At the Forefront of NASH Research
STAM(TM) contract services available in Stelic
Posted on 22nd Aug, 2011
The NAFLD activity score (NAS), proposed by the NASH Clinical Research Network*, is the most widely used scoring system in the field of NAFLD/NASH research [1].
NAS is defined as the unweighted sum of the histological scores for steatosis (0-3), lobular inflammation (0-3) and hepatocyte ballooning (0-2) (see Table), which represent active liver injury. NAS yields a total score from 0 to 8 and allows detailed analysis of histological changes for comparative and correlative studies in clinical and non-clinical trials.
NAS was originally developed for evaluation, but not for diagnosis of NAFLD/NASH. Nevertheless, the score has been frequently used for NASH diagnosis, with the NAS of 5 considered as a threshold. Although NAS shows good correlation with the diagnosis, careful interpretation must be required. There are the cases where non-NASH livers may score the total NAS of ≧5, or on the contrary, livers with NAS ≦4 may receive a diagnosis of NASH [2], [3].
In case of evaluation of drug efficacy, NAS is useful when applied strictly to histologically proven NASH patients. From the aspect of non-clinical studies, NAS should be carefully used when applied to animal model of uneven onset of NASH pathology.
Since Stelic's proprietary NASH-HCC model (STAM model) has uniform and reproducible [100%] disease progression, the STAM model is favorable for comparative studies using NAS.
* A network established in 2002 by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) to study the natural history of and conduct clinical trials for adult and pediatric fatty liver disease.
Key words: NAFLD, NASH, histopathological scoring system, NAFLD activity score
References
- Kleiner, DE., et al., (2005). Design and validation of a histological scoring system for nonalcoholic fatty liver disease. Hepatology, 41, 1313-21.
- Brunt, EM., et al., (2011). Nonalcoholic fatty liver disease (NAFLD) activity score and the histopathologic diagnosis in NAFLD: distinct clinicopathologic meanings. Hepatology, 53, 810-20.
- Hjelkrem, M., et al., (2011). Validation of the non-alcoholic fatty liver disease activity score. Aliment. Pharmacol. Ther., 34, 214-8.
