Modulation of the Gut Microbiome to Improve Clinical Outcomes in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related mortality worldwide. Recently, the gut microbiota has been shown to be closely linked to modulation of the immune and inflammatory responses, hence its potential as a therapeutic target. Although still under intense investigation, there exists a 'gut-liver axis' that links changes in the gut to the liver. In this regard, composition of gut microbiota and related metabolites, such as bile acids and short-chain fatty acids, have been shown to orchestrate key immune-metabolic events in liver disease and liver cancer. As hepatic immune cells are important determinants of antitumor responses, it is now increasingly recognized that the gut-liver axis plays a key role in influencing the intrahepatic immune response in HCC to favor a pro- or antitumor immune milieu. Hence, modulation of gut microbiota is potentially an attractive option to reinvigorate the antitumor responses. In this regard, promising evidence from melanoma preclinical and clinical studies has demonstrated the efficacy of gut-based intervention in reinvigorating the antitumor responses and improving responses to immunotherapy. However, the role of gut-based interventions as a therapeutic option in HCC remains to be elucidated. This review details how the gut microbiota and bacterial metabolites affect gut barrier function and ultimately immune response in HCC and raises the question of the potential of gut-based interventions as an adjunct therapy for patients with HCC receiving immunotherapy.

Refining a Protocol for Faecal Microbiota Engraftment in Animal Models After Successful Antibiotic-Induced Gut Decontamination.

BACKGROUND: There is mounting evidence for the therapeutic use of faecal microbiota transplant (FMT) in numerous chronic inflammatory diseases. Germ free mice are not always accessible for FMT research and hence alternative approaches using antibiotic depletion prior to FMT in animal studies are often used. Hence, there is a need for standardising gut microbiota depletion and FMT methodologies in animal studies. The aim of this study was to refine gut decontamination protocols prior to FMT engraftment and determine efficiency and stability of FMT engraftment over time. METHODS: Male C57BL/6J mice received an antibiotic cocktail consisting of ampicillin, vancomycin, neomycin, and metronidazole in drinking water for 21 days ad libitum. After antibiotic treatment, animals received either FMT or saline by weekly oral gavage for 3 weeks (FMT group or Sham group, respectively), and followed up for a further 5 weeks. At multiple timepoints throughout the model, stool samples were collected and subjected to bacterial culture, qPCR of bacterial DNA, and fluorescent in-situ hybridisation (FISH) to determine bacterial presence and load. Additionally, 16S rRNA sequencing of stool was used to confirm gut decontamination and subsequent FMT engraftment. RESULTS: Antibiotic treatment for 7 days was most effective in gut decontamination, as evidenced by absence of bacteria observed in culture, and reduced bacterial concentration, as determined by FISH as well as qPCR. Continued antibiotic administration had no further efficacy on gut decontamination from days 7 to 21. Following gut decontamination, 3 weekly doses of FMT was sufficient for the successful engraftment of donor microbiota in animals. The recolonised animal gut microbiota was similar in composition to the donor sample, and significantly different from the Sham controls as assessed by 16S rRNA sequencing. Importantly, this similarity in composition to the donor sample persisted for 5 weeks following the final FMT dose. CONCLUSIONS: Our results showed that 7 days of broad-spectrum antibiotics in drinking water followed by 3 weekly doses of FMT provides a simple, reliable, and cost-effective methodology for FMT in animal research.

Critical Assessment of Whole Genome and Viral Enrichment Shotgun Metagenome on the Characterization of Stool Total Virome in Hepatocellular Carcinoma Patients.

Viruses are the most abundant form of life on earth and play important roles in a broad range of ecosystems. Currently, two methods, whole genome shotgun metagenome (WGSM) and viral-like particle enriched metagenome (VLPM) sequencing, are widely applied to compare viruses in various environments. However, there is no critical assessment of their performance in recovering viruses and biological interpretation in comparative viral metagenomic studies. To fill this gap, we applied the two methods to investigate the stool virome in hepatocellular carcinoma (HCC) patients and healthy controls. Both WGSM and VLPM methods can capture the major diversity patterns of alpha and beta diversities and identify the altered viral profiles in the HCC stool samples compared with healthy controls. Viral signatures identified by both methods showed reductions of Faecalibacterium virus Taranis in HCC patients' stool. Ultra-deep sequencing recovered more viruses in both methods, however, generally, 3 or 5 Gb were sufficient to capture the non-fragmented long viral contigs. More lytic viruses were detected than lysogenetic viruses in both methods, and the VLPM can detect the RNA viruses. Using both methods would identify shared and specific viral signatures and would capture different parts of the total virome.

