The Flt3-inhibitor quizartinib augments apoptosis and promotes maladaptive remodeling after myocardial infarction in mice.

BACKGROUND: Tyrosine kinase inhibitors (TKIs) targeting fms-like tyrosine kinase 3 (Flt3) such as quizartinib were specifically designed for acute myeloid leukemia treatment, but also multi-targeting TKIs applied to solid tumor patients inhibit Flt3. Flt3 is expressed in the heart and its activation is cytoprotective in myocardial infarction (MI) in mice. OBJECTIVES: We sought to test whether Flt3-targeting TKI treatment aggravates cardiac injury after MI. METHODS AND RESULTS: Compared to vehicle, quizartinib (10 mg/kg/day, gavage) did not alter cardiac dimensions or function in healthy mice after four weeks of therapy. Pretreated mice were randomly assigned to MI or sham surgery while receiving quizartinib or vehicle for one more week. Quizartinib did not aggravate the decline in ejection fraction, but significantly enhanced ventricular dilatation one week after infarction. In addition, apoptotic cell death was significantly increased in the myocardium of quizartinib-treated compared to vehicle-treated mice. In vitro, quizartinib dose-dependently decreased cell viability in neonatal rat ventricular myocytes and in H9c2 cells, and increased apoptosis as assessed in the latter. Together with H2O2, quizartinib potentiated the phosphorylation of the pro-apoptotic mitogen activated protein kinase p38 and augmented H2O2-induced cell death and apoptosis beyond additive degree. Pretreatment with a p38 inhibitor abolished apoptosis under quizartinib and H2O2. CONCLUSION: Quizartinib potentiates apoptosis and promotes maladaptive remodeling after MI in mice at least in part via a p38-dependent mechanism. These findings are consistent with the multi-hit hypothesis of cardiotoxicity and make cardiac monitoring in patients with ischemic heart disease under Flt3- or multi-targeting TKIs advisable.

Pulmonary Surfactant Proteins Are Inhibited by Immunoglobulin A Autoantibodies in Severe COVID-19.

Rationale: Coronavirus disease 2019 (COVID-19) can lead to acute respiratory distress syndrome with fatal outcomes. Evidence suggests that dysregulated immune responses, including autoimmunity, are key pathogenic factors. Objectives: To assess whether IgA autoantibodies target lung-specific proteins and contribute to disease severity. Methods: We collected 147 blood, 9 lung tissue, and 36 BAL fluid samples from three tertiary hospitals in Switzerland and one in Germany. Severe COVID-19 was defined by the need to administer oxygen. We investigated the presence of IgA autoantibodies and their effects on pulmonary surfactant in COVID-19 using the following methods: immunofluorescence on tissue samples, immunoprecipitations followed by mass spectrometry on BAL fluid samples, enzyme-linked immunosorbent assays on blood samples, and surface tension measurements with medical surfactant. Measurements and Main Results: IgA autoantibodies targeting pulmonary surfactant proteins B and C were elevated in patients with severe COVID-19 but not in patients with influenza or bacterial pneumonia. Notably, pulmonary surfactant failed to reduce surface tension after incubation with either plasma or purified IgA from patients with severe COVID-19. Conclusions: Our data suggest that patients with severe COVID-19 harbor IgA autoantibodies against pulmonary surfactant proteins B and C and that these autoantibodies block the function of lung surfactant, potentially contributing to alveolar collapse and poor oxygenation.

Impact of sex and gender on post-COVID-19 syndrome, Switzerland, 2020.

