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Conventional methods of stem cell therapy for tissue regeneration often face challenges, such as poor cell viability and integration posttransplantation. To address this, we proposed transplanting cells within synthetic microenvironments that maintain viability, cell phenotype, support extracellular matrix (ECM) secretion, and promote differentiation to enhance the regeneration of damaged host tissue. This hypothesis was tested in dental tissue regeneration using dental pulp stem cell‐laden microcarriers (MCs) mixed in a gelatin methacrylate (GelMA) hydrogel as a delivery system. The combination of MCs and GelMA exhibited similar physical properties and favorable biological properties compared to GelMA alone. Specifically, cell‐laden MC mixed into GelMA enhanced cell proliferation and ECM secretion and maintained a normal phenotype. Notably, MC‐modified GelMA amplified odontogenic differentiation, mineralization, and vascular endothelial growth factor release. Moreover, the storage of MC‐modified GelMA showed no detrimental effects on its injection force, cell viability, and mineralization potential, which demonstrates that the composite hydrogel is a promising injectable vehicle for therapeutic stem cell delivery. This strategy may be broadly applied to various tissues and organ systems, in which the provision and instruction of a cell population to participate in regeneration may be clinically useful. [ABSTRACT FROM AUTHOR]

Background: The Langerhans cells (LCs) are dendritic cells (DCs) which belong to the group of antigen presenting cells (APCs). Their function is to recognize the antigen, capture it, and present it to the T lymphocytes; thus initiating an early immune response. The antigen presenting functional LCs may play an important part in initiation and development of gingivitis. The aim of this study was to analyze the density, intraepithelial distribution, and morphology of LCs in gingival epithelium among different age groups with chronic gingivitis and to compare it with that of normal gingiva. Materials and Methods: Immunohistochemistry (IHC) was performed to study LCs in normal gingival epithelium (n = 10) and gingival epithelium in chronic gingivitis (n = 30) using anti-CD1a antibody. Mann Whitney U test was performed to compare the density of LCs in normal gingiva with chronic gingivitis. The distribution of LCs in various layers of the epithelium within the three age groups was analyzed using Kruskal-Wallis test. P value less than 0.05 was considered as significant. Results: The density of LCs in chronic gingivitis was significantly higher then that of normal gingiva. Comparing different age groups, the younger individuals had more number of LCs which were located in the superficial layers of gingival epithelium. In chronic gingivitis, higher number of LCs were located in deeper layers when compared with that of normal gingiva. Three morphological types of CD1a positive LCs were observed in normal gingiva, out of which the density of LCs with branched dendritic processes was highest in normal gingiva. Conclusion: The LCs showed variable number, location, and morphology which indicated their adaptation for function in chronic gingivitis.

Background and Objectives: Ageing is associated with an impaired cellular function that can affect tissue architecture and wound healing in gingival and periodontal tissues. However, the impact of oral fibroblast ageing on the structural organization of the extracellular matrix (ECM) proteins is poorly understood. Hence, in this study, we investigated the impact of cellular ageing of oral fibroblasts on the production and structural organization of collagen and other ECM proteins. Methods: Oral fibroblasts were serially subcultured, and replicative cellular senescence was assessed using population doubling time, Ki67 counts and expression of P21WAFI. The production and structural organization of ECM proteins were assessed at early (young‐oFB) and late (aged‐oFB) passages. The thickness and pattern of collagen produced by live cultures of young‐ and aged‐oFB were assessed using a label‐free and non‐invasive second harmonic generation (SHG)‐based multiphoton imaging. Expression of other ECM proteins (fibronectin, fibrillin, collagen‐IV and laminins) was evaluated using immunocytochemistry and confocal microscopy‐based depth profile analysis. Results: Aged‐oFB displayed a higher population doubling time, lower Ki67+ cells and higher expression of P21WAFI indicative of slower proliferation rate and senescence phenotype. SHG imaging demonstrated that young‐oFB produced a thick, interwoven network of collagen fibres, while the aged‐oFB produced thin and linearly organized collagen fibres. Similarly, analysis of immunostained cultures showed that young‐oFB produced a rich, interwoven mesh of fibronectin, fibrillin and collagen‐IV fibres. In contrast, the aged‐oFB produced linearly organized fibronectin, fibrillin and collagen‐IV fibres. Lastly, there was no observable difference in production and organization of laminins among the young‐ and aged‐oFB. Conclusion: Our results suggest that oral fibroblast ageing impairs ECM production and more importantly the organization of ECM fibres, which could potentially impair wound healing in the elderly. [ABSTRACT FROM AUTHOR]