Publications by authors named "Karina Fittipaldi Bombonato-Prado"

20 Publications

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Preadministration of yerba mate (Ilex paraguariensis) helps functional activity and morphology maintenance of MC3T3-E1 osteoblastic cells after in vitro exposition to hydrogen peroxide.

Mol Biol Rep 2021 Jan 17;48(1):13-20. Epub 2021 Jan 17.

Department of Basic and Oral Biology, Bone Research Lab, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.

Natural substances with antioxidant effects may benefit prevention and treatment of people with or prone to bone diseases after menopause, such as osteoporosis. This study aimed to evaluate the in vitro effect of preadministration of yerba mate extract (YM) in the metabolism of MC3T3-E1 osteoblasts exposed to hydrogen peroxide (HO). The cells (MC3T3-E1) were cultured in 24-well plates with the concentration of 1 μg/mL yerba mate extract dissolved in culture medium throughout the culture period. Four hours before each experiment, 400 μmol/L HO was added per well to simulate oxidative stress. There were evaluated cell adhesion and proliferation, in situ detection of alkaline phosphatase (ALP), mineralized nodules, and immunolocalization of osteocalcin (OCN), bone sialoprotein (BSP) and alkaline phosphatase (ALP) proteins. The results showed that YM preadministration to HO exposition significatively increased cell adhesion after 3 days as well as proliferation and in situ ALP detection after 10 and 7 days respectively, when compared to HO group. Besides, staining of OCN and BSP proteins was less intense and scattered in poor spread cells with cytoskeletal changes in HO group when compared to control and YM HO group. ALP staining was restrained to intracellular regions and similar in all experimental groups. Our results suggest that preadministration of yerba mate extract may prevent deleterious effects in the morphology and functional activity of osteoblasts exposed to HO, which could enable the maintenance of extracellular matrix in the presence of oxidative stress.
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http://dx.doi.org/10.1007/s11033-020-06096-wDOI Listing
January 2021

Osteoporosis Affects Functional Activity and Gene Expression of Osteoblastic Cells Derived from Rat Alveolar Bone.

Braz Dent J 2020 Nov-Dec;31(6):617-622

Bone Research Lab, Department of Basic and Oral Biology, School of Dentistry, USP - Universidade de São Paulo, Ribeirão Preto, SP, Brazil.

Recent studies suggest that osteoporosis, in addition to the damage caused in long bones, may cause deterioration in the jaws, especially in alveolar bone sites, with effects in the progress of periodontal disease as well as in bone healing. The aim of this study was to evaluate the effect of osteoporosis in the metabolism of rat alveolar bone osteoblasts. There were used 10 female rats divided in two experimental groups (Sham and OVX), which were ovariectomized and after 8 weeks euthanized to collect mandibular bone samples in order to isolate osteoblastic cells. The cells were cultured in 24-well plates to perform the in vitro experiments. After 7, 10 and 14 days, there were evaluated cell proliferation by MTT assay, in situ detection of alkaline phosphatase (ALP) as well as mineralized nodules and expression of genes associated to bone remodeling. Results showed that at 7, 10 and 14 days cell proliferation was lower for OVX group. In situ detection of ALP was higher at 7 days and lower at 10 and 14 days in OVX group. At 17 and 21 days, OVX group had a significative decrease of mineralization nodules. There was a downregulation in the expression of Alp, Bglap and Runx2 genes and an upregulation of Opg in OVX group, whereas Opn and Rankl modulation was similar between the evaluated groups. Our results suggest that osteoporosis has a deleterious effect on alveolar bone cells from ovariectomized rats, which might affect the treatment of diseases associated to the jaw bones.
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http://dx.doi.org/10.1590/0103-6440202003068DOI Listing
November 2020

Green tea extract rich in epigallocatechin gallate impairs alveolar bone loss in ovariectomized rats with experimental periodontal disease.

Int J Exp Pathol 2020 12 11;101(6):277-288. Epub 2020 Nov 11.

Bone Research Lab, Department of Basic and Oral Biology, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.

