Evaluating the Effects of Chronic Oral Exposure to the Food Additive Silicon Dioxide on Oral Tolerance Induction and Food Sensitivities in Mice.

BACKGROUND: The increasing prevalence of food sensitivities has been attributed to changes in gut microenvironment; however, ubiquitous environmental triggers such as inorganic nanoparticles (NPs) used as food additives have not been thoroughly investigated. OBJECTIVES: We explored the impact of the NP-structured food-grade silicon dioxide (fg-SiO2) on intestinal immune response involved in oral tolerance (OT) induction and evaluated the consequences of oral chronic exposure to this food-additive using a mouse model of OT to ovalbumin (OVA) and on gluten immunopathology in mice expressing the celiac disease risk gene, HLA-DQ8. METHODS: Viability, proliferation, and cytokine production of mesenteric lymph node (MLN) cells were evaluated after exposure to fg-SiO2. C57BL/6J mice and a mouse model of OT to OVA were orally exposed to fg-SiO2 or vehicle for 60 d. Fecal lipocalin-2 (Lcn-2), anti-OVA IgG, cytokine production, and immune cell populations were analyzed. Nonobese diabetic (NOD) mice expressing HLA-DQ8 (NOD/DQ8), exposed to fg-SiO2 or vehicle, were immunized with gluten and immunopathology was investigated. RESULTS: MLN cells exposed to fg-SiO2 presented less proliferative T cells and lower secretion of interleukin 10 (IL-10) and transforming growth factor beta (TGF-ß) by T regulatory and CD45+ CD11b+ CD103+ cells compared to control, two factors mediating OT. Mice given fg-SiO2 exhibited intestinal Lcn-2 level and interferon gamma (IFN-γ) secretion, showing inflammation and less production of IL-10 and TGF-ß. These effects were also observed in OVA-tolerized mice exposed to fg-SiO2, in addition to a breakdown of OT and a lower intestinal frequency of T cells. In NOD/DQ8 mice immunized with gluten, the villus-to-crypt ratio was decreased while the CD3+ intraepithelial lymphocyte counts and the Th1 inflammatory response were aggravated after fg-SiO2 treatment. DISCUSSION: Our results suggest that chronic oral exposure to fg-SiO2 blocked oral tolerance induction to OVA, and worsened gluten-induced immunopathology in NOD/DQ8 mice. The results should prompt investigation on the link between SiO2 exposure and food sensitivities in humans. https://doi.org/10.1289/EHP12758.

Vascular dysfunction and arterial hypertension in experimental celiac disease are mediated by gut-derived inflammation and oxidative stress.

AIMS: We examined the cardiovascular effects of celiac disease (CeD) in a humanized mouse model, with a focus on vascular inflammation, endothelial dysfunction, and oxidative stress. METHODS AND RESULTS: NOD.DQ8 mice genetically predisposed to CeD were subjected to a diet regime and oral gavage to induce the disease (gluten group vs. control). We tested vascular function, confirmed disease indicators, and evaluated inflammation and oxidative stress in various tissues. Plasma proteome profiling was also performed. CeD markers were confirmed in the gluten group, indicating increased blood pressure and impaired vascular relaxation. Pro-inflammatory genes were upregulated in this group, with increased CD11b+ myeloid cell infiltration and oxidative stress parameters observed in aortic and heart tissue. However, heart function remained unaffected. Plasma proteomics suggested the cytokine interleukin-17A (IL-17A) as a link between gut and vascular inflammation. Cardiovascular complications were reversed by adopting a gluten-free diet. CONCLUSION: Our study sheds light in the heightened cardiovascular risk associated with active CeD, revealing a gut-to-cardiovascular inflammatory axis potentially mediated by immune cell infiltration and IL-17A. These findings augment our understanding of the link between CeD and cardiovascular disease providing clinically relevant insight into the underlying mechanism. Furthermore, our discovery that cardiovascular complications can be reversed by a gluten-free diet underscores a critical role for dietary interventions in mitigating cardiovascular risks associated with CeD.

Investigating the response mechanisms of bread wheat mutants to salt stress.

