Harvard scientists propose widespread banking of stool samples for fecal transplants later in life

Concept would allow individuals to ‘rewind’ and ‘rejuvenate’ their microbiome, ensuring a strong gut in old age

A potentially groundbreaking concept may ensure a healthy gut microbiome as people get older, allowing them to avoid disease. Researchers from the Harvard Medical School and Brigham and Women’s Hospital are proposing the widespread banking of stool samples for fecal transplants later in life.

Gut microbiome has changed dramatically over the past few decades with the way humans live and eat. These changes have been linked to increased rates of conditions such as asthma, allergies, digestive system diseases and Type 2 diabetes. Researchers believe we can battle these trends that are ticking upwards by having individuals bank samples of their own gut microbiota when they are young and healthy for use later in life in an autologous fecal microbiota transplant (FMT).

“The idea of ‘rewinding’ the human microbiome has taken off in recent years and has been hotly debated from medical, ethical, and evolutionary perspectives,” says corresponding study author Yang-Yu Liu, associate professor of medicine at Harvard and and associate scientists in the Channing Division of Network Medicine at Brigham and Women’s Hospital, in a statement. “It is still unknown if people in industrialized societies can gain some health benefit by restoring their microbiome to an ancestral state. In this paper, we proposed a way to rejuvenate the human gut microbiome.”

Donor stool has been used in FMTs to treat infections like Clostridioides difficile, which affect about 500,000 people and kill 29,000 annually in the United States. The one issue using donor stool, though, is there is variability in the host’s response, which is likely due to genetic and environmental differences between the donor and host.

Fecal transplants
Hypothetic workflow of rejuvenating the human gut microbiome by stool banking and autologous fecal microbiota transplantation (FMT). (Credit: Trends in Molecular Medicine)

A nonprofit based in Somerville, Massachusetts, is allowing individuals to bank their own stool. OpenBiome is the first stool bank to offer an option for people to bank their own stool for future treatment of C. diff infection. Researchers analyzed whether this might be feasible on a large scale for other diseases.

“Conceptually, the idea of stool banking for autologous FMT is similar to when parents bank their baby’s cord blood for possible future use,” explains Yang. “However there is greater potential for stool banking, and we anticipate that the chance of using stool samples is much higher than for cord blood.”

Yang added there are “many practical issues to implementing this idea,” like optimal storage methods, how much stool should eventually be banked, and how much it would cost.

Study co-author Shanlin Ke, a postdoctoral research fellow in Yang’s lab, says more research is needed to test longer storage times for stool banks.

“Autologous transplants would naturally avoid or at least mitigate donor-recipient compatibility issues, but a major disadvantage of autologous transplants is the need for long-term cryopreservation of stool samples, typically requiring liquid nitrogen storage,” says Ke. “The long-term safe storage and subsequent resuscitation and cultivation of stool samples is a fundamental research question by itself. To inform practical guidelines for stool banking, further research is needed to systematically test longer storage times and preservation, resuscitation, and cultivation procedures.”

Researchers acknowledged lower income people might be left out due to cost, while higher income individuals would be able to take advantage.

“We do not anticipate that all individuals in our society are willing or able to pay the cost associated with the service of ‘rejuvenating’ their gut microbiome, in the same way that not all parents pay the cost of cord blood banking for their newborns,” says Yang. “But as scientists our job is to provide a scientific solution that may eventually benefit human well-being. Developing a reasonable business model and pricing strategy so that the solution is affordable to everyone would require the joint force of entrepreneurs, scientists and perhaps governments.”

The study is published in the journal Trends in Molecular Medicine.

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