Search Results (21)

Objective: Radiotherapy administered to control thoracic cancers results in a partial irradiation of the heart at mean doses up to 19 Gy, which increases the risk of developing a spectrum of cardiovascular diseases known as radiation-induced heart disease (RIHD). As inflammation is a major driver of the development of RIHD, we investigated the potential of the anti-inflammatory agent cannabidiol (CBD) to attenuate irradiation-induced cardiovascular damage in vivo. Methods: Female C57BL/6 mice were given daily injections of CBD (i.p., 20 mg/kg body weight) for 4 weeks beginning either 2 weeks prior to 16 Gy irradiation of the heart or at the time of irradiation. Mice were sacrificed 30 min and 2, 4, and 10 weeks after irradiation to investigate the expression of inflammatory markers and stress proteins in primary cardiac endothelial cells (ECs). DNA double-strand breaks, immune cell infiltration, and signs of fibrosis were studied in explanted heart tissue. Results: We showed that the irradiation-induced upregulation of the inflammatory markers ICAM-1 and MCAM was only attenuated when treatment with CBD was started 2 weeks prior to irradiation but not when the CBD treatment was started concomitant with irradiation of the heart. The protective effect of CBD was associated with a decrease in irradiation-induced DNA damage and an increased expression of protective heat shock proteins (Hsp), such as Hsp32/Heme-oxygenase-1 (HO-1) and Hsp70, in the heart tissue. While the upregulation of the inflammatory markers ICAM-1 and MCAM, expression was prevented up to 10 weeks after irradiation by CBD pre-treatment, and the expression of VCAM-1, which started to increase 10 weeks after irradiation, was further upregulated in CBD pre-treated mice. Despite this finding, 10 weeks after heart irradiation, immune cell infiltration and fibrosis markers of the heart were significantly reduced in CBD pre-treated mice. Conclusion: CBD treatment before irradiation mediates beneficial effects on murine hearts of mice, resulting in a reduction of radiation-induced complications, such as vascular inflammation, immune cell infiltration, and fibrosis. Full article

Radiation therapy (RT) is widely used to treat thoracic cancers but carries a risk of radiation-induced heart disease (RIHD). This study aimed to detect early markers of RIHD using machine learning (ML) techniques and cardiac MRI in a rat model. SS.BN3 consomic rats, which have a more subtle RIHD phenotype compared to Dahl salt-sensitive (SS) rats, were treated with localized cardiac RT or sham at 10 weeks of age. Cardiac MRI was performed 8 and 10 weeks post-treatment to assess global and regional cardiac function. ML algorithms were applied to differentiate sham-treated and irradiated rats based on early changes in myocardial function. Despite normal global left ventricular ejection fraction in both groups, strain analysis showed significant reductions in the anteroseptal and anterolateral segments of irradiated rats. Gradient boosting achieved an F1 score of 0.94 and an ROC value of 0.95, while random forest showed an accuracy of 88%. These findings suggest that ML, combined with cardiac MRI, can effectively detect early preclinical changes in RIHD, particularly alterations in regional myocardial contractility, highlighting the potential of these techniques for early detection and monitoring of radiation-induced cardiac dysfunction. Full article

Objective: Radiotherapy, which is commonly used for the local control of thoracic cancers, also induces chronic inflammatory responses in the microvasculature of surrounding normal tissues such as the lung and heart that contribute to fatal radiation-induced lung diseases (RILDs) such as pneumonitis and fibrosis. In this study, we investigated the potential of cannabidiol (CBD) to attenuate the irradiation damage to the vasculature. Methods: We investigated the ability of CBD to protect a murine endothelial cell (EC) line (H5V) and primary lung ECs isolated from C57BL/6 mice from irradiation-induced damage in vitro and lung ECs (luECs) in vivo, by measuring the induction of oxidative stress, DNA damage, apoptosis (in vitro), and induction of inflammatory and pro-angiogenic markers (in vivo). Results: We demonstrated that a non-lethal dose of CBD reduces the irradiation-induced oxidative stress and early apoptosis of lung ECs by upregulating the expression of the cytoprotective mediator heme-oxygenase-1 (HO-1). The radiation-induced increased expression of inflammatory (ICAM-2, MCAM) and pro-angiogenic (VE-cadherin, Endoglin) markers was significantly reduced by a continuous daily treatment of C57BL/6 mice with CBD (i.p. 20 mg/kg body weight), 2 weeks before and 2 weeks after a partial irradiation of the lung (less than 20% of the lung volume) with 16 Gy. Conclusions: CBD has the potential to improve the clinical outcome of radiotherapy by reducing toxic side effects on the microvasculature of the lung. Full article