Mutation breeding is among the most critical approaches to promoting genetic diversity when genetic diversity is narrowed for a long time using traditional breeding methods. In the current study, 15 wheat mutants created by gamma radiation and three salt-tolerant wheat cultivars were studied under no salinity stress (Karaj) and salinity stress (Yazd) during three consecutive growing seasons from 2017 to 2020 (M05 to M07 generations mutants). Results showed that salinity induced lipid peroxidation and enhanced ion leakage in all genotypes however, M6 and M15 showed the least ion leakage increment. It was also observed that the activity of antioxidant enzymes including SOD, CAT, POX, APX and GR increased with salinity; the maximum increase in antioxidant activity was belonged to M15, M09, M06 and M05. All genotypes had higher protein content in salinity stress conditions; M07 and M12 showed the lowest (1.8%) and the highest (17.3%) protein increase, respectively. Zeleny sedimentation volume increased under salinity stress conditions in all genotypes except M06, C2, C3, and M07. The result indicated that salinity stress increased wet gluten in all genotypes. M10 and M08 showed the highest (47.8%) and the lowest (4%) wet gluten increment, respectively. M06 and M11 mutants showed the lowest (6.1%) and the highest (60.7%) decrement of grain yield due to salinity stress, respectively. Finally, M04, M05, M07, M13, and M14 were known as genotypes with high grain yield in both no salinity and salinity stress conditions. In other word, these genotypes have higher yield stability. The results of the current study revealed that gamma irradiation could effectively be used to induce salinity tolerance in wheat.

Nitrogen enhances the effect of pre-drought priming against post-anthesis drought stress by regulating starch and protein formation in wheat.

Drought stress is one of the most serious environmental stress factor constraining crop production across the globe. Among cereals, wheat grains are very sensitive to drought as a small degree of stress can affect the enzymatic system. This study aimed to investigate whether nitrogen and pre-anthesis drought priming could enhance the action of major regulatory enzymes involved in starch accumulation and protein synthesis in bread wheat (Triticum aestivum L.). For this purpose, cultivars YM-158 (medium gluten) and YM-22 (low gluten) were grown in rain-controlled conditions under two nitrogen levels, that is, N180 (N1) and N300 (N2). Drought priming was applied at the jointing stage and drought stress was applied 7 days after anthesis. Drought stress reduced starch content but enhanced protein content in grains. N2 and primed plants kept higher contents of nonstructural carbohydrates, fructans, and sucrose; with higher activity of sucrose-phosphate synthase in flag leaves. Furthermore, N2 and priming treatments showed higher sink ability to develop grains by showing higher sucrose-to-starch conversion activities of adenosine diphosphate-glucose pyrophosphorylase, uridine diphosphate glucose pyrophosphorylase, sucrose-synthase, soluble-starch synthase, starch branching enzyme, and granule-bound starch synthase as compared to N1 and non-primed treatments. The application of N2 and primed treatment showed a greater ability to maintain grain filling in both cultivars as compared to N1 and non-primed crops. Our study suggested that high nitrogen has the potential to enhance the effect of pre-drought priming to change source-sink relationships and grain yield of wheat under drought stress during the filling process.

Effect of Protein Fermentation Products on Gut Health Assessed in an In Vitro Model of Human Colon (TIM-2).

SCOPE: Western type of diets are characterized by high animal protein intake and are associated with various chronic inflammatory diseases. With a higher protein consumption, excess undigested protein will reach the colon and be subsequently metabolized by gut microbiota. Depending on the type of protein, fermentation in the colon generates different metabolites with varying biological effects. This study aims to compare the impact of protein fermentation products from different sources on gut health. METHODS AND RESULTS: Three high protein diets (vital wheat gluten [VWG], lentil, or casein) are submitted to the in vitro model of colon. Fermentation of excess lentil protein for 72 h results in highest production of short-chain fatty acids and lowest production of branched-chain fatty acids. Exposure of Caco-2 monolayers or Caco-2 monolayers co-cultured with THP-1 macrophages to luminal extracts of fermented lentil protein results in less cytotoxicity of Caco-2 monolayers and less damage to barrier integrity, when compared to VWG and casein. Lowest induction of interleukin-6 is observed in THP-1 macrophages after treatment with lentil luminal extracts, which is identified to be regulated by aryl hydrocarbon receptor signaling. CONCLUSION: The findings indicate that protein sources affect the health effects of high protein diet in the gut.

A Case Study of the Response of Immunogenic Gluten Peptides to Sourdough Proteolysis.

