| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| Variations in dietary fat and cholesterol intakes modify antioxidant status of SHR and WKY rats Yuan, Y. V., D. D. Kitts, et al. (1998), J Nutr 128(10): 1620-30. Abstract: The effects of varying dietary fat saturation butter (B), beef tallow (BT) or polyunsaturation (n-6) soybean oil (SBO), (n-3) menhaden oil (MO) and cholesterol content (0.05 and 0.5 g/100 g) on systolic blood pressure (SBP), plasma lipids and tissue antioxidant status were investigated in 14-wk-old spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) rats. Varying dietary fat composition for 9 wk had no influence on SBP in either SHR or WKY rats. Rats fed MO diets exhibited smaller (P < 0.05) body weight gains, lower (P < 0.05) feed efficiency ratios and lower (P < 0.05) plasma cholesterol concentrations than those fed the B, BT and SBO diets. Significant (P < 0.05) interactions for animal strain x cholesterol intake and animal strain x fat source were noted for serum cholesterol concentrations. SHR exhibited higher (P < 0.05) RBC and liver catalase (CAT), and heart and liver superoxide dismutase (SOD) activities similar to those of WKY rats. The lower (P <0.01) RBC, heart and liver glutathione peroxidase (GSH-Px) activities observed in SHR coincided with higher (P <0.01) glutathione reductase (GSSG-Red), compared with WKY rats. Dietary cholesterol intake had no effect on RBC, heart and liver total sulfhydryl concentration or GSH-Px activities, but increased (P <0. 001) liver GSSG-Red. Feeding MO resulted in lower (P <0.001) RBC and heart GSH-Px activities. In contrast, feeding B and BT resulted in lower GSH-Px in liver. The significant (P < 0.01) animal strain x fat source interaction obtained for liver GSH-Px activity indicated that SHR responded differently to polyunsaturated fatty acid feeding than their WKY counterparts. Diet-induced changes in tissue antioxidant status were tissue specific and did not affect the development of hypertension in SHR. |
| Variations in high-density lipoprotein cholesterol in relation to physical activity and Taq 1B polymorphism of the cholesteryl ester transfer protein gene Mukherjee, M. and K. R. Shetty (2004), Clin Genet 65(5): 412-8. Abstract: The aim of the study was to determine any association of physical activity and Taq 1B polymorphism in the cholesteryl ester transfer protein gene on high-density lipoprotein (HDL) cholesterol. Five hundred and four subjects, 390 males and 114 females consisting of an equal number of age- and sex-matched healthy controls and patients with coronary artery disease, were included. The mean age (+/-SD) of the patients and controls were 57.5 +/- 10.6 years and 56.8 +/- 11.0 years, respectively. All the patients underwent coronary angiography; 33, 58, 63, and 98 patients had normal coronaries, single-, two-, or triple-vessel disease, respectively. A third of the patients had suffered from a myocardial infarction. The genotype distribution conforming to Hardy-Weinberg equilibrium was similar for cases and controls. The mean HDL cholesterol increased from B1B1 through B2B2 genotype in controls and sedentary male patients. Self-reported leisure time physical activity, consisting mostly of an hour of morning walk daily, was associated with a rise in mean HDL cholesterol in male controls (33.6 +/- 7.9 mg/dl to 36.2 +/- 8.9 mg/dl, p = 0.037) and patients (32.4 +/- 7.9 mg/dl to 35.7 +/- 11.0 mg/dl; p = 0.018). The exercise-associated rise in HDL cholesterol was most pronounced in controls (32.1 +/- 9.1 mg/dl to 36.8 +/- 9.3 mg/dl, p = 0.05) and male patients (30.5 +/- 7.4 mg/dl to 37.2 +/- 9.7 mg/dl, p = 0.007) with B1B1 rather than B1B2 or B2B2 genotype. The results suggest a possible gene-environment interaction in the regulation of HDL cholesterol that needs to be confirmed in other populations and larger samples to rule out a chance occurrence. |
