RESUMEN
Inflammation is a stereotypical physiological response to infections and tissue injury; it initiates pathogen killing as well as tissue repair processes and helps to restore homeostasis at infected or damaged sites. Acute inflammatory reactions are usually self-limiting and resolve rapidly, due to the involvement of negative feedback mechanisms. Thus, regulated inflammatory responses are essential to remain healthy and maintain homeostasis. However, inflammatory responses that fail to regulate themselves can become chronic and contribute to the perpetuation and progression of disease. Characteristics typical of chronic inflammatory responses underlying the pathophysiology of several disorders include loss of barrier function, responsiveness to a normally benign stimulus, infiltration of inflammatory cells into compartments where they are not normally found in such high numbers, and overproduction of oxidants, cytokines, chemokines, eicosanoids and matrix metalloproteinases. The levels of these mediators amplify the inflammatory response, are destructive and contribute to the clinical symptoms. Various dietary components including long chain omega-3 fatty acids, antioxidant vitamins, plant flavonoids, prebiotics and probiotics have the potential to modulate predisposition to chronic inflammatory conditions and may have a role in their therapy. These components act through a variety of mechanisms including decreasing inflammatory mediator production through effects on cell signaling and gene expression (omega-3 fatty acids, vitamin E, plant flavonoids), reducing the production of damaging oxidants (vitamin E and other antioxidants), and promoting gut barrier function and anti-inflammatory responses (prebiotics and probiotics). However, in general really strong evidence of benefit to human health through anti-inflammatory actions is lacking for most of these dietary components. Thus, further studies addressing efficacy in humans linked to studies providing greater understanding of the mechanisms of action involved are required.
Asunto(s)
Inflamación/fisiopatología , Fenómenos Fisiológicos de la Nutrición/fisiología , Artritis Reumatoide/dietoterapia , Artritis Reumatoide/fisiopatología , Enfermedades Cardiovasculares/dietoterapia , Enfermedades Cardiovasculares/fisiopatología , Enfermedad Celíaca/dietoterapia , Enfermedad Celíaca/fisiopatología , Humanos , Inflamación/dietoterapia , Enfermedades Inflamatorias del Intestino/dietoterapia , Enfermedades Inflamatorias del Intestino/fisiopatología , Obesidad/dietoterapia , Obesidad/fisiopatología , Hipersensibilidad Respiratoria/dietoterapia , Hipersensibilidad Respiratoria/fisiopatología , Enfermedades de la Piel/dietoterapia , Enfermedades de la Piel/fisiopatologíaRESUMEN
We investigated competitive- and long-term oxidative stress during a competition season in eight top-ranked members of the Austrian Men's Alpine Ski Team. Serum total peroxides, antibody titers against oxidized LDL (oLAb) and lag time of the degradation of the fluorophore 1-palmitoyl-2-((2-(4-(6-phenyl-trans-1,3,5-hexatrienyl)phenyl)ethyl)-carbonyl)-sn-glycero-3-phosphocholine were measured, along with plasma concentrations of ascorbate, alpha- and gamma-tocopherol, beta-carotene, uric acid and the lipid status. Competitive stress was indicated through an increased post-race uric acid level (286 +/- 50 microM pre-race vs 456 +/- 77 microM post-race, P<0.001) in December. Long-term effects were already apparent in November, with the highest concentrations of total peroxides (680 +/- 458 microM H(2)O(2) equivalents vs December 47 +/- 58 microM H(2)O(2) equivalents and January 15 +/- 28 microM H(2)O(2) equivalents, P<0.001) and a concomitant decrease in oLAb titers with an antibody trough in December (439 +/- 150 mU/mL vs baseline 1036 +/- 328 mU/mL; P=0.003). In January, after recovery, they attained nearly pre-season levels of oxidative stress biomarkers. This study indicates midseason oxidative stress in top-level skiers, which was associated with the performance in these athletes.