Celiac disease is activated by digestion-resistant gluten peptides that contain immunogenic epitopes. Sourdough fermentation is a potential strategy to reduce the concentration of these peptides within food. However, we currently know little about the effect of partial sourdough fermentation on immunogenic gluten. This study examined the effect of a single sourdough culture (representative of those that the public may consume) on the digestion of immunogenic gluten peptides. Sourdough bread was digested via the INFOGEST protocol. Throughout digestion, quantitative and discovery mass spectrometry were used to model the kinetic release profile of key immunogenic peptides and profile novel peptides, while ELISA probed the gluten's allergenicity. Macrostructural studies were also undertaken. Sourdough fermentation altered the protein structure, in vitro digestibility, and immunogenic peptide release profile. Interestingly, sourdough fermentation did not decrease the total immunogenic peptide concentration but altered the in vitro digestion profile of select immunogenic peptides. This work demonstrates that partial sourdough fermentation can alter immunogenic gluten digestion, and is the first study to examine the in vitro kinetic profile of immunogenic gluten peptides from sourdough bread.

Dietary protein source contributes to the risk of developing maternal syndrome in the Dahl salt-sensitive rat.

Preeclampsia (PE) is a disorder of pregnancy, which is categorized by hypertension and proteinuria or signs of end-organ damage. Though PE is the leading cause of maternal and fetal morbidity and mortality, the mechanisms leading to PE remain unclear. The present study examined the contribution of dietary protein source (casein versus wheat gluten) to the risk of developing maternal syndrome utilizing two colonies of Dahl salt-sensitive (SS/JrHsdMcwi) rats. While the only difference between the colonies is the diet, the colonies exhibit profound differences in the pregnancy phenotypes. The SS rats maintained on the wheat gluten (SSWG) chow are protected from developing maternal syndrome; however, approximately half of the SS rats fed a casein-based diet (SSC) exhibit maternal syndrome. Those SSC rats that develop pregnancy-specific increases in blood pressure and proteinuria have no observable differences in renal or placental immune profiles compared to the protected SS rats. A gene profile array of placental tissue revealed a downregulation in Nos3 and Cyp26a1 in the SSC rats that develop maternal syndrome accompanied with increases in uterine artery resistance index suggesting the source of this phenotype could be linked to inadequate remodeling within the placenta. Investigations into the effects of multiple pregnancies on maternal health replicated similar findings. The SSC colony displayed an exacerbation in proteinuria, renal hypertrophy and renal immune cell infiltration associated with an increased mortality rate while the SSWG colony were protected highlighting how dietary protein source could have beneficial effects in PE.

The effect of gluten on skin and hair: a systematic review.

Non-celiac gluten sensitivity is often clinically indistinguishable from celiac disease, and patients show improvement or resolution of their symptoms with a gluten-free diet. In contrast to celiac disease, the effects of gluten on the skin and hair in the context of non-celiac gluten sensitivity are not as clear. This review aims to describe the impact of gluten on the skin and hair in patients with non-celiac gluten sensitivity and those without a definitive celiac disease diagnosis. A literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) reporting guidelines for systematic reviews. Forty-two publications met inclusion criteria with five studies describing the skin manifestations of non-celiac gluten sensitivity. Trials identifying the impact of a gluten-free diet on skin disease, as well as dermatologic conditions and their associations with antigliadin antibodies were also identified. Dermatologic manifestations in patients with non-celiac gluten sensitivity vary and may be non-specific. It may be appropriate for some of these patients with skin manifestations to trial a gluten-free diet. Dermatologic conditions that may respond positively to a gluten-free diet include psoriasis, atopic dermatitis, vitiligo, and palmoplantar pustulosis, while linear IgA disease does not appear to improve with this dietary change.

Antioxidant properties and inhibition of angiotensin-converting enzyme by highly active peptides from wheat gluten.

