Severe COVID-19 and its cardiopulmonary effects 6 and 18 months after hospital discharge

Introduction

SARS-CoV-2 infection affects the cardiopulmonary system in the acute as well as long-term phase. The aim of the present study was to comprehensively assess symptoms and possible long-term impairments 6 and 18 months after hospitalization for severe COVID-19 infection.

Methods

This prospective registry included patients with PCR-confirmed COVID-19 infection requiring hospitalization. Follow-up approximately 6 months post discharge comprised a detailed patient history, clinical examination, transthoracic echocardiography, electrocardiogram, cardiac magnetic resonance imaging (cMRI), chest computed tomography (CT) scan, pulmonary function test (PFT), six-minute walk test (6MWT) and a laboratory panel. At the time of the second follow-up visit at 18 months, patients without pathologic findings during the first study visit were contacted by phone to inquire about the course of their symptoms. In all other patients all initial examinations were repeated.

Results

Two hundred Patients, who were hospitalized for COVID-19, were contacted by phone and were recruited for the study. Due to dropouts the second study visit was performed in 170 patients. A comparison between the two study visits at 6 and 18 months post discharge showed the following results: Six months after discharge, 73% and 18 months after discharge 52% fulfilled the criteria for Long COVID with fatigue being the most common symptom (49%). Echocardiography at 6 months post discharge showed an impaired left ventricular function in 8% of which 80% returned to normal. Six months post discharge, cMRI revealed pericardial effusion in 17% which resolved in 47% of the 15 patients who underwent a control cMRI. Signs of peri- or myocarditis were present in 5% of the patients and were resolved in all 4 patients who attended control studies. At 6 months, chest CT scans identified post-infectious residues in 24%. In the 25 repeated chest CT scans 20% showed full recovery. Length of in-hospital stay was identified as a significant predictor for persisting Long COVID (95% CI: 1.005-1.12, p = 0.03).

Conclusion

Comparing 6 to 18 months, the prevalence of Long COVID decreased over time, but a high symptom burden remained. Structural and functional abnormalities were less frequent than the portrayed symptoms, and it thus remains a challenge to substantiate the symptoms.

Impact of dexamethasone on cardiac injury in critically ill COVID-19 patients

Aims/Background

Severe COVID-19 pneumonia requiring intensive care treatment remains a clinical challenge to date. Dexamethasone was reported as a promising treatment option, leading to a reduction of mortality rates in severe COVID-19 disease as well as ventilator-dependent days. However, the effect of dexamethasone treatment on cardiovascular outcomes including cardiac injury monitored by cardiac enzymes remains largely elusive.

Methods

For this study, we retrospectively screened 224 consecutive COVID-19 patients between 4/2020 and 1/2021 in three Europeen Hospitals. To avoid bias effects of further applied COVID-19 specific medications including tacilizumab, remdesevir and sarilumab, 46 patients treated with at least one of these substances were excluded from further analyses. In total 178 critically ill COVID-19 patients requiring intensive care treatment and mechanical ventilation were recruited. 113 patients (63.5%) were treated with dexamethasone for a median duration of 10 days (IQR 9–10). 65 patients (36.5%) constituted the non-dexamethasone group. The assessment of cardiac injury was based on cardiac enzymes.

Results

Baseline charactaristics shown in Tab. 1. While peak inflammatory markers seemed to be reduced by dexamethasone treatment (CRP and a trend towards decrease of interleukin 6 levels (CRP maximum level: median: 20 ng/mL (IQR 12–28) vs. 22 ng/mL (IQR 14–37), p=0.043; IL-6 maximum level: median: 192 pg/mL (IQR 78–533) vs. 708 pg/mL (550–885), p=0.085), in the dexamethasone Group also shown a significant reduction in peak troponine levels as shown in Figure 1. CK and CK-MB do not differ significantly by Dexamethasone application. Of note, no significant changes in baseline characteristics were observed between the dexamethasone and non-dexamethasone group (Table 1).

Conclusion

In severe COVID-19, antiinflammatory effects of dexamethasone treatment could be associated with a significant reduction in myocardial injury. Further studies should further evaluate whether Dexamethasone effects directly myocardial involvement in COVID 19.

Funding Acknowledgement

Type of funding sources: None.

Analysis of novel cardiac biomarkers in diagnosis of decompensated heart failure

Aims

Heart failure (HF) remains a major therapeutic and diagnostic challenge. In this study we aimed to analyze the predictive potential of four novel cardiovascular biomarkers – soluble urokinase-type plasminogen activator receptor (suPAR), vascular cell adhesion molecule (CAM-1), heart-type fatty acid binding Protein (H-FABP) and growth/differentiation factor 15 (GDF-15) in detecting cardiac decompensation in patients with HF.

Methods

In total, 136 patients (40 decompensated HF, 96 compesated HF) were retrospectively enrolled and the serum biomarker concentrations of GDF-15, suPAR, H-FABP and CAM-1 were analyzed by Enzyme Linked Immunosorbent Assay (ELISA). Biomarker concentrations were correlated with clinical and biochemical parameters of enrolled patients, the predictive value for detecting cardiac decompensation was assessed by ROC-plots, as well as univariate and multivariate logistic regression analysis. Cut-offs for cardiac decompensation were calculated by means of the Youden index.

Results

A significant increase in the levels of suPAR (1.6-fold change, p<0.0001), CAM-1 (1.6-fold change, p<0.0001), HFABP (2.2-fold change, p=0.0458) and GDF-15 (1.7-fold change, p=0.0009) was detected in all patients with decompensated HF compared to patients with compensated HF. In univariate logistic regression analysis, plasma concentrations of GDF-15, H-FABP, suPAR and CAM-1 were significantly associated with the risk for cardiac decompensation. For GDF-15, suPAR and CAM-1, this association remained significant even after correction for confounders in a multivariate logistic regression analysis. Additionally, AUCs (GDF-15: 0.759, 95% (0.683–0.866), suPAR: 0.838, 95% (0.750–0.926), CAM-1: 0.838, 95% (0.750–0.926)) and optimal cut-offs (GDF-15: 1404.8835 pg/ml, suPAR: 4774.027 pg/ml, CAM-1: 4.74027 ng/ml) of the biomarkers were calculated. Correlation analyses found clinical and biochemical parameters such as creatinine as well as inflammatory marker CRP to be significantly correlated with novel biomarkers (r>0.3, p<0.001. In conjunction with the results for the AUC of NTproBNP (AUC=0.785), suPAR (AUC=0.838) and CAM-1 (AUC=0.838 more accurately prediced cardiac decompensation in heart failure than NTproBNP (Figure 1).

Conclusion

In conclusion, the investigated novel cardiovascular biomarkers could be a valuable tool to facilitate therapeutic decisions in patients with HF and suspicion of cardiac decompensation. Parameters such as renal function should be taken into account.

Funding Acknowledgement

Type of funding sources: None.

