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1.
Oxidative modification of low density lipoprotein (LDL) plays an important role in the process of atherosclerosis. The susceptibility
of LDL to oxidation and the amount of peroxidation products formed are influenced by the lipoprotein content of 18∶1 n−9,
18∶2n−6, and the 18∶2n−6/18∶1n−9 ratio, which is dependent in part on dietary fatty acids. The purpose of this study was to
determine if changing from a typical American diet to a low-fat, monousaturate-rich diet (LFMR) would result in favorable
alterations in the fatty acid composition and oxidative profile of LDL in hypercholesterolemic individuals. Free-living postmennopausal
hypercholesterolemic women who routinely consumed a diet moderately high in total fat and total saturates (34 and 11%, respectively)
followed an LFMR diet (26% fat, 6% saturated fat, and 14% monounsaturated fat) for 6 mon. Sixteen postmenopausal hypercholesterolemic
women already following standard low-fat (LF) diets acted as a control for seasonal variations in serum lipids. LDL from randomly
selected subjects (LF n=6, LFMR n=5) was evaluated. LFMR diets resulted in LDL with increased concentrations and percentages of 18∶1n−9, reduced 18∶2n−6/18∶1n−9
ratio, and lower percentages of 18∶2n−6. No significant changes in LDL fatty acids occurred in the LF group. Conjugated diene
lag time increased in both groups during copper-induced in vitro oxidation. Only the LFMR group experienced an increase in lipid peroxide lag time and a decrease in lipid peroxide formation.
The LFMR diet was well tolerated and may be of therapeutic value in the treatment of hypercholesterolemia.
A portion of this material was presented earlier at the annual meeting of the American Oil Chemists' Society and in abstract
form [O'Byrne, D.J., Shireman, R.B., Knauft, D. (1993) The effects of a low-fat/high oleic acid diet on lipoproteins in postmenopausal
hypercholesterolemic women, INFORM 4:553,#SS7]. 相似文献
2.
Ana Paula de Queiroz Mello Isis Tande da Silva Aline Silva Oliveira Valéria Sutti Nunes Dulcineia Saes Parra Abdalla Magnus Gidlund Nágila Raquel Teixeira Damasceno 《Lipids》2010,45(7):619-625
Dyslipidemias and physicochemical changes in low-density lipoprotein (LDL) are very important factors for the development
of coronary artery disease (CAD). However, pathophysiological properties of electronegative low-density lipoprotein [LDL(−)]
remain a controversial issue. Our objective was to investigate LDL(−) content in LDL and its subfractions (phenotypes A and
B) of subjects with different cardiovascular risk. Seventy-three subjects were randomized into three groups: normolipidemic
(N; n = 30) and hypercholesterolemic (HC; n = 33) subjects and patients with CAD (n = 10). After fasting, blood samples were collected and total, dense and light LDL were isolated. LDL(−) content in total
LDL and its subfractions was determined by ELISA. LDL(−) content in total LDL was lower in the N group as compared to the
HC (P < 0.001) and CAD (P = 0.006) groups. In the total sample and in those of the N, HC, and CAD groups, LDL(−) content in dense LDL was higher than
in light LDL (P = 0.001, 0.001, 0.001, and 0.033, respectively) The impact of LDL(−) on cardiovascular risk was reinforced when LDL(−) content
in LDL showed itself to have a positive association with total cholesterol (β = 0.003; P < 0.001), LDL-C (β = 0.003; p < 0.001), and non-HDL-C (β = 0.003; P < 0.001) and a negative association with HDL-C (β = −0.32; P = 0.04). Therefore, LDL(−) is an important biomarker that showed association with the lipid profile and the level of cardiovascular
risk. 相似文献
3.
