Aim of this study was to provide an echocardiographic protocol for the description of the normal murine venous reservoir (atrium, appendage and pulmonary veins) and to investigate the possibility to use this approach to discriminate changes on left atrium (LA) and left atrial appendage (LAA) in a stress-induced model such us myocardial infarction. Global left ventricular function and the venous reservoir were assessed by a Vevo2100 in 20 female C57BL/6N. LA and LAA were also studied in 10 CD-1 and 10 FVB mice, whereas modifications investigated in 15 C57BL/6N subjected to coronary artery ligation. Left ventricle function was evaluated as well as pulsed Doppler mitral valve, pulmonary vein, and LAA velocities. From 2D view monoplane LA volumes were obtained and LAA long axis measured. Macroscopic inspection with casts and immunohistochemistry were performed. Results show that compared to humans, in C57BL/6N mice left atrium was disproportionately smaller (5.2±1.4μL) than the left ventricle (53±8μL) and connected through a duct by a large LAA and posteriorly to three pulmonary veins. The LA volume increased 2-fold during reservoir with two distinct phases, early and late divided by a short pause. LAA long axis (4.1±0.5mm) was almost 2 times longer than the LA. LAA flow volume together with LA volume reservoir account for about 36% of stroke volume and the rest was provided by conduit flow. Linear regressions showed that stroke volume was strongly influenced by LAA flow, LA early filling volume and left ventricle base descent. Moreover, we also report the ability to assess LA and LAA in other mice strains and discriminate size increase following myocardial infarction. In conclusion, we performed a complete characterization of murine left venous reservoir establishing an optimized protocol that can be used in both investigative and pharmacological studies requiring rapid and serial determination of cardiac structure and function.
Purpose: Cardiac deformation imaging techniques have been used to assess the local effects of cardiac regeneration therapy.Limited spatial and temporal resolution of clinically available techniques prevents detailed analysis of local myocardial deformation.Other imaging techniques might be more appropriate to assess local therapeutic effects.We used radio-frequency (RF) ultrasound to estimate local radial strain.To confirm the results analytically, we used an ellipsoidal geometrical model of the left ventricle.Methods: Data acquisition was done epicardially in 5 pigs.RF ultrasound data were acquired using a Medison Accuvix V10 with an RF interface.Data acquisition was done at 129 fps, using an L5-13 linear array transducer (center frequency = 8.5 MHz).Parameters for the analytical radial strain solution were (see figure): end diastolic outer radius (Rod = 3.5cm), end diastolic inner radius (Rid = 2.5cm), end diastolic length (Ld = 9cm), end systolic outer radius change 25%, end systolic length change 223%.Results: RF based radial strain estimation shows a transmural gradient of peak radial strain from sub-endocard to sub-epicard from 72% to 34%.The analytical solution resulted in reasonable hemodynamic parameters: EDV = 117ml, ESV = 47ml and EF = 59%.Systolic radial strain of the analytical solution was in the same range as the peak radial strain in the experiments and ranged from 80% to 36%.Conclusion: By using a geometric model based on parameters deduced from the experiments, and the assumption that cardiac tissue is incompressible, peak radial strain values in different layers of the myocardium found by RF ultrasound analysis could be confirmed analytically.We hereby show analytically and experimentally that sub-endocardial peak radial strain values can be as high as 80 to 90%.
Herein we combine chemical and mechanical stimulation to investigate the effects of vascular endothelial growth factor (VEGF) and physiological shear stress in promoting the differentiation human adipose derived stem cells (ADSCs) into endothelial cells. ADSCs were isolated and characterized; endothelial differentiation was promoted by culturing confluent cells in 50 ng/ml VEGF under physiological shear stress for up to 14 days. Afterwards, endothelial cells were seeded onto collagen or acellular aortic valve matrices and exposed to four culture conditions: shear stress + VEGF; shear stress − VEGF; static + VEGF and static − VEGF. After 7 days, phenotype was investigated. ADSCs subjected to shear stress and VEGF express a comprehensive range of specific endothelial markers (vWF, eNOS and FLT-1 after 7 days and CD31, FLk-1 and VE-cadherin after 14 days) and maintain the phenotype when seeded onto scaffolds. Our protocol proved to be an efficient source of endothelial-like cells for tissue engineering based on autologous ADSC.
