Free-of-Acrylamide SDS-based Tissue Clearing (FASTClear) for three dimensional visualization of myocardial tissue

AbstractSeveral pathologic conditions of the heart lead to cardiac structural remodelling. Given the high density and the opaque nature of the myocardium, deep three dimensional (3D) imaging is difficult to achieve and structural analysis of pathological myocardial structure is often limited to two dimensional images and of thin myocardial sections. Efficient methods to obtain optical clearing of the tissue for 3D visualisation are therefore needed. Here we describe a rapid, simple and versatile Free-of-Acrylamide SDS-based Tissue Clearing (FASTClear) protocol specifically designed for cardiac tissue. With this method 3D information regarding collagen content, collagen localization and distribution could be easily obtained across a whole 300 µm-thick myocardial slice. FASTClear does not induce structural or microstructural distortion and it can be combined with immunostaining to identify the micro- and macrovascular networks. In summary, we have obtained decolorized myocardial tissue suitable for high resolution 3D imaging, with implications for the study of complex cardiac tissue structure and its changes during pathology.</jats:p

Preconditioning of Cardiosphere-Derived Cells With Hypoxia or Prolyl-4-Hydroxylase Inhibitors Increases Stemness and Decreases Reliance on Oxidative Metabolism

Cardiosphere-derived cells (CDCs), which can be isolated from heart explants, are a promising candidate cell source for infarcted myocardium regeneration. However, current protocols used to expand CDCs require at least 1 month in vitro to obtain sufficient cells for transplantation. We report that CDC culture can be optimized by preconditioning the cells under hypoxia (2% oxygen), which may reflect the physiological oxygen level of the stem cell niche. Under hypoxia, the CDC proliferation rate increased by 1.4-fold, generating 6 × 10(6) CDCs with higher expression of cardiac stem cell and pluripotency gene markers compared to normoxia. Furthermore, telomerase (TERT), cytokines/ligands involved in stem cell trafficking (SDF/CXCR-4), erythropoiesis (EPO), and angiogenesis (VEGF) were increased under hypoxia. Hypoxic preconditioning was mimicked by treatment with two types of hypoxia-inducible factor (HIF) prolyl-4-hydroxylase inhibitors (PHDIs): dimethyloxaloylglycine (DMOG) and 2-(1-chloro-4-hydroxyisoquinoline-3-carboxamido) acetic acid (BIC). Despite the difference in specificity, both PHDIs significantly increased c-Kit expression and activated HIF, EPO, and CXCR-4. Furthermore, treatment with PHDIs for 24 h increased cell proliferation. Notably, all hypoxic and PHDI-preconditioned CDCs had decreased oxygen consumption and increased glycolytic metabolism. In conclusion, cells cultured under hypoxia could have potentially enhanced therapeutic potential, which can be mimicked, in part, by PHDIs

Intact myocardial preparations reveal intrinsic transmural heterogeneity in cardiac mechanics

Determining transmural mechanical properties in the heart provides a foundation to understand physiological and pathophysiological cardiac mechanics. Although work on mechanical characterisation has begun in isolated cells and permeabilised samples, the mechanical profile of living individual cardiac layers has not been examined. Myocardial slices are 300 μm-thin sections of heart tissue with preserved cellular stoichiometry, extracellular matrix, and structural architecture. This allows for cardiac mechanics assays in the context of an intact in vitro organotypic preparation. In slices obtained from the subendocardium, midmyocardium and subepicardium of rats, a distinct pattern in transmural contractility is found that is different from that observed in other models. Slices from the epicardium and midmyocardium had a higher active tension and passive tension than the endocardium upon stretch. Differences in total myocyte area coverage, and aspect ratio between layers underlined the functional readouts, while no differences were found in total sarcomeric protein and phosphoprotein between layers. Such intrinsic heterogeneity may orchestrate the normal pumping of the heart in the presence of transmural strain and sarcomere length gradients in the in vivo heart

Role of blood cells dynamism on hemostatic complications in low-risk patients with essential thrombocythemia

