Carlos Augusto Galvão Barboza

Effect of low-level laser therapy on mesenchymal stem cell proliferation: a systematic review

Low-level laser therapy (LLLT) has been used in several in vitro experiments in order to stimulate cell proliferation. Cells such as fibroblasts, keratinocytes, lymphocytes, and osteoblasts have shown increased proliferation when submitted to laser irradiation, although little is known about the effects of LLLT on stem cells. This study aims to assess, through a systematic literature review, the effects of LLLT on the in vitro proliferation of mesenchymal stem cells. Using six different terms, we conducted an electronic search in PubMed/Medline database for articles published in the last twelve years. From 463 references obtained, only 19 papers met the search criteria and were included in this review. The analysis of the papers showed a concentration of experiments using LLLT on stem cells derived from bone marrow, dental pulp, periodontal ligament, and adipose tissue. Several protocols were used to irradiate the cells, with variations on wavelength, power density, radiation time, and state of light polarization. Most studies demonstrated an increase in the proliferation rate of the irradiated cells. It can be concluded that the laser therapy positively influences the in vitro proliferation of stem cells studied, being necessary to carry out further experiments on other cell types and to uniform the methodological designs.

Proliferating Cell Nuclear Antigen (PCNA) and p53 Protein Expression in Ameloblastoma and Adenomatoid Odontogenic Tumor

In this study, proliferating cell nuclear antigen (PCNA) and p53 protein expressions were analyzed in 16 cases of ameloblastoma and 8 cases of adenomatoid odontogenic tumor (AOT). The cases of ameloblastoma consisted of solid type tumors and histologic arrangements of different subtypes were observed. In some specimens, more than one histologic subtype was identified in the same lesion, and each tumor was categorized according to the predominant cell pattern. The odontogenic tumors were grouped as follows: follicular ameloblastoma (n=7), plexiform ameloblastoma (n=4), acanthomatous + follicular ameloblastoma (n=3), basal cell ameloblastoma (n=2), adenomatoid odontogenic tumor (n=8). PCNA immunohistochemical expression revealed stronger quantitative labeling index for the follicular ameloblastoma, while for p53 protein the strongest quantitative labeling index was detected in the plexiform type. Nevertheless, statistical analysis using ANOVA and Tukeys test did not detect significant differences (p>0.05) among the histologic subtypes of ameloblastoma. The findings of this study suggest that the different histologic patterns of ameloblastoma did not show a direct correlation with their clinical behavior and consequently with the prognosis of the cases. The results also indicated that the ameloblastoma has greater proliferative potential than the AOT, which can contribute to explain its more aggressive and invasive characteristics.

Experimental Considerations Concerning the Use of Stem Cells and Tissue Engineering for Facial Nerve Regeneration: A Systematic Review

PURPOSE Peripheral nerve trauma results in functional loss in the innervated organ, and recovery without surgical intervention is rare. Many surgical techniques can be used for repair in experimental models. The authors investigated the source and delivery method of stem cells in experimental outcomes, seeking to clarify whether stem cells must be differentiated in the injured facial nerve and improve the regenerative process. MATERIALS AND METHODS The following key terms were used: nervous regeneration, nerve regeneration, facial nerve regeneration, stem cells, embryonic stem cells, fetal stem cells, adult stem cells, facial nerve, facial nerve trauma, and facial nerve traumatism. The search was restricted to experimental studies that applied stem cell therapy and tissue engineering for nerve repair. RESULTS Eight studies meeting the inclusion criteria were reviewed. Different sources of stem and precursor cells were explored (bone marrow mesenchymal stem cells, adipose-derived stem cells, dental pulp cells, and neural stem cells) for their potential application in the scenario of facial nerve injuries. Different material conduits (vases, collagen, and polyglycolic acid) were used as bridges. Immunochemistry and electrophysiology are the principal methods for analyzing regenerative effects. Although recent studies have shown that stem cells can act as a promising bridge for nerve repair, considerable optimization of these therapies will be required for their potential to be realized in a clinical setting. CONCLUSION Based on these studies, the use of stem cells derived from different sources presents promising results related to facial nerve regeneration and produces effective functional results. The use of tubes also optimizes nerve repair, thus promoting greater myelination and axonal growth of peripheral nerves.

