| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| Gemfibrozil and Mediterranean diet for patients with high plasma levels of lipoprotein Lp(a) and cholesterol--pilot study Simoni, G., A. Gianotti, et al. (1995), Cardiovasc Drugs Ther 9(2): 347-50. Abstract: Plasma levels of lipoprotein-a Lp(a) > 30 mg/dl represent an independent risk factor for cardiovascular diseases with both proatherosclerotic and prothrombotic activity. The results of dietary or pharmacological treatment are not encouraging and are often controversial. We have evaluated a combination of medical treatment with Gemfibrozil (600 mg bid) and a Mediterranean diet for 2 months in 15 patients with both hypercholesterolemia (> 240 mg/dl) and high levels of Lp(a) (> 30 mg/dl). Three patients dropped out within the first 2 weeks, complaining of epigastric pain and burning; the remainder (5 females and 7 males, mean age 70 years) completed the treatment without any side effects. The median values of Lp(a) decreased from 36.5 to 8.4 mg/dl (p < 0.0002) and total cholesterol from 254.5 to 208.0 mg/dl (p < 0.0001). The small number of patients does not permit any definitive conclusion on effectiveness to be drawn, but the results indicate further randomized studies might prove worthwhile. |
| Gemfibrozil for the secondary prevention of coronary heart disease in men with low levels of high-density lipoprotein cholesterol. Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial Study Group Rubins, H. B., S. J. Robins, et al. (1999), N Engl J Med 341(6): 410-8. Abstract: BACKGROUND: Although it is generally accepted that lowering elevated serum levels of low-density lipoprotein (LDL) cholesterol in patients with coronary heart disease is beneficial, there are few data to guide decisions about therapy for patients whose primary lipid abnormality is a low level of high-density lipoprotein (HDL) cholesterol. METHODS: We conducted a double-blind trial comparing gemfibrozil (1200 mg per day) with placebo in 2531 men with coronary heart disease, an HDL cholesterol level of 40 mg per deciliter (1.0 mmol per liter) or less, and an LDL cholesterol level of 140 mg per deciliter (3.6 mmol per liter) or less. The primary study outcome was nonfatal myocardial infarction or death from coronary causes. RESULTS: The median follow-up was 5.1 years. At one year, the mean HDL cholesterol level was 6 percent higher, the mean triglyceride level was 31 percent lower, and the mean total cholesterol level was 4 percent lower in the gemfibrozil group than in the placebo group. LDL cholesterol levels did not differ significantly between the groups. A primary event occurred in 275 of the 1267 patients assigned to placebo (21.7 percent) and in 219 of the 1264 patients assigned to gemfibrozil (17.3 percent). The overall reduction in the risk of an event was 4.4 percentage points, and the reduction in relative risk was 22 percent (95 percent confidence interval, 7 to 35 percent; P=0.006). We observed a 24 percent reduction in the combined outcome of death from coronary heart disease, nonfatal myocardial infarction, and stroke (P< 0.001). There were no significant differences in the rates of coronary revascularization, hospitalization for unstable angina, death from any cause, and cancer. CONCLUSIONS: Gemfibrozil therapy resulted in a significant reduction in the risk of major cardiovascular events in patients with coronary disease whose primary lipid abnormality was a low HDL cholesterol level. The findings suggest that the rate of coronary events is reduced by raising HDL cholesterol levels and lowering levels of triglycerides without lowering LDL cholesterol levels. |
| Gemfibrozil increases apolipoprotein A-I and cholesterol concentrations in human peripheral lymph Reichl, D., N. E. Miller, et al. (1993), Eur J Clin Invest 23(4): 254-8. Abstract: Peripheral lymph lipoproteins were studied in four hyperlipidaemic men before and after 6 weeks of treatment with gemfibrozil, a drug which is known to increase the fractional catabolic rate of very low density lipoproteins (VLDL) by raising lipoprotein lipase activity in peripheral tissues. Decreases in plasma triglycerides of 18-60% (mean, 45%) were accompanied by increases in lymph apolipoprotein (apo) A-I concentration of 30-108% (mean, 66%; P < 0.01), and in lymph cholesterol concentration of 35-100% (mean, 59%; P < 0.05). The additional lymph cholesterol was distributed over a broad range of lipoprotein particle sizes. Effects on plasma apo A-I concentration (mean, +7%) and plasma total cholesterol concentration (-7%) were not statistically significant. No changes were observed in four untreated control subjects. These findings are compatible with the hypothesis that lipolysis of VLDL at the blood-endothelium interface increases the transfer of apo A-I from plasma to interstitial fluids, and thereby promotes cholesterol efflux from cells. |
