Hypertension Severity and Declines in Left Ventricular Ejection Fraction Among Women Receiving Adjuvant Chemotherapy for Breast Cancer (WF-97415 UPBEAT).

BACKGROUND: Hypertension is a risk factor for experiencing left ventricular ejection fraction (LVEF) declines during receipt of potentially cardiotoxic breast cancer (BC) treatment. We sought to determine whether the hypertension stage is associated with LVEF decline during BC treatment. METHODS: Across 24 centers, cardiac magnetic resonance measures of LVEF and brachial arterial blood pressure (BP) measurements were performed in women with stages I to III BC before and 3 months after initiating potentially cardiotoxic chemotherapy. Using multivariable analysis, we assessed in a blinded fashion the association between 3-month ΔLVEF and precancer treatment American Heart Association/American College of Cardiology stages of hypertension. RESULTS: Among 204 women, age averaged 56±1 years with 75% being White and 20% of Black race. Participants received anthracycline (45.6%), trastuzumab (22.5%), cyclophosphamide (52.9%), or paclitaxel (50%). After accounting for pretreatment LVEF, diabetes status, tobacco use, age, the number of antihypertensive medications, and body mass index, those with stage II hypertension experienced an LVEF decline of -2.89% ([95% CI, -0.69% to -5.19%]; P=0.01) relative to individuals with normal BP. Other stages saw nonsignificant declines relative to normal BP to elevated BP (-1.63% [95% CI, -0.62% to 3.88%]; P=0.16) and stage I hypertension (-0.94% [95% CI, -0.90% to 2.78%]; P=0.32). CONCLUSIONS: Compared with women receiving treatment for BC with normal BP, there is a stronger association of decline in LVEF in women with stage II hypertension relative to women with other hypertension stages. This raises the possibility that stage along with hypertension presence may be associated with an increased risk for the LVEF decline among women receiving potentially cardiotoxic chemotherapy for BC. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02791581 and NCT01719562.

Long-term QT prolongation in monkeys after doxorubicin administration at doses similar to breast cancer therapy.

Background: Studies in small animals and human patients have suggested that anthracyclines may prolong cardiac repolarization, or at least inhibit repolarization reserve, predisposing to QT prolongation and dangerous arrhythmias such as Torsades de pointes. This association in humans is difficult to confirm due to multiple confounding variables such as the presence of other medications and concurrent illness. Objectives: Identify a long-term association between anthracycline administration and repolarization prolongation in nonhuman primates, which can be measured as prolonged QT/QTc intervals on surface electrocardiogram. Methods: Five female African Green monkeys (AGMs) aged 13 ± 1 years received Doxorubicin (Dox) at doses similar to women treated for breast cancer (30-60 mg/m2/biweekly IV, total cumulative dose: 240 mg/m2) and underwent 12-lead electrocardiogram (ECG) before and 15 weeks after the final dose of Dox treatment. A blinded paired analysis was performed on ECG derived heart rate (HR), QRS, QT and QT corrected for HR (QTc) interval durations. Results: After Dox, all monkeys exhibited increased QT (BL: 323.2 ± 27.4 ms vs. Post-Dox: 366.4 ± 18.7 ms, p = 0.002) and QTc (BL: 440.2 ± 22.8 ms vs. Post-Dox: 500.8 ± 22.0 ms, p = 0.009) intervals, without any significant changes in HR or QRS duration (p = 0.92 and p = 0.47 respectively). Conclusions: AGMs treated with Dox exhibited long-term QT and QTc prolongation, along with the expected cardiotoxicity (LVEF decrease). While similar findings were shown in small animal studies, confounders make human association difficult to prove. Our finding provides a valuable intermediary step, showing direct effect of Dox on repolarization in nonhuman primates.

Myocardial Elasticity Imaging Correlates with Histopathology in a Model of Anthracycline-Induced Cardiotoxicity.

