Autogenous Mesenchymal Stem Cell Culture-Derived Signalling Molecules as Enhancers of Bone Formation in Bone Grafting

1. Aims and Hypothesis

Based in previously reported studies and following a translational approach, a hypothesis that the paracrine effect linked to cultured autogenous growth factors and cytokines at physiologic concentrations acting locally in grafted sites might promote a faster and/or more efficient cell response and consequently induce a more significant/faster bone formation was considered. The presence of these molecules added to synthetic bone substitutes might act positively in terms of local cell recruitment (chemotaxis), proliferation, differentiation and bone protein synthesis. Also, recurrent biological hazards involved in conventional tissue-engineered cellular graft compounds, usually linked to the ex vivo manipulation of cells in terms of tumorigenicity, immunogenicity and the previously reported cell dedifferentiation phenomenon would be mitigated by the exclusion of the cell element of this process, as they are considered by some reports to present unpredictable mitotic behavior once artificially cultured. The present study aims to further extend this translational investigation following preclinical studies by the principal investigator, proposing a prospective randomized controlled clinical trial on the possible benefits associated with the application of a tissue-engineered bone graft compound containing concentrated autogenous cell-cultured medium (CM) and an hydroxylapatite/beta-tricalcium phosphate-based synthetic bone substitute (HP/β-TCP ceramic). Specific aims include analyses on the density of the newly formed calcified tissue by computed tomography (CBCTs), expression of specific immunohistochemical bone formation markers (RT-PCR) and histomorphometric bone quantity evaluation. In a split-mouth study model, the resultant bone formation after HP/β-TCP grafting with and without CM will be analyzed, compared and quantified at different time points. 2. Materials and Methods

2.1- Study design

A prospective split-mouth randomized controlled clinical trial was chosen as study design for the present investigation. After protocol approval by the Research Ethics Committee and registration at the clinical trials.gov platform, following CONSORT guidelines, 20 consecutive patients who seek maxillary oral rehabilitation at the Department of Prosthetic Dentistry of the School of Health and Life Sciences - PUCRS, Brazil, will be invited to participate in the present investigation.

2.2 - Lipoplasty and human adipose stem cells (hASCs) harvesting/culture.