Steatocholecystitis: the influence of obesity and dietary carbohydrates

INTRODUCTION: We have recently demonstrated that obese and lean mice fed a high fat diet have increased gallbladder wall fat and decreased gallbladder contractility, cholecystosteatosis. Animal and human data also suggest that diets high in refined carbohydrates lead to gallstone formation. However, no data are available on the role of dietary carbohydrates on gallbladder wall fat and inflammation. Therefore, we tested the hypothesis that both obesity and dietary carbohydrates would increase gallbladder fat and cytokines, steatocholecystitis. METHODS: At 8 wk of age, 47 lean and 22 obese female mice were fed a 45% carbohydrate (CHO) diet while an equal number of lean and obese mice were fed a 75% CHO diet for 4 wk. All mice underwent cholecystectomy, and the gallbladders were snap-frozen. Individual and total lipids were measured by gas chromatography. Interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, and IL-6 were measured by enzyme-linked immunosorbent assay. Data were analyzed by analysis of variance and Tukey test. RESULTS: Gallbladder total fat, triglycerides, and cholesterol were maximum (P < 0.001) in obese mice on the 75% CHO diet. Gallbladder TNF-alpha and IL-1beta as well as serum cholesterol levels showed a similar pattern (P < 0.001). Gallbladder saturated free fatty acids and IL-6 levels were highest (P < 0.001) in obese mice on the 45% CHO diet. CONCLUSIONS: These data suggest that (1) both obesity and dietary carbohydrates increase gallbladder total fat, triglycerides, cholesterol, TNF-alpha, and IL-1beta and (2) obesity also increases gallbladder free fatty acids and IL-6. Therefore, we conclude that obesity is associated with steatocholecystitis and that a high carbohydrate diet exacerbates this phenomenon.