Review Articles, News & Views, Perspectives, Hypotheses, Analyses and Review in 2019

A new study provides mechanistic insight into the carcinogenic potential of human colonic mucosal microbial biofilms, confirming that both microbiota composition and organization along with the host inflammatory response are contributing factors to creating the ‘perfect storm’ in terms of colorectal carcinogenesis.

The hepatic consequence of metabolic syndrome and obesity, nonalcoholic fatty liver disease (NAFLD), underlies many cases of hepatocellular carcinoma (HCC). In this Review, the authors discuss NAFLD-associated HCC, including its epidemiology, key features that promote hepatocarcinogenesis and the management of HCC in patients with obesity.

Nonalcoholic fatty liver disease (NAFLD) was first described four decades ago, but it is increasingly important owing to its high prevalence in the general population. This Perspective provides an overview on the development of knowledge related to NAFLD, focusing on landmark findings.

The introduction of white light imaging capsule endoscopy has motivated research to improve its diagnostic capabilities through integration with other sensing modalities. In this Review, the authors summarize studies on non-white light imaging devices, such as those using optical coherence tomography, ultrasonography or biophysical measurements

Key hepatic functions are expressed non-uniformly across liver lobules, a phenomenon termed zonation. Here, Ben-Moshe and Itzkovitz discuss the principles of liver zonation, the intrinsic and extrinsic factors that dictate zonation patterns and new genomic approaches for studying zonation of parenchymal and non-parenchymal cells

Neonatal cholestasis is a group of disorders of impaired bile flow characterized by conjugated hyperbilirubinaemia that can be fatal if not treated rapidly. In this Review, aetiologies, algorithms for evaluation and current and emerging therapeutic options for neonatal cholestasis are discussed.

In a new study, the risk of new mental illness postpartum was significantly increased in women with IBD, and specifically in those with Crohn’s disease. Disturbingly, the risk of a substance disorder was also elevated in these women. The findings highlight that disease management during pregnancy is challenging and requires a multidisciplinary approach.

Ganesh et al. describe the rationale for using immunotherapy in select patients with colorectal cancer, discuss clinical findings supporting its use and highlight current strategies and future directions for expanding the scope of immunotherapy in this disease.

A new study shows that a sustainable faecal microbiota transplantation (FMT) treatment protocol, including anaerobic sample preparation, induces remission of active ulcerative colitis. The promising results are another piece in the puzzle, but it is not yet possible to draw conclusions and implement the procedure in clinical practice.

Cholangiocytes, which line the intrahepatic and extrahepatic bile ducts, are specialized cells that regulate bile production and homeostasis. Here, the authors discuss the role of cholangiocytes in development and liver regeneration, inflammation and fibrosis and their interactions with the immune system.

A new study provides evidence that colonization of germ-free mice with faecal bacteria from healthy infants can protect against signs of cow’s milk allergy in mice. The results from this and other studies raise the intriguing question of whether the gut microbiota can be manipulated for food allergy prevention and therapy.

The authors review the newest data on the gut fungal microbiota. They explore technical aspects of its analysis, how the mycobiome is influenced by immune and environmental factors, including fungi–bacteria interactions, and links between the mycobiota and gut diseases.

Disease presentation and progression within and across IBD are highly heterogeneous, particularly in Crohn’s disease. Here, the authors summarize genomic, epigenomic and gut microbiota studies in adult and paediatric patients that have identified different IBD subtypes.

Cancer-associated fibroblasts are critical components of the tumour mesenchyme. In this Review, the authors outline the emerging understanding of gastrointestinal cancer-associated fibroblasts with a particular emphasis on their origin and heterogeneity, as well as their function in cancer biology.

This Review summarizes current knowledge concerning the molecular subtyping of pancreatic cancer and explores future strategies using molecular taxonomy to guide therapeutic development and therapy with the overall goal of improving outcomes for this disease.

Two recent papers show that probiotics colonize the gut in permissive volunteers only and delay the reconstitution of the microbiome after antibiotics treatment. In the absence of any clinical readouts, it is still difficult to extrapolate these observations in terms of short-term or long-term health consequences for patients.

In this Review, the authors explore potential applications of big data in IBD research, including predictive models of disease course and response to therapy, characterization of disease heterogeneity, drug safety and development, precision medicine and cost-effectiveness of care.

A new study of a fibroblast growth factor 19 analogue in patients with primary sclerosing cholangitis (PSC) provides provocative results. The data challenge alkaline phosphatase levels as the appropriate surrogate end point in PSC trials and highlight alternatives, urging efforts to identify better clinical end points for this disease.

Over the past decade, many studies have revealed the importance of the gut microbiome in disease development and treatment, including in cancer. Because both host genetics and the gut microbiome can influence host phenotype and treatment outcome, there is an urgent need to develop precision medicine and personalize dietary supplementation based on an individual’s microbiome.

Alcoholic liver disease (ALD) is a leading cause of morbidity and mortality worldwide. Here, Bajaj discusses clinical studies on the gut microbiota in individuals with ALD and explores the specific alterations in the gut–liver–brain axis that might alter patient outcomes.