Research on Arthritis.
Last updated Tuesday, January 04, 2005
Recent research
Today scientists are looking at four broad areas of research: causes, treatments, education, and prevention. Much of the research discussed here involves early findings. Some of these results need to be repeated in other studies before they are accepted by most scientists.Causes The causes of most forms of arthritis are unknown. Therefore,
doctors try to treat symptoms rather than attacking the roots of the
problem. This is why so much research focuses on how the healthy body
works and what goes wrong in arthritis. By understanding what causes
arthritis, researchers hope to design better methods for diagnosing,
treating and even preventing some arthritis-related diseases.
Research into the causes of arthritis became fast-paced in the 1980s
because of the development of new techniques in molecular biology.
Molecular biology is the science that studies how molecules in our
cells (the smallest parts of our body) work. Research in this area has
greatly advanced our understanding of how our body's defense system
works and what happens when it fails.
Research into causes of arthritis looks at how four factors work
alone and together to produce disease. These four factors include how
the body itself contributes to the disease process and the roles
heredity, infections and the environment play.
Body
Researchers are trying to understand how the body itself contributes
to the disease process. They are studying how the body works and what
changes accompany various types of arthritis. For instance, researchers
are trying to understand how the parts of the joint work and what
happens when they fail. One major part of a joint they are examining is
cartilage.
Cartilage is a resilient material that covers the ends of bones and
prevents them from rubbing together where they meet in a joint. It
serves as nature's shock absorber by changing shape as the joint moves.
When you put weight on your knee, the cartilage flattens. When you
relax, the cartilage expands.
Researchers have discovered that early in osteoarthritis
chemical changes result in the loss of two types of fibers,
proteoglycans and collagen, which help give cartilage its resiliency.
At the same time, enzymes called proteases--which normally destroy old
cartilage so it can be replaced by new growth--begin destroying
cartilage much faster than it can be replaced. This process seems to
happen faster in some people and studies are under way to find out why.
Another key question is how the immune system protects the body from
the destruction of inflammatory types of arthritis. In the immune
system, there are specialized cells and a special family of proteins,
called antibodies, as well as other chemical substances that help
control and modify how the system responds. Among these chemical
substances are interleukins and gamma interferon, which are made by the
immune cells. These substances appear to be involved with certain types
of arthritis.
Inflammation, which involves swelling, redness and heat, is one of
the immune system's responses in several types of arthritis. Studies
have found that high levels of a group of chemicals, called
prostaglandins, result in inflammation. Researchers have found, for
instance, that aspirin interferes with the production of
prostaglandins.
Heredity
Scientists are researching how heredity increases risk for certain
types of arthritis. Heredity may help explain why some kinds of
arthritis, such as ankylosing spondylitis and rheumatoid arthritis,
strike people of various sexes and races differently. Some genes may
carry a set of instructions that increases the chances for developing
certain types of arthritis.
For instance, people with HLA-B27, a genetic marker, are more likely
than the general population to develop ankylosing spondylitis and
several other related types of arthritis. Several North American Indian
tribes have higher levels of HLA-B27 and more ankylosing spondylitis.
Some specific genes have already been identified for ankylosing spondylitis, gout, psoriatic arthritis, rheumatoid arthritis and systemic lupus erythematosus.
Infection
A third area of research into causes of arthritis looks at how
infections set off or slow down the immune system's response. It seems
that in some forms of arthritis, infections combine with a faulty gene
to set off one or more malfunctions in the immune system. This causes
the immune system to make errors. Instead of protecting healthy parts
of the joints and other sites in the body, the system turns against
itself. This condition is called autoimmunity.
Autoimmunity results from the actions of substances called T cells
or autoantibodies. T cells are specialized white blood cells, which
help distinguish between the body's own tissues and foreign invaders.
Antibodies are specialized white blood cells that protect the body by
attacking and destroying foreign invaders. For reasons not yet clearly
understood, in autoimmunity antibodies recognize healthy parts of the
body as foreign and attack them. Researchers call these antibodies that
attack healthy parts of the body autoantibodles.
Scientists are now studying why certain people make T cells and
autoantibodies, which cannot distinguish healthy parts of the body from
foreign invaders, and whether they can cause disease symptoms.
Autoantibodies may also serve as a kind of name tag to indicate people
who are more likely to develop certain kinds of arthritis.
Scientists think that bacteria and viruses may help trigger
malfunctions in the immune system. They have already linked bacteria to
infectious arthritis, Reiter's syndrome and Lyme disease.
Researchers are now looking at how certain viruses, such as the
Epstein-Barr virus of infectious mononucleosis or the HIV virus of
AIDS, may trigger other types of arthritis.
