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BACKGROUND: Intake of an edible blue-green alga Nostoc commune var. sphaeroides Kützing (N. Commune) has been shown to lower plasma total cholesterol concentration, but the mechanisms behind the hypocholesterolemic effect have not been elucidated. AIM OF THE STUDY: To elucidate the mechanisms underlying the cholesterol-lowering effect of N. commune in mice. METHODS: Male C57BL/6J mice were fed the AIN-93 M diet supplemented with 0 or 5% (wt/wt) dried N. Commune for 4 weeks. Lipid levels in the plasma and liver, intestinal cholesterol absorption and fecal sterol excretion were measured. Expression of hepatic and intestinal genes involved in cholesterol metabolism was evaluated by quantitative realtime PCR. RESULTS: N. commune supplementation significantly reduced total plasma cholesterol and triglyceride concentrations by approximately 20% compared to controls. Intestinal cholesterol absorption was significantly decreased, while fecal neutral sterol output was significantly increased in N. commune-fed mice. mRNA levels of the cholesterol transporters such as Niemann Pick C1 Like 1, scavenger receptor class B type 1, ATP-binding cassette transporters G5 and A1 in small intestine were not significantly different between two groups. Hepatic lipid contents including total cholesterol, triglyceride and free cholesterol in N. commune-fed mice were not significantly altered. However, the expression of cholesterol modulating genes including sterol regulatory element binding protein-2 and 3-hydroxy-3-methylglutaryl coenzyme A reductase were significantly increased in mice fed N. commune. CONCLUSIONS: N. commune supplementation exerted a hypocholesterolemic effect in mice, largely in part, by reducing intestinal cholesterol absorption and promoting fecal neutral sterol excretion. [ABSTRACT FROM AUTHOR]

This study examined the effectiveness of consuming omega-3 fatty acid-enriched eggs (Omega Eggs) in increasing total dietary omega-3 fatty acids. Also examined was the impact of Omega Egg consumption on serum lipids. Sixteen hypercholesterolemic men and women with baseline serum total cholesterol concentrations of 5.17-7.76 mmol/L (200-300 mg/dL) followed the National Cholesterol Education Program Step I diet guidelines under the following conditions: (a) Step I diet without eggs, (b) Step I diet plus 12 regular eggs per week, and (c) Step I diet plus 12 Omega Eggs per week. The study design was a repeated 3 X 3 Latin square so that each subject received each of the three diet treatments. Consumption of Omega Eggs significantly increased omega-3 fatty acid intake (1.18 g/day) compared to consumption of regular eggs (0.71 g/day) or no eggs (0.81 g/day). The Omega Egg treatment did not significantly alter serum cholesterol or triacylglycerol concentration when all 16 subjects were included in the analysis. However, three subjects showed a significant increase in serum total cholesterol concentration when consuming regular eggs relative to no eggs. When these 'responders' consumed Omega Eggs, serum total cholesterol concentration did not increase, despite a 3-fold increase in cholesterol intake relative to no egg treatment. These data suggest that Omega Eggs (12/week) can be included in the National Cholesterol Education Program Step I diet without increased serum total cholesterol or triacylglycerol concentration. In this way, the nutritional benefits of eggs could be realized without the detrimental effects of increased cholesterol intake. /Article [ABSTRACT FROM AUTHOR]

Background: Dietary interventions for high cholesterol, a primary risk factor for cardiovascular disease, are generally considered before prescribing drugs., Objective: This study investigated the effects of whole Great Northern beans (wGNBs) and their hull (hGNB) incorporated into a high-saturated-fat (HSF) diet on cholesterol markers and hepatic/small intestinal genes involved in cholesterol regulation., Methods: Each of the 4 groups of 11 male golden Syrian hamsters at 9 wk old were fed a normal-fat [NF; 5% (wt:wt) of soybean oil], HSF [5% (wt:wt) of soybean oil + 10% (wt:wt) of coconut oil], HSF+5% (wt:wt) wGNB, or HSF+0.5% (wt:wt) hGNB diet for 4 wk. Cholesterol markers and expression of genes involved in cholesterol metabolism and absorption were analyzed from plasma, liver, intestinal, and fecal samples. Data were analyzed by 1-factor ANOVA and Pearson correlations., Results: Compared with the HSF group, the HSF+wGNB group had 62% and 85% lower plasma and liver cholesterol and 3.6-fold and 1.4-fold greater fecal excretion of neutral sterol and bile acid, respectively (P ≤ 0.05). The HSF+hGNB group had 54% lower plasma triglycerides (P < 0.001) and 53% lower liver esterified cholesterol (P = 0.0002) than the HSF group. Compared with the HSF group, the expression of small intestinal Niemann-Pick C1 like 1 (Npc1l1), acyl-coenzyme A:cholesterol acyltransferase 2 (Acat2), and ATP binding cassette transporter subfamily G member 5 (Abcg5) were 75%, 70%, and 49% lower, respectively, and expression of hepatic 3-hydroxy-3-methylglutaryl CoA reductase (Hmgr) was 11.5-fold greater in the HSF+wGNB group (P ≤ 0.05)., Conclusions: Consumption of wGNBs resulted in lower cholesterol concentration in male hamsters fed an HSF diet by promoting fecal cholesterol excretion, most likely caused by Npc1l1 and Acat2 suppression. The hGNB may partially contribute to the cholesterol-lowering effect of the wGNBs., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society for Nutrition.)

There are adverse effects associated with long-term opioid therapy (LTOT) for chronic pain and clinicians infrequently adhere to opioid treatment guideline recommendations for reducing risk and mitigating opioid-related harms. The primary goal of the Improving the Safety of Opioid Therapy (ISOT) intervention is to reduce harms related to prescription opioids. Secondary aims focus on enhancing the clinician-patient relationship and not having a negative impact on pain-related outcomes (to be examined through a non-inferiority analysis). The study is a cluster-randomized trial and the 44 primary care providers (PCPs) who enrolled were randomized to receive either (1) a two-hour educational workshop about a patient-centered approach to opioid therapy or (2) the educational workshop plus a collaborative care intervention delivered by a nurse care manager (NCM). Patients were assigned to the same condition as their treating PCP. ISOT was based on the chronic care model and includes patient and provider activation, outcomes monitoring, and feedback to the PCP over 12 months. The NCM conducted a baseline assessment with intervention patients, tracked opioid-related behaviors and outcomes, and provided decision support to the opioid-prescribing clinician about opioid safety. Between June 2016 and October 2018, 293 veterans who were prescribed LTOT for chronic pain were enrolled, completed a baseline assessment, and assigned to a treatment condition. Participants were enrolled for 12 months. Masked assessments were conducted with participants at baseline, 6-months, and 12-months. This manuscript describes study rationale, research methods, and baseline findings., (Published by Elsevier Inc.)

Background: Pinto beans contain multiple active agents such as polyphenols, flavonoids, and saponins, and have been shown to lower cholesterol, but the mechanisms involved in this effect have not been explored., Objective: This study was to investigate the changes in cholesterol metabolism in response to whole pinto beans (wPB) and their hulls (hPB) supplemented into a diet rich in saturated fat and the molecular mechanisms potentially responsible for these effects in hamsters., Methods: Forty-four 9-wk-old male Golden Syrian hamsters were randomly assigned to 4 diet groups (n = 11), including a 5% (wt:wt) fat diet [normal-fat diet (NF)], a 15% (wt:wt) fat diet [diet rich in saturated fat (HSF), saturated fatty acids accounted for 70% of total fatty acids], or HSF supplemented with 5% (wt:wt) wPB or 0.5% (wt:wt) hPB for 4 wk. Plasma, liver, intestinal, and fecal samples were collected to evaluate multiple cholesterol markers and gene targets., Results: The plasma non-high-density lipoprotein (non-HDL) concentration was significantly reduced in the wPB- and hPB-supplemented groups by 31.9 ± 3.5% and 53.6 ± 3.2%, respectively, compared with the HSF group (P < 0.01), to concentrations comparable with the NF group. The wPB-supplemented hamsters had significantly lower liver cholesterol (45.1%, P < 0.001) and higher fecal cholesterol concentrations (94.8%, P = 0.001) than those fed the HSF. The expressions of hepatic 3-hydroxy-3-methylglutaryl CoA reductase (Hmgcr) and small intestinal acyl-coenzyme A: cholesterol acyltransferase 2 (Acat2) were significantly decreased in animals administered wPB (by 89.1% and 63.8%, respectively) and hPB (by 72.9% and 47.7%, respectively) compared with their HSF-fed counterparts (P < 0.05). The wPB normalized the expression of Acat2 to the level of the NF group., Conclusion: Pinto beans remediated high cholesterol induced by HSF in male hamsters by decreasing hepatic cholesterol synthesis and intestinal cholesterol absorption, effects which were partially exerted by the hulls., (Copyright © American Society for Nutrition 2019.)