Effects of angiotensin receptor-neprilysin inhibitors (ARNIs) on the glucose and fat metabolism biomarkers leptin and fructosamin

Background

Heart Failure with reduced ejection fraction (HFrEF) has a life time risk about 20% among adults aged 40 years or older and a 5-year mortality rate about 60% [1,2]. However novel therapies have shown to improve this outcome. One novel agent are angiotensin receptor-neprilysin inhibitors (ARNIs) that increase the BNP levels via inhibiting neprilsyin [3]. This has beneficial effects on heart failure by reducing preload, inflammation and fibrosis. Neprilysin also interacts with leptin and is known to correlate with the incidence and progression of heart failure if chronically elevated [4]. Furthermore beneficial affects of ARNI therapy on glucose metabolism were reported in a post-hoc analysis of the PARADIGM-HF trial [5]. In this study we aim to investigate the effect of ARNI therapy on the fat metabolism markers leptin and on the glucose metabolism marker fructosamin.

Methods

In total, we included 74 patients with HFrEF with ischemic (N=37) and non-ischemic (n=37) origin in the present study. The mean NYHA class was II–III, the mean BMI 28 (SD 6.3). Patients had well established heart failure therapy before starting ARNI therapy with sacubitril/valsartan. 88% of patients were on ACE-inhibitors, 86% on beta blockers and 68% on mineralocorticoid receptor antagonists. Serum samples were obtained and analyzed for leptin, fructosamin and pBNP before and 3–6 month after ARNI therapy. The clinical parameters LVEF and NYHA class were assessed before and 3–6 month after ARNI therapy.

Results

Baseline leptin level was 15.0 (SD 17.2), baseline fructosamin level was 370.1 (SD 167.7) and baseline pBNP level was 1494.9 (SD 1281.4). Under therapy a significant improvement of ejection fraction from 29,8% to 37,5% (7,7 SD 8,5 P≤0.001), an improvement of NYHA stadium from 2.46 (SD 0.62) to 1.96 (SD 0.63, p=0.005) and a significant decrease of pBNP (562.1 SD 1256.4, p=0.018) was found. Along with that, a significant increase in leptin levels (3.6 SD 8.85, p=0.012) and a significant increase in fructosamine levels (93.5 SD 160.6, p=0.013) was shown.

Conclusion

Under therapy with ARNI we showed a sufficient therapy response with improvement of ejection fraction and decrease of pBNP in line with literature. Surprisingly metabolism biomarkers did significantly worsen under the first three to six month after new ARNI therapy. To distinguish between a side effect of ARNI therapy or consequence of heart failure itself further investigations are needed.

Funding Acknowledgement

Type of funding sources: None.

Prognostic impact of cavotricuspid isthmus ablation for typical atrial flutter in patients with heart failure and reduced ejection fraction

Background

The CASTLE-AF trial in 2018, showed that pulmonary vein isolation provides a survival benefit and a reduced hospitalization rate in patients with heart failure and concomitant atrial fibrillation. Typical atrial flutter (AFL) can also induce heart failure (tachymyopathy) or, if cardiomyopathy of other origin is prevalent, can further worsen it. Cavotricuspid isthmus ablation (CTI) is a simple, invasive electrophysiological procedure that can effectively treat AFL. Prognostic data on the impact of CTI in patients with heart failure and reduced ejection fraction (HFrEF) is lacking.

Purpose

This study focused on the analysis of the clinical impact of CTI vs. medical therapy in patients with HFrEF.

Methods

The present retrospective, international, multi-center study included 104 patients <85 years with AFL and heart failure (LVEF <50%). 64 patients underwent an electrophysiological study with successful CTI (ablation group), whereas 40 patients received medical therapy alone with frequency or rhythm control and guideline-compliant heart failure therapy (medical therapy group). Patients were followed up for a total of 2 years, with particular emphasis on recording the change in LVEF over time. The primary endpoints were cardiovascular mortality and hospitalization for cardiac causes.

Results

Patients after CTI showed a significant increase in LVEF after 1 year (with the exception of valvular cardiomyopathy). The optimization of LVEF was also reflected in the Kaplan-Meier curves, as the ablation group had a significantly lower 2-year, cardiovascular mortality (p<0.001). The hospitalization rate for cardiac causes in the overall cohort showed a tendency towards reduced hospitalizations (p=0.072). Elderly patients also benefited from CTI in this study. Specifically, Patients ≥70 years of age showed a significantly lower re-hospialization rate after CTI (p=0.043) as well as a significantly reduced mortality after 2 years (p=0.012).

Conclusions

CTI in patients with AFL and HFrEF was associated with significant optimization of LVEF and lower rates of hospitalization and mortality after 2 years. Patient age should not be a primary exclusion criterion for CTI because in this study, patients ≥70 years also benefited significantly from intervention in terms of mortality and hospitalization.

Funding Acknowledgement

Type of funding sources: None.

Agomir of miRNA-30d – a potential new therapeutic target for prevention of ischemic cardiomyopathy after myocardial infarction?

Background

MicroRNA (miR)-30d is not only a valuable biomarker for assessing the extent of cardiac remodeling after myocardial infarction (MI), but also an important predictor of clinical outcome in heart failure. Overexpression of miRNA-30d appears to have a cardioprotective effect by preventing cardiomyocyte apoptosis as well as averting cardiac fibroblast proliferation via multiple molecular pathways. The aim of the present in vivo and in vitro study was to demonstrate whether an miR-30d can be a potential therapeutic target to reduce the risk of ischemic cardiomyopathy (iCMP) after MI.

Methods

First of all, miRNA profiling was performed by next generation sequencing (NGS) to assess differences in miRNA expression in ischemic vs. healthy myocardium in a rat model of MI using coronary artery ligation (ischemia/reperfusion injury, IR). MiR-30d was selected as the most promising target as it was significantly downregulated in ischemic myocardium and can be upregulated by cardioprotective agents. Therefore, an agomir of miR-30d was administered in the respective treatment group intraperitoneally, whereas non-functional, scrambled miRNA was administered in the control group. To analyze the ratio between phosphorylated p53 (pp53) and total p53, apoptosis was evaluated in human cardiomyocytes using a p53 and pp53 ELISA kit. To gain indirect insight into infarct healing, scratch assays were used to obtain information on cell migration in human umbilical vein endothelial cells (HUVEC) in vitro. Six weeks after the in vivo induction of acute MI/IR with consequential iCMP in a rat model, the extent of MI was evaluated by planimetry.

Results

The majority of miRNAs studied here showed significant up-regulation in the MI-induced heart tissue in comparison to the sham operated controls. In contrast, miRNA-30d was highly significantly reduced (p<0.001). Based on these investigations and the already repeatedly documented cardioprotective effect of miR-30d overexpression, an agomir was selected as a potential therapy target. Human cardiomyocytes under the influence of an agomir of miR-30d showed a decreased pp53/total p53 ratio (0.66±0.09 vs. 0.81±0.19) and thus a distinct tendency (p=0.055) for a reduction in apoptotic rate compared to the control group. In HUVECs, gap closure was significantly faster in the agomir treated cells 20h and 26h post-scratching (19.1% more than scrambled control after 20h; p=0.0028 and 18.7% more than scrambled control after 26h; p=0.0081). In the in vivo model, infarct size of left ventricle was significantly reduced by using the agomir (7.43±4.13% vs. 12.76±4.76%; p=0.0172).

