TORONTO, Canada, June 6 /PRNewswire/ --
-- The Increase of OPG Expression Explains the Uncoupling Effect of Protelos(R) on Bone Metabolism
Exciting new data presented at the World Congress on Osteoporosis further the understanding of the unique dual mode of action of the anti-osteoporotic agent Protelos(R) (strontium ranelate)(1), which makes it totally different from the other existing treatments available.
Results from a study on osteoblasts (cells responsible for creating the bone matrix) confirm that Protelos(R) stimulates bone formation and also decreases bone resorption. Protelos(R) was found to stimulate the expression of osteoprotegerin (OPG), a protein that inhibits osteoclast (cells responsible for resorbing bone) formation and activity. OPG is produced naturally in osteoblasts.
Protelos(R) reduces both vertebral and hip fractures in postmenopausal women and is an effective treatment for osteoporosis. Previous studies have shown that Protelos(R) increases the bone formation and decreases bone resorption and thus rebalances bone turnover in favor of bone formation. The study has, for the first time, demonstrated the uncoupling effect of Protelos(R) at the cellular level. By acting directly on osteoblasts, Protelos(R) increases OPG mRNA expression leading to a decrease in bone resorption through a "decoupling" between osteoclasts and osteoblasts. These data therefore explain for the first time Protelos(R)' unique mode of action at a cellular level.
Effect of Protelos(R) on osteoblasts
The in vitro study evaluated the effect of Protelos(R) on the proliferation of osteoblasts and OPG expression in human preosteoblastic cells. Protelos(R) significantly and dose-dependently stimulates the proliferation of osteoblasts after treatment. In addition, Protelos(R) significantly and dose dependently increases the expression of OPG mRNA after treatment, thereby inhibiting bone resorption.
Effect of Protelos(R) on bone quality
According to new three-dimensional (3D) bone biopsy data from Yebin Jiang, MD, PhD and his colleagues from the University of California, San Francisco, USA, Protelos(R) has beneficial effects on the 3D bone microstructure thereby improving bone mechanical competence and bone quality(2).
"Bone quality in terms of fracture resistance is a function of the bone's apparent density and three-dimension distribution," points out Dr Jiang. "The action of Protelos(R) on 3D trabecular and cortical microstructure helps explain why Protelos(R) treatment reduces the risk of vertebral and hip fractures."
Dr Jiang and colleagues studied transiliac bone biopsies from 41 postmenopausal women participating in the SOTI (Spinal Osteoporosis Therapeutic Intervention)(3) and TROPOS (Treatment Of Peripheral Osteoporosis)(4) studies. The biopsies were from women treated with either Protelos(R) 2g/day (n=20) or placebo (n=21). Compared to placebo, Protelos(R) treatment significantly stimulates 3D trabecular and cortical bone formation leading to an improvement of bone microstructure.
Protelos(R) has sustained efficacy against both vertebral and hip fractures in postmenopausal osteoporotic women.(5) In addition, it is well tolerated and easy to use for patients.(6)
Protelos(R) is licensed in Europe for the treatment of postmenopausal osteoporosis to reduce the risk of vertebral and hip fractures in patients with or without a previous history of fractures. It is now available in 57 countries worldwide, including France, Germany, the UK, Spain, and Italy.
References:
1. Brennan Tc et al. Calcif Tissue Int. 2006;78(suppl 1):S129 (P356).
2. Jiang Yebin, Oral communication, World Congress on Osteoporosis 2006,
Toronto, Canada.
3. Meunier PJ, Roux C, Seeman E, et al. N Engl J Med. 2004;350:459-468.
4. Reginster JY, Seeman E, De Vernejoul MC, et al. J Clin Endocrinol
Metab. 2005;90:2816-2822.
5. Reginster JY. Osteoporos Int. 2006;17:S11-S12 (OC31).
6. Protelos(R) European Summary of Product Characteristics.
For further information or to arrange an interview with Dr Jiang, please contact: Moira Gitsham, tel +33-5-46-00-08-20, mobile: +33-6-20-74-01-92, email: moira.gitsham@toniclc.com; Lola Bhadmus, tel +44(0)207-798-9900, email: lola.bhadmus@toniclc.com
