Anti-atherogenic properties of Kgengwe (Citrullus lanatus) seed powder in low-density lipoprotein receptor knockout mice are mediated through beneficial alterations in inflammatory pathways.

Kgengwe fruits are commonly consumed in sub-Saharan countries. Recent reports indicated low coronary artery disease rates in those regions. To investigate anti-atherogenic properties and potential mechanisms of action of Kgengwe seed powder (KSP), male low-density lipoprotein receptor knockout (LDL-r-KO) mice were fed with an atherogenic diet supplemented with (treated, n = 10) or without (controls, n = 10) 10% (w/w) KSP for 20 weeks. Proximate analysis revealed that KSP contained 38% fibre and 15% lipids. KSP supplementation was not associated with significant changes in body weight gain rate, food intake, and plasma lipid levels. However, the average atherosclerotic lesion size in the aortic roots in the KSP-treated group was 58% smaller than that in the control group (0.26 vs 0.11 mm2, p < 0.05). This strong anti-atherogenic effect was associated with significant increases in the average plasma levels of certain cytokines such as IL-10 (6 vs 13 pg/mL, p < 0.05), GM-CSF (0.1 vs 0.2 pg/mL, p < 0.05), and EPO (7 vs 16 pg/mL, p < 0.05) along with reductions in the average levels of plasma MCP-1 (19 vs 14 pg/mL, p < 0.05) and MIP-2 (28 vs 13 pg/mL, p < 0.05). Except for relatively high levels of saturated fatty acids, KSP possesses balanced nutrient compositions with strong anti-atherogenic properties, which may be mediated through alterations in inflammatory pathways. Additional studies warrant confirmation and mechanism(s) of action of such effects. Novelty: Kgengwe seeds prevent atherogenesis in LDL-r-KO mice. Kgengwe seeds increase circulating levels of IL-10 and EPO. No reduction in plasma total cholesterol levels.

Dietary fatty acids affect semen quality: a review.

Mammalian spermatozoa are characterized by a high proportion of polyunsaturated fatty acids (PUFA) which play a crucial role in fertilization. This review focuses on analysis of sperm fatty acid profiles and the effects of omega-3, saturated and trans dietary and sperm fatty acids on sperm parameters. Two major points have been pivotal points of investigation in the field of sperm fatty acid profiles: first, the comparison between fatty acid profiles of fertile and infertile men and second, the effect of dietary fatty acids on sperm fatty acid profiles as well as sperm quality and quantity. Docosahexaenoic acid (DHA, C22:6n-3), and palmitic acid (C16:0) are the predominant PUFA and saturated fatty acids, respectively, in human sperm cells. Higher levels of DHA are concentrated on the sperm's head or tail varying among different species. However, the human sperm head contains a higher concentration of DHA. Dietary fatty acids influence on sperm fatty acid profiles and it seems that sperm fatty acid profiles are most sensitive to dietary omega-3 PUFA. Although improvements in sperm parameters are a response to omega-3 sources after more than 4 weeks of supplementation in the male diet, time-dependent and dose-dependent responses may explain the failure in some experiments. In human spermatozoa, elevated saturated or trans fatty acid concentration and a low DHA level is a concern. The regulations of the sperm fatty acid mean melting point as well as expression regulation of peroxisome proliferator-activated receptor gamma (PPARG) alongside with spermatozoon assembly, anti-apoptosis effects, eicosanoid formation, and hormone activity are the putative key factors that induce a response by inclusion of omega-3 PUFA.

Successful treatment of a morbidly obese and growth-retarded adolescent with Williams-Beuren Syndrome by combining the medication of growth hormone and sibutramine.

A 16-year-old male adolescent diagnosed to have the Williams-Beuren syndrome was referred to our obesity outpatient clinic, due to his morbid obesity (body mass index 39.2 kilograms per square metre) and gluttony. After several unsuccessful dietary treatments, we started therapy with sibutramine. As growth hormone (GH) deficiency was diagnosed by an additional GH-stimulation test, we commenced with a GH-treatment. This well-tolerated combination therapy led to a remarkable weight loss of 10 kg and a growth-rate acceleration of 3.7 cm/year. Nine months after stopping the treatment with sibutramine, a partial weight gain was noticed. This case report justifies further research work on a combination therapy with sibutramine and GH for similar cases.

Factors affecting food selection in Canadian population.

