A39 HEALTHY FIRST-DEGREE RELATIVES FROM MULTIPLEX FAMILIES VERSUS SIMPLEX HARBOR A HIGHER RISK OF DEVELOPING CROHN'S DISEASE AND ARE ASSOCIATED WITH SUBCLINICAL INFLAMMATION AND ALTERED MICROBIOME COMPOSITION

Background

Healthy individuals within families with multiple affected members (multiplex families) with Crohn’s disease (CD) have a notably high risk of developing CD. No large prospective pre-disease cohort has assessed differences in preclinical intestinal inflammation, permeability, fecal microbiome, and genetics in healthy at-risk subjects from multiplex families.

Purpose

We aimed to assess differences in subclinical gut inflammation, genetic risk, gut barrier function, and fecal microbiota composition between first-degree relatives (FDRs) from families with 2 or more affected members (multiplex) and families with only one affected member (simplex). Also, we aimed to assess the risk of future CD onset in subjects from multiplex versus simplex families.

Method

We utilized the GEM Project cohort of healthy FDRs of CD patients. Subclinical gut inflammation was assessed using fecal calprotectin (FCP) at recruitment. Gut barrier function was assessed using the lactulose-to-mannitol ratio (LMR). For assessment of the CD-related genetic risk, CD-polygenic risk scores (CD-PRS) were calculated. Microbiome composition was assessed by sequencing fecal 16S ribosomal RNA. Generalized estimating equations logistic regression and LEfSe (PMID: 21702898) were used to assess the associations between multiplex status and different outcomes. A Cox proportional hazards model was used to assess time-related risk of future onset of CD.

Result(s)

4385 subjects were included. Median age was 17 [IQR 12-24] years, 52.9% were female, 69.4% were siblings and 30.6% were offspring. 4052 (92.4%) and 333 (7.6 %) were simplex and multiplex subjects, respectively. After adjusting for age, sex, family size, and relation to proband, multiplex status was significantly associated with higher baseline FCP (p=0.038), but was not associated with either baseline LMR or CD-PRS (p=0.19 and p=0.33, respectively).

We found no significant differences in alpha diversity (Shannon index) (p=0.57) between simplex and multiplex subjects. Beta diversity analysis assessed by the Bray-Curtis dissimilarity index did not reveal significant differences (R2=3e-04, p=0.607). The genera Eisenbergiella, Eggerthellaceae uncultured, and Morganella, were significantly more abundant in multiplex subjects, whereas Lachnospira, Sutterella, Lachnospiraceae_NK4A136_group, and Lachnospiraceae_UCG_004 less abundant.

The risk of CD onset was significantly higher in multiplex subjects. In multivariable analysis, multiplex status at recruitment was associated with increased risk of CD onset (adjusted HR 3.41, 95% CI 1.70-6.87, p=0.00055), after adjusting for demographics, FCP, LMR, and CD-PRS.

Conclusion(s)

Multiplex status compared to simplex is associated with a 3.4-fold increased risk of CD onset, a higher FCP, and fecal bacterial composition. A comprehensive assessment of environmental factors that increase CD risk in multiplex families remains to be elucidated in future studies.

Disclosure of Interest

None Declared

Determination of atmospheric aerosol components in an urban area to evaluate the air quality and identify the sources of contamination

The need to generate objective evidence and reliable information for decision makers to improve environmental policies for a better air quality, led us to evaluate the atmospheric aerosol components in the urban area of Carabayllo, by monitoring PM2.5 and PM10 to determine mass concentration and analyzing PM10 using k 0-INAA and ICP-MS for metals quantification, ion chromatography for anions and the NIOSH method to determine organic and elemental carbon. The results obtained from mass concentration of PM2.5 and PM10 exceeded the permissible breathing annual average of WHO guidelines of 15 µgm-3 and 45 µgm-3, respectively, which evidence an unhealthy air quality. Likewise, using the model Positive Matrix Factorization five sources of pollutants were defined: metallurgical industry, sea salt, industrial activity, dust and non-exhaust emissions and vehicle emissions.

Comparison of antibody response to SARS-CoV-2 after two doses of inactivated virus and BNT162b2 mRNA vaccines in kidney transplant

Background

Antibody response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after mRNA or adenoviral vector-based vaccines is weak in kidney transplant (KT) patients. However, few studies have focused on humoral response after inactivated virus-based vaccines in KT. Here, we compare antibody response following vaccination with inactivated virus (CoronaVac®) and BNT162b2 mRNA.

