Repurposing dried blood spot device technology to examine bile acid profiles in human dried fecal spot samples.

Dried blood spot (DBS) analysis has existed for >50 years, but application of this technique to fecal analysis remains limited. To address whether dried fecal spots (DFS) could be used to measure fecal bile acids, we collected feces from five subjects for each of the following cohorts: 1) healthy individuals, 2) individuals with diarrhea, and 3) Clostridioides difficile-infected patients. Homogenized fecal extracts were loaded onto quantitative DBS (qDBS) devices, dried overnight, and shipped to the bioanalytical lab at ambient temperature. For comparison, source fecal extracts were shipped on dry ice and stored frozen. After 4 mo, frozen fecal extracts and ambient DFS samples were processed and subjected to targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolomics with stable isotope-labeled standards. We observed no differences in the bile acid levels measured between the traditional extraction and the qDBS-based DFS methods. This pilot data demonstrates that DFS-based analysis is feasible and warrants further development for fecal compounds and microbiome applications.NEW & NOTEWORTHY Stool analysis in remote settings can be challenging, as the samples must be stored at -80°C and transported on dry ice for downstream processing. Our work indicates that dried fecal spots (DFS) on Capitainer quantitative DBS (qDBS) devices can be stored and shipped at ambient temperature and yields the same bile acid profiles as traditional samples. This approach has broad applications for patient home testing and sample collection in rural communities or resource-limited countries.

CORE-IBD: A Multidisciplinary International Consensus Initiative to Develop a Core Outcome Set for Randomized Controlled Trials in Inflammatory Bowel Disease.

BACKGROUND & AIMS: End points to determine the efficacy and safety of medical therapies for Crohn's disease (CD) and ulcerative colitis (UC) are evolving. Given the heterogeneity in current outcome measures, harmonizing end points in a core outcome set for randomized controlled trials is a priority for drug development in inflammatory bowel disease. METHODS: Candidate outcome domains and outcome measures were generated from systematic literature reviews and patient engagement surveys and interviews. An iterative Delphi process was conducted to establish consensus: panelists anonymously voted on items using a 9-point Likert scale, and feedback was incorporated between rounds to refine statements. Consensus meetings were held to ratify the outcome domains and core outcome measures. Stakeholders were recruited internationally, and included gastroenterologists, colorectal surgeons, methodologists, and clinical trialists. RESULTS: A total of 235 patients and 53 experts participated. Patient-reported outcomes, quality of life, endoscopy, biomarkers, and safety were considered core domains; histopathology was an additional domain for UC. In CD, there was consensus to use the 2-item patient-reported outcome (ie, abdominal pain and stool frequency), Crohn's Disease Activity Index, Simple Endoscopic Score for Crohn's Disease, C-reactive protein, fecal calprotectin, and co-primary end points of symptomatic remission and endoscopic response. In UC, there was consensus to use the 9-point Mayo Clinic Score, fecal urgency, Robarts Histopathology Index or Geboes Score, fecal calprotectin, and a composite primary end point including both symptomatic and endoscopic remission. Safety outcomes should be reported using the Medical Dictionary for Regulatory Activities. CONCLUSIONS: This multidisciplinary collaboration involving patients and clinical experts has produced the first core outcome set that can be applied to randomized controlled trials of CD and UC.

A Randomized Trial Comparing the Specific Carbohydrate Diet to a Mediterranean Diet in Adults With Crohn's Disease.

