Pathomechanisms and therapeutic opportunities in radiation-induced heart disease: from bench to bedside

Radiation-Induced Coronary Artery Disease in Lung and Breast Cancer Patients: Insights from PET Imaging and Long-Term Risk Assessment

Radiation-induced coronary artery disease (RI-CAD) is a significant cardiovascular complication for cancer survivors treated with thoracic radiation therapy (RT). Despite advances in RT techniques, exposure to the heart during treatment remains a critical factor influencing long-term cardiac outcomes, particularly in patients with breast and lung cancer. RI-CAD develops due to radiation-induced endothelial injury, inflammation, and accelerated atherosclerosis, presenting a unique and aggressive disease profile. This review explores the pathophysiology, risk factors, and diagnostic advancements for RI-CAD, emphasizing the role of PET in improving patient outcomes.

Quantitative evaluation of radiation-induced heart disease in beagle dogs by speckle tracking echocardiography

OBJECTIVE

This study aimed to detect early changes in left ventricular systolic function in Beagle dogs after radiotherapy using two-dimensional speckle tracking echocardiography and to explore its potential value in evaluating radiation-induced heart disease.

METHODS

Thirty-six Beagle dogs were randomized into a control group (n = 18) and an irradiation group (n = 18). The irradiation group received a single dose of 20 Gy to the left ventricular anterior wall, while controls underwent sham irradiation. Conventional echocardiography and 2D speckle tracking echocardiography were performed at baseline and 3, 6, and 12 months post-procedure. Additionally, six dogs were randomly selected from each group and euthanized at 3-, 6-, and 12-month post-irradiation, and their hearts were collected for histopathological testing.

RESULTS

In the irradiation group, the global longitudinal strain of the left ventricle and regional strain in the irradiated area were significantly reduced versus baseline and controls by 3 months, with progressive decline at 6 and 12 months. Strain reduction correlated spatially with pathological injury. Conversely, there were no substantial differences in conventional echocardiographic parameters between the groups after 3 months. Conventional parameters (e.g., LVEF) showed differences only at later timepoints. Histopathology revealed progressive cardiomyocyte damage, fibrosis, and microvascular injury in irradiated regions, extending to the posterior wall by 12 months.

CONCLUSION

Two-dimensional speckle tracking echocardiography-derived strain parameters spatially correlate with radiation-induced pathological changes and detect subtle systolic dysfunction prior to irreversible remodeling. Speckle tracking may localize regions of peak radiation dose delivery.

Elucidating the mechanism of action of astragalus polysaccharide on ionizing radiation-induced myocardial damage based on network pharmacology and experimental research

Due to the unavoidable impact of ionizing radiation on the heart located near the mediastinum, varying degrees of myocardial damage may occur. As a result, the clinical application of radiotherapy in cancer treatment is significantly limited. However, the molecular mechanisms underlying radiation-induced heart disease (RIHD) are not yet fully understood, and there is a lack of disease-specific treatment strategies. Astragalus polysaccharide (APS), is an active compound abundant in the traditional Chinese herb Astragalus membranaceus (Fisch.) Bunge (AS), has been shown to have cardioprotective effects against various cardiovascular diseases. Thus, this study aims to investigate the potential cardioprotective effect of APS on RIHD and its underlying molecular mechanisms. The network pharmacology results indicated that 9 core genes were identified from the biological network of the effective components of AS acting on RIHD. The results of GO enrichment analysis showed that these hub genes were mainly involved in biological processes such as cell apoptosis, cell proliferation, inflammatory response, and response to external stimuli. The results of KEGG enrichment analysis showed that these hub genes mainly regulated the occurrence of RIHD through pathways such as the EGFR signaling pathway, PI3K/Akt signaling pathway, IL-17 signaling pathway, and so on. In molecular docking analysis, we found that AKT1 and mTOR had good and stable binding abilities with the three types of glucosides rich in AS. The results of in vitro and in vivo experiments all showed that APS could not only improve cardiac dysfunction, myocardial injury, inflammatory response, and myocardial fibrosis in RIHD rats, but also alleviated apoptosis and atrophy of H9C2 cells under ionizing radiation stimulation. In addition, we also found that APS improved the accumulation of autophagic flux induced by ionizing radiation, which could be confirmed by the reversal of Beclin1, p62, LC3B proteins and accelerated degradation of accumulated autophagic vesicles. Rapamycin (Rap) was a classic autophagy flux inducer that could attenuate the improvement effect of APS on H9C2 cell apoptosis under ionizing radiation stimulation. Finally, we found that APS could reverse the inhibition of PI3K/Akt/mTOR signaling pathway activity by ionizing radiation in vitro, thereby improving ionizing radiation-induced autophagy flux accumulation, cardiomyocyte apoptosis, and atrophy. All in all, this study provides important evidence for understanding the molecular mechanisms of the cross-talk between autophagy and apoptosis, and provides new directions and insights for APS combined with autophagy regulators as a therapeutic strategy for RIHD.