Periodontal disease and osteoporosis are characterized by bone resorption, and researchers have shown an association between these two diseases through increasing loss of systemic bone mass and triggering alveolar bone loss. Green tea is a common and easily accessible beverage, and evidences show that flavonoid epigallocatechin gallate (EGCG) could decrease bone loss in pathologies such as osteoporosis and periodontal disease. In order to verify its possible effects and apply them in the treatment and prevention of these diseases, this investigation aimed to evaluate the influence of green tea extract (GTE) on bone metabolism of ovariectomized rats after experimental periodontal disease (EPD) by histological, morphological and microtomographic parameters. Wistar female rats were divided into Sham, Sham + EPD, Sham + EPD + GTE, OVX, OVX + EPD and OVX + EPD + GTE groups. Immediately after surgery, gavage administration of 50 mg/kg of green tea extract (GTE) was performed for 60 days, with subsequent induction of periodontal disease by ligature 15 days before euthanasia. Mandible and femur samples were collected for histological, morphometric and microtomographic analysis. The results were analysed by means of statistical software with significance set at 5%. Histological and morphometric analysis showed a significant decrease in alveolar and femoral trabecular bone loss in groups that received GTE. Microtomographic results showed that trabecular thickness and bone surface density values in alveolar bone interradicular septum of the OVX + EPD + GTE groups were similar to the Sham group. The results obtained suggest that green tea extract may improve bone metabolism in osteoporotic rats with periodontal disease.
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http://dx.doi.org/10.1111/iep.12379DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7691221PMC
December 2020

Impact of calcium aluminate cement with additives on dental pulp-derived cells.

J Appl Oral Sci 2020 28;28:e20190105. Epub 2019 Nov 28.

Universidade de Ribeirão Preto, Faculdade de Odontologia, Ribeirão Preto, SP, Brasil.

Calcium aluminate cement (CAC) has been highlighted as a promising alternative for endodontic use aiming at periapical tissue repair. However, its effects on dental pulp cells have been poorly explored.

Objective: This study assessed the impact of calcium chloride (CaCl2) and bismuth oxide (Bi2O3) or zinc oxide (ZnO) additives on odontoblast cell response to CAC.

Methodology: MDPC-23 cells were exposed for up to 14 d: 1) CAC with 2.8% CaCl2 and 25% ZnO (CACz); 2) CAC with 2.8% CaCl2 and 25% Bi2O3 (CACb); 3) CAC with 10% CaCl2 and 25% Bi2O3 (CACb+); or 4) mineral trioxide aggregate (MTA), placed on inserts. Non-exposed cultures served as control. Cell morphology, cell viability, gene expression of alkaline phosphatase (ALP), bone sialoprotein (BSP), and dentin matrix protein 1 (DMP-1), ALP activity, and extracellular matrix mineralization were evaluated. Data were compared using ANOVA (α=5%).

Results: Lower cell density was detected only for MTA and CACb+ compared with Control, with areas showing reduced cell spreading. Cell viability was similar among groups at days one and three (p>0.05). CACb+ and MTA showed the lowest cell viability values at day seven (p>0.05). CACb and CACb+ promoted higher ALP and BSP expression compared with CACz (p<0.05); despite that, all cements supported ALP activity. Matrix mineralization were enhanced in CACb+ and MTA.

Conclusion: In conclusion, CAC with Bi2O3, but not with ZnO, supported the expression of odontoblastic phenotype, but only the composition with 10% CaCl2 promoted mineralized matrix formation, rendering it suitable for dentin-pulp complex repair.
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http://dx.doi.org/10.1590/1678-7757-2019-0105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6886393PMC
December 2019

Cell therapy stimulates bone neoformation in calvaria defects in rats subjected to local irradiation.

Animal Model Exp Med 2019 Sep 1;2(3):169-177. Epub 2019 Jul 1.

Department of Basic and Oral Biology, School of Dentistry of Ribeirão Preto University of São Paulo Ribeirão Preto SP Brazil.

Background: The purpose of the study was to analyze the effect of cell therapy on the repair process in calvaria defects in rats subjected to irradiation.

Methods: Bone marrow mesenchymal cells were characterized for osteoblastic phenotype. Calvariae of male Wistar rats were irradiated (20 Gy) and, after 4 weeks, osteoblastic cells were placed in surgically created defects in irradiated (IRC) and control animals (CC), paired with untreated irradiated (IR) and control (C) animals. After 30 days, histological and microtomographic evaluation was performed to establish significant ( < 0.05) differences among the groups.

