Inhibitory effect of isomaltodextrin on tyrosine metabolite production in rat gut microbiota.

We examined the effect of isomaltodextrin (IMD), a soluble dietary fiber, on production of putrefactive products by intestinal bacteria using a tyrosine load test to measure phenol production in IMD-treated rats. We observed a significant increase in phenol and p-cresol concentrations in rats administered with only tyrosine, but not for rats co-administered tyrosine and IMD. To elucidate the mechanism of this effect, we analyzed the intestinal microbiota in each group and found that although IMD had no direct effect on the proportion of bacteria known to produce phenols, it did alter the balance of intestinal microbiota. The results suggested that changes in the intestinal microbiota composition reduced the metabolic capacity for tyrosine and in turn suppressed production of phenol or p-cresol, putrefactive products in the intestine.

Determination of the point resolution of high-resolution transmission electron microscope using the through-focus technique.

From the viewpoint of evaluating the instrumental performance of high-resolution electron microscopy (HREM), the Scherzer condition was investigated using information theory. As a result, the optimum defocus amount Δf can be expressed based on [Formula: see text] , and the formula [Formula: see text] is obtained. Furthermore, a procedure for measuring point resolution using the through-focus technique is developed, and a new method for determining the spherical aberration coefficient using the variance of Δf is introduced in the procedure.

Erratum: Attenuation of postprandial blood glucose in humans consuming isomaltodextrin: carbohydrate loading studies.

[This corrects the article DOI: 10.1080/16546628.2017.1325306.].

Propolis prevents diet-induced hyperlipidemia and mitigates weight gain in diet-induced obesity in mice.

We examined the hypolipidemic effect of propolis in a mouse obesity model induced by a high fat-diet. C57BL/6N mice were fed a high-fat diet ad libitum and given propolis extract intragastrically at 0 mg/kg (control), 5 mg/kg or 50 mg/kg twice daily for 10 d. Compared with mice in the control group, mice in the propolis extract-administrated groups displayed a reduction in all of the following parameters: body weight gain, weight of visceral adipose tissue, liver and serum triglycerides, cholesterol, and non-esterified fatty acids. Real-time polymerase chain reaction analysis of the liver showed down-regulation of mRNA expression associated with fatty acid biosynthesis, including fatty acid synthase, acetyl-CoA carboxylase alpha, and sterol regulatory element binding protein in the propolis-administrated mice. Subsequently, obese C57BL/6N mice that had been administered a high-fat diet were given propolis extract at 0 mg/kg (control), 2.5 mg/kg or 25 mg/kg for 4 weeks. The propolis extract treated mice showed a decrease in weight gain, a reduction of serum non-esterified fatty acids, and lipid accumulation in the liver. These results suggest that propolis extract prevented and mitigated high-fat diet-induced hyperlipidemia by down-regulating the expression of genes associated with lipid metabolism.

Lactosucrose inhibits body fat accumulation in rats by decreasing intestinal lipid absorption.

Lactosucrose (LS, 4(G)-beta-D-galactosylsucrose) is a non-digestible oligosaccharide, and the consumption of LS selectively increases the proportion of intestinal bifidobacteria. We examined in this study the hypolipidemic potential of LS. An oral triolein tolerance test on rats indicated that LS reduced the elevation of serum triglyceride (TG) and free fatty acids (FFA). Furthermore, LS inhibited the enzymatic digestion of triolein by pancreatic lipase in vitro. NMR spectroscopy showed that LS formed an intermolecular complex with triolein. The long-term consumption of a diet containing 5% LS for 8 weeks significantly decreased the weight of abdominal adipose tissue when compared with that of the control group. Thus, LS may reduce adipose tissue accumulation by inhibiting intestinal lipid absorption via a direct interaction with TG.

Prophylactic effects of isomaltodextrin in a Balb/c mouse model of egg allergy.

