Jun 22, 2011 - Jung Eun Kim,3 Jose O. Leite,3 Ryan deOgburn,3 Joan A. Smyth,4 ..... Jong PT, Nemesure B, Mitchell P, Kempen J. Prevalence of age-related.
The Journal of Nutrition Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions
A Lutein-Enriched Diet Prevents Cholesterol Accumulation and Decreases Oxidized LDL and Inflammatory Cytokines in the Aorta of Guinea Pigs1,2 Jung Eun Kim,3 Jose O. Leite,3 Ryan deOgburn,3 Joan A. Smyth,4 Richard M. Clark,3 and Maria Luz Fernandez3* 3
Department of Nutritional Sciences, and 4Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT 06269
Abstract Lutein has been shown to be protective against age-related macular degeneration; however, the antiinflammatory and antioxidant effects of this carotenoid in aortas are less known. Guinea pigs were fed a hypercholesterolemic diet (0.25 g cholesterol/100 g) and randomly allocated to a control group (n = 9) or a lutein group (n = 10) (0.1 g/100 g lutein) and fed the experimental diets for 12 wk. Plasma LDL cholesterol and TG did not differ between groups; however, the lutein group had lower concentrations of medium size LDL (P , 0.05). As expected, guinea pigs from the lutein group had higher concentrations of plasma and liver lutein than those from the control group (P , 0.0001). Aortic cholesterol and malondialdehyde concentrations were lower in the lutein group (9.6 6 2.8 mmol/g and 1.69 6 1.35 nmol/mg protein) compared to the control group (15.5 6 2.3 mmol/g and 2.98 6 1.45 nmol/mg protein) (P , 0.05). Hematoxilin and eosin staining indicated that aortas from the control group presented focal intimal thickening, whereas either less thickness or no visible thickness was present in aortas from the lutein group. Oxidized LDL (oxLDL) was lower both in plasma and aorta in the lutein group compared to the control group (P , 0.001). Aortic cytokines were also lower in the lutein group (P , 0.05). Plasma lutein and oxLDL (r = 20.79; P , 0.0001) and plasma lutein and aortic oxLDL (r = 20.64; P , 0.0001) were negatively correlated. These data suggest that lutein exerts potent antioxidant and antiinflammatory effects in aortic tissue that may protect against development of atherosclerosis in guinea pigs. J. Nutr. 141: 1458–1463, 2011.
Introduction Lutein, a carotenoid found primarily in green leafy vegetables and egg yolk, is preferentially located in the retina (1). Lutein is thought to have a role in protecting the retina against light damage (2); hence, there has been a major focus of research on age-related macular degeneration (AMD)5 (2,3). AMD is a leading cause of vision loss in the elderly (4) and the prevalence of AMD continues to grow in the United States (5). In addition to its protective effect against AMD, lutein is emphasized as a beneficial antioxidant due to its structural characteristics. Lutein contains conjugated C = C double bonds, which can readily quench singlet oxygen species (6). Previous studies have shown that lutein is useful in the prevention of systemic inflammation in response to LPS treatment in animal models (7,8) and in 1
Supported by a University of Connecticut Research Foundation grant to M.L.F. Author disclosures: J. E. Kim, J. O. Leite, R. DeOgburn, J. A. Smyth, R. M. Clark, and M. L. Fernandez, no conflicts of interest. 5 Abbreviations used: AMD, age-related macular degeneration; HDL-C, HDL cholesterol; LDL-C, LDL cholesterol; MDA, malondialdehyde; oxLDL, oxidized LDL. * To whom correspondence should be addressed. E-mail: maria-luz.fernandez@ uconn.edu. 2
1458
RAW264.7 cells (7,9) by inhibiting NF-kB–dependent signaling pathways and the subsequent production of proinflammatory mediators. In addition, lutein treatment also decreased intracellular reactive oxygen species accumulation in RAW264.7 cells (9), which suggests an antioxidant effect of lutein. Based on these properties, lutein may play a role in the prevention of atherosclerosis (10,11). One of the main features of atherosclerosis, the major cause of coronary heart disease, is the accumulation of lipids and fibrous elements in large arteries (12). The first step that initiates atherosclerosis is the presence of LDL in the subendothelial matrix and its subsequent oxidation. Oxidized LDL (oxLDL) in the vessel wall is a major contributor to foam cell formation (12,13). OxLDL stimulate the overlying endothelial cells to produce adhesion molecules, resulting in the recruitment of monocytes to the vessel wall (12,14). The recruited monocytes are differentiated into macrophages and macrophages release cytokines such as TNFa and IL-6 (12). We hypothesized that lutein would reduce inflammation and oxidation in plasma and aorta and would prevent early atherosclerosis development. Therefore, we evaluated the effects of this carotenoid on circulating atherogenic lipoproteins and oxLDL as well as on cytokine production. The present study
ã 2011 American Society for Nutrition. Manuscript received March 15, 2011. Initial review completed April 27, 2011. Revision accepted May 23, 2011. First published online June 22, 2011; doi:10.3945/jn.111.141630.
