Cholesterol Journal Articles

Record 7941 to 7960

Intravenous injection of rabbit apolipoprotein A-I inhibits the progression of atherosclerosis in cholesterol-fed rabbits
Miyazaki, A., S. Sakuma, et al. (1995), Arterioscler Thromb Vasc Biol 15(11): 1882-8.
Abstract: The effects of intravenous injection of purified rabbit apoA-I on the progression of aortic atherosclerosis in cholesterol-fed rabbits were examined. In experiment 1, 28 rabbits were equally divided into groups A and B and fed a 0.5% cholesterol diet for 90 days. For the last 30 days, group B received 40 mg apoA-I every week. The fatty streak lesions in group B (23.9 +/- 15.6%) were significantly suppressed compared with those in group A (46.0 +/- 24.9%) (P <.05). In experiment 2, 33 rabbits were divided into four groups (8 or 9 rabbits per group) and fed a 0.5% cholesterol diet. Group A was killed on day 105, while groups B, C, and D were maintained for an additional 60 days on a normal diet, during which time groups C and D received 1 mg apoA-I every other day or 40 mg apoA-I every week, respectively. The lesions in group C (70.2 +/- 15.4%) and group D (65.7 +/- 20.0%) were significantly suppressed compared with those in group B (86.2 +/- 13.7%) (P <.05) but were not reduced to the level of group A (50.0 +/- 22.9%). Although apparent regression was not observed under these conditions, the present study provided the first evidence for the antiatherogenic effect of homologous and apoA-I on the progression of atherosclerosis in cholesterol-fed rabbits.

Introducing a new component of the metabolic syndrome: low cholesterol absorption
Simonen, P., H. Gylling, et al. (2000), Am J Clin Nutr 72(1): 82-8.
Abstract: BACKGROUND: Weight reduction is the recommended treatment of obese type 2 diabetes, but the effects of weight reduction on cholesterol metabolism are poorly understood. OBJECTIVE: We investigated glucose, cholesterol, and lipoprotein metabolism at baseline and 2 y after weight reduction in obese patients with type 2 diabetes consuming an isoenergetic diet. DESIGN: Sixteen subjects were randomly chosen to consume a very-low-energy or low-energy diet for 3 mo, after which they consumed a weight-maintenance diet for up to 2 y. Cholesterol absorption and metabolism, LDL and HDL kinetics, and variables of glucose metabolism were studied at baseline and 2 y. RESULTS: Baseline serum sex hormone binding globulin (SHBG) was significantly related to cholesterol absorption efficiency, and serum glucose and insulin concentrations were associated with cholesterol synthesis. After 2 y, body weight was reduced by 6 +/- 1 kg (P < 0.01), body mass index by 6% (P < 0.05), and blood glucose by 14% (P < 0.01); the ratio of serum SHBG to insulin increased by 66% (P < 0.05). Serum and VLDL, LDL, and HDL triacylglycerol were significantly reduced by 13-24%. Despite unchanged serum concentrations of cholesterol, cholesterol absorption efficiency and the ratio of serum plant sterols to cholesterol-indicators of cholesterol absorption-increased by 28% (P < 0.01) and 20-31% (P < 0. 05 for both), respectively; the fractional removal of LDL apolipoprotein B decreased. Fecal excretion of cholesterol as neutral sterols decreased significantly by 11%. Changes in body weight were significantly negatively correlated with changes in ratios of cholesterol to serum plant sterols and cholestanol. CONCLUSIONS: Baseline cholesterol absorption and synthesis were related to respective serum SHBG, glucose, and insulin values. Weight reduction increased cholesterol absorption and improved variables of glucose metabolism. These results suggest that low cholesterol absorption and high synthesis may be part of the insulin resistance syndrome.

