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.

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 (f g - SiO 2 ) 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 f g - SiO 2 . C57BL/6J mice and a mouse model of OT to OVA were orally exposed to f g - SiO 2 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 f g - SiO 2 or vehicle, were immunized with gluten and immunopathology was investigated.

RESULTS

MLN cells exposed to f g - SiO 2 presented less proliferative T cells and lower secretion of interleukin 10 (IL-10) and transforming growth factor beta (TGF- β ) by T regulatory and CD 45 + CD 11 b + CD 103 + cells compared to control, two factors mediating OT. Mice given f g - SiO 2 exhibited intestinal Lcn-2 level and interferon gamma (IFN- γ ) secretion, showing inflammation and less production of IL-10 and TGF- β . These effects were also observed in OVA-tolerized mice exposed to f g - SiO 2 , 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 CD 3 + intraepithelial lymphocyte counts and the Th1 inflammatory response were aggravated after f g - SiO 2 treatment.

DISCUSSION

Our results suggest that chronic oral exposure to f g - SiO 2 blocked oral tolerance induction to OVA, and worsened gluten-induced immunopathology in NOD/DQ8 mice. The results should prompt investigation on the link between SiO 2 exposure and food sensitivities in humans. https://doi.org/10.1289/EHP12758.

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.

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.

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.

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.

The Effect of Gluten-Free Diet on Health and the Gut Microbiota Cannot Be Extrapolated from One Population to Others

Gluten-related disorders (GRD) affect millions of people worldwide and have been related to the composition and metabolism of the gut microbiota. These disorders present differently in each patient and the only treatment available is a strict life-long gluten-free diet (GFD). Several studies have investigated the effect of a GFD on the gut microbiota of patients afflicted with GRD as well as healthy people. The purpose of this review is to persuade the biomedical community to think that, while useful, the results from the effect of GFD on health and the gut microbiota cannot be extrapolated from one population to others. This argument is primarily based on the highly individualized pattern of gut microbial composition and metabolic activity in each person, the variability of the gut microbiota over time and the plethora of factors associated with this variation. In addition, there is wide variation in the composition, economic viability, and possible deleterious effects to health among different GFD, both within and among countries. Overall, this paper encourages the conception of more collaborative efforts to study local populations in an effort to reach biologically and medically useful conclusions that truly contribute to improve health in patients afflicted with GRD.

Thermo-reversible inhibition makes aqualysin 1 from Thermus aquaticus a potent tool for studying the contribution of the wheat gluten network to the crumb texture of fresh bread

The thermo-active serine peptidase aqualysin 1 (Aq1) of Thermus aquaticus was applied in bread making to study the relative contribution of thermoset gluten to bread crumb texture. Aq1 is active between 30 °C and 90 °C with an optimum activity temperature of around 65 °C. It is inhibited by wheat endogenous serine peptidase inhibitors during dough mixing and fermentation and starts hydrolyzing gluten proteins during baking above 80 °C when the enzyme is no longer inhibited and most of the starch is gelatinized and contributes to structure formation. Aq1 activity reduced the molecular weight of gluten proteins and significantly increased their extractability in sodium dodecyl sulfate containing medium. While it had no impact on the specific bread volume and only limited impact on hardness, cohesiveness, springiness, resilience and chewiness, it impacted bread crumb coherence. We conclude that starch has a greater impact on crumb texture than thermoset gluten.

The Effect of Vegan Protein-Based Diets on Metabolic Parameters, Expressions of Adiponectin and Its Receptors in Wistar Rats

Vegan protein-based diet has attracted increasing interest in the prevention of metabolic syndrome (MetS). Meanwhile, adiponectin has become a highly potential molecular target in the prevention of MetS. Our study will identify a potential vegan protein diet for the prevention of MetS using rat models. Thirty-six Wistar rats were randomly assigned into three groups and given diets containing one of the following proteins for 12 weeks: casein (CAS, control diet), soy protein (SOY), and gluten-soy mixed protein (GSM). Changes in metabolic parameters as well as the expressions of adiponectin and its receptors were identified. Compared to CAS diet, both SOY and GSM diets led to decreases in blood total cholesterol and triglycerides, but only GSM diet led to an increase in HDL-cholesterol; no marked difference was observed in blood glucose in all three groups; HOMA-IR was found lower only in SOY group. Among groups, the order of serum adiponectin level was found as GSM > SOY > CAS. Similar order pattern was also observed in expression of adiponectin in adipose tissue and AdipoR1 mRNA in skeletal muscle. Our results suggested for the first time that, besides SOY diet, GSM diet could also be a possible substitute of animal protein to prevent MetS.

Corn Gluten Hydrolysate Affects the Time-Course of Metabolic Changes Through Appetite Control in High-Fat Diet-Induced Obese Rats

This study first investigated the effects of corn gluten hydrolysate (CGH) (1.5 g/day) administration for 7 days on appetite-responsive genes in lean Sprague-Dawley (SD) rats. In a second set of experiments, the metabolic changes occurring at multiple time points over 8 weeks in response to CGH (35.33% wt/wt) were observed in high-fat (HF, 60% of energy as fat) diet-fed SD rats. In lean rats, the hypothalamus neuropeptide-Y and proopiomelanocortin mRNA levels of the CGH group were significantly changed in response to CGH administration. In the second part of the study, CGH treatment was found to reduce body weight and perirenal and epididymal fat weight. CGH also prevented an increase in food intake at 2 weeks and lowered plasma leptin and insulin levels in comparison with the HF group. This reduction in the plasma and hepatic lipid levels was followed by improved insulin resistance, and the beneficial metabolic effects of CGH were also partly related to increases in plasma adiponectin levels. The Homeostasis Model of Assessment - Insulin Resistance (HOMA-IR), an index of insulin resistance, was markedly improved in the HF-CGH group compared with the HF group at 6 weeks. According to the microarray results, adipose tissue mRNA expression related to G-protein coupled receptor protein signaling pathway and sensory perception was significantly improved after 8 weeks of CGH administration. In conclusion, the present findings suggest that dietary CGH may be effective for improving hyperglycemia, dyslipidemia and insulin resistance in diet-induced obese rats as well as appetite control in lean rats.

The Effect of Plant Proteins Derived from Cereals and Legumes on Heme Iron Absorption

The aim of this study is to determine the effect of proteins from cereals and legumes on heme iron (Fe) absorption. The absorption of heme Fe without its native globin was measured. Thirty adult females participated in two experimental studies (15 per study). Study I focused on the effects of cereal proteins (zein, gliadin and glutelin) and study II on the effects of legume proteins (soy, pea and lentil) on heme Fe absorption. When heme was given alone (as a control), study I and II yielded 6.2% and 11.0% heme absorption (p > 0.05). In study I, heme Fe absorption was 7.2%, 7.5% and 5.9% when zein, gliadin and glutelin were added, respectively. From this, it was concluded that cereal proteins did not affect heme Fe absorption. In study II, heme Fe absorption was 7.3%, 8.1% and 9.1% with the addition of soy, pea and lentil proteins, respectively. Only soy proteins decreased heme Fe absorption (p < 0.05). These results suggest that with the exception of soy proteins, which decreased absorption, proteins derived from cereals and legumes do not affect heme Fe absorption.