utilized guinea pigs as the animal model, because they present similar responses to dietary interventions and lipoprotein metabolism as humans (15). Guinea pigs were fed a hypercholesterolemic diet to develop early atherosclerosis and inflammatory responses in a short period of time (16).
Materials and Methods Animals. Nineteen male Hartley guinea pigs, aged 18 mo old (Charles River Breeding Laboratories), were randomly assigned to 2 groups, the lutein group and the control group. All guinea pigs were fed high cholesterol (0.25 g/100 g of diet) and the lutein group was treated with lutein (0.1 g/100 g of diet) (FloraGLO trans Lutein, Kemin Industries) for 12 wk. The composition of the experimental diets is presented in Table 1. The composition of the vitamin and mineral mix was previously reported (17). Animal protocols were approved by the Institutional Animal Care and Use Committee from the University of Connecticut. After 12 h of being feed deprived, guinea pigs were killed and blood, liver, and aorta were collected. Plasma and liver lutein concentration. Approximately 0.5 g of liver or 500 mL of plasma was prepared for carotenoid analysis by saponification and extraction with hexane and ethyl ether. Samples were prepared as previously reported (18). Plasma lipids. Photometric measurements were used to measure plasma lipids including total cholesterol, LDL cholesterol (LDL-C), HDL cholesterol, and TG (19) by using Cobas c 111 analyzer (Roche-Diagnostics). Before analyses, samples were mixed with aprotinin (0.5 mL/100 mL), sodium azide (0.1 mL/100 mL), and phenylmethylsulfonyl fluoride (0.1 mL/100 mL) to prevent degradation. Lipoprotein subfractions and size. NMR analysis was performed on a 400-MHz NMR analyzer (Bruker BioSpin) as previously described (20). Cholesterol accumulation in aorta and arterial morphology. Total cholesterol was measured in the abdominal aorta by extraction with chloroform:methanol (2:1) and then analyzed as described by Leite et al. (21). Aortas from each guinea pig were fixed in 10% neutral buffered formalin for histopathologic examination. Hematoxylin and eosinstained, formalin-fixed, paraffin-embedded sections of the aorta were examined for atherosclerosis by a certified pathologist who was unaware of the treatments. The method of Stary et al. (22) was used for the evaluation of atherosclerosis.
