Bone loss

Bone loss is a pathological reduction in bone mass and the structural deterioration of bone tissue, which leads to increased skeletal fragility and a significantly higher risk of fractures (NIH, 2023). It is not a discrete molecular target, such as a single receptor or enzyme, but rather a complex clinical condition or physiological process resulting from an imbalance in the bone remodeling cycle (StatPearls, 2023). Under normal conditions, bone resorption by osteoclasts is coupled with bone formation by osteoblasts; however, in diseases such as osteoporosis or Paget's disease, resorption outpaces formation. While "Bone loss" itself is not a target, various signaling molecules and proteins that regulate this process—such as the Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL), sclerostin, and cathepsin K—are the actual therapeutic targets for drug development (PubMed, 2021). Therapeutic agents like bisphosphonates and monoclonal antibodies are employed to manage bone loss by specifically inhibiting these underlying molecular drivers of resorption or stimulating anabolic pathways to restore density.

Other names

Bone resorptionOsteopeniaOsteoporosisSkeletal degradationDecalcificationReduction in bone mineral density

Drugs used to treat bone loss typically function as either antiresorptive agents, which inhibit osteoclast activity and bone breakdown, or anabolic agents, which stimulate osteoblasts to promote the formation of new bone matrix (PubMed, 2020).