Olfactory event-related potentials (OERPs) and trigeminal event-related potentials (TERPs) - a pilot study in Czech participants with normal sense of smell.

INTRODUCTION: In recent years, the evaluation of potential events related to olfactory events (OERPs) and trigeminal events (TERPs) has become increasingly important in the diagnosis of olfactory disorders. This technique is increasingly used in basic research and clinical practice to evaluate people suffering from olfactory disorders. PURPOSE OF THE STUDY: In a pilot project of the first investigations of OERPs and TERPs in the Czech Republic, we analyse the event-related potentials of the data of normosmic participants. METHODS: In the prospective study, 21 normosmic participants were enrolled for a 2-year period (5/2021-5/2023). OERPs/TERPs were recorded at the scalp vertex (electrode Pz/Cz). Odourants 2-phenylethanol/CO2 were used to selectively activate Nervus olfactorius/ Nervus trigeminus. Brain responses to olfactory/trigeminal stimuli (EEG) were recorded in 21/18 normosmic subjects. RESULTS: In the statistical analysis of the olfactory interval N1-P2 (age, gender), we found no statistically significant differences. In the statistical analysis of the trigeminal interval N1-P2 (age, gender) we found statistically significant differences in amplitude by gender (male amplitudes were higher than female amplitudes, p = 0.006). CONCLUSION: Our pilot data can function very well as an internal guide for ongoing and future olfactory research studies. Evaluation of the presence of OERPs appears to be an important parameter for the evaluation of olfactory disorders. The absence of OERPs is a strong indicator of the presence of olfactory dysfunction.

Reduced phosphatidylcholine level in the intestinal mucus layer of prediabetic NOD mice.

Type 1 diabetes (T1D) is an autoimmune disease with rising incidence. Pre- and manifest T1D is associated with intestinal barrier dysfunction, skewed microbiota composition, and serum dyslipidemia. The intestinal mucus layer protects against pathogens and its structure and phosphatidylcholine (PC) lipid composition may be compromised in T1D, potentially contributing to barrier dysfunction. This study compared prediabetic Non-Obese Diabetic (NOD) mice to healthy C57BL/6 mice by analyzing the intestinal mucus PC profile by shotgun lipidomics, plasma metabolomics by mass spectrometry and nuclear magnetic resonance, intestinal mucus production by histology, and cecal microbiota composition by 16 S rRNA sequencing. Jejunal mucus PC class levels were decreased in early prediabetic NOD vs C57BL/6 mice. In colonic mucus of NOD mice, the level of several PC species was reduced throughout prediabetes. In plasma, similar reductions of PC species were observed in early prediabetic NOD mice, where also increased beta-oxidation was prominent. No histological alterations were found in jejunal nor colonic mucus between the mouse strains. However, the ß-diversity of the cecal microbiota composition differed between prediabetic NOD and C57BL/6 mice, and the bacterial species driving this difference were related to decreased short-chain fatty acid (SCFA)-production in the NOD mice. This study reports reduced levels of PCs in the intestinal mucus layer and plasma of prediabetic NOD mice as well as reduced proportions of SCFA-producing bacteria in cecal content at early prediabetes, possibly contributing to intestinal barrier dysfunction and T1D.

Protective Effect of Vegan Microbiota on Liver Steatosis Is Conveyed by Dietary Fiber: Implications for Fecal Microbiota Transfer Therapy.

Fecal microbiota transfer may serve as a therapeutic tool for treating obesity and related disorders but currently, there is no consensus regarding the optimal donor characteristics. We studied how microbiota from vegan donors, who exhibit a low incidence of non-communicable diseases, impact on metabolic effects of an obesogenic diet and the potential role of dietary inulin in mediating these effects. Ex-germ-free animals were colonized with human vegan microbiota and fed a standard or Western-type diet (WD) with or without inulin supplementation. Despite the colonization with vegan microbiota, WD induced excessive weight gain, impaired glucose metabolism, insulin resistance, and liver steatosis. However, supplementation with inulin reversed steatosis and improved glucose homeostasis. In contrast, inulin did not affect WD-induced metabolic changes in non-humanized conventional mice. In vegan microbiota-colonized mice, inulin supplementation resulted in a significant change in gut microbiota composition and its metabolic performance, inducing the shift from proteolytic towards saccharolytic fermentation (decrease of sulfur-containing compounds, increase of SCFA). We found that (i) vegan microbiota alone does not protect against adverse effects of WD; and (ii) supplementation with inulin reversed steatosis and normalized glucose metabolism. This phenomenon is associated with the shift in microbiota composition and accentuation of saccharolytic fermentation at the expense of proteolytic fermentation.

