ABSTRACT
Pre-clinical data have shown that tissue level effects stemming from bisphosphonateinduced suppression of bone remodeling can result in bone that is stronger yet more brittle. Raloxifene has been shown to reduce bone brittleness through non-cellular mechanisms. The goal of this work was to test the hypothesis that raloxifene can reverse the bone brittleness resulting from bisphosphonate treatment. Dog and mouse bone from multiple bisphosphonate dosing experiments were soaked in raloxifene and then assessed for mechanical properties. Mice treated with zoledronate in vivo had lower post-yield mechanical properties compared to controls. Raloxifene soaking had significant positive effects on select mechanical properties of bones from both vehicle and zoledronate treated mice. Although the effects were blunted in zoledronate bones relative to vehicle, the soaking was sufficient to normalize properties to control levels. Additional studies showed that raloxifene-soaked bones had a significant positive effect on cycles to failure (+114%) compared to control-soaked mouse bone. Finally, raloxifene soaking significantly improved select properties of ribs from dogs treated for 3 years with alendronate. These data show that ex vivo soaking in raloxifene can act through non-cellular mechanisms to enhance mechanical properties of bone previously treated with bisphosphonate. We also document that the positive effects of raloxifene soaking extend to enhancing fatigue properties of bone. (AU)
Los datos preclínicos han demostrado que los efectos a nivel de tejido que se derivan de la supresión del remodelado óseo inducida por bifosfonatos puede dar como resultado un hueso que es más fuerte pero más frágil. Está comprobado que el raloxifeno reduce la fragilidad ósea a través de mecanismos no celulares. El objetivo de este trabajo fue probar la hipótesis de que el raloxifeno puede revertir la fragilidad ósea resultante del tratamiento con bifosfonatos. Se emplearon huesos de perro y ratón de múltiples experimentos con diferentes dosis de bifosfonatos los cuales fueron sumergidos en raloxifeno y luego se evaluaron sus propiedades mecánicas. Ratones tratados con zoledronato in vivo mostraron propiedades mecánicas post-rendimiento más bajas en comparación con los controles. Luego de sumergirlos en raloxifeno se observaron efectos positivos significativos en algunas propiedades biomecánicas tanto en los huesos de ratones tratados con vehículo como con zoledronato. Aunque los efectos se atenuaron en los huesos tratados con zoledronato en relación con los tratados con vehículo, el raloxifeno fue suficiente para normalizar las propiedades a niveles basales. Estudios adicionales mostraron que los huesos sumergidos en raloxifeno tuvieron un efecto positivo significativo en los ciclos de fractura (+ 114%) en comparación con los huesos de ratón sumergido en vehículo. Finalmente, el raloxifeno mejoró significativamente las propiedades de costillas de perros tratados durante 3 años con alendronato. Estos datos muestran que la inclusión ex vivo en raloxifeno puede actuar a través de mecanismos no celulares para mejorar las propiedades mecánicas de huesos previamente tratado con bifosfonatos. También documentamos que los efectos positivos del raloxifeno mejoran las propiedades de fatiga del hueso. (AU)
Subject(s)
Animals , Male , Female , Dogs , Mice , Osteogenesis Imperfecta/chemically induced , Osteogenesis Imperfecta/drug therapy , Bone Remodeling/drug effects , Raloxifene Hydrochloride/administration & dosage , Diphosphonates/adverse effects , Biomechanical Phenomena/drug effects , Bone and Bones/physiopathology , Alendronate/adverse effects , Raloxifene Hydrochloride/pharmacology , Disease Models, Animal , Fatigue/drug therapy , Zoledronic Acid/adverse effectsABSTRACT
The objective this study was to summarize long-term risks associated with bisphosphonate therapy. Search of relevant medical publications for data from clinical trials, trial extensions, observational studies and post-marketing reports. Trial extensions and modifications did not reveal significant long-term safety issues. Observational data suggest at least as many benefits as risks. Post-marketing reports of musculoskeletal pain, osteonecrosis of the jaw and atypical femur fractures have been widely circulated in the lay press. Most focus on long-terms risks has been on osteonecrosis of the jaw and atypical femur fractures which occur in patients who have not received bisphosphonate therapy but may be more frequent (though still uncommon) in patients who have been on treatment for 5 years or longer. Lower-risk patients may be able to stop treatment after 3-5 years for a “drug holiday,” which mitigates these long-term risks; for higher risk patients, therapy through 6-10 years appears to be advisable and offers more benefits than risks.
