Relation between gut microbiota COmposition of smaLL intestine and faECes in healThy subjects

Worldwide the prevalence of obesity and type 2 diabetes (T2DM) continues to
rise at an alarming pace. Due to the development of new analytical methods the
importance of the intestinal microbiome in the pathophysiology of these
metabolic disorders has become clear. A disturbance in the gut microbiota
composition can disturb the body*s metabolic functions. Obesity has been
associated with changes in the composition of the gut microbiota and the obese
microbiome seems to be more efficient in harvesting energy from the diet. Lean
male donor faecal transplantation in males with metabolic syndrome resulted in
a significant improvement in insulin sensitivity in conjunction with increased
intestinal microbial diversity. Such differences in gut microbiota composition
might function as early diagnostic markers for the development of T2DM in high
risk patients. However, in order to strengthen the predictive potential of the
microbiota composition, more scientific data needs to be gathered. Gut
microbiota composition is thought to differ across different parts of the GI
tract and significant differences have been found between colonic biopsies and
faeces samples, while other findings contradict this. These conflicting data
call for further research to elucidate the relationship between the composition
of small (duodenal) and large (faecal) microbiota composition. Therefore we aim
to investigate the relation between gut microbiota composition of the small
intestine and faeces by collecting and analysing stool samples and small
intestinal biopsies of 70 healthy subjects who are planned for a routine
gastroscopy and compare these data with our already determined gut microbiota
composition data of small intestinal biopsies and faecal samples of 70
treatment naïve subjects with metabolic syndrome (FATLOSE 1, AFFIRM, FATLOSE 2
study).

In this observational study we aim to compare the microbiota composition of
faeces via stool collection with the microbiota composition of the small
intestine via biopsies.

This is an observational single centre study. Healthy subjects routinely
planned for a gastrduodenoscopy at the department of Gastroenterology will keep
a dietary list 1 week before their intervention and collect their stool and
bring it on the day of gastroduodenoscopy. During gastroduodenoscopy 2 extra
biopsies will be obtained from the small intestine and 2 extra bloodsamples
(30ml) for determination of fasting glucose, insulin and lipid profiles will be
collected from the routinely placed venflon.

Subjects will visit the AMC twice. Once for a screening visit in which informed
consent will be signed and eligibility for the study screened. During the
second visit the routinely planned gastroscopy will be performed. On this day
subjects will bring a morning stool sample which will be stored for further
analysis. During gastroscopy small intestinal biopsies will be obtained which
will also be stored for further analysis. A gastroduodenoscopy is a very
frequently performed intervention at our department of Gastroenterology clinic
with a very low (<0.1%) complication rate. Although there is no direct benefit
for the volunteering subjects, this observational study will provide valuable
insight into the relationship between the microbiota composition of the small
intestine and faeces in health and disease. This will help improve diagnostic
methods for obesity and other metabolic disorders. Because subjects are to
receive a routinely planned gastroscopy we believe the added burden of this
study is very low and the results of this study outweigh the burden. Subjects
will receive 50 euro as compensation for their participation as well as
reimbursement of their travel expenses.