Univ., Diss., 2010--Marburg.

Resumo: Na dinâmica da reparação óssea os fenômenos de reabsorção e neoformação são dependentes e acoplados. Proteínas efetivamente envolvidas na diferenciação celular determinam ativação ou inibição das atividades que regulam o ganho ou perda de massa óssea. Dentre as proteínas ósseas identificadas e envolvidas na dinâmica óssea podemos destacar a OPG, a RANK e RANKL como marcadores de atividades celulares. O presente trabalho tem como objetivo identificar, nos diferentes períodos da cronologia do processo de reparo alveolar através de técnica imunoistoquímica, a presença das proteínas OPG, RANK e RANKL. Para tanto foram utilizados 60 ratos machos submetidos à exodontia do incisivo superior direito e perfundidos aos 14, 21 e 28 dias pós-operatórios. As hemi-maxilas contendo o alvéolo dental em reparação foram removidas, pósfixadas, descalcificadas em EDTA, crioprotegidas e obtidos cortes longitudinais com 14æm em criostato. Os cortes foram submetidos à reação imunoistoquímica mediante a utilização de anticorpos primários para OPG, RANK e RANKL, como amplificador foi utilizado o sistema avidina-biotina e a diaminobenzidina (DAB) como cromógeno. Os resultados mostram que qualitativamente ocorre um balanço na expressão das proteínas que caracterizam reabsorção e neoformação óssea nos diferentes períodos estudados, onde aos 14 e 21 dias ocorre maior expressão de RANK. Com relação às proteínas OPG e RANKL, observa-se que elas apresentam-se expressas nas células da linhagem osteoblástica de forma similar, sendo que 28 dias é o período de maior expressão destas proteínas. / Abstract: In the bone healing dynamics, the resorption and neoformation processes are dependent. Proteins involved in the cellular differentiation determinate the activation or inhibition of the activities that regulate the gain or loss of bone mass. From all of the identified bone proteins, it may be distinguished the OPG, RANK and RANKL. The present study has the aim to identify, in the different periods of alveolar bone healing chronology, the expression of OPG, RANK and RANKL proteins using the immunohistochemistry methodology. To perform this study, 60 male rats had the right upper incisive extracted and they were perfused at 14, 21 and 28 pos-operative days. The hemimaxilla with the rat extraction socket was removed, pos fixed and decalcified in EDTA. Then, they were cryoprotected and longitudinal slices with 14 ìm thickness were obtained in cryostat. The slices were submitted to immunohistochemistry reaction and the primary antibodies used were against OPG, RANK and RANKL proteins. It was used the avidinbiotin system to amplify the sign and diaminobenzidine was the cromogen. The results show that there is a balance in the expression of the proteins, showing that there is an increase in the expression of RANK at 14 and 21 pos-operative periods. In relation to OPG and RANKL, these proteins presents a similar expression in all of the pos-extraction periods analysed in this study and at 28 days after the extraction there is the greater expression of both proteins. / Orientador: Roberta Okamoto / Coorientador: Roelf Justino Cruz Rizollo / Banca: Idelmo Rangel Garcia Júnior / Banca: Victor Elias Arana-Chavez / Mestre

Osteoporosis is a common complication of many autoimmune diseases that is typically attributed to disease specific factors rather than a direct autoimmune process. This thesis arises from the investigation of a patient with severe high bone turnover osteoporosis who was identified as having autoimmune disease but whose osteoporosis deteriorated despite appropriate treatment. This presentation led to the hypothesis that neutralising autoantibodies to the bone protective cytokine osteoprotegerin (OPG) may have developed. Serum from the index patient, but not healthy controls, was able to immunoprecipitate recombinant OPG protein, demonstrating that OPG had become the target of an autoimmune response. Purified immunoglobulins from the index case were able to inhibit the function of OPG in vitro, by suppressing OPG-mediated inhibition of a luciferase reporter cell line. This represents the first description of disease associated with neutralising antibodies to OPG. Whilst the immunoprecipitation assay did identify OPG antibodies in further patients these results were difficult to quantify. A more robust enzyme linked immunosorbent assay for OPG antibodies was developed using OPG as a capture antigen, which allowed the screening of patient cohorts. Presence of OPG antibodies was defined as a titre greater than the mean plus three standard deviations of 101 healthy volunteers. A low prevalence of 14/864 (1.6%) was seen in a general population cohort and no association with bone density or turnover was seen. An association with higher vascular calcification score in this cohort requires replication. A prevalence of 37/315 (11.7%) was seen in an osteoporosis cohort though no association was seen with bone density or response to treatment. In a coeliac cohort OPG antibodies were identified in 14/282 (5.0%) patients and presence of antibody was independently associated with reduced spine bone density. Functional inhibition of OPG was shown in vitro in 3/14 (21.4%) of the positive cases. Case finding of osteoporosis in the coeliac cohort was not improved by identification of OPG antibodies. These results are consistent with OPG antibodies being pathological in a small number of patients with osteoporosis but a clinical utility of measuring OPG antibodies has not been established.

