Deficient activity of hepatic acid lipase in cholesterol ester storage disease.

Absence of lysosomal acid lipase activity in the liver is described in cholesterol ester storage disease and Wolman's disease. This enzyme deficiency may result in the excess hepatic cholesterol ester found in both conditions. However, clinical, genetic, and histopathologic differences suggest that the two conditions are separate diseases not completely explained by deficient enzyme activity.

Phosphorylase kinase of the liver: deficiency in a girl with increased hepatic glycogen.

Studies of a child with glycogenosis revealed an increased concentration of glycogen and low phosphorylase activity in her liver. Using mixtures of homogenates of the patient's liver and of normal liver, we found the low phosphorylase activity to be caused by a deficiency of phosphorylase kinase and not of hepatic phosphorylase. The fact that phosphorylase activity was restored to normal values by the addition of phosphorylase b kinase from rabbit muscle substantiates this conclusion.

Deficient activity of dephosphophosphorylase kinase and accumulation of glycogen in the liver.

Low activity of phosphorylase and increased concentration of glycogen were found in liver tissue from five children with asymptomatic hepatomegaly. In vitro activation of liver phosphorylase in these patients occurred at the rate of 10% or less of normal. Elimination of the defect by the addition of kinase that activates phosphorylase demonstrated the integrity of the phosphorylase enzyme and the deficient activity of dephophophosphorylase kinase. On the average, 60% of the phosphorylase enzyme of normal human liver was in the active form. Phosphorylase kinase of rabbit muscle activated phosphorylase of normal human liver to a final value that was significantly higher than the one obtained in the absence of muscle phosphorylase kinase. The ultrastructural examination of hepatic tissue from the five patients revealed increased amounts of glycogen. There was scarcity of endoplasmic reticulum. There was intercellular glycogen in continuity with the glycogen of the hepatocytes through breaks in their circumference. Lipid droplets with lucid areas in the form of needles and plates contained aggregates of glycogen. There were numerous lysosomes, some containing glycogen. Large vacuoles filled with glycogen and surrounded by a membrane were seen occasionally. The vacuoles might reflect the lysosomal pathway of glycogen degradation, since there was apparent fusion of such autophagic vacuoles with small vesicles resembling primary lysosomes.

Brain ultrastructure in Reye's syndrome.

Cerebral biopsies were obtained for electron microscopy 48 and 72 hours after the onset of encephalopathy from a child with severe Reye's syndrome. Gravely ill at the time of craniectomy to relieve cerebral hypertension, the child survived and recovered good brain function; therefore, the biopsy findings appear to reflect the organelle pathology of the brain at a severe yet reversible stage in the disease process. The cardinal ultrastructural changes in the brain in Reye's syndrome are astrocyte swelling and partial deglycogenation, myelin bleb formation and universal injury of neuron mitochondria. The mitochondrial injury consists of matrix disruption with moderate but not massive swelling. Dilatation of rough endoplasmic reticulum and nuclear changes occurred only in neurons with severely altered mitochondria. The organelle pathology of the brain in this case did not resemble the organelle pathology of the brain in human "hepatic encephalopathy" or in experimental ammonia intoxication in primates. The mitochondrial ultrastructure of the cerebral neurons resembled the unique mitochondrial ultrastructural changes seen in the liver parenchyma in Reye's syndrome.

Brain ultrastructure in Reye's disease. II. Acute injury and recovery processes in three children.

Acute and recovery biopsies of three patients with Reye's Disease are described. Pleomorphic changes of neuronal mitochondria were identified in all of the acute biopsies, similar in appearance to the characteristic alterations of hepatic mitochondria. Distinctive myelin bleb formation may be directly attributable to the mitochondrial injury. The mitochondrial lesion is reversible. There is morphologic evidence for regeneration and repair of myelin; but the presence of myelin ovoids at long intervals after recovery indicates a loss of some myelinated fibers. The neuronal mitochondrial changes, pleomorphism with matrix expansion, and myelin bleb formation, reflect a specific biochemical injury be attributable to ischemic injury secondary to brain edema.

Fat nutrition and diet in childhood.

PIP: This paper discusses the nutritional requirements for fat in infants and children in the light of the dietary alterations recently proposed by the Inter-Society Commission on Heart Disease Resources. It is not well known what the requirement for total fat and for serum cholesterol level during the first year of life should be. It is known that the only proved requirement for fat is linoleic acid, and that a logical fat intake would be that supplied by breast milk. 80% of American infants are fed with formulas which are not supplemented with the essential vitamin E. After infancy fat requirements change, and body stores are sufficient to insure against fatty acid deficiency. The dietary intake of American children is high in quantities of saturated fats and cholesterol, possibly leading to atherosclerosis later in life. The question is whether this cholesterogenic diet is harmful to all Americans or to a limited number of clinically discernible subjects, i.e., those children genetically predisposed to hyperlipoproteinimia. Such predisposition could be diagnosed at birth by screening of the umbilical cord blood, and checked again at school age and at adolescence. Thus, although limitation of a cholesterogenic diet to prevent obesity is reasonable, restricting cholestrogenic foods in everyone for the unproved distant goal of reducing atherosclerosis is dubious.^ieng

Cholesterol ester storage disease and mesenteric lipodystrophy.

Cholesterol ester storage disease is a rare, inherited metabolic disorder of lipid associated with acid cholesteryl ester hydrolase deficiency. Thus far, 15 cases have been reported in the world literature. Reported here is the autopsy study of the oldest patient with this disease. The lipid storage occurred in the forms of birefringent needle-shaped crystals limited to hepatocytes and non-birefringent autofluorescent granules accumulated within the foam cells of the hepatic portal triads, duodenum, and ovaries. The cholesterol content of the liver was 16 times normal, primarily caused by increased cholesterol ester. Only trace cholesteryl ester hydrolase activity was demonstrated in the liver. An additional unique finding in our case was the presence of mesenteric lipodystrophy. Whether these two rare disorders observed in our patient represent unrelated conditions or have an etiologic association remains unknown.

Bile acid malabsorption--a consequence of terminal ileal dysfunction in protracted diarrhea of infancy.

Fecal excretion of labeled bile acid (14C-24-cholic acid) was distinctly increased in two infants with protracted diarrhea, whereas four patients with steatorrhea due to pancreatic or mucosal abnormalities and five patients with mild chronic diarrhea had no excess fecal loss of bile acid. The loss of 14C-24-cholic acid in our patients with intractable diarrhea was similar to that observed in four infants who had undergone ileal resection. The ratio of mean 24-hour excretion of bile acid to that of a non-absorbable marker, polyethylene glycol, confirmed the malabsorption of bile acid in the patients with intractable diarrhea or ileal resection. These results differ significantly (p less than 0.05) from excretion ratios obtained in patients with either steatorrhea or chronic diarrhea. The extent of the loss of bile acid was not significantly related to the rate of fecal fat excretion. There was no direct correlation of fecal weight with the rate of bile acid excretion. Ileal function, as further assessed by the Schilling test with exogenous intrinsic factor, was grossly abnormal in both of the patients with intractable diarrhea.