Evaluation of cardiac troponin I and T levels as markers of myocardial damage in doxorubicin-induced cardiomyopathy rats, and their relationship with echocardiographic and histological findings

Zinc's protective role against hydroxychloroquine-induced cardiac effects in adult male albino rats

Background

Long exposure to Hydroxychloroquine (HCQ) has been complicated by some dangerous though infrequent cardiotoxicity.

Methods

A total of 40 normal adult male albino rats dispersed into 4 groups were used. Group 1 (Control group), Group II (HCQ treated group), Group III (zinc [Zn]-treated group), and Group IV (HCQ and Zn treated group). Once the experimentation ended, rats were sacrificed and cardiac soft tissue sections were processed twenty-four hours at the end of the experiment for histological study.

Results

Cardiac-stained sections revealed that HCQ induced widespread necrosis, dilatation, and vacuolar degeneration. However, the combination of HCQ with Zn ameliorated these damaging effects. Cardiac enzyme parameters were also studied in the 4 groups and revealed CK-MB and troponin were considerably elevated in groups II associated to the control group.

Conclusion

It was concluded that Zn revealed a protective role against HCQ cardiomyopathy in adult male albino rats. This might signify an appreciated means for Zn-based treatment in the upcoming subsequent clinical records to adjust doses and guarantee patient safeguard.

Melatonin Attenuates Extracellular Matrix Accumulation and Cardiac Injury Manifested by Copper

Copper-induced cardiac injury is not widely reported in spite of its ability to cause oxidative damage and tissue injury. Structural and morphological changes in the cardiac tissue are triggered via oxidative stress and inflammatory responses following copper exposure. The varied and unavoidable exposure of copper through contaminated food and water warrants a safe and effective agent against its harmful effects. Since the heart is highly sensitive to changes in the redox balance, the present study was undertaken to examine the protective effects of melatonin against copper-induced cardiac injury. Sprague Dawley (SD) rats were exposed to 100 ppm of elemental copper via drinking water for 4 months. The cardiac tissue was evaluated for various biochemical, histological, and protein expression studies. Animals exposed to copper exhibited induced oxidative stress and cardiac injury compared to normal control. To this end, we found that melatonin treatment ameliorated copper-induced alterations in tissue oxidative variables like ROS, nitrate, MDA, and GSH. In addition, histological examinations unravelled decreased cardiac muscle dilation, atrophy, and cardiomyopathy in melatonin-treated rats. Furthermore, melatonin-treated rats were associated with reduced tissue copper levels, collagen deposition, α-SMA, and increased HO-1 expression as compared to rats exposed exclusively to copper. Moreover, the levels of NF-κB and cardiac markers such as CK-MB, cTnI, and cTnT were found to be decreased in the melatonin-treated animals. Altogether, melatonin-triggered increase in antioxidant capacity resulting in reduced aggregation of ECM components demonstrates the therapeutic potential of melatonin in the treatment of cardiac injury and tissue fibrosis.

Theranostic Applications of an Ultra-Sensitive T1 and T2 Magnetic Resonance Contrast Agent Based on Cobalt Ferrite Spinel Nanoparticles

Nano-dimensional materials have become a focus of multiple clinical applications due to their unique physicochemical properties. Magnetic nanoparticles represent an important class of nanomaterials that are widely studied for use as magnetic resonance (MR) contrast and drug delivery agents, especially as they can be detected and manipulated remotely. Using magnetic cobalt ferrite spinel (MCFS) nanoparticles, this study was aimed at developing a multifunctional drug delivery platform with MRI capability for use in cancer treatment. We found that MCFS nanoparticles demonstrated outstanding properties for contrast MRI (r₁ = 22.1 s^-1mM^-1 and r₂ = 499 s^-1mM^-1) that enabled high-resolution T₁- and T₂-weighted MRI-based signal detection. Furthermore, MCFS nanoparticles were used for the development of a multifunctional targeted drug delivery platform for cancer treatment that is concurrently empowered with the MR contrast properties. Their therapeutic effect in systemic chemotherapy and unique MRI double-contrast properties were confirmed in vivo using a breast cancer mouse tumor model. Our study thus provides an empirical basis for the development of a novel multimodal composite drug delivery system for anticancer therapy combined with noninvasive MRI capability.

Ultrasmall Nanoparticle Delivery of Doxorubicin Improves Therapeutic Index for High-Grade Glioma

Purpose: Despite dramatic growth in the number of small molecule drugs developed to treat solid tumors, durable therapeutic options to control primary central nervous system malignancies are relatively scarce. Chemotherapeutic agents which appear biologically potent in model systems have often been found to be marginally effective at best when given systemically in clinical trials. This work presents for the first time an ultrasmall (< 8 nm) multimodal core-shell silica nanoparticle, Cornell prime dots (or C' dots), for the efficacious treatment of high-grade gliomas. Experimental Design: This work presents first-in-kind renally-clearable ultrasmall (< 8 nm) multimodal Cornell prime dots (or C' dots) with surface-conjugated doxorubicin via pH-sensitive linkers for the efficacious treatment in two different clinically relevant high-grade glioma models. Results: Optimal drug-per-particle ratios of as-developed nanoparticle-drug conjugates were established and used to obtain favorable pharmacokinetic profiles. The in vivo efficacy results showed significantly improved biological, therapeutic, and toxicological properties over the native drug after intravenous administration in platelet-derived growth factor-driven genetically engineered mouse model, and an epidermal growth factor expressing patient-derived xenograft (EGFR PDX) model. Conclusions: Ultrasmall C' dot-drug conjugates showed great translational potential over doxorubicin for improving the therapeutic outcome of patients with high-grade gliomas, even without a cancer-targeting moiety.

Cardio-protective effects of Terminalia catappa leaves and Terminalia chebula fruit extract in doxorubicin-induced cardiomyopathy in rats

INTRODUCTION

The cardio-protective effects of Terminalia catappa and Terminalia chebula are well-recognized in Ayurveda for its antimicrobial, antidiabetic and antioxidant potentials. The present study evaluates the effects of T. catappa leaves (Tct.LE) and T. chebula fruits (Tce.FE) against doxorubicin (DOX)-induced rats through analysis of the cardiac biomarkers, tricarboxylic acid (TCA) cycle enzymes and respiratory chain enzymes for their cardio-protective properties. Materials and methods: This study includes 42 adult male Albino Wistar rats randomized into seven groups for 21-days. Groups were categorized as control; DOX (1.5 mg/kg) induced negative control; basal diet with 300 mg/kg of Tct.LE, with 300 mg/kg Tce.FE; DOX with 300 mg/kg of Tct.LE, Tce.FE, and propranolol (25mg/kg). Results and Discussion: The doses of 300 mg/kg of both plants have a significant effect on the TCA cycle, respiratory and lysosomal enzymes activity. The troponin levels are significantly reduced in plant treated group than the DOX-treated rats when compared with the control and propranolol treated group. Likewise, the increased level of creatine kinase-muscle/MB, creatine kinase and lipid profile in the DOX-treated animals were significantly reduced upon being treated with extracts. Conclusion: The cardio-protective activity of Tct.LE leaves and Tce.FE indicate its potential use in the management of cardiovascular diseases.

CLINICAL SIGNIFICANCE

The prevalence of cardiovascular disease is increasing day-by-day in this industrial world with leading cause of mortality and morbidity. Many researches are presently concentrated on the plant-based medicine due to its safety and free from side effects. Hence, the present study aims to document the potential cardio-protective benefits of Terminalia catappa and Terminalia chebula.

In Vivo Murine Models of Cardiotoxicity Due to Anticancer Drugs: Challenges and Opportunities for Clinical Translation

Modern therapeutic approaches have led to an improvement in the chances of surviving a diagnosis of cancer. However, this may come with side effects, with patients experiencing adverse cardiovascular events or exacerbation of underlying cardiovascular disease related to their cancer treatment. Rodent models of chemotherapy-induced cardiotoxicity are useful to define pathophysiological mechanisms of cardiac damage and to identify potential therapeutic targets. The key mechanisms involved in cardiotoxicity induced by specific different antineoplastic agents are summarized in this state-of-the-art review, as well as the rodent models of cardiotoxicity by different classes of anticancer drugs, along with the strategies tested for primary and secondary cardioprotection. Current approaches for early detection of cardiotoxicity in preclinical studies with a focus on the application of advanced imaging modalities and biomarker strategies are also discussed. Potential applications of cardiotoxicity modelling in rodents are illustrated in relation to the advancements of promising research topics of cardiotoxicity. Created with BioRender.com.

