Introduction

Crohn’s disease (CD) is characterized by chronic intestinal inflammation due to genetic and environmental factors. Microbiome studies have consistently shown dysbiosis in patients with CD. Diet is an important risk factor in the development of CD and may contribute to changes in the gut microbiota (GM). We conducted a prospective diet intervention study in CD patients and compared one time diet counseling versus catered meals that were high fiber (17g/1000 calories) and low fat (20-25% calories from fat) for 8 weeks (w) and followed for a total of 36w.

Aims & Methods

We hypothesized that metaproteomic characterization of the GM in CD in the context of dietary manipulation could edify response to diet intervention therapy. Patients chose to receive diet counseling alone (group 1), catered food for 8 weeks (group 2), or catered food for a patient (group 3P) and a household control (HHC) (group 3C) as well as participate in Dyadic Psychosocial Support (DPS) sessions (group 3P and 3C). A total of 70 patients and 22 HHC were followed prospectively and collected stool at baseline, week 8, and week 36. Samples were processed with a proven pipeline to isolate and digest bacterial proteins to perform LC-MS analysis.¹ Samples with bacterial protein groups lower than 1800 were not included for further analysis. The resulting dataset was processed with the MetaLab 2.3 application to build a sample specific database (SS-DB) from the integrated gene catalog (IGC)-DB.² Taxonomic assignment to identify peptides was performed using the Unipept desktop version.³

Results

The average taxon-specific peptide distribution in the GM, especially at less specific taxonomic levels, did not show a striking difference between the groups at baseline. At the species level, after 8 weeks of a catered diet there was a general reduction of Collinsella aerofaciens that was more marked in groups 2 and 3P than in the HHC in group 3C. Collinsella aerofaciens has been linked to TLR2 activation, pro-inflammatory responses, and CD.⁴ We also observed a continuous increase in Prevotella copri over time in CD patients ultimately resulting in similar patterns as seen in the household controls. P. copri has recently been recognized as an important biomarker for diet improvements in dysbiosis⁵. In particular, there was an increase of proteins associated with carbohydrate metabolic processes in P. copri in the CD patients over time. Large scale annotation of the metaproteins and their related functions is ongoing.

Conclusion

Evidence suggests that a catered high fiber, low fat diet induces a change in the GM of CD patients more than in healthy subjects. The ability to compare the effect of a diet intervention in CD patients versus matched household controls will give additional power to understanding how diet can be used to manipulate the microbiome in the context of dysbiosis.

References

1) Levi Mortera et al. - International Journal of Molecular Science (2022) 23 (24), 15982; 2) Cheng et al. – Microbiome (2017), 5 (1), 157; 3) Verschaffelt et al. – Journal of Proteome Research (2021), 20 (4), 2083-2088; 4) Kwon J. et al. J Am Chem Soc. 2023 Apr 5; 145(13): 7071–7074; 5) Precup & Vodnar - British Journal of Nutrition (2019), 122, 131-140

Introduction

Gastric cancer (GC) is a leading cause of cancer-related deaths worldwide, ranking fourth in terms of mortality and fifth in terms of incidence, according to the 2020 GLOBOCAN report (1). Early detection of preneoplastic conditions such as gastric atrophy and intestinal metaplasia is crucial to reduce GC mortality (2). Moreover, its pathogenesis is a multifactorial process that is influenced by environmental and genetic factors. European guidelines (3) suggest shortening the interval of follow-up in patients with a family history. However, it is a weak recommendation with a low quality of evidence, as evidence regarding familiarity for GC and its related preneoplastic conditions is lacking.

Aims & Methods

To evaluate the risk of GC and preneoplastic conditions and lesions, including gastric atrophy, intestinal metaplasia, and dysplasia, in first-degree relatives for GC patients.
We conducted a systematic review and meta-analysis of case-control studies published on MEDLINE (PubMed and Embase) until November 2022. The primary outcome was the risk of GC in first-degree relatives for GC patients. The secondary findings were the risk of preneoplastic conditions and dysplasia in these patients. Two independent reviewers blindly performed the systematic review and data extraction. The disagreements were resolved through discussion. Homogeneity of effects across studies quantified by I². Odds ratio (OR) and 95% confidence intervals (CIs) were expressed using random effects models.

