Review Articles in 2009

Replication of HBV occurs through reverse transcription, but inherent lack of proofreading causes a high rate of mutations. The most common naturally occurring HBV mutations are those in the precore and core promoter regions that abolish or decrease the production of hepatitis B e antigen. In this Review article, Chotiyaputta and Lok discuss these mutations and those that confer resistance to antiviral agents and/or facilitate escape from host immunity.

The late consequences of acute pancreatitis refer to the complications that can arise after the convalescence period of acute pancreatitis, that is, 3–6 months after the initial pancreatitis episode. The development of late complications correlates with disease recurrence. This Review discusses risk factors for the recurrence of acute pancreatitis and the late consequences associated with this disease.

Standard treatment with pegylated interferon and ribavirin only cures just over half of patients with HCV infection. Pereira and Jacobson review the evidence on the efficacy and promise of several specifically targeted antiviral therapies, which, most likely in combination with interferon and ribavirin, may improve the success rate of HCV therapy.

Pancreatic cancer is lethal and notoriously difficult to treat, therefore, there is an urgent need to develop new therapeutic and diagnostic modalities. This Review discusses the agents that have been developed to target the pathways and processes involved in pancreatic tumorigenesis, and reviews the results of laboratory and clinical trials of these agents. Future therapeutic targets are also discussed.

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. Treatment options for patients with advanced HCC are limited because of the lack of effective chemotherapeutic agents. This Review discusses the mechanisms of targeted therapies and describes clinical studies that have investigated the safety and efficacy of these therapies in patients with HCC. Perspectives for future developments are also provided.

Patients with Barrett esophagus and high-grade dysplasia or intramucosal carcinoma have traditionally been managed by esophagectomy. However, the development of endoscopic ablative therapies has changed this management approach. This Review discusses the different endoscopic ablative therapies currently available including tissue-acquiring and non-tissue-acquiring modalities. The success rates and complications of the different techniques are also addressed.

Advances in complementary metal oxide semiconductor technology have enabled the development of capsule endoscopy, a diagnostic technique that involves ingestion of a pill-sized camera that collects and relays still images of the tissues lining the gastrointestinal tract. Moglia and colleagues review the literature on the use of different capsule endoscopy devices for the inspection of the small bowel, esophagus and colon, and discuss the potential future applications and developments of this technology.

Ghrelin is an orexigenic hormone that acts to increase food intake and fat deposition, and at high doses, can modulate gastric motility. This Review addresses the actions of ghrelin in gastrointestinal systems. Studies that have investigated the role of ghrelin receptor agonists and antagonists for the treatment of gastrointestinal motility disorders and obesity are also discussed.

Appropriate clinical and pathological evaluation is crucial for the diagnosis and management of gastric polyps and polypoid lesions. This Review discusses the endoscopic characteristics, histopathology, pathogenesis and management of polyps and common polypoid lesions in the stomach, and provides a practical guide for gastroenterologists.

Effective cleansing of the colon is pivotal to achieve an accurate colonoscopy evaluation and affords many benefits, including improved visualization, reduced procedure times and reduced complication rates. This Review discusses the colonoscopy preparations available, with an emphasis on the efficacy, tolerability and safety of each method. Knowledge of the different approaches will enable physicians to choose the best preparation for their patients.

Increased risk of colorectal cancer in patients with IBD may be due to genomic instability caused by chronic colonic inflammation. This Review evaluates the alterations to gene expression and the genetic mutations associated with colitis-associated colorectal cancer and the clinical conditions that precede it. Feagins et al. identify potential molecular targets for colorectal cancer therapy that deserve further investigation.

Secondary sclerosing cholangitis is a chronic cholestatic biliary disease, which unlike primary sclerosing cholangitis, is thought to develop as a consequence of known injuries. The presence of sclerosing cholangitis in critically ill patients is a new entity that is increasingly recognized. This Review discusses the features, diagnosis, pathogenesis and treatment options for secondary sclerosing cholangitis and sclerosing cholangitis in critically ill patients.

In this article, Rhee and colleagues review the ample preclinical evidence suggesting that the commensal bacterial flora physiologically present in the gut modulates and influences bidirectional communication between the host's gut and central nervous system. The authors propose possible mechanisms by which these three-way mutual interactions may occur and may affect the host's healthy and diseased states.

Eosinophilic esophagitis is a chronic esophageal inflammatory disease of undetermined pathophysiology resulting in dense mucosal eosinophilia and esophageal dysfunction. This Review discusses the disease in terms of its clinical presentation in children and adults, pathogenesis, diagnosis and treatment.

Gastrointestinal stromal cell tumors (GISTs) always have a degree of malignant potential, and, increasingly, they are diagnosed only on routine endoscopy. Sepe and Brugge provide a gastroenterologist's guide for GIST diagnosis and assessment of malignant potential. The authors of this Review also propose an algorithm for the treatment of localized GISTs that is especially useful for the management of incidentally diagnosed tumors.

HCV infection is a key cause of liver disease and a worldwide health problem. The authors of this Review discuss the HCV life cycle and the mechanisms that enable the virus to evade host immune mechanisms and persist within the host. Improved understanding of HCV survival strategies should facilitate the development of effective antiviral therapies.

Intestinal fibrosis is a common and potentially serious complication of IBD. The traditional view that the development of fibrosis in these patients is inevitable and irreversible is progressively changing with improved understanding of the pathogenic mechanisms of fibrosis. This Review discusses the complex general mechanisms of fibrosis and addresses specific issues related to intestinal fibrosis in the setting of IBD, including the potential implications of novel treatments.

Several endocrine disorders are thought to have a role in the etiology of chronic liver disease and the development of nonalcoholic steatohepatitis. This Review discusses the evidence that causally links hormonal disorders, including thyroid disorders, growth hormone and adrenal insufficiency and polycystic ovary syndrome with liver disease. The role of hormone replacement to normalize liver function in some patients is also discussed.

This review discusses advances in enteral access procedures that have considerably broadened the indications for tube feeding and have led to a substantial reduction in the need for total parenteral nutrition. Enteral feeding can now be given to most patients in the intensive care, and is associated with improved outcomes.

The development of multimodality and targeted treatment strategies has improved the prognosis of patients with gastrointestinal cancers. Not all patients, however, benefit equally from these treatment approaches, and the ability to predict who will respond positively to a treatment type is of particular importance. This Review discusses the role of biomarkers and metabolic imaging approaches in the prediction of response to therapy early on in treatment.