Effects of a bisphosphonate (EHDP) on growth, formation, and dissolution of calcium pyrophosphate crystals

Deposition of calcium pyrophosphate (diphosphate) dihydrate crystals (CPPD) in articular cartilage can lead to the disease chondrocalcinosis. Present in synovial fluid, CPPD gives rise to a state of acute inflammation called pseudogout. This paper reports that in the pH interval of biological interest, 5-7, the bisphosphonate (diphosphonate), disodium salt of ethane-1-hydroxy-1,1-bisphosphonicacid (EHDP or etidronate), in concentrations of 5-10 muM, severely inhibits rates of growth and formation of various forms of calcium pyrophosphate crystals, including CPPD, but has no significant effect on their rates of dissolution.