José Ricardo Muniz Ferreira

Periosteum-derived osteo-like cells (PDOCs) and their lyophilized conditioned medium are promising tools for bone regeneration, but their therapeutic potential for osteoporosis remains unknown. This study evaluated the effects of PDOCs and their lyophilized conditioned medium on bone mineralization and microarchitecture in ovariectomized rats. Eighteen ovariectomized rats (six animals per group) received PBS (negative control group—NCG), PDOCs (periosteum osteo-like cell group—POCG), or a PDOC lyophilized conditioned medium (periosteum osteo-like lyophilized conditioned medium Group—POCM). All animals were euthanized after 42 days, and the femurs were submitted to microCT and histomorphometric analysis to determine: (1) thickness of the cortical bone; (2) number of trabeculae; (3) percentage of mineralized tissue; (4) percentage of collagen fibers; and (5) percentage of medullary spaces. The thickness of the cortical bone was statistically higher in POCG and POCM than in NCG animals (p < 0.05). The trabecular number was higher in POCG and POCM than in NCG rats (p < 0.05). The percentage of mineralized tissue was higher in POCG and POCM than in NCG animals (p < 0.05). No statistically significant difference was observed for collagen fibers or percentage of medullary spaces among groups. The use of PDOCs and their lyophilized conditioned medium improved cortical bone thickness, the number of trabeculae, and the level of mineralized tissue, suggesting that tissue engineering approaches with PDOCs and their lyophilized conditioned medium have potential use for the treatment of osteoporosis.

Periosteum-derived osteo-like cells (PDOCs) and their lyophilized conditioned medium are promising tools for bone regeneration, but their therapeutic potential for osteoporosis remains unknown. This study evaluated the effects of PDOCs and their lyophilized conditioned medium on bone mineralization and microarchitecture in ovariectomized rats. Eighteen ovariectomized rats (6 animals per group) received PBS (Negative Control Group–NCG); PDOCs (Periosteum Osteolike Cell Group - POCG), or PDOCs lyophilized conditioned medium (Periosteum Osteolike lyophilized conditioned medium Group - POCM). All animals were euthanized after 42 days, and the femurs submitted to microCT and histomorphometric analysis to determine: (1) thickness of the cortical bone; (2) number of trabeculae; (3) percentage of mineralized tissue; (4) percentage of collagen fibers; and (5) percentage of medullary spaces. The thickness of the cortical bone was statistically higher in POCG and POCM than in NCG animals (p<0.05). The trabecular number was higher in POCG and POCM than in NCG rats (p<0.05). The percentage of mineralized tissue was higher in POCG and POCM than in NCG animals (p<0.05), and no statistically significant difference was observed for collagen fibers and percentage of medullary spaces among groups. The use of PDOCs and their lyophilized conditioned medium improved cortical bone thickness, the number of trabeculae and the level of mineralized tissue, suggesting that tissue engineering approaches with PDOC and their lyophilized conditioned medium have potential use for the treatment of osteoporosis.

Periodontal diseases and temporomandibular disorders are characterized by chronic inflammation and progressive destruction of supporting tissues, leading to functional and aesthetic impairments. In this context, regenerative dentistry has increasingly focused on minimally invasive strategies capable of restoring tissue structure and function. Mesenchymal stem cells (MSCs) have emerged as central elements of regenerative approaches due to their multilineage differentiation potential, immunomodulatory properties, and paracrine activity. Concurrently, low-level laser therapy (LLLT), also known as photobiomodulation (PBM), has gained relevance as a non-invasive modality capable of modulating cellular behavior, inflammation, and tissue repair. This scoping review synthesizes current evidence on the combined application of MSCs and light-based therapies, emphasizing how laser-mediated metabolic modulation influences MSC fate and regenerative outcomes. Overall, the findings demonstrate that PBM enhances MSC proliferation, viability, migration, and lineage-specific differentiation, osteogenic, chondrogenic, angiogenic, and adipogenic, in a wavelength-, energy-, and dose-dependent manner. Emerging evidence indicates that the mitochondrial function represents a critical mechanistic link between laser irradiation and MSC responses. Photobiomodulation modulates mitochondrial bioenergetics primarily through activation of cytochrome c oxidase, resulting in increased ATP production, controlled reactive oxygen species signaling, and regulation of key transcription factors such as RUNX2, Sox9, and PPARγ. These mitochondrial-mediated effects act as metabolic checkpoints that integrate microenvironmental cues with lineage commitment and tissue-specific regeneration. Collectively, the data support the concept that precise modulation of mitochondrial activity by PBM optimizes the regenerative potential of MSCs. A deeper understanding of the interplay between laser strategies and parameters, mitochondrial metabolism, MSC source, and the cellular microenvironment is essential for the development of safe, effective, and reproducible regenerative protocols in dentistry and regenerative medicine.

