Remission without insulin therapy on gluten-free diet in a 6-year old boy with type 1 diabetes mellitus

Insights in Nutrition to Optimize Type 1 Diabetes Therapy

Nutrition is an essential part of therapy for type 1 diabetes and is constantly evolving, offering growing opportunities to prevent this disease, slow down its evolution, and mitigate it. An attempt was made to bring together the current state of knowledge. In the path from the preclinical phase of the disease to its clinical onset, there is a phase known as the "honeymoon period" or partial remission, where different possible dietary options for combatting this disease have been presented. The most commonly used dietary models were compared, and the most frequent co-existing pathologies, such as overweight, non-alcoholic fatty liver disease, dyslipidemia, celiac disease, and metabolic instability, were addressed from their nutritional and dietary perspectives to provide clinicians with an updated framework of knowledge and support researchers in further investigations into the topic. Finally, a glimpse into the possible interplay between nutrition and the gut microbiome, food security, and ultra-processed food is provided. It is hoped that clinicians treating people with type 1 diabetes will be provided with further opportunities for the daily management of their patients through personalized nutrition.

Cumulative incidence of type 1 diabetes in two cohorts of children with different national gluten recommendations in infancy

AIMS

Between 1985 and 1996, Sweden experienced an "epidemic" of celiac disease with a fourfold increase in incidence in young children. Timing and amount of gluten introduced during infancy have been thought to explain this "epidemic". We aimed to study whether the cumulative incidence of type 1 diabetes differs between children born during the "epidemic" compared to children born after.

METHODS

This is a national register study in Sweden comparing the cumulative incidence of type 1 diabetes in two birth cohorts of 240 844 children 0-17 years old born 1992-1993, during the "epidemic", and 179 530 children born 1997-1998, after the "epidemic". Children diagnosed with type 1 diabetes were identified using three national registers.

RESULTS

The cumulative incidence of type 1 diabetes by the age of 17 was statistically significantly higher in those born after the "epidemic" 0.77% than in those born during the "epidemic" 0.68% (p < 0.001).

CONCLUSION

The incidence of type 1 diabetes is higher in those born after the epidemic compared to those born during the epidemic, which does not support the hypothesis that gluten introduction increases the incidence of T1D. Changes in gluten introduction did not halt the increased incidence of type 1 diabetes in Sweden.

Unveiling the Link: A Comprehensive Narrative Review of the Relationship Between Type 1 Diabetes Mellitus and Celiac Disease

Type 1 diabetes mellitus (T1DM) is an autoimmune condition with a genetic predisposition. It has underlying autoimmune destruction of the pancreatic cells that produce insulin. It is often accompanied by other autoimmune conditions. This article focuses on celiac disease (CD), also an autoimmune disease. It is caused by gluten exposure. Both these conditions have genetic predisposing factors. Apart from the genetic background, aberrant small intestine immune response, inflammation, and different grades of enteropathy present in T1DM and CD are the same. With a mean frequency of 8%, the CD frequency of T1DM ranges from 3 to 16%. All T1DM patients should undergo serological testing for CD using antibodies to tissue transglutaminase at the time of T1DM onset. Individuals with T1DM and those accompanied by CD must follow a diet with no gluten. To outline the steps that can avert the development of these disorders and reduce the morbidity of the affected people, a complete understanding of the intricate pathophysiology of T1DM and its connection to CD has been undertaken in this review. The use of resources, such as PubMed and Google Scholar, has made this possible.

Microbiota-dependent proteolysis of gluten subverts diet-mediated protection against type 1 diabetes

Diet and commensals can affect the development of autoimmune diseases like type 1 diabetes (T1D). However, whether dietary interventions are microbe-mediated was unclear. We found that a diet based on hydrolyzed casein (HC) as a protein source protects non-obese diabetic (NOD) mice in conventional and germ-free (GF) conditions via improvement in the physiology of insulin-producing cells to reduce autoimmune activation. The addition of gluten (a cereal protein complex associated with celiac disease) facilitates autoimmunity dependent on microbial proteolysis of gluten: T1D develops in GF animals monocolonized with Enterococcus faecalis harboring secreted gluten-digesting proteases but not in mice colonized with protease deficient bacteria. Gluten digestion by E. faecalis generates T cell-activating peptides and promotes innate immunity by enhancing macrophage reactivity to lipopolysaccharide (LPS). Gnotobiotic NOD Toll4-negative mice monocolonized with E. faecalis on an HC + gluten diet are resistant to T1D. These findings provide insights into strategies to develop dietary interventions to help protect humans against autoimmunity.

Gluten-Free Diet in Co-Existent Celiac Disease and Type 1 Diabetes Mellitus: Is It Detrimental or Beneficial to Glycemic Control, Vascular Complications, and Quality of Life?