Inulin and oligofructose do not influence the absorption of cholesterol, or the excretion of cholesterol, Ca, Mg, Zn, Fe, or bile acids but increases energy excretion in ileostomy subjects
Ellegard, L., H. Andersson, et al. (1997), Eur J Clin Nutr 51(1): 1-5.
Abstract: OBJECTIVE: To investigate the effects of inulin and oligofructose on cholesterol absorption and excretion of cholesterol, bile acids, energy, nitrogen and minerals in man. DESIGN: Double-blind cross-over study. SETTING: Metabolic kitchen with policlinic visits, Sahlgrenska Hospital, Goteborg, Sweden. SUBJECTS: Patients with conventional ileostomy because of ulcerative colitis. INTERVENTIONS: 7 g of inulin, 17 g of oligofructose and 7 g of sucrose were added to a controlled diet during three experimental periods of three days each. Ileostomy effluents were collected and analysed. Differences between experimental and control diet were investigated with the Wilcoxon's sign and values test. RESULTS: Inulin and oligofructose were recovered in the ileostomy effluent to 88% (95% CI, 76-100%) and 89% (64-114%) respectively. Dry solid excretion increased by 14.4 g (11.3-17.5) on inulin, and by 14.7 g (13.0-16.4 g) on oligofructose and energy excretion increased 245 kJ (190-307 kJ) on inulin and 230 kJ (214-315 kJ) on oligofructose compared to control diet (P < 0.05). Cholesterol absorption, excretion of cholesterol, bile acids, nitrogen, fat, calcium, magnesium, zinc and iron were not affected by inulin and oligofructose. CONCLUSIONS: Inulin and oligofructose are not digested in the small intestine. They do not affect mineral excretion and hence hardly mineral absorption. They do not increase fat or nitrogen excretion from the small intestine. Any physiological effect of inulin and oligofructose is probably mediated through other mechanisms than altered excretion from the small intestine.

Invasive middle ear cholesterol granuloma involving the basal turn of the cochlea with profound sensorineural hearing loss
Murugasu, E., T. T. Yong, et al. (2004), Otol Neurotol 25(3): 231-5.
Abstract: STUDY DESIGN: A retrospective surgical case review. SETTING: A tertiary-care, university teaching hospital. PATIENTS: The authors describe a unique case operated on for a middle ear cholesterol granuloma, which had invaded the cochlea and vestibule causing profound sensorineural deafness. INTERVENTIONS: Extended radical mastoidectomy and labyrinthectomy with musculofascial seal. RESULTS: Successful postoperative outcome with no recurrence seen after 2 years of follow up. CONCLUSION: To the authors' knowledge, this is the first reported case of a primary middle ear cholesterol granuloma with direct invasion into the cochlea. Such invasion of the otic capsule by cholesterol granulomas is rare and presents a diagnostic challenge to the attending otologist and radiologist. Salient points of the case history, pathogenesis, imaging studies, histopathology, and management are presented with a review of the current literature.

Inverse association between birth weight, birth length and serum total cholesterol in adulthood
Ziegler, B., S. P. Johnsen, et al. (2000), Scand Cardiovasc J 34(6): 584-8.
Abstract: OBJECTIVES: To investigate whether impaired fetal growth, measured by low birth weight and short birth length, is linked with raised levels of serum lipids and increased risk and mortality of coronary heart disease. DESIGN: The association between birth length, birth weight, Ponderal Index and total serum cholesterol was examined in 545 Danish men and women aged 31 to 51 years who participated in the Ebeltoft Health Promotion Project in Denmark. RESULTS: No associations were found in women. For men, a negative association was found between birth weight and serum total cholesterol, with a fall in mean serum total cholesterol from 6.03 mmol/l at birth weight below 3300 g to 5.64 mmol/l at birth weight above 4000. A similar association was found between birth length and serum cholesterol, with a mean value of 6.23 mmol/l at birth length below 51 cm and a mean value of 5.56 mmol/l at birth length above 54 cm. No associations were found for Ponderal Index. Between 3% and 8% of the variance in serum total cholesterol could be explained by the statistical models used in this study. CONCLUSION: Our findings support the hypothesis of a negative association between birth weight, birth length and elevated serum cholesterol in adult life, but only in men.

