Distinctive Microbial Signatures and Gut-Brain Crosstalk in Pediatric Patients with Coeliac Disease and Type 1 Diabetes Mellitus

Celiac disease gut microbiome studies in the third millennium: reviewing the findings and gaps of available literature

Celiac disease is an autoimmune enteropathy caused by the ingestion of minute amounts of gluten in a subset of genetically predisposed individuals. Its onset occurs at different ages and with variable symptoms. The gut microbiome may contribute to this variability. This review aims to provide an overview of the available research on celiac disease gut microbiome and identify the knowledge gap that could guide future studies. Following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analysis extension for Scoping Reviews (PRISMA-ScR), four electronic databases were searched for literature from January 2000 to July 2023 addressing celiac disease gut microbiome characterization using next-generation sequencing (NGS) approaches. From the 489 publications retrieved, 48 publications were selected and analyzed, focusing on sample characterization (patients, controls, and tissues) and methodologies used for NGS microbiome analysis and characterization. The majority of the selected publications regarded children and adults, and four were randomized clinical trials. The number of participants per study greatly varied and was typically low. Feces were the most frequently tested sample matrix, and duodenal samples were analyzed in one-third of the studies. Incomplete and diverse information on the methodological approaches and gut microbiome results was broadly observed. While similar trends regarding the relative abundance of some phyla, such as Pseudomonadota (former Proteobacteria), were detected in some studies, others contradicted those results. The observed high variability of technical approaches and possibly low power and sample sizes may prevent reaching a consensus on celiac disease gut microbiome composition. Standardization of research protocols to allow reproducibility and comparability is required, as interdisciplinary collaborations to further data analysis, interpretation, and, more importantly, health outcome prediction or improvement.

Implications of Celiac Disease in Prospective Corneal Refractive Surgery Patients: A Narrative Review

Celiac disease (CeD) is a prevalent autoimmune disorder incited by gluten consumption, resulting in intestinal damage. Affecting approximately one in 133 people globally, CeD often remains undiagnosed due to its varied clinical presentations. The prevalence and diagnosis of CeD are influenced by several factors, including demographics and genetics, and it often coexists with other autoimmune diseases. Thus, the objective of this paper was to review the literature on ophthalmic manifestations of CeD and to create preliminary considerations for these patients wishing to undergo elective corneal refractive surgery (CRS). A literature review was conducted through July 2024, and relevant search terms were used to identify contributing papers. The review enabled the development of detailed considerations for the ocular manifestations of CeD and recommended management strategies for healthcare teams before and following CRS. The 24 papers included in this study illustrate that nutritional deficiencies and autoimmune concerns linked to CeD have distinctive ocular presentations. Based on these findings, patients with CeD may exhibit unconventional ocular manifestations beyond their typical gastrointestinal symptoms, such as decreased endothelial cell density (ECD), vitamin A deficiency leading to dryness, altered corneal nerve density, cataracts, uveitis, changes in choroidal thickness, papilledema, and neurological issues such as nystagmus. Patients with CeD may also experience synergistic impacts from concomitant autoimmune conditions such as Type 1 Diabetes Mellitus (T1DM) in addition to the coexistence of thyroid ophthalmopathy. Recognizing that CeD is an autoimmune disorder that can be exacerbated by other conditions, it is essential to conduct a thorough evaluation for elective CRS. Due to the variability in ocular manifestations among CeD patients, individualized evaluations are crucial for determining surgical candidacy and optimizing outcomes, especially for patients who may not be well controlled. Evaluations are likely to encompass a subjective assessment through a questionnaire exploring the patient's past medical history related to CeD. These questions can range from inquiring about general past medical history related to CeD regarding dietary gluten intake and weight loss to joint pain and cognitive impairments such as brain fog. Clinicians should also perform a comprehensive objective assessment utilizing slit-lamp biomicroscopy, Schirmer test, tear break-up time (TBUT), optical coherence tomography (OCT), Scheimpflug imaging, or fundoscopy. Although there is currently no specific information regarding CRS recommendations for patients with CeD, we believe the considerations outlined in this paper should serve as preliminary guidelines for clinicians. While our findings have formed considerations for future healthcare teams, further research is needed to fully understand the impact of CeD on CRS outcomes and refine these recommendations.