BackgroundWomen are overrepresented among individuals with post-acute sequelae of SARS-CoV-2 infection (PASC). Biological (sex) as well as sociocultural (gender) differences between women and men might account for this imbalance, yet their impact on PASC is unknown.AimWe assessed the impact of sex and gender on PASC in a Swiss population.MethodOur multicentre prospective cohort study included 2,856 (46% women, mean age 44.2 ± 16.8 years) outpatients and hospitalised patients with PCR-confirmed SARS-CoV-2 infection.ResultsAmong those who remained outpatients during their first infection, women reported persisting symptoms more often than men (40.5% vs 25.5% of men; p < 0.001). This sex difference was absent in hospitalised patients. In a crude analysis, both female biological sex (RR = 1.59; 95% CI: 1.41-1.79; p < 0.001) and a score summarising gendered sociocultural variables (RR = 1.05; 95% CI: 1.03-1.07; p < 0.001) were significantly associated with PASC. Following multivariable adjustment, biological female sex (RR = 0.96; 95% CI: 0.74-1.25; p = 0.763) was outperformed by feminine gender-related factors such as a higher stress level (RR = 1.04; 95% CI: 1.01-1.06; p = 0.003), lower education (RR = 1.16; 95% CI: 1.03-1.30; p = 0.011), being female and living alone (RR = 1.91; 95% CI: 1.29-2.83; p = 0.001) or being male and earning the highest income in the household (RR = 0.76; 95% CI: 0.60-0.97; p = 0.030).ConclusionSpecific sociocultural parameters that differ in prevalence between women and men, or imply a unique risk for women, are predictors of PASC and may explain, at least in part, the higher incidence of PASC in women. Once patients are hospitalised during acute infection, sex differences in PASC are no longer evident.

Defective Desmosomal Adhesion Causes Arrhythmogenic Cardiomyopathy by Involving an Integrin-αVß6/TGF-ß Signaling Cascade.

BACKGROUND: Arrhythmogenic cardiomyopathy (ACM) is characterized by progressive loss of cardiomyocytes with fibrofatty tissue replacement, systolic dysfunction, and life-threatening arrhythmias. A substantial proportion of ACM is caused by mutations in genes of the desmosomal cell-cell adhesion complex, but the underlying mechanisms are not well understood. In the current study, we investigated the relevance of defective desmosomal adhesion for ACM development and progression. METHODS: We mutated the binding site of DSG2 (desmoglein-2), a crucial desmosomal adhesion molecule in cardiomyocytes. This DSG2-W2A mutation abrogates the tryptophan swap, a central interaction mechanism of DSG2 on the basis of structural data. Impaired adhesive function of DSG2-W2A was confirmed by cell-cell dissociation assays and force spectroscopy measurements by atomic force microscopy. The DSG2-W2A knock-in mouse model was analyzed by echocardiography, ECG, and histologic and biomolecular techniques including RNA sequencing and transmission electron and superresolution microscopy. The results were compared with ACM patient samples, and their relevance was confirmed in vivo and in cardiac slice cultures by inhibitor studies applying the small molecule EMD527040 or an inhibitory integrin-αVß6 antibody. RESULTS: The DSG2-W2A mutation impaired binding on molecular level and compromised intercellular adhesive function. Mice bearing this mutation develop a severe cardiac phenotype recalling the characteristics of ACM, including cardiac fibrosis, impaired systolic function, and arrhythmia. A comparison of the transcriptome of mutant mice with ACM patient data suggested deregulated integrin-αVß6 and subsequent transforming growth factor-ß signaling as driver of cardiac fibrosis. Blocking integrin-αVß6 led to reduced expression of profibrotic markers and reduced fibrosis formation in mutant animals in vivo. CONCLUSIONS: We show that disruption of desmosomal adhesion is sufficient to induce a phenotype that fulfils the clinical criteria to establish the diagnosis of ACM, confirming the dysfunctional adhesion hypothesis. Deregulation of integrin-αVß6 and transforming growth factor-ß signaling was identified as a central step toward fibrosis. A pilot in vivo drug test revealed this pathway as a promising target to ameliorate fibrosis. This highlights the value of this model to discern mechanisms of cardiac fibrosis and to identify and test novel treatment options for ACM.

Serum Neurofilament Light Chain Levels in the Intensive Care Unit: Comparison between Severely Ill Patients with and without Coronavirus Disease 2019.

There is emerging evidence for multifarious neurological manifestations of coronavirus disease 2019 (COVID-19), but little is known regarding whether they reflect structural damage to the nervous system. Serum neurofilament light chain (sNfL) is a specific biomarker of neuronal injury. We measured sNfL concentrations of 29 critically ill COVID-19 patients, 10 critically ill non-COVID-19 patients, and 259 healthy controls. After adjusting for neurological comorbidities and age, sNfL concentrations were higher in patients with COVID-19 versus both comparator groups. Higher sNfL levels were associated with unfavorable short-term outcome, indicating that neuronal injury is common and pronounced in critically ill patients. ANN NEUROL 2021;89:610-616.

