Review Articles, News & Views, Perspectives, Hypotheses, Analyses and Review in 2011

The gut microbiota is now widely recognized to have a central role in human health and disease, and can be manipulated to improve an individual's health. Fecal microbiota transplantation (FMT), as outlined in this Review, is one such approach to resolve dysbiosis of the gut microbiota and has therapeutic potential in a range of gastrointestinal diseases. The authors provide a broad overview of FMT and a timely update on the latest advances.

Treating pancreatic cancer can be challenging, as patients often have a poor prognosis and chemoresistance is common. As pancreatic cancer is fundamentally a genetic disease, the authors of this Review emphasize the complex mutational heterogeneity of pancreatic ductal adenocarcinomas and the importance of moving towards a model of tailoring therapies to the specific genetic characteristics of individual tumors.

Autoimmune pancreatitis (AIP) is becoming increasingly recognized as a unique form of chronic pancreatitis. Its diagnosis, based on clinical and pathological parameters, is challenging. AIP is currently divided clinicopathologically into type 1 and type 2. Histological diagnostic criteria for type 1 and type 2 AIP have now been proposed by an international consensus study.

As a result of its multifactorial nature, IBS poses a major therapeutic challenge in relation to what factors are best targeted. Hypnotherapy offers a unique solution to this problem by virtue of its ability to modify a wide range of pathophysiological processes to bring about symptomatic improvement.

Algorithms can predict the risk of rebleeding and mortality in patients with upper gastrointestinal bleeding, but not the risk of rebleeding following endoscopic treatment in patients with ulcers. A recent meta-analysis has addressed this issue, and could facilitate the development of methods to predict rebleeding and endoscopic treatments to reduce rebleeding.

Endoscopic palliation of malignant biliary obstruction or gastric outlet obstruction can be technically challenging and might require other interventions in some patients. Results from two recent studies suggest that nitinol self-expanding metal stents are safe and effective for both indications and might decrease the need for other interventions in these patients.

For colorectal cancer screening, the issue is no longer whether the fecal immunochemical test (FIT) is preferable to the guaiac fecal occult blood test, but how best to use the FIT. Using the OC-Sensor^™ FIT with a hemoglobin cut-off level of 50 ng/ml could offer the best cost-effectiveness ratio compared with nonscreening settings.

This Review describes interactions between intrahepatic cholangiocarcinoma cells and the surrounding stroma, with a focus on myofibroblastic cells. A 'human-like' orthotopic rat model and a new organotypic culture system have been developed, which can be used to test new therapies. Novel combination approaches to treatment that target both the cancer cells and cancer-promoting stromal cells are discussed.

Gastroesophageal reflux disease (GERD) is a chronic disorder that occurs when refluxate from the stomach comes into contact with the esophageal mucosa, typically causing symptoms such as heartburn and regurgitation. This Review focuses on the mucosal pathogenesis of GERD and describes new concepts in the role of mucosal inflammation in disease development in relation to the current model of GERD pathogenesis.

MRI could be used by clinicians as an effective tool to monitor patients with Crohn's disease. In this Review, Gionata Fiorino, Cristiana Bonifacio, Luca Balzarini, Alberto Malesci and Silvio Danese discuss the development of objective MRI-based scores that enable evaluation of the extent of intestinal damage. They also speculate on the generation of a new 'damage-driven' treatment paradigm—in which imaging is used to monitor intestinal damage and medication use is targeted to prevent the accumulation of further damage

Accurate estimation of standard liver volume (SLV) is one of the key factors for successful liver transplantation. Contrary to some misconceptions, SLV was developed for the sake of the recipient and not for the donor in living donor liver transplantation. A recent study evaluated the accuracy of five formulas for estimation of SLV, and investigated the effect of liver steatosis on errors in estimation.

Crohn's disease is a life-long illness, with patients increasingly being exposed to diagnostic medical radiation. Diagnostic strategies are being re-evaluated after concerns were raised over the long-term effects of medical radiation. A recent study explored the cost-effectiveness of a magnetic resonance enterography program in patients with Crohn's disease, which could reduce the risk of radiation-induced neoplasia.

Currently, vaccines are not widely used in the control of cholera, but new-generation orally administered vaccines may well become important tools in the public health armamentarium against this disease. This Review focuses on selected aspects of the disease, its pathogenesis and immunology, clinical features, epidemiology and treatment, and summarizes the status of new-generation cholera vaccines.

Pediatric liver transplantation is a major surgical challenge, especially in very small patients (≤5 kg), and existing literature on low-body-weight transplant recipients is limited. Two new studies discuss the possibilities and limitations of liver transplantation in very young infants and demonstrate encouraging results for liver transplantation in infancy.

An ideal diagnostic test should be quick, reliable and noninvasive. Fecal calprotectin is considered a marker of intestinal inflammation and has proven to be an effective test for IBD, but is fecal calprotectin a useful diagnostic tool when assessing patients with cirrhosis?

Over the past 10 years, most developed nation states have implemented mass population screening programs for colorectal cancer. Advances in the development of diagnostic molecular markers for colorectal cancer have yielded an expanding list of potential new screening modalities. The purpose of this Review is to summarize the different screening strategies that have been or are being investigated and to provide a critical evaluation of the performance data and relative merits of the potential new methods.

Hepatocellular carcinoma (HCC) is the third most common cause of death from cancer worldwide. In this Review Yan Li, Zhao-You Tang and Jin-Xuan Hou provide an overview of animal models that are relevant to HCC development, metastasis and treatment. Viral hepatitis is the single most important cause of HCC and the authors describe transgenic mouse models of HBV and HCV infection that have provided experimental evidence that viral genes could initiate or promote liver carcinogenesis. The criteria for establishing ideal HCC animal models are also discussed.

Campylobacter jejuniandC. coli are well-established human gastrointestinal pathogens, but other Campylobacterspecies (so-called emerging species) have also been shown to infect both humans and animals. In this Review, Man highlights the clinical importance of these emerging bacteria in both gastrointestinal and extragastrointestinal disease and describes the epidemiology, pathogenesis and transmission of these organisms.

Colorectal cancer (CRC) results from an accumulation of genetic and epigenetic changes in colon epithelial cells, which transforms them into adenocarcinomas. Over the past decade, major advances have been made in understanding cancer epigenetics, particularly regarding aberrant DNA methylation. Lao and Grady provide an overview of the role of epigenetics in CRC and discuss the clinical applications of these epigenetic alterations as biomarkers for early detection, diagnosis, prognostication and management of patients with CRC.

The multiple indications for liver transplantation make prioritization for organ allocation a hotly debated topic. Evidence is building that the current allocation system favors patients with hepatocellular carcinoma and should be replaced with one based on transplant benefit and not just survival.