5-Fluorouracil cardiotoxicity: a unique mechanism for ischaemic cardiopathy and cardiac failure?

Changes in cardiac volume determined with repeated enhanced 4DCT during chemoradiotherapy for esophageal cancer

Background

Concurrent chemoradiotherapy is considered curative intent treatment for patients with non-operative esophageal cancer. Radiation-induced heart damage receives much attention. We performed repeated four-dimensional computed tomography (4DCT) to detect changes in cardiac volume during radiotherapy for esophageal cancer patients, and explored potential factors responsible for those changes.

Methods

Forty-six patients with esophageal cancer underwent enhanced 4DCT and three-dimensional (3D) CT scans before radiotherapy and every 10 fractions during treatment. The heart was contoured on 3DCT images, 4DCT end expiratory (EE) images and 4DCT maximum intensity projection (MIP) images by the same radiation oncologist. Heart volumes and other relative parameters were compared by the SPSS software package, version 19.0.

Results

Compared with its initial value, heart volume was smaller at the 10th fraction (reduction = 3.27%, 4.45% and 4.52% on 3DCT, EE and MIP images, respectively, p < 0.05) and the 20th fraction (reduction = 6.05%, 5.64% and 4.51% on 3DCT, EE and MIP images, respectively, p < 0.05), but not at the 30th fraction. Systolic and diastolic blood pressures were reduced (by 16.95 ± 16.69 mmHg and 7.14 ± 11.64 mmHg, respectively, both p < 0.05) and the heart rate was elevated by 5.27 ± 6.25 beats/min (p < 0.05) after radiotherapy. None of the potential explanatory variables correlated with heart volume changes.

Conclusions

Cardiac volume reduced significantly from an early treatment stage and maintained the reduction until the middle stage. The heart volume changes observed on 3DCT and 4DCT were consistent during radiotherapy. The changes in heart volume, blood pressure and heart rate may be valuable indicators of cardiac impairment and target dose changes.

Cardiac lesions induced by 5-fluorouracil in the rabbit

Cardiotoxicity is a rare, but well-recognized complication of treatments with the anti-cancer drug 5-fluorouracil (5FU). The underlying mechanism, however, is not fully elucidated. A spasm of the coronary arteries is often considered to be the leading cause of myocardial ischemia and decreased contractility associated with 5FU. As spasm cannot account for all reported adverse cardiac effects, the present study was undertaken to search for alternative mechanisms. Groups of six rabbits were given either a single intravenous dose of 50 mg/kg 5FU or four intravenous doses of 15 mg/kg 5FU at 7-day intervals. A third group served as control. The heart was removed shortly after death or scheduled sacrifice of the animals, to perform macroscopic and microscopic examinations of the heart and to evidence apoptosis by the TUNEL method. Following a single dose of 50 mg/kg 5FU, all animals rapidly developed a massive hemorrhagic myocardial infarct with spasms of the proximal coronary arteries. Repeated infusions of 15 mg/kg 5FU induced left ventricular hypertrophy, foci of myocardial necrosis, thickening of intra-myocardial arterioles, and disseminated apoptosis in myocardial cells of the epicardium, as well as endothelial cells of the distal coronary arteries. These results indicate that a spasm of the coronary arteries is not the only mechanism of 5FU cardiotoxicity, and that apoptosis of myocardial and endothelial cells can result in inflammatory lesions mimicking toxic myocarditis.

Role of biomarkers in monitoring antiblastic cardiotoxicity

Early detection of anticancer drug-induced cardiotoxicity (CTX) has been evaluated by most international scientific cardiology and oncology societies. High expectations have been placed on the use of specific biomarkers. In recent years, conventional biomarkers and molecules of more recent interest have been tested and compared in the context of anticancer drug-related CTX. Encouraging results were obtained from studies on molecules of myocardial damage, such as troponin and markers of myocardial wall stress, including circulating natriuretic peptides, as well as from the assessment of the products of inflammation or circulating levels of free radicals. However, clear guidelines on their sensitivity, specificity, and accuracy are not yet available, and many challenges, such as the optimal time of assessing, optimal schedule for evaluation, optimal cut-off point for positivity with the highest level of specificity, and optimal comparability of different assays for the measurements, remain unresolved. Given the importance of having a reliable and accurate tool for monitoring anticancer drug-induced CTX, this review will focus on the available data on the most effective and widely used biomarkers and the studies that are currently underway that aim to identify the effectiveness of new approaches in this therapeutic setting.

