Moderate Aerobic Exercise Induces Homeostatic IgA Generation in Senile Mice.

A T-cell-independent (TI) pathway activated by microbiota results in the generation of low-affinity homeostatic IgA with a critical role in intestinal homeostasis. Moderate aerobic exercise (MAE) provides a beneficial impact on intestinal immunity, but the action of MAE on TI-IgA generation under senescence conditions is unknown. This study aimed to determine the effects of long-term MAE on TI-IgA production in young (3 month old) BALB/c mice exercised until adulthood (6 months) or aging (24 months). Lamina propria (LP) from the small intestine was obtained to determine B cell and plasma cell sub-populations by flow cytometry and molecular factors related to class switch recombination [Thymic Stromal Lymphopoietin (TSLP), A Proliferation-Inducing Ligand (APRIL), B Cell Activating Factor (BAFF), inducible nitric oxide synthase (iNOS), and retinal dehydrogenase (RDH)] and the synthesis of IgA [α-chain, interleukin (IL)-6, IL-21, and Growth Factor-ß (TGF-ß)]; and epithelial cells evaluated IgA transitosis [polymeric immunoglobulin receptor (pIgR), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), IL-4] by the RT-qPCR technique. The results were compared with data obtained from sedentary age-matched mice. Statistical analysis was computed with ANOVA, and p < 0.05 was considered to be a statistically significant difference. Under senescence conditions, MAE promoted the B cell and IgA+ B cells and APRIL, which may improve the intestinal response and ameliorate the inflammatory environment associated presumably with the downmodulation of pro-inflammatory mediators involved in the upmodulation of pIgR expression. Data suggested that MAE improved IgA and downmodulate the cytokine pro-inflammatory expression favoring homeostatic conditions in aging.

Exercise improves intestinal IgA production by T-dependent cell pathway in adults but not in aged mice.

Introduction: Hypermutated high-affinity immunoglobulin A (IgA), neutralizes toxins and drives the diversification of bacteria communities to maintain intestinal homeostasis although the mechanism underlies the impact of moderate aerobic exercise (MAE) on the IgA-generation via T-dependent (TD) is not fully know. Therefore, the aim of this study was to determine the effect of long-time MAE on the production of IgA through the TD pathway in Peyer´s patches of the small intestine from aged mice. Methods: MAE protocol consisted of twenty 3-month-old (young) BALB/c mice running in an endless band at 0° inclination and a speed of 10 m/h for 5 days a week and resting 2 days on the weekend until reaching 6-month-old (adulthood, n=10) or 24-month-old (aging, n=10). Groups of young, adult, or elderly mice were included as sedentary controls (n=10/per group). At 6 or 24 months old, all were sacrificed, and small intestine samples were dissected to prepare intestinal lavages for IgA quantitation by ELISA and to obtain suspensions from Peyer´s patches (PP) and lamina propria (LP) cells for analysis of T, B, and plasma cell subpopulations by flow cytometry and mRNA analysis expression by RT-qPCR of molecular factors related to differentiation of B cells to IgA+ plasma cells, class switch recombination, and IgA-synthesis. Statistical analysis was computed with two-way ANOVA (factor A=age, factor B=group) and p<0.05 was considered for statistically significant differences. Results: Compared to age-matched sedentary control, in exercised elderly mice, parameters were either increased (IgA concentration, IL-21, IL-10 and RDH mRNA expression), decreased (α-chain mRNA, B cells, mIgA+ B cells, mIgM+ B cells and IL-4 mRNA) or unchanged (PP mIgA+ plasmablasts and LP cyt-IgA+ plasma cells). Regarding the exercised adult mice, they showed an up-modulation of IgA-concentration, mRNA expression IL-21, IL-10, and RDH and cells (PP B and T cells, mIgM+ plasmablasts and LP cyt-IgA+plasma cells). Conclusion: Our findings suggest that MAE restored the IgA production in adult mice via the TD cell pathway but does not in aged mice. Other studies are necessary to know in more detail the impact of long-time MAE on the TD pathway to produce IgA in aging.

Role of Stress on Driving the Intestinal Paracellular Permeability.

