Loss of ceramide synthase 5 inhibits the development of experimentally induced aortic valve stenosis

AIM

Inflammation and calcification are hallmarks in the development of aortic valve stenosis (AVS). Ceramides mediate inflammation and calcification in the vascular tissue. The highly abundant d18:1,16:0 ceramide (C16) has been linked to increased cardiovascular mortality and obesity. In this study, we investigate the role of ceramide synthase 5 (CerS5), a critical enzyme for C16 ceramide synthesis, in the development of AVS, particularly in conjunction with a high-fat/high-cholesterol diet (Western diet, WD).

METHODS

We used wild-type (WT) and CerS5-/- mice on WD or normal chow in a wire injury model. We measured the peak velocity to determine AVS development and performed histological analysis of the aortic valve area, immune cell infiltration (CD68 staining), and calcification (von Kossa). In vitro experiments involved measuring the calcification of human aortic valvular interstitial cells (VICs) and evaluating cytokine release from THP-1 cells, a human leukemia monocytic-like cell line, following CerS5 knockdown.

RESULTS

CerS5-/- mice showed a reduced peak velocity compared to WT only in the experiment with WD. Likewise, we observed reduced immune cell infiltration and calcification in the aortic valve of CerS5-/- mice, but only on WD. In vitro, calcification was reduced after knockdown of CerS5 in VICs, while THP-1 cells exhibited a decreased inflammatory response following CerS5 knockdown.

CONCLUSION

We conclude that CerS5 is an important mediator for the development of AVS in mice on WD and regulates critical pathophysiological hallmarks of AVS formation. CerS5 is therefore an interesting target for pharmacological therapy and merits further investigation.

Analysis of circulating ceramides and hexosylceramides in patients with coronary artery disease and type II diabetes mellitus

BACKGROUND

Cardiovascular disease (CVD) remains the leading cause of death worldwide. The main driving force behind this association is coronary artery disease (CAD), the manifestation of atherosclerosis in the coronary circulation. Cornerstones in the development of CAD are pathologies in lipid metabolism. In recent years, ongoing research has identified ceramides, a subclass of sphingolipids to be mediators of CVD. The aim of this study is to investigate the influence of type II diabetes mellitus (DM) on circulating ceramides and hexosylceramides (HexCers) in CAD patients.

METHODS

24 patients aged 40-90 years with CAD confirmed by angiography were included into a pilot study. Patients with DM were identified by analysis of discharge letters or other medical documents available at the study center. During coronary angiography, arterial blood samples were collected and quantification of sphingolipids in patient serum was performed by mass spectrometry.

RESULTS

Statistical analysis showed nine significantly different HexCers in CAD patients with DM compared to patients without DM. Among the nine significantly regulated HexCers, we identified seven d18:1 HexCers. This group contributes to the fourth most abundant subgroup of total ceramides and HexCers in this dataset. HexCer-d18:1-23:1(2-OH) showed the strongest downregulation in the patient group with DM.

CONCLUSION

This study suggests that levels of circulating HexCers are downregulated in patients with CAD and concomitant DM compared to patients without DM. Further research is needed to investigate the underlying mechanisms and the suitability of HexCers as possible mediators and/or prognostic markers in CAD.

Human and porcine aortic valve endothelial and interstitial cell isolation and characterization

Background

Calcific aortic valve stenosis (AVS) is defined by pathological changes in the aortic valve (AV) and their predominant cell types: valvular interstitial (VICs) and endothelial cells (VECs). Understanding the cellular and molecular mechanisms of this disease is a prerequisite to identify potential pharmacological treatment strategies. In this study, we present a unique aortic valve cell isolation technique to acquire specific human and porcine cell populations and compared VICs and VECs of these species with each other for the first time.

Methods

AV cells were isolated from tissue obtained from human patients undergoing surgical aortic valve replacement (SAVR) or from porcine hearts. Functional analysis and in vitro experiments revealed that endothelial-to-mesenchymal transition (EndMT) can be induced in hVECs, leading to a significant increase in mesenchymal markers. In vitro calcification experiments of VICs demonstrated pronounced expression of calcification markers and visible calcific deposits in Alizarin Red staining in both species after incubation with pro-calcific media.

Results

Cells isolated from patient-derived AVs showed mesenchymal and endothelial-specific gene signatures (VIC and VEC, respectively). For instance, von Willebrand factor (vWF) and platelet endothelial adhesion molecule-1 (PECAM1) were upregulated in VECs, while the myofibroblastic markers alpha-smooth muscle actin (α-SMA) and vimentin (VIM) were downregulated in VECs compared to VICs. Analysis of cell function by migration revealed that VECs are more migratory than VICs. Induction of EndMT in vitro in VECs displayed increased expression of EndMT markers and decreased expression of endothelial markers, confirming their mesenchymal transdifferentiation ability. In vitro calcification of VICs revealed upregulation of alkaline phosphatase (ALPL), a hallmark of calcification. In addition, other calcification-related genes such as osteocalcin (BGLAP) and runt-related factor 2 (RUNX2) were upregulated. Alizarin red staining of calcified cells provided a further layer of confirmation that the isolated cells were VICs with osteoblastic differentiation capacity.

Conclusion

This study aims to take a first step towards standardizing a reproducible isolation technique for specific human and porcine VEC and VIC populations. A comparison of human and porcine aortic valve cells demonstrated that porcine cells may serve as an alternative cellular model system in settings where human tissue is difficult to obtain.

Methods for the identification and characterization of extracellular vesicles in cardiovascular studies: from exosomes to microvesicles

Extracellular vesicles (EVs) are nanosized vesicles with a lipid bilayer that are released from cells of the cardiovascular system, and are considered important mediators of intercellular and extracellular communications. Two types of EVs of particular interest are exosomes and microvesicles, which have been identified in all tissue and body fluids and carry a variety of molecules including RNAs, proteins, and lipids. EVs have potential for use in the diagnosis and prognosis of cardiovascular diseases and as new therapeutic agents, particularly in the setting of myocardial infarction and heart failure. Despite their promise, technical challenges related to their small size make it challenging to accurately identify and characterize them, and to study EV-mediated processes. Here, we aim to provide the reader with an overview of the techniques and technologies available for the separation and characterization of EVs from different sources. Methods for determining the protein, RNA, and lipid content of EVs are discussed. The aim of this document is to provide guidance on critical methodological issues and highlight key points for consideration for the investigation of EVs in cardiovascular studies.

Toll-like receptor-3 contributes to the development of aortic valve stenosis

Aortic valve stenosis (AS) development is driven by distinct molecular and cellular mechanisms which include inflammatory pathways. Toll-like-receptor-3 (TLR3) is a lysosomal pattern-recognition receptor that binds double-stranded RNA and promotes pro-inflammatory cellular responses. In recent years, TLR3 has emerged as a major regulator of vascular inflammation. The exact role of TLR3 in the development of AS has not been investigated. Isolated human valvular interstitial cells (VICs) were stimulated with the TLR3-agonist polyIC and the resulting pro-inflammatory and pro-osteogenic response measured. Severe AS was induced in wildtype- and TLR3^-/- mice via mechanical injury of the aortic valve with a coronary springwire. TLR3 activation was achieved by polyIC injection every 24 h after wire injury, while TLR3 inhibition was realized using Compound 4a (C4a) every 48 h after surgery. Endothelial mesenchymal transition (EndoMT) of human valvular endothelial cells (VECs) was assessed after polyIC stimulation. Stimulation of human VICs with polyIC promoted a strong inflammatory and pro-osteogenic reaction. Similarly, injection of polyIC marginally increased AS development in mice after wire injury. AS induction was significantly decreased in TLR3^-/- mice, confirming the role of endogenous TLR3 ligands in AS pathology. Pharmacological inhibition of TLR3 with C4a not only prevented the upregulation of inflammatory cytokines and osteogenic markers in VICs, and EndoMT in VECs, but also significantly abolished the development of AS in vivo. Endogenous TLR3 activation significantly contributes to AS development in mice. Pharmacological inhibition of TLR3 with C4a prevented AS formation. Therefore, targeting TLR3 may be a viable treatment option.

Circulating MicroRNA-122-5p Is Associated With a Lack of Improvement in Left Ventricular Function After Transcatheter Aortic Valve Replacement and Regulates Viability of Cardiomyocytes Through Extracellular Vesicles

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is a well-established treatment option for high- and intermediate-risk patients with severe symptomatic aortic valve stenosis. A majority of patients exhibit improvements in left ventricular ejection fraction (LVEF) after TAVR in response to TAVR-associated afterload reduction. However, a specific role for circulating microRNAs (miRNAs) in the improvement of cardiac function for patients after TAVR has not yet been investigated. Here, we profiled the differential expression of miRNAs in circulating extracellular vesicles (EVs) in patients after TAVR and, in particular, the novel role of circulating miR-122-5p in cardiomyocytes.

METHODS

Circulating EV-associated miRNAs were investigated by use of an unbiased Taqman-based human miRNA array. Several EV miRNAs (miR-122-5p, miR-26a, miR-192, miR-483-5p, miR-720, miR-885-5p, and miR-1274) were significantly deregulated in patients with aortic valve stenosis at day 7 after TAVR compared with the preprocedural levels in patients without LVEF improvement. The higher levels of miR-122-5p were negatively correlated with LVEF improvement at both day 7 (r=-0.264 and P=0.015) and 6 months (r=-0.328 and P=0.0018) after TAVR.

RESULTS

Using of patient-derived samples and a murine aortic valve stenosis model, we observed that the expression of miR-122-5p correlates negatively with cardiac function, which is associated with LVEF. Mice with graded wire injury-induced aortic valve stenosis demonstrated a higher level of miR-122-5p, which was related to cardiomyocyte dysfunction. Murine ex vivo experiments revealed that miR-122-5p is highly enriched in endothelial cells compared with cardiomyocytes. Coculture experiments, copy-number analysis, and fluorescence microscopy with Cy3-labeled miR-122-5p demonstrated that miR-122-5p can be shuttled through large EVs from endothelial cells into cardiomyocytes. Gain- and loss-of-function experiments suggested that EV-mediated shuttling of miR-122-5p increases the level of miR-122-5p in recipient cardiomyocytes. Mechanistically, mass spectrometry, miRNA pulldown, electrophoretic mobility shift assay, and RNA immunoprecipitation experiments confirmed that miR-122-5p interacts with the RNA-binding protein hnRNPU (heterogeneous nuclear ribonucleoprotein U) in a sequence-specific manner to encapsulate miR-122-5p into large EVs. On shuttling, miR-122-5p reduces the expression of the antiapoptotic gene BCL2 by binding to its 3' untranslated region to inhibit its translation, thereby decreasing the viability of target cardiomyocytes.

CONCLUSIONS

Increased levels of circulating proapoptotic EV-incorporated miR-122-5p are associated with reduced LVEF after TAVR. EV shuttling of miR-122-5p regulates the viability and apoptosis of cardiomyocytes in a BCL2-dependent manner.

Loss of ceramide synthase 5 reduces the development of aortic valve stenosis in mice with high fat diet

Background

Ceramide synthase 5 (CerS5) is essential to maintain C:16 ceramide levels in mice. Ceramides contribute to inflammation and calcification, two hallmarks of aortic valve stenosis development. It is known, that loss of CerS5 function reduces diet-induced obesity.

