Hueso: alteraciones relacionadas con obesidad / Bone: Obesity-Related Disorders

Resumen: El tejido óseo, anteriormente considerado como una estructura mecánica de soporte y movimiento, ha mostrado una participación importante en la homeostasis del organismo, incluyendo al metabolismo energético y el tejido adiposo. En la actualidad se considera un órgano endócrino que sintetiza moléculas reguladoras del metabolismo denominadas osteocinas. A su vez, el tejido adiposo, considerado como una glándula de secreción interna, ayuda a mantener la reserva energética del organismo y produce proteínas y moléculas como las adipocinas, algunas de las cuales afectan directamente al hueso. El análisis del ciclo resorción/formación ósea, muestra que la masa ósea es reflejo del balance entre ambas. Cuando se pierde este balance y hay reducción de la masa ósea con aumento de la fragilidad, aparece la osteoporosis lo que incrementa el riesgo de fractura. Una de cada 3 mujeres y 1 de cada 5 hombres mayores de 50 años presenta una fractura por osteoporosis. La interacción entre tejido adiposo y hueso está mediada por citocinas, osteocinas y adipocinas. La obesidad puede incidir en el hueso por varios mecanismos entre los cuales se encuentran los inflamatorios y los inducidos por citocinas derivadas de los adipocitos como la leptina y la adiponectina que pueden modificar el metabolismo óseo. Evidencias apoyan el efecto negativo de la obesidad sobre la salud del hueso, aunque estudios al respecto aún son contradictorios.

Abstract: The bone tissue, previously considered as a mechanical support for structure and movement, has shown an important participation in the homeostasis of the body, including energy metabolism and adipose tissue. Currently, it is considered an endocrine organ that synthesizes regulatory molecules of metabolism called osteokines. At the same time, the adipose tissue, considered as an internal secretion gland, helps to maintain the body energy and produces proteins and mol ecules such as adipokines, some of which affect the bone directly. The analysis of bone resorption/formation cycle shows that bone mass is a reflection of the balance between both. When this balance is lost and there is a reduction of bone mass with increased fragility, osteoporosis appears and increases the risk of fracture. One in three women and one in five men over 50 years old have a fracture due to osteoporosis. The interaction between adipose tissue and bone is mediated by cytokines, osteokines and adipokines. Obesity may affect the bone by several mechanisms, among which the inflammatory is included and those induced by cytokines secreted by adipocytes such as leptin and adiponectin which can modify bone metabolism. Evidence supports the negative effect of obesity on bone health, although studies about it are still contradictory.

Inmunopatología de la brucelosis osteoarticular / Immunopathology of osteoarticular brucelosis

La brucelosis es una de las enfermedades zoonóticas más importantes a nivel mundial capaz de producir enfermedad crónica en los seres humanos. La localización osteoarticular es la presentación más común de la enfermedad activa en el hombre. Sin embargo, algunos de los mecanismos moleculares implicados en la enfermedad osteoarticular han comenzado a dilucidarse recientemente. Brucella abortus induce daño óseo a través de diversos mecanismos en los cuales están implicados TNF-α y RANKL. En estos procesos participan células inflamatorias que incluyen monocitos/macrófagos, neutrófilos, linfocitos T del tipo Th17 y linfocitos B. Además, B. abortus puede afectar directamente las células osteoarticulares. La bacteria inhibe la deposición de la matriz ósea por los osteoblastos y modifica el fenotipo de estas células para producir metaloproteinasas de matriz (MMPs) y la secreción de citoquinas que contribuyen a la degradación del hueso. Por otro lado, la infección por B. abortus induce un aumento en la osteoclastogénesis, lo que aumenta la resorción de la matriz ósea orgánica y mineral y contribuye al daño óseo. Dado que la patología inducida por Brucella afecta el tejido articular, se estudió el efecto de la infección sobre los sinoviocitos. Estos estudios revelaron que, además de inducir la activación de estas células para secretar quemoquinas, citoquinas proinflamatorias y MMPs, la infección inhibe la muerte por apoptosis de los sinoviocitos. Brucella es una bacteria intracelular que se replica en el retículo endoplásmico de los macrófagos. El análisis de los sinoviocitos infectados con B. abortus indicó que las bacterias también se multiplican en el retículo endoplasmático, lo que sugiere que la bacteria podría usar este tipo celular para la multiplicación intracelular durante la localización osteoarticular de la enfermedad. Los hallazgos presentados en esta revisión intentan responder a preguntas sobre los mediadores inflamatorios implicados en el daño osteoarticular causado por Brucella. (AU)

