Mast cell-Ito cell pairings found in the Disse's spaces in the liver of the beagle dog.

Ito cells (fat-storing cells), containing a few lipid droplets, appeared in the Disse's spaces of the Beagle dog liver. They ranged in diameter from 0.5 to 5 micron. The present study revealed that mast cells were also distributed in the Disse's spaces, while they were encountered only in the interlobular connective tissue in other animals. Although mast cells as well as Ito cells were distributed solitarily in the Disse's spaces, pairing of both types of cells could be frequently observed. Direct contact between both cells was verified using both light and electron microscopy. Also encountered were some peculiar figures of certain Kupffer cells engulfing the cytoplasmic processes and secretory granules of mast cells. These findings indicate a previously unknown intimate relationship between the mast cell and other perisinusoidal cells in the dog liver: the Ito cell, Kupffer cell and endothelial cell.