Heterotopic Ossification of Degenerating Rat Skeletal Muscle Induced by Adenovirus-Mediated Transfer of Bone Morphogenetic Protein-2 Gene

Abstract

In vivo gene transfer is a recently developed device for efficient delivery of a therapeutic recombinant protein.We formulated the hypothesis that a high level of expression of bone morphogenetic protein 2 (BMP-2) could be a future therapeutic modality in terms of inducing substantial bone formation in vivo. First, to test this hypothesis, adenoviruses carrying BMP-2 gene were directly injected into the soleus muscle of adult rat. The BMP-2 gene was successfully overexpressed in the target muscle by adenovirus-mediated transfer, whereas bone formation in and around the muscle failed to occur in this case. Second, to recruit putative osteoprogenitor cells, we then induced ischemic degeneration of the target muscle by orthotopically grafting it simultaneously with the gene transfer. The combination of BMP-2 gene transfer and orthotopic muscle grafting resulted in successful ossification of almost the whole grafted muscle, whereas neither muscle grafting alone nor the combination of muscle grafting and adenovirus-mediated transfer of reporter gene LacZ induced any bone formation in the muscle. The ossification process was evident by positive von Kossa staining of the histological sections and roentgenographical radio-opacity of the region. It was also found that the BMP-2 transgene overexpressed in grafted muscles inhibited muscle regeneration, which should otherwise follow the muscle degeneration. We further demonstrated an up-regulation of BMP receptor type IA in grafted muscles, suggesting its involvement in the bone-formation process.

Association of vitamin D deficiency, secondary hyperparathyroidism, and heterotopic ossification in spinal cord injury

“…With rare exception, heterotopic bone is found below the neurological level of injury [26]. In traumatic SCI, as well as other traumatic conditions, the two primary factors that appear responsible for the etiology of bone deposition at a cellular and molecular level appear to be the presence of BMPs [29][30][31][32] and the ischemic degeneration of involved muscle [33][34]. The sources of BMPs in muscle are mesenchymal cells and endothelial cells; the target cells in the muscle that BMPs act upon are mesenchymal stem cells and smooth muscle cells [35].…”

Ex vivo gene therapy with stromal cells transduced with a retroviral vector containing the BMP4 gene completely heals critical size calvarial defect in rats

“…Although there are several studies which have shown evidence for skeletal regeneration in vivo using ex vivo modified stromal cells, myoblasts, or fibroblasts, 10,15,16,22,24,25 our study is unique in that it provides quantitative data on the extent of healing by valid bone density measurements. Furthermore, our data demonstrate that the healing of a critical calvarial defect is dependent on the time of exposure, as well as the number of BMP4-expressing stromal cells implanted.…”

“…[9][10][11][12][13][14] Accordingly, it has been shown that adenoviral transfer of BMP2 can stimulate bone formation at ectopic sites 16 and promote healing of a segmental defect in long bones. 9,14 In as much as the results of previous work using adenoviral vectors are promising and adenoviral vector systems have the advantage of high levels of gene expression acutely, adenoviral vector systems also have two important disadvantages: (1) these vectors, even with the use of 'gutted' adenoviral vectors, frequently elicit strong immune response, which is highly undesirable.…”

Bone formation following transplantation of genetically modified primary bone marrow stromal cells

“…Indeed, direct injection of adenoviral vector encoding BMP-2 induces little bone formation in immunocompetent animals and may cause substantial inflammation at the injection site [9,21].…”