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. 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.
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. Normally it just goes away. But occasionally it gets very serious and you'll see a heart attack.