Osteoblastic differentiation and changes in the redox state in pulp stem cells by laser treatment.

The aim of this study was to determine the effect of low-level laser therapy (LLLT) on cell proliferation, mitochondrial membrane potential changes (∆Ψm), reactive oxygen species (ROS), and osteoblast differentiation of human dental pulp stem cells (hDPSCs). These cells were irradiated with 660- and 940-nm lasers for 5 s, 50 s, and 180 s. Cell proliferation was assessed using the resazurin assay, cell differentiation by RUNX2 and BMP2 expression, and the presence of calcification nodules using alizarin-red S staining. ROS was determined by the dichlorofluorescein-diacetate technique and changes in ∆Ψm by the tetramethylrhodamine-ester assay. Data were analyzed by a Student's t-test and Mann-Whitney U test. The 940-nm wavelength for 5 and 50 s increased proliferation at 4 days postirradiation. After 8 days, a significant decrease in proliferation was observed in all groups. Calcification nodules were evident in all groups, with a greater staining intensity in cells treated with a 940-nm laser for 50 s, an effect that correlated with increased RUNX2 and BMP2 expression. ROS production and Δψm increased independently of irradiation time. In conclusion, photobiomodulation (PBM) with LLLT induced morphological changes and reduced cell proliferation rate, which was associated with osteoblastic differentiation and increased ROS and Δψm, independent of wavelength and time.

Relaxin treatment stimulates the differentiation of mesenchymal stem cells into osteoblasts.

Background/purpose: Several studies have determined that relaxin stimulates differentiation and regulates the activity of mature osteoclasts, but little is known about its effect on the differentiation of mesenchymal cells towards the osteogenic lineage. Therefore, this study aimed to determine the effect of relaxin on the proliferation and differentiation of the osteoblastic lineage of mesenchymal cells derived from human dental pulp (hDPSC). Materials and methods: In this in vitro study, hDPSC were characterized and treated with relaxin at different doses (10-80 ng/ml) and times (1-21 days). Morphology was assessed by microscopy, and proliferation was assessed using a resazurin assay. Osteoblastic differentiation was evaluated by Alizarin Red staining, alkaline phosphatase (ALP) labeling, and changes in the expression of the osteoblastic differentiation genes RUNX2 and BMP2. Results: Relaxin treatment did not induce changes in the proliferation or viability of hDPSCs; however, larger cells and increased cytoplasmic prolongation were observed. Relaxin treatment (20 and 80 ng/ml) significantly increased calcified nodule formation on days 14 and 21. The cytochemical signals for ALP, RUNX2, and BMP2 gene expression were significantly (P < 0.05) increased by the relaxin treatment. Conclusion: Relaxin treatment does not induce changes in hDPSC proliferation but induces morphological changes, increases ALP detection, calcified nodule formation, and increases expression of RUNX2 and BMP2, suggesting the induction of osteoblastic differentiation of hDPSC.

Parents' Perception of Barriers to the Comprehensive Management of Children With Cleft Lip and Palate in Bogota, Colombia.

OBJECT: To identify the perception of barriers to the comprehensive management of cleft lip and palate (CLP) by parents/caregivers of Colombian children with this condition. SETTING AND SAMPLE POPULATION: Fifty parents/caregivers of children with CLP under 12 years attending a center specialized in the management of craniofacial congenital conditions in Bogota, Colombia. MATERIALS AND METHODS: This study consisted of 2 phases: a quantitative phase (descriptive cross-sectional) and a qualitative phase (focus group [FG]). Chi-square and Fisher exact tests were used to analyze the association variables. The barriers and alternative ways to overcome barriers were analyzed in the FG. RESULTS: Comprehensive management was mostly defined as access to multiple treatments (54%), and this concept was expanded in the FG toward understanding CLP at all levels. Monoparental families spend their income on treatments (29%) than nuclear families (0%) (P = .001). All parents with high education levels were familiar with healthcare centers specialized in CLP as opposed to 66.7% of parents with basic primary education (P < .05). Regarding the timeliness of appointments, 12.2% of parents earning between 1 and 2 minimum wages reported some kind of difficulty, whereas those earning less than one minimum wage reported difficulties in 66.7% of cases (P = .046). CONCLUSIONS: All participants reported barriers, which increased or decreased depending on their socioeconomic status. The FG allowed the discussion of alternatives to overcome barriers, such as structural, solidarity, and self-management actions.

Retinoic and ascorbic acids induce osteoblast differentiation from human dental pulp mesenchymal stem cells.

Previous studies have suggested an important role of retinoic acid (RA) and ascorbic acid (AA) in the stimulation of osteoblastic differentiation; however, the function of RA and AA in the osteogenic differentiation from human dental pulp (hDPSCs) remains unclear. OBJECTIVE: This in vitro study investigated the effects of RA and AA on the differentiation of osteoblast from hDPSCs. METHODS: hDPSCs were treated with different doses of RA and AA, separately or in combination (RA â€‹+ â€‹AA). Morphology and cell proliferation were assessed. Osteoblast differentiation was evaluated by alizarin red, alkaline phosphatase staining, and RUNX2 gene expression. RESULTS: A significant reduction was observed in the number of cells treated with RA (26%) and RA â€‹+ â€‹AA (30%) after 12 days of treatment. AA treatment alone induced a 12% reduction in the number of cells. Morphologically, the cells treated with RA and RA â€‹+ â€‹AA were larger and more elongated than the control cells. A mesh pattern was observed in cells treated with AA. Numerous calcified nodules were present in cells treated with RA, AA, and RA â€‹+ â€‹AA. This coincided with increased expression of RUNX2 and high alkaline phosphatase staining levels. CONCLUSIONS: hDPSCs treated with RA and RA â€‹+ â€‹AA showed significant reduction in proliferation, detectable morphological changes, and expression of the key differentiation gene RUNX2, consistent with an osteoblast phenotype. AA induced morphological changes and early formation of calcified nodules. RA had a predominant effect when AA and RA were used together.

Effect of Vitamins D and E on the Proliferation, Viability, and Differentiation of Human Dental Pulp Stem Cells: An In Vitro Study.

INTRODUCTION: The aim of the present study was to determine the effects of vitamins D and E on the proliferation, morphology, and differentiation of human dental pulp stem cells (hDPSCs). METHODS: In this in vitro experimental study, hDPSCs were isolated, characterized, and treated with vitamins D and E, individually and in combination, utilizing different doses and treatment periods. Changes in morphology and cell proliferation were evaluated using light microscopy and the resazurin assay, respectively. Osteoblast differentiation was evaluated with alizarin red S staining and expression of RUNX2, Osterix, and Osteocalcin genes using real-time RT-PCR. RESULTS: Compared with untreated cells, the number of cells significantly reduced following treatment with vitamin D (49%), vitamin E (35%), and vitamins D + E (61%) after 144 h. Compared with cell cultures treated with individual vitamins, cells treated with vitamins D + E demonstrated decreased cell confluence, with more extensive and flatter cytoplasm that initiated the formation of a significantly large number of calcified nodules after 7 days of treatment. After 14 days, treatment with vitamins D, E, and D + E increased the transcription of RUNX2, Osterix, and Osteocalcin genes. CONCLUSIONS: Vitamins D and E induced osteoblastic differentiation of hDPSCs, as evidenced by the decrease in cell proliferation, morphological changes, and the formation of calcified nodules, increasing the expression of differentiation genes. Concurrent treatment with vitamins D + E induces a synergistic effect in differentiation toward an osteoblastic lineage.