(Circulation. 1999;99:1355-1362.)
© 1999 American Heart Association, Inc.
Basic Science Reports |
Reduction of Serum Cholesterol and Hypercholesterolemic Atherosclerosis in Rabbits by Secoisolariciresinol Diglucoside Isolated From Flaxseed
From the Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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Abstract |
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Background—Secoisolariciresinol diglucoside (SDG) is a plant lignan isolated from flaxseed. Lignans are platelet-activating factor–receptor antagonists that would inhibit the production of oxygen radicals by polymorphonuclear leukocytes. SDG is an antioxidant. Antioxidants studied thus far are known to reduce hypercholesterolemic atherosclerosis. The objective of this study was to determine the effect of SDG on various blood lipid and aortic tissue oxidative stress parameters and on the development of atherosclerosis in rabbits fed a high-cholesterol diet.
Methods and Results—Rabbits were assigned to 4 groups: group 1,
control; group 2, SDG control (15 mg · kg body
wt-1 · d-1 PO); group 3, 1%
cholesterol diet; and group 4, same as group 3 but with
added SDG (15 mg · kg body wt-1 ·
d-1 PO). Blood samples were collected before (time 0) and
after 4 and 8 weeks of experimental diets for measurement of serum
triglycerides, total cholesterol (TC), and LDL,
HDL, and VLDL cholesterol (LDL-C, HDL-C, and VLDL-C). The
aorta was removed at the end of the protocol for assessment of
atherosclerotic plaques; malondialdehyde, an aortic tissue lipid
peroxidation product; and aortic tissue chemiluminescence, a marker
for antioxidant reserve. Serum TC, LDL-C, and the ratios LDL-C/HDL-C
and TC/HDL-C increased in groups 3 and 4 compared with time 0, the
increase being smaller in group 4 than in group 3. Serum HDL-C
decreased in group 3 and increased in group 4 compared with time 0, but
changes were lower in group 3 than in group 4. SDG reduced TC and LDL-C
by 33% and 35%, respectively, at week 8 but increased HDL-C
significantly, by>140%, as early as week 4. It also decreased
TC/LDL-C and LDL-C/HDL-C ratios by 
64%. There was an increase in
aortic malondialdehyde and chemiluminescence in group 3, and they were
lower in group 4 than in group 3. SDG reduced
hypercholesterolemic atherosclerosis by
73%.
Conclusions—These results suggest that SDG reduced hypercholesterolemic atherosclerosis and that this effect was associated with a decrease in serum cholesterol, LDL-C, and lipid peroxidation product and an increase in HDL-C and antioxidant reserve.
Key Words: atherosclerosis • hypercholesterolemia • flaxseed • chemiluminescence • antioxidants
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Introduction |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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Oxygen free radicals (OFRs) have been implicated in the development of hypercholesterolemic atherosclerosis.1 2 3 Polymorphonuclear leukocytes (PMNLs) seem to be one of the sources of OFRs during hypercholesterolemia.1 2 Hypercholesterolemia could increase the release of platelet-activating factor (PAF),2 which in turn could increase the synthesis and release of interleukin-14 and tumor necrosis factor.5 Leukotriene B4,6 PAF,7 interleukin-1,8 and tumor necrosis factor9 are known to stimulate PMNLs to produce OFRs, which would initiate the development of hypercholesterolemic atherosclerosis.
Flaxseed contains 35% of its mass as oil, of which 55% is
-linolenic acid (
-3 fatty acid) and 15% to 18% is
linoleic acid.10 11 It is a rich source of -3 fatty
acids and the richest source of plant lignans.12 13
Flaxseed has been shown to be effective in reducing
hypercholesterolemic atherosclerosis by
46% without lowering serum cholesterol.14
Crop Development Center (CDC)-flaxseed, which has an oil content
(35% of total mass) and concentrations of lignan secoisolariciresinol
diglucoside (SDG) (16.4 mg/g versus 15.4 mg/g defatted meal) similar to
those of ordinary flaxseed but has only 2% to 3% of
-linolenic acid content, reduced the development of
hypercholesterolemic atherosclerosis by
69% and reduced serum cholesterol and LDL
cholesterol (LDL-C) by 31% to 32%.15
These results suggest that the antiatherogenic activity of flaxseed is
not due to -linolenic acid but may be due to the lignan
component of the meal.
