Pericanalicular microfilaments of hepatocytes in patients with familial non-hemolytic hyperbilirubinemia

We observed pericanalicular webs (PCW) of liver cells in cases with familial non-hemolytic hyperbilirubinemia using electron microscopy. The area and width of PCW were determined by morphometric methods as a way of quantitating this feature. The mean PCW width was 0.175±0.003 μm (mean ± SE) in Dubin-Johnson syndrome and 0.184±0.005 μ,m in Rotor’s syndrome. In both of these syndromes PCW width was significantly larger than that in Gilbert’s syndrome (0.124±0.003 /μm) (p<0.01). The mean PCW area was 0.585±0.017 /xm2 in Dubin-Johnson syndrome and 0.582±0.030/i,m2 in Rotor’s syndrome. Values in these two syndromes were significantly larger than that in Gilbert’s syndrome (0.382±0.014ju,m2) (p<0.01). Widths and areas of PCW in these three syndromes were not significantly different between central, intermediate, and peripheral zones of the hepatic lobules. There was a positive correlation between serum direct bilirubin levels and widths or areas of PCW in these syndromes. These results suggested that disturbances of bile flow caused by the dysfunction of pericanalicular microfilaments are partly involved in the pathogenesis of Dubin-Johnson syndrome and Rotor’s syndrome.