dissolution-dynamic-nuclear-polarization-instrumentation-for-real

Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR

The main limitation of NMR-based investigations is low sensitivity. This prompts for long acquisition times, thus preventing real-time NMR measurements of ...

adsc-sheet-transplantation-to-prevent-stricture-after-extended

ADSC-sheet Transplantation to Prevent Stricture after Extended Esophageal Endoscopic Submucosal Dissection

In past years, the cell-sheet construct has spurred wide interest in regenerative medicine, especially for reconstructive surgery procedures. The ...

Université Paris Descartes

Université Paris Descartes Sorbonne Paris Cité

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.

Does the human skeletal muscle harbor the murine equivalents of cardiac precursor cells?

Intramyocardial injections of cells can damage tissue and enhance dissociation-induced cell death. We assessed whether epicardial delivery of cell sheets could overcome these issues in a rat model of chronic myocardial infarction.

Epicardial adipose stem cell sheets results in greater post-infarction survival than intramyocardial injections.

Purpose:To demonstrate that strandlike hypointense signals seen in the myocardium of normal rat hearts correspond to myocardial microvessels with high-spatial-resolution susceptibility-weighted (SW) magnetic resonance (MR) imaging without injection of contrast medium.Materials and Methods:Animal experiments were performed with institutional animal care committee approval. Ex vivo cardiac MR imaging was performed in 10 normal Wistar rats with a 4.7-T imager and a cryogenic probe. The hypothesis that thin tubular hypointense signals in the myocardium of rat hearts at SW MR imaging sequences (group 1, n = 6; in-plane resolution, 39 Î¼m) represent intramyocardial microvessels was tested. A superparamagnetic intravascular contrast agent (ferumoxsil; Lumirem) was used to explore the distribution of the intramyocardial microvessels (group 2, n = 4; three-dimensional fast imaging with steady-state free precession sequences). Nonparametric Mann-Whitney tests were performed to compare groups 1 and 2 both for microvascular densities (MVD) on histologic sections and for MR imaging signal intensities (SIs). Wilcoxon signed rank tests were used for paired comparison of subepicardial and subendocardial MVD and SI within groups.Results:Ferumoxsil opacified the coronary microvasculature (group 2) on MR-matched histologic sections. No statistically significant difference was found between groups 1 and 2 for either MVD or MR imaging SI expressed as ratios between subendocardium and subepicardium (P = .40 and P = .46, respectively). The comparison of mean subendocardial and subepicardial SI within groups revealed significantly more microvessels in the subepicardium with MR (group 1: P = .01; group 2: P = .004).Conclusion:Myocardial microvessels appear as strandlike structures on high-spatial-resolution SW MR images without the aid of contrast medium injection.Â© RSNA, 2013Supplemental material:http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13122152/-/DC1.

Evaluation of Rat Heart Microvasculature with High-Spatial-Resolution Susceptibility-weighted MR Imaging.

To determine whether functional imaging using MRI and fibered confocal fluorescence microscopy (FCFM) could be used to monitor cell therapy by mural progenitor cells (MPC).

Multiparametric optical and MR imaging demonstrate inhibition of tumor angiogenesis natural history by mural cell therapy.

Our objective was to determine if supersonic shear wave elastography (SSWE) can detect changes in stiffness of a breast cancer model under therapy. A human invasive carcinoma was implanted in 22 mice. Eleven were treated with an anti-angiogenic therapy and 11 with glucose for 24 d. Tumor volume and stiffness were assessed during 2 wk before treatment and 0, 7, 12, 20 and 24 d after the start of therapy using SSWE. Pathology was assessed after 12 and 24 d of treatment. We found that response to therapy was associated with early softening of treated tumors only, resulting in a significant difference from non-treated tumors after 12 d of treatment (p = 0.03). On pathology, large areas of necrosis were observed at 12 d in treated tumors. Although treatment was still effective, treated tumors subsequently stiffened during a second phase of the treatment (days 12-24), with a small amount of necrosis observed on pathology on day 24. In conclusion, SSWE was able to measure changes in the stiffness of tumors in response to anti-cancer treatment. However, stiffness changes associated with good response to treatment may change over time, and increased stiffness may also reflect therapy efficacy.

