bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reverse use dependence of calcium sensitizer levosimendan on action potential duration shortening prevents ventricular arrhythmia during therapeutic hypothermia
Authors: Hsieh Y.C , Li C.H , Lin J.C , Weng C.J , Chien Y.S , Lin S.F , Huang J.L , Wu T.J 
Published: November 2020

Abstract

Background
Therapeutic hypothermia (TH) increases the risk of ventricular arrhythmia (VA) by prolonging action potential duration (APD) and steepening the APD restitution (APDR). The calcium sensitizer levosimendan, a medication for heart failure treatment, has been reported to shorten APD by enhancing ATP-sensitive K current and affect the APDR.

Purpose
We hypothesized that levosimendan might shorten the already prolonged APD particularly at long pacing cycle length (PCL), thus decreases the maximal slope of APDR, and prevent VA during TH.

Methods
Langendorff-perfused isolated rabbit hearts were subjected to 15-min TH (30°C) followed by 30-min treatment with levosimendan (0.5 μM, n=9) or vehicle (n=8). Using an optical mapping system, APD was evaluated by S1 pacing and APDR curve was plotted using APD70 versus diastolic interval. Ventricular fibrillation (VF) inducibility was evaluated by burst pacing for 30 s at the shortest PCL that achieved 1:1 ventricular capture.

Results
The APD was shortened from 259±8 ms at TH to 241±18 ms after levosimendan infusion at long PCL of 400 ms (p=0.024). However, at short PCL of 280 ms, the APD was not changed before (194±19) and after (188±23) levosimendan during TH (p=0.61). Levosimendan decreases the maximal slope of APDR curve from 1.99±0.65 at TH to 1.41±0.32 after adding levosimendan (p=0.034). The VF inducibility was decreased by levosimendan from 39±30% at 30°C to 14±12% with levosimendan (p=0.023). In control hearts, the maximal slope of APDR (p=0.75) and VF inducibility (p=0.12) were not changed by vehicle during TH.

Conclusion
Levosimendan might protect the hearts against VA during TH by shortening APD at long PCL and flattening the APDR. Enhancing ATP-sensitive K current with levosimendan during TH might be a novel approach to prevent VA during TH.

Funding Acknowledgement
Type of funding source: None
Suppression of ventricular arrhythmia by mitochondrial calcium uptake via mitochondrial calcium uniporter in the ischemic heart failure mice
Authors: Hagiwara H , Watanabe M , Fujioka Y , Koya T , Nakao M , Takahashi Y , Kamada R , Ohba Y , Anzai T 
Published: November 2020

Abstract

Background
In heart failure (HF), diastolic calcium (Ca) leak from sarcoplasmic reticulum (SR) via ryanodine receptor (RyR) causes delayed after depolarization (DAD), leading ventricular arrhythmias (VAs). Recent study reported that Ca uptake into mitochondria via mitochondrial calcium uniporter (MCU) suppress Ca waves (CaWs) and DAD in catecholaminergic polymorphic ventricular tachycardia, in which diastolic Ca leak is thought to be a major cause of VAs as in HF. However, such anti-arrhythmic effect of mitochondrial Ca uptake via MCU remains unclear in HF.

Purpose
We sought to investigate whether mitochondrial Ca uptake via MCU decreases CAWs and VAs incidence in ischemic HF mice.

Methods
Ten-week-old male C57BL/6J mice were divided into 2 groups; sham operation mice (Sham) or HF mice (HF) in which myocardial infarction was induced by left coronary artery ligation. After 4–6 weeks, cardiomyocyte or mitochondria was isolated respectively from the myocardium of Sham and the non-infarct myocardium of HF. Influence of MCU activation on Ca dynamics, VA inducibility and left ventricular hemodynamics were evaluated using Kaemenpferol, a MCU activator. Intracellular Ca dynamics and mitochondrial Ca uptake were measured in isolated cardiomyocytes loaded with Fluo-4 AM on an epifluorescence microscopy and by estimating the extra-mitochondrial Ca reduction with Fluo-5N on a spectrofluoro-photometer, respectively. VAs was induced by programmed stimulation in the Langendorff perfused hearts. Left ventricular (LV) pressure was measured using a microtip transducer catheter. Finally, the effect of intravenous administration of Kaempferol (5mg/kg) on hemodynamic parameters was examined 30 minutes after administration in Sham and HF.

