Autoimmune myocarditis is not associated with left ventricular systolic dysfunction.

BACKGROUND: Experimental autoimmune myocarditis (EAM) is a common animal model for the investigation of the pathophysiology of myocarditis. Because of diverging findings from previous studies, we performed serial echocardiographic examinations throughout the course of the disease and investigated the dimensions of the murine heart and left ventricular (LV) systolic function. MATERIALS AND METHODS: Experimental autoimmune myocarditis was induced in male Balb/c mice by subcutaneous injection of a fragment of the α-myosin heavy chain (MyHC-α 614-629: Ac-SLKLMATLFSTYASAD). Transthoracic echocardiography was performed on days 0, 7 and 21 in healthy animals and mice with EAM. RESULTS: Experimental autoimmune myocarditis was associated with a reduction in LV systolic function and an increase in LV internal diameter in diastole (LVIDd) and systole (LVIDs) 7 days postimmunization. After 21 days, EAM led to a significant increase in LV-thickness (1.3-fold increase in LV anterior wall diameter in diastole [LVAWDd]), but there was no difference in LV systolic function between immunized animals and healthy controls. LV-thickness correlated well with the severity of myocarditis in the histopathological examination (LVAWDd: rs = 0.603, P = 0.003, LV anterior wall diameter in systole (LVAWDs): rs = 0.718, P < 0.0001). CONCLUSION: Our results indicate that EAM leads to an initial dilatation of the LV that is followed by ventricular "hypertrophy." On day 21, there was no significant difference in LV systolic function between immunized animals and controls. Furthermore, the ageing of the animals had a major impact on the echocardiographic parameters; therefore, the use of healthy age-matched controls seems warranted when echocardiography is performed in rodents.

Disease-specific characteristics of vascular cell adhesion molecule-1 levels in patients with peripheral artery disease.

Peripheral arterial disease (PAD) is one of the most common manifestations of systemic atherosclerosis. The prevalence of unrecognized PAD is high, leading to a lack of opportunity to detect subjects at a high risk for cardiovascular events. Inflammatory processes play an important role in the disease initiation as well as in the disease progression. Vascular cell adhesion molecule 1 (VCAM-1), a biomarker of endothelial dysfunction, appears to be an important mediator in inflammatory processes. Therefore, we hypothesized that in patients with PAD, circulating VCAM-1 might be elevated due to its function in mediating adhesion of immune cells to the vascular endothelium in the process of endothelial dysfunction and inflammation, and, therefore, applicable as a diagnostic biomarker. A total of 126 non-consecutive patients were enrolled in this study, of whom 51 patients had typical clinical manifestations of PAD and as controls 75 patients with no history of PAD or cardiovascular disease. All serum samples were obtained either during hospitalization or during out-patient visits and analyzed for VCAM-1 by the ELISA. Compared with controls, median levels of VCAM-1 were significantly elevated in patients suffering from PAD (953 vs. 1352 pg/ml; p < 0.001). Furthermore, VCAM-1 appeared to be highly discriminative for the detection of PAD (AUC = 0.76; CI 0.67-0.83). We could not observe dynamics related to increasing disease stages according to Rutherford classes in patients with apparent PAD. VCAM-1 was shown to be a potential discriminator and biomarker for the severity of systemic atherosclerosis. In a logistic regression analysis, VCAM-1 was robustly associated with the diagnosis of PAD, even after correction for clinically relevant cofounders (namely age, arterial hypertension, diabetes and LDL levels). Thusly, VCAM-1 might serve as a biomarker for PAD screening and detection.

Influences of Ivabradine treatment on serum levels of cardiac biomarkers sST2, GDF-15, suPAR and H-FABP in patients with chronic heart failure.