OBJECTIVE: To establish health-related reasons behind Canadian food choices, and how variables such as education, income, gender, ethnicity and age may affect food selection. SUBJECTS: Approximately 98 733 Canadians responded to the 12 questions regarding food choices in the Canadian Community Health Survey (CCHS) cycle 2.1, conducted by the Canadian Government in 2003. These included 13 727 adolescents (12-19 years), 19 089 young adults (20-34 years), 31 039 middle-aged adults (35-54 years), 25 338 older adults (55-74 years) and 9580 elderly (75+ years). RESULTS: Approximately 70% of Canadian adolescents in the sample indicated that their food choices were independent of health concerns. Body weight management was a major concern for food selection by adolescents and adults, while the elderly stated heart disease as their main concern. Among all participants, females, and individuals with high levels of education and income reported the highest response to choosing or avoiding foods due to health concerns and food content. CONCLUSIONS: Our data indicate that several factors significantly affect food choices for health-related reasons in the Canadian population. Among them, age- and gender-related gaps, particularly between adolescents and adults, are profound. This observation may urge authorities to implement effective strategies to educate Canadians, especially adolescents, that selection of appropriate foods may prevent chronic diseases.

Examining the interaction of apo E and neurotoxicity on a murine model of ALS-PDC.

Epidemiological studies have shown a positive relationship between cycad flour consumption and the development of the neurodegenerative disorder, amyotrophic lateral sclerosis - parkinsonism - dementia complex (ALS-PDC). Apolipoprotein E (apo E) allele variations have been associated with genetic susceptibility in neurodegenerative diseases, including ALS-PDC. We have studied cycad toxicity in a mouse model of ALS-PDC with a particular interest in its impact on the central nervous system (CNS) in both apo E knock-out (KO) mice and their wild-type (WT) counterparts. Behavioral motor tests, motor neuron counts, and immunohistochemical staining in brain and spinal cord, as well as routine histological examinations on internal organs, were performed to evaluate cycad toxicity. Plasma cholesterol levels were also measured before and during the study. Cycad treatment was associated with higher levels of plasma cholesterol only in apo E KO mice; increased levels of plasma cholesterol did not result in increased athero genesis. Cycad-fed wild-type mice developed progressive behavioral deficits including ALS-PDC-like pathological outcomes, while cycad-fed apo E KO mice were not significantly affected. Cycad-fed wild-type mice had shorter gait length measurements along with higher active caspase-3 levels in the striatum, substantia nigra, primary motor cortex, and spinal cord as compared with corresponding controls. These changes were associated with decreased labeling for glutamate transporter 1B and tyrosine hydroxylase activity levels. No evidence of cycad toxicity was observed in internal organs of either wild-type or apo E KO mice. Our data demonstrate that apo E KO mice are less susceptible to cycad toxicity, suggesting a role for apo E as a possible genetic susceptibility factor for some forms of toxin-induced neurodegeneration.

Specificity of the commonly used enzymatic assay for plasma cholesterol determination.

AIM: To assess the specificity and sensitivity of the commonly used enzymatic colorimetric test for plasma cholesterol determination. METHODS: Interference with an enzymatic method for cholesterol measurement by several non-cholesterol sterols (beta sitosterol, campesterol, stigmasterol, stigmastanol, desmosterol, and lathosterol) was assessed. Some of these compounds are present in plasma at higher than normal concentrations either in rare genetic disorders, such as phytosterolaemia, or after the consumption of phytosterol enriched foods. RESULTS: The non-cholesterol sterols were detected by the assay in a linear manner. There was no competitive interference in the presence of cholesterol. CONCLUSIONS: This crossreactivity may affect the diagnosis and treatment of non-cholesterol dyslipidaemias, including phytosterolaemia and cerebrotendinous xanthomatosis. Similarly, changes in plasma lipid compositions after the consumption of phytosterol enriched foods cannot be specifically determined by this enzymatic assay. Until a more specific enzymatic assay is developed, alternative methods such as gas chromatography should be used to differentiate between cholesterol and non-cholesterol sterols.

Pathophysiology of apolipoprotein E deficiency in mice: relevance to apo E-related disorders in humans.

