Measuring the health effects of food by metabolomics.

Metabolomics of human biological fluids or tissues is used to discover markers for diseases by comparing the metabolome of the patients against healthy individuals. Ultimately, these markers can be used in drug discovery to determine how medications normalize (at least in part) the human metabolome at specific disease stages to homeostatic. Likewise, the health effects of food can be studied. Even metabolomics of the food can be combined with metabolomics of the treated patients to correlate compounds from food with measurable health effects from clinical studies. Various chemometric analyses of these metabolomics data are used to identify markers for diseases and to obtain evidence for health effects. This review discusses recent researches (published from 2013 to 2021) on whether specific dietary intervention to humans suffering from metabolic disorders may improve their pathological status. The scope is limited to those associated with major lifestyle diseases such as diabetes, obesity, and cardiovascular diseases, for which food is thought may have detrimental as well as beneficial effects on human health. It includes metabolites characterization of different biological samples such as the human serum/plasma, urine, saliva, feces, or ileal fluid. Whether the study results supported the claimed health benefits and whether the research was conducted with appropriate study design, was criticized.

Oligomeric Procyanidins Interfere with Glycolysis of Activated T Cells. A Novel Mechanism for Inhibition of T Cell Function.

Procyanidins, which are flavonoids that are found in a variety of plant species, reduce or prevent immune disorders, such as allergy and autoimmune diseases, through an unknown mechanism. In the present study, we investigated the effects of procyanidins on the T cell receptor (TCR)-mediated responses of CD4⁺ T cells in vitro. Apple procyanidins strongly suppressed the proliferation of splenic CD4⁺ T cells that were stimulated by an anti-CD3ε antibody, as well as splenocytes stimulated by antigen, but did not alter interleukin (IL)-2 secretion from these cells. Furthermore, we found that oligomeric procyanidins strongly suppressed, in a degree of polymerization dependent manner, the proliferation of activated CD4⁺ T cells, as well as their production of effector cytokines, including glycolysis associated-cytokines, without affecting IL-2 secretion. Additionally, we investigated the inhibitory effects of oligomeric procyanidins on the glycolytic activity of activated CD4⁺ T cells. We show that pentameric procyanidin suppressed L-lactate production and glucose uptake in activated CD4⁺ T cells. These results suggest that oligomeric procyanidins suppress the functions of activated CD4⁺ T cells by interfering with glycolysis.

Distinct human and mouse membrane trafficking systems for sweet taste receptors T1r2 and T1r3.

The sweet taste receptors T1r2 and T1r3 are included in the T1r taste receptor family that belongs to class C of the G protein-coupled receptors. Heterodimerization of T1r2 and T1r3 is required for the perception of sweet substances, but little is known about the mechanisms underlying this heterodimerization, including membrane trafficking. We developed tagged mouse T1r2 and T1r3, and human T1R2 and T1R3 and evaluated membrane trafficking in human embryonic kidney 293 (HEK293) cells. We found that human T1R3 surface expression was only observed when human T1R3 was coexpressed with human T1R2, whereas mouse T1r3 was expressed without mouse T1r2 expression. A domain-swapped chimera and truncated human T1R3 mutant showed that the Venus flytrap module and cysteine-rich domain (CRD) of human T1R3 contain a region related to the inhibition of human T1R3 membrane trafficking and coordinated regulation of human T1R3 membrane trafficking. We also found that the Venus flytrap module of both human T1R2 and T1R3 are needed for membrane trafficking, suggesting that the coexpression of human T1R2 and T1R3 is required for this event. These results suggest that the Venus flytrap module and CRD receive taste substances and play roles in membrane trafficking of human T1R2 and T1R3. These features are different from those of mouse receptors, indicating that human T1R2 and T1R3 are likely to have a novel membrane trafficking system.

Effect of Lacto-N-biose I on the Antigen-specific Immune Responses of Splenocytes.

