Immune system and gut microbiota senescence in elderly IBD patients

In inflammatory bowel disease (IBD), the loss of immune tolerance against gut microbiota causes chronic inflammation and the progressive accumulation of organ damage in genetically susceptible individuals. In the elderly, IBD is often characterized by a different disease behavior when compared with pediatric and young adult disease. Besides disease behavior, another aspect of the multifaceted impact of age on elderly IBD course is increased susceptibility to infections. In this context, age-of-onset-dependent IBD behavior and clinical course are two major contributors to immune system senescence and change of gut microbiota in older subjects. Here, we review the available literature linking immunosenescence and age-dependent changes in the gut microbiota composition to IBD pathogenesis speculating on their possible implications in disease expression in this age class.

Assessment of small intestinal bacterial overgrowth and methane production in patients on chronic proton-pump inhibitor treatment: prevalence and role of rifaximin in its management in primary care

BACKGROUND

Although proton pump inhibitor (PPI) drugs have considered able to induce small intestinal bacterial overgrowth (SIBO), no data are so far available from primary care (PC). We assessed the prevalence of SIBO and methane (CH4) production consequent to chronic PPI therapy using Lactulose Breath Test (LBT). Secondary aim was to explore the possible role of rifaximin in treating PPI-induced SIBO patients.

METHODS

One hundred twenty-five gastroesophageal reflux disease patients, constantly treated with PPI for at least 6 months and undergoing to LBT, were retrospectively assessed. An age-matched control population (control) of 100 patients, which had not used PPI in the last 6 months, was also enrolled. In the PPI group, SIBO positive patients and CH4 producers were treated with rifaximin 1200 mg/daily for 14 days and re-checked with LBT one month after the end of treatment. The area under the curve (AUC) before and after treatment was also calculated for both SIBO positive patients and CH4 producers.

RESULTS

In the PPI group, SIBO prevalence was significantly higher vs. controls (38/125 [30.4%] vs. 27/100 [27%], P<0.05). 77/125 (61.6%) PPI patients were found to be CH4 producers vs. 21/100 (21%) controls (P<0.05). Among SIBO patients in the PPI group, 34 (89.4%) were also CH4 producers vs. 17/27 (63%) controls (P<0.05). After treatment, LBT resulted negative in 15/22 SIBO patients (68.1%) (P<0.05) and in 18/34 CH4 producers (52.9%) (P<0.05). At the AUC analysis, an overall reduction of 54.2% for H2 in SIBO patients and of 47.7% for CH4 was assessed after rifaximin treatment (P<0.05).

CONCLUSIONS

Our data showed that chronic use of PPI could be able to increase the prevalence of SIBO and to shift the intestinal microbial composition towards a CH4-producing flora. rifaximin could represent a useful therapeutical option for PPI-induced SIBO and for modulating CH4-producing flora.

Evaluation of factors associated with trust in telemedicine in patients with inflammatory bowel disease during COVID-19 pandemic: a multicenter cross-sectional survey

OBJECTIVE

Telemedicine (TM) has had a powerful impact in recent years, particularly on managing chronic diseases such as inflammatory bowel disease (IBD). Knowing patients' expectations and concerns is essential to increase their confidence in this mode of medical care.

PATIENTS AND METHODS

We interviewed a large cohort of IBD patients enrolled at two Italian tertiary referral centers to investigate their trust in TM.

RESULTS

A total of 376 patients completed the survey and were included in the study: 293 (77.9%) considered TM valuable for managing their disease, and 307 (85%) wanted to have TM service at their center. However, only 99 patients (26.3%) believed that TM guarantees the same level of care as the in-person visit. Among the socio-demographic variables, those independently associated with trust in TM were the higher education qualification (p=0.02) and the level of competence in information and communication technologies (ICT) (p=0.03).

CONCLUSIONS

Our findings highlighted the importance of equipping IBD patients with basic ICT skills to utilize TM services and increase their confidence in ICT with the help of caregivers. Additionally, to improve the perceived value of TM, it will be helpful to use additional tools such as telemonitoring of disease activity using patients' reported outcomes or remote measurement of fecal calprotectin.

Comparison of performances of infliximab biosimilars CT-P13 versus SB2 in the treatment of inflammatory bowel diseases: a real-life multicenter, observational study in Italy

BACKGROUND

To compare the performances of Infliximab (IFX) biosimilar CT-P13 and SB2 in the treatment of Inflammatory Bowel Diseases (IBD) outpatients in Italy.

RESEARCH DESIGN AND METHODS

Three hundred and eighty IBD outpatients were retrospectively evaluated. The primary endpoint was to compare the two IFX biosimilars in terms of reaching and maintenance of remission at any timepoint.

RESULTS

197 patients with Ulcerative Colitis (UC) and 183 patients with Crohn's Disease (CD) treated with CT-P13 or SB2 and having a median (IQR) follow-up of 12 (6-36) months were compared: 230 (60.5%) were naïve to anti-TNFα, 20 (5.26%) were switched from IFX originator or from IFX CT-P13 to IFX SB2. Clinical remission was achieved in 133 (67.5%) UC patients and in 164 (89.6%) CD patients (p < 0.000), with no differences between CT-P13 and SB2 in the rate of remission in UC (p = 0.667) and CD (p = 0.286). Clinical response, steroid-free remission, rate of surgery, mucosal healing (MH) in UC, switching from IFX originator or from other biosimilar, and safety were similar. Higher MH rate was obtained in CD patients treated with CT-P13 (p = 0.004).

CONCLUSION

This first comparative study found that both IFX biosimilars CT-P13 and SB2 are effective and safe in managing IBD outpatients.

Changes in admissions, and hospitalization outcomes of IBD patients in an Italian tertiary referral center over a 13-year period

OBJECTIVE

The management of Inflammatory Bowel Disease (IBD) has changed significantly in recent years, mainly due to the introduction of biologic medications, however, other factors may also have a role. The aim of this study was to evaluate the evolution of IBD admissions, including trends, modality of admission and rates of surgical intervention, in a tertiary care center.