Reduction of heart volume during neoadjuvant chemoradiation in patients with resectable esophageal cancer

BACKGROUND AND PURPOSE

Neoadjuvant chemoradiation (nCRT) followed by surgery is considered curative intent treatment for patients with resectable esophageal cancer. The aim was to establish hemodynamic aspects of changes in heart volume and to explore whether changes in heart volume resulted in clinically relevant changes in the dose distribution of radiotherapy.

METHODS

A prospective study was conducted in patients who were treated with nCRT consisting of carboplatin and paclitaxel concomitant with radiotherapy (41.4 Gy/1.8 Gy per fraction). Physical parameters, cardiac volume on CT and Cone beam CT, cardiac blood markers and cardiac ultrasound were obtained.

RESULTS

In 23 patients a significant decrease of 55.3 ml in heart volume was detected (95% CI 36.7-73.8 ml, p<0.001). There was a decrease in both systolic (mean decrease 18 mmHg, 95% CI 11-26 mmHg, p<0.001) and diastolic blood pressure (mean decrease 8 mmHg, 95% CI 2-14 mmHg, p=0.008) and an increase in heart rate with 6 beats/min (95% CI 1-11 beats/min, p=0.021). Except for Troponin T, no change in other cardiac markers and echocardiography parameters were observed. The change in heart volume did not result in a clinically relevant change in radiation dose distribution.

CONCLUSION

Heart volume was significantly reduced, but was not accompanied by overt cardiac dysfunction. All observed changes in hemodynamic parameters are consistent with volume depletion. Adaptation of the treatment plan during the course of radiotherapy is not advocated.

Prognostic role of troponin and natriuretic peptides as biomarkers for deterioration of left ventricular ejection fraction after chemotherapy

Cardiotoxicity due to anthracyclines, trastuzumab and other potential cardiotoxic drugs is still a problem of modern chemotherapy. For years researchers have tried to find biological markers that can predict changes in the heart. The most thoroughly tested markers are troponin and natriuretic peptides. Some studies have proven that these markers can indeed be useful. In studies which have shown the predictive role of troponin I the assessment of this marker was performed very frequently. It is not possible to carry out such serial measurements in many centers because of typical 1-day hospital stay times. The predictive role of natriuretic peptides still needs further investigation. This review considers the newest research from recent years.

A comparison of cardiomyocyte cytotoxic mechanisms for 5-fluorouracil and its pro-drug capecitabine

1. 5-Fluorouracil (5-FU) and its prodrug capecitabine are key chemotherapeutic agents in the treatment of many gastrointestinal tract adenocarcinomas. In addition to their beneficial antitumor effects, they also possess undesired cardiac toxicity. In the present study, we investigated the cytotoxic mechanisms of 5-FU and capecitabine in freshly isolated rat cardiomyocytes. 2. 5-FU and capecitabine cytotoxicities were associated with reactive oxygen species (ROS) formation, lipid peroxidation and rapid glutathione depletion. Increased intracellular ROS could target mitochondria, and our findings confirmed that the cardiomyocytes mitochondrial membrane potential (ΔΨm) was rapidly decreased by 5-FU and capecitabine. Mitochondrial dysfunction subsequently initiates downstream events that trigger caspase-3 activation, and our results showed that 5-FU and capecitabine activated caspase-3 which leads to apoptosis or necrosis. However, 5-FU acted much more powerful than capecitabine at inducing several cytotoxicity markers in heart cardiomyocytes. In addition, 5-FU but not capecitabine caused lysosomal membrane leakiness when it was incubated with cardiomyocytes. All cytotoxicity markers were prevented by antioxidants, ROS scavengers, mitochondrial permeability transition (MPT) pore sealing agents and lysosomotropic agents. 3. Our findings showed that the cytotoxic action of 5-FU and capecitabine on cardiomyocytes are mediated by oxidative stress and subsequent mitochondrial dysfunction which causes caspase-3 activation and cell death.

