Green
Tea Helps Arthritis
New University Study Finds
Date: 1 May 07
By A new study from the University of Michigan Health
System suggests that a compound in green tea may provide
therapeutic benefits to people with rheumatoid arthritis.
The study, presented April 29 at the Experimental Biology
2007 in Washington, D.C., looks at a potent
anti-inflammatory compound derived from green tea.
Researchers found that the compound called
epigallocatechin-3-gallate (EGCG) inhibited the production
of several molecules in the immune system that contribute to
 inflammation
and joint damage in people with rheumatoid arthritis.
The compound from green tea also was found to suppress the
inflammatory products in the connective tissue of people
with rheumatoid arthritis.
"Our research is a very promising step in the search for
therapies for the joint destruction experienced by people
who have rheumatoid arthritis," says Salah-uddin Ahmed,
Ph.D., lead researcher on the study. Ahmed, a research
investigator with the Division of Rheumatology at the U-M
Health System, was selected to present the research at the
Experimental Biology meeting as the recipient of the Young
Scientist Travel Award, given by the American Society for
Pharmacology and Experimental Therapeutics. This study was
also selected by the American Society for Nutrition to be
featured in a press release.
To conduct the research, the scientists isolated cells
called synovial fibroblasts from the joints of patients with
rheumatoid arthritis. These fibroblasts cells that form a
lining of the tissue surrounding the capsule of the joints
then were cultured in a growth medium and incubated with the
green tea compound.
The fibroblasts were then stimulated with pro-inflammatory
cytokine compound, a protein of the immune system known to
play an important role in causing joint destruction in
people with rheumatoid arthritis.
The researchers looked at whether the green tea compound has
the capability to block the activity of two potent
molecules, IL-6 and cyclooxygenase-2 (COX-2), which also are
actively involved in causing bone erosion in the joints of
people with rheumatoid arthritis.
When untreated cells were stimulated with IL-1?, a sequence
of molecular events occurred that resulted in production of
the bone-destructive molecules. But the scientists found
that pre-incubation with EGCG was capable of inhibiting the
production of these molecules. EGCG also inhibited the
production of prostaglandin E2, a hormone-like substance
that causes inflammation in the joints.
The cell signaling pathways that regulate levels of these
immune system molecules under both normal and rheumatoid
arthritis situations are well studied, and the researchers
were able to trace the effects of the green tea compound
infusion to see that it worked by inhibiting these pathways.
Ahmed says that these studies suggest that EGCG or molecules
that could be derived synthetically from the EGCG found in
green tea may be of therapeutic value by inhibiting the
joint destruction in rheumatoid arthritis.
Previously, Ahmed and other researchers made another
promising finding when EGCG-pretreated synovial fibroblasts
were stimulated with the cytokine IL-1? to study the
protective effect of this green tea compound. Compared to
untreated synovial fibroblasts, the cells treated with EGCG
markedly blocked the ability of IL-1? to produce the
proteins and enzymes that infiltrate the joints of persons
with rheumatoid arthritis and cause cartilage degradation.
The laboratory now is focused on the inhibitory role of EGCG
in gene expression. The scientists plan to test EGCG in
animal models of rheumatoid arthritis to see if it provides
similar therapeutic or preventive effects. Ahmed believes
that the outcome of these studies will form a strong
foundation for future testing of green tea compound in
humans with rheumatoid arthritis. |