Effects of flaxseed encapsulation on biohydrogenation of polyunsaturated fatty acids by ruminal microorganisms: feedlot performance, carcass quality, and tissue fatty acid composition

The objective of this study was to evaluate the efficacy of protecting PUFA within ground flaxseed against ruminal biohydrogenation by encapsulating them in a matrix consisting of a 1:1 blend of ground flaxseed and dolomitic lime hydrate (L-Flaxseed). Crossbreed heifers ( = 462, 346 ± 19 kg) were blocked by weight and randomly assigned to pens. Pens were assigned to 1 of 6 dietary treatments in a randomized complete block design. Treatment 1 consisted of a combination of 54.6% steam-flaked corn (SFC), 30.0% wet corn gluten feed, 8.0% roughage, and supplement (0% flaxseed). In treatments 2 and 3, a proportion of SFC was replaced with 3 and 6% flaxseed, respectively; in treatments 4, 5, and 6, SFC was replaced with 2, 4, or 6% L-Flaxseed, respectively. Cattle were fed for 140 or 168 d and then harvested in a commercial abattoir where carcass data were collected. Approximately 24 h after harvest, carcasses were evaluated for 12th-rib fat thickness, KPH, LM area, marbling score, and USDA yield and quality grades. Samples of LM were also obtained for determination of long-chain fatty acid profiles. Cattle that were fed diets with 4 and 6% L-Flaxseed consumed less feed than other treatments ( < 0.05), which adversely affected ADG. Compared with cattle fed 0% flaxseed, cattle in these treatments had lower final BW (18 and 45 kg less for the 4 and 6% L-Flaxseed treatments, respectively), less ADG (0.16 and 0.48 kg/day less for the 4 and 6% L-Flaxseed treatments, respectively), and lower carcass weights, dressing percentages, LM areas, backfat thicknesses, and marbling scores ( < 0.05). The addition of flaxseed or 2% L-Flaxseed did not affect performance or carcass traits ( > 0.05). Supplementation with flaxseed increased ( < 0.05) the concentration of α-linolenic acid (ALA) in meat (0.173, 0.482, 0.743 mg/g for 0, 3, and 6% flaxseed, respectively). Furthermore, proportionate increases in the ALA content of muscle tissue were 47% greater when flaxseed was encapsulated within the dolomitic lime hydrate matrix (0.288, 0.433, 0.592 mg/g for 2, 4, and 6% L-Flaxseed, respectively). Both products showed a linear response in ALA concentration ( > 99%; increases for Flaxseed and L-Flaxseed of 0.095 and 0.140 mg of ALA/g of tissue for each percentage of flaxseed added). This study indicates that a matrix consisting of dolomitic lime hydrate is an effective barrier to ruminal biohydrogenation of PUFA; however, adverse effects on DMI limit the amounts that can be fed.

Effects of Rice Proteins from Two Cultivars,KoshihikariandShunyo, on Cholesterol and Triglyceride Metabolism in Growing and Adult Rats

The effect and mechanism of two types of rice protein, one from regular japonica rice Koshihikari and another from rice cultivar Shunyo, with low glutelin and high prolamin content, on cholesterol and triglyceride metabolism were compared by feeding casein and soy protein to male Wistar strain rats 7 and 20 weeks old ad libitum for 2 weeks. The results in adult rats clearly indicated that both rice proteins had cholesterol-lowering effects in the plasma and the liver, comparable to soy protein, and the effects were accompanied with TG-lowering effects in the liver. Similar effects were also observed in growing rats when the diets were supplemented with cholesterol. The mechanism of the cholesterol-lowering effects by these rice proteins cannot be explained solely by fecal steroid excretion, but the results indicate that not only regular rice protein but also Shunyo rice protein possesses improving effects on lipid metabolism, especially in the adult period.

Effect of Wheat Gluten Hydrolysate on the Immune System in Healthy Human Subjects

Nine healthy volunteers were divided into a test group (n = 5) and a control group (n = 4). The test group consumed 3 grams per d of wheat gluten hydrolysate for 6 d, and their NK cell activity and hematological parameters were measured: The same assessments were performed in the control group, which did not receive wheat gluten hydrolysate. In the test group, NK cell activity increased significantly (P = 0.018) after wheat gluten hydrolysate intake. No adverse effects were observed in either group.

Comparison of the Effects of Di(2-ethylhexyl)phthalate, a Peroxisome Proliferator, on the Vitamin Metabolism Involved in the Energy Formation in Rats Fed with a Casein or Gluten Diet

In order to find an alleviation method for the adverse effect of environmental endocrine disrupters, we studied the effects of the putative endocrine disrupter and peroxisome proliferator, di(2-ethylhexyl)phthalate (DEHP), on animal growth and vitamin metabolism. It is known that the effects of chemical compounds such as xenobiotics differ according to the dietary protein source. We compared the effects of dietary DEHP administration on rats fed with a diet containing milk casein or wheat gluten. The increased conversion ratio of tryptophan to nicotinamide by DEHP administration was significantly higher in the casein group than in the gluten group. We also investigated the effects of DEHP on the urinary excretion of other vitamins. DEHP administration resulted in decreased urinary excretion of vitamin B(1), vitamin B(2), and pantothenic acid.

Are 'leaky gut' and behavior associated with gluten and dairy containing diet in children with autism spectrum disorders?

OBJECTIVES

Studies have suggested a link between diet and behavior in children with autism spectrum disorders (ASDs). Parental reports of behavioral changes upon exposure to gluten and/or casein are common in clinical practice. An association between diet type, intestinal permeability (IP) ('leaky gut'), and behavior has been long proposed but not substantiated. We explored this possible association in this trial.

METHODS

This randomized double-blind, placebo-controlled study explored the effects of gluten and milk on IP and behavior in children with ASDs over a period of 4 weeks. IP assessed by lactulose:mannitol (L/M) sugar permeability test and behavior assessed by the Aberrant Behavior Checklist and Conners Parent Rating were measured. Gastrointestinal symptoms in both groups were also monitored.

RESULTS

Neither the L/M ratio nor behavioral scores were different between groups exposed to gluten/dairy or placebo. The changes observed were noted to be small and not clinically significant.

DISCUSSION

Our study although underpowered to show small differences does not support an association between dietary gluten/milk, IP, and behavioral changes in subjects with ASD.

Beneficial effects of wheat gluten hydrolysate to extend lifespan and induce stress resistance in nematode Caenorhabditis elegans

Previous studies have showed that wheat gluten hydrolysate (WGH) has the anti-oxidative property. In the present study, we examined the possible safety property of WGH and the beneficial effects of WGH to extend lifespan and induce stress resistance using nematode Caenorhabditis elegans as the in vivo assay system. We found that WGH at concentrations of 0.1–1 mg/mL did not cause lethality, influence development, alter locomotion behavior and brood size, and induce significant intestinal autofluorescence and reactive oxygen species (ROS) production in young adults. Treatment with 0.1–1 mg/mL of WGH significantly extended lifespans of nematodes under the normal conditions. Moreover, WGH treatment significantly inhibited the induction of intestinal autofluorescence and suppressed the decrease in locomotion behavior during the aging process of nematodes. Furthermore, pre-treatment with 1 mg/mL of WGH significantly suppressed the adverse effects caused by heat-stress or oxidative stress on nematodes as indicated by the alterations of both lifespan and intestinal ROS production. Therefore, WGH treatment is relatively safe and has beneficial effects on nematodes under both the normal conditions and the stress conditions.

Short Communication

Gluten Exorphins are opioid peptides identified in enzymatic digests of gluten. The effects of Gluten Exorphins are still largely unknown. It has been shown that Gluten Exorphin B5 (Tyr-Gly-Gly-Trp-Leu) stimulates Prolactin secretion in male rats. In this study, we have evaluated the Prolactin response to Gluten Exorphin B4, another exorphin whose structure (Tyr-Gly-Gly-Trp) is identical to that of the NH(2)-terminal sequence of Gluten Exorphin B5. To this aim, five groups of male rats were given the following intravenous treatments: vehicle, Gluten Exorphin B5 3 mg kg-1 body weight, Gluten Exorphin B4 at the doses of 3, 6 and 9 mg kg-1 body weight. At the dose of 3 mg kg-1 body weight, Gluten Exorphin B5 induced a significant increase in Prolactin levels. Gluten Exorphin B4 could not modify Prolactin secretion, even when administered at doses three times higher than those effective for Gluten Exorphin B5. The present study: (1) indicates that Gluten Exorphin B4 does not modify Prolactin secretion in male rats; (2) confirms the ability of Gluten Exorphin B5 to exert a stimulatory action on Prolactin release; (3) suggests that the presence of the carboxy-terminal leucine in Gluten Exorphin B5 is essential for its action on Prolactin secretion.