Olfactory Evaluation in Clinical Medical Practice.

The subjective and demanding nature of olfactory testing means that it is often neglected in clinic despite loss of smell leading to significant limitations in everyday life. The list of diseases associated with loss of olfaction far exceeds the field of otorhinolaryngology and can also be seen in neurodegenerative disorders. Knowledge of possible clinical testing is essential to determine a proper differential diagnosis for the loss of olfactory sense. Causes of olfactory impairment can be divided into either failure in transferring odour to the organ of perception or damage to the olfactory pathway structure itself. Examination should therefore include methods evaluating cross-sectional area and patency of the nasal cavity as well as subjective or objective assessment of olfactory function. In this report we summarize several articles, studies, and our own experiences to provide a comprehensive review of their current clinical usage including their benefits, limitations, and possible outcomes. We also discuss the mechanism of olfaction step by step to provide a full understanding of the possible errors depending on the localization in the pathway and the methods designed for their detection. We discuss the correlation of the microbiome in nasal polyposis and chronic rhinitis with olfactory impairment using objective olfactometry. The topic of objective olfactometry and the examination of olfactory event-related potentials (OERP) is commented upon in detail.

Engineered human cytokine/antibody fusion proteins expand regulatory T cells and confer autoimmune disease protection.

Low-dose human interleukin-2 (hIL-2) treatment is used clinically to treat autoimmune disorders due to the cytokine's preferential expansion of immunosuppressive regulatory T cells (Tregs). However, off-target immune cell activation and short serum half-life limit the clinical potential of IL-2 treatment. Recent work showed that complexes comprising hIL-2 and the anti-hIL-2 antibody F5111 overcome these limitations by preferentially stimulating Tregs over immune effector cells. Although promising, therapeutic translation of this approach is complicated by the need to optimize dosing ratios and by the instability of the cytokine/antibody complex. We leverage structural insights to engineer a single-chain hIL-2/F5111 antibody fusion protein, termed F5111 immunocytokine (IC), which potently and selectively activates and expands Tregs. F5111 IC confers protection in mouse models of colitis and checkpoint inhibitor-induced diabetes mellitus. These results provide a roadmap for IC design and establish a Treg-biased immunotherapy that could be clinically translated for autoimmune disease treatment.

Local Angiotensin-Converting Enzyme 2 Gene Expression in Kidney Allografts Is Not Affected by Renin-Angiotensin-Aldosterone Inhibitors.

BACKGROUND: Preclinical studies suggested that pharmacological inhibition of the renin-angiotensin-aldosterone system (RAAS) by ACE inhibitors (ACEis) or angiotensin II receptor blockers (ARBs) may increase local angiotensin-converting enzyme 2 (ACE2) expression. METHODS: In this study, we evaluated the effect of ACEi or ARB treatment on expression of ACE2, ACE, and AGTR1 in 3-month protocol kidney allograft biopsies of stable patients using RT-qPCR (n = 48). Protein ACE2 expression was assessed using immunohistochemistry from paraffin sections. RESULTS: The therapy with RAAS blockers was not associated with increased ACE2, ACE, or ATGR1 expression in kidney allografts and also ACE2 protein immunohistochemistry did not reveal differences among groups. CONCLUSIONS: ACEis or ARBs in kidney transplant recipients do not affect local ACE2 expression. This observation supports long-term RAAS treatment in kidney transplant recipients, despite acute complications such as COVID-19 where ACE2 serves as the entry protein for infection.

Gluten-free diet in children with recent-onset type 1 diabetes: A 12-month intervention trial.