BACKGROUND & AIMS: This study compared the effectiveness of the Specific Carbohydrate Diet (SCD) to the Mediterranean diet (MD) as treatment for Crohn's disease (CD) with mild to moderate symptoms. METHODS: Adult patients with CD and with mild-to-moderate symptoms were randomly assigned 1:1 to consume the MD or SCD for 12 weeks. For the first 6 weeks, participants received prepared meals and snacks according to their assigned diet. After 6 weeks, participants were instructed to follow the diet independently. The primary outcome was symptomatic remission at week 6. Key secondary outcomes at week 6 included fecal calprotectin (FC) response (FC <250 µg/g and reduction by >50% among those with baseline FC >250 µg/g) and C-reactive protein (CRP) response (high-sensitivity CRP <5 mg/L and >50% reduction from baseline among those with high-sensitivity CRP >5 mg/L). RESULTS: The study randomized 194 patients, and 191 were included in the efficacy analyses. The percentage of participants who achieved symptomatic remission at week 6 was not superior with the SCD (SCD, 46.5%; MD, 43.5%; P = .77). FC response was achieved in 8 of 23 participants (34.8%) with the SCD and in 4 of 13 participants (30.8%) with the MD (P = .83). CRP response was achieved in 2 of 37 participants (5.4%) with the SCD and in 1 of 28 participants (3.6%) with the MD (P = .68). CONCLUSIONS: The SCD was not superior to the MD to achieve symptomatic remission, FC response, and CRP response. CRP response was uncommon. Given these results, the greater ease of following the MD and other health benefits associated with the MD, the MD may be preferred to the SCD for most patients with CD with mild to moderate symptoms. ClinicalTrials.gov Identifier: NCT03058679.

Fusobacteriumnucleatum Adheres to Clostridioides difficile via the RadD Adhesin to Enhance Biofilm Formation in Intestinal Mucus.

BACKGROUND & AIMS: Although Clostridioides difficile infection (CDI) is known to involve the disruption of the gut microbiota, little is understood regarding how mucus-associated microbes interact with C difficile. We hypothesized that select mucus-associated bacteria would promote C difficile colonization and biofilm formation. METHODS: To create a model of the human intestinal mucus layer and gut microbiota, we used bioreactors inoculated with healthy human feces, treated with clindamycin and infected with C difficile with the addition of human MUC2-coated coverslips. RESULTS: C difficile was found to colonize and form biofilms on MUC2-coated coverslips, and 16S rRNA sequencing showed a unique biofilm profile with substantial cocolonization with Fusobacterium species. Consistent with our bioreactor data, publicly available data sets and patient stool samples showed that a subset of patients with C difficile infection harbored high levels of Fusobacterium species. We observed colocalization of C difficile and F nucleatum in an aggregation assay using adult patients and stool of pediatric patients with inflammatory bowel disease and in tissue sections of patients with CDI. C difficile strains were found to coaggregate with F nucleatum subspecies in vitro; an effect that was inhibited by blocking or mutating the adhesin RadD on Fusobacterium and removal of flagella on C difficile. Aggregation was shown to be unique between F nucleatum and C difficile, because other gut commensals did not aggregate with C difficile. Addition of F nucleatum also enhanced C difficile biofilm formation and extracellular polysaccharide production. CONCLUSIONS: Collectively, these data show a unique interaction of between pathogenic C difficile and F nucleatum in the intestinal mucus layer.

Safety, Pharmacokinetics, and Efficacy of Olorinab, a Peripherally Acting, Highly Selective, Full Agonist of the Cannabinoid Receptor 2, in a Phase 2a Study of Patients With Chronic Abdominal Pain Associated With Crohn's Disease.

Background: This randomized, open-label phase 2a study investigated the safety/tolerability, pharmacokinetics, and efficacy of olorinab-a highly selective, peripherally acting, full agonist of the cannabinoid receptor 2-in patients with Crohn's disease (CD) experiencing abdominal pain. Methods: Eligible subjects 18-80 years of age with quiescent to mildly active CD were randomized to receive olorinab 25 or 100 mg three times daily for 8 weeks. The primary objective was to assess safety/tolerability. Results: Fourteen subjects received olorinab 25 mg (N = 6) or 100 mg (N = 8). Ten subjects [4 (67%) in the 25-mg group and 6 (75%) in the 100-mg group] reported a total of 34 treatment-emergent adverse events (TEAEs; 32 grade 1/2, not serious events; 2 grade 3, serious, not treatment-related events). No dose reductions or discontinuations due to TEAEs or deaths were reported. Dose-proportional increases in olorinab exposure from 25 to 100 mg were observed, with minimal accumulation at both doses. At week 8, the mean (SD) change from baseline in average abdominal pain score at peak olorinab plasma concentrations was -4.61 (1.77) in the 25-mg group (P = 0.0043) and -4.57 (2.17) in the 100-mg group (P = 0.0036). The change from baseline at week 8 in the mean (SD) number of pain-free days per week was +1.60 (2.61) in the 25-mg group and +2.33 (3.62) in the 100-mg group. No subject required pain medication on study. Conclusions: Patients with quiescent to mildly active CD receiving olorinab experienced mild-to-moderate adverse events and an improvement in abdominal pain scores in this study.

