An “artificial spleen” that may help cure sepsis

One of the toughest parts of becoming older is that the immune system begins to work less well, leaving seniors vulnerable to more kinds of infections, which may also take longer to heal. At worst, these infections can lead to sepsis, which is “most common and most dangerous in older adults,” according to the Mayo Clinic. Some possible help may be on the horizon in several years in the form of an “artificial spleen.”

Created by researchers at Harvard’s Wyss Institute, the artificial spleen works in a way similar to dialysis: Infected blood is run through a machine, cleansed, and then re-circulated into a patient.

Bad stuff (in color). Good beads (in white), pulled into the “spleen.” Courtesy: Harvard's Wyss Institute

Bad stuff (in color). Good beads (in white), pulled into the “spleen.” Courtesy: Harvard’s Wyss Institute

While this may seem like technological overkill compared to simply swallowing an antibiotic, the challenge with sepsis is that it is extremely difficult to correctly diagnosis the underlying pathogens, which can all too quickly lead to fatal consequences.

“Studies have shown that every hour a patient receives the wrong antibiotic—even a strong broad-spectrum antibiotic—mortality increases by 5 to 9 percent,” according to Donald Ingber, the Wyss Institute’s Founding Director and leader of its Organs-on-Chips effort, as quoted in the MIT Technology Review.

The artificial spleen bypasses the need for a precise diagnosis and goes right to the cure: cleansing the blood of nearly all pathogens. The way it does this is an elegant combination of advanced nanotechnology and basic biochemistry. Patients are injected with magnetic nanobeads, which have been coated with a protein (mannose-binding lectin) that binds to sugar molecules on the surfaces of over 90 different bacteria, fungi, toxins and other nasty things.

Remember, the beads are magnetized, and the protein ensures that the nasties are sticking to them. The researchers send the bead/blood combo through the “spleen,” which contains a magnet that pulls away the beads. The cleansed blood can then be re-circulated in the patient.

Optimistically, clinical trials could begin in a few years. Because the artificial spleen is external and likely to be classified as a medical device, FDA approval would likely come in three to five years after the completion of the trials, providing they are successful. However, because the protocol involves injecting the patient’s blood with nanobeads, it could fall under the longer approval process required for medications. One advantage that could hasten its approval: among the device’s funders is the Defense Advanced Research Projects Agency, which hopes to use it for soldiers suffering from wound-related infections.