Mechanistic Insights and Knowledge Gaps in the Effects of Radiation Therapy on Cardiac Arrhythmias

Stereotactic body radiation therapy (SBRT) is an innovative modality for the treatment of refractory ventricular arrhythmias (VAs). Phase 1/2 clinical trials have demonstrated the remarkable efficacy of SBRT at reducing VA burden (by >85%) in patients with good short-term safety. SBRT as an option for VA treatment delivered in an ambulatory nonsedated patient in a single fraction during an outpatient session of 15 to 30 minutes, without added risks of anesthetic or surgery, is clinically relevant. However, the underlying mechanism remains unclear. Currently, the clinical dosing of SBRT has been derived from preclinical studies aimed at inducing transmural fibrosis in the atria. The propitious clinical effects of SBRT appear earlier than the time course for fibrosis. This review addresses the plausible mechanisms by which radiation alters the electrophysiological properties of myocytes and myocardial conduction to impart an antiarrhythmic effect, elucidate clinical observations, and point the direction for further research in this promising area.

Quantitative evaluation of radiation-induced heart disease in patients with lung cancer: a three-dimensional speckle tracking imaging study

Background

Adverse cardiovascular events due to radiation-induced heart disease (RIHD) have become the leading cause of death in cancer survivors, and early screening for RIHD has become an important clinical issue. Our objective was to determine the utility of three-dimensional speckle tracking echocardiography (3D-STE) for detecting RIHD.

Methods

According to inclusion and exclusion criteria, patients with lung cancer who received radiotherapy in our hospital for the first time were recruited as subjects. All subjects underwent the conventional echocardiography and 3D-STE examination at six time points (1 day before radiotherapy, 2.5-3 and 5-6 weeks after beginning radiotherapy, and 3-, 6- and 12-month after ending radiotherapy). Routine electrocardiogram, serum cardiac troponin I (cTnI) and clinical data were detected simultaneously.

Results

A total of 105 patients with lung cancer were included in the study. Conventional echocardiography found a small amount of pericardial effusion occurred in 8 subjects at 5-6 weeks after beginning radiotherapy. 3D-STE showed that, compared with before radiotherapy, the absolute values of global longitudinal strain (GLS) and global strain (GS) were significantly decreased at 5-6 weeks after beginning radiotherapy (PGLS<0.001, PGS=0.002), and the absolute values of GLS, global radial strain, global circumferential strain, GS were gradually decreased further at 3-, 6- and 12-month after ending radiotherapy (P<0.001). Electrocardiograph showed that 32 subjects had electrocardiograph abnormalities during radiotherapy and 3 had electrocardiograph abnormalities at 3-month after ending radiotherapy, and most returned to normal within 6 months after ending radiotherapy.

Conclusions

Patients with lung cancer undergoing radiation therapy have shown a decrease in the function of the left ventricle of the heart while receiving treatment. Combining the assessment of cTnI with GLS can enhance the early detection of radiation-induced heart damage.

Copper homeostasis and cuproptosis in radiation-induced injury

Radiation therapy for cancer treatment brings about a series of radiation injuries to normal tissues. In recent years, the discovery of copper-regulated cell death, cuproptosis, a novel form of programmed cell death, has attracted widespread attention and exploration in various biological functions and pathological mechanisms of copper metabolism and cuproptosis. Understanding its role in the process of radiation injury may open up new avenues and directions for exploration in radiation biology and radiation oncology, thereby improving tumor response and mitigating adverse reactions to radiotherapy. This review provides an overview of copper metabolism, the characteristics of cuproptosis, and their potential regulatory mechanisms in radiation injury.

Dexmedetomidine ameliorates x-ray-induced myocardial injury via alleviating cardiomyocyte apoptosis and autophagy

BACKGROUND

Radiotherapy is a primary local treatment for tumors, yet it may lead to complications such as radiation-induced heart disease (RIHD). Currently, there is no standardized approach for preventing RIHD. Dexmedetomidine (Dex) is reported to have cardio-protection effects, while its role in radiation-induced myocardial injury is unknown. In the current study, we aimed to evaluate the radioprotective effect of dexmedetomidine in X-ray radiation-treated mice.

METHODS

18 male mice were randomized into 3 groups: control, 16 Gy, and 16 Gy + Dex. The 16 Gy group received a single dose of 16 Gy X-ray radiation. The 16 Gy + Dex group was pretreated with dexmedetomidine (30 µg/kg, intraperitoneal injection) 30 min before X-ray radiation. The control group was treated with saline and did not receive X-ray radiation. Myocardial tissues were collected 16 weeks after X-ray radiation. Hematoxylin-eosin staining was performed for histopathological examination. Terminal deoxynucleotidyl transferase dUTP nick-end labeling staining was performed to assess the state of apoptotic cells. Immunohistochemistry staining was performed to examine the expression of CD34 molecule and von Willebrand factor. Besides, western blot assay was employed for the detection of apoptosis-related proteins (BCL2 apoptosis regulator and BCL2-associated X) as well as autophagy-related proteins (microtubule-associated protein 1 light chain 3, beclin 1, and sequestosome 1).

RESULTS

The findings demonstrated that 16 Gy X-ray radiation resulted in significant changes in myocardial tissues, increased myocardial apoptosis, and activated autophagy. Pretreatment with dexmedetomidine significantly protects mice against 16 Gy X-ray radiation-induced myocardial injury by inhibiting apoptosis and autophagy.

CONCLUSION

In summary, our study confirmed the radioprotective effect of dexmedetomidine in mitigating cardiomyocyte apoptosis and autophagy induced by 16 Gy X-ray radiation.

Late coronary artery injury following chemoradiotherapy for thymic carcinoma: a case report

INTRODUCTION

Surgery remains the primary treatment modality for thymic carcinoma, with adjuvant radiotherapy being recommended to effectively mitigate local recurrence and metastasis rates subsequent to incomplete or complete resection. Chemoradiotherapy has the potential to induce coronary artery occlusion, thereby potentially impacting patients' long-term survival rates. The existing literature currently lacks comprehensive research on the lesion characteristics of coronary artery injury resulting from chemoradiotherapy.

CASE PRESENTATION

The male patient, aged 55, was admitted to the hospital due to recurrent chest tightness and pain persisting for one week. Notably, the patient had previously undergone curative resection surgery for thymic carcinoma seven years ago. After the surgical procedure, the patient underwent a course of adjuvant chemotherapy comprising docetaxel and platinum. 11 months later, imaging examination diagnosed tumor recurrence, and concurrent chemoradiotherapy was administered at a total dose of 62 Gy/31F for planning gross target volume (PGTV) and 54 Gy/31F for planning target volume (PTV) with 2 cycles of paclitaxel and cisplatin. Re-admission of the patient occurred after a 7-year interval subsequent to the completion of concurrent chemoradiotherapy, leading to a subsequent diagnosis of acute non-ST segment elevation myocardial infarction. Following administration of antiplatelet, anticoagulant, and anti-myocardial ischemia therapy, coronary angiography revealed the presence of a bifurcation lesion at the distal end of the left main trunk. Intravascular ultrasound (IVUS) examination demonstrated significant negative remodeling of both the main trunk and its branches at the bifurcation site, characterized by minimal atherosclerotic plaque components.

CONCLUSIONS

Chemoradiotherapy may induce damage to endothelial cells, resulting in an inflammatory response. Negative remodeling of blood vessels is likely to occur, primarily characterized by vasoconstriction but with less atherosclerotic plaque burden. Routine stent implantation in negatively remodeled areas may lead to vascular rupture, necessitating intravascular imaging examination.

The Proteoglycans Biglycan and Decorin Protect Cardiac Cells against Irradiation-Induced Cell Death by Inhibiting Apoptosis

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.

Approach to Lymphoma-Associated Cardiomyopathy

Cardiomyopathy is a disease of the myocardium that affects the heart structure and function, eventually resulting in heart failure, valvular regurgitation, arrhythmia, or even sudden cardiac death. Occurring following treatment of lymphoma, both Hodgkin's and Non-Hodgkin's, cardiomyopathy is a feared complication in these cancer survivors due to its significant association with morbidity and mortality. A review of the literature was conducted using a combination of keywords including "Cardiomyopathy," "Anthracycline," "Radiation," "Pathogenesis," and "Management." Anthracyclines and radiation are prominent entities explored in the discussion of lymphoma-associated cardiomyopathy, whereby the formation of reactive oxygen species following treatment with both has been seen in the pathogenesis. The current standard of care thus far for anthracycline-induced cardiomyopathy includes heart failure medications such as beta-blockers, angiotensin-converting enzyme inhibitors, aldosterone receptor antagonists, and loop-diuretics. On the other hand, radiation-induced cardiomyopathy management has not been well-established yet in literature, with agents such as antioxidants and anti-inflammatory drugs still being studied in rat models. The treatment approach to cardiotoxicity in a lymphoma patient should consist of a collaboration between the oncologist and cardiologist prior to lymphoma treatment initiation, to stratify the risk of development of cardiomyopathy in the patient, and decide the best chemotherapy or radiotherapy agent, dosing, and surveillance technique.

A multimodality assessment of the protective capacity of statin therapy in a mouse model of radiation cardiotoxicity

PURPOSE

Despite technological advances in radiotherapy (RT), cardiotoxicity remains a common complication in patients with lung, oesophageal and breast cancers. Statin therapy has been shown to have pleiotropic properties beyond its lipid-lowering effects. Previous murine models have shown statin therapy can reduce short-term functional effects of whole-heart irradiation. In this study, we assessed the efficacy of atorvastatin in protecting against the late effects of radiation exposure on systolic function, cardiac conduction, and atrial natriuretic peptide (ANP) following a clinically relevant partial-heart radiation exposure.

MATERIALS AND METHODS

Female, 12-week old, C57BL/6j mice received an image-guided 16 Gy X-ray field to the base of the heart using a small animal radiotherapy research platform (SARRP), with or without atorvastatin from 1 week prior to irradiation until the end of the experiment. The animals were followed for 50 weeks with longitudinal transthoracic echocardiography (TTE) and electrocardiography (ECG) every 10 weeks, and plasma ANP every 20 weeks.

RESULTS

At 30-50 weeks, mild left ventricular systolic function impairment observed in the RT control group was less apparent in animals receiving atorvastatin. ECG analysis demonstrated prolongation of components of cardiac conduction related to the heart base at 10 and 30 weeks in the RT control group but not in animals treated with atorvastatin. In contrast to systolic function, conduction disturbances resolved at later time-points with radiation alone. ANP reductions were lower in irradiated animals receiving atorvastatin at 30 and 50 weeks.

