Effects of lactic acid bacteria on low-density lipoprotein susceptibility to oxidation and aortic fatty lesion formation in hyperlipidemic hamsters

2015 ◽  
Vol 6 (3) ◽  
pp. 287-293 ◽  
Author(s):  
M. Ito ◽  
K. Oishi ◽  
Y. Yoshida ◽  
T. Okumura ◽  
T. Sato ◽  
...  

We investigated the effects of Streptococcus thermophilus YIT 2001, a strain of lactic acid bacteria, on the susceptibility of low-density lipoprotein (LDL) to oxidation and the formation of aortic fatty lesions in hyperlipidemic hamsters. S. thermophilus YIT 2001 had the highest in vitro antioxidative activity against LDL oxidation among the 79 strains of lactic acid bacteria and bifidobacteria tested, which was about twice that of S. thermophilus YIT 2084. The lag time of LDL oxidation in the YIT 2001 feeding group was significantly longer than in controls, but was unchanged in the YIT 2084 group. After the feeding of YIT 2001, lag times were prolonged and areas of aortic fatty lesions were dose-dependently attenuated, although there were no effects on plasma lipid levels. These results suggest that YIT 2001 has the potential to prevent the formation of aortic fatty lesions by inhibiting LDL oxidation.

2007 ◽  
Vol 77 (1) ◽  
pp. 66-72 ◽  
Author(s):  
McEneny ◽  
Couston ◽  
McKibben ◽  
Young ◽  
Woodside

Raised total homocysteine (tHcy) levels may be involved in the etiology of cardiovascular disease and can lead to damage of vascular endothelial cells and arterial wall matrix. Folic acid supplementation can help negate these detrimental effects by reducing tHcy. Recent evidence has suggested an additional anti-atherogenic property of folate in protecting lipoproteins against oxidation. This study utilized both an in vitro and in vivo approach. In vitro: Very-low-density lipoprotein (VLDL) and low density lipoprotein (LDL) were isolated by rapid ultracentrifugation and then oxidized in the presence of increasing concentrations (0→ μmol/L) of either folic acid or 5-methyltetrahydrofolate (5-MTHF). In vivo: Twelve female subjects were supplemented with folic acid (1 mg/day), and the pre- and post-VLDL and LDL isolates subjected to oxidation. In vitro: 5-MTHF, but not folic acid, significantly increased the resistance of VLDL and LDL to oxidation. In vivo: Following folic acid supplementation, tHcy decreased, serum folate increased, and both VLDL and LDL displayed a significant increase in their resistance to oxidation. These results indicated that in vitro, only the active form of folate, 5-MTHF, had antioxidant properties. In vivo results demonstrated that folic acid supplementation reduced tHcy and protected both VLDL and LDL against oxidation. These findings provide further support for the use of folic acid supplements to aid in the prevention of atherosclerosis.


2005 ◽  
Vol 109 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Mike J. Sampson ◽  
Simon Braschi ◽  
Gavin Willis ◽  
Sian B. Astley

The HDL (high-density lipoprotein)-associated enzyme PON (paraoxonase)-1 protects LDL (low-density lipoprotein) from oxidative modification in vitro, although it is unknown if this anti-atherogenic action occurs in vivo. In a cross-sectional study of 58 Type II diabetic subjects and 50 controls, we examined the fasting plasma LDL basal conjugated diene concentration [a direct measurement of circulating oxLDL (oxidatively modified LDL)], lipoprotein particle size by NMR spectroscopy, PON-1 polymorphisms (coding region polymorphisms Q192R and L55M, and gene promoter polymorphisms −108C/T and −162G/A), PON activity (with paraoxon or phenyl acetate as the substrates) and dietary antioxidant intake. Plasma oxLDL concentrations were higher in Type II diabetic patients (males, P=0.048; females, P=0.009) and unrelated to NMR lipoprotein size, PON-1 polymorphisms or PON activity (with paraoxon as the substrate) in any group. In men with Type II diabetes, however, there was a direct relationship between oxLDL concentrations and PON activity (with phenyl acetate as the substrate; r=0.611, P=0.0001) and an atherogenic NMR lipid profile in those who were PON-1 55LL homozygotes. Circulating oxLDL concentrations in vivo were unrelated to PON-1 genotypes or activity, except in male Type II diabetics where there was a direct association between PON activity (with phenyl acetate as the substrate) and oxLDL levels. These in vivo data contrast with in vitro data, and may be due to confounding by dietary fat intake. Male Type II diabetic subjects with PON-1 55LL homozygosity have an atherogenic NMR lipid profile independent of LDL oxidation. These data do not support an in vivo action of PON on LDL oxidation.


