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2.
Actual. osteol ; 16(2): [132]-[140], mayo.-ago. 2020. ilus
Article in Spanish | LILACS | ID: biblio-1129806

ABSTRACT

La oxitocina (OXT) como la arginina-vasopresina (AVP) son dos hormonas primitivas secretadas por la hipófisis posterior. Sus receptores están mucho más ampliamente distribuidos en el organismo de lo que se pensaba originalmente, incluido el hueso. En los estudios preclínicos, la OXT ha mostrado ser anabólica para el hueso, promoviendo la osteogénesis sobre la adipogénesis y favoreciendo la actividad osteoblástica sobre la osteoclástica. Tanto los osteoblastos como los osteoclastos tienen receptores para la OXT, y los efectos de los estrógenos sobre la masa ósea en ratones está mediada por lo menos en parte por la OXT. El mecanismo preciso por el cual la activación de los receptores de oxitocina (OXTR) se traduce en un incremento de la formación ósea permanece poco claro. La AVP también podría afectar el esqueleto en forma directa. Dos de los receptores de la AVP, V1a y V2 están expresados en osteoblastos y osteoclastos. La inyección de AVP en ratones de tipo salvaje aumenta la formación osteoclastos que producen resorción y reduce los osteoblastos formadores de hueso. En forma opuesta, la exposición de precursores osteoblásticos a antagonistas de los receptores V1a o V2, incrementan la osteoblastogénesis, como también lo hace la deleción genética del receptor V1a. (AU)


Both oxytocin (OXT) and argininevasopressin (AVP) are primitive hormones secreted by the posterior pituitary gland. OXT receptors are much more widely distributed in the body than originally thought, including in bone. In preclinical studies, OXT has been shown to be anabolic for bone, promoting osteogenesis over adipogenesis and favoring osteoblastic over osteoclastic activity. Both osteoblasts and osteoclasts have receptors for OXT, and the effects of estrogen on bone mass in mice is mediated at least in part by OXT. The precise mechanism by which the activation of oxytocin receptors (OXTRs) results in an increase in bone formation remains unclear. AVP could also have direct actions on the skeleton. The two AVP receptors, V1a and V2, are expressed in osteoblasts and osteoclasts. Injection of AVP in wild-type mice increases the formation of osteoclasts increasing bone resorption, and reduces bone-forming osteoblasts. On the contrary, the exposure of osteoblastic precursors to V1a and V2 antagonists increase osteoblastogenesis, the same as the genetic deletion of the V1a receptor. (AU)


Subject(s)
Humans , Animals , Mice , Pituitary Hormones, Posterior/biosynthesis , Arginine Vasopressin/adverse effects , Oxytocin/therapeutic use , Osteoblasts/physiology , Osteoclasts/physiology , Osteogenesis , Osteoporosis/therapy , Pituitary Hormones, Posterior/physiology , Arginine Vasopressin/antagonists & inhibitors , Arginine Vasopressin/biosynthesis , Arginine Vasopressin/physiology , Arginine Vasopressin/therapeutic use , Oxytocin/biosynthesis , Oxytocin/adverse effects , Oxytocin/physiology , Signal Transduction , Bone Density , Bone Density/drug effects , Receptors, Oxytocin/biosynthesis , Receptors, Oxytocin/physiology , Estradiol/therapeutic use , Estrogens/physiology
3.
J. appl. oral sci ; 28: e20190156, 2020. graf
Article in English | LILACS, BBO | ID: biblio-1090765

ABSTRACT

Abstract Objective The present study aimed to investigate the participation of focal adhesion kinases (FAK) in interactions between osteoblastic cells and titanium (Ti) surfaces with three different topographies, namely, untreated (US), microstructured (MS), and nanostructured (NS). Methodology Osteoblasts harvested from the calvarial bones of 3-day-old rats were cultured on US, MS and NS discs in the presence of PF-573228 (FAK inhibitor) to evaluate osteoblastic differentiation. After 24 h, we evaluated osteoblast morphology and vinculin expression, and on day 10, the following parameters: gene expression of osteoblastic markers and integrin signaling components, FAK protein expression and alkaline phosphatase (ALP) activity. A smooth surface, porosities at the microscale level, and nanocavities were observed in US, MS, and NS, respectively. Results FAK inhibition decreased the number of filopodia in cells grown on US and MS compared with that in NS. FAK inhibition decreased the gene expression of Alp, bone sialoprotein, osteocalcin, and ALP activity in cells grown on all evaluated surfaces. FAK inhibition did not affect the gene expression of Fak, integrin alpha 1 ( Itga1 ) and integrin beta 1 ( Itgb1 ) in cells grown on MS, increased the gene expression of Fak in cells grown on NS, and increased the gene expression of Itga1 and Itgb1 in cells grown on US and NS. Moreover, FAK protein expression decreased in cells cultured on US but increased in cells cultured on MS and NS after FAK inhibition; no difference in the expression of vinculin was observed among cells grown on all surfaces. Conclusions Our data demonstrate the relevance of FAK in the interactions between osteoblastic cells and Ti surfaces regardless of surface topography. Nanotopography positively regulated FAK expression and integrin signaling pathway components during osteoblast differentiation. In this context, the development of Ti surfaces with the ability to upregulate FAK activity could positively impact the process of implant osseointegration.


