- Email: [email protected]
4P-0950 Baseline diet glycemic load and glycemic index are determinants of HDL cholesterol levels in patients with coronary heart disease: results from the LIPID study
282
Thursday October 2, 2003: Poster Session Nutrition
wines. Many studies have inducted that anthocyanins intake is associated with a low risk of cardiovascular disease. The aim of this work was to verify the hypothesis that cyanidin-3-glucoside (Cy-3-G), a typical anthocyanin pigment, induces discharge of nitric oxide (NO) and expression of the endothelial nitric oxide synthase (eNOS) in vascular endothelial cells. Methods: Bovine aortic endothelial cells (BAECs) were used for all experiments. BAECs were treated with Cy-3-G at various concentrations in serum-free Dulbecco’s modified Eagle’s medium. The western blot analysis of eNOS, Src kinase, ERK1/2 MAP kinase, and SP1 was made. The dominant negative Src cDNA in pUSEamp was transfected into BAECs according to the manufacturer’s instructions. Results: Cy-3-G induced eNOS expression in BAECs in time- and concentration-dependent manner. Cy-3-G also stimulated phosphorylation of Src kinase, ERK1/2 MAP kinase, and SP1 in time-dependent manner. Moreover, Src kinase inhibitor pp2 and MEK inhibitor PD98059 blocked eNOS expression and phosphorylation of Src kinase, ERK1/2 MAP kinase, and SP1. However, ICI-182780, an antagonist of estrogen receptor, could not inhibit the Cy-3-G-caused eNOS expression. BAPTA-AM, an intracellular calcium chelate, could also not restrain eNOS expression. In addition, the dominantnegative Src cDNA transfection blocked similarly the Cy-3-G-caused eNOS expression in BAECs. Conclusion: Our data showed that Cy-3-G induces eNOS expression via an Src-ERK1/2 MAP kinas pathway, and the increase of eNOS expression can explains the beneficial effect of anthocyanins at vascular level. 4P-0947
Beneficial effects of flavonoid supplement on blood glucose and antioxidant activities in type 2 diabetic mouse
U.J. Jung 1 , M.-K. Lee 1 , S.-J. Lee 2 , M.-S. Choi 1 . 1 Kyungpook National University; 2 Taegu Catholic University, Republic of Korea Objective: Oxidative stress is an early state in the diabetes mellitus pathology and may contribute to the development of complications. This study investigated the blood glucose-lowering effect and antioxidant capacity of three flavonoids on type 2 diabetes. Methods: Male C57BL/KsJ-db/db mouse (5 weeks old), type 2 diabetic animal model, were adjusted for 2 weeks with lab. chow diet, and fed a normal diet supplemented with or without naringin(0.02%, wt/wt), hesperidin(0.02%, wt/wt), or quercetin(0.02%, wt/wt) for 5 weeks. Results: The naringin, hesperidin, and quercetin supplements significantly lowered the levels of fasting blood glucose and hemoglobin A1c compared to those of the control. The plasma triglyceride and total-cholesterol concentrations were significantly lowered in three flavonoid supplemented groups. The naringin supplement significantly lowered the levels of plasma fatty acid. The overall potential for antioxidant protection was also significantly enhanced by naringin, hesperidin, and quercetin supplements. The activity of plasma and hepatic paraoxonase, enzyme that is responsible for preventing the lipid peroxides accumulation on LDL, was dramatically increased in these flavonoid supplemented groups. Three flavonoid supplements significantly increased the activities of antioxidant enzyme in erythrocyte, liver and kidney. In addition, the hesperidin supplement dramatically lowered the levels of TBARS in erythrocyte, liver and kidney, and naringin and quercetin supplements significantly lowered the levels of TBARS in erythrocyte and liver compared to those of control group. Conclusion: These results suggest that flavonoids used may play important roles in regulation of blood glucose and lipids and be useful for reducing oxidative stress in type 2 diabetic mouse. Nature of antidiabetic and antioxidative effect of these functional flavonoids needs to be elucidated. 4P-0948
Effects of cholesterol and naringin supplementation on cholesterol and hepatic antioxidant enzyme activities in LDL receptor-knockout mice
H.-J. Kim 1 , G.T. Oh 2 , T.-S. Jeong 2 , Y.B. Park 1 , M.-S. Choi 1 . 1 Kyungpook National University; 2 Korea Research Institute of Bioscience and Biotechnology, Republic of Korea Objective: To investigate the effects of naringin on lipid metabolism and hepatic antioxidant enzyme activities using LDLR-knockout mice. Methods: Mice that are homozygous for a targeted distruption of the LDL receptor gene (LDLR-/- mice) were used as a model of familial hypercholesterolemia. Male LDLR-knockout mice were fed a high-cholesterol (0.1 g/100 g) or high-cholesterol diet supplemented with naringin or lovastatin (0.02 g/100 g) for 6 weeks. Results: Supplementation of naringin and lovastatin significantly lowered
