RESUMO
Calcineurin inhibitors post-renal transplantation are recognized to cause tubulopathies in the form of hyponatremia, hyperkalemia, and acidosis. Sodium supplementation may be required, increasing medication burden and potentially resulting in poor compliance. Fludrocortisone has been beneficial in addressing tubulopathies in adult studies, with limited paediatric data available. A retrospective review of data from an electronic renal database from December 2014 to January 2016 was carried out. Forty-seven post-transplant patients were reviewed with 23 (49%) patients on sodium chloride or bicarbonate. Nine patients, aged 8.3 years (range 4.9-16.4), commenced fludrocortisone 22 months (range 1-80) after transplant and were followed up for 9 months (range 2-20). All patients stopped sodium bicarbonate; all had a reduction or no increase in total daily doses of sodium chloride. Potassium levels were significantly lower on fludrocortisone, 5.2 vs 4.5 mmol/L, P = .04. No difference was noted in renal function (eGFR 77.8 vs 81.7 mL/min/1.73 m2 , P = .45) and no significant increase in systolic blood pressure (z-scores 0.99 vs 0.85, P = .92). No side effects secondary to treatment with fludrocortisone were reported. A significant proportion of renal transplant patients were on sodium supplementation and fludrocortisone reduced sodium supplementation without significant effects on renal function or blood pressure. Fludrocortisone appears to be safe and effective for tubulopathies in children post-transplantation.
Assuntos
Anti-Inflamatórios/uso terapêutico , Fludrocortisona/uso terapêutico , Nefropatias/tratamento farmacológico , Transplante de Rim , Túbulos Renais/fisiopatologia , Complicações Pós-Operatórias/tratamento farmacológico , Adolescente , Criança , Pré-Escolar , Esquema de Medicação , Feminino , Seguimentos , Humanos , Nefropatias/etiologia , Nefropatias/fisiopatologia , Masculino , Complicações Pós-Operatórias/fisiopatologia , Estudos RetrospectivosRESUMO
Pharmacogenetics-guided warfarin dosing is an alternative to standard clinical algorithms and new oral anticoagulants for patients with nonvalvular atrial fibrillation. However, clinical evidence for pharmacogenetics-guided warfarin dosing is limited to intermediary outcomes, and consequently, there is a lack of information on the cost-effectiveness of anticoagulation treatment options. A clinical trial simulation of S-warfarin was used to predict times within therapeutic range for different dosing algorithms. Relative risks of clinical events, obtained from a meta-analysis of trials linking times within therapeutic range with outcomes, served as inputs to an economic analysis. Neither dabigatran nor rivaroxaban were cost-effective options. Along the cost-effectiveness frontier, in relation to clinically dosed warfarin, pharmacogenetics-guided warfarin and apixaban had incremental cost-effectiveness ratios of £13,226 and £20,671 per quality-adjusted life year gained, respectively. On the basis of our simulations, apixaban appears to be the most cost-effective treatment.
Assuntos
Anticoagulantes/economia , Fibrilação Atrial/tratamento farmacológico , Farmacogenética/economia , Varfarina/economia , Algoritmos , Anticoagulantes/uso terapêutico , Fibrilação Atrial/complicações , Fibrilação Atrial/economia , Benzimidazóis/economia , Benzimidazóis/uso terapêutico , Análise Custo-Benefício , Dabigatrana , Custos de Medicamentos , Cálculos da Dosagem de Medicamento , Humanos , Morfolinas/economia , Morfolinas/uso terapêutico , Farmacogenética/métodos , Pirazóis/economia , Pirazóis/uso terapêutico , Piridonas/economia , Piridonas/uso terapêutico , Anos de Vida Ajustados por Qualidade de Vida , Rivaroxabana , Acidente Vascular Cerebral/prevenção & controle , Tiofenos/economia , Tiofenos/uso terapêutico , Varfarina/administração & dosagem , Varfarina/uso terapêutico , beta-Alanina/análogos & derivados , beta-Alanina/economia , beta-Alanina/uso terapêuticoRESUMO
Alternative anticoagulants to warfarin (dabigatran, rivaroxaban, and apixaban) are becoming available for the prevention of thromboembolic stroke in atrial fibrillation (AF), but there is a lack of information on their comparative effectiveness. Using a discrete event simulation method adopting a lifetime horizon of analysis, we made an indirect comparison of the RE-LY, ROCKET-AF, and ARISTOTLE trial results for AF patients in the US population. Over a lifetime, apixaban, dabigatran, and rivaroxaban accrued 0.130 (95% central range (CR) -0.030 to 0.264), 0.106 (95% CR -0.048 to 0.248), and 0.095 (95% CR -0.052 to 0.242) more quality-adjusted life-years (QALYs), respectively, than warfarin, with apixaban having a 55% probability of accruing the highest total QALYs. In the absence of a definitive trial, and acknowledging the limitations of an indirect comparison, the available evidence suggests apixaban to be the most effective anticoagulant.