The gut epithelium is a polarized monolayer that exhibits apical and basolateral membrane surfaces. Monolayer cell components are joined side by side via protein complexes known as tight junction proteins (TJPs), expressed at the most apical extreme of the basolateral membrane. The gut epithelium is a physical barrier that determinates intestinal permeability, referred to as the measurement of the transit of molecules from the intestinal lumen to the bloodstream or, conversely, from the blood to the gut lumen. TJPs play a role in the control of intestinal permeability that can be disrupted by stress through signal pathways triggered by the ligation of receptors with stress hormones like glucocorticoids. Preclinical studies conducted under in vitro and/or in vivo conditions have addressed underlying mechanisms that account for the impact of stress on gut permeability. These mechanisms may provide insights for novel therapeutic interventions in diseases in which stress is a risk factor, like irritable bowel syndrome. The focus of this study was to review, in an integrative context, the neuroendocrine effects of stress, with special emphasis on TJPs along with intestinal permeability.

Lactoferrin as a Component of Pharmaceutical Preparations: An Experimental Focus.

Lactoferrin is an 80 kDa monomeric glycoprotein that exhibits multitask activities. Lactoferrin properties are of interest in the pharmaceutical field for the design of products with therapeutic potential, including nanoparticles and liposomes, among many others. In antimicrobial preparations, lactoferrin has been included either as a main bioactive component or as an enhancer of the activity and potency of first-line antibiotics. In some proposals based on nanoparticles, lactoferrin has been included in delivery systems to transport and protect drugs from enzymatic degradation in the intestine, favoring the bioavailability for the treatment of inflammatory bowel disease and colon cancer. Moreover, nanoparticles loaded with lactoferrin have been formulated as delivery systems to transport drugs for neurodegenerative diseases, which cannot cross the blood-brain barrier to enter the central nervous system. This manuscript is focused on pharmaceutical products either containing lactoferrin as the bioactive component or formulated with lactoferrin as the carrier considering its interaction with receptors expressed in tissues as targets of drugs delivered via parenteral or mucosal administration. We hope that this manuscript provides insights about the therapeutic possibilities of pharmaceutical Lf preparations with a sustainable approach that contributes to decreasing the resistance of antimicrobials and enhancing the bioavailability of first-line drugs for intestinal chronic inflammation and neurodegenerative diseases.

Regionalized analysis of gut barrier components in the small intestine of BALB/c mice following chronic immobilization stress.

BACKGROUND: Microbiota and tight junction proteins (TJPs) are components of the gut barrier, and are considered stress targets that have deleterious effects on intestinal homeostasis. OBJECTIVES: This study aimed to evaluate the effects of chronic immobilization stress on selected small intestine homeostasis parameters. MATERIAL AND METHODS: Female BALB/c mice were divided into a stress group that underwent short-term immobilization for 2 h per day for 4 consecutive days, and a non-stressed control group (n = 6 per group). Proximal and distal small intestine samples were excised to assess colony-forming units per gram (CFU/g) of total bifidobacteria in selective agar plates, luminal albumin was assessed using immune-enzymatic assay, pro-inflammatory cytokines were evaluated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and TJPs (pore-forming, claudin (Cld)-2; pore-sealing, Cld-4; ambiguous, Cld-7, -12 and -15) were assessed with RT-qPCR and western blotting. RESULTS: Compared with the control group, the stress group had lower body weight and energy intake. In the distal region, the stressed mice had lower bifidobacteria count and messenger ribonucleic acid (mRNA) expression of Cld-2, Cld-4 and Cld-12, though they had more albumin and higher interleukin (IL)-6 mRNA expression. Within the proximal region, the stressed mice had higher mRNA expression of tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), IL-6, Cld-7, Cld-12, and Cld-15, along with lower levels of IL-10 and Cld-4. However, mRNA and protein expression of TJPs were discordant. CONCLUSIONS: These findings indicate divergent stress-induced outcomes in the small intestine, evidenced by the elicitation of a pro-inflammatory response and decreased anti-inflammatory response in the duodenum, and by increased albumin transudation and decreased bifidobacterial growth in the distal region.

Outcomes of nicotinic modulation on markers of intestinal IgA antibody response.