Celiac disease (CeD) is associated with type 1 diabetes mellitus (T1DM), and both have the same genetic background. Most patients with T1DM who develop CeD are either asymptomatic or have mild CeD-related gastrointestinal symptoms. Therefore, children affected by T1DM should undergo screening for asymptomatic CeD. The aim of this review is to highlight the influence of a gluten-free diet (GFD) on glycemic control, growth rate, microvascular complications, and quality of life in patients with T1DM and CeD. PubMed, Google Scholar, Web of Science, and Cochrane Central databases were searched. Reports reviewed were those published from 1969 to 2022 that focused on the interplay of T1DM and CeD and examined the effect of diet on glycemic control, growth rate, and quality of life. The most challenging aspect for a child with T1DM and CeD is that most GFD foods have a high glycemic index, while low glycemic index foods are recommended for T1DM. Interestingly, dietary therapy for CeD could improve the elevated HbA1c levels. Avoiding gluten added to a diabetic dietary regimen in T1DM patients might impose practical limitations and lead to important restrictions in the lifestyle of a young patient. Consequently, non-adherence to GFD in patients with T1DM and CeD is common. GFD in patients with T1DM and CeD seems to lower the incidence of micro- and macrovascular complications, but this requires further investigation. It seems that adherence to GFD in young patients with T1DM and CeD leads to regular growth and a stable body mass index without any negative effect on HbA1c or insulin requirements. Furthermore, the lipid profile and quality of life seem to have improved with the introduction of GFD.

Gluten-free diet can ameliorate the symptoms of non-celiac autoimmune diseases

CONTEXT

A gluten-free diet (GFD) is the recommended treatment for gluten-dependent disease. In addition, gluten withdrawal is popular and occasionally is suggested as a treatment for other autoimmune diseases (ADs).

OBJECTIVE

The current systematic review summarizes those entities and discusses the logic behind using a GFD in classical non-gluten-dependentADs.

DATA SOURCES

A search for medical articles in PubMed/MEDLINE, Web of Sciences, LILACS, and Scielo published between 1960 and 2020 was conducted, using the key words for various ADs and GFDs.

DATA EXXTRACTION

Eight-three articles were included in the systematic review (using PRISMA guidelines).

DATA ANALYSIS

Reduction in symptoms of ADs after observance of a GFD was observed in 911 out of 1408 patients (64.7%) and in 66 out of the 83 selected studies (79.5%). The age of the patients ranged from 9 months to 69 years. The duration of the GFD varied from 1 month to 9 years. A GFD can suppress several harmful intraluminal intestinal events. Potential mechanisms and pathways for the action of GFD in the gut - remote organs' axis have been suggested.

CONCLUSION

A GFD might represent a novel nutritional therapeutic strategy for classical non-gluten-dependent autoimmune conditions.

Gluten Free Diet for the Management of Non Celiac Diseases: The Two Sides of the Coin

A lifelong adherence to a gluten-free (GF) diet is currently the only treatment for Celiac disease (CD), an autoimmune disorder that arises after gluten ingestion in individuals who are genetically predisposed. The gluten intake exerts toxic effects through several pathways involving gut barrier integrity, intestinal microbiota composition and immune system stimulation. However, despite the great benefit of GF diet for CD patients, its use has been debated. Indeed, individuals who adopt this diet regime may be at risk of nutrient deficiencies. Emerging evidence supports a beneficial effect of a GF diet also for other pathological conditions, including gluten-related disorders (GRD) often associated to CD, such as Non celiac gluten sensitivity (NCGS) and Dermatitis Herpetiforme (DH) as well as Irritable bowel syndrome (IBS) and Diabetes. This suggests a pathogenic role of gluten in these conditions. Despite the growing popularity of GF diet among consumers, to date, there are limited evidences supporting its use for the management of non-celiac diseases. Therefore, in this review, we discuss whether the GF diet could really improve the general quality of life of patients with GRD and non-GRD conditions, keeping in mind its sensorial limitations and nutritional inadequacies. In addition, we discuss the current motivations, leading to the use of a GF diet, despite the inferior quality of GF products respect to those containing gluten.

Current Evidence on the Efficacy of Gluten-Free Diets in Multiple Sclerosis, Psoriasis, Type 1 Diabetes and Autoimmune Thyroid Diseases

In this review, we summarize the clinical data addressing a potential role for gluten in multiple sclerosis (MS), psoriasis, type 1 diabetes (T1D) and autoimmune thyroid diseases (ATDs). Furthermore, data on the prevalence of celiac disease (CD) and gluten-related antibodies in the above patient groups are presented. Adequately powered and properly controlled intervention trials investigating the effects of a gluten-free diet (GFD) in non-celiac patients with MS, psoriasis, T1D or ATDs are lacking. Only one clinical trial has studied the effects of a GFD among patients with MS. The trial found significant results, but it is subject to major methodological limitations. A few publications have found beneficial effects of a GFD in a subgroup of patients with psoriasis that were seropositive for anti-gliadin or deamidated gliadin antibodies, but no effects were seen among seronegative patients. Studies on the role of gluten in T1D are contradictive, however, it seems likely that a GFD may contribute to normalizing metabolic control without affecting levels of islet autoantibodies. Lastly, the effects of a GFD in non-celiac patients with ATDs have not been studied yet, but some publications report that thyroid-related antibodies respond to a GFD in patients with concomitant CD and ATDs. Overall, there is currently not enough evidence to recommend a GFD to non-celiac patients with MS, psoriasis, ATDs or T1D.

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.