Researchers are also trying to understand a process called molecular
mimicry. In this process, substances in the body look like or mimic an
invading virus and thus set off destruction of healthy parts of the
joint.
Environment
The fourth factor in research into the causes of arthritis,
environment, is getting renewed attention. Here, scientists are looking
at how where and how you live influence your risk for certain types of
arthritis.
For instance, researchers have long been intrigued by variations in disease patterns among countries, especially in rheumatoid arthritis.
Scientists are now looking at remains of Indians in North America to
see if rheumatoid arthritis was a new disease, a mutation from another
disease, or a disease that spread during colonization from the New
World to the Old.
Historical records and skeletal remains suggest that rheumatoid
arthritis appeared in Europe as late as 300 years ago. New findings in
North American Indian skeletons from 1200 years ago suggest that
rheumatoid arthritis is a New World disease that spread to the Old
World. Scientists are now looking for what caused the disease to
spread. The answer may help us understand what causes rheumatoid
arthritis.
Several studies indicate that certain injuries can lead to
arthritis. Football players, who have suffered twisting injuries to the
knees, have an increased likelihood of getting osteoarthritis
of the knees. Early findings suggest that certain repeated movements
done over a long period of time by some workers may injure a joint.
More research is needed in both these areas before we can understand
how they may be involved in arthritis.
Researchers are looking at how the body's defenses, heredity,
infections and environment or lifestyle interact to cause certain types
of arthritis. Treatments Many tests
have been developed to aid doctors in diagnosing various types of
arthritis. In addition, research has helped doctors look for patterns
of symptoms associated with certain types of arthritis. For instance,
in fibrositis doctors look for chronic muscle aches in more than three
sites, sleep disturbances, acutely painful tender points in certain
parts of the body and the lack of any underlying illness. Researchers
are now looking at new findings on decreased blood flow, decreased
endurance and cold sensitivity.
New drugs have been developed to slow down the immune system's response in rheumatoid arthritis and lupus.
Some of these drugs are borrowed from treatments for cancer and
transplant surgery. In arthritis, these drugs are used at lower doses
but still have many unwanted side effects. Researchers are currently
testing whether changing the way drugs are given or combining two drugs
at lower doses works and has less side effects. Early results from some
combinations of specific drugs suggests this combination therapy may
help reduce side effects.
Recent research on nonsteroidal antiinflammatory drugs
has concentrated on reducing their side effects to the stomach. These
drugs, such as ibuprofen, are widely used to stop pain and inflammation
in arthritis. However, some people cannot take them because they cause
stomach problems. Scientists have been looking at anti-ulcer drugs and
other ways to reduce the impact of chronic use of nonsteroidal
anti-inflammatory drugs on the stomach.
How diet
affects the response of the immune system in arthritis is a central
question in a number of diet-related research studies. For instance,
dietary factors can affect the immune system's inflammatory response.
In some studies, there has been a modest lessening of subjective
symptoms. Several researchers have observed that fasting, low
calorie/low protein diets and the fatty acids in fish oils slightly
reduce some symptoms of rheumatoid arthritis. Scientists do not yet
understand why this happens or if certain changes in diet, such as
short-term fasts, help.
Artificial joints have helped many people with arthritis in their
hips, knees or even fingers regain lost movement. They have been
especially helpful in reducing pain and correcting deformity in people
with osteoarthritis, rheumatoid arthritis and ankylosing spondylitis.
Research into treatments is also looking at:
Self-management Researchers are also looking at what people with arthritis can do to help themselves. They have shown that some aerobic exercises,
which are good for the heart, are also safe for the joints. People with
arthritis who did these exercises regularly reported less pain and
fatigue.
Researchers are also studying ways to increase people's feelings of
control, which is called self-efficacy. Studies in education show that
it is not how much people learn but how much they feel in control that
helps them cope with arthritis. Prevention Stopping arthritis before it ever starts or preventing disability
once you have arthritis holds the greatest hope for the future.
Research is just beginning to pick up steam in the area of prevention.
Doctors have long suspected that being overweight puts stress on the
knees. Three recent studies have now confirmed that obesity increases
the risk for developing osteoarthritis of the knees.
Recent studies have looked at what helps keep workers with arthritis
on the job rather than on disability. These studies suggest factors
related to the job rather than to disease severity cause a worker to
stop working. Factors such as the physical demands of the job and the
lack of control over pace or work seem to increase your chances for
disability if you have arthritis. Age and the presence of other health
conditions are also important. Studies now need to be done to see if
changing job-related factors helps keep workers with arthritis
employed. Research in prevention is beginning to identify factors, such
as obesity and work patterns, that increase risk for disease or
disability.
Research in prevention is also looking at diet, injuries, and social support.
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