Gut Immunobiosis and Biomodulators

The human gastrointestinal (GI) tract hosts complex and dynamic populations of microorganisms (gut microbiota) in advantageous symbiosis with the host organism through sophisticated molecular cross-talk. The balance and diversification within microbial communities (eubiosis) are crucial for the immune and metabolic homeostasis of the host, as well as for inhibiting pathogen penetration. In contrast, compositional dysregulation of the microbiota (dysbiosis) is blamed for the determinism of numerous diseases. Although further advances in the so-called 'omics' disciplines are needed, dietary manipulation of the gut microbial ecosystem through biomodulators (prebiotics, probiotics, symbionts, and postbiotics) represents an intriguing target to stabilize and/or restore eubiosis. Recently, new approaches have been developed for the production of infant formulas supplemented with prebiotics (human milk oligosaccharides [HMOs], galacto-oligosaccharides [GOS], fructo-oligosaccharides [FOS]), probiotics, and postbiotics to obtain formulas that are nutritionally and biologically equivalent to human milk (closer to the reference).

Intestinal Barrier Dysfunction and Microbiota–Gut–Brain Axis: Possible Implications in the Pathogenesis and Treatment of Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with multifactorial etiology, characterized by impairment in two main functional areas: (1) communication and social interactions, and (2) skills, interests and activities. ASD patients often suffer from gastrointestinal symptoms associated with dysbiotic states and a “leaky gut.” A key role in the pathogenesis of ASD has been attributed to the gut microbiota, as it influences central nervous system development and neuropsychological and gastrointestinal homeostasis through the microbiota–gut–brain axis. A state of dysbiosis with a reduction in the Bacteroidetes/Firmicutes ratio and Bacteroidetes level and other imbalances is common in ASD. In recent decades, many authors have tried to study and identify the microbial signature of ASD through in vivo and ex vivo studies. In this regard, the advent of metabolomics has also been of great help. Based on these data, several therapeutic strategies, primarily the use of probiotics, are investigated to improve the symptoms of ASD through the modulation of the microbiota. However, although the results are promising, the heterogeneity of the studies precludes concrete evidence. The aim of this review is to explore the role of intestinal barrier dysfunction, the gut–brain axis and microbiota alterations in ASD and the possible role of probiotic supplementation in these patients.

Risk of obesity during a gluten-free diet in pediatric and adult patients with celiac disease: a systematic review with meta-analysis

CONTEXT

Obesity is a significant risk factor for many pathological conditions. Whether a gluten-free diet (GFD) is a risk factor for overweight or obesity remains controversial.

OBJECTIVE

The primary aim of this study was to assess the prevalence of body mass index (BMI) categories at disease presentation and the variation in BMI category from underweight/normal to overweight/obese and vice versa during a GFD.

DATA SOURCES

PubMed, Scopus, and Web of Science databases were searched through February 2021 for retrospective, cross-sectional, and prospective studies reporting BMI categories at disease diagnosis and during a GFD.

DATA EXTRACTION

Data were extracted by 2 reviewers independently. Disagreements were resolved by consensus; a third reviewer was consulted, if necessary. Risk of bias was assessed with the Cochrane ROBINS-I tool.

DATA ANALYSIS

Subgroup analysis based on age (pediatric/adult patients), study design (prospective, cross-sectional, retrospective), and duration of GFD was performed.. Forty-five studies were selected (7959 patients with celiac disease and 20 524 healthy controls). The mean BMI of celiac patients at presentation was significantly lower than that of controls (P < 0.001). During a GFD, the mean BMI increased significantly (mean difference = 1.14 kg/m2 [95%CI, 0.68-1.60 kg/m2]; I2 = 82.8%; P < 0.001), but only 9% of patients (95%CI, 7%-12%; I2 = 80.0%) changed from the underweight/normal BMI category to the overweight/obese category, while 20% (95%CI, 11%-29%; I2 = 85.8%) moved into a lower BMI category.