This study aimed to evaluate periosteum-derived mesenchymal stem cells (P-MSCs) cultured under simulated microgravity (SMG) conditions. P-MSCs were induced toward osteogenic differentiation and then exposed to SMG for up to 48 h. As a control, P-MSCs were maintained under identical conditions but without SMG exposure. Cell viability, osteogenesis-related analytes, and gene expression were analyzed at 3, 24 and 48 h. Cell viability under SMG was lower after 3 h but was significantly higher after 24 h, with no difference at 48 h. There was a higher expression of pathways associated with inflammation at 3 h, which was attenuated by 24 h and neutralized at 48 h. P-MSCs under SMG demonstrated three characteristics in at least one timepoint, which supports a pro-osteogenic signaling response: (1) higher osteoprotegerin levels; (2) lower DKK1 and TNF levels; (3) upregulation of genes related to osteogenesis. Our data suggest that P-MSCs exhibit enhanced pro-osteogenic regulatory modulation in SMG.

Autogenous grafts remain the gold standard for repairing extensive maxillofacial bone defects, but their associated morbidity motivates the search for alternative strategies in tissue bioengineering. Deciduous dental pulp stem cells (DDPSCs) represent a promising cell source due to their accessibility, multipotency, and osteogenic potential, while nanostructured carbonated hydroxyapatite (cHA) microspheres exhibit biochemical similarity to bone mineral and favorable bioabsorption. This study investigated the osteogenic response induced by the association of DDPSCs with cHA in a rat calvaria critical-size defect model. DDPSCs were expanded, seeded onto cHA microspheres, and characterized in vitro prior to bilateral implantation in 12 Wistar rats, with each animal receiving cHA + DDPSC on the right defect and acellular cHA on the left. After 60 and 90 days, histological and histomorphometric analyses revealed new bone formation in both groups, predominantly from the defect margins toward the center. At 60 days, no significant difference in newly formed bone was observed between groups (p = 0.249). At 90 days, the DDPSC + cHA group demonstrated significantly greater bone formation compared with acellular cHA (median 40.70 vs. 11.10 histomorphometric points; p = 0.028) and significant reduction in connective tissue (p = 0.028). Complete scaffold resorption was observed in all DDPSC-treated defects at 90 days, whereas residual biomaterial persisted in the cHA group (p = 0.015), indicating progressive cHA resorption over time. These findings suggest that combining DDPSCs with cHA enhances bone regeneration and that this synthetic, bioabsorbable scaffold represents a promising strategy for future applications in bone tissue engineering.

The aim of this study is to validate a minimally invasive surgical procedure to harvest palate periosteum as a source of tissue for mesenchymal stromal/stem cells. We performed a standardized procedure to harvest the palate periosteum in ten subjects, which consisted of a 3 mm disposable punch and a Molt periosteal elevator to harvest a small full-thickness fragment of soft tissue at the hard palate area, between the upper bicuspids, 3 to 4 mm apical to the cement enamel junction. The one-third inner portion was fragmented, and following standard cell culture procedures, the adherent cells were cultured for three passages, after obtaining 70–90% confluence. Cell morphology analysis, flow cytometry analysis, and viability and osteogenic differentiation assays were performed. In all 10 cases, uneventful healing was observed, with no need for analgesic intake. The evaluation of cell morphology showed elongated spindle-shaped cells distributed in woven patterns. A high viability range was verified as well as an immunophenotype compatible with mesenchymal stem cell lineage. The differentiation assay showed the potential of the cells to differentiate into the osteogenic lineage. These results demonstrate that the minimally invasive proposed surgical technique is capable of supplying enough periosteum source tissue for stem cell culture and bone tissue engineering.