Assuntos
Antitrombinas/uso terapêutico , Fibrilação Atrial/tratamento farmacológico , Simulação por Computador , Fatores Etários , Idoso , Antitrombinas/administração & dosagem , Antitrombinas/efeitos adversos , Benzimidazóis/uso terapêutico , Doenças Cardiovasculares/epidemiologia , Comorbidade , Dabigatrana , Feminino , Hemorragia/induzido quimicamente , Humanos , Masculino , Morfolinas/uso terapêutico , Pirazóis/uso terapêutico , Piridonas/uso terapêutico , Anos de Vida Ajustados por Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Rivaroxabana , Tiofenos/uso terapêutico , Fatores de Tempo , Varfarina/uso terapêutico , beta-Alanina/análogos & derivados , beta-Alanina/uso terapêuticoRESUMO
Vitamin D is now known to be of physiological importance outside of bone health and calcium homeostasis, and there is mounting evidence that it plays a beneficial role in the prevention and/or treatment of a wide range of diseases. In this brief review the known effects of vitamin D on immune function are described in relation to respiratory health. Vitamin D appears capable of inhibiting pulmonary inflammatory responses while enhancing innate defence mechanisms against respiratory pathogens. Population-based studies showing an association between circulating vitamin D levels and lung function provide strong justification for randomized controlled clinical trials of vitamin D supplementation in patients with respiratory diseases to assess both efficacy and optimal dosage.
Assuntos
Fatores Imunológicos/fisiologia , Vitamina D/fisiologia , Asma/tratamento farmacológico , Asma/fisiopatologia , Suplementos Nutricionais , Humanos , Fatores Imunológicos/uso terapêutico , Pulmão/metabolismo , Pulmão/fisiopatologia , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Testes de Função Respiratória , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/fisiopatologia , Vitamina D/uso terapêuticoRESUMO
AIM: Gaucher disease type 1 (GD-1) is the most prevalent lysosomal storage disorder and frequently causes osteopenia and osteoporosis. Adequate vitamin D levels are essential for bone health. The present study retrospectively analyzed 25-hydroxyvitamin D (25[OH]D) in outpatients with GD-1. PATIENTS AND METHODS: Sixty GD-1 patients living at home and with residence in southern or central England (34 men, 26 women), aged 17-85 years (mean 45.0 years) were seen at routine follow-up visits (range: 1-9, mean: 4.4) between January 2003 and July 2007. Overall, 264 blood samples, collected at different seasons of the year, were present for laboratory testing. The retrospective interpretation of vitamin D deficiency was based on different cut-off levels of 25(OH)D (<25 nmol/L, <50 nmol/L, <80 nmol/L) and the seasons of the year. Vitamin D sufficiency was defined as 25(OH)D >80 nmol/L. RESULTS: The mean+/-SD of 25(OH)D was 58.2+/-30.3. Degrees of vitamin D deficiency (<25 nmol/L, <50 nmol/L, <80 nmol/L) were present in 9.1%, 44.3%, 83.0%, vitamin D sufficiency (>80 nmol/L) in only 17.0%, respectively. A significant seasonal variation of 25(OH)D was present. Results of vitamin D deficiency for December-May were 15.7%, 63.8%, 92.9%, and for June-November 2.9%, 26.3%, 73.7%. The 25(OH)D values representing the seasonal nadir observed during the season December-May showed a significant correlation with T-scores and Z-scores of the lumbar spine and hip. Parathyroid hormone and 25(OH)D were inversely correlated. CONCLUSIONS: Vitamin D deficiency is frequent among GD-1 patients. To optimize treatment of GD-1 vitamin D supplementation should be recommended.