Results
HF mice showed left ventricular dysfunction, as well as the increased heart and lung weights compared to Sham. MCU protein expression in cardiomyocytes did not differ between Sham and HF. Kaempferol increased mitochondrial Ca uptake in the isolated mitochondria both in Sham and HF. The number of the diastolic CaWs was higher in HF compared to Sham. Such increased number of CaWs in HF was attenuated by 10 μM Kaempferol, which was, however, abolished by a MCU blocker Ruthenium Red. The incidence of induced VA was significantly higher in HF than Sham, which was suppressed by Kaempferol. In vivo measurements, intravenous administration of Kaempferol did not show significant changes in hemodynamic parameters in Sham and HF mice.

Conclusions
Mitochondrial Ca uptake via MCU suppresses CaWs and VAs, but did not change LV hemodynamics in HF. Whereas traditional antiarrhythmic drugs have limited use in heart failure patients, a novel strategy that promotes Ca uptake into mitochondria might be a new and safer option for treating VAs in HF.

Funding Acknowledgement
Type of funding source: None
The genetic architecture of left ventricular non-compaction reveals both substantial overlap with other cardiomyopathies and a distinct aetiology in a subset of cases
Authors: Walsh R , Mazzarotto F , Hawley M , Beltrami M , Beekman L , Boschi B , Girolami F , Roberts A , Cerbai E , Cook S , Ware J , Funke B , Olivotto I , Bezzina C , Barton P 
Published: November 2020

Abstract

Background
Left ventricular non-compaction (LVNC) is a condition characterised by trabeculations in the myocardial wall and is the subject of considerable conjecture as to whether it represents a distinct pathology or a secondary phenotype associated with other cardiac diseases, particularly cardiomyopathies.

Purpose
To investigate the genetic architecture of LVNC by identifying genes and variant classes robustly associated with disease and comparing these to other genetically characterised cardiomyopathies.

Methods
We performed rare variant association analysis using six different LVNC cohorts comprising 840 cases together with 125,748 gnomAD population controls and compared results to similar analyses with dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM) cases.

Results
We observed substantial overlap in genes and variant classes enriched in LVNC and DCM/HCM, indicating that in many cases LVNC belongs to a spectrum of more established cardiomyopathies, with non-compaction representing a phenotypic variation in patients with DCM- or HCM-causing variants. In contrast, five variant classes were uniquely enriched in LVNC cases, of which truncating variants in MYH7, ACTN2 and PRDM16 may represent a distinct LVNC aetiology. MYH7 truncating variants are generally considered as non-pathogenic but were detected in 2% of LVNC cases compared to 0.1% of controls, including a cluster of variants around a single splice region. Additionally, structural variants (exon deletions) in RYR2 and missense variants in the transmembrane region of HCN4 were enriched in LVNC cases, confirming prior reports regarding the association of these variant classes with combined LVNC and arrhythmia phenotypes.

Conclusions
We demonstrated that genetic association analysis can clarify the relationship between LVNC and established cardiomyopathies, highlighted substantial overlap with DCM/HCM but also identified variant classes associated with distinct LVNC and with joint LVNC/arrhythmia phenotypes. These results underline the complex genetic landscape of LVNC and inform how genetic testing in LVNC cases should be pursued and interpreted.
Cardiomyopathy rare variant frequencies

Funding Acknowledgement
Type of funding source: None
Pharmacological inhibition of C-C chemokine receptor 4 aggravates atherosclerosis through prevention of regulatory T cell recruitment to the lesions
Authors: Amin H , Sasaki N , Horibe S , Kawauchi S , Hirata K , Rikitake Y 
Published: November 2020

Abstract

Background
Regulatory T cells (Tregs) are demonstrated to play a protective role in the development of atherosclerosis. However, their sites of action in atherosclerosis remain unclear. Although C-C chemokine receptor 4 (CCR4) has been shown to contribute to the accumulation of Tregs in inflamed tissues and prevention of experimental autoimmune diseases, the role of CCR4 in Treg migration to atherosclerotic lesions and suppression of plaque formation remains unknown.

