Nanoparticle-Enhanced Near Infrared Fluorescence Imaging of Atheroma Detects Thrombosis-Prone Plaques Prior to Rupture

Introduction: Acute coronary syndromes - including unstable angina, acute myocardial infarction and sudden death - are primarily due to sudden luminal thrombosis from disruption of an atherosclerotic plaque. It has been established that inflammation plays an important role in atherogenesis and the destabilization of plaques. However, the role of inflammation in catalyzing plaque rupture is incompletely understood. Here, we experimentally investigated the in vivo spatial distribution of a novel atheroma cell targeted near-infrared fluorescence (NIRF) imaging agent, CLIO-CyAm7, prior to triggered plaque rupture, using intravascular molecular imaging. We hypothesized that CLIO-CyAm7 would illuminate macrophages on in vivo intravascular NIRF imaging and preferentially localize to atheroma that develop plaque thrombosis under triggering conditions. Methods: Atherosclerosis was induced in rabbits (n=28) using a 12-week hyperlipidemic diet with alternating 1% high cholesterol and normal chow with concomitant aortic balloon injury at 2 weeks. Rabbits were injected with 2.5mg/kg of CLIO-CyAm7 24 hours prior to in vivo imaging. In vivo NIRF and intravascular ultrasound (IVUS) imaging were used to assess baseline structural and inflammation characteristics of atheroma. Control rabbits (n=6) were sacrificed prior to triggering. Pharmacological triggering was performed using Russell’s Viper Venom (0.15mg/kg IP) and histamine (0.02mg/kg IV) injections twice over 48-hours. IVUS imaging was repeated prior to sacrifice to identify luminal thrombi in vivo. NIRF imaging was quantified using target-to-background ratio (TBR), the ratio between an area of atheroma compared to normal, uninjured aorta. A subset of rabbits (n=7) was injected with Evans Blue (6mL 0.5% IV) 30 minutes prior to sacrifice to identify permeability of the endothelium. After sacrifice, ex vivo imaging, fluorescence microscopy (FM), RAM-11 immunofluorescence (IF) of macrophages, alpha-smooth muscle actin IF for smooth muscle cells, CD31 IF for endothelial cells, and Carstairs’ staining for fibrin and collagen, were performed systematically along the length of the aorta at 1.5cm increments. Data is presented as mean±SD. Results: On microscopy, CLIO-CyAm7 localized primarily at the intimal-luminal border of atheroma, with some penetration into the media and adventitia. There was significantly higher CLIO-CyAm7 accumulation in areas of atheroma compared to control segments of the aorta (1.73±1.9% vs. 0.13±0.28%, p<0.0001). On IF, CLIO-CyAm7 signal correlated with subsets of macrophages, endothelial cells and smooth muscle cells in atheroma with minimal CLIO-CyAm7 evident in normal arteries. Evans blue showed increased endothelial permeability in regions of increased subendothelial CLIO-CyAm7 accumulation. CD31+ endothelial cells in the neovessels at the intima-media border indicated delivery of CLIO-CyAm7 via vaso vasorum. In vivo, CLIO-CyAm7+ plaques were detectable via intravascular NIRF imaging. Areas of atherosclerosis, determined by IVUS, showed significantly higher NIRF peak TBR than normal segments of the aorta (2.86±1.82 vs. 1.55±0.65, p=0.001). In vivo IVUS imaging and Carstairs’ staining for fibrin identified plaque thrombosis in 10 of 15 rabbits undergoing the triggered protocol (67%). Notably, plaques with luminal thrombosis showed significantly higher CLIO- CyAm7 accumulation compared to undisrupted atheroma (2.1±1.7% vs. 1.5±1.9%, p=0.0446), indicating that atheroma cell phagocytic capacity may underlie plaque rupture. Conclusion: CLIO-CyAm7 is a novel NIRF molecular imaging agent that identifies a subset of phagocytically active cells that are increased in atheroma prone to plaque thrombosis. Intravascular 2D NIRF imaging provides a promising future translational tool for high-resolution imaging of biologically high-risk plaques

T-cell Immunotherapy and Cardiovascular Disease: Chimeric Antigen Receptor T-cell and Bispecific T-cell Engager Therapies.