Regulatory RNAs in Heart Failure.

Cardiovascular disease is an enormous socioeconomic burden worldwide and remains a leading cause of mortality and disability despite significant efforts to improve treatments and personalize healthcare. Heart failure is the main manifestation of cardiovascular disease and has reached epidemic proportions. Heart failure follows a loss of cardiac homeostasis, which relies on a tight regulation of gene expression. This regulation is under the control of multiple types of RNA molecules, some encoding proteins (the so-called messenger RNAs) and others lacking protein-coding potential, named noncoding RNAs. In this review article, we aim to revisit the notion of regulatory RNA, which has been thus far mainly confined to noncoding RNA. Regulatory RNA, which we propose to abbreviate as regRNA, can include both protein-coding RNAs and noncoding RNAs, as long as they contribute, directly or indirectly, to the regulation of gene expression. We will address the regulation and functional role of messenger RNAs, microRNAs, long noncoding RNAs, and circular RNAs (ie, regRNAs) in heart failure. We will debate the utility of regRNAs to diagnose, prognosticate, and treat heart failure, and we will provide directions for future work.

Molecular imaging reveals rapid reduction of endothelial activation in early atherosclerosis with apocynin independent of antioxidative properties.

OBJECTIVE: Antioxidative drugs continue to be developed for the treatment of atherosclerosis. Apocynin is an nicotinamide adenine dinucleotide phosphate oxidase inhibitor with anti-inflammatory properties. We used contrast-enhanced ultrasound molecular imaging to assess whether short-term apocynin therapy in atherosclerosis reduces vascular oxidative stress and endothelial activation APPROACH AND RESULTS: Genetically modified mice with early atherosclerosis were studied at baseline and after 7 days of therapy with apocynin (4 mg/kg per day IP) or saline. Contrast-enhanced ultrasound molecular imaging of the aorta was performed with microbubbles targeted to vascular cell adhesion molecule 1 (VCAM-1; MB(V)), to platelet glycoprotein Ibα (MB(Pl)), and control microbubbles (MB(Ctr)). Aortic vascular cell adhesion molecule 1 was measured using Western blot. Aortic reactive oxygen species generation was measured using a lucigenin assay. Hydroethidine oxidation was used to assess aortic superoxide generation. Baseline signal for MBV (1.3 ± 0.3 AU) and MB(Pl )(1.5 ± 0.5 AU) was higher than for MBCtr (0.5 ± 0.2 AU; P<0.01). In saline-treated animals, signal did not significantly change for any microbubble agent, whereas short-term apocynin significantly (P<0.05) reduced vascular cell adhesion molecule 1 and platelet signal (MBV: 0.3 ± 0.1; MBPl: 0.4 ± 0.1; MBCtr: 0.3 ± 0.2 AU; P=0.6 between agents). Apocynin reduced aortic vascular cell adhesion molecule 1 expression by 50% (P<0.05). However, apocynin therapy did not reduce reactive oxygen species content, superoxide generation, or macrophage content. CONCLUSIONS: Short-term treatment with apocynin in atherosclerosis reduces endothelial cell adhesion molecule expression. This change in endothelial phenotype can be detected by molecular imaging before any measurable decrease in macrophage content and is not associated with a detectable change in oxidative burden.

Non-coding RNAs and their potential exploitation in cancer therapy-related cardiotoxicity.

Life expectancy in cancer patients has been extended in recent years, thanks to major breakthroughs in therapeutic developments. However, this also unmasked an increased incidence of cardiovascular diseases in cancer survivors, which is in part attributable to cancer therapy-related cardiovascular toxicity. Non-coding RNAs (ncRNAs) have received much appreciation due to their impact on gene expression. NcRNAs, which include microRNAs, long ncRNAs and circular RNAs, are non-protein-coding transcripts that are involved in the regulation of various biological processes, hence shaping cell identity and behaviour. They have also been implicated in disease development, including cardiovascular diseases, cancer and, more recently, cancer therapy-associated cardiotoxicity. This review outlines key features of cancer therapy-associated cardiotoxicity, what is known about the roles of ncRNAs in these processes and how ncRNAs could be exploited as therapeutic targets for cardioprotection.