Chronic heart failure (CHF) represents a major cause of hospitalization and death. Recent evidence shows that novel biomarkers such as soluble suppression of tumorigenicity (sST2), growth-differentiation factor-15 (GDF-15), soluble urokinase plasminogen activator receptor (suPAR) and heart-type fatty acid binding protein (H-FABP) are correlated with inflammatory and ischemic responses in CHF patients. In this study we examined the effects of Ivabradine that inhibited the hyperpolarization-activated cyclic nucleotide-gated channel (HCN channel, also called funny current If), thereby leading to selective heart rate reduction and improved myocardial oxygen supply on the cardiac biomarkers sST2, GDF-15, suPAR and H-FABP in 50 CHF patients at the University Hospital of Jena. Patients were divided into three groups based on the etiology of CHF: dilated cardiomyopathy (DCM, n=20), ischemic cardiomyopathy (ICM, n=20) and hypertensive cardiomyopathy (HCM, n=10). The patients were administered Ivabradine (5 mg, bid for 3 months, and 7.5 mg bid for further 3 months). Analyses of cardiovascular biomarkers were performed at baseline as well as at 3- and 6-month follow-ups. At 6-month follow-up, GDF-15 levels were significantly reduced compared to baseline levels (P=0.0215), indicating a reduction in the progress of cardiac remodeling. H-FABP concentration was significantly lower in DCM patients compared to ICM (1.89 vs 3.24 µg/mL) and HCM patients (1.89 vs 3.80 µg/mL), and decreased over the 6-month follow-up (P=0.0151). suPAR median levels remained elevated, implying major ongoing inflammatory processes. As shown by significant decreases in GDF-15 and H-FABP levels, a reduction in ventricular remodeling and sub-clinical ischemia could be assumed. However, markers of hemodynamic stress (sST2) and inflammation (suPAR) showed no change or progression after 6 months of Ivabradine treatment in CHF patients. Further studies are necessary to validate the clinical applicability of these novel cardiovascular biomarkers.

Specifics of fetuin-A levels in distinct types of chronic heart failure.

INTRODUCTION: Fetuin-A has been described to correlate inversely with vascular calcification both in animal models but also in patients with heart and renal disease. In this current study, we sought to investigate whether fetuin-A might be a useful marker for the discrimination of ischemic (ICM) from dilated cardiomyopathy (DCM). METHODS: A total of 124 non-consecutive patients were included in this study, 59 patients suffered from ICM and 65 patients from DCM. Serum samples were obtained during out-patient visits and analyzed for fetuin-A by ELISA. RESULTS: Median fetuin-A concentration in the overall cohort was significantly lower in ICM patients compared to DCM patients (62.2±16.4 µg/mL vs. 129.6±56.6 µg/mL; P<.001). A positive correlation of fetuin-A levels was found with BMI, cholesterol, LDL/HDL ratio and triglycerides and an inverse correlation with age (r=-.36; P<.001). Moreover, patients suffering from (stable) angina pectoris evidenced lower fetuin-A levels compared to non-symptomatic patients (73.1±22.7 µg/mL vs. 83.7±26.2 µg/mL; P=.047) CONCLUSIONS: Fetuin-A was shown to be a potential discriminator and biomarker for the differential diagnosis between ICM and DCM. Fetuin-A levels might also be helpful in the process of diagnostic decision-making in regards to invasive management or medical therapy.

Multibiomarker analysis in patients with acute myocardial infarction.

BACKGROUND: Novel biomarkers representing different pathobiological pathways and their role in patients with acute myocardial infarction (AMI) were studied. METHODS: We retrospectively analysed serum levels of soluble suppression of tumorigenicity (sST2), growth-differentiation factor-15 (GDF-15), soluble urokinase plasminogen activator receptor (suPAR), heart-type fatty acid-binding protein (H-FABP) and plasma fetuin A in blood of patients with AMI (STEMI, n = 61; NSTEMI, n = 57) compared to controls with excluded coronary artery disease (n = 76). Furthermore, detailed correlation analysis was performed. RESULTS: Compared with controls, in patients with STEMI and NSTEMI higher levels expressed as median of sST2 in pg/mL (STEMI: 13210·9, NSTEMI: 11989·1, control: 5248; P < 0·001), GDF-15 in pg/mL (STEMI: 818·8, NSTEMI 677·5, control 548·6; P < 0·001), suPAR in pg/mL (STEMI: 3461·1, NSTEMI: 3466·7, control: 2463·6; P < 0·001), H-FABP in ng/mL (STEMI: 5·8, NSTEMI: 5·4, control: 0·0; P < 0·001) and lower plasma fetuin A levels in µg/mL (STEMI: 95, NSTEMI: 54, control: 116·6; P < 0·001) were detected. Correlation analysis found clinical and biochemical parameters such as ejection fraction, length of hospital stay, creatine kinase, NT-proBNP and hs Troponin T levels as well as inflammatory markers (CRP, leucocytes) to be significantly correlated with novel biomarkers. CONCLUSION: Plasma levels of novel biomarkers were significantly elevated (sST2, GDF-15, H-FABP, suPAR) or inversely downregulated (fetuin A) in patients with AMI compared to a control group with excluded coronary artery disease. Significant correlations with various clinical parameters and standard biochemical markers were found.