Recent epidemiological studies have shown that patients with right-sided breast cancer (RBC) treated with X-ray irradiation (IR) are more susceptible to developing cardiovascular diseases, such as arrhythmias, atrial fibrillation, and conduction disturbances after radiotherapy (RT). Our aim was to investigate the mechanisms induced by low to moderate doses of IR and to evaluate changes in the cardiac sympathetic nervous system (CSNS), atrial remodeling, and calcium homeostasis involved in cardiac rhythm. To mimic the RT of the RBC, female C57Bl/6J mice were exposed to X-ray doses ranging from 0.25 to 2 Gy targeting 40% of the top of the heart. At 60 weeks after RI, Doppler ultrasound showed a significant reduction in myocardial strain, ejection fraction, and atrial function, with a significant accumulation of fibrosis in the epicardial layer and apoptosis at 0.5 mGy. Calcium transient protein expression levels, such as RYR2, NAK, Kir2.1, and SERCA2a, increased in the atrium only at 0.5 Gy and 2 Gy at 24 h, and persisted over time. Interestingly, 3D imaging of the cleaned hearts showed an early reduction of CSNS spines and dendrites in the ventricles and a late reorientation of nerve fibers, combined with a decrease in SEMA3a expression levels. Our results showed that local heart IR from 0.25 Gy induced late cardiac and atrial dysfunction and fibrosis development. After IR, ventricular CSNS and calcium transient protein expression levels were rearranged, which affected cardiac contractility. The results are very promising in terms of identifying pro-arrhythmic mechanisms and preventing arrhythmias during RT treatment in patients with RBC. Full article

Radiation-induced heart disease (RIHD), a common side effect of chest irradiation, is a primary cause of mortality among patients surviving thoracic cancer. Thus, the development of novel, clinically applicable cardioprotective agents which can alleviate the harmful effects of irradiation on the heart is of great importance in the field of experimental oncocardiology. Biglycan and decorin are structurally related small leucine-rich proteoglycans which have been reported to exert cardioprotective properties in certain cardiovascular pathologies. Therefore, in the present study we aimed to examine if biglycan or decorin can reduce radiation-induced damage of cardiomyocytes. A single dose of 10 Gray irradiation was applied to induce radiation-induced cell damage in H9c2 cardiomyoblasts, followed by treatment with either biglycan or decorin at various concentrations. Measurement of cell viability revealed that both proteoglycans improved the survival of cardiac cells post-irradiation. The cardiocytoprotective effect of both biglycan and decorin involved the alleviation of radiation-induced proapoptotic mechanisms by retaining the progression of apoptotic membrane blebbing and lowering the number of apoptotic cell nuclei and DNA double-strand breaks. Our findings provide evidence that these natural proteoglycans may exert protection against radiation-induced damage of cardiac cells. Full article

Radiotherapy-induced cardiac toxicity and consequent diseases still represent potential severe late complications for many cancer survivors who undergo therapeutic thoracic irradiation. We aimed to assess the phenotypic and paracrine features of resident cardiac mesenchymal stromal cells (CMSCs) at early follow-up after the end of thoracic irradiation of the heart as an early sign and/or mechanism of cardiac toxicity anticipating late organ dysfunction. Resident CMSCs were isolated from a rat model of fractionated thoracic irradiation with accurate and clinically relevant heart dosimetry that developed delayed dose-dependent cardiac dysfunction after 1 year. Cells were isolated 6 and 12 weeks after the end of radiotherapy and fully characterized at the transcriptional, paracrine, and functional levels. CMSCs displayed several altered features in a dose- and time-dependent trend, with the most impaired characteristics observed in those exposed in situ to the highest radiation dose with time. In particular, altered features included impaired cell migration and 3D growth and a and significant association of transcriptomic data with GO terms related to altered cytokine and growth factor signaling. Indeed, the altered paracrine profile of CMSCs derived from the group at the highest dose at the 12-week follow-up gave significantly reduced angiogenic support to endothelial cells and polarized macrophages toward a pro-inflammatory profile. Data collected in a clinically relevant rat model of heart irradiation simulating thoracic radiotherapy suggest that early paracrine and transcriptional alterations of the cardiac stroma may represent a dose- and time-dependent biological substrate for the delayed cardiac dysfunction phenotype observed in vivo. Full article

