The Manufacture of GMP-Grade Bone Marrow Stromal Cells with Validated In Vivo Bone-Forming Potential in an Orthopedic Clinical Center in Brazil

A new option for bone regeneration: a rapid methodology for cellularization of allograft with human bone marrow stromal cells with in vivo bone-forming potential

The treatment of severe musculoskeletal injuries, such as loss of bone tissue and consolidation disorders, requires bone transplantation, and the success of this bone reconstruction depends on the grafts transplant's osteogenic, osteoconductive, and osteoinductive properties. Although the gold standard is autograft, it is limited by availability, morbidity, and infection risk. Despite their low capacity for osteoinduction and osteogenesis, decellularized bone allografts have been used in the search for alternative therapeutic strategies to improve bone regeneration. Considering that bone marrow stromal cells (BMSCs) are responsible for the maintenance of bone turnover throughout life, we believe that associating BMSCs with allograft could produce a material that is biologically similar to autologous bone graft. For this reason, this study evaluated the osteogenic potential of bone allograft cellularized with BMSCs. First, BMSC was characterized and allograft decellularization was confirmed by histology, scanning electron microscopy, and DNA quantification. Subsequently, the BMSCs and allografts were associated and evaluated for adhesion, proliferation, and in vitro and in vivo osteogenic potential. We demonstrated that, after 2 hours, BMSCs had already adhered to the surface of allografts and remained viable for 14 days. In vitro osteogenic assays indicated increased osteogenic potential of allografts compared with beta-tricalcium phosphate (β-TCP). In vivo transplantation assays in immunodeficient mice confirmed the allograft's potential to induce bone formation, with significantly better results than β-TCP. Finally, our results indicate that allograft can provide structural support for BMSC adhesion, offering a favorable microenvironment for cell survival and differentiation and inducing new bone formation. Taken together, our data indicate that this rapid methodology for cellularization of allograft with BMSCs might be a new therapeutic alternative in regenerative medicine and bone bioengineering.

Reduced Osteogenic Differentiation Potential In Vivo in Acute Myeloid Leukaemia Patients Correlates with Decreased BMP4 Expression in Mesenchymal Stromal Cells

The osteogenic differentiation potential of mesenchymal stromal cells (hMSCs) is an essential process for the haematopoiesis and the maintenance of haematopoietic stem cells (HSCs). Therefore, the aim of this work was to evaluate this potential in hMSCs from AML patients (hMSCs-AML) and whether it is associated with BMP4 expression. The results showed that bone formation potential in vivo was reduced in hMSCs-AML compared to hMSCs from healthy donors (hMSCs-HD). Moreover, the fact that hMSCs-AML were not able to develop supportive haematopoietic cells or to differentiate into osteocytes suggests possible changes in the bone marrow microenvironment. Furthermore, the expression of BMP4 was decreased, indicating a lack of gene expression committed to the osteogenic lineage. Overall, these alterations could be associated with changes in the maintenance of HSCs, the leukaemic transformation process and the development of AML.

The Isolation and Manufacture of GMP-Grade Bone Marrow Stromal Cells from Bone Specimens

Bone marrow stromal cells (BMSCs, also known as bone marrow mesenchymal stem cells) are a plastic-adherent heterogeneous cell population that contain inherent skeletal progenitors and a subset of multipotential skeletal stem cells (SSCs). Application of BMSCs in therapeutic protocols implies its isolation and expansion under good manufacturing practices (GMP). Here we describe the procedures we have found to successfully generate practical BMSCs numbers, with preserved biological potency.

Predifferentiated Gingival Stem Cell-Induced Bone Regeneration in Rat Alveolar Bone Defect Model

Cleft alveolus, a common birth defect of the maxillary bone, affects one in 700 live births every year. This defect is traditionally restored by autogenous bone grafts or allografts, which may possibly cause complications. Cell-based therapies using the mesenchymal stem cells (MSCs) derived from human gingiva (gingiva-derived mesenchymal stem cells [GMSCs]) is attracting the research interest due to their highly proliferative and multilineage differentiation capacity. Undifferentiated GMSCs expressed high level of MSC-distinctive surface antigens, including CD73, CD105, CD90, and CD166. Importantly, GMSCs induced with osteogenic medium for a week increased the surface markers of osteogenic phenotypes, such as CD10, CD92, and CD140b, indicating their osteogenic potential. The objective of this study was to assess the bone regenerative efficacy of predifferentiated GMSCs (dGMSCs) toward an osteogenic lineage in combination with a self-assembling hydrogel scaffold PuraMatrix™ (PM) and/or bone morphogenetic protein 2 (BMP2), on a rodent model of maxillary alveolar bone defect. A critical size maxillary alveolar defect of 7 mm × 1 mm × 1 mm was surgically created in athymic nude rats. The defect was filled with either PM/BMP2 or PM/dGMSCs or the combination of three (PM/dGMSCs/BMP2) and the bone regeneration was evaluated at 4 and 8 weeks postsurgery. New bone formation was evaluated by microcomputed tomography and histology using Hematoxylin and Eosin staining. The results demonstrated the absence of spontaneous bone healing, either at 4 or 8 weeks postsurgery in the defect group. However, the PM/dGMSCs/BMP2 group showed significant enhancement in bone regeneration at 4 and 8 weeks postsurgery, compared with the transplantation of individual material/cells alone. Apart from developing the smallest critical size defect, results showed that PM/dGMSCs/BMP2 could serve as a promising option for the regeneration of bone in the cranio/maxillofacial region in humans.