Fatty Acid Composition and the Oxidation of Low-Density Lipoproteins

The effect of the fatty acid composition of low-density lipoprotein (LDL) on copper-ion-catalyzed oxidation of isolated LDL was examined in 18 normolipidemic men. The decrease in LDL linoleic acid concentration (ΔL) during oxidation was found to be strongly correlated with initial LDL linoleic acid concentration (r = 0.976, n = 18, P < 0.001), whereas the production of thiobarbituric acid reacting substances (TBARS) was not. The concentration of oleic acid in LDL was then increased significantly (mean increase 20%, P < 0.05) in 8 male volunteers by a daily dietary supplement of rapeseed oil/muesli for 4 weeks. The mean delay before copper-ion-catalyzed production of conjugated dienes (the lag phase) was significantly (P < 0.001) greater in LDL isolated after the study period (67 min) than that of before the study period (40 mm). The rate of formation of conjugated dienes, ΔL and TBARS production during oxidation of LDL was not significantly altered by the rapeseed oil/muesli supplement. These results suggest that the linoleic acid content of LDL is a determinant of individual variability in LDL oxidation, and that a rapeseed oil/muesli dietary supplement reduces the susceptibility of LDL to oxidation.     

Lipoprotein Oxidation and Plasma Vitamin E in Nondiabetic Normotensive Obese Patients

Objective: To correlate the susceptibility of low‐(LDL) and very‐low‐density lipoprotein to oxidation in vitro and the concentrations of serum antibodies against malondialdehyde‐modified LDL and plasma vitamin E with the anthropometric and laboratory characteristics of obesity. Research Methods and Procedures: A total of 75 nondiabetic, normotensive obese patients were assigned to one of four groups according to their body mass index (BMI): moderately obese (30 ≤ BMI ≤ 34.9 kg/m², n = 11), severely obese (35 ≤ BMI ≤ 39.9 kg/m², n = 20), morbidly obese (40 ≤ BMI ≤ 50 kg/m², n = 29), and very severely obese (BMI > 50 kg/m², n = 15). Results: The oxidation lag time for LDL from patients with a BMI ≥35 kg/m² was shorter than that for LDL from non‐obese controls (n = 13), whereas very‐low‐density lipoprotein oxidation lag times were not significantly different. The serum antibodies against modified LDL were similar in all groups, whereas the plasma vitamin E concentrations of obese patients were decreased (p ≤ 0.01). There was a negative correlation between LDL oxidation lag time and BMI (r = ?0.35, p = 0.0008), and between plasma vitamin E and BMI (r = ?0.53, p < 0.0001) and waist‐to‐hip ratio (r = ?0.40, p = 0.0003). Discussion: The LDL of nondiabetic, normotensive obese patients is more readily oxidized, and plasma vitamin E concentrations are low. These are both risk factors for coronary heart disease.     

Impaired resistance to oxidation of low density lipoprotein in cystic fibrosis: Improvement during vitamin E supplementation

Antioxidants such as vitamin E protect unsaturated fatty acids of LDL against oxidation. In the ex vivo model used, LDL was exposed to Cu²⁺ ions, a potent prooxidant capable of initiating the oxidation of LDL. The lag time, indicating the delay of conjugated diene formation in LDL due to antioxidant protection, was measured in 54 cystic fibrosis (CF) patients with plasma -tocopherol levels below (Group A, n = 30) or above (Group B, n = 24) 15.9 μmol/L (mean - 2 SD of Swiss population). Patients were reevaluated after 2 months on 400 IU/d of oral RRR--tocopherol. In group A, -tocopherol concentrations in LDL increased significantly from 3.2 ± 1.6 mol/mol LDL to 8.2 ± 2.8 mol/mol (P < 0.001) and lag times increased from 79 ± 33, min to 126 ± 48 min (P < 0.001), whereas in the vitamin E sufficient group B no further increase neither in LDL -tocopherol concentrations or in lag times was observed. LDL oleic acid concentrations were higher, and linoleic acid concentrations were lower in patients than in controls. After efficient vitamin E supplementation, lag times were positively related to LDL -tocopherol (P < 0.01) and negatively to LDL linoleic and arachidonic acid content (P < 0.001). The maximum rate of oxidation correlated positively with linoleic and arachidonic acid concentrations, as did the maximum conjugated diene absorbance. These results indicate that LDL resistance to oxidation is impaired in vitamin E deficient CF patients but can be normalized within 2 months when -tocopherol is given in sufficient amounts. Linoleic and arachidonic acid content exhibit a major influence on the LDL resistance to oxidation.     

