Dietary nucleic acids promote a shift in Th1/Th2 balance toward Th1-dominant immunity

Targeting Aging and Longevity with Exogenous Nucleotides (TALENTs): Rationale, Design, and Baseline Characteristics from a Randomized Controlled Trial in Older Adults

Nucleotides (NTs), important biomolecules involved in numerous cellular processes, have been proposed as potential candidates for anti-aging interventions. However, whether nucleotides can act as an anti-aging supplement in older adults remains unclear. TALENTs is a randomized, double-blinded, placebo-controlled trial that evaluates the efficacy and safety of NTs as an anti-aging supplement in older adults by exploring the effects of NTs on multiple dimensions of aging in a rigorous scientific setting. Eligible community-dwelling adults aged 60-70 years were randomly assigned equally to two groups: nucleotides intervention group and placebo control group. Comprehensive geriatric health assessments were performed at baseline, 2-months, and 4-months of the intervention. Biological specimens were collected and stored for age-related biomarker testing and multi-omics sequencing. The primary outcome was the change from baseline to 4 months on leukocyte telomere length and DNA methylation age. The secondary aims were the changes in possible mechanisms underlying aging processes (immunity, inflammatory profile, oxidative stress, gene stability, endocrine, metabolism, and cardiovascular function). Other outcomes were changes in physical function, body composition and geriatric health assessment (including sleep quality, cognitive function, fatigue, frailty, and psychology). In the RCT, 301 participants were assessed for eligibility and 122 were enrolled. Participants averaged 65.65 years of age, and were predominately female (67.21%). All baseline characteristics were well-balanced between groups, as expected due to randomization. The majority of participants were pre-frailty and had at least one chronic condition. The mean scores for physical activity, psychological, fatigue and quality of life were within the normal range. However, nearly half of the participants still had room for improvement in cognitive level and sleep quality. This TALENTs trial will represent one of the most comprehensive experimental clinical trials in which supplements are administered to elderly participants. The findings of this study will contribute to our understanding of the anti-aging effects of NTs and provide insights into their potential applications in geriatric healthcare.

Effect of gut microbiota early in life on aggressive behavior in mice

Recent reports have indicated that gut microbiota modulates the responses to stress through the microbiota-gut-brain axis in mice, suggesting a connection between gut microbiota and brain function. We hypothesized that the gut microbiota early in life would have an effect on aggressiveness, and examined how gut microbiota affect aggressive behaviors in mice. BALB/c mice were housed in germ-free (GF) and ex-germ-free (Ex-GF) isolators. An aggression test was performed between castrated and a non-castrated mice at 8 weeks of age; the mice were allowed to confront each other for 10 min in strictly contamination-free environments. To evaluate aggressive behavior related to gut microbiota, we orally administered diluted Ex-GF mouse feces to the offspring of GF mice at 0, 6, and 10 weeks. GF mice showed more aggression than Ex-GF mice. Furthermore, GF mice who were administered feces of the Ex-GF group at 0-week-old were less aggressive than the GF mice. These findings suggested that the gut microbiota in the early stages of development was likely to have an effect on aggressiveness. Maintenance of healthy gut microbiota early in life can affect the mitigation of aggressive behavioral characteristics throughout the lifetime.

The Efficacy of Oral Nutritional Intervention in Malnourished Cancer Patients: a Systemic Review

Cancer is currently a leading cause of deaths worldwide and the number of new cases is growing rapidly in both, developed and developing countries. Nutritional management during and after cancer treatment affects treatment efficacy and patient quality of life (QOL). This review systemically examined the effect of oral nutritional interventions on nutritional and clinical outcomes in cancer patients. We especially focused on outcomes such as nutritional status indices, immune-associated biochemical markers, and QOL assessments to provide insights on the applicability of different outcomes. A total of 28 papers were selected for systematic review. The nutritional composition of oral nutritional supplements (ONS), outcome measures, and efficacy of the oral nutritional interventions were summarized and discussed. Most ONS contain 1 or more functional components in addition to basic nutrients. Each study used various outcome measures and significant efficacy was observed for a limited number of measures. Nutritional status indices, QOL measures, and the duration of hospital stay improved in about 40% of the studies. One or more markers of immune function and inflammatory responses were improved by ONS in 65% of the selected studies. These results suggest that appropriate use of ONS may be an ideal way to improve treatment efficacy; however, additional intervention trials are required to confirm these findings.

Probiotic Dahi containing Lactobacillus acidophilus and Bifidobacterium bifidum modulates immunoglobulin levels and cytokines expression in whey proteins sensitised mice

BACKGROUND

Cow milk allergy is the most common food allergy in children. So far, no effective treatment is available to prevent or cure food allergy. This study investigated whether orally administrated probiotics could suppress sensitisation in whey proteins (WP)-induced allergy mouse model. Two types of probiotic Dahi were prepared by co-culturing Dahi bacteria (Lactococcus lactis ssp. cremoris NCDC-86 and Lactococcus lactis ssp. lactis biovar diacetylactis NCDC-60) along with selected strain of Lactobacillus acidophilus LaVK2 and Bifidobacterium bifidum BbVK3. Mice were fed with probiotic Dahi (La-Dahi and LaBb-Dahi) from 7 days before sensitisation with WP, respectively, in addition to milk protein-free basal diet, and control group received no supplements.

