Orientador: Marcelo Gonçalves / Banca: Mário Tanomaru Filho / Banca: Mariza Akemi Matsumoto / Resumo: A radiografia periapical convencional é o método mais utilizado na detecção e controle de lesões periapicais após o tratamento endodôntico. Atualmente, a tomografia computadorizada de feixe cônico (TCFC) tem sido amplamente utilizada, não apenas para uso clínico como também para fins de pesquisa. Diferentes metodologias têm sido descritas com o propósito de avaliar a instrumentação dos canais radiculares. Em associação aos avanços nos softwares de imagem, a TCFC tem se mostrado importante no desenvolvimento de métodos de avaliação, especialmente na área de Endodontia, como por exemplo, para avaliações do preparo do canal radicular e do reparo periapical após o tratamento endodôntico. No entanto, a fim de se obter métodos de avaliação comparativa mais criteriosos, e que possibilitem o uso da técnica de subtração digital (SD), torna-se importante a padronização das imagens. Na primeira parte deste estudo foi realizada a avaliação comparativa da mensuração da lesão periapical por dois métodos: a tomografia computadorizada com aquisição volumétrica (de feixe cônico) e a radiografia periapical digitalizada, nos períodos final do tratamento endodôntico (T0) e três meses de proservação (T1). Os dados obtidos para as mensurações radiográficas e tomográficas foram submetidas aos testes T Pareado e ANOVA, com nível de significância de 5%. Os resultados mostraram que as medidas obtidas nos métodos, radiográfico e tomográfico, foram semelhantes em ambos os períodos avaliados, demonstrando redução significativa da área de lesão aos três meses de proservação (p<0,05) e de forma semelhante nos dois métodos de avaliação (p>0,05). A partir dos resultados pode-se concluir que os métodos de avaliação por imagem, radiográfico e tomográfico, evidenciaram a regressão de lesões periapicais, três meses após o tratamento endodôntico... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Periapical conventional radiography is the most used method in detection and control of periapical lesions after endodontic treatment. Actually, cone beam computed tomography (CBCT) has been widely used, not only for clinical use as also for research ends. Different methods have been described with the proposal of evaluate root canal instrumentation. In association to image software development CBCT has revealed to be important in the evaluation methods development, especially in Endodontics, for example, in the evaluation of root canal preparation and in the evaluation of periapical repair after endodontic treatment. However, in order to obtain more criterious comparative evaluation methods, which enable the use of radiographic subtraction technique, images standardization becomes important. In the first part of this study, a comparative evaluation of periapical lesion measurement was realized by two methods: volumetric acquisition computed tomography (cone beam) and periapical digitalized radiography, in the periods at the end of endodontic treatment (T0) and at three months of follow up (T1). Data obtained were submitted to T and ANOVA tests, with 5% of significance. The results showed that the measurements obtained in radiographic and tomographic methods were similar in both of evaluated periods demonstrating significant decrease of lesion area after three months (p<0,05) and similarly in these two evaluation methods. From the results is concluded that radiographic and tomographic evaluation methods showed the regression of periapical lesions, at three months of follow up period (T1), providing similar measurements. In the following parts of this study, standardization techniques for images obtained from volumetric acquisition computed tomography or cone beam (CBCT) were proposed. Both the techniques used the Xoran software (Xoran Technologies - Ann Arbor - Michigan/USA)... (Complete abstract click electronic access below) / Mestre

A movimentação dentária induzida em ratos representa um bom modelo para estudar a aposição e reabsorção óssea induzidas na normalidade e nas doenças ósseas metabólicas, bem como nas avaliações quanto aos efeitos de medicamentos. Desta maneira, no primeiro capítulo estudaremos a influência do alendronato no percentual de reabsorções radiculares durante a movimentação dentária induzida, utilizando o modelo experimental em ratos em cortes transversais. O alendronato é um tipo de bisfosfonato, uma classe de drogas amplamente utilizada na medicina, no controle da osteopenia, prevenindo a osteoporose humana e na prevenção das fraturas em osteoporose pós-menopausal. O modelo experimental empregado nos trabalhos é o movimento de inclinação mesial do primeiro molar superior. Variações metodológicas são observadas neste modelo experimental em ratos, quanto aos períodos de movimentação e aos cortes empregados para a análise microscópica. Desta maneira, no segundo capítulo compararemos