Fatty acid profile and meat quality of young bulls fed ground soybean or ground cottonseed and vitamin E

The objective of this study was to evaluate the fatty acid profile and qualitative characteristics of meat from feedlot young bulls fed ground soybean or ground cottonseed, with or without supplementation of vitamin E. A total of 40 Red Norte young bulls, with an initial average age of 20 months, and an initial average BW of 339±15 kg, were allotted in a completely randomized design using a 2×2 factorial arrangement, with two oilseeds, and daily supplementation or not of 2500 IU of vitamin E. The experimental period was for 84 days, which was preceded by an adaptation period of 28 days. The treatments were ground soybean (SB), ground soybean plus vitamin E (SBE), ground cottonseed (CS) and ground cottonseed plus vitamin E (CSE). The percentage of cottonseed and soybean in the diets (dry matter basis) was 24% and 20%, respectively. Diets were isonitrogenous (13% CP) and presented similar amount of ether extract (6.5%). The animals were slaughtered at average live weight of 464±15 kg, and samples were taken from the longissimus dorsi muscle for the measurement of fatty acid concentration and the evaluation of lipid oxidation and color of the beef. Before fatty acid extraction, muscle tissue and subcutaneous fat of the longissimus dorsi were separated to analyze fatty acid profile in both tissues. Supplementation of vitamin E did not affect fatty acid concentration, lipid oxidation and color (P>0.05). Subcutaneous fat from animals fed CS diet had greater C12:0, C16:0 and C18:0 contents (P<0.03). In addition, CS diets reduced the C18:1 and C18:2 cis-9, trans-11 contents in subcutaneous fat (P<0.05). The muscle from animals fed CS tended to higher C16:0 and C18:0 contents (P<0.11), and decreased C18:1, C18:2 cis-9, trans-11 and C18:3 contents (P<0.05) compared with SB. The Δ⁹-desaturase index was greater in muscle from animals fed SB (P<0.01). At 42 days of age, meat from cattle fed SB had a greater lipid oxidation rate (P<0.05). Meat from animals fed SB diets had less lightness and redness indices than meat from animals fed CS diets after 14 days of age. In conclusion, the addition of ground cottonseed in the finishing diets did increase the saturated fatty acid content of the longissimus dorsi. However, animals fed cottonseed exhibited greater lightness and redness of beef. In this study, the addition of vitamin E did not affect qualitative characteristics of meat.     

Protective role of intraperitoneally administrated vitamin E and selenium on the levels of total lipid,total cholesterol,and fatty acid composition of muscle and liver tissues in rats

The aim of this work was to determine the protective effects of intraperitoneally administrated vitamin E and Se on total lipid, total cholesterol, and fatty acid composition of rat liver and muscle tissues. Total lipid content of muscle tissue in Se and combination groups decreased as compared to the control group. However, the level of total lipid in the liver tissues was seen to decrease only in the combination group (P < 0.05). While the amount of total cholesterol in liver tissue was lower (P < 0.05) in the vitamin E and combination groups, the amount of total cholesterol in muscle tissue decreased (P < 0.05) in the combination group. The amount of linoleic acid in muscle tissue slightly decreased (P < 0.05), whereas the eicosenoic and eicosatrienoic acid amounts significantly increased (P < 0.01, P < 0.001) in the vitamin E group as compared to the control group. The amounts of most fatty acid decreased (P < 0.05) in the combination group. The proportions of eicosenoic, eicosatrienoic, and total polyunsaturated fatty acid (PUFA) within the total fatty acid were higher (P < 0.05) in vitamin E group, whereas these fatty acids proportions were lower (P < 0.05) in the Se group. Although the proportions of palmitic, linolenic, and total saturated fatty acids were low (P < 0.05), oleic and total unsaturated fatty acid proportions were higher (P < 0.05) in the combination group than in the control group. The amount of palmitic acid and total saturated fatty acid in liver tissue decreased (P < 0.01 and P < 0.05, respectively) in the vitamin E and combination groups. However, the amount of linoleic acid only decreased (P < 0.05) in the combination group. The amount of PUFA was slightly higher (P < 0.05) in vitamin E. The proportions of stearic acid and linoleic acid decreased (P < 0.05) both in the Se and combination groups. However, the proportions of eicosatrienoic, ω 6, and PUFA were slightly higher (P < 0.05) in the vitamin E group, but total saturated fatty acid proportion significantly decreased (P < 0.01) in both the vitamin E and combination groups. In conclusion, the level of total lipid and cholesterol in muscle and liver tissues were reduced by administrating vitamin E and Se together. Additionally, the fatty acid synthesis in the muscle and liver tissues was decreased by this process. However, it was observed that the protective effect of intraperitoneally administrated vitamin E was higher than Se on fatty acid composition in muscle and liver tissues. J. Cell. Biochem. 64:233–241. © 1997 Wiley-Liss, Inc.     

