Osteoporosis de la posmenopausia: ante el desafío de elegir la estrategia terapéutica / Postmenopausal osteoporosis: facing the challenge of choosing a therapeutic strategy

La osteoporosis de la posmenopausia es una enfermedad crónica y progresiva asociada con un bajo pico de masa ósea o una rápida y persistente pérdida de masa ósea como con-secuencia del déficit de estrógenos endógenos y del envejecimiento. A pesar de que en la actualidad la oferta de medicamentos para su tratamiento en distintas etapas de la vida es muy importante, sigue siendo una enfermedad subdiagnosticada y subtratada a nivel global. La edad, las comorbilidades existentes, los tratamientos concomitantes, el riesgo de caídas, y los antecedentes familiares o personales de fracturas recientes o pasadas tanto como la densidad mineral ósea son factores que deben ser considerados en la evaluación de cada paciente para determinar el grado de riesgo de fractura En aquellos considerados con alto riesgo o riesgo inminente de fractura se recomienda iniciar un tratamiento con algún agente anabólico seguido por un anticatabólico para lograr una rápida reducción del riesgo de fractura. Por último, una adecuada adherencia en el tiempo al tratamiento es clave para alcanzar la mayor eficacia terapéutica dirigida a la reducción de la ocurrencia de fracturas por fragilidad ósea. (AU)

Postmenopausal osteoporosis is a chronic and progressive disease associated with low peak bone mass or a fast and persistent loss of bone mass as a consequence of endogenous estrogen deficiency and aging, and it is an underdiagnosed and undertreated disease worldwide. At present, there is a wide range of drugs available for the treatment of postmenopausal osteoporosis, with appropriate treatments for each phase of this stage of a woman's life. All factors that may increase the risk of bone fragility fracture should be considered at the time of patient assessment. These include age, existing comorbidities, concomitant treatments, risk of falling, family history of fractures or recent or past personal history of fractures, and the results of bone mineral density assessment. In those patients at high risk or imminent risk of fracture, it is recommended to start treatment with an anabolic agent followed by an anticatabolic agent, in order to achieve an immediate reduction of fracture risk. Finally, an adequate adherence to treatment over time will allow achieving the greatest effectiveness of the proposed therapy, which is the reduction of bone fragility fracture events. (AU)

Osteogénesis imperfecta de tipo III en niño ecuatoriano / Osteogenesis imperfecta type III in an Ecuadorian child

Introducción: la osteogénesis imperfecta es una rara enfermedad genética hereditaria caracterizada por su heterogeneidad causada por defectos del tejido conectivo con el rasgo de fragilidad ósea determinante de múltiples fracturas, incluso prenatales; deformidades de huesos largos y columna vertebral y otros síntomas extra-esqueléticos, como escleróticas de color azul, dentinogénesis imperfecta, trastorno de audición y afectación cardiovascular. Objetivo: Presentar un paciente con las características clínicas e imagenológicas de osteogénesis imperfecta de tipo III. Presentación del caso: Niño ecuatoriano de 4 años de edad de baja talla con antecedente de fracturas múltiples desde los 8 meses de nacido, con deformidad en columna vertebral demostrada por radiología por cifoescoliosis en forma de "S" y fracturas vertebrales, con deformidad progresiva en huesos largos; ha sufrido 16 fracturas, no deambula, sensorio presente, orientado en tiempo y espacio, desarrollo cognitivo normal para la edad. La fragilidad ósea del niño según el fenotipo clasifica al diagnóstico de tipo III de osteogénesis imperfecta, el cual es progresivo e invalidante por las deformidades óseas y múltiples fracturas demostradas en exámenes imagenológicos, sin modificaciones en el color de escleróticas, de herencia presumiblemente dominante. Conclusiones: La descripción clínica y radiológica de osteogénesis imperfecta, afección poco conocida, correspondiente al fenotipo III de la enfermedad, reportada en niño ecuatoriano de 4 años de edad, con talla baja que no deambula, expresión de la severidad de su afección genética, con severas alteraciones óseas por su fragilidad con fracturas múltiples en huesos largos y vértebras(AU)

