduction of cardioprotective strategies.

Effect of recombinant human erythropoietin on mitomycin C-induced oxidative stress and genotoxicity in rat kidney and heart tissues

Mitomycin C (MMC) is an antineoplastic agent used for the treatment of several human malignancies. Nevertheless, the prolonged use of the drug may result in a serious heart and kidney injuries. Recombinant human erythropoietin (rhEPO) has recently been shown to exert an important cytoprotective effect in experimental brain injury and ischemic acute renal failure. The aim of the present work is to investigate the cardioprotective and renoprotective effects of rhEPO against MMC-induced oxidative damage and genotoxicity. Our results showed that MMC induced oxidative stress and DNA damage. rhEPO administration in any treatment conditions decreased oxidative damage induced by MMC. It reduced malondialdehyde and protein carbonyl levels. rhEPO ameliorated reduced glutathione plus oxidized glutathione modulation and the increased catalase activity after MMC treatment. Furthermore, rhEPO restored DNA damage caused by MMC. We concluded that rhEPO administration especially in pretreatment condition protected rats against MMC-induced heart and renal oxidative stress and genotoxicity.

Nuclear imaging in detection and monitoring of cardiotoxicity

Cardiotoxicity as a result of cancer treatment is a novel and serious public health issue that has a significant impact on a cancer patient’s management and outcome. The coexistence of cancer and cardiac disease in the same patient is more common because of aging population and improvements in the efficacy of antitumor agents. Left ventricular dysfunction is the most typical manifestation and can lead to heart failure. Left ventricular ejection fraction measurement by echocardiography and multigated radionuclide angiography is the most common diagnostic approach to detect cardiac damage, but it identifies a late manifestation of myocardial injury. Early non-invasive imaging techniques are needed for the diagnosis and monitoring of cardiotoxic effects. Although echocardiography and cardiac magnetic resonance are the most commonly used imaging techniques for cardiotoxicity assessment, greater attention is focused on new nuclear cardiologic techniques, which can identify high-risk patients in the early stage and visualize the pathophysiologic process at the tissue level before clinical manifestation. The aim of this review is to summarize the role of nuclear imaging techniques in the non-invasive detection of myocardial damage related to antineoplastic therapy at the reversible stage, focusing on the current role and future perspectives of nuclear imaging techniques and molecular radiotracers in detection and monitoring of cardiotoxicity.

Imaging of early modification in cardiomyopathy: the doxorubicin-induced model

Doxorubicin chemotherapy is effective and widely used to treat acute lymphoblastic leukemia. However, its effectiveness is hampered by a wide spectrum of dose-dependent cardiotoxicity including both morphological and functional changes, affecting primarily the myocardium. Non-invasive imaging techniques are used for the diagnosis and monitoring of these cardiotoxic effects. The purpose of this review is to summarize and compare the most common imaging techniques used in early detection and therapeutic monitoring of doxorubicin-induced cardiotoxicity and the suggested mechanisms of such side effects. Imaging techniques using echocardiography including conventional 2D and 3D echocardiography along with MRI sequences including Tagging, Cine, and quantitative MRI in detecting early myocardial damage are also reviewed. As there is a multitude of reported indices and imaging methods to assess particular functional alterations, we limit this review to the most relevant techniques based on their clinical application and their potential to early detection of doxorubicin-induced cardiotoxic effects.

Traditional and novel methods to assess and prevent chemotherapy-related cardiac dysfunction noninvasively