o percentual e a freqüência das reabsorções radiculares em cortes transversais e longitudinais, e sugeriremos o plano de corte ideal para o estudo da movimentação dentária induzida em ratos. A biologia da movimentação dentária induzida modifica-se por uma série de condicionantes, por exemplo, por diferentes períodos de observação e por planos dos cortes microscópicos Desta maneira, no terceiro capítulo avaliaremos os fenômenos teciduais e celulares da movimentação dentária induzida nos períodos de três, cinco, sete e nove dias de observação e nos planos dos cortes microscópicos transversais e longitudinais. / Induced tooth movement in rats is a good model to investigate the induction of bone resorption and apposition in normality and in metabolic bone diseases, as well as to evaluate the effects of drugs. Thus, the first chapter addresses the influence of alendronate on the percentage of root resorptions during induced tooth movement, using the experimental model of rats on transverse sections. Alendronate is a type of bisphosphonate, a class of drugs widely used in Medicine for osteopenia control, human osteoporosis prevention, as well as for fracture prevention in postmenopausal osteoporosis. Investigations employ the experimental model of mesial inclination of the maxillary first molar. Methodological variations are observed in this experimental model in rats concerning the periods of tooth movement and sections employed for microscopic analysis. Thus, on the second chapter, the percentage and frequency of root resorptions on transverse and longitudinal sections are compared, and the ideal direction of section for investigation of induced tooth movement in rats is suggested. The biology of induced tooth movement is changed by several factors, e.g. the different study periods and directions of microscopic sections. For this reason, the third chapter comprises evaluation of tissue and cellular phenomena of induced tooth movement at study periods of three, five, seven and nine days, on transverse and longitudinal sections.

Na gravidez, a deficiência de cálcio tem sido associada a complicações como pré-eclâmpsia, hiperparatireoidismo, osteoporose e desnutrição, o que aumenta a frequência de crianças pré-termo, de baixo peso e pequenas para a idade gestacional (PIG). Este estudo teve como objetivo avaliar o estado nutricional de cálcio em gestantes no terceiro trimestre gestacional, utilizando como parâmetros a ingestão dietética, o cálcio urinário e o telepeptídio carboxiterminal do colágeno (CTx) no plasma. Cinquenta e duas gestantes foram selecionadas no Serviço de Obstetrícia do HU-USP. As participantes responderam um registro alimentar (3 dias) e um recordatório de 24h. Para a análise dos alimentos consumidos foi utilizado o software Nutriquanti (GALANTE & COLLI, 2007). Verificou-se a distribuição normal da ingestão de cálcio e ajustaram-se os dados pela energia de acordo com o método do nutriente residual, posteriormente corrigidos pela variabilidade intrapessoal e interpessoal. Só uma gestante teve ingestão maior do que a AI (1.000 mg/d), sendo, portanto, a única que teve ingestão de Ca adequada, segundo a referência AI. Por outro lado, considerando o CTx (não aumentado em relação ao Intervalo de Referência), e considerando que 60% das gestantes apresentam hipercalciuria, supõe-se que o equilíbrio de Ca se deu pela absorção intestinal e a reabsorção renal e não pela reabsorção óssea, indicando ingestão de Ca adequada (612 ±187 mgCa/d). / During pregnancy, calcium deficiency has been associated with complications such as pre-eclampsia, hyperparathyroidism, osteoporosis and malnutrition, which increase the frequency of preterm babies, low-weighed and small for their gestational age (SGA). This study aimed to evaluate calcium nutritional status of pregnant women in the last third of pregnancy, using diet intake, urinary calcium and plasma colagen carboxy-terminus telepeptide (CTx) as parameters. Fifty-two pregnant women were selected in the Obstetrics Service of the University Hospital (HU-USP). The subjects completed a food-consumption record (3 days) e a 24-h record. For the consumed-food analysis, Nutriquanti software (GALANTE & COLLI, 2007) was used. A normal distribution of calcium intake was observed when the data were adjusted for energy according to the residual-nutrient method and corrected to consider intrapersonal and interpersonal variability afterwards. Only one pregnant woman showed a higher intake than the AI (1.000 mg/day), and therefore only this one is considered to present an adequate Ca intake when the reference is the AI. On the other hand, considering that CTx was not increased in relation to the Reference Interval and that 60% of the pregnant women presented hypercalciuria, we can say that Ca balance was due to intestinal absorption and renal resorption rather than bone resorption, thus indicating an adequate Ca intake (612 ±187 mgCa/day).

