A massive analysis of faecal transplant research has now driven these exceptional donors out of the cubicles and into the spotlight.
Trial after trial, researchers from the University of Auckland were able to pin the medal of remission on a single donor, whose stool was filled to the brim with all the best and most necessary bacteria.
“The pattern of success in these trials demonstrates the existence of ‘super-donors’, whose stool is particularly likely to influence the host gut and to lead to clinical improvement,” explains senior author Justin O’Sullivan, who studies how the microbiome can inform the treatment of complex disorders at the University of Auckland.
“We see transplants from super-donors achieve clinical remission rates of perhaps double the remaining average.”
The idea of super poopers has long been suspected, but this is one of the first overarching studies to substantiate their existence.
Past research has shown that passing poop from one individual to another is a reliable treatment for serious, recurrent infections of the gut (Clostridium difficile), no matter who the donor is.
Yet for some reason, when it comes to treating IBD and type 2 diabetes, faecal transplants appear to work less than a quarter of the time.
A number of studies suggest the different responses depend heavily on the stool donor and the quality of their donation. A paper from 2015, for instance, found that of all nine patients who entered remission after a poop transplant, seven of those patients received their stool from the exact same donor.
Unfortunately, when it comes to other chronic disorders, such as diabetes, research on the efficacy of faecal transplants is lacking and inferences are shaky, although there have been some hopeful findings.
For example, a short trial found that poop transplants for men with metabolic syndrome corresponded with a 75 percent increase in insulin sensitivity and a greater diversity of gut bacteria.
“It is well-known that responders typically exhibit a higher microbial diversity than non-responders,” O’Sullivan explains.
“In line with these observations, a larger number of species in the donor stool has been shown to be one of the most significant factors influencing faecal transplantation outcome.”
Each one of our guts is home to an abundant and diverse microbial community as unique as a fingerprint. And while there’s still a lot we don’t know about this complex entity, called the microbiome, it’s generally accepted that having a stable and diverse colony of gut bacteria is the healthiest.
Looking closer at the most successful stool samples, the researchers noticed these samples were, in fact, more diverse, with high levels of specific ‘keystone species’, which are often lacking in patients with IBD.
The findings suggest that if we can figure out a way to pick these super poopers out of a crowd, we might be able to improve the success rate of faecal transplants for IBD and other chronic conditions.
In all likelihood, however, the truth is probably more complicated. Just like many other medical donations, the success of faecal transplants is likely influenced by a host of factors, including genetic compatibility, immune reactions, and the presence of certain bacteria and viruses.
What’s more, these factors may vary depending on the type of disorder being treated. In other words, one stool does not fit all, no matter what super donor it may have come from.
“Our hope is that if we can discover how this happens, then we can improve the success of faecal transplantation and even trial it for new microbiome-associated conditions like Alzheimer’s, multiple sclerosis and asthma,” says O’Sullivan.
This study has been published in Frontiers in Cellular and Infection Microbiology.