CONCLUSION

Most celiac patients had a normal BMI at presentation, although the mean BMI was significantly lower than that of controls. A GFD does not increase the risk of becoming overweight/obese, especially in children. The quality of several studies was suboptimal, with moderate or high overall risk of bias and heterogeneity.

Twelve Months with COVID-19: What Gastroenterologists Need to Know

Corona virus disease-19 (COVID-19) is the latest global pandemic. COVID-19 is mainly transmitted through respiratory droplets and, apart from respiratory symptoms, patients often present with gastrointestinal symptoms and liver involvement. Given the high percentage of COVID-19 patients that present with gastrointestinal symptoms (GIS), in this review, we report a practical up-to-date reference for the physician in their clinical practice with patients affected by chronic gastrointestinal (GI) diseases (inflammatory bowel disease, coeliac disease, chronic liver disease) at the time of COVID-19. First, we summarised data on the origin and pathogenetic mechanism of SARS-CoV-2. Then, we performed a literature search up to December 2020 examining clinical manifestations of GI involvement. Next, we illustrated and summarised the most recent guidelines on how to adhere to GI procedures (endoscopy, liver biopsy, faecal transplantation), maintaining social distance and how to deal with immunosuppressive treatment. Finally, we focussed on some special conditions such as faecal-oral transmission and gut microbiota. The rapid accumulation of information relating to this condition makes it particularly essential to revise the literature to take account of the most recent publications for medical consultation and patient care.

Use of Limosilactobacillus reuteri DSM 17938 in paediatric gastrointestinal disorders: an updated review

Strains of lactobacilli are the most widely used probiotics and can be found in a large variety of food products and food supplements throughout the world. In this study, the evidence on Limosilactobacillus reuteri DSM 17938 (LR DSM 17938) has been reviewed. This species secretes reuterin and other substances singularly or in microvesicles, inhibiting pathogen growth and interacting with the intestinal microbiota and mucosa, restoring homeostasis. The use of LR DSM 17938 has been exploited in several pathological conditions. Preclinical research has shown that this probiotic can ameliorate dysbiosis and, by interacting with intestinal mucosal cells, can raise the pain threshold and promote gastrointestinal motility. These aspects are amongst the significant components in functional gastrointestinal disorders, such as colic and regurgitation in infants, functional abdominal pain and functional constipation in children and adolescents. This strain can decrease the duration of acute diarrhoea and hospitalization for acute gastroenteritis but does not seem to prevent nosocomial diarrhoea and antibiotic-associated diarrhoea. Because of its ability to survive in the gastric environment, it has been tested in Helicobacter pylori infection, showing a significant decrease of antibiotic-associated side effects and a tendency to increase the eradication rate. Finally, all these studies have shown the excellent safety of LR DSM 17938 even at higher dosages. In conclusion data from various clinical trials here reviewed can guide the clinician to find the correct dose, frequency of administration, and therapy duration.

Esophageal Eosinophilia and Eosinophilic Esophagitis in Celiac Children: A Ten Year Prospective Observational Study

The association between eosinophilic esophagitis and celiac disease is still controversial and its prevalence is highly variable. We aimed to investigate the prevalence of esophageal eosinophilia and eosinophilic esophagitis in a large group of children with celiac disease, prospectively followed over 11 years.

METHODS

Prospective observational study performed between 2008 and 2019. Celiac disease diagnosis was based on ESPGHAN criteria. At least four esophageal biopsies were sampled in patients who underwent endoscopy. The presence of at least 15 eosinophils/HPF on esophageal biopsies was considered suggestive of esophageal eosinophilia; at the same time, eosinophilic esophagitis was diagnosed according to the International Consensus Diagnostic Criteria for Eosinophilic Esophagitis.