A comparison of the breast milk microbiota from women diagnosed with gestational diabetes mellitus and women without gestational diabetes mellitus

BACKGROUND

Human breast milk (HBM) is a contributing factor in modulating the infant's gut microbiota, as it contains bacteria that are directly transferred to the infant during breastfeeding. It has been shown that children of women diagnosed with gestational diabetes mellitus (GDM) have a different gut microbiota compared to children of women without GDM. Our hypothesis is therefore that women with GDM have a different HBM microbiota, which may influence the metabolic function and capacity of the child later in life. The aim of this study was to investigate whether women with GDM have a different breast milk microbiota 1-3 weeks postpartum compared to women without GDM.

METHODS

In this case-control study, a total of 45 women were included: 18 women with GDM and 27 women without GDM. A milk sample was collected from each participant 1 to 3 weeks postpartum and the bacterial composition was examined by 16 S rRNA gene sequencing targeting the V4 region.

RESULTS

High relative abundances of Streptococcus and Staphylococcus were present in samples from both women with and without GDM. No difference could be seen in either alpha diversity, beta diversity, or specific taxa between groups.

CONCLUSION

Our results did not support the existence of a GDM-associated breast milk microbiota at 1-3 weeks postpartum. Further research is needed to fully understand the development of the gut microbiota of infants born to mothers with GDM.

Could Celiac Disease and Overweight/Obesity Coexist in School-Aged Children and Adolescents? A Systematic Review

Background: Celiac disease (CD) is a multifactorial, immune-mediated enteropathic disorder that may occur at any age with heterogeneous clinical presentation. In the last years, unusual manifestations have become very frequent, and currently, it is not so uncommon to diagnose CD in subjects with overweight or obesity, especially in adults; however, little is known in the pediatric population. This systematic review aims to evaluate the literature regarding the association between CD and overweight/obesity in school-age children. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. An electronic database search of articles published in the last 20 years in English was carried out in Web of Sciences, PubMed, and Medline. The quality of the included studies was assessed by using the STrengthening the Reporting of OBservational studies in Epidemiology statement. Results: Of the 1396 articles identified, 9 articles, investigating overweight/obesity in children/adolescents affected by CD or screening CD in children/adolescents with overweight/obesity, met the inclusion criteria. Overall, the results showed that the prevalence of overweight or obesity in school-age children (6-17 years) affected by CD ranged between 3.5% and 20%, highlighting that the coexistence of CD with overweight/obesity in children is not uncommon as previously thought. Conclusion: Although CD has been historically correlated with being underweight due to malabsorption, it should be evaluated also in children with overweight and obesity, especially those who have a familiar predisposition to other autoimmune diseases and/or manifest unusual symptoms of CD.

Molecular basis of phytochemical-gut microbiota interactions

Dysbiosis-associated molecular pathology is significantly involved in developing and perpetuating metabolic disorders, disrupting host energy regulation, and triggering inflammatory signaling cascades, insulin resistance, and metabolic dysfunction. Concurrently, numerous phytoconstituents are able to interact with the gut microbiota and produce bioactive metabolites that influence host cellular pathways, inflammation, and metabolic processes. These effects include improved insulin sensitivity, lipid metabolism regulation, and suppression of chronic inflammation, highlighting the therapeutic potential of phytoconstituents against metabolic abnormalities. Understanding this symbiotic relationship and the underlying molecular cascades offers innovative strategies for tailored interventions and promising therapeutic approaches to address the growing burden of metabolic disease.

Acquired susceptibility to autoimmune diseases in pediatric patients with Escherichia coli infection: A population-matched retrospective cohort study

BACKGROUND

Escherichia coli (E.coli) infection has been proposed to play an important role as an initial trigger in the development of autoimmunity via molecular mimicry. However, there has been no preliminary cohort study to establish the association of E.coli infection with autoimmune diseases. Therefore, we conducted a large scale, population-matched cohort study to determine the risk of autoimmune disease among patients with exposure to E.coli.

METHODS

Utilizing the National Health Insurance Service database, we retrospectively analyzed a total of 259,875 Korean children that consisted of 23,625 exposed and 236,250 unexposed persons from January 1, 2002 to December 31, 2017. The exposed cohort was defined as patients diagnosed with E.coli infection. Unexposed controls were matched by birth year and sex at a 1:10 ratio for each exposed patient, using incidence density sampling. The primary outcome was autoimmune disease development. We used the Cox model to estimate the risks of autoimmune diseases among patients diagnosed with E.coli infection.

