Faecal transplants have been found to treat diabetes-related nerve pain, a complication affecting more than half of people with diabetes that causes tingling, numbness and stinging.
Liping Zhao at Rutgers University in New Jersey and his colleagues analysed faecal samples from 86 people, 27 of whom had diabetes-related nerve pain and 30 of whom had diabetes without nerve pain. The rest did not have diabetes.
Genetic sequencing revealed a greater abundance of 13 bacteria in people with diabetes-related nerve pain than in those without it. On average, these species constituted almost 12 per cent of the gut microbiome in people with this neuropathy and less than 2 per cent in people without it, indicating that an altered gut microbiome may underlie nerve pain in people with diabetes.
So, the team transplanted faecal samples from people without diabetes into a separate group of 22 participants with diabetic nerve pain. An additional 10 people with the condition received a placebo of pumpkin and potato powder.
The researchers assessed participants before treatment and 84 days afterwards. On average, nerve pain decreased by about 35 per cent in those who received the transplant and about 5 per cent in those who didn’t. Additional genetic analysis found that improvements were associated with a distinct cluster of gut bacteria that reduces inflammation, which is known to underlie chronic pain. One of these is Faecalibacterium prausnitzii, which has previously been found to be lacking in people with chronic fatigue syndrome.
Currently, there are no treatments approved specifically for diabetic neuropathy, but these findings suggest faecal transplants are a viable option. The procedure may alleviate nerve pain in other conditions as well, says Zhao. However, after three months, the effects began to fade.
Even so, these findings could lead to other ways of alleviating diabetes-related nerve pain, such as nutritional interventions that foster beneficial gut bacteria, says Mindy Patterson at Texas Woman’s University. “Diet is the number one influence on [the] gut microbiome,” she says.
She adds that future research should account for diet and other lifestyle factors, such as physical activity, that are known to influence gut bacteria – something this study did not do.