[Truncated abstract] Osteoclasts are multinucleated giant cells responsible for the resorption of the mineralized bone matrix during the process of bone remodelling. During activation towards bone resorption, polarization of the osteoclast results in the formation of a unique plasma membrane, the ruffled border, the actual resorptive organelle of the osteoclast. Through this domain protons are actively pumped into the resorption lacuna creating an acidic microenvironment that favours the dissolution of the mineralized bone matrix. The polarised secretion of protons is carried out by the action of the vacuolar-type (H+)-ATPase (V-ATPase), composed of functionally and structurally distinct subunits of the V1 and V0 domains. The general structure of the V-ATPase complex is highly conserved from yeast to mammals, however, multiple isoforms for specific V-ATPase subunits do exist exhibiting differential subcellular, cellular and tissue-specific localizations. This study focuses on the molecular identification and characterization of V-ATPase accessory subunit Ac45 and the d2 isoform of the V0 domain d subunit in osteoclasts. Using the techniques of cDNA Subtractive Hybridization and DNA Micro-Array analyses respectively, the accessory subunit Ac45 and the d2 isoform of the V0 domain d subunit were identified in RAW264.7-cells derived OcLs. ... Using web-based computational predictions, two possible transmembrane domains, an N-terminus 'signal anchor' sequence and a C-terminus dilysine- like endoplasmic reticulum (ER) retention signal were identified. By confocal microscopy, EYFP-tagged e was found to localize to the perinuclear region of transfected COS-7 cells in compartments representing the ER and Golgi apparatus with some localization in late endosomal/lysosomal-like vesicles. ER truncation of e did not alter its subcellular localization but exhibited significantly weaker association with Ac45 compared to the wild-type as depicted by BRET analyses. Association with the other V0 subunits remain unaffected. This may hint at a possibility that Ac45 may play a role in the masking of the ER signal of e following it's incorporation into the V0 domain. Although no solid evidence for a role in the assembly of the mammalian VATPase have been established, subunit e still represents a potential candidate whose role in the V-ATPase complex requires further investigation. Collectively, the data presented in this thesis has provided further insight into the composition of the osteoclast V-ATPase proton pump by: 1) identifying an accessory subunit, Ac45 which shows promise as a potential candidate for the regulation and/or targeting of the V-ATPase complex in osteoclasts and truncation of its targeting signal impairs osteoclastic bone resorption; 2) identification and preliminary characterization of the d2 isoform of the V0 domain d subunit whose exact role in the V-ATPase complex and in osteoclasts remains to be determined, although its has been implicated to be essential for osteoclastic function; and 3) Preliminary characterization of subunit-e, a potential assembly factor candidate for the mammalian V-ATPase V0 domain.

The calcitonin gene family of peptides consists of calcitonin (CT), two calcitonin gene related peptides (α-CGRP, β-CGRP), adrenomedullin (ADM), amylin (AMY), three calcitonin receptor activating peptides (CRSP1-3) and intermedin/adrenomedullin2 (IMD). These peptides bind to one of two G protein -coupled receptors, the calcitonin receptor (CTR) or the calcitonin receptor-like receptor (CRLR). The receptor specificity to different ligands is dependent on the formation of a complex with one of three receptor activity-modifying proteins (RAMP1-3). The aim of this study was to analyse effects of this family of peptides on the formation of osteoclasts and bone resorption, and the expression of the receptor components in bone cells. CT inhibited the formation of multinucleated osteoclasts in spleen cell cultures and in bone marrow macrophage cultures (BMM) without affecting a number of genes important for osteoclast differentiation, activity or fusion of osteoclast progenitor cells. All members of the CT family, except ADM, inhibited osteoclastogenesis in BMM. The inhibitory effect seemed to involve activation of both protein kinase A and the exchange protein directly activated by cyclic AMP (Epac) signalling. BMM expressed the CRLR, RAMP1-3 and the receptor component protein (RCP). AMY, ADM, CGRP and IMD, but not CRSP and CT, increased cyclic AMP (cAMP) levels in these cells, indicating the presence of functional receptors. Stimulation of BMM with RANKL gradually increased the levels of CTR mRNA as well as the capacity of the cells to respond to the stimulation by CRSP and CT. The response to stimulation of ADM was, on the contrary, decreased by RANKL. Stimulation of RANKL caused a transiently enhanced CRLR mRNA expression and transiently decreased RAMP1, but did not affect RAMP2, RAMP3, or RCP mRNA. However, RANKL did not affect protein levels of CRLR or RAMP1-3. CT, CGRP, AMY, ADM, IMD and CRSP all down regulated the CTR mRNA, but none of the peptides caused any effects on the expression of CRLR or any of the RAMPs. All members of the CT family, except ADM, rapidly and transiently, inhibited bone resorption in mouse calvarial bones. CT, CGRP, AMY and CRSP also significantly stimulated cAMP formation in the calvaria. cAMP analogues specifically stimulating the PKA or the Epac pathways did not cause inhibition of bone resorption in the calvaria. An unspecific cAMP analogue, stimulating both pathways did, however, cause inhibition. Analyses of an osteoblastic cell line, MC3T3-E1, showed that these cells express the mRNA for CRLR and all three RAMP proteins. In conclusion, the results of this thesis show that all peptides in CT family of peptides, except ADM, inhibit of bone resorption and osteoclast formation and that these effects involve the adenylate cyclase-cAMP pathway. Furthermore, expressions of CRLR and RAMP1-3 mRNA have been demonstrated on osteoclasts, as well as in an osteoblastic cell line.