Osteoporosis and fragility fractures are recognized complications of inflammatory rheumatic diseases. This is thought to result from the effects of chronic inflammation, relative immobility and corticosteroid use. A rare syndrome of osteoporosis in a patient with coeliac disease has been described which results from production of neutralizing antibodies to the bone protective protein osteoprotegerin (OPG). The aim of my thesis is to evaluate prevalence and clinical predictors of osteoporosis in a contemporary cohort of patients with rheumatoid arthritis (RA) and to investigate the role of OPG autoantibodies in the pathogenesis of osteoporosis in rheumatic diseases. In a retrospective cohort study, I found that the overall prevalence of osteoporosis in patients with RA was 29.9% which is in keeping with older reports that recorded a prevalence rate between 17% and 36%. In our contemporary cohort osteoporosis was significantly more common than in a gender and age matched control cohort (17.4%). Further analysis showed that only age and BMI were independent predictors of osteoporosis in RA. A predictive tool based on age and BMI was developed which had 91.4% sensitivity for the detection of osteoporosis in an independent RA population. I went on to screen for the presence of autoantibodies to OPG in patients with various rheumatic diseases. In a study of 75 patients with rheumatoid arthritis and 199 healthy controls OPG autoantibodies were detected in two controls (1%) compared with seven patients with RA (9.3%). The RA patients with detectable OPG antibodies had a longer disease duration, higher DAS28 scores and higher levels of the bone resorption marker CTX than RA patients who did not have autoantibodies. Purified IgG from patients with high levels of OPG antibodies blocked the ability of recombinant OPG to inhibit RANKL induced NFκB activation in a HEK293 cell based assay indicating that they were functional. In a further study of 134 patients with ankylosing spondylitis (AS), 16 patients (11.9%) had detectable OPG antibodies. The presence of OPG-Ab was independently associated with reduced hip bone mineral density and an increased risk of fractures in this population. In patients with a longer disease duration we have also observed that there was a higher discrepancy between spinal and hip BMD in OPG-Ab positive patients compared with OPG ab negative patients (p=0.003). In order to investigate if OPG antibodies affected measurement of serum RANKL concentrations as detected by ELISA using OPG as the capture reagent, I measured OPG ab and free RANKL concentrations in 55 rheumatic disease patients. Surprisingly there was a significant positive correlation between free RANKL and OPG Ab concentrations (r=0.430, p=0.001) which was the opposite to what I had expected. These findings reject the hypothesis that OPG ab block binding of synthetic OPG to RANKL in the ELISA. In conclusion, I have shown that osteoporosis is a common complication in RA and I have developed a new risk prediction tool for the use in clinical practice. I have also found that OPG antibodies are produced more commonly in patients with RA and AS than in healthy controls and that antibody levels correlate with bone resorption markers in RA and bone mineral density in AS patients. In vitro studies have shown that some OPG antibodies have functional effects on RANKL signalling. These findings raise the possibility that OPG antibodies may contribute to the pathogenesis of local and systemic bone loss in rheumatic diseases and signal the need to study the relationship between these antibodies and bone disease in large-scale longitudinal studies.