Brucellosis is one of the most important zoonotic diseases that can produce chronic disease in humans worldwide. Osteoarticular involvement is the most common presentation of human active disease. The molecular mechanisms implicated in bone damage have started to be elucidated. B. abortus induces bone damage through diverse mechanisms in which TNF-α and RANKL are implicated. These processes are driven by inflammatory cells, including monocytes/macrophages, neutrophils, Th17 lymphocytes and B cells. Also, Brucella abortus (B. abortus) can directly affect osteoarticular cells. The bacterium inhibits bone matrix deposition by osteoblast and modifies the phenotype of these cells to produce matrix methalloproteinases (MMPs) and cytokine secretion that contribute to bone matrix degradation. B. abortus also affects osteoclast increasing mineral and organic bone matrix resorption and contributing to bone damage. Since the pathology induced by Brucella species involves joint tissue, experiments conducted in sinoviocytes revealed that besides inducing the activation of these cells to secrete chemokines, proinflammatory cytokines and MMPS, the infection also inhibits sinoviocyte apoptosis. Brucella is an intracellular bacterium that replicate in the endoplasmic reticulum of macrophages. The analysis of B. abortus infected sinoviocytes indicated that bacteria also replicate in their reticulum suggesting that the bacterium could use this cell type for intracellular replication during the osteoarticular localization of the disease. The findings presented in this review try to answer key questions about the inflammatory mediators involved in osteoarticular damage caused by Brucella. (AU)

Osteoporosis and autophagy: What is the relationship? / Osteoporose e autofagia: qual é a relação?

Summary Autophagy is a survival pathway wherein non-functional proteins and organelles are degraded in lysosomes for recycling and energy production. Therefore, autophagy is fundamental for the maintenance of cell viability, acting as a quality control process that prevents the accumulation of unnecessary structures and oxidative stress. Increasing evidence has shown that autophagy dysfunction is related to several pathologies including neurodegenerative diseases and cancer. Moreover, recent studies have shown that autophagy plays an important role for the maintenance of bone homeostasis. For instance, in vitro and animal and human studies indicate that autophagy dysfunction in bone cells is associated with the onset of bone diseases such as osteoporosis. This review had the purpose of discussing the issue to confirm whether a relationship between autophagy dysfunction and osteoporosis exits.

Resumo A autofagia é uma via de sobrevivência celular pela qual proteínas e organelas não funcionais são degradadas nos lisossomos, para reciclagem e geração de energia. Assim, a autofagia é fundamental para a manutenção da homeostase e viabilidade da célula, agindo como um controle de qualidade que evita o acúmulo de estruturas desnecessárias e o estresse oxidativo. Um número crescente de estudos tem demonstrado que disfunções na via autofágica estão relacionadas ao surgimento de diversas doenças, como as neurodegenerativas e o câncer. Estudos também têm indicado que a autofagia exerce um importante papel para a manutenção da homeostase óssea; por exemplo, estudos in vitro e em animais e humanos mostram que disfunções da autofagia nas células ósseas estão associadas ao surgimento de doenças ósseas, como a osteoporose. Nesta revisão, foram abordados esses estudos, a fim de melhor esclarecer se há uma relação entre disfunção autofágica e osteoporose.

Evaluación del efecto del plasma rico en plaquetas en diferentes tiempos y conce ntraciones sobre la viabilidad de fibroblastos de ligamento periodontal y osteoblastos / Evaluation of platelet-rich plasma effect at different times and concentrations on periodontal ligament fibroblast and osteoblast viability

Antecedentes: Los factores de crecimiento utilizados en salud se pueden obtener de una fuente autóloga de primera generación llamada plasma rico en plaquetas (PRP). La diversidad de protocolos para prepararlos genera resultados variables en cuanto al tiempo entre la activación del PRP y sus efectos sobre la proliferación y viabilidad celular. Objetivo: Evaluar proliferación y viabilidad celular de fibroblastos de ligamento periodontal y osteoblastos tratados con PRP en diferentes concentraciones y tiempos de aplicación. Métodos: Se cultivaron líneas celulares de fibroblastos y osteoblastos y se preparó el PRP de sangre venosa de un adulto sano mediante centrifugación, seguido de activación con CaCl2 al 10 %. El efecto sobre la proliferación de las líneas celulares tras la aplicación de PRP y plasma pobre en plaquetas al 1 %, al 3 % y al 5 % se evaluó a las 0, 12, 24, 48 y 72 horas después de su activación mediante MTS. El grupo control consistió en cultivos sin tratamiento. Los datos se analizaron mediante las pruebas de Chi cuadrado, Fischer y McNemar. Resultados: Se observó un aumento de la viabilidad en células tratadas con PRP 24 horas después de su activación en una concentración del 5%. El ensayo de viabilidad celular mostró diferencias estadísticamente significativas entre el grupo experimental y el grupo control (p = 0,05). Conclusión: Los cultivos de fibroblastos y osteoblastos mostraron una tendencia a mayor viabilidad 24 horas después de a la activación con PRP al 5 %.

