Body processes

Bone Tissue Remodeling (Bone Reduction) – Function, Task and Diseases

Bone tissue remodeling (bone remodeling)

Bone tissue remodeling corresponds to bone remodeling that is constantly taking place within bone tissue . Bones are adapted to the current load conditions by the remodeling processes of the osteoclasts and osteoblasts . Excessive bone remodeling characterizes Paget’s disease .

What is Bone Tissue Remodeling?

Bone tissue damage is reversible. For example, revision of bone tissue damage aims at remodeling of bone tissue, also known as bone remodeling or bone tissue remodeling.

In the course of this process, old bone tissue is broken down and then replaced by osteoblasts with newly formed bone. Through the processes of bone tissue remodeling, the human body maintains a stable skeletal system . If the repair mechanism did not exist, the human skeleton would show rapid signs of wear and tear. The daily stress on the bones is great. This stress always leaves behind structural damage in the bone tissue, which is compensated for by the remodeling processes.

The remodeling of the bone tissue also reacts to changing load conditions and adapts the structure of the bones to the current loads. Bone remodeling not only helps the skeleton to withstand changing loads, but also plays a crucial role in fracture healing . For example , the processes of remodeling replaced the callus of a healed fracture with fully functional hard bone.

Function & task

The process of bone tissue remodeling is an ongoing bodily process. Although bones are so strong, they are not rigid and static structures, but constantly adapt to changes in external conditions. Every year, for example, around three cortical bones and around a quarter of trabecular bones are remodeled by remodeling. In about ten years, the entire bone mass of a person is completely broken down and built up again.

Bone remodeling requires the simultaneous presence and activity of bone-degrading osteoclasts and bone-building osteoblasts. Because of this, the process of bone tissue remodeling relies on a degree of control, also known as coupling. The exact course of the coupling has not yet been conclusively researched. The bone- building osteocytes play an important role in regulation. The same applies to parathyroid hormone , which stimulates osteoclast differentiation and at the same time has a stimulating effect on osteoblasts. Also vitamin D and cytokines, such as osteoprotegerin or RANKL, play an important role in controlling bone remodeling.

Bone remodeling in adult humans consists of relatively equal proportions of resorption and new synthesis. In people in the growth phase, build-up exceeds breakdown. From the postmenopause , the resorption of the bone remodeling is higher than the new synthesis.

In addition to its support and movement function, bone is the body’s largest reservoir of calcium and phosphates . For this reason, the remodeling of bone tissue is often associated with a regulatory function in the context of calcium and phosphate homeostasis . The mechanism of bone tissue remodeling takes place continuously and therefore does not have to be started separately when calcium or phosphates are required. For this reason, the organism is able to react relatively quickly to fluctuations in the balance of the two substances. So if the calcium level in human blood is too low, rapid compensation is possible thanks to bone remodeling.

Diseases & Ailments

Bone remodeling depends, among other things, on a person’s age. Thus, for example, it is not necessarily to be assessed as a pathological phenomenon if the red modeling in old age manifests itself primarily as resorption and only to a lesser extent as new synthesis of bone tissue. Rather, the doctor speaks of an age-physiological change in this phenomenon. The high proportion of new bone synthesis and the low proportion of resorption in the growth phase can also be seen as physiological in old age.

Nevertheless, bone tissue remodeling can also be affected by pathological changes. If, for example, significantly more tissue is resorbed than is newly synthesized, regardless of age, this phenomenon can definitely be associated with diseases. One of them is tumor-related bone loss, which is one of the complications of bone metastases. Bone is destroyed as part of this phenomenon, resulting in an uncontrolled release of calcium. The calcium causes the calcium level in the blood to rise above the normal level. In this way, more calcium sometimes flows into the kidney than the organ is able to excrete. Because of these connections, many patients with malignant tumors therefore suffer from hypercalcemia.

So-called Paget’s disease also manifests itself in bone remodeling. It is a disease that causes excessive remodeling of bone tissue. The increased remodeling can deform the bones and change the structure in such a way that the bone becomes susceptible to fractures . At the beginning of the course, Paget’s disease manifests itself in abnormally high activity of the osteoclasts. In some cases there is painon. In other cases, the disease remains asymptomatic for a long time and is therefore rarely diagnosed in the early stages. In the course of the disease, the increased bone resorption of the osteoclasts is followed by overactivity of the osteoblasts, which tries to compensate for the degradation processes. The compensation attempts by the osteoblasts result in an uncoordinated and excessive build-up of bone tissue and usually correspond to under-mineralized bone build-up. For this reason, frequent bone fractures are to be expected in late Paget’s disease.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.