CONCLUSIONS

Atorvastatin prevents left ventricular systolic dysfunction, and the perturbation of cardiac conduction following partial heart irradiation. If confirmed in clinical studies, these data would support the use of statin therapy for cardioprotection during thoracic radiotherapy.

Cardiovascular Outcomes Associated With Exposure To Radiation Therapy In Thoracic Malignancies: An Insight Study Using the National Inpatient Database

Background Thoracic irradiation is a widely used therapeutic and palliative treatment option for thoracic neoplasms. However, short- and long-term cardiovascular adverse effects of radiation exposure remain a major concern. The short-term adverse effects are observed within months of exposure such as pericardial diseases; meanwhile, the long-term complications are usually insidious and manifest over decades, such as congestive heart failure, coronary artery disease, cardiomyopathy, conduction disorders, constrictive pericarditis, and valvular heart disease. Hence, long-term cardiovascular adverse effects are challenging to predict, and the association with radiation exposure remains difficult to establish. Methodology This retrospective, observational study was conducted using data from the National Inpatient Sample (NIS) database from 2016 to 2019. Adult patients with primary thoracic malignancies who underwent radiation therapy (RT) were defined using principal and secondary International Classification of Diseases, Tenth Revision codes. Other malignancies that can be treated with RT and all secondary malignancies were excluded from the primary comparison group. Cardiac outcomes were defined as the prevalence of congestive heart failure, coronary artery disease, cardiomyopathy, conduction disorders, pericardial diseases, and valvular heart diseases in the primary group. The multivariate logistic and the linear regression analyses were used to adjust for confounders. Results When compared to the general population, adults with thoracic malignancies exposed to RT had higher odds of developing chronic pericarditis (adjusted odds ratio (aOR) = 2, 95% confidence interval (CI) = 1.9-2.2, p < 0.001), acute pericarditis (aOR = 2.3, 95% CI = 1.9-2.9, p < 0.001), constrictive pericarditis (aOR = 2.8, 95% CI = 2.1-3.7, p < 0.001), conduction disorders (aOR = 1.3, 95% CI = 1.2-1.35, p < 0.001), coronary artery disease (aOR = 1.24, 95% CI = 1.2-1.27, p < 0.001), heart failure (aOR = 1.44, 95% CI = 1.4-1.5, p < 0.001), and valvular heart disease (aOR = 1.37, 95% CI = 1.3-1.4, p < 0.001). There was no difference in the odds of developing cardiac arrest (aOR = 1, 95% CI = 0.9-1.10, p = 0.6) or acute myocardial infarction (aOR = 1.1, 95% CI = 1-1.15, p < 0.001). When compared to adults with thoracic malignancies not exposed to RT, adults with thoracic malignancies who were exposed to RT had higher odds of developing acute myocardial infarction (aOR = 1.14, 95% CI = 1.1-1.18, p < 0.001), chronic pericarditis (aOR = 1.3, 95% CI = 1.2-1.3, p < 0.001), acute pericarditis (aOR = 1.6, 95% CI = 1.2-2.1, p < 0.001), constrictive pericarditis (aOR = 2.2, 95% CI = 1.5-3.2, p < 0.001), conduction disorders (aOR = 1.1, 95% CI = 1.08-1.13, p < 0.001), coronary artery disease (aOR = 1.14, 95% CI = 1.12-1.16, p < 0.001), heart failure (aOR = 1.2, 95% CI = 1.17-1.23, p < 0.001), and valvular heart disease (aOR = 1.3, 95% CI = 1.2-1.35, p < 0.001). The odds were similar between the two groups for developing cardiac arrest (aOR = 0.86, 95% CI = 0.8-0.98, p = 0.05). Conclusions Adults with thoracic malignancies who were treated with RT have higher odds of developing chronic pericarditis, acute pericarditis, constrictive pericarditis, conduction disorders, coronary artery disease, heart failure, and valvular heart disease while similar odds of developing cardiac arrest or acute myocardial infarction compared to the general adult population.

Mobitz II Atrioventricular Block Following Intracardiac Radiation to the Right Ventricular Outflow Tract

Cardiac complications from mediastinal radiotherapy are much more prevalent than in years past and are becoming a significant cause of morbidity and mortality in these patients following treatment. We describe a patient with metastatic lung adenosquamous carcinoma extending to the right ventricular outflow tract who would develop a Mobitz type II atrioventricular block following intracardiac radiation therapy requiring permanent pacemaker placement.

TLR4-A Pertinent Player in Radiation-Induced Heart Disease?

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.

Ion Channels in the Development and Remodeling of the Aortic Valve

The role of ion channels is extensively described in the context of the electrical activity of excitable cells and in excitation-contraction coupling. They are, through this phenomenon, a key element for cardiac activity and its dysfunction. They also participate in cardiac morphological remodeling, in particular in situations of hypertrophy. Alongside this, a new field of exploration concerns the role of ion channels in valve development and remodeling. Cardiac valves are important components in the coordinated functioning of the heart by ensuring unidirectional circulation essential to the good efficiency of the cardiac pump. In this review, we will focus on the ion channels involved in both the development and/or the pathological remodeling of the aortic valve. Regarding valve development, mutations in genes encoding for several ion channels have been observed in patients suffering from malformation, including the bicuspid aortic valve. Ion channels were also reported to be involved in the morphological remodeling of the valve, characterized by the development of fibrosis and calcification of the leaflets leading to aortic stenosis. The final stage of aortic stenosis requires, until now, the replacement of the valve. Thus, understanding the role of ion channels in the progression of aortic stenosis is an essential step in designing new therapeutic approaches in order to avoid valve replacement.