The objective of this study was to evaluate the effects of feeding wet distillers grains plus solubles (WDGS) on quality attributes of three beef muscles (longissimus lumborum, psoas major, and infraspinatus). Ninety-six, yearlings crossbred steers were randomly assigned to one of three dietary treatments (Corn, 15%, or 30% WDGS - DM basis) and fed for 133 d. No significant differences were observed in marbling score (P=0.89), marbling texture (P=0.70), and marbling distribution (P=0.36). Greater concentrations of PUFA and lower levels of 18:1(n-7) were observed in beef from steers fed 30% WDGS when compared to other treatments. Lipid oxidation was also greater in beef from steers fed 30% WDGS (P≤0.05). No significant differences were observed in sensorial attributes and Warner-Bratzler shear force (WBSF) for all muscles (P>0.05). Feeding WDGS increased PUFA and lipid oxidation, which may lead to shorter shelf life., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Cholesterol is a vital component of the human body. It stabilizes cell membranes and is the precursor of bile acids, vitamin D and steroid hormones. However, cholesterol accumulation in the bloodstream (hypercholesterolemia) can cause atherosclerotic plaques within artery walls, leading to heart attacks and strokes. The efficiency of cholesterol absorption in the small intestine is of great interest because human and animal studies have linked cholesterol absorption with plasma concentration of total and low density lipoprotein cholesterol. Cholesterol absorption is highly regulated and influenced by particular compounds in the food supply. Therefore, it is desirable to learn more about natural food components that inhibit cholesterol absorption so that food ingredients and dietary supplements can be developed for consumers who wish to manage their plasma cholesterol levels by non-pharmacological means. Food components thus far identified as inhibitors of cholesterol absorption include phytosterols, soluble fibers, phospholipids, and stearic acid., Competing Interests: AUTHOR DISCLOSURE STATEMENT The authors declare no conflict of interest.

Chronic intake of high sucrose (HS) diet exacerbates high-fat (HF) diet-induced obesity and its associated metabolic complications. Previously, we have demonstrated that ellagic acid (EA), an abundant polyphenol found in some fruits and nuts, exerts distinct lipid-lowering characteristics in hepatocytes and adipocytes. In this study, we hypothesized that EA supplementation inhibits HS diet-mediated hepatic toxicity and its accompanied metabolic dysregulation. To test this hypothesis, C57BL/6 male mice were randomly assigned to three isocaloric HF diets (41% calories from fat) containing either no-sucrose (HF), high-sucrose (HFHS), or high-sucrose plus EA (HFHS-R) from raspberry seed flour (RSF, equivalent to 0.03% of EA), and fed for 12weeks. The inclusion of EA from RSF significantly improved HFHS diet-mediated dyslipidemia and restored glucose homeostasis levels similar to the HF diet-fed mice. Despite marginal difference in hepatic triglyceride content, the addition of EA substantially reversed the activation of endoplasmic reticulum (ER) stress and oxidative damage triggered by HFHS diet in the liver. These effects of EA were further confirmed in human hepatoma cells by reducing ER stress and reactive oxygen species (ROS) production. Moreover, HFHS-R diet significantly decreased visceral adipocyte hypertrophy and adipose tissue inflammation evidenced by reduced proinflammatory gene expression and macrophage infiltration. In summary, EA supplementation from RSF was effective in reducing HFHS diet-mediated metabolic complication by attenuating hepatic ER and oxidative stresses as well as adipocyte inflammation. Our results suggest that the inclusion of EA in diets may normalize metabolic insults triggered by HS consumption., (Copyright © 2016 Elsevier Inc. All rights reserved.)

We previously demonstrated that Nostoc commune var. sphaeroids Kützing (NO), a blue-green alga (BGA), exerts a hypolipidemic effect in vivo and its lipid extract regulates the expression of genes involved in cholesterol and lipid metabolism in vitro. The objective of this study was to investigate whether the hypolipidemic effect of NO is attributed to an algal lipid or a delipidated fraction in vivo compared with Spirulina platensis (SP). Male C57BL/6J mice were fed an AIN-93M diet containing 2.5% or 5% of BGA (w/w) or a lipid extract equivalent to 5% of BGA for 4 weeks to measure plasma and liver lipids, hepatic gene expression, intestinal cholesterol absorption, and fecal sterol excretion. Plasma total cholesterol (TC) was significantly lower in 2.5% and 5% NO-fed groups, while plasma triglyceride (TG) levels were decreased in the 5% NO group compared with controls. However, neither NO organic extract (NOE) nor SP-fed groups altered plasma lipids. Hepatic mRNA levels of sterol regulatory element-binding protein 2, 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR), carnitine palmitoyltransferase-1α, and acyl-CoA oxidase 1 were induced in 5% NO-fed mice, while there were no significant changes in hepatic lipogenic gene expression between groups. NO, but not NOE and SP groups, significantly decreased intestinal cholesterol absorption. When HepG2 cells and primary mouse hepatocytes were incubated with NOE and SP organic extract (SPE), there were marked decreases in protein levels of HMGR, low-density lipoprotein receptor, and fatty acid synthase. In conclusion, the nonlipid fraction of NO exerts TC and TG-lowering effects primarily by inhibiting intestinal cholesterol absorption and by increasing hepatic fatty acid oxidation, respectively.

Background: Elevated concentrations of LDL cholesterol are associated with the development of atherosclerosis and therefore are considered an important target for intervention to prevent cardiovascular diseases. The inhibition of cholesterol absorption in the small intestine is an attractive approach to lowering plasma cholesterol, one that is addressed by drug therapy as well as dietary supplementation with plant sterols and plant sterol esters (PSEs)., Objective: This study was conducted to test the hypothesis that the cholesterol-lowering effects of PSE require hydrolysis to free sterols (FSs)., Methods: Male Syrian hamsters were fed atherogenic diets (AIN-93M purified diet containing 0.12% cholesterol and 8% coconut oil) to which one of the following was added: no PSEs or ethers (control), 5% sterol stearate esters, 5% sterol palmitate esters (PEs), 5% sterol oleate esters (OEs), 5% sterol stearate ethers (STs; to mimic nonhydrolyzable PSE), or 3% FSs plus 2% sunflower oil. The treatments effectively created a spectrum of PSE hydrolysis across which cholesterol metabolism could be compared. Metabolic measurements included cholesterol absorption, plasma and liver lipid concentration, and fecal neutral sterol and bile acid excretion., Results: The STs and the PEs and SEs were poorly hydrolyzed (1.69-4.12%). In contrast, OEs were 88.3% hydrolyzed. The percent hydrolysis was negatively correlated with cholesterol absorption (r = -0.85; P < 0.0001) and positively correlated with fecal cholesterol excretion (r = 0.92; P < 0.0001), suggesting that PSE hydrolysis plays a central role in the cholesterol-lowering properties of PSE., Conclusions: Our data on hamsters suggest that PSE hydrolysis and the presence of FSs is necessary to induce an optimum cholesterol-lowering effect and that poorly hydrolyzed PSEs may lower cholesterol through an alternative mechanism than that of competition with cholesterol for micelle incorporation., (© 2015 American Society for Nutrition.)

Egg yolk contains bioactive components that improve plasma inflammatory markers and HDL profiles in metabolic syndrome (MetS) under carbohydrate restriction. We further sought to determine whether egg yolk intake affects peripheral blood mononuclear cell (PBMC) inflammation and cholesterol homeostasis in MetS, as HDL and its associated lipid transporter ATP-binding cassette transporter A1 (ABCA1) reduce the inflammatory potential of leukocytes through modulation of cellular cholesterol content and distribution. Thirty-seven men and women classified with MetS consumed a moderate carbohydrate-restricted diet (25%-30% of energy) for 12 weeks, in addition to consuming either three whole eggs per day (EGG) or the equivalent amount of yolk-free egg substitute (SUB). Interestingly, lipopolysaccharide-induced PBMC IL-1β and TNFα secretion increased from baseline to week 12 in the SUB group only, despite increases in PBMC toll-like receptor 4 (TLR4) mRNA expression in the EGG group. Compared to baseline, ABCA1 and 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase mRNA expression increased by week 12 in the EGG group only, whereas changes in PBMC total cholesterol positively correlated with changes in lipid raft content. Together, these findings suggest that intake of whole eggs during carbohydrate restriction alters PBMC inflammation and cholesterol homeostasis in MetS.

