The Interplay between Immune System and Microbiota in Inflammatory Bowel Disease: A Narrative Review.

The importance of the gut microbiota in human health is currently well established. It contributes to many vital functions such as development of the host immune system, digestion and metabolism, barrier against pathogens or brain-gut communication. Microbial colonization occurs during infancy in parallel with maturation of the host immune system; therefore, an adequate cross-talk between these processes is essential to generating tolerance to gut microbiota early in life, which is crucial to prevent allergic and immune-mediated diseases. Inflammatory bowel disease (IBD) is characterized by an exacerbated immune reaction against intestinal microbiota. Changes in abundance in the gut of certain microorganisms such as bacteria, fungi, viruses, and archaea have been associated with IBD. Microbes that are commonly found in high abundance in healthy gut microbiomes, such as F. prausnitzii or R. hominis, are reduced in IBD patients. E. coli, which is usually present in a healthy gut in very low concentrations, is increased in the gut of IBD patients. Microbial taxa influence the immune system, hence affecting the inflammatory status of the host. This review examines the IBD microbiome profile and presents IBD as a model of dysbiosis.

Lunasin Peptide is a Modulator of the Immune Response in the Human Gastrointestinal Tract.

INTRODUCTION: Lunasin is a soybean bioactive peptide with a variety of beneficial properties against chronic disorders. However, its effect in human primary intestinal cells remains unknown. Hence, this study aims to characterize its ex vivo biological activity in the human intestinal mucosa. METHODS AND RESULTS: Human intestinal biopsies, obtained from healthy controls, are ex vivo conditioned with lunasin both in the presence/absence of lipopolysaccharide (LPS). Peptide maintains its stability during biopsy culture by HPLC-MS/MS analysis. Lunasin is bioactive in the human mucosa, as it induces IL-1ß, TNF-α, IL-17A, CCL2, and PGE2/COX-2 gene expression together with an increased expression of tolerogenic IL-10 and TGFß, while it also downregulates the expression of iNOS and subunit p65 from NF-κB. Indeed, lunasin also abrogates the LPS-induced pro-inflammatory response, downregulating IL-17A, IFNγ, and IL-8 expression, and inducing IL-10 and TGFß expression. These results are also mirrored in the cell-free culture supernatants at the protein level by Multiplex. Moreover, lunasin further induces a regulatory phenotype and function on human intestinal conventional dendritic cell and macrophage subsets as assessed by flow cytometry. CONCLUSIONS: We hereby have characterized lunasin as an immunomodulatory peptide with potential capacity to prevent immune and inflammatory-mediated disorders in the human gastrointestinal tract.

Profiling of Human Circulating Dendritic Cells and Monocyte Subsets Discriminates Between Type and Mucosal Status in Patients With Inflammatory Bowel Disease.

BACKGROUND: Intestinal dendritic cells (DC) and macrophages drive disease progression in patients with inflammatory bowel disease (IBD). We aimed to characterize the activation and homing profile of human circulating DC and monocyte subsets in healthy control patients (CP) and IBD patients. METHODS: Eighteen CP and 64 patients with IBD were categorized by diagnoses of Crohn disease (CD) and ulcerative colitis (UC), either endoscopically active (inflamed) or quiescent. Circulating type 1 conventional DC, type 2 conventional DC, plasmacytoid DC, classical monocytes, nonclassical monocytes, and intermediate monocytes were identified by flow cytometry in each individual and characterized for the expression of 18 markers. Association between DC/monocytes and IBD risk was tested by logistic regression. Discriminant canonical analyses were performed to classify the patients in their own endoscopy category considering all markers on each subset. RESULTS: CCRL1, CCR3, and CCR5 expression on circulating type 1 DC; CCRL1 expression on nonclassical monocytes; and CCR9 and ß7 expression on classical monocytes allowed us to discriminate among the different study groups. Indeed, the same markers (excluding ß7) were also associated with IBD when all DC and monocyte subsets were considered at the same time. CONCLUSIONS: Monitoring the phenotype of human circulating DC and monocyte subsets may provide novel tools as biomarkers for disease diagnosis (CD/UC) or mucosal status (inflamed/noninflamed) in the absence of an invasive colonoscopy.