RESULTS

A total of 465 children (M 42% mean age 7.1 years (range: 1-16)) were diagnosed with celiac disease. Three hundred and seventy patients underwent endoscopy, and esophageal biopsies were available in 313. The prevalence of esophageal eosinophilia in children with celiac disease was 1.6% (95% CI: 0.54-2.9%). Only one child was diagnosed as eosinophilic esophagitis; we calculated a prevalence of 0.3% (95% CI: 0.2-0.5%). The odds ratio for an association between eosinophilic esophagitis and celiac disease was at least 6.5 times higher (95% CI: 0.89-47.7%; p = 0.06) than in the general population.

CONCLUSION

The finding of an increased number of eosinophils (>15/HPF) in celiac patients does not have a clinical implication or warrant intervention, and therefore we do not recommend routine esophageal biopsies unless clinically indicated.

Retrospective Study on Breastfeeding Practices by SARS-COV-2 Positive Mothers in a High Risk Area for Coronavirus Infection

BACKGROUND

During the pandemic of SARS-Cov-2, among other clinical and public health issues, a major concern raised by SARS-CoV-2 is the possibility of transmission of the infection from mother to child in the perinatal period. This has placed a question mark on the safety of breastfeeding, with ambiguity on the joint management of SARS-CoV-2 positive or suspected mothers and their children. It was aimed to evaluate breastfeeding rates for newborns of asymptomatic SARS-CoV-2 positive mothers who were temporarily separated from their babies at birth, compared to those who were not separated.

RESULTS

Babies who were not isolated from their mothers at delivery were significantly more likely to be breastfed and were at no higher risk of infection with SARS-CoV-2.

CONCLUSION

Following the World Health Organization (WHO) recommendations and strict hand and mask hygiene measures, breastfeeding practices can be established and maintained through rooming-in, thus promoting the mother-child bond without compromising the safety of the newborn.

Iodine Absorption in Celiac Children: A Longitudinal Pilot Study

Background: non-autoimmune thyroid disorder is a common finding in celiac patients, more frequent than in the general population. An impairment of iodine absorption has been hypothesized, but it has never been investigated so far. We aimed to evaluate the iodine absorption in children and adolescents with newly diagnosed celiac disease. Methods: 36 consecutive celiac patients (age 7.4 years, range 2.4-14.5 years) before starting a gluten-free diet (GFD) were enrolled. We assayed the urinary iodine concentration (UIC) in a 24-h urine sample, at baseline (T0) after 3 (T1) and 12 months (T2) of GFD. Results: UIC at T0 was 64 μg/L (IQR 45-93.25 μg/L) with an iodine deficiency rate of 77.8%. UIC was not different according to histological damage, clinical presentation (typical vs atypical); we found no correlation with the thyroid function tests and auxological parameters. UIC was not statistically different at T1 (76 μg/L) and T2 (89 μg/L) vs T0. UIC at T2 was similar between patients with positive and negative anti-transglutaminase antibodies at T2. No patients presented overt hypothyroidism during the study. Conclusions: We found that iodine absorption in celiac children is impaired compared to the general population; it increases slightly, but not significantly, during the GFD. We should regularly reinforce the need for a proper iodine intake in celiac disease patients to reduce iodine deficiency risk.

Anti-Inflammatory and Immunomodulatory Effects of Probiotics in Gut Inflammation: A Door to the Body