O objetivo deste estudo foi resumir os riscos associados ao tratamento a longo prazo com bisfosfonatos. Foram pesquisadas as publicações médicas relevantes incluindo ensaios clínicos, extensões de ensaios clínicos, estudos observacionais e relatórios pós-comercialização (vigilância farmacológica). As extensões e modificações de ensaios clínicos não indicaram nenhuma situação de alarme quanto à segurança dos bisfosfonatos a longo prazo. Dados observacionais sugerem pelo menos tantos benefícios quanto riscos. Entretanto, relatos pós-comercialização de dor musculoesquelética, osteonecrose da mandíbula e fraturas de fêmur atípicas foram amplamente divulgados na imprensa leiga. O foco nos riscos a longo prazo do tratamento com bisfosfonatos tem sido pincipalmente a osteonecrose da mandíbula e as fraturas atípicas de fêmur. Essas últimas, embora mais frequentes (ainda que pouco comuns) em pacientes que receberam tratamento com bisfosfonatos por 5 anos ou mais, podem ocorrer em indivíduos não tratados com esses medicamentos. Pacientes com baixo risco de fratura podem potencialmente parar o tratamento depois de 3 a 5 anos (“drug holiday”). Esse procedimento reduz os riscos desses medicamentos a longo prazo. Não obstante, nos pacientes de maior risco a terapia por 6 a 10 anos parece ser aconselhável e oferece mais benefícios do que riscos.
Subject(s)
Humans , Bone Density Conservation Agents/adverse effects , Diphosphonates/adverse effects , Osteoporosis/drug therapy , Atrial Fibrillation/chemically induced , Bisphosphonate-Associated Osteonecrosis of the Jaw/etiology , Bone Density Conservation Agents/therapeutic use , Clinical Trials as Topic , Carcinoma/chemically induced , Diphosphonates/therapeutic use , Esophageal Neoplasms/chemically induced , Femoral Fractures/chemically induced , Long-Term Care , Musculoskeletal Pain/chemically induced , Osteonecrosis/chemically induced , Protective Factors , Risk Assessment , Risk FactorsABSTRACT
Se ha efectuado una revisión de los trabajos sobre la fisiopatología del MM y sobre el tratamiento de las lesiones osteoporóticas que se presentan en casi todos los casos. Es sabido que los bifosfonatos son sumamente efectivos por lo que se comentan los actuales esquemas de tratamiento tomando en cuenta los recientes consensos. Hay un acuerdo prácticamente unánime en la eficacia del pamidronato y el zoledronato endovenosos aplicados mensualmente durante dos años, siendo aceptado el uso del clodronato oral en Europa pero no en EE.UU. Aunque mejorarían la calidad de la sobrevida, los bifosfonatos no la prolongarían. Se refieren las precauciones que habría que tomar para evitar la osteonecrosis de mandíbula, una complicación de las dosis altas de bifosfonatos que se ha comunicado con mayor frecuencia durante los últimos años. Se destaca la importancia de la consulta odontológica frecuente y del permanente cuidado dental.
The aim of this review is to discuss recent findings in the physiopathology and treatment of osteoporotic lesions present in almost all patients with MM. The efficacy of bisphosphonates is well known, so we summarize the current treatment schedules according to the most recent consensus. Pamidronate and Zoledronate are equally effective and universally accepted. They should be administered intravenously on a monthly basis for two years. Oral clodronate is accepted in Europe but not in USA. Even if bisphosphonates provide a better quality of life, they do not increase survival. Because osteonecrosis of the jaw has been repeatedly reported after high doses of bisphosphonates, we discuss the necessary precautions to prevent this condition emphasizing frequent dental care and examinations.