Cardiovascular disease associated with radiotherapy: activation of nuclear factor kappa-B

Reflecting on the cardiac toxicity in non-small cell lung cancer in the era of immune checkpoint inhibitors therapy combined with thoracic radiotherapy

In recent years, immune checkpoint inhibitors (ICIs) have become a widely used treatment for non-small cell lung cancer (NSCLC), and the combination with traditional radiotherapy (RT) has shown significant potential in prolonging patient survival. However, both thoracic RT and ICIs can lead to cardiac toxicity, including radiation-induced heart damage (RIHD) and immunotherapy-related heart damage (IRHD). It still remains uncertain whether the combination of thoracic RT and immunotherapy will exacerbate acute or late cardiovascular (CV) toxicity and incidence. In this review, we summarize safety data from relevant clinical studies regarding CV toxicity for the combination therapy in NSCLC patients, explore the underlying synergetic mechanisms and common risk factors, and proposed treatment and management strategies. We hope to increase emphasis on the long-term assessment of CV toxicity risks associated with the combination therapy, and reduce the incidence of CV deaths resulting from such regimens.

Novel VEGFR2 inhibitors with thiazoloquinoxaline scaffold targeting hepatocellular carcinoma with lower cardiotoxic impact

Hepatocellular carcinoma (HCC) is a fatal tumor which is usually diagnosed at advanced stage. Molecular targeted drugs were used recently to treat HCC, however, due to serious side effects, mainly cardiotoxicity and emergence of resistance, there is demanding to explore new chemotherapeutics. 10 novel thiazoloquinoxaline derivatives coupled with different sulfonamide moieties 4(a-j) were designed and synthesized fulfilling pharmacophoric features of VEGFR-2 inhibition. Structures of all new compounds were verified via spectral and microanalytical data. After carrying in-vitro VEGFR-2 assay for compounds 4(a-j); sulfapyridine and sulfamethoxazole derivatives 4d and 4f showed potential inhibitory effect [61.04 and 83.35 nM], respectively, comparable to standard sorafenib [51.41 nM]. Both were then further evaluated for their cytocidal activity against HepG2 cell-line and against myocardium cells using H9C2 cell-line. As a result, only sulfapyridine derivative 4d exhibited a significant inhibition of HepG2 cells viability [IC50 = 4.31 μM]. Furthermore, it showed relatively lower cytotoxic impact against normal H9C2 myocardium cells [IC50, 33.47 μM] compared to that of sorafenib [IC50, 98.07 μM]. In-vivo study was carried out to determine myocardium safety of compound 4d on irradiated mice (8 Gy). In-vivo results of sulfapyridine derivative 4d showed normal cardiac enzyme function (CK) and serum catalase activity with significant reductions in LDH, cardiac TNF-α and caspase-9 levels, alongside with its efficacy in suppressing the expression of hepatic VEGF. In conclusion, sulfapyridine derivative 4d could be considered a promising candidate as VEGFR-2 inhibitor with less myocardium side effect.

Identification of circRNAs and circRNA-miRNA-mRNA regulatory network in radiation-induced heart disease

OBJECTIVE

Radiation-induced heart disease (RIHD) is one of the most common and serious long-term adverse effect after thoracic radiotherapy. Our aim was to investigate the potential molecular mechanism underlying RIHD using RNA-sequencing (RNA-seq) and bioinformatics methods.

MATERIALS AND METHODS

An RIHD rat model was established and transcription profiles were identified using RNA-seq. Differentially expressed circRNAs, miRNAs and mRNAs were identified. Enrichment of functions and signaling pathways analysis were performed based on GO and the KEGG database. Potential circRNA-miRNA-mRNA regulatory network underlying RIHD was established. qRT-PCR was used to validate the associated genes.

RESULTS

In total, 21 circRNAs, 26 miRNAs, and 178 mRNA transcripts were differentially expressed in RIHD. GO and KEGG pathway analyses identified that differentially expressed mRNAs were most enriched in pathways referring to endothelial function and vascular pathological processes. Nine circRNAs, 10 miRNAs, and 6 mRNA transcripts were most likely involved in vascular function and a candidate competitive endogenous RNA (ceRNA) network of circRNA-miRNA-mRNA was established, which were further validated by qRT-PCR.