The Role of Gut Microbiota and Environmental Factors in Type 1 Diabetes Pathogenesis

Type 1 Diabetes (T1D) is regarded as an autoimmune disease characterized by insulin deficiency resulting from destruction of pancreatic β-cells. The incidence rates of T1D have increased worldwide. Over the past decades, progress has been made in understanding the complexity of the immune response and its role in T1D pathogenesis, however, the trigger of T1D autoimmunity remains unclear. The increasing incidence rates, immigrant studies, and twin studies suggest that environmental factors play an important role and the trigger cannot simply be explained by genetic predisposition. Several research initiatives have identified environmental factors that potentially contribute to the onset of T1D autoimmunity and the progression of disease in children/young adults. More recently, the interplay between gut microbiota and the immune system has been implicated as an important factor in T1D pathogenesis. Although results often vary between studies, broad compositional and diversity patterns have emerged from both longitudinal and cross-sectional human studies. T1D patients have a less diverse gut microbiota, an increased prevalence of Bacteriodetes taxa and an aberrant metabolomic profile compared to healthy controls. In this comprehensive review, we present the data obtained from both animal and human studies focusing on the large longitudinal human studies. These studies are particularly valuable in elucidating the environmental factors that lead to aberrant gut microbiota composition and potentially contribute to T1D. We also discuss how environmental factors, such as birth mode, diet, and antibiotic use modulate gut microbiota and how this potentially contributes to T1D. In the final section, we focus on existing recent literature on microbiota-produced metabolites, proteins, and gut virome function as potential protectants or triggers of T1D onset. Overall, current results indicate that higher levels of diversity along with the presence of beneficial microbes and the resulting microbial-produced metabolites can act as protectors against T1D onset. However, the specifics of the interplay between host and microbes are yet to be discovered.

Role of Dietary Gluten in Development of Celiac Disease and Type I Diabetes: Management Beyond Gluten-Free Diet

Gluten triggers Celiac Disease (CD) and type I diabetes in genetically predisposed population of human leukocyte antigen DQ2/DQ8+ and associates with disorders such as schizophrenia and autism. Application of a strict gluten-free diet is the only well-established treatment for patients with CD, whereas the treatment for patients with celiac type I diabetes may be depend on the timing and frequency of the diet. The application of a gluten-free diet in patients with CD may contribute to the development of metabolic syndrome and nonalcoholic fatty liver disease and may also lead to a high glycemic index, low fiber diet and micronutrient deficiencies. The alteration of copper bioavailability (deficient, excess or aberrant coordination) may contribute to the onset and progress of related pathologies. Therefore, nutrient intake of patients on a gluten-free diet should be the focus of future researches. Other gluten-based therapies have been rising with interest such as enzymatic pretreatment of gluten, oral enzyme supplements to digest dietary gluten, gluten removal by breeding wheat varieties with reduced or deleted gluten toxicity, the development of polymeric binders to suppress gluten induced pathology.

Type 1 diabetes and hyperthyroidism in a family with celiac disease after exposure to gluten: a rare case report

Background

Celiac disease (CD) is an autoimmune disorder related to the gluten and can be also associated with some other endocrine disorders such as type 1 diabetes and thyroid disease. Gluten exposure in CD may have especial role in developing other auto immune disorder.

Case presentation

We reported two familial cases with celiac disease who were on a gluten free diet (GFD) and hyperthyroidism and type 1 diabetes were appeared following a regular diet. Their autoimmune disorders were ameliorated after avoidance of dietary gluten.

Conclusions

These cases highlighted the role of gluten exposure in developing other autoimmune disorders associated with CD, especially in young patients whom they are not cooperative to keep GFD. We recommended to evaluate the organ specific antibodies for risk assessment in these patients.

Possible Prevention of Diabetes with a Gluten-Free Diet

Gluten seems a potentially important determinant in type 1 diabetes (T1D) and type 2 diabetes (T2D). Intake of gluten, a major component of wheat, rye, and barley, affects the microbiota and increases the intestinal permeability. Moreover, studies have demonstrated that gluten peptides, after crossing the intestinal barrier, lead to a more inflammatory milieu. Gluten peptides enter the pancreas where they affect the morphology and might induce beta-cell stress by enhancing glucose- and palmitate-stimulated insulin secretion. Interestingly, animal studies and a human study have demonstrated that a gluten-free (GF) diet during pregnancy reduces the risk of T1D. Evidence regarding the role of a GF diet in T2D is less clear. Some studies have linked intake of a GF diet to reduced obesity and T2D and suggested a role in reducing leptin- and insulin-resistance and increasing beta-cell volume. The current knowledge indicates that gluten, among many environmental factors, may be an aetiopathogenic factors for development of T1D and T2D. However, human intervention trials are needed to confirm this and the proposed mechanisms.

Association between maternal gluten intake and type 1 diabetes in offspring: national prospective cohort study in Denmark

OBJECTIVE

To examine the association between prenatal gluten exposure and offspring risk of type 1 diabetes in humans.

DESIGN

National prospective cohort study.

SETTING

National health information registries in Denmark.

PARTICIPANTS

Pregnant Danish women enrolled into the Danish National Birth Cohort, between January 1996 and October 2002, MAIN OUTCOME MEASURES: Maternal gluten intake, based on maternal consumption of gluten containing foods, was reported in a 360 item food frequency questionnaire at week 25 of pregnancy. Information on type 1 diabetes occurrence in the participants' children, from 1 January 1996 to 31 May 2016, were obtained through registry linkage to the Danish Registry of Childhood and Adolescent Diabetes.