PATIENTS AND METHODS

Hospitalization of patients with a diagnosis of Crohn's disease (CD) or ulcerative colitis (UC) were identified between 2000 and 2013, using ICD-9-CM codes for IBD, from our hospital database. The following parameters were evaluated for each admission: type of admission (ordinary vs. day care service), mode of admission (elective vs. emergency care, for ordinary admissions only), admission code, surgical procedures and complication rates. Comparison between pre- and post-biologic therapy introduction years was also performed.

RESULTS

Between 2000 and 2013 a total of 8834 IBD-related admissions were recorded. Hospitalizations increased linearly reaching a peak in 2006, with a downward trend in the following years. The downward trend was especially marked for patients younger than 40 years. No significant differences in hospitalization trends between CD and UC were recorded. Disease flare represented the cause of hospitalization in approximately 50% of cases. Overall, 10.8% of patients underwent surgery with no difference between the two conditions. Complications occurred in 28.7% of admissions.

CONCLUSIONS

Hospitalizations for IBD patients have decreased in recent years, especially in younger patients. However, a significant proportion of patients are still admitted to complete diagnostic workup, indicating the need to better implement outpatient services. A clear reduction in surgery occurrence over time could not be observed in our study.

Akkermansia muciniphila: key player in metabolic and gastrointestinal disorders

OBJECTIVE

Gut microbiota has a key role in host metabolic regulation and immune response, and its dysbiosis represents one of the main causes of gastrointestinal diseases. In this scenario, Akkermansia muciniphila is a crucial player in keeping the integrity of the gastrointestinal tract.

MATERIALS AND METHODS

This review focuses on the correlation between gut microbiota and intestinal homeostasis, primarily exploring A. muciniphila and its involvement in the development of metabolic disorders and gastrointestinal diseases.

RESULTS

Akkermansia muciniphila belongs to the Verrucomicrobia phylum, and it colonizes the mucus layer in the gastrointestinal tract, representing 1 to 4% of the fecal microbiota. It stimulates mucosal microbial networks, and it improves intestinal barrier function, providing crucial host immunological responses. Several studies have demonstrated the possible involvement of A. muciniphila in the development of intestinal and metabolic disorders. Indeed, adipose and glucose metabolisms are influenced by A. muciniphila, and its levels inversely correlate to inflammatory conditions, such as inflammatory bowel disease, obesity, and diabetes. Conversely, its therapeutic administration decreases their development.

CONCLUSIONS

A. muciniphila exerts a key role in the maintenance of intestinal health and in host metabolic modulation. Future studies could open new horizons towards its potential therapeutic applications in gastrointestinal and extra-intestinal diseases.

A transition clinic model for inflammatory bowel disease between two tertiary care centers: outcomes and predictive factors

OBJECTIVE

Few models of transition have been proposed for inflammatory bowel disease (IBD). The aim of the present study is to evaluate the feasibility of a transition model and the predictive factors for success/failure.

PATIENTS AND METHODS

Patients with low activity or remission IBD were enrolled. Proposed model: three meetings every four-six weeks: the first one in the pediatric center (Bambino Gesù Children's Hospital); the second one, in the adult center (Foundation Polyclinic University A. Gemelli), with pediatric gastroenterologists; the last one, in the adult center, with adult gastroenterologists only. Questionnaires included anxiety and depression clinical scale, self-efficacy, quality of life, visual-analogic scale (VAS). Transition was considered successful if the three steps were completed.

RESULTS

Twenty patients were enrolled (range 18-25 years; M/F: 12/8; Ulcerative Colitis/Crohn's Disease 10/10); eight accepted the transition program, four delayed the process and eight refused. Patients who completed transition generated higher scores on the resilience scale, better scores on well-being perception, and had lower anxiety scores. Patients who failed transition were mostly women. The perceived utility of the transition program was scored 7.3 on a VAS scale.

CONCLUSIONS

The proposed transition program seems to be feasible. Psychological scores may help in selecting patients and predicting outcomes.

Increased Faecalibacterium abundance is associated with clinical improvement in patients receiving rifaximin treatment

Compositional and functional alterations of the gut microbiota are involved in the pathogenesis of several gastrointestinal diseases. Rifaximin is often used to induce disease remission due to its eubiotic effects on the gut microbiota. To investigate the correlation between changes in the gut microbiota composition and symptoms improvement in patients who present a clinical response to rifaximin treatment. Patients with ulcerative colitis (UC), Crohn's disease (CD), irritable bowel syndrome (IBS) and diverticular disease (DD) undergoing rifaximin treatment for clinical indication were enrolled in the study. Rifaximin was administered at the dose of 1,200 mg/day for 10 days. Faecal samples were collected at baseline and at the end of treatment; clinical improvement was assessed by Mayo score for UC, CD Activity Index (CDAI) for CD, IBS severity scoring system (IBS-SSS) for IBS and global symptomatic score (GSS) for DD. Twenty-five patients were included in the analysis and a clinical improvement was recorded for 10/25 (40%) of them. Microbial alpha diversity showed a slight increase in clinical responders (P=0.271), while it decreased in patients who did not improved (P=0.05). A significant post-treatment increase in Faecalibacterium abundance was observed in patients with a positive response (log₂FC 1.959, P=0.042). Roseburia abundance decreased in both groups, whereas Ruminococcus decreased only in patients who clinically improved. Clinical improvement consequent to rifaximin treatment is associated with an increase in Faecalibacterium abundance. Achieving a positive shift in the gut microbiota composition seems a key event to obtain a clinical benefit from treatment.

Gastrointestinal symptoms and digestive comorbidities in an Italian cohort of patients with COVID-19

OBJECTIVE

The Coronavirus Disease 2019 (COVID-19) pandemic mainly involves respiratory symptoms, though gastrointestinal (GI) symptoms are increasingly being recognized. In this context, the presence of comorbidities appears to be associated with adverse outcomes. However, the role of digestive manifestations is not yet well defined. The primary aim of this study was to assess the prevalence of GI symptoms and digestive comorbidities in a cohort of patients with COVID-19 compared to controls. The secondary aim was to determine the association of GI-symptoms and digestive comorbidities with clinical outcomes.

PATIENTS AND METHODS

Inpatients with COVID-19 and controls with similar symptoms and/or radiological findings were enrolled. Symptoms at admission and throughout hospitalization were collected as they were comorbidities. The measured clinical outcomes were mortality, intensive care unit admission and cumulative endpoint.