Subject(s)
Animals , Osteoblasts/drug effects , Sulfones/pharmacology , Titanium/chemistry , Quinolones/pharmacology , Focal Adhesion Protein-Tyrosine Kinases/antagonists & inhibitors , Osteoblasts/physiology , Sulfones/chemistry , Surface Properties , Microscopy, Electron, Scanning , Signal Transduction , Gene Expression , Integrins/analysis , Cell Differentiation/drug effects , Cells, Cultured , Osseointegration/drug effects , Rats, Wistar , Quinolones/chemistry , Cell Proliferation/drug effects , Focal Adhesion Protein-Tyrosine Kinases/analysis , Focal Adhesion Protein-Tyrosine Kinases/chemistry , Real-Time Polymerase Chain Reaction
4.
Chinese Journal of Traumatology ; (6): 314-318, 2020.
Article in English | WPRIM | ID: wpr-879643

ABSTRACT

In this paper, we review the results of previous studies and summarize the effects of various factors on the regulation of bone metabolism in traumatic bone infections. Infection-related bone destruction incorporates pathogens and iatrogenic factors in the process of bone resorption dominated by the skeletal and immune systems. The development of bone immunology has established a bridge of communication between the skeletal system and the immune system. Exploring the effects of pathogens, skeletal systems, immune systems, and antibacterials on bone repair in infectious conditions can help improve the treatment of these diseases.


Subject(s)
Anti-Bacterial Agents/administration & dosage , Bone and Bones/metabolism , Cellular Microenvironment , Humans , Immune System/immunology , Lymphocyte Subsets/immunology , Osteitis/microbiology , Osteoblasts/physiology , Osteoclasts/physiology , Staphylococcal Infections
6.
J. appl. oral sci ; 27: e20180596, 2019. graf
Article in English | LILACS, BBO | ID: biblio-1019968

ABSTRACT

Abstract Bone development and healing processes involve a complex cascade of biological events requiring well-orchestrated synergism with bone cells, growth factors, and other trophic signaling molecules and cellular structures. Beyond health processes, MMPs play several key roles in the installation of heart and blood vessel related diseases and cancer, ranging from accelerating metastatic cells to ectopic vascular mineralization by smooth muscle cells in complementary manner. The tissue inhibitors of MMPs (TIMPs) have an important role in controlling proteolysis. Paired with the post-transcriptional efficiency of specific miRNAs, they modulate MMP performance. If druggable, these molecules are suggested to be a platform for development of "smart" medications and further clinical trials. Thus, considering the pleiotropic effect of MMPs on mammals, the purpose of this review is to update the role of those multifaceted proteases in mineralized tissues in health, such as bone, and pathophysiological disorders, such as ectopic vascular calcification and cancer.


Subject(s)
Humans , Bone Remodeling/physiology , Matrix Metalloproteinases/physiology , Extracellular Matrix/physiology , Osteoblasts/physiology , Bone Diseases/physiopathology , Bone Diseases/metabolism , Disease Progression , Tissue Inhibitor of Metalloproteinases/physiology , Vascular Calcification/physiopathology , Vascular Calcification/metabolism , Matrix Metalloproteinase Inhibitors/therapeutic use , Neoplasms/physiopathology , Neoplasms/metabolism
7.
Braz. oral res. (Online) ; 32: e85, 2018. tab, graf
Article in English | LILACS | ID: biblio-952161

ABSTRACT

Abstract This study aimed to investigate the effects of different doses of systemic melatonin application on new bone formation during mandibular distraction osteogenesis (DO) in rats. Mandibular DO was performed on 30 adult female Sprague-Dawley rats, which were randomly divided into three groups: control group (CNT), melatonin dose 1 (MLT-D1), and melatonin dose 2 (MLT-D2). A five-day latent waiting period and a ten-day distraction phase followed the surgery. After the surgery, rats from the MLT-D1 and MLT-D2 groups received 25 and 50 mg/kg melatonin, respectively, at 7, 14, 21, 28, and 35 days. The animals were euthanised 28 days after distraction, i.e. at 43 days after surgery. Histological and histomorphometric analyses revealed that the distracted bone area was completely filled with new bone formation in all three groups. The MLT-D2 group exhibited the most new bone formation, followed by MLT-D1 and CNT. The melatonin groups had more osteoclasts than the CNT (p < 0.05). The number of osteoblasts was higher in the melatonin groups than in the CNT group, and the MLT-D2 had more osteoclasts than the MLT-D1 group (p < 0.05). Finally, the osteopontin (OPN) and vascular endothelial growth factor (VEGF) levels were higher in the melatonin groups than in the CNT group, and the MLT-D2 had higher OPN and VEGF levels than the MLT-D1 (p < 0.05). This study suggests that systemic melatonin application could increase new bone formation in DO.


Subject(s)
Animals , Female , Osteogenesis/drug effects , Bone Regeneration/drug effects , Osteogenesis, Distraction/methods , Melatonin/administration & dosage , Antioxidants/administration & dosage , Osteoblasts/physiology , Osteoclasts/physiology , Osteogenesis/physiology , Bone Regeneration/physiology , Immunohistochemistry , Random Allocation , Reproducibility of Results , Treatment Outcome , Rats, Sprague-Dawley , Vascular Endothelial Growth Factor A/analysis , Osteopontin/analysis , Mandible/surgery , Mandible/drug effects , Mandible/physiology , Mandible/pathology
8.
Braz. j. med. biol. res ; 51(12): e7574, 2018. graf
Article in English | LILACS | ID: biblio-974257

