Cytokines and mediators in physiologic and pathologic bone resorption

Abstract

New England Baptist Bone and Joint Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, U.S.A. INTRODUCTION Peri-implant Bone Remodeling Maintaining healthy bone at the surface of prosthetic implants is vital for the longterm stability of artificial joints. Healthy bone is in a dynamic state continually being lost and replaced through the process of remodeling. Remodeling of bone relies on the integrated activity of the osteoblast (bone forming) and osteoclast (bone resorbing) cells to maintain the balance of bone metabolism (1). An imbalance in bone metabolism due to either excessive resorption or decreased bone formation can result in bone loss. While we have known for well over a decade about the factors, such as the bone morphogenic proteins, which regulate bone formation by osteoblasts, it is only relatively recently that we understand how osteoclasts form and resorb bone. While this review of peri-implant osteolysis will focus on the mediators that regulate osteoclasts it is important to recognize that bone formation by osteoblasts may also be disrupted in this pathology.