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Biomedical subjects

L L Rudel

Publications and source records attributed to L L Rudel.

At least 55 records · Page 3Linked to original sources
PubMed1995

Compared with dietary monounsaturated and saturated fat, polyunsaturated fat protects African green monkeys from coronary artery atherosclerosis.

Atherogenic diets enriched in saturated, n-6 polyunsaturated, and monounsaturated fatty acids were fed to African green monkeys for 5 years to define effects on plasma lipoproteins and coronary artery atherosclerosis. The monkeys fed polyunsaturated and monounsaturated fat had similar plasma concentrations of LDL cholesterol, and these values were significantly lower than for LDL in the animals fed saturated fat. Plasma HDL cholesterol concentrations were comparable in animals fed saturated and monounsaturated fat and were significantly higher than in animals fed polyunsaturated fat. Thus, the monounsaturated fat group had the lowest LDL/HDL ratio. LDL particle size was largest in the saturated and monounsaturated fat groups, significantly larger than in the polyunsaturated fat group. LDL particle enrichment with cholesteryl oleate was the greatest in the animals fed monounsaturated fat, next greatest in the saturated fat-fed animals, and was least in the polyunsaturated fat-fed animals. Coronary artery atherosclerosis as measured by intimal area was less in the polyunsaturated fat compared with the saturated fat groups, was less in the animals fed polyunsaturated fat compared with the monounsaturated fat-fed animals, but did not differ between the monounsaturated and saturated fat groups. Cholesteryl ester, particularly cholesteryl oleate, accumulation in the coronary arteries was also similar between groups fed monounsaturated and saturated fat but was minimal in the animals fed polyunsaturated fat. In sum, the monkeys fed monounsaturated fat developed equivalent amounts of coronary artery atherosclerosis as those fed saturated fat, but monkeys fed polyunsaturated fat developed less. The beneficial effects of the lower LDL and higher HDL in the animals fed monounsaturated fat apparently were offset by the atherogenic shifts in LDL particle composition. Dietary polyunsaturated fat appears to result in the least amount of coronary artery atherosclerosis because it prevents cholesteryl oleate accumulation in LDL and the coronary arteries in these primates.

Animals↗
PubMed1995

Accelerated cholesteryl ester transfer and altered lipoprotein composition in diabetic cynomolgus monkeys.

To determine whether nonhuman primates demonstrate the same alterations in transport of cholesteryl ester (CE) in plasma observed in diabetic humans, cholesteryl ester transfer (CET) was measured in cynomolgus monkeys with chronic spontaneous diabetes mellitus (glycated hemoglobin: diabetics 10.7 +/- 4.1%; controls 3.8 +/- 0.8%, P < 0.005). Among the plasma lipids, only triglycerides were significantly increased in diabetic monkeys (diabetics 303 +/- 294 mg/dl; controls 85 +/- 34 mg/dl; P < 0.05); total plasma, LDL, HDL2, and HDL3 cholesterol concentrations did not differ significantly from those of control animals. Similar to human beings with insulin-dependent and non-insulin-dependent diabetes mellitus, CET estimated both as the mass of cholesteryl ester transferred from HDL to the apoB-containing lipoproteins (VLDL + LDL) and as the loss of radiolabeled cholesteryl ester from HDL was significantly greater (P < 0.001) in diabetic compared to control monkeys. Glycated hemoglobin levels in the combined control and diabetic groups correlated directly with both the mass of cholesteryl ester transferred at 2 h (r = 0.75; P < 0.001) and the isotopic transfer (k) (r = 0.64; P < 0.005). The mass of cholesteryl ester transfer protein (CETP) tended to be higher in the diabetic animals (diabetic 4.06 +/- 0.73 microgram/ml versus control 3.05 +/- 0.93; P < 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

ACAT inhibitors CL 283,546 and CL 283,796 reduce LDL cholesterol without affecting cholesterol absorption in African green monkeys.