TABLE 1
Composition of experimental diets of guinea pigs from the control or lutein groups
Components
Soybean protein Carbohydrate1 Fat2 Vitamins3 Minerals3 Cellulose Guar gum Cholesterol Lutein4 1
Lutein g/100 g 22 41 15.1 1.1 8.2 10 2.5 0.25 0.1
Control % Energy 23 42 35 — — — — — —
g/100 g 22 41 15.1 1.1 8.2 10 2.5 0.25 —
% Energy 23 42 35 — — — — —
Corn starch:sucrose ratio, 1:1.43. Fat mix was olive oil-palm kernel oil-safflower oil (1:2:1.8), high in lauric and myristic acids. 3 Vitamin and mineral mixes were formulated to meet the NRC requirements for guinea pigs. A detailed composition of the vitamin and mineral mix has been reported elsewhere (17). 4 Lutein was provided by FloraGLO (Kemin Industries). 2
Aortic and plasma oxLDL. Aortic oxLDL concentrations were measured in homogenized descendent thoracic aorta. The vessel was dissected (0.05 g) and the surrounding tissues were removed as previously reported (23). Both aortic and plasma oxLDL were analyzed using a mouse competitive ELISA from Mercodia, which is based in the mouse monoclonal antibody 4E6, which is directed against a conformational epitope in oxidized ApoB-100.We have successfully used this method to measure oxLDL in guinea pigs (16). Aortic malondialdehyde concentrations. Aortic malondialdehyde (MDA) was measured by TBARS assay using a commercially available assay kit (Cayman Chemical). Samples (150 mL) and standards were read by fluorescence at an excitation wavelength of 530 nm and an emission wavelength of 550 nm. Detected MDA were normalized to aortic protein concentrations, which were measured using the Bradford assay (Bio-Rad Laboratories). Inflammatory cytokine concentration in the aorta. Cytokines were evaluated from homogenates of aorta, such as described elsewhere (21) using the MILLIPLEX MAP Mouse Cytokine PREMIXED Immunoassay kit (Millipore) and Luminex system (Luminex 200 System). The following aortic cytokines were measured: TNFa, IFNg, IL-1b, IL-2, IL-4, IL-5, IL-6, IL-7, IL-10, IL-12, and IL-13. Statistical analyses. Statistical analyses were performed by using SPSS 17.0. Values are reported as mean 6 SD. Independent t test and bivariate correlations were used when appropriate. Results with P , 0.05 were considered to be significant.
Results Plasma lipids. Plasma total cholesterol concentrations did not differ between the lutein group (4.45 6 1.50 mmol/L) and control group (3.78 6 1.06 mmol/L), nor did LDL-C or TG, which were 3.38 6 1.0 mmol/L and 3.06 6 1.10 mmol/L, and 0.90 6 0.17 mmol/L and 0.76 6 0.27 mmol/L, respectively. Plasma and hepatic lutein concentration. Plasma lutein concentrations of guinea pigs from the lutein group were higher compared to the control group (P , 0.0001) (Table 2). Hepatic lutein concentrations in the lutein group (23.8 6 5.6 nmol/g) were also higher than in the control group (, 1 nmol/g) (P , 0.0001). Plasma LDL particle size and concentration. LDL particle size and LDL subfraction concentrations did not differ between groups (data not shown). The percent distribution of large and small LDL particles also did not differ between the groups, whereas the percent distribution of medium LDL particles was lower in the lutein group (19.2 6 3.0%) compared to the control group (26.1 6 8.5%) (P , 0.05). TABLE 2
Plasma and liver lutein and aorta total cholesterol and malondialdehyde (MDA) concentrations of guinea pigs fed lutein or control diets for 12 wk
Variables Plasma lutein, nmol/L Liver lutein, nmol/g Aorta Cholesterol, mmol/g MDA, nmol/mg protein 1
Lutein (n = 10)
Control (n = 9)
P-value
75.1 6 17.1 23.8 6 5.6
,5 ,1
,0.0001 ,0.0001
9.6 6 2.8 1.69 6 1.35
15.5 6 2.3 2.98 6 1.45
,0.0001 ,0.05
Values are mean 6 SD.
Lutein and antioxidant and antiinflamamtory properties
1459
FIGURE 1 Concentrations of oxLDL in plasma (A) and aorta (B) of guinea pigs fed a control or lutein diet for 12 wk. Values are mean 6 SD, n = 9 (control) or 10 (lutein) *Different from control, P , 0.01.