Selective transport of long-chain fatty acids by FAT/CD36 in skeletal muscle of broilers

Fatty acid translocase (FAT/CD36) is a membrane receptor that facilitates long-chain fatty acid uptake. To investigate its role in the regulation of long-chain fatty acid composition in muscle tissue, we studied and compared FAT/CD36 gene expression in muscle tissues of commercial broiler chickens and Chinese local Silky fowls. The results from gas chromatography–mass spectrometry analysis of muscle samples demonstrated that Chinese local Silky fowls had significantly higher (P < 0.05) proportions of linoleic acid (LA) and palmitic acid, lower proportions (P < 0.05) of arachidonic acid (AA) and oleic acid than the commercial broiler chickens. The mRNA expression levels of fatty acid (FA) transporters (FA transport protein-1, membrane FA-binding protein, FAT/CD36 and caveolin-1) in the m. ipsilateral pectoralis and biceps femoris were analyzed by Q-PCR, and FAT/CD36 expression levels showed significant differences between these types of chickens (P < 0.01). Interestingly, the levels of FAT/CD36 expression are positively correlated with LA content (r = 0.567, P < 0.01) but negatively correlated with palmitic acid content (r = −0.568, P < 0.01). Further experiments in the stably transfected Chinese hamster oocytes cells with chicken FAT/CD36 cDNA demonstrated that overexpression of FAT/CD36 improves total FA uptake with a significant increase in the proportion of LA and AA, and a decreased proportion of palmitic acid. These results suggest that chicken FAT/CD36 may selectively transport LA and AA, which may lead to the higher LA deposition in muscle tissue.     

Dietary verbascoside supplementation in donkeys: effects on milk fatty acid profile during lactation,and serum biochemical parameters and oxidative markers

Various uses of donkeys’ milk have been recently proposed for human consumption on the basis of its nutritional characteristics. Improvements in milk fatty acid profile and animal oxidative status can be induced through dietary supplementation of phenolic compounds. The study aimed to evaluate in donkeys the effects of dietary supplementation with verbascoside (VB) on: (i) the fatty acid profile and vitamins A and E contents of milk during a whole lactation, and (ii) blood biochemical parameters and markers of oxidative status of the animals. At foaling, 12 lactating jennies were subdivided into two groups (n 6): control, without VB supplement; VB, receiving a lipid-encapsulated VB supplement. Gross composition, fatty acid profile and vitamins A and E contents in milk were assessed monthly over the 6 months of lactation. Serum total cholesterol, high-density lipoproteins cholesterol and low-density lipoproteins cholesterol, tryglicerides, non-esterified fatty acid, bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase, reactive oxygen metabolites, thiobarbituric acid reactive substances (TBARs), vitamin A and vitamin E were evaluated at 8 days after foaling (D0) and then at D90, D105 and D120 of lactation. In milk, the VB supplementation decreased the saturated fatty acids (P<0.05) and increased the monounsaturated fatty acids (P<0.05), and vitamins A and E (P<0.01) values. On the serum parameters, the VB supplementation decreased total cholesterol (P<0.01), tryglicerides, bilirubin, ALT and TBARs, and increased (P<0.01) vitamin E. In conclusion, the VB dietary supplementation affects the nutritional quality of donkey’s milk with a benefit on the oxidative status and serum lipidic profile of the animals.     