Recently, methods have been developed by Agriculture and Agri-Food
Canada, a member of our "Flaxseed-Lignan Research Consortium," to
produce SDG (>95% pure) in large quantities (Westcott and
Muir16 ). The level of SDG in flaxseed varies
between 0.6 and 1.8 g/100 g. The chemical structure of SDG is shown in
Figure 1
. Its molecular weight is 686.71.
Because of its anti-PAF activity,17 SDG would inhibit
PAF-induced release of OFRs by PMNLs, and because of its antioxidant
activity,18 it would remove OFRs produced by cells in the
body. Hypercholesterolemic
atherosclerosis is associated with an increase in the
lipid peroxidation product malondialdehyde (MDA), an index of
levels of OFRs, and a decrease in antioxidant reserve of the
aorta.1 2 Reduction in atherosclerosis by
antioxidants was associated with a decrease in MDA and an increase in
antioxidant reserve of the aorta.1 2 It is hypothesized
that SDG, which has anti-PAF and antioxidant activity, would prevent
development of hypercholesterolemic
atherosclerosis. An investigation was therefore made of
the effects of a high-cholesterol diet in rabbits with or
without SDG treatment on the genesis of
atherosclerosis, serum lipid profile
[triglycerides (TG), total cholesterol (TC),
HDL cholesterol (HDL-C), LDL-C, VLDL
cholesterol (VLDL-C)], aortic tissue MDA, and antioxidant
reserve. Gross and microscopic changes in the aorta were also
investigated. Because the TC/HDL-C and LDL-C/HDL-C ratios determine the
relative risk of coronary artery disease, they were also
calculated.
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Methods |
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New Zealand White rabbits 6 to 8 weeks old weighing between 1.8 and 2.0 kg, after 1 week of adaptation, were assigned to 4 groups as shown in Table 1
. Those in group 1
were fed rabbit laboratory chow pellets. The other groups received SDG
or cholesterol or cholesterol plus SDG in
addition to rabbit chow, as shown in Table 1. The diet was specially
prepared by Purina and did not contain any antioxidants. SDG (15 mg/kg
body wt) was fed orally, wrapped in leafy vegetables (lettuce). Water
was given ad libitum. The rabbits were housed in cages under a
12-hour-light/12-hour-dark cycle according to approved standards for
laboratory animal care. The rabbits were anesthetized at the
end of 8 weeks, and aortas were removed under pentobarbital sodium
anesthesia (40 mg/kg IV) for assessment of atherosclerotic
plaques and measurement of tissue MDA and antioxidant reserve. Blood
samples (from ear marginal artery) for measurement of serum TG, TC,
HDL-C, LDL-C, and VLDL-C were collected before (time 0) and after 4 and
8 weeks on the respective experimental diets. No food was supplied for
18 hours before withdrawal of blood samples. Weights of the rabbits
were recorded at 0, 4, and 8 weeks.
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Serum TG and Cholesterol
As previously described,15 an automated chemistry
analyzer (Hitachi model 717, Boehringer Mannheim) was
used to measure serum TG, TC, and HDL-C. VLDL-C was calculated as the
concentration of TG divided by 2.2.19 Serum LDL-C was
calculated by subtracting the sum of HDL-C and VLDL-C from total
cholesterol.20
Preparation of Aortic Tissue Homogenate and
Supernatant
Aortas (between the origin and bifurcation of iliac arteries)
were removed, cleaned of gross adventitial tissue, and divided
longitudinally into 2 halves. One half was used for estimation of
atherosclerotic plaques and histology. The other half was used to
prepare homogenate and supernatant by a previously
described method.2
MDA (Thiobarbituric Acid–Reactive Substances)
MDA levels in the homogenate were measured as
thiobarbituric acid–reactive substances as previously
described.21 22 Thiobarbituric acid–reactive substances
were extracted in a mixture of butanol and pyridine, which was
separated by centrifugation. The fluorescence
intensity of the butanol/pyridine solution was measured at 553 nm with
excitation at 513 nm. The MDA content of the aortic tissue was
expressed as nmol/mg protein.
Aortic Tissue Chemiluminescence
Aortic tissue chemiluminescence (AO-CL), a measure of
antioxidant reserve, was measured as previously
described.2 An increase in tissue CL indicates a decrease
in antioxidant reserve of tissue and vice versa. Antioxidant reserve is
the amount of antioxidant present in the tissue at the time of
exposure of the tissue to oxidants. Aortic tissue supernatant (0.8 mL)
was added to a counting vial containing 0.4 mL of
2x10-4 mol/L luminol and placed in a
luminometer at 37°C. Reaction was initiated by adding 0.2 mL of
2x10-1 mol/L tert-butyl hydroperoxide (t-BHP).