Asunto(s)
Conducta Competitiva/fisiología , Estrés Oxidativo/fisiología , Esquí/fisiología , Adulto , Rendimiento Atlético/fisiología , Austria , Biomarcadores/sangre , Biomarcadores/orina , Humanos , Masculino , Estrés Fisiológico/fisiología , Adulto JovenRESUMEN
The regulation of cell growth and differentiation and also expression of a number of genes by retinoids are mediated by nuclear retinoid receptors (RARs and/or RXRs). In this study we investigated age-related alteration in both RAR and RXR receptor subtypes gene expression and tissue transglutaminase (tTG) activity before and after supplementation with 13-cis retinoic acid (13cRA) in human peripheral blood mononuclear cells (PBMCs). Healthy men (40) were divided in two groups according to their age (young group: 26.1+/-4.1 years and old group: 65.4+/-3.8 years). Each volunteer received 13cRA (Curacné), 0.5mg/(kgday)) during a period of 4 weeks. We have shown that RXRbeta expression was decreased significantly (p=0.0108) in PBMCs of elderly men when compared to that of young volunteers. Distribution of retinoic acid receptor subtype expression in PBMCs was found in the order: RXRbeta>RARgamma>RXRalpha>RARalpha. The tTG activity in PBMCs reflected a trend to be enhanced after 13-cis retinoic acid supplementation. In conclusion, we demonstrate a significant decrease in the expression of RXRbeta subtype of rexinoid receptors in PBMCs of healthy elderly men. Our data suggest that in healthy elderly men reduction of RXRbeta expression in PBMCs might be a common feature of physiological senescence.
Asunto(s)
Envejecimiento/genética , Suplementos Dietéticos , Isotretinoína/uso terapéutico , Leucocitos Mononucleares/efectos de los fármacos , Receptor beta X Retinoide/genética , Adulto , Factores de Edad , Anciano , Envejecimiento/sangre , Alitretinoína , Senescencia Celular/efectos de los fármacos , Senescencia Celular/genética , Regulación hacia Abajo/efectos de los fármacos , Proteínas de Unión al GTP , Humanos , Isotretinoína/sangre , Isotretinoína/farmacología , Leucocitos Mononucleares/enzimología , Leucocitos Mononucleares/metabolismo , Masculino , Persona de Mediana Edad , Proteína Glutamina Gamma Glutamiltransferasa 2 , ARN Mensajero/sangre , Receptores de Ácido Retinoico/genética , Valores de Referencia , Receptor alfa de Ácido Retinoico , Receptor alfa X Retinoide/genética , Receptor beta X Retinoide/sangre , Factores de Tiempo , Transglutaminasas/sangre , Tretinoina/sangre , Receptor de Ácido Retinoico gammaRESUMEN
BACKGROUND: In a recent pilot study, the intake of elderberry juice resulted in a significant decrease in serum cholesterol concentrations and an increase in low-density lipoprotein (LDL) stability. This study was designed to verify the preliminary results. OBJECTIVE: We investigated the impact of elderberry juice on cholesterol and triglyceride concentrations as well as antioxidant status in a cohort of young volunteers. DESIGN: Study A: The randomized, placebo-controlled trial for studying the effect of anthocyanes on lipid and antioxidant status, 34 subjects took capsules with 400 mg spray-dried powder containing 10% anthocyanes t.i.d. equivalent to 5 ml elderberry juice for 2 weeks. A subgroup of 14 subjects continued for an additional week to test for resistance to oxidation of LDL. Study B: To investigate the short-term effects on serum lipid concentrations, six subjects took a single dose of 50 ml of elderberry juice (equivalent to 10 capsules) along with a high-fat breakfast. RESULTS: In the placebo-controlled study, there was only a small, statistically not significant change in cholesterol concentrations in the elderberry group (from 199 to 190 mg/dl) compared to the placebo group (from 192 to 196 mg/dl). The resistance to copper-induced oxidation of LDL did not change within 3 weeks. In the single-dose experiment increases in postprandial triglyceride concentrations were not significantly different when the six subjects were investigated with and without elderberry juice. CONCLUSIONS: Elderberry spray-dried extract at a low dose exerts a minor effect on serum lipids and antioxidative capacity. Higher, but nutritionally relevant doses might significantly reduce postprandial serum lipids.