Effect of dehydroepiandrosterone sulfate on carnitine acetyl transferase activity and l-carnitine levels in oophorectomized rats

Alteration in energy metabolism of postmenopausal women might be related to the reduction of dehydroepiandrosterone sulfate (DHEAS). DHEA and DHEAS decline with age, leveling at their nadir near menopause. DHEA and DHEAS modulate fatty acid metabolism by regulating carnitine acyltransferases and CoA. The purpose of this study was to determine whether dietary supplementation with DHEAS would also increase tissue l-carnitine levels, carnitine acetyltransferase (CAT) activity and mitochondrial respiration in oophorectomized rats. Plasma l-carnitine levels rose following oophorectomy in all groups (P<0.0001). Supplementation with DHEAS was not associated with further elevation of plasma l-carnitine levels, but with increased hepatic total and free l-carnitine (P=0.021 and P<0.0001, respectively) and cardiac total l-carnitine concentrations (P=0.045). In addition, DHEAS supplementation increased both hepatic and cardiac CAT activities (P<0.0001 and P=0.05 respectively). CAT activity positively correlated with the total and free carnitine levels in both liver and heart (r=0.764, r=0.785 and r=0.700, r=0.519, respectively). Liver mitochondrial respiratory control ratio, ADP:O ratio and oxygen uptake were similar in both control and supplemented groups. These results demonstrate that in oophorectomized rats, dietary DHEAS supplementation increases the liver and heart l-carnitine levels and CAT activities. In conclusion, DHEAS may modulate l-carnitine level and CAT activity in estrogen deficient rats. The potential role of DHEAS in the regulation of fatty acid oxidation in postmenopausal women is worthy of investigation.     

The fatty acid distribution in low density lipoprotein in diabetes

Atherosclerosis is commonly found in diabetes. There is an association between small dense low density lipoprotein (LDL) phenotype, which is more prevalent in the diabetic state, and atherosclerosis. Small dense LDL is more easily oxidised and it is possible that fatty acid compositional changes, particularly an increase in polyunsaturated fatty acids, could underlie this association. However, there is little information about fatty acids in the different LDL phenotypes in the literature. This study examined LDL subfraction composition in 18 non-insulin-dependent diabetic (NIDDM) patients and 11 control subjects. LDL was isolated and fractionated into LDL 1, 2 and 3 by density gradient ultracentrifugation. NIDDM patients had significantly more fatty acids in all LDL subfractions than control subjects (P<0.01). Palmitic and linoleic acid were significantly greater in all subfractions in the diabetic patients compared to control subjects (P<0.01) and palmitoleic and oleic acids were also greater in LDL1 and LDL2 in diabetic patients (P<0.01). We conclude that in NIDDM fatty acids are increased in all LDL subfractions and this may be the reason for the increased atherosclerosis in diabetes irrespective of phenotype.     

The Relationship Between Lipid Composition of Red Blood Cells and Their Susceptibility to Lipid Peroxidation

Red blood cells from 31 healthy donors were examined for the cholesterol content, the fatty acid composition. and the susceptibility to lipid peroxidation induced by either hydrogen peroxide or phenylhy-drazine. Lipid peroxidation was monitored by the release of pentane and ethane. In addition, plasma fatty acids were measured in order to find out, whether plasma and red cell fatty acids were correlated. In experiments with hydrogen peroxide, a significant positive correlation was found between the proportion of arachidonic acid (C 20:4n – 6; r = 0.57, p < 0.01) and docosahexaenoic acid (C 22:6; - 3; r = +0.71, p < 0.01), and the release of pentane and ethane, respectively. A significant negative correlation was found between the membrane cholesterol content and the pentane release (r -0.44, p< 0.05). In experiments performed with phenylhydrazine, red cell membrane lipid composition did not influence the susceptibility of red cells to lipid peroxidation. A close correlation was found between plasma and red cell fatty acids (palmitic acid, r = +0.46, p < 0.01; linoleic acid, r = +0.41, p < 0.05; arachidonic acid, r = +0.59, p < 0.01; docosahexaenoic acid, r = +0.67, p < 0.01). The results demonstrated that the degree of peroxide-induced oxidation of erythrocyte lipids depends on the content of polyunsaturated fatty acids in the membrane, which on the other hand, is determined by plasma fatty acids. It is suggested that dietary variations may influence the susceptibility of red cells to lipid peroxidation.     

