Harnessing Dental Stem Cell Immunoregulation Using Cell-Laden Biomaterials

Insights and Advancements in Periodontal Tissue Engineering and Bone Regeneration

The regeneration of periodontal bone defects continues to be an essential therapeutic concern in dental biomaterials. Numerous biomaterials have been utilized in this sector so far. However, the immune response and vascularity in defect regions may be disregarded when evaluating the effectiveness of biomaterials for bone repair. Among several regenerative treatments, the most recent technique of in situ tissue engineering stands out for its ability to replicate endogenous restorative processes by combining scaffold with particular growth factors. Regenerative medicine solutions that combine biomaterials/scaffolds, cells, and bioactive substances have attracted significant interest, particularly for bone repair and regeneration. Dental stem cells (DSCs) share the same progenitor and immunomodulatory properties as other types of MSCs, and because they are easily isolable, they are regarded as desirable therapeutic agents in regenerative dentistry. Recent research has demonstrated that DSCs sown on newly designed synthetic bio-material scaffolds preserve their proliferative capacity while exhibiting increased differentiation and immuno-suppressive capabilities. As researchers discovered how short peptide sequences modify the adhesion and proliferative capacities of scaffolds by activating or inhibiting conventional osteogenic pathways, the scaffolds became more effective at priming MSCs. In this review, the many components of tissue engineering applied to bone engineering will be examined, and the impact of biomaterials on periodontal regeneration and bone cellular biology/molecular genetics will be addressed and updated.

Macrophage Polarization Dynamics in Biomaterials: Implications for in Vitro Wound Healing

The interaction between biomaterials and the immune system plays a pivotal role in determining the success or failure of implantable devices. Macrophages, as key orchestrators of immune responses, exhibit diverse reactions that influence tissue integration or lead to implant failure. This study focuses on unraveling the intricate relationship between macrophage phenotypes and biomaterials, specifically hydrogels, by employing THP-1 cells as a model. Through a comprehensive investigation using polysaccharide, polymer, and protein-based hydrogels, our research sheds light on how the properties of hydrogels influence macrophage polarization. Phenotypic observations, biochemical assays, surface marker expression, and gene expression profiles collectively demonstrate the differential macrophage polarization abilities of polysaccharide-, polymer-, and protein-based hydrogels. Moreover, our indirect coculture studies reveal that hydrogels fostering M2 polarization exhibit exceptional wound-healing capabilities. These findings highlight the crucial role of the hydrogel microenvironment in adjusting macrophage polarization, offering a fresh avenue for refining biomaterials to bolster advantageous immune responses and improve tissue integration. This research contributes valuable insights for designing biomaterials with tailored properties that can guide macrophage behavior, ultimately improving the overall success of implantable devices.

[Advances in Molecular Regulatory Mechanisms of Jaw Repair and Reconstruction]

Jawbone injuries resulting from trauma, diseases, and surgical resections are commonly seen in clinical practice, necessitating precise and effective strategies for repair and reconstruction to restore both function and aesthetics. The precise and effective repair and the reconstruction of jawbone injuries pose a significant challenge in the field of oral and maxillofacial surgery, owing to the unique biomechanical characteristics and physiological functions of the jawbone. The natural repair process following jawbone injuries involves stages such as hematoma formation, inflammatory response, ossification, and bone remodeling. Bone morphogenetic proteins (BMPs), transforming growth factor beta (TGF-β), vascular endothelial growth factor (VEGF), and other growth factors play crucial roles in promoting jawbone regeneration. Cytokines such as interleukins and tumor necrosis factor play dual roles in regulating inflammatory response and bone repair. In recent years, significant progress in molecular biology research has been made in the field of jawbone repair and reconstruction. Tissue engineering technologies, including stem cell therapy, bioactive scaffolds, and growth factor delivery systems, have found important applications in jawbone repair. However, the intricate molecular regulatory mechanisms involved in the complex jawbone repair and reconstruction methods are not fully understood and still require further research. Future research directions will be focused on the precise control of these molecular processes and the development of more efficient combination therapeutic strategies to promote the effective and functional reconstruction of the jawbone. This review aims to examine the latest findings on the molecular regulatory mechanisms of the repair and reconstruction of jawbone injuries and the therapeutic strategies. The conclusions drawn in this article provide a molecular-level understanding of the repair of jawbone injuries and highlight potential directions for future research.

