Fecal microbiota transplantation (FMT) did not result in additional weight loss for patients with obesity following bariatric surgery.

A team, led by Perttu Lahtinen, MD, Department of Gastroenterology, Päijät-Häme Central Hospital, tested FMT from lean donors as a body weight reduction measure and identified whether the treatment further improves the results of bariatric surgery in patients with obesity.

Obesity and FMT

While obesity has become a major public health crisis in recent decades, a small percentage of patients are resistant to treatment options, such as bariatric surgery.

The intestinal microbiota has emerged in recent years as a potential target to treat obesity.

Fecal microbiota transplantation is a relatively new treatment that involves taking feces from healthy donors to rebuild the gut microbiota of a diseased individual. FMT is delivered through upper or lower endoscopy via enemas or capsules.

In recent years, FMT has emerged as an effective treatment for recurrent C difficile infections, with cure rates of 82-88%. In fact, FMT has shown more efficacy than the antibiotics commonly used to treat the infections.

Some animal studies have shown FMT could be an effective avenue, if it is from a lean donor.

“The differences in the intestinal microbiota of lean and obese individuals and established causality between the intestinal microbiota and body weight in animal models have fostered research on FMT for obesity and compromised metabolism and have resulted in slight improvements in insulin sensitivity, abdominal adiposity, and lipid metabolism but have had less effect on body weight to date,” the authors wrote.

The Study

In the double-blinded, placebo-controlled, multicenter, randomized clinical trial, the investigators examined 41 adult patients with severe obesity between 2018-2021 at 2 bariatric surgery centers in Finland. The analysis included 18 months of follow-up. The mean age of the patient population was 48.7 years and 71.1% (n = 29) of the patient population was women. The mean body mass index (BMI) was 42.5.

FMT from a lean donor (n = 21) or from the patient (n = 20) was administered by gastroscopy into the duodenum. The participants with FMT from themselves was considered the autologous placebo group.

The investigators sought main outcomes of weight reduction, measured as the percentage of total weight loss.

No Differences Found

In the 6 months following FMT, 34 participants underwent LRYGB and 4 individuals underwent LSG. In addition, 82.9% (n = 34) of participants attended the last visit 18 months following the baseline visit ad the percentage of total weight loss at 6 months was 4.8% (95% CI, 2.7-7.0%; P <.001) in patients treated with FMT, compared to 4.6% (95% CI, 1.5-7.6%; P = .006) in the placebo group.

Overall, there was no difference observed between the 2 groups.

A similar trend was found at 18 months. Here, the investigators found the percentage of total weight loss was 25.3% (95% CI, 19.5-31.1; P <.001) in patients treated with FMT, compared to 25.2% (95% CI, 20.2-30.3; P <.001) in the autologous placebo group.

Once again, no different was found between the 2 groups.

“FMT did not affect presurgical and postsurgical weight loss,” the authors wrote. “Further studies are needed to elucidate the possible role of FMT in obesity.”

The study, “Effectiveness of Fecal Microbiota Transplantation for Weight Loss in Patients With Obesity Undergoing Bariatric Surgery,” was published online in JAMA Network Open.