Comparison of LDL TRAP assay to other tests of antioxidant capacity; Effect of vitamin E and lovastatin treatment

Oxidized low density lipoprotein (LDL) has a major impact in the development of atherosclerosis. Risk for oxidative modification of LDL is usually determined indirectly by measuring the capability of LDL to resist radical insult. We compared three different methods quantifying the antioxidative capacity of LDL ex vivo in dyslipidemic patients with coronary heart disease. Plasma samples were obtained from two double-blinded cross-over trials. The duration of all interventions (placebo, lovastatin 60 mg/day, RRR-α-tocopherol 300 mg/day and lovastatin + RRR-α-tocopherol combined) was 6 weeks. The total radical capturing capacity of LDL (TRAP) in plasma was determined using 2,2-azobis(2,4-dimethyl-valeronitrile) (AMVN)-induced oxidation, and measuring the extinction time of chemiluminescence. TRAP was compared to the variables characterizing formation of conjugated dienes in copper-induced oxidation. Also the initial concentrations and consumption times of reduced α-tocopherol (α-TOH) and ubiquinol in AMVN-induced oxidation were determined.

Repeatability of TRAP was comparable to that of the lag time in conjugated diene formation. Coefficient of variation within TRAP assay was 4.4% and between TRAP assays 5.9%. Tocopherol supplementation produced statistically significant changes in all antioxidant variables except those related to LDL ubiquinol. TRAP increased by 57%, the lag time in conjugated diene formation by 34% and consumption time of α-TOH by 88%. When data of all interventions were included in the analyses, TRAP correlated with the lag time (r = 0.75, p < 10^-6), with LDL α -TOH (r = 0.50, p < 0.001) and with the consumption time of α-TOH (r = 0.58, p < 0.0001). In the baseline data, the associations between different antioxidant variables were weaker. TRAP correlated with the lag time (r = 0.55, p < 0.001) and α-TOH consumption time (r = 0.48, p < 0.05), and inversely with apolipoprotein Al (r = -0.51, p < 0.05). Lag time at the baseline did not correlate with ubiquinol or tocopherol parameters, or with any plasma lipid or lipoprotein levels analyzed. Lovastatin treatment did not significantly affect the antioxidant capacity of LDL. In conclusion, TRAP reflects slightly different properties of LDL compared to the lag time. Thus, LDL TRAP assay may complement the other methods used to quantify the antioxidant capacity of LDL. However, TRAP and the lag time react similarly to vitamin E supplementation.     

Correlation between body size and fatty acid and essential amino acid composition of round goby (Neogobius melanostomus) and monkey goby (Neogobius fluviatilis) from the Rhine River (Germany)

In this study correlations between body size and muscle fatty and amino acid content of two species of goby, round goby (Neogobius melanostomus) and monkey goby (Neogobius fluviatilis) caught from river Rhine (Germany) were investigated. Among saturated fatty acids (SFAs), mono- (MUFA) and polyunsaturated fatty acids (PUFAs) only SFAs were significantly higher in round goby than monkey goby (P < 0.05). In general, the correlation between body size of both gobies and the content of most of the individual fatty acids was not significant. In monkey goby, the content of palmitic acid (C16:0) and oleic acid (C18:1 n-9) was positively correlated with weight (r = 0.43) and total length (r = ?0.58), respectively, and the content of docosahexaenoic acid (DHA) increased with condition factor (r = 0.50). The content of threonine, arginine, valine, phenylalanine and isoleucine in monkey goby was higher than those of round goby (P < 0.05). In round goby the three essential amino acids arginine, valine and leucine were positively (P < 0.05) correlated with body length, which indicates that longer round gobies are of higher nutritional value.     