Assuntos
Densidade Óssea , Doença de Gaucher/fisiopatologia , Deficiência de Vitamina D/epidemiologia , Vitamina D/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Inglaterra/epidemiologia , Feminino , Doença de Gaucher/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Estações do Ano , Deficiência de Vitamina D/sangue , Adulto JovemRESUMO
Bone manifestations are frequent in Gaucher disease (GD), the most prevalent lysosomal storage disorder. Currently, therapy with enzyme replacement (ERT) or substrate reduction (SRT) is available. We investigated changes of laboratory parameters associated with bone metabolism in GD patients switching from ERT to SRT. Seven GD patients consecutively treated with ERT and SRT were studied. All patients had different degrees of bone involvement. Laboratory results were acquired at the time of change from ERT to SRT (0 months) and while on SRT (6 months, 12-18 months). Markers of GD activity remained stable or showed statistically insignificant increases. Six patients had stable skeletal manifestations and reported no bone-associated symptoms. One patient presented progressive bone manifestations on magnetic resonance imaging and experienced increasing bone pain. Osteocalcin, alkaline phosphatase, and C-terminal telopeptide of collagen I were initially within the lower part of the normal range and decreased during SRT (alkaline phosphatase P = 0.0169, osteocalcin nonsignificant, C-terminal telopeptide of collagen I nonsignificant). Tartrate-resistant acid phosphatase 5b was initially normal or slightly increased, and macrophage colony-stimulating factor was within the normal lower range; both parameters remained stable. Interleukin-6 was elevated only in the patient with progressive bone disease. Macrophage inflammatory protein 1alpha (MIP-1alpha) was elevated without change after switching to SRT. MIP-1beta was within the normal range, and no values were above 85 ng/mL, indicative of active skeletal disease. From a clinical and metabolic point of view, most skeletal manifestations and bone-associated laboratory parameters remain stable after switch from ERT to SRT.
Assuntos
1-Desoxinojirimicina/análogos & derivados , Osso e Ossos/metabolismo , Inibidores Enzimáticos/uso terapêutico , Doença de Gaucher/tratamento farmacológico , Doença de Gaucher/metabolismo , Glucosilceramidase/uso terapêutico , 1-Desoxinojirimicina/uso terapêutico , Absorciometria de Fóton , Adulto , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea/efeitos dos fármacos , Remodelação Óssea/efeitos dos fármacos , Osso e Ossos/efeitos dos fármacos , Feminino , Doença de Gaucher/fisiopatologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-IdadeRESUMO
We report here the results of 24 months' treatment with oral miglustat of a patient with mild-to-moderate Gaucher's disease (GD) and Parkinsonism. The patient's progressive Parkinsonian tremor, in addition to restricted vascular access, necessitated switching treatment for GD from intravenously infused enzyme replacement therapy (ERT) that had been administered for the previous 7 years. With control of haematological parameters and markers of GD activity improved or maintained and no notable adverse effects, miglustat treatment proved an effective and well-tolerated therapeutic alternative to ERT. Oral miglustat should be considered for the treatment of patients with type I GD and concurrent movement disorders who are unsuitable for ERT.
