1.

Doganci A, Neurath MF, Finotto S. Mucosal immunoregulation: transcription factors as possible therapeutic targets. Curr Drug Targets Inflamm Allergy. 2005 Oct;4(5):565-75. Review. Laboratory of Cellular and Molecular Lung Immunology and &Laboratory of Immunology, I Medical Clinic, University of Mainz, Germany.

Much progress has been recently made with regard to our understanding of the mucosal immune system in health and disease. In particular, it has been shown that uncontrolled mucosal immune responses driven by lymphocytes or non-lymphoid cells may lead to immunological diseases such as allergy, hypersensitivity and inflammation. Thus, a more detailed understanding of mucosal immune regulation and decision making at mucosal surfaces is essential for a better understanding of mucosal immune responses in health and disease. Antigen presenting cells and T lymphocytes play a key role in controlling mucosal immune responses. To deal with this key task, T helper cells differentiate into functionally distinct subsets: TH1 (CD4+ T Helper cells), TH2, TH3, Tr1, and CD4+CD25+ T (Treg) cells. This review summarizes the role of antigen presenting cells, eosinophils, mast cells and T-cell subsets in the pathogenesis of allergic inflammation and intestinal inflammation. Furthermore, we discuss novel immunological treatment modalities for allergic inflammation (e.g. allergic asthma) and chronic intestinal inflammation (e.g. inflammatory bowel diseases (IBD)) such as the control of the expression of transcription factors to redirect pathological immune responses.

2.

Du Pont HL. What's new in enteric infectious diseases at home and abroad. Curr Opin Infect Dis. 2005 Oct;18(5):407-12. Review.

School of Public Health, University of Texas-Houston, St. Luke's Episcopal Hospital, 6720 Bertner Avenue, MC 1-64, Houston, TX 77030, USA .

PURPOSE OF REVIEW: This review was designed to focus on the important research in the area of acute infectious diarrhea published within the past year. PubMed was reviewed for articles published in 2004 and 2005 relating to pathogen-specific diarrhea and for travelers' diarrhea to identify the newly published articles. RECENT FINDINGS: New studies continue to show the importance of the diarrheagenic Escherichia coli as causes of acute and persistent diarrhea. Enteroaggregative E. coli has recently been shown to be an unrecognized cause of community-acquired diarrhea in infants in the USA. Genetic factors explain an increased susceptibility to travelers' diarrhea among international travelers. Also, poorly non-absorbed rifaximin (< 0.4%) was shown to be an effective drug when used prophylactically to prevent bacterial diarrhea during high risk travel. SUMMARY: Studies will continue to define the etiology of diarrhea and to better understand the epidemiology and prevention of infectious diarrhea. Antibacterial resistance among enteric bacterial pathogens is a growing problem, leading to the search for newer antibacterial drugs. Diarrhea due to bacterial agents in international travelers can be prevented and treated successfully by antibacterial drugs. The nonabsorbed rifamycin drug, rifaximin, appears to be ideally suited to become the important new drug in prevention and treatment of travelers' diarrhea. Studies are underway to determine the value of the drug in preventing invasive forms of diarrhea during travel to Asia and in the prevention of the commonly occurring post-infectious irritable bowel syndrome.

3.

Jones NL, Wine E. Pediatric gastrointestinal diseases: are drugs the answer? Curr Opin Pharmacol. 2005 Dec;5(6):604-9.   Review.

Department of Paediatrics, Hospital for Sick Children, University of Toronto, Toronto, Canada. nicola.jones@sickkids.ca

Owing to the lack of large randomized controlled studies, which would produce level 1 evidence, to guide management of gastrointestinal disorders in children, data are often extrapolated from adult studies to aid in treatment strategies. However, there are unique aspects to the management of children and adolescents with these chronic diseases, including issues of growth, side effects, long-term outcomes and psychosocial factors that might not be considered in adult trials. There is a major need for increased research in this population. In the future, a better understanding of the pathophysiologic mechanisms of these diseases should guide the development of rational novel therapies with better safety profiles for children with gastrointestinal disorders.

4.

1.                   Mawdsley JE, Rampton DS. Psychological stress in IBD: new insights into pathogenic and therapeutic implications. Gut. 2005 Oct;54(10):1481-91. Review.

       Centre for Gastroenterology, Institute of Cell and Molecular Science, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK.

Psychological stress has long been reported anecdotally to increase disease activity in inflammatory bowel disease (IBD), and recent well designed studies have confirmed that adverse life events, chronic stress, and depression increase the likelihood of relapse in patients with quiescent IBD. This evidence is increasingly supported by studies of experimental stress in animal models of colitis. With the evolving concept of psychoneuroimmunology, the mechanisms by which the nervous system can affect immune function at both systemic and gut mucosal levels are gradually becoming apparent. Recent data suggest that stress induced alterations in gastrointestinal inflammation may be mediated through changes in hypothalamic-pituitary-adrenal (HPA) axis function and alterations in bacterial-mucosal interactions, and via mucosal mast cells and mediators such as corticotrophin releasing factor (CRF). To date, the therapeutic opportunities offered by stress reduction therapy remain largely unexplored, in part because of methodological difficulties of such studies. This paper reviews recent advances in our understanding of the pathogenic role of psychological stress in IBD and emphasises the need for controlled studies of the therapeutic potential of stress reduction.

