Beta-Blockers for Primary Prevention of Anthracycline Cardiotoxicity

Inhibition of Cyp1a Protects Mice against Anthracycline Cardiomyopathy

Background

Anthracyclines such as doxorubicin (Dox) are highly effective anti-tumor agents, but their use is limited by dose-dependent cardiomyopathy and heart failure. Our laboratory previously reported that induction of cytochrome P450 family 1 (Cyp1) enzymes contributes to acute Dox cardiotoxicity in zebrafish and in mice, and that potent Cyp1 inhibitors prevent cardiotoxicity. However, the role of Cyp1 enzymes in chronic Dox cardiomyopathy, as well as the mechanisms underlying cardioprotection associated with Cyp1 inhibition, have not been fully elucidated.

Methods

The Cyp1 pathway was evaluated using a small molecule Cyp1 inhibitor in wild-type (WT) mice, or Cyp1-null mice ( Cyp1a1/1a2 -/- , Cyp1b1 -/- , and Cyp1a1/1a2/1b1 -/- ). Low-dose Dox was administered by serial intraperitoneal or intravenous injections, respectively. Expression of Cyp1 isoforms was measured by RT-qPCR, and myocardial tissue was isolated from the left ventricle for RNA sequencing. Cardiac function was evaluated by transthoracic echocardiography.

Results

In WT mice, Dox treatment was associated with a decrease in Cyp1a2 and increase in Cyp1b1 expression in the heart and in the liver. Co-treatment of WT mice with Dox and the novel Cyp1 inhibitor YW-130 protected against cardiac dysfunction compared to Dox treatment alone. Cyp1a1/1a2 -/- and Cyp1a1/1a2/1b1 -/- mice were protected from Dox cardiomyopathy compared to WT mice. Male, but not female, Cyp1b1 -/- mice had increased cardiac dysfunction following Dox treatment compared to WT mice. RNA sequencing of myocardial tissue showed upregulation of Fundc1 and downregulation of Ccl21c in Cyp1a1/1a2 -/- mice treated with Dox, implicating changes in mitophagy and chemokine-mediated inflammation as possible mechanisms of Cyp1a-mediated cardioprotection.

Conclusions

Taken together, this study highlights the potential therapeutic value of Cyp1a inhibition in mitigating anthracycline cardiomyopathy.

Genetics of Anthracycline-Associated Cardiotoxicity

Anthracyclines are a major component of chemotherapies used in many pediatric and adult malignancies. Anthracycline-associated cardiotoxicity (ACT) is a dose-dependent adverse effect that has substantial impact on morbidity and mortality. Therefore, the identification of genetic variants associated with increased risk of ACT has the potential for significant clinical impact to improve patient care. The goal of this review is to summarize the current evidence supporting genetic variants associated with ACT, identify gaps and limitations in current knowledge, and propose future directions for incorporating genetics into clinical practice for patients treated with anthracyclines. We will discuss mechanisms of ACT that could be illuminated by genetics and discuss clinical applications for the cardiologist/cardio-oncologist.

Role of cardioprotective agents on chemotherapy-induced heart failure: A systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Although previous clinical randomized controlled trials (RCTs) have tested the effect of a variety of cardioprotective agents on cancer therapy-induced cardiotoxicity, the number of included patients was limited, and the results remained controversial. In this study, we aimed to evaluate the preventive or therapeutic effects of cardioprotective agents on heart failure (HF) caused by cardiotoxicity induced by cancer therapy.

METHODS

We included trials of the following cardioprotective drugs: Angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, beta-blockers, aldosterone antagonists and stains. We extracted the relevant information with predefined data extraction forms, and assessed the risk of bias in randomized controlled trials with the Cochrane risk of bias tool. The primary outcome was the left ventricular ejection fraction of patients after chemotherapy. We used the random-effects model to carry out pair-wise meta-analysis, and then carry out the random-effects network meta-analysis within the Bayesian framework.

RESULTS

Twenty-two relevant RCTs, including 1 916 patients (79.6 % women) with a mean age of 48.4 years, were included. Based on the evaluation of all drug species from 20 studies (26 comparisons), the analysis found that 4 therapies, aldosterone antagonists (MD, 12.78 [95 % CI, 2.87-22.69] and MD, 13.75 [95 % CI, 2.21-25.30]), ACEIs (MD, 6.79 [95 % CI, 2.11-11.48] and MD, 7.76 [95 % CI, 2.64-12.88]), statin (MD, 8.35 [95 % CI, 1.11-15.59]), and beta-blockers (MD, 4.00 [95 % CI, 0.87-7.14]), had a higher efficacy than placebo and/or control, suggesting an LVEF protective effect of cardioprotective therapy. In the analysis classified by single drug or drug combination, based on 22 studies (31 comparisons), spironolactone (MD, 12.77 [95 % CI, 1.76-23.79] and MD, 14.62 [95 % CI, 1.70-27.55]), a combination of candesartan and carvedilol (MD, 12.40 [95 % CI, 0.99-23.81]), enalapril (MD, 7.35 [95 % CI, 1.16-13.54] and MD, 9.20 [95 % CI, 2.61-15.79]), and statin (MD, 8.36 [95 % CI, 0.36-16.36]) showed significant benefits in protecting left ventricular (LV) systolic function compared with the placebo and/or control.

CONCLUSION

When classified according to drug type, aldosterone antagonists, ACEIs, statins, and beta-blockers could substantially improve the LV systolic function. In the analysis classified by single drug or drug combination, spironolactone, enalapril, and statin have a significant cardioprotective effect. However, ARBs have no cardioprotective effect and fail to improve the LVEF.