Biomaterials combined with ADSCs for bone tissue engineering: current advances and applications

Enhanced osteogenic and angiogenic capabilities of adipose-derived stem cells in fish collagen scaffolds for treatment of femoral head osteonecrosis

Osteonecrosis of the femoral head (ONFH) is a debilitating condition that often leads to femoral head collapse due to insufficient blood supply and impaired bone regeneration. However, effective treatment options for this condition are limited. This study explored a novel fish collagen (FC) scaffold combined with adipose-derived stem cells (ADSCs) to enhance osteogenesis and angiogenesis in ONFH. ADSCs were isolated and cultured on FC scaffolds to evaluate their biocompatibility and differentiation capacity. Osteogenic and angiogenic differentiation potentials were assessed in vitro, and the FC/ADSC combination was further evaluated in vivo using a rat model of ONFH. The molecular mechanisms were investigated via gene expression profiling and Hippo signaling pathway analysis. The FC scaffolds promoted ADSCs adhesion, proliferation, and migration without cytotoxicity. In vitro, FC/ADSCs significantly enhanced mineralization and capillary-like structure formation compared to the controls. FC/ADSCs improved bone regeneration and neovascularization in the femoral head in vivo, as confirmed by histological and immunohistochemical analyses. Mechanistically, the Hippo pathway is activated, increasing HIF-1α expression, which enhances osteogenic and angiogenic differentiation. FC scaffolds combined with ADSCs provide a promising therapeutic strategy for ONFH by facilitating bone regeneration and vascularization through the p-YAP/HIF-1α/VEGF axis. This scaffold-cell approach represents a potential advancement in ONFH treatment.

ACL injury management: a comprehensive review of novel biotherapeutics

The anterior cruciate ligament (ACL) is integral to the stability of the knee joint, serving to limit anterior tibial translation and regulate rotational movements. ACL injuries are among the most common and debilitating forms of knee trauma, often resulting in joint effusion, muscular atrophy, and diminished athletic capabilities. Despite the established efficacy of ACL reconstruction as the standard treatment, it is not uniformly successful. Consequently, there is a growing interest in novel biotherapeutic interventions as potential alternatives. This comprehensive review examines the latest advancements in ACL biotherapy, encompassing the application of hyaluronic acid, self-assembled short peptides, growth factors, stem cell therapy, gene therapy, platelet-rich plasma therapy, bone marrow aspirate concentrate cells, extracorporeal shock wave, electrical stimulation and cross bracing protocol. The collective aim of these innovative treatments is to facilitate the restoration of the ACL's native biological and biomechanical integrity, with the ultimate goal of enhancing clinical outcomes and the functional recovery of affected individuals.

Advancements in nanohydroxyapatite: synthesis, biomedical applications and composite developments

Nanohydroxyapatite (nHA) is distinguished by its exceptional biocompatibility, bioactivity and biodegradability, qualities attributed to its similarity to the mineral component of human bone. This review discusses the synthesis techniques of nHA, highlighting how these methods shape its physicochemical attributes and, in turn, its utility in biomedical applications. The versatility of nHA is further enhanced by doping with biologically significant ions like magnesium or zinc, which can improve its bioactivity and confer therapeutic properties. Notably, nHA-based composites, incorporating metal, polymeric and bioceramic scaffolds, exhibit enhanced osteoconductivity and osteoinductivity. In orthopedic field, nHA and its composites serve effectively as bone graft substitutes, showing exceptional osteointegration and vascularization capabilities. In dentistry, these materials contribute to enamel remineralization, mitigate tooth sensitivity and are employed in surface modification of dental implants. For cancer therapy, nHA composites offer a promising strategy to inhibit tumor growth while sparing healthy tissues. Furthermore, nHA-based composites are emerging as sophisticated platforms with high surface ratio for the delivery of drugs and bioactive substances, gradually releasing therapeutic agents for progressive treatment benefits. Overall, this review delineates the synthesis, modifications and applications of nHA in various biomedical fields, shed light on the future advancements in biomaterials research.

Stem Cells: Present Understanding and Prospects for Regenerative Dentistry

Regenerative medicine in dentistry focuses on repairing damaged oral tissues using advanced tools like stem cells, biomaterials, and tissue engineering (TE). Mesenchymal stem cells (MSCs) from dental sources, such as dental pulp and periodontal ligament, show significant potential for tissue regeneration due to their proliferative and differentiative abilities. This systematic review, following PRISMA guidelines, evaluated fifteen studies and identified effective strategies for improving dental, periodontal, and bone tissue regeneration through scaffolds, secretomes, and bioengineering methods. Key advancements include the use of dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs) to boost cell viability and manage inflammation. Additionally, pharmacological agents like matrine and surface modifications on biomaterials improve stem cell adhesion and promote osteogenic differentiation. By integrating these approaches, regenerative medicine and TE can optimize dental therapies and enhance patient outcomes. This review highlights the potential and challenges in this field, providing a critical assessment of current research and future directions.