Use of corn gluten feed and dried distillers grains plus solubles as a replacement for soybean meal and corn for supplementation in a corn silage-based stocker system

Corn gluten feed and dried distillers grains plus solubles (DDGS) were evaluated as replacements for soybean meal and ground ear corn when supplemented with corn silage during 2 yr of a beef cattle stockering program. Experiment 1: In YR 1, 104 steers (initial BW = 305 ± 30 kg), and in YR 2, 56 steers and 38 heifers (initial BW = 301 ± 32 kg) were stratified by weight and assigned to 1 of 9 groups. Each group was randomly assigned to 1 of 3 corn silage-based (75% of DM) diets supplemented with: i) corn gluten feed (CGF), ii) DDGS, or iii) soybean meal and ground ear corn (CSBM) at 25% of DM. On d 0, 28, 56, and 84, BW and BCS were recorded. Additionally, ribeye area, 12th rib fat thickness, intramuscular fat, and rump fat thickness were assessed via ultrasound on 9 (YR1) and 4 (YR 2) steers per pen that were randomly assigned as observational units. Average daily gain was greater (P < 0.05) for steers fed DDGS and CSBM compared with CGF (1.08, 1.08, and 0.94 kg/d, respectively). Average DMI (P < 0.05) was less for DDGS compared with CSBM with CGF intermediate (18.1, 18.8, 20.2 g/kg BW, respectively), and the resulting G:F was greatest for DDGS (P = 0.01). Cost per kilogram of BW gain was least for DDGS (P > 0.05). Ultrasound data indicated no differences (P ≥ 0.13) in predicted carcass traits among treatments. Experiment 2: Diets from Exp. 1 were subjected to in vitro digestion for incubation times of 0, 2, 4, 8, 16, 24, 48, and 72 h to estimate DM degradation, gas production kinetics, and CP fractions. The potentially degradable DM fraction was greater (P = 0.01) for CSBM compared with CGF and DDG. Total gas production and rate of gas production was not different among treatments (P > 0.42). Rumen degradable protein was greatest for CSBM and least for DDG (P = 0.001). These data indicate that DDGS can be used to replace soybean meal and corn in silage-based stocker systems to decrease feed costs without compromising animal performance and CGF may decrease animal performance.

Effects of peptide fractions with different isoelectric points from wheat gluten hydrolysates on lipid oxidation in pork meat patties

Wheat gluten hydrolysate (WGH) was fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing (autofocusing). Cooked pork patties were stored at 4 and 20 °C in the dark. WGH and autofocusing fractions suppressed the oxidation of lipids in the patties. The acidic (pI < 3.0) and basic (pI > 9.0) autofocusing fractions suppressed lipid oxidation in the cooked patties to a greater extent than other fractions and WGH. Each autofocusing fraction was evaluated by 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical scavenging activities, β-carotene bleaching, oxygen radical absorbance capacity, and Fe(2+) chelating assays; however, none of the in vitro assays predicted the suppressive effect of WGH on lipid oxidation in the cooked patties. These findings suggest that the microdistribution of peptides in food systems and their interaction with food matrix compounds play a significant role in the suppression of lipid oxidation in meat patties rather than radical scavenging activity.

Visualization of transepithelial passage of the immunogenic 33-residue peptide from alpha-2 gliadin in gluten-sensitive macaques

Background

Based on clinical, histopathological and serological similarities to human celiac disease (CD), we recently established the rhesus macaque model of gluten sensitivity. In this study, we further characterized this condition based on presence of anti-tissue transglutaminase 2 (TG2) antibodies, increased intestinal permeability and transepithelial transport of a proteolytically resistant, immunotoxic, 33-residue peptide from α₂-gliadin in the distal duodenum of gluten-sensitive macaques.

Methodology/Principal Findings

Six rhesus macaques were selected for study from a pool of 500, including two healthy controls and four gluten-sensitive animals with elevated anti-gliadin or anti-TG2 antibodies as well as history of non-infectious chronic diarrhea. Pediatric endoscope-guided pinch biopsies were collected from each animal's distal duodenum following administration of a gluten-containing diet (GD) and again after remission by gluten-free diet (GFD). Control biopsies always showed normal villous architecture, whereas gluten-sensitive animals on GD exhibited histopathology ranging from mild lymphocytic infiltration to villous atrophy, typical of human CD. Immunofluorescent microscopic analysis of biopsies revealed IgG+ and IgA+ plasma-like cells producing antibodies that colocalized with TG2 in gluten-sensitive macaques only. Following instillation in vivo, the Cy-3-labeled 33-residue gluten peptide colocalized with the brush border protein villin in all animals. In a substantially enteropathic macaque with “leaky” duodenum, the peptide penetrated beneath the epithelium into the lamina propria.

Conclusions/Significance

The rhesus macaque model of gluten sensitivity not only resembles the histopathology of CD but it also may provide a model for studying intestinal permeability in states of epithelial integrity and disrepair.

Effect of dietary soy protein on tumor necrosis factor productivity in macrophages from nephritic and hepatoma-bearing rats

The present study investigated the effect of dietary soy protein isolate (SPI) on tumor necrosis factor-alpha (TNF) productivity in peritoneal macrophages from nephritic and hepatoma-bearing rats. Dietary SPI significantly inhibited the elevated production of TNF by lipopolysaccharide-stimulated macrophages in nephritic and hepatoma-bearing rats compared with dietary casein, while it exerted no influence on the TNF productivity in normal rats. Removal of the minor components contained in SPI by ethanol extraction could significantly or partially restore the reduced TNF production caused by SPI in nephritic and hepatoma-bearing rats, respectively. These results suggest that dietary SPI could suppress the enhanced productivity of TNF associated with the progression of nephritis and hepatoma, and some factors existing in the ethanol extract of SPI are suggested to be involved in suppressing TNF productivity by macrophages.

Antioxidant activity of some protein hydrolysates and their fractions with different isoelectric points

Antioxidant activities of commercially available enzymatic hydrolysates of milk and plant proteins were examined. Among them, soy protein and wheat gluten hydrolysates showed strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and antioxidation activity against linoleic acid oxidation in emulsion systems. Peptide fractions with higher antioxidant activities than crude enzymatic hydrolysates of gluten and soy protein were prepared without toxic solvents and reagents. Peptides in these plant protein hydrolysates were fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing without adding chemically synthesized carrier ampholytes, which is termed autofocusing. The acidic fractions from both protein hydrolysates showed stronger DPPH radical scavenging activities than the basic fractions, while the basic fractions strongly suppressed 2,2'-azobis (2-amidinopropane) dihydrochloride-induced oxidation of linoleic acid in an emulsion system. These acidic and basic peptide fractions would be useful to examine the mechanism underlying the antioxidant activities of peptides in food.

Enhancement of dietary protein digestion by conjugated bile acids

BACKGROUND & AIMS

Conjugated bile acids promote absorption of dietary lipids by solubilizing them in mixed micelles. Bile acids are not considered to facilitate the digestion of other nutrients.

METHODS

The effect of conjugated bile acids on the rate of protein hydrolysis by trypsin and chymotrypsin was examined in vitro. Common dietary proteins and 2 bacterial glutenases (proposed oral therapies for celiac sprue) were proteolyzed in the absence or presence of a 10 mmol/L conjugated bile acid mixture, simulating human bile composition. Lipolysis products (monoolein) and fatty acid were also evaluated to simulate postprandial intestinal contents.

