Fecal microbiota transplantation in adolescents with obesity induces limited and donor-dependent remodeling of the gut microbiome (Sep 2026, n=87) FMT
- Thread starter Michael Harrop
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Fecal Microbiota Transplants
IsthmusSIBO
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Well, at least it’s one more to the list giving attention to the need of finding a super-donor.
Doesn’t translate into action though.
Doesn’t translate into action though.
The two most worth commenting-on aspects of this work are (IMO):
A) They did not measure ANY markers of host metabolism or function at all. Not weight gain or loss, blood lipid levels, nothing. So when they speak of "response", they are SOLELY referring to how close the post-FMT samples of the recipients were to the donors. There is no reason to assume that higher similarity to the donor necessarily means that the FMT was more effective. It could potentially even be that the donors whose recipients ended up closest to them had many aggressive, opportunistic pathogens that the recipients would have been better off not getting much of. In any case, the optimal similarity for recipient health could be somewhere in the middle, having enough recipient-specific strains to perform host-specific functions or avoid immune triggering while having enough donor strains to fill the "holes".
B) They sex-matched donors to recipients, so they must have had a theory a priori that this could be helpful. This is the first research study that I have seen that did this, and in fact for many of the other studies that used just one or maybe two donors it wouldn't have even been possible to do this. They were in a sense lucky to have access to four female and five male donors, so they could sex-match and still be able to compare different donors while controlling for recipient sex.
They state in the results that donor identity seems to be more important than recipient sex, however they actually can't answer whether recipient sex has an effect since male and female recipients by design got different donors. All they can say is that it's possible to find donors for both male and female recipients who transmit a similar amount of microbes to each, but not whether these are the same donors.
Aside from the above two issues, which are needed to put the findings into perspective, they noticed some things about donor microbiomes in and of themselves. In particular, it was interesting that fungal diversity varied inversely with bacterial and viral diversity, and the "best" donors (with the above caveat) had high bacterial and viral diversity but low fungal diversity.
A) They did not measure ANY markers of host metabolism or function at all. Not weight gain or loss, blood lipid levels, nothing. So when they speak of "response", they are SOLELY referring to how close the post-FMT samples of the recipients were to the donors. There is no reason to assume that higher similarity to the donor necessarily means that the FMT was more effective. It could potentially even be that the donors whose recipients ended up closest to them had many aggressive, opportunistic pathogens that the recipients would have been better off not getting much of. In any case, the optimal similarity for recipient health could be somewhere in the middle, having enough recipient-specific strains to perform host-specific functions or avoid immune triggering while having enough donor strains to fill the "holes".
B) They sex-matched donors to recipients, so they must have had a theory a priori that this could be helpful. This is the first research study that I have seen that did this, and in fact for many of the other studies that used just one or maybe two donors it wouldn't have even been possible to do this. They were in a sense lucky to have access to four female and five male donors, so they could sex-match and still be able to compare different donors while controlling for recipient sex.
They state in the results that donor identity seems to be more important than recipient sex, however they actually can't answer whether recipient sex has an effect since male and female recipients by design got different donors. All they can say is that it's possible to find donors for both male and female recipients who transmit a similar amount of microbes to each, but not whether these are the same donors.
Aside from the above two issues, which are needed to put the findings into perspective, they noticed some things about donor microbiomes in and of themselves. In particular, it was interesting that fungal diversity varied inversely with bacterial and viral diversity, and the "best" donors (with the above caveat) had high bacterial and viral diversity but low fungal diversity.