ABSTRACT

Bone fracture is a common medical condition, which may occur due to traumatic injury or disease-related conditions. Evidence suggests that microRNAs (miRNAs) can regulate osteoblast differentiation and function. In this study, we explored the effects and mechanism of miR-221 on the growth and migration of osteoblasts using MC3T3-E1 cells. The expression levels of miR-221 in the different groups were measured by qRT-PCR. Then, miR-221 mimic and inhibitor were transfected into MC3T3-E1 cells, and cell viability and migration were measured using the CCK-8 assay and the Transwell migration assay. Additionally, the expression levels of differentiation-related factors (Runx2 and Ocn) and ZFPM2 were measured by qRT-PCR. Western blot was used to measure the expression of cell cycle-related proteins, epithelial-mesenchymal transition (EMT)-related proteins, ZFPM2, and Wnt/Notch, and Smad signaling pathway proteins. miR-221 was significantly up-regulated in the patients with lumbar compression fracture (LCM) and trochanteric fracture (TF). miR-221 promoted ALP, Runx2, and OPN expressions in MC3T3-E1 cells. miR-221 overexpression significantly increased cell proliferation, migration, differentiation, and matrix mineralization, whereas suppression of miR-221 reversed these effects. Additionally, the results displayed that ZFPM2 was a direct target gene of miR-221, and overexpression of ZFPM2 reversed the promoting effects of miR-221 overexpression on osteoblasts. Mechanistic study revealed that overexpression of miR-221 inactivated the Wnt/Notch and Smad signaling pathways by regulating ZFPM2 expression. We drew the conclusions that miR-221 overexpression promoted osteoblast proliferation, migration, and differentiation by regulation of ZFPM2 expression and deactivating the Wnt/Notch and Smad signaling pathways.


Subject(s)
Humans , Animals , Rabbits , Cell Differentiation/physiology , Cell Movement/physiology , MicroRNAs/physiology , Cell Proliferation/physiology , DNA-Binding Proteins/physiology , Fractures, Bone/blood , Osteoblasts/physiology , Reference Values , Transcription Factors/blood , Cell Survival/physiology , Blotting, Western , Analysis of Variance , 3T3 Cells , MicroRNAs/blood , DNA-Binding Proteins/blood
9.
Actual. osteol ; 13(1): 28-36, Ene - Abr. 2017. tab
Article in Spanish | LILACS | ID: biblio-1118788

ABSTRACT

El pico de masa ósea (PMO) se alcanza entre los 20 y 35 años, pero la aposición ósea continúa hasta alcanzar el pico de fortaleza ósea (PFO). Se crea así una ventana entre ambos picos que podría ser evaluada mediante marcadores bioquímicos de recambio óseo, ya que durante dicho período la densidad mineral permanece constante. El objetivo fue determinar el final de la aposición ósea mediante marcadores bioquímicos óseos. Se evaluaron por décadas entre 20 y 49 años de edad 139 sujetos sanos de ambos sexos (69 hombres y 70 mujeres), determinando fosfatasa alcalina ósea (FAO), osteocalcina (OC), propéptido amino terminal del colágeno tipo 1 (P1NP) y telopéptido C-terminal del colágeno tipo 1 (CTX). Los marcadores correlacionan negativamente con la edad (OC: r= -0,3; p<0,01; P1NP: r= -0,4; p< 0,01 y CTX: r= -0,4; p<0,01), exceptuando FAO. En hombres de 20-29 años, P1NP y el CTX fueron significativamente mayores vs. 30-39 años (p<0,05 y p<0,001, respectivamente), y entre 30-39 años vs. de 40-49 años en P1NP y CTX (p<0,05; p<0,001, respectivamente). En mujeres de 20-29 años, P1NP y CTX fueron significativamente mayores vs. 30-39 años (p<0,0001 y p<0,01, respectivamente). Conclusión: los marcadores de remodelado óseo más sensibles y específicos permitirían determinar bioquímicamente el fin de la aposición ósea que se produce entre el PMO y el PFO. Si bien es necesario ampliar el número de sujetos evaluados, los datos que surgen de la presente investigación sentarían las bases para futuros estudios epidemiológicos referidos al fin de la aposición ósea. (AU)


Peak bone mass is achieved between 20-35 years; however bone apposition continues to reach an optimal skeleton strength. The window between peak bone mass and peak bone apposition may be evaluated by biochemical bone turnover markers. The objective of this study was to determine the end of bone apposition through biochemical bone markers in both sexes. A total of 139 subjects (69 men and 70 women) were divided by decades between 20 and 49 years of age. Bone alkaline phosphatase (BAL), osteocalcin (OC), type I collagen propeptide (P1NP) and type I collagen C-terminal telopeptide (CTX) were evaluated. Except BAL, the other bone markers negatively correlated with the age [OC (r= -0.3; p<0.01); P1NP (r= -0.4; p<0.01) and CTX (r= -0.4; p<0.01)]. Regarding men aged 20 to 29 years, P1NP and CTX were significantly higher vs. 30-39 years (p<0.05 y p<0.001, respectively) and. vs. 40-49 years (p<0.05; p<0.001, respectively). In women, the results were similar. Regarding 20-29 years, P1NP and CTX were higher vs. 30-39 years (p<0.001 y p<0.01, respectively). Bone remodeling rate decreases after the third decade, suggesting the end of the apposition period of peak bone mass. Conclusion: The most specific and sensitive bone markers would biochemically determine the end of bone apposition that extends between the peak of bone mass and the peak of bone strength. Although it is necessary to increase the number of subjects evaluated, the data that emerge from the present study would establish the bases for future epidemiological studies referring to the end of bone apposition. (AU)


Subject(s)
Humans , Male , Female , Adult , Middle Aged , Young Adult , Bone Resorption/physiopathology , Biomarkers , Osteoblasts/physiology , Osteoclasts/physiology , Osteogenesis/physiology , Bone and Bones/metabolism , Bone Density/physiology , Osteocalcin/blood , Calcium/blood , Age Factors , Bone Remodeling/physiology , Creatinine/blood , Collagen Type I/biosynthesis , Collagen Type I/blood , Densitometry , Alkaline Phosphatase/blood , Osteoporotic Fractures/prevention & control
10.
Bauru; s.n; 2017. 125 p. graf, ilus, tab.
Thesis in Portuguese | LILACS, BBO | ID: biblio-885135

