Clinical Medicine VII. (Poster discussion will take place in the Aula during the Coffee Break)
Introduction: In orthopedics, head and neck surgery, and also in dentistry bone grafts play an important role to reconstruct bone defects and give support for the covering soft tissues. For larger bone deficiencies, the “gold standard” therapy is autogenous bone grafting. However, this procedure can have significant drawbacks: formation of hematoma and higher risk of infection. Thus, there is a great need for solid scaffolds that promote and guide the healing of bone defects. Recently we have developed polyaspartic acid (PASP)-based hydrogels, which can serve as a candidate for bone graft and characterized their biocompatibility in vitro. However, currently no preclinical data are available for PASP-based hydrogels affecting bone regeneration.
Aims: Thus, we aimed to investigate the effects of a PASP-based hydrogel on bone growth in rat calvaria bone defect model.
Methods: In our study we used male Wistar rats. Ethical permission number: PE/EA/917-7/2020. We created two identical bi-cortical defects (6 mm in diameter) in to the calvaria of each animal. PASP-gel based solid disks were placed into one of the defect while the other one was left empty. We sutured the periosteum and the skin per primam after placing the PASP gel. Biological changes in the bone were evaluated using micro-CT analysis and histologic methods. We used t-test for statistical analysis.
Results: After 2 months of healing there were no significant differences between the two groups in bone volume to tissue volume ratio (BV/TV). BV/TV: 16.80±3.06, n=6, and 10.74±2.44, n=6 for the control and PASP groups, respectively (p>0.05). Additionally, CT images revealed no signs of inflammation or further bone resorption around the disks. Moreover, analysis reveal that bone ingrowths started in the empty defects, while in the PASP-filled defects bone grew on the top of the PASP-gels disks.
Conclusion: Based on the CT images PASP hydrogel is a biocompatible material. Additionally, it can guide bone deposition, however, no significant add-on effect was detected on the rate of new bone production compared to the untreated defects.
Funding: The project was supported by the Hungarian Ministry of Human Resources, the New Hungarian Program of National Excellence (ÚNKP-21-4-I).