Conclusion

Using an agomir of miR-30d underlines the cardioprotective effects of miR-30d in MIR/IR and could reduce the risk for iCMP development. Further investigations regarding its therapeutic potential in the human should be considered, as microRNA treatments are gaining more and more clinical applicability today.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Paracelsus Medical University, PMU-FFF

Dexamethasone improves cardiovascular outcomes in critically ill COVID-19, a real world scenario multicenter analysis

Background

Severe COVID-19 pneumonia requiring intensive care treatment remains a clinical challenge to date. Dexamethasone was reported as a promising treatment option, leading to a reduction of mortality rates in severe COVID-19 disease. However, the effect of dexamethasone treatment on cardiac injury and pulmonary embolism remains largely elusive.

Methods

In total 178 critically ill COVID-19 patients requiring intensive care treatment and mechanical ventilation were recruited in three European medical centres and included in the present retrospective study. 113 patients (63.5%) were treated with dexamethasone for a median duration of 10 days (IQR 9–10). 65 patients (36.5%) constituted the non-dexamethasone control group.

Results

While peak inflammatory markers were reduced by dexamethasone treatment, the therapy also led to a significant reduction in peak troponin levels (231% vs. 700% indicated as relative to cut off value, p=0.001). Similar, dexamethasone resulted in significantly decreased peak D-Dimer levels (2.16 mg/l vs. 6.14mg/l, p=0.002) reflected by a significant reduction in pulmonary embolism rate (4.4% vs. 20.0%, p=0.001). The antithrombotic effect of dexamethasone treatment was also evident in the presence of therapeutic anticoagulation (pulmonary embolism rate: 6% vs. 34.4%, p<0.001). Of note, no significant changes in baseline characteristics were observed between the dexamethasone and non-dexamethasone group.

Conclusion

In severe COVID-19, antiinflammatory effects of dexamethasone treatment seem to be associated with a significant reduction in myocardial injury. Similar, a significant decrease in pulmonary embolism, independent of anticoagulation, was evident, emphasizing the beneficial effect of dexamethasone treatment in severe COVID-19.

Funding Acknowledgement

Type of funding sources: None.

Cardiopulmonary long-term effects in patients after hospitalization due to COVID-19 infection

Background

Multiple studies have described acute effects of the Covid-19 infection on the heart, but little is known about the long-term cardiac and pulmonary effects and complications after recovery. The aim of this analysis was to deliver a comprehensive report of symptoms and possible long-term impairments after hospitalization because of Covid-19 infection as well as to try to identify predictors for Long-Covid.

Methods

This was a prospective, multicenter registry study. Patients with verified Covid-19 infection, who were treated as in-patients at our dedicated Covid hospital (Clinic Favoriten), have been included in this study. In all patients, testing was performed approximately 6 months post discharge. During the study visit the following tests and investigations were performed: detailed patient history and clinical examination, transthoracic echocardiography, electrocardiography, cardiac magnetic resonance imaging (MRI), chest computed tomography (CT) scan, lung function test and a comprehensive list of laboratory parameters including cardiac bio markers.

Results

Between July 2020 and October 2021, 150 patients were recruited. Sixty patients (40%) were female and the average age was 53.5±14.5 years. Of all patients, 92% had been admitted to our general ward and 8% had a severe course of disease, requiring admission to our intensive care unit. Six months after discharge the majority of patients still experienced symptoms and 75% fulfilled the criteria for Long-Covid. Only 24% were completely asymptomatic (figure 1).

Echocardiography detected reduced global longitudinal strain (GLS) in 11%. Cardiac MRI revealed pericardial effusion in 18%. Furthermore, cardiac MRI showed signs of former peri- or myocarditis in 4%. Pulmonary CT scans identified post-infectious residues, such as bilateral ground glass opacities and fibrosis in 22%. Exertional dyspnea was associated with either reduced forced vital capacity measured during pulmonary function tests in 11%, with reduced GLS and/or diastolic dysfunction, thus providing evidence for a cardiac and/or pulmonary cause.

Independent predictors for Long-Covid were markers of a more severe disease course like length of in-hospital stay, admission to an intensive care unit, type of ventilation as well as higher NT-proBNP and/or troponin levels.

Conclusion

Even 6 months after recovery from Covid-19 infection, the majority of previously hospitalized patients still suffer from at least one symptom, such as chronic fatigue and/or exertional dyspnea. While there was no association between fatigue and cardiopulmonary abnormalities, impaired lung function, reduced GLS and/or diastolic dysfunction were significantly more prevalent in patients presenting with exertional dyspnea. On chest CT approximately one fifth of all patients showed post infectious changes in chest CT including evidence for myo- and pericarditis as well as accumulation of pericardial effusions.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Major fund

Neutrophil-to-lymphocyte ratio and monocyte-to-lymphocyte ratio predict length of hospital stay in acute myocarditis

Background

Neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-lymphocyte ratio (MLR) are associated with the severity of various diseases, for example sepsis and coronary artery disease. So far, these ratios have not been described in patients diagnosed with myocarditis. The aim of this study was to demonstrate the relationship of NLR and MLR with the severity of acute myocarditis.

Materials and methods

224 consecutive patients with myocarditis were retrospectively enrolled in this study. Laboratory parameters and clinical data were extracted from hospital records and discharge letters.

Results

Median NLR was 2.48 (IQR 1.51–4.71) and median MLR was 0.42 (IQR 0.29–0.58). NLR and MLR correlated with HF, CRP and leukocyte count. NLR further correlated with pBNP (rs= 0.390, p=0.037) and inversely with oxygen saturation (rs=−0.620, p=0.042), whereas MLR correlated inversely with LV systolic function (rs=−0.386, p=0.018). Both ratios correlated better with length of hospital stay (NLR: rs= 0.450, p=0.001, MLR: rs= 0.547, p&lt;0.0001) than CRP, leukocyte count, troponin, CK or pBNP. In multiple linear regression analysis, a model with eGFR and MLR achieved the best predictive ability for length of stay (adj. R2= 0.61, p&lt;0.0001). AUCs for the prediction of prolonged hospital stay (NLR= 0.79, MLR= 0.82), and optimal cut-offs therefor were calculated (NLR= 4.00 (sens.: 68%, spec.: 84%), MLR= 0.48 (sens.: 79%, spec.: 78%)). Patients who met the combined endpoint of in-hospital complications showed a higher NLR, however, this remained statistically insignificant (NLR: median 3.59 (IQR 1.60–10.13) vs. 2.49 (IQR 1.51–4.60), p=0.288).

Conclusion

NLR and MLR correlated with the length of stay, as well as with several clinical and laboratory parameters in patients with myocarditis. Since white blood cell differentials are relatively easy and fast to perform, both ratios could facilitate further risk stratification in patients with acute myocarditis.

Funding Acknowledgement

Type of funding sources: None.