Background : Growth factors used in health treatments can be obtained from a first-generation source called platelet-rich plasma. The variety of protocols to prepare PRP produces variable results regarding PRP activation time and its effects on cell proliferation and viability. Purpose: To evaluate proliferation and cell viability of periodontal ligament fibroblasts and osteoblasts stimulated with PRP in several concentrations and times after PRP activation. Methods: An in vitro study was carried out using periodontal ligament fibroblast and osteoblast cell cultures. PRP from venous blood of a healthy adult was prepared through centrifugation and activated with 10% CaCl2. The effect on cell proliferation after application of 1%, 3%, and 5% PRP and platelet-poor plasma was evaluated at 0, 12, 24, 48, and 72 hours after activation through MTS. The control group consisted of culture that did not receive any treatment. Data were analyzed using Chi square, Fisher, and McNemar tests. Results: The cell viability assay showed statistically significant differences between the experimental and the control groups. Cell viability increased in cells treated with 5% PRP 24 hours after activation (p = 0.05). Conclusions: Fibroblast and osteoblast cell lines tended to be more viable 24 hours after activation with 5% PRP.

Efectos in vivo del ranelato de estroncio sobre células progenitoras de médula ósea de ratas diabéticas / In vivo effects of strontium ranelate on bone marrow progenitor cells of diabetic rats

La diabetes mellitus (DM) crónica se asocia con reducción en el contenido mineral óseo (osteopenia y osteoporosis). El objetivo de este trabajo fue evaluar la acción del ranelato de estroncio (RaSr) administrado por vía oral a animales control y diabéticos, sobre el potencial osteogénico de células progenitoras de médula ósea (CPMO). Dieciséis ratas Wistar macho jóvenes se dividieron en dos grupos: controles (C) y diabéticas (D) con destrucción parcial de células b-pancreáticas mediante inyecciones intraperitoneales consecutivas de nicotinamida y estreptozotocina. Siete días después de la inyección, cada grupo se subdividió: sin tratamiento, o tratadas oralmente con RaSr (625 mg/kg/día) durante seis semanas, luego de lo cual los animales fueron sacrificados. Las CPMO se obtuvieron de ratas de los cuatro grupos, por lavados del canal diafisario medular (húmero o fémur o ambos) y cultivo hasta confluencia en DMEM-10% FBS. La proliferación celular se evaluó mediante el ensayo de MTT. Luego las CPMO se replaquearon e incubaron en un medio osteogénico durante 14 días (fosfatasa alcalina [FAL] y colágeno tipo 1) o 21 días (mineralización). Las CPMO del grupo C+RaSr mostraron un aumento significativo versus control en la proliferación (133%) y en la diferenciación osteogénica (colágeno 143%, FAL 168%, mineralización 117%). La DM (grupo D) disminuyó significativamente la proliferación y diferenciación osteoblástica de las CPMO. El tratamiento con RaSr (grupo D+RaSr) previno completamente estos efectos antiosteogénicos de la DM. Así, en nuestro modelo experimental in vivo, la DM disminuye el potencial osteogénico de CPMO, efecto que puede ser prevenido por un tratamiento oral con RaSr. (AU)

