Obesity Hormone May Affect Osteoarthritis
Leptin May Play Key Role in Causing Joint Disease
Nov. 4, 2003 -- A hormone commonly associated with obesity may also play a role in the disease osteoarthritis.
New research shows that the hormone leptin is found in higher levels in diseased joint cartilage samples taken from people with osteoarthritis of the knee compared with normal cartilage. In addition, the amount of leptin found in the cartilage also corresponded with the level of damage found in the joint.
Osteoarthritis is one of the most common forms of arthritis and frequently affects older people. It occurs when the cartilage that connects the joints begins to break down until the bones eventually rub against each other.
Researchers say the findings may help explain why obesity increases the risk of developing the potentially disabling disease. The exact cause of osteoarthritis is not known, but the risk of the developing the disease rises as a person's body mass index (BMI, a indicator of weight in relationship to height used to measure obesity) increases.
First Study to Link Leptin and Osteoporosis
Researchers say it's the first study to show that leptin is found in joint fluid samples taken from people with osteoarthritis.
In the study, researchers took samples from the diseased joint cartilage of osteoarthritis patients who were undergoing knee replacement or other knee surgery and compared them to normal cartilage samples. They found that not only did the diseased samples have higher than normal levels of leptin, but the leptin levels and distribution were also related to the degree of cartilage destruction found.
In addition, animal testing shows that leptin stimulated growth factors associated with the progression of osteoarthritis.
The results appear in the November issue of Arthritis & Rheumatism.
Researchers suspect that leptin may penetrate into the cartilage of people with osteoarthritis and target genes involved in stimulating the progression of the disease. They say more research is needed to identify the mechanisms involved in this process in order to better understand the causes of osteoporosis.