Bone disease and fractures are common in men and women with chronic kidney disease (CKD). The etiology of fractures in CKD is multi-factorial; identifying risk factors for fracture is important in CKD, so that patients who are at high risk can be treated before they fracture. The majority of studies have focused on risk factors associated with fracture in patients with stage 5 CKD on dialysis–there is a need for studies in pre-dialysis CKD. Three novel, non-radiological factors were assessed in 211 men and women with stage 3-5 CKD: cytokines osteoprotegerin (OPG) and receptor activator of nuclear factor kappa beta ligand (RANKL); tests of neuromuscular function including the timed up and go (TUG), 6 minute walk (6MW), and grip strength; and daily activity levels by accelerometry. Fractures were defined as self-reported low-trauma fractures since the age of 40 and/or prevalent vertebral fractures identified by morphometry. Logistic regression and receiver operating characteristic curves (ROC) were performed using STATA version 11.0. Those with fractures had elevated OPG compared to those without fractures (9.37±4.23 vs. 8.13±3.04 pmol/L, p=0.03), however, after adjusting for age OPG did not differ by fracture status. After adjusting for age, weight, and sex, impairments in both the TUG and 6MW tests were associated with fractures (TUG odds ratio (OR): 1.68, 95% confidence interval (CI): 1.40-2.02; 6MW OR: 0.53, 95% CI: 0.52-0.54). The diagnostic tests characteristics of the TUG and 6MW tests were excellent; both could discriminate fracture status (TUG AUROC: 0.90, 95% CI: 0.84-0.95; 6MW AUROC: 0.87, 95% CI: 0.84-0.95). Overall, subjects were primarily sedentary. After adjusting for stage of CKD, increased sedentary activity and decreased light intensity activity could discriminate fracture status (sedentary AUROC: 0.72, 95% CI: 0.56 to 0.87; light activity AUROC: 0.71, 95% CI: 0.55 to 0.87). In conclusion, non-radiological, novel factors including the TUG, the 6MW, and daily activity, but not OPG or RANKL were able to discriminate fracture status in men and women with stage 3-5 CKD.

Bone disease and fractures are common in men and women with chronic kidney disease (CKD). The etiology of fractures in CKD is multi-factorial; identifying risk factors for fracture is important in CKD, so that patients who are at high risk can be treated before they fracture. The majority of studies have focused on risk factors associated with fracture in patients with stage 5 CKD on dialysis–there is a need for studies in pre-dialysis CKD. Three novel, non-radiological factors were assessed in 211 men and women with stage 3-5 CKD: cytokines osteoprotegerin (OPG) and receptor activator of nuclear factor kappa beta ligand (RANKL); tests of neuromuscular function including the timed up and go (TUG), 6 minute walk (6MW), and grip strength; and daily activity levels by accelerometry. Fractures were defined as self-reported low-trauma fractures since the age of 40 and/or prevalent vertebral fractures identified by morphometry. Logistic regression and receiver operating characteristic curves (ROC) were performed using STATA version 11.0. Those with fractures had elevated OPG compared to those without fractures (9.37±4.23 vs. 8.13±3.04 pmol/L, p=0.03), however, after adjusting for age OPG did not differ by fracture status. After adjusting for age, weight, and sex, impairments in both the TUG and 6MW tests were associated with fractures (TUG odds ratio (OR): 1.68, 95% confidence interval (CI): 1.40-2.02; 6MW OR: 0.53, 95% CI: 0.52-0.54). The diagnostic tests characteristics of the TUG and 6MW tests were excellent; both could discriminate fracture status (TUG AUROC: 0.90, 95% CI: 0.84-0.95; 6MW AUROC: 0.87, 95% CI: 0.84-0.95). Overall, subjects were primarily sedentary. After adjusting for stage of CKD, increased sedentary activity and decreased light intensity activity could discriminate fracture status (sedentary AUROC: 0.72, 95% CI: 0.56 to 0.87; light activity AUROC: 0.71, 95% CI: 0.55 to 0.87). In conclusion, non-radiological, novel factors including the TUG, the 6MW, and daily activity, but not OPG or RANKL were able to discriminate fracture status in men and women with stage 3-5 CKD.