Apolipoprotein E (apo E) deficiency (or its abnormalities in humans) is associated with a series of pathological conditions including dyslipidemia, atherosclerosis, Alzheimer's disease, and shorter life span. The purpose of this study was to characterize these conditions in apo E-deficient C57BL/6J mice and relate them to human disorders. Deletion of apo E gene in mice is associated with changes in lipoprotein metabolism [plasma total cholesterol (TC) (>+400%), HDL cholesterol (-80%), HDL/TC, and HDL/LDL ratios (-93% and -96%, respectively), esterification rate in apo B-depleted plasma (+100%), plasma triglyceride (+200%), hepatic HMG-CoA reductase activity (-50%), hepatic cholesterol content (+30%)], decreased plasma homocyst(e)ine and glucose levels, and severe atherosclerosis and cutaneous xanthomatosis. Hepatic and lipoprotein lipase activities, hepatic LDL receptor function, and organ antioxidant capacity remain unchanged. Several histological/immunohistological stainings failed to detect potential markers for neurodegenerative disease in the brain of 37-wk-old male apo E-KO mice. Apo E-KO mice may have normal growth and development, but advanced atherosclerosis and xanthomatosis may indirectly reduce their life span. Apo E plays a crucial role in regulation of lipid metabolism and atherogenesis without affecting lipase activities, endogenous antioxidant capacity, or appearance of neurodegenerative markers in 37-wk-old male mice.

Advances in experimental dyslipidemia and atherosclerosis.

Among the models of dyslipidemia and atherosclerosis, a number of wild-type, naturally defective, and genetically modified animals (rabbits, mice, pigeons, dogs, pigs, and monkeys) have been characterized. In particular, their similarities to and differences from humans in respect to relevant biochemical, physiologic, and pathologic conditions have been evaluated. Features of atherosclerotic lesions and their specific relationship to plasma lipoprotein particles have been critically reviewed and summarized. All animal models studied have limitations: the most significant advantages and disadvantages of using a specific animal species are outlined here. New insights in lipid metabolism and genetic background with regard to variations in pathogenesis of dyslipidemia-associated atherogenesis have also been reviewed. Evidence suggests that among wild-type species, strains of White Carneau pigeons and Watanabe Heritable Hyperlipidemic and St. Thomas's Hospital rabbits are preferable to the cholesterol-fed wild-type animal species in dyslipidemia and atherosclerosis research. Evidence for the usefulness of both wild-type and transgenic animals in studying the involvement of inflammatory pathways and Chlamydia pneumoniae infection in pathogenesis of atherosclerosis has also been summarized. Transgenic mice and rabbits are excellent tools for studying specific gene-related disorders. However, despite these significant achievements in animal experimentation, there are no suitable animal models for several rare types of fatal dyslipidemia-associated disorders such as phytosterolemia and cerebrotendinous xanthomatosis. An excellent model of diabetic atherosclerosis is unavailable. The question of reversibility of atherosclerosis still remains unanswered. Further work is needed to overcome these deficiencies.

Overexpression of acyl-coA binding protein and its effects on the flux of free fatty acids in McA-RH 7777 cells.

Overexpression of acyl-CoA binding protein (ACBP) was induced in a rat hepatoma cell line (McA-RH 7777) by stable integration of rat ACBP cDNA. The transfected cells (ACBP-27) had 3.5-fold higher concentrations of ACBP than control cells (14 vs. 4 ng/microg DNA). Both ACBP-27 and control cells were cultured in the presence of various concentrations of radiolabeled palmitic acid; and the effects of ACBP on lipogenesis and beta-oxidation were studied. Incubation of the cells with 100 microM palmitic acid resulted in 42% greater incorporation of the fatty acid in ACBP-27 cells as compared to that in the control cells. This increased incorporation of the fatty acid was observed predominantly in the triglyceride fraction. Higher concentrations of palmitic acid (200 to 400 microM) were associated with a significant decrease in the production of 14CO2 in the ACBP-27 cell line than in the control cells, while lower concentrations had no effect. Our data suggest a role for ACBP in the partitioning of fatty acids between esterification reactions leading to the formation of neutral lipids and beta-oxidation. ACBP may play a regulatory role by influencing this important branch point in intermediary lipid metabolism.

Surgical management of dyslipidemia: clinical and experimental evidence.

