Lysosomal Acid Cholesteryl Esterase and Atherosclerosis in Cholesterol-Fed Rabbits

SummaryThe effect of high-protein pyridoxine-deficient diet on the localization of lysosomes and acid phosphatase activity in the rat liver was studied using light and electron microscopy. Numerous lysosomes con taining lipid droplets appeared to arise directly from GERI (Golgi apparatus, endoplasmic reticulum and lysosomes) near bile canaliculi and thereafter large crystal clefts were frequently found in these lysosomes. The increased appearance of lysosomes in hepatocytes was compatible with increased lipid droplets and represented an indication of breakdown of stored lipids. Acid phosphatase activity was localized almost exclusively in lysosomes with or without lipid droplets. We postulated that one of the causes of accumulation of lipid in hepatocytes, including that of tri glyceride and cholesteryl ester, might be associated with a relative deficiency of intralysosomal digestion in these conditions.

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“…28, No. 3,1982 mechanism similar to that postulated in an early stage of development of atherosclerosis (17).…”

Section: Discussionmentioning

confidence: 74%

Lysosomal changes in fatty liver induced in rats by high protein pyridoxine-deficient diet.

Kawaguchi

Abe

1982

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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“…This finding supports our previous suggestion that foam cells endocytize lipids accumulated in the extracellular space (Amanuma et al, submitted for publication). We reported previously that acid cholesterol esterase activity was reduced in low-density lysosomes that may contain a large amount of cholesterol ester (6,8). Possibly the endocytized lipids cannot be degraded because the acid cholesterol esterase activity of the lysosomes is reduced and thus the cells become foamy.…”

Section: Discussionmentioning

confidence: 98%

“…The cells isolated from rabbit atheromatous aorta consisted of smooth muscle cells and foam cells (7) and their lysosomal enzyme activities were increased in proportion to the severity of atherosclerosis (6,8).…”

mentioning

confidence: 99%

Cinemicrophotographic observation of aortic foam cells containing anisotropic lipid inclusions.

Takano

Amanuma-Muto

Imanaka

et al. 1984

Acta Histochem. Cytochem

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“…de Duve (9) and Takano et al (10) showed low cholesterol esterase activities of lysosomes in contrast with the high activity of the other lysosomal acid hydrolases in foam cells of smooth muscle cell origin. They supposed that cholesteryl esters accumulated in lysosomes of such cells because of an insufficiency of lysosomal ACE.…”

Section: Discussionmentioning

confidence: 99%

“…Another possibility is that the low titer of ACE activity represents endogenous substrate interferance by the cholesteryl esterrich lysosomes in the mature foam cells. Foam cells of atherosclerotic lesions have been shown to contain lysosomes of lower density due to high amounts of cholesteryl esters and free cholesterol; these low density lysosomes showed poorer ACE activities (9,10,20).…”

Section: Discussionmentioning

confidence: 99%

Acid Cholesterol Esterase Activity in the Foam Cells Isolated from Rabbit Experimental Xanthoma Tissues

Kodama

Nagao

Arakawa

et al. 1988

The Journal of Dermatology

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Acid cholesterol esterase (ACE) activity was assayed in the 10,000×g pellet from infiltrating cells isolated from experimental rabbit xanthoma tissues. Skin specimens were obtained from sites of intradermal dextran sulfate injections on a normolipemic rabbit (NLR) and a diet‐induced hypercholesterolemic rabbit (HCR). Most infiltrating cells were histiocytes or foam cells. Histiocytes from the NLR did not accumulate cholesteryl esters after the injections. Accumulation of cholesteryl esters in the xanthoma tissues of the HCR increased after repeating the injections at the same site. The ACE activity was greater in the cholesteryl ester‐accumulated foam cells than in histiocytes. The enzyme activity in the foam cells decreased during the developmental course of cholesteryl ester accumulation. These findings indicate that lysosomal ACE is activated and hydrolyzes the internalized cholesteryl esters of serum lipoprotein origin in the histiocytes which are transforming into foam cells. However, the enzyme activity decreases when too much of the cholesteryl esters has accumulated in the foam cells.

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Lysosomal Acid Cholesteryl Esterase and Atherosclerosis in Cholesterol-Fed Rabbits

Cited by 18 publications

References 22 publications

Lysosomal changes in fatty liver induced in rats by high protein pyridoxine-deficient diet.

Lysosomal changes in fatty liver induced in rats by high protein pyridoxine-deficient diet.

Cinemicrophotographic observation of aortic foam cells containing anisotropic lipid inclusions.

Acid Cholesterol Esterase Activity in the Foam Cells Isolated from Rabbit Experimental Xanthoma Tissues

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