• BMB Reports
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• v.30 no.1
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• pp.1-6
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• 1997

The ability of Hep-G2 cells to process $[^{125}I]LDL$ under basal conditions was investigated. The receptor-binding and internalization of $[^{125}I]LDL$ increased with the time of incubation in a saturable manner. After 4 h of incubation, 31.4 ng of $[^{125}I]LDL$ was cell bound. The cells rapidly internalized $[^{125}I]LDL$ via specific, receptor-mediated endocytosis. The amount of internalized $[^{125}I]LDL$ reached a maximun of 96.7 ng at 2 h of incubation and remained constant for the next 2 h. The rate of degradation of internalized $[^{125}I]LDL$ proceeded in a linear manner over the entire 4 h of incubation after an initial lag period. The effects of individial fatty acids (C18:0. C18:1, C18:2. and C18:3), differing in their degree of unsaturation. on the receptor-binding, internalization and degradation of $[^{125}I]LDL$ were also investigated. Inclusion of 1.0 mM of each fatty acid into the culture medium significantly increased $[^{125}I]LDL$ metabolism in Hep-G2 cells. Among the fatty acids tested, stearic acid had the least effect on the receptor-binding activity. There were no significant differences among the unsaturated fatty acids in LDL-receptor binding. The effect of individual fatty acids on the $[^{125}I]LDL$ uptake was similar to that of the receptor-binding. showing a significantly lower effect with stearic acid. The amount of degraded material of internalized $[^{125}I]LDL$ was the lowest with stearic acid when it was compared with unsaturated fatty acids.

• Korean Journal of Clinical Laboratory Science
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• v.44 no.3
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• pp.103-111
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• 2012

Low-Density Lipoprotein cholesterol (LDLC) is the most important marker for the treatment of hyperlipidemia in NCEP-ATP III(National Cholesterol Education Program-Adult Treatment Panel III) guideline. Therefore, LDL cholesterol is pathologically meaningful, accurate measurement should be a top priority. Currently, LDLC is directly measured in most cases, but, the estimate is still used in mass health examination or screening test. This study is about the comparison of LDL-Cholesterol direct measurement with the estimate using various formula (Friedewald: [LDL-F=TC-HDL-TG/5], Nakajima: [LDL-N=TC-HDL-TG/4], Hattori: [LDL-H =0.94TC-0.94HDL-0.19TG], Puavilai: [LDL-P=TC-HDL-TG/6], Carvalho: [LDL-C=3(TC-HDL)/4]) for calculating more accurate value. We analyzed total cholesterol (TC), try-glyceride (TG), high-density lipoprotein cholesterol (HDLC), and LDLC levels of 210 subjects between June and November in 2011. Until now, the Friedewald formula is the most commonly used estimate for the LDLC. When Friedewald formula was applied, the correlation coefficient (r) was 0.940, showing high correlation. But, the result of the direct method was significantly different, compared with those of the Friedewald formula in triglyceride levels ${\geq}400mg/dL$(p<0.05). There was the highest correlation when we used LDL-P formula(r=0.947) in triglyceride levels <400 mg/dl. Also there was the lowest mean difference regardless of triglyceride level. Therefore, the study showed that TG/6 is more precise means of calculation than TG/5. On the other hand, the calculation of LDL-Cholesterol was underestimated, compared with direct measurement. It is necessary to have more data and modified Friedewald formula should be used for the accurate calculation.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.4
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• pp.486-494
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• 2006