RESULTS

A total of 105 patients were included: 34 with COVID-19 and 71 controls. At admission, the prevalence of GI symptoms among COVID-19 patients was 8.8%. During hospitalization, the frequency of GI symptoms was higher in patients with COVID-19 than in controls (p=0.004). Among patients with COVID-19, the mortality and a cumulative endpoint rates of those with GI symptoms were both lower than for those without GI symptoms (p=0.016 and p=0.000, respectively). Finally, we found digestive comorbidities to be associated with a milder course of COVID-19 (p=0.039 for cumulative endpoint).

CONCLUSIONS

Our results highlighted the non-negligible frequency of GI symptoms in patients with COVID-19, partly attributable to the therapies implemented. In addition, the presence of GI symptoms and digestive comorbidities is associated with better outcomes. Most likely, digestive comorbidities do not hinder the host's immune response against SARS-COV-2, and the occurrence of GI symptoms might be linked to a faster reduction of the viral load via the faecal route.

Intestinal permeability in physiological and pathological conditions: major determinants and assessment modalities

Intestinal permeability is the property that allows solute and fluid exchange between intestinal lumen and intestinal mucosa. Many factors could have major impact on its regulation, including gut microbiota, mucus layer, epithelial cell integrity, epithelial junction, immune responses, intestinal vasculature, and intestinal motility. Any change among these factors could have an impact on intestinal homeostasis and gut permeability. Healthy condition is associated to normal intestinal permeability whereas several intestinal and extra intestinal disease, like inflammatory bowel disease, irritable bowel syndrome, non-alcoholic fatty liver disease among others, are associated to increased intestinal permeability. This review aims to synthesize determinants on intestinal permeability and to report methodologies useful to the measurement of intestinal permeability in clinical practice as well as in research settings.

Gut microbiota compositional and functional fingerprint in patients with alcohol use disorder and alcohol-associated liver disease

BACKGROUND & AIMS

Alcohol use disorder (AUD) represents the most common cause of liver disease. The gut microbiota plays a critical role in the progression of alcohol-related liver damage. Aim of this study was to characterize the gut microbial composition and function in AUD patients with alcohol-associated liver disease (AALD).

METHODS

This study included 36 AUD patients (14 with cirrhosis) who were active drinkers and an equal number of matched controls. Stool microbial composition, serum levels of lipopolysaccharide, cytokines/chemokines and gut microbiota functional profile were assessed.

RESULTS

AUD patients had a decreased microbial alpha diversity as compared to controls (0.092 vs 0.130, P = .047) and a specific gut microbial signature. The reduction of Akkermansia and the increase in Bacteroides were able to identify AUD patients with an accuracy of 93.4%. Serum levels of lipopolysaccharide (4.91 vs 2.43, P = .009) and pro-inflammatory mediators (tumour necrosis factor alpha 60.85 vs 15.08, P = .001; interleukin [IL] 1beta 4.43 vs 1.72, P = .0001; monocyte chemoattractant protein 1 225.22 vs 16.43, P = .006; IL6 1.87 vs 1.23, P = .008) were significantly increased in AUD patients compared to controls and in cirrhotic patients compared to non-cirrhotic ones (IL6 3.74 vs 1.39, P = .019; IL8 57.60 vs 6.53, P = .004). The AUD-associated gut microbiota showed an increased expression of gamma-aminobutyric acid (GABA) metabolic pathways and energy metabolism.

CONCLUSIONS

AUD patients present a specific gut microbial fingerprint, associated with increased endotoxaemia, systemic inflammatory status and functional alterations that may be involved in the progression of the AALD and in the pathogenesis of AUD.

Fecal transplantation for ulcerative colitis: current evidence and future applications

Introduction: Established evidence suggests that gut microbiota plays a role in ulcerative colitis (UC). Fecal microbiota transplantation (FMT) is clearly recognized as a highly effective treatment for patients with recurrent Clostridium difficile infection and has been investigated also in patients with UC, with promising results.Areas covered: Literature review was performed to select publications concerning current evidence on the role of gut microbiota in the pathogenesis of UC, and on the effectiveness of FMT in this disorder.Expert opinion: The randomized controlled trials published investigating the use of FMT suggested a potential role for FMT in the treatment of mild to moderate UC. However, given several unanswered questions regarding donor selection, dose, route of administration and duration of therapy, this is not yet recommended as a viable therapy option. FMT has allowed for more in depth investigation with regards to the role the gut microbiota may be playing in UC. This knowledge is critical to identifying where FMT may appropriately fit in the UC treatment paradigm. As our understanding of the role the microbiome plays in this chronic disease, FMT, and then eventually defined microbes, will hopefully serve in a complementary role to conventional IBD therapies.

Prevalence of cervical HPV and attitude towards cervical screening in IBD patients under immunomodulatory treatment: a multidisciplinary management experience

OBJECTIVE

Therapeutic strategies for Inflammatory Bowel Diseases (IBD: Crohn's disease and Ulcerative Colitis) have improved but the risk for HPV infection in patients under immunomodulatory/biologic treatment is unclear. Objective of the study is to identify the attitude of patients and caregivers to cervical screening. To determine the prevalence of HPV and cervical lesions in IBD patients receiving immunomodulatory/biological treatment.

PATIENTS AND METHODS

IBD patients treated with immunomodulators were enrolled from November 2016 to September 2017, thanks to a multidisciplinary cooperation. A survey was administered to enrolled patients as well as to a selected network of IBD expert physicians. Patients who consented underwent gynecological examination, smear, HPV DNA test, colposcopy, vaginal and cervical microbiological swabs.

RESULTS

294 patients from AMICI Onlus Association, 119 patients from the hospital clinic, 30 doctors from national IBD centers participated to the survey. 19 patients from the IBD clinic underwent cervical screening. More than 90% of doctors consider their patients at risk of cervical cancer. A low prevalence of high-risk genotypes and related HPV lesions and an increased prevalence of bacterial vaginosis emerged in the studied population.

CONCLUSIONS

Biological drugs could lead to a positive immunomodulation towards HPV infection. In IBD patients an alteration of the vaginal and intestinal microbiota seems to be coexisting.