We examined the effect of lacto-N-biose I (LNB) on Antigen (Ag)-specific responses of immune cells. LNB exposure in vitro suppressed Ag-specific Interleukin (IL)-4 secretion of mouse splenocytes significantly. However, IL-4 secretion from CD4(+) T cells stimulated with anti-CD3ε did not changed significantly with LNB exposure. Additionally, Ag-specific Th1 cytokines did not change. Therefore LNB might suppress Ag-specific IL-4 through modification of Ag-presenting cells (APCs) in a manner independent of Th1-type immune development.

Identification of 4-hydroxy-2-nonenal-histidine adducts that serve as ligands for human lectin-like oxidized LDL receptor-1.

LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1) is an endothelial scavenger receptor that is important for the uptake of OxLDL (oxidized low-density lipoprotein) and contributes to the pathogenesis of atherosclerosis. However, the precise structural motifs of OxLDL that are recognized by LOX-1 are unknown. In the present study, we have identified products of lipid peroxidation of OxLDL that serve as ligands for LOX-1. We used CHO (Chinese-hamster ovary) cells that stably express LOX-1 to evaluate the ability of BSA modified by lipid peroxidation to compete with AcLDL (acetylated low-density lipoprotein). We found that HNE (4-hydroxy-2-nonenal)-modified proteins most potently inhibited the uptake of AcLDL. On the basis of the findings that HNE-modified BSA and oxidation of LDL resulted in the formation of HNE-histidine Michael adducts, we examined whether the HNE-histidine adducts could serve as ligands for LOX-1. The authentic HNE-histidine adduct inhibited the uptake of AcLDL in a dose-dependent manner. Furthermore, we found the interaction of LOX-1 with the HNE-histidine adduct to have a dissociation constant of 1.22×10(-8) M using a surface plasmon resonance assay. Finally, we showed that the HNE-histidine adduct stimulated the formation of reactive oxygen species and activated extracellular-signal-regulated kinase 1/2 and NF-κB (nuclear factor κB) in HAECs (human aortic endothelial cells); these signals initiate endothelial dysfunction and lead to atherosclerosis. The present study provides intriguing insights into the molecular details of LOX-1 recognition of OxLDL.

Fiber-based Bessel beams with controllable diffraction-resistant distance.

We experimentally generate n=0 Bessel beams via higher-order cladding mode excitation with a long period fiber grating. Our method allows >99% conversion efficiency, wide or narrow conversion bandwidth, and accurate control of the number of rings in the beam. This latter property is equivalent to tuning the beam cone angle and allows for control of width and propagation distance of the center spot. We generate Bessel-like beams from LP(0,5) to LP(0,15) cladding modes and measure their propagation-invariant characteristics as a function of mode order, which match numerical simulations and a simple geometric model. This yields a versatile tool for tuning depth of focus out of fiber tips, with potential uses in endoscopic microscopy.

An in vitro effect of coffee on the antigen-specific immune responses of naïve splenocytes.

Coffee is a globally consumed beverage with potential health benefits. However, there are few reports about the effects of coffee on immunological functions. We previously reported that in an allergic mouse model, coffee intake prevented allergy development through augmentation of interleukin (IL)-12p40. In order to investigate the anti-allergic activity of coffee, we examined the effect of coffee on antigen (Ag)-specific responses of immune cells in vitro. Coffee treatment suppressed proliferation and IL-2 secretion of mouse splenocytes in the same way as splenocytes from mice administered coffee orally. However, IL-12p40 secretion decreased significantly as a result of in vitro coffee treatment, which was contrary to the results obtained from experiments of mice administered coffee orally. Therefore, modification associated with oral administration might influence the anti-allergic activity of coffee.

Continuous orally administered coffee enhanced the antigen-specific Th1 response and reduced allergic development in a TCR-transgenic mice model.