This study aimed to focus on the high-value utilization of raw wheat gluten by determining the potent antioxidant peptides and angiotensin I-converting enzyme (ACE) inhibitory peptides from wheat gluten oligopeptides (WOP). WOP were analyzed for in vitro antioxidant activity and inhibition of ACE, and the identification of active peptides was performed by reversed-phase high-performance liquid chromatography and mass spectrometry. Quantitative analysis was performed for highly active peptides. Five potent antioxidant peptides, Leu-Tyr, Pro-Tyr, Tyr-Gln, Ala-Pro-Ser-Tyr and Arg-Gly-Gly-Tyr (6.07 ± 0.38, 7.28 ± 0.29, 11.18 ± 1.02, 5.93 ± 0.20 and 9.04 ± 0.47 mmol 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) equivalent/g sample, respectively), and five potent ACE inhibitory peptides, Leu-Tyr, Leu-Val-Ser, Tyr-Gln, Ala-Pro-Ser-Tyr and Arg-Gly-Gly-Tyr (half maximal inhibitory concentration (IC50) values = 0.31 ± 0.02, 0.60 ± 0.03, 2.00 ± 0.13, 1.47 ± 0.08 and 1.48 ± 0.11 mmol/L, respectively), were observed. The contents of Leu-Tyr, Pro-Tyr, Tyr-Gln, Ala-Pro-Ser-Tyr, Arg-Gly-Gly-Tyr, and Leu-Val-Ser were 155.04 ± 8.36, 2.08 ± 0.12, 1.95 ± 0.06, 22.70 ± 1.35, 0.25 ± 0.01, and 53.01 ± 2.73 µg/g, respectively, in the WOP. Pro-Tyr, Tyr-Gln, Ala-Pro-Ser-Tyr, Arg-Gly-Gly-Tyr, and Leu-Val-Ser are novel antioxidative/ACE inhibitory peptides that have not been previously reported. The results suggest that WOP could potentially be applied in the food industry as a functional additive.

Protein Digests and Pure Peptides from Chia Seed Prevented Adipogenesis and Inflammation by Inhibiting PPARγ and NF-κB Pathways in 3T3L-1 Adipocytes.

The objective was to evaluate the mechanisms of digested total proteins (DTP), albumin, glutelin, and pure peptides from chia seed (Salvia hispanica L.) to prevent adipogenesis and its associated inflammation in 3T3-L1 adipocytes. Preadipocytes (3T3-L1) were treated during differentiation with either DTP or digested albumin or glutelin (1 mg/mL) or pure peptides NSPGPHDVALDQ and RMVLPEYELLYE (100 µM). Differentiated adipocytes also received DTP, digested albumin or glutelin (1 mg/mL), before (prevention) or after (inhibition) induced inflammation by addition of conditioned medium (CM) from inflamed macrophages. All treatments prevented adipogenesis, reducing more than 50% the expression of PPARγ and to a lesser extent lipoprotein lipase (LPL), fatty acid synthase (FAS), sterol regulatory element-binding protein 1 (SREBP1), lipase activity and triglycerides. Inflammation induced by CM was reduced mainly during prevention, while DTP decreased expression of NF-κB (-48.4%), inducible nitric oxide synthase (iNOS) (-46.2%) and COX-2 (-64.5%), p < 0.05. Secretions of nitric oxide, PGE2 and TNFα were reduced by all treatments, p < 0.05. DTP reduced expressions of iNOS (-52.1%) and COX-2 (-66.4%). Furthermore, digested samples and pure peptides prevented adipogenesis by modulating PPARγ and additionally, preventing and even inhibiting inflammation in adipocytes by inhibition of PPARγ and NF-κB expression. These results highlight the effectiveness of digested total proteins and peptides from chia seed against adipogenesis complications in vitro.

Investigation of the Effects of Glutens on Serum Interleukin-1 Beta and Tumor Necrosis Factor-Alpha Levels and the Immunohistochemical Distribution of CD3 and CD8 Receptors in the Small Intestine in Male Rats

Abstract While the role of cytokines in celiac disease has been investigated in detail, cytokine release in the event of the exposure of healthy subjects to glutens has only recently been studied. This study was aimed at determining the effects of corn and wheat glutens, incorporated as protein sources into the diet, on serum interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels and the immunohistochemical distribution of CD3 and CD8 receptors in the small intestine in male rats. The study material comprised 24 twenty-day-old male Wistar albino rats, which were randomly assigned in equal numbers to three groups (2 rats/replicate and 4 replicates/group). The feed rations provided to all three groups contained high levels of proteins, which were soybean meal, corn gluten and wheat gluten in the control, corn and wheat groups, respectively. The in Control, Corn and Wheat groups serum IL-1 beta and TNF-alpha levels respectively 55.83 - 46.37; 81.65 - 61.95 and 81.65-61.31 was determined but these differences were statistically insignificant. Furthermore, immunohistochemical examination demonstrated a mathematical increase to have occurred in the distribution of the CD3 and CD8 receptors in the duodenum, jejunum and ileum samples of the corn and wheat groups. In result, based on the findings obtained in this study, we suggest that the long-term feeding of rats on high levels of gluten causes systemic adverse effects.