Coronary artery disease (CAD) is still a major cause of mortality in developed countries, and dyslipidemia is one of its major causes. In an attempt to reduce both mortality and morbidity from CAD, several dietary, pharmacological, and surgical approaches have been used to reduce plasma cholesterol levels. In this brief review, we summarize the evidence for cholesterol-lowering effects and safety of partial ileal bypass (PIB) procedure in both human and animal studies. The results of the Program on the Surgical Control of the Hyperlipidemias (POSCH), which involved a total of 838 subjects with myocardial infarction, are promising. A 5-year follow-up of this study revealed significant reductions of up to 27% in total cholesterol (TC) and up to 42% in low-density lipoprotein (LDL) cholesterol levels along with an increase of up to 8% in high-density lipoprotein (HDL) cholesterol levels as compared to controls. These changes were associated with other benefits such as increased HDL/TC and HDL/LDL ratios, and a significant decrease in apolipoprotein (apo) B100 and increase in apo AI levels. Similar results were also demonstrated by other studies. PIB surgery is one of the most effective methods for reduction of plasma cholesterol levels, particularly in patients with heterozygous familial hypercholesterolemia. This procedure is also applicable to treatment of sitosterolemia, a rare genetic disorder in which the absorption of plant sterols is abnormally high. Although no major complications of this method have been reported, more extensive studies are required to evaluate its long-term effects on renal and hepatic function. Similarly, long-term impact of this procedure on progression/regression of atherosclerotic lesions must be documented. Finally, indications for this procedure should be carefully considered, particularly in view of availability of other treatments of dyslipidemia.

Hepatic cholesterol and bile acid synthesis, low-density lipoprotein receptor function, and plasma and fecal sterol levels in mice: effects of apolipoprotein E deficiency and probucol or phytosterol treatment.

We compared hepatic cholesterol metabolism in apolipoprotein (apo) E-knockout (KO) mice with their wild-type counterparts. We also investigated the effects of treatment with phytosterols or probucol on the activity of hepatic 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase (cholesterol synthesis), cholesterol 7 alpha-hydroxylase and sterol 27-hydroxylase (bile acid synthesis), and low-density lipoprotein (LDL) receptor function in this animal model of atherogenesis. These findings were then related to treatment-induced changes in plasma, hepatic, and fecal sterol concentrations. Mouse liver membranes have binding sites similar to LDL receptors; the receptor-mediated binding represents 80% of total binding and is LDL concentration-dependent. These binding sites have higher affinity for apo E-containing particles than apo B only-containing particles. Deletion of apo E gene was associated with several-fold increases in plasma cholesterol levels, 1.5-fold increase in hepatic cholesterol concentrations, 50% decrease in HMG-CoA reductase activity, 30% increase in cholesterol 7 alpha-hydroxylase and 25% decrease in LDL receptor function. Treatment of apo E-KO mice with either probucol or phytosterols significantly reduced plasma cholesterol levels. Phytosterols significantly increased the activity of hepatic HMG-CoA reductase, and probucol significantly increased cholesterol 7 alpha-hydroxylase activity. Neither treatment significantly altered hepatic LDL receptor function. Phytosterols, but not probucol, significantly increased fecal sterol excretion and decreased hepatic cholesterol concentrations. Plasma cholesterol lowering effects of phytosterols and probucol are due to different mechanisms: stimulation of cholesterol catabolism via increased bile acid synthesis by probucol and decreased cholesterol absorption by phytosterols. In the absence of apo E, hepatic LDL receptors could not be upregulated and did not contribute to the cholesterol lowering effects of either agent.

Assessing plasma pharmacokinetics of cholesterol following oral coadministration with a novel vegetable stanol mixture to fasting rats.