RESULTS

Conjugated bile acids dramatically enhanced the proteolysis of several dietary proteins, including beta-lactoglobulin, bovine serum albumin, myoglobin, and a commercially available dietary protein supplement. For beta-lactoglobulin, a cow's milk allergen that is resistant to pepsin cleavage, bile acids enhanced its proteolysis by pancreatic proteases even after incubation under gastric conditions. Exposure of prolyl endopeptidases to bile acids made them more susceptible to pancreatic proteases under simulated intestinal conditions. The conjugated bile acid effect was most pronounced in the presence of dihydroxy bile acids and was observable at bile concentrations below the critical micellar concentration but to a much greater extent at concentrations above the critical micellar concentration.

CONCLUSIONS

We propose that, in addition to promoting lipid absorption, conjugated bile acids affect the digestion and assimilation of dietary proteins by accelerating hydrolysis by pancreatic proteases. These findings have implications for intraluminal protein breakdown and assimilation in the upper small intestine.

Effects of stocking rate and corn gluten feed supplementation on performance of young beef cows grazing winter-stockpiled tall fescue-red clover pasture1

A winter grazing experiment was conducted to evaluate the effects of stocking rate and corn gluten feed supplementation on forage mass and composition and the BW and BCS of bred 2-yr-old cows grazing stockpiled forage during winter. Two 12.2-ha blocks containing Fawn, endophyte-free, tall fescue and red clover were each divided into 4 pastures of 2.53 or 3.54 ha. Hay was harvested from the pastures in June and August of 2003 and 2004, and N was applied at 50.5 kg/ha at the initiation of stockpiling in August. On October 22, 2003, and October 20, 2004, twenty-four 30-mo-old Angus-Simmental and Angus cows were allotted by BW and BCS to strip-graze for 147 d at 0.84 or 1.19 cow/ha. Eight similar cows were allotted to 2 dry lots and fed tall fescue-red clover hay ad libitum. Corn gluten feed was fed to cows in 2 pastures to maintain a mean BCS of 5 (9-point scale) at each stocking rate and in the dry lots (high supplementation level) or when weather prevented grazing (low supplementation level) in the remaining 2 pastures at each stocking rate. Mean concentrations of CP in yr 1 and 2 and IVDMD in yr 2 were greater (P < 0.10) in hay than stockpiled forage over the winter. At the end of grazing, cows fed hay in dry lots had greater (P < 0.05) BCS in yr 1 and greater (P < 0.10) BW in yr 2 than grazing cows. Grazing cows in the high supplementation treatment had greater (P < 0.10) BW than cows grazing at the low supplementation level in yr 1. Cows in the dry lots were fed 2,565 and 2,158 kg of hay DM/cow. Amounts of corn gluten feed supplemented to cows in yr 1 and 2 were 46 and 60 kg/ cow and did not differ (P = 0.33, yr 1; P = 0.50, yr 2) between cows fed hay or grazing stockpiled forage in either year. Estimated production costs were greater for cows in the dry lots because of hay feeding.

Randomised, controlled, cross-over trial of soy protein with isoflavones on blood pressure and arterial function in hypertensive subjects

OBJECTIVE

To examine the effects of dietary soy/isoflavones on 24 hr blood pressure profiles and arterial function [systemic arterial compliance (SAC), pulse wave velocity (PWV) and brachial arterial flow mediated vasodilation (FMD)] compared to non legume-based plant protein without isoflavones, in hypertensive subjects.

DESIGN

In a 6 month double-blind, placebo controlled, cross-over trial, 41 hypertensive subjects (26 men, 15 postmenopausal women), 30-75 years, received soy cereal (40 g soy protein, 118 mg isoflavones) and gluten placebo cereal, each for 3 months.

RESULTS

Thirty-eight subjects completed protocol with results expressed as mean or mean change (+/-SEM) with each intervention. Soy increased urinary isoflavones (daidzein: 8-fold; genistein: 8-fold; equol: 9-fold; ODMA: 18-fold) with no change during gluten placebo. There was no difference in the change in individual 24 hr ambulatory BP parameters (SBP: 2 +/- 2 vs -1 +/- 1 mmHg, p = 0.21; DBP: 1 +/- 1 vs -1 +/- 1 mmHg, p = 0.06) central BP (cSBP: -4 +/- 2 vs 0 +/- 2 mmHg, p = 0.2) or the change in arterial function (FMD: 0.3 +/- 0.5 vs -0.2 +/- 0.5%, p = NS; SAC: 0.02 +/- 0.02 vs -0.02 +/- 0.02 U/mmHg, p = NS; PWV central: -0.2 +/- 0.2 vs 0.0 +/- 0.2 m/sec, p = NS; PWV peripheral: 0.01 +/- 0.3 vs -0.4 +/- 0.4 m/sec, p = NS) noted between interventions. Analysis of the area under curve of 24 hr BP outputs demonstrated that soy protein compared to gluten protein resulted in higher 24 hr systolic BP by 2.3 mmHg (p = 0.003), a higher daytime systolic BP by 3.4 mmHg (p = 0.0002) and a higher daytime diastolic BP by 1.4 mmHg (p = 0.008). Overall 24 hr diastolic BP, night systolic BP and night diastolic BP were not significantly different between groups. Furthermore, soy protein compared to gluten protein resulted in higher 24 hr heart rates by 3.5 bpm (p < 0.0001).

CONCLUSIONS

In hypertensive subjects, compared to gluten placebo, soy dietary supplementation containing isoflavones had no effect on arterial function, on average 24 hr ambulatory blood pressure parameters or central blood pressure in men and women with hypertension. Area under the curve of 24 hr profiles demonstrated that daytime BP was higher after soy compared to gluten.

A unique dendritic cell subset accumulates in the celiac lesion and efficiently activates gluten-reactive T cells

BACKGROUND & AIMS

Celiac disease is a chronic inflammation of the duodenal mucosa driven by gluten-reactive T cells restricted by the disease-associated HLA-DQ2 molecule. The mechanisms that regulate the activation of mucosal T cells are, however, understood poorly. The aim of this study was to identify the antigen-presenting cells that are responsible for the activation of gluten-reactive T cells in the celiac lesion.

METHODS

Intestinal biopsy specimens obtained from untreated and treated celiac patients and normal controls were either snap-frozen directly or incubated for 24 hours with or without gluten peptides. Cryosections were subjected to multicolor immunofluorescence applying monoclonal antibodies to a range of antigen-presenting cell markers. Macrophages and dendritic cells were isolated from enzymatically digested small intestinal biopsies of untreated patients and incubated with gluten-reactive T-cell clones to measure their antigen-presenting capacity.

RESULTS

HLA-DQ2+ cells in the normal duodenal mucosa consisted of 2 distinct cell populations: about 80% were CD68+ DC-lysosome intercellular adhesion molecule-3-grabbing nonintegrin+ macrophages and 20% were CD11c+ dendritic cells. Importantly, the CD11c+ dendritic cells accumulated in the celiac lesion and revealed an activated phenotype expressing CD86 and DC-specific-associated membrane protein. Moreover, when isolated from challenged biopsy specimens, the CD11c+ dendritic cells efficiently activated gluten-reactive T cells.

CONCLUSIONS

Our results suggest that a unique subset of dendritic cells are responsible for local activation of gluten-reactive T cells in the celiac lesion.

Appetite regulatory hormone responses to various dietary proteins differ by body mass index status despite similar reductions in ad libitum energy intake

CONTEXT

Although dietary protein produces higher acute satiety relative to carbohydrate, the influence of protein source and body mass index (BMI) has not been clearly described.

OBJECTIVE

The objective of the study was to assess postprandial responses to different protein sources, compared with glucose, in males with normal and high BMI.

DESIGN

This was a randomized, crossover study of four preloads followed by blood sampling (+15, 30, 45, 60, 90, 120, 180 min) and buffet meal.

SETTING

The study was conducted at an outpatient clinic.

PARTICIPANTS

The study population included 72 men, with a BMI range 20.6-39.9 kg/m(2).