Pro-Inflammatory Effect of Gliadins and Glutenins Extracted from Different Wheat Cultivars on an In Vitro 3D Intestinal Epithelium Model.

There is a need to assess the relationship between improved rheological properties and the immunogenic potential of wheat proteins. The present study aimed to investigate the in vitro effects of total protein extracts from three modern and two landrace Triticum aestivum commercial flour mixes, with significant differences in gluten strength (GS), on cell lines. Cytotoxicity and innate immune responses induced by wheat proteins were investigated using Caco-2 monocultures, two dimensional (2D) Caco-2/U937 co-cultures, and three dimensional (3D) co-cultures simulating the intestinal mucosa with Caco-2 epithelial cells situated above an extra-cellular matrix containing U937 monocytes and L929 fibroblasts. Modern wheat proteins, with increased GS, significantly reduced Caco-2 cell proliferation and vitality in monoculture and 2D co-cultures than landrace proteins. Modern wheat proteins also augmented Caco-2 monolayer disruption and tight junction protein, occludin, redistribution in 3D co-cultures. Release of interleukin-8 into the cell medium and increased U937 monocyte migration in both 2D and 3D co-cultures were similarly apparent. Immuno-activation of migrating U937 cells was evidenced from cluster of differentiation 14 (CD14) staining and CD11b-related differentiation into macrophages. The modern wheat proteins, with gluten polymorphism relatedness and increased GS, were shown to be more cytotoxic and immunogenic than the landrace wheat proteins.

Dietary Gluten as a Conditioning Factor of the Gut Microbiota in Celiac Disease.

The gut microbiota plays a relevant role in determining an individual's health status, and the diet is a major factor in modulating the composition and function of gut microbiota. Gluten constitutes an essential dietary component in Western societies and is the environmental trigger of celiac disease. The presence/absence of gluten in the diet can change the diversity and proportions of the microbial communities constituting the gut microbiota. There is an intimate relation between gluten metabolism and celiac disease pathophysiology and gut microbiota; their interrelation defines intestinal health and homeostasis. Environmental factors modify the intestinal microbiota and, in turn, its changes modulate the mucosal and immune responses. Current evidence from studies of young and adult patients with celiac disease increasingly supports that dysbiosis (i.e., compositional and functional alterations of the gut microbiome) is present in celiac disease, but to what extent this is a cause or consequence of the disease and whether the different intestinal diseases (celiac disease, ulcerative colitis, Crohn disease) have specific change patterns is not yet clear. The use of bacterial-origin enzymes that help completion of gluten digestion is of interest because of the potential application as coadjuvant in the current treatment of celiac disease. In this narrative review, we address the current knowledge on the complex interaction between gluten digestion and metabolism, celiac disease, and the intestinal microbiota.

Masked bolus gluten challenge low in FODMAPs implicates nausea and vomiting as key symptoms associated with immune activation in treated coeliac disease.

BACKGROUND: In patients with coeliac disease, FODMAPs in gluten-containing foods, and participant anticipation of a harmful ('nocebo') effect, may contribute to acute symptoms after gluten challenge. AIM: To establish acute gluten-specific symptoms linked to immune activation in coeliac disease METHODS: We included 36 coeliac disease patients on a gluten-free diet receiving placebo in the RESET CeD trial. Double-blind, bolus vital wheat gluten (~6-g gluten protein) and sham challenges low in FODMAPs were consumed 2 weeks apart. Assessments included daily Coeliac Disease Patient Reported Outcome (CeD PRO) symptom scores (0-10), adverse events and serum interleukin-2 (baseline and 4 hours). RESULTS: Median CeD PRO score for nausea increased most (sham: 0 vs gluten: 5.5; P < .001). Apart from tiredness (1 vs 4, P = .005) and headache (0 vs 2, P = .002), changes in other symptoms were small or absent. Only nausea increased significantly in occurrence with gluten (11% vs 69%, P < .001). Without nausea, only tiredness and flatulence were common after gluten. Nausea (6% vs 61%, P < .001; median onset: 1:34 hours) and vomiting (0% vs 44%, P < .001; 1:51 hours) were the only adverse events more common with gluten than sham. Interleukin-2 was always below the level of quantitation (0.5 pg/mL) at baseline, and after sham. Interleukin-2 was elevated after gluten in 97% of patients (median fold-change: 20), and correlated with severity of nausea (rs  = .49, P = .0025) and occurrence of vomiting (P = .0005). CONCLUSIONS: Nausea and vomiting are relatively specific indicators of acute gluten ingestion, and correlate with immune activation. IBS-like symptoms without nausea are unlikely to indicate recent gluten exposure.