Bone metabolism is regulated by endocrine and paracrine signalling molecules influencing bone cells in the continuously remodelling bone tissue. These molecules include a variety of osteotropic stimulatory and inhibitory cytokines. Degradation of alveolar bone in periodontal disease is believed to be a result of local release of such osteotropic cytokines, although the relative importance of particular cytokines and their cellular origin is currently unknown. The aim of the present project was to study if, and how, pro-inflammatory cytokines in the interleukin-6 (IL-6) family of cytokines, and anti-inflammatory IL-4 and IL-13 type of cytokines, can affect osteoclast differentiation and bone resorption. Additionally, the objective was to study if gingival fibroblasts may influence alveolar bone resorption through secretion of IL-6 type cytokine release and if the secretion is regulated by pro-inflammatory as well as anti-inflammatory mediators such as IL-4 and IL-13. IL-6 in combination with its soluble receptor (sIL-6R) was found to stimulate mouse calvarial bone resorption. Similarly, two other IL-6 family members, leukemia inhibitory factor (LIF) and oncostatin M (OSM) were found to stimulate bone resorption. The stimulatory effect on bone resorption induced by the three cytokines was associated with increased expression of receptor activator of NF- κB ligand (RANKL), a cytokine which is essential in osteoclast formation and activation through binding to receptor activator of NF- κB (RANK) on osteoclastic cells. The interaction between RANKL and RANK can be inhibited by binding of the decoy receptor osteoprotegerin (OPG) to RANKL, and the expression of OPG was also regulated by IL-6, LIF and OSM (Paper I). The two related cytokines IL-4 and IL-13 were found to inhibit osteoclastogenesis and mouse calvarial bone resorption by mechanisms involving a decreased RANKL/OPG ratio in osteoblasts and decreased RANK expression in osteoclastic cells. The results further demonstrated that IL-4 and IL-13 exert their effects on both osteoblasts and osteoclasts by a mechanism involving the transcription factor signal transducer and activator of transcription 6 (STAT6) (Paper II). Constitutional expression of IL-6, LIF and another member of the IL-6 family of cytokines, IL-11, was demonstrated in human gingival fibroblasts. IL-6 type cytokine expression levels were found to be enhanced by IL-1β and tumour necrosis factor-α (TNF-α) (Paper III), whereas IL-4 and IL-13 inhibited IL 11 and LIF release from gingival fibroblasts (Paper IV). In conclusion, IL 6 type cytokines were found to be stimulators and IL-4 and IL-13 inhibitors of bone resorption in vitro via mechanisms involving RANK/RANKL/OPG interactions. Additionally, gingival fibroblasts were able to secrete several cytokines in the IL-6 family. Secretion was further enhanced by pro-inflammatory mediators and inhibited by IL-4 and IL- 13. These findings support the view that resident cells may influence the pathogenesis of periodontal disease through osteotropic cytokine production.