Jeff S. Volek Stephen D. Phinney Cassandra E. Forsythe Erin E. Quann Richard J. Wood Michael J. Puglisi William J. Kraemer Doug M. Bibus Maria Luz Fernandez Richard D. Feinman 《Lipids》2009,44(4):297-309
We recently proposed that the biological markers improved by carbohydrate restriction were precisely those that define the
metabolic syndrome (MetS), and that the common thread was regulation of insulin as a control element. We specifically tested
the idea with a 12-week study comparing two hypocaloric diets (~1,500 kcal): a carbohydrate-restricted diet (CRD) (%carbohydrate:fat:protein = 12:59:28)
and a low-fat diet (LFD) (56:24:20) in 40 subjects with atherogenic dyslipidemia. Both interventions led to improvements in
several metabolic markers, but subjects following the CRD had consistently reduced glucose (−12%) and insulin (−50%) concentrations,
insulin sensitivity (−55%), weight loss (−10%), decreased adiposity (−14%), and more favorable triacylglycerol (TAG) (−51%),
HDL-C (13%) and total cholesterol/HDL-C ratio (−14%) responses. In addition to these markers for MetS, the CRD subjects showed
more favorable responses to alternative indicators of cardiovascular risk: postprandial lipemia (−47%), the Apo B/Apo A-1
ratio (−16%), and LDL particle distribution. Despite a threefold higher intake of dietary saturated fat during the CRD, saturated
fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker
of lipogenesis, compared to subjects consuming the LFD. Serum retinol binding protein 4 has been linked to insulin-resistant
states, and only the CRD decreased this marker (−20%). The findings provide support for unifying the disparate markers of
MetS and for the proposed intimate connection with dietary carbohydrate. The results support the use of dietary carbohydrate
restriction as an effective approach to improve features of MetS and cardiovascular risk.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
Nutritional influences on cardiovascular disease operate throughout life. Studies in both experimental animals and humans
have suggested that changes in the peri- and early post-natal nutrition can affect the development of the various components
of the metabolic syndrome in adult life. This has lead to the hypothesis that n-3 fatty acid supplementation in pregnancy
may have a beneficial effect on lipid profile in the offspring. The aim of the present study was to investigate the effect
of supplementation with n-3 fatty acids during the third trimester of pregnancy on lipids and lipoproteins in the 19-year-old
offspring. The study was based on the follow-up of a randomized controlled trial from 1990 where 533 pregnant women were randomized
to fish oil (n = 266), olive oil (n = 136) or no oil (n = 131). In 2009, the offspring were invited to a physical examination including blood sampling. A total of 243 of the offspring
participated. Lipid values did not differ between the fish oil and olive oil groups. The relative adjusted difference (95%
confidence intervals) in lipid concentrations was −3% (−11; 7) for LDL cholesterol, 3% (−3; 10) for HDL cholesterol, −1% (−6;
5) for total cholesterol,−4% (−16; 10) for TAG concentrations, 2%(−2; 7) for apolipoprotein A1, −1% (−9; 7) for apolipoprotein
B and 3% (−7; 15) in relative abundance of small dense LDL. In conclusion, there was no effect of fish oil supplementation
during the third trimester of pregnancy on offspring plasma lipids and lipoproteins in adolescence. 相似文献
5.
Kiran Musunuru 《Lipids》2010,45(10):907-914
Atherogenic dyslipidemia comprises a triad of increased blood concentrations of small, dense low-density lipoprotein (LDL)
particles, decreased high-density lipoprotein (HDL) particles, and increased triglycerides. A typical feature of obesity,
the metabolic syndrome, insulin resistance, and type 2 diabetes mellitus, atherogenic dyslipidemia has emerged as an important
risk factor for myocardial infarction and cardiovascular disease. A number of genes have now been linked to this pattern of
lipoprotein changes. Low-carbohydrate diets appear to have beneficial lipoprotein effects in individuals with atherogenic
dyslipidemia, compared to high-carbohydrate diets, whereas the content of total fat or saturated fat in the diet appears to
have little effect. Achieving a better understanding of the genetic and dietary influences underlying atherogenic dyslipidemia
may provide clues to improved interventions to reduce the risk of cardiovascular disease in high-risk individuals. 相似文献
6.
Human low density lipoproteins (LDL) were isolated and purified from individuals having widely differing serum lipid concentrations.
