Long-Term Silicone Implants Increase Susceptibility To Autoimmune Disease In Mice
Long-Term Silicone Implants Increase Susceptibility To Autoimmune Disease In Mice WESTPORT, Aug 13 (Reuters Health) -
Long-term silicone implantation results in the production of autoantibodies and an increase in the incidence of experimentally induced arthritis, according to the results of a study in mice published in the August issue of the Annals of Rheumatic Diseases. Dr. Paul H. Wooley and colleagues from the Wayne State University Medical School in Detroit, Michigan, explain that silicone implants in humans has been associated with autoimmune connective tissue diseases. They note, however, that previous studies in mice have failed to show that short-term silicone exposure increases the incidence or severity of experimentally-induced rheumatoid arthritis. Their aim in the present study was to determine the effects of long-term silicone implantation on type II collagen-induced arthritis. The authors implanted mice with silicone elastomers, silicone gel or silicone oil, or with a saline control. After 9 months they immunized the animals with type II collagen. Dr. Wooley's team observed a 90% incidence of arthritis in mice implanted with silicone elastomers, compared with a 30% incidence in saline-treated mice. They also observed that "[t]he long-term implantation of silicone gel or oil also increased the incidence of disease," but the "...increases did not reach statistical significance." The investigators also found that both silicone elastomer and gel induced the production of antibodies directed against silicone-bound proteins, including type I collagen. "This result is consistent with two studies that report autoantibodies to type I collagen in women with silicone implants," they note. The study group cautions that the conclusions of their study in relation to patients with silicone implants should be interpreted with great care. In an interview with Reuters Health, Dr. Wooley pointed out that silicone implantation in mice results in the production of a number of autoantibodies that are similar to those seen in human autoimmune diseases, such as lupus. "The production of silicone-induced autoantibodies probably has no pathological consequences in most cases, but autoimmune diseases may develop in a small number of women in whom the silicone implant is left long enough," he added. "It is not yet possible to identify women who may be susceptible to silicon-induced autoimmune disease, or to identify [who] would have developed autoimmune diseases regardless of the presence of the silicone implants," Dr. Wooley added. Ann Rheum Dis 1999;58:503-509.