Aortic total cholesterol and MDA concentration. Aorta total cholesterol concentrations were lower for the lutein group compared to the control group (P , 0.001) (Table 2). In addition, the lutein group also had lower aortic MDA concentrations than the control group (P , 0.05), indicating attenuated lipid peroxidation in the lutein group (Table 2). OxLDL concentrations in plasma and aorta. Plasma oxLDL concentrations in the lutein group were lower than in the control group (P , 0.0001) (Fig. 1A). Similarly, aortic oxLDL concentration in the lutein group was also lower compared to the control group (P , 0.001) (Fig. 1B). Correlations between lutein concentrations and aortic cholesterol and plasma and aortic oxLDL. Plasma (r = 20.79; P , 0.001) and hepatic (r = 20.73; P = 0.001) lutein concentrations were negatively correlated with aortic total cholesterol. In addition, plasma and aortic oxLDL and aortic total cholesterol were negatively correlated with plasma oxLDL (r = 20.79, P , 0.001; r = 20.72, P = 0.001) and aortic oxLDL (r = 20.64, P , 0.01; r = 20.69, P , 0.001), indicating associations between lutein concentrations and oxLDL production. Cytokine concentration in aorta. Guinea pigs from the lutein group had significantly lower concentrations of most of the inflammatory cytokines, including IFNg, TNFa, IL-1b, IL-2, IL-4, IL-5, IL-6, IL-7, IL-10, and IL-12 than guinea pigs from the control group (Fig. 2). The aorta IL-13 concentration did not differ between the groups. Aortic morphology. For aortic morphology, 6 guinea pigs/ group were examined. Two guinea pigs in the control group (33%) had focal intimal thickening due to the presence of layers of myointimal cells (Fig. 3A). Lipid vacuoles were present in some of these cells and in the extracellular matrix. These changes are features of atherosclerosis. Among the remaining guinea pigs, there was variation in the thickness of the proteoglycan matrix in the intima and rare macrophages, some of which contained lipid vacuoles (foam cells). In addition and with only one exception, the thickness of the proteoglycan layer was less in the lutein group and was not visible in 2 of the lutein-treated animals (Fig. 3B). Thus, 84% of the examined guinea pigs from the lutein group presented no thickness of the proteoglycan layer, whereas 100% of the control group presented either features of early atherosclerosis or increased thickness in the proteoglycan matrix in addition to macrophages and foam cells. 1460
Kim et al.
Discussion In this study, we demonstrated that in guinea pigs, dietary lutein was beneficial in preventing early atherosclerosis development by lowering circulating atherogenic lipoproteins and oxLDL as well as decreasing MDA and cytokine production in aortas without changing plasma lipid profiles. Further hematoxylin and eosin staining indicated that aortas from the control guinea pigs presented thickened intima plaque with the presence of foam cells, which was not present in the majority of guinea pigs from the lutein group. Because the absorption of carotenoids varies widely depending on the food matrix (6) and we were uncertain of the rate of lutein absorption in guinea pigs, we provided the equivalent of 25–30 mg lutein/d, which is higher than supplement intake in humans (6–10 mg/d) (24,25). Based on the results from this study, guinea pigs have slightly lower concentrations of plasma lutein compared to humans (6,18), suggesting that the provided amount of dietary lutein was adequate to ensure sufficient circulating levels of this carotenoid to determine its antioxidant and antiinflammatory effects in the aorta. Lutein, lipoproteins, oxLDL, and aortic cholesterol. Lutein had no effect on plasma lipid profiles as expected. Similar to our findings, no significant change in plasma LDL-C concentration was observed in ApoE null mice with lutein treatment (0.2 g/100 g)
FIGURE 2 Concentrations of cytokines in aorta of guinea pigs fed a control or lutein diet for 12 wk. Values are mean 6 SD, n = 9 (control) or 10 (lutein). Asterisks indicate different from control, *P , 0.05, **P , 0.01.
FIGURE 3 Features of aortas of guinea pigs fed a control or lutein diet for 12 wk. Aortas from 6 pigs/group were stained with H and E. Two of the guinea pigs (33%) from the control group presented features characteristic of early atherosclerosis development (A). Arrowheads indicate lipid vacuolation and arrows indicate internal elastic lamina. The rest of the control group (66%) plus one guinea pig from the lutein-treated group (17%) presented a thick proteoglycan layer and presence of some vacuoles and macrophages that indicate potential development of atherosclerosis. Guinea pigs from the lutein group (84%) presented no proteoglycan layer (B).
