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.

About 1 in 4 infants comes forward with prolonged crying, agitation, or infant colic (IC) during the first three months of life and is referred for medical evaluation. The pathogenesis remains poorly understood, as do its implications for future health. The aim of this narrative review was to critically examine and discuss the available literature on long-term consequences of excessive crying and/or colic. Most studies display an association between IC and the onset of functional gastrointestinal disorders (FGIDs) years later, probably related to the presence of common etiopathogenetic factors (environmental, dietary, intestinal dysmotility, visceral hypersensitivity). Although allergic disease in first-degree relatives may be a risk factor for IC, the latter does not appear to be a risk factor for subsequent atopic disease in the individual. Overall, there seems to be a relationship between IC and subsequent headaches, of the migraine type. Similarly, behavioral problems in children with a history of IC appear to be associated with higher parental stress scores. However, the current evidence is based on associations, and currently, a causal relationship between excessive crying and IC and long-term consequences remains not documented.

Background: the intestinal microbiota, a complex community vital to human health, is shaped by microbial competition and host-driven selective pressures. Among these microbes, Bifidobacterium plays a crucial role in early gut colonization during neonatal stages, where Bifidobacterium longum subspecies infantis (B. infantis) predominates and is particularly prevalent in healthy breastfed infants. Objectives: as we embark on a new era in nutrition of the pediatric population, this study seeks to examine the existing understanding regarding B. infantis, encompassing both preclinical insights and clinical evidence. Methods: through a narrative disceptation of the current literature, we focus on its genetic capacity to break down various substances that support its survival and dominance in the intestine. Results: using “omics” technologies, researchers have identified beneficial mechanisms of B. infantis, including the production of short-chain fatty acids, serine protease inhibitors, and polysaccharides. While B. infantis declines with age and in various diseases, it remains a widely used probiotic with documented benefits for infant and child health in numerous studies. Conclusions: the current scientific evidence underscores the importance for ongoing research and clinical trials for a deeper understanding of B. infantis’s role in promoting long-term health.

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.

Helicobacter pylori (HP) is a Gram-negative bacterium which finds its suitable habitat in the stomach. The infection affects about half of the global population with high variability in prevalence among regions and for age. HP is the main causative agent of chronic active gastritis, peptic and duodenal ulcers, and may be the primary cause of gastric cancer or MALT lymphoma. Due to the high rate of failure of eradication therapy in various countries and the increase in antibiotic resistance reported in the literature, there is an ever wider need to seek alternative therapeutic treatments. Probiotics seem to be a promising solution. In particular, the Limosilactobacillus reuteri (L. reuteri) species is a Gram-positive bacterium and is commonly found in the microbiota of mammals. L. reuteri is able to survive the gastric acid environment and bile and to colonize the gastric mucosa. This species is able to inhibit the growth of several pathogenic bacteria through different mechanisms, keeping the homeostasis of the microbiota. In particular, it is able to secrete reuterin and reutericycline, substances that exhibit antimicrobial properties, among other molecules. Through the secretion of these and the formation of the biofilm, it has been found to strongly inhibit the growth of HP and, at higher concentrations, to kill it. Moreover, it reduces the expression of HP virulence factors. In clinical trials, L. reuteri has been shown to decrease HP load when used as a single treatment, but has not achieved statistical significance in curing infected patients. As an adjuvant of standard regimens with antibiotics and pump inhibitors, L. reuteri can be used not only to improve cure rates, but especially to decrease gastrointestinal symptoms, which are a common cause of lack of compliance and interruption of therapy, leading to new antibiotic resistance.

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).