Background: Obesity rates in the United States have risen consistently over the last four decades, increasing from about 13% of the population in 1970 to more than 34% in 2009. Dietary fructose has been blamed as a possible contributor to the obesity increase, although the consumption pattern of fructose and other key nutrients during this 40 year period remains a topic of debate. Therefore, we analyzed the USDA Loss-Adjusted Food Availability Database in combination with the USDA Nutrient Database for Standard Reference (Release 24) to determine whether fructose consumption in the US has increased sufficiently to be a casual factor in the rise in obesity prevalence., Methods: Per capita loss-adjusted food availability data for 132 individual food items were compiled and analyzed. Nutrient profiles for each of these foods were used to determine the availability of energy as well as macronutrients and monosaccharides during the years 1970-2009. The percent change in energy from food groups and individual nutrients was determined by using the year 1970 as the baseline and area-under-the-curve analysis of food trends., Results: Our findings indicate that during this 40 year period the percent change in total energy availability increased 10.7%, but that the net change in total fructose availability was 0%. Energy available from total glucose (from all digestible food sources) increased 13.0%. Furthermore, glucose availability was more than 3-times greater than fructose. Energy available from protein, carbohydrate and fat increased 4.7%, 9.8% and 14.6%, respectively., Conclusions: These data suggest that total fructose availability in the US did not increase between 1970 and 2009 and, thus, was unlikely to have been a unique causal factor in the increased obesity prevalence. We conclude that increased total energy intake, due to increased availability of foods providing glucose (primarily as starch in grains) and fat, to be a significant contributor to increased obesity in the US.

Dietary consumption of phytosterols and certain fatty acids has been shown to reduce cholesterol absorption and plasma cholesterol concentrations. However, it has not been fully elucidated whether phytosterols or fatty acids can alter the expression of cholesterol transporters by functioning as signaling molecules. This study tested the hypothesis that various fatty acids and phytosterols commonly found in the food supply can modulate the expression of transporters including Niemann-Pick C1-like 1, low-density lipoprotein receptor, and scavenger receptor class B type I and 3-hydroxy-3-methylglutaryl-coenzyme A reductase in the intestine and liver. Caco-2 cells were used as models of enterocytes, and HepG2 cells were used as a model of hepatocytes. The cells were treated for 18 hours with 100 μmol/L of a fatty acid, or for 24 hours with 10 μmol/L of 25α-hydroxycholesterol, or 100 μmol/L of cholesterol, sitosterol, and stigmasterol to measure expression of genes involved in cholesterol transport using quantitative real-time polymerase chain reaction. Polyunsaturated fatty acids in Caco-2 cells and sterols in HepG2 cells significantly reduced the messenger RNA expression levels of Niemann-Pick C1-like 1, scavenger receptor class B type I, low-density lipoprotein receptor, and 3-hydroxy-3-methylglutaryl-coenzyme A reductase. Importantly, sitosterol and stigmasterol reduced the messenger RNA levels of genes to a similar extent as cholesterol. The data support the hypothesis that unsaturated fatty acid and phytosterols can act as signaling molecules and alter the expression of genes involved in cholesterol transport and metabolism., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The gastrointestinal microbiota affects the metabolism of the mammalian host and has consequences for health. However, the complexity of gut microbial communities and host metabolic pathways make functional connections difficult to unravel, especially in terms of causation. In this study, we have characterized the fecal microbiota of hamsters whose cholesterol metabolism was extensively modulated by the dietary addition of plant sterol esters (PSE). PSE intake induced dramatic shifts in the fecal microbiota, reducing several bacterial taxa within the families Coriobacteriaceae and Erysipelotrichaceae. The abundance of these taxa displayed remarkably high correlations with host cholesterol metabolites. Most importantly, the associations between several bacterial taxa with fecal and biliary cholesterol excretion showed an almost perfect fit to a sigmoidal nonlinear model of bacterial inhibition, suggesting that host cholesterol excretion can shape microbiota structure through the antibacterial action of cholesterol. In vitro experiments suggested a modest antibacterial effect of cholesterol, and especially of cholesteryl-linoleate, but not plant sterols when included in model bile micelles. The findings obtained in this study are relevant to our understanding of gut microbiota-host lipid metabolism interactions, as they provide the first evidence for a role of cholesterol excreted with the bile as a relevant host factor that modulates the gut microbiota. The findings further suggest that the connections between Coriobacteriaceae and Erysipelotrichaceae and host lipid metabolism, which have been observed in several studies, could be caused by a metabolic phenotype of the host (cholesterol excretion) affecting the gut microbiota.

Calf-fed crossbred steers (n = 94) were randomly allocated to 3 dietary treatments (0%, 15%, or 30% wet distillers grains plus solubles, WDGS; DM basis) and fed for 167 d to determine the effects on quality attributes of beef. At 48 h postmortem, marbling score, marbling texture, and marbling distribution were assessed by a USDA grader. After grading, one rib eye slice (longissimus thoracis) »7 mm thick was excised from each carcass, trimmed of subcutaneous fat, and analyzed for fatty acid profile and lipid content. At 7 d postmortem, 48 top blades (infraspinatus), strip loins (longissimus lumborum), and tenderloins (psoas major) (16 per treatment) were removed from shoulder clods and short loins and 2 steaks were obtained to measure mineral content, fatty acid profile (except strip loins), trained sensory analysis, objective color, and lipid oxidation. Finishing diet did not influence the content of total lipid (P = 0.19) or marbling, marbling texture, or marbling distribution (P = 0.46, 0.84, 0.40, respectively). Feeding WDGS created a linear increase (P < 0.01) of PUFA in all three muscles (longissimus thoracis showed 4.90%, 5.91%, and 6.23% PUFA for 0%, 15%, and 30% WDGS, respectively). Similar responses were observed for 18:2(n-6) and total n-6 fatty acids. Conversely, lower proportions of 18:1(n-7) fatty acid were observed in beef from animals fed 30% WDGS (P < 0.01). Total trans fatty acids increased linearly in strip loin and top blade steaks (P < 0.01), whereas proportions of 16:0 and 14:1(n-5) fatty acids decreased in all muscles (P < 0.01) as WDGS increased. Diet did not affect mineral content of top blades or strip loins. For tenderloin steaks, S concentration was lower when 30% of WDGS was fed (P = 0.05). No effects on sensory attributes and Warner-Bratzler shear force were observed (P > 0.50), except a minimal effect on strip loin juiciness (5.32, 4.86, and 5.52 for 0%, 15%, and 30% WDGS, respectively; P = 0.02). Top blade and tenderloin steaks from cattle fed 30% WDGS were significantly less red (lower a* values) on d 3 of simulated retail display (P < 0.04). Inclusion of 30% WDGS in the diet resulted in higher levels of oxidation after 7 d of retail display for top blade and strip loin steaks (P < 0.01). Feeding WDGS to calf-fed steers altered fatty acid profile, increased oxidation, and decreased color stability during retail display.

Wet distillers grains contain approximately 65% moisture. A partially dried product [modified distillers grains plus solubles (MDGS)] contains about 50% moisture. However, both have similar nutrient composition on a dry matter basis. The objective of this study was to investigate the effects of finishing diets varying in concentration of MDGS on marbling attributes, proximate composition, and fatty acid profile of beef. Yearling steers (n = 268) were randomly allotted to 36 pens, which were assigned randomly to 0, 10, 20, 30, 40 and 50% MDGS (DM basis) and fed for 176 d before harvest. The 48-h postmortem marbling score, marbling texture, and marbling distribution were assessed by a USDA grader and 1 ribeye slice (longissimus thoracis) 7 mm thick was collected from each carcass for proximate and fatty acid analyses. Treatments did not significantly alter marbling score or marbling distribution (P ≥ 0.05). United States Department of Agriculture Choice slices had coarser marbling texture when compared with USDA Select. Although dietary treatment affected marbling texture, no consistent pattern was evident. Diets did not influence fat content, moisture, or ash of the ribeye (P ≥ 0.05). For treatments 0, 10, 30, 40 and 50%, there were positive linear relationships between marbling score and fat percentage in the ribeye (P ≤ 0.05), and all slopes were similar (P = 0.45). Feeding MDGS linearly increased stearic, linoelaidic, linoleic, linolenic, PUFA, and n-6 fatty acids. As dietary MDGS increased, linear decreases were observed in all n-7 fatty acids and cubic relationships were detected for the 18:1 trans isomers [trans-6-8-octadecenoic acid (6-8t), elaidic acid (9t), trans-10-octadecenoic acid (10t), and trans vaccenic acid (11t)]. No effects were observed for saturated fatty acids containing 6 to 14 carbons. Feeding MDGS resulted in increased PUFA, trans, and n-6 fatty acids, minimal effects on marbling texture, and no effects on the relationship of marbling to intramuscular fat content relationship.