| Variations in lipid and lipoprotein levels during isotretinoin treatment for acne vulgaris with special emphasis on HDL-cholesterol Lestringant, G. G., P. M. Frossard, et al. (1997), Int J Dermatol 36(11): 859-62. Abstract: BACKGROUND: Many studies have demonstrated an increase in total cholesterol and triglycerides on oral isotretinoin therapy. This has led several investigators to comment on the possibility of increased risk for cardiovascular disease. Yet, the status of high density lipoprotein (HDL) in patients on isotretinoin therapy has not been studied extensively. PATIENTS AND METHODS: We studied 104 United Arab Emirates (UAE) nationals (78 women, 26 men) who underwent isotretinoin therapy for acne at doses ranging from 0.2 to 1.6 mg/kg, and determined the lipid and lipoprotein levels before and after an 8-week period of treatment. The risk for cardiovascular disease was evaluated as the ratio of cholesterol/HDL-cholesterol. RESULTS: Mean cholesterol, triglycerides, and low density lipoprotein-cholesterol (LDL-cholesterol) levels rose significantly after treatment (p = 0.01) whereas HDL-cholesterol values decreased significantly (p = 0.01). In the entire subject population, the overall risk for cardiovascular disease rose from 3.45 to 3.67, indicating that these subjects remained in the category considered to have "half-average" to "average" risk of cardiovascular disease. CONCLUSIONS: In young and healthy individuals, significant variations in lipid and lipoprotein levels, resulting from isotretinoin treatment for acne, do not influence the overall risk for cardiovascular disease. Isotretinoin is thus a safe and efficient drug for the treatment of acne in these subjects. |
| Variations in plasma volume affect total and low-density lipoprotein cholesterol concentrations during the menstrual cycle Cullinane, E. M., S. M. Yurgalevitch, et al. (1995), Metabolism 44(8): 965-71. Abstract: Serum lipids are known to vary during the menstrual cycle. To determine if changes in plasma volume contribute to this effect, we determined serum lipids, lipoproteins, and estimated changes in plasma volume in 18 premenopausal women at the start of and at 5-day intervals after menstruation. Eleven men served as a comparison group. Changes in plasma volume were estimated from changes in hemoglobin and hematocrit. Total and low-density lipoprotein (LDL) cholesterol (mean +/- SD) increased 15 +/- 14 mg/dL (9% +/- 10%) and 11 +/- 13 (11% +/- 14%) within 10 days after the start of menstruation (P <.05) and then decreased toward baseline during the rest of the cycle. High-density lipoprotein (HDL) cholesterol increased 3 mg/dL, or 5%, (P <.05) on days 10 and 15 after menstruation. Plasma volume decreased 4% +/- 9% (P <.06) 10 days after the start of menstruation, and this maximum decrease in plasma volume coincided with peak increases in total, LDL, and HDL cholesterol. Except for an 8-mg/dL increase in LDL cholesterol at day 5, lipid changes were no longer significant after adjusting for changes in plasma volume. We conclude that alterations in plasma volume account for approximately half of the increase in total and LDL cholesterol during the menstrual cycle. |
| Variations with age and serum cholesterol level in the topographic distribution of macroscopic aortic atherosclerotic lesions as assessed by image analysis methods Ishii, T., G. T. Malcom, et al. (1990), Mod Pathol 3(6): 713-9. Abstract: The topographic distribution of macroscopic atherosclerotic lesions in the aorta was studied by image analysis of aortas taken at autopsy from 155 males aged 10 to 54 yr. In both the thoracic and abdominal aorta, fatty streaks (FS) appear before raised lesions (RL) affecting preferential areas located longitudinally along the intercostal ostia, at the aorta bifurcation, and surrounding the points of origin of branches of the abdominal aorta. Later RL appear in the same areas of the aortic intima affected by FS at younger ages. As for the effect of serum total cholesterol (TC) in the progression of atherosclerosis, the prevalent involvement areas by FS and RL were similarly distributed as indicated by our analyses. However, areas showing frequent occurrence of FS and RL in each aortic segment were distributed more extensively at identical areas in the higher serum TC groups than in the lower TC level group. Thus, it can be concluded that FS are the precursor lesions of RL in the aorta and that the serum TC promotes the progression of atherosclerosis. |