RESULTS

The study comprised 101 042 pregnancies in 91 745 women, of whom 70 188 filled out the food frequency questionnaire. After correcting for multiple pregnancies, pregnancies ending in abortions, stillbirths, lack of information regarding the pregnancy, and pregnancies with implausibly high or low energy intake, 67 565 pregnancies (63 529 women) were included. The average gluten intake was 13.0 g/day, ranging from less than 7 g/day to more than 20 g/day. The incidence of type 1 diabetes among children in the cohort was 0.37% (n=247) with a mean follow-up period of 15.6 years (standard deviation 1.4). Risk of type 1 diabetes in offspring increased proportionally with maternal gluten intake during pregnancy (adjusted hazard ratio 1.31 (95% confidence interval 1.001 to 1.72) per 10 g/day increase of gluten). Women with the highest gluten intake versus those with the lowest gluten intake (≥20 v <7 g/day) had double the risk of type 1 diabetes development in their offspring (adjusted hazard ratio 2.00 (95% confidence interval 1.02 to 4.00)).

CONCLUSIONS

High gluten intake by mothers during pregnancy could increase the risk of their children developing type 1 diabetes. However, confirmation of these findings are warranted, preferably in an intervention setting.

Effect of Early-life Gut Mucosal Compromise on Disease Progression in NOD Mice

Disease expression in spontaneous nonobese diabetic (NOD) mice depends on environmental stimuli such as stress, diet, and gut microbiota composition. We evaluated a brief, early-life gut intervention in which pups were weaned to low-dose dextran sulfate sodium (DSS). We hypothesized that the mucus-reducing effect of this compound and subsequent increased host-bacterial contact would delay disease onset and decrease insulitis due to enhanced oral tolerance. However, disease incidence did not differ between groups, although median survival (time point when 50% of the mice are still alive) of the control group was 184 d compared with 205 d for DSS-treated mice. Mean age at disease onset (that is, blood glucose of at least 12 mmol/L) was 164 d for control mice and 159 d for DSS-treated mice. In addition, 62.5% of control mice reached a blood glucose of 12 mmol/L before 30 wk of age compared with 59% in DSS-treated mice, which had a significant transient increase in serum insulin in week 4. No changes were found in immune cells collected from spleen, pancreatic lymph nodes, and mesenteric lymph nodes. Although mice received a low dose of DSS, the subsequent reduction in the diversity of the microbiota during weeks 4 through 6 led to increased cecal length and weight and, in week 13, a tendency toward decreased colon length, with increased leakage of LPS to the blood. We conclude that mucus reduction and subsequent increased host-bacterial contact did not affect overall disease progression in NOD mice.

Occupation with grain crops is associated with lower type 1 diabetes incidence: Registry-based case-control study

Intranasal administration of gliadin prevents autoimmune diabetes in non-obese diabetic mice. The current study was designed to investigate if bakers are intranasally exposed to gluten during work and whether occupation as baker is inversely associated with type 1 diabetes. Gliadin was measured in nasal swabs from eight bakers and butchers. The odds ratio of type 1 diabetes in selected profession groups was analysed in a registry-based case-control study with data from 1980 to 2010 derived from Statistics Denmark. The cohort included 1,210,017 Danish individuals, thereof 15,451 with type 1 diabetes (1.28%). Average nasal gliadin swab content after full working days was 6.3 μg (confidence interval (CI): 2.8 to 9.7) among bakers, while no nasal gliadin was detected among butchers. The odds ratio of type 1 diabetes was lower among bakers (OR = 0.57; CI: 0.52 to 0.62) and agriculture workers occupied with production of grains (OR = 0.65; CI: 0.56 to 0.75). Bakers had a lower odds ratio of type 1 diabetes, which potentially could be attributed to exposure of nasal mucosal gluten during work, as observed in this study. If other studies confirm the present observations, intranasal gliadin administration could possibly be an easy and safe approach for the prevention of type 1 diabetes in high-risk individuals or prediabetic subjects.

On the pathogenesis of insulin-dependent diabetes mellitus: the role of microbiota

Type 1 diabetes (T1D) is an autoimmune disorder characterized by the selective destruction of insulin-producing β cells as result of a complex interplay between genetic, stochastic and environmental factors in genetically susceptible individuals. An increasing amount of experimental data from animal models and humans has supported the role played by imbalanced gut microbiome in T1D pathogenesis. The commensal intestinal microbiota is fundamental for several physiologic mechanisms, including the establishment of immune homeostasis. Alterations in its composition have been correlated to changes in the gut immune system, including defective tolerance to food antigens, intestinal inflammation and enhanced gut permeability. Early findings reported differences in the intestinal microbiome of subjects affected by prediabetes or overt disease compared to healthy individuals. The present review focuses on microbiota-host homeostasis, its alterations, factors that influence microbiome composition and discusses their putative correlation with T1D development. Further studies are necessary to clarify the role played by microbiota modifications in the processes that cause enhanced permeability and the autoimmune mechanisms responsible for T1D onset.

Where genes meet environment-integrating the role of gut luminal contents, immunity and pancreas in type 1 diabetes

The rise in new cases of type 1 diabetes (T1D) in genetically susceptible individuals over the past half century has been attributed to numerous environmental "triggers" or promoters such as enteroviruses, diet, and most recently, gut bacteria. No single cause has been identified in humans, likely because there are several pathways by which one can develop T1D. There is renewed attention to the role of the gut and its immune system in T1D pathogenesis based largely on recent animal studies demonstrating that altering the gut microbiota affects diabetes incidence. Although T1D patients display dysbiosis in the gut microbiome, it is unclear whether this is cause or effect. The heart of this question involves several moving parts including numerous risk genes, diet, viruses, gut microbiota, timing, and loss of immune tolerance to β-cells. Most clinical trials have addressed only one aspect of this puzzle using some form of immune suppression, without much success. The key location where our genes meet and deal with the environment is the gastrointestinal tract. The influence of all of its major contents, including microbes, diet, and immune system, must be understood as part of the integrative biology of T1D before we can develop durable means of preventing, treating, or curing this disease. In the present review, we expand our previous gut-centric model based on recent developments in the field.