Results: Higher alkaline phosphatase detection and activity, along with an increase in mineralized nodules, in the IRC, C and CC groups compared to the IR group, confirmed an osteoblastic phenotype. Histology showed impaired bone neoformation following irradiation, affecting bone marrow composition. Cell therapy in the IRC group improved bone neoformation compared to the IR group. Microtomography revealed increased bone volume, bone surface and trabecular number in IRC group compared to the IR group.

Conclusion: Cell therapy may improve bone neoformation in defects created after irradiation.
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http://dx.doi.org/10.1002/ame2.12073DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6762041PMC
September 2019

Low-level laser therapy enhances the number of osteocytes in calvaria bone defects of ovariectomized rats.

Animal Model Exp Med 2019 Mar 21;2(1):51-57. Epub 2019 Feb 21.

Department of Morphology, Physiology and Basic Pathology School of Dentistry of Ribeirão Preto USP - University of São Paulo Ribeirão Preto SP Brazil.

Background: Osteoporosis can make bone repair difficult. Low-level laser therapy (LLLT) has been shown to be a promising tool for bone neoformation. This study aimed to analyze the effect of LLLT on calvaria bone defects of ovariectomized rats using stereology.

Methods: Fifty-four Wistar rats were subjected to bilateral ovariectomy, and bone defects were created in calvaria after 150 days. The animals were divided into nine groups (n =  6 per group), and 24 hours after the bone defects were created they received 3, 6 or 12 sessions of LLLT at 0, 20 or 30 J/cm, using a 780-nm low-intensity GaAlAs laser. One-way ANOVA followed by Tukey's post hoc test was used for data processing. A difference of  < 0.05 was considered statistically significant. The parameters evaluated were osteocyte density (), total osteocyte number (), trabecular surface density (), and trabecular surface area ().

Results: Data obtained showed that , , and in group G2 rats were significantly different from G1 (0 J/cm) ( < 0.05). Compared to group G4, G5 presented higher values for the parameters and , and G6 presented significantly higher values for almost all the analyzed parameters (, , , and ) ( < 0.05). Compared to group G7, G8 showed a higher value only for the parameter , and G9 showed significantly higher values for parameters , , , and .

Conclusion: We conclude that LLLT stimulated bone neoformation and contributed to an increase in the total number of osteocytes, especially with a laser energy density of 30 J/cm given for 6 and 12 sessions.
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http://dx.doi.org/10.1002/ame2.12056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6431244PMC
March 2019

Effect of grape seed extract (GSE) on functional activity and mineralization of OD-21 and MDPC-23 cell lines.

Braz Oral Res 2019 Feb 11;33:e013. Epub 2019 Feb 11.

Universidade de São Paulo - USP, School of Dentistry of Ribeirão Preto, Department of Basic and Oral Biology, Ribeirão Preto, SP, Brazil.

Recent studies on functional tissue regeneration have focused on substances that favor cell proliferation and differentiation, including the bioactive phenolic compounds present in grape seed extract (GSE). The aim of this investigation was to evaluate the stimulatory potential of GSE in the functional activity of undifferentiated pulp cells and odontoblast-like cells. OD-21 and MDPC-23 cell lines were cultivated in odontogenic medium until subconfluence, seeded in 24-well culture plates in a concentration of 2x104/well and divided into: 1) OD-21 without GSE; 2) OD-21+10 µg/mL of GSE; 3) MDPC-23 without GSE; 4) MDPC-23+10 µg/mL of GSE. Cell proliferation, in situ detection of alkaline phosphatase (ALP) and total protein content were assessed after 3, 7 and 10 days, and mineralization was evaluated after 14 days. The data were analyzed by ANOVA statistical tests set at a 5% level of significance. Results revealed that cell proliferation increased after 10 days, and protein content, after 7 days of culture in MDPC-23 cells. In situ ALP staining intensity was higher in undifferentiated pulp cells and odontoblast-like cells after 7 and 10 days, respectively. A discrete increase in MDPC-23 mineralization after GSE treatment was observed despite OD-21 cells presenting a decrease in mineralized nodule deposits. Data suggest that GSE favors functional activity of differentiated cells more broadly than undifferentiated cells (OD-21). More studies with different concentrations of GSE must be conducted to confirm its benefits to cells regarding dentin regeneration.
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http://dx.doi.org/10.1590/1807-3107bor-2019.vol33.0013DOI Listing
February 2019

Lycopene influences osteoblast functional activity and prevents femur bone loss in female rats submitted to an experimental model of osteoporosis.