Purpose

The aim of this study was to investigate the effect of ceramide synthase 5 and high-fat diet on the development of aortic valve stenosis with a mouse model.

Methods

Our experiment consists of four groups of mice: Wild type (WT) and CerS5 (−/−) mice, with normal and high fat diet. We induced the aortic valve stenosis development through a wire-injury. For this model, a coronary angiography wire is introduced into the left ventricle over the right carotid artery, followed by rotation on the aortic valve level to generate a defined injury. Development of aortic valve stenosis was determined by measuring the peak velocity 14, 28 and 42 days after the wire-injury. With histological analysis of the aortic valve, we measured macrophage infiltration with CD68 immunostaining and calcification using von Kossa staining. For statistical analysis ANOVA and Turkeys multiple comparisons were performed.

Results

Histological analysis of the aortic valve revealed, that in CerS5 (−/−) mice with high fat diet (HFD) immune cell infiltration is reduced, while there is no difference between CerS5 (−/−) mice and wild type, when fed with normal diet (A). Also calcification showed a trend towards a reduction in CerS5 mice with high fat diet, but was not statistically significant (B). Echocardiography could detect a reduced peak velocity of CerS5 mice with high fat diet, in comparison to the other groups, four and six weeks after wire injury (C).

Conclusion

Our experiments indicate that loss of CerS5 function reduces the development of aortic valve stenosis in mice with high fat diet, by decreasing immune cell infiltration and calcification. Interestingly, in the groups with normal chow, loss of CerS5 function had no effect. In addition, high-fat diet alone had no negative effect in our mouse model. Based on our results it can be assumed that upon high fat diet CerS5 mediates for pro-inflammatory effects in the aortic valve, which are absent on normal diet.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Ernst & Berta Grimmke Foundation (13/19)

Characterization of the mitochondrial unfolded protein response in human coronary artery endothelial cells

Background

The unfolded protein response of the endoplasmic reticulum (UPRER) is highly activated in cardiovascular diseases and aims to restore homeostasis by improving protein folding. An analogue cytoprotective mitochondrial unfolded protein response (UPRMito) regulated by an orthologue of the activating transcription factor 5 (ATF5) was described in model organism c. elegans. However, in humans it is not clear if there is a distinct UPRMito, and if there is an activation of an UPRMito during stress induced by cardiovascular diseases. The endothelium is subjected to high levels of mitochondrial stress, e.g. in atherosclerosis.

Purpose

To provide a systematic characterization of the UPRMito in human coronary artery endothelial cells (HCAEC).

Methods and results

HCAEC were treated with Nicotinamide Riboside (NR), a NAD+ precursor that activates UPRMito without inducing cellular stress. NR treatment did not induce toxicity and improved cell viability at a concentration of 100μM NR. Quantitative PCR confirmed a dose-dependent upregulation of UPRMito markers. Additionally, we measured expression of ATF4, which is discussed to regulate an integrated stress response in mammals by activating both the UPRMito and UPRER. ATF4 upregulation upon NR treatment was more pronounced than ATF5 upregulation. Analysis of GTEX-Data showed that ATF5 is almost exclusively expressed in liver tissue, while ATF4 shows ubiquitous expression. Among 54 tissues, aortic tissue and coronary arterial tissue are among the five tissues with the highest ATF4 expression.

Analysis of RNA-seq-data of human carotid atherosclerosis revealed that the two transcription factors are differentially regulated. ATF4 is downregulated in unstable plaque, while ATF5 is upregulated. Moreover, ATF4 is in both conditions highly more abundant than ATF5. Accordingly, endothelial cells incubated under atherosclerotic conditions (oxLDL + high glucose) exhibited a ATF4 down- and ATF5 upregulation. Genes previously described to be involved in the UPRMito exhibited a similar expression pattern as ATF4.

To further elucidate these findings, we will perform transcriptomic analyses of HCAEC treated with atherosclerotic stimuli (IL-1β, oxLDL), UPRER inductors (Thapsigargin, Tunicamycin) and stressors of mitochondrial proteostasis (Oligomycin, MitoBloCK-6), to analyze, if ATF5- or ATF4-related pathways are dysregulated. Specific inhibitors and UPRMito activators will be used to investigate the significance of ATF4 and ATF5 on endothelial cell function (proliferation, migration, apoptosis, monocyte adhesion).

Conclusion

The UPRMito is dysregulated during the pathogenesis of atherosclerosis in HCAEC. Further findings are required to elucidate, if the UPRMito is activated separately and specifically by ATF5 or as part of an integrated cellular stress response by ATF4. A deeper understanding of these stress responses is crucial for the identification of novel therapeutic targets in atherosclerosis.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): University hospital Bonn

Serum levels of the endoplasmic-reticulum-stress chaperone GRP78 identify patients with coronary artery disease and predict mortality

Background

Endoplasmic-reticulum-stress (ER Stress) and associated chaperones like the main ER-Stress moderator GRP78 (glucose-regulated-protein, 78kDa) are involved in the pathogenesis of coronary artery disease (CAD). In addition to their intracellular localization and effects, secretion and extracellular properties of chaperones, including GRP78, were recently described. However, a diagnostic or prognostic relevance of serum ER-chaperones in patients with CAD has not been established yet.

Purpose

To investigate the significance of serum GRP78 in patients undergoing coronary angiography for suspected CAD.

Methods

Serum concentration of GRP78 was measured by ELISA in 789 patients with indication for coronary angiography (both ACS and CCS). CAD was defined as >50% stenosis in any major coronary artery. Clinical endpoint was one-year all-cause mortality.

Results

Mean age was 70.8±11.9 years and 65% of patients were male. 192 (24%) patients presented with acute coronary syndrome (ACS). CAD was found in 72.4% of patients. Mean GRP78 serum concentration was 2492 ng/ml. Increased levels of GRP78 (> median) were associated with diabetes (29.9% vs. 23.1%, p=0.03), a higher BMI (28.9±7.1 kg/m2 vs. 27.0±6.0 kg/m2, p<0.0001) and chronic kidney disease (CKD: 23.3% vs. 17.1%, p=0.03). There was no difference regarding age or sex.

GRP78 levels were increased in patients with CAD when compared to patients without CAD (2640 ng/ml [95% CI: 2415–2864] vs. 2178 ng/ml [95% CI: 1893–2463], p=0.013, Fig A). Interestingly, GRP78 levels were lower in patients with ACS than in patients with CCS (2284 ng/ml [95% CI: 1944–2642] vs. 2822 [95% CI: 2531–3113], p=0.018, Fig B). To further elucidate these findings, we analyzed available proteomics of patients with hypertrophic cardiomyopathy undergoing septal ablation as a model for a planned myocardial infarction (PMI)1. Coronary sinus blood samples drawn 10 and 60 min after PMI showed a downregulation of GRP78 levels compared to baseline.

Finally, we assessed prognostic relevance of GRP78 in patients with CAD. Increased GRP78 levels were associated with lower one-year mortality (5.3% vs. 10.6% vs. p=0.016). Increased GRP78 levels were associated with reduced one-year mortality in both continuous (HR: 0.48 [95% CI: 0.25–0.92]) and categorial analyses stratified by median GRP78. After adjusting for age, sex, BMI, diabetes, CKD and ACS, GRP78 remained an independent predictor of one-year mortality (HR: 0.51 [0.26–0.96], p=0.039).

Conclusion

GRP78 serum levels are generally elevated in patients with CAD but downregulated during ACS. Reduced levels are associated with increased one-year mortality. These results support previous findings that GRP78 secretion is a protective mechanism in cardiovascular diseases. Further mechanistic studies are warranted to foster our understanding of the effects of extracellular GRP78 and to aid in the identification of modifying therapeutic targets.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): University hospital Bonn

The endoplasmic reticulum (ER) chaperone GRP78 is secreted during ER Stress and alleviates endothelial cell inflammation

Introduction

Glucose-Regulated Protein 78kD (GRP78) is a chaperone and the main regulator of the ER-stress response. Upon ER Stress, GRP78 activates the unfolded protein response (UPR), which aims to clear unfolded proteins and restore ER homeostasis. A prolonged activation of the UPR triggers inflammation, thus contributing to the progression of cardiovascular diseases. Recently, extracellular secretion of GRP78 was described. However, the pathophysiological relevance of secreted GRP78 in atherosclerosis and endothelial cell inflammation remains to be elucidated.

Aim

Aim of this study is to investigate the role of GRP78 secretion in endothelial cells.

Methods and results

First, we sought to investigate if vascular cells secrete GRP78 during ER Stress. Human coronary artery endothelial cells (HCAEC) were treated with the ER stress inductor tunicamycin for up to 48h. After ER Stress induction, Western Blot and ELISA experiments detected an increased intracellular GRP78 expression. Intriguingly, prolonged ER Stress also promoted extracellular secretion of GRP78. Proteomic analysis confirmed that after ER-Stress induction, GRP78 is one of the most highly upregulated extracellular proteins (2.43-fold). Co-incubation with Brefeldin A, an inhibitor of ER-Golgi protein transport, abolished extracellular secretion (Fig.1). Hence, ER-Stress-induced GRP78 secretion is an actively regulated process.

Next, the effect of GRP78 containing conditioned medium (CM) on HCAEC was analyzed. Treatment with GRP78 containing CM decreased GRP78 mRNA expression in target cells (0.35-fold vs. control [+BFA], p<0.0001). Furthermore, it increased viability (93.0% vs. 79.6%, p=0.017) and decreased formation of reactive oxygen species (0.78-fold). Moreover, expression of markers of vascular inflammation and ER Stress (e.g., NF-κB and CHOP) was decreased when compared to control CM with additional BFA treatment.

However, ER Stress induced by tunicamycin exhibits deleterious effects on donor cells and is therefore not feasible for in vivo usage. Thus, we utilized Bip protein inducer x (Bix), a recently described small-molecule activator of GRP78. Treatment with Bix also promoted expression of GRP78 and general UPR activation (e.g., ATF4, XBP1). Moreover, in contrast to tunicamycin, Bix treatment did not impair viability of HCAEC.

After treatment with Bix-induced CM, apoptosis (0.77-fold vs. 1.64-fold, p<0.0001) and expression of markers of vascular inflammation (e.g., Il-6) were significantly decreased compared to control CM. Furthermore, presence of GRP78 was able to promote proliferation and viability.

Conclusion

Endothelial ER Stress promotes GRP78 secretion. Presence of GRP78 in conditioned medium ameliorates subsequent ER Stress and endothelial inflammation, which play a critical role in atherogenesis. Modification of GRP78 secretion by Bix might be a feasible and innovative therapeutic option for vascular inflammation and endothelial regeneration.

Funding Acknowledgement

Type of funding sources: None.

OAT3A1/NKD2 mediates increased calcification of aortic valvular interstitial cells under in vitro conditions of uremia

Background

Chronic kidney disease is closely associated with cardiovascular disease which contributes to a high mortality and morbidity in these patients. Calcific aortic valve stenosis is the most common valve disease among adults. CKD leads to a higher incidence of AS and is associated with impaired clinical outcomes after valve replacement. CKD leads to retention of uremic toxins, such as indoxyl sulfate (IS), which is known to induce inflammatory and pro-calcific processes. The influence of IS on AS pathophysiology is currently not known.