RESULTS

Over a mean follow-up of 10 years, there were 1455 autoimmune disease cases among exposed patients (incidence rate, 63.6 per 10,000 person-years) and 11,646 autoimmune disease cases among unexposed persons (incidence rate, 50.4 per 10,000 person-years), with an adjusted hazard ratio (HR) of 1.254 (95% CI 1.187-1.325). E.coli infection was associated with increased risks of autoimmune diseases; Reactive arthritis, HR 1.487, 95% CI 1.131-1.956; Henoch Schönlein purpura, HR 1.265, 95% CI 1.050-1.524; Systemic lupus erythematosus, HR 1.838, 95% CI 1.165-2.898; Sjögren's syndrome, HR 2.002, 95% CI 1.342-2.987; IgA nephropathy, HR 1.613, 95% CI 1.388-1.874. Kaplan-Meier cumulative incidence curves also showed a significant association between E.coli infection and incident autoimmune disease (p < 0.0001). This relationship was not only independent of demographic variables, but also remained consistent across various sensitivity analyses. On the other hand, patients with longer hospital stay for E.coli infection were at a higher risk of autoimmune disease (p = 0.0003), and the risk of autoimmune disease also tended to increase, as the frequency of E.coli infection was higher. Moreover, the relative risk of autoimmune disease seemed to be attenuated by use of antibiotics and a history of intestinal infectious disease, but elevated by coexistence of other autoimmune diseases.

CONCLUSIONS

Our cohort study indicates that E.coli infection was significantly associated with increased susceptibility to autoimmune diseases, even after adjusting for different factors. Thus, among environmental factors, a previous history of E.coli infection could be a predisposing risk factor in the development of autoimmune diseases.

Dysbiosis versus diabesity: pathological signaling and promising therapeutic strategies

A healthy life depends on the inseparable relationship between a host and the gut microbiota. A healthy gut microbiota regulates intestinal integrity, whereas an unbalanced gut microbiota contributes to junctional remodeling and leads to dysbiosis. Bacterial infiltration and dysbiosis are reported to activate a series of pathological cascades that trigger metabolic abnormalities, including diabesity. Conversely, recent studies revealed that the incidence of dysbiosis itself is fuelled by diabesity. In this review, we highlight the molecular aspects of multifaceted pathological signaling between dysbiosis and diabetes that could pave the way for new drug discovery. Moreover, to reinstate the gut microbiota and restrict the epidemic of dysbiosis and diabesity, we also scrutinize a promising therapeutic strategy that can challenge the pathological interlink. Teaser: Dysbiosis and diabesity are closely related and can influence each other. Dysbiosis can worsen diabesity, whereas diabesity can affect the gut microbiota. Thus, to prevent and treat diabesity, it is important to understand this complex interplay.

Celiac Disease and Neurological Manifestations: From Gluten to Neuroinflammation

Celiac disease (CD) is a complex multi-organ disease with a high prevalence of extra-intestinal involvement, including neurological and psychiatric manifestations, such as cerebellar ataxia, peripheral neuropathy, epilepsy, headache, cognitive impairment, and depression. However, the mechanisms behind the neurological involvement in CD remain controversial. Recent evidence shows these can be related to gluten-mediated pathogenesis, including antibody cross-reaction, deposition of immune-complex, direct neurotoxicity, and in severe cases, vitamins or nutrients deficiency. Here, we have summarized new evidence related to gut microbiota and the so-called "gut-liver-brain axis" involved in CD-related neurological manifestations. Additionally, there has yet to be an agreement on whether serological or neurophysiological findings can effectively early diagnose and properly monitor CD-associated neurological involvement; notably, most of them can revert to normal with a rigorous gluten-free diet. Moving from a molecular level to a symptom-based approach, clinical, serological, and neurophysiology data might help to disentangle the many-faceted interactions between the gut and brain in CD. Eventually, the identification of multimodal biomarkers might help diagnose, monitor, and improve the quality of life of patients with "neuroCD".