Patients with essential thrombocythemia (ET) aged less than 60 years, who have not suffered a previous vascular event (low-risk patients), may develop thrombotic or hemorrhagic events. So far, it has not been possible to identify useful markers capable of predicting which of these patients are more likely to develop an event and therefore who needs to be treated. In the present study, we analysed the relationship between vascular complications and longitudinal blood counts of 136 low-risk ET patients taken over a sustained period of time (blood cells dynamism). After a median follow-up of 60 months, 45 out of 136 patients (33%) suffered 40 major thrombotic and 5 severe hemorrhagic complications. A total number of 5,781 blood counts were collected longitudinally. Thrombotic and hemorrhagic events were studied together (primary endpoint) but also separately (thrombotic alone = secondary endpoint; hemorrhagic alone = tertiary endpoint). The primary endpoint showed no significant association between platelet and WBC count at diagnosis and risk of any event (platelet, p = 0.797; WBC, p = 0.178), while Hb at baseline did show an association (p = 0.024). In the dynamic analysis with Cox regression model, where the blood count values were studied by time of follow-up, we observed that the risk for Hb was 1.49 (95% CI 1.13-1.97) for every increase of 1 g/dL, and that this risk then marginally decreased during follow-up. WBC was associated with an increased risk at baseline for every increase of 1 7 10(9)/L (hazard ratio (HR) 1.07, 95% CI 1.01-1.13, p = 0.034), the risk was stable during follow-up (HR 0.95, p = 0.187 at 60 months). Also, for each increment at baseline of 100 7 10(9) platelets/L, HR was increased by 1.08 (95% CI 0.97-1.22, p = 0.159) and decreases during follow-up. In conclusion, this study is the first to evaluate in ET low-risk patients, the risk of developing a thrombotic/hemorrhagic event considering blood counts over time. Overall our study shows that the risk changes over time. For example, the risk associated with WCC is not linear as previously reported. An interesting new finding is that PLT and even Hb contribute to the risk of developing vascular events. Future treatments should take into consideration these findings and aim to control all parameters over time. We believe this early study may help develop a dynamic analysis model to predict thrombosis in the single patient. Further studies are now warranted to further validate our findings

