Monitoring Cardiac Function in Patients Receiving Doxorubicin

Interleukin-1β triggers muscle-derived extracellular superoxide dismutase expression and protects muscles from doxorubicin-induced atrophy

Doxorubicin, a conventional chemotherapeutic agent prescribed for cancer, causes skeletal muscle atrophy and adversely affects mobility and strength. Given that doxorubicin-induced muscle atrophy is attributable primarily to oxidative stress, its effects could be mitigated by antioxidant-focused therapies; however, these protective therapeutic targets remain ambiguous. The aim of this study was to demonstrate that doxorubicin triggers severe muscle atrophy via upregulation of oxidative stress (4-hydroxynonenal and malondialdehyde) and atrogenes (atrogin-1/MAFbx and muscle RING finger-1) in association with decreased expression of the antioxidant enzyme extracellular superoxide dismutase (EcSOD), in cultured C2C12 myotubes and mouse skeletal muscle. Supplementation with EcSOD recombinant protein elevated EcSOD levels on the cellular membrane of cultured myotubes, consequently inhibiting doxorubicin-induced oxidative stress and myotube atrophy. Furthermore, doxorubicin treatment reduced interleukin-1β (IL-1β) mRNA expression in cultured myotubes and skeletal muscle, whereas transient IL-1β treatment increased EcSOD protein expression on the myotube membrane. Notably, transient IL-1β treatment of cultured myotubes and local administration in mouse skeletal muscle attenuated doxorubicin-induced muscle atrophy, which was associated with increased EcSOD expression. Collectively, these findings reveal that the regulation of skeletal muscle EcSOD via maintenance of IL-1β signalling is a potential therapeutic approach to counteract the muscle atrophy mediated by doxorubicin and oxidative stress. KEY POINTS: Doxorubicin, a commonly prescribed chemotherapeutic agent for patients with cancer, induces severe muscle atrophy owing to increased expression of oxidative stress; however, protective therapeutic targets are poorly understood. Doxorubicin induced muscle atrophy owing to increased expression of oxidative stress and atrogenes in association with decreased protein expression of extracellular superoxide dismutase (EcSOD) in cultured C2C12 myotubes and mouse skeletal muscle. Supplementation with EcSOD recombinant protein increased EcSOD levels on the cellular membrane of cultured myotubes, resulting in inhibition of doxorubicin-induced oxidative stress and myotube atrophy. Doxorubicin treatment decreased interleukin-1β (IL-1β) expression in cultured myotubes and skeletal muscle, whereas transient IL-1β treatment in vivo and in vitro increased EcSOD protein expression and attenuated doxorubicin-induced muscle atrophy. These findings reveal that regulation of skeletal muscle EcSOD via maintenance of IL-1β signalling is a possible therapeutic approach for muscle atrophy mediated by doxorubicin and oxidative stress.

Lactate Can Modulate the Antineoplastic Effects of Doxorubicin and Relieve the Drug's Oxidative Damage on Cardiomyocytes

BACKGROUND

Doxorubicin (DOXO) is currently administered as the first-choice therapy for a variety of malignancies. Cancer cells exhibit enhanced glycolysis and lactate production. This metabolite affects gene expression and can play a role in chemoresistance.

AIM OF THIS STUDY

We investigated whether the enhanced lactate levels that characterize neoplastic tissues can modify the response of cancer cells to DOXO.

METHODS

After exposing cancer cells to increased lactate levels, we examined whether this metabolite could interfere with the principal mechanisms responsible for the DOXO antineoplastic effect.

RESULTS

Increased lactate levels did not affect DOXO-induced topoisomerase poisoning but offered protection against the oxidative damage caused by the drug. This protection was related to changes in gene expression caused by the combined action of DOXO and lactate. Oxidative damage significantly contributed to the heavy cardiotoxicity following DOXO treatment. In cultured cardiomyocytes, we confirmed that DOXO-induced DNA damage and oxidative stress can be significantly mitigated by exposing the cells to increased lactate levels.

CONCLUSIONS

In addition to contributing to elucidating the effects of the combined action of DOXO and lactate, our results suggest a possible method to reduce the heavy drug cardiotoxicity, a major side effect leading to therapy discontinuation.

Emerging role of PET/MR in the diagnosis and characterization of cardiotoxicity?

In cardiotoxicity, PET/MR affords an accurate evaluation of cardiovascular morphology, function, and also multi-parametric tissue characterization. A composite of several cardiac imaging parameters provided by the PET/MR scanner is likely to outperform a single parameter or imaging modality in the assessment and prediction of the severity and progression of cardiotoxicity but needing clinical investigations. Of particular interest, a heterogeneity map of single PET and CMR parameters could be perfectly correlated with the PET/MR scanner likely emerging as a promising marker of cardiotoxicity to monitor treatment response. While such functional and structural multiparametric imaging approach with cardiac PET/MR in the assessment and characterization of cardiotoxicity holds much promise, its validity and value in cancer patients treated with chemotherapy and/or radiation still needs to be assessed. The multi-parametric imaging approach with PET/MR, however, is likely to set new standards to develop predictive constellations of parameters for the severity and potential progression of cardiotoxicity that should afford timely and individualized treatment intervention to ascertain myocardial recovery and improved clinical outcome in these high-risk patients.