Methods

A national multicentre cross-sectional study was conducted. The study group was composed of patients from all KT centres in Uruguay, vaccinated between 1 and 31 May 2021 (CoronaVac®, n = 245 and BNT162b2, n = 39). The control group was constituted of 82 healthy individuals. Participants had no prior confirmed coronavirus disease 2019 (COVID-19) test. Blood samples were collected between 30 and 40 days after the second dose. Serum-specific immunoglobulin G (IgG) antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 Spike protein were determined using the COVID-19 IgG QUANT ELISA Kit.

Results

Only 29% of KT recipients showed seroconversion (36.5% BNT162b2, 27.8% inactivated virus, P = 0.248) in comparison with 100% in healthy control with either vaccine. Antibody levels against RBD were higher with BNT162b mRNA than with inactivated virus [median (interquartile range) 173 (73–554) and 29 (11–70) binding antibody units (BAU)/mL, P < 0.034] in KT and 10 times lower than healthy control [inactivated virus: 308 (209–335) and BNT162b2: 2638 (2608–3808) BAU/mL, P < 0.034]. In multivariate analysis, variables associated with negative humoral response were age, triple immunosuppression, estimated glomerular filtration rate and time post-KT.

Conclusion

Seroconversion was low in KT patients after vaccination with both platforms. Antibody levels against SARS-CoV-2 were lower with inactivated virus than BNT162b mRNA. These findings support the need for strategies to improve immunogenicity in KT recipients after two doses of either vaccine.

Effect of successive endoscopic procedures in polyp and adenoma detection rates: Too early is not always too good

BACKGROUND AND AIMS: There is conflicting evidence regarding the impact of hypothetical cumulative fatigue after performing too many endoscopic procedures on both polyp and adenoma detection rates (PDR, and ADR, respectively). The aim of this study is to evaluate the effect of successive endoscopic procedures on PDR and ADR.

METHODS

A retrospective cross-sectional study was undertaken among consecutive patients on whom colonoscopy and/or esophagogastroduodenoscopy were performed between January 2012 and August 2014. Data regarding polyp and adenoma detection, cecal intubation, and bowel cleansing quality as well as demographical data of subjects were extracted. Endoscopic procedures were classified according to the time slots of the procedures throughout the endoscopy session in three groups: from the 1st to 4th endoscopy study (round 1), from the 5th to the 8th study (round 2), above the 9th study (round 3). We compared PDR and ADR among rounds.

RESULTS

Overall, 3388 patients were enrolled. Median age was 50 years (range 18-95) and 52.39% were female. There was a significant difference in terms of PDR among rounds (36.83%, 41.24%, and 43.38%, respectively, p = 0.007) and a non-significant numerical difference when ADR was compared (23.2%, 25.71%, and 26.78%, p = 0.07). On multivariate analysis, ADR was significantly associated with age (odds ratio [OR] 1.02 [1.01-1.03]), and male sex (OR 1.64 [1.38-1.94]).

CONCLUSION

Theoretical endoscopist's fatigue due to cumulative performance of endoscopies does not diminish colonoscopy quality. Both PDR and ADR seem to improve after endoscopist's cumulative rounds of performed endoscopies. This could be due to a "warm-up" effect.

Physicians' perspective on the clinical meaningfulness of inflammatory bowel disease trial results: an International Organization for the Study of Inflammatory Bowel Disease (IOIBD) survey

BACKGROUND

Several novel compounds are being developed for inflammatory bowel diseases (IBD). In addition, biosimilar drugs are being approved. An increasing number of head-to-head, superiority and non-inferiority trials in patients with IBD are expected in the future. The clinical relevance of the magnitude of the effect size is often debated.

AIM

To better understand physicians' perspectives on the clinical meaningfulness of IBD trial results.

METHODS

We conducted an online survey among all IOIBD (International Organization for the Study of Inflammatory Bowel Diseases) members, asking their opinion on the clinical relevance of the results of IBD trials.

RESULTS

Forty-six IOIBD members responded to the survey (52.3%). In biologic-naïve ulcerative colitis (UC) and Crohn's disease (CD) patients, most of the participants considered a 15% difference with placebo for clinical remission and endoscopic remission to be clinically relevant. In head-to-head trials, most of participants considerer a 10% difference between groups for clinical remission and endoscopic remission to be clinically relevant. Half of respondents considered 10% to be an adequate margin in non-inferiority trials. In bioequivalence studies, most of the participants considered adequate a ± 5% difference between a biosimilar and the originator for pharmacokinetic parameters, efficacy, safety and immunogenicity. Regarding safety, the difference between two drugs considered clinically relevant varied from 1% to 5%, depending on the type of adverse event.

