Evaluation of polyelectrolyte complex-based scaffolds for mesenchymal stem cell therapy in cardiac ischemia treatment

Three-dimensional (3D) scaffolds hold great potential for stem cell-based therapies. Indeed, recent results have shown that biomimetic scaffolds may enhance cell survival and promote an increase in the concentration of therapeutic cells at the injury site. The aim of this work was to engineer an original polymeric scaffold based on the respective beneficial effects of alginate and chitosan. Formulations were made from various alginate/chitosan ratios to form opposite-charge polyelectrolyte complexes (PECs). After freeze-drying, the resultant matrices presented a highly interconnected porous microstructure and mechanical properties suitable for cell culture. In vitro evaluation demonstrated their compatibility with mesenchymal stell cell (MSC) proliferation and their ability to maintain paracrine activity. Finally, the in vivo performance of seeded 3D PEC scaffolds with a polymeric ratio of 40/60 was evaluated after an acute myocardial infarction provoked in a rat model. Evaluation of cardiac function showed a significant increase in the ejection fraction, improved neovascularization, attenuated fibrosis as well as less left ventricular dilatation as compared to an animal control group. These results provide evidence that 3D PEC scaffolds prepared from alginate and chitosan offer an efficient environment for 3D culturing of MSCs and represent an innovative solution for tissue engineering

Evaluation of polyelectrolyte complex-based scaffolds for mesenchymal stem cell therapy in cardiac ischemia treatment

b s t r a c t Three-dimensional (3D) scaffolds hold great potential for stem cell-based therapies. Indeed, recent results have shown that biomimetic scaffolds may enhance cell survival and promote an increase in the concentration of therapeutic cells at the injury site. The aim of this work was to engineer an original polymeric scaffold based on the respective beneficial effects of alginate and chitosan. Formulations were made from various alginate/chitosan ratios to form opposite-charge polyelectrolyte complexes (PECs). After freeze-drying, the resultant matrices presented a highly interconnected porous microstructure and mechanical properties suitable for cell culture. In vitro evaluation demonstrated their compatibility with mesenchymal stell cell (MSC) proliferation and their ability to maintain paracrine activity. Finally, the in vivo performance of seeded 3D PEC scaffolds with a polymeric ratio of 40/60 was evaluated after an acute myocardial infarction provoked in a rat model. Evaluation of cardiac function showed a significant increase in the ejection fraction, improved neovascularization, attenuated fibrosis as well as less left ventricular dilatation as compared to an animal control group. These results provide evidence that 3D PEC scaffolds prepared from alginate and chitosan offer an efficient environment for 3D culturing of MSCs and represent an innovative solution for tissue engineering

Céphalée aux urgences pédiatriques (proposition de protocole de prise en charge diagnostique)

PARIS-BIUM (751062103) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

Clinical safety of computed tomography-guided lumbosacral transforaminal and translaminar epidural and facet joint steroid injections in dogs

peer reviewe

Shopping centres in Slovenia

Članek obravnava nakupovalna središča v Sloveniji ter nekatere njihove značilnosti: velikost, razmestitev, čas nastanka in strukturo trgovin.Shopping centres represent a new phenomenon in Slovene towns. The first ones at the end of the 1980s, but the majority were built between 1997 and 1999. The total surface of shopping areas in shopping centres increased from a modest 10.000 m2 in 1993 to 280.000 m2 in 1999, which amounts to almost a quarter of all shopping areas in Slovenia

Clinical effects of computed tomography-guided lumbosacral facet joint, transforaminal epidural, and translaminar epidural injections of methylprednisolone acetate in healthy dogs.

OBJECTIVE To determine clinical effects of CT-guided lumbosacral facet joint, transforaminal epidural, and translaminar epidural injections of methylprednisolone acetate in healthy dogs. ANIMALS 15 healthy Beagles. PROCEDURES Dogs were randomly assigned to 3 groups (5 dogs/group) and received a single CT-guided lumbosacral facet joint, transforaminal epidural, or translaminar epidural injection of methylprednisolone acetate (0.1 mg/kg). Contrast medium was injected prior to injection of methylprednisolone to verify needle placement. Neurologic examinations were performed 1, 3, 7, and 10 days after the injection. In dogs with neurologic abnormalities, a final neurologic examination was performed 24 days after the procedure. RESULTS Methylprednisolone injections were successfully performed in 14 of the 15 dogs. In 1 dog, vascular puncture occurred, and the methylprednisolone injection was not performed. No major or minor complications were identified during or immediately after the procedure, other than mild transient hyperthermia. During follow-up neurologic examinations, no motor, sensory, or postural deficits were identified, other than mild alterations in the patellar, withdrawal, cranial tibial, and perineal reflexes in some dogs. Overall, altered reflexes were observed in 11 of the 14 dogs, during 27 of 65 neurologic examinations. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that CT-guided lumbosacral facet joint, transforaminal epidural, and translaminar epidural injections of methylprednisolone acetate were associated with few complications in healthy dogs. However, the number of dogs evaluated was small, and additional studies are needed to assess clinical efficacy and safety of these procedures

