Bone metabolism and cardiovascular function update. The estimation of bone material quality in the concept of bone and vascular linkage

: It has become clear that a reduction in sex hormones from middle age onwards, increasing age, and an increase in oxidative stress related to lifestyle-related diseases can also reduce bone material properties in terms of collagen post-translational modification, crosslink formation. These changes lead to both qualitative and quantitative abnormalities in collagen, which is the major bone matrix protein. The intermolecular cross-link formation of collagen, which regulates bone-material attributes, is a mechanism independent of bone remodeling. In other words, cross-link formation is controlled by the environment surrounding the bone matrix, comprising cellular functions, oxidative stress, and glycation level. Because oxidative stress is also risk factor of arteriosclerosis and cardiovascular event, there is link between low bone quality and arteriosclerosis. High levels of pentosidine in urine or blood, or mild hyperhomocysteinemia which suggest bone collagen abnormalities, might be used as surrogate markers for evaluating bone quality, assessing the risk of bone fracture. Patients with osteoporosis can be divided into 3 types on the basis of bone density and with bone quality. We are entering an age in which the treatment of osteoporosis will be personalized, with drugs administered depending on these types.