Anti-tumor necrosis factor α therapy associates to type 17 helper T lymphocytes immunological shift and significant microbial changes in dextran sodium sulphate colitis

BACKGROUND

Anti-tumor necrosis factor α (TNFα) represents the best therapeutic option to induce mucosal healing and clinical remission in patients with moderate-severe ulcerative colitis. On the other side gut microbiota plays a crucial role in pathogenesis of ulcerative colitis but few information exists on how microbiota changes following anti-TNFα therapy and on microbiota role in mucosal healing.

AIM

To elucidate whether gut microbiota and immune system changes appear following anti TNFα therapy during dextran sulfate sodium (DSS) colitis.

METHODS

Eighty C57BL/6 mice were divided into four groups: “No DSS”, “No DSS + anti-TNFα”, “DSS” and “DSS + anti-TNFα”. “DSS” and “DSS + anti-TNFα” were treated for 5 d with 3% DSS. At day 3, mice whithin “No DSS+anti-TNFα” and “DSS+anti-TNFα” group received 5 mg/kg of an anti-TNFα agent. Forty mice were sacrificed at day 5, forty at day 12, after one week of recovery post DSS. The severity of colitis was assessed by a clinical score (Disease Activity Index), colon length and histology. Bacteria such as Bacteroides, Clostridiaceae, Enterococcaceae and Fecalibacterium prausnitzii (F. prausnitzii) were evaluated by quantitative PCR. Type 1 helper T lymphocytes (Th1), type 17 helper T lymphocytes (Th17) and CD4⁺ regulatory T lymphocytes (Treg) distributions in the mesenteric lymph node (MLN) were studied by flow cytometry.

RESULTS

Bacteria associated with a healthy state (i.e., such as Bacteroides, Clostridiaceae and F. prausnitzii) decreased during colitis and increased in course of anti-TNFα treatment. Conversely, microorganisms belonging to Enterococcaceae genera, which are linked to inflammatory processes, showed an opposite trend. Furthermore, in colitic mice treated with anti-TNFα microbial changes were associated with an initial increase (day 5 of the colitis) in Treg cells and a consequent decrease (day 12 post DSS) in Th1 and Th17 frequency cells. Healthy mice treated with anti-TNFα showed the same histological, microbial and immune features of untreated colitic mice. “No DSS + anti-TNFα” group showed a lymphomononuclear infiltrate both at 5^th and 12^th d at hematoxylin and eosin staining, an increase of in Th1 and Th17 frequency at day 12, an increase of Enterococcaceae at day 5, a decrease of Bacteroides and Clostridiaceae at day 12.

CONCLUSION

Anti-TNFα treatment in experimental model of colitis improves disease activity but it is associated to an increase in Th17 pathway together with gut microbiota alteration.

Dietary Magnesium Alleviates Experimental Murine Colitis Through Upregulation of the Transient Receptor Potential Melastatin 6 Channel

BACKGROUND

Magnesium (Mg) is essential for human health and is absorbed mainly in the intestine. In view of the likely occurrence of an Mg deficit in inflammatory bowel disease (IBD) and the documented role of Mg in modulating inflammation, the present study addresses whether Mg availability can affect the onset and progression of intestinal inflammation.

METHODS

To study the correlation between Mg status and disease activity, we measured magnesemia by atomic absorption spectroscopy in a cohort of IBD patients. The effects of dietary Mg modulation were assessed in a murine model of dextran sodium sulfate (DSS)-induced colitis by monitoring magnesemia, weight, fecal occult blood, diarrhea, colon length, and histology. Expression of the transient receptor potential melastatin (TRPM) 6 channel was assessed by real-time reverse transcription polymerase chain reaction and immunohistochemistry in murine colon tissues. The effect of Mg on epithelial barrier formation/repair was evaluated in human colon cell lines.

RESULTS

Inflammatory bowel disease patients presented with a substantial Mg deficit, and serum Mg levels were inversely correlated with disease activity. In mice, an Mg-deficient diet caused hypomagnesemia and aggravated DSS-induced colitis. Colitis severely compromised intestinal Mg2+ absorption due to mucosal damage and reduction in TRPM6 expression, but Mg supplementation resulted in better restoration of mucosal integrity and channel expression.

CONCLUSIONS

Our results highlight the importance of evaluating and correcting magnesemia in IBD patients. The murine model suggests that Mg supplementation may represent a safe and cost-effective strategy to reduce inflammation and restore normal mucosal function.

Considering gut microbiota disturbance in the management of Helicobacter pylori infection

Helicobacter pylori (Hp) infection produces drastic changes in the gastric microenvironment, which, in turn, influence the gastric microbiota composition and might be correlated with large intestinal microbiota changes. This excellent perturbing actor could trigger important modifications in the homeostatic functions exerted by gut commensals leading to a new gastrointestinal balance. At the same time, the therapeutic strategies used to eradicate Hp can modulate this physiological symbiosis, but can be also conversely affected by its properties. Area covered: The purpose of this review is to explore the reciprocal interplay between Hp infection and gut microbiota and analyze how microbial changes can influence the management of Hp eradication therapies. Expert commentary: While many studies have described Hp-dependent gut microbiota alterations, their clinical implications are only partially clear, as well as the mechanism of actions that sustain these processes. This represents a clear challenge for future research projects that will also need to understand which role is exerted by viruses, parasites, and yeasts.

Randomised clinical trial: faecal microbiota transplantation by colonoscopy plus vancomycin for the treatment of severe refractory Clostridium difficile infection-single versus multiple infusions

BACKGROUND

Faecal microbiota transplantation (FMT) is a highly effective treatment against recurrent Clostridium difficile infection. Far less evidence exists on the efficacy of FMT in treating severe Clostridium difficile infection refractory to antibiotics.

AIM

To compare the efficacy of two FMT-based protocols associated with vancomycin in curing subjects with severe Clostridium difficile infection refractory to antibiotics.