Long-term cardiopulmonary effects after Covid-19 infection

Introduction

The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic of 2020 has an influence on people's lives worldwide, impacting global health and putting pressure on health care systems. Multiple studies have described acute effects of the Covid-19 infection on the heart, but little is known about the long-term cardiac effects and complications after recovery. The aim of this analysis was to deliver a comprehensive report of symptoms and long-term impairment after Covid-19 infection.

Methods

This study was a prospective, multicenter registry study. Patients with verified COVID-19 infection, who were treated at our dedicated COVID hospital (Klinik Favoriten), have been included in this study. In all patients, testing was performed approximately 6 months post discharge. During each study visit the following tests and investigations were performed: detailed patient history and clinical examination, transthoracic echocardiography, electrocardiography, cardiac magnetic resonance imaging (MRI), pulmonary computed tomography (CT) scan, lung function test, spiroergometry and six-minute walk test (6MWT), and a comprehensive list of laboratory parameters including cardiac bio markers such as brain natriuretic peptide (NTpro BNP) and troponin T.

Results

In this interim analysis of an ongoing trial, the first 65 patients are presented. Baseline values are shown in table 1: 34 (59%) were male and the median age was 48.5 years (36.4–59.3). 86% of all patients included so far had an only mild to moderate course of disease and 14% of them had a severe course and were admitted to our intensive care unit. At the time of the study visit, the majority of patients still complained about symptoms: 40% presented with fatigue and weakness, 36% with exertional dyspnea, 21% with vertigo, 17% had an impaired taste or smell. Only 28% were completely asymptomatic (figure 1). From a cardiac perspective, the only abnormal findings noted in echocardiography studies were reduced left ventricular global longitudinal strain. Cardiac MRI revealed pericardial effusion in 19%, however, these were only minimal (≤9mm) and not visible in echocardiography. Furthermore, cardiac MRI showed positive late gadolinium enhancement in 11%. Pulmonary function tests were abnormal in 16%. Pulmonary CT scans showed post infectious residues like bilateral ground glass opacities and fibrosis in 45%. Exercise capacity as measured by the 6-minute walk test with BORG Dyspnea Score and by spiroergometry was reduced in almost 40% of our study participants.

Conclusions

This interim analysis showed that most previously hospitalized patients still suffer from chronic fatigue, exertional dyspnea and impaired cardiopulmonary function after Covid-19 infection. Furthermore, even though cardiac and pulmonary imaging revealed numerous pathologic findings, and exercise capacity was reduced, no correlations could be found with persisting symptoms.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Klink Favoriten and Medical University hospital Vienna

Effective reduction of scatter radiation for operator and assistant during coronary procedures with a suspended radiation protection system in a per-procedure live-dosimetry analysis

Background

Interventional cardiologists (IC) are exposed to the highest doses of radiation compared to all other medical specialties. Although head and eyes are exposed to a significant dose of scatter radiation (SCR), precise per-procedure data is sparse. Recently, the EU guidelines for maximum eye lens SCR doses have been reduced from 150 mSv to 20 mSv per year. A ceiling suspended operator radiation protection system has shown additional benefits for SCR protection in radiologic interventional procedures.

Purpose

To study the impact of the ZG system on IC and sterile assistant (SA) SCR exposure when used in addition to the current standard of X-ray protection (SXP) in unselected all-comers cardiologic procedures.

Methods

IC and SA were equipped with Unfors RaySafe i3 live-dosimeters at prespecified locations. 181 consecutive cardiac procedures were recorded, in which either both IC and SA were using SXP (lead apron, thyroid shield) or the IC was using the ZG system and the SA was wearing SXP. In all procedures a suspended lead shield, patient lead cover and an adjustable lead side-shield were present. Diagnostic angiographies (DA) and interventions (PCI) were grouped separately. Within both groups, the IC's and SA's SCR doses were compared.

Results

SCR doses were recorded in 100 DA and 81 PCI procedures. Compared to SXP, the use of the ZG device reduced the average SCR doses per procedure of the IC recorded at the left lateral head from 5.18±1.11 μSv to 0.60±0.07 μSv in DA (−88%; n=49/49, p&lt;0.0001) and from 19.64±3.36 μSv to 1.05±0.28 μSv for PCI (−95%; n=54/23, p=0.0006). The IC's average frontal dose at eye level was reduced from 1.38±0.33 μSv to 0.36±0.04 μSv in DA (−74%; n=50/50, p=0.0033) and from 3.33±0.53 μSv to 0.88±0.20 μSv in PCI (−74%; n=55/25, p=0.0031). Consistently, the dose recorded immediately under the IC's left shoulder were reduced from 34.14±7.79 μSv to 1.59±0.32 μSv in DA (−95%; n=39/40, p=0.0001) and from 71.77±10.77 μSv to 3.95±0.83 μSv in PCI (−94%; n=44/23, p=0.0001). Furthermore, when the IC used the ZG system, the average SCR dose recorded at the SA's head was reduced from 4.32±0.98 μSv to 2.11±0.28 μSv in DA (−51%, n=45/49, p=0.027) and from 18.55±2.69 μSv to 6.93±1.93 μSv in PCI (−63%, n=54/24, p=0.0078). With the exception of the IC frontal dose, all SCR dose effects remained significant after correction for total radiation time (μSv/s) and dose-area product (μSv/Gy·cm2). Procedure duration, contrast use and patient radiation dose were not affected by ZG use.

Conclusions

In a representative all-comers cohort of cardiac procedures, the ZG X-ray protection system demonstrated an impressive potential for SCR reduction in critical anatomical areas - even in a state-of-the-art cath-lab inventory with multiple SCR reduction measures already in place. Remarkably, the protective effect also included the sterile assistant at the table wearing SXP.

Funding Acknowledgement

Type of funding sources: None.

Higher incidence of stroke in severe COVID-19 is not associated with a higher burden of arrhythmias: comparison to other types of severe pneumonia

Background

Thromboembolic events, including stroke, are typical complications of COVID-19. Whether arrhythmias, frequently described in severe COVID-19, are disease-specific and thus promote strokes is unclear. We investigated the occurrence of arrhythmias, and stroke during rhythm monitoring in critically ill COVID-19, compared to severe pneumonias of other origin.

Methods

Recruited were 120 critically ill patients requiring mechanical ventilation in three European tertiary hospitals, including n=60 COVID-19, matched according to risk factors for occurrence of arrhythmias to n=60 patients from a retrospective consecutive cohort of severe pneumonias of other origin.

Results

Arrhythmias, mainly atrial fibrillation (AF), were frequent in COVID-19. However, when compared to nonCOVID-19, no difference was observed with respect to ventricular tachycardias (VT) and relevant bradyarrhythmias (VT 10.0 vs. 8.4%, p=ns and asystole 5.0 vs. 3.3%, p=ns) with consequent similar rates of cardiopulmonary resuscitation (6.7 vs. 10.0% p=ns). AF was even more common in nonCOVID-19 (AF 18.3 vs. 43.3%, p=0.003; newly onset AF 10.0 vs. 30.0%, p=0.006) which resulted in higher need for electrical cardioversion (6.7 vs. 20.0%, p=0.029). Despite these findings and comparable rates of therapeutic anticoagulation (TAC), the incidence of stroke was higher in COVID-19 (6.7.% vs. 0.0, p=0.042). These events happened also in absence of AF (50%) and with TAC (50%).