The CL for each sample was determined with or without t-BHP. The
difference in the areas with and without t-BHP was designated as
luminol-amplified CL (t-BHP–derived oxyradicals). The CL was expressed
as mV · s-1 · mg
protein-1.
Assessment of Atherosclerotic Plaques
The atherosclerotic plaques were assessed with Herxheimer's
solution as previously described.1 23 The surface area of
atheromatous lesions was measured from a photograph of
the aorta and expressed as a percentage of total aortic intimal surface
area. Small portions of the plaques and adjacent normal aortic area
from groups 3 and 4 and from comparable areas of aorta from groups 1
and 2 were cut across and embedded in paraffin. Paraffin sections of
aorta were cut and stained with hematoxylin–oil red O for lipid
deposit and Verhoeff–van Gieson's stain for elastic fibers and for
morphological assessment of atherosclerotic
lesions.1 24
Statistical Analysis
Results are expressed as mean±SEM. Repeated-measures ANOVA was
used for statistical analysis of blood lipid data and body
weight. The Kruskal-Wallis test was used to test the differences in the
atherosclerotic change in the 4 groups. The Mann-Whitney U
test was used to determine the significance of differences between any
2 groups. Type I error for multiple comparison was controlled by
Bonferroni correction. A value of P<0.05 was considered
significant.
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Results |
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Body Weight
The changes in the body weights of the rabbits of the experimental groups are shown in Table 2
. There was a
progressive increase in the body weight of all groups. The weight gains
in groups 2, 3, and 4 were similar but lower than in group 1.
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Triglycerides
Initial values for serum TG were similar in all groups except
group 4, in which the values were lower than in group 3. Changes in TG
level in the 4 groups are summarized in Figure 2. TG decreased in groups 1 and 2 at
weeks 4 and 8 compared with time 0 but remained practically unchanged
in the other groups. Values in groups 1 and 2 were lower than those in
groups 3 and 4 at weeks 4 and 8.
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Cholesterol and Lipoproteins
Initial values for serum cholesterol in groups 1, 2,
3, and 4 were 2.26±0.20, 1.42±0.11, 2.68±0.20, and
2.26±0.25 mmol/L, respectively, and were not significantly
different from each other except for that in group 2, which was lower
than in the other groups. The results are summarized in Figure 3. Values remained unchanged in groups 1
and 2 at weeks 4 and 8 but increased markedly in groups 3 and 4, those
in group 4 at week 8 being lower than those in group 3. Initial values
for serum LDL-C in groups 1, 2, 3, and 4 were 0.90±0.10, 0.34±0.09,
1.22±0.17, and 1.09±0.19 (SEM) mmol/L, respectively. The results
are summarized in Figure 4. Values
remained unchanged in groups 1 and 2 compared with time 0 but increased
in groups 3 and 4 at weeks 4 and 8, the increase being greater in group
3 than in group 4 at week 8.
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Initial values for serum HDL-C were similar in all groups. The changes
in values of serum HDL-C are summarized in Figure 5. Values for HDL-C remained unchanged in
groups 1 and 2 throughout the period of observation compared with time
0 but decreased in group 3 and increased in group 4 at week 4 only.
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The changes in the values for VLDL-C are shown in Figure 6. Initial values were similar in all
groups except group 3, in which it was higher than in groups 1 and 4.
It decreased in groups 1 and 2 at weeks 4 and 8 and group 3 at week 8
but remained unchanged in group 4 compared with time 0.
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Initial values of TC/HDL-C ratio were 3.27±0.21, 2.55±0.20,
3.81±0.27, and 3.74±0.24 in groups 1, 2, 3, and 4, respectively, and
were not significantly different from each other. Initial values of the
LDL-C/HDL-C ratio in groups 1, 2, 3, and 4 were 1.31±0.112,
0.570±0.155, 1.73±0.225, and 1.75±0.322, respectively. Values in
groups 3 and 4 were higher and in group 2 were lower than in group 1.