Paroxetine mitigates cardiac remodelling by doxorubicin and increases survival

Doxorubicin (DOX) is an effective anticancer drug. However, its use is hampered by the development of very mortal cardiomyopathy. Here, we investigate whether the co-administration of the antidepressant paroxetine (P), known to exert beneficial cardiovascular effects, would provide effective cardioprotection. Experiments were performed in male Wistar rats randomly assigned to control group (0.5 mL/kg 0.9% NaCl, i.v., n = 7), DOX group (DOX 5 mg /kg i.v., n = 23) and DOX+P group (DOX 5 mg/kg, i.v. plus P 10 mg/kg p.o. daily, beginning five days before DOX administration and during the follow-up period, n = 11). Rats' body weight and echocardiography parameters were monitored before and after drug/vehicle administration. Cardiac histology was performed post-mortem, as well as beta1-adrenergic receptor (β₁-AR), beta2-adrenergic receptor (β₂-AR), G protein-coupled receptor kinases type 2 (GRK2), type 3 (GRK3), beta-arrestin 1, and beta-arrestin 2 gene expression using RT-qPCR. DOX-treated rats exhibited bad general condition, adynamia, loss of body weight, and low survival. Echocardiography revealed two phenotypes: cardiomyopathy with left ventricular (LV) hypertrophy (DOX-HCM) and cardiomyopathy with LV dilation (DOX-DCM). In DOX-HCM rats only, there was an increased GRK2 and GRK3 gene expression and synthesis. DOX+P co-treated rats exhibited good general condition, normal spontaneous behaviour, gained weight over time, had increased survival, and preserved LV morphology and contractility. In these rats, gene expression and synthesis of GRK2 and GRK3 were decreased, while β₁-AR and β₂-AR were increased. Present results show for the first time that P effectively reduces DOX-induced cardiotoxicity and enhances survival.

Protective Role of Vitamin B1 in Doxorubicin-Induced Cardiotoxicity in Rats: Focus on Hemodynamic, Redox, and Apoptotic Markers in Heart

Up until now, the specific mechanisms involved in doxorubicin (DOX)-induced cardiotoxicity have not been fully elucidated. Since thiamine deficiency is associated with myocardial dysfunction and it may lead to cardiomyopathy, we aimed to investigate whether thiamine (Vitamin B₁) treatment provides cardioprotection and modulates DOX mediated subchronic cardiotoxicity as well as to determine possible mechanisms of its effects. The study involved 48 Wistar albino rats divided into four groups: healthy non-treated rats and healthy rats treated with thiamine and DOX rats without treatment and DOX rats treated with thiamine. DOX was applied as a single i.p.injection (15mg/kg), while thiamine treatment lasted 7days (25mg/kg/dayi.p.). Before and after the treatment hemodynamic changes were monitored in vivo by echocardiography. When the protocol was completed, animals were sacrificed and rat hearts were isolated in order to evaluate parameters of cardiac oxidative stress [superoxide anion radical-O₂ ^-, hydrogen peroxide-H₂O₂, nitric oxide-NO^-, index of lipid peroxidation-thiobarbituric acid (TBA) reactive substances (TBARS), superoxide dismutase - SOD, catalase (CAT), and reduced glutathione-GSH] and apoptosis (Bax, Bcl-2, caspases). DOX treatment significantly reduced the ejection fraction, while thiamine treatment led to its minor increase in the DOX-treated group. In that sense, heart oxidative stress markers were significantly increased in DOX-treated rats, while therapeutic dose of thiamine decreased the levels of free radicals. Our study demonstrated the promising ameliorative effects of thiamine against DOX-induced cardiotoxicity through modulation of oxidative stress, suppression of apoptosis, and possibility to improve myocardial performance and morphometric structure of rats` hearts.

Acute and Delayed Doxorubicin-Induced Myocardiotoxicity Associated with Elevation of Cardiac Biomarkers, Depletion of Cellular Antioxidant Enzymes, and Several Histopathological and Ultrastructural Changes

Doxorubicin (DOX; Adricin) is an anthracycline antibiotic, which is an efficient anticancer chemotherapeutic agent that targets many types of adult and pediatric tumors, such as breast cancer, leukemia, and lymphomas. However, use of DOX is limited due to its cardiotoxic effects. This study sequentially investigated the mechanistic pathways of the cardiotoxic process of DOX in rats at different post-treatment periods using cumulative dose, which is used in therapeutic regimes. In this regard, 56 male albino rats were used for the experiment. The experimental animals were divided into seven groups (n = 8/group) based on dose and sacrifice schedule as follows: G1 (2 mg/kg body weight [BW] and sacrificed at day 4), G2 (4 mg/kg BW and sacrificed at day 8), G3 (6 mg/kg BW and sacrificed at day 15), G4 (8 mg/kg BW and sacrificed at day 30), G5 (10 mg/kg BW and sacrificed at day 60), G6 (10 mg/kg BW and sacrificed at day 90), and G7 (10 mg/kg BW and sacrificed at day 120). As expected, G1, G2, and G3-treated groups revealed features of acute toxic myocarditis associated with degenerative and necrotic changes in myocytes, mitochondrial damage, elevation of cardiac biomarkers, and depletion of cellular antioxidant enzymes. However, these changes increased in severity with subsequent treatment with the same dose until reaching a cumulative dose of 10 mg/kg BW for 30 d. Furthermore, after a cumulative dose of 10 mg/kg BW with a withdrawal period of 2–3 months, various predominant changes in chronicity were reported, such as disorganization and atrophy of myocytes, condensation and atrophy of mitochondria, degranulation of mast cells, and fibrosis with occasional focal necrosis, indicating incomplete elimination of DOX and/or its metabolites. Altogether, these data provide interesting observations associated with the cardiotoxic process of DOX in rats that would help understand the accompanying changes underlying the major toxic effects of the drug. Future research is suggested to explore more about the dose-dependent mechanisms of such induced toxicity of DOX that would help determine the proper doses and understand the resulting cardiomyopathy.

Trehalose alleviates doxorubicin-induced cardiotoxicity in female Swiss albino mice by suppression of oxidative stress and autophagy

Clinically, the use of doxorubicin (DOX) is limited due to DOX-induced cardiotoxicity (DIC). The current study aimed to evaluate the cardioprotective effect of trehalose (TRE) against DIC in a female Swiss albino mouse model. Mice were divided into five experimental groups: Gp. I: saline control group (200 μl/mouse saline three times per week for 3 weeks day after day), Gp. II: DOX-treated group (2 mg/kg body weight three times per week for 3 weeks day after day), Gp. III: TRE group (200 μg/mouse three times per week for 3 weeks day after day), Gp. IV: DOX + TRE cotreatment group (animals were coadministered with DOX and TRE as in Gp. II and III, respectively), and Gp. V: DOX + TRE posttreatment group (animals were treated with DOX as in Gp. II followed by treatment with TRE as in Gp. III). DOX-treated mice showed significant elevation in cardiac injury biomarkers (lactate dehydrogenase, creatine kinase isoenzyme-MB, and cardiac troponin I), cardiac oxidative stress (OS) markers (malondialdehyde and myeloperoxidase), and cardiac levels of autophagy-related protein 5. Moreover, DOX significantly reduced the levels of total antioxidant capacity and activities of catalase and glutathione S-transferase. In contrast, TRE treatment of DOX-administered mice significantly improved almost all of the above-mentioned assessed parameters. Furthermore, histopathological changes of cardiac tissues observed in mice treated with TRE in combination with DOX were significantly improved as compared to DOX-treated animals. Taken together, the present study provides evidence that TRE has cardioprotective effects against DIC, which is likely mediated via suppression of OS and autophagy.

Biologics and their delivery systems: Trends in myocardial infarction

Cardiovascular disease is the leading cause of death around the world, in which myocardial infarction (MI) is a precipitating event. However, current therapies do not adequately address the multiple dysregulated systems following MI. Consequently, recent studies have developed novel biologic delivery systems to more effectively address these maladies. This review utilizes a scientometric summary of the recent literature to identify trends among biologic delivery systems designed to treat MI. Emphasis is placed on sustained or targeted release of biologics (e.g. growth factors, nucleic acids, stem cells, chemokines) from common delivery systems (e.g. microparticles, nanocarriers, injectable hydrogels, implantable patches). We also evaluate biologic delivery system trends in the entire regenerative medicine field to identify emerging approaches that may translate to the treatment of MI. Future developments include immune system targeting through soluble factor or chemokine delivery, and the development of advanced delivery systems that facilitate the synergistic delivery of biologics.