Asunto(s)
Antioxidantes/farmacología , Bebidas , Ayuno/sangre , Lípidos/sangre , Lipoproteínas LDL/sangre , Periodo Posprandial/fisiología , Sambucus/metabolismo , Antioxidantes/administración & dosificación , Ácido Ascórbico/sangre , Colesterol/sangre , Cromatografía Líquida de Alta Presión , Método Doble Ciego , Femenino , Humanos , Masculino , Oxidación-ReducciónRESUMEN
BACKGROUND: Oxidative stress occurs during strenuous physical exercise, perhaps as a result of increased consumption of oxygen. MATERIALS AND METHODS: In this study, different markers of oxidative stress were determined in eight national league American football players. Before (March) and at three time-points during the competition season (May, June, July) serum total peroxide concentrations, auto-antibody titres against oxidized low-density lipoprotein (oLab), and lag time of reactive oxygen species-induced degradation of the fluorophore 1-palmitoyl-2-((2-(4-(6-phenyl-trans-1,3,5-hexatrienyl)phenyl)ethyl)- carbonyl)-sn-glycero-3-phosphocholine (DPHPC) were measured along with serum ascorbate, alpha- and gamma-tocopherol, and beta-carotene concentrations. RESULTS: Before the competition season, serum antioxidant concentrations were within the lower normal range; ascorbate concentrations increased significantly during the competition period (P < 0.05). Serum peroxide concentrations were within the normal range and increased significantly during the competition period (P < 0.05); in four of the eight subjects the increase was several times the baseline values, while four athletes did not show any increase. The oLab titres increased significantly at the mid-competition period time-point (P < 0.01), but levelled off thereafter. DISCUSSION: Given that it could not be predicted from the baseline oxidative stress and antioxidant status which subject would respond to strenuous exercise with an increase in oxidative stress status, it is concluded that oxidative stress should be monitored in all athletes.
Asunto(s)
Antioxidantes/análisis , Fútbol Americano/fisiología , Peroxidación de Lípido , Resistencia Física , Adulto , Análisis de Varianza , Ácido Ascórbico/sangre , Autoanticuerpos/sangre , Biomarcadores/sangre , Humanos , Lipoproteínas LDL/inmunología , Masculino , Estrés Oxidativo , Peróxidos/sangreRESUMEN
Does cigarette smoking increase vitamin E utilization in vivo? A trial was carried out in 6 smokers and 5 nonsmokers of comparable ages and serum lipids. Subjects consumed 75 mg each d(3)-RRR and d(6)-all rac-alpha-tocopheryl acetates (natural and synthetic vitamin E, respectively) daily for 7 d with a standardized breakfast. Fasting blood samples were drawn on days -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 14, 21 (negative days indicate supplementation). In both groups, plasma d(3)-alpha-tocopherol concentrations were approximately double of d(6)-alpha-tocopherol. At day 0, the %d(3) alpha-tocopherols (d(3)-alpha-tocopherol/total-alpha-tocopherol x 100) were similar in both smokers and nonsmokers. Subsequently, there was a trend toward a faster exponential disappearance of the plasma %d(3) alpha-tocopherol in smokers compared with nonsmokers (0.30 +/- 0.04 compared with 0.24 +/- 0.05, p =.0565). The calculated %d(3) half-lives were 55.6 +/- 7.4 h in smokers and 72.1 +/- 17.3 h in nonsmokers (p =.0630). By day 21, the %d(3) in smokers had decreased to 1.4% +/- 0.3% while it was 2.2% +/- 0.7% (p =.0418) in the nonsmokers. These data suggest that smoking increases plasma vitamin E disappearance, but further studies are needed to confirm this finding and to assess its cause.
