Dr David Dempster presented spectacular pictures to the 2012 meeting of the American Society for Bone and Mineral Research (ASBMR). They show clearly the different actions of the anabolic, Teriparatide (Forteo), and the antiresorptive Bisphosphonate, Zolendronate (Reclast). I had seen preliminary pictures at a small, private presentation last year, but the latest bone biopsy studies were incredibly impressive.
Reclast suppresses bone resorption, as do all antiresorptives. This preserves the bone already present. Forteo stimulates new bone matrix formation, including resorbing some old bone and replacing it with new bone. Each strategy works very well in properly chosen individual patients. Neither is best for everyone.
Dr Dempster, of Columbia University in New York, has been the world leader in bone micro-imaging since his electron microscopy studies first showed the micro-details of bone cells 30 years ago. He lead an international team from several research centers, which followed patients before, during, and after treatment with either Reclast or Forteo.
Flourescent Tetracycline dyes are deposited in brand new bone matrix as it is formed. The patients took differently colored Tetracycline for 3 days each before and after a 2 week period before any treatment was given to establish a baseline. Additional dyes were given after 18 months of treatment. Biopsies were then taken which contained up to 4 different dye layers.
We were shown vivid evidence that the antiresorptive Bisphosphonate, Reclast, shuts down most bone formation, as well as resorption. The anabolic, Forteo, showed impressive new bone formation, as well as increased bone resorption and replacement with new bone. Forteo’s action was greatest on the inner surface of the cortical bone (hard) shell adjoining the cancellous (spongy) bone.
Knowing precisely how a medication works is important in choosing the right medication for each patient who needs medication, in addition to Calcium, Vitamin D3 and proper exercise.
Jay Ginther, MD