Gut microbiota impact on the peripheral immune response in non-alcoholic fatty liver disease related hepatocellular carcinoma.

The gut microbiota is reported to modulate the immune response in hepatocellular carcinoma (HCC). Here, we employ metagenomic and metabolomic studies to characterise gut microbiota in patients with non-alcoholic fatty liver disease (NAFLD) related cirrhosis, with or without HCC, and evaluate its effect on the peripheral immune response in an ex vivo model. We find that dysbiosis characterises the microbiota of patients with NAFLD-cirrhosis, with compositional and functional shifts occurring with HCC development. Gene function of the microbiota in NAFLD-HCC supports short chain fatty acid production, and this is confirmed by metabolomic studies. Ex vivo studies show that bacterial extracts from the NAFLD-HCC microbiota, but not from the control groups, elicit a T cell immunosuppressive phenotype, characterised by expansion of regulatory T cells and attenuation of CD8 + T cells. Our study suggest that the gut microbiota in NAFLD-HCC is characterised by a distinctive microbiome/metabolomic profile, and can modulate the peripheral immune response.

Non-alcoholic fatty liver disease: a review of epidemiology, risk factors, diagnosis and management.

Due to the rising prevalence of obesity and type II diabetes mellitus, non-alcoholic fatty liver disease is becoming the leading cause of chronic liver disease in the Western world. In some patients, simple steatosis can result in non-alcoholic steatohepatitis which over time can lead to liver cirrhosis and its associated sequelae, including hepatocellular carcinoma. Early identification and management of patients at risk with intensive dietary and lifestyle modification are essential to prevent the development of advanced liver disease and its complications. In this review, we will discuss the epidemiology of non-alcoholic fatty liver disease, pathogenesis, diagnosis, management and surveillance strategies to offset the morbidity and mortality of this disease, as well as liver and non-liver-related complications.

The interobserver agreement of optical features used to differentiate benign from neoplastic biliary lesions assessed at balloon-assisted cholangioscopy.

BACKGROUND AND AIM: Balloon-assisted cholangioscopy allows mucosal assessment of the biliary tree with pediatric endoscopes. No validated optical criteria exist to differentiate benign from neoplastic biliary lesions. We aimed to identify, validate, and revalidate optical features differentiating benign from neoplastic biliary lesions. Furthermore, we aimed to determine whether cholangioscopic appearance allows endoscopists to accurately differentiate benign from neoplastic biliary lesions. METHODS: Baseline: from 44 de-identified balloon-assisted cholangioscopy videos, a blinded investigator analyzed potential optical features distinguishing benign from neoplastic biliary lesions. VALIDATION: during the initial "teaching phase," 20 endoscopists viewed video clips of 11 optical features identified in the baseline study. At the subsequent "test phase," 20 further video clips were assessed by the endoscopists blinded to clinical details and questionnaires completed for the presence or absence of optical features, favored diagnosis and diagnostic confidence. Revalidation: The six identified optical features from the validation study with at least moderate agreement were revalidated the same way 12 months later assessing 20 new lesions. RESULTS: Baseline: 11 optical features were found to differentiate benign from neoplastic biliary lesions. Validation and revalidation: six optical features demonstrated at least moderate interobserver agreement (irregular margin, dark mucosa, adherent mucous, papillary projections, tubular, or branched/disorganized surface structures). Endoscopists correctly diagnosed lesions as benign in 89% and neoplastic in 83%. When highly confident, endoscopists correctly diagnosed 96% of benign and 87% neoplastic lesions. CONCLUSIONS: Six features were validated and revalidated to differentiate benign from neoplastic biliary lesions. When highly confident with a diagnosis, endoscopists usually differentiate benign from neoplastic biliary lesions.

Advances in the Endoscopic Management of Obesity.