Impact of Moderate Altitude on Pro-Inflammatory Cytokines in Healthy Volunteers.

BACKGROUND: The induction of microvascular inflammation and the effects on cytokine production in blood due to hypoxia has been shown in the past. We have previously reported a statistically significant increase of the pro-inflammatory cytokine interleukin-8 (IL-8) in normobaric hypoxia in the setting of a hypoxia-chamber. In the present study, we sought to analyze plasma levels of inflammatory cytokines in a real-life stetting in order to foster our knowledge on hypoxia induced microvascular inflammation at moderate altitude. METHODS: Pro-inflammatory cytokines (IL-8, IL-6, TNF-α) were measured in an experimental field study, exposing 18 healthy volunteers to moderate hypoxia while staying at a mountain lodge in Diavolezza, Switzerland (2978 meters above sea level). Plasma cytokine levels were measured by ELISA. RESULTS: In contradiction to our results in a normobaric hypoxia-chamber, exposure to moderate hypoxia led to a significant decrease of plasma IL-8 levels in a real-life setting (from 2.902 (1.046 - 4.984) pg/mL to 1.395 (0.698 - 3.712) pg/mL, p = 0.034). Concentrations of IL-6 and TNF-α did not show statistically significant changes in comparison to baseline measurements. CONCLUSIONS: The results of this study show a decrease of proinflammatory cytokine IL-8 in a real life setting of moderate altitude in healthy individuals. Initiation of angiogenesis or subliminal stimulus for an altitude-induced inflammatory reaction may be explanations for this unexpected finding.

Decrease in circulating plasmacytoid dendritic cells during short-term systemic normobaric hypoxia.

BACKGROUND: During exposure to high altitude, the immune system is altered. During hypoxia, an increase in interleukin (IL)-6 and high sensitivity C-reactive protein (hs-CRP), and an increase in natural killer cells and decrease in T cells in blood was shown. However, the impact of hypoxia on dendritic cells has not been investigated yet. MATERIAL AND METHODS: Twelve healthy volunteers were subjected to a transient normobaric hypoxia for 6·5 h simulating an oxygen concentration at 5500 m. During exposure to hypoxia, blood samples were collected and analysed by flow cytometrical cell sorting (FACS) for circulating myeloid (mDCs) and plasmacytoid (pDCs) DCs. Serum levels of IL-6 and tumour necrosis factor (TNF)-α were analysed. In a cell culture hypoxia chamber, blood samples were subjected to the same hypoxia and analysed regarding DCs. RESULTS: Exposure to normobaric hypoxia induced a significant decrease in circulating pDCs about 45% (P = 0·001) but not of mDC compared to baseline normoxia. Furthermore, we observed a significant increase of TNF-α about 340% (P = 0·03) and of IL-6 about 286% (P = 0·002). In cell culture experiments exposure of blood to hypoxia led to no significant changes in DCs, so that a direct cytotoxic effect was excluded. During hypoxia, we observed a transient increase in stromal-derived factor 1 (SDF-1) which is important for pDC tissue recruitment. CONCLUSIONS: We show a significant decrease in circulating pDCs during hypoxia in parallel to a pro-inflammatory response. Further studies are necessary to evaluate whether the decrease in circulating pDCs might be the result of an enhanced tissue recruitment.

Increased Number of Mast Cells in Atherosclerotic Lesions Correlates with the Presence of Myeloid but not Plasmacytoid Dendritic Cells as well as Pro-inflammatory T Cells.