Unrefined and refined black raspberry seed oils (RSOs) were examined for their lipid-modulating effects in male Syrian hamsters fed high-cholesterol (0.12% g/g), high-fat (9% g/g) diets. Hamsters fed the refined and the unrefined RSO diets had equivalently lower plasma total cholesterol and high-density lipoprotein (HDL) cholesterol in comparison with the atherogenic coconut oil diet. The unrefined RSO treatment group did not differ in liver total and esterified cholesterol from the coconut oil-fed control animals, but the refined RSO resulted in significantly elevated liver total and esterified cholesterol concentrations. The unrefined RSO diets significantly lowered plasma triglycerides (46%; P=.0126) in comparison with the coconut oil diet, whereas the refined RSO only tended to lower plasma triglyceride (29%; P=.1630). Liver triglyceride concentrations were lower in the unrefined (46%; P=.0002) and refined (36%; P=.0005) RSO-fed animals than the coconut oil group, with the unrefined RSO diet eliciting a lower concentration than the soybean oil diet. Both RSOs demonstrated a null or moderate effect on cholesterol metabolism despite enrichment in linoleic acid, significantly lowering HDL cholesterol but not non-HDL cholesterol. Dramatically, both RSOs significantly reduced hypertriglyceridemia, most likely due to enrichment in α-linolenic acid. As a terrestrial source of α-linolenic acid, black RSOs, both refined and unrefined, provide a promising alternative to fish oil supplementation in management of hypertriglyceridemia, as demonstrated in hamsters fed high levels of dietary triglyceride and cholesterol.

The dietary impact of specific phytosterols incorporated into phytosterol fatty acid esters has not been elucidated. Therefore, we tested the hypothesis that phytosterol esters containing different sterol moieties (sitosterol, sitostanol, or stigmasterol) but the same fatty acid moiety (stearic acid) produce different effects on cholesterol metabolism. Male Syrian hamsters were fed sitosterol, sitostanol, and stigmasterol stearate esters (25 g/kg diet) in an atherogenic diet containing cholesterol (1.2 g/kg) and coconut oil (80 g/kg). The phytosterol stearates produced no decrease in cholesterol absorption or plasma non-high-density lipoprotein cholesterol despite a reduction in liver free cholesterol in hamsters fed both sitosterol and sitostanol stearate diets. In addition, sitosterol stearate significantly increased fecal esterified and total neutral sterol excretion. Stigmasterol stearate did not differ from control in neutral sterol excretion, plasma lipids, or hepatic lipid concentration. Sitosterol stearate demonstrated the highest level of net intestinal hydrolysis, whereas sitostanol and stigmasterol stearate equivalently demonstrated the lowest. The cholesterol-lowering effect in liver-but not plasma-and the limited presence of fecal free sterols indicate that intact (unhydrolyzed) phytosterol stearates may impact cholesterol metabolism by mechanisms unrelated to the role of free phytosterols. The consumption of phytosterol esters at 2.5% of the diet elicited only modest impacts on cholesterol metabolism, although sitosterol stearate had a slightly greater therapeutic impact by lowering liver free cholesterol and increasing esterified and total neutral sterol fecal excretion, possibly due to a greater level of intestinal hydrolysis., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Little is known about patients prescribed high doses of opioids to treat chronic non-cancer pain, though these patients may be at higher risk for medication-related complications. We describe the prevalence of high-dose opioid use and associated demographic and clinical characteristics among veterans treated in a VA regional healthcare network. Veterans with chronic non-cancer pain prescribed high doses of opioids (≥ 180 mg/day morphine equivalent; n=478) for 90+ consecutive days were compared to two groups with chronic pain: Traditional-dose (5-179 mg/day; n=500) or no opioid (n=500). High-dose opioid use occurred in 2.4% of all chronic pain patients and in 8.2% of all chronic pain patients prescribed opioids long-term. The average dose in the high-dose group was 324.9 (SD=285.1)mg/day. The only significant demographic difference among groups was race (p=0.03) with black veterans less likely to receive high doses. High-dose patients were more likely to have four or more pain diagnoses and the highest rates of medical, psychiatric, and substance use disorders. After controlling for demographic factors and VA facility, neuropathy, low back pain, and nicotine dependence diagnoses were associated with increased likelihood of high-dose prescriptions. High-dose patients frequently did not receive care consistent with treatment guidelines: there was frequent use of short-acting opioids, urine drug screens were administered to only 25.7% of patients in the prior year, and 32.0% received concurrent benzodiazepine prescriptions, which may increase risk for overdose and death. Further study is needed to identify better predictors of high-dose usage, as well as the efficacy and safety of such dosing., (Published by Elsevier B.V.)

Plant sterols and stanols (phytosterols) and their esters are nutraceuticals that lower LDL cholesterol, but the mechanisms of action are not fully understood. We hypothesized that intact esters and simulated hydrolysis products of esters (phytosterols and fatty acids in equal ratios) would differentially affect the solubility of cholesterol in model bile mixed micelles in vitro. Sodium salts of glycine- and taurine-conjugated bile acids were sonicated with phosphatidylcholine and either sterol esters or combinations of sterols and fatty acids to determine the amount of cholesterol solubilized into micelles. Intact sterol esters did not solubilize into micelles, nor did they alter cholesterol solubility. However, free sterols and fatty acids altered cholesterol solubility independently (no interaction effect). Equal contents of cholesterol and either campesterol, stigmasterol, sitosterol, or stigmastanol (sitostanol) decreased cholesterol solubility in micelles by approximately 50% compared to no phytosterol present, with stigmasterol performing slightly better than sitosterol. Phytosterols competed with cholesterol in a dose-dependent manner, demonstrating a 1:1 M substitution of phytosterol for cholesterol in micelle preparations. Unsaturated fatty acids increased the micelle solubility of sterols as compared with saturated or no fatty acids. No differences were detected in the size of the model micelles. Together, these data indicate that stigmasterol combined with saturated fatty acids may be more effective at lowering cholesterol micelle solubility in vivo.

Consumption of plant sterols or stanols (collectively referred to as phytosterols) and their esters results in decreased low-density lipoprotein cholesterol, which is associated with decreased atherosclerotic risk. The mechanisms by which phytosterols impart their effects, however, are incompletely characterized. The objective of the present study is to determine if pancreatic cholesterol esterase (PCE; EC 3.1.1.13), the enzyme primarily responsible for cholesterol ester hydrolysis in the digestive tract, is capable of hydrolyzing various phytosterol esters and to compare the rates of sterol ester hydrolysis in vitro. We found that PCE hydrolyzes palmitate, oleate and stearate esters of cholesterol, stigmasterol, stigmastanol and sitosterol. Furthermore, we found that the rate of hydrolysis was dependent on both the sterol and the fatty acid moieties in the following order of rates of hydrolysis: cholesterol>(sitosterol=stigmastanol)>stigmasterol; oleate>(palmitate=stearate). The addition of free phytosterols to the system did not change hydrolytic activity of PCE, while addition of palmitate, oleate or stearate increased activity. Thus, PCE may play an important but discriminatory role in vivo in the liberation of free phytosterols to compete with cholesterol for micellar solubilization and absorption., (Copyright 2010 Elsevier Inc. All rights reserved.)

Intake of plant sterols has long been shown to reduce cholesterol absorption and subsequently plasma cholesterol concentrations. Despite competition between plant sterols and cholesterol for incorporation into mixed micelles as a suggested major mechanism for the inhibition of cholesterol absorption by plant sterols, studies exist to support an alternative mechanism. For example, another mechanism may be the action of plant sterols to reduce cholesterol absorption at the cellular level. This study was undertaken to test the hypothesis that plant sterols can modulate the expression of transporters such as Niemann-Pick C1-like 1 (NPC1L1) and scavenger receptor class B, type I (SR-BI) to lower intestinal cholesterol absorption. FHs 74 Int cells, a human small intestine epithelial cell line, were used as a model of enterocytes. The cells were treated with 25alpha-hydroxycholesterol (25 micromol/L) or 250 micromol/L of sitosterol, stigmasterol, and cholesterol for 24 hours to measure genes involved in cholesterol absorption and metabolism by quantitative real-time polymerase chain reaction. 25Alpha-hydroxycholesterol, cholesterol, and sitosterol significantly reduced the messenger RNA (mRNA) expression of NPC1L1 and hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, whereas SR-BI mRNA was not altered by the sterols. Western blot analysis confirmed the reduction in NPC1L1 by sterols. Depletion of cellular cholesterol by mevinolin, a cholesterol synthesis inhibitor, increased NPC1L1 and HMG-CoA reductase mRNA; and repletion of cholesterol abolished the increase. Sitosterol, but not stigmasterol, reduced the mRNA levels of NPC1L1 and HMG-CoA reductase to a similar extent of cholesterol. In conclusion, sitosterol can inhibit the expression of NPC1L1 in the enterocytes, which could be an alternate mechanism for plant sterols to reduce intestinal cholesterol uptake.

