Intravenous human mesenchymal stem cells transplantation in NOD/SCID mice preserve liver integrity of irradiation damage

This work was initiated in an effort to evaluate the potential therapeutic contribution of the infusion of mesenchymal stem cells (MSC) for the correction of liver injuries. We subjected NOD-SCID mice to a 10.5-Gy abdominal irradiation and we tested the biological and histological markers of liver injury in the absence and after infusion of expanded human MSC. Irradiation alone induced a significant elevation of the ALT and AST. Apoptosis in the endothelial layer of vessels was observed. When MSC were infused in mice, a significant decrease of transaminases was measured, and a total disappearance of apoptotic cells. MSC were not found in liver. To explain the protection of liver without MSC engraftment, we hypothesize an indirect action of MSC on the liver via the intestinal tract. Pelvic or total body irradiation induces intestinal absorption defects leading to an alteration of the enterohepatic recirculation of bile acids. This alteration induces an increase in Deoxy Cholic Acid (DCA) which is hepatoxic. In this study, we confirm these results. DCA concentration increased approximately twofold after irradiation but stayed to the baseline level after MSC injection. We propose from our observations that, following irradiation, MSC infusion indirectly corrected liver dysfunction by preventing gut damage. This explanation would be consistent with the absence of MSC engraftment in liver. These results evidenced that MSC treatment of a target organ may have an effect on distant tissues. This observation comes in support to the interest for the use of MSC for cellular therapy in multiple pathologies proposed in the recent years. © 2012 Springer Science+Business Media, LLC

Characterization and histological localization of multipotent mesenchymal stromal cells in the human postnatal thymus

The aim of this work was to characterize multipotent mesenchymal stromal cells (MSCs) in the postnatal human thymus and to localize these MSCs in the organ. Adherent cells isolated from thymus samples were characterized by cell-surface antigen expression. This showed that adherent cells have a MSC profile as assessed by the expression of CD73 and CD105 markers and the lack of CD45 expression. These cells are able to differentiate in vitro into adipocytes, osteoblasts, and chondrocytes and to inhibit mixed lymphocyte reaction. This indicates that isolated cells have all of the characteristics of MSC. The fibroblast colony-forming unit (CFU-F) assay was used to determine their frequency in the postnatal thymus. This frequency was 60.9 ± 14.8 CFU-F per 1 × 105 freshly isolated mononuclear cells. Moreover, taking advantage of CD34 and CD105 expression, immunohistological staining allowed us to localize MSC within interlobular trabeculae in close contact with the outer cortex. Polymerase chain reaction experiments indicated that thymic MSC expressed interleukin-7 and stromal cell-derived factor-1 messenger RNA. Overall, these results confirm previous findings of the presence in the adult human thymus of multipotent MSCs with a phenotype similar to adipose-derived adult stem cells. These results also show for the first time a histological localization of MSC in an organ. This suggests a possible role of thymic MSC in intrathymic differentiation. © Mary Ann Liebert, Inc. 2008

Bone marrow stromal cells spontaneously produce Flt3-ligand: Influence of ionizing radiations and cytokine stimulation

Purpose: To define the ability of human bone marrow (BM) stromal cells to produce fms-like tyrosine kinase 3 (Flt3)-ligand (FL), and the effect of irradiation, tumour necrosis factor-alpha (TNF[image omitted]) or tumour growth factor beta (TGF[image omitted]) on FL production. Material and methods: Primary BM stromal cell cultures were irradiated at 2-10 Gy or were stimulated with TNFα or TGFβ1. The presence of FL was tested in culture supernatants and in cell lysate. The presence of a membrane-bound form of FL and the level of gene expression were also tested. Results: Primary BM stromal cells spontaneously released FL. This production was increased by TNFα but not by TGFβ1 or by irradiation. Chemical induction of osteoblastic differentiation from BM stromal cells also induced an increase in FL release. Conclusions: Our results suggest that the observed increase in FL concentration after in vivo irradiation is an indirect effect. The possible implication of BM stromal cells in these mechanisms is discussed. © 2008 Informa UK Ltd

Human mesenchymal stem cells (MSC) indirectly preserve liver of irradiation damage