Molecular basis of cancer-therapy-induced cardiotoxicity: introducing microRNA biomarkers for early assessment of subclinical myocardial injury

Development of reliable biomarkers for early clinical assessment of drug-induced cardiotoxicity could allow the detection of subclinical cardiac injury risk in vulnerable patients before irreversible damage occurs. Currently, it is difficult to predict who will develop drug-induced cardiotoxicity owing to lack of sensitivity and/or specificity of currently used diagnostics. miRNAs are mRNA regulators and they are currently being extensively profiled for use as biomarkers due to their specific tissue and disease expression signature profiles. Identification of cardiotoxicity-specific miRNA biomarkers could provide clinicians with a valuable tool to allow prognosis of patients at risk of cardiovascular injury, alteration of a treatment regime or the introduction of an adjunct therapy in order to increase the long-term survival rate of patients treated with cardiotoxic drugs.

5-Fluorouracil induces apoptosis in rat cardiocytes through intracellular oxidative stress

Background

Cardiotoxicity is a major complication of anticancer drugs, including anthracyclines and 5-fluorouracil(5-FU) and it can have detrimental effects both in patients and workers involved in the preparation of chemotherapy.

Methods

Specifically, we have assessed the effects of increasing concentrations of 5-FU and doxorubicin (DOXO) on proliferation of H9c2 rat cardiocytes and HT-29 human colon adenocarcinoma cells by MTT assay. Cells were treated for 24, 48 and 72 h with different concentrations of the two drugs alone or with 5-FU in combination with 10^-4 M of levofolene (LF).

Results

5-FU induced a time- and dose-dependent growth inhibition in both cell lines. The 50% growth inhibition (IC:50) was reached at 72 h with concentrations of 4 μM and 400 μM on HT-29 and H9c2, respectively. The addition of LF to 5-FU enhanced this effect. On the other hand, the IC:50 of DOXO was reached at 72 h with concentrations of 0.118 μM on H9c2 and of 0.31 μM for HT-29. We have evaluated the cell death mechanism induced by 50% growth inhibitory concentrations of 5-FU or DOXO in cardiocytes and colon cancer cells. We have found that the treatment with 400 μM 5-FU induced apoptosis in 32% of H9c2 cells. This effect was increased by the addition of LF to 5-FU (38% of apoptotic cells). Apoptosis occurred in only about 10% of HT-29 cells treated with either 5-FU or 5-FU and LF in combination. DOXO induced poor effects on apoptosis of both H9c2 and HT-29 cells (5–7% apoptotic cells, respectively). The apoptosis induced by 5-FU and LF in cardiocytes was paralleled by the activation of caspases 3, 9 and 7 and by the intracellular increase of O²⁻ levels.

Conclusions

These results suggest that cardiotoxic mechanism of chemotherapy agents are different and this disclose a new scenario for prevention of this complication.

Protective effects of nebivolol against anthracycline-induced cardiomyopathy: a randomized control study

BACKGROUND

We aimed to evaluate the effect of prophylactic nebivolol use on prevention of antracycline-induced cardiotoxicity in breast cancer patients.

METHODS

In this small, prospective, double-blind study, we randomly assigned 45 consecutive patients with breast cancer and planned chemotheraphy to receive nebivolol 5mg daily (n=27) or placebo (n=18). Echocardiographic measurements and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) levels were obtained at baseline and at 6-month of chemotherapy.