| Gemfibrozil prevents major coronary events by increasing HDL-cholesterol and more Doggrell, S. A. (2001), Expert Opin Pharmacother 2(7): 1187-9. Abstract: A low concentration of plasma high-density lipoprotein (HDL)-cholesterol is a major risk factor for coronary heart disease (CHD). Gemfibrozil reduces the number of CHD events by 22% in 5 years. This marked beneficial effect can only partly be explained by the ability of gemfibrozil to increase HDL-cholesterol. Recently gemfibrozil has been shown to activate peroxisome proliferator-activated nuclear receptors. This activation leads to the increase in HDL-cholesterol and to a decrease in vascular wall inflammation and other changes in vascular function. These vascular effects of gemfibrozil may contribute to the beneficial effects in CHD. |
| Gemfibrozil reduces non-high-density lipoprotein cholesterol in exogenously hypercholesterolemic (ExHC) rats fed a high-cholesterol diet Nagao, K., S. Yoshida, et al. (1998), Comp Biochem Physiol B Biochem Mol Biol 120(3): 579-86. Abstract: Gemfibrozil is a widely used drug prescribed to elevate serum high-density lipoprotein (HDL) cholesterol levels and lower triacylglycerols. The present study was done to determine if the drug would alleviate hypercholesterolemia in exogenously hypercholesterolemic (ExHC) rats. In the drug-treated ExHC rats, the serum non-HDL cholesterol levels were lowered and the ratio of the non HDL cholesterol to serum triacylglycerols was decreased to the extent seen in the drug-treated SD rats. Liver cholesterol and triacylglycerols were lowered in the drug-treated rats. There was also an increase in fecal excretion of neutral sterols and bile acids, particularly chenodeoxycholic and beta-muricholic acids. The drug elevated cholesterol 7 alpha-hydroxylase activity and mRNA abundance and acyl-CoA cholesterol acyltransferase activity in the liver, but did not influence low-density lipoprotein receptor mRNA level in the liver. Thus, gemfibrozil is effective in alleviating hypercholesterolemia in exogenously hypercholesterolemic rats, by partitioning hepatic cholesterol into biliary excretion. |
| Gemfibrozil treatment of the high triglyceride-low high-density lipoprotein cholesterol trait in men with established atherosclerosis Knipscheer, H. C., M. T. Nurmohamed, et al. (1994), J Intern Med 236(4): 377-84. Abstract: OBJECTIVE. To study the short-term efficacy, tolerability and safety of the treatment with gemfibrozil 600 mg twice daily or placebo in male patients with established atherosclerosis, with a lipid profile matching the 'high triglyceride-low high-density lipoprotein (HDL) cholesterol trait'. DESIGN. Double-blind randomized placebo controlled prospective trial. SETTING. Amsterdam Lipid Research Clinic at the Academic Medical Centre of the University of Amsterdam and the Slotervaart Training Hospital affiliated to the University of Amsterdam, Amsterdam, the Netherlands. SUBJECTS. Thirty-five male patients, age 30-70, with established atherosclerosis and the high triglyceride-low HDL cholesterol trait. MAIN OUTCOME MEASURES. Plasma total cholesterol, triglycerides, lipoproteins, apolipoproteins A1 and B100, clinical and laboratory safety parameters. RESULTS. Seventeen patients in the gemfibrozil group and 16 patients in the placebo group completed the study period. Compliance was considered adequate. Mean (+/- standard deviation) plasma HDL cholesterol levels increased 20.3% (+/- 12.22) from 0.82 to 0.99 mmol L-1 in the gemfibrozil group against 9.9% (+/- 18.31) from 0.79 to 0.87 mmol L-1 in the placebo group (P = 0.001). Mean plasma triglyceride level fell 49.5% (+/- 14.27) from 3.65 to 1.82 mmol L-1 in the gemfibrozil group against an increase of 13.6% (+/- 40.31) from 3.62 to 4.01 mmol L-1 in the placebo group (P < 0.001). Although plasma HDL cholesterol and triglyceride levels improved in all patients, normalization