Inverse association between plasma cholesterol and gallstone disease
Duque, M. X., S. Moran, et al. (1999), Arch Med Res 30(3): 190-7.
Abstract: BACKGROUND: The association between gallstone disease (gallstones or cholecystectomy) and plasma lipids was evaluated in 2,089 subjects who attended a private health care facility in Mexico City from August 1991 to August 1992. METHODS: All participants provided data on their sociodemographic status, non-insulin-dependent diabetes mellitus diagnoses, alcohol consumption, and smoking habits; women also gave data regarding their obstetric-gynecologic histories. Ultrasounds of the liver and biliary tract were performed. Cholesterol levels, high-density lipoproteins cholesterol, and triglyceride plasma concentration were determined. RESULTS: This study shows a strong inverse association between gallstone disease and plasma cholesterol concentration, with OR = 0.61 (95% CI = 0.42-0.89) in the category of 181-239 mg/dL, and OR = 0.49 (95% CI = 0.32-0.77) in the group of 240 mg/dL or more, when compared to 180 mg/dL or less, after adjusting for the following risk factors: gender, age, and body mass index. CONCLUSIONS: These results suggest an increment in the catabolic pool of cholesterol, reflected in lower levels of plasma cholesterol in subjects with gallstone disease.

Inverse association between serum total cholesterol and cancer mortality in Dutch civil servants
Schuit, A. J., C. E. Van Dijk, et al. (1993), Am J Epidemiol 137(9): 966-76.
Abstract: The association between serum total cholesterol and cancer mortality was investigated in a 28-year follow-up study of 3,091 Dutch civil servants aged 40-65 years and their spouses. After adjustment for age, body mass index, and smoking, an inverse association between serum total cholesterol and all-cancer mortality was observed in men during the first 15 years of follow-up, excluding the first 2 years: The multivariate rate ratio of those in the lowest cholesterol quintile compared with those in the highest quintile was 2.1 (95% confidence interval (Cl) 1.1-4.0); this association was accounted for mainly by gastrointestinal cancers (RR = 4.2, 95% Cl 1.4-12.9). For follow-up years 16-28, the multivariate rate ratio for all-cancer mortality was 0.8 (95% Cl 0.5-1.40. In women, no consistent association between serum total cholesterol and cancer was observed. After the first 5 years of follow-up were excluded, the significant inverse association in men still persisted. These results suggest that in this study population, low serum cholesterol seems not to be attributable to undetected cancer, but might be a risk factor for cancer mortality in men.

Inverse association of serum cholesterol with plasma insulin in the elderly. Cross-sectional and prospective analyses
Lindberg, O., R. S. Tilvis, et al. (1998), Aging (Milano) 10(2): 137-40.
Abstract: Cross-sectional studies have suggested that high plasma insulin is associated with relatively low levels of low density lipoprotein (LDL)-cholesterol. The present study was aimed at re-testing this association in a 70-year-old age cohort (N = 1023), and testing whether it could be caused by excessive mortality of hyperinsulinemic subjects with high LDL-cholesterol. A reverse U-shaped association between LDL-cholesterol and fasting plasma insulin was confirmed. LDL-cholesterol, HDL-cholesterol and total cholesterol were lowest in the highest insulin quarter. These associations remained after adjustment for diabetes, obesity and general health status. The combination of high LDL-cholesterol (> 4.25 mmol/L, 75th percentile) and high insulin (> 10 IU/L, 50th percentile) was not associated with excess 5-year mortality in this age cohort. Nor was it associated with excess mortality in four other elderly age cohorts (N = 1188), in which similar associations of cholesterol and insulin have been demonstrated. Thus, the inverse association of LDL-cholesterol with fasting insulin in the elderly is not caused by selective over mortality.

Inverse correlation between macrophage-colony stimulating factor, cholesterol and high density lipoprotein cholesterol in Kawasaki disease
Shikishima, Y., Y. Kawano, et al. (2001), Asian Pac J Allergy Immunol 19(2): 85-91.
Abstract: Kawasaki disease (KD) is a childhood-onset vascular disease. We assessed the concentrations of macrophage-colony stimulating factor (M-CSF) and those of lipids in sera from patients with KD. The M-CSF concentration in patients with acute-phase KD was 2,914+/-159 U/ml, significantly higher than that in control subjects with Infectious diseases (1,241+/-96 U/ml). The elevated levels of this cytokine in the acute phase fell to 1,319+/-138 U/ml in the convalescent phase. Total and high-density lipoprotein cholesterol concentrations in acute phase KD (113.8+/-8.4 and 21.5+/-2.3 mg/dl, respectively) were lower than in the infectious disease controls (195.8+/-7.0 and 62.5+/-1.8 mg/dl). The elevation of M-CSF correlated with the decrease of total and high-density lipoprotein cholesterol. Overproduction of macrophage-colony stimulating factor activates macrophages and monocytes and may disturb the lipid metabolism. Both effects could contribute to vasculitis in KD.

