When quantifying hepatic steatosis in different histological regions, steatosis distribution patterns differ between chronic hepatitis B patients with fatty liver (FL&CHB) and patients with nonalcoholic fatty liver disease (NAFLD), according to a study published in Annals of Hepatology.
In this cross-sectional study, researchers used the second-harmonic generation/2-photon excited fluorescence method to compare hepatic steatosis distribution patterns in patients with NAFLD (n=42), with FL&CHB (n=46), and without steatosis (n=55). Liver biopsy specimens were sectioned at 5 µm thickness and deparaffinized; fatty liver was defined as the presence of >5% steatosis.
The median percent of steatosis at periportal area was significantly lower than the percent of steatosis in the lobule area and percent of steatosis in the overall area in patients with NAFLD (P <.001). There was no obvious regional differences observed in the samples of patients with FL&CHB. Compared with the NAFLD group, the percent of steatosis overall was significantly lower in the FL&CHB group. The ratio of percent of steatosis at periportal area to steatosis in the lobule area was significantly higher in patients with FL&CHB compared with the NAFLD group (P <.05).
This study is limited by its cross-sectional design and small number of the study population. Causal inference of HBV could not be firmly established. Histology alteration pre- and post-antiviral therapy would make these findings more convincing, but the second biopsy is difficult to obtain given the ethical issues.
The researchers demonstrated that steatosis mainly occurs within lobule area in patients with NAFLD, and that this typical distribution pattern shifts significantly and the ratio of steatosis at periportal area to steatosis in the lobule area is significantly higher in patients with FL&CHB. “Differential steatosis distribution patterns are also seen between adult NAFLD and pediatric NAFLD,” the researchers said. “In adult NAFLD, steatosis [is] typically located in the pericentral region as demonstrated in our study. Comparing to adult NAFLD, pediatric NAFLD is predominantly zone 1 steatosis, which is close to portal tract. Cross study shows that this type of steatosis is associated with more advanced fibrosis. Whether this is the case for FL&CHB patients is not clear. It is worth to explore how steatosis affects the progression of (HBV) related fibrosis. Besides, whether this type of steatosis responses differently [sic] from typical adult NAFLD steatosis in treatment also needs to be further addressed.”
Zhuang Z, Qu H, Yang W, et al. Comparing hepatic steatosis distribution patterns between non-alcoholic fatty liver disease and fatty liver disease with chronic hepatitis B by second-harmonic generation/two-photon excited fluorescence method [published online December 3, 2019]. Ann Hepatol. doi: 10.1016/j.aohep.2019.11.003