Dietary animal plasma proteins improve the intestinal immune response in senescent mice

Increased life expectancy has promoted research on healthy aging. Aging is accompanied by increased non-specific immune activation (inflammaging) which favors the appearance of several disorders. Here, we study whether dietary supplementation with spray-dried animal plasma (SDP), which has been shown to reduce the activation of gut-associated lymphoid tissue (GALT) in rodents challenged by S. aureus enterotoxin B (SEB), and can also prevent the effects of aging on immune system homeostasis. We first characterized GALT in a mouse model of accelerated senescence (SAMP8) at different ages (compared to mice resistant to accelerated senescence; SAMR1). Second, we analyzed the SDP effects on GALT response to an SEB challenge in SAMP8 mice. In GALT characterization, aging increased the cell number and the percentage of activated Th lymphocytes in mesenteric lymph nodes and Peyer's patches (all, p < 0.05), as well as the expression of IL-6 and TNF-α in intestinal mucosa (both, p < 0.05). With respect to GALT response to the SEB challenge, young mice showed increased expression of intestinal IL-6 and TNF-α, as well as lymphocyte recruitment and activation (all, p < 0.05). However, the immune response of senescent mice to the SEB challenge was weak, since SEB did not change cell recruitment or the percentage of activated Th lymphocytes. Mice supplemented with SDP showed improved capacity to respond to the SEB challenge, similar to the response of the young mice. These results indicate that senescent mice have an impaired mucosal immune response characterized by unspecific GALT activation and a weak specific immune response. SDP supplementation reduces non-specific basal immune activation, allowing for the generation of specific responses

Development and characterization of an effective food allergy model in Brown Norway rats

Background: Food allergy (FA) is an adverse health effect produced by the exposure to a given food. Currently, there is no optimal animal model of FA for the screening of immunotherapies or for testing the allergenicity of new foods. Objective: The aim of the present study was to develop an effective and rapid model of FA in Brown Norway rats. In order to establish biomarkers of FA in rat, we compared the immune response and the anaphylactic shock obtained in this model with those achieved with only intraperitoneal immunization. Methods: Rats received an intraperitoneal injection of ovalbumin (OVA) with alum and toxin from Bordetella pertussis, and 14 days later, OVA by oral route daily for three weeks (FA group). A group of rats receiving only the i.p. injection (IP group) were also tested. Serum anti-OVA IgE, IgG1, IgG2a, IgG2b and IgA antibodies were quantified throughout the study. After an oral challenge, body temperature, intestinal permeability, motor activity, and mast cell protease II (RMCP-II) levels were determined. At the end of the study, anti-OVA intestinal IgA, spleen cytokine production, lymphocyte composition of Peyer's patches and mesenteric lymph nodes, and gene expression in the small intestine were quantified. Results: Serum OVA-specific IgG1, IgG2a and IgG2b concentrations rose with the i.p. immunization but were highly augmented after the oral OVA administration. Anti-OVA IgE increased twofold during the first week of oral OVA gavage. The anaphylaxis in both IP and FA groups decreased body temperature and motor activity, whereas intestinal permeability increased.Interestingly, the FA group showed a much higher RMCP II serum protein and intestinal mRNA expression. Conclusions: These results show both an effective and relatively rapid model of FA assessed by means of specific antibody titres and the high production of RMCP-II and its intestinal gene expression

Efectes de la suplementació dietètica amb proteïnes plasmàtiques sobre la resposta immunitària i el deteriorament cognitiu en un model d’envelliment

