Jan A. Jacobs

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

ABSTRACT 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-α) release. Rats were administered lactobacilli (5 × 109 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-α release dose dependently, whereas CpG-ODN increased TNF-α 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.

Pretreatment with high-fat enteral nutrition reduces endotoxin and tumor necrosis factor-alpha and preserves gut barrier function early after hemorrhagic shock

Gram-negative sepsis is a potentially fatal clinical syndrome characterized by a proinflammatory response (tumor necrosis factor-&agr;) to bacterial (endo)toxins and gut barrier function loss. Recently, we found that high-fat enteral nutrition protects against late bacterial translocation in a model of hemorrhagic shock in rats. However, the basis for this protection is unknown. We hypothesized that the observed protection is the result of an early inhibition of endotoxin and the subsequent inflammatory response resulting in a preserved gut barrier function. Sprague–Dawley rats were divided into a group that was starved overnight (HS-S), fed with a low-fat enteral diet (HS-LF) or fed wih a high-fat enteral diet (HS-HF), and subsequently subjected to a nonlethal hemorrhagic shock. Ninety minutes after hemorrhage, arterial endotoxin significantly decreased in HS-HF rats (4.0 ± 0.6 pg/mL) compared with HS-LF rats (10.7 ± 0.9 pg/mL, P = 0.002) and HS-S rats (15.2 ± 2.2 pg/mL P = 0.001). Interestingly, arterial tumor necrosis factor-&agr; was also decreased in HS-HF rats (17.9 ± 10.4 pg/mL) compared with HS-LF (83.5 ± 16.7 pg/mL, P < 0.01) and HS-S rats (180.9 ± 67.9 pg/mL, P < 0.02). Loss of tight junction structure (ZO-1) observed in ileum and colon of control hemorrhagic shock rats was prevented in HS-HF rats. In parallel, intestinal barrier function was preserved in HS-HF rats, evidenced by a reduced permeability to horseradish peroxidase (P < 0.05), less bacterial invasion, and a 10-fold reduction of bacterial translocation early after hemorrhagic shock. This report describes a new strategy to nutritionally prevent endotoxemia, the subsequent inflammatory response and gut barrier failure following hemorrhagic shock. High-fat enteral nutrition requires further evaluation as an intervention to prevent a potentially fatal systemic inflammatory response in patients at risk for sepsis.

Enteral administration of high-fat nutrition before and directly after hemorrhagic shock reduces endotoxemia and bacterial translocation

Objective:To determine whether potential enhancement of endotoxin neutralization via high-fat enteral nutrition affects endotoxemia and bacterial translocation after hemorrhage. Summary Background Data:Endotoxin and bacterial translocation due to gut barrier failure are important initiating events in the pathogenesis of sepsis after hemorrhage. Systemic inhibition of endotoxin activity attenuates bacterial translocation and distant organ damage. Triacylglycerol-rich lipoproteins constitute a physiological means of binding and neutralizing endotoxin effectively. We hypothesized that enhancement of triacylglycerol-rich lipoproteins via high-fat enteral nutrition would reduce endotoxemia and prevent bacterial translocation. Methods:A rat model of nonlethal hemorrhagic shock was used. Hemorrhagic shock (HS) rats were divided into 3 groups: rats starved overnight (HS-S); rats fed with a low-fat enteral diet (HS-LF), and rats receiving a high-fat enteral diet (HS-HF). Results:Circulating triacylglycerol and apolipoprotein B, reflecting the amount of triacylglycerol-rich lipoproteins, were elevated in HS-HF rats compared with both HS-S rats (P ≤ 0.005 and P ≤ 0.05, respectively) and HS-LF rats (P ≤ 0.005 and P ≤ 0.05). Circulating endotoxin was lower in HS-HF rats (7.2 ± 10.2 pg/ml) compared with both HS-S rats (29.1 ± 13.4 pg/ml, P ≤ 0.005) and HS-LF rats (29.9 ± 5.2 pg/ml, P ≤ 0.005). In line, bacterial translocation was lower in HS-HF rats (incidence 4/8 rats; median 3 [range 0–144] cfu/g) compared with both HS-S rats (8/8; 212 [60–483] cfu/g; P = 0.006), and HS-LF rats (8/8; 86 [30–209] cfu/g; P = 0.002). Conclusion:This study is the first to show that high-fat enteral nutrition, leading to increased plasma triacylglycerol and apolipoprotein B levels, significantly decreases endotoxemia and bacterial translocation after hemorrhage.