RESULTS

Feeding of probiotic Dahi suppressed the elevation of whey proteins-specific IgE and IgG response of WP-sensitised mice. In addition, sIgA levels were significantly (P < 0.001) increased in intestinal fluid collected from mice fed with La-Dahi. Production of T helper (Th)-1 cell-specific cytokines, i.e. interferon-γ (IFN-γ), interleukin (IL)-12, and IL-10 increased, while Th2-specific cytokines, i.e. IL-4 decreased in the supernatant of cultured splenocytes collected from mice fed with probiotic Dahi as compared to the other groups. Moreover, the splenic mRNA levels of IFN-γ, interleukin-10 were found to be significantly increased, while that of IL-4 decreased significantly in La-Dahi groups, as compared to control groups.

CONCLUSION

Results of the present study indicate that probiotic Dahi skewed Th2-specific immune response towards Th1-specific response and suppressed IgE in serum. Collectively, this study shows the potential use of probiotics intervention in reducing the allergic response to whey proteins in mice. © 2015 Society of Chemical Industry.

A nucleoprotein-enriched diet suppresses dopaminergic neuronal cell loss and motor deficit in mice with MPTP-induced Parkinson's disease

Parkinson's disease (PD) is an obstinate progressive neurodegenerative disease and characterized by locomotor impairment and dopaminergic neuronal degeneration in the substantia nigra pars compacta (SNc). We examined in here the dietary effect of nucleoprotein (NP) extracted from salmon soft roe on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-injected PD-like mice model to prevent the symptom as an alternative medicine. Male C57/BL6 mice were given either an artificially modified NP-free diet (NF) or NF supplied with 1.2% NP for 1 week. Then, mice were injected intraperitoneally four times with 20 mg/kg MPTP. Seven days later, locomotor activity was examined, and the brains were immunostained with tyrosine hydroxylase (TH) and Iba1 antibodies. Moreover, in situ detection of superoxide anion (O2(-)) and gene expression of mitochondrial electron transfer chain gene, Cox8b was evaluated in midbrains. NP-fed animals showed significantly reduced locomotor impairment and an increased number of TH-positive cells in the SNc compared with NF animals. The NP-fed animals also showed reduced lower levels of O2(-) and up-regulation of Cox8b levels and Iba1 immunoreactivity, suggesting that inflammation and oxidative stress were suppressed and mitochondrial impairment was relieved in these animals. Supplementation of the diet with NP may serve as a useful preventive measure to slow the onset of PD.

Commensal microbiota modulate murine behaviors in a strictly contamination-free environment confirmed by culture-based methods

BACKGROUND

There is increasing evidence suggesting the existence of an interaction between commensal microbiota, the gut and the brain. The aim of this study was to examine the influence of commensal microbiota on the host behaviors in a contamination-free environment, which was verified by culture-based methods.

METHODS

Open-field and marble-burying tests were used to analyze anxiety-like behaviors and locomotor activity in gnotobiotic BALB/c mice with a common genetic background in a sterile isolator. The monoamine levels in several regions of the brain were measured in germfree (GF) mice and commensal fecal microbiota-associated mice (EX-GF).

KEY RESULTS

A 24-h exposure to the environment outside the sterile isolators rendered GF mice less anxious than those not contaminated, while there was no change in the locomotion. EX-GF mice, the gnotobiotic mice with normal specific pathogen-free microbiota, were less anxious and active than GF mice using open-field and marble-burying tests. The norepinephrine, dopamine, and serotonin turnover rates were higher in the EX-GF mice than in the GF mice in most regions of the brain, suggesting that monoaminergic neurotransmission might increase in the EX-GF mice comparing the GF mice. Monoassociation with Brautia coccoides reduced the anxiety level, but it did not affect the locomotor activity. In contrast, colonization with Bifidobacterium infantis decreased the locomotor activity, while having little effect on the anxiety level.

CONCLUSIONS & INFERENCES

These results strongly support the current view that gut microorganisms modulate brain development and behavior.

DNA-fragments are transcytosed across CaCo-2 cells by adsorptive endocytosis and vesicular mediated transport

Dietary DNA is degraded into shorter DNA-fragments and single nucleosides in the gastrointestinal tract. Dietary DNA is mainly taken up as single nucleosides and bases, but even dietary DNA-fragments of up to a few hundred bp are able to cross the intestinal barrier and enter the blood stream. The molecular mechanisms behind transport of DNA-fragments across the intestine and the effects of this transport on the organism are currently unknown. Here we investigate the transport of DNA-fragments across the intestinal barrier, focusing on transport mechanisms and rates. The human intestinal epithelial cell line CaCo-2 was used as a model. As DNA material a PCR-fragment of 633 bp was used and quantitative real time PCR was used as detection method. DNA-fragments were found to be transported across polarized CaCo-2 cells in the apical to basolateral direction (AB). After 90 min the difference in directionality AB vs. BA was >10³ fold. Even undegraded DNA-fragments of 633 bp could be detected in the basolateral receiver compartment at this time point. Transport of DNA-fragments was sensitive to low temperature and inhibition of endosomal acidification. DNA-transport across CaCo-2 cells was not competed out with oligodeoxynucleotides, fucoidan, heparin, heparan sulphate and dextrane sulphate, while linearized plasmid DNA, on the other hand, reduced transcytosis of DNA-fragments by a factor of approximately 2. Our findings therefore suggest that vesicular transport is mediating transcytosis of dietary DNA-fragments across intestinal cells and that DNA binding proteins are involved in this process. If we extrapolate our findings to in vivo conditions it could be hypothesized that this transport mechanism has a function in the immune system.