Acetylcholine (ACh), as a ligand of nicotinic acetylcholine receptors (nAChRs), plays a key role in the cholinergic anti-inflammatory pathway; however, its role in the immunoglobulin A (IgA) response remains unknown. Therefore, the present study aimed to investigate the role of ACh in the intestinal biomarkers involved in IgA synthesis and the polymeric immunoglobulin receptor (pIgR) involved in IgA transcytosis. Groups of mice were administered GTS-21 (an α7nAChR agonist) or mecamylamine (a non-selective nAChR antagonist) intraperitoneally for 7 days. Intestinal fluids were used for antibody concentration assessment by ELISA, cell suspensions from Peyer's patches and the lamina propria were obtained for flow cytometric analysis of plasma cells, and CD4+ T-cells expressing intracellular transforming growth factor (TGF)-ß and IgA-producing interleukin (IL)-4, -5, -6 and -10, and isolated epithelial cells to determine the levels of pIgR mRNA using reverse transcription-quantitative PCR. Regarding to the untreated control group, the concentration of IgA was reduced in the mecamylamine group and unaltered in the GTS-21 group while IgM levels exhibited no differences; the percentage of IgA+ plasma cells from Peyer's patches and the lamina propria, and the percentage of TGF-ß+/CD4+ T-cells from Peyer's patches were greater in the GTS-21-group. In both treatment groups, the percentages of IgM+ plasma cells and IL-6+/IL-10+ CD4+ T cells were greater in both compartments; pIgR mRNA expression levels decreased in epithelial cells. The percentage of IL-4 CD4+ T-cells were greater in Peyer's patches and lower in the lamina propria in the mecamylamine group, and the percentage of IL-5 CD4+ T-cells in the lamina propria were decreased in both treatment groups. These findings require further examination to address the impact of cholinergic modulation on IgA-transcytosis via pIgR. The present study may be an experimental reference for clinical trials that address the role of nicotinic system in intestinal dysfunctions as postoperative ileus.

Cholecystokinin Outcome on Markers of Intestinal IgA Antibody Response.

Cholecystokinin 8 (CCK8) is an entero-octapeptide that participates in crosstalk with components of intestinal immunity via the CCK receptor (CCKR), but its role in modulation of the IgA response is not fully known under physiological conditions. Male eight-week-old BALB/c mice each were intraperitoneally injected once during 7 days with CCK8, devazapide (CCKR1 antagonist), L365,260 (CCKR2 antagonist) or vehicle (sham group). In intestinal lavages, total and secretory IgA (SIgA) were determined by ELISA; in lamina propria, IgA+ B lymphocytes and IgA+ plasma cells were analyzed by flow cytometry; mRNA levels of polymeric immunoglobulin receptor (pIgR) in epithelial cells and α chain, interleukins (ILs) in lamina propria cells were assessed by qRTPCR. Regarding the sham conditions, IgA+ plasma-cell percentage and IL-2, IL-5, IL-10 and transforming growth factor-ß (TGF-ß) mRNA levels were either increased by CCK8 or decreased by both CCKR antagonists. For IgA/SIgA responses, IL-4/IL-6 mRNA levels were decreased by all drugs and pIgR mRNA was increased by CCK8 and reduced by L365,260. IgA+ B cell percentage and α chain mRNA levels were elicited by CCK8 and L365,260. Data suggested a presumable differential role of CCK/CCKR on the IgA-response; outcome of L365,260 on the elicitation of IgA+ B cells and α chain mRNA needs further examination.

Ascorbic Acid Ameriolates Liver Damage by Myeloperoxidase Oxidative Products in a Hamster Model of Amoebic Liver Abscess.

Entamoeba histolytica is a protozoan-pathogen-causing amoebic liver abscess (ALA). After amoeba establishment in the liver, it causes abundant infiltrate of neutrophils. Liver tissue damage by neutrophils results in part from anti-amoebic oxidative intermediates, including reactive oxygen species (ROS), reactive nitrogen species (RNS), and hypochlorous acid (HOCl), derived from the myeloperoxidase (MPO) enzyme. Ascorbic acid (ASC) is an antioxidant that acts as a scavenger for ROS and NOS-derived free radicals. No previous information regarding the effect of ASC concerning the participation of MPO in an experimental model of ALA in hamsters has been reported. Thus, the aim of the present work was to analyze the effect of ASC on acute ALA development and to measure the activity and gene expression of the MPO enzyme. Hamsters were treated with ASC (800 mg/kg) and then intrahepatically inoculated with E. histolytica trophozoites. Animals were sacrificed at 3, 6, and 12 h post-inoculation (p.i.), and liver samples were collected. The percentage of lesions, amoeba in situ count, MPO activity, and mpo gene expression were ascertained. Compared to ALA hamsters without ASC treatment as the control group (CT), the ALA group treated with ASC had a significant decrease in liver lesions (all p.i. hours) and viable amoeba count (12 h p.i.) and an increase in MPO activity (12 h p.i.) and mpo gene expression (6 h/12 h p.i.). These data suggest that ASC ameliorated liver damage caused by oxidizing products via modulation of mpo expression and activity.