Methods and results

Human aortic valvular interstitial cells (VICs) were stimulated by 4 different conditions: Control medium (CM), CM and IS in a concentration of 50 mmol/l, pro-calcifying medium (PCM) which was produced by adding NaH2PO4 and L-ascorbic acid to CM and PCM+IS. After 7 days of incubation, VICs were fixed in formalin and calcification was evaluated through staining with alizarin red solution (B). Staining was quantified by photometric measurements at 540 nm. We observed a significantly higher degree of VIC calcification under the influence PCM+IS compared to PCM alone (C). VICs were stimulated for 7 days and next-generation RNA Sequencing (RNA Seq) was performed. Analysis of RNA Seq dataset identified naked cuticle homologue 2 (NKD2) to be strongly regulated by IS. This effect was confirmed by qPCR using VICs from a total of three different human donors and immunoblot analysis (D, E). We observed a more pronounced upregulation of NKD2 gene expression under PCM+IS vs. PCM alone (p<0.0001) (D). To investigate the influence of NKD2 on VIC calcification genetic knockdown of NKD2 was performed by transfecting VICs with NKD2 siRNA compared and scrambled siRNA as negative control (nc siRNA) (F). After 21 days of stimulation and subsequent alizarin staining, we observed a significant decrease in VIC calcification under NKD2 knockdown compared to negative control under PCM+IS conditions (G, H). To identify upstream mechanisms that lead to NKD2 upregulation by IS we investigated the influence of organic anion transporters (OAT) which are responsible for cellular uptake of IS. Probenecid, known as a potent inhibitor of OATs showed a dose dependent suppression of NKD2 upregulation under PCM+IS (I). Systematic analysis of RNA Seq data regarding SLCO genes coding for OAT and OAT-peptides revealed that only SLCO3A1, coding for OAT3A1 is highly abundant in VICs (J). SLCO3A1 knockdown showed a significant decrease of NKD2 expression after stimulation with PCM+IS for 7 days compared to negative control (K).

Conclusion

Our findings show that in vitro conditions of uremia increase calcification of aortic VICs. NKD2 expression is regulated by PCM and IS, and PCM+IS treated cells show the strongest upregulation of NKD2. Genetic knockdown of NKD2 attenuates VIC calcification suggesting a role of NKD2 in this process. Further, our findings suggest that OAT3A1 is involved in IS mediated regulation of NKD2 expression.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Medical faculty of the University of Bonn, German Cardiac Society (DGK), German Research Foundation (DFG), TRR259

Low blood levels of the lncRNA MRPL20-AS1 are associated with severe obstructive sleep apnea

Introduction

Obstructive sleep apnea syndrome (OSAS) is the most common sleep disorder and it is associated with arterial hypertension, heart failure, coronary artery disease as well as atrial fibrillation. The underlying pathomechanisms for this association are only incompletely understood. In recent years long non-coding RNAs (lncRNA) have been shown to be involved in various cardiovascular pathologies. The aim of this study is to identify lncRNAs which are associated with OSAS in order to provide potential therapeutic targets.

Methods and results

In order to tackle this issue, we included 23 Patients with a suspected OSAS in a pilot study and sampled blood on the evening before and on the morning after polysomnographic analysis. Citrate was used to inhibit clotting of the blood and cellular components were removed by centrifugation, before the plasma was stored at −80°C. One patient had no sign of OSAS as indicated by an Apnea/Hypopnea-Index (AHI) <5 per hour and was therefore excluded. The remaining 22 patients had a mean age of 44.45 years and a mean AHI of 28.38 per hour. Three of the patients were female and nineteen were male. In four of those patients with high AHI levels, we performed a RNA sequencing analysis from the citrate plasma and found MRPL20-AS1 to be the most significantly regulated lncRNA after the night of polysomnographic analysis (A). Low coding potential of MRPL20-AS1 was confirmed in silico via the Coding-Potential Assessment Tool (http://lilab.research.bcm.edu/) resulting in a coding probability of 0.06148. Then MRPL20-AS1 levels were measured via qPCR in the remaining patients. From 19 patients, we obtained evaluable results. We found that MRPL20-AS1 blood levels had the tendency to be lower after the night of polysomnographic assessment (B). Interestingly MRPL20-AS1 levels were inversely correlated with the AHI of the OSAS patients (C). This indicates that severe OSAS was associated with low levels of MRPL20-AS1 in our cohort (D). In order to further investigate these results in vitro, we subjected human coronary artery endothelial cells (HCAECs) to hypoxia (1% and 5% O2) for 24 h. We found that hypoxia leads to a significant downregulation of MRPL20-AS1 in HCAECs (E).

Conclusion

MRPL20-AS1 blood levels are lower in patients with severe OSAS after nocturnal hypoxia. In endothelial cells MRPL20-AS1 is downregulated after hypoxia. MRPL20-AS1 can therefore be useful to identify patients suffering from severe OSAS. Further investigations are needed to elucidate the biological function of MRPL20-AS1 in the context of OSAS and to investigate MRPL20-AS1 as a potential therapeutic target to counteract cardiovascular effects of OSAS

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Unviversity of BonnUniversity of Cologne

ER-stress-induced secretion of circulating glucose-regulated protein 78kDa (GRP78) ameliorates pulmonary artery smooth muscle cell remodelling

Pulmonary arterial hypertension (PAH) is driven by vascular remodelling due to inflammation and cellular stress, including endoplasmic reticulum stress (ER stress). The main ER-stress chaperone, glucose-regulated protein 78 kDa (GRP78), is known to have protective effects in inflammatory diseases through extracellular signalling. The aim of this study is to investigate its significance in PAH. Human pulmonary arterial smooth muscle cells (PASMC) were stimulated with compounds that induce ER stress, after which the secretion of GRP78 into the cell medium was analysed by western blot. We found that when ER stress was induced in PASMC, there was also a time-dependent secretion of GRP78. Next, naïve PASMC were treated with conditioned medium (CM) from the ER-stressed donor PASMC. Incubation with CM from ER-stressed PASMC reduced the viability, oxidative stress, and expression of inflammatory and ER-stress markers in target cells. These effects were abrogated when the donor cells were co-treated with Brefeldin A to inhibit active secretion of GRP78. Direct treatment of PASMC with recombinant GRP78 modulated the expression of key inflammatory markers. Additionally, we measured GRP78 plasma levels in 19 PAH patients (Nice Group I) and correlated the levels to risk stratification according to ESC guidelines. Here, elevated plasma levels of GRP78 were associated with a favourable risk stratification. In conclusion, GRP78 is secreted by PASMC under ER stress and exhibits protective effects from the hallmarks of PAH in vitro. Circulating GRP78 may serve as biomarker for risk adjudication of patients with PAH. Proposed mechanism of ER-stress-induced GRP78 secretion by PASMC. Extracellular GRP78 can be measured as a circulating biomarker and is correlated with favourable clinical characteristics. Conditioned medium from ER-stressed PASMC reduces extensive viability, ROS formation, inflammation, and ER stress in target cells. These effects can be abolished by blocking protein secretion in donor cells by using Brefeldin A.

Ceramide Metabolism in Cardiovascular Disease: A Network With High Therapeutic Potential

Growing evidence suggests that ceramides play an important role in the development of atherosclerotic and valvular heart disease. Ceramides are biologically active sphingolipids that are produced by a complex network of enzymes. Lowering cellular and tissue levels of ceramide by inhibiting the ceramide-producing enzymes counteracts atherosclerotic and valvular heart disease development in animal models. In vascular tissues, ceramides are produced in response to hyperglycemia and TNF (tumor necrosis factor)-α signaling and are involved in NO-signaling and inflammation. In humans, elevated blood ceramide levels are associated with cardiovascular events. Furthermore, important cardiovascular risk factors, such as obesity and diabetes, have been linked to ceramide accumulation. This review summarizes the basic mechanisms of how ceramides drive cardiovascular disease locally and links these findings to the intriguing results of human studies on ceramides as biomarkers for cardiovascular events. Moreover, we discuss the current state of interventions to therapeutically influence vascular ceramide metabolism, both locally and systemically.

The lncRNA MRPL20-AS1 is associated with severe OSAS and downregulated upon hypoxic injury of endothelial cells

INTRODUCTION

Obstructive sleep apnea syndrome (OSAS) is the most common sleep disorder in humans. Although OSAS is clearly related to arterial hypertension, coronary artery disease, and heart failure, it remains unknown through which pathomechanisms OSAS influences cardiovascular health. Recent research has pinpointed long non-coding RNAs (lncRNA) as important molecular mediators of various cardiovascular pathologies. In this study, we have identified the lncRNA MRPL20-AS1 to be affected by OSAS in patients as well as by hypoxia in vitro.

METHODS AND RESULTS

A transcriptomic analysis was performed on peripheral blood from four patients with severe OSAS taken after one night of polygraphic assessment. We found that three lncRNAs were significantly dysregulated, of which MRPL20-AS1 was the most significant. In a larger cohort of 22 OSAS patients, MRPL20-AS1 was inversely correlated with the apnea-hypopnea index (AHI). This indicates that OSAS patients with higher AHI levels and therefore more severe OSAS had lower levels of MRPL20-AS1 in the blood. The results were recapitulated in vitro by subjecting endothelial cells to hypoxia. In these experiments, hypoxia led to a significant downregulation of MRPL20-AS1 in endothelial cells.

CONCLUSION

MRPL20-AS1 may serve as a useful tool to identify patients suffering from severe OSAS and further research should be done to evaluate the therapeutic potential of MRPL20-AS1 as a target to counteract the cardiovascular effects of OSAS.

3D-speckle-tracking echocardiography correlates with cardiovascular magnetic resonance imaging diagnosis of acute myocarditis – An observational study

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Regional changes in myocardial texture (as diagnosed by CMR) were significantly associated with regional impairment of circumferential, longitudinal, and radial strain, as well as regional 3D displacement and total 3D strain.

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3D and 2D global longitudinal strain (GLS) showed higher diagnostic performance than well-known parameters associated with myocarditis, such as LVEF and LVEDV in our patient collective.

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3D-speckle-tracking echocardiography offers a promising diagnostic tool in the diagnosis of myocarditis.

Background

The diagnostic importance of three-dimensional (3D) speckle-tracking strain-imaging echocardiography in patients with acute myocarditis remains unclear. The aim of this study was to test the diagnostic performance of 3D-speckle-tracking echocardiography compared to CMR (cardiovascular magnetic resonance imaging) for the diagnosis of acute myocarditis.

Methods and results

45 patients with clinically suspected myocarditis were enrolled in our study (29% female, mean age: 43.9 ± 16.3 years, peak troponin I level: 1.38 ± 3.51 ng/ml). 3D full-volume echocardiographic images were obtained and offline 2D as well as 3D speckle-tracking analysis of regional and global LV deformation was performed. All patients received CMR scans and myocarditis was diagnosed in 29 subjects based on original Lake-Louise criteria. The 16 patients, in whom myocarditis was excluded by CMR, served as controls. Regional changes in myocardial texture (diagnosed by CMR) were significantly associated with regional impairment of circumferential, longitudinal, and radial strain, as well as regional 3D displacement and total 3D strain. Interestingly, the 2D and 3D global longitudinal strain (GLS) showed higher diagnostic performance than well-known parameters associated with myocarditis, such as LVEF (as obtained by echocardiography and CMR) and LVEDV (as obtained by CMR).