Critical role of gut microbiota in the production of biologically active, free catecholamines in the gut lumen of mice

There is increasing interest in the bidirectional communication between the mammalian host and prokaryotic cells. Catecholamines (CA), candidate molecules for such communication, are presumed to play an important role in the gut lumen; however, available evidence is limited because of the lack of actual data about luminal CA. This study evaluated luminal CA levels in the gastrointestinal tract and elucidated the involvement of gut microbiota in the generation of luminal CA by comparing the findings among specific pathogen-free mice (SPF-M), germ-free mice (GF-M), and gnotobiotic mice. Substantial levels of free dopamine and norepinephrine were identified in the gut lumen of SPF-M. The free CA levels in the gut lumen were lower in GF-M than in SPF-M. The majority of CA was a biologically active, free form in SPF-M, whereas it was a biologically inactive, conjugated form in GF-M. The association of GF-M with either Clostridium species or SPF fecal flora, both of which have abundant β-glucuronidase activity, resulted in the drastic elevation of free CA. The inoculation of E. coli strain into GF-M induced a substantial amount of free CA, but the inoculation of its mutant strain deficient in the β-glucuronidase gene did not. The intraluminal administration of DA increased colonic water absorption in an in vivo ligated loop model of SPF-M, thus suggesting that luminal DA plays a role as a proabsorptive modulator of water transport in the colon. These results indicate that gut microbiota play a critical role in the generation of free CA in the gut lumen.

The role of nucleotides in the immune and gastrointestinal systems: potential clinical applications

Nucleotides are low molecular weight biological molecules key to biochemical processes. Sources include de novo synthesis, recovery via salvage mechanisms, and dietary intakes. Although endogenous production serves as the main nucleotide source, evidence suggests that exogenous sources are essential to immune competence, intestinal development, and recovery. Dietary nucleotides serve a marked role in rapidly proliferating cells where they are necessary for optimal function. Accordingly, dietary nucleotides are deemed conditionally essential in the presence of various physiological stresses, including growth and development, recovery from injury, infection, and certain disease states. Clinical studies that evaluated nutrition formulations of nucleotides in combination with other specific nutrient substances demonstrated improved clinical outcomes in patients characterized as critically ill, injured, immune suppressed, or with chronic gastrointestinal conditions. However, conclusions regarding specific benefits of nucleotides are limited. Scientific substantiation of nucleotide supplementation in infant formula has been reported to improve the maturation and development of the intestinal tract as well as immune function. All medical nutrition products except for one immune-modulating formulation are devoid of nucleotides. In an effort to build on this, the current review presents the data to support potential clinical applications for nucleotides in enteral nutrition that may contribute to improved outcomes in physiologically stressed patients.

Nucleotides enhance the secretion of interleukin 7 from primary-cultured murine intestinal epithelial cells

Our previous studies showed that dietary nucleotides fed to mice enhanced the secretion of interleukin 7 (IL-7) and transforming growth factor beta (TGF-beta) from intestinal epithelial cells (IECs). To explore whether nucleotides influence IECs directly to enhance the secretion of the cytokines or not, the effects of nucleotides added in vitro on the cytokine secretion from primary-cultured murine IECs were examined. When the mixture of nucleotide 5'-monophosphates (CMP, GMP, IMP, and UMP) or individual nucleotide 5'-monophosphates were added to the primary culture of IECs derived from BALB/c mice, the secretion of IL-7, but not that of TGF-beta, was increased significantly. Addition of nucleotides to the culture did not alter the number of the IECs. Secretion of IL-6 and granulocyte-macrophage colony-stimulating factor, which are known to be secreted from IECs, was not enhanced by the addition of nucleotides. These results demonstrate that nucleotides can affect IECs directly to enhance the secretion of IL-7, and suggest that the increased secretion of TGF-beta from IECs by dietary nucleotides was due to indirect effects of the nucleotides, which may affect intestinal microflora or cells other than IECs that in turn influence the cytokine secretion of IECs.

