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Monday, August 22, 2011

A Malaria Treatment So Wacky It Just Might Work--Someday

The New York Times has a very interesting story today about a project that is being funded by the Gates Foundation to try to bring malaria under control. The idea is to treat patients (mice, to begin with) by placing them (or parts of them) in a very low wattage microwave. It will be some time before we know if this treatment will work to rid a body of malaria, but the article's main value is that in interviewing one of the method's co-inventors, Dr. Jose Stoute at Penn State, it provides a very nice summary of the complex biology of the malaria parasite, which helps us understand why this parasite has been a nemesis for thousands of years.
The idea, he said, is based on the fact that malaria parasites invade red blood cells and eat the hemoglobin inside them. Hemoglobin contains iron — and, as any bozo who’s ever tried to heat up a sandwich wrapped in tinfoil knows, it’s a bad idea to microwave metal.
Of course, the red cells containing parasites are floating along in arteries right next to healthy red cells, so whatever damage the microwave does to the parasites cannot be visited on the healthy cells, too.
And that, Dr. Stoute said, is where a crucial difference comes in: When a malaria parasite digests hemoglobin, it converts the iron into an inert crystalline pigment called hemozoin. The parasite must do that because free iron will tear oxygen atoms off things the parasite wants intact, like its cell membrane. The hemozoin crystals, packed with concentrated iron, are pushed into the parasite’s food vacuole — the empty space where a rudimentary creature that does not have a gut dumps its waste products. Drifting into an electromagnetic field with a vacuole full of hemozoin is about as brainy as stepping into a microwave with a stomach full of nails. But parasites don’t have brains, either.
Dr. Stoute and Dr. Spadafora [his co-inventor] have shown that they can fine-tune a custom-built microwave so that only the parasites are damaged. Their theory is that the heated-up hemozoin swells the vacuoles till they pop, unleashing an acid bath on the parasite’s innards. 
Even if the approach works in mice, all sorts of problems will have to be worked out before it is tested on humans, Dr. Stoute said. Hot spots like those that a microwave creates in liquids must be avoided. And any patient will undoubtedly need treatments for several days in a row, because the parasites hide in the brain, liver and spleen — and microwaving the head or abdomen is probably a bad idea.
“But eventually they have to come back out into the blood,” he said, “and that’s when we’ll get them.”
Since malaria parasites have shown an ability to develop resistance to all know drug therapies, we need to keep our fingers crossed for this idea, no matter how crazy it seems at first glance.

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