The mRNA expression of Il6 and Pdcd1 are predictive and protective factors for doxorubicin‑induced cardiotoxicity

Anthracyclines, such as doxorubicin (DOX), have been widely used in the treatment of a number of different solid and hematological malignancies. However, these drugs can inflict cumulative dose-dependent and irreversible damage to the heart, and can occasionally lead to heart failure. The cardiotoxic susceptibility varies among patients treated with anthracycline, and delays in the recognition of cardiotoxicity can result in poor prognoses. Accordingly, if the risk of cardiotoxicity could be predicted prior to drug administration, it would aid in safer and more effective chemotherapy treatment. The present study was carried out to identify genes that can predict DOX-induced cardiotoxicity (DICT). In an in vivo study, mice cumulatively treated with DOX demonstrated increases in serum levels of cardiac enzymes (aspartate aminotransferase, lactate dehydrogenase, creatine kinase MB isoenzyme and troponin T), in addition to decreases in body and heart weights. These changes were indicative of DICT, but the severity of these effects varied among individual mice. In the current study, the correlation in these mice between the extent of DICT and circulating blood concentrations of relevant transcripts before DOX administration was analyzed. Among various candidate genes, the plasma mRNA levels of the genes encoding interleukin 6 (Il6) and programmed cell death 1 (Pdcd1) in blood exhibited significant and positive correlations with the severity of DICT. In an in vitro study using cardiomyocyte H9c2 cells, knockdown of Il6 or Pdcd1 by small interfering RNA was revealed to enhance DOX-induced apoptosis, as determined by luminescent assays. These results suggested that the levels of transcription of Il6 and Pdcd1 in cardiomyocytes serve a protective role against DICT, and that the accumulation of these gene transcripts in blood is a predictive marker for DICT. To the best of our knowledge, this is the first report to demonstrate a role for Il6 and Pdcd1 mRNA expression in DICT.

Effects and mechanisms of glucose-insulin-potassium on post-procedural myocardial injury after percutaneous coronary intervention

OBJECTIVE

To evaluate the effects and mechanisms of glucose-insulin-potassium (GIK) on post-procedural myocardial injury (PMI) after percutaneous coronary intervention (PCI).

METHODS

A total of 200 non-diabetic patients with documented coronary heart disease (CHD) were divided into the Group GIK and Group G, with 100 patients in each group. Patients in Group G were given intravenous infusion of glucose solution 2 hours before PCI. As compared, patients in Group GIK were given GIK.

RESULTS

Both post-procedural creatine phosphokinase isoenzyme MB (CK-MB; 62.1 ± 47.8 vs. 48.8 ± 52.6 U/L, P = 0.007) and cTnI (0.68 ± 0.83 vs. 0.19 ± 0.24 ng/mL, P < 0.001) in Group GIK were significantly higher than those in Group G. In Group G, 9.0% and 4.0% of patients had post-procedural increases in CK-MB 1-3 times and > 3 times, which were significantly lower than those in Group GIK (14.0% and 7.0%, respectively; all P values < 0.01); 13.0% and 7.0% of patients had post-procedural increases in cTnI 1-3 times and > 3 times, which were also significantly lower than those in Group GIK (21.0% and 13.0%, respectively; all P < 0.001). Pre-procedural (10.2 ± 4.5 vs. 5.1 ± 6.3, P < 0.001) and post-procedural rapid blood glucose (RBG) levels (8.9 ± 3.9 vs. 5.3 ± 5.6, P < 0.001) in Group G were higher than those in Group GIK. In adjusted logistic models, usage of GIK (compared with glucose solution) remained significantly and independently associated with higher risk of post-procedural increases in both CK-MB and cTnI levels > 3 times. Furthermore, pre-procedural RBG levels < 5.0mmol/L were significantly associated with higher risk of post-procedural increases in both CK-MB and cTnI levels.

CONCLUSIONS

In non-diabetic patients with CHD, the administration of GIK may increase the risk of PMI due to hypoglycemia induced by GIK.

What is considered cardiotoxicity of anthracyclines in animal studies

Anthracyclines are commonly used anticancer drugs with well-known and extensively studied cardiotoxic effects in humans. In the clinical setting guidelines for assessing cardiotoxicity are well-established with important therapeutic implications. Cardiotoxicity in terms of impairment of cardiac function is largely diagnosed by echocardiography and based on objective metrics of cardiac function. Until this day, cardiotoxicity is not an endpoint in the current general toxicology and safety pharmacology preclinical studies, although other classes of drugs apart from anthracyclines, along with everyday chemicals have been shown to manifest cardiotoxic properties. Also, in the relevant literature there are not well-established objective criteria or reference values in order to uniformly characterize cardiotoxic adverse effects in animal models. This in depth review focuses on the evaluation of two important echocardiographic indices, namely ejection fraction and fractional shortening, in the literature concerning anthracycline administration to rats as the reference laboratory animal model. The analysis of the gathered data gives promising results and solid prospects for both, defining anthracycline cardiotoxicity objective values and delineating the guidelines for assessing cardiotoxicity as a separate hazard class in animal preclinical studies for regulatory purposes.

The role of metabolic diseases in cardiotoxicity associated with cancer therapy: What we know, what we would know

Metabolic diseases, such as obesity and type 2 diabetes, are known risk factors for cardiovascular (CV) diseases. Thus, patients with those comorbidities could be at increased risk of experiencing cardiotoxicity related to treatment with Anthracyclines and the other new generation targeted anticancer drugs. However, investigations addressing the mechanisms underlying the development of CV complications and poor outcome in such cohort of patients are still few and controversial. Given the importance of a personalized approach against chemotherapy-induced cardiomyopathy, this review summarizes our current knowledge on the pathophysiology of chemotherapy-induced cardiomyopathy and its association with obesity and type 2 diabetes. Along with clinical evidences, future perspectives of preclinical research around this field and its role in addressing important open questions, including the development of more proactive strategies for prevention, and treatment of cardiotoxicity during and after chemotherapy in the presence of metabolic diseases, is also presented.

Extracellular vesicular microRNAs as potential biomarker for early detection of doxorubicin-induced cardiotoxicity

Background

Long‐term use of doxorubicin (DOX) is limited by cumulative dose‐dependent cardiotoxicity.

Objectives

Identify plasma extracellular vesicle (EV)‐associated microRNAs (miRNAs) as a biomarker for cardiotoxicity in dogs by correlating changes with cardiac troponin I (cTnI) concentrations and, echocardiographic and histologic findings.

Animals

Prospective study of 9 client‐owned dogs diagnosed with sarcoma and receiving DOX single‐agent chemotherapy (total of 5 DOX treatments). Dogs with clinically relevant metastatic disease, preexisting heart disease, or breeds predisposed to cardiomyopathy were excluded.

Methods

Serum concentration of cTnI was monitored before each treatment and 1 month after the treatment completion. Echocardiography was performed before treatments 1, 3, 5, and 1 month after completion. The EV‐miRNA was isolated and sequenced before treatments 1 and 3, and 1 month after completion.

Results

Linear mixed model analysis for repeated measurements was used to evaluate the effect of DOX. The miR‐107 (P = .03) and miR‐146a (P = .02) were significantly downregulated whereas miR‐502 (P = .02) was upregulated. Changes in miR‐502 were significant before administration of the third chemotherapeutic dose. When stratifying miRNA expression for change in left ventricular ejection fraction, upregulation of miR‐181d was noted (P = .01). Serum concentration of cTnI changed significantly but only 1 month after treatment completion, and concentrations correlated with left ventricular ejection fraction and left ventricular internal dimension in diastole.

Conclusion and Clinical Significance

Downregulation of miR‐502 was detected before significant changes in cTnI concentrations or echocardiographic parameters. Further validation using a larger sample size will be required.

Phoenix dactylifera Protects against Doxorubicin-Induced Cardiotoxicity and Nephrotoxicity

Doxorubicin (DOX) is an important anticancer drug used widely in the treatment of leukemia and lymphoma. The suitability of DOX is enhanced by its high therapeutic index, but its potential to cause cardiotoxicity and nephrotoxicity remains a prime concern in anticancer therapeutics. This study is designed to determine the effect of Phoenix dactylifera extract (PDE) on DOX-induced cardiotoxicity and nephrotoxicity. Experimental rats were divided into four groups, receiving normal saline 4 ml/kg, DOX alone, and crude extract of PDE at doses of 1 g/kg and 1.5 g/kg in the presence of DOX, respectively, for 21 days. Cardiac enzymes and serum and urinary sodium and potassium levels were evaluated which were analyzed statistically by using one-way ANOVA. Subsequently, DOX initiated changes in the level of cardiac markers CK-MB, LDH, and troponin I, which were notably reversed by PDE. PDE was also effective against serum and urinary sodium and urinary potassium and protected against DOX-induced nephrotoxicity. Groups treated with different doses of PDE showed marked decrease in levels of cardiac and renal markers. The study concluded that the PDE extract possesses protective effects against DOX-induced cardiotoxicity and nephrotoxicity.