Conclusions

In this study, we examined the use of 3D-speckle-tracking echocardiography in patients with acute myocarditis. Global longitudinal strain was significantly impaired in patients with acute myocarditis and correlated with CMR findings. Therefore, 3D echocardiography could become a useful diagnostic tool in the primary diagnosis of myocarditis.

O-283 Evidence based management of endometriosis – what has changed since 2013?

In 2005, under the auspices of ESHRE, a group of international experts evaluated the existing best evidence and published the first European guideline on the management of endometriosis. This highly successful project was the first guideline by ESHRE and was adopted by many counties as their national standard. A second, fully-updated edition was presented in 2013.

For the new ESHRE Endometriosis Guideline, published in February 2022, all available evidence for twelve chosen topics was gathered by a senior research specialist. Subgroups comprised of patient representatives and experts in healthcare, reproductive science and epidemiology evaluated the data according to GRADE criteria. Each subgroup wrote a chapter and formulated their recommendations which were then presented by a representative to the core group. There, a provisional document was generated and made available for stakeholder review. The resulting comments were taken into account and where relevant incorporated into the final guideline document for which approval was sought and gained from the ESHRE Executive Committee.

35 PICO (Patients, Interventions, Comparison, Outcome) and seven narrative questions were addressed resulting in 78 Research Recommendations were formulated. Where sufficient scientific evidence was lacking and the Guideline Development Group (GDG) was of the opinion that an important topic needed to be highlighted Good Clinical Practice Points where created based on experts’ experience.

During the process of reviewing the literature it became apparent that large knowledge gaps of the best clinical approach to endometriosis exist. As a result, 30 research recommendations were also produced.

One of the main differences to the 2013 version of the ESHRE guidelines is that laparoscopy is no longer the gold standard for endometriosis per se as there exist sufficient data to support the use of transvaginal ultrasound performed by an experienced operator or MRI can equally identify or rule out ovarian and most of deep endometriosis. However, it is recognised by the GDG that the required imaging standards are not ubiquitously available and for peritoneal disease both sensitivity and specificity using either imaging modalities are still poor. As opposed to the 2013 recommendation, the GDG does not anymore recommend an ultralong protocol for the women with rASRM stage III/IV endometriosis to improve IVF success rates. Furthermore, gonadotropin releasing hormone antagonists seem to be effective in the treatment of endometriosis-associate pain and, where available, could be considered as second-line treatment.

Other changes were specific chapters on endometriosis in adolescents and in menopausal women as the GDG strongly felt that these groups are concerningly underrepresented in clinical care and research. Finally, a chapter focussing on the association of endometriosis with certain forms of cancer namely subgroups of ovarian cancer, breast and thyroid cancer was added to give both patients and clinicians a better insight into the current evidence of this complex topic.

The GDG hope that the new ESHRE Endometriosis Guideline will improve the clinical management of a highly prevalent and heterogenous disease and that the freely-available patient-friendly version of the guideline empowers symptomatic and asymptomatic women to seek the best available advice, support and treatment.

Analysis of nocturnal, hypoxia-induced miRNAs in sleep apnea patients

Introduction

Obstructive sleep apnea syndrome (OSAS) is associated with an increased cardiovascular risk. The underlying mechanisms are largely unclear. MicroRNAs (miRNAs) are RNAs circulating in the blood that can be released into the bloodstream during hypoxia. In the present study, we investigate if OSAS-induced hypoxia results in a release of miRNAs that may mediate OSAS-associated cardiovascular damage.

Methods

Blood was sampled from 23 OSAS patients before and after a polygraphically monitored night. Total circulating RNA was isolated from the plasma and quantified using real-time qPCR. Using a Taqman miRNA array, the levels of 384 different miRNAs were compared between evening and morning after polysomnography. The most highly upregulated miRNA (miRNA-505) and four additionally upregulated miRNAs (miRNA-127, miRNA-133a, miRNA-145, and miRNA-181a) were then quantified in a bigger patient cohort individually.

Results

Apnea/Hypopnea-Index (AHI) was evaluated and averaged at 26 per hour on nocturnal polygraphy. In an initial miRNA array, a total of 4 miRNAs were significantly regulated. A significant increase of miRNA-145 was observed in the larger patient cohort. No significant changes in concentration were detected for miRNA-127, miRNA-133a, miRNA-181a, and miRNA-505 in this larger cohort.

Conclusion

OSAS results in the nocturnal release of miRNAs into the bloodstream. Our collected data may indicate a hypoxia-induced release of miRNAs into the bloodstream of OSAS-patients. In vitro experiments are needed to confirm the secretion of these miRNAs under hypoxia and evaluate the effect on the cardio vasculature.

Transverse aortic constriction-induced heart failure leads to increased levels of circulating microparticles

BACKGROUND

Circulating microparticles represent one type of signal transmission between cells. Previous studies revealed increased levels of circulating microparticles in patients with heart failure, while composition, temporal occurrence and biological effects are largely unknown.

METHODS

Circulating microparticles were quantified by flow cytometry in mice following TAC. Microparticles were characterized by NTA and immunoblotting for Flotillin-1. Microparticle content was investigated by microRNA analyses.

RESULTS

After TAC induction of heart failure could be demonstrated. Simultaneously we observed increased numbers of circulating microparticles in the first week after TAC with a rapid decline thereafter. The most relevant fraction of circulating EVs after TAC derived from lymphocytes containing has-miR-26a-5p and / -146b-5p known to be involved in inflammatory processes.

CONCLUSION

This work provides a previously unknown timely limited occurrence of circulating microparticles after new onset of heart failure which might have important influence on disease development and progression and thereby are of probable therapeutic relevance.

MicroRNA-mediated vascular intercellular communication is altered in chronic kidney disease

AIMS

Chronic kidney disease (CKD) is an independent risk factor for the development of coronary artery disease (CAD). For both, CKD and CAD, the intercellular transfer of microRNAs (miRs) through extracellular vesicles (EVs) is an important factor of disease development. Whether the combination of CAD and CKD affects endothelial function through cellular crosstalk of EV-incorporated miRs is still unknown.

METHODS AND RESULTS

Out of 172 screened CAD patients, 31 patients with CAD + CKD were identified and matched with 31 CAD patients without CKD. Additionally, 13 controls without CAD and CKD were included. Large EVs from CAD + CKD patients contained significantly lower levels of the vasculo-protective miR-130a-3p and miR-126-3p compared to CAD patients and controls. Flow cytometric analysis of plasma-derived EVs revealed significantly higher numbers of endothelial cell-derived EVs in CAD and CAD + CKD patients compared to controls. EVs from CAD + CKD patients impaired target human coronary artery endothelial cell (HCAEC) proliferation upon incubation in vitro. Consistent with the clinical data, treatment with the uraemia toxin indoxyl sulfate (IS)-reduced miR-130a-3p levels in HCAEC-derived EVs. EVs from IS-treated donor HCAECs-reduced proliferation and re-endothelialization in EV-recipient cells and induced an anti-angiogenic gene expression profile. In a mouse-experiment, intravenous treatment with EVs from IS-treated endothelial cells significantly impaired endothelial regeneration. On the molecular level, we found that IS leads to an up-regulation of the heterogenous nuclear ribonucleoprotein U (hnRNPU), which retains miR-130a-3p in the cell leading to reduced vesicular miR-130a-3p export and impaired EV-recipient cell proliferation.

CONCLUSION

Our findings suggest that EV-miR-mediated vascular intercellular communication is altered in patients with CAD and CKD, promoting CKD-induced endothelial dysfunction.

Propensity-score-matched comparison of safety, efficacy, and outcome of intravascular lithotripsy versus high-pressure PTCA in coronary calcified lesions

•

Calcified coronary lesions are frequently in patients with coronary artery disease.

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Intravascular lithotripsy was shown to be safe and effective for treating calcified lesions in coronary artery disease.

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Data of intravascular lithotripsy in comparison to standard techniques are lacking.

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Intravascular lithotripsy showed higher rate of procedural success without differences in rate of MACE after 12 months in comparison to high- pressure NC-Balloon PTCA.

Background

Data regarding safety, efficacy, and outcome of intravascular lithotripsy (IVL) in comparison to standard techniques are lacking. This study sought to compare IVL with non-compliant high-pressure balloon percutaneous coronary angioplasty (PTCA).

Methods and results

We performed a retrospective propensity-score-matched study to compare procedural success in 57 consecutive patients who received IVL-guided PCI in calcified coronary lesions with 171 matched patients who were treated with high-pressure PTCA with a non-compliant (NC)-balloon. The mean minimal lumen diameter (MLD) for the IVL group was 1.08 ± 0.51 mm, and the median percent diameter stenosis on quantitative angiography was 70.2% (interquartile range, 60.2–78.6%). MLD in the high-pressure dilatation group was 0.97 ± 0.43 mm, and the median percent diameter stenosis was 71.5% (interquartile range, 58.5–77.0%). IVL-guided PCI reduced median stenosis to 17.5% (interquartile range, 9.3–19.8%) with an acute gain of 0.93 ± 0.7 mm. High-pressure dilatation resulted in a final median stenosis of 19.3% (interquartile range, 13.33–28.5%). Procedural success was significantly higher (82.5% vs. 61.4%; p: 0.0035) in the IVL group. MACE through 12 months occurred in 10.5% of cases in the IVL group and in 11.1% of the high-pressure group (p = 0.22). Angiographic complications (coronary dissection, slow or no reflow, new coronary thrombus formation, abrupt vessel closure) were very low (0.2% vs. 0.12%).

Conclusion

IVL resulted in a significantly higher rate of procedural success compared to high- pressure NC-balloon dilatation in patients with calcified coronary lesions. The rate of MACE through 12 months was similar to the standard therapy.

Activation of neutral sphingomyelinase 2 through hyperglycemia contributes to endothelial apoptosis via vesicle-bound intercellular transfer of ceramides

Background

Pro-apoptotic and pro-inflammatory ceramides are crucially involved in atherosclerotic plaque development. Local cellular ceramide accumulation mediates endothelial apoptosis, especially in type 2 diabetes mellitus, which is a major cardiovascular risk factor. In recent years, large extracellular vesicles (lEVs) have been identified as an important means of intercellular communication and as regulators of cardiovascular health and disease. A potential role for lEVs as vehicles for ceramide transfer and inductors of diabetes-associated endothelial apoptosis has never been investigated.

Methods and Results

A mass-spectrometric analysis of human coronary artery endothelial cells (HCAECs) and their lEVs revealed C16 ceramide (d18:1–16:0) to be the most abundant ceramide in lEVs and to be significantly increased in lEVs after hyperglycemic injury to HCAECs. The increased packaging of ceramide into lEVs after hyperglycemic injury was shown to be dependent on neutral sphingomyelinase 2 (nSMase2), which was upregulated in glucose-treated HCAECs. lEVs from hyperglycemic HCAECs induced apoptosis in the recipient HCAECs compared to native lEVs from untreated HCAECs. Similarly, lEVs from hyperglycemic mice after streptozotocin injection induced higher rates of apoptosis in murine endothelial cells compared to lEVs from normoglycemic mice. To generate lEVs with high levels of C16 ceramide, ceramide was applied exogenously and shown to be effectively packaged into the lEVs, which then induced apoptosis in lEV-recipient HCAECs via activation of caspase 3. Intercellular transfer of ceramide through lEVs was confirmed by use of a fluorescently labeled ceramide analogue. Treatment of HCAECs with a pharmacological inhibitor of nSMases (GW4869) or siRNA-mediated downregulation of nSMase2 abrogated the glucose-mediated effect on apoptosis in lEV-recipient cells. In contrast, for small EVs (sEVs), hyperglycemic injury or GW4869 treatment had no effect on apoptosis induction in sEV-recipient cells.