levels of plasma total cholesterol compared to the control group. The plasma and hepatic triglyceride level was only lowered by the lovastatin supplement, while the hepatic cholesterol content was lowered by both the naringin and lovastatin supplements compared to the control group. The hepatic HMGCoA reductase activity was significantly lower in the naringin and lovastatin supplemented groups than in the control group, whereas the ACAT activity was unaffected. Fecal excretion of neutral and acidic sterol were significantly increased by supplementation of lovastatin and naringin, respectively. The levels of hepatic TBARS were decreased by lovastatin supplementation, however naringin supplementation only showed a tendency to decrease hepatic TBARS. In comparisons of hepatic antioxidant enzyme activities, naringin supplementation significantly increased the hepatic superoxide dismutase, catalase and glutathion reductase activities compared to the control group, whereas lovastatin supplementation only increased glutathione reductase activity. However, glutathione peroxidase and glucose-6-phosphatedehydrogenase activities were not different between groups. Conclusion: Naringin supplementation lowered plasma cholesterol level via inhibition of hepatic HMG-CoA reductase and increase of fecal acidic sterol in cholesterol fed LDLR-knockout mice. 4P-0949
Influence of argan oil administration on lipid peroxidation and paraoxonase activities in healthy Moroccan men
M. Cherki 1 , A. Drissi 1 , A. Derouiche 1 , M. El Messal 2 , Y. Bamou 3 , A. Idrissi-Oudghiri 3 , A. Khalil 4 , A. Adlouni 1 . 1 Lab. de Recherche sur les Lipoprotéines, Fac. des Sciences Ben M’sik, Casablanca; 2 Lab. de Biochimie, Fac. des Sciences Aïn Chock, Casablanca; 3 Hôpital Militaire Moulay Ismail, Meknes, Morocco; 4 Lab. de Recherche sur l’athérosclérose et système immunitaire, Centre de Recherche sur le Vieillissement, IUGS, Canada Objective: To determine whether the consumption of virgin argan oil (VAO) could improve plasma lipids, paraoxonase (PON1) activities and LDL peroxidation in healthy Moroccan men. Methods: Sixty normolipidaemic adults were included in this interventional study. All subjects received 25 g/day of butter during 2 weeks as baseline. The group was randomized in 2 different diet periods of 3 weeks each one. The VAO group received 25 ml/day of oil and the extra virgin olive oil (EVO) group received the same quantity of olive oil as control group. At the end of each diet period, plasma lipids, PON1 activities and lipoperoxides were measured. Susceptibility of plasma isolated LDL oxidation was also analyzed. Results: Analysis of plasma lipids showed a significant increase of HDLcholesterol concentration in VAO (6.3%) and EVO (17.3%) groups (p=0.026, p= 0.001, respectively) and a significant decrease (13.8%) of LDL-cholesterol concentration only in EVO group (p=0.037) compared to baseline values. However, plasma triglycerides concentration significantly decreased (17.5%, p= 0.039) in only VAO group. Plasma PON1 activities increased significantly in both groups (p=0.003), however Hydroperoxides decrease significantly in VAO and EVO groups (p= 0.001, p=0.014 respectively). Susceptibility of LDL peroxidation show a significant increase of lag phase and a significant decrease of maximum dienes production in VAO (p=0.005) and in EVO groups (p=0.041, p=0.005 respectively). Conclusion: This study shows for the first time that the consumption of argan oil protects against atherosclerosis process by improving paraoxonase activities, lipid and antioxidant status. 4P-0950
Baseline diet glycemic load and glycemic index are determinants of HDL cholesterol levels in patients with coronary heart disease: results from the LIPID study
K. Mehalski 1 , J. Brand-Miller 1 , S. Blakesmith 1 , A. Kirby 1 , C. Pollicino 1 , K. Baghurst 2 , S. Record 2 , W. Hague 1 , J. Simes 1 , P. Nestel 3 , A. Tonkin 4 , D. Colquhoun 5 . 1 NHMRC Clinical Trials Centre, University of Sydney; 2 CSIRO; 3 Baker Research Institute; 4 National Heart Foundation; 5 Wesley Medical Centre, Australia Objective: To assess the extent to which dietary carbohydrate, expressed as glycemic index (GI) and glycemic load (GL) affects lipids and lipoproteins in patients with coronary heart disease (CHD). Background and Rationale: The glycemic load of the diet influences lipoprotein levels and the risk of CHD in asymptomatic individuals. The effects of GI and GL in patients with CHD taking standard drug therapy are unknown. Methods: LIPID was a placebo-controlled double-blind trial that assessed the efficacy of pravastatin over 6 years in 9014 patients with CHD and baseline cholesterol 4–7 mmol/L. In a diet sub study, 1077 patients completed