ABSTRACT

Os leucotrienos (LTs) são mediadores inflamatórios derivados da via 5- lipoxigenase (5-LO), com contribuição relevante na reabsorção óssea. Neste estudo investigamos o papel dos LTs na diferenciação osteogênica e o seu impacto na osteoclatogênese. Assim, foi avaliado o perfil ósseo dos camundongos 129/Sv (WT) e 5-LO Knockout (5-LO KO) por meio de microtomografia computadorizada, evidenciando maior densidade óssea vertebral e trabéculas mais espessas em machos 5-LO KO. Após isso, osteoblastos primários (OBL) foram isolados e cultivados para determinar a atividade de fosfatase alcalina (ALP) e o potencial de mineralização. Resultados mostraram que OBL KO possui maior atividade de ALP e mineralização, em todos os períodos quando comparados com WT. Em adição, o tratamento com os LTs B4 e D4 inibiu a deposição de cálcio. Os inibidores da síntese de LTs e os antagonistas do BLT1/2 foram efetivos em recuperar a formação dos nódulos mineralizados. A cinética do Alox5 apresentou um aumento da expressão nos períodos de maior diferenciação celular em OBL WT. Além disso, a expressão de OCN, MMPs 2 e 9 e RANKL foram aumentadas em células 5-LO KO em quase todos os períodos avaliados. Em geral, o estímulo com LTs, seus inibidores e antagonistas diminuiu a expressão de Sp7, Col1a1, Opg e MMP-9 e aumentou RANKL em células KO. A sinalização por meio de segundos mensageiros também foi avaliada. Células 5-LO KO apresentam menor concentração de cálcio intracelular (Ca2+i) em relação ao WT. No período de 14 dias, o estímulo com LTD4 inibiu a liberação Ca2+i independente da linhagem, em relação ao controle. Os níveis de cAMP foram menores em OBL 5- LO KO, em todos os grupos tratados ou controle. LTD4 diminuiu a concentração de cAMP, mas não LTB4, em OBL 5-LO KO. O estudo também quantificou a produção de LTB4 e outros eicosanoides em osteoblastos mostrando a sua capacidade de síntese. A análise proteômica revelou 89 proteínas com expressão diminuída em OBL 5-LO KO, de um total de 154, sendo a maioria relacionada ao citoesqueleto e ao metabolismo energético. Também foram identificadas 59 proteínas exclusivas em OBL 5-LO KO e 06 unicamente expressas em células WT, revelando as diferenças intrínsecas de cada animal. O perfil osteoclastogênico de camundongos WT vs. 5-LO KO mostrou diferenças significativas na análise fenotípica, TRAP e na expressão gênica de células derivadas da linhagem monocítica-macrofágica. Após o estímulo com M-CSF e RANKL, as células WT apresentaram osteoclastos gigantes multinucleados, porém, células 5-LO KO apresentaram uma população de células com formas e tamanhos variáveis, e menor grau de maturação. Em adição, os LTsexógenos não modularam a atividade da TRAP. O meio condicionado proveniente dos OBL WT e KO, retardaram o processo de formação dos osteoclastos. A análise da expressão gênica em osteoclastos mostrou diminuição da expressão de Alox5, Il- 1b, Il-6 e TNFa em células 5-LO KO. BLT1/2, CysLt1 e os marcadores da diferenciação Acp5, Ctsk e Nfact1 não apresentaram diferenças entre os animais. Em adição, o LTB4 diminuiu a expressão do Alox5 e a Il-1b foi aumentada em osteoclastos WT. Assim, os resultados demonstram que os LTs são capazes de modular o metabolismo ósseo, e a ausência do gene da 5-LO está relacionada ao maior perfil osteogênico.(AU)


Leukotrienes (LTs) are inflammatory mediators derived from the 5-lipoxygenase (5-LO) pathway, with a relevant contribution in bone resorption. In this study we investigated the role of LTs in osteogenic differentiation and its impact on osteoclastogenesis.Thus, the bone profile of the 129/Sv (WT) and 5-LO Knockout mice (5-LO KO) was evaluated by computerized microtomography, showing higher vertebral bone density and thicker trabeculae in 5-LO KO males. After that, primary osteoblasts (OBL) were isolated and cultured to determine alkaline phosphatase activity (ALP) and mineralization potential. Results showed that OBL KO has higher ALP activity and mineralization, in all periods when compared with WT. In addition, the treatment with LTB4 and LTD4 inhibited calcium deposition. Inhibitors of LT synthesis and BLT1/2 antagonists were effective to recover the mineralized nodules formation. The kinetics of Alox5 showed an increase in expression during cellular differentiation period in WT OBL. In addition, expression of OCN, MMPs 2 and 9 and RANKL were increased in 5- LO KO cells in almost all evaluated periods. In general, the stimulation with LTs, their inhibitors and antagonists decreased the expression of Sp7, Col1a1, Opg and MMP- 9. But it increased the RANKL expression in KO cells. The second messengers signaling was also evaluated. 5-LO KO cells showed lower concentration levels of intracellular calcium (Ca2+ i) when compared to WT cells. In the 14-day period, the LTD4 treatment inhibited the Ca2+i independent of the murine lineage, relative to the control. cAMP levels were lower in OBL 5-LO KO, in all treated or control groups. LTD4 decreased the concentration of cAMP, but not LTB4, in KO cells. The study also quantified the production of LTB4 and other eicosanoids in osteoblasts showing their ability to synthesize those metabolites. The proteomic analysis revealed 89 downregulated proteins in OBL KO, out of a total of 154, most of them related to cytoskeleton and energy metabolism. Also 59 identified proteins were unique in OBL 5-LO KO and 06 exclusively expressed in WT cells, revealing the intrinsic differences of each strain. The osteoclastogenic profile of WT vs. 5-LO KO showed significant differences in phenotypic analysis, TRAP and in the gene expression of cells derived from the monocyte-macrophage-lineage. After M-CSF and RANKL stimulation, WT cells showed multinucleated giant osteoclasts. However, 5-LO KO cells presented a population of cells with variable shapes and sizes, and a lower maturation stage. In addition, exogenous LTs did not modulate TRAP activity. The conditioned medium from OBL WT and 5-LO KO delayed the formation process of osteoclasts. Gene expression analysis in osteoclasts showed decreased expression of Alox 5, Il-1b, Il-6 and TNFα in 5-LO KO cells. BLT1/2, CysLt1 and the osteoclast differentiation markers Acp5, Ctsk and Nfact1 showed no differences between the strains. In addition, LTB4 decreased the expression of Alox5, and IL-1b was increased in WT osteoclasts. Thus, the results demonstrate that the LTs are able to modulate the bone metabolism, and the absence of the 5-LO gene is related to the greater osteogenic profile.(AU)


