Mucosal microbiome associates with progression to gastric cancer

Background & Aims: Dysbiosis is associated with gastric cancer (GC) development. However, no longitudinal study was carried out to identify key bacteria that could predict for GC progression. Here, we aimed to investigate changes in bacterial metagenome prior to GC and develop a microbiome-based predictive model to accurately classify patients at risk of GC.

Methods: Bacterial 16S rDNA was sequenced from 89 gastric antral biopsies obtained from 43 participants. This study was nested in a prospective, longitudinal study, whereby study participants underwent screening gastroscopy, with further 1-2 yearly surveillance gastroscopies for at least 5 years. Putative bacterial taxonomic and functional features associated with GC carcinogenesis were identified by comparing between controls, patients with gastric intestinal metaplasia (IM) and patients with early gastric neoplasia (EGN).

Results: Patients with EGN had enrichment of Proteobacteria (in particular Proteus genus) and depletion of Bacteroidetes (in particular S24-7 family) in their gastric mucosa. Sequencing identified more patients with Helicobacter pylori compared to histopathological assessment, while H. pylori was also significantly enriched in EGN. Furthermore, a total of 261 functional features, attributing to 97 KEGG pathways were differentially abundant at baseline between patients who subsequent developed EGN (n = 13/39) and those who did not. At the same time, a constellation of six microbial taxonomic features present at baseline, provided the highest classifying power for subsequent EGN (AUC = 0.82).

Conclusion: Our study highlights early microbial changes associated with GC carcinogenesis, suggesting a potential role for prospective microbiome surveillance for GC.

Rising prevalence of colonic diverticulosis in a westernized multi-ethnic Asian community

BACKGROUND AND AIM

Singapore is a multi-ethnic country that has undergone rapid development over the last few decades, with increasing influence of western culture, and faces an aging population. Previously, a varying prevalence of colonic diverticulosis (CD) was reported by a few small studies. This study aims to evaluate the prevalence of CD in Singapore and identify associations with common gastrointestinal symptoms and risk factors.

METHODS

We reviewed retrospective data of 20 395 consecutive colonoscopies performed from 2006 to 2016 for presence of CD and indications of screening, diarrhea, constipation, and abdominal pain.

RESULTS

The prevalence of CD progressively increased from 2006 to 2016 (14.9% vs 23.9%, adjusted trend < 0.001), with an overall prevalence of 19.6%. Patients with CD were older and had higher body mass index (BMI). CD was significantly more prevalent in Chinese compared with Malay and Indian races (20.5% vs 18.9% vs 15.5%, P < 0.05), and in male patients compared with female patients (21.5% vs 17.6%, P < 0.05). Right-sided CD was more common than left-sided or pan diverticulosis (16.2% vs 8.3% vs 4.8%, P < 0.05). Age [odds ratio (OR), 1.060; 95% confidence interval (CI), 1.052-1.068], BMI (OR, 1.051; 95% CI, 1.028-1.075), male gender (OR, 1.317; 95% CI, 1.084-1.600), and abdominal pain (OR, 1.409; 95% CI, 1.168-1.699) were positively associated, while constipation (OR, 0.566; 95% CI, 0.452-0.709) was negatively associated with CD.

CONCLUSION

The prevalence of CD in Singapore has progressively increased over the last decade and is associated with older age, higher BMI, and abdominal pain. These findings may provide insights for healthcare resource planning in the region.

Improvement in Non-alcoholic Fatty Liver Disease Score Correlates with Weight Loss in Obese Patients Undergoing Laparoscopic Sleeve Gastrectomy: a Two-Centre Study from an Asian Cohort

PURPOSE

Incidence of non-alcoholic fatty liver disease (NAFLD) is on the rise and is one of the most common causes of chronic liver disease worldwide. Obesity and metabolic syndrome are considered the most significant risk factors. Bariatric surgery is the only treatment modality in morbid obesity which allows long-term weight loss with improvement in associated co-morbid conditions. However, the effects of bariatric surgery on NAFLD are not well established. NAFLD fibrosis score (NFS) is a validated non-invasive scoring system used to assess advanced fibrosis. We used the NFS to analyse the impact of weight loss on NAFLD following sleeve gastrectomy.

MATERIALS AND METHODS

174 patients who underwent bariatric surgery between 2010 and 2016 were retrospectively reviewed. Multivariate analysis was performed using pre-operative patient characteristics, biochemical markers and TANITA body analysis measurements to determine significant risk factors for NFS > 0.675. Additionally, the NFS was calculated at 6 months, 1 year and 2 years post-operatively to determine correlation with weight loss.

RESULTS

Pre-operatively, 13.8% of our patients had significant fibrosis by NFS. Mean change in NFS was - 0.46 ± 1.02, - 0.55 ± 0.98 and - 0.55 ± 1.12 at 6 months, 1 year and 2 years respectively. This was significantly correlated with percent of total weight loss with R coefficients of 0.253, 0.292 and 0.274 respectively (P < 0.05). 79.2% of patients with NFS > 0.675 achieved resolution by 2 years post-operatively.

CONCLUSION

Based on our study, we conclude that sleeve gastrectomy may be a viable treatment option for management of NAFLD in the obese.

Asian consensus on the relationship between obesity and gastrointestinal and liver diseases

The incidence of obesity is increasing in Asia, with implications on gastrointestinal (GI) and liver diseases. The Gut and Obesity in Asia Workgroup comprises regional experts with the aim of studying relationship between obesity and the GI and liver diseases in Asia. Through literature review and the modified Delphi process, consensus statements examining the impact of obesity on esophageal, gastric, pancreatic, colorectal, and liver diseases, exploring relationship between gut microbiome and obesity, and assessing obesity therapies have been produced by the Gut and Obesity in Asia Workgroup. Sixteen experts participated with 9/15 statements having strong consensus (>80% agreement). The prevalence of obesity in Asia is increasing (100% percentage agreement in brackets), and this increased prevalence of obesity will result in a greater burden of obesity-related GI and liver diseases (93.8%). There was consensus that obesity increases the risk of gastric cancer (75%) and colorectal neoplasia (87.5%). Obesity was also associated with Barrett's esophagus and esophageal adenocarcinoma (66.7%) and pancreatic cancer (66.7%) in Asia. The prevalence of non-alcoholic fatty liver disease (NAFLD) in Asia is on the rise (100%), and the risk of NAFLD in Asia (100%) is increased by obesity. Obesity is a risk factor for the development of hepatocellular carcinoma (93.8%). Regarding therapy, it was agreed that bariatric surgery was an effective treatment modality for obesity (93.8%) but there was less agreement on its benefit for NAFLD (62.5%). These experts' consensus on obesity and GI diseases in Asia forms the basis for further research, and its translation into addressing this emerging issue.