Inverse relationship between potassium intake and coronary artery disease in the cholesterol-fed rabbit
Ma, G., D. B. Young, et al. (1999), Am J Hypertens 12(8 Pt 1): 821-5.
Abstract: We tested the hypothesis that a low level of dietary potassium intake would exacerbate the severity of vascular lesion formation in rabbit coronary arteries during high cholesterol intake. Two groups of nine rabbits were studied for 6 weeks while eating a diet containing 2% cholesterol and 0.9% sodium. The normal potassium group consumed a diet containing 1.5% potassium and the low potassium group consumed a diet containing 0.4% potassium. After 6 weeks the animals were killed, the hearts were removed, and blood samples were withdrawn from the abdominal aorta immediately before removing the heart. The hearts were sectioned and slides were prepared and fixed with hematoxylin and eosin. The numbers of normal and abnormal vessels, and those with foam cells in the subintima, were counted in selected sections. Plasma potassium concentration in the normal and low potassium intake groups averaged 4.27 +/- 0.27 mmol/L and 3.90 +/- 0.11 mmol/L, respectively. No differences between the groups were observed in plasma cholesterol or body weight gain. The percentages of abnormal arteries in the groups were 4.20 +/- 0.35 in the normal intake group and 6.36 +/- 0.50 in the low intake group, 51% greater in the normal intake group (P <.001). These results support the hypothesis that low potassium intake exacerbates the severity of subintimal lesion development in the coronary arteries.

Investigation into the role of apolipoprotein B gene 8344C/T variant on plasma cholesterol levels by allele-specific PCR amplification
Cantafora, A., S. Bertolini, et al. (2002), Ann Ist Super Sanita 38(4): 411-8.
Abstract: The 8344C/T polymorphism of the apoB gene was genotyped by an original modification of PCR allele-specific amplification consisting in a single amplification reaction double-primed by two opposite allele-specific oligonucleotides nested in a larger amplified fragment. This method was used to genotype 200 randomly selected healthy individuals (113 males, 87 females). The frequency of the rare allele in this random Italian population was 0.240, i.e. not far from the 0.282 frequency observed in hypocholesterolemic Norwegians and suggestive of a moderating effect on LDL levels of our population. However, we did not find any significant cholesterol-lowering effect of this polymorphism either by comparing the frequency of mutant alleles in the population stratified for its plasma lipoprotein levels or by studying the association between ApoB genotype and the different lipoproteins. In conclusion this ApoB polymorphism appeared to have a secondary role in LDL- and HDL-cholesterol variations of our population.

Investigation of cholesterol, bilirubin, and protein distribution in human gallstones by color cathodoluminescence scanning electron microscopy and transmission electron microscopy
Loginov, A. S., S. M. Chebanov, et al. (1998), Scanning 20(1): 17-22.
Abstract: The application of color cathodoluminescent scanning electron microscopy (CCL-SEM) for qualitative luminescence analysis of cholesterol, bilirubin, and protein in human gallastones was demonstrated. Images of these deposits (cholesterol, bilirubin, and protein) were formed in real colors (blue-cholesterol, red, orange-bilirubin, yellow, green-protein) in accordance with the cathodoluminescent spectrum for each control material. The other method described for transmission electron microscopy (TEM) of ultrathin sections provides more detailed characterization of the ultrastructure of cholesterol-containing regions and their spatial interrelations with bilirubin-containing regions. Using CCL-SEM combined with TEM permits the receipt of more complete information about the chemical composition and ultrastructure of gallstones and may lead to more effective understanding of the pathogenesis of cholesterol cholelithiasis.

