What Can FMT Tell Us About Other Diseases?

Netherland researchers tracked instances of the C. difficile therapy to as far back as 300 AD, in China.

Studying fecal microbiota transplantation (FMT) can allow researchers to identify novel therapeutic targets for metabolic syndromes, according to a new literature review.

Researchers from the Netherlands reviewed the history of FMT, the present evidence on its role in the pathophysiology of metabolic syndrome and its efficacy, limitations and future prospects. The study authors found that in China, as early as 300 AD, “yellow soup” or “golden syrup” was applied in cases of food poisoning and diarrhea.

Later on, by the 16th century, China developed feces-derived products as a cure for gastrointestinal ailments, fever, and pain. The investigators also wrote about the modern era, discovering that the earliest record of an FMT for a non-infectious disease took place in a 45-year-old male with refractory ulcerative colitis — he achieved a clinical recovery.

FMT is sometimes used to treat Clostridium difficile (C. difficile) infection; 3 randomized controlled studies have shown cure rates of 90% or higher with this treatment method. Other reports have detailed alleviated symptoms after FMTs for patients with multiple sclerosis, Parkinson’s disease, and chronic fatigue. And in one other study involving mice, FMT was theorized to possibly help children with severe malnutrition.

The researchers also detailed the rise of “new onset obesity” among FMT patients, and discussed the trend in studies that suggest a causal relation between the gut microbiota and the metabolic syndrome. However, they wrote, the pathophysiologic pathways have still not been explained.

“There is a firm base of evidence linking the spectrum of metabolic dysfunction seen in metabolic syndrome to inflammation,” the researchers wrote.

Additionally, the “leaky gut” was also attributed to a decline in metabolic function. This theory involves an impaired gut barrier functionality and leakage of gut microbiota and/or bacterial components into the system, resulting in a variety of negative effects. One way researchers suggested to test for a leaky gut was to look for bacterial signatures in the circulation.

Some of the ways that the gut microbiota can contribute to the metabolic system include the production of signaling molecules from the gut microbes affecting gut integrity, poor mediation of bile acids, and malevolent microbes that contribute to insulin resistance — namely, Prevotella copri and Bacteroides vulgates.

The researchers noted gut microbes are involved in many aspects of the metabolic syndrome and can contribute to atherosclerosis, hepatic steatosis, elevated blood pressure, and dyslipidemia.

Upon examining this evidence, the researchers wrote that now is "the time to further investigate these claims using well-designed randomized placebo-controlled studies featuring FMT that focus on unraveling the mechanisms through which gut bacteria interact with host metabolism."

They suggest doing this through the monitoring of microbiotal changes, genetic and epigenic effects, and exploring dietary habits. Doing this can pave the way for more personalized strategies for manipulating the microbiota, they wrote.

While FMT still has some obstacles to overcome — such as risk infection, or microbiota associated disease, or the “yuck factor” – the US Food and Drug Administration (FDA) has determined that FMT is classified as a biologic product, thus the process remains under FDA jurisdiction. In Europe, that is not the case, leaving the burden of additional research on investigators in that part of the world.

The report, titled “Fecal microbiota transplantation in metabolic syndrome: History, present and future,” was published in the journal Gut Microbes.

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