of these lipoproteins was only observed in approximately half of them. Plasma total and low-density lipoprotein (LDL) cholesterol levels, as well as plasma levels of apolipoprotein (apo) A1, B100 and lipoprotein Lp(a), did not show significant alterations compared to the placebo. All safety parameters were comparable between the two groups and remained within the reference limits. Gemfibrozil was well tolerated during treatment. Minor inconveniences were equally distributed between the two treatment groups. CONCLUSIONS. Gemfibrozil is an effective and safe drug in patients with coronary heart disease (CHD) and the high triglyceride-low HDL cholesterol trait. |
| Gender alters the high-density lipoprotein cholesterol response to cardiac rehabilitation Savage, P. D., M. Brochu, et al. (2004), J Cardiopulm Rehabil 24(4): 248-54; quiz 255-6. Abstract: PURPOSE: A reduced level of high-density lipoprotein cholesterol (HDL-C) is a powerful independent risk factor for the development and progression of coronary heart disease. This study assessed the effects of cardiac rehabilitation exercise training on HDL-C and other lipid subfractions, giving close attention to the role of gender and baseline values. METHODS: The study population consisted of 340 patients with coronary heart disease who enrolled in outpatient cardiac rehabilitation and completed 36 sessions of exercise over a 12-week period. With the National Cholesterol Education Panel ATP III guidelines used to create categories of HDL-C, patients were stratified at baseline into four subgroups: (1) males with high HDL-C, (2) males with low HDL-C, (3) women with high HDL-C, and (4) women with low HDL-C. RESULTS: Overall, women experienced a significantly greater improvement in HDL-C after exercise training than men (14% vs 7.1%; P <.0001). Among the patients with a high HDL-C at baseline, the women increased HDL-C by 8.4%, whereas there was no change (0.9%) in the men (P <.001 between groups). Additionally, the women with low HDL-C experienced a significantly greater improvement than the men (15.3% vs 11.5%, P <.03). CONCLUSIONS: The study results demonstrate that women experience a greater improvement in HDL-C with cardiac rehabilitation than men despite similar changes in fitness and body composition. Women, regardless of baseline HDL-C, demonstrated improvements in HDL-C, whereas only men with low HDL-C experienced an increase in HDL-C. These results describe a differing impact of cardiac rehabilitation on changes in HDL-C based on gender. Clinicians should consider the impact of gender when assessing an individual's risk factor goals and therapeutic options. |
| Gender and employment grade differences in blood cholesterol, apolipoproteins and haemostatic factors in the Whitehall II study Brunner, E. J., M. G. Marmot, et al. (1993), Atherosclerosis 102(2): 195-207. Abstract: In the first Whitehall study, plasma cholesterol was a strong predictor of coronary heart disease (CHD) but it showed a positive association with grade of employment: the higher the grade the higher the level. Because it could not explain the higher rate of CHD in lower employment grades, further investigation of biochemical CHD risk factors has been conducted with data from the baseline examination of the Whitehall II cohort in 1985-88. These data also allow investigation of gender differences and the effect of menopause. Serum cholesterol (6860 men and 3374 women) and apolipoproteins A-I and B (apo AI and apo B) were measured in those aged 35-55 working in the London offices of twenty Civil Service departments. Plasma fibrinogen and factor VII were determined in 45-55 year olds. The apo B/apo AI ratio (95% confidence interval) after age adjustment is lowest in premenopausal women: 0.557 (0.549-0.565), intermediate in postmenopausal women: 0.601 (0.589-0.613) and highest in men: 0.703 (0.698-0.709). After age adjustment fibrinogen is higher in postmenopausal (2.90 (2.85-2.95) g/l) than in premenopausal women (2.78 (2.71-2.84) g/l), who have higher levels than men (2.64 (2.62-2.67) g/l). A positive association with employment grade is seen for apo AI and a negative association is seen for fibrinogen, apo B (women only) and the apo B/apo AI ratio, after age adjustment. These patterns are consistent with the higher rates of CHD in lower grades. Cholesterol and factor VII show no gradient with our sensitive measure of social position. After adjusting for the effects of smoking rates, alcohol consumption, exercise and dietary pattern, as well as age, ethnicity, body mass index and report of symptoms, the regression coefficient for apo AI on employment grade is reduced by 43% in men and 70% in women. Corresponding reductions for fibrinogen are 53% and 65%. These attenuations suggest that a considerable part of the social gradients in apo AI and fibrinogen are explained by variations in health related behaviours. The remaining gradients may represent effects independent of these behaviours. |