Very low density lipoproteins (VLDL) and high density lipoproteins (HDL) were also isolated and quantitated. HDL2 and HDL3 were separated by flotation velocity in the analytical ultracentrifuge and their relative weight percent determined. The
mean density of LDL from 41 individuals was determined by flotation velocity at two different solvent densities. The mean
density of LDL was directly proportional to the triglyceride (r=0.65) and VLDL (r=0.50) concentrations and inversely proportional
to the HDL (r=−0.55) and HDL2 (r=−0.74) concentrations (all significant at P<0.001). The mean molecular weight of LDL from 42 individuals was determined
by flotation equilibrium centrifugation. The mean molecular weight of LDL was directly proportional to the HDL (r=0.49) and
HDL2 (r=0.48) concentrations and inversely proportional to the serum triglyceride (r=−0.60) and VLDL (r=−0.48) concentrations
(all significant at P<0.005 except triglyceride—P<0.001). The molecular weight of LDL was inversely proportional to its density,
and thus inversely proportional to its protein/lipid ratio which was confirmed by composition measurements. The density and
molecular weight of LDL had no relationship to the concentration of LDL (r=0.04 and 0.03).
A preliminary report of this study was given at the American Society for Biological Chemists Meeting in St. Louis, June 1981. 相似文献
7.
TG containing stearic acid,synthesized from coconut oil,exhibit lipidemic effects in rats similar to those of cocoa butter 总被引:1,自引:0,他引:1
Lipase-catalyzed interesterification was used to prepare structured TG from coconut oil TG by partially replacing some of
the atherogenic saturated FA with stearic acid, which is known to have a neutral effect on lipid levels in the body. The level
of stearic acid was increased from 4% in the native coconut oil to 40% in the structured lipids, with most of the stearic
acid being incorporated into the sn−1 and sn−3 positions of TG. When structured lipids were fed to rats at a 10% level for a period of 60 d, a 15% decrease in total cholesterol
and a 23% decrease in LDL cholesterol levels in the serum were observed when compared to those fed coconut oil. Similarly,
the total and free cholesterol levels in the livers of the rats fed structured lipids were lowered by 31 and 36%, respectively,
when compared to those fed coconut oil. The TG levels in the serum and in the liver showed decreases of 14 and 30%, respectively,
in animals fed structured lipids. Rats fed cocoa butter and structured lipids having a similar amount of stearic acid had
similar lipid levels in the serum and liver. These studies indicated that the atherogenic potential of coconut oil lipids
can be reduced significantly by enriching them with stearic acid. This also changed the physical properties of coconut oil
closer to those of cocoa butter as determined by DSC. 相似文献
8.
This experiment was designed to evaluate the effects of dietary red wine phenolic compounds (WP) and cholesterol on lipid
oxidation and transport in rats. For 5 wk, weanling rats were fed polyunsaturated fat diets (n−6/n−3=6.4) supplemented or
not supplemented with either 3 g/kg diet of cholesterol, 5 g/kg diet of WP, or both. The concentrations of triacylglycerols
(TAG, P<0.01) and cholesterol (P<0.0002) were reduced in fasting plasma of rats fed cholesterol despite the cholesterol enrichment of very low density lipoprotein
+ low density lipoprotein (VLDL+LDL). The response was due to the much lower plasma concentration of high density lipoprotein
(HDL) (−35%, P<0.0001). In contrast, TAG and cholesteryl ester (CE) accumulated in liver (+120 and +450%, respectively, P<0.0001). However, the cholesterol content of liver microsomes was not affected. Dietary cholesterol altered the distribution
of fatty acids mainly by reducing the ratio of arachidonic acid to linoleic acid (P<0.0001) in plasma VLDL+LDL (−35%) and HDL (−42%) and in liver TAG (−42%), CE (−78%), and phospholipids (−28%). Dietary WP
had little or no effect on these variables. On the other hand, dietary cholesterol lowered the α-tocopherol concentration
in VLDL+LDL (−40%, P<0.003) and in microsomes (−60%, P<0.0001). In contrast, dietary WP increased the concentration in microsomes (+21%, P<0.0001), but had no effect on the concentration in VLDL+LDL. Cholesterol feeding decreased (P<0.006) whereas WP feeding increased (P<0.0001) the resistance of VLDL+LDL to copper-induced oxidation. The production of conjugated dienes after 25 h of oxidation
ranged between 650 (WP without cholesterol) and 2,560 (cholesterol without WP) μmol/g VLDL+LDL protein. These findings show
that dietary WP were absorbed at sufficient levels to contribute to the protection of polyunsaturated fatty acids in plasma
and membranes. They could also reduce the consumption of α-tocopherol and endogenous antioxidants. The responses suggest that,
in humans, these substances may be beneficial by reducing the deleterious effects of a dietary overload of cholesterol. 相似文献
9.
