Recovering the osteoblastic differentiation potential of mesenchymal stem cells derived from diabetic rats by photobiomodulation therapy

Autologous cell-based therapy for bone regeneration might be impaired by diabetes mellitus (DM) due to the negative effects on mesenchymal stem cells (MSCs) differentiation. Strategies to recover their osteogenic potential could optimize the results. We aimed to evaluate the effect of photobiomodulation (PBM) therapy on osteoblast differentiation of rats with induced DM. Bone marrow MSCs of healthy and diabetic rats were isolated and differentiated into osteoblasts (OB and dOB, respectively). dOB were treated with PBM therapy every 72 hour (660 nm; 0.14 J; 20 mW; 0.714 W/cm² , and 5 J/cm² ). Cell morphology, viability, gene and protein expression of osteoblastic markers, alkaline phosphatase (ALP) activity, and the mineralized matrix production of dOB-PBM were compared to dOB. PBM therapy improved viability of dOB, increased the gene and protein expression of bone markers, the ALP activity and the mineralized matrix production. PBM therapy represents an innovative therapeutic approach to optimize the treatment of bone defects in diabetic patients.

Exposure to lipopolysaccharide and calcium silicate-based materials affects the behavior of dental pulp cells

This study assessed the cell viability, cytokine production, and mineralization potential of human dental pulp cells (hDPCs) after exposure to lipopolysaccharide (LPS) and application of calcium silicate-based materials (CSBM). Characterization of the CSBM was performed by infrared spectroscopy (n = 3). Extracts of Bio-C Repair, Biodentine, Cimmo HD, and MTA Repair HP were prepared and diluted (1:1, 1:4, and 1:16). Culture of hDPCs was established and treated or not with 1 µg/mL of LPS from Escherichia coli for 7 days. MTT assay was used to assess cell viability at 24, 48, and 72 h (n = 6). Alkaline phosphatase (ALP) activity was assayed on day 7 (n = 4). Il-10 and TNF-α were quantified by ELISA at 24 h (n = 6). Data were analyzed by ANOVA and Tukey's test (α = 0.05). Cell viability of LPS-activated hPDCs was higher than untreated control in 48 and 72 h (p < 0.05). Differences between non-treated and LPS-activated hPDCs were observed for Biodentine and Cimmo HP (p < 0.05). The CSBM influenced the cell viability (p < 0.05). ALP activity was higher in LPS-activated hDPCs (p < 0.05). No changes in the concentration of TNF-α were observed between groups (p > 0.05). The CSBM increased the Il-10 production (p < 0.05). LPS-activated hDPCs presented increased cell viability and ALP activity. The CSBM showed mild toxicity and was able to enhance the cell viability and mineralization potential of untreated and LPS-activated hDPCs. The CSBM also induced anti-inflammatory mechanisms without compromising pro-inflammatory ones.

Bioactive glass-ceramic for bone tissue engineering: an in vitro and in vivo study focusing on osteoclasts

Despite the crucial role of osteoclasts in the physiological process of bone repair, most bone tissue engineering strategies have focused on osteoblast-biomaterial interactions. Although Biosilicate® with two crystalline phases (BioS-2P) exhibits osteogenic properties and significant bone formation, its effects on osteoclasts are unknown. This study aimed to investigate the in vitro and in vivo effects of BioS-2P on osteoclast differentiation and activity. RAW 264.7 cells were cultured in osteoclastogenic medium (OCM) or OCM conditioned with BioS-2P (OCM-BioS-2P), and the cell morphology, viability, and osteoclast differentiation were evaluated. BioS-2P scaffolds were implanted into rat calvarial defects, and the bone tissue was evaluated using tartrate-resistant acid phosphatase (TRAP) staining and RT-polymerase chain reaction (PCR) after 2 and 4 weeks to determine the gene expressions of osteoclast markers and compare them with those of the bone grown in empty defects (Control). OCM-BioS-2P favored osteoclast viability and activity, as evidenced by an increase in the TRAP-positive cells and matrix resorption. The bone tissue grown on BioS-2P scaffolds exhibited higher expression of the osteoclast marker genes (Ctsk, Mmp 9, Rank) after 2 and 4 weeks and the RankL/Opg ratio after 2 weeks. Trap gene expression was lower at 2 weeks, and a higher number of TRAP-stained areas were observed in the newly formed bone on BioS-2P scaffolds at both 2 and 4 weeks compared to the Controls. These results enhanced our understanding of the role of bioactive glass-ceramics in bone repair, and highlighted their role in the modulation of osteoclastic activities and promotion of interactions between bone tissues and biomaterials.

Unusual giant complex odontoma: A case report

Odontomas are benign, non-aggressive, and the most common odontogenic tumor of the jaws. Composed of dental tissues, it can be classified as compound or complex odontomas depending on their radiological and histological features. Among them, complex odontomas are less common and usually is presented as a small and asymptomatic radiopaque mass surrounded by a radiolucent halo, found on routine radiographic examination. Although benign tumors, odontomas can reach large sizes leading to facial asymmetry and decreasing bone strength, which predisposes fractures and infection. Our aim was to present a case report of an unusual giant mandibular odontoma on the left mandibular angle and ramus successfully treated by surgical excision and highlight the importance of the earlier diagnostic to minimize damages.