Assuntos
1-Desoxinojirimicina/análogos & derivados , Inibidores Enzimáticos/administração & dosagem , Doença de Gaucher/tratamento farmacológico , Doença de Parkinson/tratamento farmacológico , 1-Desoxinojirimicina/administração & dosagem , Administração Oral , Idoso , Seguimentos , Doença de Gaucher/sangue , Doença de Gaucher/complicações , Hexosaminidases/sangue , Humanos , Masculino , Doença de Parkinson/sangue , Doença de Parkinson/complicações , Peptidil Dipeptidase A/sangueRESUMO
OBJECTIVE: We hypothesized that acute hyperglycemia (an independent cardiovascular risk factor) increases the expression of proatherogenic leukocyte adhesion molecule in type 2 diabetes and controls and that the expression of these adhesion molecules would be antioxidant sensitive. METHODS AND RESULTS: Twenty-three type 2 diabetes patients and 13 control patients underwent two oral glucose tolerance tests 14 days apart and took placebo or 800 IU daily of oral alpha tocopherol between tests. Monocyte and neutrophil expression of adhesion molecules Mac-1, LFA-1 and 3, ICAM-1, and VLA-4 were measured at 0, 120, and 240 minutes by using laser flow cytometry. Baseline adhesion molecule expression did not differ between groups, but there was a rapid, highly significant increase (P<0.0001) in the intensity of monocyte Mac-1 expression after a glucose load in both groups. Alpha-tocopherol supplementation reduced only Mac-1 expression in the diabetes group (P=0.03). CONCLUSIONS: Acute glycemic excursions of any degree cause highly significant, rapid increases in monocyte Mac-1 expression in type 2 diabetes patients and controls. Mac-1 mediates leukocyte vascular infiltration and is prothrombotic. These data suggest a mechanism for the link between glycemic excursions and increased vascular event rates.
Assuntos
Antioxidantes/uso terapêutico , Moléculas de Adesão Celular/biossíntese , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hiperglicemia/sangue , Monócitos/metabolismo , Neutrófilos/metabolismo , Doença Aguda , Administração Oral , Adulto , Idoso , Antioxidantes/administração & dosagem , Antioxidantes/metabolismo , Antígenos CD58/biossíntese , Antígenos CD58/sangue , Moléculas de Adesão Celular/sangue , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Feminino , Teste de Tolerância a Glucose , Humanos , Hiperglicemia/complicações , Integrina alfa4beta1 , Integrinas/biossíntese , Integrinas/sangue , Molécula 1 de Adesão Intercelular/biossíntese , Molécula 1 de Adesão Intercelular/sangue , Interleucina-6/sangue , Antígeno-1 Associado à Função Linfocitária/biossíntese , Antígeno-1 Associado à Função Linfocitária/sangue , Antígeno de Macrófago 1/biossíntese , Antígeno de Macrófago 1/sangue , Masculino , Pessoa de Meia-Idade , Monócitos/patologia , Neutrófilos/patologia , Receptores de Retorno de Linfócitos/biossíntese , Receptores de Retorno de Linfócitos/sangue , Solubilidade , Fator de Necrose Tumoral alfa/metabolismo , alfa-Tocoferol/administração & dosagem , alfa-Tocoferol/sangue , alfa-Tocoferol/uso terapêuticoRESUMO
The colorful group of compounds known as carotenoids are present in many plants, where they provide photoprotection and act as accessory pigments in photosynthesis. Many epidemiologic studies have shown strong associations between diets rich in carotenoids and a reduced incidence of many forms of cancer, and that finding led to the suggestion that the antioxidant properties of those compounds might help protect immune cells from oxidative damage, thus enhancing their ability to detect and eliminate tumor cells. Since the early 1980s, there have been reports supporting that hypothesis. However, more recently, after large prospective studies did not show protective effects of beta-carotene supplementation, more attention has been given to studies defining optimal levels of intake that can be achieved within a well-balanced diet. The latest intervention studies have suggested that, in well-nourished, healthy individuals, a moderate level of carotenoid supplementation is neither beneficial nor harmful. However, supplementation might be appropriate in undernourished or less healthy individuals, particularly if they are elderly. Future studies comparing supplements with real foodstuffs, combined with postgenomic technologies, will help define optimal intakes for different sectors of the population.
