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Background: Anthracycline-induced heart failure has been traditionally attributed to direct iron-catalyzed oxidative damage. Dexrazoxane (DEX)-the only drug approved for its prevention-has been believed to protect the heart via its iron-chelating metabolite ADR-925. However, direct evidence is lacking, and recently proposed TOP2B (topoisomerase II beta) hypothesis challenged the original concept.
Methods: Pharmacokinetically guided study of the cardioprotective effects of clinically used DEX and its chelating metabolite ADR-925 (administered exogenously) was performed together with mechanistic experiments. The cardiotoxicity was induced by daunorubicin in neonatal ventricular cardiomyocytes in vitro and in a chronic rabbit model in vivo (n=50).
Results: Intracellular concentrations of ADR-925 in neonatal ventricular cardiomyocytes and rabbit hearts after treatment with exogenous ADR-925 were similar or exceeded those observed after treatment with the parent DEX. However, ADR-925 did not protect neonatal ventricular cardiomyocytes against anthracycline toxicity, whereas DEX exhibited significant protective effects (10-100 µmol/L; <0.001). Unlike DEX, ADR-925 also had no significant impact on daunorubicin-induced mortality, blood congestion, and biochemical and functional markers of cardiac dysfunction in vivo (eg, end point left ventricular fractional shortening was 32.3±14.7%, 33.5±4.8%, 42.7±1.0%, and 41.5±1.1% for the daunorubicin, ADR-925 [120 mg/kg]+daunorubicin, DEX [60 mg/kg]+daunorubicin, and control groups, respectively; <0.05). DEX, but not ADR-925, inhibited and depleted TOP2B and prevented daunorubicin-induced genotoxic damage. TOP2B dependency of the cardioprotective effects was probed and supported by experiments with diastereomers of a new DEX derivative.
Conclusions: This study strongly supports a new mechanistic paradigm that attributes clinically effective cardioprotection against anthracycline cardiotoxicity to interactions with TOP2B but not metal chelation and protection against direct oxidative damage.
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http://dx.doi.org/10.1161/CIRCHEARTFAILURE.120.008209 | DOI Listing |
J Physiol
September 2025
Department of Cell and Molecular Biology, University of Hawaii, Honolulu, HI, USA.
Diagnoses of prediabetes and metabolic syndromes, such as metabolic-associated steatotic liver disease (MASLD), are increasing at an alarming rate worldwide, often simultaneously. A significant consequence of these is high risk of cardiovascular disease, highlighting the need for cardiac-specific therapeutics for intervention during the prediabetic stage. Recent studies have demonstrated that chemogenetic activation of the cardiac parasympathetic system through hypothalamic oxytocin (OXT) neurons provides cardioprotective effects in heart disease models by targeting excitatory neurotransmission to brainstem cardiac vagal neurons.
View Article and Find Full Text PDFWorld J Pediatr Congenit Heart Surg
September 2025
Department of Cardiology, Boston Children's Hospital, Boston, MA, USA.
There is a paucity of data available regarding operative timing and approach for d-loop transposition of the great arteries (dTGA) with intact ventricular septum (IVS) in premature infants. We reviewed our surgical experience in a case series of five premature infants (<37 weeks gestational age) with dTGA/IVS and birthweights <2.0 kg.
View Article and Find Full Text PDFArch Gynecol Obstet
September 2025
The First Affiliated Hospital of Soochow University, No. 899 Pinghai Street, Suzhou, Jiangsu, China.
Objective: The study utilized non-invasive myocardial work indices to investigate myocardial injury in infants born to mothers with severe preeclampsia (SPE) and to explore the duration of this myocardial damage during the neonatal period.
Methods: This prospective study included 34 preterm infants born to mothers with SPE and 28 preterm infants born to mothers without severe pregnancy complications (termed "controls"). Echocardiography was performed in infants within 24 h of birth, then again at 48-72 h and 14-28 days, to obtain echocardiographic parameters.
PLoS One
September 2025
Children's Health Research Institute, Victoria Research Labs, London, Ontario, Canada.
Loss of actin cytoskeleton control can hinder integral developmental and physiological processes and can be the basis for a subset of developmental defects. SHROOM3 is an actin binding protein, best characterized as being essential for neural tube closure in vertebrates. Shroom3 expression has also been identified in the developing heart, with some associated congenital heart defects.
View Article and Find Full Text PDFAim: Hydrocephalus is a condition characterized by the excessive accumulation of cerebrospinal fluid in the brain's ventricular system, leading to ventricular enlargement and increased intracranial pressure. This study aimed to evaluate whether transfontanel ultrasonography could serve as a practical and less complex alternative to brain magnetic resonance imaging in infants with hydrocephalus.
Material And Methods: In this prospective study, 54 infants diagnosed with hydrocephalus underwent both transfontanel ultrasonography and brain magnetic resonance imaging.