In Vivo Distribution And Safety Of Human Bone Marrow-derived Stromal Cells Following Systemic Infusion

[Objective] To investigate the distribution and safety of human bone marrow-derived stromal cells (hBMSCs) after intravenous injection in nude mice. [Methods] hBMSCs enriched by the gradient centrifugation protocol were ex vivo culture-expanded in Dubecco' modified Eagle's medium-low glucose (DMEM-LG) supplemented with 10% fetal bovine serum (FBS). In the present study, morphological and functional characteristics of hBMSCs were evaluated in terms of phase contrast microscopy, MTT assay, FCM, and osteogenic differentiation assay. Culture-expanded hBMSCs were subsequently infused into the unconditioned recipients via tail vein injection. The donor-derived implantation were identified by reverse transcription polymerase reaction technique (RT-PCR) for human Alu gene and CD45 surface antigen at 7 days and 4 weeks after infusion. Spontaneous transformation following long-term in vitro culture as well as potential tumorigenesis post-transplantation were also evaluated. [Results] the culture-expanded hBMSCs appeared as a uniform population of flbroblastoid-shaped cells that are devoid of CD34 and CD45 positive cells. Osteogenic differentiation potential was identified by depositing a calcium-rich mineralized matrix as evidenced by Alizatin Red S staining. 7 days and 4 weeks after infusion, the presence of infuse cells were detected in multiple organs or tissues recovered from the recipients, including lungs, liver, spleen, kidneys, skeletal muscle, heart, small intestines, and brain. No significant abnormalities were demonstrated among the recipients. [Conclusions] these results indicated that hBMSCs enriched here is morphological and functional characteristic of multipotential mesenchymal progenitor. The multiorgan distribution of the infused hBMSCs here showed no evidence of spontaneous transformation inclination.