Mechanisms of Bone Resorption - Wheeless' Textbook of Orthopaedics

- Discussion:
- bone resorption involves the dissolution of mineral crystals along w/
breakdown of the bone matrix;
- calcium is probably removed before the matrix is degraded, yet these
events are closely linked;
- once bone mineral dissolution has begun, collagenolytic enzymes may act
on the insoluble collagen molecules and convert them to large, soluble fragments;
- collagenase, cathepsin D, acid protease, acid phosphatase, deoxyribonuclease, and
other acid hydrolases may be in further degradation of collagen fragments;
- resorption is enhanced by acidosis and inhibited by alkalosis;
- low pH may be required as initial step in mobilization of calcium;

- Methods to Quantify Resorption:
- urinary hydroxprolene;
- urinary pyridinoline
- urinary deoxypyridinoline;