Sepsis is a serious threat to the old, but researchers are developing new forms of blood cleansing devices that more effectively target the causes of this condition by removing pathogens from the blood. Looking ahead, one can imagine an evolution of this technology into long-term implants that could augment immune system function for everyone, providing far greater resistance to many threats to health:
A microfluidic device filled with magnetic nanometer-sized beads that bind a plethora of pathogens and toxins was able to clear these invaders from the blood of rats with sepsis, improving their outcomes. The design of the extracorporeal device was inspired by the small vessels and sinusoids within the spleen, through which blood "trickles slowly, almost like in a wetlands, efficiently capturing pathogens".
The device has two interconnected channels, one for the flowing blood and another containing a saline solution that traps and removes the pathogens. Magnetic nanobeads coated with a genetically engineered version of the mannose binding lectin (MBL) protein - which has a natural proclivity for foreign toxins and bugs, and normally functions as part of the mammalian innate immune system - are injected into the flowing blood before it enters the device.
Extracorporeal blood cleansing is not a novel concept for treating sepsis. An antibiotic-coated column called Toraymyxin that is approved in Japan and Europe - currently in a Phase 3 clinical trial in the U.S. - can remove endotoxins from the blood and has been shown to improve outcomes for sepsis patients. Other dialysis-like devices have been developed to mitigate the symptoms of sepsis, and these have included hemofiltration of the inflammatory molecules that are the root of the so-called cytokine storm that spurs organ damage in sepsis patients. But previous approaches did not target the cause of the storm - pathogens.
"Some already available blood-cleansing technologies have negative side effects like depletion of platelets, white blood cells, or other proteins along with the deleterious elements. What I like a lot about this approach is that it appears safe and there is no blood coagulation or altering of the blood composition - that is really important."