The Janus Face of Cereals: Wheat-Derived Prebiotics Counteract the Detrimental Effect of Gluten on Metabolic Homeostasis in Mice Fed a High-Fat/High-Sucrose Diet.

SCOPE: Cereals are important sources of carbohydrates, but also contain nutrients that could impact adiposity. The contribution of gluten to obesity and the effects of prebiotics-arabinoxylo-oligosaccharides (AXOS) and fructo-oligosaccharides (FOS)-that can be extracted from gluten-containing cereals are analyzed. METHODS AND RESULTS: Mice are fed a control diet, Western diet (WD, consisting of high fat/high sucrose), or WD with 5% gluten. Prebiotics are tested in the WD with gluten. Gluten does not increase body weight and has a minor effect on ileal inflammation. Gluten decreases the expression of browning markers in the fat and increases the triglycerides synthesis in the muscle. AXOS decreases body weight and adiposity in fat pads muscle and liver. AXOS promotes gluten cleavage by the induction of prolyl endopeptidase that is translated into a reduction of gluten immunogenic peptides. Gluten has minor effects on cecal microbiota composition, whereas prebiotics increased Bifidobacterium, Butyricicoccus, Prevotella, and Parasutterella, which are all negatively correlated to the cecal content of gluten peptides. CONCLUSION: While gluten may affect metabolic homeostasis, these effects are lessened when gluten is consumed along with cereal-derived fibers. If confirmed in humans, the authors bring new arguments to eat fiber-rich cereals to promote a healthy diet.

Wheat Gluten Regulates Cholesterol Metabolism by Modulating Gut Microbiota in Hamsters with Hyperlipidemia.

The objective of this research was to evaluate the effect of wheat gluten on gut microbiota from hamsters and also analyse whether alterations in microbiota could result in wheat gluten's lipid-lowering properties. Four weeks male hamsters were divided into 3 groups (n=10). Two hypercholesterolemic groups were fed for 35 days with hypercholesterolemic diet, containing 20% (w/w) wheat gluten or casein. Wheat gluten significantly reduced serum total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) concentrations, and also decreased the liver total cholesterol (TC), free cholesterol (FC), cholesterol ester (CE), triglycerides (TG) concentrations. Wheat gluten group had a higher fecal lipids, total cholesterol (TC) and bile acids (BA) than that of casein group (p < 0.05). Moreover, wheat gluten significantly increased total short-chain fatty acids (SCFA) concentrations in feces. Sequencing of 16S rRNA gene revealed that intake of wheat gluten decreased the relative abundances of Firmicutes and Erysipelotrichaceae, but to increased the relative abundances of Bateroidetes, Bacteroidales_S24-7_group and Ruminococcaceae. The lipid lowering properties of wheat gluten was associated with the lower ratio of Firmicutes/Bateroidetes, the lower of the bacterial taxa Erysipelotrichaceae and the higher of the bacterial taxa Bacteroidales_S24-7_group and Ruminococcaceae. These results suggest that wheat gluten modulate cholesterol metabolism by altering intestinal microflora.

Chia (Salvia hispanica L.) Seed Total Protein and Protein Fractions Digests Reduce Biomarkers of Inflammation and Atherosclerosis in Macrophages In Vitro.

SCOPE: The objectives are to evaluate the anti-inflammatory and anti-atherosclerotic effects of digested total protein and digested protein fractions from chia seed in macrophages in vitro. METHODS AND RESULTS: Total protein and protein fractions (albumin, globulin, glutelin, and prolamin) are isolated from chia seed and digested using simulated gastrointestinal conditions, resulting in digested total protein (DTP) and digested protein fractions (DPF). DTP and DPF are applied (1.0 mg mL-1 ) in RAW 264.4 macrophages stimulated with LPS (1 µg mL-1 ) for inflammation or ox-LDL (80 µg mL-1 ) for atherosclerosis. In the inflammatory process, DTP and DPF reduce p-NF-κB, iNOS, p-JNK, and AP-1. Digested glutelin reduces the secretion of nitric oxide (65.1%), reactive oxygen species (19.7%), prostaglandins (34.6%), TNF-α (24.1%), MCP-1 (18.9%), IL-6 (39.6%), and IL-10 (68.7%). DTP and DPF reduce the NF-κB translocation to nuclei. DTP and digested glutelin reduce iCAM expression (86.4%, 80.8%), LOX-1 (37.3%, 35.7%), iNOS (67.0%, 42.2%), and NF-κB (57.5%, 71.1%). DTP is effective in reducing secretion of nitric oxide (43.4%), lipid accumulation (41.9%), prostaglandins (41.9%), TNF-α (43.3%), MCP-1 (47.6%), and IL-6 (50.5%). Peptides from chia DTP and DPF are also characterized. CONCLUSION: DTP and digested glutelin from chia seed reduce expression and secretion of markers related to inflammation and atherosclerosis pathways.