Studies in our laboratory have previously demonstrated in hamsters a superior cholesterol-lowering ability of plant sterol (PS) esters enriched in stearate compared with linoleate. We therefore conducted a randomized, double-blind, 2-group parallel, placebo-controlled study to test the cholesterol-lowering properties of stearate-enriched PS esters in normo- and hypercholesterolemic adults. Thirty-two adults, 16 per group with equal number of males and females in each group, participated in the 4-wk study. Participants consumed 3 g/d (1 g three times per day with meals) of either PS esters or placebo delivered in capsules. Serum LDL cholesterol concentration significantly decreased 0.42 mmol/L (11%) and the LDL:HDL cholesterol ratio decreased 10% with PS ester supplementation, whereas LDL particle size and lipoprotein subclass particle concentrations (as measured by NMR) were not affected. The percent change in LDL cholesterol was positively correlated with baseline lathosterol concentration (r = 0.729; P = 0.0014), indicating an association between the magnitude of LDL change and the rate of whole-body cholesterol synthesis. Serum campesterol (but not sitosterol) concentration significantly increased in the PS ester group. Serum tocopherol, retinol, and beta-carotene concentrations were not affected by PS ester supplementation. Thus, our findings demonstrate the usefulness of a novel stearate-enriched PS ester compound in decreasing LDL cholesterol in both normo- and hypercholesterolemic adults. The extent to which PS ester fatty acid composition affects intestinal micelle formation and cholesterol absorption in humans requires further study.

The mammalian gastrointestinal microbiota exerts a strong influence on host lipid and cholesterol metabolism. In this study, we have characterized the interplay among diet, gut microbial ecology, and cholesterol metabolism in a hamster model of hypercholesterolemia. Previous work in this model had shown that grain sorghum lipid extract (GSL) included in the diet significantly improved the high-density lipoprotein (HDL)/non-HDL cholesterol equilibrium (T. P. Carr, C. L. Weller, V. L. Schlegel, S. L. Cuppett, D. M. Guderian, Jr., and K. R. Johnson, J. Nutr. 135:2236-2240, 2005). Molecular analysis of the hamsters' fecal bacterial populations by pyrosequencing of 16S rRNA tags, PCR-denaturing gradient gel electrophoresis, and Bifidobacterium-specific quantitative real-time PCR revealed that the improvements in cholesterol homeostasis induced through feeding the hamsters GSL were strongly associated with alterations of the gut microbiota. Bifidobacteria, which significantly increased in abundance in hamsters fed GSL, showed a strong positive association with HDL plasma cholesterol levels (r = 0.75; P = 0.001). The proportion of members of the family Coriobacteriaceae decreased when the hamsters were fed GSL and showed a high positive association with non-HDL plasma cholesterol levels (r = 0.84; P = 0.0002). These correlations were more significant than those between daily GSL intake and animal metabolic markers, implying that the dietary effects on host cholesterol metabolism are conferred, at least in part, through an effect on the gut microbiota. This study provides evidence that modulation of the gut microbiota-host metabolic interrelationship by dietary intervention has the potential to improve mammalian cholesterol homeostasis, which has relevance for cardiovascular health.

Understanding the endocannabinoid system as it relates to health and disease is a relatively new area of study. The discovery and cloning of cannabinoid receptors have prompted an increase in research aimed at identifying endogenous ligands ("endocannabinoids") and how these receptors and ligands regulate a variety of physiologic and pathologic events that include bone formation, the cardiovascular system, appetite control, and energy metabolism. With regard to nutrition, researchers have begun to ask whether the known effects of diet on metabolic processes are mediated through endocannabinoids and their receptors. Although only a few studies have been conducted that directly address the role of diet, results indicate that endocannabinoids can be regulated by eating frequency and by specific dietary components, particularly fatty acids. This review provides an overview of the endocannabinoid system and its control of metabolism, with emphasis on the impact of diet.

Beef knuckles (n = 160) were obtained from source-verified cattle finished on 30% wet distillers grains plus solubles enriched with varying levels of alfalfa hay (4 or 8%), corn silage (6 or 12%), or corn stalks (3 or 6%) based on NDF. Proximate analysis, pH, oxidation-reduction potential, fatty acid composition, and sensory analysis were conducted on the rectus femoris muscle to determine if roughage inclusion, in conjunction with wet distillers grains plus solubles and cattle source, affects beef flavor with particular interest in liver-like off-flavor. Proximate analysis, fat content, and oxidation-reduction potential were unaffected (P ge;0.129) by diet or source. For s.c. adipose tissue, cattle from Nebraska (NE) had greater amounts of MUFA (P = 0.048) and unsaturated fatty acids (P = 0.068) but less SFA (P = 0.065) when compared with cattle from South Dakota. Diet affected s.c. adipose tissue levels of 15:0, 17:0, and n-3 fatty acids in which cattle from NE finished on the low corn stalk diet had (P < or =0.050) lower levels. Cattle from NE had (P < or = 0.049) greater i.m. adipose proportions of 13:0 and CLA. Dietary effects (P < or = 0.050) were observed for i.m. adipose tissue proportions of 16:0, 18:1(n-9), 18:2(n-6), 20:4(n-6), 22:5(n-3), MUFA, PUFA, and n-6 fatty acids. Sensory analysis revealed that cattle from NE were (P < or = 0.023) less juicy and had less bloody notes when compared with cattle from South Dakota. Cattle finished on the low alfalfa diet were (P < or = 0.014) more tender and juicy but had more bloody notes. No (P ge; 0.670) dietary or source effects were noted for liver-like off-flavor. Subcutaneous amounts of 18:2(n-6 trans) (r = -0.17) were inversely related to the incidence of liver-like off-flavor, whereas 20:1(n-9) (r = 0.21), CLA cis-9, trans-11 (r = 0.16) were directly related. Data from this study indicate that type and level of roughage inclusion and cattle source have minimal effects on fatty acid profiles and sensory properties of the musculus rectus femoris. However, individual fatty acids of s.c. and i.m. adipose tissue were significantly correlated with liver-like off-flavor.

Experiments were carried out on a lab supercritical CO(2) extraction system to determine the effects of extraction conditions, including mass ratio of CO(2) consumed to distillers dry grain with solubles (DDGS) extracted, extraction pressure, extraction temperature and time, on yield and composition of extracted lipids. A maximum lipid yield of 150 g/kg DDGS was achieved with a mass ratio approximately 45, an extraction pressure at 27.5 MPa, an extraction temperature at 70 degrees C and an extraction time of 4 h. Under these extraction conditions, the contents of tocols, phytosterols, policosanols and free fatty acids were 0.44, 15.6, 31.2 and 155.3 mg/g in the extract. Experimental results indicated that shorter extraction time and higher flow rate of CO(2) can achieve higher contents of tocols, phytosterols and policosanols but lower content of free fatty acids in the lipid extract. Extraction conditions had no observed effects on the composition of free fatty acids in the extract. Palmitic, oleic and linoleic acids were three main free fatty acids extracted and constituted about 94% of all free fatty acids.

We investigated whether lipid extract from a blue-green alga, N commune, modulates proinflammatory gene expression in RAW 264.7 macrophages. The cells were incubated with N commune lipid extract (0-100 microg/mL) and subsequently activated by LPS (100 ng/mL). Quantitative real-time PCR analysis showed that mRNA abundance of proinflammatory mediators, including TNF-alpha, COX-2, IL-1beta, IL-6, and iNOS, was significantly reduced by N commune lipid extract in a dose-dependent manner. Secretion of TNF-alpha and IL-1beta into cell culture medium was also significantly decreased by N commune lipid extract. Thin-layer chromatography-densitometry analysis showed that N commune lipid extract contained approximately 15% of fatty acids. To determine whether the inhibition of proinflammatory mediator production by N commune lipid extract is primarily conferred by fatty acids in the lipid extract, macrophages were incubated with 100 microg/mL of N commune lipid extract or 15 microg/mL of a fatty acid mixture, which was formulated to reflect the fatty acid composition of N commune lipid extract. The fatty acid mixture significantly reduced RNA abundance of TNF-alpha and COX-2, but to a lesser extent than did the N commune lipid extract, suggesting the presence of additional bioactive compounds with an antiinflammatory property in the lipid extract. As NF-kappaB is a major regulator for the proinflammatory gene expression, we measured its DNA-binding activity. DNA-binding activity of NF-kappaB was significantly reduced by N commune lipid extract. In conclusion, our study suggests that N commune lipid extract represses the expression of proinflammatory genes in RAW 264.7 macrophages, at least in part, by inhibiting the activation of NF-kappaB pathway.

Consumption of plant sterol esters reduces plasma LDL cholesterol concentration by inhibiting intestinal cholesterol absorption. Commercially available plant sterol esters are prepared by esterifying free sterols to fatty acids from edible plant oils such as canola, soybean, and sunflower. To determine the influence of the fatty acid moiety on cholesterol metabolism, plant sterol esters were made with fatty acids from soybean oil (SO), beef tallow (BT), or purified stearic acid (SA) and fed to male hamsters for 4 wk. A control group fed no plant sterol esters was also included. Hamsters fed BT and SA had significantly lower cholesterol absorption and decreased concentrations of plasma non-HDL cholesterol and liver esterified cholesterol, and significantly greater fecal sterol excretion than SO and control hamsters. Cholesterol absorption was lowest in hamsters fed SA (7.5%), whereas it was 72.9% in control hamsters. Cholesterol absorption was correlated with fecal sterol excretion (r = -0.72, P < 0.001), liver cholesterol concentration (r = 0.88, P < 0.001), and plasma non-HDL cholesterol concentration (r = 0.85, P < 0.001). A multiple regression model that included each sterol ester type vs. cholesterol absorption indicated that intake of steryl stearate was the only dietary component that contributed significantly to the model (R2 = -0.75, P < 0.001). Therefore, our results demonstrate that BT and SA are more effective than SO in reducing cholesterol absorption, liver cholesterol, and plasma non-HDL cholesterol concentration, suggesting that cardioprotective benefits can be achieved by consuming stearate-enriched plant sterol esters.