External quality assessment of malaria microscopy in the Democratic Republic of the Congo.

BackgroundExternal quality assessments (EQA) are an alternative to cross-checking of blood slides in the quality control of malaria microscopy. This study reports the findings of an EQA of malaria microscopy in the Democratic Republic of the Congo (DRC).MethodsAfter validation, an EQA slide panel and a questionnaire were delivered to diagnostic laboratories in four provinces of DRC. The panel included three samples for diagnosis (sample 1: Plasmodium falciparum, 177,000/μl, sample 2: P. falciparum, 2,500/μl, sample 3: no parasites seen), one didactic sample (Howell-Jolly bodies) and one sample for assessing the quality of staining. Participating laboratories were addressed and selected through the network of the National Tuberculosis Control Programme. Participants were asked to return the responses together with a stained thin and thick blood film for evaluation of Giemsa stain quality.ResultsAmong 174 participants (response rate 95.1%), 26.2% scored samples 1, 2 and 3 correctly and 34.3%, 21.5% and 5.8% of participants reported major errors in one, two or three samples respectively. Major errors included reporting no malaria or non-falciparum malaria for Plasmodium falciparum-positive samples 1 and 2 (16.1% and 34.9% of participants respectively) and P. falciparum for Plasmodium negative sample 3 (24.0%). Howell-Jolly bodies (didactic sample) were not recognized by any of the participants but reported as P. falciparum by 16.7% of participants. With parasite density expressed according to the plus system, 16.1% and 21.5% of participants scored one + different from the reference score for samples 1 and 2 respectively and 9.7% and 2.9% participants scored more than two + different. When expressed as counts of asexual parasites/μl, more than two-thirds of results were outside the mean ± 2SD reference values. The quality of the Giemsa stain was poor, with less than 20% slides complying with all criteria assessed. Only one quarter of participants purchase Giemsa stain from suppliers of documented reliability and half of participants use a buffered staining solution. One third of participants had participated in a formal training about malaria diagnosis, half of them earlier than 2007.ConclusionThe present EQA revealed a poor quality of malaria microscopy in DRC.

Knowledge, attitudes and practice survey about antimicrobial resistance and prescribing among physicians in a hospital setting in Lima, Peru

BackgroundMisuse of antimicrobials (AMs) and antimicrobial resistance (AMR) are global concerns. The present study evaluated knowledge, attitudes and practices about AMR and AM prescribing among medical doctors in two large public hospitals in Lima, Peru, a middle-income country.MethodsCross-sectional study using a self-administered questionnaireResultsA total of 256 participants completed the questionnaire (response rate 82%). Theoretical knowledge was good (mean score of 6 ± 1.3 on 7 questions) in contrast to poor awareness (< 33%) of local AMR rates of key-pathogens. Participants strongly agreed that AMR is a problem worldwide (70%) and in Peru (65%), but less in their own practice (22%). AM overuse was perceived both for the community (96%) and the hospital settings (90%). Patients pressure to prescribing AMs was considered as contributing to AM overuse in the community (72%) more than in the hospital setting (50%). Confidence among AM prescribing was higher among attending physicians (82%) compared to residents (30%, p < 0.001%). Sources of information considered as very useful/useful included pocket-based AM prescribing guidelines (69%) and internet sources (62%). Fifty seven percent of participants regarded AMs in their hospitals to be of poor quality. Participants requested more AM prescribing educational programs (96%) and local AM guidelines (92%).ConclusionsThis survey revealed topics to address during future AM prescribing interventions such as dissemination of information about local AMR rates, promoting confidence in the quality of locally available AMs, redaction and dissemination of local AM guidelines and addressing the general public, and exploring the possibilities of internet-based training.

