Effect antibiotics on gutmicrobiota composition & insulin resistance.

Objective:

To investigate the effect of antibiotic intervention on gut microbiota composition, insulin resistance and bile acid composition.



Study design:

Two-arm, randomised, controlled single centre trial.



Study Population:

Male obese subjects with metabolic syndrome (BMI > 30kg/m2, FPG>5.6 mmol/l), age 20-65 yr, no medication use.



Treatment:

Patients will be randomised to either 7 days amoxicillin 500mg 3dd or 7 days vancomycin 250 mg 3dd 2.



Outcome measures:

The primary endpoint is changes in faecal flora composition after 7 days as well as 2, 4 and 6 weeks after the antibiotics. Secondary endpoints are changes in insulin resistance (assessed by hyperinsulinemic normoglycemic clamp at baseline and after 7 days), bile acid and lipidmetabolism (assessed by mixed meal test at baseline and after 7 days), as well as changes in systemic inflammatory markers and lipid profiles at baseline as well as 7 days, 2, 4 and 6 weeks after antibiotics.



Sample Size:

It is estimated that a total of 10 patients in each arm are needed.

Accumulating data from both patients and animal models indicates that imbalances in the composition of the gut microbiota are related to obesity and its associated diseases However, the exact role of the microbiota and the mechanism mediating its impact on metabolic functions are poorly understood.

Interestingly, antibiotics have been shown to produce drastic short- and long-term alterations of the human indwelling microbiota. After a 2 wk intervention with norfloxacin in combination with ampicillin the numbers of aerobic and anaerobic gut bacteria in ob/ob mice were maximally suppressed. The ob/ob mice showed a significant improvement in fasting glycemia and oral glucose tolerance by 30%. Concomitant reduction of liver triglycerides, reduction of lipopolysaccharides supported the antidiabetic effects of antibiotic treatment. This study showed that modulation of gut microbiota with antibiotics improved glucose tolerance in mice by altering the expression of hepatic and intestinal genes involved in inflammation and metabolism.

The mechanism by with gutmicrobiota affect glucose metabolism remains elusive, however some studies have suggested that bileacids are involved in human glucose and lipid metabolism We postulate that insulin resistance can be reduced reducing the numbers of specific gut microbiota by certain antibiotics. To test this hypothesis, we would like to investigate the effect of antibiotic treatment on gut microbiota composition, insulin resistance and bile acid metabolism in obese subjects.

Baseline and 1,2,4 & 6 weeks after antibiotics.

Patients will be randomised to either 7 days amoxicillin 500mg 3dd or 7 days vancomycin 500mg 3dd.