Csontlebontó

Csontlebontó is a Hungarian term used to describe agents or processes that break down bone tissue. In scientific contexts it is most commonly rendered as csontlebontó sejtek or csontlebontó folyamat, with the standard term in biology being osteoclasts for the cells responsible for bone resorption. The concept refers to the biological and pathological mechanisms that remove mineralized bone matrix during remodeling or disease.

Osteoclasts are multinucleated cells of myeloid origin that resorb bone as part of normal bone remodeling, balancing formation by osteoblasts. They create a resorption lacuna on the bone surface, acidify the local environment with proton pumps (H+-ATPase), and dissolve hydroxyapatite. In the organic phase, proteolytic enzymes such as cathepsin K and various matrix metalloproteinases degrade collagen and other matrix components, allowing net bone loss where resorption exceeds formation.

Regulation of csontlebontó activity occurs mainly through the RANKL-RANK-OPG signaling axis. Osteoblast lineage cells produce RANKL and osteoprotegerin (OPG), which modulate osteoclast differentiation and activity. Hormonal signals (for example parathyroid hormone increasing resorption; calcitonin inhibiting it) also influence csontlebontó function. Clinically, excessive csontlebontás is associated with conditions like osteoporosis and osteolytic lesions in cancer, while insufficient activity can lead to high bone density disorders.

Therapies targeting csontlebontó activity include bisphosphonates and denosumab, which reduce bone resorption by inhibiting osteoclasts. The term serves as a general descriptor for the biology and pathology of bone resorption, with csontlebontó sejtek specifically corresponding to osteoclasts in Hungarian terminology.