Bone regeneration using mesenchymal stem cells has several limitations. We investigated adipose-derived dedifferentiated fat (DFAT) cells as an alternative, and evaluated their cell proliferation rate, osteoblast differentiation, and bone regeneration ability in combination with activated platelet-rich plasma (aPRP). Rat DFATs and aPRP were isolated using ceiling culture and centrifugation, respectively. The cell proliferation rate was measured, and the cells were cultured in an osteoblast differentiation medium under varying concentrations of aPRP for 21 days and stained with Alizarin red. Gene expression was evaluated using real time polymerase chain reaction. Critical defects were implanted with DFAT seeded gelatin sponges under aPRP, and four weeks later, the bone regeneration ability was evaluated using micro-computed tomography and hematoxylin-eosin staining. The cell proliferation rate was significantly increased by the addition of aPRP. Alizarin red staining was positive 21 days after the start of induction, with significantly higher Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) expression levels than those in the controls. A 9 mm critical defect was largely closed (60.6%) after four weeks of gelatin sponge implantation with DFAT and aPRP. Therefore, materials combining DFAT cells and aPRP may be an effective approach for bone regeneration. Further research is needed to explore the long-term effects of these materials.

Mechanical and resorbable scaffolds are in high demand for stem cell-based regenerative medicine, to treat refractory bone defects in craniofacial abnormalities and injuries. Multipotent progenitor cells, such as dedifferentiated fat (DFAT) cells, are prospective sources for regenerative therapies. Herein, we aimed to demonstrate that a composite gelatin sponge (α-TCP/GS) of alfa-tricalcium phosphate (α-TCP) mixed with gelatin scaffolds (GS), with/without DFATs, induced bone regeneration in a rat calvarial defect model in vivo. α-TCP/GS was prepared by mixing α-TCP and 2% GS using vacuum-heated methods. α-TCP/GS samples with/without DFATs were transplanted into the model. After 4 weeks of implantation, the samples were subjected to micro-computed tomography (μ-CT) and histological analysis. α-TCP/GS possessed adequate mechanical strength; α-TCP did not convert to hydroxyapatite upon contact with water, as determined by X-ray diffraction. Moreover, stable α-TCP/GS was formed by electrostatic interactions, and verified based on the infrared peak shifts. μ-CT analyses showed that bone formation was higher in the α-TCP/GS+ DFAT group than in the α-TCP/GS group. Therefore, the implantation of α-TCP/GS comprising DFAT cells enhanced bone regeneration and vascularization, demonstrating the potential for healing critical-sized bone defects.

Background: Glycation, a non-enzymatic reaction between sugars and biomolecules, leads to the formation of advanced glycation end-products (AGEs), which are implicated in the progression of chronic diseases. Connarus ruber (Poepp.) Planch (C. ruber), a traditional medicinal plant used for diabetes, has shown anti-glycation activity. This study aimed to identify the active components in C. ruber extract and elucidate their anti-glycation mechanisms. Methods: Using NMR and LC-MS analyses, we identified epicatechin and procyanidin A2 as major polyphenolic constituents. Collagen glycation assays were performed to evaluate the inhibitory effects of these compounds on fructose- and glyceraldehyde (GA)-induced glycation. Additionally, their cytoprotective effects were assessed using GA-induced cytotoxicity assays in dental pulp stem cells (DPSCs). Results: Both epicatechin and procyanidin A2 inhibited fructose- and GA-induced glycation in a dose-dependent manner, showing greater efficacy than aminoguanidine. Furthermore, these compounds significantly alleviated GA-induced cytotoxicity in DPSCs. Conclusions: These findings suggest that epicatechin and procyanidin A2 are candidate contributors to the anti-glycation and cytoprotective effects of C. ruber. The results support the potential of C. ruber extract as a source of therapeutic agents for glycation-related diseases and for enhancing stem cell viability.

Temporomandibular joint osteoarthritis (TMJ-OA) involves inflammation and degeneration of mandibular condylar cartilage and subchondral bone. Dedifferentiated fat cells (DFATs) were established from buccal fat pad tissue obtained from a single human donor. We examined the effects of DFAT-derived extracellular vesicle preparations (DFAT-EVs) on inflammatory macrophage responses in vitro and disease-related outcomes in TMJ-OA in vivo. DFAT-EVs were applied to lipopolysaccharide- and interferon-γ-stimulated RAW264.7 macrophages and administered intra-articularly in rats with monosodium iodoacetate-induced TMJ-OA. Fluorescence signals from labeled DFAT-EVs were observed in RAW264.7 cells. DFAT-EVs reduced nitric oxide production and modulated nitric oxide synthase 2, interleukin (IL)-1β, IL-6, IL-10, IL-4, and tumor necrosis factor-α responses, although effects varied among inflammatory mediators. Head withdrawal threshold was significantly higher in the DFAT-EVs group than in the OA group at several time points in the 6-week cohort, but not in the 4-week cohort. Administration of DFAT-EVs attenuated the reduction in mandibular condylar bone volume fraction and was associated with preservation of cartilage architecture and matrix. Osteoarthritis Research Society International scores were significantly lower in the DFAT-EVs group than in the OA group at 4 weeks but not at 6 weeks. These in vitro and in vivo findings support further evaluation of DFAT-EVs for TMJ-OA.