Traumatic Spinal Cord Injury—Repair and Regeneration

BACKGROUND: Traumatic spinal cord injuries (SCI) have devastating consequences for the physical, financial, and psychosocial well-being of patients and their caregivers. Expediently delivering interventions during the early postinjury period can have a tremendous impact on long-term functional recovery. PATHOPHYSIOLOGY: This is largely due to the unique pathophysiology of SCI where the initial traumatic insult (primary injury) is followed by a progressive secondary injury cascade characterized by ischemia, proapoptotic signaling, and peripheral inflammatory cell infiltration. Over the subsequent hours, release of proinflammatory cytokines and cytotoxic debris (DNA, ATP, reactive oxygen species) cyclically adds to the harsh postinjury microenvironment. As the lesions mature into the chronic phase, regeneration is severely impeded by the development of an astroglial-fibrous scar surrounding coalesced cystic cavities. Addressing these challenges forms the basis of current and upcoming treatments for SCI. MANAGEMENT: This paper discusses the evidence-based management of a patient with SCI while emphasizing the importance of early definitive care. Key neuroprotective therapies are summarized including surgical decompression, methylprednisolone, and blood pressure augmentation. We then review exciting neuroprotective interventions on the cusp of translation such as Riluzole, Minocycline, magnesium, therapeutic hypothermia, and CSF drainage. We also explore the most promising neuroregenerative strategies in trial today including Cethrin™, anti-NOGO antibody, cell-based approaches, and bioengineered biomaterials. Each section provides a working knowledge of the key preclinical and patient trials relevant to clinicians while highlighting the pathophysiologic rationale for the therapies. CONCLUSION: We conclude with our perspectives on the future of treatment and research in this rapidly evolving field

Traitement des lésions colorectales radio-induites par injection de Cellules Stromales Mésenchymateuses (CSM) : implication du processus inflammatoire

Throughout the last decades, radiotherapy established as a major tool in the treatment of abdominopelvic cancers. Despite great technological evolutions, radiotherapy remains associated with side effects that can sometimes be really harmful, this being mainly due to the toxicity of ionizing radiations for healthy tissues surrounding the tumor. As part of abdominopelvic radiotherapies, these side effects mainly affect the gastrointestinal tract, which is very sensitive to radiations. The development of curative treatments thus became a priority. Mesenchymal stem cells (MSC) showed their immunomodulatory ability as well as their ability to regenerate tissue in many models. During my thesis, we aimed at giving rise to the therapeutic advantage brought by MSC in the treatment of radioinduced damage as well as the underlying molecular mechanisms. Our results allowed us to demonstrate the efficiency of our treatment with an effect both on the colic epithelial structure and on its contractile functions. We demonstrated that this therapeutical efficiency depends on two processes. Stimulation of the epithelial proliferation through the Wnt pathway allows the epithelial regeneration process to be enhanced. The increased local corticosterone secretion allows the number and the activation state of T lymphocytes to diminish. Our results moreover suggest the existence of a link between the two observed phenomenons thus providing with a new proof of the combinatory effects of MSC therapy.Au cours des dernières décennies, la radiothérapie s'est imposée comme étant un outil majeur dans le traitement des cancers de la zone abdomino-pelvienne. Malgré les évolutions technologiques, la radiothérapie reste associée à des effets secondaires pouvant parfois être très handicapants, principalement dus à la toxicité des rayonnements ionisants pour les tissus sains entourant la tumeur. Dans le cadre des radiothérapies abdomino-pelviennes, ces effets secondaires vont majoritairement toucher le tractus gastro-intestinal, très sensible aux radiations. La mise au point de traitements curatifs est donc devenue une priorité. Les cellules stromales mésenchymateuses (CSM) ont montré leurs capacités de régénération tissulaire et d'immunomodulation dans de nombreux modèles. Durant ma thèse, nous avons voulu mettre en évidence le bénéfice thérapeutique apporté par les CSM dans le traitement des lésions radio-induite, ainsi que les mécanismes sous-jacents. Nos résultats nous ont permis de démontrer l'efficacité de notre traitement, avec un effet à la fois sur la structure et sur les fonctions contractiles coliques. Nous avons pu montrer que cette efficacité thérapeutique dépend de deux processus. La stimulation de la prolifération épithéliale par la voie Wnt permet ainsi d'améliorer la régénération épithéliale. Une sécrétion locale accrue de corticostérone permet quant à elle de diminuer le nombre et l'état d'activation des lymphocytes T. Nos résultats suggèrent également l'existence d'un lien entre les deux phénomènes observés, donnant une nouvelle preuve des effets combinatoires de la thérapie par CS

