Novel biological markers in osteoporosis

Bone is a highly specialized supporting framework of the body, characterized by its rigidity, hardness, and power of regeneration and repair. It protects the vital organs, provides an environment for marrow , acts as a mineral reservoir for calcium homeostasis and a reservoir of growth factors and cytokines, and also takes part in acid¿base balance. Bone metabolism is characterized by an intimate cooperation of bone cells including osteoblasts, osteoclasts and osteocytes in order to maintain a regulated amount of bone tissue and the integrity of bone structure. In metabolic bone diseases such as osteoporosis, bone metabolism is altered, leading to bone loss, often accompanied by changes in the microarchitecture, leading to bone fragility. The development of serum and urinary assays for biochemical markers reflecting either enzymatic activities of osteoblasts and osteoclasts or breakdown products of bone tissue has been of high value to investigate the complex pathways of bone metabolism and their alterations in bone diseases, especially in osteoporosis. New biological markers have been developed to be the valuable research tools for investigation the mechanisms of bone metabolism