Subject(s)
Animals , Male , Female , Mice , Leukotrienes/pharmacology , Osteoblasts/drug effects , Osteogenesis/drug effects , Osteogenesis/physiology , 5-Lipoxygenase-Activating Proteins/analysis , Bone Density , Gene Expression , Osteoblasts/physiology , Proteomics , RANK Ligand/analysis , Real-Time Polymerase Chain Reaction , Reproducibility of Results , Time Factors , X-Ray Microtomography
11.
J. appl. oral sci ; 24(4): 376-382, July-Aug. 2016. graf
Article in English | LILACS, BBO | ID: lil-792596

ABSTRACT

ABSTRACT Aging negatively affects bone/titanium implant interactions. Our hypothesis is that the unbalance between osteogenesis and adipogenesis induced by aging may be involved in this phenomenon. Objective We investigated the osteoblast and adipocyte differentiation of mesenchymal stem cells (MSCs) from young and aged rats cultured on Ti. Material and Methods Bone marrow MSCs derived from 1-month and 21-month rats were cultured on Ti discs under osteogenic conditions for periods of up to 21 days and osteoblast and adipocyte markers were evaluated. Results Cell proliferation, alkaline phosphatase (ALP) activity, extracellular matrix mineralization and gene expression of RUNX2, osterix, ALP, bone sialoprotein, osteopontin, and osteocalcin were reduced in cultures of 21-month rats compared with 1-month rats grown on Ti. Gene expression of PPAR-γ , adipocyte protein 2, and resistin and lipid accumulation were increased in cultures of 21-month rats compared with 1-month rats grown on the same conditions. Conclusions These results indicate that the lower osteogenic potential of MSCs derived from aged rats compared with young rats goes along with the higher adipogenic potential in cultures grown on Ti surface. This unbalance between osteoblast and adipocyte differentiation should be considered in dental implant therapy to the elderly population.


Subject(s)
Animals , Female , Rats , Osteoblasts/physiology , Titanium/chemistry , Aging/physiology , Dental Implants , Adipogenesis/physiology , Mesenchymal Stem Cells/physiology , Osteogenesis/physiology , Surface Properties , Gene Expression , Cells, Cultured , Age Factors , Cell Proliferation/physiology , Alkaline Phosphatase/analysis , Real-Time Polymerase Chain Reaction , Lipids/analysis
12.
Femina ; 43(6): 241-244, nov.-dez. 2015.
Article in Portuguese | LILACS | ID: lil-771221

ABSTRACT

O envelhecimento do esqueleto está associado a fatores intrínsecos e extrínsecos. Foi realizada uma pesquisa nas bases de dados e os artigos considerados de interesse foram aqueles publicados nos últimos 10 anos. O objetivo deste estudo é compreender a natureza das alterações morfológicas do osso e sua distribuição na massa óssea que determinam os fatores de risco e as características clínicas da osteoporose, procurando identificar em que circunstância a remodelação não consegue acompanhar a velocidade da reabsorção, deixando o osso frágil. As características da massa óssea são geneticamente programadas. Cabe ao profissional de saúde considerar o risco individualizado identificando em que momento a destruição supera a reconstrução, e quais fatores intrínsecos e extrínsecos modificam o esqueleto. O entendimento da fisiopatologia da osteoporose é matéria ímpar para a boa condução da doença do ponto de vista do profissional da saúde e da família, que necessita de envolvimento relevante e profundo.(AU)


The skeletal aging is associated with intrinsic and extrinsic factors. A survey was conducted on the basis of data and articles of interest were those published in the last 10 years. The objective of this study is to understand the nature of the morphological changes of the bone and its distribution in bone mass that determine the risk factors and clinical features of osteoporosis, trying to identify the circumstances in which remodeling cannot keep up the speed of resorption, leaving the bone fragile. The characteristics of bone mass is genetically programmed. The health professional must consider the individual risk and identify at what time the destruction overcomes reconstruction, as well as intrinsic and extrinsic factors that modify the skeleton. The understanding of the pathophysiology of osteoporosis is important for the proper disease conduct from the health professional?s point of view and the family, which needs deep and relevant involvement.(AU)


Subject(s)
Humans , Osteoporosis/physiopathology , Osteoporosis/epidemiology , Bone and Bones/anatomy & histology , Bone Density/physiology , Osteoblasts/physiology , Osteoclasts/physiology , Osteoporosis/prevention & control , Risk Factors , Databases, Bibliographic
13.
Acta cir. bras ; 30(2): 120-126, 02/2015. tab, graf
Article in English | LILACS | ID: lil-741028