| Gender and hormonal status affect the regulation of hepatic cholesterol 7alpha-hydroxylase activity and mRNA abundance by dietary soluble fiber in the guinea pig Roy, S., H. C. Freake, et al. (2002), Atherosclerosis 163(1): 29-37. Abstract: Dietary soluble fiber (SF) consistently lowers plasma LDL cholesterol (LDL-C) concentrations, however, secondary mechanisms governing this reduction are not completely defined. Moreover, these mechanisms appear to differ with gender. Male, female and ovariectomized (to mimic menopause) guinea pigs were used to assess effects of gender, hormonal status and SF on activity and expression of hepatic cholesterol 7alpha-hydroxylase (CYP7). Diets were identical except for fiber source (control 10% cellulose, SF 5% psyllium/5% pectin). SF intake resulted in 44% lower plasma total cholesterol, 51% lower plasma LDL-C and 22% lower plasma triacylglycerol (TAG) concentrations. However, ovariectomized guinea pigs fed either the control or SF diets, had the highest plasma LDL-C and TAG levels (P<0.01). SF altered hepatic cholesterol metabolism by effectively reducing hepatic free cholesterol, TAG and microsomal free cholesterol, while activity of CYP7, the rate-limiting enzyme of cholesterol catabolism, was up-regulated. Hepatic CYP7 mRNA abundance paralleled the increase in enzyme activity. Ovariectomized guinea pigs had lowest activity and expression of hepatic CYP7 even after intervention with SF. These results suggest that induction of hepatic CYP7 activity may account, in large part, for the hypocholesterolemic effect of SF. Gender and hormonal status influence metabolic responses to dietary SF with estrogen deprivation leading to the most detrimental lipid profile. |
| Gender differences in adults' knowledge about fat and cholesterol Auld, G. W., C. Achterberg, et al. (1991), J Am Diet Assoc 91(11): 1391-7. Abstract: Cognitive learning theories suggest that an individual's prior knowledge is a major factor for determining what can be learned. The objectives of this study were to compare the organization of knowledge about fat and cholesterol in adult, middle-class men and women and changes in that knowledge after reading an educational bulletin. Forty men and 48 women participated in two semistructured interviews to assess their knowledge; half received a US Department of Agriculture bulletin on fat and cholesterol at the end of the first interview. Concept maps (two-dimensional representations of an individual's cognitive knowledge structure) were made from the interview transcripts to assess knowledge organization. Both genders had limited knowledge, scoring less than 25% of the maximum possible score at interview 1. Overall, known and not known concepts were similar in men and women; however, women had slightly more integrated knowledge and more misconceptions than men. Both groups receiving the bulletin made significant gains in knowledge at interview 2, but knowledge gains were twice as great in men as in women. Our findings indicate that practitioners need not create separate materials about fat and cholesterol for middle-class men and women. |
| Gender differences in response to a hypercholesterolemic diet in hamsters: effects on plasma lipoprotein cholesterol concentrations and early aortic atherosclerosis Wilson, T. A., R. J. Nicolosi, et al. (1999), Atherosclerosis 146(1): 83-91. Abstract: Gender is a strong predictor of coronary heart disease (CHD) susceptibility and reports indicate that males are more likely to develop CHD compared to age-matched premenopausal females. To test whether similar gender differences exist in hamsters, 16 male and 16 female F1B Golden Syrian hamsters, aged 10 weeks, were fed a hypercholesterolemic nonpurified diet (HCD) containing 10% coconut oil and 0.05% cholesterol for 12 