Increased [18F]FDG uptake in the infarcted myocardial area displayed by combined PET/CMR correlates with snRNA-seq-detected inflammatory cell invasion.

Combined [18F]FDG PET-cardiac MRI imaging (PET/CMR) is a useful tool to assess myocardial viability and cardiac function in patients with acute myocardial infarction (AMI). Here, we evaluated the prognostic value of PET/CMR in a porcine closed-chest reperfused AMI (rAMI) model. Late gadolinium enhancement by PET/CMR imaging displayed tracer uptake defect at the infarction site by 3 days after the rAMI in the majority of the animals (group Match, n = 28). Increased [18F]FDG uptake at the infarcted area (metabolism/contractility mismatch) with reduced tracer uptake in the remote viable myocardium (group Mismatch, n = 12) 3 days after rAMI was observed in the animals with larger infarct size and worse left ventricular ejection fraction (LVEF) (34 ± 8.7 vs 42.0 ± 5.2%), with lower LVEF also at the 1-month follow-up (35.8 ± 9.5 vs 43.0 ± 6.3%). Transcriptome analyses by bulk and single-nuclei RNA sequencing of the infarcted myocardium and border zones (n = 3 of each group, and 3 sham-operated controls) revealed a strong inflammatory response with infiltration of monocytes and macrophages in the infarcted and border areas in Mismatch animals. Our data indicate a high prognostic relevance of combined PET/MRI in the subacute phase of rAMI for subsequent impairment of heart function and underline the adverse effects of an excessive activation of the innate immune system in the initial phase after rAMI.

A CircRNA-miRNA-mRNA Network for Exploring Doxorubicin- and Myocet-Induced Cardiotoxicity in a Translational Porcine Model.

Despite the widespread use of doxorubicin (DOX) as a chemotherapeutic agent, its severe cumulative cardiotoxicity represents a significant limitation. While the liposomal encapsulation of doxorubicin (Myocet, MYO) reduces cardiotoxicity, it is crucial to understand the molecular background of doxorubicin-induced cardiotoxicity. Here, we examined circular RNA expression in a translational model of pigs treated with either DOX or MYO and its potential impact on the global gene expression pattern in the myocardium. This study furthers our knowledge about the regulatory network of circRNA/miRNA/mRNA and its interaction with chemotherapeutics. Domestic pigs were treated with three cycles of anthracycline drugs (DOX, n = 5; MYO, n = 5) to induce cardiotoxicity. Untreated animals served as controls (control, n = 3). We applied a bulk mRNA-seq approach and the CIRIquant algorithm to identify circRNAs. The most differentially regulated circRNAs were validated under cell culture conditions, following forecasting of the circRNA-miRNA-mRNA network. We identified eight novel significantly regulated circRNAs from exonic and mitochondrial regions in the porcine myocardium. The forecasted circRNA-miRNA-mRNA network suggested candidate circRNAs that sponge miR-17, miR-15b, miR-130b, the let-7 family, and miR125, together with their mRNA targets. The identified circRNA-miRNA-mRNA network provides an updated, coherent view of the mechanisms involved in anthracycline-induced cardiotoxicity.

Effect of monovalent COVID-19 vaccines on viral interference between SARS-CoV-2 and several DNA viruses in patients with long-COVID syndrome.

Epstein-Barr virus (EBV) reactivation may be involved in long-COVID symptoms, but reactivation of other viruses as a factor has received less attention. Here we evaluated the reactivation of parvovirus-B19 and several members of the Herpesviridae family (DNA viruses) in patients with long-COVID syndrome. We hypothesized that monovalent COVID-19 vaccines inhibit viral interference between SARS-CoV-2 and several DNA viruses in patients with long-COVID syndrome, thereby reducing clinical symptoms. Clinical and laboratory data for 252 consecutive patients with PCR-verified past SARS-CoV-2 infection and long-COVID syndrome (155 vaccinated and 97 non-vaccinated) were recorded during April 2021-May 2022 (median 243 days post-COVID-19 infection). DNA virus-related IgG and IgM titers were compared between vaccinated and non-vaccinated long-COVID patients and with age- and sex-matched non-infected, unvaccinated (pan-negative for spike-antibody) controls. Vaccination with monovalent COVID-19 vaccines was associated with significantly less frequent fatigue and multiorgan symptoms (p < 0.001), significantly less cumulative DNA virus-related IgM positivity, significantly lower levels of plasma IgG subfractions 2 and 4, and significantly lower quantitative cytomegalovirus IgG and IgM and EBV IgM titers. These results indicate that anti-SARS-CoV-2 vaccination may interrupt viral cross-talk in patients with long-COVID syndrome (ClinicalTrials.gov Identifier: NCT05398952).