A Phase I, Open-Label, Dose-Escalation Study of the OX40 Agonist Ivuxolimab in Patients with Locally Advanced or Metastatic Cancers

PURPOSE

Stimulation of effector T cells is an appealing immunotherapeutic approach in oncology. OX40 (CD134) is a costimulatory receptor expressed on activated CD4⁺ and CD8⁺ T cells. Induction of OX40 following antigen recognition results in enhanced T-cell activation, proliferation, and survival, and OX40 targeting shows therapeutic efficacy in preclinical studies. We report the monotherapy dose-escalation portion of a multicenter, phase I trial (NCT02315066) of ivuxolimab (PF-04518600), a fully human immunoglobulin G2 agonistic monoclonal antibody specific for human OX40.

PATIENTS AND METHODS

Adult patients (N = 52) with selected locally advanced or metastatic cancers received ivuxolimab 0.01 to 10 mg/kg. Primary endpoints were safety and tolerability. Secondary/exploratory endpoints included preliminary assessment of antitumor activity and biomarker analyses.

RESULTS

The most common all-causality adverse events were fatigue (46.2%), nausea (28.8%), and decreased appetite (25.0%). Of 31 treatment-related adverse events, 30 (96.8%) were grade ≤2. No dose-limiting toxicities occurred. Ivuxolimab exposure increased in a dose-proportionate manner from 0.3 to 10 mg/kg. Full peripheral blood target engagement occurred at ≥0.3 mg/kg. Three (5.8%) patients achieved a partial response, and disease control was achieved in 56% of patients. Increased CD4⁺ central memory T-cell proliferation and activation, and clonal expansion of CD4⁺ and CD8⁺ T cells in peripheral blood were observed at 0.1 to 3.0 mg/kg. Increased immune cell infiltrate and OX40 expression were evident in on-treatment tumor biopsies.

CONCLUSIONS

Ivuxolimab was generally well tolerated with on-target immune activation at clinically relevant doses, showed preliminary antitumor activity, and may serve as a partner for combination studies.

PET Radiopharmaceuticals for Imaging Chemotherapy-Induced Cardiotoxicity

Purpose of Review

Currently, cardiotoxicity is monitored through echocardiography or multigated acquisition scanning and is defined as 10% or higher LVEF reduction. The latter stage may represent irreversible myocardium injury and limits modification of therapeutic paradigms at earliest stages. To stratify patients for anthracycline-related heart failure, highly sensitive and molecularly specific probes capable of interrogating cardiac damage at the subcellular levels have been sought.

Recent Findings

PET tracers may provide noninvasive assessment of earliest changes within myocardium. These tracers are at nascent stages of development and belong primarily to (a) mitochondrial potential-targeted and (b) general ROS (reactive oxygen species)-targeted radiotracers. Given that electrochemical gradient changes at the mitochondrial membrane represent an upstream, and earliest event before triggering the production of the ROS and caspase activity in a biochemical cascade, the former category might offer interrogation of cardiotoxicity at earliest stages exemplified by PET imaging, using ¹⁸F-Mitophos and ⁶⁸Ga-Galmydar in rodent models.

Summary

Both categories of radiotracers may provide tools for monitoring chemotherapy-induced cardiotoxicity and interrogating therapeutic efficacy of cardio-protectants.

Exercise stimulates beneficial adaptations to diminish doxorubicin-induced cellular toxicity

Doxorubicin (DOX) is a highly effective antitumor agent used for the treatment of a wide range of cancers. Unfortunately, DOX treatment results in cytotoxic side effects due to its accumulation within off-target tissues. DOX-induced cellular toxicity occurs as a result of increased oxidative damage, resulting in apoptosis and cell death. While there is no standard-of-care practice to prevent DOX-induced toxicity to healthy organs, exercise has been shown to prevent cellular dysfunction when combined with DOX chemotherapy. Endurance exercise stimulates numerous biochemical adaptations that promote a healthy phenotype in several vulnerable tissues without affecting the antineoplastic properties of DOX. Therefore, for the development of an effective strategy to combat the pathological effects of DOX, it is important to determine the appropriate exercise regimen to prescribe to cancer patients receiving DOX therapy and to understand the mechanisms responsible for exercise-induced protection against DOX toxicity to noncancer cells. This review summarizes the cytotoxic effects of DOX on the heart, skeletal muscle, liver, and kidneys and discusses the current understanding of the clinical benefits of regular physical activity and the potential mechanisms mediating the positive effects of exercise on each organ system.

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.