Previous studies with a number of selective acylcoenzyme A:cholesterol acyltransferase (ACAT) inhibitors in several animal models have demonstrated significant reductions in plasma cholesterol and, in some studies, triglyceride levels. This study was conducted to examine the effects of two ACAT inhibitors, CL 283,546 and CL 283,796, in cholesterol-high fat diet fed African green monkeys, a relevant primate model of hyperlipidemia and coronary artery atherosclerosis. Treatment with CL 283,546 or CL 283,796 resulted in significant reductions (ca. 25-30%) in total plasma cholesterol at both 10 and 30 mg/kg per day doses. This reduction in plasma cholesterol was due almost entirely to reduction in low density lipoprotein (LDL) cholesterol (ca. 45%) without significantly affecting high density lipoprotein (HDL) cholesterol, very low density lipoprotein + intermediate density lipoprotein (VLDL + IDL) cholesterol, or triglyceride concentrations. There were no significant effects on plasma concentrations of apolipoproteins A-I, E, or B and, thus, the reduction seen in LDL cholesterol appears to be due to a diminished cholesterol content of LDL particles. Our studies revealed that treatment with these compounds did not reduce cholesterol absorption, which was somewhat surprising as ACAT inhibitors are generally thought to exert their hypolipidemic effects, at least in part, by inhibition of intestinal cholesterol absorption. Our data are consistent with a principal activity of these drugs on the liver to reduce cholesteryl ester secretion in VLDL, leading to a diminished LDL-cholesterol content, and, presumably, enhanced biliary cholesterol-bile acid excretion.

Animals↗
PubMed1995

ACAT inhibitors decrease secretion of cholesteryl esters and apolipoprotein B by perfused livers of African green monkeys.

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.

Anilides↗
PubMed1995

Dietary fatty acid modification of HDL phospholipid molecular species alters lecithin: cholesterol acyltransferase reactivity in cynomolgus monkeys.

In the following report, cynomolgous monkeys, fed atherogenic diets containing either saturated, monounsaturated, polyunsaturated (n-6 Poly) or fish oil (n-3 Poly) fat as 35% of total calories, provide a model for the study of dietary fat effects on plasma lipoproteins and atherosclerosis. We have previously described the ability of polyunsaturated fat diets to lower plasma described the ability of polyunsaturated fat diets to lower plasma high density lipoprotein (HDL) cholesterol levels and alter HDL subpopulation distribution in the primate model. These experiments investigate possible mechanisms responsible for such modifications. Animals fed polyunsaturated fat had significantly lower plasma concentrations of HDL cholesterol, total plasma cholesterol, and apolipoprotein A-I. Such changes were reflected in the distribution of protein among HDL subfractions, with the most remarkable modification in subclass distribution being the preponderance of small HDL particles in the n-3 Poly-fed animals. Striking alterations were also observed in the distribution of phosphatidylcholine (PC) molecular species (diet effect P < 0.0001 for all major molecular species). Phosphatidylcholine isolated from lipoproteins were used to make recombinant HDL (rHDL) particles. The reaction rate of purified lecithin:cholesterol acyltransferase (LCAT) with particles made from n-3 Poly-derived PC was 50% of that determined using rHDL formed with PC from other dietary groups (P < 0.0001). When the distribution of LCAT-derived rHDL cholesteryl esters was analyzed, LCAT demonstrated little selectivity for certain PC molecular species except in n-3 Poly-derived rHDL where 18:2-containing PC was selectively utilized. These data demonstrate that differences in dietary fat intake can significantly alter HDL PC concentration and molecular species distribution. We suggest that diet-induced alterations in HDL PC molecular species modify the type of cholesteryl esters produced during the LCAT reaction thereby affecting the plasma cholesteryl ester pool. We also propose that dietary n-3 Poly affects cholesteryl ester metabolism in part via LCAT by lowering PC (LCAT substrate) availability, altering the rate of the LCAT reaction, and decreasing HDL cholesterol concentrations; however, n-6 Poly dietary fat effects on HDL concentration appear to be through some mechanism other than LCAT.