Investigation of completed suicide and genes involved in cholesterol metabolism
Lalovic, A., A. Sequeira, et al. (2004), J Affect Disord 79(1-3): 25-32.
Abstract: Background: Several lines of evidence support the association between low or lowered levels of serum total cholesterol and suicide. Genetic epidemiological studies suggest that genes predispose to suicide. Given that genes control many aspects of cholesterol biosynthesis and metabolism, one approach through which to explore the putative association between low cholesterol and suicide is through genetic studies. Methods: We examined the potential role of five genes encoding proteins involved in cholesterol biosynthesis and transport in a total sample of 305 male Caucasian subjects, consisting of 145 suicide completers and 160 controls. We investigated variation in the HMG CoA reductase (HMGCR), 7-dehydrocholesterol reductase (DHCR7), lipoprotein lipase (LPL), low-density lipoprotein receptor (LDLR), and apolipoprotein E (APOE) genes. Results: We were unable to detect significant differences in allele or genotype frequencies between the suicide cases and controls for any of the genes studied. No relationship was found between genotype and impulsivity or aggression as measured using the BIS and BDHI, respectively. Limitations: The limitations of this study are consistent with the typical limitations inherent in most genetic association studies involving complex behavioral traits. Conclusion: Although these genes are unlikely to play a major role in susceptibility to suicide, further studies in a larger sample are necessary to reveal the smaller genetic effects, if present.

Investigation of endogenous nitric oxide vascular function in the carotid artery of cholesterol-fed rabbits
Laight, D. W., J. Matz, et al. (1996), Br J Pharmacol 117(7): 1471-4.
Abstract: 1. The function of endogenous nitric oxide (NO) at the level of vascular smooth muscle, was assessed in a popular experimental model of accelerated atherosclerosis, the cholesterol-fed rabbit. 2. Endothelium-dependent vasorelaxation in response to acetylcholine (ACh, 1 microM) was significantly impaired in the carotid artery from rabbits maintained on a 1% (W/W) cholesterol diet for 8-10 weeks. Furthermore, the ability of an inhibitor of nitric oxide synthase (NOS), NG-nitro-L-arginine methyl ester (L-NAME, 1-300 microM), to enhance the contractile reactivity to a submaximal concentration of noradrenaline (NA, 3 microM), was significantly attenuated in hypercholesterolaemia. 3. A significant linear correlation between the maximal contractile effect of L-NAME (300 microM) and maximal vasorelaxation to ACh (1 microM) was determined in the carotid artery from control rabbits. In contrast, no such linear correlation was found in the carotid artery from hypercholesterolaemic rabbits. 4. We conclude that there are lesions both in agonist-stimulated, endogenous NO-dependent vasorelaxation and in the regulation of vasoconstrictor reactivity by endogenous NO in the hypercholesterolaemic rabbit carotid artery. Furthermore, the normal linear relationship between the contractile effect of L-NAME and vasorelaxation to ACh is lost after cholesterol-feeding.

