Bone Regulators and Osteoporosis Therapy

Abstract

Osteoporosis is a major health problem, affecting more than 200 million people worldwide (Kanis, JA, WHO Scientific Group: Assessment of Osteoporosis at the Primary Health Care Level, 2007). Osteoporotic fractures can result in disability and death.However,inrecentyears,therehavebeentremendousadvancesinknowledge of the cellular physiology of bone and the systemic and local factors that affect bone cellsandmineralmetabolism,leadingtonovelconceptsandnewtherapiestoslowor reverse the pathology. Tools including diagnostic techniques, genetic approaches, and animal models have been important in facilitating these advances. The goal of this volume is to bring this knowledge together in a form that is useful to students, researchers, and practitioners. Each of the 20 chapters is an entity in itself; however, there are also threads and themes that connect them. The volume begins with The Cells of Bone and Their Interactions, by Ansari and Sims, a comprehensive overview of the development, functions, signaling, and coordination of the bone cell types, establishing their roles in modeling and remodeling. The next several chapters review the effects of critical systemic hormones long recognized for their importance to bone and mineral. In PTH and PTHrP Actions on Bone, Suva and Friedman review signaling through the PTH/ PTHrP receptor and insights gained through structure–activity studies of hormone fragments.Theypresent findingsthatestablishdistinctphysiologicalrolesofthetwo hormones. In Vitamin D and Bone, Christakos, Li, DeLa Cruz, Verlinden, and Carmeliet describe the biosynthesis of 1,25-(OH)2D3/calcitriol, the multiple actions of the hormone mediated through the vitamin D receptor (Vdr), and the insight gained through transgenic and knockout models. In Gonadal Hormones and Bone, Yoshida and Wang and I review gonadal hormones and their actions on bone, including receptor interactions, gene responses, and clinical observations. In the chapter Thyroid Hormones, Glucocorticoids, Insulin, and Bone, Lakatos, Szili, Bakos, Takacs, Putz, and Istenes review the actions of these endocrine agents on the skeleton, from basic mechanisms to the bone disorders resulting from excess thyroid and glucocorticoid hormones and types 1 and 2 diabetes.