weeks. Plasma lipid and lipoprotein cholesterol concentrations, LDL oxidative susceptibility, LDL tocopherol concentrations, LDL fatty acid composition, LDL particle size, plasma estradiol and testosterone concentrations, and early aortic atherosclerosis were analyzed. Female hamsters had significantly lower plasma total cholesterol and nonhigh-density lipoprotein cholesterol (nonHDL-C) and greater high-density lipoprotein cholesterol (HDL-C) concentrations compared to male hamsters (-15, -33, and 33%; respectively). Female hamsters had significantly greater LDL particle size (4%), LDL 22:6 (21%) fatty acid, and rate of LDL oxidation (34%) compared to male hamsters. Female hamsters had a significantly higher concentration of plasma estradiol (49%) compared to male hamsters. Female hamsters also had significantly less early aortic atherosclerosis compared to male hamsters (-77%). In female hamsters, aortic fatty streak formation was significantly associated with plasma nonHDL-C (r = 0.76, P<0.0007), LDL particle size (r = -0.66, P<0.005), plasma TC (r = 0.68. P<0.004), and lag phase of LDL oxidation (r = 0.84. P<0.02). In male hamsters, aortic fatty streak formation was significantly associated with plasma nonHDL-C (r = 0.52, P<0.04), plasma TC (r = 0.55, P<0.03), plasma TG (r = 0.79, P<0.0003), and LDL 22:6 (r = -0.78, P<0.03) with no association with any measures of LDL oxidation susceptibility. This study demonstrates that female hamsters have an improved plasma lipoprotein cholesterol profile, larger LDL particle size, and less early aortic atherosclerosis compared to male hamsters fed the same HCD. |
| Gender effects of tall oil versus soybean phytosterols as cholesterol-lowering agents in hamsters Ntanios, F. Y., D. E. MacDougall, et al. (1998), Can J Physiol Pharmacol 76(7-8): 780-7. Abstract: To examine the effect of gender on the mechanisms of action of phytosterols extracted from tall oil (TO) and soybean (SB) on cholesterol and phytosterol metabolism, male and female hamsters were fed cholesterol-enriched diets containing 0.5 or 1% (w/w) TO or SB phytosterols for 90 days. Plasma lipoprotein cholesterol profile and tissue phytosterol and cholesterol biosynthesis levels were determined. Mean plasma total-cholesterol level in females fed 1% (w/w) SB was reduced (p<0.05) by 44%, while in males it was lowered (p<0.05) by 25% compared with their respective controls. Moreover, mean plasma total-cholesterol level was reduced (p<0.05) in male hamsters by -31% and female hamsters by -32% when fed 1% (w/w) TO. Cholesterol biosynthesis was higher (p<0.05) by twofold in groups fed TO at 0.5 and 1% (w/w) concentrations, compared with SB. Hamsters fed TO at 0.5 and 1% (w/w) levels also had higher (p<0.05) hepatic and enterocytic campesterol contents than SB-fed animals. These findings demonstrate gender differences in cholesterol metabolism in TO- and SB-fed hamsters. The results suggest that TO, conversely to SB phytosterol, is a more effective cholesterol-lowering agent in male, but not as much in female, hamsters, over a feeding period of 90 days. |
| Gender gap in aortic cholesterol accumulation in cholesterol-clamped rabbits: role of the endothelium and mononuclear-endothelial cell interaction Holm, P., H. L. Andersen, et al. (1998), Circulation 98(24): 2731-7. Abstract: BACKGROUND: The purpose of the present study was to investigate plasma lipid-independent mechanisms for the sex difference in the development of atherosclerosis. METHODS AND RESULTS: In the first experiment, 20 male and 20 female rabbits were balloon-injured in the middle thoracic aorta and maintained at the same plasma cholesterol level of approximately 25 mmol/L by use of individualized cholesterol feeding for 13 weeks. In the undamaged aorta, female rabbits had accumulated less than half the amount of cholesterol found in male rabbits (P<0.05). In the balloon-injured aorta, cholesterol accumulation was 3- to 4-fold higher than in the undamaged aorta, with no difference between groups. When cholesterol accumulation data for the balloon-injured aorta were separately assessed for blue (deendothelialized) and white (reendothelialized) tissue, blue tissue surprisingly revealed a reverse gender gap, ie, a significantly higher accumulation of cholesterol in females than in males (P<0.05). White tissue, which constituted the majority of the balloon-injured area, showed no difference in aortic cholesterol accumulation between groups. In the second experiment, 6 male and 6 female rabbits were fed standard rabbit pellets and 6 male and 6 female rabbits were fed a 0.5% cholesterol-enriched chow for 2 weeks. Mononuclear cell binding was 5-fold higher in aortic segments from hypercholesterolemic than from normocholesterolemic rabbits (P<0. 