Chronic diabetes mellitus (DM) is associated with a reduction in bone mineral content (osteopenia and osteoporosis). The object of this study was to evaluate the in vivo effect of he anti-osteoporotic drug strontium ranelate (SrRa) administered orally to control and diabetic animals, on the osteogenic potential of bone marrow progenitor cells (BMPC). Sixteen young male Wistar rats were divided into two groups: control (C) and diabetic with partial beta-cell destruction via consecutive intra-peritoneal injections of nicotinamide and streptozotocin (D). Seven days postinjection, each group was sub-divided: without treatment, or oral treatment with SrRa (625 mg/kg/day) for six weeks, after which the animals were euthanised (groups C, C+SrRa, D, D+SrRa). BMPC were obtained from rats of all four groups by flushing of the diaphysary canal (humerus and/or femur). Adherent cells were then cultured until confluence in DMEM10% FBS. Cell proliferation was evaluated with the MTT mitogenic bioassay. BMPC were replated and incubated in an osteogenic medium for 14 days (determination of alkaline phosphatase [ALP] and type-1 collagen) or 21 days (evaluation of mineralisation). BMPC from C+SrRa rats showed a significant increase versus control in proliferation (133%) and in osteogenic differentiation (collagen 143%, ALP 168%, mineralisation 117%). Induction of diabetes (group D) significantly decreased the proliferation and osteoblastic differentiation of BMPC. Treatment of diabetic animals with SrRa (group D+SrRa) completely prevented these anti-osteogenic effects of Diabetes. Thus, in our experimental in vivo model, Diabetes decreases the osteogenic potential of BMPC, an effect that can be prevented by oral treatment with strontium ranelate. (AU)

Medicamentos para o tratamento da osteoporose: revisão / Drugs for the management of osteoporosis: a review

A osteoporose caracteriza-se por reduzida massa óssea e deterioração microarquitetural do tecido ósseo, o que aumenta a fragilidade óssea e, portanto, a suscetibilidade a fraturas. A osteoporose é um importante problema de saúde pública, que leva a um maior risco de fraturas espontâneas e traumáticas. Na Índia, as fraturas osteoporóticas afetam ambos os sexos e podem ocorrer em idades mais precoces do que nos países do ocidente. Embora sem números precisos, mas com base nos dados disponíveis e na experiência clínica, estima-se que 36 milhões de indianos possam ser afetados pela osteoporose em 2013. Isso estaria associado a um custo enorme e a um consumo considerável de recursos da saúde. Terapias farmacológicas que reduzem de fato o número de fraturas através da melhora da massa óssea acham-se hoje disponíveis no mercado. Atualmente, a maioria dos medicamentos comercializados reduz a perda óssea através da inibição da reabsorção óssea, mas as terapias novas podem aumentar diretamente a massa óssea, como é o caso do paratormônio. As atuais alternativas de tratamento incluem bisfosfonatos, calcitonina, moduladores seletivos do receptor de estrogênio e inibidores da via RANK, sendo que níveis suficientes de cálcio e vitamina D são necessários. Novíssimos agentes tendo os osteoclastos como alvo, tais como a catepsina K e a Src quinase, estão sendo desenvolvidos. As terapias centradas nos osteoblastos incluem os agentes que atuam através da via de sinalização Wnt-β catenina, tais como os inibidores de Dkk-1 e antagonistas de esclerostina. Um maior conhecimento se faz necessário para melhorar as intervenções farmacológicas e as escolhas terapêuticas nesse campo.

Osteoporosis is characterized by low bone mass with micro architectural deterioration of bone tissue leading to enhance bone fragility, thus increasing the susceptibility to fracture. Osteoporosis is an important public health problem leading to an increased risk of developing spontaneous and traumatic fractures. In India osteoporotic fractures occur more commonly in both sexes, and may occur at a younger age than in the western countries. Although exact numbers are not available, based on available data and clinical experience, 36 million Indians may be affected by osteoporosis by 2013. This would be associated with enormous costs and considerable consumption of health resources. Pharmacological therapies that effectively reduce the number of fractures by improving bone mass are now available widely in markets. At present most drugs available in the markets decrease bone loss by inhibiting bone resorption, but the upcoming therapies may increase bone mass by directly increasing bone mass as is the case of parathyroid hormone. Current treatment alternatives include bisphosphonates, calcitonin, selective estrogen receptor modulators and inhibitors of RANK pathway but sufficient calcium and vitamin D are a prerequisite. Newer osteoclast targeted agents like cathepsin K and c-src kinase are under clinical development. The therapies which target osteoblasts include the agents acting through the Wnt-β catenin signaling pathway like Dkk-1 inhibitors and sclerostin antagonists. To further improve pharmacological interventions and therapeutical choices in this field, improvement of knowledge is very necessary.

