Science.gov

Sample records for ischemia-induced cholesterol loading

  1. Cellular cholesterol efflux and cholesterol loading capacity of serum: effects of LDL-apheresis[S

    PubMed Central

    Adorni, M. P.; Zimetti, F.; Puntoni, M.; Bigazzi, F.; Sbrana, F.; Minichilli, F.; Bernini, F.; Ronda, N.; Favari, E.; Sampietro, T.

    2012-01-01

    High LDL-cholesterol (LDL-C) characterizes familial hypercholesterolemia (FH) and familial combined hyperlipidemia (FCH). LDL-apheresis, used in these patients to reduce LDL-C levels, has been shown to also affect HDL levels and composition. We studied LDL-apheresis effects on six FH and nine FCH subjects’ serum capacity to modulate cellular cholesterol efflux, an index of HDL functionality, and to load macrophages with cholesterol. Serum cholesterol efflux capacity (CEC) and macrophage cholesterol loading capacity (CLC) were measured before, immediately after, and two days after LDL-apheresis. The procedure reduced total cholesterol (TC), LDL-C, and apoB plasma levels (−69%, −80% and −74%, respectively), parameters only partially restored two days later. HDL-C and apoA-I plasma levels, reduced after LDL-apheresis (−27% and −16%, respectively), were restored to almost normal levels two days later. LDL-apheresis reduced serum aqueous diffusion (AD) CEC, SR-BI-CEC, and ABCA1-CEC. AD and SR-BI were fully restored whereas ABCA1-CEC remained low two days later. Sera immediately and two days after LDL-apheresis had a lower CLC than pre-LDL-apheresis sera. In conclusion, LDL-apheresis transiently reduces HDL-C levels and serum CEC, but it also reduces also serum capacity to deliver cholesterol to macrophages. Despite a potentially negative effect on HDL levels and composition, LDL-apheresis may counteract foam cells formation. PMID:22414482

  2. Differential lipid metabolism in monocytes and macrophages: influence of cholesterol loading[S

    PubMed Central

    Fernandez-Ruiz, Irene; Puchalska, Patrycja; Narasimhulu, Chandrakala Aluganti; Sengupta, Bhaswati; Parthasarathy, Sampath

    2016-01-01

    The influence of the hypercholesterolemia associated with atherosclerosis on monocytes is poorly understood. Monocytes are exposed to high concentrations of lipids, particularly cholesterol and lysophosphatidylcholine (lyso-PC). Indeed, in line with recent reports, we found that monocytes accumulate cholesteryl esters (CEs) in hypercholesterolemic mice, demonstrating the need for studies that analyze the effects of lipid accumulation on monocytes. Here we analyze the effects of cholesterol and lyso-PC loading in human monocytes and macrophages. We found that cholesterol acyltransferase and CE hydrolase activities are lower in monocytes. Monocytes also showed a different expression profile of cholesterol influx and efflux genes in response to lipid loading and a different pattern of lyso-PC metabolism. In monocytes, increased levels of CE slowed the conversion of lyso-PC into PC. Interestingly, although macrophages accumulated glycerophosphocholine, phosphocholine was the main water-soluble choline metabolite being generated in monocytes, suggesting a role for mono- and diacylglycerol in the chemoattractability of these cells. In summary, monocytes and macrophages show significant differences in lipid metabolism and gene expression profiles in response to lipid loading. These findings provide new insights into the mechanisms of atherosclerosis and suggest potentials for targeting monocyte chemotactic properties not only in atherosclerosis but also in other diseases. PMID:26839333

  3. Ischemia-induced endothelial cell dysfunction.

    PubMed

    Keep, R F; Andjelkovic, A V; Stamatovic, S M; Shakui, P; Ennis, S R

    2005-01-01

    Hemorrhagic transformation upon reperfusion therapy has focused attention on ischemia-induced endothelial dysfunction. This study examined whether hyperglycemia may induce hemorrhagic transformation by enhancing endothelial mitochondrial damage during ischemia and whether preconditioning (PC) stimuli may limit ischemia-induced endothelial damage. In vivo, rats received 2.8 M D-glucose or arabinose (1 ml/100 g; i.p.) prior to undergoing two hours of middle cerebral artery occlusion and transcardiac fixation for electron microscopy. In vitro, brain endothelial cells were exposed to a PC impulse (short-term oxygen glucose deprivation; OGD) prior to an injurious event (5 hours OGD). Endothelial injury was assessed by measuring lactate dehydrogenase release. Hyperglycemia during cerebral ischemia resulted in marked changes in endothelial morphology and mitochondrial swelling. Thus, in the ischemic hemisphere, there was no evidence of endothelial mitochondrial swelling in normoglycemic rats (mean profile width 0.22 +/- 0.04 vs. 0.17 +/- 0.01 microm in contralateral hemisphere) but there was marked swelling in hyperglycemic rats (0.44 +/- 0.02 microm). In vitro, cells preconditioned with one hour of OGD one day prior to 5 hours of OGD, showed reduced lactate dehydrogenase release (p < 0.05). In conclusion, hyperglycemia may have specific adverse effects on endothelial cell mitochondria during ischemia. Preventing those effects may help to ameliorate blood-brain barrier disruption on reperfusion. Insights into how to prevent endothelial injury may come from determining the mechanisms involved in endothelial preconditioning.

  4. Integrated late onset Alzheimer's disease (LOAD) susceptibility genes: Cholesterol metabolism and trafficking perspectives.

    PubMed

    Dong, Hee Kim; Gim, Jeong-An; Yeo, Seung Hyeon; Kim, Heui-Soo

    2017-01-15

    Late onset Alzheimer's disease (LOAD) is the most common type of dementia and is characterized by decreased amyloid-β (Aβ) clearance from the brain. Cholesterol regulates the production and clearance of Aβ. Genome-wide association study (GWAS) suggests that at least 20 genes are associated with LOAD. The genes APOE, CLU, SORL1, PICALM, and BIN1 have a relatively high LOAD susceptibility. Additional experimental and bioinformatic approaches to integrate data from genetics, epigenetics, and molecular networks may further increase our understanding of LOAD in relation to cholesterol metabolism and trafficking. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Cholesterol

    MedlinePlus

    ... from the food you eat (such as eggs, meats, and dairy products). Too much cholesterol can have ... fewer foods with saturated fats (such as red meat and most dairy products). Opt for healthier fats, ...

  6. Mitochondrial Cholesterol Loading Exacerbates Amyloid Beta Peptide-Induced Inflammation and Neurotoxicity

    PubMed Central

    Fernández, Anna; Llacuna, Laura; Fernández-Checa, José C.; Colell., Anna

    2009-01-01

    The role of cholesterol in Alzheimer's disease has been linked to the generation of toxic amyloid β peptides (Aβ). Using genetic mouse models of cholesterol loading, we examined whether mitochondrial cholesterol regulates Aβ neurotoxicity and AD pathology. Isolated mitochondria from brain or cortical neurons of transgenic mice overexpressing SREBP-2 (sterol regulatory element binding protein 2) or NPC1 (Niemann-Pick type C1) knockout mice exhibited mitochondrial cholesterol accumulation, mitochondrial GSH (mGSH) depletion and increased susceptibility to Aβ1-42-induced oxidative stress and release of apoptogenic proteins. Similar findings were observed in pharmacologically GSH-restricted rat brain mitochondria, while selective mGSH depletion sensitized human neuronal and glial cell lines to Aβ1-42-mediated cell death. Intracerebroventricular human Aβ delivery co-localized with mitochondria resulting in oxidative stress, neuroinflammation and neuronal damage that were enhanced in Tg-SREBP-2 mice and prevented upon mGSH recovery by GSH ethyl ester co-infusion, with a similar protection observed by i.p. administration of GSH ethyl ester. Finally, APP/PS1 mice, a transgenic AD mouse model, exhibited mitochondrial cholesterol loading and mGSH depletion. Thus, mitochondrial cholesterol accumulation emerges as a novel pathogenic factor in AD by modulating Aβ toxicity via mGSH regulation; strategies boosting the particular pool of mGSH may be of relevance to slow down disease progression. PMID:19458211

  7. Differential regulation of gene expression by LXRs in response to macrophage cholesterol loading.

    PubMed

    Ignatova, Irena D; Angdisen, Jerry; Moran, Erin; Schulman, Ira G

    2013-07-01

    The ability of cells to precisely control gene expression in response to intracellular and extracellular signals plays an important role in both normal physiology and in pathological settings. For instance, the accumulation of excess cholesterol by macrophages initiates a genetic response mediated by the liver X receptors (LXRs)-α (NR1H3) and LXRβ (NR1H2), which facilitates the transport of cholesterol out of cells to high-density lipoprotein particles. Studies using synthetic LXR agonists have also demonstrated that macrophage LXR activation simultaneously induces a second network of genes that promotes fatty acid and triglyceride synthesis that may support the detoxification of excess free cholesterol by storage in the ester form. We now show that treatment of human THP-1 macrophages with endogenous or synthetic LXR ligands stimulates both transcriptional and posttranscriptional pathways that result in the selective recruitment of the LXRα subtype to LXR-regulated promoters. Interestingly, when human or mouse macrophages are loaded with cholesterol under conditions that mimic the development of atherogenic macrophage foam cells, a selective LXR response is generated that induces genes mediating cholesterol transport but does not coordinately regulate genes involved in fatty acid synthesis. The gene-selective response to cholesterol loading occurs, even in the presence of LXRα binding to the promoter of the gene encoding the sterol regulatory element-binding protein-1c, the master transcriptional regulator of fatty acid synthesis. The ability of promoter bound LXRα to recruit RNA polymerase to the sterol regulatory element-binding protein-1c promoter, however, appears to be ligand selective.

  8. Differential Regulation of Gene Expression by LXRs in Response to Macrophage Cholesterol Loading

    PubMed Central

    Ignatova, Irena D.; Angdisen, Jerry; Moran, Erin

    2013-01-01

    The ability of cells to precisely control gene expression in response to intracellular and extracellular signals plays an important role in both normal physiology and in pathological settings. For instance, the accumulation of excess cholesterol by macrophages initiates a genetic response mediated by the liver X receptors (LXRs)-α (NR1H3) and LXRβ (NR1H2), which facilitates the transport of cholesterol out of cells to high-density lipoprotein particles. Studies using synthetic LXR agonists have also demonstrated that macrophage LXR activation simultaneously induces a second network of genes that promotes fatty acid and triglyceride synthesis that may support the detoxification of excess free cholesterol by storage in the ester form. We now show that treatment of human THP-1 macrophages with endogenous or synthetic LXR ligands stimulates both transcriptional and posttranscriptional pathways that result in the selective recruitment of the LXRα subtype to LXR-regulated promoters. Interestingly, when human or mouse macrophages are loaded with cholesterol under conditions that mimic the development of atherogenic macrophage foam cells, a selective LXR response is generated that induces genes mediating cholesterol transport but does not coordinately regulate genes involved in fatty acid synthesis. The gene-selective response to cholesterol loading occurs, even in the presence of LXRα binding to the promoter of the gene encoding the sterol regulatory element-binding protein-1c, the master transcriptional regulator of fatty acid synthesis. The ability of promoter bound LXRα to recruit RNA polymerase to the sterol regulatory element-binding protein-1c promoter, however, appears to be ligand selective. PMID:23686114

  9. Mitochondrial free cholesterol loading sensitizes to TNF- and Fas-mediated steatohepatitis.

    PubMed

    Marí, Montserrat; Caballero, Francisco; Colell, Anna; Morales, Albert; Caballeria, Juan; Fernandez, Anna; Enrich, Carlos; Fernandez-Checa, José C; García-Ruiz, Carmen

    2006-09-01

    The etiology of progression from steatosis to steatohepatitis (SH) remains unknown. Using nutritional and genetic models of hepatic steatosis, we show that free cholesterol (FC) loading, but not free fatty acids or triglycerides, sensitizes to TNF- and Fas-induced SH. FC distribution in endoplasmic reticulum (ER) and plasma membrane did not cause ER stress or alter TNF signaling. Rather, mitochondrial FC loading accounted for the hepatocellular sensitivity to TNF due to mitochondrial glutathione (mGSH) depletion. Selective mGSH depletion in primary hepatocytes recapitulated the susceptibility to TNF and Fas seen in FC-loaded hepatocytes; its repletion rescued FC-loaded livers from TNF-mediated SH. Moreover, hepatocytes from mice lacking NPC1, a late endosomal cholesterol trafficking protein, or from obese ob/ob mice, exhibited mitochondrial FC accumulation, mGSH depletion, and susceptibility to TNF. Thus, we propose a critical role for mitochondrial FC loading in precipitating SH, by sensitizing hepatocytes to TNF and Fas through mGSH depletion.

  10. Cholesterol-loaded cyclodextrin improves ram sperm cryoresistance in skim milk-extender.

    PubMed

    Salmon, Vianney M; Castonguay, François; Demers-Caron, Vincent; Leclerc, Pierre; Bailey, Janice L

    2017-02-01

    Cholesterol-loaded cyclodextrin (CLC) is known to improve ram sperm cryosurvival. This study expands on previous research to: (1) determine the mechanism by which CLC improves ram sperm cryosurvival and (2) compare the efficiency of a novel, skim milk-based extender containing CLC to a traditional egg yolk-based extender. Hypothesis #1 was that CLC enhances membrane cholesterol content to increase the resistance of ram sperm to cold and osmotic stress, thereby improving cryosurvival. We first assessed the ability of fresh sperm treated with CLC to withstand cold shock. Second, fresh sperm were treated with CLC to evaluate their tolerance to osmotic stress. Third, to confirm that cholesterol is incorporated into the sperm using CLC, we quantified sperm cholesterol. To test Hypothesis #2 that CLC is most effective in a medium without competing cholesterol, we compared sperm cryosurvival and fertility in skim milk-based extender containing CLC versus in a traditional egg yolk-based freezing extender without CLC. Our data confirmed that CLC treatment improves ram sperm cold shock and osmotic stress resistance, and augments sperm cholesterol content. Semen in skim milk-based extender containing CLC prior to freezing, had more motile sperm with intact acrosomes after thawing compared to semen in egg yolk-based extender. In contrast, sperm plasma membrane integrity and in vivo fertility of the semen cryopreserved in the skim milk-based extender with CLC did not differ from semen that was cryopreserved in egg yolk-based extender. Further research is warranted to combine CLC with other cryoprotection strategies or to modify the insemination protocol. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Treatment with cholesterol-loaded methyl-β-cyclodextrin increased the cholesterol in rabbit oocytes, but did not improve developmental competence of cryopreserved oocytes.

    PubMed

    Jiménez-Trigos, E; Vicente, J S; Mocé, E; Naturil-Alfonso, C; Fernandez-Gonzalez, R; Gutierrez-Adan, A; Marco-Jiménez, F

    2013-08-01

    Membrane cholesterol:phospholipids ratio is an important determinant of cell chilling sensitivity. At low temperatures, major membrane destabilisation occurs when the membrane undergoes a phase transition. To increase membrane fluidity and stability during cooling and thus increase oocyte cryoresistance, cholesterol has been added to the plasma membrane. This study was conducted to determine if cholesterol could be incorporated into rabbit oocytes by incubation with cholesterol-loaded methyl-β-cyclodextrin (CLC) and if added cholesterol could improve the developmental ability of cryopreserved oocytes after parthenogenetic activation or intracytoplasmic sperm injection. Fresh, frozen and vitrified oocytes incubated with CLC containing 20% NBD-labelled cholesterol (NBD-CLC) were evaluated using confocal microscopy. Fluorescence intensity was higher in fresh oocytes than in cryopreserved ones. Pre-treating rabbit oocytes with 1mg of NBD-CLC/mL did not improve cleavage and developmental rates after cryopreservation. Results showed that treatment with CLC increased the cytoplasmic cholesterol content, but did not improve cleavage rate and developmental competence of cryopreserved oocytes. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Reformulated meat products protect against ischemia-induced cardiac damage.

    PubMed

    Asensio-Lopez, M C; Lax, A; Sanchez-Mas, J; Avellaneda, A; Planes, J; Pascual-Figal, D A

    2016-02-01

    The protective effects of the antioxidants present in food are of great relevance for cardiovascular health. This study evaluates whether the extracts from reformulated meat products with a reduction in fat and/or sodium content exert a cardioprotective effect against ischemia-induced oxidative stress in cardiomyocytes, compared with non-meat foods. Ischemic damage caused loss of cell viability, increased reactive oxygen species and lipid peroxidation and decreased the antioxidant activity. Pretreatment for 24 h with digested or non-digested extracts from reformulated meat products led to protection against ischemia-induced oxidative damage: increased cell viability, reduced oxidative stress and restored the antioxidant activity. Similar results were obtained using extracts from tuna fish, but not with the extracts of green peas, salad or white beans. These results suggest that reformulated meat products have a beneficial impact in protecting cardiac cells against ischemia, and they may represent a source of natural antioxidants with benefits for cardiovascular health.

  13. Cholesterol-Loaded Cyclodextrin Increases the Cholesterol Content of Goat Sperm to Improve Cold and Osmotic Resistance and Maintain Sperm Function after Cryopreservation.

    PubMed

    Salmon, Vianney M; Leclerc, Pierre; Bailey, Janice L

    2016-04-01

    The success of semen cryopreservation depends on sperm membrane integrity and function after thawing. Cholesterol-loaded cyclodextrin (CLC) is used for in vitro incorporation of cholesterol to protect cells against cold temperatures. We hypothesized that CLC treatment also enhances sperm cholesterol content to increase tolerance to osmotic shock and cryoresistance, thereby improving fertility. We confirmed the fact that treatment of goat semen with 3 mg/ml CLC increases sperm cholesterol content using both the Liebermann-Burchard approach and filipin III labeling of membrane cholesterol. Sperm were then treated with or without CLC and cryopreserved. After thawing, sperm cholesterol dramatically fell, even in the presence of CLC, which explains the mechanism of cryocapacitation. CLC treatment, however, maintained a normal prefreeze cholesterol level in sperm after cryopreservation. Furthermore, fresh sperm treated with CLC and subjected to either cold shock or incubated in hypo-, iso-, and hyperosmotic media, designed to mimic stresses associated with freezing/thawing, displayed increased temperature and osmotic tolerance. CLC treatment also improved sperm viability, motility, and acrosome integrity after thawing. Furthermore, CLC treatment did not affect the sperm's ability to undergo in vitro capacitation according to chlortetracycline fluorescence and protein tyrosine phosphorylation. A pilot field trial demonstrated that artificial insemination with sperm that underwent increased cholesterol levels following CLC treatment yielded higher fertility ( ITALIC! P< 0.1) and proliferation ( ITALIC! P< 0.05) rates in vivo than untreated semen from the same ejaculate samples. These observations suggest that CLC treatment could be used to improve cryoprotection during the freezing and thawing of goat sperm.

  14. Dietary carbohydrates, glycemic load and serum high-density lipoprotein cholesterol concentrations among South Indian adults.

    PubMed

    Radhika, G; Ganesan, A; Sathya, R M; Sudha, V; Mohan, V

    2009-03-01

    To examine the relationship between dietary carbohydrates, glycemic load and high-density lipoprotein cholesterol (HDL-C) concentrations in Asian Indians, a high-risk group for diabetes and premature coronary artery disease. The study population comprised of 2043 individuals aged >/=20 years randomly selected from Chennai Urban Rural Epidemiological Study (CURES), an ongoing population-based study on a representative population of Chennai (formerly Madras) city in southern India. Participants with self-reported history of diabetes or heart disease or on drug therapy for dyslipidemia were excluded from the study. Dietary carbohydrates, glycemic index and glycemic load were assessed using a validated interviewer administered semiquantitative Food Frequency Questionnaire (FFQ). Both dietary glycemic load (P<0.0001) and total dietary carbohydrate intake (P<0.001) were significantly associated with higher serum triglyceride levels and lower serum HDL-C levels. For the lowest to highest quintile of glycemic load, the multivariate-adjusted mean HDL-C values were 44.1 mg per 100 ml and 41.2 mg per 100 ml (6.6% difference, P for trend<0.001), while for total carbohydrate it was less (5% difference, P for trend=0.016). The pattern of decrease in HDL-C for the lowest to highest quintile of glycemic load was more pronounced among men (1st vs 5th quintile: adjusted HDL-C: 4.3 mg per 100 ml decrease (10.3%)) than women (1st vs 5th quintile: adjusted HDL-C: 3.2 mg per 100 ml decrease (6.9%)). Our findings indicate that both total carbohydrates and dietary glycemic load intake are inversely associated with plasma HDL-C concentrations among Asian Indians, with dietary glycemic load having a stronger association.

  15. Effect of cholesterol-loaded cyclodextrins on cryosurvival of dog spermatozoa.

    PubMed

    Khan, J; Tahir, M Z; Khalid, A; Sattar, A; Ahmad, N

    2017-01-18

    Cryopreservation affects integrity of cholesterol and phospholipids in the plasma membrane of sperm leading to decreased fertility of frozen-thawed semen. Cholesterol-loaded cyclodextrins (CLC) have been shown to improve post-thaw semen quality in various species. The aim of this study was to investigate the optimal concentration of CLC for better post-thaw semen quality in dogs. Semen collection, through digital manipulation, was conducted once a week in four adult German shepherd dogs (n = 20 ejaculates; five ejaculates/dog). Semen samples with mass motility>3 (0: without movement; 5: fast progressive movement), motility >70% and concentration >200 × 10(6) /ml were pooled and processed in Tris-citrate extender containing 0, 1, 2 or 3 mg of CLC. The post-thaw quality was assessed on the basis of percentage motility, morphological abnormalities, live/dead ratio and plasma membrane, acrosome and DNA integrity, evaluated using anova and further analysed by Tukey's range test, if applicable. The addition of CLC showed an overall improvement in post-thaw semen quality. Among various treatment groups, and when compared to the control, the percentages of motile (55.5%), viable (65%), plasma membrane intact (56.7%), acrosome intact (49.2%) and DNA intact (98%) spermatozoa were significantly higher in 2 mg/ml CLC group (p < .05). It is concluded that incorporation of cholesterol in semen extender results in a beneficial increase in post-thaw semen quality in dogs.

  16. Response of boar sperm to the treatment with cholesterol-loaded cyclodextrins added prior to cryopreservation.

    PubMed

    Blanch, E; Tomás, C; Graham, J K; Mocé, E

    2012-12-01

    Cryopreserved boar sperm is not used extensively for artificial insemination, owing to the poor fertility rates of the sperm after freezing and thawing. The sperm membrane is damaged as the cells are cooled from body temperature to 5°C (cold shock), as well as during the freeze-thaw process. Increasing the cholesterol content of boar sperm membranes could help them survive cryopreservation, similar to sperm from other species that are cold shock sensitive. The aim of this study was to determine the optimal cholesterol-loaded cyclodextrin (CLC) concentration to use for boar sperm cryopreservation, and the influence of CLCs on the cryosurvival of sperm from boars classified as good or poor freezers. Treating boar sperm with 1 mg of CLC/120 × 10(6) sperm slightly improved (p < 0.05) the percentage of viable sperm after freezing-thawing. On the other hand, sperm, from both good and poor freezers, responded similarly to CLC treatment. Nevertheless, additional studies will be needed to study the effect of this treatment on other parameters of sperm quality.

  17. 20-HETE contributes to ischemia-induced angiogenesis.

    PubMed

    Chen, Li; Joseph, Gregory; Zhang, Frank F; Nguyen, Huyen; Jiang, Houli; Gotlinger, Katherine H; Falck, John R; Yang, Jing; Schwartzman, Michal L; Guo, Austin M

    2016-08-01

    Angiogenesis is an important adaptation for recovery from peripheral ischemia. Here, we determined whether 20-hydroxyeicosatetraenoic acid (20-HETE) contributes to ischemia-induced angiogenesis and assessed its underlying molecular and cellular mechanisms using a mouse hindlimb-ischemia angiogenesis model. Hindlimb blood flow was measured by Laser Doppler Perfusion Imaging and microvessel density was determined by CD31 and tomato lectin staining. We found that systemic and local administration of a 20-HETE synthesis inhibitor, DDMS, or a 20-HETE antagonist, 6,15-20-HEDGE significantly reduced blood flow recovery and microvessel formation in response to ischemia. 20-HETE production, measured by LC/MS/MS, was markedly increased in ischemic muscles (91±11 vs. 8±2pg/mg in controls), which was associated with prominent upregulation of the 20-HETE synthase, CYP4A12. Immunofluorescence co-localized increased CYP4A12 expression in response to ischemia to CD31-positive EC in the ischemic hindlimb microvessels. We further showed that ischemia increased HIF-1α, VEGF, and VEGFR2 expression in gracilis muscles and that these increases were negated by DDMS and 6,15-20-HEDGE. Lastly, we showed that ERK1/2 of MAPK is a component of 20-HETE regulated ischemic angiogenesis. Taken together, these data indicate that 20-HETE is a critical contributor of ischemia-induced angiogenesis in vivo. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Neuroprotective effect of geranylgeranylacetone against ischemia-induced retinal injury.

    PubMed

    Harada, Chikako; Nakamura, Kazuaki; Guo, Xiaoli; Kitaichi, Nobuyoshi; Mitamura, Yoshinori; Yoshida, Kazuhiko; Ohno, Shigeaki; Yoshida, Hiroshi; Harada, Takayuki

    2007-09-07

    This study was conducted to assess the effects of geranylgeranylacetone (GGA) on ischemia-induced retinal injury. Adult C57BL/6J mice were given oral treatments of GGA at 200 mg/kg daily for seven days. Ischemic retinal injury was carried out, and the extent of retinal cell death was quantitatively examined after 7 days. Immunohistochemistry for single-stranded DNA, phosphorylated form of p38 mitogen-activated protein kinase (p38 MAPK), and cleaved caspase-3 were performed one day after ischemic injury. In GGA-treated mice, we found the number of surviving retinal neurons was significantly increased compared with vehicle-treated mice. Ischemia-induced phosphorylation of p38 MAPK, which mediates apoptosis of retinal ganglion cells, was suppressed by GGA treatment. In such retinas, cleaved caspase-3- and single-stranded DNA-positive cells were also decreased compared with vehicle-treated mice. Oral GGA is a useful treatment for various retinal degenerative diseases that involve ischemic injury.

  19. Effect of cholesterol on the properties of spray-dried lysozyme-loaded liposomal powders.

    PubMed

    Charnvanich, Dusadee; Vardhanabhuti, Nontima; Kulvanich, Poj

    2010-06-01

    The influence of cholesterol (Chol) in the liposomal bilayer on the properties of inhalable protein-loaded liposomal powders prepared by spray-drying technique was investigated. Lysozyme (LSZ) was used as a model protein. Feed solution for spray drying was prepared by direct mixing of aqueous solution of LSZ with mannitol solution and empty liposome dispersions composed of hydrogenated phosphatidylcholine and Chol at various molar ratios. The spray-dried powders were characterized with respect to morphology, thermal property, and crystallinity using scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction, respectively. Most formulations gave slightly aggregated, spherical particles, and percentage yields of the spray-dried powders decreased with increasing Chol content. Degree of particle aggregation depended on the powder composition. The powders spontaneously formed liposomes which efficiently entrapped LSZ after reconstitution with HEPES buffered saline (HBS) at 37 degrees C. Lysozyme entrapment efficiency and size distribution of the reconstituted liposomes were evaluated after the powders were reconstituted with HBS. Increasing Chol content resulted in a decrease in size of the reconstituted liposomes and an increase in entrapment efficiency of LSZ. These results correlated with thermal behaviors of the reconstituted liposomes. Biological activity of LSZ was not affected by the spray-drying process. It was also demonstrated that LSZ-loaded liposomal powders could be produced without the need to preload the LSZ into liposomes prior to spray-drying process.

  20. Association of major histocompatibility complex II with cholesterol- and sphingolipid-rich membranes precedes peptide loading.

    PubMed

    Karacsonyi, Claudia; Knorr, Ruth; Fülbier, Angela; Lindner, Robert

    2004-08-13

    Major histocompatibility complex class II protein (MHC II) molecules present antigenic peptides to CD4-positive T-cells. Efficient T cell stimulation requires association of MHC II with membrane microdomains organized by cholesterol and glycosphingolipids or by tetraspanins. Using detergent extraction at 37 degrees C combined with a modified flotation assay, we investigated the sequence of events leading to the association of MHC II with cholesterol- and glycosphingolipid-rich membranes (DRMs) that are distinct from tetraspanins. We find two stages of association of MHC II with DRMs. In stage one, complexes of MHC II and invariant chain, a chaperone involved in MHC II transport, enter DRMs in the Golgi stack. In early endosomes, these complexes are almost quantitatively associated with DRMs. Upon transport to late endocytic compartments, MHC II-bound invariant chain is stepwise proteolyzed to the MHC class II-associated invariant chain peptide (CLIP) that remains MHC II-bound and retains a preference for DRMs. At the transition between the two stages, CLIP is exchanged against processed antigens, and the resulting MHC II-peptide complexes are transported to the cell surface. In the second stage, MHC II shows a lower overall association with DRMs. However, surface MHC II molecules occupied with peptides that induce resistance to denaturation by SDS are enriched in DRMs relative to SDS-sensitive MHC II-peptide complexes. Likewise, MHC II molecules loaded with long-lived processing products of hen-egg lysozyme containing the immunodominant epitope 48-61 show a very high preference for DRMs. Thus after an initial mainly intracellular stage of high DRM association, MHC II moves to a second stage in which its preference for DRMs is modulated by bound peptides.

  1. Placental Growth Factor Administration Abolishes Placental Ischemia-Induced Hypertension.

    PubMed

    Spradley, Frank T; Tan, Adelene Y; Joo, Woo S; Daniels, Garrett; Kussie, Paul; Karumanchi, S Ananth; Granger, Joey P

    2016-04-01

    Preeclampsia is a pregnancy-specific disorder of new-onset hypertension. Unfortunately, the most effective treatment is early delivery of the fetus and placenta. Placental ischemia appears central to the pathogenesis of preeclampsia because placental ischemia/hypoxia induced in animals by reduced uterine perfusion pressure (RUPP) or in humans stimulates release of hypertensive placental factors into the maternal circulation. The anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes and reduces bioavailable vascular endothelial growth factor and placental growth factor (PlGF), is elevated in RUPP rats and preeclampsia. Although PlGF and vascular endothelial growth factor are both natural ligands for sFlt-1, vascular endothelial growth factor also has high affinity to VEGFR2 (Flk-1) causing side effects like edema. PlGF is specific for sFlt-1. We tested the hypothesis that PlGF treatment reduces placental ischemia-induced hypertension by antagonizing sFlt-1 without adverse consequences to the mother or fetus. On gestational day 14, rats were randomized to 4 groups: normal pregnant or RUPP±infusion of recombinant human PlGF (180 μg/kg per day; AG31, a purified, recombinant human form of PlGF) for 5 days via intraperitoneal osmotic minipumps. On day 19, mean arterial blood pressure and plasma sFlt-1 were higher and glomerular filtration rate lower in RUPP than normal pregnant rats. Infusion of recombinant human PlGF abolished these changes seen with RUPP along with reducing oxidative stress. These data indicate that the increased sFlt-1 and reduced PlGF resulting from placental ischemia contribute to maternal hypertension. Our novel finding that recombinant human PlGF abolishes placental ischemia-induced hypertension, without major adverse consequences, suggests a strong therapeutic potential for this growth factor in preeclampsia. © 2016 American Heart Association, Inc.

  2. PLACENTAL GROWTH FACTOR ADMINISTRATION ABOLISHES PLACENTAL ISCHEMIA-INDUCED HYPERTENSION

    PubMed Central

    Spradley, Frank T.; Tan, Adelene Y.; Joo, Woo S.; Daniels, Garrett; Kussie, Paul; Karumanchi, S. Ananth; Granger, Joey P.

    2016-01-01

    Preeclampsia is a pregnancy-specific disorder of new-onset hypertension. Unfortunately, the most effective treatment is early delivery of the fetus and placenta. Placental ischemia appears central to the pathogenesis of preeclampsia as placental ischemia/hypoxia induced in animals by reduced uterine perfusion pressure (RUPP) or in humans stimulates release of hypertensive placental factors into the maternal circulation. The anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes and reduces bioavailable vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), is elevated in RUPP rats and preeclampsia. Although PlGF and VEGF are both natural ligands for sFlt-1, VEGF also has high affinity to VEGFR2 (Flk-1) causing side effects like edema. PlGF is specific for sFlt-1. We tested the hypothesis that PlGF treatment reduces placental ischemia-induced hypertension by antagonizing sFlt-1 without adverse consequences to the mother or fetus. On gestational day 14, rats were randomized to four groups: normal pregnant (NP) or RUPP ± infusion of rhPlGF (180 μg/kg/day; AG31, a purified, recombinant human form of PlGF) for 5 days via intraperitoneal osmotic minipumps. On day 19, mean arterial blood pressure and plasma sFlt-1 were higher and glomerular filtration rate lower in RUPP than NP rats. Infusion of rhPlGF abolished these changes seen with RUPP along with reducing oxidative stress. These data indicate that the increased sFlt-1 and reduced PlGF resulting from placental ischemia contribute to maternal hypertension. Our novel finding that rhPlGF abolishes placental ischemia-induced hypertension, without major adverse consequences, suggests a strong therapeutic potential for this growth factor in preeclampsia. PMID:26831193

  3. Effect of cholesterol-loaded-cyclodextrin on sperm viability and acrosome reaction in boar semen cryopreservation.

    PubMed

    Lee, Yong-Seung; Lee, Seunghyung; Lee, Sang-Hee; Yang, Boo-Keun; Park, Choon-Keun

    2015-08-01

    This study was undertaken to examine the effect of cholesterol-loaded-cyclodextrin (CLC) on boar sperm viability and spermatozoa cryosurvival during boar semen cryopreservation, and methyl-β-cyclodextrin (MBCD) was treated for comparing with CLC. Boar semen treated with CLC and MBCD before freezing process to monitor the effect on survival and capacitation status by flow cytometry with appropriate fluorescent probes. Sperm viability was higher in 1.5mg CLC-treated sperm (76.9±1.01%, P<0.05) than un-treated and MBCD-treated sperm before cryopreservation (58.7±1.31% and 60.3±0.31%, respectively). For CTC patterns, F-pattern was higher in CLC treated sperm than MBCD-treated sperm, for B-pattern was higher in CLC-treated sperm than fresh sperm (P<0.05). For AR pattern (an acrosome-reacted sperm) was lower in CLC-treated sperm than MBCD-treated sperm (P<0.05). Moreover, we examined in vitro development of porcine oocytes after in vitro fertilization using CLC-treated frozen-thawed semen, in which CLC treatment prior to freezing and thawing increased the development of oocytes to blastocyst stage in vitro. In conclusion, CLC could protect the viability of spermatozoa from cryodamage prior to cryopreservation in boar semen.

  4. Addition of cholesterol-loaded cyclodextrins to the thawing extender: effects on boar sperm quality.

    PubMed

    Tomás, C; Gómez-Fernández, J; Gómez-Izquierdo, E; Mocé, E; de Mercado, E

    2014-06-01

    The aim of the present study was to evaluate the effect that the addition of cholesterol-loaded cyclodextrins (CLC) to the thawing extender has on the quality of frozen-thawed boar sperm. Pooled semen (n = 5) from three boars was used for the experiments. The semen was cryopreserved with an egg-yolk-based extender, it was diluted after thawing in Beltsville thawing solution (BTS) supplemented with different concentrations of CLC (0, 12.5, 25, 50 or 100 mg/500 × 10(6) sperm), and these samples were incubated at 37°C for 150 min. The following parameters of sperm quality were evaluated 30 and 150 min after incubation: sperm with intact plasma membrane (SIPM; %), sperm with normal acrosomal ridge (NAR; %), total motile sperm (TMS; %), progressively motile sperm (PMS; %) and kinetic parameters. Both SIPM and NAR increased (p < 0.05) when the thawing extender was supplemented with 12.5, 25 and 50 mg CLC/500 × 10(6) sperm. Nevertheless, motility decreased (p < 0.05) when the concentration of CLC exceeded 12.5 mg CLC/500 × 10(6) sperm. In conclusion, our results suggest that the supplementation of thawing extenders with CLC improves sperm viability and reduces acrosome damage after freezing/thawing.

  5. Development of lycopene-loaded nanostructured lipid carriers: effect of rice oil and cholesterol.

    PubMed

    Riangjanapatee, P; Müller, R H; Keck, C M; Okonogi, S

    2013-09-01

    Nanostructured lipid carriers (NLC) were developed using a skin-compatible surfactant and natural lipid materials (rice oil, cholesterol) to incorporate lycopene. Characteristics of the NLC were explored in comparison with nanoemulsions and solid-lipid nanoparticles (SLN). Photon correlation spectroscopy, laser diffractometry (LD) and differential scanning calorimetry were used to determine particle size and thermal stability. Particle size expressed as LD (0.99) was 405 nm for the SLN, 350 nm for the NLC without cholesterol and 287 nm for the NLC with cholesterol. Rice oil and cholesterol enabled the formation of smaller particles, but cholesterol also reduced drug stability in the NLC. To preserve chemical stability of lycopene in the NLC, cholesterol should be avoided and storage should be at 4 degrees C or at room temperature.

  6. Supplementing rooster sperm with Cholesterol-Loaded-Cyclodextrin improves fertility after cryopreservation.

    PubMed

    Chuaychu-Noo, Napapach; Thananurak, Pachara; Chankitisakul, Vibantita; Vongpralub, Thevin

    2017-02-01

    Little is known about the effects of Cholesterol-Loaded Cyclodextrin (CLC) on post-thaw semen quality in chicken. The aim of the present study is to investigate the efficacy of CLC levels (0, 1, 2 and 3 mg/mL Schramm diluent) on post-thawed semen quality and fertility in two breeds of chicken Pradu Hang Dum (native chicken) and Rhode Island Red. Semen samples of each breed were pooled, divided into 4 aliquots and diluted with Schramm diluents, cooled to 5 °C when DMF was added (6% of final volume). Semen straws were subjected to cryopreservation using the liquid nitrogen vapor method. Post-thawed sperm motility, viability, acrosome integrity, mitochondrial function, and the Malondialdehyde (MDA) level were determined. The fertility of frozen semen was tested by inseminating laying hens. Post-thaw motility between Pradu Hang Dum and Rhode Island Red was no different; but Rhode Island Red had a higher semen viability and live cell intact acrosomes than Pradu Hang Dum (P < 0.05). The percentage of high functioning mitochondria in the Pradu Hang Dum was higher than the Rhode Island Red. CLC at 2 and 3 mg/mL supplementation was associated with improved viability of frozen semen; that is, acrosome integrity and mitochondrial function (P < 0.01), albeit having no effect on MDA levels. The sperm with 1 mg/mL CLC yielded a significantly better fertility (P < 0.01). CLC (1 mg/mL) improved the quality of frozen rooster semen. There was no interaction among breeds and CLC on post-thaw semen quality and fertility. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Novel technical strategies to optimize cryopreservation of goat semen using cholesterol-loaded cyclodextrin.

    PubMed

    Salmon, Vianney M; Leclerc, Pierre; Bailey, Janice L

    2017-02-01

    Artificial insemination is well-established in dairy cattle, with sires housed in commercial studs for processing. In some species, however, sires located on-farm are used for artificial insemination by shipping their semen to an off-site laboratory for processing within 24 h of collection. To expedite semen transport from the farm to laboratory, protocols must be uncomplicated. For goat semen, an obstacle is the seminal plasma, which must be removed because it contains proteins that impede sperm quality. Our objective is to develop a simple strategy to transiently store goat semen for 24 h prior to freezing. Cholesterol-loaded cyclodextrin (CLC) has been demonstrated to improve sperm tolerance to cryopreservation. Therefore, we hypothesized that CLC improves goat sperm resistance to seminal plasma damage, over 24 h prior to cryopreservation. We first evaluated the ability of CLC to protect goat sperm against seminal plasma damage by treating fresh semen with or without seminal plasma prior to cryopreservation. Second, fresh goat semen with seminal plasma was extended in skim milk-based extender ± CLC and held for 24 h at 5 °C prior to freezing. Our results indicate that CLC treatment improves goat sperm resistance to seminal plasma-mediated injury and protects sperm quality over 24 h prior to freezing (P < 0.05). Although the in vivo fertility of semen must first be assessed, it is possible that protocols for goat semen cryopreservation can be simplified by including CLC and eliminating seminal plasma removal. Processing and distribution of goat semen for AI would thereby be facilitated. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. ASMASE IS REQUIRED FOR CHRONIC ALCOHOL INDUCED HEPATIC ENDOPLASMIC RETICULUM STRESS AND MITOCHONDRIAL CHOLESTEROL LOADING

    PubMed Central

    Fernandez, Anna; Matias, Núria; Fucho, Raquel; Ribas, Vicente; Von Montfort, Claudia; Nuño, Natalia; Baulies, Anna; Martinez, Laura; Tarrats, Núria; Mari, Montserrat; Colell, Anna; Morales, Albert; Dubuquoy, Laurent; Mathurin, Philippe; Bataller, Ramón; Caballeria, Joan; Elena, Montserrat; Balsinde, Jesus; Kaplowitz, Neil; Garcia-Ruiz, Carmen; Fernandez-Checa, Jose C.

    2013-01-01

    Background & aims The pathogenesis of alcohol-induced liver disease (ALD) is poorly understood. Here, we examined the role of acid sphingomyelinase (ASMase) in alcohol induced hepatic endoplasmic reticulum (ER) stress, a key mechanism of ALD Methods We examined ER stress, lipogenesis, hyperhomocysteinemia, mitochondrial cholesterol (mChol) trafficking and susceptibility to LPS and concanavalin-A in ASMase−/− mice fed alcohol. Results Alcohol feeding increased SREBP-1c, DGAT-2 and FAS mRNA in ASMase+/+ but not in ASMase−/− mice. Compared to ASMase+/+ mice, ASMase−/− mice exhibited decreased expression of ER stress markers induced by alcohol, but the level of tunicamycin-mediated upregulation of ER stress markers and steatosis was similar in both types of mice. The increase in homocysteine levels induced by alcohol feeding was comparable in both ASMase+/+ mice and ASMase−/− mice. Exogenous ASMase, but not neutral SMase, induced ER stress by perturbing ER Ca2+ homeostasis. Moreover, alcohol-induced mChol loading and StARD1 overexpression were blunted in ASMase−/− mice. Tunicamycin upregulated StARD1 expression and this outcome was abrogated by tauroursodeoxycholic acid. Alcohol-induced liver injury and sensitization to LPS and concanavalin-A were prevented in ASMase−/− mice. These effects were reproduced in alcohol-fed TNFR1/R2−/− mice. Moreover, ASMase does not impair hepatic regeneration following partial hepatectomy. Of relevance, liver samples from patients with alcoholic hepatitis exhibited increased expression of ASMase, StARD1 and ER stress markers. Conclusion Our data indicate that ASMase is critical for alcohol-induced ER stress, and provide a rationale for further clinical investigation in ALD. PMID:23707365

  9. Transcriptome Analysis of Genes Regulated by Cholesterol Loading in Two Strains of Mouse Macrophages Associates Lysosome Pathway and ER Stress Response with Atherosclerosis Susceptibility

    PubMed Central

    Robinet, Peggy; Smith, Jonathan D.

    2013-01-01

    Cholesterol loaded macrophages in the arterial intima are the earliest histological evidence of atherosclerosis. Studies of mouse models of atherosclerosis have shown that the strain background can have a significant effect on lesion development. We have previously shown that DBA/2 ApoE−/− mice have aortic root lesions 10-fold larger than AKR ApoE−/−mice. The current study analyzes the response to cholesterol loading of macrophages from these two strains. Macrophages from the atherosclerosis susceptible DBA/2 strain had significantly higher levels of total and esterified cholesterol compared to atherosclerosis resistant AKR macrophages, while free cholesterol levels were higher in AKR cells. Gene expression profiles were obtained and data were analyzed for strain, cholesterol loading, and strain-cholesterol loading interaction effects by a fitted linear model. Pathway and transcriptional motif enrichment were identified by gene set enrichment analysis. In addition to observed strain differences in basal gene expression, we identified many transcripts whose expression was significantly altered in response to cholesterol loading, including P2ry13 and P2ry14, Trib3, Hyal1, Vegfa, Ccr5, Ly6a, and Ifit3. Eight pathways were significantly enriched in transcripts regulated by cholesterol loading, among which the lysosome and cytokine-cytokine receptor interaction pathways had the highest number of significantly regulated transcripts. Of the differentially regulated transcripts with a strain-cholesterol loading interaction effect, we identified three genes known to participate in the endoplasmic reticulum (ER) stress response, Ddit3, Trib3 and Atf4. These three transcripts were highly up-regulated by cholesterol in AKR and either down-regulated or unchanged in loaded DBA/2 macrophages, thus associating a robust ER stress response with atherosclerosis resistance. We identified significant transcripts with strain, loading, or strain-loading interaction effect that

  10. Use of cholesterol-loaded cyclodextrin: an alternative for bad cooler stallions.

    PubMed

    Hartwig, F P; Lisboa, F P; Hartwig, F P; Monteiro, G A; Maziero, R R D; Freitas-Dell'Aqua, C P; Alvarenga, M A; Papa, F O; Dell'Aqua, J A

    2014-01-15

    During the cooling process, sperm may suffer irreversible damage that compromises the fertility rate. Incorporating cholesterol-loaded cyclodextrin (CLC) represents a strategy to increase sperm resistance at low temperatures; however, high levels of cholesterol in the cell membrane can interfere with sperm capacitation. The goals of this study were to determine the CLC concentration and cooling temperature that produce optimal kinetic parameters and viability of sperm from stallions identified as bad coolers (BCs) and good coolers (GCs), as well as the effect of adding CLC on the occurrence of the acrosome reaction (ACR) and on the fertility rate of cooled sperm. In experiment 1, each ejaculate was divided into four groups: Control and treated with 1 (CLC-1), 1.5 (CLC-1.5), or 2 mg (CLC-2) of CLC/120 × 10(6) sperm and cooled for 48 hours at 5 °C. In experiment 2, each ejaculate was divided into four groups: Control and CLC-1.5 cooled at 15 °C or 5 °C for 24 hours. For experiment 3, GC and BC stallions were used, and the ejaculates were divided into control and CLC-1.5 cooled at 5 °C for 48 hours. According to experiment, the sperm kinetics (SK) and plasma membrane integrity (PMI) were analyzed before and after 24 and 48 hours of cooling. In experiment 4, the ejaculates were divided into four groups: Control and CLC-1.5 maintained at room temperature or cooled at 5 °C for 24 hours. Each group was incubated with ionophore calcium at 37 °C for 3 hours. The incidence of ACR was analyzed before and after 1, 2, and 3 hours of incubation. For experiment 5, two cycles of 10 mares for a GC stallion and two cycles of 25 for a BC stallion were used. The inseminations were performed with control and CLC-1.5 groups cooled at 5 °C for 24 hours. According to results, all groups treated with CLC exhibited higher PMI compared with controls, and CLC-1.5 and CLC-2 exhibited the best SK results. The cooling temperature of 5 °C was superior to 15 °C when the sperm was treated

  11. Environmental Experience Modulates Ischemia-Induced Amyloidogenesis and Enhances Functional Recovery

    PubMed Central

    Rogozinska, Magdalena; Woods, Julie

    2009-01-01

    Abstract In this study, we examined whether ischemia-induced amyloidogenesis could be modulated by environmental “experience,” and whether this modulation is associated with improved cognitive functioning. Rats were subjected to either global ischemia or sham surgery and then were randomly assigned to either enriched environment housing (EE) or socially paired housing (controls). After 14 days of differential environmental housing, the rats were tested in the water maze. Our results show decreased C-terminal fragments of the β-amyloid precursor protein (βAPP) and decreased amyloid beta (Aβ) load in the ischemic EE rats compared to the ischemic control animals. In addition, Aβ oligomerization was significantly decreased in the ischemic EE animals compared to the ischemic control rats. Further, significantly increased levels of neprilysin, but not insulin-degrading enzyme, amyloid-degrading enzymes, were seen in the ischemic EE rats compared to the ischemic control animals. Behavioral analyses showed that ischemic EE rats performed significantly better on the memory task compared to the ischemic control group. These results suggest that use of multi-sensory environmental enrichment following cerebral ischemia may reduce the accumulation of Aβ peptide in the more pathologic oligomeric form, and consequently may enhance functional recovery. PMID:19271963

  12. Cholesterol-loaded cyclodextrins prevent cryocapacitation damages in buffalo (Bubalus bubalis) cryopreserved sperm.

    PubMed

    Longobardi, Valentina; Albero, Giuseppe; De Canditiis, Carolina; Salzano, Angela; Natale, Antonio; Balestrieri, Anna; Neglia, Gianluca; Campanile, Giuseppe; Gasparrini, Bianca

    2017-02-01

    The aim of this study was to investigate the effect of cholesterol-loaded cyclodextrins (CLC) on motility, viability, capacitation status, and in vivo fertility of buffalo frozen-thawed sperm. After the initial semen assessment, buffalo sperm were diluted in BULLXcell extender containing 0- (control), 1.5-, and 3-mg/mL CLC and cryopreserved. At thawing, sperm motility was evaluated by phase contrast microscopy, and viability-capacitation status was assessed by Hoechst 33258-chlortetracycline (CTC) assay. Capacitation status was also evaluated by an indirect immunofluorescence assay to localize phosphotyrosine-containing proteins. Moreover, buffaloes were artificial inseminated to assess the in vivo-fertilizing potential of CLC-treated semen. No differences among control, 1.5-, and 3-mg/mL CLC-treated groups were recorded in both sperm motility (66.5 ± 5.6, 68.8 ± 4.8, and 68.8 ± 4.8, respectively) and viability (86.5 ± 1.9, 87.6 ± 1.5, 88.4 ± 2.3, respectively). However, the extender supplementation with CLC significantly reduced sperm cryocapacitation. Indeed, CLC treatment decreased (P < 0.01) the proportion of sperm showing the CTC pattern B (capacitated sperm) compared with the control (69.6 ± 3.4, 37.8 ± 1.5, and 51.3 ± 4.7, respectively, with 0, 1.5-, and 3-mg/mL CLC; P < 0.01). Furthermore, the percentage of sperm displaying tyrosine-phosphorylated pattern EA (i.e. high capacitation level) was reduced (P < 0.01) in both CLC-treated groups (10.8 ± 3.3 and 5.6 ± 1.6, respectively, with 1.5- and 3-mg/mL CLC) compared with the control (37.3 ± 6.9), reaching values similar to those recorded in fresh semen (11.0 ± 3.5). In addition, treating sperm with 3-mg/mL CLC increased (P < 0.01) the percentage of nonfluorescent (pattern NF), i.e., non-capacitated sperm (41.8 ± 3.6) compared with fresh semen (11.0 ± 6.9). No differences were recorded in pregnancy rates at 60 days post-artificial insemination among

  13. Lower torso ischemia-induced lung injury is leukocyte dependent.

    PubMed Central

    Klausner, J M; Anner, H; Paterson, I S; Kobzik, L; Valeri, C R; Shepro, D; Hechtman, H B

    1988-01-01

    to these untreated ischemic controls, sheep (n = 7) rendered leukopenic with hydroxyurea or nitrogen mustard and having a total WBC count of 760/mm3 and PMN count of 150/mm3 did not manifest reperfusion-induced increases in MPAP, Pmv, QL, lymph protein clearance, or lung lymph. TxB2 level (p less than 0.05). Plasma TxB2 levels rose slightly at 30 minutes from 199 to 288 pg/ml (p less than 0.05). Lung histology was normal. These data indicate that WBC mediate the ischemia-induced increase in pulmonary microvascular permeability. Images Figs. 5A-C. Figs. 5A-C. Fig. 6. PMID:3196099

  14. Cholesterol loading re-programs the miR-143/145-myocardin axis to convert aortic smooth muscle cells to a dysfunctional macrophage-like phenotype

    PubMed Central

    Vengrenyuk, Yuliya; Nishi, Hitoo; Long, Xiaochun; Ouimet, Mireille; Savji, Nazir; Martinez, Fernando O.; Cassella, Courtney P.; Moore, Kathryn J.; Ramsey, Stephen A.; Miano, Joseph M.; Fisher, Edward A.

    2015-01-01

    Objective We previously showed that cholesterol loading in vitro converts mouse aortic vascular smooth muscle cells (VSMC) from a contractile state to one resembling macrophages. In human and mouse atherosclerotic plaques it has become appreciated that ~40% of cells classified as macrophages by histological markers may be of VSMC origin. We therefore sought to gain insight into the molecular regulation of this clinically relevant process. Approach and Results VSMC of mouse (or human) origin were incubated with cyclodextrin-cholesterol complexes for 72 hours, at which time the expression at the protein and mRNA levels of contractile-related proteins were reduced and of macrophage markers increased. Concurrent was down regulation of miR-143/145, which positively regulate the master VSMC-differentiation transcription factor myocardin (MYOCD). Mechanisms were further probed in mouse VSMC. Maintaining the expression of MYOCD or miR-143/145 prevented and reversed phenotypic changes caused by cholesterol loading. Reversal was also seen when cholesterol efflux was stimulated after loading. Notably, despite expression of macrophage markers, bioinformatic analyses showed that cholesterol-loaded cells remained closer to the VSMC state, consistent with impairment in classical macrophage functions of phagocytosis and efferocytosis. In apoE-deficient atherosclerotic plaques, cells positive for VSMC and macrophage markers were found lining the cholesterol-rich necrotic core. Conclusions Cholesterol loading of VSMC converts them to a macrophage–appearing state by downregulating the miR-143/145-myocardin axis. Though these cells would be classified by immunohistochemistry as macrophages in human and mouse plaques, their transcriptome and functional properties imply that their contributions to atherogenesis would not be those of classical macrophages. PMID:25573853

  15. Simvastatin promotes NPC1-mediated free cholesterol efflux from lysosomes through CYP7A1/LXRα signalling pathway in oxLDL-loaded macrophages.

    PubMed

    Xu, Xiaoyang; Zhang, Aolin; Halquist, Matthew S; Yuan, Xinxu; Henderson, Scott C; Dewey, William L; Li, Pin-Lan; Li, Ningjun; Zhang, Fan

    2017-02-01

    Statins, 3-hydroxyl-3-methylglutaryl coenzyme A reductase inhibitors, are the first-line medications prescribed for the prevention and treatment of coronary artery diseases. The efficacy of statins has been attributed not only to their systemic cholesterol-lowering actions but also to their pleiotropic effects that are unrelated to cholesterol reduction. These pleiotropic effects have been increasingly recognized as essential in statins therapy. This study was designed to investigate the pleiotropic actions of simvastatin, one of the most commonly prescribed statins, on macrophage cholesterol homeostasis with a focus on lysosomal free cholesterol egression. With simultaneous nile red and filipin staining, analysis of confocal/multi-photon imaging demonstrated that simvastatin markedly attenuated unesterified (free) cholesterol buildup in macrophages loaded with oxidized low-density lipoprotein but had little effect in reducing the sizes of cholesteryl ester-containing lipid droplets; the reduction in free cholesterol was mainly attributed to decreases in lysosome-compartmentalized cholesterol. Functionally, the egression of free cholesterol from lysosomes attenuated pro-inflammatory cytokine secretion. It was determined that the reduction of lysosomal free cholesterol buildup by simvastatin was due to the up-regulation of Niemann-Pick C1 (NPC1), a lysosomal residing cholesterol transporter. Moreover, the enhanced enzymatic production of 7-hydroxycholesterol by cytochrome P450 7A1 and the subsequent activation of liver X receptor α underscored the up-regulation of NPC1. These findings reveal a novel pleiotropic effect of simvastatin in affecting lysosomal cholesterol efflux in macrophages and the associated significance in the treatment of atherosclerosis.

  16. Aqueous extract of Cordyceps alleviates cerebral ischemia-induced short-term memory impairment in gerbils

    PubMed Central

    Lee, Sang-Hak; Ko, Il-Gyu; Kim, Sung-Eun; Hwang, Lakkyong; Jin, Jun-Jang; Choi, Hyun-Hee; Kim, Chang-Ju

    2016-01-01

    Cerebral ischemia is caused by reduced cerebral blood flow due to a transient or permanent cerebral artery occlusion. Ischemic injury in the brain leads to neuronal cell death, and eventually causes neurological impairments. Cordyceps, the name given to the fungi on insects, has abundant useful natural products with various biological activities. Cordyceps is known to have nephroprotective, hepatoprotective, anti-inflammatory, antioxidative, and antiapoptotic effects. We investigated the effects of Cordyceps on short-term memory, neuronal apoptosis, and cell proliferation in the hippocampal dentate gyrus following transient global ischemia in gerbils. For this study, a step-down avoidance test, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, immunohistochemistry for caspase-3 and 5-bromo-2′-de-oxyuridine, and western blot for Bax, Bcl-2, brain-derived neurotrophic factor (BDNF), and tyrosin kinase B were performed. In the present study, Cordyceps alleviated cerebral ischemia-induced short-term memory impairment. Cordyceps showed therapeutic effects through inhibiting cerebral ischemia-induced apoptosis in the hippocampus. Cordyceps suppressed cerebral ischemia-induced cell proliferation in the hippocampal dentate gyrus due to the reduced apoptotic neuronal cell death. Cordyceps treatment also enhanced BDNF and TrkB expressions in the hippocampus of ischemic gerbils. It can be suggested that Cordyceps overcomes cerebral ischemia-induced neuronal apoptosis, thus facilitates recovery following cerebral ischemia injury. PMID:27162767

  17. Aqueous extract of Cordyceps alleviates cerebral ischemia-induced short-term memory impairment in gerbils.

    PubMed

    Lee, Sang-Hak; Ko, Il-Gyu; Kim, Sung-Eun; Hwang, Lakkyong; Jin, Jun-Jang; Choi, Hyun-Hee; Kim, Chang-Ju

    2016-04-01

    Cerebral ischemia is caused by reduced cerebral blood flow due to a transient or permanent cerebral artery occlusion. Ischemic injury in the brain leads to neuronal cell death, and eventually causes neurological impairments. Cordyceps, the name given to the fungi on insects, has abundant useful natural products with various biological activities. Cordyceps is known to have nephroprotective, hepatoprotective, anti-inflammatory, antioxidative, and antiapoptotic effects. We investigated the effects of Cordyceps on short-term memory, neuronal apoptosis, and cell proliferation in the hippocampal dentate gyrus following transient global ischemia in gerbils. For this study, a step-down avoidance test, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, immunohistochemistry for caspase-3 and 5-bromo-2'-de-oxyuridine, and western blot for Bax, Bcl-2, brain-derived neurotrophic factor (BDNF), and tyrosin kinase B were performed. In the present study, Cordyceps alleviated cerebral ischemia-induced short-term memory impairment. Cordyceps showed therapeutic effects through inhibiting cerebral ischemia-induced apoptosis in the hippocampus. Cordyceps suppressed cerebral ischemia-induced cell proliferation in the hippocampal dentate gyrus due to the reduced apoptotic neuronal cell death. Cordyceps treatment also enhanced BDNF and TrkB expressions in the hippocampus of ischemic gerbils. It can be suggested that Cordyceps overcomes cerebral ischemia-induced neuronal apoptosis, thus facilitates recovery following cerebral ischemia injury.

  18. Blockade of calcium-permeable AMPA receptors protects hippocampal neurons against global ischemia-induced death

    PubMed Central

    Noh, Kyung-Min; Yokota, Hidenori; Mashiko, Toshihiro; Castillo, Pablo E.; Zukin, R. Suzanne; Bennett, Michael V. L.

    2005-01-01

    Transient global or forebrain ischemia induced experimentally in animals can cause selective, delayed neuronal death of hippocampal CA1 pyramidal neurons. A striking feature is a delayed rise in intracellular free Zn2+ in CA1 neurons just before the onset of histologically detectable cell death. Here we show that α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors (AMPARs) at Schaffer collateral to CA1 synapses in postischemic hippocampus exhibit properties of Ca2+/Zn2+-permeable, Glu receptor 2 (GluR2)-lacking AMPARs before the rise in Zn2+ and cell death. At 42 h after ischemia, AMPA excitatory postsynaptic currents exhibited pronounced inward rectification and marked sensitivity to 1-naphthyl acetyl spermine (Naspm), a selective channel blocker of GluR2-lacking AMPARs. In control hippocampus, AMPA excitatory postsynaptic currents were electrically linear and relatively insensitive to Naspm. Naspm injected intrahippocampally at 9-40 h after insult greatly reduced the late rise in intracellular free Zn2+ in postischemic CA1 neurons and afforded partial protection against ischemia-induced cell death. These results implicate GluR2-lacking AMPA receptors in the ischemia-induced rise in free Zn2+ and death of CA1 neurons, although a direct action at the time of the rise in Zn2+ is unproven. This receptor subtype appears to be an important therapeutic target for intervention in ischemia-induced neuronal death in humans. PMID:16093311

  19. Early immature neuronal death initiates cerebral ischemia-induced neurogenesis in the dentate gyrus.

    PubMed

    Kim, D H; Lee, H E; Kwon, K J; Park, S J; Heo, H; Lee, Y; Choi, J W; Shin, C Y; Ryu, J H

    2015-01-22

    Throughout adulthood, neurons are continuously replaced by new cells in the dentate gyrus (DG) of the hippocampus, and this neurogenesis is increased by various neuronal injuries including ischemic stroke and seizure. While several mechanisms of this injury-induced neurogenesis have been elucidated, the initiation factor remains unclear. Here, we investigated which signal(s) trigger(s) ischemia-induced cell proliferation and neurogenesis in the hippocampal DG region. We found that early apoptotic cell death of the immature neurons occurred in the DG region following transient forebrain ischemia/reperfusion in mice. Moreover, early immature neuronal death in the DG initiated transient forebrain ischemia/reperfusion-induced neurogenesis through glycogen synthase kinase-3β/β-catenin signaling, which was mediated by microglia-derived insulin-like growth factor-1 (IGF-1). Additionally, we observed that the blockade of immature neuronal cell death, early microglial activation, or IGF-1 signaling attenuated ischemia-induced neurogenesis. These results suggest that early immature neuronal cell death initiates ischemia-induced neurogenesis through microglial IGF-1 in mice.

  20. Pretreatment of Asian elephant (Elephas maximus) spermatozoa with cholesterol-loaded cyclodextrins and glycerol addition at 4°C improves cryosurvival.

    PubMed

    Kiso, Wendy K; Asano, Atsushi; Travis, Alexander J; Schmitt, Dennis L; Brown, Janine L; Pukazhenthi, Budhan S

    2012-01-01

    Asian elephant spermatozoa are sensitive to chilling and do not respond well to cryopreservation. The objectives of the present study were to: (1) determine whether cholesterol content can be modified by preincubation of Asian elephant spermatozoa with cholesterol-loaded cyclodextrin (CLC); and (2) assess the effects of CLC concentration(s), temperature at time of glycerol addition (22°C vs 4°C) and dilution medium on post-thaw sperm survival. Spermatozoa incubated with ≥1.5 mg CLC exhibited increased (P < 0.05) cholesterol concentrations. Pretreatment of spermatozoa with 1.5 mg CLC resulted in improvements (P < 0.05) in all post-thaw parameters. Glycerol addition at 4°C also improved all post-thaw parameters compared with 22°C. Dilution of thawed spermatozoa in an egg yolk-based medium improved (P < 0.05) motility compared with Ham's F-10 culture medium. In summary, our findings indicate that modifying cholesterol content within the plasma membrane improves the cryosurvival of Asian elephant spermatozoa. The development of an improved cryopreservation method that includes modification of membrane cholesterol and the addition of glycerol at 4°C, as reported in the present study, is an important step towards utilisation of cryopreserved spermatozoa in captive management of this species.

  1. Use of cholesterol-loaded cyclodextrin in donkey semen cryopreservation improves sperm viability but results in low fertility in mares.

    PubMed

    Oliveira, R R; Rates, D M; Pugliesi, G; Ker, P G; Arruda, R P; Moraes, E A; Carvalho, G R

    2014-10-01

    The use of cholesterol-loaded cyclodextrin (CLC) on semen cryopreservation has been related with better sperm viability in several species; however, the effect on fertility is not known in donkey semen. Ejaculates (n = 25) from five donkeys were diluted in S-MEDIUM with 0, 1, 2 or 3 mg of CLC/120 × 10(6) spermatozoa. Semen was frozen, and thawed samples were evaluated by computer-assisted sperm analyser system (CASA), supravital test, hyposmotic swelling test and fluorescent dyes to assess the integrity of sperm membranes. Mares (n = 60) were inseminated with frozen-thawed semen treated with the doses of 0 or 1 mg CLC. Percentages of sperm with progressive motility and with functional plasma membrane were greater (p < 0.05) in the CLC-treated groups than in the control. Percentages of intact plasma membrane and intact plasma membrane and acrosome detected by fluorescent dyes were also greater (p < 0.05) in CLC-treated groups. Although no difference (p > 0.05) in conception rates was detected between groups (control, 3/30, 10%; CLC-treated, 1/30, 3.3%), fertility was low for artificial insemination programs in mares. Therefore, we firstly demonstrated that frozen semen treated with CLC in S-MEDIA extender before freezing improves the in vitro sperm viability, but semen treated or not with CLC in S-MEDIUM extender results in a very low conception rate in mares inseminated with thawed donkey semen.

  2. Protective effect of cholesterol-loaded cyclodextrin pretreatment against hydrogen peroxide induced oxidative damage in ram sperm.

    PubMed

    Naseer, Zahid; Ahmad, Ejaz; Aksoy, Melih; Küçük, Niyazi; Serin, İlker; Ceylan, Ahmet; Boyacıoğlu, Murat; Kum, Cavit

    2015-08-01

    Three experiments were conducted to determine the protective effect of cholesterol-loaded cyclodextrin (CLC) against hydrogen peroxide (H2O2) or cryo-induced damage in ram sperm. In Experiment 1, the fresh ejaculates were either treated with CLC or remained untreated. Both CLC treated and untreated samples were then incubated with 0, 250 or 500 μM H2O2 at 35°C for 12 h. After incubation period of 12 h, the motility, viability and membrane integrity remained higher in CLC treated sperm even in the presence of 250 or 500 μM H2O2. The H2O2 treatment affected all the sperm parameters adversely (P<0.05). However, compared to CLC untreated counterpart, the motility, viability and membrane integrity remained higher (P<0.05) in treated sperm, even in the presence of 250 or 500 μM H2O2 during 12 h of incubation. In Experiment 2, semen was cryopreserved in the presence or absence of CLC. The post-thaw results revealed that CLC treated sperm has higher (P<0.05) motility, viability and membrane integrity compared to the control. In Experiment 3, lipid peroxidation levels were assessed by determining malondialdehyde (MDA) concentrations during the H2O2-induced oxidative stress in CLC treated and untreated sperm. However, no difference (P>0.05) in MDA level was observed among the groups at any stage of incubation. In conclusion, the CLC incorporation in ram sperm membrane may protects it against H2O2 or cryo-induced oxidative damage. The cryoprotective influence of CLC on ram sperm might be resulted from, at least partly, its antioxidative property.

  3. Egg Yolk and Glycerol Requirements for Freezing Boar Spermatozoa Treated with Methyl β-Cyclodextrin or Cholesterol-loaded Cyclodextrin

    PubMed Central

    BLANCH, Eva; TOMÁS, Cristina; HERNÁNDEZ, Marta; ROCA, Jordi; MARTÍNEZ, Emilio A.; VÁZQUEZ, Juan M.; MOCÉ, Eva

    2014-01-01

    Egg yolk (EY) and glycerol are common constituents of extenders used for sperm cryopreservation. It has been demonstrated that using cholesterol-loaded cyclodextrins (CLC) improves sperm cryosurvival in several species. However, standard freezing extenders might not be the most appropriate for CLC-treated sperm. This study evaluated the EY and glycerol requirements for freezing CLC-treated boar spermatozoa. Semen samples from 34 ejaculates coming from 4 boars were used. Each ejaculate was split into three aliquots: one was used untreated (control), and the other two were treated with 1 mg of CLC or methyl-β-cyclodextrin/120 × 106 sperm for 15 min at 22 C prior to cryopreservation. Our results indicated that reducing the concentration of EY was detrimental for sperm viability after thawing (31.57 ± 2 vs. 19.89% ± 2 for 20 and 10% EY, respectively; P <0.05), even in semen treated with CLC. On the other hand, it was observed that the traditional concentration of glycerol (3%) was not the appropriate for freezing CLC-treated sperm (61.10 ± 3 vs. 47.87% ± 3 viable sperm for control and CLC-treated sperm, respectively; P <0.05). Thus, CLC-treated sperm showed a higher tolerance to high glycerol concentrations (5%) in terms of sperm viability (59.19% ± 3) than non-treated sperm (45.58% ± 3; P<0.05). Therefore, it could be necessary to modify the freezing extenders for CLC-treated sperm. Nevertheless, additional studies will be needed to evaluate alternative cryoprotectants and to determine the effect of high glycerol concentrations on sperm functionality. PMID:24492655

  4. Exercise training attenuates placental ischemia induced hypertension and angiogenic imbalance in the rat

    PubMed Central

    Gilbert, Jeffrey S; Banek, Christopher T; Bauer, Ashley J; Gingery, Anne; Needham, Karen

    2013-01-01

    An imbalance between pro-angiogenic (vascular endothelial growth factor, VEGF) and anti-angiogenic (soluble fms-like tyrosine kinase-1, sFlt-1) factors plays an important role in hypertension associated with reduced utero-placental perfusion (RUPP). Exercise has been shown to stimulate pro-angiogenic factors such as VEGF in both the pregnant and non-pregnant state, thus we hypothesized exercise training would attenuate both angiogenic imbalance and hypertension due to RUPP. Four groups of animals were studied: RUPP and normal pregnant (NP) controls and NP and RUPP + exercise training (NP or RUPP+EX). Exercise training attenuated RUPP-induced: hypertension (P<0.05); increased sFlt-1(P<0.05); decreased VEGF (P<0.05), and elevated sFlt-1:VEGF ratio. The positive effects of exercise on angiogenic balance in the RUPP rats were confirmed by restoration (P<0.05) of the RUPP-induced decrease in endothelial tube formation in HUVECs treated with serum from each of the experimental groups. Placental prolyl hydroxylase-1 (PHD1) was increased (P<0.05) in RUPP+Ex rats. Decreased trolox equivalent antioxidant capacity in the placenta, amniotic fluid and kidney of the RUPP rats was reversed by exercise. RUPP induced increase in renal TBARS was attenuated by exercise. The present data show exercise training before and during pregnancy attenuates placental ischemia-induced hypertension, angiogenic imbalance and oxidative stress in the RUPP rat and reveals that increased PHD1 is associated with decreased sFlt-1 thus revealing several potential pathways for exercise training to mitigate the effects of placental ischemia-induced hypertension. Lastly, the present study demonstrates exercise training may be a useful approach to attenuate the development of placental ischemia-induced hypertension during pregnancy. PMID:23090773

  5. Exercise training attenuates placental ischemia-induced hypertension and angiogenic imbalance in the rat.

    PubMed

    Gilbert, Jeffrey S; Banek, Christopher T; Bauer, Ashley J; Gingery, Anne; Needham, Karen

    2012-12-01

    An imbalance between proangiogenic (vascular endothelial growth factor) and antiangiogenic (soluble fms-like tyrosine kinase 1) factors plays an important role in hypertension associated with reduced uteroplacental perfusion (RUPP). Exercise has been shown to stimulate proangiogenic factors, such as vascular endothelial growth factor, in both the pregnant and nonpregnant state; thus, we hypothesized that exercise training would attenuate both angiogenic imbalance and hypertension attributed to RUPP. Four groups of animals were studied, RUPP and normal pregnant controls and normal pregnant and RUPP+exercise training. Exercise training attenuated RUPP-induced hypertension (P<0.05), decreased soluble fms-like tyrosine kinase 1 (P<0.05), increased VEGF (P<0.05), and elevated the soluble fms-like tyrosine kinase 1:vascular endothelial growth factor ratio. The positive effects of exercise on angiogenic balance in the RUPP rats were confirmed by restoration (P<0.05) of the RUPP-induced decrease in endothelial tube formation in human umbilical vascular endothelial cells treated with serum from each of the experimental groups. Placental prolyl hydroxylase 1 was increased (P<0.05) in RUPP+exercise training rats. Decreased trolox equivalent antioxidant capacity in the placenta, amniotic fluid, and kidney of the RUPP rats was reversed by exercise. RUPP-induced increase in renal thiobarbituric acid reactive species was attenuated by exercise. The present data show that exercise training before and during pregnancy attenuates placental ischemia-induced hypertension, angiogenic imbalance, and oxidative stress in the RUPP rat and reveals that increased prolyl hydroxylase 1 is associated with decreased soluble fms-like tyrosine kinase 1, thus revealing several potential pathways for exercise training to mitigate the effects of placental ischemia-induced hypertension. Lastly, the present study demonstrates that exercise training may be a useful approach to attenuate the development

  6. Blockade of advanced glycation end-product formation restores ischemia-induced angiogenesis in diabetic mice

    PubMed Central

    Tamarat, Radia; Silvestre, Jean-Sébastien; Huijberts, Maya; Benessiano, Joelle; Ebrahimian, Teni G.; Duriez, Micheline; Wautier, Marie-Paule; Wautier, Jean Luc; Lévy, Bernard I.

    2003-01-01

    We hypothesized that formation of advanced glycation end products (AGEs) associated with diabetes reduces matrix degradation by metalloproteinases (MMPs) and contributes to the impairment of ischemia-induced angiogenesis. Mice were treated or not with streptozotocin (40 mg/kg) and streptozotocin plus aminoguanidine (AGEs formation blocker, 50 mg/kg). After 8 weeks of treatment, hindlimb ischemia was induced by right femoral artery ligature. Plasma AGE levels were strongly elevated in diabetic mice when compared with control mice (579 ± 21 versus 47 ± 4 pmol/ml, respectively; P < 0.01). Treatment with aminoguanidine reduced AGE plasma levels when compared with untreated diabetic mice (P < 0.001). After 28 days of ischemia, ischemic/nonischemic leg angiographic score, capillary density, and laser Doppler skin-perfusion ratios were 1.4-, 1.5-, and 1.4-fold decreased in diabetic mice in reference to controls (P < 0.01). Treatment with aminoguanidine completely normalized ischemia-induced angiogenesis in diabetic mice. We next analyzed the role of proteolysis in AGE formation-induced hampered neovascularization process. After 3 days of ischemia, MMP-2 activity and MMP-3 and MMP-13 protein levels were increased in untreated and aminoguanidine-treated diabetic mice when compared with controls (P < 0.05). Despite this activation of the MMP pathway, collagenolysis was decreased in untreated diabetic mice. Conversely, treatment of diabetic mice with aminoguanidine restored collagenolysis toward levels found in control mice. In conclusion, blockade of AGE formation by aminoguanidine normalizes impaired ischemia-induced angiogenesis in diabetic mice. This effect is probably mediated by restoration of matrix degradation processes that are disturbed as a result of AGE accumulation. PMID:12805564

  7. Blockade of advanced glycation end-product formation restores ischemia-induced angiogenesis in diabetic mice.

    PubMed

    Tamarat, Radia; Silvestre, Jean-Sébastien; Huijberts, Maya; Benessiano, Joelle; Ebrahimian, Teni G; Duriez, Micheline; Wautier, Marie-Paule; Wautier, Jean Luc; Lévy, Bernard I

    2003-07-08

    We hypothesized that formation of advanced glycation end products (AGEs) associated with diabetes reduces matrix degradation by metalloproteinases (MMPs) and contributes to the impairment of ischemia-induced angiogenesis. Mice were treated or not with streptozotocin (40 mg/kg) and streptozotocin plus aminoguanidine (AGEs formation blocker, 50 mg/kg). After 8 weeks of treatment, hindlimb ischemia was induced by right femoral artery ligature. Plasma AGE levels were strongly elevated in diabetic mice when compared with control mice (579 +/- 21 versus 47 +/- 4 pmol/ml, respectively; P < 0.01). Treatment with aminoguanidine reduced AGE plasma levels when compared with untreated diabetic mice (P < 0.001). After 28 days of ischemia, ischemic/nonischemic leg angiographic score, capillary density, and laser Doppler skin-perfusion ratios were 1.4-, 1.5-, and 1.4-fold decreased in diabetic mice in reference to controls (P < 0.01). Treatment with aminoguanidine completely normalized ischemia-induced angiogenesis in diabetic mice. We next analyzed the role of proteolysis in AGE formation-induced hampered neovascularization process. After 3 days of ischemia, MMP-2 activity and MMP-3 and MMP-13 protein levels were increased in untreated and aminoguanidine-treated diabetic mice when compared with controls (P < 0.05). Despite this activation of the MMP pathway, collagenolysis was decreased in untreated diabetic mice. Conversely, treatment of diabetic mice with aminoguanidine restored collagenolysis toward levels found in control mice. In conclusion, blockade of AGE formation by aminoguanidine normalizes impaired ischemia-induced angiogenesis in diabetic mice. This effect is probably mediated by restoration of matrix degradation processes that are disturbed as a result of AGE accumulation.

  8. About Cholesterol

    MedlinePlus

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More About Cholesterol Updated:Jul 5,2017 Whether you’ve just ... Quiz This content was last reviewed April 2017. Cholesterol • Home • About Cholesterol Introduction Atherosclerosis What Your Cholesterol ...

  9. What's Cholesterol?

    MedlinePlus

    ... Room? What Happens in the Operating Room? What's Cholesterol? KidsHealth > For Kids > What's Cholesterol? A A A ... thing for food to be low in it? Cholesterol and Your Body Cholesterol (say: kuh-LES-tuh- ...

