Extracellular vesicles from human cardiac progenitor cells inhibit cardiomyocyte apoptosis and improve cardiac function after myocardial infarction

Aims Recent evidence suggests that cardiac progenitor cells (CPCs) may improve cardiac function after injury. The underlying mechanisms are indirect, but their mediators remain unidentified. Exosomes and other secreted membrane vesicles, hereafter collectively referred to as extracellular vesicles (EVs), act as paracrine signalling mediators. Here, we report that EVs secreted by human CPCs are crucial cardioprotective agents. Methods and results CPCs were derived from atrial appendage explants from patients who underwent heart valve surgery. CPC-conditioned medium (CM) inhibited apoptosis in mouse HL-1 cardiomyocytic cells, while enhancing tube formation in human umbilical vein endothelial cells. These effects were abrogated by depleting CM of EVs. They were reproduced by EVs secreted by CPCs, but not by those secreted by human dermal fibroblasts. Transmission electron microscopy and nanoparticle tracking analysis showed most EVs to be 30-90 nm in diameter, the size of exosomes, although smaller and larger vesicles were also present. MicroRNAs most highly enriched in EVs secreted by CPCs compared with fibroblasts included miR-210, miR-132, and miR-146a-3p. miR-210 down-regulated its known targets, ephrin A3 and PTP1b, inhibiting apoptosis in cardiomyocytic cells. miR-132 down-regulated its target, RasGAP-p120, enhancing tube formation in endothelial cells. Infarcted hearts injected with EVs from CPCs, but not from fibroblasts, exhibited less cardiomyocyte apoptosis, enhanced angiogenesis, and improved LV ejection fraction (0.8 ± 6.8 vs. −21.3 ± 4.5%; P < 0.05) compared with those injected with control medium. Conclusion EVs are the active component of the paracrine secretion by human CPCs. As a cell-free approach, EVs could circumvent many of the limitations of cell transplantatio

Tension–shear interaction domain for EVA-laminated countersunk point-fixing devices

The present paper aims is to characterize the mechanical behavior of a new embedded point-fixing device for laminated glass for combined tension-shear load cases. This kind of support is based on the principle known as "interlayer junction" in which the anchor is bonded to the interlayer and embedded in the glass panes during the lamination process. The purposes of this innovative point-fixing device are nowadays mainly focused on interior architecture applications: e.g. balustrades, stairs, doors, elevator cars and wells, design furniture, etc., taking advantage of the beautiful aesthetic of an "all-glass" element. This is due to the fact that, contrary to traditional point-fixing bolted connections, the countersunk hole is not passing through the outer glass layer, so that the stainless steel anchor looks like embedded in the glass mass. A comprehensive experimental investigation on the load-bearing capacity under the combined action of tension and shear forces is performed by means of specifically designed test apparatus and procedure. The failure modes in the different direction of load applications are identified and discussed. Finally, in addition to the interaction domain given for combined load cases between tension and shear forces, a simplified analytical interaction expression is also proposed, intended to be used in the practical design applications

EXTERNAL FRP REINFORCEMENT OF DOUGLAS FIR BEAMS IN BENDING

The use of bonded Fiber Reinforced Polymer laminates for strengthening solid wood structural members is receiving increasing attention in recent years, especially for structural rehabilitation purposes, where existing solid members may present natural defects, significant inclination of the grain direction and initial cracking. The paper experimentally investigates the bending strengthening of solid Douglas Fir beams, with axis parallel or inclined to the grain direction, through the application of a Carbon Fiber Reinforced Polymer glued by an epoxy resin on the tension side of the beams only. Reinforcement thickness, presence and position of steel reinforcement in compression are also accounted as additional parameters. Finally, some beams were loaded till cracking, successively reinforced and re-loaded till failure to assess the effects of the reinforcement on a significantly damaged element. The increment in bending performances due to the application of CFRP is discussed, as well as the effectiveness of the addition of the metal reinforcement, also depending on the initial damage level of the beam. To the structural rehabilitation purposes, it is shown how large variations in mechanical performances of timber elements, due to natural defects of woods or to inclination of the grain direction, may be reduced by the introduction of the CFRP reinforcement

Exosomes from Human Cardiac Progenitor Cells Preserve Cardiac Function Long Term after Myocardial Infarction