CONCLUSIONS

This is the first survey exploring how physicians perceive IBD trial results, providing an estimation of the magnitude of the difference between treatment arms that may directly influence clinical practice.

Iron-deficiency anemia as a subclinical celiac disease presentation in an Argentinian population

BACKGROUND

There is a wide heterogeneity in the reports of celiac disease prevalence in iron-deficiency anemia patients.

AIM

To determine the prevalence of celiac disease in patients with iron-deficiency anemia.

MATERIALS AND METHODS

Adult patients with a diagnosis of iron-deficiency anemia were enrolled for upper endoscopy with duodenal biopsies. Healthy volunteers that underwent upper endoscopy were enrolled as controls.

RESULTS

A total of 135 patients with iron-deficiency anemia and 133 controls were enrolled. Celiac disease prevalence was higher in the iron-deficiency anemia group [11.11 vs. 1.51%, OR: 8.18 (1.83-36.55), P=.001). Of the celiac disease patients in the iron-deficiency anemia group, 73.3% had at least one endoscopic sign suggesting villous atrophy, whereas 100% of the celiac disease patients in the control group presented with at least one endoscopic sign.

CONCLUSIONS

Patients with iron-deficiency anemia have an increased risk for celiac disease. Up to 25% of these patients may not present any endoscopic sign suggesting villous atrophy.

Review article: moving towards common therapeutic goals in Crohn's disease and rheumatoid arthritis

BACKGROUND

Crohn's disease (CD) and rheumatoid arthritis are chronic, progressive and disabling conditions that frequently lead to structural tissue damage. Based on strategies originally developed for rheumatoid arthritis, the treatment goal for CD has recently moved from exclusively controlling symptoms to both clinical remission and complete mucosal healing (deep remission), with the final aim of preventing bowel damage and disability.

AIM

To review the similarities and differences in treatment goals between CD and rheumatoid arthritis.

METHODS

This review examined manuscripts from 1982 to 2016 that discussed and/or proposed therapeutic goals with their supportive evidence in CD and rheumatoid arthritis.

RESULTS

Proposed therapeutic strategies to improve outcomes in both rheumatoid arthritis and CD include: (i) evaluation of musculoskeletal or organ damage and disability, (ii) tight control, (iii) treat-to-target, (iv) early intervention and (v) disease modification. In contrast to rheumatoid arthritis, there is a paucity of disease-modification trials in CD.

CONCLUSIONS

Novel therapeutic strategies in CD based on tight control of objective signs of inflammation are expected to change disease course and patients' lives by halting progression or, ideally, preventing the occurrence of bowel damage. Most of these strategies require validation in prospective studies, whereas several disease-modification trials have addressed these issues in rheumatoid arthritis over the last decade. The recent approval of new drugs in CD such as vedolizumab and ustekinumab should facilitate initiation of disease-modification trials in CD in the near future.

Small intestinal bacterial overgrowth prevalence in celiac disease patients is similar in healthy subjects and lower in irritable bowel syndrome patients

BACKGROUND

Untreated celiac disease has traditionally been linked to a greater risk for small intestinal bacterial overgrowth, but the existing evidence is inconclusive.

AIMS

To compare the prevalence of small intestinal bacterial overgrowth in subjects with celiac disease compared with control subjects and patients with irritable bowel syndrome.

MATERIAL AND METHODS

The study included 15 untreated celiac disease patients, 15 subjects with irritable bowel syndrome, and 15 healthy controls. All enrolled patients underwent a lactulose breath test measuring hydrogen and methane. Small intestinal bacterial overgrowth was defined according to previously published criteria.

RESULTS

No differences were found in relation to age or sex. The prevalence of small intestinal bacterial overgrowth was similar between the celiac disease patients and the controls (20 vs. 13.33%, P=NS), whereas it was higher in patients with irritable bowel syndrome (66.66%, P<05).

CONCLUSION

There was no difference in the prevalence of small intestinal bacterial overgrowth between the untreated celiac disease patients and healthy controls.