Exposure to Bacterial DNA Before Hemorrhagic Shock Strongly Aggravates Systemic Inflammation and Gut Barrier Loss via an IFN-γ-Dependent Route

Objective:To investigate the role of bacterial DNA in development of an excessive inflammatory response and loss of gut barrier loss following systemic hypotension. Summary Background Data:Bacterial infection may contribute to development of inflammatory complications following major surgery; however, the pathogenesis is not clear. A common denominator of bacterial infection is bacterial DNA characterized by unmethylated CpG motifs. Recently, it has been shown that bacterial DNA or synthetic oligodeoxynucleotides containing unmethylated CpG motifs (CpG-ODN) are immunostimulatory leading to release of inflammatory mediators. Methods:Rats were exposed to CpG-ODN prior to a nonlethal hemorrhagic shock. The role of interferon-gamma (IFN-γ) was investigated by administration of anti IFN-γ antibodies. Results:Exposure to CpG-ODN prior to hemorrhagic shock significantly augmented shock-induced release of IFN-γ, tumor necrosis factor-alpha (TNF-α) (P < 0.05), interleukin (IL)-6 (P < 0.05), and nitrite levels (P < 0.05), while there was a defective IL-10 response (P < 0.05). Simultaneously, expression of Toll-like receptor (TLR) 4 in the liver was markedly enhanced. Furthermore, intestinal permeability for HRP significantly increased and bacterial translocation was enhanced in hemorrhagic shock rats pretreated with CpG-ODN. Interestingly, inhibition of IFN-γ in CpG-treated animals reduced TNF-α (P < 0.05), IL-6 (P < 0.05), nitrite (P < 0.05), and intestinal permeability following hemorrhagic shock (P < 0.05) and down-regulated expression of TLR4. Conclusion:Exposure to bacterial DNA strongly aggravates the inflammatory response, disrupts the intestinal barrier, and up-regulates TLR4 expression in the liver following hemorrhagic shock. These effects are mediated via an IFN-γ-dependent route. In the clinical setting, bacterial DNA may be important in development of inflammatory complications in surgical patients with bacterial infection.

Patterns of inflammation and the use of reversibility testing in smokers with airway complaints.

BackgroundAlthough both smoking and respiratory complaints are very common, tools to improve diagnostic accuracy are scarce in primary care. This study aimed to reveal what inflammatory patterns prevail in clinically established diagnosis groups, and what factors are associated with eosinophilia.MethodInduced sputum and blood plasma of 59 primary care patients with COPD (n = 17), asthma (n = 11), chronic bronchitis (CB, n = 14) and smokers with no respiratory complaints (healthy smokers, n = 17) were collected, as well as lung function, smoking history and clinical work-up. Patterns of inflammatory markers per clinical diagnosis and factors associated with eosinophilia were analyzed by multiple regression analyses, the differences expressed in odds ratios (OR) with 95% confidence intervals.ResultsMultivariately, COPD was significantly associated with raised plasma-LBP (OR 1.2 [1.04–1.37]) and sTNF-R55 in sputum (OR 1.01 [1.001–1.01]), while HS expressed significantly lowered plasma-LBP (OR 0.8 [0.72–0.95]). Asthma was characterized by higher sputum eosinophilic counts (OR 1.3 [1.05–1.54]), while CB showed a significantly higher proportion of sputum lymphocytic counts (OR 1.5 [1.12–1.9]). Sputum eosinophilia was significantly associated with reversibility after adjusting for smoking, lung function, age, gender and allergy.ConclusionPatterns of inflammatory markers in a panel of blood plasma and sputum cells and mediators were discernable in clinical diagnosis groups of respiratory disease. COPD and so-called healthy smokers showed consistent opposite associations with plasma LBP, while chronic bronchitics showed relatively predominant lymphocytic inflammation compared to other diagnosis groups. Only sputum eosinophilia remained significantly associated with reversibility across the spectrum of respiratory disease in smokers with airway complaints.