68Ga-Galmydar: A PET imaging tracer for noninvasive detection of Doxorubicin-induced cardiotoxicity

Background

Cancer patients undergoing Doxorubicin (DOX) treatment are susceptible to acute and chronic cardiac anomalies, including aberrant arrhythmias, ventricular dysfunction, and heart failure. To stratify patients at high risk for DOX -related heart failure (CHF), diagnostic techniques have been sought. While echocardiography is used for monitoring LVEF and LV volumes due to its wide-availability and cost-efficiency, it may not identify early stages of the initiation of DOX-induced systolic heart failure. To address these limitations, PET tracers could also provide noninvasive assessment of early and reversible metabolic changes of the myocardium.

Objective

Herein, we report a preliminary investigation of ⁶⁸Ga-Galmydar potential to monitor Dox-induced cardiomyopathy in vivo, ex vivo, and in cellulo employing both nuclear- and optical imaging.

Methods and results

To assess ⁶⁸Ga-Galmydar ability for monitoring DOX-induced cardiomyopathy, microPET imaging was performed 5 d post treatment of rats either with a single dose of DOX (15 mg/kg) or vehicle as a control (saline) and images were co-registered for anatomical reference using CT. Following tail-vein injection of the radiotracer in rats at 60 min, micro-PET/CT static scan (10 min acquisition), ⁶⁸Ga-Galmydar demonstrated 1.91-fold lower uptake in hearts of DOX-treated (standard uptake value; SUV: 0.92, n = 3) rats compared with their vehicle treated (SUV: 1.76, n = 3) control counterparts. For correlation of PET imaging data, post-imaging quantitative biodistribution studies were also performed, wherein excised organs were counted for γ activity, and normalized to injected dose. The post imaging pharmacokinetic data also demonstrated heart uptake values of 2.0 fold lower for DOX treated rats(%ID/g; DOX: 0.44 ± 0.1, n = 3) compared to their vehicle-treated controls (%ID/g; Control: 0.89 ± 0.03, n = 3, p = 0.04). Employing the fluorescent traits of Galmydar, live cell fluorescence imaging indicated a gradual decrease in uptake and retention of Galmydar within mitochondria of H9c2 cells following DOX-treatment, while indicating dose-dependent and time-dependent uptake profiles. Following depolarization of electronegative transmembrane gradients at the mitochondrial membrane, the uptake of the probe was decreased in H9c2 cells, and the uptake profiles were found to be identical, using both fluorescence and radiotracer bioassays. Finally, the decreased uptake of the metalloprobe in H9c2 cells also correlated with caspase-3 expression resulting from DOX-induced cardiotoxicity and cell death.

Conclusions

⁶⁸Ga-Galmydar could provide a noninvasive assessment of DOX-related and likely reversible metabolic changes at earliest stages. Further studies with other chemotherapeutics (potentially capable of inducing cardiomyopathy) are underway.

Mitochondrial accumulation of doxorubicin in cardiac and diaphragm muscle following exercise preconditioning

Doxorubicin (DOX) is a highly effective anthracycline antibiotic. Unfortunately, the clinical use of DOX is limited by the risk of deleterious effects to cardiac and respiratory (i.e. diaphragm) muscle, resulting from mitochondrial reactive oxygen species (ROS) production. In this regard, exercise is demonstrated to protect against DOX-induced myotoxicity and prevent mitochondrial dysfunction. However, the protective mechanisms are currently unclear. We hypothesized that exercise may induce protection by increasing the expression of mitochondria-specific ATP-binding cassette (ABC) transporters and reducing mitochondrial DOX accumulation. Our results confirm this finding and demonstrate that two weeks of exercise preconditioning is sufficient to prevent cardiorespiratory dysfunction.

BGP-15 Protects against Oxaliplatin-Induced Skeletal Myopathy and Mitochondrial Reactive Oxygen Species Production in Mice

Chemotherapy is a leading intervention against cancer. Albeit highly effective, chemotherapy has a multitude of deleterious side-effects including skeletal muscle wasting and fatigue, which considerably reduces patient quality of life and survivability. As such, a defense against chemotherapy-induced skeletal muscle dysfunction is required. Here we investigate the effects of oxaliplatin (OXA) treatment in mice on the skeletal muscle and mitochondria, and the capacity for the Poly ADP-ribose polymerase (PARP) inhibitor, BGP-15, to ameliorate any pathological side-effects induced by OXA. To do so, we investigated the effects of 2 weeks of OXA (3 mg/kg) treatment with and without BGP-15 (15 mg/kg). OXA induced a 15% (p < 0.05) reduction in lean tissue mass without significant changes in food consumption or energy expenditure. OXA treatment also altered the muscle architecture, increasing collagen deposition, neutral lipid and Ca²⁺ accumulation; all of which were ameliorated with BGP-15 adjunct therapy. Here, we are the first to show that OXA penetrates the mitochondria, and, as a possible consequence of this, increases mtROS production. These data correspond with reduced diameter of isolated FDB fibers and shift in the fiber size distribution frequency of TA to the left. There was a tendency for reduction in intramuscular protein content, albeit apparently not via Murf1 (atrophy)- or p62 (autophagy)- dependent pathways. BGP-15 adjunct therapy protected against increased ROS production and improved mitochondrial viability 4-fold and preserved fiber diameter and number. Our study highlights BGP-15 as a potential adjunct therapy to address chemotherapy-induced skeletal muscle and mitochondrial pathology.

