STRAIGHT TO THE HEART

Snorting charlie can make your body turn on itself

THE fashion for cocaine may be causing a wave of heart disease among young
people. Besides its known effect of sending coronary arteries into spasm,
the drug also encourages the immune system to turn on healthy cardiac
tissue, researchers in Michigan have discovered.

The work comes as some doctors are complaining that the abuse of the drug is
causing a hidden drain on already stretched hospital resources. They believe
that cocaine is making large numbers of otherwise fit young people-most of
them men-report to emergency departments with chest pains.

The immunological study, led by Benedict Lucchesi of the University of
Michigan in Ann Arbor, suggests that cocaine activates a part of our immune
defences called the complement cascade. This system, which is usually
triggered by invading microorganisms, destroys cells by building complexes
of proteins on cell membranes, causing the cells to burst.

Working on rabbit hearts, the Michigan team has shown that cocaine boosts
the production of complement proteins, causing the deadly complexes to form
on heart muscle cells and the endothelial cells that line the heart's blood
vessels.

The complement cascade is already known to damage heart tissue in some
circumstances (New Scientist, 25 April 1998, p 20). So, prompted by
Lucchesi's findings, doctors at the University of Michigan's hospitals are
now investigating whether drugs that block the cascade will help patients
suffering from cocaine overdoses.

Michael Davies of St George's Hospital in London, a cardiovascular
pathologist and assistant medical director of the British Heart Foundation,
says the Michigan team's research might explain why some young cocaine users
develop a form of heart failure in which the heart grows floppy and pumps
blood less efficiently. "This would fit quite well with the idea that
complement is damaging blood vessels or heart tissue," he says.

Larry Alexander of Baylor Medical Center in Dallas, a drug abuse spokesman
for the American College of Emergency Physicians, agrees: "The authorities
should be doing more to highlight the danger cocaine poses to people's
hearts."

Cocaine can also send coronary arteries into spasm. Alexander and other
specialists in emergency medicine believe this is the reason for a growing
number of young people turning up in hospital complaining of chest pain. The
vast majority are men, and they are usually discharged after doctors
establish that they are not suffering from a heart attack. Each case has to
be thoroughly investigated, however, which stretches hospitals' resources.

"At the weekend I saw three young males in their early twenties with chest
pains, and all three were positive for cocaine," says Alexander. "Normally
it just goes away. But occasionally it gets very serious and you'll see a
heart attack."

The link between chest pain and cocaine abuse isn't always clear, says
Alexander. And this could mean that statistics on the number of emergency
hospital visits caused by cocaine use (see below) are seriously
underestimated. Alexander also fears that people who repeatedly send their
cardiac arteries into spasm may suffer longterm heart damage.

John Henry, an expert on drug abuse at St Mary's Hospital in London, is
similarly concerned. He suspects that up to 10 per cent of people reporting
to hospital with chest pain owe their problems to cocaine abuse. Henry is
seeking ethical approval to carry out anonymous urine tests for cocaine on
everyone reporting to his hospital with chest pain.

Michael Day

Source: The Journal of Pharmacology and Experimental Therapeutics (vol 292,
p 201)