Novel Identified Circular Transcript of RCAN2, circ-RCAN2, Shows Deviated Expression Pattern in Pig Reperfused Infarcted Myocardium and Hypoxic Porcine Cardiac Progenitor Cells In Vitro.

Circular RNAs (circRNAs) are crucial in gene regulatory networks and disease development, yet circRNA expression in myocardial infarction (MI) is poorly understood. Here, we harvested myocardium samples from domestic pigs 3 days after closed-chest reperfused MI or sham surgery. Cardiac circRNAs were identified by RNA-sequencing of rRNA-depleted RNA from infarcted and healthy myocardium tissue samples. Bioinformatics analysis was performed using the CIRIfull and KNIFE algorithms, and circRNAs identified with both algorithms were subjected to differential expression (DE) analysis and validation by qPCR. Circ-RCAN2 and circ-C12orf29 expressions were significantly downregulated in infarcted tissue compared to healthy pig heart. Sanger sequencing was performed to identify the backsplice junctions of circular transcripts. Finally, we compared the expressions of circ-C12orf29 and circ-RCAN2 between porcine cardiac progenitor cells (pCPCs) that were incubated in a hypoxia chamber for different time periods versus normoxic pCPCs. Circ-C12orf29 did not show significant DE in vitro, whereas circ-RCAN2 exhibited significant ischemia-time-dependent upregulation in hypoxic pCPCs. Overall, our results revealed novel cardiac circRNAs with DE patterns in pCPCs, and in infarcted and healthy myocardium. Circ-RCAN2 exhibited differential regulation by myocardial infarction in vivo and by hypoxia in vitro. These results will improve our understanding of circRNA regulation during acute MI.

Circular RNAs in Cardiac Regeneration: Cardiac Cell Proliferation, Differentiation, Survival, and Reprogramming.

Circular RNAs (circRNAs) are classified as long non-coding RNAs (lncRNAs) that are characterized by a covalent closed-loop structure. This closed-loop shape is the result of a backsplicing event in which the 3' and 5' splice sites are ligated. Through the lack of 3' poly(A) tails and 5' cap structures, circRNAs are more stable than linear RNAs because these adjustments make the circular loop less susceptible to exonucleases. The majority of identified circRNAs possess cell- and tissue-specific expression patterns. In addition, high-throughput RNA-sequencing combined with novel bioinformatics algorithms revealed that circRNA sequences are often conserved across different species suggesting a positive evolutionary pressure. Implicated as regulators of protein turnover, micro RNA (miRNA) sponges, or broad effectors in cell differentiation, proliferation, and senescence, research of circRNA has increased in recent years. Particularly in cardiovascular research, circRNA-related discoveries have opened the door for the development of potential diagnostic and therapeutic tools. Increasing evidence links deviating circRNA expression patterns to various cardiovascular diseases including ischemic heart failure. In this mini-review, we summarize the current state of knowledge on circRNAs in cardiac regeneration with a focus on cardiac cell proliferation, differentiation, cardiomyocyte survival, and cardiac reprogramming.

Association between Circular RNA CDR1as and Post-Infarction Cardiac Function in Pig Ischemic Heart Failure: Influence of the Anti-Fibrotic Natural Compounds Bufalin and Lycorine.

