An opportunistic pathogen isolated from the gut of
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An opportunistic pathogen isolated from the gut of an obese human causes obesity in germfree mice. The pathogen, Enterobacter cloacae B29, was isolated from a morbidly obese volunteer. When germfree mice were inoculated with B29 and fed a high fat diet, they developed significant insulin resistance, body weight gain, and other obesity characteristics. Mice fed B29 and a normal diet did not become obese. The findings suggest that overgrowth of an endotoxin producing gut bacterium can contribute to metabolic deteriorations in its human host.
An opportunistic pathogen isolated from the gut of
- 1. An opportunistic pathogen isolated from the gut of an obese human causes obesity in germfree mice Lisa Luna Medical Primary Care
- 2. Case • weight 174.8 kg, • body mass index 58.8 kgm2 • suffering from diabetes, hypertension and other serious metabolic deteriorations • on a diet composed of whole grains, traditional Chinese medicinal foods and prebiotics • lost 30.1 kg after 9 weeks, and 51.4 kg after 23 weeks • Amelioration of hyperinsulinemia, hyperglycemia and hypertension until most metabolic parameters improved to normal ranges
- 3. How does it happen? • Biomedical Indicator
- 4. Key Point----Enterobacter a genus of opportunistic, endotoxin producing Pathogens, made up 35% of the gut bacteria in a morbidly obese volunteer After 9 weeks on the WTP diet*, this Enterobacter population in the volunteer’s gut reduced to 1.8%, and became undetectable by the end of the 23-week trial *WTP Diet :whole grains, traditional Chinese medicine and prebiotics
- 5. Hypothesis The endotoxin producing Enterobacter population may have a causative role in the metabolic deteriorations of its human host
- 6. Animal Studies Animal: Germfree (GF) male C57BL/6J mice* *germfree mice are resistant to HFD-induced obesity Clinical isolation: • Strain Enterobacter cloacae B29 isolated from the volunteer’s gut • and nearest neighbor as E.cloacae subsp. cloacae ATCC 13047 Process: Inoculation of B29 and Luria–Bertani (LB) into GF mice Feed: • normal chow diet (NCD) or • High fat diet(HFD)
- 7. (continued) 4 groups: • NCD+B29 • NCD+LB • HFD+B29 • HFD+LB data collected at the end of 16 weeks after inoculation • Body weight • mass of epididymal, mesenteric, subcutaneous inguinal and retroperitoneal fat pad; • oral glucose tolerance test (OGTT) and areas under the curve (AUC) for the plasma glucose; • serum 2h post load insulin; • enzyme-linked immunosorbent assay (ELISA) analysis of serum LPS-binding protein (LBP); • serum amyloid A (SAA); • adiponectin corrected for bodyweight
- 8. Body weight after 16 weeks of experiment
- 9. Fat pad after 16 weeks of experiment
- 10. Blood Glucose level after 16 weeks of experiment
- 11. Conclusion from the data collected • The HFD+B29 gnotobiotic mice developed the most significant insulin resistant phenotype and body gain and other characteristics of obesity • The NCD+B29or NCD+LB both remained lean throughout the trial
- 12. Serum LPS-binding protein after 16 weeks *B29 was the only LPS producer in the gnotobiotic-mouse gut
- 13. Conclusion from the LBP level after 16 weeks experiment • The serum LPS-binding protein was significantly higher in the HFD+B29 gnotobiotic mice than in the NCD+B29 • increased serum–endotoxin load in the HFD+B29 gnotobiotic mice could only come from B29.
- 14. Serum SAA and adiponection level after the 16 weeks HFD+B29 mice had the greatest increase in systemic inflammation
- 15. Conclusion of the study Overgrowth of an endotoxin producing gut bacterium is a contributing factor to, rather than a consequence of, the metabolic deteriorations in its human host
- 16. Strength of the study • for the first time, established a gnotobiotic-mouse obesity model combining HFD with a human-originated endotoxin producer • identify more such obesity-inducing bacteria from various human populations • develop new strategies for reducing the devastating epidemic of metabolic diseases
- 17. Several question remains uncertain • Study is conducted for 16 weeks, it’s uncertain if the gut pathogen from the obese functions the similar way in a long term. • B29 is probably not the only contributor to human obesity in vivo. • More case study is required to replicate the experiments
- 18. Thank You! We Appreciate Your Patience