Animals↗
PubMed1994

Fatty acid composition of low-density lipoprotein influences its susceptibility to autoxidation.

Low-density lipoprotein (LDL) oxidation was studied using copper or the water-soluble initiator azobis(2-amidinopropane) dihydrochloride (ABAP) to catalyze the reaction. These studies were carried out with purified, native LDLs that had a well-defined composition and which contained different concentrations of polyunsaturated fatty acids (PUFA) and alpha-tocopherol. The LDL was obtained from nonhuman primates fed diets enriched in cholesterol and one of four types of fatty acids: saturated (Sat), monounsaturated (Mono), omega-6 (omega-6FA), or omega-3 (omega-3FA) fatty acids. The PUFA concentration of the LDLs depended upon the diet and had the following order: omega-6FA > Sat approximately Mono approximately omega-3FA. Linoleic acid was the predominant PUFA in all of the LDLs. The rates of oxidation were linearly dependent upon the concentration of PUFA. When ABAP was used to initiate oxidation the lag time was linearly related to the amount of alpha-tocopherol. However, with copper catalysis no linear correlation was evident. If the different enrichments were analyzed independently, it was found that copper-catalyzed oxidation of LDLs enriched with omega-6 and omega-3 fatty acids showed a linear correlation between the lag time and the amount of alpha-tocopherol but that LDLs enriched with Sat or Mono fatty acids did not show a correlation. These results demonstrate that the rate of oxidation is dependent upon PUFA concentration and that the ability of alpha-tocopherol to inhibit oxidation depends upon the lipid environment and the mode of initiation.

Amidines↗
PubMed1994

Dietary polyunsaturated fat decreases interaction between low density lipoproteins and arterial proteoglycans.

Polyunsaturated dietary fat (n-3 and n-6) results in less atherosclerosis in monkeys compared to lard (Parks, J.S., Kaduck-Sawyer, J., Bullock, B.C., and Rudel, L.L., Arteriosclerosis 10, 1102-1112; Rudel, L.L., Parks, J.S., Johnson, F.L., and Babiak, J., J. Lipid Res. 27, 465-474, 1986). We hypothesized that this was due, in part, to a decreased reactivity of low density lipoproteins (LDL) with arterial proteoglycans (PG). To test this hypothesis, cynomolgus monkeys were fed diets containing lard, safflower oil (n-6 polyunsaturated; Poly), menhanden fish oil (FO), or oleic acid-rich safflower oil (oleinate; Mono) for 14 mon, and plasma LDL were isolated and characterized. Several properties of LDL thought to be important in the interaction of LDL with arterial PG were measured including LDL particle size, chemical composition, sialic acid content, density distribution, apolipoprotein E (apoE) content and cholesteryl ester transition temperature. Plasma LDL cholesterol concentrations (mg/dL) after 14 mon of diet consumption averaged (mean +/- SEM): FO (366 +/- 45), Lard (352 +/- 27), Poly (279 +/- 24), and Mono (230 +/- 43). The composition of LDL was similar among diet groups except that FO LDL were relatively depleted of cholesteryl ester and enriched in protein and were smaller in size. LDL sialic acid content was similar among diet groups (4.5-5.0 micrograms/mg LDL protein). The LDL apoE/B molar ratio, a measure of the apoE content per LDL particle averaged: Mono (3.0 +/- 1.0), Poly (2.0 +/- 0.1), Lard (1.8 +/- 0.5), and FO (1.0 +/- 0.2).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Dietary polyunsaturated fat decreases coronary artery atherosclerosis in a pediatric-aged population of African green monkeys.

