Explore the vast range of titles available.

Extended esophageal endoscopic submucosal dissection (ESD) is highly responsible for esophageal stricture. We conducted a comparative study in a porcine model to evaluate the effectiveness of adipose tissue-derived stromal cell (ADSC) double cell sheet transplantation. Twelve female pigs were treated with 5 cm long hemi-circumferential ESD and randomized in two groups. ADSC group (n = 6) received 4 double cell sheets of allogenic ADSC on a paper support membrane and control group (n = 6) received 4 paper support membranes. ADSC were labelled with PKH-67 fluorophore to allow probe-based confocal laser endomicroscopie (pCLE) monitoring. After 28 days follow-up, animals were sacrificed. At days 3, 14 and 28, endoscopic evaluation with pCLE and esophagography were performed. One animal from the control group was excluded (anesthetic complication). Animals from ADSC group showed less frequent alimentary trouble (17% vs 80%; P = 0.08) and higher gain weight on day 28. pCLE demonstrated a compatible cell signal in 4 animals of the ADSC group at day 3. In ADSC group, endoscopy showed that 1 out of 6 (17%) animals developed a severe esophageal stricture comparatively to 100% (5/5) in the control group; P = 0.015. Esophagography demonstrated a decreased degree of stricture in the ADSC group on day 14 (44% vs 81%; P = 0.017) and day 28 (46% vs 90%; P = 0.035). Histological analysis showed a decreased fibrosis development in the ADSC group, in terms of surface (9.7 vs 26.1 mm²; P = 0.017) and maximal depth (1.6 vs 3.2 mm; P = 0.052). In this model, transplantation of allogenic ADSC organized in double cell sheets after extended esophegeal ESD is strongly associated with a lower esophageal stricture's rate.

Extracellular vesicles (EV) mediate the therapeutic effects of stem cells but it is unclear whether this involves cardiac regeneration mediated by endogenous cardiomyocyte proliferation. Bi-transgenic MerCreMer/ZEG (n = 15/group) and Mosaic Analysis With Double Markers (MADM; n = 6/group) mouse models underwent permanent coronary artery ligation and received, 3 weeks later, 10 billion EV (from human iPS-derived cardiovascular progenitor cells [CPC]), or saline, injected percutaneously under echo guidance in the peri-infarcted myocardium. Endogenous cardiomyocyte proliferation was tracked by EdU labeling and biphoton microscopy. Other end points, including cardiac function (echocardiography and MRI), histology and transcriptomics were blindly assessed 4-6 weeks after injections. There was no proliferation of cardiomyocytes in either transgenic mouse strains. Nevertheless, EV improved cardiac function in both models. In MerCreMer/ZEG mice, LVEF increased by 18.3 ± 0.2% between baseline and the end-study time point in EV-treated hearts which contrasted with a decrease by 2.3 ± 0.2% in the PBS group; MADM mice featured a similar pattern as intra-myocardial administration of EV improved LVEF by 13.3 ± 0.16% from baseline whereas it decreased by 14.4 ± 0.16% in the control PBS-injected group. This functional improvement was confirmed by MRI and associated with a reduction in infarct size, the decreased expression of several pro-fibrotic genes and an overexpression of the anti-fibrotic miRNA 133-a1 compared to controls. Experiments with an anti-miR133-a demonstrated that the cardio-reparative effects of EV were partly abrogated. EV-CPC do not trigger cardiomyocyte proliferation but still improve cardiac function by other mechanisms which may include the regulation of fibrosis.

Background: Digestive fistulas are disabling and challenging conditions. We explored, in a porcine fistula model and in a murine fistula model, the healing potential of allogenic extracellular vesicles (EVs) derived from porcine adipose tissue stromal cells (ADSCs) and from mechanically stressed murine mesenchymal stem cells (MSC), respectively, both administered at the fistula site through a thermoresponsive pluronic F127 gel. Methods: Esophageal fistulas were surgically created in pigs by placing two plastic stents during 30 days into the neck of pigs. Colon-skin fistulae were surgically created in rats. Animals were randomized into a control group, a group treated with gel and a group treated with gel containing 1.3 x 1011 EVs/ml. Clinical, endoscopic and radiological evaluation of pig fistula healing was performed at day 30 and day 45, before histological assessment. Results: ADSC EVs displayed pro-angiogenic and pro-survival properties in vitro. In pigs in vivo, complete fistula healing was reported to be 100% for the gel + EVs group, 67% for the gel group and 0% for the control. Only the combination of gel and EVs resulted in a statistically significant (i) reduction of fibrosis, (ii) decline of inflammatory response, (iii) decrease in the density of myofibroblasts and (iv) increase of angiogenesis. In rats, similar results were obtained with the diminution of fistula diameter and diminution of output in the gel + EV group compared to the control. Summary/Conclusion: This study provides evidences that ADSC-EVs and MSC-EVs delivered into a thermosensitive gel can induce a therapeutic effect in both preclinical swine and murine fistula model. It opens up new prospects for local minimally invasive EV delivery based on a thermo-actuated administration strategy in fistula therapy and beyond. The combination of gel with EVs may represent the nextgeneration therapeutic options for fistula management deserving to reach further pharmaceutical development steps towards clinical investigation.

