Exploring the effects of the grow factor BMP-9 on articular cartilage-derived progenitor cells to enhance articular cartilage regeneration

Abstract

Articular cartilage lacks intrinsic repairing potential, thus, osteochondral lesions might develop degenerative and lasting defects. These defects lead to pain and disability in young adults, and when these are left untreated, they can develop into early Osteoarthritis (OA). To overcome this problem, cell therapies offer healing and functional replacement of the damaged tissue. In the regenerative medicine field, chondrocytes and Mesenchymal Stem Cells (MSCs) have previously been studied to regenerate the articular cartilage. Recently however, Articular Cartilage Progenitor Cells (ACPCs), a sub-population of chondrocytes, have emerged as an alternative to use in these therapies. Choosing the medium conditions and the correct growth factors, in order to enhance the chondrogenic potential of these cells, has been a major challenge within this field. In contrast with previous studies which used growth factors such as Transforming Growth Factor Beta-1 (TGFβ1) and different Bone Morphogenic Proteins (BMPs), this project focused on exploring the chondrogenic potential effects of BMP9 on ACPCs. Because other factors, such as cell environment and scaffold, are also crucial to improve the cell differentiation and integration in the cartilage native tissue, different three-dimensional (3D) structures were also studied under BMP9 conditions. Norbornene Acid Hyaluronic modified hydrogels (NorHa) were used to improve the chondrogenic differentiation of ACPCs, and polycaprolactone (PCL) 3D printed meshes were assessed as possible articular cartilage implants to guide and reinforce the chondrogenic differentiation.