CONCLUSIONS

Our study revealed that vascular pathology plays an important role in the early stage of RIHD. Furthermore, a circRNA-miRNA-mRNA ceRNA network was found that may be involved in the regulation of vascular function and RIHD.

Radiation-induced cardiovascular disease: an overlooked role for DNA methylation?

Radiotherapy in cancer treatment involves the use of ionizing radiation for cancer cell killing. Although radiotherapy has shown significant improvements on cancer recurrence and mortality, several radiation-induced adverse effects have been documented. Of these adverse effects, radiation-induced cardiovascular disease (CVD) is particularly prominent among patients receiving mediastinal radiotherapy, such as breast cancer and Hodgkin's lymphoma patients. A number of mechanisms of radiation-induced CVD pathogenesis have been proposed such as endothelial inflammatory activation, premature endothelial senescence, increased ROS and mitochondrial dysfunction. However, current research seems to point to a so-far unexamined and potentially novel involvement of epigenetics in radiation-induced CVD pathogenesis. Firstly, epigenetic mechanisms have been implicated in CVD pathophysiology. In addition, several studies have shown that ionizing radiation can cause epigenetic modifications, especially DNA methylation alterations. As a result, this review aims to provide a summary of the current literature linking DNA methylation to radiation-induced CVD and thereby explore DNA methylation as a possible contributor to radiation-induced CVD pathogenesis.

Nucleus-mitochondria positive feedback loop formed by ERK5 S496 phosphorylation-mediated poly (ADP-ribose) polymerase activation provokes persistent pro-inflammatory senescent phenotype and accelerates coronary atherosclerosis after chemo-radiation

The incidence of cardiovascular disease (CVD) is higher in cancer survivors than in the general population. Several cancer treatments are recognized as risk factors for CVD, but specific therapies are unavailable. Many cancer treatments activate shared signaling events, which reprogram myeloid cells (MCs) towards persistent senescence-associated secretory phenotype (SASP) and consequently CVD, but the exact mechanisms remain unclear. This study aimed to provide mechanistic insights and potential treatments by investigating how chemo-radiation can induce persistent SASP. We generated ERK5 S496A knock-in mice and determined SASP in myeloid cells (MCs) by evaluating their efferocytotic ability, antioxidation-related molecule expression, telomere length, and inflammatory gene expression. Candidate SASP inducers were identified by high-throughput screening, using the ERK5 transcriptional activity reporter cell system. Various chemotherapy agents and ionizing radiation (IR) up-regulated p90RSK-mediated ERK5 S496 phosphorylation. Doxorubicin and IR caused metabolic changes with nicotinamide adenine dinucleotide depletion and ensuing mitochondrial stunning (reversible mitochondria dysfunction without showing any cell death under ATP depletion) via p90RSK-ERK5 modulation and poly (ADP-ribose) polymerase (PARP) activation, which formed a nucleus-mitochondria positive feedback loop. This feedback loop reprogramed MCs to induce a sustained SASP state, and ultimately primed MCs to be more sensitive to reactive oxygen species. This priming was also detected in circulating monocytes from cancer patients after IR. When PARP activity was transiently inhibited at the time of IR, mitochondrial stunning, priming, macrophage infiltration, and coronary atherosclerosis were all eradicated. The p90RSK-ERK5 module plays a crucial role in SASP-mediated mitochondrial stunning via regulating PARP activation. Our data show for the first time that the nucleus-mitochondria positive feedback loop formed by p90RSK-ERK5 S496 phosphorylation-mediated PARP activation plays a crucial role of persistent SASP state, and also provide preclinical evidence supporting that transient inhibition of PARP activation only at the time of radiation therapy can prevent future CVD in cancer survivors.

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

Cancer management has undergone significant improvements, which led to increased long-term survival rates among cancer patients. Radiotherapy (RT) has an important role in the treatment of thoracic tumors, including breast, lung, and esophageal cancer, or Hodgkin's lymphoma. RT aims to kill tumor cells; however, it may have deleterious side effects on the surrounding normal tissues. The syndrome of unwanted cardiovascular adverse effects of thoracic RT is termed radiation-induced heart disease (RIHD), and the risk of developing RIHD is a critical concern in current oncology practice. Premature ischemic heart disease, cardiomyopathy, heart failure, valve abnormalities, and electrical conduct defects are common forms of RIHD. The underlying mechanisms of RIHD are still not entirely clear, and specific therapeutic interventions are missing. In this review, we focus on the molecular pathomechanisms of acute and chronic RIHD and propose preventive measures and possible pharmacological strategies to minimize the burden of RIHD.