Effects of vitamin E on diurnal variation in rectal temperature of Black Harco pullets during the hot-dry season

Experiments were performed with the aims of determining rectal temperature (RT) fluctuations in pullets, and the effect of vitamin E administration on the fluctuations during the hot-dry season. The RT values in experimental pullets administered vitamin E orally at a daily dose of 30 mg/kg, were significantly (P<0.05) lower than that of control pullets administered only water (41.21±0.02 and 41.43±0.04 °C, respectively). The dry-bulb temperature was significantly (P<0.001) and positively correlated with RT in both experimental (r=0.800) and control (r=0.936) pullets. Vitamin E administration ameliorated the heat stress of the hot-dry season, and may enhance productivity of pullets during the season.     

Meat and fat quality of Krškopolje pigs reared in conventional and organic production systems

Data on production traits of the only Slovenian autochthonous pig breed, the Krškopolje pig, is very scarce. Krškopolje pigs are reared in conventional and organic production systems, which were compared in the present study. After weaning, 24 barrows were assigned within litter to either conventional (CON) or organic (ECO) rearing system. Group CON (n=12) was housed indoors in two pens (7.5 m²) with partly slatted floor. Group ECO (n=12) was held in a sty with sheltered area (concrete floor, bedded with straw, 16 m²) and outdoor paddock area (100 m²). The trial started when pigs had 68±8 kg BW and 157±6 days of age. Two diets were formulated with equivalent ingredients and composition. For ECO diet the ingredients used were ecological. Group ECO received a diet with 12.4 MJ metabolisable energy (ME) per kilogram and 12.9% CP and group CON a diet with 12.7 MJ ME/kg and 13.6% CP. Feed distribution was limited to 3.5 kg per pig daily. In line with the rules for organic production, ECO pigs were additionally given alfalfa hay ad libitum. After 73 days on trial, the pigs were slaughtered and carcass, meat and fat quality was evaluated. Meat quality traits (pH, colour, water holding capacity), fatty acid composition, lipid and protein oxidation, collagen content and solubility were analysed in longissimus lumborum (LL) muscle. Fatty acid composition, lipid oxidation, and vitamins A and E concentrations were determined in backfat. There were no significant differences in growth rate and carcass traits between ECO and CON pigs, however, ECO pigs tended (P<0.10) to have higher daily gain and lower dressing percentage, higher (P<0.001) pH 45 min and lower (P<0.01) pH 24 h postmortem, affecting (P<0.10) also water holding capacity and objective colour parameters (P<0.05) of LL muscle. There were no differences in intramuscular fat (IMF) content of LL muscle, however, IMF of ECO pigs had lower (P<0.05) proportion of saturated and higher (P<0.01) proportion of monounsaturated fatty acids accompanied by higher (P<0.001) values of thiobarbituric reactive substances (TBARS). In backfat, ECO pigs showed lower (P<0.05) vitamin E content, higher (P<0.001) TBARS, higher (P<0.01) degree of unsaturation (percentage of polyunsaturated fatty acids), and also higher (P<0.05) vitamin A concentration than CON pigs, which can be related to alfalfa hay supplementation of ECO pigs. In brief, organic rearing of Krškopolje pigs did not affect performances but had an effect on meat and fat quality.     

Plasma total antioxidant capacity is associated with dietary intake and plasma level of antioxidants in postmenopausal women

Increased plasma total antioxidant capacity (TAC) has been associated with a high consumption of fruits and vegetables. However, limited information is available on whether plasma TAC reflects the dietary intake of antioxidants and the levels of individual antioxidants in plasma. By using three different assays, the study aimed to determine if plasma TAC can effectively predict dietary intake of antioxidants and plasma antioxidant status. Forty overweight and apparently healthy postmenopausal women were recruited. Seven-day food records and 12-h fasting blood samples were collected for dietary and plasma antioxidant assessments. Plasma TAC was determined by vitamin C equivalent antioxidant capacity (VCEAC), ferric-reducing ability of plasma (FRAP) and oxygen radical absorbance capacity (ORAC) assays. TAC values determined by VCEAC were highly correlated with FRAP (r=0.79, P<.01) and moderately correlated with ORAC (r=0.34, P<.05). Pearson correlation analyses showed that plasma TAC values by VCEAC and ORAC had positive correlation with plasma uric acid (r=0.56 for VCEAC; r=0.49 for ORAC) and total phenolics (r=0.63 for VCEAC; r=0.36 for ORAC). However, TAC measured by FRAP was correlated only with uric acid (r=0.69). After multivariate adjustment, plasma TAC determined by VCEAC was positively associated with dietary intakes of γ-tocopherol (P<.001), β-carotene (P<.05), anthocyanidins (P<.05), flavones (P<.05), proanthocyanidins (P<.01) and TAC (P<.05), as well as with plasma total phenolics (P<.05), α-tocopherol (P<.001), β-cryptoxanthin (P<.05) and uric acid (P<.05). The findings indicate that plasma TAC measured by VCEAC reflects both dietary and plasma antioxidants and represents more closely the plasma antioxidant levels than ORAC and FRAP.     

