Mesenchymal Stem Cells Exhibit Firm Adhesion, Crawling, Spreading and Transmigration across Aortic Endothelial Cells: Effects of Chemokines and Shear

Mesenchymal stem cells (MSCs) have anti-inflammatory and immunosuppressive properties and may be useful in the therapy of diseases such as arteriosclerosis. MSCs have some ability to traffic into inflamed tissues, however to exploit this therapeutically their migratory mechanisms need to be elucidated. This study examines the interaction of murine MSCs (mMSCs) with, and their migration across, murine aortic endothelial cells (MAECs), and the effects of chemokines and shear stress. The interaction of mMSCs with MAECs was examined under physiological flow conditions. mMSCs showed lack of interaction with MAECs under continuous flow. However, when the flow was stopped (for 10min) and then started, mMSCs adhered and crawled on the endothelial surface, extending fine microvillous processes (filopodia). They then spread extending pseudopodia in multiple directions. CXCL9 significantly enhanced the percentage of mMSCs adhering, crawling and spreading and shear forces markedly stimulated crawling and spreading. CXCL9, CXCL16, CCL20 and CCL25 significantly enhanced transendothelial migration across MAECs. The transmigrated mMSCs had down-regulated receptors CXCR3, CXCR6, CCR6 and CCR9. This study furthers the knowledge of MSC transendothelial migration and the effects of chemokines and shear stress which is of relevance to inflammatory diseases such as arteriosclerosis

Intraperitoneal but Not Intravenous Cryopreserved Mesenchymal Stromal Cells Home to the Inflamed Colon and Ameliorate Experimental Colitis

BACKGROUND AND AIMS: Mesenchymal stromal cells (MSCs) were shown to have immunomodulatory activity and have been applied for treating immune-mediated disorders. We compared the homing and therapeutic action of cryopreserved subcutaneous adipose tissue (AT-MSCs) and bone marrow-derived mesenchymal stromal cells (BM-MSCs) in rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis. METHODS: After colonoscopic detection of inflammation AT-MSCs or BM-MSCs were injected intraperitoneally. Colonoscopic and histologic scores were obtained. Density of collagen fibres and apoptotic rates were evaluated. Cytokine levels were measured in supernatants of colon explants. For cell migration studies MSCs and skin fibroblasts were labelled with Tc-99m or CM-DiI and injected intraperitonealy or intravenously. RESULTS: Intraperitoneal injection of AT-MSCs or BM-MSCs reduced the endoscopic and histopathologic severity of colitis, the collagen deposition, and the epithelial apoptosis. Levels of TNF-α and interleukin-1β decreased, while VEGF and TGF-β did not change following cell-therapy. Scintigraphy showed that MSCs migrated towards the inflamed colon and the uptake increased from 0.5 to 24 h. Tc-99m-MSCs injected intravenously distributed into various organs, but not the colon. Cm-DiI-positive MSCs were detected throughout the colon wall 72 h after inoculation, predominantly in the submucosa and muscular layer of inflamed areas. CONCLUSIONS: Intraperitoneally injected cryopreserved MSCs home to and engraft into the inflamed colon and ameliorate TNBS-colitis

Bowel radiation injury: Complexity of the pathophysiology and promises of cell and tissue engineering

Ionizing radiation is effective to treat malignant pelvic cancers, but the toxicity to surrounding healthy tissue remains a substantial limitation. Early and late side effects not only limit the escalation of the radiation dose to the tumor but may also be life-threatening in some patients. Numerous preclinical studies determined specific mechanisms induced after irradiation in different compartments of the intestine. This review outlines the complexity of the pathogenesis, highlighting the roles of the epithelial barrier in the vascular network, and the inflammatory microenvironment, which together lead to chronic fibrosis. Despite the large number of pharmacological molecules available, the studies presented in this review provide encouraging proof of concept regarding the use of mesenchymal stromal cell (MSC) therapy to treat radiation-induced intestinal damage. The therapeutic efficacy of MSCs has been demonstrated in animal models and in patients, but an enormous number of cells and multiple injections are needed due to their poor engraftment capacity. Moreover, it has been observed that although MSCs have pleiotropic effects, some intestinal compartments are less restored after a high dose of irradiation. Future research should seek to optimize the efficacy of the injected cells, particularly with regard to extending their life span in the irradiated tissue. Moreover, improving the host microenvironment, combining MSCs with other specific regenerative cells, or introducing new tissue engineering strategies could be tested as methods to treat the severe side effects of pelvic radiotherapy. © 2016 Cognizant, LLC