Assuntos
Antioxidantes/administração & dosagem , Carotenoides/administração & dosagem , Imunidade/efeitos dos fármacos , Neoplasias/prevenção & controle , Antioxidantes/uso terapêutico , Carotenoides/uso terapêutico , Suplementos Nutricionais , Humanos , Sistema Imunitário/efeitos dos fármacos , Sistema Imunitário/fisiologia , Imunidade/fisiologia , Neoplasias/imunologia , Oxirredução , Estresse Oxidativo , beta Caroteno/administração & dosagem , beta Caroteno/uso terapêuticoRESUMO
In vivo supplementation studies of the antioxidant alpha-tocopherol in human Type II diabetes have used surrogate, rather than direct, markers of oxidative damage/antioxidant protection and have used higher doses of alpha-tocopherol than used in coronary secondary prevention trials. We tested the hypothesis that oral alpha-tocopherol in a dosage regimen used in secondary prevention trials would reduce directly observed oxidatively induced single-strand breaks in lymphocyte DNA in Type II diabetes. We studied 40 people with Type II diabetes and 30 controls in a randomized, double-blind, placebo-controlled trial of 400 i.u. of oral alpha-tocopherol daily for 8 weeks. Lymphocyte DNA single-strand breaks and low-density lipoprotein (LDL) particle size and oxidizability were measured at baseline, after 8 weeks, and after 4 weeks washout. Polymorphisms in the gene for the antioxidant enzyme paraoxonase-1 gene (position 192) were measured. The diabetics had increased DNA oxidative susceptibility (P=0.008), without increased LDL oxidative susceptibility. There was a direct relationship between DNA oxidative susceptibility and baseline plasma alpha-tocopherol in the diabetes group alone (r=0.421, r(2)=0.177 and P=0.023), but DNA and LDL oxidative susceptibility were not influenced by alpha-tocopherol supplementation in either group in this regimen. Paraoxonase-1 gene polymorphisms did not contribute to LDL or DNA oxidative susceptibility or response to alpha-tocopherol. Increased DNA oxidative susceptibility, therefore, can occur in Type II diabetes without increased LDL oxidative susceptibility, but alpha-tocopherol supplementation in this regimen has no influence on DNA or LDL oxidative susceptibility in Type II diabetes or controls. Polymorphisms in the paraoxonase gene (position 192) are not associated with differences in oxidative susceptibility or responses to alpha-tocopherol.
Assuntos
Antioxidantes/uso terapêutico , Dano ao DNA/efeitos dos fármacos , Diabetes Mellitus Tipo 2/genética , Lipoproteínas LDL/sangue , Vitamina E/uso terapêutico , Adulto , Idoso , Antioxidantes/metabolismo , Arildialquilfosfatase , Diabetes Mellitus Tipo 2/sangue , Método Duplo-Cego , Esterases/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oxirredução/efeitos dos fármacos , Polimorfismo Genético , Estudos Prospectivos , Vitamina E/sangueRESUMO
OBJECTIVE: To assess the effects of supplementation with the carotenoids, beta-carotene or lycopene, at levels achievable within a diet rich in fruit and vegetables, on immune function in a group of free-living healthy elderly. DESIGN: A double-blind randomized placebo-controlled trial. T cell subsets and the expression of functionally associated cell surface molecules, quantified by flow cytometry, and lectin-stimulated lymphocyte proliferation, were compared before and following the treatment period. SUBJECTS: Fifty-eight subjects aged over 65 y were recruited; 52 were included in the final analysis. INTERVENTIONS: Participants received one placebo, one lycopene (13.3 mg) or one beta-carotene (8.2 mg) capsule daily for 12 weeks. RESULTS: No significant differences were observed in any of the parameters examined following either lycopene or beta-carotene supplementation. CONCLUSIONS: In well-nourished, free-living, healthy elderly individuals, supplementation with relatively low levels of beta-carotene or lycopene is not associated with either a beneficial or detrimental effects on several aspects of cell-mediated immunity.
