Scientists funded in part by the National Institute of Arthritis and Musculoskeletal and Skin Diseases have demonstrated that mouse cells genetically altered with the measles virus nucleocapsid protein (MVNP) bear similarities to those cells found in people with Paget's disease of bone, suggesting a possible connection with the disease's development.

Paget's disease is a disorder of bone remodeling, the process in which old bone is removed (resorption) and new bone is added to the skeleton (formation). In Paget's disease, osteoclasts - the cells that resorb bone - are increased in size and have increased resorption capacity. The increase in bone resorption triggers excessive bone formation, resulting in pain, malformation, and an increased risk of fractures in affected bone. This happens in very specific areas of the body.

Noriyoshi Kurihara, Ph.D., of the University of Pittsburgh, and a team of investigators led by David Roodman, M.D., Ph.D., used genetic engineering techniques to create a strain of mice in which the measles viral protein is produced in osteoclasts. These transgenic mice developed osteoclasts that were larger and formed more readily, as in people with Paget's disease. Additionally, the mice acquired skeletal malformations in specific sites that resembled pagetic bone. Also of interest is the fact that pagetic changes were only observed in the oldest mice; in humans, Paget's disease is more common in older age groups.

Paget's disease is the second most common bone disease (next to osteoporosis), affecting more than two million people in the United States. Its cause is not fully known, although available evidence suggests that viral and genetic factors may play a role. Although Kurihara and his colleagues do not conclude that measles virus can cause Paget's disease, their work provides the strongest evidence to date that measles virus or other commonly encountered viruses can be an important factor in the development of the disease.

Dr. Kurihara's research was also funded by the National Cancer Institute and the U.S. Army Medical Research and Material Command.

The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment, and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress in these diseases. For more information about NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS Web site at www.niams.nih.gov.

# # #

Kurihara N et al. Expression of measles virus nucleocapsid protein in osteoclasts induces Paget's disease-like bone lesions in mice. J Bone Miner Res.2006;21(3)446-55.