Pode a glutamina modular a imunidade? / Can the glutamine modulate the immunity?

Dentre os diversos nutrientes pesquisados, denominados "imunomoduladores" ou "imunonutrientes", tem-se ressaltado o papel da glutamina, que é um aminoácido não essencial, sintetizado pelo organismo em quantidades suficientes nos estados fisiológicos. Possui relevante participação em numerosas vias metabólicas, sobretudo, as relacionadas com a homeostase orgânica. Entretanto, estados hipercatabólicos, como o estresse, encontram-se associados ao aumento da demanda orgânica de glutamina. Nesta revisão, serão discutidos o papel metabólico da glutamina e as implicações de sua disponibilidade no funcionamento das células imunes

Inmunoregulacion mediada por Calcitriol / Inmunoregulatory role of Calcitiol

El papel clásico endocrino del calcitrol (la,25-dihidroxivitamina D3) en la homeostasis del calcio es bien conocido. Los hallazgos relativamente recientes de la presencia del receptor de calcitrol en monocitos, linfocitos y diversas líneas celulares, y el hallazgo de la producción ectópica y localizada del calcitrol por los macrófagos, sugiere un papel importante de esta vitamina/hormona en eventos de inmunoregulación. A partir de la nueva evidencia experimental, es claro, a diferencia de los planteamientos iniciales que consideraban al calcitrol como un agente inmunosupresor, que esta hormona es capaz de estimular y de suprimir la función inmune, dependiendo de las condiciones de activación y del microambiente inmunológico. La información clínica disponible y la experimentación in vivo e in vitro apoyan un efecto inmunomodulador del calcitrol; éste debe ser considerado, por lo tanto, como uno mas de la larga y creciente lista de moduladores

Gut mucosal immunostimulation by lactic acid bacteria

The beneficial properties of lactic acid bacteria (LAB) on human health have been frequently demonstrated. The interaction of LAB with the lymphoid cells associated to the gut to activate the mucosal immune system and the mechanisms by which they can exert an adjuvant effect is still unclear, as well as if this property is common for all the LAB. We studied the influence of the oral administration of different geneous of LAB such as Lactobacillus casei, L. acidophilus, L. rhamnosus, L. delbrueckii subsp. bulgaricus, L. plantarum, Lactococcus lactis and Streptococcus thermophilus. We determined if the LAB assayed were able to stimulate the specific, the non-specific immune response (inflammatory response), or both. We demonstrated that all the bacteria assayed were able to increase the number of IgA producing cells associated to the lamina propria of small intestine. This effect was dose dependent. The increase in IgA+ producing cells was not always correlated with an increase in the CD4+ T cell number, indicating that some LAB assayed only induced clonal expansion of B cells triggered to produce IgA. Most of them, induced an increase in the number of cells involved in the inflammatory immune response. CD8+ T cell were diminished or not affected, with exception of L. plantarum that induced an increase at low dose. This fact would mean that LAB are unable to induce cytotoxicity mechanisms. We demonstrated the importance in the selection of LAB to be used as gut mucosal adjuvant. The different behaviours observed among them on the gut mucosal immune response, specially those that induce inflammatory immune response, show that not all the LAB can be used as oral adjuvant and that the beneficial effect of them can not generalized to genous or specie. The immunoadjuvant capacity would be a property of the strain assayed.

Acidos grasos omega-3 de cadena larga en la nutrición humana y animal: un modelo de alimentos funcionales / Long chain omega-3 fatty acids in human and animal nutrition: a model for functional foods

Los ácidos grasos omega-3 de cadena larga, especialmente el ácido eicosapentaenoico (EPA) y el ácido docosahexaenoico (DHA) han adquirido gran importancia por sus efectos en la salud y en la nutrición tanto humana como animal. Estos ácidos grasos están disponibles principalmente a partir de los productos de origen marino, siendo los peces y los productos industriales que se obtienen de estos, la harina y el aceite, las fuentes más importantes. La necesidad de suplementar nuestra nutrición con EPA y/o DHA, debido al déficit creciente que se observa en su consumo en la dieta occidental, ha motivado a la industria de alimentación humana y animal, a buscar procedimientos que permitan aumentar la ingesta de EPA y DHA a través del desarrollo de alimentos funcionales. Actualmente se elabora una gran variedad de productos que contienen EPA y DHA, o solamente DHA, de acuerdo a los requerimientos. Es así que es posible adquirir leches, yogurts, bebidas, margarinas, mayonesas, pan, productos para la alimentación materno-infantil, entre otros, enriquecidos con diferentes cantidades de estos ácidos grasos. Otra alternativa muy interesante y de gran proyección es el enriquecimiento de la carne y los huevos de aves, de la carne de cerdos y de la leche de vaca, con ácidos grasos omega-3 de cadena larga a través de la manipulación nutricional de estos animales. Este trabajo resume los principales productos enriquecidos con EPA y DHA disponibles en el mercado, y discute el rol que puede tener la industria alimentaria en la proyección hacia la salud y la nutrición humana al enriquecer alimentos con ácidos grasos omega-3 de cadena larga

Dehydroepiandrosterone-dependent induction of peroxisomal proliferation can be reduced by aspartyl esterification without attenuation of inhibitory bone loss in ovariectomy animal model

The purpose of this study was to determine whether esterification of dehydroepiandrosterone with aspartate (DHEA-aspartate) could reduce peroxisomal proliferation induced by DHEA itself, without loss of antiosteoporotic activity. Female Sprague-Dawley rats were ovariectomized, then DHEA or DHEA-aspartate was administered intraperitoneally at 0.34 mmol/kg BW 3 times a week for 8 weeks. DHEA-aspartate treatment in ovariectomized rats significantly increased trabeculae area in tibia as much as DHEA treatment. Urinary Ca excretion was not significantly increased by DHEA or DHEA-aspartate treatment in ovariectomized rats, while it was significantly increased by ovariectomy. Osteocalcin concentration and alkaline phosphatase activity in serum and cross linked N-telopeptide type I collagen level in urine were not significantly different between DHEA-aspartate and DHEA treated groups. DHEA-aspartate treatment significantly reduced liver weight and hepatic palmitoyl-coA oxidase activity compared to DHEA treatment. DHEA-aspartate treatment maintained a nearly normal morphology of peroxisomes, while DHEA treatment increased the number and size of peroxisomes in the liver. According to these results, it is concluded that DHEA-aspartate ester has an inhibitory effect on bone loss in ovariectomized rats with a marked reduction of hepatomegaly and peroxisomal proliferation compared to DHEA.