Dietary nucleotides increase the mucosal IgA response and the secretion of transforming growth factor beta from intestinal epithelial cells in mice

We have investigated the influence of dietary nucleotides on the intestinal immune system in ovalbumin (OVA)-specific T-cell receptor (TCR) transgenic mice (OVA-TCR Tg mice). When mice were supplied with water supplemented with 2% OVA ad libitum, the faecal OVA-specific immunoglobulin A (IgA) level significantly increased in those fed a nucleotide-supplemented diet (NT(+) diet) compared with those fed a nucleotide-free control diet (NT(-) diet). In the NT(+) diet-fed mice, secretion of transforming growth factor beta (TGF-beta), which is an isotype-specific switch factor for IgA, from intestinal epithelial cells (IECs) was significantly increased. Furthermore, an increased proportion of intestinal intraepithelial lymphocytes (IELs) bearing gammadelta TCR (TCRgammadelta(+) IELs) and increased secretion from IECs of interleukin 7 (IL-7), which is essential for the development of TCRgammadelta(+) IELs, were also observed in OVA-TCR-Tg mice fed the NT(+) diet, as we previously demonstrated using BALB/c mice (Nagafuchi et al., Biosci. Biotechnol. Biochem. 64: 1459-65 (2000)). Considering that TCRgammadelta(+) T cells and TGF-beta are important for an induction of the mucosal IgA response, our results suggest that dietary nucleotides augment the mucosal OVA-specific IgA response by increasing the secretion of TGF-beta from IECs and the proportion of TCRgammadelta(+) IELs.

Dietary deoxynucleic acid induces type 2 T-helper immune response through toll-like receptor 9 in mice

BACKGROUND

It has been shown that dietary nucleotides modulate immune response. Due to their unique properties in immune responses, nucleotides are used as immunonutrition in the field of clinical nutrition.

AIM OF THE STUDY

In this study, we examined the effect of dietary deoxynucleic acid (DNA) on antigen (Ag)-specific immune response in ovalbumin (OVA)-immunized BALB/c mice and determined the mechanism using toll-like receptor 9 (TLR9) knock-out (KO) mice.

METHODS

BALB/c or TLR9 KO mice were fed control and 1% DNA diets and immunized with OVA. Spleen cells from OVA-immunized mice were stimulated with OVA in vitro, and the contents of IFN-γ and IL-4 in supernatants were measured by an ex vivo system. CD11c(+) dendritic cells were purified, and ability of cytokine induction to CD4(+) cells was examined.

RESULTS

The level of OVA-specific IL-4 production in the DNA group was significantly higher than that in the control group. In contrast, the level of OVA-specific IFN-γ production in the DNA group was lower than that in the control group. The DNA diet decreased Ag-specific IL-4 production and enhanced Ag-specific IFN-γ production in TLR9 KO mice. CD11c(+) DCs from mice fed the DNA diet had a greater ability than CD11c(+) DCs from mice fed the control diet to induce the production of IL-4 from DO11.10 CD4(+) T cells.

CONCLUSIONS

Dietary DNA increases Ag-specific IL-4 production and decreases IFN-γ production through a TLR9-dependent pathway. CD11c(+) dendritic cells are target cells in dietary DNA-induced immune regulation.

Nucleoprotein Diet Ameliorates Arthritis Symptoms in Mice Transgenic for Human T-Cell Leukemia Virus Type I (HTLV-1)

Because rheumatoid arthritis (RA), an autoimmune disease, the patients often recognize side-effects due to the medication, alternative therapeutic strategies might potentially offer a clinical advantage. We evaluated the effect of nucleoprotein from salmon soft roe on animal model of arthritis. Mice transgenic for human T-cell leukemia virus type I (HTLV-1 Tg) were divided into three experimental groups and supplemented on either nucleoprotein-free (nonNP), or 0.6% or 1.2% nucleoprotein mixed (NP0.6 or NP1.2) diet for 3 months. The mice were evaluated arthritis by morphology, and measured with rheumatoid factor (RF). Moreover, macrophages and oxidative metabolites were assessed in the ankle and/or serum. Anti-oxidative potentials in nucleoprotein were determined with biological anti-oxidative potential (BAP) test, and electron spin resonance (ESR) analysis. NonNP-diet HTLV-1 Tg mice increased an arthritis symptoms and RF. The symptoms were ameliorated in NP-diet groups. Macrophages detected by F4/80 staining, and oxidative metabolites in the serum and/or joints were clearly decreased in 1.2% NP-diet HTLV-1 Tg mice. Nucleoprotein and DNA-nucleotide, but less protamine, had direct anti-oxidative potency with BAP test and/or ESR in vitro. These observations suggest that dietary nucleoprotein ameliorates arthritis symptoms in HTLV-1 Tg mice and offers hope as an alternative treatment for this debilitating medical condition.

Dietary nucleotides protect thymocyte DNA from damage induced by cyclophosphamide in mice

The effects of dietary nucleotides on thymocyte DNA damages induced by cyclophosphamide (CP) in mice were examined. First, phase I experiment was conducted to determine the optimal timing of detecting thymocyte DNA damages induced by CP (150 mg/kg body weight) in mice. Thymocyte DNA damages was determined at 6, 12, 18, 24 h by single-cell gel electrophosphoresis assay (comet assay) after intraperitoneal injection of CP. The levels of DNA damage at 6, 12, 18, 24 h were all significantly higher than that of the control group (p < 0.01). The highest level of DNA damage appeared at 18 h and then decreased at 24 h. Therefore, 18 h was selected to determine DNA damages induced by CP in subsequent experiments. In phase II experiment, 30 male KunMing mice were divided into three treatments: negative control (NC), positive control (PC) and nucleotides group (NG). Mice in NC and PC were fed nucleotide-free diet, and mice in NG were fed nucleotide-supplemented diet (supplemented with 0.25% nucleotides, a mixture containing equal amounts of AMP, CMP, GMP and UMP). Mice in PC and NG groups were injected with CP (150 mg/kg body weight) at 21 days. DNA damage in thymocytes was evaluated at 18 h after CP treatment. The results indicate that dietary nucleotides do not affect the weights of the thymus and the spleen, or their organ indices (p > 0.05), but significantly decrease the percentage of comet cells and comet tail sizes (p < 0.01). This study demonstrates that dietary nucleotides could reduce the level of thymocyte DNA damage induced by CP in mice.