Apolipoprotein E allele 4 (apo ɛ4) and smoking each have been associated with an unfavorable lipid profile. We used data collected on 1,472 subjects in the
National Heart, Lung, and Blood Institute Family Heart Study to assess whether smoking interacts with apo ɛ4 to influence the levels of plasma lipids. We dichotomized smoking and apo ɛ4 and used analysis of covariance to estimate the means of lipids. Smokers had lower body mass index, were younger, and consumed
less fruits and vegetables. Among individuals without apo ɛ4, comparing nonsmokers with smokers, mean low density lipoprotein cholesterol (LDL) was 129.3 and 134.4 mg/dL, respectively,
for women and 126.1 and 127.6 mg/dL, respectively, for men. Among subjects with an apo ɛ4 allele, corresponding means were 132.0, and 152.9 mg/dL, respectively, for women and 131.3 and 137.3 mg/dL, respectively,
for men (P for interaction <0.001 for women and 0.11 for men). A similar interaction was observed for total cholesterol among women
(P=0.02). This study shows a statistically significant effect modification of the relation of apo ɛ4 to LDL and total cholesterol by smoking among women. Smoking may enhance genetic susceptibility to an unfavorable lipid profile
among subjects with apo ɛ4. 相似文献
10.
Effect of n−3 fatty acid-rich fish oil supplementation on the oxidation of low density lipoproteins 总被引:4,自引:0,他引:4
This study was aimed at determining the effect of fish oil supplementation on copper-catalyzed oxidation of low density lipoproteins
(LDL) from nine hypertriglyceridemic human subjects. A rapid headspace gas chromatographic method was used to measure the
volatile oxidation products from LDL. Propanal and hexanal were the major volatile products formed in the oxidation of n−3
and n−6 polyunsaturated fatty acids (PUFA), respectively. Fish oil supplementation resulted in a significant increase in propanal
formation from 3.7 to 13.4 nmol/mL LDL (P<0.01); it also resulted in small decreases in pentanal formation from 14.7 to 11.4 nmol/mL LDL and in hexanal formation from
138 to 108 nmol/mL LDL (P<0.05). The changes in peroxidation products paralleled the changes in LDL composition, which showed a significant increase
in n−3 PUFA from 3.2 to 14.6% (P<0.01) and a decrease in n−6 PUFA from 43.7 to 35.0% (P<0.05). Propanal formation was highly and significantly correlated with n−3 PUFA content (r=0.950,P<0.001). Since total volatiles remained unchanged, this indicated that the two groups of LDL samples did not differ in overall
oxidative susceptibility. Although fish oil intake did not alter the oxidative susceptibility of LDL, the chemically modified
LDL particles generated a distinct pattern of volatile oxidation products that reflected changes in their fatty acid composition. 相似文献
11.
Gazi IF Apostolou FA Liberopoulos EN Filippatos TD Tellis CC Elisaf MS Tselepis AD 《Lipids》2011,46(10):953-960
The objective of the present study was to evaluate the effects of acute infection with Leptospira interrogans on lipids, lipoproteins and associated enzymes. Fasting serum levels of total cholesterol (TC), low-density lipoprotein cholesterol
(LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), apolipoproteins (apo) A-Ι, B, E, C-II, C-III and
lipoprotein (a) [Lp(a)] were determined in patients with Leptospirosis on diagnosis and 4 months after recovery as well as
in age- and sex-matched controls. Activities of cholesteryl-ester transfer protein (CETP) and lipoprotein-associated phospholipase
A2 (Lp-PLA2) as well as paraoxonase 1 (PON1) hydrolysing activity and levels of cytokines were determined. LDL subclass analysis was
performed with Lipoprint LDL System. Eleven patients (10 men, mean age 49.5 ± 8.4 years) and 11 controls were included. TC,
HDL-C, LDL-C, apoA-I, apoB and Lp(a) levels were lower at baseline, whereas TG and apoE levels were elevated compared with
4 months later. At baseline, higher levels of cytokines and cholesterol concentration of small dense LDL particles (sdLDL-C)
were noticed, whereas LDL particle size was lower compared with follow-up. Activities of plasma Lp-PLA2 and HDL-associated Lp-PLA2 were lower at baseline compared with post treatment values, whereas PON1 activity was similar at baseline and 4 months later.