Conclusion

lEVs mediate the induction of apoptosis in endothelial cells in response to hyperglycemic injury through intercellular transfer of ceramides.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00018-021-04049-5.

NcRNAs in Vascular and Valvular Intercellular Communication

Non-coding RNAs have been shown to be important biomarkers and mediators of many different disease entities, including cardiovascular (CV) diseases like atherosclerosis, aneurysms, and valvulopathies. Growing evidence suggests a central role of ncRNAs as regulators of different pathological pathways involved in endothelial dysfunction, cardiovascular inflammation, cell differentiation, and calcification. This review will discuss the role of protein-bound and extracellular vesicular-bound ncRNAs as biomarkers of vascular and valvular diseases, their role as intercellular communicators, and regulators of disease pathways and also highlights possible treatment strategies.

Circulating microRNA-122-5p correlates with improvement in left-ventricular function after transcatheter aortic valve replacement and regulates viability of cardiomyocytes via extracellular vesicles

 

Transcatheter aortic valve replacement (TAVR) is a well-established treatment option for high- and intermediate-risk patients with severe symptomatic aortic valve stenosis (AVS). However, a specific role for circulating microRNAs (miRNAs) in the improvement of cardiac function for patients after TAVR has not yet been investigated. Herein, we generally explored the differential expression of miRNAs in circulating extracellular vesicles (EV-miRNAs) in patients after TAVR and, in particular, the novel role of circulating miR-122-5p in cardiomyocytes.

Circulating EV-associated miRNAs were investigated by using an unbiased Taqman-based human miR array. Several EV-miRNAs (miR-122-5p, miR-26a, miR-192, miR-483-5p, miR-720, miR-885-5p, and miR-1274) were significantly deregulated in aortic stenosis patients at day seven after TAVR in comparison to the pre-procedural levels in patients without LVEF-improvement. The higher levels of miR-122 were negatively correlated with LVEF improvement at both day seven (r=−0.264 and p=0.015) and at six months (r=−0.328 and p=0.0018) after TAVR. At the three-year follow-up, patients with a higher level of miR-122-5p displayed significantly increased cardiovascular mortality (p=0.03). By utilization of patient-derived samples and a murine aortic-stenosis model, we observed that the expression of miR-122-5p correlates negatively with cardiac function, which is associated with LVEF. Graded wire-injury-induced aortic-valve-stenotic mice demonstrated a higher level of miR-122-5p, which was related to cardiomyocyte dysfunction. Murine ex vivo experiments revealed that miR-122-5p is highly enriched in endothelial cells in comparison to cardiomyocytes. Co-culture experiments with endothelial cells and cardiomyocytes, copy-number analysis, fluorescence microscopy with Cy3-labeled miR-122-5p demonstrated that miR-122-5p can be shuttled via large extracellular vesicles from endothelial cells into cardiomyocytes. Gain- and loss-of-function experiments suggested that EV-mediated shuttling of miR-122-5p increases the level of miR-122-5p in recipient cardiomyocytes and regulates viability of the cardiomyocytes. In silico prediction and mass spectrometry were used to search for binding partners of miR-122-5p. Mechanistically, miR pulldown, electrophoretic mobility shift assay, and RNA immunoprecipitation confirmed that miR-122-5p interacts with an RNA-binding protein, hnRNPU, in a sequence-specific manner to encapsulate miR-122-5p into large EVs. Upon shuttling into recipient cells, miR-122-5p negatively regulates the expression of the anti-apoptotic gene BCL2, by binding to its 3' untranslated region to regulate its translation, and thereby decreasing the viability of target cardiomyocytes.

Increased levels of circulating pro-apoptotic EV-incorporated miR-122-5p is associated with reduced LVEF after TAVR. Extracellular vesicular shuttling of miR-122-5p regulates the viability and apoptosis of cardiomyocytes in a Bcl2-dependent manner.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Research Foundation (DFG); German Society of Cardiology (DGK)

Coronary artery disease ameliorates extracellular vesicle lncRNA PUNISHER regulates angiogenic response andendothelial cells function via NFkB-dependent mechanism

 

Augmenting evidence indicates that long noncoding RNAs (lncRNAs) are playing a crucial role in diverse cellular/pathological processes. Intercellular transfer of extracellular vesicles (EVs) transmitted lncRNA regulates vascular health and diseases. However, whether lncRNA expression in EVs is regulated in patients with coronary artery disease, is unknown.

A PCR-based lncRNA array analysis revealed that EV-PUNISHER was significantly upregulated in patients with CAD (n=221) compared to healthy subjects. Our data showed that PUNISHER is the most upregulated lncRNA in CAD in accordance with other highly expressed lncRNAs. To examine the specific role of PUNISHER in EC phenotypic regulation, siRNA-mediated silencing in ECs revealed that depletion of PUNISHER suppresses the migration and proliferation of ECs. Moreover, depletion of PUNISHER decreases cell survival by reducing cell viability and proliferation through increased apoptosis and cytotoxicity. In order to investigate EC function in PUNISHER depleted cells, in vitro sprouting and tube formation assay revealed that PUNISHER is an important mediator EC functions, which acts as an anti-angiogenic factor. In vitro atherosclerotic stimuli increased PUNISHER expression in EV/EC in a dose-dependent way. Microarray analysis identified a series of pro- and anti-angiogenic genes as well genes directly involved in cell viability that are differentially regulated.

We confirmed that PUNISHER is incorporated into endothelial microvesicles (EMVs) and transferred to recipient cells by using different experiments. By using lncRNA-FISH and vesicle degradation assays, we showed that PUNISHER is incorporated into EMVs, augmented recipient EC function in vitro upon transfer via EMVs. To examine whether EMV-PUNISHER promotes the EC function, different in vitro functional experiments with ECs confirmed that PUNISHER is an important regulator. Mass spectrometry analysis has revealed EMV contains numerous proteins, including RNA binding proteins such as hnRNPU. By using RNA-pulldown and RNA-IP, we confirmed that PUNISHER interacts with hnRNPU, which facilitates packaging into EMV prior to transfer to recipient EC. The interaction acts as an important positive regulator of cell viability and survival of recipient cells, identified using functional assay. Transcription factor array has shown that PUNISHER regulates NFkB to control cellular viability and apoptosis. A murine re-endothelialization model after injection of 1×107 EVs or bulk ncRNAs revealed that EV-PUNISHER promotes reendothelialization. Ex vivo internalization/uptake of PKH-67-labeled EVs revealed that EVs are detectable in the cross-section of EV-perfused carotid artery.

Our study unveiled for the first time that EV-PUNISHER exerts its function in endothelial cells which might be beneficial in cardiovascular pathologies where the endothelial function is dysregulated. Our data indicate that PUNISHER can be targeted to develop targeted therapeutics.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): German Research Foundation (DFG); German Society of Cardiology (DGK)

Adjustment disorder in cancer patients after treatment: prevalence and acceptance of psychological treatment

Purpose

To investigate the prevalence of adjustment disorder (AD) among cancer patients and the acceptance of psychological treatment, in relation to sociodemographic, clinical, and psychological factors.

Methods

Breast, prostate, and head and neck cancer patients of all stages and treatment modalities (N = 200) participated in this observational study. Patients completed the Hospital Anxiety and Depression Scale, Checklist Individual Strength, Distress Thermometer and problem list. Patients with increased risk on AD based on these questionnaires were scheduled for a diagnostic interview. Patients diagnosed with AD were invited to participate in a randomized controlled trial on the cost-effectiveness of psychological treatment. Participation in this trial was used as a proxy of acceptance of psychological treatment. Logistic regression analyses were used to investigate associated factors.

Results

The overall prevalence of AD was estimated at 13.1%. Sensitivity analyses showed prevalence rates of AD of 11.5%, 15.0%, and 23.5%. Acceptance of psychological treatment was estimated at 65%. AD was associated both with being employed (OR = 3.3, CI = 1.3–8.4) and having a shorter time since diagnosis (OR = 0.3, CI = 0.1–0.8).

Conclusion

Taking sensitivity analysis into account, the prevalence of AD among cancer patients is estimated at 13 to 15%, and is related to being employed and having a shorter time since diagnosis. The majority of cancer patients with AD accept psychological treatment.

Inhibition of Rac1 GTPase Decreases Vascular Oxidative Stress, Improves Endothelial Function, and Attenuates Atherosclerosis Development in Mice

Aims: Oxidative stress and inflammation contribute to atherogenesis. Rac1 GTPase regulates pro-oxidant NADPH oxidase activity, reactive oxygen species (ROS) formation, actin cytoskeleton organization and monocyte adhesion. We investigated the vascular effects of pharmacological inhibition of Rac1 GTPase in mice.

Methods and Results: We treated wild-type and apolipoprotein E-deficient (ApoE^−/−) mice with Clostridium sordellii lethal toxin (LT), a Rac1 inhibitor, and assessed vascular oxidative stress, expression and activity of involved proteins, endothelial function, macrophage infiltration, and atherosclerosis development. LT-treated wild-type mice displayed decreased vascular NADPH oxidase activity and ROS production. Therapeutic LT doses had no impact on behavior, food intake, body weight, heart rate, blood pressure, vascular and myocardial function, differential blood count, and vascular permeability. ApoE^−/− mice were fed a cholesterol-rich diet and were treated with LT or vehicle. LT treatment led to decreased aortic Rac1 GTPase activity, NADPH oxidase activity and ROS production, but had no impact on expression and membrane translocation of NADPH oxidase subunits and RhoA GTPase activity. LT-treated mice showed improved aortic endothelium-dependent vasodilation, attenuated atherosclerotic lesion formation and reduced macrophage infiltration of atherosclerotic plaques. Concomitant treatment of cholesterol-fed ApoE^−/− mice with LT, the specific synthetic Rac1 inhibitor NSC 23766 or simvastatin comparably reduced aortic Rac1 activity, NADPH oxidase activity, oxidative stress, endothelial dysfunction, atherosclerosis development, and macrophage infiltration.

Conclusions: These findings identify an important role of the small GTPase Rac1 in atherogenesis and provide a potential target for anti-atherosclerotic therapy.

Reasons for not reaching or using web-based self-management applications, and the use and evaluation of Oncokompas among cancer survivors, in the context of a randomised controlled trial

INTRODUCTION

The web-based self-management application Oncokompas was developed to support cancer survivors to monitor health-related quality of life and symptoms (Measure) and to provide tailored information (Learn) and supportive care options (Act). In a previously reported randomised controlled trial (RCT), 68% of 655 recruited survivors were eligible, and of those 45% participated in the RCT. Among participants of the RCT that were randomised to the intervention group, 52% used Oncokompas as intended. The aim of this study was to explore reasons for not participating in the RCT, and reasons for not using Oncokompas among non-users, and the use and evaluation of Oncokompas among users.