XIIIth International Symposium on Atherosclerosis, September 28–October 2, 2003, Kyoto, Japan
Thursday October 2, 2003: Poster Session Atherogenic lipoproteins and their receptors a validated food-frequency questionnaire of more than 170 foods during the trial’s run-in period. Carbohydrate foods were allocated a GI value, and GL of the diet was calculated by multiplying the carbohydrate value of each food by its GI, then multiplying this by the frequency of consumption, and finally summing the values from all carbohydrate foods in the diet. Results: Serum HDL cholesterol was inversely correlated with both GI (r = -0.140, P<0.001) and GL (r = -0.122, P<0.001). This relationship was noted when factors were analysed as continuous variables, and when GI and GL were divided by quartile (graph). Pravastatin therapy did not affect this relationship.
Conclusion: GI and GL significantly influence HDL cholesterol, a major determinant of prognosis in these patients with CHD. Diets with low GI and GL may improve CHD outcomes. 4P-0951
Recommended fish intake is potentially dangerous due to high methylmercury content of certain fish
enhanced under oxidative stress). We thus questioned whether this is related to the ability of PON 1 to protect against lipids peroxidation in lipoproteins and in arterial cells. Results: PON1 hydrolyzed cholesteryl linoleate hydroperoxides (CL-OOH) in oxidized LDL, HDL and macrophages and in human and mice atherosclerotic coronary or carotid lesions, yielding in the formation of linoleic acid hydroperoxides (L-OOH) and linoleic acid hydroxide (L-OH). This indicates an esterase- and peroxidse-like activities for PON1. The PON1Q isoform was 50% more potent than PON1R in this respect. Using site-directed mutagenesis technique, the PON1’s free sulfhydryl group at cysteine 284 was found to be the enzyme active site. Macrophage foam cell formation is the hallmark of early atherogenesis and hence we questioned the effect of PON1 on macrophage atherogenicity. PON1 hydrolyzed macrophage lipid peroxides (PD) resulting in a 40% decreased content of PD, which was associated with a 36% reduced macrophage-mediated oxidation of LDL. On using PON1- deficient mice (PON1-/E-), a 42% increased atherosclerotic lesion size was shown in comparison to control E- mice and this was associated with increased (40-60%) oxidative stress in their serum, as well as in their macrophages (peritoneal and arterial). In macrophages from PON1- mice, NADPH oxidase activation was evident, resulting in enhanced cell-mediated oxidation of LDL. PON 1 action on macrophages reversed cellular oxidative stress toward normal levels. Conclusion: PON1 anti-atherogenicity could be related to its ability to hydrolyze and neutralize specific atherogenic lipid peroxides in lesion’s lipoproteins and arterial macrophages. 4P-0953
C. Anderson, H. Kath, D. Colquhoun. University of Queensland, Wesley Medical Centre, Brisbane, Qld., Australia Objective: To determine if dietary recommendations to increase fish intake should be modified to minimise the potential risk of methylmercury (MeHg) toxicity. Background: The American Heart Association (AHA) recommends that all adults eat fish at least twice a week. For those with coronary heart disease (CHD) 1g/day of n-3 fatty acid from fish is recommended. Fish ingestion is the dominant MeHg exposure pathway. MeHg in toxic doses causes neurological and developmental disorders and in lower doses may limit the beneficial cardiovascular effect of n-3 fatty acids. Fish MeHg content is unrelated to oil content. Fish oil capsules do not contain MeHg. Methods: Search of databases and websites; Medline, US Environmental Protection Agency (USEPA), World Health Organisation (WHO) websites. Results: The concentration of MeHg in fish varies according to geographical location and between species. There may be variation within one species eg. shark 0.05 – 4.54ug/g. MeHg is highest in predatory fish eg. swordfish and shark. There is a five-fold difference between WHO and US EPA MeHg intake limits; 3.36 and 0.7 ug/kg bodyweight/wk respectively. Fish species Swordfish Shark Fresh Tuna Cod Canned Tuna Salmon
Mercury* Max. serves/wk¶ n-3 content Serves/wk for 7g (µg/200g serve) WHO rec. USEPA rec. (g/serve) n-3 fatty acid 200 192 64 38 34 7
1.15 1.20 3.59 6 6.76 33
0.25 0.26 0.77 1.29 1.44 7
1.64 1.69 3.20 3.16 3.01 4.29
4.25 4.15 2.19 22 2.33 1.63
¶70 kg person; *estimates from US FDA tables.
