Rheumatoid arthritis is a diagnosis that covers a wide range of inflammatory joint disease. Current research indicates there are multiple genetic and environmental factors involved in the cause of the disease. Different people also respond differently to the available treatments. Approximately two thirds of patients get good results from the biologic drugs called tumor necrosis factor inhibitors. But these drugs have serious side effects and must be administered by injection. It would be highly desirable to find out which patients can benefit from such drugs before treatment is started. Researchers are studying potential biomarkers in the blood and synovial fluid of rheumatoid arthritis (RA) patients.
From blood bank samples, one study showed that 49 percent of RA patients tested positive for immunoglobulin M rheumatoid factor or anticitrullinated protein antibodies, or both, at a median of 4.5 years before the onset of symptoms. But some patients test positive for these proteins and never develop RA. Thus, there is more to be learned about the process of developing joint inflammation.
One issue that has become clear is the connection between joint inflammation and atherosclerosis. Reference 2 contains a graphic illustration of the similarities between atherosclerotic plaque and rheumatoid arthritis joint. Both are formed from abnormal activity of the mononuclear white blood cells, inflammatory cytokines, and change in properties of the resident cells.
Patients with rheumatoid arthritis have increased risk of cardiovascular disease, including pericarditis, myocarditis, atrioventribular block, ischemic heart disease, carotid artery plaque, multi-vessel coronary artery disease, and coronary atherosclerosis. The risk of heart attack (myocardial infarction) is increased twofold in RA patients.
There is a particular pattern of blood lipids in people who develop rheumatoid arthritis. Both good cholesterol (HDL) and bad cholesterol (LDL) are low, but triglycerides are high. This can often be detected 10 years or more before joint symptoms appear.
When tumor necrosis factor inhibitor drugs are effective for RA, they appear to be protective against cardiovascular disease. In addition, corticosteroids used for RA may have some cardiovascular benefits, even though they have the disadvantages of promoting insulin resistance, weight gain, fluid retention, and high blood pressure. Methotrexate also has mixed results in its effect on cardiovascular health. It decreases inflammation, but also causes depletion of the vitamin folic acid.
Researchers hope to learn more about which patients can benefit from which treatments. There are currently 966 clinical trials listed at clinicaltrials.gov. Check with your doctor to see what the latest results mean for you.
Sources:
1. Verweij CL, “Transcript profiling towards personalised medicine in rheumatoid arthritis”, Neth J med. 2009 Dec; 67(11): 364-71.
2. Full LE et al., “The inextricable link between atherosclerosis and prototypical inflammatory diseases rheumatoid arthritis and systemic lupus erythematosus”, Arthritis Res Ther. 2009; 11(2): 217.
Linda Fugate is a scientist and writer in Austin, Texas. She has a Ph.D. in Physics and an M.S. in Macromolecular Science and Engineering. Her background includes academic and industrial research in materials science. She currently writes song lyrics and health articles.