Supersonic Shear Wave Elastography of Response to Anti-cancer Therapy in a Xenograft Tumor Model.

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.

Cell Sheet Transplantation for Esophageal Stricture Prevention after Endoscopic Submucosal Dissection in a Porcine Model.

Background Fistulas after esophagectomy are a significant cause of morbidity and mortality. Several endoscopic treatments have been attempted, with varying success. An experimental model that could validate new approaches such as cellular therapies is highly desirable. The aim of this study was to create a chronic esophageal enterocutaneous fistula model in order to study future experimental treatment options. Methods Eight pigs (six 35-kg young German and two 50-kg adult Yucatan pigs) were used. Through a left and right cervicotomy, under endoscopic view, 1 (group A, n = 6) or 2 (group B, n = 7) plastic catheters were introduced into the esophagus 30 cm from the dental arches bilaterally and left in place for 1 month. Radiologic and endoscopic fistula tract evaluations were performed at postoperative day (POD; 30) and at sacrifice (POD 45). Results Three fistulas were excluded from the study because of early (POD 5) dislodgment of the catheter, with complete fistula closure. At catheter removal (POD 30), the external orifice was larger in group B (5.2 ± 1.1 mm vs 2.6 ± 0.4 mm) with more severe inflammation (72% vs 33%). At POD 45, the external orifice was closed in all fistulas in group A and in 1/7 in group B. At necropsy, the fistula tract was still present in all animals. Yucatan pigs showed more complex tracts, with a high level of necrosis and substantial fibrotic infiltration. Conclusions In this article, we show a reproducible, safe, and effective technique to create an esophagocutaneous fistula model in a large experimental animal.

A Newly Designed Enterocutaneous Esophageal Fistula Model in the Pig.

Cell sheet technology opens new perspectives in tissue regeneration therapy by providing readily implantable, scaffold-free 3D tissue constructs. Many studies have focused on the therapeutic effects of cell sheet implantation while relatively little attention has concerned the fate of the implanted cells in vivo. The aim of the present study was to track longitudinally the cells implanted in the cell sheets in vivo in target tissues. To this end we (i) endowed bone marrow-derived mesenchymal stem cells (BMMSCs) with imaging properties by double labeling with fluorescent and magnetic tracers, (ii) applied BMMSC cell sheets to a digestive fistula model in mice, (iii) tracked the BMMSC fate in vivo by MRI and probe-based confocal laser endomicroscopy (pCLE), and (iv) quantified healing of the fistula. We show that image-guided longitudinal follow-up can document both the fate of the cell sheet-derived BMMSCs and their healing capacity. Moreover, our theranostic approach informs on the mechanism of action, either directly by integration of cell sheet-derived BMMSCs into the host tissue or indirectly through the release of signaling molecules in the host tissue. Multimodal imaging and clinical evaluation converged to attest that cell sheet grafting resulted in minimal clinical inflammation, improved fistula healing, reduced tissue fibrosis and enhanced microvasculature density. At the molecular level, cell sheet transplantation induced an increase in the expression of anti-inflammatory cytokines (TGF-ß2 and IL-10) and host intestinal growth factors involved in tissue repair (EGF and VEGF). Multimodal imaging is useful for tracking cell sheets and for noninvasive follow-up of their regenerative properties.

Designing 3D Mesenchymal Stem Cell Sheets Merging Magnetic and Fluorescent Features: When Cell Sheet Technology Meets Image-Guided Cell Therapy.

Pyruvate membrane crossing and its lactate dehydrogenase-mediated conversion to lactate in cells featuring different levels of expression of membrane monocarboxylate transporters (MCT4) were probed by dissolution dynamic nuclear polarization-enhanced NMR. Hyperpolarized (13) C-1-labeled pyruvate was transferred to suspensions of rodent tumor cell carcinoma, cell line 39. The pyruvate-to-lactate conversion rate monitored by dissolution dynamic nuclear polarization-NMR in carcinoma cells featuring native MCT4 expression level was lower than the rate observed for cells in which the human MCT4 gene was overexpressed. The enzymatic activity of lactate dehydrogenase was also assessed in buffer solutions, following the real-time pyruvate-to-lactate conversion speeds at different enzyme concentrations. Copyright © 2016 John Wiley & Sons, Ltd.

