Reviews & Analysis

2017 has witnessed key advances in knowledge about the metabolic capacities of the gut microbiota, enabling the progression of our understanding of the principles driving xenobiotic–bacteria–host interplay. This research paves the way for the long road towards personalized medicine and nutrition, which could be based on gut microbial metabolism.

Approximately half of patients diagnosed with oesophageal cancer have metastatic or unresectable disease. Here, the authors discuss the multidisciplinary interventions available to manage dysphagia, improve quality of life and prolong survival in these individuals.

The central studies published in 2017 address novel IBD therapeutic strategies and prediction of the future disease course or response to a distinct therapy. Together, these studies contribute to the understanding of the regulation of mucosal homeostasis and at the same time serve to develop novel personalized treatment algorithms in patients in whom a severe disease course can be predicted.

At the squamocolumnar junction of mice and humans,a new study has identified a unique population of transitional basal cells that express molecular markers of both oesophageal stratified squamous epithelium and gastrointestinal columnar epithelium. These transitional basal cells are an attractive candidate for the cell of origin for Barrett oesophagus.

Optogenetic and chemogenetic approaches hold great promise in neurogastroenterological research. In this Review, the authors discuss the advantages and limitations of available tools and cover optimal approaches for targeting specific cell types in the gut.

Cellular senescence is induced in response to various stresses and can either prevent or fuel disease and tumorigenesis. Here, the authors provide an overview of senescence aimed at gastroenterologists and hepatologists and detail how modulation of senescence might be used for therapeutic purposes.

Hepatitis E virus (HEV) is a public health concern in both developing and developed countries. Here, the authors describe advances in understanding HEV biology, clinical infection and the challenges still to be overcome in HEV research, particularly with respect to cell culture and animal models.

Environmental enteric dysfunction (EED) is an important cause of impaired development and stunting in children in the developing world. In this Consensus Statement, the authors assess the potential of optical biopsy technologies to facilitate the study and diagnosis of this global burden.

Chronic opioid use is increasing worldwide and has negative effects in the gastrointestinal and central nervous systems. This Review summarizes the evidence and consequences of opioid misuse in gastroenterology, as well as alternative pharmacological and nonpharmacological strategies for pain management in patients with gastrointestinal disorders.

Oncolytic viruses have made headlines owing to increasing numbers of reports of clinical success. Compelling data now indicate that small anticancer molecules can serve as potent sensitizers of tumour cells in hepatocellular carcinoma to enhance the oncolytic potential of systemically applied viruses.

Although Helicobacter pylori is associated with gastric cancer, bacterial communities that reside in the stomach are mostly unacknowledged. A new study shows that some gastric bacterial communities have emigrated from our mouth, prefer certain neighbours and prefer certain environments. By understanding the interactions of these bacteria, we hope to understand the environment most conducive to gastric cancer carcinogenesis.

Ileocaecal resection has traditionally been reserved for the treatment of biologic-refractory inflammatory, fibrostenotic or fistulizing Crohn's disease of the terminal ileum. Now, for the first time, this surgical approach has been investigated as an initial treatment for steroid or immunomodulator-refractory Crohn's ileitis, in comparison with anti-TNF therapy.

A wide variety of environmental triggers have been associated with IBD pathogenesis, including the gut microbiota, diet, pollution and early-life factors. This Review discusses the latest evidence and progress towards better understanding the environmental factors associated with IBD.

Traditionally, biopsy has been a mainstay and gold standard for the diagnosis of coeliac disease, but a biopsy-sparing approach has been suggested and adopted for the assessment of children in some countries. Here, the authors outline the current diagnostic methods for coeliac disease, discussing the pros and cons of a no-biopsy approach for both adults and children.

Bile acids link the gut microbiota to both hepatic and intestinal metabolism, and this tripartite relationship has been implicated in gastrointestinal disease. In this Review, the authors outline the mechanistic links between bile acid–microbiota crosstalk and gastrointestinal inflammation and carcinogenesis, with a specific emphasis on the major bile-acid-sensing receptors.

Childhood malnutrition is a global health issue influenced by poorly understood microbial interactions. A new model of co-infection in mice now sheds light on the complex interplay between pathogens, the host and the resident gut microbiota during malnutrition.

Following haematopoietic stem cell transplantation for the treatment of haematopoietic diseases, acute graft-versus-host disease (GVHD) of the gastrointestinal tract is a common complication that presents distinct diagnostic and therapeutic challenges. In this Review, the authors tailor their discussion of the diagnosis, staging and clinical management of gastrointestinal acute GVHD for practising gastroenterologists.

The diagnosis of GERD using functional oesophageal testing has been previously reported, but no updated expert recommendations have been made in over a decade. In this Consensus Statement, the authors describe modern oesophageal physiological tests and their analysis with an emphasis on establishing indications and interpretation parameters for evaluating GERD in clinical practice.

High-resolution manometry (HRM) has transformed our understanding of oesophageal motility disorders, in particular achalasia. In this Consensus Statement, the authors explore the effect HRM has had on the diagnosis and management of achalasia and related syndromes.

The presence of lymph node metastases (LNM) is considered one of the most important features of colorectal cancer (CRC) staging, indicating the need for additional surgery after local excision and adjuvant chemotherapy after surgery. Now, a new study challenges the role of LNM in the progression of CRC.