Matrix metalloproteinase‐8 levels in periodontal disease patients: A systematic review

Periodontal disease is characterized as a disorder of the oral microbiota resulting in an immune response which, in turn, leads to the destruction of periodontal tissue. Matrix metalloproteinase-8 (MMP-8) has been reported as the major metalloproteinase involved in periodontal disease, being present at high levels in gingival crevicular fluid and salivary fluid (SF). The aim of this systematic review was to evaluate the scientific literature regarding the expression of MMP-8 in gingival crevicular fluid and SF in patients with periodontal disease, analyzing its validity as a possible biomarker in the diagnosis of periodontal disease. A systematic review of the literature was performed using the PubMed/Medline, CENTRAL and Science Direct databases. Studies concerning the use of MMP-8 in the diagnosis of periodontal disease that evaluated its effectiveness as a biomarker for periodontal disease were selected. The search strategy provided a total of 6483 studies. After selection, six articles met all the inclusion criteria and were included in the present systematic review. The studies demonstrated significantly higher concentrations of MMP-8 in patients with periodontal disease compared with controls, as well as in patients presenting more advanced stages of periodontal disease. The findings on higher MMP-8 concentrations in patients with periodontal disease compared with controls imply the potential adjunctive use of MMP-8 in the diagnosis of periodontal disease.

Effect of a cryopreservation protocol on the proliferation of stem cells from human exfoliated deciduous teeth

Abstract Objective: The aim of the present study was to evaluate the influence of a cryopreservation protocol on the proliferation and viability of stem cells from human exfoliated deciduous teeth (SHEDs). Materials and methods: Cells from the pulp of three deciduous teeth were isolated and characterized to confirm their stem cell nature. In second passage, part of the cells were submitted to normal conditions of cell culture (Control group), while part of the cells were maintained in 10% DMSO diluted in foetal bovine serum and submitted to the following cryopreservation protocol: 2 h at 4 °C, 18 h at −20 °C and then at −80 °C for two intervals (30 days – Cryopreservation I; and 180 days Cryopreservation II). Cell proliferation and cell cycle were evaluated at intervals of 24, 48 and 72 h after plating, and apoptosis-related events were analyzed at 72 h. Results: All groups exhibited an increase in the number of cells, and no significant differences between the cryopreserved and control groups were observed (p > .05). The distribution of cells in the cell cycle phases was consistent with cell proliferation, and the percentage of viable cells was higher than 99% in all groups, indicating that cell viability was not affected by the cryopreservation protocol throughout the experiment. Conclusion: The proposed cryopreservation protocol is adequate for the storage of SHED, permitting their use in future experimental studies.

Influência de um protocolo de criopreservação no rendimento in vitro de células-tronco derivadas do tecido adiposo

Background: Adipose tissue obtained by liposuction may be an accessible source of stem cells for future clinical application in tissue regeneration. Cryopreservation maintains stem cells in a live state for long periods of time, without impairing their function. The aim of this study was to assess the effect of a cryopreservation protocol on the proliferation of adipose-derived stem cells. Methods: Fragments of mouse adipose tissue were subjected to enzymatic digestion in order to isolate cells that were then cultured in minimum essential medium (α-MEM) supplemented with 10% fetal bovine serum (FBS). Cells were main tained at 37°C in 5% carbon dioxide (CO 2 ). At the first passage, an aliquot of 1 × 10 6 cells was cryopreserved in FBS with 10% dimethylsulfoxide (DMSO) for 30 days, whereas the remaining cells were seeded and maintained in culture. When these cells reached the third passage, the 2 groups of cells (cryopreserved and non-cryopreserved) were seeded for experiments. Cell viability and proliferation curves were established at intervals of 24, 48, and 72 hours by counting cells with a hemocytometer and MTT assay. Nuclear morphology was assessed by DAPI staining. The data were statistically analyzed, with a significance level of 5%. Results: Increasing cellular proliferation was observed in both groups, with no significant difference throughout the experiment (P > 0.05). There was no significant change in cell viability and signs of nuclear damage were not detected in both the groups studied. Conclusions: The cryopreservation protocol analyzed was effective for maintaining the integrity of adipose-derived stem cells, allowing their storage for later use.