Changes in the TC/HDL-C and LDL-C/HDL-C ratios are summarized in Figure 7. These ratios remained unchanged
throughout the period of observation in groups 1 and 2 but increased in
groups 3 and 4 compared with time 0. The increases in group 4 were
smaller than those in group 3.
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P<0.05, group
1 vs other groups. aP<0.05, group 2 vs groups 3
and 4. bP<0.05, group 3 vs group 4.
Aortic Tissue MDA
The MDA content of aortic tissue from the 4 groups is summarized
in Figure 8A. It was 0.09±0.01 nmol/mg
protein in group 1. The level was lower in group 2, but not
significantly so, and higher in groups 3 and 4 than in group 1. The
levels of MDA were lower in group 4 than in group 3.
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Aortic Tissue CL
The AO-CL in the 4 groups is summarized in Figure 8B
. The
value for chemiluminescent activity in group 1 was 8058±619 (SEM)
mV · s-1 · mg
protein-1. It increased in group 3 compared with
group 1 or 2 but decreased in group 4 compared with group 3.
Atherosclerotic Changes in Aorta
Representative photographs of
endothelial surfaces of aortas from each group are
shown in Figure 9, and the results are
summarized in Figure 10.
Atherosclerotic plaques were absent in groups 1 and 2. However, a
significant area of aortic intimal surface from group 3 (78.97±5.44%)
and group 4 (21.69±2.06%) was covered with atherosclerotic plaques.
In group 4, the atherosclerotic plaques were significantly smaller than
those in group 3. SDG reduced the hypercholesterolemic
atherosclerosis by 73%. Atherosclerotic plaques were
distributed all over the aorta in group 3 but were present mainly
in the proximal segment of the aorta and at the opening of the vasa
vasorum in group 4.
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Histological sections of aorta stained with
hematoxylin–oil red O and Verhoeff–van Gieson's stain from the 4
groups are shown in Figures 11 and 12, respectively.
Histological sections through the atherosclerotic
plaques of aortas from groups 3 and 4 showed thickening of the intima,
which consisted of foam cells that contained oil red O–stainable lipid
(Figure 11). The internal elastic lamina and elastic fibers in
the subintimal media were intact and arranged in normal fashion (Figure 12). The overall thickness of the media increased in groups 3
and 4 compared with groups 1 and 2, being greater in group 3 than in
group 4. The histological changes in groups 3 and 4
were qualitatively similar.
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Discussion |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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The lower weight gains in groups 2, 3, and 4 compared with group 1 cannot be explained at present. It could not be due to SDG, because group 3, which did not have SDG in the diet, had a weight gain similar to that of group 4, which had SDG in the diet.
A high-cholesterol diet produced an increase in serum TC, LDL-C, and TC/HDL-C and LDL-C/HDL-C ratios and a decrease in HDL-C. Serum TG and VLDL-C remained unaffected. Qualitatively similar changes have been reported in earlier studies.1 2 25 In the present study, SDG reduced the levels of serum cholesterol and LDL-C and the TC/HDL-C and LDL-C/HDL-C ratios but increased the levels of HDL-C as early as 4 weeks in cholesterol-fed rabbits. The mechanism of these changes with SDG is not known. It should be noted that we have shown flaxseed to increase serum cholesterol, LDL-C, and VLDL-C in a high-cholesterol diet.14
The aortic MDA increased in rabbits fed the high-cholesterol diet but was decreased with SDG treatment. We have previously reported increases in aortic MDA in hypercholesterolemic rabbits.1 2 No data are available in the literature for the effect of SDG on the level of aortic tissue MDA in hypercholesterolemic or normocholesterolemic rabbits. The decrease in MDA levels could be due to the antioxidant activity of SDG.18
An increase of AO-CL in rabbits fed a high-cholesterol diet suggests a decrease in antioxidant reserves, whereas a decrease in AO-CL with SDG treatment suggests an increase in the levels of antioxidant reserve. The increase in antioxidant reserve with SDG could be due to a reduction in oxidative stress because of the antioxidant activity of SDG.18 An increase in the antioxidant reserve of aortic tissue in hypercholesterolemic rabbits has been observed with antioxidants such as probucol2 and purpurogallin.25
The severity of the atheromatous lesions in aorta was associated with hypercholesterolemia. We and other investigators1 2 26 27 have made similar observations. Hypercholesterolemic diet produced intimal thickening that contained foam cells similar to that observed by others.1 2 27 SDG reduced the extent of development of atherosclerosis in hypercholesterolemic rabbits. The protective effect of SDG could be attributed to its antioxidant activity, because it reduced levels of MDA and increased the antioxidant reserve in aortic tissue. SDG-induced decreases in serum TC and LDL-C and increases in HDL-C in hypercholesterolemic rabbits could also contribute to a reduction in atherosclerosis.