The aim of this study was to evaluate the potential effects of isomaltodextrin (IMD), a dietary saccharide polymer derived from enzymatically produced from starch, on the ability to alter immune response (IR) bias to hen egg ovalbumin (Ova) induced allergic inflammation in mice. Groups of Balb/c mice were pre-treated with various doses of IMD in drinking water (1.0, 2.5, and 5.0% w/v) for 6 weeks and subsequently sensitized to the Ova together with continuous administration of IMD. To evaluate changes in immune response bias, immunoglobulin isotype-associated antibody activity, concentrations of type 1 and 2 cytokines and the percentage of T-regulatory cells (T-regs) in blood were measured. Clinical signs of allergy were assessed after oral challenge with Ova. Treatment with IMD did not significantly alter the frequency of clinical signs, however there was a trend in the overall reduction of clinical signs. Effect on IR bias was observed in the treatment groups as reflected by reduction in a type 1-biased phenotype as evident by decrease in isotype-specific IgE, IgG and increase in IL-12 cytokine production and a high proportion of T-regs. This study revealed that IMD could be a useful prophylactic candidate for alteration of allergic IR bias in mice and an immune-stimulator for reducing egg induced allergic reactions.

Anti-Inflammatory Activity of Isomaltodextrin in a C57BL/6NCrl Mouse Model with Lipopolysaccharide-Induced Low-Grade Chronic Inflammation.

：The purpose of this study was to identify the anti-inflammatory activity and mechanism of isomaltodextrin (IMD) in a C57BL/6NCrl mouse model with lipopolysaccharide (LPS)-induced systemic low-grade chronic inflammation and the effect on inflammation-induced potential risk of metabolic disorders. Pre-treatment of IMD decreased the production of pro-inflammatory mediators, TNF-α and MCP-1, and stimulated the production of the anti-inflammatory mediator, adiponectin by increasing the protein expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) in the white adipose tissues. IMD administration reduced plasma concentrations of endotoxin, decreased macrophage infiltration into adipocytes, and increased expression of mucin 2, mucin 4, and the tight junction protein claudin 4. These results suggest that IMD administration exerted an anti-inflammatory effect on mice with LPS-induced inflammation, potentially by decreasing circulating endotoxin, suppressing pro-inflammatory mediators and macrophage infiltration, or by improving mucus or tight junction integrity. IMD exerted protein expression of insulin receptor subset-1 (IRS-1). IMD alleviated the disturbance of gut microflora in LPS-treated mice, as the number of B. bifidum, L. casei, and B. fragilis increased, and E. coli and C. difficile decreased, when compared to LPS-treated mice. The analysis of short chain fatty acids (SCFAs) further supported that the concentrations of acetic and butyric acids were positively correlated with IMD, as well as the number of beneficial bacteria. This study provides evidence that IMD possesses anti-inflammatory properties and exerts beneficial functions to prevent systemic low-grade chronic inflammation and reduces the risk of developing insulin resistance and associated metabolic diseases.

Low-dose performance of parallel-beam nanodiffraction.

We evaluate the low-dose performance of parallel nano-beam diffraction (NBD) in the transmission electron microscope as a method for characterizing radiation sensitive materials at low electron irradiation dose. A criterion, analogous to Rose's, is established for detecting a diffraction spot with desired signal-to-noise ratio. Our experimental data show that a dose substantially lower than in high-resolution bright-field imaging is sufficient to determine structure and orientation of individual nanoscale objects embedded in amorphous matrix. In an instrument equipped with a cold field-emission gun it is possible to form a probe with sub-3 nm diameter and sub-0.3 mrad convergence angle with sufficient beam current to record a diffraction pattern with less than 0.2 s acquisition time. The interpretation of NBD patterns is identical to that of selected area diffraction patterns. We illustrate the physical principles underlying good low-dose performance of NBD by means of a phase grating. The electron irradiation dose needed to detect a diffraction peak in NBD is found proportional to 1/N2, where N is the number of lattice planes contributing to the peak.

