A morphometric study of the hepatic arterioles in end-stage primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is typified by a heterogeneous histology with periductal fibroinflammatory lesions. The hepatic arterioles in PSC have not been well characterized. Using image analysis, we sought to examine the dimensions of hepatic arterioles in PSC. We identified 30 livers from patients transplanted for PSC as well as 10 explants each from cirrhotic patients (serving as controls) having primary biliary cirrhosis, hepatitis C (HCV), and alcoholic liver disease. At least two representative hematoxylin and eosin-stained slides were selected, and ten cross-sectioned hepatic arterioles were photographed for image analysis. The vessels were measured at their longest span and width based on the outer portions of the tunica media. Wall thickness was measured at its thickest portion from the intima to the outer portion of the tunica media; the perimeter of the luminal area was outlined by the endothelial lining, generating the total luminal area. Mean arteriolar length, width, and wall thickness (p = 0.012, p = 0.004, p = 0.001, respectively) were greater in the PSC group; luminal area was similar between the groups. When compared to the individual sub-groups, wall thickness of arterioles in PSC remained significantly greater. End-stage PSC has even larger-sized arterioles and greater wall thickness as compared to that of other cirrhotic livers. This increased wall thickness found in PSC cannot be solely attributed to cirrhosis itself. These vessel changes may potentially be the result of, or contribute to, the pathogenesis of PSC.