Biomarkers for monitoring chemotherapy-induced cardiotoxicity

Cardiotoxicity, including acute and late-onset cardiotoxicity, is a well-known adverse effect of many types of antitumor agents. Early identification of patients with cardiotoxicity is important to ensure prompt treatment and minimize toxic effects. The etiology of chemotherapy-induced cardiotoxicity is multifactorial. Traditional methods for assessment of chemotherapy-induced cardiotoxicity typically involve serial measurements of cardiac function via multi-modality imaging techniques. Typically, however, significant left ventricular dysfunction has already occurred when cardiotoxicity is detected by imaging techniques. Biomarkers, most importantly cardiac natriuretic peptides and troponins, are promising markers for identifying patients potentially at risk for clinical heart failure symptoms. This review summarizes the recent progress in clinical utilization of biomarkers for early diagnosis of acute cardiotoxicity and for prediction of late-onset cardiotoxicity. We also discuss the conflicting results of different studies and the association of results with study design.

Effects of doxorubicin on cardiac muscle subsarcolemmal and intermyofibrillar mitochondria

Doxorubicin (DOX) is a highly effective chemotherapeutic used in the treatment of a broad spectrum of malignancies. However, clinical use of DOX is highly limited by cumulative and irreversible cardiomyopathy that occurs following DOX treatment. The pathogenesis of DOX-induced cardiac muscle dysfunction is complex. However, it has been proposed that the etiology of this myopathy is related to mitochondrial dysfunction, as a result of the dose-dependent increase in the mitochondrial accumulation of DOX. In this regard, cardiac muscle possesses two morphologically distinct populations of mitochondria. Subsarcolemmal (SS) mitochondria are localized just below the sarcolemma, whereas intermyofibrillar (IMF) mitochondria are found between myofibrils. Mitochondria in both regions exhibit subtle differences in biochemical properties, giving rise to differences in respiration, lipid composition, enzyme activities and protein synthesis rates. Based on the heterogeneity of SS and IMF mitochondria, we hypothesized that acute DOX administration would have distinct effects on each cardiac mitochondrial subfraction. Therefore, we isolated SS and IMF mitochondria from the hearts of female Sprague-Dawley rats 48h after administration of DOX. Our results demonstrate that while SS mitochondria appear to accumulate greater amounts of DOX, IMF mitochondria demonstrate a greater apoptotic and autophagic response to DOX exposure. Thus, the divergent protein composition and function of the SS and IMF cardiac mitochondria result in differential responses to DOX, with IMF mitochondria appearing more susceptible to damage after DOX treatment.

Mitochondria: Inadvertent targets in chemotherapy-induced skeletal muscle toxicity and wasting?

Chemotherapy has been associated with increased mitochondrial reactive oxygen species production, mitochondrial dysfunction and skeletal muscle atrophy leading to severe patient clinical complications including skeletal muscle fatigue, insulin resistance and wasting. The exact mechanisms behind this skeletal muscle toxicity are largely unknown, and as such co-therapies to attenuate chemotherapy-induced side effects are lacking. Here, we review the current literature describing the clinical manifestations and molecular origins of chemotherapy-induced myopathy with a focus on the mitochondria as the target organelle via which chemotherapeutic agents establish toxicity. We explore the likely mechanisms through which myopathy is induced, using the anthracycline doxorubicin, and the platinum-based alkylating agent oxaliplatin, as examples. Finally, we recommend directions for future research and outline the potential significance of these proposed directions.

Emerging delivery systems to reduce doxorubicin cardiotoxicity and improve therapeutic index: focus on liposomes

Anthracyclines are powerful anticancer agents and among the most important tools in the chemotherapy armamentarium of medical oncologists. They are approved for use in the treatment of a broad variety of solid and hematologic neoplasms. However, the usefulness of these agents, particularly doxorubicin, the most widely used anthracycline, is limited by considerable toxicity, especially damage to the cardiac muscle, which is cumulative and mostly irreversible, restricting extended use of this drug. In the last 30 years, extensive research with a variety of drug-delivery systems has attempted to overcome this limitation, with clinical success mostly confined to liposome formulations. Liposomal doxorubicin, and particularly pegylated liposomal doxorubicin, has shown significant pharmacologic advantages and an added clinical value over doxorubicin. Here, we review the mechanisms of action and toxicity of doxorubicin, and ways to reduce toxicity, with a focus on liposome-based drug-delivery systems.