4 months after recovery, the levels of all lipid parameters evaluated did not differ compared with controls, except for HDL-C
which remained lower. PON1 activity both at baseline and 4 months later was lower in patients compared with controls. Leptospirosis
is associated with atherogenic changes of lipids, lipoproteins and associated enzymes. 相似文献
12.
Endothelial vasodilatory function is predicted by circulating apolipoprotein B and HDL in healthy humans 总被引:1,自引:0,他引:1
Endothelium-dependent vasodilation (EDV), LDL particle size, and antibodies against oxidized LDL (oxLDLab) have been shown
to be related to the development of atherosclerosis and cardiovascular disease. In this study, we investigated whether LDL
particle size, oxLDLab, apolipoproteins, and lipoproteins are related to endothelial vasodilatory function in a population
sample of 58 apparently healthy subjects aged 20 to 69 yr. EDV and endothelium-independent vasodilation (EIDV) were studied
in the forearm during local administration of methacholine chloride (2 and 4 μg/min) or sodium nitroprusside (5 and 10 μg/min).
Forearm blood flow was determined with venous occlusion plethysmography. In multiple stepwise regression analyses, neither
oxLDLab nor small LDL particles were significantly predictive of endothelial vasodilatory function. Instead, a high level
of apolipoprotein B (apoB) was an independent predictor of both attenuated EDV and EIDV (r=−0.43, P<0.01, and r=−0.34, P<0.05, respectively). HDL cholesterol, on the other hand, was the only lipid variable that was significantly related to the
EDV to EIDV ratio, an index of endothelial vasodilatory function (r=0.35, P<0.01). The inverse associations between apoB and both EDV and EIDV indicate that apoB might be an early marker of structural
vascular changes in healthy subjects, whereas HDL seems to be more specifically related to endothelial vasodilatory function. 相似文献
13.
Robert A. Gibson Mark A. Neumann Sharon L. Burnard Josephine A. Rinaldi Glen S. Patten Edward J. McMurchie 《Lipids》1992,27(3):169-176
Adult male marmoset monkeys were fed eicosapentaenoic acid (20∶5n−3) as the ethyl ester in diets containing either 32% (reference
diet, no added cholesterol) or 7% (atherogenic diet with 0.2% added cholesterol) linoleic acid (18∶2n−6) for 30 wk. No changes
were seen in the level of phosphatidylcholine (PC) or phosphatidylethanolamine (PE) but minor changes were observed in both
the sphingomyelin (SPM) and phosphatidylinositol plus phosphatidylserine (PI+PS) fractions of erythrocyte lipids. The extent
of total n−3 fatty acid incorporation into membrane lipids was higher in atherogenic diets (polyunsaturated/monounsaturated/saturated
(P/M/S) ratio 0.2∶0.6∶1.0) than reference diets (P/M/S ratio 1∶1∶1) and this was true for both PE (33.4±1.0%vs 24.3±1.1%) and PC (9.3±0.5%vs 4.9±0.3%). Although suitable controls for cholesterol effects were not included in the study, earlier results obtained with
marmosets lead us to believe such effects were probably small. Regardless of basic diet (atherogenic, reference), 20∶5n−3
was preferentially incorporated into PE (10.8±0.2%, 6.0±0.02%) while smaller amounts were incorporated into PC (6.9±0.4%,
3.2±0.2%). The major n−3 polyunsaturated fatty acid found in PE in response to dietary 20∶5n−3 was the elongation metabolite
22∶5n−3 in both the atherogenic (17.7±0.7%) and reference (14.3±1.0%) dietary groups; 22∶6n−3 levels were less affected by
diet (4.7±0.3% and 3.9±0.2%, respectively). The results can be interpreted to indicate an inverse relationship between the
amount of dietary 18∶2n−6 and incorporation of 20∶5n−3 into erythrocyte membrane phospholipids regardless of whether the major
dietary n−3 fatty acid was α-linolenate (18∶3n−3) or 20∶5n−3. This interpretation is supported by theoretical calculations. 相似文献
14.
