Bone-in-a-Box

Bone is an essential stabilizing tissue of the human body, which is highly vascularized. A functional vascular network is crucial for bone regeneration to repair e.g. bone defects in fields such as oral and maxillofacial surgery, orthopedics, and traumatology. The reconstruction of bone defects still remains challenging. Maxillary sinus floor elevation (MSFE) is a frequently performed surgical procedure to restore insufficient jaw bone height in the posterior maxilla, eventually enabling to insert dental implants. Angiogenesis and osteogenesis are tightly coupled processes.

This project aims to develop an in vitro “Bone-in-a-Box” model that accurately recapitulates an in vivo human bone regeneration model, to elucidate blood vessel and bone cell interactions during bone development and repair, and to extrapolate the results to clinical application for bone defect reconstruction such as MSFE.

The “Bone-in-a-Box” consists of a heterogeneous stromal vascular-fraction (SVF), containing adipose stem cells and endothelial cells, a bone slice obtained from alveolar bone next to a removed maxillary third molar, a scaffold material, and culture medium. We hypothesize that the heterogeneous SVF from adipose tissue, bone, growth factors, and hypoxia will all positively contribute to vascularization and concomitant bone regeneration in bone defects.

Once developed, the model allows to test different scaffolds and peptides for their vasculogenic and/or osteogenic properties. Moreover, the model allows in vitro pre-screening of patients with insufficient bone height to allow dental implant placement for prediction of bone regeneration capacity in vivo resulting from the bone augmentation procedure. “Bone-in-a-Box” will represent a humanized in vitro model of bone regeneration, thereby refining, reducing, and ultimately replacing animal models in bone research. For the development and usage of this model, Shenzhen Hoogbio Science & Technology Co., LTD, teams up with Academic Centre for Dentistry Amsterdam (ACTA) and Amsterdam University Medical Centers (Amsterdam UMC).

In conclusion, this project has shown that: 1) SVF in the clinical sinus floor elevation model is also safe in long-term safety studies (10 year follow-up), 2) Micro-spheroid preculturing of SHEDs is beneficial cf. monolayerpreculturing with respect to promoting osteogenic potential, which will likely also be true for SVF, 3) Hypoxia has positive effects on the vaculogenic potential, even under inflammatory conditions, as assessed by upregulation of the angiogenic factor VEGF165, 4) Mechanical loading, one of the components of the “Bone-in-a-Box” model, was shown to increase osteogenic factor expression in native bone matrix, which should be mimicked in the “Bone-in- a-Box” model as well, 5) Functionalization of scaffolds with κ-carrageenan has strong positive osteogenic induction effects on osteoblast precursor cells. Therefore, the project has delivered extensive clues for the development of a “Bone-in-a-Box” device, with defined standard operating procedures for pre-clinical reseach and scaffold/peptide (drug) discovery. Integration of these findings will provide a highly relevant in vitro human bone augmentation model to monitor bone regeneration. It enables unique applications for preclinical screening and evaluation of new scaffolds and peptides as treatment options for patients that need bone augmentation. The knowledge obtained will be used to design novel strategies for musculoskeletal reconstructions in oral and maxillofacial surgery, orthopaedics, and traumatology, as well as patients with tumors, congenital disorders, and degenerative diseases. Therefore, patients worldwide will likely benefit from “Bone-in-a-Box” for reconstruction of bone defects in any part of the skeleton. The innovation is not ready yet to bring to the market/clinic, since the “Bone-in-a-Box” has only been partially developed using different scaffolds and peptides for their osteogenic and vasculogenic stimulatory properties. We have not been able yet with this model to pursue the in vitro pre-screening of patients with insufficient bone height to predict the bone regenerative capacity in vivo after the bone augmentation procedure. However, our results are highly promising indicating the possibility of using “Bone-in-a-Box” to predict the bone regenerative capacity in vivo.