Relationship among histologic, radiologic, and biochemical assessments of hepatic steatosis: a study of human liver samples

Abstract

Background and aims: In patients with nonalcoholic fatty liver disease, there is not a consistent relationship between severity of steatosis and the presence of steatohepatitis. This leads to the possibility that severity of steatosis is not an important factor in the pathogenesis of nonalcoholic steatohepatitis. Alternatively, it is possible that currently used method to quantify hepatic steatosis (histologic grading) may not accurately reflect hepatic lipid content. Therefore, we examined the relationship between hepatic triglyceride (TG) content and nonbiochemical assessment of steatosis in 38 human liver samples.

Methods: Hepatic steatosis was histologically graded by the 3 hepatopathologists and hepatic TG levels were determined from liver homogenate. Additionally, we characterized the relationship between (a) hepatic steatosis quantified by magnetic resonance spectroscopy (MRS) and histologic grading and hepatic TG content and (b) hepatic long-chain polyunsaturated fatty acid n-6/n-3 ratio and the severity of steatosis.

Results: Twenty-two samples had <5% steatosis, 9 had 5% to 33% steatosis and 7 had >33% steatosis. The mean (+/-SD) hepatic TG was 1.8+/-1.3 mg/mg of protein and MRS fat score was 6.4+/-6.0. There was a significant correlation between histologic grading and hepatic TG content (r=0.64, P<0.001). A significant correlation existed between MRS fat score and histologic grading (r=0.61, P=0.006), and hepatic TG (r=0.63, P=0.004). Severity of steatosis as graded histologically had significant correlation with n-6/n-3 ratio (r=0.61, P<0.001).

Conclusions: Hepatic steatosis quantified by histologic grading or by MRS is significantly reflective of hepatic TG content. Further research is needed to investigate the relationship we observed between n-6/n-3 ratio and the severity of steatosis.