Conclusion

Arrhythmias were common in severe COVID-19, consisting mainly of AF, yet less frequent than in matched pneumonias of other origin. A contrasting higher incidence of stroke independent of arrhythmias observed also with TAC, seems to be an arrhythmia-unrelated disease-specific feature of COVID-19.

Funding Acknowledgement

Type of funding sources: None.

Kynurenine as a potential biomarker in detecting reduced muscle endurance: metabolomic profiling of patients with heart failure and exercise intolerance

Aims

Reduced muscle endurance (RME) in patients with HFpEF and HFrEF is associated with structural and metabolic changes in skeletal muscle. We investigated the role of kynurenine (Kyn) as a potential marker in detecting RME. Additionally, we described the likely distorted metabolic pathways in serum in patients with RME and both preserved (HFpEF) and reduced (HFrEF) ejection fraction.

Methods

Fifty-five participants were prospectively recruited (17 HFpEF, 18 HFrEF outpatients and 20 healthy controls, HC). All participants underwent echocardiography, CPET, isokinetic muscle function tests. Quantification of metabolites in serum was performed using liquid chromatography tandem mass spectrometry.

Results

In a linear regression, Kyn was an independent predictor for RME after adjusting for alanine, glutamate, ornithine, spermine and short-chain-ACs (B: −8.2 per 1μM increase, 95% CI: −13.01, −3.30, p=0.001). Kyn showed 83% sensitivity and 70% specificity (area under the curve 0.83) in detecting RME. Patients with RME and HFpEF showed reduced levels of long-chain-, medium-chain-, medium-/long-chain-ACs ratios and alanine (p&lt;0.05). In patients with RME and HFrEF we observed reduced concentrations of AAs (p&lt;0.05). Compared to HC, patients with HFpEF and HFrEF had reduced amino acid (AA)-concentrations except for branched-chain and aromatic AAs, and higher concentrations of acylcarnitines (ACs) and Kyn (p&lt;0.05).

Conclusions

Kyn shows high potential as biomarker for detecting RME. RME was associated with impaired fatty acid oxidation rates in HFpEF patients and with reduced concentrations of AAs in those with HFrEF.

Funding Acknowledgement

Type of funding sources: None.

Is basic science falling behind? A mixed methods study of bibliometric data and expert interviews in the field of cardiovascular research

Introduction

Scientists in the field of cardiovascular research face many difficulties today and find themselves under considerable pressure to be successful with their projects and publish their results on a regular basis (the publish or perish aphorism).

Purpose

The objective of this mixed methods study that included quantitative and qualitative research methods was to analyse prospects of scientific success and how scientists see opportunities, risks and how they try to adapt to the current publication system.

Methods

An analysis of all publications that were published by our department in the years 2014–2019 (total of 104 publications) was performed. Publications were allocated to the sub-categories basic science, clinical science, register studies/database studies and others (letters, reviews, editorials). Further specific characteristics (impact factor, number of authors/institutions, utilization of an animal model and project costs) were also collected.

Furthermore, a total of 14 interviews with experts in the field of cardiovascular research were conducted. Interviews were recorded and transcribed. For quantitative text analysis MaxQDA software and the method proposed by Philipp Mayring was used.

Results

When analysing the publication output of our department we found that achieved impact factors points were equally distributed between basic science, clinical science and register/database studies. Project costs were considerable higher for basic science studies compared to clinical studies and even more to register/database studies (p=0.0001). A correlation between costs and impact factor was found for basic science studies only (r=0.66, p=0.004). A multivariable regression analysis showed that project costs, number of authors and the use of an animal model, but not the number of institutions, was associated with a higher impact factor.

Experts in the field shared the opinion that it might be “easier” to be successful with clinical science studies as they require less resources such as grant money, personnel and technical equipment. Moreover, upcoming risks such as competition for grant money, pressure to publish results, inadequacy of the impact factor system, securing ones job, rising publication costs and more pressure of time due to patient care, research and teaching duties for academic personnel were also highlighted to worsen the situation.

Conclusion

Based on own data and the views of experts it seems much more effort- and cost-efficient to pursue projects in clinical science. Researchers in the current academic system are pressured by multiple risks. After interpretation of the obtained quantitative and qualitative material, one could hypothesize that it might be easier to be successful with focussing on clinical studies when starting ones research career. These data give support to the concerns that the field of basic science might fall behind and less young scientists would opt for a career path in this field.

Funding Acknowledgement

Type of funding source: None

sST2 is a promising biomarker in hypertensive patients undergoing renal denervation

Introduction

Therapy resistant arterial hypertension (raHTN) is a major clinical burden. While therapeutic alternatives are still missing, novel interventional procedures like renal denervation (RD) are still evolving. Indeed, despite discoursing results of the Simplicity HTN-3 trial, new promising results resulted in a revival of this procedure. Therefore, predictors for the success of future interventions would be of great clinical benefit. The novel biomarker sST2 shows promising results for risk stratification of cardiovascular patient. While, sST2 belongs to the IL-1 receptor family, it has an influence on immunologic processes with consequent cardioprotective effects including prevention of myocardial hypertrophy and fibrosis indicating predictive potential in hypertensive heart disease. Nevertheless, clinical implementation of this promising biomarker was not investigated in patients with raHTN undergoing RD.

Purpose

To investigate a potential clinical relevance of sST2 in patients with raHTN undergoing RD.

Methods

We evaluated 58 patients with raHTN (age: 63±11 years, systolic blood pressure at baseline: 178±24mmHg) undergoing bilateral RD. If available, serum levels of sST2 were analyzed at baseline as well as at follow-up at one and/or three month.

Results

While RD was able to decrease blood pressure levels after one month (systolic blood pressure at one month: 158±21mmHg, p&lt;0.01), on echocardiography a reduction of left ventricular mass (LVM) was observed at one month with a further significant reduction at three month (LVM at baseline: 233±68g, LVM at one month: 218±59g and LVM at three month: 181±59, p&lt;0.01). This observation was accompanied by a significant decrease of sST2 levels at three month (sST2 baseline: 6322±3578pg/ml vs. sST2 three month: 4704±1586pg/ml, p=0.02). Furthermore, baseline sST2 was positively correlated with systolic blood pressure at one month, measured either at office (r=0.57, p&lt;0.01) or invasively in the aorta (r=0.49, p=0.03) indicating a potential predictive value of this biomarker.

Conclusion

In patients with raHTN, RD is associated with a significant decrease of sST2 levels, indicating sST2 to be involved in remodeling processes after RD. Furthermore, sST2 levels at baseline might be a potential predictor of intervention success of RD. Further, studies need to investigate the association of sST2 levels and RD.

