[Use of human progenitor cells in the treatment of cartilage damage]

Precise Lubrication and Protection of Cartilage Damage by Targeting Hydrogel Microsphere

Osteoarthritis (OA) is a degenerative bone and joint disease characterized by decreased cartilage lubrication, leading to continuous wear and ultimately irreversible damage. This situation is particularly challenging for early-stage OA, as current bio-lubricants lack precise targeting for small inflammatory lesions. In this work, an antibody-mediated targeting hydrogel microspheres (HMS) is developed to precisely lubricate the local injury site of cartilage and prevent the progression of early OA. Anti-Collagen type I (Anti-Col1) is an antibody that targets cartilage injury sites in early OA stages. It is anchored on a HMS matrix made of Gelatin methacrylate (GelMA) and poly (sulfobetaine methacrylate) (PSBMA) to create targeted HMS (T-G/S HMS). The T-G/S HMS's high hydrophilicity, along with the dynamic interaction between its surficial Anti-Col1 and the Col1 on cartilage injury site, ensures its precise and effective lubrication of early OA lesions. Consequently, injecting T-G/S HMS into rats with early OA significantly slows disease progression and reduces symptoms. In conclusion, the developed injectable targeted lubricating HMS and the precisely targeted lubrication strategy represent a promising, convenient technique for treating OA, particularly for slowing the early-stage OA progression.

Post-decellularization techniques ameliorate cartilage decellularization process for tissue engineering applications

Due to the current lack of innovative and effective therapeutic approaches, tissue engineering (TE) has attracted much attention during the last decades providing new hopes for the treatment of several degenerative disorders. Tissue engineering is a complex procedure, which includes processes of decellularization and recellularization of biological tissues or functionalization of artificial scaffolds by active cells. In this review, we have first discussed those conventional steps, which have led to great advancements during the last several years. Moreover, we have paid special attention to the new methods of post-decellularization that can significantly ameliorate the efficiency of decellularized cartilage extracellular matrix (ECM) for the treatment of osteoarthritis (OA). We propose a series of post-decellularization procedures to overcome the current shortcomings such as low mechanical strength and poor bioactivity to improve decellularized ECM scaffold towards much more efficient and higher integration.

The Challenge in Using Mesenchymal Stromal Cells for Recellularization of Decellularized Cartilage

Some decellularized musculoskeletal extracellular matrices (ECM)s derived from tissues such as bone, tendon and fibrocartilaginous meniscus have already been clinical use for tissue reconstruction. Repair of articular cartilage with its unique zonal ECM architecture and composition is still an unsolved problem, and the question is whether allogenic or xenogeneic decellularized cartilage ECM could serve as a biomimetic scaffold for this purpose.Hence, this survey outlines the present state of preparing decellularized cartilage ECM-derived scaffolds or composites for reconstruction of different cartilage types and of reseeding it particularly with mesenchymal stromal cells (MSCs).The preparation of natural decellularized cartilage ECM scaffolds hampers from the high density of the cartilage ECM and lacking interconnectivity of the rather small natural pores within it: the chondrocytes lacunae. Nevertheless, the reseeding of decellularized ECM scaffolds before implantation provided superior results compared with simply implanting cell-free constructs in several other tissues, but cartilage recellularization remains still challenging. Induced by cartilage ECM-derived scaffolds MSCs underwent chondrogenesis.Major problems to be addressed for the application of cell-free cartilage were discussed such as to maintain ECM structure, natural chemistry, biomechanics and to achieve a homogenous and stable cell recolonization, promote chondrogenic and prevent terminal differentiation (hypertrophy) and induce the deposition of a novel functional ECM. Some promising approaches were proposed including further processing of the decellularized ECM before recellularization of the ECM with MSCs, co-culturing of MSCs with chondrocytes and establishing bioreactor culture e.g. with mechanostimulation, flow perfusion pressure and lowered oxygen tension. Graphical Abstract Synopsis of tissue engineering approaches based on cartilage-derived ECM.

Chondral and osteochondral operative treatment in early osteoarthritis

In recent years treatment of early osteoarthritis came more and more into focus of orthopaedic research. In particular regenerative therapy options seem to have a high potential to fill the existing treatment gap for patients with early osteoarthritic changes. This article focuses on basic science, recent developments and available clinical data in the important field of operative regeneration procedures for treatment of chondral and osteochondral defects in early degenerative joints. It highlights current knowledge and perspectives of treatment options like microfracture, autologous or allogenous osteochondral transplantations and autologous chondrocyte transplantation. Further the role of biomaterials in a degenerative joint environment is illuminated. First clinical data of regenerative therapy in early osteoarthritis are encouraging to intensify research efforts in this important field. Future treatment perspectives for patients who suffer from early degenerative cartilage changes are discussed.