Grain sorghum is a rich source of phytochemicals that could potentially benefit human health. In this study, male hamsters were fed AIN-93M diets supplemented with a hexane-extractable lipid fraction from grain sorghum whole kernels. The grain sorghum lipids (GSL) comprised 0.0, 0.5, 1.0, or 5.0% of the diet by weight. After 4 wk, dietary GSL significantly reduced plasma non-HDL cholesterol concentration in a dose-dependent manner with reductions of 18, 36, and 69% in hamsters fed 0.5, 1.0, and 5.0% GSL, respectively, compared with controls. Liver cholesteryl ester concentration was also significantly reduced in hamsters fed GSL. Plasma HDL cholesterol concentration was not altered (P > 0.05) by dietary treatment. Cholesterol absorption efficiency was significantly reduced by GSL in a dose-dependent manner. Cholesterol absorption was also directly correlated with plasma non-HDL cholesterol concentration (r = 0.97, P < 0.05), suggesting that dietary GSL lowers non-HDL cholesterol, at least in part, by inhibiting cholesterol absorption. TLC and GLC analyses of the GSL extract revealed the presence of plant sterols and policosanols at concentrations of 0.35 and 8.0 g/100 g GSL, respectively. Although plant sterols reduce cholesterol absorption, policosanols may inhibit endogenous cholesterol synthesis. The data suggest that these components of GSL extract may work collectively in lowering plasma and liver cholesterol concentrations. Our findings further indicate that grain sorghum contains beneficial components that could be used as food ingredients or dietary supplements to manage cholesterol levels in humans.

This study was conducted to determine the secretion rate and composition of lipoproteins secreted by HepG2 cells as influenced by the type of fatty acid present in the incubation medium. Cells were preincubated for 24 h with palmitic, oleic, elaidic, linoleic or conjugated linoleic acid (CLA), and the lipoproteins secreted during a subsequent incubation period of 24 h were collected for analysis. The secretion rate of apolipoprotein B-100 (apoB) was significantly greater in HepG2 cells preincubated with elaidic acid compared with those preincubated with palmitic or oleic acid; apoB secretion was greater in cells preincubated with CLA compared with those preincubated with linoleic acid. The lipid composition of secreted lipoproteins was also influenced by fatty acid treatment, resulting in significantly smaller lipoprotein particles secreted by cells preincubated with elaidic acid and CLA compared with those secreted by cells treated with oleic acid and linoleic acid, respectively. Our results are relevant to human metabolism for the following reasons: (1) the size of plasma low-density lipoproteins (LDLs) is determined, at least in part, by the composition of apoB-containing lipoproteins secreted by the liver; (2) small plasma LDL particles are associated with an increased risk of coronary heart disease; and (3) specific dietary fatty acids can affect the composition and size of plasma LDLs, thereby imparting a relative atherogenicity to plasma LDLs independent of LDL cholesterol concentration. The present study therefore suggests that elaidic acid and CLA promote the hepatic secretion of small apoB-containing lipoproteins, which could lead to an increased production of small plasma LDL particles.

To investigate the effects of dietary fatty acids on acyl-CoA:cholesterol acyltransferase (ACAT) and cytosolic cholesteryl ester hydrolase (cCEH), male Syrian hamsters (F(1)B hybrid) were fed a modified version of the NIH-07 open formula, cereal-based rodent diet enriched with one of the following 4 dietary fatty acids: palmitic acid (16:0), trans fatty acids (18:1t), oleic acid (18:1c), or linoleic acid (18:2). Hamsters fed 16:0 and 18:1t had significantly higher plasma non-HDL cholesterol concentrations compared with those fed 18:1c and 18:2. However, differences in plasma apolipoprotein (apo)B(100) concentration, hepatic cCEH mRNA abundance, and hepatic ACAT activity between 16:0- and 18:1t-fed hamsters suggest that the hypercholesterolemic effects are achieved by different mechanisms. Specifically, an increase in ACAT activity by 16:0 may induce enrichment of cholesteryl esters in apoB(100)-containing particles, whereas 18:1t may increase the number of the particles. Hepatic cholesteryl esters accumulated in the 18:1c- and 18:2-fed groups with no differences in hepatic ACAT activity and cCEH mRNA abundance among hamsters fed unsaturated fatty acids (i.e., 18:1t, 18:1c, and 18:2). Considering the lack of change in free cholesterol concentration and increased cholesteryl esters in the liver, the hypocholesterolemic effect of 18:1c and 18:2 compared with 18:1t may be attributed to decreased production of apoB(100)-containing particles. ACAT-1 was expressed in all the tissues examined; in contrast, ACAT-2 was highly expressed in the liver and small intestine. Hepatic ACAT activity was disproportionate to the levels of ACAT-1 and ACAT-2 mRNA and protein, indicating post-transcriptional regulation of ACAT by dietary fatty acids. The data suggest that cholesterolemic effects of individual dietary fatty acids can be achieved through their independent modulation of pathways regulating assembly and secretion of apoB(100)-containing particles.

Dietary stearic acid (18:0) lowers plasma and liver cholesterol concentration by reducing intestinal cholesterol absorption. We tested the hypothesis that dietary 18:0 reduces cholesterol absorption by altering hepatic bile acid synthesis and gallbladder bile acid composition. Male Syrian hamsters were fed modified NIH-07 open formula diets, enriched (5 g/100 g diet) in one of the following fatty acids: 18:0, palmitic acid (16:0), trans fatty acids (18:1t), oleic acid (18:1c) or linoleic acid (18:2). After 18 wk, gallbladders were removed and bile acid composition determined by HPLC. The distribution of primary bile acids (mol/100 mol) was unaffected by treatment. In contrast, dietary 18:0 significantly reduced the proportion of hydrophobic secondary bile acids, resulting in a lower hydrophobicity index of the bile. These data suggest that reduced cholesterol absorption by dietary 18:0 is due, at least in part, to reduced cholesterol solubility. The data further suggest that 18:0 may have altered the microflora populations that synthesize secondary bile acids. Although cholesterol 7alpha-hydroxylase (CYP7A1) activity was significantly higher in hamsters fed 18:0 compared with 16:0, this finding is most likely due to increased fecal bile acid output in the 18:0 group rather than transcriptional regulation of CYP7A1 by 18:0 or specific bile acids.

Objective: Both chitosan and glucomannan have demonstrated hypocholesterolemic effects. A recent study in rats indicates that the combination of the two is also a potent hypocholesterolemic agent that increases fecal fat excretion. The objective of the present study was to determine the hypocholesterolemic effect of a supplement containing equal amounts of chitosan and glucomannan on blood lipid concentrations and fecal excretion of fat, neutral sterols and bile acids., Methods: Twenty-one overweight normocholesterolemic subjects (11 males and 10 females) were fed 2.4 g/day of a supplement containing equal amounts of chitosan and glucomannan. Prior to taking the supplement (initial period) and after 28 days (final period), blood was drawn for measurement of serum lipids and a three-day fecal sample collected for determination of fat, neutral sterol and bile acid excretion. Subjects maintained their normal dietary and activity patterns during the study., Results: Caloric intake and intake of fat and dietary fiber (excluding the supplement) did not differ between the initial and final periods. Serum total, HDL and LDL cholesterol concentrations were significantly lower (p < 0.05) in the final period compared to the initial period. Serum triacylglycerol concentration did not change between periods. There was a trend towards greater fecal excretion of neutral sterols and bile acids (p = 0.13 and 0.16, respectively) in the final period. However, fecal fat excretion did not differ between periods., Conclusions: Serum cholesterol reduction by a chitosan/glucomannan supplement is likely mediated by increased fecal steroid excretion and is not linked to fat excretion.