The purpose of this project was to assess the plasma pharmacokinetics of [(3)H]cholesterol following coadministration of a novel vegetable stanol mixture composed of sitostanol and campestanol (FCP-3P4) to fasting rats. Following an overnight fast (12-16 h) and 48 h post-surgery, adult male Sprague Dawley rats were divided into six treatment groups and received a single-dose oral gavage at 0700 h of either: [(3)H]cholesterol (25 microCi/mL), FCP-3P4 (5 mg/kg) + [(3)H]cholesterol (25 microCi/mL), FCP-3P4 (12.5 mg/kg) + [(3)H]cholesterol (25 microCi/mL), FCP-3P4 (25 mg/kg) + [(3)H]cholesterol (25 microCi/mL), FCP-3P4 (50 mg/kg) + [(3)H]cholesterol (25 microCi/mL), or FCP-3P4 (100 mg/kg) + [(3)H]cholesterol (25 microCi/mL). Intralipid (10%) was the vehicle used to solubilize and coadminister [(3)H]cholesterol and FCP-3P4. Liquid chromatography-mass spectrometry analysis confirmed minimal cholesterol and vegetable stanol content within 10% Intralipid. Analysis of plasma pharmacokinetics was initiated by sampling 0.5 mL of blood prior to and 0.25, 0.5 1.0, 2.0, 4.0, 6.0, 8.0, 10, 24, 28, 32, and 48 h post-oral gavage. Plasma samples were obtained by centrifugation of the blood samples and analyzed for [(3)H]cholesterol radioactivity. Pharmacokinetics analysis was performed by standard noncompartmental methods using statistical moment theory. Thin-layer chromatography was used to confirm that the majority of radioactivity measured in plasma was cholesterol (in the form of esterified or unesterified cholesterol). Greater than 90% of the radioactivity measured in all plasma samples was cholesterol-associated (in the form of either esterified or unesterified cholesterol). The coadministration of FCP-3P4 significantly decreased the area under the curve of [(3)H]cholesterol concentration versus time from 0 to 48 h (AUC(0-48h)) and maximum concentration (C(max)) in a dose-dependent manner. However, coadministration of FCP-3P4 at 25, 50, and 100 mg/kg resulted in a significant increase in apparent total body clearance (CL/F, where F is the bioavailability constant), apparent volume of distribution (V(d)/F), and oral absorption rate constant (k(a)) of [(3)H]cholesterol compared with controls. These findings suggest that the novel vegetable stanol mixture, FCP-3P4, modifies the plasma pharmacokinetics of [(3)H]cholesterol in fasting rats on oral coadministration.

Pharmacotherapy of hypercholesterolaemia: statins in clinical practice.

The objective of this article is to evaluate the roles of the lipid-lowering class of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) in reducing cardiovascular events and to review their mechanism of action based on in vitro and in vivo studies. The clinical outcome of 15 major clinical trials has been critically reviewed and summarised; all showed a high degree of efficacy and safety. Statins, either in active or prodrug forms, are potent inhibitors of HMG-CoA reductase, have good absorption rate and their bioavailability depends on their lipophobicity and concomitant use with meals. Abdominal discomfort is the most commonly reported adverse effect. Although the incidence is low, myopathy with or without rhabdomyolysis may be considered a serious adverse effect of statins. A combination of a statin with gemfibrozil seems to increase the risk of this adverse event, particularly in patients with renal impairment. Combination therapy with several other agents, frequently administered to cardiovascular patients, has also been reviewed. Statin therapy is considered highly cost effective in secondary prevention, but it is less cost effective in primary prevention. This factor may underline the rationale for developing other safe and effective agents with an improved cost effectiveness profile. The pleiotropic non-lipid lowering effects of statins may include their anti-oxidant and antithrombotic potential as well as restoration of endothelial function. Statins may also be beneficial in the treatment of osteoporosis. Fewer studies have investigated statins' effects on the quality of lipoprotein particles, the activities of cholesteryl ester transfer protein and lecithin:cholesterol acyltransferase as well as their possible synergistic effects with n-3 fatty acids, anti-oxidants and aspirin in reducing cardiovascular events.

Pharmacological properties of plant sterols in vivo and in vitro observations.

Plant sterols have been investigated as one of the safe potential alternative methods in lowering plasma cholesterol levels. Several human studies have shown that plant sterols/stanols significantly reduce plasma total and LDL cholesterol. In this article, pharmacological characteristics of plant sterols/stanols have been summarized and discussed. In particular, experimental data that demonstrate the effects of dietary phytosterols on lipid metabolism and development of atherosclerotic lesions have been critically reviewed. Despite their similar chemical structures, phytosterols and cholesterol differ markedly from each other in regard to their pharmacological characteristics including intestinal absorption and metabolic fate. Compared to cholesterol, plant sterols have poor intestinal absorption. The most and best studied effects of plant sterols are their inhibition of intestinal cholesterol absorption. Other biological activities of phytosterols such as effects on lecithin:cholesterol acyltransferase activity, bile acid synthesis, oxidation and uptake of lipoproteins, hepatic and lipoprotein lipase activities and coagulation system have been linked to their anti-atherogenic properties. Moreover, evidence for beneficial effects of plant sterols on disorders such as cutaneous xanthomatosis, colon cancer and prostate hyperplasia has been discussed. Finally, the potential adverse effects of plant sterols as well as pathophysiology of hereditary sitosterolemia are also reviewed. In conclusion, more pharmacokinetic data are needed to better understand metabolic fate of plant sterols/stanols and their fatty acid esters as well as their interactions with other nutraceutical/pharmaceutical agents.