The hypothesis tested was that juvenile African green monkeys consuming diets enriched with n-6 polyunsaturated fat from birth until young adulthood would have significantly less coronary artery atherosclerosis than comparable animals consuming diets enriched with saturated fat. African green monkeys (Cercopithecus aethiops, n = 108) of both sexes were fed atherogenic diets (0.8 mg cholesterol/kcal) throughout their lives so that death at 16, 32, or 60 months of age permitted quantification of atherosclerosis. In the coronary arteries, the average intimal area increased significantly with age (P = .02), showing increases of 28-fold and sevenfold between 32 and 60 months in the saturated fat- and polyunsaturated fat-fed groups, respectively. Young adult male animals at 60 months of age were found to have significantly (P = .03) more coronary artery atherosclerosis than female animals. Animals fed polyunsaturated fat had significantly (P < or = .01) less coronary artery atherosclerosis. By 60 months of age in the animals consuming polyunsaturated fat, the average coronary artery intimal area was one fourth and the average size of the largest coronary intimal lesion was one fifth that in monkeys fed saturated fat. Low-density lipoprotein (LDL) cholesterol and LDL particle size were each found to be positively correlated with coronary artery atherosclerosis end points in both diet groups. In addition to the coronary arteries, atherosclerosis in the abdominal and thoracic aorta and carotid arteries was also evaluated; the coronary arteries were the only arterial system with significantly less atherosclerosis in the polyunsaturated fat group as measured by intimal area. However, evaluation of histological sections of abdominal aorta showed relatively more sterol clefts in the saturated fat-fed group, and more free cholesterol was measured, suggesting that lesions were more complicated in this group. These results show that dietary intervention early in life with n-6 polyunsaturated fat can be effective in decreasing the development of atherosclerosis, particularly in the coronary arteries of primates. This outcome supports the concept that dietary intervention beginning early in childhood can have beneficial effects on the coronary heart disease of later life.

Aging↗
PubMed1993

Enzymatic determination of triglyceride, free cholesterol, and total cholesterol in tissue lipid extracts.

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.

Animals↗
PubMed1993

Childhood consumption of dietary polyunsaturated fat lowers risk for coronary artery atherosclerosis in African green monkeys.

This study was designed to test the hypothesis that consumption of diets enriched in polyunsaturated fatty acids beginning at birth and continuing into young adulthood would lower the risk for atherosclerotic coronary heart disease early in life through their effects on plasma lipid and apolipoprotein concentrations while supporting good health and normal development. Accordingly, African green monkeys (n = 140) were raised on atherogenic diets (0.8 mg cholesterol per kcal) enriched with either saturated or n-6 polyunsaturated fatty acids. Breast milk from mothers fed the polyunsaturated fat diet became enriched in polyunsaturated fatty acids relative to the saturated group; thus, the period of nursing also reflected the dietary fatty acid shift. Age, gender, and dietary fat type independently affected plasma lipid and apolipoprotein concentrations. Age effects were similar for all lipid and lipoprotein variables; the concentrations were low immediately after birth, increased dramatically during the first 4-6 months of life, and then attained levels similar to those of adult animals by 2 years of age. Significant differences by gender were found such that females maintained lower total plasma cholesterol concentrations and higher high density lipoprotein (HDL) cholesterol and apolipoprotein (apo) A-I concentrations. Dietary fat effects were age dependent. Before weaning at 5 months of age, total plasma cholesterol and apoB concentrations were lower in animals consuming polyunsaturated fat, and this pattern was maintained into young adulthood. Lower concentrations of plasma triglycerides, HDL cholesterol, and apoA-I for polyunsaturated fat-fed animals were found only in the postweaning period (6-60 months of age). Since this pattern of response to dietary polyunsaturated fat in the juvenile animals was similar to that for adult animals fed these same diets in which there was less atherosclerosis and because subsequent studies have documented less coronary artery atherosclerosis in the polyunsaturated fat-fed juveniles, we conclude that early dietary intervention was beneficial in this group for lowering the risk of coronary artery atherosclerosis. The results in this primate model support the concept that intervention to modify coronary heart disease risk that is initiated early in childhood will have beneficial effects.

Aging↗
PubMed1993

Interrelationships of alpha-tocopherol with plasma lipoproteins in African green monkeys: effects of dietary fats.