Traitement des lésions colorectales radio-induites par injection de Cellules Stromales Mésenchymateuses (CSM) (implication du processus inflammatoire)

Au cours des dernières décennies, la radiothérapie s est imposée comme étant un outil majeur dans le traitement des cancers de la zone abdomino-pelvienne. Malgré les évolutions technologiques, la radiothérapie reste associée à des effets secondaires pouvant parfois être très handicapants, principalement dus à la toxicité des rayonnements ionisants pour les tissus sains entourant la tumeur. Dans le cadre des radiothérapies abdomino-pelviennes, ces effets secondaires vont majoritairement toucher le tractus gastro-intestinal, très sensible aux radiations. La mise au point de traitements curatifs est donc devenue une priorité. Les cellules stromales mésenchymateuses (CSM) ont montré leurs capacités de régénération tissulaire et d immunomodulation dans de nombreux modèles. Durant ma thèse, nous avons voulu mettre en évidence le bénéfice thérapeutique apporté par les CSM dans le traitement des lésions radio-induite, ainsi que les mécanismes sous-jacents. Nos résultats nous ont permis de démontrer l efficacité de notre traitement, avec un effet à la fois sur la structure et sur les fonctions contractiles coliques. Nous avons pu montrer que cette efficacité thérapeutique dépend de deux processus. La stimulation de la prolifération épithéliale par la voie Wnt permet ainsi d améliorer la régénération épithéliale. Une sécrétion locale accrue de corticostérone permet quant à elle de diminuer le nombre et l état d activation des lymphocytes T. Nos résultats suggèrent également l existence d un lien entre les deux phénomènes observés, donnant une nouvelle preuve des effets combinatoires de la thérapie par CSMThroughout the last decades, radiotherapy established as a major tool in the treatment of abdominopelvic cancers. Despite great technological evolutions, radiotherapy remains associated with side effects that can sometimes be really harmful, this being mainly due to the toxicity of ionizing radiations for healthy tissues surrounding the tumor. As part of abdominopelvic radiotherapies, these side effects mainly affect the gastrointestinal tract, which is very sensitive to radiations. The development of curative treatments thus became a priority. Mesenchymal stem cells (MSC) showed their immunomodulatory ability as well as their ability to regenerate tissue in many models. During my thesis, we aimed at giving rise to the therapeutic advantage brought by MSC in the treatment of radioinduced damage as well as the underlying molecular mechanisms. Our results allowed us to demonstrate the efficiency of our treatment with an effect both on the colic epithelial structure and on its contractile functions. We demonstrated that this therapeutical efficiency depends on two processes. Stimulation of the epithelial proliferation through the Wnt pathway allows the epithelial regeneration process to be enhanced. The increased local corticosterone secretion allows the number and the activation state of T lymphocytes to diminish. Our results moreover suggest the existence of a link between the two observed phenomenons thus providing with a new proof of the combinatory effects of MSC therapy.PARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Mesenchymal stem cell therapy stimulates endogenous host progenitor cells to improve colonic epithelial regeneration.

Patients who undergo pelvic radiotherapy may develop severe and chronic complications resulting from gastrointestinal alterations. The lack of curative treatment highlights the importance of novel and effective therapeutic strategies. We thus tested the therapeutic benefit of mesenchymal stem cells (MSC) treatment and proposed molecular mechanisms of action. MSC efficacy was tested in an experimental model of radiation-induced severe colonic ulceration histologically similar to that observed in patients. In this model, MSC from bone marrow were administered intravenously, immediately or three weeks (established lesions) after irradiation. MSC therapy reduces radiation-induced colonic ulceration and increases animal survival. MSC treatment induces therapeutic efficacy whatever the time of cell infusion. Infused-MSC engraft in the colon but also increase endogenous MSC mobilization in blood that have lasting benefits over time. In vitro analysis demonstrates that the MSC effect is mediated by paracrine mechanisms through the non-canonical WNT (Wingless integration site) pathway. In irradiated rat colons, MSC treatment increases the expression of the non-canonical WNT4 ligand by epithelial cells. The epithelial regenerative process is improved after MSC injection by stimulation of colonic epithelial cells positive for SOX9 (SRY-box containing gene 9) progenitor/stem cell markers. This study demonstrates that MSC treatment induces stimulation of endogenous host progenitor cells to improve the regenerative process and constitutes an initial approach to arguing in favor of the use of MSC to limit/reduce colorectal damage induced by radiation