Obesity has become a worldwide epidemic with significant impact on quality of life, morbidity, and mortality rates. Over the past two decades, bariatric surgery has established itself as the most effective and durable treatment for patients with obesity and its associated comorbidities. However, despite the use of minimally invasive techniques, bariatric surgery is associated with complications in approximately 15% of patients, has a substantial cost, and is used by only 1% of patients who are eligible. Therefore, there is a need for effective minimally invasive therapies, which will be utilized by the large proportion of obese patients who are in desperate need of treatment but are not receiving any. Endoscopic approaches to the management of obesity have been developed, with the aim of delivering more effective, durable, and safer methods of weight reduction. In this paper, we review currently available and future endoscopic therapies that will likely join the armamentarium used in the management of obesity.

Efficacy and safety of pneumatic dilatation for achalasia in the treatment of post-myotomy symptom relapse.

OBJECTIVES: There is no consensus on how best to treat symptom recurrence following previous therapy with Heller myotomy. Our aim was to determine the safety and the short and long-term efficacy of pneumatic dilatation to treat symptomatic recurrence in patients previously treated with Heller myotomy for idiopathic achalasia. METHODS: We identified 27 eligible patients treated with pneumatic dilatation, for symptom recurrence following Heller myotomy as their initial or secondary treatment, from a prospectively acquired database of 450 patients with a diagnosis of achalasia seen between 1995 and 2010. Our treatment protocol involved sequential, graded pneumatic dilatations (30-35-40 mm) over a 2-6 week period until an initial therapeutic response was achieved. The subsequent relapse rate, defined as the need for any subsequent therapy, was determined. Relapsers were offered further pneumatic dilatation "on demand". A cross-sectional analysis was also performed using a validated achalasia severity questionnaire to determine the overall long-term remission rate. RESULTS: Of 27 eligible patients, 25 (93%) complied with the institutional dilatation protocol. The two drop-outs did so after the initial 30 mm dilatation and were deemed treatment failures. One additional patient did not respond despite protocol compliance. Therefore, 24 of 27 (89%) patients were responders on intention to treat analysis at 12 months, while the per protocol response rate was 24 of 25 (96%). Among the 24 responders 16, 25, and 42% relapsed at 2, 3 and 4 years, respectively. Overall long-term remission, with on demand dilatations as required, was 95% (median follow-up 30 months). There were no perforations in a total of 50 dilatations in 27 patients. CONCLUSIONS: In treating symptom recurrence, following prior Heller myotomy, pneumatic dilatation is safe and yields an excellent short-term response rate. Although the long-term relapse rate is substantial, subsequent on demand pneumatic dilatation in this population is highly effective with a long-term remission rate of 95%. These data also highlight the need to keep these patients under long-term review.

Prevalence of adenomas and sessile serrated adenomas in Chinese compared with Caucasians.

BACKGROUND AND AIMS: Colonic adenomas and sessile serrated adenomas (SSA) are the most common premalignant polyps identified at colonoscopy. This study compares the prevalence of neoplastic polyps in Chinese and Caucasians in a general gastroenterology outpatient practice in Australia. METHODS: This study included consecutive unselected colonoscopies performed for standard clinical indications by a single endoscopist (JMH). All polyps detected were measured, resected, and sent for histopathology. The prevalence of adenomas, advanced adenomas, SSA, and cancer in the Chinese and Caucasian cohorts were compared. Advanced adenomas were defined as adenomas > 10 mm, villous histology, or high-grade dysplasia. RESULTS: The study included 346 Chinese and 654 Caucasians. There was no significant difference in the baseline characteristics including age, gender, and indications of colonoscopy, although Chinese were more likely to present with rectal bleeding (22.8% vs 15.9%, P = 0.01). The prevalence of adenomatous polyps was similar in both Caucasians (34.3%) and Chinese (35.3%). However, advanced adenomas were more significantly common in Caucasians (11.3%) compared with Chinese (4.6%) (P < 0.001). SSA was rare in Chinese (2%) but present more frequently in Caucasians (7%) (P = 0.001). Multivariate analysis showed that Caucasian ethnicity (odds ratio 2.4, 95% confidence interval 1.6-3.6) and the presence of SSA (odds ratio 4.4, 95% confidence interval 2.3-8.6) were independent predictors for the detection of an advanced adenoma. CONCLUSIONS: The prevalence of significant colorectal lesions, including advanced adenomas, large adenomas, and SSA, were lower in Chinese compared with Caucasians. These findings may influence the guidelines for colonic cancer screening in Chinese populations.