Role of metal ions on the activity of Mycobacterium tuberculosis pyrazinamidase

Pyrazinamidase of Mycobacterium tuberculosis catalyzes the conversion of pyrazinamide to the active molecule pyrazinoic acid. Reduction of pyrazinamidase activity results in a level of pyrazinamide resistance. Previous studies have suggested that pyrazinamidase has a metal-binding site and that a divalent metal cofactor is required for activity. To determine the effect of divalent metals on the pyrazinamidase, the recombinant wild-type pyrazinamidase corresponding to the H37Rv pyrazinamide-susceptible reference strain was expressed in Escherichia coli with and without a carboxy terminal. His-tagged pyrazinamidase was inactivated by metal depletion and reactivated by titration with divalent metals. Although Co(2+), Mn(2+), and Zn(2+) restored pyrazinamidase activity, only Co(2+) enhanced the enzymatic activity to levels higher than the wild-type pyrazinamidase. Cu(2+), Fe(2+), Fe(3+), and Mg(2+) did not restore the activity under the conditions tested. Various recombinant mutated pyrazinamidases with appropriate folding but different enzymatic activities showed a differential pattern of recovered activity. X-ray fluorescence and atomic absorbance spectroscopy showed that recombinant wild-type pyrazinamidase expressed in E. coli most likely contained Zn. In conclusion, this study suggests that M. tuberculosis pyrazinamidase is a metalloenzyme that is able to coordinate several ions, but in vivo, it is more likely to coordinate Zn(2+). However, in vitro, the metal-depleted enzyme could be reactivated by several divalent metals with higher efficiency than Zn.

Gemcitabine activity in cervical cancer cell lines

PURPOSE

Gemcitabine (2',2'-difluorodeoxycytidine) is an antineoplastic agent with activity against a variety of solid tumors. To investigate its in vitro activity toward cervical cancer, we exposed six cervical cancer cell lines to gemcitabine.

METHODS

Combinational cytotoxic studies using viability tests and clonogenicity assays.

RESULTS

Gemcitabine was cytostatic and cytotoxic in some of the lines at peak plasma concentrations similar to those achieved in clinical trials. Gemcitabine was also found to effectively synergize with cisplatin and showed a radiosensitizing effect in these cells. The cytotoxicity observed in sensitive cell lines was due to apoptosis, as demonstrated by DNA fragmentation assays.

CONCLUSIONS

We recommend performing additional in vitro experimentation so that these results can be confirmed to support clinical trials of gemcitabine in cervical cancer patients both as first-line therapy and with concomitant radiation.

Plasma lipids of golden Syrian hamsters fed dietary rose hip, sunflower, olive and coconut oils

Plasma lipids of male golden Syrian hamsters fed diets supplemented with 15% (w/w) rose hip, sunflower, olive, or coconut oils during four weeks were assessed. The results confirm the saturated fat hyperlipidemic effect on golden Syrian hamsters fed with the olive oil and coconut oil, reaching the highest triglyceride levels. The monounsaturated (olive oil) or polyunsaturated (rose hip and sunflower oils) fatty acid-rich-vegetable oils have a similar action on the HDL-cholesterol. No statistically significant difference was observed for total cholesterol, HDL-cholesterol and triglyceride plasma levels in the rose hip and sunflower groups, showing that the polyunsaturation degree of both oils does not affect those results. Compared with the plasma levels obtained in the olive and coconut oil groups, rose hip and sunflower oils present a marked hypolipidemic effect, which could be due to specific action of the series n-6 linoleic acid.

Early gastric cancer: an analysis of 44 cases with emphasis on the prognostic significance of the macroscopic and microscopic growth patterns

Forty-four consecutive cases of "early gastric cancer" were studied according to the macroscopic classification proposed by the Japanese Gastroenterological and Endoscopy Society and further analyzed in terms of growth patterns. The tumours were then classified into the small mucosal type, the superficially spreading (Super) type and the penetrating growth (Pen) type. The Lauren type (intestinal vs. diffuse), presence of lymphatic and venous invasion, and lymph node metastasis were also assessed. Most elevated tumours showed a superficial growth pattern and were classified as Lauren's intestinal type, whereas depressed lesions were associated with submucosal invasion and were classified as diffuse. Microscopic patterns did not show any correlation with Lauren's classification. Mean duration of follow-up was 67.8 months and the overall actuarial survival was 93%, 80%, and 72%, at 2, 5, and 10 years, respectively. Aside from venous invasion no correlation was found between survival and any of the morphological parameters analysed.