The aim of this study was to test whether lyophilized conditioned media from human dental pulp mesenchymal stem cell cultures promote the healing of critical-size defects created in the calvaria of rats. Prior to the surgical procedure, the medium in which dental pulp stem cells were cultured was frozen and lyophilized. After general anesthesia, an 8 mm diameter bone defect was created in the calvaria of twenty-four rats. The defects were filled with the following materials: xenograft alone (G1) or xenograft associated with lyophilized conditioned medium (G2). After 14 or 42 days, the animals were euthanized, and the specimens processed for histologic and immunohistochemical analysis. Bone formation at the center of the defect was observed only in the G2 at 42 days. At both timepoints, increased staining for VEGF, a marker for angiogenesis, was observed in G2. Consistent with this, at 14 days, G2 also had a higher number of blood vessels detected by immunostaining with an anti-CD34 antibody. In conclusion, conditioned media from human dental pulp mesenchymal stem cell cultures had a positive effect on the regenerative process in rat critical-size bone defects. Both the formation of bone and enhancement of vascularization were stimulated by the conditioned media.

Natural polymers are increasingly being used in tissue engineering due to their ability to mimic the extracellular matrix and to act as a scaffold for cell growth, as well as their possible combination with other osteogenic factors, such as mesenchymal stem cells (MSCs) derived from dental pulp, in an attempt to enhance bone regeneration during the healing of a bone defect. Therefore, the aim of this study was to analyze the repair of mandibular defects filled with a new collagen/chitosan scaffold, seeded or not with MSCs derived from dental pulp. Twenty-eight rats were submitted to surgery for creation of a defect in the right mandibular ramus and divided into the following groups: G1 (control group; mandibular defect with clot); G2 (defect filled with dental pulp mesenchymal stem cells—DPSCs); G3 (defect filled with collagen/chitosan scaffold); and G4 (collagen/chitosan scaffold seeded with DPSCs). The analysis of the scaffold microstructure showed a homogenous material with an adequate percentage of porosity. Macroscopic and radiological examination of the defect area after 6 weeks post-surgery revealed the absence of complete repair, as well as absence of signs of infection, which could indicate rejection of the implants. Histomorphometric analysis of the mandibular defect area showed that bone formation occurred in a centripetal fashion, starting from the borders and progressing towards the center of the defect in all groups. Lower bone formation was observed in G1 when compared to the other groups and G2 exhibited greater osteoregenerative capacity, followed by G4 and G3. In conclusion, the scaffold used showed osteoconductivity, no foreign body reaction, malleability and ease of manipulation, but did not obtain promising results for association with DPSCs.

In this work, a simple method was proposed to produce dense composite polysaccharide-based membranes to be used for guided tissue and guided bone regeneration. The mucoadhesive polysaccharides chitosan (C) and xanthan gum (X) were used to produce polyelectrolyte-based complex membranes. Hydroxyapatite (HA) was added to the formulation as a potential drug carrier, in C:X:HA mass proportions equal to 1:1:0.4, 1:1:2, and 1:1:10, and also to improve membranes bioactivity and biomimetic properties. FTIR analysis indicated successful incorporation of HA in the membranes and XRD analysis showed that no changes in the HA crystalline structure were observed after incorporation. The residual mass evaluated by TGA was higher for the formulation produced at the proportion 1:1:10. The membranes produced showed asymmetrical surfaces, with distinct roughness. Increasing the HA concentration increased the surface roughness. Greater in vitro proliferation of dental pulp mesenchymal stem cells was observed on the surface of the membrane with 1:1:10 C:X:HA proportion. However, the 1:1:2 formulation showed the most adequate balance of mechanical and biological properties. These results suggest that adding HA to the membranes can influence mechanical parameters as well as cell adhesion and proliferation, supporting the potential application of these materials in regenerative techniques and the treatment of periodontal lesions.

In the present study, hydroxyapatite and Zn-substituted hydroxyapatite powders were synthesized using ostrich eggshell as a calcium source. The samples were analyzed by scanning electron microscopy with field emission gun, and X-ray diffraction (XRD) to identify the present phases, and X-ray fluorescence spectroscopy for quantitative chemical analysis of the synthesized and heat treated powders. The Fourier transform infrared spectroscopy technique was used before and after heat treatments at 700, 900 and 1100 °C in order to identify the functional groups present, as an additional technique to the XRD analysis. The results presented in this study represent a promising method for synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc, since the results showed no undesirable phases or impurities in the produced powders. It was observed that Zn-substituted hydroxyapatite showed higher thermal stability, when compared to pure hydroxyapatite.