The hormone leptin may play an important role in the development of osteoarthritis by regulating cartilage-producing cells, French researchers report.
The hormone leptin may play an important role in the development of osteoarthritis by regulating cartilage-producing cells, French researchers report. Leptin, produced by fat cells, normally regulates food intake and energy expenditure by suppressing appetite as levels increase. Leptin levels are often high in overweight people, who may be resistant to the appetite-suppressing effects of the hormone. It also affects a variety of physiological and immune processes, the authors of an article in the journal Arthritis and Rheumatism explain, and leptin receptors have been found in normal human cartilage. Dr. Helene Dumond and colleagues from CNRS, Vandroeuvre les Nancy, France, measured leptin levels in joint fluid from patients with osteoarthritis. “This study is the first to show that leptin was detected in (joint) fluid obtained from osteoarthritis patients,” the authors report. Leptin levels in synovial fluid were higher in heavier patients. The team found that leptin was abnormally high in osteoarthritic cartilage-producing cells, the report indicates, and the proportion of cells producing leptin paralleled the severity of osteoarthritis. When the researchers injected leptin into the knee joints of rats, it markedly increased the levels of several inflammatory compounds. “Taken together,” they conclude, “these findings indicate that leptin may play an important role in the pathogenesis of osteoarthritis.” Osteoarthritis is known to be a particular problem for overweight people, and this has been attributed to excessive wear and tear on weightbearing joints. The latest findings suggest that, in fact, leptin may explain the link between being heavy and the risk of developing osteoarthritis.(Source: MEDline Plus, Arthritis and Rheumatism, Reuters November 2003)