Clinical and Mechanistic Characteristics of Current JAK Inhibitors in IBD.

Crohn's disease (CD) and ulcerative colitis (UC) are chronic, immune-mediated diseases of the gastrointestinal (GI) tract. Their etiology is complex and involves immune (eg, cytokines) and nonimmune (eg, environment) mediated contributions, causing inflammatory damage to the GI tract. Though cytokines contribute a major role in the inflammatory process of both CD and UC, there are some key differences in which cytokines are involved in the pathobiology of CD and UC. Over the past several years, new biologic-directed therapies have focused on controlling specific aspects of inflammation associated with both conditions. Although these treatments have benefited patients overall, approximately 30% of patients still do not respond to induction (initial) therapy, and up to 50% of patients lose response to treatment over a year. Many of these therapies are administered parenterally and have been associated with adverse events such as serious infections or malignancy. Therefore, there is a significant unmet medical need for these patients to minimize symptoms and promote GI healing. There are several therapeutic agents in the pipeline, including oral, small molecules, which hold much promise. One group of small molecules known as Janus kinase (JAK) inhibitors offers an additional option for treatment of chronic inflammatory conditions, based on currently available data. The article will focus on the potential benefits of JAK inhibitors as oral, small molecules, such as the potential role of selectivity, and potential risks.

Transition to Adult IBD Care: A Pilot Multi-Site, Telehealth Hybrid Intervention.

OBJECTIVE: Transition to adult IBD care continues to be a challenge. Efficacious models of improving transition to adult care in the United States are lacking. We present data from a pilot, prospective, non-randomized, intervention implemented at IBD centers in the Midwest and Southeast United States. DESIGN AND METHODS: Adolescents and young adults (AYAs; 16-20 years) with IBD and their parents completed a 4- to 5-month transition program (1 in-person group session; 4 individual telehealth sessions). Primary outcomes were feasibility (i.e., recruitment, retention, fidelity) and acceptability (i.e., program satisfaction). Secondary outcomes were changes in transition readiness, self-management skill acquisition, perceived readiness to transfer to adult care, and disease knowledge. RESULTS: The study exceeded goals for recruitment (target N = 20; actual: 36) and retention (target: 80%; actual: 86.11%). On average, it took participants 20.91 ± 3.15 weeks to complete our 4- to 5-month intervention and there were no deviations from the study protocol. Participant ratings for overall program satisfaction, perceived helpfulness, and program length and format were positive. Increases in transition readiness, t(30) = 8.30, d = 1.49, p < .001, self-management skill acquisition, t(30) = 3.93, d = 0.70, p < .001, and disease knowledge, t(30) = 8.20, d = 1.58, p < .001 were noted. AYA- and parent-perceived transfer readiness also improved (p's < .05; d's = 0.76-1.68). CONCLUSIONS: This article presents feasibility and acceptability data for a 4- to 5-month transition intervention. Improvements in AYA transition readiness, self-management skill acquisition, IBD knowledge, and AYA/parent perceived transfer readiness were also observed.

Therapeutic Opportunities for Intestinal Angioectasia- Targeting PPARγ and Oxidative Stress.