Coffee is a globally consumed beverage. Although recent studies have suggested that coffee reduced the risk of lifestyle-related diseases, there are few studies regarding allergic response. This study investigates the effects of orally administered coffee (91 ml/kg/d) on allergic responses using a T cell receptor (TCR)-transgenic DO11.10 mouse allergic model. Splenocytes from coffee-administered naïve mice increased antigen (Ag)-specific interleukin (IL)-12p40 secretion. When Ag sensitization and coffee administration were concurrently performed, the splenocytes from coffee-administered mice showed a decrease of IL-2 and an increase of IL-12p40 secretion. The Ag-specific cutaneous response and serum IgE level were reduced in coffee-administered mice, although, after establishing the allergy, coffee administration did not suppress the allergic reaction. These results suggest that coffee could induce a Th1-type response of the immune system and prevent an allergy developing. Further studies on the optimum dose, cultivar differences, and roasted degree need to be undertaken.

Orally administered bisphenol A disturbed antigen specific immunoresponses in the naïve condition.

Bisphenol A [2,2-bis(4-hydoxyphenyl)propane; BPA] is an endocrine disrupter widely used in polycarbonate plastics and epoxy resins. We investigated the effects of orally administered BPA on antigen-specific responses of the naïve immune system.BPA was orally administered to T cell receptor transgenic mice, and the antigen-specific responses of immune cells were investigated. Administered BPA moderately reduced interleukin (IL)-2, 4, and interferon (IFN)-gamma secretion and increases in IgA and IgG2a production.Additionally, it was found that orally administered BPA increased antigen-specific IFN-gamma production of T cells and modified whole antigen presenting cells (APCs) to suppress antigen-specific cytokine production from T cells. These findings suggest that BPA can augment the Th1-type responses of naïve immune systems, though the bioavailability of orally administered BPA was low in our experiments.

Effect of dietary fat on skin reactivity against histamine, Th1 and Th2 cytokine levels and some serum parameters in mice.

Changes in diet may be associated with the increase in allergic disease; change to high-calorie and high-fat diets may be a factor. In this study our objective was to determine skin reactivity of histamine and serum cytokine concentrations in mice fed diets containing different amounts of fat. Histamine reactivity was performed on mice back skin and serum cytokine concentrations were measured by ELISA in mice injected with anti-CD3 antibody. We measured serum interferon-gamma as a Th1-type cytokine and interleukin-4 as a Th2-type cytokine. Mice fed a high fat diet displayed enhanced skin reactivity of histamine and higher IL-4 levels in serum. These data suggest that a high fat diet may play a role in enhancing allergic reactions.

Analysis of leukocyte rolling and migration--using inhibitors in the undisturbed microcirculation of the rat mesentery--on inflammatory stimulation.

AIM: Our aim was to develop a method of migration analysis using the undisturbed microcirculation of rat mesentery, and using the new method, analyze leukocyte migration in casein-induced inflammation. METHOD: Sprague Dawley (SD) rats were injected with tumor necrosis factor (TNF) alpha, interleukin (IL)-1alpha, or casein intraperitoneally. Following this, the rats were sacrificed and the mesentery tissue removed was fixed and stained with Giemsa. The leukocytes were counted as a rolling index in the venules and as a migration index in the perivascular area. RESULTS: There was no relation between the diameter of venules and leukocyte migration. The time change curves of leukocyte activity in casein inflammation show about a 1 h difference between rolling and migration. From inhibitor experiments of casein-induced migration at 2 h, it has been suggested that selectin-related rolling is necessary. Platelet-activating factor (PAF) also appears partially involved. CONCLUSION: The improved undisturbed microcirculation method is helpful not only for rolling analysis but also in analysis of leukocyte migration. Casein inflammation analyzed using this method revealed that rolling is necessary and also suggested that partial involvement of PAF is necessary for pathogenesis of leukocyte extravasations.

Mac1 positive cells are required for enhancement of splenocytes proliferation caused by bisphenol a.

We examined the effects of bisphenol A (BPA) on immune cells and it was shown that BPA upregulated the proliferation of murine splenocytes stimulated with Concanavalin A (ConA). The upregulating effects of BPA were removed with depleting Mac1+ cells from the splenocytes. This study provides evidence for the first time that Mac1+ cells were required for enhancement of splenocytes proliferation caused by bisphenol A.

