Lysosomal Acid Lipase Deficiency: Therapeutic Options.

Lysosomal acid lipase (LAL) deficiency is a metabolic (storage) disorder, encompassing a severe (Wolman disease) and attenuated (Cholesterol ester storage disease) subtype; both inherited as autosomal recessive traits. Cardinal clinical features include the combination of hepatic dysfunction and dyslipidemia, as a consequence of cholesteryl esters and triglyceride accumulation, predominately in the liver and vascular and reticuloendothelial system. Significant morbidity can arise, due to liver failure and/or atherosclerosis; in part related to the severity of the underlying gene defect and corresponding enzyme deficiency. Diagnosis is based on demonstration of decreased LAL enzyme activity, complemented by analysis of the cognate gene defects. Therapeutic options include dietary manipulation and the use of lipid-lowering drugs. Sebelipase alfa, a recombinant enzyme replacement therapy, has garnered regulatory approval, following demonstration of improvements in disease-relevant markers and clinical benefit in clinical trials, which included increased survival in the most severe cases.

Ezetimibe markedly attenuates hepatic cholesterol accumulation and improves liver function in the lysosomal acid lipase-deficient mouse, a model for cholesteryl ester storage disease.

Lysosomal acid lipase (LAL) plays a critical role in the intracellular handling of lipids by hydrolyzing cholesteryl esters (CE) and triacylglycerols (TAG) contained in newly internalized lipoproteins. In humans, mutations in the LAL gene result in cholesteryl ester storage disease (CESD), or in Wolman disease (WD) when the mutations cause complete loss of LAL activity. A rat model for WD and a mouse model for CESD have been described. In these studies we used LAL-deficient mice to investigate how modulating the amount of intestinally-derived cholesterol reaching the liver might impact its mass, cholesterol content, and function in this model. The main experiment tested if ezetimibe, a potent cholesterol absorption inhibitor, had any effect on CE accumulation in mice lacking LAL. In male Lal(-/-) mice given ezetimibe in their diet (20 mg/day/kg bw) for 4 weeks starting at 21 days of age, both liver mass and hepatic cholesterol concentration (mg/g) were reduced to the extent that whole-liver cholesterol content (mg/organ) in the treated mice (74.3±3.4) was only 56% of that in those not given ezetimibe (133.5±6.7). There was also a marked improvement in plasma alanine aminotransferase (ALT) activity. Thus, minimizing cholesterol absorption has a favorable impact on the liver in CESD.

Cholesteryl ester storage disease: protean presentations of lysosomal acid lipase deficiency.

OBJECTIVE: LIPA gene mutations result in deficiency of lysosomal acid lipase and present phenotypically as Wolman disease or cholesteryl ester storage disease (CESD) depending on the level of deficiency. Patients with CESD may often be misdiagnosed because symptoms may be nonspecific. Symptoms may present in infancy if there is complete loss of lysosomal acid lipase or in early childhood or adulthood when there is partial loss. The purpose of the present study is to review the literature for pediatric cases of CESD to better understand the phenotype of CESD. METHODS: A PubMed search of all English-language publications from 1966 through June 2012 for pediatric CESD case reports using the following key words CESD, fatty liver, and NAFLD was performed. All of the cases were reviewed and information regarding age, sex, presenting symptoms, and pertinent laboratory tests were recorded. RESULTS: Seventy-one cases were culled from 39 published case reports. Nearly two-thirds of these patients presented with their first symptoms when they were younger than 5 years. Hepatomegaly and splenomegaly were common features. Serum transaminases and lipids were often elevated. Gastrointestinal symptoms were noted in approximately one-third of cases. Two-thirds of patients had liver fibrosis. CONCLUSIONS: CESD has an estimated incidence as high as 1 in 40,000, which means that it is presently underdiagnosed. Education about common symptoms of CESD as well as a higher level of suspicion for screening for CESD will lead to earlier diagnosis. New treatments for CESD including possible enzyme replacement therapy make early diagnosis especially important.

Overexpression of lysosomal acid lipase and other proteins in atherosclerosis.

Atherosclerosis is one of the major causes of morbidity and mortality in the western world. The existing data of elevated expression levels of proteins like DNA damage and DNA repair enzymes in human atherosclerotic plaques are reviewed. From the literature, the effect of overexpression of different proteins using adenoviral vectors or the model of transgenic mice on the development of atherosclerosis will be discussed. Special focus is placed on the lysosomal acid lipase (LAL), because LAL connects extra-cellular with intra-cellular lipid metabolism and is the only hydrolase for cleavage of cholesteryl esters delivered to the lysosomes. Patients with a deficiency of LAL show an accumulation of lipids in the cells and develop pre-mature atherosclerosis. To answer the question of the influence of LAL in atherosclerosis if overexpressed, we show for the first time data of transgenic mice overexpressing LAL and the effect on the lipid level.

Subclinical course of cholesteryl ester storage disease in an adult with hypercholesterolemia, accelerated atherosclerosis, and liver cancer.

