Dissertations / Theses on the topic 'Bone formation/resorption'

The bone remodelling process, performed by the Bone Multicellular Unit (BMU) is a key multi-hierarchically regulated process, which provides and supports various functionality of bone tissue. It is also plays a critical role in bone disorders, as well as bone tissue healing following damage. Improved modelling of bone turnover processes could play a significant role in helping to understand the underlying cause of bone disorders and thus develop more effective treatment methods. Moreover, despite extensive research in the field of bone tissue engineering, bonescaffold development is still very empirical. The development of improved methods of modelling the bone remodelling process should help to develop new implant designs which encourage rapid osteointegration. There are a number of limitations with respect to previous research in the field of mathematical modelling of the bone remodelling process, including the absence of an osteocyte loop of regulation. It is within this context that this research presented in this thesis utilises a range of modelling methods to develop a framework for bone remodelling which can be used to improve treatment methods for bone disorders. The study concentrated on dynamic and steady state variables that in perspective can be used as constraints for optimisation problem considering bone remodelling or tissue remodelling with the help of the grafts/scaffolds.The cellular and combined allosteric-regulation approaches to modelling of bone turnover, based on the osteocyte loop of regulation, have been studied. Both approaches have been studied different within wide range of rate parameters. The approach to the model validation has been considered, including a statistical approach and parameter reduction approach. From a validation perspective the cellular class of modes is preferable since it has fewer parameters to validate. The optimal control framework for regulation of remodelling has been studied. Future work in to improve the models and their application to bone scaffold design applications have been considered. The study illustrates the complexity of formalisation of the metabolic processes and the relations between hierarchical subsystems in hard tissue where a relatively small number of cells are active. Different types/modes of behaviour have been found in the study: relaxational, periodical and chaotic modes. All of these types of behaviour can be found, in bone tissue. However, a chaotic or periodic modes are ones of the hardest to verify although a number of periodical phenomena have been observed empirically in bone and skeletal development. Implementation of the allosteric loop into cellular model damps other types of behaviour/modes. In this sense it improves the robustness, predictability and control of the system. The developed models represent a first step in a hierarchical model of bone tissue (system versus local effects). The limited autonomy of any organ or tissue implies differentiation on a regulatory level as well as physiological functions and metabolic differences. Implementation into the cellular phenomenological model of allosteric-like loop of regulation has been performed. The results show that the robustness of regulation can be inherited from the phenomenological model. An attempt to correlate the main bone disorders with different modes of behaviour has been undertaken using Paget’s disorder in bone, osteoporosis and some more general skeleton disorders which lead to periodical changes in bone mass, reported by some authors. However, additional studies are needed to make this hypothesis significant. The study has revealed a few interesting techniques. When studying a multidimensional phenomenon, as a bone tissue is, the visualisation and data reduction is important for analysis and interpretation of results. In the study two novel technical methods have been proposed. The first is the graphical matrix method to visualise/project the multidimensional phase space of variables into diagonal matrix of regular combination of two-dimensional graphs. This significantly simplifies the analysis and, in principle, makes it possible to visualise the phase space higher than three-dimensional. The second important technical development is the application of the Monte-Carlo method in combination with the regression method to study the character and stability of the equilibrium points of a dynamic system. The advantage of this method is that it enables the most influential parameters that affect the character and stability of the equilibrium point to be identified from a large number of the rate parameters/constants of the dynamic system. This makes the interpretation of parameters and conceptual verification of the model much easier.