Introduction: Osteogenesis imperfecta is a rare hereditary genetic disease characterized by its heterogeneity caused by connective tissue defects with the feature of bone fragility determining multiple fractures, even prenatal ones; also deformities of long bones and spine, and other extra-skeletal symptoms, such as blue sclerotic, dentinogenesis imperfecta, hearing disorder and cardiovascular affectations. Objective: To present a patient with clinical and radiological findings of osteogenesis imperfect type III. Case presentation: Ecuadorean male child of 4 years old, with a short height, history of multiple fractures from 8 months of age, with spinal deformity demonstrated by radiology due to "S" shaped kyphoscoliosis and vertebral fractures, with progressive deformity in long bones. The boy has suffered 16 fractures, he does not wander, and he is sensory present, oriented in time and space, with normal cognitive development for his age. The bone fragility of the child according to the phenotype classifies in the type III diagnosis of osteogenesis imperfecta, which is progressive and invalidating due to bone deformities and multiple fractures evidenced in imaging tests, without changes in the color of sclerotics and of presumably dominant inheritance. Conclusions: The clinical and radiological description of osteogenesis imperfecta, which is little-known pathology, corresponding to type III phenotype is reported in a 4-year-old boy who, due to his involvement, has a short height and does not wander as a consequence of the severity of bone affectations with fractures in long bones and vertebrae, mainly produced by the fragility of the bones due to his genetic disease(AU)

Osteogénesis imperfecta: revisión de la literatura actual / Osteogenesis imperfecta: review of current literature

La osteogénesis imperfecta (OI) abarca un grupo de enfermedades de origen genético, caracterizadas por un aumento de la fragilidad ósea, debido a una alteración cualitativa y cuantitativa de la masa ósea, que conlleva un riesgo mayor de recurrencia de fracturas y produce deformidades de diversa magnitud, especialmente en los huesos largos. La incidencia en el ámbito mundial es de aproximadamente 1 en 12 000 a 15 000 nacidos vivos. En nuestro país esta patología es poco conocida y además se lleva un sub-registro de los casos que se presentan. Conclusión: La OI es el trastorno hereditario más común del tejido conectivo; en el 90 % de los casos, se debe a las mutaciones de colágeno tipo I. Los tipos I a V son autosómicos dominantes y del VI al XIII son autosómicos recesivos. Las intervenciones terapéuticas existentes no son curativas. El manejo con bifosfonatos puede mejorar significativamente la historia natural de la enfermedad de tipo III y IV.

Osteogenesis imperfecta (OI) covers a group of diseases of genetic origin, is characterized by an increase in fragility of the bones due to a qualitative and quantitative alteration of bone mass, which entails a higher risk of fractures and produce deformities specially of long bones. The incidence worldwide is approximately 1 in 12,000 to 15,000 live births. In our country this pathology is little known and there is an under-reporting of OI cases. Conclusion: OI is the most common inherited disorder of connective tissue. 90% is due to mutations of type I collagen. Type I to type V are autosomal dominant and type VI to type XIII are autosomal recessive. The existing therapeutic interventions are not curative. Management with bisphosphonates can improve the natural history of type III and type IV disease.

Swimming training potentiates the recovery of femoral neck strength in young diabetic rats under insulin therapy