| Vascular angiotensin-converting enzyme activity in cholesterol-fed rabbits: effects of enalapril Hoshida, S., M. Nishida, et al. (1997), Atherosclerosis 130(1-2): 53-9. Abstract: Many reports have shown inhibitory effects of angiotensin-converting enzyme (ACE) inhibitors on the progression of atherosclerotic plaque lesions in vascular tissue of experimental models. However, no report has shown alterations of ACE activity in vascular tissue during the process of atherosclerosis. We measured ACE activity in plasma and aortic tissue in rabbits fed a cholesterol-rich (1%) or normal diet for 10 weeks. We also evaluated the blood pressure response to angiotensin (Ang) I and II. These data were compared in untreated rabbits and in rabbits receiving chronic treatment with an ACE inhibitor, enalapril (3 mg/kg/day for 10 weeks). ACE activity in aortic tissue, but not in plasma, in cholesterol-fed rabbits was gradually but significantly increased compared with that in noncholesterol-fed rabbits even after the 4-week feeding period, when no atherosclerotic lesion was observed in the aortic tissue. Treatment with enalapril for 10 weeks, but not 4 weeks, significantly reduced the ACE activity in aortic tissue in association with the reductions in the elevated Ang II level and the atherosclerotic plaque area of the aortic tissue. These results indicated that ACE activity in aortic tissue was increased during the early phase of atherosclerotic process. |
| Vascular contraction in perfused carotid arteries of cholesterol-fed rabbits Asada, Y., R. Yamamoto, et al. (1992), Atherosclerosis 94(2-3): 233-9. Abstract: The purpose of the present study was to investigate the effects of hypercholesterolemia on sympathetic vascular responsiveness in the perfused rabbit carotid artery. Two groups of rabbit carotid arteries were evaluated for the simultaneous measurement of noradrenaline (NA) release and vasoconstrictor response induced by electric nerve stimulation and for exogenous NA-induced vasoconstriction in vitro. One group of rabbits was fed a diet containing 0.5% cholesterol for 2 weeks and the other group was fed standard rabbit chow. By scanning electron microscopy, monocytes adhering to the endothelial cells and penetrating into the subendothelium were observed. Neither endothelial denudation nor platelet adhesion could be detected. Rabbit carotid arteries were cannulated and perfused with a physiological solution at a constant flow rate. The vessels were subjected to both transmural field stimulation (TFS; 1.5-24 Hz) and exogenous NA administration. TFS caused a frequency-dependent increase in endogenous NA release with subsequent pressor responses in both groups. Exogenous NA also induced a dose-dependent pressor response, but a significant reduction was observed in the cholesterol-fed group. Methoxamine induced a similar response in both groups. It was concluded that hypercholesterolemia decreased the sensitivity of extrajunctional alpha-receptors in the perfused rabbit carotid artery. |
| Vascular effects of estrogen and cholesterol-lowering therapies in hypercholesterolemic postmenopausal women Koh, K. K., C. Cardillo, et al. (1999), Circulation 99(3): 354-60. Abstract: BACKGROUND: Lipoproteins affect endothelium-dependent vasomotor responsiveness. Because lipoprotein effects of estrogen and cholesterol-lowering therapies differ, we studied the vascular responses to these therapies in hypercholesterolemic postmenopausal women. METHODS AND RESULTS: We randomly assigned 28 women to conjugated equine estrogen (CE) 0.625 mg, simvastatin 10 mg, and their combination daily for 6 weeks. Compared with respective baseline values, simvastatin alone and combined with CE reduced LDL cholesterol to a greater extent than CE alone (both P<0.05). CE alone and combined with simvastatin raised HDL cholesterol and lowered lipoprotein(a) to a greater extent than simvastatin alone (all P<0.05). Flow-mediated dilation of the brachial artery (by ultrasonography) improved (all P<0.001 versus baseline values) on CE (4.0+/-2.6% to 10.2+/-3.9%), simvastatin (4.3+/-2.4% to 10.0+/-3.9%), and CE combined with simvastatin (4.6+/-2.0% to 9.8+/-2.6%), but similarly among therapies (P=0.507 by ANOVA). None of the therapies improved the dilator response to nitroglycerin (all P>/=0.184). Only therapies including CE lowered levels of plasminogen activator inhibitor type 1 and the cell adhesion molecule E-selectin (all P<0. 05 versus simvastatin). CONCLUSIONS: Although estrogen and statin therapies have differing effects on lipoprotein levels, specific improvement in endothelium-dependent vasodilator responsiveness is similar. However, only therapies including estrogen improved markers of fibrinolysis and vascular inflammation. Thus, estrogen therapy appears to have unique properties that may benefit the vasculature of hypercholesterolemic postmenopausal women, even if they are already on cholesterol-lowering therapy. |
