Angiogenesis: a new surrogate histopathological marker is capable of differentiating between mild and significant portal hypertension.

AIM: Angiogenesis is considered an important pathophysiological feature of portal hypertension. We investigated the ability of angiogenesis, as CD34-positive microvessel density (MVD), to differentiate portal pressure in a CCl4-induced rat cirrhosis model.

METHODS

Cirrhosis was induced by intraperitoneal injection of carbon tetrachloride in 46 male adult Sprague-Dawley rats. A catheter connected to a highly sensitive pressure transducer was inserted into the portal vein to continuously record portal pressure. Fibrosis area, nodule size and MVD were assessed by image morphometry.

RESULTS

Of 42 rats in which portal pressure was measured successfully, 27 (64%) had portal pressure ≥10 mmHg, defined as significant portal hypertension. MVD was 4.5-fold higher and fibrosis area 13.0-fold higher in rats with significant portal hypertension than in rats with portal pressure <10 mmHg. Portal pressure was significantly correlated with MVD (r=0.491, p<0.001) and fibrosis area (r=0.545, p<0.001) in all animals, but only MVD correlated with portal pressure (r=0.731 p<0.001) in rats with significant portal hypertension. The area under receiver operating characteristic curve for MVD in all rats was 0.953 (95% CI: 0.875-1.031) and optimum cutoff for MVD was 18/mm², with 96.3% sensitivity and 93.3% specificity.

CONCLUSIONS

We found that MVD, measured by CD34 immunostaining, was better able than the fibrosis area to discriminate significant portal hypertension in rats, suggesting that MVD could be a surrogate marker for portal hypertension in patients with liver diseases.