An external device that mimics the structure of a spleen can cleanse the blood of rats with acute sepsis, ridding the fluid of pathogens and toxins.
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, according to a paper published today (September 14) in Nature Medicine. 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” said lead study authorDonald Ingber, a professor at Harvard Medical School and founding director of the Wyss Institute in Boston.
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.
“It’s really an impressive demonstration of sophisticated bioengineering. The combination of the bio-artificial spleen and the engineered MBL protein is really elegant,” said Mitchell Fink, a surgeon and professor at the University of California, Los Angeles, who is working to develop new approaches to treat sepsis but was not involved in the present study.
The significance: Extracorporeal blood cleansing is not a novel concept for treating sepsis, said Fink. 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.