| Vastatins inhibit cholesterol ester accumulation in human monocyte-derived macrophages Kempen, H. J., M. Vermeer, et al. (1991), Arterioscler Thromb 11(1): 146-53. Abstract: Human monocyte-derived macrophages were incubated for 48 hours in Medium 199 with 1% human serum albumin, and with 100 micrograms acetyl low density lipoprotein (LDL) or beta-very low density lipoprotein (beta-VLDL), with or without various concentrations of compactin, lovastatin, simvastatin, or pravastatin. The mass of free (FC) and esterified (CE) cholesterol was determined, as well as the incorporation of 1-14Cacetate in sterols, that of 1-14Coleate in CE, and that of methyl-14Ccholine in phospholipids. Moreover, we assessed the high-affinity association and degradation of 125I-labeled acetyl LDL. Compactin markedly decreased the cellular accumulation of CE induced by acetyl LDL or beta-VLDL and increased the content of FC. Compactin also decreased the incorporation of 1-14Coleate in CE (by 70-90%) in incubations with or without added lipoproteins. The half-maximal inhibitory concentration for this effect of compactin was 30 nM. Lovastatin and simvastatin were more potent, but pravastatin was about 100-fold less potent. Although compactin also caused a clear inhibition of cholesterol synthesis in the presence of acetyl LDL, the effect on CE formation did not seem to be related to decreased cholesterol synthesis, since this was already very low in the presence of acetyl LDL. Compactin did not affect the association and degradation of labeled acetyl LDL and also had no effect on the rate of cholesterol loss after preloading the cells with CE by incubation with acetyl LDL. However, compactin had a slight stimulatory effect on the synthesis of phosphatidylcholine and sphingomyelin when compactin was added to incubations in the presence of acetyl LDL.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Vegetarians have higher plasma alpha-tocopherol relative to cholesterol than do nonvegetarians Pronczuk, A., Y. Kipervarg, et al. (1992), J Am Coll Nutr 11(1): 50-5. Abstract: Biological antioxidants are thought to play a protective role in certain disease processes, including atherosclerosis. To compare the relative antioxidant/atherogenic risk between vegetarians (presumed lower risk) and omnivores (higher risk), the alpha-tocopherol, total cholesterol and fatty acid (FA) profiles were determined in the plasma of 79 vegetarians (28 males, 51 females) and 79 age- and sex-matched nonvegetarians. In the vegetarian group, mean (+/- SEM) plasma alpha-tocopherol was 714 +/- 46 micrograms/dl for males and 725 +/- 24 for females; corresponding cholesterol values were 122 +/- 5 mg/dl and 138 +/- 3, respectively, which were significantly lower than the respective control values (928 +/- 38; 883 +/- 23 and 206 +/- 6; 188 +/- 4). However, when plasma tocopherol was expressed in terms of cholesterol, the tocopherol: cholesterol molar ratio was significantly enhanced for both male (27%) and female (11%) vegetarians. Vegetarians also had a lower atherosclerosis risk based on their plasma FA profile (higher linoleic:oleic acid ratio) which correlated well (r = 0.72; p less than 0.001) with plasma alpha-tocopherol:cholesterol molar ratio. Since the bulk of tocopherol is transported in low-density lipoprotein, this lipoprotein in vegetarians may be better protected against lipid peroxidation, a process believed to be important in the pathogenesis of atherosclerosis. |
