Abnormal mitochondria in hepatocytes in human fatty liver.

Liver biopsies from fatty livers in thirty patients whose daily alcohol consumption was excessive, or they were in a diabetic state or overweight, and liver biopsies from seven control patients not presenting the above disorders, were studied by light microscopy 0.75 micronm EPON embedded, toluidine blue stained sections, and electron microscopy. Abnormal mitochondria were rarely found in normal liver tissue and, if present, they were found only in periportal hepatocytes. The frequency of hepatocytes containing abnormal mitochondria was significantly higher in fatty liver than in normal liver (p less than 0.01). These cells were usually localized periportally, practically never in the centre of the lobule (p less than 0.01). The occurrence of abnormal mitochondria was not correlated with the degree of steatosis, and the increase in number of abnormal mitochondria was equally high in alcoholists, diabetics, and overweight subjects. The ultrastructural appearance and the periportal localization suggest a hyperfunction of the mitochondria, which may prevent a development of steatosis in these areas.