INTERVENTIONS

Interventions consisted of liquid preloads (1.1 MJ, 450 ml) containing 50 g whey, soy, gluten, or glucose.

MAIN OUTCOME MEASURES

Fasting and postprandial plasma glucose, insulin, ghrelin, glucagon-like peptide-1 (GLP-1) and cholecystokinin (n = 38), ad libitum energy intake, and appetite ratings were measured.

RESULTS

Energy intake was 10% lower after all protein preloads, compared with the glucose treatment (P < 0.05), independent of BMI status and protein type. All protein loads prolonged the postprandial suppression of ghrelin (P < 0.01) and elevation of GLP-1 (P < 0.01) and cholecystokinin (P < 0.05). Fasting GLP-1 concentrations [overweight, 17.5 +/- 1.3; lean, 14.7 +/- 0.1 pg/ml (5.2 +/- 0.4 and 4.4 +/- 0.1 pmol/liter, respectively); P < 0.001] and postprandial responses (P = 0.038) were higher in overweight subjects.

CONCLUSIONS

Whey, soy, and gluten similarly tend to reduce ad libitum food intake 3 h later in lean and overweight males relative to glucose. Postprandial ghrelin, GLP-1, insulin, and cholecystokinin may contribute to this higher satiety after protein consumption. GLP-1 concentrations are increased in overweight subjects, which may affect satiety responses in this group.

The changing immunological paradigm in coeliac disease

When coeliac disease is referred to as an inflammatory disorder, this may detract from its true nature. Activation of innate and adaptive immunity takes place in the mucosal lesion, but the tissue reaction is not that of classical inflammation. In fact, coeliac disease contrasts strikingly with typical inflammatory bowel disorders such as ulcerative colitis and Crohn's disease. The coeliac lesion apparently reflects, in the main, immune-driven remodelling of mucosal architecture with only a minor inflammatory component - initially most likely resulting from innate signals. Complement split products might be one of several potential initial hits that lead to activation of lamina propria and epithelial cells with release of mediators such as interleukin-15. This cytokine appears to stimulate potentially pathogenic intraepithelial lymphocytes. In genetically susceptible individuals, such early innate events could turn into persistent pathogenic signalling with subsequent adaptive cellular and humoral immunopathology resulting in a chronic lesion. Nevertheless, mucosal homeostasis is surprisingly well preserved as signified by the remarkable dominance of plasma cells that produce dimeric immunoglobulin A as a basis for enhanced secretory immunity. This shows that the microvascular endothelium in the lesion largely maintains its 'gatekeeper' function for mucosal immune cells - in striking contrast to the 'promiscuous' situation in inflammatory bowel disease. Altogether, a two-signal model is emerging for the pathogenesis of coeliac disease - signal 1 generated by innate immunity and signal 2 by adaptive immunity. Hence, there is currently an increased focus on immune activation in the epithelial compartment rather than on changes in the microvasculature as a basis for classical inflammation.

Wheat-dependent exercise-induced anaphylaxis in mice is caused by gliadin and glutenin treatments

Various foods may be associated with food-dependent exercise-induced anaphylaxis (FDEIAn). However, although the most frequently reported cause of FDEIAn has been wheat, the mechanism of FDEIAn for wheat has remained largely uninvestigated. To investigate the effect of wheat-fractionated proteins on FDEIAn, female B10.A mice (16-20 g) were divided into four groups; i.e. salt-soluble (S-group), gliadin-rich (GLI-group), and glutenin-rich (GLU-group)-sensitized mice, and unsensitized mice. The three sensitized groups were run on a treadmill after oral intake of each wheat-fractionated protein. The mice showed a significant increase in serum IgE, especially in the GLI- and GLU-group. After oral administration of each wheat-fractionated protein, the running time until exhaustion was remarkably shorter for the GLI- and GLU-group than for the S-group and unsensitized mice. The level of intestinal erosion was higher in all the sensitized mice than that in the unsensitized ones after exhaustive running. Furthermore, moderate exercise for 30 min after oral ingestion of each wheat-fractionated protein also induced intestinal erosion in the GLI- and GLU-group. In addition, we observed leaking of gliadin and glutenin proteins out of the intestine into the liver. These results indicated that the main factor involved in wheat-dependent exercise-induced anaphylaxis might be the gliadin and glutenin in wheat proteins.

Optimal wet corn gluten and protein levels in steam-flaked corn-based finishing diets for steer calves1

A feeding trial evaluated the hypothesis that wet corn gluten feed would improve growth performance of cattle fed steam-flaked corn-based finishing diets and supply required degradable intake protein (DIP). The trial used 360 steer calves (initial BW = 288 +/- 11 kg) housed in 36 pens for 166 d in an incomplete 4 x 3 factorial arrangement of treatments. Pens of steers were assigned to treatments according to a completely randomized design (four replicates per treatment combination). Treatments were wet corn gluten feed (0, 20, 30, or 40% of dietary DM) and CP (13.0, 13.7, or 14.4% of dietary DM) via supplemental urea as DIP. The 0% wet corn gluten feed treatment included only the 13.7% CP diet, and the 40% wet corn gluten feed treatment included only the 13.7 and 14.4% CP diets. Final dietary DIP concentration was 9.0% for 0% wet corn gluten feed; 8.7, 9.5, and 10.2% for 20% wet corn gluten feed; 9.0, 9.7, and 10.3% DIP for 30% wet corn gluten feed; and 10.0 and 10.6% for 40% wet corn gluten feed. Hot carcass weight, ADG, DMI, and G:F responded quadratically (P < or = 0.05) to wet corn gluten feed. The 20, 30, and 40% wet corn gluten feed treatments increased ADG by 7, 6, and 3% and increased DMI by 4, 5, and 5%, respectively, relative to the 0% wet corn gluten feed treatment. Feed efficiency was 102, 101, and 98% of the 0% wet corn gluten feed treatment for 20, 30, and 40% wet corn gluten feed, respectively. Hot carcass weight, ADG, and G:F increased linearly (P < or = 0.05) in response to increased DIP. Nonlinear analysis for DIP over the combined 20 and 30% wet corn gluten feed treatments indicated a DIP requirement of 9.6% of DM for ADG and 9.2% of DM for G:F, corresponding to 14.6 and 14.3% CP for 20% wet corn gluten feed and 14.8 and 14.5% CP for 30% wet corn gluten feed, respectively. Fat thickness, marbling, LM area, and USDA yield grade were not affected (P = 0.12 to 0.99) by wet corn gluten feed or CP. These results show that the inclusion rate of wet corn gluten feed for maximizing ADG and G:F in steam-flaked corn-based finishing diets is approximately 20% of DM. The DIP requirement determined in this trial averaged 9.4% of DM.

Dietary protein source affects lipid metabolism in the European seabass (Dicentrarchus labrax)

The study was undertaken to evaluate the effects of dietary protein sources on lipogenesis and fat deposition in a marine teleost, the European seabass (Dicentrarchus labrax). Four isonitrogenous (crude protein (CP, Nx6.25), 44% DM) and isoenergetic (22-23 kJ/g DM) diets were formulated to contain one of the following as the major protein source: fish meal (FM), one of two soy protein concentrates (SPC) and corn gluten meal (CGM). Apparent digestibility coefficients of the diets and raw ingredients, as well as soluble nitrogen (ammonia and urea) and phosphorus excretion were measured. Growth rates of seabass fed plant protein-based diets were significantly lower than those fed fish meal based diet. The protein utilisation was strongly correlated to the dietary essential amino acids index. Measurements of N excretion (ammonia and urea nitrogen) confirmed these data. Daily fat gain at the whole body level ranged between 1.1 to 1.7 g/kg BW, with the highest values being recorded in fish fed the fish meal based diet. Levels of plasma triglycerides and cholesterol were lower in fish fed soy protein diets than in those fed the diet solely based on fish meal. Soy protein rich diets decreased the activities of selected hepatic lipogenic enzymes (glucose 6-phosphate dehydrogenase, malic enzyme, ATP-citrate lysase, acetylcoenzyme A carboxylase and fatty acid synthetase). Highest lipogenic enzyme activities where found in fish fed the fish meal diet, except for fatty acid synthetase which was increased in seabass fed the corn-gluten meal based diets. Overall data suggest that dietary protein sources affects fat deposition and the lipogenic potential in European seabass.