[Truncated abstract] Intracellular communication between osteoclasts and osteoblasts is imperative to maintain bone integrity. A myriad of molecules are responsible for regulating osteoblast and osteoclast activity. In particular, it is well documented that osteoblast-derived factors are crucial in directly controlling osteoclast formation and function. Since bone formation is coupled to bone resorption, it would be expected that osteoclasts also have some role in regulating the growth and function of osteoblast cells. However, despite extensive research upon osteoclast and osteoblast biology, the mechanisms by which osteoclasts regulate osteoblast growth and function is not well understood. In an attempt to further elucidate the mechanisms by which osteoclasts and osteoblasts communicate, the technique of subtractive hybridisation was used to identify a novel osteoclastderived factor identical to that of mouse Seminal Vesicle Secretion VII (SVS VII). Previous characterisation of the gene in bone demonstrated that SVS VII was abundantly and specifically expressed by mature osteoclasts (Phan, 2004). Additional research hinted that SVS VII acted as a novel osteoclast-derived factor, that by paracrine mechanisms, targeted osteoblast function (Phan, 2004). However, it remained open as to whether the SVS VII molecule did uniquely target the osteoblast, and whether this interaction influenced bone formation in vivo. Therefore, this thesis endeavoured to functionally characterise the role of the SVS VII molecule in the bone environment. ... Further work is needed to identigy a clear consensus binding sequence, to determine the specificity of the interaction between SVS VII protein and each phage clone, and to isolate a specific binding partner for SVS VII. In conclusion, the studies of this thesis sought to characterise the significance of SVS VII expression by mature osteoclasts, relative to its effects on osteoblast behaviour, but failed to conclusively determine a role for SVS VII in bone. Given that the effects of SVS VII on in vitro osteoblast activity and function are minimal, it is doubtful that SVS VII primarily acts as a paracrine factor integral to osteoblast function. Therefore, these findings conflict with those presented previously (Phan, 2004). However, it was demonstrated that SVS VII treatment was associated with in vivo effect on the skeleton, suggesting that SVS VII may target other elements of the bone microenvironment. Via mechanisms not yet understood, which possibly involves additional factors of the bone 11 extracellular matrix, SVS VII may target a subset of osteoprogenitor cells within the bone environment and act to regulate their proliferation. Therefore, SVS VII may enhance osteogenic precursor cell number at sites of bone formation which would increase the pool of cells that can differentiate down the osteoblast linage and contribute to bone formation. In this regard, SVS VII might function in a manner homologous to the Ly-6 molecule Sca-1 and act as an important factor that maintains a balance between the bone formation and resorption process. Clearly, more work focusing on alternative facets of bone biology is needed to identify whether there is a significant role for SVS VII in skeletal tissue.

Thesis (Ph.D.)--East Tennessee State University, 2004.
Title from electronic submission form. ETSU ETD database URN: etd-1120104-223525 Includes bibliographical references. Also available via Internet at the UMI web site.

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.

In cases of compromised bone remodeling like osteoporosis, insufficient osseointegration occurs and results in implant failure. Implant retention relies on proper secondary fixation, which is developed during bone remodeling. This process is disrupted in metastatic bone diseases like osteoporosis. Osteoporosis is characterized low bone mass and bone strength resulting from either accelerated osteoclast-mediated bone resorption or impaired osteoblast-mediated bone formation. These two processes are not independent phenomena. In fact, osteoporosis can be viewed as a breakdown of the cellular communication connecting bone resorption to bone formation. Because bone remodeling occurs at temporally generated specific anatomical sites and at different times, local regulators that control cross-talk among the cells of the BRU are important. Previous studies show Ti implant surface characteristics like roughness, hydrophilicity, and chemistry influence the osteoblastic differentiation of human MSCs and maturation of OBs. Furthermore, microstructured Ti surfaces modulate the production of factors shown to be important in the reciprocal communication necessary for the maintenance of healthy bone remodeling. Semaphorin signaling proteins are known to couple the communication of osteoblasts to osteoclasts and are capable of stimulating bone formation or bone resorption depending on certain cues. Implant surface properties can be optimized to exploit these effects to favor rapid osseointegration in patients with osteoporosis.