The present work was initiated in an effort to evaluate the potential therapeutic contribution of the infusion of MSC for the correction of liver injuries. We subjected NOD-SCID mice to a 10.5 Gy abdominal irradiation and we tested the biological and histological markers of liver injury in the absence and after infusion of expanded human MSC. Irradiation alone induced a significant elevation of transaminases (ALT and AST). Apoptosis in the endothelial layer of vessels was observed. When MSC were infused in mice, a significant decrease of transaminases was measured, and a total disappearance of apoptotic cells. MSC were not found in liver. To explain the protection of liver without MSC engraftment, we hypothesize an indirect action of MSC on the liver via the intestinal tract. Pelvic or total body irradiation induces intestinal absorption defects leading to an alteration of the enterohepatic recirculation of bile acids. This alteration induces an increase in Deoxy Cholic Acid (DCA) which is hepatoxic. In the present study, we confirm these results. DCA concentration increased approximately 2-fold after irradiation but stayed to the baseline level after MSC injection. We propose from our observations that, following irradiation, MSC infusion indirectly corrected liver dysfunction by preventing gut damage. This explanation would be consistent with the absence of MSC engraftment in liver. These results evidenced that MSC treatment of a target organ may have an effect on distant tissues. This observation comes in support to the interest for the use of MSC for cellular therapy in multiple pathologies proposed in the recent years. © Mouiseddine et al

Thérapie cellulaire par cellules souches mésenchymateuses d’une atteinte multi-organes induite par une irradiation gamma : un modèle expérimental

Les cellules souches mésenchymateuses (CSM) sont présentes dans divers tissus de l’organisme adulte dont la moelle osseuse. In vitro, les CSM peuvent se différencier en de nombreux types cellulaires du mésoderme, de l’endoderme et de l’ectoderme ; in vivo, elles ont la capacité de migrer vers un organe lésé. Il existe cependant peu d’informations sur le devenir et le potentiel thérapeutique lors de l’injection de ces cellules souches dans un organisme ayant subit une irradiation accidentelle ou thérapeutique. Nos travaux ont permis de mettre en évidence la répartition spatiale et le taux de prise de greffe des CSM injectées par voie intraveineuse (IV) dans un organisme en fonction de la configuration pour une irradiation gamma. Les CSM ont été isolées à partir de moelle osseuse humaine (CSMh) et injectées à des souris immunodéficientes 24 heures après irradiation. Nous avons mis au point trois types de configurations, une configuration d’irradiation corps entier (ICE) à une dose sublétale de 3,5 Gy et deux configurations d’irradiations localisées, pour lesquelles les souris reçoivent une dose locale totale de 8 Gy au niveau de l’abdomen ou de 30 Gy au niveau de la patte droite postérieure. Le taux d’implantation des CSMh dans les différents organes de l’organisme 15 jours après irradiation a été quantifié par amplification du gène humain de la bêta-Globine par PCR. Puis leur localisation in situ a été mise en évidence par marquage immuno-histochimique de la bêta-2-microglobuline humaine sur des sections d’organes murins possédant de l’ADN humain. En absence d’irradiation, les CSMh ont été détectées en très faible quantité. En revanche, le taux de CSMh implantées est plus important au niveau des zones irradiées à forte dose, suggérant que la colonisation des CSMh dans les tissus après irradiation est dépendante de la configuration d’irradiation. L’implantation des CSMh dans les organes n’appartenant pas aux zones surexposées évoque un état inflammatoire généralisé radio-induit. Cette observation met en avant l’existence d’un effet à distance (abscopal) des atteintes tissulaires locales radio-induites. L’ensemble de nos résultats suggère que la thérapie cellulaire par les CSM pourrait être utilisée pour la régénération des tissus normaux lésés suite à une irradiation accidentelle ou chez les patients soumis à une radiothérapie

Human mesenchymal stem cells favour healing of the cutaneous radiation syndrome in a xenogenic transplant model

It has been suggested that human mesenchymal stem cells (hMSC) could be used to repair numerous injured tissues. We have studied the potential use of hMSC to limit radiation-induced skin lesions. Immunodeficient NOD/ SCID mice were locally irradiated to the leg (30 Gy, dose rate 2.7 Gy/min) using a 60Co source to induce a severe skin lesion. Cultured bone marrow hMSC were delivered intravenously to the mice. The irradiated skin samples were studied for the presence of the human cells, the severity of the lesions and the healing process. Macroscopic analysis and histology results showed that the lesions were evolving to a less severe degree of radiation dermatitis after hMSC transplant when compared to irradiated non-transplanted controls. Clinical scores for the studied skin parameters of treated mice were significantly improved. A faster healing was observed when compared to untreated mouse. Immunohistology and polymerase chain reaction analysis provided evidence that the human cells were found in the irradiated area. These results suggest a possible use of hMSC for the treatment of the early phase of the cutaneous radiation syndrome. A successful transplant of stem cells and subsequent reduction in radiation-induced complication may open the road to completely new strategies in cutaneous radiation syndrome therapy. © Springer-Verlag 2006