Gut mucosal granulocyte activation precedes nitric oxide production: studies in coeliac patients challenged with gluten and corn

BACKGROUND AND AIMS

To elucidate the dynamics of nitric oxide (NO) production induced by rectal gluten challenge and the relation between NO production and mucosal granulocyte activation.

SUBJECTS AND METHODS

Release of rectal NO was measured in 13 patients with coeliac disease and in 18 controls before and after rectal wheat gluten challenge. Rectal gas was collected with a rectal balloon using a newly developed instrument/technique, the "mucosal patch technique". The instrument allows simultaneous measurements of concentrations of granulocyte mediators in the rectal mucosa. We measured myeloperoxidase (MPO), eosinophil cationic protein (ECP), and histamine. For comparison, we made similar measurements after corn (maize) gluten challenge.

RESULTS

In all coeliac patients rectal NO concentration increased after gluten challenge and reached a peak after 15 hours (mean 9464 (SEM 2393) parts per billion (ppb); range 250-24982). The maximum MPO and ECP increase occurred five hours after challenge. A correlation was found between mucosal MPO and NO production at 15 hours. Six of the patients showed an increase in NO production 15 hours after rectal corn gluten challenge but this was much smaller than after gluten challenge. No increases were seen in the control group after either challenge.

CONCLUSION

Mucosal activation of neutrophils and eosinophils precedes pronounced enhancement of mucosal NO production after rectal wheat gluten challenge in patients with coeliac disease. Some of our coeliac patients displayed signs of an inflammatory reaction, as measured by NO and granulocyte markers, after rectal corn gluten challenge.

Dietary protein source determines the degree of hypertension and renal disease in the Dahl salt-sensitive rat

Previous studies demonstrated that a whole-grain diet attenuated sodium-dependent hypertension and renal disease in Dahl salt-sensitive rats from the colony at the Medical College of Wisconsin (Dahl SS/Mcw rats) compared with rats maintained on a purified AIN-76A diet. The present experiments determined which component(s) of the grain diet prevented renal and cardiovascular disease. Male SS/Mcw rats were maintained on isocaloric diets identical to AIN-76A, except the source of protein (wheat gluten for casein), carbohydrate (wheat flour for sucrose), or fat (soybean oil for corn oil) was substituted in separate diets. Rats were maintained on the different diets from weaning and studied after 3 weeks on a high-salt (4.0% NaCl) diet. Substitution of the carbohydrate in the diet did not affect body weight, arterial pressure, or renal disease. Replacement of casein with wheat gluten significantly reduced body weight (258+/-7 versus 353+/-3 grams), mean arterial pressure (133+/-2 versus 153+/-2 mm Hg), and albumin excretion (9+/-1 versus 50+/-7 mg/d) to levels of rats fed the whole-grain diet (n=7 to 16/group). Replacement of the fat in the diet increased arterial pressure without affecting body weight or albumin excretion. The results of the present study indicate that dietary components other than sodium play an important role in the development of hypertension and renal disease in the Dahl SS/Mcw rat.

Comparison of wheat gluten and spray-dried animal plasma in diets for nursery pigs1,2

Five experiments were conducted to determine the effects of different wheat gluten (WG) sources (Source 1 = enzymatically hydrolyzed, Source 2 = nonmodified ring-dried, Source 3 = spray-dried, and Source 4 = flash-dried) on growth performance of nursery pigs compared with soybean meal (SBM), spray-dried animal plasma (SDAP), or other specialty protein sources. In Exp. 1, pigs (n = 220, initially 6.1 +/- 2.5 kg) were fed a control diet containing (as-fed basis) 6% SDAP or WG Source 1 or 2. The WG and l-lysine*HCl replaced 50 or 100% of the SDAP. From d 0 to 21, increasing WG (either source) decreased ADG and ADFI (linear, P < 0.01), but improved (linear, P < 0.02) G:F. In Exp. 2, pigs (n = 252, initially 6.2 +/- 3.0 kg) were fed a negative control diet containing no SDAP or WG, diets containing (as-fed basis) 9% WG Source 1 or 5% SDAP, or combinations of WG and SDAP where WG and l-lysine*HCl replaced 25, 50, or 75% of SDAP. From d 0 to 14, pigs fed increasing WG had decreased ADG (linear, P < 0.05). In Exp. 3, pigs (n = 240, initially 7.0 +/- 2.5 kg) were fed a negative control diet, a diet containing (as-fed basis) either 3, 6, 9, or 12% WG Source 3, or a positive control diet containing 5% SDAP. The diets containing 9% WG and 5% SDAP had the same amount of SBM. From d 0 to 7, pigs fed 5% SDAP had greater (P < 0.04) ADG than pigs fed the diet containing 9% WG. From d 0 to 14, increasing WG had no effect on ADG, ADFI, or G:F. In Exp. 4, pigs (n = 200, initially 6.0 +/- 2.4 kg) were fed a negative control diet, the control diet with (as-fed basis) 4.5 or 9.0% WG Source 1, or the control diet with 2.5 or 5.0% SDAP. Diets containing WG and SDAP had similar SBM levels. From d 0 to 7 and 0 to 14, increasing SDAP tended to improve (linear, P < 0.06) ADG, but increasing WG had no effect. In Exp. 5, 170 barrows and gilts (initially 7.5 +/- 2.8 kg) were used to determine the effects of WG Source 1 and 4 compared with select Menhaden fish meal or spray-dried blood cells and a negative control diet (SBM) on the growth performance of nursery pigs from d 5 to 26 postweaning (d 0 to 21 of experiment). No differences were found in ADG or G:F, but pigs fed the diet containing (as-fed basis) 2.5% spray-dried blood cells had greater ADFI than pigs fed the negative control from d 0 to 21. Wheat gluten source had no effect on ADG, ADFI, or G:F. The results of these studies suggest that increasing WG in diets fed immediately after weaning did not improve growth performance relative to SBM or SDAP.

Wheat gluten causes dendritic cell maturation and chemokine secretion

Wheat gluten causes gut inflammation in genetically predisposed individuals. We tested the hypothesis that wheat gluten is not only a target of adaptive immunity, but also modulates the function of APC. Dendritic cells (DC) derived from the bone marrow of BALB/c mice were exposed to chymotrypsin-treated wheat gluten. This induced DC maturation as estimated by all surface markers tested (MHC class II, CD40, CD54, and CD86). The effect was dose dependent, and, at 100 microg/ml gluten matched that caused by 10 ng/ml LPS. A role of endotoxin contamination was ruled out by demonstrating the resistance of wheat gluten effects to LPS antagonist polymyxin B. DC from LPS nonresponder strain C3H/HeJ were affected by wheat gluten, but not by LPS. Proteinase K-digested wheat gluten was unable to stimulate DC maturation. Wheat gluten induced a unique secretion pattern of selected cytokines and chemokines in DC. Classic pro- or anti-inflammatory mediators were not produced, in contrast to LPS. Rather, chemokines MIP-2 and keratinocyte-derived cytokine were secreted in large amounts. We conclude that wheat gluten lowers the threshold for immune responses by causing maturation of APC, by attracting leukocytes and increasing their reactivity state. In the presence of an appropriate genetic predisposition, this is expected to increase the risk of adverse immune reactions to wheat gluten or to other Ags presented.