Asunto(s)
Fumar/sangre , Vitamina E/farmacocinética , alfa-Tocoferol/análogos & derivados , Adulto , Colesterol/sangre , Deuterio , Humanos , Cinética , Malondialdehído/sangre , Tocoferoles , Triglicéridos/sangre , alfa-Tocoferol/administración & dosificación , alfa-Tocoferol/sangre , alfa-Tocoferol/farmacocinéticaRESUMEN
BACKGROUND: Chronic renal failure is associated with accelerated atherosclerosis and a high incidence of cardiovascular disease. Oxidative modification of low-density lipoprotein (LDL) is considered a key event in atherogenesis. METHODS: We studied the ex vivo oxidizability of LDL exposed to Cu2+ ions (lag time, rate of propagation, maximum conjugated diene formation) and its relationship with LDL density, fatty acids, and antioxidants, along with plasma malondialdehyde (MDA) and autoantibodies against Cu2+-, MDA-, and hypochlorous acid-modified LDL and plasma antioxidants in 17 continuous ambulatory peritoneal dialysis (CAPD) patients and 21 healthy control subjects. RESULTS: LDL alpha- and gamma-tocopherol and total polyunsaturated fatty acid (PUFA) concentrations were significantly higher in the CAPD patients. LDL density was shifted to small, dense LDL. LDL oxidizability was comparable to that of healthy subjects. Lag time correlated positively with LDL alpha-tocopherol and inversely with both total PUFA concentrations and density; the rate of oxidation and LDL density correlated positively with total PUFA and total fatty acid concentrations, respectively. Ratios of autoantibody titers against oxidized to native LDL did not differ between the two groups. While plasma alpha- and gamma-tocopherol concentrations and tocopherol to cholesterol ratios were significantly higher, vitamin C concentrations were very low in the CAPD patients. MDA concentrations were 1.7 times higher than in healthy subjects. CONCLUSIONS: (1) Ex vivo LDL oxidizability is normal in CAPD patients as a result of efficient protection by LDL-associated lipophilic antioxidants, although the LDL composition is altered toward high oxidizability; and (2) the plasma antioxidant screen is insufficient due to impaired vitamin C status.
Asunto(s)
Peroxidación de Lípido , Lipoproteínas LDL/sangre , Diálisis Peritoneal Ambulatoria Continua/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Antioxidantes/metabolismo , Autoanticuerpos/sangre , Estudios de Casos y Controles , Ácidos Grasos/sangre , Ácidos Grasos Insaturados/sangre , Femenino , Humanos , Técnicas In Vitro , Fallo Renal Crónico/sangre , Fallo Renal Crónico/terapia , Lipoproteínas LDL/inmunología , Masculino , Malondialdehído/sangre , Persona de Mediana Edad , Oxidación-Reducción , Estrés OxidativoRESUMEN
Among the nutritional factors contributing to maintain health during ageing, fat-soluble vitamins (FSV) are crucial to protect against free radical-generated degenerative processes or impaired efficiency of the immune system. However, no sound scientific evidence is able to confirm specific dietary needs in vitamin A, vitamin E and carotenoids for the healthy elderly. VITAGE project aims at providing such evidence by undertaking studies on male volunteers from 3 European countries, aged between 20-75 years. Biomarkers and variables related to status, metabolism and functions will be measured either in steady-state conditions, or during dietary depletion and repletion in FSV. Original, yet already developed, methodologies will provide clear information about the physiological characteristics of vitamin A, vitamin E and carotenoids. Simultaneously, marketing opportunities for FSV-enriched dietetic foods, specifically designed for the elderly will be determined. The scientific and economical evidence obtained in this project will provide the basis to implement a EU nutritional policy towards the elderly and to develop a new sector of dietetic food products.