Adipose and cardiac progenitor cells for regenerative medicine

Le malattie cardiovascolari e il loro evoluzione in arresto cardiaco, sono una della principali cause di morte a livello mondiale. Il diabete \ue8 spesso associato all'alterazione dei substrati metabolici i quali sono in grado di modificare l'omeostasi dei tessuti ed alterare le popolazioni di precursori cellulari. La maggior parte dei tessuti adulti presenta delle sotto-popolazioni di progenitori mesenchimali che, a causa delle loro propriet\ue0 rigenerative, sono un'interessante fonte di cellule per la medicina rigenerativa e la terapia cellulare. Recentemente \ue8 stato dimostrato che, in seguito ad un arresto cardiaco, l'iniezione di cellule mesenchimali pu\uf2 migliorare la contrattilit\ue0 cardiaca in topo e ratto. Lo scopo di questa tesi \ue8 stato di isolare, caratterizzare e differenziare cellule mesenchimali di tessuto adiposo (ADMSCs) e cellule derivate da cardiosfere (CDCs) e determinare l'effetto di una dieta ad alto contenuto di grassi su queste due popolazioni cellulari. Da tessuto atriale di topo sono state isolate EDCs (Explant-derived cells) e CDCs, mentre dal tessuto adiposo inguinale, dopo digestione con collagenasi di tipo2, sono state isolate ADMSCs. Quest'ultime, dopo espansione in vitro, contengono un numero maggiore di cellule CD90+ (47% vs 87%) e minore di DDR2+ and CD45 rispetto a cellule appena isolate (rispettivamente 9% e 20% vs 38% e 42%). Alcuni medium sono stati testati per verificare la capacit\ue0 differenziativa delle ADMSCs, di questi solo il medium con TGF\u3b2 \ue8 stato in grado di aumentare l espressione di geni cardiaci. L'espansione di ADMSCs in ipossia ha aumentato la velocit\ue0 di proliferazione e ha modificato il profilo di marker cellulari espresso dalle ADMSCs. E' stato inoltre notato un numero pi\uf9 elevato di cellule positive per DDR2 e minore di CD45+ e CD90+ rispetto a ADMSCs espanse in normali condizioni di ossigeno. L'espansione di fibroblasti cardiaci in vitro e CDCs ha rivelato una similarit\ue0 tra queste due popolazioni, entrambe aumentano la velocit\ue0 di proliferazion e la capacit\ue0 clonogenica con l'aumentare dei passaggi in cultura ed esprimono marker mesenchymali e marker espressi da fibroblasti come CD90 e DDR2. Le CDCs hanno dimostrato di essere in grado di acquisire un fenotipo cardiaco in vitro, aumentando l'espressione di cardiac actin e troponin T, tuttavia non sono state osservate cellule con spontanea attivit\ue0 contrattile. Dopo quattro mesi di dieta ad alto contentuto di grassi (55% grasso, HFD) i topi presentano aumentati livelli plasmatici di glucosio, colesterolo e insulina e diminuiti livelli di lattato. Un numero significativamente maggiore di ADMSCs sono stae isolate da animali HFD e il numero di ADMSCs correla con i livelli pasmatici di glucosio, colesterolo e lattato. I livelli di espressione di CD45, DDR2 e CD105 sono aumentati in ADMSCS da topi con dieta ad alto contenuto di grassi e la loro funzionalit\ue0 e capacit\ue0 differenziativa \ue8 risultata essere leggermente diminuita. Nelle CDCs non sono state riscontrate differenze n\ue8 nell'espressione di marker n\ue8 nella loro funzionalit\ue0. Per concludere, 4 mesi di dieta HFD sono in grado di indurre un fenotipo diabetico in topi C57 Black 6. La dieta HFD ha aumentato il numero di ADMSCs ma ha modificato le percentuali di sottopopolazioni all interno di questa popolazione, inoltre \ue8 stata registrata un diminuzione nella loro capacit\ue0 differenziativa. Al contrario, le CDCs non sono state influenzate dal fenotipo diabetico.Cardiovascular diseases, and the progression to heart failure, are one of the leading cause of death. Diabetes is often associate with cardiovascular complications because of the disturbed substrate metabolism that can alter the homeostasis of the tissues and modify the progenitor cell populations. Most adult tissues have a mesenchymal progenitor cell subpopulation that represents a proportion of the total cell number and which, because of its regenerative properties, is an attractive source for cell therapy. Recently it has been proved that injection of mesenchymal cells improve contractile function in rodents following myocardial infarction. The aim of this study was to isolate, characterize and differentiate adipose-derived mesenchymal stem cells (ADMSCs), and cardiosphere-derived cells (CDCs), and to determine the effect of simply a high fat diet on these two mesenchymal populations. Cardiac explant-derived and cardiosphere-derived cells (EDCs, CDCs) were cultured from atrial tissue and adipose stem cells were cultured from epididymal fat depots after collagenase digestion. Cultured ADMSCs contained more CD90+ cells (47% vs 87%) and fewer DDR2+ and CD45+ cells compared to freshly isolated ADMSCs (respectively 9% and 20% vs 38% and 42%). Various media were tested to validate the differentiation capacity of adipose mesenchymal cells, but only the TGF\u3b2-supplemented medium was able to increase the expression of cardiac specific genes. Hypoxia increased cell proliferation and changed the surface marker profile of ADMSCs; more DDR2+ cells and fewer CD45+ and CD90+ cells were found compared to normoxic ADMSCs. In vitro expansion of neonatal cardiac fibroblasts and cardiosphere-derived cells revealed a similarity between these two cell populations, both increased proliferation and clonogenic capacity with time in culture and expressed mesenchymal/fibroblast markers such as CD90 and DDR2. CDCs were able to acquire a cardiac phenotype in vitro, increasing gene expression of cardiac actin and troponin T, however no beating cells were observed. After 4 months of high-fat diet (55% fat; HFD,) mice had raised fed plasma glucose, cholesterol and insulin levels and decreased plasma lactate. Significantly more ADMSCs were obtained from high fat fed animals and ADMSC numbers correlated with plasma glucose, cholesterol and lactate. Expression of CD45, DDR2 and CD105 were increased in ADMSCs from high fat fed mice and the functional properties and differentiation capacity were slightly decreased. No differences in surface marker expression and functional properties were detected between high fat and chow diet mice CDCs. In conclusion, four months of HFD induced a diabetic phenotype in C57 Black 6 mice. The high fat diet increased ADMSCs yield but modified the balance of ADMSCs populations and decreased their differentiation capacity. In contrast, cardiac progenitor cells were unaffected by induction of the diabetic phenotype

Non-coding RNAs: emerging players in cardiomyocyte proliferation and cardiac regeneration