J Bone Miner Metab 2019 Jul 24;37(4):658-667. Epub 2018 Oct 24.

Cell Culture Laboratory, Department of Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, Ribeirão Preto, SP, 14040-904, Brazil.

Antioxidant properties of several nutrients may influence bone metabolism, affording protection against damaging effects caused by oxidative stress. Thus, we hypothesized that lycopene may benefit bone tissue metabolism and functional activity of osteoblastic cells from bone marrow of osteoporotic female rats. Wistar rats were ovariectomized and paired with sham animals. In vitro evaluations were performed after 60 days of surgery, when cells were cultured in osteogenic medium and divided in control (C), ovariectomized (OVX) and ovariectomized + 1 μmol/L lycopene (OVXL) groups. Besides, in vivo studies were carried out to evaluate femur bone remodeling by histological and histomorphometric analyses after daily intake of 10 mg/kg of lycopene for 30 and 60 days after ovariectomy. Cell proliferation was significantly higher in OVX and OVXL groups after 10 days of culture. Alkaline phosphatase activity (ALP) was higher in OVXL group in later periods of cell culture, whereas its in situ detection was higher for this group in all experimental periods; nevertheless, mineralization did not show significant differences among the groups. There was a significant upregulation of genes Sp7, Runx2 and Bsp after 3 days and genes Runx2 and Bglap after 10 days from OVXL when compared to OVX. In vivo results demonstrated that daily intake of 10 mg/kg of lycopene for 60 days decreased bone loss in femur epiphysis in ovariectomized rats by maintaining trabecular bone similar to controls. Data obtained suggest that lycopene might benefit the functional activity of osteoblastic cells from ovariectomized rats, as well as avoid further bone resorption.
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http://dx.doi.org/10.1007/s00774-018-0970-8DOI Listing
July 2019

Menopause transition promotes distinct modulation of mRNAs and miRNAs expression in calvaria and bone marrow osteoblastic cells.

Cell Biol Int 2018 Jan 17;42(1):12-24. Epub 2017 Jul 17.

Department of Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.

Investigation on functional genome research may contribute to the knowledge of functional roles of different mRNAs and miRNAs in bone cells of osteoporotic animals. Currently, few studies indicate the changes in gene modulation that osteoporosis causes in osteoblastic cells from different sites. Thus, the purpose of this investigation was to evaluate cell viability, alkaline phosphatase activity and modulation of mRNAs/miRNAs in osteoblastic cells from calvaria and bone marrow by means of microarray technology. Wistar female rats were divided in sham operated and ovariectomized groups. After 150 days of ovariectomy, cells were isolated from both sites to perform cell culture. Results showed that calvaria cells from ovariectomized rats had a decrease in viability when compared to control groups and to bone marrow cells from osteoporotic rats after 3 days. Alkaline phosphatase activity decreased in calvaria cells from ovariectomized rats whereas it was increased in bone marrow osteoblastic cells in the same group. Microarray data analysis showed 5447 differentially expressed mRNAs and 82 differentially expressed miRNAs in calvaria cells. The same way, 4399 mRNAs and 54 miRNAs were expressed in bone marrow cells. mRNAs associated with bone metabolism such as Anxa5, Sp7, Spp1, Notch1 were distinctively modulated in both sites, as well as miRNAs such as miR-350, miR-542-3p, miR-204-5p, and miR-30e-3p. The RNA species identified in this study could be further used as targets for treatment or prevention of osteoporosis.
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http://dx.doi.org/10.1002/cbin.10802DOI Listing
January 2018

Oxidative Nanopatterning of Titanium Surface Influences mRNA and MicroRNA Expression in Human Alveolar Bone Osteoblastic Cells.

Int J Biomater 2016 21;2016:9169371. Epub 2016 Apr 21.

Cell Culture Laboratory, Department of Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, University of São Paulo, 14040-904 Ribeirão Preto, SP, Brazil.