Radiation Response of Human Cardiac Endothelial Cells Reveals a Central Role of the cGAS-STING Pathway in the Development of Inflammation

Radiation-induced inflammation leading to the permeability of the endothelial barrier may increase the risk of cardiovascular disease. The aim of this study was to investigate potential mechanisms in vitro at the level of the proteome in human coronary artery endothelial cells (HCECest2) that were exposed to radiation doses of 0, 0.25, 0.5, 2.0 and 10 Gy (60Co-γ). Proteomics analysis was performed using mass spectrometry in a label-free data-independent acquisition mode. The data were validated using bioinformatics and immunoblotting. The low- and moderate-dose-irradiated samples (0.25 Gy, 0.5 Gy) showed only scarce proteome changes. In contrast, an activation of DNA-damage repair, inflammation, and oxidative stress pathways was seen after the high-dose treatments (2 and 10 Gy). The level of the DNA damage response protein DDB2 was enhanced early at the 10 Gy dose. The expression of proteins belonging to the inflammatory response or cGAS-STING pathway (STING, STAT1, ICAM1, ISG15) increased in a dose-dependent manner, showing the strongest effects at 10 Gy after one week. This study suggests a connection between the radiation-induced DNA damage and the induction of inflammation which supports the inhibition of the cGAS-STING pathway in the prevention of radiation-induced cardiovascular disease.

BRCA1 protects cardiac microvascular endothelial cells against irradiation by regulating p21-mediated cell cycle arrest

AIMS

Microvascular endothelial cell dysfunction is a leading cause of radiation-induced heart disease (RIHD). BRCA1 plays an important role in DNA damage repair. The study aims to explore the effect of BRCA1 in endothelial cells involved in RIHD.

MATERIALS AND METHODS

BRCA1 and p21 expression were detected in human umbilical vein endothelial cells (HUVECs) and in mouse heart tissue after irradiation exposure. The effects of BRCA1 on cell proliferation, cell cycle and radiosensitivity were determined in HUVECs with overexpression and knockdown of BRCA1. A mouse model of RIHD was established. Heart damage was detected in C57BL/6J mice and endothelial cell specific knockout BRCA1 mice (EC-BRCA1^-/-).

KEY FINDINGS

BRCA1 and p21 expression was significantly increased both in vitro and vivo response to irradiation. BRCA1 overexpression in endothelial cells enhanced cell growth and G1/S phase arrest, and the opposite results were observed in BRCA1 knockdown endothelial cells. BRCA1 downregulated endothelial cell cycle-related genes cyclin A, cyclin D1, cyclin E and p-Rb through increasing p21 expression, and HUVECs with BRCA1 gene knockdown were more sensitive to radiation. In vivo, a decrease in cardiac microvascular density, as well as cardiomyocyte hypoxia and apoptosis were observed in a time-dependent manner. EC-BRCA1^-/- mice were more prone to severe RIHD than EC-BRCA1^+/- mice after 16Gy radiation exposure due to endothelial dysfunction caused by loss of BRCA1, and p21 was declined in EC-BRCA1^-/- mice heart.

SIGNIFICANCE

These findings indicate that BRCA1 plays a protective role in RIHD by regulating endothelial cell cycle arrest mediated by p21 signal.

Pyropheophorbide-α methyl ester-mediated photodynamic therapy induces apoptosis and inhibits LPS-induced inflammation in RAW264.7 macrophages

BACKGROUND

This study aimed to determine the effect of pyropheophorbide-α methyl ester (MPPa)-mediated photodynamic therapy (MPPa-PDT) on the apoptosis and inflammation of murine macrophage RAW264.7 cells.

METHODS

Uptake and subcellular localization of MPPa was detected by flow cytometry and confocal fluorescence microscope. Cell viability was assessed by CCK-8; ROS levels were assessed by DCFH-DA. Cell apoptosis was measured by flow cytometry and Hoechst 33342 staining, whereas mitochondrial membrane potential was detected by JC-1 staining. Secretion of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) was determined using ELISA kits. Caspase-3, cleaved caspase-3, procaspase-9, cleaved caspase-9, PARP, cleaved PARP, Bcl-2, Bax, NF-κB p-p65, p-IKKα/β, and p-IκBα were measured by western blotting. Nuclear factor κB (NF-κB)-p65 nuclear translocation was observed by immunofluorescence.

