The ultrastructural pathology of five lipoprotein lipase-deficient cats

The ultrastructural pathology of cats suffering from familial lipoprotein lipase deficiency is described. There were large numbers of lipid vacuoles within hepatocytes, epithelial cells of the proximal convoluted tubule of kidney and macrophages of the liver, spleen and lymph node. The older cats tended to have larger quantities of ceroid within hepatocytes and macrophages, and all stages of development of ceroid were observed. Chylomicron emboli were seen within the glomerular capillaries and interlobular blood vessels. There was podocyte foot fusion and thickening of basement membranes of glomeruli, Bowman's capsule and some proximal convoluted tubules, similar to that seen in diabetes mellitus. These changes represent a non-specific reaction of the kidney to noxious insults such as hypoxia caused by emboli. Transformation of smooth muscle cells from a contractile to a synthetic state was seen in the splenic trabeculae and, to a lesser extent, in blood vessels. Dilatations of the nuclear membrane of the lymphocytes were noted, the significance of which is unknown.