Chimeric antigen receptor (CAR) T-cell and bispecific T-cell engager (BiTE) therapies have revolutionized the treatment of refractory or relapsed leukemia and lymphoma. Increased use of these therapies has revealed signals of significant cardiotoxicity, including cardiomyopathy/heart failure, arrhythmia, myocardial injury, hemodynamic instability, and cardiovascular death mainly in the context of a profound inflammatory response to CAR T-cell antitumor effects known as cytokine release syndrome (CRS). Preexisting cardiovascular risk factors and disease may increase the risk of such cardiotoxicity. High index of suspicion and close monitoring is required for prompt recognition. Supportive hemodynamic care and targeted anti-IL-6 therapy, as well as possibly broader immunosuppression with corticosteroids, are the cornerstones of the management

Immunotherapy-Associated Cardiotoxicity of Immune Checkpoint Inhibitors and Chimeric Antigen Receptor T Cell Therapy: Diagnostic and Management Challenges and Strategies.

Immunotherapies have demonstrated robust clinical efficacy in treating malignancies with increasing use and FDA approvals. We review the epidemiology, risk factors, diagnosis, and treatment of immunotherapy-associated cardiovascular toxicities.Cardiotoxicity is reported in patients receiving immune checkpoint inhibitors (ICI) and chimeric antigen receptor (CAR) T cell therapies. The incidence of ICI-related cardiotoxicity is above 1% and includes myocarditis, pericardial disease, arrhythmia, acute coronary syndrome, and vasculitis. The incidence of CAR T cell-associated cardiotoxicities was shown to be as high as 26% and thought to be primarily mediated by cytokine release syndrome. The presentations of cardiotoxicities are variable but are associated with significant morbidity and mortality and benefit from prompt initiation of immunosuppressive therapy. There is increasing evidence for cardiotoxicities following cancer immunotherapy. Available evidence suggests that pretreatment evaluation, close monitoring, and early intervention may reduce cardiovascular morbidity and improve outcomes in the cancer immunotherapy population

Cardiotoxicities of novel cancer immunotherapies.

Immunotherapy revolutionised oncology by harnessing the native immune system to effectively treat a wide variety of malignancies even at advanced stages. Off-target immune activation leads to immune-related adverse events affecting multiple organ systems, including the cardiovascular system. In this review, we discuss the current literature describing the epidemiology, mechanisms and proposed management of cardiotoxicities related to immune checkpoint inhibitors (ICIs), chimeric antigen receptor (CAR) T-cell therapies and bispecific T-cell engagers. ICIs are monoclonal antibody antagonists that block a co-inhibitory pathway used by tumour cells to evade a T cell-mediated immune response. ICI-associated cardiotoxicities include myocarditis, pericarditis, atherosclerosis, arrhythmias and vasculitis. ICI-associated myocarditis is the most recognised and potentially fatal cardiotoxicity with mortality approaching 50%. Recently, ICI-associated dysregulation of the atherosclerotic plaque immune response with prolonged use has been linked to early progression of atherosclerosis and myocardial infarction. Treatment strategies include immunosuppression with corticosteroids and supportive care. In CAR T-cell therapy, autologous T cells are genetically engineered to express receptors targeted to cancer cells. While stimulating an effective tumour response, they also elicit a profound immune reaction called cytokine release syndrome (CRS). High-grade CRS causes significant systemic abnormalities, including cardiovascular effects such as arrhythmias, haemodynamic compromise and cardiomyopathy. Treatment with interleukin-6 inhibitors and corticosteroids is associated with improved outcomes. The evidence shows that, although uncommon, immunotherapy-related cardiovascular toxicities confer significant risk of morbidity and mortality and benefit from rapid immunosuppressive treatment. As new immunotherapies are developed and adopted, it will be imperative to closely monitor for cardiotoxicity

Cardiotoxicities of novel cancer immunotherapies.

