Monday, 27 August 2007

Doctors latching on to leeches

HOW the worm turns – or in this case leeches.
The reviled creature is having a revival in the medical world, after being ousted by antibiotics in the first half of last century.
Now they are back and science is leeching from the leeches.
Research has isolated at least 115 bioactive ingredients from the leech, Hirudo medicinalis, and its almost identical cousin H. verbena. There’s been a mix up in the lab as to which is which and it turns out scientists in some parts of the world, including the United States, may have been testing H. verbena, when they thought it was the other species.
Just who’s who in the leech world, doesn’t stop the slimy creature from offering hope and healing for people everywhere.
Today, leeches are being used directly for pain relief; to help stimulate blood flow when limbs have been reattached; and have been tested as a treatment for patients with lower leg ulcers caused by varicose veins.
Scientists have also extracted hirudin, a peptide or protein found in the salivary glands of the medicinal leech. This is a powerful anticoagulant or blood thinner, which stops or breaks down clotting.
It saved an American man’s life last month.
Daryl Vinson’s heart was only working at 10%, and the Los Angeles man’s future looked grim unless he had a new organ. A donor was found, but doctors faced a major hurdle.
The former air traffic controller was allergic to the mainstream blood thinner heparin, an important drug needed in transplant surgery.
In a do-or-die move, the transplant team from Cedars-Sinai Medical Centre in LA created a substitute anticoagulant using a synthetic form of the leech saliva protein. The resulting drug, bivalirudin, was used, successfully, and Vinson got his new heart in an uncomplicated three-hour operation on July 25.
Leeches have also been used to help save a Nelson fisherman’s fingers. The man had four fingers of his right hand amputated during an accident on board a trawler at Farewell Spit on July 8.
He was flown to Hutt Hospital where plastic surgeons Chris Adams and Charles Davis reattached three of his fingers. They couldn’t save his little finger because it was too badly crushed.
To help with the recovery, one leech after another was put on the end of the man’s ring finger to improve blood flow.
Following surgery there can be a problem with circulation, which prevent sufficient blood and nutrients getting to the reattached body part. But a leech can fix that problem by sucking out dead blood cells and secreting its saliva, containing anti-clotting properties.
The leeches are grown in laboratories so they are considered to be medically clean.
Doctors may look at employing them for treating ulcers, because a study in India has shown great success in treating these long-lasting wounds.
The study, documented in the Indian Journal of Medical Research, looked at 20 men with a mean age of 43 years, who had varying degrees of inflammation and swelling caused by venous ulcers. These are wounds caused by improper functioning of valves in the veins of the lower legs.
None of the patients had diabetes, anaemia or any other illness.
The men had between one and four leeches placed around the ulcer area during a session. The number of applications of leeches varied from 2 to 20, depending on the severity of the wound and the oedema (swelling).
Results from the study were startling.
“Leech therapy effectively decreased oedema and limb girth in 95% of patients, decreased hyperpigmentation (tissue darkened by inflammation) in 75% of patients and resulted in ulcer healing in all the patients, probably by the sucking up of venous blood leading to venous decongestion,” the doctors reported.
And people suffering from arthritis pain can also take heed.
A team of German doctors from the Essen-Mite Clinic in Essen conducted a pilot study involving 16 osteoarthritis patients, who had knee pain for more than six months.
As well as adding exercise, physiotherapy, relaxation therapy and dietary changes to their treatment regime, 10 of the subjects received leech treatment for the pain.
This involved placing four medicinal leeches on the inflamed knee and leaving them for 80 minutes. The other six patients were given conventional pain treatment.
The researchers recorded pain levels three days prior to starting pain treatment and 28 days after treatment had finished.
Once again, the outcome was nothing short of miraculous.
Not only did the leech therapy give the sufferers significant pain relief within 24 hours – it lasted for four weeks without side effects or infections.
In contrast, those who received conventional drug treatment reported no relief from pain.
The German researchers explained that the relief was due to the anaesthetic properties of that sensational saliva, with might contain morphine-like substance and anti-inflammatory enzymes able to penetrate deep into the joints.
Meanwhile, the Beth Israel Medical Centre in New York has begun offering leech therapy to patients with osteoarthritis in their knees.
Sometimes humans are slow learners – or simply think everything from the past is passed its use-by date.
Leeches, you see were first used for medicinal purposes back in 2000BC.
It’s heartening to see we’re finally catching on.

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