001). In hypercholesterolemic rabbits, cell binding was significantly lower in female than in male rabbits (P<0.05) and showed higher values in atherosclerosis-prone regions. These differences were not found in normocholesterolemic animals. CONCLUSIONS: The present results suggest that female atheroprotection is independent of sex differences in plasma cholesterol but vitally dependent on the state of the arterial endothelium and involves mononuclear-endothelial cell adhesion as an early step. |
| Gender may affect the action of garlic oil on plasma cholesterol and glucose levels of normal subjects Zhang, X. H., D. Lowe, et al. (2001), J Nutr 131(5): 1471-8. Abstract: Early trials of garlic preparations on blood lipids mainly supported a lipid-lowering effect, whereas later well-designed garlic tablet trials were mainly entirely null. However, enteric simulation tests suggest that this discordance may result from ineffective delivery of bioactive agents from the brands of garlic powder (GP) and cyclodextrin-bound garlic oil (GO) tablets tested in some recent negative trials. In contrast, enteric simulation tests show that the preformed bioactive agents present in "traditional" gelatin capsules of GO are efficiently released, although such capsules have rarely been investigated in lipid-lowering trials. It was hypothesized that gelatin capsules of GO given to normal subjects would improve specified coronary heart disease risk factors. Effects of a GP preparation were also investigated. Subjects (n = 51; men and women, mean age 27 y) were randomly assigned to receive either 8.2 mg/d of GO (allyl sulfides) or placebo for 11 wk. Another 27 subjects received garlic powder (GP) of similar biopotential (7.8 mg allicin/d). Outcome measures were 95% confidence intervals (CI) between GO and placebo groups for differences between baseline and subsequent sample times. Men and women combined showed no significant differences save for an improved total antioxidant capacity at 6 wk (P = 0.01). Hence, no benefit from GO after 11 wk is one plausible conclusion. However, there were significant differences in effect of GO between men and women for HDL cholesterol (HDL-C) (P = 0.004) and total cholesterol (TC)/HDL-C (P = 0.003). Women showed favorable effects in terms of CHD risk factors (i.e., increases in HDL-C and reductions in TC/HDL-C), whereas men had small adverse effects. There was a significant difference in the GO effect for glucose (P = 0.006), with a reduction seen for men and an increase for women. The gender effects were unexpected and such analyses were not planned in advance. Confirmation of these findings with larger numbers of subjects would have importance for the use of garlic against CHD and for the design of future garlic studies. |
| Gender-related differences in bile acid and sterol metabolism in outbred CD-1 mice fed low- and high-cholesterol diets Turley, S. D., M. Schwarz, et al. (1998), Hepatology 28(4): 1088-94. Abstract: These studies were undertaken to determine whether in young adult outbred CD-1 mice there were any gender-related differences in basal bile acid metabolism that might be important in determining how males and females in this species responded to a dietary cholesterol challenge. When fed a plain cereal-based rodent diet without added cholesterol, 3-month-old females, compared with age-matched males, manifested a significantly larger bile acid pool (89.1 vs. 54.1 micromol/100 g body weight), a higher rate of fecal bile acid excretion (13.6 vs. 8.5 micromol/d/100 g body weight), a more efficient level of intestinal cholesterol absorption (41.1% vs. 25. 3%), and a lower rate of hepatic sterol synthesis (338 vs. 847 nmol/h/g). Similar results were found in C57BL/6 and 129Sv inbred mice. In matching groups of CD-1 mice fed a diet containing 1% cholesterol for 21 days, hepatic cholesterol levels increased much more in the females (from 2.4 to 9.1 mg/g) than in the males (from 2. 