Posts Tagged ‘Bone Matrix’
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
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.
Are your bones still good enough and just need to be maintained? Or have you fractured several times and need to rebuild your bones? Are Steroid Inhalers supressing your Osteoblasts – the cells that build new bone? (not good) Or have your Osteoclasts – the cells that eat away bone – gone wild (even worse) now that you are post-menopausal or an older guy?
Different problems require different classes of medication. Bisphosphonates, Hormone Replacement Therapy, Synthetic Estrogen Receptor Modifier – Evista, and RANK-Ligand Antibody – Prolia, are all Antiresorptives, which act in different ways. They slow down the Osteoclasts that have gone wild and are eating up the bone. The Anabolic, Forteo, stimulates the Osteoblasts that make new bone matrix. Antiresorptive and Anabolic are radically diferent actions.