In order to protect the spermatozoa against cold shock, hen egg yolk is widely used as a cryoprotective agent in semen freezing extenders for domestic animals. The protective action of yolk is largely presumed to be due to low density lipoproteins (LDL). The effects of LDL on sperm quality of bull and northern pike (Esox lucius) after freezing-thawing have been reported, but no study has been made to evaluate the effect of LDL on boar sperm motility and other characteristics. The experiment was carried out to investigate the effect of LDL on the freezing of boar sperm in 0.25 ml straws. The aim was to evaluate the quality of boar spermatozoa cryopreserved in the presence of LDL. Motility of semen cryopreserved in LDL was analyzed and compared to semen cryopreserved with Tris-citric acid-glucose (TCG) and Tris-citric acid-fructose (TCF), two basic freezing extenders containing egg yolk. Similarly, acrosome and plasma membrane integrity were also evaluated and compared to semen cryopreserved with TCG and TCF. Analysis of sperm quality after freeze-thaw showed that the motility, acrosome and plasma membrane integrity were improved with LDL in the extender, as compared to the TCG and TCF. The highest post-thaw integrity of acrosome and plasma membrane and motility were obtained with 9% LDL (w/v). Consequently, the optimum LDL concentration in the extender was 9%. It is also suggested that the concentration of LDL addition is important for the effect on boar sperm protection during freezing and thawing. The percentage of motile spermatozoa was significantly higher after freezing in 9% LDL than in TCG and TCF 54.4% versus 30.4% and 30.1% (p<0.05), respectively. The integrity of acrosome and plasma membrane were also significantly higher at 70.3% and 50.5% respectively with semen frozen in 9% LDL extender compared to TCG at 37.8% and 30.3% and TCF at 36.4% and 29.9%, respectively (p<0.05),. In conclusion, we propose that extender containing LDL extracted from hen egg yolk could be used as a cryoprotective media with a better efficiency than TCG and TCF. LDL improved boar semen quality, allowing better spermatozoa motility, acrosome and plasma membrane integrity after the freeze-thaw process. Furthermore, we found out that the extender with 9% LDL concentration significantly enhanced motility, acrosome and plasma membrane integrity of boar sperm after freezing and thawing.

• Journal of Embryo Transfer
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• v.27 no.3
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• pp.155-162
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• 2012

This study was designed to determine whether low-density lipoporoteins (LDL) extracted from egg yolk in extender improve the function of Korean Jeju Black Bull semen. The semen was cryopreserved with 5% ethylene glycol (EG) or 7% glycerol (G) extenders containing 10% egg yolk (EY), 4% LDL and 5% EY or 8% LDL. Frozen-thawed sperm were evaluated sperm motility, viability, membrane integrity and acrosome integrity. Post-thawed sperm motility has been significantly higher (p<0.05) in 4% LDL + 5% EY ($69.00%{\pm}4.18$; EG and $63.00%{\pm}9.75$; 7% G) than 8% LDL ($57.00%{\pm}5.70$; EG and $52.00%{\pm}4.47$;G). Treatment of 4% LDL + 5% EY-EG ($66.85%{\pm}5.06$) has been significantly improved sperm viability compared to other treatments except 10% EY - EG. Moreover, in membrane integrity, swollen sperm ratio has been only significantly increased (p<0.05) in 4% LDL + 5% EY - EG ($64.65%{\pm}6.10$) among all treatments. In assess to detect acrosome integrity, especially, AR pattern ratio has been significantly decreased (p<0.05) in 4% LDL + 5% EY - EG among all treatments. In sperm viability as time passes, between 4% LDL + 5% EY and 10% EY, there was no significant difference, but 8% LDL was significantly decreased sperm viability in EG (1 and 2 hrs) and G (30 min, 1, 2, 5 and 12 hrs) extender. However, there were no significant differences among all treatments except 8% LDL-G in sperm membrane integrity. 8% LDL-G has been significantly decreased swollen sperm ratio at 5 hrs after thawed. It is concluded from these results that 4% LDL + 5% EY to the freezing extender showed more positive effect on the frozen-thawed spermatozoa in Korean Jeju Black bull.

