Titanium Debris from Artificial Joints May Trigger Painful Inflammation

Newswise — NEWARK, N.J. -- Many people with painful, creaky knees and hips find relief after replacing their bad joints with new artificial joints made from titanium. But some of these people develop painful inflammation that can lead to bone destruction and loosening of the new joint. A new study led by researchers at the University of Medicine and Dentistry of New Jersey and published by the Journal of Immunology suggests that tiny titanium particles that flake away from the artificial joints through normal wear and tear may play a direct role in that inflammation.

Prior studies have suggested that inflammation is caused by bits of bacteria that stick to dislodged titanium particles and activate an immune response. But Pankaj Mishra in the laboratory of William Gause in the Department of Medicine and the Center for Immunity and Inflammation, in collaboration with Joseph Benevenia in the Department of Orthopedics, at UMDNJ-New Jersey Medical School now finds that titanium particles themselves trigger inflammation in mice.

The type of inflammatory response that ensued when titanium particles were introduced—known as a Th2 response—is typically associated with allergic responses and parasitic worm infections and results in the generation of immune cells called alternatively activated macrophages (AAMs). The immune system thus responds to these “inert” micron-sized particles as if they were allergens or invading multicellular parasites. The potential effects of a Th2 response in the joint are not completely clear, but there is increasing evidence that AAMs contribute to bone destruction in prosthesis recipients and in patients with certain type of arthritis.

Journalists who wish to interview the researchers are invited to contact Rob Forman, UMDNJ Chief of News Services, at 973 972 7276 or [email protected] .

The University of Medicine and Dentistry of New Jersey (UMDNJ) is the nation's largest free-standing public health sciences university with more than 6,000 students attending the state's three medical schools, its only dental school, a graduate school of biomedical sciences, a school of health related professions, a school of nursing and its only school of public health on five campuses. UMDNJ operates University Hospital, a Level I Trauma Center in Newark, and University Behavioral HealthCare, which provides a continuum of healthcare services with multiple locations throughout the state.