Titanium implants have been extensively used in orthopedic and dental applications. It is well known that micro- and nanoscale surface features of biomaterials affect cellular events that control implant-host tissue interactions. To improve our understanding of how multiscale surface features affect cell behavior, we used microarrays to evaluate the transcriptional profile of osteoblastic cells from human alveolar bone cultured on engineered titanium surfaces, exhibiting the following topographies: nanotexture (N), nano+submicrotexture (NS), and rough microtexture (MR), obtained by modulating experimental parameters (temperature and solution composition) of a simple yet efficient chemical treatment with a H2SO4/H2O2 solution. Biochemical assays showed that cell culture proliferation augmented after 10 days, and cell viability increased gradually over 14 days. Among the treated surfaces, we observed an increase of alkaline phosphatase activity as a function of the surface texture, with higher activity shown by cells adhering onto nanotextured surfaces. Nevertheless, the rough microtexture group showed higher amounts of calcium than nanotextured group. Microarray data showed differential expression of 716 mRNAs and 32 microRNAs with functions associated with osteogenesis. Results suggest that oxidative nanopatterning of titanium surfaces induces changes in the metabolism of osteoblastic cells and contribute to the explanation of the mechanisms that control cell responses to micro- and nanoengineered surfaces.
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http://dx.doi.org/10.1155/2016/9169371DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4856946PMC
May 2016

Low-level laser therapy improves bone formation: stereology findings for osteoporosis in rat model.

Lasers Med Sci 2015 Jul 3;30(5):1599-607. Epub 2015 Jun 3.

Department of Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, USP-University of São Paulo, Ribeirão Preto, SP, Brazil.

Low-level laser therapy (LLLT) benefits bone metabolism, but its use needs to be standardized. We evaluated the effects of LLLT on bone defects in calvaria of ovariectomized rats. Stereology was used to calculate tissue repair volume (V tr ), density of trabecular bone volume (Vv t ), total volume of newly formed trabecular bone (Vtot), and the area occupied by collagen fibers (A C ). Fifty-four Wistar rats were submitted to bilateral ovariectomy, and bone defects were created in calvaria after 150 days. The animals were divided into nine groups (n = 6), and 24 h after defects, the treatment started with a 780-nm low-intensity GaAlAs laser: G1, G2, and G3 received 3 sessions of 0, 20, and 30 J/cm(2) respectively; G4, G5, and G6 received 6 sessions of 0, 20, and 30 J/cm(2), respectively; and G7, G8, and G9 received 12 sessions of 0, 20, and 30 J/cm(2), respectively. A normal distribution was found for all of the data. The test used to verify the normality was the Kolmogorov-Smirnov (KS, p > 0.05). The one-way ANOVA followed by Tukey's post hoc test was used for data processing. A difference of p < 0.05 was considered statistically significant. Groups G2 and G1 showed significance for V tr , Vv t , Vtot, and (A C ). Results were significant for (Vv t ) and (Vtot) between G3 and G1. There were no significant results between G5 and G4 as well as between G8 and G7. Groups G6 and G4 results showed statistical difference for V tr , Vv t , Vtot, and (A C ). Groups G9 and G7 showed significance for V tr , Vv t , Vtot, and (A C ). In conclusion, there was new bone formation in the groups that received 20 and 30 J/cm(2) when compared to control groups, but over time, the dose of 30 J/cm(2) showed better stereological parameters when compared to 20 J/cm(2).
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http://dx.doi.org/10.1007/s10103-015-1773-yDOI Listing
July 2015

Undifferentiated pulp cells and odontoblast-like cells share genes involved in the process of odontogenesis.

Arch Oral Biol 2015 Apr 19;60(4):593-9. Epub 2014 Oct 19.

Cell Culture Laboratory - Department of Morphology, Stomatology and Physiology, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil. Electronic address:

Objective: Expression of a large number of genes during differentiation of undifferentiated pulp cells into odontoblastic cells is still unknown, hence the aim of this investigation was to compare undifferentiated pulp cells (OD-21) and odontoblast-like cells (MDPC-23) through the assessment of cell stimulation and gene expression profiling.

Design: The cells were cultured and after the experimental periods, there were evaluated cell proliferation and viability as well as alkaline phosphatase activity (ALP) and mineralization nodules. To evaluate gene expression it was used fluorescence cDNA microarray technology in addition to bioinformatics programmes such as SAM (significance analysis of microarrays). Gene expression was validated by Real Time PCR (qPCR).