Conclusion: The only fish which satisfies the AHA n-3 fatty acid and USEPA MeHg recommendations is salmon. Species and origin of fish need to be taken into account to prevent potential MeHg toxicity.
4P-0952
Paraoxonase (PON 1) protects against lipids peroxidation and attenuates atherosclerosis development
M. Aviram. Rambam Medical Center, Lipid Research Laboratory, Bat-Galim, Haifa, Israel Objective: Human serum paraoxonase (PON1) is physically associated with high density lipoprotein (HDL) and the activity of PON1 was shown to be inversely associated with the risk for atherosclerosis development (which is
Macrophage NADPH oxidase activation under oxidative stress increases cell-mediated oxidation of LDL and accelerates atherosclerosis development
M. Aviram, M. Rosenblat. The Lipid Research Laboratory, Rambam Medical Center, Israel Objective: Oxidative stress, the hallmark of early atherogenesis, affects arterial cells such as macrophages, as well as plasma lipoproteins atherogenicity. Recently, we provided evidence, both circumstantial and direct, that oxysterols play a major role in NADPH oxidase activation. Results: The oxysterols content of peritoneal macrophages (MPM), as well as arterial macrophages, from the atherosclerotic apolipoprotein E deficient (E°) mice, which were shown to be under oxidative stress, was significantly greater by 75% than that found for MPM from control C57BL6 mice. The presence of oxidized lipids in E° MPM was associated with a significant increased (80-140%) p47phox (the NADPH oxidase cytosolic component) content in the macrophage plasma membrane, in superoxide anions release and in MPM-mediated LDL oxidation. Furthermore, protein kinase C (PKC) activity and arachidonic acid (AA) release (both involved in NADPH oxidase activation) were elevated by 60% and 70% respectively, in E° MPM compared to control MPM. Addition of the major oxysterols found in E° MPM (7-keto-, epoxy- and 7β-hydroxy-cholesterol) to MPM from control mice resulted in a dose-dependent increase (45-80%) in the above parameters. Vitamin E supplementation (40mg/kg/day for 2 months) to E° mice resulted in the reverse of these oxidation parameters. Finally, in the atherosclerotic mice, the consumption of vitamin E (or dietary flavonoids from pomegranate or wine) resulted in a substantial (35%) reduction in their atherosclerotic lesion size and in the lesion content of macrophage foam cells. Conclusion: We thus conclude that activation of the macrophage NADPH oxidase contributes to enhanced cell-mediated oxidation of LDL, macrophage foam cell formation and atherosclerosis development. 4P-0954
Evaluation of apolipoprotein B-100 (apoB) fragmentation and cross-link in serum as a mechanism-based index of atherosclerosis
S. Kojo 1 , R. Hashimoto 1 , N. Matsukawa 1 , Y. Nariyama 1 , Y. Ogiri 1 , E. Hamagawa 1 , K. Tanaka 1 , Y. Usui 1 , S. Nakano 2 , T. Maruyama 3 , S. Kyotani 4 , M. Tsushima 4 . 1 Nara Women’s University, Nara; 2 National Tochigi Hospital; 3 Social Insurance Saitama Chuo Hospital; 4 National Cardiovascular Center, Japan Objective: We demonstrated that fragmented and cross-linked apoB proteins, which are products of radical reaction, are present in human serum and tend to increase with age based on immunoblot analysis [Tanaka, et al., J. Biochem. (Tokyo), 125, 173-176 (1999)]. These observations suggest that the fragmentation and cross-linkage pattern of apoB reflects the oxidative stress in an individual. In this study, the fragmentation and conjugation pattern of apoB was evaluated.