Background: There is considerable focus on developing strategies for identifying subclinical cardiac decline prior to cardiac failure. Myocardial tissue elasticity changes may precede irreversible cardiac damage, providing promise for an early biomarker for cardiac decline. Biomarker strategies are of particular interest in cardio-oncology due to cardiotoxic effects of anti-neoplastic therapies, particularly anthracycline-based chemotherapeutics. Current clinical methods for diagnosing cardiotoxicity are too coarse to identify cardiac decline early enough for meaningful therapeutic intervention, or too cumbersome for clinical implementation. Methods: Utilizing changes in myocardial elasticity as a biomarker for subclinical cardiac decline, we developed a biomechanical model-based elasticity imaging methodology (BEIM) to estimate spatial maps of left ventricle (LV) myocardial elasticity. In this study, we employ this methodology to assess changes in LV elasticity in a non-human primate model of doxorubicin-induced cardiotoxicity. Cardiac magnetic resonance imaging of five African Green monkeys was acquired at baseline prior to doxorubicin administration, 6-weeks, and 15-weeks after final doxorubicin dose and histopathological samples of the LV were taken at 15-weeks after final doxorubicin dose. Spatial elasticity maps of the mid-short axis plane of the LV were estimated at each image acquisition. Global and regional LV elasticity were calculated and changes between imaging time points was assessed. LV elasticity at baseline and final time point were compared to cardiomyocyte size and collagen volume fraction measurements calculated from histopathological staining of archived tissue bank samples and study endpoint tissue samples utilizing Pearson's correlation coefficients. Results: We identify significant changes in LV elasticity between each imaging time point both globally and regionally. We also demonstrate strong correlation between LV elasticity and cardiomyocyte size and collagen volume fraction measurements. Results indicate that LV elasticity estimates calculated using BEIM correlate with histopathological changes that occur due to doxorubicin administration, validating LV elasticity solutions and providing significant promise for use of BEIM to non-invasively elucidate cardiac injury. Conclusions: This methodology can show progressive changes in LV elasticity and has potential to be a more sensitive indicator of elasticity changes than current clinical measures of cardiotoxicity. LV elasticity may provide a valuable biomarker for cardiotoxic effects of anthracycline-based chemotherapeutics and cardiac disease detection.

Replacement substance P reduces cardiac fibrosis in monkeys with type 2 diabetes.

BACKGROUND: Type 2 diabetes mellitus (T2DM)-associated cardiac fibrosis contributes to heart failure. We previously showed that diabetic mice with cardiomyopathy, including cardiac fibrosis, exhibit low levels of the neuropeptide substance P; exogenous replacement of substance P reversed cardiac fibrosis, independent of body weight, blood glucose and blood pressure. We sought to elucidate the effectiveness and safety of replacement substance P to ameliorate or reverse cardiac fibrosis in type 2 diabetic monkeys. METHODS: Four female T2DM African Green monkeys receive substance P (0.5 mg/Kg/day S.Q. injection) for 8 weeks. We obtained cardiac magnetic resonance imaging and blood samples to assess left ventricular function and fibrosis by T1 map-derived extracellular volume as well as circulating procollagen type I C-terminal propeptide. Hematological parameters for toxicities were also assessed in these monkeys and compared with three female T2DM monkeys receiving saline S.Q. as a safety comparison group. RESULTS: Diabetic monkeys receiving replacement substance P exhibited a ∼20% decrease in extracellular volume (p = 0.01), concomitant with ∼25% decrease procollagen type I C-terminal propeptide levels (p = 0.008). Left ventricular ejection fraction was unchanged with substance P (p = 0.42); however, circumferential strain was improved (p < 0.01). Complete blood counts, glycosylated hemoglobin A1c, lipids, liver and pancreatic enzymes, and inflammation markers were unchanged (p > 0.05). CONCLUSIONS: Replacement substance P reversed cardiac fibrosis in a large preclinical model of type 2 diabetes, independent of glycemic control. No hematological or organ-related toxicity was associated with replacement substance P. These results strongly support a potential application for replacement substance P as safe therapy for diabetic cardiac fibrosis.

NLRP3-mediated inflammation in cardio-oncology: sterile yet harmful.

Despite significant advances and the continuous development of novel, effective therapies to treat a variety of malignancies, cancer therapy-induced cardiotoxicity has been identified as a prominent cause of morbidity and mortality, closely competing with secondary malignancies. This unfortunate limitation has prompted the inception of the field of cardio-oncology with its purpose to provide the necessary knowledge and key information on mechanisms that support the use of the most efficacious cancer therapy with minimal or no interruption while paying close attention to preventing cardiovascular related morbidity and mortality. Several mechanisms that contribute to cancer therapy-induced cardiotoxicity have been proposed and studied. These mainly involve mitochondrial dysfunction and reactive oxygen species-induced oxidative stress, lysosomal damage, impaired autophagy, cell senescence, DNA damage, and sterile inflammation with the formation and activation of the NLRP3 inflammasome. In this review, we focus on describing the principal mechanisms for different classes of cancer therapies that lead to cardiotoxicity involving the NLRP3 inflammasome. We also summarize current evidence of cardio-protection with inflammasome inhibitors in the context of heart disease in general, and further highlight the potential application of this evidence for clinical translation in at risk patients for the purpose of preventing cancer therapy associated cardiovascular morbidity and mortality.