  10. O-GlcNAcylation regulates ischemia-induced neuronal apoptosis through AKT signaling

    PubMed Central

    Shi, Jianhua; Gu, Jin-hua; Dai, Chun-ling; Gu, Jianlan; Jin, Xiaoxia; Sun, Jianming; Iqbal, Khalid; Liu, Fei; Gong, Cheng-Xin

    2015-01-01

    Apoptosis plays an important role in neural development and neurological disorders. In this study, we found that O-GlcNAcylation, a unique protein posttranslational modification with O-linked β-N-acetylglucosamine (GlcNAc), promoted apoptosis through attenuating phosphorylation/activation of AKT and Bad. By using co-immunoprecipitation and mutagenesis techniques, we identified O-GlcNAc modification at both Thr308 and Ser473 of AKT. O-GlcNAcylation-induced apoptosis was attenuated by over-expression of AKT. We also found a dynamic elevation of protein O-GlcNAcylation during the first four hours of cerebral ischemia, followed by continuous decline after middle cerebral artery occlusion (MCAO) in the mouse brain. The elevation of O-GlcNAcylation coincided with activation of cell apoptosis. Finally, we found a negative correlation between AKT phosphorylation and O-GlcNAcylation in ischemic brain tissue. These results indicate that cerebral ischemia induces a rapid increase of O-GlcNAcylation that promotes apoptosis through down-regulation of AKT activity. These findings provide a novel mechanism through which O-GlcNAcylation regulates ischemia-induced neuronal apoptosis through AKT signaling. PMID:26412745

  11. CNT loading into cationic cholesterol suspensions show improved DNA binding and serum stability and ability to internalize into cancer cells

    NASA Astrophysics Data System (ADS)

    Chhikara, Bhupender S.; Misra, Santosh K.; Bhattacharya, Santanu

    2012-02-01

    Methods which disperse single-walled carbon nanotubes (SWNTs) in water as ‘debundled’, while maintaining their unique physical properties are highly useful. We present here a family of cationic cholesterol compounds (Chol+) {Cholest-5en-3β-oxyethyl pyridinium bromide (Chol-PB+), Cholest-5en-3β-oxyethyl N-methyl pyrrolidinium bromide (Chol-MPB+), Cholest-5en-3β-oxyethyl N-methyl morpholinium bromide (Chol-MMB+) and Cholest-5en-3β-oxyethyl diazabicyclo octanium bromide (Chol-DOB+)}. Each of these could be easily dispersed in water. The resulting cationic cholesterol (Chol+) suspensions solubilized single-walled carbon nanotubes (SWCNTs) by the non-specific physical adsorption of Chol+ to form stable, transparent, dark aqueous suspensions at room temperature. Electron microscopy reveals the existence of highly segregated CNTs in these samples. Zeta potential measurements showed an increase in potential of cationic cholesterol aggregates on addition of CNTs. The CNT-Chol+ suspensions were capable of forming stable complexes with genes (DNA) efficiently. The release of double-helical DNA from such CNT-Chol+ complexes could be induced upon the addition of anionic micellar solution of SDS. Furthermore, the CNT-based DNA complexes containing cationic cholesterol aggregates showed higher stability in fetal bovine serum media at physiological conditions. Confocal studies confirm that CNT-Chol+ formulations adhere to HeLa cell surfaces and get internalized more efficiently than the cationic cholesterol suspensions alone (devoid of any CNTs). These cationic cholesterol-CNT suspensions therefore appear to be a promising system for further use in biological applications.

  12. Alpinetin enhances cholesterol efflux and inhibits lipid accumulation in oxidized low-density lipoprotein-loaded human macrophages.

    PubMed

    Jiang, Zhengming; Sang, Haiqiang; Fu, Xin; Liang, Ying; Li, Ling

    2015-01-01

    Alpinetin is a natural flavonoid abundantly present in the ginger family. Here, we investigated the effect of alpinetin on cholesterol efflux and lipid accumulation in oxidized low-density lipoprotein (ox-LDL)-treated THP-1 macrophages and human peripheral blood monocyte-derived macrophages (HMDMs). After exposing THP-1 macrophages to alpinetin, cholesterol efflux was determined by liquid scintillator. The mRNA and protein levels of peroxisome proliferator-activated receptor gamma (PPAR-γ), liver X receptor alpha (LXR-α), ATP-binding cassette transporter A1 (ABCA1), and ABCG1 and scavenger receptor class B member 1 were determined by reverse-transcriptase PCR (RT-PCR) and Western blot analysis, respectively. Alpinetin promoted apolipoprotein A-I- and high-density-lipoprotein-mediated cholesterol efflux and elevated PPAR-γ and LXR-α mRNA and protein expression in a dose-dependent fashion in ox-LDL-treated THP-1 macrophages and HMDMs. Small interfering RNA-mediated silencing of PPAR-γ or LXR-α dose dependently reversed alpinetin-increased cholesterol efflux in THP-1 macrophages, indicating the involvement of PPAR-γ and LXR-α in alpinetin-promoted cholesterol efflux. Alpinetin inhibited ox-LDL-induced lipid accumulation and enhanced the expression of ABCA1 and ABCG1 mRNA and protein, which was reversed by specific knockdown of PPAR-γ or LXR-α. Taken together, our results reveal that alpinetin exhibits positive effects on cholesterol efflux and inhibits ox-LDL-induced lipid accumulation, which might be through PPAR-γ/LXR-α/ABCA1/ABCG1 pathway.

  13. Ischemia-induced neural stem/progenitor cells in the pia mater following cortical infarction.

    PubMed

    Nakagomi, Takayuki; Molnár, Zoltán; Nakano-Doi, Akiko; Taguchi, Akihiko; Saino, Orie; Kubo, Shuji; Clausen, Martijn; Yoshikawa, Hiroo; Nakagomi, Nami; Matsuyama, Tomohiro

    2011-12-01

    Increasing evidence shows that neural stem/progenitor cells (NSPCs) can be activated in the nonconventional neurogenic zones such as the cortex following ischemic stroke. However, the precise origin, identity, and subtypes of the ischemia-induced NSPCs (iNSPCs), which can contribute to cortical neurogenesis, is currently still unclear. In our present study, using an adult mouse cortical infarction model, we found that the leptomeninges (pia mater), which is widely distributed within and closely associated with blood vessels as microvascular pericytes/perivascular cells throughout central nervous system (CNS), have NSPC activity in response to ischemia and can generate neurons. These observations indicate that microvascular pericytes residing near blood vessels that are distributed from the leptomeninges to the cortex are potential sources of iNSPCs for neurogenesis following cortical infarction. In addition, our results propose a novel concept that the leptomeninges, which cover the entire brain, have an important role in CNS restoration following brain injury such as stroke.

  14. Moderate or deep local hypothermia does not prevent the onset of ischemia-induced dendritic damage

    PubMed Central

    Tran, Sherri; Chen, Shangbin; Liu, Ran R; Xie, Yicheng; Murphy, Timothy H

    2012-01-01

    We studied the acute (up to 2 hours after reperfusion) effects of localized cortical hypothermia on ischemia-induced dendritic structural damage. Moderate (31°C) and deep (22°C) hypothermia delays, but does not block the onset of dendritic blebbing or spine loss during global ischemia in mouse in vivo. Hypothermic treatment promoted more consistent recovery of dendritic structure and spines during reperfusion. These results suggest that those using therapeutic hypothermia will need to consider that it does not spare neurons from structural changes that are the result of ischemia, but hypothermia may interact with mechanisms that control the onset of damage and recovery during reperfusion. PMID:22167237

  15. Complement activation is critical for placental ischemia-induced hypertension in the rat.

    PubMed

    Lillegard, Kathryn E; Johnson, Alex C; Lojovich, Sarah J; Bauer, Ashley J; Marsh, Henry C; Gilbert, Jeffrey S; Regal, Jean F

    2013-11-01

    Preeclampsia is a major obstetric problem defined by new-onset hypertension and proteinuria associated with compromised placental perfusion. Although activation of the complement system is increased in preeclampsia compared to normal pregnancy, it remains unclear whether excess complement activation is a cause or consequence of placental ischemia. Therefore, we hypothesized that complement activation is critical for placental ischemia-induced hypertension. We employed the reduced utero-placental perfusion pressure (RUPP) model of placental ischemia in the rat to induce hypertension in the third trimester and evaluated the effect of inhibiting complement activation with a soluble recombinant form of an endogenous complement regulator, human complement receptor 1 (sCR1; CDX-1135). On day 14 of a 21-day gestation, rats received either RUPP or Sham surgery and 15 mg/kg/day sCR1 or saline intravenously on days 14-18. Circulating complement component 3 decreased and complement activation product C3a increased in RUPP vs. Sham (p<0.05), indicating complement activation had occurred. Mean arterial pressure (MAP) measured on day 19 increased in RUPP vs. Sham rats (109.8±2.8 mmHg vs. 93.6±1.6 mmHg). Treatment with sCR1 significantly reduced elevated MAP in RUPP rats (98.4±3.6 mmHg, p<0.05) and reduced C3a production. Vascular endothelial growth factor (VEGF) decreased in RUPP compared to Sham rats, and the decrease in VEGF was not affected by sCR1 treatment. Thus, these studies have identified a mechanistic link between complement activation and the pregnancy complication of hypertension apart from free plasma VEGF and have identified complement inhibition as a potential treatment strategy for placental ischemia-induced hypertension in preeclampsia.

  16. LOX-1 plays an important role in ischemia-induced angiogenesis of limbs.

    PubMed

    Shiraki, Takeru; Aoyama, Takuma; Yokoyama, Chiharu; Hayakawa, Yuka; Tanaka, Toshiki; Nishigaki, Kazuhiko; Sawamura, Tatsuya; Minatoguchi, Shinya

    2014-01-01

    LOX-1, lectin-like oxidized low-density lipoprotein (LDL) receptor-1, is a single transmembrane receptor mainly expressed on endothelial cells. LOX-1 mediates the uptake of oxidized LDL, an early step in atherosclerosis; however, little is known about whether LOX-1 is involved in angiogenesis during tissue ischemia. Therefore, we examined the role of LOX-1 in ischemia-induced angiogenesis in the hindlimbs of LOX-1 knockout (KO) mice. Angiogenesis was evaluated in a surgically induced hindlimb ischemia model using laser Doppler blood flowmetry (LDBF) and histological capillary density (CD) and arteriole density (AD). After right hindlimb ischemia, the ischemic/nonischemic hindlimb blood flow ratio was persistently lower in LOX-1 KO mice than in wild-type (WT) mice. CD and AD were significantly smaller in LOX-1 KO mice than in WT mice on postoperative day 14. Immunohistochemical analysis revealed that the number of macrophages infiltrating ischemic tissues was significantly smaller in LOX-1 KO mice than in WT mice. The number of infiltrated macrophages expressing VEGF was also significantly smaller in LOX-1 KO mice than in WT mice. Western blot analysis and ROS production assay revealed that LOX- KO mice show significant decrease in Nox2 expression, ROS production and HIF-1α expression, the phosphorylation of p38 MAPK and NF-κB p65 subunit as well as expression of redox-sensitive vascular cell adhesion molecule-1 (VCAM-1) and LOX-1 itself in ischemic muscles, which is supposed to be required for macrophage infiltration expressing angiogenic factor VEGF. Reduction of VEGF expression successively suppressed the phosphorylation of Akt and eNOS, which accelerated angiogenesis, in the ischemic leg of LOX-1 KO mice. Our findings indicate that LOX-1 plays an important role in ischemia-induced angiogenesis by 1) Nox2-ROS-NF-κB activation, 2) upregulated expression of adhesion molecules: VCAM-1 and LOX-1 and 3) promoting macrophage infiltration, which expresses angiogenic

  17. Neutrophil Depletion Attenuates Placental Ischemia-Induced Hypertension in the Rat

    PubMed Central

    Regal, Jean F.; Lillegard, Kathryn E.; Bauer, Ashley J.; Elmquist, Barbara J.; Loeks-Johnson, Alex C.; Gilbert, Jeffrey S.

    2015-01-01

    Preeclampsia is characterized by reduced placental perfusion with placental ischemia and hypertension during pregnancy. Preeclamptic women also exhibit a heightened inflammatory state and greater number of neutrophils in the vasculature compared to normal pregnancy. Since neutrophils are associated with tissue injury and inflammation, we hypothesized that neutrophils are critical to placental ischemia-induced hypertension and fetal demise. Using the reduced uteroplacental perfusion pressure (RUPP) model of placental ischemia-induced hypertension in the rat, we determined the effect of neutrophil depletion on blood pressure and fetal resorptions. Neutrophils were depleted with repeated injections of polyclonal rabbit anti-rat polymorphonuclear leukocyte (PMN) antibody (antiPMN). Rats received either antiPMN or normal rabbit serum (Control) on 13.5, 15.5, 17.5, and 18.5 days post conception (dpc). On 14.5 dpc, rats underwent either Sham surgery or clip placement on ovarian arteries and abdominal aorta to reduce uterine perfusion pressure (RUPP). On 18.5 dpc, carotid arterial catheters were placed and mean arterial pressure (MAP) was measured on 19.5 dpc. Neutrophil-depleted rats had reduced circulating neutrophils from 14.5 to 19.5 dpc compared to Control, as well as decreased neutrophils in lung and placenta on 19.5 dpc. MAP increased in RUPP Control vs Sham Control rats, and neutrophil depletion attenuated this increase in MAP in RUPP rats without any effect on Sham rats. The RUPP-induced increase in fetal resorptions and complement activation product C3a were not affected by neutrophil depletion. Thus, these data are the first to indicate that neutrophils play an important role in RUPP hypertension and that cells of the innate immune system may significantly contribute to pregnancy-induced hypertension. PMID:26135305

  18. Characterization of Cardiac Anoctamin1 Ca2+-Activated Chloride Channels and Functional Role in Ischemia-Induced Arrhythmias

    PubMed Central

    Ye, Zhen; Wu, Ming-Ming; Wang, Chun-Yu; Li, Yan-Chao; Yu, Chang-Jiang; Gong, Yuan-Feng; Zhang, Jun; Wang, Qiu-Shi; Song, Bin-Lin; Yu, Kuai; Hartzell, H. Criss; Duan, Dayue Darrel; Zhao, Dan; Zhang, Zhi-Ren

    2015-01-01

    Anoctamin1 (ANO1) encodes a Ca2+-activated chloride (Cl−) channel (CaCC) in variety tissues of many species. Whether ANO1 expresses and functions as a CaCC in cardiomyocytes remain unknown. The objective of this study is to characterize the molecular and functional expression of ANO1 in cardiac myocytes and the role of ANO1-encoded CaCCs in ischemia-induced arrhythmias in the heart. Quantitative real-time RT-PCR, immunofluorescence staining assays, and immunohistochemistry identified the molecular expression, location, and distribution of ANO1 in mouse ventricular myocytes (mVMs). Patch-clamp recordings combined with pharmacological analyses found that ANO1 was responsible for a Ca2+-activated Cl− current (ICl.Ca) in cardiomyocytes. Myocardial ischemia led to a significant increase in the current density of ICl.Ca, which was inhibited by a specific ANO1 inhibitor, T16Ainh-A01, and an antibody targeting at the pore area of ANO1. Moreover, cardiomyocytes isolated from mice with ischemia-induced arrhythmias had an accelerated early phase 1 repolarization of action potentials (APs) and a deeper “spike and dome” compared to control cardiomyocytes from non-ischemia mice. Application of the antibody targeting at ANO1 pore prevented the ischemia-induced early phase 1 repolarization acceleration and caused a much shallower “spike and dome”. We conclude that ANO1 encodes CaCC and plays a significant role in the phase 1 repolarization of APs in mVMs. The ischemia-induced increase in ANO1 expression may be responsible for the increased density of ICl.Ca in the ischemic heart and may contribute, at least in part, to ischemia-induced arrhythmias. PMID:24962810

  19. The effect of cholesterol loaded cyclodextrins on post-thawing quality of buffalo semen in relation to sperm DNA damage and ultrastructure.

    PubMed

    Ezz, Mohamed Aboul; Montasser, Abd Elmonem; Hussein, Mamdouh; Eldesouky, Ashraf; Badr, Magdy; Hegab, Abd Elraouf; Balboula, Ahmed; Zaabel, Samy M

    2017-03-01

    The cryopreservation of germ cells is a major tool for the propagation of animals with desired genetic traits. Although cryopreservation of spermatozoa in some animals is effective, its effectiveness is variable. For example, cryopreservation efficiency of buffalo bull spermatozoa remains very poor. In this study, we evaluated sperm DNA damage and ultrastructure in buffalo bull spermatozoa vitrified in the presence or absence of cholesterol-loaded cyclodextrins (CLC). Our results showed that cryopreserved buffalo spermatozoa had elevated levels of deteriorated plasma and mitochondrial membranes, which are the likely causes of DNA damage after vitrification. Accordingly, the levels of the activity of Alanine Aminotransferase (ALT), Alkaline phosphatase (ALP) and Aspartate Aminotransferase (AST) were also elevated following exposure of buffalo bull spermatozoa to a cycle of freezing-thawing. Importantly, supplementation of Tris-Egg Yolk-Glucose (TEYG) extender with (CLC) improved the quality of buffalo spermatozoa following cryopreservation. This protective effect of CLC is likely due to decreasing mitochondrial and plasma membrane deterioration with subsequent inhibition of DNA damage. These results suggest that cholesterol loss is the likely reason for poor semen quality in buffaloes following cryopreservation, and provide evidence that manipulating lipid content during cryopreservation is a promising strategy to improve the quality of buffalo semen. Copyright © 2016. Published by Elsevier Urban & Partner Sp. z o.o.

  20. VITRIFICATION OF THAI NATIVE CATTLE OOCYTES: EFFECTS OF ETHYLENE GLYCOL CONCENTRATIONS AND EXPOSURE TIME, LINOLEIC ACID ALBUMIN AND CHOLESTEROL-LOADED METHYL-B-CYCLODEXTRIN.

    PubMed

    Chasombat, Jakkhaphan; Vongpralub, Thevin; Sirisathien, Saksiri; Phasuk, Yupin; Sonseeda, Pronjit

    2015-01-01

    The present study aimed to improve the oocyte vitrification procedure for preservation of Thai native cattle genetic resources. In Experiment I, oocytes were exposed to various doses (2%, 4% and 6%) of ethylene glycol (EG) in vitrification solution I (VS-I) for different equilibration times (10 or 20 min) before being exposed to VS-II and then subjected to vitrification. Experiment II was divided into two parts: (a) oocytes were matured in medium supplemented with linoleic acid albumin (LAA) (1% or 2%) and then vitrified; (b) matured oocytes were preincubated with cholesterol-loaded methyl-β-cyclodextrin (CLC) (1% or 2%) and then vitrified. Equilibration of oocytes by exposure to 6% EG in VS-I for 10 min (Experiment I), and in vitro maturation of immature oocytes in medium supplementation with 2% LAA (Experiment II) were the most effective methods; vitrified/thawed oocytes showed higher rates of survival and subsequent embryonic development compared with the other experimental groups.

  1. Size, density and cholesterol load of HDL predict microangiopathy, coronary artery disease and β-cell function in men with T2DM.

    PubMed

    Hermans, Michel P; Amoussou-Guenou, K Daniel; Bouenizabila, Evariste; Sadikot, Shaukat S; Ahn, Sylvie A; Rousseau, Michel F

    The role of high-density lipoprotein cholesterol (HDL-C) as modifiable risk factor for cardiovascular (CV) disease is increasingly debated, notwithstanding the finding that small-dense and dysfunctional HDL are associated with the metabolic syndrome and T2DM. In order to better clarify the epidemiological risk related to HDL of different size/density, without resorting to direct measures, it would seem appropriate to adjust HDL-C to the level of its main apolipoprotein (apoA-I), thereby providing an [HDL-C/apoA-I] ratio. The latter allows not only to estimate an average size for HDLs, but also to derive indices on particle number, cholesterol load, and density. So far, the potential usefulness of this ratio in diabetes is barely addressed. To this end, we sorted 488 male patients with T2DM according to [HDL-C/apoA-I] quartiles (Q), to determine how the ratio relates to cardiometabolic risk, β-cell function, glycaemic control, and micro- and macrovascular complications. Five lipid parameters were derived from the combined determination of HDL-C and apoA-I, namely HDL size; particle number; cholesterol load/particle; apoA-I/particle; and particle density. An unfavorable cardiometabolic profile characterized patients from QI and QII, in which HDLs were pro-atherogenic, denser and apoA-I-depleted. By contrast, QIII patients had an [HDL-C/apoA-I] ratio close to that of non-diabetic controls. QIV patients had better than average HDL size and composition, and in those patients whose [HDL-C/apoA-I] ratio was above normal, a more favorable phenotype was observed regarding lifestyle, anthropometry, metabolic comorbidities, insulin sensitivity, MetS score/severity, glycaemic control, and target-organ damage pregalence in small or large vessels. In conclusion, [HDL-C/apoA-I] and the resulting indices of HDL composition and functionality predict macrovascular risk and β-cell function decline, as well as overall microangiopathic risk, suggesting that this ratio could serve

  2. Protection of PC12 cells from chemical ischemia induced oxidative stress by Fagonia arabica.

    PubMed

    Satpute, Ravindra M; Kashyap, Rajpal S; Deopujari, Jayant Y; Purohit, Hemant J; Taori, Girdhar M; Daginawala, Hatim F

    2009-11-01

    Fagonia arabica (Zygophyllaceae) is an important Ayurvedic herb, grows throughout arid regions of India, has been widely used as a folk remedy by the indigenous people for its anti-inflammatory, analgesic and antipyretic effects. In the present study, antioxidant potential of F. arabica and the associated mechanism of antioxidant defence in rat pheochromocytoma (PC12) cells subjected to chemical ischemia was studied. Effect of total extract of F. arabica was studied for its antioxidant potential on the chemical ischemia induced PC12 cells. Alterations in the activities of cellular antioxidant enzymes (SOD, CAT, GSH-Px and GSH-R) were measured. Antioxidant potential of herb (ABTS), extent of lipid peroxidation (MDA and 4-HAE), total antioxidant status (TAS) and total glutathione (reduced, oxidized and their ratio) were evaluated. F. arabica scavenges the free radicals (ABTS(.)+), and showed a concentration dependent antioxidant activity, highest being at 1000 microg/ml. Its treatment with ischemic cells ameliorates the GSH and TAS levels and also helps the cells to restore the activities of the cellular antioxidative enzymes and also reduced the degree of lipid peroxidation. F. arabica scavenges the free radicals and attenuates oxidative stress mediated cell injury during ischemia.

  3. Protective effects of natrii sulfas on cerebral focal ischemia induced by MCAO in rats.

    PubMed

    Sohn, Youngjoo; Kang, Ho Chang; Kim, Kon Sik; Park, Sun-Min; Sohn, Nak-Won; Jung, Hyuk-Sang; Kim, Sung-Hoon

    2009-01-01

    This study examined the effect of Natrii sulfas, a treatment for stroke patients suffering constipation in Oriental medicine, on the physiological indices and brain edema of rats. Brain edema was induced by a middle cerebral artery occlusion (MCAO), Natrii sulfas was administered after the MCAO. At 3, 6, 15, 24, and 48 hours after reperfusion, the physiological indices such as the fecal weight, urine volume and water content in the stools were assessed. The edema index was measured 48 hours after reperfusion. At 48 hours, the expressions of iNOS, MMP9, VEGF, GFAP, Bax, Bcl-2, c-Fos, and HSP72 positive astrocytes were observed on the brain tissues by immunohistochemistry. Natrii sulfas significantly improved the decrease in fecal weight, urine volume and water content in the stool caused by the ischemic insult (p < 0.05) and attenuated the brain edema caused by the ischemia insult (p < 0.05). Natrii sulfas significantly down-regulated iNOS and MMP9 expressions and attenuated the astrocyte swelling due to brain edema in the penumbra of the cerebral cortex of MCAO rats. Natrii sulfas reduced the excess Bax and HSP72 expressions in ischemic brain, which was statistically significant in the penumbra of the cerebral cortex but not in the caudate putamen. These results suggest Natrii sulfas has a protective effect on ischemia-induced brain edema and improves the physiological symptoms.

  4. Enhanced autophagy signaling in diabetic rats with ischemia-induced seizures.

    PubMed

    Xia, Luoxing; Lei, Zhigang; Shi, Zhongshan; Guo, Dave; Su, Henry; Ruan, Yiwen; Xu, Zao C

    2016-07-15

    Seizures are among the most common neurological sequelae of stroke, and ischemic insult in diabetes notably increases the incidence of seizures. Recent studies indicated that autophagy influences the outcome of stroke and involved in epileptogenesis. However, the association of autophagy and post-ischemic seizures in diabetes remains unclear. The present study aimed to reveal the involvement of autophagy in the seizures following cerebral ischemia in diabetes. Diabetes was induced in adult male Wistar rats by intraperitoneal injection of streptozotocin (STZ). The diabetic rats were subjected to transient forebrain ischemia. The neuronal damage was assessed using hematoxylin-eosin staining. Western blotting and immunohistochemistry were performed to investigate the alteration of autophagy marker microtubule-associated protein light chain 1B (LC3B). The results showed that all diabetic animals developed seizures after ischemia. However, no apparent cell death was observed in the hippocampus of seizure rats 12h after the insult. The expression of LC3B was significantly enhanced in naïve animals after ischemia and was further increased in diabetic animals after ischemia. Immunofluorescence double-labeling study indicated that LC3B was mainly increased in neurons. Our study demonstrated, for the first time, that autophagy activity is significantly increased in diabetic animals with ischemia-induced seizures. Further studies are needed to explore the role of autophagy in seizure generation after ischemia in diabetic conditions.

  5. Effect of ATP-dependent channel modulators on ischemia-induced arrhythmia change depending on age and gender.

    PubMed

    Bozdogan, Ömer; Kaya, Salih Tunç; Yasar, Selçuk; Orallar, Hayriye

    2013-10-01

    The number of ATP-dependent potassium channels in myocardial cells has been previously shown to change depending on gender and age. Different effects of the ATP-dependent potassium channel blocker, glybenclamide and ATP-dependent potassium channel opener, pinacidil on ischemia or reperfusion-induced arrhythmia observed in various research might depend on different ages and genders of the animals used. The aim of this study is to research the effect of ATP-dependent potassium channel modulators on ischemia-induced arrhythmia in animals of different ages and genders. Sprague-Dawley rats of different ages and genders were used in this study. Ischemia was produced by the ligation of the left coronary artery for 30 min. Electrocardiogram (ECG), blood pressure, infarct area and blood glucose were determined during the 30 min of ischemia. An arrhythmia score from an ECG recorded during 30 min of ischemia was determined by examining the duration and type of arrhythmia. Different effects of glybenclamide and pinacidil on the arrhythmias were observed in male and female young and middle-age rats. Pinacidil decreased the infarct zone in younger female rats, but differences in the type and length of ischemia-induced arrhythmias between females and males disappeared in older age. The results of this study showed that the effect of ATP-dependent potassium channel modulators on ischemia-induced arrhythmia changed due to the age and gender of rats.

  6. High-resolution lipidomics coupled with rapid fixation reveals novel ischemia-induced signaling in the rat neurolipidome.

    PubMed

    Trépanier, Marc-Olivier; Eiden, Michael; Morin-Rivron, Delphine; Bazinet, Richard P; Masoodi, Mojgan

    2017-03-01

    The field of lipidomics has evolved vastly since its creation 15 years ago. Advancements in mass spectrometry have allowed for the identification of hundreds of intact lipids and lipid mediators. However, because of the release of fatty acids from the phospholipid membrane in the brain caused by ischemia, identifying the neurolipidome has been challenging. Microwave fixation has been shown to reduce the ischemia-induced release of several lipid mediators. Therefore, this study aimed to develop a method combining high-resolution tandem mass spectrometry (MS/MS), high-energy head-focused microwave fixation and statistical modeling, allowing for the measurement of intact lipids and lipid mediators in order to eliminate the ischemia-induced release of fatty acids and identify the rat neurolipidome. In this study, we demonstrated the ischemia-induced production of bioactive lipid mediators, and the reduction in variability using microwave fixation in combination with liquid chromatography (LC)-MS/MS. We have also illustrated for the first time that microwave fixation eliminates the alterations in intact lipid species following ischemia. While many phospholipid species were unchanged by ischemia, other intact lipid classes, such as diacylglycerol, were lower in concentration following microwave fixation compared to ischemia. © 2016 International Society for Neurochemistry.

  7. Cholesterol (image)

    MedlinePlus

    Cholesterol is a soft, waxy substance that is present in all parts of the body including the ... and obtained from animal products in the diet. Cholesterol is manufactured in the liver and is needed ...

  8. Cholesterol and lifestyle

    MedlinePlus

    Hyperlipidemia - cholesterol and lifestyle; CAD - cholesterol and lifestyle; Coronary artery disease - cholesterol and lifestyle; Heart disease - cholesterol and lifestyle; Prevention - cholesterol and lifestyle; Cardiovascular disease - ...

  9. Effects of 2,4-dinitrophenol on ischemia-induced blood-brain barrier disruption.

    PubMed

    Ennis, S R; Keep, R F

    2006-01-01

    This study examines the effect of 2,4-dinitrophenol (DNP), a mitochondrial uncoupling agent, during focal brain ischemia induced by middle cerebral artery (MCA) occlusion. Blood-brain barrier (BBB) disruption was assessed after 2 hours of occlusion with 2 hours of reperfusion or 4 hours of permanent occlusion by measurement of the influx rate constant (K(i)) for 3H-inulin in the MCA territory ipsi- and contralateral to the occlusion. Three experimental groups were examined: vehicle and 1 and 5 mg/kg DNP treated animals (given 30 minutes prior to occlusion). Four hours of permanent MCA occlusion only induced a modest increase in the K(i) for inulin in vehicle-treated animals (0.09 +/- 0.01 vs. 0.07 +/- 0.01 microL/g/min in contralateral tissue). Although 5 mg/kg DNP significantly increased this disruption (p < 0.01), this effect was relatively minor (0.14 +/- 0.02 microL/g/min). In contrast, DNP treatment in transient ischemia markedly increased barrier disruption. The ipsilateral K(i) for 3H-inulin were 0.15 +/- 0.04, 0.37 +/- 0.06, and 0.79 +/- 0.17 microL/g/min in vehicle, 1 mg/kg DNP and 5 mg/kg DNP groups, respectively. DNP did not induce barrier disruption in the contralateral hemisphere. Thus, while there is evidence that DNP can be neuroprotective, it has adverse effects on the BBB during ischemia, particularly with reperfusion. Considering the importance of naturally- or therapeutically-induced reperfusion in limiting brain damage, this may limit the utility of DNP and mitochondrial uncouplers as therapeutic agents.

  10. Antiangiogenic effect of angiotensin II type 2 receptor in ischemia-induced angiogenesis in mice hindlimb.

    PubMed

    Silvestre, Jean-Sébastien; Tamarat, Radia; Senbonmatsu, Takaaki; Icchiki, Toshihiro; Ebrahimian, Teni; Iglarz, Marc; Besnard, Sandrine; Duriez, Micheline; Inagami, Tadashi; Lévy, Bernard I

    2002-05-31

    This study examined the potential role of angiotensin type 2 (AT(2)) receptor on angiogenesis in a model of surgically induced hindlimb ischemia. Ischemia was produced by femoral artery ligature in both wild-type and AT(2) gene-deleted mice (Agtr2(-)/Y). After 28 days, angiogenesis was quantitated by microangiography, capillary density measurement, and laser Doppler perfusion imaging. Protein levels of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), Bax, and Bcl-2 were determined by Western blot analysis in hindlimbs. The AT(2) mRNA level (assessed by semiquantitative RT-PCR) was increased in the ischemic hindlimb of wild-type mice. Angiographic vessel density and laser Doppler perfusion data showed significant improvement in ischemic/nonischemic leg ratio, 1.9- and 1.7-fold, respectively, in Agtr2(-)/Y mice compared with controls. In ischemic leg of Agtr2(-)/Y mice, revascularization was associated with an increase in the antiapoptotic protein content, Bcl-2 (211% of basal), and a decrease (60% of basal) in the number of cell death, determined by TUNEL method. Angiotensin II treatment (0.3 mg/kg per day) raised angiogenic score, blood perfusion, and both VEGF and eNOS protein content in ischemic leg of wild-type control but did not modulate the enhanced angiogenic response observed in untreated Agtr2(-)/Y mice. Finally, immunohistochemistry analysis revealed that VEGF was mainly localized to myocyte, whereas eNOS-positive staining was mainly observed in the capillary of ischemic leg of both wild-type and AT(2)-deficient mice. This study demonstrates for the first time that the AT(2) receptor subtype may negatively modulate ischemia-induced angiogenesis through an activation of the apoptotic process.

  11. Myocardial Blood Flow Distribution during Ischemia-Induced Coronary Vasodilation in the Unanesthetized Dog

    PubMed Central

    Bache, Robert J.; Cobb, Frederick R.; Greenfield, Joseph C.

    1974-01-01

    This study was designed to determine whether coronary vasodilation distal to a flow-limiting coronary artery stenosis could result in redistribution of myocardial blood flow to produce subendocardial underperfusion. Studies were performed in 10 awake dogs chronically prepared with electromagnetic flow-meters and hydraulic occluders on the left circumflex coronary artery. Regional myocardial blood flow was measured using radionuclide-labeled microspheres, 7-10 μm in diameter, injected into the left atrium. A 5-s coronary artery occlusion was followed by reactive hyperemia with excess inflow of arterial blood effecting 375±20% repayment of the blood flow debt incurred during occlusion. When, after a 5-s occlusion, the occluder was only partially released to hold arterial inflow to the preocclusion level for 20 s before complete release, the delayed reactive hyperemia was augmented (mean blood flow repayment = 610±45%, P < 0.01). This augmentation of the reactive hyperemia suggested that ischemia was continuing during the interval of coronary vasodilation when coronary inflow was at the preocclusion level. Measurements of regional myocardial blood flow demonstrated that endocardial flow slightly exceeded epicardial flow during control conditions. When arterial inflow was limited to the preocclusion rate during vasodilation after a 5-s total coronary artery occlusion, however, flow to the subepicardial myocardium was increased at the expense of underperfusion of the subendocardial myocardium. Thus, in the presence of a flow-limiting proximal coronary artery stenosis, ischemia-induced coronary vasodilation resulted in redistribution of myocardial blood flow with production of subendocardial ischemia in the presence of a net volume of arterial inflow which, if properly distributed, would have been adequate to prevent myocardial ischemia. Images PMID:4279928

  12. Brown propolis attenuates cerebral ischemia-induced oxidative damage via affecting antioxidant enzyme system in mice.

    PubMed

    Bazmandegan, Gholamreza; Boroushaki, Mohammad Taher; Shamsizadeh, Ali; Ayoobi, Fatemeh; Hakimizadeh, Elham; Allahtavakoli, Mohammad

    2017-01-01

    Oxidative stress plays a critical role in ischemic brain injury. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) are the enzymes underlying the endogenous antioxidant mechanisms affected by stroke and are considered as oxidative stress biomarkers. Brown propolis (BP) is a bioactive natural product with a set of biological activities that in turn may differ depending on the area from which the substance is originated. The aim of this study was to investigate the effect of water-extracted brown propolis (WEBPs), from two regions of Iran, against cerebral ischemia-induced oxidative injury in a mouse model of stroke. Experimentally, the chemical characterization and total polyphenol content were determined using GC/MS and Folin-Ciocalteu assay respectively. Seventy-two adult male mice were randomly divided into the surgical sham group, control group (treated with vehicle), and four groups of WEBPs-treated animals. The WEBPs were administered at the doses of 100 and 200mg/kg IP, during four different time points. Oxidative stress biomarkers (SOD and GPx activity, SOD/GPx ratio), lipid peroxidation (LPO) index (malondialdehyde content) and infarct volume were measured 48h post stroke. Behavioral tests were evaluated 24 and 48h after stroke. WEBPs treatment resulted in significant restoration of antioxidant enzymes activity and a subsequent decrease in LPO as well as the infarct volume compared to the control group. Sensory-motor impairment and neurological deficits were improved significantly as well. These results indicate that Iranian BP confers neuroprotection on the stroke-induced neuronal damage via an antioxidant mechanism which seems to be mediated by the endogenous antioxidant system. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  13. Prevention of ischemia-induced myocardial platelet deposition by exogenous prostacyclin

    SciTech Connect

    Aherne, T.; Price, D.C.; Yee, E.S.; Hsieh, W.R.; Ebert, P.A.

    1986-07-01

    The antithrombotic effects of prostacyclin infusion on myocardial platelet deposition were studied in a canine model during and after global ischemia. Eleven isolated heart preparations were subjected to 1 hour of cardioplegic arrest under moderate hypothermia (27 to 28/sup 0/C), including a control group (n = 7) and a prostacyclin-treated group (n = 4). The hearts of four other dogs were continuously perfused for 180 minutes. Platelet deposition was measured at 15 minute intervals throughout the 3 hour study. Serial full-thickness myocardial biopsy specimens were analyzed for activity of /sup 111/In-labeled platelets with /sup 99m/Tc-labeled erythrocyte correction for tissue blood content. The pattern of platelet distribution was determined by scintiscans of each heart, taken with a gamma camera at the end of the 60 minute reperfusion period. Substantial myocardial platelet deposition was found in the control hearts after ischemia but not in the prostacyclin-treated group (p less than 0.05). Furthermore, prostacyclin infusion had a significant disaggregatory effect on intracoronary platelet deposits when the precardioplegic and postcardioplegic biopsy specimens were analyzed (p less than 0.05). Three hours of continuous perfusion did not increase tissue /sup 111/In-labeled platelet activity. Ex vivo images showed platelet deposition to be a diffuse patchy process with significantly more /sup 111/In activity in the endocardium than in the epicardium after global ischemia (p less than 0.05). These data show the potent antithrombotic properties of prostacyclin in preventing and disaggregating ischemia-induced intracoronary platelet deposition during and after cardioplegic arrest.

  14. Effects of L-propionylcarnitine on ischemia-induced myocardial dysfunction in men with angina pectoris.

    PubMed

    Bartels, G L; Remme, W J; Pillay, M; Schönfeld, D H; Kruijssen, D A

    1994-07-15

    To identify the effect of L-propionylcarnitine (LPC) on ischemia, 31 fasting, untreated male patients with left coronary artery disease were studied during 2 identical pacing stress tests 45 minutes before (atrial pacing test I [APST I]) and 15 minutes after (APST II) administration of 15 mg/kg of LPC or placebo. Hemodynamic, metabolic, and nuclear angiographic variables were studied before, during, and for 10 minutes after pacing. After LPC administration, arterial total carnitine levels increased from 47 +/- 1.7 mumol/liter (control) to 730 +/- 30 mumol/liter. Hemodynamic and metabolic variables were comparable in LPC and placebo during APSI I, and reproducible in placebo during both tests. Although LPC did not affect myocardial oxygen demand and supply, it diminished myocardial ischemia, indicated by a significant 12% and 50% reduction in ST-segment depression and left ventricular end-diastolic pressure, respectively, during APST II. Moreover, during APST II, left ventricular ejection fraction increased by 18% (p < 0.05 vs APST I). Furthermore, LPC improved recovery of myocardial function after pacing, with a reduction in the time to peak filling and a 21% increase in both peak ejection and filling rates 10 minutes after pacing (all p < 0.05). Thus, LPC prevents ischemia-induced ventricular dysfunction, not by affecting the myocardial oxygen supply-demand ratio but as a result of its intrinsic metabolic actions, increasing pyruvate dehydrogenase activity and flux through the citric acid cycle. Because it is well tolerated, it may be a valuable alternative or addition to available antiischemic therapy.

  15. Diminazene aceturate enhances ACE2 activity and attenuates ischemia-induced cardiac pathophysiology

    PubMed Central

    Qi, YanFei; Zhang, Juan; Cole-Jeffrey, Colleen T; Shenoy, Vinayak; Espejo, Andrew; Hanna, Mina; Song, Chunjuan; Pepine, Carl J; Katovich, Michael J; Raizada, Mohan K

    2013-01-01

    Angiotensin-converting enzyme 2 (ACE2) plays a critical role against myocardial infarction (MI). We hypothesized that activation of intrinsic ACE2 would be protective against ischemia-induced cardiac pathophysiology. Diminazine aceturate (DIZE), a small molecule ACE2 activator has been used to evaluate this hypothesis. DIZE (15 mg/kg/day, s.c.) was injected two days prior to MI surgery and continued throughout the study-period. MI rats showed a 62% decrease in fractional shortening (FS,%) [control (Con): 51.1 ± 3.2; DIZE alone (D) : 52.1 ± 3.2; MI (M): 19.1± 3.0], a 55% decrease in contractility (dP/dtmax mmHg/s) (Con: 9480 ± 425.3; D: 9585 ± 597.4; M: 4251 ± 657.7), and a 27% increase in ventricular hypertrophy [VH, mg/mm (Con: 26.5 ± 1.5; D: 26.9 ± 1.4; M: 33.4± 1.1)]. DIZE attenuated the MI-induced decrease in FS by 89%, improved dP/dtmax by 92%, and reversed VH by 18%. MI also significantly increased ACE and angiotensin type 1 receptor levels while decreased ACE2 activity by 40% (Con: 246.2 ± 25.1; D: 254.2 ± 20.6; M: 148.9 ± 29.2, RFU/min), which was reversed by DIZE treatment. Thus, DIZE treatment decreased the infarct area, attenuated LV remodeling post-MI and restored normal balance of the cardiac renin angiotensin system. Additionally, DIZE treatment increased circulating endothelial progenitor cells, increased engraftment of cardiac progenitor cells and decreased inflammatory cells in peri-infarct cardiac regions. All of the beneficial effects associated with DIZE treatment were abolished by C-16, an ACE2 inhibitor. Collectively, DIZE and DIZE-like small molecules may represent promising new therapeutic agents for MI. PMID:23959549

  16. Vitamin D Deficiency Exacerbates Experimental Stroke Injury and Dysregulates Ischemia-Induced Inflammation in Adult Rats

    PubMed Central

    Balden, Robyn; Selvamani, Amutha

    2012-01-01

    Vitamin D deficiency (VDD) is widespread and considered a risk factor for cardiovascular disease and stroke. Low vitamin D levels are predictive for stroke and more fatal strokes in humans, whereas vitamin D supplements are associated with decreased risk of all-cause mortality. Because VDD occurs with other comorbid conditions that are also independent risk factors for stroke, this study examined the specific effect of VDD on stroke severity in rats. Adult female rats were fed control or VDD diet for 8 wk and were subject to middle cerebral artery occlusion thereafter. The VDD diet reduced circulating vitamin D levels to one fifth (22%) of that observed in rats fed control chow. Cortical and striatal infarct volumes in animals fed VDD diet were significantly larger, and sensorimotor behavioral testing indicated that VDD animals had more severe poststroke behavioral impairment than controls. VDD animals were also found to have significantly lower levels of the neuroprotective hormone IGF-I in plasma and the ischemic hemisphere. Cytokine analysis indicated that VDD significantly reduced IL-1α, IL-1β, IL-2, IL-4, IFN-γ, and IL-10 expression in ischemic brain tissue. However, ischemia-induced IL-6 up-regulation was significantly higher in VDD animals. In a separate experiment, the therapeutic potential of acute vitamin D treatments was evaluated, where animals received vitamin D injections 4 h after stroke and every 24 h thereafter. Acute vitamin D treatment did not improve infarct volume or behavioral performance. Our data indicate that VDD exacerbates stroke severity, involving both a dysregulation of the inflammatory response as well as suppression of known neuroprotectants such as IGF-I. PMID:22408173

  17. Improved safety and efficacy of a lipid emulsion loaded with a paclitaxel-cholesterol complex for the treatment of breast tumors.

    PubMed

    Ye, Jun; Liu, Yuling; Xia, Xuejun; Meng, Luhua; Dong, Wujun; Wang, Renyun; Fu, Zhaodi; Liu, Hongyan; Han, Rui

    2016-07-01

    The aim of the present study was to develop a lipid emulsion loaded with a paclitaxel-cholesterol complex (PTX-CH Emul) in order to improve the safety and efficacy of paclitaxel (PTX) and evaluate its antitumor activity against commercially available formulation Taxol®. PTX-CH Emul resembling a low density lipoprotein lipid structure, exhibited an ideal particle size, high drug loading capability, high drug encapsulation efficiency and excellent stability. PTX-CH Emul showed superior in vitro anticancer efficacy against triple-negative MDA-MB-231 breast cancer cells when compared with a paclitaxel emulsion (PTX Emul) and Taxol. The IC70 value of PTX-CH Emul was almost 1.5- and 2.4-fold lower than that of PTX Emul and Taxol, respectively. Compared with PTX Emul and Taxol, PTX-CH Emul exhibited stronger and more rapid inhibitory effects on 3D tumor spheroids of MDA-MB-231 cells. Additionally, in vivo tumor-targeting study showed that PTX-CH Emul had higher specificity and efficiency in intratumoral accumulation as compared to PTX Emul. Finally, the maximum tolerated dose (MTD) of PTX-CH Emul was 2.25‑fold higher than that of Taxol, suggesting that PTX-CH Emul exhibited better safety profiles in vivo than Taxol. At the MTDs, PTX-CH Emul exhibited superior antitumor efficacy in nude mice bearing MDA-MB-231 xenografts in comparison to Taxol. Therefore, PTX-CH Emul as reported here showed high potential as a drug carrier for PTX in clinical applications involving the targeting of triple-negative breast cancer.

  18. Validated HPLC Method for the Determination of Paclitaxel-related Substances in an Intravenous Emulsion Loaded with a Paclitaxel–Cholesterol Complex

    PubMed Central

    Xia, X. J.; Peng, J.; Zhang, P. X.; Jin, D. J.; Liu, Y. L.

    2013-01-01

    A high-performance liquid chromatography method was developed for the determination of related substances in an intravenous emulsion loaded with a paclitaxel–cholesterol complex. The separation was achieved using Agilent Eclipse XDB-C18 column (150×4.6 mm, 3.5 μm), which was kept at 40°. The gradient mobile phase consisted of acetonitrile and water with a flow rate of 1.2 ml/min. The ultraviolet detection wavelength was set at 227 nm. The preparation of the sample solution began with the addition of anhydrous sodium sulphate to break the emulsion. Then, methanol and ethyl ether were added to pick up the drug and remove the accessories of the emulsion by extraction and centrifugation. Finally, paclitaxel was enriched by a nitrogen blow method and resolved with a mixture of methanol:glacial acetic acid (200:1). The method was proven to be selective, sensitive, robust, linear, repeatable, accurate and suitable for the determination of paclitaxel-related substances in the emulsion formulations, and the major degradation products in the potential pharmaceutical product were 7-epipaclitaxel and 10-deacetylpaclitaxel. PMID:24591742

  19. PEP-1-CAT-Transduced Mesenchymal Stem Cells Acquire an Enhanced Viability and Promote Ischemia-Induced Angiogenesis

    PubMed Central

    Zhang, Lei; Dong, Xiao-Wei; Wang, Jia-Ning; Tang, Jun-Ming; Yang, Jian-Ye; Guo, Ling-Yun; Zheng, Fei; Kong, Xia; Huang, Yong-Zhang; Chen, Shi-You

    2012-01-01

    Objective Poor survival of mesenchymal stem cells (MSC) compromised the efficacy of stem cell therapy for ischemic diseases. The aim of this study is to investigate the role of PEP-1-CAT transduction in MSC survival and its effect on ischemia-induced angiogenesis. Methods MSC apoptosis was evaluated by DAPI staining and quantified by Annexin V and PI double staining and Flow Cytometry. Malondialdehyde (MDA) content, lactate dehydrogenase (LDH) release, and Superoxide Dismutase (SOD) activities were simultaneously measured. MSC mitochondrial membrane potential was analyzed with JC-1 staining. MSC survival in rat muscles with gender-mismatched transplantation of the MSC after lower limb ischemia was assessed by detecting SRY expression. MSC apoptosis in ischemic area was determined by TUNEL assay. The effect of PEP-1-CAT-transduced MSC on angiogenesis in vivo was determined in the lower limb ischemia model. Results PEP-1-CAT transduction decreased MSC apoptosis rate while down-regulating MDA content and blocking LDH release as compared to the treatment with H2O2 or CAT. However, SOD activity was up-regulated in PEP-1-CAT-transduced cells. Consistent with its effect on MSC apoptosis, PEP-1-CAT restored H2O2-attenuated mitochondrial membrane potential. Mechanistically, PEP-1-CAT blocked H2O2-induced down-regulation of PI3K/Akt activity, an essential signaling pathway regulating MSC apoptosis. In vivo, the viability of MSC implanted into ischemic area in lower limb ischemia rat model was increased by four-fold when transduced with PEP-1-CAT. Importantly, PEP-1-CAT-transduced MSC significantly enhanced ischemia-induced angiogenesis by up-regulating VEGF expression. Conclusions PEP-1-CAT-transduction was able to increase MSC viability by regulating PI3K/Akt activity, which stimulated ischemia-induced angiogenesis. PMID:23285080

  20. Mitogen and stress-activated kinases 1/2 regulate ischemia-induced hippocampal progenitor cell proliferation and neurogenesis

    PubMed Central

    Karelina, Kate; Liu, Yujia; Alzate-Correa, Diego; Wheaton, Kelin L.; Hoyt, Kari R.; Arthur, J. Simon C.; Obrietan, Karl

    2016-01-01

    Pathophysiological conditions such as cerebral ischemia trigger the production of new neurons from the neurogenic niche within the subgranular zone (SGZ) of the dentate gyrus. The functional significance of ischemia-induced neurogenesis is believed to be the regeneration of lost cells, thus contributing to post-ischemia recovery. However, the cell signaling mechanisms by which this process is regulated are still under investigation. Here, we investigated the role of mitogen and stress-activated protein kinases (MSK1/2) in the regulation of progenitor cell proliferation and neurogenesis after cerebral ischemia. Using the endothelin-1 model of ischemia, wild type (WT) and MSK1−/−/MSK2−/− (MSK dKO) mice were injected with BrdU and sacrificed 2 days, 4 weeks, or 6 weeks later for the analysis of progenitor cell proliferation, neurogenesis, and neuronal morphology, respectively. We report a decrease in SGZ progenitor cell proliferation in MSK dKO mice compared to WT mice. Moreover, MSK dKO mice exhibited reduced neurogenesis and a delayed maturation of ischemia-induced newborn neurons. Further, structural analysis of neuronal arborization revealed reduced branching complexity in MSK dKO compared to WT mice. Taken together, this dataset suggests that MSK1/2 plays a significant role in the regulation of ischemia-induced progenitor cell proliferation and neurogenesis. Ultimately, revealing the cell signaling mechanisms that promote neuronal recovery will lead to novel pharmacological approaches for the treatment of neurodegenerative diseases such as cerebral ischemia. PMID:25451279

  1. Mitogen and stress-activated kinases 1/2 regulate ischemia-induced hippocampal progenitor cell proliferation and neurogenesis.

    PubMed

    Karelina, K; Liu, Y; Alzate-Correa, D; Wheaton, K L; Hoyt, K R; Arthur, J S C; Obrietan, K

    2015-01-29

    Pathophysiological conditions such as cerebral ischemia trigger the production of new neurons from the neurogenic niche within the subgranular zone (SGZ) of the dentate gyrus. The functional significance of ischemia-induced neurogenesis is believed to be the regeneration of lost cells, thus contributing to post-ischemia recovery. However, the cell signaling mechanisms by which this process is regulated are still under investigation. Here, we investigated the role of mitogen and stress-activated protein kinases (MSK1/2) in the regulation of progenitor cell proliferation and neurogenesis after cerebral ischemia. Using the endothelin-1 model of ischemia, wild-type (WT) and MSK1(-/-)/MSK2(-/-) (MSK dKO) mice were injected with BrdU and sacrificed 2 days, 4 weeks, or 6 weeks later for the analysis of progenitor cell proliferation, neurogenesis, and neuronal morphology, respectively. We report a decrease in SGZ progenitor cell proliferation in MSK dKO mice compared to WT mice. Moreover, MSK dKO mice exhibited reduced neurogenesis and a delayed maturation of ischemia-induced newborn neurons. Further, structural analysis of neuronal arborization revealed reduced branching complexity in MSK dKO compared to WT mice. Taken together, this dataset suggests that MSK1/2 plays a significant role in the regulation of ischemia-induced progenitor cell proliferation and neurogenesis. Ultimately, revealing the cell signaling mechanisms that promote neuronal recovery will lead to novel pharmacological approaches for the treatment of neurodegenerative diseases such as cerebral ischemia. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  2. Catalpol Protects Pre-Myelinating Oligodendrocytes against Ischemia-induced Oxidative Injury through ERK1/2 Signaling Pathway

    PubMed Central

    Cai, Qiyan; Ma, Teng; Li, Chengren; Tian, Yanping; Li, Hongli

    2016-01-01

    The vulnerability of pre-myelinating oligodendrocytes (PreOLs) to ischemic injury plays an important role in the pathogenesis and progression of perinatal white matter injury. Although oxidative stress is thought to be a major pathogenic mechanism predisposing the PreOLs to injury, no effective therapies have been identified to date. The present study aimed to investigate the direct protective effects of catalpol, a potent antioxidant and free radical scavenger, on ischemia-induced oxidative damage in PreOLs and to explore whether the ERK1/2 signaling pathway contributed to the protection provided by catalpol. Primary cultures of PreOLs exposed to oxygen-glucose deprivation (OGD) followed by reperfusion were used as an in vitro model of ischemia. Pretreatment with 0.5 mM catalpol for 1 h prior to OGD treatment significantly reversed ischemia-induced apoptosis in PreOLs and myelination deficits by inhibiting intracellular Ca2+ increase, reducing mitochondrial damage, and ameliorating overproduction of reactive oxygen species (ROS). The expression levels of phosphorylated ERK1/2 (p-ERK1/2) and activated poly-ADP-ribose polymerase-1 (PARP-1) were also markedly decreased by catalpol treatment. Blocking the ERK1/2 signaling pathway with the MEK inhibitor U0126 and catalpol significantly protected PreOLs from ROS-mediated apoptosis under OGD. Taken together, these results suggest that catalpol protects PreOLs against ischemia-induced oxidative injury through ERK1/2 signaling pathway. Catalpol may be a candidate for treating ischemic white matter damage. PMID:27994507

  3. Magnesium Sulfate Prevents Placental Ischemia-Induced Increases in Brain Water Content and Cerebrospinal Fluid Cytokines in Pregnant Rats

    PubMed Central

    Zhang, Linda W.; Warrington, Junie P.

    2016-01-01

    Magnesium sulfate (MgSO4) is the most widely used therapy in the clinic to prevent the progression of preeclampsia, a hypertensive disorder of pregnancy, to eclampsia. Eclampsia, manifested as unexplained seizures and/or coma during pregnancy or postpartum, accounts for ~13% of maternal deaths worldwide. While MgSO4 continues to be used in the clinic, the mechanisms by which it exerts its protective actions are not well understood. In this study, we tested the hypothesis that MgSO4 protects against placental ischemia-induced increases in brain water content and cerebrospinal fluid cytokines. To test this hypothesis, MgSO4 was administered via mini-osmotic pump (60 mg/day, i.p.) to pregnant and placental ischemic rats, induced by mechanical reduction of uterine perfusion pressure, from gestational day 14–19. This treatment regimen of MgSO4 led to therapeutic level of 2.8 ± 0.6 mmol/L Mg in plasma. MgSO4 had no effect on improving placental ischemia-induced changes in mean arterial pressure, number of live fetuses, or fetal and placental weight. Placental ischemia increased, while MgSO4 prevented the increase in water content in the anterior cerebrum. Cytokine and chemokine levels were measured in the cerebrospinal fluid using a multi-plex assay. Results demonstrate that cerebrospinal fluid, obtained via the cisterna magna, had reduced protein, albumin, interleukin (IL)-17A, IL-18, IL-2, eotaxin, fractalkine, interferon gamma, vascular endothelial growth factor (VEGF), and macrophage inflammatory protein (MIP)-2 following MgSO4 treatment. These data support the hypothesis that MgSO4 offers neuroprotection by preventing placental ischemia-induced cerebral edema and reducing levels of cytokines/chemokines in the cerebrospinal fluid. PMID:28008305

  4. PET imaging of ischemia-induced impairment of mitochondrial complex I function in monkey brain

    PubMed Central

    Tsukada, Hideo; Ohba, Hiroyuki; Nishiyama, Shingo; Kanazawa, Masakatsu; Kakiuchi, Takeharu; Harada, Norihiro

    2014-01-01

    To assess the capability of 18F-2-tert-butyl-4-chloro-5-{6-[2-(2-fluoroethoxy)-ethoxy]-pyridin-3-ylmethoxy}-2H-pyridazin-3-one (18F-BCPP-EF), a novel positron emission tomography (PET) probe for mitochondrial complex I (MC-I) activity, as a specific marker of ischemia-induced neuronal death without being disturbed by inflammation, translational research was conducted using an animal PET in ischemic brains of Cynomolgus monkeys (Macaca fascicularis). Focal ischemia was induced by the right middle cerebral artery occlusion for 3 hours, then PET scans were conducted at Day-7 with 15O-gases for regional cerebral blood flow (rCBF) and regional cerebral metabolism of oxygen (rCMRO2), and 18F-BCPP-EF for MC-I with arterial blood sampling. On Day-8, the additional PET scans conducted with 11C-flumazenil (11C-FMZ) for central-type benzodiazepine receptors, 11C-PBR28 for translocator protein, and 18F-fluoro-2-deoxy-D-glucose (18F-FDG) for regional cerebral metabolic rate of glucose (rCMRglc). The total distribution volume (VT) values of 18F-BCPP-EF showed the significant reduction in MC-I activity in the damaged area at Day-7. When correlated with rCBF and rCMRO2, the VT values of 18F-BCPP-EF provided better correlation with rCMRO2 than with rCBF. In the inflammatory regions (region of interest, ROIPBR) of the ischemic hemisphere detected with 11C-PBR28, higher 18F-FDG uptake and lower VT of 18F-BCPP-EF, 11C-FMZ, and rCMRO2 than those in normal contralateral hemisphere were observed. These results strongly suggested that 18F-BCPP-EF could discriminate the neuronal damaged areas with neuroinflammation, where 18F-FDG could not owing to its high uptake into the activated microglia. PMID:24447952

  5. CXCL12 Gene Therapy Ameliorates Ischemia-Induced White Matter Injury in Mouse Brain.

    PubMed

    Li, Yaning; Tang, Guanghui; Liu, Yanqun; He, Xiaosong; Huang, Jun; Lin, Xiaojie; Zhang, Zhijun; Yang, Guo-Yuan; Wang, Yongting

    2015-10-01

    Remyelination is an important repair process after ischemic stroke-induced white matter injury. It often fails because of the insufficient recruitment of oligodendrocyte progenitor cells (OPCs) to the demyelinated site or the inefficient differentiation of OPCs to oligodendrocytes. We investigated whether CXCL12 gene therapy promoted remyelination after middle cerebral artery occlusion in adult mice. The results showed that CXCL12 gene therapy at 1 week after ischemia could protect myelin sheath integrity in the perifocal region, increase the number of platelet-derived growth factor receptor-α (PDGFRα)-positive and PDGFRα/bromodeoxyuridine-double positive OPCs in the subventricular zone, and further enhance their migration to the ischemic lesion area. Coadministration of AMD3100, the antagonist for CXCL12 receptor CXCR4, eliminated the beneficial effect of CXCL12 on myelin sheath integrity and negatively influenced OPC proliferation and migration. At 5 weeks after ischemia, CXCR4 was found on the PDGFRα- and/or neuron/glia type 2 (NG2)-positive OPCs but not on the myelin basic protein-positive mature myelin sheaths, and CXCR7 was only expressed on the mature myelin sheath in the ischemic mouse brain. Our data indicated that CXCL12 gene therapy effectively protected white matter and promoted its repair after ischemic injury. The treatment at 1 week after ischemia is effective, suggesting that this strategy has a longer therapeutic time window than the treatments currently available. This study has demonstrated for the first time that CXCL12 gene therapy significantly ameliorates brain ischemia-induced white matter injury and promotes oligodendrocyte progenitor cell proliferation in the subventricular zone and migration to the perifocal area in the ischemic mouse brain. Additional data showed that CXCR4 receptor plays an important role during the proliferation and migration of oligodendrocyte progenitor cells, and CXCR7 might play a role during maturation. In

  6. Systemic dendrimer-drug treatment of ischemia-induced neonatal white matter injury.

    PubMed

    Nance, Elizabeth; Porambo, Michael; Zhang, Fan; Mishra, Manoj K; Buelow, Markus; Getzenberg, Rachel; Johnston, Michael; Kannan, Rangaramanujam M; Fatemi, Ali; Kannan, Sujatha

    2015-09-28

    Extreme prematurity is a major risk factor for perinatal and neonatal brain injury, and can lead to white matter injury that is a precursor for a number of neurological diseases, including cerebral palsy (CP) and autism. Neuroinflammation, mediated by activated microglia and astrocytes, is implicated in the pathogenesis of neonatal brain injury. Therefore, targeted drug delivery to attenuate neuroinflammation may greatly improve therapeutic outcomes in models of perinatal white matter injury. In this work, we use a mouse model of ischemia-induced neonatal white matter injury to study the biodistribution of generation 4, hydroxyl-functionalized polyamidoamine dendrimers. Following systemic administration of the Cy5-labeled dendrimer (D-Cy5), we demonstrate dendrimer uptake in cells involved in ischemic injury, and in ongoing inflammation, leading to secondary injury. The sub-acute response to injury is driven by astrocytes. Within five days of injury, microglial proliferation and migration occurs, along with limited differentiation of oligodendrocytes and oligodendrocyte death. From one day to five days after injury, a shift in dendrimer co-localization occurred. Initially, dendrimer predominantly co-localized with astrocytes, with a subsequent shift towards microglia. Co-localization with oligodendrocytes reduced over the same time period, demonstrating a region-specific uptake based on the progression of the injury. We further show that systemic administration of a single dose of dendrimer-N-acetyl cysteine conjugate (D-NAC) at either sub-acute or delayed time points after injury results in sustained attenuation of the 'detrimental' pro-inflammatory response up to 9days after injury, while not impacting the 'favorable' anti-inflammatory response. The D-NAC therapy also led to improvement in myelination, suggesting reduced white matter injury. Demonstration of treatment efficacy at later time points in the postnatal period provides a greater understanding of how

  7. Ischemia induces partial loss of surface membrane polarity and accumulation of putative calcium ionophores.

    PubMed Central

    Molitoris, B A; Wilson, P D; Schrier, R W; Simon, F R

    1985-01-01

    To determine if ischemia induces alterations in renal proximal tubule surface membranes, brush border (BBM) and basolateral membranes (BLM) were isolated simultaneously from the same cortical homogenate after 50 min of renal pedicle clamping. Ischemia caused a selective decrease in the specific activity of BBM marker enzymes leucine aminopeptidase and alkaline phosphatase, but did not effect enrichment (15 times). Neither specific activity nor enrichment (10 times) of BLM NaK-ATPase was altered by ischemia. Contamination of BBM by intracellular organelles was also unchanged, but there was an increase in the specific activity (41.1 vs. 60.0, P less than 0.01) and enrichment (2.3 vs. 4.3, P less than 0.01) of NaK-ATPase in the ischemic BBM fraction. Ischemia increased BLM lysophosphatidylcholine (1.3 vs. 2.5%, P less than 0.05) and phosphatidic acid (0.4 vs. 1.3%, P less than 0.05). Ischemia also decreased BBM sphingomyelin (38.5 vs. 29.6%, P less than 0.01) and phosphatidylserine (16.1 vs. 11.4%, P less than 0.01), and increased phosphatidylcholine (17.2 vs. 29.7%, P less than 0.01), phosphatidylinositol (1.8 vs. 4.6%, P less than 0.01), and lysophosphatidylcholine (1.0 vs. 1.8%, P less than 0.05). The large changes in BBM phospholipids did not result from new phospholipid synthesis, since the specific activity (32P dpm/nmol Pi) of prelabeled individual and total phospholipids was unaltered by ischemia. We next evaluated if these changes were due to inability of ischemic cells to maintain surface membrane polarity. Cytochemical evaluation showed that while NaK-ATPase could be detected only in control BLM, specific deposits of reaction product were present in the BBM of ischemic kidneys. Furthermore, using continuous sucrose gradients, the enzymatic profile of ischemic BBM NaK-ATPase shifted away from ischemic BLM NaK-ATPase and toward the BBM enzymatic marker leucine aminopeptidase. Taken together, these data suggest that NaK-ATPase activity determined enzymatically

  8. Good vs. Bad Cholesterol

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More Good vs. Bad Cholesterol Updated:Apr 3,2017 Cholesterol can't dissolve ... test . View an animation of cholesterol . LDL (Bad) Cholesterol LDL cholesterol is considered the “bad” cholesterol because ...

  9. What's Cholesterol?

    MedlinePlus

    ... ve ever gone to the grocery store or food market, you've probably seen foods with labels on them that say "low in ... body. You also can get cholesterol from the foods you eat. Meat, fish, eggs, butter, cheese, and whole or low-fat milk all have cholesterol in ...

  10. Phosphatidylcholine: Greasing the Cholesterol Transport Machinery

    PubMed Central

    Lagace, Thomas A.

    2015-01-01

    Negative feedback regulation of cholesterol metabolism in mammalian cells ensures a proper balance of cholesterol with other membrane lipids, principal among these being the major phospholipid phosphatidylcholine (PC). Processes such as cholesterol biosynthesis and efflux, cholesteryl ester storage in lipid droplets, and uptake of plasma lipoproteins are tuned to the cholesterol/PC ratio. Cholesterol-loaded macrophages in atherosclerotic lesions display increased PC biosynthesis that buffers against elevated cholesterol levels and may also facilitate cholesterol trafficking to enhance cholesterol sensing and efflux. These same mechanisms could play a generic role in homeostatic responses to acute changes in membrane free cholesterol levels. Here, I discuss the established and emerging roles of PC metabolism in promoting intracellular cholesterol trafficking and membrane lipid homeostasis. PMID:27081313

  11. TNF-α is Critical for Ischemia-induced Leukostasis, But Not Retinal Neovascularization nor VEGF-induced Leakage

    PubMed Central

    Vinores, Stanley A.; Xiao, Wei-Hong; Shen, JiKui; Campochiaro, Peter.A.

    2007-01-01

    Vascular endothelial growth factor (VEGF) and tumor necrosis factor-α (TNF-α) show significant overlap with regard to their effects in the eye. It has been postulated that VEGF-induced leukostasis, breakdown of the blood-retinal barrier, and ischemia-induced retinal neovascularization may be mediated, at least in part, through TNF-α. In this study, we used mice deficient in TNF-α to test our hypothesis. Compared to wild type mice, TNF-α-deficient mice showed an 80% reduction in leukocyte accumulation in retinal vessels after intravitreous injection of VEGF, and 100% reductions after intravitreous injections of interleukin-1β (IL-1β) or platelet-activating factor (PAF). The increase in retinal vascular permeability induced by injection of PAF was significantly reduced in mice lacking TNF-α, but VEGF- and IL-1β-induced leakage was unaffected. Compared to wild type mice with oxygen-induced ischemic retinopathy, TNF-α-deficient mice with ischemic retinopathy showed significantly reduced leukostasis and mild reduction in vascular leakage, but no significant difference in retinal neovascularization. These data suggest that TNF-α mediates VEGF-, IL-1β-, and PAF-induced leukostasis and vascular leakage mediated by PAF, but not leakage caused by VEGF or IL-1β. Ischemia-induced retinal neovascularization, which has previously been shown to require VEGF, does not require TNF-α and is unaffected by attenuation of leukostasis. PMID:17107717

  12. Targeted ablation of cardiac sympathetic neurons reduces the susceptibility to ischemia-induced sustained ventricular tachycardia in conscious rats

    PubMed Central

    Lujan, Heidi L.; Palani, Gurunanthan; Zhang, Lijie

    2010-01-01

    The Cardiac Arrhythmia Suppression Trial demonstrated that antiarrhythmic drugs not only fail to prevent sudden cardiac death, but actually increase overall mortality. These findings have been confirmed in additional trials. The “proarrhythmic” effects of most currently available antiarrhythmic drugs makes it essential that we investigate novel strategies for the prevention of sudden cardiac death. Targeted ablation of cardiac sympathetic neurons may become a therapeutic option by reducing sympathetic activity. Thus cholera toxin B subunit (CTB) conjugated to saporin (a ribosomal inactivating protein that binds to and inactivates ribosomes; CTB-SAP) was injected into both stellate ganglia to test the hypothesis that targeted ablation of cardiac sympathetic neurons reduces the susceptibility to ischemia-induced, sustained ventricular tachycardia in conscious rats. Rats were randomly divided into three groups: 1) control (no injection); 2) bilateral stellate ganglia injection of CTB; and 3) bilateral stellate ganglia injection of CTB-SAP. CTB-SAP rats had a reduced susceptibility to ischemia-induced, sustained ventricular tachycardia. Associated with the reduced susceptibility to ventricular arrhythmias were a reduced number of stained neurons in the stellate ganglia and spinal cord (segments T1-T4), as well as a reduced left ventricular norepinephrine content and sympathetic innervation density. Thus CTB-SAP retrogradely transported from the stellate ganglia is effective at ablating cardiac sympathetic neurons and reducing the susceptibility to ventricular arrhythmias. PMID:20173045

  13. Ischemia-induced alterations in myocardial (Na+ + K+)-ATPase and cardiac glycoside binding.

    PubMed Central

    Beller, G A; Conroy, J; Smith, T W

    1976-01-01

    The effects of ischemia on the canine myocardial (Na+ + K+)-ATPase complex were examined in terms of alterations in cardiac glycoside binding and enzymatic activity. Ability of the myocardial cell to bind tritiated ouabain in vivo was assessed after 1, 2, and 6 h of coronary occlusion followed by 45 min of reperfusion, and correlated with measurements of in vitro (Na+ + K+)-ATPase activity and in vitro [3H]ouabain binding after similar periods of ischemia. Regional blood flow alterations during occlusion and reperfusion were simultaneously determined utilizing 15 mum radioactive microspheres to determine the degree to which altered binding of ouabain might be flow related. Anterior wall infarction was produced in 34 dogs by snaring of confluent branches of the left coronary system. Epicardial electrograms delineated ischemic and border zone areas. Coronary reperfusion after 2 and 6 h of occlusion was associated with impaired reflow of blood and markedly impaired uptake of [3H]ouabain in ischemic myocardium. In both groups, in vivo [3H]ouabain binding by ischemic tissue was reduced out of proportion to the reduction in flow. Despite near-complete restoration of flow in seven dogs occluded for 1 h and reperfused, [3H]ouabain remained significantly reduced to 58 +/- 9% of nonischemic uptake in subendocardial layers of the central zone of ischemia. Thus, when coronary flow was restored to areas of myocardium rendered acutely ischemia for 1 or more hours, ischemic zones demonstrated progressively diminished ability to bind ouabain. To determine whether ischemia-induced alteration in myocardial (Na+ + K+)-ATPase might underlie these changes, (Na+ + K+)-ATPase activity and [3H]ouabain binding were measured in microsomal fractions from ischemic myocardium after 1, 2, and 6 h of coronary occlusion. In animals occluded for 6 h, (Na+ + K+)-ATPase activity was significantly reduced by 40% in epicardial and by 35% in endocardial layers compared with nonischemic myocardium

  14. Cholesterol Levels

    MedlinePlus

    ... diet or exercise routine. References American Heart Association [Internet]. Dallas (TX): American Heart Association Inc.; c2017. About ... Cholesterol_UCM_001220_Article.jsp American Heart Association [Internet]. Dallas (TX): American Heart Association Inc.; c2017. Good ...

  15. Cholesterol and Statins

    MedlinePlus

    ... from you cholesterol is important Cholesterol has a bad rap. In reality, your body needs cholesterol to ... low-cholesterol diet should help lower your LDL (bad cholesterol). If it’s not lowered enough by reducing ...

  16. Combined training (strength plus aerobic) potentiates a reduction in body fat but only functional training reduced low-density lipoprotein cholesterol in postmenopausal women with a similar training load.

    PubMed

    Rossi, Fabrício Eduardo; Fortaleza, Ana Claudia S; Neves, Lucas M; Diniz, Tiego A; de Castro, Marcela R; Buonani, Camila; Mota, Jorge; Freitas, Ismael F

    2017-06-01

    The aim of this study was to compare the effects of combined (CT; strength plus aerobic) and functional training (FT) on the body composition and metabolic profile with a similar training load in postmenopausal women. The participants were divided into three groups: CT (n=20), FT (n=17), and control group (CG, n=15). The trunk FM, fat mass (FM), percentage of FM (FM%), and fat-free mass were estimated by dual-energy X-ray absorptiometry. The metabolic profile, glucose, triacylglycerol, total cholesterol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol (LDL-c) were assessed. There were main effects of time in trunk fat, FM, and FM% (P<0.05). There were statistically significant interaction for FM (P=0.015), FM% (P=0.017) with lower values for CT group. For LDL-c, there was significant interaction (P=0.002) with greater values for FT group in relation to CG and CT. Furthermore, when performed the post hoc test on the "mean absolute differences" (Δ), it can observed statistically significant difference between FT, CT, and CG (-13.0±16.5 mg/dL vs. 4.8±18.4 mg/dL vs. 9.2±18.8 mg/dL, P<0.05). In conclusion, when training loads are equivalent CT potentiated a reduction in FM and FM%, however, only FT reduced LDL-c in postmenopausal women.

  17. Low O2 and high CO2 in LLC-PK1 cells culture mimics renal ischemia-induced apoptosis.

    PubMed

    Hotter, Gina; Palacios, Luis; Sola, Anna

    2004-02-01

    Ischemia, absence or loss of blood flow in organs always presents as a dual phenomenon: tissue oxygen deficit and CO(2) excess (hypercapnia). Commonly hypoxic cell culture models kept CO(2) at normal nonischemic values. We report a study of apoptosis in an in vitro model of renal hypoxia that mimics in vivo tissue gas atmosphere composition determined during experimental ischemia in rat kidney (low O(2) plus high CO(2)). Renal tubular LLC-PK1 cell were transiently exposed to hypoxia, to hypercapnia or to both conditions (simulated ischemia). Exposure to simulated ischemic atmosphere, but not to low O(2) or high CO(2) alone, induced cell apoptosis in vitro. This suggests that ischemia-induced apoptosis in vivo would be dependent on the natural, joint action of hypoxia and hypercapnia. This should be taken into account in cell culture studies that would like to mimic in vivo ischemic conditions.

  18. Nobiletin improves brain ischemia-induced learning and memory deficits through stimulation of CaMKII and CREB phosphorylation.

    PubMed

    Yamamoto, Yui; Shioda, Norifumi; Han, Feng; Moriguchi, Shigeki; Nakajima, Akira; Yokosuka, Akihito; Mimaki, Yoshihiro; Sashida, Yutaka; Yamakuni, Tohru; Ohizumi, Yasushi; Fukunaga, Kohji

    2009-10-27

    Decreased cerebral blood flow causes cognitive impairments and neuronal injury in the progressive age-related neurodegenerative disorders such as Alzheimer's disease (AD) and vascular dementia. In the present study, we for the first time found that nobiletin, a novel leading compound for AD therapy, improved cerebral ischemia-induced memory deficits in vivo. Treatment with 50 mg/kg of nobiletin (i.p.) for the consecutive 7 days before and after brain ischemia significantly inhibited delayed neuronal death in the hippocampal CA1 neurons in a 20-min bilateral common carotid arteries occlusion (BCCAO) ischemia. However, the contextual memory assessed by passive avoidance task was not improved. On the other hand, a 5-min BCCAO-induced contextual memory deficit was significantly improved by the nobiletin treatment. In the 5-min BCCAO mice, Western blot analysis evidently showed that the levels of synaptic proteins, including calcium/calmodulin-dependent protein kinase II (CaMKII), microtubule-associated protein 2 (MAP2) and glutamate receptor 1 (GluR1), significantly decreased in the hippocampal CA1 region. The nobiletin treatment prevented the reduction in CaMKII, MAP2 and GluR1 protein levels in the hippocampal CA1 region, accompanied by restoration of both ERK and CREB phosphorylation and CaMKII autophosphorylation. Consistent with the restored CaMKII and ERK phosphorylation, an electrophysiological study showed that the impaired hippocampal long-term potentiation (LTP) observed in the 5-min ischemic mice was significantly improved by the nobiletin treatment. These findings suggest that the activation of CaMKII and ERK signaling in part mediates improvement of ischemia-induced learning and memory deficits by nobiletin.

  19. Hypoxia inducible factor stabilization improves defective ischemia-induced angiogenesis in a rodent model of chronic kidney disease.

    PubMed

    Schellinger, Isabel N; Cordasic, Nada; Panesar, Julian; Buchholz, Björn; Jacobi, Johannes; Hartner, Andrea; Klanke, Bernd; Jakubiczka-Smorag, Joanna; Burzlaff, Nicolai; Heinze, Eva; Warnecke, Christina; Raaz, Uwe; Willam, Carsten; Tsao, Philip S; Eckardt, Kai-Uwe; Amann, Kerstin; Hilgers, Karl F

    2017-03-01

    Chronic kidney disease (CKD) is associated with increased risk and worse prognosis of cardiovascular disease, including peripheral artery disease. An impaired angiogenic response to ischemia may contribute to poor outcomes of peripheral artery disease in patients with CKD. Hypoxia inducible factors (HIF) are master regulators of angiogenesis and therefore represent a promising target for therapeutic intervention. To test this we induced hind-limb ischemia in rats with CKD caused by 5/6 nephrectomy and administered two different treatments known to stabilize HIF protein in vivo: carbon monoxide and a pharmacological inhibitor of prolyl hydroxylation 2-(1-chloro-4- hydroxyisoquinoline-3-carboxamido) acetate (ICA). Expression levels of pro-angiogenic HIF target genes (Vegf, Vegf-r1, Vegf-r2, Ho-1) were measured by qRT-PCR. Capillary density was measured by CD31 immunofluorescence staining and HIF expression was evaluated by immunohistochemistry. Capillary density in ischemic skeletal muscle was significantly lower in CKD animals compared to sham controls. Rats with CKD showed significantly lower expression of HIF and all measured pro-angiogenic HIF target genes, including VEGF. Both HIF stabilizing treatments rescued HIF target gene expression in animals with CKD and led to significantly higher ischemia-induced capillary sprouting compared to untreated controls. ICA was effective regardless of whether it was administered before or after induction of ischemia and led to a HIF expression in skeletal muscle. Thus, impaired ischemia-induced angiogenesis in rats with CKD can be improved by HIF stabilization, even if started after onset of ischemia.

  20. Changes in HDL cholesterol and in the inflammatory markers of atherogenesis after an oral fat load in type-2 diabetic patients and normal individuals.

    PubMed

    Coutinho, Eponina R; Macedo, Geísa M; Campos, Florisbela S; Bandeira, Francisco A

    2008-06-01

    Type-2 diabetic patients exhibit postprandial hypertriglyceridemia, a risk factor for atherosclerosis. Several inflammatory markers are also risk factors for atherosclerosis, such as ultrasensitive C-reactive protein (CRP) and number of leukocytes. There is a relationship between the increase in triglycerides and that of leukocytes in the postprandial period. Our objective was to evaluate whether the lipid changes in the postprandial period are related to changes in the inflammatory markers of atherogenesis in type-2 diabetic patients. Lipids, ultrasensitive CRP, and leukocyte count were analyzed during fasting and after a meal containing 56 g of fat. There was a decrease in HDL-cholesterol at five hours in the control group and at three and five hours in the diabetic group, and an increase in triglycerides at both three and five hours in the two groups, the latter being more evident at five hours in the diabetic patients. The decrease in HDL-cholesterol in the diabetic patients was inversely proportional to waist circumference, waist hip ratio, and body mass index (BMI). The number of leukocytes showed an increase in both groups at both times, being more apparent at five hours. There were no differences in lipids or markers between the groups. The fall in postprandial HDL-cholesterol correlated with visceral obesity in the group with type-2 diabetes. Hypertriglyceridemia and lowered HDL-cholesterol in the postprandial period were accompanied by a rise in the number of leukocytes in both healthy and type-2 diabetic subjects.