Coni E Di Benedetto R Di Pasquale M Masella R Modesti D Mattei R Carlini EA 《Lipids》2000,35(1):45-54
On the basis of the results obtained with pilot studies conducted in vitro on human low density lipoprotein (LDL) and on cell cultures (Caco-2), which had indicated the ability of certain molecules
present in olive oil to inhibit prooxidative processes, an in vivo study was made of laboratory rabbits fed special diets. Three different diets were prepared: a standard diet for rabbits
(diet A), a standard diet for rabbits modified by the addition of 10% (w/w) extra virgin olive oil (diet B), a modified standard
diet for rabbits (diet C) differing from diet B only in the addition of 7 mg kg−1 of oleuropein. A series of biochemical parameters was therefore identified, both in the rabbit plasma and the related isolated
LDL, before and after Cu-induced oxidation. The following, in particular, were selected: (i) biophenols, vitamins E and C,
uric acid, and total, free, and ester cholesterol in the plasma; (ii) proteins, triglycerides, phospholipids, and total, free,
and ester cholesterol in the native LDL (for the latter, the dimensions were also measured); (iii) lipid hydroperoxides, aldehydes,
conjugated dienes, and relative electrophoretic mobility (REM) in the oxidized LDL (ox-LDL). In an attempt to summarize the
results obtained, it can be said that this investigation has not only verified the antioxidant efficacy of extra virgin olive
oil biophenols and, in particular, of oleuropein, but has also revealed a series of thus far unknown effects of the latter
on the plasmatic lipid situation. In fact, the addition of oleuropein in diet C increased the ability of LDL to resist oxidation
(less conjugated diene formation) and, at the same time, reduced the plasmatic levels of total, free, and ester cholesterol
(−15, −12, and −17%, respectively), giving rise to a redistribution of the lipidic components of LDL (greater phospholipid
and cholesterol amounts) with an indirect effect on their dimesions (bigger by about 12%). 相似文献
15.
Low density lipoprotein (LDL) plasma concentration is increased in the elderly. In this group, the incidence of coronary artery
disease (CAD) is greater and LDL remains an important risk factor for CAD development. In this study, the plasma kinetics
of a cholesterol-rich emulsion that binds to LDL receptors was studied in 10-subject groups of the elderly (70±4 yr), middle-aged
(42±5 yr) and young (23±2 yr). All were normolipidemic, nonobese, nondiabetic subjects who did not have CAD. The emulsion
was labeled with 14C-cholesteryl oleate and injected intravenously into the subjects. Blood samples were drawn at regular intervals over 24 h
to determine the plasma decay curve of the emulsion radioactive label and to estimate its plasma fractional clearance rate
(FCR, in h−1). FCR of the emulsion label was smaller in elderly compared to young subjects (0.032±0.035 and 0.071±0.049 h−1, respectively; mean±SD, P<0.05). FCR of the middle-aged subjects (0.050±0.071 h−1) was intermediate between the values of the elderly and young subjects, although not statistically different from them. A
negative correlation was found between the emulsion FCR and subjects’ age (r=−0.47, P=0.008). We conclude that aging is accompanied by progressively diminished clearance of the emulsion cholesterol esters and,
by analogy, of the native LDL. 相似文献
16.
