Monday, 16 February 2015

Poo transplant and weight gain: a case study

The case report detailed by Neha Alang and Colleen Kelly [1] (open-access) reporting on "new-onset obesity after receiving stool from a healthy but overweight donor" has already garnered some significant press attention (see the BBC entry for example). Reporting on that seemingly most undesirable but in some cases life-saving of measures - the fecal microbiota transplant (FMT) - whereby some of those trillions of wee beasties which inhabit our deepest, darkest recesses are transferred from one person to another, the authors add a cautionary caveat to our current fascination with such a technique.

The Alang/Kelly paper is open-access but a few pointers might be in order:
Interesting viewing @ Paul Whiteley

  • "A 32-year-old female with recurrent CDI [Clostridium difficile infection] underwent FMT". As per my previous mention of being a potentially 'life-saving' measure, FMT for CDI (recurrent CDI) is something which is now formally indicated, as per the directions from NICE here in Blighty. Such recommendations came on the back of quite a volume of science which suggested effectiveness particularly in hard to treat cases of CDI (see here).
  • For this patient, quite a few avenues of treatment had been previously tried but with little success. "After extensive discussion, the patient elected to undergo fecal transplant. As per the patient’s request, her 16-year-old daughter was chosen as the stool donor." Said donor was, we are told: "∼140 pounds (BMI of 26.4), but it increased later to 170 pounds." BMI by the way, stands for body mass index and 140 pounds is equivalent to about 63 kilograms rising to about 77 kilograms in new (weight) currency. 
  • Results: well, FMT worked in that the mother: "improved and did not suffer a further CDI recurrence after FMT". But... "The patient presented again 16 months after FMT, and reported an unintentional weight gain of 34 pounds. She weighed 170 pounds and had become obese (BMI of 33)." Diet and exercise seemingly did very little to aid in weight loss and also after 3 years post FMT she "developed constipation and unexplained dyspeptic symptoms."
  • The authors concluded that there was a link between her weight gain and FMT treatment and further instigated a policy: "to use nonobese donors for FMT."

Repeating the fact that this is a single case report and so cannot really inform about any generalisable relationship between a poo(p) transplant and weight gain/loss and that correlation does not necessarily imply causation, this is an interesting paper. The first thoughts running through my mind when reading this paper was a comment from Dr Emily Deans a few years back about poo transplants and ensuring: "if you ever have a fecal transplant, make sure it is from a slender, non-asthmatic, happy person!" Although said in jest, it appears that Dr Deans may have been on the money with at least part of her prediction.

Insofar as the possibility of a connection between the use of FMT and weight gain/loss, well, we have kinda seen evidence emerging that gut bacteria might be doing far more than just helping us digest our food or making the odd vitamin or two. I've covered something on the mouse - Akkermansia muciniphila weight study before on a sister blog (see here) and how in a mouse at least, certain types of bacteria might be implicated in energy homoeostasis. You could ask whether some profiling of the donor stool might be indicated in future attempts at FMT covering something like A. muciniphila and other potentially important species bearing in mind, the relationship is likely to be complex and not just limited to one type of gut bacteria being 'present or not'.

The other intriguing point that also arises from the Alang/Kelly paper is the idea that weight gain/loss might not solely be driven by the classical 'food in, energy out' relationship which many people cling to as an explanation of our current obesity statistics. Again, I've talked about this idea before on this blog (see here) and how factors such as sleep and gut bacteria might come into play in some cases, albeit with a lot more research required including some genetic input into proceedings. Probiotics (to 'alter' gut bacteria) for weight management is still a relatively new area of investigation despite some intriguing initial results [2].

More controlled studies are of course implied in this area. I might also advance the idea that a little more focus on other residents of the gastrointestinal (GI) tract might also be indicated in future work including the emerging idea of the gut virome and 'bacteriophages' (viruses attacking bacteria) as per what is being doing in other areas of interest to this blog [3]. That and further work on another of my preoccupations, gut barrier integrity bearing in mind things might not be entirely straight-forward [4].

Then to some music: Shame Shame Shame (shame on you).


[1] Alang N. & Kelly CR. Weight Gain After Fecal Microbiota Transplantation. Open Forum Infect Dis. 2015; 2: 1.

[2] Sanchez M. et al. Effect of Lactobacillus rhamnosus CGMCC1.3724 supplementation on weight loss and maintenance in obese men and women. Br J Nutr. 2014 Apr 28;111(8):1507-19.

[3] Yolken RH. et al. Metagenomic Sequencing Indicates That the Oropharyngeal Phageome of Individuals With Schizophrenia Differs From That of Controls. Schizophr Bull. 2015. Feb 9.

[4] Kless C. et al. Diet-induced obesity causes metabolic impairment independent of alterations in gut barrier integrity. Molecular Nutrition & Food Research. 2015. Feb 10.

---------- Alang, N., & Kelly, C. (2015). Weight Gain After Fecal Microbiota Transplantation Open Forum Infectious Diseases, 2 (1) DOI: 10.1093/ofid/ofv004