Citations

INTRODUCTION: Primary sclerosing cholangitis (PSC) is a chronic, fibroinflammatory, cholestatic liver disease of unknown etiopathogenesis which is recognized as a major risk factor for cholangiocarcinoma (CCA). We aimed to investigate the roles of the biliary and intestinal microflora in the inflammatory process of PSC and to determine if the microflora is associated with progression to CCA. METHODS: We studied the bile and stool microbiomes in samples obtained from patients with PSC (31 stool and 35 bile samples), sporadic CCA (11 stool and 26 bile samples), and PSC coexisting with CCA (16 stool and bile 17 samples). Control bile was obtained from patients with cholelithiasis or choledocholithiasis (n = 17). DNA extraction was followed by amplification and high-throughput next generation sequencing (MiSeq) of the 16S rDNA (V3-V5) region to identify the microbiota present. We performed: 1. analysis of the stool microbiome between PSC and CCA patients; 2. analysis of the biliary microbiome in PSC and CCA patients; 3. comparison of the biliary microbiome collected before and after biliary stent placement. RESULTS: Although bile samples from study patients had significantly lower sequencing depths than stool, their sequencing depths were much higher than bile from negative controls. The microbiomes of stool and bile samples from the same patients were significantly correlated ( P = 0.022). CCA bile samples had significant difference of alpha diversity from control bile samples with less Streptococcaceae and Desulfovibrionaceae (FDR < 10%) than PSC whereas no significant change of stool microbiome was identified between CCA and PSC. Fusobacterium and Gemella were correlated to PSC duration. An increased abundance of Fusobacteria after stent placement was revealed. Fusobacteria, which is inflammation-promoting, was also increased with the number of stents in the bile duct. CONCLUSION: Our study suggests that the bile microbiome is potentially a more distinctive biomarker than the stool microbiome for PSC and CCA development. There is increased inhabitance of inflammation-promoting bacteria in the bile of CCA patients and after biliary stent placement. Increased PSC duration also increases the microbial burden in the bile, which may also promote CCA development. We further detected specific bile microbes statistically associated with CCA or stent presence in the bile ducts, which raises the possibility of their role in the CCA progression or stent obstruction. Additional analyses with more samples are needed.

AbstractBackground and AimTumor genotyping may allow for improved prognostication and targeted therapy for pancreatic ductal adenocarcinoma (PDAC). We aimed to compare endoscopic ultrasonography (EUS) with fine needle aspiration (FNA) to fine needle biopsy (FNB) for obtaining sufficient tissue for genomic analysis and theranostic potential.MethodsA retrospective cohort study of patients that underwent EUS‐FNA or EUS‐FNB with either positive or suspicious cytology for PDAC between March 2016 and December 2017. Demographic, procedural, and cytology data were recorded. Genetic alterations were recorded, and Kaplan–Meier survival curves were calculated.ResultsThe study included 167 patients: 145 patients had FNA and 22 patients underwent FNB. Overall, 117 samples (70.1%) were sufficient for targeted next‐generation sequencing. FNB resulted in a higher proportion of patients with sufficient samples compared with FNA (90.9% vs 66.9%; P = 0.02). In multivariable modeling, only FNB (odds ratio 4.95, 95% confidence interval 1.11–22.05, P = 0.04) was associated with sufficient sampling for genomic testing. FNB was more likely to obtain sufficient tissue from tumors ≤ 3 cm (100% vs 68.4%, P = 0.017) and tumors located in the head/neck of the pancreas (100% vs 63.1%, P = 0.03) compared with FNA. The most commonly identified alterations were in KRAS (88%), TP53 (68%), and SMAD4 (16%).ConclusionsEndoscopic ultrasonography can reliably obtain sufficient tissue from PDAC for targeted genomic sequencing for prognostication and theranostics. FNB should be considered when tumor genotyping is requested, especially for tumors ≤ 3 cm or tumors located in the head/neck of the pancreas.

AbstractThe diagnosis of malignant biliary strictures remains problematic, especially in the perihilar region and in primary sclerosing cholangitis (PSC). Conventional cytology obtained during endoscopic retrograde cholangiography (ERC)-guided brushings of biliary strictures is suboptimal due to limited sensitivity, albeit it remains the gold standard with a high specificity. Emerging technologies are being developed and validated to address this pressing unmet patient need. Such technologies include enhanced visualization of the biliary tree by cholangioscopy, intraductal ultrasound, and confocal laser endomicroscopy. Conventional cytology can be aided by employing complementary and advanced cytologic techniques such as fluorescent in situ hybridization (FISH), and this technique should be widely adapted. Interrogation of bile and serum by examining extracellular vesicle number and cargo, and exploiting next-generation sequencing and proteomic technologies, is also being explored. Examination of circulating cell-free deoxyribonucleic acid (cfDNA) for differentially methylated regions is a promising test which is being rigorously validated. The special expertise required for these analyses has to date hampered their validation and adaptation. Herein, we will review these emerging technologies to inform the reader of the progress made and encourage further studies, as well as adaptation of validated approaches.