  1. The intra-arterial injection of microglia protects hippocampal CA1 neurons against global ischemia-induced functional deficits in rats.

    PubMed

    Hayashi, Y; Tomimatsu, Y; Suzuki, H; Yamada, J; Wu, Z; Yao, H; Kagamiishi, Y; Tateishi, N; Sawada, M; Nakanishi, H

    2006-09-29

    In the present study, we have attempted to elucidate the effects of the intra-arterial injection of microglia on the global ischemia-induced functional and morphological deficits of hippocampal CA1 neurons. When PKH26-labeled immortalized microglial cells, GMIR1, were injected into the subclavian artery, these exogenous microglia were found to accumulate in the hippocampus at 24 h after ischemia. In hippocampal slices prepared from medium-injected rats subjected to ischemia 48 h earlier, synaptic dysfunctions including a significant reduction of synaptic responses and a marked reduction of long-term potentiation (LTP) of the CA3-CA1 Schaffer collateral synapses were observed. At this stage, however, neither significant neuronal degeneration nor gliosis was observed in the hippocampus. At 96 h after ischemia, there was a total loss of the synaptic activity and a marked neuronal death in the CA1 subfield. In contrast, the basal synaptic transmission and LTP of the CA3-CA1 synapses were well preserved after ischemia in the slices prepared from the microglia-injected animals. We also found the microglial-conditioned medium (MCM) to significantly increase the frequency of the spontaneous postsynaptic currents of CA1 neurons without affecting the amplitude, thus indicating that MCM increased the provability of the neurotransmitter release. The protective effect of the intra-arterial injected microglia against the ischemia-induced neuronal degeneration in the hippocampus was substantiated by immunohistochemical and immunoblot analyses. Furthermore, the arterial-injected microglia prevented the ischemia-induced decline of the brain-derived neurotrophic factor (BDNF) levels in CA1 neurons. These observations strongly suggest that the arterial-injection of microglia protected CA1 neurons against the ischemia-induced neuronal degeneration. The restoration of the ischemia-induced synaptic deficits and the resultant reduction of the BDNF levels in CA1 neurons, possibly by the

  2. Effects of rosuvastatin and pitavastatin on ischemia-induced myocardial stunning in dogs.

    PubMed

    Satoh, Kumi; Takaguri, Akira; Itagaki, Mai; Kano, Seiichiro; Ichihara, Kazuo

    2008-04-01

    Incomplete recovery of myocardial contraction after reperfusion following brief ischemia is called the "stunning phenomenon" in an animal experiment. A hydrophilic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor (statin) does not affect this phenomenon, but lipophilic statins further reduce the contraction during reperfusion. The effects of novel hydrophilic rosuvastatin and lipophilic pitavastatin on myocardial stunning in dogs were examined. In a preliminary experiment in vitro, pitavastatin reduced L6 cell viability at 10(-6) M and higher, whereas rosuvastatin and pravastatin up to 10(-5) M did not show such effects. An empty capsule or a capsule filled with rosuvastatin (2 mg/kg per day) or pitavastatin (0.4 mg/kg per day) was orally administered to dogs. After 3 weeks, both statins lowered the serum cholesterol level to the same extent. Under pentobarbital anesthesia, dogs were subjected to 15-min ischemia followed by 120-min reperfusion. Ischemia arrested the myocardial contraction in the ischemic area, and reperfusion recovered it but incompletely, showing the stunning phenomenon. Rosuvastatin did not modify the stunning phenomenon, while pitavastatin further deteriorated the myocardial contraction during reperfusion.

  3. LDL Cholesterol Test

    MedlinePlus

    ... Lipoprotein Cholesterol Related tests: Cholesterol ; HDL Cholesterol ; Triglycerides ; Lipid Profile ; Direct LDL Cholesterol ; Cardiac Risk Assessment ; Lp(a) ; ... LDL-C) is used as part of a lipid profile to predict an individual's risk of developing heart ...

  4. Cholesterol IQ Quiz

    MedlinePlus

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Cholesterol IQ Quiz Updated:Jul 5,2017 Begin the quiz Cholesterol • Home • About Cholesterol Introduction Atherosclerosis What Your Cholesterol ...

  5. Cholesterol and Your Child

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Cholesterol and Your Child KidsHealth > For Parents > Cholesterol and ... child's risk of developing heart disease later. About Cholesterol Cholesterol is a waxy substance produced by the ...

  6. Women and Cholesterol

    MedlinePlus

    ... Disease Venous Thromboembolism Aortic Aneurysm More Women and Cholesterol Updated:Apr 1,2016 The female sex hormone ... 2014. Related Sites Nutrition Center My Life Check Cholesterol • Home • About Cholesterol • Why Cholesterol Matters • Understand Your ...

  7. Common Misconceptions about Cholesterol

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More Common Misconceptions about Cholesterol Updated:Apr 3,2017 Cholesterol can be both ... misconceptions about cholesterol. Click on each misconception about cholesterol to see the truth: My choices about diet ...

  8. Lifestyle Changes and Cholesterol

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More Lifestyle Changes and Cholesterol Updated:Sep 26,2016 As part of a ... to the Terms and Conditions and Privacy Policy Cholesterol • Home • About Cholesterol • Why Cholesterol Matters • Understand Your ...

  9. Combined training (strength plus aerobic) potentiates a reduction in body fat but only functional training reduced low-density lipoprotein cholesterol in postmenopausal women with a similar training load

    PubMed Central

    Rossi, Fabrício Eduardo; Fortaleza, Ana Claudia S.; Neves, Lucas M.; Diniz, Tiego A.; de Castro, Marcela R.; Buonani, Camila; Mota, Jorge; Freitas, Ismael F.

    2017-01-01

    The aim of this study was to compare the effects of combined (CT; strength plus aerobic) and functional training (FT) on the body composition and metabolic profile with a similar training load in postmenopausal women. The participants were divided into three groups: CT (n=20), FT (n=17), and control group (CG, n=15). The trunk FM, fat mass (FM), percentage of FM (FM%), and fat-free mass were estimated by dual-energy X-ray absorptiometry. The metabolic profile, glucose, triacylglycerol, total cholesterol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol (LDL-c) were assessed. There were main effects of time in trunk fat, FM, and FM% (P<0.05). There were statistically significant interaction for FM (P=0.015), FM% (P=0.017) with lower values for CT group. For LDL-c, there was significant interaction (P=0.002) with greater values for FT group in relation to CG and CT. Furthermore, when performed the post hoc test on the “mean absolute differences” (Δ), it can observed statistically significant difference between FT, CT, and CG (−13.0±16.5 mg/dL vs. 4.8±18.4 mg/dL vs. 9.2±18.8 mg/dL, P<0.05). In conclusion, when training loads are equivalent CT potentiated a reduction in FM and FM%, however, only FT reduced LDL-c in postmenopausal women. PMID:28702444

  10. Critical Roles of Reactive Oxygen Species in Age-Related Impairment in Ischemia-Induced Neovascularization by Regulating Stem and Progenitor Cell Function

    PubMed Central

    Lam, Yuen Ting

    2016-01-01

    Reactive oxygen species (ROS) regulate bone marrow microenvironment for stem and progenitor cells functions including self-renewal, differentiation, and cell senescence. In response to ischemia, ROS also play a critical role in mediating the mobilization of endothelial progenitor cells (EPCs) from the bone marrow to the sites of ischemic injury, which contributes to postnatal neovascularization. Aging is an unavoidable biological deteriorative process with a progressive decline in physiological functions. It is associated with increased oxidative stress and impaired ischemia-induced neovascularization. This review discusses the roles of ROS in regulating stem and progenitor cell function, highlighting the impact of unbalanced ROS levels on EPC dysfunction and the association with age-related impairment in ischemia-induced neovascularization. Furthermore, it discusses strategies that modulate the oxidative levels of stem and progenitor cells to enhance the therapeutic potential for elderly patients with cardiovascular disease. PMID:26697140

  11. An enzyme-entrapped agarose gel for visualization of ischemia-induced L-glutamate fluxes in hippocampal slices in a flow system.

    PubMed

    Tanaka, Kazuhisa; Shoji, Atushi; Sugawara, Masao

    2015-01-01

    An agarose gel slip containing L-glutamate oxidase (GluOx), horseradish peroxidase (HRP) and a dye DA-64 is proposed as a tool for visualizing ischemia-induced L-glutamate release in hippocampal slices in a flow system. The agarose slip with a detection limit of 6.0 ± 0.8 μmol L(-1) for L-glutamate enabled us to visualize L-glutamate fluxes in a flow system. The leak of a dye from the agarose gel was negligible and a diffusion blur due to spreading of Bindshedler's Green (BG) within the gel was suppressed. Monitoring the time-dependent change of ischemia-induced L-glutamate fluxes at neuronal regions CA1, DG and CA3 of hippocampal slices is demonstrated.

  12. PKCβ: Expanding role in hepatic adaptation of cholesterol homeostasis to dietary fat/cholesterol.

    PubMed

    Mehta, Devina; Mehta, Kamal D

    2017-03-01

    Cholesterol homeostasis relies on an intricate network of cellular processes whose deregulation in response to Western type high-fat/cholesterol diets can lead to several life-threatening pathologies. Significant advances have been made in resolving the molecular identity and regulatory function of transcription factors sensitive to fat, cholesterol, or bile acids, but whether body senses the presence of both fat and cholesterol simultaneously is not known. Assessing the impact of a high-fat/cholesterol load, rather than an individual component alone, on cholesterol homeostasis is more physiologically relevant because Western diets deliver both fat and cholesterol at the same time. Moreover, dietary fat and dietary cholesterol are reported to act synergistically to impair liver cholesterol homeostasis. A key insight into the role of protein kinase C-β (PKCβ) in hepatic adaptation to high-fat/cholesterol diets was gained recently through the use of knockout mice. The emerging evidence indicates that PKCβ is an important regulator of cholesterol homeostasis that ensures normal adaptation to high-fat/cholesterol intake. Consistent with this function, high-fat/cholesterol diets induce PKCβ expression and signaling in the intestine and liver, while systemic PKCβ deficiency promotes accumulation of cholesterol in the liver and bile. PKCβ disruption results in profound dysregulation of hepatic cholesterol and bile homeostasis and imparts sensitivity to cholesterol gallstone formation. The available results support involvement of a two-pronged mechanism by which intestine and liver PKCβ signaling converge on liver ERK1/2 to dictate diet-induced cholesterol and bile acid homeostasis. Collectively, PKCβ is an integrator of dietary fat/cholesterol signal and mediates changes to cholesterol homeostasis.

  13. Paraplegia increased cardiac NGF content, sympathetic tonus, and the susceptibility to ischemia-induced ventricular tachycardia in conscious rats

    PubMed Central

    Lujan, Heidi L.; Chen, Ying; DiCarlo, Stephen E.

    2009-01-01

    Midthoracic spinal cord injury is associated with ventricular arrhythmias that are mediated, in part, by enhanced cardiac sympathetic activity. Furthermore, it is well known that sympathetic neurons have a lifelong requirement for nerve growth factor (NGF). NGF is a neurotrophin that supports the survival and differentiation of sympathetic neurons and enhances target innervation. Therefore, we tested the hypothesis that paraplegia is associated with an increased cardiac NGF content, sympathetic tonus, and susceptibility to ischemia-induced ventricular tachyarrhythmias. Intact and paraplegic (6–9 wk posttransection, T5 spinal cord transection) rats were instrumented with a radiotelemetry device for recording arterial pressure, temperature, and ECG, and a snare was placed around the left main coronary artery. Following recovery, the susceptibility to ventricular arrhythmias (coronary artery occlusion) was determined in intact and paraplegic rats. In additional groups of matched intact and paraplegic rats, cardiac nerve growth factor content (ELISA) and cardiac sympathetic tonus were determined. Paraplegia, compared with intact, increased cardiac nerve growth factor content (2,146 ± 286 vs. 180 ± 36 pg/ml, P < 0.05) and cardiac sympathetic tonus (154 ± 4 vs. 68 ± 4 beats/min, P < 0.05) and decreased the ventricular arrhythmia threshold (3.6 ± 0.2 vs. 4.9 ± 0.2 min, P < 0.05). Thus altered autonomic behavior increases the susceptibility to ventricular arrhythmias in paraplegic rats. PMID:19286942

  14. Immediate and delayed treatments with curcumin prevents forebrain ischemia-induced neuronal damage and oxidative insult in the rat hippocampus.

    PubMed

    Al-Omar, Fadhel A; Nagi, Mahmoud N; Abdulgadir, Mustafa M; Al Joni, Khalda S; Al-Majed, Abdulhakeem A

    2006-05-01

    Oxidative stress is believed to contribute to neurodegeneration following ischemic injury. The present study was undertaken to evaluate the possible antioxidant neuroprotective effect of curcumin (Cur) on neuronal death of hippocampal CA1 neurons following transient forebrain ischemia in rat. Treatment of Cur (200 mg/kg/day, i.p.) at three different times (immediately, 3 h and 24 h after ischemia) significantly (P<0.01) reduced neuronal damage 7 days after ischemia. Also, treatment of ischemic rats with Cur decreased the elevated levels of MDA and increased GSH contents, catalase and SOD activities to normal levels. In the in vitro, Cur was as potent as antioxidant (IC(50) = 1 microM) as butylated hydroxytoluene. The present study demonstrates that curcumin treatment attenuates forebrain ischemia-induced neuronal injury and oxidative stress in hippocampal tissue. Thus treatment with curcumin immediately or even delayed until 24 h may have the potential to be used as a protective agent in forebrain ischemic insult in human.

  15. Ginkgo biloba Prevents Transient Global Ischemia-Induced Delayed Hippocampal Neuronal Death Through Antioxidant and Anti-inflammatory Mechanism

    PubMed Central

    Tulsulkar, Jatin; Shah, Zahoor A.

    2012-01-01

    We have previously reported neuroprotective properties of Ginkgo biloba/EGb 761® (EGb 761) in transient and permanent mouse models of brain ischemia. In a quest to extend our studies on EGB 761 and its constituents further, we used a model of transient global ischemia induced delayed hippocampal neuronal death and inflammation. Mice pretreated with different test drugs for 7 days were subjected to eight-minute bilateral common carotid artery occlusion (tBCCAO) at day 8. After 7 days of reperfusion, mice brains were dissected out for TUNEL assay and immunohistochemistry. In-situ detection of fragmented DNA (TUNEL staining) showed that out of all test drugs, only EGb 761 (13.6% ± 3.2) pretreatment protected neurons in the hippocampus against global ischemia (vs. vehicle, 85.1% ± 9.9; p < 0.05). Immunofluorescence-based studies demonstrated that pretreatment with EGb 761 upregulated the expression levels of heme oxygenase 1 (HO1), nuclear factor erythroid 2-related factor 2 (Nrf2), and vascular endothelial growth factor (VEGF) as compared to the vehicle group. In addition, increased number of activated astrocytes and microglia in the vehicle group was observed to be significantly lower in the EGb 761 pretreated group. Together, these results suggest that EGb 761 is a multifunctional neuroprotective agent, and the protection is in part associated with activation of the HO1/Nrf2 pathway, upregulation of VEGF and downregulation of inflammatory mediators such as astrocytes and microglia. PMID:23228346

  16. Anthocyanins block ischemia-induced apoptosis in the perfused heart and support mitochondrial respiration potentially by reducing cytosolic cytochrome c.

    PubMed

    Skemiene, Kristina; Rakauskaite, Gintare; Trumbeckaite, Sonata; Liobikas, Julius; Brown, Guy C; Borutaite, Vilmante

    2013-01-01

    Anthocynanins, found in fruits and vegetables, have a variety of protective properties, which have generally been attributed to their antioxidant capacity. However, antioxidants are generally strong reductants, and some reductants have been found to block apoptosis by reducing cytosolic cytochrome c, which prevents caspase activation. We tested the ability of various anthocyanins: to reduce cytochrome c, to support cytochrome c-induced mitochondrial respiration and to inhibit apoptosis induced by heart ischemia. Anthocyanins such as delphinidin-3-glucoside (Dp3G) and cyanidin-3-glucoside (Cy3G) were able to reduce cytochrome c directly and rapidly, whereas pelargonidin-3-glucoside (Pg3G), malvinidin-3-glucoside (Mv3G) and peonidin-3-glucoside (Pn3G) had relatively low cytochrome c reducing activities. Dp3G and Cy3G but not Pg3G supported mitochondrial state 4 respiration in the presence of exogenous cytochrome c. Pre-perfusion of hearts with 20 μM Cy3G but not Pg3G prevented ischemia-induced caspase activation. This suggests that the ability of anthocyanins to block caspase activation may be due to their ability to reduce cytosolic cytochrome c. This article is part of a Directed Issue entitled: Bioenergetic dysfunction, adaptation and therapy. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Acute estradiol protects CA1 neurons from ischemia-induced apoptotic cell death via the PI3K/Akt pathway

    PubMed Central

    Jover-Mengual, Teresa; Miyawaki, Takahiro; Latuszek, Adrianna; Alborch, Enrique; Zukin, R. Suzanne; Etgen, Anne M.

    2010-01-01

    Global ischemia arising during cardiac arrest or cardiac surgery causes highly selective, delayed death of hippocampal CA1 neurons. Exogenous estradiol ameliorates global ischemia-induced neuronal death and cognitive impairment in male and female rodents. However, the molecular mechanisms by which a single acute injection of estradiol administered after the ischemic event intervenes in global ischemia-induced apoptotic cell death are unclear. Here we show that acute estradiol acts via the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling cascade to protect CA1 neurons in ovariectomized female rats. We demonstrate that global ischemia promotes early activation of glycogen synthase kinase-3β (GSK3β) and forkhead transcription factor of the O class (FOXO)3A, known Akt targets that are related to cell survival, and activation of caspase-3. Estradiol prevents ischemia-induced dephosphorylation and activation of GSK3β and FOXO3A, and the caspase death cascade. These findings support a model whereby estradiol acts by activation of PI3K/Akt signaling to promote neuronal survival in the face of global ischemia. PMID:20114038

  18. Sulforaphane Improves Ischemia-Induced Detrusor Overactivity by Downregulating the Enhancement of Associated Endoplasmic Reticulum Stress, Autophagy, and Apoptosis in Rat Bladder

    PubMed Central

    Tai, Huai-Ching; Chung, Shiu-Dong; Chien, Chiang-Ting; Yu, Hong-Jeng

    2016-01-01

    Atherosclerosis-associated pelvic ischemia has been reported to be a risk factor for bladder dysfunction and subsequent lower urinary tract symptoms (LUTS) in the elderly population. However, the molecular mechanisms of this association remain unclear. We hypothesized that stress-induced cellular responses might play a role in the pathogenesis of ischemia-induced bladder dysfunction. In the present study, the animal model of bladder ischemia was induced by bilateral partial arterial occlusion (BPAO) in rats. We found that BPAO significantly induced the presence of detrusor overactivity (DO) and upregulated the expression of several molecular reactions, including biomarkers in endoplasmic reticulum stress (78 kDa glucose-regulated protein, GRP78 and C/EBP-homologous protein, CHOP), autophagy (Beclin-1, p62 and LC3 II) and apoptosis (caspase 3). BPAO also disturbed the Kelch-like ECH-associated protein 1–nuclear factor erythroid-2-related factor 2 (Keap1–Nrf2) pathways. These responses might collectively alter muscarinic and purinergic signaling and contribute to the presence of DO in the ischemic bladder. Therapeutically, treatment with neither a muscarinic nor purinergic receptor antagonist restored bladder function. Interestingly, sulforaphane effectively attenuated ischemia-enhanced endoplasmic reticulum stress, autophagy and apoptosis in the bladder, subsequently ameliorated ischemia-induced bladder dysfunction and might emerge as a novel strategy to protect the bladder against ischemia-induced oxidative damage. PMID:27824068

  19. Spreading depolarization remarkably exacerbates ischemia-induced tissue acidosis in the young and aged rat brain.

    PubMed

    Menyhárt, Ákos; Zölei-Szénási, Dániel; Puskás, Tamás; Makra, Péter; Orsolya, M Tóth; Szepes, Borbála É; Tóth, Réka; Ivánkovits-Kiss, Orsolya; Obrenovitch, Tihomir P; Bari, Ferenc; Farkas, Eszter

    2017-04-25

    Spreading depolarizations (SDs) occur spontaneously in the cerebral cortex of subarachnoid hemorrhage, stroke or traumatic brain injury patients. Accumulating evidence prove that SDs exacerbate focal ischemic injury by converting zones of the viable but non-functional ischemic penumbra to the core region beyond rescue. Yet the SD-related mechanisms to mediate neurodegeneration remain poorly understood. Here we show in the cerebral cortex of isoflurane-anesthetized, young and old laboratory rats, that SDs propagating under ischemic penumbra-like conditions decrease intra and- extracellular tissue pH transiently to levels, which have been recognized to cause tissue damage. Further, tissue pH after the passage of each spontaneous SD event remains acidic for over 10 minutes. Finally, the recovery from SD-related tissue acidosis is hampered further by age. We propose that accumulating acid load is an effective mechanism for SD to cause delayed cell death in the ischemic nervous tissue, particularly in the aged brain.

  20. Cholesterol efflux analyses using stable isotopes and mass spectrometry

    PubMed Central

    Brown, Robert J.; Shao, Fei; Baldán, Ángel; Albert, Carolyn J.; Ford, David A.

    2012-01-01

    Cholesterol efflux from macrophages and the vascular wall is the initial step of the cardiovascular protective reverse cholesterol transport process. This study demonstrates a mass spectrometry based assay to measure the cellular and media content of [d7]-cholesterol and unlabeled cholesterol that can be used to measure cholesterol efflux from cell lines. Using a triple quadrupole ESI-MS instrument in direct infusion mode, product ion scanning for m/z 83, neutral loss (NL) 375.5 scanning and NL 368.5 scanning were used to detect cholesterol (as an acetylated derivative), [d7]-cholesteryl ester (CE) and unlabeled CE, respectively. The same mass of [d7]-cholesterol was substituted for [3H]-cholesterol under standard efflux assay conditions. At the end of [d7]-cholesterol loading, the intracellular mass of [d7]-cholesterol was 2-fold greater than unlabeled cholesterol, and the intracellular [d7]-CE profile is similar to unlabeled CE. Efflux of cholesterol to apolipoprotein A-I and high-density lipoproteins was similar when comparing efflux of either [d7]-cholesterol or [3H]-cholesterol as measured by following efflux of the tracers only. This technique also can be used to assess the efflux of unlabeled cholesterol to acceptors in media that are initially cholesterol-free (e.g., apolipoprotein A-I). Taken together, this mass spectrometry based assay provides new molecular detail to assess cholesterol efflux. PMID:23072980

  1. What Is Cholesterol?

    MedlinePlus

    ... Can I Help Someone Who's Being Bullied? Volunteering Cholesterol KidsHealth > For Teens > Cholesterol Print A A A ... High Cholesterol? en español ¿Qué es el colesterol? Cholesterol Is a Fat in the Blood Cholesterol (kuh- ...

  2. What Is Cholesterol?

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Cholesterol KidsHealth > For Teens > Cholesterol A A A What's ... High Cholesterol? en español ¿Qué es el colesterol? Cholesterol Is a Fat in the Blood Cholesterol (kuh- ...

  3. Cellular Cholesterol Regulates Ubiquitination and Degradation of the Cholesterol Export Proteins ABCA1 and ABCG1*

    PubMed Central

    Hsieh, Victar; Kim, Mi-Jurng; Gelissen, Ingrid C.; Brown, Andrew J.; Sandoval, Cecilia; Hallab, Jeannette C.; Kockx, Maaike; Traini, Mathew; Jessup, Wendy; Kritharides, Leonard

    2014-01-01

    The objective of this study was to examine the influence of cholesterol in post-translational control of ABCA1 and ABCG1 protein expression. Using CHO cell lines stably expressing human ABCA1 or ABCG1, we observed that the abundance of these proteins is increased by cell cholesterol loading. The response to increased cholesterol is rapid, is independent of transcription, and appears to be specific for these membrane proteins. The effect is mediated through cholesterol-dependent inhibition of transporter protein degradation. Cell cholesterol loading similarly regulates degradation of endogenously expressed ABCA1 and ABCG1 in human THP-1 macrophages. Turnover of ABCA1 and ABCG1 is strongly inhibited by proteasomal inhibitors and is unresponsive to inhibitors of lysosomal proteolysis. Furthermore, cell cholesterol loading inhibits ubiquitination of ABCA1 and ABCG1. Our findings provide evidence for a rapid, cholesterol-dependent, post-translational control of ABCA1 and ABCG1 protein levels, mediated through a specific and sterol-sensitive mechanism for suppression of transporter protein ubiquitination, which in turn decreases proteasomal degradation. This provides a mechanism for acute fine-tuning of cholesterol transporter activity in response to fluctuations in cell cholesterol levels, in addition to the longer term cholesterol-dependent transcriptional regulation of these genes. PMID:24500716

  4. Liquid fructose in Western-diet-fed mice impairs liver insulin signaling and causes cholesterol and triglyceride loading without changing calorie intake and body weight.

    PubMed

    Baena, Miguel; Sangüesa, Gemma; Hutter, Natalia; Beltrán, José María; Sánchez, Rosa María; Roglans, Núria; Alegret, Marta; Laguna, Juan Carlos

    2017-02-01

    Liquid fructose associates with prevalence of type 2 diabetes mellitus and obesity. Intervention studies suggest that metabolically unfit individuals are more responsive than healthy individuals to liquid fructose. We determined whether mice consuming an obesogenic Western diet were more responsive than chow-fed mice to the alterations induced by liquid fructose supplementation (LFS). C57BL/6N mice were fed chow or Western diet±ad libitum 15% fructose solution for 12 weeks. Food and liquid intake and body weight were monitored. Plasma analytes and liver lipids, histology and the expression of genes related to lipid handling, endoplasmic reticulum stress, inflammation and insulin signaling were analyzed. Western diet increased energy intake, visceral adipose tissue (vWAT), body weight, plasma and liver triglycerides and cholesterol, and inflammatory markers in vWAT vs. chow-fed mice. LFS did not change energy intake, vWAT or body weight. LFS significantly increased plasma and liver triglycerides and cholesterol levels only in Western-diet-fed mice. These changes associated with a potentiation of the increased liver expression of PPARγ and CD36 that was observed in Western-fed mice and related to the increased liver mTOR phosphorylation induced by LFS. Furthermore, LFS in Western-diet-fed mice induced the largest reduction in liver IRS2 protein and a significant decrease in whole-body insulin sensitivity. LFS in mice, in a background of an unhealthy diet that already induces fatty liver visceral fat accretion and obesity, increases liver lipid burden, hinders hepatic insulin signaling and diminishes whole-body insulin sensitivity without changing energy intake. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Resveratrol ameliorates hypoxia/ischemia-induced brain injury in the neonatal rat via the miR-96/Bax axis.

    PubMed

    Bian, Hongen; Shan, Haijun; Chen, Tuanying

    2017-07-18

    This study was aimed to investigate the mechanism of resveratrol on amelioration of hypoxia/ischemia (H/I)-induced brain injury. The RT-PCR and western blot were used to detect the mRNA and protein expressions, respectively. The PC12 cell induced by OGD/R was as in vitro H/I brain injury model. The luciferase reporter assay was used to prove the relationship between Bax and miR-96, and the cell apoptosis was detected by MTT assay. The loss of MBP+ area in neonatal rats analyzed by immunohistochemistry was to evaluate the extent of brain injury. The miR-96 expression was decreased in the hippocampus and cerebral cortex of neonatal rats with H/I brain injury and the oxygenglucose deprivation/re-oxygenation (OGD/R)-induced PC12 cell, while Bax expression was opposite. And then the H/I rats and OGD/R-induced PC12 cell were treated with resveratrol (RSV); the results showed that the RSV could reverse the miR-96 and Bax expressions. Next, the luciferase reporter assay proved that Bax was a target of miR-96. We used the miR-96 inhibitor to suppress miR-96 expression in OGD/R-induced PC12 cell, and found that RSV regulated Bax expression and prevented OGD/R-induced PC12 cell apoptosis via miR-96. In addition, the immunohistochemistry was used to analyze the loss of MBP+ area in neonatal rats, and the result showed that the RSV significantly reduced the brain damage, increased miR-96 expression, and decreased Bax expression, while inhibition of miR-96 aggravated the brain damage and reversed the effect of RSV. Resveratrol ameliorates hypoxia/ischemia-induced brain injury in neonatal rat via the miR-96/ Bax axis.

  6. Insights into the epigenetic mechanisms involving histone lysine methylation and demethylation in ischemia induced damage and repair has therapeutic implication.

    PubMed

    Chakravarty, Sumana; Jhelum, Priya; Bhat, Unis Ahmad; Rajan, Wenson D; Maitra, Swati; Pathak, Salil S; Patel, Anant B; Kumar, Arvind

    2017-01-01

    Cerebral ischemic stroke is one of the leading causes of death and disability worldwide. Therapeutic interventions to minimize ischemia-induced neural damage are limited due to poor understanding of molecular mechanisms mediating complex pathophysiology in stroke. Recently, epigenetic mechanisms mostly histone lysine (K) acetylation and deacetylation have been implicated in ischemic brain damage and have expanded the dimensions of potential therapeutic intervention to the systemic/local administration of histone deacetylase inhibitors. However, the role of other epigenetic mechanisms such as histone lysine methylation and demethylation in stroke-induced damage and subsequent recovery process is elusive. Here, we established an Internal Carotid Artery Occlusion (ICAO) model in CD1 mouse that resulted in mild to moderate level of ischemic damage to the striatum, as suggested by magnetic resonance imaging (MRI), TUNEL and histopathological staining along with an evaluation of neurological deficit score (NDS), grip strength and rotarod performance. The molecular investigations show dysregulation of a number of histone lysine methylases (KMTs) and few of histone lysine demethylases (KDMs) post-ICAO with significant global attenuation in the transcriptionally repressive epigenetic mark H3K9me2 in the striatum. Administration of Dimethyloxalylglycine (DMOG), an inhibitor of KDM4 or JMJD2 class of histone lysine demethylases, significantly ameliorated stroke-induced NDS by restoring perturbed H3K9me2 levels in the ischemia-affected striatum. Overall, these results highlight the novel role of epigenetic regulatory mechanisms controlling the epigenetic mark H3K9me2 in mediating the stroke-induced striatal damage and subsequent repair following mild to moderate cerebral ischemia.

  7. Casein Kinase 1 Suppresses Activation of REST in Insulted Hippocampal Neurons and Halts Ischemia-Induced Neuronal Death

    PubMed Central

    Kaneko, Naoki; Hwang, Jee-Yeon; Gertner, Michael; Pontarelli, Fabrizio

    2014-01-01

    Repressor Element-1 (RE1) Silencing Transcription Factor/Neuron-Restrictive Silencer Factor (REST/NRSF) is a gene-silencing factor that is widely expressed during embryogenesis and plays a strategic role in neuronal differentiation. Recent studies indicate that REST can be activated in differentiated neurons during a critical window of time in postnatal development and in adult neurons in response to neuronal insults such as seizures and ischemia. However, the mechanism by which REST is regulated in neurons is as yet unknown. Here, we show that REST is controlled at the level of protein stability via β-TrCP-dependent, ubiquitin-based proteasomal degradation in differentiated neurons under physiological conditions and identify Casein Kinase 1 (CK1) as an upstream effector that bidirectionally regulates REST cellular abundance. CK1 associates with and phosphorylates REST at two neighboring, but distinct, motifs within the C terminus of REST critical for binding of β-TrCP and targeting of REST for proteasomal degradation. We further show that global ischemia in rats in vivo triggers a decrease in CK1 and an increase in REST in selectively vulnerable hippocampal CA1 neurons. Administration of the CK1 activator pyrvinium pamoate by in vivo injection immediately after ischemia restores CK1 activity, suppresses REST expression, and rescues neurons destined to die. Our results identify a novel and previously unappreciated role for CK1 as a brake on REST stability and abundance in adult neurons and reveal that loss of CK1 is causally related to ischemia-induced neuronal death. These findings point to CK1 as a potential therapeutic target for the amelioration of hippocampal injury and cognitive deficits associated with global ischemia. PMID:24760862

  8. Placental ischemia-induced increases in brain water content and cerebrovascular permeability: role of TNF-α

    PubMed Central

    Warrington, Junie P.; Drummond, Heather A.; Granger, Joey P.

    2015-01-01

    Cerebrovascular complications and increased risk of encephalopathies are characteristic of preeclampsia and contribute to 40% of preeclampsia/eclampsia-related deaths. Circulating tumor necrosis factor-α (TNF-α) is elevated in preeclamptic women, and infusion of TNF-α into pregnant rats mimics characteristics of preeclampsia. While this suggests that TNF-α has a mechanistic role to promote preeclampsia, the impact of TNF-α on the cerebral vasculature during pregnancy remains unclear. We tested the hypothesis that TNF-α contributes to cerebrovascular abnormalities during placental ischemia by first infusing TNF-α in pregnant rats (200 ng/day ip, from gestational day 14 to 19) at levels to mimic those reported in preeclamptic women. TNF-α increased mean arterial pressure (MAP, P < 0.05) and brain water content in the anterior cerebrum (P < 0.05); however, TNF-α infusion had no effect on blood-brain barrier (BBB) permeability in the anterior cerebrum or posterior cerebrum. We then assessed the role of endogenous TNF-α in mediating these abnormalities in a model of placental ischemia induced by reducing uterine perfusion pressure followed by treatment with the soluble TNF-α receptor (etanercept, 0.8 mg/kg sc) on gestational day 18. Etanercept reduced placental ischemia-mediated increases in MAP, anterior brain water content (P < 0.05), and BBB permeability (202 ± 44% in placental ischemic rats to 101 ± 28% of normal pregnant rats). Our results indicate that TNF-α mechanistically contributes to cerebral edema by increasing BBB permeability and is an underlying factor in the development of cerebrovascular abnormalities associated with preeclampsia complicated by placental ischemia. PMID:26400187

  9. HDL Cholesterol Test

    MedlinePlus

    ... Lipoprotein Cholesterol Related tests: Cholesterol ; LDL Cholesterol ; Triglycerides ; Lipid Profile ; Cardiac Risk Assessment ; Lp-PLA2 All content on ... HDL-C) is used as part of a lipid profile to screen for unhealthy levels of lipids and ...

  10. Causes of High Cholesterol

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More Causes of High Cholesterol Updated:Jul 5,2017 If you have high ... and procedures related to heart disease and stroke. Cholesterol • Home • About Cholesterol • HDL, LDL, and Triglycerides • Causes ...

  11. Common Misconceptions about Cholesterol

    MedlinePlus

    ... Do My Cholesterol Levels Mean? | Spanish Your Cholesterol Score Explained What Are High Blood Cholesterol and Triglycerides? ... Pressure? 7 All About Heart Rate (Pulse) 8 Warning Signs of a Heart Attack 9 Tachycardia | Fast ...

  12. Cell Cholesterol Homeostasis: Mediation by Active Cholesterol

    PubMed Central

    Steck, Theodore L.; Lange, Yvonne

    2010-01-01

    Recent evidence suggests that the major pathways mediating cell cholesterol homeostasis respond to a common signal: active membrane cholesterol. Active cholesterol is that fraction which exceeds the complexing capacity of the polar bilayer lipids. Increments in plasma membrane cholesterol exceeding this threshold have an elevated chemical activity (escape tendency) and redistribute via diverse transport proteins to both circulating plasma lipoproteins and intracellular organelles. Active cholesterol prompts several feedback responses thereby. It is the substrate for its own esterification and for the synthesis of regulatory side-chain oxysterols. It also stimulates manifold pathways that down-regulate the biosynthesis, curtail the ingestion and increase the export of cholesterol. Thus, the abundance of cholesterol is tightly coupled to that of its polar lipid partners through active cholesterol. PMID:20843692

  13. The Structural Basis of Cholesterol Activity in Membranes

    SciTech Connect

    Olsen, Brett N.; Bielska, Agata; Lee, Tiffany; Daily, Michael D.; Covey, Douglas F.; Schlesinger, Paul H.; Baker, Nathan A.; Ory, Daniel S.

    2013-10-15

    Although the majority of free cellular cholesterol is present in the plasma membrane, cholesterol homeostasis is principally regulated through sterol-sensing proteins that reside in the cholesterol-poor endoplasmic reticulum (ER). In response to acute cholesterol loading or depletion, there is rapid equilibration between the ER and plasma membrane cholesterol pools, suggesting a biophysical model in which the availability of plasma membrane cholesterol for trafficking to internal membranes modulates ER membrane behavior. Previous studies have predominantly examined cholesterol availability in terms of binding to extramembrane acceptors, but have provided limited insight into the structural changes underlying cholesterol activation. In this study, we use both molecular dynamics simulations and experimental membrane systems to examine the behavior of cholesterol in membrane bilayers. We find that cholesterol depth within the bilayer provides a reasonable structural metric for cholesterol availability and that this is correlated with cholesterol-acceptor binding. Further, the distribution of cholesterol availability in our simulations is continuous rather than divided into distinct available and unavailable pools. This data provide support for a revised cholesterol activation model in which activation is driven not by saturation of membrane-cholesterol interactions but rather by bulk membrane remodeling that reduces membrane-cholesterol affinity.

  14. The Structural Basis of Cholesterol Accessibility in Membranes

    PubMed Central

    Olsen, Brett N.; Bielska, Agata A.; Lee, Tiffany; Daily, Michael D.; Covey, Douglas F.; Schlesinger, Paul H.; Baker, Nathan A.; Ory, Daniel S.

    2013-01-01

    Although the majority of free cellular cholesterol is present in the plasma membrane, cholesterol homeostasis is principally regulated through sterol-sensing proteins that reside in the cholesterol-poor endoplasmic reticulum (ER). In response to acute cholesterol loading or depletion, there is rapid equilibration between the ER and plasma membrane cholesterol pools, suggesting a biophysical model in which the availability of plasma membrane cholesterol for trafficking to internal membranes modulates ER membrane behavior. Previous studies have predominantly examined cholesterol availability in terms of binding to extramembrane acceptors, but have provided limited insight into the structural changes underlying cholesterol activation. In this study, we use both molecular dynamics simulations and experimental membrane systems to examine the behavior of cholesterol in membrane bilayers. We find that cholesterol depth within the bilayer provides a reasonable structural metric for cholesterol availability and that this is correlated with cholesterol-acceptor binding. Further, the distribution of cholesterol availability in our simulations is continuous rather than divided into distinct available and unavailable pools. This data provide support for a revised cholesterol activation model in which activation is driven not by saturation of membrane-cholesterol interactions but rather by bulk membrane remodeling that reduces membrane-cholesterol affinity. PMID:24138860

  15. Compared with Acyl-CoA:cholesterol O-acyltransferase (ACAT) 1 and lecithin:cholesterol acyltransferase, ACAT2 displays the greatest capacity to differentiate cholesterol from sitosterol.

    PubMed

    Temel, Ryan E; Gebre, Abraham K; Parks, John S; Rudel, Lawrence L

    2003-11-28

    The capacity of acyl-CoA:cholesterol O-acyltransferase (ACAT) 2 to differentiate cholesterol from the plant sterol, sitosterol, was compared with that of the sterol esterifying enzymes, ACAT1 and lecithin:cholesterol acyltransferase (LCAT). Cholesterol-loaded microsomes from transfected cells containing either ACAT1 or ACAT2 exhibited significantly more ACAT activity than their sitosterol-loaded counterparts. In sitosterol-loaded microsomes, both ACAT1 and ACAT2 were able to esterify sitosterol albeit with lower efficiencies than cholesterol. The mass ratios of cholesterol ester to sitosterol ester formed by ACAT1 and ACAT2 were 1.6 and 7.2, respectively. Compared with ACAT1, ACAT2 selectively esterified cholesterol even when sitosterol was loaded into the microsomes. To further characterize the difference in sterol specificity, ACAT1 and ACAT2 were compared in intact cells loaded with either cholesterol or sitosterol. Despite a lower level of ACAT activity, the ACAT1-expressing cells esterified 4-fold more sitosterol than the ACAT2 cells. The data showed that compared with ACAT1, ACAT2 displayed significantly greater selectively for cholesterol compared with sitosterol. The plasma cholesterol esterification enzyme lecithin:cholesterol acyltransferase was also compared. With recombinant high density lipoprotein particles, the esterification rate of cholesterol by LCAT was only 15% greater than for sitosterol. Thus, LCAT was able to efficiently esterify both cholesterol and sitosterol. In contrast, ACAT2 demonstrated a strong preference for cholesterol rather than sitosterol. This sterol selectivity by ACAT2 may reflect a role in the sorting of dietary sterols during their absorption by the intestine in vivo.

  16. Inhibitory Effects of Isoquinoline Alkaloid Berberine on Ischemia-Induced Apoptosis via Activation of Phosphoinositide 3-Kinase/Protein Kinase B Signaling Pathway

    PubMed Central

    Kim, Mia; Shin, Mal Soon; Lee, Jae Min; Cho, Han Sam; Kim, Chang Ju; Kim, Young Joon; Choi, Hey Ran

    2014-01-01

    Purpose Berberine is a type of isoquinoline alkaloid that has been used to treat various diseases. A neuroprotective effect of berberine against cerebral ischemia has been reported; however, the effects of berberine on apoptosis in relation to reactive astrogliosis and microglia activation under ischemic conditions have not yet been fully evaluated. In the present study, we investigated the effects of berberine on global ischemia-induced apoptosis, and focused on the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway in the hippocampus using gerbils. Methods Gerbils received berberine orally once a day for 14 consecutive days, starting one day after surgery. In this study, a step-down avoidance task was used to assess short-term memory. Furthermore, we employed the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay to evaluate DNA fragmentation, immunohistochemistry to investigate glial fibriallary acidic protein, CD11b, and caspase-3, and western blot to assess PI3K, Akt, Bax, Bcl-2, and cytochrome c. Results Our results revealed that berberine treatment alleviated ischemia-induced short-term memory impairment. Treatment with berbeine also attenuated ischemia-induced apoptosis and inhibited reactive astrogliosis and microglia activation. Furthermore, berberine enhanced phospho-PI3K and phospho-Akt expression in the hippocampus of ischemic gerbils. Conclusions Berberine exerted a neuroprotective effect against ischemic insult by inhibiting neuronal apoptosis via activation of the PI3K/Akt signaling pathway. The antiapoptotic effect of berberine was achieved through inhibition of reactive astrogliosis and microglia activation. Berberine may therefore serve as a therapeutic agent for stroke-induced neurourological problems. PMID:25279238

  17. oxLDL induces endothelial cell proliferation via Rho/ROCK/Akt/p27(kip1) signaling: opposite effects of oxLDL and cholesterol loading.

    PubMed

    Zhang, Chongxu; Adamos, Crystal; Oh, Myung-Jin; Baruah, Jugajyoti; Ayee, Manuela A A; Mehta, Dolly; Wary, Kishore K; Levitan, Irena

    2017-09-01

    Oxidized modifications of LDL (oxLDL) play a key role in the development of endothelial dysfunction and atherosclerosis. However, the underlying mechanisms of oxLDL-mediated cellular behavior are not completely understood. Here, we compared the effects of two major types of oxLDL, copper-oxidized LDL (Cu(2+)-oxLDL) and lipoxygenase-oxidized LDL (LPO-oxLDL), on proliferation of human aortic endothelial cells (HAECs). Cu(2+)-oxLDL enhanced HAECs' proliferation in a dose- and degree of oxidation-dependent manner. Similarly, LPO-oxLDL also enhanced HAEC proliferation. Mechanistically, both Cu(2+)-oxLDL and LPO-oxLDL enhance HAEC proliferation via activation of Rho, Akt phosphorylation, and a decrease in the expression of cyclin-dependent kinase inhibitor 1B (p27(kip1)). Both Cu(2+)-oxLDL or LPO-oxLDL significantly increased Akt phosphorylation, whereas an Akt inhibitor, MK2206, blocked oxLDL-induced increase in HAEC proliferation. Blocking Rho with C3 or its downstream target ROCK with Y27632 significantly inhibited oxLDL-induced Akt phosphorylation and proliferation mediated by both Cu(2+)- and LPO-oxLDL. Activation of RhoA was blocked by Rho-GDI-1, which also abrogated oxLDL-induced Akt phosphorylation and HAEC proliferation. In contrast, blocking Rac1 in these cells had no effect on oxLDL-induced Akt phosphorylation or cell proliferation. Moreover, oxLDL-induced Rho/Akt signaling downregulated cell cycle inhibitor p27(kip1) Preloading these cells with cholesterol, however, prevented oxLDL-induced Akt phosphorylation and HAEC proliferation. These findings provide a new understanding of the effects of oxLDL on endothelial proliferation, which is essential for developing new treatments against neovascularization and progression of atherosclerosis. Copyright © 2017 the American Physiological Society.

  18. Microarray expression profiles of genes in lung tissues of rats subjected to focal cerebral ischemia-induced lung injury following bone marrow-derived mesenchymal stem cell transplantation.

    PubMed

    Hu, Yue; Xiong, Liu-Lin; Zhang, Piao; Wang, Ting-Hua

    2017-01-01

    Ischemia-induced stroke is the most common disease of the nervous system and is associated with a high mortality rate worldwide. Cerebral ischemia may lead to remote organ dysfunction, particular in the lungs, resulting in lung injury. Nowadays, bone marrow-derived mesenchymal stem cells (BMSCs) are widely studied in clinical trials as they may provide an effective solution to the treatment of neurological and cardiac diseases; however, the underlying molecular mechanisms remain unknown. In this study, a model of permanent focal cerebral ischemia-induced lung injury was successfully established and confirmed by neurological evaluation and lung injury scores. We demonstrated that the transplantation of BMSCs (passage 3) via the tail vein into the lung tissues attenuated lung injury. In order to elucidate the underlying molecular mechanisms, we analyzed the gene expression profiles in lung tissues from the rats with focal cerebral ischemia and transplanted with BMSCs using a Gene microarray. Moreover, the Gene Ontology database was employed to determine gene function. We found that the phosphoinositide 3-kinase (PI3K)-AKT signaling pathway, transforming growth factor-β (TGF-β) and platelet-derived growth factor (PDGF) were downregulated in the BMSC transplantation groups, compared with the control group. These results suggested that BMSC transplantation may attenuate lung injury following focal cerebral ischemia and that this effect is associated with the downregulation of TGF-β, PDGF and the PI3K-AKT pathway.

  19. Intake of water with high levels of dissolved hydrogen (H2) suppresses ischemia-induced cardio-renal injury in Dahl salt-sensitive rats.

    PubMed

    Zhu, Wan-Jun; Nakayama, Masaaki; Mori, Takefumi; Nakayama, Keisuke; Katoh, Junichiro; Murata, Yaeko; Sato, Toshinobu; Kabayama, Shigeru; Ito, Sadayoshi

    2011-07-01

    Hydrogen (H(2)) reportedly produces an antioxidative effect by quenching cytotoxic oxygen radicals. We studied the biological effects of water with dissolved H(2) on ischemia-induced cardio-renal injury in a rat model of chronic kidney disease (CKD). Dahl salt-sensitive rats (7 weeks old) were allowed ad libitum drinking of filtered water (FW: dissolved H(2), 0.00 ± 0.00 mg/L) or water with dissolved H(2) produced by electrolysis (EW: dissolved H(2), 0.35 ± 0.03 mg/L) for up to 6 weeks on a 0.5% salt diet. The rats then underwent ischemic reperfusion (I/R) of one kidney and were killed a week later for investigation of the contralateral kidney and the heart. In the rats given FW, unilateral kidney I/R induced significant increases in plasma monocyte chemoattractant protein-1, methylglyoxal and blood urea nitrogen. Histologically, significant increases were found in glomerular adhesion, cardiac fibrosis, number of ED-1 (CD68)-positive cells and nitrotyrosine staining in the contralateral kidney and the heart. In rats given EW, those findings were significantly ameliorated and there were significant histological differences between rats given FW and those given EW. Consumption of EW by ad libitum drinking has the potential to ameliorate ischemia-induced cardio-renal injury in CKD model rats. This indicates a novel strategy of applying H(2) produced by water electrolysis technology for the prevention of CKD cardio-renal syndrome.

  20. Indomethacin and cyclosporin a inhibit in vitro ischemia-induced expression of ICAM-1 and chemokines in human brain endothelial cells.

    PubMed

    Zhang, W; Smith, C; Monette, R; Hutchison, J; Stanimirovic, D B

    2000-01-01

    Brain inflammation has been implicated in the development of brain edema and secondary brain damage in ischemia and trauma. Mechanisms involved in leukocyte infiltration across the blood-brain barrier are still unknown. In this study, we show that human cere-bromicrovascular endothelial cells (HCEC) subjected to a 4 h in vitro ischemia (hypoxia + glucose deprivation) followed by a 4-24 h recovery express elevated levels of ICAM-1, IL-8, and MCP-1 mRNAs (semi-quantitative RT-PCR) and secrete increased amounts of the immunoreactive chemokines IL-8 and MCP-1 (ELISA). The ischemia-induced expression of ICAM-1 in HCEC, and the expression/release of IL-8 and MCP-1 in HCEC were abolished by the non-steroid anti-inflammatory drug, indomethacin (100-300 microM). The immunosuppressant cyclosporin A (50 microM) partially reduced the ischemia-stimulated IL-8 and MCP-1 secretion by HCEC. Both indomethacin and cyclosporin A also inhibited the ischemia-induced neutrophil chemotaxis elicited by HCEC media. The study indicates that in vitro ischemia augments the expression of adhesion molecules and leukocyte chemoattractants at the site of the BBB. This ischemic pro-inflammatory activation of HCEC may constitute a key event in initiating post-ischemic inflammation, and it can be suppressed by the anti-inflammatory drugs, indomethacin and cyclosporin A.

  1. Microarray expression profiles of genes in lung tissues of rats subjected to focal cerebral ischemia-induced lung injury following bone marrow-derived mesenchymal stem cell transplantation

    PubMed Central

    Hu, Yue; Xiong, Liu-Lin; Zhang, Piao; Wang, Ting-Hua

    2017-01-01

    Ischemia-induced stroke is the most common disease of the nervous system and is associated with a high mortality rate worldwide. Cerebral ischemia may lead to remote organ dysfunction, particular in the lungs, resulting in lung injury. Nowadays, bone marrow-derived mesenchymal stem cells (BMSCs) are widely studied in clinical trials as they may provide an effective solution to the treatment of neurological and cardiac diseases; however, the underlying molecular mechanisms remain unknown. In this study, a model of permanent focal cerebral ischemia-induced lung injury was successfully established and confirmed by neurological evaluation and lung injury scores. We demonstrated that the transplantation of BMSCs (passage 3) via the tail vein into the lung tissues attenuated lung injury. In order to elucidate the underlying molecular mechanisms, we analyzed the gene expression profiles in lung tissues from the rats with focal cerebral ischemia and transplanted with BMSCs using a Gene microarray. Moreover, the Gene Ontology database was employed to determine gene function. We found that the phosphoinositide 3-kinase (PI3K)-AKT signaling pathway, transforming growth factor-β (TGF-β) and platelet-derived growth factor (PDGF) were downregulated in the BMSC transplantation groups, compared with the control group. These results suggested that BMSC transplantation may attenuate lung injury following focal cerebral ischemia and that this effect is associated with the downregulation of TGF-β, PDGF and the PI3K-AKT pathway. PMID:27922691

  2. Effect of a pre-freezing treatment with cholesterol-loaded cyclodextrins on boar sperm longevity, capacitation dynamics, ability to adhere to porcine oviductal epithelial cells in vitro and DNA fragmentation dynamics.

    PubMed

    Tomás, C; Blanch, E; Fazeli, A; Mocé, E

    2013-01-01

    The aim of this work was to examine how a pre-freezing treatment with cholesterol-loaded cyclodextrins (CLC) affects boar sperm longevity, capacitation dynamics, ability to bind to a porcine telomerase-immortalised oviductal epithelial cell line (TERT-OPEC) in vitro and DNA integrity dynamics after freeze-thawing. Although the samples treated with CLC exhibited lower sperm quality than the control samples (P<0.05) immediately after thawing, these differences disappeared (P>0.05) after long-term incubation (26h at 37 or 16°C). Additionally, the CLC-treated spermatozoa underwent similar capacitation and DNA fragmentation dynamics as the control spermatozoa (P>0.05). However, CLC-treated spermatozoa were better able to bind to TERT-OPEC in vitro (P<0.0001). In conclusion, the pre-freezing treatment of boar spermatozoa with CLC enhanced the ability of the spermatozoa to bind to TERT-OPEC in vitro, which could have an effect on the establishment of the sperm reservoir in the ampullary--isthmic junction in vivo. Additionally, frozen-thawed spermatozoa can be stored at 16°C for at least 6h without a significant observable decline in sperm quality, which could be beneficial for the transport of thawed diluted doses of spermatozoa from the laboratory to the farm.

  3. Get Your Cholesterol Checked

    MedlinePlus

    ... cholesterol levels with a blood test called a lipid profile. For the test, a nurse will take a ... blood tests that can check cholesterol, but a lipid profile gives the most information. Find out more about ...

  4. Cholesterol - Multiple Languages

    MedlinePlus

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Cholesterol URL of this page: https://medlineplus.gov/languages/cholesterol.html Other topics A-Z Expand Section ...

  5. All about Cholesterol

    MedlinePlus

    Toolkit No. 6 All About Cholesterol Managing your cholesterol and other blood fats (also called blood lipids) can help you prevent health problems. ... it’s likely that your cholesterol may be off. All of these are risk factors for diabetes, heart ...

  6. Detecting Elevated Cholesterol Levels

    PubMed Central

    Reimer, H.L.; Elford, R.W.; Shumak, S.

    1991-01-01

    To assess accuracy of blood cholesterol measurements in the office, fingerprick blood cholesterol assays by a dry reagent chemistry analyzer were compared in 151 patients with simultaneous venipuncture cholesterol assays by standard laboratory methods. Compared with the laboratory assay, seven of eight analyzers had total absolute biases less than 5%. Variability in results was comparable to that of community laboratories. PMID:21229050

  7. Cholesterol and Plants

    ERIC Educational Resources Information Center

    Behrman, E. J.; Gopalan, Venkat

    2005-01-01

    There is a widespread belief among the public and even among chemist that plants do not contain cholesterol. This wrong belief is the result of the fact that plants generally contain only small quantities of cholesterol and that analytical methods for the detection of cholesterol in this range were not developed until recently.

  8. Cholesterol and Plants

    ERIC Educational Resources Information Center

    Behrman, E. J.; Gopalan, Venkat

    2005-01-01

    There is a widespread belief among the public and even among chemist that plants do not contain cholesterol. This wrong belief is the result of the fact that plants generally contain only small quantities of cholesterol and that analytical methods for the detection of cholesterol in this range were not developed until recently.

  9. Women and Heart Disease - Physiologic Regulation of Gene Delivery and Expression: Bioreducible Polymers and Ischemia-Inducible Gene Therapies for the Treatment of Ischemic Heart Disease

    PubMed Central

    Yockman, James W.; Bull, David A.

    2009-01-01

    Ischemic heart disease (IHD) is the leading cause of death in the United States today. This year over 750,000 women will have a new or recurrent myocardial infarction. Currently, the mainstay of therapy for IHD is revascularization. Increasing evidence, however, suggests that revascularization alone is insufficient for the longer-term management of many patients with IHD. To address these issues, innovative therapies that extend beyond revascularization to protection of the myocyte and preservation of ventricular function are required. The emergence of gene therapy and proteomics offers the potential for innovative prophylactic and treatment strategies for IHD. The goal of our research is to develop therapeutic gene constructs for the treatment of myocardial ischemia that are clinically safe and effective. Toward this end, we describe the development of physiologic regulation of gene delivery and expression using bioreducible polymers and ischemia-inducible gene therapies for the potential treatment of ischemic heart disease in women. PMID:19422868

  10. A Water-Ethanol Extract from the Willow Bracket Mushroom, Phellinus igniarius (Higher Basidiomycetes), Reduces Transient Cerebral Ischemia-Induced Neuronal Death.

    PubMed

    Kim, Jin Hee; Choi, Bo Young; Kim, Hyun Jung; Kim, In Yeol; Lee, Bo Eun; Sohn, Min; Park, Hyoung Jin; Suh, Sang Won

    2015-01-01

    This study investigated the potential neuroprotective effect of a mushroom extract from Phellinus igniarius (Piwep) after transient cerebral ischemia. Ph. Igniarius, which has a history of traditional medicinal use, contains immunomodulatory compounds that have been described to have effects on the human immune system. Using a model of transient cerebral ischemia induced by both common carotid artery occlusion and hypovolemia, a water-ethanol extract precipitate of Ph. Igniarius (Piwep) was delivered intraperitoneally immediately after the insult and was injected subsequently every other day for the experimental course. Neuronal death was examined by Fluoro-Jade B staining 1 week after the insult. Piwep injection lead to decreased hippocampal neuronal death, suppression of oxidative injury, activation of microglia, and disruption of the blood-brain barrier. We conclude that Piwep potently inhibits hippocampal neuronal death following ischemia and may have a high therapeutic potential for ameliorating stroke-induced neuron death in the clinical setting.

  11. What Your Cholesterol Levels Mean

    MedlinePlus

    ... Disease Venous Thromboembolism Aortic Aneurysm More What Your Cholesterol Levels Mean Updated:Jul 5,2017 Keeping your ... stroke. This content was last reviewed April 2017. Cholesterol • Home • About Cholesterol Introduction Atherosclerosis What Your Cholesterol ...

  12. Home-Use Tests - Cholesterol

    MedlinePlus

    ... Medical Procedures In Vitro Diagnostics Home Use Tests Cholesterol Share Tweet Linkedin Pin it More sharing options ... a home-use test kit to measure total cholesterol. What cholesterol is: Cholesterol is a fat (lipid) ...

  13. Global ischemia induces lysosomal-mediated degradation of mTOR and activation of autophagy in hippocampal neurons destined to die

    PubMed Central

    Hwang, Jee-Yeon; Gertner, Michael; Pontarelli, Fabrizio; Court-Vazquez, Brenda; Bennett, Michael Vander Laan; Ofengeim, Dimitry; Zukin, Ruth Suzanne

    2017-01-01

    The mammalian target of rapamycin (mTOR) is a key regulator of cell growth, autophagy, translation, and survival. Dysregulation of mTOR signaling is associated with cancer, diabetes, and autism. However, a role for mTOR signaling in neuronal death is not well delineated. Here we show that global ischemia triggers a transient increase in mTOR phosphorylation at S2448, whereas decreasing p-mTOR and functional activity in selectively vulnerable hippocampal CA1 neurons. The decrease in mTOR coincides with an increase in biochemical markers of autophagy, pS317-ULK-1, pS14-Beclin-1, and LC3-II, a decrease in the cargo adaptor p62, and an increase in autophagic flux, a functional readout of autophagy. This is significant in that autophagy, a catabolic process downstream of mTORC1, promotes the formation of autophagosomes that capture and target cytoplasmic components to lysosomes. Inhibitors of the lysosomal (but not proteasomal) pathway rescued the ischemia-induced decrease in mTOR, consistent with degradation of mTOR via the autophagy/lysosomal pathway. Administration of the mTORC1 inhibitor rapamycin or acute knockdown of mTOR promotes autophagy and attenuates ischemia-induced neuronal death, indicating an inverse causal relation between mTOR, autophagy, and neuronal death. Our findings identify a novel and previously unappreciated mechanism by which mTOR self-regulates its own levels in hippocampal neurons in a clinically relevant model of ischemic stroke. PMID:27935582

  14. Regulation of cholesterol homeostasis.

    PubMed

    van der Wulp, Mariëtte Y M; Verkade, Henkjan J; Groen, Albert K

    2013-04-10

    Hypercholesterolemia is an important risk factor for cardiovascular disease. It is caused by a disturbed balance between cholesterol secretion into the blood versus uptake. The pathways involved are regulated via a complex interplay of enzymes, transport proteins, transcription factors and non-coding RNA's. The last two decades insight into underlying mechanisms has increased vastly but there are still a lot of unknowns, particularly regarding intracellular cholesterol transport. After decades of concentration on the liver, in recent years the intestine has come into focus as an important control point in cholesterol homeostasis. This review will discuss current knowledge of cholesterol physiology, with emphasis on cholesterol absorption, cholesterol synthesis and fecal excretion, and new (possible) therapeutic options for hypercholesterolemia.

  15. High blood cholesterol levels

    MedlinePlus

    Lipid disorders; Hyperlipoproteinemia; Hyperlipidemia; Dyslipidemia; Hypercholesterolemia ... A cholesterol test is done to diagnose a lipid disorder. Different experts recommend different starting ages. Recommended ...

  16. Cholesterol - what to ask your doctor

    MedlinePlus

    ... your doctor; What to ask your doctor about cholesterol ... What is my cholesterol level? What should my cholesterol level be? What are HDL ("good") cholesterol and LDL ("bad") cholesterol? Does my cholesterol ...

  17. Kids and Cholesterol.

    ERIC Educational Resources Information Center

    Ficklen, Ellen

    1992-01-01

    According to a 1991 National Cholesterol Education Program report, the best way to avoid heart trouble is to take early preventive measures. This means that children over age two should follow the same low-fat, low-cholesterol guidelines already recommended for adults. Sidebars contain a fat glossary and tips for cutting fat in school lunches.…

  18. Cholesterol and Kir channels

    PubMed Central

    Levitan, Irena

    2009-01-01

    To date, most of the major types of Kir channels, Kir2s, Kir3s, Kir4s and Kir6s, have been found to partition into cholesterol-rich membrane domains and/or to be regulated by changes in the level of membrane cholesterol. Surprisingly, however, in spite of the structural similarities between different Kirs, effects of cholesterol on different types of Kir channels vary from cholesterol-induced decrease in the current density (Kir2 channels) to the loss of channel activity by cholesterol depletion (Kir4 channels) and loss of channel coupling by different mediators (Kir3 and Kir6 channels). Recently, we have gained initial insights into the mechanisms responsible for cholesterol-induced suppression Kir2 channels, but mechanisms underlying cholesterol sensitivity of other Kir channels are mostly unknown. The goal of this review is to present a summary of the current knowledge of the distinct effects of cholesterol on different types of Kir channels in vitro and in vivo. PMID:19548316

  19. Electrochemical oxidation of cholesterol

    PubMed Central

    2015-01-01

    Summary Indirect cholesterol electrochemical oxidation in the presence of various mediators leads to electrophilic addition to the double bond, oxidation at the allylic position, oxidation of the hydroxy group, or functionalization of the side chain. Recent studies have proven that direct electrochemical oxidation of cholesterol is also possible and affords different products depending on the reaction conditions. PMID:25977713

  20. Cholesterol and prostate cancer.

    PubMed

    Freeman, Michael R; Solomon, Keith R

    2004-01-01

    Cholesterol is a neutral lipid that accumulates in liquid-ordered, detergent-resistant membrane domains called lipid rafts. Lipid rafts serve as membrane platforms for signal transduction mechanisms that mediate cell growth, survival, and a variety of other processes relevant to cancer. A number of studies, going back many years, demonstrate that cholesterol accumulates in solid tumors and that cholesterol homeostasis breaks down in the prostate with aging and with the transition to the malignant state. This review summarizes the established links between cholesterol and prostate cancer (PCa), with a focus on how accumulation of cholesterol within the lipid raft component of the plasma membrane may stimulate signaling pathways that promote progression to hormone refractory disease. We propose that increases in cholesterol in prostate tumor cell membranes, resulting from increases in circulating levels or from dysregulation of endogenous synthesis, results in the coalescence of raft domains. This would have the effect of sequestering positive regulators of oncogenic signaling within rafts, while maintaining negative regulators in the liquid-disordered membrane fraction. This approach toward examining the function of lipid rafts in prostate cancer cells may provide insight into the role of circulating cholesterol in malignant growth and on the potential relationship between diet and aggressive disease. Large-scale characterization of proteins that localize to cholesterol-rich domains may help unveil signaling networks and pathways that will lead to identification of new biomarkers for disease progression and potentially to novel targets for therapeutic intervention.

  1. Cellular Cholesterol Homeostasis in Alzheimer's Disease.

    PubMed

    Chang, Ta Yuan; Yamauchi, Yoshio; Hasan, Mazahir T; Chang, Catherine Cy

    2017-03-15

    Alzheimer's disease [AD] is the most common form of dementia in older adults. Currently, there is no cure for AD. The hallmark of AD is the accumulation of extracellular amyloid plaques composed of amyloid beta peptides [Abeta; especially Abeta1-42], and neurofibrillary tangles, composed of hyper-phosphorylated tau, accompanied with chronic neuroinflammation. Abeta are derived from the amyloid precursor protein APP. The oligomeric form of Abeta is probably the most neurotoxic species; its accumulation eventually forms the insoluble and aggregated amyloid plaques. ApoE is the major cholesterol transport protein in the CNS that has three alleles, of which the Apoe4 allele constitutes the major risk factor for late onset AD [LOAD]. In this review we describe the complex relationship between ApoE4, oligomeric Abeta peptides, and cholesterol homeostasis. The review consists of four parts: 1. Key elements involved in cellular cholesterol metabolism and regulation; II. Key elements involved in intracellular cholesterol trafficking; III. Links between ApoE4, Abeta, and disturbance of cholesterol homeostasis in the CNS; IV. Potential lipid based therapeutic targets to treat AD. At the end, we recommend several research topics that we believe would help in better understanding the connection between cholesterol and AD for further investigations. Copyright © 2017, The American Society for Biochemistry and Molecular Biology.

  2. Bile acid sequestrants for cholesterol

    MedlinePlus

    ... ency/patientinstructions/000787.htm Bile acid sequestrants for cholesterol To use the sharing features on this page, ... are medicines that help lower your LDL (bad) cholesterol . Too much cholesterol in your blood can stick ...

  3. The neuroprotective action of dexmedetomidine on apoptosis, calcium entry and oxidative stress in cerebral ischemia-induced rats: Contribution of TRPM2 and TRPV1 channels

    PubMed Central

    Akpınar, Hatice; Nazıroğlu, Mustafa; Övey, İshak Suat; Çiğ, Bilal; Akpınar, Orhan

    2016-01-01

    Dexmedetomidine (DEX) may act as an antioxidant through regulation of TRPM2 and TRPV1 channel activations in the neurons by reducing cerebral ischemia-induced oxidative stress and apoptosis. The neuroprotective roles of DEX were tested on cerebral ischemia (ISC) in the cultures of rat primary hippocampal and DRG neurons. Fifty-six rats were divided into five groups. A placebo was given to control, sham control, and ISC groups, respectively. In the third group, ISC was induced. The DEX and ISC+DEX groups received intraperitoneal DEX (40 μg/kg) 3, 24, and 48 hours after ISC induction. DEX effectively reversed capsaicin and cumene hydroperoxide/ADP-ribose-induced TRPV1 and TRPM2 densities and cytosolic calcium ion accumulation in the neurons, respectively. In addition, DEX completely reduced ISC-induced oxidative toxicity and apoptosis through intracellular reactive oxygen species production and depolarization of mitochondrial membrane. The DEX and ISC+DEX treatments also decreased the expression levels of caspase 3, caspase 9, and poly (ADP-ribose) polymerase in the hippocampus and DRG. In conclusion, the current results are the first to demonstrate the molecular level effects of DEX on TRPM2 and TRPV1 activation. Therefore, DEX can have remarkable neuroprotective impairment effects in the hippocampus and DRG of ISC-induced rats. PMID:27872485

  4. Transient ischemia-induced change of CCR7 immunoreactivity in neurons and its new expression in astrocytes in the gerbil hippocampus.

    PubMed

    Lee, Jae-Chul; Ahn, Ji Hyeon; Kim, In Hye; Park, Joon Ha; Yan, Bing Chun; Cho, Geum-Sil; Ohk, Taek Geun; Park, Chan Woo; Cho, Jun Hwi; Kim, Young-Myeong; Lee, Hui Young; Won, Moo-Ho

    2014-01-15

    Chemokines and their receptors are important players in organism homeostasis, development and immune response to inflammatory stimuli. In the present study, we examined effects of ischemia-reperfusion injury on the immunoreactivity and protein levels of chemokine C-C motif receptor 7 (CCR7) in the gerbil hippocampus (CA1-3 regions) after 5 min of transient global cerebral ischemia. CCR7 immunoreactivity was dramatically changed in the pyramidal neurons of the CA1, not CA2/3, region after ischemia-reperfusion. The immunoreactivity was increased after ischemia-reperfusion, and it was barely found from 5 days post-ischemia. In addition, CCR7 immunoreactivity was newly expressed in astrocytes, not microglia, in the ischemic CA1 region from 5 days post-ischemia. However, we did not observe this finding in the ischemic CA2/3 region. Furthermore, CCR7 protein levels in the ischemic CA1 region were changed like the change pattern of its immunoreactivity. These results indicate that both CCR7 immunoreactivity and protein levels are distinctively altered only in the CA1 region after transient cerebral ischemia and that the changes in CCR7 expression may be related to the ischemia-induced delayed neuronal death.

  5. Delayed IGF-1 treatment reduced long-term hypoxia-ischemia-induced brain damage and improved behavior recovery of immature rats.

    PubMed

    Zhong, Jin; Zhao, Limin; Du, Yansheng; Wei, Gang; Yao, Wei-Guo; Lee, Wei-Hua

    2009-06-01

    Cerebral hypoxia-ischemia during the perinatal period is the single most important cause of acute newborn mortality and chronic disability. Despite our increasing understanding of the mechanisms of neuronal injury, an effective clinical therapy has yet to be established to mitigate brain damage and improve the prognosis and well-being of these newborn patients. Insulin-like growth factor 1 (IGF-1) is a well-known neurotrophic factor, essential for the survival and functional maturation of immature neurons. This study demonstrated that subcutaneous administration of IGF-1 at 24 and 48 hours of recovery significantly reduced hypoxia-ischemia-induced injury to immature rat brains and improved long-term memory and cognitive behavior. IGF-1's therapeutic effects likely involve its ability to prevent delayed apoptosis, as we demonstrated in primary cortical neuronal cultures under oxygen and glucose deprivation. IGF-1's neuroprotective effects parallel the activities of phosphatidylinositol-3/Akt and its down-stream signaling pathway, suggesting a potential mechanistic link. Overall, evidence from this investigation strongly supports IGF-1's potential therapeutic use in the treatment of hypoxic-ischemic encephalopathy in newborn patients.

  6. Down-regulation of nuclear HMGB1 reduces ischemia-induced HMGB1 translocation and release and protects against liver ischemia-reperfusion injury.

    PubMed

    Zhao, Guangyuan; Fu, Cheng; Wang, Lu; Zhu, Lan; Yan, Yutao; Xiang, Ying; Zheng, Fang; Gong, Feili; Chen, Song; Chen, Gang

    2017-04-06

    Hepatocyte-specific HMGB1 deletion has been found to worsen the injury and inflammation in liver ischemia-reperfusion injury (IRI), highlighting a role for intracellular HMGB1 in cellular protection. Down-regulation of nuclear HMGB1 by small interfering RNA (siRNA) might not only decrease its injurious extracellular role by reducing its release but also serve to maintain its beneficial intracellular role, thus protecting against IRI. We established a non-lethal liver IRI model in mice via segmental hepatic warm ischemia for 1 h and reperfusion for 6 h. HMGB1-siRNA achieved a reduction of ~60-70% in the nuclear HMGB1 expression in the liver at 48 h post-treatment. Knockdown of nuclear HMGB1 expression dramatically reduced both the degree of nuclear-cytoplasmic translocation of HMGB1 during hepatic ischemia and of HMGB1 release after hepatic reperfusion, resulting in significant preservation of liver function and a marked reduction in pathological damage. Also, HMGB1-siRNA pretreatment markedly inhibited the increases in hepatic expression of TLR4, TLR2, RAGE, TNF-α, IL-1β, IL-6, MCP-1, iNOS, and COX-2 seen in control mice after hepatic reperfusion. We demonstrated for the first time that down-regulation of nuclear HMGB1 reduces ischemia-induced HMGB1 release and protects against liver IRI, which is helpful for better understanding the role of HMGB1 in organ IRI.

  7. The neuroprotective action of dexmedetomidine on apoptosis, calcium entry and oxidative stress in cerebral ischemia-induced rats: Contribution of TRPM2 and TRPV1 channels.

    PubMed

    Akpınar, Hatice; Nazıroğlu, Mustafa; Övey, İshak Suat; Çiğ, Bilal; Akpınar, Orhan

    2016-11-22

    Dexmedetomidine (DEX) may act as an antioxidant through regulation of TRPM2 and TRPV1 channel activations in the neurons by reducing cerebral ischemia-induced oxidative stress and apoptosis. The neuroprotective roles of DEX were tested on cerebral ischemia (ISC) in the cultures of rat primary hippocampal and DRG neurons. Fifty-six rats were divided into five groups. A placebo was given to control, sham control, and ISC groups, respectively. In the third group, ISC was induced. The DEX and ISC+DEX groups received intraperitoneal DEX (40 μg/kg) 3, 24, and 48 hours after ISC induction. DEX effectively reversed capsaicin and cumene hydroperoxide/ADP-ribose-induced TRPV1 and TRPM2 densities and cytosolic calcium ion accumulation in the neurons, respectively. In addition, DEX completely reduced ISC-induced oxidative toxicity and apoptosis through intracellular reactive oxygen species production and depolarization of mitochondrial membrane. The DEX and ISC+DEX treatments also decreased the expression levels of caspase 3, caspase 9, and poly (ADP-ribose) polymerase in the hippocampus and DRG. In conclusion, the current results are the first to demonstrate the molecular level effects of DEX on TRPM2 and TRPV1 activation. Therefore, DEX can have remarkable neuroprotective impairment effects in the hippocampus and DRG of ISC-induced rats.

  8. [Neuroprotective activity of the proline-containing dipeptide noopept on the model of brain ischemia induced by the middle cerebral artery occlusion].

    PubMed

    Gavrilova, S A; Us, K S; Ostrovskaia, R U; Koshelev, V B

    2006-01-01

    The influence of noopept (N-phenylacetyl-L-prolylglycine ethyl ester, GVS-111) on the extent of ischemic cortical stroke was investigated in experiments on white mongrel male rats with ischemia induced by a combination of the middle cerebral artery occlusion with ipsilateral common carotid artery ligation. Animals were treated with noopept (0.5 mg/kg, i.p.) according to the following schedule: 15 min and 2, 24, and 48 h after the occlusion. Test rats were decapitated 72 h after occlusion, brains were extracted and frozen, and thin brain slices were stained with 2,3,5-triphenyltetrazolium chloride. The slices were scanned and processed using Auc 1 computer program, which estimates the percentage of damaged area relative to that of the whole ipsilateral hemisphere. The conditions of coagulation the distal segment of middle cerebral artery were selected, which caused necrosis localized in the fronto-parietal and dorso-lateral regions of the brain cortex without any damage of subcortical structures. The extent of the brain damage in control group (treated by saline) was 18.6%, while that in the group treated with noopept was 12.2%, thus demonstrating a decrease in the infarction area by 34.5% (p < 05). The data on noopept efficacy on the model of the extensive ischemic injury of brain cortex show that this drug has good prospects for use in the neuroprotective treatment of stroke.

  9. Cholesterol and Ion Channels

    PubMed Central

    Levitan, Irena; Fang, Yun; Rosenhouse-Dantsker, Avia; Romanenko, Victor

    2010-01-01

    A variety of ion channels, including members of all major ion channel families, have been shown to be regulated by changes in the level of membrane cholesterol and partition into cholesterol-rich membrane domains. In general, several types of cholesterol effects have been described. The most common effect is suppression of channel activity by an increase in membrane cholesterol, an effect that was described for several types of inwardly-rectifying K+ channels, voltage-gated K+ channels, Ca+2 sensitive K+ channels, voltage-gated Na+ channels, N-type voltage-gated Ca+2 channels and volume-regulated anion channels. In contrast, several types of ion channels, such as epithelial amiloride-sensitive Na+ channels and Transient Receptor Potential channels, as well as some of the types of inwardly-rectifying and voltage-gated K+ channels were shown to be inhibited by cholesterol depletion. Cholesterol was also shown to alter the kinetic properties and current-voltage dependence of several voltage-gated channels. Finally, maintaining membrane cholesterol level is required for coupling ion channels to signalling cascades. In terms of the mechanisms, three general mechanisms have been proposed: (i) specific interactions between cholesterol and the channel protein, (ii) changes in the physical properties of the membrane bilayer and (iii) maintaining the scaffolds for protein-protein interactions. The goal of this review is to describe systematically the role of cholesterol in regulation of the major types of ion channels and to discuss these effects in the context of the models proposed. PMID:20213557

  10. Detecting Elevated Cholesterol Levels

    PubMed Central

    Reimer, H.L.; Elford, R.W.; Shumak, S.

    1991-01-01

    The Reflotron dry chemistry reflectance photometer was studied as a case-finding method in physicians' offices. A total of 713 adult patients had their risk factor profiles determined along with fingerprick blood cholesterol measurements. Blood cholesterol levels were classified into three categories, (<5.2 mmol/L), 51%; borderline high (5.2 to 6.1 mmol/L), 28%; and high (≥6.2 mmol/L), 21%. The physicians' predictions from clinical risk factor profiles of which patients had elevated serum cholesterol levels were inaccurate. PMID:21229051

  11. Cholesterol-lowering effect of N-(alpha-methylbenzyl)linoleamide (melinamide) in cholesterol-fed diabetic rats.

    PubMed

    Matsubara, K; Matsuzawa, Y; Jiao, S; Kihara, S; Takama, T; Nakamura, T; Tokunaga, K; Kubo, M; Tarui, S

    1988-08-01

    Cholesterol loading of diabetic rats is known to induce marked hyperlipoproteinaemia, and we have reported that enhancement of the activity of intestinal acyl-CoA:cholesterol acyltransferase (ACAT), one of the key enzymes involved in cholesterol absorption, might play an important role in the development of hypercholesterolaemia in these animals. In the present study, we have shown that treatment with N-(alpha-methylbenzyl)linoleamide (melinamide), a new hypocholesterolaemic drug, caused a substantial decrease of the enhanced intestinal ACAT activity in diabetic rats, but did not affect intestinal cholesterol esterase activity. Furthermore, marked improvement of hypercholesterolaemia in cholesterol-fed diabetic rats occurred concomitantly with the drug treatment. These results suggest that intestinal ACAT activity is closely related to the serum cholesterol level in diabetic rats, and show that melinamide lowers intestinal ACAT activity.