Dang Gui Bu Xue Tang, a conventional Chinese herb decoction, ameliorates radiation-induced heart disease via Nrf2/HMGB1 pathway

Introduction: Radiation-induced heart disease (RIHD), characterized by cardiac dysfunction and myocardial fibrosis, is one of the most common complications after cardiothoracic radiotherapy. Dang Gui Bu Xue Tang (DBT) is a conventional Chinese herb decoction composed of Radix Astragali membranaceus (RAM) and Radix Angelicae sinensis (RAS) at a ratio of 5:1, famous for its "blood-nourishing" effect. In this study, we aimed to investigate the cardioprotective effect of DBT on RIHD. Methods: C57BL mice at 8 weeks of age were divided into five groups, namely Control, Radiation, RDBT51 (Radiation with DBT, RAM:RAS = 5:1), RDBT11 (Radiation with DBT, RAM:RAS = 1:1), and RDBT15 (Radiation with DBT, RAM:RAS = 1:5). Results: We mainly found that radiation in the cardiothoracic region led to significant left ventricular systolic dysfunction, myocardial fibrotic lesions and cardiac injury accompanied by abnormally increased myocardial HMGB1 protein levels. Administration of conventional DBT significantly ameliorated left ventricular systolic dysfunction, alleviated myocardial fibrosis, and counteracted cardiac injury, all of which supported the protective effect of DBT on RIHD, involving upregulation of myocardial Nrf2 protein levels and downregulation of HMGB1 protein levels as underlying mechanisms. Conclusions: DBT exerts a significant protective effect on RIHD, and the Nrf2/ HMGB1 pathway probably plays an important role in this protective effect.

Cardiac Adverse Events Associated With Chemo-Radiation Versus Chemotherapy for Resectable Stage III Non-Small-Cell Lung Cancer: A Surveillance, Epidemiology and End Results-Medicare Study

Background We compared cardiac outcomes for surgery-eligible patients with stage III non-small-cell lung cancer treated adjuvantly or neoadjuvantly with chemotherapy versus chemo-radiation therapy in the Surveillance, Epidemiology and End Results-Medicare database. Methods and Results Patients were age 66+, had stage IIIA/B resectable non-small-cell lung cancer diagnosed between 2007 and 2015, and received adjuvant or neoadjuvant chemotherapy or chemo-radiation within 121 days of diagnosis. Patients having chemo-radiation and chemotherapy only were propensity-score matched and followed from day 121 to first cardiac outcome, noncardiac death, radiation initiation by patients who received chemotherapy only, fee-for-service enrollment interruption, or December 31, 2016. Cause-specific hazard ratios (HRs) and competing risks subdistribution HRs were estimated. The primary outcome was the first of these severe cardiac events: acute myocardial infarction, other hospitalized ischemic heart disease, hospitalized heart failure, percutaneous coronary intervention/coronary artery bypass graft, cardiac death, or urgent/inpatient care for pericardial disease, conduction abnormality, valve disorder, or ischemic heart disease. With median follow-up of 13 months, 70 of 682 patients who received chemo-radiation (10.26%) and 43 of 682 matched patients who received chemotherapy only (6.30%) developed a severe cardiac event (P=0.008) with median time to first event 5.45 months. Chemo-radiation increased the rate of severe cardiac events (cause-specific HR: 1.62 [95% CI, 1.11-2.37] and subdistribution HR: 1.41 [95% CI, 0.97-2.04]). Cancer severity appeared greater among patients who received chemo-radiation (noncardiac death cause-specific HR, 2.53 [95% CI, 1.93-3.33] and subdistribution HR, 2.52 [95% CI, 1.90-3.33]). Conclusions Adding radiation therapy to chemotherapy is associated with an increased risk of severe cardiac events among patients with resectable stage III non-small-cell lung cancer for whom survival benefit of radiation therapy is unclear.

MG149 Inhibits MOF-Mediated p53 Acetylation to Attenuate X-Ray Radiation-Induced Apoptosis in H9c2 Cells

Cardiomyocyte apoptosis is involved in the pathogenesis of radiation-induced heart disease, but the underlying epigenetic mechanism remains elusive. We evaluated the potential mediating role of males absent on the first (MOF) in the association between epigenetic activation of p53 lysine 120 (p53K120) and X-ray radiation-induced apoptosis in H9c2 cells. H9c2 cells were pretreated for 24 h with the MOF inhibitor MG149 after 4 Gy irradiation, followed by assessment of cell proliferation, injury, and apoptosis. MOF expression was upregulated by X-ray radiation. MG149 suppressed the proliferation inhibition, reduction of mitochondrial membrane potential, ROS production, and cell apoptosis. MG149 may promote the survival of H9c2 cells via inhibition of MOF-mediated p53K120 acetylation in response to X-ray radiation-induced apoptosis. Our data indicates a MOF-associated epigenetic mechanism in H9c2 cells that promotes attenuation of X-ray radiation-induced injury.