Moderate aerobic exercise on bone quality changes associated with aging and oxidative stress in BALB/c mice.

Exercise encourages active and healthy aging, maintaining functional and physical capabilities. This study aimed to assess the effects of a long-term moderate aerobic exercise protocol on bone microarchitecture and fragility associated with chronic inflammation and oxidative stress in aging. Male BALB/c mice (n = 10 per group) underwent a moderate exercise protocol from 13 weeks to 27 (adulthood age) or 108 weeks of age (elderly age) and were then sacrificed. Age-match sedentary mice were included as a control group. Serum cortisol concentrations were determined by chemiluminescent immunoassay, C-reactive protein (CRP) by a turbidimetric assay, advanced glycation end-products (AGEs) and malondialdehyde (MDA) by fluorescent spectroscopy, and total glutathione (GSH) by colorimetric method. The right femur was dissected formorphometric and densitometricanalysis bycomputerized microtomography (µCT),and biomechanical properties were assessed usinga three-point bending device. Musclefrom the same extremitywas obtained to determine relative mRNA expression ofpro-inflammatory cytokines (TNF-α and IL-6) by RT-qPCR.Statistical differences were evaluated by two-way ANOVA and Holm-Sidak method post hoc with P < 0.05. In elderly mice, moderate exercise increased glutathione levels and microarchitecture complexity but decreased bone fragility and oxidative stress markers, cortisol, and pro-inflammatory cytokines. In conclusion, these results suggest a strong link between a pro-inflammatory state and age-conditioned oxidative stress on bone quality. Thus, on a human scale, moderate aerobic exercise may improve bone quality during aging.

Lactoferrin: A Nutraceutical with Activity against Colorectal Cancer.

Homeostasis in the human body results from the tight regulation of several events, since too little inflammation disrupts the process of tissue repair and remodeling, whereas too much exerts a collateral effect by causing tissue damage with life-threatening consequences. In some clinical conditions, such as inflammatory bowel disease (IBD), inflammation functions as a double-edged sword by either enabling or inhibiting cancer development and progression. Generally, cancer develops through evasion mechanisms that regulate cell growth, causing a high rate of uncontrolled proliferation, and mechanisms for evading cell death, such as apoptosis. Moreover, chronic inflammation is a factor that contributes to colorectal cancer (CRC), as observed in individuals with IBD; all these conditions favor an increased rate of angiogenesis and eventual metastasis. Lactoferrin (Lf) is a mammalian iron-binding multifunctional glycoprotein regarded as a natural compound that up- and downregulates both humoral and cellular components of immunity involved in regulating the inflammatory response and maintaining gut homeostasis. Human and bovine Lf share high sequence homology and have very similar antimicrobial, anti-inflammatory, and immunomodulatory activities. Bovine Lf from milk is considered a safe molecule and is commercially available in large quantities. This review mainly focuses on the regulatory effects of orally administered bovine Lf on the inflammatory response associated with CRC; this approach indicates that CRC is one of the most frequently diagnosed cancers and affects the intestinal tract with high clinical and epidemiologic relevance. Thus, this review may provide foundations for the potential use of bovine Lf alone or as a natural adjunct agent to increase the effectiveness and reduce the side effects of anticancer chemotherapy.

Muscarinic receptors control markers of inflammation in the small intestine of BALB/c mice.

