Aims Cardiac immune-related adverse events (irAEs) from immune checkpoint inhibition (ICI) targeting programmed death 1 (PD1) are of growing concern. Once cardiac irAEs become clinically manifest, fatality rates are high. Cardio-oncology aims to prevent detrimental effects before manifestation of severe complications by targeting early pathological changes. We therefore aimed to investigate early consequences of PD1 inhibition for cardiac integrity to prevent the development of overt cardiac disease. Methods and results We investigated cardiac-specific consequences from anti-PD1 therapy in a combined biochemical and in vivo phenotyping approach. Mouse hearts showed broad expression of the ligand PDL1 on cardiac endothelial cells as a main mediator of immune-crosstalk. Using a novel melanoma mouse model, we assessed that anti-PD1 therapy promoted myocardial infiltration with CD4+ and CD8+ T cells, the latter being markedly activated. Left ventricular (LV) function was impaired during pharmacological stress, as shown by pressure–volume catheterization. This was associated with a dysregulated myocardial metabolism, including the proteome and the lipidome. Analogous to the experimental approach, in patients with metastatic melanoma (n = 7) receiving anti-PD1 therapy, LV function in response to stress was impaired under therapy. Finally, we identified that blockade of tumour necrosis factor alpha (TNFα) preserved LV function without attenuating the anti-cancer efficacy of anti-PD1 therapy. Conclusions Anti-PD1 therapy induces a disruption of cardiac immune homeostasis leading to early impairment of myocardial functional integrity, with potential prognostic effects on the growing number of treated patients. Blockade of TNFα may serve as an approach to prevent the manifestation of ICI-related cardiotoxicity.

Cardioprotection by salvage of the infarct-affected myocardium is an unmet yet highly desired therapeutic goal. To develop new dedicated therapies, experimental myocardial ischemia/reperfusion (I/R) injury would require methods to simultaneously characterize extent and localization of the damage and the ensuing inflammatory responses in whole hearts over time. Here we present a three-dimensional (3D), simultaneous quantitative investigation of key I/R injury-components by combining bleaching-augmented solvent-based non-toxic clearing (BALANCE) using ethyl cinnamate (ECi) with light sheet fluorescence microscopy. This allows structural analyses of fluorescence-labeled I/R hearts with exceptional detail. We discover and 3D-quantify distinguishable acute and late vascular I/R damage zones. These contain highly localized and spatially structured neutrophil infiltrates that are modulated upon cardiac healing. Our model demonstrates that these characteristic I/R injury patterns can detect the extent of damage even days after the ischemic index event hence allowing the investigation of long-term recovery and remodeling processes.

Aims Childhood cancer therapy is associated with a significant risk of therapy-related cardiotoxicity. This meta-analysis aims to evaluate cardiac biomarkers for the detection of cancer therapy-related left ventricular (LV) dysfunction in childhood cancer patients. Methods and results PubMed, Cochrane Library, Wiley Library, and Web of Science were screened for studies investigating brain natriuretic peptide (BNP)/N-terminal proBNP (NT-proBNP) or cardiac troponin in childhood cancer patients. The odds ratios (OR) for elevation of cardiac biomarkers and association with LV dysfunction were calculated using a random-effects model. Data from 27 studies with 1651 subjects were included. BNP/NT-proBNP levels were higher post-treatment compared with controls or pre-treatment values [standardized mean difference = 1.0; 95% confidence interval (CI) = 0.6-1.4; n = 320; P < 0.001]. LV dysfunction was present in 11.76% of included patients, and risk for LV dysfunction was increased in patients with elevated BNP/NT-proBNP (OR = 7.1; 95% CI = 2.0-25.5; n = 350; P = 0.003). The sensitivity of BNP/NT-proBNP for the detection of LV dysfunction was 33.3%, and the specificity was 91.5%. Sensitivity increased when selecting for studies that assessed patients < 5 years after anthracycline exposure and for studies including high cumulative anthracycline doses. Anthracycline chemotherapy was associated with an increased frequency of elevated troponin (OR = 3.7; 95% CI = 2.1-6.5; n = 348; P < 0.001). The available evidence on the association between elevated troponin and LV dysfunction was insufficient for an adequate analysis. In five included studies, the frequency of LV dysfunction was not increased in patients with elevated troponin (OR = 2.5; 95% CI = 0.5-13.2; n = 179; P = 0.53). Conclusions BNP/NT-proBNP is associated with cardiotoxicity in paediatric cancer patients receiving anthracycline therapy, but owing to low sensitivity, BNP/NT-proBNP has to be evaluated in the context of further parameters including clinical assessment and echocardiography. Future studies are needed to determine whether troponin serves as a marker for cardiotoxicity in children. Standardized recommendations for the application of cardiac biomarkers in children undergoing cardiotoxic cancer therapy may benefit management and clinical outcome.

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Blood vasculature represents a complex network of vessels with varying lengths and diameters that are precisely organized in space to allow proper tissue function. Light-sheet fluorescence microscopy (LSFM) is very useful to generate tomograms of tissue vasculature with high spatial accuracy. Yet, quantitative LSFM analysis is still cumbersome and available methods are restricted to single organs and advanced computing hardware. Here, we introduce VesselExpress, an automated software that reliably analyzes six characteristic vascular network parameters including vessel diameter in LSFM data on average computing hardware. VesselExpress is ~100 times faster than other existing vessel analysis tools, requires no user interaction, integrates batch processing, and parallelization. Employing an innovative dual Frangi filter approach we show that obesity induces a large-scale modulation of brain vasculature in mice and that seven other major organs differ strongly in their 3D vascular makeup. Hence, VesselExpress transforms LSFM from an observational to an analytical working tool.