  12. Autophagy Regulates Cholesterol Efflux from Macrophage Foam Cells via Lysosomal Acid Lipase

    PubMed Central

    Ouimet, Mireille; Franklin, Vivian; Mak, Esther; Liao, Xianghai; Tabas, Ira; Marcel, Yves L.

    2012-01-01

    SUMMARY The lipid droplet (LD) is the major site of cholesterol storage in macrophage foam cells and is a potential therapeutic target for the treatment of atherosclerosis. Cholesterol, stored as cholesteryl esters (CEs), is liberated from this organelle and delivered to cholesterol acceptors. The current paradigm attributes all cytoplasmic CE hydrolysis to the action of neutral CE hydrolases. Here, we demonstrate an important role for lysosomes in LD CE hydrolysis in cholesterol-loaded macrophages, in addition to that mediated by neutral hydrolases. Furthermore, we demonstrate that LDs are delivered to lysosomes via autophagy, where lysosomal acid lipase (LAL) acts to hydrolyze LD CE to generate free cholesterol mainly for ABCA1-dependent efflux; this process is specifically induced upon macrophage cholesterol loading. We conclude that, in macrophage foam cells, lysosomal hydrolysis contributes to the mobilization of LD-associated cholesterol for reverse cholesterol transport. PMID:21641547

  13. Cholesterol testing and results

    MedlinePlus

    ... VLDL test results; HDL test results; Coronary risk profile results; Hyperlipidemia-results; Lipid disorder test results ... in your blood. You may also have a lipid (or coronary risk) profile, which includes: Total cholesterol Low density lipoprotein (LDL ...

  14. Compounds affecting cholesterol absorption

    NASA Technical Reports Server (NTRS)

    Hua, Duy H. (Inventor); Koo, Sung I. (Inventor); Noh, Sang K. (Inventor)

    2004-01-01

    A class of novel compounds is described for use in affecting lymphatic absorption of cholesterol. Compounds of particular interest are defined by Formula I: ##STR1## or a pharmaceutically acceptable salt thereof.

  15. Transport of cholesterol.

    PubMed

    Norum, K R; Berg, T; Helgerud, P; Drevon, C A

    1983-10-01

    .ur current model for cholesterol transport is summarized in Figure 10. In this figure we have put together the various steps in cholesterol transport that were described previously in this review. Under normal conditions, cholesterol metabolism and transport are well regulated. If the transport system is overloaded for a long time, however, hypercholesterolemia caused mainly by increased plasma LDL may develop in several species, including humans. Under such circumstances reverse transport of cholesterol may also fail, giving rise to deposits of cholesterol. Tissue macrophages may be responsible for this lipid accumulation, because receptor-mediated (adsorptive) endocytosis of lipoprotein-associated cholesterol in these cells is not under negative-feedback control. The deposits are mainly found in tissues poorly supplied with blood and lymph: the skin, tendons, the cornea, and arteries. Overload of cholesterol transport may be the result of too much fat and cholesterol in the diet, giving rise to cholesterol-rich lipoproteins from the gut and to increased production of liver (formula; see text) VLDL, which in humans ends up as LDL. In many individuals, however, no hypercholesterolemia is seen, even after eating large amounts of a "western" diet for decades; others may develop increased LDL on a relatively "prudent" diet. Obviously many of the factors and mechanisms in cholesterol transport are influenced by genetic factors. Although studies of several inborn errors of lipid metabolism have given information about some mechanisms, the quantitatively more important differences in genetic patterns, which determine whether or not a western diet will result in hyperlipidemia, are not well known. Perhaps studies of different forms of apoB and apoE and of HDL subgroups and hyper-alpha-lipoproteinemia will explain why certain individuals develop hypercholesterolemia and premature atherosclerosis. All the recent information related to cholesterol metabolism and transport

  16. MD-2 binds cholesterol.

    PubMed

    Choi, Soo-Ho; Kim, Jungsu; Gonen, Ayelet; Viriyakosol, Suganya; Miller, Yury I

    2016-02-19

    Cholesterol is a structural component of cellular membranes, which is transported from liver to peripheral cells in the form of cholesterol esters (CE), residing in the hydrophobic core of low-density lipoprotein. Oxidized CE (OxCE) is often found in plasma and in atherosclerotic lesions of subjects with cardiovascular disease. Our earlier studies have demonstrated that OxCE activates inflammatory responses in macrophages via toll-like receptor-4 (TLR4). Here we demonstrate that cholesterol binds to myeloid differentiation-2 (MD-2), a TLR4 ancillary molecule, which is a binding receptor for bacterial lipopolysaccharide (LPS) and is indispensable for LPS-induced TLR4 dimerization and signaling. Cholesterol binding to MD-2 was competed by LPS and by OxCE-modified BSA. Furthermore, soluble MD-2 in human plasma and MD-2 in mouse atherosclerotic lesions carried cholesterol, the finding supporting the biological significance of MD-2 cholesterol binding. These results help understand the molecular basis of TLR4 activation by OxCE and mechanisms of chronic inflammation in atherosclerosis.

  17. Cholesterol through the Looking Glass

    PubMed Central

    Kristiana, Ika; Luu, Winnie; Stevenson, Julian; Cartland, Sian; Jessup, Wendy; Belani, Jitendra D.; Rychnovsky, Scott D.; Brown, Andrew J.

    2012-01-01

    How cholesterol is sensed to maintain homeostasis has been explained by direct binding to a specific protein, Scap, or through altering the physical properties of the membrane. The enantiomer of cholesterol (ent-cholesterol) is a valuable tool in distinguishing between these two models because it shares nonspecific membrane effects with native cholesterol (nat-cholesterol), but not specific binding interactions. This is the first study to compare ent- and nat-cholesterol directly on major molecular parameters of cholesterol homeostasis. We found that ent-cholesterol suppressed activation of the master transcriptional regulator of cholesterol metabolism, SREBP-2, almost as effectively as nat-cholesterol. Importantly, ent-cholesterol induced a conformational change in the cholesterol-sensing protein Scap in isolated membranes in vitro, even when steps were taken to eliminate potential confounding effects from endogenous cholesterol. Ent-cholesterol also accelerated proteasomal degradation of the key cholesterol biosynthetic enzyme, squalene monooxygenase. Together, these findings provide compelling evidence that cholesterol maintains its own homeostasis not only via direct protein interactions, but also by altering membrane properties. PMID:22869373

  18. Transintestinal and Biliary Cholesterol Secretion Both Contribute to Macrophage Reverse Cholesterol Transport in Rats-Brief Report.

    PubMed

    de Boer, Jan Freark; Schonewille, Marleen; Dikkers, Arne; Koehorst, Martijn; Havinga, Rick; Kuipers, Folkert; Tietge, Uwe J F; Groen, Albert K

    2017-04-01

    Reverse cholesterol transport comprises efflux of cholesterol from macrophages and its subsequent removal from the body with the feces and thereby protects against formation of atherosclerotic plaques. Because of lack of suitable animal models that allow for evaluation of the respective contributions of biliary cholesterol secretion and transintestinal cholesterol excretion (TICE) to macrophage reverse cholesterol transport under physiological conditions, the relative importance of both pathways in this process has remained controversial. To separate cholesterol traffic via the biliary route from TICE, bile flow was mutually diverted between rats, continuously, for 3 days. Groups of 2 weight-matched rats were designated as a pair, and both rats were equipped with cannulas in the bile duct and duodenum. Bile from rat 1 was diverted to the duodenum of rat 2, whereas bile from rat 2 was rerouted to the duodenum of rat 1. Next, rat 1 was injected with [(3)H]cholesterol-loaded macrophages. [(3)H]Cholesterol secreted via the biliary route was consequently diverted to rat 2 and could thus be quantified from the feces of that rat. On the other hand, [(3)H]cholesterol tracer in the feces of rat 1 reflected macrophage-derived cholesterol excreted via TICE. Using this setup, we found that 63% of the label secreted with the fecal neutral sterols had travelled via the biliary route, whereas 37% was excreted via TICE. TICE and biliary cholesterol secretion contribute to macrophage reverse cholesterol transport in rats. The majority of macrophage-derived cholesterol is however excreted via the hepatobiliary route. © 2017 American Heart Association, Inc.

  19. Down-regulation of nuclear HMGB1 reduces ischemia-induced HMGB1 translocation and release and protects against liver ischemia-reperfusion injury

    PubMed Central

    Zhao, Guangyuan; Fu, Cheng; Wang, Lu; Zhu, Lan; Yan, Yutao; Xiang, Ying; Zheng, Fang; Gong, Feili; Chen, Song; Chen, Gang

    2017-01-01

    Hepatocyte-specific HMGB1 deletion has been found to worsen the injury and inflammation in liver ischemia-reperfusion injury (IRI), highlighting a role for intracellular HMGB1 in cellular protection. Down-regulation of nuclear HMGB1 by small interfering RNA (siRNA) might not only decrease its injurious extracellular role by reducing its release but also serve to maintain its beneficial intracellular role, thus protecting against IRI. We established a non-lethal liver IRI model in mice via segmental hepatic warm ischemia for 1 h and reperfusion for 6 h. HMGB1-siRNA achieved a reduction of ~60–70% in the nuclear HMGB1 expression in the liver at 48 h post-treatment. Knockdown of nuclear HMGB1 expression dramatically reduced both the degree of nuclear-cytoplasmic translocation of HMGB1 during hepatic ischemia and of HMGB1 release after hepatic reperfusion, resulting in significant preservation of liver function and a marked reduction in pathological damage. Also, HMGB1-siRNA pretreatment markedly inhibited the increases in hepatic expression of TLR4, TLR2, RAGE, TNF-α, IL-1β, IL-6, MCP-1, iNOS, and COX-2 seen in control mice after hepatic reperfusion. We demonstrated for the first time that down-regulation of nuclear HMGB1 reduces ischemia-induced HMGB1 release and protects against liver IRI, which is helpful for better understanding the role of HMGB1 in organ IRI. PMID:28382970

  20. Dietary Sutherlandia and Elderberry Mitigate Cerebral Ischemia-Induced Neuronal Damage and Attenuate p47phox and Phospho-ERK1/2 Expression in Microglial Cells

    PubMed Central

    Chuang, Dennis Y.; Cui, Jiankun; Simonyi, Agnes; Engel, Victoria A.; Chen, Shanyan; Fritsche, Kevin L.; Thomas, Andrew L.; Applequist, Wendy L.; Folk, William R.; Lubahn, Dennis B.; Sun, Albert Y.; Sun, Grace Y.

    2014-01-01

    Sutherlandia (Sutherlandia frutescens) and elderberry (Sambucus spp.) are used to promote health and for treatment of a number of ailments. Although studies with cultured cells have demonstrated antioxidative and anti-inflammatory properties of these botanicals, little is known about their ability to mitigate brain injury. In this study, C57BL/6 J male mice were fed AIN93G diets without or with Sutherlandia or American elderberry for 2 months prior to a 30-min global cerebral ischemia induced by occlusion of the bilateral common carotid arteries (BCCAs), followed by reperfusion for 3 days. Accelerating rotarod assessment at 24 h after BCCA occlusion showed amelioration of sensorimotor impairment in the mice fed the supplemented diets as compared with the ischemic mice fed the control diet. Quantitative digital pathology assessment of brain slides stained with cresyl violet at 3 days after ischemia/reperfusion (I/R) revealed significant reduction in neuronal cell death in both dietary groups. Immunohistochemical staining for ionized calcium-binding adapter molecule-1 demonstrated pronounced activation of microglia in the hippocampus and striatum in the ischemic brains 3 days after I/R, and microglial activation was significantly reduced in animals fed supplemented diets. Mitigation of microglial activation by the supplements was further supported by the decrease in expression of p47phox, a cytosolic subunit of NADPH oxidase, and phospho-ERK1/2, a mitogen-activated protein kinase known to mediate a number of cytoplasmic processes including oxidative stress and neuroinflammatory responses. These results demonstrate neuroprotective effect of Sutherlandia and American elderberry botanicals against oxidative and inflammatory responses to cerebral I/R. PMID:25324465

  1. Chronic Intermittent Hypobaric Hypoxia Pretreatment Ameliorates Ischemia-Induced Cognitive Dysfunction Through Activation of ERK1/2-CREB-BDNF Pathway in Anesthetized Mice.

    PubMed

    Wang, Jintian; Zhang, Shixiao; Ma, Huijuan; Yang, Shijie; Liu, Zhao; Wu, Xiaolei; Wang, Sheng; Zhang, Yi; Liu, Yixian

    2017-02-01

    Chronic intermittent hypobaric hypoxia (CIHH) has protective effects on heart and brain against ischemia injury through mobilizing endogenous adaptive mechanisms. However, whether CIHH prevents against cognitive impairment was not elucidated. The present study aimed to investigate the effect and mechanism of CIHH treatment on ischemia/reperfusion (IR)-induced cognitive dysfunction. Mice were randomly divided into 8 groups: Control, Sham, CIHH (simulating 5000 m high-altitude for 28 days, 6 h per day), IR (three 16-min occlusions of bilateral common carotid arteries interrupted by two 10-min intervals), CIHH + IR, PD98059 (inhibitor of MEK1/2) + CIHH + IR, PD98059 + Sham and PD98059 + IR group. Morris water maze and step-down passive avoidance tests were performed to evaluate the capability of learning and memory 1 month after ischemia. Thionine dyeing was to examine histological manifestations of pyramidal neurons in hippocampus CA1 region. Western blotting assay was for measurement of the protein expressions in ERK1/2-CREB-BDNF signaling pathway. There were a shorter escape latency and a longer percentage of time retaining in the target quadrant in Morris water maze test, fewer times of errors in the step-down avoidance test and a higher neuronal density of the hippocampal CA1 subfield in CIHH + IR group than in IR group. CIHH upregulated the expressions of BDNF, phosphorylated CREB, ERK1/2 and TrkB with or without ischemia. The protective effects of CIHH were abolished by PD98059 administration 15 min before ischemia. CIHH ameliorated ischemia-induced cognitive dysfunction through activation of ERK1/2-CREB-BDNF signaling pathway.

  2. Chronic Psychological Stress Accelerates Vascular Senescence and Impairs Ischemia-Induced Neovascularization: The Role of Dipeptidyl Peptidase-4/Glucagon-Like Peptide-1-Adiponectin Axis.

    PubMed

    Piao, Limei; Zhao, Guangxian; Zhu, Enbo; Inoue, Aiko; Shibata, Rei; Lei, Yanna; Hu, Lina; Yu, Chenglin; Yang, Guang; Wu, Hongxian; Xu, Wenhu; Okumura, Kenji; Ouchi, Noriyuki; Murohara, Toyoaki; Kuzuya, Masafumi; Cheng, Xian Wu

    2017-09-28

    Exposure to psychosocial stress is a risk factor for cardiovascular disease, including vascular aging and regeneration. Given that dipeptidyl peptidase-4 (DPP4) regulates several intracellular signaling pathways associated with the glucagon-like peptide-1 (GLP-1) metabolism, we investigated the role of DPP4/GLP-1 axis in vascular senescence and ischemia-induced neovascularization in mice under chronic stress, with a special focus on adiponectin -mediated peroxisome proliferator activated receptor-γ/its co-activator 1α (PGC-1α) activation. Seven-week-old mice subjected to restraint stress for 4 weeks underwent ischemic surgery and were kept under immobilization stress conditions. Mice that underwent ischemic surgery alone served as controls. We demonstrated that stress impaired the recovery of the ischemic/normal blood-flow ratio throughout the follow-up period and capillary formation. On postoperative day 4, stressed mice showed the following: increased levels of plasma and ischemic muscle DPP4 and decreased levels of GLP-1 and adiponectin in plasma and phospho-AMP-activated protein kinase α (p-AMPKα), vascular endothelial growth factor, peroxisome proliferator activated receptor-γ, PGC-1α, and Sirt1 proteins and insulin receptor 1 and glucose transporter 4 genes in the ischemic tissues, vessels, and/or adipose tissues and numbers of circulating endothelial CD31(+)/c-Kit(+) progenitor cells. Chronic stress accelerated aortic senescence and impaired aortic endothelial sprouting. DPP4 inhibition and GLP-1 receptor activation improved these changes; these benefits were abrogated by adiponectin blocking and genetic depletion. These results indicate that the DPP4/GLP-1-adiponectin axis is a novel therapeutic target for the treatment of vascular aging and cardiovascular disease under chronic stress conditions. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  3. [The food cholesterol controversy].

    PubMed

    Cichosz, Grazyna; Czeczot, Hanna

    2012-07-01

    Arteriosclerosis of blood vessels, the main cause of heart attack and stroke, is a disease of multifactor pathogenesis. Multiple experimental, clinical and epidemiologic studies indicate that free radicals and lipid oxidation products take part in aterogenesis process. Homocysteine possess also cytotoxic activity leading to degradation of elastine of internal membrane of blood vessels. Deficiency of vitamin folic acid, B12 and B6 cause homocysteine accumulation in human organism. Identifying the arteriosclerosis with oxidation of LDL-cholesterol results with faulty conclusions. Metabolism of cholesterol in human organism depends on content of n-6 and n-3 polyunsaturated fatty acids, phospholipids, fitosterols, food fiber, Lactobacillus and antioxidants in the diet. In aterogenesis antioxidant defficiency, especially long-lasting ones, are more important then amount of fat itself. Considering cholesterol intake with average food and its absorption amounting 25-30%, one can conclude that amount of cholesterol in intestine originates in 90% from liver synthesis, which is excreted with bile, and in more than ten percent--from food. This is why reduction of cholesterol intake with food only little improves blood lipid indexes.

  4. Cholesterol depletion induces autophagy

    SciTech Connect

    Cheng, Jinglei; Ohsaki, Yuki; Tauchi-Sato, Kumi; Fujita, Akikazu; Fujimoto, Toyoshi . E-mail: tfujimot@med.nagoya-u.ac.jp

    2006-12-08

    Autophagy is a mechanism to digest cells' own components, and its importance in many physiological and pathological processes is being recognized. But the molecular mechanism that regulates autophagy is not understood in detail. In the present study, we found that cholesterol depletion induces macroautophagy. The cellular cholesterol in human fibroblasts was depleted either acutely using 5 mM methyl-{beta}-cyclodextrin or 10-20 {mu}g/ml nystatin for 1 h, or metabolically by 20 {mu}M mevastatin and 200 {mu}M mevalonolactone along with 10% lipoprotein-deficient serum for 2-3 days. By any of these protocols, marked increase of LC3-II was detected by immunoblotting and by immunofluorescence microscopy, and the increase was more extensive than that caused by amino acid starvation, i.e., incubation in Hanks' solution for several hours. The induction of autophagic vacuoles by cholesterol depletion was also observed in other cell types, and the LC3-positive membranes were often seen as long tubules, >50 {mu}m in length. The increase of LC3-II by methyl-{beta}-cyclodextrin was suppressed by phosphatidylinositol 3-kinase inhibitors and was accompanied by dephosphorylation of mammalian target of rapamycin. By electron microscopy, autophagic vacuoles induced by cholesterol depletion were indistinguishable from those seen after amino acid starvation. These results demonstrate that a decrease in cholesterol activates autophagy by a phosphatidylinositol 3-kinase-dependent mechanism.

  5. Lysosomes, cholesterol and atherosclerosis

    PubMed Central

    Jerome, W Gray

    2011-01-01

    Cholesterol-engorged macrophage foam cells are a critical component of the atherosclerotic lesion. Reducing the sterol deposits in lesions reduces clinical events. Sterol accumulations within lysosomes have proven to be particularly hard to mobilize out of foam cells. Moreover, excess sterol accumulation in lysosomes has untoward effects, including a complete disruption of lysosome function. Recently, we demonstrated that treatment of sterol-engorged macrophages in culture with triglyceride-containing particles can reverse many of the effects of cholesterol on lysosomes and dramatically reduce the sterol burden in these cells. This article describes what is known about lysosomal sterol engorgement, discusses the possible mechanisms by which triglyceride could produce its effects, and evaluates the possible positive and negative effects of reducing the lysosomal cholesterol levels in foam cells. PMID:21643524

  6. Cholesterol Metabolism in CKD.

    PubMed

    Reiss, Allison B; Voloshyna, Iryna; De Leon, Joshua; Miyawaki, Nobuyuki; Mattana, Joseph

    2015-12-01

    Patients with chronic kidney disease (CKD) have a substantial risk of developing coronary artery disease. Traditional cardiovascular disease (CVD) risk factors such as hypertension and hyperlipidemia do not adequately explain the high prevalence of CVD in CKD. Both CVD and CKD are inflammatory states and inflammation adversely affects lipid balance. Dyslipidemia in CKD is characterized by elevated triglyceride levels and high-density lipoprotein levels that are both decreased and dysfunctional. This dysfunctional high-density lipoprotein becomes proinflammatory and loses its atheroprotective ability to promote cholesterol efflux from cells, including lipid-overloaded macrophages in the arterial wall. Elevated triglyceride levels result primarily from defective clearance. The weak association between low-density lipoprotein cholesterol level and coronary risk in CKD has led to controversy over the usefulness of statin therapy. This review examines disrupted cholesterol transport in CKD, presenting both clinical and preclinical evidence of the effect of the uremic environment on vascular lipid accumulation. Preventative and treatment strategies are explored.

  7. Cholesterol and prostate cancer.

    PubMed

    Pelton, Kristine; Freeman, Michael R; Solomon, Keith R

    2012-12-01

    Prostate cancer risk can be modified by environmental factors, however the molecular mechanisms affecting susceptibility to this disease are not well understood. As a result of a series of recently published studies, the steroidal lipid, cholesterol, has emerged as a clinically relevant therapeutic target in prostate cancer. This review summarizes the findings from human studies as well as animal and cell biology models, which suggest that high circulating cholesterol increases risk of aggressive prostate cancer, while cholesterol lowering strategies may confer protective benefit. Relevant molecular processes that have been experimentally tested and might explain these associations are described. We suggest that these promising results now could be applied prospectively to attempt to lower risk of prostate cancer in select populations.

  8. Cyclodextrins as catalysts for the removal of cholesterol from macrophage foam cells.

    PubMed Central

    Atger, V M; de la Llera Moya, M; Stoudt, G W; Rodrigueza, W V; Phillips, M C; Rothblat, G H

    1997-01-01

    Low concentrations of cyclodextrins (< 1.0 mM) added to serum act catalytically, accelerating the exchange of cholesterol between cells and lipoproteins. J774 macrophages incubated with serum and 2-hydroxypropyl-beta-cyclodextrin (< or = 1 mM) released fivefold more labeled cholesterol than with serum alone. Increased efflux was not accompanied by a change in cell cholesterol mass; thus, cyclodextrin functioned as a cholesterol shuttle, enhancing cholesterol bidirectional flux without changing the equilibrium cholesterol distribution between cells and medium. The addition of phospholipid vesicles to serum and cyclodextrin shifted the equilibrium distribution to favor the medium, producing rapid and extensive depletion of cell cholesterol mass. The combination of serum, phospholipid vesicles, and cyclodextrin also stimulated the rapid clearance of both free and esterified cholesterol from mouse peritoneal macrophages loaded with free and esterified cholesterol. This study: (a) demonstrates that a compound can function as a catalyst to enhance the movement of cholesterol between cells and serum, (b) illustrates the difference between cholesterol exchange and net transport in a cell/serum system, (c) demonstrates how net movement of cholesterol is linked to concentration gradients established by phospholipids, (d) provides a basis for the development of the shuttle/sink model for the first steps in reverse cholesterol transport, (e) validates the model using artificial shuttles (cyclodextrins) and sinks (large unilamellar vesicles), and (f) suggests that cyclodextrin-like cholesterol shuttles might be of pharmacological significance in treating unstable atherosclerotic plaques. PMID:9045882

  9. Cholesterol, inflammasomes, and atherogenesis

    USDA-ARS?s Scientific Manuscript database

    Plasma cholesterol levels have been strongly associated with atherogenesis, underscoring the role of lipid metabolism in defining cardiovascular disease risk. However, atherosclerotic plaque is highly dynamic and contains elements of both the innate and adaptive immune system that respond to the abe...

  10. Cholesterol: Up in Smoke.

    ERIC Educational Resources Information Center

    Raloff, Janet

    1991-01-01

    Discussed is the contribution cooked meat makes to air pollution. The dozens of compounds, including cholesterol, that are released when a hamburger is grilled are described. The potential effects of these emissions on humans and the urban environment are discussed. (KR)

  11. Cholesterol: Up in Smoke.

    ERIC Educational Resources Information Center

    Raloff, Janet

    1991-01-01

    Discussed is the contribution cooked meat makes to air pollution. The dozens of compounds, including cholesterol, that are released when a hamburger is grilled are described. The potential effects of these emissions on humans and the urban environment are discussed. (KR)

  12. Cholesterol biosynthesis in normocholesterolemic patients after cholesterol removal by plasmapheresis.

    PubMed

    Feillet, C; Cristol, J P; Michel, F; Kanouni, T; Navarro, R; Navarro, M; Monnier, L; Descomps, B

    1997-01-01

    Plasmapheresis and low-density lipoprotein (LDL)-apheresis are recognized procedures for the treatment of hyperlipidemia resistant to diet and lipid-lowering drugs and provide information on cholesterol synthesis in hypercholesterolemic patients. However, cholesterol synthesis after acute cholesterol removal from plasma has never been investigated in normocholesterolemic patients. In this study, cholesterol synthesis was evaluated in three normocholesterolemic patients by determination of plasma lathosterol, lathosterol-to-cholesterol ratio, and plasma mevalonic acid. In a short-term kinetic study, samples were collected before and after plasmapheresis and every 6 hours during 24 hours. In the second part of the study, cholesterol synthesis was evaluated daily for 3 days. In normocholesterolemic patients, cholesterol returns to basal levels in 3 days. However, cholesterol removal did not result in a significant increase in lathosterol-to-cholesterol ratio or in plasma mevalonic acid, despite a slight increase in lathosterol. In contrast, when repeated plasma exchanges induced a dramatic hypocholesterolemia (< 1 mmol/liter), an acute but transient stimulation of cholesterol synthesis was observed (lathosterol/cholesterol ratio and MVA, respectively, increase from 8.2 to 22.3 and from 28 nmol/liter to 98 nmol/liter). This study shows that cholesterol synthesis is not stimulated by plasmapheresis in normocholesterolemic patients but is enhanced in dramatic hypocholesterolemic patients (< 1 mmol/liter).

  13. Stabilization of HIF-1α modulates VEGF and Caspase-3 in the hippocampus of rats following transient global ischemia induced by asphyxial cardiac arrest.

    PubMed

    Liu, Xiao-Liang; Lu, Jian; Xing, Jihong

    2016-04-15

    Hypoxia inducible factor-1 (HIF-1) contributes to pathophysiological changes of homeostasis under conditions of oxygen deprivation as well as ischemia. In this study, we examined protein expression of subtype HIF-1α and its downstream product, namely vascular endothelial growth factor (VEGF) in the rat hippocampus after transient global ischemia induced by asphyxial cardiac arrest (CA) followed by cardiopulmonary resuscitation (CPR). We also examined the effects of stabilization of HIF-1α by systemic administration of dimethyloxalylglycine (DMOG) and ML228 on expression of VEGF receptor subtype 2 (VEGFR-2), Caspase-3 and NF-kB in the hippocampus. Ninety-six adult Sprague-Dawley rats were used in this study. The animals surviving from CPR were sacrificed 0, 3, 6 and 24h following CPR and the protein levels of HIF-1α and VEGF in the hippocampus were determined. VEGFR-2, Caspase-3 and NF-kB were also examined in control rats, and rats that survived for 24h after CPR and were given with DMOG/ML228. Moreover, neurological functions were estimated in control rats and rats with DMOG/ML228. Our results show that HIF-1α and VEGF were significantly increased in the hippocampus 3-24h after CA. Significant increases in VEGFR-2, Caspase-3 and NF-κB were observed in the hippocampus 24h after CA (P<0.05 vs. control group). Nonetheless, DMOG and ML228 significantly augmented VEGFR-2, attenuated Caspase-3 and neuronal apoptosis, and improved neurological Severity Score and tissue edema (P<0.05 vs. saline group), without affecting expression of NF-κB. Our data revealed specific signaling pathways in alleviating CA-evoked global cerebral ischemia by elucidating that HIF-1α plays an important role in regulating expression of VEGFR-2 and Caspase-3 as well as improving neurological functions and neuronal edema. The subsequent induction of HIF-1α and its target signal pathways is likely a part of the intrinsic neuroprotective effects aimed at attenuating damage as a result of

  14. Cholesterol transformations during heat treatment.

    PubMed

    Derewiaka, D; Molińska née Sosińska, E

    2015-03-15

    The aim of the study was to characterise products of cholesterol standard changes during thermal processing. Cholesterol was heated at 120°C, 150°C, 180°C and 220°C from 30 to 180 min. The highest losses of cholesterol content were found during thermal processing at 220°C, whereas the highest content of cholesterol oxidation products was observed at temperature of 150°C. The production of volatile compounds was stimulated by the increase of temperature. Treatment of cholesterol at higher temperatures i.e. 180°C and 220°C led to the formation of polymers and other products e.g. cholestadienes and fragmented cholesterol molecules. Further studies are required to identify the structure of cholesterol oligomers and to establish volatile compounds, which are markers of cholesterol transformations, mainly oxidation.

  15. What Causes High Blood Cholesterol?

    MedlinePlus

    ... this page from the NHLBI on Twitter. What Causes High Blood Cholesterol? Many factors can affect the ... in families. An inherited condition called familial hypercholesterolemia causes very high LDL cholesterol. (“Inherited” means the condition ...

  16. Cholesterol excretion and colon cancer.

    PubMed

    Broitman, S A

    1981-09-01

    Populations consuming diets high in fat and cholesterol exhibit a greater incidence of colon cancer than those consuming less fat and cholesterol. Lowering elevated serum cholesterol levels experimentally or clinically is associated with increased large-bowel tumorigenesis. Thus, cholesterol lost to the gut, either dietary or endogenously synthesized, appears to have a role in large-bowel cancer. Whether the effect(s) is mediated by increases in fecal bile acid excretion or some other mechanism is not clear.

  17. Alginic acid cell entrapment: a novel method for measuring in vivo macrophage cholesterol homeostasis

    PubMed Central

    Sontag, Timothy J.; Chellan, Bijoy; Bhanvadia, Clarissa V.; Getz, Godfrey S.; Reardon, Catherine A.

    2015-01-01

    Macrophage conversion to atherosclerotic foam cells is partly due to the balance of uptake and efflux of cholesterol. Cholesterol efflux from cells by HDL and its apoproteins for subsequent hepatic elimination is known as reverse cholesterol transport. Numerous methods have been developed to measure in vivo macrophage cholesterol efflux. Most methods do not allow for macrophage recovery for analysis of changes in cellular cholesterol status. We describe a novel method for measuring cellular cholesterol balance using the in vivo entrapment of macrophages in alginate, which retains incorporated cells while being permeable to lipoproteins. Recipient mice were injected subcutaneously with CaCl2 forming a bubble into which a macrophage/alginate suspension was injected, entrapping the macrophages. Cells were recovered after 24 h. Cellular free and esterified cholesterol mass were determined enzymatically and normalized to cellular protein. Both normal and cholesterol loaded macrophages undergo measureable changes in cell cholesterol when injected into WT and apoA-I-, LDL-receptor-, or apoE-deficient mice. Cellular cholesterol balance is dependent on initial cellular cholesterol status, macrophage cholesterol transporter expression, and apolipoprotein deficiency. Alginate entrapment allows for the in vivo measurement of macrophage cholesterol homeostasis and is a novel platform for investigating the role of genetics and therapeutic interventions in atherogenesis. PMID:25465389

  18. Facts about Blood Cholesterol. Revised.

    ERIC Educational Resources Information Center

    National Heart, Lung, and Blood Inst. (DHHS/NIH), Bethesda, MD.

    This fact sheet offers information on blood cholesterol and its implications for a healthy heart. An explanation is given of the known facts about cholesterol and how it affects the body. A chart is provided that lists various foods and their fat and cholesterol contents. (JD)

  19. How to Get Your Cholesterol Tested

    MedlinePlus

    ... Thromboembolism Aortic Aneurysm More How To Get Your Cholesterol Tested Updated:Apr 3,2017 Cholesterol plays a ... factors for heart disease and stroke . How is cholesterol tested? A cholesterol screening measures your level of ...

  20. Cholesterol crystal embolism (atheroembolism)

    PubMed Central

    VENTURELLI, CHIARA; JEANNIN, GUIDO; SOTTINI, LAURA; DALLERA, NADIA; SCOLARI, FRANCESCO

    2006-01-01

    Cholesterol crystal embolism, known as atheroembolic disease, is caused by showers of cholesterol crystals from an atherosclerotic plaque that occludes small arteries. Embolization can occur spontaneously or as an iatrogenic complication from an invasive vascular procedure (angiography or vascular surgery) and after anticoagulant therapy. The atheroembolism can give rise to different degrees of renal impairment. Some patients show a moderate loss of renal function, others severe renal failure requiring dialysis. Renal outcome can be variable: some patients deteriorate or remain on dialysis, some improve and some remain with chronic renal impairment. Clinically, three types of atheroembolic renal disease have been described: acute, subacute or chronic. More frequently a progressive loss of renal function occurs over weeks. Atheroembolization can involve the skin, gastrointestinal system and central nervous system. The diagnosis is difficult and controversial for the protean extrarenal manifestations. In the past, the diagnosis was often made post-mortem. In the last 10 yrs, awareness of atheroembolic renal disease has improved. The correct diagnosis requires the clinician to be alert. The typical patient is a white male aged >60 yrs with a history of hypertension, smoking and arterial disease. The presence of a classic triad (precipitating event, renal failure and peripheral cholesterol crystal embolization) suggests the diagnosis. This can be confirmed by a biopsy of the target organs. A specific treatment is lacking; however, it is an important diagnosis to make because an aggressive therapeutic approach can be associated with a more favorable clinical outcome. PMID:21977265

  1. Cholesterol crystal embolism (atheroembolism).

    PubMed

    Venturelli, Chiara; Jeannin, Guido; Sottini, Laura; Dallera, Nadia; Scolari, Francesco

    2006-01-01

    Cholesterol crystal embolism, known as atheroembolic disease, is caused by showers of cholesterol crystals from an atherosclerotic plaque that occludes small arteries. Embolization can occur spontaneously or as an iatrogenic complication from an invasive vascular procedure (angiography or vascular surgery) and after anticoagulant therapy. The atheroembolism can give rise to different degrees of renal impairment. Some patients show a moderate loss of renal function, others severe renal failure requiring dialysis. Renal outcome can be variable: some patients deteriorate or remain on dialysis, some improve and some remain with chronic renal impairment. Clinically, three types of atheroembolic renal disease have been described: acute, subacute or chronic. More frequently a progressive loss of renal function occurs over weeks. Atheroembolization can involve the skin, gastrointestinal system and central nervous system. The diagnosis is difficult and controversial for the protean extrarenal manifestations. In the past, the diagnosis was often made post-mortem. In the last 10 yrs, awareness of atheroembolic renal disease has improved. The correct diagnosis requires the clinician to be alert. The typical patient is a white male aged >60 yrs with a history of hypertension, smoking and arterial disease. The presence of a classic triad (precipitating event, renal failure and peripheral cholesterol crystal embolization) suggests the diagnosis. This can be confirmed by a biopsy of the target organs. A specific treatment is lacking; however, it is an important diagnosis to make because an aggressive therapeutic approach can be associated with a more favorable clinical outcome.

  2. The cholesterol content of the erythrocyte membrane is an important determinant of phosphatidylserine exposure.

    PubMed

    van Zwieten, Rob; Bochem, Andrea E; Hilarius, Petra M; van Bruggen, Robin; Bergkamp, Ferry; Hovingh, G Kees; Verhoeven, Arthur J

    2012-12-01

    Maintenance of the asymmetric distribution of phospholipids across the plasma membrane is a prerequisite for the survival of erythrocytes. Various stimuli have been shown to induce scrambling of phospholipids and thereby exposure of phosphatidylserine (PS). In two types of patients, both with aberrant plasma cholesterol levels, we observed an aberrant PS exposure in erythrocytes upon stimulation. We investigated the effect of high and low levels of cholesterol on the ATP-dependent flippase, which maintains phospholipid asymmetry, and the ATP-independent scrambling activity, which breaks down phospholipid asymmetry. We analyzed erythrocytes of a patient with spur cell anemia, characterized by elevated plasma cholesterol, and the erythrocytes of Tangier disease patients with very low levels of plasma cholesterol. In normal erythrocytes, loaded with cholesterol or depleted of cholesterol in vitro, the same analyses were performed. Changes in the cholesterol/phospholipid ratio of erythrocytes had marked effects on PS exposure upon cell activation. Excess cholesterol profoundly inhibited PS exposure, whereas cholesterol depletion led to increased PS exposure. The activity of the ATP-dependent flippase was not changed, suggesting a major influence of cholesterol on the outward translocation of PS. The effects of cholesterol were not accompanied by eminent changes in cytoskeletal and membrane proteins. These findings emphasize the importance of cholesterol exchange between circulating plasma and the erythrocyte membrane as determinant for phosphatidylserine exposure in erythrocytes.

  3. Cholesterol metabolism in Huntington disease.

    PubMed

    Karasinska, Joanna M; Hayden, Michael R

    2011-09-06

    The CNS is rich in cholesterol, which is essential for neuronal development and survival, synapse maturation, and optimal synaptic activity. Alterations in brain cholesterol homeostasis are linked to neurodegeneration. Studies have demonstrated that Huntington disease (HD), a progressive and fatal neurodegenerative disorder resulting from polyglutamine expansion in the huntingtin protein, is associated with changes in cellular cholesterol metabolism. Emerging evidence from human and animal studies indicates that attenuated brain sterol synthesis and accumulation of cholesterol in neuronal membranes represent two distinct mechanisms occurring in the presence of mutant huntingtin that influence neuronal survival. Increased knowledge of how changes in intraneuronal cholesterol metabolism influence the pathogenesis of HD will provide insights into the potential application of brain cholesterol regulation as a therapeutic strategy for this devastating disease.

  4. The E693Δ (Osaka) mutation in amyloid precursor protein potentiates cholesterol-mediated intracellular amyloid β toxicity via its impaired cholesterol efflux.

    PubMed

    Nomura, Sachiko; Umeda, Tomohiro; Tomiyama, Takami; Mori, Hiroshi

    2013-12-01

    It has been shown that amyloid β (Aβ) secretion regulates cholesterol efflux from cells and that the E693Δ (Osaka) mutation in amyloid precursor protein (APP) promotes intracellular accumulation of Aβ and thus reduces its secretion. These findings led us to speculate that APP with the Osaka mutation (APPOSK ) might have a defect in cholesterol efflux and thus cause cellular malfunction. We therefore examined the effects of this mutation on intracellular cholesterol transport and efflux in cultured cells. Upon cholesterol loading, APPOSK -expressing cells exhibited higher levels of cellular cholesterol than wild-type APP-expressing cells, suggesting impaired cholesterol efflux. It is known that, after its internalization, cholesterol is transported from the endosomes to the endoplasmic reticulum (ER) and Golgi apparatus and then to the plasma membrane. In APPOSK -expressing cells, cholesterol accumulated with Aβ in the ER and Golgi apparatus and alone in endosomes/lysosomes. These results imply that the mutation-induced disturbance of Aβ trafficking from the ER to the plasma membrane affects cholesterol transport to cause cholesterol accumulation in the ER and Golgi apparatus and, consequently, in endosomes. Furthermore, we detected an enhanced mitochondrial accumulation of Aβ and cholesterol in APPOSK -expressing cells, and this was accompanied by an increase in the generation of reactive oxygen species (ROS). The present findings suggest that Aβ trafficking is important for intracellular cholesterol transport and efflux and that the Osaka mutation potentiates cholesterol-dependent exacerbation of intracellular Aβ toxicity, i.e. Aβ-induced ROS generation, by disturbing Aβ-mediated cholesterol efflux from the cell. Copyright © 2013 Wiley Periodicals, Inc.

  5. Recent advances in cholesterol chemistry.

    PubMed

    Morzycki, Jacek W

    2014-05-01

    This review article presents advances in cholesterol chemistry since 2000. Various transformations (chemical, enzymatic, electrochemical, etc.) of cholesterol are presented. A special emphasis is given to cholesterol oxidation reactions, but also substitution of the 3β-hydroxyl group, addition to the C5-C6 double bond, C-H functionalization, and C-C bond forming reactions are discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Food prices and blood cholesterol.

    PubMed

    Rahkovsky, Ilya; Gregory, Christian A

    2013-01-01

    Cardiovascular diseases (CVD) cost Americans billions of dollars per year. High cholesterol levels, which are closely related to dietary habits, are a major contributor to CVD. In this article, we study whether changes in food prices are related to cholesterol levels and whether taxes or subsidies on particular foods would be effective in lowering cholesterol levels and, consequently, CVD costs. We find that prices of vegetables, processed foods, whole milk and whole grains are significantly associated with blood cholesterol levels. Having analyzed the costs and benefits of government interventions, we find that a subsidy of vegetables and whole grains would be an efficient way to reduce CVD expenditures.

  7. Cholesterol self-powered biosensor.

    PubMed

    Sekretaryova, Alina N; Beni, Valerio; Eriksson, Mats; Karyakin, Arkady A; Turner, Anthony P F; Vagin, Mikhail Yu

    2014-10-07

    Monitoring the cholesterol level is of great importance, especially for people with high risk of developing heart disease. Here we report on reagentless cholesterol detection in human plasma with a novel single-enzyme, membrane-free, self-powered biosensor, in which both cathodic and anodic bioelectrocatalytic reactions are powered by the same substrate. Cholesterol oxidase was immobilized in a sol-gel matrix on both the cathode and the anode. Hydrogen peroxide, a product of the enzymatic conversion of cholesterol, was electrocatalytically reduced, by the use of Prussian blue, at the cathode. In parallel, cholesterol oxidation catalyzed by mediated cholesterol oxidase occurred at the anode. The analytical performance was assessed for both electrode systems separately. The combination of the two electrodes, formed on high surface-area carbon cloth electrodes, resulted in a self-powered biosensor with enhanced sensitivity (26.0 mA M(-1) cm(-2)), compared to either of the two individual electrodes, and a dynamic range up to 4.1 mM cholesterol. Reagentless cholesterol detection with both electrochemical systems and with the self-powered biosensor was performed and the results were compared with the standard method of colorimetric cholesterol quantification.

  8. [The real measurement of non-HDL-cholesterol: Atherogenic cholesterol].

    PubMed

    Millán, Jesús; Hernández-Mijares, Antonio; Ascaso, Juan F; Blasco, Mariano; Brea, Angel; Díaz, Ángel; González-Santos, Pedro; Mantilla, Teresa; Pedro-Botet, Juan; Pintó, Xavier

    Lowe density lipoproteins (LDL) are the causal agent of cardiovascular diseases. In practice, we identify LDL with cholesterol transported in LDL (cLDL). So, cLDL has become the major target for cardiovascular prevention. Howewer, we have progressive evidences about the role of triglycerides rich lipoproteins, particularly those very low density lipoprotein (VLDL) in promotion and progression of atherosclerosis, that leads cholesterol in VLDL and its remanents as a potential therapeutic target. This feature is particularly important and of a great magnitude, in patients with hypertiglyceridemia. We can to considere, that the non-HDL cholesterol -cLDL+cVLDL+c-remmants+Lp(a)- is the real measurement of atherogenic cholesterol. In addition, non-HDL-cholesterol do not show any variations between postprandial states. In fact, non-HDL-cholesterol should be an excellent marker of atherogenic cholesterol, and an major therapeutic target in patients with atherogenic dyslipidaemia. According with different clinical trials and with the epidemiological and mendelian studies, in patients with high cardiovascular risk, optimal level of cLDL will be under 70mg/dl, and under 100 ng/dl for non-HDL-cholesterol; and in high risk patients, 100mg/dl and 130mg/dl, respectively. Copyright © 2016. Publicado por Elsevier España, S.L.U.

  9. Food combinations for cholesterol lowering.

    PubMed

    Harland, Janice I

    2012-12-01

    Reducing elevated LDL-cholesterol is a key public health challenge. There is substantial evidence from randomised controlled trials (RCT) that a number of foods and food components can significantly reduce LDL-cholesterol. Data from RCT have been reviewed to determine whether effects are additive when two or more of these components are consumed together. Typically components, such as plant stanols and sterols, soya protein, β-glucans and tree nuts, when consumed individually at their target rate, reduce LDL-cholesterol by 3-9 %. Improved dietary fat quality, achieved by replacing SFA with unsaturated fat, reduces LDL-cholesterol and can increase HDL-cholesterol, further improving blood lipid profile. It appears that the effect of combining these interventions is largely additive; however, compliance with multiple changes may reduce over time. Food combinations used in ten 'portfolio diet' studies have been reviewed. In clinical efficacy studies of about 1 month where all foods were provided, LDL-cholesterol is reduced by 22-30 %, whereas in community-based studies of >6 months' duration, where dietary advice is the basis of the intervention, reduction in LDL-cholesterol is about 15 %. Inclusion of MUFA into 'portfolio diets' increases HDL-cholesterol, in addition to LDL-cholesterol effects. Compliance with some of these dietary changes can be achieved more easily compared with others. By careful food component selection, appropriate to the individual, the effect of including only two components in the diet with good compliance could be a sustainable 10 % reduction in LDL-cholesterol; this is sufficient to make a substantial impact on cholesterol management and reduce the need for pharmaceutical intervention.

  10. Crystal Structure of Δ(185–243)apoA-I Suggests a Mechanistic Framework for the Protein Adaptation to the Changing Lipid Load in Good Cholesterol: From Flatland to Sphereland via Double Belt, Belt-Buckle, Double Hairpin and Trefoil/Tetrafoil

    PubMed Central

    Gursky, Olga

    2012-01-01

    ApoA-I is the major protein of plasma high-density lipoproteins (HDL), macromolecular assemblies of proteins and lipids that remove cell cholesterol and protect against atherosclerosis. HDL heterogeneity, large size (7.7–12 nm) and ability to exchange proteins have prevented high-resolution structural analysis. Low-resolution studies showed that two apoA-I molecules form an antiparallel α-helical “double belt” around an HDL particle. Atomic-resolution structure of the C-terminal truncated lipid-free Δ(185–243)apoA-I, determined recently by Mei and Atkinson, provides unprecedented new insights into HDL structure-function. It allows us to propose a molecular mechanism for the adaptation of the full-length protein to increasing lipid load during cholesterol transport. ApoA-I conformations on the small, mid-size and large HDL are proposed based on the tandem α-helical repeats and the crystal structure of Δ(185–243)apoA-I, and are validated by comparison with extensive biophysical data reported by many groups. In our models, the central half of the double belt (“constant” segment 66–184) is structurally conserved while the N- and C-terminal half (“variable” segments 1–65 and 185–243) re-arranges upon HDL growth. This includes incremental unhinging of the N-terminal bundle around two flexible regions containing G39 and G65 to elongate the belt, along with concerted swing motion of the double belt around G65-P66 and G185–G186 hinges that are aligned on various-size particles, to confer 2D surface curvature to spherical HDL. The proposed conformational ensemble integrates and improves several existing HDL models. It helps provide a structural framework necessary to understand functional interactions with over 60 other HDL-associated proteins and, ultimately, improve cardioprotective function of HDL. PMID:23041415

  11. Concise Review: Are Stimulated Somatic Cells Truly Reprogrammed into an ES/iPS-Like Pluripotent State? Better Understanding by Ischemia-Induced Multipotent Stem Cells in a Mouse Model of Cerebral Infarction

    PubMed Central

    Nakagomi, Takayuki; Nakano-Doi, Akiko; Narita, Aya; Matsuyama, Tomohiro

    2015-01-01

    Following the discovery of pluripotent stem (PS) cells such as embryonic stem (ES) and induced pluripotent stem (iPS) cells, there has been a great hope that injured tissues can be repaired by transplantation of ES/iPS-derived various specific types of cells such as neural stem cells (NSCs). Although PS cells can be induced by ectopic expression of Yamanaka's factors, it is known that several stimuli such as ischemia/hypoxia can increase the stemness of somatic cells via reprogramming. This suggests that endogenous somatic cells acquire stemness during natural regenerative processes following injury. In this study, we describe whether somatic cells are converted into pluripotent stem cells by pathological stimuli without ectopic expression of reprogramming factors based on the findings of ischemia-induced multipotent stem cells in a mouse model of cerebral infarction. PMID:25945100

  12. Global ischemia-induced increases in the gap junctional proteins connexin 32 (Cx32) and Cx36 in hippocampus and enhanced vulnerability of Cx32 knock-out mice.

    PubMed

    Oguro, K; Jover, T; Tanaka, H; Lin, Y; Kojima, T; Oguro, N; Grooms, S Y; Bennett, M V; Zukin, R S

    2001-10-01

    Gap junctions are conductive channels that connect the interiors of coupled cells. In the hippocampus, GABA-containing hippocampal interneurons are interconnected by gap junctions, which mediate electrical coupling and synchronous firing and thereby promote inhibitory transmission. The present study was undertaken to examine the hypothesis that the gap junctional proteins connexin 32 (Cx32; expressed by oligodendrocytes, interneurons, or both), Cx36 (expressed by interneurons), and Cx43 (expressed by astrocytes) play a role in defining cell-specific patterns of neuronal death in hippocampus after global ischemia in mice. Global ischemia did not significantly alter Cx32 and Cx36 mRNA expression and slightly increased Cx43 mRNA expression in the vulnerable CA1, as assessed by Northern blot analysis and in situ hybridization. Global ischemia induced a selective increase in Cx32 and Cx36 but not Cx43 protein abundance in CA1 before onset of neuronal death, as assessed by Western blot analysis. The increase in Cx32 and Cx36 expression was intense and specific to parvalbumin-positive inhibitory interneurons of CA1, as assessed by double immunofluorescence. Protein abundance was unchanged in CA3 and dentate gyrus. The finding of increase in connexin protein without increase in mRNA suggests regulation of Cx32 and Cx36 expression at the translational or post-translational level. Cx32(Y/-) null mice exhibited enhanced vulnerability to brief ischemic insults, consistent with a role for Cx32 gap junctions in neuronal survival. These findings suggest that Cx32 and Cx36 gap junctions may contribute to the survival and resistance of GABAergic interneurons, thereby defining cell-specific patterns of global ischemia-induced neuronal death.

  13. Serum cholesterol in cerebral malignancies.

    PubMed

    Grieb, P; Ryba, M S; Jagielski, J; Gackowski, W; Paczkowski, P; Chrapusta, S J

    1999-01-01

    Reduced blood cholesterol levels were reported in patients with a variety of malignant peripheral tumors. This fact is likely related to increased cholesterol demand by proliferating tumor cells. The question arises whether this 'tumor-associated hypocholesterolemia' occurs also in patients with brain tumors, and--if it does not--whether its absence can be related to the location of the tumors. We have compared fasting serum total cholesterol levels among three groups of patients: 52 patients with gliomas, 56 patients with symptomatic metastatic brain tumors, and 50 patients harboring malignant tumors of peripheral location but showing no clinical signs of brain metastases. Patients in the last group, despite being--on an average--more age-advanced, had lower total serum cholesterol levels than either the patients with gliomas, or the patients with brain metastases. No difference in the cholesterol levels was found between the two latter groups, and a majority of these patients had borderline or elevated cholesterol levels. This apparent absence of 'tumor-associated hypocholesterolemia' in brain tumor patients may be related to either brain tumors' ability to synthesize cholesterol de novo and their reduced dependence on peripheral cholesterol supply, the existence of brain tumor-blood barrier, effect of medications used to counteract brain edema and seizures, or a combination of these factors.

  14. Epigenetic regulation of cholesterol homeostasis

    PubMed Central

    Meaney, Steve

    2014-01-01

    Although best known as a risk factor for cardiovascular disease, cholesterol is a vital component of all mammalian cells. In addition to key structural roles, cholesterol is a vital biochemical precursor for numerous biologically important compounds including oxysterols and bile acids, as well as acting as an activator of critical morphogenic systems (e.g., the Hedgehog system). A variety of sophisticated regulatory mechanisms interact to coordinate the overall level of cholesterol in cells, tissues and the entire organism. Accumulating evidence indicates that in additional to the more “traditional” regulatory schemes, cholesterol homeostasis is also under the control of epigenetic mechanisms such as histone acetylation and DNA methylation. The available evidence supporting a role for these mechanisms in the control of cholesterol synthesis, elimination, transport and storage are the focus of this review. PMID:25309573

  15. Prion Infection Impairs Cholesterol Metabolism in Neuronal Cells*

    PubMed Central

    Cui, Huanhuan L.; Guo, Belinda; Scicluna, Benjamin; Coleman, Bradley M.; Lawson, Victoria A.; Ellett, Laura; Meikle, Peter J.; Bukrinsky, Michael; Mukhamedova, Nigora; Sviridov, Dmitri; Hill, Andrew F.

    2014-01-01

    Conversion of prion protein (PrPC) into a pathological isoform (PrPSc) during prion infection occurs in lipid rafts and is dependent on cholesterol. Here, we show that prion infection increases the abundance of cholesterol transporter, ATP-binding cassette transporter type A1 (ATP-binding cassette transporter type A1), but reduces cholesterol efflux from neuronal cells leading to the accumulation of cellular cholesterol. Increased abundance of ABCA1 in prion disease was confirmed in prion-infected mice. Mechanistically, conversion of PrPC to the pathological isoform led to PrPSc accumulation in rafts, displacement of ABCA1 from rafts and the cell surface, and enhanced internalization of ABCA1. These effects were abolished with reversal of prion infection or by loading cells with cholesterol. Stimulation of ABCA1 expression with liver X receptor agonist or overexpression of heterologous ABCA1 reduced the conversion of prion protein into the pathological form upon infection. These findings demonstrate a reciprocal connection between prion infection and cellular cholesterol metabolism, which plays an important role in the pathogenesis of prion infection in neuronal cells. PMID:24280226

  16. Cholesterol biosensors based on oxygen sensing alginate-silica microspheres.

    PubMed

    Prasad, Janak; Joshi, Abhijeet; Jayant, Rahul Dev; Srivastava, Rohit

    2011-09-01

    Cholesterol determination in body is important in diagnosis of diseases like coronary heart disease, arteriosclerosis, diabetes, and obstructive jaundice. This research aims at developing fluorimetric cholesterol biosensors based on self-assembled mesoporous alginate-silica (Algilica) microspheres. For preparing the biosensor, Pt-(II)-octaethylporphine (PtOEP; oxygen sensitive metalloporphyrin) dye has been loaded in the Algilica microspheres using the solvent-mediated precipitation method. Cholesterol oxidase (ChOx) was then covalently conjugated to PtOEP/Algilica microspheres using EDC and NHS reagents. PtOEP dye and enzyme encapsulation, activity and stability were then analyzed. Layer-by-layer self-assembly was finally performed using PAH and PSS polyelectrolytes to minimize leaching of the biosensor components. The prepared biosensor exhibited linearity over a range of 0.77-2.5 mM O(2) (K(SV) : 0.097/mM of O(2) ) obtained using from Stern-Volmer plots. The biosensor response to standard cholesterol displayed a linear analytical range from 1.25 to 10 mM of cholesterol with regression coefficient of 0.996 (1.25-3.75 mM), 0.976 (1.25-6 mM), and 0.959 (1.25-10 mM) and response time of 10 min. Thus, the prepared cholesterol biosensor shows great potential in the diagnosis of hypercholesterolemia. Copyright © 2011 Wiley Periodicals, Inc.

  17. Lateral organization of cholesterol molecules in lipid-cholesterol assemblies.

    SciTech Connect

    Singh, Rajiv R. P.; Slepoy, Alexander; Sengupta, Pinaki; Cox, Daniel L.

    2005-05-01

    We present results of an off-lattice simulation of a two-component planar system, as a model for lateral organization of cholesterol molecules in lipid-cholesterol assemblies. We explore the existence of 'superlattice' structures even in fluid systems, in the absence of an underlying translational long-range order, and study their coupling to hexatic or bond-orientational order. We discuss our results in context of geometric superlattice theories and 'condensation complexes' in understanding a variety of experiments in artificial lipid-cholesterol assemblies.

  18. Cholesterol metabolism, LDL, and the LDL receptor

    SciTech Connect

    Myant, N.B. )

    1990-01-01

    This book covers cholesterol and metabolism. Paper include: The LDL Receptor in Perspective, Cholesterol in Animal Tissues, HMG-CoA Reductase. acetyl-CoA: Cholesterol Acyltransferase, and LDL: Physical and Chemical Characteristics.

  19. Understand Your Risk for High Cholesterol

    MedlinePlus

    ... Aortic Aneurysm More Understand Your Risk for High Cholesterol Updated:Apr 1,2016 LDL (bad) cholesterol is ... content was last reviewed on 04/21/2014. Cholesterol Guidelines: Putting the pieces together Myth vs. Truth – ...

  20. Cholesterol metabolism and colon cancer.

    PubMed

    Broitman, S A; Cerda, S; Wilkinson, J

    1993-01-01

    While epidemiologic and concordant experimental data indicate a direct relationship between dietary fat (and presumably caloric) intake and the development of colon cancer, the effect of dietary cholesterol on this disease is still not clear. However, there appears to be a developing literature concerning an inverse relationship between serum and plasma cholesterol levels, and the risk for colon cancer. Findings that low serum cholesterol levels are apparent as early as ten years prior to the detection of colon cancer implies that sub clinical disease is probably not involved initially in this process. The possibility of low serum cholesterol as a bio-marker was considered in epidemiologic studies which focused upon obese men with lower than normal serum cholesterol levels who were found to be at increased risk to colon cancer. While the relationship between low serum cholesterol and colonic or intestinal cholesterol metabolism is presently not understood, current genetic studies provide a promising though as yet unexplored potential association. Alterations which occur during the developmental progression of colonic cancer include changes in chromosome 5, which also carries two genes vital to the biosynthesis and regulation of systemic and cellular cholesterol metabolism, 3-hydroxy-3-methylglutaryl coenzyme A synthase, and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCoA R). Regulation of cholesterol metabolism in intestinal cells in vivo and in vitro varies from that seen in normal fibroblasts or hepatocytes in terms of exogenous sources of cholesterol and how these sources regulate internal synthesis. Colonic cancer cells have been used to assess small bowel enterocyte cholesterol metabolism, which has been possible because of their ability to differentiate in culture, however information regarding true colonic enterocyte cholesterol metabolism is relatively scarce. Colonic cancer cells have been shown to possess a diminished or nonexistent ability to use

  1. The impairment of cholesterol metabolism in Huntington disease.

    PubMed

    Leoni, Valerio; Caccia, Claudio

    2015-08-01

    Huntington disease (HD), an autosomal dominant neurodegenerative disorder caused by an abnormal expansion of CAG trinucleotide repeat in the Huntingtin (HTT) gene, is characterized by extensive neurodegeneration of striatum and cortex and severe diffuse atrophy at MRI. The expression of genes involved in the cholesterol biosynthetic pathway and the amount of cholesterol, lanosterol, lathosterol and 24S-hydroxycholesterol were reduced in murine models of HD. In case of HD-patients, the decrease of plasma 24OHC follows disease progression proportionally to motor and neuropsychiatric dysfunction and MRI brain atrophy, together with lanosterol and lathosterol (markers of cholesterol synthesis), and 27-hydroxycholesterol. A significant reduction of total plasma cholesterol was observed only in advanced stages. It is likely that mutant HTT decreases the maturation of SREBP and the up-regulation LXR and LXR-targeted genes (SREBP, ABCG1 and ABCG4, HMGCoA reductase, ApoE) resulting into a lower synthesis and transport of cholesterol from astrocytes to neurons via ApoE. In primary oligodendrocytes, mutant HTT inhibited the regulatory effect of PGC1α on cholesterol metabolism and on the expression of MBP. HTT seems to play a regulatory role in lipid metabolism. The impairment of the cholesterol metabolism was found to be proportional to the CAG repeat length and to the load of mutant HTT. A dysregulation on PGC1α and mitochondria dysfunction may be involved in an overall reduction of acetyl-CoA and ATP synthesis, contributing to the cerebral and whole body cholesterol impairment. This article is part of a Special Issue entitled Brain Lipids.

  2. Think Again About Cholesterol Survey.

    PubMed

    Catapano, Alberico L; Wiklund, Olov

    2015-12-01

    Cardiovascular disease (CVD) is still the main cause of death in Europe. Elevated plasma cholesterol, specifically low-density lipoprotein cholesterol (LDL-C), is the main causative risk factor for CVD, most prominently associated with coronary heart disease. A widespread disinformation about cholesterol and CVD is one factor underlying a poor compliance to lipid-lowering therapy. To investigate how cholesterol, CVD and cholesterol reduction is perceived in the population, a survey was commissioned by the European Atherosclerosis Society (EAS). Nearly half of people above 25 years of age are most worried about cancer (45%), compared to just over one in four who are worried about heart disease (27%). A majority believe being overweight (72%), blood pressure (70%) and smoking (67%) most affect heart health, far more than note cholesterol (59%) and family history (39%). The majority of adults recognize that high LDL (or "bad") cholesterol should be a health priority for everyone, including those younger than 40 and those who are not overweight. However, 1 in 4 (25%) incorrectly believe that it does not need to be a concern until someone shows signs or symptoms. Although 89% of adults surveyed agreed it is important for people to know whether or not they have high LDL-C, an overwhelming 92% did not know their LDL-C levels or had never had their cholesterol levels tested. A high 63% had never heard of familial hypercholesterolemia: France had the lowest level of awareness (41%) to Denmark with a high 80%, and the association of the disease with high levels of LDL-C is quite poor (only 36%), with Sweden only at 22% versus a high in Spain of 54%. A large part of the people participating in the survey were quite uncertain about the modality of transmission for familial hypercholesterolemia in the family. All in all, this survey highlights the need for more information among citizens for the role of cholesterol in determining CVD.

  3. HDL Cholesterol: How to Boost Your 'Good' Cholesterol

    MedlinePlus

    ... are better. By Mayo Clinic Staff High-density lipoprotein (HDL) is known as the "good" cholesterol because ... bloodstream attached to proteins. These proteins are called lipoproteins. Low-density lipoprotein. High levels of low-density ...

  4. Lecithin:Cholesterol Acyltransferase (LCAT) Deficiency Promotes Differentiation of Satellite Cells to Brown Adipocytes in a Cholesterol-dependent Manner.

    PubMed

    Nesan, Dinushan; Tavallaee, Ghazaleh; Koh, Deborah; Bashiri, Amir; Abdin, Rawand; Ng, Dominic S

    2015-12-18

    Our laboratory previously reported that lecithin:cholesterol acyltransferase (LCAT) and LDL receptor double knock-out mice (Ldlr(-/-)xLcat(-/-) or DKO) spontaneously develop functioning ectopic brown adipose tissue (BAT) in skeletal muscle, putatively contributing to protection from the diet-induced obesity phenotype. Here we further investigated their developmental origin and the mechanistic role of LCAT deficiency. Gene profiling of skeletal muscle in DKO newborns and adults revealed a classical lineage. Primary quiescent satellite cells (SC) from chow-fed DKO mice, not in Ldlr(-/-)xLcat(+/+) single-knock-out (SKO) or C57BL/6 wild type, were found to (i) express exclusively classical BAT-selective genes, (ii) be primed to express key functional BAT genes, and (iii) exhibit markedly increased ex vivo adipogenic differentiation into brown adipocytes. This gene priming effect was abrogated upon feeding the mice a 2% high cholesterol diet in association with accumulation of excess intracellular cholesterol. Ex vivo cholesterol loading of chow-fed DKO SC recapitulated the effect, indicating that cellular cholesterol is a key regulator of SC-to-BAT differentiation. Comparing adipogenicity of Ldlr(+/+)xLcat(-/-) (LCAT-KO) SC with DKO SC identified a role for LCAT deficiency in priming SC to express BAT genes. Additionally, we found that reduced cellular cholesterol is important for adipogenic differentiation, evidenced by increased induction of adipogenesis in cholesterol-depleted SC from both LCAT-KO and SKO mice. Taken together, we conclude that ectopic BAT in DKO mice is classical in origin, and its development begins in utero. We further showed complementary roles of LCAT deficiency and cellular cholesterol reduction in the SC-to-BAT adipogenesis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Targeting cancer using cholesterol conjugates

    PubMed Central

    Radwan, Awwad A.; Alanazi, Fares K.

    2013-01-01

    Conjugation of cholesterol moiety to active compounds for either cancer treatment or diagnosis is an attractive approach. Cholesterol derivatives are widely studied as cancer diagnostic agents and as anticancer derivatives either in vitro or in vivo using animal models. In largely growing studies, anticancer agents have been chemically conjugated to cholesterol molecules, to enhance their pharmacokinetic behavior, cellular uptake, target specificity, and safety. To efficiently deliver anticancer agents to the target cells and tissues, many different cholesterol–anticancer conjugates were synthesized and characterized, and their anticancer efficiencies were tested in vitro and in vivo. PMID:24493968

  6. Cholesterol perturbs lipid bilayers nonuniversally.

    PubMed

    Pan, Jianjun; Mills, Thalia T; Tristram-Nagle, Stephanie; Nagle, John F

    2008-05-16

    Cholesterol is well known to modulate the physical properties of biomembranes. Using modern x-ray scattering methods, we have studied the effects of cholesterol on the bending modulus K(C), the thickness D(HH), and the orientational order parameter S(xray) of lipid bilayers. We find that the effects are different for at least three classes of phospholipids characterized by different numbers of saturated hydrocarbon chains. Most strikingly, cholesterol strongly increases K(C) when both chains of the phospholipid are fully saturated but not at all when there are two monounsaturated chains.

  7. Cholesterol Perturbs Lipid Bilayers Nonuniversally

    SciTech Connect

    Pan Jianjun; Mills, Thalia T.; Tristram-Nagle, Stephanie; Nagle, John F.

    2008-05-16

    Cholesterol is well known to modulate the physical properties of biomembranes. Using modern x-ray scattering methods, we have studied the effects of cholesterol on the bending modulus K{sub C}, the thickness D{sub HH}, and the orientational order parameter S{sub xray} of lipid bilayers. We find that the effects are different for at least three classes of phospholipids characterized by different numbers of saturated hydrocarbon chains. Most strikingly, cholesterol strongly increases K{sub C} when both chains of the phospholipid are fully saturated but not at all when there are two monounsaturated chains.

  8. Clinically used selective estrogen receptor modulators affect different steps of macrophage-specific reverse cholesterol transport

    PubMed Central

    Fernández-Suárez, María E.; Escolà-Gil, Joan C.; Pastor, Oscar; Dávalos, Alberto; Blanco-Vaca, Francisco; Lasunción, Miguel A.; Martínez-Botas, Javier; Gómez-Coronado, Diego

    2016-01-01

    Selective estrogen receptor modulators (SERMs) are widely prescribed drugs that alter cellular and whole-body cholesterol homeostasis. Here we evaluate the effect of SERMs on the macrophage-specific reverse cholesterol transport (M-RCT) pathway, which is mediated by HDL. Treatment of human and mouse macrophages with tamoxifen, raloxifene or toremifene induced the accumulation of cytoplasmic vesicles of acetyl-LDL-derived free cholesterol. The SERMs impaired cholesterol efflux to apolipoprotein A-I and HDL, and lowered ABCA1 and ABCG1 expression. These effects were not altered by the antiestrogen ICI 182,780 nor were they reproduced by 17β-estradiol. The treatment of mice with tamoxifen or raloxifene accelerated HDL-cholesteryl ester catabolism, thereby reducing HDL-cholesterol concentrations in serum. When [3H]cholesterol-loaded macrophages were injected into mice intraperitoneally, tamoxifen, but not raloxifene, decreased the [3H]cholesterol levels in serum, liver and feces. Both SERMs downregulated liver ABCG5 and ABCG8 protein expression, but tamoxifen reduced the capacity of HDL and plasma to promote macrophage cholesterol efflux to a greater extent than raloxifene. We conclude that SERMs interfere with intracellular cholesterol trafficking and efflux from macrophages. Tamoxifen, but not raloxifene, impair M-RCT in vivo. This effect is primarily attributable to the tamoxifen-mediated reduction of the capacity of HDL to promote cholesterol mobilization from macrophages. PMID:27601313

  9. Clinically used selective estrogen receptor modulators affect different steps of macrophage-specific reverse cholesterol transport.

    PubMed

    Fernández-Suárez, María E; Escolà-Gil, Joan C; Pastor, Oscar; Dávalos, Alberto; Blanco-Vaca, Francisco; Lasunción, Miguel A; Martínez-Botas, Javier; Gómez-Coronado, Diego

    2016-09-07

    Selective estrogen receptor modulators (SERMs) are widely prescribed drugs that alter cellular and whole-body cholesterol homeostasis. Here we evaluate the effect of SERMs on the macrophage-specific reverse cholesterol transport (M-RCT) pathway, which is mediated by HDL. Treatment of human and mouse macrophages with tamoxifen, raloxifene or toremifene induced the accumulation of cytoplasmic vesicles of acetyl-LDL-derived free cholesterol. The SERMs impaired cholesterol efflux to apolipoprotein A-I and HDL, and lowered ABCA1 and ABCG1 expression. These effects were not altered by the antiestrogen ICI 182,780 nor were they reproduced by 17β-estradiol. The treatment of mice with tamoxifen or raloxifene accelerated HDL-cholesteryl ester catabolism, thereby reducing HDL-cholesterol concentrations in serum. When [(3)H]cholesterol-loaded macrophages were injected into mice intraperitoneally, tamoxifen, but not raloxifene, decreased the [(3)H]cholesterol levels in serum, liver and feces. Both SERMs downregulated liver ABCG5 and ABCG8 protein expression, but tamoxifen reduced the capacity of HDL and plasma to promote macrophage cholesterol efflux to a greater extent than raloxifene. We conclude that SERMs interfere with intracellular cholesterol trafficking and efflux from macrophages. Tamoxifen, but not raloxifene, impair M-RCT in vivo. This effect is primarily attributable to the tamoxifen-mediated reduction of the capacity of HDL to promote cholesterol mobilization from macrophages.

  10. Cholesterol Inhibits M-type K+ Channels via Protein Kinase C-dependent Phosphorylation in Sympathetic Neurons*

    PubMed Central

    Lee, Seul-Yi; Choi, Hyun-Kyung; Kim, Seong-Tae; Chung, Sungkwon; Park, Myoung Kyu; Cho, Jung-Hwa; Ho, Won-Kyung; Cho, Hana

    2010-01-01

    M-type (KCNQ) potassium channels play an important role in regulating the action potential firing in neurons. Here, we investigated the effect of cholesterol on M current in superior cervical ganglion (SCG) sympathetic neurons, using the patch clamp technique. M current was inhibited in a dose-dependent manner by cholesterol loading with a methyl-β-cyclodextrin-cholesterol complex. This effect was prevented when membrane cholesterol level was restored by including empty methyl-β-cyclodextrin in the pipette solution. Dialysis of cells with AMP-PNP instead of ATP prevented cholesterol action on M currents. Protein kinase C (PKC) inhibitor, calphostin C, abolished cholesterol-induced inhibition whereas the PKC activator, PDBu, mimicked the inhibition of M currents by cholesterol. The in vitro kinase assay showed that KCNQ2 subunits of M channel can be phosphorylated by PKC. A KCNQ2 mutant that is defective in phosphorylation by PKC failed to show current inhibition not only by PDBu but also by cholesterol. These results indicate that cholesterol-induced inhibition of M currents is mediated by PKC phosphorylation. The inhibition of M currents by PDBu and cholesterol was completely blocked by PIP2 loading, indicating that the decrease in PIP2-channel interaction underlies M channel inhibition by PKC-mediated phosphorylation. We conclude that cholesterol specifically regulates M currents in SCG neurons via PKC activation. PMID:20123983

  11. Cholesterol's location in lipid bilayers

    SciTech Connect

    Marquardt, Drew; Kučerka, Norbert; Wassall, Stephen R.; Harroun, Thad A.; Katsaras, John

    2016-04-04

    It is well known that cholesterol modifies the physical properties of lipid bilayers. For example, the much studied liquid-ordered Lo phase contains rapidly diffusing lipids with their acyl chains in the all trans configuration, similar to gel phase bilayers. Moreover, the Lo phase is commonly associated with cholesterol-enriched lipid rafts, which are thought to serve as platforms for signaling proteins in the plasma membrane. Cholesterol's location in lipid bilayers has been studied extensively, and it has been shown – at least in some bilayers – to align differently from its canonical upright orientation, where its hydroxyl group is in the vicinity of the lipid–water interface. In this study we review recent works describing cholesterol's location in different model membrane systems with emphasis on results obtained from scattering, spectroscopic and molecular dynamics studies.

  12. Cholesterol's location in lipid bilayers

    DOE PAGES

    Marquardt, Drew; Kučerka, Norbert; Wassall, Stephen R.; ...

    2016-04-04

    It is well known that cholesterol modifies the physical properties of lipid bilayers. For example, the much studied liquid-ordered Lo phase contains rapidly diffusing lipids with their acyl chains in the all trans configuration, similar to gel phase bilayers. Moreover, the Lo phase is commonly associated with cholesterol-enriched lipid rafts, which are thought to serve as platforms for signaling proteins in the plasma membrane. Cholesterol's location in lipid bilayers has been studied extensively, and it has been shown – at least in some bilayers – to align differently from its canonical upright orientation, where its hydroxyl group is in themore » vicinity of the lipid–water interface. In this study we review recent works describing cholesterol's location in different model membrane systems with emphasis on results obtained from scattering, spectroscopic and molecular dynamics studies.« less

  13. Cholesterol confusion and statin controversy.

    PubMed

    DuBroff, Robert; de Lorgeril, Michel

    2015-07-26

    The role of blood cholesterol levels in coronary heart disease (CHD) and the true effect of cholesterol-lowering statin drugs are debatable. In particular, whether statins actually decrease cardiac mortality and increase life expectancy is controversial. Concurrently, the Mediterranean diet model has been shown to prolong life and reduce the risk of diabetes, cancer, and CHD. We herein review current data related to both statins and the Mediterranean diet. We conclude that the expectation that CHD could be prevented or eliminated by simply reducing cholesterol appears unfounded. On the contrary, we should acknowledge the inconsistencies of the cholesterol theory and recognize the proven benefits of a healthy lifestyle incorporating a Mediterranean diet to prevent CHD.

  14. Americans' Cholesterol Levels Keep Falling

    MedlinePlus

    ... and 2013-2014, the CDC reported. Dr. David Friedman is chief of heart failure services at Long ... for cholesterol treatment, all seem to be working," Friedman said. The study was published online Nov. 30 ...

  15. Formation of Cholesterol Bilayer Domains Precedes Formation of Cholesterol Crystals in Cholesterol/Dimyristoylphosphatidylcholine Membranes: EPR and DSC Studies

    PubMed Central

    Mainali, Laxman; Raguz, Marija; Subczynski, Witold K.

    2013-01-01

    Saturation-recovery EPR along with DSC were used to determine the cholesterol content at which pure cholesterol bilayer domains (CBDs) and cholesterol crystals begin to form in dimyristoylphosphatidylcholine (DMPC) membranes. To preserve compositional homogeneity throughout the membrane suspension, lipid multilamellar dispersions were prepared using a rapid solvent exchange method. The cholesterol content increased from 0 to 75 mol%. With spin-labeled cholesterol analogs it was shown that the CBDs begin to form at ~50 mol% cholesterol. It was confirmed by DSC that the cholesterol solubility threshold for DMPC membranes is detected at ~66 mol% cholesterol. At levels above this cholesterol content, monohydrate cholesterol crystals start to form. The major finding is that formation of CBDs precedes formation of cholesterol crystals. The region of the phase diagram for cholesterol contents between 50 and 66 mol% is described as a structured one-phase region in which CBDs have to be supported by the surrounding DMPC bilayer saturated with cholesterol. Thus, the phase boundary located at 66 mol% cholesterol separates the structured one-phase region (liquid-ordered phase of DMPC with CBDs) from the two-phase region where the structured liquid-ordered phase of DMPC coexists with cholesterol crystals. It is likely that CBDs are precursors of monohydrate cholesterol crystals. PMID:23834375

  16. Cholesterol and Benign Prostate Disease

    PubMed Central

    Freeman, Michael R.; Solomon, Keith R.

    2014-01-01

    The origins of benign prostatic diseases, such as benign prostatic hyperplasia (BPH) and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), are poorly understood. Patients suffering from benign prostatic symptoms report a substantially reduced quality of life, and the relationship between benign prostate conditions and prostate cancer is uncertain. Epidemiologic data for BPH and CP/CPPS are limited, however an apparent association bet ween BPH symptoms and cardiovascular disease (CVD) has been consistently reported. The prostate synthesizes and stores large amounts of cholesterol and prostate tissues may be particularly sensitive to perturbations in cholesterol metabolism. Hypercholesterolemi, a major risk factor for CVD, is also a risk factor for BPH. Animal model and clinical trial findings suggest that agents that inhibit cholesterol absorption from the intestine, such as the class of compounds known as polyene macrolides, can reduce prostate gland size and improve lower urinary tract symptoms (LUTS). Observational studies indicate that cholesterol-lowering drugs reduce the risk of aggressive prostate cancer, while prostate cancer cell growth and survival pathways depend in part on cholesterol-sensitive biochemical mechanisms. Here we review the evidence that cholesterol metabolism plays a role in the incidence of benign prostate disease and we highlight possible therapeutic approaches based on this concept. PMID:21862201

  17. Cholesterol and benign prostate disease.

    PubMed

    Freeman, Michael R; Solomon, Keith R

    2011-01-01

    The origins of benign prostatic diseases, such as benign prostatic hyperplasia (BPH) and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), are poorly understood. Patients suffering from benign prostatic symptoms report a substantially reduced quality of life, and the relationship between benign prostate conditions and prostate cancer is uncertain. Epidemiologic data for BPH and CP/CPPS are limited, however an apparent association between BPH symptoms and cardiovascular disease (CVD) has been consistently reported. The prostate synthesizes and stores large amounts of cholesterol and prostate tissues may be particularly sensitive to perturbations in cholesterol metabolism. Hypercholesterolemia, a major risk factor for CVD, is also a risk factor for BPH. Animal model and clinical trial findings suggest that agents that inhibit cholesterol absorption from the intestine, such as the class of compounds known as polyene macrolides, can reduce prostate gland size and improve lower urinary tract symptoms (LUTS). Observational studies indicate that cholesterol-lowering drugs reduce the risk of aggressive prostate cancer, while prostate cancer cell growth and survival pathways depend in part on cholesterol-sensitive biochemical mechanisms. Here we review the evidence that cholesterol metabolism plays a role in the incidence of benign prostate disease and we highlight possible therapeutic approaches based on this concept.