The field of cardio-oncology is challenged to address an ever greater spectrum of cardiotoxicity associated with combination chemotherapy, greater dose intensity, extremes of age, and enhanced patient survival which exposes more protracted risk of developing congestive heart failure (CHF). Recent reports of chemotherapy-induced hypertension as a common adverse effect of angiogenesis inhibitors and immunosuppressants clarify the need for routine blood pressure (BP) monitoring and guideline-based management of hypertension as an integral strategy to preserve LV function. Serial monitoring of radionuclide left ventricular ejection fraction (LVEF) in adults and echocardiography in children continues to provide outcome based, cost-effective prevention of CHF in high risk patients receiving chemotherapy. To optimize treatment and monitoring strategies to eliminate late-onset LV dysfunction and CHF, traditional and novel candidate methods for assessment of chemotherapy-induced LV dysfunction are reviewed. These include serial assessment of LV volume indices by gated SPECT ERNA and gated SPECT MPI, 3D echocardiography and contrast 2D echocardiography; longitudinal strain imaging, diastolic functional parameters, (123)I-MIBG, (111)In-Antimyosin antibody imaging, and (99m)Tc-Annexin V apoptosis imaging, biomarkers including troponins and BNP; genetic markers, and both functional and tissue characterization techniques with T1 weighted and T2 weighted images with cardiac magnetic resonance imaging (CMR). In our quest to optimize strategies for long-term cancer survival and prevention of CHF for patients receiving chemotherapy, rigorous modality and guideline-specific clinical outcome trials are required. A new multi-modality monitoring approach is proposed, which integrates evidence-based strengths of CMR, echocardiography, ERNA, biomarkers, and BP management for surveillance and validation of cardiotoxicity and prevention of clinical heart failure in patients receiving a broad spectrum of cancer therapies.

Cardiac imaging approaches to evaluate drug-induced myocardial dysfunction

The ability to make informed benefit-risk assessments for potentially cardiotoxic new compounds is of considerable interest and importance at the public health, drug development, and individual patient levels. Cardiac imaging approaches in the evaluation of drug-induced myocardial dysfunction will likely play an increasing role. However, the optimal choice of myocardial imaging modality and the recommended frequency of monitoring are undefined. These decisions are complicated by the array of imaging techniques, which have varying sensitivities, specificities, availabilities, local expertise, safety, and costs, and by the variable time-course of tissue damage, functional myocardial depression, or recovery of function. This White Paper summarizes scientific discussions of members of the Cardiac Safety Research Consortium on the main factors to consider when selecting nonclinical and clinical cardiac function imaging techniques in drug development. We focus on 3 commonly used imaging modalities in the evaluation of cardiac function: echocardiography, magnetic resonance imaging, and radionuclide (nuclear) imaging and highlight areas for future research.

Enhanced myocardial fluorodeoxyglucose uptake following Adriamycin-based therapy: Evidence of early chemotherapeutic cardiotoxicity?

AIM: To analyze changes in myocardial glucose metabolism using fluorodeoxyglucose (FDG)-positron emission tomography (PET) in patients treated with adriamycin and to investigate the clinical significance of these changes.

METHODS: Considering that FDG-PET scanning has the ability to show changes in glucose metabolism in the myocardium, we retrospectively analyzed the FDG-PET studies of 18 lymphoma patients treated with adriamycin-based chemotherapy in both the pre- and post-therapy setting. Cardiac contractile parameters such as left ventricular ejection fraction were not available for correlation in all patients due to the short duration and the level of cumulative dose administered in these patients during the time of the follow-up FDG-PET study. The change in myocardial glucose utilization was estimated by change in standard uptake values (SUV) in the myocardium.

RESULTS: We observed a significant change in SUVmean values in the myocardium (defined as more than ± 20% change in cardiac SUVmean between pre- and post-chemotherapy PET) in 12 patients, whereas 6 patients did not show any significant cardiac FDG uptake in both pre- and post-therapy PET scans. Patients were divided into three groups based on the changes observed in myocardial tracer uptake on the follow-up ¹⁸F-FDG-PET study. Group A (n = 8): showed an increase in cardiac ¹⁸F-FDG uptake in the post-therapy scan compared to the baseline scan carried out prior to starting adriamycin-based chemotherapy. Group B (n = 6): showed no significant cardiac ¹⁸F-FDG uptake in post-therapy and baseline PET scans, and group C (n = 4): showed a fall in cardiac ¹⁸F-FDG uptake in the post-therapy scan compared to the baseline scan. Mean cumulative adriamycin dose (in mg/m²) received during the time of the follow-up FDG-PET study was 256.25, 250 and 137.5, respectively.