RESULTS

MPPa -PDT influenced cell viability in a light dose-dependent manner. It induced ROS formation and RAW264.7 cell apoptosis. It also increased the expression of cleaved caspase-3, cleaved caspase-9, cleaved PARP and Bax, decreased the expression of Bcl-2. While TNF-α, IL-1β, and IL-6 increased in LPS group (model of inflammation), it deceased in LPS-MPPa-PDT group. NF-κB p-p65, p-IKKα/β, and p-IκBα had higher expression in LPS group while that reduced in LPS-MPPa-PDT group. Simultaneously, MPPa-PDT inhibited nuclear translocation of NF-κB-p65 caused by LPS.

CONCLUSIONS

MPPa-PDT can induce apoptosis and attenuate inflammation in mouse RAW264.7 macrophages, thereby suggesting a promising therapy for atherosclerosis.

Upregulation of Plasminogen Activator Inhibitor-1 in Irradiated Recipient Arteries and Veins from Free Tissue Transfer Reconstruction in Cancer Patients

Background

Clinical studies have shown that radiotherapy can induce vascular disease at the site of exposure but is usually not clinically evident until years after treatment. We have studied irradiated human arteries and veins to better understand the underlying biology in search of future treatments. The aim was to investigate whether radiotherapy contributed to a sustained expression of plasminogen activator inhibitor-1 (PAI-1) in human arteries and veins.

Methods

Irradiated arteries and veins were harvested, together with unirradiated control vessels, from patients undergoing free tissue transfer reconstruction at a median time of 90 weeks [5–650] following radiation exposure. Differential gene expression of PAI-1 was analysed, together with immunohistochemistry (IHC) and immunofluorescence (IF).

Results

PAI-1 gene expression was increased in both arteries (p = 0.012) and veins (p < 0.001) in irradiated compared to unirradiated control vessels. IHC and IF indicated that cells expressing PAI-1 were located in the adventitia of both arteries and veins and colocalized with cells positive for CD68, CD45, and α-SMA in arteries and with CD45 and α-SMA in veins.

Conclusion

The current study shows a sustained upregulation of PAI-1 in both arteries and veins after exposure to ionizing radiation, indicating a chronic inflammation mainly in the adventitia. We believe that the results contribute to further understanding of radiation-induced vascular disease, where targeting PAI-1 may be a potential treatment.

Interplay of Autophagy Inducer Rapamycin and Proteasome Inhibitor MG132 in Reduction of Foam Cell Formation and Inflammatory Cytokine Expression

MG132 is a pivotal inhibitor of the ubiquitin-proteasome system (UPS), and rapamycin (RAPA) is an important inducer of autophagy. MG132 and RAPA have been shown to be effective agents that can cure multiple autoimmune diseases by reducing inflammation. Although individual MG132 and RAPA showed protective effects for atherosclerosis (AS), the combined effect of these two drugs and its molecular mechanism are still unclear. In this article we investigate the regulation of oxidative modification of low-density lipoprotein (ox-LDL) stress and foam cell formation in the presence of both proteasome inhibitor MG132 and the autophagy inducer RAPA to uncover the molecular mechanism underlying this process. We established the foam cells model by ox-LDL and an animal model. Then, we tested six experimental groups of MG132, RAPA, and 3MA drugs. As a result, RAPA-induced autophagy reduces accumulation of polyubiquitinated proteins and apoptosis of foam cells. The combination of MG132 with RAPA not only suppressed expression of the inflammatory cytokines and formation of macrophage foam cells, but also significantly affected the NF-κB signaling pathway and the polarization of RAW 264.7 cells. These data suggest that the combination of proteasome inhibitor and autophagy inducer ameliorates the inflammatory response and reduces the formation of macrophage foam cells during development of AS. Our research provides a new way to suppress vascular inflammation and stabilize plaques of late atherosclerosis.