ABSTRACT

PURPOSE: To evaluate the effects of copaiba oil on jaw defects repair in Wistar rats treated with bioglass or adipose tissue. METHODS: A jaw defect was randomly created in forty-two rats and filled with bioglass or adipose tissue. The two groups (Gbio and Gcell) were subdivided in three subgroups with seven animals each according to gavage administration: control (distillated water), oil (copaiba oil) and melox (meloxicam). Euthanasia was performed after forty post-operative days. The bone formation was analyzed regarding the histological aspects. RESULTS: The osteoclasts activity was observed only in four subgroups (p=0.78). Regarding the osteoblasts presence, it was very similar between the subgroups, the difference was due to Gcell-melox (p=0.009) that presented less osteoblastic activity. The inflammatory cells were more evident in Gcell-melox subgroup, however, there was no difference in comparison with the other subgroups (p=0.52). Bone formation was observed in all subgroups, just two animals showed no bone formation even after 40 days. More than 50% of bone matrix mineralization was observed in 56% (23 animals) of the analyzed areas. The bone matrix mineralization was not different between subgroups (p=0.60). CONCLUSIONS: The subgroups that received copaiba oil showed bone repair, although not statistically significant in comparison to subgroups treated whit meloxicam or controls. Copaiba oil administered by gavage had no effect on bone repair in this experimental model. .


Subject(s)
Animals , Male , Bone Regeneration/drug effects , Fabaceae/chemistry , Jaw/drug effects , Osteogenesis/drug effects , Plant Oils/pharmacology , Adipose Tissue/transplantation , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Bone Substitutes/therapeutic use , Ceramics/therapeutic use , Disease Models, Animal , Jaw Abnormalities/drug therapy , Jaw Abnormalities/physiopathology , Jaw/physiopathology , Osteoblasts/drug effects , Osteoblasts/physiology , Osteoclasts/drug effects , Osteoclasts/physiology , Rats, Wistar , Reproducibility of Results , Time Factors , Treatment Outcome , Thiazines/pharmacology , Thiazoles/pharmacology , Wound Healing/drug effects
14.
Biol. Res ; 48: 1-7, 2015. ilus
Article in English | LILACS | ID: biblio-950826

ABSTRACT

Bone is a unique tissue which could regenerate completely after injury rather than heal itself with a scar. Compared with other tissues the difference is that, during bone repairing and regeneration, after the inflammatory phase the mesenchymal stem cells (MSCs) are recruited to the injury site and differentiate into either chondroblasts or osteoblasts precursors, leading to bone repairing and regeneration. Besides these two precursors, the MSCs can also differentiate into adipocyte precursors, skeletal muscle precursors and some other mesodermal cells. With this multiline-age potentiality, the MSCs are probably used to cure bone injury and other woundings in the near future. Here we will introduce the recent developments in understanding the mechanism of MSCs action in bone regeneration and repairing.


Subject(s)
Humans , Animals , Osteogenesis/physiology , Bone Regeneration/physiology , Cell Differentiation/physiology , Chondrogenesis/physiology , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/physiology , Osteoblasts/physiology , Chondrocytes/physiology
15.
Biol. Res ; 48: 1-8, 2015. graf, tab
Article in English | LILACS | ID: biblio-950789

ABSTRACT

BACKGROUND: Mechanical strain plays a great role in growth and differentiation of osteoblast. A previous study indicated that integrin-ß (ß1, ß5) mediated osteoblast proliferation promoted by mechanical tensile strain. However, the involvement of integrin-ß; in osteoblastic differentiation and extracellular matrix (ECM) formation induced by mechanical tensile strain, remains unclear. RESULTS: After transfection with integrin-ß1 siRNA or integrin-ß5 siRNA, mouse MC3T3-E1 preosteoblasts were cultured in cell culture dishes and stimulated with mechanical tensile strain of 2500 microstrain (µÎµ) at 0.5 Hz applied once a day for 1 h over 3 or 5 consecutive days. The cyclic tensile strain promoted osteoblastic differentiation of MC3T3-E1 cells. Transfection with integrin-ß1 siRNA attenuated the osteoblastic diffenentiation induced by the tensile strain. By contrast, transfection with integrin-ß5 siRNA had little effect on the osteoblastic differentiation induced by thestrain. At thesametime, theresultofECM formation promoted by the strain, was similar to the osteoblastic differentiation. CONCLUSION: Integrin-ß1 mediates osteoblast differentiation and osteoblastic ECM formation promoted by cyclic tensile strain, and integrin-ß5 is not involved in the osteoblasts response to the tensile strain.


Subject(s)
Animals , Mice , Osteoblasts/physiology , Tensile Strength/physiology , Cell Differentiation/physiology , Integrin beta1/physiology , Integrin beta Chains/physiology , Extracellular Matrix/physiology , Stress, Mechanical , Transfection , Cell Line , Blotting, Western , RNA, Small Interfering , Cell Proliferation/physiology , Real-Time Polymerase Chain Reaction
16.
Recife; s.n; 2015. 94 p. ilus, graf, tab.
Thesis in Portuguese | LILACS | ID: biblio-871418

