Strontium ranelate inhibits bone resorption while maintaining bone formation in alveolar bone in monkeys (Macaca fascicularis)

Strontium ranelate (S12911) has previously been shown to stimulate bone for mation and inhibit bone resorption in rats. To determine whether strontium ranelate affects normal bone remodeling, we studied the effect of strontium ranelate on alveolar bone in monkeys. Strontium ranelate, at dosages of 10 0, 275, and 750 mg/kg per day, or vehicle, were given by gavage to 31 norma l adult monkeys (Macaca fascicularis) (15 males, 16 females), aged 3-4 year s. Treatment for 6 months with strontium ranelate resulted in an increase i n plasma strontium concentration. Histomorphometric analyses of indices of bone formation and resorption were determined in standardized areas of alve olar bone. Treatment with strontium ranelate decreased the histomorphometri c indices of bone resorption (osteoclast surface and number) with a maximal significant effect at the highest dose tested. In contrast to this inhibit ory effect on bone resorption, strontium ranelate maintained bone formation . Although the amount of osteoid tended to increase, strontium ranelate, ev en at the highest dose, had no deleterious effect on bone mineralization, a s evaluated by mineral apposition rate and osteoid thickness. These finding s show that strontium ranelate decreases indices of bone resorption while m aintaining bone formation in the alveolar bone in monkeys. (C) 2001 by Else vier Science Inc. All rights reserved.