Endocrine manifestations in celiac disease

Celiac disease (CD) is an autoimmune small intestinal mucosal disorder that often presents with diarrhea, malabsorption and weight loss. Often, one or more associated endocrine disorders may be associated with CD. For this review, methods involved an extensive review of published English-language materials. In children and adolescents, prospective studies have demonstrated a significant relationship to insulin-dependent or type 1 diabetes, whereas in adults, autoimmune forms of thyroid disease, particularly hypothyroidism, may commonly co-exist. In some with CD, multiple glandular endocrinopathies may also occur and complicate the initial presentation of the intestinal disease. In others presenting with an apparent isolated endocrine disorder, serological screening for underlying subclinical CD may prove to be positive, particularly if type 1 diabetes, autoimmune thyroid or other autoimmune endocrine diseases, such as Addison’s disease are first detected. A number of reports have also recorded hypoparathyroidism or hypopituitarism or ovarian failure in CD and these may be improved with a strict gluten-free diet.

Gluten-free diet increases beta-cell volume and improves glucose tolerance in an animal model of type 2 diabetes

BACKGROUND

Gluten-free (GF) diet alleviates type 1 diabetes in animal models and possibly in humans. We recently showed that fatty acid-induced insulin secretion is enhanced by enzymatically digested gluten (gliadin) stimulation in INS-1E insulinoma cells. We therefore hypothesized that GF diet would induce beta-cell rest and ameliorate type 2 diabetes.

METHODS

C57BL/6JBomTac (B6) mice were fed a high-fat (HF), gluten-free high-fat (GF-HF), standard (STD) or gluten-free (GF) diet for 42 weeks.

RESULTS

Short-term (6-24 weeks) GF-HF versus HF feeding impaired glucose tolerance and increased fasting glucose. Long-term (36-42 weeks) GF-HF versus HF feeding improved glucose tolerance and decreased fasting leptin. Mice fed a GF-HF versus HF diet for 42 weeks showed higher volumes of beta cells, islets and pancreas. The beta-cell volume correlated with the islet- and pancreas volume as well as body weight. GF-HF versus HF diet did not influence toll-like receptor 4 (Tlr4), interleukin 1 (IL-1), interleukin 6 (IL-6) or tumour necrosis factor-alpha (TNF-alpha) mRNA expression in intestine. STD versus GF feeding did not affect any parameter studied.

CONCLUSIONS

Long-term feeding with GF-HF versus HF increases beta-cell volume and improves glucose tolerance in B6 mice. The mechanism may include beta-cell rest, but is unlikely to include TLR4 and proinflammatory cytokines in the intestine. Beta-cell volume correlates with pancreas volume and body weight, indicating that insulin secretion capacity controls pancreas volume. Thus, long-term GF diets may be beneficial for obese type 2 diabetes patients and trials should be performed. Copyright © 2016 John Wiley & Sons, Ltd.

Potential beneficial effects of a gluten-free diet in newly diagnosed children with type 1 diabetes: a pilot study

AIM

Gluten-free diet has shown promising effects in preventing type 1 diabetes (T1D) in animals as well as beneficial effects on the immune system. Gluten-free diet at diabetes onset may alter the natural course and outcome of autoimmune diseases such as T1D.

METHODS

In a 12-month study, 15 children newly diagnosed with T1D were instructed to follow a gluten-free diet. Questionnaires were used to evaluate adherence to the gluten-free diet. Partial remission (PR) was defined by insulin dose-adjusted A1c (IDAA1c) ≤9 or stimulated C-peptide (SCP) >300 pmol/L measured 90 min after a liquid mixed meal at the inclusion, six and 12 months after onset. The intervention group was compared with two previous cohorts. Linear mixed models were used to estimate differences between cohorts.

RESULTS

After 6 months, more children on a gluten-free diet tended to have SCP values above 300 pmol/L compared to the European cohort (p = 0.08). The adherence to a gluten-free diet decreased during the 12-month study period. After 1 year there was no difference in SCP levels or percentage in remission according to SCP (p > 0.1). Three times as many children were still in PR based on IDAA1c (p < 0.05). Twelve months after onset HbA1c were 21 % lower and IDAA1c >1 unit lower in the cohort on a gluten-free diet compared to the two previous cohorts (p < 0.001).

CONCLUSION

Gluten-free diet is feasible in highly motivated families and is associated with a significantly better outcome as assessed by HbA1c and IDAA1c. This finding needs confirmation in a randomized trial including screening for quality of life. (Clinicaltrials.gov number NCT02284815).

Where, How, and When: Positioning Posttranslational Modification Within Type 1 Diabetes Pathogenesis

Autoreactive T cells specific for islet autoantigens develop in type 1 diabetes (T1D) by escaping central as well as peripheral tolerance. The current paradigm for development of islet autoimmunity is just beginning to include the contribution of posttranslationally modified (PTM) islet autoantigens, for which the immune system may be ignorant rather than tolerant. As a result, PTM is the latest promising lead in the quest to understand how the break in peripheral tolerance occurs in T1D. However, it is not completely clear how, where, or when these modifications take place. Currently, only a few PTM antigens have been well-thought-out or identified in T1D, and methods for identifying and characterizing new PTM antigens are rapidly improving. This review will address both reported and potential new sources of modified islet autoantigens and discuss how islet neo-autoantigen generation may contribute to the development and progression of T1D.