Pyruvate cellular uptake and enzymatic conversion probed by dissolution DNP-NMR: the impact of overexpressed membrane transporters.

The combination of mesenchymal stem cells and tissue-engineered fibrin patches improves the therapeutic efficacy of stem cells. In vivo cardiac magnetic resonance (4.7 Tesla) and ex vivo high-spatial resolution CMR were used to track the fate of human bone marrow-derived mesenchymal stem cell (BMSC) delivered on an epicardial scaffold and more specifically assess their potential intramyocardial migration. Fifty-seven nude rats underwent permanent coronary artery ligation. Two months later, those with a left ventricular ejection fraction ≤55% were randomly allocated to receive a patch loaded with human BMSC (BMSC-P, n = 10), a patch loaded with BMSCs labelled with iron oxide nanoparticles (BMSC*-P, n = 12), an acellular patch (A-P, n = 8) or to serve as sham-operated animals (SHAM, n = 7). BMSC secretion of cytokines and growth factors was evaluated with flow-cytometry. Cardiac functional parameters of cell-treated groups (BMSC*-P and BMSC-P) yielded significantly better outcomes than the SHAM group (p = 0.044 and p = 0.026, respectively, for ejection fraction). Angiogenesis was higher in the cell-patch than in control groups (e.g. BMSC*P vs. SHAM: p = 0.007). No BMSCs were identified into the myocardium on cardiac magnetic resonance or histological sections, although persisting BMSCs were identified on the epicardial surface 21 days post-transplantation in 10% of rats hearts (Lamin A/C and CD90 positive). Cytokine and growth factor profiling demonstrated an increase in their release by cells seeded in patches. The absence of stem cell migration into the myocardium and the persistence of stem cells on the epicardial surface suggest that fibrin patches are likely to act predominantly as reservoirs of paracrine factors. Copyright © 2017 John Wiley & Sons, Ltd.

ArticleTotal : 2	Year
Publication title Cited by 14	2016
Publication title Cited by 13	2017

Article	Year
Does the human skeletal muscle harbor the murine equivalents of cardiac precursor cells? Molecular therapy : the journal of the American Society of Gene Therapy\| PubMed ID: 19223868	2009
Epicardial adipose stem cell sheets results in greater post-infarction survival than intramyocardial injections. Cardiovascular research\| PubMed ID: 21565832	2011
Evaluation of Rat Heart Microvasculature with High-Spatial-Resolution Susceptibility-weighted MR Imaging. Radiology\| PubMed ID: 23687173	2013
Multiparametric optical and MR imaging demonstrate inhibition of tumor angiogenesis natural history by mural cell therapy. Magnetic resonance in medicine\| PubMed ID: 24123113	2014
Supersonic Shear Wave Elastography of Response to Anti-cancer Therapy in a Xenograft Tumor Model. Ultrasound in medicine & biology\| PubMed ID: 26746382	2015
Cell Sheet Transplantation for Esophageal Stricture Prevention after Endoscopic Submucosal Dissection in a Porcine Model. PloS one\| PubMed ID: 26930409	2016
A Newly Designed Enterocutaneous Esophageal Fistula Model in the Pig. Surgical innovation\| PubMed ID: 26989046	2016
Designing 3D Mesenchymal Stem Cell Sheets Merging Magnetic and Fluorescent Features: When Cell Sheet Technology Meets Image-Guided Cell Therapy. Theranostics\| PubMed ID: 27022420	2016
Pyruvate cellular uptake and enzymatic conversion probed by dissolution DNP-NMR: the impact of overexpressed membrane transporters. Magnetic resonance in chemistry : MRC\| PubMed ID: 27859555	2016
Bone marrow-derived mesenchymal stem cell-loaded fibrin patches act as a reservoir of paracrine factors in chronic myocardial infarction. Journal of tissue engineering and regenerative medicine\| PubMed ID: 28156084	2017

Laetitia Pidial

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