Recurrent and acute bleeding from intestinal tract angioectasia (AEC) presents a major challenge for clinical intervention. Current treatments are empiric, with frequent poor clinical outcomes. Improvements in understanding the pathophysiology of these lesions will help guide treatment. Using data from the US Food and Drug Administration (FDA)'s Adverse Event Reporting System (FAERS), we analyzed 12 million patient reports to identify drugs inversely correlated with gastrointestinal bleeding and potentially limiting AEC severity. FAERS analysis revealed that drugs used in patients with diabetes and those targeting PPARγ-related mechanisms were associated with decreased AEC phenotypes (P < 0.0001). Electronic health records (EHRs) at University of Cincinnati Hospital were analyzed to validate FAERS analysis. EHR data showed a 5.6% decrease in risk of AEC and associated phenotypes in patients on PPARγ agonists. Murine knockout models of AEC phenotypes were used to construct a gene-regulatory network of candidate drug targets and pathways, which revealed that wound healing, vasculature development and regulation of oxidative stress were impacted in AEC pathophysiology. Human colonic tissue was examined for expression differences across key pathway proteins, PPARγ, HIF1α, VEGF, and TGFß1. In vitro analysis of human AEC tissues showed lower expression of PPARγ and TGFß1 compared with controls (0.55 ± 0.07 and 0.49 ± 0.05). National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) RNA-Seq data was analyzed to substantiate human tissue findings. This integrative discovery approach showing altered expression of key genes involved in oxidative stress and injury repair mechanisms presents novel insight into AEC etiology, which will improve targeted mechanistic studies and more optimal medical therapy for AEC.

Systematic Review and Meta-Analyses Assessment of the Clinical Efficacy of Bismuth Subsalicylate for Prevention and Treatment of Infectious Diarrhea.

BACKGROUND: A large number of studies have evaluated the pharmacology, safety, and/or efficacy of bismuth subsalicylate for the relief of common gastrointestinal symptoms, diarrhea and vomiting due to acute gastroenteritis. In addition, short-term (48 h) medication with bismuth subsalicylate is known to be effective against infectious gastroenteritis such as travelers' diarrhea. AIMS: Previous studies have documented the bacteriostatic/bactericidal effects of bismuth subsalicylate against a variety of pathogenic gastrointestinal bacteria. However, meta-analyses of the clinical efficacy of bismuth subsalicylate for both prevention and treatment of travelers' diarrhea have not yet been published. METHODS: A total of 14 clinical studies (from 1970s to 2007) comprised the core data used in this assessment of efficacy of bismuth subsalicylate against infectious (including travelers') diarrhea. These studies allowed for statistical meta-analyses regarding prevention (three travelers' diarrhea studies) and treatment of infectious diarrhea (11 studies [five travelers' diarrhea]). RESULTS: The results show that subjects treated with bismuth subsalicylate for up to 21 days have 3.5 times greater odds of preventing travelers' diarrhea compared with placebo (95% CI 2.1, 5.9; p < 0.001). In addition, subjects with infectious diarrhea treated with bismuth subsalicylate had 3.7 times greater odds of diarrhea relief (recorded on diaries as subjective symptomatic improvement) compared to those receiving placebo (95% CI 2.1, 6.3; p < 0.001). CONCLUSIONS: This systematic review and meta-analysis suggests that bismuth subsalicylate can be beneficial for those at risk or affected by food and waterborne diarrheal disease such as traveler's (infectious) diarrhea, and may decrease the risk of inappropriate antibiotic utilization.

Efficacy and Safety of Etrasimod in a Phase 2 Randomized Trial of Patients With Ulcerative Colitis.

BACKGROUND & AIMS: Etrasimod (APD334) is an oral, selective sphingosine 1-phosphate receptor modulator in development for immune-mediated inflammatory disorders. We assessed the efficacy and safety of etrasimod in patients with moderately to severely active ulcerative colitis (UC). METHODS: In a phase 2, proof-of-concept, double-blind, parallel-group study, adult outpatients with modified Mayo Clinic scores (MCSs) (stool frequency, rectal bleeding, and endoscopy findings) of 4-9, endoscopic subscores of 2 or more, and rectal bleeding subscores of 1 or more were randomly assigned to groups given once-daily etrasimod 1 mg (n = 52), etrasimod 2 mg (n = 50), or placebo (n = 54) for 12 weeks. The study was performed from October 15, 2015, through February 14, 2018, at 87 centers in 17 countries. The primary endpoint was an increase in the mean improvement in modified MCS from baseline to week 12. Secondary endpoints included the proportion of patients with endoscopic improvement (subscores of 1 or less) from baseline to week 12. Exploratory endpoints, including clinical remission, are reported in the article, although the study was statistically powered to draw conclusions only on the primary endpoint. RESULTS: At week 12, the etrasimod 2 mg group met the primary and all secondary endpoints. Etrasimod 2 mg led to a significantly greater increase in mean improvement in modified MCS from baseline than placebo (difference from placebo, 0.99 points; 90% confidence interval, 0.30-1.68; P = .009), and etrasimod 1 mg led to an increase in mean improvement from baseline in modified MCS of 0.43 points more than placebo (90% confidence interval, reduction of 0.24 to increase of 1.11; nominal P = .15). Endoscopic improvement occurred in 41.8% of patients receiving etrasimod 2 mg vs 17.8% receiving placebo (P = .003). Most adverse events were mild to moderate. Three patients had a transient, asymptomatic, low-grade atrioventricular block that resolved spontaneously all patients had evidence of atrioventricular block before etrasimod exposure. CONCLUSIONS: In patients with moderately to severely active ulcerative colitis, etrasimod 2 mg was more effective than placebo in producing clinical and endoscopic improvements. Further clinical development is warranted. Clinicaltrials.gov, Number: NCT02447302.

