TGF-β Activity of a Demineralized Bone Matrix

Allografts consisting of demineralized bone matrix (DBM) are supposed to retain the growth factors of native bone. However, it is not clear if transforming growth factor beta 1 (TGF-beta 1) is maintained in the acid-extracted human bone. To this aim, the aqueous solutions of supernatants and acid lysates of OraGRAFT(R) Demineralized Cortical Particulate and OraGRAFT(R) Prime were prepared. Exposing fibroblasts to the aqueous solution caused a TGF-beta receptor type I kinase-inhibitor SB431542-dependent increase in interleukin 11 (IL11), NADPH oxidase 4 (NOX4), and proteoglycan 4 (PRG4) expression. Interleukin 11 expression and the presence of TGF-beta 1 in the aqueous solutions were confirmed by immunoassay. Immunofluorescence further confirmed the nuclear translocation of Smad2/3 when fibroblasts were exposed to the aqueous solutions of both allografts. Moreover, allografts released matrix metalloprotease-2 activity and blocking proteases diminished the cellular TGF-beta response to the supernatant. These results suggest that TGF-beta is preserved upon the processing of OraGRAFT(R) and released by proteolytic activity into the aqueous solution.

Automated summary

The research found that TGF-beta is preserved and released in allografts through exposure to aqueous solutions, triggering cellular responses.