Enfermedades osteocondensantes: una nueva visión clínico-radiológica soportada en la genética y la inmunoosteología / Osteocondensant diseases: A new clinical-radiological vision supported in genetics and osteoimmunology

Las alteraciones en el remodelado óseo llevan al incremento o disminución de la masa ósea, generando daño de la microarquitectura ósea, lo cual incrementa el riesgo de fractura. Las patologías con incremento de la densidad conducen a diversos procesos osteocondensantes genéticamente dirigidos. La osteocondensación es explicada actualmente por alteración en la función del osteoclasto asociada a una deficiente función de la resorción ósea, alteración en la función del osteoblasto que genera un incremento anormal en la formación ósea, o un imbalance homeostático entre los dos procesos; la expresión clínica y radiológica de estas entidades puede darse en etapas tempranas del desarrollo o en la vida adulta dependiendo del componente autosómico recesivo o dominante respectivamente. En esta revisión, se discute la clasificación basada en el desorden funcional de las células óseas y las principales características clínicas y radiológicas que permiten un abordaje diagnóstico sencillo y aplicable en la práctica clínica.

The alterations in osseous remodeling lead to the increase or decrease of the osseous mass, generating damage to the osseous micro-architecture, which increases the risk of fracture. The pathologies with increase in osseous density lead to different genetically directed osteocondensing processes. The osteocondensing is currently explained by alteration in the function of the osteoclast, associated with a deficient function of the osseous resorption, an alteration in the osteoblast function, which generates an abnormal increase in the osseous formation, or a homeostatic imbalance between the two processes; the clinical and radiological expression of these diseases can take place in early stages of the development, or in the adult life, depending on the recessive or dominant autosomic component, respectively. In this review, the classification based on the functional disorder of the bone cell is discussed, as well as the main clinical and radiological characteristics than permit a simple and applicable diagnostic approach in the clinical practice.

Diferenciação de célula-tronco hematopoética periférica humana em osteoblasto sobre diferentes superfícies de implantes de titânio / Cell differentiation of human haematopoietic stem cell (hHSC) to osteoblast in different surfaces of titanium implant

A associação dos implantes de titânio com tecido ósseo desenvolvido em cultura poderá contribuir para o tratamento de casos clínicos complexos. O objetivo deste trabalho foi viabilizar a formação do tecido a partir da cultura de célula-tronco hematopoética periférica humana (CTHPh) e avaliar o seu crescimento em implantes de titânio, com diferentes superfícies e tamanhos, para definir o melhor resultado. As CTHPhs foram coletadas no sangue periférico por aféresis e cultivadas em meio D-MEN modificado, em placas de cultura com 24 poços, onde foram incluídos implantes de titânio de 3 e 7mm com superfície lisa e texturizada (por jateamento e ataque de ácido), durante 29 dias. A cultura, com corpo-de-prova identificado, teve “cultura controle” sem o corpo-de-prova. Foram avaliados: adesão celular, após 4 horas da inclusão e no 280 dia (D28); curva de crescimento (D1 e D28); atividade da fosfatase alcalina e proteínas totais dos sobrenadantes das culturas (4 horas e D4, D6, D9, D12, D16, D22, D28). Usou-se estatística descritiva na apresentação dos resultados. Concluiu-se que o tamanho dos implantes (3 ou 7mm) não influenciou no desenvolvimento da cultura; quanto à superfície, os implantes texturizados mostraram maior crescimento e adesão celular, maiores valores de atividade da fosfatase alcalina e proteínas totais, apontando para efeito favorável na formação de tecido ósseo in vitro.

The association of titanium implants with cultured bone tissue could contribute to the treatment of complex affections. The aim of this study was to obtain tissue formation from human haematopoietic stem cell (hHSC) and to evaluate the growth in titanium implants, with different surfaces and sizes in order to determine the best results. The hHSC was obtained from blood and cultured for 29 days in 24-well tissue culture plates containing Dulbecco's modified essential medium (Gibco®) and titanium implants of 3 and 7mm with smooth and rough surfaces. Negative controls were included. Were evaluated: cell adhesion after 4 hours of inoculation and again at day 28 (D28): growth curve at day 1 (D1) and day 28 (D28): activity of alkaline phosphatase and total protein from culture supernatant (4 hours, D4, D6, D9, D12, D16, D22, D28). Were applied descriptive statistics to the data. It was concluded that the size of implant (3 or 7mm) did not interfere with development of the culture. Rough surface implants showed increased growth and cell adhesion, greater alkaline phosphatase and total proteins activity, indicating favorable effect to the formation of bone tissue in-vitro.