Posts Tagged ‘osteoclasts’
Forteo (Teriparatide) increases the thickness of the struts making up spongy (cancellous) bone. Forteo is the only osteoporosis medication to do that. It also makes the hard outer shell (cortical bone) thicker. How? Forteo stimulates OsteoBlasts. They make bone matrix, the collagen protein that is more than 80% of bone.
Forteo also stimulates bone turnover. Healthy bone is constantly being resorbed and replaced. This allows bone to eliminate the micro-cracks that gradually accumulate with activity. Bone is strongest when it is a mixture of older more calcified (stiffer) material mixed thoroughly with younger less calcified (somewhat bendable) material. Cracks cannot enlarge. Strength is better. More force is required to fracture the bone.
Anabolic medication for osteoporosis actually increases bone thickness and strength! Antiresorptive medications for osteoporosis (Fosamax, Alendronate, Actonel, Atelvia, Boniva, Evista, Reclast, Prolia) only preserve bone.
We have talked about all of the Antiresorptive medications over the last 2 months. They are excellent treatment if slowing down the OsteoClasts (cells that eat away your bone) is sufficient. That is not always the case.
Now it is time to talk about something completely different. Anabolic medication stimulates the OsteoBlasts (cells that make new bone matrix). OsteoBlasts can rebuild your bones. If you have Fractures, your bones may need to be rebuilt.
Forteo (Teriparatide) is the only Anabolic medication for osteoporosis in the USA. Close cousins of Forteo are available in other countries.
You may need the Anabolic, Forteo, if you have a hip fracture, multiple other fractures, or if VFA testing reveals a Vertebral Compression Fracture. A DXA T-score well below -2.5 can be reason enough without fracture.
Glucocorticoid (Cortico-Steroid) medications (Prednisone, Steroid Inhalers) specifically supress OsteoBlasts (cells that make new bone). Stimulating the OsteoBlasts with the Anabolic, Forteo, can offset the bone loss from Steroid medications. Smoking also supresses OsteoBlasts, leading to bone loss. Stopping Smoking would be best, but Forteo can help.
Not everyone needs an Anabolic, but some individuals do. A Complete Bone Health Evaluation will tell you if an Anabolic is right for you.
More about Forteo (Teriparatide) next time.
Jay Ginther, MD
Aromatase Inhibitors (AI) do a great job treating Breast Cancers which are Estrogen dependent. The AI wipe out all Estrogen thereby depriving the breast cancer of a needed stimulus.
Unfortunately, Aromatase Inhibitor treatment will also do considerable damage to your bones unless you take medication to protect your bones. The good news is that we have medication which can completely offset the harm AI treatment could do to your bones. But, you have to take it, and the sooner you start, the better.
Prolia (Denosumab for Osteoporosis) is specifically approved by the FDA for use in patients using Aromatase Inhibitors (AI) for their breast cancer. Prolia is specifically for women without metastases. Prolia can delay and/or prevent matastases when given early. Xgeva (Denosumab for Cancer) is used if metastases are already present.
Denosumab (Prolia) mimics the natural process that keeps OsteoClasts (the cells that gobble up bone) under control before menopause. OsteoCytes release Osteoprotegrin (OPG) when Estrogen (or Testosterone) is on board. OPG controls the formation and activation of OsteoClasts by blocking RANK-Ligand, which is necessary for OsteoClast formation and activation. This decreases fracture risk.
Prolia mimics OPG and blocks RANK-Ligand, thus blocking bone resorption by preventing OsteoClasts. It is a RANK-Ligand Antibody. It is like birth control for OsteoClasts. Prolia is given as a shot under the skin twice a year. Prolia is very effective at first, but begins to fade by 6 months. Without another injection , Prolia has totally lost effectiveness by 12 months after the last shot.