(10). However, we observed that the percent distribution of plasma medium LDL particles was lower in the lutein group. Smaller LDL are more atherogenic than large LDL particles because of a decreased binding activity to the LDL receptor, leading to increased plasma residence time (26) and increased susceptibility to oxidation (27). Cardiovascular disease has been related to LDL particle size (28,29) and a higher number of circulating medium LDL particles is associated with increased risk for cardiovascular disease (30). An important initiating event in atherosclerosis development is the retention of LDL and other ApoB-containing lipoproteins in the subendothelial matrix (12). Small LDL has a greater possibility of being transported into the subendothelial space (31) and enters faster into the vessel wall than large LDL (19). We have previously shown in humans that there is less formation of small LDL with increases of dietary lutein, possibly to accommodate the higher concentrations of this carotenoid in plasma (32). It is possible that in guinea pigs, the higher concentrations of lutein in the secreted VLDL would result in the formation of a lower number of small LDL particles to allow for the transport of the higher lutein concentrations. Along with a significantly lower percent of smaller LDL particles in circulation, there was a 38% lower accumulation of total cholesterol in aorta of guinea pigs treated with lutein compared to the control guinea pigs. In regards to atherosclerosis development, only 2 guinea pigs in the control group developed classical atherosclerotic lesions. Although a subepithelial layer of proteoglycan matrix on its own is insufficient to qualify as atherosclerosis, it is nonetheless interesting that this layer was generally thinner or nonexistent in the lutein group. It is possible that if the guinea pigs had been maintained on the high-cholesterol diet for a longer period of time, other histological features of atherosclerosis may have
developed in the control group. Consistent with our findings, both ApoE null mice and LDL receptor null mice had smaller atherosclerotic lesions of the aortic arch in the lutein-supplemented condition relative to the control (10). Oxidative modification of LDL in the vascular endothelium is considered a pivotal factor in the development of early atherosclerosis (33). OxLDL promotes atherosclerosis through different mechanisms: by increases in the expression of adhesion molecules, enhancing migration of macrophages and smooth muscle cells, and augmenting the release of cytokines (34). OxLDL is also removed by macrophages, leading to the formation of foam cells, the first step in the initiation of atherosclerosis (12,35). Furthermore, oxLDL also causes oxidative stress in endothelial cells, smooth muscle cells, and macrophages and substantially contributes to the formation of the atherosclerotic plaque (35). It has also been suggested that circulating oxLDL is a marker of the early stage of atherosclerosis (36). In our findings, lutein treatment showed antioxidant effects by significantly lowering oxLDL both in plasma and aorta. Indeed, plasma and hepatic lutein concentrations were highly correlated with plasma and aortic oxLDL. Along with lower oxLDL concentrations, the lutein group also presented significantly lower aortic MDA, further supporting the role of lutein as an antioxidant. LDL-conjugated dienes have been used as a measurement of LDL oxidation (37,38). One study reported that plasma lutein concentration is a powerful antioxidant that determines serum LDL-conjugated dienes and reduces concentrations of oxLDL in circulation (38). Other studies support an antioxidant effect of lutein on LDL oxidation. When 100 nmol/L of lutein was added to endothelial and smooth muscle cells in human aortas, monocyte chemotactic activity induced by LDL oxidation was markedly reduced (10). Indeed, with in vitro experiments of human LDL, lutein has been shown to work as a scavenger of peroxynitrite radicals, which is the product of the reaction between NO and superoxide (39). However, the inhibition of LDL oxidation with lutein has not been observed in all studies (40). The discrepancies in results can be due to the methods that have been used to quantify oxLDL (10,39–41). The utilization of an antibody to oxLDL such as we used in the present study appears to give more accurate results (16). Lutein and inflammation. Inflammation is recognized as a major contributor to atherosclerosis through adverse effects on lipoprotein metabolism and arterial wall biology (42). OxLDL triggers the recruitment of monocytes and T-cells from circulation to the vessel wall by stimulating the production of adhesion molecules, chemotactic proteins, and growth factors, followed by monocyte proliferation and differentiation into macrophages (12,14), and