Fendrix vs Engerix-B for Primo-Vaccination Against Hepatitis B Infection in Patients With Inflammatory Bowel Disease: A Randomized Clinical Trial.

INTRODUCTION: To compare Engerix-B and Fendrix hepatitis B virus for primo vaccination in inflammatory bowel disease (IBD). METHODS: Patients with IBD were randomized 1:1 to receive Engerix-B double dose or Fendrix single dose at months 0, 1, 2, and 6. Anti-HBs titers were measured 2 months after the third and fourth doses. Response to vaccination was defined as anti-HBs ≥100 UI/L. Anti-HBs titers were measured 2 months after the third and fourth doses and again at 6 and 12 months after the fourth dose. RESULTS: A total of 173 patients were randomized (54% received Engerix-B and 46% Fendrix). Overall, 45% of patients responded (anti-HBs ≥100 IU/L) after 3 doses and 71% after the fourth dose. The response rate after the fourth dose was 75% with Fendrix vs 68% with Engerix-B (P = 0.3). Older age and treatment with steroids, immunomodulators, or anti-tumor necrosis factor were associated with a lower probability of response. However, the type of vaccine was not associated with the response. Anti-HBs titer negativization occurred in 13% of patients after 6 months and 20% after 12 months. Anti-HBs ≥100 IU/L after vaccination was the only factor associated with maintaining anti-HBs titers during follow-up. DISCUSSION: We could not demonstrate a higher response rate of Fendrix (single dose) over Engerix-B (double dose). A 4-dose schedule is more effective than a 3-dose regimen. Older age and treatment with immunomodulators or anti-tumor necrosis factors impaired the success. A high proportion of IBD patients with protective anti-HBs titers after vaccination loose them over time. The risk of losing protective anti-HBs titers is increased in patients achieving anti-HBs <100 IU/L after the vaccination.

Serum adipokines as non-invasive biomarkers in Crohn's disease.

Adipose tissue secretes molecules that can promote activity in Crohn's disease. We aimed to evaluate the role of serum adipokines as possible biomarkers in Crohn's disease. Serum samples were obtained from 40 patients with endoscopically active or quiescent Crohn's disease and 36 healthy controls. Serum leptin, ghrelin, resistin and adiponectin levels were analysed by Multiplex in a Luminex 200 system technology. Receiver Operating Characteristic curves were performed to evaluate the adipokines discriminatory capacity. A logistic regression adjusted by possible confounders (i.e. gender, age, BMI) was performed for those adipokines that showed an area under the curve > 0.7. No differences were found in age, gender or BMI among groups. Distribution for serum resistin was different among the three groups of study, and only this adipokine showed an area under the curve of 0.75 comparing actives patients and healthy control groups. Resistin median concentration was selected as a cut-off for a logistic regression analysis; odds ratio along its 95% confidence interval adjusted by gender, age, and BMI yielded a value of 5.46 (1.34-22.14) comparing actives patients and healthy controls. High concentration of serum resistin is probably associated to activity, being this association independent of gender, age or BMI.

A quick flow cytometry protocol to assess Helicobacter pylori viability.

Here we present an easy flow cytometry protocol to study the viability of Helicobacter pylori which also enables the detection of even low live bacteria densities. This protocol has potential utility for a fast and accurate assessment of experimental eradication methods against H. pylori.

Immunomodulatory Effect of Gut Microbiota-Derived Bioactive Peptides on Human Immune System from Healthy Controls and Patients with Inflammatory Bowel Disease.

Bioactive peptides secreted by probiotic Bifidobacterium longum (peptide B7) and opportunistic pathogen Bacteroides fragilis (peptide B12) modulate the intestinal cytokine milieu in health. Here, we characterized their capacity to modulate both the mucosal cytokine production and the phenotype of circulating antigen presenting cells (APCs) in active inflammatory bowel disease (IBD). The IBD mucosa produced higher levels of pro-inflammatory cytokines referred to healthy controls (HCs). Peptides B7 and B12, however, did not ameliorate the mucosal cytokine milieu in IBD. Human circulating APCs (B-cells, monocytes, plasmacytoid dendritic cells (pDCs), and conventional dendritic cells (cDCs)) were characterized by flow cytometry in presence/absence of the peptides. Circulating B-cells, monocytes, and cDCs from IBD patients were more activated than those from HCs. Peptide B7, but not B12, decreased CCR2 expression on all APC subsets from HC, but not IBD patients. Moreover, both peptides tend to further increase their pro-inflammatory profile in IBD. In summary, IBD patients display mucosal and circulating APC pro-inflammatory properties. Peptide B7 immunomodulatory capacity elicited over circulating APCs from HC, but not IBD patients, suggests the presence of disrupted modulatory mechanisms for this peptide in IBD. Future studies should address the effect of bacteria-derived immunomodulatory peptides in non-inflamed (quiescent) IBD patients.