Funding Acknowledgement

Type of funding source: None

Association of leptin serum concentration with heart adipose tissue and parameters of systolic and diastolic function in heart failure patients

Aims

Leptin has recently been related to myocardial remodeling in animal experimentation studies on heart failure (HF). Furthermore, leptin has been reported to be related to diastolic dysfunction, however only in healthy population. With the emergence of new medical therapies targeting cardiac remodeling, there needs to be a better understanding of the metabolic pathways involving leptin. Our study aims to investigate leptin's correlation to parameters of systolic and diastolic heart function, as well as epicardial and pericardial adipose tissue (EAT and PAT) in heart failure (HF) patients.

Methods

The study included 51 patients with chronic heart failure with reduced ejection fraction (HFrEF) of ischemic (n=22) and non-ischemic (n=29) origin (NYHA II-III, mean EF 29.56%, SD 8.1; mean BMI 28.08, SD 5.8). Serum concentrations of leptin, NT-proBNP, HbA1c, LDL, and total cholesterol were also measured. Global longitudinal strain (GLS) and other LV function parameters were assessed in transthoracic echocardiography, as well as EAT and PAT in parasternal long and short-axis views.

Results

We found a significant correlation between leptin serum concentration and epicardial, as well as pericardial adipose tissue (EAT r=0.336, p=0.030; PAT r=0.565, p&lt;0.001). There was a significant negative correlation between leptin and GLS (r=−0.332; p=0.045), as well a positive correlation between Leptin and E/E' ration (r=0.373; p=0.039). There was no significant difference between ischemic and non-ischemic HF patients.

Conclusion

We provide evidence of serum leptin correlation to remodeling parameters, as well as epicardial and pericardial fat tissue in HF patients. Whether leptin has positive effects on reversing or preventing remodeling in heart failure, needs further investigation.

Correlation of leptin vs. GLS

Funding Acknowledgement

Type of funding source: None

P1056Left atrial and left atrial appendage ejection fraction assessed by preprocedural cardiac CT are useful parameters for predicting the outcome of pulmonary vein isolation

Introduction

Pulmonary vein isolation (PVI) is an effective but complex treatment option for atrial fibrillation (AF). Therefore preprocedural outcome prediction is of special interest. Left atrial volume (LAVmax) is a commonly used predictor for recurring arrhythmia. Several studies have investigated different parameters for the prediction of sustained rhythm control. We hypothesized that left atrial and left atrial appendage ejection fraction (LAEF & LAAEF) assessed by high-resolution CT-imaging are even more sensitive predictors of the outcome of PVI than LAVmax.

Methods

All patients who underwent PVI between 2015 and 2018 with available preinterventional cardiac CT were included in this retrospective study and separated into 2 groups: Group A comprises all patients with sinus rhythm (SR) at follow-up and group B all patients in whom recurrence of AF was observed. Volumetric analysis of the left atrium was performed in ventricular systole (30%-Phase of the cardiac cycle) and diastole (0%-Phase). Obtained data were used to calculate left atrial and left appendage ejection fractions (LAEF & LAAEF). Success of pulmonary vein isolation was defined as clinical freedom of symptomatic AF together with sinus rhythm on the available Holter-ECG recordings during follow-up examinations. Uni- and multivariate logistic regression models and NAMS RMLE tests were used to compare LAVmax to these functional parameters.

Results

In total 152 patients with symptomatic paroxsymal or persistent AF underwent PVI at our hospital from 2015 to 2018. Due to inconsistencies in archiving in our PACS-system, 98 patients had to be excluded from analysis. Four patients were excluded due to motion artifacts. 50 patients were included in the final study (41 patients without and 9 patients with recurring AF on average 254 days after ablation). Significant differences in means were found for all assessed parameters. LAEF (accuracy 94%, sensitivity 67%) and LAAEF (accuracy 90%, sensitivity 67%) had a higher sensitivity than LAVmax (accuracy 86%, sensitivity 33%), though not significant in this study population (p = 0.18). LAVmax and LAEF in combination improved sensitivity significantly from 33% to 78% (p = 0.046). Measurements on cardiac-CT showed an excellent interobserver-reliability.

Conclusion

Reduced LAEF and LAAEF were found to be significant predictors of the outcome of PVI. Furthermore we found a trend that these functional parameters might be more sensitive than LAVmax. Thus we propose that left atrial function, assessed with preprocedural cardiac CT, offers important prognostic information for successful PVI.

Abstract Figure. Surface rendering of LA and LAA

P6287Analysis of novel cardiac markers sST2 and IL-33 in chronic heart failure with reduced ejection fraction

Background

Soluble (s) ST-2 has been recently evaluated as a monitoring parameter in heart failure (HF). Besides being a marker for cardiac strain and hemodynamic stress, studies also found an influence of ST2 on the immune system, above all mediated through its Janus-Face ligand IL-33, an alarmin released under stress conditions or by cellular death. In contrast to sST2, the role of IL-33 in HF is yet unknown.

Objective

In this project, we aimed for an analysis of the ST2/IL33 pathway in patients with heart failure with reduced ejection fraction (HFrEF).

Methods

In total, 200 patients were included in the study: 59 with ischemic (ICM), 65 with dilated (DCM) cardiomyopathy (mean LVEF 38%), as well as 76 control patients without coronary artery disease or signs of heart failure. Serum samples were analyzed by use of ELISA after informed consent.

Results

sST2 showed a significant elevation in all HF patients (p<0.0001) compared to the control group. No significant differences in levels of sST2 were observed between ICM and DCM patients. In contrast to sST2, no differences between HF patients and control group were observed for IL-33. Furthermore, sST2 showed a significant correlation with CRP (p<0.001, r=0.28), NT-pro-BNP (p<0.0001, r=0.40) and an inverse correlation with ejection fraction (p<0.0001, r=−0.40). Additionally, sST2 showed a significant elevation in patients in NYHA stages I-II (p=0.030) and NYHA stages III-IV (p<0.01). Again, no significant correlations were observed between IL-33 and parameters mentioned above.

Analysis of sST2 in heart failure

Conclusions

We observed a significant increase and correlation with disease severity of sST2 in chronic HFrEF patients of both ischemic and non-ischemic origin, but contrary to our expectations, no significant changes in serum levels of IL-33. Thus, a mechanism independent of ST2/IL33 axis could be responsible of sST2 secretion in HF. Further studies including acute decompensated patients could provide a better understanding of the IL-33 role in HF.

P3668In non-critically ill patients suffering from endocarditis partial oral antibiotic therapy is non-inferior to intravenous therapy

Introduction

Antibiotic treatment for infective endocarditis is paramount typically consisting of intravenous therapy for up to eight weeks leading to long hospital stays. This often is associated with reduced quality of life for patients and might heighten complication rates. Recently, several trials evaluating the efficacy of partial oral treatment (switching to an oral antibiotic after an initial intravenous therapy for stabilization) versus an intravenous therapy were published. We here meta-analyze all available data.