XIIIth International Symposium on Atherosclerosis, September 28–October 2, 2003, Kyoto, Japan
THURSDAY
ATHEROGENIC LIPOPROTEINS AND THEIR RECEPTORS
283
Thursday October 2, 2003: Poster Session Nutrition
wines. Many studies have inducted that anthocyanins intake is associated with a low risk of cardiovascular disease. The aim of this work was to verify the hypothesis that cyanidin-3-glucoside (Cy-3-G), a typical anthocyanin pigment, induces discharge of nitric oxide (NO) and expression of the endothelial nitric oxide synthase (eNOS) in vascular endothelial cells. Methods: Bovine aortic endothelial cells (BAECs) were used for all experiments. BAECs were treated with Cy-3-G at various concentrations in serum-free Dulbecco’s modified Eagle’s medium. The western blot analysis of eNOS, Src kinase, ERK1/2 MAP kinase, and SP1 was made. The dominant negative Src cDNA in pUSEamp was transfected into BAECs according to the manufacturer’s instructions. Results: Cy-3-G induced eNOS expression in BAECs in time- and concentration-dependent manner. Cy-3-G also stimulated phosphorylation of Src kinase, ERK1/2 MAP kinase, and SP1 in time-dependent manner. Moreover, Src kinase inhibitor pp2 and MEK inhibitor PD98059 blocked eNOS expression and phosphorylation of Src kinase, ERK1/2 MAP kinase, and SP1. However, ICI-182780, an antagonist of estrogen receptor, could not inhibit the Cy-3-G-caused eNOS expression. BAPTA-AM, an intracellular calcium chelate, could also not restrain eNOS expression. In addition, the dominantnegative Src cDNA transfection blocked similarly the Cy-3-G-caused eNOS expression in BAECs. Conclusion: Our data showed that Cy-3-G induces eNOS expression via an Src-ERK1/2 MAP kinas pathway, and the increase of eNOS expression can explains the beneficial effect of anthocyanins at vascular level. 4P-0947
Beneficial effects of flavonoid supplement on blood glucose and antioxidant activities in type 2 diabetic mouse
U.J. Jung 1 , M.-K. Lee 1 , S.-J. Lee 2 , M.-S. Choi 1 . 1 Kyungpook National University; 2 Taegu Catholic University, Republic of Korea Objective: Oxidative stress is an early state in the diabetes mellitus pathology and may contribute to the development of complications. This study investigated the blood glucose-lowering effect and antioxidant capacity of three flavonoids on type 2 diabetes. Methods: Male C57BL/KsJ-db/db mouse (5 weeks old), type 2 diabetic animal model, were adjusted for 2 weeks with lab. chow diet, and fed a normal diet supplemented with or without naringin(0.02%, wt/wt), hesperidin(0.02%, wt/wt), or quercetin(0.02%, wt/wt) for 5 weeks. Results: The naringin, hesperidin, and quercetin supplements significantly lowered the levels of fasting blood glucose and hemoglobin A1c compared to those of the control. The plasma triglyceride and total-cholesterol concentrations were significantly lowered in three flavonoid supplemented groups. The naringin supplement significantly lowered the levels of plasma fatty acid. The overall potential for antioxidant protection was also significantly enhanced by naringin, hesperidin, and quercetin supplements. The activity of plasma and hepatic paraoxonase, enzyme that is responsible for preventing the lipid peroxides accumulation on LDL, was dramatically increased in these flavonoid supplemented groups. Three flavonoid supplements significantly increased the activities of antioxidant enzyme in erythrocyte, liver and kidney. In addition, the hesperidin supplement dramatically lowered the levels of TBARS in erythrocyte, liver and kidney, and naringin and quercetin supplements significantly lowered the levels of TBARS in erythrocyte and liver compared to those of control group. Conclusion: These results suggest that flavonoids used may play important roles in regulation of blood glucose and lipids and be useful for reducing oxidative stress in type 2 diabetic mouse. Nature of antidiabetic and antioxidative effect of these functional flavonoids needs to be elucidated. 4P-0948
Effects of cholesterol and naringin supplementation on cholesterol and hepatic antioxidant enzyme activities in LDL receptor-knockout mice
H.-J. Kim 1 , G.T. Oh 2 , T.-S. Jeong 2 , Y.B. Park 1 , M.-S. Choi 1 . 1 Kyungpook National University; 2 Korea Research Institute of Bioscience and Biotechnology, Republic of Korea Objective: To investigate the effects of naringin on lipid metabolism and hepatic antioxidant enzyme activities using LDLR-knockout mice. Methods: Mice that are homozygous for a targeted distruption of the LDL receptor gene (LDLR-/- mice) were used as a model of familial hypercholesterolemia. Male LDLR-knockout mice were fed a high-cholesterol (0.1 g/100 g) or high-cholesterol diet supplemented with naringin or lovastatin (0.02 g/100 g) for 6 weeks. Results: Supplementation of naringin and lovastatin significantly lowered