finally production of inflammatory cytokines. In general, reduction in inflammatory aortic cytokines indicates a lower degree of arterial wall inflammation. Along with the reduced production of aortic oxLDL, guinea pigs fed with lutein produced lower levels of most inflammatory cytokines in aorta compared to the control group. An antiinflammatory effect of lutein as well as suppression of LPS-induced secretion of TNFa and IL-1b proteins and mRNA levels in primary cultured mouse peritoneal macrophages has been reported (9). It has also been shown that lutein directly decreases NF-kB activation and NF-kB promoter activity, which is involved in cytokine production (12). In addition, it has been demonstrated that lutein blocked the degradation of inhibitory kB-a from the cytosolic fraction and prevented NF-kB translocation (7). Therefore, another possible antiinflammatory mechanism of lutein is that this carotenoid suppresses NF-kB signaling pathways along with Lutein and antioxidant and antiinflamamtory properties
1461
subsequent proinflammatory cytokine gene expression. The lutein group also had lower concentrations of IL-10 in the present study. IL-10, a pleiotropic cytokine produced by a variety of immune cells, can inhibit inflammatory responses and it is thought to be an atheroprotective cytokine (43). However, IL-10 is a modulator of IL-12 action (44) and the lutein group also had reduced IL-12 levels, suggesting that lower levels of IL-10 were required to modulate the inflammatory process. Similar results have been reported in guinea pigs in a study using A-002 (Varespladib), a phospholipase A2 inhibitor (21). In summary, our findings suggest that lutein might contribute to the prevention of early atherosclerosis development by reducing cholesterol accumulation and features of atherosclerosis in aorta. Further, lutein might attenuate the inflammatory state in aorta by decreasing MDA and oxLDL levels and reducing inflammatory cytokines. Acknowledgments J.E.K. conducted the study, wrote the manuscript, and analyzed the data; J.O.L. and R.D. helped with laboratory assays and provided input in the writing of the manuscript; J.A.S. provided the evaluation of aortic morphology and took the pictures; R.M.C. analyzed hepatic and plasma lutein and provided input in data analysis and interpretation; and M.L.F. designed the experiment and analyzed and interpreted the data. All authors read and approved the final manuscript.
Literature Cited 1. 2. 3. 4.
5.
6. 7.
8.
9.
10.
11.
12. 13.
Bone RA, Landrum JT, Tarsis SL. Preliminary identification of the human macular pigment. Vision Res. 1985;25:1531–5. Landrum JT, Bone RA. Lutein, zeaxanthin, and the macular pigment. Arch Biochem Biophys. 2001;385:28–40. Krinsky NI, Landrum JT, Bone RA. Biologic mechanisms of the protective role of lutein and zeaxanthin in the eye. Annu Rev Nutr. 2003;23:171–201. Klaver CC, Wolfs RC, Vingerling JR, Hofman A, de Jong PT. Agespecific prevalence and causes of blindness and visual impairment in an older population: the Rotterdam Study. Arch Ophthalmol. 1998;116: 653–8. Friedman DS, O’Colmain BJ, Munoz B, Tomany SC, McCarty C, de Jong PT, Nemesure B, Mitchell P, Kempen J. Prevalence of age-related macular degeneration in the United States. Arch Ophthalmol. 2004; 122:564–72. Ribaya-Mercado JD, Blumberg JB. Lutein and zeaxanthin and their potential roles in disease prevention. J Am Coll Nutr. 2004;23:S567–87. Jin XH, Ohgami K, Shiratori K, Suzuki Y, Hirano T, Koyama Y, Yoshida K, Ilieva I, Iseki K, et al. Inhibitory effects of lutein on endotoxininduced uveitis in Lewis rats. Invest Ophthalmol Vis Sci. 2006;47:2562–8. Koutsos EA, Garcia Lopez JC, Klasing KC. Carotenoids from in ovo or dietary sources blunt systemic indices of the inflammatory response in growing chicks (Gallus gallus domesticus). J Nutr. 2006;136:1027–31. Kim JH, Na HJ, Kim CK, Kim JY, Ha KS, Lee H, Chung HT, Kwon HJ, Kwon YG, et al. The non-provitamin A carotenoid, lutein, inhibits NFkappaB-dependent gene expression through redox-based regulation of the phosphatidylinositol 3-kinase/PTEN/Akt and NF-kappaB-inducing kinase pathways: role of H(2)O(2) in NF-kappaB activation. Free Radic Biol Med. 2008;45:885–96. Dwyer JH, Navab M, Dwyer KM, Hassan K, Sun P, Shircore A, HamaLevy S, Hough G, Wang X, et al. Oxygenated carotenoid lutein and progression of early atherosclerosis: the Los Angeles Atherosclerosis Study. Circulation. 2001;103:2922–7. Dwyer JH, Paul-Labrador MJ, Fan J, Shircore AM, Merz CN, Dwyer KM. Progression of carotid intima-media thickness and plasma antioxidants: the Los Angeles Atherosclerosis Study. Arterioscler Thromb Vasc Biol. 2004;24:313–9. Lusis AJ. Atherosclerosis. Nature. 2000;407:233–41. Goldstein JL, Ho YK, Basu SK, Brown MS. Binding site on macrophages that mediates uptake and degradation of acetylated low density
1462
Kim et al.