Cardio-oncology currently faces one of the greatest challenges in the field of health care. The main goal of this discipline is to ensure that patients treated for cancer do not suffer or die from cardiovascular disease. The number of studies on the mechanisms of heart injury during cancer treatment is constantly increasing. However, there is insufficient data on heart rhythm disorders that may result from this treatment. This issue seems to be particularly important in patients with lung cancer, in whom anticancer therapy, especially radiotherapy, may contribute to the onset of cardiac arrhythmias. The observed relationship between cardiac dosimetry and radiotherapy-induced cardiotoxicity in lung cancer treatment may explain the increased mortality from cardiovascular causes in patients after chest irradiation. Further research is essential to elucidate the role of cardiac arrhythmias in this context. Conversely, recent reports have highlighted the application of stereotactic arrhythmia radioablation (STAR) in the treatment of ventricular tachycardia. This review of available studies on the epidemiology, pathogenesis, diagnosis, and treatment of arrhythmias in patients treated for lung cancer aims to draw attention to the need for regular cardiological monitoring in this group of patients. Improving cardiac care for patients with lung cancer has the potential to enhance their overall therapeutic outcomes. Full article

Background: Major improvements in cancer therapies have significantly contributed to increased survival rates of Hodgkin lymphoma (HL) survivors, outweighing cardiovascular side effects and the risks of radiation-induced heart disease. Non-invasive screening for coronary artery disease (CAD) starting five years after irradiation is recommended, as plaque development and morphology may differ in this high-risk population. Due to rapid plaque progression and a possibly higher incidence of non-calcified plaques, coronary artery calcium scoring may not be sufficient as a screening modality in HL survivors treated with thoracic radiotherapy. Case summary: A 42-year-old man with a history of HL treated with thoracic radiotherapy presented at the emergency department 20 years after cancer treatment with an ST-elevation myocardial infarction, in the absence of cardiovascular risk factors, for which primary percutaneous coronary intervention of the left anterior descending artery was performed. Four months prior to acute myocardial infarction, invasive coronary angiography only showed wall irregularities. Two years earlier, the Agatston calcium score was zero. Discussion: In HL survivors treated with thoracic radiotherapy, a calcium score of zero may not give the same warranty period for cardiac event-free survival compared to the general population. Coronary computed tomography angiography can be a proper diagnostic tool to detect CAD at an early stage after mediastinal irradiation, as performing calcium scoring may not be sufficient in this population to detect non-calcified plaques, which may show rapid progression and lead to acute coronary syndrome. Also, intensive lipid-lowering therapy should be considered in the presence of atherosclerosis in this patient population. Full article

Recent epidemiologic studies support an association between chronic low-dose radiation exposure and the development of cardiovascular disease (CVD). The molecular mechanisms underlying the adverse effect of chronic low dose exposure are not fully understood. To address this issue, we have investigated changes in the heart proteome of ApoE deficient (ApoE^−/−) C57Bl/6 female mice chronically irradiated for 300 days at a very low dose rate (1 mGy/day) or at a low dose rate (20 mGy/day), resulting in cumulative whole-body doses of 0.3 Gy or 6.0 Gy, respectively. The heart proteomes were compared to those of age-matched sham-irradiated ApoE^−/− mice using label-free quantitative proteomics. Radiation-induced proteome changes were further validated using immunoblotting, enzyme activity assays, immunohistochemistry or targeted transcriptomics. The analyses showed persistent alterations in the cardiac proteome at both dose rates; however, the effect was more pronounced following higher dose rates. The altered proteins were involved in cardiac energy metabolism, ECM remodelling, oxidative stress, and ageing signalling pathways. The changes in PPARα, SIRT, AMPK, and mTOR signalling pathways were found at both dose rates and in a dose-dependent manner, whereas more changes in glycolysis and ECM remodelling were detected at the lower dose rate. These data provide strong evidence for the possible risk of cardiac injury following chronic low dose irradiation and show that several affected pathways following chronic irradiation overlap with those of ageing-associated heart pathology. Full article