TNF-α protects from exacerbated myocarditis and cardiac death by suppressing expansion of activated heart-reactive CD4+ T cells.

AIMS: Tumour necrosis factor α (TNF-α) represents a classical pro-inflammatory cytokine, and its increased levels positively correlate with the severity of many cardiovascular diseases. Surprisingly, some heart failure patients receiving high doses of anti-TNF-α antibodies showed serious health worsening. This work aimed to examine the role of TNF-α signalling on the development and progression of myocarditis and heart-specific autoimmunity. METHODS AND RESULTS: Mice with genetic deletion of TNF-α (Tnf+/- and Tnf-/-) and littermate controls (Tnf+/+) were used to study myocarditis in the inducible and the transgenic T cell receptor (TCRM) models. Tnf+/- and Tnf-/- mice immunized with α-myosin heavy chain peptide (αMyHC) showed reduced myocarditis incidence, but the susceptible animals developed extensive inflammation in the heart. In the TCRM model, defective TNF-α production was associated with increased mortality at a young age due to cardiomyopathy and cardiac fibrosis. We could confirm that TNF-α as well as the secretome of antigen-activated heart-reactive effector CD4+ T (Teff) cells effectively activated the adhesive properties of cardiac microvascular endothelial cells (cMVECs). Our data suggested that TNF-α produced by endothelial in addition to Teff cells promoted leucocyte adhesion to activated cMVECs. Analysis of CD4+ T lymphocytes from both models of myocarditis showed a strongly increased fraction of Teff cells in hearts, spleens, and in the blood of Tnf+/- and Tnf-/- mice. Indeed, antigen-activated Tnf-/- Teff cells showed prolonged long-term survival and TNF-α cytokine-induced cell death of heart-reactive Teff. CONCLUSION: TNF-α signalling promotes myocarditis development by activating cardiac endothelial cells. However, in the case of established disease, TNF-α protects from exacerbating cardiac inflammation by inducing activation-induced cell death of heart-reactive Teff. These data might explain the lack of success of standard anti-TNF-α therapy in heart failure patients and open perspectives for T cell-targeted approaches.

Cardiovascular management of cancer patients with chemotherapy-associated left ventricular systolic dysfunction in real-world clinical practice.

BACKGROUND: Chemotherapy-induced left ventricular systolic dysfunction (LVSD) may limit survival in cancer patients and therefore should be treated timely with appropriate heart failure medication. This study aimed to evaluate quality of cardiac care in cancer patients with documented chemotherapy-induced LVSD in real-world clinical practice. METHODS: Using an institutional echo database, we screened 1,520 cancer patients for first documentation of chemotherapy-associated LVSD, defined as left ventricular ejection fraction (LVEF) ≤45%. Hospital charts of all 63 patients meeting inclusion criteria were reviewed regarding patient characteristics and frequency of heart failure medication prescription. RESULTS: Patients were 61 (interquartile range [IQR], 50-70) years old, mostly symptomatic, and had an average LVEF of 34 ± 8%. Most patients received anthracyclines (73%) and/or alkylating agents (73%) as part of their chemotherapeutic regimen. Median time from cancer diagnosis to first documentation of LVSD was 2.2 (0.7-5.2) years. Fewer than two-thirds of patients received guideline-recommended heart failure medication, and only one-half of patients received cardiology consult. Cardiology consultation was associated with a significantly higher frequency of heart failure medication prescription (100% vs. 52% for angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (P < .0001); 94% vs. 41% for beta-blocker (P < .0001) and better survival (71% vs. 41%; P < .05). CONCLUSIONS: Chemotherapy-associated LVSD is insufficiently treated in cancer patients. Cardiology consultation improves rates of heart failure medication and therefore should be advocated in all patients with chemotherapy-induced LVSD.