| Verapamil enhances high-density lipoprotein processing in Hep G2 cells preloaded with cholesterol Chappey-Gillet, B., S. Salmon, et al. (1990), Biochim Biophys Acta 1052(2): 273-7. Abstract: The effects of the calcium channel blocker of the arylalkylamine series verapamil have been investigated on high-density lipoprotein (HDL3) catabolism in the human hepatoma cell line Hep G2. It was found that verapamil markedly enhanced HDL3 binding, uptake and degradation in Hep G2 cells preloaded with nonlipoprotein cholesterol. This effect was dose-dependent, and a 1.5-2-fold increase of the three studied parameters was observed in cells pretreated 24 h with 100 microM verapamil. No significant effect of the drug was found in cells not preincubated with cholesterol. Verapamil induced an increase in the cellular cholesterol content in preloaded cells. Other calcium antagonists such as diltiazem, nifedipine, nitrendipine or amphiphilic drugs such as phenothiazines and propranolol also enhanced HDL3 uptake by Hep G2 cells. These effects of verapamil on HDL3 metabolism could be related to its amphiphilic characteristics, and to its calcium antagonist properties. |
| Verapamil increases the apolipoprotein-mediated release of cellular cholesterol by induction of ABCA1 expression via Liver X receptor-independent mechanism Suzuki, S., T. Nishimaki-Mogami, et al. (2004), Arterioscler Thromb Vasc Biol 24(3): 519-25. Abstract: OBJECTIVE: Release of cellular cholesterol and phospholipid mediated by helical apolipoprotein and ATP-binding cassette transporter (ABC) A1 is a major source of plasma HDL. We investigated the effect of calcium channel blockers on this reaction. METHODS AND RESULTS: Expression of ABCA1, apoA-I-mediated cellular lipid release, and HDL production were enhanced in cAMP analogue-treated RAW264 cells by verapamil, and similar effects were also observed with other calcium channel blockers. The verapamil treatment resulted in rapid increase in ABCA1 protein and its mRNA, but not the ABCG1 mRNA, another target gene product of the nuclear receptor liver X receptor (LXR). By using the cells transfected with a mouse ABCA1 promoter-luciferase construct (-1238 to +57bp), verapamil was shown to enhance the transcriptional activity. However, it did not increase transcription of LXR response element-driven luciferase vector. CONCLUSIONS: The data demonstrated that verapamil increases ABCA1 expression through LXR-independent mechanism and thereby increases apoA-I-mediated cellular lipid release and production of HDL. |
| Verification of hypocholesterolemic effect of fermented milk on human subjects with different cholesterol levels Ashar, M. N. and J. B. Prajapati (2000), Folia Microbiol (Praha) 45(3): 263-8. Abstract: The possible hypocholesterolemic effect of acidophilus milk was evaluated on 27 human subjects having different levels of serum cholesterol, i.e. < 2.0 (group C1), 2.0-2.2 (C2), 2.2-2.5 (C3) and > 2.5 g/L (C4). The acidophilus milk was prepared by fermentation of low-fat milk with Lactobacillus acidophilus and was fed to each volunteer at the rate of 200 mL/d for 20 d. Blood samples from the volunteers were collected and analyzed for lipid profile twice prior to, during and after feeding, keeping a gap of 10 d between two collections. A significant decrease (p < 0.05) in average total cholesterol was found in the C2 and C3 groups, amounting to 21 and 12%, respectively. The average LDL cholesterol decreased in C2, C3 and C4 groups by 0.54, 0.26 and 0.46 g/L, respectively. In the C2 group, the LDL/HDL and total/HDL ratio was also reduced by 1.4 and 1.3, respectively. However, in the C1 group, the average total and LDL cholesterol level did not show any significant change but serum triacylglycerols and VLDL cholesterol showed a significant (p < 0.05) increase of 0.53 and 0.11 g/L, respectively. Regression analysis of the data revealed a square trend in most of the parameters over time period. Overall, the feeding had the best effect in the subjects with lipidemic status of borderline cholesterol level (2.0-2.2 g/L) group. |
