Preface [Hot topic: Osteoporosis (Executive Editor : Paul Morley)]

The present issue of “Current Pharmaceutical Design” is dedicated to osteoporosis. Osteoporosis is characterized by low bone mass and deterioration of bone leading to increased risk of fracture. It is often called the “silent epidemic” because bone loss occurs without symptoms. One in two women and one in eight men over the age of 50 has osteoporosis, and up to 200 million people worldwide are at risk of osteoporotic fracture. Current anti-resorptive treatments for osteoporosis (estrogen, calcitonin, SERMs, bisphosphonates) can only slow the progression of the disease by inhibiting boneresorbing osteoclasts. Because there are no symptoms, the disease generally goes untreated until a fracture occurs and at that stage current treatments are less effective. Osteoporosis is age-related, and because of increasing life expectancy, the World Health Organization regards osteoporosis as the world's second most important health care problem. The introduction of bone-building drugs to replace lost bone and reduce fracture incidence is one of the most significant unmet medical needs. The issue consists of four reviews. The first two reviews provide recent information on the anti-resorptive bisphosphonates and calcitonin. Dr. Michael Rogers [1] describes the molecular mechanisms by which bisphosphonates act to inhibit osteoclast-mediated bone resorption. Inhibition of a key enzyme in the mevalonate pathway, FPP synthase, can explain the loss of osteoclast bone resorptive activity and the adverse effects of bisphosphonates in the gastrointestinal tract. Drs. Mehta, Malootian and Gilligan [2] then review the actions of calcitonin to preserve bone mineral density and act as an analgesic for bone pain. Novel alternate routes of administration are being investigated to make currently approved anti-resorptive agents more patient friendly. Drs. Lian and Stein [3] review the Runx (AML /Cdfa) family of transcription factors that regulate gene expression at several points in the osteogenic lineage. Novel mechanisms related to Runx regulation of osteoblast differentiation are potential targets for therapeutic agents targeted to bone. The last review by Dr. Katherine Tucker [4], discusses modifiable dietary risk factors for osteoporosis. While the majority of published information focuses on calcium and vitamin D, there has recently been considerable interest in the effects of minerals, vitamins, macronutrients and food components on bone loss and osteoporosis. Prevention of bone loss through diet is clearly very complex and for many factors the evidence is still inconclusive. A much better understanding of the role of each of these factors and the interactions between genetics and nutrition is needed to develop effective patient guidelines for the prevention of bone loss in our aging population. I wish to thank all of the authors for their excellent contributions. References [1] Rogers MJ. New Insights Into the Molecular Mechanisms of Action of Bisphosphonates. Curr Pharm Design 2003; 9(32): 2643-2658. [2] Mehta NM, Malootian A, Gilligan JP. Calcitonin for Osteoporosis and Bone Pain. Curr Pharm Design 2003; 9(32): 2659-2676. [3] Lian JB, Stein GS. Runx2 / Cbfa1: A Multifunctional Regulator of Bone Formation. Curr Pharm Design 2003; 9(32): 2677-2685. [4] Tucker KL. Dietary Intake and Bone Status with Aging. Curr Pharm Design 2003; 9(32): 2687-2704.