Citations

Abstract Background Radiation-induced heart disease (RIHD) may develop months to years following radiation therapy for cancers near the heart such as lung or breast cancer. Several mouse models of RIHD exist to study the pathogenesis of disease, but to our knowledge no studies have examined whether sex differences exist in RIHD in mice. Methods Female and male BALB/cJ mice received one whole heart dose of 22 Gray (Gy) radiation via a C5 collimator vs. sham controls that received 0 Gy, anesthesia and were placed in the X-ray machine for the same length of time. Mechanisms of cardiotoxicity were examined at 24 h (innate cardiotoxicity), day 10 (acute cardiotoxicity) and day 35 (chronic cardiotoxicity) post irradiation. Results Females and males developed dsDNA breaks from radiation at day 10 but females had more damage than males ( p < 0.001). Vessel area and cardiac hypertrophy were increased by radiation at day 10 and 35 but were higher in males than females at day 35 ( p < 0.001, p = 0.001, respectively). Bulk RNA sequencing of the heart at day 10 revealed that females and males developed similar gene pathway responses to radiation by upregulating cellular repair pathways and downregulated mitochondrial function. However, females upregulated the master regulator of mitochondrial function, Pgc1α ( p = 0.0001), suggesting improved mitochondrial repair in females. By day 35, males developed heart failure with reduced ejection fraction (HFrEF), inflammatory dilated cardiomyopathy (iDCM) and fibrosis while females developed heart failure with preserved ejection fraction (HFpEF) without inflammation or fibrosis. Conclusions We observed sex differences in nearly every cardiac parameter that we examined following radiation exposure. BALB/c males exposed to 22 Gy radiation developed HFrEF and iDCM by day 35 while females developed HFpEF. Further research is needed to better understand mechanisms driving sex differences in RIHD using translational animal models.

Abstract Recent single-cell transcriptomic studies of follicular lymphoma (FL) have revealed heterogeneity among malignant B (MB) cells and selected components of the tumor microenvironment (TME), but have been constrained by relatively small sample sizes and a lack of spatial context. We performed comprehensive cellular profiling and spatial dissection of over five million cells by integrating single-nucleus RNA sequencing (snRNA-seq) from 182 samples (FL, n = 167; control, n = 15) with single-cell spatial transcriptomics (ST) from 386 samples (FL, n = 365; control, n = 21). After stringent quality control, 1,289,073 and 3,968,427 cells from snRNA-seq and ST data, respectively, were analyzed. Unsupervised clustering of snRNA-seq data identified 58 TME cell subtypes. To extend this classification to the ST dataset, we integrated snRNA-seq and ST data by co-embedding them into a shared principal component space, enabling robust batch correction and cell-type label transfer across modalities. Using this supervised annotation framework, ST data recapitulated 54 TME cell subtypes. MB, proliferating MB (MBprolif), and healthy B (HB) cells were classified using sample-level unsupervised clustering in ST. Macrophages exhibited previously uncharacterized heterogeneity in transcriptomic profiles and spatial distribution. We identified CXCL13-expressing macrophage subtypes with high intra- and peri-follicular abundance, termed follicular macrophages (FMs). Non-negative matrix factorization of intrafollicular cell fractions identified five TME archetypes: FM, follicular stroma, two follicular T, and HB archetypes. The FM archetype was enriched for intrafollicular macrophages, including FMs, and showed a significantly higher proportion of grade 3A/3B cases (53.4%) compared to other archetypes (≤16.5%). It was also associated with a higher frequency of high tumor burden requiring treatment initiation rather than a watch-and-wait (WW) approach. Among patients managed by WW, those with the FM archetype showed significantly shorter event-free survival (EFS) compared to those with non-FM archetypes, whereas this association was not observed among treated patients. The percentage of intrafollicular macrophages (IFMP) showed excellent predictive performance for the FM archetype (area under the curve: 0.90). IFMP calculated in a published multiplex spatial protein imaging dataset from an independent cohort of 242 FL patients validated the associations between high IFMP and both pathology grade 3A/3B and shorter EFS in WW patients. Consistently, spatial neighborhood and cell–cell communication analyses revealed co-localization of FMs and MBprolif cells, forming a distinct niche with activated signaling mediated by FM-derived CXCL13, APRIL, and BAFF. Our integrative multi-modal analysis defines previously unrecognized cellular heterogeneity and spatial architecture in FL and highlights macrophage-enriched follicular ecosystems associated with aggressive clinicopathological features, providing a framework for improved biological understanding and patient management. Citation Format: Yoshiaki Abe, Bijal Thakkar, Atish Kizhakeyil, Ashley Wilson, Andrew L. Feldman, Jared Henderson, Amy Ayers, Sara Borgschatz, R. Andrew Harkins, Priya Lakra, Daisuke Kaji, Jonathon B. Cohen, David Russler-Germain, Eric Mou, Francisco Vega, Jennifer Chapman, Giorgio Inghirami, Carla Casulo, Izidore S. Lossos, Jean L. Koff, Chijioke Nze, Peter Martin, Sergei Syrbu, Kiran Vij, David L. Jaye, James R. Cerhan, Christopher R. Flowers, Anne J. Novak, Richard Burack, Dai Chihara, Mamiko Sakata-Yanagimoto, Joshua Tobin, Xubin Li, Michael R. Green. Spatially resolved microenvironment profiling reveals distinct follicular lymphoma archetypes [abstract]. In: Proceedings of the Fifth AACR International Meeting on Advances in Malignant Lymphoma: From Discovery to Clinical Impact; 2026 Jun 24-27; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2026;7(3_Suppl):Abstract nr A049.