Metastases to bone are observed in around 80% of prostate cancer patients and represent the most critical complication of advanced prostate cancer. Unlike other solid tumors that are associated with osteolytic bone metastases, prostate cancer bone metastases stimulate osteoblastic activity with sclerosis in the bone lesions as a consequence. Osteoprotegerin (OPG) is part of a system with three proteins that play a key role in bone remodeling; namely OPG, RANK and RANKL. RANKL regulates osteoclast activity by binding to RANK on the osteoclasts surface, and this interaction is interrupted by OPG. OPG also plays a role in the lifecycle of tumor cells by blocking TNF-related apoptosis-inducing ligand (TRAIL) making it possible for them to evade cell death. The aim of this thesis was to investigate the interaction between the OPG/RANK/RANKL system and prostate cancer. Data showed that there was production of OPG from prostate cancer cell lines in vitro. This expression was under the influence of cytokines that are present in the microenvironment of bone. Further, there was documented a previously unnoticed cell surface expression of RANKL. Co-culturing the prostate cancer with human osteoblasts increased the expression of RANKL. To connect these findings with in vivo studies, OPG-gene single nucleotide polymorphisms (SNP) were investigated. To evaluate OPG SNPs association with bone, a cohort of elderly men was used. OPG SNPs was shown to be correlated to bone mineral density at hip and spine. There was also an association to fragility fractures. Then there was examined the association of the same SNPs to the incidence of prostate cancer but after a four-year follow-up there was no association to the genetic variants. To summarize this research, we hereby present data that the OPG/RANK/RANKL system might be relevant for prostate cancer growth in bone, and for the skeletal related morbidity in this disease. Future in vitro and in vivo studies will demonstrate the relative importance of this crosstalk, and whether pharmacological interference with the system might be used as a therapeutic tool aiming to decrease skeletal morbidity and possibly also prolong survival in prostate cancer.

Made available in DSpace on 2014-06-11T19:23:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-19Bitstream added on 2014-06-13T18:19:49Z : No. of bitstreams: 1 coutinho_ccc_me_araca.pdf: 114919 bytes, checksum: 49f558e8cba145ffdabb2e45dc62ada3 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Na dinâmica da reparação óssea os fenômenos de reabsorção e neoformação são dependentes e acoplados. Proteínas efetivamente envolvidas na diferenciação celular determinam ativação ou inibição das atividades que regulam o ganho ou perda de massa óssea. Dentre as proteínas ósseas identificadas e envolvidas na dinâmica óssea podemos destacar a OPG, a RANK e RANKL como marcadores de atividades celulares. O presente trabalho tem como objetivo identificar, nos diferentes períodos da cronologia do processo de reparo alveolar através de técnica imunoistoquímica, a presença das proteínas OPG, RANK e RANKL. Para tanto foram utilizados 60 ratos machos submetidos à exodontia do incisivo superior direito e perfundidos aos 14, 21 e 28 dias