The distributions of plasma lipoprotein alpha-tocopherol and lipids were studied in African green monkeys consuming diets enriched in saturated, monounsaturated, or polyunsaturated fatty acids. Plasma total alpha-tocopherol concentrations were not different among the animals fed the three diets, whereas plasma total cholesterol concentrations were significantly different among the diet groups. The alpha-tocopherol: total lipid molar ratio in plasma high density lipoproteins (HDL) was significantly higher compared to low density lipoproteins (LDL) and very low plus intermediate-sized low density lipoprotein (VLDL + ILDL) of each diet group, suggesting that HDL may exhibit a greater affinity for alpha-tocopherol. The presence of a positive correlation between HDL alpha-tocopherol and plasma apoA-I concentration and the absence of a correlation between HDL alpha-tocopherol and total lipid in HDL suggested that alpha-tocopherol associates with the protein moiety of HDL on the surface of the particle. A direct relationship between the plasma apoA-I: apoB molar ratio and the percentage of alpha-tocopherol found in the HDL fraction indicated that a greater proportion of alpha-tocopherol associates with HDL as the number of HDL particles in plasma increases relative to LDL particles. LDL from monkeys fed diets high in saturated fat contained 40% and 33% fewer alpha-tocopherol molecules per particle than LDL from monkeys fed polyunsaturated and monounsaturated fats, respectively. The phase transition temperature of LDL cholesteryl esters, indicative of the physical state of the lipids in the particle core, was well above body temperature in LDL from saturated fat-fed monkeys and was significantly higher compared to the other diet groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Age- and dietary fat-related effects on biliary lipids and cholesterol gallstone formation in African green monkeys.

The effects of age and dietary fat on bile cholesterol saturation index (CSI) and cholesterol gallstone formation were studied in three age groups of male African green monkeys. Animals were fed semipurified diets containing cholesterol (0.34 g/100 g diet) and 42% of energy as saturated or polyunsaturated fat. Animals were killed at 16 (pre-pubertal), 32 (peri-pubertal) or 60 (young adult) mo of age; the presence of gallstones was determined and gallbladder bile was analyzed for CSI and bile acid composition. Cholesterol gallstones were present in 9% of 60-mo-old animals, compared with a 42% incidence in adult animals fed these same diets for 5 y. Gallbladder bile from the 32-mo-old group contained significantly more cholesterol and had a higher CSI as compared with the other age groups. Dietary fat had no effect on biliary lipid composition. We conclude that the increase in CSI around the time of puberty in male monkeys is not clinically significant in terms of gallstone formation, and that polyunsaturated fat feeding is not associated with adverse effects. Because the incidence of gallstone formation in these young adults was lower than that seen in older adults, a minimal amount of time consuming a lithogenic diet as an adult seems to be required for stone genesis.

Aging↗
PubMed1992

Role of apolipoprotein E on cholesteryl ester-enriched low density lipoprotein particles in coronary artery atherosclerosis of hypercholesterolemic nonhuman primates.

Significant differences among individuals occur in the lipoprotein response to atherogenic diets in cynomolgus and African green monkeys. The range of concentrations of total plasma cholesterol (TPC) was 100-600 mg/dl and of apolipoprotein (apo) E (quantified by enzyme-linked immunosorbent assay) was 3-20 mg/dl in the animal groups of this study. The correlation between the concentrations of TPC and of apo E was r = 0.89 in these animals. To determine which lipoprotein classes contained the majority of apo E, agarose gel-filtration chromatography was used to subfractionate whole plasma. In hypercholesterolemic monkeys, the majority of the apo E and apo B-100 coeluted within the region of low density lipoprotein (LDL). In normocholesterolemic monkeys, the majority of apo E coeluted with apo A-I and high density lipoproteins. A strong positive correlation was seen between the concentrations of plasma apo E and LDL cholesterol (r = 0.9), but there was no significant correlation between high density lipoprotein apo E and either TPC or plasma apo E concentrations. A positive correlation of r = 0.8 was found between the LDL apo E to apo B-100 molar ratio and the average LDL particle size, suggesting an increase in the number of apo E molecules on the larger LDL particles. Within individual animals, LDL were heterogeneous and the LDL subfractions of lower density (1.02 less than d less than 1.03 g/ml) had the highest proportion of apo E, although apo E was present on LDL of all densities. A strong positive correlation between plasma apo E concentration and coronary artery atherosclerosis was identified, and in stepwise regression analysis, plasma apo B concentration and the apo E to apo B molar ratio of LDL together accounted for more than 90% of the variation in the atherosclerosis end point of coronary artery intimal area. These data strongly suggest that the enrichment of LDL with cholesteryl esters and apo E, which occurs in hypercholesterolemic primates, is an atherogenic feature of the plasma lipoproteins.