RESULTS

Both studied groups had comparable echocardiographic variables and NT-pro-BNP levels at baseline. At 6-month, the left ventricular (LV) end-systolic and end-diastolic diameters increased in the placebo group (LVESD: 29.7 ± 3.4 to 33.4 ± 4.5mm; LVEDD: 47.2 ± 3.8 to 52.0 ± 4.6mm, p=0.01 for both) but remained unchanged in the nebivolol group (LVESD: 30.4 ± 3.5 to 31.0 ± 3.6mm, p=0.20; LVEDD: 47.0 ± 4.4 to 47.1 ± 4.0mm, p=0.93). The placebo group also had lower LVEF than the nebivolol group (57.5 ± 5.6% vs. 63.8 ± 3.9%, p=0.01) at 6-month. NT-pro-BNP level remained static in the nebivolol group (147 ± 57 to 152 ± 69 pmol/l, p=0.77) while it increased in the placebo group (144 ± 66 to 204 ± 73 pmol/l, p=0.01).

CONCLUSIONS

Prophylactic use of nebivolol treatment may protect the myocardium against antracycline-induced cardiotoxicity in breast cancer patients.

Microfluidic fabrication of cationic curcumin nanoparticles as an anti-cancer agent

Curcumin nanoparticles of less than 50 nm in diameter are accessible using a continuous flow microfluidic rotating tube processor (RTP) under scalable conditions, at room temperature. A mixture of DDAB and Pluronic F127 renders higher stability of the curcumin nanoparticles in physiological pH 7.4 for up to eight hours. The nanoparticles have enhanced cytotoxicity in estrogens receptor negative and positive breast cancer cell lines compared with free curcumin.

Angina Pectoris und ST-Hebungen nach Chemotherapie mit 5-FU

We report on the case of a 64 year old male who received chemotherapy for a metastatic squamous cell carcinoma of the oropharynx. The chemotherapeutic regimen consisted of 5-fluorouracil (5-FU) and cisplatin. Six hours after completion of the first 24 h continuous infusion of 5-FU, the patient developed severe chest pain accompanied by vegetative symptoms and a pronounced ST-elevation of the precordial leads. Under the suspicion of an acute anterior myocardial infarction an immediate coronary angiogram was performed, demonstrating a total occlusion of the left anterior descending (LAD) coronary artery close to the left main stem. The other coronary arteries appeared smooth. After the intracoronary administration of nitroglycerine, the LAD reopened spontaneously without any residual stenosis, paralleled by complete relief of all symptoms. Therefore, 5-FU induced coronary spasm was diagnosed. After initial therapy with intravenous nitrate followed by oral calcium channel blocker, the patient remained free of symptoms and no rise in cardiac enzymes were noted. The chemotherapeutic regimen was changed to cisplatin plus docetaxel. No new attacks of chest pain occurred and the antivasospastic therapy could be stopped without further events.

Coronary artery spasm induced by 5-fluorouracil

The frequently used chemotherapeutic drug 5-fluorouracil (5-FU) is known to cause angina pectoris and arrhythmias; myocardial infarction and sudden cardiac death could occur. Potential reasons for these phenomena range from toxic/metabolic disturbances to coronary artery spasms. This report shows angiographically proven spasmophilia of the coronary arteries and contributes to the understanding of angina pectoris occurring during treatment with 5-FU. Thus, verapamil type calcium antagonists as well as nitrates should be administered primarily in patients with coronary artery disease and in all patients who had been symptomatic during 5-FU administration in order to prevent further episodes.

Cardiotoxicity of cytotoxic drugs

Cardiotoxicity is a well-known side effect of several cytotoxic drugs, especially of the anthracyclines and can lead to long term morbidity. The mechanism of anthracycline induced cardiotoxicity seems to involve the formation of free radicals leading to oxidative stress. This may cause apoptosis of cardiac cells or immunologic reactions. However, alternative mechanisms may play a role in anthracycline induced cardiotoxicity. Cardiac protection can be achieved by limitation of the cumulative dose. Furthermore, addition of the antioxidant and iron chelator dexrazoxane to anthracycline therapy has shown to be effective in lowering the incidence of anthracycline induced cardiotoxicity. Other cytotoxic drugs such as 5-fluorouracil, cyclophosphamide and the taxoids are associated with cardiotoxicity as well, although little is known about the possible mechanisms. Recently, it appeared that some novel cytotoxic drugs such as trastuzumab and cyclopentenyl cytosine also show cardiotoxic side effects.