BACKGROUND: Atherosclerosis is an inflammatory disease of the vessel wall promoted by different immune cells and inflammatory mediators. METHODS: In this study, 26 human plaques and 12 control vessels without atherosclerosis were immunohistochemically stained to analyze the emergence of mast cells dependent on plaque morphology and to correlate mast cell occurrence with the emergence of myeloid as well as plasmacytoid dendritic cells. Also, mast cell emergence was correlated with the number of pro-inflammatory T cells. For this, plaques were classified as stable or unstable according to established histological criteria. RESULTS: As expected, atherosclerotic lesions showed significantly higher numbers of tryptase+, chymase+, and cathepsin G+ mast cells compared to control vessels, particularly in lesions with unstable morphology. As a novel finding, we detected significant correlations between mast cells and myeloid dendritic cells (fascin, CD83, r > 0.3, p < 0.01), but not plasmacytoid dendritic cells (CD123, CD304). Also, we observed significant correlations of mast cells and different subgroups of pro-inflammatory T cells (CD3, CD8, CD161, CD25; r > 0.35, p < 0.05). CONCLUSIONS: Overall, the higher number of mast cells in plaques, particularly with unstable morphology, suggests that mast cells might be involved in the progression of atherosclerosis. The correlation of mast cells with other immune cells that are pivotal in atherogenesis, e.g., myeloid dendritic cells and pro-inflammatory T cells, also suggests an interplay leading to plaque destabilization. Therefore, modulating local mast cell function and invasion into the plaque might be a therapeutic tool for plaque stabilization.

Decrease of circulating myeloid dendritic cells in patients with chronic heart failure.

AIMS: Immunity and inflammation processes are known to be of central importance in chronic heart failure (CHF). Dendritic cells (DCs) are key players in adaptive immunity, yet their role in CHF is still unknown. The aim of this study was to investigate the circulating DCs in patients with compensated CHF. METHODS: Circulating myeloid (m) and plasmacytoid (p) DCs, as well as inflammatory cytokines interleukine (IL) 6 and IL10 were flow cytometrically analysed in peripheral blood of clinically compensated CHF patients with previously diagnosed dilated cardiomyopathy (DCM, n = 69), ischaemic cardiomyopathy (ICM, n = 49), as well as in unaffected controls (n = 51). Correlation analysis was performed between circulating DCs, cytokines and parameters of heart failure severity, such as NYHA class, the marker brain natriuretic peptide (BNP) and echocardiographic parameters of left ventricular function and dilation. RESULTS: Circulating mDCs were significantly decreased in all CHF patients, although more pronounced in DCM (0.14%, P < 0.001) than in ICM (0.18%, P = 0.043) compared to controls (0.2%). In contrast, no statistical changes were observed for pDCs. Circulating mDCs correlated with left ventricular ejection fraction (LVEF) and inversely with LV end-diastolic diameter (LVEDd) in all CHF patients. For DCM patients, an inverse correlation of mDCs with BNP was additionally observed. Circulating mDCs correlated inversely with IL6 and IL10 in all CHF patients. With the exception of IL-6 and NYHA class of DCM patients, cytokines did not significantly correlate with heart failure parameters. CONCLUSIONS: Blood mDCs are decreased in CHF patients. The reduction correlates with the severity of their HF.

Impact of Systemic Normobaric Short-Term Hypoxia on Pro-Inflammatory and Anti-Inflammatory Cytokines in Healthy Volunteers.

BACKGROUND: Hypoxia has been shown to induce a microvascular inflammation, affect the cell count of different types of immune cells, and influence cytokine production in blood. In the present study, serum levels of different cytokines were investigated to achieve insights into the effect of hypoxia on the balance of inflammation and anti-inflammation. METHODS: Pro- (IL-8) and anti-inflammatory (IL-10) cytokines were measured in an experiment exposing 12 healthy subjects (35 ± 9 yr, 176 ± 7 cm, 73 ± 16 kg, BMI 23 ± 4 kg/m2) to systemic, normobaric hypoxia in a hypoxic chamber. In this chamber oxygen was replaced by nitrogen to reach an oxygen content of 9.9% that is equivalent to an altitude of 5500 m during 7 hours. Serum cytokine concentrations were analyzed using ELISA. RESULTS: As expected, a significant decrease in peripheral oxygen saturation accompanied by a significant increase in breathing frequency and heart rate were observed in the subjects during hypoxia compared to baseline (BL). Blood leukocytes increased slightly, but significantly in the course of hypoxia. A statistically significant increase was measured for IL-8 serum level during hypoxia compared to the baseline measurements (BL 12.0 ± 1.1 pg/mL, hypoxia 16.2 ± 1.6 pg/mL, p = 0.006). For IL-10 a statistically significant decrease was measured upon hypoxia compared to baseline (BL 11.6 [6.2 - 43.31 pg/mL, hypoxia 8.3 [4.4 - 26.6] pg/mL, p = 0.016). Additionally, a significant inverse correlation was found comparing the anti-inflammatory cytokine IL-10 with the pro-inflammatory cytokine IL-8 (r = -0.69, p < 0.001). CONCLUSIONS: The results of this study demonstrate a hypoxia-induced increase in pro- and decrease in anti-inflammatory cytokines reflecting an increased pro-inflammatory status during hypoxia.