Background: Soy consumption is known to reduce plasma total cholesterol and LDL cholesterol in hypercholesterolemic subjects, but the responsible soy components and the effects in normocholesterolemic subjects remain unclear., Objective: The effects of soy isoflavone consumption on plasma total cholesterol, HDL-cholesterol, LDL-cholesterol, triacylglycerol, apolipoprotein A-I, apolipoprotein B, and lipoprotein(a) concentrations and on LDL peak particle diameter were examined in normocholesterolemic, premenopausal women., Design: Thirteen healthy, normocholesterolemic, free-living, premenopausal female volunteers took part in this randomized, crossover-controlled trial. Each subject acted as her own control. Three soy isoflavone intakes (control: 10.0 +/- 1.1; low: 64.7 +/- 9.4; and high: 128.7 +/- 15.7 mg/d), provided as soy protein isolate, were consumed for 3 menstrual cycles each. Total cholesterol, HDL cholesterol, LDL cholesterol, and triacylglycerol were measured over the menstrual cycle. Apolipoprotein A-I, apolipoprotein B, lipoprotein(a), and LDL peak particle diameter were evaluated in the midluteal phase., Results: Total cholesterol, HDL-cholesterol, and LDL-cholesterol concentrations changed significantly across menstrual cycle phases (P < 0.005). During specific phases of the cycle, the high-isoflavone diet lowered LDL cholesterol by 7.6-10.0% (P < 0.05), the ratio of total cholesterol to HDL cholesterol by 10.2% (P < 0.005), and the ratio of LDL to HDL cholesterol by 13.8% (P < 0.002)., Conclusions: Isoflavones significantly improved the lipid profile across the menstrual cycle in normocholesterolemic, premenopausal women. Although of small magnitude, these effects could contribute to a lower risk of developing coronary heart disease in healthy people who consume soy over many years.

The observation that dietary stearic acid does not raise plasma cholesterol concentration is well documented, although the regulating mechanisms are not completely understood. Therefore, we examined the effect of dietary stearic acid on cholesterol absorption and sterol balance using male Syrian hamsters fed modified NIH-07 cereal-based diets selectively enriched in palmitic acid (16:0), stearic acid (18:0), trans fatty acid (18:1t), cis oleic acid (18:1c) or linoleic acid (18:2). All diets contained 17 g/100 g total fat and 0.05 g/100 g cholesterol; the five fat blends were enriched 30% with the fatty acid of interest above a constant fatty acid background. Cholesterol absorption efficiency was 50-55% in all treatment groups except for the 18:0 group, in which cholesterol absorption was significantly reduced to 21%. Plasma total cholesterol concentration was significantly lower in the 18:0 group compared to the 16:0 group. Fecal neutral steroid excretion was significantly greater in hamsters fed the high 18:0 diet compared to the other treatment groups. After accounting for unabsorbed dietary cholesterol, endogenous cholesterol excretion was about 100% higher in the 18:0 group. Consequently, the calculated rate of whole body cholesterol synthesis was significantly increased by dietary 18:0. Bile acid excretion accounted for only 12-20% of total sterol output by the hamsters in this study. Thus, the data suggest that reduced plasma cholesterol concentration in hamsters fed high 18:0 diets may be influenced by reduced cholesterol absorption and increased excretion of endogenous cholesterol.

Male Syrian hamsters were fed 0.02, 0.03, or 0.05% cholesterol to test the hypothesis that moderate cholesterol intake increases the cholesteryl ester content of the plasma low-density lipoproteins (LDL). Dietary cholesterol levels of 0.02%-0.05% were chosen to reflect typical human intakes of cholesterol. Hamsters were fed ad libitum a cereal-based diet (modified NIH-07 open formula) for 15 weeks. Increasing dietary cholesterol from 0.02% to 0.05% resulted in significantly increased plasma LDL and high-density lipoprotein cholesterol concentration, increased liver cholesterol concentration, and increased total aorta cholesterol content. The cholesteryl ester content of plasma LDL was determined as the molar ratio of cholesteryl ester to apolipoprotein B and to surface lipid (i.e., phospholipid + free cholesterol). Increasing dietary cholesterol from 0.02% to 0.05% resulted in significantly increased cholesteryl ester content of LDL particles. Furthermore, cholesteryl ester content of LDL was directly associated with increased total aorta cholesterol, whereas a linear relationship between plasma LDL cholesterol concentration and aorta cholesterol was not observed. Thus, the data suggest that LDL cholesteryl ester content may be an important atherogenic feature of plasma LDL.

The major compensatory responses to increased cholesterol consumption are decreased cholesterol synthesis and increased cholesterol excretion through the bile either as free cholesterol or bile acids. The objective of this study was to test the hypothesis that biliary cholesterol excretion is increased in hamsters fed low levels of cholesterol reflecting normal human intake. The hypothesis was based on observations that hamsters generally resist changes in bile acid synthesis when fed large amounts of cholesterol; therefore, increased biliary cholesterol excretion represents a potentially significant pathway for elimination of excess cholesterol in this species. Hamsters were fed modified NIH-07 cereal-based diets containing 0.02%, 0.03%, and 0.05% cholesterol (0.04, 0.06, and 0.10 mg cholesterol/kcal, respectively). The primary response to increasing amounts of dietary cholesterol was downregulation of whole-body cholesterol synthesis, reduced from 3.93+/-0.14 micromol x d(-1) x 100 g(-1) body weight in hamsters fed 0.02% cholesterol to 0.52+/-0.14 micromol x d(-1) x 100 g(-1) in the 0.05% cholesterol group. Biliary cholesterol excretion was also slightly reduced in hamsters fed 0.05% cholesterol, whereas bile acid excretion was not altered by dietary cholesterol. Despite a pronounced downregulation of whole-body cholesterol synthesis, liver and plasma cholesterol concentrations increased in hamsters fed 0.05% cholesterol. The data indicate that increased biliary cholesterol excretion is not a major compensatory route of cholesterol excretion in hamsters consuming cholesterol. Furthermore, cholesterol added to the diet at 0.05% appears to be the approximate threshold at which compensatory mechanisms can prevent increases in liver and plasma cholesterol in male Syrian hamsters. Consequently, this species may be an appropriate animal model for "hyperresponding" individuals in the human population.

Objective: In an attempt to improve the nutritional value of animal fats (including milkfat and lard), two technological approaches (i.e., cholesterol removal by steam distillation and linoleic acid enrichment by addition of safflower oil) were tested for cholesterolemic effects in a cohort of 29 older women (age 68 +/- 7 years)., Methods: Test fat sources were incorporated into crackers, cookies, cheese, ice cream, whipped topping, sour cream, baking shortening, and table spreads. Subjects were permanent residents of a convent where meals were prepared in a centralized kitchen, allowing test fats to be provided in daily food menu items. The foods containing test fats were introduced into three sequential dietary treatment periods, each lasting 4 weeks, in the following order: cholesterol-reduced animal fat (CRAF): fatty-acid modified, cholesterol-reduced animal fat (FAMCRAF); and-unaltered animal fat (AF). Subjects were offered menu items cafeteria style and encouraged to make food selections consistent with their habitual diets, which were recorded daily., Results: Fasted blood lipid profiles determined at the end of each treatment period showed that FAMCRAF reduced mean plasma total cholesterol, LDL cholesterol, and apolipoprotein B concentrations relative to AF (p < 0.05). Mean HDL cholesterol concentrations were not influenced by diet., Discussion: Relative to native products, animal fats modified by cholesterol removal and linoleic acid enrichment reduced plasma total and LDL cholesterol concentrations in a predictable manner similar to that based on studies of men.

Relationships among plasma lipoprotein cholesterol, cholesterol secretion by the isolated, perfused liver, and coronary artery atherosclerosis were examined in African green monkeys fed diets containing cholesterol and 35% of calories as fat enriched in polyunsaturated, monounsaturated, or saturated fatty acids. The livers of animals fed monounsaturated fat had significantly higher cholesteryl ester concentrations (8.5 mg/g wet wt) than the livers of the other diet groups (3.65 and 3.37 mg/g wet wt for saturated and polyunsaturated fat groups, respectively) and this concentration was highly correlated with plasma cholesterol and apoB concentrations in each diet group. Cholesteryl oleate was 58 and 74. 5% of the liver cholesteryl ester in the saturated and monounsaturated fat groups. In each diet group, perfusate cholesteryl ester accumulation rate was highly correlated to liver and plasma cholesterol concentrations, and to plasma LDL cholesteryl ester content. Cholesteryl oleate was 48 and 67% of the cholesteryl esters that accumulated in perfusate in the saturated and monounsaturated fat animals, and this percentage was very highly correlated (r = -0.9) with plasma apoB concentration. Finally, in these two diet groups, liver perfusate cholesteryl ester accumulation rate was well correlated (r >/= 0.8) to coronary artery cholesteryl ester concentration, a measure of the extent of coronary artery atherosclerosis that occurred over the five years of diet induction in these animals. These data define an important role for the liver in the cholesteryl oleate enrichment of the plasma lipoproteins in the saturated and monounsaturated fat groups, and demonstrate strong relationships among hepatic cholesteryl ester concentration, cholesteryl ester secretion, and LDL particle cholesteryl ester content. The high correlation between liver cholesteryl ester secretion and coronary artery atherosclerosis provides the first direct demonstration of the high degree of importance of hepatic cholesteryl ester secretion in the development of this disease process. The remarkable degree of enrichment of cholesteryl oleate in plasma cholesteryl esters of the monounsaturated fat group may account for the relatively high amount of coronary artery atherosclerosis in this group.