[cat] En els últims anys s’ha produït un increment de l’esperança de vida que ha despertat un gran interès en promoure un envelliment saludable. Habitualment, la senescència va acompanyada de diferents trastorns i malalties en la base de les quals hi ha una desregulació del sistema immunitari. Aquesta desregulació implica un increment de l’activació basal del sistema immunitari que comporta un augment de l’estat inflamatori de baixa intensitat, conegut com a inflammaging. Alguns suplements dietètics redueixen l’activació del sistema immunitari, prevenint el deteriorament cognitiu associat a l’envelliment a través d’una connexió entre l’intestí i el cervell. En animals acabats de deslletar, la suplementació dietètica amb proteïnes plasmàtiques (SDP) millora la funció de barrera de la mucosa intestinal i modula el grau d’activació del teixit limfoide associat a l’intestí durant un procés inflamatori. En aquest estudi hem demostrat que, als 6 mesos d’edat, els ratolins amb envelliment accelerat (SAMP8) presenten una activació inespecífica del sistema immunitari intestinal així com una menor capacitat de resposta front a l’enterotoxina B d’S. aureus. La suplementació dietètica amb SDP durant 4 mesos disminueix l’activació inespecífica del sistema immunitari intestinal dels ratolins senescents, ja que hi ha una menor expressió de citocines proinflamatòries; a més, la resposta immunitària intestinal d’aquests animals front a l’enterotoxina B d’S. aureus és similar a la dels ratolins joves. Els ratolins SAMP8 de 6 mesos presenten un deteriorament de la memòria a curt i a llarg termini que s’associa a un increment en l’expressió de citocines proinflàmatòries, a la presència d’agents oxidants a l’encèfal i a una major permeabilitat de la barrera hematoencefàlica. Els ratolins senescents presenten una major fosforilació de la proteïna Tau que els ratolins joves, fet que està relacionat amb trastorns cognitius com els que s’observen en la malaltia d’Alzheimer. La suplementació dietètica amb proteïnes plasmàtiques atenua la majoria d’aquests efectes de l’envelliment sobre la funcionalitat cerebral, gràcies a la connexió que existeix entre el sistema immunitari intestinal i altres mucoses i òrgans sistèmics.[eng] The increase in life expectancy that has occurred in recent years has generated a great interest in promoting a healthy aging. Usually, senescence is accompanied by different disorders and diseases, at the base of which there is a deregulation of the immune system. This deregulation implies an increase in the basal activation of the immune system which involves an increment of the low intensity inflammatory state known as inflammaging. Some dietary supplements may reduce the activation of the immune system, preventing the cognitive deterioration associated with aging through the connection between the intestine and the brain. In weaned animals, plasma protein dietary supplementation (SDP) improves the barrier function of the intestinal mucosa and modulates the degree of activation of the intestinal lymphoid tissue during an intestinal inflammation. In this study we have demonstrated that, at 6-month-old, mice with accelerated aging (SAMP8) present a non-specific activation of the intestinal immune system as well as a lower response capacity to S. aureus enterotoxin. Dietary supplementation with SDP for 4 months decreases nonspecific activation of the intestinal immune system of senescent mice, as there is a lower expression of proinflammatory cytokines. In addition, the intestinal immune response of these animals to S. aureus enterotoxin is similar to that of young mice. The 6-month-old SAMP8 mice present short- term and long-term memory impairment associated with increased proinflammatory cytokines, the presence of oxidizing agents in the brain and increased permeability of the blood-brain barrier. Senescent mice show higher phosphorylation of Tau protein than young mice, which is related to cognitive disorders such as those observed in Alzheimer's disease. Dietary supplementation with plasma proteins attenuates most of these effects of aging on brain functionality, through the connection between the intestinal immune system and other mucosal and systemic organs

Dietary Animal Plasma Proteins Improve the Intestinal Immune Response in Senescent Mice