Methods and results
We intraperitoneally injected 8-week-old apolipoprotein E–deficient mice fed a normal diet with vehicle (n=9) or a 4-μg dose of a CCR4 antagonist (n=10) 3 times weekly for 8 weeks and evaluated atherosclerotic lesions at 16 weeks old. Administration of the CCR4 antagonist significantly aggravated atherosclerotic plaque formation (aortic sinus plaque area: 2.91±0.87×104 μm2 versus 5.41±0.98×104 μm2 in control vehicle-treated and CCR4 antagonist-treated mice, respectively; P&lt;0.05), associated with increased accumulation of macrophages and CD4+T cells in the plaques. Flow cytometric analysis revealed a decrease in Foxp3+ Tregs in the para-aortic lymph nodes and thoracoabdominal aortas of CCR4 antagonist-treated mice, along with a tendency toward increase in CD44highCD62Lloweffector T cells in para-aortic lymph nodes, indicating CCR4-dependent migration of Tregs to atherosclerotic lesions and their possible atheroprotective role. We observed no changes in splenic Foxp3+ Tregs and effector T cells following CCR4 antagonist treatment. We also investigated the effect of CCR4 blockade on advanced atherosclerosis using LDL receptor–deficient mice fed a high-cholesterol diet. Although 8-week treatment with the CCR4 antagonist led to a decrease in Foxp3+ Tregs in the atherosclerotic lesions, atherosclerotic lesion formation was not significantly affected, suggesting that CCR4-dependent Treg accumulation in atherosclerotic lesions is not critical for prevention of advanced atherosclerosis.

Conclusions
Our findings indicate an important role for CCR4 in promotion of Treg recruitment into atherosclerotic lesions and subsequent prevention of early atherosclerosis and suggest CCR4 as a novel therapeutic target for atherosclerosis.

Funding Acknowledgement
Type of funding source: None
Cardiac fibroblasts acquire properties of matrifibrocytes in vitro and in mice with pressure overload-induced congestive heart failure
Authors: Herum K.M , Gilles G , Romaine A , Melleby A.O , Christensen G , McCulloch A.D , Brakebusch C.H 
Published: November 2020

Abstract

Introduction
Activation of cardiac fibroblasts (CFB) is a key step in development of fibrosis in the heart. It was recently shown that, in addition to the well-studied myofibroblast (myoFB) phenotype, activated cardiac fibroblasts can adopt a newly defined matrifibrocyte phenotype, characterized by expression of extracellular matrix (ECM) genes associated with bone, cartilage and tendon development. However, it is unknown whether matrifibrocytes exists in the pressure-overloaded fibrotic and failing heart, and whether substrate stiffness drives differentiation.

Hypothesis
Matrifibrocyte differentiation occurs in vitro during culturing of primary cardiac fibroblasts, and in vivo in response to left ventricular pressure overload.

Methods
Left ventricular pressure overload induced by o-ring aortic banding (ORAB) induced cardiac phenotypes of concentric hypertrophic remodelling and congestive heart failure. Primary CFB from adult mice were cultured on plastic or soft polyacrylamide hydrogels (4.5 kPa) for various times. mRNA expression of phenotypic markers were measured by RT-PCR. Presence of smooth muscle α-actin (SMA) fibers was determined by immunocytochemistry.

Results
ECM genes normally expressed in bone and cartilage (COMP, CILP-2, OPG and SCX) were upregulated in hypertrophic left ventricles of mice with congestive heart failure. The myoFB marker acta2 was increased 2 weeks after ORAB, returned to baseline at 4 weeks and increased again at 20 weeks when the left ventricle was dilating and failing, indicating that the myoFB phenotype is not permanent. In vitro, primary CFB upregulated bone/cartilage-associated ECM genes after 12 days of culturing on plastic. Acta2 mRNA and SMA protein levels peaked after 9 days in culture whereafter they declined, indicating a shift in phenotype. Culturing primary CFB on soft (4.5 kPa) hydrogels delayed, but did not prevent, myoFB differentiation while expression of bone/cartilage ECM genes was absent or low, indicating that high stiffness is a driver of the matrifibrocyte phenotype. Blockers of mechanotransduction, SB431542 (TGFβRI inhibitor), Y27623 (ROCK inhibitor) and cyclosporine A (calcineurin inhibitor), completely inhibited myoFB differentiation but upregulated several matrifibrocyte markers, indicating that distinct signaling pathways regulate myoFB and matrifibrocyte differentiation. Removing inhibitors re-induced myofibroblast markers in cells on plastic but not on soft gels consistent with high stiffness promoting myofibroblast differentiation.

Conclusion
Primary cardiac fibroblasts acquire characteristics of matrifibrocytes in vitro when cultured for long time on plastic and in vivo in left ventricles of mice with pressure overload-induced congestive heart failure.