Dietary nucleotides and human immune cells. II. Modulation of PBMC growth and cytokine secretion

OBJECTIVE

The immune system is dependent on purines and pyrimidines as building blocks for DNA and RNA synthesis to enable rapid cell proliferation and protein synthesis. Emerging evidence suggests that dietary nucleotides optimize immune function. We investigated whether growth and function of human immune cells were affected by an exogenous source of nucleotides during specific antigen challenge.

METHODS

Peripheral blood mononuclear cells from healthy individuals (n = 10) were stimulated with influenza virus antigen and either DNA sodium from fish soft roe (DNA), RNA from bakers yeast (Saccharomyces cerevisiae) (RNA), 2' deoxyadenosine 5'-monophosphate sodium (dAMP), 2' deoxycytidine 5'-monophosphate sodium (dCMP), 2' deoxyguanosine 5'-monophosphate sodium (dGMP), 2' deoxyuridine 5'-monophosphate sodium (dUMP) or thymidine sodium (TMP). Growth effects were ascertained by measuring the amount of tritium-labeled thymidine, incorporated into cell DNA. Cell function was measured by detection of IFN-gamma, TNF-alpha and IL-10 production.

RESULTS

Specific nucleotide derivatives alone did not affect the growth of healthy peripheral blood mononuclear cells. However, the nucleotide derivatives influenced immune cell growth and cytokine secretion when cocultured with specific antigen. DNA, RNA, dAMP, dCMP and dUMP increased influenza virus antigen induced immune cell proliferation. In contrast dGMP and TMP inhibited the antigen-induced growth response. RNA and dAMP cocultured with virus antigen significantly increased peripheral blood mononuclear cell secretion of IFN-gamma, IL-10 and TNF-alpha. DNA increased virus antigen-induced immune cell secretion of IFN-gamma only, whereas dUMP significantly increased secretion of IL-10 only. dGMP completely inhibited virus-triggered IFN-gamma secretion, whereas TMP did not change the virus induced secretion pattern of measured cytokines.

CONCLUSION

Nucleotide derivatives affect growth and function of specific virus antigen-stimulated human immune cells in vitro.

Dietary nucleotides and human immune cells. II. Modulation of PBMC growth and cytokine secretion

OBJECTIVE

The immune system is dependent on purines and pyrimidines as building blocks for DNA and RNA synthesis to enable rapid cell proliferation and protein synthesis. Emerging evidence suggests that dietary nucleotides optimize immune function. We investigated whether growth and function of human immune cells were affected by an exogenous source of nucleotides during specific antigen challenge.

METHODS

Peripheral blood mononuclear cells from healthy individuals (n = 10) were stimulated with influenza virus antigen and DNA-Na+ from fish soft roe, RNA from bakers yeast (Saccharomyces cerevisiae), 2'deoxyadenosine 5'-monophosphate sodium, 2'deoxycytidine 5'-monophosphate sodium, 2'deoxyguanosine 5'-monophosphate sodium, or 2'deoxyuridine 5'-monophosphate disodium. Growth effects were ascertained by measuring the amount of tritium-labeled Thymidine 5'-monophosphate sodium incorporated into cell DNA. Cell function was measured by detection of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha, and interleukin-10 production.

RESULTS

Specific nucleotide derivatives alone did not affect the growth of healthy peripheral blood mononuclear cells. However, the nucleotide derivatives influenced immune cell growth and cytokine secretion when cocultured with specific antigen. DNA, RNA, deoxyadenosine monophosphate, deoxycytidine monophosphate, and deoxyuridine monophosphate increased influenza virus antigen-induced immune cell proliferation. In contrast, deoxyadenosine monophosphate and thymosine monophosphate inhibited the antigen-induced growth response. RNA and deoxyadenosine monophosphate cocultured with virus antigen significantly increased peripheral blood mononuclear cell secretion of IFN-gamma, interleukin-10, and tumor necrosis factor-alpha. DNA increased virus antigen-induced immune cell secretion of IFN-gamma only, whereas deoxyuridine monophosphate significantly increased secretion of interleukin-10 only. Deoxyguanosine monophosphate completely inhibited virus-triggered IFN-gamma secretion, whereas thymosine monophosphate did not change the secretion pattern of measured cytokines.

CONCLUSION

Nucleotide derivatives affect growth and function of specific virus antigen-stimulated human immune cells in vitro.

