In Vitro andIn Vivo induction of bone formation using a recombinant adenoviral vector carrying the human BMP-2 gene

Abstract

It has been well established that bone morphogenetic protein-2 (BMP-2) can induce bone formation both in vivo and in vitro, although high concentrations (up to milligrams) of BMP-2 have been required to achieve this effect in vivo. Further, clinical applications are usually limited to a single dose at the time of implantation. In an attempt to prolong the transforming effect of BMP-2 we used a recombinant adenoviral vector carrying the human BMP-2 gene (Adv-BMP2) to transduce marrow-derived mesenchymal stem cells (MSC) of skeletally mature male New Zealand white rabbits. The pluripotential MSC were incubated with Adv-BMP2 overnight followed by culture in growth medium for 1 week. Assays on tissue cultures demonstrated that these Adv-BMP2 transduced MSC produced BMP-2 protein, differentiated into an osteoprogenitor line, and induced bone formation in vitro. These MSC had increased alkaline phosphatase activity, increased expression of type I collagen, osteopontin, and osteocalcin mRNA, and induced matrix mineralization compared with both non-transduced cells and cells transduced with a control adenoviral construct. To analyze the osteogenic potential in vivo, Adv-BMP2-transduced MSC were autologously implanted into the intertransverse process space between L5 and L6 of the donor rabbits. The production of new bone was demonstrated by radiographic examination 4 weeks later in areas implanted with cells transduced with Adv-BMP2, whereas no bone was evident at sites implanted with cells transduced with the control adenoviral construct. Histological examination further confirmed the presence of new bone formation. These accumulated data indicate that it is possible to successfully transduce mesenchymal stem cells with a recombinant adenoviral vector carrying the gene for BMP-2 such that these cells will produce BMP-2, differentiate into an osteoprogenitor line, and induce bone formation both in vitro and in vivo. Moreover, incubation of the Adv-BMP2-transduced cells for an additional 7 days in culture before transplantation enhances the success rate in bone formation (three out of three) as compared with our previous report (one out of five, Calcif Tissue Int 63:357-360, 1998).

Efficient bone formation by gene transfer of human LIM mineralization protein-3

“…[16][17][18] Similar to the results in NIH-3T3 and MC3T3-E1 cells, gene transfer of both AdBMP-2 and AdLMP-3 induced bone mineralization in hMSCs, as confirmed by the Von Kossa staining ( Figure 5). …”

Bone regeneration in critical size defects by cell-mediated BMP-2 gene transfer: a comparison of adenoviral vectors and liposomes

“…In most of these studies bone healing could be achieved with a single-dose administration of rhBMP-2. [6][7][8][9][10]14,29,32 Sellers et al 33 reported a mean residence time of rhBMP-2 of 8 days with an elimination half-life of 5.6 days in a cartilage defect model. Explanations for the successful repair of bone defects by a protein that is only present for a few days may be the initiation of differentiation cascades or the recruitment of a sufficient number of the required cells already within the first days.…”

“…7,8 Although encouraging results were achieved with this and other recombinant BMPs, two of which have already successfully traversed clinical trials, several obstacles still have to be overcome. The production of rhBMPs is very expensive, and successful bone healing requires high amounts of protein, 9 which might spread throughout the patient's body with inadvertent accumulation in nontarget organs. Regional gene transfer may therefore provide a viable alternative to protein therapy.…”

Engineered allogeneic mesenchymal stem cells repair femoral segmental defect in rats

“…Past work in our laboratory has shown that we can transfer the gene for bone morphogenetic protein 2, (BMP-2) a growth factor for bone cells, into bone marrow MSC and mesenchymal progenitor cells via recombinant adenovirus. These geneengineered cells continuously expressed BMP-2 protein both in vitro and in vivo, and facilitate cell differentiation into cells of the osteoblast lineage by both autocrine and paracrine [28,40,44].…”