Integrated gradient tissue-engineered osteochondral scaffolds: Challenges, current efforts and future perspectives.

The osteochondral defect repair has been most extensively studied due to the rising demand for new therapies to diseases such as osteoarthritis. Tissue engineering has been proposed as a promising strategy to meet the demand of simultaneous regeneration of both cartilage and subchondral bone by constructing integrated gradient tissue-engineered osteochondral scaffold (IGTEOS). This review brought forward the main challenges of establishing a satisfactory IGTEOS from the perspectives of the complexity of physiology and microenvironment of osteochondral tissue, and the limitations of obtaining the desired and required scaffold. Then, we comprehensively discussed and summarized the current tissue-engineered efforts to resolve the above challenges, including architecture strategies, fabrication techniques and in vitro/in vivo evaluation methods of the IGTEOS. Especially, we highlighted the advantages and limitations of various fabrication techniques of IGTEOS, and common cases of IGTEOS application. Finally, based on the above challenges and current research progress, we analyzed in details the future perspectives of tissue-engineered osteochondral construct, so as to achieve the perfect reconstruction of the cartilaginous and osseous layers of osteochondral tissue simultaneously. This comprehensive and instructive review could provide deep insights into our current understanding of IGTEOS.

The effect of carbon nanotubes on osteogenic functions of adipose-derived mesenchymal stem cells in vitro and bone formation in vivo compared with that of nano-hydroxyapatite and the possible mechanism.

It has been well recognized that the development and use of artificial materials with high osteogenic ability is one of the most promising means to replace bone grafting that has exhibited various negative effects. The biomimetic features and unique physiochemical properties of nanomaterials play important roles in stimulating cellular functions and guiding tissue regeneration. But efficacy degree of some nanomaterials to promote specific tissue formation is still not clear. We hereby comparatively studied the osteogenic ability of our treated multi-walled carbon nanotubes (MCNTs) and the main inorganic mineral component of natural bone, nano-hydroxyapatite (nHA) in the same system, and tried to tell the related mechanism. In vitro culture of human adipose-derived mesenchymal stem cells (HASCs) on the MCNTs and nHA demonstrated that although there was no significant difference in the cell adhesion amount between on the MCNTs and nHA, the cell attachment strength and proliferation on the MCNTs were better. Most importantly, the MCNTs could induce osteogenic differentiation of the HASCs better than the nHA, the possible mechanism of which was found to be that the MCNTs could activate Notch involved signaling pathways by concentrating more proteins, including specific bone-inducing ones. Moreover, the MCNTs could induce ectopic bone formation in vivo while the nHA could not, which might be because MCNTs could stimulate inducible cells in tissues to form inductive bone better than nHA by concentrating more proteins including specific bone-inducing ones secreted from M2 macrophages. Therefore, MCNTs might be more effective materials for accelerating bone formation even than nHA.

Applications of Graphene and Its Derivatives in Bone Repair: Advantages for Promoting Bone Formation and Providing Real-Time Detection, Challenges and Future Prospects.

During continuous innovation in the preparation, characterization and application of various bone repair materials for several decades, nanomaterials have exhibited many unique advantages. As a kind of representative two-dimensional nanomaterials, graphene and its derivatives (GDs) such as graphene oxide and reduced graphene oxide have shown promising potential for the application in bone repair based on their excellent mechanical properties, electrical conductivity, large specific surface area (SSA) and atomic structure stability. Herein, we reviewed the updated application of them in bone repair in order to present, as comprehensively, as possible, their specific advantages, challenges and current solutions. Firstly, how their advantages have been utilized in bone repair materials with improved bone formation ability was discussed. Especially, the effects of further functionalization or modification were emphasized. Then, the signaling pathways involved in GDs-induced osteogenic differentiation of stem cells and immunomodulatory mechanism of GDs-induced bone regeneration were discussed. On the other hand, their applications as contrast agents in the field of bone repair were summarized. In addition, we also reviewed the progress and related principles of the effects of GDs parameters on cytotoxicity and residues. At last, the future research was prospected.

Nanocomposites for the delivery of bioactive molecules in tissue repair: vital structural features, application mechanisms, updated progress and future perspectives.

In recent years, nanocomposites have attracted great attention in tissue repair as carriers for bioactive molecule delivery due to their biochemical and nanostructural similarity to that of physiological tissues, and controlled delivery of bioactive molecules. In this review, we aim to comprehensively clarify how the applications of nanocomposites for bioactive molecule delivery in tissue repair are achieved by focusing on the following aspects: (1) vital structural features (size, shape, pore, etc.) of nanocomposites that have crucial effects on the biological properties and function of bioactive molecule-delivery systems, (2) delivery performance of bioactive molecules possessing high entrapment efficiency of bioactive molecules and good controlled- and sustained-release of bioactive molecules, (3) application mechanisms of nanocomposites to deliver and release bioactive molecules in tissue repair, (4) updated research progress of nanocomposites for bioactive molecule delivery in hard and soft tissue repair, and (5) future perspectives in the development of bioactive molecule-delivery systems based on nanocomposites.

Cemented versus uncemented total knee arthroplasty in younger patients: A protocol of retrospective cohort trial.

BACKGROUND: Recently, controversy still exists regarding the clinical effects of cemented or cementless technique in young patients in total knee arthroplasty (TKA). In this context, the present study aimed to determine the functional outcomes and clinical reliability of cementless components versus those of conventional cemented components for young patients in primary TKA. METHODS: A retrospective review of primary TKAs performed with cementless or cemented fixation between May 2010 and February 2019 was conducted with Institutional Review Board approval. All cases were performed by a single surgeon. Institutional review board approval was obtained prior to conducting chart review and analysis. The primary outcome compared between the 2 fixation groups was the rate of postoperative complications and revision related to TKA, occurring at any point in follow-up. Secondary outcome measures included surgical time, Oxford Knee Score, range of motion, and radiographic outcomes such as progressive radiolucent lines, osteolysis, or component migration. RESULTS: We were able to directly compare the outcomes of cemented versus cementless techniques and might reveal a better technique in TKA. TRIAL REGISTRATION: This study protocol was registered in Research Registry (researchregistry5459).

BMP7 can promote osteogenic differentiation of human periosteal cells in vitro.

To study and evaluate BMP7s functions in osteogenic differentiation of human periosteal cells in vitro. Human periosteal cells from adult tibia were collected and cultured as experimental samples. BMP7 was used to induce periosteal cells in the experiment group with common osteogenic medium. The proliferative activity of periosteal cells was detected by CCK-8. The potentials of osteogenic differentiation were demonstrated as follows: (1) realtime-PCR and ELISA to confirm the expression of the OC, ALP and OPN, (2) Colorimetry, ALP staining and Von Kossa staining were performed to identify ALP activity, ALP expression and calcium nodules, respectively. Based on the significant different expression of OC, ALP and OPN, BMP7 ability of osteogenic differentiation can be identified. ALP activity detection, calcium nodules staining and toluidine staining also provide the power evidence to support BMP7 can promote osteogenic differentiation of human periosteal cells in vitro. To human periosteal cells, BMP7 is a good inducer for osteogenic differentiation. Therefore, it's maybe a potential tool for clinical application.