Hepatic stellate cells and liver retinoid content in alcoholic liver disease in humans

Body retinoids are stored in the lipid droplets of hepatic stellate (Ito) cells. In chronic liver disease, the stellate cells differentiate into myofibroblast-like cells, a process whereby they lose their retinoid-containing lipid droplets. We studied the relation between liver retinoid content, the number of lipid droplets per stellate cell, and the number of stellate cells per mm2 in human alcoholic liver disease. Semithin sections of liver biopsies from normal subjects and patients with early (steatosis, inflammation, and mild fibrosis) and late (cirrhosis and cirrhosis with acute alcoholic hepatitis) alcoholic liver disease were morphometrically evaluated. Liver retinoid content was determined by HPLC. In normal patients, liver retinoid content was 901 +/- 213 IU/g of liver (mean +/- SEM). There was a decrease in liver retinoid content in early alcoholic liver disease (409 +/- 50 IU/g) and a further reduction in cirrhosis (153 +/- 50 IU/g). In patients with acute alcoholic hepatitis, retinoid content was strikingly low (5.2 +/- 1.8 IU/g). There was a progressive decrease in the number of stellate cells per mm2 associated with progressive liver damage. We found a fair correlation between the number of stellate cells per mm2 and liver retinoid content in all patient groups (overall correlation: 0.71). In normal subjects, the mean number of lipid droplets per stellate cell was 7.4 +/- 0.7. In patients with early alcoholic liver disease and in patients with alcoholic cirrhosis, this value was increased to 13.6 +/- 0.8 and 10.4 +/- 2.0, respectively. In patients with acute alcoholic hepatitis, only a few lipid droplets were present (4.2 +/- 0.5). There was a good correlation between liver retinoid content and mean number of lipid droplets in normal patients (r = 0.58). In alcoholic cirrhosis, however, correlation was poor (r = 0.34). In early alcoholic liver disease, the correlation was absent (r = 0.004). In conclusion, the major finding of our study is that the correlation between the mean number of lipid droplets per stellate cell and liver retinoid content varies according to the hepatic pathology considered. Marked lipid droplet accumulation occurs in stellate cells in early alcoholic liver disease and, to a lesser extent, in alcoholic cirrhosis, but there is no correlation between the mean number of lipid droplets per stellate cell and liver retinoid content. Therefore, not retinoids but probably lipids are responsible for the accumulation of lipid droplets. We also find that there is a fair correlation between the number of stellate cells per mm2 and liver retinoid content in all patient groups. Finally, we confirm the decrease in hepatic retinoid content that occurs in alcoholic liver disease in humans, even at the early stages of the disease.