Blood Vessel Formation and Function in Bone

The processes of bone development are coupled to the process of angiogenesis. For example, bone cells can secrete vascular endothelial growth factor (VEGF) that can trigger signaling responses in different cell populations expressing VEGF receptors, including the endothelial cells (ECs) that make up blood vessels as well as chondrocytes, osteoblasts, and osteoclasts. On the other hand, vascular cells can release factors that can act upon chondrocytes and osteoblasts. In addition, fibroblast growth factor (FGF) signaling pathway is also an important regulator of vessel growth and bone formation [19].

Diseases of Bones

A bone fracture is a medical condition in which there is a damage in the continuity of the bone. It can be the result of high stress, or a minimal trauma injury as a result of certain medical conditions that weaken the bones, such as osteoporosis and bone cancer. Bone fracture can breaking in the continuity of the periosteum, edema of nearby soft tissues and muscle spasms. The fracture healing is influenced by age, lifestyle, and comorbidities of bone healing [20].

Osteoporosis is a disease where decreased bone strength and increases the risk of a broken bone. It is the most common reason for bone fracture among the elderly and is becoming an increasingly important public health issue. Osteoporosis may be due to lower than normal peak bone mass and greater than normal bone loss. It can occur after menopause and diseases or treatments including alcoholism, anorexia, hyperthyroidism, surgical removal of the ovaries, and kidney diseases. Moreover, lack of enough exercise and smoking are also risk factors. Effective treatments to prevent fragility fractures are available. For example, osteoporosis imaging can identify individuals at risk for fractures who would require pharmacotherapy to reduce fracture risk and also monitor response to treatment [21]. Exercise can help prevent osteoporosis and are also benefit patients with osteoporosis. In addition, adequate calcium and vitamin are needed to prevent and treat osteoporosis [22].

A bone tumor is a neoplastic growth of tissue in bone which can be either benign or malignant. The most common symptom of bone tumors is pain. Some bone tumors may weaken the structure of the bone, causing fractures. Neoplastic transformation is a consequence of maladaptive alterations in the cellular processes normally involved in cell growth, proliferation, differentiation, and survival [23].

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