Results

Of the 1642 studies initially found, 18 studies met the inclusion criteria for GC, and 6 studies were included for preneoplastic conditions. The pooled analysis included a total of 59490 patients for the risk of GC and 4463 patients for the risk of preneoplastic conditions. The results showed a significantly increased risk of GC in first-degree relatives of GC patients (OR = 3.034; 95%CI 2.395 to 3.843; p <.001; I² 85.66%, 95%CI 78.73 to 90.33, p<.001). The risk of gastric atrophy was also significantly increased (OR = 3.812; 95%CI 1.674 to 8.682; p <.001, I² 78,26%, 95%CI 41.41 to 91.93; p = .003). However, the risk of intestinal metaplasia was not significant (OR = 1.207; 95%CI 0.937 to 1.555, p = .15). Furthermore, the risk of gastric dysplasia was found to be significant (OR = 5.480; 95%CI 1.054 to 28.482, p = .043, I² 80.34%, 95%CI 48.18 to 92.55 p = .002).

Conclusion

Our meta-analysis showed that the risk of GC and preneoplastic conditions and lesions, including gastric atrophy and dysplasia, is significantly increased in first-degree relatives for GC patients, even if a significant heterogeneity between studies was found. These findings highlighted the importance of identifying individuals at high risk to facilitate early detection and treatment of preneoplastic conditions, which could potentially reduce the burden of GC.

References

1. Sung, H., Ferlay, J., Siegel, R. L., Laversanne, M., Soerjomataram, I., Jemal, A., & Bray, F. (2021). Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA: a cancer journal for clinicians, 71(3), 209-249.
2. Pimentel-Nunes, P., Libânio, D., Marcos-Pinto, R., Areia, M., Leja, M., Esposito, G., ... & Dinis-Ribeiro, M. (2019). Management of epithelial precancerous conditions and lesions in the stomach (maps II): European Society of gastrointestinal endoscopy (ESGE), European Helicobacter and microbiota Study Group (EHMSG), European Society of pathology (ESP), and Sociedade Portuguesa de Endoscopia Digestiva (SPED) guideline update 2019. Endoscopy, 51(04), 365-388.
3. Yaghoobi, M., Bijarchi, R., & Narod, S. A. (2010). Family history and the risk of gastric cancer. British journal of cancer, 102(2), 237-242.

Introduction

Genetic predisposition to accumulate fat by carrying risk alleles of PNPLA3, TM6SF2 and HSD17B13, has been shown to influence the probability of developing cirrhosis and hepatocellular carcinoma (HCC) in several liver diseases characterized by hepatic steatosis including non-alcoholic steatohepatitis, chronic hepatitis C and alcoholic liver disease. Whether these variants have any role in the progression of chronic hepatitis B (CHB) disease, without hepatic steatosis, remains unknown.

Aims & Methods

In this cross-sectional case-control study, we determined PNPLA3 rs738409, TM6SF2 rs58542926, and HSD17B13 rs72613567 variants in a cohort of 148 healthy controls, 91 CHB (57 cirrhotic and 34 non-cirrhotic), and 84 CHB-related HCC patients from a tertiary center. Associations between control and case groups with the alleles and genotypes were investigated using logistic regression analyses, and adjustment for age and sex was applied. Survival analyses were performed using Kaplan-Meier Curves with the log-rank test in the CHB-related HCC cohort.

Results

The genotype and allelic distribution of PNPLA3, TM6SF2 and HSD17B13 were not different between healthy controls, CHB, cirrhosis and HCC groups. No genotype or allele, including the haplotype analysis, was found to be associated with susceptibility to CHB and increased risk for cirrhosis or HCC. Survival analysis revealed that none of the three variants has any influence on overall survival in patients with CHB-related HCC.

Conclusion

Our findings demonstrated that PNPLA3, TM6SF2, and HSD17B13 genetic variants, known for modulating liver fat and disease progression in hepatic steatosis, have no association with disease progression in patients with CHB and survival in CHB-related HCC.

References

1. Abul-Husn NS, Cheng X, Li AH, et al. A Protein-Truncating HSD17B13 Variant and Protection from Chronic Liver Disease. N Engl J Med. 2018 Mar 22;378(12):1096-1106.
2. Gellert-Kristensen H, Richardson TG, Davey Smith G, et al. Combined Effect of PNPLA3, TM6SF2, and HSD17B13 Variants on Risk of Cirrhosis and Hepatocellular Carcinoma in the General Population. Hepatology. 2020 Sep;72(3):845-856.
3. Kang Q, Xu J, Luo H, et al. Evaluation of the association of a variant in PNPLA3 and TM6SF2 with fibrosis progression in patients with chronic hepatitis C infection after eradication: A retrospective study. Gene. 2022 Apr 30;820:146235.
4. Stickel F, Buch S, Nischalke HD, et al. Genetic variants in PNPLA3 and TM6SF2 predispose to the development of hepatocellular carcinoma in individuals with alcohol-related cirrhosis. Am J Gastroenterol. 2018 Oct;113(10):1475-1483.