  18. Identification of Neutral Cholesterol Ester Hydrolase, a Key Enzyme Removing Cholesterol from Macrophages*S⃞

    PubMed Central

    Okazaki, Hiroaki; Igarashi, Masaki; Nishi, Makiko; Sekiya, Motohiro; Tajima, Makiko; Takase, Satoru; Takanashi, Mikio; Ohta, Keisuke; Tamura, Yoshiaki; Okazaki, Sachiko; Yahagi, Naoya; Ohashi, Ken; Amemiya-Kudo, Michiyo; Nakagawa, Yoshimi; Nagai, Ryozo; Kadowaki, Takashi; Osuga, Jun-ichi; Ishibashi, Shun

    2008-01-01

    Unstable lipid-rich plaques in atherosclerosis are characterized by the accumulation of macrophage foam cells loaded with cholesterol ester (CE). Although hormone-sensitive lipase and cholesteryl ester hydrolase (CEH) have been proposed to mediate the hydrolysis of CE in macrophages, circumstantial evidence suggests the presence of other enzymes with neutral cholesterol ester hydrolase (nCEH) activity. Here we show that the murine orthologue of KIAA1363, designated as neutral cholesterol ester hydrolase (NCEH), is a microsomal nCEH with high expression in murine and human macrophages. The effect of various concentrations of NaCl on its nCEH activity resembles that on endogenous nCEH activity of macrophages. RNA silencing of NCEH decreases nCEH activity at least by 50%; conversely, its overexpression inhibits the CE formation in macrophages. Immunohistochemistry reveals that NCEH is expressed in macrophage foam cells in atherosclerotic lesions. These data indicate that NCEH is responsible for a major part of nCEH activity in macrophages and may be a potential therapeutic target for the prevention of atherosclerosis. PMID:18782767

  19. Excess cholesterol induces mouse egg activation and may cause female infertility

    PubMed Central

    Yesilaltay, Ayce; Dokshin, Gregoriy A.; Busso, Dolores; Wang, Li; Galiani, Dalia; Chavarria, Tony; Vasile, Eliza; Quilaqueo, Linda; Orellana, Juan Andrés; Walzer, Dalia; Shalgi, Ruth; Dekel, Nava; Albertini, David F.; Rigotti, Attilio; Page, David C.; Krieger, Monty

    2014-01-01

    The HDL receptor scavenger receptor, class B type I (SR-BI) controls the structure and fate of plasma HDL. Female SR-BI KO mice are infertile, apparently because of their abnormal cholesterol-enriched HDL particles. We examined the growth and meiotic progression of SR-BI KO oocytes and found that they underwent normal germinal vesicle breakdown; however, SR-BI KO eggs, which had accumulated excess cholesterol in vivo, spontaneously activated, and they escaped metaphase II (MII) arrest and progressed to pronuclear, MIII, and anaphase/telophase III stages. Eggs from fertile WT mice were activated when loaded in vitro with excess cholesterol by a cholesterol/methyl-β-cyclodextrin complex, phenocopying SR-BI KO oocytes. In vitro cholesterol loading of eggs induced reduction in maturation promoting factor and MAPK activities, elevation of intracellular calcium, extrusion of a second polar body, and progression to meiotic stages beyond MII. These results suggest that the infertility of SR-BI KO females is caused, at least in part, by excess cholesterol in eggs inducing premature activation and that cholesterol can activate WT mouse eggs to escape from MII arrest. Analysis of SR-BI KO female infertility raises the possibility that abnormalities in cholesterol metabolism might underlie some cases of human female infertility of unknown etiology. PMID:25368174

  20. Facts about...Blood Cholesterol. Revised.

    ERIC Educational Resources Information Center

    National Heart, Lung, and Blood Inst. (DHHS/NIH), Bethesda, MD.

    This fact sheet on blood cholesterol examines the connection between cholesterol and heart disease, lists risk factors for heart disease that can and cannot be controlled, points out who can benefit from lowering blood cholesterol, distinguishes between blood and dietary cholesterol, describes low density lipoprotein and high density lipoprotein…

  1. Niacin to Boost Your HDL "Good" Cholesterol

    MedlinePlus

    Niacin can boost 'good' cholesterol Niacin is a B vitamin that may raise your HDL ("good") cholesterol. But side effects might outweigh benefits for most ... been used to increase high-density lipoprotein (HDL) cholesterol — the "good" cholesterol that helps remove low-density ...

  2. Cholesterol-Modified Amino-Pullulan Nanoparticles as a Drug Carrier: Comparative Study of Cholesterol-Modified Carboxyethyl Pullulan and Pullulan Nanoparticles

    PubMed Central

    Tao, Xiaojun; Xie, Yongchao; Zhang, Qiufang; Qiu, Ximin; Yuan, Liming; Wen, Yi; Li, Min; Yang, Xiaoping; Tao, Ting; Xie, Minghui; Lv, Yanwei; Wang, Qinyi; Feng, Xing

    2016-01-01

    To search for nano-drug preparations with high efficiency in tumor treatment, we evaluated the drug-loading capacity and cell-uptake toxicity of three kinds of nanoparticles (NPs). Pullulan was grafted with ethylenediamine and hydrophobic groups to form hydrophobic cholesterol-modified amino-pullulan (CHAP) conjugates. Fourier transform infrared spectroscopy and nuclear magnetic resonance were used to identify the CHAP structure and calculate the degree of substitution of the cholesterol group. We compared three types of NPs with close cholesterol hydrophobic properties: CHAP, cholesterol-modified pullulan (CHP), and cholesterol-modified carboxylethylpullulan (CHCP), with the degree of substitution of cholesterol of 2.92%, 3.11%, and 3.46%, respectively. As compared with the two other NPs, CHAP NPs were larger, 263.9 nm, and had a positive surface charge of 7.22 mV by dynamic light-scattering measurement. CHAP NPs showed low drug-loading capacity, 12.3%, and encapsulation efficiency of 70.8%, which depended on NP hydrophobicity and was affected by surface charge. The drug release amounts of all NPs increased in the acid media, with CHAP NPs showing drug-release sensitivity with acid change. Cytotoxicity of HeLa cells was highest with mitoxantrone-loaded CHAP NPs on MTT assay. CHAP NPs may have potential as a high-efficiency drug carrier for tumor treatment. PMID:28335293

  3. Amperometric determination of serum total cholesterol with nanoparticles of cholesterol esterase and cholesterol oxidase.

    PubMed

    Aggarwal, V; Malik, J; Prashant, A; Jaiwal, P K; Pundir, C S

    2016-05-01

    We describe the preparation of glutaraldehyde cross-linked and functionalized cholesterol esterase nanoparticles (ChENPs) and cholesterol oxidase nanoparticles (ChOxNPs) aggregates and their co-immobilization onto Au electrode for improved amperometric determination of serum total cholesterol. Transmission electron microscope (TEM) images of ChENPs and ChOxNPs showed their spherical shape and average size of 35.40 and 56.97 nm, respectively. Scanning electron microscope (SEM) studies of Au electrode confirmed the co-immobilization of enzyme nanoparticles (ENPs). The biosensor exhibited optimal response at pH 5.5 and 40°C within 5 s when polarized at +0.25 V versus Ag/AgCl. The working/linear range of the biosensor was 10-700 mg/dl for cholesterol. The sensor showed high sensitivity and measured total cholesterol as low as 0.1 mg/dl. The biosensor was evaluated and employed for total cholesterol determination in sera of apparently healthy and diseased persons. The analytical recovery of added cholesterol was 90%, whereas the within-batch and between-batch coefficients of variation (CVs) were less than 2% and less than 3%. There was a good correlation (r = 0.99) between serum cholesterol values as measured by the standard enzymic colorimetric method and the current method. The initial activity of ENPs/working electrode was reduced by 50% during its regular use (200 times) over a period of 60 days when stored dry at 4°C.

  4. Cholesterol-based tethers and markers for model membranes investigation.

    PubMed

    Eicher-Lorka, O; Charkova, T; Matijoška, A; Kuodis, Z; Urbelis, G; Penkauskas, T; Mickevičius, M; Bulovas, A; Valinčius, G

    2016-02-01

    A series of new bifunctional cholesterol compounds for tethered bilayer membrane (tBLM) systems were synthesized and tested. The compounds containing cyclic disulfide group may be used as molecular anchors for phospholipid bilayers. Anchoring occurs through the insertion of the cholesterol moiety into the hydrophobic slab of the phospholipid layer, while the surface density of anchor molecules may be adjusted using disulfides terminated spacers. Five ethylene oxide segments between the disulfide group and the cholesteryl provide hydration of the layer separating solid support and model membrane. Another group of cholesterol derivatives described in this work contains either fluorescence probe or electroactive functional groups. We demonstrated the practical utility of these compounds for visualization of cholesterol extraction from and loading to tBLMs. We demonstrated that electroactive group containing cholesterol derivatives can be reconstituted either into vesicles or tBLMs. In both cases an electrochemical signal can be generated on electrodes from these probes. In general, the newly synthesized compound may be utilized in a variety of applications involving tethered bilayer systems and vesicles.

  5. A rapid gel electrophoretic chip for serum cholesterol determination.

    PubMed

    Kaminikado, Kenta; Ikeda, Ryuzo; Idegami, Koutaro; Nagatani, Naoki; Vestergaard, Mun'delanji C; Saito, Masato; Tamiya, Eiichi

    2011-05-07

    We present a rapid gel electrophoretic chip, composed of 2.5% (w/v) acrylamide and 1% (w/v) agarose gel, for serum cholesterol determination using a photo lithography technique. After optimizations, we determined the lipoprotein concentration of standard serum using a conventional enzyme method. The serum was diluted, stained and loaded for 15 min onto the chip. After loading, the intensities of low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) bands separated at the chip were estimated using an image analyzer. The intensities of these bands corresponded to concentrations obtained from a standard enzyme-based method. The detected LDL-C and HDL-C concentrations were linear up to 146 mg dL(-1) and 53 mg dL(-1) respectively. Finally, we carried out the cholesterol analysis using real biological samples obtained from nine volunteers using our electrophoretic chip. The LDL-C and HDL-C levels detected using our chip correlated well with the results obtained using the conventional enzyme-based method r(2) = 0.98 and r(2) = 0.86 for LDL-C and HDL-C, respectively. Although our sample size is small and confined only to health volunteers, we have demonstrated that this proof-of-concept gel electrophoretic chip can determine lipoproteins, simultaneously.

  6. Effect of Cholesterol on the Stability and Lubrication Efficiency of Phosphatidylcholine Surface Layers.

    PubMed

    Sorkin, Raya; Kampf, Nir; Klein, Jacob

    2017-08-01

    The lubrication properties of saturated PC lipid vesicles containing high cholesterol content under high loads were examined by detailed surface force balance measurements of normal and shear forces between two surface-attached lipid layers. Forces between two opposing mica surfaces bearing distearoylphosphatidylcholine (PC) (DSPC) small unilamellar vesicles (SUVs, or liposomes), or bilayers, with varying cholesterol content were measured across water, whereas dimyristoyl PC (DMPC), dipalmitoyl PC (DPPC), and DSPC SUVs containing 40% cholesterol were measured across liposome dispersions of SUVs of the same lipid composition as in the adsorbed layers. The results clearly demonstrate decreased stability and resistance to normal load with the increase in cholesterol content of DSPC SUVs. Friction coefficients between two 10% cholesterol PC-bilayers were in the same range as for 40% cholesterol bilayers (μ ≈ 10(-3)), indicating that cholesterol has a more substantial effect on the mechanical properties of a bilayer than on its lubrication performance. We further find that the lubrication efficiency of DMPC and DPPC with 40% cholesterol is superior to that of DSPC 40% cholesterol, most likely because of enhanced hydration-lubrication in these systems. We previously found that when experiments are performed in the presence of a lipid reservoir, layers can self-heal and therefore their robustness is less important under such conditions. We conclude that the effect of cholesterol in decreasing the stability is more pronounced than its effect on hydration, but the stability is, in turn, less important when a lipid reservoir is present. This study complements our previous work and sheds light on the effect of cholesterol, a prominent and important physiological lipid, on the mechanical and lubrication properties of gel-phase lipid layers.

  7. Statins increase hepatic cholesterol synthesis and stimulate fecal cholesterol elimination in mice.

    PubMed

    Schonewille, Marleen; de Boer, Jan Freark; Mele, Laura; Wolters, Henk; Bloks, Vincent W; Wolters, Justina C; Kuivenhoven, Jan A; Tietge, Uwe J F; Brufau, Gemma; Groen, Albert K

    2016-08-01

    Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis. Statins reduce plasma cholesterol levels, but whether this is actually caused by inhibition of de novo cholesterol synthesis has not been clearly established. Using three different statins, we investigated the effects on cholesterol metabolism in mice in detail. Surprisingly, direct measurement of whole body cholesterol synthesis revealed that cholesterol synthesis was robustly increased in statin-treated mice. Measurement of organ-specific cholesterol synthesis demonstrated that the liver is predominantly responsible for the increase in cholesterol synthesis. Excess synthesized cholesterol did not accumulate in the plasma, as plasma cholesterol decreased. However, statin treatment led to an increase in cholesterol removal via the feces. Interestingly, enhanced cholesterol excretion in response to rosuvastatin and lovastatin treatment was mainly mediated via biliary cholesterol secretion, whereas atorvastatin mainly stimulated cholesterol removal via the transintestinal cholesterol excretion pathway. Moreover, we show that plasma cholesterol precursor levels do not reflect cholesterol synthesis rates during statin treatment in mice. In conclusion, cholesterol synthesis is paradoxically increased upon statin treatment in mice. However, statins potently stimulate the excretion of cholesterol from the body, which sheds new light on possible mechanisms underlying the cholesterol-lowering effects of statins. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.

  8. Membrane cholesterol selectively modulates the activity of the human ABCG2 multidrug transporter.

    PubMed

    Telbisz, Agnes; Müller, Marianna; Ozvegy-Laczka, Csilla; Homolya, László; Szente, Lajos; Váradi, András; Sarkadi, Balázs

    2007-11-01

    The human ABCG2 multidrug transporter provides protection against numerous toxic compounds and causes multidrug resistance in cancer. Here we examined the effects of changes in membrane cholesterol on the function of this protein. Human ABCG2 was expressed in mammalian and in Sf9 insect cells, and membrane cholesterol depletion or enrichment was achieved by preincubation with beta cyclodextrin or its cholesterol-loaded form. We found that mild cholesterol depletion of intact mammalian cells inhibited ABCG2-dependent dye and drug extrusion in a reversible fashion, while the membrane localization of the transporter protein was unchanged. Cholesterol enrichment of cholesterol-poor Sf9 cell membrane vesicles greatly increased ABCG2-driven substrate uptake, substrate-stimulated ATPase activity, as well as the formation of a catalytic cycle intermediate (nucleotide trapping). Interestingly, modulation of membrane cholesterol did not significantly affect the function of the R482G or R482T substrate mutant ABCG2 variants, or that of the MDR1 transporter. The selective, major effect of membrane cholesterol on the wild-type ABCG2 suggests a regulation of the activity of this multidrug transporter during processing or in membrane micro-domain interactions. The experimental recognition of physiological and pharmacological substrates of ABCG2, as well as the fight against cancer multidrug resistance may be facilitated by demonstrating the key role of membrane cholesterol in this transport activity.

  9. [Accuracy of HDL cholesterol measurements].

    PubMed

    Niedmann, P D; Luthe, H; Wieland, H; Schaper, G; Seidel, D

    1983-02-01

    The widespread use of different methods for the determination of HDL-cholesterol (in Europe: sodium phosphotungstic acid/MgCl2) in connection with enzymatic procedures (in the USA: heparin/MnCl2 followed by the Liebermann-Burchard method) but common reference values makes it necessary to evaluate not only accuracy, specificity, and precision of the precipitation step but also of the subsequent cholesterol determination. A high ratio of serum vs. concentrated precipitation reagent (10:1 V/V) leads to the formation of variable amounts of delta-3.5-cholestadiene. This substance is not recognized by cholesterol oxidase but leads to an 1.6 times overestimation by the Liebermann-Burchard method. Therefore, errors in HDL-cholesterol determination should be considered and differences up to 30% may occur between HDL-cholesterol values determined by the different techniques (heparin/MnCl2 - Liebermann-Burchard and NaPW/MgCl2-CHOD-PAP).

  10. [Determination of HDL-cholesterol].

    PubMed

    Herrmann, W; Schütz, C; Reuter, W

    1983-01-01

    For the clinical practice methods of the determination of HDL-cholesterol made their way which are based on the precipitation of apolipoprotein-B-containing lipoproteins and a determination of cholesterol following. The expensive methods of the ultracentrifugation serve as reference methods. The most-spread precipitation techniques (heparin/MCl2, dextran sulphate/CaCl2 or MgCl2 photungstic acid/MgCl2) are comparatively observed with regard to their effectiveness, practicability and methodical and technical conditions (influence of the concentration of the precipitation reagents, pH-value, temperature, incubation and centrifugation conditions). Results of own investigations as well as data from literature are presented to the problem of the harmonization of the cholesterol determination with the precipitation technique. According to the opinion of the authors for the enzymatic determination of cholesterol by means of the CHOD-PAP-method the phosphotungstic acid precipitation well stood the test, whereas for the chemical determination of cholesterol after Liebermann-Burchard in manual or automatized works the precipitation by means of dextran sulphate/CaCl2 (40 g/l, 2.0 mol/l) is to be recommended. The superabundant precipitations with phosphotungstic acid and dextran sulphate/MgCl2 (20 g/l, 2.0 mol/l) achieve higher results in Liebermann-Burchard's reaction likely on account of interferences.

  11. RADIOAUTOGRAPHY OF CHOLESTEROL IN LUNG

    PubMed Central

    Darrah, Hilary K.; Hedley-Whyte, John; Hedley-Whyte, E. Tessa

    1971-01-01

    30 Swiss albino mice aged 8 days were injected intraperitoneally with 0.2 ml of a solution of 4% N,N-dimethyl-formamide in 5% dextrose in water containing cholesterol-1,2-3H (∼1 mCi/ml). Lung tissue was embedded in an Epon mixture after either acetone and propylene oxide dehydration, partial ethanol and Epon 812 dehydration, or the precipitation of cholesterol by digitonin succeeded by partial dehydration. The distribution of cholesterol-1,2-3H in lung parenchyma in 1µ Epon section radioautograms was compared with that in frozen section radioautograms and was found to be independent of the manner of tissue processing. Grain distribution in the tissue was essentially the same whether 16, 63, 93, or 100% radioactivity was retained in the lung. However, grain distribution in the alveolar spaces differed, presumably due to displacement of pulmonary surfactant, which contains cholesterol. Intracellular distribution of cholesterol, in electron microscope radioautograms, was the same with either 51% or 93% retention of radioactivity in the lung. Loss of radioactivity into the various processing solutions was monitored. The various processing techniques have different drawbacks. PMID:19866763

  12. Turnover of xanthoma cholesterol in hyperlipoproteinemia patients.

    PubMed

    Bhattacharyya, A K; Connor, W E; Mausolf, F A; Flatt, A D

    1976-03-01

    The turnover of xanthoma cholesterol was measured in 9 hyperlipidemic and one normocholesterolemic patients. Sequential biopsies of the xanthomas were obtained 13 to 364 days after the administration of isotopic cholesterol and were then analyzed for cholesterol specific activity. A total of 34 xanthomas of 3 different types - 10 tendon xanthomas, 3 tuberous xanthomas, and 21 xanthelasmas - comprised the material for analysis. The cholesterol specific activity ratio of tendron xanthomas to that of the plasma varied from 11 per cent at 21 days to a maximum of 543 per cent at 122 days after the intravenous administration of isotopic cholesterol. This ratio declined to 426 per cent at 182 days and was still 131 per cent at 364 days. Similarly, the cholesterol specific activity of xanthelasmas increased gradually. In most instances, the xanthelasma cholesterol attained isotopic equilibration with plasma cholesterol by about 50 days but varied from patient to patient (minimum time, 46 days and maximum time, 91 days). The cholesterol content of xanthomas ranged from 10.7 to 197.0 mg per gram of dry weight of the tissue. Sixty-one to 87 per cent of the total xanthoma cholesterol was esterified. No other sterols were identified in these xanthomas. Thus, the cholesterol of 3 types of xanthoma readily attained isotopic equilibration with the plasma cholesterol which suggested total exchangeability of cholesterol between plasma and xanthomas. The uptake of cholesterol by the xanthomas from plasma was rapid considering the large mass of cholesterol in the lesions. The turnover of xanthoma cholesterol was intermediate between that of the rapidly exchangeable pool and of the slowly exchangeable pool of body cholesterol. Comparison of these results with those obtained in human advanced atheroma suggest that the turnover of xanthoma cholesterol and atheroma cholesterol are quite different.

  13. Behavioral, biochemical and cellular correlates in the protective effect of sertraline against transient global ischemia induced behavioral despair: possible involvement of nitric oxide-cyclic guanosine monophosphate study pathway.

    PubMed

    Gaur, Vaibhav; Kumar, Anil

    2010-04-29

    Post-stroke depression (PSD) is one of the psychiatric complications after stroke. Present study was conducted to elucidate the protective effect of sertraline and possible involvement of nitric oxide mechanism against transient global ischemia induced behavioral despair. Bilateral common carotid artery occlusion was given twice for 5 min at 10 min interval followed by 96 h reperfusion. Ischemia reperfusion significantly increased immobility period and decreased resistance to lateral push as compared to sham-operated group. Ischemia reperfusion caused significant oxidative damage and mitochondrial enzyme complex (I-III) dysfunction as compared to sham group. Sertraline (5 and 10mg/kg) treatment significantly reduced immobility period, increased resistance to lateral push, attenuated oxidative damage and restored mitochondrial enzyme complex activities as compared to ischemia group. L-Arginine (100mg/kg) or sildenafil (5mg/kg) pretreatment with sertraline (5mg/kg) significantly reversed the protective effect of sertraline. However, L-NAME (10mg/kg) or 7NI (10mg/kg) pretreatment with sertraline (5mg/kg) significantly potentiated their protective effect which were significant as compared to their effect alone. The present study shows that nitric oxide modulation is involved in the protective effect of sertraline. Copyright 2010 Elsevier Inc. All rights reserved.

  14. Treating ram sperm with cholesterol-loaded cyclodextrins improves cryosurvival

    USDA-ARS?s Scientific Manuscript database

    Diluted ram sperm can be held for 24 h at 5º C prior to cryopreservation without impacting cryosurvival rates, however, the effects this storage has on subsequent fertility is unknown. These studies were conducted to evaluate the fertility of semen held for 24 h (to mimic shipping semen to a cryopr...

  15. Polarizable multipolar electrostatics for cholesterol

    NASA Astrophysics Data System (ADS)

    Fletcher, Timothy L.; Popelier, Paul L. A.

    2016-08-01

    FFLUX is a novel force field under development for biomolecular modelling, and is based on topological atoms and the machine learning method kriging. Successful kriging models have been obtained for realistic electrostatics of amino acids, small peptides, and some carbohydrates but here, for the first time, we construct kriging models for a sizeable ligand of great importance, which is cholesterol. Cholesterol's mean total (internal) electrostatic energy prediction error amounts to 3.9 kJ mol-1, which pleasingly falls below the threshold of 1 kcal mol-1 often cited for accurate biomolecular modelling. We present a detailed analysis of the error distributions.

  16. Effect of ezetimibe on plasma cholesterol levels, cholesterol absorption and secretion of biliary cholesterol in laboratory opossums with high and low responses to dietary cholesterol

    PubMed Central

    Chan, Jeannie; Kushwaha, Rampratap S.; VandeBerg, Jane F.; VandeBerg, John L.

    2008-01-01

    Partially inbred lines of laboratory opossums differ in plasma LDL cholesterol concentration and cholesterol absorption on a high cholesterol diet. The aim of the present studies was to determine whether ezetimibe inhibits cholesterol absorption and eliminates the differences in plasma cholesterol and hepatic cholesterol metabolism between high and low responders on a high cholesterol diet. Initially, we determined that the optimum dose of ezetimibe was 5 mg/kg/day, and treated six high and six low responding opossums with this dose (with equal numbers of controls) for 3 weeks while opossums consumed a high cholesterol and low fat (HCLF) diet. Plasma and LDL cholesterol concentrations decreased significantly (P<0.05) in treated but not in untreated high responding opossums. Plasma cholesterol concentrations of untreated low responders increased slightly (P<0.05) but not in treated low responders. Percent cholesterol absorption was significantly higher in untreated high responders than in other groups. Livers from high responders with or without treatment were significantly (P <0.01) heavier than livers from low responders with or without treatment. Hepatic cholesterol concentrations in untreated high responders were significantly (P<0.05) higher than in low responders with or without treatment (P<0.001). The gall bladder bile cholesterol concentrations in untreated high responders were significantly (P<0.05) lower than in other groups. A decrease in biliary cholesterol in low responders treated with ezetimibe was associated with a decrease in hepatic expression of ABCG5 and ABCG8. These studies suggest that ezetimibe decreases plasma cholesterol levels in high responders mainly by decreasing cholesterol absorption and increasing biliary cholesterol concentrations. Since ezetimibe’s target is NPC1L1 and NPC1L1 is expressed in the intestine of opossums, its effect on cholesterol absorption may be mediated by inhibiting NPC1L1 function in the intestine. PMID

  17. Effect of ezetimibe on plasma cholesterol levels, cholesterol absorption, and secretion of biliary cholesterol in laboratory opossums with high and low responses to dietary cholesterol.

    PubMed

    Chan, Jeannie; Kushwaha, Rampratap S; Vandeberg, Jane F; Vandeberg, John L

    2008-12-01

    Partially inbred lines of laboratory opossums differ in plasma low-density lipoprotein cholesterol concentration and cholesterol absorption on a high-cholesterol diet. The aim of the present studies was to determine whether ezetimibe inhibits cholesterol absorption and eliminates the differences in plasma cholesterol and hepatic cholesterol metabolism between high and low responders on a high-cholesterol diet. Initially, we determined that the optimum dose of ezetimibe was 5 mg/(kg d) and treated 6 high- and 6 low-responding opossums with this dose (with equal numbers of controls) for 3 weeks while the opossums consumed a high-cholesterol and low-fat diet. Plasma and low-density lipoprotein cholesterol concentrations decreased significantly (P < .05) in treated but not in untreated high-responding opossums. Plasma cholesterol concentrations increased slightly (P < .05) in untreated low responders but not in treated low responders. The percentage of cholesterol absorption was significantly higher in untreated high responders than in other groups. Livers from high responders with or without treatment were significantly (P < .01) heavier than livers from low responders with or without treatment. Hepatic cholesterol concentrations in untreated high responders were significantly (P < .05) higher than those in low responders with or without treatment (P < .001). The gall bladder bile cholesterol concentrations in untreated high responders were significantly (P < .05) lower than those in other groups. A decrease in biliary cholesterol in low responders treated with ezetimibe was associated with a decrease in hepatic expression of ABCG5 and ABCG8. These studies suggest that ezetimibe decreases plasma cholesterol levels in high responders mainly by decreasing cholesterol absorption and increasing biliary cholesterol concentrations. Because ezetimibe's target is NPC1L1 and NPC1L1 is expressed in the intestine of opossums, its effect on cholesterol absorption may be mediated

  18. Dietary cholesterol supplementation to a plant-based diet suppresses the complete pathway of cholesterol synthesis and induces bile acid production in Atlantic salmon (Salmo salar L.).

    PubMed

    Kortner, Trond M; Björkhem, Ingemar; Krasnov, Aleksei; Timmerhaus, Gerrit; Krogdahl, Åshild

    2014-06-28

    Plants now supply more than 50 % of protein in Norwegian salmon aquafeeds. The inclusion of plant protein in aquafeeds may be associated with decreased lipid digestibility and cholesterol and bile salt levels, indicating that the replacement of fishmeal with plant protein could result in inadequate supplies of cholesterol in fish. A reduction in feed efficiency, fish growth and pathogen resistance is often observed in parallel to alterations in sterol metabolism. Previous studies have indicated that the negative effects induced by plant components can be attenuated when diets are supplemented with cholesterol. The present study evaluated the effects of dietary cholesterol supplementation (1·5 %) in Atlantic salmon fed a plant-based diet for 77 d. The weights of body, intestines and liver were recorded and blood, tissues, faeces, chyme and bile were sampled for the evaluation of effects on growth, nutrient utilisation and metabolism, and transcriptome and metabolite levels, with particular emphasis on sterol metabolism and organ structure and function. Cholesterol supplementation did not affect the growth or organ weights of Atlantic salmon, but seemed to promote the induction of cholesterol and plant sterol efflux in the intestine while suppressing sterol uptake. Cholesterol biosynthesis decreased correspondingly and conversion into bile acids increased. The marked effect of cholesterol supplementation on bile acid synthesis suggests that dietary cholesterol can be used to increase bile acid synthesis in fish. The present study clearly demonstrated how Atlantic salmon adjusted their metabolic functions in response to the dietary load of cholesterol. It has also expanded our understanding of sterol metabolism and turnover, adding to the existing, rather sparse, knowledge of these processes in fish.

  19. Mechanical modeling of cholesterol crystallization in atherosclerotic plaques base on Micro-OCT images (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Luo, Yuemei; Liu, Xinyu; Chen, Si; Cui, Dongyao; Wang, Xianghong; Liu, Linbo

    2016-02-01

    Plaque rupture is the critical cause of cardiovascular thrombosis but this process is still under discussion. Recent studies show that, during crystallization, cholesterol crystals in atheromatous plaques accumulate rapidly in a limited space and may result in plaque rupture. However, the actual role of cholesterol crystals on plaque rupture remains unclear due to the lack of detailed morphological information of cholesterol crystals. In this study, we used a Micro-optical coherence tomography (µOCT) setup with 1-2 µm spatial resolution to extract the geometry of cholesterol crystals from human atherosclerotic artery ex vivo firstly. With measured dimensions of cholesterol crystals by this µOCT system (the average length and thickness of 269.1±80.16 µm and 3.0±0.33 µm), we developed a two-dimensional mechanical model in which rectangular shaped cholesterol crystals distribute at different locations spatially. We predicted the stress on the thin cap induced by the expansion of cholesterol crystals by use of finite-element method. Since a large portion of plaques (58%) rupture at points of peak circumferential stress (PCS), we used PCS as the primary indicator of plaque stability with blood pressure of 14.6 kPa on the lumen. The results demonstrate that loading of the concentrated crystals especially at the cap shoulder destabilize the plaque by proportionally increasing the PCS, while evenly distributed crystals loading along the cap might impose less PCS to the plaque than the concentrated case.

  20. Membrane Cholesterol Modulates Superwarfarin Toxicity

    SciTech Connect

    Marangoni, M. Natalia; Martynowycz, Michael W.; Kuzmenko, Ivan; Braun, David; Polak, Paul E.; Weinberg, Guy; Rubinstein, Israel; Gidalevitz, David; Feinstein, Douglas L.

    2016-04-26

    Superwarfarins are modified analogs of warfarin with additional lipophilic aromatic rings, up to 100-fold greater potency, and longer biological half-lives. We hypothesized that increased hydrophobicity allowed interactions with amphiphilic membranes and modulation of biological responses. We find that superwarfarins brodifacoum and difenacoum increase lactate production and cell death in neuroblastoma cells. In contrast, neither causes changes in glioma cells that have higher cholesterol content. After choleterol depletion, lactate production was increased and cell viability was reduced. Drug-membrane interactions were examined by surface X-ray scattering using Langmuir monolayers of dipalmitoylphosphatidylcholine and/or cholesterol. Specular X-ray reflectivity data revealed that superwarfarins, but not warfarin, intercalate between dipalmitoylphosphatidylcholine molecules, whereas grazing incidence X-ray diffraction demonstrated changes in lateral crystalline order of the film. Neither agent showed significant interactions with monolayers containing >20% cholesterol. These findings demonstrate an affinity of superwarfarins to biomembranes and suggest that cellular responses to these agents are regulated by cholesterol content.

  1. Community Guide to Cholesterol Resources.

    ERIC Educational Resources Information Center

    National Heart and Lung Inst. (DHHS/NIH), Bethesda, MD.

    This guide is divided into two sections, one for physicians and the other for patients. The physician section lists different resources including continuing medical education opportunities on the medical and scientific aspects of cholesterol and heart disease and on the physician's role in diagnosis and patient management. Additional materials on…

  2. Early steps in steroidogenesis: intracellular cholesterol trafficking

    PubMed Central

    Miller, Walter L.; Bose, Himangshu S.

    2011-01-01

    Steroid hormones are made from cholesterol, primarily derived from lipoproteins that enter cells via receptor-mediated endocytosis. In endo-lysosomes, cholesterol is released from cholesterol esters by lysosomal acid lipase (LAL; disordered in Wolman disease) and exported via Niemann-Pick type C (NPC) proteins (disordered in NPC disease). These diseases are characterized by accumulated cholesterol and cholesterol esters in most cell types. Mechanisms for trans-cytoplasmic cholesterol transport, membrane insertion, and retrieval from membranes are less clear. Cholesterol esters and “free” cholesterol are enzymatically interconverted in lipid droplets. Cholesterol transport to the cholesterol-poor outer mitochondrial membrane (OMM) appears to involve cholesterol transport proteins. Cytochrome P450scc (CYP11A1) then initiates steroidogenesis by converting cholesterol to pregnenolone on the inner mitochondrial membrane (IMM). Acute steroidogenic responses are regulated by cholesterol delivery from OMM to IMM, triggered by the steroidogenic acute regulatory protein (StAR). Chronic steroidogenic capacity is determined by CYP11A1 gene transcription. StAR mutations cause congenital lipoid adrenal hyperplasia, with absent steroidogenesis, potentially lethal salt loss, and 46,XY sex reversal. StAR mutations initially destroy most, but not all steroidogenesis; low levels of StAR-independent steroidogenesis are lost later due to cellular damage, explaining the clinical findings. Rare P450scc mutations cause a similar syndrome. This review addresses these early steps in steroid biosynthesis. PMID:21976778

  3. Remnant cholesterol and ischemic heart disease.

    PubMed

    Varbo, Anette; Nordestgaard, Børge G

    2014-08-01

    To review recent advances in the field of remnant cholesterol as a contributor to the development of ischemic heart disease (IHD). Epidemiologic, mechanistic, and genetic studies all support a role for elevated remnant cholesterol (=cholesterol in triglyceride-rich lipoproteins) as a contributor to the development of atherosclerosis and IHD. Observational studies show association between elevated remnant cholesterol and IHD, and mechanistic studies show remnant cholesterol accumulation in the arterial wall like LDL-cholesterol (LDL-C) accumulation. Furthermore, large genetic studies show evidence of remnant cholesterol as a causal risk factor for IHD independent of HDL-cholesterol levels. Genetic studies also show that elevated remnant cholesterol is associated with low-grade inflammation, whereas elevated LDL-C is not. There are several pharmacologic ways of lowering remnant cholesterol levels; however, it remains to be seen in large randomized clinical intervention trials if lowering of remnant cholesterol, in individuals with elevated levels, will reduce the risk of IHD. Evidence is emerging for elevated remnant cholesterol being a causal risk factor for IHD. Elevated remnant cholesterol levels likely are part of the explanation of the residual risk of IHD observed after LDL-C has been lowered to recommended levels.

  4. Cholesterol autoxidation in phospholipid membrane bilayers

    SciTech Connect

    Sevanian, A.; McLeod, L.L.

    1987-09-01

    Lipid peroxidation in unilamellar liposomes of known cholesterol-phospholipid composition was monitored under conditions of autoxidation or as induced by a superoxide radical generating system, gamma-irradiation or cumene hydroperoxide. Formation of cholesterol oxidation products was indexed to the level of lipid peroxidation. The major cholesterol oxidation products identified were 7-keto-cholesterol, isomeric cholesterol 5,6-epoxides, isomeric 7-hydroperoxides and isomeric 3,7-cholestane diols. Other commonly encountered products included 3,5-cholestadiene-7-one and cholestane-3 beta, 5 alpha, 6 beta-triol. Superoxide-dependent peroxidation required iron and produced a gradual increase in 7-keto-cholesterol and cholesterol epoxides. Cholesterol oxidation was greatest in liposomes containing high proportions of unsaturated phospholipid to cholesterol (4:1 molar ratio), intermediate with low phospholipid to cholesterol ratios (2:1) and least in liposomes prepared with dipalmitoylphosphatidylcholine and cholesterol. This relationship held regardless of the oxidizing conditions used. Cumene hydroperoxide-dependent lipid peroxidation and/or more prolonged oxidations with other oxidizing systems yielded a variety of products where cholesterol-5 beta,6 beta-epoxide, 7-ketocholesterol and the 7-hydroperoxides were most consistently elevated. Oxyradical initiation of lipid peroxidation produced a pattern of cholesterol oxidation products distinguishable from the pattern derived by cumene hydroperoxide-dependent peroxidation.

  5. Improved Coarse-Grained Modeling of Cholesterol-Containing Lipid Bilayers

    SciTech Connect

    Daily, Michael D.; Olsen, Brett N.; Schlesinger, Paul H.; Ory, Daniel S.; Baker, Nathan A.

    2014-03-24

    In mammalian cells cholesterol is essential for membrane function, but in excess can be cytototoxic. The cellular response to acute cholesterol loading involves biophysical-based mechanisms that regulate cholesterol levels, through modulation of the “activity” or accessibility of cholesterol to extra-membrane acceptors. Experiments and united atom (UA) simulations show that at high concentrations of cholesterol, lipid bilayers thin significantly and cholesterol availability to external acceptors increases substantially. Such cholesterol activation is critical to its trafficking within cells. Here we aim to reduce the computational cost to enable simulation of large and complex systems involved in cholesterol regulation, such as those including oxysterols and cholesterol-sensing proteins. To accomplish this, we have modified the published MARTINI coarse-grained force field to improve its predictions of cholesterol-induced changes in both macroscopic and microscopic properties of membranes. Most notably, MARTINI fails to capture both the (macroscopic) area condensation and membrane thickening seen at less than 30% cholesterol and the thinning seen above 40% cholesterol. The thinning at high concentration is critical to cholesterol activation. Microscopic properties of interest include cholesterol-cholesterol radial distribution functions (RDFs), tilt angle, and accessible surface area. First, we develop an “angle-corrected” model wherein we modify the coarse-grained bond angle potentials based on atomistic simulations. This modification significantly improves prediction of macroscopic properties, most notably the thickening/thinning behavior, and also slightly improves microscopic property prediction relative to MARTINI. Second, we add to the angle correction a “volume correction” by also adjusting phospholipid bond lengths to achieve a more accurate volume per molecule. The angle + volume correction substantially further improves the quantitative

  6. Sericin reduces serum cholesterol in rats and cholesterol uptake into Caco-2 cells.

    PubMed

    Limpeanchob, Nanteetip; Trisat, Kanittaporn; Duangjai, Acharaporn; Tiyaboonchai, Waree; Pongcharoen, Sutatip; Sutheerawattananonda, Manote

    2010-12-08

    A cholesterol lowering effect of sericin was investigated both in vivo and in vitro. Rats were dosed with cholesterol with and without sericin for 14 days. Non-high-density lipoprotein (HDL) and total serum cholesterols were reduced in rats fed high-cholesterol diet with all three tested doses of sericin (10, 100, and 1000 mg kg(-1) day(-1)). The potential mechanism of actions was determined by measuring the uptake of radiolabeled cholesterol into differentiated Caco-2 cells and cholesterol solubility in mixed lipid micelles. Concentration of sericin as low as 25 and 50 μg/mL inhibited 30% of cholesterol uptake into Caco-2 cells whereas no effect was found at higher concentration. Cholesterol micellar solubility was reduced in the presence of sericin. This study suggests the cholesterol lowering effect of sericin results from its inhibition of cholesterol absorption in intestinal cells and its reduction of cholesterol solubility in lipid micelles.

  7. ABCA3 protects alveolar epithelial cells against free cholesterol induced cell death.

    PubMed

    Zarbock, Ralf; Kaltenborn, Eva; Frixel, Sabrina; Wittmann, Thomas; Liebisch, Gerhard; Schmitz, Gerd; Griese, Matthias

    2015-07-01

    Diffuse parenchymal lung diseases (DPLDs) are characterized by chronic inflammation and fibrotic remodeling of the interstitial tissue. A small fraction of DPLD cases can be genetically defined by mutations in certain genes, with ABCA3 being the gene most commonly affected. However, the pathomechanisms underlying ABCA3-induced DPLD are far from clear. To investigate whether ABCA3 plays a role in cellular cholesterol homeostasis, phospholipids, free cholesterol, and cholesteryl esters were quantified in cells stably expressing ABCA3 using mass spectrometry. Cellular free cholesterol and lipid droplets were visualized by filipin or oil red staining, respectively. Expression of SREBP regulated genes was measured using qPCR. Cell viability was assessed using the XTT assay. We found that wild type ABCA3 reduces cellular free cholesterol levels, induces the SREBP pathway, and renders cells more resistant to loading with exogenous cholesterol. Moreover, ABCA3 mutations found in patients with DPLD interfere with this protective effect of ABCA3, resulting in free cholesterol induced cell death. We conclude that ABCA3 plays a previously unrecognized role in the regulation of cellular cholesterol levels. Accumulation of free cholesterol as a result of a loss of ABCA3 export function represents a novel pathomechanism in ABCA3-induced DPLD. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. New Cholesterol Fighting Meds Target Key Gene

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_165942.html New Cholesterol Fighting Meds Target Key Gene Two trials ... 25, 2017 THURSDAY, May 25, 2017 (HealthDay News) -- New gene-based therapies appear to significantly decrease cholesterol ...

  9. High Cholesterol: Medicines to Help You

    MedlinePlus

    ... Consumer Information by Audience For Women High Cholesterol--Medicines To Help You Share Tweet Linkedin Pin it ... Test to check your cholesterol (LDL-C) Combination Medicines Brand Name Generic Name Advicor Niacin and Lovastatin ...

  10. Do You Know Your Cholesterol Levels?

    MedlinePlus

    ... Selected Audiences Contact The Health Information Center Do You Know Your Cholesterol Levels? Print-friendly Version (PDF, ... Your Heart: Get Moving and Eat Smart Did you know that high blood cholesterol is a serious ...

  11. Healthy Dietary Fats Help Beat High Cholesterol

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_166625.html Healthy Dietary Fats Help Beat High Cholesterol Eating them can reduce ... and Human Services. More Health News on Cholesterol Dietary Fats Heart Diseases--Prevention Recent Health News Related MedlinePlus ...

  12. What You Need to Know about Cholesterol

    MedlinePlus

    ... 164304.html What You Need to Know About Cholesterol Heart expert explains the difference between good and ... 28, 2017 MONDAY, March 27, 2017 (HealthDay News) -- Cholesterol plays a vital role in your health, so ...

  13. Active membrane cholesterol as a physiological effector.

    PubMed

    Lange, Yvonne; Steck, Theodore L

    2016-09-01

    Sterols associate preferentially with plasma membrane sphingolipids and saturated phospholipids to form stoichiometric complexes. Cholesterol in molar excess of the capacity of these polar bilayer lipids has a high accessibility and fugacity; we call this fraction active cholesterol. This review first considers how active cholesterol serves as an upstream regulator of cellular sterol homeostasis. The mechanism appears to utilize the redistribution of active cholesterol down its diffusional gradient to the endoplasmic reticulum and mitochondria, where it binds multiple effectors and directs their feedback activity. We have also reviewed a broad literature in search of a role for active cholesterol (as opposed to bulk cholesterol or lipid domains such as rafts) in the activity of diverse membrane proteins. Several systems provide such evidence, implicating, in particular, caveolin-1, various kinds of ABC-type cholesterol transporters, solute transporters, receptors and ion channels. We suggest that this larger role for active cholesterol warrants close attention and can be tested easily.

  14. Poly(amidoamine)-Cholesterol Conjugate Nanoparticles Obtained by Electrospraying as Novel Tamoxifen Delivery System

    PubMed Central

    Cavalli, R.; Bisazza, A.; Bussano, R.; Trotta, M.; Civra, A.; Lembo, D.; Ranucci, E.; Ferruti, P.

    2011-01-01

    A new poly(amidoamine)-cholesterol (PAA-cholesterol) conjugate was synthesized, characterized and used to produce nanoparticles by the electrospraying technique. The electrospraying is a method of liquid atomization that consists in the dispersion of a solution into small charged droplets by an electric field. Tuning the electrospraying process parameters spherical PAA-chol nanoparticles formed. The PAA-cholesterol nanoparticles showed sizes lower than 500 nm and spherical shape. The drug incorporation capacity was investigated using tamoxifen, a lipophilic anticancer drug, as model drug. The incorporation of the tamoxifen did not affect the shape and sizes of nanoparticles showing a drug loading of 40%. Tamoxifen-loaded nanoparticles exhibited a higher dose-dependent cytotoxicity than free tamoxifen, while blank nanoparticles did not show any cytotoxic effect at the same concentrations. The electrospray technique might be proposed to produce tamoxifen-loaded PAA-chol nanoparticle in powder form without any excipient in a single step. PMID:21785731

  15. Poly(amidoamine)-Cholesterol Conjugate Nanoparticles Obtained by Electrospraying as Novel Tamoxifen Delivery System.

    PubMed

    Cavalli, R; Bisazza, A; Bussano, R; Trotta, M; Civra, A; Lembo, D; Ranucci, E; Ferruti, P

    2011-01-01

    A new poly(amidoamine)-cholesterol (PAA-cholesterol) conjugate was synthesized, characterized and used to produce nanoparticles by the electrospraying technique. The electrospraying is a method of liquid atomization that consists in the dispersion of a solution into small charged droplets by an electric field. Tuning the electrospraying process parameters spherical PAA-chol nanoparticles formed. The PAA-cholesterol nanoparticles showed sizes lower than 500 nm and spherical shape. The drug incorporation capacity was investigated using tamoxifen, a lipophilic anticancer drug, as model drug. The incorporation of the tamoxifen did not affect the shape and sizes of nanoparticles showing a drug loading of 40%. Tamoxifen-loaded nanoparticles exhibited a higher dose-dependent cytotoxicity than free tamoxifen, while blank nanoparticles did not show any cytotoxic effect at the same concentrations. The electrospray technique might be proposed to produce tamoxifen-loaded PAA-chol nanoparticle in powder form without any excipient in a single step.

  16. Effect of cholesterol supplementation on cryosurvival of goat spermatozoa

    PubMed Central

    Behera, Sunita; Harshan, Hiron M.; Bhai, K. Lekshmi; Ghosh, K. N. Aravinda

    2015-01-01

    Aim: Sperm membrane cholesterol influences cryodamage during cryopreservation. The present study was carried out to evaluate the effect of varying cholesterol levels in Tris based extenders on the freezability of sexually healthy Malabari buck semen. Materials and Methods: A total of 48 ejaculates from two adults healthy sexually healthy Malabari bucks were utilized for the study. The collected and pooled ejaculates were divided into four groups with Group I serving as Control - I, Group II and III were treated with 1 mg and 2 mg of cholesterol-loaded-cyclodextrin (CLC)/120 × 106 spermatozoa, respectively, and Group IV, treated with 1 mg methyl-β-cyclodextrin (MβCD) served as Control - II. Manual freezing was carried out to cryopreserve the treated and control spermatozoa. Results: Treatment of semen samples with CLC resulted in improved maintenance of sperm motility at pre-freeze and post-thaw stages of cryopreservation without affecting hypo-osmotic swelling response. Treatment of semen with 1 mg of CLC/120 × 106 spermatozoa was observed to be better than treatment with 2 mg of CLC/120 × 106 spermatozoa. In general, MβCD treatment was found to result in significantly lower sperm characteristics than those of Control - I and CLC treatment at pre-feeze and post-thaw stages and when incubated up to 4 h. Conclusion: Cholesterol treatment of sexually healthy Malabari buck semen was found to hold promise for improving cryopreservability of spermatozoa. PMID:27047048

  17. Quercetin regulates hepatic cholesterol metabolism by promoting cholesterol-to-bile acid conversion and cholesterol efflux in rats.

    PubMed

    Zhang, Min; Xie, Zongkai; Gao, Weina; Pu, Lingling; Wei, Jingyu; Guo, Changjiang

    2016-03-01

    Quercetin, a common member of the flavonoid family, is widely present in plant kingdom. Despite that quercetin is implicated in regulating cholesterol metabolism, the molecular mechanism is poorly understood. We hypothesized that quercetin regulates cholesterol homeostasis through regulating the key enzymes involved in hepatic cholesterol metabolism. To test this hypothesis, we compared the profile of key enzymes and transcription factors involved in the hepatic cholesterol metabolism in rats with or without quercetin supplementation. Twenty male Wistar rats were randomly divided into control and quercetin-supplemented groups. Serum total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and total bile acids in feces and bile were measured. Hepatic enzymatic activities were determined by activity assay kit and high-performance liquid chromatography-based analyses. The messenger RNA (mRNA) and protein expressions were determined by reverse transcriptase polymerase chain reaction and Western blot analyses, respectively. The results showed that the activity of hepatic cholesterol 7α-hydroxylase, a critical enzyme in the conversion of cholesterol to bile acids, was significantly elevated by quercetin. The expression of cholesterol 7α-hydroxylase, as well as liver X receptor α, an important transcription factor, was also increased at both mRNA and protein levels by quercetin. However, quercetin exposure had no impact on the activity of hepatic HMG-CoA reductase, a rate-limiting enzyme in the biosynthesis of cholesterol. We also found that quercetin treatment significantly increased ATP binding cassette transporter G1 mRNA and protein expression in the liver, suggesting that quercetin may increase hepatic cholesterol efflux. Collectively, the results presented here indicate that quercetin regulates hepatic cholesterol metabolism mainly through the pathways that promote cholesterol-to-bile acid conversion and

  18. HDL functionality in reverse cholesterol transport--Challenges in translating data emerging from mouse models to human disease.

    PubMed

    Lee-Rueckert, Miriam; Escola-Gil, Joan Carles; Kovanen, Petri T

    2016-07-01

    Whereas LDL-derived cholesterol accumulates in atherosclerotic lesions, HDL particles are thought to facilitate removal of cholesterol from the lesions back to the liver thereby promoting its fecal excretion from the body. Because generation of cholesterol-loaded macrophages is inherent to atherogenesis, studies on the mechanisms stimulating the release of cholesterol from these cells and its ultimate excretion into feces are crucial to learn how to prevent lesion development or even induce lesion regression. Modulation of this key anti-atherogenic pathway, known as the macrophage-specific reverse cholesterol transport, has been extensively studied in several mouse models with the ultimate aim of applying the emerging knowledge to humans. The present review provides a detailed comparison and critical analysis of the various steps of reverse cholesterol transport in mouse and man. We attempt to translate this in vivo complex scenario into practical concepts, which could serve as valuable tools when developing novel HDL-targeted therapies.

  19. Non-cholesterol sterols and cholesterol metabolism in sitosterolemia.

    PubMed

    Othman, Rgia A; Myrie, Semone B; Jones, Peter J H

    2013-12-01

    Sitosterolemia (STSL) is a rare autosomal recessive disease, manifested by extremely elevated plant sterols (PS) in plasma and tissue, leading to xanthoma and premature atherosclerotic disease. Therapeutic approaches include limiting PS intake, interrupting enterohepatic circulation of bile acid using bile acid binding resins such as cholestyramine, and/or ileal bypass, and inhibiting intestinal sterol absorption by ezetimibe (EZE). The objective of this review is to evaluate sterol metabolism in STSL and the impact of the currently available treatments on sterol trafficking in this disease. The role of PS in initiation of xanthomas and premature atherosclerosis is also discussed. Blocking sterols absorption with EZE has revolutionized STSL patient treatment as it reduces circulating levels of non-cholesterol sterols in STSL. However, none of the available treatments including EZE have normalized plasma PS concentrations. Future studies are needed to: (i) explore where cholesterol and non-cholesterol sterols accumulate, (ii) assess to what extent these sterols in tissues can be mobilized after blocking their absorption, and (iii) define the factors governing sterol flux. Copyright © 2013. Published by Elsevier Ireland Ltd.

  20. Transfer of cholesterol by the NPC team.

    PubMed

    Vance, Jean E

    2010-08-04

    The mechanisms of intracellular cholesterol transport are largely unknown. In this issue of Cell Metabolism, Wang et al. (2010) identify amino acid residues on the lumenal lysosomal protein Niemann-Pick C2 (NPC2) that are required for intralysosomal transfer of endocytosed cholesterol to membrane-bound NPC1 via a process that avoids movement of hydrophobic cholesterol through the aqueous phase.

  1. Isolation of Cholesterol from an Egg Yolk

    ERIC Educational Resources Information Center

    Taber, Douglass F.; Li, Rui; Anson, Cory M.

    2011-01-01

    A simple procedure for the isolation of the cholesterol, by hydrolysis and extraction followed by column chromatography, is described. The cholesterol can be further purified by complexation with oxalic acid. It can also be oxidized and conjugated to cholestenone. The source of the cholesterol is one egg yolk, which contains about 200 mg of…

  2. Isolation of Cholesterol from an Egg Yolk

    ERIC Educational Resources Information Center

    Taber, Douglass F.; Li, Rui; Anson, Cory M.

    2011-01-01

    A simple procedure for the isolation of the cholesterol, by hydrolysis and extraction followed by column chromatography, is described. The cholesterol can be further purified by complexation with oxalic acid. It can also be oxidized and conjugated to cholestenone. The source of the cholesterol is one egg yolk, which contains about 200 mg of…

  3. Cholesterol Screening: A Practical Guide to Implementation.

    ERIC Educational Resources Information Center

    Kingery, Paul M.

    1995-01-01

    Dry-chemistry cholesterol analysis has made screening feasible in a variety of settings. The article provides practical tips for the implementation of mass cholesterol screening using a portable dry-chemistry analyzer and discusses issues involved in conducting effective cholesterol screening programs from start to finish. (SM)

  4. A sensitive assay for ABCA1-mediated cholesterol efflux using BODIPY -cholesterol

    USDA-ARS?s Scientific Manuscript database

    Studies have shown a negative association between cellular cholesterol efflux and coronary artery disease (CAD). Standard protocol for quantifying cholesterol efflux involves labeling cells with [(3)H]cholesterol and measuring release of the labeled sterol. Using [(3)H]cholesterol is not ideal for...

  5. Natural IgM and TLR Agonists Switch Murine Splenic Pan-B to “Regulatory” Cells That Suppress Ischemia-Induced Innate Inflammation via Regulating NKT-1 Cells

    PubMed Central

    Lobo, Peter I.; Schlegel, Kailo H.; Bajwa, Amandeep; Huang, Liping; Okusa, Mark D.

    2017-01-01

    Natural IgM anti-leukocyte autoantibodies (IgM-ALAs) inhibit inflammation by several mechanisms. Here, we show that pan-B cells and bone marrow-derived dendritic cells (BMDCs) are switched to regulatory cells when pretreated ex vivo with IgM. B cells are also switched to regulatory cells when pretreated ex vivo with CpG but not with LPS. Pre-emptive infusion of such ex vivo induced regulatory cells protects C57BL/6 mice from ischemia-induced acute kidney injury (AKI) via regulation of in vivo NKT-1 cells, which normally amplify the innate inflammatory response to DAMPS released after reperfusion of the ischemic kidney. Such ex vivo induced regulatory pan-B cells and BMDC express low CD1d and inhibit inflammation by regulating in vivo NKT-1 in the context of low-lipid antigen presentation and by a mechanism that requires costimulatory molecules, CD1d, PDL1/PD1, and IL10. Second, LPS and CpG have opposite effects on induction of regulatory activity in BMDC and B cells. LPS enhances regulatory activity of IgM-pretreated BMDC but negates the IgM-induced regulatory activity in B cells, while CpG, with or without IgM pretreatment, induces regulatory activity in B cells but not in BMDC. Differences in the response of pan-B and dendritic cells to LPS and CpG, especially in the presence of IgM-ALA, may have relevance during infections and inflammatory disorders where there is an increased IgM-ALA and release of TLRs 4 and 9 ligands. Ex vivo induced regulatory pan-B cells could have therapeutic relevance as these easily available cells can be pre-emptively infused to prevent AKI that can occur during open heart surgery or in transplant recipients receiving deceased donor organs. PMID:28878768

  6. HIF-1α-mediated upregulation of SERCA2b: The endogenous mechanism for alleviating the ischemia-induced intracellular Ca(2+) store dysfunction in CA1 and CA3 hippocampal neurons.

    PubMed

    Kopach, Olga; Maistrenko, Anastasiia; Lushnikova, Iryna; Belan, Pavel; Skibo, Galina; Voitenko, Nana

    2016-05-01

    Pyramidal neurons of the hippocampus possess differential susceptibility to the ischemia-induced damage with the highest vulnerability of CA1 and the lower sensitivity of CA3 neurons. This damage is triggered by Ca(2+)-dependent excitotoxicity and can result in a delayed cell death that might be potentially suspended through activation of endogenous neuroprotection with the hypoxia-inducible transcription factors (HIF). However, the molecular mechanisms of this neuroprotection remain poorly understood. Here we show that prolonged (30min) oxygen and glucose deprivation (OGD) in situ impairs intracellular Ca(2+) regulation in CA1 rather than in CA3 neurons with the differently altered expression of genes coding Ca(2+)-ATPases: the mRNA level of plasmalemmal Ca(2+)-ATPases (PMCA1 and PMCA2 subtypes) was downregulated in CA1 neurons, whereas the mRNA level of the endoplasmic reticulum Ca(2+)-ATPases (SERCA2b subtype) was increased in CA3 neurons at 4h of re-oxygenation after prolonged OGD. These demonstrate distinct susceptibility of CA1 and CA3 neurons to the ischemic impairments in intracellular Ca(2+) regulation and Ca(2+)-ATPase expression. Stabilization of HIF-1α by inhibiting HIF-1α hydroxylation prevented the ischemic decrease in both PMCA1 and PMCA2 mRNAs in CA1 neurons, upregulated the SERCA2b mRNA level and eliminated the OGD-induced Ca(2+) store dysfunction in these neurons. Cumulatively, these findings reveal the previously unknown HIF-1α-driven upregulation of Ca(2+)-ATPases as a mechanism opposing the ischemic impairments in intracellular Ca(2+) regulation in hippocampal neurons. The ability of HIF-1α to modulate expression of genes coding Ca(2+)-ATPases suggests SERCA2b as a novel target for HIF-1 and may provide potential implications for HIF-1α-stabilizing strategy in activating endogenous neuroprotection.

  7. Different shades of cholesterol: Gold nanoparticles supported on MoS2 nanoribbons for enhanced colorimetric sensing of free cholesterol.

    PubMed

    Nirala, Narsingh R; Pandey, Shobhit; Bansal, Anushka; Singh, Vijay K; Mukherjee, Bratindranath; Saxena, Preeti S; Srivastava, Anchal

    2015-12-15

    In the present study, we manifest that traditionally used gold nanoparticles when supported on molybdenum disulfide nanoribbons matrix (MoS2 NRs-Au NPs) show synergistically enhanced intrinsic peroxidase like catalytic activity and can catalyze the oxidation of 3,3',5,5' tetramethyl benzidine by H2O2 to produce a highly sensitive blue shade product depending on level of free cholesterol, when tested on complex system of human serum. Further the system attests appreciable kinetics, owing to Km value as low as 0.015 mM and better loading capacity (Vmax=6.7×10(-6) M s(-1)). Additionally, the proposed system is stable for weeks with ability to perform appreciably in wide pH (3-6) and temperature range (25-60 °C). Utilizing this potential, the present work proposes a cholesterol detection color wheel which is used along with cost effective cholesterol detection strips fabricated out of proposed MoS2 NRs-Au NPs system for quick and reliable detection of free cholesterol using unaided eye.

  8. Load cell

    DOEpatents

    Spletzer, Barry L.

    2001-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs which can be combined to determine any one of the six general load components.

  9. Load cell

    DOEpatents

    Spletzer, Barry L.

    1998-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs, each directly proportional to one of the six general load components.

  10. Cholesterol Depletion from a Ceramide/Cholesterol Mixed Monolayer: A Brewster Angle Microscope Study

    NASA Astrophysics Data System (ADS)

    Mandal, Pritam; Noutsi, Pakiza; Chaieb, Sahraoui

    2016-06-01

    Cholesterol is crucial to the mechanical properties of cell membranes that are important to cells’ behavior. Its depletion from the cell membranes could be dramatic. Among cyclodextrins (CDs), methyl beta cyclodextrin (MβCD) is the most efficient to deplete cholesterol (Chol) from biomembranes. Here, we focus on the depletion of cholesterol from a C16 ceramide/cholesterol (C16-Cer/Chol) mixed monolayer using MβCD. While the removal of cholesterol by MβCD depends on the cholesterol concentration in most mixed lipid monolayers, it does not depend very much on the concentration of cholesterol in C16-Cer/Chol monolayers. The surface pressure decay during depletion were described by a stretched exponential that suggested that the cholesterol molecules are unable to diffuse laterally and behave like static traps for the MβCD molecules. Cholesterol depletion causes morphology changes of domains but these disrupted monolayers domains seem to reform even when cholesterol level was low.

  11. D38-cholesterol as a Raman active probe for imaging intracellular cholesterol storage

    PubMed Central

    Alfonso-García, Alba; Pfisterer, Simon G.; Riezman, Howard; Ikonen, Elina; Potma, Eric O.

    2015-01-01

    Abstract. We generated a highly deuterated cholesterol analog (D38-cholesterol) and demonstrated its use for selective vibrational imaging of cholesterol storage in mammalian cells. D38-cholesterol produces detectable signals in stimulated Raman scattering (SRS) imaging, is rapidly taken up by cells, and is efficiently metabolized by acyl-CoA cholesterol acyltransferase to form cholesteryl esters. Using hyperspectral SRS imaging of D38-cholesterol, we visualized cholesterol storage in lipid droplets. We found that some lipid droplets accumulated preferentially unesterified D38-cholesterol, whereas others stored D38-cholesteryl esters. In steroidogenic cells, D38-cholesteryl esters and triacylglycerols were partitioned into distinct sets of lipid droplets. Thus, hyperspectral SRS imaging of D38-cholesterol demonstrates a heterogeneous incorporation of neutral lipid species, i.e., free cholesterol, cholesteryl esters, and triacylglycerols, between individual lipid droplets in a cell. PMID:26719944

  12. The Drosophila DHR96 nuclear receptor binds cholesterol and regulates cholesterol homeostasis

    PubMed Central

    Horner, Michael A.; Pardee, Keith; Liu, Suya; King-Jones, Kirst; Lajoie, Gilles; Edwards, Aled; Krause, Henry M.; Thummel, Carl S.

    2009-01-01

    Cholesterol homeostasis is required to maintain normal cellular function and avoid the deleterious effects of hypercholesterolemia. Here we show that the Drosophila DHR96 nuclear receptor binds cholesterol and is required for the coordinate transcriptional response of genes that are regulated by cholesterol and involved in cholesterol uptake, trafficking, and storage. DHR96 mutants die when grown on low levels of cholesterol and accumulate excess cholesterol when maintained on a high-cholesterol diet. The cholesterol accumulation phenotype can be attributed to misregulation of npc1b, an ortholog of the mammalian Niemann-Pick C1-like 1 gene NPC1L1, which is essential for dietary cholesterol uptake. These studies define DHR96 as a central regulator of cholesterol homeostasis. PMID:19952106

  13. The Drosophila DHR96 nuclear receptor binds cholesterol and regulates cholesterol homeostasis.

    PubMed

    Horner, Michael A; Pardee, Keith; Liu, Suya; King-Jones, Kirst; Lajoie, Gilles; Edwards, Aled; Krause, Henry M; Thummel, Carl S

    2009-12-01

    Cholesterol homeostasis is required to maintain normal cellular function and avoid the deleterious effects of hypercholesterolemia. Here we show that the Drosophila DHR96 nuclear receptor binds cholesterol and is required for the coordinate transcriptional response of genes that are regulated by cholesterol and involved in cholesterol uptake, trafficking, and storage. DHR96 mutants die when grown on low levels of cholesterol and accumulate excess cholesterol when maintained on a high-cholesterol diet. The cholesterol accumulation phenotype can be attributed to misregulation of npc1b, an ortholog of the mammalian Niemann-Pick C1-like 1 gene NPC1L1, which is essential for dietary cholesterol uptake. These studies define DHR96 as a central regulator of cholesterol homeostasis.

  14. D38-cholesterol as a Raman active probe for imaging intracellular cholesterol storage

    NASA Astrophysics Data System (ADS)

    Alfonso-García, Alba; Pfisterer, Simon G.; Riezman, Howard; Ikonen, Elina; Potma, Eric O.

    2016-06-01

    We generated a highly deuterated cholesterol analog (D38-cholesterol) and demonstrated its use for selective vibrational imaging of cholesterol storage in mammalian cells. D38-cholesterol produces detectable signals in stimulated Raman scattering (SRS) imaging, is rapidly taken up by cells, and is efficiently metabolized by acyl-CoA cholesterol acyltransferase to form cholesteryl esters. Using hyperspectral SRS imaging of D38-cholesterol, we visualized cholesterol storage in lipid droplets. We found that some lipid droplets accumulated preferentially unesterified D38-cholesterol, whereas others stored D38-cholesteryl esters. In steroidogenic cells, D38-cholesteryl esters and triacylglycerols were partitioned into distinct sets of lipid droplets. Thus, hyperspectral SRS imaging of D38-cholesterol demonstrates a heterogeneous incorporation of neutral lipid species, i.e., free cholesterol, cholesteryl esters, and triacylglycerols, between individual lipid droplets in a cell.

  15. Dietary cholesterol and plasma lipoprotein profiles: Randomized controlled trials

    USDA-ARS?s Scientific Manuscript database

    Early work suggested that dietary cholesterol increased plasma total cholesterol concentrations in humans. Given the relationship between elevated plasma cholesterol concentrations and cardiovascular disease risk, dietary guidelines have consistently recommended limiting food sources of cholesterol....

  16. Fish protein hydrolysates affect cholesterol metabolism in rats fed non-cholesterol and high-cholesterol diets.

    PubMed

    Hosomi, Ryota; Fukunaga, Kenji; Arai, Hirofumi; Kanda, Seiji; Nishiyama, Toshimasa; Yoshida, Munehiro

    2012-03-01

    Fish consumption is well known to provide health benefits in both experimental animals and human subjects. Numerous studies have demonstrated the beneficial effects of various protein hydrolysates on lipid metabolism. In this context, this study examined the effect of fish protein hydrolysates (FPH) on cholesterol metabolism compared with the effect of casein. FPHs were prepared from Alaska pollock meat using papain as a protease. Male Wistar rats were divided into the following four dietary groups of seven rats each: either casein (20%) or FPH (10%) + casein (10%), with or without 0.5% cholesterol and 0.1% sodium cholate. Serum and liver lipid levels, fecal cholesterol and bile acid excretions, and the hepatic expression of genes encoding proteins involved in cholesterol homeostasis were examined. In rats fed the FPH diets compared with casein diets with or without cholesterol and sodium cholate, the indexes of cholesterol metabolism-namely, serum cholesterol, triglyceride, and low-density lipoprotein-cholesterol levels-were significantly lower, whereas fecal cholesterol and bile acid excretions were higher. Rats fed the FPH diets compared with casein with cholesterol exhibited a lower liver cholesterol level via an increased liver cholesterol 7α-hydroxylase (CYP7A1) expression level. This study demonstrates that the intake of FPH has hypocholesterolemic effects through the enhancement of fecal cholesterol and bile acid excretions and CYP7A1 expression levels. Therefore, fish peptides prepared by papain digestion might provide health benefits by decreasing the cholesterol content in the blood, which would contribute to the prevention of circulatory system diseases such as arteriosclerosis.

  17. Peptide mediators of cholesterol efflux

    DOEpatents

    Bielicki, John K.; Johansson, Jan

    2013-04-09

    The present invention provides a family of non-naturally occurring polypeptides having cholesterol efflux activity that parallels that of full-length apolipoproteins (e.g., Apo AI and Apo E), and having high selectivity for ABAC1 that parallels that of full-length apolipoproteins. The invention also provides compositions comprising such polypeptides, methods of identifying, screening and synthesizing such polypeptides, and methods of treating, preventing or diagnosing diseases and disorders associated with dyslipidemia, hypercholesterolemia and inflammation.

  18. Evaluating computational models of cholesterol metabolism.

    PubMed

    Paalvast, Yared; Kuivenhoven, Jan Albert; Groen, Albert K

    2015-10-01

    Regulation of cholesterol homeostasis has been studied extensively during the last decades. Many of the metabolic pathways involved have been discovered. Yet important gaps in our knowledge remain. For example, knowledge on intracellular cholesterol traffic and its relation to the regulation of cholesterol synthesis and plasma cholesterol levels is incomplete. One way of addressing the remaining questions is by making use of computational models. Here, we critically evaluate existing computational models of cholesterol metabolism making use of ordinary differential equations and addressed whether they used assumptions and make predictions in line with current knowledge on cholesterol homeostasis. Having studied the results described by the authors, we have also tested their models. This was done primarily by testing the effect of statin treatment in each model. Ten out of eleven models tested have made assumptions in line with current knowledge of cholesterol metabolism. Three out of the ten remaining models made correct predictions, i.e. predicting a decrease in plasma total and LDL cholesterol or increased uptake of LDL upon treatment upon the use of statins. In conclusion, few models on cholesterol metabolism are able to pass a functional test. Apparently most models have not undergone the critical iterative systems biology cycle of validation. We expect modeling of cholesterol metabolism to go through many more model topologies and iterative cycles and welcome the increased understanding of cholesterol metabolism these are likely to bring.

  19. Piperine prevents cholesterol gallstones formation in mice.

    PubMed

    Song, Xiu-Yun; Xu, Shuang; Hu, Jin-Feng; Tang, Jia; Chu, Shi-Feng; Liu, Hang; Han, Ning; Li, Jing-Wei; Zhang, Dong-Ming; Li, Yue-Ting; Chen, Nai-Hong

    2015-03-15

    Biliary cholesterol may contribute to the formation of cholesterol gallstones, and regulation of these levels could be a useful therapeutic strategy for gallstones disease. Piperine (PA) is a potential cholesterol lowering agent. In this study, we assessed the effect and mechanism of PA in preventing cholesterol gallstones formation induced by feeding lithogenic diet containing high cholesterol levels to mice. C57BL/6 inbred mice were fed lithogenic or chow diets for 10 weeks, with or without PA (15, 30 and 60 mg/kg) or ursodeoxycholic acid (UDCA, 60 mg/kg) administration. Cholesterol, phospholipids and crystals in bile, the lipid in serum, pathological changes and proteins expression in liver were analyzed. The results showed that PA could decrease the cholesterol potency and crystals in bile, reduce total cholesterol (TC), triglycerides (TG) and increase high-density lipoprotein/low-density lipoprotein (HDL/LDL) levels in serum. Furthermore, PA treatment reduced liver lipid peroxidation and protected hepatobiliary cells from liver injury by decreasing malondialdehyde (MDA) and increasing superoxide dismutase (SOD). In addition, PA inhibited the expression of ATP-binding cassette transporters G5/8 (ABCG5/8) and liver X receptor (LXR) in liver, and reduced cholesterol transport from the hepatocytes to the gallbladder. It may be the mechanism of PA in preventing cholesterol gallstones formation. PA as a potential drug for prevention cholesterol gallstones merits further investigation.

  20. Cholesterol metabolism and homeostasis in the brain.

    PubMed

    Zhang, Juan; Liu, Qiang

    2015-04-01

    Cholesterol is an essential component for neuronal physiology not only during development stage but also in the adult life. Cholesterol metabolism in brain is independent from that in peripheral tissues due to blood-brain barrier. The content of cholesterol in brain must be accurately maintained in order to keep brain function well. Defects in brain cholesterol metabolism has been shown to be implicated in neurodegenerative diseases, such as Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), and some cognitive deficits typical of the old age. The brain contains large amount of cholesterol, but the cholesterol metabolism and its complex homeostasis regulation are currently poorly understood. This review will seek to integrate current knowledge about the brain cholesterol metabolism with molecular mechanisms.

  1. Regulation of biliary cholesterol secretion in the rat. Role of hepatic cholesterol esterification.

    PubMed Central

    Nervi, F; Bronfman, M; Allalón, W; Depiereux, E; Del Pozo, R

    1984-01-01

    Although the significance of the enterohepatic circulation of bile salts in the solubilization and biliary excretion of cholesterol is well established, little is known about the intrahepatic determinants of biliary cholesterol output. Studies were undertaken to elucidate some of these determinants in the rat. Feeding 1% diosgenin for 1 wk increased biliary cholesterol output and saturation by 400%. Bile flow, biliary bile salt, phospholipid and protein outputs remained in the normal range. When ethynyl estradiol (EE) was injected into these animals, biliary cholesterol output decreased to almost normal levels under circumstances of minor changes in the rates of biliary bile salt and phospholipid outputs. Similarly, when chylomicron cholesterol was intravenously injected into diosgenin-fed animals, biliary cholesterol output significantly decreased as a function of the dose of chylomicron cholesterol administered. Relative rates of hepatic cholesterol synthesis and esterification were measured in isolated hepatocytes. Although hepatic cholesterogenesis increased 300% in diosgenin-fed animals, the contribution of newly synthesized cholesterol to total biliary cholesterol output was only 19 +/- 9%, compared with 12 +/- 6% in control and 15 +/- 5% in diosgenin-fed and EE-injected rats. The rate of oleate incorporation into hepatocytic cholesterol esters was 30% inhibited in diosgenin-fed rats. When EE was injected into these animals, the rate of cholesterol esterification increased to almost 300%. To investigate further the interrelationship between hepatic cholesterol esterification and biliary cholesterol output, we studied 21 diosgenin-fed rats. Six of them received in addition EE and 10 received chylomicron cholesterol. The relationships between biliary cholesterol output as a function of both microsomal acyl-CoA:cholesterol acyltransferase (ACAT) activity and hepatic cholesterol ester concentration were significantly correlated in a reciprocal manner. From these

  2. Newly developed apolipoprotein A-I mimetic peptide promotes macrophage reverse cholesterol transport in vivo.

    PubMed

    Shimizu, Tomohiko; Tanigawa, Hiroyuki; Miura, Shin-ichiro; Kuwano, Takashi; Takata, Kohei; Suematsu, Yasunori; Imaizumi, Satoshi; Yahiro, Eiji; Zhang, Bo; Uehara, Yoshinari; Saku, Keijiro

    2015-08-01

    We elucidated the effect of newly developed Fukuoka Apolipoprotein A-I Mimetic Peptide (FAMP) on in vivo macrophage reverse cholesterol transport (RCT) and the underlying mechanisms. Cholesteryl ester transfer protein transgenic mice were divided into FAMP, and placebo control groups, and injected with FAMP or phosphate buffer saline intraperitoneally for 5 days. The FAMP group showed a significant decrease in plasma high-density lipoprotein cholesterol (HDL-C), and plasma from the FAMP group had an increased ability to promote ATP-binding cassette transporter A1 (ABCA1)-mediated cholesterol efflux from bone marrow macrophages ex vivo. Furthermore, mice were injected intraperitoneally with (3)H-cholesterol-labeled and cholesterol-loaded macrophages and monitored for the appearance of (3)H-tracer. The amount of (3)H-tracer excreted into feces over 48h in the FAMP group was significantly higher than that in the control group. (3)H-cholesterol ester (CE)-HDL was injected intravenously and (3)H-cholesterol in blood was counted. In the FAMP group, plasma (3)H-CE-HDL decreased rapidly, and treatment with FAMP markedly increased the fractional catabolic rate. The administration of FAMP promoted ABCA1-dependent efflux ex vivo, HDL turnover in vivo, and macrophage RCT in vivo despite reduced plasma HDL-C levels. FAMP might have atheroprotective potential. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. Matrix metalloproteinase 8 degrades apolipoprotein A-I and reduces its cholesterol efflux capacity.

    PubMed

    Salminen, Aino; Åström, Pirjo; Metso, Jari; Soliymani, Rabah; Salo, Tuula; Jauhiainen, Matti; Pussinen, Pirkko J; Sorsa, Timo

    2015-04-01

    Various cell types in atherosclerotic lesions express matrix metalloproteinase (MMP)-8. We investigated whether MMP-8 affects the structure and antiatherogenic function of apolipoprotein (apo) A-I, the main protein component of HDL particles. Furthermore, we studied serum lipid profiles and cholesterol efflux capacity in MMP-8-deficient mouse model. Incubation of apoA-I (28 kDa) with activated MMP-8 yielded 22 kDa and 25 kDa apoA-I fragments. Mass spectrometric analyses revealed that apoA-I was cleaved at its carboxyl-terminal part. Treatment of apoA-I and HDL with MMP-8 resulted in significant reduction (up to 84%, P < 0.001) in their ability to facilitate cholesterol efflux from cholesterol-loaded THP-1 macrophages. The cleavage of apoA-I by MMP-8 and the reduction in its cholesterol efflux capacity was inhibited by doxycycline. MMP-8-deficient mice had significantly lower serum triglyceride (TG) levels (P = 0.003) and larger HDL particles compared with wild-type (WT) mice. However, no differences were observed in the apoA-I levels or serum cholesterol efflux capacities between the mouse groups. Proteolytic modification of apoA-I by MMP-8 may impair the first steps of reverse cholesterol transport, leading to increased accumulation of cholesterol in the vessel walls. Eventually, inhibition of MMPs by doxycycline may reduce the risk for atherosclerotic vascular diseases.