Inhibitory effects of several flavonoids on E-selectin expression on human umbilical vein endothelial cells stimulated by tumor necrosis factor-alpha.

The present study investigates the suppressive effect of flavonoids on TNF-alpha-stimulated E-selectin expression on HUVECs by carrying out a comparative examination of the 37 flavonoids. Several flavonoids: fisetin, luteolin and apigenin (subclass of flavone), kaempferol and quercetin (flavonols), eriodictyol (flavanones), genistein (isoflavones) and butein (chalcone) exhibit the inhibitory effects. Considerations to the structure of flavonoids, the C2-C3 double bond of C-ring and 4-oxo functional group are essential for their inhibition activities. These results help to explain the pharmacological efficacy of flavonoids as anti-inflammatory compounds.

Antigen feeding increases frequency and antigen-specific proliferation ability of intraepithelial CD4+ T cells in alphabeta T cell receptor transgenic mice.

To study how intestinal intraepithelial lymphocytes (IEL) are affected by orally ingested antigen, the phenotypes and responses of the IEL in mice expressing a transgenic T cell receptor alphabeta (TCR alphabeta) specific for ovalbumin (OVA) were analyzed after feeding OVA. In the OVA-fed mice, the abundance of alphabeta-IEL as a proportion of the total IEL population increased and the frequency of CD4+ cells increased within the TCR alphabeta+ IEL population. CD4(+) IEL from OVA-fed transgenic mice proliferated in vitro more markedly in response to antigen stimulation than IEL from mice fed the control diet. These results indicate that antigen-specific proliferation of CD4+ IEL was amplified as a result of oral administration of antigen.

CD4+CD25- T cells that express latency-associated peptide on the surface suppress CD4+CD45RBhigh-induced colitis by a TGF-beta-dependent mechanism.

Murine CD4(+)CD25(+) regulatory cells have been reported to express latency-associated peptide (LAP) and TGF-beta on the surface after activation, and exert regulatory function by the membrane-bound TGF-beta in vitro. We have now found that a small population of CD4(+) T cells, both CD25(+) and CD25(-), can be stained with a goat anti-LAP polyclonal Ab without being stimulated. Virtually all these LAP(+) cells are also positive for thrombospondin, which has the ability to convert latent TGF-beta to the active form. In the CD4(+)CD45RB(high)-induced colitis model of SCID mice, regulatory activity was exhibited not only by CD25(+)LAP(+) and CD25(+)LAP(-) cells, but also by CD25(-)LAP(+) cells. CD4(+)CD25(-)LAP(+) T cells were part of the CD45RB(low) cell fraction. CD4(+)CD25(-)LAP(-)CD45RB(low) cells had minimal, if any, regulatory activity in the colitis model. The regulatory function of CD25(-)LAP(+) cells was abrogated in vivo by anti-TGF-beta mAb. These results identify a new TGF-beta-dependent regulatory CD4(+) T cell phenotype that is CD25(-) and LAP(+).

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.

An improved method for measuring vascular permeability in rat and mouse skin.

INTRODUCTION: We have improved a rodent vascular permeability measurement method employing fluorescent dye-labeled bovine serum albumin. METHODS: The incubation duration for direct fluorescent detection of skin injected with an inflammatory agent was decided based on regression curve parameters with the correlation coefficient obtained from the least squares method. RESULTS: A suitable incubation time was determined to be 2-6 h. The recovery of FITC-BSA from the skin sample was very good, and the correlation coefficient of the linear regression curve was .99. The linear relation between the previous dye extraction method using brilliant blue 6B and the new and improved fluorescence method was very high. In mice, histamine-induced serum exudation in the back skin increased from 0.31 to 1.25 microg/site in a dose-dependent manner and reached a plateau at 1.25-2.5 microg/site. The serum exudation caused by histamine increased to 10 microg/site and almost reached a plateau at 10-40 microg/site in rats. The time required for the measurement of fluorescence intensity was very short because a microplate reader was used as the measurement apparatus. CONCLUSION: The improved method is easy to use and sensitive and does not necessitate extraction of dye from the skin.