Blockade of adenosine A2B receptors ameliorates murine colitis

Background and purpose: The adenosine 2B (A2B) receptor is the predominant adenosine receptor expressed in the colon. Acting through the A2B receptor, adenosine mediates chloride secretion, as well as fibronectin and interleukin (IL)-6 synthesis and secretion in intestinal epithelial cells. A2B receptor mRNA and protein expression are increased during human and murine colitis. However, the effect of the A2B receptor in the activation of the intestinal inflammatory response is not known. In this study, we examined the effect of A2B receptor antagonism on murine colitis. Experimental approach: Dextran sodium sulphate (DSS)-treated mice and piroxicam-treated IL-10/ mice were used as animal models of colitis. The A2B receptor-selective antagonist, ATL-801, was given in the diet. Key results: Mice fed ATL-801 along with DSS showed a significantly lower extent and severity of colitis than mice treated with DSS alone, as shown by reduced clinical symptoms, histological scores, IL-6 levels and proliferation indices. The administration of ATL-801 prevented weight loss, suppressed the inflammatory infiltrate into colonic mucosa and decreased epithelial hyperplasia in piroxicam-treated IL-10/ mice. IL-6 and keratinocyte-derived chemokine (KC) concentrations in the supernatants of colonic organ cultures from colitic mice were significantly reduced by ATL-801 administration. Conclusions and implications: Taken together, these data demonstrate that the intestinal epithelial A2B receptor is an important mediator of pro-inflammatory responses in the intestine and that A2B receptor blockade may be an effectiv

Heterologous Overexpression and Mutagenesis of the Human Bile Salt Export Pump (ABCB11) Using DREAM (Directed REcombination-Assisted Mutagenesis)

Homologous recombination in Saccharomyces cerevisiae is a well-studied process. Here, we describe a yeast-recombination-based approach to construct and mutate plasmids containing the cDNA of the human bile salt export pump (BSEP) that has been shown to be unstable in E. coli. Using this approach, we constructed the necessary plasmids for a heterologous overexpression of BSEP in the yeast Pichia pastoris. We then applied a new site-directed mutagenesis method, DREAM (Directed REcombination-Assisted Mutagenesis) that completely bypasses E. coli by using S. cerevisiae as the plasmid host with high mutagenesis efficiency. Finally, we show how to apply this strategy to unstable non-yeast plasmids by rapidly turning an existing mammalian BSEP expression construct into a S. cerevisiae-compatible plasmid and analyzing the impact of a BSEP mutation in several mammalian cell lines

Effects of adenosine A2A receptor activation and alanyl-glutamine in Clostridium difficile toxin-induced ileitis in rabbits and cecitis in mice

<p>Abstract</p> <p>Background</p> <p>Severe <it>Clostridium difficile </it>toxin-induced enteritis is characterized by exuberant intestinal tissue inflammation, epithelial disruption and diarrhea. Adenosine, through its action on the adenosine A_2Areceptor, prevents neutrophillic adhesion and oxidative burst and inhibits inflammatory cytokine production. Alanyl-glutamine enhances intestinal mucosal repair and decreases apoptosis of enterocytes. This study investigates the protection from enteritis by combination therapy with ATL 370, an adenosine A_2Areceptor agonist, and alanyl-glutamine in a rabbit and murine intestinal loop models of <it>C. difficile </it>toxin A-induced epithelial injury.</p> <p>Methods</p> <p>Toxin A with or without alanyl-glutamine was administered intraluminally to rabbit ileal or murine cecal loops. Animals were also given either PBS or ATL 370 parenterally. Ileal tissues were examined for secretion, histopathology, apoptosis, Cxcl1/KC and IL-10.</p> <p>Results</p> <p>ATL 370 decreased ileal secretion and histopathologic changes in loops treated with Toxin A. These effects were reversed by the A_2Areceptor antagonist, SCH 58261, in a dose-dependent manner. The combination of ATL 370 and alanyl-glutamine significantly further decreased ileal secretion, mucosal injury and apoptosis more than loops treated with either drug alone. ATL 370 and alanyl-glutamine also decreased intestinal tissue KC and IL-10.</p> <p>Conclusions</p> <p>Combination therapy with an adenosine A_2Areceptor agonist and alanyl-glutamine is effective in reversing <it>C. difficile </it>toxin A-induced epithelial injury, inflammation, secretion and apoptosis in animals and has therapeutic potential for the management of <it>C. difficile </it>infection.</p

Results of nutritional risk screening of patients admitted to hospital

Introduction To identify malnutrition, nutritional risk screening and assessment should be performed. A number of nutritional screening and assessment tools have been developed.       Materials and methods Authors monitored the nutritional state of 1266 patients using the MUST (Malnutrition Universal Screening Tool) method. Measurements and questioning were done at admission. The study was cross -sectional, presenting a snapshot about nutritional risk of patients.       Results In this study 21% of the patients had a BMI smaller than 20. 29% patients admitted to hospital lost at least 5% of their body weight in the 3 to 6 months before the admission. Altogether in this survey 41% of the patients are considered to be endangered concerning malnutrition! There is a statistically visible difference at BMI values between the disease groups.       Discussion If only body weight of patients is measured, the rate of malnutrition is about 20%. Using MUST the number of endangered patients is doubled. In these patients it is more likely that any complication would develop. Since there is no significant relation between the age and the risk group, MUST screening can be carried out on all patients. We intended to emphasize the necessity of nutritional risk assessment and nutritional therapy at all levels of health care