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printer-friendly version| Fatty Liver Amelioration Through Bariatric Surgery by Philip Schauer, MD - November 2006 Nonalcoholic fatty liver disease (NAFLD) is found in the vast majority of obese adults and more than half of obese children. Early treatment of the condition is necessary to prevent progression to nonalcoholic hepatosteatitis, fibrosis, cirrhosis and end-stage liver failure or hepatocellular carcinoma. Fortunately, significant weight loss achieved through bariatric surgery can be an effective therapy for NAFLD.  Studies have shown bariatric surgery to be the most effective therapy for producing sustained weight loss in the morbidly obese. This can have a profound benefit on the reversal of steatosis and fibrosis, which likely occurs through the amelioration of comorbidities. Obese patients may have multiple comorbidities, including high rates of metabolic syndrome and diabetes. Metabolic syndrome is a constellation of factors encompassing abdominal obesity, atherogenic dyslipidemia, hypertension, insulin resistance, a prothrombotic state and a proinflammatory state. The diagnosis of metabolic syndrome is made on the presence of any three of these conditions.Patients with metabolic syndrome have high levels of oxidative stress, which is known to initiate the inflammatory cascade and cause hepatocellular injury. NAFLD is present in 60 percent of females and 30 percent of males with metabolic syndrome. The beneficial effects of weight loss on NAFLD appear to occur through improved insulin sensitivity. A sustained decrease in circulating glucose and insulin levels followed by the reduction in adipose mass and leptin levels likely reduce fatty infiltration and inflammation, thereby restoring insulin sensitivity. The result is the elimination of the fibrogenic tendencies of leptin, leading to reversal of fibrosis and cirrhosis. While nonsurgical weight loss with diet, exercise and behavior modification has traditionally been considered first-line treatment for NAFLD, significant weight loss with these methods is difficult to achieve and modest weight loss, when accomplished,is often difficult to maintain. Studies of weight loss achieved with pharmacotherapy disagree on its impact on NAFLD. Several studies have shown the positive benefit of surgical weight loss on NAFLD. In one single-center study, 70 patients diagnosed with NAFLD were evaluated extensively and screened for diabetes and the six conditions associated with metabolic syndrome before undergoing laparoscopic bariatric surgery. Intraoperative biopsies were taken, and repeat biopsies were performed postoperatively at a mean of 15 months. These were graded for steatosis, inflammation and fibrosis.Lab assessments of hyperlipidemia and liver function were also taken before and after weight loss for comparison. At the time of operation, 48 of the patients (70 percent) had metabolic syndrome and hypertension,and 35 (50 percent) had diabetes. The mean initial weight was 339 pounds. At the time of second biopsy, the mean weight had dropped to 236 pounds, an excess body weight loss of 59 percent. Major improvements were noted in the markers of metabolic syndrome, with marked improvement or resolution seen in most comorbid conditions. More than one-third of patients showed resolution of steatosis and inflammation, and 20 percent showed some or complete reversal of fibrosis. No patient experienced progression of abnormal liver morphology or deterioration of hepatic function. Sleeve gastrectomy and laparoscopic banding had less dramatic impacts on weight loss than gastric bypass. This correlated with a beneficial effect on liver morphology. These results highlight the important role that obesity, and by extension the metabolic syndrome,plays in the NAFLD disease process.  Dr. Philip Schauer is the Director of Advanced Laparoscopic and Bariatric Surgery at Cleveland Clinic and president of the American Society for Bariatric Surgery. In addition to bariatric surgery, his specialty interests include laparoscopic surgery, gastrointestinal surgery and colon surgery. A frequent national and international lecturer, Dr. Schauer also has published scores of articles on topics relating to bariatric and laparoscopic surgery, and his first textbook on this subject is due out in the summer of 2007, entitled ?Minimally Invasive Bariatric Surgery.? |
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