AIM: To test whether a gluten-free diet (GFD) is associated with the deceleration of the decline in beta-cell capacity in non-coeliac children with recently diagnosed type 1 diabetes. METHODS: Forty-five children (aged 10.2 ± 3.3 years) were recruited into a self-selected intervention trial: 26 started with a GFD within a median of 38 days postonset, whereas 19 remained on a standard diet. The main outcomes were the decline in C-peptide area under the curve (AUC) in mixed-meal tolerance tests (MMTTs) at 6 and 12 months relative to 1 month after diabetes onset and the difference in insulin dose, insulin dose-adjusted A1c (IDAA1c) and HbA1c assessed every 3 months. The adherence to the GFD was verified by immunoreactive gluten in the stool and by food questionnaires at every visit. Quality of life (QoL) questionnaires were administered to the participants at the end of the intervention at 12 months. The data were analysed as per protocol (in 39 subjects who duly completed the whole follow-up: 20 in the GFD group, 19 in the control group) by linear and longitudinal regression models adjusted for sex, age and baseline variables. RESULTS: At 12 months, the difference in C-peptide AUC between subjects in the GFD group and controls was 205 pmol/L (95% CI -223 to 633; P = 0.34) in a model adjusted for age, sex and body weight, and for baseline insulin dose, MMTT C-peptide AUC and HbA1c assessed at 1 month after diagnosis. In a longitudinal analysis of all three time points adjusted for age, sex and body weight, C-peptide declined more slowly in the GFD group than in controls, with the difference in trends being 409 pmol/L/year (P = 0.04). The GFD group had a marginally lower insulin dose (by 0.15 U/kg/day; P = 0.07), a lower IDAA1c (by 1.37; P = 0.01) and a lower mean HbA1c (by 0.7% [7.8 mmol/mol]; P = 0.02) than those of the controls at 12 months. There was no appreciable difference between the groups in daily carbohydrate intake (P = 0.49) or in the QoL reported by the patients (P = 0.70) and their parents/caregivers (P = 0.59). CONCLUSIONS: A GFD maintained over the first year after type 1 diabetes diagnosis was associated with better HbA1c and a prolonged partial remission period. There was a hint of slower C-peptide decline but the association was not strong enough to make definite conclusions.

Optimal Tolerogenic Dendritic Cells in Type 1 Diabetes (T1D) Therapy: What Can We Learn From Non-obese Diabetic (NOD) Mouse Models?

Tolerogenic dendritic cells (tolDCs) are explored as a promising standalone or combination therapy in type 1 diabetes (T1D). The therapeutic application of tolDCs, including in human trials, has been tested also in other autoimmune diseases, however, T1D displays some unique features. In addition, unlike in several disease-induced animal models of autoimmune diseases, the prevalent animal model for T1D, the NOD mouse, develops diabetes spontaneously. This review compares evidence of various tolDCs approaches obtained from animal (mainly NOD) models of T1D with a focus on parameters of this cell-based therapy such as protocols of tolDC preparation, antigen-specific vs. unspecific approaches, doses of tolDCs and/or autoantigens, application schemes, application routes, the migration of tolDCs as well as their preventive, early pre-onset intervention or curative effects. This review also discusses perspectives of tolDC therapy and areas of preclinical research that are in need of better clarification in animal models in a quest for effective and optimal tolDC therapies of T1D in humans.

Human gut microbiota transferred to germ-free NOD mice modulate the progression towards type 1 diabetes regardless of the pace of beta cell function loss in the donor.

AIMS/HYPOTHESIS: This study aimed to assess the ability of human gut microbiota to delay the onset of type 1 diabetes when transferred into germ-free NOD mice. METHODS: Two children with rapid and three children with slow beta cell function loss (as assessed by C-peptide AUC change in the mixed-meal tolerance tests performed 1 and 12 months after type 1 diabetes onset), participating in an ongoing trial with gluten-free diet, donated faeces, which were transferred into germ-free NOD mice. The mice were subsequently followed for diabetes incidence. RESULTS: The bacterial profiles of bacteriome-humanised mice had significantly (p < 10-5) lower alpha diversity than the donor material, with marked shifts in ratios between the main phyla. Diabetes onset was significantly delayed in all bacteriome-humanised colonies vs germ-free NOD mice, but the pace of beta cell loss was not transferable to the mouse model. CONCLUSIONS/INTERPRETATION: Germ-free NOD mice colonised with human gut microbiome are able to adopt a large proportion of transferred bacterial content, although the ratios of main phyla are reproduced only suboptimally. The recipient mice did not replicate the phenotype of the stool donor in relation to the pace towards type 1 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov NCT02867436.