Effects of isomaltodextrin in postprandial lipid kinetics: Rat study and human randomized crossover study.

Isomaltodextrin (IMD) is a novel dietary fiber-like polysaccharide: a type of α-glucan produced from starch using enzymes derived from microorganisms. The results of cohort studies show that dietary fiber can prevent cardiovascular disorders caused by lifestyle-related diseases such as metabolic syndrome. Inhibition of excess fat absorption by dietary fiber is known to be one of the mechanisms, and it is also known that the actions of dietary fiber vary depending on factors such as its structure or origin. Thus, we investigated the inhibitory actions of IMD on fat absorption, and analyzed its mechanism of action. In rats, the absorption of fat given by gavage was significantly lower at 1, 2, and 6 hours after IMD administration than after vehicle administration. In humans, IMD was associated with a lesser increase in blood triglycerides in subjects whose blood triglycerides were otherwise apt to rise. We also found by in vitro emulsion studies that IMD, which had no effect on digestive enzyme activity or emulsion formation, stabilized the micro size micelle by inducing enlarged micelle particle size and increased zeta potential. In conclusion, the mechanism of inhibition of fat absorption by IMD may be a delay in micelle particles accessing the intestinal epithelium through changes in the surface structure and the physical properties of the micelle particles.

Effects of dietary lactosucrose (4G-beta-D-galactosylsucrose) on the IgE response in mice.

In this study, we examined the effects of dietary lactosucrose (LS, a non-digestible oligosaccharide) on the IgE response in mice immunized with ovalbumin (OVA)/alum. In addition to IgG1 and IgG2a responses, the anti-OVA IgE response in mice fed LS diets was dose-dependently suppressed, as compared with the control mice, while the serum total IgG levels were comparable. Moreover, dietary LS feeding inhibited antigen-specific IgE and IgG1 productions even after a second immunization. Regarding with cytokine production, when stimulated in vitro with OVA, splenocytes obtained from LS-fed mice produced a similar level of IFN-gamma, and lower levels of IL-4 and IL-5, as compared with the control mice. But IL-10 production by OVA-stimulated splenocytes was augmented in LS-fed mice, suggesting that IL-10 producing cells are responsible for the immunoregulatory effect of LS. Our findings indicate the further possibility that dietary LS supplementation can be used to prevent IgE-mediated allergic diseases.

Intervention of Isomaltodextrin Mitigates Intestinal Inflammation in a Dextran Sodium Sulfate-Induced Mouse Model of Colitis via Inhibition of Toll-like Receptor-4.

Isomaltodextrin (IMD), a highly branched α-glucan, is a type of resistant starch. Earlier studies have indicated that polysaccharides could prevent inflammation and can be effective in reducing the complications of chronic gastrointestinal diseases such as inflammatory bowel disease (IBD). Therefore, the aim of the present study was to evaluate the anti-inflammatory effect of IMD in dextran sodium sulfate (DSS)-induced colitis in a mouse model. IMD (0.5, 1.0, 2.5, and 5.0% (w/v)) was given orally for 23 days to female Balb/c mice, and then 5% DSS was administered to induce colitis (from day 15 onward to the end of the trial). IMD could not prevent DSS-induced weight loss or colon shortening. However, IMD could reduce inflammatory cytokines, TNF-α and IL-6, in the colon. Gene expression indicated the tendency of IMD to suppress pro-inflammatory cytokines IL-1ß, MCP-1, and IL-17 and to increase an anti-inflammatory cytokine, IL-10. Further study revealed that the anti-inflammatory action of IMD mediates through inhibition of the expression of Toll-like receptor-4.

Attenuation of postprandial blood glucose in humans consuming isomaltodextrin: carbohydrate loading studies.

