Technology assessment in the Coronary Artery Surgery Study

Human bile contains microRNA-laden extracellular vesicles that can be used for cholangiocarcinoma diagnosis

Cholangiocarcinoma (CCA) presents significant diagnostic challenges, resulting in late patient diagnosis and poor survival rates. Primary sclerosing cholangitis (PSC) patients pose a particularly difficult clinical dilemma because they harbor chronic biliary strictures that are difficult to distinguish from CCA. MicroRNAs (miRs) have recently emerged as a valuable class of diagnostic markers; however, thus far, neither extracellular vesicles (EVs) nor miRs within EVs have been investigated in human bile. We aimed to comprehensively characterize human biliary EVs, including their miR content. We have established the presence of extracellular vesicles in human bile. In addition, we have demonstrated that human biliary EVs contain abundant miR species, which are stable and therefore amenable to the development of disease marker panels. Furthermore, we have characterized the protein content, size, numbers, and size distribution of human biliary EVs. Utilizing multivariate organization of combinatorial alterations (MOCA), we defined a novel biliary vesicle miR-based panel for CCA diagnosis that demonstrated a sensitivity of 67% and specificity of 96%. Importantly, our control group contained 13 PSC patients, 16 with biliary obstruction of varying etiologies (including benign biliary stricture, papillary stenosis, choledocholithiasis, extrinsic compression from pancreatic cysts, and cholangitis), and 3 with bile leak syndromes. Clinically, these types of patients present with a biliary obstructive clinical picture that could be confused with CCA.

CONCLUSION

These findings establish the importance of using extracellular vesicles, rather than whole bile, for developing miR-based disease markers in bile. Finally, we report on the development of a novel bile-based CCA diagnostic panel that is stable, reproducible, and has potential clinical utility.

Uses of clinical databases

Clinical databases consist of observational data collected on patients who meet specific criteria. The uses of these databases depend on whether the observations are drawn from a single institution, multiple clinical centers, or are population-based. Single institution databases frequently are used to profile patient accrual. In cases of rare diseases or unusual procedures, multicenter databases are required to amass sufficient information for study. Multicenter databases can be used to address issues related to intercenter variation and to develop statistical models to predict outcome based on prognostic factors. Population-based databases are required to assess incidence, prevalence, and mortality rates of disease. Although the inferences that can be drawn from observational data are limited by selection bias, clinical databases are valuable tools in planning clinical research. Clearly, however, resources are required to develop and maintain clinical databases. In an era when much research funding is directed at hypothesis-driven research, the importance of these clinical databases in developing clinical research hypotheses should not be overlooked.