Carbohydrate supplementation before operation retains intestinal barrier function and lowers bacterial translocation in a rat model of major abdominal surgery.

BACKGROUND: Overnight fasting of rats augments the susceptibility of the small intestine to ischemia-reperfusion damage. Feeding before surgery may improve injuries to distant organs that were induced by ischemia-reperfusion. The present study tested the hypothesis that one of the food constituents, namely carbohydrates, may be responsible for the protective effect of preoperative feeding on postoperative organ dysfunction. METHODS: Male Wistar rats were fed ad libitum for 5 d and had either free access to water or free access to a carbohydrate drink and water. Then they were fasted for 16 h and access remained to either water or a carbohydrate drink and water. Following this, the arteria mesenterica superior was clamped for 60 min followed by 180 min of reperfusion. Subsequently, the intestinal permeability of stripped ileum was determined by measuring the mucosal to serosal flux in Ussing chambers. For assessment of bacterial content, organs were aseptically removed and assessed for bacterial content by culture under anaerobic conditions. RESULTS: Preoperative supplementation with carbohydrates resulted in a better maintenance of intestinal barrier function when compared with water supplemented animals. Moreover, carbohydrate supplementation resulted in a reduction in the ischemiareperfusion-induced increase in bacterial content of the liver, kidney, and mesenteric lymph nodes. CONCLUSIONS: Preoperative intake of carbohydrates by rats retains both the intestinal barrier function and prevents translocation of bacteria to distant organs.

Strain-specific effects of probiotics on gut barrier integrity following hemorrhagic shock.

Probiotic therapy modulates the composition of the intestinal flora and inhibits the inflammatory response. These properties may be of benefit in the preservation of gut barrier integrity after injury or stress. In this study, we examined the effect of two Lactobacillus strains selected for their pathogen exclusion properties on intestinal barrier integrity following hemorrhagic shock. Additionally, the responsiveness of the macrophage cell line RAW 264.7 to combined exposure to Lactobacillus DNA or oligodeoxynucleotides containing CpG motifs (CpG-ODN) and endotoxin was assessed by measuring tumor necrosis factor alpha (TNF-alpha) release. Rats were administered lactobacilli (5 x 10(9) CFU) or vehicle for 7 days and were subjected subsequently to hemorrhagic shock by withdrawal of 2.1 ml blood/100 g tissue. Levels of plasma endotoxin, bacterial translocation to distant organs, and filamentous actin (F-actin) in the ileum were determined 24 h later. Rats treated with Lactobacillus rhamnosus showed reduced levels of plasma endotoxin (8 +/- 2 pg/ml versus 24 +/- 4 pg/ml; P = 0.01), bacterial translocation (2 CFU/gram versus 369 CFU/gram; P < 0.01), and disruption of F-actin distribution following hemorrhagic shock compared with nontreated control rats. In contrast, pretreatment with Lactobacillus fermentum had no substantial effect on gut barrier integrity. Interestingly, DNA preparations from both lactobacilli reduced endotoxin-induced TNF-alpha release dose dependently, whereas CpG-ODN increased TNF-alpha release. In conclusion, the pathogen exclusion properties of both Lactobacillus strains and the reduction of endotoxin-induced inflammation by their DNA in vitro are not prerequisites for a beneficial effect of probiotic therapy on gut barrier function following hemorrhagic shock. Although pretreatment with Lactobacillus spp. may be useful to preserve gut barrier integrity following severe hypotension, a thorough assessment of specific strains seems to be essential.

Demonstration by a nested PCR for Mycoplasma pneumoniae that M. pneumoniae load in the throat is higher in patients hospitalised for M. pneumoniae infection than in non-hospitalised subjects.

A nested PCR protocol to detect Mycoplasma pneumoniae DNA in throat specimens was developed. An amplification control (AC) template, which is amplified by the same primers as the M. pneumoniae target sequence, was constructed. The assay allowed highly specific and sensitive detection of M. pneumoniae DNA. In all, 305 throat samples, 62 from hospitalised patients and 243 from non-hospitalised subjects, were analysed by the nested PCR. Inhibition of the PCR was observed in 20% of the samples, but was abolished after a 1 in 10 dilution. Throat samples from 5 (8%) of the hospitalised patients and from 7 (3%) of the non-hospitalised subjects were positive for M. pneumoniae DNA. To investigate the relationship between M. pneumoniae load and the severity of disease, the M. pneumoniae load in 10 throat samples from M. pneumoniae-positive subjects was assessed semi-quantitatively by application of the nested PCR to a series of limiting dilutions of nucleic acid extracted from these throat samples. The calculated M. pneumoniae load varied from 20 to 3830 cfu/ml of throat sample. The mean M. pneumoniae load in samples from the hospitalised patients was significantly higher than that in samples from the non-hospitalised subjects. The nested PCR is a useful tool to detect M. pneumoniae DNA in the throat and to study the relationship between the load of M. pneumoniae in throat samples and severity of disease due to M. pneumoniae infection.