• Journal of Nutrition and Health
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• v.31 no.8
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• pp.1235-1243
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• 1998

Although an elevated plasma level of high density lipoprotein (HDL) is known as a protective component against the development of atherosclerosis and ensuing coronary heart diseases, the related mechanisms are still not established . It has been clearly demonstrated in the early stages of atherogenesis that adhesion of monocytes and lymphocytes to the vascular endothelium is enhanced via adhesion molecules, and that monocytes and macrophages accumulate in the subendothelial space. The present study has investigated whether isolated plasma HDL plays a role in protection against atherogenesis by inhibiting the expression of vascular cell adhesioin molecule-1(VCAM-1) on the endothelial cells. Effects of plasma native low density lipoprotein (LDL) and ac ethylated LDL(AcLDL) on VCAM-1 expression were also examined by using an immunocytochemical technique. While plasma HDL did not alter the basal expression of VCAM-1 , lipopolysaccharide(LPS) induction of this adhesion modlecule was markedly inhibited at a phyaiological concentration of HDL. In contrast, 30$\mu\textrm{g}$ protein/ml AcLDL increased sifnificantly both basal VCAM-1 expression and its LPD induction , suggesting that this modified LDL enhances leukocyte adhesiion to endothelial cells. Unlike AcLDL , plasma native LDL inhibited significantly VCAM-1 expression. This indicates that LDL did not undergo oxidative modificantion while incubated with endothelial cells. These results suggest that plasam HDL may inhibit atherogenesis by reducing the expression of adhesion molecules, which is a protective mechanism independent of tis reverse cholesterol transport function . Modified LDL is a potent iducer for adhesion molecules in vascular endothelical cells and could play a role in the pathogenesis of atherosclerosis by adhering to blood cells.

• Journal of Periodontal and Implant Science
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• v.50 no.3
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• pp.135-145
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• 2020

Purpose: The aim of this study was to evaluate the serum levels of oxidized low-density lipoprotein (oxLDL), anti-oxLDL, and myeloperoxidase (MPO) in hyperlipidemic patients with periodontal disease. Methods: This study included 123 patients with hyperlipidemia categorized based on metabolic control as mild to moderate (H1) (n=66) or poor (H2) (n=57), as well as systemically healthy controls (C) (n=68). Serum levels of lipids, oxLDL, anti-oxLDL, and MPO were evaluated, along with clinical periodontal parameters. Results: The percentage of bleeding on probing (BOP%) and the clinical attachment level were significantly higher in the H2 group than in the C group. Patients with hyperlipidemia had a relatively high risk of developing periodontal disease. The oxLDL and anti-oxLDL levels were higher in H2 patients with periodontitis than in the control or H1 patients with periodontitis. In the H1 and H2 groups, the ratio of total cholesterol to high-density lipoprotein was significantly correlated with gingival index, BOP%, and oxLDL levels. Conclusions: Our findings indicate that the lipoprotein-associated inflammatory mediators of oxLDL, anti-oxLDL, and MPO may play an important role in the relationship between periodontal disease and hyperlipidemia.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.12
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• pp.1899-1907
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• 2013

We investigated the effects of unripe black raspberry water extract (UBR-W) and oxidation-LDL treatment on cholesterol levels. Experiments using an established human hepatocellular carcinoma cell line (HepG2) showed a time-dependent increase in expression of LDL receptor after UBR-W treatment. Expression of LDL receptor-related genes, such as SREBP1 and 2, increased upon UBR-W treatment. However, expression of HDL-related genes was unaffected by UBR-W. HMG-CoA reductase activity was reduced by UBR-W treatment, whereas HMG-CoA mRNA expression significantly increased. In addition, the ApoB/ApoA1 mRNA level, which is a predictor of cardiovascular risk, was reduced in a time-dependent manner by UBR-W treatment. Macrophage-like cells (RAW 264.7) showed increased expression of ox-LDL-related genes, such as CD36, scavenger receptor-A, adipophilin, and PPAR-gamma, upon ox-LDL treatment compared to untreated control cells, and quantitative lipid analysis indicated a dramatic increase in lipid accumulation. However, UBR-W treatment significantly reduced expression of ox-LDL-related genes and largely prevented lipid accumulation. The results indicate that UBR-W mediates a cholesterol-lowering effect via inhibition of cholesterol synthesis and induction of LDL uptake through SREBP.