Doxorubicin-Induced Cardiotoxicity in Collaborative Cross (CC) Mice Recapitulates Individual Cardiotoxicity in Humans

Anthracyclines cause progressive cardiotoxicity whose ultimate severity is individual to the patient. Genetic determinants contributing to this variation are difficult to study using current mouse models. Our objective was to determine whether a spectrum of anthracycline induced cardiac disease can be elicited across 10 Collaborative Cross mouse strains given the same dose of doxorubicin. Mice from ten distinct strains were given 5 mg/kg of doxorubicin intravenously once weekly for 5 weeks (total 25 mg/kg). Mice were killed at acute or chronic timepoints. Body weight was assessed weekly, followed by terminal complete blood count, pathology and a panel of biomarkers. Linear models were fit to assess effects of treatment, sex, and sex-by-treatment interactions for each timepoint. Impaired growth and cardiac pathology occurred across all strains. Severity of these varied by strain and sex, with greater severity in males. Cardiac troponin I and myosin light chain 3 demonstrated strain- and sex-specific elevations in the acute phase with subsequent decline despite ongoing progression of cardiac disease. Acute phase cardiac troponin I levels predicted the ultimate severity of cardiac pathology poorly, whereas myosin light chain 3 levels predicted the extent of chronic cardiac injury in males. Strain- and sex-dependent renal toxicity was evident. Regenerative anemia manifested during the acute period. We confirm that variable susceptibility to doxorubicin-induced cardiotoxicity observed in humans can be modeled in a panel of CC strains. In addition, we identified a potential predictive biomarker in males. CC strains provide reproducible models to explore mechanisms contributing to individual susceptibility in humans.

Evaluating the protective potency of Acacia hydaspica R. Parker on histological and biochemical changes induced by Cisplatin in the cardiac tissue of rats

Background

Increase oxidative trauma is the main cause behind Cisplatin (CP) induced cardiotoxicity which restricts its clinical application as anti-neoplastic prescription. Acacia hydaspica is a natural shrub with diverse bioactivities. Acacia hydaspica ethyl acetate extract (AHE) ameliorated drug-induced cardiotoxicity in animals with anti-oxidative mechanisms. Current study aimed to evaluate the protective potential of A. hydaspica against cisplatin-induced myocardial injury.

Methods

Rats were indiscriminately distributed into six groups (n = 6). Group 1: control; Groups 2: Injected with CP (7.5 mg/kg bw, i.p, single dose) on day 16; Group 3: Treated for 21 days with AHE (400 mg/kg b.w, oral); Group 4: Received CP injection on day 16 and treated with AHE for 5 days post injection; Group 5: Received AHE (400 mg/kg b.w/day, p.o.) for 21 days and CP (7.5 mg/kg b.w., i.p.) on day 16; Group 6: Treated with silymarin (100 mg/kg b.w., p.o.) after 1 day interval for 21 days and CP injection (7.5 mg/kg b.w., i.p.) on day 16. On 22nd day, the animals were sacrificed and their heart tissues were removed. Cisplatin induced cardiac toxicity and the influence of AHE were evaluated by examination of serum cardiac function markers, cardiac tissue antioxidant enzymes, oxidative stress markers and histology.

Results

CP inoculation considerably altered cardiac function biomarkers in serum and diminished the antioxidant enzymes levels, while increased oxidative stress biomarkers in cardiac tissues AHE treatment attenuated CP-induced deteriorations in creatine kinase (CK), Creatine kinase isoenzymes MB (CK-MB), cardiac Troponin I (cTNI) and lactate dehydrogenase (LDH) levels and ameliorated cardiac oxidative stress markers as evidenced by decreasing lipid peroxidation, H₂O₂ and NO content along with augmentation in phase I and phase II antioxidant enzymes. Additionally, CP inoculation also induced morphological alterations which were ameliorated by AHE. In pretreatment group more significant protection was observed compared to post-treatment group indicating preventive potential of AHE. The protective potency of AHE was comparable to silymarin.

Conclusion

Results demonstrate that AHE attenuated CP induce cardiotoxicity. The polyphenolic metabolites and antioxidant properties of AHE might be responsible for its protective influence.

The effect of rutin on cisplatin-induced oxidative cardiac damage in rats

Objective:

Cisplatin is an anticancer drug used for treating childhood solid tumors. Symptoms related to cisplatin-induced cardiovascular adverse effects may be mild or severe. Rutin (vitamin P1) has many properties, including as antioxidant, anticancer, antidiabetic, antimicrobial, antiulcer, and tissue renewal properties. Therefore, we aimed to biochemically, histopathologically, and immunohistochemically demonstrate the effect of rutin on cisplatin-induced cardiotoxicity in rats.

Methods:

The rats included in our study were divided into four groups: Healthy group (HE), 5-mg/kg cisplatin group (CP), 50 mg/kg rutin+5-mg/kg cisplatin (CR-50), 100-mg/kg rutin+5-mg/kg cisplatin (CR-100) group.

Results:

CP group administered cisplatin had significantly increased blood, serum, and cardiac tissue malondialdehyde (MDA), interleukin 1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), troponin I, creatine kinase (CK), and CK-MB levels compared to the HE group, whereas there was a significant decrease in the total glutathione (tGSH) levels. Rutin was observed to prevent the increase in MDA, IL-1β, TNF-α, troponin I, CK, and CK-MB levels as well as prevent the decrease in tGSH levels more significantly when administered at a 100-mg/kg dose than at a 50-mg/kg dose. Histopathologically, cardiac necrosis, dilated/congested blood vessels, hemorrhage, polymorphonuclear leukocyte, edema, and cells with pyknotic nuclei were observed in the CP group. Rutin was shown to prevent cisplatin-induced cardiac damage more effectively when used at a100-mg/kg dose than at a 50-mg/kg dose.

Conclusion:

These results suggest that rutin is useful for preventing cisplatin-related cardiovascular damage

Protective Effect of Kolaviron on Cyclophosphamide-Induced Cardiac Toxicity in Rats

BACKGROUND

Cyclophosphamide (CP) is a nitrogen mustard alkylating drug used for the treatment of chronic and acute malignant lymphomas, myeloma, leukemia, neuroblastoma, adenocarcinoma, retinoblastoma, breast carcinoma, and immunosuppressive therapy. Despite its vast therapeutic uses, it is known to cause severe cardiac toxicity. Kolaviron (KV), a Garcinia kola seed extract containing a mixture of flavonoids, is reputed for its antioxidant and membrane stabilizing properties.

OBJECTIVE

This study investigated the protective effect of KV on CP-induced cardiotoxicity in rats.

METHODS

Thirty rats were used, and they were divided into 6 groups of 5 rats each. Group I received 2 mL/kg propylene glycol orally for 14 days; group II received CP (50 mg/kg/d, intraperitoneally [i.p.]) for 3 days; groups III and IV received 200 and 400 mg/kg/d KV, respectively, orally for 14 days and groups V and VI were pretreated with 200 and 400 mg/kg/d KV, respectively, orally for 14 days followed by CP (50 mg/kg/d, i.p.) for 3 days.

RESULTS

CP treatment resulted in a significantly lower food consumption and body weight in rats. The lactate dehydrogenase and creatine kinase enzymes in cardiac tissues of rats treated with CP were significantly higher. In cardiac tissues, 3-day doses of CP resulted in significantly higher heart weight, cardiac troponin I, myeloperoxidase, malondialdehyde, hydrogen peroxide and lower superoxide dismutase, catalase, glutathione peroxidase activities, and reduced glutathione levels. Histological examination of cardiac tissues showed sign of necrosis of myocardium after CP treatment. However, administration of KV at 200 and 400 mg/kg for 14 days prior to CP treatment, increase food consumption, body weight, and attenuates the biochemical and histological changes induced by CP.

CONCLUSIONS

These results revealed that KV attenuates CP-induced cardiotoxicity by inhibiting oxidative stress and preserving the activity of antioxidant enzymes.

Incidence and risk factors associated with development of clinical cardiotoxicity in dogs receiving doxorubicin

Background

Doxorubicin (DOX) can cause cumulative cardiotoxicity in dogs, but the incidence of clinical cardiotoxicity in dogs receiving DOX has not been determined.

Hypothesis/Objectives

To determine if the duration of DOX infusion influences the incidence of cardiotoxicity, to characterize the incidence of clinical cardiotoxicity in dogs during or after DOX chemotherapy, and to identify any risk factors associated with cardiotoxicity.

Animals

Four‐hundred ninety‐four dogs that received at least 1 dose of DOX for the treatment of cancer.

Methods

Retrospective study of dogs that received DOX from 2006 to 2015.

Results

Of 494 dogs, 20 (4.0%) developed clinical cardiotoxicity. The duration of DOX infusion was not significantly associated with clinical cardiotoxicity, whereas a higher cumulative dose of DOX, higher body weight, decreases in fractional shortening after 5 doses of DOX, and development of ventricular premature contractions were significantly associated with clinical cardiotoxicity. High‐risk breeds for developing dilated cardiomyopathy had an incidence of 15.4%, whereas low‐risk breeds had an incidence of 3.0%.