Decrease in circulating dendritic cell precursors in patients with peripheral artery disease.

Peripheral artery disease (PAD) is a common manifestation of atherosclerosis. Inflammation is important for initiation and progression of the disease. Dendritic cells (DCs) as antigen-presenting cells play an important role in the immune system. Therefore, we hypothesize that, in patients with PAD, DCPs might be reduced in blood due to their recruitment into the vascular wall and induce a proinflammatory response. The numbers of myeloid DCPs, plasmacytoid DCPs, and total DCPs were analyzed by flow cytometry in blood of patients with PAD (n = 52) compared to controls (n = 60). Femoralis plaques (n = 12) of patients who underwent surgery were immunostained for CD209 and CD83 (mDCs) as well as CD304, CD123 (pDCs), and HLA-DR. In patients with PAD, a significant decrease in mDCPs, pDCPs, and tDCPs was observed. In immunostaining, markers indicative for mDCs (CD209: 16 versus 8 cells/0.1 mm(2), P = 0.02; CD83: 19 versus 5 cells/0.1 mm(2), P = 0.03) were significantly elevated in femoralis plaques compared to control vessels. We show for the first time that mDCPs, pDCPs, and tDCPs are significantly reduced in patients with PAD. Immunohistochemical analysis unraveled that the decrease in DCPs might be due to their recruitment into atherosclerotic plaques.

Decreased regulatory T cells in vulnerable atherosclerotic lesions: imbalance between pro- and anti-inflammatory cells in atherosclerosis.

Atherosclerosis is a chronic inflammatory disease of the arterial wall in which presentation of autoantigens by dendritic cells (DCs) leads to the activation of T cells. Anti-inflammatory cells like Tregs counterbalance inflammation in atherogenesis. In our study, human carotid plaque specimens were classified as stable (14) and unstable (15) according to established morphological criteria. Vessel specimens (n = 12) without any signs of atherosclerosis were used as controls. Immunohistochemical staining was performed to detect different types of DCs (S100, fascin, CD83, CD209, CD304, and CD123), proinflammatory T cells (CD3, CD4, CD8, and CD161), and anti-inflammatory Tregs (FoxP3). The following results were observed: in unstable lesions, significantly higher numbers of proinflammatory cells like DCs, T helper cells, cytotoxic T cells, and natural killer cells were detected compared to stable plaques. Additionally, there was a significantly higher expression of HLA-DR and more T cell activation (CD25, CD69) in unstable lesions. On the contrary, unstable lesions contained significantly lower numbers of Tregs. Furthermore, a significant inverse correlation between myeloid DCs and Tregs was shown. These data suggest an increased inflammatory state in vulnerable plaques resulting from an imbalance of the frequency of local pro- and anti-inflammatory immune cells.

Transient hypoxia leads to increased serum levels of heat shock protein-27, -70 and caspase-cleaved cytokeratin 18.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a worldwide burden. We have previously shown that elevated levels of heat shock protein-27 (HSP27), -70 (HSP70), and caspase-cleaved cytokeratin 18 (ccCK-18) were found in serum of COPD patients correlating with disease severity. We hypothesized that transient hypoxia triggers the release of HSPs and ccCK-18. METHODS: Fourteen healthy volunteers were subjected to transient normobaric hypoxia in an air-conditioned hypoxia chamber simulating an oxygen concentration at an altitude of up to 5500 meters. Serum samples were evaluated for HSP27, -70, and ccCK-18. RESULTS: Baseline concentrations were 2760 pg/mL +/- 517 SEM for HSP-27, 49 pg/mL +/- 22 SEM for HSP-70, and 226 U/L +/- 20 SEM for ccCK-18. After eight hours and an altitude equivalent of 5500 meters a significant increase was recorded, depicted by serum levels of 3737 pg/mL +/- 571 SEM for HSP-27, 202 pg/mL +/- 81 SEM for HSP-70, and 244 U/L +/- 20 SEM for ccCK-18 (p < 0.05). CONCLUSIONS: These results provide an explanation for the elevated serum levels of HSP-27, HSP-70, and ccCK-18 found in COPD patients, indicating that hypoxic conditions can trigger the release of the aforementioned factors.