Background: Extracellular vesicles (EV) seem to mediate the benefits of cell therapy for ischaemic heart failure but their mechanism of action remains poorly understood. The doubly transgenic fate-mapping MerCreMer/ZEG mice model allows to distinguish whether new cardiomyocytes originate from the division of preexisting ones (GFP+, Troponin [TnT+]) or have differentiated from endogenous progenitors, in which case they stain positive for Lac Z and TnT but negative for GFP. Methods: Myocardial infarction was induced in 12 MerCreMer/ZEG mice by permanent occlusion of the left anterior descending coronary artery. Three weeks later, the surviving mice with a left ventricular ejection fraction (LVEF) <45% received transcutaneous echo-guided injections in the peri-infarct myocardium of EV from 1.4 x 106 human iPS-derived cardiovascular progenitor cells (hiPS-CPg-derived EV) (hiPS-Pg; 10 x 109, n = 6) or PBS (n = 6). Seven days later, four mice (two in each group) were sacrificed for histological assessment. The remaining mice were blindly evaluated by echocardiography 6 weeks after injections, and their hearts were also processed for histology. In parallel, in vitro assays were developed to determine if fluorescently labelled EV were internalized in cultured rat cardiomyocytes. Results: Seven days after EV injection, there was an average of 35 ± 10 cardiomyocytes in the infarcted area of the two treated hearts, which stained positive for TnT and LacZ but negative for GFP, suggesting that they differentiated from endogenous progenitors. Conversely, no TnT+ cardiomyocytes were identified in the scar of PBS-injected hearts. Six weeks after injections, cardiac function was only improved in the EV-treated hearts (n = 4), as evidenced by decreased LV volumes and increased LVEF (+16%) relative to baseline. In vitro, EV were internalized by CM and the transfer of their miRNA and protein payload was demonstrated by a positive intracellular staining for labels specific for these moieties. Summary/Conclusion: hiPS-CPg-derived EV improve the function of chronically infarcted hearts, possibly, in parts, through EV-mediated miR and protein transfer fostering generation of new cardiomyocytes from endogenous sources.

The limited plasticity of adult muscle- or bone marrow– derived stem cells intended for cardiac regeneration impedes their conversion into cardiomyocytes. Since murine skeletal muscle was reported to harbor cardiac precursor cells, we assessed whether similar cells exist in man. Skeletal muscle biopsies obtained from 39 patients were sorted by flow cytometry which generated three populations (CD90+/CD34−, CD34+/CD90−, CD90−/CD34−) expressing similar levels of cardiac (Nkx2.5, cTn-T, cTn-I, Cx43) and skeletal muscle (Myf-5, MyoD, myogenin) mRNAs, as assessed by quantitative reverse transcriptase–PCR. However, compared to unpurified myoblasts, CD34+/CD90− cells expressed greater amounts of endothelium-specific mRNAs and were, therefore, selected for transplantation experiments. Thirty immunosuppressed rats then underwent coronary artery ligation and, 4 weeks later, were intramyocardially injected with culture medium, myoblasts, or CD34+/CD90− cells. After 1 month, left ventricular ejection fraction was significantly higher in the CD34+/CD90− group than in the control and myoblast-injected hearts, which was associated with smaller fibrosis and greater angiogenesis. The low engraftment rate suggested a paracrine mechanism supported by the greater release of growth factors by CD34+/CD90− cells than by unsorted myoblasts. In conclusion, the human skeletal muscle does not harbor cardiac-specified cells but contains a CD34+ fraction endowed with an angiogenic potential providing superior functional and structural benefits.