Gut microbiota and obesity: An opportunity to alter obesity through faecal microbiota transplant (FMT).

Obesity is a global pandemic with immense health consequences for individuals and societies. Multiple factors, including environmental influences and genetic predispositions, are known to affect the development of obesity. Despite an increasing understanding of the factors driving the obesity epidemic, therapeutic interventions to prevent or reverse obesity are limited in their impact. Manipulation of the human gut microbiome provides a new potential therapeutic approach in the fight against obesity. Specific gut bacteria and their metabolites are known to affect host metabolism and feeding behaviour, and dysbiosis of this biosystem may lead to metabolic syndrome. Potential therapies to alter the gut microbiota to treat obesity include dietary changes, supplementation of the diet with probiotic organisms and prebiotic compounds that influence bacterial growth, and the use of faecal microbiota transplant, in which gut microbiota from healthy individuals are introduced into the gut. In this review, we examine the growing scientific evidence supporting the mechanisms by which the human gut microbiota may influence carbohydrate metabolism and obesity, and the various possible therapies that may utilize the gut microbiota to help correct metabolic dysfunction.

Bezlotoxumab for Prevention of Recurrent Clostridium difficile Infection in Patients at Increased Risk for Recurrence.

Background: Bezlotoxumab is a human monoclonal antibody against Clostridium difficile toxin B indicated to prevent C. difficile infection (CDI) recurrence (rCDI) in adults at high risk for rCDI. This post hoc analysis of pooled monocolonal antibodies for C.difficile therapy (MODIFY) I/II data assessed bezlotoxumab efficacy in participants with characteristics associated with increased risk for rCDI. Methods: The analysis population was the modified intent-to-treat population who received bezlotoxumab or placebo (n = 1554) by risk factors for rCDI that were prespecified in the statistical analysis plan: age ≥65 years, history of CDI, compromised immunity, severe CDI, and ribotype 027/078/244. The proportion of participants with rCDI in 12 weeks, fecal microbiota transplant procedures, 30-day all cause and CDI-associated hospital readmissions, and mortality at 30 and 90 days after randomization were presented. Results: The majority of enrolled participants (75.6%) had ≥1 risk factor; these participants were older and a higher proportion had comorbidities compared with participants with no risk factors. The proportion of placebo participants who experienced rCDI exceeded 30% for each risk factor compared with 20.9% among those without a risk factor, and the rCDI rate increased with the number of risk factors (1 risk factor: 31.3%; ≥3 risk factors: 46.1%). Bezlotoxumab reduced rCDI, fecal microbiota transplants, and CDI-associated 30-day readmissions in participants with risk factors for rCDI. Conclusions: The risk factors prespecified in the MODIFY statistical analysis plan are appropriate to identify patients at high risk for rCDI. While participants with ≥3 risk factors had the greatest reduction of rCDI with bezlotoxumab, those with 1 or 2 risk factors may also benefit. Clinical Trials Registration: NCT01241552 (MODIFY I) and NCT01513239 (MODIFY II).

Clostridium difficile toxins A and B decrease intestinal SLC26A3 protein expression.