Effects of Angiotensin Receptor-Neprilysin Inhibitors (ARNIs) on the Glucose and Fat Metabolism Biomarkers Leptin and Fructosamine.

(1) Background: Heart failure with reduced ejection fraction (HFrEF) remains a major health burden. Angiotensin-Receptor-Neprilysin-Inhibitors (ARNIs) are an established HFrEF therapy which increases natriuretic peptide levels by inhibiting neprilysin. Leptin is a lipid metabolism parameter, which is also involved in glucose metabolism and is suggested to correlate with HF burden. While the hormone also seems to interact with neprilysin, potential associations with ARNI therapy have not been investigated yet. (2) Methods: To study this issue, we measured levels of leptin and fructosamine in consecutive 72 HFrEF patients before initiation of ARNI therapy and 3-6 months after initiation of therapy in two European centers. Biomarker levels were correlated with clinical parameters including ejection fraction, LVEF, and NYHA class. (3) Results: During a follow-up of up to 6 months, clinical parameters improved significantly (LVEF: 30.2 ± 7.8% to 37.6 ± 10.0%, (p < 0.001) and a significant improvement of the mean NYHA class with initial 32 patients in NYHA III or IV and 8 patients in NYHA class III/IV during the follow up (p < 0.001). The initial NT-proBNP levels of 2251.5 ± 2566.8 pg/mL significantly improved to 1416.7 ± 2145 pg/mL, p = 0.008) during follow up. ARNI therapy was also associated with an increase in leptin levels (17.5 ± 23.4 µg/L to 22.9 ± 29.3, p < 0.001) and furthermore, affected glucose metabolism indicated by elevation of fructosamine values (333.9 ± 156.8 µmol/L to 454.8 ± 197.8 µmol/L, p = 0.013). (4) Conclusion: while in the early phase of therapy, ARNI promotes clinical improvement of HFrEF, and it also seems to affect fat and glucose parameters, indicating significant metabolic implications of this therapy regime.

Impact of cavotricuspid isthmus ablation for typical atrial flutter and heart failure in the elderly-results of a retrospective multi-center study.

Introduction: While in the CASTLE-AF trial, in patients with atrial fibrillation and heart failure with reduced ejection fraction, interventional therapy using pulmonary vein isolation was associated with outcome improvement, data on cavotricuspid isthmus ablation (CTIA) in atrial flutter (AFL) in the elderly is rare. Methods: We included 96 patients between 60 and 85 years with typical AFL and heart failure with reduced or mildly reduced ejection fraction (HFrEF/HFmrEF) treated in two medical centers. 48 patients underwent an electrophysiological study with CTIA, whereas 48 patients received rate or rhythm control and guideline-compliant heart failure therapy. Patients were followed up for 2 years, with emphasis on left ventricular ejection fraction (LVEF) over time. Primary endpoints were cardiovascular mortality and hospitalization for cardiac causes. Results: Patients with CTIA showed a significant increase in LVEF after 1 (p < 0.001) and 2 years (p < 0.001) in contrast to baseline LVEF. Improvement of LVEF in the CTIA group was associated with significantly lower 2-year mortality (p = 0.003). In the multivariate regression analysis, CTIA remained the relevant factor associated with LVEF improvement (HR: 2.845 CI:95% 1.044-7.755; p = 0.041). Elderly patients (≥ 70 years) further benefited from CTIA, since they showed a significantly reduced rehospitalization (p = 0.042) and mortality rate after 2 years (p = 0.013). Conclusions: CTIA in patients with typical AFL and HFrEF/HFmrEF was associated with significant improvement of LVEF and reduced mortality rates after 2 years. Patient age should not be a primary exclusion criterion for CTIA, since patients ≥70 years also seem to benefit from intervention in terms of mortality and hospitalization.