The importance of the vascular endothelial barrier in the immune-inflammatory response induced by radiotherapy

Altered by ionising radiation, the vascular network is considered as a prime target to limit normal tissue damage and improve tumour control in radiotherapy (RT). Irradiation damages and/or activates endothelial cells, which then participate in the recruitment of circulating cells, especially by overexpressing cell adhesion molecules, but also by other as yet unknown mechanisms. Radiation-induced lesions are associated with infiltration of immune-inflammatory cells from the blood and/or the lymph circulation. Damaged cells from the tissues and immune-inflammatory resident cells release factors that attract cells from the circulation, leading to the restoration of tissue balance by fighting against infection, elimination of damaged cells and healing of the injured area. In normal tissues that surround the tumours, the development of an immune-inflammatory reaction in response to radiation-induced tissue injury can turn out to be chronic and deleterious for the organ concerned, potentially leading to fibrosis and/or necrosis of the irradiated area. Similarly, tumours can elicit an immune-inflammation reaction, which can be initialised and amplified by cancer therapy such as radiotherapy, although immune checkpoints often allow many cancers to be protected by inhibiting the T-cell signal. Herein, we have explored the involvement of vascular endothelium in the fate of healthy tissues and tumours undergoing radiotherapy. This review also covers current investigations that take advantage of the radiation-induced response of the vasculature to spare healthy tissue and/or target tumours better.

Short- and long-term risks of cardiovascular disease following radiotherapy in rectal cancer in four randomized controlled trials and a population-based register

AIM

A population-based cohort and four randomized trials enriched with long-term register data were used to clarify if radiotherapy in combination with rectal cancer surgery is associated with increased risks of cardiovascular disease (CVD).

METHODS

We identified 14,901 rectal cancer patients diagnosed 1995-2009 in Swedish nationwide registers, of whom 9227 were treated with preoperative radiotherapy. Also, we investigated 2675 patients with rectal cancer previously randomized to preoperative radiotherapy or not followed by surgery in trials conducted 1980-1999. Risks of CVD overall and subtypes were estimated based on prospectively recorded hospital visits during relapse-free follow-up using multivariable Cox regression. Maximum follow-up was 18 and 33 years in the register and trials, respectively.

RESULTS

We found no association between preoperative radiotherapy and overall CVD risk in the register (Incidence Rate Ratio, IRR = 0.99, 95% confidence interval (CI) 0.92-1.06) or in the pooled trials (IRR = 1.07, 95% CI 0.93-1.24). We noted an increased risk of venous thromboembolism among irradiated patients in both cohorts (IRR_register = 1.41, 95% CI 1.15-2.72; IRR_trials = 1.41, 95% CI 0.97-2.04), that remained during the first 6 months following surgery among patients treated 2006-2009, after the introduction of antithrombotic treatment (IRR_{6 months} = 2.30, 95% CI 1.01-5.21). However, the absolute rate difference of venous thromboembolism attributed to RT was low (10 cases per 1000 patients and year).

DISCUSSION

Preoperative radiotherapy did not affect rectal cancer patients' risk of CVD overall. Although an excess risk of short-term venous thromboembolism was noted, the small increase in absolute numbers does not call for general changes in routine prophylactic treatment, but might do so for patients already at high risk of venous thromboembolism.

The Use of Primary Prevention Statin Therapy in Those Predisposed to Atherosclerosis

PURPOSE OF REVIEW

Many guidelines exist for the use of statins in the primary prevention of atherosclerotic cardiovascular disease (ASCVD). Few have focused on disease specific states that predispose to ASCVD. This review is intended to focus on the recommendations and evidence in inflammatory diseases that predispose to an increased risk of ASCVD beyond what conventional cardiac risk scores would predict.

RECENT FINDINGS

Certain autoimmune inflammatory diseases such as rheumatoid arthritis (RA), systemic lupus erythematous (SLE), and psoriasis/psoriatic arthritis have all been shown to increase the risk of ASCVD. Other diseases such as human immunodeficiency virus (HIV) and mediastinal radiation have also been correlated with increased ASCVD. In RA and HIV, the evidence suggests a benefit to added statin therapy and society guidelines favor early initiation. The evidence for statin therapy in RA is limited to observational studies with small secondary analysis. In HIV, there is a large ongoing clinical trial to assess efficacy. In those with psoriasis and psoriatic arthritis, there is limited evidence for or against statin therapy independent of a calculated cardiac risk score. Finally, in SLE and in those with exposure to mediastinal radiation, cardiac events remain high, but evidence is limited on the beneficial effects of statin therapy. There are many individuals who have an increased risk for ASCVD above what is predicted from a cardiac risk score. It would be beneficial to create risk prediction models with statin therapy recommendations that are tailored to those predisposed to accelerated atherosclerosis.