Methods and results

Overall after screening 1848 studies at title and abstract level four studies including a total of 788 patients were included. Heterogeneity was assessed using the I2 statistic. Primary endpoint was all-cause mortality, secondary endpoint endocarditis relapse. Pooled event rates were obtained for each subset of studies and combined in a fixed-effect meta-analysis, and odds ratios were calculated using a fixed-effects model (Mantel-Haenszel).

A total of 765 patients suffered from primary left-sided endocarditis. From right-sided endocarditis suffered 72 patients. All treatment regimes were adjusted to susceptibility testing. Included patients were evaluated clinically and non-critically ill.

Rate of mortality was lower in partial oral versus intravenous strategy (OR 0.34 95% CI 0.17–0.68; p=0.003; I2 30%): In partial oral group, 11 of 379 patients died, whereas in the intravenous group, 33 of 409 patients died. Endocarditis relapse rates were not dissimilar between intravenous versus oral group (OR 0.55 95% CI 0.26–1.20; p=0.13; I2 0%) with, 10 of 459 patients in the partial oral group and 18 of 456 patients in the intravenous group evidencing a relapse.

Conclusion

Partial oral therapy is non-inferior to intravenous therapy with regards to endocarditis relapse in non-critically-ill patients suffering from both left- and right-sided endocarditis. In this meta-analysis, partial oral therapy was associated with lower mortality rates. This finding certainly needs validation in further future randomized trials comparing partial oral versus intravenous antibiotic treatment in non-critically-ill patients. As partial oral therapy allows shorter hospitalization it might be preferable and improve both quality of care and patients quality of life.

Long-QT syndrome-associated caveolin-3 mutations differentially regulate the hyperpolarization-activated cyclic nucleotide gated channel 4

Background

Caveolin-3 (cav-3) mutations are linked to the long-QT syndrome (LQTS) causing distinct clinical symptoms. Hyperpolarization-activated cyclic nucleotide channel 4 (HCN4) underlies the pacemaker current If. It associates with cav-3 and both form a macromolecular complex.

Methods

To examine the effects of human LQTS-associated cav-3 mutations on HCN4-channel function, HEK293-cells were cotransfected with HCN4 and wild-type (WT) cav-3 or a LQTS-associated cav-3 mutant (T78M, A85T, S141R, or F97C). HCN4 currents were recorded using the whole-cell patch-clamp technique.

Results

WT cav-3 significantly decreased HCN4 current density and shifted midpoint of activation into negative direction. HCN4 current properties were differentially modulated by LQTS-associated cav-3 mutations. When compared with WT cav-3, A85T, F97C, and T78M did not alter the specific effect of cav-3, but S141R significantly increased HCN4 current density. Compared with WT cav-3, no significant modifications of voltage dependence of steady-state activation curves were observed. However, while WT cav-3 alone had no significant effect on HCN4 current activation, all LQTS-associated cav-3 mutations significantly accelerated HCN4 activation kinetics.

Conclusions

Our results indicate that HCN4 channel function is modulated by cav-3. LQTS-associated mutations of cav-3 differentially influence pacemaker current properties indicating a pathophysiological role in clinical manifestations.

Irradiated cultured apoptotic peripheral blood mononuclear cells regenerate infarcted myocardium

BACKGROUND

Acute myocardial infarction (AMI) is followed by post AMI cardiac remodelling, often leading to congestive heart failure. Homing of c-kit+ endothelial progenitor cells (EPC) has been thought to be the optimal source for regenerating infarcted myocardium.

METHODS

Immune function of viable peripheral blood mononuclear cells (PBMC) was evaluated after co-culture with irradiated apoptotic PBMC (IA-PBMC) in vitro. Viable PBMC, IA-PBMC and culture supernatants (SN) thereof were obtained after 24 h. Reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay were utilized to quantify interleukin-8 (IL-8), vascular endothelial growth factor, matrix metalloproteinase-9 (MMP9) in PBMC, SN and SN exposed fibroblasts. Cell suspensions of viable- and IA-PBMC were infused in an experimental rat AMI model. Immunohistological analysis was performed to detect inflammatory and pro-angiogenic cells within 72 h post-infarction. Functional data and determination of infarction size were quantified by echocardiography and Elastica van Gieson staining.

RESULTS

The IA-PBMC attenuated immune reactivity and resulted in secretion of pro-angiogenic IL-8 and MMP9 in vitro. Fibroblasts exposed to viable and IA-PBMC derived SN caused RNA increment of IL-8 and MMP9. AMI rats that were infused with IA-PBMC cell suspension evidenced enhanced homing of endothelial progenitor cells within 72 h as compared to control (medium alone, viable-PBMC). Echocardiography showed a significant reduction in infarction size and improvement in post AMI remodelling as evidenced by an attenuated loss of ejection fraction.

CONCLUSION

These data indicate that infusion of IA-PBMC cell suspension in experimental AMI circumvented inflammation, caused preferential homing of regenerative EPC and replaced infarcted myocardium.

T cell senescence and contraction of T cell repertoire diversity in patients with chronic obstructive pulmonary disease

Pathogenetic mechanisms leading to chronic obstructive pulmonary disease (COPD) remain poorly understood. Because clonogenic T cells (CD4(+)CD28(null)) were shown to be increased in autoimmune diseases we hypothesized that CD4(+)CD28(null) T cells play a role in COPD. Here we describe that enhanced presence of CD4(+)CD28(null) cells is associated with impaired lung function. Sixty-four patients and controls were included. T cell phenotype was analysed using flow cytometry. Enzyme-linked immunosorbent assays were utilized to determine cytokines. Statistical evaluations were performed using non-parametric group comparisons and correlations. A logistic regression model was used to determine predictive values of CD4(+)CD28(null) in the diagnosis of COPD. Populations of CD4(+) T cells lacking surface co-stimulatory CD28 were enlarged significantly in evaluated patients when compared with controls. Natural killer (NK)-like T cell receptors (CD94, 158) and intracellular perforin, granzyme B were increased in CD4(+)CD28(null) cells. Cytokine production after triggering of peripheral blood mononuclear cells (PBMCs) was elevated in patients at early disease stages. Receiver operating characteristic curve plotting revealed that presence of CD4(+)CD28(null) T cells has a diagnostic value. These CD4(+)CD28(null) T cells show increased expression of NK-like T cell receptors (CD94, 158) and intracellular perforin and granzyme B. Furthermore, triggering of PBMCs obtained from patients with mild COPD led to increased interferon-gamma and tumour necrosis factor-alpha production in vitro compared with controls. Our finding of increased CD4(+)CD28(null) T cells in COPD indicates that chronic antigen exposure, e.g. through contents of smoke, leads to loss of CD28 and up-regulation of NK cell receptors expression on T cells in susceptible patients.

Secretion of soluble ST2 - possible explanation for systemic immunosuppression after heart surgery

BACKGROUND

Cardiopulmonary bypass is known to affect cytokine release leading to a generalized endogenous immune reaction similar to that described in sepsis, without having been explored in great detail. Therefore we evaluated the anti- and pro-inflammatory cytokine responses after heart surgery.