Computed tomography-guided injection of muscle-derived mesenchimal stem cells in the intervertebral disc of dogs affected by natural disc degeneration: clinical safety and intervertebral disc imaging assessment

Introduction/Purpose: Pre-clinical randomized controlled animal trials have been conducted to evaluate the effects of mesenchymal stem cell (MSCs) transplantation on intervertebral disc (IVD) degeneration. According to their histological results and to imaging assessment of the IVD, intradiscal injection of MSCs is effective, arresting or slowing IVDD process, and is associated with a low complication rate. Few of these studies have been conducted on canine artificially degenerated IVD, using bone marrow or adipose-derived MSCs. Therefore a systematic study on naturally degenerated IVD using MSCs obtained from autologous muscular tissue in dogs is still lacking. The aims of this study were to evaluate the clinical effects of intradiscal injection of muscle-derived MSCs and its effects on imaging features of the intervertebral disc. Methods: Eight experimental dogs were randomly included with the approval of the University’s Animal Care and Use Committee. The final inclusion criteria were the presence of naturally degenerated lumbosacral IVD detected on low-field magnetic resonance (MRI) images and the obtaining of 3 x 106 autologous muscle-derived MSCs. A computed tomography (CT) and MRI examination was performed before and 2 months after the procedure and 13 imaging parameters were assessed. Mesenchymal stem cells diluted in 0,2 ml of FRS Hypothermosol were injected in the lumbosacral IVD under CT-guidance. Clinical examinations were performed regularly during 1 month after the procedure. Results: Six dogs met the inclusion criteria. The remaining 2 dogs did not undergo intradiscal injections, but were used as control group. No major or minor complications were reported during the procedure. No abnormalities were noticed during the clinical examinations. No statistically significant variations of IVD imaging features were noticed before and after the injections. Discussion/Conclusions: Intradiscal injection of muscle-derived MSCs is clinically safe and it is not associated with any progression of the IVD degeneration, detected by CT or low-field MRI imaging. Further studies are needed to assess its efficacy as treatment for the canine natural IVD degeneration

Clinical safety of computed tomography-guided injection of autologous muscle-derived mesenchymal stem cells in the intervertebral disc in dogs

Background: Pre-clinical randomized controlled animal trials have been conducted to evaluate the effect of mesenchymal stem cell (MSCs) transplantation on intervertebral disc (IVD) degeneration. MSCs can be obtained from different tissues, but systematic studies concerning the effects of muscle-derived MSCs injections on canine naturally degenerated IVD are still lacking. The aim of this study is the assessment of the clinical safety of this technique and its effects on the imaging features of the lumbosacral IVD. Methods: Eight adult healthy Beagle dogs were used in this study. In the preliminary phase, viability of muscle-derived MSCs in presence of contrast medium was assessed. In the clinical assessment phase, MSCs were injected in the lumbosacral IVD by computed-tomography (CT) guidance, after the injection of contrast medium to assess the correct intradiscal needle position. Regular clinical examinations were performed and pre- and post-injections (CT) and magnetic resonance imaging (MRI) features of the IVD were assessed. Results: The percentage of viability of MSCs in the presence of contrast medium ranged from 90 to 98%. 3x106 MSCs were obtained from six dogs and injected in the IVD. No major or minor complications were reported during the procedure and no abnormalities were noticed during the clinical examinations. No statistically significant variations were noticed between the pre- and post-injections imaging features. Conclusion: This technique is clinically safe and it is not associated with any progression of the IVD degeneration, detected by CT and MRI imaging

Aedes aegypti larvicidal sesquiterpene alkaloids from Maytenus oblongata

International audienceFour new sesquiterpene alkaloids (1-4) with a beta-dihydroagrofuran skeleton and a new triterpenoid (5) were isolated from an ethyl acetate extract of Maytenus oblongata stems. Their structures were elucidated using 1D and 2D NMR spectroscopy as well as MS and ECD experiments. The M. oblongata stem EtOAc extract and the pure compounds isolated were tested for larvicidal activity against Aedes aegypti under laboratory conditions, and compounds 2 and 3 were found to be active