ABSTRACT Glioblastoma (GBM) is universally lethal despite decades of research to find effective treatments. This highlights the need to identify druggable targets essential for sustaining the malignant phenotype but dispensable for normal tissue. We propose that the enzyme α-tubulin acetyl transferase ( ATAT1 ) meets these criteria. ATAT1 acetylates α-tubulin at lysine 40, which increases microtubule stability and promotes microtubule-based transport. While ATAT1 knockout mice have only a very mild phenotype, ATAT1 suppression in GBM has multiple therapeutic effects by reducing tumor invasion, proliferation, and therapeutic resistance. These translate not only into improved survival with ATAT1 targeting by itself, but also into synergy when ATAT1 deletion is combined with FDA approved therapies. This study strongly supports our conclusion that ATAT1 is a promising therapeutic target in GBM.

Apply It! By reading this article, you will: • Understand how commonly used cardiorespiratory fitness prediction equations can misclassify fitness in both high-performance and clinical populations. • Learn how common prediction equations were developed and why the population of prediction equation studies matters when interpreting estimated cardiorespiratory fitness and percent-predicted values. • Recognize how to critically assess the suitability of a given cardiorespiratory fitness equation based on your client’s or patient’s characteristics.

PIK3CA-related overgrowth spectrum (PROS) encompasses rare disorders characterized by vascular malformations and predisposition to thrombotic complications. COVID-19 has been associated with diverse cutaneous manifestations through endothelial dysfunction and microvascular thrombosis. We present a 33-year-old female with PROS and extensive capillary malformations who developed multiple cutaneous ulcerations on her affected right leg exclusively during COVID-19 infection in 2020, with complete resolution following recovery. Preexisting endothelial abnormalities and thrombotic predisposition in PROS may create heightened vulnerability to COVID-19-induced vascular injury, explaining why cutaneous manifestations occurred exclusively in zones of capillary malformation. This susceptibility may be mediated by the Phosphoinositide 3-kinase/ Protein kinase B/ mechanistic target of Rapamycin (PI3K/AKT/mTOR) pathway, which regulates cell growth and vascular homeostasis, is constitutively activated in PROS, and is exploited by SARS-CoV-2 during infection. Clinicians managing patients with vascular malformations should be aware of this potential interaction.

Abstract Aims Heart failure (HF), a major global health challenge, affects millions worldwide and poses substantial healthcare and economic burdens. It is estimated that a large proportion of those with early systolic dysfunction remain asymptomatic at a stage when guideline-directed medical therapies have been shown to prevent disease progression. To develop an artificial intelligence (AI) model capable of predicting abnormal left ventricular ejection fraction (EF) directly from static, non-gated, non-contrast chest computed tomography (CT) scans as a form of opportunistic screening, Methods and results Using a multi-institutional dataset of 34 058 paired non- contrast CT images and echocardiogram reports from two academic centres, we trained our model of classification for predicting left-ventricle ejection fraction (LVEF) categories: abnormal EF (EF &lt; 50%) vs. normal on 25 948 studies. We validated the model on 8110 paired chest CT and echocardiogram results from a separate institution. The model achieved an area under the receiver operating characteristic (AUROC) curve of 0.786 on the hold-out test set and 0.762 on external validation to detect an abnormal EF (&lt;50%). Beyond strong predictive performance, the AI model surpassed expert radiologists in both accuracy and efficiency and provided interpretable visualizations highlighting imaging features linked to reduced LVEF. Conclusion In this study, we developed and validated an AI model capable of predicting abnormal LVEF directly from static, non-gated, non-contrast chest CT scans, a novel application for an imaging modality typically used for unrelated indications as a form of opportunistic screening. This technology holds significant promise for early detection of systolic HF, reducing the diagnostic gap, and improving outcomes in asymptomatic HF patients.