Reduction of intestinal apo A-IV mRNA levels in the cirrhotic rat

In the present study, intestinal apo A-IV synthesis was investigated using a carbon tetrachloride (CCl₄)-induced cirrhosis rat model. Triglyceride (TG) content in rat cirrhotic liver was increased markedly by 170% (P< 0.001) and apo B was increased by 20% (P<0.05) compared with control levels. These results reflected the steatotic change in the liver. In contrast, TG levels in the small intestine of cirrhotic rats decreased significantly (P<0.01). In addition, intestinal apo A-IV (jejunum P< 0.001; ileum P< 0.01) and its mRNA levels (jejunum P< 0.01; ileum P< 0.05) were also reduced. The decreased apo A-IV content in the jejunum was confirmed by immunohistochemical analysis. These results indicate that intestinal apo A-IV synthesis in cirrhosis is suppressed, at least under the condition of an overnight fast. Therefore, decreased intestinal apo A-IV synthesis may relate to the decreased ability to absorb fat in cirrhosis, but a fat-loading study will be necessary to confirm this hypothesis. It is unknown from the present study why serum apo A-IV level is not significantly decreased, despite a reduction in apo A-IV synthesis. The clearance of apo A-IV by the liver may be delayed or apo A-IV synthesis may be rather markedly enhanced during fat absorption in liver cirrhosis.