Interrelations and associations of serum levels of steroids and pituitary hormones with markers of insulin resistance,inflammatory activity,and renal function in men and women aged >70 years in an 8-year longitudinal study of opposite-sex twins

Background: The physiological serum levels of steroids and pituitary hormones in older men and women have been sparsely reported in the literature.Objectives: The aims of this study were to investigate the normal variation and sex differences in steroids and pituitary hormones in those aged >70 years, and to study the interrelation between these hormones and indicators of the metabolic syndrome, inflammatory activity, and renal function.Methods: The investigation comprised a population-based sample of pairs of white opposite-sex twins from the Swedish Twin Registry. At baseline in 1996 and at the 8-year follow-uup in 2004, serum levels of progesterone, cortisol, testosterone, estradiol, follicle-stimulating hormone, luteinizing hormone, prolactin, creatinine, C-reactive protein (CRP), and urea were analyzed. Serum levels of insulin and cystatin were analyzed only at the follow-up.Results: The study sample included 219 men and 183 women aged 71 to 80 years (mean [SD], 74.5 [2.5] years) at baseline in 1996, and 127 men and 135 women at follow-uup in 2004. At baseline, in both men and women, the variation of progesterone in serum was positively correlated with that of estradiol (men: r = 0.226, P < 0.01; women: r = 0.115, P = NS), testosterone (men: r = 0.178, P < 0.01; women: r = 0.315, P < 0.001), and cortisol (men: r = 0.314, P < 0.001; women: r = 0.296, P < 0.001). The values of progesterone and other steroid hormones were associated with markers of insulin resistance (iie, insulin, waist circumference), inflammatory activity (ie, CRP) for progesterone (men: r = 0.267, P < 0.001; women: r = 0.150, P < 0.05), and renal function (ie, creatinine) for progesterone (men: r = 0.424, P < 0.001; women: r = 0.212, P < 0.01). Estradiol and prolactin were associated with insulin resistance, inflammation, and renal function. Furthermore, progesterone was associated with prolactin (men: r = 0.275, P < 0.001; women: r = 0.172, P < 0.05).. Among both men and women, there was a strong correlation between testosterone and estradiol (men: r = 0.753, P < 0.001; women: r = 0.526, P < 0.001); in women, there was also a link between testosterone and cortisol at follow-up (r = 0.340, P < 0.01). For progesterone, there was a significant correlation between the values of the co-twins (in 1996: r = 0.16, P < 0.05; in 2004: r = 0.45, P < 0.001). Higher serum levels of progesterone (2.0 [0.7] nmol/L in men and 1.7 [0.8] nmol/L in women) and prolactin (6 [5] μg/L in men and 8 [10] μg/L in women) were found among those who were deceased at follow-up compared with survivors (progesterone: 1.8 [0.5] nmol/L in men and 1.4 [0.6] nmol/L in women, P < 0.01; prolactin: 4 [3] μg/L in men and 5 [2] μg/L in women, P < 0.001).Conclusions: In this study of opposite-sex Swedish twins aged >70 years, there was a sex difference in the serum levels of steroids and pituitary hormones between men and women. Progesterone and other steroid hormones were associated with markers of insulin resistance, inflammatory activity, and renal function. Progesterone and prolactin levels were associated with increased risk of mortality in this sample.     

