NAD+ supplementation improves cardiomyocyte resilience to doxorubicin-induced cardiotoxicity

Introduction The number of cancer survivors has markedly increased in recent years, bringing greater attention to cancer therapy-related therapy related to cardiac dysfunction (CTRCD). Anthracyclines, such as doxorubicin (DOXO), are widely used chemotherapeutics but are well known to induce oxidative stress, mitochondrial dysfunction, and premature cardiomyocyte senescence. A decline in nicotinamide adenine dinucleotide (NAD⁺), a critical cofactor for mitochondrial function, DNA repair, and antioxidant defense, has been implicated in the exacerbatione of cardiomyocyte vulnerability following anthracycline exposure. Despite the growing interest, the molecular mechanisms underlying anthracycline cardiotoxicity remain incompletely understood, and effective preventive strategies are lacking. Methods Single-nucleus RNA sequencing was performed on human cardiac tissue to define cardiomyocyte transcriptional responses associated with oxidative stress and senescence. These findings were complemented by an in vitro cardiotoxicity model in which cardiomyocytes were exposed to DOXO, with or without NAD⁺ supplementation. Cellular viability, oxidative stress, mitochondrial function, and senescencemarkers markers of senescence were systematically assessed. Results DOXO exposure induced transcriptional programs consistent with oxidative stress, impaired mitochondrial metabolism, and cellular senescence in human cardiomyocytes, accompanied by a significant reduction in NAD⁺-dependent pathways. NAD⁺ supplementation preserved cardiomyocyte viability, reduced oxidative stress, enhanced cellular resilience, and attenuated senescence-associated phenotypes in vitro. Mechanistically, NAD⁺ restoration improved antioxidant capacity and activated anti-aging pathways, thereby mitigating the deleterious effects of anthracycline treatment on cardiac myocytes. Conclusion Our findings identify NAD⁺ depletion as a key contributor to anthracycline-induced cardiotoxicity and demonstrate that NAD⁺ supplementation confers robust cardioprotective effects in mice. These results suggest that NAD⁺ supplementation represents a promising nutritional or therapeutic strategy to enhance endogenous antioxidant defenses, delay myocardial aging, and preserve cardiac function in cancer survivors exposed to anthracycline therapy.