Delivery of dental pulp stem cells by an injectable ROS-responsive hydrogel promotes temporomandibular joint cartilage repair via enhancing anti-apoptosis and regulating microenvironment

Temporomandibular joint (TMJ) cartilage repair poses a considerable clinical challenge, and tissue engineering has emerged as a promising solution. In this study, we developed an injectable reactive oxygen species (ROS)-responsive multifunctional hydrogel (RDGel) to encapsulate dental pulp stem cells (DPSCs/RDGel in short) for the targeted repair of condylar cartilage defect. The DPSCs/RDGel composite exhibited a synergistic effect in the elimination of TMJ OA (osteoarthritis) inflammation via the interaction between the hydrogel component and the DPSCs. We first demonstrated the applicability and biocompatibility of RDGel. RDGel encapsulation could enhance the anti-apoptotic ability of DPSCs by inhibiting P38/P53 mitochondrial apoptotic signal in vitro. We also proved that the utilization of DPSCs/RDGel composite effectively enhanced the expression of TMJOA cartilage matrix and promoted subchondral bone structure in vivo. Subsequently, we observed the synergistic improvement of DPSCs/RDGel composite on the oxidative stress microenvironment of TMJOA and its regulation and promotion of M2 polarization, thereby confirmed that M2 macrophages further promoted the condylar cartilage repair of DPSCs. This is the first time application of DPSCs/RDGel composite for the targeted repair of TMJOA condylar cartilage defects, presenting a novel and promising avenue for cell-based therapy.

Dental-derived stem cells in tissue engineering: the role of biomaterials and host response

Dental-derived stem cells (DSCs) are attractive cell sources due to their easy access, superior growth capacity and low immunogenicity. They can respond to multiple extracellular matrix signals, which provide biophysical and biochemical cues to regulate the fate of residing cells. However, the direct transplantation of DSCs suffers from poor proliferation and differentiation toward functional cells and low survival rates due to local inflammation. Recently, elegant advances in the design of novel biomaterials have been made to give promise to the use of biomimetic biomaterials to regulate various cell behaviors, including proliferation, differentiation and migration. Biomaterials could be tailored with multiple functionalities, e.g., stimuli-responsiveness. There is an emerging need to summarize recent advances in engineered biomaterials-mediated delivery and therapy of DSCs and their potential applications. Herein, we outlined the design of biomaterials for supporting DSCs and the host response to the transplantation.

Therapeutic Potential of Oral-Derived Mesenchymal Stem Cells in Retinal Repair

The retina has restricted regeneration ability to recover injured cell layer because of reduced production of neurotrophic factors and increased inhibitory molecules against axon regrowth. A diseased retina could be regenerated by repopulating the damaged tissue with functional cell sources like mesenchymal stem cells (MSCs). The cells are able to release neurotrophic factors (NFs) to boost axonal regeneration and cell maintenance. In the current study, we comprehensively explore the potential of various types of stem cells (SCs) from oral cavity as promising therapeutic options in retinal regeneration. The oral MSCs derived from cranial neural crest cells (CNCCs) which explains their broad neural differentiation potential and secret rich NFs. They are comprised of dental pulp SCs (DPSCs), SCs from exfoliated deciduous teeth (SHED), SCs from apical papilla (SCAP), periodontal ligament-derived SCs (PDLSCs), gingival MSCs (GMSCs), and dental follicle SCs (DFSCs). The Oral MSCs are becoming a promising source of cells for cell-free or cell-based therapeutic approach to recover degenerated retinal. These cells have various mechanisms of action in retinal regeneration including cell replacement and the paracrine effect. It was demonstrated that they have more neuroprotective and neurotrophic effects on retinal cells than immediate replacement of injured cells in retina. This could be the reason that their therapeutic effects would be weakened over time. It can be concluded that neuronal and retinal regeneration through these cells is most likely due to their NFs that dramatically suppress oxidative stress, inflammation, and apoptosis. Although, oral MSCs are attractive therapeutic options for retinal injuries, more preclinical and clinical investigations are required.