Conclusions and Clinical Importance

Although the duration of DOX infusion did not influence the incidence of cardiotoxicity, premature contractions and decreases in fractional shortening should raise concern for the development of clinical cardiotoxicity. Overall, the incidence of clinical DOX‐induced cardiotoxicity is low, but Boxers and other breeds at high risk for dilated cardiomyopathy may be at an increased risk.

Cardiovascular variability and β-ARs gene expression at two stages of doxorubicin - Induced cardiomyopathy

Using comprehensive analysis of heart rate (HRV) and blood pressure (BPV) short-term variability we estimated the time course of changes of autonomic nervous system remodeling in two stages of doxorubicin-induced cardiomyopathy (DCM). We also investigated the level of gene expression of cardiac β-1 (β-1AR) and β-2 (β-2AR) adrenoceptors. Experiments were performed in adult male Wistar rats equipped with indwelling catheters for BP recording and blood withdrawal. A 15 mg/kg total cumulative dose of doxorubicin was injected i.p. to rats to induce DCM or saline for control (n=18). Rats were assessed for general toxicity, cardiovascular hemodynamic and echocardiography before treatment (n=6), 35 days (DOX35; n=6) and 70 days (DOX70; n=6) post-treatment. HRV was evaluated by spectral analysis, Poincaré plots, sample and approximate entropy. Expression of β-1AR and β-2AR mRNA was evaluated by RT-qPCR. Doxorubicin-treated rats exhibited poor general condition and lower survival than saline-treated rats. In DOX35 rats, there were no echocardiography signs of decompensation, no increase in serum cardiac troponins, but there was an increase of HRV and decrease of HR complexity. In these rats typical microscopic signs of cardiotoxicity were seen along with over-expression of β-1AR mRNA. 70 days post-treatment echocardiography revealed signs of decompensation and serum cardiac troponin T was increased. At this stage BPV decreased. In conclusion, HRV increase matches transient over-expression of cardiac β-1AR mRNA in compensate stage of DCM while decompensate stage of DCM is characterized by a decrease of BPV and no changes in β-1AR and β-2AR gene expression.

Co-targeting of DNA, RNA, and protein molecules provides optimal outcomes for treating osteosarcoma and pulmonary metastasis in spontaneous and experimental metastasis mouse models

Metastasis is a major cause of mortality for cancer patients and remains as the greatest challenge in cancer therapy. Driven by multiple factors, metastasis may not be controlled by the inhibition of single target. This study was aimed at assessing the hypothesis that drugs could be rationally combined to co-target critical DNA, RNA and protein molecules to achieve saturation attack against metastasis. Independent actions of the model drugs DNA-intercalating doxorubicin, RNA-interfering miR-34a and protein-inhibiting sorafenib on DNA replication, RNA translation and protein kinase signaling in highly metastatic, human osteosarcoma 143B cells were demonstrated by the increase of? H2A.X foci formation, reduction of c-MET expression and inhibition of Erk1/2 phosphorylation, respectively, and optimal effects were found for triple-drug combination. Consequently, triple-drug treatment showed a strong synergism in suppressing 143B cell proliferation and the greatest effects in reducing cell invasion. Compared to single- and dual-drug treatment, triple-drug therapy suppressed pulmonary metastases and orthotopic osteosarcoma progression to significantly greater degrees in orthotopic osteosarcoma xenograft/spontaneous metastases mouse models, while none showed significant toxicity. In addition, triple-drug therapy improved the overall survival to the greatest extent in experimental metastases mouse models. These findings demonstrate co-targeting of DNA, RNA and protein molecules as a novel therapeutic strategy for the treatment of metastasis.

Rat Model of Cardiotoxic Drug-Induced Cardiomyopathy

Cardiotoxicity from cancer drugs remains a clinical problem. To find reliable markers of cardiotoxicity, animal models were proposed and potential new diagnostic markers have been actively investigated using these models. Here we describe our protocols, using male Sprague-Dawley rats, for inducing cardiomyopathy by single injection of high-dose doxorubicin (5-10 mg/kg) or multiple injections (2-4 times) of low-dose doxorubicin (2.5 mg/kg) with combined single injection of trastuzumab (10 mg/kg). The cardiotoxicity is evaluated by imaging modalities (echocardiography and nuclear imaging), serum troponin levels, and histopathological analyses.

Early Evidence of Cardiotoxicity and Tumor Response in Patients with Sarcomas after High Cumulative Dose Doxorubicin Given as a Continuous Infusion

BACKGROUND

Despite the dose-dependent response rate of sarcomas to doxorubicin, clinicians limit its cumulative dose due to cardiotoxicity. This study evaluates early evidence of cardiotoxicity in patients treated with high-dose doxorubicin given as a continuous infusion.

METHODS

Data was collected on patients who received 90 mg/m² doxorubicin as a continuous infusion and 10 gm/m² ifosfamide for up to 6 cycles as part of a phase II study. Cardiotoxicity was assessed with serial echocardiograms or multigated acquisition scans and serum brain natriuretic peptide and troponin levels. Tumor responses were determined by serial radiographic imaging per RECIST.

RESULT

Out of the 48 patients enrolled, no patient developed heart failure symptoms; however, 4 out of the 38 (10%) patients with serial left ventricular ejection fraction assessments developed subclinical cardiotoxicity (asymptomatic drop in LVEF ≥ 10%). Twenty-three patients received all six 72-hour cycles of doxorubicin with a mean cumulative dose of 540 mg/m². Among these patients, 4% (n = 1) developed subclinical cardiotoxicity. In the advanced disease group (n = 39), patients with a complete or partial response received a higher mean cumulative dose than those with stable disease (p < 0.033).

CONCLUSIONS

Doxorubicin cardiotoxicity can be limited by administering doxorubicin as a continuous infusion, allowing higher cumulative dosing to maximize efficacy.

Cardiac autonomic modulation induced by doxorubicin in a rodent model of colorectal cancer and the influence of fullerenol pretreatment

The very effective anticancer drug doxorubicin (DOX) is known to have cardiotoxic side effects, which could be accompanied by autonomic modulation. Autonomic disbalance might even be an initiating mechanism underlying DOX-induced cardiotoxicity and can be studied noninvasively by the analysis of heart rate variability (HRV). A number of strategies have been assessed to predict chemotherapy-induced cardiac dysfunction while HRV, a potential detecting tool, has not yet been tested. Thus, we aimed to determine the effect of DOX treatment on HRV in a rat model of colorectal cancer. While pretreatment with fullerenol (Frl) acts protectively on DOX-induced cardiotoxicity, we aimed to test the effect of Frl pretreatment on DOX-induced HRV alterations. After the induction of colorectal cancer, adult male Wistar rats were treated with saline (n = 7), DOX (1.5 mg/kg per week, n = 7) or DOX after pretreatment with Frl (25 mg/kg per week, n = 7) for three weeks (cumulative DOX dose 4.5 mg/kg). One week after treatment rats were anaesthetized, standard ECG was measured and HRV was analyzed in time and frequency domain. During autopsy the intestines and hearts were gathered for biochemical analysis and histopathological examination. DOX treatment significantly decreased parasympathetically mediated high-frequency component (p<0.05) and increased the low-frequency component of HRV (p<0.05), resulting in an increased LF/HF ratio (p<0.05) in cancerous rats. When pretreated with Frl, DOX-induced HRV alterations were prevented: the high-frequency component of HRV increased (p<0.01), the low-frequency decreased (p<0.01), LF/HF ratio decreased consequently (p<0.01) compared to DOX only treatment. In all DOX-treated animals, disbalance of oxidative status in heart tissue and early myocardial lesions were found and were significantly reduced in rats receiving Frl pretreatment. Autonomic modulation accompanied the development of DOX-induced cardiotoxicity in rat model of colorectal cancer and was prevented by Frl pretreatment. Our results demonstrated the positive prognostic power of HRV for the early detection of DOX-induced cardiotoxicity.

Cardiac Fibrosis and Arrhythmogenesis

Myocardial injury, mechanical stress, neurohormonal activation, inflammation, and/or aging all lead to cardiac remodeling, which is responsible for cardiac dysfunction and arrhythmogenesis. Of the key histological components of cardiac remodeling, fibrosis either in the form of interstitial, patchy, or dense scars, constitutes a key histological substrate of arrhythmias. Here we discuss current research findings focusing on the role of fibrosis, in arrhythmogenesis. Numerous studies have convincingly shown that patchy or interstitial fibrosis interferes with myocardial electrophysiology by slowing down action potential propagation, initiating reentry, promoting after-depolarizations, and increasing ectopic automaticity. Meanwhile, there has been increasing appreciation of direct involvement of myofibroblasts, the activated form of fibroblasts, in arrhythmogenesis. Myofibroblasts undergo phenotypic changes with expression of gap-junctions and ion channels thereby forming direct electrical coupling with cardiomyocytes, which potentially results in profound disturbances of electrophysiology. There is strong evidence that systemic and regional inflammatory processes contribute to fibrogenesis (i.e., structural remodeling) and dysfunction of ion channels and Ca2+ homeostasis (i.e., electrical remodeling). Recognizing the pivotal role of fibrosis in the arrhythmogenesis has promoted clinical research on characterizing fibrosis by means of cardiac imaging or fibrosis biomarkers for clinical stratification of patients at higher risk of lethal arrhythmia, as well as preclinical research on the development of antifibrotic therapies. At the end of this review, we discuss remaining key questions in this area and propose new research approaches. © 2017 American Physiological Society. Compr Physiol 7:1009-1049, 2017.