[Radiation-Induced Heart Disease: Current Status and Challenges]

Being one of the major therapeutic measures for malignant tumors, radiation therapy, or radiotherapy, plays a particularly crucial role in the multidisciplinary integrated treatment of thoracic tumors. With the development in radiotherapy technology, the research focus has shifted from improving the overall survival of malignant tumor patients to reducing the incidence of radiation-related injuries. Currently, radiation-induced heart disease (RIHD) has become one of the leading non-cancer causes of death in thoracic tumor patients who have undergone radiotherapy, seriously affecting their quality of life and clinical prognosis. In recent years, there has been growing understanding of the pathogenesis of RIHD, and proposals have been made for some potential measures for the prevention and treatment of RIHD. Based on the clinical manifestations and pathological changes of RIHD that have been reported, we herein reviewed the biological mechanism and potential treatment options for RIHD. We also discussed existing challenges in the prevention and treatment of RIHD, intending to provide references for the prevention and treatment of RIHD.

TRPM4 Participates in Irradiation-Induced Aortic Valve Remodeling in Mice

Simple Summary

Despite its benefit in cancer treatment, thoracic irradiation can induce aortic valve stenosis with fibrosis and calcification. The TRPM4 cation channel is known to participate in cellular remodeling including the transition of cardiac fibroblasts to myofibroblasts, similar to that observed during aortic valve stenosis. This study evaluates if TRPM4 is involved in irradiation-induced aortic valve damage. The aortic valve of mice was targeted by irradiation. Cardiac echography 5 months after treatment revealed an increase in aortic jet velocity, indicating stenosis. This was not observed in non-treated animals. Histological analysis revealed an increase in valvular cusp surface associated with fibrosis which was not observed in non-treated animals. The experiments were reproduced on mice after Trpm4 gene disruption. In these animals, irradiation did not induce valvular remodeling. It indicates that TRPM4 influences irradiation-induced aortic valve damage and thus could be a target to prevent such side effects of irradiation.

Abstract

Thoracic radiotherapy can lead to cardiac remodeling including valvular stenosis due to fibrosis and calcification. The monovalent non-selective cation channel TRPM4 is known to be involved in calcium handling and to participate in fibroblast transition to myofibroblasts, a phenomenon observed during aortic valve stenosis. The goal of this study was to evaluate if TRPM4 is involved in irradiation-induced aortic valve damage. Four-month-old Trpm4^+/+ and Trpm4^−/− mice received 10 Gy irradiation at the aortic valve. Cardiac parameters were evaluated by echography until 5 months post-irradiation, then hearts were collected for morphological and histological assessments. At the onset of the protocol, Trpm4^+/+ and Trpm4^−/− mice exhibited similar maximal aortic valve jet velocity and mean pressure gradient. Five months after irradiation, Trpm4^+/+ mice exhibited a significant increase in those parameters, compared to the untreated animals while no variation was detected in Trpm4^−/− mice. Morphological analysis revealed that irradiated Trpm4^+/+ mice exhibited a 53% significant increase in the aortic valve cusp surface while no significant variation was observed in Trpm4^−/− animals. Collagen staining revealed aortic valve fibrosis in irradiated Trpm4^+/+ mice but not in irradiated Trpm4^−/− animals. It indicates that TRPM4 influences irradiation-induced valvular remodeling.

Acetylation of Atp5f1c Mediates Cardiomyocyte Senescence via Metabolic Dysfunction in Radiation-Induced Heart Damage

Objective

Ionizing radiation (IR) causes cardiac senescence, which eventually manifests as radiation-induced heart damage (RIHD). This study is aimed at exploring the mechanisms underlying IR-induced senescence using acetylation proteomics.

Methods

Irradiated mouse hearts and H9C2 cells were harvested for senescence detection. Acetylation proteomics was used to investigate alterations in lysine acetylation. Atp5f1c acetylation after IR was verified using coimmunoprecipitation (Co-IP). Atp5f1c lysine 55 site acetylation (Atp5f1c K55-Ac) point mutation plasmids were used to evaluate the influence of Atp5f1c K55-Ac on energy metabolism and cellular senescence. Deacetylation inhibitors, plasmids, and siRNA transfection were used to determine the mechanism of Atp5f1c K55-Ac regulation.

Results

The mice showed cardiomyocyte and cardiac aging phenotypes after IR. We identified 90 lysine acetylation sites from 70 protein alterations in the heart in response to IR. Hyperacetylated proteins are primarily involved in energy metabolism. Among them, Atp5f1c was hyperacetylated, as confirmed by Co-IP. Atp5f1c K55-Ac decreased ATP enzyme activity and synthesis. Atp5f1c K55 acetylation induced cardiomyocyte senescence, and Sirt4 and Sirt5 regulated Atp5f1c K55 deacetylation.

Conclusion

Our findings reveal a mechanism of RIHD through which Atp5f1c K55-Ac leads to cardiac aging and Sirt4 or Sirt5 modulates Atp5f1c acetylation. Therefore, the regulation of Atp5f1c K55-Ac might be a potential target for the treatment of RIHD.