METHODS

Subjects with severe Clostridium difficile infection refractory to antibiotics were randomly assigned to one of the two following treatment arms: (1) FMT-S, including a single faecal infusion via colonoscopy followed by a 14-day vancomycin course, (2) FMT-M, including multiple faecal infusions plus a 14-day vancomycin course. In the FMT-M group, all subjects received at least two infusions, while those with pseudomembranous colitis underwent further infusions until the disappearance of pseudomembranes. The primary outcome was the cure of refractory severe Clostridium difficile infection.

RESULTS

Fifty six subjects, 28 in each treatment arm, were enrolled. Twenty one patients in the FMT-S group and 28 patients in the FMT-M group were cured (75% vs 100%, respectively, both in per protocol and intention-to-treat analyses; P = 0.01). No serious adverse events associated with any of the two treatment protocols were observed.

CONCLUSIONS

A pseudomembrane-driven FMT protocol consisting of multiple faecal infusions and concomitant vancomycin was significantly more effective than a single faecal transplant followed by vancomycin in curing severe Clostridium difficile infection refractory to antibiotics. Clinical-Trials.gov registration number: NCT03427229.

Gut Microbiota Profiling and Gut-Brain Crosstalk in Children Affected by Pediatric Acute-Onset Neuropsychiatric Syndrome and Pediatric Autoimmune Neuropsychiatric Disorders Associated With Streptococcal Infections

Pediatric acute-onset neuropsychiatric syndrome (PANS) and pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections syndrome (PANDAS) are conditions that impair brain normal neurologic function, resulting in the sudden onset of tics, obsessive-compulsive disorder, and other behavioral symptoms. Recent studies have emphasized the crosstalk between gut and brain, highlighting how gut composition can influence behavior and brain functions. Thus, the present study investigates the relationship between PANS/PANDAS and gut microbiota ecology. The gut composition of a cohort of 30 patients with PANS/PANDAS was analyzed and compared to control subjects using 16S rRNA-based metagenomics. Data were analyzed for their α- and β-diversity; differences in bacterial distribution were detected by Wilcoxon and LEfSe tests, while metabolic profile was predicted via PICRUSt software. These analyses demonstrate the presence of an altered bacterial community structure in PANS/PANDAS patients with respect to controls. In particular, ecological analysis revealed the presence of two main clusters of subjects based on age range. Thus, to avoid age bias, data from patients and controls were split into two groups: 4-8 years old and >9 years old. The younger PANS/PANDAS group was characterized by a strong increase in Bacteroidetes; in particular, Bacteroides, Odoribacter, and Oscillospira were identified as potential microbial biomarkers of this composition type. Moreover, this group exhibited an increase of several pathways concerning the modulation of the antibody response to inflammation within the gut as well as a decrease in pathways involved in brain function (i.e., SCFA, D-alanine and tyrosine metabolism, and the dopamine pathway). The older group of patients displayed a less uniform bacterial profile, thus impairing the identification of distinct biomarkers. Finally, Pearson's analysis between bacteria and anti-streptolysin O titer reveled a negative correlation between genera belonging to Firmicutes phylum and anti-streptolysin O while a positive correlation was observed with Odoribacter. In conclusion, this study suggests that streptococcal infections alter gut bacterial communities leading to a pro-inflammatory status through the selection of specific bacterial strains associated with gut inflammation and immune response activation. These findings highlight the possibility of studying bacterial biomarkers associated with this disorder and might led to novel potential therapeutic strategies.

A novel model of colitis-associated cancer in SAMP1/YitFc mice with Crohn's disease-like ileitis

Patients with inflammatory bowel disease (IBD) are at increased risk for developing colorectal cancer. Evidence suggests that colonic dysplasia and colitis-associated cancer (CAC) are often linked to repeated cycles of epithelial cell injury and repair in the context of chronic production of inflammatory cytokines. Several mouse models of CAC have been proposed, including chemical induction through exposure to dextran sulfate sodium (DSS) with the genotoxic agents azoxymethane (AOM), 1,2-dymethylhydrazine (DHM) or targeted genetic mutations. However, such models are usually performed on healthy animals that usually lack the underlying genetic predisposition, immunological dysfunction and dysbiosis characteristic of IBD. We have previously shown that inbred SAMP1/YitFc (SAMP) mice develop a progressive Crohn’s disease (CD)-like ileitis in the absence of spontaneous colitis. We hypothesize that SAMP mice may be more susceptible to colonic tumorigenesis due to their predisposition to IBD. To test this hypothesis, we administered AOM/DSS to IBD-prone SAMP and their non-inflamed parental control strain, AKR mice. Our results showed that AOM/DSS treatment enhanced the susceptibility of colitis in SAMP compared to AKR mice, as assessed by endoscopic and histologic inflammatory scores, daily weight loss and disease activity index (DAI), during and after DSS administration. SAMP mice also showed increased colonic tumorigenesis, resulting in the occurrence of intramucosal carcinoma and a higher incidence of high-grade dysplasia and tumor burden. These phenomena occurred even in the absence of AOM and only upon repeated cycles of DSS. Taken together, our data demonstrate a heightened susceptibility to colonic inflammation and tumorigenesis in AOM/DSS-treated SAMP mice with CD-like ileitis. This novel model represents a useful tool to investigate relevant mechanisms of CAC, as well as for pre-clinical testing of potential IBD and colon cancer therapeutics.

Gut microbiota and inflammatory bowel disease: so far so gut!

Major advances have occurred in the knowledge of the pathogenesis of inflammatory bowel disease (IBD) over the last decade, and perhaps the most major, and clinically advantageous of these advances has been the discovery of the microbiome as a key multifaceted component of inflammation. The gut microbiome is the largest known group of cells in the body, and is now recognized as an organ in its own right. Initial studies looking at a possible role of bacterial manipulation of the immune system in IBD, looked at identifying a specific bacterial species, and were not representative of a feasible model of inflammation in IBD overall. More recently there has been a shift towards the concept of dysbiosis, and the acceptance that a number of bacterial factors interact with the immune system in order for inflammation to occur. In the present review we will focus on past perspective of the role of microbiota in IBD, current evidences about dysbiosis in IBD and also the main therapeutic modalities to affect IBD by affecting gut microbiota: probiotics, prebiotics, fecal microbiota transplantation and emerging dietary intervention.

