Bone-Conditioned Medium Obtained From Calvaria, Mandible, and Tibia Cause an Equivalent TGF-β1 Response In Vitro

Bones with different embryological origin and mode of ossification are supposed to vary in their capacity for supporting graft consolidation. The aim of the current pilot study was to assess the TGF-β1 activity of bone chips obtained from distinct anatomic locations. Conditioned medium was prepared from bone chips harvested from pig calvaria, mandible, and tibia. Human oral fibroblasts were exposed to bone-conditioned medium (BCM) followed by reverse transcriptase polymerase chain reaction of the TGF-β1 target genes. Also an immunoassay for interleukin 11 (IL-11) and TGF-β1 was performed. The impact of BCM on alkaline phosphatase activity was determined with murine MC3T3-E1 osteogenic cells. The authors report here that BCM contains TGF-β1 in the ng/mL range. Bone chips prepared from pig calvaria, mandible, and tibia femur had a similar capacity for increasing the expression of the TGF-β1 target genes IL-11, NOX4, and PRG4. Correspondingly, immunoassays revealed similar production of IL-11 by human oral fibroblasts. Furthermore, conditioned medium obtained from the 3 bones decreased alkaline phosphatase activity in MC3T3-E1 osteogenic cells. These preliminary data demonstrate that particulated bone grafts, regardless of embryological origin, mode of ossification and morphology, release a similar TGF-β1 activity. Address correspondence and reprint requests to Reinhard Gruber, PhD, Department of Oral Biology, School of Dentistry, Medical University of Vienna, Sensengasse 2a, A-1090 Vienna, Austria; E-mail: reinhard.gruber@meduniwien.ac.at Received 10 July, 2017 Accepted 30 September, 2017 BHK and JRGM have contributed equally to this work. This research was partially funded by the Herzfeld Familienstiftung, the Osteology Foundation grant no 14-126 and the School of Dentistry of the Medical University of Vienna. The authors disclosure funding received for this work from National Institutes of Health; Wellcome Trust; Howard Hughes Medical Institute; and other(s). The authors report no conflicts of interest. © 2018 by Mutaz B. Habal, MD.

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