Assuntos
Carotenoides/administração & dosagem , Suplementos Nutricionais , Imunidade Celular/efeitos dos fármacos , beta Caroteno/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Carotenoides/sangue , Carotenoides/imunologia , Cromatografia Líquida de Alta Pressão , Citocinas/biossíntese , Método Duplo-Cego , Ácidos Graxos/sangue , Feminino , Citometria de Fluxo , Frutas/química , Humanos , Licopeno , Ativação Linfocitária/efeitos dos fármacos , Contagem de Linfócitos , Subpopulações de Linfócitos/efeitos dos fármacos , Masculino , Verduras/química , beta Caroteno/sangue , beta Caroteno/imunologiaRESUMO
AIMS: To examine the effect of n-3 polyunsaturated fatty acid supplements on the monocyte surface expression of adhesion molecules involved in proatherogenic monocyte-endothelial interactions, and on pro-inflammatory mediators in Type 2 diabetes mellitus. METHODS: Twenty-nine subjects with Type 2 diabetes and 21 controls without diabetes were studied. Monocyte expression of leucocyte function-associated antigens 1 and 3, intercellular adhesion molecule-1, and the major histocompatibility complex class II molecule HLA-DR were measured using a laser flow cytometric method. Supplementation with 2.08 g n-3 fatty acids for 21 days was undertaken and measurements repeated. Plasma soluble adhesion molecule concentrations, plasminogen activator inhibitor-1 activity and antigen and pro-inflammatory mediators (cysteinyl leukotriene and monocyte leukotriene B4) were also measured. RESULTS: Groups did not differ in monocyte expression of adhesion molecules or HLA-DR, or in leukotriene production although plasma soluble adhesion molecule concentrations were higher in the diabetes groups (P<0.05). n-3 fatty acid supplementation influenced neither the expression of these molecules nor plasma soluble adhesion molecule concentrations or leukotriene production. CONCLUSIONS: This study does not support increased monocyte adhesion molecule expression or abnormal monocyte production of pro-inflammatory mediators as mechanisms for increased atherogenic risk in Type 2 diabetes. Cardioprotective actions of n-3 fatty acids may not be mediated through these mechanisms.
Assuntos
Antígenos CD58/sangue , Diabetes Mellitus Tipo 2/imunologia , Diabetes Mellitus Tipo 2/terapia , Suplementos Nutricionais , Ácidos Graxos Ômega-3/uso terapêutico , Molécula 1 de Adesão Intercelular/sangue , Antígeno-1 Associado à Função Linfocitária/sangue , Monócitos/imunologia , Plaquetas/química , Plaquetas/metabolismo , Diabetes Mellitus Tipo 2/sangue , Inglaterra , Ácidos Graxos não Esterificados/sangue , Ácidos Graxos Ômega-3/farmacologia , Antígenos HLA-DR/sangue , Humanos , Inflamação , Leucotrieno B4/sangue , Masculino , Pessoa de Meia-Idade , Monócitos/efeitos dos fármacos , Inibidor 1 de Ativador de Plasminogênio/sangue , Valores de Referência , População BrancaRESUMO
It has been suggested that dietary carotenoids can enhance immune function. Supplementation with beta-carotene (15 mg daily) was previously shown to enhance human monocyte function. To examine the effect of other dietary carotenoids, two similar independent studies were done. Healthy adult male nonsmokers were randomly assigned to receive lycopene (study 1), lutein (study 2), or placebo for 26 days, followed by the alternative treatment for another 26 days. The expression of functionally related monocyte surface molecules was quantified by laser flow cytometry before and after each treatment period. There was a significant increase in plasma levels of each carotenoid following dietary supplementation, but the effects on monocyte surface molecule expression were not as striking as those observed after beta-carotene supplementation. These findings emphasize that it cannot be assumed that the effect of one carotenoid will be the same as another, even at the same level of intake.
Assuntos
Antígenos CD/sangue , Antioxidantes/farmacologia , Carotenoides/farmacologia , Antígenos HLA-D/sangue , Luteína/farmacologia , Monócitos/imunologia , Adolescente , Adulto , Carotenoides/administração & dosagem , Carotenoides/sangue , Estudos Cross-Over , Suplementos Nutricionais , Humanos , Luteína/administração & dosagem , Licopeno , Masculino , Pessoa de Meia-Idade , Monócitos/efeitos dos fármacos , Placebos , beta Caroteno/farmacologiaRESUMO
Diets rich in n-3 polyunsaturated fatty acids (PUFAs) are associated with suppression of cell-mediated immune responses, but the mechanisms are unclear. We hypothesized that n-3 PUFAs can inhibit the function of human antigen-presenting cells. A prerequisite for this role of blood monocytes is the cell surface expression of major histocompatibility complex (MHC) class II molecules [human leukocyte antigen (HLA)-DR, -DP, and -DQ], aided by the presence of intercellular adhesion molecule-1 (ICAM-1) and leukocyte function associated antigens 1 and 3. We showed previously that the n-3 PUFA eicosapentaenoic acid (EPA) inhibits the expression of HLA-DR on unstimulated human monocytes in vitro, but that docosahexaenoic acid (DHA) enhances its expression. However, both n-3 PUFAs suppress the expression of HLA-DR, HLA-DP, and ICAM-1 on interferon-gamma-activated monocytes. We also established that dietary fish-oil supplementation can inhibit the expression of these surface molecules on circulating human monocytes. We subsequently showed that when EPA and DHA were combined in the same ratio as is commonly found in fish-oil-supplement capsules (3:2), there was no significant effect in vitro on the expression of HLA-DR on unstimulated monocytes, but the expression on activated monocytes remained significantly inhibited. In the same in vitro system, the ability of activated monocytes to present antigen to autologous lymphocytes was significantly reduced after culture with the combined n-3 PUFAs. These findings provide one potential mechanism for the beneficial effect of fish oil in the treatment of rheumatoid arthritis, a disorder associated with elevated expression of MHC class II and adhesion molecules on monocytes present within affected joints.