Investigation of gene expressions related to cholesterol metabolism in rats fed diets enriched in n-6 or n-3 fatty acid with a cholesterol after long-term feeding using quantitative-competitive RT-PCR analysis
Fukushima, M., K. Shimada, et al. (2001), J Nutr Sci Vitaminol (Tokyo) 47(3): 228-35.
Abstract: We have developed a method to quantitate hepatic apolipoprotein (apo) B, LDL receptor, 3-hydroxy-3-methylglutary coenzyme A reductase (HMG-CoA reductase) and cholesterol 7alpha-hydroxylase mRNA expression in rats fed a cholesterol-enriched diet after long-term feeding using competitive RT-RCR. Rats (8 wk of age) fed a conventional diet were shifted to diets containing 10% perilla oil (PEO, oleic acid+linoleic acid+alpha-linolenic acid), borage oil (BRO, oleic acid+linoleic acid+gamma-linolenic acid), evening primrose oil (EPO, linoleic acid+gamma-linolenic acid), mixed oil (MIO, oleic acid+linoleic acid+gamma-linolenic acid+alpha-linolenic acid), or palm oil (PLO, palmitic acid+oleic acid+linoleic acid) with 0.5% cholesterol for 15 wk. There were no significant differences in the food intake and body weight gain among the groups. The liver weight in the PEO and PLO groups was significantly higher than other groups. The serum total cholesterol and very low density lipoprotein (VLDL)+intermediate density lipoprotein (IDL)+low density lipoprotein (LDL)-cholesterol concentrations were consistently higher in PLO group than in the other groups. The serum high density lipoprotein cholesterol concentration was significantly lower in the PEO group than in the other groups. The liver cholesterol concentration group was significantly higher in the PEO than in the other groups. There were no significant differences in the hepatic LDL receptor mRNA level among the groups. Hepatic apo B, HMG-CoA reductase and cholesterol 7alpha-hydroxylase mRNA levels were not affected by the experimental conditions. However, hepatic cholesterol 7alpha-hydroxylase mRNA level in the PEO and MIO groups tended to be higher than in the other groups. The fecal cholesterol extraction was significantly higher in the MIO and PLO groups than in the PEO and EPO groups and the total bile acid extraction was significantly higher in the PEO and MIO groups than in the PLO group. The results of this study demonstrated that both n-6 fatty acid and n-3 fatty acids such as gamma-linolenic acid and alpha-linolenic acid lowered serum total cholesterol and VLDL+IDL+LDL-cholesterol concentrations of rats in the presence of excess cholesterol in the diet compared with dietary saturated fatty acid.

Investigation of lipid transfer in human serum leading to the development of an isotopic method for the determination of endogenous cholesterol esterification and transfer
Channon, K. M., R. J. Clegg, et al. (1990), Atherosclerosis 80(3): 217-26.
Abstract: The rate at which radioactivity appeared in cholesteryl esters (CE) in whole serum and in very low density lipoproteins (VLDL) and low density lipoproteins (LDL) when radioactively labelled free cholesterol (FC) was incubated with serum was investigated. At 4 degrees C equilibration of radioactive FC with native FC occurred, but there was no conversion to CE. At 37 degrees C CE mass increased in parallel with radioactivity in CE both in whole serum and VLDL/LDL. Incubation at 37 degrees C with an inhibitor of lecithin cholesterol acyl transferase (LCAT) abolished the increase in the total CE radioactivity and mass in serum. Transfer of CE from high density lipoprotein (HDL) to VLDL/LDL, however, continued to occur. An assay for LCAT and for cholesteryl ester transfer protein (CETP) was developed, which employed the increases in radioactive CE in whole serum and VLDL/LDL during a single incubation as indices of LCAT and CETP activity, respectively. Determination of the initial serum FC concentration allowed the expression of these activities in nmol/ml per h. References ranges were established in 62 fasting normolipidaemic men and women and increases in both LCAT and CETP were found following a fatty meal. The experiments thus provided further information about the carrier-mediated transfer of CE from its site of esterification on HDL to VLDL/LDL and formed the basis of a relatively simple assay, which has advantages over previously published methods and which may be used in clinical and epidemiological studies to elucidate the role of CETP and LCAT in atherosclerosis.

Investigation of the effect of coffee lipids on serum cholesterol in hamsters
Ratnayake, W. M., G. Pelletier, et al. (1995), Food Chem Toxicol 33(3): 195-201.
Abstract: The effect of coffee total lipids (CTL), coffee non-saponifiable matter (NSM) and coffee diterpene alcohols (DTA) extracted from Coffea arabica beans on serum cholesterol in adult male Syrian hamsters was examined. The animals were fed either a commercial laboratory chow diet (study 1), containing 5% fat and low in saturated fat (1.46 g/100 g diet) and cholesterol (0.03 g/100 g diet) or a semi-synthetic diet (study 2) set in gelatine, containing 10% fat and high in saturated fat (4 g/100 g diet) and cholesterol (0.5 g/100 g diet). The coffee lipid extracts were dissolved in olive oil (concentration either 5 mg CTL, 0.5 mg NSM or 0.5 mg DTA per 250 microliters olive oil) in study 1 and in coconut oil (concentration either 20 mg CTL, 2 mg NSM or 2 mg DTA per 250 microliters) in study 2. A dose of 250 microliters of these solutions was administered daily to hamsters by gavage. Control animals received 250 microliters vehicle only. For serum lipid analysis, blood samples were obtained on days 0, 7 and 14 in study 1 and on days 0, 7, 14 and 21 in study 2. Statistical analyses of the data in Study 1 indicated a tendency for serum total cholesterol and high density lipoprotein-cholesterol to increase with administration of CTL, NSM and DTA. In contrast, in study 2 there were no significant differences in serum lipid levels between control and coffee lipid-treated groups across time. In either study, total serum cholesterol levels of the three coffee lipid groups were not significantly different from each other. These results support the concept that coffee lipids may be hypercholesterolaemic and indicate that diterpenes could be the lipid component responsible for such an effect. However, it appears that this hypercholesterolaemic effect is apparent only when the background diet is low in saturated fat and cholesterol. A high saturated fat/high cholesterol diet may mask the hypercholesterolaemic effect of coffee lipids.