Antigen Loading (e.g., Glutamic Acid Decarboxylase 65) of Tolerogenic DCs (tolDCs) Reduces Their Capacity to Prevent Diabetes in the Non-Obese Diabetes (NOD)-Severe Combined Immunodeficiency Model of Adoptive Cotransfer of Diabetes As Well As in NOD Mice.

Tolerogenic DCs (tolDCs) are being researched as a promising intervention strategy also in autoimmune diseases including type 1 diabetes (T1D). T1D is a T-cell-mediated, organ-specific disease with several well-defined and rather specific autoantigens, i.e., proinsulin, insulin, glutamic acid decarboxylase 65 (GAD65), that have been used in animal as well as human intervention trials in attempts to achieve a more efficient, specific immunotherapy. In this study, we have tested tolerogenic DCs for their effectiveness to prevent adoptive transfer of diabetes by diabetogenic splenocytes into non-obese diabetes (NOD)-severe combined immunodeficiency (NOD-SCID) recipients. While i.p. application of tolDCs prepared from bone marrow of prediabetic NOD mice by vitamin D2 and dexamethasone significantly reduced diabetes transfer into the NOD-SCID females, this effect was completely abolished when tolDCs were loaded with the mouse recombinant GAD65, but also with a control protein-ovalbumin (OVA). The effect was not dependent on the presence of serum in the tolDC culture. Similar results were observed in NOD mice. Removal of possible bystander antigen-presenting cells within the diabetogenic splenocytes by negative magnetic sorting of T cells did not alter this surprising effect. Tolerogenic DCs loaded with an immunodominant mouse GAD65 peptide also displayed diminished diabetes-preventive effect. Tolerogenic DCs were characterized by surface maturation markers (CD40, CD80, CD86, MHC II) and the lipopolysaccharide stability test. Data from alloreactive T cell proliferation and cytokine induction assays (IFN-γ) did not reveal the differences observed in the diabetes incidence. Migration of tolDCs, tolDCs-GAD65 and tolDCs-OVA to spleen, mesenteric- and pancreatic lymph nodes displayed similar, mucosal pattern with highest accumulation in pancreatic lymph nodes present up to 9 days after the i.p. APPLICATION: These data document that mechanisms by which tolDCs operate in vivo require much better understanding for improving efficacy of this promising cell therapy, especially in the presence of an antigen, e.g., GAD65.

Cell-based Tolerogenic Therapy, Experience from Animal Models of Multiple Sclerosis, Type 1 Diabetes and Rheumatoid Arthritis.

Cell-based tolerogenic therapy is a promising approach for the treatment of autoimmune diseases and transplant rejection. Regulatory T cells and tolerogenic dendritic cells have been particularly explored in the treatment of various autoimmune disorders in experimental models of disease. Although some of these cells have already been tested in a limited number of clinical trials, there is still a need for preclinical research on tolerogenic cells in animal models of autoimmunity. This review will focus on the relevance of data obtained from studies in experimental animal models for the use of tolerogenic cell-based therapy in humans. Also, perspectives for further improvement of tolerogenic cell preparation towards enhanced suppressive activity and stability of the cells will be discussed.

Tolerogenic Dendritic Cells from Poorly Compensated Type 1 Diabetes Patients Have Decreased Ability To Induce Stable Antigen-Specific T Cell Hyporesponsiveness and Generation of Suppressive Regulatory T Cells.