O objetivo do presente estudo foi comparar a eficácia da implantação de biomateriais porosos na neoformação óssea e reparo de defeitos cervicais mandibulares em cães, com ou sem a técnica de regeneração óssea guiada (ROG). Bio-Oss Block® (BB), Bio-Oss Collagen® (BC), Bio-Oss® em grânulos (BG), osso autógeno (Ab) e coágulo (Cg) foram utilizados nas mesmas situações experimentais. Para o grupo com membrana foi utilizado o BioGide®. Doze cães foram submetidos a extrações dos pré-molares e primeiros molares mandibulares bilateralmente. Quatro meses após cinco defeitos ósseos (6 mm de diâmetro/4 mm de profundidade) foram confeccionados em um lado. Implantes de 3,3 x 10 mm foram instalados na mesial de cada defeito, proporcionando um \"gap\" distal de 2,7 mm. Os defeitos foram aleatoriamente preenchidos com Ab, Cg, BB, BC e BG. Os mesmos procedimentos foram executados no lado oposto após oito semanas. A membrana foi utilizada para recobrir os defeitos em metade dos lados. Os animais foram sacrificados após oito semanas. A estabilidade dos implantes foi aferida pelo Osstell Mentor®, na instalação do implante e no sacrifício. Os espécimes (n=60, sendo 3 de cada grupo) foram escaneados em micro-tomógrafo Skyscan® 1172. Após aquisição das imagens, o volume de interesse de 3,0 x 6,0 x 4,0 mm foi estabelecido e os parâmetros relativos à formação óssea foram avaliados. Todos os biomateriais foram escaneados in vitro para avaliação da porosidade. Utilizando a técnica de cortes por desgaste, lâminas histológicas foram confeccionadas para a avaliação histológica e histométrica de cada espécimen. As análises histométricas revelaram que o BC apresentou formação óssea semelhante ao Ab em 8 semanas sem BGd. O Cg mostrou a maior formação óssea entre os tratamentos testados em 16 semanas com BGd, e foi superior ao BB e BG em 8 semanas sem BGd (p<0,05). O BB exibiu pior formação óssea entre os tratamentos (8 e 16 semanas, com ou sem membrana). O BC obteve o melhor desempenho dentre os biomateriais. Todos os biomateriais foram parcialmente reabsorvidos de 8 a 16 semanas, no entanto, o BB foi encontrado em maior quantidade em comparação com os demais biomateriais (p<0,05). Em relação à análise da crista alveolar, o BB apresentou a menor reabsorção entre os tratamentos, com e sem BGd a 8 e 16 semanas (p<0,05). A aplicação da BGd proporcionou maior ISQ em 16 semanas, independentemente do material testado (p<0,05). A análise micro-tomográfica mostrou que quando a BGd não foi utilizada, o BG proporcionou a maior quantidade de osso no interior do defeito, seguido pelo BC (p<0,05). Quando o defeito foi coberto com BGd, o Ab rendeu superior formação óssea (p>0,05). A análise de superfície óssea mostrou valores aumentados em sítios tratados com BG, seguido por BC em 8 semanas sem BGd, e Ab em 8 semanas com BGd (p<0,05). O BC apresentou superfície/volume ósseo superior a 8 (com e sem BGd) e 16 semanas com BGd (p<0,05). O BB apresentou os menores valores em 16 semanas (sem BGd). O Cg em 16 semanas (com BGd) foi o pior entre os tratamentos aplicados (p<0,05). Em relação à espessura trabecular, Ab e BB apresentaram respectivamente valores maior e menor (p<0,05), independente do tempo experimental avaliado ou uso de membrana. A análise da porosidade dos biomateriais revelou que o BG apresentou maiores números, volume e superfície de poros fechados. O BB apresentou maiores valores de volume de poros abertos, porosidade aberta e porosidade total em comparação com os outros materiais. Conclui-se que a implantação de bloco de alta porosidade (BB) falhou em proporcionar maior reparo ósseo no interior do defeito e foi o tratamento que mais reduziu a reabsorção da crista óssea alveolar distal. Biomateriais com menor porosidade (BC e BG) apresentaram superior ou semelhante formação óssea e estabilidade dos implantes em comparação ao osso autógeno. A utilização da técnica de ROG melhorou o padrão de formação óssea em todos os tratamentos e períodos testados e reduziu a presença de tecido mole no interior do defeito. Uma relação inversa entre a porosidade dos biomateriais e a formação óssea in vivo foi observada no modelo experimental adotado.
