It is both a necessary and a sufficient condition for bone to be lost with age at any surface location that during remodeling the replacement of resorbed bone is incomplete. In both the ilium and the rib, the degree of such focal imbalance is smaller on the intracortical than on the endocortical or cancellous surfaces that are adjacent to bone marrow. The reason for this difference is unknown. ...

To fulfill adequately their functions of support, sustentation and protection for the internal organs and guarantee blood calcium homeostasis, bone tissue is in constant remodeling. Alveolar bone, the primary support structure for teeth, is particularly subjected to continuous and fast remodeling associated with tooth eruption and positional adaptations, as well as with the functional demands o...

Paget’s disease of bone (PDB) is a common disorder which may affect one or many bones. Although many patients are asymptomatic, a variety of symptoms and complications may occur. PDB is a focal disorder of bone turnover characterized by excessive bone resorption coupled with bone formation. PDB begins with a period of increased osteoclastic activity and bone resorption, followed by increased os...

The mass of growing bones increases through changes in outer dimensions and through the net addition of tissue on inner bone surfaces. In this overview I examine bone accrual as it occurs on trabecular (inner) and periosteal (outer) surfaces. In the axial skeleton, the amount of trabecular bone increases during development, because trabeculae grow thicker as a result of bone remodeling with a p...

Despite the apparent inanimate nature of bone, bone is a dynamic living material constantly being renewed and reconstructed throughout the lifetime of an individual. Bone deposition and bone resorption typically occur concurrently, so that bone is remodeled continually. It is this adaptive remodeling process, driven partially in response to functional requirements, that distinguishes living str...

Bone deposition and bone resorption are ongoing dynamic processes, constituting bone remodeling. Some bone tumors, such as osteosarcoma (OS), stimulate focal bone deposition. OS is the most common primary bone tumor in children and young adults. A complex network of genes regulates bone remodeling and alterations in its expression levels can influence the genesis and progression of bone disease...

During life bones constantly adapt their structure to their mechanical environment via a mechanically controlled process called bone remodeling. For trabecular bone, this process modifies the thickness of each trabecula leading occasionally to full resorption. We describe the irreversible dynamics of the trabecular thickness distribution (TTD) by means of a Markov chain discrete in space and ti...

Macrophages have been shown to have pleiotropic functions in various pathophysiologies, especially in terms of anti-inflammatory and regenerative activity. Recently, the novel functions of bone marrow resident macrophages (called osteal macrophages) were intensively studied in bone development, remodeling and tissue repair processes. This review discusses the current evidence for a role of oste...

Bone remodeling depends on the spatial and temporal coupling of bone formation by osteoblasts and bone resorption by osteoclasts; however, the molecular basis of these inductive interactions is unknown. We have previously shown that osteoblastic overexpression of TGF-beta2 in transgenic mice deregulates bone remodeling and leads to an age-dependent loss of bone mass that resembles high-turnover...

INTRODUCTION—Bone turnover suppression in sites that already have a low surface-based remodeling rate may lead to oversuppression that could have negative effects on the biomechanical properties of bone. The goal was to determine how alendronate suppresses bone turnover at sites with different surface-based remodeling rates. METHODS—Dynamic histomorphometric parameters were assessed in trabecul...