Physical training during intrahepatic chemotherapy

OBJECTIVE

To evaluate the role of strength and endurance training for the muscular, cardiac, respiratory, and immune systems and the quality of life (QOL) during intrahepatic chemotherapy (folinic acid, 5-fluorouracil).

DESIGN

Single case.

SETTING

Teaching hospital in Germany.

PARTICIPANT

An elderly athlete with liver metastasis after resection of a carcinoma of the rectum (pT3, N0, M-liver, G2).

INTERVENTION

Strength and endurance training during chemotherapy.

MAIN OUTCOME MEASURES

During the intervals between training cycles (14d), beginning in postoperative week 6, a strength and endurance training regimen was performed twice weekly for 13 weeks, with an intensity of 40% to 60% of the maximum postoperative individual power and endurance. Before and after chemotherapy, we checked echocardiograms, resting and exercise electrocardiograms, lung function, natural killer (NK) cells, and the Gastrointestinal Quality of Life Index (GIQLI) scores.

RESULTS

The increase in strength was between 0% and 144%. The improvement in endurance expressed by reduction of heart rate and lactate concentration was 10% and 21.5%, respectively. Lung function also improved with regard to forced expiratory volume in 1 second (12.9%), forced vital capacity (11.3%), and inspiratory vital capacity (11.4%). The relative count of the NK cells increased to 27.2%. An improvement in the GIQLI was observed from 109 points (pathologic) to 129 points.

CONCLUSION

Strength and endurance training was associated with an increase of physical strength and endurance with positive influence on illness-related QOL. Postoperative physical exercise during regional chemotherapy is beneficial.

[Emergency coronary angioplasty following treatment with 5-fluorouracil]

INTRODUCTION

The incidence of cardiac toxicity due to 5-fluorouracil (5-FU) ranges from 1.2 to 18%. Most complications occur at the time of the first cure. Their mechanisms have not yet been clearly defined.

EXEGESIS

The authors report a case of unstable angina induced by 5-FU. A coronary angioplasty was performed on a previously ignored coronary lesion.

CONCLUSION

Recent studies support the hypothesis that 5-FU has endothelial toxicity resulting in thrombogenic effect and release of vasoactive substances. Unstable angina pectoris would be related to plaque rupture caused by 5-FU. Patients with previous history of coronary disease are at significantly increased risk for 5-FU-induced cardiotoxicity. They probably would benefit from continuous electrocardiographic monitoring. Rechallenge with 5-FU after cardiotoxicity problems should include only those patients for whom there is no alternative treatment.

Cardiotoxicity of the antiproliferative compound fluorouracil

The antimetabolite fluorouracil (5-FU) is frequently administered for chemotherapy of various malignant neoplasms. The drug is well known for its adverse effects involving bone marrow, skin, mucous membranes, intestinal tract and central nervous system, whereas its cardiotoxicity is less familiar to clinicians. The pathophysiology of fluorouracil-associated cardiac adverse events is controversial and conclusions are based on clinical studies and case reports more than on solid experimental evidence. While clinical and electrocardiographic features suggest myocardial ischaemia as a main aetiological factor, possibly induced by coronary vasospasm, histomorphological and biochemical studies indicate a more direct drug-mediated cytotoxic action. Estimates of the overall incidence of fluorouracil cardiotoxicity have varied widely from 1.2 to 18% of patients. Patients may present with angina-like chest pain, cardiac arrhythmias or myocardial infarction. There is no unequivocally effective prophylaxis or treatment in this syndrome. Once fluorouracil administration is discontinued symptoms are usually reversible, although fatal events have been described. The overall mortality rate has been estimated to be between 2.2 and 13.3%. There is a high risk of relapse when patients are re-exposed to this drug following previous cardiac incidents. From the present data it is concluded that cardiotoxicity is a relevant but underestimated problem in fluorouracil treatment. Since the mechanisms of fluorouracil-associated cardiotoxicity are not yet fully understood, all patients undergoing this chemotherapy have to be carefully evaluated and monitored for cardiac risk factors and complaints. After cardiotoxic events, fluorouracil should definitely be withdrawn and replaced by an alternative antiproliferative regimen.