Posts Tagged ‘Osteoblasts’
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
A delicate balance between bone formation and bone resorption is needed for Healthy Bone. This balance is naturally present until menopause in a woman or “Low T” in a man. The main players are OsteoBlasts, OsteoClasts, and OsteoCytes.
OsteoBlasts are cells that build bone by producing bone matrix (Anabolic). OsteoClasts are cells that resorb or take away bone (Resorptive). Both live on the surface of bone. OsteoCytes live inside bone and control the balance of formation and resorption through the hormone Osteoprotegrin (OPG). OPG supresses the number and activity of OsteoClasts.
Estradiol is the hormone that tells the OsteoCytes to make enough OPG to keep the Osteoclasts under control. Women make Estradiol from Estrogen. Men make Estradiol from Testosterone. Women after menopause (about age 50) and men after about age 70 no longer make enough Estradiol to produce enough OPG. Then it is Osteoclasts Gone Wild.
Modern Hormone Replacement Therapy (HRT) is an obvious possibility in a woman. Estrogen is back on board. Prolia (Denosumab in osteoporosis dose), and Evista (Raloxifene), are two novel osteoporosis medications designed to bring unruly OsteoClasts under control. They both mimic the natural process, but in different ways. We will address each in coming posts.
Take Back Control with whatever medication works best for you.
Jay Ginther, MD
Bisphosphonates accumulate in your bone. When OsteoClasts gobble up your bone, bisphosphonates are released into the Osteoclasts and disable or kill the Osteoclasts. This is great news when the problem is Osteoclasts Gone Wild. Bisphosphonates preserve bone by slowing down bone resorption. However, after a few months, bone formation by OsteoBlasts also slows down, resulting in slow bone turnover.
Moderate and balanced bone turnover is good. You repair microcracks in your bone when OsteoClasts resorb the bone around them and OsteoBlasts fill in the void with new bone matrix. A mix of new and old bone is far stronger than all old bone. Some OsteoClast activity is necessary to heal fractures, especially incomplete (stress) fractures. That is where long term bisphosphonates can be too much of a good thing.