Tanshinone IIA Accomplished Protection against Radiation-Induced Cardiomyocyte Injury by Regulating the p38/p53 Pathway

Background

Radiotherapy is one of the major strategies for treating tumors, and it inevitably causes damage to relevant tissues and organs during treatment. Radiation-induced heart disease (RIHD) refers to radiation-induced cardiovascular adverse effects caused by thoracic radiotherapy. Currently, there is no uniform standard in the treatment of RIHD.

Methods

In our group study, by administering a dose of 4 Gy radiation, we established a radiation injured cardiomyocyte model and explored the regulatory relationship between tanshinone IIA and p38 MAPK in cardiomyocyte injury. We assessed cell damage and proliferation using clonogenic assay and lactate dehydrogenase (LDH) release assay. The measures of antioxidant activity and oxidative stress were conducted using superoxide dismutase (SOD) and reactive oxygen species (ROS). The apoptosis rate and the relative expression of apoptotic proteins were conducted using flow cytometry and western blot. To assess p38 and p53 expressions and phosphorylation levels, western blot was performed.

Results

Experimental results suggested that tanshinone IIA restored cell proliferation in radiation-induced cardiomyocyte injury (∗∗P < 0.01), and the level of LDH release decreased (∗P < 0.05). Meanwhile, tanshinone IIA could decrease the ROS generation induced by radiation (∗∗P < 0.01) and upregulate the SOD level (∗∗P < 0.01). Again, tanshinone IIA reduced radiation-induced cardiomyocyte apoptosis (∗∗P < 0.01). Finally, tanshinone IIA downregulated radiation-induced p38/p53 overexpression (∗∗∗P < 0.001).

Conclusions

The treatment effects of tanshinone IIA against radiation-induced myocardial injury may be through the regulation of the p38/p53 pathway.

Pharmaceutical Prevention and Management of Cardiotoxicity in Hematological Malignancies

Modern treatment modalities in hematology have improved clinical outcomes of patients with hematological malignancies. Nevertheless, many new or conventional anticancer drugs affect the cardiovascular system, resulting in various cardiac disorders, including left ventricular dysfunction, heart failure, arterial hypertension, myocardial ischemia, cardiac rhythm disturbances, and QTc prolongation on electrocardiograms. As these complications may jeopardize the significantly improved outcome of modern anticancer therapies, it is crucial to become familiar with all aspects of cardiotoxicity and provide appropriate care promptly to these patients. In addition, established and new drugs contribute to primary and secondary cardiovascular diseases prevention. This review focuses on the clinical manifestations, preventive strategies, and pharmaceutical management of cardiotoxicity in patients with hematologic malignancies undergoing anticancer drug therapy or hematopoietic stem cell transplantation.

Effectiveness of Proanthocyanidin plus Trimetazidine in the Treatment of Non-Small-Cell Lung Cancer with Radiation Heart Injury

This study was intended to explore the effect of proanthocyanidin (PC) combined with trimetazidine in non-small-cell lung cancer (NSCLC) with radiation-induced heart damage (RIHD). It was a prospective randomized controlled study that 86 NSCLC patients with radiation treatment in Cangzhou People's Hospital from January 2019 and June 2021 were enrolled and randomized to either the control group or the study group via the random table method, 43 cases in each group. The control group received trimetazidine, and the study group additionally received PC. The incidence of RIHD-related clinical manifestation, RIHD-related ECG, and RIHD-related cardiac ultrasound change were all lower in the study group. After radiotherapy, the serum level of superoxide dismutase (SOD) was higher, and malondialdehyde (MDA) was lower in the study group when compared with the control group. After radiotherapy, the serum levels of brain natriuretic peptide (BNP), cardiac troponin (cTnT), creatine kinase (CK), and creatine kinase isoenzymes (CKMB) were all lower in the study group when compared with the control group. The efficacy of PC plus trimetazidine for NSCLC with RIHD is superior to trimetazidine alone, and it significantly mitigates radiation-induced inflammatory response and oxidative stress.

An overview of radiation-induced heart disease

Radiation therapy (RT) has dramatically improved cancer survival, leading to several inevitable complications. Unintentional irradiation of the heart can lead to radiation-induced heart disease (RIHD), including cardiomyopathy, pericarditis, coronary artery disease, valvular heart disease, and conduction system abnormalities. Furthermore, the development of RIHD is aggravated with the addition of chemotherapy. The screening, diagnosis, and follow-up for RIHD in patients who have undergone RT are described by the consensus guidelines from the European Association of Cardiovascular Imaging (EACVI) and the American Society of Echocardiography (ASE). There is compelling evidence that chest RT can increase the risk of heart disease. Although the prevalence and severity of RIHD are likely to be reduced with modern RT techniques, the incidence of RIHD is expected to rise in cancer survivors who have been treated with old RT regimens. However, there remains a gap between guidelines and clinical practice. Currently, therapeutic modalities followed in the treatment of RIHD are similar to the non-irradiated population. Preventive measures mainly reduce the radiation dose and radiation volume of the heart. There is no concrete evidence to endorse the preventive role of statins, angiotensin-converting enzyme inhibitors, and antioxidants. This review summarizes the current evidence of RIHD subtypes and risk factors and suggests screening regimens, diagnosis, treatment, and preventive approaches.

