How Does Rheumatoid Arthritis Attack the Whole Body?

One of the mysteries in the understanding of aengineered not to reject tissue from a different
complicated disease like rheumatoid arthritis is... howspecies. The implantations were done in the flanks.
does it attack so many joints? What causes it toOn one flank, the mice received healthy, normal human
spread?cartilage; on the other, they received cartilage loaded
Rheumatoid arthritis is a chronic, systemic, autoimmunewith human RASFs.
condition that usually starts in a single joint but thenA control group of mice who received normal healthy
spreads to involve multiple joints. The hallmark of thecartilage in both flanks showed minimal damage, as did
disease is its symmetrical joint involvement. Also,mice that received implants of fibroblasts from patients
because internal organs may be affected, it is awith osteoarthritis.
disease that carries with it substantial morbidityAnother striking discovery occurred when the
(complications) as well as mortality (death).researchers sacrificed the mice and examined the
Rheumatoid arthritis is very different from the otherspleens. The mice which developed rheumatoid arthritis
common form of arthritis, osteoarthritis, which ishad spleens packed with RASFs. The spleen is the
basically a wear and tear problem localized tomajor organ responsible for filtering blood. The fact
weight-bearing joints. Osteoarthritis does not producethat RASFs are found in such abundance in the
the destructive changes that are characteristic ofspleens of the rheumatoid arthritis mice provides
rheumatoid disease.strong evidence that RASFs travel through the blood
Recent research has provided tantalizing evidence asstream to do their damage rather than just secrete
to how rheumatoid arthritis spreads.chemicals that go into the blood stream.
Researchers at Justus-Liebig University in BadApparently RASFs can travel via the blood stream
Nauheim, Germany recently published the results ofand then leave by crawling through the spaces
their work in Nature Medicine demonstrating the criticalbetween cells that form the lining of the blood vessels
role of rheumatoid arthritis synovial fibroblasts (RASFs)to invade other joints and other organ systems.
in the spread of the disease.When the researchers look at the joints of the
Fibroblasts are a type of cell that is primarily involved insacrificed mice, they didn't find RASFs. They
the wound healing process. They are responsible forhypothesized that it takes time for the RASFs to
the laying down of connective tissue. However, whentravel to other joints and can only enter cartilage if
turned on in a particular fashion, they morph from Dr.there is already some minor damage. This would
Jeckyll into Mr Hyde.explain why it often takes many months for
These "turned-on" fibroblasts, now known asrheumatoid arthritis to spread.
"rheumatoid arthritis synovial fibroblasts", are present inThe scientific findings have therapeutic implications
abundance in the synovium- the lining of the joint.since treatments designed to prevent RASFs from
These RASFs become very destructive and are feltentering the bloodstream, traveling through the blood
to be one of the major culprits responsible for thestream, or leaving the blood stream to attack healthy
damage to cartilage found in rheumatoid arthritis.tissue could potentially prevent the spread of
To elucidate the mechanism by which RASFs couldrheumatoid arthritis.
spread arthritis from joint to joint, lead author Elena[Editor's note: I personally think this is one of the most
Neumann and her colleagues took human cartilage andexciting bits of news in a long time and the authors
implanted it under the skin of mice geneticallyshould be commended for such fine work.