Results: The results showed that viability was above 80% in both cells, cell proliferation and ALP activity was higher in MDPC-23 cells and mineralization nodules were present only in the cultures of odontoblast-like cells. There were observed genes associated to odontogenesis with similar behaviour in both cell types, such as Il10, Traf6, Lef1 and Hspa8. Regions of the heatmap showed differences in induction and repression of genes such as Jak2 and Fas.

Conclusion: OD-21 cells share many genes with similar behaviour to MDPC-23 cells, suggesting their potential to differentiate into odontoblasts.
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http://dx.doi.org/10.1016/j.archoralbio.2014.09.015DOI Listing
April 2015

In vitro evaluation of the odontogenic potential of mouse undifferentiated pulp cells.

Braz Dent J 2012 ;23(4):328-36

Ribeirão Preto Dental School, University of São Paulo, Ribeirão Preto, SP, Brazil.

The aim of this study was to evaluate the odontogenic potential of undifferentiated pulp cells (OD-21 cell line) through chemical stimuli in vitro. Cells were divided into uninduced cells (OD-21), induced cells (OD-21 cultured in supplemented medium/OD-21+OM) and odontoblast-like cells (MDPC-23 cell line). After 3, 7, 10 and 14 days of culture, it was evaluated: proliferation and cell viability, alkaline phosphatase activity, total protein content, mineralization, immunolocalization of dentin matrix acidic phosphoprotein 1 (DMP1), alkaline phosphatase (ALP) and osteopontin (OPN) and quantification of genes ALP, OSTERIX (Osx), DMP1 and runt-related transcription factor 2 (RUNX2) through real-time polymerase chain reaction (PCR). Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests (p<0.05). There was a decrease in cell proliferation in OD-21 + OM, whereas cell viability was similar in all groups, except at 7 days. The amount of total protein was higher in group OD-21 + OM in all periods; the same occurred with ALP activity after 10 days when compared with OD-21, with no significant differences from the MDPC-23 group. Mineralization was higher in OD-21+OM when compared with the negative control. Immunolocalization demonstrated that DMP1 and ALP were highly expressed in MDPC-23 cells and OD-21 + OM cells, whereas OPN was high in all groups. Real-time PCR revealed that DMP1 and ALP expression was higher in MDPC-23 cell cultures, whereas RUNX2 was lower for these cells and higher for OD-21 negative control. Osx expression was lower for OD-21 + OM. These results suggest that OD-21 undifferentiated pulp cells have odontogenic potential and could be used in dental tissue engineering.
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http://dx.doi.org/10.1590/s0103-64402012000400004DOI Listing
December 2013

Low-level laser therapy influences mouse odontoblast-like cell response in vitro.

Photomed Laser Surg 2012 Apr 29;30(4):206-13. Epub 2012 Feb 29.

School of Dentistry of Ribeirão Preto, Cell Culture Laboratory-Department of Morphology, Stomatology and Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil.

Objective: The purpose of this study was to analyze the influence of two different irradiation times with 85 mW/cm(2) 830 nm laser on the behavior of mouse odontoblast-like cells.

Background Data: The use of low-level laser therapy (LLLT) to stimulate pulp tissue is a reality, but few reports relate odontoblastic responses to irradiation in in vitro models.

Methods: Odontoblast-like cells (MDPC-23) were cultivated and divided into three groups: control/nonirradiated (group 1); or irradiated with 85 mW/cm(2), 830 nm laser for 10 sec (0.8 J/cm(2)) (group 2); or for 50 sec (4.2 J/cm(2)) (group 3) with a wavelength of 830 nm. After 3, 7, and 10 days, it was analyzed: growth curve and cell viability, total protein content, alkaline phosphatase (ALP) activity, calcified nodules detection and quantification, collagen immunolocalization, vascular endothelial growth factor (VEGF) expression, and real-time polymerase chain reaction (PCR) for DMP1 gene. Data were analyzed by Kruskall-Wallis test (α=0.05).

Results: Cell growth was smaller in group 2 (p<0.01), whereas viability was similar in all groups and at all periods. Total protein content and ALP activity increased on the 10th day with 0.8 J/cm(2) (p<0.01), as well as the detection and quantification of mineralization nodules (p<0.05), collagen, and VEGF expression (p<0.01). The expression of DMP1 increased in all groups (p<0.05) compared with control at 3 days, except for 0.8 J/cm(2) at 3 days and control at 10 days.