Oral administration of Bifidobacterium bifidum G9-1 suppresses total and antigen specific immunoglobulin E production in mice

Recent studies have suggested that oral bacteriotherapy with probiotics might be useful in the management of allergic diseases. We investigated the effect of oral administration of Bifidobacterium bifidum G9-1 (BBG9-1) on immunoglobulin (Ig) E production in BALB/c mice. Live BBG9-1 was orally administered to mice for 2 weeks from 1 week before ovalbumin (OVA)-immunization. The treatment of BBG9-1 significantly reduced serum total IgE level. In addition, BBG9-1 significantly and largely reduced the serum level of OVA-specific IgE without lowering of the specific IgG1 and increasing of the specific IgG2a. We also examined T helper type (Th) 1 and Th2 cytokine production from OVA-immunized splenocytes by restimulation with OVA in vitro. Productions of interferon (IFN)-gamma, interleukin (IL)-4 and IL-5 from the splenocytes of mice given BBG9-1 were weaker than those of control mice. We conclude that oral administration of BBG9-1 selectively and powerfully suppresses total and antigen specific IgE production in mice. It is suggested that BBG9-1 is useful for the prophylactic treatment in IgE-dependent allergic diseases.

Dietary nucleic acid and intestinal microbiota synergistically promote a shift in the Th1/Th2 balance toward Th1-skewed immunity

BACKGROUND

Intestinal microbiota are known to play an important role in the establishment of oral tolerance, thereby protecting the organism from food allergies. Dietary intake of nucleic acid (NA) is also reported to have such an anti-allergic effect; however, one unsolved question is whether or not dietary NA would act through a process of toll-like receptor 9 signaling activated by DNA containing a CpG motif, a well-known sequence leading to immunostimulatory activity. In this study, we focused on the question of whether the addition of dietary NA lacking CpG motifs would allow continued modulation of the Th1/Th2 balance.

METHODS

Germ free (GF) and Bifidobacterium-infantis-monoassociated BALB/c mice were maintained on either an NA-free casein diet or on an NA-supplemented casein diet for 4 weeks. Thereafter, both the in vivo anti-casein antibody levels and in vitro splenocyte cytokine secretion pattern were evaluated.

RESULTS

Feeding with a casein diet elicited a substantial increase in the serum anti-casein-specific IgG1, IgG2a, and IgE levels of GF mice fed the NA free-diet. The in vitro cytokine production profile showed that enhanced IL-4 production in the GF mice fed the NA free-diet was markedly reduced by the supplementation with dietary NA in both the GF and B.-infantis-monoassociated mice. In addition, IFN-gamma secretion increased in the B.-infantis-reconstituted mice fed the diet containing NA.

CONCLUSIONS

These results suggest that dietary intake of NA devoid of CpG motifs may prevent the development of allergies via acceleration of Th1-dominant immunity.

Postnatal microbial colonization programs the hypothalamic-pituitary-adrenal system for stress response in mice

Indigenous microbiota have several beneficial effects on host physiological functions; however, little is known about whether or not postnatal microbial colonization can affect the development of brain plasticity and a subsequent physiological system response. To test the idea that such microbes may affect the development of neural systems that govern the endocrine response to stress, we investigated hypothalamic-pituitary-adrenal (HPA) reaction to stress by comparing germfree (GF), specific pathogen free (SPF) and gnotobiotic mice. Plasma ACTH and corticosterone elevation in response to restraint stress was substantially higher in GF mice than in SPF mice, but not in response to stimulation with ether. Moreover, GF mice also exhibited reduced brain-derived neurotrophic factor expression levels in the cortex and hippocampus relative to SPF mice. The exaggerated HPA stress response by GF mice was reversed by reconstitution with Bifidobacterium infantis. In contrast, monoassociation with enteropathogenic Escherichia coli, but not with its mutant strain devoid of the translocated intimin receptor gene, enhanced the response to stress. Importantly, the enhanced HPA response of GF mice was partly corrected by reconstitution with SPF faeces at an early stage, but not by any reconstitution exerted at a later stage, which therefore indicates that exposure to microbes at an early developmental stage is required for the HPA system to become fully susceptible to inhibitory neural regulation. These results suggest that commensal microbiota can affect the postnatal development of the HPA stress response in mice.

Nutritional support in critical care

Despite the key role of nutrition in health and the almost universal use of supplemental feeding in the ICU, there is a lack of high-quality evidence to guide clinical practice. Enteral nutrition is superior to TPN in almost all circumstances and most patients in the ICU can be fed successfully by this route. There is little evidence to support the use of special feeds and the role of immunonutrients remains unproven. Nutritional support cannot completely prevent the adverse effects of catabolic illness and overfeeding should be avoided.

Nucleoprotamine diet derived from salmon soft roe protects mouse hippocampal neurons from delayed cell death after transient forebrain ischemia

The nutritional benefits of nucleoprotamine (NP), the main component of fish soft roe, have been rarely addressed. In the present study, the preventive effect of oral supplements of nucleoprotamine and its derivatives, DNA and protamine (PT), extracted from salmon soft roe, on survival rate and hippocampal cell death induced by transient brain ischemia, was evaluated in mice. Artificially formulated nucleoprotamine-free (NF) diet with/without nucleoprotamine, DNA or protamine was fed orally. One week after commencement of respective diets, animals were subjected to transient brain ischemia, which was performed by common carotid artery (CCA) occlusion for 25 (severe) or 15 min (mild). After severe ischemia, the survival rate of the NF group was lower than that in the group fed standard diet or NP. Morphological changes in the hippocampal CA1 region were estimated 48 h after mild ischemia. The NP and PT groups significantly decreased the neuronal damage compared with the NF group. The number of cell death in the DNA group, however, was affected similar to that of the NF group. Our data suggests that the nucleoprotamine content in salmon soft roe could be a useful nutritional resource for the prevention of cell damage caused by ischemia such as those occurring with cerebral and/or heart infarction.

