Nonalcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease in the United States and is the second most common reason for liver transplant.1 It is thought to be the hepatic consequence of systemic insulin resistance and the metabolic syndrome characterized by obesity, dyslipidemia, and type 2 diabetes mellitus. NAFLD has two subtypes: nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH).
NAFL is characterized by steatosis, including inflammation, in at least 5% of hepatocytes. NASH is defined by a constellation of features that include steatosis, lobular and portal inflammation, and liver cell injury in the form of hepatocyte ballooning.
Liver biopsy is the examination of tissues removed from the liver to find the presence, cause or spread of the disease. To detect any non-alcoholic fatty liver disease – NAFLD liver biopsy is a preferred tool.
The most common indications for performing a liver biopsy in patients with NAFLD is to confirm the diagnosis, diagnose other liver diseases, and to determine the damage to the liver and to further decide the treatment and prognosis. The last includes necroinflammatory activity grades, which is reversible and the collagen deposition which is also potentially reversible. By histologic evaluation, one is able to distinguish between NASH, a lesion with progressive potential, and no NASH, lesions without potential to progress.
We make extensive usage of liver biopsy in our In Vivo Amylin Liver NASH Models. There are different types of Liver Biopsy for NASH:
- Percutaneous- via a needle through the skin. Percutaneous liver is the most common type of Liver biopsy
- Transvenous – Through the blood vessels
- Endoscopical – ultrasound fine needle biopsy
- Other non-invasive methods
Data outcomes is benchmarked on histologic features which provide information regarding the effects of intervention on extent and severity of hepatocellular injury inflammation and architectural alterations as well as the ultimate diagnosis. Histologic evaluation remains the hard endpoint that can be measured with the high accuracy and more reliability. The most commonly used tool for histologic evaluation is the nonalcoholic fatty liver disease activity score (NAS). The NAS was not intended to replace the diagnosis but to provide a sensitive tool to assess the changes that might occur with or during the treatment. Importantly diagnosis of NASH was strongly associated with the presence of diabetes and quantitative insulin sensitivity check index (QUICKi) and homeostasis model assessment-estimated insulin resistance (HOMA-IR) while the diagnosis and the NAS both correlated with aminotransferases.
Nonalcoholic fatty liver disease activity score (NAS)
|5% – 33%||1|
|34% – 66%||2|