Morphometric analysis of lymphatic and blood vessels in human chronic viral liver diseases

The purpose of this study was to elucidate the morphometric changes occurring in hepatic lymphatics in human chronic viral liver diseases and to investigate the relationship between liver fibrosis, liver inflammation, and these changes. The lymphatic vessels were stained intensely by enzyme histochemistry for 5'-nucleotidase, whereas blood vessels stained well for alkaline phosphatase. We performed a morphometric analysis to estimate the number of lymphatic and blood vessels and their areas, using computer graphics software (NIH Image). Both the number of lymphatics in the specimens and their areas were increased according to the degree of liver fibrosis, but neither showed any relationship with the degree of activity of hepatitis. Neither the number nor the areas of the blood vessels showed any obvious relationship with the degree of fibrosis or the activity of chronic hepatitis. Correlation between clinical and laboratory data and the sizes and number of the lymphatics supported these morphological data. Our results clarified that the sizes and number of lymphatics are related to the stage of fibrosis in chronic viral liver diseases. This is thought to be due to increased lymph production, which is caused by the disturbance of the microcirculation associated with liver fibrosis.