Disfigured blood cell enzymes may explain away the vampire myth and inspire revolutionary new treatments
by Originally posted 18 December 2006 Image: Paul Tanner
The night before Hallowe’en seems like the perfect time to talk vampires, blood, and burning flesh. But the discussion at the October 30th Royal Canadian Institute lecture was much less macabre than it was medical. David Dolphin, an organic chemist at the University of British Columbia in Vancouver, believes that a class of rare genetic diseases called porphyrias may explain the legends that inspired Dracula and his kin. What’s more, harnessing the power of these deadly diseases might be the key to immortality - or a cure for cancer.
Dolphin has spent years studying porphyrins, ring-shaped organic molecules that bind with metals. The most famous porphyrin rings are those found in the heme group - the red blood cell pigment responsible for catching and releasing oxygen. People with porphyria diseases have deformed hemes. There are seven main types of the disease, which range in rarity from one in 25,000 people to less than one in a million.
In sufferers, lone porphyrins build up in various tissues, especially the skin. They lie in wait like deadly little time-bombs that detonate when exposed to light by generating vicious free radicals which destroy the cells that house them. This violent reaction has led to porphryins’ nickname, “the pigments of death.” It might also explain vampires’ tendency to stray outdoors only at night, lest they burst into flames in the midday sun.
So were vampires really the blood-sucking undead of legend, or were they medically misunderstood in their time? Dr. Dolphin admits it’s only a theory but drinking blood would have allowed them to absorb more heme, which feeds back to ease up on excess porphyrin production. In fact, porphyria patients today get heme injections. Porphyrin build-up in teeth can make them appear reddish, possibly like bloody fangs. The disease is even associated with excess hair growth, especially on the forehead, possibly leading to the vampire’s trademark widow’s peak. The aversion to garlic may be explained by the fact that some chemicals in the plant, such as diallyl sulfone, increase the production of porphyrins in the body. Of course, he points out, that a wooden stake through the heart would kill anyone. As for the lack of a mirror image, Dolphin joked, “I’m a chemist, so I’ll leave that to the physicists.”
While the medical truth behind the vampire myth may always be a mystery, Dolphin is using the very earthly science of porphyrins and photodynamic therapy to help fight disease. As luck would have it porphryins like to accumulate in tumors. Like a nanoscopic Trojan Horse, Dolphin and his colleagues have experimented with injecting porphyrin-derived drugs into a patient with skin cancer. The drugs gather in the tumors and then Dolphin exposes the cancers to light. Judging by the photos in his presentation, the melanomas looked as if they had been burned right off on the very day of the treatment, much like the skin of a sunbathing vampire. And because of the drug’s preference for accumulating within fast-growing cancer cells, the healthy tissue around the tumors was unaffected. This drug is now being used to treat lung, bladder, cervical and esophageal cancers.
It’s kind of ironic that the disease thought to explain the mythology of vampires, themselves considered immortal, is helping people live longer today. I’m not sure those living in medieval times, however, would appreciate the scientific contribution to the future. “Can you imagine anything worse in the Middle Ages than having someone jump you at night and drink half your body’s blood?,” remarked Dolphin. But whether or not vampires really were porphyria sufferers, it does makes you wonder if the medical mysteries of today will inspire ghoulish myths centuries from now.