Characterizing Fecal Microbiota Treatment in Human Obesity

Severe overweight is also referred to as obesity. Obesity is a chronic disorder that can cause long-term health problems. Being overweight negatively affects quality of life and increases the risk of associated illnesses while overweight individuals are also often stigmatized by the society. Whilst weight loss strategies such as exercise, being on a diet, taking medication are only partly successful, surgical procedures (bariatric surgery) are more effective but also more invasive. Bariatric surgery involves removing part of the stomach just below the stomach entrance to reduce stomach size and rerouting the food passage through the small intestine so that food is digested more quickly. As a result, food intake is reduced and the body also absorbs less nutrients and calories from food. The microbiome describes all the bacteria that live in the human gut. The microbiome affects our metabolism, the way we eat, and how much we weigh. The type and number of the bacteria that live in the gut of slim and overweight individuals differ greatly. At present, scientists believe that an impaired gut microbiome causes obesity and reestablishing a healthy microbiome is necessary to lose weight and stay at healthy weight in the future. Clinical studies have shown that the bariatric surgery seems to reestablish the balance between the good and the bad gut bacteria which could also explain its long-term success in reducing and maintaining a reduced weight. However, since bariatric surgery is irreversible and poses a significant risk to the patient, it is considered the very last resort when treating obesity. This project explores an alternative, non-surgical treatment option for obesity which involves giving morbidly obese individuals a fecal transplant (also referred to as bacterial therapy). During fecal bacterial therapy bacteria from a filtered stool sample of a healthy donor is transplanted into the patients colon using colonoscopy. This procedure is used to reestablish the healthy gut flora because the vast number of bacteria that populate the gut cannot be grown in the lab. The project will also investigate how successful the transplant is depending on whether the patients receive a transplant from a donor with normal body weight or a donor who successfully underwent bariatric surgery. The transplant recipients metabolic reaction to the transplant and their body weight will be regularly monitored over a period of six months following the procedure.