Characterization of hepatic steatosis in dogs with congenital portosystemic shunts

Abstract

Objective: To quantify the difference in fat percentage and lipid vesicle sizes between congenital portosystemic shunt (CPS) dogs and control dogs. To determine if there is any suggestion for macrovesicular steatosis to be associated with poor outcome following surgery. Study Design: Longitudinal prospective study. Animals: Ten dogs with CPS, one dog with multiple acquired portosystemic shunts, three healthy dogs. Methods: Wedge or punch biopsy samples were taken during surgery or necropsy, slices were stained with Oil Red O (ORO) staining. 5 randomly chosen fields were taken from each slide and graded for fat percentage, subdivided into classes of vesicle sizes and for lipogranulomas. Correlations between fat percentage, macrovesicular steatosis, outcome and age were statistically analyzed. Results: 6 out of 10 CPS dogs had an unfavorable outcome. Fat percentage in CPS dogs appeared higher (Mean=25.3, SD=20.1) when compared to healthy dogs (mean=3.2, SD=2.1) although this difference was not significant (p=0.06). There appeared to be a trend towards macrovesicular steatosis being associated with a high total fat percentage: 32% with macrovesicular steatosis, and 15% without macrovesicular steatosis. Conclusion: Fat percentage was quite abnormal in CPS dogs when compared to healthy dogs, although this difference was not significant. Using a larger number of dogs could solve this matter. All control dogs showed only small and evenly distributed fat vesicles. For CPS dogs there was broad range of fat percentage macro- or microvesicular steatosis and distribution. Fat percentage did not increase with age. A larger study has to be conducted to determine if macrovesicular steatosis predicts outcome after treatment of CPS. Clinical relevance: To determine if macrovesicular steatosis predicts outcome after treatment of CPS can be valuable to select treatment options.