Animals↗
PubMed1992

Hepatic ACAT activity in African green monkeys is highly correlated to plasma LDL cholesteryl ester enrichment and coronary artery atherosclerosis.

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.

Animals↗
PubMed1991

Dietary fish oil effects on biliary lipid secretion and cholesterol gallstone formation in the African green monkey.

We studied two groups of adult male African green monkeys to assess the effects of dietary fish oil on biliary lipid secretion and cholesterol gallstone formation. One group was fed 0.8 mg cholesterol/kcal and 42% of calories as fat with half of the fat calories derived from lard; the other group was fed a similar diet except for the isocaloric substitution of menhaden oil for lard. After 2 1/2 to 3 yr, necropsies were performed and the presence of gallstones was determined. Gallbladder bile specimens were analyzed for cholesterol saturation index, as well as for bile acid species and biliary phospholipid fatty acid composition. Our results showed that 67% of animals fed the lard diet had cholesterol gallstones compared with only 22% of animals in the group fed the fish oil diet (p = 0.08). The cholesterol saturation index of gallbladder bile also tended to be higher in the lard-fed group (1.15 +/- 0.11) compared with the fish oil-fed group (0.86 +/- 0.09, p = 0.06). No differences between the two dietary groups were noted in the percentages of the various types of bile acids. However, a greater percentage of omega-3 fatty acids and a lesser percentage of 18:1, 18:2 and 20:4 fatty acids were found in the biliary phospholipids from the fish oil-fed group compared with the lard-fed group. Biliary lipid secretion rates were then measured during isolated recirculating liver perfusion performed with a constant sodium taurocholate infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Plasma HDL cholesterol concentrations are correlated to bile cholesterol saturation index in the African green monkey.

In an attempt to determine if plasma lipoprotein concentrations correlate with the bile cholesterol saturation index in the African green monkey, we have studied a group of adult male animals available from a long-term study investigating the effects of dietary fat and cholesterol on cholesterol metabolism and atherosclerosis. The animals were fed diets containing 0.8 mg cholesterol/kcal or 0.03 mg cholesterol/kcal for five years. Within each dietary cholesterol group, animals received 42% of dietary calories as fat, enriched with either saturated or polyunsaturated fat. Using stepwise multiple linear regression, high density lipoprotein (HDL) cholesterol concentration was found to be the best plasma lipid predictor of the bile cholesterol saturation index. When the cholesterol saturation index of a fasting gallbladder bile specimen was compared to the plasma HDL cholesterol level for individual animals, a significant positive correlation was noted for animals fed polyunsaturated fat, (r = 0.68) and for animals fed saturated fat (r = 0.72). For any value of HDL cholesterol, however, the cholesterol saturation index was higher in animals fed polyunsaturated fat compared to saturated fat. Since plasma HDL cholesterol levels were positively correlated with the bile cholesterol saturation index in adult male African green monkeys, we conclude that a metabolic link exists between plasma HDL cholesterol concentrations and bile cholesterol saturation, perhaps due to enhanced delivery of cholesterol to the liver by HDL.

Animals↗