Use of Clinical Cases in a Virtual Learning Environment as an Approach to Teaching Human Embryology

El objetivo del trabajo fue evaluar la eficacia de un metodo de ensenanza de la Embriologia en ambiente virtual. Para complementar el contenido discutido en clases, fueron organizados en un blog, casos clinicos abordando seis ejes tematicos de Embriologia Humana. Articulos cientificos estuvieron disponibles para consolidacion de los contenidos teoricos y el eje etico-humanistico fue abordado en foros de discusion. Al final del semestre la media de las notas de los alumnos fue comparada con la media de un semestre anterior donde la metodologia no fue utilizada. La percepcion de los alumnos con relacion a la eficacia del uso del blog en el aprendizaje fue evaluada a traves de un cuestionario electronico. Se observo aumento considerable de la media de las notas al ser comparadas con las notas del periodo lectivo anterior. El analisis de los cuestionarios revelo que los alumnos consideraron el blog como un instrumento practico y util de aprendizaje. Se concluye que esta metodologia represento una herramienta eficiente em la ensenanza de los contenidos de Embriologia Humana.

CONDUTA ODONTOLÓGICA EM PACIENTES HIPERTENSOS

Objective: The aim of this systematic review was to evaluate the literature on dental care provided to hypertensive individuals, in order to establish a better approach of the clinic dental care for these patients. Material and methods: Bibliographical searches were carried out in the following electronic databases: MEDLINE, LILACS, BBO, and Science Direct, including the papers published in the period from 2006 to 2011. Results: The literature reports that the use of antihypertensive drugs may lead to oral complications such as decrease in salivary secretion and increased gingival tissue. Furthermore, the incorrect use of local anesthetics, with or without a vasoconstrictor, can further worsen the patients hypertension. Conclusion: It is very important to emphasize the need of knowing the possible local and/or systemic complications due to drug therapy used in hypertensive individuals, so that dental treatment can be provided in a safe and effective way in these patients. DESCRIPTORS Hypertension. Oral Manifestations. Dental Care.

Influência da vitamina D na atividade osteoclástica em um modelo de cultura de órgãos ósseos

INTRODUCAO: A remodelacao ossea e regulada por varias citocinas e hormonios, como a vitamina D3. Essa vitamina, em particular, regula positiva e negativamente a expressao do ligante do receptor ativador do fator nuclear kappa-B (RANKL) e da osteoprotegerina (OPG), respectivamente, e e usada como um indutor da formacao de osteoclastos in vitro. OBJETIVO: Estudar o efeito da vitamina D (VitD) sobre a atividade osteoclastica em cultura de calvarias. MATERIAL E METODO: Fragmentos de calvaria de camundongos foram cultivados com meio basico (controle) ou com meio contendo VitD (10 nM: baixa dose; 100 nM: alta dose). Apos os intervalos de 24, 48 e 72 horas, o meio de cultura foi coletado para dosagem de calcio e os fragmentos foram fixados para analise em microscopia confocal. RESULTADOS: Observou-se que a adicao de VitD nas duas dosagens promoveu aumento nos niveis de calcio no meio, porem so foram encontradas diferencas estatisticamente significativas entre alta e baixa dose no intervalo de 24 horas. Na microscopia, foram observadas areas de desmineralizacao mais amplas nos fragmentos de calvaria cultivados com altas doses de VitD. CONCLUSAO: A VitD promove aumento da atividade osteoclastica in vitro, de modo concentracao-efeito.

Matrix metalloproteinase-8 analysis in patients with periodontal disease with prediabetes or type 2 diabetes mellitus: A systematic review

OBJECTIVES The objective of this systematic review was to evaluate information on the levels of MMP-8 in patients diagnosed with prediabetes or type 2 diabetes mellitus with periodontal disease, analyzing its validity as a possible biomarker for the diagnosis and progression of periodontal disease (PD). METHODS A systematic search of the following databases was performed: PubMed/Medline, CENTRAL (The Cochrane Library), EMBASE and Web of Science. Studies involving the evaluation of MMP-8 in patients with prediabetes or patients presenting type 2 diabetes mellitus concomitantly with PD were selected. The evaluation of the methodological quality of the selected studies was based on the methodological bias risk analysis (QUADAS-2). RESULTS Eight of the initially identified 2683 articles were selected. In all the selected studies, evaluator calibration and the use of clear methods for patient diagnosis with periodontal disease were present. Studies have demonstrated significantly higher MMP-8 concentrations in PD patients compared to controls, as well as in patients presenting more advanced stages of PD. However, controversies regarding MMP-8 levels in prediabetes/diabetes type 2 patients with PD. CONCLUSIONS Higher MMP-8 levels in patients with PD compared to controls imply the potential use of MMP-8 in the diagnosis of PD. The influence of patient glycemic state, as well as medications these patients make use of, are factors that possibly contribute to the modulation of MMP-8 concentrations in patients with diabetes and should be analyzed, aiming at a better understanding of the relationship between glycemic state and MMP-8 levels in patients with PD.