Effect of cholecystectomy on hepatic fat accumulation and insulin resistance in non-obese Hispanic patients: a pilot study

Background: Nonalcoholic fatty liver disease (NAFLD) is highly prevalent worldwide. Experimental studies have shown that cholecystectomy (XGB) increases hepatic fat content in mice and appears associated to NAFLD in large retrospective population-based studies. The aim of this study was to prospectively assess the effects of XGB on hepatic fat content (HFC) and insulin resistance (IR) in non-obese, middle aged Hispanic subjects. Methods: Twenty-six gallstone patients undergoing elective XGB and 16 control subjects with normal livers and gallbladders at ultrasonography were prospectively followed 24 months for changes in HFC and IR. Clinical, biochemical determinations and hepatic imaging were performed at baseline and 24 months after surgery. MRI technique quantified HFC in four hepatic segments. IR was assessed by the Homeostasis Model Assessment (HOMA-(IR)) index. Results: Initial body mass index (BMI) was 25.6 +/- 0.4 and 24.3 +/- 1.0 in the control and XGB groups of subjects, respectively. Serum insulin level increased from 8.1 +/- 0.7 to 10.0 +/- 1.9 (mu U/ml) 24 months after surgery in XGB patients (p < 0.05); no significant changes were detected in control individuals. Median HOMA-IR index increased from 1.31 (interquartile range, 1.01-1.68) to 2.20 (interquartile range, 1.57-2.60) 24 months after XGB, (p < 0.003). Median HOMA-IR index of control subjects remained unchanged at the end of the study. Serum apoB concentration increased from 61. 5 +/- 3.4 to 79.0 +/- 7.8 (mu g/ml) in XGB patients (p < 0.03). Serum apoB levels remained within normal ranges in both periods of the study in control subjects. HFC significantly increased in 2 of the 4 segments 24 months after XGB: right posterior hepatic lobe (from 5.3 +/- 0.2% to 6.0 +/- 0.2%, p > 0.04) and right anterior hepatic lobe (from 5.8 +/- 0.2% to 6. 6 +/- 0.3%, p < 0.02). The average HFC of the four hepatic segments studied slightly increased from 5.4 +/- 0.2 to 5.8 +/- 0.3 2 years after XGB (p < 0.03). No significant changes were found in HFC in the control subjects at the end of the study. Conclusions: Elective XGB increases HFC, HOMA-IR index and serum apoB concentration. These results support the notion that XGB is a risk factor non-alcoholic fatty liver disease and other IR-associated disease conditions.