levels of plasma total cholesterol compared to the control group. The plasma and hepatic triglyceride level was only lowered by the lovastatin supplement, while the hepatic cholesterol content was lowered by both the naringin and lovastatin supplements compared to the control group. The hepatic HMGCoA reductase activity was significantly lower in the naringin and lovastatin supplemented groups than in the control group, whereas the ACAT activity was unaffected. Fecal excretion of neutral and acidic sterol were significantly increased by supplementation of lovastatin and naringin, respectively. The levels of hepatic TBARS were decreased by lovastatin supplementation, however naringin supplementation only showed a tendency to decrease hepatic TBARS. In comparisons of hepatic antioxidant enzyme activities, naringin supplementation significantly increased the hepatic superoxide dismutase, catalase and glutathion reductase activities compared to the control group, whereas lovastatin supplementation only increased glutathione reductase activity. However, glutathione peroxidase and glucose-6-phosphatedehydrogenase activities were not different between groups. Conclusion: Naringin supplementation lowered plasma cholesterol level via inhibition of hepatic HMG-CoA reductase and increase of fecal acidic sterol in cholesterol fed LDLR-knockout mice. 4P-0949
Influence of argan oil administration on lipid peroxidation and paraoxonase activities in healthy Moroccan men
M. Cherki 1 , A. Drissi 1 , A. Derouiche 1 , M. El Messal 2 , Y. Bamou 3 , A. Idrissi-Oudghiri 3 , A. Khalil 4 , A. Adlouni 1 . 1 Lab. de Recherche sur les Lipoprotéines, Fac. des Sciences Ben M’sik, Casablanca; 2 Lab. de Biochimie, Fac. des Sciences Aïn Chock, Casablanca; 3 Hôpital Militaire Moulay Ismail, Meknes, Morocco; 4 Lab. de Recherche sur l’athérosclérose et système immunitaire, Centre de Recherche sur le Vieillissement, IUGS, Canada Objective: To determine whether the consumption of virgin argan oil (VAO) could improve plasma lipids, paraoxonase (PON1) activities and LDL peroxidation in healthy Moroccan men. Methods: Sixty normolipidaemic adults were included in this interventional study. All subjects received 25 g/day of butter during 2 weeks as baseline. The group was randomized in 2 different diet periods of 3 weeks each one. The VAO group received 25 ml/day of oil and the extra virgin olive oil (EVO) group received the same quantity of olive oil as control group. At the end of each diet period, plasma lipids, PON1 activities and lipoperoxides were measured. Susceptibility of plasma isolated LDL oxidation was also analyzed. Results: Analysis of plasma lipids showed a significant increase of HDLcholesterol concentration in VAO (6.3%) and EVO (17.3%) groups (p=0.026, p= 0.001, respectively) and a significant decrease (13.8%) of LDL-cholesterol concentration only in EVO group (p=0.037) compared to baseline values. However, plasma triglycerides concentration significantly decreased (17.5%, p= 0.039) in only VAO group. Plasma PON1 activities increased significantly in both groups (p=0.003), however Hydroperoxides decrease significantly in VAO and EVO groups (p= 0.001, p=0.014 respectively). Susceptibility of LDL peroxidation show a significant increase of lag phase and a significant decrease of maximum dienes production in VAO (p=0.005) and in EVO groups (p=0.041, p=0.005 respectively). Conclusion: This study shows for the first time that the consumption of argan oil protects against atherosclerosis process by improving paraoxonase activities, lipid and antioxidant status. 4P-0950
Baseline diet glycemic load and glycemic index are determinants of HDL cholesterol levels in patients with coronary heart disease: results from the LIPID study
K. Mehalski 1 , J. Brand-Miller 1 , S. Blakesmith 1 , A. Kirby 1 , C. Pollicino 1 , K. Baghurst 2 , S. Record 2 , W. Hague 1 , J. Simes 1 , P. Nestel 3 , A. Tonkin 4 , D. Colquhoun 5 . 1 NHMRC Clinical Trials Centre, University of Sydney; 2 CSIRO; 3 Baker Research Institute; 4 National Heart Foundation; 5 Wesley Medical Centre, Australia Objective: To assess the extent to which dietary carbohydrate, expressed as glycemic index (GI) and glycemic load (GL) affects lipids and lipoproteins in patients with coronary heart disease (CHD). Background and Rationale: The glycemic load of the diet influences lipoprotein levels and the risk of CHD in asymptomatic individuals. The effects of GI and GL in patients with CHD taking standard drug therapy are unknown. Methods: LIPID was a placebo-controlled double-blind trial that assessed the efficacy of pravastatin over 6 years in 9014 patients with CHD and baseline cholesterol 4–7 mmol/L. In a diet sub study, 1077 patients completed