Local irradiation not only induces homing of human mesenchymal stem cells at exposed sites but promotes their widespread engraftment to multiple organs: A study of their quantitative distribution after irradiation damage

Mesenchymal stem cells (MSCs) have been shown to migrate to various tissues. There is little information on the fate and potential therapeutic efficacy of the reinfusion of MSCs following total body irradiation (TBI). We addressed this question using human MSC (hMSCs) infused to nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice submitted to TBI. Further, we tested the impact of additional local irradiation (ALI) superimposed to TBI, as a model of accidental irradiation. NOD/SCID mice were transplanted with hMSCs. Group 1 was not irradiated before receiving hMSC infusion. Group 2 received only TBI at a dose of 3.5 Gy, group 3 received local irradiation to the abdomen at a dose of 4.5 Gy in addition to TBI, and group 4 received local irradiation to the leg at 26.5 Gy in addition to TBI. Fifteen days after irradiation, quantitative and spatial distribution of the hMSCs were studied. Histological analysis of mouse tissues confirmed the presence of radio-induced lesions in the irradiated fields. Following their infusion into nonirradiated animals, hMSCs homed at a very low level to various tissues (lung, bone marrow, and muscles) and no significant engraftment was found in other organs. TBI induced an increase of engraftment levels of hMSCs in the brain, heart, bone marrow, and muscles. Abdominal irradiation (AI) as compared with leg irradiation (LI) increased hMSC engraftment in the exposed area (the gut, liver, and spleen). Hind LI as compared with AI increased hMSC engraftment in the exposed area (skin, quadriceps, and muscles). An increase of hMSC engraftment in organs outside the fields of the ALI was also observed. Conversely, following LI, hMSC engraftment was increased in the brain as compared with AI. This study shows that engraftment of hMSCs in NOD/SCID mice with significantly increased in response to tissue injuries following TBI with or without ALI. ALI induced an increase of the level of engraftment at sites outside the local irradiation field, thus suggesting a distant (abscopal) effect of radiation damage. This work supports the use of MSCs to repair damaged normal tissues following accidental irradiation and possibly in patients submitted to radiotherapy. ©AlphaMed Press

Les cellules souches mésenchymateuses favorisent la cicatrisation des lésions cutanées radio induites

De nombreuses études suggèrent que les cellules souches adultes et plus particulièrement les cellules souches Mésenchymateuses humaines (CSMh) pourraient être utilisées pour réparer de nombreux organes. Nous avons étudié la capacité des CSMh à réduire les lésions cutanées radio induite. Pour induire des lésions sévères de la peau, des souris NOD/SCID ont été irradiées au niveau de la patte droite postérieure (30 Gy, débit 2,7 Gy/mn) en utilisant une source gamma au 60Co. Les CSMh ont été injectées 24 heures après irradiation par voie intraveineuse. La présence de cellules humaines, la sévérité des lésions et les processus de cicatrisation ont été étudiés sur les échantillons de peau prélevés de 3 à 8 semaines après irradiation. Nous avons pu observer que chez les souris greffées avec des CSMh, le niveau d’atteinte cutanée radio induite est significativement plus faible. Les scores cliniques utilisés pour l’étude de l’évolution des lésions cutanées de la peau sont significativement améliorés et une cicatrisation plus rapide est observée en comparaison des souris non injectées. La présence de cellules humaines a pu être détectée par PCR quantitative dans les zones cutanées en cours de cicatrisation. Ces résultats suggèrent premièrement que les CSMh sont capables de coloniser la peau altérée par les rayonnements ionisants et deuxièmement qu’elles accélèrent le processus de réparation de ce tissu limitant ainsi les complications tissulaires radio induites. La greffe de CSMh pourrait être un traitement thérapeutique efficace des phases précoces du syndrome cutané radio induit