pós-operatórios. As hemi-maxilas contendo o alvéolo dental em reparação foram removidas, pósfixadas, descalcificadas em EDTA, crioprotegidas e obtidos cortes longitudinais com 14æm em criostato. Os cortes foram submetidos à reação imunoistoquímica mediante a utilização de anticorpos primários para OPG, RANK e RANKL, como amplificador foi utilizado o sistema avidina-biotina e a diaminobenzidina (DAB) como cromógeno. Os resultados mostram que qualitativamente ocorre um balanço na expressão das proteínas que caracterizam reabsorção e neoformação óssea nos diferentes períodos estudados, onde aos 14 e 21 dias ocorre maior expressão de RANK. Com relação às proteínas OPG e RANKL, observa-se que elas apresentam-se expressas nas células da linhagem osteoblástica de forma similar, sendo que 28 dias é o período de maior expressão destas proteínas. / In the bone healing dynamics, the resorption and neoformation processes are dependent. Proteins involved in the cellular differentiation determinate the activation or inhibition of the activities that regulate the gain or loss of bone mass. From all of the identified bone proteins, it may be distinguished the OPG, RANK and RANKL. The present study has the aim to identify, in the different periods of alveolar bone healing chronology, the expression of OPG, RANK and RANKL proteins using the immunohistochemistry methodology. To perform this study, 60 male rats had the right upper incisive extracted and they were perfused at 14, 21 and 28 pos-operative days. The hemimaxilla with the rat extraction socket was removed, pos fixed and decalcified in EDTA. Then, they were cryoprotected and longitudinal slices with 14 ìm thickness were obtained in cryostat. The slices were submitted to immunohistochemistry reaction and the primary antibodies used were against OPG, RANK and RANKL proteins. It was used the avidinbiotin system to amplify the sign and diaminobenzidine was the cromogen. The results show that there is a balance in the expression of the proteins, showing that there is an increase in the expression of RANK at 14 and 21 pos-operative periods. In relation to OPG and RANKL, these proteins presents a similar expression in all of the pos-extraction periods analysed in this study and at 28 days after the extraction there is the greater expression of both proteins.

Made available in DSpace on 2016-06-07T17:12:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-19. Added 1 bitstream(s) on 2016-06-07T17:16:36Z : No. of bitstreams: 1 000863888.pdf: 1762312 bytes, checksum: 33f6a96aaa02314d08de10f973bdf6e4 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Introdução: apesar do sucesso quanto à perda de peso e controle das comorbidades, as cirurgias bariátricas, como o Bypass Gástrico em Y de Roux (BGYR), promovem alterações no metabolismo hormonal e do tecido adiposo, as quais podem se associar a maior remodelação e perda ósseas. Entre os possíveis mecanismos envolvidos estão a influência de adipocinas sobre a modulação da expressão do ligante do receptor ativador do fator nuclear kappa β (RANKL) e da osteoprotegerina (OPG) e o aumento da expressão de esclerostina, em resposta à redução da carga mecânica. Objetivos: avaliar o efeito da perda de peso e das alterações hormonais, após o