Clinical pharmacology of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors.

In this article, de novo cholesterol synthesis, its inhibition by HMG-CoA reductase inhibitors (statins) and clinical pharmacology aspects of the statins have been reviewed. Statins are available in both active and pro-drug forms. Their affinity to bind and subsequently to inhibit HMG-CoA reductase activity is approximately 3 orders of magnitude higher than that of natural substrate (HMG-CoA). All members of this group of lipid-lowering agents are, to a varying degree, absorbed from the gut. However, their bioavailability depends on their lipophobicity and their concomitant use with meals. The interaction between HMG-CoA reductase inhibitors and other lipid-lowering agents has been reviewed in more detail. One major side-effect of lipid-lowering combination therapy is myopathy with or without rhabdomyolysis. Combination of statins with gemfibrozil seems to increase risk of this adverse event, particularly in patients with renal impairment, more than combination with other lipid-lowering agents. Combination therapy with other agents including anticoagulants, antihypertensive, anti-inflammatory, oral hypoglycemic and antifungal agents as well as beta-blockers, H2 blockers, cyclosporine and digoxin has been also reviewed. The pleiotropic non-lipid lowering properties of statins and their effects on the quality of lipoprotein particles, the activities of cholesteryl ester transfer protein and lecithin:cholesterol acyltransferase as well as their possible synergistic effects with n-3 fatty acids, phytosterols, vitamin E and aspirin in reducing cardiovascular events warrant further investigation.

Lack of regression of atherosclerotic lesions in phytosterol-treated apo E-deficient mice.

We evaluated the effects of a phytosterol mixture (FCP-3PI) on the regression of atherosclerotic lesions in male apo E-deficient mice. Atherosclerosis was induced in fifteen mice by a "Western-type" diet containing 9% (w/w) fat and 0.15% (w/w) cholesterol over a period of 18 weeks (Induction phase). Then, two mice were used to evaluate the development of atherosclerosis, and the rest was divided into the control (n=6) and treated (n=7) groups. The control group was fed mouse chow (4.5% w/w fat) and the treated group fed the same chow supplemented with 2% (w/w) FCP-3PI for an additional 25 weeks (Regression phase). The mice developed severe hypercholesterolemia and advanced atherosclerotic lesions over the induction phase. During the first 6 weeks of regression phase, plasma cholesterol concentrations decreased at a similar rate (35%) in both groups of control and phytosterol-treated mice. Although evidence of lesion regression was not observed in either group of mice, the treated group had slightly smaller lesion size than the controls. During the induction phase, each mouse developed atherosclerotic lesions averaging 0.025 mm2 per week. However, during the regression phase, this was decreased to approximately one fifth and one third in the treated and control groups, respectively. Thus, compared to the end of the induction phase, the control group had a 40% increase in the lesion size, while this increase was only 28% in the treated animals. In conclusion, our previous findings along with a small decrease in the atherosclerotic lesion size observed in the treated group in the present study suggest that FCP-3PI treatment may slow the development of atherosclerotic lesions in apo E-deficient mice; however, a longer regression period may yield a greater benefit.

Proatherogenic and antiatherogenic effects of probucol and phytosterols in apolipoprotein E-deficient mice: possible mechanisms of action.