Few cases of asymptomatic cholesteryl ester storage disease (CESD) due to low enzymatic activity of human lysosomal acid lipase/cholesteryl ester hydrolase (hLAL) have been reported thus far in adults Here, we describe a 51-year-old man with a long clinical history of mixed hyperlipoproteinemia and severe premature atherosclerosis, but with no signs of hepatomegaly, liver dysfunction, or splenomegaly. The disease was discovered by chance in a biopsy performed because of suspected liver cancer (proven to be a cholangiocarcinoma). Residual hLAL activity in peripheral leukocytes was determined to be 6% of control values. DNA sequence and restriction fragment length polymorphism analysis demonstrated that the patient was a compound heterozygote for the prevalent CESD exon 8 splice site mutation (G934A) and the deletion of a C (nucleotide 673, 674, or 675) in exon 6 of the hLAL gene, resulting in premature termination of protein translation at residue 195. The patient died of liver failure as a consequence of extensive tumor infiltration at age 52. Lipid analysis revealed moderate cholesteryl ester storage in the liver and in the suprarenal cortex, and massive accumulation in the testicular histiocytes and Leydig cells, resulting in a pronounced secondary atrophy of the seminiferous tubules. Our case study demonstrates that hepatomegaly is an inconstant feature, even in CESD patients compound heterozygous for a Wolman mutation which results in complete loss of hLAL enzymic activity. It also highlights the need to be aware of this condition as it may be underdiagnosed.

[Acid lipase deficiency: Wolman disease and cholesteryl ester storage disease].

Wolman disease and cholesteryl ester storage disease (CESD) are caused by a deficiency of lysosomal acid lipase activity, resulting in massive accumulation of cholesteryl ester and triglycerides. Wolman disease occurs in infancy, with hepatosplenomegaly, steatorrhea and adrenal calcification. It is fatal before the age of 1 year. In CESD, hepatomegaly may be the only clinical abnormality, although lipid deposition is widespread. Lysosomal acid lipase hydrolyzes both triaclyglycerols and cholesteryl esters, and the enzyme plays an important role in the cellular processing of plasma lipoproteins, and contributes to homeostatic control of lipoprotein levels in blood and prevention of cellular lipid overloading. The gene encoding lysosomal acid lipase was cloned and characterized in 1994, and two mutations of acid lipase gene were found in a patient with Wolman disease, as a compound heterozygote. It is suggested that structural gene defects are also present in CESD cells. However, the reason (s) for the clinical difference between Wolman disease and CESD remain (s) to be studied.

Cholesterol ester storage disease: a reported case.

Cholesterol ester storage disease is a rare autosomal recessive disease which is characterized by accumulation of cholesterol esters and triglycerides in the hepatocytes and other tissues. A 5-year and 4-month old Thai female with hepatosplenomegaly and hypercholesterolemia was diagnosed to have this disease by light and electron microscopic studies of the liver tissue from open biopsy. Early diagnosis and treatment with appropriate drug can help the patient by delaying the consequent complications. Genetic counselling and simplified explanation of the disease are a benefit to the patient's family.

Increased hepatic secretion of very-low-density lipoprotein apolipoprotein B-100 in cholesteryl ester storage disease.

Using a stable isotope method, we measured the hepatic secretion rate of very-low-density lipoprotein apolipoprotein B-100 (VLDL apoB) in a 26-year-old women who had dyslipidemia due to cholesteryl ester storage disease (CESD) and in five normolipidemic subjects. [1-13C]Leucine was administered by a primed constant intravenous infusion and the enrichment of VLDL apoB was determined by gas chromatography-mass spectrometry. The absolute secretion rate (ASR) of VLDL apoB in the patient was more than twice the mean ASR of the normolipidemic group (17.1 vs 8.0 +/- 0.8 mg/kg body wt. per day). The plasma mevalonic acid concentration, a measure of intrahepatic cholesterol synthesis, was also greater in the patient than in the normolipidemic subjects (8.3 vs 4.4 +/- 1.8 micrograms/L). The findings are consistent with the hypothesis that in CESD increased intrahepatic synthesis of cholesterol stimulates hepatic secretion of VLDL apoB and this may partly account for the dyslipidemia.

Subclinical course of cholesterol ester storage disease (CESD) diagnosed in adulthood. Report on two cases with remarks on the nature of the liver storage process.

An extremely benign variant of cholesterol ester storage disease (CESD) was diagnosed in two female patients aged 43 and 56 years. In one of them the course was entirely subclinical until a stroke at the age of 47, most probably a complication of secondary hyperlipoproteinaemia. The diagnosis was made accidentally in vivo during extensive examination for concomitant monoclonal gammapathy. The other patient (aged 56), still displays a fairly stable course with minor dyspeptic symptoms. The clinical findings in both patients were confined to moderate well tolerated hepatomegaly, hyperlipoproteinaemia of IIb type and xanthelasmata. Acid lipase activity was markedly deficient in peripheral leukocytes and cultured fibroblasts. These cases represent a rare adult variant the existence of which should be borne in mind in the differential diagnosis of chronic liver disease in advanced age and of hyperlipoproteinaemic states. The diagnostic criteria for the routine clinicopathological steps are summarized with emphasis on a special lipopigment deposition pattern, encompassing inhibition and modification of lipofuscin generation in hepatocytes and an excess of ceroid production in both portal and intralobular histiocytes. The varied ultrastructural appearance of the lysosomal limiting membrane complex is described.

Cholesterylester storage disease: report of a case

A doença de depósito de ésteres de colesterol é uma doença familiar caracterizada pelo acúmulo de ésteres de colesterol e de triglicérides no figado, intestino e medula óssea. Até o momento, apenas 21 casos foram publicados. Apresenta-se uma menina de 9 meses de idade que procurou médico por um aumento do volume abdominal. Suas provas de funçäo hepática estavam normais e apresentava níveis séricos elevado de colesterol total e de triglicérides. A biopsia de fígado examinada com luz polarizada mostrou presença de muitos cristais de colesterol. Este é o paciente diagnosticado em mais jovem idade na literatura (excetuados os casos diagnosticados por autopsia)