Tolerogenic dendritic cells (tolDCs) may offer an interesting intervention strategy to re-establish Ag-specific tolerance in autoimmune diseases, including type 1 diabetes (T1D). T1D results from selective destruction of insulin-producing ß cells leading to hyperglycemia that, in turn, specifically affects a patient's immune system. In this study, we prepared monocyte-derived tolDCs modulated by dexamethasone and vitamin D2 from 31 T1D patients with optimal glycemic control and 60 T1D patients with suboptimal glycemic control and assessed their tolerogenic properties in correlation with metabolic state of patients. tolDCs differentiated from both groups of patients acquired a regulatory phenotype and an anti-inflammatory profile. Interestingly, tolDCs from well-controlled patients expressed higher levels of inhibitory molecules IL-T3 and PD-L1. Additionally, glutamic acid decarboxylase (GAD)65-loaded tolDCs from well-controlled patients decreased significantly primary Th1/Th17 responses, induced stable GAD65-specific T cell hyporesponsiveness, and suppressed markedly control DC-induced GAD65-specific T cell activation compared with poorly controlled patients. The ability of tolDCs from poorly controlled patients to induce durable GAD65-specific T cell hyporesponsiveness was reversed once the control of glycemia improved. In both groups of patients, tolDCs were able to induce regulatory T cells from autologous naive CD4+ T cells. However, regulatory T cells from well-controlled patients had better suppressive abilities. The functionality of tolDCs was confirmed in the adoptive transfer model of NOD-SCID mice where tolDCs delayed diabetes onset. These results suggest that metabolic control of T1D affects the functional characteristics of tolDCs and subsequent effector T cell responses. Metabolic control may be relevant for refining inclusion criteria of clinical trials in the settings of T1D.

Gluten-Free Diet Only during Pregnancy Efficiently Prevents Diabetes in NOD Mouse Offspring.

Studies have documented that the pathogenesis of autoimmune diabetes is influenced by the intake of gluten. Aims. To investigate the importance of gluten exposure during pregnancy and the subsequent development of autoimmune diabetes in offspring. Methods. Nonobese diabetic mice were divided into 7 groups to receive combinations of gluten-free and standard diet before, during, or after pregnancy. Diabetes incidence in offspring was followed in each group (n = 16-27) for 310 days. Insulitis score and intestinal expression of T-cell transcription factors (RT-QPCR) were evaluated in animals from the different diet groups. Results. If mothers were fed a gluten-free diet only during pregnancy, the development of autoimmune diabetes in offspring was almost completely prevented with an incidence reduction from 62.5% in gluten-consuming mice to 8.3% (p < 0.0001) in the gluten-free group. The islets of Langerhans were less infiltrated (p < 0.001) and the intestinal expression of RORγt (Th17) (p < 0.0001) reduced in mice whose mothers were Gluten-free during pregnancy. Conclusion. A gluten-free diet exclusively during pregnancy efficiently prevents autoimmune diabetes development in offspring and reduces insulitis and intestinal expression of RORγt (Th17).

Dietary gluten and the development of type 1 diabetes.

Gluten proteins differ from other cereal proteins as they are partly resistant to enzymatic processing in the intestine, resulting in a continuous exposure of the proteins to the intestinal immune system. In addition to being a disease-initiating factor in coeliac disease (CD), gluten intake might affect type 1 diabetes development. Studies in animal models of type 1 diabetes have documented that the pathogenesis is influenced by diet. Thus, a gluten-free diet largely prevents diabetes in NOD mice while a cereal-based diet promotes diabetes development. In infants, amount, timing and mode of introduction have been shown to affect the diabetogenic potential of gluten, and some studies now suggest that a gluten-free diet may preserve beta cell function. Other studies have not found this effect. There is evidence that the intestinal immune system plays a primary role in the pathogenesis of type 1 diabetes, as diabetogenic T cells are initially primed in the gut, islet-infiltrating T cells express gut-associated homing receptors, and mesenteric lymphocytes transfer diabetes from NOD mice to NOD/severe combined immunodeficiency (SCID) mice. Thus, gluten may affect diabetes development by influencing proportional changes in immune cell populations or by modifying the cytokine/chemokine pattern towards an inflammatory profile. This supports an important role for gluten intake in the pathogenesis of type 1 diabetes and further studies should be initiated to clarify whether a gluten-free diet could prevent disease in susceptible individuals or be used with newly diagnosed patients to stop disease progression.

