Background and Aim:  Kupffer cell (KC) function and CD14 expression contributes to pathogenesis of non‐alcoholic steatohepatitis (NASH). However, these relationships remain unclear. We investigated the relationship of KC function with superparamagnetic iron oxide‐enhanced magnetic resonance imaging (SPIO‐MRI), histopathological severity of NASH, and number of CD14‐positive KCs in NASH.

Methods:  This retrospective study included 32 patients (24 with NASH and eight with simple steatosis) who had previously undergone SPIO‐MRI with T2‐weighted gradient‐recalled echo sequence. All subjects were diagnosed pathologically and were evaluated for necroinflammation grade, fibrosis stage, and number of CD14‐positive KCs. Patients with NASH and simple steatosis were compared by using the Mann–Whitney test to determine differences in percent reduction of liver‐to‐muscle signal intensity ratio (reduction‐%LMR), as a surrogate parameter of KC function, and number of CD14‐positive KCs. Kruskal–Wallis test and Pearson's correlation coefficient were used to analyze relation among reduction‐%LMR, histopathological severity and number of CD14‐positive KCs.

Results:  There were statistically significant differences in reduction‐%LMR and number of CD14‐positive KCs between NASH and simple steatosis patients (Mann–Whitney test, P < 0.001 for all comparisons). Reduction‐%LMR decreased with an increase in necroinflammation grade or fibrosis stage. The number of CD14‐positive KCs increased with an increase in necroinflammation grade and fibrosis stage (Kruskal–Wallis test, both, P < 0.001). A high correlation was seen between number of CD14‐positive KCs and reduction‐%LMR (Pearson r = 0.81; P < 0.001).

Conclusions:  KC phagocytic function evaluated with SPIO‐MRI correlated with histopathological severity and number of CD14‐positive KCs. These results support the concept that KC phagocytic dysfunction contributes to the pathogenesis of NASH.