The effects of bariatric surgeries on nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and is associated with obesity. Bariatric surgery has been shown to be the most effective method for weight reduction. However, no conclusive data exists on the effects of weight reduction surgery on NAFLD. This study aimed to characterize liver histology, metabolic status, and liver function changes in patients who underwent bariatric surgery, before and after the weight-reduction procedure. This is a phase 1 report of a prospective cohort study of patients who underwent bariatric surgery. Biopsies were obtained at baseline (intraoperatively) and 3 months postoperatively. Clinical characteristics, biochemical profile, and histopathological data [steatosis, NAFLD activity score (NAS), hepatocyte ballooning, lobular inflammation, and degree of fibrosis] were obtained at each time point. Twenty-seven patients were included (9 men and 18 women), and the median age was 35 ± 8 years old. At baseline, 3 patients had dyslipidemia, 4 had diabetes, and 5 patients had hypertension, which did not change at follow-up. The average body mass index decreased from 44.6 ± 7.8 to 34.2 ± 6.3 kg/m² at follow-up (P < 0.001). On histopathology, 12 of the 18 patients with preoperative steatosis (median score 2) had reduced steatosis scores postoperatively (P = 0.025); fibrosis (median score 1) was also reduced in 17 patients (P = 0.012), and NAS was decreased from 4 (3–5) to 2 (1–3) (P = 0.004). The changes in lobular inflammation and hepatocyte ballooning were not statistically significant on follow-up. The phase 1 results of this study described the histopathological changes following weight reduction surgery and suggested that hepatic steatosis, fibrosis, and NAFLD activity score were reduced 3 months after surgery. This clinical trial is financially supported by the National Plan for Science, Technology and Innovation Program grant number (11-MED1910-02).