Introduction

Irritable bowel syndrome (IBS) is often associated with gastrointestinal motility disorders, these being modulated by the endogenous serotonin system through many serotonin receptor subtypes (Guzel, 2022). Saccharomyces boulardii CNCM I-745 is a probiotic yeast with antidiarrheal properties (Szajewska, 2020) and efficacy in IBS clinical studies (McFarland, 2021). It has been shown to inhibit gut motility through upregulation of the intestinal serotonin transporter (Gu, 2022). The present study explored the possible involvement of serotoninergic receptor subtypes in this effect in a rat isolated ileum model.

Aims & Methods

Isolated ileum from adult Wistar rat is incubated in organ bath (20 mL) containing Krebs (oxygenated with 95% O₂ and 5% CO₂ at 37°C) according to Briejer (1997). Contractions of the ileum are measured by an isotonic force transducer (Ugo Basile). Cumulative administration of serotonin or specific agonists induce concentration-dependent contractions. Serotonin antagonists or lyophilised S. boulardii are added into the bath 10 minutes before the various agonists. EC₅₀ values determination from concentration-response curves and comparisons between treatments are made by GraphPad Prism.

Results

Serotonin induced a concentration-dependent contraction of the ileum with an EC₅₀ value of 0.074 µM. This effect was inhibited by 5-HT_1A WAY100635, 5-HT_2A ketanserin and 5-HT₄ GR113808 antagonists, but not 5-HT_2C SB242084, 5-HT₃ tropisetron and ondansetron or 5-HT₇ SB266970 antagonists. S. boulardii at 0.05-0.15-0.5-1.5 mg/mL shifted the serotonin concentration-response curve to the right, with EC₅₀ values of 0.13-0.19-1.0-2.1 µM respectively, suggesting an inhibitory effect. S. boulardii also inhibited contraction induced by 5-HT_1A 5-carboxamidotryptamine or 5-HT_2A/2B/2C α-methyl-5-HT agonists. 1.5 mg/mL of S. boulardii significantly increased EC₅₀ values of 5-carboxamidotryptamine (0.15 µM) and α-methyl-5-HT (0.27 µM) to 2.4 and 1.3 µM, respectively.

Conclusion

These results show that in our model, the effects of S. boulardii CNCM I-745 on intestinal motility are mainly mediated by serotonin 5-HT_1A and 5-HT_2A/2B/2C receptor subtypes. Additional studies are currently needed to better explain S. boulardii mechanism of action in IBS motility disorders.

References

Briejer et al., 1997, Neurogastroenterol. Mot., 9, 231-237.
Gu et al., 2022, Pharmacol. Res., 181, 106291.
Guzel and Mirowska-Guzel., 2022, Molecules, 27, 1680.
McFarland et al., 2021, EClinicalMedicine, 41, 101154.
Szajewska et al., 2020, Aliment. Phamacol. Ther., 51, 678-688.

Disclosure

I am an employee of Biocodex

Introduction

Endoscopic mucosal resection has been associated with lesion recurrence in 16%-27% of cases. Guidelines recommend endoscopic follow-up but it is unclear if endoscopic assessment has to include biopsies.

Aims & Methods

This study aims to evaluate the recurrence prediction of white light endoscopy (WLE) and narrow band imaging (NBI) in the assessment of colorectal mucosal resection scar. We performed a systematic review in PubMed, Embase, Cochrane and Web of Science databases, searching for studies comparing WLE and NBI. Statistical analysis included data pooling and heterogeneity testing. Quality of the included studies was assessed by Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2).

Results

The meta-analysis included 5 studies and 798 mucosal resections. The pooled sensitivity and specificity and AUC for WLE were 80.9% (95% CI 71.8% to 87.5%), 95.6% (95% CI 92.0% to 97.6%) and 0.917 (95% CI 0.885 to 0.972), respectively. The pooled sensitivity and specificity and AUC for NBI were 92.1% (95% CI 87.3 to 95.2%), 94.1% (95% CI 91.9% to 95.7%) and 0.935 (95% CI 0.772 to 0.972), respectively. There was no difference in AUC of WLE and NBI (p=0.633).

Conclusion

Our study demonstrates a high sensitivity, specificity and accuracy for endoscopic diagnosis of recurrent lesions after colorectal mucosal resection, specially with NBI. In all cases of low confidence assessment, biopsy is required.