Prevention or early cure of type 1 diabetes by intranasal administration of gliadin in NOD mice.

Induction of long-term tolerance to ß-cell autoantigens has been investigated both in animal models and in human type 1 diabetes (T1D) in order to prevent the disease. As regards external compounds, the dietary plant protein fraction has been associated with high penetrance of the disease, whereas gluten-free diets prevent T1D in animal models. Herewith we investigated whether intranasal (i.n.) administration of gliadin or gluten may arrest the diabetogenic process. I.n. administration of gliadin to 4-week-old NOD mice significantly reduced the diabetes incidence. Similarly, the insulitis was lowered. Intranasal gliadin also rescued a fraction of prediabetic 13-week-old NOD mice from progressing to clinical onset of diabetes compared to OVA-treated controls. Vaccination with i.n. gliadin led to an induction of CD4(+)Foxp3(+) T cells and even more significant induction of γδ T cells in mucosal, but not in non-mucosal lymphoid compartments. This prevention strategy was characterized by an increased proportion of IL-10 and a decreased proportion of IL-2, IL-4 and IFN-γ-positive CD4(+)Foxp3(+) T cells, and IFN-γ-positive γδ T cells, preferentially in mucosal lymphoid organs. In conclusion, i.n. vaccination with gliadin, an environmental antigen with possible etiological influence in T1D, may represent a novel, safer strategy for prevention or even early cure of T1D.

Pepsin digest of wheat gliadin fraction increases production of IL-1ß via TLR4/MyD88/TRIF/MAPK/NF-κB signaling pathway and an NLRP3 inflammasome activation.

Celiac disease (CD) is a gluten-responsive, chronic inflammatory enteropathy. IL-1 cytokine family members IL-1ß and IL-18 have been associated with the inflammatory conditions in CD patients. However, the mechanisms of IL-1 molecule activation in CD have not yet been elucidated. We show in this study that peripheral blood mononuclear cells (PBMC) and monocytes from celiac patients responded to pepsin digest of wheat gliadin fraction (PDWGF) by a robust secretion of IL-1ß and IL-1α and a slightly elevated production of IL-18. The analysis of the upstream mechanisms underlying PDWGF-induced IL-1ß production in celiac PBMC show that PDWGF-induced de novo pro-IL-1ß synthesis, followed by a caspase-1 dependent processing and the secretion of mature IL-1ß. This was promoted by K+ efflux and oxidative stress, and was independent of P2X7 receptor signaling. The PDWGF-induced IL-1ß release was dependent on Nod-like receptor family containing pyrin domain 3 (NLRP3) and apoptosis-associated speck like protein (ASC) as shown by stimulation of bone marrow derived dendritic cells (BMDC) from NLRP3(-/-) and ASC(-/-) knockout mice. Moreover, treatment of human PBMC as well as MyD88(-/-) and Toll-interleukin-1 receptor domain-containing adaptor-inducing interferon-ß (TRIF)(-/-) BMDC illustrated that prior to the activation of caspase-1, the PDWGF-triggered signal constitutes the activation of the MyD88/TRIF/MAPK/NF-κB pathway. Moreover, our results indicate that the combined action of TLR2 and TLR4 may be required for optimal induction of IL-1ß in response to PDWGF. Thus, innate immune pathways, such as TLR2/4/MyD88/TRIF/MAPK/NF-κB and an NLRP3 inflammasome activation are involved in wheat proteins signaling and may play an important role in the pathogenesis of CD.

Dietary gluten alters the balance of pro-inflammatory and anti-inflammatory cytokines in T cells of BALB/c mice.