1992 ◽  
Vol 38 (10) ◽  
pp. 2066-2072 ◽  
Author(s):  
H A Kleinveld ◽  
H L Hak-Lemmers ◽  
A F Stalenhoef ◽  
P N Demacker

Abstract Low-density-lipoprotein (LDL) oxidation may provide the crucial link between plasma LDL and atherosclerotic-lesion formation. Oxidation can be induced in vitro by incubating LDL with cells or metal ions and can be measured by continuously monitoring conjugated-diene absorbance at 234 nm. Measurement of LDL oxidizability was improved by performing the assay with 0.05 g of LDL-protein per liter of phosphate buffer containing 1 mumol of EDTA, by initiating oxidation by adding CuCl2 (5 mumol/L) at 30 degrees C, and by using a short-run ultracentrifugation method for isolating LDL, which reduced the time needed for obtaining purified LDL and thus reduced in vitro oxidation. LDL apolipoprotein analysis and oxidizability determination showed that this method is better than the longer sequential-isolation procedure. Adding butylated hydroxytoluene (BHT) to plasma as an antioxidant unpredictably increased the LDL oxidation lag time, making BHT unsuitable as an antioxidant. Adding EDTA appeared to be sufficient to prevent in vitro oxidation. Additionally, the diene production correlated highly with the concentration of thiobarbituric acid-reactive substances (r = 0.97). No relation between the vitamin E content of LDL and the oxidation lag time was found.


1996 ◽  
Vol 42 (4) ◽  
pp. 524-530 ◽  
Author(s):  
R Siekmeier ◽  
P Wülfroth ◽  
H Wieland ◽  
W Gross ◽  
W März

Abstract We analyzed the susceptibility of low-density lipoproteins (LDL) to oxidation in 17 healthy smokers (43.3 +/- 16.8 pack-years) and 19 healthy nonsmokers, matched for age (smokers: 52 +/- 7 years; nonsmokers: 53 +/- 7 years), gender, and relative body mass. Cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, and apolipoprotein (apo) B were not different between smokers and nonsmokers; apo A-I was slightly lower in smokers (one-tailed P = 0.066). To study whether LDL from smokers were prone to in vitro oxidation than LDL from nonsmokers, we measured the time kinetics of diene formation and the production of malondialdehyde during oxidation of LDL in vitro. In smokers and nonsmokers, respectively, the mean (+/-SD) lag times (tinh) of diene formation were 111 +/- 26 and 100 +/- 27 min, the peak rates of diene formation (Vmax) were 5.99 +/- 2.34 and 6.34 +/- 2.30 mmol x min-1 x g-1, and the amounts of dienes produced during the propagation phase (dmax) were 250 +/- 264 and 248 +/- 56 mmol x g-1. Neither the malondialdehyde content of LDL (measured as thiobarbituric acid-reactive substances) before oxidation nor the amount of malondialdehyde generated during oxidation (smokers: 57.0 +/- 14.2 micromol x g-1; nonsmokers: 63.2 +/- 15.2 micromol x g-1 indicated any statistically significant effect of smoking. When nonsmokers and smokers were considered together, the amount of malondialdehyde generated during oxidation correlated with age (nonparametric rs = 0.405), body mass index (r2 = 0.573), and concentrations of apo B (rs = 0.480), cholesterol (rs = 0.448), triglycerides (rs = 0.436), and LDL cholesterol (rs = 0.398). Our data show that smoking is not associated with increased oxidizability of LDL in healthy men and women at ages 42-63 years.


Metabolism ◽  
2000 ◽  
Vol 49 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Mitsunobu Kawamura ◽  
Shigeru Miyazaki ◽  
Tamio Teramoto ◽  
Keiko Ashidate ◽  
Hisako Thoda ◽  
...  