14. 15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29. 30.
31. 32.
33.
lipoprotein, producing massive cholesterol deposition. Proc Natl Acad Sci USA. 1979;76:333–7. Mertens A, Holvoet P. Oxidized LDL and HDL: antagonists in atherothrombosis. FASEB J. 2001;15:2073–84. Fernandez ML, Volek JS. Guinea pigs: a suitable animal model to study lipoprotein metabolism, atherosclerosis and inflammation. Nutr Metab (Lond). 2006;3:17. Leite JO, DeOgburn R, Ratliff J, Su R, Smyth JA, Volek JS, McGrane MM, Dardik A, Fernandez ML. Low-carbohydrate diets reduce lipid accumulation and arterial inflammation in guinea pigs fed a highcholesterol diet. Atherosclerosis. 2010;209:442–8. Fernandez ML, McNamara DJ. Regulation of cholesterol and lipoprotein metabolism in guinea pigs mediated by dietary fat quality and quantity. J Nutr. 1991;121:934–43. Clark RM, Herron KL, Waters D, Fernandez ML. Hypo- and hyperresponse to egg cholesterol predicts plasma lutein and betacarotene concentrations in men and women. J Nutr. 2006;136:601–7. Nordestgaard BG, Zilversmit DB. Comparison of arterial intimal clearances of LDL from diabetic and nondiabetic cholesterol-fed rabbits. Differences in intimal clearance explained by size differences. Arteriosclerosis. 1989;9:176–83. Torres-Gonzalez M, Leite JO, Volek JS, Contois JH, Fernandez ML. Carbohydrate restriction and dietary cholesterol distinctly affect plasma lipids and lipoprotein subfractions in adult guinea pigs. J Nutr Biochem. 2008;19:856–63. Leite JO, Vaishnav U, Puglisi M, Fraser H, Trias J, Fernandez ML. A-002 (Varespladib), a phospholipase A2 inhibitor, reduces atherosclerosis in guinea pigs. BMC Cardiovasc Disord. 2009;9:7. Stary HC, Chandler AB, Glagov S, Guyton JR, Insull W Jr, Rosenfeld ME, Schaffer SA, Schwartz CJ, Wagner WD, et al. A definition of initial, fatty streak, and intermediate lesions of atherosclerosis. A report from the Committee on Vascular Lesions of the Council on Arteriosclerosis, American Heart Association. Circulation. 1994;89:2462–78. Sharman MJ, Fernandez ML, Zern TL, Torres-Gonzalez M, Kraemer WJ, Volek JS. Replacing dietary carbohydrate with protein and fat decreases the concentrations of small LDL and the inflammatory response induced by atherogenic diets in the guinea pig. J Nutr Biochem. 2008;19:732–8. Richer S, Stiles W, Statkute L, Pulido J, Frankowski J, Rudy D, Pei K, Tsipursky M, Nyland J. Double-masked, placebo-controlled, randomized trial of lutein and antioxidant supplementation in the intervention of atrophic age-related macular degeneration: the Veterans LAST study (Lutein Antioxidant Supplementation Trial). Optometry. 2004;75: 216–30. Seddon JM, Ajani UA, Sperduto RD, Hiller R, Blair N, Burton TC, Farber MD, Gragoudas ES, Haller J, et al. Dietary carotenoids, vitamins A, C, and E, and advanced age-related macular degeneration. Eye Disease Case-Control Study Group. JAMA. 1994;272:1413–20. Nigon F, Lesnik P, Rouis M, Chapman MJ. Discrete subspecies of human low density lipoproteins are heterogeneous in their interaction with the cellular LDL receptor. J Lipid Res. 1991;32:1741–53. Howard BV, Robbins DC, Sievers ML, Lee ET, Rhoades D, Devereux RB, Cowan LD, Gray RS, Welty TK, et al. LDL cholesterol as a strong predictor of coronary heart disease in diabetic individuals with insulin resistance and low LDL: The Strong Heart Study. Arterioscler Thromb Vasc Biol. 2000;20:830–5. Austin MA, King MC, Vranizan KM, Krauss RM. Atherogenic lipoprotein phenotype. A proposed genetic marker for coronary heart disease risk. Circulation. 