Investigation of the Antiremodeling Effects of Losartan, Mirabegron and Their Combination on the Development of Doxorubicin-Induced Chronic Cardiotoxicity in a Rat Model

Despite the effectiveness of doxorubicin (DOXO) as a chemotherapeutic agent, dose-dependent development of chronic cardiotoxicity limits its application. The angiotensin-II receptor blocker losartan is commonly used to treat cardiac remodeling of various etiologies. The beta-3 adrenergic receptor agonist mirabegron was reported to improve chronic heart failure. Here we investigated the effects of losartan, mirabegron and their combination on the development of DOXO-induced chronic cardiotoxicity. Male Wistar rats were divided into five groups: (i) control; (ii) DOXO-only; (iii) losartan-treated DOXO; (iv) mirabegron-treated DOXO; (v) losartan plus mirabegron-treated DOXO groups. The treatments started 5 weeks after DOXO administration. At week 8, echocardiography was performed. At week 9, left ventricles were prepared for histology, qRT-PCR, and Western blot measurements. Losartan improved diastolic but not systolic dysfunction and ameliorated SERCA2a repression in our DOXO-induced cardiotoxicity model. The DOXO-induced overexpression of Il1 and Il6 was markedly decreased by losartan and mirabegron. Mirabegron and the combination treatment improved systolic and diastolic dysfunction and significantly decreased overexpression of Smad2 and Smad3 in our DOXO-induced cardiotoxicity model. Only mirabegron reduced DOXO-induced cardiac fibrosis significantly. Mirabegron and its combination with losartan seem to be promising therapeutic tools against DOXO-induced chronic cardiotoxicity.

Pharmacological ACE-inhibition Mitigates Radiation-Induced Pneumonitis by Suppressing ACE-expressing Lung Myeloid Cells

PURPOSE

Radiation-induced lung injury is a major dose-limiting toxicity for thoracic radiotherapy patients. In experimental models, treatment with angiotensin converting enzyme (ACE) inhibitors mitigates radiation pneumonitis; however, the mechanism of action is not well understood. Here, we evaluate the direct role of ACE inhibition on lung immune cells.

METHODS AND MATERIALS

ACE expression and activity were determined in the lung immune cell compartment of irradiated adult rats following either high dose fractionated radiation therapy (RT) to the right lung (5 fractions x 9 Gy) or a single dose of 13.5 Gy partial body irradiation (PBI). Mitigation of radiation-induced pneumonitis with the ACE-inhibitor lisinopril was evaluated in the 13.5 Gy rat PBI model. During pneumonitis, we characterized inflammation and immune cell content in the lungs and bronchoalveolar lavage fluid (BALF). In vitro mechanistic studies were performed using primary human monocytes and the human monocytic THP-1 cell line.

RESULTS

In both the PBI and fractionated RT models, radiation increased ACE activity in lung immune cells. Treatment with lisinopril improved survival during radiation pneumonitis (p=0.0004). Lisinopril abrogated radiation-induced increases in BALF MCP-1 (CCL2) and MIP-1α cytokine levels (p < 0.0001). Treatment with lisinopril reduced both ACE expression (p=0.006) and frequency of CD45⁺CD11b⁺ lung myeloid cells (p=0.004). In vitro, radiation injury acutely increased ACE activity (p=0.045) and reactive oxygen species (ROS) generation (p=0.004) in human monocytes, whereas treatment with lisinopril blocked radiation-induced increases in both ACE and ROS. Interestingly, radiation-induced ROS generation was blocked by pharmacological inhibition of either NADPH oxidase 2 (NOX2) (p=0.012) or the type 1 angiotensin receptor (AGTR1) (p=0.013).

CONCLUSIONS

These data demonstrate radiation-induced ACE activation within the immune compartment promotes the pathogenesis of radiation pneumonitis, while ACE inhibition suppresses activation of pro-inflammatory immune cell subsets. Mechanistically, our in vitro data demonstrate radiation directly activates the ACE/AGTR1 pathway in immune cells and promotes generation of ROS via Nox2.

Investigation of the Antihypertrophic and Antifibrotic Effects of Losartan in a Rat Model of Radiation-Induced Heart Disease

Radiation-induced heart disease (RIHD) is a potential late side-effect of thoracic radiotherapy resulting in left ventricular hypertrophy (LVH) and fibrosis due to a complex pathomechanism leading to heart failure. Angiotensin-II receptor blockers (ARBs), including losartan, are frequently used to control heart failure of various etiologies. Preclinical evidence is lacking on the anti-remodeling effects of ARBs in RIHD, while the results of clinical studies are controversial. We aimed at investigating the effects of losartan in a rat model of RIHD. Male Sprague-Dawley rats were studied in three groups: (1) control, (2) radiotherapy (RT) only, (3) RT treated with losartan (per os 10 mg/kg/day), and were followed for 1, 3, or 15 weeks. At 15 weeks post-irradiation, losartan alleviated the echocardiographic and histological signs of LVH and fibrosis and reduced the overexpression of chymase, connective tissue growth factor, and transforming growth factor-beta in the myocardium measured by qPCR; likewise, the level of the SMAD2/3 protein determined by Western blot decreased. In both RT groups, the pro-survival phospho-AKT/AKT and the phospho-ERK1,2/ERK1,2 ratios were increased at week 15. The antiremodeling effects of losartan seem to be associated with the repression of chymase and several elements of the TGF-β/SMAD signaling pathway in our RIHD model.