  4. The macrophage and its related cholesterol efflux as a HDL function index in atherosclerosis.

    PubMed

    Yamamoto, Suguru; Narita, Ichiei; Kotani, Kazuhiko

    2016-06-01

    The macrophage and its related cholesterol efflux are considered to be a key player in atherosclerotic formation in relation to the function of high-density lipoprotein (HDL). The HDL function can be evaluated by the reaction between lipid-loaded macrophages and lipid-acceptors in the HDL fraction from the plasma, apolipoprotein B-depleted serum, and/or whole serum/plasma. Recent studies have reported that an impaired cholesterol efflux of HDL is observed in patients with cardiometabolic diseases, such as dyslipidemia, diabetes mellitus, and chronic kidney disease. A population-based cohort study has reported an inverse association between the cholesterol efflux capacity of HDL and the incidence of atherosclerotic disease, regardless of the serum HDL-cholesterol level. Moreover, in this paper, when we summarized several clinical interventional studies of statin treatment that examined cholesterol efflux, a potential increase in the efflux in patients treated with statins was implied. However, the effect was not fully defined in the current situation because of the small sample sizes, lack of a unified protocol for measuring the efflux, and short-term intervention periods without cardiovascular outcomes in available studies. Further investigation is necessary to determine the effect of drugs on cholesterol efflux. With additional advanced studies, cholesterol efflux is a promising laboratory index to understand the HDL function. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Novel technique for generating macrophage foam cells for in vitro reverse cholesterol transport studies[S

    PubMed Central

    Sengupta, Bhaswati; Narasimhulu, Chandrakala Aluganti; Parthasarathy, Sampath

    2013-01-01

    Generation of foam cells, an essential step for reverse cholesterol transport studies, uses the technique of receptor-dependent macrophage loading with radiolabeled acetylated LDL. In this study, we used the ability of a biologically relevant detergent molecule, lysophosphatidylcholine (lyso-PtdCho), to form mixed micelles with cholesterol or cholesteryl ester (CE) to generate macrophage foam cells. Fluorescent or radiolabeled cholesterol/lyso-PtdCho mixed micelles were prepared and incubated with RAW 264.7 or mouse peritoneal macrophages. Results showed that such micelles were quite stable at 4°C and retained the solubilized cholesterol during one month of storage. Macrophages incubated with cholesterol or CE (unlabeled, fluorescently labeled, or radiolabeled)/lyso-PtdCho mixed micelles accumulated CE as documented by microscopy, lipid staining, labeled oleate incorporation, and by TLC. Such foam cells unloaded cholesterol when incubated with HDL but not with oxidized HDL. We propose that stable cholesterol or CE/lyso-PtdCho micelles would offer advantages over existing methods. PMID:24115226

  6. Cholesterol can modulate mitochondrial aquaporin-8 expression in human hepatic cells.

    PubMed

    Danielli, Mauro; Capiglioni, Alejo M; Marrone, Julieta; Calamita, Giuseppe; Marinelli, Raúl A

    2017-05-01

    Hepatocyte mitochondrial aquaporin-8 (mtAQP8) works as a multifunctional membrane channel protein that facilitates the uptake of ammonia for its detoxification to urea as well as the mitochondrial release of hydrogen peroxide. Since early oligonucleotide microarray studies in liver of cholesterol-fed mice showed an AQP8 downregulation, we tested whether alterations of cholesterol content per se modulate mtAQP8 expression in human hepatocyte-derived Huh-7 cells. Cholesterol loading with methyl-β-cyclodextrin (mβCD):cholesterol complexes downregulated the proteolytic activation of cholesterol-responsive sterol regulatory element-binding protein (SREBP) transcriptions factors 1 and 2, and the expression of the target gene 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR). Under such conditions, mtAQP8 mRNA and protein expressions were significantly reduced. In contrast, cholesterol depletion using mβCD alone increased SREBP-1 and 2 activation and upregulated HMGCR and mtAQP8 mRNA and protein expressions. The results suggest that cholesterol can regulate transcriptionally human hepatocyte mtAQP8 expression likely via SREBPs. The functional implications of our findings are discussed. © 2017 IUBMB Life, 69(5):341-346, 2017. © 2017 International Union of Biochemistry and Molecular Biology.

  7. igr Genes and Mycobacterium tuberculosis cholesterol metabolism.

    PubMed

    Chang, Jennifer C; Miner, Maurine D; Pandey, Amit K; Gill, Wendy P; Harik, Nada S; Sassetti, Christopher M; Sherman, David R

    2009-08-01

    Recently, cholesterol was identified as a physiologically important nutrient for Mycobacterium tuberculosis survival in chronically infected mice. However, it remained unclear precisely when cholesterol is available to the bacterium and what additional bacterial functions are required for its metabolism. Here, we show that the igr locus, which we previously found to be essential for intracellular growth and virulence of M. tuberculosis, is required for cholesterol metabolism. While igr-deficient strains grow identically to the wild type in the presence of short- and long-chain fatty acids, the growth of these bacteria is completely inhibited in the presence of cholesterol. Interestingly, this mutant is still able to respire under cholesterol-dependent growth inhibition, suggesting that the bacteria can metabolize other carbon sources during cholesterol toxicity. Consistent with this hypothesis, we found that the growth-inhibitory effect of cholesterol in vitro depends on cholesterol import, as mutation of the mce4 sterol uptake system partially suppresses this effect. In addition, the Delta igr mutant growth defect during the early phase of disease is completely suppressed by mutating mce4, implicating cholesterol intoxication as the primary mechanism of attenuation. We conclude that M. tuberculosis metabolizes cholesterol throughout infection.

  8. Cholesterol, the central lipid of mammalian cells

    PubMed Central

    Maxfield, Frederick R.; van Meer, Gerrit

    2010-01-01

    Summary of recent advances Despite its importance for mammalian cell biology and human health, there are many basic aspects of cholesterol homeostasis that are not well understood. Even for the well-characterized delivery of cholesterol to cells via lipoproteins, a novel regulatory mechanism has been discovered recently, involving a serum protein called PCSK9, which profoundly affects lipoproteins and their receptors. Cells can export cholesterol by processes that require the activity of ABC transporters, but the molecular mechanisms for cholesterol transport remain unclear. Cholesterol levels in different organelles vary by 5–10 fold, and the mechanisms for maintaining these differences are now partially understood. Several proteins have been proposed to play a role in the inter-organelle movement of cholesterol, but many aspects of the mechanisms for regulating intracellular transport and distribution of cholesterol remain to be worked out. The endoplasmic reticulum is the main organelle responsible for regulation of cholesterol synthesis, and careful measurements have shown that the proteins responsible for sterol sensing respond over a very narrow range of cholesterol concentrations to provide very precise, switch-like control over cholesterol synthesis. PMID:20627678

  9. Liver X receptors regulate adrenal cholesterol balance

    PubMed Central

    Cummins, Carolyn L.; Volle, David H.; Zhang, Yuan; McDonald, Jeffrey G.; Sion, Benoît; Lefrançois-Martinez, Anne-Marie; Caira, Françoise; Veyssière, Georges; Mangelsdorf, David J.; Lobaccaro, Jean-Marc A.

    2006-01-01

    Cholesterol is the obligate precursor to adrenal steroids but is cytotoxic at high concentrations. Here, we show the role of the liver X receptors (LXRα and LXRβ) in preventing accumulation of free cholesterol in mouse adrenal glands by controlling expression of genes involved in all aspects of cholesterol utilization, including the steroidogenic acute regulatory protein, StAR, a novel LXR target. Under chronic dietary stress, adrenal glands from Lxrαβ–/– mice accumulated free cholesterol. In contrast, wild-type animals maintained cholesterol homeostasis through basal expression of genes involved in cholesterol efflux and storage (ABC transporter A1 [ABCA1], apoE, SREBP-1c) while preventing steroidogenic gene (StAR) expression. Upon treatment with an LXR agonist that mimics activation by oxysterols, expression of these target genes was increased. Basally, Lxrαβ–/– mice exhibited a marked decrease in ABCA1 and a derepression of StAR expression, causing a net decrease in cholesterol efflux and an increase in steroidogenesis. These changes occurred under conditions that prevented the acute stress response and resulted in a phenotype more specific to the loss of LXRα, including hypercorticosteronemia, cholesterol ester accumulation, and adrenomegaly. These results imply LXRα provides a safety valve to limit free cholesterol levels as a basal protective mechanism in the adrenal gland, where cholesterol is under constant flux. PMID:16823488

  10. Regulation of Cholesterol Metabolism in the Dog

    PubMed Central

    Pertsemlidis, Demetrius; Kirchman, Ernest H.; Ahrens, E. H.

    1973-01-01

    In six adult pedigreed dogs the effects of high-cholesterol diets or bile diversion on the sizes of body cholesterol pools were studied at autopsy. Total body cholesterol was determined by measuring the cholesterol content of discrete organs and of the eviscerated carcass: neither cholesterol feeding nor bile diversion had altered total body cholesterol or the cholesterol content of individual organs and tissues. These results validated the conclusion based on sterol balance data obtained during life, that high-cholesterol feeding did not lead to substantial expansion of tissue cholesterol pools. The total amount of exchangeable cholesterol in the animals with an intact enterohepatic circulation, when estimated from isotopic data, was essentially the same as that measured chemically: this indicated that there was little or no nonexchangeable cholesterol in these dogs, except in skin and nervous tissue, regardless of the cholesterol content of the diet. This correspondence of estimates was not obtained in the bile-diverted dogs: we propose that the defect in the isotopic estimates was due to the accelerated rate of cholesterol synthesis in these animals. Gross and microscopic morphology of all organs and tissues was examined. Abnormal findings were limited to the biliary tract and the urinary collecting system of the two bile-diverted dogs: multiple bilirubinate gallstones were found, and mild pyelitis and ureteritis were present on the side of the bilio-renal shunt, but the urinary bladder was normal. Histologic evidence of moderate degree of cholangitis was found in one of the two bile-shunted dogs, but in neither dog was there evidence of impedance of bile flow. PMID:4727465

  11. Reduction of blood serum cholesterol

    NASA Technical Reports Server (NTRS)

    Winitz, M. (Inventor)

    1974-01-01

    By feeding a human subject as the sole source of sustenance a defined diet wherein the carbohydrate consists substantially entirely of glucose, maltose or a polysaccharide of glucose, the blood serum cholesterol level of the human subject is substantially reduced. If 25 percent of the carbohydrate is subsequently supplied in the form of sucrose, an immediate increase from the reduced level is observed. The remainder of the defined diet normally includes a source of amino acids, such as protein or a protein hydrolysate, vitamins, minerals and a source of essential fatty acid.

  12. Arctigenin promotes cholesterol efflux from THP-1 macrophages through PPAR-γ/LXR-α signaling pathway

    SciTech Connect

    Xu, Xiaolin; Li, Qian; Pang, Liewen; Huang, Guoqian; Huang, Jiechun; Shi, Meng; Sun, Xiaotian; Wang, Yiqing

    2013-11-15

    Highlights: •Arctigenin enhanced cholesterol efflux in oxLDL-loaded THP-1 macrophages. •The expression of ABCA1, ABCG1 and apoE was upregulated in arctigenin-treated cells. •Arctigenin promoted the expression of PPAR-γ and LXR-α. •Inhibition of PPAR-γ or LXR-α reversed arctigenin-mediated biological effects. •Arctigenin promotes cholesterol efflux via activation of PPAR-γ/LXR-α/ABCA1 pathway. -- Abstract: Cholesterol efflux from macrophages is a critical mechanism to prevent the development of atherosclerosis. Here, we sought to investigate the effects of arctigenin, a bioactive component of Arctium lappa, on the cholesterol efflux in oxidized low-density lipoprotein (oxLDL)-loaded THP-1 macrophages. Our data showed that arctigenin significantly accelerated apolipoprotein A-I- and high-density lipoprotein-induced cholesterol efflux in both dose- and time-dependent manners. Moreover, arctigenin treatment enhanced the expression of ATP binding cassette transporter A1 (ABCA1), ABCG1, and apoE, all of which are key molecules in the initial step of cholesterol efflux, at both mRNA and protein levels. Arctigenin also caused a concentration-dependent elevation in the expression of peroxisome proliferator-activated receptor-gamma (PPAR-γ) and liver X receptor-alpha (LXR-α). The arctigenin-mediated induction of ABCA1, ABCG1, and apoE was abolished by specific inhibition of PPAR-γ or LXR-α using small interfering RNA technology. Our results collectively indicate that arctigenin promotes cholesterol efflux in oxLDL-loaded THP-1 macrophages through upregulation of ABCA1, ABCG1 and apoE, which is dependent on the enhanced expression of PPAR-γ and LXR-α.

  13. [Diagnostic importance of HDL cholesterol determination].

    PubMed

    Reissner, J; Herrmann, W

    1990-01-01

    The present paper describes the sensitivity to quantification of changes of HDL-cholesterol in serum by two different precipitation and analytical techniques during the treatment of patients. After the precipitation of VLDL and LDL by phosphotungstic acid/magnesium chloride the chemical determination of HDL-cholesterol in serum with the Liebermann-Burchard reaction yields different results in comparison to enzymatic HDL-cholesterol determined in serum supernatant after the precipitation by polyethylene glycol 20.000. Correlation analyses of apolipoprotein A-I with enzymatic HDL-, HDL2-, HDL3-cholesterol or electrophoretic alpha-cholesterol demonstrate that the therapeutically induced changes (by training and diet) of lipid composition are more correctly reflected by the enzymatic determination of HDL-cholesterol after serum precipitation by polyethylene glycol.

  14. microRNAs and cholesterol metabolism

    PubMed Central

    Moore, Kathryn J.; Rayner, Katey J.; Suárez, Yajaira; Fernández-Hernando, Carlos

    2010-01-01

    Cholesterol metabolism is tightly regulated at the cellular level. In addition to classic transcriptional regulation of cholesterol metabolism (e.g., by SREBP and LXR), members of a class of non-coding RNAs termed microRNAs (miRNAs) have recently been identified to be potent post-transcriptional regulators of lipid metabolism genes, including cholesterol homeostasis. We and others have recently shown that miR-33 regulates cholesterol efflux and HDL biogenesis by downregulating the expression of the ABC transporters, ABCA1 and ABCG1. In addition to miR-33, miR-122 and miR-370 have been shown to play important roles in regulating cholesterol and fatty acid metabolism. These new data suggest important roles of microRNAs in the epigenetic regulation of cholesterol metabolism and have opened new avenues for the treatment of dyslipidemias. PMID:20880716

  15. Molecular Mechanism of Cyclodextrin Mediated Cholesterol Extraction

    PubMed Central

    López, Cesar A.; de Vries, Alex H.; Marrink, Siewert J.

    2011-01-01

    The depletion of cholesterol from membranes, mediated by β-cyclodextrin (β-CD) is well known and documented, but the molecular details of this process are largely unknown. Using molecular dynamics simulations, we have been able to study the CD mediated extraction of cholesterol from model membranes, in particular from a pure cholesterol monolayer, at atomic resolution. Our results show that efficient cholesterol extraction depends on the structural distribution of the CDs on the surface of the monolayer. With a suitably oriented dimer, cholesterol is extracted spontaneously on a nanosecond time scale. Additional free energy calculations reveal that the CDs have a strong affinity to bind to the membrane surface, and, by doing so, destabilize the local packing of cholesterol molecules making their extraction favorable. Our results have implications for the interpretation of experimental measurements, and may help in the rational design of efficient CD based nano-carriers. PMID:21455285

  16. Cholesterol Oxidation in Fish and Fish Products.

    PubMed

    Dantas, Natalie Marinho; Sampaio, Geni Rodrigues; Ferreira, Fernanda Silva; Labre, Tatiana da Silva; Torres, Elizabeth Aparecida Ferraz da Silva; Saldanha, Tatiana

    2015-12-01

    Fish and fish products are important from a nutritional point of view due to the presence of high biological value proteins and the high content of polyunsaturated fatty acids, especially those of the n-3 series, and above all eicosapentaenoic acid and docosahexaenoic acid. However, these important food products also contain significant amounts of cholesterol. Although cholesterol participates in essential functions in the human body, it is unstable, especially in the presence of light, oxygen, radiation, and high temperatures that can cause the formation of cholesterol oxidation products or cholesterol oxides, which are prejudicial to human health. Fish processing involves high and low temperatures, as well as other methods for microbiological control, which increases shelf life and consequently added value; however, such processes favor the formation of cholesterol oxidation products. This review brings together data on the formation of cholesterol oxides during the preparation and processing of fish into food products which are recognized and recommended for their nutritional properties.

  17. Imbalanced cholesterol metabolism in Alzheimer's disease.

    PubMed

    Xue-shan, Zhao; Juan, Peng; Qi, Wu; Zhong, Ren; Li-hong, Pan; Zhi-han, Tang; Zhi-sheng, Jiang; Gui-xue, Wang; Lu-shan, Liu

    2016-05-01

    Alzheimer's disease (AD) is a complex and multifactorial neurodegenerative disease that is mainly caused by β-amyloid accumulation. A large number of studies have shown that elevated cholesterol levels may perform a function in AD pathology, and several cholesterol-related gene polymorphisms are associated with this disease. Although numerous studies have shown the important function of cholesterol in AD pathogenesis and development, the underlying mechanism remains unclear. To further elucidate cholesterol metabolism disorder and AD, we first, review metabolism and regulation of the cholesterol in the brain. Second, we summarize the literature stating that hypercholesterolemia is one of the risk factors of AD. Third, we discuss the main mechanisms of abnormal cholesterol metabolism that increase the risk of AD. Finally, the relationships between AD and apolipoprotein E, PCSK9, and LRP1 are discussed in this article.

  18. Effects of dietary cholesterol and simvastatin on cholesterol synthesis in Smith-Lemli-Opitz syndrome (SLOS)

    PubMed Central

    Chan, Yen-Ming; Merkens, Louise S.; Connor, William E.; Roullet, Jean-Baptiste; Penfield, Jennifer A.; Jordan, Julia M.; Steiner, Robert D.; Jones, Peter J.H.

    2009-01-01

    Deficient cholesterol and/or excessive 7-dehydrocholesterol (7-DHC) may be responsible for the pathology of Smith-Lemli-Opitz syndrome (SLOS). Both high cholesterol diets given to ameliorate cholesterol deficiency while decreasing 7-DHC, and cholesterol-enriched diets plus simvastatin to further decrease sterol synthesis, have been used as potential therapies. However, the effect of dietary cholesterol and simvastatin on cholesterol synthesis in SLOS has not been reported. Twelve SLOS subjects enrolled in the study: Nine had received a high cholesterol diet (HI) for 3 years, and three were studied after 4 weeks on a low cholesterol diet (LO). Cholesterol fractional synthesis rate (FSR) was measured after oral administration of deuterium oxide, using gas-chromatography-isotope ratio mass spectrometry. FSR was lower in HI compared with LO (HI: 1.46±0.62%/d; LO: 4.77±0.95%/d; P<0.001). Three HI subjects were re-tested after 0.8 years taking simvastatin (HI+ST). Simvastatin tended to reduce FSR and significantly decreased (P<0.01) plasma 7-DHC compared to cholesterol supplementation alone. The study demonstrates the utility of the deuterium incorporation method to understand the effect of therapeutic interventions in SLOS. The data suggest that dietary cholesterol supplementation reduces cholesterol synthesis in SLOS and further support the rationale for the combined treatment of SLOS with a cholesterol-enriched diet and simvastatin. PMID:19430384

  19. Cholesterol metabolism and serum non-cholesterol sterols: summary of 13 plant stanol ester interventions.

    PubMed

    Hallikainen, Maarit; Simonen, Piia; Gylling, Helena

    2014-04-27

    The efficacy and safety of plant stanols added to food products as serum cholesterol lowering agents have been demonstrated convincingly, but their effects on cholesterol metabolism and on serum non-cholesterol sterols is less evaluated. The aim of this study was to assess the validity of serum non-cholesterol sterols and squalene as bioindices of cholesterol synthesis and absorption, and to examine how the individual serum non-cholesterol sterols respond to consumption of plant stanols. We collected all randomized, controlled plant stanol ester (STAEST) interventions in which serum cholestanol, plant sterols campesterol and sitosterol, and at least two serum cholesterol precursors had been analysed. According to these criteria, there was a total of 13 studies (total 868 subjects without lipid-lowering medication; plant stanol doses varied from 0.8 to 8.8 g/d added in esterified form; the duration of the studies varied from 4 to 52 weeks). Serum non-cholesterol sterols were assayed with gas-liquid chromatography, cholesterol synthesis with the sterol balance technique, and fractional cholesterol absorption with the dual continuous isotope feeding method. The results demonstrated that during the control and the STAEST periods, the serum plant sterol/cholesterol- and the cholestanol/cholesterol-ratios reflected fractional cholesterol absorption, and the precursor sterol/cholesterol-ratios reflected cholesterol synthesis. Plant sterol levels were dose-dependently reduced by STAEST so that 2 g of plant stanols reduced serum campesterol/cholesterol-ratio on average by 32%. Serum cholestanol/cholesterol-ratio was reduced less frequently than those of the plant sterols by STAEST, and the cholesterol precursor sterol ratios did not change consistently in the individual studies emphasizing the importance of monitoring more than one surrogate serum marker. Serum non-cholesterol sterols are valid markers of cholesterol absorption and synthesis even during cholesterol

  20. Cholesterol metabolism and serum non-cholesterol sterols: summary of 13 plant stanol ester interventions

    PubMed Central

    2014-01-01

    Background The efficacy and safety of plant stanols added to food products as serum cholesterol lowering agents have been demonstrated convincingly, but their effects on cholesterol metabolism and on serum non-cholesterol sterols is less evaluated. The aim of this study was to assess the validity of serum non-cholesterol sterols and squalene as bioindices of cholesterol synthesis and absorption, and to examine how the individual serum non-cholesterol sterols respond to consumption of plant stanols. Methods We collected all randomized, controlled plant stanol ester (STAEST) interventions in which serum cholestanol, plant sterols campesterol and sitosterol, and at least two serum cholesterol precursors had been analysed. According to these criteria, there was a total of 13 studies (total 868 subjects without lipid-lowering medication; plant stanol doses varied from 0.8 to 8.8 g/d added in esterified form; the duration of the studies varied from 4 to 52 weeks). Serum non-cholesterol sterols were assayed with gas–liquid chromatography, cholesterol synthesis with the sterol balance technique, and fractional cholesterol absorption with the dual continuous isotope feeding method. Results The results demonstrated that during the control and the STAEST periods, the serum plant sterol/cholesterol- and the cholestanol/cholesterol-ratios reflected fractional cholesterol absorption, and the precursor sterol/cholesterol-ratios reflected cholesterol synthesis. Plant sterol levels were dose-dependently reduced by STAEST so that 2 g of plant stanols reduced serum campesterol/cholesterol-ratio on average by 32%. Serum cholestanol/cholesterol-ratio was reduced less frequently than those of the plant sterols by STAEST, and the cholesterol precursor sterol ratios did not change consistently in the individual studies emphasizing the importance of monitoring more than one surrogate serum marker. Conclusions Serum non-cholesterol sterols are valid markers of cholesterol absorption

  1. Metabolism of adrenal cholesterol in man

    PubMed Central

    Borkowski, Abraham; Delcroix, Claude; Levin, Sam

    1972-01-01

    The kinetics of plasma and adrenal cholesteral equilibration were analyzed in patients undergoing bilateral adrenalectomy for generalized mammary carcinoma. A biological model is proposed to help in the understanding of adrenal cholesterol physiology. It comprises two intracellular compartments: (1) A compartment of free adrenal cholesterol which is small (of the order of 17 mg) but turns over very fast; it is renewed approximately 8 times per day: 3 times by the inflow of free plasma cholesterol, and 5 times by the hydrolysis of esterified adrenal cholesterol, the contribution of adrenal cholesterol synthesis appearing to be relatively small. (2) A compartment of esterified adrenal cholesterol which is 20 times larger; it is constantly renewed by in situ esterification and hydrolysis with a daily fractional turnover rate of the order of 0.25. The direct and selective accumulation of plasma cholesteryl esters is practically absent. Only free adrenal cholesterol returns to plasma, mostly after conversion into steroid “hormones.” However small the synthesis of adrenal cholesterol may be, it seems more important in the zona “reticularis.” On the other hand, the inflow of plasma cholesterol and the turnover of the free adrenal compartment tend to be faster in the zona “fasciculata.” The equilibration of plasma and adrenal cholesterol can proceed unmodified under conditions of ACTH suppression. In one patient with Cushing's disease the size of the two adrenal compartments was clearly increased but their equilibration with plasma cholesterol proceeded normally. In another patient the kinetics of hydrocortisone corresponded to those of free adrenal cholesterol in the control studies. PMID:4338119

  2. Macrophage-mediated cholesterol handling in atherosclerosis.

    PubMed

    Chistiakov, Dimitry A; Bobryshev, Yuri V; Orekhov, Alexander N

    2016-01-01

    Formation of foam cells is a hallmark at the initial stages of atherosclerosis. Monocytes attracted by pro-inflammatory stimuli attach to the inflamed vascular endothelium and penetrate to the arterial intima where they differentiate to macrophages. Intimal macrophages phagocytize oxidized low-density lipoproteins (oxLDL). Several scavenger receptors (SR), including CD36, SR-A1 and lectin-like oxLDL receptor-1 (LOX-1), mediate oxLDL uptake. In late endosomes/lysosomes of macrophages, oxLDL are catabolysed. Lysosomal acid lipase (LAL) hydrolyses cholesterol esters that are enriched in LDL to free cholesterol and free fatty acids. In the endoplasmic reticulum (ER), acyl coenzyme A: cholesterol acyltransferase-1 (ACAT1) in turn catalyses esterification of cholesterol to store cholesterol esters as lipid droplets in the ER of macrophages. Neutral cholesteryl ester hydrolases nCEH and NCEH1 are involved in a secondary hydrolysis of cholesterol esters to liberate free cholesterol that could be then out-flowed from macrophages by cholesterol ATP-binding cassette (ABC) transporters ABCA1 and ABCG1 and SR-BI. In atherosclerosis, disruption of lipid homoeostasis in macrophages leads to cholesterol accumulation and formation of foam cells.

  3. Structure of Cholesterol in Lipid Rafts

    NASA Astrophysics Data System (ADS)

    Toppozini, Laura; Meinhardt, Sebastian; Armstrong, Clare L.; Yamani, Zahra; Kučerka, Norbert; Schmid, Friederike; Rheinstädter, Maikel C.

    2014-11-01

    Rafts, or functional domains, are transient nano-or mesoscopic structures in the plasma membrane and are thought to be essential for many cellular processes such as signal transduction, adhesion, trafficking, and lipid or protein sorting. Observations of these membrane heterogeneities have proven challenging, as they are thought to be both small and short lived. With a combination of coarse-grained molecular dynamics simulations and neutron diffraction using deuterium labeled cholesterol molecules, we observe raftlike structures and determine the ordering of the cholesterol molecules in binary cholesterol-containing lipid membranes. From coarse-grained computer simulations, heterogenous membranes structures were observed and characterized as small, ordered domains. Neutron diffraction was used to study the lateral structure of the cholesterol molecules. We find pairs of strongly bound cholesterol molecules in the liquid-disordered phase, in accordance with the umbrella model. Bragg peaks corresponding to ordering of the cholesterol molecules in the raftlike structures were observed and indexed by two different structures: a monoclinic structure of ordered cholesterol pairs of alternating direction in equilibrium with cholesterol plaques, i.e., triclinic cholesterol bilayers.

  4. Regulation of Plasma Cholesterol by Lipoprotein Receptors

    NASA Astrophysics Data System (ADS)

    Brown, Michael S.; Kovanen, Petri T.; Goldstein, Joseph L.

    1981-05-01

    The lipoprotein transport system holds the key to understanding the mechanisms by which genes, diet, and hormones interact to regulate the plasma cholesterol level in man. Crucial components of this system are lipoprotein receptors in the liver and extrahepatic tissues that mediate the uptake and degradation of cholesterol-carrying lipoproteins. The number of lipoprotein receptors, and hence the efficiency of disposal of plasma cholesterol, can be increased by cholesterol-lowering drugs. Regulation of lipoprotein receptors can be exploited pharmacologically in the therapy of hypercholesterolemia and atherosclerosis in man.

  5. Cholesterol modulates Orai1 channel function

    PubMed Central

    Derler, Isabella; Jardin, Isaac; Stathopulos, Peter B.; Muik, Martin; Fahrner, Marc; Zayats, Vasilina; Pandey, Saurabh K.; Poteser, Michael; Lackner, Barbara; Absolonova, Marketa; Schindl, Rainer; Groschner, Klaus; Ettrich, Rüdiger; Ikura, Mitsu; Romanin, Christoph

    2017-01-01

    STIM1 (stromal interaction molecule 1) and Orai proteins are the essential components of Ca2+ release–activated Ca2+ (CRAC) channels. We focused on the role of cholesterol in the regulation of STIM1-mediated Orai1 currents. Chemically induced cholesterol depletion enhanced store-operated Ca2+ entry (SOCE) and Orai1 currents. Furthermore, cholesterol depletion in mucosal-type mast cells augmented endogenous CRAC currents, which were associated with increased degranulation, a process that requires calcium influx. Single point mutations in the Orai1 amino terminus that would be expected to abolish cholesterol binding enhanced SOCE to a similar extent as did cholesterol depletion. The increase in Orai1 activity in cell expressing these cholesterol-binding–deficient mutants occurred without affecting the amount in the plasma membrane or the coupling of STIM1 to Orai1. We detected cholesterol binding to an Orai1 amino-terminal fragment in vitro and to full-length Orai1 in cells. Thus, our data showed that Orai1 senses the amount of cholesterol in the plasma membrane and that the interaction of Orai1 with cholesterol inhibits its activity, thereby limiting SOCE. PMID:26814231

  6. Cholesterol and late-life cognitive decline.

    PubMed

    van Vliet, Peter

    2012-01-01

    High cholesterol levels are a major risk factor for cardiovascular disease, but their role in dementia and cognitive decline is less clear. This review highlights current knowledge on the role of cholesterol in late-life cognitive function, cognitive decline, and dementia. When measured in midlife, high cholesterol levels associate with an increased risk of late-life dementia and cognitive decline. However, when measured in late-life, high cholesterol levels show no association with cognitive function, or even show an inverse relation. Although statin treatment has been shown to associate with a lower risk of dementia and cognitive decline in observational studies, randomized controlled trials show no beneficial effect of statin treatment on late-life cognitive function. Lowering cholesterol levels may impair brain function, since cholesterol is essential for synapse formation and maturation and plays an important role in the regulation of signal transduction through its function as a component of the cell membrane. However, membrane cholesterol also plays a role in the formation and aggregation of amyloid-β. Factors that influence cholesterol metabolism, such as dietary intake, are shown to play a role in late-life cognitive function and the risk of dementia. In conclusion, cholesterol associates with late-life cognitive function, but the association is strongly age-dependent. There is no evidence that treatment with statins in late-life has a beneficial effect on cognitive function.

  7. Dietary plant sterols and cholesterol metabolism.

    PubMed

    Ellegård, Lars H; Andersson, Susan W; Normén, A Lena; Andersson, Henrik A

    2007-01-01

    Plant sterols, naturally occurring in foods of plant origin, reduce cholesterol absorption. Experimental studies show plant sterols to be an important part of the serum-cholesterol lowering effect of certain diets and dietary components. Epidemiological data show that individuals with higher intakes of plant sterols from their habitual diets have lower serum-cholesterol levels. To date, the role of naturally occurring plant sterols for lowering serum cholesterol has probably been underestimated. The consumption of dietary plant sterols should be a part of dietary advice to patients with hypercholesterolemia and the general public for the prevention and management of coronary heart disease.

  8. Impact of cholesterol on disease progression.

    PubMed

    Lin, Chun-Jung; Lai, Cheng-Kuo; Kao, Min-Chuan; Wu, Lii-Tzu; Lo, U-Ging; Lin, Li-Chiung; Chen, Yu-An; Lin, Ho; Hsieh, Jer-Tsong; Lai, Chih-Ho; Lin, Chia-Der

    2015-06-01

    Cholesterol-rich microdomains (also called lipid rafts), where platforms for signaling are provided and thought to be associated with microbe-induced pathogenesis and lead to cancer progression. After treatment of cells with cholesterol disrupting or usurping agents, raft-associated proteins and lipids can be dissociated, and this renders the cell structure nonfunctional and therefore mitigates disease severity. This review focuses on the role of cholesterol in disease progression including cancer development and infectious diseases. Understanding the molecular mechanisms of cholesterol in these diseases may provide insight into the development of novel strategies for controlling these diseases in clinical scenarios.

  9. Crystalline domain structure and cholesterol crystal nucleation in single hydrated DPPC:cholesterol:POPC bilayers.

    PubMed

    Ziblat, Roy; Leiserowitz, Leslie; Addadi, Lia

    2010-07-21

    Grazing incidence X-ray diffraction measurements were performed on single hydrated bilayers and monolayers of DPPC:Cholesterol:POPC at varying concentrations. There are substantial differences in the phase and structure behavior of the crystalline domains formed within the bilayers relative to the corresponding monolayers, due to interactions between the opposing leaflets. Depending on the lipid composition, these interactions led to phase separation, changes in molecular tilt angle, or formation of cholesterol crystals. In monolayers, DPPC and cholesterol form a single crystalline phase at all compositions studied. In bilayers, a second crystalline phase appears when cholesterol levels are increased: domains of cholesterol and DPPC form monolayer thick crystals where each of the lipid leaflets diffracts independently, whereas excess cholesterol forms cholesterol bilayer thick crystals at a DPPC:Chol ratio < 46:54 +/- 2 mol %. The nucleation of the cholesterol crystals occurs at concentrations relevant to the actual cell plasma membrane composition.

  10. Neonatal dietary cholesterol and alleles of cholesterol 7-alpha hydroxylase affect piglet cerebrum weight, cholesterol concentration, and behavior

    USDA-ARS?s Scientific Manuscript database

    This experiment was designed to test the effect of polymorphism in the cholesterol 7-alpha hydroxylase (CYP7) gene locus, and dietary cholesterol (C) on cerebrum C in neonatal pigs fed sow's milk formulas. Thirty-six pigs (18 male and 18 female) genetically selected for high (HG), or low (LG) plasma...

  11. Involvement of free cholesterol and high-density lipoprotein in development and resistance of the preimplantation bovine embryo to heat shock.

    PubMed

    Moss, J I; Garrett, T J; Hansen, P J

    2012-11-01

    Development of the mammalian preimplantation embryo is susceptible to disruption by elevated temperature. The molecular and biochemical bases for developmental, genetic, and other differences in embryonic resistance to heat shock are largely not known. Here we tested the hypothesis that increasing free cholesterol content could improve embryonic resistance to heat shock. Culture of bovine embryos at 41.0°C for 15 h beginning at 30 h after insemination (1- to 2-cell stage) reduced development to the blastocyst stage. Reduction in embryonic cholesterol content by culture with methyl-β-cyclodextrin (MBCD) reduced development. This effect of MBCD could be abrogated in 1 of 2 experiments if the molecule was loaded with cholesterol before addition to culture medium. Even though culture with cholesterol-loaded MBCD increased free cholesterol content, it did not increase resistance of embryos to heat shock. Treatment of embryos with cholesterol-loaded high density lipoprotein (HDL) increased embryonic resistance to heat shock even though it slightly reduced embryo cholesterol content. It is likely that other actions of HDL (e.g., protection from free radicals) were responsible for the thermoprotective properties of this molecule. A final experiment was performed to determine whether the increased resistance of embryos at d 5 of development to heat shock as compared with the 2-cell embryo was due to changes in free cholesterol content. However, there was no significant difference in cholesterol content between 2-cell embryos and d 5 embryos that were > 16 cells in development. In conclusion, raising cholesterol content does not improve embryonic survival in response to heat shock. Depletion of cholesterol, in contrast, reduces competence of embryos to develop to the blastocyst stage. High density lipoprotein is thermoprotective to embryos and probably acts through a mechanism independent of its actions on embryonic content of free cholesterol.

  12. Macrophage heterogeneity and cholesterol homeostasis: classically-activated macrophages are associated with reduced cholesterol accumulation following treatment with oxidized LDL.

    PubMed

    Chu, Eugene M; Tai, Daven C; Beer, Jennifer L; Hill, John S

    2013-02-01

    Macrophages are centrally involved during atherosclerosis development and are the predominant cell type that accumulates cholesterol in the plaque. Macrophages however, are heterogeneous in nature reflecting a variety of microenvironments and different phenotypes may be more prone to contribute towards atherosclerosis progression. Using primary human monocyte-derived macrophages, we sought to evaluate one aspect of atherogenic potential of different macrophage phenotypes by determining their propensity to associate with and accumulate oxidized low density lipoprotein (oxLDL). Classically-activated macrophages treated simultaneously with interferon γ (IFNγ) and tumor necrosis factor α (TNFα) associated with less oxLDL and accumulated less cholesterol compared to untreated controls. The combined treatment of IFNγ and TNFα reduced the mRNA expression of CD36 and the expression of both cell surface CD36 and macrophage scavenger receptor 1 (MSR1) protein. Under oxLDL loaded conditions, IFNγ and TNFα did not reduce macrophage protein expression of the transcription factor peroxisome proliferator-actived receptor γ (PPARγ) which is known to positively regulate CD36 expression. However, macrophages treated with IFNγ attenuated the ability of the PPARγ-specific agonist rosiglitazone from upregulating cell surface CD36 protein expression. Our results demonstrate that the observed reduction of cholesterol accumulation in macrophages treated with IFNγ and TNFα following oxLDL treatment was due at least in part to reduced cell surface CD36 and MSR1 protein expression. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. ACAT inhibitors: the search for novel cholesterol lowering agents.

    PubMed

    Pal, Palash; Gandhi, Hardik; Giridhar, Rajani; Yadav, Mange Ram

    2013-06-01

    Increased level of serum cholesterol (hyperlipidemia) is the most significant risk factor for the development of atherosclerosis. Cholesterol levels are affected by factors such as rate of endogenous cholesterol synthesis, biliary cholesterol excretion and dietary cholesterol absorption. Acyl CoA: Cholesterol O-acyl transferases (ACAT) are a small family of enzymes that catalyze cholesterol esterification and cholesterol absorption in intestinal mucosal cells and maintain the cholesterol homeostasis in the blood. Inhibition of the ACAT enzymes is one of the attractive targets to treat hyperlipidemia. Literature survey shows that structurally diverse compounds possess ACAT inhibitory properties. In this review, a comprehensive presentation of the literature on diverse ACAT inhibitors has been given.

  14. Cholesterol efflux is differentially regulated in neurons and astrocytes: implications for brain cholesterol homeostasis

    PubMed Central

    Chen, Jing; Zhang, Xiaolu; Kusumo, Handojo; Costa, Lucio G.; Guizzetti, Marina

    2012-01-01

    Disruption of cholesterol homeostasis in the central nervous system (CNS) has been associated with neurological, neurodegenerative, and neurodevelopmental disorders. The CNS is a closed system with regard to cholesterol homeostasis, as cholesterol-delivering lipoproteins from the periphery cannot pass the blood-brain-barrier and enter the brain. Different cell types in the brain have different functions in the regulation of cholesterol homeostasis, with astrocytes producing and releasing apolipoprotein E and lipoproteins, and neurons metabolizing cholesterol to 24(S)-hydroxycholesterol. We present evidence that astrocytes and neurons adopt different mechanisms also in regulating cholesterol efflux. We found that in astrocytes cholesterol efflux is induced by both lipid-free apolipoproteins and lipoproteins, while cholesterol removal from neurons is triggered only by lipoproteins. The main pathway by which apolipoproteins induce cholesterol efflux is through ABCA1. By upregulating ABCA1 levels and by inhibiting its activity and silencing its expression, we show that ABCA1 is involved in cholesterol efflux from astrocytes but not from neurons. Furthermore, our results suggest that ABCG1 is involved in cholesterol efflux to apolipoproteins and lipoproteins from astrocytes but not from neurons, while ABCG4, whose expression is much higher in neurons than astrocytes, is involved in cholesterol efflux from neurons but not astrocytes. These results indicate that different mechanisms regulate cholesterol efflux from neurons and astrocytes, reflecting the different roles that these cell types play in brain cholesterol homeostasis. These results are important in understanding cellular targets of therapeutic drugs under development for the treatments of conditions associated with altered cholesterol homeostasis in the CNS. PMID:23010475

  15. Role of cholesterol in Mycobacterium tuberculosis infection.

    PubMed

    Miner, Maurine D; Chang, Jennifer C; Pandey, Amit K; Sassetti, Christopher M; Sherman, David R

    2009-06-01

    Mycobacterium tuberculosis (MTB) acquisition and utilization of nutrients within the host cell is poorly understood, although it has been hypothesized that host lipids probably play an important role in MTB survival. Cholesterol has recently been identified as an important lipid for mycobacterial infection. The mce4 transport system is required for cholesterol import into bacterial cells, and deletion of mce4 locus resulted in severe attenuation in a chronic mouse model of infection. However, it has remained unclear what additional bacterial functions were required for utilization of this sterol. We have found that the igr locus, which was previously found essential for intracellular growth and virulence of MTB, is required for cholesterol metabolism: igr-deficient bacteria cannot grow using cholesterol as a primary carbon source. The growth-inhibitory effect of cholesterol in vitro depends on cholesterol import, as the delta igr mutant growth defect during the early phase of disease is completely suppressed by mutating mce4, implicating cholesterol intoxication as the primary mechanism of attenuation. We conclude that M. tuberculosis metabolizes cholesterol throughout the course of infection, and that degradation of this sterol is crucial for bacterial persistence.

  16. Cholesterol: An Achilles' Heel for Glioblastoma?

    PubMed

    An, Zhenyi; Weiss, William A

    2016-11-14

    In this issue of Cancer Cell, Villa et al. report that survival of glioblastoma cells is dependent on uptake of cholesterol. A synthetic agonist of the Liver X receptor depleted cholesterol in GBM cells, slowing growth of GBM xenografts.

  17. What Do My Cholesterol Levels Mean?

    MedlinePlus

    ... to write your own questions for the next time you see your healthcare provider. For example: How can I reduce my cholesterol? How often should I have my cholesterol checked? ©2015, American Heart Association Multi-language Fact Sheet Topics Heart-related Conditions What is ...

  18. Cholesterol-lowering nutraceuticals and functional foods.

    PubMed

    Chen, Zhen-Yu; Jiao, Rui; Ma, Ka Ying

    2008-10-08

    Epidemiological studies have demonstrated that elevated levels of plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) are the major risk factors for coronary heart disease (CHD), whereas high concentrations of plasma high-density lipoprotein cholesterol (HDL-C) and a low ratio of TC to HDL-C are protective against CHD. A relationship between plasma TC and the risk of CHD is well established at concentrations above 240 mg/dL. In addition to the use of three main classes of cholesterol-lowering medications, including HMG-CoA reductase inhibitors, anion-exchange resins, and fibrates, a nutritionally balanced diet that reduces saturated fat and cholesterol intake has traditionally been the first goal of dietary therapy in lowering plasma TC. In recent years, nutraceuticals and functional foods have attracted much interest as possible alternative therapies for lowering plasma TC, especially for hypercholesterolemia patients, whose blood cholesterol level is marginally high (200-240 mg/dL) but not high enough to warrant the prescription of cholesterol-lowering medications. This review summarizes the findings of recent studies on the production, application, efficacy, and mechanisms of popular cholesterol-lowering nutraceuticals and functional foods.

  19. MicroRNA-223 coordinates cholesterol homeostasis

    PubMed Central

    Vickers, Kasey C.; Landstreet, Stuart R.; Levin, Michael G.; Shoucri, Bassem M.; Toth, Cynthia L.; Taylor, Robert C.; Palmisano, Brian T.; Tabet, Fatiha; Cui, Huanhuan L.; Rye, Kerry-Anne; Sethupathy, Praveen; Remaley, Alan T.

    2014-01-01

    MicroRNAs (miRNAs) regulate a wide variety of biological processes and contribute to metabolic homeostasis. Here, we demonstrate that microRNA-223 (miR-223), an miRNA previously associated with inflammation, also controls multiple mechanisms associated with cholesterol metabolism. miR-223 promoter activity and mature levels were found to be linked to cellular cholesterol states in hepatoma cells. Moreover, hypercholesterolemia was associated with increased hepatic miR-223 levels in athero-prone mice. miR-223 was found to regulate high-density lipoprotein-cholesterol (HDL-C) uptake, through direct targeting and repression of scavenger receptor BI, and to inhibit cholesterol biosynthesis through the direct repression of sterol enzymes 3-hydroxy-3-methylglutaryl-CoA synthase 1 and methylsterol monooxygenase 1 in humans. Additionally, miR-223 was found to indirectly promote ATP-binding cassette transporter A1 expression (mRNA and protein) through Sp3, thereby enhancing cellular cholesterol efflux. Finally, genetic ablation of miR-223 in mice resulted in increased HDL-C levels and particle size, as well as increased hepatic and plasma total cholesterol levels. In summary, we identified a critical role for miR-223 in systemic cholesterol regulation by coordinated posttranscriptional control of multiple genes in lipoprotein and cholesterol metabolism. PMID:25246565

  20. Arctigenin promotes cholesterol efflux from THP-1 macrophages through PPAR-γ/LXR-α signaling pathway.

    PubMed

    Xu, Xiaolin; Li, Qian; Pang, Liewen; Huang, Guoqian; Huang, Jiechun; Shi, Meng; Sun, Xiaotian; Wang, Yiqing

    2013-11-15

    Cholesterol efflux from macrophages is a critical mechanism to prevent the development of atherosclerosis. Here, we sought to investigate the effects of arctigenin, a bioactive component of Arctium lappa, on the cholesterol efflux in oxidized low-density lipoprotein (oxLDL)-loaded THP-1 macrophages. Our data showed that arctigenin significantly accelerated apolipoprotein A-I- and high-density lipoprotein-induced cholesterol efflux in both dose- and time-dependent manners. Moreover, arctigenin treatment enhanced the expression of ATP binding cassette transporter A1 (ABCA1), ABCG1, and apoE, all of which are key molecules in the initial step of cholesterol efflux, at both mRNA and protein levels. Arctigenin also caused a concentration-dependent elevation in the expression of peroxisome proliferator-activated receptor-gamma (PPAR-γ) and liver X receptor-alpha (LXR-α). The arctigenin-mediated induction of ABCA1, ABCG1, and apoE was abolished by specific inhibition of PPAR-γ or LXR-α using small interfering RNA technology. Our results collectively indicate that arctigenin promotes cholesterol efflux in oxLDL-loaded THP-1 macrophages through upregulation of ABCA1, ABCG1 and apoE, which is dependent on the enhanced expression of PPAR-γ and LXR-α. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Prosopis farcta beans increase HDL cholesterol and decrease LDL cholesterol in ostriches (Struthio camelus).

    PubMed

    Omidi, Arash; Ansari nik, Hossein; Ghazaghi, Mahmood

    2013-02-01

    Ten blue-neck male ostriches (Struthio camelus) were fed Prosopis farcta beans throughout a 30-day experiment. Blood samples were collected from ostriches on days 0 and 30 to measure levels of high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride, total serum protein, albumin, globulin, cholesterol, calcium, inorganic phosphorus, the activity of aspartate aminotransferase, alanine aminotransferase, and γ-glutamyl transferase (γ-GT). From days 0 to 30, HDL cholesterol, total protein, and globulins levels increased significantly whereas LDL cholesterol, inorganic phosphorus, and γ-GT activity decreased significantly.

  2. Cholesterol granulomas in three meerkats (Suricata suricatta).

    PubMed

    Sladky, K K; Dalldorf, F G; Steinberg, H; Wright, J F; Loomis, M R

    2000-11-01

    Cholesterol granulomas are uncommon pathologic lesions in animals, although they are important intracranial tumors in humans. This report describes cholesterol granulomas associated with multiple organ systems of three captive meerkats. In the most severe case, meerkat No. 1, the pathologic behavior of the cholesterol granuloma was unique in that it appeared to locally invade the cerebrum and calvarium, possibly contributing to neurological deficits observed antemortem. A review of other meerkat necropsies revealed incidental, asymptomatic cholesterol granulomas in organs of two other individuals, meerkat Nos. 2 and 3. Histologically, all lesions were composed of cholesterol clefts admixed with large, foamy macrophages containing hemosiderin, multinucleated giant cells, lymphocytes, plasma cells, and foci of mineralization. Hypercholesterolemia was documented in two of the three meerkats.

  3. Cholesterol-lowering effect of plant sterols.

    PubMed

    AbuMweis, Suhad S; Jones, Peter J H

    2008-12-01

    Plant sterols are plant components that have a chemical structure similar to cholesterol except for the addition of an extra methyl or ethyl group; however, plant sterol absorption in humans is considerably less than that of cholesterol. In fact, plant sterols reduce cholesterol absorption and thus reduce circulating levels of cholesterol. Earlier studies that have tested the efficacy of plant sterols as cholesterol-lowering agents incorporated plant sterols into fat spreads. Later on, plant sterols were added to other food matrices, including juices, nonfat beverages, milk and yogurt, cheese, meat, croissants and muffins, and cereal and chocolate bars. The beneficial physiologic effects of plant sterols could be further enhanced by combining them with other beneficial substances, such as olive and fish oils, fibers, and soy proteins, or with exercise. The addition of plant sterols to the diet is suggested by health experts as a safe and effective way to reduce the risk of coronary heart disease.

  4. Analysis of cholesterol trafficking with fluorescent probes

    PubMed Central

    Maxfield, Frederick R.; Wüstner, Daniel

    2013-01-01

    Cholesterol plays an important role in determining the biophysical properties of biological membranes, and its concentration is tightly controlled by homeostatic processes. The intracellular transport of cholesterol among organelles is a key part of the homeostatic mechanism, but sterol transport processes are not well understood. Fluorescence microscopy is a valuable tool for studying intracellular transport processes, but this method can be challenging for lipid molecules because addition of a fluorophore may alter the properties of the molecule greatly. We discuss the use of fluorescent molecules that can bind to cholesterol to reveal its distribution in cells. We also discuss the use of intrinsically fluorescent sterols that closely mimic cholesterol, as well as some minimally modified fluorophore-labeled sterols. Methods for imaging these sterols by conventional fluorescence microscopy and by multiphoton microscopy are described. Some label-free methods for imaging cholesterol itself are also discussed briefly. PMID:22325611

  5. Characteristics and Functional Relevance of Apolipoprotein-A1 and Cholesterol Binding in Mammary Gland Tissues and Epithelial Cells

    PubMed Central

    Ontsouka, Edgar Corneille; Huang, Xiao; Stieger, Bruno; Albrecht, Christiane

    2013-01-01

    Cholesterol in milk is derived from the circulating blood through a complex transport process involving the mammary alveolar epithelium. Details of the mechanisms involved in this transfer are unclear. Apolipoprotein-AI (apoA-I) is an acceptor of cellular cholesterol effluxed by the ATP-binding cassette (ABC) transporter A1 (ABCA1). We aimed to 1) determine the binding characteristics of 125I-apoA-I and 3H-cholesterol to enriched plasma membrane vesicles (EPM) isolated from lactating and non-lactating bovine mammary glands (MG), 2) optimize the components of an in vitro model describing cellular 3H-cholesterol efflux in primary bovine mammary epithelial cells (MeBo), and 3) assess the vectorial cholesterol transport in MeBo using Transwell® plates. The amounts of isolated EPM and the maximal binding capacity of 125I-apoA-I to EPM differed depending on the MG’s physiological state, while the kinetics of 3H-cholesterol and 125I-apoA-I binding were similar. 3H-cholesterol incorporated maximally to EPM after 25±9 min. The time to achieve the half-maximum binding of 125I-apoA-I at equilibrium was 3.3±0.6 min. The dissociation constant (KD) of 125I-apoA-I ranged between 40–74 nmol/L. Cholesterol loading to EPM increased both cholesterol content and 125I-apoA-I binding. The ABCA1 inhibitor Probucol displaced 125I-apoA-I binding to EPM and reduced 3H-cholesterol efflux in MeBo. Time-dependent 3H-cholesterol uptake and efflux showed inverse patterns. The defined binding characteristics of cholesterol and apoA-I served to establish an efficient and significantly shorter cholesterol efflux protocol that had been used in MeBo. The application of this protocol in Transwell® plates with the upper chamber mimicking the apical (milk-facing) and the bottom chamber corresponding to the basolateral (blood-facing) side of cells showed that the degree of 3H-cholesterol efflux in MeBo differed significantly between the apical and basolateral aspects. Our findings support the

  6. Characteristics and functional relevance of apolipoprotein-A1 and cholesterol binding in mammary gland tissues and epithelial cells.

    PubMed

    Ontsouka, Edgar Corneille; Huang, Xiao; Stieger, Bruno; Albrecht, Christiane

    2013-01-01

    Cholesterol in milk is derived from the circulating blood through a complex transport process involving the mammary alveolar epithelium. Details of the mechanisms involved in this transfer are unclear. Apolipoprotein-AI (apoA-I) is an acceptor of cellular cholesterol effluxed by the ATP-binding cassette (ABC) transporter A1 (ABCA1). We aimed to 1) determine the binding characteristics of (125)I-apoA-I and (3)H-cholesterol to enriched plasma membrane vesicles (EPM) isolated from lactating and non-lactating bovine mammary glands (MG), 2) optimize the components of an in vitro model describing cellular (3)H-cholesterol efflux in primary bovine mammary epithelial cells (MeBo), and 3) assess the vectorial cholesterol transport in MeBo using Transwell(®) plates. The amounts of isolated EPM and the maximal binding capacity of (125)I-apoA-I to EPM differed depending on the MG's physiological state, while the kinetics of (3)H-cholesterol and (125)I-apoA-I binding were similar. (3)H-cholesterol incorporated maximally to EPM after 25±9 min. The time to achieve the half-maximum binding of (125)I-apoA-I at equilibrium was 3.3±0.6 min. The dissociation constant (KD) of (125)I-apoA-I ranged between 40-74 nmol/L. Cholesterol loading to EPM increased both cholesterol content and (125)I-apoA-I binding. The ABCA1 inhibitor Probucol displaced (125)I-apoA-I binding to EPM and reduced (3)H-cholesterol efflux in MeBo. Time-dependent (3)H-cholesterol uptake and efflux showed inverse patterns. The defined binding characteristics of cholesterol and apoA-I served to establish an efficient and significantly shorter cholesterol efflux protocol that had been used in MeBo. The application of this protocol in Transwell(®) plates with the upper chamber mimicking the apical (milk-facing) and the bottom chamber corresponding to the basolateral (blood-facing) side of cells showed that the degree of (3)H-cholesterol efflux in MeBo differed significantly between the apical and basolateral aspects

  7. HDL-apolipoprotein A-I exchange is independently associated with cholesterol efflux capacity

    PubMed Central

    Borja, Mark S.; Ng, Kit F.; Irwin, Angela; Hong, Jaekyoung; Wu, Xing; Isquith, Daniel; Zhao, Xue-Qiao; Prazen, Bryan; Gildengorin, Virginia; Oda, Michael N.; Vaisar, Tomáš

    2015-01-01

    HDL is the primary mediator of cholesterol mobilization from the periphery to the liver via reverse cholesterol transport (RCT). A critical first step in this process is the uptake of cholesterol from lipid-loaded macrophages by HDL, a function of HDL inversely associated with prevalent and incident cardiovascular disease. We hypothesized that the dynamic ability of HDL to undergo remodeling and exchange of apoA-I is an important and potentially rate-limiting aspect of RCT. In this study, we investigated the relationship between HDL-apoA-I exchange (HAE) and serum HDL cholesterol (HDL-C) efflux capacity. We compared HAE to the total and ABCA1-specific cholesterol efflux capacity of 77 subjects. We found that HAE was highly correlated with both total (r = 0.69, P < 0.0001) and ABCA1-specific (r = 0.47, P < 0.0001) efflux, and this relationship remained significant after adjustment for HDL-C or apoA-I. Multivariate models of sterol efflux capacity indicated that HAE accounted for approximately 25% of the model variance for both total and ABCA1-specific efflux. We conclude that the ability of HDL to exchange apoA-I and remodel, as measured by HAE, is a significant contributor to serum HDL efflux capacity, independent of HDL-C and apoA-I, indicating that HDL dynamics are an important factor in cholesterol efflux capacity and likely RCT. PMID:26254308

  8. Cholesterol overloading leads to hepatic L02 cell damage through activation of the unfolded protein response.

    PubMed

    Li, Qi; Liu, Zhiguo; Guo, Jianli; Chen, Jiangyuan; Yang, Pu; Tian, Jun; Sun, Jun; Zong, Yiqiang; Qu, Shen

    2009-10-01

    Reported data indicate that cholesterol loading in the liver can cause hepatic injury. To explore the possible mechanisms of cell damage resulting from cholesterol overloading in hepatocytes, cell apoptosis, the unfolded protein response (UPR) and the correlation between them were assessed in the cholesterol-overloaded normal human hepatic cell line L02. L02 cells were incubated with 200 microg/ ml of low density lipoprotein (LDL) for 24 h with or without 20 microg/ml 58035, an inhibitor of acyl-CoA:cholesterol acyltransferase (ACAT). In the LDL+58035 group, the intracellular cholesterol level was dramatically increased, which was measured by an enzymatic combined high performance liquid chromatography assay. Expression of immunoglobulin-binding protein, X-box binding protein 1, activating transcription factor 6, activating transcription factor 4, CCAAT/enhancer-binding protein homologous protein-10, markers of endoplasmic reticulum stress (ERS)/ UPR, were up-regulated as determined using reverse transcription-polymerase chain reaction (RT-PCR) or Western blot analysis. The rate of cell apoptic death increased 21.3+/-2.4%. Meanwhile, the active caspase-3 protein expression was increased 8.4-fold compared to the active caspase-3 protein expression in the controls. Furthermore, 4-phenylbutyric acid, an inhibitor of UPR, partly reduced cell apoptosis and activation of caspase-3. This study suggests that cholesterol overloading in hepatic L02 cells induces ERS and activates the UPR which, in part, leads to the apoptotic damage of cells.

  9. Fish protein decreases serum cholesterol in rats by inhibition of cholesterol and bile acid absorption.

    PubMed

    Hosomi, Ryota; Fukunaga, Kenji; Arai, Hirofumi; Kanda, Seiji; Nishiyama, Toshimasa; Yoshida, Munehiro

    2011-05-01

    Fish protein has been shown to decrease serum cholesterol content by inhibiting absorption of cholesterol and bile acid in laboratory animals, though the mechanism underlying this effect is not yet fully understood. The purpose of this study was to elucidate the mechanism underlying the inhibition of cholesterol and bile acid absorption following fish protein intake. Male Wistar rats were divided into 2 dietary groups of 7 rats each, 1 group receiving a diet consisting of 20% casein and the other receiving a diet consisting of 10% casein and 10% fish protein. Both experimental diets also contained 0.5% cholesterol and 0.1% sodium cholate. After the rats had been on their respective diets for 4 wk, their serum and liver cholesterol contents and fecal cholesterol, bile acid, and nitrogen excretion contents were measured. Fish protein consumption decreased serum and liver cholesterol content and increased fecal cholesterol and bile acid excretion and simultaneously increased fecal nitrogen excretion. In addition, fish protein hydrolyzate prepared by in vitro digestion had lower micellar solubility of cholesterol and higher binding capacity for bile acids compared with casein hydrolyzate. These results suggest that the hypocholesterolemic effect of fish protein is mediated by increased fecal cholesterol and bile acid excretion, which is due to the digestion products of fish protein having reduced micellar solubility of cholesterol and increased bile acid binding capacity.

  10. Cholesterol Accumulation in CD11c(+) Immune Cells Is a Causal and Targetable Factor in Autoimmune Disease.

    PubMed

    Ito, Ayaka; Hong, Cynthia; Oka, Kazuhiro; Salazar, Jon V; Diehl, Cody; Witztum, Joseph L; Diaz, Mercedes; Castrillo, Antonio; Bensinger, Steven J; Chan, Lawrence; Tontonoz, Peter

    2016-12-20

    Liver X receptors (LXRs) are regulators of cholesterol metabolism that also modulate immune responses. Inactivation of LXR α and β in mice leads to autoimmunity; however, how the regulation of cholesterol metabolism contributes to autoimmunity is unclear. Here we found that cholesterol loading of CD11c(+) cells triggered the development of autoimmunity, whereas preventing excess lipid accumulation by promoting cholesterol efflux was therapeutic. LXRβ-deficient mice crossed to the hyperlipidemic ApoE-deficient background or challenged with a high-cholesterol diet developed autoantibodies. Cholesterol accumulation in lymphoid organs promoted T cell priming and stimulated the production of the B cell growth factors Baff and April. Conversely, B cell expansion and the development of autoantibodies in ApoE/LXR-β-deficient mice was reversed by ApoA-I expression. These findings implicate cholesterol imbalance as a contributor to immune dysfunction and suggest that stimulating HDL-dependent reverse cholesterol transport could be beneficial in the setting of autoimmune disease. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Dietary cholesterol and the origin of cholesterol in the brain of developing rats.

    PubMed

    Edmond, J; Korsak, R A; Morrow, J W; Torok-Both, G; Catlin, D H

    1991-09-01

    Milk substitutes containing cholesterol at concentrations lower, equal to or greater than the concentrations found in natural rat milk were fed to artificially reared rat pups from 5 d until 15 or 16 d after birth. Pups reared by their mother served as controls. In one experiment, D7-cholesterol was fed in the milk at four different concentrations. The purpose of the study was to determine whether cholesterol in milk influenced growth and the sterol composition of brain over the period of its most rapid accumulation in this organ. We found that body and brain weights were not different, irrespective of the concentration of cholesterol in the milk substitutes. High concentrations of cholesterol in milk caused a significant increase in cholesterol in liver and plasma, whereas the concentration of cholesterol in brain was not different from the concentration in the brain of controls. The amounts of D7-cholesterol in lung and liver, and in plasma and RBC that pass the brain, were consistent with the concentration fed in the milk and approached 70% of the total content of cholesterol in these organs at the highest concentration fed. Brain, by contrast, contained very small amounts of D7-cholesterol, which could readily be attributed to D7-cholesterol associated with the vascular system of the blood-brain barrier. We found that the sterol composition of brain is not influenced by the concentration of cholesterol in milk and that cholesterol exogenous to brain, even in a hypercholesterolemic condition, does not gain entry to the brain. We conclude that the brain biosynthesizes de novo all the cholesterol it requires.

  12. Cholesterol-Lowering Supplements: Lower Your Numbers without Prescription Medication

    MedlinePlus

    ... cholesterol and LDL cholesterol May cause nausea, indigestion, gas, diarrhea or constipation; may be ineffective if you take ezetimibe (Zetia), a prescription cholesterol medication Soy protein as a substitute for other high-fat protein sources May reduce ...

  13. A computational and functional study elicits the ameliorating effect of the Chinese herbal formula Huo Luo Xiao Ling Dan on experimental ischemia-induced myocardial injury in rats via inhibition of apoptosis

    PubMed Central

    Han, Xiang-Dong; Zhou, Zhi-Wei; Yang, Wei; Ye, Hang-Cheng; Xu, Ying-Zi; Huang, Yun-Feng; Zhang, Tong; Zhou, Shu-Feng

    2015-01-01

    rise/descent of left ventricular pressure levels. Administration of HLXLD significantly ameliorated coronary artery ligation-induced tissue damage in the left ventricle, with restored arrangement of myocardial fibers and recovered myoplasm in rats. Furthermore, HLXLD markedly increased the expression level of Bcl-2 but decreased the level of cleaved caspase 3. Taken together, administration of HLXLD attenuated acute myocardial ischemia-induced damage in cardiomyocytes and inhibited apoptotic death of cardiomyocytes, thereby exerting a cardioprotective effect in rats with IHD. These findings suggest that HLXLD may represent a promising herbal formula for the treatment of cardiovascular disease by counteracting apoptotic cell death via multiple active compounds. More studies are warranted to fully elucidate the mechanisms of action, identify the therapeutic targets, and validate the efficacy and safety of HLXLD in the treatment of IHD. PMID:25733819

  14. Cholesterol trafficking-related serum lipoprotein functions in children with cholesteryl ester storage disease.

    PubMed

    Zimetti, Francesca; Favari, Elda; Cagliero, Paola; Adorni, Maria Pia; Ronda, Nicoletta; Bonardi, Renato; Gomaraschi, Monica; Calabresi, Laura; Bernini, Franco; Guardamagna, Ornella

    2015-10-01

    Serum lipoproteins influence cell cholesterol content by delivering and removing cholesterol to/from cells, functions mainly exerted by LDL and HDL, respectively. Especially in the case of HDL, structure and composition are crucial for function, beyond serum levels. Cholesteryl ester storage disease (CESD) is caused by LIPA gene mutations and reduced activity of lysosomal acid lipase (LAL), the enzyme responsible for hydrolysis of cholesteryl esters and TG. CESD patients typically present dyslipidaemia, liver damage and premature atherosclerosis. The objective of this work was to evaluate serum HDL cholesterol efflux capacity (CEC) and serum cholesterol loading capacity (CLC) in CESD pediatric patients and to study lipoprotein qualitative modifications. HDL CEC was evaluated by radioisotopic techniques, serum CLC was measured by a fluorimetric assay, HDL subclasses were determined by two-dimensional electrophoresis. CESD patients (n = 3) displayed on average increased LDL cholesterol (+163%; p = 0.019), TG (+203; p = 0.012), phospholipids (+40%; p = 0.024) and lower HDL cholesterol (-57%; p = 0.012) compared to controls (n = 9). CESD HDL CEC was impaired both as a whole (average reduction of 26%; p < 0.0001) and with respect to specific membrane cholesterol transporters (-23% for aqueous diffusion; p = 0.005; -32% for ABCA1-efflux; p = 0.0002; -60% for SR-BI-efflux; p < 0.0001; -42% for ABCG1-efflux p = 0.0003). A marked reduction in the pre-β HDL concentration (-69%; p = 0.012) was detected. Finally, CESD serum CLC was significantly increased (+21%; p = 0.0007). These new data demonstrate that the pro-atherogenic modifications of serum include disturbances in lipoprotein functions involved in cell cholesterol homeostasis occurring from very early age in CESD patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Effect of potato ethanol residue on rat plasma cholesterol levels.

    PubMed

    Hashimoto, Naoto; Shinomiya, Noriyuki; Saito, Katsuichi; Noda, Takahiro; Han, Kyu-Ho; Fukushima, Michihiro

    2013-01-01

    We investigated the cholesterol-lowering effect of a potato ethanol residue (PER). The plasma cholesterol levels excluding high-density lipoprotein cholesterol were lower in the rats given a PER-containing diet for 6 weeks than in the control group, whereas the fecal cholesterol levels were higher. These results suggest that PER partially reduced plasma cholesterol levels via excretion of cholesterol into the feces.

  16. Physiological and pathological implications of cholesterol.

    PubMed

    Cortes, Victor A; Busso, Dolores; Maiz, Alberto; Arteaga, Antonio; Nervi, Flavio; Rigotti, Attilio

    2014-01-01

    Cholesterol has evolved to fulfill sophisticated biophysical, cell signaling and endocrine requirements of animal systems. At a cellular level, cholesterol is found in membranes, where it increases both bilayer stiffness and impermeability to water and ions. Furthermore, cholesterol is integrated into specialized lipid-protein membrane microdomains with critical topographical and signaling functions. At an organismal level, cholesterol is the precursor for all steroid hormones, including gluco- and mineralo-corticoids, sex hormones and vitamin D, all of which regulate carbohydrate, sodium, reproductive and bone homeostasis, respectively. This sterol is also the precursor for bile acids, which are important for intestinal absorption of dietary lipids as well as energy and glucose metabolic regulation. Importantly, complex mechanisms maintain cholesterol within physiological ranges and the disregulation of these mechanisms results in embryonic or adult diseases, caused by either excessive or reduced tissue cholesterol levels. The causative role of cholesterol in these diseases has been demonstrated by diverse genetic and pharmacologic animal models that are commented in this review.

  17. Cholesterol Asymmetry in Synaptic Plasma Membranes

    PubMed Central

    Wood, W. Gibson; Igbavboa, Urule; Müller, Walter E.; Eckert, Gunter P.

    2010-01-01

    Lipids are essential for the structural and functional integrity of membranes. Membrane lipids are not randomly distributed but are localized in different domains. A common characteristic of these membrane domains is their association with cholesterol. Lipid rafts and caveolae are examples of cholesterol enriched domains, which have attracted keen interest. However, two other important cholesterol domains are the exofacial and cytofacial leaflets of the plasma membrane. The two leaflets that make up the bilayer differ in their fluidity, electrical charge, lipid distribution, and active sites of certain proteins. The synaptic plasma membrane (SPM) cytofacial leaflet contains over 85% of the total SPM cholesterol as compared with the exofacial leaflet. This asymmetric distribution of cholesterol is not fixed or immobile but can be modified by different conditions in vivo: 1) chronic ethanol consumption; 2) statins; 3) aging; and 4) apoE isoform. Several potential candidates have been proposed as mechanisms involved in regulation of SPM cholesterol asymmetry: apoE, low-density-lipoprotein receptor, sterol carrier protein-2, fatty acid binding proteins, polyunsaturated fatty acids, p-glycoprotein and caveolin-1. This review examines cholesterol asymmetry in SPM, potential mechanisms of regulation and impact on membrane structure and function. PMID:21214553

  18. Biliary lipids and cholesterol gallstone disease

    PubMed Central

    Wang, David Q-H.; Cohen, David E.; Carey, Martin C.

    2009-01-01

    Biliary lipids are a family of four dissimilar molecular species consisting of a mixture of bile salts (substituted cholanoic acids), phospholipids, mostly (>96%) diacylphosphatidylcholines, unesterified cholesterol, and bilirubin conjugates known trivially as lipopigments. The primary pathophysiological defect in cholesterol gallstone disease is hypersecretion of hepatic cholesterol into bile with less frequent hyposecretion of bile salts and/or phospholipids. Several other gallbladder abnormalities contribute and include hypomotility, immune-mediated inflammation, hypersecretion of gelling mucins, and accelerated phase transitions; there is also reduced intestinal motility that augments “secondary” bile salt synthesis by the anaerobic microflora. Cholesterol nucleation is initiated when unilamellar vesicles of cholesterol plus biliary phospholipids fuse to form multilamellar vesicles. From these “plate-like” cholesterol monohydrate crystals, the building blocks of macroscopic stones are nucleated heterogeneously by mucin gel. Multiple Lith gene loci have been identified in inbred mice, paving the way for discovery of an ever-increasing number of LITH genes in humans. Because of the frequency of the metabolic syndrome today, insulin resistance and LITH genes all interact with a number of environmental cholelithogenic factors to cause the gallstone phenotype. This review summarizes current concepts of the physical-chemical state of biliary lipids in health and in lithogenic bile and outlines the molecular, genetic, hepatic, and cholecystic factors that underlie the pathogenesis of cholesterol gallstones. PMID:19017613

  19. Tau pathology induces intraneuronal cholesterol accumulation.

    PubMed

    Glöckner, Frauke; Ohm, Thomas G

    2014-09-01

    Epidemiologic and experimental data suggest the involvement of cholesterol metabolism in the development and progression of Alzheimer disease and Niemann-Pick type C disease, but not of frontotemporal dementias. In these 3 neurodegenerative diseases, however, protein tau hyperphosphorylation and aggregation into neurofibrillary tangles are observed. To elucidate the relationship between cholesterol and tau, we compared sterol levels of neurons burdened with neurofibrillary tangles with those of their unaffected neighbors using semiquantitative filipin fluorescence microscopy in mice expressing P301L mutant human tau (a well-described model of FTDP-17) and in P301L transgenic mice lacking apolipoprotein E (the major cholesterol transporter in the brain). Cellular unesterified cholesterol was higher in neurons affected by tau pathology irrespective of apolipoprotein E deficiency. This argues for an impact of tau pathology on cellular cholesterol homeostasis. We suggest that there is a bidirectional mode of action: Disturbances in cellular cholesterol metabolism may promote tau pathology, but tau pathology may also alter neuronal cholesterol homeostasis; once it is established, a vicious cycle may promote neurofibrillary tangle formation.

  20. Proteins and cholesterol-rich domains.

    PubMed

    Epand, Richard M

    2008-01-01

    Biological membranes are composed of many molecular species of lipids and proteins. These molecules do not mix ideally. In the plane of the membrane components are segregated into domains that are enriched in certain lipids and proteins. Cholesterol is a membrane lipid that is not uniformly distributed in the membrane. Proteins play an important role in determining cholesterol distribution. Certain types of protein lipidation are known to cause the lipoprotein to sequester with cholesterol and to stabilize cholesterol-rich domains. However, proteins that are excluded from such domains also contribute to the redistribution of cholesterol. One of the motifs that favor interaction with cholesterol is the CRAC motif. The role of the CRAC motif of the gp41 fusogenic protein of HIV is discussed. The distribution of the multianionic lipid, phosphatidylinositol(4,5)bis-phosphate (PtnIns(4,5)P2), is also not uniform in cell membranes. This lipid has several functions in the cell, including a morphological role in determining the sites of attachment of the actin cytoskeleton to the plasma membrane. PtnIns(4,5)P2 is sequestered by proteins having clusters of cationic residues in their sequence. Certain proteins containing cationic clusters also contain moieties such as myristoylation or a CRAC segment that would also endow them with the ability to sequester to a cholesterol-rich domain. These proteins interact with PtnIns(4,5)P2 in a cholesterol-dependent manner forming domains that are enriched in both cholesterol and in PtnIns(4,5)P2 but can also be distinct from liquid-ordered raft-like domains.

  1. Cellular Cholesterol Transport Proteins in Diabetic Nephropathy

    PubMed Central

    Tsun, Joseph G. S.; Yung, Susan; Chau, Mel K. M.; Shiu, Sammy W. M.; Chan, Tak Mao; Tan, Kathryn C. B.

    2014-01-01

    Background Lipid accumulation has been shown to accelerate renal injury, and the intracellular accumulation of lipids may be caused by alterations in synthesis as well as lipid uptake and efflux. We have investigated the role of cellular cholesterol transport proteins including adenosine triphosphate binding cassette transporter A1 (ABCA1), G1 (ABCG1) and scavenger receptor class B type I (SR-BI) in diabetic nephropathy. Methods Protein expression and the ability to mediate cholesterol efflux of ABCA1, ABCG1 and SR-BI was determined in human renal mesangial cells and proximal tubular epithelial cells cultured under normal or high glucose conditions. Renal expression of these cholesterol transporters was examined in a murine model of streptozotocin-induced type 1 diabetes. Results ABCA1, ABCG1 and SR-BI were expressed in both human renal mesangial cells and proximal tubular epithelial cells, and mediated cholesterol efflux to apolipoprotein AI and HDL. In vitro, hyperglycemia reduced the expression and the ability to mediate cholesterol efflux of all three cholesterol transporters (p<0.05). In vivo studies showed that intra-renal accumulation of lipids was increased in diabetic mice, particularly in mice with nephropathy. This was associated with a significant reduction in the expression of ABCA1, ABCG1 and SR-BI in the kidneys. These changes were already seen in diabetic mice without nephropathy and preceded the development of nephropathy. Diabetic mice with nephropathy had the lowest level of these cholesterol transporters. Conclusion Inducing diabetes with streptozotocin significantly reduced renal expression of ABCA1, ABCG1 and SR-BI. Defects in cholesterol export pathway in renal cells could therefore promote cholesterol accumulation and might contribute to the development of diabetic nephropathy. PMID:25181357

  2. Genetic therapies to lower cholesterol.

    PubMed

    Khoo, Bernard

    2015-01-01

    This review surveys the state-of-the-art in genetic therapies for familial hypercholesterolaemia (FH), caused most commonly by mutations in the LDL receptor (LDLR) gene. FH manifests as highly elevated low density lipoprotein (LDL) cholesterol levels and consequently accelerated atherosclerosis. Modern pharmacological therapies for FH are insufficiently efficacious to prevent premature cardiovascular disease, can cause significant adverse effects and can be expensive. Genetic therapies for FH have been mooted since the mid 1990s but gene replacement strategies using viral vectors have so far been unsuccessful. Other strategies involve knocking down the expression of Apolipoprotein B100 (APOB100) and the protease PCSK9 which designates LDLR for degradation. The antisense oligonucleotide mipomersen, which knocks down APOB100, is currently marketed (with restrictions) in the USA, but is not approved in Europe due to its adverse effects. To address this problem, we have devised a novel therapeutic concept, APO-skip, which is based on modulation of APOB splicing, and which has the potential to deliver a cost-effective, efficacious and safe therapy for FH.

  3. Raising HDL cholesterol in women.

    PubMed

    Eapen, Danny J; Kalra, Girish L; Rifai, Luay; Eapen, Christina A; Merchant, Nadya; Khan, Bobby V

    2010-08-09

    High-density lipoprotein cholesterol (HDL-C) concentration is essential in the determination of coronary heart disease (CHD) risk in women. This is especially true in the postmenopausal state, where lipid profiles and CHD risk mimic that of age-matched men. Thus, interventions designed to reduce CHD risk by raising HDL-C levels may have particular significance during the transition to menopause. This review discusses HDL-C-raising therapies and the role of HDL in the primary prevention of CHD in women. Lifestyle-based interventions such as dietary change, aerobic exercise regimens, and smoking cessation are initial steps that are effective in raising HDL-C, and available data suggest women respond similarly to men with these interventions. When combined with pharmacotherapy, the effects of these lifestyle alterations are further amplified. Though studies demonstrating gender-specific differences in therapy are limited, niacin continues to be the most effective agent in raising HDL-C levels, especially when used in combination with fibrate or statin therapy. Emerging treatments such as HDL mimetic therapy show much promise in further raising HDL-C levels and improving cardiovascular outcomes.

  4. Cholesterol Depletion from a Ceramide/Cholesterol Mixed Monolayer: A Brewster Angle Microscope Study

    PubMed Central

    Mandal, Pritam; Noutsi, Pakiza; Chaieb, Sahraoui

    2016-01-01

    Cholesterol is crucial to the mechanical properties of cell membranes that are important to cells’ behavior. Its depletion from the cell membranes could be dramatic. Among cyclodextrins (CDs), methyl beta cyclodextrin (MβCD) is the most efficient to deplete cholesterol (Chol) from biomembranes. Here, we focus on the depletion of cholesterol from a C16 ceramide/cholesterol (C16-Cer/Chol) mixed monolayer using MβCD. While the removal of cholesterol by MβCD depends on the cholesterol concentration in most mixed lipid monolayers, it does not depend very much on the concentration of cholesterol in C16-Cer/Chol monolayers. The surface pressure decay during depletion were described by a stretched exponential that suggested that the cholesterol molecules are unable to diffuse laterally and behave like static traps for the MβCD molecules. Cholesterol depletion causes morphology changes of domains but these disrupted monolayers domains seem to reform even when cholesterol level was low. PMID:27245215

  5. Tissue storage and control of cholesterol metabolism in man on high cholesterol diets.

    PubMed

    Quintão, E C; Brumer, S; Stechhahn, K

    1977-03-01

    The possibility of accumulation of tissue cholesterol in human beings submitted to high cholesterol feeding was investigated in liver biopsies and through fecal sterol balance studies. Feeding to 10 individuals 3.1 to 3.4 g/day of cholesterol for 3 weeks raised the mean serum level from 293 to 349 mg/100 ml, namely 19%, whereas the liver cholesterol content was 417 mg/100 g of wet weight. In 10 control cases eating 0.1--0.4 g/day of cholesterol serum cholesterol remained stable throughout the experimental period and the liver cholesterol content was 256 mg/100 g. Difference of liver colesterol level between the two groups was 62%. In 7 patients submitted to two periods of balance investigation on a cholesterol-free synthetic formula diet respectively prior to (PI) and after (PIII) eating the high cholesterol solid food from 4 to 15 weeks (PII), fecal steroid excretion in PIII exceeded PI in 3 patients. Such data are a direct evidence for the existence of an efficient system to release acutely stored cholesterol. In one patient bile acid excretion accounted for the difference between PIII and PI.

