Eduardo Rolim Teixeira

Background: Extracellular vesicle (EV)-associated microRNAs (miRNAs) have been implicated in intercellular signaling processes relevant to bone regeneration; however, the regulatory relationships through which selected EV-associated miRNAs may converge on biological processes relevant to bone repair remain incompletely understood. Objective: To investigate, using an in silico systems biology approach, the predicted regulatory architecture of five literature-selected EV-associated miRNAs potentially involved in biological processes relevant to bone regeneration. Methods: Five miRNAs (hsa-miR-146a-5p, hsa-miR-21-5p, hsa-miR-335-5p, hsa-miR-503-5p, and hsa-miR-129-5p) were selected a priori based on published evidence linking them to EV-associated signaling and/or osteogenesis-related biological processes. Candidate target genes were predicted using TargetScan Human 8.0 and prioritized according to Context++ score ranking, followed by predicted target-overlap analysis, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment pathway enrichment, and miRNA–messenger RNA (mRNA) network reconstruction using Cytoscape 3v.10. Results: The five miRNAs yielded 395 prioritized predicted miRNA–mRNA interactions corresponding to 387 unique predicted target genes, with most predicted targets associated with a single miRNA and a limited subset shared between pairs of miRNAs. Eight genes were identified as pairwise shared predicted targets, with no higher-order overlap involving three or more miRNAs. SMAD family member 7 (SMAD7) was identified as was identified as a pairwise shared predicted target of hsa-miR-21-5p and hsa-miR-503-5p and was selected for biological contextualization because of its involvement in transforming growth factor beta (TGF-β)/bone morphogenetic protein (BMP)-associated signaling. Functional enrichment identified statistical overrepresentation of signaling pathways regulating pluripotency of stem cells, as well as mitogen-activated protein kinase (MAPK), Hippo, TGF-β, Wnt, mechanistic target of rapamycin (mTOR), and forkhead box O (FoxO) signaling pathways. Conclusions: This exclusively computational analysis identified a predicted regulatory architecture characterized by predominantly miRNA-specific target relationships, limited pairwise target overlap, and pathway-level enrichment potentially relevant to bone-related biological processes. These findings are hypothesis-generating and do not establish miRNA abundance within a specific EV preparation, direct miRNA–mRNA regulation, pathway activation, or osteoregenerative activity. Experimental EV cargo characterization and functional validation in relevant cellular and in vivo models are required to determine the biological significance of the predicted relationships.

Background: Bone regeneration requires coordinated regulation of osteogenesis angiogenesis, extracellular matrix remodeling, immune responses, and mineralization. Extracellular vesicle (EV)-based therapies have emerged as promising cell free strategies, although their molecular mechanisms remain incompletely understood. Objective: To investigate the molecular mechanisms potentially underlying the osteoregenerative effects of an EV concentrate using an in silico systems biology approach. Methods: Five osteogenesis and immunomodulation related microRNAs (hsa-miR-146a-5p, hsa-miR-21-5p, hsa-miR-335-5p, hsa-miR-503-5p, and hsa-miR-129-5p) were analyzed. High-confidence target genes were identified using TargetScan 8.0, followed by overlap analysis, Gene Ontology and KEGG enrichment, and miRNA-mRNA network reconstruction in Cytoscape. Results The selected miRNAS regulated hundreds of predicted targets, displaying complementary rather than universal target overlap. SMAD7 emerged as a key shared regulatory node involved in TGF-β/BMP signaling. Functional enrichment demonstrated significant associations with osteoblast differentiation, angiogenesis, extracellular matrix organization, inflammatory regulation, and mineralization. Pathway analysis identified convergence on MAPK, Wnt/β-catenin, TGF-β/BMP, PI3K/Akt, FoxO, Hippo, AMPK, and NF-κB signaling. Conclusions: These findings indicate that EV concentrates may promote bone regeneration through coordinated miRNA-mediated regulation of multiple osteoregenerative pathways, providing a mechanistic framework for developing cell-free regenerative therapies and guiding future experimental validation.

Segalla DB, et al. J Adv Prosthodont. 2025 Oct;17(5):259-268. https://doi.org/10.4047/jap.2025.17.5.259

Objectives: This experimental laboratory study aimed to compare the effect of four external irrigation protocols on bone tissue heating during guided implant drilling. Methods: Forty perforations were made in ten bovine rib specimens using customized surgical templates. Four experimental groups (n=10/group) were tested: Control group = 10-ml syringe with 25°C saline solution, Group 1 = 10-ml syringe with 10°C saline solution, Group 2 = combined external irrigation using a handpiece and a 10-ml syringe with 25°C saline solution, and Group 3 = combined external irrigation using a handpiece and a 10-ml syringe with 10°C saline solution. The temperature was measured at cervical and apical points using K-type thermocouples, a digital thermometer, and a video recorder. Data were analyzed by ANOVA and Pearson’s correlation coefficients (alpha=0.05). Results: The maximum temperature was 42°C (cervical) and 44°C (apical). No difference in temperature changes was found among groups, but the difference between bone specimens was statistically significant. Temperature and time were positively associated for most groups, mainly in the cervical region. Conclusions: All irrigation methods were equally effective in controlling the bone temperature in cervical and apical regions. However, longer drilling times caused a greater increase in temperature.