Eicosapentaenoic Acid Ameliorates Cardiac Fibrosis and Tissue Inflammation in Spontaneously Hypertensive Rats.

Hypertension affects 1 in 3 adults in the United States and leads to left ventricular (LV) concentric hypertrophy, interstitial fibrosis, and increased stiffness. The treatment of cardiac fibrosis remains challenging and empiric. Eicosapentaenoic acid (EPA) is an omega-3 polyunsaturated fatty acid that is highly effective in reducing cardiovascular events in patients and cardiac fibrosis and hypertrophy in animals when administered before pressure overload by promoting the increase of anti-inflammatory M1 macrophages. In this study, we investigated whether EPA mitigates the exacerbation of cardiac remodeling and fibrosis induced by established hypertension, a situation that closely recapitulates a clinical scenario. Twelve-week-old spontaneously hypertensive rats were randomized to eat an EPA-enriched or control diet for 20 weeks. We report that rats eating the EPA-enriched diet exhibited a reduction of interstitial cardiac fibrosis and ameliorated LV diastolic dysfunction despite the continuous increase in blood pressure. However, we found that EPA did not have an impact on cardiac hypertrophy. Interestingly, the EPA diet increased mRNA expression of M2 macrophage marker Mrc1 and interleukin-10 in cardiac tissue. These findings indicated that the antifibrotic effects of EPA are mediated in part by phenotypic polarization of macrophages toward anti-inflammatory M2 macrophages and increases of the anti-inflammatory cytokine, interleukin-10. In summary, EPA prevents the exacerbation of cardiac fibrosis and LV diastolic dysfunction during sustained pressure overload. EPA could represent a novel treatment strategy for hypertensive cardiomyopathy.

Replacement of Lost Substance P Reduces Fibrosis in the Diabetic Heart by Preventing Adverse Fibroblast and Macrophage Phenotype Changes.

Reduced levels of the sensory nerve neuropeptide substance P (SP) have been reported in the diabetic rat heart, the consequence being a loss of cardioprotection in response to ischemic post-conditioning. We considered whether this loss of SP also predisposes the heart to non-ischemic diabetic cardiomyopathy in the form of fibrosis and hypertrophy. We report that diabetic Leprdb/db mice have reduced serum SP and that administration of exogenous replacement SP ameliorated cardiac fibrosis. Cardiac hypertrophy did not occur in Leprdb/db mice. Cardiac fibroblasts exposed to high glucose converted to a myofibroblast phenotype and produced excess extracellular matrix proteins; this was prevented by the presence of SP in the culture media. Cardiac fibroblasts exposed to high glucose produced increased amounts of the receptor for advanced glycation end products, reactive oxygen species and inflammatory cytokines, all of which were prevented by SP. Cultured macrophages assumed an M1 pro-inflammatory phenotype in response to high glucose as indicated by increased TNF-α, CCL2, and IL-6. SP promoted a shift to the reparative M2 macrophage phenotype characterized by arginase-1 and IL-10. Leprdb/db mice showed increased left ventricular M1 phenotype macrophages and an increase in the M1/M2 ratio. Replacement SP in Leprdb/db mice restored a favorable M1 to M2 balance. Together these findings indicate that a loss of SP predisposes the diabetic heart to developing fibrosis. The anti-fibrotic actions of replacement SP involve direct effects on cardiac fibroblasts and macrophages to oppose adverse phenotype changes. This study identifies the potential of replacement SP to treat diabetic cardiomyopathy.

The Role of Cardiac MRI in Animal Models of Cardiotoxicity: Hopes and Challenges.

Animal models of chemotherapy-induced cardiotoxicity have been instrumental in understanding the underlying mechanisms of the disease. The use of cardiac magnetic resonance (CMR) imaging and nuclear magnetic resonance (NMR) imaging in preclinical models allows the non-invasive study of subclinical pathophysiological processes that influence cardiac function and establish imaging parameters that can be adopted into clinical practice to predict cardiovascular outcomes. Given the rising population of cancer survivors and the current lack of effective therapies for the management of cardiotoxicity, research combining clinically relevant animal models and non-invasive cardiac imaging remains essential to improve methods to monitor, predict, and treat cardiovascular adverse events. This comprehensive review summarizes the lessons learned from animal models of cardiotoxicity employing CMR and tissue characterization techniques and discusses the ongoing challenges and hopes for the future.