BGYR, sobre o metabolismo ósseo. Casuística e métodos: foram avaliadas mulheres com obesidade graus II e III, no menacme, submetidas ao BGYR no Hospital das Clínicas de Botucatu, antes e após três, 12 e 24 meses de cirurgia, quanto aos dados antropométricos e laboratoriais [paratormônio (PTH), fosfatase alcalina total (FA total) e fração óssea (BSAP), Interligadores C-Terminais do colágeno Tipo I (CTX), 25 hidroxi-vitamina D (25-OH-Vit D), leptina, adiponectina, RANKL, OPG e esclerostina]. Resultados: observou-se redução de leptina [34,4 (14,7; 51,9) para 22,5 (1,9; 52,7) ng/mL] e OPG [3,6 (1,1; 11,5) para 3,4 (1,5; 6) pmol/L] após o procedimento, com aumento de adiponectina [7,4 (1,7; 18,4) para 13,8 (3,0; 34,6) μg/mL], CTX [0,2 (0,1; 2,2) para 0,6 (0,4; 6,0) ng/mL], RANKL [0,1 (0,0; 0,5) para 0,3 (0,0; 2,0)pmol/L] e esclerostina [21,7 (3,2; 75,1) para 34,8 (6,4; 80,5) pmol/L], após três meses de acompanhamento. A BSAP também aumentou, após 12 meses de procedimento [10,1 (5,4; 18,9) para 13,9 (6,9; 30,2) μg/mL] (p<0,005). O CTX apresentou correlação inversa com o peso (r= -0,451), MG (r= -0,418) e MLG (r= -0,417). Houve correlação positiva entre o CTX e a FA total após 12 meses de BGYR e entre a BSAP e o PTH aos 24 meses de pós-operatório (r= 0,490). Esse marcador... / Introduction: despite the success at weight loss and control of comorbidities, bariatric surgeries such as gastric bypass Roux-Y (RYGB), promote changes in hormone metabolism and adipose tissue, which may be associated with increased remodeling and bone loss. Among the possible mechanisms involved are the adipokines influence on the modulation of the expression of the receptor activator of nuclear factor kappa β ligand (RANKL), and osteoprotegerin (OPG), and increased expression of sclerostin in response to the reduction of the mechanical load. Objectives: evaluate the effect of weight loss and hormonal changes following the RYGB, on the bone metabolism. Methods: women were evaluated with obesity grades II and III in premenopausal, submitted to RYGB at the Botucatu School of Medicine University Hospital (HC-FMB), prior, three, 12 and 24 months after the procedure, as the anthropometric and laboratory data [parathyroid hormone (PTH), total alkaline phosphatase (FA total) and bone fraction (BSAP), interconnectors collagen C-terminal type I (CTX), 25-hydroxy vitamin D (25-OH Vit-D), leptin, adiponectin, RANKL, OPG and sclerostin]. Results: leptin reduction was observed [34.4 (14.7; 51.9) to 22.5 (1.9; 52.7) ng / ml] and OPG [3,6 (1,1; 11 5) to 3.4 (1.5, 6) pmol / L] after the procedure, with an increase of adiponectin [7.4 (1.7; 18.4) to 13.8 (3.0, 34, 6) ug / ml] CTX [0.2 (0.1, 2.2) to 0.6 (0.4, 6.0) ng / ml] RANKL [0.1 (0.0, 0 5) to 0.3 (0.0; 2.0) pmol / L] and sclerostin [21.7 (3.2; 75.1) to 34.8 (6.4; 80.5) pmol / L], after three months of follow-up. The BSAP also increased after 12 months of the procedure [10.1 (5.4, 18.9) to 13.9 (6.9, 30.2) mg / mL] (p <0.005). The CTX showed an inverse correlation with weight (r = -0.451), BF (r = -0.418) and FFM (r = -0.417). There was a positive correlation between CTX and total FA 12 months after RYGB and between the BSAP and PTH at 24 months after surgery (r = 0.490). This marker was negatively ...