Anti-fibrotic therapies are of increasing interest to combat cardiac remodeling and heart failure progression. Recently, anti-fibrotic circular RNAs (circRNAs) have been identified in human and rodent cardiac tissue. In vivo (rodent) experiments proved cardiac anti-fibrotic effects of the natural compounds bufalin and lycorine by downregulating miRNA-671-5p, associated with a theoretic increase in the tissue level of circRNA CDR1as. Accordingly, we hypothesized that both anti-fibrotic drugs may inhibit focal myocardial fibrosis of the remodeled left ventricle (LV) also in a translational large animal model of heart failure (HF). Domestic pigs were repeatedly treated with subcutaneous injections of either bufalin, lycorine, or saline, (n = 5/group) between days 7-21 post acute myocardial infarction (AMI). At the 2-month follow-up, both bufalin and lycorine led to significantly reduced cardiac fibrosis. Bufalin treatment additionally led to smaller end-diastolic volumes, higher LV ejection fraction (EF), and increased expression of CDR1as of the AMI region. Elevated tissue levels of the circRNA CDR1as in the AMI region of the pig heart correlated significantly with LV and right ventricular EF, LV stroke volume, and negatively with infarct size. In conclusion, we successfully identified the circRNA CDR1as in pig hearts and show a significant association with improved LV and RV function by anti-fibrotic therapies in a translational animal model of HF.

Early Elevation of Systemic Plasma Clusterin after Reperfused Acute Myocardial Infarction in a Preclinical Porcine Model of Ischemic Heart Disease.

Clusterin exerts anti-inflammatory, cytoprotective and anti-apoptotic effects. Both an increase and decrease of clusterin in acute myocardial infarction (AMI) has been reported. We aimed to clarify the role of clusterin as a systemic biomarker in AMI. AMI was induced by percutaneous left anterior artery (LAD) occlusion for 90 min followed by reperfusion in 24 pigs. Contrast ventriculography was performed after reperfusion to assess left ventricular ejection fraction (LVEF), left ventricular end diastolic volume (LVEDV) and left ventricular end systolic volume (LVESV) and additional cMRI + late enhancement to measure infarct size and LV functions at day 3 and week 6 post-MI. Blood samples were collected at prespecified timepoints. Plasma clusterin and other biomarkers (cTnT, NT-proBNP, neprilysin, NGAL, ET-1, osteopontin, miR21, miR29) were measured by ELISA and qPCR. Gene expression profiles of infarcted and remote region 3 h (n = 5) and 3 days (n = 5) after AMI onset were analysed by RNA-sequencing. AMI led to an increase in LVEDV and LVESV during 6-week, with concomitant elevation of NT-proBNP 3-weeks after AMI. Plasma clusterin levels were increased immediately after AMI and returned to normal levels until 3-weeks. Plasma NGAL, ET-1 and miR29 was significantly elevated at 3 weeks follow-up, miR21 increased after reperfusion and at 3 weeks post-AMI, while circulating neprilysin levels did not change. Elevated plasma clusterin levels 120 min after AMI onset suggest that clusterin might be an additional early biomarker of myocardial ischemia.

The Long-Term Effectiveness and Cost Effectiveness of Organized versus Opportunistic Screening for Breast Cancer in Austria.

BACKGROUND: In 2014, Austrian health authorities implemented an organized breast cancer screening program. Until then, there has been a long-standing tradition of opportunistic screening. OBJECTIVES: To evaluate the cost-effectiveness of organized screening compared with opportunistic screening, as well as to identify factors influencing the clinical and economic outcomes. METHODS: We developed and validated an individual-level state-transition model and assessed the health outcomes and costs of organized and opportunistic screening for 40-year-old asymptomatic women. The base-case analysis compared a scenario involving organized biennial screening with a scenario reflecting opportunistic screening practice for an average-risk woman aged 45 to 69 years. We applied an annual discount rate of 3% and estimated the incremental cost-effectiveness ratio in terms of the cost (2012 euros) per life-year gained (LYG) from a health care perspective. Deterministic and probabilistic sensitivity analyses were performed to assess uncertainty. RESULTS: Compared with opportunistic screening, an organized program yielded on average additional 0.0118 undiscounted life-years (i.e., 4.3 days) and cost savings of €41 per woman. In the base-case analysis, the incremental cost-effectiveness ratio of organized screening was approximately €20,000 per LYG compared with no screening. Assuming a willingness-to-pay threshold of €50,000 per LYG, there was a 70% probability that organized screening would be considered cost-effective. The attendance rate, but not the test accuracy of mammography, was an influential factor for the cost-effectiveness. CONCLUSIONS: The decision to adopt organized screening is likely an efficient use of limited health care resources in Austria.