XIIIth International Symposium on Atherosclerosis, September 28–October 2, 2003, Kyoto, Japan
Thursday October 2, 2003: Poster Session Atherogenic lipoproteins and their receptors a validated food-frequency questionnaire of more than 170 foods during the trial’s run-in period. Carbohydrate foods were allocated a GI value, and GL of the diet was calculated by multiplying the carbohydrate value of each food by its GI, then multiplying this by the frequency of consumption, and finally summing the values from all carbohydrate foods in the diet. Results: Serum HDL cholesterol was inversely correlated with both GI (r = -0.140, P<0.001) and GL (r = -0.122, P<0.001). This relationship was noted when factors were analysed as continuous variables, and when GI and GL were divided by quartile (graph). Pravastatin therapy did not affect this relationship.
Conclusion: GI and GL significantly influence HDL cholesterol, a major determinant of prognosis in these patients with CHD. Diets with low GI and GL may improve CHD outcomes. 4P-0951
Recommended fish intake is potentially dangerous due to high methylmercury content of certain fish
enhanced under oxidative stress). We thus questioned whether this is related to the ability of PON 1 to protect against lipids peroxidation in lipoproteins and in arterial cells. Results: PON1 hydrolyzed cholesteryl linoleate hydroperoxides (CL-OOH) in oxidized LDL, HDL and macrophages and in human and mice atherosclerotic coronary or carotid lesions, yielding in the formation of linoleic acid hydroperoxides (L-OOH) and linoleic acid hydroxide (L-OH). This indicates an esterase- and peroxidse-like activities for PON1. The PON1Q isoform was 50% more potent than PON1R in this respect. Using site-directed mutagenesis technique, the PON1’s free sulfhydryl group at cysteine 284 was found to be the enzyme active site. Macrophage foam cell formation is the hallmark of early atherogenesis and hence we questioned the effect of PON1 on macrophage atherogenicity. PON1 hydrolyzed macrophage lipid peroxides (PD) resulting in a 40% decreased content of PD, which was associated with a 36% reduced macrophage-mediated oxidation of LDL. On using PON1- deficient mice (PON1-/E-), a 42% increased atherosclerotic lesion size was shown in comparison to control E- mice and this was associated with increased (40-60%) oxidative stress in their serum, as well as in their macrophages (peritoneal and arterial). In macrophages from PON1- mice, NADPH oxidase activation was evident, resulting in enhanced cell-mediated oxidation of LDL. PON 1 action on macrophages reversed cellular oxidative stress toward normal levels. Conclusion: PON1 anti-atherogenicity could be related to its ability to hydrolyze and neutralize specific atherogenic lipid peroxides in lesion’s lipoproteins and arterial macrophages. 4P-0953
C. Anderson, H. Kath, D. Colquhoun. University of Queensland, Wesley Medical Centre, Brisbane, Qld., Australia Objective: To determine if dietary recommendations to increase fish intake should be modified to minimise the potential risk of methylmercury (MeHg) toxicity. Background: The American Heart Association (AHA) recommends that all adults eat fish at least twice a week. For those with coronary heart disease (CHD) 1g/day of n-3 fatty acid from fish is recommended. Fish ingestion is the dominant MeHg exposure pathway. MeHg in toxic doses causes neurological and developmental disorders and in lower doses may limit the beneficial cardiovascular effect of n-3 fatty acids. Fish MeHg content is unrelated to oil content. Fish oil capsules do not contain MeHg. Methods: Search of databases and websites; Medline, US Environmental Protection Agency (USEPA), World Health Organisation (WHO) websites. Results: The concentration of MeHg in fish varies according to geographical location and between species. There may be variation within one species eg. shark 0.05 – 4.54ug/g. MeHg is highest in predatory fish eg. swordfish and shark. There is a five-fold difference between WHO and US EPA MeHg intake limits; 3.36 and 0.7 ug/kg bodyweight/wk respectively. Fish species Swordfish Shark Fresh Tuna Cod Canned Tuna Salmon
Mercury* Max. serves/wk¶ n-3 content Serves/wk for 7g (µg/200g serve) WHO rec. USEPA rec. (g/serve) n-3 fatty acid 200 192 64 38 34 7
1.15 1.20 3.59 6 6.76 33
0.25 0.26 0.77 1.29 1.44 7
1.64 1.69 3.20 3.16 3.01 4.29
4.25 4.15 2.19 22 2.33 1.63
¶70 kg person; *estimates from US FDA tables.