5.

1.                   Panaccione R, Ferraz JG, Beck P. Advances in medical therapy of inflammatory bowel disease. Curr Opin Pharmacol. 2005 Dec;5(6):566-72.   Review.

Division of Gastroenterology, University of Calgary, Calgary, Alberta, Canada. rpanacci@ucalgary.ca

The past few years have seen increased knowledge and optimism on the use of biological therapy in Crohn's disease. Important lessons have been learned from the expanding clinical experience with infliximab, fuelling belief that current treatment will continue to evolve as therapy is aimed at specific targets within the immune cascade. Several other studies of agents that target tumour necrosis factor-alpha revealed mixed and sometimes disappointing results. However, this was balanced by encouraging results with agents that inhibit lymphocyte trafficking, as well as with other biological agents. Previous disappointing results of biological therapy in ulcerative colitis have been overcome with recent positive clinical trials with infliximab and the anti-CD3 antibody visilizumab. There now appears to be an expanding array of treatment options available to clinicians; however, as the number of potential molecular targets expands, unanswered questions remain regarding optimal treatment strategies, the long-term safety of biologicals and the ability of these novel and often expensive therapies to alter the natural history of the disease.

6.

1.                   Penner R, Fedorak RN, Madsen KL. Probiotics and nutraceuticals: non-medicinal treatments of gastrointestinal diseases. Curr Opin Pharmacol. 2005 Dec;5(6):596-603.   Review.

Division of Gastroenterology, University of Alberta, 6146 Dentistry Pharmacy, Edmonton, Alberta T6G 2N8, Canada.

The demonstration that immune and epithelial cells can discriminate between different microbial and bioactive plant species has extended the known mechanism(s) of action of nutraceuticals and probiotics beyond simple nutrition and/or antimicrobial effects. The progressive unravelling of these plant and bacterial effects on systemic immune and intestinal epithelial cell function has led to new credence for the use of probiotics and nutraceuticals in clinical medicine. Level I evidence now exists for the therapeutic use of probiotics in infectious diarrhea in children, recurrent Clostridium difficile-induced infections and post-operative pouchitis. Additional evidence is being acquired for the use of probiotics in other gastrointestinal infections, irritable bowel syndrome and inflammatory bowel disease. Not all individual probiotic strains have the same efficacy, and future clinical trials may focus on multistrain preparations agents with known efficacy. The use of nutraceuticals and probiotics as therapeutic agents for gastrointestinal disorders is rapidly moving into clinical usage. Scientific studies are providing mechanisms of action to explain the therapeutic effects, and randomized controlled trials are providing the necessary evidence for their incorporation into the therapeutic armamentarium.

7.

1.                   Woo PC, Lau SK, Teng JL, Yuen KY. Current status and future directions for Laribacter hongkongensis, a novel bacterium associated with gastroenteritis and traveller's diarrhoea. Curr Opin Infect Dis. 2005 Oct;18(5):413-9. Review.

Department of Microbiology and Research Centre of Infection and Immunology, Faculty of Medicine, The University of Hong Kong, Hong Kong, ROC.

PURPOSE OF REVIEW: Despite extensive investigations, a microbiological cause cannot be found in about half of the patients with infectious disease. Throughout the years, scientists have spent tremendous efforts in looking for microorganisms associated with these "unexplained infectious disease syndromes". Recently, a novel bacterium, Laribacter hongkongensis, was discovered and shown to be associated with gastroenteritis and traveller's diarrhoea. This review summarizes the current status, and shares with the readers the authors' experience in the microbiology, classification, epidemiology, clinical disease, laboratory diagnosis, antibiotic resistance and treatment of L. hongkongensis. It also discusses the importance and perspective of describing novel pathogenic bacterial species. RECENT FINDINGS: L. hongkongensis was shown to be associated with gastroenteritis and traveller's diarrhoea. Consumption of fish was associated with recovery of L. hongkongensis. Freshwater fish was a reservoir of L. hongkongensis. Genotypic typing revealed the possibility of virulent clones of L. hongkongensis. The class C beta-lactamase of L. hongkongensis has been cloned and characterized. SUMMARY: In 2001, L. hongkongensis, a novel genus and species, was first discovered in Hong Kong from the blood and empyema pus of a patient with alcoholic cirrhosis. Subsequently, it was isolated from patients in other parts of the world. Recently, this bacterium was found to be associated with community-acquired gastroenteritis and traveller's diarrhoea using cefoperazone MacConkey agar as the selective medium. Further studies, including setting up of animal and tissue culture models and characterization of virulence factors, should be performed. For pathogenic microbes, even one strain of a novel species should be described, so that global concerted efforts can be drawn to look for more cases associated with such a pathogen.