  6. Relative activity of cholesterol in OPPC/cholesterol/sphingomyelin mixtures measured with an acoustic sensor.

    PubMed

    Melzak, Kathryn A; Gizeli, Electra

    2009-03-01

    Acoustic devices are sensitive to the mole fraction of cholesterol present in liposomes adsorbed to the device surface as a result of the different mechanical properties of the liposomes. This fact was exploited to develop an acoustic assay to determine the relative affinity of cholesterol for different lipid mixtures. In the assay described here, the initial rate of beta-cyclodextrin-induced removal of cholesterol was measured for liposomes having a range of compositions. The initial rate of cholesterol removal was found to be directly proportional to the concentration of beta-cyclodextrin (betaCD) present over the range of 0-7.5 mg/ml (0-6.6 mM), consistent with other assays measuring the betaCD-accelerated transfer of cholesterol between liposomes. The affinity of cholesterol for 1-oleoyl-2-palmitoyl-sn-glycero-3-phosphocholine (OPPC) liposomes with a sphingomyelin mole fraction, chi(SPM), of 0.2 was found to be 1.4x higher than that for pure OPPC liposomes. For liposomes composed only of OPPC and cholesterol in varying ratios, the initial rate of cholesterol removal was determined as a function of cholesterol mole fraction (chi(C)). The initial rate of removal showed an increase at chi(C) = 0.13, consistent with phase diagrams showing the start of liquid ordered domain formation, but no such increase at chi(C) = 0.25, in contrast to the predictions of the umbrella model for OPPC/cholesterol interactions.

  7. Effect of dietary cholesterol and fat on cell cholesterol transfer to postprandial plasma in hyperlipidemic men.

    PubMed

    Sutherland, Wayne H F; de Jong, Sylvia A; Walker, Robert J

    2007-10-01

    Postprandial chylomicrons are potent ultimate acceptors of cell membrane cholesterol and are believed to accelerate reverse cholesterol transport (RCT). We compared the effects of meals rich in polyunsaturated fat (PUFA) and either high (605 mg) or low (151 mg) in cholesterol and a meal rich in dairy fat (DF) in the form of cream on net in vitro transport of red blood cell (RBC) membrane cholesterol to 4 and 6 h postprandial plasma in eight normotriglyceridemic (NTG-H) and eight hypertriglyceridemic (HTG-H) men with mild to moderate hypercholesterolemia. In HTG-H men, cell cholesterol accumulation in 6-h postprandial plasma was significantly (P = 0.02) less after the PUFA-HC meal compared with the other meals. The significant (P < 0.001) increase in cell plus endogenous cholesterol accumulation in the triglyceride-rich lipoprotein (TRL) fraction of 4 h postprandial plasma incubated with RBC was significantly (P = 0.007) higher after the PUFA-HC meal compared with DF meal in HTG-H men. In NTG-H men, cholesterol accumulation in plasma and plasma lipoproteins in the presence and absence of RBC was not significantly affected by the type of meal ingested. These data suggest that addition of large amounts of cholesterol to a PUFA meal may impair diffusion-mediated transport of cell membrane cholesterol to postprandial plasma and that replacing DF with PUFA in a meal increases postprandial lipemia and may potentially increase cholesterol accumulation in atherogenic postprandial TRL in HTG-H men.

  8. Cholesterol distribution in living cells: fluorescence imaging using dehydroergosterol as a fluorescent cholesterol analog.

    PubMed Central

    Mukherjee, S; Zha, X; Tabas, I; Maxfield, F R

    1998-01-01

    Cholesterol is an important constituent of most mammalian cell membranes and its concentration in various cellular membranes is tightly regulated. Although there is much information about cholesterol distribution and trafficking in cells, it is primarily derived from indirect measurements, and the results obtained using different approaches are often conflicting. A cholesterol analog that faithfully mimics the properties of cholesterol and can be followed in living cells would thus be very useful. In this study, we report the fluorescence imaging of such an analog, dehydroergosterol (DHE), in living cells. DHE differs from cholesterol in having three additional double bonds and an extra methyl group. In model systems, DHE closely mimics the behavior of native cholesterol. Using triple-labeling studies, we show that DHE colocalizes extensively with endocytosed transferrin, an endocytic recycling compartment marker, and with a marker for the trans-Golgi network, Tac-TGN38. This distribution of DHE is qualitatively similar to that observed when cells are labeled with the fluorescent cholesterol-binding polyene antibiotic, filipin, although there are differences in apparent proportions of DHE and filipin that are localized at the plasma membrane. Another cholesterol derivative, 25-NBD-cholesterol, has a structure that is compromised by the presence of a bulky NBD group and does not distribute to the same organelles as DHE or filipin. In addition, we show in this manuscript that kinetic processes can be followed in living cells by monitoring recovery of DHE fluorescence in a photobleached region over time. Our observations provide evidence for the presence of a large intracellular cholesterol pool in the endocytic recycling compartment and the trans-Golgi network that might play important roles in the trafficking of lipids, lipid-anchored proteins, and transmembrane proteins that preferentially partition into cholesterol-enriched membrane domains. In addition, this

  9. A church-based cholesterol education program.

    PubMed

    Wiist, W H; Flack, J M

    1990-01-01

    The leading cause of death among black people in the United States is coronary heart disease, accounting for about 25 percent of the deaths. The Task Force on Black and Minority Health formed by the Secretary of Health and Human Services in 1985 subsequently recommended increased efforts to reduce risk factors for coronary heart disease in the black population. A stated focus of the National Heart, Lung, and Blood Institute's National Cholesterol Education Program has been that of reaching minority groups. This report describes a pilot cholesterol education program conducted in black churches by trained members of those churches. Cholesterol screening, using a Reflotron, and other coronary heart disease risk factor screening was conducted in six churches with predominantly black members and at a neighborhood library. A total of 348 persons with cholesterol levels of 200 milligrams per deciliter (mg per dl) or higher were identified. At the time of screening, all were provided brief counseling on lowering their cholesterol and were given a copy of the screening results. Half of those identified, all members of one church, were invited to attend a 6-week nutrition education class of 1 hour each week about techniques to lower blood cholesterol. Information about cholesterol was also mailed to them. They were designated as the education group. Persons in the church were trained to teach the classes. A report of the screening results was sent to the personal physicians of the remaining 174 people in other churches who had cholesterol levels of 200 mg per dl or higher. This group served as a usual care comparison group.Six months after the initial screening, members of both groups were invited for followup screening.Among the 75 percent of the education group who returned for followup screening there was a 23.4 mg per dl (10 percent) decrease in the mean cholesterol level. Thirty-six percent of the usual care group returned for followup screening; their mean cholesterol

  10. Dietary Phospholipids and Intestinal Cholesterol Absorption

    PubMed Central

    Cohn, Jeffrey S.; Kamili, Alvin; Wat, Elaine; Chung, Rosanna W. S.; Tandy, Sally

    2010-01-01

    Experiments carried out with cultured cells and in experimental animals have consistently shown that phospholipids (PLs) can inhibit intestinal cholesterol absorption. Limited evidence from clinical studies suggests that dietary PL supplementation has a similar effect in man. A number of biological mechanisms have been proposed in order to explain how PL in the gut lumen is able to affect cholesterol uptake by the gut mucosa. Further research is however required to establish whether the ability of PLs to inhibit cholesterol absorption is of therapeutic benefit. PMID:22254012

  11. Acyl-coenzyme A:cholesterol acyltransferases

    PubMed Central

    Chang, Ta-Yuan; Li, Bo-Liang; Chang, Catherine C. Y.; Urano, Yasuomi

    2009-01-01

    The enzymes acyl-coenzyme A (CoA):cholesterol acyltransferases (ACATs) are membrane-bound proteins that utilize long-chain fatty acyl-CoA and cholesterol as substrates to form cholesteryl esters. In mammals, two isoenzymes, ACAT1 and ACAT2, encoded by two different genes, exist. ACATs play important roles in cellular cholesterol homeostasis in various tissues. This chapter summarizes the current knowledge on ACAT-related research in two areas: 1) ACAT genes and proteins and 2) ACAT enzymes as drug targets for atherosclerosis and for Alzheimer's disease. PMID:19141679

  12. Peripheral cholesterol, metabolic disorders and Alzheimer's disease.

    PubMed

    Ledesma, Maria Dolores; Dotti, Carlos Gerardo

    2012-01-01

    Strong correlations have been made between high levels of blood cholesterol and the risk to suffer Alzheimer's disease (AD). The question arises on how a peripheral event contributes to a disease that so severely affects the integrity and function of the Central Nervous System. Hypercholesterolemia has been also associated to peripheral metabolic disorders like diabetes, obesity or atherosclerosis that, in turn, predispose to AD. Here we review data, which point to alterations in blood cholesterol levels as a link between these metabolic disorders and AD. We describe and discuss common, cholesterol-related, molecular mechanisms and strategies to fight these conditions that, altogether, constitute a major cause of death in our societies.

  13. The role of cholesterol absorption and hepatic cholesterol content in high and low responses to dietary cholesterol and fat in pedigreed baboons (Papio species).

    PubMed

    Kushwaha, R S; Rice, K S; Lewis, D S; McGill, H C; Carey, K D

    1993-06-01

    Selective breeding has produced baboon families with low and high plasma cholesterol responses to dietary cholesterol and fat. We used 12 high- and 12 low-responding (mainly in low-density lipoprotein [LDL] cholesterol) pedigreed baboons to determine whether cholesterol absorption and hepatic cholesterol concentration are associated with these responses. We measured cholesterol absorption first on the chow diet, which was low in cholesterol and fat, and after 3 and 13 weeks on the challenge diets, which contained 0.45 mg cholesterol/kcal and 40% of calories as either coconut oil or corn oil. Plasma, lipoprotein, and hepatic cholesterol concentrations were measured 1 week after cholesterol absorption measurements. High-responding baboons had higher percentage cholesterol absorption than low-responding baboons on both chow and challenge diets, regardless of the type of dietary fat. Both high and low responders had higher percentage cholesterol absorption with corn oil than with coconut oil. High responders also had higher hepatic cholesterol concentrations than low responders on chow and after consuming the challenge diets for 4 weeks. After consuming the challenge diets for 14 weeks, low responders fed coconut oil had hepatic cholesterol levels equal to those of high responders, while low responders fed corn oil continued to have low hepatic cholesterol levels. Thus, percentage cholesterol absorption is consistently higher in high-responding baboons regardless of diet, but hepatic cholesterol concentration varies with duration of challenge and type of fat. The results suggest that both cholesterol absorption and hepatic cholesterol concentration regulate cholesterolemic responses to diet, but by different mechanisms.

  14. Wheat alkylresorcinols reduce micellar solubility of cholesterol in vitro and increase cholesterol excretion in mice.

    PubMed

    Horikawa, Kazumasa; Hashimoto, Chiaki; Kikuchi, Yosuke; Makita, Miki; Fukudome, Shin-Ichi; Okita, Kimiko; Wada, Naoyuki; Oishi, Katsutaka

    2017-03-01

    Epidemiological studies have shown that the consumption of whole grains can reduce risk for metabolic disorders. We recently showed that chronic supplementation with wheat alkylresorcinols (ARs) prevents glucose intolerance and insulin resistance with hepatic lipid accumulation induced in mice by a high-fat high-sucrose diet (HFHSD). This study examines the effects of ARs on the micellar solubility of cholesterol in vitro, as well as the effects of transient AR supplementation on faecal lipid excretion and plasma lipid levels in mice. We found that ARs formed bile micelles with taurocholate independently of phospholipids, and dose-dependently decreased the micellar solubility of cholesterol in a biliary micelle model. Transient AR supplementation with HFHSD increased faecal cholesterol and triglyceride contents and decreased plasma cholesterol concentrations. These suggest that one underlying mechanism through which ARs suppress diet-induced obesity is by interfering with the micellar cholesterol solubilisation in the digestive tract, which subsequently decreases cholesterol absorption.

  15. How Is High Blood Cholesterol Treated?

    MedlinePlus

    ... fat is found in some meats, dairy products, chocolate, baked goods, and deep-fried and processed foods. ... and raise your HDL cholesterol level. People gain health benefits from as little as 60 minutes of moderate- ...

  16. [Relation between cholesterol levels and neuropsychiatric disorders].

    PubMed

    Martínez-Carpio, P A; Barba, J; Bedoya-Del Campillo, A

    A recent survey raised doubts about most of the associations between hypocholesterolemia and neuropsychiatric diseases. Nevertheless, there is scientific evidence (some very recent) that demonstrates a link between possible brain disorders and reduced levels of cholesterol. To conduct a systematic study of the literature that addresses the relation between low cholesterol levels in serum and neuropsychiatric disorders. Relevant papers were identified by means of a systematic search and selection of the literature on Medline (August 2008). The selected papers were reviewed using statistical analysis and critical-deductive reasoning. It is shown that low cholesterol levels in serum are associated and related to different neuropsychiatric disorders. Lowered cholesterol levels seem likely to be linked to higher rates of early death, suicide, aggressive and violent behaviour, personality disorders, and possibly depression, dementia and penal confinement among young males. Further studies are needed to confirm the evidence currently available and to relate more accurate diagnoses with hypocholesterolemia.

  17. Cholesterol emboli Livedo Reticularis - feet (image)

    MedlinePlus

    Cholesterol emboli block small vessels in dependent areas of the body, here on the foot. The resulting superficial tissue may infarct, and lower vessels may dilate to try and compensate. This creates a livedo, or 'lace-like' pattern.

  18. HDL Function, Dysfunction, and Reverse Cholesterol Transport

    PubMed Central

    Fisher, Edward A.; Feig, Jonathan E.; Hewing, Bernd; Hazen, Stanley L.; Smith, Jonathan D.

    2012-01-01

    Although high HDL-cholesterol levels are associated with decreased cardiovascular risk in epidemiological studies, recent genetic and pharmacological findings have raised doubts about the beneficial effects of HDL. Raising HDL levels in animal models by infusion or over expression of apolipoprotein A-I has shown clear vascular improvements, such as delayed atherosclerotic lesion progression and accelerated lesion regression, along with increased reverse cholesterol transport. Inflammation and other factors, such as myeloperoxidase mediated oxidation, can impair HDL production and HDL function, in regard to its reverse cholesterol transport, antioxidant, and anti-inflammatory activities. Thus, tests of HDL function, which have not yet been developed as routine diagnostic assays, may prove useful and be a better predictor of cardiovascular risk than HDL-cholesterol levels. PMID:23152494

  19. [Cholesterol and atherosclerosis. Historical considerations and treatment].

    PubMed

    Zárate, Arturo; Manuel-Apolinar, Leticia; Basurto, Lourdes; De la Chesnaye, Elsa; Saldívar, Iván

    2016-01-01

    Cholesterol is a precursor of steroid hormones and an essential component of the cell membrane, however, altered regulation of the synthesis, absorption and excretion of cholesterol predispose to cardiovascular diseases of atherosclerotic origin. Despite, the recognition of historical events for 200 years, starting with Michel Chevreul naming «cholesterol»; later on, Lobstein coining the term atherosclerosis and Marchand introducing it, Anichkov identifying cholesterol in atheromatous plaque, and Brown and Goldstein discovering LDL receptor; as well as the emerging of different drugs, such as fibrates, statins and cetrapibs this decade, promising to increase HDL and the most recent ezetimibe and anti-PCSK9 to inhibit the degradation of LDL receptor, however morbidity has not been reduced in cardiovascular disease. Copyright © 2016. Published by Masson Doyma México S.A.

  20. HDL (Good), LDL (Bad) Cholesterol and Triglycerides

    MedlinePlus

    ... and proteins. These are called – no big surprise – lipoproteins. Two types of lipoproteins carry cholesterol to and from cells. One is low-density lipoprotein, or LDL. The other is high-density lipoprotein, ...

  1. SNAREs and cholesterol movement for steroidogenesis.

    PubMed

    Kraemer, Fredric B; Shen, Wen-Jun; Azhar, Salman

    2017-02-05

    Steroidogenesis is a complex process through which cholesterol traffics to mitochondria and is converted via a series of enzymatic steps to steroid hormones. Although the rate-limiting step in this process is the movement of cholesterol from the outer to the inner mitochondrial membrane via the actions of StAR, a continuous supply of cholesterol must be delivered to the outer mitochondrial membrane during active steroidogenesis and this is derived from multiple sources, including lipoprotein uptake, endogenous cholesterol synthesis and release from stores within cytoplasmic lipid droplets. A number of mechanisms have been suggested to contribute to cholesterol trafficking to mitochondria; however, there is no definitive consensus and this is particularly so in regards to trafficking from cytoplasmic lipid droplets. In this paper we review experiments in which we have surveyed the expression of SNARE proteins in steroidogenic tissue and cells and examined the role of SNAREs in mediating cholesterol movement from lipid droplets to the mitochondria based on multiple studies that identified SNAREs as components of cytoplasmic lipid droplets. We established and characterized an in vitro mitochondria reconstitution assay system that enabled us to examine the impact of adding recombinant SNARE proteins specifically on the movement of cholesterol from model lipid droplets to the outer mitochondrial membrane. Using this reconstitution assay system in combination with siRNA knockdown experiments in rat primary granulosa cells or in steroidogenic cell lines, we showed that several SNARE proteins are important components in the trafficking of cholesterol from lipid droplets to the mitochondria for steroidogenesis.

  2. Fat-induced membrane cholesterol accrual provokes cortical filamentous actin destabilisation and glucose transport dysfunction in skeletal muscle.

    PubMed

    Habegger, K M; Penque, B A; Sealls, W; Tackett, L; Bell, L N; Blue, E K; Gallagher, P J; Sturek, M; Alloosh, M A; Steinberg, H O; Considine, R V; Elmendorf, J S

    2012-02-01

    Diminished cortical filamentous actin (F-actin) has been implicated in skeletal muscle insulin resistance, yet the mechanism(s) is unknown. Here we tested the hypothesis that changes in membrane cholesterol could be a causative factor, as organised F-actin structure emanates from cholesterol-enriched raft microdomains at the plasma membrane. Skeletal muscle samples from high-fat-fed animals and insulin-sensitive and insulin-resistant human participants were evaluated. The study also used L6 myotubes to directly determine the impact of fatty acids (FAs) on membrane/cytoskeletal variables and insulin action. High-fat-fed insulin-resistant animals displayed elevated levels of membrane cholesterol and reduced F-actin structure compared with normal chow-fed animals. Moreover, human muscle biopsies revealed an inverse correlation between membrane cholesterol and whole-body glucose disposal. Palmitate-induced insulin-resistant myotubes displayed membrane cholesterol accrual and F-actin loss. Cholesterol lowering protected against the palmitate-induced defects, whereas characteristically measured defects in insulin signalling were not corrected. Conversely, cholesterol loading of L6 myotube membranes provoked a palmitate-like cytoskeletal/GLUT4 derangement. Mechanistically, we observed a palmitate-induced increase in O-linked glycosylation, an end-product of the hexosamine biosynthesis pathway (HBP). Consistent with HBP activity affecting the transcription of various genes, we observed an increase in Hmgcr, a gene that encodes 3-hydroxy-3-methyl-glutaryl coenzyme A reductase, the rate-limiting enzyme in cholesterol synthesis. In line with increased HBP activity transcriptionally provoking a membrane cholesterol-based insulin-resistant state, HBP inhibition attenuated Hmgcr expression and prevented membrane cholesterol accrual, F-actin loss and GLUT4/glucose transport dysfunction. Our results suggest a novel cholesterolgenic-based mechanism of FA-induced membrane

  3. Role of cholesterol in parasitic infections

    PubMed Central

    Bansal, Devendra; Bhatti, Harinderpal Singh; Sehgal, Rakesh

    2005-01-01

    The requirement of cholesterol for internalization of eukaryotic pathogens like protozoa (Leishmaniasis, Malaria and Toxoplasmosis) and the exchange of cholesterol along with other metabolites during reproduction in Schistosomes (helminths) under variable circumstances are poorly understood. In patients infected with some other helminthes, alterations in the lipid profile have been observed. Also, the mechanisms involved in lipid changes especially in membrane proteins related to parasite infections remain uncertain. Present review of literature shows that parasites induce significant changes in lipid parameters, as has been shown in the in vitro study where substitution of serum by lipid/cholesterol in medium and in experimental models (in vivo). Thus changes in lipid profile occur in patients having active infections with most of the parasites. Membrane proteins are probably involved in such reactions. All parasites may be metabolising cholesterol, but the exact relationship with pathogenic mechanism is not clear. So far, studies suggest that there may be some factors or enzymes, which allow the parasite to breakup and consume lipid/cholesterol. Further studies are needed for better understanding of the mechanisms involved in vivo. The present review analysis the various studies till date and the role of cholesterol in pathogenesis of different parasitic infections. PMID:15882457

  4. Development of cholesterol biosensor based on immobilized cholesterol esterase and cholesterol oxidase on oxygen electrode for the determination of total cholesterol in food samples.

    PubMed

    Basu, Anjan Kumar; Chattopadhyay, Parimal; Roychoudhuri, Utpal; Chakraborty, Runu

    2007-05-01

    The development of a cholesterol biosensor by co-immobilization of cholesterol esterase (ChEt) and cholesterol oxidase (ChOX) on oxygen electrode is described. The electrode consists of gold cathode and Ag/AgCl anode. The enzymes were immobilized by cross-linking with glutaraldehyde and Bovine Serum Albumin (BSA). The immobilized enzymatic membrane was attached to the tip of the electrode by a push cap system. The optimum pH and temperature of the sensor was determined, these are 6 and 25 degrees C respectively. The developed sensor was calibrated from 1-75 mg/dl of cholesterol palmiate and found linear in the range of 2-50 mg/dL. The calibration curve was drawn with V(i) (ppm/min)(initial velocity) vs different concentrations of cholesterol palmiate (mg/dL). The application of the sensor to determine the total cholesterol in different real food samples such as egg, meat was investigated. The immobilized enzymatic layer can be reused over 30 times and the stability of the enzymatic layer was studied up to 9 weeks.

  5. Obesity, cholesterol metabolism, and breast cancer pathogenesis.

    PubMed

    McDonnell, Donald P; Park, Sunghee; Goulet, Matthew T; Jasper, Jeff; Wardell, Suzanne E; Chang, Ching-Yi; Norris, John D; Guyton, John R; Nelson, Erik R

    2014-09-15

    Obesity and altered lipid metabolism are risk factors for breast cancer in pre- and post-menopausal women. These pathologic relationships have been attributed in part to the impact of cholesterol on the biophysical properties of cell membranes and to the influence of these changes on signaling events initiated at the membrane. However, more recent studies have indicated that the oxysterol 27-hydroxycholesterol (27HC), and not cholesterol per se, may be the primary biochemical link between lipid metabolism and cancer. The enzyme responsible for production of 27HC from cholesterol, CYP27A1, is expressed primarily in the liver and in macrophages. In addition, significantly elevated expression of this enzyme within breast tumors has also been observed. It is believed that 27HC, acting through the liver X receptor in macrophages and possibly other cells, is involved in maintaining organismal cholesterol homeostasis. It has also been shown recently that 27HC is an estrogen receptor agonist in breast cancer cells and that it stimulates the growth and metastasis of tumors in several models of breast cancer. These findings provide the rationale for the clinical evaluation of pharmaceutical approaches that interfere with cholesterol/27HC synthesis as a means to mitigate the impact of cholesterol on breast cancer pathogenesis. Cancer Res; 74(18); 4976-82. ©2014 AACR. ©2014 American Association for Cancer Research.

  6. Obesity, Cholesterol Metabolism and Breast Cancer Pathogenesis

    PubMed Central

    McDonnell, Donald P.; Park, Sunghee; Goulet, Matthew T.; Jasper, Jeff; Wardell, Suzanne E.; Chang, Ching-yi; Norris, John D.; Guyton, John R.; Nelson, Erik R.

    2014-01-01

    Obesity and altered lipid metabolism are risk factors for breast cancer in pre- and post-menopausal women. These pathologic relationships have been attributed in part to the impact of cholesterol on the biophysical properties of cell membranes and to the influence of these changes on signaling events initiated at the membrane. However, more recent studies have indicated that the oxysterol 27-hydroxycholesterol (27HC), and not cholesterol per se, may be the primary biochemical link between lipid metabolism and cancer. The enzyme responsible for production of 27HC from cholesterol, CYP27A1, is expressed primarily in the liver and in macrophages. In addition significantly elevated expression of this enzyme within breast tumors has also been observed. It is believed that 27HC, acting through the liver X receptor (LXR) in macrophages and possibly other cells is involved in maintaining organismal cholesterol homeostasis. It has also been shown recently that 27HC is an estrogen receptor (ER) agonist in breast cancer cells and that it stimulates the growth and metastasis of tumors in several models of breast cancer. These findings provide the rationale for the clinical evaluation of pharmaceutical approaches that interfere with cholesterol/27HC synthesis as a means to mitigate the impact of cholesterol on breast cancer pathogenesis. PMID:25060521

  7. Human paraoxonase 1 overexpression in mice stimulates HDL cholesterol efflux and reverse cholesterol transport

    PubMed Central

    Ikhlef, Souade; Berrougui, Hicham; Kamtchueng Simo, Olivier; Zerif, Echarki

    2017-01-01

    This study was aimed to investigate the effect of human PON1 overexpression in mice on cholesterol efflux and reverse cholesterol transport. PON1 overexpression in PON1-Tg mice induced a significant 3-fold (p<0.0001) increase in plasma paraoxonase activity and a significant ~30% (p<0.0001) increase in the capacity of HDL to mediate cholesterol efflux from J774 macrophages compared to wild-type mice. It also caused a significant 4-fold increase (p<0.0001) in the capacity of macrophages to transfer cholesterol to apoA-1, a significant 2-fold (p<0.0003) increase in ABCA1 mRNA and protein expression, and a significant increase in the expression of PPARγ (p<0.0003 and p<0.04, respectively) and LXRα (p<0.0001 and p<0.01, respectively) mRNA and protein compared to macrophages from wild-type mice. Moreover, transfection of J774 macrophages with human PON1 also increased ABCA1, PPARγ and LXRα protein expression and stimulates macrophages cholesterol efflux to apo A1. In vivo measurements showed that the overexpression of PON1 significantly increases the fecal elimination of macrophage-derived cholesterol in PON1-Tg mice. Overall, our results suggested that the overexpression of PON1 in mice may contribute to the regulation of the cholesterol homeostasis by improving the capacity of HDL to mediate cholesterol efflux and by stimulating reverse cholesterol transport. PMID:28278274

  8. Cholesterol modulates the dimer interface of the β₂-adrenergic receptor via cholesterol occupancy sites.

    PubMed

    Prasanna, Xavier; Chattopadhyay, Amitabha; Sengupta, Durba

    2014-03-18

    The β2-adrenergic receptor is an important member of the G-protein-coupled receptor (GPCR) superfamily, whose stability and function are modulated by membrane cholesterol. The recent high-resolution crystal structure of the β2-adrenergic receptor revealed the presence of possible cholesterol-binding sites in the receptor. However, the functional relevance of cholesterol binding to the receptor remains unexplored. We used MARTINI coarse-grained molecular-dynamics simulations to explore dimerization of the β2-adrenergic receptor in lipid bilayers containing cholesterol. A novel (to our knowledge) aspect of our results is that receptor dimerization is modulated by membrane cholesterol. We show that cholesterol binds to transmembrane helix IV, and cholesterol occupancy at this site restricts its involvement at the dimer interface. With increasing cholesterol concentration, an increased presence of transmembrane helices I and II, but a reduced presence of transmembrane helix IV, is observed at the dimer interface. To our knowledge, this study is one of the first to explore the correlation between cholesterol occupancy and GPCR organization. Our results indicate that dimer plasticity is relevant not just as an organizational principle but also as a subtle regulatory principle for GPCR function. We believe these results constitute an important step toward designing better drugs for GPCR dimer targets.

  9. Three pools of plasma membrane cholesterol and their relation to cholesterol homeostasis

    PubMed Central

    Das, Akash; Brown, Michael S; Anderson, Donald D; Goldstein, Joseph L; Radhakrishnan, Arun

    2014-01-01

    When human fibroblasts take up plasma low density lipoprotein (LDL), its cholesterol is liberated in lysosomes and eventually reaches the endoplasmic reticulum (ER) where it inhibits cholesterol synthesis by blocking activation of SREBPs. This feedback protects against cholesterol overaccumulation in the plasma membrane (PM). But how does ER know whether PM is saturated with cholesterol? In this study, we define three pools of PM cholesterol: (1) a pool accessible to bind 125I-PFO*, a mutant form of bacterial Perfringolysin O, which binds cholesterol in membranes; (2) a sphingomyelin(SM)-sequestered pool that binds 125I-PFO* only after SM is destroyed by sphingomyelinase; and (3) a residual pool that does not bind 125I-PFO* even after sphingomyelinase treatment. When LDL-derived cholesterol leaves lysosomes, it expands PM's PFO-accessible pool and, after a short lag, it also increases the ER's PFO-accessible regulatory pool. This regulatory mechanism allows cells to ensure optimal cholesterol levels in PM while avoiding cholesterol overaccumulation. DOI: http://dx.doi.org/10.7554/eLife.02882.001 PMID:24920391

  10. Cyclodextrin (CD) complexes of cholesterol--their potential use in reducing dietary cholesterol intake.

    PubMed

    Somogyi, G; Posta, J; Buris, L; Varga, M

    2006-02-01

    The main objective of this investigation was to test and see if cyclodextrins, a type of molecule which form inclusion complexes, could effectively prevent the absorption of food derived cholesterol. Cyclodextrins are nontoxic and easily tolerated, having only a slight sweet taste. alpha,beta,gamma-Cyclodextrins, 2-Hydroxypropyl-beta-cyclodextrin (2-HPCD), and heptakis-O,O-dimethyl-beta-cyclodextrin (DMCD) were tested in solutions of different concentrations. These solutions were then saturated with cholesterol and the excess cholesterol was removed. The clear solutions left were then analyzed by HPLC to assess the amount of cholesterol in the solutions, and compared to a standard. DMCD gave the best results in successfully dissolving (complexing) most of the cholesterol followed by HPCD and alpha-cyclodextrin. Beta- and gamma-CD showed nearly insignificant complex formation. After administration of 10 mg of cholesterol to mice through a gastric tube, the cholesterol level increased about 125-130%, and only 15-20%, if the cholesterol was administered together with 20 mg of DMCD. That means, the DMCD formed complexes with approximately 80-85% of the cholesterol administered in the mice gastrointestinal tract.

  11. Dietary Cholesterol Impairs Memory and Memory Increases Brain Cholesterol and Sulfatide Levels

    PubMed Central

    Darwish, Deya S.; Wang, Desheng; Konat, Gregory W.; Schreurs, Bernard G.

    2011-01-01

    Cholesterol and sulfatides play many important roles in learning and memory. To date, our observations about the effects of cholesterol on learning have been assessed during response acquisition i.e., the learning of a new memory. Here we report for the first time on the effect of a cholesterol diet on a previously formed memory. Rabbits were given trace conditioning of the nictitating membrane response for ten days, then fed a 2% cholesterol diet for eight weeks, and then assessed for memory recall of the initially learned task. We show that dietary cholesterol had an adverse effect on memory recall. Second, we investigated whether dietary cholesterol caused an increase in brain cholesterol and sulfatide levels in four major brain structures (hippocampus, frontal lobe, brainstem, and cerebellum) using a technique for analyzing myelin and myelin-free fractions separately. Although our data confirm previous findings that dietary cholesterol does not directly affect cholesterol and establish that it does not affect sulfatide levels in the brain, these levels did increase rather significantly in the hippocampus and frontal lobe as a function of learning and memory. PMID:20141286

  12. Human carotid atherosclerotic lesion protein components decrease cholesterol biosynthesis rate in macrophages through 3-hydroxy-3-methylglutaryl-CoA reductase regulation.

    PubMed

    Cohen, Elad; Aviram, Michael; Khatib, Soliman; Rosenblat, Mira; Vaya, Jacob

    2015-01-01

    Atherosclerosis is characterized by the formation of cholesterol-loaded macrophages, which are turned into foam cells, the hallmark of early atherogenesis. As part of ongoing research on the interactions among human carotid lesion components and blood elements, the effect of plaque homogenate on macrophage cholesterol biosynthesis rate was examined. Human carotid plaques were ground, extracted with phosphate-buffered saline (homogenate), and then added to the macrophage medium. This extract decreased macrophage cholesterol biosynthesis rate up to 50% in a dose-dependent manner. Cholesterol or lipoproteins were separated from the homogenate and added to the MQ medium. Unlike the homogenate, neither free cholesterol nor the lipoproteins were able to inhibit cholesterol biosynthesis rate under the above experimental concentration, suggesting that the homogenate-induced cholesterol biosynthesis inhibition in our experimental system was not owing to the feedback inhibition of cholesterol. Furthermore, the homogenate remaining after lipoprotein removal (lipoprotein-deficient homogenate) also decreased cholesterol biosynthesis rate, whereas boiled homogenate or phospholipids extracted from the homogenate decreased macrophage cholesterol biosynthesis rate only partially. Finally, cholesterol biosynthesis inhibition was achieved only upon using the precursor [(3)H]acetate, but not [(14)C]mevalonate, suggesting that 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCoA Reductase), the rate-limiting enzyme in the cholesterol biosynthesis pathway, is involved in the above antiatherogenic effect of the homogenate, whereas the treatment with homogenate decreased HMGCoA Reductase mRNA. Proteins and phospholipids from human carotid lesion homogenate decrease cholesterol biosynthesis rate in macrophages secondary to HMGCoA Reductase feedback regulation. Such an effect may delay foam cell formation and atherosclerosis progression.

  13. Sustained release Curcumin loaded Solid Lipid Nanoparticles

    PubMed Central

    Jourghanian, Parisa; Ghaffari, Solmaz; Ardjmand, Mehdi; Haghighat, Setareh; Mohammadnejad, Mahdieh

    2016-01-01

    Purpose: curcumin is poorly water soluble drug with low bioavailability. Use of lipid systems in lipophilic substances increases solubility and bioavailability of poorly soluble drugs. The aim of this study was to prepare curcumin loaded Solid Lipid Nanoparticles (SLNs) with high loading efficiency, small particle size and prolonged release profile with enhanced antibacterial efficacy. Methods: to synthesize stable SLNs, freeze- Drying was done using mannitol as cryoprotectant. Cholesterol was used as carrier because of good tolerability and biocompatibility. SLNs were prepared using high pressure homogenization method. Results: optimized SLNs had 112 and 163 nm particle size before and after freeze drying, respectively. The prepared SLNs had 71% loading efficiency. 90% of loaded curcumin was released after 48 hours. Morphologic study for formulation was done by taking SEM pictures of curcumin SLNs. Results show the spherical shape of curcumin SLNs. DSC studies were performed to determine prolonged release mechanism. Antimicrobial studies were done to compare the antimicrobial efficacy of curcumin SLNs with free curcumin. DSC studies showed probability of formation of hydrogen bonds between cholesterol and curcumin which resulted in prolonged release of curcumin. Lipid structure of cholesterol could cause enhanced permeability in studied bacteria to increase antibacterial characteristics of curcumin. Conclusion: the designed curcumin SLNs could be candidate for formulation of different dosage forms or cosmeceutical products. PMID:27123413

  14. miR-758 regulates cholesterol efflux through post-transcriptional repression of ABCA1

    PubMed Central

    Ramirez, Cristina M.; Dávalos, Alberto; Goedeke, Leigh; Salerno, Alessandro G.; Warrier, Nikhil; Cirera-Salinas, Daniel; Suárez, Yajaira; Fernández-Hernando, Carlos

    2012-01-01

    Objective The ATP-binding cassette transporter A1 (ABCA1) is a major regulator of macrophage cholesterol efflux and protects cells from excess intracellular cholesterol accumulation, however the mechanism involved in posttranscriptional regulation of ABCA1 is poorly understood. We previously showed miR-33 was one regulator. Here we investigated the potential contribution of other microRNAs (miRNAs) to post-transcriptionally regulate ABCA1 and macrophage cholesterol efflux. Methods and Results We performed a bioinformatic analaysis for identifying miRNA target prediction sites in ABCA1 gene and an unbiased genome-wide screen to identify miRNAs modulated by cholesterol excess in mouse peritoneal macrophages. Quantitative real-time RT-PCR confirmed that miR-758 is repressed in cholesterol-loaded macrophages. Under physiological conditions, high dietary fat excess in mice repressed mir-758 both in peritoneal macrophages and, to a lesser extent in the liver. In mouse and human cells in vitro, miR-758 repressed the expression of ABCA1 and conversely the inhibition of this miRNA by using anti-miR-758 increased ABCA1 expression. In mouse cells, mir-758 reduced cellular cholesterol efflux to apoA1 and anti-miR-758 increased it. miR-758 directly targets the 3′UTR of Abca1 as assessed by 3′UTR luciferase reporter assays. Interestingly, miR-758 is highly expressed in the brain where also target several genes involved in neurological functions including SLC38A1, NTM, EPHA7 and MYT1L. Conclusion We identified miR-758 as a novel miRNA that post-transcriptionally controls ABCA1 levels in different cells and regulates macrophage cellular cholesterol efflux to apoA1, opening new avenues to increase apoA1 and raise HDL levels. PMID:21885853

  15. Cholesterol-Independent Effects of Methyl-β-Cyclodextrin on Chemical Synapses

    PubMed Central

    Ormerod, Kiel G.; Coorssen, Jens R.; Mercier, A. Joffre

    2012-01-01

    The cholesterol chelating agent, methyl-β-cyclodextrin (MβCD), alters synaptic function in many systems. At crayfish neuromuscular junctions, MβCD is reported to reduce excitatory junctional potentials (EJPs) by impairing impulse propagation to synaptic terminals, and to have no postsynaptic effects. We examined the degree to which physiological effects of MβCD correlate with its ability to reduce cholesterol, and used thermal acclimatization as an alternative method to modify cholesterol levels. MβCD impaired impulse propagation and decreased EJP amplitude by 40% (P<0.05) in preparations from crayfish acclimatized to 14°C but not from those acclimatized to 21°C. The reduction in EJP amplitude in the cold-acclimatized group was associated with a 49% reduction in quantal content (P<0.05). MβCD had no effect on input resistance in muscle fibers but decreased sensitivity to the neurotransmitter L-glutamate in both warm- and cold-acclimatized groups. This effect was less pronounced and reversible in the warm-acclimatized group (90% reduction in cold, P<0.05; 50% reduction in warm, P<0.05). MβCD reduced cholesterol in isolated nerve and muscle from cold- and warm-acclimatized groups by comparable amounts (nerve: 29% cold, 25% warm; muscle: 20% cold, 18% warm; P<0.05). This effect was reversed by cholesterol loading, but only in the warm-acclimatized group. Thus, effects of MβCD on glutamate-sensitivity correlated with its ability to reduce cholesterol, but effects on impulse propagation and resulting EJP amplitude did not. Our results indicate that MβCD can affect both presynaptic and postsynaptic properties, and that some effects of MβCD are unrelated to cholesterol chelation. PMID:22590538

  16. Thermotropic lipid phase separations in human erythrocyte ghosts and cholesterol-enriched rat liver plasma membranes.

    PubMed

    Gordon, L M; Mobley, P W

    1984-01-01

    Electron spin resonance (ESR) studies of human erythrocyte ghosts labeled with 5-nitroxide stearate, I(12,3), indicate that a temperature-dependent lipid phase separation occurs with a high onset at 38 degrees C. Cooling below 38 degrees C induces I(12,3) clustering. Similar phase separations were previously identified in human platelet and cholesterol-loaded [cholesterol/phospholipid molar ratio (C/P) = 0.85] rat liver plasma membranes [L.M. Gordon et al., 1983; J. Membrane Biol. 76; 139-149]; these were attributed to redistribution of endogenous lipid components such that I(12,3) is excluded from cholesterol-rich domains and tends to reside in cholesterol-poor domains. Further enrichment of rat liver plasma membranes to C/P ratios of 0.94-0.98 creates an "artificial" system equivalent to human erythrocyte ghosts (C/P = 0.90), using such criteria as probe flexibility, temperature dependent I(12,3) clustering; and polarity of the probe environment. Consequently, cholesterol-rich and -poor domains probably exist in both erythrocyte ghosts and high cholesterol liver membranes at physiologic temperatures. The temperature dependence of cold-induced hypertonic lysis of intact human erythrocytes was examined by incubating cells in 0.9 M sucrose for 10 min at 1 degree C intervals between 9 and 46 degrees C (Stage 1), and then subjecting them to 0 degrees C for 10 min (Stage 2). Plots of released hemoglobin are approx. sigmoidal, with no lysis below 18 degrees C and maximal lysis above 40 degrees C. The protective effect of low temperatures during Stage 1 may be due to the formation of cholesterol-rich domains that alter the bilayer distribution and/or conformation of critical membrane-associated proteins.

  17. Enhanced vascular permeability facilitates entry of plasma HDL and promotes macrophage-reverse cholesterol transport from skin in mice

    PubMed Central

    Kareinen, Ilona; Cedó, Lídia; Silvennoinen, Reija; Laurila, Pirkka-Pekka; Jauhiainen, Matti; Julve, Josep; Blanco-Vaca, Francisco; Escola-Gil, Joan Carles; Kovanen, Petri T.; Lee-Rueckert, Miriam

    2015-01-01

    Reverse cholesterol transport (RCT) pathway from macrophage foam cells initiates when HDL particles cross the endothelium, enter the interstitial fluid, and induce cholesterol efflux from these cells. We injected [3H]cholesterol-loaded J774 macrophages into the dorsal skin of mice and measured the transfer of macrophage-derived [3H]cholesterol to feces [macrophage-RCT (m-RCT)]. Injection of histamine to the macrophage injection site increased locally vascular permeability, enhanced influx of intravenously administered HDL, and stimulated m-RCT from the histamine-treated site. The stimulatory effect of histamine on m-RCT was abolished by prior administration of histamine H1 receptor (H1R) antagonist pyrilamine, indicating that the histamine effect was H1R-dependent. Subcutaneous administration of two other vasoactive mediators, serotonin or bradykinin, and activation of skin mast cells to secrete histamine and other vasoactive compounds also stimulated m-RCT. None of the studied vasoactive mediators affected serum HDL levels or the cholesterol-releasing ability of J774 macrophages in culture, indicating that acceleration of m-RCT was solely due to increased availability of cholesterol acceptors in skin. We conclude that disruption of the endothelial barrier by vasoactive compounds enhances the passage of HDL into interstitial fluid and increases the rate of RCT from peripheral macrophage foam cells, which reveals a novel tissue cholesterol-regulating function of these compounds. PMID:25473102

  18. Enhanced vascular permeability facilitates entry of plasma HDL and promotes macrophage-reverse cholesterol transport from skin in mice.

    PubMed

    Kareinen, Ilona; Cedó, Lídia; Silvennoinen, Reija; Laurila, Pirkka-Pekka; Jauhiainen, Matti; Julve, Josep; Blanco-Vaca, Francisco; Escola-Gil, Joan Carles; Kovanen, Petri T; Lee-Rueckert, Miriam

    2015-02-01

    Reverse cholesterol transport (RCT) pathway from macrophage foam cells initiates when HDL particles cross the endothelium, enter the interstitial fluid, and induce cholesterol efflux from these cells. We injected [(3)H]cholesterol-loaded J774 macrophages into the dorsal skin of mice and measured the transfer of macrophage-derived [(3)H]cholesterol to feces [macrophage-RCT (m-RCT)]. Injection of histamine to the macrophage injection site increased locally vascular permeability, enhanced influx of intravenously administered HDL, and stimulated m-RCT from the histamine-treated site. The stimulatory effect of histamine on m-RCT was abolished by prior administration of histamine H1 receptor (H1R) antagonist pyrilamine, indicating that the histamine effect was H1R-dependent. Subcutaneous administration of two other vasoactive mediators, serotonin or bradykinin, and activation of skin mast cells to secrete histamine and other vasoactive compounds also stimulated m-RCT. None of the studied vasoactive mediators affected serum HDL levels or the cholesterol-releasing ability of J774 macrophages in culture, indicating that acceleration of m-RCT was solely due to increased availability of cholesterol acceptors in skin. We conclude that disruption of the endothelial barrier by vasoactive compounds enhances the passage of HDL into interstitial fluid and increases the rate of RCT from peripheral macrophage foam cells, which reveals a novel tissue cholesterol-regulating function of these compounds.

  19. The Impairment of Macrophage-to-Feces Reverse Cholesterol Transport during Inflammation Does Not Depend on Serum Amyloid A

    PubMed Central

    de Beer, Maria C.; Wroblewski, Joanne M.; Noffsinger, Victoria P.; Meyer, Jason M.; van der Westhuyzen, Deneys R.

    2013-01-01

    Studies suggest that inflammation impairs reverse cholesterol transport (RCT). We investigated whether serum amyloid A (SAA) contributes to this impairment using an established macrophage-to-feces RCT model. Wild-type (WT) mice and mice deficient in SAA1.1 and SAA2.1 (SAAKO) were injected intraperitoneally with 3H-cholesterol-labeled J774 macrophages 4 hr after administration of LPS or buffered saline. 3H-cholesterol in plasma 4 hr after macrophage injection was significantly reduced in both WT and SAAKO mice injected with LPS, but this was not associated with a reduced capacity of serum from LPS-injected mice to promote macrophage cholesterol efflux in vitro. Hepatic accumulation of 3H-cholesterol was unaltered in either WT or SAAKO mice by LPS treatment. Radioactivity present in bile and feces of LPS-injected WT mice 24 hr after macrophage injection was reduced by 36% (P < 0.05) and 80% (P < 0.001), respectively. In contrast, in SAAKO mice, LPS did not significantly reduce macrophage-derived 3H-cholesterol in bile, and fecal excretion was reduced by only 45% (P < 0.05). Injection of cholesterol-loaded allogeneic J774 cells, but not syngeneic bone-marrow-derived macrophages, transiently induced SAA in C57BL/6 mice. Our study confirms reports that acute inflammation impairs steps in the RCT pathway and establishes that SAA plays only a minor role in this impairment. PMID:23431457

  20. Signal transduction pathways provide opportunities to enhance HDL and apoAI-dependent reverse cholesterol transport.

    PubMed

    Mulay, Vishwaroop; Wood, Peta; Rentero, Carles; Enrich, Carlos; Grewal, Thomas

    2012-02-01

    Binding of High Density Lipoprotein (HDL) and its major apolipoprotein A-I (apoA-I) to cell surface receptors is believed to initiate a plethora of signaling cascades that promote atheroprotective cell behavior, including the removal of excess cholesterol from lipid-loaded macrophages. More specifically, HDL and apoA-I binding to scavenger receptor BI (SR-BI) and ATP-binding cassette (ABC) transporter A1 has been shown to activate protein kinase A and C (PKA, PKC), Rac/Rho GTPases, Janus Kinase 2 (JAK2), calmodulin as well as mitogen-activated protein kinases (MAPK). Some of these signaling events upregulate mobilization of cholesterol from cellular pools, while others promote efflux pathways through increased expression, stability, and cell surface localization of SR-BI and ABCA1. This review aims to summarize the current knowledge of HDL- and apoA-I -induced signal transduction pathways that are linked to cholesterol efflux and discusses the underlying mechanisms that could couple ligand binding to SR-BI and ABCA1 with signaling and cholesterol export. Additional focus is given on the potential of pharmacological intervention to modulate the activity of signaling cascades for the inhibition or regression of cholesterol accumulation in atherosclerotic lesions.

  1. Cholesterol-induced astrocyte activation is associated with increased amyloid precursor protein expression and processing.

    PubMed

    Avila-Muñoz, Evangelina; Arias, Clorinda

    2015-06-19

    Cholesterol is essential for maintaining lipid raft integrity and has been regarded as a crucial regulatory factor for amyloidogenesis in Alzheimer's disease (AD). The vast majority of studies on amyloid precursor protein (APP) metabolism and amyloid β-protein (Aβ) production have focused on neurons. The role of astrocytes remains largely unexplored, despite the presence of activated astrocytes in the brains of most patients with AD and in transgenic models of the disease. The role of cholesterol in Aβ production has been thoroughly studied in neurons and attributed to the participation of lipid rafts in APP metabolism. Thus, in this study, we analyzed the effect of cholesterol loading in astrocytes and analyzed the expression and processing of APP. We found that cholesterol exposure induced astrocyte activation, increased APP content, and enhanced the interaction of APP with BACE-1. These effects were associated with an enrichment of ganglioside GM1-cholesterol patches in the astrocyte membrane and with increased ROS production. GLIA 2015. © 2015 Wiley Periodicals, Inc.

  2. A biosensor for cholesterol based on gold nanoparticles-catalyzed luminol electrogenerated chemiluminescence.

    PubMed

    Zhang, Meihe; Yuan, Ruo; Chai, Yaqin; Chen, Shihong; Zhong, Huaan; Wang, Cun; Cheng, Yinfeng

    2012-02-15

    A novel cholesterol biosensor was prepared based on gold nanoparticles-catalyzed luminol electrogenerated chemiluminescence (ECL). Firstly, l-cysteine-reduced graphene oxide composites were modified on the surface of a glassy carbon electrode. Then, gold nanoparticles (AuNPs) were self-assembled on it. Subsequently, cholesterol oxidase (ChOx) was adsorbed on the surface of AuNPs to construct a cholesterol biosensor. The stepwise fabrication processes were characterized with cyclic voltammetry and atomic force microscopy. The ECL behaviors of the biosensor were also investigated. It was found that AuNPs not only provided larger surface area for higher ChOx loading but also formed the nano-structured interface on the electrode surface to improve the analytical performance of the ECL biosensor for cholesterol. Besides, based on the efficient catalytic ability of AuNPs to luminol ECL, the response of the biosensor to cholesterol was linear range from 3.3 μM to 1.0 mM with a detection limit of 1.1 μM (S/N=3). In addition, the prepared ECL biosensor exhibited satisfying reproducibility, stability and selectivity. Taking into account the advantages of ECL, we confidently expect that ECL would have potential applications in biotechnology and clinical diagnosis.

  3. Intracellular cholesterol-binding proteins enhance HDL-mediated cholesterol uptake in cultured primary mouse hepatocytes.

    PubMed

    Storey, Stephen M; McIntosh, Avery L; Huang, Huan; Landrock, Kerstin K; Martin, Gregory G; Landrock, Danilo; Payne, H Ross; Atshaves, Barbara P; Kier, Ann B; Schroeder, Friedhelm

    2012-04-15

    A major gap in our knowledge of rapid hepatic HDL cholesterol clearance is the role of key intracellular factors that influence this process. Although the reverse cholesterol transport pathway targets HDL to the liver for net elimination of free cholesterol from the body, molecular details governing cholesterol uptake into hepatocytes are not completely understood. Therefore, the effects of sterol carrier protein (SCP)-2 and liver fatty acid-binding protein (L-FABP), high-affinity cholesterol-binding proteins present in hepatocyte cytosol, on HDL-mediated free cholesterol uptake were examined using gene-targeted mouse models, cultured primary hepatocytes, and 22-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino]-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol). While SCP-2 overexpression enhanced NBD-cholesterol uptake, counterintuitively, SCP-2/SCP-x gene ablation also 1) enhanced the rapid molecular phase of free sterol uptake detectable in <1 min and initial rate and maximal uptake of HDL free cholesterol and 2) differentially enhanced free cholesterol uptake mediated by the HDL3, rather than the HDL2, subfraction. The increased HDL free cholesterol uptake was not due to increased expression or distribution of the HDL receptor [scavenger receptor B1 (SRB1)], proteins regulating SRB1 [postsynaptic density protein (PSD-95)/Drosophila disk large tumor suppressor (dlg)/tight junction protein (ZO1) and 17-kDa membrane-associated protein], or other intracellular cholesterol trafficking proteins (steroidogenic acute response protein D, Niemann Pick C, and oxysterol-binding protein-related proteins). However, expression of L-FABP, the single most prevalent hepatic cytosolic protein that binds cholesterol, was upregulated twofold in SCP-2/SCP-x null hepatocytes. Double-immunogold electron microscopy detected L-FABP sufficiently close to SRB1 for direct interaction, similar to SCP-2. These data suggest a role for L-FABP in HDL cholesterol uptake, a finding confirmed with SCP-2

  4. Intracellular cholesterol-binding proteins enhance HDL-mediated cholesterol uptake in cultured primary mouse hepatocytes

    PubMed Central

    Storey, Stephen M.; McIntosh, Avery L.; Huang, Huan; Landrock, Kerstin K.; Martin, Gregory G.; Landrock, Danilo; Payne, H. Ross; Atshaves, Barbara P.; Kier, Ann B.

    2012-01-01

    A major gap in our knowledge of rapid hepatic HDL cholesterol clearance is the role of key intracellular factors that influence this process. Although the reverse cholesterol transport pathway targets HDL to the liver for net elimination of free cholesterol from the body, molecular details governing cholesterol uptake into hepatocytes are not completely understood. Therefore, the effects of sterol carrier protein (SCP)-2 and liver fatty acid-binding protein (L-FABP), high-affinity cholesterol-binding proteins present in hepatocyte cytosol, on HDL-mediated free cholesterol uptake were examined using gene-targeted mouse models, cultured primary hepatocytes, and 22-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino]-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol). While SCP-2 overexpression enhanced NBD-cholesterol uptake, counterintuitively, SCP-2/SCP-x gene ablation also 1) enhanced the rapid molecular phase of free sterol uptake detectable in <1 min and initial rate and maximal uptake of HDL free cholesterol and 2) differentially enhanced free cholesterol uptake mediated by the HDL3, rather than the HDL2, subfraction. The increased HDL free cholesterol uptake was not due to increased expression or distribution of the HDL receptor [scavenger receptor B1 (SRB1)], proteins regulating SRB1 [postsynaptic density protein (PSD-95)/Drosophila disk large tumor suppressor (dlg)/tight junction protein (ZO1) and 17-kDa membrane-associated protein], or other intracellular cholesterol trafficking proteins (steroidogenic acute response protein D, Niemann Pick C, and oxysterol-binding protein-related proteins). However, expression of L-FABP, the single most prevalent hepatic cytosolic protein that binds cholesterol, was upregulated twofold in SCP-2/SCP-x null hepatocytes. Double-immunogold electron microscopy detected L-FABP sufficiently close to SRB1 for direct interaction, similar to SCP-2. These data suggest a role for L-FABP in HDL cholesterol uptake, a finding confirmed with SCP-2

  5. Gallbladder motility and cholesterol crystallization in bile from patients with pigment and cholesterol gallstones.

    PubMed

    Portincasa, P; Di Ciaula, A; Vendemiale, G; Palmieri, V; Moschetta, A; Vanberge-Henegouwen, G P; Palasciano, G

    2000-04-01

    Little is known about gallbladder motility in patients with black pigment stones when compared to cholesterol gallstone patients, or about their relationship to biliary composition, crystallization and stone characteristics. Fasting and postprandial gallbladder volumes were studied by ultrasonography in 49 gallstone patients with pigment (n = 14) or cholesterol (n = 35) stones and 30 healthy controls. After cholecystectomy stone composition, gallbladder wall inflammation, cholesterol saturation index and appearance of platelike cholesterol crystals in bile were evaluated in gallstone patients. Fasting gallbladder volume was significantly (P < 0.05) increased in cholesterol stone patients (31.7 +/- 1.9 mL) but not in pigment stone patients (21.9 +/- 3.1 mL), compared to controls (21.0 +/- 1.5 mL). Postprandial emptying was delayed in patients (half-emptying time: 31 +/- 2 min, 35 +/- 3 min, 24 +/- 2 min in cholesterol stone patients, pigment stone patients and controls, respectively, P < 0.05) and incomplete (residual volume: 43.2 +/- 2.7%, 40.0 +/- 4.3%, 15.8 +/- 1.6% min in cholesterol stone patients, pigment stone patients and controls, respectively, P < 0.05). The inflammation of the gallbladder wall was mild or absent in all cases. Biliary cholesterol saturation index was 152.3 +/- 8.5% and 92.9 +/- 4.8% in patients with cholesterol and pigment stones, respectively (P < 0.01). Whereas cholesterol crystals never appeared during 21 days in biles from patients with pigment stones, crystal observation time in patients with cholesterol gallstone was 5 days (median) and was significantly shorter in patients with multiple (4 days) than in patients with solitary (12 days) cholesterol stones (P = 0.0019). Patients with black pigment stones who do not have excess cholesterol and do not grow cholesterol crystals in bile have decreased gallbladder emptying, although to a lesser extent than patients with cholesterol stones. Thus, gallbladder stasis is likely to put a subset

  6. The Role of Macrophage Lipophagy in Reverse Cholesterol Transport

    PubMed Central

    2017-01-01

    Macrophage cholesterol efflux is a central step in reverse cholesterol transport, which helps to maintain cholesterol homeostasis and to reduce atherosclerosis. Lipophagy has recently been identified as a new step in cholesterol ester hydrolysis that regulates cholesterol efflux, since it mobilizes cholesterol from lipid droplets of macrophages via autophagy and lysosomes. In this review, we briefly discuss recent advances regarding the mechanisms of the cholesterol efflux pathway in macrophage foam cells, and present lipophagy as a therapeutic target in the treatment of atherosclerosis. PMID:28345315

  7. Oxysterols as non-genomic regulators of cholesterol homeostasis

    PubMed Central

    Bielska, Agata; Schlesinger, Paul; Covey, Douglas F.; Ory, Daniel S.

    2011-01-01

    Tight regulation of cellular and plasma cholesterol is crucial to proper cellular functioning because excess free cholesterol is toxic to cells and is associated with atherosclerosis and heart disease. Cellular cholesterol homeostasis is regulated by enzymatically formed oxygenated cholesterol derivatives termed oxysterols. Although the effects of oxysterols on transcriptional pathways are well described, the non-transcriptional mechanisms through which oxysterols acutely modulate cellular cholesterol levels are less well understood. We present emerging evidence suggesting that the membrane biophysical properties of oxysterols underlie their acute cholesterol-regulatory functions and discuss the relevance of these acute effects to cholesterol overload in physiological and pathophysiological states. PMID:22244444

  8. The transport of cholesterol through the plasma in normal man.

    PubMed

    Myant, N B

    1983-09-30

    This review includes a brief account of the routes of entry of cholesterol into the plasma by (a) secretion of lipoproteins and (b) uptake of tissue free cholesterol by lipoproteins in the interstitial fluid, the metabolic transformation undergone by cholesterol within the plasma, with particular reference to the esterification of plasma free cholesterol by lecithin:cholesteryl acyltransferase and the redistribution of esterified cholesterol from high-density to low-density and very-low-density lipoprotein, and the routes by which cholesterol is removed from the plasma by bulk transport. The review end with a balance sheet showing the approximate amounts of cholesterol entering and leaving the plasma by different routes.

  9. Taurine ameliorates cholesterol metabolism by stimulating bile acid production in high-cholesterol-fed rats.

    PubMed

    Murakami, Shigeru; Fujita, Michiko; Nakamura, Masakazu; Sakono, Masanobu; Nishizono, Shoko; Sato, Masao; Imaizumi, Katsumi; Mori, Mari; Fukuda, Nobuhiro

    2016-03-01

    This study was designed to investigate the effects of dietary taurine on cholesterol metabolism in high-cholesterol-fed rats. Male Sprague-Dawley rats were randomly divided into two dietary groups (n = 6 in each group): a high-cholesterol diet containing 0.5% cholesterol and 0.15% sodium cholate, and a high-cholesterol diet with 5% (w/w) taurine. The experimental diets were given for 2 weeks. Taurine supplementation reduced the serum and hepatic cholesterol levels by 37% and 32%, respectively. Faecal excretion of bile acids was significantly increased in taurine-treated rats, compared with untreated rats. Biliary bile acid concentrations were also increased by taurine. Taurine supplementation increased taurine-conjugated bile acids by 61% and decreased glycine-conjugated bile acids by 53%, resulting in a significant decrease in the glycine/taurine (G/T) ratio. Among the taurine-conjugated bile acids, cholic acid and deoxycholic acid were significantly increased. In the liver, taurine supplementation increased the mRNA expression and enzymatic activity of hepatic cholesterol 7α-hydroxylase (CYP7A1), the rate-limiting enzyme for bile acid synthesis, by three- and two-fold, respectively. Taurine also decreased the enzymatic activity of acyl-CoA:cholesterol acyltransferase (ACAT) and microsomal triglyceride transfer protein (MTP). These observations suggest that taurine supplementation increases the synthesis and excretion of taurine-conjugated bile acids and stimulates the catabolism of cholesterol to bile acid by elevating the expression and activity of CYP7A1. This may reduce cholesterol esterification and lipoprotein assembly for very low density lipoprotein (VLDL) secretion, leading to reductions in the serum and hepatic cholesterol levels. © 2016 John Wiley & Sons Australia, Ltd.

  10. Optimization of drug loading to improve physical stability of paclitaxel-loaded long-circulating liposomes.

    PubMed

    Kannan, Vinayagam; Balabathula, Pavan; Divi, Murali K; Thoma, Laura A; Wood, George C

    2015-01-01

    The effect of formulation and process parameters on drug loading and physical stability of paclitaxel-loaded long-circulating liposomes was evaluated. The liposomes were prepared by hydration-extrusion method. The formulation parameters such as total lipid content, cholesterol content, saturated-unsaturated lipid ratio, drug-lipid ratio and process parameters such as extrusion pressure and number of extrusion cycles were studied and their impact on drug loading and physical stability was evaluated. A proportionate increase in drug loading was observed with increase in the total phospholipid content. Cholesterol content and saturated lipid content in the bilayer showed a negative influence on drug loading. The short-term stability evaluation of liposomes prepared with different drug-lipid ratios demonstrated that 1:60 as the optimum drug-lipid ratio to achieve a loading of 1-1.3 mg/mL without the risk of physical instability. The vesicle size decreased with an increase in the extrusion pressure and number of extrusion cycles, but no significant trends were observed for drug loading with changes in process pressure or number of cycles. The optimization of formulation and process parameters led to a physically stable formulation of paclitaxel-loaded long-circulating liposomes that maintain size, charge and integrity during storage.

  11. Dietary glycemic index, dietary glycemic load, blood lipids, and C-reactive protein.

    PubMed

    Levitan, Emily B; Cook, Nancy R; Stampfer, Meir J; Ridker, Paul M; Rexrode, Kathryn M; Buring, Julie E; Manson, JoAnn E; Liu, Simin

    2008-03-01

    Carbohydrate quantity and quality may influence the risk of cardiovascular disease through blood lipid concentrations and inflammation. We measured dietary glycemic index (GI) and dietary glycemic load (GL) among 18137 healthy women > or = 45 years old without diagnosed diabetes using a food-frequency questionnaire. We assayed fasting total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol; LDL/HDL cholesterol ratio; triacylglycerols (TG); and C-reactive protein (CRP). We evaluated associations with dietary GI and GL using a cross-sectional design, adjusting for age, body mass index, lifestyle factors, and other dietary factors. Dietary GI was significantly associated with HDL and LDL cholesterol, LDL/HDL cholesterol ratio, TG, and CRP (comparing top to bottom quintile difference in HDL cholesterol = -2.6 mg/dL, LDL cholesterol = 2.2 mg/dL, LDL/HDL cholesterol ratio = 0.16, TG = 12 mg/dL, and CRP = 0.21 mg/L). Dietary GL was associated with HDL cholesterol, LDL/HDL cholesterol ratio, and TG (comparing top to bottom quintile HDL cholesterol = -4.9 mg/dL, LDL/HDL cholesterol ratio = 0.24, and TG = 13 mg/dL). Differences in blood lipids and CRP between extreme quintiles of dietary GI and GL were small, but may translate into a clinically meaningful difference in cardiovascular risk.

  12. Metabolism of adrenal cholesterol in man

    PubMed Central

    Borkowski, Abraham; Delcroix, Claude; Levin, Sam

    1972-01-01

    The synthesis of adrenal cholesterol, its esterification and the synthesis of the glucocorticosteroid hormones were studied in vitro on human adrenal tissue. It was found that the synthesis of adrenal cholesterol may normally be small in the zona “fasciculata,” particularly when compared with the synthesis of the glucocorticosteroid hormones, that it is several times higher in the zona “reticularis” where esterified cholesterol is less abundant, and that under ACTH stimulation it increases strikingly and proportionally to the degree of esterified adrenal cholesterol depletion. On the other hand, the relative rate of esterification as well as the concentration of free adrenal cholesterol are remarkably stable: they do not differ according to the adrenal zonation and are unaffected by ACTH. Furthermore, from a qualitative point of view, the relative proportions of Δ1 and Δ2 cholesteryl esters formed in situ are similar to those anticipated from their relative concentrations, suggesting that the characteristic fatty acid distribution of the adrenal cholesteryl esters results from an in situ esterification rather than from a selective uptake of the plasma cholesteryl esters. Besides, the in vitro esterification reveals a propensity to the formation of the most unsaturated cholesteryl esters. Regarding hydrocortisone and corticosterone, their synthesis tends to be more elevated in the zona “fasciculata.” Despite its higher cholesterol concentration the zona “fasciculata” should not therefore be viewed as a quiescent functional complement to the zona “reticularis” and the cortical distribution of glucocorticosteroid hormone synthesis is quite distinct from that of adrenal cholesterol synthesis. PMID:4338120

  13. Aspirin Prevention of Cholesterol Gallstone Formation in Prairie Dogs

    NASA Astrophysics Data System (ADS)

    Lee, Sum P.; Carey, Martin C.; Lamont, J. Thomas

    1981-03-01

    When prairie dogs (Cynomys ludovicianus) are fed a diet containing cholesterol, a marked increase in gallbladder mucin secretion parallels the evolution of cholesterol supersaturated bile. Gelation of mucin precedes the precipitation of cholesterol liquid and solid crystals and the development of gallstones. Aspirin given to prairie dogs inhibited mucin hypersecretion and gel accumulation and prevented gallstone formation without influencing the cholesterol content of supersaturated bile. This suggests that gallbladder mucin is a nucleation matrix for cholesterol gallstones.

  14. CHOLESTEROL UPTAKE IN THE SERUM OF NORMAL AND HOSPITALIZED INDIVIDUALS.

    DTIC Science & Technology

    cardiovascular disease . All sera dissolved additional cholesterol. Sera from the hospitalized group dissolved at least as much additional cholesterol as did sera from the normal group. This finding suggests that in atherosclerosis the reserve cholesterol transport capacity is not diminished. This statement, however, must be accepted within the limitations of the method and the unknown effects of therapeutic regimens. The amount of additional cholesterol dissolved by a sample of serum is not correlated with the original concentration of cholesterol in the serum.

  15. Cholesterol and markers of cholesterol turnover in multiple sclerosis: relationship with disease outcomes.

    PubMed

    Zhornitsky, Simon; McKay, Kyla A; Metz, Luanne M; Teunissen, Charlotte E; Rangachari, Manu

    2016-01-01

    Multiple sclerosis (MS) is a chronic central nervous system disease that is associated with progressive loss of myelin and subsequent axonal degeneration. Cholesterol is an essential component of mammalian cellular and myelin membranes. In this systematic review, we examined the relationship between levels of cholesterol and markers of cholesterol turnover in circulation and/or cerebrospinal fluid (CSF) and disease outcomes in adults with clinically isolated syndrome (CIS) or confirmed MS. Studies suggest that elevated levels of circulating low density lipoprotein cholesterol (LDL), total cholesterol, and particularly, apolipoprotein B and oxidized LDL are associated with adverse clinical and MRI outcomes in MS. These relationships were observed as early as CIS. The studies also suggest that oxysterols, cholesterol precursors, and apolipoprotein E may be markers of specific disease processes in MS, but more research is required to elucidate these processes and relationships. Taken together, the data indicate that cholesterol and markers of cholesterol turnover have potential to be used clinically as biomarkers of disease activity and may even be implicated in the pathogenesis of MS.

  16. Prevention of cholesterol gallstones by inhibiting hepatic biosynthesis and intestinal absorption of cholesterol

    PubMed Central

    Wang, Helen H; Portincasa, Piero; de Bari, Ornella; Liu, Kristina J; Garruti, Gabriella; Neuschwander-Tetri, Brent A; Wang, David Q.-H

    2013-01-01

    Cholesterol cholelithiasis is a multifactorial disease influenced by a complex interaction of genetic and environmental factors, and represents a failure of biliary cholesterol homeostasis in which the physical-chemical balance of cholesterol solubility in bile is disturbed. The primary pathophysiologic event is persistent hepatic hypersecretion of biliary cholesterol, which has both hepatic and small intestinal components. The majority of the environmental factors are probably related to Western-type dietary habits, including excess cholesterol consumption. Laparoscopic cholecystectomy, one of the most commonly performed surgical procedures in the US, is nowadays a major treatment for gallstones. However, it is invasive and can cause surgical complications, and not all patients with symptomatic gallstones are candidates for surgery. The hydrophilic bile acid, ursodeoxycholic acid (UDCA) has been employed as first-line pharmacological therapy in a subgroup of symptomatic patients with small, radiolucent cholesterol gallstones. Long-term administration of UDCA can promote the dissolution of cholesterol gallstones. However, the optimal use of UDCA is not always achieved in clinical practice because of failure to titrate the dose adequately. Therefore, the development of novel, effective, and noninvasive therapies is crucial for reducing the costs of health care associated with gallstones. In this review, we summarize recent progress in investigating the inhibitory effects of ezetimibe and statins on intestinal absorption and hepatic biosynthesis of cholesterol, respectively, for the treatment of gallstones, as well as in elucidating their molecular mechanisms by which combination therapy could prevent this very common liver disease worldwide. PMID:23419155

  17. Regulation of hepatic cholesterol synthesis by a novel protein (SPF) that accelerates cholesterol biosynthesis.

    PubMed

    Shibata, Norihito; Jishage, Kou-ichi; Arita, Makoto; Watanabe, Miho; Kawase, Yosuke; Nishikawa, Kiyotaka; Natori, Yasuhiro; Inoue, Hiroyasu; Shimano, Hitoshi; Yamada, Nobuhiro; Tsujimoto, Masafumi; Arai, Hiroyuki

    2006-12-01

    Supernatant protein factor (SPF) is a novel cholesterol biosynthesis-accelerating protein expressed in liver and small intestine. Here, we report on the physiological role of SPF by using Spf-deficient mice. Although plasma cholesterol levels were similar in chow-fed Spf-/- and wild-type (WT) mice, fasting significantly decreased plasma cholesterol levels in Spf-/- mice but not in WT mice. While fasting reduced hepatic cholesterol synthesis rate in WT mice, a more pronounced reduction was observed in Spf-/- mice. The expression of cholesterogenic enzymes was dramatically suppressed by fasting both in WT and Spf-/- mice. In contrast, hepatic SPF expression of WT mice was up-regulated by fasting in peroxisome proliferator-activated receptor alpha (PPAR-alpha)-dependent manner. These results indicate that in WT mice, the decrease of hepatic cholesterol synthesis under fasting conditions is at least in part compensated by SPF up-regulation. Fibrates, which function as a PPAR-alpha agonist and are widely used as hypotriglycemic drugs, reduced hepatic cholesterol synthesis and plasma cholesterol levels by approximately one-half in Spf-/- mice but not in WT mice. These findings suggest that co-administration of fibrates and an SPF inhibitor may reduce not only plasma triglyceride but also cholesterol levels, indicating that SPF is a promising hypocholesterolemic drug target.

  18. Cholesterol content and methods for cholesterol determination in meat and poultry

    USDA-ARS?s Scientific Manuscript database

    Available data for cholesterol content of beef, pork, poultry, and processed meat products were reported. Although the cholesterol concentration in meat and poultry can be influenced by various factors, effects of animal species, muscle fiber type, and muscle fat content are focused on in this revi...

  19. A novel alkyne cholesterol to trace cellular cholesterol metabolism and localization[S

    PubMed Central

    Hofmann, Kristina; Thiele, Christoph; Schött, Hans-Frieder; Gaebler, Anne; Schoene, Mario; Kiver, Yuriy; Friedrichs, Silvia; Lütjohann, Dieter; Kuerschner, Lars

    2014-01-01

    Cholesterol is an important lipid of mammalian cells and plays a fundamental role in many biological processes. Its concentration in the various cellular membranes differs and is tightly regulated. Here, we present a novel alkyne cholesterol analog suitable for tracing both cholesterol metabolism and localization. This probe can be detected by click chemistry employing various reporter azides. Alkyne cholesterol is accepted by cellular enzymes from different biological species (Brevibacterium, yeast, rat, human) and these enzymes include cholesterol oxidases, hydroxylases, and acyl transferases that generate the expected metabolites in in vitro and in vivo assays. Using fluorescence microscopy, we studied the distribution of cholesterol at subcellular resolution, detecting the lipid in the Golgi and at the plasma membrane, but also in the endoplasmic reticulum and mitochondria. In summary, alkyne cholesterol represents a versatile, sensitive, and easy-to-use tool for tracking cellular cholesterol metabolism and localization as it allows for manifold detection methods including mass spectrometry, thin-layer chromatography/fluorography, and fluorescence microscopy. PMID:24334219

  20. Cholesterol oxidase from Bordetella species promotes irreversible cell apoptosis in lung adenocarcinoma by cholesterol oxidation

    PubMed Central

    Liu, J; Xian, G; Li, M; Zhang, Y; Yang, M; Yu, Y; Lv, H; Xuan, S; Lin, Y; Gao, L

    2014-01-01

    Cholesterol oxidase (COD), an enzyme catalyzing the oxidation of cholesterol, has been applied to track the distribution of membrane cholesterol. Little investigations about the effect of COD on tumor cells have been performed. In the present study, we provided evidence that COD from Bordetella species (COD-B), induced apoptosis of lung cancer cells in vitro and in vivo. COD-B treatment inhibited Akt and ERK1/2 phosphorylation in dose- and time-dependent manner, which was not reversed and was even aggravated by cholesterol addition. Further investigation indicated that COD-B treatment promoted the generation of reactive oxygen species (ROS) and that cholesterol addition further elevated ROS levels. Moreover, COD-B treatment resulted in JNK and p38 phosphorylation, downregulation of Bcl-2, upregulation of Bax, activated caspase-3 and cytochrome C release, which likely responded to freshly produced hydrogen peroxide that accompanied cholesterol oxidation. Catalase pretreatment could only partially prevent COD-B-induced events, suggesting that catalase inhibited H2O2-induced signal transduction but had little effect on signal pathways involved in cholesterol depletion. Our results demonstrated that COD-B led to irreversible cell apoptosis by decreasing cholesterol content and increasing ROS level. In addition, COD-B may be a promising candidate for a novel anti-tumor therapy. PMID:25118932

  1. CHOLESTEROL HOMEOSTASIS AND THE ESCAPE TENDENCY (ACTIVITY) OF PLASMA MEMBRANE CHOLESTEROL

    PubMed Central

    Lange, Yvonne; Steck, Theodore L.

    2008-01-01

    We review evidence that sterols can form stoichiometric complexes with certain bilayer phospholipids, and sphingomyelin in particular. These complexes appear to be the basis for the formation of condensed and ordered liquid phases, (micro)domains and/or rafts in both artificial and biological membranes. The sterol content of a membrane can exceed the complexing capacity of its phospholipids. The excess, uncomplexed membrane sterol molecules have a relatively high escape tendency, also referred to as fugacity or chemical activity (and, here, simply activity). Cholesterol is also activated when certain membrane intercalating amphipaths displace it from the phospholipid complexes. Active cholesterol projects from the bilayer and is therefore highly susceptible to attack by cholesterol oxidase. Similarly, active cholesterol rapidly exits the plasma membrane to extracellular acceptors such as cyclodextrin and high-density lipoproteins. For the same reason, the pool of cholesterol in the ER (endoplasmic reticulum) increases sharply when cell surface cholesterol is incremented above the physiological set-point; i.e., equivalence with the complexing phospholipids. As a result, the escape tendency of the excess cholesterol not only returns the plasma membrane bilayer to its set point but also serves as a feedback signal to intracellular homeostatic elements to down-regulate cholesterol accretion. PMID:18423408

  2. Potential of BODIPY-cholesterol for analysis of cholesterol transport and diffusion in living cells.

    PubMed

    Wüstner, Daniel; Lund, Frederik W; Röhrl, Clemens; Stangl, Herbert

    2016-01-01

    Cholesterol is an abundant and important lipid component of cellular membranes. Analysis of cholesterol transport and diffusion in living cells is hampered by the technical challenge of designing suitable cholesterol probes which can be detected for example by optical microscopy. One strategy is to use intrinsically fluorescent sterols, as dehydroergosterol (DHE), having minimal chemical alteration compared to cholesterol but giving low fluorescence signals in the UV region of the spectrum. Alternatively, one can use dye-tagged cholesterol analogs and in particular BODIPY-cholesterol (BChol), whose synthesis and initial characterization was pioneered by Robert Bittman. Here, we give a general overview of the properties and applications but also limitations of BODIPY-tagged cholesterol probes for analyzing intracellular cholesterol trafficking. We describe our own experiences and collaborative efforts with Bob Bittman for studying diffusion in the plasma membrane (PM) and uptake of BChol in a quantitative manner. For that purpose, we used a variety of fluorescence approaches including fluorescence correlation spectroscopy and its imaging variants, fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP). We also describe pulse-chase studies from the PM using BChol in direct comparison to DHE. Based on the gathered imaging data, we present a two-step kinetic model for sterol transport between PM and recycling endosomes. In addition, we highlight the suitability of BChol for determining transport of lipoprotein-derived sterol using electron microscopy (EM) and show that this approach ideally complements fluorescence studies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. Molecular events linking cholesterol to Alzheimer’s disease and inclusion body myositis in a rabbit model

    PubMed Central

    Liu, Qing Yan; Koukiekolo, Roger; Zhang, Dong Ling; Smith, Brandon; Ly, Dao; Lei, Joy X; Ghribi, Othman

    2016-01-01

    Alzheimer’s disease (AD) is the most common neurodegenerative disorder, characterized by cognitive impairment and dementia, resulting from progressive synaptic dysfunction, loss and neuronal cell death. Inclusion body myositis (IBM) is a skeletal muscle degenerative disease, displaying progressive proximal and distal muscle weakness, in association with muscle fiber atrophy, degeneration and death. Studies have shown that the late onset version of AD (LOAD) and sporadic IBM (sIBM) in muscle share many pathological features, including the presence of extracellular plaques of β-amyloid peptides and intracellular tangles of hyperphosphorylated tau proteins. High blood cholesterol is suggested to be a risk factor for LOAD. Many neuropathological changes of LOAD can be reproduced by feeding rabbits a 2% enriched cholesterol diet for 12 weeks. The cholesterol fed rabbit model also simultaneously develops sIBM like pathology, which makes it an ideal model to study the molecular mechanisms common to the development of both diseases. In the present study, we determined the changes of gene expression in rabbit brain and muscle during the progression of LOAD and sIBM pathology using a custom rabbit nucleotide microarray, followed by qRT-PCR analyses. Out of 869 unique transcripts screened, 47 genes showed differential expression between the control and the cholesterol-treated group during the 12 week period and 19 changed transcripts appeared to be common to LOAD and sIBM. The most notable changes are the upregulation of the hemoglobin gene family and the downregulation of the genes required for mitochondrial oxidative phosphorylation in both brain and muscle tissues throughout the time course. The significant overlap on the changes of gene expression in the brain and muscle of rabbits fed with cholesterol-enriched diet supports the notion that LOAD and sIBM may share a common etiology. PMID:27073745

  4. [Trans-intestinal cholesterol excretion (TICE): a new route for cholesterol excretion].

