Three-dimensional structural changes of hepatic sinusoids in cirrhosis providing an increase in vascular resistance of portal hypertension.

A quantitative topological analysis of the three-dimensional sinusoidal structure of five normal human livers and ten cirrhotic livers was performed with the aid of a computer system for reconstruction from serial tissue sections. The mean cycle rank (number of independent cycles) of the sinusoidal network in the examined tissue, 200 x 200 x 80 microns 3 in size, was 181.2 +/- 23.9 in the normal liver and 84.9 +/- 19.1 in the cirrhotic liver. There was a statistically significant difference between the two values (P < 0.001), while there was no significant difference in the sinusoidal volume of the same size tissue between the normal liver and cirrhotic liver. It was found therefore that the sinusoidal network of the cirrhotic liver was more sparsely and coarsely connected in three-dimensional space than that of the normal liver. In addition, there was no significant difference in the mean sinusoidal radius or in the distribution of 1/(radius)4 values between the normal liver and the cirrhotic liver. Resistance changes of the lattice sinusoidal model, where resistance of each sinusoidal branch is proportional only to its length, were then studied. In the lattice model analysis, the resistance between the two endpoints becomes larger as the cycle rank of the network model decreases. This fact suggests that in portal hypertension of cirrhosis the three-dimensional structural change of sinusoids, that is, decrease in the cycle rank, plays a role of increased vascular resistance within regenerative nodules.