New lab mouse to help study increased risk of autoimmune inflammatory diseases in women

Researchers at the Mayo Clinic have produced a new lab mouse that offers promise for studying increased risk of auto-immune inflammatory diseases in women. They claim that the new breed of transgenic mice produced by them shows autoimmune responses similar to human RA patients, and increased incidence of the disease in females. Rheumatoid arthritis (RA) is a complex and confounding autoimmune disease characterised by chronic synovial tissue inflammation, increasing erosions of cartilage and bone, and eventual destruction of joints. It is associated with a variety of genetic and environmental factors and known to strike women about three times as frequently as men.

Until now, a major obstacle to investigating this clear sex bias has been the lack of a laboratory rat or mouse that mimics human RA. The researchers say that their humanised mouse model may be valuable for not only studying sex differences in RA, but also for understanding why women are particularly vulnerable to autoimmunity, and for developing future therapeutic strategies.hey found that of the transgenic mice that developed arthritis, all produced rheumatoid factors and anti-CCP autoantibodies strikingly similar to humans, which included auto antibodies to type II collagen (CII), increased expression of class II molecules T cells, and production of proinflammatory cytokines. Further, female mice developed arthritis at a higher rate than the male mice, by a ratio greater than 3 to 1, and exhibited all the disease hallmarks at higher levels. Dr. Maurizio Cutolo, a researcher with the Department of Rheumatology, the University of Genoa, Italy, believes that the new findings may shed light on the role of oestrogen and androgen in the disease. "Sex hormone balance is a crucial factor in the regulation of immune and inflammatory responses. Modulation of this balance should represent part of advanced biologic treatments for RA. Sharing the sex hormone effects of the human disease, the new humanized mouse may provide a better model with which to study the pathogenesis and treatment of arthritis," Dr. Cutolo notes.(Source: Arthritis and Rheumatism : Mayo Clinic: January 2007.)