CONCLUSION: Our study shows three different trends in the change in myocardial glucose metabolism in patients undergoing adriamycin-based chemotherapy. A further prospective study with prolonged follow-up of ventricular function is warranted to explore the significance of enhanced FDG uptake as a marker of early identification of adriamycin-induced cardiotoxicity.

Scintigraphic techniques for early detection of cancer treatment-induced cardiotoxicity

New antitumor agents have resulted in significant survival benefits for cancer patients. However, several agents may have serious cardiovascular side effects. Left ventricular ejection fraction measurement by (99m)Tc multigated radionuclide angiography is regarded as the gold standard to measure cardiotoxicity in adult patients. It identifies left ventricular dysfunction with high reproducibility and low interobserver variability. A decrease in left ventricular ejection fraction, however, is a relatively late manifestation of myocardial damage. Nuclear cardiologic techniques that visualize pathophysiologic processes at the tissue level could detect myocardial injury at an earlier stage. These techniques may give the opportunity for timely intervention to prevent further damage and could provide insights into the mechanisms and pathophysiology of cardiotoxicity caused by anticancer agents. This review provides an overview of past, current, and promising newly developed radiopharmaceuticals and describes the role and recent advances of scintigraphic techniques to measure cardiotoxicity. Both first-order functional imaging techniques (visualizing mechanical [pump] function), such as (99m)Tc multigated radionuclide angiography and (99m)Tc gated blood-pool SPECT, and third-order functional imaging techniques (visualizing pathophysiologic and neurophysiologic processes at the tissue level) are discussed. Third-order functional imaging techniques comprise (123)I-metaiodobenzylguanidine scintigraphy, which images the efferent sympathetic nervous innervations; sympathetic neuronal PET, with its wide range of tracers; (111)In-antimyosin, which is a specific marker for myocardial cell injury and necrosis; (99m)Tc-annexin V scintigraphy, which visualizes apoptosis and cell death; fatty-acid-use scintigraphy, which visualizes the storage of free fatty acids in the lipid pool of the cytosol (which can be impaired by cardiotoxic agents); and (111)In-trastuzumab imaging, to study trastuzumab targeting to the myocardium. To define the prognostic importance and clinical value of each of these functional imaging techniques, prospective clinical trials are warranted.

Alterations of pre- and postsynaptic noradrenergic signaling in a rat model of adriamycin-induced cardiotoxicity

BACKGROUND

Altered sympathetic nervous system signaling is known to play a role in the cardiotoxicity of the anthracycline chemotherapeutic agents, but the interaction of pre- and postsynaptic function is not well understood.

METHODS AND RESULTS

Our aim was to study the noradrenergic signaling in an established rat model of adriamycin cardiotoxicity (15 mg/kg administered i.p. over 2 weeks) using radiotracers having potential applicability for imaging with positron emission tomography (PET). Ex vivo biodistribution was performed 1 and 3 weeks post-adriamycin treatment with the noradrenaline analogue [(11)C]meta-hydroxyephedrine ([(11)C]HED), beta-adrenergic receptor antagonist [(3)H]CGP12177, and phosphodiesterase-4 inhibitor (R)-[(11)C]rolipram. Cardiac function (echocardiographic parameters) and heart/body weight ratio were not affected. Myocardial retention of [(11)C]HED, [(3)H]CGP12177, and (R)-[(11)C]rolipram were unchanged 1 week post-adriamycin. Compared to controls, 3 weeks post-treatment [(3)H]CGP12177 uptake decreased (left ventricle free wall and septum; P < 0.05), while [(11)C]HED and (R)-[(11)C]rolipram uptake were unaffected. Following acute increase in myocardial noradrenaline levels with desipramine treatment, (R)-[(11)C]rolipram retention increased in the left atrium, right ventricle, left ventricle free wall and septum (P < 0.05) in vehicle-, but not adriamycin-treated animals.