Multi-site enhancement of osteogenesis: peptide-functionalized GelMA hydrogels with three-dimensional cultures of human dental pulp stem cells

Human dental pulp stem cells (hDPSCs) have demonstrated greater proliferation and osteogenic differentiation potential in certain studies compared to other types of mesenchymal stem cells, making them a promising option for treating craniomaxillofacial bone defects. However, due to low extracting concentration and long amplifying cycles, their access is limited and utilization rates are low. To solve these issues, the principle of bone-forming peptide-1 (BFP1) in situ chemotaxis was utilized for the osteogenic differentiation of hDPSCs to achieve simultaneous and synergistic osteogenesis at multiple sites. BFP1-functionalized gelatin methacryloyl hydrogel provided a 3D culture microenvironment for stem cells. The experimental results showed that the 3D composite hydrogel scaffold constructed in this study increased the cell spread area by four times compared with the conventional GelMA scaffold. Furthermore, the problems of high stem cell dosage and low rate of utilization were alleviated by orchestrating the programmed proliferation and osteogenic differentiation of hDPSCs. In vivo, high-quality repair of critical bone defects was achieved using hDPSCs extracted from a single tooth, and multiple 'bone island'-like structures were successfully observed that rapidly induced robust bone regeneration. In conclusion, this study suggests that this kind of convenient, low-cost, island-like osteogenesis strategy involving a low dose of hDPSCs has great potential for repairing craniomaxillofacial critical-sized bone defects.

Toll-like receptor activation regulates the paracrine effect of adipose-derived mesenchymal stem cells on reversing osteoarthritic phenotype of chondrocytes

BACKGROUND

The therapeutic efficacy of intra-articular mesenchymal stem cells (MSCs) injection for patients with osteoarthritis (OA) currently exhibits inconsistency, and the underlying mechanism remains elusive. It has been postulated that the immunomodulatory properties and paracrine activity of MSCs might be influenced by the inflammatory micro-environment within osteoarthritic joints, potentially contributing to this observed inconsistency.

METHODS

Adipose-derived MSCs (ADSCs) were isolated from SD rats and pre-treated with Toll-like receptor 3 (TLR3) agonist Poly I:C or Toll-like receptor 4 (TLR4) agonist LPS. The pre-treated ADSCs were then co-cultured with IL-1β-induced osteoarthritic chondrocytes using a Transwell system to analyze the paracrine effect of ADSCs on reversing the osteoarthritic phenotype of chondrocytes.

RESULTS

RT-PCR and Western blot analysis revealed that Poly I:C and LPS pre-treatments up-regulated the expression of IL-10 and IL-6 in ADSCs, respectively. Furthermore, only Poly I:C-preconditioned ADSCs significantly promoted proliferation while inhibiting apoptosis in IL-1β-treated chondrocytes. Additionally, Poly I:C-preconditioned ADSCs downregulated MMP13 expression while upregulating aggrecan and collagen II expression levels in IL-1β-treated chondrocytes.

CONCLUSIONS

TLR3 activation polarizes ADSCs into an immunomodulatory phenotype distinct from TLR4 activation, exerting differential effects on reversing the osteoarthritic phenotype of chondrocytes; thus indicating that MSCs' paracrine effect regulated by TLRs signaling impacts the efficacy of intra-articular MSCs injection.

Application of metal-organic frameworks-based functional composite scaffolds in tissue engineering

With the rapid development of materials science and tissue engineering, a variety of biomaterials have been used to construct tissue engineering scaffolds. Due to the performance limitations of single materials, functional composite biomaterials have attracted great attention as tools to improve the effectiveness of biological scaffolds for tissue repair. In recent years, metal-organic frameworks (MOFs) have shown great promise for application in tissue engineering because of their high specific surface area, high porosity, high biocompatibility, appropriate environmental sensitivities and other advantages. This review introduces methods for the construction of MOFs-based functional composite scaffolds and describes the specific functions and mechanisms of MOFs in repairing damaged tissue. The latest MOFs-based functional composites and their applications in different tissues are discussed. Finally, the challenges and future prospects of using MOFs-based composites in tissue engineering are summarized. The aim of this review is to show the great potential of MOFs-based functional composite materials in the field of tissue engineering and to stimulate further innovation in this promising area.