Several studies have documented that dietary modifications influence the development of type 1 diabetes. However, little is known about the interplay of dietary components and the penetration of diabetes incidence. In this study we tested if wheat gluten is able to induce differences in the cytokine pattern of Foxp3(+) regulatory T cells, as well as Foxp3(-) T cells, isolated from intestinal mucosal lymphoid tissue and non-mucosal lymphoid compartments in BALB/c mice. The gluten-containing standard diet markedly changed the cytokine expression within Foxp3(-) T cells, in all lymphoid organs tested, towards a higher expression of pro-inflammatory interferon-γ (IFN-γ), interleukin-17 (IL-17) and IL-2. In Foxp3(+) regulatory T cells, gluten ingestion resulted in a mucosal increase in IL-17 and IL-2 and an overall increase in IFN-γ and IL-4. The gluten-free diet induced an anti-inflammatory cytokine profile with higher proportion of transforming growth factor-ß (TGF-ß)(+) Foxp3(-) T cells in all tested lymphoid tissues and higher IL-10 expression within non-T cells in spleen, and a tendency towards a mucosal increase in TGF-ß(+) Foxp3(+) regulatory T cells. Our data shows that the gluten-containing standard diet modifies the cytokine pattern of both Foxp3(-) T cells and Foxp3(+) regulatory T cells towards a more inflammatory cytokine profile. This immune profile may contribute to the higher type 1 diabetes incidence associated with gluten intake.

Impact of dietary gluten on regulatory T cells and Th17 cells in BALB/c mice.

Dietary gluten influences the development of type 1 diabetes (T1D) and a gluten-free (GF) diet has a protective effect on the development of T1D. Gluten may influence T1D due to its direct effect on intestinal immunity; however, these mechanisms have not been adequately studied. We studied the effect of a GF diet compared to a gluten-containing standard (STD) diet on selected T cell subsets, associated with regulatory functions as well as proinflammatory Th17 cells, in BALB/c mice. Furthermore, we assessed diet-induced changes in the expression of various T cell markers, and determined if changes were confined to intestinal or non-intestinal lymphoid compartments. The gluten-containing STD diet led to a significantly decreased proportion of γδ T cells in all lymphoid compartments studied, although an increase was detected in some γδ T cell subsets (CD8(+), CD103(+)). Further, it decreased the proportion of CD4(+)CD62L(+) T cells in Peyer's patches. Interestingly, no diet-induced changes were found among CD4(+)Foxp3(+) T cells or CD3(+)CD49b(+)cells (NKT cells) and CD3(-)CD49b(+) (NK) cells. Mice fed the STD diet showed increased proportions of CD4(+)CD45RB(high+) and CD103(+) T cells and a lower proportion of CD4(+)CD45RB(low+) T cells in both mucosal and non-mucosal compartments. The Th17 cell population, associated with the development of autoimmunity, was substantially increased in pancreatic lymph nodes of mice fed the STD diet. Collectively, our data indicate that dietary gluten influences multiple regulatory T cell subsets as well as Th17 cells in mucosal lymphoid tissue while fewer differences were observed in non-mucosal lymphoid compartments.

The role of gut microbiota (commensal bacteria) and the mucosal barrier in the pathogenesis of inflammatory and autoimmune diseases and cancer: contribution of germ-free and gnotobiotic animal models of human diseases.

Metagenomic approaches are currently being used to decipher the genome of the microbiota (microbiome), and, in parallel, functional studies are being performed to analyze the effects of the microbiota on the host. Gnotobiological methods are an indispensable tool for studying the consequences of bacterial colonization. Animals used as models of human diseases can be maintained in sterile conditions (isolators used for germ-free rearing) and specifically colonized with defined microbes (including non-cultivable commensal bacteria). The effects of the germ-free state or the effects of colonization on disease initiation and maintenance can be observed in these models. Using this approach we demonstrated direct involvement of components of the microbiota in chronic intestinal inflammation and development of colonic neoplasia (i.e., using models of human inflammatory bowel disease and colorectal carcinoma). In contrast, a protective effect of microbiota colonization was demonstrated for the development of autoimmune diabetes in non-obese diabetic (NOD) mice. Interestingly, the development of atherosclerosis in germ-free apolipoprotein E (ApoE)-deficient mice fed by a standard low-cholesterol diet is accelerated compared with conventionally reared animals. Mucosal induction of tolerance to allergen Bet v1 was not influenced by the presence or absence of microbiota. Identification of components of the microbiota and elucidation of the molecular mechanisms of their action in inducing pathological changes or exerting beneficial, disease-protective activities could aid in our ability to influence the composition of the microbiota and to find bacterial strains and components (e.g., probiotics and prebiotics) whose administration may aid in disease prevention and treatment.