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Molecules (Basel, Switzerland) Nov 2011Synthesis, detailed structural characterization (X-ray, NMR, MS, IR, elemental analysis), and studies of toxicity, antioxidant activity and bioavailability of unique...
Synthesis, detailed structural characterization (X-ray, NMR, MS, IR, elemental analysis), and studies of toxicity, antioxidant activity and bioavailability of unique potent anti-atherosclerotic succinobucol-steroid conjugates are reported. The conjugates consist of, on one side, the therapeutically important drug succinobucol ([4-{2,6-di-tert-butyl-4-[(1-{[3-tert-butyl-4-hydroxy-5-(propan-2-yl)phenyl]sulfanyl}ethyl)sulfanyl]phenoxy}-4-oxo-butanoic acid]) possessing an antioxidant and anti-inflammatory activity, and on the other side, plant stanol/sterols (stigmastanol, β-sitosterol and stigmasterol) possessing an ability to lower the blood cholesterol level. A cholesterol-succinobucol prodrug was also prepared in order to enhance the absorption of succinobucol through the intestinal membrane into the organism and to target the drug into the place of lipid metabolism-The enterohepatic circulation system. Their low toxicity towards mice fibroblasts at maximal concentrations, their antioxidant activity, comparable or even higher than that of ascorbic acid as determined by direct quenching of the DPPH radical, and their potential for significantly altering total and LDL cholesterol levels, suggest that these conjugates merit further studies in the treatment of cardiovascular or other related diseases. A brief discussion of succinobucol's ability to quench the radicals, supported with a computational model of the electrostatic potential mapped on the electron density surface of the drug, is also presented.
Topics: 3T3 Cells; Animals; Anti-Inflammatory Agents; Antioxidants; Biological Availability; Biphenyl Compounds; Clinical Trials as Topic; Fibroblasts; Free Radicals; Humans; Mice; Mice, Inbred BALB C; Molecular Structure; Picrates; Probucol; Static Electricity; Steroids
PubMed: 22075571
DOI: 10.3390/molecules16119404 -
Journal of Atherosclerosis and... Sep 2010Sitosterolemia is a rare, autosomal recessive inherited sterol storage disease associated with high tissue and serum plant sterol concentrations, caused by mutations in... (Review)
Review
Sitosterolemia is a rare, autosomal recessive inherited sterol storage disease associated with high tissue and serum plant sterol concentrations, caused by mutations in the adenosine triphosphate-bind-ing cassette (ABC) transporter ABCG5 or ABCG8 genes. Markedly increased serum concentration of plant sterols. such as sitosterol and campesterol, cause premature atherosclerosis and massive xanthomas. Hitherto known treatments for sitosterolemia, including a low-sterol diet, bile-salt binding resins, ileal bypass surgery and low density lipoprotein (LDL) apheresis have not yielded sufficient reduction of serum plant sterol levels and many patients show a sustained elevation of plant sterol levels, subsequently developing premature atherosclerotic cardiovascular diseases. Ezetimibe, an inhibitor of intestinal cholesterol absorption through its binding to Niemann-Pick C1-like 1 (NPC1L1), has been widely used for decreasing serum LDL-cholesterol levels in patients with hypercholesterolemia. Ezetimibe also reduces the gastrointestinal absorption of plant sterols, thereby also lowering the serum concentrations of plant sterols. This pharmacological property of ezetimibe shows its potential as a novel effective therapy for sitosterolemia. In the current review, we discuss the current therapy for patients with sitosterolemia and present two Japanese adolescent patients with this disease, one of whom underwent percutaneous coronary intervention for accelerated coronary atherosclerosis. Ezetimibe administration in addition to conventional drug therapy successfully reduced serum sitosterol levels by 51.3% and 48.9%, respectively, in the two patients, demonstrating ezetimibe as a novel and potent treatment agent for sitosterolemia that could work additively with conventional drug therapy.
Topics: ATP Binding Cassette Transporter, Subfamily G, Member 5; ATP-Binding Cassette Transporters; Adolescent; Anticholesteremic Agents; Azetidines; Bile Acids and Salts; Cardiovascular Diseases; Ezetimibe; Female; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Ileum; Ion Exchange Resins; Lipid Metabolism, Inborn Errors; Lipoproteins; Male; Models, Biological; Mutation, Missense; Phytosterols; Sitosterols; Young Adult
PubMed: 20543520
DOI: 10.5551/jat.4614 -
Biochimica Et Biophysica Acta Jun 2010The phase behavior of mixtures formed with palmitic acid (PA) and one of the following sterols (dihydrocholesterol, ergosterol, 7-dehydrocholesterol, stigmasterol and...