Hypercholesterolemic atherosclerosis was associated with an increase in aortic tissue MDA and a decrease in the antioxidant reserve. Increased aortic tissue MDA suggests an increase in the levels of OFRs, which may be due to increased production and/or decreased antioxidant reserve. Increased levels of OFRs may be due to increased production by PMNLs,1 endothelial cells, and other blood-borne or vessel-wall cells28 and during prostaglandin29 and leukotriene30 synthesis. A decrease in antioxidant reserve may also lead to increased levels of OFRs, which are known to produce endothelial cell injury.31 Endothelial cell injury represents a critical initiating event in the development of atherosclerosis.32 SDG may have prevented OFR-induced endothelial-cell injury through its antioxidant activity. Further studies with various dosages of SDG and for long durations are planned. This compound needs to be tested in human beings after animal studies are completed.
In conclusion, these results suggest that hypercholesterolemic atherosclerosis is associated with an increase in oxidative stress in aorta and that SDG is effective in reducing hypercholesterolemic atherosclerosis by reducing oxidative stress and lowering serum levels of cholesterol and LDL-C and raising serum levels of HDL-C in the early stage. SDG therefore may be useful in preventing hypercholesterolemic atherosclerosis and lowering the relative risk of coronary artery disease.
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Acknowledgments |
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This work was supported by the Heart and Stroke Foundation of Saskatchewan. The author acknowledges the technical assistance of P.K. Chattopadhyay and P. Lee. The author is also grateful to Drs A.D. Muir and N.D. Westcott of Agriculture and Agri-Food Canada (AAFC), Saskatoon, for providing SDG.
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Footnotes |
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Reprint requests to K. Prasad, MD, PhD, FRCPC, FACC, Department of Physiology, College of Medicine, University of Saskatchewan, 107 Wiggins Rd, Saskatoon, Saskatchewan, Canada S7N 5E5.
Received May 29, 1998; revision received November 9, 1998; accepted November 11, 1998.
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References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
-
Prasad K, Kalra J. Oxygen free radicals and
hypercholesterolemic atherosclerosis:
effect of vitamin E. Am Heart J. 1993;125:958–973.[Medline]
[Order article via Infotrieve]
-
Prasad K, Kalra J, Lee P. Oxygen free radicals as a
mechanism of hypercholesterolemic
atherosclerosis: effects of probucol. Int J
Angiol. 1994;3:100–112.
-
Steinberg D. Antioxidants in the prevention of human
atherosclerosis. Circulation. 1992;85:2338–2345.
-
Pignol B, Henane S, Mencia-Huerta JM,
Rola-Pleszczynski M, Braquet P. Effect of platelet-activating
factor (PAF-acether) and its specific receptor antagonist,
BN 52021, on interleukin 1 (IL1) release and synthesis by rat spleen
adherent monocytes. Prostaglandins. 1987;33:931–939.[Medline]
[Order article via Infotrieve]
-
Bonavida B, Mencia-Huerta JM, Braquet P. Effect of
platelet-activating factor on monocyte activation and
production of tumor necrosis factor. Int Arch Allergy
Appl Immunol. 1989;88:157–160.[Medline]
[Order article via Infotrieve]
-
Sumimoto H, Takeshige K, Minakami S. Superoxide
production of human polymorphonuclear leukocytes stimulated
by leukotriene B4. Biochim
Biophys Acta. 1984;803:271–277.[Medline]
[Order article via Infotrieve]
-
Shaw JO, Pinckard RN, Ferrigni KS, McManus LM, Hanahan
DJ. Activation of human neutrophils with
1-O-hexadecyl/octadecyl-2-actyl-sn-glycerol-3-phosphorylcholine
(platelet-activating factor). J Immunol. 1981;127:1250–1255.[Abstract]
-
Braquet P, Hosford D, Braquet M, Bourgain R, Bussolino
F. Role of cytokines and platelet-activating factor in
microvascular immune injury. Int Arch Allerg Appl Immunol. 1989;88:88–100.[Medline]
[Order article via Infotrieve]
-
Paubert-Braquet M, Lonchampt MO, Koltz P, Guilbaud J.
