Remote ischaemic preconditioning ameliorates anthracycline-induced cardiotoxicity and preserves mitochondrial integrity

Abstract

Aims Anthracycline-induced cardiotoxicity (AIC) is a serious adverse effect among cancer patients. A central mechanism of AIC is irreversible mitochondrial damage. Despite major efforts, there are currently no effective therapies able to prevent AIC. Methods and Results Forty Large-White pigs were included. In Study 1, 20 pigs were randomized 1:1 to remote ischemic pre-conditioning (RIPC, 3 cycles of 5 min leg ischemia followed by 5 min reperfusion) or no pretreatment. RIPC was performed immediately before each intracoronary doxorubicin injections (0.45 mg/kg) given at weeks 0, 2, 4, 6, and 8. A group of 10 pigs with no exposure to doxorubicin served as healthy controls. Pigs underwent serial cardiac magnetic resonance (CMR) exams at baseline and at weeks 6, 8, 12, and 16, being sacrifice after that. In study 2, 10 new pigs received 3 doxorubicin injections (with/out preceding RIPC) and were sacrificed at week 6. In Study 1, LVEF depression was blunted animals receiving RIPC before doxorubicin (RIPC-Doxo), which had a significantly higher LVEF at week 16 than doxorubicin treated pigs that received no pretreatment (Untreated-Doxo) (41.5±9.1% vs 32.5±8.7%, p = 0.04). It was mainly due to conserved regional contractile function. In Study 2, transmission electron microscopy (TEM) at week 6 showed fragmented mitochondria with severe morphological abnormalities in Untreated-Doxo pigs, together with upregulation of fission and autophagy proteins. At the end of the 16-week Study 1 protocol, TEM revealed overt mitochondrial fragmentation with structural fragmentation in Untreated-Doxo pigs, whereas interstitial fibrosis was less severe in RIPC+Doxo pigs. Conclusion In a translatable large animal model of AIC, RIPC applied immediately before each doxorubicin injection resulted in preserved cardiac contractility with significantly higher long-term LVEF and less cardiac fibrosis. RIPC prevented mitochondrial fragmentation and dysregulated autophagy from AIC early stages. RIPC is a promising intervention for testing in clinical trials in AIC. Translational perspective Serial cardiac magnetic resonance (CMR) evaluation of a highly translatable large animal model of anthracycline-induced cardiotoxicity (AIC) shows that cumulative exposure to doxorubicin results in significantly reduced LVEF and extensive mitochondrial fragmentation. Remote ischemic preconditioning (RIPC) applied before each doxorubicin cycle preserved cardiac contractility and LVEF in long-term CMR exams. RIPC prevented doxorubicin-induced irreversible mitochondrial fragmentation and dysregulated autophagy. RIPC is as an attractive strategy for testing in clinical trials in AIC.

Progress in cardiac research: from rebooting cardiac regeneration to a complete cell atlas of the heart

“…Galan-Arriola et al . 62 performed a study of anthracycline-induced cardiotoxicity in pigs and showed that cumulative exposure to doxorubicin significantly reduced LV ejection fraction and extensive mitochondrial fragmentation. Remote ischemic preconditioning (RIPC) applied before each doxorubicin cycle preserved cardiac contractility and LV ejection fraction in long-term cardiac MRI exams.…”

Extracellular matrix remodeling in animal models of anthracycline-induced cardiomyopathy: a meta-analysis

“…Galán-Arriola et al studied pigs with doxorubicin-induced cardiomyopathy (mean LVEF 32.5%, cumulative dose 2.25 mg/kg) and found a significant increase compared to healthy controls in mitochondrial fragmentation and in interstitial fibrosis area at ±1.0 human equivalent years [ 25 ].…”

Atg5 knockdown induces age-dependent cardiomyopathy which can be rescued by repeated remote ischemic conditioning

“…These findings are consistent with our previous reports showing that RIC increases autophagy signaling in several different models [ 25 , 26 , 47 – 49 ]. However, in some reports, albeit in different models with different RIC protocols (in large animals subjected to intracoronary doxorubicin infusion [ 31 ], an acute human cardiac surgical intraoperative study [ 32 ] and doxorubicin toxicity in a mouse model [ 33 ]) have shown that RIC has no effect or even decreases autophagy signaling, emphasizing the need for disease-specific models in regard to the effects of RIC. Nonetheless, it is well known that impaired autophagy is associated with a variety of human diseases [ 3 ] including cardiovascular diseases.…”

“…These factors are clearly less relevant in preclinical experiments with animals, and such factors may not be at play in younger patients with different therapeutic profiles and comorbities. Children and young adults with inherited cardiomyopathies, or toxin-related cardiomyopathy may fall into such a category and we, and others, have shown promising effects of RIC in experimental models of LPS-induced myocardial dysfunction [ 24 ], and Doxorubicin-induced cardiomyopathy [ 25 , 31 , 32 ], for example.…”