Functional rare variants influence the clinical response to anti-TNF therapy in Crohn's disease.

BACKGROUND: The effect of low-frequency functional variation on anti-tumor necrosis factor alpha (TNF) response in Crohn's disease (CD) patients remains unexplored. The objective of this study was to investigate the impact of functional rare variants in clinical response to anti-TNF therapy in CD. METHODS: CD anti-TNF naïve patients starting anti-TNF treatment due to active disease [Crohn's Disease Activity Index (CDAI > 150)] were included. The whole genome was sequenced using the Illumina Hiseq4000 platform. Clinical response was defined as a CDAI score <150 at week 14 of anti-TNF treatment. Low-frequency variants were annotated and classified according to their damaging potential. The whole genome of CD patients was screened to identify homozygous loss-of-function (LoF) variants. The TNF signaling pathway was tested for overabundance of damaging variants using the SKAT-O method. Functional implication of the associated rare variation was evaluated using cell-type epigenetic enrichment analyses. RESULTS: A total of 41 consecutive CD patients were included; 3250 functional rare variants were identified (2682 damaging and 568 LoF variants). Two homozygous LoF mutations were found in HLA-B and HLA-DRB1 genes associated with lack of response and remission, respectively. Genome-wide LoF variants were enriched in epigenetic marks specific for the gastrointestinal tissue (colon, p = 4.11e-4; duodenum, p = 0.011). The burden of damaging variation in the TNF signaling pathway was associated with response to anti-TNF therapy (p = 0.016); damaging variants were enriched in epigenetic marks from CD8+ (p = 6.01e-4) and CD4+ (p = 0.032) T cells. CONCLUSIONS: Functional rare variants are involved in the response to anti-TNF therapy in CD. Cell-type enrichment analysis suggests that the gut mucosa and CD8+ T cells are the main mediators of this response.

Efficacy and Safety of Quinolone-Containing Rescue Therapies After the Failure of Non-Bismuth Quadruple Treatments for Helicobacter pylori Eradication: Systematic Review and Meta-Analysis.

BACKGROUND: Anti-Helicobacter pylori eradication treatment fails in a significant percentage of cases. Although this percentage has been reduced to 5-15% with the use of non-bismuth quadruple therapies, limited data exist regarding rescue after failure of these treatments. AIM: The aim of this study was to systematically review the efficacy and safety of quinolone-containing therapies after the failure of non-bismuth quadruple regimens. METHODS: Studies evaluating the efficacy of second-line quinolone-containing therapies after the failure of non-bismuth sequential or concomitant regimens were selected. Efficacy (by intention to treat) was analyzed using the inverse variance method; safety data were recorded as the occurrence of any adverse event. The risk of bias of each primary study was evaluated using the Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I) tool. The quality of the evidence was summarized using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach. RESULTS: Sixteen studies were included. The 10-day levofloxacin/amoxicillin/proton pump inhibitor (PPI) triple therapy (LT) achieved eradication rates of 80% (95% CI 71-88). Regarding the moxifloxacin/amoxicillin/PPI triple therapy (MT), its efficacy was higher when administered for 14 days instead of 7 days (80 vs 63%). Two studies investigated the levofloxacin/bismuth-containing quadruple therapies (LBQ) obtaining eradication rates over 90%. Safety was similar in all treatments. The sensitivity analyses showed that results for LT were robust, but MT had weak evidence. CONCLUSIONS: Quinolone-containing triple therapies reported eradication rates ≤80%, but LBQ therapies showed encouraging rates. However, the strength of the evidence was very low. The efficacy of LBQ should be corroborated in more studies, and the usefulness of quinolones needs to be evaluated in areas with moderate to high bacterial resistances.