| Very high values of serum high-density lipoprotein cholesterol Weitzman, J. B. and A. O. Vladutiu (1992), Arch Pathol Lab Med 116(8): 831-6. Abstract: Little is known about individuals who have very high values of serum high-density lipoprotein cholesterol (HDL-C) with the exception of those who have very rare genetic conditions, eg, familial hyperalphalipoproteinemia or hypobetalipoproteinemia. During a period of 60 months of testing for HDL-C, we found 46 individuals (of whom 43 were women) who had an HDL-C level equal to or higher than 2.58 mmol/L (greater than or equal to 100 mg/dL) (range, 2.58 to 6.15 mmol/L 100 to 238 mg/dL). Sixteen of these individuals were treated with estrogens or ranitidine or were alcoholic, and several had evidence of coronary heart disease. We conclude that very high values of HDL-C can be found in the general population mostly in women, and this is often related to environmental causes, eg, the use of H2-blockers, estrogens, and alcohol. The finding of very elevated HDL-C levels in serum is probably not always due to a genetic condition and does not always signify absence of coronary heart disease and increased life expectancy. |
| Very long chain fatty acids (policosanols) and phytosterols affect plasma lipid levels and cholesterol biosynthesis in hamsters Wang, Y., N. Ebine, et al. (2005), Metabolism 54(4): 508-14. Abstract: The aim of the current study was to examine the effects of very long chain fatty acids (VLCFA) alone at 2 dietary levels, or in combination of VLCFA at the lower level with lecithin (LT) or phytosterols (PS), on lipid profiles and cholesterol biosynthesis in hamsters. Seventy-five male Golden Syrian hamsters, weighing 100 to 120 g, were fed a regular rodent chow for 2 weeks before being randomly assigned into 5 groups of 15 animals each fed semisynthetic diets for 4 weeks. Group 1 was given a control diet that contained 0.25% cholesterol and 5% fat with a polyunsaturated to saturated fatty acids ratio of 0.4. Groups 2 to 5 were fed the control diet and given 25 mg/kg BW per day of VLCFA (Licowax) (VLCFA25), 50 mg/kg BW per day of VLCFA (VLCFA50), 25 mg/kg BW per day of VLCFA+1000 mg/kg BW per day of LT (VLCFA25/LT), and 25 mg/kg BW per day of VLCFA+1000 mg/kg BW per day of PS (Cholestatin, VLCFA25/PS), respectively. Results showed that HDL-cholesterol (HDL-C) levels were not changed by VLCFA25, although increased by VLCFA50 (P<.05) relative to control. Total cholesterol (T-C) and non-HDL-C levels were not affected by VLCFA25 and VLCFA50 as compared with control. VLCFA25/LT had higher (P<.02) T-C and HDL-C levels than any other treatments and increased (P<.05) liver weight relative to control. In contrast, VLCFA25/PS reduced T-C (P=.0004) and non-HDL-C (P=.007) without effect on HDL-C levels compared with control. Triglyceride levels were not affected by any treatment. Cholesterol biosynthesis rate was higher (P<.05) in animals fed VLCFA25 and VLCFA50 than those fed control or VLCFA25/LT or VLCFA25/PS. Results suggest that PSs can decrease total and non-HDL-C cholesterol, whereas VLCFA may increase HDL-C in hamsters. |
| Very long chain PUFA in murine testicular triglycerides and cholesterol esters Furland, N. E., E. N. Maldonado, et al. (2003), Lipids 38(1): 73-80. Abstract: Very long chain (VLC) PUFA of the n-6 and n-3 series are known to occur in mammalian testis. The aim of this work was to characterize further two testicular lipid classes with VLCPUFA, cholesterol esters (CE) and total triglycerides (TG) in rat and mouse testis. The VLCPUFA predominating in these lipids were a series of n-6 pentaenes and tetraenes with 24 to 32 carbons, including small amounts of odd-chain PUFA, 28:5n-6 and 24:5n-6 prevailing in CE and TG, respectively. Most of the VLCPUFA of TG were concentrated in a small fraction of TG, made up by 1-O-alkyl-2,3-DAG. This TG subclass was absent altogether from the TG of sexually immature testis. The TG and the CE with VLCPUFA only occurred in testis of adult fertile animals. The proportion of VLCPUFA in total TG and CE was higher in rodents than in other mammals. In the n-6 PUFA-rich adult mouse testis, the amounts of testicular triacylglycerols decreased significantly after consumption of fish oil for 2 wk. Whereas 18:2n-6 was significantly reduced, the amounts of 22:5n-6 and longer n-6 PUFA were less affected in all major testicular lipids including PC and PE, where they were unchanged. The 1-O-alkyl-2,3-DAG and their n-6 VLCPUFA were virtually unaffected by the diet. The VLCPUFA-containing molecular species of CE and TG may represent a form of storage of cholesterol and polyenoic FA required to sustain spermatogenesis. Via chain-shortening, VLCPUFA stored in the neutral lipids may serve as precursors of the major C22 PUFA typical of cell membrane glycerophospholipids, protecting testicular cells against shifts in FA composition induced by dietary changes. |