OBJECTIVE: To test whether swimming training benefits femoral neck strength in young diabetic rats under insulin therapy. METHODS: A total of 60 male Wistar rats (age: 40 days) were divided equally into the following six groups: control sedentary, control exercise, diabetic sedentary, diabetic exercise, diabetic sedentary plus insulin and diabetic exercise plus insulin. Diabetes was induced with a unique intraperitoneal injection (60 mg/kg body weight) of streptozotocin. Seven days after the injection and after 12 hours of fasting, the animals with blood glucose levels ≥300 mg/dL were considered diabetic. Seven days after the induction of diabetes, the animals in the exercise groups were subjected to progressive swimming training (final week: 90 min/day; 5 days/week; 5% load) for eight weeks. The animals in the insulin groups received a daily dose of insulin (2-4 U/day) for the same period. RESULTS: Severe streptozotocin-induced diabetes reduced the structural properties of the femoral neck (trabecular bone volume, trabecular thickness and collagen fiber content). The femoral neck mechanical properties (maximum load and tenacity) were also impaired in the diabetic rats. Insulin therapy partially reversed the damage induced by diabetes on the structural properties of the bone and mitigated the reductions in the mechanical properties of the bone. The combination of therapies further increased the femoral neck trabecular bone volume (∼30%), trabecular thickness (∼24%), collagen type I (∼19%) and type III (∼13%) fiber contents, maximum load (∼25%) and tenacity (∼14%). CONCLUSIONS: Eight weeks of swimming training potentiates the recovery of femoral neck strength in young rats with severe streptozotocin-induced diabetes under insulin therapy.

Biomecánica de las fracturas por stress / Biomechanical features of stress fractures

Se define como estrés (stress) tanto la fuerza que una carga externa ejerce sobre un cuerpo sólido como la fuerza reactiva que acompaña a la primera (Ley de Newton), por unidad de área imaginaria transversal a su dirección. Las cargas internas reactivas inducen deformaciones proporcionales del cuerpo. La resistencia del cuerpo a deformarse se llama rigidez. La deformación puede resquebrajar el cuerpo y, eventualmente, producir una fractura por confluencia de trazos. La resistencia del cuerpo a separarse en fragmentos por esa causa se llama tenacidad. La resistencia del cuerpo a la fractura es proporcional al stress que puede soportar sin separarse en fragmentos por deformación (no hay fractura sin deformación y sin stress previo). El stress máximo que un cuerpo puede soportar sin fracturarse resulta de una combinación de ambas propiedades: rigidez y tenacidad, cada una con distintos determinantes biológicos. Una o varias deformaciones del cuerpo pueden provocarle resquebrajaduras sin fracturarlo. La acumulación de resquebrajaduras determina la "fatiga" del material constitutivo del cuerpo, que reduce su rigidez, tenacidad y resistencia a la fractura para la próxima ocasión ("fragilidad por fatiga"). En el caso de los huesos, en general, los términos stress y fatiga tienen las connotaciones amplias referidas, respecto de todas las fracturas posibles. La fatiga predispone a fracturas a cargas bajas, que se denominan (correctamente) "fracturas por fatiga" y también (incorrectamente) "fracturas por stress", para distinguirlas de las que ocurren corrientemente, sin resquebrajaduras previas al trauma, que se denominan (incorrectamente) "fracturas por fragilidad, o por insuficiencia". En realidad, todas las fracturas se producen por stress y por fragilidad o insuficiencia (en conjunto); pero la distinción grosera entre fracturas "por fatiga, o por stress", por un lado, y "por fragilidad" o "por insuficiencia", por otro, aceptando las amplias connotaciones referidas antes, tiene valor en la práctica clínica. Este artículo intenta explicar esas particularidades biomecánicas y describir las distintas condiciones que predisponen a las fracturas "por fatiga o por stress" en la clínica, distinguiéndolas de las fracturas "por fragilidad o por insuficiencia" (manteniendo estas denominaciones) y detallando las características de interés directo para su diagnóstico y tratamiento. (AU)