Efficacy and Mechanisms of Action of Fecal Microbiota Transplantation in Ulcerative Colitis: Pitfalls and Promises From a First Meta-Analysis

BACKGROUND

Inflammatory bowel disease (IBD) is the results of a chronic inflammatory process deriving from disequilibrium between self-microbiota composition and immune response.

METHODS

New evidence, coming from Clostridium difficile infection, clearly showed that active and powerful modulation of microbiota composition by fecal microbiota composition (FMT) is safe, easy to perform, and efficacious, opening new frontiers in gastrointestinal and extra-intestinal diseases. FMT has been proposed also for IBD as well as other non-gastrointestinal conditions related to intestinal microbiota dysfunctions, with good preliminary data.

RESULTS

In this setting, ulcerative colitis (UC) represents one of the most robust potential indications for FMT after C difficile colitis.

CONCLUSIONS

In the present review, we focus on FMT and its application on ulcerative colitis, clarifying mechanisms of actions and efficacy data, trough completion of a meta-analysis on available randomized, controlled trial data in UC. Because microbiota is so crucially involved in this topic, a short review of microbial alterations in UC will also be performed.

Infliximab does not increase colonic cancer risk associated to murine chronic colitis

AIM

To explore the influence of Infliximab (IFX) on cancer progression in a murine model of colonic cancer associated to chronic colitis.

METHODS

AOM/DSS model was induced in C57BL/6 mice. Mice were injected with IFX (5 mg/kg) during each DSS cycle while control mice received saline. Body weight, occult blood test and stool consistency were measured to calculate the disease activity index (DAI). Mice were sacrificed at week 10 and colons were analyzed macroscopically and microscopically for number of cancers and degree of inflammation. MTT assay was performed on CT26 to evaluate the potential IFX role on metabolic activity and proliferation. Cells were incubated with TNF-α or IFX or TNF-α plus IFX, and cell vitality was evaluated after 6, 24 and 48 h. The same setting was used after pre-incubation with TNF-α for 24 h.

RESULTS

IFX significantly reduced DAI and body weight loss in mice compared with controls, preserving also colon length at sacrifice. Histological score was also reduced in treated mice. At macroscopic analysis, IFX treated mice showed a lower number of tumor lesions compared to controls. This was confirmed at microscopic analysis, although differences were not statistically significant. In vitro, IFX treated CT26 maintained similar proliferation ability at MTT test, both when exposed to IFX alone and when associated to TNF-α.

CONCLUSION

IFX did not increase colonic cancer risk in AOM-DSS model of cancer on chronic colitis nor influence directly the proliferation of murine colon cancer epithelial cells.

Epidemiological evaluation of acute gastroenteritis and therapeutic approaches in Middle East Countries

OBJECTIVE

Gastroenteritis represents with respiratory tract infection the most common infectious disease syndrome of humans in developing countries. Gut microbiota regional variation and dysbiosis play a crucial role in triggering and worsening this devastating GI disease.

MATERIALS AND METHODS

With this manuscript, we want to explore and emphasize the critical aspect of acute gastroenteritis in Middle-East Countries and its correlation with the clinical aspect of gut microbiota modification and intestinal homeostasis.

RESULTS

Approximately 1 of 50 children born each year in developed nations is hospitalized for acute gastroenteritis sometime during childhood. The highest rate of illness occurs in children between 3 and 24 months of age. The common causes of diarrhea are infections with viruses and bacteria, diarrhea due to a systemic infection other than gastrointestinal, diarrhea associated with antibiotic administration, and feeding related diarrhea. The single most common diarrheal disorder observed in the Emergency Department and general practice is viral gastroenteritis. In particular, Rotavirus is the cause of more than 2 million hospitalizations and over half a million deaths from acute GE in infants and young children. This burden produces also direct and indirect economic costs. The use of probiotics to counterbalance commensal dysbiosis is emerging as a standard medical practice in these countries.

CONCLUSIONS

In this scenario, one of the most interesting aspects is that probiotics and gut microbiota modulation could deeply improve the prevention and treatment of this devastating GI pathology. At the same time, vaccination might represent a cost-effective strategy to reduce the health and economic burden of some pathogens, such as rotavirus.

Bacillus clausii and gut homeostasis: state of the art and future perspectives

INTRODUCTION

The intestinal barrier is a complex system responsible for the host health. Many gastrointestinal and extra-intestinal diseases are associated to gut barrier disruption. An increasing interest on nutritional supplements and functional foods focused on the hypothesis that specific prebiotics and probiotics may modulate and interact with gut barrier, re-establishing gut homeostasis.

AREAS COVERED

The application of preparations containing B. clausii in the treatment or prevention of gut phisiology impairment has been largely supported in the last years and has driven its clinical applications. This review focuses on B. clausii clinical applications and speculates on the possible interactions among B. clausii, gut barrier and immune system and on the consequences of this interplay in modulating human health. Expert commentary: Its favorable effects have been linked to several properties, such as antimicrobial and immunomodulatory activity, regulation of cell growth and differentiation, cell-cell signaling, cell adhesion, signal transcription and transduction, production of vitamins and gut protection from genotoxic agents. In this scenario, future studies will need to better clarify its mechanisms of action and focus on the possible role of B. clausii in modulating gut immune system.

Gut Microbiota: A Key Modulator of Intestinal Healing in Inflammatory Bowel Disease

Mucosal healing (MH) represents a crucial factor for maintaining gut homeostasis. Indeed, in inflammatory bowel disease, MH has become the standard therapeutical target, because it is associated with more effective disease control, more frequent steroid-free remission, lower rates of hospitalization and surgery, and improved quality of life. In this scenario, gut microbiota is a crucial player in modulating intestinal repair and regeneration process. It can act on the tumor necrosis factor-α production, modulation of reactive oxygen and nitrogen species, activity of matrix metalloproteinases and on many other mechanisms strictly involved in restoring gut health. In this review, we analyze and review the literature on the role of gut microbiota in sustaining mucosal injury and achieving MH.