Photobiomodulation using 940-nm laser as an adjuvant therapy on orthognathic surgery: A randomized clinical trial

This study aimed to evaluate the effectiveness of photobiomodulation (PBM) therapy using 940-nm laser in patients undergoing orthognathic surgery. Twenty individuals were randomly distributed into laser (n = 10) and control (n = 10) groups. The PBM was conducted immediately after surgery, after 24 h, 48 h, and weekly for up to 4 weeks. All participants were evaluated for pain, edema, trismus and paresthesia. Data were compared by Fisher's and Mann-Whitney or chi-square tests (5%). The pain decreased from 24 h to 4 weeks, with the laser group reaching any pain after 3 weeks (p < 0.001). A significant difference was noticed for trismus on days 14 and 30 (p = 0.002; p = 0.019), without difference in paresthesia (p = 0.198). Edema was lower on the laser group compared to control, without a significant difference for most measurements. Data indicate that 940-nm PBM therapy decreased the occurrence of postoperative pain and significantly improved trismus.

Response of periodontal ligament stem cells to lipopolysaccharide and calcium silicate-based materials

This study was conducted to assess the in vitro response of human periodontal ligament stem cells (hPDLSCs) to bacterial lipopolysaccharide (LPS) activation and application of three calcium silicate-based materials (CSBM): Bio-C Sealer, MTA Fillapex and Cimmo HP. Characterization of the CSBM was performed by FTIR (n = 3). Extracts of Bio-C Sealer, MTA Fillapex and Cimmo HP were prepared and diluted (1:1, 1:4 and 1:16). Culture of hPDLSCs was established and treated or not with LPS from Escherichia coli (1 µg/mL) for 7 days. MTT assay was used to assess cell viability at 24, 48 and 72 h (n = 9). Alkaline phosphatase (ALP) activity was indirectly assayed at day 7 (n = 5). TNF-α and Il -1 0 cytokines were quantified by ELISA at 24h-cell supernatants (n = 6). Data were analyzed by ANOVA and Tukey's test (α = 0.05). The cell viability of the LPS-activated hPDLSCs were higher than untreated control (p < 0.05). The application of CSBM affected the cell viability of untreated and LPS-activated cells (p < 0.05). ALP activity was higher for Bio-C Sealer and Cimmo HP in untreated and LPS-activated cells, respectively (p < 0.05). Application of CSBM normalized the TNF-α secretion in the LPS-activated cells (p < 0.05). Only MTA Fillapex in untreated hPDLSCs presented higher values of Il -1 0 (p < 0.05). Taken collectively, the results suggests that the simulation of the inflammatory process by LPS affect the in vitro response the hPDLSCs to the application of the CSBM.

Enhancing osteoblast differentiation and bone repair: The priming effect of photobiomodulation on adipose stromal cells

Cellular therapy using adipose tissue-derived mesenchymal stromal cells (at-MSCs) has garnered attention for the treatment of bone defects. Therefore, preconditioning strategies to enhance the osteogenic potential of at-MSCs could optimize cell therapy outcomes, and photobiomodulation (PBM) therapy has emerged as an effective, noninvasive, and low-cost alternative. This study explored the impacts of PBM on at-MSCs differentiation and the subsequent repair of bone defects treated with cell injection. Rat at-MSCs were cultured and irradiated (at-MSCsPBM) following the PBM protocol (660 nm; 20 mW; 0.714 W/cm2; 0.14 J; 5 J/cm2). Cellular differentiation was assessed based on the expression of gene and protein markers. Reactive oxygen species (ROS) were detected using fluorescence. At-MSCsPBM were injected into 5-mm calvarial lesions, and bone formation was analyzed using micro-CT and histological evaluations. At-MSCs were used as control. Data were analyzed using the ANOVA or t-test. At-MSCsPBM exhibited high levels of gene and protein runt-related transcription factor-2 (Runx2) and alkaline phosphatase (Alp) expression. PBM increased ALP activity and significantly reduced ROS levels. In addition, PBM increased the expression of Wnt pathway-associated genes. In vivo, there was an increase in the morphometric parameters, including bone volume, percentage of bone volume, bone surface area, and trabecular number, in at-MSCsPBM-treated defects compared with those in the control. These findings suggest that PBM enhances the osteogenic potential of at-MSCs, thereby supporting the advancement of improved cellular therapies for bone regeneration.

[Stress test in the elderly. Clinical, hemodynamic, metabolic and electrocardiographic variables]

PURPOSE

To identify in the elderly adaptations imposed by exercise in both sexes.

METHODS

1528 stress tests were performed on subjects divided in: group I (GI) (90%) between 65 to 75 years old, and group II (GII) more than 75 years old. Protocols applied were Bruce (72%), and modified Naughton (28%). Clinical, hemodynamic and electrocardiographic variables were estimated as recommended by the World Health Organization, and the metabolic variables in the adapted Naughton protocols by the American College of Sports Medicine standards.

RESULTS

Analysis of GI and GII, respectively disclosed: 1) stress electrocardiogram (ECG): normal, 36 and 35%; ST depression, 20 and 22%; ST elevation, 6 and 1%; ventricular ectopic beats, 11 and 14%; supra ventricular ectopic beats, 5 and 6%; 2) metabolic and hemodynamic variables: the double-product: 26636 (+/-1539) and 23133 (+/-3218) mmHg X bpm (p < 0.0001). Maximum oxygen uptake measured in METS: GI, men, 7.7 (+/-1.9), women 5.4 (+/-0.8) (p < 0.0001); GII, NS, curve of systolic blood pressure: GI, men, 8.4 +/- (0.5), women, 10.6 (+/-1.8) mmHg/Met (p = 0.03); GII- NS. Difference of diastolic blood pressure and heart rate during exercise were similar between the two groups; 3) chest pain was the main clinical variable.

CONCLUSION

The more frequent indication for stress testing to evaluate chest pain in GI, did not correspond to a predominance of this symptom in this group, during exercise; in GI, in contrast to what is seen in the young, the curve of systolic blood pressure was greater in women; despite the greater prevalence of coronary artery disease in aged subjects, it was not observed significative differences between the two groups, to ischaemic ST depression.