1990;82:495–506. Schaefer EJ. Lipoproteins, nutrition, and heart disease. Am J Clin Nutr. 2002;75:191–212. Musunuru K, Orho-Melander M, Caulfield MP, Li S, Salameh WA, Reitz RE, Berglund G, Hedblad B, Engstrom G, et al. Ion mobility analysis of lipoprotein subfractions identifies three independent axes of cardiovascular risk. Arterioscler Thromb Vasc Biol. 2009;29:1975–80. Berneis KK, Krauss RM. Metabolic origins and clinical significance of LDL heterogeneity. J Lipid Res. 2002;43:1363–79. Greene CM, Waters D, Clark RM, Contois JH, Fernandez ML. Plasma LDL and HDL characteristics and carotenoid content are positively influenced by egg consumption in an elderly population. Nutr Metab (Lond). 2006;3:6. Steinberg D. The LDL modification hypothesis of atherogenesis: an update. J Lipid Res. 2009;50 Suppl:S376–81.
34. Yui S, Sasaki T, Miyazaki A, Horiuchi S, Yamazaki M. Induction of murine macrophage growth by modified LDLs. Arterioscler Thromb. 1993;13:331–7. 35. Ishigaki Y, Katagiri H, Gao J, Yamada T, Imai J, Uno K, Hasegawa Y, Kaneko K, Ogihara T, et al. Impact of plasma oxidized low-density lipoprotein removal on atherosclerosis. Circulation. 2008;118:75–83. 36. Ishigaki Y, Oka Y, Katagiri H. Circulating oxidized LDL: a biomarker and a pathogenic factor. Curr Opin Lipidol. 2009;20:363–9. 37. Ahotupa M, Asankari TJ. Baseline diene conjugation in LDL lipids: an indicator of circulating oxidized LDL. Free Radic Biol Med. 1999;27:1141–50. 38. Karppi J, Nurmi T, Kurl S, Rissanen TH, Nyyssonen K. Lycopene, lutein and beta-carotene as determinants of LDL conjugated dienes in serum. Atherosclerosis. 2010;209:565–72. 39. Panasenko OM, Sharov VS, Briviba K, Sies H. Interaction of peroxynitrite with carotenoids in human low density lipoproteins. Arch Biochem Biophys. 2000;373:302–5.
40. Milde J, Elstner EF, Grassmann J. Synergistic effects of phenolics and carotenoids on human low-density lipoprotein oxidation. Mol Nutr Food Res. 2007;51:956–61. 41. Hininger IA, Meyer-Wenger A, Moser U, Wright A, Southon S, Thurnham D, Chopra M, Van Den Berg H, Olmedilla B, et al. No significant effects of lutein, lycopene or beta-carotene supplementation on biological markers of oxidative stress and LDL oxidizability in healthy adult subjects. J Am Coll Nutr. 2001;20:232–8. 42. Hansson GK, Libby P. The immune response in atherosclerosis: a double-edged sword. Nat Rev Immunol. 2006;6:508–19. 43. Kleemann R, Zadelaar S, Kooistra T. Cytokines and atherosclerosis: a comprehensive review of studies in mice. Cardiovasc Res. 2008;79: 360–76. 44. Uyemura K, Demer LL, Castle SC, Jullien D, Berliner JA, Gately MK, Warrier RR, Pham N, Fogelman AM, et al. Cross-regulatory roles of interleukin (IL)-12 and IL-10 in atherosclerosis. J Clin Invest. 1996; 97:2130–8.
Lutein and antioxidant and antiinflamamtory properties
1463
