In physiological circumstances, bone resorption and formation are coupled processes. When, however, one predominates over the other the result is a gain or a loss of bone mass. To study this dynamic process, biochemical bone markers have been developed. Osteocalcin and bone alkaline phosphatase better represent bone formation, while pyridinoline, deoxypyridinoline and collagen type I cross-linking (amino and carboxi-terminal) telopeptides, the bone resorption. In the follow up of osteoporosis treatment, the bone resorption markers are more specific and sensitive than the formation markers. During the treatment of post-menopausal osteoporosis with anti-reabsortive therapy, the rate of fall from basal values of resorption markers at 3 or 6 months are related to the increase on bone mass after long-term treatment. The bone markers have applications in a number of diseases of the skeleton including osteoporosis, and helped to understand the pathophysiological mechanisms of many diseases that affect bone tissue. Although they still need better sensibility and specificity to be strongly recommended in the clinical routine, their use should be encouraged to assess risk of fractures in special cases, to aid treatment decisions, and to monitor treatment.
Bone remodeling; Bone markers; Osteoporosis