1 to 5.2 mg/g). This occurred even though the level of stimulation of cholesterol 7-hydroxylase activity in the females (79%) exceeded that in the males (55%), as did the magnitude of the increase in fecal bile acid excretion (females: 262% vs. males: 218%). However, in both sexes, bile acid pool size expanded only modestly and by a comparable degree (females: 19% vs. males: 26%) so that in the cholesterol-fed groups, the pool remained substantially larger in the females than in the males (102.3 vs. 67.6 micromol/100 g body weight). Together, these data demonstrate that while male and female CD-1 mice do not differ qualitatively in the way cholesterol feeding changes their bile acid metabolism, the inherently larger bile acid pool in the female likely facilitates the delivery of significantly more dietary cholesterol to the liver than is the case in males, thereby resulting in higher steady-state hepatic cholesterol levels. |
| Gender-specific correlation of platelet ionized magnesium and serum low-density-lipoprotein cholesterol concentrations in apparently healthy subjects Niemela, J. E., G. Csako, et al. (1997), J Lab Clin Med 129(1): 89-96. Abstract: We previously found an inverse correlation between platelet ionized magnesium concentration ((Mg2+)i) and serum total cholesterol concentration in normal male but not female subjects. In the present study, we determined the platelet (Mg2+)i by using a fluorescent ionized magnesium (Mg2+) indicator, FURAPTRA, and measured the serum concentrations of the following: total cholesterol; very-low-density lipoprotein cholesterol (VLDL-C); low-density lipoprotein cholesterol (LDL-C); high-density lipoprotein cholesterol (HDL-C); antioxidized low-density lipoprotein (LDL) autoantibodies; lipoprotein(a); apolipoproteins A-I (apo A-I) and B (apo B); triglycerides; estradiol-17 (E2); ceruloplasmin (Cp); and selected electrolytes, including total and ionized magnesium and calcium and total protein and albumin. In men, but not in women, platelet (Mg2+)i significantly inversely correlated with serum total cholesterol (r = -0.52, p < 0.02), LDL-C (r = -0.54, p < 0.009 by a "direct" method; r = -0.40, p < 0.05 by an electrophoretic method), and apo B (r = -0.42, p < 0.04). We found no significant correlations between platelet (Mg2+)i and any other variables, including serum total and ionized magnesium, antioxidized LDL autoantibodies, Cp, and E2. We speculate that decreased platelet (Mg2+)i is a possible marker for platelet membrane alterations that may affect platelet involvement in thrombosis and atherogenesis. |
| Gender-specific effects of estrogen receptor alpha gene haplotype on high-density lipoprotein cholesterol response to atorvastatin: interaction with apolipoprotein AI gene polymorphism Kajinami, K., M. E. Brousseau, et al. (2005), Atherosclerosis 178(2): 331-8. Abstract: Statins can modestly raise the levels of HDL cholesterol and apolipoprotein A-I (APOA1). Recently, associations between polymorphisms in the estrogen receptor alpha (ESR1) and the HDL cholesterol response to hormone replacement therapy were reported. To test the hypothesis that common polymorphisms in ESR1 and APOA1 genes are associated with the response to statin therapy, two ESR1 (PvuII and XbaI) and two APOA1 (G-75A and +83) polymorphisms were examined in 338 hypercholesterolemic patients treated with atorvastatin 10mg. The ESR1 PvuII-XbaI+ haplotype was significantly, and independently, associated with a greater response of HDL raising in women (+13% versus +7%, p=0.010) but not in men (+9% versus +7%, p=0.248). Effects of the APOA1+83 variant allele on HDL cholesterol response also differed significantly by gender (p=0.012). The APOA1+83 variant allele was associated with higher basal LDL cholesterol levels in men as well, but not in women. Finally, significant interactions were observed between the ESR1 PvuII-XbaI+ haplotype and the APOA1+83 variant allele regarding both HDL (p=0.042) and LDL (p=0.031) cholesterol responses. In conclusion, the ESR1 haplotype was associated with a greater HDL-raising to atorvastatin in a gender-specific manner, and the interactions between ESR1 and APOA1 genotypes regarding HDL and LDL cholesterol response were also gender specific. |