Background: Isomaltodextrin (IMD) is a novel highly branched α-glucan and its function as a soluble dietary fiber is expected. Objective: The goal of this study was to evaluate the effects of IMD on postprandial glucose excursions in healthy people and to make the mechanism clear. Design: Twenty-nine subjects ingested a solution containing maltodextrin (MD) or sucrose with or without IMD. Fourteen subjects ingested a solution containing glucose with or without IMD. Blood glucose concentrations were then compared between the groups. Furthermore, in vitro digestion, inhibition of digestive enzymes, and glucose absorption tests were conducted. Results: IMD attenuated blood glucose elevation in the subjects with blood glucose excursions at the high end of normal following the ingestion of MD or sucrose or glucose alone. This effect of 5 g IMD was most clear. IMD was digested partially only by small intestinal mucosal enzymes, and maltase and isomaltase activities were weakly inhibited. Furthermore, IMD inhibited the transport of glucose from mucosal side to serosal side. Conclusions: IMD attenuated postprandial blood glucose, after the ingestion of MD or sucrose or glucose. As one of the mechanism, it was suggested that IMD inhibited the absorption of glucose on small intestinal mucosal membrane.

mAgK114 suppresses lymphocyte infiltration into epidermis in the picryl chloride-induced atopic dermatitis-like skin lesions of NC/Nga mice.

BACKGROUND: We have previously shown that when mouse AgK114 (mAgK114, a glycosylphosphatidylinositol anchored membrane-associated protein) is applied to the wound area, the inflammatory responses in the early recovery phase of damaged tissue are enhanced and wound closure is accelerated. This suggests that mAgK114 has an important effect on skin wound repairing. MATERIALS AND METHODS: Whether mAgK114 supresses the development, in NC/Nga mice, of atopic dermatitis (AD)-like skin lesions induced by repeated application of 2,4,6-trinitrochlorobenzene (picryl chloride, PiCl) was examined under specific pathogen-free conditions. RESULTS: Histopathologically, the application of mAgK114-ointment to the PiCl-treated NC/Nga mice remarkably suppressed severe lymphocytic infiltration into the epidermis, although total skin severity scores, histological changes in hypertrophy, erosion and infiltration of inflammatory cells into the corium and subcutaneous tissues were comparable between the mAgK114-treated group of mice and the control group. CONCLUSION: Our results suggest that mAgK114 would be beneficial for the treatment of atopic dermatitis by suppressing severe lymphocytic infiltration into the epidermis.

Design of a 300-kV gas environmental transmission electron microscope equipped with a cold field emission gun.

A new in situ environmental transmission electron microscope (ETEM) was developed based on a 300 kV TEM with a cold field emission gun (CFEG). Particular caution was taken in the ETEM design to assure uncompromised imaging and analytical performance of the TEM. Because of the improved pumping system between the gun and column, the vacuum of CFEG was largely improved and the probe current was sufficiently stabilized to operate without tip flashing for 2-3 h or longer. A high brightness of 2.5 × 10(9) A/cm(2) sr was measured at 300 kV, verifying the high quality of the CFEG electron beam. A specially designed gas injection-heating holder was used in the in situ TEM study at elevated temperatures with or without gas around the TEM specimen. Using this holder in a 10 Pa gas atmosphere and specimen temperatures up to 1000°C, high-resolution ETEM performance and analysis were achieved.

Oral administration of a T cell epitope inhibits symptoms and reactions of allergic rhinitis in Japanese cedar pollen allergen-sensitized mice.