The Role of Antibiotics in Gut Microbiota Modulation: The Eubiotic Effects of Rifaximin

Antibiotics are mainly used in clinical practice for their activity against pathogens, but they also alter the composition of commensal gut microbial community. Rifaximin is a non-absorbable antibiotic with additional effects on the gut microbiota about which very little is known. It is still not clear to what extent rifaximin can be able to modulate gut microbiota composition and diversity in different clinical settings. Studies based on culture-dependent techniques revealed that rifaximin treatment promotes the growth of beneficial bacteria, such as Bifidobacteria and Lactobacilli. Accordingly, our metagenomic analysis carried out on patients with different gastrointestinal and liver diseases highlighted a significant increase in Lactobacilli after rifaximin treatment, persisting in the short time period. This result was independent of the disease background and was not accompanied by a significant alteration of the overall gut microbial ecology. This suggests that rifaximin can exert important eubiotic effects independently of the original disease, producing a favorable gut microbiota perturbation without changing its overall composition and diversity.

High dose amoxicillin-based first line regimen is equivalent to sequential therapy in the eradication of H. pylori infection

OBJECTIVE

Helicobater (H.) pylori eradication rates with standard first-line triple therapy have declined to unacceptable levels. To date, amoxicillin-resistant H. pylori strains have rarely been detected. Whether increasing the dosage of amoxicillin in a standard 7 days eradicating regimen may enhance its efficacy is not known. The aim of this paper is to compare the efficacy of a 7 days high-dose amoxicillin based first-line regimen with sequential therapy.

PATIENTS AND METHODS

We have retrospectively analyzed data from 300 sex and age matched patients, who underwent 3 different therapeutic schemes: (1) standard LCA, lansoprazole 30 mg bid, clarithromycin 500 mg bid and amoxicillin 1000 mg bid for 7 days; (2) high dose LCA (HD-LCA), lansoprazole 30 mg bid, clarithromycin 500 mg bid and amoxicillin 1000 mg tid for 7 days; (3) sequential LACT, lansoprazole 30 mg bid plus amoxicillin 1000 mg bid for 5 days, followed by lansoprazole 30 mg bid, clarithromycin 500 mg bid and tinidazole 500 mg bid for 5 days. Eradication was confirmed by 13C-urea breath test. Compliance and occurrence of adverse effects were also assessed.

RESULTS

Eradication rates were: 55% for LCA, 75% for HD-LCA and 73% for LACT. Eradication rates were higher in HD-LCA group compared to LCA (p<0.01), while no significant differences were observed in HD-LCA group compared to LACT (p=ns). Compliance and occurrence of adverse effects were similar among groups.

CONCLUSIONS

High-dose amoxicillin based eradicating treatment is superior to standard triple therapy and equivalent to sequential therapy; compared to the latter, the shorter duration may represent an advantage.

The therapeutic management of gut barrier leaking: the emerging role for mucosal barrier protectors

OBJECTIVE

Gut barrier is a functional unit organized as a multi-layer system and its multiple functions are crucial for maintaining gut homeostasis. Numerous scientific evidences showed a significant association between gut barrier leaking and gastro-intestinal/extra-intestinal diseases.

MATERIALS AND METHODS

In this review we focus on the relationship between gut barrier leaking and human health. At the same time we speculate on the possible new role of gut barrier protectors in enhancing and restoring gut barrier physiology with the final goal of promoting gut health.

RESULTS

The alteration of the equilibrium in gut barrier leads to the passage of the luminal contents to the underlying tissues and thus into the bloodstream, resulting in the activation of the immune response and in the induction of gut inflammation. This permeability alteration is the basis for the pathogenesis of many diseases, including infectious enterocolitis, inflammatory bowel diseases, irritable bowel syndrome, small intestinal bacterial overgrowth, celiac disease, hepatic fibrosis, food intolerances and also atopic manifestations. Many drugs or compounds used in the treatment of gastrointestinal disease are able to alter the permeability of the intestinal barrier. Recent data highlighted and introduced the possibility of using gelatin tannate, a mucosal barrier protector, for an innovative approach in the management of intestinal diseases, allowing an original therapeutic orientation with the aim of enhancing mucus barrier activity and restoring gut barrier.

CONCLUSIONS

These results suggest how the mucus layer recovering, beside the gut microbiota modulation, exerted by gut barrier protectors could be a useful weapon to re-establish the physiological intestinal homeostasis after an acute and chronic injury.

The gastrointestinal microbiome - functional interference between stomach and intestine

The gastrointestinal (GI) tract is a complex and dynamic network with interplay between various gut mucosal cells and their defence molecules, the immune system, food particles, and the resident microbiota. This ecosystem acts as a functional unit organized as a semipermeable multi-layer system that allows the absorption of nutrients and macromolecules required for human metabolic processes and, on the other hand, protects the individual from potentially invasive microorganisms. Commensal microbiota and the host are a unique entity in a continuum along the GI tract, every change in one of these players is able to modify the whole homeostasis. In the stomach, Helicobacter pylori is a gram-negative pathogen that is widespread all over the world, infecting more than 50% of the world's population. In this scenario, H. pylori infection is associated with changes in the gastric microenvironment, which in turn affects the gastric microbiota composition, but also might trigger large intestinal microbiota changes. It is able to influence all the vital pathways of human system and also to influence microbiota composition along the GI tract. This can cause a change in the normal functions exerted by intestinal commensal microorganisms leading to a new gastrointestinal physiological balance. This review focuses and speculates on the possible interactions between gastric microorganisms and intestinal microbiota and on the consequences of this interplay in modulating gut health.

Opposing Functions of Classic and Novel IL-1 Family Members in Gut Health and Disease

In addition to their well-established role(s) in the pathogenesis of gastrointestinal (GI)-related inflammatory disorders, including inflammatory bowel disease (IBD) and inflammation-associated colorectal cancer (CRC), emerging evidence confirms the critical involvement of the interleukin-1 (IL-1) cytokine family and their ligands in the maintenance of normal gut homeostasis. In fact, the paradigm that IBD occurs in two distinct phases is substantiated by the observation that classic IL-1 family members, such as IL-1, the IL-1 receptor antagonist (IL-1Ra), and IL-18, possess dichotomous functions depending on the phase of disease, as well as on their role in initiating vs. sustaining chronic gut inflammation. Another recently characterized IL-1 family member, IL-33, also possesses dual functions in the gut. IL-33 is upregulated in IBD and potently induces Th2 immune responses, while also amplifying Th1-mediated inflammation. Neutralization studies in acute colitis models, however, have yielded controversial results and recent reports suggest a protective role of IL-33 in epithelial regeneration and mucosal wound healing. Finally, although little is currently known regarding the potential contribution of IL-36 family members in GI inflammation/homeostasis, another IL-1 family member, IL-37, is emerging as a potent anti-inflammatory cytokine with the ability to down-regulate colitis. This new body of information has important translational implications for both the prevention and treatment of patients suffering from IBD and inflammation-associated CRC.