Asunto(s)
Envejecimiento/fisiología , Carotenoides/metabolismo , Vitamina A/metabolismo , Vitamina E/metabolismo , Adulto , Anciano , Envejecimiento/metabolismo , Unión Europea , Humanos , Masculino , Persona de Mediana Edad , Política Nutricional , Necesidades Nutricionales , Estado NutricionalAsunto(s)
Antioxidantes/metabolismo , Antioxidantes/uso terapéutico , Enfermedades Carenciales/dietoterapia , Suplementos Dietéticos , Política Nutricional , Adyuvantes Inmunológicos/metabolismo , Adyuvantes Inmunológicos/uso terapéutico , Antiinflamatorios/metabolismo , Antiinflamatorios/uso terapéutico , Antioxidantes/administración & dosificación , Ácido Ascórbico/metabolismo , Ácido Ascórbico/uso terapéutico , Quimioterapia Adyuvante , Glutatión/metabolismo , Glutatión/uso terapéutico , Humanos , Prevención Primaria , Vitamina E/metabolismo , Vitamina E/uso terapéuticoRESUMEN
Recent studies have focused on the current dietary intake of cystic fibrosis patients, the impact of nutritional support on both the nutritional status and clinical outcome variables, and the effects on the nutritional status of antibiotic therapy and surgical treatment of meconium ileus. In addition to weight and height, skinfold measurements, bioelectrical impedance analysis and dual energy X-ray absorptiometry have been employed for the determination of nutritional status. A proton pump inhibitor has been used successfully along with pancreatic enzymes for the improvement of fat absorption. Attention has been paid to resting energy expenditure during pulmonary exacerbations, to vitamin K function in bone mineralization and to risk factors for low bone mineral density in cystic fibrosis. The relationships between glutathione and nutritional status have been studied, along with possible interactions with albumin, a potent antioxidant. Finally, a beneficial effect of docosahexaenoic acid on cystic fibrosis pathology has been suggested, but this requires further critical evaluation.
Asunto(s)
Fibrosis Quística , Micronutrientes , Estado Nutricional , Enfermedades Óseas , Dieta , Ácidos Grasos Esenciales , Humanos , Evaluación NutricionalRESUMEN
Oxidant stress induced by hydrophobic bile acids has been implicated in the pathogenesis of liver injury in cholestatic liver disorders. We evaluated the effect of idebenone, a coenzyme Q analogue, on taurochenodeoxycholic acid (TCDC)-induced cell injury and oxidant stress in isolated rat hepatocytes and on glycochenodeoxycholic acid (GCDC)-induced generation of hydroperoxides in fresh hepatic mitochondria. Isolated rat hepatocytes in suspension under 9% oxygen atmosphere were preincubated with 0, 50, and 100 micromol/l idebenone for 30 min and then exposed to 1000 micromol/l TCDC for 4 h. LDH release (cell injury) and thiobarbituric acid reactive substances (measure of lipid peroxidation) increased after TCDC exposure but were markedly suppressed by idebenone pretreatment. In a second set of experiments, the addition of 100 micromol/l idebenone up to 3 h after hepatocytes were exposed to 1000 micromol/l TCDC resulted in abrogation of subsequent cell injury and markedly reduced oxidant damage to hepatocytes. Chenodeoxycholic acid concentrations increased to 5.15 nmol/10(6) cells after 2 h and to 7.05 after 4 h of incubation of hepatocytes with 1000 micromol/l TCDC, and did not differ in the presence of idebenone. In freshly isolated rat hepatic mitochondria, when respiration was stimulated by succinate, 10 micromol/l idebenone abrogated the generation of hydroperoxides during a 90-minute exposure to 400 micromol/l GCDC. These data demonstrate that idebenone functions as a potent protective hepatocyte antioxidant during hydrophobic bile acid toxicity, perhaps by reducing generation of oxygen free radicals in mitochondria.
