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We investigated the effects of the nature of the flooding amino acid on the rate of incorporation of tracer leucine into human skeletal muscle sampled by biopsy. Twenty-three healthy young men (24.5 ± 5.0 yr, 76.2 ± 8.3 kg) were studied in groups of four or five. First, the effects of flooding with phenylalanine, threonine, or arginine (all at 0.05 g/kg body wt) on the incorporation of tracer [13C]leucine were studied. Then the effects of flooding with labeled [13C]glycine [0.1 g/kg body wt, 20 atoms percent excess (APE)] and [13C]serine (0.05 g/kg body wt, 15 APE) on the incorporation of simultaneously infused [13C]leucine were investigated. When a large dose of phenylalanine or threonine was administered, incorporation of the tracer leucine was significantly increased (from 0.036 to 0.067 %/h and 0.037 to 0.070 %/h, respectively; each P < 0.01). However, when arginine, glycine, or serine was administered as a flooding dose, no stimulation of tracer leucine incorporation could be observed. These results, together with those previously obtained, suggest that large doses of individual essential, but not nonessential, amino acids are able to stimulate incorporation of constantly infused tracer amino acids into human muscle protein.

Aliment Pharmacol Ther 2010; 32: 872–883 Summary Background  Crohn’s disease is an inflammatory illness in which the immune response against gut microorganisms is believed to drive an abnormal immune response. Consequently, modification of mucosal bacterial communities, and the immune effects they elicit, might be used to modify the disease state. Aim  To investigate the effects of synbiotic consumption on disease processes in patients with Crohn's disease. Methods  A randomized, double‐blind placebo‐controlled trial was conducted involving 35 patients with active Crohn's disease, using a synbiotic comprising Bifidobacterium longum and Synergy 1. Clinical status was scored and rectal biopsies were collected at the start, and at 3‐ and 6‐month intervals. Transcription levels of immune markers and mucosal bacterial 16S rRNA gene copy numbers were quantified using real‐time PCR. Results  Significant improvements in clinical outcomes occurred with synbiotic consumption, with reductions in both Crohn's disease activity indices (P = 0.020) and histological scores (P = 0.018). The synbiotic had little effect on mucosal IL‐18, INF‐γ and IL‐1β; however, significant reductions occurred in TNF‐α expression in synbiotic patients at 3 months (P = 0.041), although not at 6 months. Mucosal bifidobacteria proliferated in synbiotic patients. Conclusion  Synbiotic consumption was effective in improving clinical symptoms in patients with active Crohn's disease.

Aim: Obesity in inflammatory bowel disease (IBD), particularly Crohn’s disease (CD), has previously been considered unusual (3%). CD patients who are obese tend to have increased perianal complications and a higher level of disease activity on an annual basis. Obesity in Scotland has been documented to have increased over the last decade, and over half all men and women in Scotland are now considered to be overweight. This study aims to assess obesity prevalence in the IBD community in Tayside, Scotland. Methods: All IBD patients (n = 1,269) were considered for inclusion. Inclusion criteria required a weight measurement taken from the preceding 12 months and a height measurement within the last decade. 489 patients were included in the analysis. Results: 18% of the Tayside IBD population were obese in comparison to approximately 23% of the Scottish population on a whole. A further 38% of patients were over-weight, the same percentage as the general population. In the overweight and obese ulcerative colitis patients there were higher levels of surgery, but the converse was true in the CD group, where the normal-weight group had the highest levels of surgery. There were significantly more obese men and women with CD than with ulcerative colitis (P = 0.05). Conclusion: Obesity prevalence has increased in IBD patients. This is significant because of the known increased levels of postoperative complications, perianal disease and requirement for more aggressive medical therapy. Research needs to be done to look at the effects of obesity on the co-morbid associations of other diseases with IBD, in particular colorectal cancer, and to ascertain whether or not screening frequency should be altered depending on BMI.

SUMMARY BackgroundAgeing can result in major changes in the composition and metabolic activities of bacterial populations in the large gut and an impaired immune system.

Enteral nutrition via a percutaneous endoscopic gastrostomy (PEG) tube is often part of management in patients with dysphagia due to neurological or oropharyngeal disease. Gastrostomy placement can affect normal innate defense mechanisms in the upper gut, resulting in bacterial overgrowth. In this study microbiological investigations were done with gastric and duodenal aspirates from 20 patients undergoing PEG tube placement and PEG tubes from 10 patients undergoing tube replacement. Aspirate and PEG tube microbiotas were assessed by using viable counts and selective solid media followed by aerobic and anaerobic incubation to assess cell viabilities. The antibiotic susceptibility profiles of the isolates were determined by the disk diffusion method, and gas chromatography was used to study the bacterial metabolic products in the aspirates. The aspirates and PEG tubes contained mainly streptococci, staphylococci, lactobacilli, yeasts, and enterobacteria. Enterococci were detected only in PEG tube biofilms and not in aspirates. Gastric pH affected the composition of the aspirate microbiotas but not the total microbial counts. Staphylococci, Escherichia coli, and Candida spp. were isolated only from antibiotic-treated patients, despite the sensitivities of the bacteria to the agents used. Antibiotic treatment had no effect on the incidence of infection or the length of hospital stay in these patients.

Patients with dysphagia due to oropharyngeal disease or cerebrovascular accident require long-term nutritional support via enteral feeding, which often results in microbial overgrowth in the upper gastrointestinal (GI) tract. Gastric acid is the primary innate defense mechanism in the stomach and has been assumed to provide an effective barrier to microbial colonization at pH values of <4. To evaluate the efficacy of gastric acid as a barrier to overgrowth, the microbiota of gastric and duodenal aspirates was assessed by culturing methods. Additionally, a fermentor-based model incorporating enteral nutrition tubing of the gastric microbiota of enteral nutrition (EN) patients was constructed to assess the effect of pH on the microbiota. Results showed that gastric acidity had a relatively small effect on the numbers of microorganisms recovered from intestinal aspirates but did influence microbiota composition. Similarly, at pH 3 in the fermentor, a complex microbiota developed in the planktonic phase and in biofilms. The effect of pH on microbiota composition was similar in aspirates and in the fermentors. Candidas and lactobacilli were aciduric, while recoveries of Escherichia coli and Klebsiella pneumoniae decreased as pH was reduced, although both were still present in significant numbers at pH 3. Only Staphylococcus aureus and Bifidobacterium adolescentis persisted at higher pH values both in vitro and in vivo. Lactate and acetate were the main organic acids detected in both aspirates and fermentors. These data show that the simulator used in this investigation was capable of modeling the effects of environmental influences on the upper GI microbiota of EN patients and that gastric pH of <4 is not sufficient to prevent microbial overgrowth in these individuals.

SUMMARY BackgroundCoeliac disease is more prevalent than was previously thought. The association between coeliac disease and cardiovascular outcome is not clear.