Modulating the Gut Microbiota Improves Glucose Tolerance, Lipoprotein Profile and Atherosclerotic Plaque Development in ApoE-Deficient Mice

The importance of the gut microbiota (GM) in disease development has recently received increased attention, and numerous approaches have been made to better understand this important interplay. For example, metabolites derived from the GM have been shown to promote atherosclerosis, the underlying cause of cardiovascular disease (CVD), and to increase CVD risk factors. Popular interest in the role of the intestine in a variety of disease states has now resulted in a significant proportion of individuals without coeliac disease switching to gluten-free diets. The effect of gluten-free diets on atherosclerosis and cardiovascular risk factors is largely unknown. We therefore investigated the effect of a gluten-free high-fat cholesterol-rich diet, as compared to the same diet in which the gluten peptide gliadin had been added back, on atherosclerosis and several cardiovascular risk factors in apolipoprotein E-deficient (Apoe-/-) mice. The gluten-free diet transiently altered GM composition in these mice, as compared to the gliadin-supplemented diet, but did not alter body weights, glucose tolerance, insulin levels, plasma lipids, or atherosclerosis. In parallel, other Apoe-/- mice fed the same diets were treated with ampicillin, a broad-spectrum antibiotic known to affect GM composition. Ampicillin-treatment had a marked and sustained effect on GM composition, as expected. Furthermore, although ampicillin-treated mice were slightly heavier than controls, ampicillin-treatment transiently improved glucose tolerance both in the absence or presence of gliadin, reduced plasma LDL and VLDL cholesterol levels, and reduced aortic atherosclerotic lesion area. These results demonstrate that a gluten-free diet does not seem to have beneficial effects on atherosclerosis or several CVD risk factors in this mouse model, but that sustained alteration of GM composition with a broad-spectrum antibiotic has beneficial effects on CVD risk factors and atherosclerosis. These findings support the concept that altering the microbiota might provide novel treatment strategies for CVD.

Large Gliadin Peptides Detected in the Pancreas of NOD and Healthy Mice following Oral Administration

Gluten promotes type 1 diabetes in nonobese diabetic (NOD) mice and likely also in humans. In NOD mice and in non-diabetes-prone mice, it induces inflammation in the pancreatic lymph nodes, suggesting that gluten can initiate inflammation locally. Further, gliadin fragments stimulate insulin secretion from beta cells directly. We hypothesized that gluten fragments may cross the intestinal barrier to be distributed to organs other than the gut. If present in pancreas, gliadin could interact directly with the immune system and the beta cells to initiate diabetes development. We orally and intravenously administered 33-mer and 19-mer gliadin peptide to NOD, BALB/c, and C57BL/6 mice and found that the peptides readily crossed the intestinal barrier in all strains. Several degradation products were found in the pancreas by mass spectroscopy. Notably, the exocrine pancreas incorporated large amounts of radioactive label shortly after administration of the peptides. The study demonstrates that, even in normal animals, large gliadin fragments can reach the pancreas. If applicable to humans, the increased gut permeability in prediabetes and type 1 diabetes patients could expose beta cells directly to gliadin fragments. Here they could initiate inflammation and induce beta cell stress and thus contribute to the development of type 1 diabetes.

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).

The Role of Gluten in Celiac Disease and Type 1 Diabetes

Celiac disease (CD) and type 1 diabetes (T1D) are autoimmune conditions in which dietary gluten has been proven or suggested to play a pathogenic role. In CD; gluten is established as the instigator of autoimmunity; the autoimmune process is halted by removing gluten from the diet; which allows for resolution of celiac autoimmune enteropathy and subsequent normalization of serological markers of the disease. However; an analogous causative agent has not yet been identified for T1D. Nevertheless; the role of dietary gluten in development of T1D and the potentially beneficial effect of removing gluten from the diet of patients with T1D are still debated. In this review; we discuss the comorbid occurrence of CD and T1D and explore current evidences for the specific role of gluten in both conditions; specifically focusing on current evidence on the effect of gluten on the immune system and the gut microbiota.

Effect of dietary gluten on dendritic cells and innate immune subsets in BALB/c and NOD mice

The innate immune system is known to play an important role in oral tolerance to dietary antigens. This is important in development of celiac disease (CD) but may also be important in type 1 diabetes (T1D), and could potentially explain the reduced incidence of T1D in mice receiving a gluten-free (GF) diet. The direct in vivo effect of gluten on innate cells, and particularly dendritic cells (DC) is not sufficiently clarified. Therefore, we wished to investigate the innate cell populations of spontaneous diabetic NOD mice and healthy BALB/c mice kept on a GF or a standard (STD) gluten containing diet. We studied, by flow cytometry and reverse transcription-quantitative polymerase chain reaction (qRT-PCR), if dietary gluten induces changes in the activation of DCs and distribution of selected innate cells in lymphoid, pancreatic and intestinal tissues in BALB/c and NOD mice. We found that a GF diet increased the percentage of macrophages in BALB/c spleen and of CD11c⁺ DCs in BALB/c and NOD spleen. Strictly gluten-free (SGF) diet increased the percentage of CD103⁺ DCs in BALB/c mice and decreased percentages of CD11b⁺ DCs in mesenteric and pancreatic lymph nodes in BALB/c mice. SGF diet in BALB/c mice also decreased DC expression of CD40, CCR7 and MHC-II in pancreatic lymph nodes. In conclusion, GF diet changes the composition of the innate immune system in BALB/c and NOD mice and increases expression of DC activation markers in NOD mice. These results contribute to the explanation of the low diabetes incidence in GF NOD mice. This mechanism may be important in development of type 1 diabetes, celiac disease and non-celiac gluten sensitivity.