Effects of short-term endurance exercise training on acute doxorubicin-induced FoxO transcription in cardiac and skeletal muscle

Doxorubicin (DOX) is a potent antitumor agent used in cancer treatment. Unfortunately, DOX can induce myopathy in both cardiac and skeletal muscle, which limits its clinical use. Importantly, exercise training has been shown to protect against DOX-mediated cardiac and skeletal muscle myopathy. However, the mechanisms responsible for this exercise-induced muscle protection remain elusive. These experiments tested the hypothesis that short-term exercise training protects against acute DOX-induced muscle toxicity, in part, due to decreased forkhead-box O (FoxO) transcription of atrophy genes. Rats (n = 6 per group) were assigned to sedentary or endurance exercise-trained groups and paired with either placebo or DOX treatment. Gene expression and protein abundance were measured in both cardiac and skeletal muscles to determine the impact of DOX and exercise on FoxO gene targets. Our data demonstrate that DOX administration amplified FoxO1 and FoxO3 mRNA expression and increased transcription of FoxO target genes [i.e., atrogin-1/muscle atrophy F-box (MaFbx), muscle ring finger-1 (MuRF-1), and BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3)] in heart and soleus muscles. Importantly, exercise training protected against DOX-induced increases of FoxO1 and MuRF-1 in cardiac muscle and also prevented the rise of FoxO3, MuRF-1, and BNIP3 in soleus muscle. Furthermore, our results indicate that exercise increased peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α) in both the heart and soleus muscles. This is important because increased PGC-1α expression is known to suppress FoxO activity resulting in reduced expression of FoxO target genes. Together, these results are consistent with the hypothesis that exercise training protects against DOX-induced myopathy in both heart (FoxO1 and MuRF-1) and skeletal muscles (FoxO3, MuRF-1, and BNIP3).

The combination of a low-dose chemotherapeutic agent, 5-fluorouracil, and an adenoviral tumor vaccine has a synergistic benefit on survival in a tumor model system

Standard cancer therapies, particularly those involving chemotherapy, are in need of modifications that both reduce short-term and long-term side effects as well as improve the overall survival of cancer patients. Here we show that combining low-dose chemotherapy with a therapeutic vaccination using an adenovirus encoding a model tumor-associated antigen, ovalbumin (Ad5-OVA), had a synergistic impact on survival in tumor-challenged mice. Mice that received the combinatorial treatment of Ad5-OVA plus low-dose 5-fluorouracil (5-FU) had a 95% survival rate compared to 7% and 30% survival rates for Ad5-OVA alone and 5-FU alone respectively. The presence of 5-FU enhanced the levels of OVA-specific CD8⁺ T lymphocytes in the spleens and draining lymph nodes of Ad5-OVA-treated mice, a phenomenon that was dependent on the mice having been tumor-challenged. Thus 5-FU may have enhanced survival of Ad5-OVA-treated mice by enhancing the tumor-specific immune response combined with eliminating tumor bulk. We also investigated the possibility that the observed therapeutic benefit may have been derived from the capacity of 5-FU to deplete MDSC populations. The findings presented here promote the concept of combining adenoviral cancer vaccines with low-dose chemotherapy.

Transcriptome profiling of peripheral blood cells identifies potential biomarkers for doxorubicin cardiotoxicity in a rat model

Aims

Doxorubicin (DOX), a widely used anticancer agent, can cause an unpredictable cardiac toxicity which remains a major limitation in cancer chemotherapy. There is a need for noninvasive, sensitive and specific biomarkers which will allow identifying patients at risk for DOX-induced cardiotoxicity to prevent permanent cardiac damage. The aim of this study was to investigate whether the expression of specific genes in the peripheral blood can be used as surrogate marker(s) for DOX-induced cardiotoxicity.

Methods/Results

Rats were treated with a single dose of DOX similar to one single dose that is often administered in humans. The cardiac and peripheral blood mononuclear cells (PBMCs) genome-wide expression profiling were examined using Illumina microarrays. The results showed 4,409 differentially regulated genes (DRG) in the hearts and 4,120 DRG in PBMC. Of these 2411 genes were similarly DRG (SDRG) in both the heart and PBMC. Pathway analysis of the three datasets of DRG using Gene Ontology (GO) enrichment analysis and Ingenuity Pathways Analysis (IPA) showed that most of the genes in these datasets fell into pathways related to oxidative stress response and protein ubiquination. IPA search for potential eligible biomarkers for cardiovascular disease within the SDRG list revealed 188 molecules.

Conclusions

We report the first in-depth comparison of DOX-induced global gene expression profiles of hearts and PBMCs. The high similarity between the gene expression profiles of the heart and PBMC induced by DOX indicates that the PBMC transcriptome may serve as a surrogate marker of DOX-induced cardiotoxicity. Future directions of this research will include analysis of PBMC expression profiles of cancer patients treated with DOX-based chemotherapy to identify the cardiotoxicity risk, predict DOX-treatment response and ultimately to allow individualized anti-cancer therapy.