Immunotherapy revolutionised oncology by harnessing the native immune system to effectively treat a wide variety of malignancies even at advanced stages. Off-target immune activation leads to immune-related adverse events affecting multiple organ systems, including the cardiovascular system. In this review, we discuss the current literature describing the epidemiology, mechanisms and proposed management of cardiotoxicities related to immune checkpoint inhibitors (ICIs), chimeric antigen receptor (CAR) T-cell therapies and bispecific T-cell engagers. ICIs are monoclonal antibody antagonists that block a co-inhibitory pathway used by tumour cells to evade a T cell-mediated immune response. ICI-associated cardiotoxicities include myocarditis, pericarditis, atherosclerosis, arrhythmias and vasculitis. ICI-associated myocarditis is the most recognised and potentially fatal cardiotoxicity with mortality approaching 50%. Recently, ICI-associated dysregulation of the atherosclerotic plaque immune response with prolonged use has been linked to early progression of atherosclerosis and myocardial infarction. Treatment strategies include immunosuppression with corticosteroids and supportive care. In CAR T-cell therapy, autologous T cells are genetically engineered to express receptors targeted to cancer cells. While stimulating an effective tumour response, they also elicit a profound immune reaction called cytokine release syndrome (CRS). High-grade CRS causes significant systemic abnormalities, including cardiovascular effects such as arrhythmias, haemodynamic compromise and cardiomyopathy. Treatment with interleukin-6 inhibitors and corticosteroids is associated with improved outcomes. The evidence shows that, although uncommon, immunotherapy-related cardiovascular toxicities confer significant risk of morbidity and mortality and benefit from rapid immunosuppressive treatment. As new immunotherapies are developed and adopted, it will be imperative to closely monitor for cardiotoxicity

Immunotherapy-Associated Cardiotoxicity of Immune Checkpoint Inhibitors and Chimeric Antigen Receptor T Cell Therapy: Diagnostic and Management Challenges and Strategies.

Immunotherapies have demonstrated robust clinical efficacy in treating malignancies with increasing use and FDA approvals. We review the epidemiology, risk factors, diagnosis, and treatment of immunotherapy-associated cardiovascular toxicities.Cardiotoxicity is reported in patients receiving immune checkpoint inhibitors (ICI) and chimeric antigen receptor (CAR) T cell therapies. The incidence of ICI-related cardiotoxicity is above 1% and includes myocarditis, pericardial disease, arrhythmia, acute coronary syndrome, and vasculitis. The incidence of CAR T cell-associated cardiotoxicities was shown to be as high as 26% and thought to be primarily mediated by cytokine release syndrome. The presentations of cardiotoxicities are variable but are associated with significant morbidity and mortality and benefit from prompt initiation of immunosuppressive therapy. There is increasing evidence for cardiotoxicities following cancer immunotherapy. Available evidence suggests that pretreatment evaluation, close monitoring, and early intervention may reduce cardiovascular morbidity and improve outcomes in the cancer immunotherapy population

Novel Therapeutics for Anthracycline Induced Cardiotoxicity.

Anthracyclines remain an essential component of the treatment of many hematologic and solid organ malignancies, but has important implications on cardiovascular disease. Anthracycline induced cardiotoxicity (AIC) ranges from asymptomatic LV dysfunction to highly morbid end- stage heart failure. As cancer survivorship improves, the detection and treatment of AIC becomes more crucial to improve patient outcomes. Current treatment modalities for AIC have been largely extrapolated from treatment of conventional heart failure, but developing effective therapies specific to AIC is an area of growing research interest. This review summarizes the current evidence behind the use of neurohormonal agents, dexrazoxane, and resynchronization therapy in AIC, evaluates the clinical outcomes of advanced therapy and heart transplantation in AIC, and explores future horizons for treatment utilizing gene therapy, stem cell therapy, and mechanism-specific targets

Immune Checkpoint Therapies and Atherosclerosis: Mechanisms and Clinical&nbsp;Implications: JACC State-of-the-Art Review.