Conclusion: The only fish which satisfies the AHA n-3 fatty acid and USEPA MeHg recommendations is salmon. Species and origin of fish need to be taken into account to prevent potential MeHg toxicity.
4P-0952
Paraoxonase (PON 1) protects against lipids peroxidation and attenuates atherosclerosis development
M. Aviram. Rambam Medical Center, Lipid Research Laboratory, Bat-Galim, Haifa, Israel Objective: Human serum paraoxonase (PON1) is physically associated with high density lipoprotein (HDL) and the activity of PON1 was shown to be inversely associated with the risk for atherosclerosis development (which is
Macrophage NADPH oxidase activation under oxidative stress increases cell-mediated oxidation of LDL and accelerates atherosclerosis development
M. Aviram, M. Rosenblat. The Lipid Research Laboratory, Rambam Medical Center, Israel Objective: Oxidative stress, the hallmark of early atherogenesis, affects arterial cells such as macrophages, as well as plasma lipoproteins atherogenicity. Recently, we provided evidence, both circumstantial and direct, that oxysterols play a major role in NADPH oxidase activation. Results: The oxysterols content of peritoneal macrophages (MPM), as well as arterial macrophages, from the atherosclerotic apolipoprotein E deficient (E°) mice, which were shown to be under oxidative stress, was significantly greater by 75% than that found for MPM from control C57BL6 mice. The presence of oxidized lipids in E° MPM was associated with a significant increased (80-140%) p47phox (the NADPH oxidase cytosolic component) content in the macrophage plasma membrane, in superoxide anions release and in MPM-mediated LDL oxidation. Furthermore, protein kinase C (PKC) activity and arachidonic acid (AA) release (both involved in NADPH oxidase activation) were elevated by 60% and 70% respectively, in E° MPM compared to control MPM. Addition of the major oxysterols found in E° MPM (7-keto-, epoxy- and 7β-hydroxy-cholesterol) to MPM from control mice resulted in a dose-dependent increase (45-80%) in the above parameters. Vitamin E supplementation (40mg/kg/day for 2 months) to E° mice resulted in the reverse of these oxidation parameters. Finally, in the atherosclerotic mice, the consumption of vitamin E (or dietary flavonoids from pomegranate or wine) resulted in a substantial (35%) reduction in their atherosclerotic lesion size and in the lesion content of macrophage foam cells. Conclusion: We thus conclude that activation of the macrophage NADPH oxidase contributes to enhanced cell-mediated oxidation of LDL, macrophage foam cell formation and atherosclerosis development. 4P-0954
Evaluation of apolipoprotein B-100 (apoB) fragmentation and cross-link in serum as a mechanism-based index of atherosclerosis
S. Kojo 1 , R. Hashimoto 1 , N. Matsukawa 1 , Y. Nariyama 1 , Y. Ogiri 1 , E. Hamagawa 1 , K. Tanaka 1 , Y. Usui 1 , S. Nakano 2 , T. Maruyama 3 , S. Kyotani 4 , M. Tsushima 4 . 1 Nara Women’s University, Nara; 2 National Tochigi Hospital; 3 Social Insurance Saitama Chuo Hospital; 4 National Cardiovascular Center, Japan Objective: We demonstrated that fragmented and cross-linked apoB proteins, which are products of radical reaction, are present in human serum and tend to increase with age based on immunoblot analysis [Tanaka, et al., J. Biochem. (Tokyo), 125, 173-176 (1999)]. These observations suggest that the fragmentation and cross-linkage pattern of apoB reflects the oxidative stress in an individual. In this study, the fragmentation and conjugation pattern of apoB was evaluated.
XIIIth International Symposium on Atherosclerosis, September 28–October 2, 2003, Kyoto, Japan
THURSDAY
ATHEROGENIC LIPOPROTEINS AND THEIR RECEPTORS
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