Tumor necrosis factor (TNF) primes human neutrophil (PMN)
platelet-activating factor (PAF)-induced superoxide generation:
consequences in promoting PMN-mediated endothelial cell
(EC) damages. Prostaglandins. 1988;35:803.
Abstract.
-
Carter J. Flax seed as a source of alpha
linolenic acid. J Am Coll Nutr. 1993;12:551.[Medline]
[Order article via Infotrieve]
-
Cunnane SC, Ganguli S, Menard C, Liede AC, Hamadeh MJ,
Chen Z-Y, Wolever TMS, Jenkins DJA. High alpha-linolenic acid
flaxseed (Linum usit atissimum): some nutritional properties
in humans. Br J Nutr. 1993;69:443–453.[Medline]
[Order article via Infotrieve]
-
Hunter JE. n-3 fatty acids from vegetable oils.
Am J Clin Nutr. 1990;51:809–814.
[Abstract/Free Full Text]
-
Bakke JE, Klosterman HJ. A new diglucoside from
flaxseed. Proc North Dakota Acad Sci. 1956;10:18–22.
-
Prasad K. Dietary flaxseed in the prevention of
hypercholesterolemic atherosclerosis.
Atherosclerosis. 1997;132:69–76.[Medline]
[Order article via Infotrieve]
-
Prasad K, Mantha SV, Muir AD, Westcott ND. Reduction of
hypercholesterolemic atherosclerosis by
CDC-flaxseed with very low alpha-linolenic acid.
Atherosclerosis. 1998;136:367–375.[Medline]
[Order article via Infotrieve]
-
Westcott ND, Muir AD. Process for Extracting
Lignans From Flaxseed. US patent 5 705 618, January 6,
1998.
-
Cox CP, Wood KL. Selective antagonism of
platelet-activating factor (PAF)-induced aggregation and secretion
of washed rabbit platelets by CV-3988, L-652731, triazolam and
alprazolam. Thromb Res. 1987;47:249–257.[Medline]
[Order article via Infotrieve]
-
Prasad K. Hydroxyl radical scavenging property of
secoisolariciresinol diglucoside (SDG) isolated from flaxseed.
Mol Cell Biochem. 1997;168:117–123.[Medline]
[Order article via Infotrieve]
-
Wilson PW, Abbot RD, Garrison RJ, Castelli WP.
Estimation of very low-density lipoprotein cholesterol from
data on triglyceride concentrations in plasma. Clin
Chem. 1981;27:2008–2010.
[Abstract/Free Full Text]
-
Friedwald WT, Levy RRI, Fredrickson DS. Estimation of
the concentration of low-density lipoprotein cholesterol in
plasma without the use of preparative ultracentrifuge.
Clin Chem. 1972;18:499–502.[Abstract]
-
Kapoor R, Prasad K. Role of oxyradicals in
cardiovascular depression and cellular injury in
hemorrhagic shock and reinfusion: effect of SOD and catalase.
Circ Shock. 1994;43:79–94.[Medline]
[Order article via Infotrieve]
-
Ohkawa H, Ohishi N, Yagi K. Assay for lipid peroxides
in animal tissue by thiobarbituric acid reaction. Anal
Biochem. 1979;95:351–358.[Medline]
[Order article via Infotrieve]
-
Holman RS, McGill HC Jr, Strong JP, Greer JC. Technics
for studying atherosclerotic lesions. Lab Invest. 1958;7:42–47.[Medline]
[Order article via Infotrieve]
-
Drury RAB, Wallington EA. Carleson's
Histological Technique. 5th ed. New York, NY:
Oxford University Press; 1980:195, 291.
-
Prasad K, Mantha SV, Kalra J, Kapoor R, Kamalarajan
BRC. Purpurogallin in the retardation of
hypercholesterolemic atherosclerosis.
Int J Angiol. 1997;6:157–166.
-
Pearson TA, Malros H, Dillman J, Sternby N, Heptinstall
RH. Atherosclerosis in
hypercholesterolemic hare: comparison of
coronary artery lesions induced by dietary
cholesterol in the hare and rabbit.