Sex hormones in SARS-CoV-2 susceptibility: key players or confounders?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has a clear sex disparity in clinical outcomes. Hence, the interaction between sex hormones, virus entry receptors and immune responses has attracted major interest as a target for the prevention and treatment of SARS-CoV-2 infections. This Review summarizes the current understanding of the roles of androgens, oestrogens and progesterone in the regulation of virus entry receptors and disease progression of coronavirus disease 2019 (COVID-19) as well as their therapeutic value. Although many experimental and clinical studies have analysed potential mechanisms by which female sex hormones might provide protection against SARS-CoV-2 infectivity, there is currently no clear evidence for a sex-specific expression of virus entry receptors. In addition, reports describing an influence of oestrogen, progesterone and androgens on the course of COVID-19 vary widely. Current data also do not support the administration of oestradiol in COVID-19. The conflicting evidence and lack of consensus results from a paucity of mechanistic studies and clinical trials reporting sex-disaggregated data. Further, the influence of variables beyond biological factors (sex), such as sociocultural factors (gender), on COVID-19 manifestations has not been investigated. Future research will have to fill this knowledge gap as the influence of sex and gender on COVID-19 will be essential to understanding and managing the long-term consequences of this pandemic.

Fms-like tyrosine kinase 3 is a regulator of the cardiac side population in mice.

Fms-like tyrosine kinase 3 (Flt3) is a regulator of hematopoietic progenitor cells and a target of tyrosine kinase inhibitors. Flt3-targeting tyrosine kinase inhibitors can have cardiovascular side effects. Flt3 and its ligand (Flt3L) are expressed in the heart, but little is known about their physiological functions. Here, we show that cardiac side population progenitor cells (SP-CPCs) from mice produce and are responsive to Flt3L. Compared with wild-type, flt3L-/- mice have less SP-CPCs with less contribution of CD45-CD34+ cells and lower expression of genes related to epithelial-to-mesenchymal transition, cardiovascular development and stem cell differentiation. Upon culturing, flt3L-/- SP-CPCs show increased proliferation and less vasculogenic commitment, whereas Akt phosphorylation is lower. Notably, proliferation and differentiation can be partially restored towards wild-type levels in the presence of alternative receptor tyrosine kinase-activating growth factors signaling through Akt. The lower vasculogenic potential of flt3L-/- SP-CPCs reflects in decreased microvascularisation and lower systolic function of flt3L-/- hearts. Thus, Flt3 regulates phenotype and function of murine SP-CPCs and contributes to cellular and molecular properties that are relevant for their cardiovasculogenic potential.

Clinical utility of inflammatory biomarkers in COVID-19 in direct comparison to other respiratory infections-A prospective cohort study.

BACKGROUND: Inflammatory biomarkers are associated with severity of coronavirus disease 2019 (COVID-19). However, direct comparisons of their utility in COVID-19 versus other respiratory infections are largely missing. OBJECTIVE: We aimed to investigate the prognostic utility of various inflammatory biomarkers in COVID-19 compared to patients with other respiratory infections. MATERIALS AND METHODS: Patients presenting to the emergency department with symptoms suggestive of COVID-19 were prospectively enrolled. Levels of Interleukin-6 (IL-6), c-reactive protein (CRP), procalcitonin, ferritin, and leukocytes were compared between COVID-19, other viral respiratory infections, and bacterial pneumonia. Primary outcome was the need for hospitalisation, secondary outcome was the composite of intensive care unit (ICU) admission or death at 30 days. RESULTS: Among 514 patients with confirmed respiratory infections, 191 (37%) were diagnosed with COVID-19, 227 (44%) with another viral respiratory infection (viral controls), and 96 (19%) with bacterial pneumonia (bacterial controls). All inflammatory biomarkers differed significantly between diagnoses and were numerically higher in hospitalized patients, regardless of diagnoses. Discriminative accuracy for hospitalisation was highest for IL-6 and CRP in all three diagnoses (in COVID-19, area under the curve (AUC) for IL-6 0.899 [95%CI 0.850-0.948]; AUC for CRP 0.922 [95%CI 0.879-0.964]). Similarly, IL-6 and CRP ranged among the strongest predictors for ICU admission or death at 30 days in COVID-19 (AUC for IL-6 0.794 [95%CI 0.694-0.894]; AUC for CRP 0.807 [95%CI 0.721-0.893]) and both controls. Predictive values of inflammatory biomarkers were generally higher in COVID-19 than in controls. CONCLUSION: In patients with COVID-19 and other respiratory infections, inflammatory biomarkers harbour strong prognostic information, particularly IL-6 and CRP. Their routine use may support early management decisions.

