Gene‐activated tissue grafts for sustained bone morphogenetic protein‐2 delivery and bone engineering: Is muscle with fascia superior to muscle and fat?

Abstract

Previously, we have presented an expedited strategy for sustained delivery of bone morphogenetic protein-2 (BMP-2) to bone lesions based on the implantation of gene-activated fat and muscle fragments. The aim of the present in vitro experiments was to evaluate the potential of muscle with fascia as a BMP-2 delivering osteo-regenerative implant in comparison to fat tissue and muscle alone. Subcutaneous fat, muscle, and muscle with fascia were harvested from Fischer 344 rats. The tissues were cut into small pieces and cultured for up to 90 days after direct transduction with adenoviral BMP-2 or green fluorescence protein vectors. Different vector doses were applied, and proliferation, long-term BMP-2 production, and osteogenic differentiation of the 3 different tissues were investigated in vitro. Muscle with fascia produced the largest amounts of BMP-2. Expression of the transgene was detected for up to 90 days. Proliferation was reduced with increased vector doses. Muscle with fascia showed a higher potential for osteogenic differentiation than fat, but it was not improved as compared to muscle alone. A dose of 4 × 10 plaque forming units of the adenoviral BMP-2 vector appeared to be the optimal dose for transduction of muscle with fascia. Because muscle with fascia produced higher amounts of BMP-2 as compared to muscle alone or fat tissue grafts, showing a high potential for osteogenic differentiation, it might represent an improved osteo-regenerative implant facilitating endogenous repair. Future studies should investigate the effect of muscle with fascia transduced with 4 × 10 plaque forming units on bone healing in vivo.

Gene activated adipose tissue fragments as advanced autologous biomaterials for bone regeneration: osteogenic differentiation within the tissue and implications for clinical translation

“…However, calcium accumulation was absent in the SVF when the non-transduced adipose tissue was cultured in normal, non-osteogenic growth medium. Our previous study revealed that calcium deposition was also undetectable in hBMP-2 gene activated adipose tissue cultured in normal growth medium, although similar amounts of hBMP-2 protein were produced as compared to the present study 30 . These data confirmed that the progenitor cells within the SVF require the presence of osteogenic medium for osteoinduction in order to initiate and modulate the differentiation process 31 .…”

Recommendations for improving accuracy of gene expression data in bone and cartilage tissue engineering

“…Is the quality poor, results can deviate considerably in gene expression patterns 63 . In the present study, we utilized a modified Trizol extraction procedure 64 out of economic reasons, whose outcomes in RNA quantities are user-dependent. Since the quality of RNA was good for the present study with RINs being between 6 to 8, the variation in quality cannot as such be based on the method but rather the user who is doing the extraction 65 .…”

BMP-2 Gene Delivery-Based Bone Regeneration in Dentistry

“…In recent years, muscle grafts or adipose tissues have been employed to deliver genetic materials (gene-activated matrices) because the former are abundant sources of MSCs and are easy to harvest [105,106]. In addition, these methods are advantageous because gene delivery to tissues can prevent the complicated ex vivo cell expansion processes necessary for ex vivo gene therapy.…”