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University of Iowa study shows hormones linked to juvenile rheumatoid arthritis

IOWA CITY, Iowa -- University of Iowa researchers have demonstrated for the first time a correlation between juvenile rheumatoid arthritis (JRA) and low hormone levels in synovial fluid and serum.

While further investigation is needed to determine how the hormones affect the disease, these findings show promise for developing possible hormone treatment strategies to help fight JRA, said Mary J.C. Hendrix, Ph.D., UI professor and head of anatomy and cell biology.

"Everybody looks to other reasons for arthritis," Hendrix said. "People never really think of hormones as affecting this disease, but our research shows that it does. Knowing what our study has uncovered opens the door for looking at new ways to treat the condition."

The UI findings are included in the current issue of Clinical and Experimental Rheumatology.

Rheumatoid arthritis (RA) is an often debilitating condition that affects the connective tissue of joints. It is a chronic and progressive disease that erodes the articular cartilage, often leading to deformities and disabilities. JRA is the most common rheumatic disease in children and affects mostly girls.

Other researchers have conducted studies looking at how sex hormones influence RA. There also have been a limited number of investigations into the hormonal status of children with arthritis. However, the past work has looked mostly at the serum levels, and not the amount of hormone in the synovial fluid, Hendrix noted. Synovial fluid is lubricating joint oil. Serum is the fluid portion of the blood.

Zhila Ellis, Ph.D., an assistant research scientist in anatomy and cell biology who works in Hendrix's lab, led the UI investigation. In collaboration with St. Louis University's Terry L. Moore, M.D., the UI researchers examined the synovial fluid and serum from 21 JRA patients -- half of whom were between ages 5 and 12, the other half of whom were between 15 and 18 years old. Specifically, the researchers wanted to analyze the serum and synovial fluid for levels of testosterone, as well as the hormones dehydroepiandresterone (DHEA) and its sulphated conjugate DHEA-S, progesterone and 17 beta-estradiol. The investigators then compared the hormone levels in the synovial fluid and serum to the levels found in the serum of a control group of subjects. The researchers did not look at the synovial fluid from the control group because it would be almost impossible to sample the small amount found in non-inflamed joints.

The UI data showed reduced levels of DHEA-S and testosterone in the synovial fluid and serum of JRA patients. In addition, the ratio of DHEA/DHEA-S in both synovial fluid and serum was much higher than that of the corresponding control serum, thus indicating the potential importance of hormonal imbalances in the JRA disease process.

Researchers in Hendrix's lab are continuing with their JRA work. Their on-going studies focus on the character of hormone receptors with respect to their role in the disease progression.

12/8/98