Case report of elevation of high-sensitivity cardiac troponin T in the absence of cardiac involvement in immune checkpoint inhibitor-associated myositis.

Background: Immune checkpoint inhibitors (ICIs) have markedly improved outcome in various types of cancer. ICI-associated myocarditis is one of the most severe immune-related adverse events. In particular, high concentrations of cardiac troponin T (cTnT) are associated with a high risk of death and early detection and vigorous therapy with high-dose steroids may improve survival. However, chronic skeletal muscle disorders have been suggested as a non-cardiac source of elevated high-sensitivity cardiac troponin T (hs-cTnT) concentrations. Case summary: Here, we present the case of a 72-year-old patient with metastatic melanoma treated with nivolumab and ipilimumab, who developed symptomatic myositis [creatine kinase (CK) max. 3113 U/L]. Due to substantially elevated concentrations of hs-cTnT (max. 1128 ng/L, normal <14 ng/L, Elecsys), the patient was referred to the cardio-oncology unit for evaluation of concomitant myocarditis. The patient did not report any cardiac symptoms and there were no clinical signs of congestion or rhythm abnormalities. Concentrations of NT-proBNP were within the normal range. Echocardiography showed normal cardiac dimensions and normal systolic and diastolic function. Cardiac magnetic resonance imaging confirmed these findings and also showed no evidence of acute or post-inflammatory myocardial tissue changes. Absence of relevant cardiomyocyte injury was supported by determination of normal levels of cardiac troponin I concentrations and made endomyocardial biopsy in this severely ill patient unnecessary. Discussion: Our observation documents ICI-induced myositis as an alternative non-cardiac cause of hs-cTnT elevation. A global cardiologic approach employing clinical and cardiac magnetic resonance imaging data as well as NT-proBNP and cardiac troponin I helps to identify false positive hs-TnT elevation under ICI therapy.

Sex disparities in patients with suspected COVID-19 presenting at an emergency department in Switzerland.

AIMS OF THE STUDY: In the global COVID-19 pandemic, female sex is associated with comparable infection rates but better outcome. However, most studies lacked appropriate controls. We investigated whether these sex disparity findings are specific to patients with COVID-19 or generalizable to patients presenting to the emergency room (ER) with similar symptoms but no COVID-19. METHODS: In this prospective cohort study, consecutive patients presenting with symptoms suggestive of COVID-19 were recruited at the ER of the University Hospital Basel, Switzerland from March to June 2020. Patients were categorized as SARS-CoV-2 positive (cases) or negative (controls) based on nasopharyngeal PCR swab tests. The final clinical diagnosis was determined for all patients. The primary outcome was a composite of intensive care admission, rehospitalization for respiratory distress and all-cause death within 30 days. We used Kaplan-Meier curves and Cox proportional hazards models to explore associations between sex and outcomes. RESULTS: Among 1,081 consecutive ER patients, 191 (18%) tested positive for SARS-CoV-2, with an even sex distribution (17.9% female vs. 17.5% male, p = 0.855). In COVID-19 patients, female sex was associated with lower risk of hospitalization (51% vs. 66%, p = 0.034), lower necessity of haemodynamic support (8% vs. 20%, p = 0.029), lower rates of intubation (10% vs. 21%, p = 0.037) and the primary outcome (18% vs. 31%, p = 0.045; age-adjusted HR 0.536, 95%CI 0.290-0.989, p = 0.046) compared with male sex. Sex disparities were most prominent in patients ≥55 years (HR for composite primary outcome in women 0.415, 95%CI 0.201-0.855, p = 0.017). In contrast to the COVID-19 patients, no sex-specific differences in outcomes were observed in the unselected overall control group (age-adjusted HR 0.844, 95%CI 0.560-1.273, p = 0.419) or in a subgroup of controls with upper respiratory tract infections or pneumonia (age-adjusted HR 0.840, 95%CI 0.418-1.688, p = 0.624). CONCLUSION: In this unselected, consecutive cohort study at a tertiary hospital in Switzerland, female sex is associated with better outcome in patients presenting to the ER with COVID-19. These sex disparities seem to be at least partly specific to COVID-19, as they were not observed in comparable controls.