Introduction: Recent evidence suggests cardiac progenitor cells (CPC) may improve cardiac function after injury. The underlying mechanisms are indirect, but their mediators remain unidentified. Exosomes (Exo) act as paracrine signalling mediators. Here we report that Exo secreted by human CPC are crucial cardioprotective agents that improve left ventricular ejection fraction (LVEF %) in long term animal model of infarct. Methods: Medium from CPC or normal human dermal fibroblasts (NHDF) was conditioned for 5-7 days and subjected to differential centrifugation for Exo isolation. Exo from CPC (Exo-CPC) were tested in-vitro for their functional activity such as anti-apoptotic and pro-angiogenic effects and compared with Exo from NHDF (Exo-F). The content of micro-RNA (miRNA) has been analysed by real-time PCR in Exo-CPC vs Exo-F. Exo-CPC derived from six patients were pooled and intramyocardially injected in-vivo in animal model of permanent left anterior descending (LAD) coronary ligation. One and four weeks after injection LVEF was evaluated by echocardiography and hearts were processed for histological analysis. Results: Exo-CPC inhibited apoptosis in cardiomyocytes, while enhancing tube formation in human endothelial cells invitro compared to Exo-F. Exo-CPC were enriched in miR-210, miR-132, miR-146a, and miR-181a compared to Exo-F. In gain-of-function studies, miR-210 and miR-146a inhibited apoptosis in cardiomyocytes by downregulating their targets ephrinA3/PTP1b and Nox4 respectively. miR-132 downregulated its target RasGAP-p120 and enhanced angiogenesis. Moreover, Exo-CPC, but not Exo-F, downregulated anti-apoptotic factors in cardiomyocytes. Infarcted hearts injected with Exo-CPC significantly preserved the LVEF after one week (84.00±1.6%) and the effect was preserved after four weeks (80.57±2.3%) compared with animals injected with Exo-F (60.71±7.4%; 48.00±4.6% one and four weeks respectively). Moreover Exo-CPC injected hearts showed significantly reduced scar size (6.7±2.0% Exo-CPC vs 19.25±3.4% Exo-F). Summary/Conclusion: Exo are the active component of the paracrine secretion of human CPC. They are enriched in miRNA with cardioprotective and proangiogenic activities. Exo-CPC preserve heart function in a long term animal model of permanent LAD ligation. As a cell-free approach, Exo could circumvent many of the limitations of cell transplantation

Exosomes from human cardiac progenitor cells, but not those from patient-matched bone marrow-derived mesenchymal stem cells,improve cardiac function after myocardial infarction in vivo

Background: Both human cardiac progenitor cells (CPC) and bone marrow-derived mesenchymal stem cells (MSC) have been tested in clinical trials of cell transplantation in patients with myocardial infarction (MI). We have recently shown that Exosomes (secreted nanovesicles; Exo) from CPC account for cardioprotective and proangiogenic activities of these cells both in vitro and in vivo. This study aimed to compare Exo-CPC and Exo-MSC in terms of cardioprotective effects and functional improvement after MI. The role of microRNA (miRNA) and ischemic preconditioning (IPC) were assessed. Methods: CPC and MSC were derived from right atrial appendage and bone aspirate from patients undergoing heart valve surgery. Samples from both tissues were obtained for a patient-matched comparison of Exo from the two cell lines. Exo were isolated by differential ultracentrifugation of conditioned media from CPC or MSC. Anti-apoptotic and proangiogenic effects of Exo-CPC and Exo-MSC were assessed in vitro and compared with Exo from human dermal fibroblast cell line (Exo-F). IPC was performed by subjecting CPC or MSC to two short rounds of hypoxia and glucose deprivation. miRNA profiles of Exo were assessed by real-time PCR. Exo-CPC and Exo-MSC from 8 patients were injected intramyocardially in 8 rats each after permanent ligation of the left anterior descending coronary artery. Left ventricular ejection fraction (LVEF) was measured by echocardiography 1 and 4 weeks after MI. Results: Although both Exo-CPC and Exo-MSC inhibited cardiomyocyte (CM) apoptosis after serum starvation in vitro if compared with Exo-F, Exo-CPC showed higher efficacy (21±4% Exo-CPC; 28±4% Exo-MSC; 40±5% Exo-F). IPC of Exo-producing cells further reduced numbers of apoptotic CM (17±1% Exo-CPC; 23±3% Exo-MSC). Exo-CPC, but not Exo-F, were proangiogenic in HUVEC cells. miR-210, miR132 and miR-146a were among the most highly enriched miRNA in Exo-CPC. CM transfected with miR-210 or miR-132 mimics showed increased tolerance to apoptosis, whereas siRNA specific for these miRNA had opposite effects. In vivo, LVEF was significantly improved in hearts injected with Exo-CPC compared to those injected with patient-matched Exo-MSC both at 1 week (87.0±9.9% vs 61.1±11.9; p<0.05) and 4 weeks after MI (75.4±8.9% vs 58.7±18.4%; p<0.05). Conclusion: These results from patient-matched analyses show, for the first time, that Exo-CPC is superior to Exo-MSC at inhibiting CM apoptosis in vitro, and at improving cardiac function after MI in vivo. As a cell-free approach, Exo could streamline clinical translation of regenerative heart therapy