Prophylactic rivaroxaban in the early post-discharge period reduces the rates of hospitalization for atrial fibrillation and incidence of sudden cardiac death during long-term follow-up in hospitalized COVID-19 survivors.

Introduction: While acute Coronavirus disease 2019 (COVID-19) affects the cardiovascular (CV) system according to recent data, an increased CV risk has been reported also during long-term follow-up (FU). In addition to other CV pathologies in COVID-19 survivors, an enhanced risk for arrhythmic events and sudden cardiac death (SCD) has been observed. While recommendations on post-discharge thromboprophylaxis are conflicting in this population, prophylactic short-term rivaroxaban therapy after hospital discharge showed promising results. However, the impact of this regimen on the incidence of cardiac arrhythmias has not been evaluated to date. Methods: To investigate the efficacy of this therapy, we conducted a single center, retrospective analysis of 1804 consecutive, hospitalized COVID-19 survivors between April and December 2020. Patients received either a 30-day post-discharge thromboprophylaxis treatment regimen using rivaroxaban 10 mg every day (QD) (Rivaroxaban group (Riva); n = 996) or no thromboprophylaxis (Control group (Ctrl); n = 808). Hospitalization for new atrial fibrillation (AF), new higher-degree Atrioventricular-block (AVB) as well as incidence of SCD were investigated in 12-month FU [FU: 347 (310/449) days]. Results: No differences in baseline characteristics (Ctrl vs Riva: age: 59.0 (48.9/66.8) vs 57 (46.5/64.9) years, p = n.s.; male: 41.5% vs 43.7%, p = n.s.) and in the history of relevant CV-disease were observed between the two groups. While hospitalizations for AVB were not reported in either group, relevant rates of hospitalizations for new AF (0.99%, n = 8/808) as well as a high rate of SCD events (2.35%, n = 19/808) were seen in the Ctrl. These cardiac events were attenuated by early post-discharge prophylactic rivaroxaban therapy (AF: n = 2/996, 0.20%, p = 0.026 and SCD: n = 3/996, 0.30%, p < 0.001) which was also observed after applying a logistic regression model for propensity score matching (AF: χ 2-statistics = 6.45, p = 0.013 and SCD: χ 2-statistics = 9.33, p = 0.002). Of note, no major bleeding complications were observed in either group. Conclusion: Atrial arrhythmic and SCD events are present during the first 12 months after hospitalization for COVID-19. Extended prophylactic Rivaroxaban therapy after hospital discharge could reduce new onset of AF and SCD in hospitalized COVID-19 survivors.

Recruitment of circulating dendritic cell precursors into the infarcted myocardium and pro-inflammatory response in acute myocardial infarction.

DC (dendritic cells) play an important role in the immune system. They invade peripheral tissues to detect harmful antigens, inducing a local immune response. Studies suggest that DCPs (dendritic cell precursors) might be reduced in AMI (acute myocardial infarction); however, the reason for their reduction is unknown yet. In the present study, circulating mDCPs (myeloid DCPs), pDCPs (plasmacytoid DCPs), tDCPs (total DCPs) and serum levels of TNFα (tumour necrosis factor α), IL (interleukin)-2, -4, -5, -6, -10 and -12 were analysed by flow cytometry in blood of patients with NSTEMI [non-STEMI (ST-segment elevation myocardial infarction)] (n=44) and STEMI (n=34) compared with controls with excluded CAD (coronary artery disease) (n=45). Post-mortem myocardial specimens of patients with AMI (n=12) and healthy myocardium of accident victims (n=10) were immunostained for mDCs (myeloid dendritic cells) T-cells and macrophages. Compared with controls, in patients with AMI a significant decrease in circulating mDCPs, pDCPs and tDCPs was observed (each P<0.0001). The extent of the decrease was higher in STEMI than NSTEMI patients. Serum levels were significantly higher in patients with AMI compared with controls for IL-6, -10, -12 and TNFα (each P<0.03). Immunostaining revealed significantly higher number of DCs, T-cells and macrophages (each P<0.002) in infarcted than control myocardium. We show that circulating DCPs are significantly reduced in AMI, with a pronounced reduction in STEMI patients. This was accompanied by a significant increase of inflammatory serum cytokines in patients with AMI. Immunohistochemical analysis unravelled that the reduction of circulating DCPs might be due to recruitment into the infarcted myocardium.