Investigation of the effects of a sapogenin-rich preparation from a Jamaican yam (Dioscorea sp.) on blood cholesterol levels in rats
McKoy, M. L., F. Omoruyi, et al. (2003), Proc West Pharmacol Soc 46: 156-9.

Investigation of the low-density lipoprotein receptor gene and cholesterol as a risk factor for migraine
Curtain, R., R. A. Lea, et al. (2004), J Neurol Sci 227(1): 95-100.
Abstract: The Low-Density Lipoprotein Receptor (LDLR) gene is a cell surface receptor that plays an important role in cholesterol homeostasis. We investigated the (TA)n polymorphism in exon 18 of the LDLR gene on chromosome 19p13.2 performing an association analysis in 244 typical migraine-affected patients, 151 suffering from migraine with aura (MA), 96 with migraine without aura (MO) and 244 unaffected controls. The populations consisted of Caucasians only, and controls were age- and sex-matched. The results showed no significant difference between groups for allele frequency distributions of the (TA)n polymorphism even after separation of the migraine-affected individuals into subgroups of MA and MO affected patients. This is in contradiction to Mochi et al. who found a positive association of this variant with MO. Our study discusses possible differences between the two studies and extends this research by investigating circulating cholesterol levels in a migraine-affected population.

Investigation of the potential genotoxicity of cholesterol oxidation products in two mammalian fibroblast cell lines
Woods, J. A. and N. M. O'Brien (1998), Nutr Cancer 31(3): 192-8.
Abstract: Cholesterol oxidation products (oxysterols) are generated during the cooking and processing of foods and may be produced endogenously in tissues and in the plasma membrane. A diverse range of biological functions have been ascribed to oxysterols, including atherogenicity, carcinogenicity, and mutagenicity, and in recent years concern has been expressed over the presence of oxysterols in food products. However, it is unclear whether oxysterols are capable of inducing genotoxic damage in cell culture systems. The aim of this study was to examine seven commonly occurring oxysterols (purity > 95%) for their cytotoxicity and ability to increase the frequency of DNA strand breaks and sister chromatid exchanges (SCE) in cells in culture. Two cell lines were employed in the study: Chinese hamster ovary (CHO) and Indian Muntjac (IM) fibroblasts. The 3-(4,5-dimethylthiozol-2-yl)-2,5-diphenyltetrazolium bromide assay, which is a measure of intracellular reductive metabolism based on the activity of mitochondrial dehydrogenases, was used as an index of cytotoxicity. The most cytotoxic oxysterols in constantly challenged CHO or IM cells (24-h exposure) proved to be 5 alpha-cholestane-3 beta,5,6 beta-triol and 25-hydroxy-cholesterol. The genotoxic potential of the oxysterols was assessed in CHO cells using the comet assay and IM cells using the SCE assay. The comet assay measures breaks in the DNA strand, whereas the exact mechanism of SCE formation is unclear but is believed to require DNA repair where genetic material becomes exchanged between the two sister chromatids. None of the oxysterols examined in this study affected baseline levels of DNA strand breaks or SCE relative to the negative control samples. This study indicates that, under the conditions used, the oxysterols investigated were not genotoxic.

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