Non-alcoholic fatty liver disease
Non-alcoholic fatty liver disease (NAFLD) is accumulation of lipid within hepatocytes. Associated with obesity. Liver enzymes will be deranged, usually mildly. If associated with inflammation (or strictly speaking, ballooning degeneration), it is termed non-alcoholic steatohepatitis (NASH). Untreated, repeated inflammation and scarring can ultimately cirrhosis; indeed, some cases previously labelled as 'cryptogenic cirrhosis' are likely to have been due to NASH/NAFLD. Although the proportion of cases that progression from NAFLD to NASH to cirrhosis and ultimately to hepatocellular carcinoma (HCC) is relatively small, obesity is at epidemic levels in many Western and Middle Eastern countries, and a rise in the cases of HCC is predicted in several years.
The exact mechanisms of how obesity and lipid accumulation result in inflammation and damage is less clear, but it is thought that obesity results in changes in adipocyte function, which releases hormones, cytokines and other mediators that promote inflammation, or conversely, anti-inflammatory mediators are lowered, e.g. adiponectin levels with associated loss of its protective effect.
Several histological scoring systems exist. The Brunt-Kleiner score assesses steatosis, lobular inflammation and ballooning degeneration (with a separate fibrosis score). PTEN immunostaining is decreased compared to normal and alcoholic cirrhosis
- ↑ Davis GL, Roberts WL. The healthcare burden imposed by liver disease in aging Baby Boomers. Current gastroenterology reports. 2010 Feb; 12(1):1-6.(Link to article – subscription may be required.)
- ↑ Kleiner DE, Brunt EM, Van Natta M, Behling C, Contos MJ, Cummings OW, Ferrell LD, Liu YC, Torbenson MS, Unalp-Arida A, Yeh M, McCullough AJ, Sanyal AJ. Design and validation of a histological scoring system for nonalcoholic fatty liver disease. Hepatology (Baltimore, Md.). 2005 Jun; 41(6):1313-21.(Link to article – subscription may be required.)
- ↑ Sanchez-Pareja A, Clément S, Peyrou M, Spahr L, Negro F, Rubbia-Brandt L, Foti M. Phosphatase and tensin homolog is a differential diagnostic marker between nonalcoholic and alcoholic fatty liver disease. World journal of gastroenterology. 2016 Apr 14; 22(14):3735-45.(Link to article – subscription may be required.)