Although the concept of a T cell epitope in specific immunoprophylaxis was proposed more than a decade ago, it had not been well demonstrated since then that a T cell epitope inhibits symptoms and reactions of allergic disease in animal models. In this study, we have established a system to evaluate symptoms and reactions of allergic rhinitis in mice, and investigated whether oral administration of a T cell epitope relieves sensitized mice of allergic rhinitis. P2-246-259 (RAEVSYVHVNGAKF) is a BALB/c mouse T-cell epitope of Cry j 2, which is a major Japanese cedar (Cryptomeria japonica) pollen allergen. Mice were administered orally with 200 microg/animal of P2-246-259 four times within 2 weeks before sensitization, and sensitized intranasally with Cry j 2 twice. Of the cardinal symptoms of allergic rhinitis, we assessed sneezing and airway obstruction, but could not estimate rhinorrhea or pruritus. Sneezing frequency was significantly increased by challenge with Cry j 2. Concerning allergic reactions, vascular permeability of the nasal mucosa in the early phase and hyperreactivity to histamine in the late phase were also exacerbated by the challenge. These symptoms and reactions of allergic rhinitis were significantly inhibited by oral administration of P2-246-259. These results indicate utility of mice as models for allergic rhinitis; furthermore, the effects of P2-246-259 on allergic rhinitis imply that oral administration of a T cell epitope is a promising approach for specific immunoprophylaxis.

Oral administration of royal jelly inhibits the development of atopic dermatitis-like skin lesions in NC/Nga mice.

We have shown previously that in addition to IL-4, IL-5 and IL-10, antigen-specific interferon-gamma (IFN-gamma) production by spleen cells from ovalbumin (OVA)/Alum-immunized mice is inhibited by the administration of royal jelly (RJ). Since it has been shown that both Th1 and Th2 cytokines play pathogenic roles in the generation of atopic dermatitis (AD), we have examined whether RJ suppresses the development of AD-like skin lesions in NC/Nga mice induced by repeated application of picryl chloride (PiCl) under specific pathogen-free (SPF) conditions. Oral administration of RJ to the PiCl-treated NC/Nga mice inhibited the development of AD-like skin lesions in these mice as exemplified by the significant decrease in the total skin severity scores and the decrease in hypertrophy, hyperkeratosis, and infiltration of the epidermis and corium by inflammatory cells. IFN-gamma production by spleen cells from PiCl-treated NC/Nga mice in response to TNP-KLH was partially but significantly inhibited by the oral administration of RJ, while IFN-gamma production by Con A-stimulated spleen cells was not affected. Since inducible nitric oxide (NO) synthase (iNOS)-derived NO has been suggested as an important immunoregulatory mediator in inflammatory autoimmune diseases, we have also examined the expression of iNOS in the dorsal skin lesions of PiCl-treated NC/Nga mice. Interestingly, the expression of iNOS was significantly increased in the skin lesions of RJ-administered mice compared with those of control PBS-administered mice. Thus, our results suggest that RJ suppresses the development of AD-like skin lesions in PiCl-treated NC/Nga mice, possibly by a combination of down-regulating TNP-specific IFN-gamma production and up-regulating iNOS expression.

Major royal jelly protein 3 modulates immune responses in vitro and in vivo.

We have recently shown that royal jelly has potent antiallergic properties in a mouse model of immediate hypersensitivity. However, it is still unclear which components of royal jelly exhibit antiallergic activity. In this study, we have screened for antiallergic factors in royal jelly based on inhibition of IL-4 production by anti-CD3 stimulated spleen cells derived from OVA/alum-immunized mice. Using a series of column chromatographies, we purified a 70 kDa glycoprotein, major royal jelly protein 3 (MRJP3), that suppresses IL-4 production. In in vitro experiments, MRJP3 suppressed the production of not only IL-4 but also that of IL-2 and IFN-gamma by T cells concomitant with inhibition of proliferation. The MRJP3-mediated suppression of IL-4 production was also evident when lymph node cells from OVA/alum-immunized mice were stimulated with OVA plus antigen presenting cells. We next examined the purified suppressive factor on OVA/alum-induced allergic responses in mice. Interestingly, in spite of the antigenicity of MRJP3 itself as an extraneous foreign protein, intraperitoneal administration of MRJP3 inhibited serum anti-OVA IgE and IgG1 levels in immunized mice. In addition, heat-treated soluble MRJP3 treatment reduced its antigenicity while maintaining its inhibitory effects on antibody responses to OVA. These results indicate that MRJP3 can exhibit potent immunoregulatory effects in vitro and in vivo. Furthermore, considering the intriguing immunomodulatory effects of MRJP3, it may be of clinical significance to design MRJP3-derived antiallergic peptides by identifying the associated polypeptide regions.