Soon after birth, the regenerative capacity of the mammalian heart is lost, cardiomyocytes withdraw from the cell cycle and demonstrate a minimal proliferation rate. Despite improved treatment and reperfusion strategies, the uncompensated cardiomyocyte loss during injury and disease results in cardiac remodeling and subsequent heart failure. The promising field of regenerative medicine aims to restore both the structure and function of damaged tissue through modulation of cellular processes and regulatory mechanisms involved in cardiac cell cycle arrest to boost cardiomyocyte proliferation. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) are functional RNA molecules with no protein-coding function that have been reported to engage in cardiac regeneration and repair. In this review, we summarize the current understanding of both the biological functions and molecular mechanisms of ncRNAs involved in cardiomyocyte proliferation. Furthermore, we discuss their impact on the structure and contractile function of the heart in health and disease and their application for therapeutic interventions

A practical guide for investigating cardiac physiology using living myocardial slices

Ex vivo multicellular preparations are essential tools to study tissue physiology. Among them, the recent methodological and technological developments in living myocardial slices (LMS) are attracting increasing interest by the cardiac research field. Despite this, this research model remains poorly perceived and utilized by most research laboratories. Here, we provide a practical guide on how to use LMS to interrogate multiple aspects of cardiac function, structure and biochemistry. We discuss issues that should be considered to conduct successful experiments, including experimental design, sample preparation, data collection and analysis. We describe how laboratory setups can be adapted to accommodate and interrogate this multicellular research model. These adaptations can often be achieved at a reasonable cost with off-the-shelf components and operated reliably using well-established protocols and freely available software, which is essential to broaden the utilization of this method. We will also highlight how current measurements can be improved to further enhance data quality and reliability to ensure inter-laboratory reproducibility. Finally, we summarize the most promising biomedical applications and envision how living myocardial slices can lead to further breakthroughs

Resident cardiac macrophages: crucial modulators of cardiac (patho)physiology

Resident cardiac macrophages (rcMacs) are integral components of the myocardium where they have key roles for tissue homeostasis and in response to inflammation, tissue injury and remodelling. In this review, we summarize the current knowledge and limitations associated with the rcMacs studies. We describe their specific role and contribution in various processes such as electrical conduction, efferocytosis, inflammation, tissue development, remodelling and regeneration in both the healthy and the disease state. We also outline research challenges and technical complications associated with rcMac research. Recent technological developments and contemporary immunological techniques are now offering new opportunities to investigate the separate contribution of rcMac in respect to recruited monocytes and other cardiac cells. Finally, we discuss new therapeutic strategies, such as drugs or non-coding RNAs, which can influence rcMac phenotype and their response to inflammation. These novel approaches will allow for a deeper understanding of this cardiac endogenous cell type and might lead to the development of more specific and effective therapeutic strategies to boost the heart's intrinsic reparative capacity

Immunomodulation after radiofrequency ablation of locally advanced pancreatic cancer by monitoring the immune response in 10 patients

Objective/Background: RFA of pancreatic cancer has been demonstrated to be feasible and safe with a positive impact on survival. The aim was to investigate whether an immune reaction is activated after locally advanced pancreatic cancer (LAPC) ablation.Methods: Peripheral Blood samples were obtained preoperatively and on post-operative days 3-30. Evaluated parameters were: cells [CD4+, CD8+ and activated subsets, T-Reg, Monocytes, myeloid and plasmocytoid Dendritic cells (mDC and pDC)] and cytokines [Interleukin (IL)-6, Stromal-cells derived factor (SDF)-1, IL-1 beta, Tumour-Necrosis Factor (TNF)-alpha, Interferon (IFN)-gamma, Vascular Endothelial Growth Factor (VEGF), chemokine (C-C motif) ligand 5 (CCL-5), Transforming-Growth Factor (TGF)-beta].Results: Ten patients were enrolled. CD4+, CD8+ and TEM increased from day 3 suggesting the activation of the adaptive response. Immunosuppressive T-Reg cells were stable despite the possibility that laparotomy and heating might favour their expansion. Myeloid DCs, that present tumour-associated antigens, increased at day 30. RFA dramatically increased circulating IL-6 at day 3 but this decreased to baseline by day 30, consistent with the supposed anti-tumour effect. RFA did not significantly modulate essential chemokines, such as CCL-5 and SDF1, VEGF, TGF-beta and TNF-alpha, that favour tumour-growth by sustaining cancer angiogenesis and fuelling tumour-associated inflammation.Conclusions: This study provides the first evidence of RFA-based immunomodulation in LAPC. We observed a general activation of adaptive response along with a decrease of immunosuppression. Furthermore, most cells showed prolonged activation some weeks after the procedure, suggesting true immunomodulation rather than a normal inflammatory response. (C) 2017 IAP and EPC. Published by Elsevier B.V. All rights reserved