The heart is one of the organs that is sensitive to developing delayed adverse effects of ionizing radiation (IR) exposure. Radiation-induced heart disease (RIHD) occurs in cancer patients and cancer survivors, as a side effect of radiation therapy of the chest, with manifestation several years post-radiotherapy. Moreover, the continued threat of nuclear bombs or terrorist attacks puts deployed military service members at risk of exposure to total or partial body irradiation. Individuals who survive acute injury from IR will experience delayed adverse effects that include fibrosis and chronic dysfunction of organ systems such as the heart within months to years after radiation exposure. Toll-like receptor 4 (TLR4) is an innate immune receptor that is implicated in several cardiovascular diseases. Studies in preclinical models have established the role of TLR4 as a driver of inflammation and associated cardiac fibrosis and dysfunction using transgenic models. This review explores the relevance of the TLR4 signaling pathway in radiation-induced inflammation and oxidative stress in acute as well as late effects on the heart tissue and the potential for the development of TLR4 inhibitors as a therapeutic target to treat or alleviate RIHD. Full article

Survivors of acute radiation exposure are likely to experience delayed effects that manifest as injury in late-responding organs such as the heart. Non-invasive indicators of radiation-induced cardiac dysfunction are important in the prediction and diagnosis of this disease. In this study, we aimed to identify urinary metabolites indicative of radiation-induced cardiac damage by analyzing previously collected urine samples from a published study. The samples were collected from male and female wild-type (C57BL/6N) and transgenic mice constitutively expressing activated protein C (APCHi), a circulating protein with potential cardiac protective properties, who were exposed to 9.5 Gy of γ-rays. We utilized LC-MS-based metabolomics and lipidomics for the analysis of urine samples collected at 24 h, 1 week, 1 month, 3 months, and 6 months post-irradiation. Radiation caused perturbations in the TCA cycle, glycosphingolipid metabolism, fatty acid oxidation, purine catabolism, and amino acid metabolites, which were more prominent in the wild-type (WT) mice compared to the APCHi mice, suggesting a differential response between the two genotypes. After combining the genotypes and sexes, we identified a multi-analyte urinary panel at early post-irradiation time points that predicted heart dysfunction using a logistic regression model with a discovery validation study design. These studies demonstrate the utility of a molecular phenotyping approach to develop a urinary biomarker panel predictive of the delayed effects of ionizing radia-tion. It is important to note that no live mice were used or assessed in this study; instead, we focused solely on analyzing previously collected urine samples. Full article

In radiation therapy of tumors in the chest, such as in lung or esophageal cancer, part of the heart may be situated in the radiation field. This can lead to the development of radiation-induced heart disease. The mechanisms by which radiation causes long-term injury to the heart are not fully understood, but investigations in pre-clinical research models can contribute to mechanistic insights. Recent developments in X-ray technology have enabled partial heart irradiation in mouse models. In this study, adult male and female C57BL/6J mice were exposed to whole heart (a single dose of 8 or 16 Gy) and partial heart irradiation (16 Gy to 40% of the heart). Plasma samples were collected at 5 days and 2 weeks after the irradiation for metabolomics analysis, and the cardiac collagen deposition, mast cell numbers, and left ventricular expression of Toll-like receptor 4 (TLR4) were examined in the irradiated and unirradiated parts of the heart at 6 months after the irradiation. Small differences were found in the plasma metabolite profiles between the groups. However, the collagen deposition did not differ between the irradiated and unirradiated parts of the heart, and radiation did not upregulate the mast cell numbers in either part of the heart. Lastly, an increase in the expression of TLR4 was seen only after a single dose of 8 Gy to the whole heart. These results suggest that adverse tissue remodeling was not different between the irradiated and unirradiated portions of the mouse heart. While there were no clear differences between male and female animals, additional work in larger cohorts may be required to confirm this result, and to test the inhibition of TLR4 as an intervention strategy in radiation-induced heart disease. Full article