Conclusions: LLLT influenced the behavior of odontoblast-like cells; the shorter time/smallest energy density promoted the expression of odontoblastic phenotype in a more significant way.
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http://dx.doi.org/10.1089/pho.2011.3087DOI Listing
April 2012

Osteointegration of autogenous bone graft associated with osteoblastic cells under treatment with caffeine.

Implant Dent 2011 Oct;20(5):369-73

Department of Morphology, Stomatology and Physiology, Dentistry School, University of São Paulo-USP, Ribeirão Preto, São Paulo, Brazil.

Purpose: The present study investigated osteointegration of autogenous bone (AB) from calvaria graft associated with osteoblastic cells (OC) in bone defects in rats subjected to daily administration of caffeine.

Materials And Methods: Male rats received daily intraperitoneal injection of 1.5% caffeine (0.2 mL/100 g body weight) or saline solution for 30 days. Then they were anesthetized, submitted to the extraction of the upper right incisor, and implanted with AB only and AB + OC. The animals were killed on 7th, 21st, and 42nd days after surgery, and their maxilla were processed for obtaining semiserial sections (5 μm) stained with hematoxylin and eosin. Through image analysis system, the bone volume and the quality of graft in adjacent areas were estimated.

Results: The results showed that in caffeine treatment, the AB + OC graft showed no foreign body and acute inflammatory reactions inside the defect when compared to AB. The histometric results revealed that the association AB + OC produced significant increase (10%-15%) in bone volume in later experimental period (42 days) when compared with saline solution group (P ≤ 0.01).

Conclusions: It was concluded that the association of AB from calvaria + OC demonstrated progressive osteointegration and accelerated the repair of bone defects in animals treated with daily caffeine.
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http://dx.doi.org/10.1097/ID.0b013e31822b9b53DOI Listing
October 2011

Osteogenic potential of autogenous bone associated with bone marrow osteoblastic cells in bony defects: a histomorphometric study.

Implant Dent 2009 Dec;18(6):521-9

Department of Morphology, Stomatology and Physiology, Dentistry School, University of São Paulo-USP, 14040-904, Ribeirão Preto, São Paulo, Brazil.

Purpose: Because of limitations of autogenous grafts, allografts, xenografts, alloplasts, and hydroxyapatite as graft materials, researchers have been using bone tissue engineering as a strategy for bone regeneration. The aim of this work was to study the effect of bone tissue engineering, associating bone marrow osteoblastic cells, and autogenous bone in defects created by dental extraction in rats.

Materials And Methods: Eighty male rats from 250 to 300 g were anesthetized, submitted to the extraction of the superior incisor, and divided in control group (C), implanted with osteoblastic cells (OC), autogenous bone (AB), and osteoblastic cells + autogenous bone (OC + AB). The animals were killed on 10th and 20th days after surgery and their maxilla were processed for obtaining fine semiserial sections (5 mum), and then stained with hematoxylin-eosin. Through image analysis system, bone volume in areas adjacent to the implants was estimated.

Results: The histometric results revealed that the association OC + AB produced significant increase (10%-15%) of bone in both experimental periods when compared with the control group (P < or = 0.01).

Conclusions: Osteoblastic cells associated with autogenous bone accelerated the repair of bone defect, and the action of the osteoblastic cells was more effective until the 10th day and of the autogenous bone after this period.
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http://dx.doi.org/10.1097/ID.0b013e3181b8e53cDOI Listing
December 2009

Human alveolar bone-derived cell-culture behaviour on biodegradable poly(L-lactic Acid).

J Biomater Sci Polym Ed 2009 ;20(2):167-79

Department of Morphology, Stomatology and Physiology, School of Dentistry of Ribeirão Preto, University of São Paulo (USP), Av. do Café, s/n, 14040-904, Ribeirão Preto, SP, Brazil.

Poly(L-lactic acid) (PLA) is a polymer of great technological interest, whose excellent mechanical properties, thermal plasticity and bioresorbability render it potentially useful for environmental applications, as a biodegradable plastic and as a biocompatible material in biomedicine. The interactions between an implant material surface and host cells play central roles in the integration, biological performance and clinical success of implanted biomedical devices. Osteoblasts from human alveolar bone were chosen to investigate the cell behaviour when in contact with PLA discs. Cell morphology and adhesion through osteopontin (OPN) and fibronectin (FN) expression were evaluated in the initial osteogenesis, as well as cell proliferation, alkaline phosphatase activity and bone nodule formation. It was shown that the polymer favoured cell attachment. Cell proliferation increased until 21 days but in a smaller rate when compared to the control group. On the other hand, ALP activity and bone mineralization were not enhanced by the polymer. It is suggested that this polymer favours cell adhesion in the early osteogenesis in vitro, but it does not enhance differentiation and mineralization.
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http://dx.doi.org/10.1163/156856209X404479DOI Listing
April 2009

Tooth pigmentation caused by bilirubin: a case report and histological evaluation.