The term "stress" expresses the force exerted by an external load on a solid body and the accompanying, opposed force (Newton's Law), expressed per unit of an imaginary area perpendicular to the loading direction. The internal loads generated this way deform (strain) proportionally the body's structure. The resistance of the body to strain expresses its stiffness. Critical strain magnitudes may induce micro-fractures (microdamage), the confluence of which may fracture the body. The body's resistance to separation into fragments determines its toughness. Hence, the body's resistance to fracture is proportional to the stress the body can support (or give back) while it is not fractured by the loadinduced strain (no stress, no strain -> no fracture). Therefore, the maximal stress the body can stand prior to fracture is determined by a combination of both, its stiffness and its toughness; and each of those properties is differently determined biologically. One or more deformations of the body may induce some microdamage but not a fracture. Microdamage accumulation determines the fatigue of the material constitutive of the body and reduces body's toughness, leading to a "fatigue-induced fragility". In case of bones, in general, both stress and fatigue have the referred, wide connotations, regarding any kind of fractures. In particular, bone fatigue predisposes to low-stress fractures, which are named (correctly) "fatigue fractures" and also misnamed "stress fractures", to distinguish them from the current fractures that occur without any excess of microdamage, that are named (wrongly) "fragility" or "insufficiency" fractures. In fact, all fractures result from all stress and fragility or insufficiency as a whole; however, the gross distinction between "fatigue or stress fractures", on one side, and "fragility or insufficiency fractures", on the other, accepting the wide connotations of the corresponding terminology, is relevant to clinical practice. This article aims to explain the above biomechanical features and describe the different instances that predispose to "fatigue or stress fractures" in clinical practice, as a different entity from "insufficiency or fragility fractures" (maintaining this nomenclature), and describe their relevant features to their diagnosis and therapy. (AU)

New insights on diabetes and bone metabolism / Novos conceitos em diabetes e metabolismo ósseo

Diabetes mellitus is a common chronic metabolic disease worldwide whose prevalence has increased during the last decades. Besides its more commonly recognized complications, such as macrovascular disease, retinopathy, nephropathy and neuropathy, diabetes related bone disease has gained growing attention. Diabetic patients are more prone to fracture than the general population as well as to low turnover bone disease in the chronic kidney disease setting. In this review, we discuss the relationship between diabetes and bone as well as the pathogenesis of bone fragility in T2D.

Resumos O diabetes mellitus é uma desordem metabólica crônica cuja prevalência tem aumentado no mundo todo ao longo das últimas décadas. Além de suas complicações mais reconhecidas, como a doença macrovascular, retinopatia, nefropatia e neuropatia, as alterações ósseas relacionadas ao diabetes têm ganhado um crescente interesse. Os pacientes diabéticos são mais suscetíveis a fraturas do que a população geral e à doença de baixa remodelação entre os pacientes com doença renal crônica. Nesta revisão, iremos discutir a relação entre diabetes e o tecido ósseo, assim como a patogênese da fragilidade óssea no diabetes tipo 2.

Osteogenesis imperfecta type V: A repost of two Filipino families and review of literature

Osteogenesis imperfecta (Ol) type V is distinct Ol phenotype that has recently been described. Patients with this phenotype present characteristically with interosseous membrane calcification and hyperplastic callus formation. We present the clinical and radiographic characteristics of two Filipino families diagnosed to have Ol type V. Through this review of cases, we aim to educate healthcare providers by highlighting salient clinical and radiographic features to aid in the recognition of this specific Ol phenotype, difficulties in diagnosis, current practices in management and fracture prevention, and issues in genetic counseling.

Growth and Age-Related Abnormalities in Cortical Structure and Fracture Risk

Vertebral fractures and trabecular bone loss have dominated thinking and research into the pathogenesis and the structural basis of bone fragility during the last 70 years. However, 80% of all fractures are non-vertebral and occur at regions assembled using large amounts of cortical bone; only 20% of fractures are vertebral. Moreover, ~80% of the skeleton is cortical and ~70% of all bone loss is cortical even though trabecular bone is lost more rapidly than cortical bone. Bone is lost because remodelling becomes unbalanced after midlife. Most cortical bone loss occurs by intracortical, not endocortical remodelling. Each remodelling event removes more bone than deposited enlarging existing canals which eventually coalesce eroding and thinning the cortex from 'within.' Thus, there is a need to study the decay of cortical as well as trabecular bone, and to develop drugs that restore the strength of both types of bone. It is now possible to accurately quantify cortical porosity and trabecular decay in vivo. The challenges still to be met are to determine whether measurement of porosity identifies persons at risk for fracture, whether this approach is compliments information obtained using bone densitometry, and whether changes in cortical porosity and other microstructural traits have the sensitivity to serve as surrogates of treatment success or failure.