Leeches and arthritis research
g.read at niwa.cri.nz
Wed Sep 16 18:25:36 EST 1998
The following is from the news service of the RSNZ
<http://www.rsnz.govt.nz/cgi-bin/new_news.pl> and copyright the New
Zealand Press Association.
Geoff Read <g.read at niwa.cri.nz>
Leeches may hold key to beating rheumatoid arthritis
Auckland, Sept 15 1998 - The humble leech could hold vital clues for the
treatment of rheumatoid arthritis, a disease which afflicts up to 225,000
New Zealanders every year.
Scientists at Auckland University's school of biology have discovered that
a chemical found in European leeches may slow down the growth of cells in
joints affected by rheumatoid arthritis.
The team hope its research can tell them how the leech-based chemical
reduces arthritis so it can be turned into a drug to beat the crippling
The European leech -- hirudo medicinalis -- has been used for a century for
its medical properties and more recently for treating accident victims
whose limbs have been severed or crushed.
Thanks to anti-coagulants found in its salivary glands, the European leech
has also been found to benefit heart patients by reducing the risk of blood
Doctors here have already been using a New Zealand leech variety called
richardsonianus mauianus to restore blood flow to severed limbs.
Auckland University biochemist Dr Ken Scott said he was now examining the
Kiwi variety to establish whether it had other healing properties similar
to its European cousin.
He has been awarded a grant by the Auckland Medical Research Foundation to
carry out the project which involves extracting the anti-clotting compound
from leeches' bodies.
"We were already looking at a particular compound that comes from the
European leech called hirudin. Hirudin is used by the leech when it is
feeding to prevent its host's blood from clotting," Dr Scott said.
"The chemical is now made artificially in large quantities by genetic
engineering and has already been shown to be very effective for treating
heart attack victims to reduce the risk of blood clots.
"It has also been shown to inhibit the growth of certain tumour cells. In
our own study we discovered it can also block the growth of cells found in
"If we can establish how this process works we believe that this leech
compound could offer a new way of treating rheumatoid arthritis and also
applications for other medical conditions," he said.
Dr Scott said his team has been trying to work out whether hirudin binds to
and inhibits the action of an enzyme called thrombin which is an important
stage in the blood's clotting process.
The leeches are grown in Northland and cost around $10 each. They were
recently used by surgeons to reattach the lip of a Taranaki toddler after
it was bitten off in a dog attack.
Dr Scott also said colleagues in America were carrying out tests on the
European leech to find out how it could slow the rate of growth in tumours.
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