The Effects of Bariatric Surgeries on Non-Alcoholic Fatty Liver Disease

Overview

Non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease. In the absence of chronic alcohol abuse or other liver diseases, NAFLD incorporates a wide spectrum of liver pathologies and is defined by fatty infiltration of the liver (simple hepatosteatosis). It can progress to non-alcoholic steatohepatitis (NASH) and later fibrosis, cirrhosis, and eventually some patients may develop hepatocellular carcinoma with or without cirrhosis. The exact cause of NAFLD is yet to be cleared and it is, therefore, an active area for research. The diagnosis of NAFLD is achieved through histological examination of liver biopsies (invasive), non-invasive markers using serum biomarkers and imaging techniques are still under development. Pathological diagnosis can be then subcategorized based on several scoring systems. More widely used are the Brunt Score or NAS (NAFLD activity score) and the Kleiner's modified NAS. Obesity is highly associated with NAFLD, as the epidemic of obesity has made NAFLD more prevalent. In addition insulin resistance has been linked to NAFLD and this is explained by the increased influx of free fatty acids (FFAs) into the liver. FFA undergoes either β-oxidation or esterification with glycerol to form triglycerides (TGs), resulting in an additional source of fat in the liver. Due to the strong association of NAFLD with obesity, weight reduction procedures are used for the management of NAFLD. In fact, this has been shown to be effective by several studies. However, other studies have reported liver deterioration after bariatric intervention. This conflict is what makes the effects of bariatric procedures a challenging field for further studies. Consequently in this study we are aimed to examine histologic, metabolic and liver function changes induced by the different therapeutic bariatric procedures.

35 consecutive patients referred for bariatric surgery will be recruited either at the obesity clinic, or from inpatient (scheduled for bariatric surgery). A detailed history and a complete physical examination will be done at the first visit along with anthropometric measures; routine blood tests, liver function, hormonal assessment, and certain metabolic and inflammatory markers will be evaluated. They will also have an abdominal ultrasound for initial NAFLD assessment, fibroscan to detect liver fibrosis, and an MRI to measure hepatic fat content and body fat composition including intra-abdominal and extra-abdominal fat. These patients will be asked to lose a certain amount of kilos (depending on their BMI and the surgeon preference) out of their original weight, in order to become candidates for bariatric surgery at King Saud University Hospital (KKUH). At the second visit, (if they lose the recommended amount weight) we will assess their weight loss; obtain blood for the same hormonal and inflammatory markers assessment. Nonetheless, if they did not lose weight and the treating surgeon gave them a third appointment, we will consider their third visit as a second visit; preforming all the investigations mentioned above. In this case we will interpret their results with respect to the total duration of "before surgery" weight loss. During the operation, tissue biopsy will be taken with a core needle biopsy for the liver and a sharp non-thermal instrument for subcutaneous fat, visceral fat, and abdominal muscle immediately after skin incision. A CAP certified tissue manager would process all tissues. Liver biopsy will be sliced it to two parts; the first half is for histological evaluation, but the other half will be stored for tissue studies. The histologic slides will be stained with hematoxylin and eosin (H\&E), and Masson Trichrome stains for microscopic evaluation. This evaluation will be provided by a single histopathologist who will be blinded to the patients' clinical condition, and the order of the biopsy. Follow Up: After the surgery follow up appointments will be scheduled 3 months, 6 months, 1 year, and annually till 5 years. The followings will be done in each visit: 1. Thorough physical exam as per the CRF. 2. Take a blood sample to evaluate liver function, metabolic, and inflammatory changes using the same parameters as those in the baseline. 3. Request for: fibroscan and abdominal ultrasound. Second, third and fourth liver biopsies will be taken percutaneously 3 months, 1 year, and 5 years following the initial biopsy respectively. These biopsies will be obtained using core tissue biopsy with ultrasound guidance for the same histological assessment and tissue studies. Another MRI will be schedule 1 year after the surgery. Specimens collected under this trial will be part of the King Saud University Liver Disease Research Centre Biobanking and will follow all policy and procedures within the biobanking protocol as approved by the IRB committee.