This study was conducted to test the hypothesis that increased intestinal contents viscosity lowers plasma cholesterol concentrations by decreasing cholesterol absorption. Male Golden Syrian hamsters were fed for 4 wk diets containing 0.12% cholesterol, and either 4% cellulose or four different viscosity grades of hydroxypropyl methylcellulose (HPMC). Dietary HPMC confers viscosity in the small intestine but is resistant to fermentation. Cholesterol absorption efficiency was measured using the dual isotope ratio method, and plasma and liver cholesterol concentrations were determined enzymatically. Ex vivo viscosity of intestinal contents supernatants was measured using a Wells-Brookfield cone/plate viscometer, and the means of treatment groups ranged from 6 to 6532 mPa.s. Relative to dietary cellulose, all viscosity grades of HPMC resulted in significantly lower cholesterol absorption efficiency, lower plasma cholesterol concentration, and lower liver cholesteryl ester content. The logarithm of intestinal contents ex vivo viscosity was inversely correlated with dietary cholesterol absorption (r2 = 0.84, P = 0.028). Furthermore, dietary cholesterol absorption was positively correlated with plasma cholesterol concentration (r2 = 0.89, P = 0.017) and liver cholesteryl ester content (r2 = 0.96, P = 0.0031). Thus, the data suggest an independent role of intestinal contents viscosity in lowering plasma cholesterol concentration and liver cholesteryl ester content by reducing cholesterol absorption efficiency.

New atherosclerosis causative factors and preventive modalities have been identified. Atherogenic factors include lipid oxidation products, such as cholesterol oxidation products, malonaldehyde and other aldehydes; trans-fatty acids; some saturated fatty acids (lauric, myristic and possibly palmitic acids); and myristic acid plus cholesterol. Lipid oxidation products are well suited to induce arterial damage, based on their known cytotoxic effects; evidence also indicates the possibility of plaque promotion and stimulation of thrombogenesis. Anti-atherogenic factors include antioxidants, fish oils and other polyunsaturates (if protected from oxidation), fibre and trace minerals such as copper, manganese, selenium and zinc. Iron is unique, being considered as both a potential promoter of atherosclerosis (component of ferritin, conceivably inducing lipid oxidation) and a possible anti-atherogenic component (of antioxidant enzyme catalase). It is apparent that an entire new series of research challenges has been uncovered.

To test the hypothesis that newly synthesized cholesteryl esters are required for hepatic lipoprotein assembly and secretion, isolated livers of African green monkeys were perfused with medium containing an ACAT inhibitor. Three ACAT inhibitors with different structural and chemical properties were used: CI-976 (Parke-Davis), CP-113818 (Pfizer), or PD-138142-15 (Parke-Davis). Each compound produced variable effects on secretion of lipids and apolipoproteins. A significant decrease in the secretion rates of cholesteryl ester and apoB was common to all three inhibitors, indicating that fewer lipoprotein particles were secreted during ACAT inhibition. Triacylglycerol secretion was decreased in the presence of CP-113818 and PD-138142-15 but no decrease in triacylglycerol secretion was observed with CI-976. Particles secreted in the presence of CI-976 were enriched in triacylglycerol relative to apoB. Effects on secretion of other apolipoproteins (apoA-I, apoA-II, and apoE) were variable. When all data were combined, the percent inhibition of cholesteryl ester secretion and apoB secretion in the presence of ACAT inhibitors was positively correlated (r = 0.84), whereas a similar relationship was not observed between triacylglycerol and apoB. While the results demonstrate some lack of specificity for these ACAT inhibitors, the complimentary results using the three different ACAT inhibitors suggest that secretion of cholesteryl ester and apoB are coordinately regulated. The data suggest that newly synthesized cholesteryl esters may participate in and promote the assembly and secretion of hepatic apoB-containing lipoproteins. The availability of triacylglycerol during lipoprotein assembly, while also important, would appear to serve a role separate from that of cholesteryl ester.

Triglyceride, free cholesterol, and total cholesterol were quantified in lipid extracts of liver and thoracic aorta from nonhuman primates using commercially available enzymatic reagents. Lipids were solubilized in water by the addition of Triton X-100. Results of the enzymatic assays compared favorably with chemical assays of lipids separated by thin-layer chromatography. In addition to saving time, the present method has the advantage of measuring each lipid class from a single sample preparation. Furthermore, the procedure has been adapted for use with microtiter plates that conserve both sample and reagent.

Previous studies and this study of African green monkeys show a strong positive correlation between plasma low density lipoprotein (LDL) size and the extent of coronary artery atherosclerosis (CAA). Increased LDL size was principally due to the accumulation of cholesteryl oleate molecules within the particle core, suggesting that many of these cholesteryl esters were of tissue origin, i.e., from the acyl-coenzyme A:cholesterol acyltransferase (ACAT) reaction instead of the lecithin:cholesterol acyl-transferase (LCAT) reaction. The current study was conducted to test the hypothesis that ACAT in the liver is the source of the increased numbers of cholesteryl oleate molecules in plasma LDL particles that appear to increase the atherogenic potential of LDL. Monkeys were fed diets rich in fat (lard, safflower oil, or fish oil) and cholesterol for 3-6 years before liver perfusion, ACAT assay, and evaluation of CAA. Hepatic ACAT activity was positively correlated with hepatic cholesteryl ester secretion (r = 0.61, p < 0.001), plasma LDL cholesteryl ester content (r = 0.60, p < 0.0001), and the extent of CAA (r = 0.62, p < 0.0001). The number of cholesteryl oleate molecules within LDL increased proportionally with LDL size in each of the diet groups. Hepatic cholesteryl oleate concentration was correlated with the accumulation of cholesteryl oleate in liver perfusate (r = 0.72, p < 0.01) and with plasma LDL cholesterol oleate content (r = 0.73, p < 0.0001). Our interpretation is that these data, obtained in a relevant primate model of CAA, suggest that hepatic ACAT increases the atherogenicity of LDL by augmenting both the secretion by the liver and accumulation in plasma LDL of cholesteryl oleate.

The effect of copper deficiency on absolute rates of cholesterol synthesis was investigated in the rat. Male weanling rats were fed semi-purified diets containing adequate (7.13 ppm) or deficient (0.621 ppm) levels of copper for 6 weeks. Copper-adequate and -deficient animals (n = 6/group) were injected intraperitoneally with 50 mCi 3H-labelled water and killed 1 h post-injection. Copper-deficient animals had elevated heart weights and reduced body and spleen weights. Plasma cholesterol levels were significantly elevated and hematocrits were reduced. Absolute rates of carcass cholesterol synthesis per organ were 1.9-fold higher in copper-deficient rats (P less than 0.025). Previous studies have indicated that hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (E.C.1.1.1.34) activity is increased by copper deficiency; however, de novo synthesis of cholesterol from 3H-labelled water was not significantly elevated in the liver. The present data indicate that newly synthesized cholesterol exported to the plasma was increased 2.1-fold (P less than 0.01) in copper-deficient rats. Since it has been demonstrated that hepatic export of cholesterol is increased with copper deficiency and that the major tissue for export of newly synthesized cholesterol is the liver, we hypothesize that the origin of radiolabeled cholesterol in the plasma was the liver. These data support the hypothesis that elevated levels of hepatic HMG-CoA reductase seen with copper deficiency are associated with an increased rate of whole body and hepatic cholesterol synthesis.

High-density lipoprotein (HDL) catabolism induced by copper deficiency was examined in vivo in hypercholesterolemic Sprague-Dawley rats. Doubly labeled HDL was used to trace the catabolic pathways of both cholesteryl ester and protein moieties of HDL particles. The catabolic rate of removal from the plasma, as well as uptake by various tissues, was determined for each HDL component. Copper-deficient rats exhibited a 30% increase in HDL cholesterol concentration, confirming hypercholesterolemia. In addition, plasma volume was enlarged 38% in deficient animals, resulting in a significantly increased intravascular pool of all HDL components of at least 60%. These data emphasize the importance of determining plasma volume and total pool size of pertinent plasma components in this hypercholesterolemic model. The absolute catabolic rate (ACR) of HDL protein removal from the plasma was 369 +/- 22 and 278 +/- 12 micrograms/h in copper-deficient and control rats, respectively. The ACR of HDL cholesteryl ester was 647 +/- 37 micrograms/h in deficient animals and 321 +/- 13 micrograms/h in controls, suggesting that the mechanisms of selective clearance of HDL cholesteryl ester (compared with protein) were increased threefold by copper deficiency. Virtually all of the increased removal of HDL cholesteryl ester in deficient rats occurred in the liver. Since previous studies indicate that increased hepatic cholesterol excretion may not occur in copper deficiency, the present results suggest that cholesterol delivered to the liver as HDL cholesteryl ester is possibly reassembled into new HDL particles at an increased rate in copper-deficient rats.