Assuntos
Células Apresentadoras de Antígenos/imunologia , Gorduras Insaturadas na Dieta/imunologia , Ácidos Graxos Ômega-3/imunologia , Monócitos/imunologia , Adulto , Anticorpos Monoclonais , Artrite Reumatoide/dietoterapia , Artrite Reumatoide/imunologia , Ácidos Docosa-Hexaenoicos/imunologia , Ácido Eicosapentaenoico/imunologia , Feminino , Citometria de Fluxo , Genes MHC da Classe II/imunologia , Humanos , Ativação Linfocitária/imunologia , Masculino , Pessoa de Meia-IdadeRESUMO
Polyunsaturated fatty acids (PUFAs) are highly susceptible to free radical attack. In vitro studies of carotenoids--including beta-carotene, lycopene, and lutein--have shown them to be effective quenchers of singlet oxygen, to have good radical-trapping properties, or to be effective peroxyl radical scavengers (or to have a combination of these qualities). If carotenoids act as antioxidants in vivo, then arguably, plasma PUFA should be conserved. The objective of the current study was to answer the question "Does supplementation with beta-carotene, lycopene, or lutein, at dietarily achievable levels, over a time period known to significantly increase circulating carote concentrations, lead to an observable increase in fasting plasma PUFA?" The normal diets of human volunteers were supplemented with either 15 mg/day beta-carotene (n = 25), lycopene (n = 23), or lutein (n = 21) for 26 days in three independent double-blind, placebo-controlled supplementation studies. Supplementation with beta-carotene increased plasma linoleic acid but left the polyunsaturated:saturated (P:S) fatty acid ratio unaltered. In contrast, supplementation with lycopene reduced linoleic acid, which resulted in a large decrease in the P:S ratio. Lutein supplementation had no effect. It was concluded that neither beta-carotene, lycopene, nor lutein supplementation engender antioxidant effects that lead to the widespread general conservation of plasma PUFAs. Beta-carotene and lycopene supplementation appear to interact with the metabolism of linoleic acid, the "essential" fatty acid, resulting in either an increase (beta-carotene) or decrease (lycopene) in its plasma concentration. Alterations in plasma 18:2 or P:S ratios could ultimately lead to changes in tissue cellular membrane composition and hence to alterations in membrane fluidity and cell-surface protein expression.
Assuntos
Antioxidantes/administração & dosagem , Carotenoides/administração & dosagem , Suplementos Nutricionais , Ácidos Graxos Insaturados/sangue , Luteína/administração & dosagem , beta Caroteno/administração & dosagem , Adolescente , Adulto , Carotenoides/sangue , Método Duplo-Cego , Humanos , Luteína/sangue , Licopeno , Masculino , Pessoa de Meia-Idade , beta Caroteno/sangueRESUMO
Many epidemiological studies have shown an association between diets rich in carotenoids and a reduced incidence of many forms of cancer, and it has been suggested that the antioxidant properties of these compounds are a causative factor. Attention has focused on the potential role of one specific carotenoid, beta-carotene, in preventing cancer, and numerous publications have described in vitro experiments and animal studies which suggest that not only can this carotenoid protect against the development of cancer, but also several other chronic diseases. Since the immune system plays a major role in cancer prevention, it has been suggested that beta-carotene may enhance immune cell function. Several human trials, using dietary beta-carotene supplementation with a wide range of intakes, have been undertaken to address this hypothesis. The general conclusion of these studies is that this compound can enhance cell-mediated immune responses, particularly in the elderly. The present article will review some of these human studies and, hopefully, complement the reviews of other authors associated with the present symposium, some of whom will also describe work in this area. Potential mechanisms for the effects of carotenoids on immune function will also be reviewed. Finally, possible reasons for the failure of three major prospective studies to demonstrate a beneficial effect of beta-carotene supplementation on lung cancer risk will be discussed.