The Risk of Relapse after Anti-TNF Discontinuation in Inflammatory Bowel Disease: Systematic Review and Meta-Analysis.

OBJECTIVES: To perform a meta-analysis of the risk of relapse after discontinuation of anti-tumor necrosis factor (anti-TNF) therapy in patients with Crohn's disease (CD) and ulcerative colitis (UC), to evaluate risk factors for relapse, and to assess the response to retreatment with the same anti-TNF. METHODS: Studies evaluating the incidence of relapse after anti-TNF discontinuation in patients with CD or UC who reached clinical remission with anti-TNFs were included. Bibliographies up to January 2015 were searched. Frequency of relapse after discontinuation of anti-TNF agents was determined; meta-analyses were performed using the inverse-variance method. RESULTS: We included 27 studies (21 infliximab and 6 infliximab/adalimumab). The overall risk of relapse after discontinuation of anti-TNF therapy was 44% for CD (95% confidence interval (CI) 36-51%; I(2)=79%; 912 patients) and 38% for UC (23-52%; I(2)=82%; 266 patients). In CD, the relapse rate was 38% at 6 months after discontinuation (short term), 40% at 12 months (medium term), and 49% at >25 months (long term). In UC, 28% of patients relapsed at 12 months. In CD, when clinical remission was the only criterion for stopping anti-TNF therapy, the relapse rate after 1 year was 42%, which decreased to 26% when endoscopic remission was also required. Retreatment with the same anti-TNF induced remission again in 80% of cases (68-91%). CONCLUSIONS: Approximately one-third of patients with inflammatory bowel disease in remission under anti-TNF treatment relapsed 1 year after discontinuation. This proportion increased to half in the long term. In CD patients, the risk of relapse was lower when the criterion for discontinuation was endoscopic remission and not only clinical remission. Response to retreatment with the same anti-TNF agent was favorable.

Immunogenicity and mechanisms impairing the response to vaccines in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is an immunological disorder that is usually treated with immunosuppressive therapy, potentially leading to increases in vulnerability to infections. Although many infections can be prevented by vaccination, vaccination coverage in these patients in clinical practice is insufficient. Therefore, the seroprotection condition should be verified, even for routine vaccines, such as hepatitis B or pneumococcus. Response to vaccines in IBD patients is thought to be impaired due to the immunological alterations generated by the disease and to the immunomodulatory treatments. The immunogenicity of hepatitis B, influenza, and pneumococcal vaccines is impaired in IBD patients, whereas the response to papillomavirus vaccine seems similar to that observed in the healthy population. On the other hand, data on the immunogenicity of tetanus vaccine in IBD patients are conflicting. Studies assessing the response to measles-mumps-rubella, varicella, and herpes zoster vaccines in IBD patients are scarce. The cellular and molecular mechanisms responsible for the impairment of the response to vaccination in IBD patients are poorly understood. Studies aiming to assess the response to vaccines in IBD patients and to identify the mechanisms involved in their immunogenicity are warranted. A better understanding of the immune response, specifically to vaccines, in patients with immune-mediated diseases (such as IBD), is crucial when developing vaccines that trigger more potent immunologic responses.

Two-week, high-dose proton pump inhibitor, moxifloxacin triple Helicobacter pylori therapy after failure of standard triple or non-bismuth quadruple treatments.

BACKGROUND: Aim was to evaluate the efficacy and tolerability of a moxifloxacin-containing second-line triple regimen in patients whose previous Helicobacter pylori eradication treatment failed. METHODS: Prospective multicentre study including patients in whom a triple therapy or a non-bismuth-quadruple-therapy failed. Moxifloxacin (400mg qd), amoxicillin (1g bid), and esomeprazole (40 mg bid) were prescribed for 14 days. Eradication was confirmed by (13)C-urea-breath-test. Compliance was determined through questioning and recovery of empty medication envelopes. RESULTS: 250 patients were consecutively included (mean age 48 ± 15 years, 11% with ulcer). Previous (failed) therapy included: standard triple (n = 179), sequential (n = 27), and concomitant (n = 44); 97% of patients took all medications, 4 were lost to follow-up. Intention-to-treat and per-protocol eradication rates were 82.4% (95% CI, 77-87%) and 85.7% (95% CI, 81-90%). Cure rates were similar independently of diagnosis (ulcer, 77%; dyspepsia, 82%) and previous treatment (standard triple, 83%; sequential, 89%; concomitant, 77%). At multivariate analysis, only age was associated with eradication (OR = 0.957; 95% CI, 0.933-0.981). Adverse events were reported in 25.2% of patients: diarrhoea (9.6%), abdominal pain (9.6%), and nausea (9.2%). CONCLUSION: 14-day moxifloxacin-containing triple therapy is an effective and safe second-line strategy in patients whose previous standard triple therapy or non-bismuth quadruple (sequential or concomitant) therapy has failed, providing a simple alternative to bismuth quadruple regimen.