Spec Care Dentist 2008 Nov-Dec;28(6):254-7

Department of Pediatric Clinics, Preventive and Social Dentistry, University of São Paulo, São Paulo, Brazil.

Systemic disorders in pediatric patients, such as congenital biliary atresia, acute liver failure, and biliary hypoplasia, may be the indications for a need of liver transplantation. One of the manifestations of these disorders is the elevated serum levels of bilirubin (hyperbiliru-binemia), a product of hemoglobin degradation, which is deposited in different tissues, including mineralized and soft tissues. When hyperbilirubinemia occurs during the period of dental development, these teeth can develop a green coloration, which remains permanently, because, after maturation, these tissues loose their metabolic activity. This case report describes a 9-year-old girl who required a liver transplant due to biliary atresia when she was three years old. Some of her pigmented teeth needed extraction and afterwards were submitted for histological analysis and compared with sound teeth.
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http://dx.doi.org/10.1111/j.1754-4505.2008.00048.xDOI Listing
February 2009

Chemical synthesis and in vitro biocompatibility tests of poly (L-lactic acid).

J Biomed Mater Res A 2007 Oct;83(1):209-15

Materials Engineering-UFRGS, Av. Bento Gonçalves 9500, Setor IV-Edif. 74-123, 91501-970 Porto Alegre, Brazil.

Polylactic acid is a polymer of great technological interest, whose excellent mechanical properties, thermal plasticity, and bioresorbability render it potentially useful for environmental applications, as a biodegradable plastic and as a biocompatible material in biomedicine. This article discusses the synthesis and characterization of poly-L-lactic acid, obtained through two synthetic routes: direct polycondensation reactions without organic solvents, and in a supercritical medium. Tin complexes were used as catalysts in both polymerization reactions. The polymers were characterized by (1)HNMR, IR, GPC, DSC, and TGA techniques. In vitro biocompatibility tests were performed with human alveolar bone osteoblasts and there were assessed cell adhesion, proliferation and viability. The poly condensation reaction proved to be an excellent synthetic route to produce PLA polymers with different molar mass. The formation of polymers from lactic acid monomer was confirmed through techniques utilized. It was observed that cell adhesion and viability was not disturbed by the presence of the polymer, although the proliferation rate was decreased when compared to control.
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http://dx.doi.org/10.1002/jbm.a.31210DOI Listing
October 2007

Alcohol intake and osseointegration around implants: a histometric and scanning electron microscopy study.

Implant Dent 2004 Sep;13(3):238-44

Histology Department, Dentistry School of University of São Paulo-USP, Brazil.

Alveolar wound healing can be modified by local and systemic factors. The aim of this study was to evaluate the possible effect of alcoholic beverage administration (sugarcane brandy) on reparative bone formation around hydroxyapatite/tricalcium phosphate implants inside the alveolar socket. Male Wistar rats had their upper right incisors extracted and the bioceramic granules implanted in the alveoli. The animals received increasing concentrations of brandy until 30 degrees Gay-Lussac was achieved starting 30 days before dental extraction and maintained for periods varying from 1 hour to 6 weeks, until sacrifice. Blood alcohol concentration analysis was performed as well as histological and histometric analysis through light and scanning electron microscopy to examine the relation between alveolar healing components, including new bone trabeculae, and the implants. Blood alcohol concentration was significantly higher in treated animals compared with controls. A significant delay in reparative bone formation was detected in the alveolus of alcoholic rats by a histometric differential point counting method, whereas the presence of the bioceramic in the alveolar socket improved alveolar wound healing in alcohol-treated rats. It is suggested that the osteoconductive properties of this bioceramic accelerated alveolar wound healing in alcoholic rats.
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http://dx.doi.org/10.1097/01.id.0000136918.05763.78DOI Listing
September 2004