Mesenchymal Stem Cell Graft Improves Recovery after Spinal Cord Injury in Adult Rats through Neurotrophic and Pro-Angiogenic Actions

Numerous strategies have been managed to improve functional recovery after spinal cord injury (SCI) but an optimal strategy doesn't exist yet. Actually, it is the complexity of the injured spinal cord pathophysiology that begets the multifactorial approaches assessed to favour tissue protection, axonal regrowth and functional recovery. In this context, it appears that mesenchymal stem cells (MSCs) could take an interesting part. The aim of this study is to graft MSCs after a spinal cord compression injury in adult rat to assess their effect on functional recovery and to highlight their mechanisms of action. We found that in intravenously grafted animals, MSCs induce, as early as 1 week after the graft, an improvement of their open field and grid navigation scores compared to control animals. At the histological analysis of their dissected spinal cord, no MSCs were found within the host despite their BrdU labelling performed before the graft, whatever the delay observed: 7, 14 or 21 days. However, a cytokine array performed on spinal cord extracts 3 days after MSC graft reveals a significant increase of NGF expression in the injured tissue. Also, a significant tissue sparing effect of MSC graft was observed. Finally, we also show that MSCs promote vascularisation, as the density of blood vessels within the lesioned area was higher in grafted rats. In conclusion, we bring here some new evidences that MSCs most likely act throughout their secretions and not via their own integration/differentiation within the host tissue

Delivery of biologically active anti-inflammatory cytokines IL-10 and IL-1ra in vivo by the Shigella type III secretion apparatus

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Stem cells in the adult rat spinal cord: plasticity after injury and treadmill training exercise

ABSTRACT Ependymal cells located around the central canal of the adult spinal cord are considered as a source of neural stem cells (NSCs) and represent an interesting pool of endogenous stem cells for repair strategies. Physical exercise is known to increase ependymal cell proliferation, while improving functional recovery. In this work, we further characterized those endogenous NSCs within the normal and injured adult rat spinal cord and investigated the effects of treadmill training using immunohistochemical and behavioural studies. In uninjured untrained rats, Sox-2, a NSC marker, was detected in all ependymal cells of the central canal, and also scattered throughout the parenchyma of the spinal cord. Within the lesion, Sox-2 expression increased transiently, while the number of nestin-positive ependymal cells increased with a concomitant enhancement of proliferation, as indicated by the mitotic markers Ki67 and BrdU. Exercise, which improved functional recovery and autonomous micturition, maintained nestin expression in both injured and uninjured spinal cords, with a positive correlation between locomotor recovery and the number of nestin-positive cells

Neuroprotection.

<p>MSC transplants favor tissue sparing after SCI. Luxol fast blue/hematoxylin staining on cross sections of MSC-grafted (<b>A</b>) and control injured only (<b>B</b>) rats, 21 days after transplantation. The quantification of spared tissue (<b>C</b>), as assessed by the mean ratio of injured area on total area of the sections, reveals a significant decrease of the lesion extension in MSC treated rats compared to control ones. * p<0.05.</p

Applikations- und Kontaktkräfte bei Steigbügelprothesen

Einleitung: Je nach Prothesentyp werden bei der Applikation vergleichsweise hohe Kräfte auf den Mittelohrapparat aufgebracht. Auch die für den Schalltransfer entscheidenden Kontaktkräfte variieren sehr stark. Das Kraftniveau bei der Applikation spiegelt nicht unbedingt die Güte der Verbindung zum langen Ambossfortsatz wider. Wichtige Aspekte bei der Bewertung eines Prothesentyps sind das standardisierte Einsetzen der Prothese, der reproduzierbare Sitz und das sichere Handling auch für weniger erfahrene Operateure.Methoden: Es wurden unterschiedliche Stapesprothesen (z.B. Bucket-, Clip- und Crimp-Prothesen) hinsichtlich der Applikations- und Kontaktkräfte experimentell untersucht. Diese wurden von verschiedenen Operateuren an einem technischen Modell des Amboss appliziert und der räumliche Kraftvektor bei der Applikation wurde erfasst. Die Kontaktkraft zwischen Prothese und Ambossschenkel wurde separat mittels einer Kraftmessdose und eines Laser-Doppler-Vibrometers gemessen. Ergebnisse: Bei der Applikation sind die absoluten Kraftwerte und die Streubreite abhängig vom Prothesentyp und dem Trainingszustand des Operateurs. Gegenüber den Clip-Prothesen, insbesondere solchen aus superelastischem Material, treten bei Crimp-Prothesen hohe Werte auf. Die Clip-Prothesen zeigen eine gute Reproduzierbarkeit mit vergleichsweise geringer Streuung. Konstruktionsbedingt hängt die Applikationskraft bei diesem Prothesentyp direkt mit der Kontaktkraft zusammen. Schlussfolgerung: Insbesondere beim Crimpen ist die Applikationskraft nur schwer kontrollierbar. Dabei kann eine Schädigung des Mittelohrapparats nicht ausgeschlossen werden. Die zur Schallübertragung notwendige Kontaktkraft wird meist ereicht, wobei übermäßig große Kontaktkräfte Nekrosen hervorrufen können.Der Erstautor gibt keinen Interessenkonflikt an

Cytokine array and Elisa results.

<p>(<b>A</b>) Cytokine arrays. Spinal cord extracts from injured vehicle-treated (n = 4) and MSC-treated (n = 5) rats. ß-NGF is significantly increased within the lesioned site 3 days after MSC injection compared to controls. * p<0.05 (mean±S.E.). (<b>B</b>) Histogram showing the amounts, in pg/ml, of the neurotrophins NGF and BDNF as quantified by Elisa, within 2 distinct P12 MSC-conditioned media (M1 and M2). (<b>C</b>) NGF and (<b>D</b>) BDNF fluorescent immunocytochemistry on P12 MSCs <i>in vitro</i>. Scale bar : 50 µm.</p

Blood vessel quantification.

<p>(<b>A</b>–<b>B</b>) RECA-1 immunohistological staining on longitudinal sections of MSC-treated (<b>A</b>) and control vehicle-treated (<b>B</b>) spinal cords. Scale bar: 500 µm. (<b>C</b>) Blood vessel quantification within the lesioned site reveals a significant increase in MSC treated rats compared to control-vehicle treated ones. *p<0.05.</p

MSC viability and CD profile.

<p>Nestin (<b>A</b>) and p75NGFr (<b>B</b>) immunofluorescent stainings on MSCs: The last drop of MSC suspension from the injection needle was placed back into culture to check their viability at the time of injection. (<b>C</b>–<b>F</b>): CD profile of P12 MSC grafted cells, showing their immunoreactivity for CD90 (C) and CD271 (D), and the absence of CD45 (E) and CD11b (F) expression. Scale bar: 50 µm (A, B), 100 µm (C–F).</p

BrdU immunodetection.

<p>(<b>A</b>) BrdU (FITC)-DAPI immunostaining on MSCs cultured with 1.10⁻⁶M BrdU for 72 h, demonstrating that cells were all labeled before being transplanted. (<b>B–C–D</b>) BrdU (Rhodamine) maintenance in MSCs 3 days (<b>B</b>), 7 days <b>(C)</b> and 21 days (<b>D</b>) after the removal of BrdU from the culture medium. (<b>E</b>) BrdU immunodetection (FITC) on a longitudinal spinal cord tissue section from a rat that received 3 ip BrdU injections after spinal cord injury. Scale bar: 50 µm (A), 100 µm (B, C, D) and 200 µm (E).</p