His victims include actor Christopher Reeve, Pope John Paul II, and the British poet Rupert Brooke, who died after a mosquito bite on her lip became infected. Sepsis remains one of the leading causes of death in the United States and worldwide. Now, researchers describe a new way to treat the deadly disease by filtering germs blood of patients.
Sepsis is over-the-top of the reaction of the organism to infection. Even with modern medical care, it can lead to organ failure and death within hours. Measures such as early treatment with antibiotics-which broad-spectrum kill many types of bacteria reduces mortality in recent years, but no drugs specifically target sepsis. Cell biologist and bioengineer Donald Ingber of Harvard University and his colleagues wanted to test a therapy a different technique to shoot the microbes and toxins they release into the blood. As the design guide, the researchers studied the spleen; the organ filter pathogens and poisons the blood wends through its narrow passages.
The first team needed a way to capture nasties. They have magnetic beads coated with tiny fragments of the lectin known as mannose-binding protein (MBL). In our body, MBL helps fight against the pathogens snap on them. Ingber and colleagues have shown that the sticky beads can enter a variety of microbes in the test tube.
With this key challenge of the road, researchers were ready to design the rest of the system. They designed a microchiplike device slightly larger than a deck package that works much like a dialysis machine. As blood enters the device, it receives a dose of magnetic beads, which snapped bacteria and fans in 16 channels. As blood flows through the device, a magnet pulls the beads-and all microbes or toxins stuck to them, the blood drop in neighboring channels containing saline.
The researchers first tested their device with donated human blood contaminated with bacteria. They found that the filtering of the blood through the device five times could remove 0% of the microbes.
Next, Ingber and his team hung anesthetized rats to a pump that circulates blood through the device, and then returned to their bodies. After dosing rats with bacteria, the researchers measured the effectiveness of their system. 1 hour, the device removed 0% of the microbes in the blood of rats, the team reports online today in Nature Medicine .
In determining whether filtering improved blood survival, the researchers injected a lethal bacterial toxin in anesthetized rats and then used the device to filter poison the blood of certain animals. Eighty-six percent of the control rats died during the experiment 5 hours. If their blood has been cleaned, however, only 11% of the animals perished. Although the pearls do not bind to all kinds of infectious microbes, "we get most of the bugs that are the most frequent causes of sepsis," says Ingber. In addition, because MBL focuses on an assortment of invaders, including viruses, the device could potentially eliminate pathogens that cause other blood diseases, including HIV and perhaps Ebola, he said. it may also help treat diseases caused by abnormal blood proteins, such as autoimmune diseases.
"This is a very promising study using a very creative system," says Richard Wenzel, an infectious disease specialist at Virginia Commonwealth University in Richmond.
But skeptics say it is unclear whether the technique can be used for the intended purposes, the treatment of sepsis. "What they have done is to invent an artificial spleen," says Clifford Deutschman, medical care and sepsis critical researcher in Jewish Hofstra North Shore-Long Island School of Medicine in New Hyde Park, New York. It think the device might help many types of patients, including those with injuries of the spleen. But people with sepsis usually are not microbes or toxins in the blood, he said, so there may be nothing to remove.
Ingber not agree. He notes that antibiotics often benefit sepsis patients, reducing the number of microorganisms should be beneficial. "that should help out the bugs," dit- he. He and his colleagues plan to test the device in pigs, which more closely mimic human sepsis.
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