Pathophysiology and Pathomorphology of Osteoporosis.

Osteoporosis is a disease that leads to fragility fractures due to the loss of bone mass and bone microstructure. This review presents an update on the fundamental pathophysiological and pathomorphological mechanisms of bone loss. Pathomorphological characteristics such as perforations and microcallus formations are explained. The physiological relevance of the remodeling process and its control by local paracrine, systemic endocrine, and central neural signaling pathways are discussed. Hormones, such as estrogen, follicle stimulating hormone, and leptin, transcription factors, such as Runx2 and osterix, and the wnt signaling pathway are discussed in terms of their roles in bone cell differentiation and function. On the basis of current knowledge, osteoporosis can be diagnosed and treated and fractures can be prevented. However, it is likely that new and even more effective diagnostic and therapeutic strategies will emerge as our understanding of the remodeling process that controls osteoblast and osteoclast function increases.