Nutrigenetics and nutrigenomics insights into diabetes etiopathogenesis

Diabetes mellitus (DM) is considered a global pandemic, and the incidence of DM continues to grow worldwide. Nutrients and dietary patterns are central issues in the prevention, development and treatment of this disease. The pathogenesis of DM is not completely understood, but nutrient-gene interactions at different levels, genetic predisposition and dietary factors appear to be involved. Nutritional genomics studies generally focus on dietary patterns according to genetic variations, the role of gene-nutrient interactions, gene-diet-phenotype interactions and epigenetic modifications caused by nutrients; these studies will facilitate an understanding of the early molecular events that occur in DM and will contribute to the identification of better biomarkers and diagnostics tools. In particular, this approach will help to develop tailored diets that maximize the use of nutrients and other functional ingredients present in food, which will aid in the prevention and delay of DM and its complications. This review discusses the current state of nutrigenetics, nutrigenomics and epigenomics research on DM. Here, we provide an overview of the role of gene variants and nutrient interactions, the importance of nutrients and dietary patterns on gene expression, how epigenetic changes and micro RNAs (miRNAs) can alter cellular signaling in response to nutrients and the dietary interventions that may help to prevent the onset of DM.

A gluten-free diet lowers NKG2D and ligand expression in BALB/c and non-obese diabetic (NOD) mice

The interplay between diet and immune parameters which could affect type 1 diabetes (T1D) pathogenesis is not sufficiently clarified. Intestinal up-regulation of the activating receptor natural killer group 2D (NKG2D) (CD314) and its ligands is a hallmark of coeliac disease. However, the direct effect of gluten on NKG2D expression is not known. We studied, by fluorescence activated cell sorter (lymphoid tissues) and reverse transcription–quantitative polymerase chain reaction (intestine and pancreatic islets), if a gluten-free diet (GF diet) from 4 weeks of age or a gluten-free diet introduced in breeding pairs (SGF diet), induced changes in NKG2D expression on DX5⁺(CD49b) natural killer (NK) cells, CD8⁺ T cells and in intestinal and islet levels of NKG2D and ligands in BALB/c and non-obese diabetic (NOD) mice. Gluten-free NOD mice had lower insulitis (P < 0·0001); reduced expression of NKG2D on DX5⁺ NK cells in spleen and auricular lymph nodes (P < 0·05); and on CD8⁺ T cells in pancreas-associated lymph nodes (P = 0·04). Moreover, the level of CD71 on DX5⁺ NK cells and CD8⁺ T cells (P < 0·005) was markedly reduced. GF and SGF mice had reduced expression of NKG2D and DX5 mRNA in intestine (P < 0·05). Differences in intestinal mRNA expression were found in mice at 8, 13 and 20 weeks. Intestinal expression of NKG2D ligands was reduced in SGF mice with lower expression of all ligands. In isolated islets, a SGF diet induced a higher expression of specific NKG2D ligands. Our data show that a gluten-free diet reduces the level of NKG2D and the expression of NKG2D ligands. These immunological changes may contribute to the lower T1D incidence associated with a gluten-free diet.

Dietary gluten increases natural killer cell cytotoxicity and cytokine secretion

Dietary gluten influences the development of type 1 diabetes in nonobese diabetic (NOD) mice and biobreeding rats, and has been shown to influence a wide range of immunological factors in the pancreas and gut. In the present study, the effects of gluten on NK cells were studied in vitro and in vivo. We demonstrated that gliadin increased direct cytotoxicity and IFN-γ secretion from murine splenocytes and NK cells toward the pancreatic beta-cell line MIN6 cells. Additionally, stimulation of MIN6 cells led to a significantly increased proportion of degranulating C57BL/6 CD107a(+) NK cells. Stimulation of C57BL/6 pancreatic islets with gliadin significantly increased secretion of IL-6 more than ninefold. In vivo, the gluten-containing diet led to a higher expression of NKG2D and CD71 on NKp46(+) cells in all lymphoid organs in BALB/c and NOD mice compared with the gluten-free diet. Collectively, our data suggest that dietary gluten increases murine NK-cell activity against pancreatic beta cells. This mechanism may contribute to development of type 1 diabetes and explain the higher disease incidence associated with gluten intake in NOD mice.

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.

Beyond genetics. Influence of dietary factors and gut microbiota on type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease ultimately leading to destruction of insulin secreting β-cells in the pancreas. Genetic susceptibility plays an important role in T1D etiology, but even mono-zygotic twins only have a concordance rate of around 50%, underlining that other factors than purely genetic are involved in disease development. Here we review the influence of dietary and environmental factors on T1D development in humans as well as animal models. Even though data are still inconclusive, there are strong indications that gut microbiota dysbiosis plays an important role in T1D development and evidence from animal models suggests that gut microbiota manipulation might prove valuable in future prevention of T1D in genetically susceptible individuals.