Exosomes secreted by human cardiac progenitor cells inhibit cardiomyocyte apoptosis and improve cardiac function after myocardial infarction

Introduction: Cardiac progenitor cell (CPC) transplantation improves cardiac function after myocardial infarction (MI). This effect is mediated, at least in part, by secreted factors. Exosomes (Exo) are secreted nano-sized membrane vesicles acting as intercellular carriers of proteins and nucleic acids, including microRNA (miRNA). Here, we investigated the role of Exo in the paracrine activity of human CPCs. Methods: Atrial appendage specimens were obtained from patients who underwent heart valve surgery. CPCs were derived from the cellular outgrowth of these specimens using the primary ex vivo tissue culture technique. Exo were purified from CPC-conditioned medium (CM-CPC) using ExoQuick and analysed by transmission electron microscopy (TEM). Functional effects of CM-CPC and purified Exo were assessed in vitro using angiogenesis and apoptosis models in human endothelial cells (HUVECs) and mouse HL-1 cardiomyocytes (CMC), respectively. Apoptosis was assessed by activated caspase 3/7 immunostaining. The effects of cryopreserved Exo derived from human CPCs were compared with those from normal human dermal fibroblasts (NHDF). In vivo studies were performed in a rat model of myocardial infarction (MI) induced by permanent left anterior coronary artery ligation. Exo were injected into the infarct border zone 1 h after coronary ligation. Cardiac function was assessed by echocardiography. Apoptosis was detected by TUNEL. Results: Culture medium conditioned by CPCs (CM-CPC) stimulated tube formation by endothelial cells (HUVECs) and inhibited apoptosis of mouse HL-1 cardiomyocytes after serum deprivation in vitro. Depletion of Exo abolished the proangiogenic and antiapoptotic activities of CM-CPC. Supplementation of Exo-depleted CM with Exo-CPC restored this activity. Exo-CPC inhibited cardiomyocyte apoptosis in a dose-dependent manner, whereas Exo secreted by normal human dermal fibroblasts (Exo-F) did not. miRNA analysis identified miR-146a-3p, miR-181a, miR-132 and miR-210-3p among the most highly upregulated miRNAs in Exo-CPC versus Exo-F (15-, 11-, 5- and 4-fold, respectively). In a rat model of MI, Exo-CPC significantly reduced cardiomyocyte apoptosis and scar, enhanced angiogenesis and preserved LVEF 7 days post-MI (0.8±6.8%) compared with controls (–21.3±4.5%; p<0.05) and Exo-F-injected hearts (–12.0±6.3%). Summary/conclusion: Exo accounts for proangiogenic and antiapoptotic activities of the paracrine secretion of human CPCs, which preserve cardiac function post-MI. As a cell-free product, Exo-CPC may circumvent many of the limitations of cell transplantation for cardiac repair

Pseudoaneurysm following Surgical Resection of Craniopharyngioma: What Is the Best Management?

Craniopharyngiomas are benign tumors of the sellar and parasellar region for which surgical resection remains the treatment of choice. There are many publications on the most frequent postoperative complications, but few reports on subclinical lesions affecting the arteries of the circle of Willis, despite their high morbidity and mortality rate. Trauma-induced aneurysms are infrequent, representing less than 1% of intracranial aneurysms. Iatrogenic intracranial pseudoaneurysms are a subtype of surgically induced aneurysms developed as a result of direct injury to the arterial wall or after dissection of tumors adherent to the vessel adventitia. The natural history of these lesions is not well known because their incidence is extremely low. We report two cases of postoperative aneurysms of the internal carotid artery after craniopharyngioma resection and a brief review on the management of such lesions