Proper gut microbiota establishment begins in the moment we are born and is shaped by lifestyle and environmental factors in subsequent years. In some cases, the degree of dysbiosis is so severe that there is not turning back and practical dietary/lifestyle recommendations are useless.
The logic behind this intervention is simple: it tries to "reset" the gut microbiota. It has shown promising results in intestinal bowel disease (IBD) and resistant Clostridium difficile infections. The following protocol is taken from Silverman et al (1). My intent is to facilitate information, not to encourage the realization of this protocol without medical supervision. Interested persons should consult with their doctors before doing any procedure of this nature. Donors and recipients should be examined carefully before the intervention. The complete set of tests can be consulted in the mentioned study.
Recipients are initiated on maintenance therapy with oral Saccharomyces boulardii (probiotic), 500mg orally, twice per day. Metronidazole (500mg/3 times per day, PO) or vancomycin (125mg/4 times per day, PO) are also used. Both are antibiotics normally used against C.difficile infections.
- 1 bottle of normal saline (200mL)
- 2 standard 2 quart enema bag kits (available at drug stores)
- 3 standard kitchend blenders (1L capacity) with markings for volume
- Vancomycin/metronidazole should be stopped 24-48 hours before procedure.
- S.boulardii should be continued during the transplant and 60 days afterwards.
1. Add 50mL of stool (volume occupied by solid stool) from the healthy donor immediately prior to administration (< 30 minutes) to 200mL of normal saline in the blender.
2. Mix until getting a "milkshake" consistency.
3. Pour mixture (approximately 250mL) into the enema bag.
4. Administer enema to the recipient following the kit instructions. The patient should hold the infusate as long as possible and lie still as long as possible on his/her left side to prevent the urge of defecation. The procedure should be ideally performed after the first bowel movement.
5. If diarrhea recurrs within 1 hour, the procedure may be immediately repeated.
Modifications and perspectives
This procedure was made to treat C.difficile infections. Accordingly, the antibiotics and the probiotic used aimed to eliminate C.difficile from the gut. However, there are certain modifications which can be useful for treating severe dysbiosis. First, broad-spectrum antibiotics can be used to wash out most bacterial species and reduce colonization resistance. In addition, utilization of probiotics such as Bifidobacteria or Lactobacilli during and after the treatment should help preventing colonization by enteropathogenic species. Why Bifidobacteria? The use of broad-spectrum antibiotics increases the risk for colonization of enteropathogens. Bifidobacteria competes and prevents colonization by these pathogens directly and indirectly, via production of antibacterial molecules (2). In addition, dysbiosis is characterized by low levels and expression of Foxp3+ Tregs, which compromises immune tolerance and promotes inflammation. Oral administration of B.infantis has been shown to increase expression of Foxp3+ and IL-10 in peripheral blood and to drive maturation of dendritic cells towards a regulatory phenotype (3), and certain strains of Bifidobacteria are capable of modulating the plasticity of Th17/Treg populations in human PBMCs (4). On the other hand, Lactobacilli has also shown protective properties (specially against vaginal infections) (5) and competes with enteropathogens for adhesion on intestinal epithelial cells (6). Importantly, the effects over Treg induction and T cell differentiation differ between strains from the same species. I should address this issue in future posts. One thing that is not emphasized in the above protocol is the importance of diet for maintaining a correct microbiota. This, in my opinion, is key to success.
It is worth noting that because of the nature of the procedure, the microbiota of recipient subjects is altered and reduced, but not completely eliminated such as seen with studies in fecal transplantation. The utilization of fecal transplantation in humans is promising and should result in better outcomes. Indeed, positive preliminary results from the FATLOSE trial (7, 8) have been recently published in which patients with metabolic syndrome improved insulin resistance and lipid profiles after feces infusion from healthy donors. The positive results seem to be correlated with increases in colonic butyrate concentrations. These results fit nicely with the ones found previously with fecal transplantation in obese mice.
Turnbaugh et al (9) found astonishing differences in the microbiome of obese mice, compared to lean mice (greater abundance of Firmicutes). Metagenomic analysis revealed that the obese microbiome is enriched for EGT (environmental gene tags) encoding many enzymes invoved in the break down of otherwise indigestable dietary polysaccharides. These included KEGG pathways for starch/sucrose metabolism, galactose metabolism and butanoate metabolism. Increased concentrations of butyrate and acetate were also observed, as the fact that obese mice were able to harvest more energy compared to lean mice (assessed by less energy remaining in feces by bomb calorimetry,). Despite equal amount of food consumed in both groups, colonization of lean mice with obese microbiota led to an increase in bodyfat percentage of approximately 47% after two weeks. The potential for fecal bacteriotherapy in the treatment of several diseases has been observed in different animal models of inflammatory and autoimmune diseases.
Thus, it seems possible that future therapies for obesity, metabolic syndrome and other inflammatory/autoimmune conditions will aim to modulation of the gut microbiota.