Quantifying hepatic steatosis - more than meets the eye

Area of Science:

• Hepatology
• Histopathology
• Medical Imaging

Background:

• Non-alcoholic fatty liver disease (NAFLD) activity score (NAS) assesses disease severity.
• Accurate quantification of steatosis is crucial for NAS scoring.
• Steatosis contributes significantly to the NAS.

Purpose of the Study:

• To determine the optimal histological technique for identifying and quantifying liver steatosis.
• To compare the accuracy of different staining and analysis methods for steatosis assessment.
• To validate findings in both mouse models and human liver biopsies.

Main Methods:

• Assessed percentage steatosis and fat droplet size using H&E and ORO staining.
• Employed light microscopy and digital image analysis (DIA) for quantification.
• Compared histological results with biochemical triglyceride content and MRI assessments.

Main Results:

• H&E staining showed poor correlation with tissue triglyceride concentration.
• ORO DIA demonstrated high sensitivity and specificity for steatosis.
• ORO DIA strongly correlated with triglyceride content in mouse and human livers (R=0.706, P=0.001; R=0.894, P=0.041).
• MRI assessment of hepatic steatosis was found to be inaccurate.

Conclusions:

• Oil Red-O digital image analysis (ORO DIA) is the most accurate method for detecting and quantifying liver steatosis.
• ORO DIA offers a more robust approach for NAS scoring compared to H&E.
• While H&E-based NAS is clinically valid, ORO DIA enhances the precision of steatosis assessment.