Atherosclerosis. 1987;63:125–135.[Medline]
[Order article via Infotrieve]
-
Rouleau JL, Parmley WW, Stevens J, Wikman-Coffelt J,
Sievers R, Mahley RW, Havel RJ, Brecht W. Verapamil
suppresses atherosclerosis in cholesterol
fed rabbits. J Am Coll Cardiol. 1983;1:1453–1460.[Abstract]
-
Warren JS, Ward PA. Oxidative injury to vascular
endothelium. Am J Med Sci. 1983;292:97–103.
-
Egan RW, Paxton J, Kuehl FA Jr. Mechanism for
irreversible self-deactivation of prostaglandin synthesis.
J Biol Chem. 1976;251:7329–7335.
[Abstract/Free Full Text]
-
Murota SI, Morita I, Suda N. The control of vascular
endothelial cell injury. Ann N Y Acad Sci. 1990;598:182–187.[Abstract]
-
Sacks T, Moldow CF, Graddock PR, Bowers TK, Jacob HS.
Oxygen radicals mediate endothelial cell damage by
complement-stimulated granulocytes: an in vitro model of immune
vascular damage. J Clin Invest. 1978;61:1161–1167.
-
Ross R. The pathogenesis of
atherosclerosis: an update. N Engl J
Med. 1986;314:488–500.[Medline]
[Order article via Infotrieve]
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 T. Clavel, G. Henderson, C.-A. Alpert, C. Philippe, L. Rigottier-Gois, J. Dore, and M. Blaut Intestinal Bacterial Communities That Produce Active Estrogen-Like Compounds Enterodiol and Enterolactone in Humans Appl. Envir. Microbiol., October 1, 2005; 71(10): 6077 - 6085. [Abstract] [Full Text] [PDF]
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 R. M. Lane and M. R. Farlow Lipid homeostasis and apolipoprotein E in the development and progression of Alzheimer's disease J. Lipid Res., May 1, 2005; 46(5): 949 - 968. [Abstract] [Full Text] [PDF]
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C. Stuglin and K. Prasad Effect of Flaxseed Consumption on Blood Pressure, Serum Lipids, Hemopoietic System and Liver and Kidney Enzymes in Healthy Humans Journal of Cardiovascular Pharmacology and Therapeutics, January 1, 2005; 10(1): 23 - 27. [Abstract] [PDF]
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K. Prasad C-Reactive Protein Increases Oxygen Radical Generation by Neutrophils Journal of Cardiovascular Pharmacology and Therapeutics, July 1, 2004; 9(3): 203 - 209. [Abstract] [PDF]
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P. Lee and K. Prasad Effects of Flaxseed Oil on Serum Lipids and Atherosclerosis in Hypercholesterolemic Rabbits Journal of Cardiovascular Pharmacology and Therapeutics, September 1, 2003; 8(3): 227 - 235. [Abstract] [PDF]
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 S. J. Bhathena, A. A. Ali, C. Haudenschild, P. Latham, T. Ranich, A. I. Mohamed, C. T. Hansen, and M. T. Velasquez Dietary Flaxseed Meal is More Protective Than Soy Protein Concentrate Against Hypertriglyceridemia and Steatosis of the Liver in an Animal Model of Obesity J. Am. Coll. Nutr., April 1, 2003; 22(2): 157 - 164. [Abstract] [Full Text] [PDF]
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K. Prasad and P. Lee Suppression of Oxidative Stress as a Mechanism of Reduction of Hypercholesterolemic Atherosclerosis by Aspirin Journal of Cardiovascular Pharmacology and Therapeutics, March 1, 2003; 8(1): 61 - 69. [Abstract] [PDF]
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 S. J Bhathena and M. T Velasquez Beneficial role of dietary phytoestrogens in obesity and diabetes Am. J. Clinical Nutrition, December 1, 2002; 76(6): 1191 - 1201. [Abstract] [Full Text] [PDF]
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 M. S. Anthony Phytoestrogens and Cardiovascular Disease: Where's the Meat? Arterioscler. Thromb. Vasc. Biol., August 1, 2002; 22(8): 1245 - 1247. [Full Text] [PDF]
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 E. A. Lucas, R. D. Wild, L. J. Hammond, D. A. Khalil, S. Juma, B. P. Daggy, B. J. Stoecker, and B. H. Arjmandi Flaxseed Improves Lipid Profile without Altering Biomarkers of Bone Metabolism in Postmenopausal Women J. Clin. Endocrinol. Metab., April 1, 2002; 87(4): 1527 - 1532. [Abstract] [Full Text] [PDF]
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