Soy isoflavones may impede atherogenic processes associated with cardiovascular disease. Research suggests that the postprandial
generation of TG-rich remnants contributes to the development of atherosclerosis. The purpose of the current study was to
determine if 39 g soy (85 mg aglycone isoflavones, treatment) compared with 40 g milk protein (0 mg aglycone isoflavones,
control) in combination with a high-fat meal can modify postprandial, atherogenic-associated events and biomarkers for oxidative
stress, inflammation, and thrombosis. Fifteen healthy men (20–47 yr) participated in a double-blind cross-over meal-challenge
study occurring on two nonconsecutive days. The study meals consisted of two high-fat apple muffins consumed with either a
soy or milk shake (229 mL, 41% fat, 41% carbohydrate, and 18% protein). Blood samples were obtained at base-line (fasted)
and hours two, four, and six postprandial. Plasma TG significantly increased in both treatment and control meal challenges
compared with baseline. There were no significant differences (P>0.05) between treatment (soy) and control (milk) for ex vivo copper-induced LDL oxidation, serum C-reactive protein, serum interleukin-6 (IL-6), serum fibrinogen, or plasma lipids (total
cholesterol, HDL, LDL, TG). IL-6-concentrations significantly decreased as a function of time during either meal challenge
(P=0.005). These data suggest that consumption of soy or milk protein in conjunction with a high-fat meal does not acutely modify
postprandial oxidative stress, inflammation, or plasma lipid concentrations in young, healthy men. 相似文献
17.
(−)-Hydroxycitrate and (+)-allo-hydroxycitrate were investigated for their effects on lipid synthesis in vivo under conditions of either high carbohydrate
feeding or 24 hr fasting. Changes in rates of lipid synthesis resulting from the oral administration of these compounds were
monitored with the use of radiolabeled H2O, alanine, and acetate. In the fed rat, (−)-hydroxycitrate significantly reduced the incorporation of H2O and alanine into fatty acids and cholesterol. An increased incorporation of labeled H2O into fatty acids but no change in cholesterol synthesis in the fasted rat suggested that (−)-hydroxycitrate may be an activator
of acetyl CoA carboxylase. With (−)-hydroxycitrate administration, acetate incorporation into fatty acids and cholesterol
was subject to pool dilution effects under fed or fasted states. (+)-allo-Hydroxycitrate was ineffective in modulating the rates of fatty acid synthesis under either nutritional condition. Both (−)-hydroxycitrate
and (+)-allo-hydroxycitrate were shown to be in vitro activators of acetyl CoA carboxylase, the former being a much stronger activator
than the latter. Thus, stereospecificity of the hydroxycitrate isomers was demonstrated in both the inhibition of lipid synthesis
(previously shown to occur at adenosine triphosphate citrate lyase) and the stimulation of fatty acid synthesis (possibly
occurring at acetyl CoA carboxylase). 相似文献
18.
Fatty acid analysis of blood serum, seminal plasma, and spermatozoa of normozoospermic vs. Asthernozoospermic males 总被引:2,自引:0,他引:2
Docosahexaenoic acid (DHA; 22∶6n−3) is found in extremely high levels in human ejaculate with the majority occurring in the
spermatozoa. However, the relative concentration of DHA and other fatty acids, in blood serum, seminal plasma, and spermatozoa
of asthenozoospermic vs. normozoospermic individuals is not known. We analyzed the phospholipid fatty acid composition of
blood serum, seminal plasma, and spermatozoa of normozoospermic men and asthenozoospermic men in order to determine if DHA
levels, as well as the levels of other fatty acids, differed. The serum phospholipid DHA levels were similar in the two groups,
suggesting similar intakes of dietary DHA. On the other hand, seminal plasma levels of DHA (3.0 vs. 3.7%) and total polyunsaturated
fatty acids (PUFA) (11.8 vs. 13.5%) were significantly lower in asthenozoospermic vs. normozoospermic men, respectively, while
18∶1 (19.0 vs. 16.8%) and monounsaturated fatty acids (MUFA) (24.2 vs. 21.7%) were significantly higher in the asthenozoospermic
vs. the normozoospermic men. Spermatozoa from asthenozoospermic men had higher levels of 18∶1, 20∶0, 22∶0, 22∶1, and 24∶0
than sperm from normozoospermic men, and lower levels of 18∶0 and DHA (8.2 vs. 13.8%). Furthermore, total MUFA (19.3 vs. 16.5%)
was higher and total PUFA (19.0 vs. 24.0%), n−3 fatty acids (9.3 vs. 14.6%), and the ratio of n−3 to n−6 fatty acids (1.0
vs. 1.6) were lower in the asthenozoospermic men. Therefore, in asthenozoospermic individuals, lower levels of DHA in the
seminal plasma, but not in the blood serum, mimic the decreased concentrations of DHA in the spermatozoa. This suggests that
the lower concentrations of spermatozoon DHA in these individuals are due not to dietary differences but to some type of metabolic
difference in the asthenozoopermic men. 相似文献
19.