The aim of this study was to compare the effectiveness of porous biomaterials in bone formation and repair of cervical mandibular defects in dogs, with or without Guided Bone Regeneration (GBR) technique. Bio-Oss Block® (BB), Bio-Oss Collagen® (BC), Bio-Oss® in granules (BG), autogenous bone (Ab) and coagulum (Cg) were used under the same experimental conditions. For the membrane group, BioGide® was used. Twelve dogs underwent bilateral extractions of mandibular premolars and first molars. After four months five bone defects (6 mm long / 4 mm deep) were prepared at one side. Implants of 3.3 x 10 mm were installed on each of mesial defect, providing a distal gap of 2.7 mm. The defects were randomly filled with Ab, Cg, BB, BC and BG. The same procedures were performed in the opposite side after eight weeks. A membrane was used to cover the defects in half of the sides. Animals were sacrificed after eight weeks. Implant stability was measured by Osstell Mentor®, at implant installation and sacrifice. The specimens (n=60, 3 in each group) were scanned in Skyscan® 1172 micro-CT scanner. A volume of interest of 3.0 x 6.0 x 4.0 mm was established and the parameters related to bone formation were evaluated. All used biomaterials were also scanned for in vitro porosity evaluation. Using Exakt® system, ground section of each specimen were prepared for histological and histometric assessment. Histometric analysis revealed that BC presented similar bone formation to Ab in 8 weeks without BGd. Cg showed greater bone formation between treatments at 16 weeks with BGd, and was superior to BG and BB at 8 weeks without BGd (p<0.05). BB exhibited worse bone formation within treatments (8 and 16 weeks, with or without membrane). BC had the best performance among biomaterials. All biomaterials were partially resorbed from 8 to 16 weeks. However, BB was found in greater amounts in comparison with other biomaterials (p<0.05). Regarding the alveolar crest analysis, BB had the lowest resorption between treatments with and without BGd at 8 and 16 weeks (p<0,05). The BGd use promoted higher final ISQ values at 16 weeks, regardless the tested treatment (p<0.05). Micro-CT analysis showed that when BGd was not used, BG yielded the highest amount of bone within the defect, followed by BC (p<0.05). When the defect was covered with BGd, Ab yielded higher bone formation (p>0.05). Bone surface area analysis showed that increased values in sites treated with BG, followed by BC without BGd at 8 weeks, and Ab at 8 weeks with BGd (p<0.05). The BC presented greater Bone Surface Area/Bone volume at 8 (with and without BGd) and 16 weeks with BGd (p<0.05). BB had the lowest values at 16 weeks (without BGd). Cg presented the worst performance among treatments at 16 weeks (with BGd) (p<0.05). Regarding the Trabecular Thickness, Ab and BB showed the highest and lowest values, respectively (p<0.05), regardless of the time point or membrane use. In biomaterials porosity analysis, BG showed higher numbers, volume, and surface area of closed pores. BB had the highest volume of open pores, open porosity and total porosity compared with the other treatments. It can be concluded the use of a high porosity block (BB) failed to provide greater bone formation within the defect area and it was the treatment that better reduced distal alveolar crest resorption. Biomaterials with lower porosity (BC and BG) showed higher or similar bone formation and implant stability if compared to autogenous bone. The appliance of BGd improved bone formation in all treatments and tested periods and reduced soft tissue presence within the defect. An inverse relationship between biomaterials\' in vitro porosity and in vivo bone formation was observed in the experimental model used.