Simultaneous Left Ventricular Volume and Strain Changes During Chemotherapy Associate With 2-Year Postchemotherapy Measures of Left Ventricular Ejection Fraction.

Background Although changes in left ventricular end-systolic volume (LVESV), left ventricular end-diastolic volume, and global circumferential strain occur during cancer treatment, the relationship of these changes to the 2-year post-cancer-treatment measures of left ventricular ejection fraction (LVEF) are unknown. Methods and Results In a prospective, continuously recruited cohort of 95 patients scheduled to receive potentially cardiotoxic chemotherapy for breast cancer, lymphoma, or soft tissue sarcoma, measures of left ventricular end-diastolic volume, LVESV, global circumferential strain, and LVEF were acquired via cardiac magnetic resonance imaging before and then 3 and 24 months after initiating treatment by individuals blinded to all patient identifiers. Participants had an average age of 54±15 years; 68% were women, and 82% were of white race. LVEF declined from 62±7% to 58±9% over the 24 months (P<0.0001), with 42% of participants experiencing a >5% decline in LVEF at 24 months. Predictors of a 24-month >5% decline in LVEF included the following factors from baseline to 3 months into treatment: (1) >3-mL increases in LVESV (P=0.033), (2) >3-mL increases in LVESV or 10-mL declines in left ventricular end-diastolic volume with little change in LVESV (P=0.001), or (3) ≥10% deteriorations in global circumferential strain with little change in LVESV (P=0.036). Conclusion During receipt of potentially cardiotoxic chemotherapy, increases in LVESV, the absence of its deterioration during decreases of left ventricular end-diastolic volume, or the deterioration of global circumferential strain without a marked decrease in LVESV help identify those who will develop more permanent 2-year declines in LVEF.

Doxorubicin-Induced Myocardial Fibrosis Involves the Neurokinin-1 Receptor and Direct Effects on Cardiac Fibroblasts.

BACKGROUND: Cancer patients receiving anthracycline-based chemotherapy (Anth-bC) may experience early cardiac fibrosis, which could be an important contributing mechanism to the development of impaired left ventricular (LV) function. Substance P, a neuropeptide that predominantly acts via the neurokinin 1 receptor (NK-1R), contributes to adverse myocardial remodelling and fibrosis in other cardiomyopathies. We sought to determine if NK-1R blockade is effective against doxorubicin (Dox - a frequently used Anth-bC)-induced cardiac fibrosis and cardiomyocyte apoptosis. In addition, we explored the direct effects of Dox on cardiac fibroblasts. METHODS: Male Sprague-Dawley rats were randomised to receive saline, six cycles of Dox (1.5mg Dox/kg/cycle) or Dox with an NK-1R antagonist (L732138, 5mg/kg/daily through Dox treatment). At 8 weeks after the initial dose of Dox, LV function and histopathological myocardial fibrosis and cell apoptosis were assessed. Collagen secretion was measured in vitro to test direct Dox activation of cardiac fibroblasts. RESULTS: Rats undergoing Dox treatment (9mg/kg cumulative dose) developed cardiac fibrosis and cardiomyocyte apoptosis. NK-1R blockade partially mitigated cardiac fibrosis while completely preventing cardiomyocyte apoptosis. This resulted in improved diastolic function. Furthermore, we found that Dox had direct effects on cardiac fibroblasts to cause increased collagen production and enhanced cell survival. CONCLUSIONS: This study demonstrates that cardiac fibrosis induced by Anth-bC can be reduced by NK-1R blockade. The residual fibrotic response is likely due to direct Dox effects on cardiac fibroblasts to produce collagen.

Frequency of Transition From Stage A to Stage B Heart Failure After Initiating Potentially Cardiotoxic Chemotherapy.