Purpose It is known that a correct transverse maxillary dimension is a key factor for a stable occlusion, which brings functional and esthetic benefits for the patient. In patients presenting maxillary atresia and the completion of bone growth, a highly recommended option for correction is the surgically assisted rapid maxillary expansion (SARME) associated with the Hyrax appliance. The objective of this study was to evaluate the influence of tooth anchorage variations of the Hyrax appliance in SARME through finite element analysis, evaluating which anchorage option might be associated with more effective orthopedic results with less undesired side effects. Methods Five different dental anchoring conditions for the Hyrax appliance were simulated through FE analysis applying premolars and molars as anchorage, having the same force applied by the activation of the Hyrax screw (0.5 mm) in all groups. The maxillary displacement results (axes X, Y, and Z) and generated stresses for both teeth and maxillary bone were calculated and represented using a color scale. Results All groups presented significant bone displacement and stress concentration on anchoring teeth, with the group presenting anchorage in the 1st and 2nd molars showing the greatest maxillary horizontal displacement (axis X) and suggesting the lowest tendency of dental vestibular inclination. Conclusions Variations in dental anchorage might substantially affect the maxillary bone and teeth displacement outcome. The protocol for the Hyrax apparatus in SARME applying the 1st and 2nd molars as anchorage might generate less tilting and inclination of the anchoring teeth.

Hydrophilic and nanotextured surfaces for dental implants have been reported as relevant properties for early osseointegration. However, these surface characteristics are quite sensitive to oral interactions. Therefore, this pilot study aimed to investigate the superficial alterations caused on hydrophilic nanotubular surfaces after early human saliva interaction. Titanium disks were treated using an anodization protocol followed by reactive plasma application in order to achieve nanotopography and hydrophilicity, additionally; surfaces were stored in normal atmospheric oxygen or wet conditioning. Following, samples were interacted with saliva for 10 min and analyzed regarding physical–chemical properties and cellular viability. Saliva interaction did not show any significant influence on morphological characteristics, roughness measurements and chemical composition; however, hydrophilicity was statistically altered compromising this feature when the samples were stored in common air. Cellular viability tested with pre-osteoblasts cell line (MC3T3-E1) reduced significantly at 48 h on the samples without wet storage after saliva contamination. The applied wet-storage methodology appears to be effective in maintaining properties such as hydrophilicity during saliva interaction. In conclusion, saliva contamination might impair important properties of hydrophilic nanotubular surfaces when not stored in wet conditions, suggesting the need of saliva-controlled sites for oral application of hydrophilic surfaces and/or the use of modified-package methods associated with their wet storage.

Objectives This study evaluated hyaluronic acids (HA) with different molecular weights as potential matrices for tissue-engineered bone grafting and their possible influence on the paracrine mechanisms of adipose-derived mesenchymal stromal cells. Material and methods Murine adipose mesenchymal stromal cells (mASCs) on the fourth passage were seeded in 96-well plates, osteoinduced for 27 days and exposed for 3 days to low (HA-LW) and high/low molecular weight (HA-HLW) at previously defined concentrations. Cytokines IGF-1, VEGF, FGF-2, and BMP-2 were evaluated by quantification in the supernatant. Results Greater expression of growth factors was observed in groups with HA-HLW compared to HA-LW. Results indicated that differentiated cells secreted fewer cytokines, namely VEGF, FGF, and BMP-2 than undifferentiated mASCs (p < 0.05). IGF-1 showed its greatest expression in the mASC HA-LW group (p < 0.05). Conclusions The application of HA-HLW as cell matrix in tissue engineering did not compromise mASC paracrine effect. Also, the association of HA-HLW matrix and mASCs resulted in greater expression of osteogenic growth factors. Longer periods of cell differentiation seemed to negatively affect their capacity for local paracrine stimulation. Clinical relevance The use of HA-HLW as matrix for undifferentiated ASCs can be positive for bone regeneration, favoring its application as cell matrix in bone grafting procedures.

This study investigates the applicability of adipose mesenchymal stem cells (mADSCs) and hyaluronic acid (HA) as a cellular compound for bone tissue engineering. A critical bone defect was created on each femur of 25 rats in vivo, receiving the following 5 graft treatments: I—Control-defect; II—HA; III—mADSCs; IV—mADSCs+HA; and V—previously osteoinduced mADSCs+HA. Evaluation using microcomputed tomography, histomorphometry, and RT-PCR analysis was performed 23 days after implantation. Microcomputed tomography analysis indicated higher means of bone contact surface (BCS) and bone surface density (BSD) for the mADSCs+HA group compared with Control and the HA groups (P < 0.05). Histomorphometric findings showed higher means of bone regeneration in the mADSCs+HA compared with HA and Control groups (P < 0.05). The RT-PCR ratios showed no difference in type 1 collagen (Col1A) gene expression or osteopontin (OP) gene expression, whereas for the osteonectin gene (ON) higher means were found in the HA and mADSCs osteoin+HA groups (P < 0.05). These results suggest that a combination of HA and mADSCs without prior osteoinduction might be applicable for bone tissue regeneration.