METHODS

Reasons for not participating were assessed with a study-specific questionnaire among 243 survivors who declined participation. Usage was investigated among 320 participants randomised to the intervention group of the RCT via system data and a study-specific questionnaire that was assessed during the 1 week follow-up (T1) assessment.

RESULTS

Main reasons for not participating were not interested in participation in scientific research (40%) and not interested in scientific research and Oncokompas (28%). Main reasons for not being interested in Oncokompas were wanting to leave the period of being ill behind (29%), no symptom burden (23%), or lacking internet skills (18%). Out of the 320 participants in the intervention group 167 (52%) used Oncokompas as intended. Among 72 non-users, main reasons for not using Oncokompas were no symptom burden (32%) or lack of time (26%). Among 248 survivors that activated their account, satisfaction and user-friendliness were rated with a 7 (scale 0-10). Within 3 (IQR 1-4) sessions, users selected 32 (IQR 6-37) topics. Main reasons for not using healthcare options in Act were that the information in Learn was already sufficient (44%) or no supportive care needs (32%).

DISCUSSION

Main reasons for not reaching or using Oncokompas were no symptom burden, no supportive care needs, or lack of time. Users selected many cancer-generic and tumour-specific topics to address, indicating added value of the wide range of available topics.

Smartphone app-guided secondary prevention in patients with coronary heart disease

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Deutsche Forschungsgemeinschaft

Background 

Coronary artery disease (CAD) is the leading cause of death worldwide. Lifestyle change is a crucial part of secondary prevention. Only 30% of CAD patients follow the corresponding guideline recommendations. The widespread adoption of smartphones offers the opportunity to integrate secondary prevention into the daily routine of CAD patients.

Purpose 

The purpose of this study was to show that smartphone-guided secondary prevention (SGSP) could achieve lifestyle changes and a gain of disease specific knowledge among CAD patients. 

Methods 

We developed an app to integrate secondary prevention into CAD patients’ everyday life. The app provided a daily 15-minute program that included video-guided exercises, video sessions with background information about CAD, and a tool to record blood pressure and heart rate once a day.

The SGSP app was tested with the primary outcome of 28-day adherence. The secondary outcome was a composite of self-reported behavioural changes, gain of knowledge about cardiovascular risk factors and an increase in quality of life.

Results 

Of the 66 patients screened, 43 (65%) were included into the study and, of those, 17 (40%) used the app continuously for 28 days. From this group, 14 (82%) were physically more active and ten (59%) improved their dietary habits. Usage of the SGSP app was also associated with a gain of knowledge about cardiovascular risk factors (70% physical activity, 59% healthy diet).

Conclusion 

The regular use of a SGSP app appears to support lifestyle changes in patients with CAD.

Primary and secondary endpoints Results Overall(n = 17) P-Value Adherence (28 days) 17 (39.5) 0.34 Behavioural change Significantly increased physical activity no. (%) 14 (82.4) 0.08 Implemented a healthier diet no. (%) 10 (58.8) 0.64 Relevant gain of knowledge about CVRF Physical activity no. (%) 12 (70.6) 0.13 Unhealthy diet no. (%) 10 (58.8) 1.00 Smoking no. (%) 1 (5.9) 0.47 Stress no. (%) 7 (41.2) 0.13 Potential for long-term use Willingness to use the App over a long time period (>28 days), no. (%) 15 (88.2) 1.00

Abstract Figure.

The eHealth self-management application 'Oncokompas' that supports cancer survivors to improve health-related quality of life and reduce symptoms: which groups benefit most?

BACKGROUND

Oncokompas is a web-based self-management application that supports cancer survivors to monitor their health-related quality of life (HRQOL) and symptoms, and to obtain personalised feedback and tailored options for supportive care. In a large randomised controlled trial among survivors of head and neck cancer, colorectal cancer, and breast cancer and (non-)Hodgkin lymphoma, Oncokompas proved to improve HRQOL, and to reduce several tumour-specific symptoms. Effect sizes were however small, and no effect was observed on the primary outcome patient activation. Therefore, this study aims to explore which subgroups of cancer survivors may especially benefit from Oncokompas.

MATERIALS AND METHODS

Cancer survivors (n = 625) were randomly assigned to the intervention group (access to Oncokompas, n = 320) or control group (6 months waiting list, n = 305). Outcome measures were HRQOL, tumour-specific symptoms, and patient activation. Potential moderators included socio-demographic (sex, age, marital status, education, employment), clinical (tumour type, stage, time since diagnosis, treatment modality, comorbidities), and personal factors (self-efficacy, personal control, health literacy, Internet use), and patient activation, mental adjustment to cancer, HRQOL, symptoms, and need for supportive care, measured at baseline. Linear mixed models were performed to investigate potential moderators.

RESULTS

The intervention effect on HRQOL was the largest among cancer survivors with low to moderate self-efficacy, and among those with high personal control and those with high health literacy scores. Cancer survivors with higher baseline symptom scores benefitted more on head and neck (pain in the mouth, social eating, swallowing, coughing, trismus), and colorectal cancer (weight) specific symptoms.

DISCUSSION

Oncokompas seems most effective in reducing symptoms in head and neck cancer and colorectal cancer survivors who report a higher burden of tumour-specific symptoms. Oncokompas seems most effective in improving HRQOL in cancer survivors with lower self-efficacy, and in cancer survivors with higher personal control, and higher health literacy.

Incidence, Risk Factors and Impact on Long-Term Outcome of Postoperative Delirium After Transcatheter Aortic Valve Replacement

Background: The aim of the present study was to analyze incidence, risk factors, and association with long-term outcome of postoperative delirium (POD) after transcatheter aortic valve replacement (TAVR).

Methods: Six hundred and sixty one consecutive patients undergoing TAVR were prospectively enrolled from January 2016 to December 2017. POD was assessed regularly during ICU-stay using the CAM-ICU test.

Results: The incidence of POD was 10.0% (n = 66). Patients developing POD were predominantly male (65%), had higher EuroSCORE II (5.4% vs. 3.9%; P = 0.041) and were more often considered frail (70% vs. 26%; P < 0.001). POD was associated with more peri-procedural complications including vascular complications (19.7 vs. 9.4; P = 0.017), bleeding (12.1 vs. 5.4%; P = 0.0495); stroke (4.5 vs. 0.7%; P = 0.025), respiratory failure requiring ventilation (16.7% vs. 1.8%; P < 0.001), and pneumonia (34.8% vs. 7.1%; P < 0.001). Consequently, patients with POD had significantly longer ICU- (7.9 vs. 3.2 days P < 0.001) and hospital-stay (14.9 vs. 9.0 days; P < 0.001), and higher in-hospital mortality (6.1 vs. 2.1%; P = 0.017). Logistic regression analysis identified male sex (odds ratio (OR) 2.2 [95% confidence interval (CI) 1.2–4.0); P = 0.012], atrial fibrillation [OR 3.0 (CI 1.6–5.6); P < 0.001], frailty [OR 4.3 (CI 2.4–7.9); P < 0.001], pneumonia [OR 4.4 (CI 2.3–8.7); P < 0.001], stroke [OR 7.0 (CI 1.2–41.6); P = 0.031], vascular complication [OR 2.9 (CI 1.3–6.3); P = 0.007], and general anesthesia [OR 2.0 (CI 1.0–3.7); P = 0.039] as independent predictors of POD. On Cox proportional hazard analysis POD emerged as a significant predictor of 2-year mortality [HR 1.89 (CI 1.06–3.36); P = 0.030].

Conclusion: POD is a frequent finding after TAVR and is significantly associated with reduced 2-year survival. Predictors of delirium include not only peri-procedural parameters like stroke, pneumonia, vascular complications and general anesthesia but also baseline characteristics as male sex, atrial fibrillation and frailty.

Smartphone-guided secondary prevention for patients with coronary artery disease

Introduction

Coronary artery disease (CAD) is the leading cause of death worldwide. Lifestyle change is a crucial part of secondary prevention. Only 30% of CAD patients follow the corresponding guideline recommendations. The widespread adoption of smartphones offers the opportunity to integrate secondary prevention into the daily routine of CAD patients.

Methods

We developed an app to integrate secondary prevention into CAD patients’ everyday life (smartphone-guided secondary prevention, SGSP). The app provided a daily 15-minute program that included video-guided exercises, video sessions with background information about CAD, and a tool to record blood pressure and heart rate once a day. The SGSP app was tested with the primary outcome of 28-day adherence. The secondary outcome was a composite of (1) self-reported behavioral changes, (2) gain of knowledge about cardiovascular risk factors, and (3) an increase in quality of life.

Results

Of the 66 patients screened, 43 (65%) were included into the study and, of those, 17 (40%) used the app continuously for 28 days. From this group, 14 (82%) were physically more active and ten (59%) improved their dietary habits. Usage of the SGSP app was also associated with a gain of knowledge about cardiovascular risk factors (70% physical activity, 59% healthy diet).

Conclusion

The regular use of a SGSP app appears to support lifestyle changes in patients with CAD.

Vascular pathologies in chronic kidney disease: pathophysiological mechanisms and novel therapeutic approaches

Cardiovascular disease (CVD) is a major cause of death in patients with chronic kidney disease (CKD). Both conditions are rising in incidence as well as prevalence, creating poor outcomes for patients and high healthcare costs. Recent data suggests CKD to be an independent risk factor for CVD. Accumulation of uremic toxins, chronic inflammation, and oxidative stress have been identified to act as CKD-specific alterations that increase cardiovascular risk. The association between CKD and cardiovascular mortality is markedly influenced through vascular alterations, in particular atherosclerosis and vascular calcification (VC). While numerous risk factors promote atherosclerosis by inducing endothelial dysfunction and its progress to vascular structural damage, CKD affects the medial layer of blood vessels primarily through VC. Ongoing research has identified VC to be a multifactorial, cell-mediated process in which numerous abnormalities like mineral dysregulation and especially hyperphosphatemia induce a phenotype switch of vascular smooth muscle cells to osteoblast-like cells. A combination of pro-calcifying stimuli and an impairment of inhibiting mechanisms like fetuin A and vitamin K-dependent proteins like matrix Gla protein and Gla-rich protein leads to mineralization of the extracellular matrix. In view of recent studies, intercellular communication pathways via extracellular vesicles and microRNAs represent key mechanisms in VC and thereby a promising field to a deeper understanding of the involved pathomechanisms. In this review, we provide an overview about pathophysiological mechanisms connecting CKD and CVD. Special emphasis is laid on vascular alterations and more recently discovered molecular pathways which present possible new therapeutic targets.