Developmental immunology: clinical application to allergy-immunology

BACKGROUND

An increase in prevalence of allergic diseases has been seen at an unprecedented rate in many countries throughout the world. Associated with this increase in allergic disease has been a disturbing increase in morbidity and mortality of such diseases as asthma despite the availability of several new therapeutic agents over the past 2 to 3 decades. The search for both environmental factors, eg, new allergens, as well as biologic markers of genetic susceptibility, eg, respiratory viruses, has yielded considerable promise for an explanation for this rising prevalence of allergic disease.

OBJECTIVE

To present a central unifying hypothesis based upon recent knowledge concerning the developing human immune system and its interaction with external environmental factors, particularly viral infections, as a basis for a clearer understanding of the changing faces of the allergic diseases throughout the lifespan of the individual.

DATA SOURCES

English language articles were selected from PubMed, as well as selected abstracts that would have immediate, practical clinical implications.

RESULTS

Review of the current literature strongly suggests a relationship between delayed acquisition of Th1 function in the allergy-prone infant, not only as a predictive marker of susceptibility to the development of allergic disease but also as an explanation for the unique vulnerability of these infants to viral infection, eg, bronchiolitis. Furthermore, viral infection during early development in the allergy-prone infant appears to facilitate allergic sensitization in early infancy. This interesting triad of immune deficiency, viral infection, and atopic genetic susceptibility may provide a basis for early detection of allergic disease and may offer new intervention strategies for the prevention of allergic and infectious disease in the young infant.

An oral introduction of intestinal bacteria prevents the development of a long-term Th2-skewed immunological memory induced by neonatal antibiotic treatment in mice

BACKGROUND

Recent epidemiological studies indicate that antibiotic use in infancy may be associated with an increased risk of developing atopy. Our previous work on animals demonstrated that kanamycin use during infancy promotes a shift in the Th1/Th2 balance towards a Th2-dominant immunity.

OBJECTIVE

The first purpose of this study is to clarify whether or not the supplementation of intestinal bacteria can reverse such a Th2-skewed response induced by neonatal antibiotic use. The second objective is to elucidate the contribution of genetic factors to antibiotic-induced immune-deviation.

METHODS

BALB/c or C57BL/6 mice at 3 weeks of age were orally administered 600 microg/day of kanamycin sulphate for seven consecutive days. Thereafter, the mice were inoculated with one type of intestinal bacterial species: Enterococcus faecalis, Lactobacillus acidophilus or Bacteroides vulgatus. Blood samples were collected 10 weeks after the cessation of kanamycin treatment, and the effect of the kanamycin treatment on Th1/Th2 balance was evaluated based on in vivo antibody levels.

RESULTS

A kanamycin-induced elevation of the serum IgE levels was reversed by the supplementation with Enterococcus faecalis, and to a lesser extent by that with Lactobacillus acidophilus. The IgE/IgG2a ratio in the mice supplemented with Enterococcus faecalis significantly decreased in comparison with that in the kanamycin-treated mice without any bacterial supplementation, while such a ratio was enhanced in the mice inoculated with Bacteroides vulgatus. No antibiotic-induced Th2-skewed response was seen in C57BL/6 mice that are genetically biased towards Th1-dominant immunity.

CONCLUSION

These results suggest that adequate probiotic intervention after antibiotic treatment may improve the intestinal ecosystem, and thereby prevent the Th2-shifted immunity induced by neonatal antibiotic use. In addition, the difference of genetic backgrounds also contributes to such an antibiotic-induced Th2-skewed response.

CpG motifs in bacterial DNA and their immune effects

Unmethylated CpG motifs are prevalent in bacterial but not vertebrate genomic DNAs. Oligodeoxynucleotides (ODN) containing CpG motifs activate host defense mechanisms leading to innate and acquired immune responses. The recognition of CpG motifs requires Toll-like receptor (TLR) 9, which triggers alterations in cellular redox balance and the induction of cell signaling pathways including the mitogen activated protein kinases (MAPKs) and NF kappa B. Cells that express TLR-9, which include plasmacytoid dendritic cells (PDCs) and B cells, produce Th1-like proinflammatory cytokines, interferons, and chemokines. Certain CpG motifs (CpG-A) are especially potent at activating NK cells and inducing IFN-alpha production by PDCs, while other motifs (CpG-B) are especially potent B cell activators. CpG-induced activation of innate immunity protects against lethal challenge with a wide variety of pathogens, and has therapeutic activity in murine models of cancer and allergy. CpG ODN also enhance the development of acquired immune responses for prophylactic and therapeutic vaccination.

Costimulatory molecules in the developing human gastrointestinal tract: a pathway for fetal allergen priming

BACKGROUND

Antigen-specific responses can be detected in umbilical cord blood mononuclear cells. The fetal immune system must therefore attain a level of maturity compatible with the initiation of such responses as well as be exposed to antigen.