Cysteinyl leukotrienes (CysLTs) are potent lipid mediators widely known for their actions in asthma and in allergic rhinitis. Accumulating data highlights their involvement in a broader range of inflammation-associated diseases such as cancer, atopic dermatitis, rheumatoid arthritis, and cardiovascular diseases. The reported elevated levels of CysLTs in acute and chronic brain lesions, the association between the genetic polymorphisms in the LTs biosynthesis pathways and the risk of cerebral pathological events, and the evidence from animal models link also CysLTs and brain diseases. This review will give an overview of how far research has gone into the evaluation of the role of CysLTs in the most prevalent neurodegenerative disorders (ischemia, Alzheimer’s and Parkinson’s diseases, multiple sclerosis/experimental autoimmune encephalomyelitis, and epilepsy) in order to understand the underlying mechanism by which they might be central in the disease progression.
Background - GPR17 is a G i -coupled dual receptor activated by uracil-nucleotides and cysteinyl-leukotrienes, families of signaling molecules massively released into hypoxic tissues. In the normal heart GPR17 expression has been reported, while its role during ischemia is totally unknown. Aims and Results - To investigate GPR17 expression in mice hearts, before or after myocardial infarction (MI) induction, immunofluorescence was set up. In non ischemic hearts, GPR17 protein was confined into small cell groups localized between myocytes. These cells expressed the stem cell antigen-1 (Sca-1). At 24, 48 and 72 hrs post-MI, cell clusters expressing GPR17 were found to infiltrate the MI border zone and penetrate into the ischemic area. They expressed Sca-1, the myofibroblast/mesenchymal marker CD44 and the hematopoietic lineage marker CD45. Interestingly, not all cells expressing GPR17 also expressed CD45, suggesting a dual origin of GPR17 + cells recruited after MI. A flow-sorting experiment was performed to separate Sca-1 + /CD45 + from Sca-1 + /CD45 - cells at 48 hrs post-MI. RT-PCR showed that both cellular populations expressed GPR17, thus confirming their dual origin. A clonogenic Sca-1 + cell line was derived from non-ischemic hearts. In addition to CD44, these cells expressed mesenchymal markers CD29 and CD105, but not endothelial and hematopoietic markers, and showed a side population phenotype. Sca-1 + cells expressed GPR17 RNA/protein and were able to differentiate into cardiac lineage cells and myofibroblasts in culture. To investigate GPR17 functions, Sca-1 + cells were treated with receptor agonists UDP-Glucose (10nM) and LTD 4 (100nM). These ligands did not rescue cells from hypoxia-induced apoptosis. By contrast, they enhanced CSCs migratory activity (3.1±0.8 and 1.7±0.2, folds vs. control; P < .05 paired t-test). Finally, addition of GPR17 antagonists montelukast and cangrelor abolished this migratory effect. Conclusions - The present results indicate a role of dual GPR17 receptor in early homing of Sca-1 + cardiac stem cells-derived and circulatory stem cells-derived myofibroblasts into the infarcted myocardium. These findings have implications for the pharmacologic control of heart remodeling at early times after infarction.
Cysteinyl leukotrienes (CysLTs) are potent lipid inflammatory mediators synthesized from arachidonic acid, through the 5-lipoxygenase (5-LO) pathway. Owing to their properties, CysLTs play a crucial role in the pathogenesis of inflammation; therefore, CysLT modifiers as synthesis inhibitors or receptor antagonists, central in asthma management, may become a potential target for the treatment of other inflammatory diseases such as the cardiovascular disorders. 5-LO pathway activation and increased expression of its mediators and receptors are found in cardiovascular diseases. Moreover, the cardioprotective effects observed by using CysLT modifiers are promising and contribute to elucidate the link between CysLTs and cardiovascular disease. The aim of this review is to summarize the state of present research about the role of the CysLTs in the pathogenesis and progression of atherosclerosis and myocardial infarction.