Clostridium difficile infection (CDI) is the primary cause of nosocomial diarrhea in the United States. Although C. difficile toxins A and B are the primary mediators of CDI, the overall pathophysiology underlying C. difficile-associated diarrhea remains poorly understood. Studies have shown that a decrease in both NHE3 (Na+/H+ exchanger) and DRA (downregulated in adenoma, Cl-/[Formula: see text] exchanger), resulting in decreased electrolyte absorption, is implicated in infectious and inflammatory diarrhea. Furthermore, studies have shown that NHE3 is depleted at the apical surface of intestinal epithelial cells and downregulated in patients with CDI, but the role of DRA in CDI remains unknown. In the current studies, we examined the effects of C. difficile toxins TcdA and TcdB on DRA protein and mRNA levels in intestinal epithelial cells (IECs). Our data demonstrated that DRA protein levels were significantly reduced in response to TcdA and TcdB in IECs in culture. This effect was also specific to DRA, as NHE3 and PAT-1 (putative anion transporter 1) protein levels were unaffected by TcdA and TcdB. Additionally, purified TcdA and TcdA + TcdB, but not TcdB, resulted in a decrease in colonic DRA protein levels in a toxigenic mouse model of CDI. Finally, patients with recurrent CDI also exhibited significantly reduced expression of colonic DRA protein. Together, these findings indicate that C. difficile toxins markedly downregulate intestinal expression of DRA which may contribute to the diarrheal phenotype of CDI. NEW & NOTEWORTHY Our studies demonstrate, for the first time, that C. difficile toxins reduce DRA protein, but not mRNA, levels in intestinal epithelial cells. These findings suggest that a downregulation of DRA may be a critical factor in C. difficile infection-associated diarrhea.

Efficacy and safety of ridinilazole compared with vancomycin for the treatment of Clostridium difficile infection: a phase 2, randomised, double-blind, active-controlled, non-inferiority study.

BACKGROUND: Clostridium difficile infection is the most common health-care-associated infection in the USA. We assessed the safety and efficacy of ridinilazole versus vancomycin for treatment of C difficile infection. METHODS: We did a phase 2, randomised, double-blind, active-controlled, non-inferiority study. Participants with signs and symptoms of C difficile infection and a positive diagnostic test result were recruited from 33 centres in the USA and Canada and randomly assigned (1:1) to receive oral ridinilazole (200 mg every 12 h) or oral vancomycin (125 mg every 6 h) for 10 days. The primary endpoint was achievement of a sustained clinical response, defined as clinical cure at the end of treatment and no recurrence within 30 days, which was used to establish non-inferiority (15% margin) of ridinilazole versus vancomycin. The primary efficacy analysis was done on a modified intention-to-treat population comprising all individuals with C difficile infection confirmed by the presence of free toxin in stool who were randomly assigned to receive one or more doses of the study drug. The study is registered with ClinicalTrials.gov, number NCT02092935. FINDINGS: Between June 26, 2014, and August 31, 2015, 100 patients were recruited; 50 were randomly assigned to receive ridinilazole and 50 to vancomycin. 16 patients did not complete the study, and 11 discontinued treatment early. The primary efficacy analysis included 69 patients (n=36 in the ridinilazole group; n=33 in the vancomycin group). 24 of 36 (66·7%) patients in the ridinilazole group versus 14 of 33 (42·4%) of those in the vancomycin group had a sustained clinical response (treatment difference 21·1%, 90% CI 3·1-39·1, p=0·0004), establishing the non-inferiority of ridinilazole and also showing statistical superiority at the 10% level. Ridinilazole was well tolerated, with an adverse event profile similar to that of vancomycin: 82% (41 of 50) of participants reported adverse events in the ridinilazole group and 80% (40 of 50) in the vancomycin group. There were no adverse events related to ridinilazole that led to discontinuation. INTERPRETATION: Ridinilazole is a targeted-spectrum antimicrobial that shows potential in treatment of initial C difficile infection and in providing sustained benefit through reduction in disease recurrence. Further clinical development is warranted. FUNDING: Wellcome Trust and Summit Therapeutics.

Canonical Wnt Signaling Ameliorates Aging of Intestinal Stem Cells.

