Can you “bank” your microbiome?
Imagine what it would be like to have your gut bacteria stored away
somewhere, then fed back into you one day.
Disease and serious illness are a sad part of life, affecting the healthiest
of us, often out of the blue.
Of course the human body has evolved a sophisticated immune system
which usually does an amazing job of battling pathogens.
The fact that it’s called a “system” should serve as a reminder that it’s not a
single entity, but a complex network of organs, tissues, and cells working
together to protect the body, and included in this setup is the microbiome, the
rich diversity of bacterial life that lives in and on the human body.
But sometimes even the most robust immune system may not be up to the job
of providing protection, and even supposedly helpful treatments can
themselves have unwanted side effects that a compromised immune
system can do little to battle.
Doctors are recognizing this and learning that patients’ recoveries can be
sped up if their microbiomes are somehow protected.
But how do you do this when an invasive treatment such as chemotherapy or
radiation tends to kill a patient’s healthy cells alongside their cancer cells?
Italian researchers, for example, found that children receiving treatment for
bone marrow or blood cancers such as multiple myeloma or leukemia
experienced an enormous influx of new bacterial species post–treatment, but
saw less than 10% of their original microbiota remain.
One way to protect the microbiome is both simple and effective, but sounds
Just like “banking” a patient’s own blood before an operation, a patient’s gut
microbiome can be stored, then returned after treatment.
And it’s done via what might best be termed a “stool deposit”.
Basically a patient’s feces are mixed with saline solution in a special lab
blender called a “Stomacher”, then stored in a freezer at -70°C.
When it’s time to re-inoculate the patient, it can go back in either via a tube
down the nose, or up the other end during a colonoscopy or even as an
enema. Not exactly a pleasant thought, I know, but actually these procedures
are also used in fecal microbial transplants (FMT) which we’ll talk about in a
future Monday email.
Yup, you’ve got that one to look forward to.
Doctors at the world’s largest private cancer center, the Memorial Sloan
Kettering in Manhattan, use the procedure as part of bone marrow treatments,
calling it “autologous restoration of gastrointestinal flora” which while sounding
rather complex and clinical is maybe more patient-friendly than labelling it a
poop transplant. (“Autologous”, by the way, means cells or tissue obtained
from the same individual.)
Similarly, clinicians at North York General Hospital in Toronto bank patients’
stools in case they experience a hospital acquired infection such as C. diff.
Although fecal transplants can also be used effectively in this situation,
using a patient’s own poop spares them from exposure to bacterial species
that may be harmful. It also avoids the need for the time-consuming and expensive
testing necessary when fecal matter is transplanted from one person to another.
You see, hospital acquired infections are a giant problem.
At any given time in the USA, around one in 25 inpatients has an infection
related to hospital care, leading to the loss of tens of thousands of lives every
Reacquiring your own stool admittedly sounds like a pretty rough procedure.
Not so nasty if it ends up saving your life, though.