Assuntos
Antioxidantes/farmacologia , Carotenoides/farmacologia , Imunidade/efeitos dos fármacos , Carotenoides/administração & dosagem , Humanos , Linfócitos/imunologia , Monócitos/imunologia , Neoplasias/prevenção & controle , Estresse Oxidativo , beta Caroteno/administração & dosagem , beta Caroteno/farmacologiaRESUMO
The immune system is highly reliant on accurate cell-cell communication for optimal function, and any damage to the signalling systems involved will result in an impaired immune responsiveness. Oxidant-mediated tissue injury is a particular hazard to the immune system, since phagocytic cells produce reactive oxygen species as part of the body's defence against infection. Adequate amounts of neutralizing antioxidants are required, therefore, to prevent damage to the immune cells themselves. Many antioxidants can be obtained directly from the diet (e.g. ascorbic acid, alpha-tocopherol, carotenoids and polyphenolic flavonoids) or require micronutrients as integral components (e.g. Se in the metalloenzyme glutathione peroxidase (EC 1.11.1.9)). Numerous epidemiological studies have found strong associations between diets rich in antioxidant nutrients and a reduced incidence of cancer, and it has been suggested that a boost to the body's immune system by antioxidants might, at least in part, account for this. Although more striking effects have been observed in the elderly, there is also evidence that antioxidant nutrients can modify cell-mediated immune responses in younger individuals. Indeed, it might be essential to have an adequate intake of antioxidant nutrients from an early age in order to help prevent the development of, or at least delay the onset of, several degenerative disorders. The present paper will review the effects of specific nutrients on immune function in young to middle-aged human subjects, focusing on the antioxidant vitamins C and E, and on Se. A further review, dealing more specifically with the effects of carotenoids on human immune function, will be presented at a forthcoming meeting of the Nutrition Society.
Assuntos
Antioxidantes/administração & dosagem , Dieta , Imunidade , Adulto , Ácido Ascórbico , Radicais Livres , Humanos , Pessoa de Meia-Idade , Estresse Oxidativo , Espécies Reativas de Oxigênio , Selênio , Vitamina EAssuntos
Gorduras Insaturadas na Dieta/farmacologia , Ácidos Graxos Ômega-3/farmacologia , Monócitos/imunologia , Apresentação de Antígeno , Quimiotaxia , Citocinas/biossíntese , Citotoxicidade Imunológica , Ácidos Graxos Ômega-3/administração & dosagem , Humanos , Inflamação/imunologia , FagocitoseRESUMO
N-3 polyunsaturated fatty acid (PUFA)-rich diets are associated with suppression of cell-mediated immune responses, but the mechanisms are unclear. Specific immune responses are initiated by antigen-presenting cells (APC). We have previously shown in vitro that the n-3 PUFA, eicosapentaenoic acid (EPA), inhibits the expression of HLA-DR, an MHC class II molecule required for normal APC function on human blood monocytes. In contrast, docosahexaenoic acid (DHA) enhanced the expression of this molecule on unstimulated monocytes, but both n-3 PUFA suppressed its expression on interferon-gamma (IFN-gamma)-activated monocytes. In the present study we show that when EPA and DHA were combined at the same ratio as is commonly found in fish oil supplement capsules (3:2) there was no significant effect in vitro on the expression of HLA-DR on unstimulated monocytes, but the expression on IFN-gamma-activated monocytes remained significantly inhibited. In the same in vitro system a significant reduction in the ability of IFN-gamma-activated monocytes to present tetanus toxoid antigen to autologous lymphocytes was observed following culture with the combined n-3 PUFA. These findings support previous animal studies which suggest that n-3 PUFA can inhibit the antigen-presenting function of mononuclear phagocytes.