Clinical implications of shared genetics and pathogenesis in autoimmune diseases

Many endocrine diseases, including type 1 diabetes mellitus, Graves disease, Addison disease and Hashimoto disease, originate as an autoimmune reaction that affects disease-specific target organs. These autoimmune diseases are characterized by the development of specific autoantibodies and by the presence of autoreactive T cells. They are caused by a complex genetic predisposition that is attributable to multiple genetic variants, each with a moderate-to-low effect size. Most of the genetic variants associated with a particular autoimmune endocrine disease are shared between other systemic and organ-specific autoimmune and inflammatory diseases, such as rheumatoid arthritis, coeliac disease, systemic lupus erythematosus and psoriasis. Here, we review the shared and specific genetic background of autoimmune diseases, summarize their treatment options and discuss how identifying the genetic and environmental factors that predispose patients to an autoimmune disease can help in the diagnosis and monitoring of patients, as well as the design of new treatments.

Type 1 diabetes and celiac disease: The effects of gluten free diet on metabolic control

Type 1 diabetes mellitus is associated with celiac disease, with a prevalence that varies between 0.6% and 16.4%, according to different studies. After a diagnosis of celiac disease is confirmed by small bowel biopsy, patients are advised to commence a gluten-free diet (GFD). This dietary restriction may be particularly difficult for the child with diabetes, but in Europe (and in Italy) many food stores have targeted this section of the market with better labeling of products and more availability of specific GFD products. Treatment with a GFD in symptomatic patients has been shown to improve the symptoms, signs and complications of celiac disease. However, the effects of a GFD on diabetic control are less well established. Initial reports of improved hypoglycemic control were based on children who were diagnosed with celiac disease associated with malabsorption, but there have subsequently been reports of improvement in patients with type 1 diabetes with subclinical celiac disease. There are other studies reporting no effect, improved control and an improvement of hypoglycemic episodes. Moreover, in this review we wish to focus on low glycemic index foods, often suggested in people with type 1 diabetes, since they might reduce postprandial glycemic excursion and enhance long-term glycemic control. In contrast, GFD may be rich in high glycemic index foods that can increase the risk of obesity, insulin resistance and cardiovascular disease, worsening the metabolic control of the child with diabetes. Hence, it is important to evaluate the impact of a GFD on metabolic control, growth and nutritional status in children with type 1 diabetes.

Gliadin fragments and a specific gliadin 33-mer peptide close KATP channels and induce insulin secretion in INS-1E cells and rat islets of langerhans

In non-obese diabetic (NOD) mice, diabetes incidence is reduced by a gluten-free diet. Gluten peptides, such as the compound gliadin, can cross the intestinal barrier and may directly affect pancreatic beta cells. We investigated the effects of enzymatically-digested gliadin in NOD mice, INS-1E cells and rat islets. Six injections of gliadin digest in 6-week-old NOD mice did not affect diabetes development, but increased weight gain (20% increase by day 100). In INS-1E cells, incubation with gliadin digest induced a dose-dependent increase in insulin secretion, up to 2.5-fold after 24 hours. A similar effect was observed in isolated rat islets (1.6-fold increase). In INS-1E cells, diazoxide reduced the stimulatory effect of gliadin digest. Additionally, gliadin digest was shown to decrease current through K_ATP-channels. A specific gliadin 33-mer had a similar effect, both on current and insulin secretion. Finally, INS-1E incubation with gliadin digest potentiated palmitate-induced insulin secretion by 13% compared to controls. Our data suggest that gliadin fragments may contribute to the beta-cell hyperactivity observed prior to the development of type 1 diabetes.

Promotion of autoimmune diabetes by cereal diet in the presence or absence of microbes associated with gut immune activation, regulatory imbalance, and altered cathelicidin antimicrobial Peptide

We are exposed to millions of microbial and dietary antigens via the gastrointestinal tract, which likely play a key role in type 1 diabetes (T1D). We differentiated the effects of these two major environmental factors on gut immunity and T1D. Diabetes-prone BioBreeding (BBdp) rats were housed in specific pathogen-free (SPF) or germ-free (GF) conditions and weaned onto diabetes-promoting cereal diets or a protective low-antigen hydrolyzed casein (HC) diet, and T1D incidence was monitored. Fecal microbiota 16S rRNA genes, immune cell distribution, and gene expression in the jejunum were analyzed. T1D was highest in cereal-SPF (65%) and cereal-GF rats (53%) but inhibited and delayed in HC-fed counterparts. Nearly all HC-GF rats remained diabetes-free, whereas HC-fed SPF rats were less protected (7 vs. 29%). Bacterial communities differed in SPF rats fed cereal compared with HC. Cereal-SPF rats displayed increased gut CD3(+) and CD8α(+) lymphocytes, ratio of Ifng to Il4 mRNA, and Lck expression, indicating T-cell activation. The ratio of CD3(+) T cells expressing the Treg marker Foxp3(+) was highest in HC-GF and lowest in cereal-SPF rats. Resident CD163(+) M2 macrophages were increased in HC-protected rats. The cathelicidin antimicrobial peptide (Camp) gene was upregulated in the jejunum of HC diet-protected rats, and CAMP(+) cells colocalized with CD163. A cereal diet was a stronger promoter of T1D than gut microbes in association with impaired gut immune homeostasis.