ABSTRACT

O titânio e suas ligas são os materiais mais comumente utilizados na substituição de tecidos duros por possuírem resistência mecânica, biocompatibilidade, resistência à corrosão e fácil manipulação. Embora o titânio possua várias vantagens sobre outros biomateriais, seu uso em longo prazo pode ocasionar problemas de rejeição. A modificação da superfície do titânio a fim de criar microrrugosidades é uma estratégia efetiva para melhorar a adesão e proliferação celular sobre implantes. Quando um implante danifica ou invade as barreiras epitelial e das mucosas, pode servir como reservatório para microrganismos e desta forma predispor à infecção. Neste sentido, o objetivo deste trabalho foi modificar a superfície do titânio, utilizando nanopartículas de prata (Ag) e lectina, a fim de melhorar a sua biocompatibilidade e conferir propriedades antimicrobianas a este material. O racional por trás destas mudanças é que a criação de uma topografia em nanoescala pode contribuir para mimetizar o ambiente celular melhorando a osseointegração e diminuindo o risco de infecção. Em nosso estudo, nanotubos de dióxido de titânio (NTs-TiO2) com estrutura bem distribuída e organizada, com diâmetro em torno de 70-80nm, foram sintetizados por anodização eletroquímica e decorados com nanopartículas de Ag usando a técnica de layer-by-layer (LbL), enquanto a lectina do peixe Oreochromis niloticus (OniL) foi incorporada aos NTs-TiO2 por spin coating. Estas amostras foram caracterizadas e avaliadas quanto a sua citotoxidade, adesão celular, potencial osteogênico e atividade bactericida. Nossos resultados mostraram que tanto as nanopartículas de Ag, como a Onil foram incorporadas com sucesso à superfície dos NTs-TiO2. Entretanto nossas preparações de LbL não foram capazes de melhorar a biocompatibilidade ou inibir o crescimento de bactérias nos NTs-TiO2. Por outro lado, a funcionalização dos NTs-TiO2 com a OniL induziu eficientemente a adesão e proliferação dos osteoblastos. Nossos resultados apontam para o uso da lectina OniL para melhorar a qualidade dos implantes de NT-TiO2 existentes.


Subject(s)
Humans , Animals , Anti-Bacterial Agents/chemistry , Lectins , Coated Materials, Biocompatible/chemistry , Coated Materials, Biocompatible/toxicity , Nanotubes , Metal Nanoparticles , Silver , Titanium , Anti-Bacterial Agents/toxicity , Cell Adhesion , Cells, Cultured , Candida albicans , Escherichia coli , Materials Testing , Coated Materials, Biocompatible/pharmacology , Osteoblasts/cytology , Osteoblasts/physiology , Staphylococcus aureus
17.
J. appl. oral sci ; 22(6): 541-553, Nov-Dec/2014. graf
Article in English | LILACS, BBO | ID: lil-732593

ABSTRACT

Objective The aim of this paper was to evaluate the repair of onlay autogenous bone grafts covered or not covered by an expanded polytetrafluoroethylene (e-PTFE) membrane using immunohistochemistry in rats with induced estrogen deficiency. Material and Methods Eighty female rats were randomly divided into two groups: ovariectomized (OVX) and with a simulation of the surgical procedure (SHAM). Each of these groups was again divided into groups with either placement of an autogenous bone graft alone (BG) or an autogenous bone graft associated with an e-PTFE membrane (BGM). Animals were euthanized on days 0, 7, 21, 45, and 60. The specimens were subjected to immunohistochemistry for bone sialoprotein (BSP), osteonectin (ONC), and osteocalcin (OCC). Results All groups (OVX+BG, OVX+BMG, SHAM+BG, and SHAM+BMG) showed greater bone formation, observed between 7 and 21 days, when BSP and ONC staining were more intense. At the 45-day, the bone graft showed direct bonding to the recipient bed in all specimens. The ONC and OCC showed more expressed in granulation tissue, in the membrane groups, independently of estrogen deficiency. Conclusions The expression of bone forming markers was not negatively influenced by estrogen deficiency. However, the markers could be influenced by the presence of the e-PTFE membrane. .


Subject(s)
Animals , Female , Bone Regeneration/physiology , Bone Transplantation/methods , Guided Tissue Regeneration/methods , Polytetrafluoroethylene/therapeutic use , Biomarkers/analysis , Estrogens/deficiency , Immunohistochemistry , Integrin-Binding Sialoprotein/analysis , Mandible/surgery , Osteoblasts/physiology , Osteocalcin/analysis , Osteonectin/analysis , Osteoporosis/physiopathology , Ovariectomy , Random Allocation , Rats, Wistar , Reproducibility of Results , Time Factors , Treatment Outcome
18.
Dental press j. orthod. (Impr.) ; 19(3): 20-23, May-Jun/2014. graf
Article in English | LILACS | ID: lil-723153

ABSTRACT

The functional demand imposed on bone promotes changes in the spatial properties of osteocytes as well as in their extensions uniformly distributed throughout the mineralized surface. Once spatial deformation is established, osteocytes create the need for structural adaptations that result in bone formation and resorption that happen to meet the functional demands. The endosteum and the periosteum are the effectors responsible for stimulating adaptive osteocytes in the inner and outer surfaces.Changes in shape, volume and position of the jaws as a result of skeletal correction of the maxilla and mandible require anchorage to allow bone remodeling to redefine morphology, esthetics and function as a result of spatial deformation conducted by orthodontic appliances. Examining the degree of changes in shape, volume and structural relationship of areas where mini-implants and miniplates are placed allows us to classify mini-implants as devices of subabsolute anchorage and miniplates as devices of absolute anchorage.


