New Theory Of Small Intestinal Bacteria Overgrowth In Nonalcoholic Fatty Liver Disease

Small intestinal bacterial overgrowth has been reported to play a role in the pathogenesis of NASH, endotoxin and TNF-A being the possible mediators. Contrary to this hypothesis, in another study, antibiotic treatment did not normalize aminotransferase levels in NASH patients. This article describes an animal experiment of NASH by Dr. Wan-Chun Wu et al.

Dr. Wan-Chun Wu et al* established a NASH animal model by a high fat diet for 12 wks successfully, and treated with cidomycin after 8 wks of the high fat diet. A semi-solid colored marker was used for monitoring small intestinal transit. The proximal small intestine was harvested under sterile condition and processed for quantitation for aerobes (E. coli) and anaerobes (Lactobacilli). Liver pathologic score was calculated to qualify the severity of hepatitis. Serum ALT and AST levels were detected to evaluate the severity of hepatitis.

After 12 wks, they had significant findings. Small intestinal transit was inhibited in NASH group. Rats treated with cidomycin had higher small intestine transit rate than rats in NASH group. The high fat diet resulted in quantitative alterations in the aerobes (E. coli) but not in the anaerobics (Lactobacill). There was an increase in the number of E. coli in the proximal small intestinal flora in NASH group than in control group. TNF-A concentration was significantly higher in NASH group than in control group. TNF-A concentration was lower in cidomycin group than in NASH group. Treatment with cidomycin showed its effect by significantly lowering serum ALT, AST and TNF-A levels of NASH rats. SIBO may decrease small intestinal movement in NASH rats. SIBO may be an important pathogenesis of Nash and treatment with cidomycin by mouth can alleviate the severity of NASH.

The results of this study suggest a promising future for many NASH patients. Due to the high disease incidence of NAFLD around the world and no effective treatment at present, this case reported by Dr. Wan-Chun Wu is surely worth the attention of both doctors and the public at large.

*Journal reference: Wu WC, Zhao W, Li S. Small intestinal bacteria overgrowth decreases small intestinal motility in the NASH rats. World J Gastroenterol 2008 January; 14(2):313-317  http://www.wjgnet.com/1007-9327/14/313.asp