Helicobacter pylori first-line and rescue treatments in the presence of penicillin allergy.

BACKGROUND: Helicobacter pylori eradication is a challenge in penicillin allergy. AIM: To assess the efficacy and safety of first-line and rescue treatments in patients allergic to penicillin. METHODS: Prospective multicenter study. Patients allergic to penicillin were given a first-line treatment comprising (a) 7-day omeprazole-clarithromycin-metronidazole and (b) 10-day omeprazole-bismuth-tetracycline-metronidazole. Rescue treatments were as follows: (a) bismuth quadruple therapy; (b) 10-day PPI-clarithromycin-levofloxacin; and (c) 10-day PPI-clarithromycin-rifabutin. Eradication was confirmed by (13)C-urea breath test. Compliance was determined through questioning and recovery of empty medication envelopes. Adverse effects were evaluated by questionnaires. RESULTS: In total, 267 consecutive treatments were included. (1) First-line treatment: Per-protocol and intention-to-treat eradication rates with omeprazole-clarithromycin-metronidazole were 59 % (62/105; 95 % CI 49-62 %) and 57 % (64/112; 95 % CI 47-67 %). Respective figures for PPI-bismuth-tetracycline-metronidazole were 75 % (37/49; 95 % CI 62-89 %) and 74 % (37/50; 95 % CI (61-87 %) (p < 0.05). Compliance with treatment was 94 and 98 %, respectively. Adverse events were reported in 14 % with both regimens (all mild). (2) Second-line treatment: Intention-to-treat eradication rate with omeprazole-clarithromycin-levofloxacin was 64 % both after triple and quadruple failure; compliance was 88-100 %, with 23-29 % adverse effects (all mild). (3) Third-/fourth-line treatment: Intention-to-treat eradication rate with PPI-clarithromycin-rifabutin was 22 %. CONCLUSION: In allergic to penicillin patients, a first-line treatment with a bismuth-containing quadruple therapy (PPI-bismuth-tetracycline-metronidazole) seems to be a better option than the triple PPI-clarithromycin-metronidazole regimen. A levofloxacin-based regimen (together with a PPI and clarithromycin) represents a second-line rescue option in the presence of penicillin allergy.

Randomised clinical trial comparing sequential and concomitant therapies for Helicobacter pylori eradication in routine clinical practice.

OBJECTIVES: No trial has compared non-bismuth quadruple 'sequential' and 'concomitant' regimens in settings with increasing clarithromycin rates. The study aims to compare the effectiveness and safety of these therapies for Helicobacter pylori treatment. DESIGN: Prospective randomised clinical trial in 11 Spanish hospitals. Patients naïve to eradication therapy with non-investigated/functional dyspepsia or peptic ulcer disease were included. Randomised (1:1) to sequential (omeprazole (20 mg/12 h) and amoxicillin (1 g/12 h) for 5 days, followed by 5 days of omeprazole (20 mg/12 h), clarithromycin (500 mg/12 h) and metronidazole (500 mg/12 h)), or concomitant treatment (same drugs taken concomitantly for 10 days). Eradication was confirmed with (13)C-urea breath test or histology 4 weeks after treatment. Adverse events (AEs) and compliance were evaluated with questionnaires and residual medication count. RESULTS: 338 consecutive patients were randomised. Mean age was 47 years, 60% were women, 22% smokers and 20% had peptic ulcer. Concomitant and sequential eradication rates were, respectively, 87% vs 81% by intention-to-treat (p=0.15) and 91% vs 86% (p=0.131) per protocol. Respective compliances were 83% vs 82%. Treatment-emergent AEs were reported in 59% of patients (no differences found between treatments). AEs were mostly mild (60%), and average length was 6.1 days, causing discontinuation only in 12 patients. Multivariate analysis: 'concomitant' treatment showed an OR of 1.5 towards better eradication rate in a borderline significance CI (95% CI 0.9 to 2.8). CONCLUSIONS: Concomitant therapy led to a non-statistically significant advantage (5%) over sequential therapy, coming closer to 90% cure rates. Both therapies showed an acceptable safety profile. ClincialTrials.gov: NCT01273441.