Although intestinal homeostasis is maintained by intestinal stem cells (ISCs), regeneration is impaired upon aging. Here, we first uncover changes in intestinal architecture, cell number, and cell composition upon aging. Second, we identify a decline in the regenerative capacity of ISCs upon aging because of a decline in canonical Wnt signaling in ISCs. Changes in expression of Wnts are found in stem cells themselves and in their niche, including Paneth cells and mesenchyme. Third, reactivating canonical Wnt signaling enhances the function of both murine and human ISCs and, thus, ameliorates aging-associated phenotypes of ISCs in an organoid assay. Our data demonstrate a role for impaired Wnt signaling in physiological aging of ISCs and further identify potential therapeutic avenues to improve ISC regenerative potential upon aging.

Epithelial Regeneration After Gastric Ulceration Causes Prolonged Cell-Type Alterations.

BACKGROUND & AIMS: The peptic ulcer heals through a complex process, although the ulcer relapse often occurs several years later after healing. Our hypothesis is that even after visual evidence of healing of gastric ulceration, the regenerated epithelium is aberrant for an extended interval, increasing susceptibility of the regenerated epithelium to damage and further diseases. METHODS: Gastric ulcers were induced in mice by serosal topical application of acetic acid. RESULTS: Gastric ulcers induced by acetic acid visually healed within 30 days. However, regenerated epithelial architecture was poor. The gene profile of regenerated tissue was abnormal, indicating increased stem/progenitor cells, deficient differentiated gastric cell types, and deranged cell homeostasis. Despite up-regulation of PDX1 in the regenerated epithelium, no mature antral cell type was observed. Four months after healing, the regenerated epithelium lacks parietal cells, trefoil factor 2 (TFF2) and (sex-determining region Y)-box 9 (SOX9) remain up-regulated deep in the gastric gland, and the Na/H exchanger 2 (a TFF2 effector in gastric healing) remains down-regulated. Gastric ulcer healing was strongly delayed in TFF2 knockout mice, and re-epithelialization was accompanied with mucous metaplasia. After Helicobacter pylori inoculum 30 days after ulceration, we observed that the gastric ulcer selectively relapses at the same site where it originally was induced. Follow-up evaluation at 8 months showed that the relapsed ulcer was not healed in H pylori-infected tissues. CONCLUSIONS: These findings show that this macroscopically regenerated epithelium has prolonged abnormal cell distribution and is differentially susceptible to subsequent damage by H pylori.

Importance of the Evaluation of N-Acetyltransferase Enzyme Activity Prior to 5-Aminosalicylic Acid Medication for Ulcerative Colitis.

BACKGROUND: 5-aminosalicylic acid (5-ASA) is a classic anti-inflammatory drug for the treatment of ulcerative colitis. N-acetyltransferase (NAT) enzymes convert 5-ASA to its metabolite N-acetyl-5-ASA, and it is unresolved whether 5-ASA or N-acetyl-5-ASA is the effective therapeutic molecule. We previously demonstrated that colonic production of N-acetyl-5-ASA (NAT activity) is decreased in dextran sulfate sodium-induced colitis. Our hypothesis is that 5-ASA is the therapeutic molecule to improve colitis, with the corollary that altered NAT activity affects drug efficacy. Since varying clinical effectiveness of 5-ASA has been reported, we also ask if NAT activity varies with inflammation in pediatric or adult patients. METHODS: Acute colonic inflammation was induced in C57BL/6 NAT wild-type (WT) or knockout mice, using 3.5% dextran sulfate sodium (w/v) concurrent with 5-ASA treatment. Adult and pediatric rectosigmoid biopsies were collected from control or patients with ulcerative colitis. Tissue was analyzed for NAT and myeloperoxidase activity. RESULTS: Dextran sulfate sodium-induced colitis was of similar severity in both NAT WT and knockout mice, and NAT activity was significantly decreased in NAT WT mice. In the setting of colitis, 5-ASA significantly restored colon length and decreased myeloperoxidase activity in NAT knockout but not in WT mice. Myeloperoxidase activity negatively correlated with NAT activity in pediatric patients, but correlation was not observed in adult patients. CONCLUSIONS: Inflammation decreases NAT activity in the colon of mice and human pediatric patients. Decreased NAT activity enhances the therapeutic effect of 5-ASA in mice. A NAT activity assay could be useful to help predict the efficacy of 5-ASA therapy.