Muscarinic-acetylcholine-receptors (mAChRs) modulate intestinal homeostasis, but their role in inflammation is unclear; thus, this issue was the focus of this study. BALB/c mice were treated for 7 days with muscarine (mAChR/agonist), atropine (mAChR/antagonist) or saline. Small-intestine samples were collected for histology and cytofluorometric assays in Peyer's patches (PP) and lamina propria (LP) cell-suspensions. In LP, goblet-cells/leukocytes/neutrophils/MPO+ cells and MPO/activity were increased in the muscarine group. In PP, IFN-γ+/CD4+ T or IL-6+/CD4+ T cell numbers were higher in the muscarine or atropine groups, respectively. In LP, TNF-α+/CD4+ T cell number was higher in the muscarine group and lower in the atropine.

Lactoferrin and Its Potential Impact for the Relief of Pain: A Preclinical Approach.

Pain is one of the most disabling symptoms of several clinical conditions. Neurobiologically, it is classified as nociceptive, inflammatory, neuropathic and dysfunctional. Opioids and nonsteroidal anti-inflammatory drugs (NSAIDs) are conventionally prescribed for the treatment of pain. Long-term administration of opioids results in the loss of analgesic efficacy, leading to increased dosage, tolerance, and addiction as the main drawbacks of their use, while the adverse effects of NSAIDs include gastric ulcer formation, intestinal bleeding, acute kidney injury, and hepatotoxicity. Lactoferrin is an iron-binding, anti-inflammatory glycoprotein that displays analgesic activities associated, in part, by interacting with the low-density lipoprotein receptor-related protein (LRP), which may result in the regulation of the DAMP-TRAF6-NFκB, NO-cGMP-ATP K+-sensitive channel and opioid receptor signaling pathways. This review summarizes and discusses for the first time the analgesic effects of lactoferrin and its presumable mechanisms based on pre-clinical trials. Given its anti-nociceptive and anti-inflammatory properties, lactoferrin may be used as an adjunct to enhance the efficacy and to decrease the tolerogenic effects of canonical therapeutic drugs prescribed for pain treatment.

Intestinal Homeostasis under Stress Siege.

Intestinal homeostasis encompasses a complex and balanced interplay among a wide array of components that collaborate to maintain gut barrier integrity. The appropriate function of the gut barrier requires the mucus layer, a sticky cushion of mucopolysaccharides that overlays the epithelial cell surface. Mucus plays a critical anti-inflammatory role by preventing direct contact between luminal microbiota and the surface of the epithelial cell monolayer. Moreover, mucus is enriched with pivotal effectors of intestinal immunity, such as immunoglobulin A (IgA). A fragile and delicate equilibrium that supports proper barrier function can be disturbed by stress. The impact of stress upon intestinal homeostasis results from neuroendocrine mediators of the brain-gut axis (BGA), which comprises a nervous branch that includes the enteric nervous system (ENS) and the sympathetic and parasympathetic nervous systems, as well as an endocrine branch of the hypothalamic-pituitary-adrenal axis. This review is the first to discuss the experimental animal models that address the impact of stress on components of intestinal homeostasis, with special emphasis on intestinal mucus and IgA. Basic knowledge from animal models provides the foundations of pharmacologic and immunological interventions to control disturbances associated with conditions that are exacerbated by emotional stress, such as irritable bowel syndrome.

Analysis of the intestinal IgA response in mice exposed to chronic stress and treated with bovine lactoferrin.

Immunoglobulin (Ig) A, an antibody with a pivotal role in gut homeostasis, can be modulated by stress and bovine lactoferrin (bLf). The aim of the present study was to analyze the impact of chronic stress on the IgA response in the small intestine during bLf treatment. Male BALB/c mice (n=6 mice/group) underwent 1 h of chronic stress by immobilization for 7 consecutive days or were left unstressed, and were untreated or treated with bLf (50, 500 or 5,000 µg). Plasma corticosterone expression levels were determined by ELISA. The distal small intestine was dissected to analyze: i) total IgA, secretory IgA and IgG, as well as and specific IgA and IgG antibody levels in the intestinal liquid by ELISA; ii) α­chain and polymeric immunoglobulin receptor (pIgR) protein expression in epithelial cell extracts analyzed by western blotting; iii) the mRNA expression levels of α­/J­chains, pIgR, IL­2, IL­4, IL­5 and IL­6 in whole mucosal samples by reverse transcription­quantitative PCR. Data were analyzed by one­way ANOVA, and the differences were analyzed by the Holm­Sidák post hoc test and were considered significant if P<0.05. Results from the present study revealed the upregulatory effects of chronic stress on the total antibody levels, protein (α­chain; 78­kDa pIgR) and mRNA (α­ and J­chains; pIgR; IL­6) expression levels were restricted by bLf under stress. The effects of chronic stress on the downregulation of IL­2 and IL­4 mRNA expression were not changed by bLf under stress. The corticosterone response in unstressed mice treated with 5,000 µg bLf and the specific­IgG levels in the unstressed and stressed groups treated with bLf at all doses were increased. The findings suggested an effect of bLf in maintaining homeostasis under stress.