Sustained Impairment in Cardiopulmonary Exercise Capacity Testing in Patients after COVID-19: A Single Center Experience.

Background: Following COVID-19, patients often present with ongoing symptoms comparable to chronic fatigue and subjective deterioration of exercise capacity (EC), which has been recently described as postacute COVID-19 syndrome. Objective: To objectify the reduced EC after COVID-19 and to evaluate for pathologic limitations. Methods: Thirty patients with subjective limitation of EC performed cardiopulmonary exercise testing (CPET). If objectively limited in EC or deteriorated in oxygen pulse, we offered cardiac stress magnetic resonance imaging (MRI) and a follow-up CPET. Results: Eighteen male and 12 female patients were included. Limited relative EC was detected in 11/30 (36.7%) patients. Limitation correlated with reduced body weight-indexed peak oxygen (O2) uptake (peakV̇O2/kg) (mean 74.7 (±7.1) % vs. 103.6 (±14.9) %, p < 0.001). Reduced peakV̇O2/kg was found in 18/30 (60.0%) patients with limited EC. Patients with reduced EC widely presented an impaired maximum O2 pulse (75.7% (±5.6) vs. 106.8% (±13.9), p < 0.001). Abnormal gas exchange was absent in all limited EC patients. Moreover, no patient showed signs of reduced pulmonary perfusion. Using cardiac MRI, diminished biventricular ejection fraction was ruled out in 16 patients as a possible cause for reduced O2 pulse. Despite noncontrolled training exercises, follow-up CPET did not reveal any exercise improvements. Conclusions: Deterioration of EC was not associated with ventilatory or pulmonary vascular limitation. Exercise limitation was related to both reduced O2 pulse and peakV̇O2/kg, which, however, did not correlate with the initial severity of COVID-19. We hypothesize that impaired microcirculation or limited peripheral O2 utilization might be causative for prolonged deterioration of EC following acute COVID-19 infection.

A new player in the game: treatment with antagomiR-21a-5p significantly attenuates histological and echocardiographic effects of experimental autoimmune myocarditis.

AIMS: Myocarditis is associated with formidable symptoms and increased risk of adverse outcomes. Current approaches mostly rely on symptomatic treatments, warranting novel concepts for clinical practice. The aim of this study was to investigate the microRNA (miRNA) expression profile of Balb/c mice with experimental autoimmune myocarditis (EAM), choose a representative miRNA to antagonize after review of available literature and test its effects on myocardial inflammation in vitro and in vivo. METHODS AND RESULTS: Phase 1: EAM was induced in 12 male Balb/c mice, 10 animals served as controls. After sacrifice, next-generation sequencing (NGS) of the miRNA expression profile was performed. Based on these results, H9C2 cells and human ventricular cardiac fibroblasts exposed to lipopolysaccharide (LPS) were treated with the selected candidate antagomiR-21a-5p. Phase 2: EAM was induced in 48 animals. Thereof, 24 animals were either treated with antagomiR-21a-5p or negative control oligonucleotide in a nanoparticle formulation. Transthoracic echocardiography (TTE) was performed on Days 0, 7, 14, and 21. Histopathological examination was performed after sacrifice. Phase 1: EAM resulted in a significant up-regulation of 27 miRNAs, including miR-21a-5p (log2FC: 2.23, adj. P = 0.0026). Transfection with antagomiR-21a-5p resulted in a significant reduction of TNFα, IL-6, and collagen I in vitro. Phase 2: Treatment with antagomiR-21a-5p, formulated in polymeric nanoparticles for systemic injection, significantly attenuated myocardial inflammation (P = 0.001) and fibrosis (P = 0.013), as well as myocardial 'hypertrophy' on TTE. CONCLUSIONS: Silencing of miR-21a-5p results in a significant reduction of the expression of pro-inflammatory cytokines in vitro, as well as a significant attenuation of inflammation, fibrosis and echocardiographic effects of EAM in vivo.