Funding Acknowledgement
Type of funding source: Public grant(s) – EU funding. Main funding source(s): Marie Sklodowska-Curie Individual Fellowship
iPSC-derived endothelial cells reflect accelerated senescence and increased inflammatory response in a CVD-risk stratified manner
Authors: Straessler E.T , Kiamehr M , Aalto-Setala K , Kraenkel N.K , Landmesser U.L 
Published: November 2020

Abstract

Background
Cardiovascular disease (CVD) remains the leading cause of death worldwide and its multifactorial nature is recognized, with both an individual's genetic background and lifestyle strongly impacting on its course. On a molecular level, accelerated cellular aging and increased inflammation interact to drive the severity of the disease. We have used patient-derived induced pluripotent stem cells (iPSC) to investigate the impact of a patients' genetic background on (epi-)genetically determined functionality, telomere attrition and inflammatory response.

Purpose
The purpose of this study is to investigate differences on the cellular level between iPSC-derived endothelial cells from risk-stratified CAD patients (both ACS and stable CAD) in both functionality, inflammatory response and ageing rate.

Methods
iPSCs were generated from participants with similar lifestyle but different disease progression (healthy &gt;65 y/o, stable CAD &gt;65 y/o, ACS &lt;65y/o) and differentiated into endothelial cells (iPS-EC). After quality control, iPS-EC were exposed to inflammatory stimulation via TNF-α under static and pro- vs. anti-atherogenic flow conditions (laminar vs. disturbed flow, high vs. low shear stress) and their gene and protein expression of adhesion molecules was assessed by qPCR and flow cytometry. Telomere length was determined by a qPCR-based assay in iPSC-ECs after four (p4) and eleven population doublings [KN1] (p11) in fully supplemented growth medium.

Results
ACS-iPS-ECs showed a significantly stronger upregulation of E-selectin in response to inflammatory stimulation with TNF-a than healthy-iPS-ECs on mRNA level (ACS: 532.1-fold±48.7 vs. healthy: 322.3-fold±55.7, p=0.02). Similarly, ICAM1 protein upregulation was stronger in ACS-iPS-ECs than in healthy iPSC-ECs as assessed by flow cytometry (ACS: 1.4-fold±0.01 vs. healthy: 1.1-fold±0.0007; p&lt;0.001) whereas VCAM1 upregulation was weaker in ACS-iPS-ECs compared to healthy controls (ACS: 1.8-fold±0.3 vs. healthy: 4.2-fold±0.9, p&lt;0.001). Telomere shortening from p4 to p11 was significantly stronger in ACS-iPS-ECs compared to healthy controls (ACS: 35%±10 vs. healthy: 10%±5, p&lt;0.05).

Conclusion
The more pronounced upregulation of specific adhesion molecules (E-Selectin, ICAM-1, but not VCAM-1) in response to inflammatory stimulation together with a stronger telomere attrition in ACS-iPS-EC hints at cells entering faster into a senescent state.

Funding Acknowledgement
Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Research scholarship from the German Society of Cardiology. Allocated research funds from University hospital.
Loss of platelet BMP4 reduces vascular inflammation and ameliorates vascular remodelling after carotid wire injury
Authors: Zhou Q , Jank M , Von Niessen N , Olivier C.B , Schmitt H , Anto-Michel N , Hilgendorf I , Bode C , Moser M 
Published: November 2020

Abstract

Background
Bone morphogenic proteins (BMPs) are members of the TGFβ superfamily. They have distinct functions during hemostasis and play a central role in various pathologic conditions, including cardiovascular diseases. Recent findings demonstrate that BMPs are also expressed in platelets. However, their function is poorly understood. Here, we investigate the role of platelet BMP4 during vascular inflammation and vascular remodelling.

Methods
BMP4 floxed mice were crossed with PF4 Cre mice to generate platelet-specific deletion of BMP4 (BMP4Plt−/−). Intravital microscopy of mesenteric veins was performed to evaluate leukocyte adhesion upon stimulation with TNFα. Expression of adhesion molecules and chemokines were analysed by RT-PCR and Western Blot. P-selectin and platelet-leukocyte aggregates were evaluated using flow cytometry. For carotid wire injury, BMP4Plt−/− were further crossed with LDLr−/− mice (BMP4Plt−/−/LDLr−/−). At 8 weeks of age, BMP4Plt−/−/LDLr−/− mice and control littermates received a 2-week diet containing 15.8% wt/wt fat and 1.25% cholesterol. Carotid wire injury was performed at the age of 10 weeks. Re-endothelialisation and neointimal hyperplasia were evaluated.