Bone tissue is continuously degraded and rebuilt to respond to the needs of the body. Cells of the osteoblast lineage are responsible for the formation of bone, whereas the resorption of bone tissue is carried out by osteoclasts. To prevent imbalance between bone formation and resorption, these processes are delicately regulated by a complex network of both systemic factors and factors produced locally in the bone microenvironment, including members of the IL-6 family of cytokines. During the last decades, the presence of nerve fibers in skeletal tissue and presence of receptors for several neurotransmitters on both osteoblasts and osteoclasts, have suggested a possible role for neuropeptides in the regulation of skeletal metabolism. The overall aim of this study was to investigate the roles of cytokines in the IL-6 family and the neuropeptide VIP in regulation of osteotropic cytokine expression and bone metabolism in vitro. In Paper I, stimulation of bone resorption by the cytokine IL-6, in the presence of its soluble receptor sIL-6R, was demonstrated in mouse calvarial bones. OSM and LIF, other members of the IL-6 family of cytokines, were also shown to increase bone resorption. Furthermore, IL-6+sIL-6R, LIF, and OSM increased the expression of RANKL, which by binding to its receptor RANK functions as a crucial inducer of osteoclast formation and activation. In Paper II-IV, the effects of the neuropeptide VIP and related peptides on expression of osteotropic cytokines by osteoblasts and bone resorption in vitro have been studied. VIP and PACAP-38 both increased IL-6 production in osteoblasts in a time- and concentration-dependent manner. In contrast, no effect was seen with the related peptide secretin, indicating that the effects were mediated by the VPAC2 receptor. VIP and PACAP, in contrast to secretin, also induced IL-6 promoter activity in osteoblastic MC3T3-E1 cells transfected with an IL-6 promoter/luciferase construct. The effects of VIP on IL-6 were shown to be mediated by several intracellular pathways, including cAMP/PKA/CREB, AP-1, and C/EBP, but not NF-kB or the cAMP-activated Epac pathway. The release of IL-6 from osteoblasts was increased by several pro-inflammatory osteotropic cytokines, including interleukin-1b, an effect that was further potentiated by VIP, indicating a possible neuro-immunomodulatory interaction in the regulation of bone metabolism. VIP and PACAP-38 also increased the osteoblastic expression of RANKL and decreased the expression of OPG and M-CSF, factors crucial in regulation of differentiation and activation of osteoclasts. Although this indicated a possible bone resorptive effect, VIP was found to decrease osteoclast formation and bone resorption by directly targeting osteoclast progenitor cells through an inhibitory mechanism. In conclusion, the results in this thesis indicate that several cytokines in the IL-6 family stimulate bone resorption in calvarial bones in vitro, most likely through the RANKL-RANK interaction. Furthermore, expression of the osteotropic cytokine IL-6 in osteoblasts is stimulated by the neuropeptide VIP through VPAC2 receptors via several intracellular pathways, further strengthening the role of neuropeptides as local regulators of bone metabolism.

Rosiglitazone (RSG) is an insulin-sensitizing drug used to treat Type 2 Diabetes Mellitus (T2DM). Clinical trials show that women taking RSG experience more limb fractures than patients taking other T2DM drugs. The purpose of this study is to understand how RSG (3mg/kg/day and 10mg/kg/day) and the bisphosphonate alendronate (0.7mg/kg/week) alter bone quality in the male, female and female ovariectomized (OVX) Zucker fatty rat model over a 12 week period. Bone quality was evaluated by mechanical testing of cortical and trabecular bone. Microarchitecture, bone mineral density (BMD), cortical bone porosity, bone formation/resorption and mineralization were also measured. Female OVX RSG10mg/kg rats had significantly lower vertebral BMD and compromised trabecular architecture versus OVX controls. Increased cortical porosity and decreased mechanical properties occurred in these rats. ALN treatment prevented these negative effects in the OVX RSG model. Evidence of reduced bone formation and excess bone resorption was detected in female RSG-treated rats.

Rosiglitazone (RSG) is an insulin-sensitizing drug used to treat Type 2 Diabetes Mellitus (T2DM). Clinical trials show that women taking RSG experience more limb fractures than patients taking other T2DM drugs. The purpose of this study is to understand how RSG (3mg/kg/day and 10mg/kg/day) and the bisphosphonate alendronate (0.7mg/kg/week) alter bone quality in the male, female and female ovariectomized (OVX) Zucker fatty rat model over a 12 week period. Bone quality was evaluated by mechanical testing of cortical and trabecular bone. Microarchitecture, bone mineral density (BMD), cortical bone porosity, bone formation/resorption and mineralization were also measured. Female OVX RSG10mg/kg rats had significantly lower vertebral BMD and compromised trabecular architecture versus OVX controls. Increased cortical porosity and decreased mechanical properties occurred in these rats. ALN treatment prevented these negative effects in the OVX RSG model. Evidence of reduced bone formation and excess bone resorption was detected in female RSG-treated rats.

