What are the complications of NASH?
The complications of NASH include cirrhosis(also considered the last stage of NAFLD) and primary liver cancer(hepatocellular carcinoma, HCC).
The risk of developing cirrhosis in apatient with NASH is still uncertain and varies perhaps from 8% to 15%. Up tonow, very few studies have followed patients over sufficient periods of time toactually document the progression of NASH to cirrhosis. There is indirectevidence, however, that NASH can lead to cirrhosis For example, in somepatients, at the time of an initial diagnosis of NASH made by liver biopsy,cirrhosis is already present, along with the usual signs of NASH.四川省第四人民医院消化内科常玉英
Nonetheless, it is important to understandthat in most instances when cirrhosis develops, the fatty infiltrationdisappears (regresses) along with the inflammation. Cirrhosis in NASH with lossof fat and inflammation is referred to as burned-out cirrhosis. This situationmay result from less fat coming to the liver by way of the portal vein (thevessel that brings blood from the intestines to the liver). In addition, adecrease in insulin secretion (with the development of insulin dependent DM2)causes the triglyceride fats to leave the liver.
Furthermore, more and more reports indicatethat at least 50% of cases of cryptogenic cirrhosis (cirrhosis due tounidentified causes) occur in the setting of previous long-standing obesityand/or DM2. These observations suggest that insulin-resistance, hence NASH, wasoften the basis of what was called cryptogenic cirrhosis. In fact, the numberof liver transplantations for presumed NASH-related cirrhosis is on the rise.The high rate of recurrent NASH developing in the new livers of patients receivingliver transplants for cryptogenic cirrhosis further confirms the causal role ofNASH. Finally, a study from Francesuggests that patients with NASH have a similar risk of developing cirrhosis asdo patients with HCV. As indicated above, however, the progression to cirrhosisin NASH is thought to be slow and the cirrhosis diagnosis is typically made inpatients in their sixties.
There are also reports of primary livercancer (hepatocellular carcinoma, HCC) occurring in patients with NASH-relatedcirrhosis. Indeed, the incidence of HCC in NASH cirrhosis appears to be similarto that observed in HCV cirrhosis (1-2% per year). The process that causesliver cancer to form in NASH cirrhosis is unknown and has not yet been studied.HCC may develop as a result of liver repair and regrowth (hepatocellularregeneration) without any factor specifically related to NASH. Some authors,however, have suggested that insulin resistance in this situation may promotethe development of liver cancer.