Daily Cardiology Research Analysis

BACKGROUND AND AIMS: Calcific aortic valve disease (CAVD) culminates in severe aortic stenosis, currently lacking pharmacological treatment. Intra-leaflet haemorrhage-induced iron overload promotes valvular ferroptosis. This study identifies a druggable ferroptosis pathway and validates its translational relevance across large-scale population cohorts. METHODS: Bulk- and single-cell transcriptomics, whole-mount histology, immunohistochemistry, and primary human valvular interstitial cell (VIC) models of 212 aortic valves from surgical patients were integrated for mechanistic insights. In vivo, valvular ferroptosis and thickness were assessed in a doxorubicin-induced ferroptosis mice model, and a wire injury model with ferroptosis inhibition was utilized to evaluate remodelling and haemodynamic obstruction. A total of 4874 participants of the Swedish CArdioPulmonary bioImage Study (SCAPIS) underwent cardiac computed tomography for aortic valve calcification determination and 273 550 individuals from the UK Biobank were followed for aortic stenosis incidence. RESULTS: Intra-leaflet haemorrhage was prevalent in calcified aortic valves and correlated positively with calcification and circulating ferroptosis biomarker. Bulk transcriptomics and single-cell RNA sequencing identified lipid peroxidation as the dominating valvular ferroptosis pathway centred on arachidonate 5-lipoxygenase (ALOX5). Inducing ferroptosis in VIC triggered lipid peroxidation and calcification while reducing viability, which were reversed by targeting the ALOX5-ACSL4 axis. In vivo, doxorubicin-induced valvular ferroptosis exacerbated valvular thickening in apoE-/- mice through ALOX5-ACSL4 upregulation. ALOX5 inhibition reduced valve thickness and haemodynamically improved valve function in the wire injury model. Arachidonic acid levels independently predicted aortic valve calcification and incident aortic stenosis in SCAPIS and UK Biobank, respectively, and positively correlated with circulating ferroptotic marker. CONCLUSIONS: These findings establish the ALOX5-ACSL4 axis as a critical mediator of ferroptosis in CAVD and promising repurposing target for clinical intervention.

BACKGROUND: Cardiac computed tomography (CT) acquired during the acute stroke imaging protocol is an emerging modality to detect cardiac thrombi. We determined its yield in patients with acute ischemic stroke. METHODS: We performed a 1-stage individual patient data meta-analysis of 4 prospective observational cohorts (AIS of HEARTS [Acute Ischemic Stroke of Heart-Related Embolic Sources Detected on Acute Cardiac CT Scans]), including patients with acute ischemic stroke who underwent ECG-gated or non-ECG-gated cardiac CT between May 2018 and June 2024. We excluded patients with transient ischemic attack or stroke mimics. The primary outcome was the proportion of patients with a thrombus on cardiac CT. Secondary outcomes were additional scan time, radiation dose, comparison with echocardiography, and 90-day outcomes. We performed logistic regression analyses to compare 90-day outcomes between patients with and without thrombus, adjusting for age, sex, history of atrial fibrillation, ischemic heart disease, chronic heart failure, stroke or transient ischemic attack, anticoagulant use, prestroke modified Rankin Scale score, National Institutes of Health Stroke Scale score, large vessel occlusions, and intravenous thrombolysis, as appropriate for each outcome. RESULTS: We included 3919 patients (median age, 74 [interquartile range (IQR), 63-82], 58% male, median National Institutes of Health Stroke Scale score 6 [IQR, 3-12]). Cardiac CT detected a thrombus in 243 (6.2%) patients. Among 1323 patients that underwent both cardiac CT and transthoracic echocardiography, cardiac CT had a higher yield than transthoracic echocardiography (odds ratio, 7.4 [95% CI, 4.0-15.1]; CONCLUSIONS: Implementing cardiac CT into the acute stroke imaging protocol is feasible, detects thrombi in ≈6% of patients, and has a higher yield than transthoracic echocardiography. Cardiac thrombi were associated with higher mortality, but not higher stroke recurrence. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT07165093.

The sodium-dependent multivitamin transporter, encoded by SLC5A6, mediates cellular uptake of biotin and pantothenic acid, essential cofactors for energy metabolism. We identified two families with SLC5A6 mutations presenting with early-onset dilated cardiomyopathy (DCM). To investigate the link between vitamin deficiency and cardiomyopathy, we generated a cardiac-specific SLC5A6 knockout (Slc5a6cKO) mouse model and evaluated the impact of vitamin supplementation. Slc5a6cKO mice developed progressive cardiac dysfunction, culminating in cardiac pathology and premature death at 26 weeks; earlier stages exhibited cardiomyocyte hypertrophy, fibrosis, impaired Coenzyme A synthesis, and metabolic imbalance, indicating progression toward cardiomyopathy. Cardiac magnetic resonance imaging and ECG confirmed progressive functional decline. Proteomic analysis revealed early mitochondrial metabolic disruption and extracellular matrix protein upregulation at 8 weeks, preceding overt cardiac dysfunction. Strikingly, vitamin supplementation from preconception onwards prevented the cardiac phenotype, preserving cardiac structure, function, morphology and survival. This paralleled the clinical outcome in one patient who received early vitamin treatment, compared to another who required a heart transplant without vitamin treatment. This study establishes a direct link between SLC5A6-mediated vitamin transport, mitochondrial function, and cardiac health. It highlights how vitamin deficiency contributes to cardiomyopathy pathogenesis and supports early vitamin supplementation as a potential therapeutic strategy for metabolic cardiomyopathies.