The effect of maternal and cord-blood vitamin C, vitamin E and lipid peroxide levels on newborn birth weight

Background Newborn birth weight has been shown to significantly correlate with the blood levels of vitamin C. Objective This study was planned to answer the question of why vitamin C levels correlate with birth weight; does such correlation reflect a protective effect of vitamin C on fetal growth, by its antioxidant characteristics or does it correspond to the nutritional status of both the mother and the fetus. We examined the hypothesis that maternal blood levels of vitamin C, but not vitamin E influence newborn birth weight. We determined maternal and newborn blood levels of vitamin C, vitamin E, and lipid peroxides (an index of oxidative insult) and the birth weights of full-term newborns delivered at our hospital. Results Compared with maternal blood levels, newborns have higher levels of vitamin C and lipid peroxides, but lower levels of vitamin E. There was a significant correlation in levels between mothers and their newborns for blood levels of vitamin C (r = 0.82, P < 0.01) and vitamin E (r = 0.61, P < 0.02) but not for lipid peroxides (r = 0.001). This suggests that maternal vitamin C and vitamin E intake can influence fetal vitamin C and vitamin E levels. Linear regression analysis shows a significant positive relationship between newborn birth weight and maternal plasma vitamin C (r = 0.51, P < 0.02). Similarly, there was a modest but significant positive relationship between newborn birth weights and newborn vitamin C levels (r = 0.61, P < 0.05). However, there was no relationship between maternal or fetal vitamin E or lipid peroxides levels and the newborn birth weight. Conclusions This study with a small number of subjects suggests a significant association between newborn birth weight and maternal and newborn plasma vitamin C levels. Lack of relationship between birth weight and vitamin E and lipid peroxides suggest that antioxidant function of vitamin C does not appear to have a major role in the effect of vitamin C on birth weight.     

Oxidation of high density lipoproteins: characterization and effects on cholesterol efflux from J774 macrophages

Oxidative modification of high density lipoproteins (HDL) may alter their capacity to mediate cellular cholesterol efflux. We studied the kinetics of copper-mediated oxidation of HDL and cholesterol efflux mediated by unmodified and oxidized HDL (oxHDL). Oxidation was measured by increases in absorbance at 234 nm (ΔA234), production of thiobarbituric acid reactive substances (TBARS) and loss of trinitrobenzene sulfonic acid reactivity. Oxidation was dependent on copper concentration and showed a lag phase and propagation phase. Efflux of cholesterol from J774 macrophages measured by appearance of cellular [³H]cholesterol in the medium was lower by 16% after 4 h and 36% after 24 h with oxHDL compared to HDL. OxHDL-mediated efflux was also lower by 27% to 36% at lipoprotein concentrations of 10 to 200 μg protein/ml. Cholesterol efflux correlated negatively with TBARS production (r= −0.97, P < 0.003) and ΔA234 (r = −0.77, P < 0.080). There was no difference in efflux mediated by apoproteins prepared from HDL and oxHDL. Efflux measured by change in cholesterol mass in medium was 78% lower with oxHDL. Inhibition of oxidation with butylated hydroxytoluene maintained the capacity of HDL to stimulate efflux. These results suggest that oxidation of HDL may impair its protective role against atherosclerosis.     

Quercetin up-regulates paraoxonase 1 gene expression with concomitant protection against LDL oxidation

Paraoxonase 1 (PON1) protects the oxidative modification of low-density lipoprotein (LDL) and is a major anti-atherosclerotic protein component of high-density lipoprotein (HDL). Quercetin, a ubiquitous plant flavonoid, has been shown to have a number of bioactivities and may offer a variety of potential therapeutic uses. We explored the roles of quercetin in the regulation of PON1 expression, serum and liver activity and protective capacity of HDL against LDL oxidation in rats. Compared to the pair-fed control group, feeding quercetin (10 mg/L) in the liquid diet for 4 weeks increased (a) hepatic expression of PON1 by 35% (p < 0.01), (b) serum and liver PON1 activities by 29% (p < 0.05) and 57% (p < 0.01), respectively, and (c) serum homocysteine thiolactonase (HCTL) activity by 23% (p < 0.05). Correspondingly, the lag time of low-density lipoprotein (LDL) oxidation was increased by >3-fold (p < 0.001) with plasma HDL from quercetin-fed group compared to the HDL from control group. Our data suggest that quercetin has antiatherogenic effect by up regulating PON1 gene expression and its protective capacity against LDL oxidation.