Results
Platelet morphology and function did not differ between BMP4Plt−/− and control mice. Stimulation with TNFα resulted in increased rolling and adherence of leukocytes to the vessel wall which was reduced in BMP4Plt−/− mice (175±25 versus 50±7 rolling cells and 16±3 versus 7±2 adherent cells, respectively). Expression of P-selectin, adhesion molecules and the chemokines RANTES and PF-4 were reduced in BMP4Plt−/− mice. Platelet activation by thrombin was reduced in BMP4Plt−/− mice, resulting in diminished P-Selectin and JONA expression. Furthermore, monocyte infiltration and circulating leukocyte-platelet complexes were reduced in BMP4Plt−/− mice. Loss of platelet BMP4 prevented neointima formation after carotid wire injury (4.2x104±0.9x104μm2 versus 14.9x104±2.2x104μm2 in BMP4Plt−/−/LDLr−/− and control mice, respectively). Interestingly, endothelial regeneration after injury was decelerated in BMP4Plt−/− mice. This is further demonstrated in-vitro, where platelet BMP4 promoted endothelial cell proliferation and migration.

Conclusion
Platelet-BMP4 deficiency reduced vascular inflammation and ameliorated intima hyperplasia after wire injury. This is partly mediated by inhibition of platelet activation, reduced expression of adhesion molecules and inflammatory response. Our finding suggests that BMP4 is a promising target for the treatment of vascular inflammation and restenosis.

Funding Acknowledgement
Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Else-Kröner Fresenius Foundation; German Cardiac Society
SDPR/Cavin-2 loss inhibits monocyte adhesion to endothelial cells in abdominal aortic aneurysm via suppressing the expression of adhesion molecules
Authors: Sakamoto A , Ogata T , Nakanishi N , Higuchi Y , Tsuji Y , Tomita S , Matoba S 
Published: November 2020

Abstract

Background
Abdominal aortic aneurysm (AAA) is a common and life-threatening vascular disease. The initial phase of AAA progression is vascular inflammation. Inflammation sites present adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1). These molecules play a crucial role in recruiting inflammatory cells to endothelial cells through NF-κB signaling. Endothelial cells express serum deprivation response (SDPR)/Cavin-2 localized in caveolae on the cell membrane. Although Cavin-2 is involved in such as cell proliferation, migration, and signal transduction, the role of Cavin-2 in vascular inflammation in the development of AAA is still unclear.

Purpose
To assess the influence of Cavin-2 deficiency in AAA development and clarify the role of Cavin-2 in the regulation of inflammatory cell adhesion in endothelial cells.

Methods
CaCl2-induced AAAs were induced by the periaortic application of 0.5 M CaCl2 in male SDPR-knockout (KO) and wild-type (WT) mice at 8–10 weeks of age. Angiotensin II (Ang II)-induced AAAs were created by 4-week-subcutaneous drug infusion in male ApoE-KO and ApoE/Cavin-2-double KO (DKO) mice at 24 weeks of age. Inflammatory response and cell adhesion were evaluated using human aortic endothelial cells (HAECs) and human monocytes (THP-1 cells).

Results
Six weeks after CaCl2 treatment, Cavin-2 deficiency significantly attenuated the development of AAAs. Elastin degradation was markedly suppressed and F4/80-positive macrophages infiltration in aortic walls were decreased in Cavin-2-KO mice. Although Ang II infusion for 4 weeks formed AAAs in ApoE KO mice and ApoE/Cavin-2-DKO mice, ApoE/Cavin-2-DKO mice exhibited the suppression of AAA formation independently of blood pressure. Immunohistochemical staining showed VCAM-1 expression on endothelial cells was suppressed in ApoE/Cavin-2-DKO mice. Further, in vitro co-culture experiment, the number of THP-1 cells adhered to TNF-treated SDPR-knockdown HAECs was decreased compared with that to control HAECs. Moreover, mRNA expression of VCAM-1 and ICAM-1 was decreased in TNFα-treated SDPR-knockdown HAECSs. Protein expression of VCAM-1 was also suppressed in TNFα-treated SDPR-knockdown HAECSs. The activity of NF-κB p65, an upstream regulator of VCAM-1 and ICAM-1,tended to be suppressed in TNFα-treated SDPR-knockdown HAECs.

Conclusion
In this study, we revealed that SDPR/Cavin-2 loss attenuated AAA development with the suppression of elastin degradation and macrophage infiltration. Our findings suggest that SDPR/Cavin-2 in the endothelial cells regulates the expression of adhesion molecules via NF-κB signaling and promotes the adhesion and infiltration of inflammatory cells to the aortic wall.

Funding Acknowledgement
Type of funding source: None