Asunto(s)
Antioxidantes/farmacología , Benzoquinonas/farmacología , Ácidos y Sales Biliares/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas , Hígado/efectos de los fármacos , Mitocondrias Hepáticas/efectos de los fármacos , Animales , Ácidos y Sales Biliares/metabolismo , Ácido Glicoquenodesoxicólico/toxicidad , L-Lactato Deshidrogenasa/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Hígado/metabolismo , Masculino , Mitocondrias Hepáticas/metabolismo , Estrés Oxidativo , Ratas , Ratas Sprague-Dawley , Ácido Succínico/farmacología , Ácido Tauroquenodesoxicólico/toxicidad , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismo , Ubiquinona/análogos & derivadosRESUMEN
To substitute for exocrine pancreatic insufficiency, patients with cystic fibrosis (CF) take pancreatic enzymes (PE) originating from porcine pancreas. Five different pancreatic enzyme preparations used by our patients contained 0.5-1.4 microg selenium per g tablet. In patients taking PE in doses that were gradually increased to improve fat absorption during a 48-month period, the effects of PE dose on erythrocyte selenium-dependent glutathione peroxidase (SeGSH-Px) activities and plasma selenium concentrations were studied. At baseline, erythrocyte SeGSH-Px activities were significantly lower in patients (p=.01), while plasma selenium concentrations did not differ between patients and healthy subjects. When PE dose and, consequently, selenium intake from PE was increased, erythrocyte SeGSH-Px activities (p < .001) and plasma selenium concentrations (p=.02) increased. Changes in SeGSH-Px activities during the initial 8 months correlated with those in selenium intake from PE (r=0.67, p < .001). Plasma selenium concentrations plateaued at 12 months and erythrocyte SeGSH-Px activities did so at 36 months, when patients had reached SeGSH-Px activities similar to those of healthy subjects. At 48 months, patients took an average lipase dose of 17400 U x kg(-1) x d(-1) and selenium dose from PE of 0.53 microg x kg(-1) x d(-1). We conclude that selenium content of PE preparations has a significant effect on SeGSH-Px activity in patients with CF. This form of selenium supply needs to be taken into account when selenium supplements are given to patients with CF.
Asunto(s)
Fibrosis Quística/tratamiento farmacológico , Enzimas/farmacología , Eritrocitos/efectos de los fármacos , Eritrocitos/enzimología , Glutatión Peroxidasa/efectos de los fármacos , Glutatión Peroxidasa/metabolismo , Extractos Pancreáticos/farmacología , Selenio/sangre , Administración Oral , Adolescente , Adulto , Niño , Preescolar , Estudios Transversales , Fibrosis Quística/sangre , Fibrosis Quística/metabolismo , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Activación Enzimática/efectos de los fármacos , Eritrocitos/metabolismo , Femenino , Glutatión Peroxidasa/análisis , Humanos , Lactante , Lipasa/administración & dosificación , Lipasa/química , Lipasa/farmacología , Estudios Longitudinales , Masculino , Extractos Pancreáticos/administración & dosificación , Extractos Pancreáticos/química , Pancreatina/administración & dosificación , Pancreatina/química , Pancreatina/farmacología , Pancrelipasa , Selenio/análisisRESUMEN
Vitamin C status and possible associations with the disease process in cystic fibrosis (CF) patients were investigated. Plasma vitamin C concentrations in patients from two different mid-European populations (Swiss, n = 62; Austrian, n = 60) taking no or low-dose vitamin C from multivitamin supplements did not differ from each other or from control subjects (n = 34). Vitamin C concentrations decreased with age (5.05 mumol.L-1, y-1). When followed up for 12 mo, patients had the highest plasma vitamin C concentrations in February and the lowest in May and August (P < 0.01); the decrease in vitamin C was accompanied by increases in plasma malondialdehyde (P < 0.001) and tumor necrosis factor alpha concentrations (P < 0.01). During supplementation with vitamin E for 2 mo or beta-carotene for 12 mo vitamin C concentrations did not change. They correlated inversely with white blood cell count (r = -0.36, P = 0.008), bands (r = -0.36, P = 0.02), alpha 1-acid glycoprotein (r = -0.45, P = 0.002), interleukin 6 (r = -0.46, P = 0.0006), and neutrophil elastase/alpha 1-proteinase inhibitor complexes (r = -0.34, P = 0.02). In patients with vitamin C concentrations < 40 mumol/L, all indexes of inflammation were relatively high, whereas those with concentrations > 80 mumol/L (upper quartile of control subjects) showed clearly lower values. These results are consistent with the hypothesis that by scavenging oxygen free radicals vitamin C interacts with an inflammation-amplifying cycle of activation of alveolar macrophages and neutrophils, release of proinflammatory cytokines and oxygen free radicals, and inactivation of antiproteases.