Anterior subdiaphragmatic vagotomy decreases the IgA antibody response in the small intestines of BALB/c mice.

To assess the impact of vagotomy on the IgA-response, male BALB/c mice underwent anterior vagotomy or a sham procedure were sacrificed on day 14 post-operation and the proximal and distal small-gut segments were dissected. In intestinal lavages IgA/IgM antibodies were analysed by ELISA; in Peyer's-patches and lamina-propria cell suspensions the intracellular IgA-associated interleukins (ILs) and pro-inflammatory cytokines in CD4+ T cells were analysed by cytofluorometry. Vagotomy reduced the IgA or increased the IgM antibody concentration in both segments and reduced or increased the lamina- propria CD4+ T cell pro-inflammatory cytokine responses in the distal or proximal segments, respectively. Data show the role of the vagus nerve on the IgA response.

Immunity to influenza: Impact of obesity.

Obesity is a health concern that is recognized as a critical factor for vulnerability to influenza A/pdmH1N1 virus infection, with epidemiological and clinical impacts. In humans, obesity induces disturbances in inflammatory and immune responses to the influenza virus and in some cases, this leads to severe complications, with fatal outcomes. Obesity impairs immunity by altering the response of cytokines, resulting in a decrease in the cytotoxic cell response of immunocompetent cells which have a key anti-viral role. Additionally, obesity seems to disturb the balance of endocrine hormones, such as leptin, that affect the interplay between metabolic and immune systems. This contribution focuses on reviewing the current epidemiologic data for the immune response to immunity in obese humans and animal models. In doing so, we aim to provide potential mechanisms to enhance immunity to influenza A/pdmH1N1 virus infection and protective factors in obese people.

The Impact of Lactoferrin on the Growth of Intestinal Inhabitant Bacteria.

Lactoferrin (Lf) is an iron-binding milk glycoprotein that promotes the growth of selected probiotic strains. The effect of Lf on the growth and diversification of intestinal microbiota may have an impact on several issues, including (i) strengthening the permeability of the epithelial cell monolayer, (ii) favoring the microbial antagonism that discourages the colonization and proliferation of enteric pathogens, (iii) enhancing the growth and maturation of cell-monolayer components and gut nerve fibers, and (iv) providing signals to balance the anti- and pro-inflammatory responses resulting in gut homeostasis. Given the beneficial role of probiotics, this contribution aims to review the current properties of bovine and human Lf and their derivatives in in vitro probiotic growth and Lf interplay with microbiota described in the piglet model. By using Lf as a component in pharmacological products, we may enable novel strategies that promote probiotic growth while conferring antimicrobial activity against multidrug-resistant microorganisms that cause life-threatening diseases, especially in neonates.

Impact of chronic immobilization stress on parameters of colonic homeostasis in BALB/c mice.