Asialoglycoprotein receptor targeted delivery of doxorubicin nanoparticles for hepatocellular carcinoma

We report asialoglycoprotein receptor (ASGPR)-targeted doxorubicin hydrochloride (Dox) nanoparticles (NPs) for hepatocellular carcinoma (HCC). Polyethylene sebacate (PES)-Gantrez® AN 119 Dox NPs of average size 220 nm with PDI < 0.62 and ∼20% Dox loading were prepared by modified nanoprecipitation. ASGPR ligands, pullulan (Pul), arabinogalactan (AGn), and the combination (Pul-AGn), were anchored by adsorption. Ligand anchoring enabled high liver uptake with a remarkable hepatocyte:nonparenchymal cell ratio of 85:15. Furthermore, Pul-AGn NPs exhibited an additive effect implying incredibly high hepatocyte accumulation. Galactose-mediated competitive inhibition confirmed ASGPR-mediated uptake of ligand-anchored NPs in HepG2 cell lines. Subacute toxicity in rats confirmed the safety of the NP groups. However, histopathological evaluation suggested mild renal toxicity of AGn. Pul NPs revealed sustained reduction in tumor volume in PLC/PRF/5 liver tumor-bearing Nod/Scid mice up to 46 days. Extensive tumor necrosis, reduced collagen content, reduction in the HCC biomarker serum α-fetoprotein (p < 0.05), a mitotic index of 1.135 (day 46), and tumor treated/tumor control (T/C) values of <0.42 signified superior efficacy of Pul NPs. Furthermore, weight gain in the NP groups, and no histopathological alterations indicated that they were well tolerated by the mice. The high efficacy coupled with greater safety portrayed Pul Dox NPs as a promising nanocarrier for improved therapy of HCC.

Hemodynamic effects of HPMA copolymer based doxorubicin conjugate: A randomized controlled and comparative spectral study in conscious rats

Conjugation of Doxorubicin (DOX) to N-(2-hydroxypropyl) methylacrylamide copolymer (HPMA) has significantly reduced the DOX-associated cardiotoxicity. However, the reports on the impact of HPMA–DOX conjugates on the cardiovascular system such as blood pressure (BP) and heart rate (HR) were in restrained animals using tail cuff and/or other methods that lacked the resolution and sensitivity. Herein, we employed radiotelemetric-spectral-echocardiography approach to further understand the in vivo cardiovascular hemodynamics and variability post administration of free DOX and HPMA–DOX. Rats implanted with radio-telemetry device were administered intravenously with DOX (5 mg/kg), HPMA–DOX (5 mg DOX equivalent/kg) and HPMA copolymer and subjected to continuous cardiovascular monitoring and echocardiography for 140 days. We found that DOX-treated rats had ruffled fur, reduced body weight (BW) and a low survival rate. Although BP and HR were normal, spectral analysis indicated that their BP and HR variabilities were reduced. All rats exhibited typical signs of cardiotoxicity at histopathology. In contrast, HPMA–DOX rats gained weight over time and survived. Although BP, HR and related variabilities were unaffected, the left ventricular end diastolic volume (EDV) of these rats, as well as of the HPMA copolymer-treated rats, was found increased at the end of observation period. Additionally, HPMA copolymer caused microscopic injury of the heart tissue. All of these suggest the necessity of caution when employing HPMA as carrier for prolonged drug delivery. The current study also indicates the potential of radiotelemetric-spectral-echocardiography approach for improved preclinical cardiovascular risk assessment of polymer–drug conjugate and other nano-sized-drug constructs.

Drug-Loaded Mesoporous Tantalum Oxide Nanoparticles for Enhanced Synergetic Chemoradiotherapy with Reduced Systemic Toxicity

Combining chemotherapy and radiotherapy (chemoradiotherapy) has been widely applied in many clinical practices, showing promises in enhancing therapeutic outcomes. Nontoxic nanocarriers that not only are able to deliver chemotherapeutics into tumors, but could also act as radiosensitizers to enhance radiotherapy would thus be of great interest in the development of chemoradiotherapies. To achieve this aim, herein mesoporous tantalum oxide (mTa₂ O₅ ) nanoparticles with polyethylene glycol (PEG) modification are fabricated. Those mTa₂ O₅ -PEG nanoparticles could serve as a drug delivery vehicle to allow efficient loading of chemotherapeutics such as doxorubicin (DOX), whose release appears to be pH responsive. Meanwhile, owing to the interaction of Ta with X-ray, mTa₂ O₅ -PEG nanoparticles could offer an intrinsic radiosensitization effect to increase X-ray-induced DNA damages during radiotherapy. As a result, DOX-loaded mTa₂ O₅ -PEG (mTa₂ O₅ -PEG/DOX) nanoparticles can offer a strong synergistic therapeutic effect during the combined chemoradiotherapy. Furthermore, in chemoradiotherapy, such mTa₂ O₅ -PEG/DOX shows remarkably reduced side effects compared to free DOX, which at the same dose appears to be lethal to animals. This work thus presents a new type of mesoporous nanocarrier particularly useful for the delivery of safe and effective chemoradiotherapy.

The human amniotic fluid stem cell secretome effectively counteracts doxorubicin-induced cardiotoxicity

The anthracycline doxorubicin (Dox) is widely used in oncology, but it may cause a cardiomyopathy with bleak prognosis that cannot be effectively prevented. The secretome of human amniotic fluid-derived stem cells (hAFS) has previously been demonstrated to significantly reduce ischemic cardiac damage. Here it is shown that, following hypoxic preconditioning, hAFS conditioned medium (hAFS-CM) antagonizes senescence and apoptosis of cardiomyocytes and cardiac progenitor cells, two major features of Dox cardiotoxicity. Mechanistic studies with mouse neonatal ventricular cardiomyocytes (mNVCM) reveal that hAFS-CM inhibition of Dox-elicited senescence and apoptosis is associated with decreased DNA damage, nuclear translocation of NF-kB, and upregulation of the NF-kB controlled genes, Il6 and Cxcl1, promoting mNVCM survival. Furthermore, hAFS-CM induces expression of the efflux transporter, Abcb1b, and Dox extrusion from mNVCM. The PI3K/Akt signaling cascade, upstream of NF-kB, is potently activated by hAFS-CM and pre-treatment with a PI3K inhibitor abrogates NF-kB accumulation into the nucleus, modulation of Il6, Cxcl1 and Abcb1b, and prevention of Dox-initiated senescence and apoptosis in response to hAFS-CM. These results support the concept that hAFS are a valuable source of cardioprotective factors and lay the foundations for the development of a stem cell-based paracrine treatment of chemotherapy-related cardiotoxicity.

Mitochondria and nuclei dual-targeted heterogeneous hydroxyapatite nanoparticles for enhancing therapeutic efficacy of doxorubicin

Dual-targeted nanoparticles have been increasingly used to realize greater anti-proliferation effect by attacking double key sites of tumor cells. In order to retain nuclei inhibition effect and enhance DOX-induced apoptosis by mitochondrial pathway simultaneously, hyaluronic acid (HA) modified hydroxyapatite (HAP) nanoparticles (HAP-HA), the functional calcium-based tumor targeting nanoparticles, have been developed. In this nanosystem, HA acts as an active tumor-targeting ligand to bind the CD44 receptors which are overexpressed on the surface of tumor cells while HAP can load and deliver DOX to both nuclei and mitochondria of tumor cells. In this study, DOX-loaded HAP-HA nanoparticles (DOX/HAP-HA) exhibited satisfactory drug loading efficiency which was up to 214.55 ± 51.05 μg mg(-1) and showed a uniform nano-scaled particle size. The mitochondrial and nuclei targetability of DOX/HAP-HA was confirmed by confocal laser scanning microscopy analyses. Besides, western blot assay demonstrated that DOX/HAP-HA could markedly enhance mitochondrial cytochrome C leakage and thereby activate apoptotic cascade associated with it. In addition, in vivo anti-tumor efficacy and toxicity evaluation of DOX/HAP-HA indicated that DOX/HAP-HA was more effective and less harmful compared to other groups. DOX/HAP-HA might be a new promising targeted delivery system for effective cancer therapy.