Increased life expectancy has promoted research on healthy aging. Aging is accompanied by increased non-specific immune activation (inflammaging) which favors the appearance of several disorders. Here, we study whether dietary supplementation with spray-dried animal plasma (SDP), which has been shown to reduce the activation of gut-associated lymphoid tissue (GALT) in rodents challenged by S. aureus enterotoxin B (SEB), and can also prevent the effects of aging on immune system homeostasis. We first characterized GALT in a mouse model of accelerated senescence (SAMP8) at different ages (compared to mice resistant to accelerated senescence; SAMR1). Second, we analyzed the SDP effects on GALT response to an SEB challenge in SAMP8 mice. In GALT characterization, aging increased the cell number and the percentage of activated Th lymphocytes in mesenteric lymph nodes and Peyer’s patches (all, p &lt; 0.05), as well as the expression of IL-6 and TNF-α in intestinal mucosa (both, p &lt; 0.05). With respect to GALT response to the SEB challenge, young mice showed increased expression of intestinal IL-6 and TNF-α, as well as lymphocyte recruitment and activation (all, p &lt; 0.05). However, the immune response of senescent mice to the SEB challenge was weak, since SEB did not change cell recruitment or the percentage of activated Th lymphocytes. Mice supplemented with SDP showed improved capacity to respond to the SEB challenge, similar to the response of the young mice. These results indicate that senescent mice have an impaired mucosal immune response characterized by unspecific GALT activation and a weak specific immune response. SDP supplementation reduces non-specific basal immune activation, allowing for the generation of specific responses

Cytokine production by spleen cells after stimulation with OVA.

<p>Results are expressed as mean ± S.E.M.</p><p>*<i>p</i> < 0.05 <i>vs</i>. RF group,</p><p>^ϕ<i>p</i> < 0.05 <i>vs</i>. IP group.</p><p>Cytokine production by spleen cells after stimulation with OVA.</p

Lymphocyte composition isolated from A) Peyer’s patches, B) mesenteric lymph nodes, and C) mesenteric lymph nodes after culturing for 96 h in the presence or absence of OVA.

<p>In A and B, white bars represent RF group, black bars represent IP group and grey-striped bars represent FA group. In C, white bars summarize values without stimulus and striped bars represent values after OVA stimulation. Results are expressed as mean ± S.E.M. (n = 8). *<i>p</i> < 0.05 <i>vs</i>. non stimulated condition.</p

Variables measured during 2 h after anaphylactic shock induction: A) body temperature, B) serum RMCP-II concentration and C) serum βLG concentration.

<p>White bars represent RF group, black bars represent IP group and grey-striped bars represent FA group. Results are expressed as mean ± S.E.M. (n = 8). *<i>p</i> < 0.05 <i>vs</i>. RF group and ^ϕ<i>p</i> < 0.05 <i>vs</i>. IP group.</p

Motor activity for 21-min period.

<p><b>A)</b> Basal motor activity assessed 24 h before the AR induction; <b>B)</b> area under the curve from the whole studied period before AR induction; <b>C)</b> motor activity assessed immediately after AR induction; <b>D)</b> area under the curve from the whole studied period after AR induction; <b>E)</b> percentage of motor activity decrease after AR induction referring to pre-darkness, darkness, post-darkness and the whole period. ○ or white bars represent RF group, ▼ or black bars represent IP group and </p><p></p><p></p><p><mn>∎</mn></p><p></p><p></p> or grey-striped bars represent FA group. In A and C, shadow period corresponds to darkness. Results are expressed as mean ± S.E.M. (n = 8). *<i>p</i> < 0.05 <i>vs</i>. RF group.<p></p

Concentrations of OVA-specific antibodies during post-immunization period.

<p><b>A)</b> serum IgG1, <b>B)</b> serum IgG2a, <b>C)</b> serum IgG2b, <b>D)</b> serum IgE, <b>E)</b> serum IgA and <b>F)</b> intestinal IgA. White bars represent RF group, ▼ or black bars represent IP group and </p><p></p><p></p><p><mn>∎</mn></p><p></p><p></p> or grey-striped bars represent FA group. Shadow period corresponds to oral administration of OVA in FA group. Results are expressed as mean ± S.E.M. (n = 8). *<i>p</i> < 0.05 <i>vs</i>. RF group and ^ϕ<i>p</i> < 0.05 <i>vs</i>. IP group.<p></p

Relative gene expression in small intestine.

<p>Expression levels were normalized using HPRT as the endogenous housekeeping gene and were expressed as percentage in comparison with the RF group, which was considered as 100% gene expression. White bars represent RF group, black bars represent IP group and grey-striped bars represent FA group. Results are expressed as mean ± S.E.M. (n = 8). *<i>p</i> < 0.05 <i>vs</i>. RF group.</p