The intestinal epithelium is a monolayer of cells arranged side­by­side and connected by tight junction (TJ) proteins expressed at the apical extreme of the paracellular membrane. This layer prevents stress­induced inflammatory responses, thus helping to maintain gut barrier function and gut homeostasis. The aim of the present study was to evaluate the effects of chronic immobilization stress on the colonic expression of various parameters of homeostasis. A total of two groups of female BALB/c mice (n=6) were included: A stressed group (short­term immobilization for 2 h/day for 4 consecutive days) and an unstressed (control) group. Colon samples were obtained to detect neutrophils and goblet cells by optical microscopy, TJ protein expression (occludin, and claudin ­2, ­4, ­7, ­12 and ­15) by western blotting, mRNA levels of TJ genes and proinflammatory cytokines [tumor necrosis factor (TNF)­α, interleukin (IL)­1ß, ­6 and ­8] by reverse transcription­quantitative PCR, fecal lactoferrin by ELISA and the number of colony­forming units of aerobic bacteria. Compared with goblet cells in control mice, goblet cells were enlarged and reduced in number in stressed mice, whereas neutrophil cellularity was unaltered. Stressed mice exhibited reduced mRNA expression for all evaluated TJ mRNAs, with the exception of claudin­7, which was upregulated. Protein levels of occludin and all claudins (with the exception of claudin­12) were decreased in stressed mice. Fecal lactoferrin, proinflammatory cytokine mRNA levels and aerobic bacterial counts were all increased in the stressed group. These results indicated that immobilization stress induced proinflammatory and potential remodeling effects in the colon by decreasing TJ protein expression. The present study may be a useful reference for therapies aiming to regulate the effects of stress on intestinal inflammatory dysfunction.

Posterior Subdiaphragmatic Vagotomy Downmodulates the IgA Levels in the Small Intestine of BALB/c Mice.

OBJECTIVE: The posterior vagus nerve trunk innervates the entire small intestine, and elucidating its modulatory role in the IgA response was the aim of this study. METHODS: Two groups of six male BALB/c mice underwent sham or posterior subdiaphragmatic vagotomy and were euthanized on the 14th postoperative day; then, the small intestines were dissected. The intestinal fluid was harvested for antibody analysis by ELISA, and cell suspensions from Peyer's patches and lamina propria were prepared for cytofluorometric analysis of plasma cells and T lymphocytes. The CD4+ T cells were labeled for the intracellular IgA-producing interleukins (ILs)-4, -5, -6, and -10; transforming growth factor (TGF)-ß; and the inflammatory cytokines tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and IL-12. In the intestinal tissue samples, myeloperoxidase (MPO) visualization and the enzymatic activity were assessed by immunohistochemistry and ELISA, respectively. The data were analyzed by Student's t test, and the differences were considered significant at p < 0.05. RESULTS: In the vagotomy group, the IgA levels and the CD4+ T cells labeled with mediators that promote IgA secretion, including IL-4 (only at lamina propria), TNF-α, and IFN-γ, were decreased, whereas the lamina propria IgA+ plasma cells and MPO presence/activity were increased; changes in the IgM levels, IgM+ plasma cells, and CD4+ T cells labeled with TGF-ß, which have a role in class switch recombination, were not observed. CONCLUSION: The downmodulating impact of vagotomy on IgA levels may result from defective IgA secretion without affecting class switch recombination, whereas vagotomy evoked a proinflammatory response regarding MPO. These findings may reflect the role of the vagus nerve on the control of the IgA response in the small intestine.

Lactoferrin and Peptide-derivatives: Antimicrobial Agents with Potential Use in Nonspecific Immunity Modulation.

Lactoferrin (Lf) is a conserved cationic non-heme glycoprotein that is part of the innate immune defense system of mammals. Lf is present in colostrum, milk and mucosal sites, and it is also produced by polymorphonuclear neutrophils and secreted at infection sites. Lf and Lf N-terminus peptide-derivatives named lactoferricins (Lfcins) are molecules with microbiostatic and microbicidal action in a wide array of pathogens. In addition, they display regulatory properties on components of nonspecific immunity, including toll-like receptors, proand anti-inflammatory cytokines, and reactive oxygen species. Mechanisms explaining the ability of Lf and Lfcins to display both up- and down-modulatory properties on cells are not fully understood but result, in part, from their interactions with membrane receptors that elicit biochemical signal pathways, whereas other receptors enable the nuclear translocation of these molecules for the modulation of target genes. The dual role of Lf and Lfcins as antimicrobials and immunomodulators is of biotechnological and pharmaceutical interest. Native Lf and its peptide-derivatives from human and bovine sources, the recombinant versions of the human protein, and their synthetic peptides have potential application as adjunctive agents in therapies to combat infections caused by multi-resistant bacteria and those caused by fungi, protozoa and viruses, as well as in the prevention and reduction of several types of cancer and response to LPS-shock, among other effects. In this review, we summarize the immunomodulatory properties of the unique multifunctional protein Lf and its N-terminus peptides.