The phase behavior of mixtures formed with palmitic acid (PA) and one of the following sterols (dihydrocholesterol, ergosterol, 7-dehydrocholesterol, stigmasterol and stigmastanol), in a PA/sterol molar ratio of 3/7, has been characterized by IR and (2)H NMR spectroscopy at different pH. Our study shows that it is possible to form liquid-ordered (lo) lamellar phases with these binary non-phospholipid mixtures. The characterization of alkyl chain dynamics of PA in these systems revealed the large ordering effect of the sterols. It was possible to extrude these systems, using standard extrusion techniques, to form large unilamellar vesicles (LUVs), except in the case of ergosterol-containing mixture. The resulting LUVs displayed a very limited passive permeability consistent with the high sterol concentration. In addition, the stability of these PA/sterol self-assembled bilayers was also found to be pH-sensitive, therefore, potentially useful as nanovectors. By examining different sterols, we could establish some correlations between the structure of these bilayers and their permeability properties. The structure of the side chain at C17 of the sterol appears to play a prime role in the mixing properties with fatty acid.
Topics: Liposomes; Magnetic Resonance Spectroscopy; Palmitic Acid; Sterols
PubMed: 20153720
DOI: 10.1016/j.bbamem.2010.02.008 -
The Journal of Biological Chemistry Jan 2010Plant sterols may induce a Th1 shift in humans. However, whether plant stanols have similar effects as well as the underlying mechanism are unknown. We have now shown...
Plant sterols may induce a Th1 shift in humans. However, whether plant stanols have similar effects as well as the underlying mechanism are unknown. We have now shown that (like sitosterol) sitostanol, both 4-desmethylsterols, induces a Th1 shift when added in vitro at physiological concentrations to human PBMCs. This conclusion was based on a higher IFNgamma production, with no change in the production of IL-4 and IL-10. alpha-Amyrin, a 4.4-dimethylsterol, had comparable effects. Because 4.4-dimethylsterols cannot activate transcription factor LXR, this finding indicates that LXR activation was not involved. Sitosterol and sitostanol did not alter the production of IL-12 and IL-18 in PBMCs as well as in monocyte-derived U937 cells, suggesting that plant sterols directly affect T-helper cells, without activating APCs. However, in PBMCs treated with a TLR2 blocker (T2.5), IFNgamma production was completely inhibited, whereas blocking TLR4 with HTA125 had no such effect. To confirm these findings, PBMCs from TLR2(-/-) mice were cultured in the presence of sitosterol and sitostanol. In these cells, no Th1 shift was observed. Our results, therefore, indicate that TLR2 activation is essential to induce a Th1 shift in human PBMCs by plant stanols and plant sterols.
Topics: Animals; Humans; Interferon-gamma; Interleukin-12; Interleukin-18; Leukocytes, Mononuclear; Liver X Receptors; Mice; Mice, Inbred C57BL; Mice, Transgenic; Orphan Nuclear Receptors; Phytosterols; Plants; Sitosterols; Th1 Cells; Toll-Like Receptor 2; U937 Cells
PubMed: 19948716
DOI: 10.1074/jbc.M109.036343 -
Lipids in Health and Disease Jul 2009The aim of this work was to assess the effect of chronic administration of protonated nanostructured aluminosilicate (NSAS) on the plasma cholesterol levels and...
Protonated nanostructured aluminosilicate (NSAS) reduces plasma cholesterol concentrations and atherosclerotic lesions in Apolipoprotein E deficient mice fed a high cholesterol and high fat diet.
The aim of this work was to assess the effect of chronic administration of protonated nanostructured aluminosilicate (NSAS) on the plasma cholesterol levels and development of atherosclerotic lesions in Apolipoprotein (ApoE) deficient mice fed a high cholesterol and high fat diet. Apolipoprotein E (ApoE) deficient mice were divided into the following treatment groups: protonated NSAS 1.4% (w/w), untreated control and 2% (w/w) stigmastanol mixed with high-cholesterol/high-fat diet. Animals were treated for 12 weeks, blood samples were withdrawn every 4 weeks for determination of plasma cholesterol and triglyceride levels. At the end of the study the aortic roots were harvested for assessment of atherosclerotic lesions. NSAS at 1.4% (w/w) and stigmastanol at 2% (w/w) treatment groups showed significant decreases in plasma cholesterol concentrations at all time points relative to the control animals. The lesion sum area in 1.4% (w/w) NSAS and 2% (w/w) stigmastanol groups were significantly less from the control animals. In conclusion, in this study, the effectiveness of chronic administration of protonated NSAS material in the reduction of plasma cholesterol levels and decrease in development of atherosclerotic lesions was demonstrated in Apo-E deficient mice model.