    PubMed

    Blanchard, Claire; Moreau, François; Cariou, Bertrand; Le May, Cédric

    2014-10-01

    The small intestine plays a crucial role in dietary and biliary cholesterol absorption, as well as its lymphatic secretion as chylomicrons (lipoprotein exogenous way). Recently, a new metabolic pathway called TICE (trans-intestinal excretion of cholesterol) that plays a central role in cholesterol metabolism has emerged. TICE is an inducible way, complementary to the hepatobiliary pathway, allowing the elimination of the plasma cholesterol directly into the intestine lumen through the enterocytes. This pathway is poorly characterized but several molecular actors of TICE have been recently identified. Although it is a matter of debate, two independent studies suggest that TICE is involved in the anti-atherogenic reverse cholesterol transport pathway. Thus, TICE is an innovative drug target to reduce -cardiovascular diseases.

  5. A diet rich in leafy vegetable fiber improves cholesterol metabolism in high-cholesterol fed rats.

    PubMed

    Ezz El-Arab, A M

    2009-10-01

    In the present study, the hypocholesterolemic effect of leaf vegetable (Jew's mallow) was studied in high-cholesterol fed rats. The animals were fed diets supplemented with cholesterol (0.25%) for 4 weeks. Leaf vegetable diet produced an important hypocholesterolemic action: it led to a significant lowering (p<0.05) of cholesterol in the plasma and liver, as well as of the atherogenic index and a significant increase (p<0.05) in cecal short chain fatty acids, with respect to the control group. Concurrently, total fecal neutral sterols in the excretion increased (p<0.05) and apparent absorption of dietary cholesterol was significantly depressed (-58%). The consumption of leaf vegetable (Jew's mallow) with a hypercholesterolemic diet improved the lipidemic profile and increased excretion of the total cholesterol end-products.

  6. Effect of Inhibition of Intestinal Cholesterol Absorption on the Prevention of Cholesterol Gallstone Formation.

    PubMed

    Portincasa, Piero; Wang, David Q-H

    2017-01-01

    Cholesterol cholelithiasis is a multifactorial hepatobiliary disease. Interactions between genetic and environmental factors play a critical role in biliary cholesterol homeostasis and its imbalance enhances cholelithogenesis. In patients developing symptoms or complications of gallstone disease, laparoscopic cholecystectomy is recommended for treatment of gallstones. In a subgroup of patients with small, radiolucent pure cholesterol gallstones, the hydrophilic bile acid, ursodeoxycholic acid (UDCA) is still considered the only pharmacological therapy able to induce oral litholysis. Identifying novel and effective pharmacological therapies is being investigated. We propose that the specific intestinal Niemann-Pick C1-like 1 protein inhibitor ezetimibe is a potential agent for preventing gallstone formation by reducing bioavailability of intestine- derived cholesterol to the liver for biliary secretion and desaturating bile through the inhibition of intestinal absorption of cholesterol. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  7. NPC1, intracellular cholesterol trafficking and atherosclerosis.

    PubMed

    Yu, Xiao-Hua; Jiang, Na; Yao, Ping-Bo; Zheng, Xi-Long; Cayabyab, Francisco S; Tang, Chao-Ke

    2014-02-15

    Post-lysosomal cholesterol trafficking is an important, but poorly understood process that is essential to maintain lipid homeostasis. Niemann-Pick type C1 (NPC1), an integral membrane protein on the limiting membrane of late endosome/lysosome (LE/LY), is known to accept cholesterol from NPC2 and then mediate cholesterol transport from LE/LY to endoplasmic reticulum (ER) and plasma membrane in a vesicle- or oxysterol-binding protein (OSBP)-related protein 5 (ORP5)-dependent manner. Mutations in the NPC1 gene can be found in the majority of NPC patients, who accumulate massive amounts of cholesterol and other lipids in the LE/LY due to a defect in intracellular lipid trafficking. Liver X receptor (LXR) is the major positive regulator of NPC1 expression. Atherosclerosis is the pathological basis of coronary heart disease, one of the major causes of death worldwide. NPC1 has been shown to play a critical role in the atherosclerotic progression. In this review, we have summarized the role of NPC1 in regulating intracellular cholesterol trafficking and atherosclerosis.

  8. Lipoproteins, cholesterol homeostasis and cardiac health

    PubMed Central

    Daniels, Tyler F.; Killinger, Karen M.; Michal, Jennifer J.; Wright Jr., Raymond W.; Jiang, Zhihua

    2009-01-01

    Cholesterol is an essential substance involved in many functions, such as maintaining cell membranes, manufacturing vitamin D on surface of the skin, producing hormones, and possibly helping cell connections in the brain. When cholesterol levels rise in the blood, they can, however, have dangerous consequences. In particular, cholesterol has generated considerable notoriety for its causative role in atherosclerosis, the leading cause of death in developed countries around the world. Homeostasis of cholesterol is centered on the metabolism of lipoproteins, which mediate transport of the lipid to and from tissues. As a synopsis of the major events and proteins that manage lipoprotein homeostasis, this review contributes to the substantial attention that has recently been directed to this area. Despite intense scrutiny, the majority of phenotypic variation in total cholesterol and related traits eludes explanation by current genetic knowledge. This is somewhat disappointing considering heritability estimates have established these traits as highly genetic. Thus, the continued search for candidate genes, mutations, and mechanisms is vital to our understanding of heart disease at the molecular level. Furthermore, as marker development continues to predict risk of vascular illness, this knowledge has the potential to revolutionize treatment of this leading human disease. PMID:19584955

  9. LOADING DEVICE

    DOEpatents

    Ohlinger, L.A.

    1958-10-01

    A device is presented for loading or charging bodies of fissionable material into a reactor. This device consists of a car, mounted on tracks, into which the fissionable materials may be placed at a remote area, transported to the reactor, and inserted without danger to the operating personnel. The car has mounted on it a heavily shielded magazine for holding a number of the radioactive bodies. The magazine is of a U-shaped configuration and is inclined to the horizontal plane, with a cap covering the elevated open end, and a remotely operated plunger at the lower, closed end. After the fissionable bodies are loaded in the magazine and transported to the reactor, the plunger inserts the body at the lower end of the magazine into the reactor, then is withdrawn, thereby allowing gravity to roll the remaining bodies into position for successive loading in a similar manner.

  10. Enzymatic Quantification of Cholesterol and Cholesterol Esters from Silicone Hydrogel Contact Lenses

    PubMed Central

    Pucker, Andrew D.; Thangavelu, Mirunalni

    2010-01-01

    Purpose. The purpose of this work was to develop an enzymatic method of quantification of cholesterol and cholesterol esters derived from contact lenses, both in vitro and ex vivo. Methods. Lotrafilcon B (O2 Optix; CIBA Vision, Inc., Duluth, GA) and galyfilcon A (Acuvue Advance; Vistakon, Inc., Jacksonville, FL) silicone hydrogel contact lenses were independently incubated in cholesterol oleate solutions varying in concentrations. After incubation, the lenses were removed and underwent two separate 2:1 chloroform-methanol extractions. After in vitro studies, 10 human subjects wore both lotrafilcon B and galyfilcon A contact lenses for 7 days. The lenses also underwent two separate 2:1 chloroform-methanol extractions. All in vitro and ex vivo samples were quantified with a cholesterol esterase enzymatic reaction. Results. Calibration curves from quantifications of in vitro contact lens samples soaked in successively decreasing concentrations of cholesterol oleate yielded coefficients of determination (R2) of 0.99 (lotrafilcon B) and 0.97 (galyfilcon A). For in vitro contact lens samples, galyfilcon A was associated with an average cholesterol oleate extraction of 39.85 ± 48.65 μg/lens, whereas lotrafilcon B was associated with 5.86 ± 3.36 μg/lens (P = 0.05) across both extractions and all incubation concentrations. For ex vivo contact lens samples, there was significantly more cholesterol and cholesterol esters deposited on galyfilcon A (5.77 ± 1.87 μg/lens) than on lotrafilcon B (2.03 ± 1.62 μg/lens; P = 0.0005). Conclusions. This is an efficient and simple method of quantifying total cholesterol extracted from silicone hydrogel contact lenses and, potentially, the meibum and/or tear film. Certain silicone hydrogel materials demonstrate more affinity for cholesterol and its esters than do others. PMID:20089871

  11. Enzymatic quantification of cholesterol and cholesterol esters from silicone hydrogel contact lenses.

    PubMed

    Pucker, Andrew D; Thangavelu, Mirunalni; Nichols, Jason J

    2010-06-01

    The purpose of this work was to develop an enzymatic method of quantification of cholesterol and cholesterol esters derived from contact lenses, both in vitro and ex vivo. Lotrafilcon B (O2 Optix; CIBA Vision, Inc., Duluth, GA) and galyfilcon A (Acuvue Advance; Vistakon, Inc., Jacksonville, FL) silicone hydrogel contact lenses were independently incubated in cholesterol oleate solutions varying in concentrations. After incubation, the lenses were removed and underwent two separate 2:1 chloroform-methanol extractions. After in vitro studies, 10 human subjects wore both lotrafilcon B and galyfilcon A contact lenses for 7 days. The lenses also underwent two separate 2:1 chloroform-methanol extractions. All in vitro and ex vivo samples were quantified with a cholesterol esterase enzymatic reaction. Calibration curves from quantifications of in vitro contact lens samples soaked in successively decreasing concentrations of cholesterol oleate yielded coefficients of determination (R(2)) of 0.99 (lotrafilcon B) and 0.97 (galyfilcon A). For in vitro contact lens samples, galyfilcon A was associated with an average cholesterol oleate extraction of 39.85 +/- 48.65 microg/lens, whereas lotrafilcon B was associated with 5.86 +/- 3.36 microg/lens (P = 0.05) across both extractions and all incubation concentrations. For ex vivo contact lens samples, there was significantly more cholesterol and cholesterol esters deposited on galyfilcon A (5.77 +/- 1.87 microg/lens) than on lotrafilcon B (2.03 +/- 1.62 microg/lens; P = 0.0005). This is an efficient and simple method of quantifying total cholesterol extracted from silicone hydrogel contact lenses and, potentially, the meibum and/or tear film. Certain silicone hydrogel materials demonstrate more affinity for cholesterol and its esters than do others.

  12. Free cholesterol and cholesterol esters in bovine oocytes: Implications in survival and membrane raft organization after cryopreservation.

    PubMed

    Buschiazzo, Jorgelina; Ríos, Glenda L; Canizo, Jesica R; Antollini, Silvia S; Alberio, Ricardo H

    2017-01-01

    Part of the damage caused by cryopreservation of mammalian oocytes occurs at the plasma membrane. The addition of cholesterol to cell membranes as a strategy to make it more tolerant to cryopreservation has been little addressed in oocytes. In order to increase the survival of bovine oocytes after cryopreservation, we proposed not only to increase cholesterol level of oocyte membranes before vitrification but also to remove the added cholesterol after warming, thus recovering its original level. Results from our study showed that modulation of membrane cholesterol by methyl-β-cyclodextrin (MβCD) did not affect the apoptotic status of oocytes and improved viability after vitrification yielding levels of apoptosis closer to those of fresh oocytes. Fluorometric measurements based on an enzyme-coupled reaction that detects both free cholesterol (membrane) and cholesteryl esters (stored in lipid droplets), revealed that oocytes and cumulus cells present different levels of cholesterol depending on the seasonal period. Variations at membrane cholesterol level of oocytes were enough to account for the differences found in total cholesterol. Differences found in total cholesterol of cumulus cells were explained by the differences found in both the content of membrane cholesterol and of cholesterol esters. Cholesterol was incorporated into the oocyte plasma membrane as evidenced by comparative labeling of a fluorescent cholesterol. Oocytes and cumulus cells increased membrane cholesterol after incubation with MβCD/cholesterol and recovered their original level after cholesterol removal, regardless of the season. Finally, we evaluated the effect of vitrification on the putative raft molecule GM1. Cholesterol modulation also preserved membrane organization by maintaining ganglioside level at the plasma membrane. Results suggest a distinctive cholesterol metabolic status of cumulus-oocyte complexes (COCs) among seasons and a dynamic organizational structure of cholesterol

  13. Localization of cholesterol in sphingomyelinase-treated fibroblasts.

    PubMed

    Pörn, M I; Slotte, J P

    1995-05-15

    The distribution of cellular unesterified cholesterol was studied in fibroblasts, which had been depleted of plasma membrane sphingomyelin by exposure to exogenous sphingomyelinase. This treatment has previously been shown to induce an increase in cholesterol esterification, a decrease in the biosynthesis of cholesterol, and a decreased susceptibility of cell cholesterol to oxidation with cholesterol oxidase. When the cellular localization of cholesterol was studied with fluorescent filipin staining, sphingomyelin depletion did not cause any visible changes in the filipin-cholesterol staining pattern, suggesting that the major part of cellular cholesterol was retained in the plasma membrane after sphingomyelinase treatment. After the oxidation of cell-surface cholesterol with cholesterol oxidase, the plasma membrane was no longer stained by filipin, but the plasma membrane cholesterol of sphingomyelin-depleted cells appeared to be resistant to oxidation with cholesterol oxidase when sphingomyelinase was used as an oxidation-promoting agent. However, the use of hypotonic buffer or phosphatidylcholine-specific phospholipase C together with cholesterol oxidase resulted in a complete oxidation of the cell-surface cholesterol in sphingomyelin-depleted cells, as evidenced by the filipin-cholesterol staining pattern. Similar results were obtained when [3H]cholesterol-labelled fibroblasts were used for determination of the susceptibility to cholesterol oxidation. The kinetics of [3H]cholesterol oxidation in sphingomyelin-depleted cells with cholesterol oxidase in hypotonic buffer indicated that approximately 85% of the cellular cholesterol still resided in the plasma membrane after sphingomyelin depletion. These results are contradictory to earlier reports on sphingomyelinase-induced changes in cellular cholesterol distribution and suggest that minor changes in the kinetics of cholesterol transport from the plasma membrane to the endoplasmic reticulum may be responsible

  14. Localization of cholesterol in sphingomyelinase-treated fibroblasts.

    PubMed Central

    Pörn, M I; Slotte, J P

    1995-01-01

    The distribution of cellular unesterified cholesterol was studied in fibroblasts, which had been depleted of plasma membrane sphingomyelin by exposure to exogenous sphingomyelinase. This treatment has previously been shown to induce an increase in cholesterol esterification, a decrease in the biosynthesis of cholesterol, and a decreased susceptibility of cell cholesterol to oxidation with cholesterol oxidase. When the cellular localization of cholesterol was studied with fluorescent filipin staining, sphingomyelin depletion did not cause any visible changes in the filipin-cholesterol staining pattern, suggesting that the major part of cellular cholesterol was retained in the plasma membrane after sphingomyelinase treatment. After the oxidation of cell-surface cholesterol with cholesterol oxidase, the plasma membrane was no longer stained by filipin, but the plasma membrane cholesterol of sphingomyelin-depleted cells appeared to be resistant to oxidation with cholesterol oxidase when sphingomyelinase was used as an oxidation-promoting agent. However, the use of hypotonic buffer or phosphatidylcholine-specific phospholipase C together with cholesterol oxidase resulted in a complete oxidation of the cell-surface cholesterol in sphingomyelin-depleted cells, as evidenced by the filipin-cholesterol staining pattern. Similar results were obtained when [3H]cholesterol-labelled fibroblasts were used for determination of the susceptibility to cholesterol oxidation. The kinetics of [3H]cholesterol oxidation in sphingomyelin-depleted cells with cholesterol oxidase in hypotonic buffer indicated that approximately 85% of the cellular cholesterol still resided in the plasma membrane after sphingomyelin depletion. These results are contradictory to earlier reports on sphingomyelinase-induced changes in cellular cholesterol distribution and suggest that minor changes in the kinetics of cholesterol transport from the plasma membrane to the endoplasmic reticulum may be responsible

  15. Monensin and brefeldin A inhibit high density lipoprotein-mediated cholesterol efflux from cholesterol-enriched cells. Implications for intracellular cholesterol transport.

    PubMed

    Mendez, A J

    1995-03-17

    Mechanisms and pathways of excess cholesterol removal from intracellular sites of accumulation to extracellular cholesterol acceptors remain poorly defined. To gain further insights, compounds known to affect cellular protein transport pathways were tested for their effects on high density lipoprotein (HDL)-mediated cholesterol efflux from cultured cells enriched with cholesterol. Monensin, nigericin, and brefeldin A inhibited the ability of HDL to decrease cellular cholesterol esterification, stimulate sterol biosynthesis, and promote the efflux of labeled cholesterol and cholesterol mass from fibroblasts and smooth muscle cells. HDL-mediated decrease in cell cholesterol esterification was inhibited up to 80% by these compounds compared with control incubations over an HDL concentration of 5-100 micrograms/ml and up to 18 h of incubation. Up-regulation of sterol biosynthesis after depletion of cell cholesterol by HDL increased over 10-fold; however, inclusion of monensin or brefeldin A during the incubation completely prevented the increase of sterol biosynthesis by HDL. Efflux of [3H]cholesterol to HDL from prelabeled cells was inhibited up to 40% by these compounds, and this effect persisted when cholesterol esterification was blocked. Similarly, monensin and brefeldin A inhibited up to 50% of HDL-mediated cholesterol mass efflux relative to controls. Treatment of cells with cholesterol oxidase demonstrated an increase of intracellular cholesterol after exposure to monensin or nigericin and to a lesser extent with brefeldin A. These data show that monensin, nigericin, and brefeldin A sequester cholesterol from sites normally available for efflux by HDL. Since these compounds act by disruption of Golgi complex structure and function, a role for this intracellular organelle in transport of cholesterol between intracellular sites and the plasma membrane for eventual removal by extracellular acceptors such as HDL is suggested.

  16. PPARγ activation redirects macrophage cholesterol from fecal excretion to adipose tissue uptake in mice via SR-BI

    PubMed Central

    Toh, Sue-Anne; Millar, John S.; Billheimer, Jeffrey; Fuki, Ilia; Naik, Snehal U.; Macphee, Colin; Walker, Max; Rader, Daniel J.

    2011-01-01

    PPARγ agonists, used in the treatment of Type 2 diabetes, can raise HDL-cholesterol, therefore could potentially stimulate macrophage-to-feces reverse cholesterol transport (RCT). We aimed to test whether PPARγ activation promotes macrophage RCT in vivo. Macrophage RCT was assessed in mice using cholesterol loaded/3H-cholesterol labeled macrophages. PPARγ agonist GW7845 (20 mg/kg/day) did not change 3H-tracer plasma appearance, but surprisingly decreased fecal 3H-free sterol excretion by 43% (P < 0.01) over 48 h. Total free cholesterol efflux from macrophages to serum (collected from control and GW7845 groups) was not different, although ABCA1-mediated efflux was significantly higher with GW7845. To determine the effect of PPARγ activation on HDL cholesterol uptake by different tissues, the metabolic fate of HDL labeled with 3H-cholesteryl ether (CE) was also measured. We observed two-fold increase in HDL derived 3H-CE uptake by adipose tissue (P < 0.005) with concomitant 22% decrease in HDL derived 3H-CE uptake by the liver (P < 0.05) in GW7845 treated wild type mice. This was associated with a significant increase in SR-BI protein expression in adipose tissue, but not liver. The same experiment in SR-BI knockout mice, showed no difference in HDL derived 3H-CE uptake by adipose tissue or liver. In conclusion, PPARγ activation decreases the fecal excretion of macrophage derived cholesterol in mice. This is not due to inhibition of cholesterol efflux from macrophages, but rather involves redirection of effluxed cholesterol from liver towards adipose tissue uptake via SR-BI. This represents a novel mechanism for regulation of RCT and may extend the therapeutic implications of these ligands. PMID:21291868

  17. The Interpretation of Cholesterol Balance Derived Synthesis Data and Surrogate Noncholesterol Plasma Markers for Cholesterol Synthesis under Lipid Lowering Therapies

    PubMed Central

    Stellaard, Frans

    2017-01-01

    The cholesterol balance procedure allows the calculation of cholesterol synthesis based on the assumption that loss of endogenous cholesterol via fecal excretion and bile acid synthesis is compensated by de novo synthesis. Under ezetimibe therapy hepatic cholesterol is diminished which can be compensated by hepatic de novo synthesis and hepatic extraction of plasma cholesterol. The plasma lathosterol concentration corrected for total cholesterol concentration (R_Lath) as a marker of de novo cholesterol synthesis is increased during ezetimibe treatment but unchanged under treatment with ezetimibe and simvastatin. Cholesterol balance derived synthesis data increase during both therapies. We hypothesize the following. (1) The cholesterol balance data must be applied to the hepatobiliary cholesterol pool. (2) The calculated cholesterol synthesis value is the sum of hepatic de novo synthesis and the net plasma—liver cholesterol exchange rate. (3) The reduced rate of biliary cholesterol absorption is the major trigger for the regulation of hepatic cholesterol metabolism under ezetimibe treatment. Supportive experimental and literature data are presented that describe changes of cholesterol fluxes under ezetimibe, statin, and combined treatments in omnivores and vegans, link plasma R_Lath to liver function, and define hepatic de novo synthesis as target for regulation of synthesis. An ezetimibe dependent direct hepatic drug effect cannot be excluded. PMID:28321334

  18. Extracellular cholesterol-rich microdomains generated by human macrophages and their potential function in reverse cholesterol transport

    PubMed Central

    Ong, Daniel S.; Anzinger, Joshua J.; Leyva, Francisco J.; Rubin, Noa; Addadi, Lia; Kruth, Howard S.

    2010-01-01

    Previous studies have shown that cholesterol in atherosclerotic plaques is present in both intracellular and extracellular forms. In the current study, we investigated a mechanism for extracellular cholesterol accumulation and examined the capacity of this pool of cholesterol to be removed by cholesterol acceptors, a step in reverse cholesterol transport. Human monocyte-derived macrophages differentiated with macrophage-colony stimulating factor were incubated with acetylated LDL to allow cholesterol enrichment and processing. These macrophages were subsequently labeled with a monoclonal antibody that specifically detects ordered cholesterol arrays, revealing the presence of unesterified cholesterol-rich microdomains on the cell surfaces and in the extracellular matrix. Similar unesterified cholesterol-rich microdomains were present in human atherosclerotic plaques. Actin microfilaments functioned in microdomain deposition or maintenance, and Src family kinases regulated transfer of these microdomains from the cell surface onto the extracellular matrix. Mediators of reverse cholesterol transport, apolipoprotein A-I (apoA-I), and HDL were capable of removing these extracellular un-esterified cholesterol-rich microdomains. However, apoA-I removed the microdomains only when macrophages were present. ApoA-I removal of microdomains was blocked by glyburide and inhibitor of ATP-binding cassette transporter A1 (ABCA1) function. In summary, cultures of cholesterol-enriched human monocyte-derived macrophages generate extracellular unesterified cholesterol-rich microdomains, which can subsequently be removed by cholesterol acceptors and therefore potentially function in reverse cholesterol transport. PMID:20421591

  19. History of the cholesterol controversy in Britain.

    PubMed

    Thompson, G R

    2009-02-01

    The lipid hypothesis, the concept that cholesterol plays a causal role in atherosclerosis and cardiovascular disease, has been the subject of a controversy which started in the 1950s, peaked in the 1970s and 80s and then subsided in the 1990s. It was finally resolved by the positive outcome of the Scandinavian Simvastatin Survival Study, the first of 14 prevention trials using statins which showed that lowering cholesterol reduced both cardiovascular events and total mortality. This commentary focuses primarily on the events and people involved in the cholesterol controversy in Britain. The foremost critics of the lipid hypothesis are now deceased but unfortunately for many of the patients with hypercholesterolaemia and coronary heart disease it took the best part of 50 years to disprove the sceptics. This brief account relates why it took so long.

  20. CHOBIMALT: A Cholesterol-Based Detergent†

    PubMed Central

    Howell, Stanley C.; Mittal, Ritesh; Huang, Lijun; Travis, Benjamin; Breyer, Richard M.; Sanders, Charles R.

    2010-01-01

    Cholesterol and its hemisuccinate and sulfate derivatives are widely used in studies of purified membrane proteins, but are difficult to solubilize in aqueous solution, even in the presence of detergent micelles. Other cholesterol derivatives do not form conventional micelles and lead to viscous solutions. To address these problems a cholesterol-based detergent, CHOBIMALT, has been synthesized and characterized. At concentrations above 3–4μM, CHOBIMALT forms micelles without the need for elevated temperatures or sonic disruption. Diffusion and fluorescence measurements indicated that CHOBIMALT micelles are large (210 ± 30 kDa). The ability to solubilize a functional membrane protein was explored using a G-protein coupled receptor, the human kappa opioid receptor type 1 (hKOR1). While CHOBIMALT alone was not found to be effective as a surfactant for membrane extraction, when added to classical detergent micelles CHOBIMALT was observed to dramatically enhance the thermal stability of solubilized hKOR1. PMID:20919740

  1. Serum cholesterol in healthy postmenopausal women.

    PubMed

    Samanta, B B

    1998-05-01

    Hypercholes erolaemia is a modifiable risk factor in atherosclerosis. Women lose their relative protection against coronory heart disease at menopause because of changed lipid profile due to oestrogen deficiency. Total serum cholesterol was estimated in 82 healthy postmenopausal women in the age group of 46-72 years (51.5 +/- 7.39). Thirty five healthy pre-menopausal women in the age group of 18-38 years (29.5 +/- 6.4) served as controls. The mean serum cholesterol concentration was significantly higher in the postmenopausal group compared to control group (178.5 +/- 39.8 Vs 155.4 +/- 24 mg/dl; P < 0.01). Serum cholesterol concentration in the study group was not related to social class, dietary habit and obesity.

  2. Statins and the cholesterol mortality paradox.

    PubMed

    Nunes, José Pedro L

    2017-02-01

    Large-scale randomised controlled trials, carried out in the context of secondary cardiovascular prevention, have shown that statins are superior to placebo: these drugs were shown to decrease cardiovascular events and total mortality. A further set of clinical trials compared high intensity to low/standard intensity LDL cholesterol lowering in the same setting (using either statins or a statin/ezetimibe association). In this case, a decrease in LDL cholesterol and a concomitant significant reduction in cardiovascular events were seen with intensive therapy, however with no change in total mortality. This phenomenon we may term the LDL cholesterol mortality paradox. It could be due either to the prevention (by high-intensity therapy) of episodes not severe enough to lead to the death of patients, or to high-intensity therapy leading to the death of some patients at the same time as preventing the death of others, with a null aggregate effect. Several types of adverse effects have been seen with statin therapy, such as a possible increased incidence of Diabetes mellitus and of myopathy. The decision to start high-intensity LDL cholesterol lowering (rather than low- or moderate-intensity statin treatment) should be evaluated on a case-by-case basis, taking into consideration the overall aspects of each patient, including the patient's preferences. High-intensity LDL cholesterol lowering, up to the present moment, has failed to produce a change in overall prognosis (total mortality), and should not therefore be mandatory in secondary cardiovascular prevention. It remains to be seen if a similar LDL cholesterol mortality paradox occurs with new drugs targeting plasma lipids.

  3. Tympanomastoid cholesterol granulomas: Immunohistochemical evaluation of angiogenesis.

    PubMed

    Iannella, Giannicola; Di Gioia, Cira; Carletti, Raffaella; Magliulo, Giuseppe

    2017-08-01

    This study investigates the immunohistochemical expression of vascular endothelial growth factor (VEGF) and CD34 in patients treated for middle ear and mastoid cholesterol granulomas to evaluate the angiogenesis and vascularization of this type of lesion. A correlation between the immunohistochemical data and the radiological and intraoperative evidence of temporal bone marrow invasion and blood source connection was performed to validate this hypothesis. Retrospective study. Immunohistochemical expression of VEGF and CD34 in a group of 16 patients surgically treated for cholesterol granuloma was examined. Middle ear cholesteatomas with normal middle ear mucosa and external auditory canal skin were used as the control groups. The radiological and intraoperative features of cholesterol granulomas were also examined. In endothelial cells, there was an increased expression of angiogenetic growth factor receptors in all the cholesterol granulomas in this study. The quantitative analysis of VEGF showed a mean value of 37.5, whereas the CD34 quantitative analysis gave a mean value of 6.8. Seven patients presented radiological or intraoperative evidence of bone marrow invasion, hematopoietic potentialities, or blood source connections that might support the bleeding theory. In all of these cases there was computed tomography or intraoperative evidence of bone erosion of the middle ear and/or temporal bone structures. The mean values of VEGF and CD34 were 41.1 and 7.7, respectively. High values of VEGF and CD34 are present in patients with cholesterol granulomas. Upregulation of VEGF and CD34 is indicative of a remarkable angiogenesis and a widespread vascular concentration in cholesterol granulomas. 3b. Laryngoscope, 127:E283-E290, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  4. Familial hypercholesterolaemia: cholesterol efflux and coronary disease.

    PubMed

    Versmissen, Jorie; Vongpromek, Ranitha; Yahya, Reyhana; van der Net, Jeroen B; van Vark-van der Zee, Leonie; Blommesteijn-Touw, Jeannette; Wattimena, Darcos; Rietveld, Trinet; Pullinger, Clive R; Christoffersen, Christina; Dahlbäck, Björn; Kane, John P; Mulder, Monique; Sijbrands, Eric J G

    2016-07-01

    Coronary heart disease (CHD) risk inversely associates with levels of high-density lipoprotein cholesterol (HDL-C). The protective effect of HDL is thought to depend on its functionality, such as its ability to induce cholesterol efflux. We compared plasma cholesterol efflux capacity between male familial hypercholesterolaemia (FH) patients with and without CHD relative to their non-FH brothers, and examined HDL constituents including sphingosine-1-phosphate (S1P) and its carrier apolipoprotein M (apoM). Seven FH patients were asymptomatic and six had experienced a cardiac event at a mean age of 39 years. Compared to their non-FH brothers, cholesterol efflux from macrophages to plasma from the FH patients without CHD was 16 ± 22% (mean ± SD) higher and to plasma from the FH patients with CHD was 7 ± 8% lower (P = 0·03, CHD vs. non-CHD). Compared to their non-FH brothers, FH patients without CHD displayed significantly higher levels of HDL-cholesterol, HDL-S1P and apoM, while FH patients with CHD displayed lower levels than their non-FH brothers. A higher plasma cholesterol efflux capacity and higher S1P and apoM content of HDL in asymptomatic FH patients may play a role in their apparent protection from premature CHD. © 2016 The Authors. European Journal of Clinical Investigation published by John Wiley & Sons Ltd on behalf of Stichting European Society for Clinical Investigation Journal Foundation.

  5. Aspirin Increases the Solubility of Cholesterol in Lipid Membranes

    NASA Astrophysics Data System (ADS)

    Alsop, Richard; Barrett, Matthew; Zheng, Sonbo; Dies, Hannah; Rheinstadter, Maikel

    2014-03-01

    Aspirin (ASA) is often prescribed for patients with high levels of cholesterol for the secondary prevention of myocardial events, a regimen known as the Low-Dose Aspirin Therapy. We have recently shown that Aspirin partitions in lipid bilayers. However, a direct interplay between ASA and cholesterol has not been investigated. Cholesterol is known to insert itself into the membrane in a dispersed state at moderate concentrations (under ~37.5%) and decrease fluidity of membranes. We prepared model lipid membranes containing varying amounts of both ASA and cholesterol molecules. The structure of the bilayers as a function of ASA and cholesterol concentration was determined using high-resolution X-ray diffraction. At cholesterol levels of more than 40mol%, immiscible cholesterol plaques formed. Adding ASA to the membranes was found to dissolve the cholesterol plaques, leading to a fluid lipid bilayer structure. We present first direct evidence for an interaction between ASA and cholesterol on the level of the cell membrane.

  6. Carbohydrate Loading.

    ERIC Educational Resources Information Center

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  7. Carbohydrate Loading.

    ERIC Educational Resources Information Center

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  8. Cholesterol Mediates Membrane Curvature during Fusion Events

    NASA Astrophysics Data System (ADS)

    Ivankin, Andrey; Kuzmenko, Ivan; Gidalevitz, David

    2012-06-01

    Biomembranes undergo extensive shape changes as they perform vital cellular functions. The mechanisms by which lipids and proteins control membrane curvature remain unclear. We use x-ray reflectivity, grazing incidence x-ray diffraction, and epifluorescence microscopy to study binding of HIV-1 glycoprotein gp41’s membrane-bending domain to DPPC/cholesterol monolayers of various compositions at the air-liquid interface. The results offer a new insight into how membrane curvature could be regulated by cholesterol during fusion of the viral lipid envelope and the host cell membranes.

  9. [Basic mechanisms: absorption and excretion of cholesterol and other sterols].

    PubMed

    Cofan Pujol, Montserrat

    2014-01-01

    Cholesterol is of vital importance for vertebrate cell membrane structure and function. It is obvious that adequate regulation of cholesterol homeostasis is essential. Hypercholesterolemia promotes atherosclerosis and thereby represents a major risk factor for cardiovascular disease. The liver has been considered the major site of control in maintenance of cholesterol homeostasis. The liver facilitates clearance of (very) low density lipoprotein particles and cholesterol-containing chylomicron remnants, synthesizes cholesterol, synthesizes and secretes (nascent) high density lipoprotein particles, secretes cholesterol and bile salts to bile, and is involved in reverse cholesterol transport. In recent years, however, the importance of the intestine in many aspects of cholesterol physiology is increasingly recognized. It has become apparent that direct secretion of cholesterol from the blood compartment into the intestine, or transintestinal cholesterol excretion, plays a major role in disposal of cholesterol via the feces. This review will discuss current knowledge on the physiology of cholesterol homeostasis, with emphasis on cholesterol absorption, cholesterol synthesis and fecal excretion, and therapeutic options for hypercholesterolemia. Copyright © 2013 Elsevier España, S.L. y SEA. All rights reserved.

  10. Free cholesterol accumulation in liver sinusoidal endothelial cells exacerbates acetaminophen hepatotoxicity via TLR9 signaling.

    PubMed

    Teratani, Toshiaki; Tomita, Kengo; Suzuki, Takahiro; Furuhashi, Hirotaka; Irie, Rie; Hida, Shigeaki; Okada, Yoshikiyo; Kurihara, Chie; Ebinuma, Hirotoshi; Nakamoto, Nobuhiro; Saito, Hidetsugu; Hibi, Toshifumi; Miura, Soichiro; Hokari, Ryota; Kanai, Takanori

    2017-10-01

    Although obesity is a risk factor for acute liver failure, the pathogenic mechanisms are not yet fully understood. High cholesterol (HC) intake, which often underlies obesity, is suggested to play a role in the mechanism. We aimed to elucidate the effect of a HC diet on acetaminophen-induced acute liver injury, the most frequent cause of acute liver failure in the USA. C57BL/6 Toll-like receptor 9 (TLR9) knockout (Tlr9(-/-)) mice and their Tlr9(+/+) littermates were fed an HC diet for fourweeks and then treated with acetaminophen. Liver sinusoidal endothelial cells (LSECs) were isolated from the mice for in vivo and in vitro analyses. The HC diet exacerbated acetaminophen-induced acute liver injury in a TLR9/inflammasome pathway-dependent manner. LSECs played a major role in the cholesterol loading-induced exacerbation. The accumulation of free cholesterol in the endolysosomes in LSECs enhanced TLR9-mediated signaling, thereby exacerbating the pathology of acetaminophen-induced liver injury through the activation of the TLR9/inflammasome pathway. The accumulation of free cholesterol in LSEC endolysosomes induced a dysfunction of the Rab7 membrane trafficking recycling mechanism, thus disrupting the transport of TLR9 from late endosomes to the lysosomes. Consequently, the level of active TLR9 in the late endosomes increased, thereby enhancing TLR9 signaling in LSECs. HC intake exaggerated acetaminophen-induced acute liver injury via free cholesterol accumulation in LSECs, demonstrating a novel role of free cholesterol as a metabolic factor in TLR9 signal regulation and pathologies of acetaminophen-induced liver injury. Therapeutic approaches may target this pathway. Lay summary: High cholesterol intake exacerbated acetaminophen-induced acute liver injury via the accumulation of free cholesterol in the endolysosomes of liver sinusoidal endothelial cells. This accumulation enhanced Toll-like receptor 9 signaling via impairment of its membrane trafficking mechanism

  11. Phospholipid transfer protein deficiency in mice impairs macrophage reverse cholesterol transport in vivo.

    PubMed

    Si, Yanhong; Zhang, Ying; Chen, Xiaofeng; Zhai, Lei; Zhou, Guanghai; Yu, Ailing; Cao, Haijun; Shucun, Qin

    2016-07-01

    Phospholipid transfer protein is expressed in various cell types and secreted into plasma, where it transfers phospholipids between lipoproteins and modulates the composition of high-density lipoprotein particles. Phospholipid transfer protein deficiency in vivo can lower high-density lipoprotein cholesterol level significantly and impact the biological quality of high-density lipoprotein. Considering high-density lipoprotein was a critical determinant for reverse cholesterol transport, we investigated the role of systemic phospholipid transfer protein deficiency in macrophage reverse cholesterol transport in vivo After the littermate phospholipid transfer protein KO and WT mice were fed high-fat diet for one month, they were injected intraperitoneally with (3)H-cholesterol-labeled and acLDL-loaded macrophages. Then the appearance of (3)H-tracer in plasma, liver, bile, intestinal wall, and feces over 48 h was determined. Plasma lipid analysis indicated phospholipid transfer protein deficiency lowered total cholesterol, high-density lipoprotein-C and apolipoprotein A1 levels significantly but increased triglyceride level in mice. The isotope tracing experiment showed (3)H-cholesterol of plasma was decreased by 68% for male and 62% for female, and (3)H-tracer of bile was decreased by 37% for male and 21% for female in phospholipid transfer protein KO mice compared with WT mice. However, there was no difference in liver, and (3)H-tracer of intestinal wall was increased by 43% for male and 27% for female. Finally, (3)H-tracer of fecal excretion in phospholipid transfer protein KO mice was reduced significantly by 36% for male and 43% for female during 0-24 h period, but there was no significant difference during 24-48 h period. Meanwhile, Western Blot analysis showed the expressions of reverse cholesterol transport -related protein liver X receptor α (LXRα), ATP binding cassette transporter A1, and cholesterol 7α-hydroxylase A1 were upregulated in liver of

  12. Phospholipid transfer protein deficiency in mice impairs macrophage reverse cholesterol transport in vivo

    PubMed Central

    Si, Yanhong; Zhang, Ying; Chen, Xiaofeng; Zhai, Lei; Zhou, Guanghai; Yu, Ailing; Cao, Haijun

    2016-01-01

    Phospholipid transfer protein is expressed in various cell types and secreted into plasma, where it transfers phospholipids between lipoproteins and modulates the composition of high-density lipoprotein particles. Phospholipid transfer protein deficiency in vivo can lower high-density lipoprotein cholesterol level significantly and impact the biological quality of high-density lipoprotein. Considering high-density lipoprotein was a critical determinant for reverse cholesterol transport, we investigated the role of systemic phospholipid transfer protein deficiency in macrophage reverse cholesterol transport in vivo. After the littermate phospholipid transfer protein KO and WT mice were fed high-fat diet for one month, they were injected intraperitoneally with 3H-cholesterol-labeled and acLDL-loaded macrophages. Then the appearance of 3H-tracer in plasma, liver, bile, intestinal wall, and feces over 48 h was determined. Plasma lipid analysis indicated phospholipid transfer protein deficiency lowered total cholesterol, high-density lipoprotein-C and apolipoprotein A1 levels significantly but increased triglyceride level in mice. The isotope tracing experiment showed 3H-cholesterol of plasma was decreased by 68% for male and 62% for female, and 3H-tracer of bile was decreased by 37% for male and 21% for female in phospholipid transfer protein KO mice compared with WT mice. However, there was no difference in liver, and 3H-tracer of intestinal wall was increased by 43% for male and 27% for female. Finally, 3H-tracer of fecal excretion in phospholipid transfer protein KO mice was reduced significantly by 36% for male and 43% for female during 0–24 h period, but there was no significant difference during 24–48 h period. Meanwhile, Western Blot analysis showed the expressions of reverse cholesterol transport -related protein liver X receptor α (LXRα), ATP binding cassette transporter A1, and cholesterol 7α-hydroxylase A1 were upregulated in liver of

  13. Genetic Evidence Implicates the Immune System and Cholesterol Metabolism in the Aetiology of Alzheimer's Disease

    PubMed Central

    Hamshere, Marian L.; Harold, Denise; Moskvina, Valentina; Ivanov, Dobril; Pocklington, Andrew; Abraham, Richard; Hollingworth, Paul; Sims, Rebecca; Gerrish, Amy; Pahwa, Jaspreet Singh; Jones, Nicola; Stretton, Alexandra; Morgan, Angharad R.; Lovestone, Simon; Powell, John; Proitsi, Petroula; Lupton, Michelle K.; Brayne, Carol; Rubinsztein, David C.; Gill, Michael; Lawlor, Brian; Lynch, Aoibhinn; Morgan, Kevin; Brown, Kristelle S.; Passmore, Peter A.; Craig, David; McGuinness, Bernadette; Todd, Stephen; Holmes, Clive; Mann, David; Smith, A. David; Love, Seth; Kehoe, Patrick G.; Mead, Simon; Fox, Nick; Rossor, Martin; Collinge, John; Maier, Wolfgang; Jessen, Frank; Schürmann, Britta; van den Bussche, Hendrik; Heuser, Isabella; Peters, Oliver; Kornhuber, Johannes; Wiltfang, Jens; Dichgans, Martin; Frölich, Lutz; Hampel, Harald; Hüll, Michael; Rujescu, Dan; Goate, Alison M.; Kauwe, John S. K.; Cruchaga, Carlos; Nowotny, Petra; Morris, John C.; Mayo, Kevin; Livingston, Gill; Bass, Nicholas J.; Gurling, Hugh; McQuillin, Andrew; Gwilliam, Rhian; Deloukas, Panos; Al-Chalabi, Ammar; Shaw, Christopher E.; Singleton, Andrew B.; Guerreiro, Rita; Mühleisen, Thomas W.; Nöthen, Markus M.; Moebus, Susanne; Jöckel, Karl-Heinz; Klopp, Norman; Wichmann, H.-Erich; Rüther, Eckhard; Carrasquillo, Minerva M.; Pankratz, V. Shane; Younkin, Steven G.; Hardy, John; O'Donovan, Michael C.; Owen, Michael J.; Williams, Julie

    2010-01-01

    Background Late Onset Alzheimer's disease (LOAD) is the leading cause of dementia. Recent large genome-wide association studies (GWAS) identified the first strongly supported LOAD susceptibility genes since the discovery of the involvement of APOE in the early 1990s. We have now exploited these GWAS datasets to uncover key LOAD pathophysiological processes. Methodology We applied a recently developed tool for mining GWAS data for biologically meaningful information to a LOAD GWAS dataset. The principal findings were then tested in an independent GWAS dataset. Principal Findings We found a significant overrepresentation of association signals in pathways related to cholesterol metabolism and the immune response in both of the two largest genome-wide association studies for LOAD. Significance Processes related to cholesterol metabolism and the innate immune response have previously been implicated by pathological and epidemiological studies of Alzheimer's disease, but it has been unclear whether those findings reflected primary aetiological events or consequences of the disease process. Our independent evidence from two large studies now demonstrates that these processes are aetiologically relevant, and suggests that they may be suitable targets for novel and existing therapeutic approaches. PMID:21085570

  14. Serum cholesterol and variant in cholesterol-related gene CETP predict white matter microstructure.

    PubMed

    Warstadt, Nicholus M; Dennis, Emily L; Jahanshad, Neda; Kohannim, Omid; Nir, Talia M; McMahon, Katie L; de Zubicaray, Greig I; Montgomery, Grant W; Henders, Anjali K; Martin, Nicholas G; Whitfield, John B; Jack, Clifford R; Bernstein, Matt A; Weiner, Michael W; Toga, Arthur W; Wright, Margaret J; Thompson, Paul M

    2014-11-01

    Several common genetic variants influence cholesterol levels, which play a key role in overall health. Myelin synthesis and maintenance are highly sensitive to cholesterol concentrations, and abnormal cholesterol levels increase the risk for various brain diseases, including Alzheimer's disease. We report significant associations between higher serum cholesterol (CHOL) and high-density lipoprotein levels and higher fractional anisotropy in 403 young adults (23.8 ± 2.4 years) scanned with diffusion imaging and anatomic magnetic resonance imaging at 4 Tesla. By fitting a multi-locus genetic model within white matter areas associated with CHOL, we found that a set of 18 cholesterol-related, single-nucleotide polymorphisms implicated in Alzheimer's disease risk predicted fractional anisotropy. We focused on the single-nucleotide polymorphism with the largest individual effects, CETP (rs5882), and found that increased G-allele dosage was associated with higher fractional anisotropy and lower radial and mean diffusivities in voxel-wise analyses of the whole brain. A follow-up analysis detected white matter associations with rs5882 in the opposite direction in 78 older individuals (74.3 ± 7.3 years). Cholesterol levels may influence white matter integrity, and cholesterol-related genes may exert age-dependent effects on the brain.

  15. Effects of pravastatin on cholesterol metabolism of cholesterol-fed heterozygous WHHL rabbits

    PubMed Central

    Harsch, Michael; Gebhardt, Angelika; Reymann, Andreas; Lang, Gerhard; Schliack, Michael; Löser, Roland; Hinrich Braesen, Jan; Niendorf, Axel

    1998-01-01

    We administered the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor pravastatin at a daily dose of 1 mg kg−1 body weight to cholesterol-fed (0.03%) heterozygous Watanabe heritable hyperlipidaemic rabbits, an animal model for heterozygous familial hypercholesterolaemia.After 12 months of cholesterol treatment, immunohistochemistry with the monoclonal antibody 9D9 was used to detect hepatic low density lipoprotein (LDL) receptors, which were quantified by densitometry. In addition we determined LDL receptor mRNA by competitive reverse transcriptase polymerase chain reaction. The cholesterol precursor lathosterol and the plant sterol campesterol were analysed by gas-liquid chromatography.The drug reduced total plasma cholesterol levels by 51% (P=0.04), when compared to the control group. Unexpectedly, hepatic LDL receptor density and mRNA showed no significant differences between the groups. Total plasma levels of lathosterol and campesterol also revealed no significant differences between the groups, if expressed relative to plasma cholesterol.The findings suggest that mechanisms other than induced hepatic LDL receptors are responsible for the cholesterol-lowering effect of pravastatin in this animal model. We propose a reduced cholesterol absorption efficiency compatible with similar campesterol levels between both groups observed in our study. PMID:9641543

  16. Intracellular cholesterol transporter StarD4 binds free cholesterol and increases cholesteryl ester formation*

    PubMed Central

    Rodriguez-Agudo, Daniel; Ren, Shunlin; Wong, Eric; Marques, Dalila; Redford, Kaye; Gil, Gregorio; Hylemon, Phillip; Pandak, William M.

    2008-01-01

    StarD4 protein is a member of the StarD4 subfamily of steroidogenic acute regulatory-related lipid transfer (START) domain proteins that includes StarD5 and StarD6, proteins whose functions remain poorly defined. The objective of this study was to isolate and characterize StarD4's sterol binding and to determine in a hepatocyte culture model its sterol transport capabilities. Utilizing purified full-length StarD4, in vitro binding assays demonstrated a concentration-dependent binding of [14C]cholesterol by StarD4 similar to that of the cholesterol binding START domain proteins StarD1 and StarD5. Other tested sterols showed no detectable binding to StarD4, except for 7α-hydroxycholesterol, for which StarD4 demonstrated weak binding on lipid protein overlay assays. Subsequently, an isolated mouse hepatocyte model was used to study the ability of StarD4 to bind/mobilize/distribute cellular cholesterol. Increased expression of StarD4 in primary mouse hepatocytes led to a marked increase in the intracellular cholesteryl ester concentration and in the rates of bile acid synthesis. The ability and specificity of StarD4 to bind cholesterol and, as a function of its level of expression, to direct endogenous cellular cholesterol suggest that StarD4 plays an important role as a directional cholesterol transporter in the maintenance of cellular cholesterol homeostasis. PMID:18403318

  17. Lysosomal membrane glycoproteins bind cholesterol and contribute to lysosomal cholesterol export

    PubMed Central

    Li, Jian; Pfeffer, Suzanne R

    2016-01-01

    LAMP1 and LAMP2 proteins are highly abundant, ubiquitous, mammalian proteins that line the lysosome limiting membrane, and protect it from lysosomal hydrolase action. LAMP2 deficiency causes Danon’s disease, an X-linked hypertrophic cardiomyopathy. LAMP2 is needed for chaperone-mediated autophagy, and its expression improves tissue function in models of aging. We show here that human LAMP1 and LAMP2 bind cholesterol in a manner that buries the cholesterol 3β-hydroxyl group; they also bind tightly to NPC1 and NPC2 proteins that export cholesterol from lysosomes. Quantitation of cellular LAMP2 and NPC1 protein levels suggest that LAMP proteins represent a significant cholesterol binding site at the lysosome limiting membrane, and may signal cholesterol availability. Functional rescue experiments show that the ability of human LAMP2 to facilitate cholesterol export from lysosomes relies on its ability to bind cholesterol directly. DOI: http://dx.doi.org/10.7554/eLife.21635.001 PMID:27664420

  18. Inhibiting Cholesterol Absorption During Lactation Programs Future Intestinal Absorption of Cholesterol in Adult Mice.

    PubMed

    Dimova, Lidiya G; de Boer, Jan Freark; Plantinga, Josee; Plösch, Torsten; Hoekstra, Menno; Verkade, Henkjan J; Tietge, Uwe J F

    2017-08-01

    In nematodes, the intestine senses and integrates early life dietary cues that lead to lifelong epigenetic adaptations to a perceived nutritional environment-it is not clear whether this process occurs in mammals. We aimed to establish a mouse model of reduced dietary cholesterol availability from maternal milk and investigate the consequences of decreased milk cholesterol availability, early in life, on the metabolism of cholesterol in adult mice. We blocked intestinal absorption of cholesterol in milk fed to newborn mice by supplementing the food of dams (for 3 weeks between birth and weaning) with ezetimibe, which is secreted into milk. Ezetimibe interacts with the intestinal cholesterol absorption transporter NPC1l1 to block cholesterol uptake into enterocytes. Characterization of these offspring at 24 weeks of age showed a 27% decrease in cholesterol absorption (P < .001) and reduced levels of Npc1l1 messenger RNA and protein, but not other cholesterol transporters, in the proximal small intestine. We observed increased histone H3K9me3 methylation at positions -423 to -607 of the proximal Npc1l1 promoter in small intestine tissues from 24-week-old offspring fed ezetimibe during lactation, compared with controls. These findings show that the early postnatal mammalian intestine functions as an environmental sensor of nutritional conditions, responding to conditions such as low cholesterol levels by epigenetic modifications of genes. Further studies are needed to determine how decreased sterol absorption for a defined period might activate epigenetic regulators; the findings of our study might have implications for human infant nutrition and understanding and preventing cardiometabolic disease. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

  19. An amperometric cholesterol biosensor based on epoxy resin membrane bound cholesterol oxidase

    PubMed Central

    Pundir, C.S.; Narang, Jagriti; Chauhan, Nidhi; Sharma, Preety; Sharma, Renu

    2012-01-01

    Background & objectives: The use of epoxy resin membrane as a support for immobilization of enzyme has resulted into improved sensitivity and stability of biosensors for uric acid, ascorbic acid and polyphenols. The present work was aimed to prepare an improved amperometric biosensor for determination of serum cholesterol required in the diagnostics and management of certain pathological conditions. Methods: Epoxy resin membrane with immobilized cholesterol oxidase was mounted on the cleaned platinum (Pt) electrode with a parafilm to construct a working electrode. This working electrode along with Ag/AgCl as reference and Ag wire as an auxiliary electrode were connected through a three terminal electrometer to construct a cholesterol biosensor. Results: The sensor showed optimum response within 25 sec at pH 7.0 and 45°C. The linear working range of biosensor was 1.0 to 8.0 mM cholesterol. Km and Imax for cholesterol were 5.0 mM and 9.09 μA, respectively. The biosensor measured serum cholesterol. The minimum detection limit of the sensor was 1.0 mM. The mean analytical recoveries of added cholesterol in serum (2.84 and 4.13 mM) were 91.4±2.8 and 92.3±3.1 per cent (n=6), respectively. Within and between assay coefficient of variation (CV) were <2 and <4 per cent, respectively. Biosensor had a storage life of 6 months at 4°C. Interpretation & conclusions: The use of epoxy resin membrane as a support for immobilization of cholesterol oxidase has resulted into an improved amperometric cholesterol biosensor. The present biosensor had an advantage over the existing biosensors as it worked at comparatively lower potential. PMID:23168704

  20. An amperometric cholesterol biosensor based on epoxy resin membrane bound cholesterol oxidase.

    PubMed

    Pundir, C S; Narang, Jagriti; Chauhan, Nidhi; Sharma, Preety; Sharma, Renu

    2012-10-01

    The use of epoxy resin membrane as a support for immobilization of enzyme has resulted into improved sensitivity and stability of biosensors for uric acid, ascorbic acid and polyphenols. The present work was aimed to prepare an improved amperometric biosensor for determination of serum cholesterol required in the diagnostics and management of certain pathological conditions. Epoxy resin membrane with immobilized cholesterol oxidase was mounted on the cleaned platinum (Pt) electrode with a parafilm to construct a working electrode. This working electrode along with Ag/AgCl as reference and Ag wire as an auxiliary electrode were connected through a three terminal electrometer to construct a cholesterol biosensor. The sensor showed optimum response within 25 sec at pH 7.0 and 45°C. The linear working range of biosensor was 1.0 to 8.0 mM cholesterol. K m and I max for cholesterol were 5.0 mM and 9.09 μA, respectively. The biosensor measured serum cholesterol. The minimum detection limit of the sensor was 1.0 mM. The mean analytical recoveries of added cholesterol in serum (2.84 and 4.13 mM) were 91.4 ± 2.8 and 92.3 ± 3.1 per cent (n=6), respectively. Within and between assay coefficient of variation (CV) were <2 and <4 per cent, respectively. Biosensor had a storage life of 6 months at 4 o C. The use of epoxy resin membrane as a support for immobilization of cholesterol oxidase has resulted into an improved amperometric cholesterol biosensor. The present biosensor had an advantage over the existing biosensors as it worked at comparatively lower potential.

  1. Intestinal SR-BI does not impact cholesterol absorption or transintestinal cholesterol efflux in mice.

    PubMed

    Bura, Kanwardeep S; Lord, Caleb; Marshall, Stephanie; McDaniel, Allison; Thomas, Gwyn; Warrier, Manya; Zhang, Jun; Davis, Matthew A; Sawyer, Janet K; Shah, Ramesh; Wilson, Martha D; Dikkers, Arne; Tietge, Uwe J F; Collet, Xavier; Rudel, Lawrence L; Temel, Ryan E; Brown, J Mark

    2013-06-01

    Reverse cholesterol transport (RCT) can proceed through the classic hepatobiliary route or through the nonbiliary transintestinal cholesterol efflux (TICE) pathway. Scavenger receptor class B type I (SR-BI) plays a critical role in the classic hepatobiliary route of RCT. However, the role of SR-BI in TICE has not been studied. To examine the role of intestinal SR-BI in TICE, sterol balance was measured in control mice and mice transgenically overexpressing SR-BI in the proximal small intestine (SR-BI(hApoCIII-ApoAIV-Tg)). SR-BI(hApoCIII-ApoAIV-Tg) mice had significantly lower plasma cholesterol levels compared with wild-type controls, yet SR-BI(hApoCIII-ApoAIV-Tg) mice had normal fractional cholesterol absorption and fecal neutral sterol excretion. Both in the absence or presence of ezetimibe, intestinal SR-BI overexpression had no impact on the amount of cholesterol excreted in the feces. To specifically study effects of intestinal SR-BI on TICE we crossed SR-BI(hApoCIII-ApoAIV-Tg) mice into a mouse model that preferentially utilized the TICE pathway for RCT (Niemann-Pick C1-like 1 liver transgenic), and likewise found no alterations in cholesterol absorption or fecal sterol excretion. Finally, mice lacking SR-BI in all tissues also exhibited normal cholesterol absorption and fecal cholesterol disposal. Collectively, these results suggest that SR-BI is not rate limiting for intestinal cholesterol absorption or for fecal neutral sterol loss through the TICE pathway.

  2. Cholesterol homeostasis: How do cells sense sterol excess?

    PubMed

    Howe, Vicky; Sharpe, Laura J; Alexopoulos, Stephanie J; Kunze, Sarah V; Chua, Ngee Kiat; Li, Dianfan; Brown, Andrew J

    2016-09-01

    Cholesterol is vital in mammals, but toxic in excess. Consequently, elaborate molecular mechanisms have evolved to maintain this sterol within narrow limits. How cells sense excess cholesterol is an intriguing area of research. Cells sense cholesterol, and other related sterols such as oxysterols or cholesterol synthesis intermediates, and respond to changing levels through several elegant mechanisms of feedback regulation. Cholesterol sensing involves both direct binding of sterols to the homeostatic machinery located in the endoplasmic reticulum (ER), and indirect effects elicited by sterol-dependent alteration of the physical properties of membranes. Here, we examine the mechanisms employed by cells to maintain cholesterol homeostasis.

  3. Impaired HDL2-mediated cholesterol efflux is associated with metabolic syndrome in families with early onset coronary heart disease and low HDL-cholesterol level.

    PubMed

    Paavola, Timo; Kuusisto, Sanna; Jauhiainen, Matti; Kakko, Sakari; Kangas-Kontio, Tiia; Metso, Jari; Soininen, Pasi; Ala-Korpela, Mika; Bloigu, Risto; Hannuksela, Minna L; Savolainen, Markku J; Salonurmi, Tuire

    2017-01-01

    The potential of high-density lipoproteins (HDL) to facilitate cholesterol removal from arterial foam cells is a key function of HDL. We studied whether cholesterol efflux to serum and HDL subfractions is impaired in subjects with early coronary heart disease (CHD) or metabolic syndrome (MetS) in families where a low HDL-cholesterol level (HDL-C) predisposes to early CHD. HDL subfractions were isolated from plasma by sequential ultracentrifugation. THP-1 macrophages loaded with acetyl-LDL were used in the assay of cholesterol efflux to total HDL, HDL2, HDL3 or serum. While cholesterol efflux to serum, total HDL and HDL3 was unchanged, the efflux to HDL2 was 14% lower in subjects with MetS than in subjects without MetS (p<0.001). The efflux to HDL2 was associated with components of MetS such as plasma HDL-C (r = 0.76 in men and r = 0.56 in women, p<0.001 for both). The efflux to HDL2 was reduced in men with early CHD (p<0.01) only in conjunction with their low HDL-C. The phospholipid content of HDL2 particles was a major correlate with the efflux to HDL2 (r = 0.70, p<0.001). A low ratio of HDL2 to total HDL was associated with MetS (p<0.001). Our results indicate that impaired efflux to HDL2 is a functional feature of the low HDL-C state and MetS in families where these risk factors predispose to early CHD. The efflux to HDL2 related to the phospholipid content of HDL2 particles but the phospholipid content did not account for the impaired efflux in cardiometabolic disease, where a combination of low level and poor quality of HDL2 was observed.

  4. Impaired HDL2-mediated cholesterol efflux is associated with metabolic syndrome in families with early onset coronary heart disease and low HDL-cholesterol level

    PubMed Central

    Paavola, Timo; Kuusisto, Sanna; Jauhiainen, Matti; Kakko, Sakari; Kangas-Kontio, Tiia; Metso, Jari; Soininen, Pasi; Ala-Korpela, Mika; Bloigu, Risto; Hannuksela, Minna L.; Savolainen, Markku J.

    2017-01-01

    Objective The potential of high-density lipoproteins (HDL) to facilitate cholesterol removal from arterial foam cells is a key function of HDL. We studied whether cholesterol efflux to serum and HDL subfractions is impaired in subjects with early coronary heart disease (CHD) or metabolic syndrome (MetS) in families where a low HDL-cholesterol level (HDL-C) predisposes to early CHD. Methods HDL subfractions were isolated from plasma by sequential ultracentrifugation. THP-1 macrophages loaded with acetyl-LDL were used in the assay of cholesterol efflux to total HDL, HDL2, HDL3 or serum. Results While cholesterol efflux to serum, total HDL and HDL3 was unchanged, the efflux to HDL2 was 14% lower in subjects with MetS than in subjects without MetS (p<0.001). The efflux to HDL2 was associated with components of MetS such as plasma HDL-C (r = 0.76 in men and r = 0.56 in women, p<0.001 for both). The efflux to HDL2 was reduced in men with early CHD (p<0.01) only in conjunction with their low HDL-C. The phospholipid content of HDL2 particles was a major correlate with the efflux to HDL2 (r = 0.70, p<0.001). A low ratio of HDL2 to total HDL was associated with MetS (p<0.001). Conclusion Our results indicate that impaired efflux to HDL2 is a functional feature of the low HDL-C state and MetS in families where these risk factors predispose to early CHD. The efflux to HDL2 related to the phospholipid content of HDL2 particles but the phospholipid content did not account for the impaired efflux in cardiometabolic disease, where a combination of low level and poor quality of HDL2 was observed. PMID:28207870

  5. HDL-apolipoprotein A-I exchange is independently associated with cholesterol efflux capacity.

    PubMed

    Borja, Mark S; Ng, Kit F; Irwin, Angela; Hong, Jaekyoung; Wu, Xing; Isquith, Daniel; Zhao, Xue-Qiao; Prazen, Bryan; Gildengorin, Virginia; Oda, Michael N; Vaisar, Tomáš

    2015-10-01

    HDL is the primary mediator of cholesterol mobilization from the periphery to the liver via reverse cholesterol transport (RCT). A critical first step in this process is the uptake of cholesterol from lipid-loaded macrophages by HDL, a function of HDL inversely associated with prevalent and incident cardiovascular disease. We hypothesized that the dynamic ability of HDL to undergo remodeling and exchange of apoA-I is an important and potentially rate-limiting aspect of RCT. In this study, we investigated the relationship between HDL-apoA-I exchange (HAE) and serum HDL cholesterol (HDL-C) efflux capacity. We compared HAE to the total and ABCA1-specific cholesterol efflux capacity of 77 subjects. We found that HAE was highly correlated with both total (r = 0.69, P < 0.0001) and ABCA1-specific (r = 0.47, P < 0.0001) efflux, and this relationship remained significant after adjustment for HDL-C or apoA-I. Multivariate models of sterol efflux capacity indicated that HAE accounted for approximately 25% of the model variance for both total and ABCA1-specific efflux. We conclude that the ability of HDL to exchange apoA-I and remodel, as measured by HAE, is a significant contributor to serum HDL efflux capacity, independent of HDL-C and apoA-I, indicating that HDL dynamics are an important factor in cholesterol efflux capacity and likely RCT. Copyright © 2015 by the American Society for Biochemistry and Molecular Biology, Inc.

  6. Unexpected inhibition of cholesterol 7 alpha-hydroxylase by cholesterol in New Zealand white and Watanabe heritable hyperlipidemic rabbits.

    PubMed Central

    Xu, G; Salen, G; Shefer, S; Ness, G C; Nguyen, L B; Parker, T S; Chen, T S; Zhao, Z; Donnelly, T M; Tint, G S

    1995-01-01

    We investigated the effect of cholesterol feeding on plasma cholesterol concentrations, hepatic activities and mRNA levels of HMG-CoA reductase and cholesterol 7 alpha-hydroxylase and hepatic LDL receptor function and mRNA levels in 23 New Zealand White (NZW) and 17 Watanabe heritable hyperlipidemic (WHHL) rabbits. Plasma cholesterol concentrations were 9.9 times greater in WHHL than NZW rabbits and rose significantly in both groups when cholesterol was fed. Baseline liver cholesterol levels were 50% higher but rose only 26% in WHHL as compared with 3.6-fold increase with the cholesterol diet in NZW rabbits. In both rabbit groups, hepatic total HMG-CoA reductase activity was similar and declined > 60% without changing enzyme mRNA levels after cholesterol was fed. In NZW rabbits, cholesterol feeding inhibited LDL receptor function but not mRNA levels. As expected, receptor-mediated LDL binding was reduced in WHHL rabbits. Hepatic cholesterol 7 alpha-hydroxylase activity and mRNA levels were 2.8 and 10.4 times greater in NZW than WHHL rabbits. Unexpectedly, cholesterol 7 alpha-hydroxylase activity was reduced 53% and mRNA levels were reduced 79% in NZW rabbits with 2% cholesterol feeding. These results demonstrate that WHHL as compared with NZW rabbits have markedly elevated plasma and higher liver cholesterol concentrations, less hepatic LDL receptor function, and very low hepatic cholesterol 7 alpha-hydroxylase activity and mRNA levels. Feeding cholesterol to NZW rabbits increased plasma and hepatic concentrations greatly, inhibited LDL receptor-mediated binding, and unexpectedly suppressed cholesterol 7 alpha-hydroxylase activity and mRNA to minimum levels similar to WHHL rabbits. Dietary cholesterol accumulates in the plasma of NZW rabbits, and WHHL rabbits are hypercholesterolemic because reduced LDL receptor function is combined with decreased catabolism of cholesterol to bile acids. Images PMID:7706454

  7. Effect of dietary cholesterol and plant sterol consumption on plasma lipid responsiveness and cholesterol trafficking in healthy individuals.

    PubMed

    Alphonse, Peter A S; Ramprasath, Vanu; Jones, Peter J H

    2017-01-01

    Dietary cholesterol and plant sterols differentially modulate cholesterol kinetics and circulating cholesterol. Understanding how healthy individuals with their inherent variabilities in cholesterol trafficking respond to such dietary sterols will aid in improving strategies for effective cholesterol lowering and alleviation of CVD risk. The objectives of this study were to assess plasma lipid responsiveness to dietary cholesterol v. plant sterol consumption, and to determine the response in rates of cholesterol absorption and synthesis to each sterol using stable isotope approaches in healthy individuals. A randomised, double-blinded, crossover, placebo-controlled clinical trial (n 49) with three treatment phases of 4-week duration were conducted in a Manitoba Hutterite population. During each phase, participants consumed one of the three treatments as a milkshake containing 600 mg/d dietary cholesterol, 2 g/d plant sterols or a control after breakfast meal. Plasma lipid profile was determined and cholesterol absorption and synthesis were measured by oral administration of [3, 4-13C] cholesterol and 2H-labelled water, respectively. Dietary cholesterol consumption increased total (0·16 (sem 0·06) mmol/l, P=0·0179) and HDL-cholesterol (0·08 (sem 0·03) mmol/l, P=0·0216) concentrations with no changes in cholesterol absorption or synthesis. Plant sterol consumption failed to reduce LDL-cholesterol concentrations despite showing a reduction (6 %, P=0·0004) in cholesterol absorption. An over-compensatory reciprocal increase in cholesterol synthesis (36 %, P=0·0026) corresponding to a small reduction in absorption was observed with plant sterol consumption, possibly resulting in reduced LDL-cholesterol lowering efficacy of plant sterols. These data suggest that inter-individual variability in cholesterol trafficking mechanisms may profoundly impact plasma lipid responses to dietary sterols in healthy individuals.

  8. Regulation of biliary cholesterol secretion. Functional relationship between the canalicular and sinusoidal cholesterol secretory pathways in the rat.

    PubMed Central

    Nervi, F; Marinović, I; Rigotti, A; Ulloa, N

    1988-01-01

    The functional interrelationship between biliary cholesterol secretion, sinusoidal lipoprotein cholesterol secretion and bile salt synthesis was studied in the rat. Diosgenin, fructose, and colestipol in the diet were used to, respectively, influence biliary cholesterol output, VLDL production and bile salt synthesis. In the acute bile fistula rat, biliary cholesterol output was 700% increased by diosgenin and 50% decreased by fructose. In the rats fed both diosgenin and fructose, biliary cholesterol secretion was increased only by approximately 200%, whereas biliary bile salts and phospholipid outputs were unchanged. In the isolated perfused liver, VLDL-cholesterol output was 50% reduced by diosgenin alone, but was unchanged following feeding of diosgenin plus fructose. However, the livers of rats fed diosgenin plus fructose exhibited a 700% increase in VLDL-triglyceride production and a 200% increase in VLDL-cholesterol output. A significant reciprocal relationship between VLDL-cholesterol secretion and the coupling ratio of cholesterol to bile salts in bile was observed. Colestipol added to the diet maintained both sinusoidal and biliary cholesterol outputs within the normal range. In the chronic bile fistula rat, colestipol increased bile salt synthesis by 100% while diosgenin and fructose diets had no effect. Similarly, the addition of fructose to the colestipol diet did not decrease bile salt synthesis. These data suggest a reciprocal relationship between biliary cholesterol secretion and hepatic secretion of cholesterol as VLDL particles. The free cholesterol pool used for bile salt synthesis seems functionally unrelated to the pool from which VLDL-cholesterol and biliary cholesterol originate. These findings support the idea that metabolic compartmentalization of hepatic cholesterol is a major determinant of the quantity of cholesterol available for recruitment by the bile salt-dependent biliary cholesterol secretory mechanism. PMID:3198756

  9. miRNA Modulation of Cholesterol Homeostasis

    PubMed Central

    Fernández-Hernando, Carlos; Moore, Kathryn J.

    2012-01-01

    Although the roles of the SREBP1 and SREBP2 transcription factors in regulating fatty acid and cholesterol synthesis and uptake have been known for some time, it was recently discovered that two related microRNAs, miR-33a and miR-33b, are embedded in these genes. Studies indicate that miR-33a and miR-33b act with their host genes, Srebp2 and Srebp1, respectively, to reciprocally regulate cholesterol homeostasis and fatty acid metabolism in a negative feedback loop. miR-33 has been shown to post-transcriptionally repress key genes involved in cellular cholesterol export and HDL metabolism (Abca1, Abcg1, Npc1), fatty acid oxidation (Crot, Cpt1a, Hadhb, Ampk), and glucose metabolism (Sirt6, Irs2). Delivery of inhibitors of miR-33 in vitro and in vivo relieves repression of these genes resulting in up-regulation of the associated metabolic pathways. In mouse models, miR-33 antagonism has proven has proven to be an effective strategy for increasing plasma HDL cholesterol and fatty acid oxidation, and protecting from atherosclerosis. These exciting findings have opened up promising new avenues for the development of therapeutics to treat dyslipidemia and other metabolic disorders. PMID:22011750

  10. Cholesterol granuloma and other petrous apex lesions.

    PubMed

    Isaacson, Brandon

    2015-04-01

    This article presents the latest information on the presentation, diagnosis, imaging characteristics, management, and outcomes for petrous apex cholesterol granulomas. An in-depth review of the pathophysiology and surgical approaches is presented along with a summary of other petrous apex lesions and their imaging characteristics.

  11. Degradation of cholesterol crystals in phospholipids

    NASA Astrophysics Data System (ADS)

    Koren, Eugen; Koscec, Mirna; Fugate, Robert D.

    1993-02-01

    Based on previous studies from the laboratory that demonstrated degradation of cholesterol crystals ingested by macrophages in a cell culture system and indicated that intracellular phospholipids could play an important role in mobilization of crystalline cholesterol, the role of each of the three major intracellular phospholipid species in degradation of crystals is further explored. Fluorescently labeled cholesterol crystals are incubated with phospholipids over a period of 5 d. Morphological changes in crystals are monitored using digital imaging fluorescence microscopy, fluorescence redistribution after photobleaching, confocal microscopy, and epifluorescent and phase contrast microscopy. Results clearly demonstrate that all three phospholipids are able to mobilize crystalline cholesterol. However, the mechanisms by which they exert mobilization are different. Sphingomyelin and phosphatidylchloline are found to cause gradual and uniform dissolution of crystals, more or less preserving their original shape. Phosphatidylethanolamine appear to penetrate into the crystal, causing its fragmentation and solubilization. In the mixture of all three phospholipids representing the composition found in macrophages, both of the described mechanisms are working simultaneously.

  12. Garbanzo diet lowers cholesterol in hamsters

    USDA-ARS?s Scientific Manuscript database

    Cholesterol-lowering potential of diets with 22% protein from Chickpea (Cicer arietinum, European variety of Garbanzo, Kabuli Chana), Bengal gram (Cicer arietinum, Asian variety of Garbanzo, Desi Chana, smaller in size, yellow to black color), lentils, soy protein isolate, hydrolyzed salmon protein...

  13. LOADED WAVEGUIDES

    DOEpatents

    Mullett, L.B.; Loach, B.G.; Adams, G.L.

    1958-06-24

    >Loaded waveguides are described for the propagation of electromagnetic waves with reduced phase velocities. A rectangular waveguide is dimensioned so as to cut-off the simple H/sub 01/ mode at the operating frequency. The waveguide is capacitance loaded, so as to reduce the phase velocity of the transmitted wave, by connecting an electrical conductor between directly opposite points in the major median plane on the narrower pair of waveguide walls. This conductor may take a corrugated shape or be an aperature member, the important factor being that the electrical length of the conductor is greater than one-half wavelength at the operating frequency. Prepared for the Second U.N. International ConferThe importance of nuclear standards is duscussed. A brief review of the international callaboration in this field is given. The proposal is made to let the International Organization for Standardization (ISO) coordinate the efforts from other groups. (W.D.M.)

  14. Cholesterol-rich Fluid Membranes Solubilize Ceramide Domains

    PubMed Central

    Castro, Bruno M.; Silva, Liana C.; Fedorov, Alexander; de Almeida, Rodrigo F. M.; Prieto, Manuel

    2009-01-01

    A uniquely sensitive method for ceramide domain detection allowed us to study in detail cholesterol-ceramide interactions in lipid bilayers with low (physiological) ceramide concentrations, ranging from low or no cholesterol (a situation similar to intracellular membranes, such as endoplasmic reticulum) to high cholesterol (similar to mammalian plasma membrane). Diverse fluorescence spectroscopy and microscopy experiments were conducted showing that for low cholesterol amounts ceramide segregates into gel domains that disappear upon increasing cholesterol levels. This was observed in different raft (sphingomyelin/cholesterol-containing) and non-raft (sphingomyelin-absent) membranes, i.e. mimicking different types of cell membranes. Cholesterol-ceramide interactions have been described mainly as raft sphingomyelin-dependent. Here sphingomyelin independence is demonstrated. In addition, ceramide-rich domains re-appear when either cholesterol is converted by cholesterol oxidase to cholestenone or the temperature is decreased. Ceramide is more soluble in cholesterol-rich fluid membranes than in cholesterol-poor ones, thereby increasing the chemical potential of cholesterol. Ceramide solubility depends on the average gel-fluid transition temperature of the remaining membrane lipids. The inability of cholestenone-rich membranes to dissolve ceramide gel domains shows that the cholesterol ordering and packing properties are fundamental to the mixing process. We also show that the solubility of cholesterol in ceramide domains is low. The results are rationalized by a ternary phospholipid/ceramide/cholesterol phase diagram, providing the framework for the better understanding of biochemical phenomena modulated by cholesterol-ceramide interactions such as cholesterol oxidase activity, lipoprotein metabolism, and lipid targeting in cancer therapy. It also suggests that the lipid compositions of different organelles are such that ceramide gel domains are not formed unless a

  15. Cholesterol orientation and tilt modulus in DMPC bilayers

    PubMed Central

    Khelashvili, George; Pabst, Georg; Harries, Daniel

    2010-01-01

    We performed molecular dynamics (MD) simulations of hydrated bilayers containing mixtures of dimyristoylphosphatidylcholine (DMPC) and Cholesterol at various ratios, to study the effect of cholesterol concentration on its orientation, and to characterize the link between cholesterol tilt and overall phospholipid membrane organization. The simulations show a substantial probability for cholesterol molecules to transiently orient perpendicular to the bilayer normal, and suggest that cholesterol tilt may be an important factor for inducing membrane ordering. In particular, we find that as cholesterol concentration increases (1%–40% cholesterol) the average cholesterol orientation changes in a manner strongly (anti)correlated with the variation in membrane thickness. Furthermore, cholesterol orientation is found to be determined by the aligning force exerted by other cholesterol molecules. To quantify this aligning field, we analyzed cholesterol orientation using, to our knowledge, the first estimates of the cholesterol tilt modulus χ from MD simulations. Our calculations suggest that the aligning field that determines χ is indeed strongly linked to sterol composition. This empirical parameter (χ) should therefore become a useful quantitative measure to describe cholesterol interaction with other lipids in bilayers, particularly in various coarse-grained force fields. PMID:20518573

  16. Effects of apolipoproteins on the kinetics of cholesterol exchange

    SciTech Connect

    Letizia, J.Y.; Phillips, M.C. )

    1991-01-22

    The effects of apolipoproteins on the kinetics of cholesterol exchange have been investigated by monitoring the transfer of ({sup 14}C)cholesterol from donor phospholipid/cholesterol complexes containing human apolipoproteins A, B, or C. Negatively charged discoidal and vesicular particles containing purified apolipoproteins complexed with lipid and a trace of ({sup 14}C)cholesterol were incubated with a 10-fold excess of neutral, acceptor, small unilamellar vesicles. The donor and acceptor particles were separated by chromatogrphy of DEAE-Sepharose, and the rate of movement of labeled