Growth-differentiation Factor-15 and Tissue Doppler Imaging in Detection of Anthracycline-induced Cardiomyopathy During Therapy of Childhood Cancers

OBJECTIVES

The aim of this study was to evaluate the importance of growth-differentiation factor-15 (GDF-15) levels and tissue Doppler imaging (TDI) in the early detection of anthracycline-induced cardiomyopathy during the treatment of childhood cancers.

PATIENTS AND METHODS

Twenty patients (13 males and 7 females) newly diagnosed with childhood cancer whose treatment protocol included anthracycline were included in the study. Echocardiography, including M-mode, pulse Doppler, and TDI, was performed after the first anthracycline treatment at cumulative doses of 100, 200, and 300 mg/m and at least 6 months after the last treatment. GDF-15 and troponin-I were also measured at these time points.

RESULTS

The median age of the patients was 14 years (range, 3 to 18 y). The median cumulative anthracycline dose was 220 mg/m (range, 60 to 400 mg/m). Conventional pulse wave and pulse wave tissue Doppler methods revealed significant differences in the right ventricular myocardial performance indices of the patients who received cumulative anthracycline doses of 300 mg/m compared with their indices at least 6 months after the last treatment. The serum GDF-15 levels after the cumulative anthracycline dose of 200 mg/m were also higher than the patients' pretreatment levels.

CONCLUSIONS

Doppler/TDI and GDF-15 levels may be used in the early determination of anthracycline-induced cardiomyopathy during the treatment of childhood cancers.

Evaluation of potential acute cardiotoxicity of biodegradable nanocapsules in rats by intravenous administration

Nanotoxicology aims to study the safety of nanomaterials, especially towards human exposure. Biodegradable polymeric nanocapsules have been indicated as potential drug carriers applicable for treating several pathologies. Thus, the objective of this study was to evaluate the potential cardiotoxicity of biodegradable lipid-core nanocapsules (LNC) containing poly(ε-caprolactone). Nanocapsules were characterized and the acute toxicity evaluation was conducted in Wistar rats. Two control groups (saline and tween/glycerol) were utilized, and three treated groups were chosen for low, intermediate and high doses: 28.7 × 1012 (LNC-1), 57.5 × 1012 (LNC-2) and 115 × 1012 (LNC-3), expressed as number of nanocapsules per milliliter per kg. Blood pressure measurements were performed in non-anesthetized animals by caudal plethysmography. The electrocardiographic (ECG) and echocardiographic analyses were carried out after anesthesia by isoflurane at two points, prior to treatment and after 14 days. Blood was collected 24 hours and 14 days after treatment. Biochemical and histopathological analyses were performed. During the evaluation period, no deaths, weight loss or clinical signs were observed. Post-treatment systolic pressures (24 h and 14 days) were significantly increased in comparison to pre-treatment in both control groups and treated groups, which is suggested to be as a possible consequence of the infused volume. Serum sodium, potassium, aspartate aminotransferase and alkaline phosphatase, as well as, hematological parameters were within reference values established for rats. ECG showed no indications of cardiotoxicity. Despite the echocardiograms, no alterations in the ejection fraction were found as indicators of cardiotoxicity. Cardiac histopathology also demonstrated no alterations. Therefore, the present results on acute evaluation after i.v. administration, by slow infusion, showed potential safety since no cardiotoxic effects by ECG, echocardiographic, arterial pressure, biochemical and histopathological analyses were found.

The minipig as a new model for the evaluation of doxorubicin-induced chronic toxicity

Doxorubicin can cause life-threatening toxic effects in several organs, with cardiotoxicity being the major concern. Although a large number of animal models have been utilized to study doxorubicin toxicity, several restrictions limit their use. Since the Göttingen minipig is an accepted species for non-clinical safety assessment and translation to man, we aimed at exploring its use as a non-rodent animal model for safety assessment and regulatory toxicity studies using doxorubicin. Three groups of three males and three females adult Göttingen minipigs received 1.5 mg kg(-1) , 3/2.3 mg kg(-1) or vehicle at intervals of 3 weeks for 7 cycles. Doxorubicin treatment resulted in a dose-related decrease in the erythrocytes, hemoglobin and hematocrit count, accompanied by leukopenia and thrombocytopenia. Bone marrow smears revealed dose-related hypocellularity. Urea and creatinine levels were elevated in treated animals, associated with proteinuria and hematuria. Histopathological evaluation detected nephropathy and atrophy of hematopoietic tissues/organs, mucosa of the intestinal tract and male genital tract. Cardiac lesions including chronic inflammation, endocardial hyperplasia, hemorrhage and myxomatous changes were evident in hematoxylin and eosin stains, and evaluation of semi-thin sections showed the presence of dose-related vacuolation in the atrial and ventricular cardiomyocytes. Cardiac troponin levels were increased in the high-dose group, but there was no direct correlation to the severity of the histopathological lesions. This study confirms that the Göttingen minipig has a comparable toxicity profile to humans and considering its anatomical, physiological, genetic and biochemical resemblance to humans, it should be considered as the non-rodent species of choice for studies on doxorubicin toxicity. Copyright © 2015 John Wiley & Sons, Ltd.

Translating extracellular microRNA into clinical biomarkers for drug-induced toxicity: from high-throughput profiling to validation

Over the past 5 years, extracellular microRNAs (miRNAs) are being vigorously explored as injury biomarkers, including drug-induced cardiotoxicity, hepatotoxicity and nephrotoxicity. Currently, the development of miRNAs as clinical biomarkers has been hindered by the lack of standardization. Therefore, extracellular miRNA-based biomarkers have not been embraced as diagnostic tools. Each platform has its strengths and weaknesses when working with low-input-amount RNA samples from body fluids; the selection of a miRNA quantification approach should be based on the study design. The following review provides a summary of the extracellular miRNA release and stability in body fluids, performances of different miRNA quantification platforms, existing clinical gold standards for drug-induced tissue damage and translation of the miRNA biomarkers from the nonclinical to clinical setting.

Experimental determination of diagnostic window of cardiac troponins in the development of chronic anthracycline cardiotoxicity and estimation of its predictive value

BACKGROUND

Cardiac troponins (cTns) seem to be more sensitive for the detection of anthracycline cardiotoxicity than the currently recommended method of monitoring LV systolic function. However, the optimal timing of blood sampling remains unknown. Hence, the aims of the present study were to determine the precise diagnostic window for cTns during the development of chronic anthracycline cardiotoxicity and to evaluate their predictive value.

METHODS

Cardiotoxicity was induced in rabbits with daunorubicin (3mg/kg, weekly, for 8 weeks). Blood samples were collected 2-168 h after the 1st, 5th and 8th drug administrations, and concentrations of cTns were determined using highly sensitive assays: hs cTnT (Roche) and hs cTnI (Abbott).

RESULTS

The plasma levels of cTns progressively increased with the rising number of chemotherapy cycles. While only a mild non-significant increase in both cTn levels occurred after the first daunorubicin dose, a significant rise was observed after the 5th and 8th administrations. Two hours after these administrations, a significant increase occurred with a peak between 4-6h and a decline until 24h. Discrete cTn release continued even after cessation of the therapy. While greater variability of cTn levels was observed around the peak concentrations, the values did not correspond well with the severity of LV systolic dysfunction. Unlike AMI in cardiotoxicity, cTn elevations may be better associated with cumulative dose and concentrations at steady state than cmax.

CONCLUSIONS

To the best of our knowledge, this is the first study to precisely describe the diagnostic window and predictive value of cTns in anthracycline cardiotoxicity.

Cardioprotective effect of metformin against doxorubicin cardiotoxicity in rats

Objective:

The clinical use of doxorubicin, which is a strong antineoplastic agent, is limited due to its cardiotoxic side effects. Metformin is a drug with antihyperglycemic effects, and it has been shown to have a cardioprotective effect on left ventricular function in experimental animal models of myocardial ischemia. The present study investigated the cardioprotective effect of metformin in rats with doxorubicin cardiotoxicity.

Methods:

Wistar albino rats were used in the study. Forty male, 10-week-old Wistar albino rats were randomly divided four groups. The control group rats were intraperitoneally administered saline solution twice a week, four doses in total. The doxorubicin group rats received doxorubicin (4 mg/kg, twice a week, cumulative dose: 16 mg/kg) intraperitoneally. The metformin group rats received metformin (250 mg/kg/day, every day for 14 days) via gavage. The doxorubicin + metformin group rats received doxorubicin and metformin at the same dose. Left ventricular functions were evaluated by using M-mode echocardiography one day after the last dose of doxorubicin. Heart tissue samples were histopathologically examined. Cardiomyocyte apoptosis was detected using in situ terminal deoxynucleotide transferase assay (TUNEL). Serum brain natriuretic peptide and C-type natriuretic peptide levels were measured. Catalase, superoxide dismutase, glutathione peroxidase, and tumor necrosis factor alpha levels were analyzed in the heart tissue. The assumptions of equality of variances and normal distribution were checked for all variables (Shapiro-Wilk test and Q-Q graphics). To identify intergroup differences, one-way variant analysis or the Kruskal-Wallis test was used. A p<0.05 value was accepted as statistically significant.