Second-line rescue triple therapy with levofloxacin after failure of non-bismuth quadruple "sequential" or "concomitant" treatment to eradicate H. pylori infection.

BACKGROUND: Non-bismuth quadruple "sequential" and "concomitant" regimens, including a proton pump inhibitor (PPI), amoxicillin, clarithromycin and a nitroimidazole, are increasingly used as first-line treatments for Helicobacter pylori infection. Eradication with rescue regimens may be challenging after failure of key antibiotics such as clarithromycin and nitroimidazoles. AIM: To evaluate the efficacy and tolerability of a second-line levofloxacin-containing triple regimen (PPI-amoxicillin-levofloxacin) in the eradication of H. pylori after non-bismuth quadruple-containing treatment failure. DESIGN: prospective multicenter study. PATIENTS: in whom a non-bismuth quadruple regimen, administered either sequentially (PPI + amoxicillin for 5 days followed by PPI + clarithromycin + metronidazole for 5 more days) or concomitantly (PPI + amoxicillin + clarithromycin + metronidazole for 10 days) had previously failed. INTERVENTION: levofloxacin (500 mg b.i.d.), amoxicillin (1 g b.i.d.) and PPI (standard dose b.i.d.) for 10 days. OUTCOME: eradication was confirmed with (13)C-urea breath test 4-8 weeks after therapy. Compliance and tolerance: compliance was determined through questioning and recovery of empty medication envelopes. Incidence of adverse effects was evaluated by means of a questionnaire. RESULTS: 100 consecutive patients were included (mean age 50 years, 62% females, 12% peptic ulcer and 88% dyspepsia): 37 after "sequential", and 63 after "concomitant" treatment failure. All patients took all medications correctly. Overall, per-protocol and intention-to-treat H. pylori eradication rates were 75.5% (95% CI 66-85%) and 74% (65-83%). Respective intention-to-treat cure rates for "sequential" and "concomitant" failure regimens were 74.4% and 71.4%, respectively. Adverse effects were reported in six (6%) patients; all of them were mild. CONCLUSION: Ten-day levofloxacin-containing triple therapy constitutes an encouraging second-line strategy in patients with previous non-bismuth quadruple "sequential" or "concomitant" treatment failure.

A review of rescue regimens after clarithromycin-containing triple therapy failure (for Helicobacter pylori eradication).

INTRODUCTION: Helicobacter pylori infection is generally treated with therapies that include a proton pump inhibitor (PPI) and, at least, two antibiotics being clarithromycin one of the most used. Antibiotic resistance, mainly to clarithromycin, seems to be increasing in many geographical areas, and this factor is considered a main cause leading to a treatment failure when the later therapies contain this antibiotic again. As clarithromycin is a key antibiotic in the eradication of H. pylori, the election of the rescue treatment is a matter of debate. AREAS COVERED: The aim of this study is to systematically review the efficacy of the second-line rescue therapies after the failure of a first-line clarithromycin-containing regimen, and to link this information with the previous first-line treatment. Also, authors performed meta-analyses and inverse variance analyses with studies that met the inclusion criteria: first-line treatment must specify type and dosage; diagnosis and eradication confirmation must be performed by generally accepted tests; and second-line treatment must not be assigned depending on the antibiotic susceptibility or resistance. EXPERT OPINION: In a routine clinical practice setting, the most adequate second-line treatment consists in a 10-day regimen of levofloxacin- amoxicillin-PPI given twice daily, unless regional or new data show high quinolone resistance. Other good options are the bismuth quadruple regimen and a metronidazole-amoxicillin-PPI therapy.