Asunto(s)
Ácido Ascórbico/sangre , Fibrosis Quística/sangre , Enfermedades Pulmonares/sangre , Adolescente , Adulto , Niño , Preescolar , Estudios de Cohortes , Fibrosis Quística/etiología , Fibrosis Quística/fisiopatología , Citocinas/metabolismo , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Lactante , Inflamación/sangre , Inflamación/etiología , Inflamación/fisiopatología , Interleucina-6/sangre , Elastasa de Leucocito/sangre , Peroxidación de Lípido/fisiología , Enfermedades Pulmonares/etiología , Enfermedades Pulmonares/fisiopatología , Masculino , Malondialdehído/sangre , Estado Nutricional , Orosomucoide/análisis , Orosomucoide/metabolismo , Estaciones del Año , Factor de Necrosis Tumoral alfa/análisis , Factor de Necrosis Tumoral alfa/metabolismo , Vitamina E/administración & dosificación , Vitamina E/farmacología , beta Caroteno/administración & dosificación , beta Caroteno/sangre , beta Caroteno/farmacologíaRESUMEN
In a cross-sectional survey, plasma concentrations of alpha- and gamma-tocopherol, alpha- and beta-carotene (cis and trans isomers), lycopene, and retinol were determined by reversed-phase HPLC, and ratios of plasma alpha-tocopherol to cholesterol were calculated in 208 Swiss individuals ages 0.4-38.7 years. The influence of age, sex, and season of sampling was studied. Age was a significant predictor of all plasma concentrations except alpha-carotene. No sex-related differences were observed. Season of sampling affected alpha-tocopherol and retinol (higher in winter) and gamma-tocopherol and cholesterol concentrations (higher in winter and spring than in the other seasons). After correction for seasonal influences, age differences were 0.24 micromol/L per year for alpha-tocopherol, 0.04 micromol/L per year for retinol, and 0.04 micromol/L per year for cholesterol concentrations; ratios of plasma alpha-tocopherol to cholesterol were not affected by age. We constructed age-specific reference intervals from the regression line and a multiple of the standard deviation. Separate regression equations are presented for seasons with low and high values.