Radiation-Induced CardioVascular Disease (RICVD) is an important concern in thoracic radiotherapy with complex underlying pathophysiology. Recently, we proposed DNA methylation as a possible mechanism contributing to RICVD. The current study investigates DNA methylation in heart-irradiated rats and radiotherapy-treated breast cancer (BC) patients. Rats received fractionated whole heart X-irradiation (0, 0.92, 6.9 and 27.6 Gy total doses) and blood was collected after 1.5, 3, 7 and 12 months. Global and gene-specific methylation of the samples were evaluated; and gene expression of selected differentially methylated regions (DMRs) was validated in rat and BC patient blood. In rats receiving an absorbed dose of 27.6 Gy, DNA methylation alterations were detected up to 7 months with differential expression of cardiac-relevant DMRs. Of those, SLMAP showed increased expression at 1.5 months, which correlated with hypomethylation. Furthermore, E2F6 inversely correlated with a decreased global longitudinal strain. In BC patients, E2F6 and SLMAP exhibited differential expression directly and 6 months after radiotherapy, respectively. This study describes a systemic radiation fingerprint at the DNA methylation level, elucidating a possible association of DNA methylation to RICVD pathophysiology, to be validated in future mechanistic studies. Full article

Recent reports have shown a link between radiation exposure and non-cancer diseases such as radiation-induced heart disease (RIHD). Radiation exposures are often inhomogeneous, and out-of-target effects have been studied in terms of cancer risk, but very few studies have been carried out for non-cancer diseases. Here, the role of miRNAs in the pathogenesis of RIHD was investigated. C57Bl/6J female mice were whole- (WBI) or partial-body-irradiated (PBI) with 2 Gy of X-rays or sham-irradiated (SI). In PBI exposure, the lower third of the mouse body was irradiated, while the upper two-thirds were shielded. From all groups, hearts were collected 15 days or 6 months post-irradiation. The MiRNome analysis at 15 days post-irradiation showed that miRNAs, belonging to the myomiR family, were highly differentially expressed in WBI and PBI mouse hearts compared with SI hearts. Raman spectral data collected 15 days and 6 months post-irradiation showed biochemical differences among SI, WBI and PBI mouse hearts. Fibrosis in WBI and PBI mouse hearts, indicated by the increased deposition of collagen and the overexpression of genes involved in myofibroblast activation, was found 6 months post-irradiation. Using an in vitro co-culture system, involving directly irradiated skeletal muscle and unirradiated ventricular cardiac human cells, we propose the role of miR-1/133a as mediators of the abscopal response, suggesting that miRNA-based strategies could be relevant for limiting tissue-dependent reactions in non-directly irradiated tissues. Full article

Radiation-induced cardiovascular disease is associated with metabolic remodeling in the heart, mainly due to the inactivation of the transcription factor peroxisome proliferator-activated receptor alpha (PPARα), thereby inhibiting lipid metabolic enzymes. The objective of the present study was to investigate the potential protective effect of fenofibrate, a known agonist of PPARα on radiation-induced cardiac toxicity. To this end, we compared, for the first time, the cardiac proteome of fenofibrate- and placebo-treated mice 20 weeks after local heart irradiation (16 Gy) using label-free proteomics. The observations were further validated using immunoblotting, enzyme activity assays, and ELISA. The analysis showed that fenofibrate restored signalling pathways that were negatively affected by irradiation, including lipid metabolism, mitochondrial respiratory chain, redox response, tissue homeostasis, endothelial NO signalling and the inflammatory status. The results presented here indicate that PPARα activation by fenofibrate attenuates the cardiac proteome alterations induced by irradiation. These findings suggest a potential benefit of fenofibrate administration in the prevention of cardiovascular diseases, following radiation exposure. Full article