Topics: Aluminum Silicates; Animals; Anticholesteremic Agents; Aorta; Aortic Diseases; Apolipoproteins E; Atherosclerosis; Bentonite; Body Weight; Cholesterol; Cholesterol, Dietary; Dietary Fats; Disease Models, Animal; Metal Nanoparticles; Mice; Mice, Inbred C57BL; Mice, Knockout; Molecular Structure; Triglycerides
PubMed: 19638223
DOI: 10.1186/1476-511X-8-30 -
Arteriosclerosis, Thrombosis, and... Jul 2008We examined the effect of ezetimibe, a cholesterol absorption (CA) inhibitor, and genetic determinants of CA on reverse cholesterol transport (RCT) from subcutaneously...
OBJECTIVE
We examined the effect of ezetimibe, a cholesterol absorption (CA) inhibitor, and genetic determinants of CA on reverse cholesterol transport (RCT) from subcutaneously injected macrophages using a new dual isotope label technique.
METHODS AND RESULTS
Treatment of C57BL/6J mice with ezetimibe decreased dietary CA by 86% and increased RCT from peripheral tissue macrophages (PTM) by 6-fold (P<0.0001). Moreover, congenic 14DKK mice with a modest 41% decrease in dietary CA displayed a 67% increase in RCT from PTM (P<0.007).
CONCLUSIONS
These findings indicate that pharmacological and genetic modifiers of cholesterol absorption are major determinants of reverse cholesterol transport from peripheral tissue macrophages.
Topics: Animals; Anticholesteremic Agents; Azetidines; Cell Line; Cell Transplantation; Cholesterol, Dietary; Ezetimibe; Feces; Female; Intestinal Absorption; Intestines; Kinetics; Lipid Metabolism; Macrophages; Mice; Mice, Congenic; Mice, Inbred C57BL; Sitosterols
PubMed: 18420997
DOI: 10.1161/ATVBAHA.108.165803 -
Biophysical Journal Oct 2006Pulsed field gradient (pfg)-NMR spectroscopy was utilized to determine lipid lateral diffusion coefficients in oriented bilayers composed of 25 mol % sterol and...
Pulsed field gradient (pfg)-NMR spectroscopy was utilized to determine lipid lateral diffusion coefficients in oriented bilayers composed of 25 mol % sterol and equimolar amounts of dioleoylphosphatidylcholine and sphingomyelin. The occurrence of two lipid diffusion coefficients in a bilayer was used as evidence of lateral phase separation into liquid ordered and liquid disordered domains. It was found that cholesterol, ergosterol, sitosterol, and lathosterol induced domains, whereas lanosterol, stigmasterol, and stigmastanol resided in homogeneous membranes in the temperature interval of 24-70 degrees C. Among the domain-forming sterols, differences in the upper miscibility temperature indicated that the stability of the liquid ordered phase could be modified by small changes in the sterol structure. The domain-forming capacity for the different sterols is discussed in terms of the ordering effect of the sterols on the lipids, and it is proposed that the driving force for the lateral phase separation is the reduced solubility of the unsaturated lipid in the highly ordered phase.
Topics: Lipid Bilayers; Magnetic Resonance Spectroscopy; Membrane Microdomains; Phase Transition; Phosphatidylcholines; Sphingomyelins; Sterols; Temperature
PubMed: 16829566
DOI: 10.1529/biophysj.106.085480 -
Journal of Lipid Research Nov 2005Plant stanols and sterols of the 4-desmethyl family (e.g., sitostanol and sitosterol) effectively decrease LDL cholesterol concentrations, whereas 4,4-dimethylsterols...
Plant stanols and sterols of the 4-desmethyl family (e.g., sitostanol and sitosterol) effectively decrease LDL cholesterol concentrations, whereas 4,4-dimethylsterols (alpha-amyrin and lupeol) do not. Serum carotenoid concentrations, however, are decreased by both plant sterol families. The exact mechanisms underlying these effects are not known, although effects on micellar composition have been suggested. With a liver X receptor (LXR) coactivator peptide recruitment assay, we showed that plant sterols and stanols from the 4-desmethylsterol family activated both LXRalpha and LXRbeta, whereas 4,4-dimethyl plant sterols did not. In fully differentiated Caco-2 cells, the functionality of this effect was shown by the increased expression of ABCA1, one of the known LXR target genes expressed by Caco-2 cells in measurable amounts. The LXR-activating potential of the various plant sterols/stanols correlated positively with ABCA1 mRNA expression. Reductions in serum hydrocarbon carotenoids could be explained by the effects of the 4-desmethyl family and 4,4-dimethylsterols on micellar carotenoid incorporation. Our findings indicate that the decreased intestinal absorption of cholesterol and carotenoids by plant sterols and stanols is caused by two distinct mechanisms.