Current options for maintaining or slowing aging-related bone mineral density (BMD) loss in postmenopausal women primarily include pharmaceutical agents. More recently, physical activity and exercise have been suggested as highly effective, low cost alternatives. Weighted aerobic exercise, utilizing load carriage systems (LCS), is known to increase the gravitational forces impacting bone, creating a higher osteogenic stimulus than standard aerobic exercise. In response to the positive research on aerobic exercise with well-designed LCS, Dr. Lawrence Petrakis, MD, developed a unique 5.44 kg uniformly weighted exercise suit. This study aimed to examine the effects of the uniformly weighted exercise suit on serum biochemical markers of bone formation (Amino- Propeptide of Type 1 Collagen [P1NP]; Carboxy-Terminal Propeptide of Type 1 Collagen [P1CP] and resorption (Carboxy-Terminal Telopeptide of Type 1 Collagen [CTX]) in response to submaximal aerobic exercise in postmenopausal women with low bone density. Nine volunteer, sedentary to lightly active, healthy postmenopausal women (Age: 58.7±1.1 years, BMI: 28.2±1.0, BMD T-score: -1.2±0.5) participated in this within-subjects study, wherein each participant exercised under two counterbalanced conditions (aerobic exercise with [ES] or without [NS] the exercise suit). During each condition, participants walked on a treadmill at 65%-75% of their age-predicted maximum heart rate until they reached their goal caloric expenditure (400kcal). There was a seven-day washout period between sessions. Serum was processed using ELISA protocols to investigate the change in biomarker at 24 and 72 hours post exercise, relative to baseline. The results indicated, when compared to the NS condition, the ES condition elicited a greater positive change in P1CP at 24 hours (Phours following exercise (P0.05). There was no effect of condition on P1NP at any time point (P>0.05). In sum, submaximal aerobic exercise while wearing the uniformly weighted exercise suit elicited an antiresorptive effect on bone collagen resorption with a simultaneous increase in bone collagen formation 24 hours post exercise.

碩士
國防醫學院
解剖學研究所
82
The purposes of this study were:1)to establish an in vitro model of bone formation, 2)to investigate the effects of interleukin-1(IL-1 )on bone formation,3)to establish an in vitro bioassay of osteoclast formation and 4)to clarify the effects of IL-1 on bone resorption. Thirteen-fourteen day BALB/C fetal calvarial cells were obtained and cultured for 3 weeks.With light microscopic observation, quantitation of bone colony and alkaline phosphatase assay, an in vitro model of bone formation could be established. By this model, daily adding of IL-1 was performed during culture of fetal calvarial cells.The effect of IL-1 on bone formation was evaluated using the same methods mentioned above.In addition, 14-day fetal calvarial explant was obtained and cultured for 10 days. Light density mononuclear cells were collected and co- cultured with bone explant.Ten day after co-culture, osteoclasts were formed. By this model,IL-1 was added daily during co-culture.Ten days later, the precise effect of IL-1 on bone resorption was evaluated.The results of this study indicated that:1)a new in vitro model of bone formation was established,2)there was a positive correlation between the number of plated cells and the number of bone clolnies,3)IL-1 exerted a potent dose-dependent inhibition on bone formation,4)a suitable in vitro model of osteoclast formation was established, 5)IL-1 could stimulate bone resorption in a dose- related fashion,6)the increase in the number of osteo- clasts was probably caused by stimulating the fusion of mononuclasr cells and 7)IL-1 could act "uncoupling factor" in bone remodeling process.

博士
中山醫學大學
醫學研究所
101
