An experimental study on the origin of foam cells in glomerulonephritis.

Masugi nephritis induced in cholesterol-fed rabbits is characterized by accumulation of foam cells in glomeruli which vary in number almost in parallel with the natural course of the disease. From electron microscopic appearances these foam cells are apparently derived from migrant blood monocytes and mesangial cells, but not from endothelial cells. Location of monocytic foam cells is extremely variable, though most often observed in the subendothelial space. In addition, monocytes undergo transformation into multinucleated giant cells including Touton type's. Lipid deposits filling the cytoplasm of foam cells seem to be in two forms, free cytoplasmic droplets and membrane-bounded structures partly containing membranous debris or myelin figures. The latter accumulates preferentially in the cytocentrum and is considered to originate from lysosomes. It seems unlikely that glomerular lesions in Masugi nephritis are aggravated by foam cell accumulation.