Nanostructured lipid carriers: a potential drug carrier for cancer chemotherapy

Nanotechnology having developed exponentially, the aim has been on therapeutic undertaking, particularly for cancerous disease chemotherapy. Nanostructured lipid carriers have attracted expanding scientific and commercial vigilance in the last couple of years as alternate carriers for the pharmaceutical consignment, particularly anticancer pharmaceuticals. Shortcomings often came across with anticancer mixtures, such as poor solubility, normal tissue toxicity, poor specificity and steadiness, as well as the high incidence rate of pharmaceutical resistance and the rapid degradation, need of large-scale output procedures, a fast release of the pharmaceutical from its carrier scheme, steadiness troubles, the residues of the organic solvents utilized in the output method and the toxicity from the polymer with esteem to the carrier scheme are anticipated to be overcome through use of the Nanostructured Lipid Carrier. In this review the benefits, types, drug release modulations, steadiness and output techniques of NLCs are discussed. In supplement, the function of NLC in cancer chemotherapy is presented and hotspots in research are emphasized. It is foreseen that, in the beside future, nanostructured lipid carriers will be further advanced to consign cytotoxic anticancer compounds in a more efficient, exact and protected manner.

Equilibrium radionuclide angiocardiography: Its usefulness in current practice and potential future applications

The routine and potential future applications of equilibrium radionuclide angiocardiography/multigated acquisition (MUGA) in clinical decision making are explored in this review. The non-invasive nature of the test, less operator dependence, lower radiation dose and ease of performing, even in ill patients, are important considerations in clinical cardiology practice. Two important routine uses of this modality in day-to-day clinical practice include the following: serial assessment of left ventricular ejection fraction (LVEF) in patients receiving cardiotoxic chemotherapy, and determination of accurate LVEF in patients with intractable heart failure. Other potential utilities of MUGA that could be translated into clinical practice include determination of regional LVEF, obtaining information about both right and left ventricle in suitable patients as a part of first pass angiocardiography, identification of diastolic dysfunction in patients with heart failure with preserved LVEF, and demonstration of dyssynchrony prior to cardiac resynchronisation, specifically by MUGA single photon emission tomography.The last two indications are particularly important and evolving at this point.

Value of echocardiography and electrocardiography as screening tools prior to Doxorubicin administration

The dose-limiting toxicity of doxorubicin is cardiotoxicosis. The authors of this report hypothesized that by using their institution's adopted guidelines (that involve prescreening echocardiography and electrocardiography), they would detect pre-existing cardiac abnormalities that preclude doxorubicin administration in <10% of dogs. Of 101 dogs, only 6 were excluded from doxorubicin administration based on electrocardiogram abnormalities, with a majority of those arrhythmias classified as ventricular premature contractions. One patient was excluded based on echocardiogram alone due to hypertrophic cardiomyopathy. The incidence of cardiotoxicity in treated dogs was 8% (8/101). Additional pretreatment and ongoing studies are indicated to identify risk factors for cardiotoxicity.

Erythropoietin improves the healing of skin necrosis resulting from Doxorubicin extravasation in a rat model

BACKGROUND

Doxorubicin is an antineoplastic agent that causes skin necrosis when extravasated. Various agents have been tried to reduce tissue damage owing to extravasation. Erythropoietin (EPO) is an obligatory growth factor for red blood cells and has beneficial effects on wound healing.

OBJECTIVE

The aim of this study was to test the hypothesis that local EPO injection can prevent and improve healing of necrosis at the doxorubicin injection site in rats.

METHODS

We used 31 female Sprague-Dawley rats. The dorsal area of each rat was shaved, and 2 mg of doxorubicin in 0.5 mL saline was injected intradermally. The rats were then divided into 3 groups: control; control with intradermal injection of saline; and treatment, which received an intradermal injection of EPO. EPO in saline was injected into 4 quadrants of the same site where doxorubicin was injected 1 hour before. The rats were monitored and the area of each ulcer was measured. Skin biopsies were excised at the end of 4 weeks using anesthetic pentobarbital. Inflammation, edema, epithelization, neovascularization, necrosis, fibroblast proliferation, and collagen synthesis were evaluated and compared between groups.

RESULTS

The average areas of the lesions were significantly smaller in the EPO-injected rats (P = 0.03). The histopathologic evaluation revealed that the scores for epithelization, neovascularization, fibroblast proliferation, and collagen synthesis were higher (P < 0.001, P < 0.001, P = 0.002, and P = 0.04, respectively) and the score for necrosis was lower (P < 0.001) in the EPO-injected group than in both the saline-injected and control groups.

CONCLUSIONS

In this study using female Sprague-Dawley rats, EPO treatment improved the healing of skin necrosis caused by doxorubicin injection. This finding may lead to a new therapeutic approach for the management of skin necrosis caused by doxorubicin extravasation.

