No abstract

Bone marrow stromal cells isolated from a model of osteoon the edges of the trabecular bone of the injected and genesis imperfecta (oim) mice, were transduced with a contralateral femurs by X-gal staining and PCR analysis at retrovirus (BAG) carrying the LacZ and neo r genes after 4, 10, 20, 30 and 40 days after injection. The LacZ gene passage 21. The transduced cells retained the ability to was also detected in the lung and liver of the recipient mice express alkaline phosphatase activity in vitro when treated at 4 and 10 days after injection but not at later time-periods. with recombinant human bone morphogenetic protein twoThe present findings suggest that long-term cultured bone (rhBMP-2), formed cartilage in vitro in aggregate cultures marrow stromal cells from osteogenesis imperfecta (OI) and formed bone in ceramic cubes after 6 weeks of implananimals have the potential to traffic through the circulatory tation in nude mice. X-gal staining of ceramic cubes system, home to bone, form bone and continue to express seeded with the transduced cells demonstrated the presexogenous genes. These findings open the possibility of ence of LacZ-positive cells on the edges of bone and also using these cells as vehicles to deliver normal genes to in the lacunae of the newly formed bone 6 weeks after bone as an alternative approach for the treatment of some implantation. After infusion into femurs of oim mice, the forms of OI and certain other bone acquired and genetic transduced cells were detected in the marrow cavity and diseases.

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Human growth hormone (hGH) is frequently used clinically for growth abnormalities in children and also in adults with growth hormone deficiency. The hormone is usually administered to the individuals by frequent injections. In the present study we investigated the potential of bone marrow stromal cells as vehicles to deliver the GH in vivo by infusion of cells transduced with hGH cDNA into mice femurs. The effect of the hormone on the transduced cells in vitro was also assessed. Bone marrow stromal cells established from a mouse model of human osteogenesis imperfecta mice (oim) were transduced with a retrovirus containing hGH and neomycin resistance genes. The hGH-expressing cells were selected in a medium containing G418 and were then assessed for the hGH expression in vitro. The selected cells synthesized 15 ng/10(6) cells of hGH per 24 h in vitro and exhibited alkaline phosphatase activity when they were treated with the human recombinant bone morphogenetic protein 2 (rhBMP-2). The transduced cells also proliferated faster than the LacZ transduced cells but they did not exhibit a higher rate of matrix synthesis. When 2 x 10(6) hGH+ cells were injected into the femurs of mice, hGH was detected in the serum of the recipient mice up to 10 days after injection. The highest level of growth hormone expression, 750 pg/ml, was detected in the serum of the recipient mice I day after injection of the transduced cells. hGH was also detected in the medium conditioned by cells that were flushed from the femurs of the recipient mice at 1, 3, and 6 days after cell injection. These data indicate that bone marrow stromal cells could potentially be used therapeutically for the delivery of GH or any other therapeutic proteins targeted for bone. The data also suggest that GH may exert its effects on bone marrow stromal cells by increasing their rate of proliferation.