AIM2 Stimulation Impairs Reendothelialization and Promotes the Development of Atherosclerosis in Mice

Background: Atherosclerosis has been shown to result from chronic inflammation caused by constitutive activation of the pattern recognition receptors (PRR), which are principle effectors of the innate immune system. PRR are present in the endosome or on the cellular membrane and can sense the aberrant release of nucleic acids, which is often a sign of acute or chronic cellular damage. Absent in melanoma 2 (AIM2) is a PRR that is expressed by vascular cells and specializes in detecting cytoplasmic double-stranded DNA (dsDNA). Activation of AIM2 leads eventually to activation of the inflammasome, but the role of AIM2 in vascular disease and atherosclerosis has not been well-studied. Therefore, in this study we took advantage of acute and chronic models of vascular injury to determine the biological role of AIM2 in atherogenesis. Methods and Results: We were able to induce significant release of proinflammatory cytokines in mice through the intravenous injection of a synthetic ligand for AIM2, double-stranded poly dA:dT. This cytokine release was shown to impair reendothelialization of the carotid artery and increase the number of circulating endothelial microparticles (EMP) after acute denudation, compared to treatment with vehicle. We saw an increase in the production of reactive oxygen species in the aorta, the number of circulating EMP, and, most interestingly, atherosclerotic plaque formation in apolipoprotein E-deficient (ApoE^-/-) mice when they received continual subcutaneous poly dA:dT, in contrast to vehicle-treated animals. Finally, treatment with poly dA:dT did not impair vascular reendothelialization in AIM2^-/- mice compared to vehicle controls in the carotid artery injury model. Conclusion: Overall, our data suggest that AIM2, as a known regulator of the inflammasome, is an active participant in atherogenesis, and highlight the importance of fully understanding the pathological mechanisms involved. It seems to be worth of further exploration as a therapeutic target, and future studies focusing on the effects of AIM2 activation as well as its pharmacological inhibition may reveal promising new therapeutic concepts for the treatment of atherosclerosis.

HnRNPU regulates intra- and intercellular microRNA trafficking in a sequence specific manner

Introduction

The transfer of microRNAs (miRs) through extracellular vesicles (EVs) is a well-established mechanism of vascular intercellular communication. In a previous study, we have identified the heterogeneous nuclear ribonucleoprotein U (hnRNPU) as a potent regulator of the vesicular export of a specific set of miRs in endothelial cells (ECs). Downregulation of hnRNPU caused an increased export of miRs into large EVs and lead to a reduction of the migratory capacity in EV up-taking ECs. The underlying mechanism, how hnRNPU recognizes only certain miRs and regulates their export, however, remained unclear.

Methods and results

Increasingly exported microRNAs into EVs after siRNA-mediated downregulation of hnRNPU were identified in a miR array and used to perform a sequence analysis with the Multiple Em for Motif Elicitation tool (MEME). The software identified the motif AAMRUGCU to be significantly enriched within the regulated miRs. Binding of hnRNPU to miR-30c-5p, which was one of the most significantly increased miRs in EVs upon downregulation of hnRNPU, was confirmed in an immunoprecipitation and an RNA-pulldown experiment. In order to investigate, if the in silico motif AARUGCU was the binding site of miR-30c-5p and hnRNPU an electrophoretic mobility shift assay (EMSA) was conducted with native miR-30c-5p, mutated miR-30c-5p as well as miR-125a-3p as a negative control. The EMSA showed that a partial mutation, which conserves the purine / pyrimidine structure in the motif of miR-30c-5p does not affect binding, while a complete disruption of the motif structure abolishes binding of hnRNPU and miR-30c-5p. Furthermore, we found that hnRNPU protects miR-30c-5p from rapid degradation after transcriptional blockage by Actinomycin D. Binding of miR-30c-5p to the predominantly nuclearly expressed hnRNPU retains miR-30c-5p in the nucleus. HnRNPU knockdown leads to a redistribution of miR-30c-5p from the nucleus to the cytoplasm. The regulating effect of hnRNPU expression on vesicular miR export was confirmed by overexpression of hnRNPU through plasmid transfection. In contrast to siRNA-mediated downregulation, overexpression of hnRNPU lead to a decrease of vesicular miR-30c-5p levels. In order to extent our findings to other cell types with high vascular relevance, siRNA mediated downregulation of hnRNPU was performed in human cardiac fibroblasts (HCF). Similar to our findings in ECs, downregulation of hnRNPU in HCFs lead to an increase in vesicular miR-30c-5p levels.

Conclusion

In conclusion, we show that hnRNPU binds miRs, which contain the motif AAMRUGCU. This leads to nuclear retainment, stabilization and inhibits vesicular export, which can be further decreased by overexpression of hnRNPU and enhanced by downregulation of hnRNPU. The effect is not restricted to ECs but applies also to HCFs. hnRNPU may therefore be an important target to influence intra- and intercellular trafficking of a specific set of miRs including miR-30c-5p.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Medical faculty of the University of Bonn, German Cardiac Society

TAC induced cardiac hypertrophy leads to increased levels of circulating microvesicles

Introduction

Cardiac hypertrophy and heart failure are wide spread diseases of elderly patients in the industrialised world and drive a majority of healthcare costs in these countries. Therefore, there is a high urgency to understand the development and progress of heart failure to find new therapeutic strategies especially in early stages. Microvesicles are involved in the development and propagation of almost all cardiac diseases and increased levels of circulating microvesicles can be found in blood of patients with chronic heart failure. To point out the underlying mechanisms and to provide a new animal model based approach, we investigated microvesicle (MV)-release in mice that underwent Transverse Aortic Constriction (TAC). TAC is a common method to induce cardiac hypertrophy and heart failure in mice by inducing pressure overload. We hypothesized that TAC leads to upregulation of total MV and MV of specific origin.

Methods and results

Wildtype C57BL/6 mice underwent TAC to induce cardiac hypertrophy and heart failure. After TAC, mice developed cardiac hypertrophy as determined by altered heart weight/ bodyweight ratio, end-diastolic and end-systolic diameter and decreased fractional shortening. Total numbers of circulating microvesicles were detected 1, 4 and 12 weeks after TAC. We found that total numbers of circulating macrovesicles raised in a time dependent manner. Similar observations could be done with samples stained for annexin V, although results were not significant. Moreover, microvesicles were stained with specific surface markers for lymphocyte (CD3), monocyte (CD14), endothelial cells (CD31), thrombocytes (CD41), B-cells (CD45) and neutrophils (Lys6). One week after TAC increased numbers of specific microvesicles could be detected which in the course declined rapidly. Only microvesicles subgroup of lymphocyte origin showed significant increase one week after TAC-OP.

Conclusion

In this study, we show that total number of circulating microvesicles raise after TAC over an observation period of 12 weeks. Furthermore, we found that increased numbers of circulating microvesicles of specific origin like lymphocytes, monocytes, endothelial cells, thrombocytes, B-cells and neutrophils showed a trend towards increased levels one week after TAC with a rapid decline in subsequent detection. To our knowledge this is the first time that the impact of TAC on number of circulating microvesicles in mice was investigated. Future studies should characterize the content and effects of these MV on recipient cells to elucidate possible contributions to heart failure progression or protective effects. Detecting new harmful or protective effects of heart failure triggered by circulating microvesicles could offer new highly needed approaches to suppress heart failure development or deliver the possibility to develop new drugs for heart failure treatment.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Else Kröner-Fresenius

Levels of platelet derived extracellular vesicles in the left atrial appendage are higher in patients with permanent atrial fibrillation

Introduction

Atrial fibrillation (AF) is a frequent arrhythmic disease and one of the most important causes of thrombembolic disease due to intracardiac thrombus formation. The left atrial appendage has been identified as the structure, where thrombus formation typically takes place in AF patients. Previous studies have shown thrombus formation is more frequent in permanent, than in paroxysmal or persistent AF. Underlying causes for this finding, however, remain unclear. Recently, it has been shown, that large extracellular vesicles (Microvesicles, MVs) are mediators of platelet activation. The aim of this study is therefore to investigate if the AF subtype correlates with the regional abundance of platelet derived MVs in the left atrial appendage.

Methods and results

In order to address this question blood samples from 59 consecutive patients undergoing left and right atrial catheterization were collected from the right atrium (RA), the left atrium (LA) and the left atrial appendage (LAA). 49% of the patients had permanent AF, 34% had non-permanent AF and 17% had no history of AF. MVs were isolated from 150 μL citrate plasma by a four-step differential centrifugation protocol (20000g x 40 min as main pelleting step). The MVs were characterized by immunoblotting and nanoparticle tracking analysis. The size of the MVs ranged between 50 and 600 nm and the MVs were shown to carry typical markers such as Annexin V. For flowcytometric analysis and quantification, Calcein AM was used to identify vesicles and CD31-PE, CD41-APC, CD235a-PE-Cy7 were applied to differentiate between platelet-derived MVs (PMVs, CD41+ CD31+), endothelial cell-derived MVs (EMVs, CD41- CD31+) and Red blood cell-derived MVs (RMVs, CD235a+). Fluorescence minus one controls, a concentration row and detergent mediated degradation were used to confirm specific staining of MVs. Total MV numbers (Calcein + events) did not differ significantly between the three cardiac localizations. In the left atrial appendage, the proportion of PMV was significantly higher in permanent AF patients compared to non-permanent AF. EMV numbers only differed in the right atrium, where permanent AF patients exhibited significantly lower numbers of EMVs compared to no AF controls. No differences between the groups were detected for RMV.

Conclusion

In the present study, we found that PMV levels in the left atrial appendage correlate with the type of atrial fibrillation (permanent vs non-permanent). PMVs have been connected to platelet activation and thrombus formation. These results may help to better understand how different types of atrial fibrillation cause different rates of thrombus formation in the LAA.

PMV and EMV numbers by AF subtype

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Medical Faculty University Bonn

The role of noncoding RNAs during aortic valve stenosis

Background

Aortic valve stenosis (AVS) is the most common valve disease worldwide. Thought to be a purely degenerative disease, it is now clear that shear stress/endothelial dysfunction, lipid deposition and inflammation lead to calcification and stenosis of the valve. There is evidence, that extracellular vesicles (EVs) are actively involved in calcification processes. Practically all cells, including endothelial cells, can generate EVs, which can be shed into the blood stream and into the interstitial space. EVs contain lipids, proteins and nucleic acids, including noncoding RNAs (ncRNAs). EVs can be taken up by acceptor cells and their cargo, especially the ncRNA content, can change the phenotype of these cells. NcRNAs have been shown to have protective and damaging properties in AVS, which can lead to disease progression. EVs are actively involved in atherosclerosis and vascular calcification, but their role during AVS formation remains largely unknown.

Purpose

We hypothesize, that EV-derived ncRNAs play a crucial role during calcification of the aortic valve through regulation of endothelial to mesenchymal transition (EndMT) and calcification of valvular interstitial cells.

Methods and results

In initial screening experiments, we investigated ncRNA (micro RNA, miRNA and long noncoding RNA, lncRNA) content in aortic valve tissue from explanted human aortic valves from patients undergoing surgical aortic valve replacement. There is a differential expression of miRNAs and lncRNAs in aortic valve tissue from patients with AVS and patients without AVS. We could also show a differential packaging of ncRNAs into EVs generated from patient aortic valve tissues. Furthermore, ncRNA expression in aortic valve tissue is altered in a “wire-injury” mouse model of AVS. We can demonstrate in vitro that EVs and their content can be transferred from valvular endothelial cells (VECs) to valvular interstitial cells (VICs) and vice versa. Additionally, we have established an isolation method of VECs and VICs from human samples. To identify ncRNAs involved in EndMT, we are investigating the effect of laminar and pulsatile flow on the expression of ncRNAs in vitro. We can demonstrate that different flow patterns lead to a vast change in ncRNA expression in primary VECs. Downstream effects of identified ncRNAs are currently under investigation in our in vitro calcification and EndMT models. Transfection of VICs with miRNA mimics and inhibitors and lentiviral transduction of our identified targets lead to an altered calcification potential of valve cells.