• Journal of Life Science
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• v.20 no.11
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• pp.1595-1602
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• 2010

Oxidation of low density lipoprotein (LDL) has been recognized as an important role in the initiation and progression of atherosclerosis. In this study, effects of allylmercaptan, a major metabolite compound of garlic, was studied on endothelial cell injury induced by oxidized low density lipoprotein (ox-LDL). The antioxidative activity of allylmercaptan was investigated by monitoring a thiobarbituric acid substance (TBARS). Allylmercaptan inhibited LDL oxidation induced by $Cu^{2+}$ at concentrations of 0.1, 1 and 10 mM in a dose dependent manner. Lactate dehydrogenase (LDH) release, as an index of cell injury, and intracellular glutathione levels were determined. Pulmonary artery endothelial cells were preincubated with allylmercaptan at $37^{\circ}C$ and 5% $CO_2$ for 24 hr, washed, and then exposed to 0.1 mg/ml oxidized LDL for 24 hr. Preincubation of endothelial cells with allylmercaptan significantly prevented the LDH release and depletion of GSH. Peroxides were measured directly in 24 well plates using a fluorometric assay. Allylmercaptan inhibited release of peroxides induced by ox-LDL in pulmonary artery endothelial cells. In a free system, allylmercaptan was shown to scavenge hydrogen peroxide. The data indicate that allylmercaptan can protect pulmonary artery endothelial cells from injury caused by oxidized LDL, and suggest that allylmercaptan may be useful for the prevention of atherosclerosis.

• Journal of Food Hygiene and Safety
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• v.13 no.1
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• pp.6-13
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• 1998

This study was carried out to investigate the antioxidative activity on oxidaton of human low density lipoprotein from marine microorganisms. Bacillus sp. RH-5 producing antioxidative activity have been isolated and identified from coast sea in Pusan. Bacillus sp. RH-5 produced at highest level of antioxidative activity in the medium of 1.0% glucose, 0.25% polypepton, 0.25% yeast extract, 0.01% $FeSO_4{\cdot}7H_2O$ and 50% sea water. The optimal medium pH, cultural temperature and shaking time for the highest production as the antioxidant were 7.0, $30^{\circ}C$ and 48 hr, respectively. The culture broth inhibited the copper catalyzed oxidation of human low density lipoprotein (LDL) at the concentration of 500 and $1,000\;\mu\textrm{g}/ml$ ethylacetate extracts in the presence of $5\;\mu\textrm{M}\;CuSo_4$. The electrophoretic mobility of the LDL oxidized in the presense of $5\;\mu\textrm{M}\;CuSo_4$ was higher than that of native LDL.

• Journal of Life Science
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• v.17 no.10
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• pp.1330-1335
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• 2007

This study was developed to assess the antioxidative activity of aged black garlic extract on lipid peroxidation and low density lipoprotein (LDL). Antioxidative activity of aged black garlic extract on human low density lipoprotein (LDL) was investigated by monitoring a barbituric acid reactive substance (TBARS). Electron donating ability (EDA) of aged black garlic, ethanol extract was higher than that alliin and water extract. Aged black garlic water and ethanol extracts inhibited the $Cu^{2+}$ mediated oxidation of human LDL in a dose dependent manner at concentration of 10 and $20\;{\mu}g/ml$. Ethanol extract and water extract of aged black garlic almost completely inhibited J774 mediated LDL oxidation in electrophoretic mobility and conjugated diene. These results indicate that aged black garlic might play a protective antioxidant effects on LDL, probably affecting the structural properties for the LDL oxidation.