Gluten of spelt wheat (Triticum aestivum subspecies spelta) as a source of peptides promoting viability and product yield of mouse hybridoma cell cultures

The enzymic hydrolysate of gluten from spelt wheat (Triticum aestivum subsp. spelta), an ancient protein-rich wheat subspecies, was subjected to repeated chromatography runs on the small pore size exclusion chromatography matrix, Biogel P-2. Two small peptide fractions were purified by rechromatography. The amino acid analyses carried out upon total hydrolysis of these fractions have shown a very high proportion of glutamic acid/glutamine, leucine, and methionine. The biological activity of the peptide fractions was tested on a model hybridoma at a concentration range from 0.02 to 0.2%. The most striking effect of peptide fractions, apparent even at the lowest concentrations tested, was a significantly higher persistence of viable cells on day 6, i.e., at the decline phase of the cultures. Culture viability values in the presence of peptide fractions were 64-74%, in comparison with 56% in the control culture. The results of this work are consistent with the concept that peptide molecules may act as antiapoptotic agents, survival factors, rather than serving as metabolic substrates.

Dietary treatment of gluten ataxia

BACKGROUND

Gluten ataxia is an immune mediated disease, part of the spectrum of gluten sensitivity, and accounts for up to 40% of cases of idiopathic sporadic ataxia. No systematic study of the effect of gluten-free diet on gluten ataxia has ever been undertaken.

OBJECTIVE

To study the effect of gluten-free diet on patients presenting with ataxia caused by gluten sensitivity.

METHODS

43 patients with gluten ataxia were studied. All were offered a gluten-free diet and monitored every six months. All patients underwent a battery of tests to assess their ataxia at baseline and after one year on diet. Twenty six patients (treatment group) adhered to the gluten-free diet and had evidence of elimination of antigliadin antibodies by one year. Fourteen patients refused the diet (control group). Three patients had persistently raised antigliadin antibodies despite adherence to the diet and were therefore excluded from the analysis.

RESULTS

After one year there was improvement in ataxia reflected in all of the ataxia tests in the treatment group. This was significant when compared with the control group. The diet associated improvement was apparent irrespective of the presence of an enteropathy.

CONCLUSIONS

Gluten ataxia responds to a strict gluten-free diet even in the absence of an enteropathy. The diagnosis of gluten ataxia is vital as it is one of the very few treatable causes of sporadic ataxia.

Opioid receptor ligands derived from food proteins

During the last two decades a variety of food protein fragments has been demonstrated to elicit biological effects in various in vitro or in vivo test systems. A considerable part of these bioactive peptides are opioid receptor ligands, which may be regarded as exogenous supplements to the endogenous opioidergic systems of the human organism. Most of these food-derived opioid receptor ligands are fragments of the milk proteins alpha-, beta- or kappa-casein, alpha-lactalbumin, beta-lactoglobulin or lactotransferrin; however, also wheat gluten, rice albumin, bovine serum albumin or hemoglobin, i.e. possible constituents of meat, and even a protein from spinach could be demonstrated to contain fragments behaving like opioid receptor ligands. Practically all of these compounds display opioid agonist activity; only very few of them behave like opioid antagonists. Bioactive food protein derivatives have been termed " food hormones", which implies that these compounds display their bioactivities when released from food constituents, i.e. from their precursor molecules due to the action of gastrointestinal enzymes. The critical point in case of food protein-derived opioid receptor ligands is that only a minority of their bioactive effects demonstrated as yet has been observed upon oral or intragastric administration of these peptides or their precursor proteins and that most of these studies have been performed in animals. Thus, in terms of "evidence-based dietary supplementation" more studies are needed to prove effects of food protein-derived opioid receptor ligands or their precursors after oral administration in humans and, moreover, to prove a benefit for the consumer's organism.

Evaluation by SDS-Page and immunoblotting of residual antigenicity in gluten-treated wine: a preliminary study

Hydrolyzed gluten could be a suitable alternative to animal proteins in the wine clarification process, but the residual proteins could constitute a risk for subjects suffering from celiac disease or allergy to cereals. The aim of this study was to investigate possible traces of gluten in treated wine and to assess its antigenicity in commercial products. The presence of gluten in treated wine was evaluated by an electrophoretic method [sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE)] and its immunoreactivity was evaluated by immunoblotting. No traces of protein were found in untreated samples. A small quantity of protein was detected in treated wine but this produced no significant immunochemical reaction. In an experimental clarification process, a protein fraction was detectable in untreated samples and in the first stages of the clarification process. However, there was no significant gluten-associated immunochemical reaction in clarified wine samples, confirming strong binding between the clarifying agent and the phenolic fraction. In conclusion, the clarifying process strongly reduced the amount of protein material, at least in red wines. Under the most restrictive tests of the presence of gluten in the product, the predictable residue of gluten in wine was safe for celiac subjects. For allergic subjects the data are less conclusive because there is no known limit for allergic reactions, but clear labeling of the method of treating the wine should also protect this group of consumers.

HLA-DQ determines the response to exogenous wheat proteins: a model of gluten sensitivity in transgenic knockout mice

We have investigated the genetic basis of the immune response to dietary gluten in HCD4/DQ8 and HCD4/DQ6 double transgenic mice. Mice were immunized with gluten i.p. or individual peptides s.c. and spleen or draining lymph node T cells were challenged in vitro. Strong proliferative responses to gluten were seen in the HCD4/DQ8 mice, whereas the HCD4/DQ6 mice responded to gluten poorly. A series of overlapping peptides spanning gliadin were synthesized. The HCD4/DQ8 mice reacted to many of the individual peptides of gliadin, while the HCD4/DQ6 mice were relatively unresponsive. T cells isolated from HCD4/DQ8 mice also responded well to modified (deamidated) versions of the gliadin peptides, whereas HCD4DQ6 mice did not. The T cell response to gluten was CD4 dependent and DQ restricted and led to the production of cytokines IL-6, TGF-beta, and IL-10. Finally, intestinal lymphocytes isolated from gluten-fed HCD4/DQ8 mice displayed an activated phenotype. These data suggest that this HLA class II transgenic murine model of gluten sensitivity may provide insight into the initiation of the MHC class II-restricted gluten sensitivity in celiac disease.

Protein is more potent than carbohydrate for reducing appetite in rats

The purpose of this study was to characterize further the effects of loads of protein versus carbohydrate on subsequent food intake in rats. We used an intraoral cannula to deliver isoenergetic isovolumic loads, in a tightly controlled time frame allowing for both metabolic responses and orosensory components of the load. Our results showed that the gluten load (GLT-100%) induced a greater depression in food intake than an isocaloric wheat starch load (GLT-0%). The types of protein used in the load (total milk protein vs. GLT) did not seem to influence their appetite-suppressive effect. There was a dose-dependent effect of the satiating effects of the protein loads, the GLT-100% load being more effective than either the GLT-35% or GLT-50% loads. Pattern analysis of the meal following the load suggested that animals were more satiated by protein, at least when loads contained 35% or 50% of protein, than by carbohydrate. At least 1 day was necessary before we saw a significant decrease in the energy intake following the protein loads. Thus, the animals had to learn the postingestive effects of the loads before the response stabilized. Taken together, the present results confirm that protein has a greater satiating effect than carbohydrate and extend these results by revealing that the larger the proportion of protein in the food, the larger the satiating effect, and that the quality of protein does not seem to play a significant role.