Topics: ATP Binding Cassette Transporter 1; ATP-Binding Cassette Transporters; Antioxidants; Caco-2 Cells; Carotenoids; Cholesterol; Cholesterol, LDL; DNA-Binding Proteins; Humans; Hydrocarbons; Intestinal Absorption; Intestines; Liver X Receptors; Micelles; Models, Chemical; Oleanolic Acid; Orphan Nuclear Receptors; Pentacyclic Triterpenes; Peptides; Phytosterols; Plant Extracts; RNA, Messenger; Receptors, Cytoplasmic and Nuclear; Receptors, Steroid; Sitosterols; Sterol Regulatory Element Binding Protein 2; Triterpenes
PubMed: 16150823
DOI: 10.1194/jlr.M500272-JLR200 -
Journal of Lipid Research Jul 2004In the present study, we investigated whether intestinal sterol efflux transporters Abcg5 and Abcg8 play a major role in determining variations in cholesterol (Ch)... (Comparative Study)
Comparative Study
In the present study, we investigated whether intestinal sterol efflux transporters Abcg5 and Abcg8 play a major role in determining variations in cholesterol (Ch) absorption efficiency, and we compared the physiological functions of the duodenal, jejunal, and ileal Abcg5 and Abcg8 on the absorption of Ch and sitostanol in inbred mice challenged with various amounts of Ch, sitostanol, hydrophilic, or hydrophobic bile acids. We found that Abcg5 and Abcg8 in the jejunum and ileum, but not in the duodenum, were main factors in determining, in part, variations in Ch absorption efficiency. The jejunal and ileal Abcg5 and Abcg8 played a major regulatory role in response to high dietary cholesterol and were more sensitive in the regulation of Ch absorption when compared with sitostanol absorption. These results, combined with different sterol uptake rates, suggest that the absorption efficiency of Ch and sitostanol is determined by the net results between influx and efflux of intraluminal Ch and sitostanol molecules crossing the apical membrane of the enterocyte. Hydrophilic and hydrophobic bile acids influenced Ch absorption through mediating Ch solubilization and its physical-chemical state within the small intestinal lumen. We conclude that Ch absorption is mainly regulated by the jejunal and ileal Abcg5 and Abcg8 in mice.
Topics: ATP Binding Cassette Transporter, Subfamily G, Member 5; ATP Binding Cassette Transporter, Subfamily G, Member 8; ATP-Binding Cassette Transporters; Animals; Bile Acids and Salts; Cholesterol; Duodenum; Hydrophobic and Hydrophilic Interactions; Ileum; Intestinal Absorption; Jejunum; Lipoproteins; Mice; Sitosterols
PubMed: 15102882
DOI: 10.1194/jlr.M400030-JLR200 -
Journal of Lipid Research May 2003The rate of intestinal cholesterol (Ch) absorption is an important criterion for quantitation of Ch homeostasis. However, studies in the literature suggest that percent... (Comparative Study)
Comparative Study
Measurement of intestinal cholesterol absorption by plasma and fecal dual-isotope ratio, mass balance, and lymph fistula methods in the mouse: an analysis of direct versus indirect methodologies.
The rate of intestinal cholesterol (Ch) absorption is an important criterion for quantitation of Ch homeostasis. However, studies in the literature suggest that percent Ch absorption, measured usually by a fecal dual-isotope ratio method, spans a wide range, from 20% to 90%, in healthy inbred mice on a chow diet. In the present study, we adapted four standard methods, one direct (lymph collection) and three indirect (plasma and fecal dual-isotope ratio, and sterol balance) measurements of Ch absorption and applied them to mice. Our data establish that all methodologies can be valid in mice, with all methods supporting the concept that gallstone-susceptible C57L mice absorb significantly more Ch (37 +/- 5%) than gallstone-resistant AKR mice (24 +/- 4%). We ascertained that sources of error in the literature leading to marked differences in Ch absorption efficiencies between laboratories relate to a number of technical factors, most notably expertise in mouse surgery, complete solubilization and delivery of radioisotopes, appropriate collection periods for plasma and fecal samples, and total extraction of radioisotopes from feces. We find that all methods provide excellent interexperimental agreement, and the ranges obtained challenge previously held beliefs regarding the spread of intestinal Ch absorption efficiencies in mice. The approaches documented herein provide quantifiable methodologies for exploring genetic mechanisms of Ch absorption, and for investigating the assembly and secretion of chylomicrons, as well as intestinal lipoprotein metabolism in mice.
Topics: Administration, Oral; Algorithms; Animals; Bile Acids and Salts; Biological Transport; Carbon Radioisotopes; Cholesterol; Cricetinae; Dogs; Dose-Response Relationship, Drug; Feces; Female; Guinea Pigs; Humans; Injections, Intravenous; Intestinal Absorption; Lymphatic System; Male; Methods; Mice; Mice, Inbred AKR; Mice, Inbred C57BL; Mice, Inbred Strains; Palmitic Acid; Primates; Rabbits; Rats; Sitosterols; Time Factors; Tritium
PubMed: 12588946
DOI: 10.1194/jlr.D200041-JLR200