OBJECTIVE

We sought to assess the expression of costimulatory molecules in fetal gut and the presence of cytokines in amniotic fluid at this time as a preliminary analysis of the suitability of the fetal gut as a site of antigen priming during intrauterine life.

METHODS

Human fetal gut was analyzed for cells expressing costimulatory molecules through use of immunohistochemistry. Amniotic fluid was studied by ELISA, for cytokines regulating the nature of the response, and as a source of the common dietary antigen ovalbumin.

RESULTS

MHC class II--positive cells were abundant over the period examined (11-24 weeks of gestation), other surface antigens showing spatial and temporal variation in expression. From 11 to 14 weeks of gestation, CD68-positive and CD40-positive cells, like MHC class II--positive cells, were present throughout the lamina propria; few CD3-positive cells (T cells) were observed. With the emergence of lymphoid aggregates (14-16 weeks), CD83-positive cells (dendritic cells) and CD20-positive cells (B cells) could be detected in fetal gut; however, expression was restricted to the lymphoid aggregates. In contrast, MHC class II, CD40, and CD68 continued to be expressed in the lamina propria. CD28-positive cells were also evident from 14 weeks of gestation, occurring throughout the lamina propria and lymphoid aggregates; this corresponded to the increasing numbers of CD3-positive cells. The occasional CD86-positive, CD40L-positive, or CTLA4-positive cell could be seen in or around lymphoid aggregates after 14 weeks of gestation. Lymphoid follicles forming after 16 weeks of gestation contained MHC class II--positive, CD83-positive, CD20-positive, CD40-positive, CD86-positive, CD3-positive, CD28-positive, CD40L-positive, and CTLA4-positive cells. MHC class II--positive, CD40-positive, CD68-positive, CD3-positive, and CD28-positive cells continued to be present in the lamina propria at this time. At all times studied, CD14 was not expressed in the lamina propria or lymphoid follicles. Prostaglandin E(2), TGF beta(1), and IL-10 dominated the amniotic fluid cytokine milieu, and ovalbumin was also detectable in amniotic fluid from 3 of 26 women who had detectable circulating levels.

CONCLUSION

Of the costimulatory molecules studied, CD40 was the most abundant. However, both of the ligand families studied (CD40-CD40L and CD86-CD28/CD152) could provide the costimulatory signals required for the initiation of antigenspecific reactivity in the gastrointestinal tract of the human fetus as early as 16 weeks of gestation. The cytokine milieu would favor the development of T(H)2-type reactivity to antigens, such as ovalbumin, that are present at this time.

Nucleotides as immunomodulators in clinical nutrition

Dietary nucleotides, like glutamine, have attracted attention as a key ingredient missing from nutritional formulae for many years. They are the building blocks of tissue RNA and DNA and of ATP and their presence in breast milk has stimulated research in babies which has indicated that supplementation of infant formula milk leads to improved growth and reduced susceptibility to infection. Animal studies have confirmed some of these data. In particular, dietary nucleotides modulate immune function, promote faster intestinal healing and have trophic effects on the intestine of parenterally-fed rats which are similar to those resulting from glutamine supplementation, but at much lower intakes. Nucleotide supplementation has also been shown to improve some aspects of tissue recovery from ischaemia/reperfusion injury or radical resection. There is, however, a fundamental paradox. The intestine and liver possess powerful homeostatic mechanisms which degrade intake of purines and pyrimidines (i.e. salvage) and replace it with de novo synthesised output. It is possible that peripheral tissues receive only small amounts of nucleotides of dietary origin. Previously, nucleotides have been proposed as being conditionally-essential nutrients that provide an adequate supply of purines and pyrimidines for nucleic acid synthesis in neonates or in the stressed patient. This review explores this puzzle in the light of recent data from nutritional studies and from research into purinergic signalling in the intestine, heart and cells of the immune system. We propose that dietary nucleotides should be considered within a pharmacological and metabolic framework.

The immunologic basis for intestinal food allergy

There has been considerable recent broadening of basic concepts of intestinal food allergy, in particular the importance of non-IgE-mediated mechanisms. The traditional emphasis on IgE-mediated allergy now appears inappropriate in light of current studies of the basic mechanisms of oral tolerance to dietary antigen and of increasing recognition of the requirement for early infectious challenge in the prevention of allergic sensitization. This major change in emphasis has been forced both by basic scientific studies and by recognition of novel patterns of food allergic disease within the pediatric population, in which rapid increase in food-allergic sensitization has been noted in the last decade and previously rare phenomena such as multiple food allergies and sensitization of exclusively breast-fed infants to antigens eaten by the mother have become commonplace. It is thus emerging that the possession of exaggerated IgE responses may not be the direct cause of food allergic sensitization but may ensure that such sensitization is clinically obvious. Those without such immediate responses have a complex of symptoms, including diet-responsive eczema and a marked disturbance of intestinal motility. The clear demographic links with socioeconomic privilege and relative protection from gastrointestinal infarctions concord with recent murine data suggesting an obligatory input from innate immune responses to the gut flora in the establishment of oral tolerance.