Human gut derived-organoids provide model to study gluten response and effects of microbiota-derived molecules in celiac disease.

Celiac disease (CD) is an immune-mediated disorder triggered by gluten exposure. The contribution of the adaptive immune response to CD pathogenesis has been extensively studied, but the absence of valid experimental models has hampered our understanding of the early steps leading to loss of gluten tolerance. Using intestinal organoids developed from duodenal biopsies from both non-celiac (NC) and celiac (CD) patients, we explored the contribution of gut epithelium to CD pathogenesis and the role of microbiota-derived molecules in modulating the epithelium's response to gluten. When compared to NC, RNA sequencing of CD organoids revealed significantly altered expression of genes associated with gut barrier, innate immune response, and stem cell functions. Monolayers derived from CD organoids exposed to gliadin showed increased intestinal permeability and enhanced secretion of pro-inflammatory cytokines compared to NC controls. Microbiota-derived bioproducts butyrate, lactate, and polysaccharide A improved barrier function and reduced gliadin-induced cytokine secretion. We concluded that: (1) patient-derived organoids faithfully express established and newly identified molecular signatures characteristic of CD. (2) microbiota-derived bioproducts can be used to modulate the epithelial response to gluten. Finally, we validated the use of patient-derived organoids monolayers as a novel tool for the study of CD.

Wheat gluten protein inhibits α-amylase activity more strongly than a soy protein isolate based on kinetic analysis.

The objective of this study was to investigate the porcine pancreatic α-amylase (PPA) inhibitory activity of botanical food proteins, represented by soy protein isolate (SPI) and wheat gluten protein (WGP). The half maximal inhibitory concentration (IC50) was determined, and the kinetics of inhibition were investigated using Dixon, Cornish-Bowden, and Lineweaver-Burk plots. The results showed WGP functioned as mixed-type inhibitors with both competitive and uncompetitive inhibitory characteristics, while SPI showed competitive inhibitory effects on α-amylase. The competitive inhibition constants (Kic) of WGP and SPI were 5.753 and 30.212 mg/mL, respectively, and the uncompetitive inhibition constants (Kiu) of WGP was 45.110 mg/mL, respectively. The IC50 values of WGP and SPI were 3.086 and 33.899 mg/mL, respectively. For WGP, the lower Kic vs. Kiu for mixed-type inhibitors suggested that they bound more tightly to free PPA than the PPA-starch complex. Compared with SPI, WGP displayed a stronger inhibitory effect on α-amylase. These results indicated that SPI and WGP may delay the digestion of starchy foods by inhibiting starch hydrolytic enzymes, which may be of relevance in vivo during gastrointestinal digestion. The findings are also of important practical value for the development of carbohydrate-restricted diet and protein-based functional foods.

Effects of tea polyphenols and gluten addition on in vitro wheat starch digestion properties.

Starch-containing food normally has complex components and structure, which control its digestion kinetic properties and nutritional value. However, interactions among multiple food components and their effects on starch digestion kinetics are rarely reported. Here, we evaluated the influence of tea polyphenols [i.e., (-)-epigallocatechin (EGC) and (-)­epigallocatechin­3­gallate (EGCG)] on the in vitro digestion rate and extent of wheat starch in the presence of gluten under uncooked and cooked conditions. The addition of EGC (20%, starch basis) did not change the starch digestion rate and extent for both uncooked and cooked physical forms in the presence and absence of gluten, whereas EGCG (20%, starch basis) significantly reduced the digestion extent of wheat starch by 25-30% in the absence of gluten and by 6.6-18.5% in the presence of gluten, a phenomenon that was caused by the reduced effective EGCG due to its interaction with gluten.