Microbial dysbiosis in the gut drives systemic autoimmune diseases

Trillions of microbes survive and thrive inside the human body. These tiny creatures are crucial to the development and maturation of our immune system and to maintain gut immune homeostasis. Microbial dysbiosis is the main driver of local inflammatory and autoimmune diseases such as colitis and inflammatory bowel diseases. Dysbiosis in the gut can also drive systemic autoimmune diseases such as type 1 diabetes, rheumatic arthritis, and multiple sclerosis. Gut microbes directly interact with the immune system by multiple mechanisms including modulation of the host microRNAs affecting gene expression at the post-transcriptional level or production of microbial metabolites that interact with cellular receptors such as TLRs and GPCRs. This interaction modulates crucial immune functions such as differentiation of lymphocytes, production of interleukins, or controlling the leakage of inflammatory molecules from the gut to the systemic circulation. In this review, we compile and analyze data to gain insights into the underpinning mechanisms mediating systemic autoimmune diseases. Understanding how gut microbes can trigger or protect from systemic autoimmune diseases is crucial to (1) tackle these diseases through diet or lifestyle modification, (2) develop new microbiome-based therapeutics such as prebiotics or probiotics, (3) identify diagnostic biomarkers to predict disease risk, and (4) observe and intervene with microbial population change with the flare-up of autoimmune responses. Considering the microbiome signature as a crucial player in systemic autoimmune diseases might hold a promise to turn these untreatable diseases into manageable or preventable ones.

Tipping the Balance: Vitamin D Inadequacy in Children Impacts the Major Gut Bacterial Phyla

Vitamin D inadequacy appears to be on the rise globally, and it has been linked to an increased risk of osteoporosis, as well as metabolic, cardiovascular, and autoimmune diseases. Vitamin D concentrations are partially determined by genetic factors. Specific single nucleotide polymorphisms (SNPs) in genes involved in vitamin D transport, metabolism, or binding have been found to be associated with its serum concentration, and these SNPs differ among ethnicities. Vitamin D has also been suggested to be a regulator of the gut microbiota and vitamin D deficiency as the possible cause of gut microbial dysbiosis and inflammation. This pilot study aims to fill the gap in our understanding of the prevalence, cause, and implications of vitamin D inadequacy in a pediatric population residing in Qatar. Blood and fecal samples were collected from healthy subjects aged 4–14 years. Blood was used to measure serum metabolite of vitamin D, 25-hydroxycholecalciferol 25(OH)D. To evaluate the composition of the gut microbiota, fecal samples were subjected to 16S rRNA gene sequencing. High levels of vitamin D deficiency/insufficiency were observed in our cohort with 97% of the subjects falling into the inadequate category (with serum 25(OH)D < 75 nmol/L). The CT genotype in rs12512631, an SNP in the GC gene, was associated with low serum levels of vitamin D (ANOVA, p = 0.0356) and was abundant in deficient compared to non-deficient subjects. Overall gut microbial community structure was significantly different between the deficient (D) and non-deficient (ND) groups (Bray Curtis dissimilarity p = 0.049), with deficient subjects also displaying reduced gut microbial diversity. Significant differences were observed among the two major gut phyla, Firmicutes (F) and Bacteroidetes (B), where deficient subjects displayed a higher B/F ratio (p = 0.0097) compared to ND. Vitamin D deficient children also demonstrated gut enterotypes dominated by the genus Prevotella as opposed to Bacteroides. Our findings suggest that pediatric vitamin D inadequacy significantly impacts the gut microbiota. We also highlight the importance of considering host genetics and baseline gut microbiome composition in interpreting the clinical outcomes related to vitamin D deficiency as well as designing better personalized strategies for therapeutic interventions.

New Evidence in the Pathogenesis of Celiac Disease and Type 1 Diabetes Mellitus: A Systematic Review

Celiac disease (CD) and type 1 diabetes mellitus (T1DM) are autoimmune diseases that coexist frequently. These illnesses share a common genetic background. This study aims to review the different pathophysiologic mechanisms that have been studied about the coexistence of CD and T1DM, to contrast them, and to summarize their specific role in these autoimmune diseases. We conducted a systematic review following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) checklist and used the Medical Subject Headings (MeSH) search strategy to obtain relevant articles. We found 585 papers which were reduced to 355 after removing duplicates. Later, the filters and inclusion/exclusion criteria were applied which ended the search with 78 articles. Finally, we reviewed the articles that contained information about the pathogenesis of CD and T1DM, their coexistence, and how the pathogenesis impacts clinical outcomes. The reviewed studies strongly conclude that the presence of human leukocyte antigen (HLA) genes DQ2 and DQ8 are high-risk for developing the coexistence of CD and T1DM. We found that killer immunoglobulin-like receptor (KIR) genes, enterovirus infection in gut cells, and gut microbiota dysbiosis with the predominance of Bacteroides spp. also play a role in the pathogenesis and development of symptoms of CD in patients with the previous diagnosis of T1DM. CD4+ and CD8+ cell levels vary among patients and studies, consequently, more study on this topic is needed.