Increased formation and decreased resorption of bone in mice with elevated vitamin D receptor in mature cells of the osteoblastic lineage
The microarchitecture of bone is regulated by complex interactions between the bone-forming and resorbing cells, and several compounds regulate both actions. For example, vitamin D, which is required for bone mineralization, also stimulates bone resorption. Transgenic mice overexpressing the vitamin D receptor solely in mature cells of the osteoblastic bone-forming lineage were generated to test the potential therapeutic value of shifting the balance of vitamin D activity in favor of bone formation. Cortical bone was 5% wider and 15% stronger in these mice due to a doubling of periosteal mineral apposition rate without altered body weight or calcium homeostatic hormone levels. A 20% increase in trabecular bone volume in transgenic vertebrae was also observed, unexpectedly associated with a 30% reduction in resorption surface rather than greater bone formation. These findings indicate anabolic vitamin D activity in bone and identify a previously unknown pathway from mature osteoblastic cells to inhibit osteoclastic bone resorption, counterbalancing the known stimulatory action through immature osteoblastic cells. A therapeutic approach that both stimulates cortical anabolic and inhibits trabecular resorptive pathways would be ideal for treatment of osteoporosis and other osteopenic disorders.
|Authors||Gardiner, E. M.;Baldock, P. A.;Thomas, G. P.;Sims, N. A.;Henderson, N. K.;Hollis, B.;White, C. P.;Sunn, K. L.;Morrison, N. A.;Walsh, W. R.;Eisman, J. A. :|
|Responsible Garvan Author|
|Publisher Name||FASEB JOURNAL|
|URL link to publisher's version||http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11023975|