Oral exposure to diabetes-promoting food or immunomodulators in neonates alters gut cytokines and diabetes

Disease development in diabetes-prone BB rats is modified by the type of diet fed after weaning. The aim of this investigation was to determine whether exposure during the first week of life to antigens from a known diabetes-promoting diet (NIH-07) could modify diabetes incidence and, if so, to what extent this occurs via alterations in systemic T-cell reactivity, gut cytokines, or islet infiltration. Diabetes-prone BB (BBdp) rats were hand-fed twice daily between age 4 and 7 days with vehicle, a hydrolyzed casein (HC)-based infant formula, Pregestimil (PG), PG + cereal-based NIH-07 diet, PG + lipopolysaccharides (LPS) or PG + LPS + silica. After weaning, they were fed either an NIH-07 diet or a semipurified HC (diabetes-retardant) diet until 150 days. In separate studies, 5-day-old BBdp rat pups were administered the aforementioned treatments, and expression of intestinal mRNA for gamma-interferon (IFN-gamma) or transforming growth factor-beta (TGF-beta) was quantified using reverse transcriptase-polymerase chain reaction. The effect of early oral treatment with NIH-07 or PG on systemic T-cell reactivity was evaluated using footpad swelling delayed-type hypersensitivity (DTH) and the popliteal lymph node assay. Oral exposure of neonates to a complex mixture of antigens from the diabetes-promoting diet delayed onset of diabetes (79 vs. 88 days) and prevented disease in approximately one-third of animals. A similar protective effect was seen for neonatal exposure to wheat gluten in animals subsequently weaned onto a semipurified wheat gluten diet. By contrast, LPS-treated neonates displayed more severe insulitis and developed diabetes at an increased rate, which was significantly suppressed by co-administration of silica particles. The protective effect of early exposure to diabetogenic diets was not associated with significant reduction of islet infiltration, and there was no impact on the DTH response to food antigens. However, whereas diabetes-resistant BBc rats developed systemic tolerance to NIH-07 antigens fed chronically, BBdp rats did not. The lack of effect of the early oral antigen regimen on the DTH reaction in the footpad, a classic Th1-mediated reaction, suggests little effect on systemic T-cell reactivity. However, local effects were observed in the small intestine. Oral exposure to diabetes-promoting food antigens or LPS downregulated the Th1 cytokine IFN-gamma and decreased the IFN-gamma/TGF-beta ratio. Thus, oral exposure to diabetes-promoting food antigens and immune modulators in neonates can modify diabetes expression in association with changes in local cytokine balance in the gut.

Dietary protein peptic hydrolysates stimulate cholecystokinin release via direct sensing by rat intestinal mucosal cells

We previously demonstrated that a peptic hydrolysate of guanidinated casein strongly stimulates exocrine pancreatic secretion in chronic bile-pancreatic juice-diverted rats and cholecystokinin (CCK) release from dispersed rat intestinal mucosal cells. These results reveal that the chemically modified protein hydrolysate stimulates CCK secretion and increases pancreatic secretion by a luminal trypsin-independent direct action on the small intestine. In the present study, we examined the direct effect of peptic hydrolysates of naturally occurring dietary proteins, casein, soybean protein isolate (SPI), egg white, and wheat gluten on CCK release under in vitro trypsin-independent conditions. All protein hydrolysates significantly stimulated CCK release from dispersed rat intestinal mucosal cells. Among the hydrolysates treated, SPI hydrolysate was the most effective in stimulating CCK release. The potential of SPI hydrolysate to stimulate CCK release was increased by long-term peptic digestion. However, an SPI-like amino acid mixture did not effect CCK release. In conclusion, peptic hydrolysates of commonly ingested dietary proteins stimulate CCK release via trypsin-independent direct sensing by intestinal mucosal cells.

Flow-cytometric detection of lactase expression in normal and coeliac intestinal epithelium

OBJECTIVE

Enterocyte lactase expression is a useful marker of gluten toxicity. In this study, the technique of flow cytometry was evaluated to quantify lactase expression in coeliac disease (CD).

METHODS

Duodenal enterocyte suspensions were obtained from 23 patients with CD, four patients with dermatitis herpetiformis (DH), and 33 control subjects. The percentage of enterocytes that reacted with anti-lactase monoclonal antibody was determined by flow cytometry. In some subjects, organ culture of duodenal biopsies in the presence of various stimuli (including gluten fractions) was performed before enterocyte analysis.

RESULTS

This study demonstrated that lactase expression can be readily investigated semi-quantitatively using flow cytometry. Moreover, the level of expression correlated with the extent of mucosal damage in gluten-sensitive individuals. However, in organ culture experiments, lactase expression did not change in the presence of gluten or after marked T-cell activation for 48 h.

CONCLUSIONS

Measurement of enterocyte lactase expression by flow cytometry is a useful adjunctive test in the diagnosis and monitoring of gluten-sensitive enteropathy. However, lactase expression is not a suitable marker of gluten-induced toxicity in organ culture.

High-protein diets in hyperlipidemia: effect of wheat gluten on serum lipids, uric acid, and renal function

BACKGROUND

The metabolic effects of diets high in vegetable protein have not been assessed despite much recent interest in the effect of soy proteins in reducing serum cholesterol.

OBJECTIVE

We assessed the metabolic effects of diets high in vegetable protein (specifically, wheat gluten) on serum lipids, uric acid concentrations, and renal function.

DESIGN

Twenty hyperlipidemic men and women consumed isoenergetic test (high-protein) and control metabolic diets for 1 mo in a randomized crossover design. In the high-protein diet, 11% of the total dietary energy from starch in the control bread was replaced by vegetable protein (wheat gluten), resulting in 27% of total energy from protein compared with 16% in the control diet. In other respects, the 2 diets were identical.

RESULTS

Compared with the control, the high-protein diet resulted in lower serum concentrations of triacylglycerol (by 19.2 +/- 5.6%; P = 0.003), uric acid (by 12.7 +/- 2.0%; P < 0.001), and creatinine (by 2.5 +/- 1.1%; P = 0.035) and higher serum concentrations of urea (by 42.2 +/- 5.8%; P < 0.001) and a higher 24-h urinary urea output (by 99.2 +/- 17.2%; P < 0.001). No significant differences were detected in total or HDL cholesterol or in the renal clearance of creatinine. LDL oxidation, assessed as the ratio of conjugated dienes to LDL cholesterol in the LDL fraction, was lower with the high-protein diet (by 10.6 +/- 3.6%; P = 0.009).

CONCLUSIONS

High intakes of vegetable protein from gluten may have beneficial effects on cardiovascular disease risk by reducing oxidized LDL, serum triacylglycerol, and uric acid. Further studies are required to assess the longer-term effects on renal function.

Gluten challenge in borderline gluten-sensitive enteropathy

OBJECTIVES

In patients with signs and symptoms of malabsorption, suggestive of gluten-sensitive enteropathy, small intestinal biopsies sometimes only reveal infiltration of lymphocytes into the mucosal epithelium. This infiltrative lesion (Marsh I) is not a definite proof for gluten-sensitive enteropathy. However, in the present study, we aimed to show that a subgroup of these patients could ultimately be identified as being gluten sensitive.

METHODS

A total of 38 patients with a Marsh I lesion were subjected to a gluten challenge comprising 30 g of gluten added daily to a normal gluten-containing diet for 8 wk. Before and after the challenge, small intestinal biopsies were taken, and symptoms and signs of malabsorption were scored.

RESULTS

In 12 patients we demonstrated a significant change in mucosal histopathology, i.e., subtotal villous atrophy (Marsh IIIB, n = 1), partial villous atrophy (Marsh 3A, n = 6) or infiltrative-crypthyperplastic lesions (Marsh II, n = 5). In the other 26 patients, the small intestinal mucosa remained unchanged. After initiation of a gluten-free diet, follow-up small intestinal biopsies in 12 patients who initially had progressive mucosal pathology after gluten challenge showed normalization of mucosal pathology in seven cases, regression to a Marsh I lesion in four, and to a Marsh II lesion in one. Symptom relief was seen in all 12 patients. Ten of 26 patients without histological response to the gluten challenge were motivated to adhere to a gluten-free diet. Follow-up biopsies revealed unchanged Marsh I lesions in eight patients and normalization (Marsh 0) in two patients. Three patients had follow-up biopsies while on a normal diet. All had unchanged Marsh I lesions.

CONCLUSIONS

In the present study we demonstrated that a gluten challenge might be useful in identifying patients as being sensitive to gluten if initial small intestinal biopsies reveal only minor abnormalities.