Asunto(s)
Carotenoides/sangre , Estaciones del Año , Vitamina A/sangre , Vitamina E/sangre , Adolescente , Adulto , Niño , Preescolar , Colesterol/sangre , Cromatografía Líquida de Alta Presión , Femenino , Humanos , Lactante , Licopeno , Masculino , Valores de Referencia , Suiza , beta Caroteno/sangreRESUMEN
LDL resistance to oxidation is characterized by the lag time that precedes the rapid generation of conjugated dienes in copper-induced oxidation. Lag time (y) is described by the equation y = kx + a, where k is the efficacy constant of alpha-tocopherol (alpha-TOH), x the alpha-TOH content of LDL, and a the alpha-TOH-independent variable, all of which show considerable between-subject variability. To answer the question of whether loading of LDL with Trolox can substitute for the more timeconsuming loading with RRR-alpha-TOH in large scale studies focusing on determination of k and a values, LDL from 15 healthy subjects was loaded in vitro with 0-50 mol Trolox/mol LDL or 0-250 mM RRR-alpha-TOH. In addition, five of these subjects were supplemented in vivo with 800-1200 IU/d RRR-alpha-TOH for 17 days and k and a were determined. The ratios k(Trolox):k(alpha-TOH) and alpha(Trolox):a(alpha-TOH) were calculated. The k(Trolox) was only slightly higher than k(alpha-TOH), in contrast to alpha(Trolox), which was almost twice as high as a(alpha-TOH), indicating that, in the case of Trolox, a includes the contribution of alpha-TOH to the lag time. In the case of alpha-TOH, a includes only the additional antioxidants that occur naturally in LDL. The ratios k(Trolox):k(alpha-TOH) and alpha(Trolox):a(alpha-TOH) showed little variability, both between subjects and between in vitro and in vivo experiments. A close correlation was found between k(alpha-TOH) and a(alpha0TOH), calculated using this ratio, and k(alpha-TOH) and a(alpha-TOH), obtained in our experiments. We conclude that from this ratio, k(alpha-TOH) and a(alpha-TOH) can be reliably calculated when k(Trolox) and a(Trolox) are determined experimentally, thus allowing us to obtain k and a values in a more convenient way.
Asunto(s)
Cromanos/metabolismo , Lipoproteínas LDL/análisis , Lipoproteínas LDL/metabolismo , Vitamina E/metabolismo , Adulto , Antioxidantes/metabolismo , Cobre/farmacología , Femenino , Humanos , Cinética , Masculino , Oxidación-Reducción , Análisis de Regresión , Espectrofotometría , Vitamina E/administración & dosificación , Vitamina E/análogos & derivadosRESUMEN
In 59 healthy human subjects (37 male and 22 female) the concentrations of the lipid-soluble antioxidants alpha- and gamma-tocopherol, alpha- and beta-carotene, lycopene, cryptoxanthin, canthaxanthin, and lutein + zeaxanthin were determined in plasma (mumol/L) and in isolated low density lipoproteins (LDL) (mumol/mmol cholesterol). Plasma alpha-tocopherol concentrations were significantly correlated with plasma total cholesterol concentrations (r2 = 0.51, P < 0.0001) yet not with the LDL alpha-tocopherol content (r2 = 0.05, ns). Plasma gamma-tocopherol concentrations were weakly correlated with plasma total cholesterol (r2 = 0.12, P < 0.003) and both absolute and cholesterol standardized plasma gamma-tocopherol concentrations correlated strongly with the LDL gamma-tocopherol content (r2 = 0.58 and r2 = 0.72, respectively). In contrast, carotenoid concentrations did not correlate with cholesterol concentrations, but their LDL content correlated significantly with the respective plasma concentrations (r2 = 0.67 to 0.92, all P < 0.0001). In a subgroup of study subjects (n = 13) the distribution of vitamin E and carotenoids among LDL was calculated. The proportion of plasma alpha- and gamma-tocopherol found in LDL was 48 +/- 7 (range, 36-61%) and 41 +/- 7%, respectively, suggesting that LDL was in most of these subjects not the main carrier for these antioxidants. The lipophilic carotenoids, however, were predominantly carried by LDL (e.g., beta-carotene: 87 +/- 10%), whereas the proportion of the more polar ones carried by LDL was much smaller (e.g., lutein + zeaxanthin: 36 +/- 6%). The results of this study show that plasma alpha-tocopherol concentrations are not predictive for the alpha-tocopherol content of LDL in nonsupplemented individuals. This finding could have implications in interpreting the cause of the inverse relationship between plasma alpha-tocopherol and risk of atherosclerosis.