1996 ◽  
Vol 313 (3) ◽  
pp. 781-786 ◽  
Author(s):  
Jaffar NOUROOZ-ZADEH ◽  
Jarad TAJADDINI-SARMADI ◽  
K. L. Eddie LING ◽  
Simon P. WOLFF

High-density lipoprotein (HDL) has been proposed as the principal carrier of hydroperoxides in plasma, based upon data gathered with an HPLC-chemiluminescence technique. To test this hypothesis we have measured total lipid hydroperoxides in native plasma using the ferrous oxidation in Xylenol Orange (FOX) assay and then fractionated plasma into very-low-density lipoprotein, low-density lipoprotein (LDL) and HDL fractions. Hydroperoxides were found to accumulate principally (more than 65%) in LDL, as judged by hydroperoxide content per amount of protein or cholesterol, or expressed as a proportion of total hydroperoxide in plasma. Plasma was also incubated at 37 °C in the presence and absence of 2,2´-azo-bis-(2-amidinopropane) hydrochloride (AAPH), an azo-initiator of lipid peroxidation. The majority of hydroperoxides generated in plasma were recovered in the LDL fraction. Furthermore, when isolated lipoproteins were subject to oxidation initiated by AAPH, very-low-density lipoprotein and LDL showed the greatest propensity for hydroperoxide accumulation, whereas HDL seemed relatively resistant. Estimates for plasma and LDL peroxidation based upon techniques which measure total lipid hydroperoxides suggest that levels of hydroperoxides in plasma and LDL are far higher than that those estimates generated by ostensibly more selective techniques. Higher levels of hydroperoxides in LDL than those reported by HPLC-chemiluminescence also seem in greater accordance with other available data concerning LDL oxidation.


1994 ◽  
Vol 300 (1) ◽  
pp. 243-249 ◽  
Author(s):  
J V Hunt ◽  
M A Bottoms ◽  
K Clare ◽  
J T Skamarauskas ◽  
M J Mitchinson

The exposure of proteins to high concentrations of glucose in vitro is widely considered a relevant model of the functional degeneration of tissue occurring in diabetes mellitus. In particular, the enhanced atherosclerosis in diabetes is often discussed in terms of glycation of low-density lipoprotein (LDL), the non-enzymic attachment of glucose to apolipoprotein amino groups. However, glucose can undergo transition-metal-catalysed oxidation under near-physiological conditions in vitro, producing oxidants that possess a reactivity similar to the hydroxyl radical. These oxidants can fragment protein, hydroxylate benzoic acid and induce lipid peroxidation in human LDL. In this study, glycation of LDL in vitro is accompanied by such oxidative processes. However, the oxidation of LDL varies with glucose concentration in a manner which does not parallel changes in protein glycation. Glycation increases in proportion to glucose concentration, whereas in our studies maximal oxidation occurs at a glucose concentration of approx. 25 mM. The modification of LDL resulting from exposure to glucose alters macrophage ceroid accumulation, a process which occurs in the human atherosclerotic plaque. The accumulation of ceroid in macrophages is shown to be related to LDL oxidation rather than LDL glycation, per se, as it too occurs at a maximum of approx. 25 mM. Oxidative sequelae of protein glycation appear to be a major factor in LDL-macrophage interactions, at least with respect to ceroid accumulation. Our observations are discussed in the context of the observed increase in the severity of atherosclerosis in diabetes.


2018 ◽  
Vol 9 (1) ◽  
pp. 143-152 ◽  
Author(s):  
S. Kusuhara ◽  
M. Ito ◽  
T. Sato ◽  
W. Yokoi ◽  
Y. Yamamoto ◽  
...  

Streptococcus thermophilus YIT 2001 (ST-1), a lactic acid bacterial strain, was shown to have inhibitory effects on the oxidation of low-density lipoprotein (LDL) and the development of aortic fatty lesions in an animal model, and lower the serum levels of malondialdehyde-modified LDL, an oxidative modification product of LDL, in a clinical trial. This study aimed to identify the intracellular active component of ST-1 associated with anti-oxidative activity against LDL oxidation. High-performance liquid chromatography-electrospray ionisation mass spectrometry analysis after fractionation of the cellular extract by reversed-phase chromatography demonstrated that the active fraction contained reduced glutathione (GSH). GSH showed anti-oxidative activity in a dose-dependent manner, while this activity disappeared following thiol derivatisation. ST-1 had the strongest anti-oxidative activity against LDL oxidation and the highest level of intracellular GSH among five strains of S. thermophilus. In addition, the anti-oxidative activity of ST-1 after thiol derivatisation decreased by about half, which was similar to that of three other strains containing poor or no intracellular GSH or thiol components. Moreover, anti-oxidative activity against LDL oxidation was observed in hyperlipidaemic hamsters fed with high GSH ST-1 cells but not in those given low GSH cells. These findings suggest that intracellular GSH in ST-1 may provide beneficial effects via anti-oxidative activity against LDL oxidation and excess oxidative stress in the blood.


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