Patients with inflammatory or infectious conditions such as periodontitis, peri-implantitis, osteomyelitis, rheumatoid arthritis, septic arthritis and loosened joint prosthesis display varying severity of destruction in the adjacent bone tissue. Bone loss in inflammatory diseases is considered a consequence of cytokine induced RANKL and subsequent enhanced osteoclast formation. Hence, osteotropic cytokines and their receptors have been suggested to be important for the pathogenesis of inflammation-induced osteolysis. It is, here, suggested that bacterial components, so called “pathogen associated molecular patterns=PAMPs”, may also be involved. Varieties of cells express receptors for PAMPs, including Toll-like receptors (TLRs) which are the first line of defence in the innate immune system. LPS (lipopolysaccharide), fimbria and lipoproteins from pathogenic bacteria such as P. gingivalis, S. aureus are ligands for TLR2 and flagellin from pathogenic flagellated bacteria like S. typhimurium is a ligand for TLR5.   Since the susceptibility to, or the severity of inflammation-associated bone diseases are likely related to differences in the tissue response, and the mechanisms by which PAMPs interact with bone cells are not fully understood, we aimed to elucidate the importance of different TLRs for inflammation induced bone loss by conducting in vitro and in vivo investigations. Activation of TLR2 and TLR5 in organ cultured mouse parietal bones increased bone resorption in a time- and concentration-dependent manner by a process inhibited by OPG and bisphosphonate, showing the crucial role of RANKL-induced osteoclast formation. In addition, the number of osteoclasts, expression of osteoclastic genes and osteoclastogenic transcription factors were increased. In the bones and in osteoblasts isolated from the bones, TLR2 agonists increased the expression of RANKL without affecting OPG, while TLR5 activation resulted in enhanced RANKL and decreased OPG. Activation of both TLR2 and TLR5 stimulated the expression in both bones and osteoblasts of prostaglandins and pro-inflammatory cytokines, known to stimulate RANKL. By blocking the cytokines and prostaglandin, we showed that TLR2 and TLR5 induced bone resorption and RANKL expression are independent of these molecules. Activation of TLR2, but not TLR5, in mouse bone marrow macrophage cultures inhibited RANKL-induced osteoclast formation, an effect not observed in committed pre-osteoclasts. Local administration in vivo of TLR2 and TLR5 agonists on the top of mouse skull bones enhanced local and systemic osteoclast formation and bone resorption. Using knockout mice, we showed that the effects by LPS from P. gingivalis (used as TLR2 agonist) and flagellins (used as TLR5 agonists) are explicit for TLR2 and TLR5 ex vivo and in vivo, respectively. These data show that stimulation of TLR2 and TLR5 results in bone resorption in vitro and in vivo mediated by increased RANKL in osteoblasts and thus may be one mechanism for developing inflammatory bone loss. Interestingly, histological analyses of skull bones of mice treated locally with TLR2 and TLR5 agonists revealed that the bones not only reacted with locally increased osteoclastogenesis (osteoclast formation), but also with locally increased new bone formation. This was observed on both periosteal and endosteal sides of the bones, as well as in the bone marrow compartment. The formation of new bone was seen close to osteoclasts in some parts, but also in other areas, distant from these cells. The response was associated with active, cuboidal osteoblasts, extensive cell proliferation and increased expression of genes coding for bone matrix proteins and osteoblastic transcription factors. In conclusion, activation of TLR2 and TLR5 in osteoblasts results in bone loss associated with enhanced osteoclast formation and bone resorption, as well as with increased osteoblast differentiation and new bone formation, indicating that inflammation causes bone modeling. The data provide an explanation why LPS from P. gingivalis and flagellin from flagella-expressing bacteria can stimulate bone loss. Since TLR2 and TLR5 can be activated not only by bacterial components, but also by endogenous ligands produced in inflammatory processes, the data also contribute to the understanding of inflammation induced bone loss in autoimmune diseases. Hopefully, these findings will contribute to the development of treatment strategies for inflammation induced bone loss.