Uma demanda funcional sobre o osso promove alterações na forma espacial da rede de osteócitos e seus prolongamentos, distribuídos uniformemente na estrutura mineralizada. A partir da deformação espacial captada, os osteócitos comandam a necessidade de adaptações estruturais, formando osso em novas áreas e reabsorvendo em outras, para que sejam atendidas as demandas funcionais. O endósteo e o periósteo são os verdadeiros efetores desses estímulos osteocíticos adaptativos, nas superfícies internas e externas. As alterações de forma, volume e posição dos ossos maxilares, nas correções esqueléticas da maxila e mandíbula, requerem uma ancoragem para que a remodelação óssea redefina a morfologia, a estética e as funções, a partir de deformações espaciais dirigidas por aparelhos. Verificar o grau de alterações na forma, volume e relações estruturais das áreas onde se fixaram os mini-implantes e as miniplacas poderá levar à classificação dos mini-implantes como dispositivos de ancoragem subabsoluta e as miniplacas, como de ancoragem absoluta.


Subject(s)
Humans , Bone Plates , Dental Implants , Orthodontic Anchorage Procedures/instrumentation , Bone Matrix/physiology , Bone Remodeling/physiology , Bone Resorption/physiopathology , Miniaturization , Mandible/cytology , Maxilla/cytology , Mechanotransduction, Cellular/physiology , Orthodontic Appliance Design , Osteoblasts/physiology , Osteoclasts/physiology , Osteocytes/physiology , Osteogenesis/physiology , Periosteum/physiology , Tooth Movement Techniques/instrumentation
19.
Dental press j. orthod. (Impr.) ; 19(1): 5-7, Jan-Feb/2014.
Article in English | LILACS | ID: lil-709638

ABSTRACT

A common question about root resorption is raised in orthodontic practice: What is more important, the intensity of force or its distribution along the root, periodontal and alveolar structures? Diffuse distribution of forces applied to periodontal tissues during tooth movement tends not to promote neither extensive areas of cell matrix hyalinization nor significant death of cementoblasts that lead to root resorption. However, focal distribution or concentration of forces within a restricted area - as it occurs in tipping movements, even with forces of lower intensity - tend to induce extensive areas of hyalinization and focal death of cementoblasts, which is commonly associated with root resorption. In tipping movements, the apical regions tend to concentrate more forces in addition to wounding the cementoblasts due to the smaller dimension of their root structure as well as their cone shape. For this reason, there is an increase in root resorption. In the cervical region, on the other hand, the large area resulting from a large diameter and bone crown deflection tends to reduce the effects of forces, even when they are more concentrated, thus rarely inducing death of cementoblasts and root resorption.


Um questionamento comum sobre as reabsorções radiculares na prática ortodôntica: "O que é mais importante? A intensidade das forças aplicadas ou sua distribuição ao longo das estruturas radiculares, periodontais e alveolares?" A distribuição difusa das forças aplicadas sobre os tecidos periodontais durante o movimento dentário de corpo tende a não promover extensas áreas de hialinização da matriz extracelular, nem morte significativa de cementoblastos que levariam à reabsorção radicular. Porém, a distribuição focal ou concentração de forças - como nas inclinações, mesmo nas de menor intensidade - em uma área restrita tende a induzir áreas extensas de hialinização e morte focal de cementoblastos, associando-se mais comumente à reabsorção radicular. Nos movimentos de inclinação, as áreas apicais, por sua menor dimensão da estrutura radicular e sua forma cônica, tendem a concentrar mais ainda as forças e lesar cementoblastos, aumentando a frequência das reabsorções radiculares. Na região cervical, a maior área decorrente do maior diâmetro e a deflexão óssea da crista óssea tendem a reduzir os efeitos das forças, mesmo quando mais concentradas, muito raramente induzindo a morte de cementoblastos e reabsorções radiculares.


Subject(s)
Humans , Orthodontic Appliances , Root Resorption/etiology , Tooth Movement Techniques/instrumentation , Alveolar Process/pathology , Biomechanical Phenomena , Dental Cementum/pathology , Fibroblasts/physiology , Hyalin/physiology , Osteoblasts/physiology , Periodontal Ligament/pathology , Root Resorption/pathology , Stress, Mechanical , Tooth Apex/pathology , Tooth Cervix/pathology , Tooth Movement Techniques/adverse effects , Tooth Root/pathology
20.
Acta cir. bras ; 28(8): 574-581, Aug. 2013. ilus, tab
Article in English | LILACS | ID: lil-680611

ABSTRACT

PURPOSE:To investigate by histomorphometry the distraction osteogenesis by Ilizarov technique in dog radius with the use of autologous stem cells in regenerated bone. METHODS:Ten dogs (20 radiuses) underwent the osteotomy of 20% of extension of their radiuses, and osteogenic distraction using the Ilizarov technique after this procedure at rate of 1mm per day divided into 0.5mm every 12 hours. The elongation was performed until the regeneration reached 20% of the total length of the radius. The stem cells were isolated, concentrated and injected in the regenerated bone, when it reached 10% of the length of the entire radius. The regenerated bone was evaluated using histomorphometric analysis when the elongation was 20% the size of radius. RESULTS: The bone formation was evidenced by histomorphometric indices were significantly greater in the study group. In the histology evaluation the type of healing was mixed in 80% (intra membrane and endocondral) in both groups; the osteoblastic activity from moderate to intense was greater in the study group; and the space occupied by the newly-formed bone tissue was more evident in the study group. CONCLUSIONS:The histomorphometric indices in this study expressing the microarchitecture, trabecular thickness, trabecular spacing, number of trabecula and quantity of bone that was significant in the group study. These data suggest that the use of undifferentiated stem cells autologous bone marrow in the regenerate bone induces osteogenesis and bone quality.


Subject(s)
Animals , Dogs , Bone Marrow Transplantation/methods , Bone Regeneration/physiology , Ilizarov Technique , Radius/surgery , Stem Cell Transplantation/methods , Fracture Healing , Osteoblasts/physiology , Osteogenesis/physiology , Reproducibility of Results , Radius , Time Factors , Transplantation, Autologous , Treatment Outcome
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