The Osteogenic Role of Biomaterials Combined with Human-Derived Dental Stem Cells in Bone Tissue Regeneration

The use of stem cells in regenerative medicine had great potential for clinical applications. However, cell delivery strategies have critical importance in stimulating the differentiation of stem cells and enhancing their potential to regenerate damaged tissues. Different strategies have been used to investigate the osteogenic potential of dental stem cells in conjunction with biomaterials through in vitro and in vivo studies. Osteogenesis has a broad implication in regenerative medicine, particularly for maxillofacial defects. This review summarizes some of the most recent developments in the field of tissue engineering using dental stem cells.

Stem cells and common biomaterials in dentistry: a review study

Stem cells exist as normal cells in embryonic and adult tissues. In recent years, scientists have spared efforts to determine the role of stem cells in treating many diseases. Stem cells can self-regenerate and transform into some somatic cells. They would also have a special position in the future in various clinical fields, drug discovery, and other scientific research. Accordingly, the detection of safe and low-cost methods to obtain such cells is one of the main objectives of research. Jaw, face, and mouth tissues are the rich sources of stem cells, which more accessible than other stem cells, so stem cell and tissue engineering treatments in dentistry have received much clinical attention in recent years. This review study examines three essential elements of tissue engineering in dentistry and clinical practice, including stem cells derived from the intra- and extra-oral sources, growth factors, and scaffolds.

RGD-Modified Alginate-GelMA Hydrogel Sheet Containing Gingival Mesenchymal Stem Cells: A Unique Platform for Wound Healing and Soft Tissue Regeneration

Soft tissue reconstruction has remained a major clinical challenge in dentistry and regenerative medicine. Although current methods have shown partial success, there are several disadvantages associated with these approaches. Gingival mesenchymal stem cells (GMSCs) can be simply obtained in the oral cavity for soft tissue augmentation. Regenerative potential of mesenchymal stem cells (MSCs) encapsulated in hydrogels is well documented. Here, an alginate-gelatin methacrylate (GelMA) hydrogel formulation is developed encapsulating GMSCs within the developed hydrogel. The results confirm that the encapsulated MSCs remain viable within the hydrogel with enhanced collagen deposition. An excisional wound model in mice is utilized to evaluate the in vivo functionality of the GMSC-hydrogel construct for wound healing and soft tissue regeneration. The histology and immunofluorescence analyses confirm the effectiveness of the GMSC-hydrogel in expediting wound healing via enhancing angiogenesis and suppressing local proinflammatory cytokines. Altogether, the findings demonstrate that GMSCs encapsulated in an engineered hydrogel sheet based on alginate and GelMA can be used to expedite wound healing and soft tissue regeneration, with potential applications in plastic and reconstructive surgery as well as dentistry.

Doxycycline-Doped Polymeric Membranes Induced Growth, Differentiation and Expression of Antigenic Phenotype Markers of Osteoblasts

Polymeric membranes are employed in guided bone regeneration (GBR) as physical barriers to facilitate bone in-growth. A bioactive and biomimetic membrane with the ability to participate in the healing and regeneration of the bone is necessary. The aim of the present study was to analyze how novel silicon dioxide composite membranes functionalized with zinc or doxycycline can modulate the osteoblasts' proliferation, differentiation, and expression of selected antigenic markers related to immunomodulation. Nanostructured acrylate-based membranes were developed, blended with silica, and functionalized with zinc or doxycycline. They were subjected to MG63 osteoblast-like cells culturing. Proliferation was assessed by MTT-assay, differentiation by evaluating the alkaline phosphatase activity by a spectrophotometric method and antigenic phenotype was assessed by flow cytometry for selected markers. Mean comparisons were conducted by one-way ANOVA and Tukey tests (p < 0.05). The blending of silica nanoparticles in the tested non-resorbable polymeric scaffold improved the proliferation and differentiation of osteoblasts, but doxycycline doped scaffolds attained the best results. Osteoblasts cultured on doxycycline functionalized membranes presented higher expression of CD54, CD80, CD86, and HLA-DR, indicating a beneficial immunomodulation activity. Doxycycline doped membranes may be a potential candidate for use in GBR procedures in several challenging pathologies, including periodontal disease.