Hosting millions of microorganisms, the digestive tract is the primary and most important part of bacterial colonization. On one side, in cases of opportunistic invasion, the abundant bacterial population inside intestinal tissues may face potential health problems such as inflammation and infections. Therefore, the immune system has evolved to sustain the host-microbiota symbiotic relationship. On the other hand, to maintain host immune homeostasis, the intestinal microflora often exerts an immunoregulatory function that cannot be ignored. A field of great interest is the association of either microbiota or probiotics with the immune system concerning clinical uses. This microbial community regulates some of the host's metabolic and physiological functions and drives early-life immune system maturation, contributing to their homeostasis throughout life. Changes in gut microbiota can occur through modification in function, composition (dysbiosis), or microbiota-host interplays. Studies on animals and humans show that probiotics can have a pivotal effect on the modulation of immune and inflammatory mechanisms; however, the precise mechanisms have not yet been well defined. Diet, age, BMI (body mass index), medications, and stress may confound the benefits of probiotic intake. In addition to host gut functions (permeability and physiology), all these agents have profound implications for the gut microbiome composition. The use of probiotics could improve the gut microbial population, increase mucus-secretion, and prevent the destruction of tight junction proteins by decreasing the number of lipopolysaccharides (LPSs). When LPS binds endothelial cells to toll-like receptors (TLR 2, 4), dendritic cells and macrophage cells are activated, and inflammatory markers are increased. Furthermore, a decrease in gut dysbiosis and intestinal leakage after probiotic therapy may minimize the development of inflammatory biomarkers and blunt unnecessary activation of the immune system. In turn, probiotics improve the differentiation of T-cells against Th2 and development of Th2 cytokines such as IL-4 and IL-10. The present narrative review explores the interactions between gut microflora/probiotics and the immune system starting from the general perspective of a biological plausibility to get to the in vitro and in vivo demonstrations of a probiotic-based approach up to the possible uses for novel therapeutic strategies.

Bacterial-Based Strategies to Hydrolyze Gluten Peptides and Protect Intestinal Mucosa

Gluten is a mixture of proteins highly resistant to hydrolysis, resulting in the emergence of toxic peptides responsible for gluten-related disorders. Currently, a gluten-free diet (GFD) is the unique proven therapy for celiac disease (CD). Several research groups and pharmaceutical companies are developing new nondietetic therapeutic strategies for CD. Probiotics are viable microorganisms thought to have a healthy effect on the host. The proteolytic mechanism of lactic acid bacteria comprises an extracellular serine protease, di- and oligopeptide-specific transport systems, and several intracellular peptidases that might affect gluten degradation. Therefore, probiotic supplementation is an attractive therapy because of its possible anti-inflammatory and immunomodulatory properties. Several studies have been performed to assess the effectiveness of various specific probiotic strains, showing positive effects on immune-modulation (inhibition of pro-inflammatory cytokine TNF-α) restoring gut microbiota and decrease of immunogenic peptides. The present review aims to summarize the current knowledge on the ability of probiotic strain (single or mixtures) to digest gliadin peptides in vitro and to modulate the inflammatory response in the gut.

Preventing and Treating Colic

Colic is a common and distressing functional gastrointestinal disorder during infancy. It is a behavioral phenomenon in infants aged 1-4 months involving prolonged inconsolable crying and agitated status with multifactorial etiology. Colic can be considered as a benign, self-limited process because the baby normally grows and feeds even with transient irritable mood. Nevertheless, infantile colic is a common difficulty causing anxiety during parenthood and a recurrent reason for them to seek medical help, especially if it is the first child. The causes of colic can be classified as non-gastrointestinal or gastrointestinal. The former includes altered feeding techniques, modified child-parent relationship, immaturity of central nervous system, behavioral etiology, and maternal smoking or nicotine replacement therapy. Instead, the latter involves inadequate production of lactase enzyme, cow's milk protein intolerance, alteration of intestinal microbiota, gastrointestinal immaturity, or inflammation which causes intestinal hyperperistalsis due to increase in serotonin secretion and motilin receptor expression.Probiotics may play a crucial part in the manipulation of the microbiota. Probiotic administration is likely to maintain intestinal homeostasis through the modulation of permeability and peristalsis, influencing the gut-brain axis and inhibiting hypersensitivity. This is a decisive field in the development of preventive and therapeutic strategies for infantile colic. However, further studies are needed for each specific formulation in order to better characterize pharmacodynamic and pharmacokinetic properties and to evaluate their application as a possible preventive strategy if administered early during infancy against the later development of pain-related FGIDs.