CONCLUSION

Our results suggest that adriamycin-induced toxicity exhibits no change in presynaptic noradrenaline uptake, but decreased beta-adrenergic receptors in cardiac tissues, supporting a role for PET imaging of noradrenaline signaling in the study of anthracycline cardiotoxicity.

B-type natriuretic peptide as a marker of subclinical heart injury during mitoxantrone therapy in MS patients--preliminary study

The aim of this study was to evaluate the plasma level changes of B-type natriuretic peptide (BNP), biochemical marker of heart failure, and echocardiographic parameters during mitoxantrone treatment in 22 multiple sclerosis (MS) patients (8 males, 14 females, mean age 37.1+/-6.6). Mitoxantrone (after mean cumulative dose of 58.0+/-7.0 mg/m(2)) did not alter left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), posterior wall thickness (PWT) and left ventricular end-diastolic volume (LVEDV). However, mean plasma level of BNP raised from 14.53+/-3.29 pg/ml at the baseline to 16.79+/-3.05 pg/ml and 18.83+/-4.90 pg/ml (P<0.01) after mean mitoxantrone dose of 30.7+/-5.9 mg/m(2) and 58.0+/-7.0 mg/m(2), respectively. These results strongly suggest subclinical myocardial dysfunction in mitoxantrone-treated group. We assume, that low-cost, repeated BNP measurements may be a good alternative for detection of early subtle myocardial injury in MS patients during routine mitoxantrone therapy.

Doxorubicin generates a proapoptotic phenotype by phosphorylation of elongation factor 2

We have previously shown that doxorubicin sensitizes prostate cancer cells to tumor-necrosis-factor-related apoptosis-inducing ligand (TRAIL). Sensitization correlated with decreased expression of the antiapoptotic cellular FLICE-like inhibitor protein (cFLIP(S)). The decrease in cFLIP(S) could not be explained by transcriptional regulation or increased degradation, leading us to focus on translational mechanisms. In this study, we found that doxorubicin caused strong and sustained phosphorylation of elongation factor 2 (EF-2), which interferes with protein elongation. Phosphorylation of EF-2 appeared to occur in a kinase-independent manner. Treatment with hydrogen peroxide recapitulated the events observed after doxorubicin treatment. In addition, cells treated with hydrogen peroxide expressed less X-linked inhibitor of apoptosis protein (XIAP) and survivin which, like cFLIP(S), are short-half-life proteins with an antiapoptotic function while expression levels of DR5, caspases-8, -9, -3, and Bax are maintained. The doxorubicin-mediated decrease in cFLIP(S) and XIAP and the TRAIL-induced apoptosis were prevented by pretreatment with an iron chelator, indicating that expression of these proteins was affected by free radical generation upon interaction of iron with doxorubicin. In conclusion, our data suggest that free radicals can affect the phosphorylation of EF-2 resulting in a net loss of short-half-life proteins such as cFLIP(S) and XIAP, leaving a cell more vulnerable to apoptotic stimuli.

Right ventricular parameters: prospect for routine assessment by equilibrium radionuclide angiographic SPECT

While left ventricular (LV) function is assessed routinely for heart disease, right ventricular (RV) assessment has attracted relatively little attention due to technical difficulties, even though RV function plays an important role in determining prognosis. This issue of the Communications includes a report that a SPECT ERNA algorithm applied to data for patients with tetralogy of Fallot exhibited RV dysfunction compared to normal subjects, as reported previously using different ERNA SPECT algorithms. That ERNA SPECT methods appear to produce results that are expected of patient group who should exhibit RV abnormalities presents the prospect that such algorithms also could be used to evaluate whether patients undergoing chemotherapy with anthracyclines and other cardiotoxic chemotherapeutic agents become at risk of developing RV, as well as, LV dysfunction. SPECT ERNA may well become the standard test for monitoring RV and LV components of heart disease in managing patients undergoing chemotherapy.