Increased efficacy of doxorubicin delivered in multifunctional microparticles for mesothelioma therapy

New and effective treatment strategies are desperately needed for malignant mesothelioma (MM), an aggressive cancer with a poor prognosis. We have shown previously that acid-prepared mesoporous microspheres (APMS) are nontoxic after intrapleural or intraperitoneal (IP) administration to rodents. The purpose here was to evaluate the utility of APMS in delivering chemotherapeutic drugs to human MM cells in vitro and in two mouse xenograft models of MM. Uptake and release of doxorubicin (DOX) alone or loaded in APMS (APMS-DOX) were evaluated in MM cells. MM cell death and gene expression linked to DNA damage/repair were also measured in vitro. In two severe combined immunodeficient mouse xenograft models, mice received saline, APMS, DOX or APMS-DOX injected directly into subcutaneous (SC) MM tumors or injected IP after development of human MMs peritoneally. Other mice received DOX intravenously (IV) via tail vein injections. In comparison to DOX alone, APMS-DOX enhanced intracellular uptake of DOX, MM death and expression of GADD34 and TP73. In the SC MM model, 3× weekly SC injections of APMS-DOX or DOX alone significantly inhibited tumor volumes, and systemic DOX administration was lethal. In mice developing IP MMs, significant (p < 0.05) inhibition of mesenteric tumor numbers, weight and volume was achieved using IP administration of APMS-DOX at one-third the DOX concentration required after IP injections of DOX alone. These results suggest APMS are efficacious for the localized delivery of lower effective DOX concentrations in MM and represent a novel means of treating intracavitary tumors.

Short-term exercise training protects against doxorubicin-induced cardiac mitochondrial damage independent of HSP72

Doxorubicin (Dox) is an antitumor agent used in cancer treatment, but its clinical use is limited due to cardiotoxicity. Although exercise training can defend against Dox-mediated cardiac damage, the means for this cardioprotection remain unknown. To investigate the mechanism(s) responsible for exercise training-induced cardioprotection against Dox-mediated cardiotoxicity, we tested a two-pronged hypothesis: 1) exercise training protects against Dox-induced cardiotoxicity by preventing Dox-mediated mitochondrial damage/dysfunction and increased oxidative stress and 2) exercise training-induced cardiac expression of the inducible isoform of the 70-kDa heat shock protein 72 (HSP72) is essential to achieve exercise training-induced cardioprotection against Dox toxicity. Animals were randomly assigned to sedentary or exercise groups and paired with either placebo or Dox treatment (i.e., 20 mg/kg body wt ip Dox hydrochloride 24 h before euthanasia). Dox administration resulted in cardiac mitochondrial dysfunction, activation of proteases, and apoptosis. Exercise training increased cardiac antioxidant enzymes and HSP72 protein abundance and protected cardiac myocytes against Dox-induced mitochondrial damage, protease activation, and apoptosis. To determine whether exercise-induced expression of HSP72 in the heart is required for this cardioprotection, we utilized an innovative experimental strategy that successfully prevented exercise-induced increases in myocardial HSP72 levels. However, prevention of exercise-induced increases in myocardial HSP72 did not eliminate the exercise-induced cardioprotective phenotype that is resistant to Dox-mediated injury. Our results indicate that exercise training protects against the detrimental side effects of Dox in cardiac myocytes, in part, by protecting mitochondria against Dox-mediated damage. However, this exercise-induced cardioprotection is independent of myocardial HSP72 levels. Finally, our data are consistent with the concept that increases in cardiac mitochondrial antioxidant enzymes may contribute to exercise-induced cardioprotection.

Monotherapy with anti-CD20 monoclonal antibody in a heart transplant recipient with sick sinus syndrome and posttransplantation lymphoproliferative disorder: a case report

Posttransplantation lymphoproliferative disorder (PTLD) is a serious complication of organ transplantation, with an incidence of 0.8% to 20% in heart transplant (HTx) recipients, and standard treatment may be too toxic in some cases. Rituximab is an anti-CD20 monoclonal antibody that has demonstrated efficacy in patients with various lymphoid malignancies and has been demonstrated effective in combination with chemotherapy regimens such as CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone). Cardiotoxicity with CHOP remains a major concern for treating HTx recipients with PTLD, however. We present a case of an HTx recipient with sick sinus syndrome and PTLD who was successfully treated with rituximab alone, avoiding the cardiotoxicity of CHOP. The cardiotoxicity induced by CHOP should be kept in mind in HTx recipients with PTLD, especially when there is an existing heart problem in such recipients. Monotherapy with rituximab can be considered a safe choice.