| Very low cholesterol and cholesterol lowering. A statement for healthcare professionals from the American Heart Association Task Force on Cholesterol Issues Criqui, M. H. (1994), Circulation 90(5): 2591. |
| Very low intakes of N-3 fatty acids incorporated into bovine milk reduce plasma triacylglycerol and increase HDL-cholesterol concentrations in healthy subjects Visioli, F., P. Rise, et al. (2000), Pharmacol Res 41(5): 571-6. Abstract: Eight normolipidaemic volunteers, habitual partial skim milk drinkers and non-eaters of fish during the study, were given 500 ml day(-1) of partial skim milk for 1 month; they were then switched to 500 ml day(-1) of a novel commercially available milk preparation, supplying 400 mg of N-3 fatty acids-of which 300 mg were EPA+DHA-and 15 mg vitamin E, for 6 weeks. No changes in plasma lipid parameters were observed after the first run-in month; at 3 and 6 weeks on the N-3-rich milk, marked increments of plasma EPA (44 and 31%, respectively) and DHA (13 and 31%, respectively) were observed. Triacylglycerol (TG) concentrations decreased by 19% and high-density lipoprotein (HDL) concentrations increased by 19% at 6 weeks; plasma vitamin E rose by 21% while the susceptibility of plasma to oxidation was unaffected. Correlations were found between plasma EPA or DHA and TG, cholesterol, and HDL. In conclusion, the intake of a milk preparation providing low amounts of EPA+DHA to healthy individuals led to marked increases of N-3 fatty acids and vitamin E in plasma and in associated favourable changes in HDL and TG. |
| Very low levels of high density lipoprotein cholesterol in four sibs of a family with non-neuropathic Niemann-Pick disease and sea-blue histiocytosis Viana, M. B., R. Giugliani, et al. (1990), J Med Genet 27(8): 499-504. Abstract: Very low serum levels of high density lipoprotein cholesterol ranging from 8.6 to 13.9 mg/dl were detected in four out of 12 sibs of a Brazilian kindred with the non-neuropathic form of Niemann-Pick disease. Hepatosplenomegaly, interstitial infiltration of the lungs, absence of neurological signs, sea-blue histiocytes in the bone marrow and liver, and high values for serum acid phosphatase (18 to 32 U/l) were common to all affected children. Leucocyte acid sphingomyelinase activity ranged from 3.6 to 6.5% of mean control values, and fibroblast activity from 9 to 13% of mean controls. The parents had low-normal levels. The relationship between these findings is unclear and deserves further investigation. |
| Vesicles and mixed micelles in hypothyroid rat bile before and after thyroid hormone treatment: evidence for a vesicle transport system for biliary cholesterol secretion Andreini, J. P., W. F. Prigge, et al. (1994), J Lipid Res 35(8): 1405-12. Abstract: Hypothyroid rats show reduced secretion of biliary lipids, especially cholesterol. Secretion of biliary cholesterol is markedly augmented to levels above euthryroid beginning 12-24 h after administration of thyroid hormone. In the current studies, bile from hypothyroid and triiodothyronine-treated chronic bile-fistula rats was analyzed for vesicles and mixed micelles by metrizamide gradient ultracentrifugation. For euthryoid and hypothyroid animals, less than 12% of biliary cholesterol was in a vesicle gradient fraction. After treatment with triiodothyronine, biliary cholesterol increased markedly, and 50% of total cholesterol, 60% of excess cholesterol secreted, appeared in the vesicle fraction. Triiodothyronine stimulation of vesicle secretion resulted in cholesterol-rich vesicles (cholesterol:phospholipid ratio rose from less than 0.1 to 0.56), but no change in the distinct fatty acid composition of vesicle phospholipids. The microtubule inhibitor colchicine, given 12 h after triiodothyronine, prevented subsequent increase in cholesterol secretion in the form of vesicles. These studies, in a model that allows rapid changes in biliary lipid secretion, support the hypothesis that an important component of cholesterol and phospholipid secretion into bile involves microtubules and may involve a vesicle pathway. |