Henning Gerke, MD, a University of Iowa specialist in gastroenterology and hepatology, offers his thoughts on this compelling topic.
While microorganisms are typically blamed for causing infectious diseases, it is becoming more and more evident that the microorganisms living in our large bowels play important roles in keeping us healthy.
These organisms—bacteria, fungi, protozoa—start colonizing the bowel in infancy. They appear to be important in training our immune systems and keeping pathogens (organisms that cause disease) in check.
Indeed, each of us has 10 times as many bacterial cells as human cells in our bodies.
These days, microorganisms in the human stool are no longer regarded as mere waste products. Rather—and this is the exciting part with lots of promise for the future—they are viewed more like organs in that they affect human immunity, digestion, and metabolism.
The idea that microorganisms are critically important for good health reflects a theory—the “hygiene hypothesis”—which supposes that a lack of early childhood exposure to environmental microorganisms and parasites can result in disease. We know, for instance, that certain autoimmune diseases are less common in countries with lower hygiene standards than those in the industrialized world. In this context, University of Iowa gastroenterologists David Elliott, MD, PhD; Robert Summers, MD; Joel Weinstock, MD, and others have conducted important pioneering research on treating inflammatory bowel disease with pig worms.
Stool transplantation (also called fecal microbiota transplantation or FMT) involves the transfer of stool from healthy donors to sick patients. Treatment is administered through a tube inserted into the patient’s stomach or small bowel or via stool enema or colonoscope. The goal is to re-establish a healthy diversity of microorganisms in the patient’s bowel.
So far, fecal transplantation is targeted primarily to patients with Clostridium difficile (C. diff) infection, which inflames the colon and causes diarrhea. Treating C. diff with antibiotics is challenging because infections tend to recur and antibiotic-resistant strains of bacteria are more common. Since the antibiotics might further disturb the diversity of gut microorganisms, it’s like fighting fire with fire.
Conversely, stool transplantation addresses the problem at its root. A healthy balance of microorganisms is re-established in the colon. It works surprisingly well, as documented by several clinical studies.
UI Hospitals and Clinics occasionally uses this method, having treated some 25 C. diff patients since March 2012.
At this point, no one knows if stool transplantation will prove valuable in treating other conditions associated with gut microbiota, such as inflammatory bowel disease, irritable bowel syndrome, obesity, and Type II diabetes. More research will become available in the next years to answer some of these questions.
Meanwhile, fecal transplantation remains a hot topic with the field of medical science.
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Stool transplantation is far from new and not limited to human conditions.
Fourth century Chinese medical literature mentions its use for treating food poisoning and severe diarrhea.
The influential 16th century Chinese physician, herbalist, and acupuncturist, Li Shizhen, used “yellow soup,” “golden syrup,” and other remedies containing fresh, dried, or fermented stool to treat abdominal diseases.
Today’s veterinarians practice “transfaunation,” a treatment for ruminating animals, known to the Italian anatomist, Fabricius Aquapendente (1533-1619). In transfaunation, stomach microorganisms are transferred from healthy donor animals to a sick animals, often leading to cures.
Advantages of Fecal Transplantation
Simple, effective (against C. diff infection), and cheap.
Inflammatory Bowel Disease
Stool transplantation for IBD (ulcerative colitis and Crohn’s disease)—where a direct impact of the gut microbiota on the disease process appears plausible—has sparked recent interest. Results of small, uncontrolled series are promising, but overall, the scientific evidence for IBD is very limited and study results are not uniform. Patients with IBD have an increased risk to contract C. diff infection, and a recent small study found improvement of symptoms related to the C. diff infection but no impact on the underlying IBD. Also, limited data suggest a benefit of stool transplantation with irritable bowel syndrome (IBS). Further research is needed.
Why Does it Work?
Human stool is the ultimate probiotic. Transplantation of stool helps re-establish a healthy balance and diversity of microorganisms in the colon. These organisms compete with C. diff and produce substances that inhibit its growth. C. diff does not thrive in such an environment.
Currently at University of Iowa Hospitals and Clinics, patients with recurrent C. diff infection (at least two relapses) despite adequate antibiotic treatment or those refractory to antibiotics are considered for stool transplantation. These are usually outpatients in fairly stable overall health. Stool transplantation can also be considered in hospitalized patient with severe disease and even in those who require treatment in the Intensive Care Unit. However, these patient need to be monitored closely and IV antibiotics and/or emergency surgery may be necessary, especially if massive colonic distension occurs (so-called toxic megacolon) or if there are signs to predict a complicated course with shock and multi-organ failure. Potential donors are screened for transmittable infectious diseases (including HIV, viral hepatitis and syphilis), and other conditions (including autoimmune diseases) that may be related to the gut microorganism.
What Has Research Told Us So Far?
There is a large body of evidence from published studies to suggest a very high efficacy of stool therapy for patients with C. diff infection who failed to be cured with conventional antibiotic treatment. While most of these studies were criticized for lacking a control group of patients who received conventional antibiotic treatment, a recent clinical trial directly compared patients who were randomly assigned to treatment with either antibiotics or stool transplantation. This trial demonstrated clear superiority of stool transplantation. However, methods of treatment with stool transplantation are not standardized. More work needs to be done to determine what constitutes the ideal stool donor, optimal method of stool preparation, and best route of administration. In the future, an industrial product might replace human stool. Work has already been done to put human stool in gel capsules and create synthetic stool from bacterial cultures that were derived from the stool of a single donor. Further research is also needed to determine if stool transplantation should be done as primary treatment for C. diff infection and not just in refractory or recurrent cases.
The “icky factor” is rarely a concern for patients receiving fecal therapy.