Orientador: Gláucia Maria Ferreira da Silva Mazeto / Coorientador: Adriana Lúcia Mendes / Banca: Célia Regina Nogueira / Banca: Vânia dos Santos Nunes / Banca: José Gilberto Henriques Vieira / Banca: Marise Lazaretti Castro / Resumo: Introdução: apesar do sucesso quanto à perda de peso e controle das comorbidades, as cirurgias bariátricas, como o Bypass Gástrico em Y de Roux (BGYR), promovem alterações no metabolismo hormonal e do tecido adiposo, as quais podem se associar a maior remodelação e perda ósseas. Entre os possíveis mecanismos envolvidos estão a influência de adipocinas sobre a modulação da expressão do ligante do receptor ativador do fator nuclear kappa β (RANKL) e da osteoprotegerina (OPG) e o aumento da expressão de esclerostina, em resposta à redução da carga mecânica. Objetivos: avaliar o efeito da perda de peso e das alterações hormonais, após o BGYR, sobre o metabolismo ósseo. Casuística e métodos: foram avaliadas mulheres com obesidade graus II e III, no menacme, submetidas ao BGYR no Hospital das Clínicas de Botucatu, antes e após três, 12 e 24 meses de cirurgia, quanto aos dados antropométricos e laboratoriais [paratormônio (PTH), fosfatase alcalina total (FA total) e fração óssea (BSAP), Interligadores C-Terminais do colágeno Tipo I (CTX), 25 hidroxi-vitamina D (25-OH-Vit D), leptina, adiponectina, RANKL, OPG e esclerostina]. Resultados: observou-se redução de leptina [34,4 (14,7; 51,9) para 22,5 (1,9; 52,7) ng/mL] e OPG [3,6 (1,1; 11,5) para 3,4 (1,5; 6) pmol/L] após o procedimento, com aumento de adiponectina [7,4 (1,7; 18,4) para 13,8 (3,0; 34,6) μg/mL], CTX [0,2 (0,1; 2,2) para 0,6 (0,4; 6,0) ng/mL], RANKL [0,1 (0,0; 0,5) para 0,3 (0,0; 2,0)pmol/L] e esclerostina [21,7 (3,2; 75,1) para 34,8 (6,4; 80,5) pmol/L], após três meses de acompanhamento. A BSAP também aumentou, após 12 meses de procedimento [10,1 (5,4; 18,9) para 13,9 (6,9; 30,2) μg/mL] (p<0,005). O CTX apresentou correlação inversa com o peso (r= -0,451), MG (r= -0,418) e MLG (r= -0,417). Houve correlação positiva entre o CTX e a FA total após 12 meses de BGYR e entre a BSAP e o PTH aos 24 meses de pós-operatório (r= 0,490). Esse marcador... / Abstract: Introduction: despite the success at weight loss and control of comorbidities, bariatric surgeries such as gastric bypass Roux-Y (RYGB), promote changes in hormone metabolism and adipose tissue, which may be associated with increased remodeling and bone loss. Among the possible mechanisms involved are the adipokines influence on the modulation of the expression of the receptor activator of nuclear factor kappa β ligand (RANKL), and osteoprotegerin (OPG), and increased expression of sclerostin in response to the reduction of the mechanical load. Objectives: evaluate the effect of weight loss and hormonal changes following the RYGB, on the bone metabolism. Methods: women were evaluated with obesity grades II and III in premenopausal, submitted to RYGB at the Botucatu School of Medicine University Hospital (HC-FMB), prior, three, 12 and 24 months after the procedure, as the anthropometric and laboratory data [parathyroid hormone (PTH), total alkaline phosphatase (FA total) and bone fraction (BSAP), interconnectors collagen C-terminal type I (CTX), 25-hydroxy vitamin D (25-OH Vit-D), leptin, adiponectin, RANKL, OPG and sclerostin]. Results: leptin reduction was observed [34.4 (14.7; 51.9) to 22.5 (1.9; 52.7) ng / ml] and OPG [3,6 (1,1; 11 5) to 3.4 (1.5, 6) pmol / L] after the procedure, with an increase of adiponectin [7.4 (1.7; 18.4) to 13.8 (3.0, 34, 6) ug / ml] CTX [0.2 (0.1, 2.2) to 0.6 (0.4, 6.0) ng / ml] RANKL [0.1 (0.0, 0 5) to 0.3 (0.0; 2.0) pmol / L] and sclerostin [21.7 (3.2; 75.1) to 34.8 (6.4; 80.5) pmol / L], after three months of follow-up. The BSAP also increased after 12 months of the procedure [10.1 (5.4, 18.9) to 13.9 (6.9, 30.2) mg / mL] (p <0.005). The CTX showed an inverse correlation with weight (r = -0.451), BF (r = -0.418) and FFM (r = -0.417). There was a positive correlation between CTX and total FA 12 months after RYGB and between the BSAP and PTH at 24 months after surgery (r = 0.490). This marker was negatively ... / Doutor