References

1. Desomer L, Tutticci N, Tate D, Williams S, McLeod D, Bourke M. A standardized imaging protocol is accurate in detecting recurrence after EMR. Gastrointest Endosc. 2017 Mar;85(3):518–26.
2. Kandel P, Brand EC, Pelt J, Ball CT, Chen WC, Bouras EP, et al. Endoscopic scar assessment after colorectal endoscopic mucosal resection scars: when is biopsy necessary (EMR Scar Assessment Project for Endoscope (ESCAPE) trial). Gut. 2019 Sep;68(9):1633–41.
3. Pu L, Chiam K, Yamamura T, Nakamura M, Berzin T, Mir F, et al. Narrow-band imaging for scar (NBI-SCAR) classification: From conception to multicenter validation. J Gastroenterol Hepatol. 2019 Sep;34:227–8.
4. Riu Pons F, Andreu M, Gimeno Beltran J, Álvarez-Gonzalez MA, Seoane Urgorri A, Dedeu JM, et al. Narrow band imaging and white light endoscopy in the characterization of a polypectomy scar: A single-blind observational study. World J Gastroenterol. 2018 Dec 7;24(45):5179–88.

Introduction

Chronic intestinal pseudo-obstruction (CIPO) is a rare syndrome characterized by severe gastrointestinal (GI) dysmotility that mimics a GI obstruction in the absence of any detectable mechanical cause [1]. CIPO can be classified as primary (e.g. linked to a genetic disorder), secondary (to a wide array of conditions) or idiopathic. We recently demonstrated that jejunal longitudinal muscle layer abnormalities associated to vascular changes can contribute to GI dysfunction in a genetically driven form of CIPO [2].

Aims & Methods

The aim of this study was to investigate the presence of jejunal longitudinal muscle layer atrophy and vascular alterations in idiopathic forms of CIPO. Full thickness jejunal biopsies were collected from n=27 well characterized patients and n=10 controls. Formalin fixed-paraffin embedded (FFPE) tissue sections were stained with Sirius Red/Fast Green-collagen-assay to measure longitudinal muscle layer thickness and to spectrophotometrically determine fibrosis. FFPE full thickness jejunal sections were also stained with orcein to quantify and measure blood vessel size. The blood vessels were subdivided in >300µm (large), 300-101µm (medium), 100-51µm (small) and <50µm (very small). Frozen full-thickness tissue was used to assess by western blot the expression of HIF-1α as marker of hypoxia and of thymidine phosphorylase (TP), as this enzyme is involved in the pathophysiology of angiogenesis and is found absent in previously documented CIPO secondary to a genetic disorder [3]. Finally, jejunal muscle thickness was correlated with patients’ clinical data.

Results

Idiopathic CIPO patients showed 1.87 times (431.9±192.2 vs. 837.2±446.4 µm; P=0.0026) decreased thickness of the jejunal longitudinal muscle layer and a higher fibrosis index compared to controls. Idiopathic CIPO patients displayed a lower vascular area with more submucosal vessels/mm²vs. controls; vessels <50 µm increased at the expense of medium and large vessels. Moreover, the jejunum of idiopathic CIPO patients presented an increased HIF-1α expression indicative of hypoxia and a lower TP enzyme expression suggesting alterations in local angiogenesis. Finally, from a clinical standpoint, the jejunal muscle thickness was inversely correlated to the number of sub-obstructive episodes, abdominal distension and pain.

Conclusion

In addition to genetic CIPO, also idiopathic forms of this syndrome exhibit significant changes, i.e. muscular atrophy and fibrosis associated with major vascular remodeling likely dependent to hypoxia and a lower local TP protein expression. These data are clinically relevant as reduced muscular thickness correlates with worse clinical phenotypes of idiopathic CIPO.

References

[1] Downes, T.J.; Cheruvu, M.S.; Karunaratne, T.B.; De Giorgio, R.; Farmer, A.D. Pathophysiology, Diagnosis, and Management of Chronic Intestinal Pseudo-Obstruction. J Clin Gastroenterol 2018, 52, 477-489, doi:10.1097/MCG.0000000000001047.
[2] Boschetti, E.; D'Angelo, R.; Tardio, M.L.; Costa, R.; Giordano, C.; Accarino, A.; Malagelada, C.; Clavenzani, P.; Tugnoli, V.; Caio, G.; et al. Evidence of enteric angiopathy and neuromuscular hypoxia in patients with mitochondrial neurogastrointestinal encephalomyopathy. Am J Physiol Gastrointest Liver Physiol 2021, 320, G768-G779, doi:10.1152/ajpgi.00047.2021.
[3] Hirano, M.; Carelli, V.; De Giorgio, R.; Pironi, L.; Accarino, A.; Cenacchi, G.; D'Alessandro, R.; Filosto, M.; Martí, R.; Nonino, F.; et al. Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE): Position paper on diagnosis, prognosis, and treatment by the MNGIE International Network. J Inherit Metab Dis 2021, 44, 376-387, doi:10.1002/jimd.12300.