Contributions of light and transmission electron microscopy to the study of the human fat-storing cell

We examined the human fat-storing cell (Ito cell, lipocyte) in normal and pathologic liver biopsies using toluidine blue staining and transmission electron microscopy. We studied 5 normal patients, 6 non-alcoholic patients with liver steatosis, 8 patients with early alcoholic liver damage, 4 patients with extrahepatic cholestasis, 10 patients with chronic active hepatitis B (N = 2) or C (N = 8) with mild fibrosis, 5 patients with alcoholic cirrhosis and 4 with posthepatitic cirrhosis. We found that fat-storing cells were increased in patients with alcoholic steatofibrosis and extrahepatic cholestasis and decreased in cirrhotic patients. The mean number of lipid droplets per fat-storing cell was significantly increased in patients with alcoholic steatofibrosis. Transmission electron microscopy confirmed the light microscopic findings, especially the accumulation of lipid droplets in fat storing cells in early alcoholic liver disease. Sometimes lipid droplets with different electron density were noted. In cirrhosis there was a more prominent development of intracellular organelles, and cells often changed into a more elongated, myofibroblast-like shape.