This study was conducted to develop a quantitative FTIR spectroscopy method to measure LDL lipid oxidation products and determine
the effect of oxidation on LDL lipid and protein. In vitro LDL oxidation at 37°C for 1 h produced a range of conjugated diene (CD) (0.14–0.26 mM/mg protein) and carbonyl contents (0.9–3.8
μg/g protein) that were used to produce calibration sets. Spectra were collected from the calibration set and partial least
squares regression was used to develop calibration models from spectral regions 4000-650, 3750-3000, 1720-1500, and 1180-935
cm−1 to predict CD and carbonyl contents. The optimal models were selected based on their standard error of prediction (SEP),
and the selected models were performance-tested with an additional set of LDL spectra. The best models for CD prediction were
derived from spectral regions 4000-650 and 1180-935 cm−1 with the lowest SEP of 0.013 and 0.013 mM/mg protein, respectively. The peaks at 1745 (cholesterol and TAG ester C=O stretch),
1710 (carbonyl C-O stretch), and 1621 cm−1 (peptide C=O stretch) positively correlated with LDL oxidation. FTIR and chemometrics revealed protein conformation changes
during LDL oxidation and provided a simple technique that has potential for rapidly observing structural changes in human
LDL during oxidation and for measuring primary and secondary oxidation products. 相似文献
20.
In most studies reporting the effects of high-fat (HF) and low-fat (LF) diets on human plasma fatty acids (FA) and lipoprotein
levels, the design involved adding to the diet an oil that had an FA composition (FAC) very different from the FAC of the
control diet. Thus, it is difficult to determine if simply reducing the fat content of the diet without changing the dietary
FAC changes the tissue FAC or alters plasma lipid levels. In this study, we fed diets that contained either 22 or 39% of calories
from fat, but had no differences in their FAC, for 50 d to a group (n=11) of healthy men (20–35 y). Thus, the polyunsaturated/saturated
ratios (1.0) of the diets were identical as were the n−3/n−6 ratio and the monounsaturated-to-total fat ratios. The diets
contained (wt% of total fat) approximately 28% saturated FA, 33% monounsaturatedcis-FA, 6% monounsaturatedtrans-FA, 22% n−6 polyunsaturated FA, and 7% n−3 polyunsaturated FA, and 4% other minor FA. The diets consisted of natural foods
and were formulated to contain 16 en% protein, either 45 or 62 en% carbohydrate (CHO) and at least the recommended dailyallowance
for all micronutrients. Both diets contained 360 mg of cholesterol per day. All subjects were given the HF diet for 20 d,
and then six were placed on the LF and the other five remained on the HF diet for 50 d. The two groups were crossedover for
the remaining 50 d of the study. The subjects' baseline total cholesterol level was 173 mg/dl, after 50 d on the HF diet it
was 177 mg/dl and after 50 d on the LF diet, 173 mg/dl. The differences were not significant, and there were no significant
changes in either the LDL or HDL cholesterol levels with either diet. Triglyceride levels, and consequently very low density
lipoprotein levels, rose significantly on the LF, higher CHO diet compared to the levels found in the subjects on the HF diet
(91.5 and 66.4 mg/dl respectively,P<0.002). The linoleic acid content of the plasma, platelets, and red blood cells was significantly (P<0.05) reduced in the LF diet compared to HF diet, without any obvious physiological effects. Hence, many earlier observations
indicating reductions in plasma lipid levels when people are on LF diets may be due to changes in the FAC of the diet, not
the reduction in fat calories. 相似文献