| Gene by smoking interaction: evidence for effects on low-density lipoprotein size and plasma levels of triglyceride and high-density lipoprotein cholesterol Czerwinski, S. A., M. C. Mahaney, et al. (2004), Hum Biol 76(6): 863-76. Abstract: We seek to determine whether significant gene x smoking interaction effects exist on plasma triglyceride (TG) levels, HDL cholesterol (HDL-C) level, and median LDL particle diameter (LDL-MPD) in Mexican American families enrolled in the San Antonio Family Heart Study. The sample consisted of 1,392 individuals distributed in 42 extended pedigrees, ranging in age from 16 years to 92 years. Separate quantitative genetic analyses were carried out for TG and HDL-C level and LDL-MPD using a maximum-likelihood-based variance decomposition approach while simultaneously adjusting for age and sex. Initial heritability estimates demonstrated significant (p < 0.001) additive genetic contributions to all three traits (h2 range 0.50 - 0.54). To test for a gene x smoking interaction, we included in the model additional smoking-status-specific variance terms and a genetic correlation term between smokers and nonsmokers. Comparisons of nested models revealed significant evidence (p < 0.01) for a gene X smoking interaction effect on TG level and LDL-MPD and possible evidence for an effect on HDL-C level. These results indicate that the gene or suite of genes regulating each of these phenotypes is likely the same in smokers and non-smokers but that smoking may alter the expression of genes, particularly those influencing TG level and LDL-MPD. |
| Gene delivery by dendrimers operates via a cholesterol dependent pathway Manunta, M., P. H. Tan, et al. (2004), Nucleic Acids Res 32(9): 2730-9. Abstract: Understanding the cellular uptake and intracellular trafficking of dendrimer-DNA complexes is an important prerequisite for improving the transfection efficiency of non-viral vector-mediated gene delivery. Dendrimers are synthetic polymers used for gene transfer. Although these cationic molecules show promise as versatile DNA carriers, very little is known about the mechanism of gene delivery. This paper investigates how the uptake occurs, using an endothelial cell line as model, and evaluates whether the internalization of dendriplexes takes place randomly on the cell surface or at preferential sites such as membrane rafts. Following extraction of plasma membrane cholesterol, the transfection efficiency of the gene delivered by dendrimers was drastically decreased. Replenishment of membrane cholesterol restored the gene expression. The binding and especially internalization of dendriplexes was strongly reduced by cholesterol depletion before transfection. However, cholesterol removal after transfection did not inhibit expression of the delivered gene. Fluorescent dendriplexes co-localize with the ganglioside GM1 present into membrane rafts in both an immunoprecipitation assay and confocal microscopy studies. These data strongly suggest that membrane cholesterol and raft integrity are physiologically relevant for the cellular uptake of dendrimer-DNA complexes. Hence these findings provide evidence that membrane rafts are important for the internalization of non-viral vectors in gene therapy. |
| Gene dose effect of the APOE-epsilon4 allele on plasma HDL cholesterol level in patients with Alzheimer's disease Hoshino, T., K. Kamino, et al. (2002), Neurobiol Aging 23(1): 41-5. Abstract: It has been reported that decreased serum high density lipoprotein (HDL) cholesterol level is related with severity of Alzheimer's disease (AD). Here, 82 patients with AD and 40 non-demented individuals were examined to determine how the APOE-epsilon4 allele modifies plasma cholesterol fractions. In adjusting for age, sex and plasma albumin level, plasma HDL cholesterol level was inversely correlated with the APOE-epsilon4 dose only in the patients (P = 0.0048), while plasma low density lipoprotein (LDL) cholesterol level tended to be correlated with the APOE-epsilon4 dose in both groups, although this was not significant. The ratio of LDL to HDL cholesterol in the patients showed a similar correlation with the APOE-epsilon4 dose to that in the controls, and this correlation was evident (P = 0.0069) after putting all subjects into one group. However, neither HDL nor LDL cholesterol levels showed significant differences between the groups. These results indicated that the APOE-epsilon4 dose affects the composition of plasma cholesterol, and suggested that the genetic effect on plasma lipid metabolism could be distinctive in patients with AD. |