Valve interstitial cells populate aortic valve cusps and have been implicated in aortic valve calcification. Here we investigate a common in vitro model for aortic valve calcification by characterizing nodule formation in porcine aortic valve interstitial cells (PAVICs) cultured in osteogenic (OST) medium supplemented with transforming growth factor beta 1 (TGF-β1). Using a combination of materials science and biological techniques, we investigate the relevance of PAVICs nodules in modeling the mineralised material produced in calcified aortic valve disease. PAVICs were grown in OST medium supplemented with TGF-β1 (OST+TGF-β1) or basal (CTL) medium for up to 21 days. Murine calvarial osteoblasts (MOBs) were grown in OST medium for 28 days as a known mineralizing model for comparison. PAVICs grown in OST+TGF-β1 produced nodular structures staining positive for calcium content; however, micro-Raman spectroscopy allowed live, noninvasive imaging that showed an absence of mineralized material, which was readily identified in nodules formed by MOBs and has been identified in human valves. Gene expression analysis, immunostaining, and transmission electron microscopy imaging revealed that PAVICs grown in OST+TGF-β1 medium produced abundant extracellular matrix via the upregulation of the gene for Type I Collagen. PAVICs, nevertheless, did not appear to further transdifferentiate to osteoblasts. Our results demonstrate that 'calcified' nodules formed from PAVICs grown in OST+TGF-β1 medium do not mineralize after 21 days in culture, but rather they express a myofibroblast-like phenotype and produce a collagen-rich extracellular matrix. This study clarifies further the role of PAVICs as a model of calcification of the human aortic valve.
Aim Left ventricle (LV) regional fractional area change (RFAC) measured by cardiac magnetic resonance (CMR) allows the non-invasive localization and quantification of the degree of myocardial infarction (MI), and could be applied to assess the effectiveness of pharmacological or regenerative therapies. Here we investigate the ability of RFAC to identify regional dysfunction and discriminate the effect of pharmacological treatment with valsartan, a selective antagonist of angiotensin II type 1 receptor, in a model of MI. Methods and Results C57BL/6N mice, undergoing coronary artery ligation, were divided into two groups: untreated (MI) or treated with valsartan (MI+Val). Sham-operated mice were used as a control. Cardiac dimensions and function were assessed at baseline, 24 hours, 1 and 4 weeks post surgery by CMR and echocardiography. At sacrifice histology and whole-genome gene expression profiling were performed. RFAC was able to detect significant differences between treatment groups whereas the global ejection fraction was not. RFAC showed greater loss of regional contraction in remote non-infarcted myocardium in MI group than in MI+Val group. Consistently, in the same region MI+Val mice showed reduced myocyte hypertrophy, fibroblast proliferation, and fibrosis and modulation of target genes; in addition, left atrium volumes, appendage length and duct contraction were preserved. Conclusion In this study, RFAC effectively estimated the degree of systolic dysfunction and discriminated the regions preserved by pharmacological treatment. RFAC index is a promising tool to monitor changes in LV contraction and to assess the effectiveness of therapeutic regimens in clinical settings.
Prevention of cardiovascular disease (CVD) is of key importance in reducing morbidity, disability and mortality worldwide. Observational studies suggest that digital health interventions can be an effective strategy to reduce cardiovascular (CV) risk. However, evidence from large randomised clinical trials is lacking.The CV-PREVITAL study is a multicentre, prospective, randomised, controlled, open-label interventional trial designed to compare the effectiveness of an educational and motivational mobile health (mHealth) intervention versus usual care in reducing CV risk. The intervention aims at improving diet, physical activity, sleep quality, psycho-behavioural aspects, as well as promoting smoking cessation and adherence to pharmacological treatment for CV risk factors. The trial aims to enrol approximately 80 000 subjects without overt CVDs referring to general practitioners' offices, community pharmacies or clinics of Scientific Institute for Research, Hospitalization and Health Care (Italian acronym IRCCS) affiliated with the Italian Cardiology Network. All participants are evaluated at baseline and after 12 months to assess the effectiveness of the intervention on short-term endpoints, namely improvement in CV risk score and reduction of major CV risk factors. Beyond the funded life of the study, a long-term (7 years) follow-up is also planned to assess the effectiveness of the intervention on the incidence of major adverse CV events. A series of ancillary studies designed to evaluate the effect of the mHealth intervention on additional risk biomarkers are also performed.This study received ethics approval from the ethics committee of the coordinating centre (Monzino Cardiology Center; R1256/20-CCM 1319) and from all other relevant IRBs and ethics committees. Findings are disseminated through scientific meetings and peer-reviewed journals and via social media. Partners are informed about the study's course and findings through regular meetings.NCT05339841.
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