Results:

Our results showed that doxorubicin treatment caused significant deterioration in left ventricular functions by echocardiography, histological heart tissue damage, and increase in cardiomyocyte apoptosis. Doxorubicin + metformin group showed protection in left ventricular function, elimination of histopathologic change, and reduced of cardiomyocyte apoptosis.

Conclusion:

The present study provided evidence that metformin has cardioprotective effects against doxorubicin cardiotoxicity.

Heart rate dynamics in doxorubicin-induced cardiomyopathy

The clinical use of doxorubicin, an effective chemotherapeutic is hampered by the development of irreversible cardiotoxicity. Here we test time-frequency analysis of heart rate (HR) variability (HRV) for early detection of doxorubicin-induced cardiotoxicity. Experiments were conducted in adult male Wistar rats treated for 15 days with doxorubicin (DOXO, total dose 15 mg kg(-1), i.p.) or saline (CONT). DOXO rats exhibited cardiotoxicity confirmed by histological examination without developing heart failure as estimated by echocardiography. However, HR variability increase reflected subtle microscopic changes of cardiac toxicity in DOXO rats. The results recommend time-frequency analysis of HRV for early detection of doxorubicin-induced cardiomyopathy.

Early biomarkers of doxorubicin-induced heart injury in a mouse model

Cardiac troponins, which are used as myocardial injury markers, are released in plasma only after tissue damage has occurred. Therefore, there is a need for identification of biomarkers of earlier events in cardiac injury to limit the extent of damage. To accomplish this, expression profiling of 1179 unique microRNAs (miRNAs) was performed in a chronic cardiotoxicity mouse model developed in our laboratory. Male B6C3F1 mice were injected intravenously with 3mg/kg doxorubicin (DOX; an anti-cancer drug), or saline once a week for 2, 3, 4, 6, and 8weeks, resulting in cumulative DOX doses of 6, 9, 12, 18, and 24mg/kg, respectively. Mice were euthanized a week after the last dose. Cardiac injury was evidenced in mice exposed to 18mg/kg and higher cumulative DOX dose whereas examination of hearts by light microscopy revealed cardiac lesions at 24mg/kg DOX. Also, 24 miRNAs were differentially expressed in mouse hearts, with the expression of 1, 1, 2, 8, and 21 miRNAs altered at 6, 9, 12, 18, and 24mg/kg DOX, respectively. A pro-apoptotic miR-34a was the only miRNA that was up-regulated at all cumulative DOX doses and showed a significant dose-related response. Up-regulation of miR-34a at 6mg/kg DOX may suggest apoptosis as an early molecular change in the hearts of DOX-treated mice. At 12mg/kg DOX, up-regulation of miR-34a was associated with down-regulation of hypertrophy-related miR-150; changes observed before cardiac injury. These findings may lead to the development of biomarkers of earlier events in DOX-induced cardiotoxicity that occur before the release of cardiac troponins.

An integrated characterization of serological, pathological, and functional events in doxorubicin-induced cardiotoxicity

Many efficacious cancer treatments cause significant cardiac morbidity, yet biomarkers or functional indices of early damage, which would allow monitoring and intervention, are lacking. In this study, we have utilized a rat model of progressive doxorubicin (DOX)-induced cardiomyopathy, applying multiple approaches, including cardiac magnetic resonance imaging (MRI), to provide the most comprehensive characterization to date of the timecourse of serological, pathological, and functional events underlying this toxicity. Hannover Wistar rats were dosed with 1.25 mg/kg DOX weekly for 8 weeks followed by a 4 week off-dosing "recovery" period. Electron microscopy of the myocardium revealed subcellular degeneration and marked mitochondrial changes after a single dose. Histopathological analysis revealed progressive cardiomyocyte degeneration, hypertrophy/cytomegaly, and extensive vacuolation after two doses. Extensive replacement fibrosis (quantified by Sirius red staining) developed during the off-dosing period. Functional indices assessed by cardiac MRI (including left ventricular ejection fraction (LVEF), cardiac output, and E/A ratio) declined progressively, reaching statistical significance after two doses and culminating in "clinical" LV dysfunction by 12 weeks. Significant increases in peak myocardial contrast enhancement and serological cardiac troponin I (cTnI) emerged after eight doses, importantly preceding the LVEF decline to <50%. Troponin I levels positively correlated with delayed and peak gadolinium contrast enhancement, histopathological grading, and diastolic dysfunction. In summary, subcellular cardiomyocyte degeneration was the earliest marker, followed by progressive functional decline and histopathological manifestations. Myocardial contrast enhancement and elevations in cTnI occurred later. However, all indices predated "clinical" LV dysfunction and thus warrant further evaluation as predictive biomarkers.

Exacerbation of celecoxib-induced renal injury by concomitant administration of misoprostol in rats

Nonsteroidal anti-inflammatory drugs (NSAIDs) can produce adverse effects by inhibiting prostaglandin (PG) synthesis. A PGE1 analogue, misoprostol, is often utilized to alleviate NSAID-related gastrointestinal side effects. This study examined the effect of misoprostol on celecoxib renal toxicity. Additionally, the effects of these drugs on cardiovascular parameters were evaluated. Four randomized rat groups were orally gavaged for 9 days, two groups receiving vehicle and two groups receiving misoprostol (100 µg/kg) twice daily. Celecoxib (40 mg/kg) was co-administered once daily to one vehicle and one misoprostol group from days 3 to 9. Urine and blood samples were collected and blood pressure parameters were measured during the study period. Hearts and kidneys were harvested on final day. Day 2 urinary electrolyte samples revealed significant reductions in sodium excretion in misoprostol (0.12 ± 0.05 µmol/min/100 g) and misoprostol+celecoxib groups (0.07 ± 0.02 µmol/min/100 g). At day 3, all treatment groups showed significantly reduced sodium excretion. Potassium excretion diminished significantly in vehicle+celecoxib and misoprostol+celecoxib groups from day 3 onward. Urinary kidney injury molecule-1 levels were significantly increased in vehicle+celecoxib (0.65 ± 0.02 vs. 0.35 ± 0.07 ng/mL, p = 0.0002) and misoprostol+celecoxib (0.61 ± 0.06 vs. 0.37 ± 0.06 ng/mL, p = 0.0015) groups when compared to baseline; while plasma levels of cardiac troponin I increased significantly in vehicle+celecoxib (p = 0.0040) and misoprostol+misoprostol (p = 0.0078) groups when compared to vehicle+vehicle. Blood pressure parameters increased significantly in all misoprostol treated groups. Significant elevation in diastolic (p = 0.0071) and mean blood pressure (p = 0.0153) was noted in misoprostol+celecoxib compared to vehicle+celecoxib. All treatments produced significant tubular dilatation/necrosis compared to control. No significant myocardial changes were noticed; however, three animals presented with pericarditis. Kidney, heart, and plasma celecoxib levels revealed no significant change between vehicle+celecoxib and misoprostol+celecoxib. Concomitant misoprostol administration did not prevent celecoxib renal toxicity, and instead exacerbated renal side effects. Misoprostol did not alter plasma or tissue celecoxib concentrations suggesting no pharmacokinetic interaction between celecoxib and misoprostol.

Blood cardiac troponin in toxic myocardial injury: archetype of a translational safety biomarker

A translational safety biomarker for toxic myocardial injury is needed in drug discovery and development. This need reflects the increasing recognition of occurrence of cardiotoxicities, prior lack of preclinical blood biomarkers for toxic cardiac injury, introduction of troponin as a biomarker, and regulatory and industry drivers. Cardiac troponin is considered the gold-standard biomarker in humans for cardiac injury due to ischemic injury and drug toxicity. It has been demonstrated to correlate highly with histopathological extent of injury, degree of impairment of cardiac function, and prognosis. Numerous studies have now clearly demonstrated that both cardiac troponin T and cardiac troponin I are sensitive and specific biomarkers of cardiac injury in laboratory animals. Their use is highly recommended for incorporation into preclinical drug-safety studies, especially whenever there is any history of cardiac effect in prior studies with a compound of the same or similar chemical or pharmacological class. The main caveats with respect to cross-species use of specific cardiac troponin assays are the need for species-specific validation, definition of cut-offs based on relevant assessments of imprecision and reference ranges or concurrent controls, and knowledge of the species-dependent kinetics of release into, and clearance from, the blood. Future development of high-sensitivity assays should determine whether minimal increases below a threshold concentration of troponin might reflect reversible myocardial effects.