Ankylosing spondylitis (AS) is a chronic inflammatiory disorder. Inflammation has been reported to promote the differentiation and maturation of the osteoclast, and bone resorption also affects the overexpression of the osteoblast resulting in the bone formation and syndesmophyte. In addition, imbalance of autoimmune tolerance is associated with the occurrence of autoimmune diseases. The higher expression of CD4+ and CD8+ T cells has also been found in AS patients than in healthy controls, and such expression may relate to the imbalance in the negative signal of activated T cells. Receptor activator of nuclear factor kappa B ligand (RANKL) binds to receptor activator of nuclear factor kappa B (RANK) could cause the activation of bone resorption. Osteoprotegerin (OPG) also competes with RANK by binding to RANKL and inhibiting bone absorptions. Therefore, we designed a case-control study to evaluate the association between occurance and clinical features of AS and RANK, RANKL and OPG genetic polymorphisms. A total of 330 AS patients and 330 age- and gender-matched healthy controls were recruited. Results revealed OPG GG genotype carriers had an elevated risk of AS compared with those with the GC and CC genotypes (odds ratio [OR] 1.74, 95% confidence interval [CI] 1.26-2.40). In addition, age of symptom onset and frequency of peripheral arthritis significantly differed among AS patients by different OPG G1181C genotypes. HLA-B27+ patients with the OPG C allele had the earliest age of symptom onset. Therefore, OPG G1181C polymorphism may be associated with AS development and clinical manifestations. MicroRNA (miR)-146a targets TNF-receptor-associated-factor-6 (TRAF-6) and interleukin-1 receptor-associated kinase 1 (IRAK1) to suppress nuclear factor kB (NF-kB) activity. We investigated whether miR-146a rs2910164 G/C, IRAK1 rs3027898 A/C and rs1059703 T/C genetic polymorphisms associated with AS development and clinical characteristics. A total of 450 Taiwanese AS patients and 438 healthy controls were recruited in our study. Pairwise analysis of the miR-146a rs2910164/IRAK1 rs3027898 alleles showed G/A (OR 2.84, 95% CI 1.34-6.03), G/C (OR 1.71, 95% CI 1.27-2.30), and C/A (OR 1.53, 95% CI 1.09-2.16) had a significantly greater risk of AS than the C/C alleles. Such results were found in males, but not in females. In addition, AS patients with miR-146a rs2910164/IRAK1 rs3027898 G/A pairwise alleles had a significantly higher risk of uveitis development than patients with miR-146a rs2910164/IRAK1 rs3027898 C/C pairwise alleles. Therefore, miR-146a rs2910164 and IRAK1 rs3027898 polymorphisms might be associated with the development of AS, as well as its clinical manifestations. Tumor necrosis factor (TNF)-α might induce the inflammation and osteoclastogenesis. In addition, miR-125b expression inhibits the TNF-α expression, and higher miR-155 expression inversely induces TNF-α expression by targeting suppressor of cytokine signaling-1 (SOCS-1). We compared the differences of TNF-α mRNA, miR-125b, miR-155, and SOCS-1 mRNA expressions between AS patients and healthy controls. The influence of rheumatologic drugs on the expressions of these molecules in AS patients was also assessed. Expressions of whole blood TNF-α mRNA, miR-125b, miR-155, and SOCS-1 mRNA were assessed by RT quantitative PCR (RT-qPCR) among 119 AS patients and 120 healthy controls. TNF-α mRNA expression was negatively correlated with miR-125b expression (r = -0.63, p = 0.03); positively correlated with Bath Ankylosing Spondylitis Functional Index (r = 0.82, p < 0.01), erythrocyte sedimentation rate (r = 0.70, p = 0.02), and C-reactive protein (r = 0.79, p < 0.01) in AS patients without taking nonsteroidal antiinflammatory drugs (NSAIDs) or disease-modifying antirheumatic drugs (DMARDs), respectively. But TNF-α mRNA expression was not correlated with bone metabolism in AS patients. The binding of miR-21 and programmed cell death 4 (PDCD4) might inhibit the expression of PDCD4, and further induce the activation of osteoclasts. We compared the difference of miR-21 expression between AS patients and healthy controls, and evaluated the relationships of miR-21, PDCD4 mRNA, and bone erosion in AS patients. The influence of rheumatologic drugs on the expressions of miR-21 and PDCD4 mRNA in AS patients was also assessed. The expressions of serum miR-21 and PDCD4 mRNA were assessed by RT-qPCR among 122 AS patients and 122 healthy controls, and serum CTX was detected using enzyme-linked immunosorbent assay (ELISA). Compared to healthy controls, AS patients had significantly higher levels of miR-21, PDCD4 mRNA, and CTX. In AS patients who were taking neither NSAIDs nor DMARDs, miR-21 expression was negatively correlated with PDCD4 mRNA expression. In addition, positive correlation of miR-21 and CTX level was observed in AS patients (r = 0.35, p < 0.001), especially in those with disease duration < 10 years (r = 0.49, p < 0.001) and active disease (r = 0.51, p < 0.001). Bone morphogenic proteins (BMPs), is secreted by osteoblasts, might influence the bone formation in AS. MiR-29 suppresses Dickkopf 1 (DKK1) and secreted frizzled related protein 2 (sFRP2) of the Wingless (Wnt) inhibitors, and miR-27 also suppresses sFRP1, DKK2, and adenomatous polyposis coli (APC) of the Wnt inhibitors to regulate the Wnt signal pathway. When Wnt signal pathway was activated, it might further induced BMPs expression. We compared the differences of miR-29, miR-27, and their target genes expressions between AS patients and healthy controls. The influence of rheumatologic drugs on the expressions of these molecules in AS patients was also assessed. Results observed that 73 patients with spinal fusion had higher serum levels of BMP-4 and BMP-7 than either 62 healthy controls or 79 patients without spinal fusion (ps < 0.01), respectively. AS patients with spinal fusion and those without spinal fusion also had the significantly increased miR-27b, miR-29a, miR-29b, and lower sFRP1 mRNA and sFRP2 mRNA expressions than healthy controls; respectively. Compared to AS patients without receiving drug treatment, those with receiving drug treatment had a lower miR-27b expression Therefore, BMPs, miR-27, and Wnt inhibitor proteins might relate to the bone formation in AS. Cytotoxic T lymphocyte antigen-4 (CTLA-4) and protein tyrosine phosphatase, nonreceptor 22 (PTPN22) might play the roles in the inhibition of activated T cells in the initial period of autoimmune tolerance. Programmed cell death-1(PD-1) binds programmed cell death-1 ligand 1(PD-L1) and ligand 2 (PD-L2) to induce negative signals that might maintain the balance of immune tolerance during late period. Therefore, we evaluated the effects of CTLA-4, PTPN22, PD-1, PD-L1 and PD-L2 genptypes in AS occurrences. Results revealed subjects with both of PTPN22 CC/CTLA-4 AA or PTPN22 GC/CTLA-4 AA genotypes had a 2.10 fold (95% CI 1.07-4.13) greater risk of AS development than those with other combinations of PTPN22 and CTLA-4 genotypes. In addition, subjects carrying combinations of PD-1 GG + GA/PD-L1 CC/PD-L2 CC genotypes, those carrying combinations of PD-1 AA/PD-L1 CC/PD-L2 CC genotypes, and those carrying combinations of PD-1 GG + GA/PD-L1 AC + AA/PD-L2 CC genotypes had 6.63 (95% CI 1.28-34.46), 4.33 (95% CI 0.36-52.64), and 3.05 (95% CI 2.16-4.32) greater risks of AS development than those with other combinations of PD-1/PD-L1/PD-L2 genotypes; respectively. Our results suggest that PTPN22 G-1123C, CTLA-4 A49G, PD-1 G-536A, PD-L1 A8923C, and PD-L2 C47103T genotypes have the combined effects on AS development. In conclusion, bone resorption, bone formation, and imbalance of immune tolerance-related gene and miRNA, and their target genes might associate with the development of AS and clinical syndromes.

OBJECTIVE: To determine the effect of anti-inflammatory drugs (4- methoxybenzophenone) and (kavain) on bone formation and bone resorption models using a three-dimensional (3D) live calvarial bone METHODS: Utilizing neonatal mouse calvarial bones on a grid system with media designed to cause bone formation or resorption. These models were used to study the effect of 4- methoxybenzophenone and kavain on bone remodeling. The spent media were evaluated by quantitative analysis of tartrate resistant acid phosphatase (TRAP), alkaline phosphatase (ALP) activity and calcium release. The calvaria were stained with neutral red and silver nitrate for histological analysis. RESULTS: Kavain and 4-methoxybenzophenone affected the calvarial bone remodeling by inhibiting resorption. Kavain stimulated bone formation as shown by ALP activity and prevented the transformation of macrophages into osteoclasts as shown by neutral red staining. Kavain prevented resorption as shown by silver nitrate staining. Histological examination of kavain treated bone showed new osteoid formation. The other factor, 4-methoxybenzophenone, had inconsistent effects on bone. Neutral red staining showed no osteoclast differentiation and silver nitrate staining showed no resorption. However calcium release increased in the resorption model and calcium uptake increased in the formation model. There was no effect on ALP or trap activities in either model.

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.