Mesenchymal stem cell therapy induces glucocorticoid synthesis in colonic mucosa and suppresses radiation-activated T cells New insights into MSC immunomodulation

International audienceNon-neoplastic tissues around an abdomino-pelvic tumor can be damaged by the radiotherapy protocol, leading to chronic gastrointestinal complications that affect the quality of life with substantial mortality. Stem cell-based approaches using immunosuppressive bone marrow mesenchymal stem cells (MSCs) are promising cell therapy tools. In a rat model of radiation proctitis, weevidenced that a singleMSCinjection reduces colonic mucosa damages induced by ionizing radiation with improvement of the re-epithelization process for up to 21 days. Immune cell infiltrate and inflammatory molecule expressions in the colonic mucosa were investigated. We report that MSC therapy specifically reduces T-cell infiltration and proliferation, and increases apoptosis of radiation-activated T cells. We assessed the underlying molecular mechanisms and found that interleukin-10 and regulatory T lymphocytes are not involved in the immunosuppressive process in this model. However, an increased level of corticosterone secretion and HSD11b1 (11b-hydroxysteroid dehydrogenase type 1)-steroidogenic enzyme expression was detected in colonic mucosa 21 days after MSC treatment. Moreover, blocking the glucocorticoid (GC) receptor using the RU486 molecule statistically enhances the allogenic lymphocyte proliferation inhibited by MSCs in vitro and abrogates the mucosal protection induced by MSC treatment in vivo. Using the irradiation model, we found evidence for a new MSC immunosuppressive mechanism involving GCs. © 2014 Society for Mucosal Immunology

MSC treatment reduces colonic epithelial lesions.

<p>(A) Epithelial injury score. (B) Representative histological pictures of atypical crypts 2 weeks after irradiation and irradiation combined with MSC treatment in the ulcerated zone. Original magnification, x330. (C) MSC therapy increases the number of crypt branching per circular section 2 weeks after irradiation. In A and C results are expressed as mean ±SEM and compared between groups by t-test. (D) Representative pictures of adherent junction staining by immunohistochemistry using anti-β-catenin antibodies (blue staining without counterstaining, original magnification, x250) and (E) mucus staining by alcian blue coloration 2 weeks after irradiation in the healthy margins of the colon. Original magnification, x330 and x900. Functional parameter modifications of the colonic epithelium induced by irradiation were not observed after MSC treatment. All analyses were performed on tissues located inside the irradiated field. In all experiments n = 8 for each group.</p

MSC engraft in colonic mucosa and improve endogenous MSC mobilization into blood.

<p>(A) Intravenous injected MSC engraft in the colon. Detection of GFP-MSC (black arrow) in irradiated (a, b) colonic sub-mucosa or (c) mesentery, 1 week after injection using GFP-specific antibodies. Original magnification, x335 and x1330. (B) Mobilization of endogenous MSC in blood induced by MSC treatment. Representative picture of MSC morphology in blood CFU-F and quantification of CFU-F number per 15×10⁶ plated cells. MSC treatment increases the number of blood-derived CFU-F (n = 11 for each group). Results are expressed as mean ±SEM and compared between groups by one-way ANOVA followed by a Tukey test.</p

<i>In vivo</i> expression of molecular factors involved in the proliferation of epithelial cells 2 weeks after irradiation.

<p>Total proteins and RNA were extracted from irradiated colonic mucosa of different groups and analyzed by (A) ELISA or (B) RT-PCR, respectively. Relative mRNA expression of <i>wnt</i>-related genes were normalized to <i>gapdh</i> housekeeping gene and standardized to control level (control expression = 1). Expression of <i>wnt-1, 2</i> and <i>3</i> was not detected in any of the 3 groups. <i>Wnt4</i> expression increased by 2-fold after irradiation and 4-fold after irradiation and MSC treatment. Results were compared using t-test. (C) Representative pictures of WNT4 immunostaining (blue staining, original magnification, x850) and quantification of the number of WNT4 expressing epithelial cells per crypt 2<b> </b>weeks after irradiation. WNT4 immunostaining in epithelial cells increased after irradiation and increased even more after MSC treatment. Results were compared between groups by one-way ANOVA followed by a Tukey test. *p<0.001 <i>versus</i> control groups. In A, B, and C experiments n = 6 for each groups.</p