![]() Thus, the equilibrium between bone formation and resorption is necessary and depends on the action of several local and systemic factors including hormones, cytokines, chemokines, and biomechanical stimulation. ![]() For example, excessive resorption by osteoclasts without the corresponding amount of nerformed bone by osteoblasts contributes to bone loss and osteoporosis, whereas the contrary may result in osteopetrosis. On the other hand, an imbalance of bone resorption and formation results in several bone diseases. Normal bone remodeling is necessary for fracture healing and skeleton adaptation to mechanical use, as well as for calcium homeostasis. This process occurs due to coordinated actions of osteoclasts, osteoblasts, osteocytes, and bone lining cells which together form the temporary anatomical structure called basic multicellular unit (BMU). īone remodeling is a highly complex process by which old bone is replaced by new bone, in a cycle comprised of three phases: (1) initiation of bone resorption by osteoclasts, (2) the transition (or reversal period) from resorption to new bone formation, and (3) the bone formation by osteoblasts. The function of bone lining cells is not well clear, but these cells seem to play an important role in coupling bone resorption to bone formation. There is evidence that osteocytes act as mechanosensors and orchestrators of this bone remodeling process. Despite its inert appearance, bone is a highly dynamic organ that is continuously resorbed by osteoclasts and neoformed by osteoblasts. Bone exerts important functions in the body, such as locomotion, support and protection of soft tissues, calcium and phosphate storage, and harboring of bone marrow. ![]() Introductionīone is a mineralized connective tissue that exhibits four types of cells: osteoblasts, bone lining cells, osteocytes, and osteoclasts. In this review, we discuss the current data about the structure and functions of bone cells and the factors that influence bone remodeling. ![]() It has been suggested that there is a complex communication between bone cells and other organs, indicating the dynamic nature of bone tissue. The increasing knowledge about the structure and functions of bone cells contributed to a better understanding of bone biology. Moreover, osteocytes produce factors that influence osteoblast and osteoclast activities, whereas osteocyte apoptosis is followed by osteoclastic bone resorption. For instance, the coupling from bone resorption to bone formation is achieved by interaction between osteoclasts and osteoblasts. Recently, it has been recognized that, during bone remodeling, there are an intricate communication among bone cells. An imbalance between bone resorption and formation can result in bone diseases including osteoporosis. This process is under the control of local (e.g., growth factors and cytokines) and systemic (e.g., calcitonin and estrogens) factors that all together contribute for bone homeostasis. Bone tissue is continuously remodeled through the concerted actions of bone cells, which include bone resorption by osteoclasts and bone formation by osteoblasts, whereas osteocytes act as mechanosensors and orchestrators of the bone remodeling process.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |