Article
Modification of a biodegradable, injectable bone cement with an osteoinductive factor for the management of osteoporotic vertebral fractures
Modifikation eines bioresorbierbaren Knochenzementes mit osteoinduktiven Faktoren zur Therapie osteoporotischer Wirbelkörperfrakturen
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Published: | May 8, 2019 |
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Objective: Osteoporosis is the most common age-related progressive skeletal disease characterized by bone loss and concomitant tendency for osteoporotic vertebral fractures (OVF). OVF are associated with a considerable reduction of quality of life, morbidity and mortality. The management might necessitate fusion surgery, with high rates of implant failure due to osteopenic bone structure. In this study we aim to modify a biodegradable, injectable bone cement for cement-augmentation of pedicle screws to yield an immediate implant fixation, osteoinductive properties to boost the anti-osteoporotic therapy and improve long term implant integrity.
Methods: A bioactive, biodegradable calcium phosphate cement (CaP) was mixed with a synthetic collagen I mimetic peptide (P-15). Different compositions were bound to an anorganic matrix and incubated with human mesenchymal stem cells (MES). Viable cell count was used to monitor cell growth kinetics. Osteoblast-related gene expressions of bone-specific alkaline phosphatase2 (ALPII), osteopontin (BSP-1) and osteocalcin (BGLAP) were analyzed using RT-PCR. Evaluation of the biomechanical abilities of CaP/P-15 composite cement in comparison to standard polymethylmethacrylate (PMMA) cement is currently in preparation.
Results: No alteration in growth kinetics of MES incubated with either growth medium alone, CaP, P-15 or CaP/P-15 were observed. ALPII was increased 22.9±0.011-fold (CaP), 24.01±2.48-fold (P-15) and 32.76±0.212 (CaP/P-15). Osteopontin was increased by 0.51±0.1-fold (CaP), 2.28±0.7-fold (P-15) and 1.3±0.14 (CaP/P-15) while osteocalcin increased by 8.64±0.41-fold (CaP), 13.95±4.30-fold (P-15) and 16.15±0.72 (CaP/P-15). The measurement of the pull out strength of cement-augmented and non-augmented pedicle screws and the measurement of the compression strength of cement-augmented sheep vertebral bodies by a servo-hydraulic system was established.
Conclusion: The calcium phosphate/P-15 composite cement is capable of inducing gene expression profiles associated with osteoblasts in human MES in vitro. The osteoinductive properties of each component show synergistic effects in our study. These results not only warrant future in vivo analysis but also could establish an exciting new tool for the treatment of OVF.