Effects of dexrazoxane and amifostine on evolution of Doxorubicin cardiomyopathy in vivo

Doxorubicin is one of the most active drugs in oncology, with cardiotoxicity as a serious side effect of its application. The aim of this study was to investigate dexrazoxane and amifostine impact on the evolution of myocardial changes induced by doxorubicin. BalbC female mice were treated with doxorubicin only (10 mg/kg, single intravenous push), or with dexrazoxane (200 mg/kg, intraperitoneal [ip]) or amifostine (200 mg/kg, ip) 60 mins or 30 mins prior to treatment with doxorubicin, respectively. Blood sampling for determination of conventional serum-marker activity was performed 48 hrs later. The grade of histopathology changes was evaluated by light microscopy 1.5 and 3 months after treatments using the Billingham scoring method. Control groups consisted of nontreated mice. After doxorubicin-only treatment, the grade of heart tissue damage was found to increase in the period between 1.5 and 3 months. A similar but less intense progression was also detected in amifostine-pretreated animals, with significant difference among median Billingham scores between the two time points. The pretreatment with dexrazoxane suspended expansion of tissue lesions in time. Changes in serum enzyme activity revealed two correlations: the greater reduction in alpha-hydroxybutyrate dehydrogenase (alpha-HBDH) leakage is associated with a lower percentage of damaged tissue, and the creatine kinase to alpha-HBDH percent of difference ratio being greater than one is correlated with limited spreading of pathological lesions. Our results indicate that the development of doxorubicin-induced heart failure is based on a slow and persistent expansion of pathological process even long after the completion of the treatment. Dexrazoxane has proved to be successful and superior over amifostine against such an evolution of doxorubicin cardiomyopathy.

Limited cardiotoxicity after extensive thoracic surgery and intraoperative hyperthermic intrathoracic chemotherapy with doxorubicin and cisplatin

BACKGROUND

Recently, pleural mesothelioma has been treated by cytoreductive surgery and intraoperative hyperthermic intrathoracic chemotherapy with doxorubicin and cisplatin. The well-established cardiotoxicity of doxorubicin and distressing data from an animal study raised concern about its impact on cardiac function. In the present study, early cardiotoxicity of this treatment modality was prospectively analyzed.

PATIENTS AND METHODS

In 13 pleural mesothelioma patients, cardiotoxicity was monitored by clinical examination, electrocardiography, Troponin levels, cardiac ultrasonography, and estimation of left ventricular ejection fraction (LVEF) by radionuclide ventriculography before and during the first 6 months after cytoreductive surgery and intraoperative hyperthermic intrathoracic chemotherapy with doxorubicin (25-54 mg/m(2)) and cisplatin (65-120 mg/m(2)).

RESULTS

No clinical cardiac failure or treatment-related death was observed. In two patients transient atrial fibrillation was noted; one associated with pulmonary emboli. Early posttreatment Troponin release was not of predictive value. Ultrasonography did not reveal significant alterations. LVEF decreased significantly (mean 0.07 or 11%, P = .001) during the first 3 months and remained stable thereafter. In univariate analysis, the degree of LVEF reduction was statistically related to maximal intrathoracic doxorubicin concentration (P = .031) and total cisplatin dose (P = .029). Direct exposure of the heart to the drugs as a result of partial pericardectomy was not associated with greater LVEF decrease. On the contrary, partial pericardectomy seemed to be associated with a smaller LVEF decline than when the pericardium remained intact (P = .045). In this small series, no statistically significant correlation between other treatment or pharmacokinetic parameters and LVEF decline was found. Notably, higher doxorubicin plasma concentrations and exposure were not associated with increased LVEF reduction.

CONCLUSIONS

Early cardiotoxicity is limited after this treatment modality using substantial doses of doxorubicin and cisplatin. Hence, this study suggests that intrathoracic chemotherapy with doxorubicin and/or cisplatin may be used for primary and secondary pleural malignancies, even immediately after extensive thoracic surgery, without concern of severe early cardiotoxicity.

Adriamycin-induced myocardial toxicity: New solutions for an old problem?

Adriamycin is a potent and broad-spectrum antineoplastic agent that plays a major role in cancer chemotherapy. Unfortunately, its use has been hampered by conventional toxicities and cardiotoxicity manifested by congestive cardiomyopathy. Adriamycin is particularly toxic to heart tissue and constitutes a major cause of morbidity and mortality due to its complex pathogenesis. In this review, the different forms of cardiotoxicity produced by adriamycin as well as the biochemical changes induced by this drug are summarized. Secondly, the current hypotheses proposed to explain adriamycin-induced myocardial damage (the iron and free-radical hypothesis, the metabolic hypothesis, the "unifying hypothesis" and apoptosis) and the attempts to reduce adriamycin-induced myocardial toxicity are discussed (e.g. dose limitation, close cardiac monitoring, alteration of dosage schedules, development of new anthracycline analogs, and the administration of protective agents and liposomal encapsulation). Finally, we summarized our own experimental and clinical experience in ameliorating and or preventing adriamycin-induced cardiotoxicity and the latest attempts to prevent and/or monitor cardiac function. According to this, a combination of usual doses of calcium antagonist drugs plus vitamins A and E seems advisable.