Radiation-induced changes in the glycome of endothelial cells with functional consequences

As it is altered by ionizing radiation, the vascular network is considered as a prime target in limiting normal tissue damage and improving tumor control in radiation therapy. Irradiation activates endothelial cells which then participate in the recruitment of circulating cells, especially by overexpressing cell adhesion molecules, but also by other as yet unknown mechanisms. Since protein glycosylation is an important determinant of cell adhesion, we hypothesized that radiation could alter the glycosylation pattern of endothelial cells and thereby impact adhesion of circulating cells. Herein, we show that ionizing radiation increases high mannose-type N-glycans and decreases glycosaminoglycans. These changes stimulate interactions measured under flow conditions between irradiated endothelial cells and monocytes. Targeted transcriptomic approaches in vitro in endothelial cells and in vivo in a radiation enteropathy mouse model confirm that genes involved in N- and O-glycosylation are modulated by radiation, and in silico analyses give insight into the mechanism by which radiation modifies glycosylation. The endothelium glycome may therefore be considered as a key therapeutic target for modulating the chronic inflammatory response observed in healthy tissues or for participating in tumor control by radiation therapy.

Pathology and biology of radiation-induced cardiac disease

Heart disease is the leading global cause of death. The risk for this disease is significantly increased in populations exposed to ionizing radiation, but the mechanisms are not fully elucidated yet. This review aims to gather and discuss the latest data about pathological and biological consequences in the radiation-exposed heart in a comprehensive manner. A better understanding of the molecular and cellular mechanisms underlying radiation-induced damage in heart tissue and cardiac vasculature will provide novel targets for therapeutic interventions. These may be valuable for individuals clinically or occupationally exposed to varying doses of ionizing radiation.

Exploring the Potential of Venom from Nasonia vitripennis as Therapeutic Agent with High-Throughput Screening Tools

The venom from the ectoparasitoid wasp Nasonia vitripennis (Hymenoptera: Pteromalidae) contains at least 80 different proteins and possibly even more peptides or other small chemical compounds, demonstrating its appealing therapeutic application. To better understand the dynamics of the venom in mammalian cells, two high-throughput screening tools were performed. The venom induced pathways related to an early stress response and activated reporters that suggest the involvement of steroids. Whether these steroids reside from the venom itself or show an induced release/production caused by the venom, still remains unsolved. The proinflammatory cytokine IL-1β was found to be down-regulated after venom and LPS co-treatment, confirming the anti-inflammatory action of N. vitripennis venom. When analyzing the expression levels of the NF-κB target genes, potentially not only the canonical but also the alternative NF-κB pathway can be affected, possibly explaining some counterintuitive results. It is proposed that next to an NF-κB binding site, the promoter of the genes tested by the PCR array may also contain binding sites for other transcription factors, resulting in a complex puzzle to connect the induced target gene with its respective transcription factor. Interestingly, Nasonia venom altered the expression of some drug targets, presenting the venom with an exciting therapeutical potential.

Expression of transforming growth factor beta 1-related signaling proteins in irradiated vessels

AIM

Microvascular free tissue transfer is a standard method in head and neck reconstructive surgery. However, previous radiotherapy of the operative region is associated with an increased incidence in postoperative flap-related complications and complete flap loss. As transforming growth factor beta (TGF-β) 1 and galectin-3 are well known markers in the context of fibrosis and lectin-like oxidized low-density lipoprotein 1 (LOX-1) supports vascular atherosclerosis, the aim of this study was to evaluate the expression of TGF-β1 and related markers as well as LOX-1 in irradiated vessels.

MATERIALS AND METHODS

To evaluate the expression of galectin-3, Smad 2/3, TGF-β1, and LOX-1, 20 irradiated and 20 nonirradiated arterial vessels were used for immunohistochemical staining. We semiquantitatively assessed the ratio of stained cells/total number of cells (labeling index).

RESULTS

Expression of galectin-3, Smad 2/3, and TGF-β1 was significantly increased in previously irradiated vessels compared with nonirradiated controls. Furthermore, LOX-1 was expressed significantly higher in irradiated compared with nonirradiated vessels.

