Proton pump inhibitors (PPIs) are common medications within the practice of gastroenterology. These drugs, which act through the irreversible inhibition of the hydrogen/potassium pump (H+/K+-ATPase pump) in the gastric parietal cells, are used in the treatment of several acid-related disorders. PPIs are generally well tolerated but, through the long-term reduction of gastric acid secretion, can increase the risk of an imbalance in gut microbiota composition ( i.e ., dysbiosis). The gut microbiota is a complex ecosystem in which microbes coexist and interact with the human host. Indeed, the resident gut bacteria are needed for multiple vital functions, such as nutrient and drug metabolism, the production of energy, defense against pathogens, the modulation of the immune system and support of the integrity of the gut mucosal barrier. The bacteria are collected in communities that vary in density and composition within each segment of the gastrointestinal (GI) tract. Therefore, every change in the gut ecosystem has been connected to an increased susceptibility or exacerbation of various GI disorders. The aim of this review is to summarize the recently available data on PPI-related microbiota alterations in each segment of the GI tract and to analyze the possible involvement of PPIs in the pathogenesis of several specific GI diseases.

Inflammatory bowel diseases are chronic diseases affecting the gastrointestinal tract, whose major forms are represented by Crohn's disease (CD) and ulcerative colitis (UC). Their etiology is still unclear, although several factors have been identified as major determinants for induction or relapses. Among these, the role of the “forgotten organ”, gut microbiota, has become more appreciated in recent years. The delicate symbiotic relationship between the gut microbiota and the host appears to be lost in IBD. In this perspective, several studies have been conducted to assess the role of prebiotics and probiotics in gut microbiota modulation. This is a minireview aimed to address in an easy format (simple questions-simple answers) some common issues about the theme. An update on the role of selected constituents of gut microbiota in the pathogenesis of IBD is presented together with the analysis of the efficacy of gut microbiota modulation by prebiotics and probiotics administration in the management of IBD.

Cow's milk protein hydrolysate formulae have been developed to lower or eliminate the allergenicity of cow's milk proteins, and to reduce the antigenic load and the risk of sensitization. Cross-reactivity between different hydrolysate formulae and cow's milk proteins has been demonstrated. We have studied 20 children (median age 31 months, range 15-76 months) with a history of IgE-mediated cow's milk allergy. All the children had immediate allergic respiratory and/or cutaneous and/or gastro-intestinal reactions to cow's milk ingestion. In addition, the children had positive prick skin tests and positive RAST to cow's milk. Prick skin test, RAST, and double-blind placebo controlled food challenges were performed with three different hydrolysate formulae: a casein hydrolysate formula and two whey formulae, one partially and one extensively hydrolyzed. All 20 children had immediate allergic reactions after the challenge test with cow's milk. Only 2/20 children had a positive challenge test with a casein hydrolysate formula (Alimentum): one developed asthma and one urticaria. Two of the 15 children challenged with an extensively hydrolysed whey formula (Profylac) developed perioral erythema. Nine out of 20 children had a positive challenge test with a partially hydrolysed whey formula (Nidina H.A.): four developed asthma, three urticaria and two lip oedema. All children had positive prick skin tests to cow's milk proteins (casein and/or lactalbumin); 9 to Nidina H.A.; 3 to Profylac, and 3 to Alimentum. Specific IgE antibodies to cow's milk were present in all children; in 13 to Nidina H.A., in 4 to Profylac, and in 3 to Alimentum.

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Introduction. Helicobacter pylori eradication therapy has the potential burden of antibiotic-associated gastrointestinal (GI) side effects. The occurrence of side effects is among the major drawbacks of such regimens. GI manifestations may be related to alterations in the intestinal microflora. Probiotics can prevent or reduce antibiotic-associated side effects and have an inhibitory effect on H. pylori. Methods. To define the efficacy of Lactobacillus reuteri supplementation in H. pylori eradication and in preventing GI-associated side effects during a second-line levofloxacin triple therapy. 90 H. pylori-positive patients receive for 7 days a second-line triple therapy with esomeprazole, levofloxacin, and amoxicillin with L. reuteri for 14 days (group 1) and without probiotic supplementation (group 2). Each subject received a validated questionnaire to record symptoms everyday for 4 weeks from the start of therapy. H. pylori status and side effects were assessed 6 weeks after treatment. Results. The eradication rate was significantly influenced by probiotic supplementation with L. reuteri (group 1: 36/45, 80%; group 2: 28/45 62%; P < 0.05). The incidence of nausea and diarrhoea in group 1 was significantly lower than that in group 2. Conclusion. In H. pylori-positive subjects L. reuteri supplementation increases the eradication rate while reducing the incidence of the most common side effects associated with antibiotic therapy in second-line treatment.

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Recently, the finding of high plasma concentration of phyto-oestrogens in soy protein formula (SPF) fed children has focused scientific attention on the phyto-oestrogens (isoflavones genistein, daidzein, and their glycosides) contained in SPFs. The aim of this study was to evaluate some hormonal and metabolic effects of long-term (more than 6 months) SPF feeding. We enrolled 48 children, mean age 37 months (range 7-96 months), 27 males and 21 females. All children underwent physical examination. Bone age, urinary markers of bone metabolism, serum levels of bone alkaline phosphatase, osteocalcin, 17beta-oestradiol, and intact parathyroid hormone were measured. Eighteen healthy children represented the control group. No abnormalities were observed in auxological parameters; none of the enrolled girls showed signs/symptoms of precocious puberty and none of the boys presented gynecomastia; bone age was within the normal range. The serum level of bone alkaline phosphatase, osteocalcin, 17beta-oestradiol, and intact parathyroid hormone, and the urinary levels of the markers of bone metabolism were all within normal values. We conclude that long-term feeding with SPFs in early life does not seem to produce oestrogen-like hormonal effects.

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