13C-octanoic acid breath test to study gastric emptying time

Digestion is a complex process regulated by several factors. Among these, one of the most important is the time of gastric emptying. A delayed gastric emptying time can be caused by several factors and can generate considerable discomfort in humans. It ranges from mild to real debilitating disorders. Until now, different tests are suggested to study the gastric emptying time. The present review presents the mayor cause and the main symptoms linked to delayed gastric emptying and will focus on the (13)C-octanoid acid breath test, as a good candidate for studying solid gastric emptying time.

Intestinal gas production and gastrointestinal symptoms: from pathogenesis to clinical implication

Intestinal gases are the expression of metabolic activity of gut microbiota in the gut, particularly carbohydrates in the case of H2, CH4. Alterations in composition of gases and air handling, directly or upon challenge with food are relevant for GI and extra-GI diseases. Assessing gas composition in breath can be a very useful tool for clinic, but technical issues are crucial (breath sampling, storing and analyzing). Aim of the present review is to summarize the understanding of the importance of intestinal gases in gastro-intestinal physiology and patho-physiology. Practical considerations on how to collect samples and instruments available for the clinic have also been provided.

Specific 13C functional pathways as diagnostic targets in gastroenterology breath-tests: tricks for a correct interpretation

Breath tests are non-invasive, non-radioactive, safe, simple and effective tests able to determine significant metabolic alterations due to specific diseases or lack of specific enzymes. Carbon isotope (13)C, the stable-non radioactive isotope of carbon, is the most used substrate in breath testing, in which (13)C/(12)C ratio is measured and expressed as a delta value, a differences between readings and a fixed standard. (13)C/(12)C ratio is measured with isotope ratio mass spectrometry or non-dispersive isotope-selective infrared spectrometer and generally there is a good agreement between these techniques in the isotope ratio estimation. (13)C/(12)C ratio can be expressed as static measurement (like delta over baseline in urea breath test) or as dynamic measurement as percent dose recovery, but more dosages are necessary. (13)C Breath-tests are involved in many fields of interest within gastroenterology, such as detection of Helicobacter pylori infection, study of gastric emptying, assessment of liver and exocrine pancreatic functions, determination of oro-caecal transit time, evaluation of absorption and to a lesser extend detection of bacterial overgrowth. The use of every single test in a clinical setting is vary depending on accuracy and substrate costs. This review is meant to present (13)C the meaning of (13)C/(12)C ratio and static and dynamic measure and, finally, the instruments dedicated to its use in gastroenterology. A brief presentation of (13)C breath tests in gastroenterology is also provided.

Tricks for interpreting and making a good report on hydrogen and 13C breath tests

Breath tests (BT) represent a valid and non-invasive diagnostic tool in many gastroenterological disorders. Their wide diffusion is due to the low cost, simplicity and reproducibility and their common indications include diagnosis of carbohydrate malabsorption, Helicobacter pylori infection, small bowel bacterial overgrowth, gastric emptying time and orocaecal transit time. The review deals with key points on methodology, which would influence the correct interpretation of the test and on a correct report. While a clear guideline is available for lactose and glucose breath tests, no gold standard is available for Sorbitol, Fructose or other H2 BTs. Orocaecal transit time (OCTT) defined as time between assumption of 10 g lactulose and a peak > 10 ppm over the baseline value, is a well-defined breath test. The possible value of lactulose as a diagnostic test for the diagnosis of small bowel bacterial overgrowth is still under debate. Among (13)C breath test, the best and well characterized is represented by the urea breath test. Well-defined protocols are available also for other (13)C tests, although a reimbursement for these tests is still not available. Critical points in breath testing include the patient preparation for test, type of substrate utilized, reading machines, time between when the test is performed and when the test is processed. Another crucial point involves clinical conclusions coming from each test. For example, even if lactulose could be utilized for diagnosing small bowel bacterial overgrowth, this indication should be only secondary to orocaecal transit time, and added into notes, as clinical guidelines are still uncertain.

Emerging role of the interleukin (IL)-33/ST2 axis in gut mucosal wound healing and fibrosis

Interleukin (IL)-33 (IL-1F11) is the newest member of the IL-1Family of cytokines and has been best characterized as a potent inducer of T helper (Th)2 immune responses. Increasing evidence, however, indicates that IL-33 also represents an important mediator of mucosal healing and epithelial restoration and repair. As such, IL-33 follows the trend of several innate-type cytokines, including members of the IL-1Family (for example, IL-1α, IL-1β, and IL-18), that possess dichotomous roles of inducing a potent proinflammatory response, while also promoting protection and the return to immune homeostasis. This dual function is best depicted in the gut mucosa and is dependent upon the immunological/genetic status of the host and/or the type and phase of the ongoing inflammatory process. IL-33 has also been described as a prototypic 'alarmin' that has the ability to signal local, innate immune responses of trauma or infection in an effort to mount an effective, physiologic inflammatory reaction to induce mucosal healing and restore normal gut equilibrium. Finally, several recent studies have reported the role of IL-33 during fibrogenesis as fibrosis is commonly thought to occur as the end stage of dysregulated wound healing wherein chronic tissue damage is paired with uncontrolled activation of mesenchymal cells. Taken together, aside from its established function of promoting potent Th2 immune responses, IL-33 is emerging as an important cytokine for the induction of mucosal healing and restoration of intestinal homeostasis, as well as playing a central role in fibrosis and wound repair. The present review will focus on what is currently known regarding IL-33's role in gut mucosal wound healing and fibrosis, as well as touch on its potential contribution to tumorigenesis and GI-related cancer, an alternate outcome of dysregulated epithelial proliferation.