by FIONA MACDONALD / (15 September 2014)
“Researchers have developed an artificial spleen that cleans up blood infections.
Scientists from the US have developed a new, high-tech device that can clear infections from blood – even those caused by unknown pathogens.
The technology was inspired by our own spleen, and, as Sara Reardon reports for Nature News, it can rid the blood of “everything from Escherichia coli to Ebola”.
Blood infections are extremely difficult to treat and can lead to sepsis – an extreme immune response that can be fatal. More than half of the time, doctors don’t know what causes these blood infections, and they have to rely on broad-scale antibiotics in an attempt to treat the original infection, Reardon explains. This isn’t always effective, and can lead to antibiotic resistance.
But this new artificial “biospleen”, developed by a team of researchers led by Donald Ingber from Harvard University’s Wyss Institute for Biologically Inspired Engineering in Boston, promises to filter the blood and get rid of these infections more effectively.
The device’s power lies in a special, magnetic-nanobead filter. To create the filter, the scientists took magnetic nanobeads and coated them with a modified version of a protein called mannose-binding lectin (MBL). This protein is found in humans and it binds to sugar molecules on the surface of more than 90 different bacteria, viruses and fungi – including the toxins that dead bacteria release, which can trigger sepsis.
As a patient’s blood passes through the biospleen, these MBL-coated magnetic nanobeads bind to the majority of pathogens. A magnet in the artificial spleen then pulls the beads and the bacteria and viruses they’re attached to out of the blood, leaving the blood purified and ready to be pumped back into the patient.
The device has now been tested on rats infected with either E. coli or Staphylococcus aureus. Five hours after infection, 89% of the rats whose blood had been filtered through the biospleen were still alive, compared to only 14% of those who were not treated. Impressively, the scientists found that the device had removed more than 90% of the bacteria from the rats’ blood. The results are published in Nature Medicine.
“The rats whose blood had been filtered also had less inflammation in their lungs and other organs, suggesting they would be less prone to sepsis,” writes Reardon.
The team then tested the biospleen on five litres of blood, which is the volume in the average human, and found that within five hours, the device could remove most pathogens.
Reardon explains at Nature News: “That degree of efficacy is probably enough to control an infection, Ingber says. Once the biospleen has removed most pathogens from the blood, antibiotics and the immune system can fight off remaining traces of infection — such as pathogens lodged in the organs, he says.”
The biospleen could also be used to treat viral infections such as HIV and Ebola, according to Ingber, and testing as now begun in pigs.
Nigel Klein, an infection and immunity expert at University College London in the UK, told Reardon that he expects the biospleen could be trialled in humans within a couple of years.”