Conclusion

The analysis of the cell type specific expression of ncRNAs and the intercellular communication via EVs will greatly help our understanding of the pathomechanisms leading to valvular calcification. Pathway analysis will generate new targets that could be used to develop therapeutics to ameliorate disease progression. EV-based miRNA mimics and inhibitors could be used to treat valvular calcification.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft, TRR259; Else-Kröner-Fresenius

Toll-like-receptor-3 function is critical for aortic valve stenosis development in mice

Background

Aortic valve stenosis (AS) is the most common valve diseases in the western world. After having been considered a passive degenerative process, which develops as an inevitable consequence of age-related valvular degeneration, basic research of the last two decades has led to a paradigm shift. It is now believed that AS pathophysiology is driven by distinct molecular and cellular mechanisms which include inflammatory pathways. In recent years, Toll-like-receptor-3 (TLR3) has emerged as a major regulator of vascular inflammation. TLR3 is a lysosomal pattern recognition receptor that recognizes single and double stranded RNA. Its activation leads to expression of pro-inflammatory cytokines via NFkb activation. The role of TLR3 in the development of AS has never been investigated.

Methods

Severe AS was induced in Wildtype-, ApoE- and TLR3/ApoE−/− mice. For this, a coronary springwire was used to induce an endothelial injury under echocardiographic guidance. Stenosis development was confirmed via ultrasound examinations. To inhibit TLR-3 activation, TLR3/RNA- Complex inhibitor C4a was injected every 48h after wire injury in WT mice. Valves were explanted and stained with hematoxylin/eosin (valve thickening) or anti-68 (macrophage infiltration). Valves from patients who received aortic valve replacement due to AS or aortic regurgitation (AR) were collected and mRNA levels of TLR3 and MyD88 were measured with use of quantitative-PCR.

Results

To evaluate weather TLR3 effects AS development in mice, we subjected TLR3/ApoE double- and ApoE knockout mice to our model of wire-induced AS. Surprisingly, TLR3 deficient mice failed to develop AS after wire injury. Peak velocity measurements showed no increase and histological analysis showed lower aortic valve area and macrophage infiltration compared to control mice. In order to pharmacological inhibit TLR3, WT mice were treated with C4a after wire injury. Compared to PBS control, C4a mice also did not develop AS upon wire injury. Trans-aortic valve peak velocity levels were significantly lower in C4a mice. Histological analysis underlined these results and showed thinner aortic valves and decreased macrophage infiltration in C4a mice comparted to control animals. To confirm our hypothesis, the expression of TLR3 and its downstream effector MyD88 were measured in human aortic valve specimens. qPCR analysis revealed decreased TLR3 and MyD88 expression in patients with AS compared to patients with AR.

Conclusion

In the presented study, we present first data that theTLR3 has a crucial role in the development of AS in mice. The exact downstream effects after TLR3 activation in AS need to be further investigated.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)

MicroRNAs As Master Regulators of Atherosclerosis: From Pathogenesis to Novel Therapeutic Options

Significance: Cardiovascular disease (CVD) remains the major cause of morbidity and mortality worldwide. Accumulating evidence indicates that atherosclerosis and its sequelae, coronary artery disease, contribute to the majority of cardiovascular deaths. Atherosclerosis is a chronic inflammatory disease of the arteries in which atherosclerotic plaques form within the vessel wall. Epidemiological studies have identified various risk factors for atherosclerosis, such as diabetes, hyperlipidemia, smoking, genetic predisposition, and sedentary lifestyle. Recent Advances: Through the advancement of genetic manipulation techniques and their use in cardiovascular biology, it was shown that small RNAs, especially microRNAs (miRNAs), are dynamic regulators of disease pathogenesis. They are considered to be central during the regulation of gene expression through numerous mechanisms and provide a means to develop biomarkers and therapeutic tools for the diagnosis and therapy of atherosclerosis. Circulating miRNAs encapsulated within membrane-surrounded vesicles, which originate from diverse subcellular compartments, are now emerging as novel regulators of intercellular communication. The miRNAs, in both freely circulating and vesicle-bound forms, represent a valuable tool for diagnosing and monitoring CVD, recently termed as "liquid biopsy." Critical Issues: However, despite the recent advancements in miRNA-based diagnostics and therapeutics, understanding how miRNAs can regulate atherosclerosis is still crucial to achieving an effective intervention and reducing the disease burden. Future Directions: We provide a landscape of the current developmental progression of RNA therapeutics as a holistic approach for treating CVD in different animal models and clinical trials. Future interrogations are warranted for the development of miRNA-based therapeutics to overcome challenges for the treatment of the disease.

Echinococcus multilocularis in red foxes in North Belgium: Prevalence and trends in distribution

A cross-sectional systematic sampling was carried out during three consecutive winters from 2012 to 2015, to update the knowledge on the fox tapeworm (Echinococcus multilocularis) distribution in the red fox (Vulpes vulpes) in Flanders. Earlier studies reported the low endemicity status of this tapeworm in the northern region of Belgium, in contrast to the south of the country and neighbouring countries. Using a modified Segmental Sedimentation and Counting Technique, followed by PCR-RFLP and sequencing, 923 foxes' intestines were examined for the presence of E. multilocularis. Based on microscopic examination, 38 out of 923 foxes were suspected to be infected with either E. multilocularis or Amoebotaenia spp., of which 19 were molecularly confirmed to be E. multilocularis, 18 were found positive for Amoebotaenia spp. and one was negative. The overall prevalence for E. multilocularis of 2.1% confirms the low endemicity of the fox tapeworm in Flanders. However, in one area in the most eastern part of Flanders (Voeren), neighbouring the Netherlands and Wallonia, a prevalence of 57% (12/21) was observed. Continuous monitoring of the fox tapeworm remains needed to assess spatio-temporal trends in distribution and to assess the risk of this zoonotic infection in Europe. The challenging differential diagnosis of E. multilocularis and Amoebotaenia spp. based on microscopic examination calls for attention.

Body image distress in head and neck cancer patients: what are we looking at?

PURPOSE

The aim of the present study is to investigate the prevalence of body image distress among head and neck cancer (HNC) patients after treatment and to examine its association with sociodemographic and clinical factors, health-related quality of life (HRQOL), HNC symptoms, sexuality, self-compassion, and psychological distress. Second, we aim to explore daily life experiences of HNC patients regarding body image.

METHODS

A cross-sectional survey among HNC patients investigated the prevalence of body image distress based on the Body Image Scale. Multivariable logistic regression analysis was applied to study associations with sociodemographic and clinical factors, HRQOL (EORTC QLQ-C30), HNC symptoms (QLQ-HN43), sexuality (FSFI-6; IIEF-5), self-compassion (SCS-SF), and psychological distress (HADS). Qualitative data from a body image writing intervention was used to explore experiences in daily life related to body image.

RESULTS

Body image distress was prevalent in 13-20% (depending on cut-off scores) of 233 HNC patients. Symptoms of depression (p < 0.001), younger age (p < 0.001), problems with social contact (p = 0.001), problems with wound healing (p = 0.013), and larger extent of surgery (p = 0.014) were associated with having body image distress. This model explained 67% of variance. Writing interventions of 40 HNC patients showed that negative body image experiences were related to appearance and function, with social functioning problems described most often.

CONCLUSION

Prevalence of body image distress in HNC patients, using different cut-off scores, is 13-20%. Younger patients, patients after extensive surgery, and patients who had wound healing problems are most at risk. There is a significant association between body image distress and depressive symptoms and social functioning.

Cost-utility of an eHealth application 'Oncokompas' that supports cancer survivors in self-management: results of a randomised controlled trial

Purpose

The eHealth self-management application ‘Oncokompas’ was developed to support cancer survivors in monitoring health-related quality of life (HRQOL) and symptoms, and obtaining personalized feedback and options for supportive care. The aim of this study was to assess the cost-utility of Oncokompas compared with care as usual (CAU) among cancer survivors.

Methods

Survivors were randomly allocated to the intervention or control group. Direct (non-)medical, indirect non-medical costs, and HRQOL were measured at 3- and 6-month follow-up, using iMTA Medical Consumption and Productivity Costs and the EuroQol-5D questionnaires. Mean cumulative costs and quality-adjusted life-years (QALYs) were compared between both groups.

Results

In total, 625 survivors were randomized into intervention (n = 320) or control group (n = 305). Base case analysis showed that incremental costs from a societal perspective were − €163 (95% CI, − 665 to 326), and incremental QALYs were 0.0017 (95% CI, − 0.0121 to 0.0155) in the intervention group compared with those in the control group. The probability that, compared with CAU, Oncokompas is more effective was 60%, less costly 73%, and both more effective and less costly 47%. Sensitivity analyses showed that incremental costs vary between − €40 and €69, and incremental QALYs vary between − 0.0023 and − 0.0057.

Conclusion

Oncokompas is likely to be equally effective on utilities, and not more expensive than CAU, and will therefore contribute to sustainable cancer survivorship care in a (cost-)effective manner.

Implications for Cancer Survivors

Oncokompas seems to improve HRQOL and reduces the burden of several tumour-specific symptoms, while costs from a societal perspective are similar to CAU.

Electronic supplementary material

The online version of this article (10.1007/s11764-020-00912-9) contains supplementary material, which is available to authorized users.

The RNA-binding protein hnRNPU regulates the sorting of microRNA-30c-5p into large extracellular vesicles

The transfer of microRNAs (miRs) via extracellular vesicles (EVs) is a functionally relevant mechanism of intercellular communication that regulates both organ homoeostasis and disease development. Little is known about the packaging of miRs into EVs. Previous studies have shown that certain miRs are exported by RNA-binding proteins into small EVs, while for other miRs and for large EVs, in general, the export mechanisms remain unclear. Therefore, a proteomic analysis of endothelial cell-derived large EVs was performed, which revealed that heterogeneous nuclear ribonucleoprotein U (hnRNPU) is abundantly present in EVs. EVs were characterized by electron microscopy, immunoblotting and nanoparticle tracking analysis. Taqman microRNA array and single qPCR experiments identified specific miR patterns to be exported into EVs in an hnRNPU-dependent way. The specific role of hnRNPU for vesicular miR-sorting was confirmed independently by gain- and loss-of-function experiments. In our study, miR-30c-5p was the miR whose export was most significantly regulated by hnRNPU. Mechanistically, in silico binding analysis showed that the export of miRs into EVs depends on the binding efficiency of the respective miRs to hnRNPU. Among the exported miRs, a significant enrichment of the sequence motif AAMRUGCU was detected as a potential sorting signal. Experimentally, binding of miR-30c-5p to hnRNPU was confirmed independently by RNA-immunoprecipitation, electrophoretic mobility shift assay and reciprocally by miR-pulldown. Nuclear binding of miR-30c-5p to hnRNPU and subsequent stabilization was associated with a lower cytoplasmatic abundance and consequently reduced availability for vesicular export. hnRNPU-dependent miR-30c-5p export reduced cellular migration as well as pro-angiogenic gene expression in EV-recipient cells. In summary, hnRNPU retains miR-30c-5p and other miRs and thereby prevents their export into large EVs. The data presented provide a novel and functionally relevant mechanism of vesicular miR export.