Characterisation of a radio-induced colorectal chronic pain model

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Identification and role of serotonin 5‐HT1A and 5‐HT1B receptors in primary cultures of rat embryonic rostral raphe nucleus neurons

International audienceAutoregulatory mechanisms affecting serotonin [5‐hydroxytryptamine (5‐HT)] release and synthesis during the early period of development were investigated in dissociated cell cultures raised from embryonic rostral rat rhombencephalon. The presence of 5‐HT1A and 5‐HT1B receptors in serotoninergic neurons was assessed using binding assays. The involvement of 5‐HT1A and 5‐HT1B receptors in the control of the synthesis and release of [3H]5‐HT was studied using biochemical approaches with several serotoninergic receptor ligands. A mean decrease of 30% in [3H]5‐HT synthesis and release was observed in the presence of 5‐HT (10(‐8) M), the 5‐HT1A agonist 8‐hydroxy‐2‐(di‐n‐propylamino)tetralin (8‐OH‐DPAT), the 5HT1B/1A agonist 5‐methoxy‐3‐(1,2,5,6‐tetrahydro‐4‐pyridinyl)‐1H‐indole (RU 24969), the 5‐HT1B agonist 3‐(1,2,5,6‐tetrahydropyrid‐4‐yl)pyrrolo[3,2‐b]pyrid‐5‐one (CP‐93,129), and the 5‐HT(1D/1B) agonist sumatriptan. Inhibition of 5‐HT synthesis and release induced by 8‐OH‐DPAT was blocked by chiral N‐tert‐butyl‐3‐[1‐[1‐(2‐methoxy)phenyl]piperazinyl]‐1‐phenylpropionam ide dihydrochloride quaternary‐hydrate (WAY 100135) (10(7) M) or methyl 4‐[4‐[4‐(1,1,3‐trioxo‐2H‐1,2‐benzoisothiazol‐2‐yl)butyl]‐1‐p iperazinyl]‐1Hindole‐2‐carboxylate (SDZ 216‐525) (10(‐7)M), and that of CP‐93,129 was blocked by methiothepin (10(‐7) M). Paradoxically, extracellular levels of [3H]5‐HT increased in the presence of 8‐OH‐DPAT and RU 24969 at 10(‐6) M. 5‐HT uptake experiments showed that these two agonists interacted with the 5‐HT transporter. 5‐HT1 binding sites (620 fmol/mg of protein) and 5‐HT1A (482 fmol/mg of protein) and 5‐HT1B (127 fmol/mg of protein) receptors were detected in 12‐day in vitro cell cultures. Experiments carried out with tetrodotoxin suggested that 5‐HT1A receptors are located on nerve cell bodies, whereas 5‐HT1B receptors are located on the nerve terminals. We concluded that autoregulatory mechanisms involving 5‐HT1A and 5‐HT1B autoreceptors are functionally mature in cells from rostral raphe nuclei during the early period of development

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

Persistent visceral allodynia in rats exposed to colorectal irradiation is reversed by mesenchymal stromal cell treatment

International audienceEach year, millions of people worldwide are treated for primary or recurrent pelvic malignancies, involving radiotherapy in almost 50% of cases. Delayed development of visceral complications after radiotherapy is recognized in cancer survivors. Therapeutic doses of radiation may lead to the damage of healthy tissue around the tumor and abdominal pain. Because of the lack of experimental models, the underlying mechanisms of radiation-induced long-lasting visceral pain are still unknown. This makes managing radiation-induced pain difficult, and the therapeutic strategies proposed are mostly inefficient. The aim of our study was to develop an animal model of radiation-induced visceral hypersensitivity to (1) analyze some cellular and molecular mechanisms involved and (2) to test a therapeutic strategy using mesenchymal stromal cells (MSCs). Using a single 27-Grays colorectal irradiation in rats, we showed that such exposure induces a persistent visceral allodynia that is associated with an increased spinal sensitization (enhanced p-ERK neurons), colonic neuroplasticity (as increased density of substance P+ nerve fibers), and colonic mast cell hyperplasia and hypertrophy. Mast cell stabilization by ketotifen provided evidence of their functional involvement in radiation induced allodynia. Finally, intravenous injection of 1.5 million MSCs, 4 weeks after irradiation, induced a time-dependent reversion of the visceral allodynia and a reduction of the number of anatomical interactions between mast cells and PGP9.51 nerve fibers. Moreover, unlike ketotifen, MSC treatment has the key advantage to limit radiation-induced colonic ulceration. This work provides new insights into the potential use of MSCs as cellular therapy in the treatment of pelvic radiation disease