Immune checkpoint inhibitor therapy has revolutionized the treatment of advanced malignancies in recent years. Numerous reports have detailed the myriad of possible adverse inflammatory effects of immune checkpoint therapies, including within the cardiovascular system. However, these reports have been largely limited to myocarditis. The critical role of inflammation and adaptive immunity in atherosclerosis has been well characterized in preclinical studies, and several emerging clinical studies indicate a potential role of immune checkpoint targeting therapies in the development and exacerbation of atherosclerosis. In this review, we provide an overview of the role of T-cell immunity in atherogenesis and describe the molecular effects and clinical associations of both approved and investigational immune checkpoint therapy on atherosclerosis. We also highlight the role of cholesterol metabolism in oncogenesis and discuss the implications of these associations on future treatment and monitoring of atherosclerotic cardiovascular disease in the oncologic population receiving immune checkpoint therapy

Keeping immune checkpoint inhibitor myocarditis in check: advanced circulatory mechanical support as a bridge to recovery.

Immune checkpoint inhibitor (ICI)-associated myocarditis is a rare, potentially life-threatening complication of immunotherapy. We report a case of a 60-year-old female with a history of colorectal cancer treated with nivolumab immunotherapy who presented with new cardiomyopathy complicated by cardiogenic shock and ventricular arrhythmias. Treatment of ICI-associated myocarditis requires aggressive immunosuppression and supportive therapy. In this case, the patient required advanced mechanical circulatory support as a bridge to recovery. This case highlights the complexity of diagnosis, haemodynamic management, and treatment of fulminant ICI myocarditis

Blood Accessibility to Fibrin in Venous Thrombosis is Thrombus Age-Dependent and Predicts Fibrinolytic Efficacy: An In Vivo Fibrin Molecular Imaging Study

Fibrinolytic therapy of venous thromboembolism (VTE) is increasingly utilized, yet limited knowledge is available regarding in vivo mechanisms that govern fibrinolytic efficacy. In particular, it is unknown how age-dependent thrombus organization limits direct blood contact with fibrin, the target of blood-based fibrinolytic agents. Utilizing high-resolution in vivo optical molecular imaging with FTP11, a near-infrared fluorescence (NIRF) fibrin-specific reporter, here we investigated the in vivo interrelationships of blood accessibility to fibrin, thrombus age, thrombus neoendothelialization, and fibrinolysis in murine venous thrombosis (VT). In both stasis VT and non-stasis VT, NIRF microscopy showed that FTP11 fibrin binding was thrombus age-dependent. FTP11 localized to the luminal surface of early-stage VT, but only minimally to subacute VT (p<0.001). Transmission electron microscopy of early stage VT revealed direct blood cell contact with luminal fibrin-rich surfaces. In contrast, subacute VT exhibited an encasing CD31+ neoendothelial layer that limited blood cell contact with thrombus fibrin in both VT models. Next we developed a theranostic strategy to predict fibrinolytic efficacy based on the in vivo fibrin accessibility to blood NIRF signal. Mice with variably aged VT underwent FTP11 injection and intravital microscopy (IVM), followed by tissue plasminogen activator infusion to induce VT fibrinolysis. Fibrin molecular IVM revealed that early stage VT, but not subacute VT, bound FTP11 (p<0.05), and experienced higher rates of fibrinolysis and total fibrinolysis (p<0.05 vs. subacute VT). Before fibrinolysis, the baseline FTP11 NIRF signal predicted the net fibrinolysis at 60 minutes (p<0.001). Taken together, these data provide novel insights into the temporal evolution of VT and its susceptibility to therapeutic fibrinolysis. Fibrin molecular imaging may provide a theranostic strategy to identify venous thrombi amenable to fibrinolytic therapies