CONCLUSION

Fibrosis-related proteins like galectin-3, Smad 2/3, and TGF-β1 are upregulated after radiotherapy and support histopathological changes leading to vasculopathy of the irradiated vessels. Furthermore, postoperative complications in irradiated patients can be explained by increased endothelial dysfunction caused by LOX-1 in previously irradiated patients. Consequently, not only TGF-β1 but also galectin-3 inhibitors may decrease complications after microsurgical tissue transfer.

Evaluation and management of patients with heart disease and cancer: cardio-oncology

The care for patients with cancer has advanced greatly over the past decades. A combination of earlier cancer diagnosis and greater use of traditional and new systemic treatments has decreased cancer-related mortality. Effective cancer therapies, however, can result in short- and long-term comorbidities that can decrease the net clinical gain by affecting quality of life and survival. In particular, cardiovascular complications of cancer treatments can have a profound effect on the health of patients with cancer and are more common among those with recognized or unrecognized underlying cardiovascular diseases. A new discipline termed cardio-oncology has thus evolved to address the cardiovascular needs of patients with cancer and optimize their care in a multidisciplinary approach. This review provides a brief introduction and background on this emerging field and then focuses on its practical aspects including cardiovascular risk assessment and prevention before cancer treatment, cardiovascular surveillance and therapy during cancer treatment, and cardiovascular monitoring and management after cancer therapy. The content of this review is based on a literature search of PubMed between January 1, 1960, and February 1, 2014, using the search terms cancer, cardiomyopathy, cardiotoxicity, cardio-oncology, chemotherapy, heart failure, and radiation.

Radiation-induced heart disease: an under-recognized entity?

OPINION STATEMENT

Radiation-induced heart disease (RIHD) represents a spectrum of cardiovascular disease in patients who have undergone mediastinal, thoracic, or breast radiotherapy (RT). RIHD may involve any cardiac structure and is a major cause of morbidity and mortality in cancer survivors. While large cohort studies have demonstrated that symptomatic RIHD is a common late finding in this population, the incidence of asymptomatic disease is likely to be even higher. Long-term follow-up with regular screening for RIHD plays an important role in the management of cancer survivors who have undergone RT. Aggressive modification of traditional cardiovascular risk factors such as hypertension, dyslipidemia, and cigarette smoking is essential in patients at risk for RIHD, as these have been shown to potentiate the risks of radiation. In patients with symptomatic RIHD, medical and/or percutaneous therapies are often preferable to surgical interventions in view of the increased surgical risk associated with radiation damage to surrounding tissues. Percutaneous revascularization should generally be favored over surgical revascularization. Transcatheter valve replacements have not been widely used in this population but may offer an alternative to high-risk surgical valve procedures. Pericardiectomy is usually associated with extremely poor short-term and long-term outcomes in patients with RIHD and should be avoided in most cases. Heart transplantation is also higher risk in patients with RIHD than in patients with other etiologies of heart failure, but may be considered in young patients without other comorbidities.

High incidence of ischemic stroke occurrence in irradiated lung cancer patients: a population-based surgical cohort study

Background and Purpose

A high risk of stroke occurrence has been reported in several types of irradiated cancer patients. However, clinical data are lacking in irradiated lung cancer patients. The present study intended to explore a risk level of ischemic stroke occurrence in irradiated lung cancer patients.

Methods

A nationwide population-based database obtained from the Taiwan National Health Insurance was analyzed. Between 2003 and 2006, we recruited 560 resected lung cancer patients into two study groups: surgery-plus-irradiation (n = 112) and surgery-alone (n = 448). Patients treated with chemotherapy were excluded. Propensity score match was used for pairing cases with a ratio of 1∶4. Two-year ischemic-stroke-free survival was defined as the primary endpoint.

Results

Three observations supported a high risk of ischemic stroke occurrence in patients with postoperative irradiation when compared with those patients with surgery alone: first, a high incidence per 1,000 person-year (22.3 versus 11.2, 1.99 folds); second, a low two-year ischemic-stroke-free survival rate (92.2% versus 98.1%, P = 0.019); and third, a high adjusted hazard ratio (HR, 4.19; 95% CI, 1.44–12.22; P = 0.009). More notably, the highest risk of ischemic stroke occurrence was found in irradiated patients who had diabetes mellitus (HR, 34.74; 95% CI, 6.35->100; P<0.0001).