BACKGROUND: The effects of probucol and a phytosterol mixture (FCP-3PI) on atherosclerotic lesion formation, plasma lipoproteins, hepatic and lipoprotein lipase activities, antioxidant enzyme activities, and plasma fibrinogen were investigated in apolipoprotein E-knockout (apoE-KO) mice. METHODS AND RESULTS: Three groups of 8 mice were fed a diet containing 9% (wt/wt) fat (controls) or the foregoing diet supplemented with either 1% (wt/wt) probucol (the probucol group) or 2% (wt/wt) FCP-3PI (the FCP-3PI group) for 20 weeks. Compared with controls, atherosclerotic lesion size was 3 times greater in the probucol group, whereas it was decreased by half in the FCP-3PI group. Probucol treatment resulted in high plasma probucol concentrations, which correlated (r=0.69) with the lesion area. HDL cholesterol was reduced (>75%) in the probucol group and slightly increased (14%) in the FCP-3PI-treated group. Postheparin lipoprotein lipase (LPL) activity was significantly reduced in both treatment groups, but only FCP-3PI significantly decreased hepatic lipase activity. Plasma fibrinogen was increased 42% by probucol and decreased 19% by FCP-3PI relative to controls. Probucol significantly increased plasma glutathione reductase, glutathione peroxidase, and superoxide dismutase activities (P<0.05). In contrast to findings in apoE-KO mice, there was no probucol-induced atherosclerosis in their wild-type counterparts fed the same dose for the same period of time. CONCLUSIONS: Antiatherogenic activity of FCP-3PI in apoE-KO mice is associated with an increase in HDL cholesterol concentration along with decreases in hepatic lipase activity and plasma fibrinogen concentrations. Proatherogenic effects of probucol may be related to increased plasma fibrinogen, decreased HDL cholesterol concentrations along with decreased LPL activity, or its direct "toxicity" due to very high plasma concentration. Our studies demonstrate that the antioxidant and cholesterol-lowering properties of probucol do not prevent atherogenesis in this particular animal model.

Histologic, hematologic, and biochemical characteristics of apo E-deficient mice: effects of dietary cholesterol and phytosterols.

In this study, we examined the effects of a "Western-type" diet containing 9% (w/w) fat and 0.15% (w/w) cholesterol, in the presence or absence of 2% (w/w) phytosterol mixture over an 18-week period in apolipoprotein E-deficient mice. Addition of phytosterols to the high cholesterol diet was associated with normalization of the depressed hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity (from 22.3+/-6.3 to 55.4+/-19.9 pmol/mg protein/minutes, p < 0.05). This finding was associated with a significant decrease in plasma and hepatic cholesterol concentrations compared with animals fed the high cholesterol diet without phytosterols (33.3+/-5.0 versus 19.2+/-6.2 pmol/mg protein, p < 0.05). The activities of cholesterol 7alpha-hydroxylase and sterol 27-hydroxylase were comparable between the two groups of mice. Urinalyses and hematologic data were comparable between the two groups except for significantly lower platelet counts in the phytosterol-treated animals (681.6+/-118.9 versus 857.1+/-185.4 x10(9)/L, p < 0.05). The phytosterol-treated animals had significantly (p < 0.05) less fragile erythrocytes when exposed to 0.08, 0.07, or 0.05 M NaCl compared with cholesterol-fed mice. The consumption of the Western-type diet was associated with the development of xanthomatous skin lesions in 33% of the cholesterol-fed animals, but in none of the phytosterol-treated animals. Histologic examination revealed oil red O-negative vacuolation in liver and kidney parenchymal cells of the cholesterol-fed group, but not in the phytosterol-treated mice. Arrested spermatogenesis and atrophy of seminiferous tubules were observed, to a variable extent, in both groups of animals. We conclude that addition of the phytosterol mixture (2% w/w) to a Western-type diet in apolipoprotein E-deficient mice significantly decreases plasma and hepatic cholesterol concentrations, increases hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity, and prevents cutaneous xanthomatosis and vacuolation in the parenchymal cells of kidneys and livers.

Effects of dietary phytosterols on cholesterol metabolism and atherosclerosis: clinical and experimental evidence.

Although plant sterols (phytosterols) and cholesterol have similar chemical structures, they differ markedly in their synthesis, intestinal absorption, and metabolic fate. Phytosterols inhibit intestinal cholesterol absorption, thereby lowering plasma total and low-density lipoprotein (LDL) cholesterol levels. In 16 recently published human studies that used phytosterols to reduce plasma cholesterol levels in a total of 590 subjects, phytosterol therapy was accompanied by an average 10% reduction in total cholesterol and 13% reduction in LDL cholesterol levels. Phytosterols may also affect other aspects of cholesterol metabolism that contribute to their antiatherogenic properties, and may interfere with steroid hormone synthesis. The clinical and biochemical features of hereditary sitosterolemia, as well as its treatment, are reviewed, and the effects of cholestyramine treatment in 12 sitosterolemic subjects are summarized. Finally, new ideas for future research into the role of phytosterols in health and disease are discussed.