Intraoral administration of a T-cell epitope peptide induces immunological tolerance in Cry j 2-sensitized mice.

Sublingual immunotherapy using allergen-derived peptides is feasible as a novel specific immunotherapy, but its efficacy has not yet been demonstrated in either humans or animals. In addition, it remains obscure whether the oral immune system is involved in the mechanism of sublingual immunotherapy. Here, we show that the intraoral administration of the T-cell epitope peptide P2-246-259 derived from Cry j 2, a major Japanese cedar (Cryptomeria japonica) pollen allergen, to Cry j 2-sensitized mice induces immunological tolerance, and that ex vivo lymph node cell proliferation to P2-246-259 and Cry j 2 was inhibited. In addition, intraoral administration was shown to be superior to intragastric administration in terms of tolerance induction, suggesting that the oral immune system contributes to the induction of immunological tolerance. Therefore, the significant efficacy of sublingual immunotherapy using a peptide on allergen-specific T-cells was demonstrated in animals, and this may be potentiated by the oral mucosal immune system.

Three T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen antigens, retain their immunogenicity and tolerogenicity in a linked peptide.

It has been demonstrated in detail that administration of a dominant T-cell determinant to animals induces activation or immunological tolerance of T cells. However, it has not been determined whether multiple T-cell determinants, when integrated into a single peptide, retain their potential to induce T-cell activation and tolerance. We prepared a synthetic peptide comprising three T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen antigens, and investigated the immunogenicity and tolerogenicity of each T-cell determinant in the linked peptide by means of lymph node cell proliferation assays using mice. Lymph node cells from mice immunized with each of the three T-cell determinants proliferated against the linked peptide in a dose-dependent manner, similar to that of the immunized peptide. Lymph node cells from mice immunized with the linked peptide proliferated against all of the three T-cell determinants. In addition, the degree of proliferation against the three T-cell determinants occurred according to their original immunogenicity, as observed in the native protein antigens. Oral administration of the linked peptide to mice before they were immunized with Cry j 1 and Cry j 2 inhibited lymph node cell proliferation against the three T-cell determinants, depending on the dose of the linked peptide administered. In conclusion, it was demonstrated that three T-cell determinants retain their original immunogenicity and tolerogenicity in a linked peptide comprising them.

DNA vaccine using invariant chain gene for delivery of CD4+ T cell epitope peptide derived from Japanese cedar pollen allergen inhibits allergen-specific IgE response.

To establish a new immunotherapy for type I allergic diseases without allergic side effects, we attempted to develop a DNA vaccine encoding both a CD4+ T cell epitope site in a major Japanese cedar pollen allergen (Cry j 2) and an invariant chain (Ii) for the delivery of the epitope peptide into the MHC class II loading pathway. We constructed a plasmid DNA encoding the Ii mutant either by replacement of the core CLIP (class II-associated invariant chain peptide) with a peptide corresponding to the major Cry j 2 CD4+ T cell epitope in BALB/c mice, designated as p247-258 (pCPCJ2), or by fusion of the Ii with p247-258 at the C terminus (pIiCJ2). As expected, repeated inoculation of BALB/c mice with pCPCJ2 or pIiCJ2 induced no antibody response to Cry j 2. In contrast, intramuscular inoculation of BALB/c mice with pCPCJ2 or pIiCJ2 predominantly induced p247-258-specific Th1 cells, resulting in the inhibition of IgE response to subsequent Cry j 2 injections. Our results demonstrated that the plasmid DNA encoding the CD4+ T cell epitope and Ii can induce epitope-specific CD4+ T cell responses in vivo and the potential to regulate type I allergic reaction without allergic side effects.