Conclusions

A high incidence of ischemic stroke was observed in irradiated lung cancer patients, especially in those with diabetes mellitus. For these patients, close clinical surveillance and strict diabetes control should be considered. Further studies to define detail biological mechanisms are encouraged.

Vascular expression of the chemokine CX3CL1 promotes osteoclast recruitment and exacerbates bone resorption in an irradiated murine model

Circulating osteoclast precursor cells highly express CX3C chemokine receptor 1 (CX3CR1), which is the only receptor for the unique CX3C membrane-anchored chemokine, fractalkine (CX3CL1). An irradiated murine model was used to evaluate the role of the CX3CL1-CX3CR1 axis in osteoclast recruitment and osteoclastogenesis. Ionizing radiation (IR) promoted the migration of circulating CD11b+ cells to irradiated bones and dose-dependently increased the number of differentiated osteoclasts in irradiated bones. Notably, CX3CL1 was dramatically upregulated in the vascular endothelium after IR. IR-induced production of CX3CL1 by skeletal vascular endothelium promoted chemoattraction of circulating CX3CR1+/CD11b+ cells and triggered homing of these osteoclast precursor cells toward the bone remodeling surface, a specific site for osteoclast differentiation. CX3CL1 also increased the endothelium-derived expression of other chemokines including stromal cell-derived factor-1 (CXCL12) and macrophage inflammatory protein-2 (CXCL2) by activating the hypoxia-inducible factor-1 α pathway. These effects may further enhance osteoclastogenesis. A series of in vivo experiments confirmed that knockout of CX3CR1 in bone marrow-derived cells and functional inhibition of CX3CL1 using a specific neutralizing antibody significantly ameliorated osteoclastogenesis and prevented bone loss after IR. These results demonstrate that the de novo CX3CL1-CX3CR1 axis plays a pivotal role in osteoclast recruitment and subsequent bone resorption, and verify its therapeutic potential as a new target for anti-resorptive treatment.

Increased long-term expression of pentraxin 3 in irradiated human arteries and veins compared to internal controls from free tissue transfers

BACKGROUND

Clinical studies have shown that radiotherapy increases the risk of cardiovascular disease at irradiated sites years after exposure. However, there is a lack of biological explanations in humans. We therefore examined human blood vessels exposed to radiotherapy and studied C-reactive protein (CRP) and pentraxin 3 (PTX3), a new marker for adverse cardiovascular outcome dependent on TNF- alpha (TNFα) or interleukin-1beta (IL-1β) expression.

METHODS

Pairs of irradiated and non-irradiated human conduit arteries and veins were harvested from the same patient during autologous free tissue transfer for cancer-reconstruction at a median time of 48 weeks after radiotherapy. Differential gene expression was studied using qRT-PCR, confirmed by immunohistochemistry and cellular origins determined by immunofluorescence.

RESULTS

Gene expression in irradiated arteries compared to non-irradiated showed a consistent up-regulation of PTX3 in all patients and in a majority of veins (p < 0.001). Both TNFα and IL-1β were increased in irradiated compared to non-irradiated arteries (p < 0.01) and IL-1β correlated to the PTX3 expression (p = 0.017). Immunohistochemical and immunofluorescence staining confirmed an increased expression of PTX3 in endothelial cells, macrophages and smooth muscle cells.

CONCLUSIONS

The sustained expression of PTX3 in arteries and veins tie biological evidence in humans to clinical studies and encourage further exploration of innate immunity in the pathogenesis of a radiation-induced vasculopathy.

Intracranial aneurysm following cranial radiation therapy

We report herein a case of a radiation-induced aneurysm. A 69-year-old woman presented with subarachnoid hemorrhage. Eight years previously, she had undergone cranial radiation therapy (total dose of 59.4 Gy) as adjuvant therapy after surgical resection for a chondrosarcoma that was destroying her sphenoid sinus. The patient underwent catheter angiography, which revealed an aneurysm of the anterior communicating artery and luminal narrowing and irregularity in the petrous and lacerum segments of the right internal carotid artery. We attempted surgical clipping of the aneurysm, but there was repeated bleeding. Finally the aneurysm was treated with endovascular trapping. Potentially fatal bleeding also occurred from her internal carotid artery, which had also been irradiated during the previous cranial radiation therapy. We stopped the bleeding with endovascular coil embolization. Because of diffuse vascular changes of the cerebral vessels within irradiated fields, special attention must be paid to their treatment.