OBJECTIVES: This study sought to determine the prevalence of American Heart Association/American College of Cardiology Foundation (AHA/ACCF) heart failure (HF) stages after potentially cardiotoxic chemotherapy was initiated. BACKGROUND: For individuals receiving potentially cardiotoxic chemotherapy, the frequency of transitioning from Stage A to more advanced HF stages is not well described. METHODS: In 143 Stage A HF patients with breast cancer, lymphoma and leukemia, renal cell carcinoma, or sarcoma prior to and then at 3, 6, and 12 to 24 months after potentially cardiotoxic chemotherapy was initiated, we obtained blinded cardiac magnetic resonance measurements of left ventricular ejection fraction (LVEF). RESULTS: Three months after potentially cardiotoxic chemotherapy was initiated, 18.9% of patients transitioned from Stage A to Stage B HF. A total of 83% and 80% of patients with Stage A HF at 3 months, respectively, exhibited Stage A HF at 6 and 12 to 24 months; 68% and 56% of those with Stage B HF at 3 months, respectively, exhibited Stage B HF at 6 and 12 to 24 months (p < 0.0001 and p = 0.026, respectively). CONCLUSIONS: Transitioning from Stage A to Stage B or remaining in Stage A HF 3 months after potentially cardiotoxic chemotherapy was initiated relates to longer-term (6 to 24 months post-treatment) assessments of HF stage.

Left Ventricular Mass Change After Anthracycline Chemotherapy.

BACKGROUND: Myocardial atrophy and left ventricular (LV) mass reductions are associated with fatigue and exercise intolerance. The relationships between the receipt of anthracycline-based chemotherapy (Anth-bC) and changes in LV mass and heart failure (HF) symptomatology are unknown, as is their relationship to LV ejection fraction (LVEF), a widely used measurement performed in surveillance strategies designed to avert symptomatic HF associated with cancer treatment. METHODS AND RESULTS: We performed blinded, serial assessments of body weight, LVEF and mass, LV-arterial coupling, aortic stiffness, and Minnesota Living with Heart Failure Questionnaire measures before and 6 months after initiating Anth-bC (n=61) and non-Anth-bC (n=15), and in 24 cancer-free controls using paired t and χ2 tests and multivariable linear models. Participants averaged 51±12 years, and 70% were women. Cancer diagnoses included breast cancer (53%), hematologic malignancy (42%), and soft tissue sarcoma (5%). We observed a 5% decline in both LVEF (P<0.0001) and LV mass (P=0.03) in the setting of increased aortic stiffness and disrupted ventricular-arterial coupling in those receiving Anth-bC but not other groups (P=0.11-0.92). A worsening of the Minnesota Living with Heart Failure Questionnaire score in Anth-bC recipients was associated with myocardial mass declines (r=-0.27; P<0.01) but not with LVEF declines (r=0.11; P=0.45). Moreover, this finding was independent of LVEF changes and body weight. CONCLUSIONS: Early after Anth-bC, LV mass reductions associate with worsening HF symptomatology independent of LVEF. These data suggest an alternative mechanism whereby anthracyclines may contribute to HF symptomatology and raise the possibility that surveillance strategies during Anth-bC should also assess LV mass.

Combination of anthracyclines and anti-CD47 therapy inhibit invasive breast cancer growth while preventing cardiac toxicity by regulation of autophagy.

BACKGROUND: A perennial challenge in systemic cytotoxic cancer therapy is to eradicate primary tumors and metastatic disease while sparing normal tissue from off-target effects of chemotherapy. Anthracyclines such as doxorubicin are effective chemotherapeutic agents for which dosing is limited by development of cardiotoxicity. Our published evidence shows that targeting CD47 enhances radiation-induced growth delay of tumors while remarkably protecting soft tissues. The protection of cell viability observed with CD47 is mediated autonomously by activation of protective autophagy. However, whether CD47 protects cancer cells from cytotoxic chemotherapy is unknown. METHODS: We tested the effect of CD47 blockade on cancer cell survival using a 2-dimensional high-throughput cell proliferation assay in 4T1 breast cancer cell lines. To evaluate blockade of CD47 in combination with chemotherapy in vivo, we employed the 4T1 breast cancer model and examined tumor and cardiac tissue viability as well as autophagic flux. RESULTS: Our high-throughput screen revealed that blockade of CD47 does not interfere with the cytotoxic activity of anthracyclines against 4T1 breast cancer cells. Targeting CD47 enhanced the effect of doxorubicin chemotherapy in vivo by reducing tumor growth and metastatic spread by activation of an anti-tumor innate immune response. Moreover, systemic suppression of CD47 protected cardiac tissue viability and function in mice treated with doxorubicin. CONCLUSIONS: Our experiments indicate that the protective effects observed with CD47 blockade are mediated through upregulation of autophagic flux. However, the absence of CD47 in did not elicit a protective effect in cancer cells, but it enhanced macrophage-mediated cancer cell cytolysis. Therefore, the differential responses observed with CD47 blockade are due to autonomous activation of protective autophagy in normal tissue and enhancement immune cytotoxicity against cancer cells.