METHODS

16 patients who underwent coronary artery bypass graft (CABG) surgery with extracorporeal circulation were included. ST2, IL-4 and IL-10 served as markers for TH2 cytokine response; IL-6, IL-8 and IFN-gamma as TH1 markers. Furthermore, total immunoglobulin subtype analysis (IgM, IgG, IgE) was performed.

RESULTS

Serum levels of soluble ST2 started to climb at 60 minutes (from 38 +/- 14 preoperatively to 1 480 +/- 890 pg/ml) and peaked 24 hours after surgery (13 360 +/- 2 840 pg/ml, P < 0.001). IL-10 reached a maximum at 60 minutes and returned to baseline levels 24 hours later. IL-6 and IL-8 levels peaked 60 minutes after surgery. IL-4 and IFN-gamma did not change. Only IgM showed a significant peak on day eight ( P < 0.001).

CONCLUSION

Our results demonstrate that CABG surgery induces a massive long-lasting secretion of ST2, a protein related to immune suppression.

Myocardial lipofuscin-laden lysosomes contain the apoptosis marker caspase-cleaved cytokeratin-18

BACKGROUND

Acute coronary syndrome is related to increased circulatory concentration of soluble apoptosis specific caspase-cleaved cytokeratin-18 (ccCK-18). Potential cardiac sources of this intermediate filament derivative have not been investigated to date.

MATERIALS AND METHODS

Paraffin embedded tissue of normal myocardium, and chronically damaged samples of ischaemic, congestive and hypertrophic cardiomyopathy were analysed by histology and by CK-8, CK-18, ccCK-18 immunohistochemistry (each group, n = 15). Antibody specificity of the ccCK-18 antibody M30 was checked by immunoblotting on lysed myocardium and enriched myocardial lysosomes.

RESULTS

ccCK-18 and CK-18 but not CK-8 were present in all forms of cardiomyopathy, most prominently in ischaemic cardiomyopathy while only traces were detectable immunohistochemically in normal myocardium. Weak CK-18 and strong ccCK-18 staining co-localized to lysosomes with cardiac age pigment lipofuscin. Weak staining of CK-18 was detected in the cytoplasm of coronary endothelia.

CONCLUSION

Our study reveals that cardiac lipofuscin-laden lysosomes contain ccCK-18, a marker of apoptosis and its precursor CK-18. This ccCK-18 pool might contribute to increased systemic levels of ccCK-18 in acute coronary syndrome thus monitoring myocardial damage.

Hepatic progenitor cells from adult human livers for cell transplantation

OBJECTIVE

Liver regeneration is mainly based on cellular self-renewal including progenitor cells. Efforts have been made to harness this potential for cell transplantation, but shortage of hepatocytes and premature differentiated progenitor cells from extra-hepatic organs are limiting factors. Histological studies implied that resident cells in adult liver can proliferate, have bipotential character and may be a suitable source for cell transplantation.

METHODS

Particular cell populations were isolated after adequate tissue dissociation. Single cell suspensions were purified by Thy-1 positivity selection, characterised in vitro and transplanted in immunodeficient Pfp/Rag2 mice.

RESULTS

Thy-1(+) cells that are mainly found in the portal tract and the surrounding parenchyma, were isolated from surgical liver tissue with high yields from specimens with histological signs of regeneration. Thy-1(+) cell populations were positive for progenitor (CD34, c-kit, CK14, M2PK, OV6), biliary (CK19) and hepatic (HepPar1) markers revealing their progenitor as well as hepatic and biliary nature. The potential of Thy-1(+) cells for differentiation in vitro was demonstrated by increased mRNA and protein expression for hepatic (CK18, HepPar1) and biliary (CK7) markers during culture while progenitor markers CK14, chromogranin A and nestin were reduced. After transplantation of Thy-1(+) cells into livers of immunodeficient mice, engraftment was predominantly seen in the periportal portion of the liver lobule. Analysis of in situ material revealed that transplanted cells express human hepatic markers HepPar1 and albumin, indicating functional engraftment.

CONCLUSION

Bipotential progenitor cells from human adult livers can be isolated using Thy-1 and might be a potential candidate for cell treatment in liver diseases.

Adiponectin and its receptors in rodent models of fatty liver disease and liver cirrhosis

AIM: To determine circulating and hepatic adiponectin in rodents with fatty liver disease or liver cirrhosis and investigate expression of the adiponectin receptors AdipoR1 on the mRNA and protein level and AdipoR2 on the mRNA level.

METHODS: Fat fed rats were used as a model for fatty liver disease and bile duct ligation in mice to investigate cirrhotic liver. Expression of AdipoR1 and AdipoR2 mRNA was determined by real time RT-PCR. AdipoR1 protein was analysed by immunoblot. Adiponectin was measured by ELISA.

RESULTS: Systemic adiponectin is reduced in fat-fed rats but is elevated in mice after bile duct ligation (BDL). Hepatic adiponectin protein is lower in steatotic liver but not in the liver of BDL-mice when compared to controls. Adiponectin mRNA was not detected in human liver samples or primary human hepatocytes nor in rat liver but recombinant adiponectin is taken up by isolated hepatocytes in-vitro. AdipoR1 mRNA and AdipoR1 protein levels are similar in the liver tissue of control and fat fed animals whereas AdipoR2 mRNA is induced. AdipoR2 mRNA and AdipoR1 mRNA and protein is suppressed in the liver of BDL-mice.

CONCLUSION: Our studies show reduced circulating adiponectin in a rat model of fatty liver disease whereas circulating adiponectin is elevated in a mouse model of cirrhosis and similar findings have been described in humans. Diminished hepatic expression of adiponectin receptors was only found in liver cirrhosis.

Expression of augmenter of liver regeneration (ALR) in human liver cirrhosis and carcinoma

AIMS

To determine the expression of a protein termed augmenter of liver regeneration (ALR), recently found to have a specific and beneficial effect on the process of liver regeneration in normal and diseased human liver.

METHODS AND RESULTS

ALR expression in normal and cirrhotic human livers with various underlying diseases as well as in tissue samples of hepatocellular carcinoma (HCC) and cholangiocellular carcinoma (CCC) was analysed by immunohistochemistry and quantitative reverse transciptase-polymerase chain reaction (RT-PCR). Expression analysis of ALR in total liver protein extracts by Western blotting showed mainly dimeric ALR protein. Immunohistochemically, cytosolic and perinuclear immunosignals were found in hepatocytes and cholangiocytes in normal, cirrhotic or cancerous liver tissue and only weak signals in some endothelial cells in normal livers. Quantitative mRNA analysis revealed significantly increased ALR expression in cirrhosis compared with normal liver tissue. In HCC and CCC ALR mRNA expression was also significantly enhanced compared with normal liver tissue, but expression levels did not differ from the matching non-neoplastic tissue in the same patient.

CONCLUSIONS

The findings suggest an important role for ALR in hepatocellular regeneration in liver cirrhosis as well as in hepatocarcinogenesis and therefore its potential value in the clinical diagnosis of hepatic cirrhosis and cancer.